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Popular Science Monthly/Volume 41/August 1892/Popular Miscellany
< Popular Science Monthly | Volume 41 | August 1892
Publications Received
Popular Science Monthly Volume 41 August 1892 (1892)
1216675Popular Science Monthly Volume 41 August 18921892
POPULAR MISCELLANY.
Anthropology at the World's Fair.—Prof. F. W. Putnam, the distinguished anthropologist of Cambridge, Mass; has outlined a most attractive and important exhibit of anthropology at the World's Fair. The department will occupy the northern half of the gallery of the Main Building and also a strip of land along the lagoon; on this land groups of native American peoples will be living in their natural habitations and surroundings. There will be a representative exhibit of the remains of prehistoric man in America, and large models of the most noteworthy of their works, such as the Serpent Mound and Fort Ancient. Central America will be well represented. Along with this there will be an exhibition of primitive industries, customs, and the like. The section of physical anthropology will illustrate modern methods of recording bodily characteristics, and will show charts recording the results of many thousand measurements. A large body of workers are now engaged in measuring native Americans in all parts of the land. Measurements of children are also being gathered for the study of the development of physical characteristics. This is a large and important undertaking, from which results of great scientific value are sure to come. With this department there is also connected the department of history, so that the exhibit of primitive man and his works is followed by that of the men whom Columbus met, and thus prepares the way for the exhibit of the historical changes in America during the last four centuries. The comprehensive scope of the exhibit is noteworthy, and under the leadership of Prof. Putnam an exhibit creditable to American science is assured.
Experimental Psychology at the World's Fair.—Those who have been interested in the growth of the new psychology will be glad to learn that there will be made at the World's Fair an exhibit of the methods and results of this young science. There will be in operation throughout the six months of the exposition a psychological laboratory in which simple tests will be made of the senses, sense-judgments, rapidity of movements, and simple mental processes, memory, and so on; the data thus accumulated will be statistically utilized to obtain normal standards. There will also be exhibited apparatus employed in psychological research, results obtained, as illustrated by charts, diagrams, photographs, etc.; and as complete a representation of recent psychological activity as the facilities will admit. The department is in charge of Prof. Joseph Jastrow, of the University of Wisconsin, and is a part of the general department of which Prof. F. W. Putnam is chief.
A Portrait of William Bartram.—When the sketch of the Bartrams was published in the April number of the Monthly, we were not able to find any authentic portrait of either of them, or to learn that any existed. The publication of the sketch called out from Dr. W. H. Mills, of Syracuse, N. Y., the information that an engraved portrait of William Bartram was in existence, and formed the frontispiece to the second volume of the Cabinet of Natural History and American Rural Sports, published in Philadelphia in 1832 by J. & T. Dougherty. Through the kindness of Dr. Mills we have been able to procure this volume, and to have a copy made of this picture. Concerning the authenticity of the portrait, the statement is made in the Biographical Sketch of William Bartram, which is the first article in the volume, that "the accompanying portrait is a correct likeness of Mr. Bartram, and the only engraved one ever given to the American public." It will be observed that the date of the publication of this portrait was only nine years after Mr. Bartram's death.
WILLIAM BARTRAM.
The Schools of New York State.—According to the Report of State Superintendent Draper, while the number of children of school age in the State of New York appeared to be 22,823 less than in 1890, the number of children in attendance on the public schools (1,054,044) was greater by 11,884. Besides these, the private schools reported an attendance of 157,603, and the normal schools, academies, colleges, etc., 69,392 pupils of school age in 1891. Comparative tables of attendance show a steady increase in cities (270,926 to 513,066) since 1861, while the attendance in towns has fallen from 601,928 to 540,978. The superintendent calls attention to the insufficiency of the laws for compulsory attendance, and in view of crude features in the laws of some other States, he recommends the formation of a State Educational Commission, with sufficient powers to consider the whole subject of the school laws of the State. In view of the weakness of some of the school districts, the superintendent favors the consolidation of small and weak districts when it can be brought about without serious inconvenience to the children of school age. It is not to be overlooked, however, that the school must be at a convenient distance. In Massachusetts provision is made for the transportation of children to distant schools, and profitless schools have been abolished, while the children are now instructed for a longer term under teachers of more experience and skill. The superintendent recommends the township system of school organization for consideration. An increasing interest in Arbor Day is noticed. The celebrations are usually marked by appropriate literary exercises, with many ingenious and elaborate programmes. Interest in this work has been stimulated by the offer, by Mr. William A. Wadsworth, of prizes for the best-kept school-grounds. The vote upon the question of a State flower has resulted in a majority for the rose over the golden-rod. The attempt to provide textbooks to be published by the State has resulted disastrously wherever it has been made. The superintendent thinks that the result of such a policy would be bad, even if it were seemingly successful. It would discourage authorship, discontinue competition among makers, and stop the constant improvement in the matter, style, and character of the books which has been marked in the past.
Barrel-making.—Few people, says Chambers's Journal, though all are familiar with the barrel, have probably been at pains to consider the skill and ingenuity which have succeeded in bringing to perfection an invention as scientific as beneficial all the world over; and probably fewer still are conversant with the brain-power and time which have been expended in attempts to produce machinery for manufacturing them. Barrels were in use as far back as the time of Pliny, who says they were invented in the Alpine valleys. A cask is a double conoid that is, it has its greatest diameter or its bulge or belly in the center. The stave is curved lengthwise to form the bulge and crosswise to form part of the circumference of the cask; while the edges must receive the exact bevel to fit those on either side along their entire length. Then the staves have to be "chimed" or beveled at the ends, and furnished with a "croze" or groove, into which to fit the heads; and hooping completes the manufacture of the cask. A new invention, by a Mr. Oncken, is in full operation at Merxem, in Germany, for turning out casks from one piece of wood. In the process the stem of a tree is cut into lengths corresponding to the size of the cask. These lengths are then boiled for two or three hours in a closed vessel, while a current of electricity is passed through the water. The wood is thereby softened so that it can be cut, in a machine rotating the log in the same manner as the ordinary lathe, into a sheet of any desired thickness. The sheets are then passed through a grooving machine and grooved. Another machine seizes the sheet between two arms, and by means of knives cuts a series of mortices or slots around the sides, so as to give them, when made up, the desired conical shape. Eventually the sheet reaches the cooper, who rolls it into cylindrical form, drives on the hoops, and makes a barrel of it.
The Chemung Geological Formation.—The conclusions of Prof. John J. Stephenson's review of the relations of the Chemung and Catskill formations on the eastern side of the Appalachian basin, as expressed in his address at the American Association, are that the series from the beginning of the Portage to the end of the Catskill forms but one period, the Chemung, which should be divided into three epochs the Portage, the Chemung, and the Catskill; that the deposits of the Catskill epoch were not made in a closed sea or in fresh-water lakes; that the disappearance of animal life over so great a part of the area toward the close of the period was due to gradual extension of the conditions existing in southeastern New York as early, perhaps, as the Hamilton period; and that the Chemung period should be retained in the Devonian.
Scenery of the Mustagh Glaciers.—In his description, before the English Society of Arts, of the Pamirs and neighboring regions, Captain F. E. Younghusband gave a picturesque account of the scenery of the glacial regions of the Mustagh Mountains. The first object to attract attention in ascending the mountain streams is the appearance of what seem to be great heaps of gravel, with a stream issuing from their feet. Clambering up to the summit of one of these mounds, the traveler looks upward over a sea of needle-like pinnacles of ice, of every fantastic shape and variety of color, and among them sees long lines of rocky débris, the medial moraines of the glacier, "while on either hand mountains of stupendous height rise in stern and solemn glory." Among the pinnacles, or serecs of ice, "may be seen fairy-like caves and grottoes of pure ice, with icicles twenty or thirty feet in length hanging from the ceiling or formed in a delicate fringe across the entrance, and into the walls of these lovely caves one can look as into a sheet of glass." When the great snow-fields at the head of the glacier are reached, "all is white, pure, and unblemished; and the bold intruder is deeply and unforgetablyimpressed with the noble sublimity of the mountains towering round on every hand, and moved by his audacity in daring to intrude into regions ruled by Nature in such stern and silent grandeur. He feels, too, what tremendous forces are at work beneath the calm and placid surface; for, while at first sight all seems still and unchangeable, a glance around shows the glaciers rent into great chasms with perpendicular walls of ice, perhaps hundreds of feet deep, into which, if a stone is dropped, it bounds from side to side, and the echoes are heard coming up from the very heart of the glacier. And then a little observation shows that these vast seas of ice, motionless and immovable as they seem, are year by year forcing their way down the valleys, carrying on their icy bosoms the fragments and craigs of rock which have been broken off from the mountains by the nipping fingers of the frost. Great cliffs, too, are met with, worn away and ground by the glacier forced against them; and I have seen a whole cliff of limestone polished and smoothed by the glacier almost as well as small fragments of rock are by the hand of man."
Eastern and Western Weeds.—A comparative list has been published by Prof. Byron D. Halsted, made up from his own observations and those of his correspondents, of the weeds of New Jersey or the East, and Iowa or the central West. Of 297 weeds in Iowa, 210 are native and 87 are foreign; and they are further classified as 51 worst weeds, 94 bad weeds, and 152 indifferent weeds. In passing from the worst weeds through the middle class to the indifferent, the percentage of perennials rapidly increases. In New Jersey, 135 weeds are native and 130 are foreign; and 55 are worst, 98 are bad, and 112 are indifferent, The weeds in Iowa not found in New Jersey are mostly of the indifferent class, native in large part of the prairie, and as a rule quickly disappear when the land is placed under cultivation. The New Jersey list can be made up from the one for Iowa by omitting 75 of the native prairie plants, mostly perennials, and adding 43, a large percentage of which are annuals. The only single weed of the first rank stricken from the Iowa list in adapting it for New Jersey is a species of pigweed, but even this has within a year been found in New Jersey. On the other hand, there are several first-class (worst) weeds that are added in the adaptation of the Western list to the East. Of such, for example, are a pepper-grass, the wild radish, two kinds of cocklebur, feverfew, wild onion, wild leek, nut-grass, Bermuda grass, and a kind of chess. The East is overrun with a larger number than the West of the most aggressive weeds "weeds that assert their ability to resist the forces of the cultivator and plant their banners upon the tilled ground, likewise annual weeds that stock the soil with a multitude of seeds, ready to spring into life whenever an opportunity offers. Some species of weeds, such as a goose-foot, a pigweed, a thistle, plantain, shepherd's-purse, and purslane, are found everywhere from Maine to California; others are prominent on the Pacific coast and not elsewhere; and there are weeds peculiar to the Rocky Mountain region, and others to the prairie region. In the middle prairie States it is mostly the members of the sunflower family that prevail. In the central States the list is led by the Canada thistle, quack-grass, docks, daisy, chess, plantain, and purslane. If to this list we add wild carrot, onion, and parsnip, and the like old foreign enemies, we have the extensive catalogue of these plant pests that prey upon the lands of New England.
Hypnotism as a Remedy.—Accounts are given by Dr. George C. Kingsbury, in his Practice of Hypnotic Suggestion, of fifty cases of pain or disease which he has himself treated by hypnotism. In forty-five of these, complete cure followed, without any relapse so far as is known, and there was at least some slight or temporary relief in the five others. In one case the hypnotism was used as an anæsthetic in childbirth. The patient was hypnotized twelve times in preparation for her confinement, and once more when it began. She was brought to the convenient stage of hypnotic somnambulism in which she could understand and obey orders and nevertheless felt no pain. In the treatment of three patients of confirmed drunken habits some remarkable results in the way of sobriety, or even dislike for alcohol, were obtained, which had lasted up to the time of the publication of the book, nine months or more, and none of them was known to have relapsed. In many lesser ills, such as neuralgia, headache, toothache, etc., the relief of the pain was immediate and complete. The author has found no damage done by hypnotism in careful hands.
