page title icon Can Cats Eat Chocolate?
by Linda Mathews Last Updated February 4, 2021
Cats are very curious. Despite they are rather picky eaters, they will never miss an opportunity to explore and taste what you are savoring so much. Especially, they are interested when eating that treat is preceded by the unfolding of its wrapper. So shiny, so beckoning – your kitty just can't resist it.
Many cat owners say that their pets like eating chocolate, candies, ice cream. At first glance, it may seem that cats do it consciously, enjoying the taste of sweets. But that's not true: cats, being true predators, do not feel the taste of sugar at all.
When a cat eats chocolate, it feels the taste of vegetable fats, milk, nuts, but not sugar.
The thing is the cat DNA lacks the TAS1R2 gene, which is responsible for the perception of sweet taste. In comparison, human DNA includes this gene along with the TAS1R3 gene, allowing us to distinguish different sweet tastes.
For omnivores and herbivores, this skill is necessary, since they need carbohydrates, which are abundant in sweet food. Since carnivores (which the cats are) need a large amount of protein rather than carbohydrates, sugar for cats is useless. Therefore, it is not necessary for felines to taste it. It is much more important to recognize the protein, and a kitty is a great one for it!
No matter what their real nature is, lots of cats eat chocolate, making their owners worry and look for answers. Is chocolate poisonous to cats? Is chocolate toxic to cats? Can I give my cat chocolate if it likes it? Is it dangerous to treat my kitty with sweets from time to time? What should I do if my cat was fed with chocolate? Let's deal with this once and for all!
Is Chocolate Bad For Cats?
Is Chocolate Bad For Cats
Definitely YES.
Of course, it is not toxic in small amounts and you have no reasons to worry if your cat has licked or bitten a little piece of chocolate. However, eating more can be fatal and requires emergency vet care.
But what is that "small amount" of chocolate and how much is too much for cats? It depends on the weight of your pet, the amount of chocolate, and the concentration of theobromine in it. As little as 20 mg per pound of cat can cause health problems.
This toxic agent is a component of all kinds of chocolate, including white chocolate. The darker the chocolate is, the more dangerous it is. In the order of theobromine concentration, here is the list from least to worst (for 100g of chocolate):
 1. Vegan chocolate (very low level)
 2. White chocolate (about 10mg)
 3. Milk chocolate (about 200mg)
 4. Dark chocolate (802-493mg)
 5. Unsweetened baking chocolate (1297 mg)
Besides theobromine, milk and dark chocolate also contain caffeine, which affects feline nervous system badly.
For sure, chocolate has a positive effect as well – it's made of cocoa beans, which offer calcium, iron, vitamins (A, C, E), fiber, protein, and other important nutrients. But the harm from theobromine and caffeine is much more destructive.
Why Is Chocolate Bad For Cats?
 - Reason 1 – Theobromine
Theobromine in small amounts acts as a diuretic, causing increased loss of body fluids, and as a stimulant, leading to increased blood pressure, heart rate, also causes gastrointestinal upset, and the nervous system problems.
As cat body can't break theobromine down and eliminate it like humans, in bigger amounts it can even cause general intoxication and death of a pet. The first symptoms of a cat's critical condition during the theobromine poison are vomiting and diarrhea.
In such case, you should immediately contact the veterinarian and collect the vomit for the laboratory test.
 - Reason 2 – Sugar
Since cats can't taste sugar, they eat chocolate and other sweets because of the protein, which is the basis of any predator's diet, and don't suspect that they also consume lots of harmful sugar as well.
 - Reason 3 – Carbohydrates
A cat, which lives in an apartment, consumes little energy since it has no need to hunt or protect its territory. Carbohydrates (such as sugar) are stored "in reserve". They turn into fat under the skin and in the tissues of organs, eventually leading to a decrease in their functionality. Finally, your pussycat will end up overweight or obese, significantly shortening its life expectancy.
 - Reason 4 – Diabetes
As the cat's body is not meant to absorb a large amount of glucose, eating chocolate can lead to lack of insulin, which in turn leads to a violation of protein metabolism in the feline body. Thus, the level of glucose in the blood and urine increases and diabetes develops.
 - Reason 5 – Immune System
Also, chocolate and sweets reduce the protective functions of the cat's body.
Since the intestinal immune system has more protective cells than the respiratory immune system, it's very important to keep it at the highest level. But all kinds of sweet products are bad for the entire digestive system of the cat (including the intestines) – it is just not built for the digestion of such products.
Chocolate is the most dangerous for young and aging cats, pregnant and lactating cats, kittens, and cats with chronic illnesses.
Symptoms of Chocolate Poisoning in Cats
 - Nervousness
 - Increased reflex responses
 - Hyperactivity
 - Restlessness
 - Tremors/muscle twitching
 - Muscle rigidity
 - Rapid breathing
 - Lethargy
 - Excessive thirst
 - Nausea
 - Vomiting
 - Diarrhea
 - Excessive urination
 - Seizures
 - Abnormal heart rhythm
 - Arrhythmia
 - Heart attack
 - Increased body temperature
What to Do If Your Cat Eats Chocolate
What to Do if Your Cat Eats Chocolate
First of all, observe the cat for a while. It is very important to notice the onset of symptoms of poisoning. If you catch your cat eating chocolate, take him to the vet immediately.
Are Cats Allergic To Chocolate?
Chocolate is poisonous to cats, but they are not allergic to it.
Allergy means that the product is harmless for the body, but the immune system overreacts to it, causing some typical symptoms as a result. As we already know, chocolate contains some dangerous components, which cause more severe health problems than a regular allergy.
However, individual cats can be allergic to chocolate, but such cases are very rare.
How Much Chocolate Can A Cat Eat? Can Cats Die From Eating Chocolate?
We already know how harmful the bitter alkaloid theobromine can be for our little feline friends. But it can hurt even more, leading to coma or death. The average lethal dose for a cat is the amount of chocolate containing 200mg of theobromine.
Does chocolate kill cats? – Yes, it does!
How to Prevent Chocolate Toxicity in Cats
Keep chocolate out of reach of cats. Cats are very curious creatures, and they can be very cunning at times, so make sure your pet can't get to the chocolate. If you want to please your pet, then get special cat treats.
Cat Chocolate Toxicity Treatment
Emergency relief for chocolate poisoning is to induce vomiting. Veterinarians examine the internal organs of the feline and take blood and urine tests. Often, veterinarians prescribe a soft diet for several days.
To Sum Up
Stop thinking like "Can my kitty be allowed to eat a chocolate treat once in a while?" – It's a definite huge NO-NO.
Make sure that every member of your family knows and understands the risks of chocolate for pets, always call the vet if something's wrong with your cat, and keep the level of chocolate in your kitty's diet at a firm zero.


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Saltos de línea: cor¦don
Pronunciación: /ˈkɔːd(ə)n
Definición de cordon en inglés:
1A line or circle of police, soldiers, or guards preventing access to or from an area or building: the crowd was halted in front of the police cordon
Más ejemplos en oraciones
 - Following the discovery, police threw a cordon round the area and set up a 24-hour guard to protect the site.
 - Soldiers forming a cordon around the police station became involved, and a wall was demolished by a British tank as they struggled to 'collect' the men, the MoD said.
barrier, line, column, row, file, ranks, chain, ring, circle;
informal crocodile
2A fruit tree trained to grow as a single stem.
Example sentences
 - Somebody recently showed me five different varieties of apples on cordons (single stems grown at 45 degrees to the ground) against a 4ft featherboard fence.
 - Vines are generally cordon or single Guyot trained.
 - Specimen half-standard fruit trees can be grown as features in the lawn or borders, and mini upright cordons can be grown individually, in small plantations in the borders or in pots for the patio.
3 Architecture A projecting course of brick or stone on the face of a wall.
[with object] (cordon something off) Volver al principio
Prevent access to or from an area or building by surrounding it with police or other guards: the city centre was cordoned off after fires were discovered in two stores
Más ejemplos en oraciones
 - A large area surrounding the house has been cordoned off by police tape.
 - People living nearby were woken with the news at around 3am and the area was cordoned off by police tape.
 - The crews were at the scene for four hours and the area was cordoned off as police and fire investigation officers began an examination the scene.
late Middle English (denoting an ornamental braid): from Italian cordone, augmentative of corda, and French cordon, diminutive of corde, both from Latin chorda'string, rope' (see cord). sense 3 of the noun, the earliest of the current noun senses, dates from the early 18th century.
Words that rhyme with cordon
Auden, broaden, Gordon, Hordern, Jordan, warden
Definición de cordon en:
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Palabra del día gourmand
Pronunciación: ˈɡʊəmənd
a person who enjoys eating…


Structure scanning plot
In CLC Genomics Workbench it is possible to scan larger sequences for the existence of local conserved RNA structures. The structure scanning approach is similar in spirit to the works of [Workman and Krogh, 1999] and [Clote et al., 2005]. The idea is that if natural selection is operating to maintain a stable local structure in a given region, then the minimum free energy of the region will be markedly lower than the minimum free energy found when the nucleotides of the subsequence are distributed in random order.
The algorithm works by sliding a window along the sequence. Within the window, the minimum free energy of the subsequence is calculated. To evaluate the significance of the local structure signal its minimum free energy is compared to a background distribution of minimum free energies obtained from shuffled sequences, using $ Z$-scores [Rivas and Eddy, 2000]. The $ Z$-score statistics corresponds to the number of standard deviations by which the minimum free energy of the original sequence deviates from the average energy of the shuffled sequences. For a given $ Z$-score, the statistical significance is evaluated as the probability of observing a more extreme $ Z$-score under the assumption that $ Z$-scores are normally distributed [Rivas and Eddy, 2000].


