text:
@ bilgi@yyd.org.tr
f +90 212 584 2385
m +90 549 384 6249
YERYÜZÜ DOKTORLARI AT A GLANCEHISTORYMISSION, VISION, PRINCIPLESBOARD OF DIRECTORSRESOURCE USAGEBANK ACCOUNT INFOJOIN US
CAMPAIGNSCRISIS AND EMERGENCY SITUATIONSPROJECTS / PROGRAMS
SITUATION REPORTSANNUAL REPORTS
Maternal And Child Health Projects
Nearly 830 women lose their lives everyday due to complications from pregnancy and childbirth. These complications mainly include infection, severe postpartum hemorrhage and high blood pressure during pregnancy.
Every year, around 20 million newborns have a low birth weight due to starvation or malnutrition before and during pregnancy, which reduces their chances of survival. These babies have a risk of death twenty times more than the other babies.
All around the world, 2 million 600 thousand babies lose their lives in their first month. According to this figure, around 7 thousand newborns die every day. Newborn deaths make up 46% of the children deaths under 5 years, and this rate was 41% in 2000. On the other hand, 99% of maternal mortalities are observed in developing countries, yet most of these deaths could be prevented if the necessary interventions and practices were provided with existing technologies and facilities in developed countries.
Yeryüzü Doktorları establishes maternal and child health clinics or improving the existing clinics in areas where delivery possibilities are limited and complications frequently occur. We provide many services such as routine check-ups for pregnant woman, delivering health births, medical control for nursing mothers, vaccination for babies, decreasing the mortality of children below 5 years and so on. Also, expectant, nursing mothers and postpartum mothers are trained on baby care and reproductive health.
Syria Azez Soran Healthcare Clinic
In Syria, we have established a clinic where maternity and primary healthcare services are provided in the district of Soran in Azez where there are nearly 130 thousand of people living. We provide birth, pregnancy follow-up and primary healthcare services are provided in our clinic which has started its operations in June 2018.
Somalia Mogadishu Maternal and Child Health Centre
We have a clinic operating in the vicinity of a refugee camp, where 50,000 internally displaced people live. It is located 13 km away from the city of Mogadishu in Somalia. Our clinic serving mother and children began their activities in May 2018, and still continues its operations today.
Somalia Ibn-i Sina Health Vocational School
In 2013, we established Ibn-i Sina Health Vocational School with the cooperation of Somali Benadir University. It first started its educational activities with 71 medical students, and continued with a total of 185 students from nursing, midwifery, laboratory technician, public health, and pharmacy departments in 2015-2016. Being 31 of them in 2014, 22 in 2015 and 26 in 2016, a total of 79 students graduated from midwifery and nursing departments at the end.
Birth Clinics in Democratic Republic of the Congo
In 2014 – 2015, we supported 2, 045 births and 16,150 examinations in rural areas by strengthening the clinics named Hewa Bora, Gambela, Mose, Kamina, Lumata, Lualaba, Ngoy-mani and Malemba. In addition, we improved the physical and technical infrastructure in Hewa Bora Hospital and Lumata and Lualaba clinics, and also contributed to the solar water well drilling in both clinics to provide a renewable energy source for the clinic.
Somalia Shifa Hospital
In 2012-2015, we facilitated a total of 1,344 births in Somalia Shifa Hospital.
Niger Koria Haoussa Maternal, Child and Nutrition Health Centre
In Niger, where access to health services is insufficient, we improved in an existing clinic in 2012 and started to support the services provided. Within the scope of these services, which continued for 15 months in the country center, we conducted the prenatal controls of a total of 935 mothers and delivered 184 births.
You can also afford a birth operation or support a pregnancy follow-up.
Cost of One Pregnancy Follow-up 170 ₺
Cost of One Childbirth 700 ₺
Aid Agency
As per article 7 of the Law on Collection of Aid numbered 2860, Yeryüzü Doktorları Association has the permission of collecting charity by the consent numbered 48918 of the İstanbul Governorship Provincial Directorate for Relations with Civil Society. The Tax Office is Davutpaşa and the Tax Number is 9500783992. In compliance with the article 16 of the Law on Collection of Aid numbered 2860, all activities are monitored by the related units of İstanbul Governorship Provincial Directorate for Relations with Civil Society.
Yeryüzü Doktorları Derneği
Kazlıçeşme Mh. Cinoğlu Çıkmazı No:3 34020
Zeytinburnu-İstanbul-Türkiye
t+90 212 586 1212
m+90 549 384 6249
@bilgi@yyd.org.tr
f+90 212 584 2385
Your online donations are safe and secure:


text:
Q: Send a tweet in symfony2's HWIOAuthBundle
I want when a user registers using twitter, to tweet automatically on his account a message.
Can I do it through HWIOAuthBundle.
I can't find anything on Google , is this even possible ?
 Thanks

A: I searched for same thing, there is nothing much, using Guzzle as service seemed to me as best solution. I'm not sure if you have to have bundle beside Guzzle lib to use it, best search pops this bundle https://github.com/ddeboer/GuzzleBundle abandoned 2 years ago. I guess whole Symfony framework is not that alive as it used to be. I considered switching to Laravel for calling Twitter Api, this lib pops up https://github.com/thujohn/twitter-l4 but those static ::methods look not much useful to me, it should be done as service. I wanted to  use framework module to call Api, but simple including twitteroauth lib makes more sense.
If you manage do call Guzzle as service in Symfony please share how you did it.

redpajama_set_name: RedPajamaStackExchange


text:
Prokaryotes and Eukaryotes
Subject Biology
Category Science
Topic Cell, Microorganisms
The theme for comparison and contrast is cell division in prokaryotes and eukaryotes. The subject has been chosen since living microorganisms are diverse and complex, and it is critical to brainstorm on the basic functional unit of life to carry out the similarities and differences between complex organisms like mammals and simple organisms like bacteria. The paper focuses on explaining the thought of prokaryote and eukaryotes, their shared similarities, and the different mechanisms of cell divisions adopted by the two classes of living organisms.
Prokaryotes and Eukaryotes are living organisms that inhabit the earth. The two types of organisms have numerous similarities and notable differences. Prokaryotes refer to unicellular organisms that do not have a cell nucleus or membrane-bound organelles. Some prokaryotes are multi-cellular. Eukaryotes are multi-cellular organisms that have cells which are divided into complex structures by the cytoskeleton and internal membranes. The nucleus is the main definitive structure of prokaryotes since it gives them their name. Both Prokaryotes and Eukaryotes undergo cell division to produce daughter cells. The process of cell division differs. Prokaryotes undergo a simple cell division while eukaryotes undergo a complex cell division process. Prokaryotes do not undergo mitosis or meiosis. They divide through the process called binary fission. Unlike prokaryotic cells, the cell division of eukaryotes is more complex. The cells of eukaryotes divide through the process of mitosis to produce different cells, and sexually through meiosis to produce identical daughter cells (O'Donnell, Langston & Stillman, 2013). The replication process of eukaryotes is more complex as compared to prokaryotes since they are complicated organisms. Binary fission occurs in prokaryotes and mitosis occurs in eukaryotes.
Cellular reproduction is based on the process of managing the replication of genetic material. A control mechanism is vital in ensuring that the DNA and cellular components are equally distributed to new cells. Binary fission is based on a simple bipolar filament in which there is the segregation of the newly formed DNA to the opposite sides of a prokaryotic cell. Mitosis entails a complex spindle structure in separating the nuclei structures of the daughter cell (Löwe & Amos, 2009).
Mitosis comprises of five separate stages that include prophase, metaphase, anaphase, telophase and cytokinesis. The prophase phase is characterized by the following: chromatic condensation; dissolution of the nuclear envelope; the migration and division of centrioles; and the formation of kinetochore fibers and spindle. During metaphase, the migration of the chromosome to the equator of the spindle occurs. The spindle becomes attached to the kinetochore fiber during metaphase. The following occurs during anaphase: separation of the centromeres; the pulling of the chromosomes to the opposing poles of the spindle. The chromosomes reach their poles in telophase. The following processes also occur during telophase: the reformation of the nuclear envelope; the uncoiling of the chromosomes to form chromatin; and the reformation of the nucleolus. Cytokinesis is the last phase of mitosis in which the splitting of the new cells occurs. The cytoplasm is split during the process, and the allocation of organelles such as the Golgi bodies takes place into each new cell Mileykovskaya & Dowhan, 2009).).
Binary fission is simple processes that occur in prokaryotic cells. The chromosome of prokaryotes is a single DNA molecule. Binary fission is characterized by the replication of the DNA molecule, and subsequent attachment of each copy of the DNA to the cell membrane. The separation of the original and replicated chromosomes occurs when the cells pull apart. The cell eventually splits apart through the process of cytokinesis. Mitosis is a complex procedure that occurs in eukaryotes, and it involves five stages.
Löwe, J., & Amos, L. A. (2009). Evolution of cytomotive filaments: the cytoskeleton from
prokaryotes to eukaryotes. The international journal of biochemistry & cell
biology, 41(2), 323-329..
Mileykovskaya, E., & Dowhan, W. (2009). Cardiolipin membrane domains in prokaryotes and
eukaryotes. Biochimica et Biophysica Acta (BBA)-Biomembranes, 1788(10), 2084-2091
O'Donnell, M., Langston, L., & Stillman, B. (2013). Principles and concepts of DNA replication
in bacteria, archaea, and eukarya. Cold Spring Harbor perspectives in biology, 5(7),
a010108.
The investigation of microorganisms
Molecular Genetics Analysis
The state of one's health
Biomimicry Explanation
Finding Evidence
Microorganisms in extreme habitats
Brain Evolution Photosynthesis

redpajama_set_name: RedPajamaCommonCrawl


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O Núcleo de Estudos de População "Elza Berquó" (NEPO) é uma unidade de pesquisa interdisciplinar e multidisciplinar na área de Demografia e Estudos de População da Universidade Estadual de Campinas (UNICAMP), localizado em Campinas, São Paulo.

Na Unicamp, os núcleos e centros não são unidades docentes, porém o Nepo participa ativamente do Programa de Pós-Graduação em Demografia do Instituto de Filosofia e Ciências Humanas da Unicamp.

Histórico

O NEPO foi criado 25 de maio de 1982, vinculado à Coordenadoria de Centros e Núcleos (Cocen) da UNICAMP, participando da consolidação da área de estudos populacionais no Doutorado em Ciências Sociais, do Instituto de Filosofia e Ciências Humanas da Unicamp. A partir de 1993, foi criado o Programa de Pós-Graduação em Demografia, nível doutorado, e em 2002, o programa incluiu o nível mestrado.

A trajetória do Nepo difere da do Cedeplar, pois não recebeu aportes específicos estrangeiros para a implementação e realização do seu programa básico, sendo mais importantes os auxílios financeiros recebidos da Finep e do CNPq. Entretanto, na realização dos seus trabalhos de pesquisa e de cursos especializados, o Nepo recebeu apoios significativos da Fundação Ford, do Fundo de População das Nações Unidas (UNFPA) e de outros como o apoio da Fundação Ford para o Programa de Saúde Reprodutiva e Sexualidade (1990-2004) e para o Programa Interinstitucional de Treinamento em Metodologia de Pesquisa em Gênero, Sexualidade e Saúde Reprodutiva (1994-2004), assim como o apoio do UNFPA para o Programa Interinstitucional de Avaliação e Acompanhamento das Migrações Internacionais no Brasil.

Em 1996, o Núcleo de Estudos de População obteve o "título" de núcleo de excelência em pesquisa, ao ter aprovado o projeto Redistribuição da População e Meio Ambiente: São Paulo e Centro-Oeste sob a coordenação de Daniel Joseph Hogan, que também foi coordenador do núcleo de 1998 até 2001.