The Weather and Influenza.—A paper by Dr. Lang, of Munich, treats of the relations between influenza and changes of weather. Among atmospheric conditions favorable to the development of infectious maladies are light and rare precipitations, while the soil dries out and dust abounds, and next slight winds. Such conditions prevail in anti-cyclones. But not every barometric maximum that occurs can be accused of being a promoter of an epidemic. The germs of the disease must be present, then the anti-cyclone is a danger. Entirely local conditions can not be held to account for what passes in the atmosphere, nor for events that depend on its constitution, for the air is not, like us, fixed to the ground. It is continually suffering displacement, and brings us elements from all the places over which it has passed. We must look, therefore, to the place where the wind started that is, to the center of the aerial circulation of the region in which we are. We know that the distribution of barometric pressure is a determining cause of the movements of the air, and it may be that the corpuscles scattered through the atmosphere have been brought from far-off regions, especially if the distribution of the pressure has continued the same during a considerable time. In the winter of 1889-'90 a barometric maximum was fixed for six weeks in the eastern part of Europe, with only unimportant modifications in its shape and extent. Now, since the East included the starting-point of the epidemic of influenza that prevailed then, it is presumed that this atmospheric condition favored its extension toward the West. The views expressed by M. Masson, of Paris, before one of the medical societies of that city, substantially agree with these. The period of greatest mortality from grip in Paris, from November, 1889, to February 1, 1890, was marked by a constantly higher pressure than the average; the temperature did not fall below 5 C.; the hygrometric condition was high, and radiation fell off from the very beginning of the epidemic. In the principal capitals of Europe, according to M. Masson's investigations, the grip coincided in general with a humid, foggy condition of the atmosphere, and only moderate cold and an unusual height of barometer. It was so at Vienna, Berlin, and Brussels. But in Russia, where the grip is endemic, the mortality increased when the barometer fell and the thermometer rose, and the mean humidity was augmented. At St. Petersburg it disappeared when the pressure rose and the cold became more intense. For all other regions M. Lang's and M. Masson's rules were verified.
The Parapee Palm.—According to a note in Garden and Forest, the Parapee palm (Guiliehna speciosa) is cultivated by the Indian aborigines of the Guianas for its fruit, which they use largely as food. They plant it about their settlements, and, where it is found apparently wild in the forests, examination will show that such situations were formerly occupied by the Indians. In some seasons the fruit is produced without seed, while in other seasons it contains seeds, the variation occurring in the fruit of the same trees from season to season. When boiled or roasted the fruit has something of the texture and taste of a dry, mealy potato. It is palatable and very nutritious. The fruits, which are individually about the size of a pigeon's egg, are borne in bunches of from forty to sixty together. There are two or three bearing seasons in a year.
Preservation of Minerals and Fossils.—Minerals and fossils are not exposed to the ravages of insects, like zoological collections; but many of them are liable to destruction by deliquescence and efflorescence. Deliquescence is the property possessed by some bodies of attracting moisture from the atmosphere and dissolving in it. There is no means of preventing these accidents, except inclosing the specimens in hermetically sealed envelopes. Efflorescence is a property possessed by other bodies of falling into powder. There are several ways of protecting specimens against it. Fossils converted into white pyrites, or the substance of which is impregnated with salts and not susceptible of being washed, should be fully dried and covered with a varnish that will not scale, and they can also be dipped in oil. Impressions in danger of being rubbed off can be consolidated by impregnating them with a thin solution of gum arabic, a little sugared to prevent its cracking. Mr. Chalande recommends for the preservation of rocks, fossils, bones, etc., liable to split or fall into efflorescence, placing them for from one to twenty-four hours, as the case may demand, in a bath, made by mixing equal parts of silicate of soda or potash and water, and drying after the bath. This gives the piece a considerable degree of hardness. For the preservation of pyritous fossils, M. Andre Fonville recommends preservation in paraffine; this, however, is only adapted to small specimens; and for fossils of considerable size, like ferns, sigillaria, etc., he advises the silicate-of-soda method. To consolidate fossil bones, M. Lambert recommends coating with boiling melted whalebone. The hot matter penetrates the pores and becomes very hard. If any of it remains on the outside of the specimen, it may be removed with blazing paper. Gelatine and strong glue, used by many persons, are good, but not so good as the whalebone application.
The "Silver Thaw."—The "silver thaw," as described by R. C. Mossman, of Ben Nevis Observatory, occurs during an inversion of ordinary temperature conditions, when the temperature is considerably lower at the surface than at higher altitudes, and the rain congeals as it falls. In the six years from 1885 to 1890, 198 cases of silver thaw were observed at Ben Nevis, with a mean duration of four hours and a half in each case. They nearly all occurred between November and March, during times of perfectly developed cyclones and anti-cyclones. Ninety per cent of the cases occurred when the thermometer was between 28° and 31·9°, so that the greater number of cases occurred just before a thaw. The most common type of cloud which preceded both cyclonic and anti-cyclonic cases of silver thaw was cirrocumulus, frequently accompanied by cirrus and cirro-stratus; and the changes showed that the higher strata of the atmosphere came first under the influence of the moist current, which took from three to eight hours to descend to the height at which cumulo-stratus forms.
Our Destructive Locusts.—Eight kinds of destructive locusts are described in Prof. C. V. Riley's paper on that subject as infesting the United States or parts of its territory. The first is the Rocky Mountain locust (Caloptenus spretus), which has caused great destruction at times in its sudden, temporary appearances in the Western States and Territories. Its permanent breeding-ground, where it breeds every year and is always to be found in greater or less numbers, embraces the larger part of Montana, a narrow strip of western Dakota, all but the northwestern quarter of Wyoming, the central and northwestern parts of Colorado, small tracts in Utah, Oregon, and Idaho, and a large area in the British possessions north of Montana. The subpermanent region, where it is liable to breed for a few years and then disappear, lies immediately east of this; and the temporary region, where it appears for single seasons, includes large territories east and south of the subpermanent region. The lesser migratory locust (Caloptenus atlantis) breeds annually in abundance from middle Florida nearly to the Arctic Circle. It has been marked as injurious in New England in nineteen seasons since 1743. The nonmigratory red-legged locust (Caloptenus femur rubrum) has a common range with the previous species, but is rarer in the eastern part of its range, while it becomes abundant in the Mississippi Valley. It causes only local damage, and few cases of destructive appearance have been recorded. In common with the differential and two-striped locusts, it often gives cause for alarm by devastating grass-lands or growing crops. The California devastating locust (Caloptenus devastator) is a Pacific species, of which fifteen local destructive visitations are recorded. The differential locust (Caloptenus differ entialis) ranges through Illinois, Missouri, Nebraska, Kansas, and Iowa, and is found in Indiana, New Mexico, and California. Though not migratory, it is capable of making considerable flights, and is sometimes locally destructive. The two-striped locust (Caloptenus bivittatus) has an extensive range, covering most of the country. It is distinguished by its two lateral stripes reaching from the head to the extremities of the wing-covers. It often becomes locally abundant enough to do much damage to crops. The pellucid locust (Camnula pellueidd) occurs in the far West and in Maine, Massachusetts, Vermont, and Connecticut. The Eastern and Western forms used to be considered two species, but the difference between them is not appreciable. The American Acridium (Schistocerca americana) is our largest locust, being more than two inches and a half long. It occurs throughout the Southern States, through Mexico into Central America, and as far north as Illinois and Indiana. It is sedentary within the bounds of the United States, and becomes only locally destructive. Farther south, it is said to possess the migratory habit.
Objects of Forest Management.—Forest management, says Prof. B. F. Fernow, in his excellent paper on What is Forestry? has two objects in view, of which the first is to produce and reproduce a certain useful material, and the second to sustain or possibly improve certain advantageous natural conditions. In the first case we treat the forest as a crop which we harvest from the soil, taking care to devote the land to repeated reproduction of crops. In the second case we add to the first conception of the forest as a crop another, namely, that of a cover to the soil, which, under certain conditions and in certain locations, bears a very important relation to other conditions of life. The favorable influence which the forest growth exerts in preventing the washing of the soil and in retarding the torrential flow of water, and also in checking the winds and thereby reducing rapid evaporation further, in facilitating subterranean drainage and influencing climatic conditions, on account of which it is desirable to preserve certain parts of the natural forest growth and extend it elsewhere—this favorable influence is due to the dense cover of foliage mainly, and to the mechanical obstruction which the trunks and litter of the forest floor offer. Any kind of tree growth would answer this purpose, and all the forest management necessary would be simply to abstain from interference and leave the ground to Nature's kindly action. This was about the idea of the first advocates of forest protection in this country. But would it be rational and would it be necessary to withdraw a large territory from human use in order to secure this beneficial influence? It would be, indeed, in many localities, if the advantage of keeping it under forest could not be secured simultaneously with the employment of the soil for useful production; but rational forest management secures the advantages both of favorable forest conditions and of the reproduction of useful material. Not only is the rational cutting of the forest not antagonistic to favorable forest conditions, but in skillful hands the latter can be improved by the judicious use of the axe. In fact, the demands of forest preservation on the mountains, and the methods of forest management for profit in such localities, are more or less harmonious; thus, the absolute clearing of the forest on steep hill-sides, which is apt to lead to desiccation and washing of the soil, is equally detrimental to a profitable forest management, necessitating, as it does, replanting under difficulties. Forest preservation, then, does not, as seems to be imagined by many, exclude proper forest utilization, but, on the contrary, these may well go hand in hand, preserving forest conditions while securing valuable material; the first requirement only modifies the manner in which the second is satisfied.
The Zebra's Stripes.—It has been shown by several authors that the stripes of the zebra are a means of protection to it in the forests, by producing light effects like those of the limbs of the bushes by which it is surrounded. One can readily see, says a correspondent of Nature, how the shadows of the branches in a tropical forest, falling upon the zebras, would so intermingle with the stripes of the animals as to add enormously to the difficulties of recognition by human eyes, and also by the eyes of their animal foes. This correspondent believes that the stripes have a still deeper meaning and value. At night, when the animal is lying down partly on its side and partly on its belly, and doubles up its legs, the horizontal stripes on them run in the same general direction with the vertical ones of the body and seem to be continuations of them; or, if it rests on its side and stretches out its limbs, the vertical, diagonal, and horizontal stripes would then be more horizontal than anything else, but pointing in different directions, and would so assimilate themselves with the crossed and varying directions of the shadows as to have the same practical effect in hiding the sleeping animal from its foes.
An Ancient Japanese Burial Custom.—Prof. Hitchcock, of the Smithsonian Institution, calling attention, in a paper on Ancient Tombs and Burial Mounds of Japan, to some small clay figures representing human beings, said it was an ancient custom in Japan to bury the retainers of a prince standing upright around his grave. The compassion of the Emperor Suisina (97-30 b. c.) was aroused by the sufferings of the persons who were thus treated when his younger brother died, and he desired to change the custom. When the empress died, the plan was proposed of substituting clay figures of men and horses for the living victims. From the publication of an edict in the year 646 forbidding the burial of living persons, and also the burial of gold, silver brocade, diaper, or any kind of variegated thing, it is inferred that the custom of living burial was kept up to some extent till the seventh century. Specimens of the figures, called tsuchi ningio, introduced to take the places of the living sacrifices, are now very rare, and this fact leads to the supposition that the figures were not buried, but were left exposed on the surface of the ground.
The Lung-fish.—The Ceratodus or lungfish of Queensland, according to Prof. Spencer's account of it in the Australasian Association, lives only in the Burnett and Mary Rivers, in Queensland, and belongs to a small group which may be regarded as intermediate between the fishes and the amphibia. The swimming bladder of ordinary fishes has been modified so that it serves as a lung. In Africa, Protopterus, a form closely allied to Ceratodus, makes for itself a cocoon of mud, in which, during the hot, dry season, it lives, and can breathe by means of its lung. The Ceratodus does not appear to do this, and probably never leaves the water. It comes continually to the surface, and passes out and takes in air, making a faint spouting noise. The author suggested that the lung was of the greatest service to the animal, not during the hot but during the wet season, when the rivers are flooded and the water is thick with sand. The Ceratodus appears to be herbivorous, and feeds largely on the seeds of gum trees which fall into the water.
