Diffusion Of Responsibility And Level Of Risk Taking In Groups 1

This study reports evidence supporting the following propositions: (1) Group discussion and consensus concerning decisions that involve actual risk ana payoffs lead to greater risk taking than occurs in the absence of such discussion and consensus. (2) The mechanism that underlies this group‐induced shift toward greater risk taking consists of a diffusion or spreading of responsibility. Using risks and payoffs based on monetary gain and loss for problem‐solving performance, the above propositions received strong confirmation for male college subjects. The results of various experimental manipulations provided positive support for viewing diffusion of responsibility as the causal factor at work.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108279/1/ets200956.pd

Group Influence On Individual Risk Taking 1

Does group interaction lead to greater conservatism or to greater risk taking in decisions than would obtain were the decisions arrived at individually.–or is there an averaging effect? This question was investigated with a procedure in which the protagonist in each of 12 everyday life situations must choose between two courses of action, one of which involves considerably more risk than the other but also is much more rewarding if successful. The S must decide on the lowest level of probability for the success of the risky alternative that he would deem sufficient to warrant its choice. A total of 218 liberal arts university students participated in the study. In the experimental condition, the S s first arrived at individual decisions concerning each of the 12 situations; then, they were brought together in discussion groups of six with the request that they reach a group consensus on each decision; and afterward, they were asked to make all their decisions privately once again. Some S s also made private decisions yet another time two to six weeks later. The group members' judgments of one another's relative degrees of influence and of popularity within the group also were obtained. There were 14 all‐male and 14 all‐female groups. In the control condition, S s made their decisions individually each of two times with one week intervening, under instructions the second time that encouraged them to change rather than simply to recall their earlier decisions. It was found that (1) group decisions exhibit greater risk taking than appears in pre‐discussion individual decisions; (2) post‐discussion private decisions exhibit the same increase in risk taking as occurs in the group decisions; (3) the increase in risk taking resulting from the discussion process is still maintained after a subsequent period of two to six weeks has elapsed; (4) no shift in risk taking level occurs over time in the absence of the discussion process; and (5) degree of risk taking in pre‐discussion individual decisions and degree of judged influence within the group are positively related. Two interpretations of these findings were suggested, either or both of which may apply: (1) the knowledge that one's decisions are being made jointly with others leads to a diffusion of personal responsiblity, the outcome of which is an increased willingness to take risks; (2) high risk takers are more likely to take the initiative in social situations, with the result that they become more influential in the group.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108371/1/ets200112.pd

Oocyst wall formation and composition in coccidian parasites

The oocyst wall of coccidian parasites is a robust structure that is resistant to a variety of environmental and chemical insults. This resilience allows oocysts to survive for long periods, facilitating transmission from host to host. The wall is bilayered and is formed by the sequential release of the contents of two specialized organelles - wall forming body 1 and wall forming body 2 - found in the macrogametocyte stage of Coccidia. The oocyst wall is over 90% protein but few of these proteins have been studied. One group is cysteine-rich and may be presumed to crosslink via disulphide bridges, though this is yet to be investigated. Another group of wall proteins is rich in tyrosine. These proteins, which range in size from 8-31 kDa, are derived from larger precursors of 56 and 82 kDa found in the wall forming bodies. Proteases may catalyze processing of the precursors into tyrosine-rich peptides, which are then oxidatively crosslinked in a reaction catalyzed by peroxidases. In support of this hypothesis, the oocyst wall has high levels of dityrosine bonds. These dityrosine crosslinked proteins may provide a structural matrix for assembly of the oocyst wall and contribute to its resilience

Pharmacological characterizations of the 'legal high' fluorolintane and isomers

1,2-Diarylethylamines represent a class of molecules that have shown potential in pain, epilepsy, neurodegenerative disease and depression. Examples include lefetamine, remacemide, and lanicemine. Recently, several 1,2-diarylethylamines including the dissociatives diphenidine, methoxphenidine and ephenidine as well as the opioid MT-45, have appeared as ‘research chemicals’ or ‘legal highs’. Due to their rapid emergence little is known about their pharmacology. One of these, 1-[1-(2-fluorophenyl)-2-phenylethyl]pyrrolidine (fluorolintane, 2-F-DPPy), is available for purchase with purported dissociative effects meant to mimic phencyclidine (PCP) and ketamine. To better understand this emerging class, pharmacological investigations were undertaken for the first time on fluorolintane and its five aryl-fluorine-substituted isomers. In vitro binding studies revealed high N-methyl-D-aspartate (NMDA) receptor affinity (Ki = 87.92 nM) and off-target affinities at several sites including norepinephrine (NET), serotonin (SERT) and dopamine (DAT) transporters, and sigma receptors. High affinities for DAT were observed, which were typically greater than NMDA receptor affinities. Additional functional and behavioral experiments show fluorolintane inhibited NMDA receptor-induced field excitatory postsynaptic potentials in rat hippocampal slices and inhibited long-term potentiation induced by theta-burst stimulation in rat hippocampal slices with potencies consistent with its NMDA receptor antagonism. Finally fluorolintane significantly inhibited prepulse inhibition in rats, a measure of sensorimotor gating, with a median effective dose (ED50) of 13.3 mg/kg. These findings are consistent with anecdotal reports of dissociative effects of fluorolintane in humans