Linhas de Pesquisa

O NEPO atua em diferentes linhas de pesquisa: Demografia das Etnias; Demografia e Políticas Públicas; Demografia Histórica; Família, Gênero e População; Redistribuição Espacial da População; População e Ambiente; População e Saúde; Saúde Reprodutiva e Sexualidade.

Ver também
 Fundo de População das Nações Unidas (UNFPA)
 Centro de Desenvolvimento e Planejamento Regional (Cedeplar) da UFMG
 Instituto de Filosofia e Ciências Humanas da Unicamp (IFCH/Unicamp)

Ligações externas

 Página oficial do NEPO
 Página oficial da Pós Graduação em Demografia da Unicamp

Universidade Estadual de Campinas
Fundações em São Paulo em 1982

redpajama_set_name: RedPajamaWikipedia


The Grand Prix Farms real estate is conveniently located in Wellington, next to the horse show grounds. Here you will find some of the most luxurious and well equipped equestrian farms in Florida.
View listings for Grand Prix homes, or learn more about amenities in this upscale equestrian community.
Grand Prix residents have use of the 2 barns with a total of 64 stalls, 8 tack rooms, 2 manure bins, huge sand rings, 4 large paddocks and plenty of parking spaces. Grand Prix homes receive community water.
To learn more about Grand Prix homes, please email or call (561) 746-7272 and one of our team will be happy to answer your queries.


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Home / PLDT Home / PLDT Home Ultera / Tech News / PLDT Accelerates Home Ultera's Network Migration
PLDT Accelerates Home Ultera's Network Migration
July 28, 2022 PLDT Home, PLDT Home Ultera, Tech News
PLDT Inc. announces the completion of its initiatives to transition its Home Ultera traditional fixed wireless service into improved and faster fixed wired and wireless service.
PLDT will decommission around 185 cellular towers that provide Time-Division Duplex Long-Term Evolution or TD-LTE connectivity to Home Ultera by the end of July 2022.
This means that over 3,000 Home Ultera customers who are eligible for service migration will have the choice of migrating to higher-speed fixed fiber plans or to a postpaid wireless service for the home at no additional cost and for an improved customer experience.
Customers migrating to Home Fiber will also receive complimentary installation and modem fees.
This migration initiative will cover 58 areas in the Philippines including Abra, Agusan del Sur, Aklan, Albay, Antique, Basilan, Bataan, Batangas, Benguet, Biliran, Bohol, Bukidnon, Bulacan, Cagayan, Camarines Norte, Camarines Sur, Capiz, Cavite, Cebu, Davao de Oro, Davao del Norte, Davao del Sur, Davao Oriental, Eastern Samar, Guimaras, Ifugao, Ilocos Norte, Ilocos Sur, Iloilo, La Union, Laguna, Lanao del Norte, Maguindanao, Metro Manila, Misamis Occidental, Misamis
The decommissioning follows PLDT's announcement of the sale of the tower earlier this year. In April, PLDT announced a first-of-its-kind sale-and-leaseback agreement for 5,907 telecom towers as part of its strategic transformation to increase network investment and efficiency.
PLDT remains the only telco provider in the Philippines that can deliver up to 10,000 Mbps fiber-optic service. It's PLDT Home unit provides the fastest internet to over 3.1 million fiber subscribers through its nation-widest infrastructure reaching over 803,000 kilometers, 15.5 million homes passed, and a total fiber capacity of 6.25 million ports. This fiber network also connects the nationwide wireless LTE and 5G network of PLDT and Smart, connecting each cell site to each other and to the core, and providing LTE and 5G coverage to customers from Batanes to Tawi-Tawi.
PLDT Accelerates Home Ultera's Network Migration Reviewed by Bam - Adobotech on July 28, 2022 Rating: 5


With the arrival of the New Year, the stock markets around the world have started immediately to act frantically to defend from the high volatility and Chinese macroeconomic data. Also, the price of oil continues to fall as in 2015; this time due to concerns on the conflict between Iran and Saudi Arabia.
Surely someone was waiting for it already, but the first 'cause of crisis' of 2016 in the markets was caused by China. China has grown so much faster and its positive expansion has affected all Western countries, especially those who had/have an economic crisis (China bought a part or their entire debt) and the countries of South America from which China buy raw materials.
The main problem is that the Chinese market is evolving just as quickly and the demand for raw materials is falling. In fact, as it has been evidenced by the data on Monday, the manufacturing sector has suffered a new contraction in December after two months of stability.
In response to this, the two Chinese stock markets (Shanghai and Shenzhen) closed with a loss of 7%, triggering for the first time of the year the 'circuit bakers' (the mechanism for the suspension of shares trading). Subsequently, during Tuesday's session, the Popular Bank of China announced an injection of liquidity into the money markets in the amount of $ 20 billion.
The collapse of the Chinese stock exchanges has also plagued the international ones: the Japanese stock market closed losing 3%; the Dow Jones fell below the 17,000 level for the first time since October 2015 and the NASDAQ has lost more than 3%; among all the European market stocks, Frankfurt Dax at -0.52%.
It also continues the devaluation of the Chinese Yuan leaking in more than 5% in two months against the dollar.
The prices of the black gold were significantly affected by the conflicts in the Middle East and by the strong concerns about the worldwide excess of supply.
Usually, when concerns over production in the Persian Gulf are strong, the price of oil tends to rise, but at the beginning of 2016, oil prices continue to fluctuate wildly.
Actually, oil prices rose at first, and then decreased both in the European and in the American sessions. Brent reached $ 36.85 per barrel, while in London, it fluctuated around 37 $ this morning.
January, the 5th were also published data on Europe inflation: consumer prices posted from Eurostat showed that inflation grew less than expected, still far from ECB target.
The 2016 did not start certainly on the sly, so let's see what awaits us in the first month of the year. The more important will be on January, the 8th when USA will show the data about Non-Farm Payrolls. This is a very important indicator about the health of the US economy.
About US we will have also: US inflation (the 20th); Federal Reserve meeting (the 27th); GDP (the 29th).
We will look carefully also to the macroeconomic data in China: inflation and producer prices (January, the 10th) and GDP fourth quarter of 2015 (the 19th).
About Eurozone, we will wait for: Bank of England meeting (the 14th); EBC meeting and press conference (the 21st); UK GDP and German inflation (both on the 28th); January Eurozone inflation (the 29th).
New Year has started off with a bang, don't you think?


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The Isle of Man
Home from home charm on a unique island
6 days From £599 per person
2022 Tour code: 22MXS
From your base in seaside Douglas, visit the Isle of Man's traditional towns, pretty fishing ports and breathtakingly picturesque coastline as you travel on historic railways and soak up the unique culture of the island.
Step back in time as you travel in the vintage carriages of the Isle of Man Steam Railway, through lush countryside and along the scenic southern coast to Port Erin.
Journey on the Manx Electric Railway through beautiful countryside, across gorse-topped hills, aboard the oldest working tramcars in the world.
Embark on a scenic journey to the summit of Snaefell, the island's only mountain, on the Snaefell Mountain Railway, travelling in delightful wooden-bodied rail cars dating back to 1895.
Standard Class Rail
Heritage Rail Excursions
3* Hotel accommodation
The services of a professional UK Tour Manager from start to finish
Explorer Pass for free local transport and Heritage Pass for entrance to Manx National Heritage Sites
5 Breakfasts and 5 Dinners
Day 1 - Heysham and Douglas
Arrive in Heysham, Lancashire, ahead of your early afternoon ferry journey to the Isle of Man. You arrive in the coastal resort town of Douglas, the island's capital, and transfer to your hotel close to the seafront. An island reminiscent of a bygone age, the Isle of Man is bursting with unique culture and heritage, and charming Douglas is the perfect spot from which to experience the best of it.
Day 2 - Isle of Man Steam Railway
Enjoy a horse-drawn tram ride along the promenade before a nostalgic journey on the Isle of Man Steam Railway, the island's oldest rail system. Sit back in the restored carriages as you take in countryside views on your way to Port Erin. A scenic drive takes you to the headland, overlooking the Calf of Man, where you can keep watch for seals and nesting birds. Later, travel to Castletown, the island's former capital. Castle Rushen dominates the town and the Nautical Museum and Old House of Keys are all worth a visit. Entrance to all three sites is included with your Heritage Explorer Pass. Return to Douglas, travelling over the Fairy Bridge where locals traditionally greet the fairies as they cross.
Breakfast, Dinner
Day 3 - Peel
Travel to the fishing port of Peel, stopping at Tynwald Hill, the meeting place of the Manx parliamentary assembly. In Peel you have free time. Its thriving fishing industry and smokehouses have made it famous for its kippers, which you can buy from a number of local shops. You could also visit Peel Castle, located on St Patrick's Isle, or the House of Manannan, which explores the island's Celtic, Viking and Maritime heritage. Later, drive along a section of the famous TT racing circuit on the way to Ramsey, where you journey on the Manx Electric Railway back to Douglas, travelling through glorious countryside, across gorse-topped hills, and along the stunning coast.
Day 4 - The Snaefell Mountain Railway
Begin the day aboard the Manx Electric Railway, travelling to the fishing village of Laxey. Here, join the Snaefell Mountain Railway - the only electric mountain railway in the British Isles - for a scenic journey that takes you up to the peak of Snaefell. Snaefell is the highest mountain on the Isle of Man, and the views from the summit are stunning. On a clear day, it's possible to see England, Ireland, Northern Ireland, Scotland and Wales. Return to Laxey where you have free time. Make sure you pay a visit to Laxey Wheel, the world's largest working waterwheel.
Day 5 - Douglas
Today is free for you to discover the island using your included Explorer Pass for travel on local transport, and your Heritage Pass for entrance to Manx National Heritage Sites. You could visit the Victorian Gaiety Theatre on Douglas promenade, which has undergone careful restoration to ensure it retains its historical charms. Or, step back in time at the Grove Museum of Victorian Life, a beautifully preserved Victorian house with authentic period rooms, original furnishings and a costume room.
Day 6 - Heysham & home
Leave Douglas on the morning ferry, arriving back into Heysham just after midday. On arrival, you're free to make your way home.
Departure times
We depart from Heysham to the Isle of Man at approximately 2:15pm on the first day of your holiday. On the return trip, our ferry docks in Heysham at around 12:15pm.
However, we will write to you around 10 weeks before your departure date with the precise meeting times for your tour group.
Ascot Hotel, Douglas
Isle of Man Steam Railway
Manx Electric Railway
Snaefell Mountain Railway
Rail travel to and from Heysham
Extend your UK & Ireland holiday
4.6 / 5 · 134 reviews
Philip Dyson-Hurrell
Submitted 25 Oct 2021
A fantastic 0la
Collected by Trustpilot
Florence Farman
Extremely good value for money. Very comfortable, clean and friendly hotel; good wholesome food and nothing too much trouble for the staff! Will definitely return and have recommended it to several friends. Ivan, out tour guide, was very knowledgeable and helpful without being too intrusive.
R Bilson
Very interesting and well prepared With Terry in charge very Lovely lady and very helpful.
Barbara Sparling
The only thing that let this holiday down a notch was the poor weather on the Tuesday when we went up Snaefell..... but otherwise it was well managed, Ivan was a good communicator and the hotel was excellent. Dave, our coach driver was very knowledgeable, and friendly as well.
Colin Hancox
Very enjoyable week well organised
Clare and Pam Brydon
Liked the isle of man
Show 6 more reviews
European Escorted Holidays by Rail 2022
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We've collated some of the most appetising and appealing recipes to really help you make the most of Autumn and to get you inspired to cook up a storm for family, friends, or perhaps just your own indulgent moment.


