THE ANTHROPOLOGY OF ONLINE COMMUNITIES Wilson, Samuel M; Peterson, Leighton C
Annual review of anthropology,
01/2002, Letnik:
31, Številka:
1
Journal Article
Recenzirano
Information and communication technologies based on the Internet have
enabled the emergence of new sorts of communities and communicative
practices-phenomena worthy of the attention of ...anthropological
researchers. Despite early assessments of the revolutionary nature of the
Internet and the enormous transformations it would bring about, the changes
have been less dramatic and more embedded in existing practices and power
relations of everyday life. This review explores researchers' questions,
approaches, and insights within anthropology and some relevant related fields,
and it seeks to identify promising new directions for study. The general
conclusion is that the technologies comprising the Internet, and all the text
and media that exist within it, are in themselves cultural products.
Anthropology is thus well suited to the further investigation of these new, and
not so new, phenomena.
BaSnO3 has recently been identified as a high mobility wide gap semiconductor with significant potential for room temperature oxide electronics. Here, a detailed study of the high pressure oxygen ...sputter-deposition, microstructure, morphology, and stoichiometry of epitaxial BaSnO3 on SrTiO3(001) and MgO(001) is reported, optimized conditions resulting in single-phase, relaxed, close to stoichiometric films. Most significantly, vacuum annealing is established as a facile route to n-doped BaSnO3−δ, leading to electron densities above 1019 cm−3, 5 mΩ cm resistivities, and room temperature mobility of 20 cm2 V−1 s−1 in 300-Å-thick films on MgO(001). Mobility limiting factors, and the substantial scope for their improvement, are discussed.
•des-Tyr-dynorphin (DYN-A2−17) is a non-opioid dynorphin peptide.•Whether DYN-A2−17 has a role in energy balance is unknown.•DYN-A2−17 injected into PVN increases food intake and locomotor ...activity.•Co-injection of orexin-A and DYN-A2−17 increased food intake further compared to each peptide alone.•This study shows a novel function of DYN-A2−17 in regulating behaviors related to energy balance.
Food intake and physical activity are regulated by multiple neuropeptides, including orexin and dynorphin (DYN). Orexin-A (OXA) is one of two orexin peptides with robust roles in regulation of food intake and spontaneous physical activity (SPA). DYN collectively refers to several peptides, some of which act through opioid receptors (opioid DYN) and some whose biological effects are not mediated by opioid receptors (non-opioid DYN). While opioid DYN is known to increase food intake, the effects of non-opioid DYN peptides on food intake and SPA are unknown. Neurons that co-express and release OXA and DYN are located within the lateral hypothalamus. Limited evidence suggests that OXA and opioid DYN peptides can interact to modulate some aspects of behaviors classically related to orexin peptide function. The paraventricular hypothalamic nucleus (PVN) is a brain area where OXA and DYN peptides might interact to modulate food intake and SPA. We demonstrate that injection of des-Tyr-dynorphin (DYN-A2−17, a non opioid DYN peptide) into the PVN increases food intake and SPA in adult mice. Co-injection of DYN-A2−17 and OXA in the PVN further increases food intake compared to DYN-A2−17 or OXA alone. This is the first report describing the effects of non-opioid DYN-A2−17 on food intake and SPA, and suggests that DYN-A2−17 interacts with OXA in the PVN to modulate food intake. Our data suggest a novel function for non-opioid DYN-A2−17 on food intake, supporting the concept that some behavioral effects of the orexin neurons result from combined actions of the orexin and DYN peptides.
