Origin of 1015−101610^{15}-10^{16}G Magnetic Fields in the Central Engine of Gamma Ray Bursts

Various authors have suggested that the gamma-ray burst (GRB) central engine is a rapidly rotating, strongly magnetized, $(\sim 10^{15}-10^{16}$ G) compact object. The strong magnetic field can accelerate and collimate the relativistic flow and the rotation of the compact object can be the energy source of the GRB. The major problem in this scenario is the difficulty of finding an astrophysical mechanism for obtaining such intense fields. Whereas, in principle, a neutron star could maintain such strong fields, it is difficult to justify a scenario for their creation. If the compact object is a black hole, the problem is more difficult since, according to general relativity it has "no hair" (i.e., no magnetic field). Schuster, Blackett, Pauli, and others have suggested that a rotating neutral body can create a magnetic field by non-minimal gravitational-electromagnetic coupling (NMGEC). The Schuster-Blackett form of NMGEC was obtained from the Mikhail and Wanas's tetrad theory of gravitation (MW). We call the general theory NMGEC-MW. We investigate here the possible origin of the intense magnetic fields $\sim 10^{15}-10^{16}$ G in GRBs by NMGEC-MW. Whereas these fields are difficult to explain astrophysically, we find that they are easily explained by NMGEC-MW. It not only explains the origin of the $\sim 10^{15}-10^{16}$G fields when the compact object is a neutron star, but also when it is a black hole.Comment: 9 pages, accepted for publication in JCA

Power Saving MAC Protocols in Wireless Sensor Networks: A Performance Assessment Analysis

Wireless sensor networks are an emerging technology that is used to monitor points or objects of interest in an area. Despite its many applications, this kind of network is often limited by the fact that it is difficult to provide energy to the nodes continuously, forcing the use of batteries, which restricts its operations. Network density may also lead to other problems. Sparse networks require stronger transmissions and have little redundancy while dense networks increase the chances of overhearing and interference. To address these problems, many novel medium access control (MAC) protocols have been developed through the years. The objective of this study is to assess the effectiveness of the T-MAC, B-MAC, and RI-MAC protocols in a variable density network used to collect data inside freight trucks carrying fruits that perish quickly. This article is part of the PrunusPós project, which aims to increase the efficiency of peach and cherry farming in Portugal. The comparison was done using the OMNET++ simulation framework. Our analysis covers the behavior and energetic properties of these protocols as the density of the network increases and shows that RI-MAC is more adaptable and consumes less energy than the alternatives.This study is within the activities of project “PrunusPós - Optimization of processes for the storage, cold conservation, active and/or intelligent packaging and food quality traceability in post-harvested fruit products”, project n. º PDR2020-101-031695, Partnership n.º 87, initiative n.º 175, promoted by PDR 2020 and co-funded by FEADER within Portugal 2020. P.D.G. thanks the support of Fundação para a Ciência e Tecnologia (FCT) and C-MAST - Centre for Mechanical and Aerospace Science and Technologies, under project UIDB/00151/2020. V. N. G. J. S. and J. M. L. P. C. acknowledge that this work is funded by FCT/MCTES through national funds and when applicable co-funded EU funds under the project UIDB/50008/2020. The authors would also like to acknowledge the company InspiringSci, Lda for its interest and valuable contribution to the successful development of this work.info:eu-repo/semantics/publishedVersio

Power saving MAC protocols in wireless sensor networks: a survey

In a wireless sensor network, energy is almost always the greatest limitation. Energy sources are restricted in many of the environments where nodes are deployed, limiting them to the use of batteries for power. Therefore, conserving energy is supremely important, however, such a task poses many challenges to hardware and protocol design. One of the greatest problems faced is reducing the energy consumption of the communications systems, which represents a substantial amount of the total consumption. This paper surveys the most recent schemes designed to reduce the communications module energy consumption with a focus on novel MAC protocols for ad-hoc wireless sensor networks. It initially describes the many challenges involved, then it analyses each protocol individually. Finally, the presented protocols are compared and the issues that remain open are raised for further research

THE ANKLE-HIP TRANSVERSE PLANE COUPLING DURING THE STANCE PHASE OF NORMAL WALKING

The aim of this study was to investigate the strength and features of a possibly existent ankle-hip transverse plane coupling during the stance of walking. Fifteen healthy volunteers walked on a 10m walkway in their natural speed using sandals. Kinematic data were obtained with a 3-dimensional motion analysis system. Calculation of the cross-correlation (r=-0.78) indicated a strong ankle-hip coupling, with ankle external rotation (foot pronation) coupled with hip internal rotation, and ankle internal rotation (foot supination) coupled with hip external rotation. Vector coding technique (Φ=41.01°) showed that ankle and hip joints present similar displacement magnitudes. The results agree with suggestions of ankle-hip transverse plane interdependency and an important kinetic energy transmission between the shank and thigh in this plane of movement