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El Castillo, Chichen Itza
El Castillo (Spanish pronunciation: [el kas'tiʎo], Spanish for "the castle"), also known as the Temple of Kukulcan (or sometimes Kukulkan), is a Mesoamerican step-pyramid that dominates the center of the Chichen Itza archaeological site in the Mexican state of Yucatán. The building is more formally designated by archaeologists as Chichen Itza Structure 5B18.
El Castillo, Chichen Itzá
North-west view of El Castillo
Constructed
8th–12th century
Mesoamerican Step pyramid
24 m (79 ft), without temple
30 m (98 ft), with temple
6 m (20 ft), Temple itself
55.3 m (181 ft)
37°29'44" (edges)
47º19'50" (sides)
Tinum Municipality, Mexico
Pre-Hispanic City of Chichen-Itza
Cultural: (i), (ii), (iii)
1988 (12th Session)
20°40′58.4″N 88°34′7.0″W / 20.682889°N 88.568611°W / 20.682889; -88.568611Coordinates: 20°40′58.4″N 88°34′7.0″W / 20.682889°N 88.568611°W / 20.682889; -88.568611
Location of El Castillo, Chichen Itza in Mexico
Built by the pre-Columbian Maya civilization sometime between the 9th and 12th centuries CE or AD, El Castillo served as a temple to the god Kukulkan, the Yucatec Maya Feathered Serpent deity closely related to the god Quetzalcoatl known to the Aztecs and other central Mexican cultures of the Postclassic period.
The pyramid consists of a series of square terraces with stairways up each of the four sides to the temple on top. Sculptures of plumed serpents run down the sides of the northern balustrade. Around the spring and autumn equinoxes, the late afternoon sun strikes off the northwest corner of the pyramid and casts a series of triangular shadows against the northwest balustrade, creating the illusion of a feathered serpent "crawling" down the pyramid. The event has been very popular and is witnessed by thousands of visitors at the spring equinox, but it is questionable whether it is a result of a purposeful design, because the light-and-shadow effect can be observed, without major changes, during several weeks around the equinoxes.[1] Each of the pyramid's four sides has around 91 steps which, when added together and including the temple platform on top as the final "step",may produce a total of 365 steps (the steps on the south side of the pyramid are eroded) (which is equal to the number of days of the Haab' year).[2]
The structure is 24 m (79 ft) high, plus an additional 6 m (20 ft) for the temple. The square base measures 55.3 m (181 ft) across.
ConstructionEdit
The construction of El Castillo, like other Mesoamerican pyramids, likely reflected the common practice of executing several phases of construction. The last construction probably took place between 900-1000 CE, while the substructure may have been constructed between 600-800 AD. Based on archaeological research, construction of El Castillo was based on the concept of axis mundi.[3] It is thought that the space remained sacred regardless of the structure positioned on the location. When a temple or pyramid structure was renewed, the former construction was ritually destroyed, which involved resolving the space of spiritual forces to preserve its sacredness.[4] It is estimated that this construction dates to the eleventh century CE. After all of the work was completed, an entryway was cut into the balustrade of the northeastern exterior staircase to provide access to tourists. The older, inner pyramid is referred to as the "substructure".
Inside the pyramidEdit
In 1566, the pyramid was described by Friar Diego de Landa in the manuscript known as Yucatán at the Time of the Spanish Encounter (Relación de las cosas de Yucatán). Almost three centuries later, John Lloyd Stephens described with even more detail the architecture of the pyramid in his book Incidents of Travel in Yucatán (Incidentes del viaje Yucatán), published in 1843. At that time, the archaeological site of Chichén Itzá was located on an estate, also called Chichén Itzá, owned by Juan Sosa. Frederick Catherwood illustrated the book with lithographs depicting the pyramid covered in abundant vegetation on all sides. There are some photographs taken in the beginning of the 20th century that also show the pyramid partially covered by said vegetation.
In 1924, the Carnegie Institution for Science in Washington, D.C. requested permission from the Mexican government to carry out explorations and restoration efforts in and around the area of Chichen Itza. In 1927, with the assistance of Mexican archaeologists, they started the task. In April 1931, looking to confirm the hypothesis that the structure of the pyramid of Kukulkan was built on top of a much older pyramid, the work of excavation and exploration began in spite of generalized beliefs contrary to that hypothesis. On June 7, 1932, a box with coral, obsidian, and turquoise encrusted objects was found alongside human remains, which are exhibited in the National Anthropology Museum in Mexico City.
El Castillo is located above a cavity filled with water, labeled a sinkhole or cenote. Recent archaeological investigations suggest that an earlier construction phase is located closer to the south-east cenote, rather than being centered.[5] This specific proximity to the cenote suggests that the Maya may have been aware of the cenote's existence and purposefully constructed there to facilitate their religious beliefs.[6]
After extensive work, in April 1935, a Chac Mool statue, with its nails, teeth, and eyes inlaid with mother of pearl was found inside the pyramid. The room where the discovery was made was nicknamed the "Hall of offerings" or "North Chamber". After more than a year of excavation, in August 1936, a second room was found, only meters away from the first. Inside this room, dubbed the "Chamber of Sacrifices", archaeologists found two parallel rows of human bone set into the back wall, as well as a red jaguar statue. Both deposits of human remains were found oriented north-northeast. Researchers concluded that there must be an inner pyramid approximately 33 m (108 ft) wide, shaped similarly to the outer pyramid, with nine steps and a height of 17 m (56 ft) up to the base of the temple where the Chac Mool and the jaguar were found.
The discovery of what appears to be a throne (referred to as the "Red Jaguar") in the throne room was previously assumed to have been decorated with flint and green stone discs, but recent research has determined the jaguar to be composed of highly symbolic and valued materials for ritualistic significance. The use of x-ray fluorescence (pXRF) was used to determine that the sculpture is painted red with a pigment that includes cinnabar, or mercury sulfide (HgS)[7]. Cinnabar was not in accessible proximity to Chichén Itzá, so the transportation of this pigment through long-distance trade placed a high value of this product.[7] Additionally, the color red appears to be significant to Maya symbolism, and it is associated with creating life as well as death and sacrifice.[8] Studies suggest that objects in Maya culture were imbued with vital essence, so the choice of painting the jaguar red may be a reflection of these beliefs, deeming the jaguar as an offering.[9] The high-status associated with the cinnabar pigment and its red tone suggest that the jaguar was linked to ritual importance of closing a temple for renewal.[10]
The four fangs of the Red Jaguar have been identified as gastropod mollusk shells (Lobatus costatus) using a digital microscope and comparative analysis from malacology experts from the National Institute of Anthropology and History, another valued resource that may have been traded into Chichén Itzá.[11] The green stones were also analyzed and determined to be a form of jadeite.[12] Jadeite was valuable economically and socially, and the acquisition and application of the material is indicative of the access Chichén Itzá had along its trade routes.[13]
Archaeological studies indicate that the Red Jaguar is similar to other depictions of thrones found in murals (Temple of Chacmool), thus whomever was seated on this throne could have been accessing the point of axis mundi, which is essential to the elements and relationship to the cosmological system.[14] The symbolic usage of materials related to the underworld and death also suggest that it acted as an offering for ritually closing the temple.[15]
El Castillo before excavation, 1860
Situation map of El Castillo
North side of El Castillo
Plumed Serpent (Kukulkan)
Chichen Itza Equinox
Ballcourt
AlignmentEdit
The location of the pyramid is aligned at the intersection between four cenotes: the Sacred Cenote, Xtoloc, Kanjuyum, and Holtún. This alignment supports the position of El Castillo as an axis mundi.[16] The western and eastern sides of the temple are angled to the zenith sunset and nadir sunrise, which may correspond with other calendar events such as start of the traditional planting and harvesting seasons.[17] However, the approximate correspondence with the Sun's positions on its zenith and nadir passages is likely coincidental, because very few Mesoamerican orientations match these events and even for such cases a different explanation is much more likely.[18] Since the sunrise and sunset dates recorded by solar orientations, which prevail in Mesoamerican architecture, tend to be separated by multiples of 13 and 20 days (i.e. of basic periods of the calendrical system), and given their clustering in certain seasons of the year, it has been argued that the orientations allowed the use of observational calendars intended to facilitate a proper scheduling of agricultural and related ritual activities. In agreement with this pattern, detected both in the Maya Lowlands[19] and elsewhere in Mesoamerica,[20] the north (and main) face of El Castillo at Chichén Itzá has an azimuth of 111.72°, corresponding to sunsets on May 20 and July 24, separated by 65 and 300 days (multiples of 13 and 20). Significantly, the same dates are recorded by El Castillo at Tulum.[21]
Comparison of approximate profiles of the El Castillo, Chichen Itza with some notable pyramidal or near-pyramidal buildings. Dotted lines indicate original heights, where data are available. In its SVG file, hover over a pyramid to highlight and click for its article.
Recent developmentsEdit
In recent years, the National Institute of Anthropology and History (INAH), which manages the archaeological site of Chichen Itza, has been closing monuments to the public. While visitors can walk around them, they can no longer climb them or go inside their chambers. Climbing El Castillo was stopped in 2006, after a woman fell to her death. At the same time INAH closed public access to the interior throne room.[22]
Today "El Castillo" is one of the most recognized and widely visited pre-Columbian structures in present-day Mexico.[23]
Additionally, researchers have discovered an enormous cenote (also known as a sinkhole) beneath the 1,000-year-old temple of Kulkulkan. The forming sinkhole beneath the temple is around 82 by 114 feet (25 by 35 meters) and up to 65 feet (20 meters) deep. The water filling the cavern is thought to run from north to south.
Researchers also found a layer of limestone about 16 feet (4.9 meters) thick at the top of the cenote, on which the pyramid is sitting.
Recent archaeological investigations have utilized Electrical Resistivity Tomography (ERT) to examine the construction sequence of El Castillo.[24] To preserve the site from potential damage, electrodes were placed non-traditionally as flat-based detectors around the quadrangle of the pyramid bodies of the pyramid. After each pyramidal body was tested, the data revealed two previous construction phases within El Castillo with a possible temple at the top of the second substructure. Determining the dates of when these constructions happened will provide time periods of when Chichen Itza may have been significantly occupied.[25]
List of Mesoamerican pyramids
Pyramid of the Magician at Uxmal
Tikal Temple I
Tikal Temple II
Tikal Temple III
Tikal Temple IV
Tikal Temple V
^ Šprajc, Ivan; Sánchez Nava, Pedro Francisco (2018). "El Sol en Chichén Itzá y Dzibilchaltún: la supuesta importancia de los equinoccios en Mesoamérica". Arqueología Mexicana. XXV (149): 26–31.
^ Milbrath 1989: 66
^ Tejero-Andrade, A., Argote-Espino, D., Cifuentes-Nava, G., Hernández-Quintero, E., Chávez, R.E., & García-Serrano, A. (2018). 'Illuminating' the interior of Kukulkan's Pyramid, Chichén Itzá, Mexico, by means of a non-conventional ERT geophysical survey. Journal of Archaeological Science, 90, 1-11.
^ a b Juárez-Rodríguez, O., Argote-Espino D., Santos-Ramírez, M., & López-García, P. (2017). Portable XRF analysis for the identification of raw materials of the Red Jaguar sculpture in Chichén Itzá, Mexico. Quaternary International, Quaternary International.
^ Juárez-Rodríguez, O., Argote-Espino D., Santos-Ramírez, M., & López-García, P. (2017). Portable XRF analysis for the identification of raw materials of the Red Jaguar sculpture in Chichén Itzá, Mexico. Quaternary International, Quaternary International.
^ Wren, L., Kristan-Graham, C., Nygard, T., & Spencer, K. R. (2018). Landscapes of the Itza : Archaeology and art history at Chichen Itza and neighboring sites. Gainesville: University Press of Florida.
^ Šprajc, Ivan (2018). "Zenith and nadir passages of the Sun in Mesoamerica". Journal of Skyscape Archaeology. 4 (1): 108–117. doi:10.1558/jsa.36092.
^ Sánchez Nava, Pedro Francisco; Šprajc, Ivan (2015). Orientaciones astronómicas en la arquitectura maya de las tierras bajas. Mexico City: Instituto Nacional de Antropología e Historia. ISBN 978-607-484-727-7.
^ Šprajc, Ivan (2018). "Astronomy, Architecture, and Landscape in Prehispanic Mesoamerica". Journal of Archaeological Research. 26 (2): 197–251. doi:10.1007/s10814-017-9109-z.
^ Šprajc, Ivan; Sánchez Nava, Pedro Francisco (2013). "Astronomía en la arquitectura de Chichén Itzá: una reevaluación". Estudios de Cultura Maya. XLI: 31–60. doi:10.19130/iifl.ecm.2013.41.153.
^ Diario de Yucatan, "Fin a una exención para los mexicanos: Pagarán el día del equinoccio en la zona arqueológica," March 3, 2006.
^ Coe 1999: 176
Coe, Michael D. (1999). The Maya. Ancient peoples and places series (6th, fully revised and expanded ed.). London and New York: Thames & Hudson. ISBN 0-500-28066-5. OCLC 59432778.
Milbrath, Susan (1999). Star Gods of the Maya: Astronomy in Art, Folklore, and Calendars. The Linda Schele series in Maya and pre-Columbian studies. Austin: University of Texas Press. ISBN 0-292-75225-3. OCLC 40848420.
Šprajc, Ivan, and Pedro Francisco Sánchez Nava (2013). Astronomía en la arquitectura de Chichén Itzá: una reevaluación. Estudios de Cultura Maya XLI: p. 31–60.
Willard, T.A. (1941). Kukulcan, the Bearded Conqueror : New Mayan Discoveries. Hollywood, CA: Murray and Gee. OCLC 3491500.
Gray, Richard. "Sacred Sinkhole Discovered 1,000-year-old-Mayan-Temple-Eventually-Destroy-Pyramid." Science & tech August 17, 2015. Dailymail. Web. August 17, 2015.
Justice, Adam. "Scientists discover sacred sinkhole cave under Chichen Itza pyramid." Science (2015). Ibtimes. Web. August 14, 2015.
Juárez-Rodríguez, O., Argote-Espino D., Santos-Ramírez, M., & López-García, P. (2017). Portable XRF analysis for the identification of raw materials of the Red Jaguar sculpture in Chichén Itzá, Mexico. Quaternary International, Quaternary International.
Tejero-Andrade, A., Argote-Espino, D., Cifuentes-Nava, G., Hernández-Quintero, E., Chávez, R.E., & García-Serrano, A. (2018). 'Illuminating' the interior of Kukulkan's Pyramid, Chichén Itzá, Mexico, by means of a non-conventional ERT geophysical survey. Journal of Archaeological Science, 90, 1-11.
Wren, L., Kristan-Graham, C., Nygard, T., & Spencer, K. R. (2018). Landscapes of the Itza : Archaeology and art history at Chichen Itza and neighboring sites. Gainesville: University Press of Florida.
Retrieved from "https://en.wikipedia.org/w/index.php?title=El_Castillo,_Chichen_Itza&oldid=896285790"