PhD Programme Environmental Policy Analysis
The PhD research in the department of Environmental Policy Analysis (EPA) focuses on the theme of governance for sustainability. Governance has become a key concept in policy research, where it denotes the departure from old-style government to new forms of horizontal and vertical steering. This generally includes a transition from bureaucratic, centralized top-down policies to new forms of decision-making that are more inclusive, more decentralized, more flexible, less hierarchical, and more complex.
Within this context, we investigate several overarching questions: for example, how effective are modern systems of environmental governance in achieving the transition to sustainability? Which theories can best explain variation in the effectiveness of different forms of governance? How can we scrutinize unintended effects? How does a multitude of institutions that co-exist with an issue area interlink, overlap, and interact? How do unsustainable practices change into sustainable ones? And finally, how can we stimulate innovation in terms of governance approaches?
The EPA department runs PhD research projects linked to their three Research themes: Governing under Complexity; Governance Innovation and Institutional change; and Governance Evaluation (more information here).
Enrolment: see PhD enrolment.
For more information or applications, please contact Prof. Philipp Pattberg or Prof. Dave Huitema.


Can You Deposit A Check Without A Signature?
 - Post category:Money Misc.
Financial checks are designed to let people exchange money directly between bank accounts. Because these accounts and your money should remain secure, both parties — the giving and receiving — are required to permit the money to be exchanged. The payer does this by signing the check. But what happens if the payer gives you a check that they didn't sign? We've researched this and have come up with the answer.
Some banks will let you deposit a check that wasn't signed but will ask for a guarantee that you are the intended payee. Check with your bank to learn their policies. Your best bet is to ask the payer to rewrite the check, filling it out correctly.
We understand that your money is important to you, so we're excited to help you understand how to solve this problem. Please read on for more information about depositing checks, correcting errors, and other related topics. Let's get started!
Businessman's Hand Signing Check On Glass Desk, Can You Deposit A Check Without A Signature?
Can you deposit a check without a signature?
Woman's hand writing a check to pay the bills, with calculator and an invoice on the desktop
Banks require a signature from the person whose account will be charged the amount written on the check. This is generally an effective way to verify that the person is giving the money to the payee. It eliminates fraud in most cases since the payer's signature can be matched with what's written on the check in the case of a dispute.
In general, the payer is not liable for a check unless they've signed it; that's the verifiable way to process the money. However, if the person forgot to sign at all but has given a person the check, they will still be on the hook for it. Treat it like a bad check: the payer still owes you the money.
The best way to make sure this never happens is to make sure the payer has signed the check before accepting it. You should proofread any check given to you to allow the payer to correct any errors, not just forgetting to sign it. That will save you an awkward and potentially confrontational conversation later.
That's not always possible, like in the case of a business that prints their checks or if someone has mailed one to you. If you've received a check that isn't signed, you have a couple of options. The first is to ask the payer to write you a new one. If this is a person with whom you've done business before or is someone you know and trust, this shouldn't be a problem.
If it's a stranger or a business of some sort, this might be trickier. You can ask your bank about their particular policy. Some will absolutely not accept an unsigned check for any reason. Others, though, might have a way around the issue.
Guaranteeing a Check
For instance, one common fix is to "guarantee" the check. Essentially what you're doing is giving your word that this check was given to you in good faith, even though it was unsigned. If your bank accepts this, they're assuming that there won't be a problem. If there is a dispute from the payer, your bank will have a process that you must undergo.
To guarantee a check, endorse it like normal. Then, in the endorsement section, add a line that says "lack of signature guaranteed." If you can, take the check to a teller and deposit it in person. This is the best way to ensure that it will be deposited.
Forgetting to sign a check might not be a correctable mistake. However, there are some check-writing errors that you can correct. This article has more details: "How to Correct a Mistake on a Check."
What Happens If You Deposit A Check Without Signing It?
If you deposit a check without signing it — also known as endorsing it — there's a good chance that it will get rejected. Endorsing the check is a process that includes signing it and verifies that the money will go to the correct person and account. Most banks ask for it as a way to reduce errors or fraudulent activity.
If you take your check into a bank to deposit it, the teller should look for an endorsement as soon as you hand it to them. You'll be asked to endorse it before he or she deposits it into your account. You'll also be asked which account you'd like the money to be deposited, or whether or not you'd like to cash it.
At an ATM or via mobile deposit, not signing the check could lead to it being rejected. Oftentimes, the automated system will accept the check at first but will catch the error later in the process. With a mobile deposit, that shouldn't be a problem since you can then endorse the check and try again. But at an ATM that has already taken the check, you'll need to ask for the payer to write another one.
Where Do You Endorse A Check With No Line?
The check's endorsement section is usually one and a half inches long and the same width as the check. Usually, you can find it on the same end as the numeric amount is on the front. Oftentimes this section will be marked by a box and instructions such as "endorse here."
This is still the endorsement section, even if it isn't explicitly outlined or doesn't have a signature line. In this case, go ahead and endorse the check as you normally would. Try to keep it all within the one and a half-inch area and put your signature at the top.
Want more information about endorsing checks? Read this article: "What Does Endorsing a Check Mean?
Can Someone Deposit A Check For You?
Someone can deposit a check for you in person as long as you've endorsed the check, or the person who's depositing it writes the phrase "for deposit only" in the endorsement section. Basically, the bank won't have a problem depositing money into your account as long as you're the intended recipient. There are a few ways to make this process easier for the friend who's helping you deposit it.
The most secure way to make sure the money gets into your account is to write a deposit slip for your friend. A deposit slip is a form used by many banks to make the teller's job easier and ensure that everything is happening appropriately. If you have a deposit slip handy, fill one out and give it to your friend with the check.
Assuming you don't have a stack of deposit slips at home, you can write the account number in the endorsement section, under your signature. This will help the bank make sure it gets into the right account since you aren't there to show them identification. For further safety, write the phrase "for deposit only" in the endorsement section.
In fact, you don't even have to write your account number in the endorsement section if you don't want to. The phrase "for deposit only" means that your friend can't cash the check, which means the teller won't give them cash in exchange for the check. The riskiest thing you can do when asking someone else to deposit a check for you is to sign it only. This is called a "blank endorsement." This lets the person depositing it tell the teller they want to cash it.
In Closing
If a person writes you a check but forgets to sign it, consider asking them to rewrite it. If that's unreasonable or impossible, your bank might let you guarantee the check, even if it doesn't have a signature. You'll have to check with your bank's specific regulations. Also, pay attention to how you endorse checks to make sure it gets into the right account.
We hope this article has shown you how to handle this unfortunate situation. Good luck!


Skip to definition.
Noun: hexane 'hek,seyn
 1. A colourless flammable liquid alkane derived from petroleum and used as a solvent
Derived forms: hexanes
Type of: alkane, alkane series, dissolvent, dissolver, dissolving agent, methane series, paraffin, paraffin series, resolvent, solvent
Encyclopedia: Hexane


text:
On January 5, 1875, Fargo was incorporated as a city. Shortly after that, John E. Haggart was elected Fargo Police chief.
One of the first problems encountered by the police department was the lack of a "lock-up." A jail and a yard were rented for $15 per month from June 1875 until August 1876. In 1876, a simple wood plank jail was built on 1st Avenue South between 3rd and 4th Streets at a cost of $197. The city also purchased a ball and chain for prisoners at a cost of $8.
By 1881, the police department had grown to 10 members. The title "town marshall" was changed to "chief of police." The chief had one sergeant and eight patrolmen on his staff. In the same year, John Haggart was elected Cass County Sheriff and George Holes became the Fargo chief of police.
The duties of police officers were much more than just keeping order. In 1881, the dayshift police were ordered to purchase a barrel of oil. They were required to keep the street lamps in good working condition and full of oil. The nightshift police had the job of lighting and extinguishing the lamps. In 1888, the chief of police was given the job of opening and closing the bridges on the Red River. He received a monthly bonus of $10 for this task.
In April 1882, the first uniforms were issued to Fargo Police Officers. At that time, the police chief earned $100 per month, the sergeant made $80 per month, and the patrolman made $75. In 1888, the department purchased two Colt revolvers.
In December 1898, the department was authorized to hire its first detective. Martin Flanigan was appointed to this position.
Fargo had traffic problems even in the late 1800s. "Scorching" was a term to describe driving a horse and buggy on the streets at more than eight miles per hour. Speeding bicycles also became a problem on city streets. In 1898, all officers were issued "Crimson Rim bicycles" to help combat traffic problems.
In 1910, a car was hired to enforce speed laws. Call boxes equipped with bells were installed in strategic locations so citizens could contact officers; these remained in use until the 1970s. In 1915, the department purchased squad cars for the officers.
By 1929, the department had grown to a total of 27 officer, including the chief, captain, desk sergeant, two drivers, two motorcycle men, two car markers, three detectives and fifteen uniformed officers.
The first radio system was installed in 1935. The system was very limited, only permitting one-way voice transmission from the police department to the car. There was no way to make sure the officers heard the message, so dispatchers were required to repeat the message three times. In 1947 and 1969, more modern two-way radio systems were installed.

source: HuggingFaceFW/fineweb-edu


text:
1. General: Written definition, limit, or rule, approved and monitored for compliance by an authoritative agency or professional or recognized body as a minimum acceptable benchmark. Standards may be classified as (1) government or statutory agency standards and specifications enforced by law, (2) proprietary standards developed by a firm or organization and placed in public domain to encourage their widespread use, and (3) voluntary standards established by consultation and consensus and available for use by any person, organization, or industry. Once established, standards (like bureaucracies) are very difficult to change or dislodge. For example, the world standard for broad gauge railway line is 4 feet and 8½ inches between the parallel tracks. This odd figure has its origin in the axle-width of Roman army chariots designed to accommodate the rear ends of two horses yoked side-by-side.
2. GATT definition: "Technical specifications contained in a document that lays characteristics of a product such as levels of quality, performance, safety, or dimensions. Standards may include or deal exclusively with terminology, symbols, testing and methods, packaging, or labeling requirements as they apply to a product." See also standard.


