128 research outputs found

    Information-theoretic measurements of coupling between structure and dynamics in glass-formers

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    We analyse the connections between structure and dynamics in two model glass-formers, using the mutual information between an initial configuration and the ensuing dynamics to compare the predictive value of different structural observables. We consider the predictive power of normal modes, locally favoured structures, and coarse-grained measurements of local energy and density. The mutual information allows the influence of the liquid structure on the dynamics to be analysed quantitatively as a function of time, showing that normal modes give the most useful predictions on short time scales while local energy and density are most strongly predictive at long times.Comment: 10 pages, 7 fig

    Single-enzyme biomineralization of cadmium sulfide nanocrystals with controlled optical properties

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    Nature has evolved several unique biomineralization strategies to direct the synthesis and growth of inorganic materials. These natural systems are complex, involving the interaction of multiple biomolecules to catalyze biomineralization and template growth. Herein we describe the first report to our knowledge of a single enzyme capable of both catalyzing mineralization in otherwise unreactive solution and of templating nanocrystal growth. A recombinant putative cystathionine γ-lyase (smCSE) mineralizes CdS from an aqueous cadmium acetate solution via reactive H2S generation from l-cysteine and controls nanocrystal growth within the quantum confined size range. The role of enzymatic nanocrystal templating is demonstrated by substituting reactive Na2S as the sulfur source. Whereas bulk CdS is formed in the absence of the enzyme or other capping agents, nanocrystal formation is observed when smCSE is present to control the growth. This dual-function, single-enzyme, aerobic, and aqueous route to functional material synthesis demonstrates the powerful potential of engineered functional material biomineralization

    Electroencephalographic and behavioral convulsant effects of hydrobromide and hydrochloride salts of bupropion in conscious rodents

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    A novel bromide salt of the antidepressant bupropion (bupropion HBr) has recently been developed and approved for use in the United States. Given previous use of bromides to treat seizures, and that the existing chloride salt of bupropion (HCl) can cause seizures, it is important to determine if the HBr salt may be less likely to cause seizures than the HCl salt. In the present animal studies this was evaluated by means of quantified electroencephalogram (EEG), observation, and the rotarod test in mice and rats. Both bupropion salts were tested at increasing equimolar doses administered intraperitoneally. The results in mice showed that bupropion HCl 125 mg/kg induced a significantly higher ten-fold increase in the mean number of cortical EEG seizures compared to bupropion HBr (7.50 ± 2.56 vs 0.75 ± 0.96; p = 0.045), but neither drug caused any brain injuries. In rats bupropion HBr 100 mg/kg induced single EEG seizure activity in the cortical and hippocampal (depth) electrodes and in significantly (p < 0.05) fewer rats (44%) compared to bupropion HCl, which induced 1 to 4 convulsions per rat in all rats (100%) dosed. The total duration of cortical seizures in bupropion HCl-treated rats was significantly longer than the corresponding values obtained in bupropion HBr-treated rats (424.6 seconds vs 124.5 seconds respectively, p < 0.05). Bupropion HCl consistently induced more severe convulsions at each dose level compared to bupropion HBr. Both treatments demonstrated a similar dose-dependent impairment of rotarod performance in mice. In conclusion, these findings suggest that bupropion HBr may have a significantly lower potential to induce seizures in mice and rats, particularly at higher doses, compared to bupropion HCl. Determination of this potential clinical advantage will require human studies. If confirmed by such studies, it is likely that this potential beneficial clinical benefit would be due to the presence of the bromide salt given the long history of the use of bromide to treat seizure disorders

    Work and Welfare in the American States: Analyzing the Effects of the JOBS Program

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    This research seeks to determine whether the Job Opportunities and Basic Skills GOBS) program (established under the 1988 Family Support Act) was successful in reducing the number of welfare recipients among U.S. states for the period 1984 to 1996. Within the context of two theoretical perspectives-developmental and rational choice-we assess the impact of JOBS on AFDC participation rates using a pooled time-series design. At best, JOBS had a minimal effect. We estimate that states with higher proportions of their AFDC populations enrolled in JOBS programs had only slightly lower rates of participation in AFDC. Other forces were far more influential in reducing welfare participation. In particular, states with higher per capita income, lower female unemployment rates, lower poverty rates, and higher wages for low-paying jobs had the lowest welfare recipiency The AFDC participation rates of neighboring states had a significant effect, as well. The analysis showed that more generous AFDC benefits exerted strong upward pressure on a state's welfare rolls.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    In the Round: The Future of Food

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    In collaboration with PopTech, the Center for Complexity (CfC) hosted a two day convening in March 2019 to discuss the future of food, conducted in-the-round. Conversations-in-the-round offer an experimental and collaborative forum where a variety of perspectives collide to reimagine how we should approach navigating complex challenges. 30 professionals, community leaders, ag-tech startups, policymakers, local activists, global aid administrators, and many other important voices in the food industry were in attendance. We did not set out to create solutions, rather we devoted our time to exploration — a process that allowed us to assess, discover, reality-check, and strategically plan the next phase of the journey. A publication was created to capture the discussions, workshops, proposals, deign principles and actionable next steps. The outcomes of this first convening will guide what comes next. Our aim is to initiate a series of projects conducted by the CfC and our partners to advance the future of food according to shared design principles. We are working with PopTech to host further convenings.https://digitalcommons.risd.edu/cfc_projectsprograms_globalsecurity_futureoffood/1000/thumbnail.jp

    Justify your alpha

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    Benjamin et al. proposed changing the conventional “statistical significance” threshold (i.e.,the alpha level) from p ≤ .05 to p ≤ .005 for all novel claims with relatively low prior odds. They provided two arguments for why lowering the significance threshold would “immediately improve the reproducibility of scientific research.” First, a p-value near .05provides weak evidence for the alternative hypothesis. Second, under certain assumptions, an alpha of .05 leads to high false positive report probabilities (FPRP2 ; the probability that a significant finding is a false positive

    Sistemas nacionais de inteligência: origens, lógica de expansão e configuração atual

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    A global experiment on motivating social distancing during the COVID-19 pandemic

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    Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges
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