5,825 research outputs found
Análisis de Ciclo de Vida para el ecodiseño del sistema Intemper TF de cubierta ecológica aljibe
The construction industry is one of the less sustainable activities on the planet: with a consumption of 40% of the materials entering the global economy and the generation of 40–50% of the global output of greenhouse gases. The biggest environmental impact caused by buildings is generated during their use phase due to the energy consumption for thermal conditioning. Addition of green elements to buildings is used to improve energy efficiency of buildings. In this study Life Cycle Assessment (LCA) methodology has been applied to quantify the environmental impact of the green roofs materials to analyze its environmental profile. The identification of hot spots of the system permits an ecodesign strategy that effectively reduces environmental burdens associated with roof construction, optimizing the environmental performance. The results identify the high environmental impact associated to the structure, the important contribution of the felt wick irrigation system and the extruded polystyrene thermal insulation.El sector de la construcción representa una de las actividades menos sostenibles del planeta: consume el 40% de los materiales de la economía global y genera el 40-50% de las emisiones de gases de efecto invernadero. El mayor impacto ambiental de los edificios se genera durante su fase de uso, debido al gasto energético de su acondicionamiento térmico. El uso de elementos vegetales es una de las estrategias empleadas para aumentar la eficiencia energética. En este trabajo se ha empleado la metodología de Análisis de Ciclo de Vida (ACV) para cuantificar el impacto ambiental de los materiales de la cubierta vegetal. Se han identificado los puntos críticos del sistema para establecer una estrategia de ecodiseño y reducir eficazmente las cargas ambientales. Los resultados obtenidos muestran la importancia del impacto ambiental del soporte estructural, la elevada contribución de la mecha de riego de fieltro y del aislamiento de poliestireno extrudido
Phase diagram of silicon from atomistic simulations
In this letter we present a calculation of the temperature-pressure phase
diagram of Si in a range of pressures covering from -5 to 20 GPa and
temperatures up to the melting point. The phase boundaries and triple points
between the diamond, liquid, -Sn and clathrate phases are
reported. We have employed efficient simulation techniques to calculate free
energies and to numerically integrate the Clausius-Clapeyron equation, combined
with a tight binding model capable of an accuracy comparable to that of
first-principles methods. The resulting phase diagram agrees well with the
available experimental data.Comment: 5 pages, 1 figure, accepted in PR
F2TE3: sistema de cerramiento transparente, ligero, de altas prestaciones energéticas que permite el diseño con formas libres
We propose a new lightweight, slim, high energy efficient, light-transmitting envelope system using VIP technology, providing for seamless, free-form designs for use in architectural projects. The research is based on envelope components already existing on the market, especially components implemented with aerogel insulation, as this is the most effective translucent thermal insulation there is today. This research revealed that no other insulation has all the features required of the proposed new envelope model. Even so, some systems, namely, VIP technology, monolithic aerogel used for insulation purposes, and polymethyl methacrylate (PMMA) barriers, do have properties that could be exploited to generate this envelope. Using these design elements, data from tests and independent studies, we have defined a new, variable geometry, envelope insulation system with excellent energy-saving levels.Se plantea un nuevo sistema de cerramiento monocasco ligero, de espesor mínimo, de alta eficiencia energética, mediante la utilización de tecnología tipo VIP 1, con un alto grado de transmisión de la luz, que permite el diseño con formas libres, para su utilización en proyectos arquitectónicos. La investigación se basa en el estudio de los elementos de cerramiento existentes en el mercado, en especial los implementados con aerogel como aislamiento térmico, ya que se trata del aislante transparente que mejores prestaciones ofrece actualmente, y determina que ninguno otro sistema de aislamiento cumple todas las prestaciones que se buscan con el nuevo sistema propuesto. Aún así, de ellos se pueden extraer cualidades para generarlo: la tecnología VIP, el aerogel monolítico como material aislante, y el Polimetilmetacrilato como material de encapsulado. Estos elementos de diseño nos han permitido definir, junto con ensayos realizados, y datos de estudios independientes, un nuevo sistema de cerramiento de formas libres que ofrece altas prestaciones energéticas
TL1A/DR3 axis involvement in the inflammatory cytokine network during pulmonary sarcoidosis
BACKGROUND:
TNF-like ligand 1A (TL1A), a recently recognized member of the TNF superfamily, and its death domain receptor 3 (DR3), firstly identified for their relevant role in T lymphocyte homeostasis, are now well-known mediators of several immune-inflammatory diseases, ranging from rheumatoid arthritis to inflammatory bowel diseases to psoriasis, whereas no data are available on their involvement in sarcoidosis, a multisystemic granulomatous disease where a deregulated T helper (Th)1/Th17 response takes place.
