5,726 research outputs found
Estudio del deterioro de bienes patrimoniales: la mesa de giro de locomotoras de la estación Meridiano V de La Plata
El 27 de abril de 1910 se inauguraron los trabajos en la Estación cabecera del Ferrocarril Provincial La Plata al Meridiano V y los primeros 100 km de la vía férrea proyectada. A 200 metros de la estación de pasajeros ubicada en 17 y 71, se halla la mesa de giro de locomotoras cuyas dos pasarelas se construyeron con listones de madera de quebracho colorado de 120 x 14 x 3,5 cm cada uno. Actualmente esta estructura de importancia patrimonial se encuentra en avanzado estado de deterioro ocasionado por factores ambientales y biológicos. Para evaluar la funcionalidad estructural de la pasarela de madera, se extrajeron 4 listones con diferentes tipos de ataque; para diferenciarlos, las maderas se observaron bajo lupa estereoscópica.
Posteriormente se efectuaron tomografías axiales computadas para observar la profundidad y expansión del deterioro, realizándose ensayos mecánicos para evaluar el grado de resistencia del material afectado. Las maderas con mayor compromiso mecánico fueron aquellas más afectadas por hongos que causan el tipo de pudrición blanca, estos organismos atacan la lignina que es el componente responsable de la resistencia mecánica de las maderas duras.Tópico 4: Materiales. Evaluación de propiedades, caracterización tecnológica y patologías. Mamposterías (de ladrillos o piedras) y Morteros (materiales cálcicos y cementícios)
UNA APROXIMACIÓN A LA INFORMACIÓN SOBRE GOBIERNO CORPORATIVO (EL CASO DEL GOBIERNO ARGENTINO DE LAS EMPRESAS DE ALIMENTOS)
El trabajo efectúa una aproximación a algunas problemáticas vinculadas con el gobierno corporativo de las organizaciones a través de una perspectiva que incorpora el abordaje multidisciplinario: en particular a partir de la inclusión del concepto de la sostenibilidad y de la consideración de los múltiples usuarios involucrados (stakeholders). El gobierno corporativo de las organizaciones es analizado a partir de su situación actual, la cual involucra cuestiones normativas -en particular se consideran las de carácter contable- y considerando la información que dichas organizaciones proporcionan al respecto. Asimismo se incluyen los antecedentes en Argentina sobre el tema, en donde observamos que la realidad de nuestro mercado se acerca más a un modelo de control por la dirección, en particular por un desprendimiento de empresas familiares que a un sistema de eficiencia de mercado. Consideramos que los principios y recomendaciones propuestos por la Comisión Nacional de Valores favorecen el enfoque de sostenibilidad mediante el principio VI, Mantener un vínculo directo y responsable con la comunidad. Si bien existe información de mayor transparencia, las empresas del sector alimentos aún tienen un camino por avanzar en materia de sustentabilidad y rendición de cuentas debido a su compromiso con la seguridad alimentaria
Power in a Pandemic: Teachers’ Unions and Their Responses to School Reopening
Drawing on Bachrach and Baratz’s first and second faces of interest group power, we explore the relationship between teachers’ union power and reopening decisions during the fall 2020 semester in 250 large districts around the United States. We leverage a self-collected panel data set of reopening decisions coupled with measures of teachers’ union first face power (drawn from social media postings on teachers’ unions’ Facebook pages) and second face power (operationalized as district size, whether the school district negotiates a collective bargaining agreement with the teachers’ union, the length of the collective bargaining agreement, and the amount of revenue raised by the union). We found that school districts where teachers’ unions exhibit strong second face power (but not first face power) were less likely to start the school year with in-person instruction, were less likely to ever open during fall semester with in-person instruction and spent fewer weeks in in-person learning
Fourier Neural Operators for Arbitrary Resolution Climate Data Downscaling
Climate simulations are essential in guiding our understanding of climate
change and responding to its effects. However, it is computationally expensive
to resolve complex climate processes at high spatial resolution. As one way to
speed up climate simulations, neural networks have been used to downscale
climate variables from fast-running low-resolution simulations, but
high-resolution training data are often unobtainable or scarce, greatly
limiting accuracy. In this work, we propose a downscaling method based on the
Fourier neural operator. It trains with data of a small upsampling factor and
then can zero-shot downscale its input to arbitrary unseen high resolution.
