Polyethylene naphthalate film as a wavelength shifter in liquid argon detectors

Liquid argon-based scintillation detectors are important for dark matter searches and neutrino physics. Argon scintillation light is in the vacuum ultraviolet region, making it hard to be detected by conventional means. Polyethylene naphthalate (PEN), an optically transparent thermoplastic polyester commercially available as large area sheets or rolls, is proposed as an alternative wavelength shifter to the commonly-used tetraphenyl butadiene (TPB). By combining the existing literature data and spectrometer measurements relative to TPB, we conclude that the fluorescence yield and timing of both materials may be very close. The evidence collected suggests that PEN is a suitable replacement for TPB in liquid argon neutrino detectors, and is also a promising candidate for dark matter detectors. Advantages of PEN are discussed in the context of scaling-up existing technologies to the next generation of very large ktonne-scale detectors. Its simplicity has a potential to facilitate such scale-ups, revolutionizing the field.Comment: 6 pages, 3 figure

Perturbed Spherically Symmetric Dust Solution of the Field Equations in Observational Coordinates with Cosmological Data Functions

Using the framework for solving the spherically symmetric field equations in observational coordinates given in Araujo and Stoeger (1999), their formulation and solution in the perturbed FLRW sperically symmetric case with observational data representing galaxy redshifts, number counts and observer area distances, both as functions of redshift on our past light cone, are presented. The importance of the central conditions, those which must hold on our world line C, is emphasized. In detailing the solution for these perturbations, we discuss the gauge problem and its resolution in this context, as well as how errors and gaps in the data are propagated together with the genuine perturbations. This will provide guidance for solving, and interpreting the solutions of the more complicated general perturbation problem with observational data on our past light cone.Comment: Latex 23 pages, no figures, submitted to Astrophysical Journa

A Comparison of Risk Exposure in Aquaculture and Agricultural Businesses

Agriculture and aquaculture have common features associated with their biological nature affecting risk exposure of the businesses. The aim of this paper is to compare risk exposure in salmon farming and agricultural enterprises in Norway by using an implicit error component model to examine the risk structure of yields, prices and economic returns at the farm level. Results indicate a higher farm-level year-to-year variability in yields, prices and economic returns in salmon farming than in agricultural enterprises. The variability in livestock enterprises was generally lower than for crop enterprises. Return on assets was highest in salmon farming with an average annual return of 9.2%. All of the agricultural farm types exhibited a negative average return on assets on average. Stochastic dominance tests of the distribution of economic returns from aquaculture and agricultural farm types showed salmon farming to be the most risk efficient alternative and salmon farming was most attractive from an investor’s perspective.Risk analysis, variability, Norway, Risk and Uncertainty,

Early Cretaceous non-marine bivalves from the Cameros and Basque-Cantabrian basins of Spain

Large unionids from the Weald facies of northern Spain are described. Three hundred seventeen specimens belonging to the Order Unionoida have been studied. Two species from the family Margaritiferidae were identified from the Cameros Basin. Margaritifera idubedae (Palacios and Sánchez, 1885) was recorded from the Urbión Group (Hauterivian-Barremian in age), being a very frequent bivalve in these fluvial sediments. Margaritifera valdensis (Mantell, 1844) was collected from the Enciso Group (Aptian in age) and is an uncommon bivalve in this lacustrine environment. A new genus with a new species called Protoanodonta conchae Delvene and Araujo, family Unionidae, is described from the Basque-Cantabrian Basin. Samples came from the Viviparus Bed Member (Vega de Pas Formation, Hauterivian-Barremian), interpreted as freshwater environment lacustrine in origin.Se han descrito las grandes náyades de las facies Weald del Norte de España. Se han estudiado trescientos diecisiete ejemplares pertenecientes al Orden Unionoida. Se han identificado dos especies de la Familia Margaritiferidae en la Cuenca de Cameros. Margaritifera idubedae (Palacios & Sánchez, 1885) se ha registrado en el Grupo Urbión (de edad Hauteriviense-Barremiense) siendo un bivalvo muy frecuente en estos materiales fluviales. Margaritifera valdensis (Mantell, 1844) ha sido registrada en el Grupo Enciso (de edad Aptiense) y es un bivalvo poco común en estos ambientes lacustres. Se ha definido un nuevo género que incluye una nueva especie, perteneciente a la Familia Unionidae, denominada Protoanodonta conchae Delvene and Araujo en la Cuenca Vasco-Cantábrica. Los ejemplares proceden del Miembro Capas de Viviparus (Formación Vega de Pas) y son de una edad Hauteriviense-Barremiense. Este ambiente de agua dulce se interpreta como lacustre

Mechanization of Conservation Agriculture in Brazil – An Overview

Overview on machinery commonly used in Brazil for main crops in conservation agriculture. The machinery is described and the problems are highlighted

Captação de água de chuva para agropecuária: consumo animal.

Propriedades e função da água; ingestão de água por diferentes espécies animais; capacidade de suporte forrageiro e hídrico de pequenas unidades de produção animal no semi-árido; captação e aproveitament de água de chuva para produção animal; captação de água de chuva para produção de forragens; consumo de água via alimentos

Gap junction reduction in cardiomyocytes following transforming growth factor- beta treatment and Trypanosoma cruzi infection

Gap junction connexin-43 (Cx43) molecules are responsible for electrical impulse conduction in the heart and are affected by transforming growth factor-beta (TGF-beta). This cytokine increases during Trypanosoma cruzi infection, modulating fibrosis and the parasite cell cycle. We studied Cx43 expression in cardiomyocytes exposed or not to TGF-beta T. cruzi, or SB-431542, an inhibitor of TGF-beta receptor type I (ALK-5). Cx43 expression was also examined in hearts with dilated cardiopathy from chronic Chagas disease patients, in which TGF-beta signalling had been shown previously to be highly activated. We demonstrated that TGF-beta treatment induced disorganised gap junctions in non-infected cardiomyocytes, leading to a punctate, diffuse and non-uniform Cx43 staining. A similar pattern was detected in T. cruzi-infected cardiomyocytes concomitant with high TGF-beta secretion. Both results were reversed if the cells were incubated with SB-431542. Similar tests were performed using human chronic chagasic patients and we confirmed a down-regulation of Cx43 expression, an altered distribution of plaques in the heart and a significant reduction in the number and length of Cx43 plaques, which correlated negatively with cardiomegaly. We conclude that elevated TGF-beta levels during T. cruzi infection promote heart fibrosis and disorganise gap junctions, possibly contributing to abnormal impulse conduction and arrhythmia that characterise severe cardiopathy in Chagas disease