871 resultados para scalable to larger studies
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Mode of access: Internet.
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Tozer, H.F. Geography.--Tristram, H.B. Fauna.--Tristram, H.B. Flora.--History: 1. Hicks,R.D. Chronology. 2. Chronological Tables.--Jebb, Sir R. Literature.--Philosophy: 1. Jackson, H. Schools to Aristotle. 2. Hicks, R.D. Later Schools.--Gow, J. Science.--Art: 1. Penrose, F.C. Architecture. 2. Waldstein, C. Prehistoric art. 3. Waldstein, C. Sculpture. 4. Earp, F.R. Painting. 5. Smith, A.H. Vase Painting. 6. Smith, A.H. Terracottas. 7. Ridgeway, W. Engraved gems. 8. Hind, R.D. Archer--Music.--Gardner, E.A. Mythology and religion.--Public antiquities: 1. Whibley, L. Constitutions. 2. Wyse, W. Law. 3. Wyse, W. Finance. 4. Mayor, R.J.G. Population. 5. Mayor, R.J.G. Slaves and slavery. 6. Edwards, H.J. Colonies. 7. Edwards, H.J. Commerce and industry. 8. Ridgeway, W. Measures and weights. 9. Ridgeway, W. Money. 10. Oman, C.W.C. War. 11. Cook, A.B. Ships. 12. Gow, J. The calendar.--Private antiquities: 1. Gow, J. A table of the relationships of a man. 2. Harrison, Miss J. Ritual of birth, marriage, and death. 3. Wilkins, A.S. Education. 4. James, M.R. Books and writing. 5. Cornish, F.W. The position of women. 6. Evans, Lady Dress. 7. Gardner, E.A. Daily life, its surroundings, employments and amusements. 8. Gardner, E.A. House and furniture. 9. Allbutt, T.C. Medicine.--Criticism and Interpretation: 1. Neil, R.A. Dialects. 2. Roberts, E.S. Epigraphy. 3. Harris, J.R. Palaeography. 4. Jebb, Sir R. Textual criticism. 5. Verrall, A.W. Metre. 6. Sandys, J.E. History of scholarship.--Indices.
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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Includes indexes.
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Includes bibliographies.
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Includes indexes.
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Personalized medicine will revolutionize our capabilities to combat disease. Working toward this goal, a fundamental task is the deciphering of geneticvariants that are predictive of complex diseases. Modern studies, in the formof genome-wide association studies (GWAS) have afforded researchers with the opportunity to reveal new genotype-phenotype relationships through the extensive scanning of genetic variants. These studies typically contain over half a million genetic features for thousands of individuals. Examining this with methods other than univariate statistics is a challenging task requiring advanced algorithms that are scalable to the genome-wide level. In the future, next-generation sequencing studies (NGS) will contain an even larger number of common and rare variants. Machine learning-based feature selection algorithms have been shown to have the ability to effectively create predictive models for various genotype-phenotype relationships. This work explores the problem of selecting genetic variant subsets that are the most predictive of complex disease phenotypes through various feature selection methodologies, including filter, wrapper and embedded algorithms. The examined machine learning algorithms were demonstrated to not only be effective at predicting the disease phenotypes, but also doing so efficiently through the use of computational shortcuts. While much of the work was able to be run on high-end desktops, some work was further extended so that it could be implemented on parallel computers helping to assure that they will also scale to the NGS data sets. Further, these studies analyzed the relationships between various feature selection methods and demonstrated the need for careful testing when selecting an algorithm. It was shown that there is no universally optimal algorithm for variant selection in GWAS, but rather methodologies need to be selected based on the desired outcome, such as the number of features to be included in the prediction model. It was also demonstrated that without proper model validation, for example using nested cross-validation, the models can result in overly-optimistic prediction accuracies and decreased generalization ability. It is through the implementation and application of machine learning methods that one can extract predictive genotype–phenotype relationships and biological insights from genetic data sets.
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The legacy of nineteenth century social theory followed a “nationalist” model of society, assuming that analysis of social realities depends upon national boundaries, taking the nation-state as the primary unit of analysis, and developing the concept of methodological nationalism. This perspective regarded the nation-state as the natural - and even necessary - form of society in modernity. Thus, the constitution of large cities, at the end of the 19th century, through the intense flows of immigrants coming from diverse political and linguistic communities posed an enormous challenge to all social research. One of the most significant studies responding to this set of issues was The Immigrant Press and its Control, by Robert E. Park, one of the most prominent American sociologists of the first half of the 20th century. The Immigrant Press and its Control was part of a larger project entitled Americanization Studies: The Acculturation of Immigrant Group into American Society, funded by the Carnagie Corporation following World War I, taking as its goal to study the so-called “Americanization methods” during the 1920s. This paper revisits that particular work by Park to reveal how his detailed analysis of the role of the immigrant press overcame the limitations of methodological nationalism. By granting importance to language as a tool uniting each community and by showing how the strength of foreign languages expressed itself through the immigrant press, Park demonstrated that the latter produces a more ambivalent phenomenon than simply the assimilation of immigrants. On the one hand, the immigrant press served as a connecting force, driven by the desire to preserve the mother tongue and culture while at the same time awakening national sentiments that had, until then, remained diffuse. Yet, on the other hand, it facilitated the adjustment of immigrants to the American context. As a result, Park’s work contributes to our understanding of a particular liminal moment inherent within many intercultural contexts, the space between emigrant identity (emphasizing the country of origin) and immigrant identity (emphasizing the newly adopted country). His focus on the role played by media in the socialization of immigrant groups presaged later work on this subject by communication scholars. Focusing attention on Park’s research leads to other studies of the immigrant experience from the same period (e.g., Thomas & Znaniecki, The Polish Peasant in Europe and America), and also to insights on multi-presence and interculturality as significant but often overlooked phenomena in the study of immigrant socialization.