Evaluated both on ERA5 climate model data and on the Navier-Stokes equation
solution data, our downscaling model significantly outperforms state-of-the-art
convolutional and generative adversarial downscaling models, both in standard
single-resolution downscaling and in zero-shot generalization to higher
upsampling factors. Furthermore, we show that our method also outperforms
state-of-the-art data-driven partial differential equation solvers on
Navier-Stokes equations. Overall, our work bridges the gap between simulation
of a physical process and interpolation of low-resolution output, showing that
it is possible to combine both approaches and significantly improve upon each
other.Comment: Presented at the ICLR 2023 workshop on "Tackling Climate Change with
Machine Learning
Economic Analyses of Respiratory Tract Infection Diagnostics:A Systematic Review
BACKGROUND: Diagnostic testing for respiratory tract infections is a tool to manage the current COVID-19 pandemic, as well as the rising incidence of antimicrobial resistance. At the same time, new European regulations for market entry of in vitro diagnostics, in the form of the in vitro diagnostic regulation, may lead to more clinical evidence supporting health-economic analyses. OBJECTIVE: The objective of this systematic review was to review the methods used in economic evaluations of applied diagnostic techniques, for all patients seeking care for infectious diseases of the respiratory tract (such as pneumonia, pulmonary tuberculosis, influenza, sinusitis, pharyngitis, sore throats and general respiratory tract infections). METHODS: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, articles from three large databases of scientific literature were included (Scopus, Web of Science and PubMed) for the period January 2000 to May 2020. RESULTS: A total of 70 economic analyses are included, most of which use decision tree modelling for diagnostic testing for respiratory tract infections in the community-care setting. Many studies do not incorporate a generally comparable clinical outcome in their cost-effectiveness analysis: fewer than half the studies (33/70) used generalisable outcomes such as quality-adjusted life-years. Other papers consider outcomes related to the accuracy of the test or outcomes related to the prescribed treatment. The time horizons of the studies generally are limited. CONCLUSIONS: The methods to economically assess diagnostic tests for respiratory tract infections vary and would benefit from clear recommendations from policy makers on the assessed time horizon and outcomes used. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40273-021-01054-1
Osteoarthritis:Mechanistic Insights, Senescence, and Novel Therapeutic Opportunities
Osteoarthritis (OA) is the most common joint disease. In the last years, the research community has focused on understanding the molecular mechanisms that led to the pathogenesis of the disease, trying to identify different molecular and clinical phenotypes along with the discovery of new therapeutic opportunities. Different types of cell-to-cell communication mechanisms have been proposed to contribute to OA progression, including mechanisms mediated by connexin43 (Cx43) channels or by small extracellular vesicles. Furthermore, changes in the chondrocyte phenotype such as cellular senescence have been proposed as new contributors of the OA progression, changing the paradigm of the disease. The use of different drugs able to restore chondrocyte phenotype, to reduce cellular senescence and senescence-associated secretory phenotype components, and to modulate ion channel activity or Cx43 appears to be promising therapeutic strategies for the different types of OA. In this review, we aim to summarize the current knowledge in OA phenotypes related with aging and tissue damage and the new therapeutic opportunities currently available
ANÁLISE PRELIMINAR DOS EQUIPAMENTOS DE ESPORTE E LAZER DA ORLA DE ATALAIA EM ARACAJU/SE: CONTRIBUIÇÕES PARA AS POLÍTICAS PÚBLICAS
Texto decorrente de pesquisa da Rede CEDESA nova Orla da Praia de Atalaia em Aracaju/SE se constitui em um cartão postal da cidade. Reformulada com diversos equipamentos para as práticas esportivas e de lazer, configura-se como um local “ideal” no tocante as opções de lazer para os aracajuanos e turistas que visitam a cidade.Rede Cedes/Ministério do Esport
Health-Economic Analyses of Diagnostics:Guidance on Design and Reporting
