42 research outputs found

    Two-stage Robust Optimization Approach for Enhanced Community Resilience Under Tornado Hazards

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    Catastrophic tornadoes cause severe damage and are a threat to human wellbeing, making it critical to determine mitigation strategies to reduce their impact. One such strategy, following recent research, is to retrofit existing structures. To this end, in this article we propose a model that considers a decision-maker (a government agency or a public-private consortium) who seeks to allocate resources to retrofit and recover wood-frame residential structures, to minimize the population dislocation due to an uncertain tornado. In the first stage the decision-maker selects the retrofitting strategies, and in the second stage the recovery decisions are made after observing the tornado. As tornado paths cannot be forecast reliably, we take a worst-case approach to uncertainty where paths are modeled as arbitrary line segments on the plane. Under the assumption that an area is affected if it is sufficiently close to the tornado path, the problem is framed as a two-stage robust optimization problem with a mixed-integer non-linear uncertainty set. We solve this problem by using a decomposition column-and-constraint generation algorithm that solves a two-level integer problem at each iteration. This problem, in turn, is solved by a decomposition branch-and-cut method that exploits the geometry of the uncertainty set. To illustrate the model's applicability, we present a case study based on Joplin, Missouri. Our results show that there can be up to 20 percent reductions in worst-case population dislocation by investing 15 million dollars in retrofitting and recovery; that our approach outperforms other retrofitting policies, and that the model is not over-conservative

    Models and Observations of Sunspot Penumbrae

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    The mysteries of sunspot penumbrae have been under an intense scrutiny for the past 10 years. During this time, some models have been proposed and refuted, while the surviving ones had to be modified, adapted and evolved to explain the ever-increasing array of observational constraints. In this contribution I will review two of the present models, emphasizing their contributions to this field, but also pinpointing some of their inadequacies to explain a number of recent observations at very high spatial resolution. To help explaining these new observations I propose some modifications to each of them. These modifications bring those two seemingly opposite models closer together into a general picture that agrees well with recent 3D magneto-hydrodynamic simulations.Comment: 9 pages, 1 color figure. Review talk to appear in the proceedings of the International Workshop of 2008 Solar Total Eclipse: Solar Magnetism, Corona and Space Weather--Chinese Space Solar Telescope Scienc

    Undergraduate Biology Education Research Gordon Research Conference: A Meeting Report

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    The 2019 Undergraduate Biology Education Research Gordon Research Conference (UBER GRC), titled “Achieving Widespread Improvement in Undergraduate Education,” brought together a diverse group of researchers and practitioners working to identify, promote, and understand widespread adoption of evidence-based teaching, learning, and success strategies in undergraduate biology. Graduate students and postdocs had the additional opportunity to present and discuss research during a Gordon Research Seminar (GRS) that preceded the GRC. This report provides a broad overview of the UBER GRC and GRS and highlights major themes that cut across invited talks, poster presentations, and informal discussions. Such themes include the importance of working in teams at multiple levels to achieve instructional improvement, the potential to use big data and analytics to inform instructional change, the need to customize change initiatives, and the importance of psychosocial supports in improving undergraduate student well-being and academic success. The report also discusses the future of the UBER GRC as an established meeting and describes aspects of the conference that make it unique, both in terms of facilitating dissemination of research and providing a welcoming environment for conferees

    Respuestas de oyentes y expertos musicales a una encuesta para valorar la percepción musical en salas de conciertos, auditorios y teatros