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Mice infected with about 90 cercariae of Schistosoma mansoni (LE strain) were treated during five consecutive days with dexamethasone (50 mg/Kg, subcutaneously), starting on the 42th day of infection. Groups of five mice were then daily sacrificed from the first day after onset of treatment until the first day after. The perfusion of the portal system was performed and a piece of the intestine was processed for qualitative and quantitative oograms. This treatment carries to larger numbers of eggs in the tissues of treated mice, when compared with untreated groups. No changes were observed in the kinetics of oviposition, as all stages of viable eggs were observed in the tissues of treated and control mice. These data reinforce the hypothesis of a partial blockade of the egg excretion in immunossupressed mice.
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Introduction Exposure to hypoxia leads to several reactions of the organism, which try to compensate the reduced oxygen level in the blood. Acute response is characterized by an increase in pulmonary ventilation (Hypoxia Ventilatory Response, HVR) and in cardiac output (cardiac response to hypoxia). Heart rate (HR) at rest and during exercise is higher at high altitude than at sea level, whereas HRmax is lower. These cardiac adaptations are partially explained by an increased sympathetic stimulation associated with a reduced parasympathetic tone (12). The precise mechanisms of HRmax decline in acute hypoxia are however still to be identified, although several hypothesis have been suggested, such as a direct effect of hypoxia on the electrophysiological properties, an influence of skeletal maximal VO2 or a modulation of the autonomic nervous system (8). Some authors have reported that endurance trained athletes present an increased sensitivity to hypoxia shown by a large reduction in VO2max and an important decrease in arterial saturation. (9,11, 13) A hypoxia test can assess the sensibility of chemoreceptors to the reduction of oxygen by calculating hypoxic ventilatory and cardiac responses, knowing that low sensibility is correlated with poor acclimatization. Two parameters results from the differences in ventilation (and heart rate) divided by the difference in the arterial oxygen saturation between normoxia and hypoxia (18). Objective The hypothesis tested by this study is that parasympathetic reactivation after moderate effort in hypoxic condition can be used as a marker of individual sensibility to hypoxia. Parasympathetic reactivation is a marker of vagal tone that predict endurance capacity and aerobic fitness (2,7). Methods Subjects This study uses data obtained from two groups of athletes participating into two larger studies about adaptation to hypoxia. One group is composed of elite athletes (Swiss ski mountaineering team), the other one of mid-level athletes (ski mountaineering amateurs). The particularity of this target population is that they often train at high altitude, and therefore could show a better response to hypoxia than athleltes of other disciplines. Protocol The athletes performed a submaximal exercise (6min run at 9 km/h, flat) followed by 10 min of seated rest either in an hypoxic chamber (simulated altitude of 3000m) or in normoxic conditions. During the resting phase parasympathetic reactivation was assessed by beat-to-beat HR measurements.A test of tolerance to altitude was also performed. Analysis Parasympathetic reactivation, assessed by the calculation of the root mean square of successive differences in the R-R intervals (RMSSD)(4), is compared to individual responses at altitude, in order to appreciate the correlation between the two phenomena.
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Virtually every cell and organ in the human body is dependent on a proper oxygen supply. This is taken care of by the cardiovascular system that supplies tissues with oxygen precisely according to their metabolic needs. Physical exercise is one of the most demanding challenges the human circulatory system can face. During exercise skeletal muscle blood flow can easily increase some 20-fold and its proper distribution to and within muscles is of importance for optimal oxygen delivery. The local regulation of skeletal muscle blood flow during exercise remains little understood, but adenosine and nitric oxide may take part in this process. In addition to acute exercise, long-term vigorous physical conditioning also induces changes in the cardiovasculature, which leads to improved maximal physical performance. The changes are largely central, such as structural and functional changes in the heart. The function and reserve of the heart’s own vasculature can be studied by adenosine infusion, which according to animal studies evokes vasodilation via it’s a2A receptors. This has, however, never been addressed in humans in vivo and also studies in endurance athletes have shown inconsistent results regarding the effects of sport training on myocardial blood flow. This study was performed on healthy young adults and endurance athletes and local skeletal and cardiac muscle blod flow was measured by positron emission tomography. In the heart, myocardial blood flow reserve and adenosine A2A receptor density, and in skeletal muscle, oxygen extraction and consumption was also measured. The role of adenosine in the control of skeletal muscle blood flow during exercise, and its vasodilator effects, were addressed by infusing competitive inhibitors and adenosine into the femoral artery. The formation of skeletal muscle nitric oxide was also inhibited by a drug, with and without prostanoid blockade. As a result and conclusion, it can be said that skeletal muscle blood flow heterogeneity decreases with increasing exercise intensity most likely due to increased vascular unit recruitment, but exercise hyperemia is a very complex phenomenon that cannot be mimicked by pharmacological infusions, and no single regulator factor (e.g. adenosine or nitric oxide) accounts for a significant part of exercise-induced muscle hyperemia. However, in the present study it was observed for the first time in humans that nitric oxide is not only important regulator of the basal level of muscle blood flow, but also oxygen consumption, and together with prostanoids affects muscle blood flow and oxygen consumption during exercise. Finally, even vigorous endurance training does not seem to lead to supranormal myocardial blood flow reserve, and also other receptors than A2A mediate the vasodilator effects of adenosine. In respect to cardiac work, atheletes heart seems to be luxuriously perfused at rest, which may result from reduced oxygen extraction or impaired efficiency due to pronouncedly enhanced myocardial mass developed to excel in strenuous exercise.