903 resultados para Classificació AMS::01 History and biography::01A History of mathematics and mathematicians


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In this contribution I look at three episodes in the history of neurophysiology that bring out the complex relationship between seeing and believing. I start with Vesalius in the mid-sixteenth century who writes that he can in no way see any cavity in nerves, even in the optic nerves. He thus questions the age-old theory (dating back to the Alexandrians in the third century BC) but, because of the overarching psychophysiology of his time, does not press his case. This conflict between observation and theory persisted for a quarter of a millennium until finally resolved at the beginning of the nineteenth century by the discoveries of Galvani and Volta. The second case is provided by the early history of retinal synaptology. Schultze in 1866 had represented rod spherules and bipolar dendrites in the outer plexiform layer as being separated by a (synaptic) gap, yet in his written account, because of his theoretical commitments, held them to be continuous. Cajal later, 1892, criticized Schultze for this pusillanimity, but his own figure in La Cellule is by no means clear. It was only with the advent of the electron microscopy in the mid-twentieth century that the true complexity of the junction was revealed and it was shown that both investigators were partially right. My final example comes from the Hodgkin-Huxley biophysics of the 1950s. Their theory of the action potential depended on the existence of unseen ion pores with quite complex biophysical characteristics. These were not seen until the Nobel-Prize-winning X-ray diffraction analyses of the early twenty-first century. Seeing, even at several removes, then confirmed Hodgkin and Huxley’s belief. The relation between seeing and believing is by no means straightforward.

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Higher education always plays an important role in the development of a nation. Taiwan is no exception. Graduates of the National Taiwan University have occupied most of the important positions in this country and today many devote themselves to the development of Taiwan since the central government of the Republic of China (ROC) withdrew from Mainland China and re-located to Taiwan in the winter of 1949. The higher education system in Taiwan, including university and junior colleges, received special attention from the government except from 1945 to 1949 during the transitional period; the time of the early restoration year and the central government's retreating period from Mainland China.^ The five presidents of National Taiwan University who served from 1949 to 1993, Fu Szu-nien, Chien Seu-liang, Yen Chen-Hsing, Yu Chao-chung, and Sun Chen, are the subject of this research. All of the presidents were appointed by the government which established a direct connection between the government and the university leadership. The purpose of this study is to understand how each president balanced politically assigned roles and expectations with personal visionary academic responsiveness to the principles which define the university.^ Each president and his tenure were analyzed using historical research, a developed leadership model, an integration of role theory, Locke's leadership model, Wiles and Bondi curriculum leader tasks, and Burn's leadership style. Results of analyses of documents showed that all presidents of the National Taiwan University were highly respected due to their academic background, personal characteristics, and contribution to the university as a leader. Meanwhile, implementation and achievement of the presidents led to the conclusion that appointed university presidents had significant relationships with government policy. Their leadership style was affected strongly by their personal traits and knowledge and the social and political climate of the time. ^

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Effective school board leadership is often an ephemeral ideal in today's highly politicized public education arena. However, effective leadership is necessary in order to ensure a fair and equitable education for all students. This dissertation described and explained one school board member's perspective of his career as a lens from which to view and assess public educational policy making in Miami-Dade County. ^ Now retired after thirty-eight years of service, G. Holmes Braddock is the longest serving, contemporary, urban school board member in the country. Spanning nearly four decades, his perspective provides a comprehensive view of urban education both locally and nationally. The significance of his longevity and the impact of his leadership on educational policy-making was the focus of indepth interviews with Mr. Braddock and other key educational “influentials.” From this transcript data, recurring themes were revealed and categorized. Five elements of his perspective, i.e., teacher professionalization; desegregation; athletics; bilingual education; and his comprehensive leadership role, were identified and analyzed, as were five variables of his perspective, i.e., fairness; integrity; honesty; courage; and the situational context. Other secondary source material, such as excerpts from newspaper articles, school board minutes, and items from Mr. Braddock's own personal effects further augmented and triangulated the data. ^ Given that the purpose of this study was to describe and explain Mr. Braddock's perspective of his school board career, the findings can be understood from two different viewpoints. The elements of Mr. Braddock's perspective describe or characterize his career and represent the significant policy issues in which he demonstrated exceptional vision and leadership. However, taken alone, these elements cannot fully explain his distinguished career. Rather, an analysis of the variables of Mr. Braddock's perspective provides an explanation for the effectiveness of his leadership role. Personality traits such as fairness, integrity, honesty and courage and the impact of the situational context were factors that strongly influenced Mr. Braddock's decision-making. Thus, Mr. Braddock's school board career can be holistically understood as the intersection of person, place and time with significant public education policy issues. ^ The results of this study provide a unique and historical perspective of school board politics in Miami-Dade County. From Mr. Braddock's perspective, we are able to view one individual's leadership role over time and its impact on local public education policy. ^