text:
When you install programs or games on any Windows version and build, you may periodically encounter an error 5, which provides the system with the error message like «Setup was unable to create the directory. Error 5: Access is denied». Most often this occurs on systems where there are multiple user accounts and on this page we present ways to correct the error 5 in Windows OS.
Reasons of error 5 occurrence in Windows
To install programs or games, Windows automatically creates a temporary copy of the installation files from the disk or flash drive to your hard disk, places them in a special directory and installs from there. This temporary directory is located at% USERPROFILE%\AppData\Local\Temp or % WINDIR%\Temp. And if the system cannot get access to this directory or cannot run a particular file from that directory Windows will automatically show an error 5.
The reason is the behavior of the system with the most banal lack of rights to read and write data from the temporary folder with a specific user.
How to fix error 5
- In order that the system has received all the necessary rights to work with the temporary folders and files that are in it, sometimes it is enough to run the installer of game or application on behalf of the Administrator. If you use a normal user account on your PC, you may need an administrator password.
- In order to enable access to work with the folder to all PC users, you must perform the following steps:
- Press Win + R.
- Enter %USERPROFILE%\AppData\Local\.
- Select the Temp folder, and then open its properties, using the right mouse button.
- Click on Security tab.
- Select «CREATOR-OWNER» in the category «Groups and Users».
- In the new window set permits of full access and confirm.
- The same operation must be run with the parameters «system», «TrustedInstaller», «Community» and «Administrators».
- All the steps in method 2 can also be done with a directory located at %WINDIR%\.
To enter your changes, restart the computer and try to install programs or games.
- If the above methods do not give the expected result, you can go to a slightly different way and simply change the address of the temporary folder by changing Windows settings
- Create a directory at the root of the system drive and give it any name. For example, it can be a directory Temp. Фddress should look like this: C: \ Temp, where C — is the letter of the system partition, and Temp — the name of the new directory.
- Open the properties of your computer, right click on the My Computer icon.
- In the left column of the window that opens, locate the «Advanced System Settings» and open them.
- In the System window, click «Advanced» and then «Environment Variables».
- Select Temp folder and set it to a new address.
After the changes required try to restart your computer and to install programs. Error 5 will no longer disturb the users of your PC.

source: openbmb/Ultra-FineWeb


Deep Freeze Unfreezer
Deep Freeze Unfreezer!
Learn how to bypass Deep Freeze
 Main | Forum | Contact
How to manually uninstall Deep Freeze
for Windows 2K/XP
by Emiliano Scavuzzo
 If you are reading this tutorial you'd probably know that Deep Freeze not always work the way it should and sometimes it can do more damage than good. Some common scenarios include the installer not being able to uninstall DF even when the disks are thawed, Deep Unfreezer not being able to thaw the disks or something worst: the system fails to boot. This tutorial explains how to manually uninstall Deep Freeze by removing it's core driver from the registry and therefore completely disabling it. This tutorial doesn't explain how to do a complete uninstallation, though. There's a lot of garbage Deep Freeze installs on the disk and registry that you'll have to find yourself, but remember that this garbage can't prevent the computer from booting or freeze the disks. You can always try to restore the registry from a point before installing Deep Freeze by using the backups saved on %windir%\repair or System Volume Information.
 This tutorial is intended for advanced users. If you don't even know what the registry is you shouldn't follow these instructions. Playing with the registry is dangerous and you could damage your system by doing so.
Always make backup copies of the registry files before trying this tutorial.
Without a complete uninstallation you may not be able to reinstall Deep Freeze on your system.
Let's get to work:
1. First we need a way to edit the registry. The way to do this depends on your situation. If your computer is thawed you can simply use Regedit. If your computer is frozen or if it doesn't boot you'll need to find another way. Here are some alternatives:
 - If you have a multiboot computer with another copy of Windows 2K/XP you can boot from there.
 - You can physically mount the disk on another computer that uses Windows 2K/XP.
 - You can use a tool that lets you boot and edit the registry. A good example of this is PE Builder that lets you build a Windows PE CD and boot Windows from there.
Windows XP can import and edit the system hive from Windows 2K (hive format 1.3) but Windows 2K can't import the system hive from Windows XP (hive format 1.5).
2. If your computer is thawed run Regedit. If it's not thawed follow one of the alternatives described above, run Regedit (or Regedt32 on Windows 2K) and import the system hive. To import the hive highlight HKEY_LOCAL_MACHINE. On the menu go to File or Registry, Load Hive and open the system hive from the control, that should be on %windir%\system32\config (from the disk where DF is installed).
3. A dialog box will open and you will be prompted to enter a name for the key where the hive will be loaded. We'll use MySystem. If you are using Windows 2K, after loading the hive close Regedt32 and run Regedit.
4. Highlight the new key HKLM\MySystem (or HKLM\SYSTEM if you didn't have to import the hive) and select Edit and Find from the menu.
5. On the Find dialog box type UpperFilters and check only the Values checkbox. Then click Find Next.
6. The program will find a value with the name UpperFilters. Open this value and if there's a line with the name of the Deep Freeze driver (DeepFrz or DepFrzLo) delete it including the return, leaving the rest of the lines intact. Also, if you are using ThawSpace and you want to get rid of it delete that line too (ThwSpace), if you want to keep the ThawSpace leave it there. Press F3 to find the next match and repeat the operation until you have fixed all the UpperFilters values inside the HKLM\MySystem key.
7. Navigate to HKLM\MySystem\Select and check the value with the name Default. It has the number of the control set key that the system will use when booted. If it is 1 the control set is ControlSet001, if it is 2 the control set is ControlSet002, and so on. We'll assume the control set is ControlSet001 but you should use the one specified by the value Default.
8. Now go to HKLM\MySystem\ControlSet001\Services and delete the keys with the name of the Deep Freeze drivers (DeepFrz or DepFrzLo and DepFrzHi). Also, if you decided to get rid of the ThawSpace delete the key with the name of the ThawSpace driver (ThwSpace).
9. That's it. Now reboot and load the system where Deep Freeze was installed and you'll notice you can make permanent changes to disks that where previously frozen.
Stat rosa pristina nomine, nomina nuda tenemus.
Copyright (c) 2005 by Emiliano Scavuzzo - All Rights Reserved


text:
Felix began planting trees in the late 1990s, and has since cemented his passion for British forestry by setting up The Heart of England Forest Limited charity, dedicated to planting a substantial native broadleaf forest in Warwickshire. Felix often makes a personal donation to the charity and between his personal country estate and The Heart of England Forest, over 1,874 acres of woodland have now been planted. Planting proceeds at the rate of approximately 300 acres per year. In the summer of 2013, the Forest hit a major mile-stone which was the 1 millionth tree. By the end of the planting season in March 2014, another 100,000 were planted.
Each year we plant in the region of 100 hectares of new woodland comprised of native broadleaved trees. We structure the species mix to mimic the local dominant woodland type as set out by the National Vegetation Communities (NVC) woodland classifications, which are W8 or W10 for our area. Both are lowland broadleaved woodlands with ash or oak the dominant species respectively. These woodland types refer to mature woodland and include ground flora as part of the classification description. We cannot, of course, create all aspects of a mature woodland but aim to plant the major and minor tree species in suitable proportions to kick start the process and allow the woodlands to develop naturally and take on a character of their own.
Major tree species for our area are; English oak and ash. Minor tree species include; sessile oak, birch, small leaved lime, field maple, cherry, hornbeam, aspen, sweet chestnut, rowan, whitebeam and willows.
Our woodlands are designed with a high proportion of open space in the form of wide rides between woodland blocks. These rides are typically 10 to 15 metres wide with additional more open areas up to 50 metres across. Wild flower meadow species have been sown in the open areas to increase diversity and aesthetic quality.
The trees are planted at a density of 1080 per hectare in a random pattern between 1 and 6 metres apart. We do not plant large groups of single species except for coppice areas. However, where the ground is wet or free draining we plant a higher proportion of tree suited to that particular ground condition.
We use trees grown from local provenance seed sources but also collect and grow on our own seed from the estate. The trees are planted as bare root whips up to 60cm high usually about two years old.
Our planting season starts in mid November and continues until the following March.
Trees are protected from rabbit and deer damage by either 1.2 metre plastic tubes or 75cm plastic spirals, the latter is also further protected by a 1.8 metre high fenced perimeter to exclude deer.
We maintain the trees annually and more intensively in the first few years. Work includes maintaining a weed free area around each tree, loss assessment and replacement of trees where necessary and straightening of trees guards where they have blown over in the wind. We also regularly inspect for the detrimental effects to trees from deer, rabbits, hares, voles, insects and noxious weeds. Where we can have an influence we do take measures of control.
Following the first few years where possible we remove guards. This more commonly occurs to the faster growing trees such as aspen, willow, cherry and birch.
The management of the open space is less intensive and currently involves mowing the rides to create 3 metre wide tracks twice a year – early July and Octoberand where possible we cut and remove the vegetation from the wider open space. The removal of the cut material will gradually lower the nutrient levels of the soil making it more suitable to wild flower species.
We welcome natural regeneration of trees within our woodlands and respond positively where it occurs. A hedgerow tree is the usual seed source and nearly always happens near ash trees, field maple and to a lesser extent around oak. Oak regeneration is unusual in that it can occur just about anywhere in the woodland, probably dropped or buried by corvids (jays, crows, magpies, etc) or squirrels.
For further information about the Heart of England Forest, please visit: _URL_


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If you, your senior parents, or anyone else in your family is thinking about weight loss as a New Year's resolution, watch and listen to this short National Library of Medicine (NLM) video that explains how newly published research in the journal Preventive Medicine has found an inverse association between the number of miles a person drives and weight loss.
An inverse association means that amount of weight loss increases as the miles a person drives decreases.
The NLM page with the video also includes a transcript. It's also possible to click on the "CC" symbol at the bottom right of the video and turn on captioning.
Check out the abstract of the article, Quantifying the Association Between Obesity, Automobile Travel, and Caloric Intake. The full article is not free, but may be available at a public library and definitely at a hospital library. You can read a bit more about the research in a U.S. News Health article.


