273 research outputs found

    Lowest-energy structures of 13-atom binary clusters: Do icosahedral clusters exist in binary liquid alloys?

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    Although the existence of 13-atom icosahedral clusters in one-component close-packed undercooled liquids was predicted more than half a century ago by Frank, the existence of such icosahedral clusters is less clear in liquid alloys. We study the lowest-energy structures of 13-atom AxB13-x Lennard-Jones binary clusters using the modified space-fixed genetic algorithm and the artificial Lennard-Jones potential designed by Kob and Andersen. Curiously, the lowest-energy structures are non-icosahedral for almost all compositions. The role played by the icosahedral cluster in a binary glass is questionable.Comment: 10 pages, 3 figure (conference paper of LAM12) to be published in J. Non-Crystalline Solid

    Low-Energy Electron-Track Imaging for a Liquid Argon Time-Projection-Chamber Telescope Concept using Probabilistic Deep Learning

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    The GammaTPC is an MeV-scale single-phase liquid argon time-projection-chamber gamma-ray telescope concept with a novel dual-scale pixel-based charge-readout system. It promises to enable a significant improvement in sensitivity to MeV-scale gamma-rays over previous telescopes. The novel pixel-based charge readout allows for imaging of the tracks of electrons scattered by Compton interactions of incident gamma-rays. The two primary contributors to the accuracy of a Compton telescope in reconstructing an incident gamma-ray's original direction are its energy and position resolution. In this work, we focus on using deep learning to optimize the reconstruction of the initial position and direction of electrons scattered in Compton interactions, including using probabilistic models to estimate predictive uncertainty. We show that the deep learning models are able to predict locations of Compton scatters of MeV-scale gamma-rays from simulated pixel-based data to better than 0.6 mm RMS error, and are sensitive to the initial direction of the scattered electron. We compare and contrast different deep learning uncertainty estimation algorithms for reconstruction applications. Additionally, we show that event-by-event estimates of the uncertainty of the locations of the Compton scatters can be used to select those events that were reconstructed most accurately, leading to improvement in locating the origin of gamma-ray sources on the sky

    Lessening the hazards of Florida red tides: a common sense approach

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hoagland, P., Kirkpatrick, B., Jin, D., Kirkpatrick, G., Fleming, L. E., Ullmann, S. G., Beet, A., Hitchcock, G., Harrison, K. K., Li, Z. C., Garrison, B., Diaz, R. E., & Lovko, V. Lessening the hazards of Florida red tides: a common sense approach. Frontiers in Marine Science, 7, (2020): 538, doi:10.3389/fmars.2020.00538.In the Gulf of Mexico, especially along the southwest Florida coast, blooms of the dinoflagellate Karenia brevis are a coastal natural hazard. The organism produces a potent class of toxins, known as brevetoxins, which are released following cell lysis into ocean or estuarine waters or, upon aerosolization, into the atmosphere. When exposed to sufficient levels of brevetoxins, humans may suffer from respiratory, gastrointestinal, or neurological illnesses. The hazard has been exacerbated by the geometric growth of human populations, including both residents and tourists, along Florida’s southwest coast. Impacts to marine organisms or ecosystems also may occur, such as fish kills or deaths of protected mammals, turtles, or birds. Since the occurrence of a severe Karenia brevis bloom off the southwest Florida coast three-quarters of a century ago, there has been an ongoing debate about the best way for humans to mitigate the impacts of this hazard. Because of the importance of tourism to coastal Florida, there are incentives for businesses and governments alike to obfuscate descriptions of these blooms, leading to the social amplification of risk. We argue that policies to improve the public’s ability to understand the physical attributes of blooms, specifically risk communication policies, are to be preferred over physical, chemical, or biological controls. In particular, we argue that responses to this type of hazard must emphasize maintaining the continuity of programs of scientific research, environmental monitoring, public education, and notification. We propose a common-sense approach to risk communication, comprising a simplification of the public provision of existing sources of information to be made available on a mobile website.The research leading to these results was supported by the US National Science Foundation (NSF) under NSF Grant No. CNH 1009106. PH and DJ acknowledge the complementary support under NSF Grant No. PFI/BIC 1534054

    Adult Out of Court Disposal Pilot Evaluation - Final Report

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    This report combines the findings from the process and impact evaluations of the Adult Out of Court Disposal (OOCD) pilot which aimed to: assess whether (a) the pilot achieved the requirements of greater simplicity and transparency, with (b) acceptable wider implications for Criminal Justice Partners (i.e., police, HMCTS, CPS, NOMS)

    The neurological effects of Florida Red Tide (FRT) blooms [poster]