EFFECTS OF SIMULATING FOREFOOT VARISM INCREASES ON LOWER EXTREMITY KINEMATICS DURING THE STANCE PHASE OF WALKING

This study investigates the effects of simulating forefoot varism increases on lower extremity kinematics during the stance phase. Sixteen volunteers walked on a walkway in three conditions: wearing flat sandals; wearing a 5º and a 10º laterally wedged sandal. Data were obtained with a 3-D motion analysis system. The variables analyzed were: subtalar eversion/inversion; shank internal/external rotation; knee internal/external rotation; hip internal/external rotation. The simulations of 5º and 10º increases in forefoot varism increased subtalar pronation (P≤.007) and the simulation of 10º increased internal rotation of the shank in relation to the pelvis and of the hip (P=.001). The results suggest that forefoot varism can lead to kinematic patterns related to the occurrence of overuse injuries

The Origin of Magnetic Fields in Galaxies

Microgauss magnetic fields are observed in all galaxies at low and high redshifts. The origin of these intense magnetic fields is a challenging question in astrophysics. We show here that the natural plasma fluctuations in the primordial universe (assumed to be random), predicted by the Fluctuation-Dissipation-Theorem, predicts $\sim 0.034 \mu G$ fields over $\sim 0.3$ kpc regions in galaxies. If the dipole magnetic fields predicted by the Fluctuation-Dissipation-Theorem are not completely random, microgauss fields over regions $\gtrsim 0.34$ kpc are easily obtained. The model is thus a strong candidate for resolving the problem of the origin of magnetic fields in $\lesssim 10^{9}$ years in high redshift galaxies.Comment: 10 pages, 3 figure

Suplementação de ferro em pacientes com insuficiência renal crônica em hemodiálise: um ensaio clínico

OBJECTIVE: To evaluate iron deficiency and to compare effectiveness of oral and parenteral iron supplementation in end-stage renal disease, hemodialysis patients.PATIENTS AND METHODS: Thirty-nine end-stage renal disease, hemodialysis patients were evaluated for age; weight; etiology of chronic renal failure; duration of hemodialysis;  use of recombinant human erythropoietin; serum albumin, serum hemoglobin, hematocrit, and serum ferritin levels; and iron status. Iron status was assessed based on the following equation: [400 x log (serum ferritin) - log 30] - [150 x (11.55 - hemoglobin)] =iron status Patients were considered iron-deficient when the equation gave a negative result. Next, these patients were randomly divided into 2 groups. Patients with recent bleeding episodes or blood transfusion were excluded from the study. Group I received oral iron sulfate and group II intravenous iron hydroxide saccharate. The dosage was calculated basedon the iron status and body weight and adjusted for estimated bioavailability. RESULTS: Twenty-four (62%) patients were iron-deficient, out of which 19 completed the trial (11 patients in group I and 8 in group II). In the comparison with baseline values, group II had a significant increase in hematocrit (3.25 ± 3.69%, P < 0.05), serum hemoglobin (0.98 ± 0.86 g/dl, P < 0.02), serum ferritin (245 ± 133 ng/ml, P <0.01) and iron status (316.20 ± 214.230 mg, P < 0.01), whereas group I did not. In the comparison of group I and group II, the latter indicated greater increase in hematocrit, serum hemoglobin, serum ferritin and iron status (P < 0.05). Group II patients not using erythropoietin (5 of 8 patients), when compared to Group I, presented a greater increase in serum hemoglobin (0.8 ± 0.6 g/dl) and hematocrit (2.2± 3.4 %, P < 0.05). CONCLUSIONS: Considering equivalent dosages, intravenous iron therapy was more effective than oral therapy in increasing hematocrit, serum hemoglobin, serum ferritin, and iron status in hemodialysis patients with chronic renal disease. Patients not usingrecombinant human erythropoietin could benefit only from intravenous iron therapy.OBJETIVOS: Avaliar deficiência de ferro e comparar a efetividade da suplementação de ferro oral e parenteral nos pacientes renais crônicos em hemodiálise. PACIENTES E MÉTODOS: Trinta e nove pacientes com insuficiência renal crônica em hemodiálise foram avaliados para idade, peso, etiologia da insuficiência renal crônica, tempo em hemodiálise, uso de eritropoetina humana recombinante, albumina sérica,níveis de hematócrito e hemoglobina, ferritina sérica e grau de deficiência de ferro. Grau de deficiência de ferro foi avaliado pela equação: estado de ferro = [400 x log (ferritina sérica) - log 30] - [150 x (11,55 - hemoglobinasérica)] Deficiência de ferro foi considerada quando o resultado da equação era negativo. Estes pacientes foram randomizados aleatoriamente em 2 grupos. Os que apresentaram episódio de sangramento ou transfusão sanguínea recentes foram excluídos do estudo. O Grupo I recebeu ferro oral e o Grupo II, sacarato de hidróxido de ferro endovenoso. A dose foi calculada com base no estado de ferro e peso corporal e ajustada para biodisponibilidade estimada. RESULTADOS: Vinte e quatro pacientes (62%) estavam deficientes de ferro, sendo que 19 destes completaram o estudo, 11 pacientes no Grupo I e 8 no Grupo II . Comparado aos valores pré-tratamento com ferro, o Grupo II apresentou aumentossignificativos nos níveis de hematócrito (3,25 ± 3,69%, P < 0,05), hemoglobina sérica (0,98 ± 0,86g/dl, P < 0,02), ferritina sérica (245 ± 133ng/ml, P < 0,01) e no estado de ferro (316,20 ± 214,230mg, P < 0,01), o mesmo não ocorrendo no Grupo I. Ao comparar os dois grupos, o Grupo II apresentou aumentos maiores no hematócrito, hemoglobina sérica, ferritina sérica e estado de ferro do que o grupo I (P < 0,05). Cinco pacientes (62,5%) não usando eritropoetina (Grupo II) tiveram  aumentos maiores no hematócrito (2,2±3,4%) e na hemoglobina sérica (0,8±0,6g/dl) (P<0,05) comparados aos do Grupo I.CONCLUSÕES: Em doses equivalentes, a suplementação endovenosa de ferro foi mais efetiva do que a reposição oral em aumentar os níveis de hematócrito, hemoglobina sérica, ferritina sérica e estado de ferro nos pacientes renais crônicos em hemodiálise. Pacientes não usando eritropoetina humana recombinante apresentaram benefício somente com a suplementação parenteral de ferro na anemia.

