1,190 research outputs found

    Precis of Vaulting Ambition: Sociobiology and the Quest for Human Nature

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    The debate about the credentials of sociobiology has persisted because scholars have failed to distinguish the varieties of sociobiology and because too little attention has been paid to the details of the arguments that are supposed to support the provocative claims about human social behavior. I seek to remedy both dcfieieneies. After analysis of the relationships among different kinds of sociobiology and contemporary evolutionary theory, I attempt to show how some of the studies of the behavior of nonhuman animals meet the methodological standards appropriate to evolutionary research. I contend that the efforts of E. O. Wilson, Richard Alexander, Charles Lumsden, and others to generate conclusions about human nature are flawed, both because they apply evolutionary ideas in an unrigorous fashion and because they use dubious assumptions to connect their evolutionary analyses with their conclusions. This contention rests on analyses of many of the major sociobiological proposals about human social behavior, including: differences in sex roles, racial hostility, homosexuality, conflict between parents and adolescent offspring, incest avoidance, the avunculate, alliances in combat, female infanticide, and gene-culture coevolution. Vaulting Ambition thus seeks to identify what is good in sociobiology, to expose the errors of premature speculations about human nature, and to prepare the way for serious study of the evolution of human social behavior

    Disc: A Continuing Dilemma

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    Définition macroscopique des unités lithostratigraphiques de l’Oxfordien moyen au Kimméridgien en Ajoie (Jura suisse): Nouvelles données acquises dans le cadre de la construction de l’autoroute A16

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    La mise sur pied en 2000 d’une section paléontologique (Paléontologie A16) en lien avec la construction de l’A16 (Transjurane), a permis la mise au jour de nombreux affleurements du Jurassique supérieur en Ajoie. De nouveaux profils sédimentologiques ont été levés grâce aux fouilles paléontologiques, aux travaux autoroutiers, à l’ouverture de nouvelles carrières et à la réalisation de forages. Un échantillonnage important a été réalisé à cette occasion. Ces nouvelles données et observations permettent aujourd’hui de préciser le découpage lithostratigraphique et l’évolution latérale des faciès carbonatés de la fin du Jurassique en Ajoie. Deux nouveaux noms de membre sont proposés pour la formation de Reuchenette

    Measuring changes in substrate utilization in the myocardium in response to fasting using hyperpolarized [1-(13)C]butyrate and [1-(13)C]pyruvate.

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    Cardiac dysfunction is often associated with a shift in substrate preference for ATP production. Hyperpolarized (HP) (13)C magnetic resonance spectroscopy (MRS) has the unique ability to detect real-time metabolic changes in vivo due to its high sensitivity and specificity. Here a protocol using HP [1-(13)C]pyruvate and [1-(13)C]butyrate is used to measure carbohydrate versus fatty acid metabolism in vivo. Metabolic changes in fed and fasted Sprague Dawley rats (n = 36) were studied at 9.4 T after tail vein injections. Pyruvate and butyrate competed for acetyl-CoA production, as evidenced by significant changes in [(13)C]bicarbonate (-48%), [1-(13)C]acetylcarnitine (+113%), and [5-(13)C]glutamate (-63%), following fasting. Butyrate uptake was unaffected by fasting, as indicated by [1-(13)C]butyrylcarnitine. Mitochondrial pseudoketogenesis facilitated the labeling of the ketone bodies [1-(13)C]acetoacetate and [1-(13)C]β-hydroxybutyryate, without evidence of true ketogenesis. HP [1-(13)C]acetoacetate was increased in fasting (250%) but decreased during pyruvate co-injection (-82%). Combining HP (13)C technology and co-administration of separate imaging agents enables noninvasive and simultaneous monitoring of both fatty acid and carbohydrate oxidation. This protocol illustrates a novel method for assessing metabolic flux through different enzymatic pathways simultaneously and enables mechanistic studies of the changing myocardial energetics often associated with disease

    The phase transition in the localized ferromagnet EuO probed by muSR

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    We report results of muon spin rotation measurements performed on the ferromagnetic semiconductor EuO, which is one of the best approximations to a localized ferromagnet. We argue that implanted muons are sensitive to the internal field primarily through a combination of hyperfine and Lorentz fields. The temperature dependences of the internal field and the relaxation rate have been measured and are compared with previous theoretical predictions.Comment: 4 pages, 4 figure