Nutrition: Group Education
Background on Group Education
guy with fruit
expandWhat are group education strategies?
collapseWhat are group education strategies?
 - Through group education interventions, trained nutrition instructors or facilitators (e.g., dietitians, health educators) provide information and resources as part of group interactions to increase knowledge, skills and support related to increasing consumption of nutritious foods.
 - Group education interventions may include presentations as well as individual or group activities that occur in classrooms (e.g., schools, colleges or universities), community centers, WIC clinics, recreational facilities, worksites and other desired locations. Guided by a detailed nutrition curriculum, these interventions can:
 - highlight the association between what we eat and health outcomes (e.g., fat intake and obesity),
 - promote behavioral change (e.g., purchase foods with less sugar; eat more fruits and vegetables),
 - improve knowledge and skills related to the benefits of nutritious foods (e.g., increased energy, weight loss) and challenges with making lifestyle changes (e.g., skill-building for healthy food preparation), and
 - influence social support or group norms (e.g., sharing recipes or strategies for overcoming challenges).
expandHow does group education impact nutrition-related behaviors?
collapseHow does group education impact nutrition-related behaviors?
 - For many individuals, the group is a natural setting. People are often taught in groups, live in groups and play in groups. Social interaction can be a key aspect of the developmental process as individuals learn by observing others and the results of their actions. Therefore, group education interventions can be most effective if they take into consideration both individual characteristics (e.g., knowledge, skills) and group circumstances (e.g., social norms, peer pressure). For example, it may be more helpful to have different group members talk about how eating more nutritious foods and establishing healthy eating patterns has helped them feel better physically and mentally, as opposed to simply describing the relationship between nutrition and health.
expandHow can I use group education strategies in my nutrition intervention?
collapseHow can I use group education strategies in my nutrition intervention?
 - Group education interventions may be incorporated into existing education interventions (e.g., health education classes in schools, cooking classes at a local grocery store) or held independently.
 - Group education can be designed to meet the needs of general audiences or specific groups (e.g., "targeted messages"). For example, the group education interventions can address the special needs of populations with particular health concerns (e.g., diabetes, cardiovascular disease), adolescent girls (e.g., basic identity questions, peer pressure), or those who prepare foods for others (e.g., school cafeteria staff).
expandWhat type of group education is best for my nutrition intervention?
collapseWhat type of group education is best for my nutrition intervention?
 - Groups set up primarily for prevention (i.e., education or skills training to encourage nutritious eating patterns such as reducing consumption of fat, sugar, or sodium and increasing consumption of fruits, vegetables, or fiber in order to minimize risk of disease and disability).
 - Groups concerned with specific health conditions and their improvement (i.e., education or skills training to help individuals with various health conditions such as obesity, arthritis, heart disease, or diabetes to lose or maintain weight, balance important nutrients, or avoid specific types of foods).
 - Groups related to general life adjustments, self-management, and lifestyle (i.e., education or skills training to increase individual's capacity to consume nutritious foods as part of daily or weekly routines such as minimizing fast food intake, providing fruit and vegetable snacks, preparing foods with nutritious ingredients, or reducing portion sizes).
 - Groups with other quality of life concerns such as improved appearance (e.g., weight, acne), increased athletic performance (e.g., training for a marathon), or spiritual beliefs (e.g., connection between physical, mental and spiritual health).
expandWith whom do I need to work to develop a group education strategy for my nutrition intervention?
 - To develop your group education intervention, you will need to work with experienced health educators. Other useful partners may include senior centers/independent living facilities, community centers, community organizations, coalitions, schools, worksites, health departments, researchers, community members, and community leaders.
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SET ANSI Command
Specifies whether to pad a shorter string with spaces when making a SQL string comparison or binary expression with zero (0) bytes when making a binary expression comparison in SQL commands using the equal sign operator (=).
In the Visual FoxPro OLE DB Provider, you cannot query the value of ANSI using the SET command though SET ANSI is supported.
Pads the shorter string or binary expression with spaces or zero (0) bytes needed, respectively, to make it equal to the length of the longer string or expression. When SET ANSI is set to ON, the two strings or expressions are compared character for character for their entire lengths.
Specifies that the shorter string not be padded with spaces or binary expression not be padded with zero (0) bytes. (Default)
When SET ANSI is set to OFF, the two strings are compared character for character until the end of the shorter string is reached.
SET ANSI has no effect on the double equal sign (==) operator. When you use the == operator, the shorter string or binary expression is always padded with spaces or zero (0) bytes, respectively, for the comparison. For more information, see Relational Operators.
SET ANSI is scoped to the current data session.
SET ANSI and the Query Designer Visual FoxPro builds a SELECT - SQL command in the Query Designer when you create a query. When creating Join and Filter conditions, if you choose the Equal or Exactly Like options, the = or == operator is included in the generated SELECT. The SET ANSI setting can affect the results of queries you create and perform in the Query Designer.
String Order In SQL commands, the left-to-right order of the two strings in a comparison is irrelevant — switching a string from one side of the = or == operator to the other doesn't affect the result of the comparison.
The following example creates a cursor with one record and then demonstrates how SET ANSI affects query results. When SET ANSI is set to OFF, the result is one because the strings are compared based on the shortest. 'Tommy' becomes 'Tom', and the strings 'Tom' and 'Tom' do match character for character.
When SET ANSI is set to ON, the result is zero because the strings are compared based on the shortest padded with spaces. 'Tom' becomes 'Tom ', and the strings 'Tom'and 'Tommy' do not match character for character:
CLEAR CREATE CURSOR Dummy (name c(10)) INSERT INTO Dummy VALUES ("Tommy") SET ANSI OFF SELECT * FROM Dummy WHERE name="Tom" INTO CURSOR result?"With ANSI",SET("Ansi"),_tally && shows 1 SET ANSI ON SELECT * FROM Dummy WHERE name="Tom" INTO CURSOR result?"With ANSI",SET("Ansi"),_tally && shows 0


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OBJECTIVES: To determine the association between the ability of a different strains of meningococci to survive in whole blood and the age of the donor. METHODS: A panel of serogroup B and a serogroup C strain of Neisseria meningitidis was tested in an ex vivo whole blood model. Blood from 81 healthy children and 20 adults and from children during convalescence from serogroup B (55 patients) or serogroup C (43 patients) meningococcal infection was assessed. RESULTS: Age-dependent acquisition of whole blood killing of serogroup B and C bacterial isolates was demonstrated in healthy children with an inverse relationship to the reported incidence of disease. After infection with serogroup B or C meningococci, evidence of whole blood killing of the bacteria was found even in blood from children <2 years of age, the survival of a serogroup B strain, MC58, being reduced compared with that in healthy children (median, 64% compared with 194.5% survival at 90 min). In both affected children and controls, there was a significant correlation between whole blood killing of strain MC58 and of other serogroup B and C meningococci. CONCLUSIONS: The whole blood model measures both humoral and cellular mechanisms responsible for the bactericidal activity of blood. The model was first described 80 years ago, but this is the first description of its age dependency. Acquisition of bactericidal activity was more rapid in children infected and is directed at various strains of meningococci, indicating the presence of a cross-reactive antigen(s).
Original publication
Journal article
Pediatr Infect Dis J
Publication Date
868 - 873
Adolescent, Adult, Age Factors, Antibodies, Bacterial, Blood Bactericidal Activity, Carrier State, Case-Control Studies, Child, Child, Preschool, Cross Reactions, Female, Humans, Infant, Infant, Newborn, Male, Meningococcal Infections, Neisseria meningitidis, Reference Values, Risk Assessment, Serotyping, Serum Bactericidal Test, Statistics, Nonparametric, Time Factors


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Benefits of Prenatal Care For Buy abortion pills in UAE
Pregnancy can be an exciting time. But this requires some responsibility. For example, you need to take steps to stay healthy with your child. In fact, maintaining a healthy pregnancy is one of the best ways to ensure Buy abortion pills in UAE healthy birth. So it's important to keep in touch with each other as soon as you decide to have a baby or as soon as you get pregnant.
A prenatal visit to an OB / GYN doctor usually includes a physical examination, urine analysis, and weight management. Depending on the stage of pregnancy, you may need imaging tests such as ultrasounds and even blood tests. Below is an overview of some of the benefits of proper obstetric care.
Reduce the risk of To Buy Abortion Pills in UAE
Choosing a healthy lifestyle during pregnancy can significantly improve your fetal health and help Buy abortion pills in UAE complications. By working closely with your obstetrician/gynecologist, you can learn more about what foods you should eat and what best exercises to do. You can also set your own weight. The key is to have regular check-ups for diseases such as high blood pressure and gestational diabetes and to make sure these conditions are under control to protect you from possible pregnancy complications.
Reduce the risk of complications for the embryo or fetus
Both alcohol and smoking have been shown to increase the risk of sudden childhood syndrome. Alcohol consumption can also increase the risk of fetal alcohol spectral impairment, which can lead to problems such as abnormal manifestations, poor memory, poor coordination, cognitive impairment, and problems with organs such as the heart, bones, and kidneys.
Studies have shown that babies can have long-term problems during pregnancy, even with small amounts of alcohol. During prenatal visits, you will learn about the dangers of these toxins and why it is important to avoid them. If you are trying with quitting alcohol or smoking, your doctor will advise you on programs that will help you in the future.
In addition to avoiding toxicities, your doctor will prescribe appropriate medications. For example, 400 grams of folic acid and other vitamins can significantly reduce the risk of stroke.
Make sure the medications you take are safe
It is wise to use over-the-counter medications during pregnancy. You may even need to stock up on prescriptions. In other words, seeing an obstetrician/gynecologist during pregnancy will protect you from taking dangerous medications.
To Take Directions
In general, it is clear that the importance of reproduction cannot be overstated. In fact, the quality of prenatal care has a huge impact on a woman's health and the health of her baby. So if you want to buy abortion pills in UAE pregnant or are already pregnant.
Do not claim to be sterile until you have tried these tips to help you get pregnant. Any woman can get pregnant, and if the doctor says everything is fine, you are pregnant. All you have to do is practice all the healthy habits and make yourself happy. Eat well, take vitamins, avoid solid foods, maintain your weight, and stay close when you have other children. Don't overdo it so that everything shakes when the time is right.