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text:
More Bad News For Forest Gate Developers
Aston-Mansfield, one of Newham's oldest charities and the owner of Durning Hall Community Centre, has today issued a statement on its formal objection to controversial regeneration proposals for Forest Gate submitted by developers Obsidian.
Last month, Obsidian's plans were rejected by Mayor of London Boris Johnson, with the Greater London Authority questioning the suitability of a 20 storey tower block on the current Durning Hall site and raising serious concerns about the lack of clarity on a range of issues from affordable housing to community facilities. Now the objection of a significant Forest Gate landowner - as well as Durning Hall, the charity owns a number of other properties in Woodgrange Road and Earlham Grove - has put further pressure on Obsidian to drastically change its plans. Whilst accepting that Forest Gate is in urgent need of redevelopment (lets not talk about the £92 million spent on the seven-year SRB programme that was supposed to rejuvenate the area), the charity's statement says:
Aston-Mansfield supports the principle of regenerating Forest Gate but does not believe that the proposals set out in the current Obsidian planning applications adequately meet the Council's regeneration objectives nor are they in the best interests of the local residents and community groups. In particular:
The volume of space that Aston Mansfield currently provides for community use in Forest Gate is more than two and a half times larger than the amount proposed in the application;
We agree with high density housing near the station but think the proposed tower requires much greater justification both in terms of visual impact and financial viability;
The application makes no contribution to affordable housing and no mention of how the temporary hostel for homeless people provided within Durning Hall will be replaced or improved;
The five phase development proposed could disrupt life and work in the area for years causing operational difficulties and planning blight that will severely compromise our work;
There is no indication as to how the Charity is expected to maintain its services whilst the Durning Hall site is redeveloped.
Consequently the Charity is unable to support the application as it currently stands and is working on some constructive suggestions to put to Obsidian and the Council if the current application can be deferred for further consultation.
If this does not happen there is a real danger that Durning Hall will have to close during the period of redevelopment and may not be able to reopen in Forest Gate.
Aston-Mansfield's intervention will make it far more difficult for Newham council, which has been supportive of Obsidian's proposals, to make an early decision on the planning application in its current form. The planning committee is due to meet on on 21 February and if it decides to reject the call for further consultation and grant planning approval, the developers have said they aim to start construction work this year.
The Save Forest Gate camnpaign continues to call for local people to lobby councillors - more information here.


Hello and welcome to Eternal Runner! I'm Jeremy the creator of the website!
While most people look at me with disgust when I say this … I have always enjoyed running.
I started out in middle school and high school by running track and cross-country. While I enjoyed the competition back then, as I got older I decided I only wanted to keep running for myself and for my own enjoyment. Not that there is anything wrong with trying to stay competitive in races. I commend those who run to compete in marathons, 5k's, etc. I admit that I enjoy an occasional 5k now and then, but I don't ever worry about how I am doing compared to others. It's fun to join a bigger group of other individuals who enjoy running just as much as you at those types of events.
I will say there were two moments that were not enjoyable during my running times. There were two separate occasions when I sprained each ankle. Luckily, I am a nurse and knew how to care for the ankles when I sprained them, but it did sideline me for a while with each time. This probably is the only time that should bother you when you're trying to build up and continue your running regimen as it is quite frustrating. However, make sure you take care of yourself when you are injured as you do not want to injure yourself even more.
Despite these two instances that set me back for a period of time, running is still a part of my life. I love when the weather warms up outside and I can lace up my shoes, put on my headphones, and breathe the fresh air while I swing those arms and put one foot in front of the other.
I want to share my knowledge and what I learn about running with you.
By staying up-to-date on topics related to running, the beginning runner may be able to keep up their motivation, or the experienced runner might find a new training technique. In addition, since I am a registered nurse, you may see health topics related to running.
The runners' community is a strong and powerful one and I want to contribute to that community by reaching an audience who is passionate about running.
What Does Eternal Runner Offer You?
Eternal Runner is here to offer up-to-date advice, trends, and news about running. We'll cover topics anywhere from A to Z related to running. You might see an article about a new training tip, the many benefits of running, recommended techniques about running form, or how to manage a sprained ankle (trust me I have experience on sprained ankles like I shared with you above).
Hopefully you'll learn something new that will help you achieve your running goals, your motivations will stay high, and you'll just keep up with the vast world of running.
If you ever need a hand or have any questions, feel free to email me at jeremy@eternalrunner.com and I will be more than happy to help you out.


Dear Sasha, here is your special web birthday gift. It is a very small book of some photos of you in a PDF file. As you cannot put PDF files on your old fashioned blog, the food bearer asked us to put it on our blog for you.
p.s. It took a long time for us to make your birthday card and we hope you are grateful.
on the web for you.
Princess Aurora, that was a lovely present you and the other fishes did !
We liked the pictures and we are sure Sasha will too.
We also wish Sasha a happy day for his birthday.
Thank you for coming to see us. We would like to be your friends.


Association of Washington Business, Coalition on College Cost Savings, College Success Foundation, Council of Independent Colleges, Education Research and Data Center, Joint Transfer Council, National Association of Independent Colleges and Universities, NAICU State Executives, Seattle and Washington College Access Networks,State Board for Community and Technical Colleges, Washington Association of Colleges of Teacher Education, Washington Council of High School-College Relations, Washington Scholarship Coalition, Washington Financial Aid Association, Washington Higher Education Facilities Authority, Washington State Institute for Public Policy, Washington Student Achievement Council and many others.
We have lots of love to give, and our campuses do too.
experienced professors and focused classmates.
A freshman at Seattle Pacific University (SPU), Sandy is living her dream. For Sandy, enrolling at SPU took much more than simply filling out the application. As one of the first in her extended family to attend college, Sandy is changing the way her family has been and will be for generations.
Since she was in 8th grade, Sandy, her mom and her step-father have been living in a low-budget motel in the SeaTac area. Looking back to her great-grandmother's generation, Sandy says that most of her family members had children at a very young age, creating an economic burden and limiting access to higher education. Many received state assistance to support themselves and their children, creating a cycle of poverty.
As one of the first students to enroll in ICW's new Matched College Savings Program (MCSP), Sandy's commitment to breaking that cycle and getting "a good start in life" with a quality education has a special significance in both her family's and Washington's history.
What is MCSP? The Matched Colleges Savings Program is Washington's first asset building program for students enrolled in Washington's independent colleges. The program works by matching student savings 5:1 with a combination of federal and private funds. Students are required to save a minimum of $44 every month for 36-months and to attend a 10-hour financial literacy class. By the end of the program, enrolled students will have access to a minimum of $9,584 to apply toward tuition and/or college-related supplies. Unlike a scholarship, the MCSP is based entirely on income eligibility – students must be at or below 200% of poverty level – and the student's commitment to save toward college expenses and earning their degree.
Sandy plans to continue to do her best by earning her degree in Accounting, Business Administration or International Business with a minor in German so that she can live and work in Germany someday. She also intends to set a new example for her family, especially her 2-year-old niece.
Just what is a "liberal arts" degree? While content varies with majors, there are a number of fundamental skills cultivated across the diverse array of liberal arts degrees.
Liberal arts majors learn how to learn. Technology is changing ever more rapidly. The challenges that will face industries and our society 20 years from now cannot yet be imagined. The versatility, adaptability and flexibility of liberal arts graduates speak to some of their most important and enduring assets.
An education in the liberal arts equips graduates to apply all these skills within an ethical framework.
We hear a lot these days from policymakers, business leaders and editorial writers about science, technology, engineering and mathematics (STEM) disciplines. There are sound reasons for placing a high priority on these subjects.
The colleges that are members of Independent Colleges of Washington are doing their share – and more – in these high priority fields.
While our colleges produce one in five bachelor's and higher level degrees conferred in Washington across all fields of study, we produce 23 percent of the bachelors degrees in biology and health professions, 25% of the math and statistics degrees, 30% of the physical science degrees and and 33 percent of the nursing degrees.
While ICW-member colleges are in full support of expanding STEM degree production, our colleges never forget their foundation, their roots and their missions.
Our colleges are proud to be grounded in the liberal arts. Washington's higher education system must help to raise overall educational attainment, provide opportunities for social mobility and strengthen the foundation for a more innovative and dynamic state economy. The liberal arts are crucial not only for boosting STEM degree production but also for achieving these broader goals.
STEM graduates need coursework in a wide range of fields, from literature and philosophy to music and history, to achieve a well-balanced broad education.
Students earning degrees in fields outside the STEM disciplines are every bit as important to our state's economic and social future as our STEM majors are.
A college education is preparation for a lifetime of work, not just the first entry-level job out of college.
Even in times like these when liberal arts graduates may have a little tougher time getting careers started, "evidence shows that they tend to advance farther and be more sought out by CEOs for high-level jobs," according to Katharine Hansen, who writes for the job-hunting website Quintessential Careers. Liberal arts graduates rarely find themselves restricted to just one career path, as is sometimes the case in more specific, technical fields.
According to the Collegiate Employment Research Institute, recent surveys of employers show that 40 percent of employers do not care which major an undergraduate chose because they are simply looking for good people from all majors. Many other employers look for a balance that includes both technical training and a liberal arts education.
No college degree is a guarantee of a great job offer the day after graduation. But liberal arts graduates are well positioned to succeed over the long haul in one or many career directions – in addition to having the tools for being engaged citizens, ethical members of the community, and active contributors to the well-being of themselves, their families and our society.
In 2007, the College Bound Scholarship program was launched to improve high school graduation and college enrollment rates for low-income students by offering an early promise of financial aid to qualifying 7th and 8th graders. Students who kept good grades and out of trouble through high school would receive a scholarship to cover tuition (at public college rates) plus a small book allowance. The College Bound Scholarship award follows the student and may be used at two- or four-year public and private colleges and universities in Washington, including all ten ICW member colleges, and combines with State Need Grant and other state financial aid.
The 2013 College Bound All-Stars (below) join the larger "team" of Student Aid All-Stars whose individual stories represent the four thousand other State Need Grant eligible or receiving students at our ten member, private non-profit colleges. Six years ago, College Bound Scholars committed to good citizenship and rigorous scholarship. They maintained that commitment through high school and are now are on the path to success.


