Yukawa particles in a confining potential

We study the density distribution of repulsive Yukawa particles confined by an external potential. In the weak coupling limit, we show that the mean-field theory is able to accurately account for the particle distribution. In the strong coupling limit, the correlations between the particles become important and the mean-field theory fails. For strongly correlated systems, we construct a density functional theory which provides an excellent description of the particle distribution, without any adjustable parameters.Comment: Submitte

Interaction between random heterogeneously charged surfaces in an electrolyte solution

We study, using Monte Carlo simulations, the interaction between infinite heterogeneously charged surfaces inside an electrolyte solution. The surfaces are overall neutral with quenched charged domains. An average over the quenched disorder is performed to obtain the net force. We find that the interaction between the surfaces is repulsive at short distances and is attractive for larger separations

Effect of dielectric discontinuity on a spherical polyelectrolyte brush

In this paper we perform molecular dynamics simulations of a spherical polyelectrolyte brush and counterions in a salt-free medium. The dielectric discontinuity on the grafted nanoparticle surface is taken into account by the method of image charges. Properties of the polyelectrolyte brush are obtained for different parameters, including valency of the counterions, radius of the nanoparticle, and the brush total charge. The monovalent counterions density profiles are obtained and compared with a simple mean-field theoretical approach. The theory allows us to obtain osmotic properties of the system

Application of artificial vascular polyvinyl alcohol hydrogel grafts in sheep - our experience to date.

Researchers developed this project according with the tasks originally planned, so far focusing their research activities in the biocompatibility and functionality of vascular implants. The biocompatibility was studied by following the ISO standard 10993-6 for evaluation of medical devices through the evaluation and grading of inflammation caused by implants placed subcutaneously. The implants were placed in sheep and collected randomly at different time points of the experimental period and subsequently processed histologically and classified according to Annex E to the standard mentioned above. The functionality of vascular implants has been evaluated to date by replacement of segments of the carotid by ePTFE implants with 5 cm long and 4 mm in diameter, coated or not with cultured stem cells. The deployment of these prostheses has been performed in carotid arteries of sheep and their functional performance measured by vascular ultrasound in Doppler and B mode by measuring parameters such as: peak systolic / diastolic blood flow velocity, vascular diameters at implantation and at the periphery of these. These measurements are performed at various time points of the experiment were folloed by euthanasia of sheep and immediately sample collection for the implementation of techniques like immunohistochemistry, morphometry and scanning electronic microscopy. Complications were observed throughout the experimental period include the formation of thrombi after at the transition implantcarotid region and vascular dilatation as the most frequent, respectively, in periods of short-and long-term experiment

Evaluating the impact of extreme temperature based indices in the 2003 heatwave excessive mortality in Portugal

This paper analyses the impact of the 2003 European heatwave on excessive human mortality in Portugal, a country that presents a relatively high level of exposure to heatwave events. A total of 2399 excessive deaths are estimated in continental Portugal, which implies an increase of 58% over the expected deaths. When these values are split by gender, it is seen that women increase (79%), was considerably higher than that recorded for men (41%). The increment of mortality due to this heatwave was detected for all the 18 districts of the country, but its magnitude was significantly higher in the inner districts close to the Spanish border. When we split by gender all districts reveal significant mortality increments for women, while the impact in men’s excess deaths is not significant over 3 districts. Several temperature derived indices were used and evaluated in their capacity to explain, at the regional level, the excessive mortality (ratio between observed and expected deaths) by gender. It is shown that the best relationship is found for the total exceedance of extreme days, an index combining the length of the heatwave and its intensity. Both variables hold a linear relationship with r = 0.79 for women and a poorer adjustment (r = 0.50) for men. Additionally, availability of mortality data split by age also allowed obtaining detailed information on the structure of the population in risk, namely by showing that statistically significant increments are concentrated in the last three age classes (45–64, 65–74 and 75 or more). The use of air conditioning systems in some Portuguese hospitals had a major impact on the decrease (up to 40%) in excessive mortality values. A finer approach is relevant for prevention strategies, since it allows to identify better the target population of any preventive strategy regional and national authorities may be interested to implement

An extrasolar planetary system with three Neptune-mass planets

Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called 'hot Neptunes' or 'super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15 days. Here we report a system of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by an asteroid belt within 1 AU (the Sun-Earth distance). Simulations show that the system is in a dynamically stable configuration. Theoretical calculations favour a mainly rocky composition for both inner planets, while the outer planet probably has a significant gaseous envelope surrounding its rocky/icy core; the outer planet orbits within the habitable zone of this star.Comment: 17 pages, 3 figures, preprint of the paper published in Nature on May 18, 200