Using IR modules from VCRs
1) Intro
Some time ago, I came across the Lirc (Linux Infrared Remote Control) website and decided to build a serial port IR receiver. They had a list of suggested IR receiver modules, but I was unable to buy one, so I had to think of using something else.
A IR Receiver module is usually a photodiode and a 38khz detector. Most of them have 3 pins. VCC, GND, an output pin. If a 38khz carrier is detected, the output pin will become active. Some modules are active low, and others are active high. It is sometimes required to use an inverter(eg: 7404) to get the correct signal.
At first I thought to build a 38khz detector and to use a photodiode for receiving IR, but I soon realized that this would be too much trouble. Instead, I decided to use the IR module from one of my old VHS I had lying around.
2) Finding the module inside the VCR
This should be pretty easy. Just remove the plastic cover from the front panel, and you will probably see a small metal cage somewhere, as shown in the picture to the left.
3) Figuring out the pinout
There are 2 types of modules used in VCRs:
 1. Self-contained modules
 2. Built on board modules
1. Self-contained modules
Self contained modules are usually come with their metal cage soldered to the PCB, with 3 wires or pins coming out. Here are pictures of such modules:
The pinout is not usually too difficult to guess. If you're lucky, it will be printed on the pcb like this:
Otherwise, you can find the pinout by trial and error. Simply connect the ground, vcc. Connect the output pin to a led using a high resistor value like 1k. Also, limit the current in the VCC line if possible(using a resistor or a good power supply).
To test your pinout, aim a remote control to your module and press a button. The led will blink if you have the right pinout.
2. Built on board modules
Built on board modules have their metal cage soldered to the PCB, and a bunch of component (sensor, chips, resistor, caps...) directly soldered to the PCB. If you have this type of module, I recommend that you cut the PCB around it using a dremel or something.
Next, look at the board layout. Usually, this area is insulated with a ground plane. You will probably see 3 traces going inside the module like this:
One of them is VCC, another GND, and the last one is the output. You can easily guess which one is the ground and vcc. Just follow them on the PCB, and it will eventually connect to other chips. You can look theese chips datasheet to learn their pinout. If the trace connects to a VCC or GND pin, you got it. The remaining trace is the output.
4) Using the module
You can use these modules as an universal infrared receiver for your computer with projects like Lirc. You build an Infrared Break Beam detector. You can extend the range of your remote controls by building a repeater.
Written by Raphaël Assénat <>, in the hope that it will be useful. Comments and suggestions are welcome.
Sun Sep 29 15:29:17 EDT 2002


Why Call It 'Performance Capture'?
Why Call It 'Performance Capture'?
Just because a director or computer animator can change a performance digitally, doesn't mean the work didn't originate from a uniquely valuable place.
Motion capture is one of the more rigorous performance types because in addition to requiring the full range of human emotion, a performance capture artist may have to learn fighting or dance skills, not to mention the physicality that goes along with simply wearing "the suit."
Add to that the challenges of reacting, and hitting your marks, when your only references may be a green screen and a monitor, and you can see why this type of work is special.
So much so that SAG recently created a Performance Capture Committee, which will begin raising awareness of Screen Actors Guild's contributions to the art in the coming months. Stay tuned.


Pascali's Island Test | Final Test - Easy
Buy the Pascali's Island Lesson Plans
Name: _________________________ Period: ___________________
Multiple Choice Questions
1. How much does Izzet then offer?
(a) 700 liras, which is what Bowles initially asks for.
(b) 800 liras.
(c) Nothing.
(d) 600 lira, 50 of which will pay Bowles for his time already spent.
2. What does Pascali figure out about how Bowles will remove the statue from the island?
(a) He's still trying to figure it out.
(b) By way of Smith's boat.
(c) Through the mountains over to the other side of the island.
(d) By ballon in the middle of the night.
3. What does Bowles insist that he is doing?
(a) Helping the field of archeology.
(b) Being honest.
(c) Writing a book.
(d) Paying Pascali.
4. When Pascali tells Bowles Pasha wants to kill Bowles, what is Bowles' response?
(a) That Bowles feels safe.
(b) That Scotland Yard is keeping an eye on things.
(c) That Bowles has a few tricks up his sleeve.
(d) That Bowles is leaving that night.
5. Why does Bowles want to leave the situation for a few days?
(a) To find out who is behind Pasha's scheme.
(b) To extort more money.
(c) Because he has not finished his research.
(d) To find more artifacts.
6. What does Izzet say he knows about Bowles?
(a) That Bowles used to work for Scotland Yard.
(b) That Bowles and Smith are associated.
(c) That Bowles does have an advance degree in archeology.
(d) That Bowles has a wife arriving on the next boat.
7. Of what does Pascali write to the Sultan again?
(a) The need for more money.
(b) The suspicians he has of Bowles.
(c) The fear he has that he has been discovered.
(d) Pascali's blending of reality and illusion to create realism in imaginary settings.
8. What happens as Pascali waits at the hotel?
(a) Bowles does not show up.
(b) Bowles arrives but will not speak to Pascali.
(c) Pascali witnesses a handoff of a large package from Bowles to Smith.
(d) Pascali gets drunk.
9. What does Pascali insist to Bowles about the church service?
(a) That they were going to kill Pascali.
(b) That the Saint was hexed.
(c) Pascali is unwilling to answer Bowles's questions.
(d) That the priest is in on the conspiracy to kill Bowles.
10. What shocking news does Bowles give Pascali?
(a) That Lydia is actually a German government agent.
(b) That the Sultan is dead.
(c) That Germany has occupied Constantinople.
(d) That the Sultan is on his way to being deposed.
11. How does Pascali see Bowles?
(a) As a brilliant archeologist.
(b) As a dreamer and both a victim of his own mind and an exploiter of those ideas.
(c) As a dead man.
(d) As a frustrated writer.
12. What does Bowles' notebook indicate?
(a) That Bowles actually is a geologist.
(b) That Bowles is cousin to the Sultan.
(c) Bowles has completed this same scheme that he is running on Pasha in numerous areas around Asia Minor for many months.
(d) That Bowles works for German SSI.
13. What goes wrong with the meeting?
(a) Izzet does not show.
(b) Bowles does not show.
(c) Bowles brings English soldiers.
(d) Pascali is not there to translate.
14. Why does Bowles want a few more days at the site?
(a) To make his getaway on Smith's boat.
(b) To hide his activities.
(c) To plunder the artifacts more.
(d) To make a few more sketches.
15. What does Pascali know about Izzet and Pasha regarding payment?
(a) They do not know they are being blackmailed.
(b) They do not care if they lose such a small sum of money.
(c) They have no choice but to pay the 700 lira that Bowles demands.
(d) They do not have that much money.
Short Answer Questions
1. How does Pascali close his report?
2. What does Pascali realize that Bowles believes about himself?
3. What does Pascali see as he's walking home through the market?
4. To what does Pascali admit?
5. For what purpose would he do the answer to question #97?
(see the answer keys)
This section contains 725 words
(approx. 3 pages at 300 words per page)
Buy the Pascali's Island Lesson Plans
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When changing a (small) part of the plaintext of a CBC-encrypted file, how much of the file will have to be rewritten?
My suspicion is that everything after the modified block will have to be decrypted and reencrypted as well, due to the changes of the ciphertext blocks cascading through the rest of the file.
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2 Answers 2
up vote 7 down vote accepted
If you could use the same IV, then yes, you would need to rewrite everything after the modified block.
But you shouldn't do that; every time the contents change, you should generate a new IV, which would require the whole file to be rewritten. Otherwise an attacker can learn more information than it should about how the file changed (precisely by checking which blocks of the file have changed).
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As _USER_ stated this should not be done as it leaks some information that can be used by an attacker in order to make some statistical analysis. According to theory this is the diffusion property that a cryptosystems must hold: One bit flipping in the plaintext must change as much as possible the the bits on the ciphertext. The linear parts of a block cipher as AES achieve this.
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By Past RI Vice President Serge Gouteyron, member of the Rotary Club of Valenciennes-Denain aerodrome (France) and Chair of the 2015-16 RI Rotary Fellowships Committee
The second Object of Rotary encourages Rotarians to hold high ethical standards in business and profession; to recognize the worthiness of all useful occupations; and to dignify each Rotarian's occupation as an opportunity to serve society. Through Rotary, members from different professional and cultural backgrounds are able to combine their expertise and experiences to create a greater impact. By connecting with fellow Rotarians who share a common profession or hobby, Rotary Fellowships contribute to the promotion and advancement of Rotary worldwide. Fellowships enable Rotarians to bond with those outside of their club, district, or country. Vocationally oriented fellowships allow Rotarians to use their unique skill sets to serve their community and further their professional development while building lasting friendships.
How can we increase our impact through Fellowships?
Dear friends, let's extend our spirit of friendship and service spirit beyond our clubs and let's further mutual understanding through Rotary Fellowships. We invite Rotarians whose profession is not represented among the current fellowships to create one. Vocationally-based fellowships based are quite significant as they embody the historical identity of Rotary and of its values.
The following stories will inspire you to join an existing group or start a new one:
- Passion for the friendly skies fosters international service partnerships
- Medical myths inspire fellowship and service
- Rotary Fellowships: service inspired by passion
- Rotary Fellowships' annual activities support polio eradication efforts
Starting a fellowship requires a roster of potential members representing at least three countries and approval from the RI Board of Directors. Find more information online: _URL_


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2. POSITIONING TOWARDS CUSTOMER AND SUPPLIER
2.1. Traditional commerce vs E-commerce
Multiple media vs a single one
towards traditional commerce or e-commerce affects directly its processes and strategy. The main difference between exercising traditional commerce and e-commerce is that in the former
(like magazines, letters, mail, fax, etc) are used while in the latter
everything is digital.
Traditional commerce means
(ordering, paying) with customer and supplier using different applications in
many time-consuming different steps
E-commerce means processing of information using
one digital application
(EDI or Internet) and only
a few quick steps
Positioning is a plan showing the
of the company towards other actors of the market.
Interactivity characterises a system when it is in a
steady dynamic process of data interchange between many equal and free access system users at the same time.