ANÁLISE PARAMÉTRICA DO COMPORTAMENTO DE ELEMENTOS DE MEMBRANA APLICADA A ESTRUTURAS DE CONCRETO ARMADO VIA CONFIABILIDADE ESTRUTURAL

A importância do conhecimento do nível de segurança de uma estrutura é crucial para a realização de um bom projeto estrutural. Este artigo tem como objetivo fazer uma análise paramétrica em elementos de membrana de estruturas de concreto armado via confiabilidade estrutural. Para obtenção do nível de segurança do elemento de membrana o método de simulação de Monte Carlo foi utilizado. Uma variação determinística nos carregamentos aplicados sobre o elemento de membrana é feita e a contribuição de cada modo de falha considerada, obtendo-se assim, o índice de confiabilidade e sua variação com determinados parâmetros de projeto. Por meio de uma análise comparativa, ilustrada graficamente, o trabalho mostra diferentes casos de carregamentos no elemento de membrana, ocasionando modos de falhas distintos em cada situação. Os modos de falha estudados podem ser o escoamento do aço na direção x e/ou y, esmagamento do concreto e a falha do sistema como um todo. A presente metodologia tem como resultado principal o “controle”, pelo projetista, do nível de ductilidade de cada elemento de membrana e sua relação com os tipos possíveis de carregamentos atuantes. É possível, assim, obter o escoamento da armadura anteriormente ao esmagamento do concreto na maioria dos casos de carregamento

IFN-γ Production Depends on IL-12 and IL-18 Combined Action and Mediates Host Resistance to Dengue Virus Infection in a Nitric Oxide-Dependent Manner

Dengue is a mosquito-borne disease caused by one of four serotypes of Dengue virus (DENV-1–4). Severe dengue infection in humans is characterized by thrombocytopenia, increased vascular permeability, hemorrhage and shock. However, there is little information about host response to DENV infection. Here, mechanisms accounting for IFN-γ production and effector function during dengue disease were investigated in a murine model of DENV-2 infection. IFN-γ expression was greatly increased after infection of mice and its production was preceded by increase in IL-12 and IL-18 levels. In IFN-γ−/− mice, DENV-2-associated lethality, viral loads, thrombocytopenia, hemoconcentration, and liver injury were enhanced, when compared with wild type-infected mice. IL-12p40−/− and IL-18−/− infected-mice showed decreased IFN-γ production, which was accompanied by increased disease severity, higher viral loads and enhanced lethality. Blockade of IL-18 in infected IL-12p40−/− mice resulted in complete inhibition of IFN-γ production, greater DENV-2 replication, and enhanced disease manifestation, resembling the response seen in DENV-2-infected IFN-γ−/− mice. Reduced IFN-γ production was associated with diminished Nitric Oxide-synthase 2 (NOS2) expression and NOS2−/− mice had elevated lethality, more severe disease evolution and increased viral load after DENV-2 infection. Therefore, IL-12/IL-18-induced IFN-γ production and consequent NOS2 induction are of major importance to host resistance against DENV infection