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This dissertation is about commercial agriculture in nineteenth-century Liberia. Based primarily on the archives of the American Colonization Society (founder of Liberia), it examines the impact of environmental and demographic constraints on an agrarian settler society from 1822 to the 1890s. Contrary to the standard interpretation, which linked the poor state of commercial agriculture to the settlers' disdain for cultivation, this dissertation argues that the scarcity of labor and capital impeded the growth of commercial agriculture. The causes of the scarcity were high mortality, low immigration and the poverty of the American “Negroes” who began to settle Liberia in 1822. ^ Emigration to Liberia meant almost certain death and affliction for many immigrants because they encountered a new set of diseases. Mortality was particularly high during the early decades of colonization. From 1822 to 1843, about 48 percent of all immigrants died of various causes, usually within their first year. The bulk of the deaths is attributed to malaria. There was no natural increase in the population for this early period and because American “Negroes” were unenthusiastic about relocation to Liberia, immigration remained sparse throughout the century. Low immigration, combined with the high death rate, deprived the fledgling colony of its potential human resource, especially for the cultivation of labor-intensive crops, like sugar cane and coffee. Moreover, even though females constituted approximately half of the settlers, they seldom performed agricultural labor. ^ The problem of labor was compounded by the scarcity of draft animals. Liberia is in the region where trypanosomiasis occurs. The disease is fatal to large livestock. Therefore, animal-drawn plows, common in the United States, were never successfully transplanted in Liberia. Besides, the dearth of livestock obstructed the development of the sugar industry since many planters depended on oxen-powered mills because they could not afford to buy the more expensive steam engine mills. ^ Finally, nearly half of the immigrants were newly emancipated slaves. Usually these former bondsmen arrived in Liberia penniless. Consequently, they lacked the capital to invest in large-scale plantations. The other categories of immigrants (e.g., those who purchased their freedom), were hardly better off than the emancipated slaves. ^

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This multi-disciplinary research project explores the religious and cultural foundations within the "master commemorative narratives" that frame Israeli and Iranian political discourse. In articulating their grievances against one another, Israeli and Iranian leaders express the tensions between religion, nationalism, and modernity in their own societies. The theoretical and methodological approach of this dissertation is constructivist-interpretivist. The concept of "master commemorative narratives" is adapted from Yael Zerubavel's study of ritualized remembrance in Israeli political culture, and applied to both Israeli and Iranian foreign policy. Israel’s master commemorative narrative draws heavily upon the language of the Hebrew Bible, situating foreign policy discourse within a paradigm of covenantal patrimony, exile, and return, despite the unrelenting hostility of eternal enemies and "the nations." Iran’s master commemorative narrative expresses Iranian suspicion of foreign encroachment and interference, and of the internal corruption that they engender, sacralizing resistance to the forces of evil in the figurative language and myths of pre-Islamic tradition and of Shi'a Islam. Using a constructivist-interpretive methodological approach, this research offers a unique interpretive analysis of the parallels between these narratives, where they intersect, and where they come into conflict. It highlights both the broad appeal and the diverse challenges to the components of these "master" narratives within Israeli and Iranian politics and society. The conclusion of this study explains the ways in which the recognition of religious and cultural conflicts through the optic of master commemorative narratives can complement the perspectives of other theoretical approaches and challenge the conventions of Security Studies. It also suggests some of the potential practical applications of this research in devising more effective international diplomacy.

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Tobacco was of primary importance to Spain, and its impact on Cuba's economy and society was greater than just the numbers of farms, workers, or production, demonstrated by the Spanish crown's outlay of monies for capital assets, bureaucrats' salaries, and payments to farmers for their crop. This study is a micro- and macro-level study of rural life in colonial Cuba and the interconnected relationships among society, agricultural production, state control, and the island's economic development. ^ By placing Cuba's tobacco farmers at the forefront of this social history, this work revisits and offers alternatives to two prevailing historiographical views of rural Cuba from 1763 (the year Havana returned to Spanish control following the Seven Years' War) to 1817 (the final year of the 100-year royal monopoly on Cuban tobacco). Firstly, it argues against the primacy of sugar over other agricultural crops, a view that has shaped decades of scholarship, and challenges the thesis which maintains the Cuban tobacco farmer was almost exclusively poor, white, and employed free labor, rather than slaves, in the production of their crop. ^ This study establishes the importance of tobacco as an agricultural product, and argues that Cuban tobacco growers were a heterogeneous group, revealing the role that its cultivation may have played in helping some slaves earn their freedom. ^

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Morocco was the last North African country in which a Pasteur institute was created, nearly two decades later than in Tunisia and Algeria. In fact, two institutes were opened, the first in Tangier in 1913 and the second in Casablanca in 1932. This duplication, far from being a measure of success, was the material expression of the troubles Pastorians had experienced in getting a solid foothold in the country since the late 19th century. These problems partly derived from the pre-existence of a modest Spanish-Moroccan bacteriological tradition, developed since the late 1880s within the framework of the Sanitary Council and Hygiene Commission of Tangier, and partly from the uncoordinated nature of the initiatives launched from Paris and Algiers. Although a Pasteur Institute was finally established, with Paul Remlinger as director, the failure of France to impose its colonial rule over the whole country, symbolized by the establishment of an international regime in Tangier, resulted in the creation of a second centre in Casablanca. While elucidating many hitherto unclear facts about the entangled origins of both institutes, the author points to the solidity of the previously independent Moroccan state as a major factor behind the troubled translation of Pastorianism to Morocco. Systematically dismissed or downplayed by colonial and postcolonial historiography, this solidity disrupted the French takeover of the country and therefore Pastorian expectations.

