318 research outputs found

    Advancing Health Behavior Research and Scholarship through Mentorship of First Generation, Underrepresented Undergraduate Students

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    This article provides perspectives about mentorship of undergraduate mentees from directors of formal, externally funded training programs within the context of one of the most ethnically diverse national universities. The authors reflect about their mentorship of first generation and underrepresented undergraduate students and offer recommendations for others training similar students

    Learning on a Budget Using Distributional RL

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    Agents acting in real-world scenarios often have constraints such as finite budgets or daily job performance targets. While repeated (episodic) tasks can be solved with existing RL algorithms, methods need to be extended if the repetition depends on performance. Recent work has introduced a distributional perspective on reinforcement learning, providing a model of episodic returns. Inspired by these results we contribute the new budget- and risk-aware distributional reinforcement learning (BRAD-RL) algorithm that bootstraps from the C51 distributional output and then uses value iteration to estimate the value of starting an episode with a certain amount of budget. With this strategy we can make budget-wise action selection within each episode and maximize the return across episodes. Experiments in a grid-world domain highlight the benefits of our algorithm, maximizing discounted future returns when low cumulative performance may terminate repetition

    A Survey of Learning in Multiagent Environments: Dealing with Non-Stationarity

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    The key challenge in multiagent learning is learning a best response to the behaviour of other agents, which may be non-stationary: if the other agents adapt their strategy as well, the learning target moves. Disparate streams of research have approached non-stationarity from several angles, which make a variety of implicit assumptions that make it hard to keep an overview of the state of the art and to validate the innovation and significance of new works. This survey presents a coherent overview of work that addresses opponent-induced non-stationarity with tools from game theory, reinforcement learning and multi-armed bandits. Further, we reflect on the principle approaches how algorithms model and cope with this non-stationarity, arriving at a new framework and five categories (in increasing order of sophistication): ignore, forget, respond to target models, learn models, and theory of mind. A wide range of state-of-the-art algorithms is classified into a taxonomy, using these categories and key characteristics of the environment (e.g., observability) and adaptation behaviour of the opponents (e.g., smooth, abrupt). To clarify even further we present illustrative variations of one domain, contrasting the strengths and limitations of each category. Finally, we discuss in which environments the different approaches yield most merit, and point to promising avenues of future research

    A Survey of Learning in Multiagent Environments: Dealing with Non-Stationarity

    Get PDF
    The key challenge in multiagent learning is learning a best response to the behaviour of other agents, which may be non-stationary: if the other agents adapt their strategy as well, the learning target moves. Disparate streams of research have approached non-stationarity from several angles, which make a variety of implicit assumptions that make it hard to keep an overview of the state of the art and to validate the innovation and significance of new works. This survey presents a coherent overview of work that addresses opponent-induced non-stationarity with tools from game theory, reinforcement learning and multi-armed bandits. Further, we reflect on the principle approaches how algorithms model and cope with this non-stationarity, arriving at a new framework and five categories (in increasing order of sophistication): ignore, forget, respond to target models, learn models, and theory of mind. A wide range of state-of-the-art algorithms is classified into a taxonomy, using these categories and key characteristics of the environment (e.g., observability) and adaptation behaviour of the opponents (e.g., smooth, abrupt). To clarify even further we present illustrative variations of one domain, contrasting the strengths and limitations of each category. Finally, we discuss in which environments the different approaches yield most merit, and point to promising avenues of future research

    Oceanographic processes and products around the Iberian margin: a new multidisciplinary approach

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    Our understanding of the role of bottom currents and associated oceanographic processes (e.g, overflows, barotropic tidal currents) including intermittent processes (e.g, vertical eddies, deep sea storms, horizontal vortices, internal waves and tsunamis) is rapidly evolving. Many deep-water processes remain poorly understood due to limited direct observations, but may generate significant depositional and erosional features on both short-and long-term time scales. This paper describes these oceanographic processes and examines their potential role in the sedimentary features around the Iberian margin. The paper explores the implications of the processes studied, given their secondary role relative to other factors such as mass-transport and turbiditic processes. An integrated interpretation of these oceanographic processes requires an understanding of contourites, sea-floor features, their spatial and temporal evolution, and the near-bottom flows that form them. Given their complex, three-dimensional and temporally-variable nature, integration of these processes into sedimentary, oceanographic and climatological frameworks will require a multidisciplinary approach that includes Geology, Physical Oceanography, Paleoceanography and Benthic Biology. This approach will synthesize oceanographic data, seafloor morphology, sediments and seismic images to improve our knowledge of permanent and intermittent processes around Iberia, and evaluate their conceptual and regional role in the sedimentary evolution of the margin. © 2015, Instituto Geologico y Minero de Espana. All rights reservedEl conocimiento del papel de las corrientes de fondo y los procesos oceanográficos asociados (overflows, corrientes de marea barotrópicas, etc), incluyendo procesos intermitentes (eddies, tormentas profundas, ondas internas, tsunamis, etc), está evolucionando rápidamente. Muchos de estos procesos son poco conocidos, en parte debido a que las observaciones directas son limitadas, si bien pueden generar importantes rasgos deposicionales y/o erosivos a escalas temporales de corto o largo periodo. Este artículo describe dichos procesos oceanográficos y examina su influencia en la presencia de rasgos sedimentarios alrededor del margen Ibérico. El trabajo discute las implicaciones de dichos procesos y el papel secundario que juegan en relación a otros factores tales como los procesos de transporte gravitacionales en masa y los turbidíticos. Para un mejor conocimiento de la sedimentación marina profunda, y en concreto de los sistemas contorníticos, se requiere de una interpretación de estos procesos oceanográficos, cuál es su evolución espacial y temporal, cómo afectan a las corrientes de fondo y cómo se ven afectados por la topografía submarina. Sin embargo, dada su complejidad y su variable naturaleza tridimensional y temporal, es necesario que estos procesos se integren en un marco sedimentológico, oceanográfico y climatológico con un enfoque multidisciplinar que incluyan la Geología, la Oceanografía Física, la Paleoceanografía y la Biología bentónica. Esta integración requiere de una mayor compilación de datos oceanográficos, de un mejor conocimiento de la morfología del fondo marino, y de una mejor caracterización de los sedimentos en ambientes profundos. Todo ello permitirá mejorar nuestro conocimiento de los procesos permanentes e intermitentes alrededor de Iberia y evaluar su verdadero efecto en la evolución sedimentaria delos márgenes continentales que le rodeanPostprint0,000