Dealing with Contagions.—A report by Dr. A. Jacobi calls attention to some peculiar difficulties in dealing with the contagion of scarlet fever and diphtheria. No general hospital must admit patients suffering from either disease. Hotel-keepers are not willing to admit them; but if cases get lodgment within their houses, it is to their interest to conceal the fact. Their interest, however, does not go so far as to induce them to destroy or disinfect curtains and carpets, and purify the walls of rooms, and the contagion is perpetuated. Rooms and suites of rooms in large and expensive hotels are known in which cases of diphtheria have occurred for several years in succession, all provoked by the same germ, lodged in the same curtains and carpets. The same danger lurks in private houses, where the well members are impei'iled by the presence of the sick one, and all the surroundings are liable to be infected; and in tenement-houses, where close contact of the well with the sick can hardly be avoided. Patients should be removed from homes and hotels and isolated; but this is impossible, for the want of provision for the proper care of such cases. The only institution for these diseases in New York is the Willard Parker Hospital, which is in a remote part of the city, and has beds for only seventy patients, while twenty-five hundred persons die annually of the infections. Plans for new hospitals are proposed by the Medical Society of the City of New York, and with them stations or refuges, where the children of families in which diphtheria or scarlet fever is prevailing can be housed until the patients at home have recovered or been removed, and their residences, bedding, and furniture have been thoroughly disinfected.
Treatment of Potato Disease.—The treatment of potato disease with sulphate of copper has been found efficacious at Nantes, France. A dressing of three pounds of sulphate of copper to twenty gallons of water, or of two pounds of sulphate of copper and four pounds of lime to twenty-five gallons of water, is used. The best results are obtained by using whole potatoes, sound, of medium size, selecting those which show the finest germs, and cutting very large ones in two. Before planting they are steeped for twentyfour hours in a bath composed of six pounds each of sulphate of ammonia and nitrate of potash and twenty-five gallons of water; then allowed to stand twenty-four hours to give the sprouts time to swell—whereby the growth is quickened and the return is increased. Disease in tubers is arrested by dipping them in a bath of water and as much lime as it will take, and drying them. The diseased part seems to solidify after this treatment, and does not spread, while the good part continues sound.
Propagation of Fine Flower Seeds.—From an address by Mr. George F. Daniels, quoted in Garden and Forest from the Journal of Horticulture, we learn that the increased demand for flowers in England and America has given a corresponding impetus to seed-growing abroad, where they have the advantage of cheap labor and a climate especially adapted to the work. The secret of successful cultivation in Germany lies in the bright, dry autumn, which enables seeds to stand longer and become more thoroughly ripened. The soil is also well adapted for the purpose. Stocks are one of the most expensive crops, in the item of labor, because the finer varieties have to be grown in pots, and they require attention in watering. China asters are grown by acres, one firm devoting more than a hundred acres to them. Petunias require much attention, as each bloom has to be fertilized by hand to insure the setting of the seed. The pollen from the double blooms is very difficult to obtain, the flowers being so dense that they have often to be removed from the plant, then placed in wet sand and pulled open, so as to allow the sun and the air to ripen the pollen, which is carefully removed and placed on the finest single blooms. Calceolarias are shy seeders, and the most careful hybridization is necessary to insure a crop. Every bloom is examined, and the pollen is taken from the stamens and placed on the pistil. As the operation must be performed when the pollen is quite ripe, the flowers must be looked through nearly every day to catch each bloom as it comes to maturity. Seed is very difficult to obtain from carnations, and then only in small quantities. The commoner kinds of annuals are grown in masses. The plan of improving stocks of seed is as follows: As soon as the plants are fully in bloom they are carefully examined, and the best and truest in color or shape are marked by placing a stick next to them. When the seed is ripe they are carefully gathered by themselves, and kept for stock the following year. This is very necessary in case of some annuals, which show a great tendency to revert to the wild state; at the same time it improves the stocks from year to year.
Aluminium in Food-vessels.—Opinions still differ with regard to the value of aluminum for use in food-containing vessels. Messrs. Lübbert and Roscher asserted several months ago, in a paper on the subject, that aluminum was too readily acted upon by food-substances or other substances used in cooking, for its application in the construction of kitchen utensils to be safe. Prof. Lunge afterward instituted experiments on the subject, from which he concluded that coffee, tea, and beer had practically no action on aluminum, and the action of brandy was very slight; while that of acids and acid liquids (wine, sour milk, and fruit juices) was more pronounced, but still too slight to cause alarm. Taking the worst case, that of acetic acid, this author found a maximum attack of five milligrammes per one hundred square centimetres in six days; so that a given vessel, kept always full, would be reduced to half its original weight in fifty-five years. This, he holds, is too trifling an action to be considered. There is no danger of any injurious action upon the human body by aluminum compounds, which, moreover, are not poisonous as compounds of arsenic, mercury, lead, and copper are poisonous. Before they can act injuriously, a quantity will have to be ingested a hundred times larger than he found to be regularly entering the stomach in this way. Finally, he adds, aluminum may be employed without fear for canteens or any other vessels used to hold food, at least at ordinary temperatures. Against these conclusions is a report on the authority of the telegraph of a soldier near Nuremberg, Germany, who was taken sick after drinking cognac from his aluminum flask. On analysis of the brandy it was found to be muddy, and to contain roundish, black particles, which proved to be aluminum and iron. But in this case we had not simple corrosion of aluminum by brandy, but galvanic action of the liquor, aluminum, and iron, with resultant corrosion. Further investigation of the subject is needed.
Photography in Colors.—M. G. Lippaman announces that he has perfected a method of photographing in colors which he mentioned to the French Academy of Sciences fourteen months ago, and has exhibited very brilliant spectra which he obtained without the interposition of the colored screen. The author claims to have obtained the compound colors of natural objects as well as the natural colors of the spectrum. He exhibits a series of plates representing a window of four colors—yellow, green, blue, and red; a trophy of French and other flags; a plate of oranges with a red poppy on top; and a many-colored parrot. The window and the parrot are of dazzling brilliancy. They were photographed with the electric light in ten minutes. M. Lippaman admits that the plates require in practice too long an exposure, and that it will be necessary to make them more sensitive.
Influence of Natural Surroundings on Human Character.—Captain F. E. Younghusband makes a remark in one of his accounts of central Asiatic exploration, on the influence of the natural surroundings on the character of the people of a country. "It has been my fortune," he says, "to travel in very varied descriptions of country—in the dense, gloomy forests of Manchuria; over the bounding grassy steppes of Mongolia; across the desolate wastes of the Desert of Gobi; and among the mountain valleys of the Himalayas and the Hindu Kush. Each different type of country produced its own peculiar impression upon me, find has enabled me to appreciate perhaps more keenly than I otherwise should have done its particular influence upon the inhabitants. The forest produces a feeling of indefinable repression; one seems so hedged in and hampered about, and longs to be free of the endless succession of trunks of trees, and to be able to see clear space in front. Far preferable, in my opinion, is the desolation of the desert, which, depressing as it may be, in some way produces also a feeling of freedom; and on the open steppes an irresistible desire to roam and wander seems to come over one, which I can well understand was the motive power which caused the Mongol hordes under Genghis Khan to overrun the rest of Asia, and part even of Europe. Again, with these Mongols of the desert and the steppes a stranger is always hospitably received, and there is little of that dread of people from the outside so frequently met with among barbarous nations. The Kirghiz of the open Pamirs, too, have some of these characteristics. But directly one enters the narrow, shut-in valleys, such as are found on the southern slopes of the Hindu Kush and the Himalayas, one finds the ideas of the people shut in too. They have a dread of strangers; they desire, above all things, to be left to themselves, and unless forced by over-population to do so, or led away by the ambitions of a chief, seldom leave the particular valley to which they belong."
Ratios of Illegitimacy.—A table of statistics of illegitimacy in Europe, published by Dr. Albert Leffingwell, shows the Irish to be the most virtuous of all the peoples, the ratio of illegitimate births among them being twenty-six in every thousand. The English rate is forty-eight, and the Scotch eighty-two per thousand. Thus we may roughly say that for every child born out of wedlock in Ireland two are born in England and three in Scotland. In Europe at large, Ireland is closely followed in its place of honor by Russia, with the low rate of twenty-eight per thousand, and by Holland with the rate of thirty-two per thousand. The Italian and French rates are respectively seventy-four and eighty-two per thousand, comparable with the rate in Scotland. Among the countries that show the highest proportions of illegitimacy are Sweden, Saxony, Bavaria, and Austria, in which the rates range from one hundred to one hundred and forty per thousand. Austria is at the opposite pole from Ireland, and takes the lowest place in morality among the European nations, with a rate of one hundred and forty-six per thousand. The inquiry into the causes of these varying rates of illegitimacy raises complicated and interesting problems. The causes generally supposed to be principal factors in the matter are poverty, ignorance, and the contamination of great cities. Examining the influence of these, Dr. Leffingwell finds it very slight. In Ireland, the lowest rates are in the poorest counties. Russia, with one of the lowest rates, is one of the poorest countries; and the author affirms that "there is nowhere such uniform relation between the indigence of a people and the prevalence of illegitimacy as to justify the hypothesis that this phase of moral delinquency in any district or country can be accurately described as caused by its poverty. As little can the influence of great cities account for the prevalence of illegitimacy. Education and creed appear to have little influence. We must seek the real factors in race and heredity, legislative restraints upon marriage, social usage, and other like circumstances."
Value of the Applications of Anthropology.—In a paper on Anthropology as a Science and as a Branch of University Education, Dr. D. G. Brinton thus estimates the value of the applications of this science: "In government and law, in education and religion, men have hitherto been dealt with according to traditional beliefs or a priori theories of what they may or ought to be. When we learn through scientific research what they really are, we shall then, and then only, have a solid foundation on which to build the social, ethical, and political structures of the future. It is the appreciation of this which has given the extraordinary impetus to the study of sociology—a branch of anthropology—within the last decade. Anthropology alone furnishes the key and clew to history. This also is meeting recognition. No longer are the best histories mainly chronicles of kings and wars, but records of the development and the decline of peoples; and what constitutes 'a people,' and shapes its destiny, is the very business of ethnology to explain. So likewise in hygiene and medicine, in ethics and religion, in language and arts, in painting, architecture, sculpture, and music, the full import and often unconscious intention of human activity can only be understood, and directed in the most productive channels, by such a careful historical and physical analysis as anthropology aims to present."
Science Teaching in Preparatory Schools.—The report of the Committee of the American Society of Naturalists on Science Teaching in the Schools embraces the answers from the colleges and preparatory schools in the North Atlantic States between Maine and the District of Columbia, to a circular of questions respecting what they require of scientific instruction. Of sixty-nine colleges from which answers were received, only eighteen require science for admission to the course for the degree of Bachelor of Arts. Eleven other colleges require science for admission to the scientific course, while forty colleges offer no recognition of the place of science in the pre-collegiate course. Of twenty-one institutions catalogued as scientific schools, ten do and eleven do not require some science for admission. Of one hundred and forty-one preparatory schools, ninety-eight include science in the course preparatory for the classical course in colleges. These facts seem to indicate that the academies and high schools are in advance of the colleges in the recognition of the claims of science. The report, analyzing the courses of instruction of the schools, shows that the plea that time can not be found for scientific study in the four years of preparatory school instruction is not well founded. The greatest difficulty in securing the right kind of scientific instruction in the schools arises from the lack of properly trained teachers. This difficulty is vanishing, and the number of teachers is increasing who possess an acquaintance with science which, though limited in scope, is in considerable part sound in method. "Let it be clearly recognized that the teacher of science demanded even in the primary schools is not one who has committed to memory some verbal propositions about science, but one who has learned to observe and experiment, to compare and reason, and the conditions are already in existence which will not fail to supply that demand."
