Interaction of glutathione transferase from horse erythrocytes with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole

7-Chloro-4-nitrobenzo-2-oxa-1,3-diazole reacts with two thiol groups of the dimeric horse erythrocyte glutathione transferase at pH 5.0, with strong inactivation reversible on dithiothreitol treatment. The inactivation kinetic follows a biphasic pattern, similar to that caused by other thiol reagents as recently reported. Both S-methylglutathione and 1-chloro-2,4-dinitrobenzene protect the enzyme from inactivation. Analysis of the reactive SH group-containing peptide gives the sequence Ala-Ser-Cys-Leu-Tyr, identical with that of the peptide that contains the reactive cysteine 47 of the human placental transferase. In the presence of glutathione, the enzyme is not inactivated by this reagent, but it catalyzes its conjugation to glutathione. At higher pH values, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole reacts with 2 tyrosines/dimer and lysines, as well as with cysteines. Reaction with lysine seems essentially without effect on activity; whether the reactive tyrosines are important for activity could not be determined using this reagent only. However, 2 tyrosines among the 4 that are nitrated by tetranitro-methane are important for activity

Temperature Regulation of Bacterial Production, Respiration, and Growth Efficiency in a Temperate Salt-marsh Estuary

There is consensus that temperature plays a major role in shaping microbial activity, but there are still questions as to how temperature influences different aspects of bacterioplankton carbon metabolism under different environmental conditions. We examined the temperature dependence of bacterioplankton carbon metabolism, whether this temperature dependence changes at different temperatures, and whether the relationship between temperature and carbon metabolism varies among estuarine sub-systems differing in their degree of enrichment. Two years of intensive sampling in a temperate estuary (Monie Bay, Chesapeake Bay, USA) revealed significant differences in the temperature dependence of bacterial production (BP) and respiration (BR), which drove a strong negative temperature response of bacterial growth efficiency (BGE). Accordingly, BGE was lower in summer (\u3c 0.2) and higher in winter (\u3e 0.5). For all measured metabolic processes, the most pronounced temperature response was observed at lower temperatures, with Q10 values generally 2-fold greater than in warmer waters. Despite significant differences in resource availability, both the temperature dependence and magnitude of BR and bacterioplankton carbon consumption (BCC) were remarkably similar among the 4 estuarine sub-systems. Although temperature dependencies of BP and BGE were also similar, their magnitude differed significantly, with highest values in the nutrient-enriched sub-system and lowest in the open bay. This pattern in carbon metabolism among sub- systems was present throughout the year and was confirmed by temperature manipulation experiments, suggesting the temperature effects on BP and BGE did not override the influence of resource availability. We conclude that temperature is the dominant factor regulating seasonality of BR and BCC in this system, whereas BP and BGE are influenced by both temperature and organic matter quality, with variation in the relative importance of each of these factors throughout the year

Cálculo de la longitud mínima de aproximación para una canaleta Parshall a través de la comparación del comportamiento hidráulico entre un modelo numérico y un modelo físico

Trabajo de InvestigaciónLa canaleta Parshall es una estructura hidraulica de gran empleabilidad dentro del campo de la Ingenieria, uno de sus usos es aforador de caudal o instrumento medidor. Pero en medio de su funcionalidad presenta problemas a la hora de encontrar obstaculos a la entrada de la canaleta, lo que hace que se alteren las laminas de agua, causando grandes problemas a su funcionalidad. El presente estudio propone un analisis en la longitud de aproximacion a la entrada de la canaleta en donde al interponer obstaculos, no se causara ninguna interferencia a las laminas de agua. Para el estudio efectivo se utiliza la herramienta computacional OpenFoam, con el fin de de determinar que longitud es la más exacta para no alterar las condiciones del flujo. De la misma manera estos resultados son comparados con un modelo a escala de laboratorioINTRODUCCIÓN 1. GENERALIDADES 2. MARCO DE REFERENCIA 3. METODOLOGIA 4. RESULTADOS 5. CONCLUSIONES 6. RECOMENDACIONES 7. ANEXOS 8. BIBLIOGRAFIAPregradoIngeniero Civi

The Large-Scale Polarization Explorer (LSPE)

