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The method for concentration of mineral matter at low temperature (about 250 °C), called Low Temperature Ash (LTA) was applied to a sample of coal from the mine ˵Las Mercedes″ located in Colombia southwestern. This method provides better information about the content of mineral matter in natural coal (NC), removing the organic matter more efficiently without significant transformations of mineral phases present in that coal. These results were observed through Mössbauer spectra and X-ray patterns taken from samples of NC, (LTA) and the conventional method of High Temperature Ash (HTA). The results show that the LTA process provides more representative data of the mineral phases for natural coal than that using the conventional HTA process. [ABSTRACT FROM AUTHOR]

The digital elevation model derived from SAR Interferometry is prone to atmospheric, penetration into soil medium, system noise and decorrelation errors. Eight ASAR images are selected for this study which have unique data set forming 7 InSAR pairs with single master image. It is expected that all the DEMs should have the same elevation values spatially with in the noise limits. However, they differ very much with one another beyond the noise levels indicating the effects of atmosphere and other disturbances. The 7 DEMs are compared with the DEM of SRTM for the estimation of errors. The spatial and temporal distribution of errors in DEM are analyzed by considering several case studies. [ABSTRACT FROM AUTHOR]

'tis, we musicians know, the C Major of this life. Paintings and museum reconstructions depicting the activities of medieval alchemists can easily give the wrong impression of the chemical knowledge of that period. Inanimate objects such as crystals are seen sharing shelves with the preserved bodies of small creatures, a common feature of the early laboratory. This could be taken to suggest that the scientists of those days had grasped the unity of chemistry: that in spite of great differences in their external appearance, Nature makes no distinction between chemical combinations in living and dead substances. Nothing could be farther from the truth. The universally held belief was that the matter contained in living organisms possessed an essential extra ingredient, a vital force, the mysterious origin of which was attributable to divine powers. This attitude was epitomized in the succinct classification to be found in the book Cours de Chyme, published by Nicholas Lemery in 1685. His division is still to be found in the standard first question of a popular parlour game: ‘animal, vegetable or mineral?’. By the end of the eighteenth century, the vital force theory was in rapid decline. Antoine Lavoisier, analyzing typical organic compounds, found them to contain inorganic substances such as hydrogen, oxygen, nitrogen, carbon, sulphur and phosphorus. The basic principles that govern chemical change, such as conservation of total mass, were being established during this period, and in 1844 Jöns Berzelius showed that they apply to all matter irrespective of whether it is inorganic or organic. [ABSTRACT FROM AUTHOR]

Gold is for the mistress – silver for the maid – Copper for the craftsman cunning at his trade. ‘Good!’ said the Baron, sitting in his hall, ‘But Iron – Cold Iron – is master of them all.’ It is no exaggeration to say that of all the materials in common use none have had a greater influence on our technological development than metals. Their unique combination of ductility and high electrical and thermal conductivity, together with their ready alloying, qualifies them to play a role for which there is no stand-in. Although they were not the first substances to be pressed into service, their use does go back at least 8000 years. The order in which the various metallic elements were discovered was inversely related to the ease with which they form compounds with the non-metals, particularly oxygen. Thus, with the possible exception of meteoric iron, the first metals known to man were probably gold, silver and copper, these being the only three common examples that actually occur as the metallic element. Conversely, there are metals which so tenaciously hold on to oxygen that they were not extracted from their ores until quite recently. One can imagine early man being attracted by the glint of gold nuggets, and he must have been intrigued by their ease of deformation compared with the brittleness of flint and other stones. The major use of gold has been in ornamentation. [ABSTRACT FROM AUTHOR]