Miss North and her Animals.—Miss Marianne North, a British naturalist and traveler, whose death we noticed several months ago, exhibits in her recently published "Recollections" a happy appreciation of the individual eccentricities of animals. A favorite dog of her father's, which was implicitly trusted, when left one day in a room with a tempting pigeon pie, could not resist stealing a pigeon, but replaced the bird with the blackened sponge which Mr. North used to wipe his pens. Miss North made friends with the sacred baboons in the Indian temples, "who came and sat by her side to criticise her drawing, or who, after breaking out in the tricks of their unregenerated monkey nature, would suddenly fold their arms and relapse into pious imbecility, as if they had been disciples of Buddha, and were meditating on the Nirvana. She commemorates her first impressions of the Queensland kangaroos, when she saw fifty come hopping down hill in single file, ludicrously manœuvring as if moved by machinery, and using their big tails for balancing rods. Shortly afterward she saw a bear taking a siesta in the fork of a tree, who merely cocked his great ears and yawned when her attendants shied stones at him. He knew he was out of harm's way. He took his constitutional only at night, and was not going to alter his habits to please anybody. She tells a capital story of a cockatoo, brought up in a zoölogical garden, and taught to say: 'Walk in, ladies and gentlemen; don't all come at once one at a time.' The bird escaped, and was found with a troop of wild cockatoos attacking it. It was lying on its back, fighting beak and claw, and screaming out: 'Come on, ladies and gentlemen, come on; not all at once, one at a time.' She heard of a South African baboon, who, having taken to brigandage, had assailed a musician returning from a dance, and captured his accordeon. Examining his prize, there was a dismal discord, followed by a hideous howl, and the robber vanished in a panic, leaving the booty behind. She encumbered herself with a family of opossum mice, and this cost her endless trouble and anxiety." But these mice proved extremely serviceable in her journey across the North American continent, for they excited such intense interest with railway guards, hotel-keepers, etc., that they always insured their mistress civility or a cordial reception.
Wild Plants as Fungus-nurseries.—Prof. B. D. Halsted shows, in a paper on fungi common to wild and cultivated plants, that in many cases diseases are transmitted by spores from one genus or family as well as from one species to another. A bacterium that affects the tomato and potato causes a disastrous form of blight in melons, cucumbers, and squashes. The apple rust that yellows the foliage of the orchard in July is identical with the gynosporangium that produces the galls, swelling out to large size in rainy weather, on cedar trees, and the spores are transmitted in alternation from one tree to the other. It is thus shown by many examples that the evil influences of plant funguses may act at long range. The lesson may be learned from the experiments that "if so much of the smut, rust, mildew, mold, rot, and blight of our cultivated plants is propagated by the wild plants hard by, it may be wise for every crop-grower to pay attention to what is thriving outside of his garden wall."
Skill of Prehistoric Lapidaries.—The most superficial examination of any fairly large collection of stone implements, says Mr. Joseph D. McGuire, in a paper on the materials, apparatus, and processes of the aboriginal lapidary, is calculated to convince the observer that man in his lowest stage of development was well acquainted with the methods of fracture of various stones, and also that he was a most skillful workman. The articles found in burial-places, in caves, and shell-heaps, as well as surface finds, furnish conclusive evidence that man often carried material many hundreds of miles for the purpose of fashioning, at his leisure, objects of personal adornment or domestic utility as well as weapons. The evidence of progress in the manufacture of tools made by man is easy to find: "From the splinter of bone or piece of stone used in the hand to the diamond drill of to-day is an immense advance, but it can be traced, step by step, without a break. The author has himself experimented on the manufacture of stone implements, using tools similar to those of the North American Indians, and beginning with the raw material. The principal work done was the pecking of stone with the stone hammer, and the carving, polishing, rubbing, and boring of stone with the rudest appliances. The result of the experiments goes far to prove that the time required for the manufacture of stone implements by primitive man was very short." If the time occupied by the writer was short, it is fair to conclude that a skillful workman, using the materials which long experience had taught him were the best for his purpose, would accomplish the task in much shorter time. The author, in his paper, records his experiments in pecking nephrite, kersantite, catlinite, obsidian, and basalt, with different hammering material, in drilling and boring, and in hammering copper, the results of which all went to confirm the view he has expressed.
Extermination of Species.—Some of the more obvious causes of the extermination of animals now going on, says Mr. Frederic A. Lucas, in his paper on that subject in the United States National Museum, are to be found in the systematic killing of animals for their various products, the destruction caused by domesticated animals introduced into new countries, and the bringing of wild land under cultivation. These causes most directly affect the larger animals, while smaller creatures are influenced by slighter ones. The erection of telegraph wires has proved destructive to birds, while other birds meet their fate by dashing against the electric lights. The extinction of the rhytina and the great auk, the almost complete extirpation of the bison, and the reduced numbers of the walrus, are good examples of destruction wrought directly by the hand of man; and, besides, there are the still more numerous instances of the very perceptible decrease of animals once abundant. Species used for food, or otherwise of economic value, suffer most; fashion affects some, some are necessarily destroyed for the protection of man and his domesticated animals, and others are killed merely for sport. The passenger pigeons, formerly visiting us by millions, are now unknown in places where they once abounded. Halibut, lobsters, and oysters are getting scarce, and the Atlantic salmon and shad are practically kept from extermination by the efforts of fish commissions. One reason for this growing depletion of animals is found in the fallacy that, because some animals exist in large numbers, the supply is unlimited and the species needs no protection, which is indulged in till the species is on the verge of extermination. Usually, too, those most directly interested in the preservation of game are the bitterest opponents of protective measures, especially if the change will produce even temporary inconvenience. Although regret at the impending or actual extermination of a species is often purely a matter of sentiment, there is no lack of instances where the strictest utilitarian is quite as much interested as the naturalist in preserving a species from destruction. The pity of it is that in so many cases a small amount of protection would not only preserve for the naturalist the animals he wishes to study, but furnish the practical man with an additional source of wealth.
Concerning Overwork.—In treating the question whether laborious occupations in themselves may lead to premature strain of the body or mind, and so to degeneration or disease, Dr. P. H. Pye-Smith thinks we "must distinguish." Aneurism, emphysema, and some forms of cardiac hypertrophy may be the result of overstrained and too violent and prolonged exertion, from mechanical stretching of the great arteries by movements of the arms, from high blood-pressure, excessive calls on the heart, and over-long suspension of respiration, as in muscular efforts with a closed glottis. "We see similar results in horses which are put to too hard work at too early an age, and there is no reason to doubt the operation of such causes of disease in man. But their operation is limited to the production of certain definite lesions, and there is no evidence that harm is done, disease brought on, or life shortened by what is commonly known as work, whether mental, physical, or a combination of the two. The vanity of human nature is tickled by ascribing its disorders to such respectable antecedents as industry, energy, and intellectual activity. We must all have felt this when the results of habitual idleness or gluttony are ascribed by a patient or his wife to an overtaxed brain or too strenuous devotion to business especially in the public service. There is no fear of any one of us" (members of the Royal College of Physicians) "using our brains too much for our health, nor do I believe that mental labor or honest work of any kind interferes with health or shortens life a day. Even if it did, who would not rather be worn in use than rust in idleness? Who would not choose a short-spanned life, filled full of action and of thought, of sorrow and of joy, of effort and of endurance, of enjoyment of living one's self and helpful service to others, rather than to wear out a tedious existence of monotonous ease?"
Agriculture in Egypt.—The land of Egypt was irrigated in ancient times by turning the red water from the Nile at high flood into the basins into which the country was divided by the construction of earth-banks at convenient distances. The water was allowed to stand at a depth of three feet or more for forty or sixty days, till the earth had become saturated and the weeds had been killed, and the fertilizing layer of finely divided red mud had been deposited on the soil. The water being drawn off into the receding river, the seed was sown upon the soft mud. Sometimes the ground was left till it was dry enough to be plowed, and was then planted. In either case sufficient moisture for the supply of the crop was retained. This system of irrigation has been supplanted for the most part in Lower Egypt by the canal system introduced by Mehemet Ali, but is still in use in Upper Egypt. The difference in the power of the two systems to maintain the fertility of the soil may be estimated from the fact that a good crop of wheat grown under the basin system of Upper Egypt yields about twenty-seven bushels per acre; while, unless specially manured, the yield runs down under canal irrigation to about eighteen bushels and a half. In the latter instance, the greater number of crops taken, and the reduced amount of Nile mud deposited, make artificial manures necessary. A combination of the two systems gives the best results. A wonderful store of natural manure, called sabakh has for a number of years been drawn upon by cultivators in the shape of refuse earth from the mounds of ancient villages, and from the floors and surroundings of the mud huts of the present generation. The water of the Nile holds in its volume an unusually large percentage of air; and it is probably due to this circumstance that it is so healthful and palatable even at its reddest. The crop seasons are divided into three different productive periods: the autumn, or nili—August till the end of November; the period of flood, in which maize, millet, sesame, and a few minor crops are grown; the summer, or sefi—April till July; the warm-weather period, in which tropical and semi-tropical crops—rice, sugar, and cotton—are produced; and the winter, or shitawi—December to March, or cold-weather period—when the European crops, grown in a temperate climate, come to maturity.
Spring Two Hundred Tears ago and now.—Has change of climate within historical times, Dr. P. H. Pye-Smith asks, brought about change of diseases? "I think," he says, "we may assert that, with a few important exceptions, such as the draining which has led to the general disappearance of malaria, and the improved habitations of the poor, which have made plague unknown and typhus rare, no such changes have taken place; and in particular that there is no foundation for the opinion that in former time the English spring was milder than at present. 'The uncertain glory of an April day' was as uncertain at the close of the sixteenth as at the close of the nineteenth century. In the seventeenth century the great Earl of Verulam met his death from standing in the snow on Highgate Hill on Easter Monday, and Evelyn remarks, under date of March 27, 1681, 'An extraordinary sharp spring, not a leaf yet on the trees.' In the eighteenth century Horace Walpole writes that 'the spring has set in with its usual severity'; and the contrast between poetical description of the 'ethereal mildness of spring' and its actual inclemency has become a commonplace of satire."
Typhoid Fever and Sewage in Drinking-water.—Outbreaks of typhoid fever occurred in several of the half-dozen cities and towns situated near the junction of the Hudson and Mohawk Rivers during the winter of 1890-91, and, while their cause can not be fixed with certainty, Prof. William P. Mason, of the Rensselaer Polytechnic Institute, holds that there is good reason to attribute them to a contaminated water-supply. In a paper read to the Franklin Institute he states that every one of these places drains into the Hudson River or its tributary, the Mohawk. There were epidemics of tvphoid fever in Cohoes, West Troy, and Albany, which take their supplies of water from one or the other of these rivers; but in Waterford and Lansingburg, which take water from the Hudson above this group of towns; in Troy, which uses in part a similar supply and depends partly on the lakes back in the hills; also on Green Island, opposite Troy, which obtains sand-filtered river-water from wells, there was little or no fever besides imported cases. Ice-cutters at Van Wie's Point, four miles below Albany, who used the river-water for drinking, also had the fever break out among them. It is true that typhoid germs were not found in the water, but the facts above cited are certainly worthy of careful consideration.
Sulphuring Dried Fruit.—The dainty whiteness which commercial dried fruits have taken on within a few years is due to an unwholesome bleaching by means of the fumes of burning sulphur, which is practiced in the drying factories. Fruit-driers say that sulphuring makes the fruit dry quicker, keep better, and sell better. But these advantages do not benefit the consumer, who suffers the disadvantages, which are loss of flavor, impossibility of distinguishing unripe and poor fruit from good, and the presence of sulphide of zinc in fruit that is dried on trays having a zinc surface. This matter is thoroughly ventilated in the Transactions of the American Public Health Association by Dr. Joel W. Smith, who says further that the contamination with sulphide of zinc was the reason why American evaporated apples were excluded from Germany. He also quotes from a paper read by J. L. Mosher at a fruitgrowers' convention in California the statement that "if fruit be picked before ripe, and over-sulphured to produce whiteness, it is devoid of its true rich taste and flavor, and only requires polishing to make buttons."
Physiology of Over-exertion.—Pertinently to the death of a young Englishman, twenty-two years old, from syncope brought about by cold and over-exertion attendant upon a bicycle-ride of forty miles, the Lancet remarks: "It appears that this young man was a practiced bicycle-rider, and to such forty miles could hardly be considered an excessive run in a day; but, besides distance, many things have also to be considered by the judicious rider—for instance, the nature of the roads, the weather, and perhaps, above all, the pace. We know that the new machines are capable of attaining a speed never thought of a few years ago. A high speed through such cold air as prevailed on Good Friday must often be very dangerous, as likely to cause pulmonary congestion, to overcome which the heart will work at a high degree of tension, and, like any other muscle, it is likely to become paralyzed from overwork; and herein lies the danger from swift and hard riding. It would be well if our young men would remember the advice that an eminent English physiologist gave to a young man some years ago, 'Observe your strength, and keep within it.'"
Retrieved from "https://en.wikisource.org/w/index.php?title=Popular_Science_Monthly/Volume_41/August_1892/Popular_Miscellany&oldid=8847216"


