Static and dynamic properties of vortices in anisotropic magnetic disks

We investigate the effect of the magnetic anisotropy ($K_z$) on the static and dynamic properties of magnetic vortices in small disks. Our micromagnetic calculations reveal that for a range of $K_z$ there is an enlargement of the vortex core. We analyze the influence of $K_z$ on the dynamics of the vortex core magnetization reversal under the excitation of a pulsed field. The presence of $K_z$, which leads to better resolved vortex structures, allows us to discuss in more details the role played by the in-plane and perpendicular components of the gyrotropic field during the vortex-antivortex nucleation and annihilation.Comment: 4 pages, 4 figure

Sen, Sraffa and the revival of classical political economy

Copyright © 2012 Taylor & Francis.In his new book The Idea of Justice, Amartya Sen argues that political theory should not consist only in the characterisation of ideal situations of perfect justice. In so doing, Sen is making, within the context of political theory, a similar argument to another he also made in economic theory, when crtiticising what he called the ‘rational fool’ of mainstream economics. Sen criticised the ideal and fictitious agent of mainstream economics, while advocating for a return to an integrated view of ethics and economics, which characterised many classical political economists who inspired Sen's theory of justice, from Adam Smith to Karl Marx. I will examine Sen's revival of classical political economy, and argue that a revival of classical political economy, which was undertaken earlier by Piero Sraffa, has much potential for bringing a more plural and realist perspective to economics

Evidence of seasonal price transmission in the soybean international Market

The paper aims consists to analyze price transmission system in soybean international market. Initially is determined the price causality in soybean international market utilizing prices series from Chicago Board ofTrade (CBOT), Rotterdam, Brazil and Argentina, production and commercialization main centers. Second, seasonal behavior of the price series was evaluated using X-12 method. The results obtained showed that causality directions among the analyzed price series are unidirectional. The seasonal behavior analysis indicated that Rotterdam price, at the crop time in South Hemisphere, is more similar to Brazilian and Argentina prices. On the other hand, Rotterdam prices align with CBOT quotation in North Hemisphere crop time. This result is due to the fact that soybean consumption in European Union, the largest international soybean buyer, to remains constant during the year. Last, the paper concludes that international soybean market presents a price transmission system based on seasonal behavior

Motivation and frustration in cardiology trial participation: The patient perspective

OBJECTIVE: The participation of humans in clinical cardiology trials remains essential, but little is known regarding participant perceptions of such studies. We examined the factors that motivated participation in such studies, as well as those that led to participant frustration. METHODS: Patients who had participated in hypertension and coronary arterial disease (phases II, III, and IV) clinical trials were invited to answer a questionnaire. They were divided into two groups: Group I, which included participants in placebo-controlled clinical trials after randomization, and Group II, which included participants in clinical trials in which the tested treatment was compared to another drug after randomization and in which a placebo was used in the washout period. RESULTS: Eighty patients (47 patients in Group I and 33 patients in Group II) with different socio-demographic characteristics were interviewed. Approximately 60% of the patients were motivated to participate in the trial with the expectation of personal benefit. Nine participants (11.2%) expressed the desire to withdraw, which was due to their perception of risk during the testing in the clinical trial (Group I) and to the necessity of repeated returns to the institution (Group II). However, the patients did not withdraw due to fear of termination of hospital treatment. CONCLUSIONS: Although this study had a small patient sample, the possibility of receiving a benefit from the new tested treatment was consistently reported as a motivation to participate in the trials

Um Novo Método Simultâneo de Sexta Ordem Tipo Ehrlich para Zeros Polinomiais Complexos

This paper presents a new iterative method for the simultaneous determination of simple polynomial zeros. The proposed method is obtained from the combination of the third-order Ehrlich iteration with an iterative correction derived from Li's fourth-order method for solving nonlinear equations. The combined method developed has order of convergence six. Some examples are presented to illustrate the convergence and efficiency of the proposed Ehrlich-type method with Li correction for the simultaneous approximation of polynomial zeros.Este artigo apresenta um novo método iterativo para a determinação simultânea de zeros polinomiais simples. O~método proposto é obtido a partir da combinação da iteração de Ehrlich de terceira ordem com uma correção iterativa derivada do método de Li de quarta ordem para a resolução de equações não lineares. O método combinado desenvolvido tem ordem de convergência seis. Alguns exemplos são apresentados para ilustrar a convergência e eficiência do método tipo Ehrlich com correção de Li proposto para a aproximação simultânea de zeros polinomiais

Surface Changes Of WaveOne™ and Reciproc® Instruments after Using Three Times for Preparation of Simulated Curved Canals with and without Glide Path