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We studied the ecology and natural history of the globally threatened and poorly known Akodon lindberghi Hershkovitz, 1990 in Parque Nacional da Serra da Canastra (PNSC) and Juiz de Fora (JF), southeastern Brazil. From November 1998 to September 2001 a total of 131 individuals were captured in wire-cage live-traps and 52 by pitfalls traps. They were all marked and released at the site. The largest abundances were registered during the dry season, and most of the captures occurred in open habitats. The mean body mass of the two populations was significantly different (18.1 g at PNSC versus 13.1 g at JF; H = 46.2678, g.l.=2, p<0.001). In PNSC, individuals were reproductively active from August to February, and juveniles were present from May to August. The results suggest that the changes in vegetation structure caused by deforestation and intensive agricultural activities could increase the predation rate, affecting the mean body mass of the population.

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O objetivo foi estimar as regressões de calibração dos dados dietéticos mensurados pelo questionário quantitativo de freqüência alimentar (QQFA) utilizado no Natural History of HPV Infection in Men: o Estudo HIM. Uma amostra de 98 indivíduos do estudo HIM respondeu, por meio de entrevista, a um QQFA e três recordatórios de 24 horas (R24h). A calibração foi feita por meio de análise de regressão linear, tendo os R24h como variável dependente e o QQFA como variável independente. Idade, índice de massa corporal, atividade física, renda e escolaridade foram utilizadas como variáveis de ajuste nos modelos. As médias geométricas dos R24h e do QQFA corrigido pela calibração são estatisticamente iguais. Os gráficos de dispersão entre os instrumentos demonstraram aumento da correlação após a correção dos dados, porém observa-se maior dispersão dos pontos de acordo com a piora do poder explicativo dos modelos. A identificação das regressões de calibração dos dados dietéticos do estudo HIM permitirá a estimativa do efeito da dieta sobre a infecção por HPV, corrigida pelo erro de medida do QQFA

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This article is an introduction to the special issue of Sexuality Research & Social Policy, where we share some of the research of our project, ""Relations among 'race,' sexuality and gender in different local and national contexts."" The goal of this project was to develop broad comparative research on race, sexuality, and gender in Brazil, South Africa, and the USA. New signs of identity and contestation were noted during our research. Given the numerous and important changes which are currently in progress in these interlinked fields, we identified important connections between transformations in the symbolic order and social gains, which cannot necessarily be converted into more widespread decreases in social inequality or which can break apart forms of hierarchization and exclusion. The results of our studies in South Africa and Brazil are the focus of this special issue, given that these two contexts are less well known by the American public.

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Background: Diabetic neuropathy leads to progressive loss of sensation, lower-limb distal muscle atrophy, autonomic impairment, and gait alterations that overload feet. This overload has been associated with plantar ulcers even with consistent daily use of shoes. We sought to investigate and compare the influence of diabetic neuropathy and plantar ulcers in the clinical history of diabetic neuropathic patients on plantar sensitivity, symptoms, and plantar pressure distribution during gait while patients wore their everyday shoes. Methods: Patients were categorized into three groups: a control group (CG; n = 15), diabetic patients with a history of neuropathic ulceration (DUG; n = 8), and diabetic patients without a history of ulceration (DG; n = 10). Plantar pressure variables were measured by Pedar System shoe insoles in five plantar regions during gait while patients wore their own shoes. Results: No statistical difference between neuropathic patients with and without a history of plantar ulcers was found in relation to symptoms, tactile sensitivity, and duration of diabetes. Diabetic patients without ulceration presented the lowest pressure-time integral under the heel (72.1 +/- 16.1 kPa x sec; P=.0456). Diabetic patients with a history of ulceration presented a higher pressure-time integral at the midfoot compared to patients in the control group (59.6 +/- 23.6 kPa x sec x 45.8 +/- 10.4 kPa x sec; P = .099), and at the lateral forefoot compared to diabetic patients without ulceration (70.9 +/- 17.7 kPa sec x 113.2 +/- 61.1 kPa x sec, P = .0193). Diabetic patients with ulceration also presented the lowest weight load under the hallux (0.06 +/- 0.02%, P = .0042). Conclusions: Although presenting a larger midfoot area, diabetic neuropathic patients presented greater pressure-time integrals and relative loads over this region. Diabetic patients with ulceration presented an altered dynamic plantar pressure pattern characterized by overload even when wearing daily shoes. Overload associated with a clinical history of plantar ulcers indicates future appearance of plantar ulcers. (J Am Podiatr Med Assoc 99(4): 285-294, 2009)