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    Presented at the Eighth Symposium on Harmful Algae in the U.S. November 15 - 19, 2015, Long Beach, CaliforniaKarenia brevis is a marine dinoflagellate responsible for Florida red tide (FRT) blooms off the west coast of Florida. K. brevis contains brevetoxins, a neurotoxin that is absorbed by shellfish as well as released into the air. Brevetoxins are known to cause disruptions in normal neurological functions and are associated with neurotoxic shellfish poisoning (NSP). Previous research has emphasized the effect of FRT blooms on human health, from gastrointestinal to respiratory illnesses. However, there has been little research examining the effect of FRT blooms on neurological illnesses. There is research highlighting the biochemical effects of brevetoxins on mammalian nervous systems, so these symptoms can be matched to hospital codes that describe a hospital patient’s affliction. With these hospitalization codes, it is possible to study the relationship between FRT blooms and the occurrence of neurological illnesses in affected counties. The hospital data consists of inpatient data from 1988-2010 and emergency room data from 2005-2010. We will also use data containing K. brevis cells per liter as a measure of red tide occurrences.This research was sponsored by the National Science Foundation under NSF/CNH grant no. 100910

    Testing for the potential effects of Karenia brevis on school absences [poster]

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    Presented at the Eighth Symposium on Harmful Algae in the U.S. November 15 - 19, 2015, Long Beach, CaliforniaWe analyzed a potential relationship between changes in school absences in Sarasota County and Karenia brevis (Kb) count data. Brevetoxins released during Kb blooms could be a reason for students experiencing increased respiratory or gastrointestinal illnesses, causing an increase in absence rates. We designed a map to relate the locations of Sarasota County schools and the distributions of those Kb counts with a minimum of 10,000 cell counts per liter and above. Due to the proximity of Kb counts, we hypothesized that brevetoxins could have a greater effect on the schools near the coast of Florida rather than the schools inland. Because individuals could be affected by brevetoxins up to several days after being exposed, we expected to find a lagged effect of a bloom occurrence on school absences. Using a regression approach, we were unable to detect an association between Kb counts and student absences. In some cases, the direction of the effects were opposite to what would be expected (i.e., an increase in Kb counts was associated with a reduction in the percent absent rate). The results indicated that over 70% of the variation in the school percent absent rate could be explained by the latent characteristics of individual schools (such as variations in student populations across different schools), by school week, by month (such as the effects of flu outbreaks or and other seasonal factors), and by year

    CHANS : the characteristics of cost-effective policy responses for harmful algal blooms [poster]

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    Presented at CERF 2015: Grand Challenges in Coastal & Estuarine Science, Portland, Oregon, November 8 - 12, 2015 and at the Eighth Symposium on Harmful Algae in the U.S., Long Beach, California, November 15 – 19, 2015A growing concern for coastal management is the choice of appropriate public or private responses to HABs as a natural hazard. Considerable efforts have been devoted to understanding the scientific aspects of HABs, including their distributions in space and time, their ecological roles, and the nature of their toxic effects, among others. Much energy also has been directed at exploring socio-economic impacts and identifying potential management actions, including actions to prevent, control, or mitigate blooms. Using blooms of Florida red tide (Karenia brevis) as a case study, we develop an approach to the choice of policy responses to K. brevis blooms. Importantly, several new types of public health, environmental, and socio-economic impacts now are beginning to be revealed, including human gastrointestinal and potential neurological illnesses; morbidities and mortalities of protected species, including manatees, cetaceans, and sea turtles; increased numbers of hospital emergency room visits for the elderly; increased respiratory morbidities in workers, such as beach lifeguards; and potential reduced K- 12 school attendance. Optimal policy responses to this hazard are likely to depend critically upon why and where a bloom occurs, its spatial and temporal scales and toxicity, and the nature of its impacts. In the face of significant ongoing scientific uncertainties, and given estimates of impacts, we find that policies to expand and stabilize scientific research programs and environmental monitoring efforts, to develop and implement education programs for both residents and tourists, and to communicate the physical aspects of blooms to the public in a timely fashion are likely optimal.This research was sponsored by the National Science Foundation under NSF/CNH Grant No. 1009106

    CHANS : modeling the dynamics of HABs, human communities, and policy choices along the Florida Gulf Coast

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    Presented at the Eighth Symposium on Harmful Algae in the U.S., Long Beach, California, November 15 – 19, 2015Coupled human-nature systems (CHANS) involve dynamic interactions between humans and nature, often influenced by and affecting the distinct dynamic characteristics of each component. We present an overview of an ongoing interdisciplinary research program focused on a specific type of systems that couple expanding and fluctuating human coastal populations to episodic blooms of toxic marine algae, drawing examples primarily from human interactions with blooms of the toxic dinoflagellate Karenia brevis from the eastern Gulf of Mexico (“Florida red tides”). We introduce a set of HAB Symposium “speed” presentations and associated posters based on multi-disciplinary research. Using extant, but extraordinary, data to specify empirical models, this program of research has focused on characterizing the influence of anthropogenic sources on K. brevis blooms, assessing the public health and economic impacts of these blooms in an exposure-response framework, and defining the choice of appropriate human policy responses to the hazard. We present examples of the generic aspects of CHANS systems in the context of Florida red tides, and we discuss also some of the challenges involved in compiling and analyzing the relevant data to support our positive and normative analytical efforts.NSF/CNH NO.100910