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Twenty years of the Fightinghawk
By Esteban G Brea 15th February 2018
Argentina took delivery of its first Fightinghawks 20 years ago in December. Esteban G Brea reviews the fighterbomber's service with the Argentine Air Force, which has included its fair share of setbacks.
OA/A-4AR in FAA service
Two generations of 'Hawks served together in the Argentine Air Force until 1999. Here an A-4B veteran of the Malvinas/ Falklands conflict is seen alongside its Fightinghawk successor on the tarmac of the V Brigada Aérea's Villa Reynolds home
Fightinghawks are regularly involved in air policing tasks. One of the most recent was the Operativo Fronteras mission last year, for which the radio frequency was applied to the drop tanks in order to aid communications with aircraft once they were intercepted.
All photos Esteban G Brea
In the wake of the 1982 Malvinas/ Falklands conflict, the Fuerza Aérea Argentina (FAA, Argentine Air Force) needed to replace its losses – which included no fewer than 19 A-4 Skyhawks – a task made more difficult by an international arms embargo. Buenos Aires managed to acquire Mirage IIICJ and Mirage 5P fighters from Israel and Peru respectively, while IA-58 Pucará attrition was made good by new units from the production line of the state-owned Fábrica Militar de Aviones (FMA).
Originally published in AirForces Monthly Magazine
Find out more about AirForces Monthly here.
Pucará over the Pampas
LAST PUSH FOR THE PUCARÁ