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The baseline temperature in an electronic system is a very important parameter for thermal design and must be carefully considered. But the term ambient temperature has developed a lot of ambiguity in its usage as well as its value. System and component designers can greatly improve the accuracy of their thermal considerations by clearly communicating what the baseline temperature truly is for their implementation, and finding a way to estimate the temperatures at or close to the components of interest.
What is Ambient Temperature?
Thermal analysis is an essential part of nearly all electronic system designs these days. We have to make sure that the components do not heat up so much as to affect their functionality or make the system practically unusable. And for most of us, it's a delicate dance of environmental factors, system design, component power dissipation, and a range of usage conditions. We must establish some baseline temperature conditions, then figure out through modeling, calculations, rules of thumb, and ultimately measurements – how much will things heat up above that temperature.
So what if that baseline temperature and the assumptions around it could vary so wildly, that all the other calculations are rendered as noise, and the results of such a calculation could be off by 100 percent or more? In other words, what is ambient temperature?
The interesting thing is that while it is a very common term, there seem to be different assumptions on what "ambient temperature" really means. Here are some interpretations used by some of us day in and day out, as also illustrated in Figure 1:
- The temperature of the system, unaffected by the temperature rise of the system itself (either far enough away or before the system is turned on). The equivalent of a true thermal ground.
- The temperature of the air inside the system when it is running. Often measured far away from the component of interest so as not to be too much affected by it.
- The temperature of the air moving over a component.
- The temperature of the board or chassis of the system, which is considered to never rise above a certain maximum temperature.
- The temperature of the air (usually driven by fans) at the entry or exit of the system.
- The temperature of the room when a component or system is tested on the bench, on an evaluation module (EVM) or a real system board (with or without an enclosure).
- The temperature setting of the oven when a component or system is tested at high temperature (with or without an enclosure).
- The temperature to which a system is preheated for an operational test (of unspecified duration).
Figure 1: Eight potentially different ambient measurement points.
(Click on image to enlarge)
For example, an end system designer will probably use 2, 4, or 5, because this is the temperature they have experience with from previous systems and will ultimately be able to measure on the system in the field. While a system test engineer will probably use 6, 7, or 8, since they need to focus on the temperature they can control during testing. Alternatively, a component supplier will probably use 1 or 3, since these are conducive to component modeling and the component suppliers are generally not privy to the level of detail needed to consider the entire system effects.
There are two common misconceptions when using ambient temperature alone for calculations of component temperatures.
The first is that each component can be viewed in isolation. You simply go to the datasheet for the component of interest, get the theta-JA value (or maybe even a fancy table or curve or derating factor), drop in your ambient temperature and power dissipation, and there is your component temperature.
But this calculation assumes only one component on the board, and that it therefore has the entire board (or at least a 3x3 inch square of it, if using a JEDEC board) dedicated to cooling it. I've not seen many systems where this is the case. In reality the other components around that one will be heating it up and skewing that calculation.
The second is that the ambient in one system is equivalent to the ambient in another. Specifically, that the ambient in a JEDEC system, a one cubic foot box with only one component inside, is equivalent to the ambient in a real system such as a cell phone, base station, or even a car.
Looking at the comparison in Figure 2, it's pretty clear that this is not what real systems look like, and yet that is the implicit assumption when a JEDEC theta-JA (ΘJA) value is used to calculate component temperature rise above ambient. In fact, the very definition of theta-JA (JEDEC standard JESD51-2) states that the parameter is intended for comparison only!
Figure 2: System comparison.
(Click on image to enlarge)
If ambient temperature means different things to different people, and the basic calculation of component temperature rise above ambient temperature has some flaws in it, what is a system or component designer to do? Here are three suggestions.
First: agree on terms when working through the design stages. Don't accept a simple specification of (for example) 65°C ambient temperature or industrial temperature rating, but dig into such details as where is the baseline temperature measured, under what operation conditions, and for what period of time?
Second: find a way to get closer to the components than the ambient. This will make the estimates much more accurate, because of the implications of each system's uniqueness as well as the surrounding components. One good method is to use the board or case temperature as the reference specification, rather than ambient.
Third: take case temperature measurements on the actual system to confirm the analysis. A good way to bring these data earlier into the design cycle is to use measured data on similar systems (often a previous generation) to get an estimate and calibrate, and then simply consider the changes rather than doing thermal analysis of a new system from scratch.
So ultimately, what is ambient temperature? It is a commonly used term. It carries the risk of ambiguity because it is not clearly defined. It carries the risk of inaccuracy because it suggests that junction temperature calculations can be oversimplified. When carefully defined, it can help to start the conversation on thermal design. But, ultimately, it is probably not the best place to end the conversation because there are better options available.
Download a datasheet: "IC Package Thermal Metrics", Darvin Edwards, Texas Instruments, SPRA953A–June 2007: _URL_
About the Author
Matthew Romig currently serves as the Packaging Technology Productization Manager in the Analog organization at Texas Instruments, where he is responsible for packaging technology development and implementation for TI's broad range of Analog product lines and packaging technologies. He has developed specialties in thermal analysis, flip chip packaging, and power management packaging. He is also a member of TI's Group Technical Staff. Matt received his BSME from Iowa State University, Ames, Iowa. He can be reached at _EMAIL_.


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Uses of Author Interviews for Art Educators & Students
Show professional illustrators demonstrating art techniques and mediums,
for example …
Watch professional illustrators teach the book-making process,
for example …
What is an Author Interview?
- Author Interviews are interviews with authors and illustrators in video, audio, and written formats.
- Meet-the-Author Programs are filmed by TeachingBooks.net in the homes and studios of award-winning authors and illustrators to enable readers to connect with the author the moment they are studying a book.
Authors talk about:
- Working with ideas
- Doing research
- Bringing history to life
- Being a professional author
- Diverse art techniques
- Approaches to book design
- Illustrating fiction and nonfiction
- Being a professional illustrator
Share how you use Author Interviews as an art educator.*
Here are some curricular uses submitted by educators…
- "I share Author Interviews because they give physical descriptions on how the art was used."
- "I use the Author Interviews to have the author explaining, in their own words, how a technique is used—or how the process of creating an illustrated book is done."
- "I use Author Interviews to show art techniques to students, as well as expose them to professions in art education. This brings art and literacy together."
- "After watching an Author Interview, break students break into teams of 4 to come up with some specific questions they would like to ask the illustrator if he or she were a guest in the classroom.
Also, use Author interviews to inspire students and help them to become more excited about making their own work—especially when creating'minibooks' in the art room."
- "I use Author Interviews to share with the students information that brings history to life, tips on doing research, and ways to approach writing/illustrating."
- "These author/illustrator programs are inspirational for me, exposing me to different techniques that I might use with the class. I also show the videos to my students to inspire them to 'think outside the box.' In particular, I liked Denise Fleming's reinforcement that the use of'sound words' such as "Crunch, Munch" are particularly effective in story writing."


text: Tic-Tac-Toe is a Design Studies tutorial that explores strategies and methods of approaching and revealing design thinking. Over one semester we explore 9 propositions that form alternatives to the status quo and offer ways to challenge design strategy. These tactics are a random selection of 9 – yet they offer a discourse on how we might interrogate the ideas we assume are critical to the essence of design action: The 9 tactics explored Generosity, Empathy, ReUse, Repair, Culturing, Play, Futuring, Co-working, and finally Making. At the end of 12 weeks each participant proposed a tactic that offered an alternative to an already understood design thinking practice. This reveals how this might be demonstrated in a project.This a a compilation of propositional design tactics proposed by the participants of the Tic-Tac-Toe, design Studies Tutorial.


text:
VW Strain Gauge Q&A
Question: What checks can I perform on VW strain gauges.?
Answer: You can perform standard wire checks as follows:
1. Read the device with the appropriate VW indicator and check its frequency of oscillation against expectations. Note that some gauges will not perform unless they are welded to a surface.
2. Read the temperature device embedded in the unit which should typically yield a reading within a couple of degrees centigrade. Most VW sensors now have a thermistor.
3. Check for short circuits between cable leads and the metallic body on the gauge, and between circuits per the table below. This can be done with a digital multi-meter with ohms range of 20 megaohm. Do not use a high-voltage megger device as this can damage the gauge by breaking down insulation.
Question: How can I convert Hz readings of the spot-weldable strain gauge to microstrain?
Answer: This is covered in the manual for our spot-weldable strain gauge. You'll need acrobat reader to view or print this manual. You can also use the formula below:
microstrain value = 0._PHONE_ x SQ(Reading in Hz) + (-2030.1)
Note that these numbers work only with the VW spot-weldable strain gauge. They are not suitable for the arc-weldable or embedment strain gauges.
Question: For some time, our technician was recording readings from the VW spot-weldable strain gauge using the VWP Indicator's "microstrainVS" setting (rather than the correct "microstrainVW" setting. How can I convert these VS readings to the correct microstrainVW readings?
Answer: The data can be converted without too much difficulty. The main
problem is that the VS readings used a
Hz = SQRT(711.09 * VS + 6783) - 82.4 (where VS is the microstrainVS reading)
Then, to convert the result to the correct microstrainVW reading, use the formula below:
uStrain = (Hz^2 / 1320) - 2030.1
For your convenience, we've made an Excell worksheet that provides these equations. The file is called VS2VWmicrostrain. Note that is equation is just for use with the VWP Indicator. You'll need an UnZip utility to access the file.
Question: I am not using a Slope Indicator readout. How can a obtain a reading in degrees C from the RTD used in your sensors?
Answer: Our published instructions assume that users are reading these 2K ohm RTDs using Slope Indicator readouts or the Campbell Scientific CR10X with AVW1 or AVW100 vibrating wire interface. These instructions will not work with other devices.
If you are using another device, obtain a reading in K ohms. Then apply either
of the following polynomial coefficients to obtain degrees C:
Solution A: For a range of -10 to +30 C.
Ax2 + Bx + C, where
Ax5 + Bx4 + Cx3 + Dx2 + Ex + F
A = 0.95659