    Descriptive epidemiology of selected birth defects, areas of Lombardy, Italy, 1999

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    <p>Abstract</p> <p>Background</p> <p>Birth defects are a leading cause of neonatal and infant mortality in Italy, however little is known of the etiology of most defects. Improvements in diagnosis have revealed increasing numbers of clinically insignificant defects, while improvements in treatment have increased the survival of those with more serious and complex defects. For etiological studies, prevention, and management, it is important to have population-based monitoring which provides reliable data on the prevalence at birth of such defects.</p> <p>Methods</p> <p>We recently initiated population-based birth defect monitoring in the Provinces of Mantova, Sondrio and Varese of the Region of Lombardy, northern Italy, and report data for the first year of operation (1999). The registry uses all-electronic source files (hospital discharge files, death certificates, regional health files, and pathology reports) and a proven case-generation methodology, which is described.</p> <p>The data were checked manually by consulting clinical records in hospitals. Completeness was checked against birth certificates by capture-recapture. Data on cases were coded according to the four-digit malformation codes of the International Classification of Diseases, Ninth Revision (ICD-9). We present data only on selected defects.</p> <p>Results</p> <p>We found 246 selected birth defects in 12,008 live births in 1999, 148 among boys and 98 among girls. Congenital heart defects (particularly septal defects) were the most common (90.8/10,000), followed by defects of the genitourinary tract (34.1/10, 000) (particularly hypospadias in boys), digestive system (23.3/10,000) and central nervous system (14.9/10,000), orofacial clefts (10.8/10,000) and Down syndrome (8.3/10,000). Completeness was satisfactory: analysis of birth certificates resulted in the addition of two birth defect cases to the registry.</p> <p>Conclusion</p> <p>This is the first population-based analysis on selected major birth defects in the Region. The high birth prevalences for septal heart defect and hypospadias are probably due to the inclusion of minor defects and lack of coding standardization; the latter problem also seems important for other defects. However the data produced are useful for estimating the demands made on the health system by babies with birth defects.</p

    Drug Design for CNS Diseases: Polypharmacological Profiling of Compounds Using Cheminformatic, 3D-QSAR and Virtual Screening Methodologies.

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    HIGHLIGHTS Many CNS targets are being explored for multi-target drug designNew databases and cheminformatic methods enable prediction of primary pharmaceutical target and off-targets of compoundsQSAR, virtual screening and docking methods increase the potential of rational drug design The diverse cerebral mechanisms implicated in Central Nervous System (CNS) diseases together with the heterogeneous and overlapping nature of phenotypes indicated that multitarget strategies may be appropriate for the improved treatment of complex brain diseases. Understanding how the neurotransmitter systems interact is also important in optimizing therapeutic strategies. Pharmacological intervention on one target will often influence another one, such as the well-established serotonin-dopamine interaction or the dopamine-glutamate interaction. It is now accepted that drug action can involve plural targets and that polypharmacological interaction with multiple targets, to address disease in more subtle and effective ways, is a key concept for development of novel drug candidates against complex CNS diseases. A multi-target therapeutic strategy for Alzheimer's disease resulted in the development of very effective Multi-Target Designed Ligands (MTDL) that act on both the cholinergic and monoaminergic systems, and also retard the progression of neurodegeneration by inhibiting amyloid aggregation. Many compounds already in databases have been investigated as ligands for multiple targets in drug-discovery programs. A probabilistic method, the Parzen-Rosenblatt Window approach, was used to build a "predictor" model using data collected from the ChEMBL database. The model can be used to predict both the primary pharmaceutical target and off-targets of a compound based on its structure. Several multi-target ligands were selected for further study, as compounds with possible additional beneficial pharmacological activities. Based on all these findings, it is concluded that multipotent ligands targeting AChE/MAO-A/MAO-B and also D1-R/D2-R/5-HT2A -R/H3-R are promising novel drug candidates with improved efficacy and beneficial neuroleptic and procognitive activities in treatment of Alzheimer's and related neurodegenerative diseases. Structural information for drug targets permits docking and virtual screening and exploration of the molecular determinants of binding, hence facilitating the design of multi-targeted drugs. The crystal structures and models of enzymes of the monoaminergic and cholinergic systems have been used to investigate the structural origins of target selectivity and to identify molecular determinants, in order to design MTDLs
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