Spontaneous parity violation and minimal Higgs models

In this paper we present a model for the spontaneous breaking of parity with two Higgs doublets and two neutral Higgs singlets which are even and odd under D-parity. The condition $v_R >>v_L$ can be satisfied without introducing bidoublets and it is induced by the breaking of D-parity through the vacuum expectation value of the odd Higgs singlet. Examples of left-right symmetric and mirror fermions models in grand unified theories are presented.Comment: Revised version. Accepted in Eur. Phys. Journal

Comportamento de próteses de anca de baixa rigidez material: a interface osso-implante

O presente trabalho refere-se aos resultados de um estudo do comportamento de um componente femoral para prótese de anca fabricado em PEEK com reforço aleatório de fibra de carbono, colocado por press-fit, usando como modelo animal a ovelha. Aqui somente se relatam os resultados relativos ao exame histológico de secções de osso de dois animais, após três meses de implantação. Os resultados enfatizam o carácter determinante das características mecânicas do biomaterial e da adaptação da geometria do implante ao canal femoral para a regulação dos eventos biológicos na interface osso-implante

Estudo animal de próteses de anca em compósito PEEK-Carbono

O estudo aqui apresentado teve como objectivo a avaliação de um compósito de PEEK reforçado em 30% com fibra de carbono curta, distribuída aleatoriamente, como material com potencial para aplicação ortopédica. Para o efeito, foram concebidos e fabricados protótipos de próteses de anca do tipo press-fit, baseadas em imagens radiográficas e implantadas em seis ovelhas. Dois dos animais foram sacrificados três meses após a cirurgia e os resultados do exame radiográfico, da necrópsia e exame histológico são apresentados e discutidos

Universality and scaling study of the critical behavior of the two-dimensional Blume-Capel model in short-time dynamics

In this paper we study the short-time behavior of the Blume-Capel model at the tricritical point as well as along the second order critical line. Dynamic and static exponents are estimated by exploring scaling relations for the magnetization and its moments at early stage of the dynamic evolution. Our estimates for the dynamic exponents, at the tricritical point, are $z= 2.215(2)$ and $\theta= -0.53(2)$.Comment: 12 pages, 9 figure

Four millennia of Iberian biomolecular prehistory illustrate the impact of prehistoric migrations at the far end of Eurasia

Population genomic studies of ancient human remains have shown how modern-day European population structure has been shaped by a number of prehistoric migrations. The Neolithization of Europe has been associated with large-scale migrations from Anatolia, which was followed by migrations of herders from the Pontic steppe at the onset of the Bronze Age. Southwestern Europe was one of the last parts of the continent reached by these migrations, and modern-day populations from this region show intriguing similarities to the initial Neolithic migrants. Partly due to climatic conditions that are unfavorable for DNA preservation, regional studies on the Mediterranean remain challenging. Here, we present genome-wide sequence data from 13 individuals combined with stable isotope analysis from the north and south of Iberia covering a four-millennial temporal transect (7, 500–3, 500 BP). Early Iberian farmers and Early Central European farmers exhibit significant genetic differences, suggesting two independent fronts of the Neolithic expansion. The first Neolithic migrants that arrived in Iberia had low levels of genetic diversity, potentially reflecting a small number of individuals; this diversity gradually increased over time from mixing with local hunter-gatherers and potential population expansion. The impact of post-Neolithic migrations on Iberia was much smaller than for the rest of the continent, showing little external influence from the Neolithic to the Bronze Age. Paleodietary reconstruction shows that these populations have a remarkable degree of dietary homogeneity across space and time, suggesting a strong reliance on terrestrial food resources despite changing culture and genetic make-up