Scalar and Spinor Particles in the Spacetime of a Domain Wall in String Theory

We consider scalar and spinor particles in the spacetime of a domain wall in the context of low energy effective string theories, such as the generalized scalar-tensor gravity theories. This class of theories allows for an arbitrary coupling of the wall and the (gravitational) scalar field. First, we derive the metric of a wall in the weak-field approximation and we show that it depends on the wall's surface energy density and on two post-Newtonian parameters. Then, we solve the Klein-Gordon and the Dirac equations in this spacetime. We obtain the spectrum of energy eigenvalues and the current density in the scalar and spinor cases, respectively. We show that these quantities, except in the case of the energy spectrum for a massless spinor particle, depend on the parameters that characterize the scalar-tensor domain wall.Comment: LATEX file, 21 pages, revised version to appear in Phys. Rev.

Linear Theory of Electron-Plasma Waves at Arbitrary Collisionality

The dynamics of electron-plasma waves are described at arbitrary collisionality by considering the full Coulomb collision operator. The description is based on a Hermite-Laguerre decomposition of the velocity dependence of the electron distribution function. The damping rate, frequency, and eigenmode spectrum of electron-plasma waves are found as functions of the collision frequency and wavelength. A comparison is made between the collisionless Landau damping limit, the Lenard-Bernstein and Dougherty collision operators, and the electron-ion collision operator, finding large deviations in the damping rates and eigenmode spectra. A purely damped entropy mode, characteristic of a plasma where pitch-angle scattering effects are dominant with respect to collisionless effects, is shown to emerge numerically, and its dispersion relation is analytically derived. It is shown that such a mode is absent when simplified collision operators are used, and that like-particle collisions strongly influence the damping rate of the entropy mode.Comment: 23 pages, 10 figures, accepted for publication on Journal of Plasma Physic

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Endovascular Abdominal Aneurysm Repair in Women: What are the Differences Between the Genders?

Introduction: Abdominal aortic aneurysm has a lower incidence in the female population, but a higher complication rate. It was been hypothesized that some anatomical differences of abdominal aortic aneurysm in women could be responsible for that. We proposed to analyze our data to understand the differences in the clinical and anatomical characteristics and the outcomes of patients undergoing endovascular aneurysm repair, according to gender. Methods: A retrospective analysis of patients undergoing endovascular aneurysm repair between 2001-2013 was performed. Patients were divided according gender and evaluated regarding age, atherosclerotic risk factors, aneurysm anatomic features, endograft type, anesthesic risk classification, length of stay, reinterventions and mortality. Two statistical studies were performed, first comparing women and men (Group A) and a second one comparing women and men, adjusted by age (Group B). Results: Of the 171 patients, only 5.8% (n=10) were females. Women were older (P<0.05) and the number of women with no atherosclerotic risk factor was significantly higher. The comparison adjusted by age revealed women with statistically less smoking history, less cerebrovascular disease and ischemic heart disease. Women had a trend to more complex anatomy, with more iliac intern artery aneurysms, larger aneurysm diameter and neck angulations statistically more elevated. No other variables were statistically different between age groups, neither reintervention nor mortality rates. Conclusion: Our study showed a clear difference in the clinical characteristics of women. The female population was statistically older, and when compared with men adjusted by age, had less atherosclerotic risk factors and less target organ disease. Women showed a more complex anatomy but with the same outcomes.info:eu-repo/semantics/publishedVersio

Is Age a Determinant Factor in EVAR as a Predictor of Outcomes or in the Selection Procedure? Our Experience

Introduction: Endovascular aneurysm repair (EVAR) is the therapy of choice in high risk patients with abdominal aortic aneurysm. The good results described are leading to the broadening of clinical indications to younger patients. However, reintervention rates seem higher and even with successful treatment sometimes there is growth of the aneurysm sac and rupture, meaning a failure of the therapeutic goal. This study proposes to analyse the impact of age in patients' selection and post-EVAR results. Methods: The clinical records of consecutive patients undergoing endovascular aneurysm repair, between 2001 and 2013, were retrospectively reviewed. Patients were divided according to age groups (80 years). Gender, body mass index, aneurysm anatomic features, neck characteristics, iliac morphology, surgical indication, endograft type, anesthesic risk classification, length of stay, reinterventions and mortality were analysed and compared. Results: The study included 171 patients, 161 (94.1%) men, and mean age 74.1±8.9 years. The age group under 70 had 32% of the patients. Only three characteristics were found different among age groups: 1) body mass index was higher in younger patients, with a considerable trend toward significance (P=0.06); 2) surgical indication, in the younger group, surgeon's and the patient's option were more proeminent (P<0.05); 3) erectile dysfunction was higher in elderly group (P<0.05). No other clinical and anatomical characteristics or final outcomes were found statisticaly different among age groups. Conclusion: The absence of statistically differences in mortality and reinterventions among age groups suggests that age by itself is not a relevant factor in endovascular aneurysm repair. Indeed, the three characteristics different in younger (obesity, sexual function and patient's choice) favor endovascular aneurysm repair.info:eu-repo/semantics/publishedVersio