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    Para valorar la percepción musical en salas de concierto se diseñó una encuesta de 58 preguntas en la que cada una se valoraba de 0 a 5 puntos. A esta encuesta han respondido 1057 personas entre público en general y expertos musicales, sin formación especializada en acústica, tras la audición de un concierto en alguno de los 14 auditorios, salas de conciertos y teatros ubicados en diferentes comunidades de nuestro país (8 en el sur y 6 en levante). El análisis de las respuestas obtenidas ha mostrado que la fluctuación de la valoración media de cada una de las preguntas de la encuesta en una sala es un patrón que se repite aproximadamente en todas las salas estudiadas, formando una banda de aproximadamente 1 punto de variación en cada respuesta que contiene a todas las salas. Los límites de esta banda indicarían los extremos de respuesta subjetiva asociada a las salas de conciertos.Ponencia presentada en el Encuentro Ibérico de Acústica. EAA Symposium. Gandía(España). 2006.In order to evaluate the quality of the musical perception in concert halls, a survey with 58 items was designed in which each question was valued from 0 to 5 points. This survey has been replied by 1057 people between general public and musical experts without any specialized formation in acoustics, after the audition of a concert in any of the 14 auditoriums, concert hall or theatres, located in different regions of our country (8 in the south and 6 in the east). The analysis has shown that the fluctuation of the mean valuation of each question of the survey in a determined room is a pattern that is repeated approximately in all of the studied spaces, forming a band of approximately 1 variation point in each answer and that contains to all rooms. The limits of this band would indicate the ends of the subjective response associated to concert halls

    Elaboration process of a subjective response test from listeners and Musical experts, as a tool of evaluation of the musical perception in Concerts halls, auditoria and theatres

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    In order to tackle the study related to the requirements for musical audition in concert halls, some measurements and analyses of objective acoustic parameters have been made. However, the subjective evaluation of the sensation that the values of these acoustic parameters have on the listeners, can only be shown by means of a questionnaire that listeners have to answer. Such questionnaire has been formulated in an understandable way and the questions are directly or indirectly related to the abovementioned parameters. The aim of the present article is to present the elaboration process of a test of subjective response addressed to the general public and to some musical experts who have no special skills on acoustics. This study has been made in 13 auditoria, concert rooms and theatres distributed in different Autonomous Regions of Spain.Para abordar el estudio de las exigencias para la audición musical en salas de conciertos se realiza la medida y análisis de parámetros acústicos objetivos. Sin embargo, la valoración subjetiva de la sensación que unos u otros valores de esos parámetros acústicos producen en la audiencia, sólo puede ponerse de manifiesto a través de las respuestas de los oyentes a una encuesta cuyas preguntas, formuladas de manera comprensible, estén relacionadas, directa o indirectamente, con dichos parámetros acústicos. El objeto de este artículo es presentar el proceso de elaboración de un test de respuesta subjetiva dirigido al público en general y a expertos musicales pero sin formación especializada en acústica. Este estudio se ha realizado en 13 auditorios, salas de conciertos y teatros repartidos en diferentes Comunidades Autónomas de nuestro país. Ponencia presentada al Encuentro Ibérico de Acústica. EAA Symposium. Gandía (España). 200

    Marine Biodiversity in the Caribbean: Regional Estimates and Distribution Patterns

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    This paper provides an analysis of the distribution patterns of marine biodiversity and summarizes the major activities of the Census of Marine Life program in the Caribbean region. The coastal Caribbean region is a large marine ecosystem (LME) characterized by coral reefs, mangroves, and seagrasses, but including other environments, such as sandy beaches and rocky shores. These tropical ecosystems incorporate a high diversity of associated flora and fauna, and the nations that border the Caribbean collectively encompass a major global marine biodiversity hot spot. We analyze the state of knowledge of marine biodiversity based on the geographic distribution of georeferenced species records and regional taxonomic lists. A total of 12,046 marine species are reported in this paper for the Caribbean region. These include representatives from 31 animal phyla, two plant phyla, one group of Chromista, and three groups of Protoctista. Sampling effort has been greatest in shallow, nearshore waters, where there is relatively good coverage of species records; offshore and deep environments have been less studied. Additionally, we found that the currently accepted classification of marine ecoregions of the Caribbean did not apply for the benthic distributions of five relatively well known taxonomic groups. Coastal species richness tends to concentrate along the Antillean arc (Cuba to the southernmost Antilles) and the northern coast of South America (Venezuela – Colombia), while no pattern can be observed in the deep sea with the available data. Several factors make it impossible to determine the extent to which these distribution patterns accurately reflect the true situation for marine biodiversity in general: (1) highly localized concentrations of collecting effort and a lack of collecting in many areas and ecosystems, (2) high variability among collecting methods, (3) limited taxonomic expertise for many groups, and (4) differing levels of activity in the study of different taxa

    Clinical validation of cutoff target ranges in newborn screening of metabolic disorders by tandem mass spectrometry: a worldwide collaborative project.

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