Why Size Matters: Feature Coding as Nystrom Sampling
TitleWhy Size Matters: Feature Coding as Nystrom Sampling
Publication TypeConference Paper
Year of Publication2013
AuthorsVinyals, O., Jia Y., & Darrell T.
Other Numbers3440
Recently, the computer vision and machine learning community has been in favor of feature extractionpipelines that rely on a coding step followed by a linear classifier, due to their overall simplicity,well understood properties of linear classifiers, and their computational efficiency. In this paper wepropose a novel view of this pipeline based on kernel methods and Nystr¨om sampling. In particular,we focus on the coding of a data point with a local representation based on a dictionary with fewerelements than the number of data points, and view it as an approximation to the actual functionthat would compute pair-wise similarity to all data points (often too many to compute in practice),followed by a Nystr¨om sampling step to select a subset of all data points.Furthermore, since bounds are known on the approximation power of Nystr¨om sampling as a functionof how many samples (i.e. dictionary size) we consider, we can derive bounds on the approximationof the exact (but expensive to compute) kernel matrix, and use it as a proxy to predictaccuracy as a function of the dictionary size, which has been observed to increase but also to saturateas we increase its size. This model may help explaining the positive effect of the codebook size[2, 7] and justifying the need to stack more layers (often referred to as deep learning), as flat modelsempirically saturate as we add more complexity.
Bibliographic Notes
Proceedings of International Conference on Learning Representations (ICLR 2013), Scottsdale, Arizona
Abbreviated Authors
O. Vinyals, Y. Jia, and T. Darrell
ICSI Research Group
ICSI Publication Type
Article in conference proceedings


text:
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The EU experiments with an innovative system that charges motorists according to driving patterns.
BRUSSELS, Belgium — Everyone knows that each kilometer you drive costs you money, in fuel and wear-and-tear on your car. But even in the European Union, where gas averages an excruciating $7.84 per gallon, it's relatively easy to avoid thinking about the expense in between the uncomfortable incidences of filling your tank or needing auto repairs.
But what if you could see the cost of driving in real time? Would it affect the roads people took, or the time of day they travel?
A new push in the EU to "internalize" the "external costs" of transportation may make the day-to-day – or literally "kilometer-to-kilometer -- price of driving a bit harder to ignore in the not-so-distant future. For some volunteers in Leuven, Belgium, that moment is now.
Officials in this university town about 30 kilometers east of Brussels are trying out a system that tracks people's driving patterns and charges them according to when, where and what they drive. The goal: to convince commuters to change their ways — or at least their routes and schedules.
Such real-time traffic-data could help improve lives. Drivers in Brussels give up an annual average of 65 hours sitting in traffic. In Paris, it's 70 hours. Those figures come from international traffic-analysis company Inrix, which advises drivers in the Belgian capital that they could halve their morning rush-hour trip if they traveled at a different time of day than 8 to 9 a.m.
From Thailand: Bangkok's radical answers to global warming
It's unclear at this early stage what kind of taxes may be linked to such a system and whether other fees might be lowered as incentive for reducing time in the car. IBM's manager for the project, Friedl Maertens, herself one of the volunteers, says the city will determine tax rates in the future. The current goal, Maertens explained, is more basic, to "measure if pricing is a tool to influence driving behavior."
Partnering with high-tech giants IBM and NXP Semi-conductors, the town equipped 35 volunteer testers with the device, which is similar to a GPS. After a couple months of establishing baseline behavior, the monitor will calculate theoretical fees for the trips, which authorities could then charge as a tax. "Leuven has a mobility strategy (which) determines where the government wants to have cars and where they do not like to have cars," Maertens said, "so there it will be a little bit more expensive."
The city hired research-analysis firm Transport & Mobility Leuven (TML) to create a suggested price map for charging different areas of the city. TML says in its study that if no action is taken, traffic jams in Belgium will double in size by the year 2020. The report suggests "travelers need to think how to transport themselves at minimal social costs instead of minimal private costs."
That kind of thinking would be welcomed by another test driver, Said El Khadraoui, who has just had the monitor device installed in his car. The 36-year-old Leuven native said while he's already conscientious about only driving when necessary, with the new all-seeing on-board unit, "for short distances, I might think of leaving the car at home and making use of the bike."
But most of El Khadraoui's commutes are not bike-able; he's been a member of the European Parliament for the last eight years so he's in Brussels much of the time. He serves on the Transport Committee and is always looking for ways to make transportation more sustainable and less damaging to the environment. El Khadraoui authored a report that received final approval from European member states in mid-September to allow EU governments to charge heavy trucks three to four cents per kilometer for their "external costs" such as noise and air pollution.
Related: The cost of global climate change
El Khadraoui would like to see such a system extended throughout the European Union to passenger vehicles as well, but admits public attitudes are far from ready to accept that. "It's not possible from day one – that's obvious," he said, "but I think by 2020 you will see a lot of changes in the way cities are approaching mobility problems and trying to solve them."
Patrick Pype, Director of European Affairs at NXP Semi-conductors, which led in the creation of the device, envisions many uses that could help bring drivers 'on board." Pype points out that it can work like a super-equipped GPS, showing where traffic is tied up and how to avoid it, or in the case of the potential charges-per-kilometer, what the cheapest route might be. "It's a combination of GPS, GSM [mobile phone] and security," Pype explained, pointing out it also carries the recently unveiled "E-call" button, a Europe-wide accident-alert system.
Incorporating more "value-added services," IBM's Maertens added, will help "make the whole solution more comfortable and integrated."
It remains to be seen how "comfortable" anyone is going to be with a system that comes attached to the word "tax" or "charges," and El Khadraoui admits that's a huge challenge for policymakers. "You need a mentality change and therefore first you need the technology," El Khadraoui said. "Then you need to explain the consequences and the benefits." He recognizes there would have to be some tangible offsets such as lowering other taxes, to make such a system publicly palatable.
El Khadraoui also expresses confidence that privacy protection would be addressed, empathizing that he himself would be uncomfortable with the idea of someone tracking his travel. NXP's Pype says those concerns have been taken into account on the technology side, in building the prototype device with a chip capable of encryption similar to a bank card's.
El Khadraoui says he thinks consumers will come around…eventually. "Now we are in the phase – and this will take some time – of explanation," he said, "of finding out what can we offer people. People need to understand it's good for them and if you cannot explain it, it will never happen."
From Japan: Power from the people
Unfortunately for IBM and NXP, sometimes even if you can explain it, it won't happen. Just over a year ago, the companies were commissioned to run the same kind of test in the Netherlands. The conclusions exceeded expectations on all sides. That led to projections that nationwide adoption of the system would provide a "58 percent reduction in delays caused by traffic jams; a 15 percent reduction in the total number of kilometers driven annually; a 10 percent reduction in CO2 emissions; a 6 percent increase in total passenger kilometers via public transportation and (m)ore than 50 percent of Dutch households will pay less than they do currently for the motor vehicle tax and vehicle purchase tax." Officials had proposed dropping those charges in lieu of the pay-per-use system.
The Dutch government enthusiastically welcomed the results and announced the system would be adopted throughout the country. But not long afterwards, that government fell and the new prime minister, Mark Rutte, decided he didn't want to take the heat for new taxes, so the whole plan crashed.
The city of Leuven will start taking a look at its options next year when the test data rolls in.


text:
Why is Machine Gun Preacher rated R?
Official MPAA Rating: Machine Gun Preacher is rated R for for violent content including disturbing images, language, some drug use and a scene of sexuality.
Violence: Frequent depictions of violence with guns, knives, land mines and other weapons include some gory details. A child steps on a land mine and his corpse is seen with missing legs. A large group of burned and smoldering children's corpses are piled in a heap. A man shoots an assassin who turns out to be a young child. Adult men are killed and wounded during battles. A fight and a severe stabbing incident occur after two men pick up a Native American hitchhiker. A man yells at his wife and child.
Sexual Content: A married couple is viewed from a distance while having sex in a car—no nudity is seen. Later this same couple begins sexual activities in their home (kissing and passionate embracing are shown). A woman discusses her career as a stripper.
Language: Over two-dozen sexual expletives are used along with other profanity, scatological slang, and crude anatomical terms. Names of deity are used as expletives.
Drugs/Alcohol: Characters drink frequently, sometimes to the point of drunkenness. Injected drug use is portrayed in a few scenes, including one where a character is shown shooting up while driving a car. Later in the film, an addicted character is "rescued" and the effects of drug use are shown from a negative perspective.


text:
Gas exchange system for extended in situ benthic chamber flux measurements under controlled oxygen conditions: First application - Sea bed methane emission measurements at Captain Arutyunov mud volcano
Limnol. Oceanogr. Methods 6:23-33 (2008) | DOI: 10.4319/lom.2008.6.23
ABSTRACT: Mass transfer rates of many gases, nutrients, and trace metals across the sediment water interface are dependent on environmental oxygen conditions. In this article, a novel gas exchange system for extended in situ flux and respiration measurements in benthic chambers under defined oxygen conditions is described. Integrated within a GEOMAR modular lander, the gas exchange system was used to perform in situ measurements of the total oxygen uptake and sea bed methane emission rates under constant oxygen conditions at Captain Arutyunov mud volcano (Gulf of Cadiz) in a water depth of 1320 m. During two separate lander deployments, the oxygen concentration within the benthic chambers was kept constant for 37 and 47 h, respectively. Under these conditions total oxygen uptake rate remained constant at 4.4 and 13.2 mmol m2 d1. Seabed methane emission was low, in the range 0 to 0.2 mmol m2 d1. The system is suited for prolonged (days) in situ flux determinations under natural background oxygen conditions and offers a wide range of experimental applications.


text:
Alexander Schreiner's Rules for Congregational Singing —
In the days of John Wesley (_PHONE_) the people had hymn books with words only. The music notation, usually handwritten, was only on the music rack of the organist. Wesley's rules for congregational singing are still valid today. They are interesting as well as instructive.
1. Learn the tune.
2. Sing the hymns as they are printed.
3. Sing all of the hymn. "If it is a cross to you, take it up and you will find a blessing."
4. Sing lustily and with a good courage.
5. Sing modestly; do not bawl.
6. Sing in time; do not run before nor stay behind.
7. Above all, sing spiritually. Have an eye to God in every word you sing. Aim at pleasing Him more than yourself or any other creature. In order to do this, attend strictly to the sense of what you sing and see that your heart is not carried away with the sound, but offered to God continually.


