The Quest for an Intermediate-Scale Accidental Axion and Further ALPs

The recent detection of the cosmic microwave background polarimeter experiment BICEP2 of tensor fluctuations in the B-mode power spectrum basically excludes all plausible axion models where its decay constant is above $10^{13}$ GeV. Moreover, there are strong theoretical, astrophysical, and cosmological motivations for models involving, in addition to the axion, also axion-like particles (ALPs), with decay constants in the intermediate scale range, between $10^9$ GeV and $10^{13}$ GeV. Here, we present a general analysis of models with an axion and further ALPs and derive bounds on the relative size of the axion and ALP photon (and electron) coupling. We discuss what we can learn from measurements of the axion and ALP photon couplings about the fundamental parameters of the underlying ultraviolet completion of the theory. For the latter we consider extensions of the Standard Model in which the axion and the ALP(s) appear as pseudo Nambu-Goldstone bosons from the breaking of global chiral $U(1)$ (Peccei-Quinn (PQ)) symmetries, occuring accidentally as low energy remnants from exact discrete symmetries. In such models, the axion and the further ALP are protected from disastrous explicit symmetry breaking effects due to Planck-scale suppressed operators. The scenarios considered exploit heavy right handed neutrinos getting their mass via PQ symmetry breaking and thus explain the small mass of the active neutrinos via a seesaw relation between the electroweak and an intermediate PQ symmetry breaking scale. We show some models that can accommodate simultaneously an axion dark matter candidate, an ALP explaining the anomalous transparency of the universe for $\gamma$-rays, and an ALP explaining the recently reported 3.55 keV gamma line from galaxies and clusters of galaxies, if the respective decay constants are of intermediate scale.Comment: 43pp, 4 figures. v2: version accepted for publication in JHE

Actin assembly ruptures the nuclear envelope by prying the lamina away from nuclear pores and nuclear membranes in starfish oocytes.

The nucleus of oocytes (germinal vesicle) is unusually large and its nuclear envelope (NE) is densely packed with nuclear pore complexes (NPCs) stockpiled for embryonic development. We showed that breakdown of this specialized NE is mediated by an Arp2/3-nucleated F-actin 'shell' in starfish oocytes, in contrast to microtubule-driven tearing in mammalian fibroblasts. Here, we address the mechanism of F-actin-driven NE rupture by correlated live-cell, super-resolution and electron microscopy. We show that actin is nucleated within the lamina sprouting filopodia-like spikes towards the nuclear membranes. These F-actin spikes protrude pore-free nuclear membranes, whereas the adjoining membrane stretches accumulate NPCs associated with the still-intact lamina. Packed NPCs sort into a distinct membrane network, while breaks appear in ER-like, pore-free regions. Thereby, we reveal a new function for actin-mediated membrane shaping in nuclear rupture that is likely to have implications in other contexts such as nuclear rupture observed in cancer cells

Analysis of the Scanning Tunneling Microscopy Images of the Charge Density Wave Phase in Quasi-one-dimensional Rb0.3MoO3

The experimental STM images for the CDW phase of the blue bronze RbMoO3 have been successfully explained on the basis of first-principles DFT calculations. Although the density of states near the Fermi level strongly concentrates in two of the three types of Mo atoms Mo-II and Mo-III, the STM measurement mostly probes the contribution of the uppermost O atoms of the surface, associated with the Mo-IO6 octahedra. In addition, it is found that the surface concentration of Rb atoms plays a key role in determining the surface nesting vector and hence the periodicity of the CDW modulation. Significant experimental inhomogeneities of the b* surface component of the wavevector of the modulation, probed by STM, are reported. The calculated changes in the surface nesting vector are consistent with the observed experimental inhomogeneities.Comment: 4 pages 5 Figure

Quality in management accounting: approach by activities in large companies

This study intends to contribute to the knowledge about the approach by activities, a management accounting method that promotes the quality of information. As specific objectives we have identified the following: to analyze the knowledge rate regarding the approach by activities, and identify whether there is a link between it and the financial officers’ characteristics; to analyze the utilization rate of the approach by activities, and the factors conditioning it; to analyze whether there is a link between a company’s features, and the use of the approach by activities. The data collection method used was the application of a survey to the financial officers of the largest Portuguese companies, which yielded 61 valid responses. The results found allowed us to conclude the following: the Time Driven Activity Based Costing is very little known and used in Portugal; there is a link between the knowledge of the approach by activities and the financial officers’ gender, age and educational background; there is a link between the use of the approach by activities and two company features: the legal form and the capital holding.info:eu-repo/semantics/acceptedVersio

Síndrome de Stevens-Johnson. Apresentação de Caso Clínico

Introdução: A Síndrome de Stevens-Johnson (SSJ) é uma doença mucocutânea rara e potencialmente fatal, mais frequente no sexo masculino, cuja incidência aumenta com a idade e em determinados grupos de risco. A SSJ e a Necrólise Tóxica Epidérmica (NET) são duas entidades da mesma doença, com severidade diferente. A etiologia não é clara, mas pensa-se que se deva maioritariamente a reacções adversas a fármacos. Caso clínico: Um jovem de 17 anos de idade, sem antecedentes pessoais relevantes, foi observado no Serviço de Urgência por surgimento de lesões maculopapulares, com 3 dias de evolução, dispersas pela face, cavidade oral, tronco e extremidades, com prostração e taquicardia. Foi internado com o diagnóstico de SSJ. Discussão e Conclusões: O SSJ e a NET têm grande morbilidade e considerável mortalidade. O rápido reconhecimento desta identidade, com a remoção do fármaco desencadeador é essencial. A perda da função de barreira da pele, com a consequente alteração da homeostasia, implica muitas vezes a manutenção da terapêutica de suporte em Unidades de Cuidados Intensivos ou de Queimados.info:eu-repo/semantics/publishedVersio