Os dois corpos do rei na Inglaterra Anglo-Saxônica

Desde o princípio do período medieval, uma das figuras de destaque na sociedade é o rei. Sua presença é fundamental para o equilíbrio social, uma vez que ele não é apenas o governante de seu povo, mas também representa os poderes divinos manifestados através de sua pessoa. Assim, iremos abordar de que maneira esta figura dupla do rei é representada através da literatura do período anglo-saxão da história medieval inglesa, não como mero símbolo heróico em guerra, mas sim como o guardião de seu povo e mantenedor da paz.Since the beginnings of the medieval period, one of the most prominent characters in this kind of society is the king. His presence is extremely important to the social harmony, hence the king is not only the ruler of the people, but also represents the godly powers that manifest through him. So, we will show how this king dual-figure is represented in Anglo-Saxon literature, not as just a heroic symbol of war, but as the guardian of his folk e keeper of peace

A window into a public programme for prevention of mother-to-child transmission of HIV: evidence from a prospective clinical trial

Objectives. To evaluate efficacy of the antenatal, intrapartum and postnatal antiretroviral components of a public service prevention of mother-to-child (PMTCT) programme in infants.Design. Analysis of prospectively collected screening data of demographic and MTCT-related interventions and HIV infection status of infants identified through HIV-specific DNA polymerase chain reaction.Setting. Tygerberg Children’s Hospital, Western Cape, South Africa.Subjects. HIV-infected women and their infants identified through participation in a public service PMTCT programme were referred for possible participation in a prospective study of isoniazid prophylaxis.Interventions. Key components of the programme include voluntary counselling and testing, administration of zidovudine to the mother from between 28 and 34 weeks’ gestation and to the newborn infant for the firstweek, single-dose nevirapine to the mother in labour and to the newborn shortly after birth, and free formula for 6 months.Main outcome measures. Number and percentage of HIV-infected infants and extent of exposure to antenatal, intrapartum and postnatal antiretrovirals.Results. Of 656 infants with a median age of 12.6 weeks, screened between 1 April 2005 through May 2006, 39 were HIV-infected, giving a transmission rate of 5.9% (95% confidence interval (CI) 4.4 - 8.0%). Antenatal prophylaxis was significantly associated with reduced transmission (odds ratio (OR) 0.43 (95% CI 0.21 - 0.94)) as opposed to intrapartum and postpartum components (p=0.85 and p=0.84, respectively). In multivariable analysis the antenatal component remained significant (OR=0.40 (95% CI 0.19 - 0.90)).Conclusions. The antenatal phase is the most important antiretroviral component of the PMTCT programme, allowing most opportunity for intervention

Approximate sampling formulae for general finite-alleles models of mutation

Many applications in genetic analyses utilize sampling distributions, which describe the probability of observing a sample of DNA sequences randomly drawn from a population. In the one-locus case with special models of mutation such as the infinite-alleles model or the finite-alleles parent-independent mutation model, closed-form sampling distributions under the coalescent have been known for many decades. However, no exact formula is currently known for more general models of mutation that are of biological interest. In this paper, models with finitely-many alleles are considered, and an urn construction related to the coalescent is used to derive approximate closed-form sampling formulas for an arbitrary irreducible recurrent mutation model or for a reversible recurrent mutation model, depending on whether the number of distinct observed allele types is at most three or four, respectively. It is demonstrated empirically that the formulas derived here are highly accurate when the per-base mutation rate is low, which holds for many biological organisms.Comment: 22 pages, 1 figur

A convergent algorithm for the hybrid problem of reconstructing conductivity from minimal interior data

We consider the hybrid problem of reconstructing the isotropic electric conductivity of a body $\Omega$ from interior Current Density Imaging data obtainable using MRI measurements. We only require knowledge of the magnitude $|J|$ of one current generated by a given voltage $f$ on the boundary $\partial\Omega$. As previously shown, the corresponding voltage potential u in $\Omega$ is a minimizer of the weighted least gradient problem $$u=\hbox{argmin} \{\int_{\Omega}a(x)|\nabla u|: u \in H^{1}(\Omega), \ \ u|_{\partial \Omega}=f\},$$ with $a(x)= |J(x)|$. In this paper we present an alternating split Bregman algorithm for treating such least gradient problems, for $a\in L^2(\Omega)$ non-negative and $f\in H^{1/2}(\partial \Omega)$. We give a detailed convergence proof by focusing to a large extent on the dual problem. This leads naturally to the alternating split Bregman algorithm. The dual problem also turns out to yield a novel method to recover the full vector field $J$ from knowledge of its magnitude, and of the voltage $f$ on the boundary. We then present several numerical experiments that illustrate the convergence behavior of the proposed algorithm