Statistics Dictionary
Select term:
T Score
The term t score has different meanings in different settings:
 - In introductory statistics, t score is often used synonomously with t statistic.
 - In psychometrics, a t score is a type of standard score computed by multiplying a z-score by 10 and adding 50.
 - In bone density tests, a t score compares bone mineral density to a reference mean.
Often, the meaning is clear from the context. In educational research, the psychometric definition generally applies. In papers on osteoporosis, the bone density definition is probably the intended definition.
Sometimes, though, the meaning is not clear. Some statistics texts use the term to mean "t statistic". Others use the psychometric definition.
To avoid confusion, the Stat Trek website avoids the term "t score". It uses "t statistic", instead.
See also: Student's t Distribution


text:
The Reading and Literacy Discovery Center (RLDC) is a program within the Communication Science Research Center that integrates neuroscience, genetics and behavioral research methods with evidence-based reading interventions to improve childhood literacy by identifying reading difficulties before they happen. Through ongoing research and collaborative partnerships with universities, community organizations, local schools, and parents, the RLDC aims to enable every child to discover reading as a path to learning.
The RLDC staff is made up of researchers, educators, pediatricians, speech pathologists and reading specialists. With a common focus on improving childhood literacy, the RLDC staff provides children and their families with a comprehensive approach to addressing reading difficulties and potential reading disorders by providing evaluations, resources and referrals.
Services provided by the RLDC include an informational website for educators, parents and clinicians that reviews scientific research of evidence-based literacy practices and interventions, comprehensive reading evaluations and targeted literacy interventions for struggling readers, educational training opportunities in early childhood literacy and response to intervention, and educational partnerships with local universities.


text:
Definitions for yardstickˈyɑrdˌstɪk
Random House Webster's College Dictionary
a stick a yard long, commonly marked with subdivisions, used for measuring.
Category: Weights and Measures
any standard of measurement:
Tests are not the only yardstick of academic achievement.
Origin of yardstick:
a measure or standard used for comparison
"on what kind of yardstick is he basing his judgment?"
yardstick, yard measure(noun)
a ruler or tape that is three feet long
Kernerman English Learner's Dictionary
a standard against which sth can be judged
The stock market is a yardstick for economic performance.
a flat stick used to measure a yard
***Measure it with a yardstick.
A measuring rod thirty-six inches long.
A standard to which other measurements or comparisons are judged.
a stick three feet, or a yard, in length, used as a measure of cloth, etc


text:
No for "dry", yes for "wet".
For "dry friction", such as a box on a floor, it is relatively constant. Why is this? Most objects are microscopically rough with "peaks" that move against each-other. As more pressing force is applied, the peaks deform more and the true contact area is increases proportionally. The surfaces adhere forming a bond that will take a certain amount of shear force to break. Since the molecules are moving much faster ~300m/s than the box they have plenty of time to adhere (so velocity is not an issue). However, static friction is sometimes be higher, in one explanation because the peaks have time to settle and interlock with each-other. Neglecting static friction, force is constant.
The simplest case in wet friction is two objects separated by a film of water. In this case there is zero static friction, as the thermal energy is sufficient to disrupt any static, shear-bearing water molecule structure. However, water molecules still push and pull on each-other, transferring momentum from the top to the bottom. The rate of momentum transfer i.e. "friction" grows in proportion to how much momentum is available, which in turn grows with velocity. Thus, force is linear with velocity.
However, interesting things happen when the bulk mass of the water gets important. In this case, bumps, etc on the surface push on the water creating currents that can ram into bumps on the other surface. If you double the velocity, your bumps will push twice as much water twice as fast for 4 times the force; force is quadratic to velocity. You can plug in formulas for the linear case (which depends on viscosity) and quadratic case (which depends on density) to see which one "wins" (this is roughly the Reynolds number), if there is no clear winner the answer is complex (see the Moody diagram).
Nevertheless these are approximations and the real answer could fail to follow these "rules".


Tag: mental imagery
Muscle Strength Is In The Mind: Just Imagining Arm Exercises Creates A Tangible Effect On The Body
Brain and brawn aren't mutually exclusive—that, in fact, they have more in common than they ever thought. In a small study recently published in the Journal of Neurophysiology, researchers found that much of muscle strength is based on brain activity, rather than on the mass of the muscles themselves. "There's a fair amount of evidence that you'll activate the same parts of the brain doing imagery as you do if you're actually doing the task itself," explained Brian Clark, a physiology professor at Ohio University and the study's lead author. "The basic thought is that the imagery is allowing the brain to maintain those connections."
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How energy is hidden in colours—can we use it to power a renewable future?
Credit: Pixabay
'Roses are red and violets are blue' – so says the old poem.
But why are roses red? And why are violets blue? What is it that gives something its colour?
And how could playing with colour give us wearable? This last question is at the core of research being undertaken by Dr Wallace Wong, of the University of Melbourne's Bio21 Institute and School of Chemistry.
As well as working on fascinating science that combines chemistry, physics, engineering and even some agriculture, the carbon-solar researchers of Dr Wong's lab are inspired by a renewable energy future.
But first, to grasp where they are going, you must understand a little more about the science of colour.
You could think of an object's colour as the it rejects. When objects appear to have a particular colour it's because they are absorbing all the other colours of the visible spectrum, while one colour is being reflected.
For example, the petals of a rose appear red because they absorb most of the blue light of the visible spectrum, and much of the green and yellow too. What's left to reflect back at us is dominated by the remaining reddish part of the spectrum.
It's the light that is absorbed, or reflected, that makes roses so red. Credit: Pixabay
Our perception of colour is, then, the rather clever result of our eyes and brains interpreting various combinations of those reflected colours.
Exactly which colours an object absorbs depends on all the complex molecules that make up its surface – in particular on the electrons and atomic bonds within those molecules.
To understand that, you need to know what colour really is. Light is a wave and 'colour' is merely the frequency of that wave.
The 'natural frequencies' of the myriad organic molecules that make up a rose petal correspond with frequencies of light that are – mostly – blue through yellow.
Thus, roses are red.
The Sun emits light of every possible frequency at once, including at frequencies too high or too low for us to see. But the Sun's highest intensity radiation aligns approximately with our visible range – red through blue. That's no coincidence – like all animals on Earth, we have evolved to make best use of the light available.
These days, we can also design materials to 'target' particular frequencies of light. For example, the silicon-based materials of a are tweaked to absorb the most intense frequencies in sunlight. The electrons knocked loose by that light are harvested as an electric current.
While silicon-based materials have dominated solar-cell technology since the 1970s, Dr Wong is working on alternative carbon-based materials that have the potential to allow cheaper, flexible, robust, printable solar panels.
The biggest challenge, Dr Wong explains, is efficiency. Currently, carbon-based solar cells struggle to exceed 12 per cent efficiency, significantly lagging behind the 17 per cent of commercially available silicon cells.
.One technique his laboratory is using to increase efficiency is to harvest power from a wider range of frequencies.
Dr Wallace Wong is working towards cheaper and more robust printable solar cells. Credit: University of Melbourne
By adjusting the chemical properties of the light-absorbing material, the researchers can adjust the amount of energy required to boost electrons from one state to another. When they do that, they force the material to absorb another frequency of light, ie another.
"The more frequencies these materials absorb, the more electricity they can produce," explains Dr Wong.
The ultimate aim is to absorb colours right across the high-intensity, visible part of sunlight's spectrum and a little way beyond, into ultraviolet.
So why bother? What are the advantages of carbon-based solar cells over silicon?
"One of the reasons is cost," says Dr Wong. "Because carbon-based solar cells use only microscopically-thin layers of light-absorbing materials, they should be much cheaper to produce than silicon-based cells."
One advantages of rooftop solar is decentralisation of electricity generation. Transmission infrastructure – mostly poles and wires – must be built to manage peaks, and transmitting electricity is costly.
Rooftop solar panels could be transformed by new technology. Credit: Pixabay
And it's wasteful too – about 10 per cent of Australia's electricity is lost in transmission. The more power that can be generated close to where it's used, the more those costs can be reduced.
Dr Wong says the carbon-based technology promises vastly more options for decentralised solar power generation.
"Because the carbon-based materials can be dissolved in a solvent, they can then be printed onto almost any material of any shape – using even the simplest inkjet printer. The panels are even flexible enough to be printed onto clothing – in the future we could be walking around wearing solar panels printed on our hats, coats and backpacks."
Carbon-based could also be built into or painted onto structures, so that our buildings could incorporate structures that generate power, supplementing or replacing the heavy, rigid, silicon-based solar panels on the roof.
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