text:
\section{Introduction}

Lithium abundances in stellar atmospheres are key observables in astrophysics, giving crucial information on stellar evolution and mixing, stellar and Big Bang nucleosynthesis, cosmic ray spallation, and perhaps even planet formation \citep[e.g.][]{1993PhST...47..186L, 1994A&A...288..860C, 2010Ap&SS.328..193M}.  Such abundances are interpreted from observations of the few Li I lines found in stellar spectra, and to obtain accurate results, it is important to account for departures from local thermodynamic equilibrium (LTE) \citep{1984A&A...130..319S,1994A&A...288..860C, Lind2009}.  Reliable modelling of line formation in non-LTE requires detailed knowledge of all important radiative and collisional processes on the atom of interest, Li.

The collisional processes are particularly challenging. For many years following the pioneering study of \citet{1984A&A...130..319S}, the importance of inelastic hydrogen collisions was a major uncertainty.   Detailed quantum scattering calculations of Li+H collisions \citep{H+Li} and application to non-LTE modelling \citep{2003A&A...409L...1B,Lind2009} have allowed this question to be answered, and it was found that direct excitations by hydrogen collisions essentially have no influence.  However, a related charge-exchange process $\mathrm{Li(3s)} + \mathrm{H} \rightleftharpoons \mathrm{Li}^+ + \mathrm{H}^-$ was shown to be important, resulting in differences in derived abundances of about 0.05 dex in solar-metallicity stars and 0.1 dex in metal-poor stars.  Moreover, it was found that the results were not sensitive to uncertainties in the data for this process.   When the rate coefficient was altered by factors in keeping with the expected uncertainty in the theoretical calculation, the effects on the line formation were practically negligible ($< 0.01$ dex in derived abundances).

Thus, barring there being additional important collisional processes on Li we are unaware of, the uncertainties regarding collisional data lie, perhaps, with the electron collisions.  The question of quantifying these has only been touched upon briefly in the past.  \citet{1994A&A...288..860C} made calculations exploring the sensitivity of their results to various input parameters, including collision cross sections.  They identified the oscillator strengths of the lines of interest (6708 and 6104 \AA) and the photoionization cross sections from $2s$ and $2p$ as the most important atomic data in determining the uncertainties of their calculations. They estimate an error in the abundance corrections of less than 0.01 dex arising from these sources.  That the sensitivity to collisional cross sections was explored, though not discussed explicitly implies even smaller uncertainties due to collision cross sections, but details have not been published.  This study and others \citep[e.g.][]{1984A&A...130..319S, Lind2009} make use of empirically corrected calculations by \citet{1962ApJ...136..906V} and \citet{Park1971} for excitation and \citet{1976asqu.book.....A} or similar for ionization.

Given the great astrophysical importance of Li abundances and the considerable advances in calculation methods for electron scattering in the intervening period, in particular advanced close-coupling methods that are able to account for effects of coupling to the target continuum, we considered it worthwhile and prudent to accurately quantify the uncertainties associated with the electron collision data.  In this paper we examine the electron collision data in the literature, and perform a new $R$-matrix calculation, in order to accurately estimate the uncertainties in such calculations.  The data are then used in non-LTE Li I line formation modelling to assess the resulting uncertainties in stellar Li abundances.

\section{Electron collision data}

In this section we examine the existing data for excitation and ionization by electron impact used in non-LTE calculations.  We compare with advanced close-coupling calculations including our own calculations for the excitation processes and present the details.

\subsection{Excitation}

There are a number of existing calculations for electron-impact excitation $\mathrm{Li}(nl) + e \rightarrow \mathrm{Li}(n^\prime l^\prime) + e$, though only relatively recently have there been any large-scale calculations including a significant number of excited states.  Two advanced close-coupling methods have been used, namely convergent close-coupling (CCC, \citealt{PhysRevA.46.6995}) and $R$-matrix with pseudostates (RMPS, \citealt{0953-4075-29-1-015}) approaches.  The advantage of the CCC method is that, at least for collision systems with two electrons, it has been shown to yield convergent results as basis size is increased; however, it has the disadvantage of requiring considerable computational effort.  The advantage of the RMPS method is that the $R$-matrix is calculated once and then results for many collision energies can be calculated with little additional effort.  This is particularly important for the study of resonances requiring dense energy grids.  The disadvantage, however, is that convergence with basis size can be slower resulting in the appearance of pseudo-resonances.

\citet{CCC} have published data from extensive 45-state CCC calculations for transitions with $n\le 3$ and $n^\prime \le 4$, and include semi-empirical cross sections for $n=4$, $n^\prime=4$.  The calculations show good agreement with experiments where available, and analytic fits to the cross section data are provided.  \cite{Griffin2001} have done calculations using a 55-state RMPS approach resulting in cross section data for all transitions with $n=2$, $l=0$ and $n^\prime \le$ 4.  Their calculations demonstrate the importance of including the coupling to the target continuum via pseudostates, particularly at collisions energies greater than the ionization energy, i.e. $> 5.4$~eV, where the effects are small for $2s\rightarrow 2p$, but become significant for $2s\rightarrow 3l$ and even greater for $2s\rightarrow 4l$.  The cross sections are in good agreement with the CCC and experimental results where compared.  Since there is a possibility that resonances at low collision energies are unresolved by the CCC calculations and could contribute significantly to the rate coefficients, we performed our own RMPS calculations for $n \le$ 4 and $n^\prime \le$ 4 and $n^\prime l^\prime = 5s$, which gives the additional advantage of an independent check.  These calculations are described below in Sect.~\ref{sect:rmat}  and compared with the existing data in Sect.~\ref{sect:res}.

As mentioned above, the rate coefficients calculated by \citet{Park1971} have been used in most calculations of non-LTE formation of Li I lines in cool stars \citep{1984A&A...130..319S,1994A&A...288..860C, Lind2009,2010A&A...522A..26S,2005PASJ...57...45T}, so they represent an important basis for comparison in this work.  \citet{1984A&A...130..319S} replaced the data of the important $2s\rightarrow 2p$ transition with that of \citet{1962ApJ...136..906V}.  Both these sources are based on Born approximation calculations, which are well known to be valid only at high impact energies and to substantially overestimate the cross sections near threshold.  Thus, empirical corrections determined from various experiments are applied.  Based on comparison with the experiments, both works conclude that the calculated rates are not likely to be in error by more than a factor of two.

\subsubsection{R-matrix calculation}
\label{sect:rmat}

We made a 34-state RMPS calculation of the excitation by electron impacts, using existing freely available computer codes.  These calculations will now be described.

For the initial atomic structure calculations we used the code \texttt{CIVPOL}  (\citealt{civpol_thesis,CIVPOL}; see also \citealt{2004JPhB...37.2979P}), which is an adaptation of \texttt{CIV3} \citep{CIV3} that allows the construction of polarization pseudostates.  Such pseudostates are used to account for coupling to the target continuum and are needed to obtain a correct description of the dipole polarization and thus the long-range interaction potential.  They have been shown by \citet{Griffin2001} to be important at intermediate energies.  \texttt{CIV3} and \texttt{CIVPOL} use the configuration interaction (CI) method and the radial parts of the (pseudo) orbitals are represented by Slater-type orbitals; for details see \mbox{\cite{CIV3}} and \cite{CIVPOL}.
The atomic structure of the target Li I was built by optimising spectroscopic orbitals with all allowed $nl$ values up to $nl=5f$; the $1s$ and $2s$ orbitals were Hartree-Fock orbitals taken from \mbox{\cite{clementi}}.   The energies obtained for the ten lowest-lying spectroscopic states are compared with experimental values taken from the NIST Atomic Spectra Database \citep{NIST} in Table \ref{energy}, and the agreement is satisfactory.

\begin{table}
\caption{Comparison with experiment for the energies of the lowest states of Li I.}\label{energy}
\centering
	\begin{tabular}{l l c c c}\hline
   \multicolumn{2}{c}{State}         &   \multicolumn{2}{c}{Energy (Ry)}  &   \\
                                &                      &   This Work &  Experiment & Difference \\\hline\hline\\[-0.2 cm]
$1s^2$ $2s$                      &  $^2$S     &          ---          &          ---        &        ---         \\
\phantom{$1s^2$ }$2p$  & $^2$P$^\mathrm{o}$  &     0.1350      &     0.1358    &    $-$0.59\%    \\
\phantom{$1s^2$ }$3s$  & $^2$S       &     0.2474      &     0.2479    &    $-$0.20\%    \\
\phantom{$1s^2$ }$3p$  & $^2$P$^\mathrm{o}$  &     0.2807      &     0.2818    &    $-$0.39\%    \\
\phantom{$1s^2$ }$3d$  & $^2$D      &     0.2839      &     0.2851    &    $-$0.42\%    \\
\phantom{$1s^2$ }$4s$  & $^2$S       &     0.3180      &     0.3191    &   $-$0.34\%     \\
\phantom{$1s^2$ }$4p$  & $^2$P$^\mathrm{o}$  &     0.3312      &     0.3323     &   $-$0.33\%    \\
\phantom{$1s^2$ }$4d$  & $^2$D      &     0.3325      &     0.3337     &  $-$0.36\%     \\
\phantom{$1s^2$ }$4f$   & $^2$F$^\mathrm{o}$   &     0.3326      &     0.3338     &   $-$0.36\%    \\
\phantom{$1s^2$ }$5s$  & $^2$S       &     0.3479      &     0.3490     &   $-$0.32\%    \\\hline\hline
	\end{tabular}
	\tablefoot{Energies are relative to the ground state and compared with experimental values obtained from NIST data (see text). The energy difference is measured $(E_\mathrm{Theor}-E_\mathrm{Exper})/E_\mathrm{Exper}$.}
\end{table}

Once the spectroscopic orbitals (and states) were calculated, we added $n=6$($s,p,d$) and 7($s,p,d$) pseudo-orbitals to describe the polarization of the ground and first excited state, respectively. To test the quality of the polarization pseudostates, we compared the static dipole polarizabilities obtained with experimental and theoretical values found in the literature, see Table~\ref{polar}. For the polarization of the ground state there is good agreement between our results and those from the literature. In the case of the polarizability of the first excited state, we found only one other theoretical result \citep{PolThe-a}, where the polarizability is calculated in the Coulomb approximation.

\begin{table}
\caption{Dipole polarizabilities of the ground and first excited state compared with values found in the literature. }\label{polar}
\centering
	\begin{tabular}{c  c  l}\hline
	              State                 &    \multicolumn{2}{c}{Polarizability ($a_0^3$)}\\
	                                        &      This Work    &   \multicolumn{1}{c}{Other Works} \\\hline\hline
	$1s^2\,2s$ ($^2$S)       &        168.5          &   (a) 162.3, (b) {\bf 164.0(34)}    \\
                                                 &                             &   (c) 164.1 \\\hline
	$ 1s^2\,2p$ ($^2$P$^\mathrm{e}$) &        148.5           &   (a) 117.8     \\\hline\hline
	\end{tabular}
	\tablebib{(a) \cite{PolThe-a} using Coulomb Approximation; (b) \cite{PolExp} using E-H gradient balance technique; (c) \cite{PolThe-c} using CI-Hylleraas. Bold values are experimental.}
\end{table}

The computed orbitals were then used in a RMPS calculation of the electron-impact excitation cross sections.  The {\tt RMATRX I} code \citep{InnerRmatrix} was used for the internal region problem, and for the external region problem we employed a version of the code {\tt STGF} \citep{OuterRmatrix} modified for treating collisions with neutral atoms \citep{Badnell}.