Good neighbours: distribution of black-tufted marmoset (Callithrix penicillata) in an urban environment

Context Primates are one of the most charismatic and widely studied vertebrate groups. However, the study of new world primates in green patches within urban areas has been neglected. Such primates have been viewed as a source of human–animal conflict; however, their ecological importance to urban ecosystems and their role in human well being is poorly understood. Aims To increase understanding of both ecological and socioeconomical factors affecting the distribution, density and group sizes of urban marmosets in a large Brazilian city (Belo Horizonte). Methods A map of vegetation cover and land use was produced and employed to investigate the distribution of marmosets. An online questionnaire was extensively publicised, which permitted the public to report the occurrence or not of marmosets near their residences. For sites with low salary levels and low internet availability, face-to-face interviews were conducted. Additionally, field surveys were conducted in 120 green areas identified by spatial analysis as potential areas of occurrence. The human population density, salary levels and green areas were posteriorly correlated with marmoset distribution. Key results Despite the urbanisation and high human population density, green fragments within the city still housed marmoset groups. However, the presence of green areas did not always indicate primate presence. Group presence was significantly related to the size of parks or green areas and negatively related to built-up areas, and human density. Salary levels were related to more forested streets and possibly tolerance. Marmosets were classified as urban utilisers. Conclusions The human–wildlife conflict with marmoset species was relatively low, owing to marmoset avoidance of built-up areas. The interaction of marmoset species and city dwellers was mainly limited to borders of forest fragments and inside city parks, and appeared to be human motivated. Implications This study showed the importance of public involvement in wildlife studies in urban environments; clarifying the interaction between city dwellers and wild species is essential to mitigate negative interactions

Mesofauna do solo em ecossistemas de floresta primaria e de cultivos de seringueira e de cacaueiro no município de Capitão Poço, Pará.

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Efeitos hemorreológicos e cardiovasculares da eritropoietina num modelo de rato em exercício físico sob a acção de drogas

Recombinant human erythropoietin (rhEPO) has been therapeutically used for correction of anaemia. However, due to the increase in circulating red blood cells (RBCs) it promotes, thus increasing oxygen delivery to muscles and improving performance in sport, it has been also illegally used as sports doping. Besides the well known increase of hematocrit and blood viscosity; which might cause serious complications for the athletes, other disturbances could occur, whose mechanisms remain to be fully elucidated. This study aimed to evaluate the hemorheological and cardiovascular effects of administration of rhEPO to rats under chronic aerobic exercise. A ten week-protocol was performed in four male Wistar rat groups: control — sedentary; rhEPO — 50 IV/kg, 3 times/wk; exercised (EX) — swimming for 1 hr, 3 times/ wk; EX+rhEPO. rhEPO in trained rats promoted erythrocyte count increase, hypertension, heart hypertro-phy, sympathetic and serotonergic overactivation, as well as a trend to increased oxidative stress. In conclusion, rhEPO doping in rats under chronic exercise promotes not only the expected increased hematocrit, but also other serious deleterious cardiovascular and thromboembolic modifications, including live risk, which might be known and assumed by all sports authorities, including athletes and their physicians.info:eu-repo/semantics/publishedVersio

Características de adsorção de fósforo em solos da Bacia Petrolífera de Urucu.

Este trabalho teve como objetivos quantificar a adsorção de fósforo em solos originários de quatro locais da BOGPM, bacia petrolífera de Urucu, em Coari-AM, bem como avaliar a influência de alguns atributos do solo sobre esta característica

Influence of the concentration of locust bean gum on the gelling ability of whey peptic hydrolysates

The gelling ability of whey proteins can be changed by limited hydrolysis and by the presence of other components such as polysaccharides; depending on the environmental conditions it can either be improved or impaired. In this work the effect of LBG on the heat-set gelation of aqueous whey protein hydrolysates (10 % w/w) from pepsin was assessed at pH 7.0 by small deformation rheology. Whey protein concentrate (WPC) and hydrolysates with a degree of hydrolysis (DH) of 1.5, 2.5 and 4.9 % were used. Different LBG concentrations were tested: 0, 0.1, 0.3 and 0.55 % (w/w). The behaviour of gels from whey proteins or whey protein hydrolysates towards the presence of LBG was very similar. The evolution of the viscous and storage moduli followed the general behaviour reported for many biopolymer heat-set gelation processes including whey proteins gelation. The increase in the LBG concentration generally led to a decrease in the gel strength. However, for whey proteins a small amount of LBG (0.1 %) leads to a big enhancement in the gel strength probably due to an increase in the protein concentration of the protein enriched phase. Further increases in the LBG concentration led to a decrease in the gel strength. The gelation process is very sensible to environmental conditions and to processing and often leads to rather coarse data. The factorial planning used allowed validating conclusions using fewer experiments than those needed if no planning had been used, while still getting statistical significance out of the results. However, as many factors are involved, the modelling of the process was not straightforward