    A fatal case of oxygen embolism in a hospital

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    This case reports on a 68-year-old man who was found dead in hospital next to his bed. Before this, he had been treated with intravenous antibiotics for pneumonia. The body was found with a peripheral venous catheter connected to a nasal cannula delivering oxygen (O2) from the wall. Extensive medico–legal examinations were performed, including post-mortem computed tomography (CT), complete conventional autopsy, histological and immunohistochemistry analysis, toxicological analysis and post-mortem chemistry. Additionally, CT-guided gas sampling was performed at multiple sites to collect samples for gas analysis. During the external examination, massive subcutaneous emphysema was visible over the entire surface of the body. The CT scan revealed the presence of gas throughout the vascular system, and in the subcutaneous and muscular tissues. The autopsy confirmed the presence of lobar pneumonia and multiple gas bubbles in the vascular system. The gas analysis results showed a subnormal concentration of oxygen, confirming the suspected pure O2 embolism. Moreover, the carbon dioxide (CO2) concentration in the gas sample from the heart was elevated to a level similar to those found in scuba diving fatalities. This could come from degassing of dissolved CO2 that accumulated and was trapped in the cardiac cavity. Based on the results of the different exams performed, and especially the gas analysis results, it was concluded that the cause of death was O2 embolism

    Assessment of Aspartate and Bicarbonate Produced From Hyperpolarized [1-13C]Pyruvate as Markers of Renal Gluconeogenesis.

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    As both a consumer and producer of glucose, the kidney plays a significant role in glucose homeostasis. Measuring renal gluconeogenesis requires invasive techniques, and less invasive methods would allow renal gluconeogenesis to be measured more routinely. Magnetic resonance spectroscopy and imaging of infused substrates bearing hyperpolarized carbon-13 spin labels allows metabolism to be detected within the body with excellent sensitivity. Conversion of hyperpolarized 1-13C pyruvate in the fasted rat liver is associated with gluconeogenic flux through phosphoenolpyruvate carboxykinase (PEPCK) rather than pyruvate dehydrogenase (PDH), and this study tested whether this was also the case in the kidney. The left kidney was scanned in fed and overnight-fasted rats either with or without prior treatment by the PEPCK inhibitor 3-mercaptopicolinic acid (3-MPA) following infusion of hyperpolarized 1-13C pyruvate. The 13C-bicarbonate signal normalized to the total metabolite signal was 3.2-fold lower in fasted rats (p = 0.00073) and was not significantly affected by 3-MPA treatment in either nutritional state. By contrast, the normalized [1-13C]aspartate signal was on average 2.2-fold higher in the fasted state (p = 0.038), and following 3-MPA treatment it was 2.8-fold lower in fed rats and 15-fold lower in fasted rats (p = 0.001). These results confirm that, unlike in the liver, most of the pyruvate-to-bicarbonate conversion in the fasted kidney results from PDH flux. The higher conversion to aspartate in fasted kidney and the marked drop following PEPCK inhibition demonstrate the potential of this metabolite as a marker of renal gluconeogenesis

    Dynamic Nuclear Polarization by Thermal Mixing Under Partial Saturation

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    We describe a low-temperature thermodynamic model for dynamic nuclear polarization (DNP) via continuous-wave partial saturation of electron spin resonance (ESR) lines that are both homogeneously and inhomogeneously broadened. It is a variant of a reasoning proposed by Borghini, which in turn used Redfield's thermodynamic treatment of saturation. Our variant is furthermore based on Provotorov's insight that under partial saturation of a coupled-spin system two distinct spin temperatures should appear in a thermodynamical theory. We apply our model to DNP results obtained at a temperature of 1.2K and in magnetic fields of 3.35 and 5T on 1-13C labeled sodium acetate dissolved in a frozen D2O/ethanol-d6 solution doped with the free radical TEMP

    Magnetic properties of pure and Gd doped EuO probed by NMR

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    An Eu NMR study in the ferromagnetic phase of pure and Gd doped EuO was performed. A complete description of the NMR lineshape of pure EuO allowed for the influence of doping EuO with Gd impurities to be highlighted. The presence of a temperature dependent static magnetic inhomogeneity in Gd doped EuO was demonstrated by studying the temperature dependence of the lineshapes. The results suggest that the inhomogeneity in 0.6% Gd doped EuO is linked to colossal magnetoresistance. The measurement of the spin-lattice relaxation times as a function of temperature led to the determination of the value of the exchange integral J as a function of Gd doping. It was found that J is temperature independent and spatially homogeneous for all the samples and that its value increases abruptly with increasing Gd doping.Comment: 14 pages, 10 figures, to be published in Physical Review
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