UEFI BIOS Accessibility for the Visually Impaired

People with some kind of disability face a high level of difficulty for everyday tasks because, in many cases, accessibility was not considered necessary when the task or process was designed. An example of this scenario is a computer's BIOS configuration screens, which do not consider the specific needs, such as screen readers, of visually impaired people. This paper proposes the idea that it is possible to make the pre-operating system environment accessible to visually impaired people. We report our work-in-progress in creating a screen reader prototype, accessing audio cards compatible with the High Definition Audio specification in systems running UEFI compliant firmware.Comment: 6 page

Relative phase stability and lattice dynamics of NaNbO3_3 from first-principles calculations

We report total energy calculations for different crystal structures of NaNbO$_3$ over a range of unit cell volumes using the all-electron full-potential (L)APW method. We employed both the local-density approximation (LDA) and the Wu-Cohen form of the generalized gradient approximation (GGA-WC) to test the accuracy of these functionals for the description of the complex structural behavior of NaNbO$_3$. We found that LDA not only underestimates the equilibrium volume of the system but also predicts an incorrect ground state for this oxide. The GGA-WC functional, on the other hand, significantly improves the equilibrium volume and provides relative phase stability in better agreement with experiments. We then use the GGA-WC functional for the calculation of the phonon dispersion curves of cubic NaNbO$_3$ to identify the presence of structural instabilities in the whole Brillouin zone. Finally, we report comparative calculations of structural instabilities as a function of volume in NaNbO$_3$ and KNbO$_3$ to provide insights for the understanding of the structural behavior of K$_{1-x}$Na$_x$NbO$_3$ solid solutions.Comment: Accepted for publication in Physical Review

Quantum signatures in quadratic optomechanics

We analyze quantum effects occurring in optomechanical systems where the coupling between an optical mode and a mechanical mode is quadratic in displacement (membrane-in-the-middle geometry). We show that it is possible to observe quantum effects in these systems without achieving the single-photon strong coupling regime. We find that zero-point energy causes a mechanical frequency shift, and we propose an experimental way to measure it. Further, we show that it is possible to determine the phonon statistics from the cavity transmission, and propose a way to infer the resonator's temperature based on this feature. For completeness, we revisit the case of an isolated system and show that different types of mechanical quantum states can be created, depending on the initial cavity state. In this situation, mechanical motion undergoes collapse and revivals, and we compute the collapse and revival times, as well as the degree of squeezing.Comment: 7 pages, 6 figures, 2nd versio

CCD Photometry of Delta Scuti stars 7 Aql and 8 Aql

As a continuation of the study of the Delta Scuti stars 7 Aql and 8 Aql; new CCD photometric data were acquired in 2007. We present a period analysis on these data that confirm the dominant modes detected in each star in the framework of the STEPHI XII campaign in 2003.Comment: 9 pages, 7 figures, 2 tables; Accepted for publication in Communications in Asteroseismology, Vol 153, 200

Conteúdo de noradrenalina do hipotálamo e tronco-encefálico de ratos inoculados com Trypanosoma Cruzi

Noradrenaline was assayed fluorimetrically in the hypothalamus and brainstem of rats killed 20 and 32 days after inoculation with the Y strain of T. cruzi (300,000 trypomastigotes i.p.). In these animals and their normal controls the right atrial appendages were submitted to the glyoxilic acid fluorescence technique for the demonstration of noradrenergic nerves. The noradrenaline content of the brain-stem and hypothalamus of the infected animals was not significantly different from that of controls. In the atrial appendages, however, an almost complete noradrenergic denervation was observed. This result indicates that the mechanism involved in neuronal lesion in Chagas'disease discriminates between peripheral and central noradrenergic neurons.O conteúdo de noradrenalina do hipotálamo e do tronco encefálico de ratos controle e inoculados com a cepa Y (300.000 tripomastigotas, i.p.) de Trypanosoma cruzi foi medido pela técnica fluorimétrica de Anton e Sayre. Os animais foram sacrificados 20 e 32 dias depois da inoculação. Para avaliação do grau de desnervação simpática do coração dos animais infectados, a aurícula direita foi observada com microscópio de fluorescência após tratamento histoquímieo pela técnica do ácido glioxílico. O conteúdo de noradrenalina do hipotálamo e do tronco encefálico dos animais infectados não diferiu do medido nos animais controle. Contudo, um quase completo desaparecimento das fibras adrenérgicas foi observado no coração dos animais chagásicos, sugerindo que o mechanismo envolvido na lesão discrimina neurônios adrenérgicos centrais e periféricos