Introduction: This study evaluated the occurrence of morphological changes on the surface of the instruments WaveOne™ and Reciproc® when used in the preparation of simulated curved canals with and without glide path (generated with the Pathfile™ system), after the first, second, and third uses. Materials and methods: Sixty-four resin blocks, which simulated curved root canals, were used and instrumented with a variety of instruments, grouped according to manufacturer and conditions of simulated canal preparation. Simulated canals were instrumented with WaveOne™ (GW1 group) and Reciproc® (GR1 group) according to manufacturers’ recommendations, respectively. In contrast, GW2 and GR2 groups’ simulated canals were submitted for construction of glide path with the PathFile™ system before the use of WaveOne™ and Reciproc® instruments, respectively. Each instrument was used three times; after each use, each instrument was analyzed by using scanning electron microscopy (cervical, middle, and apical thirds of the instrument) in order to characterize the occurrence of changes (fracture, twist, and crack). Data were described using means and standard deviations. We used generalized linear models to compare differences between factors (region, manufacturer, glide path, and number of uses). SPSS-15 software was used, with a significance level of 5%.Results: Without glide path, WaveOne™ instruments tended to fracture more frequently (P=0.003), twist more frequently (P=0.05), and crack more frequently (P=0.022), with increasing use, with statistically significant differences. With glide path, both WaveOne™ and Reciproc® instruments cracked less frequently (P=0.001); Reciproc® instruments did not exhibit superficial changes, such as fractures and/or twists. Conclusion: In this in vitro study Reciproc® instruments exhibited superior performance, compared with WaveOne™ instruments, particularly when glide path with the PathFile™ system was used; both instruments may be used, safely, three times to prepare curved canals.Keywords: Endodontics; Root Canal Preparation; Root Canal Therapy; Scanning Electron Microscop

Scaling limit of an equilibrium surface under the Random Average Process

We consider the equilibrium surface of the Random Average Process started from an inclined plane, as seen from the height of the origin, obtained in [Ferrari & Fontes, 1998], where its fluctuations were shown to be of order of the square root of the distance to the origin in one dimension, and the square root of the log of that distance in two dimensions (and constant in higher dimensions). Remarkably, even if not pointed out explicitly in [Ferrari & Fontes, 1998], the correlation structure of those fluctuations is given in terms of the Green's function of a certain random walk, and thus corresponds to those of Discrete Gaussian Free Fields. In the present paper we obtain the scaling limit of those fluctuations in one and two dimensions, in terms of Gaussian processes, in the sense of finite dimensional distributions. In one dimension, the limit is given by Brownian Motion; in two dimensions, we get a process with a discontinuous covariance function.Comment: 23 page

Geochemistry of acid mine drainage from a coal mining area and processes controlling metal attenuation in stream waters, southern Brazil

Acid drainage influence on the water and sediment quality was investigated in a coal mining area (southern Brazil). Mine drainage showed pH between 3.2 and 4.6 and elevated concentrations of sulfate, As and metals, of which, Fe, Mn and Zn exceeded the limits for the emission of effluents stated in the Brazilian legislation. Arsenic also exceeded the limit, but only slightly. Groundwater monitoring wells from active mines and tailings piles showed pH interval and chemical concentrations similar to those of mine drainage. However, the river and ground water samples of municipal public water supplies revealed a pH range from 7.2 to 7.5 and low chemical concentrations, although Cd concentration slightly exceeded the limit adopted by Brazilian legislation for groundwater. In general, surface waters showed large pH range (6 to 10.8), and changes caused by acid drainage in the chemical composition of these waters were not very significant. Locally, acid drainage seemed to have dissolved carbonate rocks present in the local stratigraphic sequence, attenuating the dispersion of metals and As. Stream sediments presented anomalies of these elements, which were strongly dependent on the proximity of tailings piles and abandoned mines. We found that precipitation processes in sediments and the dilution of dissolved phases were responsible for the attenuation of the concentrations of the metals and As in the acid drainage and river water mixing zone. In general, a larger influence of mining activities on the chemical composition of the surface waters and sediments was observed when enrichment factors in relation to regional background levels were used.Influência de drenagem ácida sobre a qualidade de água e sedimento foi investigada em uma área de mineração de carvão (sul do Brasil). A drenagem ácida mostrou pH entre 3,2 e 4,6 e elevadas concentrações de sulfato, As e metais, dos quais, Fe, Mn e Zn excederam os limites para emissão de efluentes da legislação brasileira. Arsênio também excedeu levemente o limite. Poços de monitoramento de água subterrânea situados em áreas de mina ativa e pilhas de rejeitos revelaram intervalo de pH e concentrações químicas semelhantes aqueles da drenagem ácida. Entretanto, amostras de águas subterrânea e de rio utilizadas para o abastecimento público municipal revelaram pH entre 7,2 e 7,5 e baixas concentrações químicas, embora a concentração de Cd tenha superado um pouco o limite adotado pela legislação brasileira para águas subterrâneas. Em geral, as águas de superfície mostraram grande intervalo de pH (6 a 10,8), e a influência da drenagem ácida em sua composição química não foi muito significativa. Localmente, drenagem ácida parece ter dissolvido rochas carbonáticas presentes na sequência estratigráfica local, atenuando a dispersão de metais e As. Anomalias destes elementos foram encontradas em sedimentos de corrente, e elas foram fortemente dependentes da proximidade de depósitos de rejeitos e minas abandonadas. Neste trabalho, processos de precipitação em sedimentos e diluição de fases dissolvidas foram considerados como os principais mecanismos responsáveis pela atenuação das concentrações de metais e As nas zonas de mistura entre drenagem ácida e água fluvial. Em geral, observou-se uma maior influência das atividades de mineração sobre a composição química de águas superficiais e sedimentos quando fatores de enriquecimento em relação aos níveis de background regionais foram utilizados.53955