After exploration of the dependence of our results on the calculation details, we finally adopted the following.  The target atom consists of 30 spectroscopic states (the ten states in Table \ref{energy} with an additional 20 spectroscopic states) and four polarization pseudostates; 34 states in total.  Target atoms with 40 and 45 states were tested and showed no significant change in the cross section results.  For both the $N$-electron and $N+1$-electron configurations, maximum occupation numbers of 2 for the spectroscopic orbitals and 1 for the pseudo-orbitals were adopted, with double excitations permitted. Calculations extending the $N+1$-electron configurations to allow all possible ways of adding one electron to the $N$-electron configurations showed no significant differences in the inelastic cross sections.  The $R$-matrix boundary between the inner and outer regions was set at 83.4 a.u.  Partial waves up to $L=50$ were calculated.

\subsubsection{Results and comparison}
\label{sect:res}

In Fig.~\ref{crossec} some of the resulting cross sections are shown, and then compared with a calculation without pseudostates, and with the fits to the CCC results of \citet{CCC}.  It is seen that the final cross sections compare well with the CCC results, particularly at low collision energies, of greatest interest for the rates at cool star temperatures.  It appears that our results are not always fully converged at intermediate energies.  For example, at collision energies above 5.4 eV, where processes involving the continuum are directly accessible, the $2s \rightarrow 3p$ cross section lies between the CCC result and the calculation without pseudostates.  \cite{Griffin2001} obtain good agreement between their somewhat larger 55-state RMPS calculation and the CCC result.  Thus, we suspect that the intermediate-energy results are not converged in this and in some other transitions; we note that this may be a result of the smaller basis size, but could also come from other details of the calculation.  However, as we will see, this is not important for calculating the rate coefficients at the temperatures and precision of interest for stellar atmosphere applications.  The behaviour within a couple of eV of threshold is far more important.  Examining Fig.~\ref{crossec} we find generally good agreement between the CCC results and ours in this region.

\begin{figure*}[t]
\centering
\includegraphics[width=0.95\textwidth]{16418fg1.eps}
     \caption{Comparison of electron-impact excitation cross sections with collision energy  for some transitions involving the lowest states of Li I.  Solid lines show our calculation using the polarization pseudo-orbitals, dashed lines are the cross sections obtained without using pseudo-orbitals, and dotted lines are the fits to the CCC calculations \citep{CCC}.}\label{crossec}
\end{figure*}

Rate coefficients were computed both from our RMPS cross sections and the CCC cross sections from \citet{CCC} by integrating the cross sections folded with a Maxwellian velocity distribution.  The rate coefficients from our RMPS calculations are presented in Table~\ref{tablerates} for a range of temperatures.  In the table the excitation rate coefficients are presented and de-excitation rates may be obtained from the detailed balance relation.    The two sets of rates are compared in the leftmost panel of Fig.~\ref{rates}, and the agreement is excellent.  This suggests that neither the inclusion of resonances nor the proper convergence at intermediate energies is vital at temperatures of interest, though we note that some cancellation may occur.  Assuming a log-normal distribution for the ratio $\langle\sigma v\rangle_\mathrm{this\,\, work}/\langle\sigma v\rangle_\mathrm{CCC}$ we find a mean of 0.83 and a scatter of 1.86; i.e. an offset of less than 20\% and a scatter of less than a factor of 2.  There is a tendency for our rate coefficients to be lower than the CCC ones for the transitions with the highest rate coefficients.  Of these seven transitions grouped with rate coefficients greater than $10^{-6}$~cm$^3$~s$^{-1}$, the one lying roughly on the one-to-one relation is $3p \rightarrow 3d$.  The remaining six transitions correspond to the $n = 4$ and $n^\prime = 4$ transitions, where, as mentioned earlier, the \citet{CCC} data are not actually CCC calculations, but semi-empirical data.  The agreement for the most important low-lying transitions (shown as different symbols) is excellent.

Our data are also compared with the data from \cite{Park1971}  and data calculated using the van Regemorter formula \citep{1962ApJ...136..906V}, the comparisons shown in the middle and rightmost panels of Fig.~\ref{rates}, respectively.   Comparison with the data of Park is generally good, although the scatter is significantly larger than seen for the CCC rates.  The Park values are typically around 40\% greater than ours, and the scatter is around a factor of 6.  It is also notable that the rate for $2p\rightarrow 3s$, corresponding to the 8126~{\AA} line, is more than 3 orders of magnitude greater in our calculations than found by Park.  The $4d \rightarrow 4f$ is the other significantly discrepant transition. The van Regemorter formula is only valid for optically allowed transitions, showing a smaller number of comparisons.  The comparison with van Regemorter has an even greater scatter than found for Park, around a factor of 18, though owing to the small number of comparisons the scatter is dominated by a small number of outliers.   The offset is slightly smaller than for the Park data.  Van Regemorter's formula gives a rate for the $2p \rightarrow 3s$ transition in much better agreement with the rate from our calculation and the CCC data, while a few other transitions show large discrepancies.

\begin{table*}
\caption{Rate coefficients for inelastic collisions between electrons and Li I atoms for different temperatures.}\label{tablerates}
\centering
{\scriptsize
	\begin{tabular}{l c c c c c c c c c}\hline
Initital   &  \multicolumn{9}{c}{Final state}\\
  state  &    2p ($^2$P$^\mathrm{o}$)     &     3s ($^2$S$^\mathrm{e}$)    &     3p ($^2$P$^\mathrm{o}$)    &  3d ($^2$D$^\mathrm{e}$)  &  4s ($^2$S$^\mathrm{e}$)     &    4p ($^2$P$^\mathrm{o}$)    &    4d ($^2$D$^\mathrm{e}$)     &      4f ($^2$F$^\mathrm{o}$)    &            5s ($^2$S$^\mathrm{e}$) \\\hline\hline \\
     & \multicolumn{9}{c}{\bf 1 000 K}  \\
 2s ($^2$S$^\mathrm{e}$)   & 2.04($-$16)  & 1.93($-$24)  & 7.55($-$27)  & 3.51($-$27)  & 1.74($-$29)  & 6.23($-$31)  & 4.79($-$31)  & 4.76($-$31)  & 3.18($-$32)  \\
 2p ($^2$P$^\mathrm{o}$)   & - -  & 8.91($-$15)  & 5.30($-$17)  & 4.72($-$17)  & 2.81($-$20)  & 4.34($-$21)  & 3.17($-$21)  & 3.08($-$21)  & 7.00($-$23) \\
 3s ($^2$S$^\mathrm{e}$)  &   & - -  & 6.34($-$09)  & 3.94($-$09)  & 7.58($-$12)  & 7.02($-$13)  & 5.47($-$13)  & 7.16($-$13)  & 2.32($-$14)\\
 3p ($^2$P$^\mathrm{o}$)   &   &   & - -  & 1.12($-$05)  & 1.42($-$09)  & 2.07($-$10)  & 1.47($-$10)  & 1.63($-$10)  & 2.05($-$12)\\
 3d ($^2$D$^\mathrm{e}$)   &   &   &   & - -  & 1.62($-$09)  & 2.59($-$10)  & 1.96($-$10)  & 2.76($-$10)  & 3.10($-$12)\\
 4s ($^2$S$^\mathrm{e}$)   &   &   &   &   & - -  & 2.14($-$07)  & 1.88($-$07)  & 2.91($-$07)  & 5.41($-$09)\\
 4p ($^2$P$^\mathrm{o}$)   &   &   &   &   &   & - -  & 3.79($-$05)  & 1.33($-$05)  & 3.58($-$08)\\
 4d ($^2$D$^\mathrm{e}$)   &   &   &   &   &   &   & - -  & 6.11($-$05)  & 4.47($-$08)\\
 4f ($^2$F$^\mathrm{o}$)   &   &   &   &   &   &   &   & - -  & 4.57($-$08)\\

   &  \multicolumn{9}{c}{\bf 2 000 K}  \\
2s ($^2$S$^\mathrm{e}$) &    8.54($-$12) & 4.78($-$16) & 2.17($-$17) & 1.57($-$17) & 7.14($-$19) & 9.99($-$20) & 9.18($-$20) & 8.61($-$20) & 1.95($-$20) \\
2p ($^2$P$^\mathrm{o}$) & - -   &    4.17($-$11) & 3.13($-$12) & 3.61($-$12) & 2.70($-$14) & 1.49($-$14) & 1.32($-$14) & 1.22($-$14) & 9.37($-$16) \\
3s ($^2$S$^\mathrm{e}$) &    &  - -  &    8.29($-$08) & 7.68($-$08) & 1.40($-$09) & 3.92($-$10) & 3.84($-$10) & 5.52($-$10) & 5.12($-$11) \\
3p ($^2$P$^\mathrm{o}$) &    &    &  - -  &    1.67($-$05) & 1.96($-$08) & 9.20($-$09) & 7.71($-$09) & 9.31($-$09) & 3.56($-$10) \\
3d ($^2$D$^\mathrm{e}$) &    &    &    & - -   &    1.96($-$08) & 8.70($-$09) & 9.01($-$09) & 1.29($-$08) & 4.56($-$10) \\
4s ($^2$S$^\mathrm{e}$) &    &    &    &    & - -   &    7.34($-$07) & 8.27($-$07) & 9.39($-$07) & 4.94($-$08) \\
4p ($^2$P$^\mathrm{o}$) &    &    &    &    &    & - -   &    5.13($-$05) & 1.40($-$05) & 1.54($-$07) \\
4d ($^2$D$^\mathrm{e}$) &    &    &    &    &    &    & - -   &    5.99($-$05) & 1.61($-$07) \\
4f ($^2$F$^\mathrm{o}$) &    &    &    &    &    &    &    & - -   &    1.40($-$07) \\