All things began in order, so shall they end, and so shall they begin again; according to the ordainer of order and mystical mathematics of the city of heaven. Until now, our discussion has concerned isolated atoms and clusters of very few atoms. Considering that a single cubic centimetre of a typical piece of condensed matter, a block of stainless steel for example, contains approximately 1023 atoms, we see that there is still a long way to go in the description of actual substances. We must now inquire how large numbers of atoms are arranged with respect to one another, so as to produce the great variety of known materials. It will transpire that the observed arrangements are dictated both by the forces between atoms and the prevailing physical conditions. Before going into such details, however, it will be useful to examine the simple geometrical aspects of the question. It is frequently adequate to regard atoms as being spherical. The two-dimensional equivalent of a sphere is a circle, so we can begin by considering the arrangement of circles on a piece of paper. The circles could be drawn at random positions, well spread out and with close encounters occurring only by occasional chance. This is a reasonable representation of the instantaneous situation in a simple monatomic gas. A variant of this drawing would replace the single circles by small groups of circles, and we would then have a molecular gas. [ABSTRACT FROM AUTHOR]

Two of Vygotsky's (1997) central theoretical points are that cultural- historically developed tools mediate the child's relation to the world and that the competence to handle such tools is acquired in social settings through guidance from others. His theory of concept formation for preschoolers, schoolchildren, and adolescents explains how the practice of institutional activities influences children's concept formation (Vygotsky, 1987, 1998a). Small children participate in the everyday activities at home; schoolchildren meet the academic world in school, which he points out as a necessity for schoolchildren's development of scientific concepts; and adolescents get acquainted with the activities in work life, a necessity for their development of dialectical concepts. Vygotsky describes how very young children appropriate concepts of tools and objects through interaction with their caregivers and, as an example, he exemplifies this with how a child learns to use a spoon in interaction with his caregivers (Kravtsov & Berezlizhkaya, 1999). In his theory, Vygotsky characterizes small children's and preschool children's concepts as everyday concepts developed spontaneously in collaboration with others through everyday activities. He contrasts these concepts to schoolchildren's concepts, which he characterizes as scientifically developed through systematic school instruction. Although Vygotsky describes the concept learning of preschool children as inscribed in the social practice of everyday activities, what he primarily draws on when describing preschool children's concept formation is an experiment with the double-stimulation method (Vygotsky, 1987 p. 130ff). In this experiment, children's task is to sort blocks that vary in form, size, and color, gradually finding the sorting principle because a meaningless label is attached to the bottom of each block that is turned over each time the child has chosen one. [ABSTRACT FROM AUTHOR]

There are many reasons why it is difficult for readers to analyze and to understand Vygotsky's terminology. He developed his psychology in a direct and indirect dialogue with many other authors. In doing so, he absorbed and processed all the ideas and terms that he believed could be useful. These ideas ranged from the philosophy of Spinoza and Marx to the American behaviorism of Watson and the linguistics of Sapir. However, when one meets a seemingly familiar term borrowed from some predecessor in Vygotsky's writings, one should keep in mind that he was likely to have modified the term's meaning. Another motivation for a logico-semantic analysis of Vygotsky's writings is the quantity, variety, and nature of his scientific heritage. A 1960 bibliography of Vygotsky's works includes 274 titles (Vygotsky, 1960). Excluding nonscientific articles and notes devoted for the most part to the events of literary and theatrical life (1916-1923), there remain around 190 works in psychology, written from 1924 until Vygotsky's death (June 11, 1934): a period of only ten years. Many items from this decade were written very quickly, in almost telegraphic style. Some works remain unfinished. It is certainly possible that some of the works that were published posthumously were not yet intended for publication (unfortunately, the editors of contemporary editions do not always warn the reader about the state and nature of the original texts). Therefore, when reading Vygotsky's works one needs to remember his own words (from a letter to A. N. Leontiev dated July 31, 1930), “our writings are imperfect but there is great truth in them. This is my symbol of faith. . . . ” (Vygotsky, 1960, p. 169). [ABSTRACT FROM AUTHOR]