The Maxwell relation, the Clausius-Clapeyron equation, and a non-iterative method to obtain the critical exponents have been used to characterize the magnetocaloric effect (MCE) and the nature of the ...phase transitions in Pr0.5Sr0.5MnO3, which undergoes a second-order paramagnetic to ferromagnetic (PM-FM) transition at , and a first-order ferromagnetic to antiferromagnetic (FM-AFM) transition at . We find that around the second-order PM-FM transition, the MCE (as represented by the magnetic entropy change, ΔSM) can be precisely determined from magnetization measurements using the Maxwell relation. However, around the first-order FM-AFM transition, values of ΔSM calculated with the Maxwell relation deviate significantly from those calculated by the Clausius-Clapeyron equation at the magnetic field and temperature ranges where a conversion between the AFM and FM phases occurs. A detailed analysis of the critical exponents of the second-order PM-FM transition allows us to correlate the short-range type magnetic interactions with the MCE. Using the Arrott-Noakes equation of state with the appropriate values of the critical exponents, the eld- and temperature-dependent magnetization curves, and hence the curves, have been simulated and compared with experimental data. A good agreement between the experimental and simulated data has been found in the vicinity of the Curie temperature TC, but a noticeable discrepancy is present for . This discrepancy arises mainly from the coexistence of AFM and FM phases and the presence of ferromagnetic clusters in the AFM matrix.
Nonlocal spin valves (NLSVs) generate pure spin currents, providing unique insight into spin injection and relaxation at the nanoscale. Recently it was shown that the puzzling low temperature ...nonmonotonicity of the spin accumulation in all-metal NLSVs occurs due to a manifestation of the Kondo effect arising from dilute local-moment-forming impurities in the nonmagnetic material. Here it is demonstrated that precise control over interdiffusion in Fe/Cu NLSVs via thermal annealing can induce dramatic increases in this Kondo suppression of injection efficiency, observation of injector/detector separation-dependent Kondo effects in both charge and spin channels simultaneously, and, in the limit of large interdiffusion, complete breakdown of standard Valet-Fert-based models. The Kondo effect in the charge channel enables extraction of the exact interdiffusion profile, quantifying the influence of local moment density on the injection efficiency and presenting a well-posed challenge to theory.
Stimulated by experimental advances in electrolyte gating methods, we investigate theoretically percolation in thin films of inhomogeneous complex oxides, such as La_{1-x}Sr_{x}CoO_{3} (LSCO), ...induced by a combination of bulk chemical and surface electrostatic doping. Using numerical and analytical methods, we identify two mechanisms that describe how bulk dopants reduce the amount of electrostatic surface charge required to reach percolation: (i) bulk-assisted surface percolation and (ii) surface-assisted bulk percolation. We show that the critical surface charge strongly depends on the film thickness when the film is close to the chemical percolation threshold. In particular, thin films can be driven across the percolation transition by modest surface charge densities. If percolation is associated with the onset of ferromagnetism, as in LSCO, we further demonstrate that the presence of critical magnetic clusters extending from the film surface into the bulk results in considerable enhancement of the saturation magnetization, with pronounced experimental consequences. These results should significantly guide experimental work seeking to verify gate-induced percolation transitions in such materials.
Abstract
Routine surveying of academic centers focused on the human-animal bond is critical to understand the trajectory of the field and to create an environment where centers can learn from one ...another and build collaborations. The purpose of this manuscript was to report the findings of a survey of these human-animal bond centers, to summarize the status of the field, and to identify changes within the field since 2016. Survey questions concentrated on the demographic characteristics, engagement programs, educational opportunities, and research focuses of the centers. Findings suggest that the field continues to grow as one-third of human-animal bond centers are less than 10 years old. The number of centers that participated in this survey increased by 31% compared with the previous survey. Centers have developed a variety of engagement programs, including animal-assisted intervention and companion animal education programs. About half of the centers (48%) offer degree programs and about one quarter of the centers (24%) offer certificate programs. Most centers (95%) focus their research on companion animals with the most studied companion animal being dogs (95%). The most frequent data collection method was surveys (86%). Qualitative analyses, behavior measures, and physiological measures were also common. The most notable changes from the 2016 survey include overall growth of the field (indicated by the establishment of new centers) and a shift in the specialty area of directors, moving from 44% of directors being veterinarians in 2016 survey to 90% having a human-focused specialty in the 2021 survey. Most centers’ research focused on animal-assisted interventions that are consistent with the previous survey. As the field of the human-animal bond continues to grow and more centers emerge, ongoing evaluation of offerings is important to track changes, identify needs, and foster success.
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