   &  \multicolumn{9}{c}{\bf 5 000 K}  \\
2s ($^2$S$^\mathrm{e}$) &    5.91($-$09) & 3.88($-$11) & 8.32($-$12) & 8.06($-$12) & 1.16($-$12) & 4.52($-$13) & 5.23($-$13) & 4.24($-$13) & 2.25($-$13) \\
2p ($^2$P$^\mathrm{o}$) & - -   &    4.97($-$09) & 1.91($-$09) & 2.62($-$09) & 7.82($-$11) & 1.00($-$10) & 1.18($-$10) & 1.06($-$10) & 1.88($-$11) \\
3s ($^2$S$^\mathrm{e}$) &    & - -   &    4.96($-$07) & 4.75($-$07) & 2.32($-$08) & 1.50($-$08) & 1.53($-$08) & 3.14($-$08) & 4.88($-$09) \\
3p ($^2$P$^\mathrm{o}$) &    &    &  - -  &    1.96($-$05) & 9.03($-$08) & 8.17($-$08) & 8.09($-$08) & 1.24($-$07) & 8.32($-$09) \\
3d ($^2$D$^\mathrm{e}$) &    &    &    & - -   &    7.26($-$08) & 5.63($-$08) & 9.24($-$08) & 1.46($-$07) & 8.44($-$09) \\
4s ($^2$S$^\mathrm{e}$) &    &    &    &    & - -   &    2.71($-$06) & 2.47($-$06) & 1.65($-$06) & 1.74($-$07) \\
4p ($^2$P$^\mathrm{o}$) &    &    &    &    &    & - -   &    5.32($-$05) & 1.14($-$05) & 5.00($-$07) \\
4d ($^2$D$^\mathrm{e}$) &    &    &    &    &    &    & - -   &    4.70($-$05) & 3.54($-$07) \\
4f ($^2$F$^\mathrm{o}$) &    &    &    &    &    &    &    & - -   &    2.20($-$07) \\

  &  \multicolumn{9}{c}{\bf 8 000 K}  \\
2s ($^2$S$^\mathrm{e}$) &    3.25($-$08) & 5.44($-$10) & 1.86($-$10) & 2.07($-$10) & 3.71($-$11) & 2.05($-$11) & 2.80($-$11) & 2.02($-$11) & 1.25($-$11) \\
2p ($^2$P$^\mathrm{o}$) &  - -  &    1.43($-$08) & 8.63($-$09) & 1.32($-$08) & 5.39($-$10) & 8.85($-$10) & 1.24($-$09) & 1.11($-$09) & 2.15($-$10) \\
3s ($^2$S$^\mathrm{e}$) &    & - -   &    9.63($-$07) & 7.18($-$07) & 4.21($-$08) & 3.76($-$08) & 3.70($-$08) & 9.52($-$08) & 1.46($-$08) \\
3p ($^2$P$^\mathrm{o}$) &    &    &  - -  &    1.86($-$05) & 1.43($-$07) & 1.42($-$07) & 1.57($-$07) & 2.75($-$07) & 1.84($-$08) \\
3d ($^2$D$^\mathrm{e}$) &    &    &    & - -   &    9.27($-$08) & 8.23($-$08) & 1.72($-$07) & 3.30($-$07) & 1.57($-$08) \\
4s ($^2$S$^\mathrm{e}$) &    &    &    &    & - -   &    4.80($-$06) & 3.37($-$06) & 1.73($-$06) & 2.43($-$07) \\
4p ($^2$P$^\mathrm{o}$) &    &    &    &    &    & - -   &    4.80($-$05) & 9.41($-$06) & 7.60($-$07) \\
4d ($^2$D$^\mathrm{e}$) &    &    &    &    &    &    & - -   &    3.90($-$05) & 4.05($-$07) \\
4f ($^2$F$^\mathrm{o}$) &    &    &    &    &    &    &    &  - -  &    2.13($-$07) \\

  &  \multicolumn{9}{c}{\bf 12 000 K}  \\
2s ($^2$S$^\mathrm{e}$) &    8.67($-$08) & 2.15($-$09) & 9.95($-$10) & 1.29($-$09) & 2.54($-$10) & 1.74($-$10) & 2.75($-$10) & 1.73($-$10) & 1.12($-$10) \\
2p ($^2$P$^\mathrm{o}$) &  - -  &    2.46($-$08) & 1.92($-$08) & 3.36($-$08) & 1.58($-$09) & 3.06($-$09) & 4.98($-$09) & 4.19($-$09) & 7.83($-$10) \\
3s ($^2$S$^\mathrm{e}$) &    & - -   &    1.56($-$06) & 8.72($-$07) & 5.99($-$08) & 6.46($-$08) & 6.32($-$08) & 1.81($-$07) & 2.62($-$08) \\
3p ($^2$P$^\mathrm{o}$) &    &    &  - -  &    1.68($-$05) & 2.01($-$07) & 2.04($-$07) & 2.44($-$07) & 4.56($-$07) & 2.86($-$08) \\
3d ($^2$D$^\mathrm{e}$) &    &    &    & - -   &    1.01($-$07) & 9.88($-$08) & 2.49($-$07) & 5.94($-$07) & 2.02($-$08) \\
4s ($^2$S$^\mathrm{e}$) &    &    &    &    & - -   &    7.10($-$06) & 4.04($-$06) & 1.69($-$06) & 3.08($-$07) \\
4p ($^2$P$^\mathrm{o}$) &    &    &    &    &    & - -   &    4.19($-$05) & 7.77($-$06) & 9.94($-$07) \\
4d ($^2$D$^\mathrm{e}$) &    &    &    &    &    &    & - -   &    3.24($-$05) & 4.12($-$07) \\
4f ($^2$F$^\mathrm{o}$) &    &    &    &    &    &    &    &  - -  &    1.90($-$07) \\

    & \multicolumn{9}{c}{\bf 20 000 K}  \\
2s ($^2$S$^\mathrm{e}$) &    1.98($-$07) & 6.10($-$09) & 3.74($-$09) & 5.91($-$09) & 1.18($-$09) & 9.68($-$10) & 1.78($-$09) & 9.36($-$10) & 5.96($-$10) \\
2p ($^2$P$^\mathrm{o}$) &  - -  &    3.79($-$08) & 3.65($-$08) & 7.77($-$08) & 3.74($-$09) & 8.49($-$09) & 1.62($-$08) & 1.20($-$08) & 2.00($-$09) \\
3s ($^2$S$^\mathrm{e}$) &    & - -   &    2.53($-$06) & 9.79($-$07) & 8.74($-$08) & 1.03($-$07) & 1.03($-$07) & 2.99($-$07) & 4.06($-$08) \\
3p ($^2$P$^\mathrm{o}$) &    &    &  - -  &    1.39($-$05) & 2.91($-$07) & 2.94($-$07) & 3.85($-$07) & 7.01($-$07) & 4.07($-$08) \\
3d ($^2$D$^\mathrm{e}$) &    &    &    & - -   &    1.01($-$07) & 1.11($-$07) & 3.40($-$07) & 1.06($-$06) & 2.18($-$08) \\
4s ($^2$S$^\mathrm{e}$) &    &    &    &    & - -   &    1.01($-$05) & 4.59($-$06) & 1.56($-$06) & 4.02($-$07) \\
4p ($^2$P$^\mathrm{o}$) &    &    &    &    &    & - -   &    3.36($-$05) & 5.95($-$06) & 1.24($-$06) \\
4d ($^2$D$^\mathrm{e}$) &    &    &    &    &    &    & - -   &    2.50($-$05) & 3.90($-$07) \\
4f ($^2$F$^\mathrm{o}$) &    &    &    &    &    &    &    &  - -  &    1.52($-$07) \\

   & \multicolumn{9}{c}{\bf 50 000 K}  \\
2s ($^2$S$^\mathrm{e}$) &    4.59($-$07) & 1.60($-$08) & 1.23($-$08) & 2.55($-$08) & 4.36($-$09) & 4.11($-$09) & 9.07($-$09) & 3.49($-$09) & 2.10($-$09)\\
2p ($^2$P$^\mathrm{o}$) &  - -  &    6.40($-$08) & 6.89($-$08) & 2.08($-$07) & 7.82($-$09) & 2.03($-$08) & 4.91($-$08) & 2.74($-$08) & 3.73($-$09) \\
3s ($^2$S$^\mathrm{e}$) &    & - -   &    4.25($-$06) & 1.00($-$06) & 1.43($-$07) & 1.53($-$07) & 1.61($-$07) & 3.95($-$07) & 5.35($-$08) \\
3p ($^2$P$^\mathrm{o}$) &    &    &  - -  &    8.96($-$06) & 4.60($-$07) & 4.34($-$07) & 6.67($-$07) & 9.68($-$07) & 5.58($-$08) \\
3d ($^2$D$^\mathrm{e}$) &    &    &    & - -   &    8.45($-$08) & 1.08($-$07) & 4.28($-$07) & 1.97($-$06) & 1.74($-$08) \\
4s ($^2$S$^\mathrm{e}$) &    &    &    &    & - -   &    1.28($-$05) & 4.57($-$06) & 1.24($-$06) & 5.48($-$07) \\
4p ($^2$P$^\mathrm{o}$) &    &    &    &    &    & - -   &    2.10($-$05) & 3.54($-$06) & 1.37($-$06) \\
4d ($^2$D$^\mathrm{e}$) &    &    &    &    &    &    & - -   &    1.50($-$05) & 3.11($-$07) \\
4f ($^2$F$^\mathrm{o}$) &    &    &    &    &    &    &    & - -   &    8.78($-$08) \\
\hline \hline
	\end{tabular}
	\tablefoot{Rate coefficients, $\langle\sigma v\rangle$, are given in cm$^3$ s$^{-1}$.  The values should be read as: $a(b) := a \times 10^b$.}
	}
\end{table*}

The non-LTE line source function for the very important 6708~{\AA} resonance line is described well by a two-level approximation \citep{1994A&A...288..860C}, and thus the data for $2s \rightarrow 2p$ are of special interest.  The data are compared in Table~\ref{tab:2s2p} and all four calculations are in reasonable agreement, though the \citet{Park1971} value is roughly a factor of two larger than the other three.

\begin{table}
\caption{Comparison of the rate coefficient $\langle \sigma v \rangle$ for the transition $2s \rightarrow 2p$ at 8000 K.}\label{tab:2s2p}
\centering
 \begin{tabular}{cc}
 \hline
 Method   & $\langle \sigma v \rangle$ (cm$^3$ s$^{-1}$) \\\hline\hline
    This Work           &    3.28($-08$)   \\
   \cite{CCC}          &   3.33($-08$)   \\
   \cite{Park1971}  &  6.36($-08$)   \\
   \cite{1962ApJ...136..906V}      &  2.46($-08$)   \\
   \hline \hline
 \end{tabular}
\end{table}

\begin{figure*}
\centering
\begin{tabular}{c c c}
\includegraphics[width=0.31\textwidth]{16418f2a.eps}&\includegraphics[width=0.31\textwidth]{16418f2b.eps}&\includegraphics[width=0.31\textwidth]{16418f2c.eps}\\
\end{tabular}
\caption{Rate coefficients at 8000 K obtained by us compared with those calculated from the CCC calculations \cite[left]{CCC}, those of \cite[middle]{Park1971} and those calculated using the van Regemorter formula \citep{1962ApJ...136..906V}.  The latter is only valid for optically allowed transitions, hence the limited number of comparison points. The different symbols are for the rate coefficients corresponding to the transitions: \mbox{$2s \rightarrow 2p$ [ {\Large $\diamond$}, 6708 \AA\ ]}, \mbox{$2p \rightarrow 3d$ [ $\square$, 6104 \AA\ ]}, and \mbox{$2p \rightarrow 3s$ [ $\Delta$, 8126 \AA\ ]}. }\label{rates}
\end{figure*}

\subsection{Ionization}

Regarding electron-impact ionization $\mathrm{Li}(nl) + e \rightarrow \mathrm{Li}^+ + 2e$, \citet{CCC} have also calculated cross sections via the CCC method for the $2p$ and $n = 3$ states. For ionization cross sections from the ground state ($2s$) calculations by \cite{lennon:1285} are recommended by \cite{CCC}.  The results of CCC and RMPS calculations for this process where $n=2$ have been shown to be in good agreement \citep{2001PhRvL..87u3201C}.  Thus, since this process is likely to be less important in this application, we adopted the CCC data directly.  As mentioned, non-LTE calculations have typically used a semi-empirical formula from \citet{1976asqu.book.....A} based on a fit to experimental data \citep[see][]{1962amp..conf..375S}.   A comparison of cross sections from the semi-empirical formula with those of \citet{CCC} is presented in Fig.~\ref{ioncrossec}.   The comparison shows a tendency for the ionization cross sections of the semi-empirical formula to be significantly  larger than the CCC results.   Rate coefficients calculated by integration over a Maxwellian velocity distribution are presented in Table~\ref{tab:ion}.