redpajama_set_name: RedPajamaCommonCrawl


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Dysprosium(III)-fluorid ist eine chemische Verbindung des Seltenerd-Metalls Dysprosium aus der Gruppe der Fluoride.

Gewinnung und Darstellung
Dysprosium(III)-fluorid kann durch Reaktion von Dysprosium(III)-oxid mit Fluorwasserstoff gewonnen werden.

Eigenschaften
Dysprosium(III)-fluorid ist ein weißer geruchloser Feststoff, der unlöslich in Wasser ist. Er besitzt eine orthorhombische Kristallstruktur mit der .

Einzelnachweise

Dysprosiumverbindung
Fluorid

redpajama_set_name: RedPajamaWikipedia


The exciting layered look comprising textured and silky fabric and the sophisticated contrast stitching give this top a particularly fashionable note.
Lovely top. Good fit. Like the slightly sporty look to it with the white stitching. The size recommended by Esprit said I should purchase a size s but a size xs fit well enough. However I had to order both sizes to be sure.
Ordered multiple sizes xs and s. Kept the xs returning the s.


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Home > Take Action > Get Involved > COPD Awareness Month
Each November, the COPD Foundation and its community increase the focus on building awareness for chronic obstructive pulmonary disease (COPD). This year, the Foundation's COPD Awareness theme is Lace-Up for Lungs: Let's Outpace COPD. We're committed to innovative approaches to preventing COPD and encouraging early diagnosis while improving lives and advocating for all affected.
COPD Awareness Month Toolkit >
Donate to Lace-Up for Lungs >
Did you know that 16 million U.S. adults have COPD1, and millions more are undiagnosed and unaware that they have the disease. COPD kills more than 150,000 people each year in the United States2 and more than 3.2 million people worldwide.3
Despite the high number of deaths, COPD is ranked 176th in research funding in the U.S.4
We welcome our community and those interested in learning more about COPD and its impact to go the distance and join us for Lace-Up for Lungs. Together, we can bring greater visibility to the disease and educate, engage, and empower the public to recognize COPD symptoms and seek diagnosis and treatment.
Explore COPD Awareness Month Educational Resources:
What is COPD? What do You Need to Know About COPD Symptoms?
COPD, or chronic obstructive pulmonary disease, is an umbrella term used to describe chronic lung diseases, encompassing emphysema, and chronic bronchitis. The disease is characterized by increasing breathlessness.
Unfortunately, the disease can progress for years if it is undiagnosed. It's important to talk to a health care provider as soon as you experience symptoms, including increased shortness of breath, frequent coughing, wheezing, chest tightness, and unusual tiredness.
While many are not diagnosed with COPD until age 40 or later, early signs of COPD can be found in adults as young as 20 years old.
Early diagnosis is critical to help reduce your lung damage and to help with your quality of life as you manage COPD. Your health care provider can order a Spirometry test and help you establish a COPD care and management plan.
Currently, COPD is an incurable disease; however, it is treatable, and a person diagnosed with COPD who receives the correct diagnosis and treatment can breathe better, thrive, and enjoy their quality of life.
Do you have questions about symptoms you may be having? Visit our Risk Screener and find out more, then speak with your health care provider.
Learn More About the Basics of COPD
Are you new to COPD? The Foundation developed helpful tools for people recently diagnosed with COPD. Download this free guide to understand The Basics of COPD. This guide covers essential topics, including how COPD is diagnosed, treatment options, managing COPD symptoms, flare-ups, tips for living well with a lung condition, and coping with COPD.
Download your free personal-use copy of The Basics of COPD.
Health Podcast Series: The COPD Podcast
The COPD Podcast is a health podcast series dedicated to raising awareness for chronic obstructive pulmonary disease (COPD) and helping guide those affected by the condition so they can live their best lives. Podcasts are brought to you by the COPD Foundation and Health Unmuted.
Whether you are a person with COPD, a caregiver, or a clinician, we trust you'll find The COPD Podcast to be a valuable companion along your journey! Listen to Podcast Episodes here.
Anyone Can Get COPD
Did you know that anyone can get COPD? Download this flyer and learn about the ways that COPD can impact you, your family, or your friends.
COPD and You: Early Diagnosis
Download this helpful flyer to learn how you can look for, listen to, and act on any COPD symptoms you or your loved ones might be experiencing. Early diagnosis can make a difference.
Learn More about Bronchiectasis and NTM Lung Disease
Discover more about Bronchiectasis and NTM Lung Disease to help you understand what they have in common with COPD, how they're diagnosed and treated, and other topics. See the articles and information here:
What is Bronchiectasis, and how can it overlap with COPD?
Bronchiectasis Frequently Asked Questions (FAQs)
NTM Lung Disease: How it is Diagnosed and What you Need to Know
Hear from a bronchiectasis patient in this video, Living Well with Bronchiectasis
Understand COPD: FAQs
Did you know that quitting smoking is one of the best things you can do that is proven to slow COPD progression? And did you know that a person who has never smoked can develop COPD?
Learn more about COPD by visiting our COPD Frequently Asked Questions.
If you're considering quitting smoking, you'll enjoy this blog:
Teaching with a Twist - Quitting Smoking: Why should you?
Exercise and COPD: It Can Be Good for You to Lace-Up for Lungs! Join us for COPD Awareness Month as we Lace-Up for Lungs: Let's Outpace COPD
Exercise Endurance: Use It or Lose It!
You know that old saying, "If you don't use it, you'll lose it"? Exercise is one of those things that you must do frequently and routinely, or you will lose endurance and stamina. Check out these resources:
Exercise For a Person with COPD
Staying Active at Home/Upper Body Exercises
Staying Active at Home/Lower Body Exercises
#LaceUpforLungs Challenge
I'm ready to Lace-Up for Lungs
Learn how you can join the social challenge and spread awareness for COPD, bronchiectasis, and NTM. You can dress in your favorite bright orange gear (laces, hat, shirt, etc.), hold up your free, downloadable sign, and tell us whom you lace-up for. Is it Mom? Dad? Your neighbor? Or maybe you lace-up for yourself?
Ready to learn more about Lace-Up for Lungs? Great, let's get moving together and spread awareness for COPD as we Lace-Up for Lungs: Let's Outpace COPD.
Watch this video from our own Mike Hess as he asks you to join us and Lace-Up for Lungs.
Learn about Lace-Up for Lungs >
COPDSOS: 30 Million Americans Have COPD; Half Don't Yet Know It
COPD SOS is a public service campaign developed in partnership with the Dorney-Koppel Foundation, the COPD Foundation, and others focused on identifying the "missing millions" who have COPD but don't yet know it. Since her diagnosis in 2001, Grace Anne Dorney Koppel has been a voice for those with COPD. She and her husband, broadcast journalist Ted Koppel, created the Dorney-Koppel Foundation to bring attention to this devastating disease and lead the charge in the fight against it.
Learn about COPDSOS >
2022 COPD Awareness Month Events
Nov. 1, 4 p.m. EDT: Webinar: International Survey Highlights Patient Opinions About Tobacco Industry Ownership of Pharmaceutical Companies, brought to you by the US COPD Coalition and the COPD Foundation. Sign up: https://bit.ly/intl-patients-survey
Nov. 11, All Day: Join us and Lace-Up for Lungs in Support of Veterans. Please take a picture or video as you Lace-Up for Lungs and share it on social media to recognize veterans with COPD and other lung illnesses. #LaceUpforLungs #VeteransDay
Nov. 11, 1 p.m. EST: Veterans' Day Harmonicas for Health Play-Along. Register here: https://bit.ly/VetsDay-H4H
Nov. 16, 2022, 8 a.m. - 6 p.m. EST: The COPD Foundation hosts a booth in the exhibit hall at GOLD International COPD Conference, Sheraton Philadelphia, Downtown. Conference information: https://bit.ly/GOLDCOPD-conference
Tuesday, Nov. 29, All Day: Giving Tuesday. Support Lace-Up for Lungs: Let's Outpace COPD by pledging your support for the Foundation. You can give here: https://www.copdfoundation.org/Take-Action/Donate/Lace-Up-for-Lungs-Donation.aspx
We Are Grateful for the Following Supporters of COPD Awareness Month:
https://www.who.int/news-room/fact-sheets/detail/chronic-obstructive-pulmonary-disease-(copd)
https://www.cdc.gov/dotw/copd/index.html#:~:text=Key%20Facts,1%20death%20every%204%20minutes!
https://www.who.int/news-room/fact-sheets/detail/chronic-obstructive-pulmonary-disease-(copd)#:~:text=Key%20facts,%2Dincome%20countries%20(LMIC)
https://report.nih.gov/funding/categorical-spending#/
This page was reviewed on November 14, 2022 by the COPD Foundation Content Review and Evaluation Committee