METHODS:
In this study, by flow cytometry, real-time PCR, confocal microscopy and immunohistochemistry analyses, TL1A and DR3 were investigated in the pulmonary cells and the peripheral blood of 43 patients affected by sarcoidosis in different phases of the disease (29 patients with active sarcoidosis, 14 with the inactive form) and in 8 control subjects.
RESULTS:
Our results demonstrated a significant higher expression, both at protein and mRNA levels, of TL1A and DR3 in pulmonary T cells and alveolar macrophages of patients with active sarcoidosis as compared to patients with the inactive form of the disease and to controls. In patients with sarcoidosis TL1A was strongly more expressed in the lung than the blood, i.e., at the site of the involved organ. Additionally, zymography assays showed that TL1A is able to increase the production of matrix metalloproteinase 9 by sarcoid alveolar macrophages characterized, in patients with the active form of the disease, by reduced mRNA levels of the tissue inhibitor of metalloproteinase (TIMP)-1.
CONCLUSIONS:
These data suggest that TL1A/DR3 interactions are part of the extended and complex immune-inflammatory network that characterizes sarcoidosis during its active phase and may contribute to the pathogenesis and to the progression of the disease
La girolline, nouvelle substance antitumorale extraite de l'éponge, Pseudaxinyssa cantharella n. sp. (Axinellidae)
Une nouvelle substance antitumorale a été isolée d'une Eponge néo-calédonienne, #Pseudaxinyssa cantharella$. Sa structure a été établie à l'aide de ses caractéristiques spectrales et par préparation de dérivés sélectivement substitués. (Résumé d'auteur
Los Materiales de Cambio de Fase (MCF) empleados para la acumulación de energía en la arquitectura. Su aplicación en el prototipo Magic Box
The article shows an energy-accumulation system in change of phase materials, designed for a prototype dwelling used for building two bioclimatic and self-sufficient buildings. These bulidings have been built in Madrid, Washington and Beijing. The characteristics of these materials, the construction systems into which these materials were incorporated, its comparative valuation with sensitive accumulation systems, and the results of the building monitorization are included.El artículo muestra un sistema de acumulación de energía en Materiales de Cambio de Fase diseñado para un prototipo de vivienda con el que se han construido dos edificios bioclimáticos y autosuficientes. Estos edificios se han realizado en Madrid, Washington y Pekín. Se incluyen las características de estos materiales, de los sistemas constructivos donde se integraron, su valoración comparativa con los sistemas de acumulación sensibles y los resultados de la monitorización del edificio
Dairy Intake and Risk of Cognitive Decline and Dementia: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies
Dairy intake may influence cognition through several molecular pathways. However, epidemiologic studies yield inconsistent results, and no dose-response meta-analysis has been conducted yet. Therefore, we performed a systematic review with a dose-response meta-analysis about the association between dairy intake and cognitive decline or incidence of dementia. We investigated prospective studies with a follow-up ≥6 mo on cognitive decline or dementia incidence in adults without known chronic conditions through a systematic search of Embase, Medline, Cochrane Library, Web of Science, and Google Scholar from inception to 11 July 2023. We evaluated the dose-response association using a random-effects model. We identified 15 eligible cohort studies with >300,000 participants and a median follow-up of 11.4 y. We observed a negative nonlinear association between cognitive decline/dementia incidence and dairy intake as assessed through the quantity of consumption, with the nadir at ∼150 g/d (risk ratio: 0.88; 95% confidence interval: 0.78, 0.99). Conversely, we found an almost linear negative association when we considered the frequency of consumption (risk ratio for linear trend: 0.84; 95% confidence interval: 0.77, 0.92 for 1 time/d increase of dairy products). Stratified analysis by dairy products showed different shapes of the association with linear inverse relationship for milk intake, whereas possibly nonlinear for cheese. The inverse association was limited to Asian populations characterized by generally lower intake of dairy products, compared with the null association reported by European studies. In conclusion, our study suggests a nonlinear inverse association between dairy intake and cognitive decline or dementia, also depending on dairy types and population characteristics, although the heterogeneity was still high in overall and several subgroup analyses. Additional studies should be performed on this topic, including a wider range of intake and types of dairy products, to confirm a potential preventing role of dairy intake on cognitive decline and identify ideal intake doses. This review was registered at PROSPERO as CRD42020192395