\begin{figure*}[t]
\centering
	\begin{tabular}{c c c}
\includegraphics[width=0.95\textwidth]{16418fg3.eps}
	\end{tabular}
     \caption{Comparison of electron-impact ionization cross sections with the collision energy for the lowest states of Li I. The solid lines show cross sections from \cite{lennon:1285} and the CCC calculations \citep{CCC} (see text).  The plus signs are those calculated from the semi-empirical formula \citep{1976asqu.book.....A}.}\label{ioncrossec}
\end{figure*}

\begin{table*}
\caption{Rate coefficients for collisional ionization between electrons and Li I atoms for different temperatures. }
\label{tab:ion}
\centering
	\begin{tabular}{l c c c c c c c}\hline
Bound & \multicolumn{7}{c}{Temperature (K)} \\
State     &   1 000  &    2 000 &      5 000 &      8 000 &      12 000 &      20 000 &      50 000 \\\hline\hline\\
2s($^2$S$^\mathrm{e}$) &   4.85($-$36) & 3.00($-$22) & 8.63($-$14) & 1.35($-$11) &  2.46($-$10) &  2.73($-$09)  & 2.69($-$08) \\[0.1cm]
2p($^2$P$^\mathrm{o}$) & 5.53($-$26)  & 6.19($-$17) & 2.06($-$11)  & 5.49($-$10)  & 3.62($-$09)  & 1.76($-$08) & 8.23($-$08) \\[0.1cm]
3s($^2$S$^\mathrm{e}$) & 1.03($-$17) & 1.57($-$12) & 2.34($-$09)  & 1.55($-$08)  & 4.55($-$08)  & 1.11($-$07) & 2.44($-$07) \\[0.1cm]
3p($^2$P$^\mathrm{o}$) & 3.10($-$15) & 3.03($-$11) & 8.07($-$09) & 3.45($-$08) & 8.07($-$08)  & 1.67($-$07) &  3.36($-$07) \\[0.1cm]
3d($^2$D$^\mathrm{e}$) &  7.00($-$15) & 5.43($-$11) & 1.25($-$08) & 5.11($-$08) & 1.16($-$07) & 2.33($-$07) & 4.30($-$07) \\ \\\hline\hline
	\end{tabular}
\tablefoot{The rate coefficients $\langle\sigma v\rangle$, in cm$^3$ s$^{-1}$, are calculated from the ionization cross sections from \cite{lennon:1285} and \cite{CCC} (see text).  The values should be read as: $a(b) := a \times 10^b$}
\end{table*}

\section{Application to non-LTE Li I line formation }

The most commonly observed lines for Li I in stellar spectra are those corresponding to the $2s$-$2p$ and the $2p$-$3d$ transitions at 6708 \AA\ and 6104 \AA , respectively. In Li-rich stars the 8126~\AA\ line is also observed \citep{8126lineA,8126lineB}, this line corresponding to the transition $2p$-$3s$.  It has also been suggested that this line might be visible in other Li-rich objects such as chemically peculiar stars \citep{1999A&A...351..283P}, though we are not aware of any such detections.

Previous non-LTE calculations of Li line formation in cool stars by \cite{1994A&A...288..860C} and \citet{Lind2009} used the rate coefficients of \cite{Park1971} for the description of the electron-impact excitation in their model atom and the recipe of \citet{1976asqu.book.....A} for ionization.  \citet{1984A&A...130..319S} also used the Park data, but replaced the value for the $2s$-$2p$ transition with the van Regemorter value.  A similar semi-empirical recipe for the ionization is also used.  Thus, the three works that are of most interest for comparison use essentially the same electron collision data.   In this work we used the same model atom as \citet{Lind2009}, changing only the electronic collision data; that is, the rate coefficients of Tables~\ref{tablerates} and \ref{tab:ion} replace the old data for excitation and ionization by electron impact.  The collision rates from \cite{Park1971} for the transitions involving high-lying levels not covered by our calculations were retained.   We calculated non-LTE corrections for a range of stellar atmospheric models using the old and new model atoms.  Some example comparisons of the results are shown in Fig.~\ref{acorr}.   We found the differences between the two model atoms to be $<0.01$ dex for solar-type stars. In warm stars, $T_\mathrm{eff}>7000$~K, the differences are slightly larger but still $\la 0.02$\,dex.

\begin{figure*}
\centering
	\begin{tabular}{l c r}
	\includegraphics[width=0.33\textwidth]{16418f4a.eps}&  &  \includegraphics[width=0.33\textwidth]{16418f4b.eps} \\
	&&\\
	\includegraphics[width=0.33\textwidth]{16418f4c.eps}& & \includegraphics[width=0.33\textwidth]{16418f4d.eps}
	\end{tabular}
\caption{Non-LTE Li abundance corrections for the 6707~\AA\ resonance line using the model atom as \cite{Lind2009} and replacing the e+Li collisions from \cite{Park1971} (dashed line) with the new calculations (solid line). The dotted line shows the zero value. In the lower left corner of each plot are the stellar parameters of the model used: \mbox{$T_\mathrm{eff}$/log $g$/[Fe/H]}.}\label{acorr}
\end{figure*}

The behaviour of the abundances measured using the 6104~\AA\ and  8126~\AA\ spectral lines was also studied. The transition  $2p$-$3s$, corresponding to the 8126~\AA\ line, has the largest difference in the rate coefficients when compared with those from \citet{Park1971}.  For all the atmospheric model cases shown in Fig.~\ref{acorr}, the Li abundance derived from this line shows very similar sensitivity to the new electron collision data.  The effects of the new electron collision data on the abundance measured from the 6104~\AA\ line are considerably less in the solar case: only about 10\% of the difference shown by the other two lines.  In the other cases the influence of the electron collision data on the abundance measured from the 6104~\AA\ spectral line is again comparable to the influence on the 6708 and 8126~\AA\ lines.

\section{Conclusions}
A common problem for calculating non-LTE abundance corrections is that they can be subject to errors from uncertainties in the underlying atomic data.   We have shown that electron collision data from a number of different calculations based on quite different methods are in good or even excellent agreement.  Data calculated with advanced close-coupling techniques provides data in excellent agreement, giving rate coefficients for excitation processes within a factor of 2 for the temperatures of most interest in cool stellar atmospheres, $T \sim 5000$ -- 8000~K.  This, and the good agreement with experimental results where available \citep[see][]{CCC}, suggests the data have an uncertainty of similar magnitude.   The semi-empirical data for both excitation and ionization that have been commonly used in non-LTE calculations for Li up to now, agree reasonably with the modern data, generally agreeing within a factor of 6, though with a few significant outliers.  This suggests that the estimates of the uncertainties of a factor of 2 for these data are somewhat too low, though the data for the important $2s$-$2p$ transition does indeed agree within a factor a two.

We find that these uncertainties are not very important when applied to Li I in cool stars, and the differences typically result in uncertainties of less than 0.01 dex.  The strongest effects are found in F dwarfs and extremely Li-rich stars.  These uncertainties are certainly negligible compared to those arising from other sources, especially the atmospheric modelling \citep{2005ARA&A..43..481A}.
Thus, we conclude that the existing electron collision data, or the data presented in this paper, when coupled with data for the charge exchange process $\mathrm{Li(3s)} + \mathrm{H} \rightleftharpoons \mathrm{Li}^+ + \mathrm{H}^-$ now available, are accurate enough to reliably model non-LTE formation of Li lines in stellar atmospheres at the 0.01~dex ($\sim 2$\%) level.

\begin{acknowledgements}
We thank Martin Plummer for providing us with an optimised copy of the \texttt{CIVPOL} code.  We gratefully acknowledge the support of the Royal Swedish Academy of Sciences, G{\"o}ran Gustafssons Stiftelse, and the Swedish Research Council.  Y.O.\ is grateful for hospitality and financial support during a visit to the Max Planck Institute for Astrophysics, Garching. P.S.B.\ is a Royal Swedish Academy of Sciences Research Fellow supported by a grant from the Knut and Alice Wallenberg Foundation.
\end{acknowledgements}

\bibliographystyle{aa}

redpajama_set_name: RedPajamaArXiv


Feeling overwhelmed, stressed, or a little lost in a specific area of your life? Might be time to outsource or hire some help!
In this week's episode, Ben and I discuss the ways in which we have both (individually and as a couple) recently asked for help and gotten it; I go into a little more depth about hiring Sara (who I introduced to you a few weeks ago), and Ben shares his experience "outsourcing" his physical training for the first time in a couple of years.
In chatting about both of these instances and a few other recent examples, we cover how this help has changed our lives for the better and delve into some of the factors to consider when deciding whether or not to outsource tasks or projects in your life.


Be aware of these symptoms of head and neck cancer, and know when to seek medical attention.
A hoarse voice or persistent sore throat that lasts for weeks may seem like a mild nuisance, but those same symptoms could be early signs of head and neck cancer.
In the past, head and neck cancer was usually diagnosed in older patients with a history of tobacco or heavy alcohol use, but today younger patients are developing the disease because they have acquired the human papilloma virus. This sexually transmitted virus is quite common and is usually shed by the body with no long-term effects. However, in some patients the HPV infection persists and the virus can cause head and neck cancers in men and women and cancer of the cervix among women.
The National Cancer Institute lists symptoms of head and neck cancers as including a lump or a sore that does not heal, a sore throat that does not go away, difficulty in swallowing, and a change or hoarseness in the voice.
It's important to remember that these symptoms may also be caused by other, less serious conditions, and to always check with your doctor or dentist if you develop these symptoms.
Oral cavity. A white or red patch on the gums, the tongue or the lining of the mouth; a swelling of the jaw that causes dentures to fit poorly or become uncomfortable; and unusual bleeding or pain in the mouth.
Tobacco use is a risk factor for head and neck cancer, and quitting is one of the best things you can do for your health if you're a smoker. Find resources about how to kick the habit here.
Dagny Stuart is an information officer for Vanderbilt University Medical Center.
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text:
Josephus Guilelmus Soussé (né à Anvers en 1676 et mort dans la même ville en 1752) est un prêtre, chanteur puis maître de chant dans plusieurs églises anversoises.

Soussé a d'abord été ténor à l'église Saint-Jacques d'Anvers de 1707 à 1711, puis maître de chant (zangmeester) à l'église Saint-André d'Anvers de 1711 à 1718, avant de retourner à Saint-Jacques comme maître de chant jusqu'à sa mort. Il eut comme chanteur et élève Henri-Jacques De Croes qui fut admis en 1716 à Saint-André. Les deux hommes se retrouveront à Saint-Jacques où De Croes fut premier violon de 1723 à 1729. Soussé souscrira à l'opus IV (Bruxelles 1737) de son ancien élève et premier violon. Un an après sa mort, la collection musicale de Soussé est mise aux enchères.

Bibliographie
  Stefanie Beghein, Kerkmuziek, consumptie en confessionalisering. Het muziekleven aan Antwerpse parochiekerken, c. 1585-1797, thèse de doctorat, Université d'Anvers, 2014 Lire en ligne,
 Godelieve Spiessens, « Nieuwe biografische gegevens over Henri-Jaques De Croes », Adem, XXIII, pp. 11-13, 1986.

Notes et références

Prêtre catholique belge
Naissance en 1676
Naissance à Anvers
Décès en 1752
Décès à Anvers