Fact is the car needs to be sold in a hurry.
puts on a new white blouse, new heels.
he says. I know where to start, she says.
Things are going to be different, he says.
he makes a large drink, turns the TV on.
Nine. She's been gone nearly five hours.
At ten, he hears the telephone ringing.
I wanted to call, she says. Where are you?
go now, she says, . Wait, he yells.
and he hears her fall on the bed and groan.
across the front of the car, gets back in.
Wait! Leo calls and starts down the steps.
says and watches for sudden movement.
says. Between friends, are these actual miles?
What I love most about this story is the different tensions at play. Toni and Leo corkscrewed themselves into a situation where they've gotta hawk their car for cash before they have to file for bankruptcy, but the best way to sell the car, or so Leo and Toni think, is to have Toni go out and sell it. This increases the tension because we have to sit with Leo as he's waiting for his wife to return from this sale. After she calls and quickly hangs up and then he can't get her back on the phone, I'm fraught with panic just as Leo is.
The situation's already desperate, but this uncertainty, which never really gets answered, about Toni's fidelity amps up the stakes of the story. The initial question of whether or not she made the sale takes a back seat to our question of what she's doing out so late with strange men who have fat wallets. By the end of the story, we can't do much more than assume, which is exactly the position Leo's in. But the way Toni comes home drunk and upset, the guy returning her makeup bag…it seems to suggest some kind of infidelity.
Carver's story gets its title from the question the guy asks Leo as he's dropping off the makeup bag the following morning. It's just more salt for the wound. Not only did this guy probably sleep with Leo's wife, but his question just highlights how good a deal he got on their car. By the end, when Leo walks back inside, I'm half expecting him to burst into a fit of unchecked rage, but the final gesture, the image of him tracing the stretch marks in her legs, it's so goddamn sweet and unexpected and perfect. The road simile ties in not just the car they just sold, but their past, the roads they've traveled together. The story sings on both concrete and symbolic levels. Just so so good.


text:
C3 pastor Josh Kelsey says that successful church planting is all about creating momentum
C3 Church knows the power of dinner parties
Founder of C3 in Brooklyn, New York, Josh Kelsey says that success is all about building momentum around the dinner table
Teagan Russell | April 12th, 2017 06:05 PM	| Add a Comment
Five thousand people gathered at the newly built International Convention Centre in Sydney's Darling Harbour this week for C3's annual Presence Conference.
Now in it's 13th year, Presence is a chance for the C3 family of churches – which now numbers over 450 churches in a staggering 64 countries – to gather together and encourage one another.
Founded by Phil and Chris Pringle in Sydney in 1980, C3 is a global movement of Pentecostal Churches. If overseas numbers are taken into account, C3 is one of Australia's fastest-growing churches, and is on track to meet its vision of 1000 local churches planted by the year 2020.
Guest speakers at Presence this year included Steven Furtick (founder and lead pastor of Elevation Church in Charlotte, North Carolina, and a New York Times bestselling author); Martin Smith (Grammy Award winning songwriter, producer and worship leader) and Lisa Bevere (bestselling author, speaker and co-founder of Messenger International).
"Good pastoring leads people to feed themselves."- Josh Kelsey
This year, Presence launched 15 masterclasses covering a wide range of topics for people from all walks of life – everything from becoming a better communicator to healthy family life, money matters, and women in leadership.
At Tuesday morning's masterclass on church planting, founder of C3 Church in Brooklyn, New York, Josh Kelsey described his vision for what he called a dinner party church.
"Our vision will always be to be a dinner party church – meaning, our vision is to have a dinner party on every block. Our vision is not to have a big service. I believe big services are very easy when you have a great community. Sundays should look after themselves if we have momentum around the table."
"We need to count so that we know where the people are." – Josh Kelsey
Kelsey and his wife Georgie planted C3 Brooklyn in 2013. Every Wednesday night, their church runs "Dinner Parties" across New York City. Each dinner party is run by a team of four leaders so that if a particular leader can't attend, the dinner party will still go ahead, and this helps build weekly momentum.
Teaching from the parable of the lost sheep in Luke 15, Kelsey shared principles for building a church with momentum.
"Good pastoring leads people to feed themselves," said Kelsey.
"In the parable, the shepherd leaves his 99 sheep to go after one lost sheep. But if pastors and leaders do not do a good job of looking after the 99, they can't leave them to go after the lost one," Kelsey said.
He added that just as the shepherd knew the sheep was lost because he had counted his sheep, his leaders always count and report the attendance of the weekly dinner parties.
"In the Western world we have an avoidance of counting numbers, but we need to count so that we know where the people are," Kelsey said.
And when the shepherd found the "one", said Kelsey, he rejoiced. So at the Dinner Parties it is important for leaders to create a party atmosphere to celebrate each lost one being found, he said.
Kelsey went on to talk about the inevitable modern day persecution which will come, and said that the church has to have a model that won't be destroyed by persecution.
"Only a big meeting model will fall apart if we don't have strong family and community that can go underground and still grow at the same time."
He said that he's not against big services, because we have to have them, "but we have to have both."
C3 hopes to plant another 550 churches globally by the year 2020.
What all Christians need to know about Pentecostalism and Scott Morrison
31 May 2019 3:01PM
The latest in a series of articles in secular media seeking to explain Prime Minister…
Tara Conradt
Never too old to be born again
28 Dec 2019 12:20AM
Friends Ray Turner, 82, and Chris Lawes, 75, were very proud of each other when…
Ten reasons why - a response to Mark Powell
Why Christians should engage in Welcome to Country or Acknowledgement of Country
Daryl McCullough
Bobbie Houston on retirement, facing criticism and the word 'megachurch'
23 May 2019 12:00PM
An in-depth, personal conversation with the Hillsong leader
12 ways to be a true evangelical
Graham Hill on being an "evangelical"
Can 'Christian' political parties survive?
Christian Democrats need a massive overhaul says former state director
It's not 'persecution' but these Christians got a raw deal
A note from Eternity: Here's one simple test is simple for whether a Religious Discrimination Act…
John Steenhof
Country kids on board for major youth convention
Distance won't be an obstacle to show kids from rural areas that they're part of something bigger.
Rebecca Abbott
Eternity marks the roll: the kids at the Climate Strike
Many passionate Christian teens raised their banners among the hundreds of thousands who rallied at…
'Don't be comfortable but share the comfort of Christ': Ann Voskamp
4 Mar 2020 11:03AM
The call to Christian hospitality
The unknown missionary force targeting a suburb near you
13 Mar 2020 11:01AM
Cross-cultural mission in our own backyard


Sant Vincenç de Castellet is a municipality in the comarca o the Bages in Catalonie, Spain. It is situatit near the confluence o the Llobregat river an the Cardener river. The railwey station serves baith the FGC line R5 atween Barcelona an Manresa an the RENFE line atween Barcelona an Zaragoza. The C-1411 road links the municipality wi Martorell an Manresa.
The ruins o baith Castellet castle an o a Roman tomb (third century, kent locally as la Torre del Breny) are visible.


The latest installment of our free audio podcast features short fiction from Lane Ashfeldt. You can either right-click here to download a copy of the author reading her piece, "The Bells at Christchurch", or you can subscribe using and get automatic updates with your RSS reader or through iTunes.
This entry was posted in fiction, Green Press Writers, podcast and tagged Lane Ashfeldt by greenpressadmin. Bookmark the permalink.
That's a bloody good radio production and reading of a tasty story.


text:
package org.discotools.gwt.leaflet.client.marker.label;

import org.discotools.gwt.leaflet.client.Options;

/**
 * Options for Label
 * @author David Ignjic
 *
 */
public class LabelOptions extends Options {

    /**
     * the css class to add to the label element
     * @param className
     */
    public LabelOptions setClassName(String className) {
        setProperty("className", className);
        return this;
    }

    /**
     * doesn't attach event handler for showing/hiding the label on mouseover/out.
     * @param noHide
     */
    public LabelOptions setNoHide(boolean noHide) {
        setProperty("noHide", noHide);
        return this;
    }

    /**
     * Remove nices border from label
     * @param withoutDefaultStyle
     */
    public LabelOptions setWithoutDefaultStyle(boolean withoutDefaultStyle) {
        setProperty("withoutDefaultStyle", withoutDefaultStyle);
        return this;
    }

    /**
     *
     * @param paneName set panename (like "popupPane","markerPane","overlayPane") where label will be added (z-index)
     */
    public LabelOptions setPane(String paneName) {
        setProperty("pane", paneName);
        return this;
    }
}

redpajama_set_name: RedPajamaGithub


Although the popularity of under-gravel filters is not what it once was, high-quality models are still viable options for aquarium hobbyists. Under-gravel filters are usually affordable, and the differences between those produced by premium manufacturers are subtle. Nevertheless, three high-quality units share several key features and will help keep your tank's water clean.
In essence, under-gravel filters work by turning the gravel bed into biological and mechanical filter media. Under-gravel filters have three key components. One or more plastic, perforated plates sit below the gravel in the tank and creates a layer of water underneath the gravel. A tube sits vertically in the tank, and connects to either an air stone or a water pump. The stone or pump causes water to flow up through the tube. In doing so, the tube draws water from the space below the gravel, which in turn pulls water through the gravel bed. This movement pulls particulate matter deeper into the gravel, and provides a high amount of surface area to host beneficial bacteria.
Historically, under-gravel filters were the only type of filters that were effective and readily available. Many hobbyists who began keeping fish at this time, still rely on under-gravel filters to keep their aquariums clean, even though other options are available. Conversely, new hobbyists often select a canister that hangs on the back of the tank or wet-dry filter to maintain their tank filtration. While under-gravel filters require less maintenance than most other filters, hobbyists must clean the gravel periodically to ensure adequate water flow, and conduct weekly, partial water changes.
There is no shortage of under-gravel filter manufacturers, and many budget models exist. While you may save a few dollars by selecting such a model, you will get better value from a premium under-gravel filter. Some hobbyists prefer air-driven units, while others prefer systems powered by water pumps. Each type has pros and cons: Air-driven systems often work with an optional filter cartridge, while water-driven systems usually produce higher flow rates. Understand that under-gravel filters are not appropriate for all tanks. You should opt for a different type of filtration if you have a reef tank, a heavily planted tank or one with slopping gravel.
Three under-gravel filters are effective and popular among hobbyists; not surprisingly, they are all similar. Lee's Premium Undergravel Filter is an air-powered unit that can accommodate optional chemical filtration cartridges. Additionally, the filter's plates are made of crack-resistant plastic, and the design includes excluders to prevent fish from accessing the apparatus. The Penn Plax Undertow and Penn Plax ClearFree Premium under-gravel filters are similar in basic design and features. The primary differences between the three products involve subtle details of the filter plates.