An Eco-Energetic performance comparison of dehumidification systems in High-Moisture indoor environments

This study discusses the choice of dehumidification systems for high-moisture indoor environments, such as indoor swimming pools, supported by an eco-energetic performance comparison. Initially, the causes of the high relative humidity and condensation in these spaces are reported, as well as the available dehumidification technologies. Two different solutions are described: desiccant wheel dehumidification and re-cooling. The energy demand required by a refrigeration system is lower than the desiccant wheel; however, the former system requires less maintenance and does not require refrigerant fluid. An eco-energetic comparison is performed between the two systems in two countries with different energy matrices (Brazil and USA). In Brazil, the desiccant wheel is the best choice for the past 10 years, with a predicted 351,520 kgCO2 of CO2 emissions, which is 38% lower than the refrigeration system. In the USA, the best option is the refrigeration system (1,463,350 kgCO2), a 12% more efficient option than desiccant wheels. This model can be considered for energy and CO2 emissions assessment, predicting which system has better energy efficiency and lower environmental impact, depending on the refrigerant type, location and environmental conditions.info:eu-repo/semantics/publishedVersio

The revolving door : evidence from the United Kingdom, Germany, France, Spain, Belgium, Greece and Brazil

The following study analyses the academic background and careers of 175 members of Governments and Central Banks of seven countries (Belgium, Brazil, France, Germany, Greece, Spain and United Kingdom) for the years 1975 and 2015, in order to verify whether the “Revolving Door Theory” can be applied to these cases. After some research on the curricula vitae of the members of Governments and Central Banks, we found that, for instance, that more Government and Central Bank members studied abroad for the case of the UK and US than for the other countries. We also found that it is more common for Central Bank executive members to obtain PhDs than it is the case for Government members. Moreover, external promotions in the Central Banks in 1975 were quite relevant but no cases were registered for 2015; for Governments, the trend was the exact opposite, no external promotions in 1975 but many cases in 2015. While it is not possible to find irrefutable evidence to sustain the Revolving Door hypothesis, it is still possible to find recurrent patterns in different countries that may be explained by that theory. More expanded databases and a larger selection of countries is required for that analysis

Evolution of Black-Box Models Based on Volterra Series

This paper presents a historical review of the many behavioral models actually used to model radio frequency power amplifiers and a new classification of these behavioral models. It also discusses the evolution of these models, from a single polynomial to multirate Volterra models, presenting equations and estimation methods. New trends in RF power amplifier behavioral modeling are suggested

Unraveling the insights into phage endolysin association

In view of the abundacy of phages (1), even rare phage-induced events are frequent at the global level. They have a staggering ecological impact on the bacterial population and in the evolution of bacterial genomic structure upon virus-host interactions, acting as agents in the recycling of organic matter and presenting a valuable tool in molecular biology and epidemiology. Th focus on genomic research have revealed information on open reading frames of proteins of interest (2). Increasing interest has been given to phage (endo )lysins in molecular biology, biotechnology and medicine. Lysins are phage lytic enzymes that break down the peptidoglycan of the bacterial cell wall at the terminal stage of the phage reproduction cycle, to release the phage progeny with the consequent death of the bacterial cells (3). Despite the increasing number of genomes in Genbank:, no effort has been made so far to understand the relation between lysins and their phage family and host species, presenting challenges in their annotation, comparative analysis, and representation. The almost 700 complete phage genomes deposited in the NCBI database were searched for the presence of lysins by making use of the pfam ( 4) identified domains and BLAST comparison of putative/unidentified complete genome against known lysins. In approximately 5% of the phage genomes it was not possible to identify any lysin. The identified enzymes were used to construct a phylogenetic tree with Phylip (5), using Neighbor-Joining, Maximum Likelihood and Parsimony algorithms (6). From the resulting tree, we were able to present a phage-lysin characterization network analysis taking into account the lysin aa sequence and the different phage classes (Family/Genus) and host species to study their evolutionary stories. Regarding the phage families, muramidases, amidases and peptidases are the largest type of lysins in Myoviridae, Podoviridae and Siphoviridae phages respectively. Grouped data will also be used to identify conserved domains among lysins of different phages which will play an important role in the annotation of the unidentified lytic cassette of sequenced phages