The LSPE is a balloon-borne mission aimed at measuring the polarization of the Cosmic Microwave Background (CMB) at large angular scales, and in particular to constrain the curl component of CMB polarization (B-modes) produced by tensor perturbations generated during cosmic inflation, in the very early universe. Its primary target is to improve the limit on the ratio of tensor to scalar perturbations amplitudes down to r = 0.03, at 99.7% confidence. A second target is to produce wide maps of foreground polarization generated in our Galaxy by synchrotron emission and interstellar dust emission. These will be important to map Galactic magnetic fields and to study the properties of ionized gas and of diffuse interstellar dust in our Galaxy. The mission is optimized for large angular scales, with coarse angular resolution (around 1.5 degrees FWHM), and wide sky coverage (25% of the sky). The payload will fly in a circumpolar long duration balloon mission during the polar night. Using the Earth as a giant solar shield, the instrument will spin in azimuth, observing a large fraction of the northern sky. The payload will host two instruments. An array of coherent polarimeters using cryogenic HEMT amplifiers will survey the sky at 43 and 90 GHz. An array of bolometric polarimeters, using large throughput multi-mode bolometers and rotating Half Wave Plates (HWP), will survey the same sky region in three bands at 95, 145 and 245 GHz. The wide frequency coverage will allow optimal control of the polarized foregrounds, with comparable angular resolution at all frequencies.Comment: In press. Copyright 2012 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibite

Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model

Anthropogenic activities are causing widespread degradation of ecosystems worldwide, threatening the ecosystem services upon which all human life depends. Improved understanding of this degradation is urgently needed to improve avoidance and mitigation measures. One tool to assist these efforts is predictive models of ecosystem structure and function that are mechanistic: based on fundamental ecological principles. Here we present the first mechanistic General Ecosystem Model (GEM) of ecosystem structure and function that is both global and applies in all terrestrial and marine environments. Functional forms and parameter values were derived from the theoretical and empirical literature where possible. Simulations of the fate of all organisms with body masses between 10 µg and 150,000 kg (a range of 14 orders of magnitude) across the globe led to emergent properties at individual (e.g., growth rate), community (e.g., biomass turnover rates), ecosystem (e.g., trophic pyramids), and macroecological scales (e.g., global patterns of trophic structure) that are in general agreement with current data and theory. These properties emerged from our encoding of the biology of, and interactions among, individual organisms without any direct constraints on the properties themselves. Our results indicate that ecologists have gathered sufficient information to begin to build realistic, global, and mechanistic models of ecosystems, capable of predicting a diverse range of ecosystem properties and their response to human pressures

Predicting the spatial and temporal dynamics of species interactions in Fagus sylvatica and Pinus sylvestris forests across Europe

The productivity and functioning of mixed-species forests often differs from that of monocultures. However, the magnitude and direction of these differences are difficult to predict because species interactions can be modified by many potentially interacting climatic and edaphic conditions, stand structure and previous management. Process-based forest growth models could potentially be used to disentangle the effects of these factors and thereby improve our understanding of mixed forest functioning while facilitating their design and silvicultural management. However, to date, the predicted mixing effects of forest growth models have not been compared with measured mixing effects. In this study, 26 sites across Europe, each containing a mixture and monocultures of Fagus sylvatica and Pinus sylvestris, were used to calculate mixing effects on growth and yield and compare them with the mixing effects predicted by the forest growth model 3-PGmix. The climate and edaphic conditions, stand structures and ages varied greatly between sites. The model performed well when predicting the stem mass and total mass (and mixing effects on these components), with model efficiency that was usually >0.7. The model efficiency was lower for growth or smaller components such as foliage mass and root mass. The model was also used to predict how mixing effects would change along gradients in precipitation, temperature, potential available soil water, age, thinning intensity and soil fertility. The predicted patterns were consistent with measurements of mixing effects from published studies. The 3-PG model is a widely used management tool for monospecific stands and this study shows that 3-PGmix can be used to examine the dynamics of mixed-species stands and determine how they may need to be managed.This article is based upon work from COST Action EuMIXFOR, supported by COST (European Cooperation in Science and Technology). Funding for the Czech Republic site was provided by the MŠMT projects COST CZ – LD14063 and LD14074. All contributors thank their national funding institutions and the forest owners for agreeing to establish the plots and to measure and analyse data from the plots. The first author was funded by a Heisenberg Fellowship (FO 791/4-1) from the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG). Mário Pereira was supported by European Investment Funds by FEDER/COMPETE/POCI– Operacional Competitiveness and Internacionalization Programme, under Project POCI-01-0145-FEDER-006958 and National Funds by FCT – Portuguese Foundation for Science and Technology, under the project UID/AGR/04033/2013 as well as by project Interact-Integrative Research in Environment, Agro-Chain and Technology, NORTE-01-0145-FEDER-000017, research line BEST, co-financed by FEDER/NORTE 2020