Bigtable: A Distributed Storage System for Structured Data

BigTable是一个分布式存储系统，它可以支持扩展到很大尺寸的数据：PB级别的数据，包含几千个商业服务器。Google的许多项目都存储在BigTable中，包括WEB索引、Google Earth 和Google Finance。这些应用对BigTable提出了截然不同的需求，无论是从数据量（从URL到网页到卫星图像）而言，还是从延迟需求（从后端批量处理到实时数据服务）而言。尽管这些不同的需求，BigTable已经为所有的Google产品提供了一个灵活的、高性能的解决方案。本文中，我们描述了BigTable提供的简单数据模型，它允许客户端对数据部署和格式进行动态控制，我们描述了BigTable的设计和实施

The moving minimum audible angle is smaller during self motion than during source motion

We are rarely perfectly still: our heads rotate in three axes and move in three dimensions, constantly varying the spectral and binaural cues at the ear drums. In spite of this motion, static sound sources in the world are typically perceived as stable objects. This argues that the auditory system-in a manner not unlike the vestibulo-ocular reflex-works to compensate for self motion and stabilize our sensory representation of the world. We tested a prediction arising from this postulate: that self motion should be processed more accurately than source motion. We used an infrared motion tracking system to measure head angle, and real-time interpolation of head related impulse responses to create "head-stabilized" signals that appeared to remain fixed in space as the head turned. After being presented with pairs of simultaneous signals consisting of a man and a woman speaking a snippet of speech, normal and hearing impaired listeners were asked to report whether the female voice was to the left or the right of the male voice. In this way we measured the moving minimum audible angle (MMAA). This measurement was made while listeners were asked to turn their heads back and forth between ± 15° and the signals were stabilized in space. After this "self-motion" condition we measured MMAA in a second "source-motion" condition when listeners remained still and the virtual locations of the signals were moved using the trajectories from the first condition. For both normal and hearing impaired listeners, we found that the MMAA for signals moving relative to the head was ~1-2° smaller when the movement was the result of self motion than when it was the result of source motion, even though the motion with respect to the head was identical. These results as well as the results of past experiments suggest that spatial processing involves an ongoing and highly accurate comparison of spatial acoustic cues with self-motion cues

Incidence of Resident Mistreatment in the Learning Environment Across Three Institutions

Introduction: Mistreatment in the learning environment is associated with negative outcomes for trainees. While the Association of American Medical Colleges (AAMC) annual Graduation Questionnaire (GQ) has collected medical student reports of mistreatment for a decade, there is not a similar nationally benchmarked survey for residents. The objective of this study is to explore the prevalence of resident experiences with mistreatment. Methods: Residents at three academic institutions were surveyed using questions similar to the GQ in 2018. Quantitative data were analyzed based on frequency and Mann-Whitney U tests to detect gender differences. Results: Nine hundred ninety-six of 2682 residents (37.1%) responded to the survey. Thirty-nine percent of residents reported experiencing at least one incident of mistreatment. The highest reported incidents were public humiliation (23.7%) and subject to offensive sexist remarks/comments (16.0%). Female residents indicated experiencing significantly more incidents of: public embarrassment, public humiliation, offensive sexist remarks, lower evaluations based on gender, denied opportunities for training or rewards, and unwanted sexual advances. Faculty were the most frequent instigators of mistreatment (66.4%). Of trainees who reported experiencing mistreatment, less than one-quarter reported the behavior. Conclusion: Mistreatment in the academic learning environment is a concern in residency programs. There is increased frequency among female residents

Saving the world’s terrestrial megafauna

From the late Pleistocene to the Holocene, and now the so called Anthropocene, humans have been driving an ongoing series of species declines and extinctions (Dirzo et al. 2014). Large-bodied mammals are typically at a higher risk of extinction than smaller ones (Cardillo et al. 2005). However, in some circumstances terrestrial megafauna populations have been able to recover some of their lost numbers due to strong conservation and political commitment, and human cultural changes (Chapron et al. 2014). Indeed many would be in considerably worse predicaments in the absence of conservation action (Hoffmann et al. 2015). Nevertheless, most mammalian megafauna face dramatic range contractions and population declines. In fact, 59% of the world’s largest carnivores (≥ 15 kg, n = 27) and 60% of the world’s largest herbivores (≥ 100 kg, n = 74) are classified as threatened with extinction on the International Union for the Conservation of Nature (IUCN) Red List (supplemental table S1 and S2). This situation is particularly dire in sub-Saharan Africa and Southeast Asia, home to the greatest diversity of extant megafauna (figure 1). Species at risk of extinction include some of the world’s most iconic animals—such as gorillas, rhinos, and big cats (figure 2 top row)—and, unfortunately, they are vanishing just as science is discovering their essential ecological roles (Estes et al. 2011). Here, our objectives are to raise awareness of how these megafauna are imperiled (species in supplemental table S1 and S2) and to stimulate broad interest in developing specific recommendations and concerted action to conserve them

Reciprocal regulation of carbon monoxide metabolism and the circadian clock

Circadian clocks are cell-autonomous oscillators regulating daily rhythms in a wide range of physiological, metabolic and behavioral processes. Feedback of metabolic signals, such as redox state, NAD+/NADH and AMP/ADP ratios, or heme, modulate circadian rhythms and thereby optimize energy utilization across the 24-h cycle. We show that rhythmic heme degradation, which generates the signaling molecule carbon monoxide (CO), is required for normal circadian rhythms as well as circadian metabolic outputs. CO suppresses circadian transcription by attenuating CLOCK– BMAL1 binding to target promoters. Pharmacological inhibition or genetic depletion of CO-producing heme oxygenases abrogates normal daily cycles in mammalian cells and Drosophila. In mouse hepatocytes, suppression of CO production leads to a global upregulation of CLOCK–BMAL1-dependent circadian gene expression and dysregulated glucose metabolism. Together, our findings show that CO metabolism is an important link between the basic circadian-clock machinery, metabolism and behavior