Algebra of Lax Connection for T-Dual Models
We study relation between T-duality and integrability. We develop the
Hamiltonian formalism for principal chiral model on general group manifold and
on its T-dual image. We calculate the Poisson bracket of Lax connections in
T-dual model and we show that they are non-local as opposite to the Poisson
brackets of Lax connection in original model. We demonstrate these calculations
on two specific examples: Sigma model on S(2) and sigma model on AdS(2).Comment: 24 pages, references adde
The impact of socioeconomic and phenotypic traits on self-perception of ethnicity in Latin America
Self-perception of ethnicity is a complex social trait shaped by both, biological and non-biological factors. We developed a comprehensive analysis of ethnic self-perception (ESP) on a large sample of Latin American mestizos from five countries, differing in age, socio-economic and education context, external phenotypic attributes and genetic background. We measured the correlation of ESP against genomic ancestry, and the influence of physical appearance, socio-economic context, and education on the distortion observed between both. Here we show that genomic ancestry is correlated to aspects of physical appearance, which in turn affect the individual ethnic self-perceived ancestry. Also, we observe that, besides the significant correlation among genomic ancestry and ESP, specific physical or socio-economic attributes have a strong impact on self-perception. In addition, the distortion among ESP and genomic ancestry differs across age ranks/countries, probably suggesting the underlying effect of past public policies regarding identity. Our results indicate that individuals’ own ideas about its origins should be taken with caution, especially in aspects of modern life, including access to work, social policies, and public health key decisions such as drug administration, therapy design, and clinical trials, among others
Manejo terapéutico y diagnóstico en equipo multidisciplinario y resultados obtenidos en gestantes con cardiopatía orgánica
Las enfermedades cardiovasculares afectan aproximadamente al 2% de las mujeres embarazadas, por lo que suponen un aumento del riesgo tanto para la madre como para el feto. El embarazo y el parto producen cambios fisiológicos sustanciales que requieren de una adecuada adaptación del sistema cardiovascular. Estos cambios fisiológicos que son muy bien tolerados en las gestantes sin cardiopatía, exponen a la mujer con enfermedad cardiovascular a eventos clínicos significativos. Este es un trabajo descriptivo, retrospectivo, de casos consecutivos de pacientes que acudieron a la División de Medicina Cardiovascular, del Hospital de Clínicas en un período comprendido entre Agosto de 2013 a Junio de 2014. Incluye a 5 pacientes embarazas y portadoras de cardiopatías conocidas o desconocidas. La edad promedio fue de 27 años, rango etario de 17 a 36 años. La edad gestacional al momento de la consulta fue de 34 semanas por fecha de última menstruación, menor edad gestacional 30 semanas y mayor edad gestacional 38 semanas. El síntoma principal de consulta fue la disnea (100%), edema de miembros inferiores en 3 pacientes (60%), y palpitaciones en 2 pacientes (40%). El manejo diagnóstico y terapéutico conjunto con un seguimiento detallado y adecuado por un equipo multidisciplinario de cardiólogos, clínicos, ginecólogos, anestesiólogos y cirujanos cardiovasculares facilitan una buena evolución clínica y un desenlace exitoso del embarazo y parto de la gestante con la cardiopatía orgánica. Como resultado de este manejo multidisciplinario todos los recién nacidos tuvieron buena evolución durante su permanencia en la unidad de cuidados intensivos sin inconvenientes
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