Adição de funções de criptografia simétrica em um applet de código aberto com suporte via middleware OpenSC

TCC(graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. Ciências da Computação.O sigilo dos dados é um dos principais pilares da segurança em computação. Dentre as diferentes formas para alcançá-lo, vale destacar o uso de chaves secretas. Com elas, pode-se cifrar informações sensíveis utilizando algoritmos de criptografia simétrica em que a chave é compartilhada entre o remetente e o destinatário. A mesma chave realiza as operações de cifragem e decifragem dos dados. Neste contexto, o maior problema é o armazenamento da chave de forma segura. Dentre as possíveis maneiras de armazená-la, pode-se citar: banco de dados local, servidores e Smart Cards. Sendo o enfoque deste trabalho, o último, que fornece portabilidade e segurança. Embora sua relevância, a maioria das aplicações que implementam criptografia simétrica em Smart Cards, são de código proprietário. Este trabalho busca uma alternativa utilizando Java Cards, OpenSC e o cifrador AES, implementando as principais funções de criptografia simétrica em um applet de código aberto. Como resultado, obteve-se um applet open source suportado pelo middleware OpenSC, capaz de realizar as principais funções de criptografia simétrica.Data confidentiality is one of the main pillars of computer security. Among the different ways to reach it, it is worth highlighting the use of secret keys. With them, sensitive information can be encrypted using symmetric encryption algorithms in which the key is shared between the sender and the recipient. The same key performs data encryption and decryption operations. In this context, the biggest problem is securely storing the key. Among the possible ways to store it, we can mention: local database, servers and Smart Cards. Being the focus of this work, the latter, which provides portability and security. Although its relevance, most applications that implement symmetric encryption on Smart Cards, are proprietary code. This work looks for an alternative using Java Cards, OpenSC and the AES cipher, implementing the main functions of symmetric cryptography in an open source applet. As a result, we obtained an open source applet supported by the OpenSC middleware, capable of performing the main symmetric cryptographic functions

Voisin Rational Grazing as a Sustainable Alternative for Livestock Production

Current livestock practices do not meet current real-world social and environmental requirements, pushing farmers away from rural areas and only sustaining high productivity through the overuse of fossil fuels, causing numerous environmental side effects. In this narrative review, we explore how the Voisin Rational Grazing (VRG) system responds to this problem. VRG is an agroecological system based on four principles that maximise pasture growth and ruminant intake, while, at the same time, maintaining system sustainability. It applies a wide range of regenerative agricultural practices, such as the use of multispecies swards combined with agroforestry. Planning allows grazing to take place when pastures reach their optimal resting period, thus promoting vigorous pasture regrowth. Moreover, paddocks are designed in a way that allow animals to have free access to water and shade, improving overall animal welfare. In combination, these practices result in increased soil C uptake and soil health, boost water retention, and protect water quality. VRG may be used to provide ecosystem services that mitigate some of the current global challenges and create opportunities for farmers to apply greener practices and become more resilient. It can be said that VRG practitioners are part of the initiatives that are rethinking modern livestock agriculture. Its main challenges, however, arise from social constraints. More specifically, local incentives and initiatives that encourage farmers to take an interest in the ecological processes involved in livestock farming are still lacking. Little research has been conducted to validate the empirical evidence of VRG benefits on animal performance or to overcome VRG limitation