    Mapping sustainability initiatives in higher education institutions in Latin America

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    Many higher education institutions (HEIs) around the world are involved in a variety of sustainability initiatives. These are acknowledged to be important elements in fostering the cause of sustainability in HEIs, in further developing the organizations’ culture and in acting as enablers in the institutional embedding of sustainability. But despite the relevance of sustainability initiatives, there is a lack of systematic international efforts in how best to map them, especially in Latin America. On the basis of the need to address this gap, this paper reports on the results of an empirical study, aimed at analyzing the current status of sustainability initiatives among Latin American HEIs. Apart from a review of the latest literature, an international survey was performed to design a model using principal component analysis to identify the main descriptors of sustainability initiatives among Latin American HEIs and also the major drivers and challenges. The study sheds some light on the ways universities perceive and handle sustainability-related initiatives. The results show that sustainability is being incorporated in more than 80% of the sampled universities, and that a special emphasis is being given to campus operations. The value of the paper resides on the fact that it one of the few papers that have holistically investigated trends in sustainable development across universities in Latin America. The implications of the study are twofold. It maps for the first time how sustainable development initiatives are being practiced in 157 universities in 13 countries, being one of the most comprehensive studies of its kind, and it also outlines some of the main challenges that universities in the region face. The central message of this paper is that the different levels of emphasis given to SD in Latin American universities need to be better understood in order to catalyze continued and long-term actions

    Mutations in lectin complement pathway genes COLEC11 and MASP1 cause 3MC syndrome

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    Published version available at https://www.nature.com/articles/ng.757#Ack1This work was supported in part by grants from NEWLIFE (P.L.B., A.D.-F. and C.R.), the Wellcome Trust (P.L.B.), Dubai Harvard Foundation for Medical Research (F.S.A.), the University Hospital of Bordeaux (C.R.), the UK Medical Research Council (A.W.) and EU-FP7 (201804-EUCILIA) (V.H.-H., D.J. and D.P.S.O.). This research was supported by the National Institute for Health Research Biomedical Research Centre at Great Ormond Street Hospital for Children NHS Foundation Trust and University College London (P.L.B.). P.L.B. is a Wellcome Trust Senior Research Fellow

    Quantitative image analysis of polyhydroxyalkanoates inclusions from microbial mixed cultures under different SBR operation strategies

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    Polyhydroxyalkanoates (PHAs) produced from mixed microbial cultures (MMC), regarded as potential substitutes of petrochemical plastics, can be found as intracellular granules in various microorganisms under limited nutrient conditions and excess of carbon source. PHA is traditionally quantified by laborious and time-consuming chromatography analysis, and a simpler and faster method to assess PHA contents from MMC, such as quantitative image analysis (QIA), is of great interest. The main purpose of the present work was to upgrade a previously developed QIA methodology (Mesquita et al., 2013a, 2015) for MMC intracellular PHA contents quantification, increase the studied intracellular PHA concentration range and extend to different sequencing batch reactor (SBR) operation strategies. Therefore, the operation of a new aerobic dynamic feeding (ADF) SBR allowed further extending the studied operating conditions, dataset, and range of the MMC intracellular PHA contents from the previously reported anaerobic/aerobic cycle SBR. Nile Blue A (NBA) staining was employed for epifluorescence microscope visualization and image acquisition, further fed to a custom developed QIA. Data from each of the feast and famine cycles of both SBR were individually processed using chemometrics analysis, obtaining the correspondent partial least squares (PLS) models. The PHA concentrations determined from PLS models were further plotted against the results obtained in the standard chromatographic method. For both SBR the predicted ability was higher at the end of the feast stage than for the famine stage. Indeed, an independent feast and famine QIA data treatment was found to be fundamental to obtain the best prediction abilities. Furthermore, a promising overall correlation (R2 of 0.83) could be found combining the overall QIA data regarding the PHA prediction up to a concentration of 1785.1 mgL-1 (37.3 wt%). Thus, the results confirm that the presented QIA methodology can be seen as promising for estimating higher intracellular PHA concentrations for a larger reactors operation systems and further extending the prediction range of previous studies.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE01-0145-FEDER-000004) funded by European Regional Development Fundunder the scope ofNorte2020 - ProgramaOperacional Regional do Norte.The authors also acknowledge the financial support to Cristiano S. Leal (PTDC/EBB-EBI/103147/2008, FCOMP-01-0124-FEDER009704) and Daniela P. Mesquita through the FCT postdoctoral grant (SFRH/BPD/82558/2011).info:eu-repo/semantics/publishedVersio
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