ABSTRACT A wealth of data exists for the American Southwest on diet, health, settlement, and other aspects of life in the precolonial and colonial periods. TheWestern Hemisphere project provided a way to begin to synthesize these data on a regional and comparative scale. The health index, as the average of the quality-adjusted life-years lived by a group (that is, the combined effects of morbidity and mortality), demonstrates that individuals in the Southwest carried a morbidity burden higher than most of the other areas discussed in this volume. Mortality is high and morbidity is ubiquitous. The combination of these two related processes resulted in a health index score of 16.5/26.4 or 62.5%. The mean age at death of approximately 24 years suggests that Southwest groups were on the lower end of the mortality spectrum. Comparison of comparable data sets provides a dimension of analysis in the Southwest not previously possible, and as such, presents important additional information for the interpretation of health in the American Southwest. INTRODUCTION In pre–Columbian times, the Greater Southwest was a biogeographically, culturally, and politically complex area incorporating Arizona, New Mexico, and southern Utah and Colorado in the United States, as well as all the states of northern Mexico, including Chihuahua, Sonora, and Durango. It was then, and continues to be, a cultural, political, and economically diverse area where contact, trade, and boundary maintenance and dispute define local and regional interactions. The Southwest is also a place where semiarid desert landscapes abound. Water is at a premium, and arable land is a limited resource. [ABSTRACT FROM AUTHOR]

Galileo's conflict with the Roman Catholic Church has long held a very special fascination. The prime reason for this, of course, is that the Galileo affair has come to be seen as the paradigm case of the troubled interaction between science and religion. Another reason is the sheer dramatic power of the events involved, which continue to attract the attention of the scholar, the novelist, and the playwright. Images easily multiply of the flawed tragic hero, of the struggle for intellectual freedom, of the unprotected individual pitted against a powerful institution committed to its selfpreservation, and of plots and subplots and counterplots worthy of the best mystery writer. [ABSTRACT FROM AUTHOR]

Galileo's researches in astronomy were more than original, they were unprecedented. He was not an astronomer in the sense of Copernicus, Tycho, and Kepler, making observations, devising models, and deriving parameters in order to compute tables and ephemerides for finding the positions of the Sun, Moon, and planets. Nor did he search for the physical principles governing the motions of the heavens as Kepler and later Newton did. Most of his work was concerned with two issues, the refutation of the Aristotelian and the defense of the Copernican “System of the World”, and his originality lies not so much in what he found as in how he interpreted his discoveries. Even his discoveries with the telescope, as interesting as they are in themselves - and it is hard to think of more surprising discoveries in the entire history of science - are of still greater interest for the conclusions that he drew from them, for nearly all of them could be turned to the criticism of Aristotle and the defense of Copernicus, and in his Dialogue on the Two Great Systems of the World that is just what Galileo did. Our concern here, however, is with his initial discoveries and his initial interpretations, which, although not as far-reaching as the conclusions he reached in the Dialogue, were upsetting enough to anyone who was not already a friend of Copernicus. [ABSTRACT FROM AUTHOR]

Galileo is one of the larger than life heroes of history. This status was conferred during his lifetime and grew with each succeeding century. Not only was he the hero of the Scientific Revolution, but after his troubles with the Catholic Church he became the hero of science. Today, only the names of Newton and Einstein rival that of Galileo in popularity and imagination. But yet we must ask, to what is his popularity due? What did Galileo actually do that made his image so great and so long-standing? [ABSTRACT FROM AUTHOR]

The aura surrounding Galileo as founder of modern science disposes many of those writing about him to start in medias res with an account of his discoveries with the telescope, or with his dialogues on the world systems and the two new sciences, or with the trial and the tragic events surrounding it. Frequently implicit in such beginnings is the attitude that Galileo had no forebears and stands apart from history, this despite the fact that he was forty-six years of age when he wrote his Sidereus Nuncius and then in his late sixties and early seventies when he composed his two other masterpieces. [ABSTRACT FROM AUTHOR]