1,526 research outputs found

    Arctic Townsmen: Ethnic Backgrounds and Modernization, by John J. and Irma Honigmann

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    Map Making of the North Alaskan Eskimo

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    The German Paradox (A Problem in National Character)

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    ABSTRACT - There has been considerable argument since World War II over whether the concept of a national character, such as might distinguish the Germans, the Japanese, the Russians, or any other contemporary national group, has any reality in fact. The present paper, operating on the assumption that there is a distinctive German character, one essentially different from that of the English, the Italians, the French, or the Russians, seeks to show, in terms of the processes of culture defined by anthropology, where German uniqueness lies. This, it is contended, rests not so much in factors of native psychology and social organization as it does in geographic position and in the German position in the stream of European history. The marginal position of the Germans, both in time and space, is a vital element in producing both excellence and excess

    Effect of head injury on fracture healing : clinical and experimental studies

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    The Eskimo of North Alaska, by Norman A. Chance

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    Some Relations of School and Family in American Culture

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    Virtually any statement made about the contemporary American system of education can be subjected to infinite documentation. What the school should accomplish, what is has accomplished, what its curricula ought to be, how far it should or has become a kind of surrogate for the family, church or other institution, emerge as vital questions for the professional educators, questions, clearly, for which there is no single answer. Judgments become normative, ameliorative, critical, and certainly, nearly always fraught with overtones of emotionalism. This leaves the non-specialist who attempts to gain an over-view of the nature and image of the educator and his field in the dilemma of adequately finding his way. Still, the school is a social institution. As such, it can be subjected to analysis in quite the same behavioral terms as any other human group activity. Rather, therefore, than to move into the areas of the ideal-what a school and the system associated with it ought to be---it may be possible to consider the educational institutions in terms of their structure and function, thereby analyzing the interrelations between school system and other institutional facets of contemporary society. This paper is written from the point of view of the behavioral sciences, specifically, from the vantage point of the anthropologist whose concern lies in the comparison of the various aspects of human behavior at all times and places. For indeed, if a society seeks to learn about itself, it gains perspective only through an observation of alternative solutions to human problems which have been reached by human groups possessing different historical backgrounds and whose view of man, his nature and destiny, is couched in fundamental assumptions and premises different from those of Homo americanus

    Heat Transfer to Fuel Sprays Injected into Heated Gases

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    This report presents the results of a study made of the influence of several variables on the pressure decrease accompanying injection of a relatively cool liquid into a heated compressed gas. Indirectly, this pressure decrease and the time rate of change of it are indicative of the total heat transferred as well as the rate of heat transfer between the gas and the injected liquid. Air, nitrogen, and carbon dioxide were used as ambient gases; diesel fuel and benzene were the injected liquids. The gas densities and gas-fuel ratios covered approximately the range used in compression-ignition engines. The gas temperatures ranged from 150 degrees c. to 350 degrees c

    Sources of residual autocorrelation in multiband task fMRI and strategies for effective mitigation

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    In task fMRI analysis, OLS is typically used to estimate task-induced activation in the brain. Since task fMRI residuals often exhibit temporal autocorrelation, it is common practice to perform prewhitening prior to OLS to satisfy the assumption of residual independence, equivalent to GLS. While theoretically straightforward, a major challenge in prewhitening in fMRI is accurately estimating the residual autocorrelation at each location of the brain. Assuming a global autocorrelation model, as in several fMRI software programs, may under- or over-whiten particular regions and fail to achieve nominal false positive control across the brain. Faster multiband acquisitions require more sophisticated models to capture autocorrelation, making prewhitening more difficult. These issues are becoming more critical now because of a trend towards subject-level analysis, where prewhitening has a greater impact than in group-average analyses. In this article, we first thoroughly examine the sources of residual autocorrelation in multiband task fMRI. We find that residual autocorrelation varies spatially throughout the cortex and is affected by the task, the acquisition method, modeling choices, and individual differences. Second, we evaluate the ability of different AR-based prewhitening strategies to effectively mitigate autocorrelation and control false positives. We find that allowing the prewhitening filter to vary spatially is the most important factor for successful prewhitening, even more so than increasing AR model order. To overcome the computational challenge associated with spatially variable prewhitening, we developed a computationally efficient R implementation based on parallelization and fast C++ backend code. This implementation is included in the open source R package BayesfMRI.Comment: 26 pages with 1 page of appendix, 11 figures with 1 figure of supplementary figur

    Antibiotic additives alter the static and viscoelastic properties of bone cements

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    Introduction: In arthroplasty antibiotics are added to bone cements to prevent deep infection. The static properties of plain and antibiotic laden cements have been extensively described in the literature [1]. Commercially available cements must perform above the minimum values set by ISO 5833:2002 [2]. However, no upper or lower limits are set for the viscoelastic properties of the cements, despite this being a recognised factor affecting the cement-implant performance [3]. The ability of acrylic bone cement to creep and stress relax in conjunction with forceclosed stems in hip arthroplasty affords protection of the vital bone-cement interface. With this design subsidence of the stem within the cement mantle over time does not lead to clinical failure [4]. Conversely, the clinical performance of shapeclosed stem designs can be negatively affected by cements demonstrating excessive creep. This study investigated the effect of antibiotic additives on the static and viscoelastic properties of PMMA cement. Materials and Methods: The mechanical and viscoelastic properties of Simplex P, Simplex Antibiotic and Simplex Tobramycin (Stryker, Limerick, IE) were investigated. This family of cements was chosen as they are characterised by the same polymeric base, that of Simplex P, the plain formulation, but contain different antibiotic additives. In particular Simplex Antibiotic contains 0.5g Erythromycin and 3 million I.U. Colistin, while in Simplex Tobramycin the only additive is 0.5g of Tobramycin. The static properties of the cements (compressive strength, bending strength and bending modulus) were assessed following ISO 5833:2002 [2], while stress relaxation and creep were assessed under quasi static conditions in a four pointbending configuration. The creep experiments were carried out using a custom made apparatus with the specimens positioned in a distilled water bath at 37 o
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