A proposed mandate requiring electronic logging devices in Canadian commercial vehicles would unjustly burden small-business operators and provide no safety benefit to Canada's motorists, according to comments filed on behalf of the Owner-Operator Independent Drivers Association.
The comment period for the proposed mandate ended Sept. 16. Johanne Couture, an OOIDA senior member from Brockville, Ont., filed comments on behalf of the Association.
"If ELDs do indeed improve efficiency and effectiveness, then the market will drive the adoption of these tools for all carriers, large and small," Couture wrote. "All motor carriers should be allowed to manage their operations in the manner which is most efficient for them, whether that be with an ELD or not."
An owner-operator with 23 years of experience transporting freight throughout the U.S. and Canada, and more than 3 million safe miles, Couture also serves as a member of the Canadian Council of Motor Transportation Administrators' compliance and review board.
The comments state there is no evidentiary basis to support claims that ELDs improve safety. Couture also cited the results of Canada's Roadcheck 2016, which found that the average out-of-service rate for Canadian drivers was less than 2 percent, of the more than 8,000 drivers inspected during the three-day enforcement campaign.
Earlier this summer, a study by the Canadian government's top transportation agency claimed the nation's proposal to mandate the use of electronic logging devices by federally regulated motor carriers and commercial drivers will help reduce crashes. But research by the OOIDA Foundation suggests ELDs would prevent only two crashes per year on average.
On Aug. 3, Transport Canada announced it would be proposing an amendment on the country's hours-of-service regulations, mandating the use of ELDs for all federally regulated bus and truck carriers and drivers who are required to maintain a logbook. As part of that release, the agency also announced it was seeking preliminary comments before the issuance of a proposed rule to be published in the Canada Gazette Part I, likely in early 2017. While an exact phase-in period and compliance dates have not been established, the cost-benefit analysis states that Transport Canada would try to align those dates with the U.S. ELD mandate of December 2017 "to the extent possible."
OOIDA has filed a lawsuit seeking to overturn the U.S. mandate. Oral arguments took place Tuesday, Sept. 13. The Association is seeking a petition for review of the rule and procedures the Federal Motor Carrier Safety Administration followed in arriving at the rule. A successful review can result in all or part of a rule being overturned.
"None of these costs are necessary for a carrier which does not require an ELD," Couture wrote. "A properly trained driver can record their duty status and keep track of their total on-duty hours without an ELD."


text:
Cryptocurrencies Aren't Big Enough to Pose Financial Stability Risk – Regulation
July 18, 2021 Latest
Bank of England Deputy Governor Jon Cunliffe believes that cryptocurrencies are not big enough to pose financial stability risk. "They're not of the size that they would cause financial stability risk, and they're not connected deeply into the standing financial system," said the deputy governor.
Crypto Poses No Financial Stability Risk, Says Deputy Governor of Bank of England
Jon Cunliffe, the deputy governor of the Bank of England, talked about cryptocurrency and whether it poses financial stability risk in an interview with CNBC Wednesday. He said:
The speculative boom in crypto is very noticeable but I don't think it's crossed the boundary into financial stability risk.
The Bank of England's deputy governor explained that crypto speculation was mainly limited to retail investors currently. He reiterated the British central bank's position that people investing in cryptocurrency should be prepared to lose all their money, the viewpoint expressed on several occasions by Andrew Bailey, the governor of the Bank of England.
Cunliffe described:
There are issues of investor protection here. These are highly speculative assets. But they're not of the size that they would cause financial stability risk, and they're not connected deeply into the standing financial system.
He noted: "Were we to start to see those links develop, were we to start to see it move out of retail more into wholesale and see the financial sector more exposed, then I think you might start to think about risk in that sense."
Cunliffe noted that speculative crypto assets, like bitcoin, should be distinguished from stablecoins, emphasizing that stablecoins should be regulated. The deputy governor opined: "I think the international community needs to at least be developing standards to actually be able to distinguish but also to have regulatory standards for that sort of product."
The governor of the Bank of England previously called cryptocurrencies dangerous, predicting that they won't last. He said in June, "There will inevitably be elements of tough love" in crypto regulation.
In May, Bailey said cryptocurrencies "have no intrinsic value," but noted that it "doesn't mean to say people don't put value on them, because they can have extrinsic value." The president of the European Central Bank (ECB), Christine Lagarde, agreed with him.
What do you think about the comments by the deputy governor of the Bank of England? Let us know in the comments section below.
'Doctor Bitcoin' Pleads Guilty to Running Illegal Crypto Exchange in US, Faces 5 Years in Prison
A Texas man, who calls himself "Doctor Bitcoin," has pleaded guilty to running an illegal cryptocurrency exchange business, …
Bank of Tanzania Hints at Possible Crypto Ban Reversal as Spokesman Confirms Bank Is 'Working on the Directives Given' – Emerging Markets
In a hint that Tanzania might soon reverse its 2019 crypto ban, an unnamed spokesperson of the Bank …
Ukraine Officials Fail to Account for Millions in Declared Crypto Assets –
Personal asset declarations filed by politicians and government officials in Ukraine have indicated that many have made significant …


Whether you are a patient or a visitor, you are always welcome at The Ottawa Hospital. As a part of our commitment to quality care and patient safety, there are a few things you need to know before you visit.
The Ottawa Hospital supports patient and family-centered care. Family is an essential contributor to the healing process. That's why our visitor guidelines balance patients' needs with the health-care team's responsibilities to provide timely care.
Whether you're on staff, receiving outpatient care, or offering support to a sick relative, our long and short-term accommodation suites offer a comfortable, affordable stay in the Ottawa area.
The Ottawa Hospital offers a large selection of resources for you and your family, as well as ongoing support once your time at the hospital is over.
At The Ottawa Hospital, we are inspired every day by stories of hope from our patients and their families, as well as our health-care team.


text:
Q: State response given $A$ matrix and eigenvector matrix $M$ without using $M^{-1}$ This question is from a System Theory test without answers or solutions:
Consider the system $\dot{x}=Ax$, where
$A=\begin{bmatrix}-3&1&2&-1&1&0\\2&-2&0&2&-2&0\\0&0&0&0&0&0\\1&0&-1&0&-1&0\\-2&1&1&-1&0&0\\0&-1&1&1&0&-1 \end{bmatrix}$
with the eigenvalues given by $\lambda_{1,2}=-2,\ \lambda_{3,4}=0,\ \lambda_{5,6}=-1$ and the corresponding (generalized) eigenvectors given by
$M=\begin{bmatrix}m_1&m_2&m_3&m_4&m_5&m_6\end{bmatrix}=\begin{bmatrix}1&0&0&1&0&0\\0&1&1&1&0&0\\0&0&0&1&0&0\\0&0&1&0&0&1\\1&0&0&0&0&1\\0&1&0&0&1&1\end{bmatrix}$
Compute the state response $x(t)$ for $x_0=\begin{bmatrix}0&0&0&0&0&1\end{bmatrix}^\top$.
$\textbf{hint:}$ Do not compute $M^{-1}$
My approach:
The state response follows from $x(t)=e^{At}x_0$
Normally I would compute this using $e^{At}=MDM^{-1}$ in which
$D=\begin{bmatrix}e^{-2t}&0&0&0&0&0\\0&e^{-2t}&0&0&0&0\\0&0&1&0&0&0\\0&0&0&1&0&0\\0&0&0&0&e^{-t}&0\\0&0&0&0&0&e^{-t} \end{bmatrix}$
Using this method the state response is $\begin{bmatrix}0&0&0&0&0&e^{-t}\end{bmatrix}^{\top}$
An answer is not provided but I assume this to be correct.
But the hint bothers me.
I do not know how to achieve this result without computing/using $M^{-1}$

A: You could answer this even without knowing the eigenvalues and $M$. Namely $\dot{x}(0)=A\,x_0=-x_0$ also lies in the span of $x_0$, so $x(dt)$ should also remain in this span as well. From this it can be generalized that $x(t)$ for all $t>0$ will also remain in that span. From this it can be concluded that your proposed solution is indeed correct.
I do have to note that your expression for $D$ might not be correct, because due to the repeated eigenvalues you might be dealing with Jordan block of size bigger than one by one. To check this you could see if it holds that $A\,\vec{m} = \lambda\,\vec{m}$ for all eigenvalue (generalized)eigenvector pairs.

redpajama_set_name: RedPajamaStackExchange


At the Yadkin Valley Community School, our goal is to prepare students in mathematics for logical and critical thinking, not just the memorization of facts and formulas. Our lessons are designed as stepping stones for the student to learn mathematical concepts incrementally.
There are three fundamental concepts of mathematics that are taught in a linear fashion; the decimal system, the operations, and linear counting. Through the process of going from concrete to abstract and from building on easier to harder concepts, a sense of order is given. The whole program is taught by using manipulative so the retention of these concepts can then more readily take place versus just memorizing the process. Repetition is built into the curriculum as well, till all methods cumulate in the student's ability to work abstractly. The teacher follows the needs, styles, and abilities of the child to guide them to use their "mathematical tendency".
In the Upper Elementary classes, abstract work is a higher level of study, which comes naturally after the students have had numerous concrete examples and lessons. The Upper Elementary students learn to leave many of the concrete materials for the four basic operations behind, but continues to use materials for others, such as fractions and decimals. The focus turns to concepts and procedures for work with math topics. These topics include advanced study in geometry, fractions, statistics, decimals and basic algebra to name a few.