An integral equation method for the inverse conductivity problem

We present an image reconstruction algorithm for the Inverse Conductivity Problem based on reformulating the problem in terms of integral equations. We use as data the values of injected electric currents and of the corresponding induced boundary potentials, as well as the boundary values of the electrical conductivity. We have used a priori information to find a regularized conductivity distribution by first solving a Fredholm integral equation of the second kind for the Laplacian of the potential, and then by solving a first order partial differential equation for the regularized conductivity itself. Many of the calculations involved in the method can be achieved analytically using the eigenfunctions of an integral operator defined in the paper.Comment: 15 pages, 8 figure

Sexual selection on protamine and transition nuclear protein expression in mouse species

Post-copulatory sexual selection in the form of sperm competition is known to influence the evolution of male reproductive proteins in mammals. The relationship between sperm competition and regulatory evolution, however, remains to be explored. Protamines and transition nuclear proteins are involved in the condensation of sperm chromatin and are expected to affect the shape of the sperm head. A hydrodynamically efficient head allows for fast swimming velocity and, therefore, more competitive sperm. Previous comparative studies in rodents have documented a significant association between the level of sperm competition (as measured by relative testes mass) and DNA sequence evolution in both the coding and promoter sequences of protamine 2. Here,we investigate the influence of sexual selection on protamine and transition nuclear protein mRNA expression in the testes of eight mouse species that differ widely in levels of sperm competition.We also examined the relationship between relative gene expression levels and sperm head shape, assessed using geometric morphometrics. We found that species with higher levels of sperm competition express less protamine 2 in relation to protamine 1 and transition nuclear proteins. Moreover, therewas a significant association between relative protamine 2 expression and sperm head shape. Reduction in the relative abundance of protamine 2 may increase the competitive ability of sperm in mice, possibly by affecting sperm head shape. Changes in gene regulatory sequences thus seem to be the basis of the evolutionary response to sexual selection in these proteins. © 2014 The Author(s) Published by the Royal Society. All rights reserved.This work was supported by the Spanish Ministry of Economy and Competitiveness (grant no. CGL2011-26341)Peer Reviewe

Full-wave invisibility of active devices at all frequencies

There has recently been considerable interest in the possibility, both theoretical and practical, of invisibility (or "cloaking") from observation by electromagnetic (EM) waves. Here, we prove invisibility, with respect to solutions of the Helmholtz and Maxwell's equations, for several constructions of cloaking devices. Previous results have either been on the level of ray tracing [Le,PSS] or at zero frequency [GLU2,GLU3], but recent numerical [CPSSP] and experimental [SMJCPSS] work has provided evidence for invisibility at frequency $k\ne 0$. We give two basic constructions for cloaking a region $D$ contained in a domain $\Omega$ from measurements of Cauchy data of waves at \p \Omega; we pay particular attention to cloaking not just a passive object, but an active device within $D$, interpreted as a collection of sources and sinks or an internal current.Comment: Final revision; to appear in Commun. in Math. Physic

Inverse problems with partial data for a magnetic Schr\"odinger operator in an infinite slab and on a bounded domain

In this paper we study inverse boundary value problems with partial data for the magnetic Schr\"odinger operator. In the case of an infinite slab in $R^n$, $n\ge 3$, we establish that the magnetic field and the electric potential can be determined uniquely, when the Dirichlet and Neumann data are given either on the different boundary hyperplanes of the slab or on the same hyperplane. This is a generalization of the results of [41], obtained for the Schr\"odinger operator without magnetic potentials. In the case of a bounded domain in $R^n$, $n\ge 3$, extending the results of [2], we show the unique determination of the magnetic field and electric potential from the Dirichlet and Neumann data, given on two arbitrary open subsets of the boundary, provided that the magnetic and electric potentials are known in a neighborhood of the boundary. Generalizing the results of [31], we also obtain uniqueness results for the magnetic Schr\"odinger operator, when the Dirichlet and Neumann data are known on the same part of the boundary, assuming that the inaccessible part of the boundary is a part of a hyperplane