Cost-effectiveness analyses (CEAs) can be used to assess the value of diagnostics in clinical practice. Due to the introduction of the European in vitro diagnostic and medical devices regulations, more clinical data on new diagnostics may become available, which may improve the interest and feasibility of performing CEAs. We present eight recommendations on the reporting and design of CEAs of diagnostics. The symptoms patients experience, the clinical setting, locations of test sampling and analysis, and diagnostic algorithms should be clearly reported. The used time horizon should reflect the time horizon used to model the treatment after the diagnostic pathway. Quality-adjusted life-years (QALYs) or disability-adjusted life-years (DALYs) should be used as the clinical outcomes but may be combined with other relevant outcomes, such as real options value. If the number of tests using the same equipment can vary, the economy of scale should be considered. An understandable graphical representation of the various diagnostic algorithms should be provided to understand the results, such as an efficiency frontier. Finally, the budget impact and affordability should be considered. These recommendations can be used in addition to other, more general, recommendations, such as the Consolidated Health Economic Evaluation Reporting Standards (CHEERS) or the reference case for economic evaluation by the international decision support initiative
Biodegradable PEG–dendritic block copolymers: synthesis and biofunctionality assessment as vectors of siRNA
One important drawback of most of the currently used dendrimers for biomedical applications is their high stability under physiological conditions that can result in cytotoxicity or complications induced by the accumulation of non-degradable synthetic materials in the organism. Particularly in the gene therapy field, vector stability can further hinder the intracellular release of the nucleic acid from the dendriplex, consequently leading to low transfection efficiencies. Therefore, biodegradable cationic dendritic structures have been eagerly awaited. However, the development of these dendritic nanocarriers is challenging because of the undesired and/or premature degradation observed during their synthesis and/or application. Here, we report new hybrid-biodegradable, biocompatible, non-toxic, and water-soluble azide-terminated PEG–GATGE dendritic block copolymers, based on a gallic acid (GA) core and triethylene glycol (TG) butanoate arms, incorporating ester bonds (E) at the dendritic arms/shell. Their successful functionalization by “click” chemistry with unprotected alkynated amines allowed complexation and delivery of siRNA. The hydrophobic character of the GATGE building unit confers to these hydrolyzable dendritic bionanomaterials a great ability to complex, protect and mediate the cellular internalization of siRNA. Moreover, the localization of the degradation points at the dendritic periphery, close to the complexed siRNA, was found to be important for nucleic acid release from the nanoparticles, rendering a significant improvement of the transfection efficiency compared to their hydrolytically stable PEG–GATG copolymer counterparts. The present study puts forward these biodegradable PEG–dendritic block copolymers not only as suitable vectors for nucleic acids, but also as new avenues for further developments exploring their use in theranosticsThe authors would like to acknowledge the FEDER funds through the Programa Operacional Factores
de Competitividade – COMPETE and the Portuguese funds through FCT – Fundação para a Ciência e a
Tecnologia (PTDC/CTM-NAN/112428/2009 and PTDC/CTM-NAN/3547/2014) that supported this
work and the FCT / MEC through National Funds and, when applicable, co-financed by the FEDER via
the PT2020 Partnership Agreement under the 4293 Unit I&D. V. Leiro acknowledges the support by FCT (SFRH/BPD/69110/2010) and by the project NORTE-01-0145-FEDER-000012, financed by Norte
Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership
Agreement, through the European Regional Development Fund (ERDF). P.M.D. Moreno acknowledges
the support from the Marie Curie Actions of the European Community’s Seventh Framework Program
(PIEF-GA-2011-300485) and FCT fellowship (SFRH/BPD/108738/2015). This work was also financially
supported by the Spanish Government (MINECO: CTQ2012-34790, CTQ2012-33436) and the Xunta de
Galicia (CN2011/037)S
PROJETO ORLA: ANÁLISE DOS EQUIPAMENTOS DE ESPORTE E LAZER DA PRAIA DE ATALAIA EM ARACAJU/SE
Texto decorrente de pesquisa da Rede CEDESO presente estudo analisou a infraestrutura de esporte e lazer da Orla da praia de Atalaia em Aracaju/SE, com apoio financeiro da Rede CEDES/Ministério dos Esportes. A pesquisa identificou as condições de manutenção, acesso e uso dos equipamentos de esporte e lazer desse espaço. Para tal, foi realizado uma pesquisa observacional no local entre maio e dezembro de 2010 e aplicado 151 questionários a alguns frequentadores (amostra aleatória). Os dados do estudo indicam a predominância de equipamentos esportivos de lazer, em detrimentos dos infantis e culturais; um processo gradativo de privatização de alguns equipamentos públicos; a ausência de projetos e políticas públicas de incentivo ao pleno acesso da população aos equipamentos de lazer; estrutura diversificada de suporte ao lazer, mas com deficiências em relação aos banheiros públicos, transporte público e segurança no local. As conclusões indicam a necessidade do Estado de Sergipe e do Município de Aracaju reavaliarem e ampliarem as políticas públicas de esporte e lazer na Orla de Atalaia no que se refere a garantir o pleno acesso e uso da população local em relação a esse espaço, por vezes assegurado apenas aos turistas e as classes mais abastadas.Rede CEDES/Ministério do Esport
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