Modelling photospheric magnetoconvection

The increasing power of computers makes it possible to model the nonlinear interaction between magnetic fields and convection at the surfaces of solar-type stars in ever greater detail. We present the results of idealized numerical experiments on two-dimensional magnetoconvection in a fully compressible perfect gas. We first vary the aspect ratio lambda of the computational box and show that the system runs through a sequence of convective patterns, and that it is only for a sufficiently wide box (lambda>=6) that the flow becomes insensitive to further increases in lambda. Next, setting lambda=6, we decrease the field strength from a value strong enough to halt convection and find transitions to small-scale steady convection, next to spatially modulated oscillations (first periodic, then chaotic) and then to a new regime of flux separation, with regions of strong field (where convection is almost completely suppressed) separated by broad convective plumes. We also explore the effects of altering the boundary conditions and show that this sequence of transitions is robust. Finally, we relate these model calculations to recent high-resolution observations of solar magnetoconvection, in plage regions as well as in light bridges and the umbrae of sunspots

Maternal smoking during pregnancy, other prenatal and perinatal factors, and the risk of Legg-Calvé-Perthes disease

OBJECTIVE. The causes of Legg-Calvé-Perthes disease are largely unknown, but this pediatric disease seems to result from interruption of the blood supply to the proximal femur and is considered a vascular disease. Because maternal smoking during pregnancy influences fetal development and is associated with cardiovascular diseases in offspring, we hypothesized that this exposure is a risk for Legg-Calvé- Perthes disease and also investigated other markers of impaired fetal development and early-life exposures. MATERIALS AND METHODS. The Swedish Inpatient Register identified 852 individuals with a diagnosis of Legg-Calvé-Perthes disease from 1983 to 2005, individually matched by year of birth, age, sex, and region of residence with 4432 randomly selected control subjects. Linkage with the Swedish Medical Birth Register provided information on prenatal factors, including maternal smoking. Conditional logistic regression examined associations of maternal smoking during pregnancy and the other measures with the risk of Legg-Calvé-Perthes disease in offspring, adjusted for socioeconomic index and other potential confounding factors. RESULTS. Maternal smoking during pregnancy was associated with an increased Legg-Calvé-Perthes disease risk, and heavy smoking was associated with a risk increase of almost 100%. Very low birth weight and cesarean section were independently associated with ̃240% and 36% increases in the risk of Legg-Calvé-Perthes disease, respectively. CONCLUSION. Maternal smoking during pregnancy and other factors indicated by impaired fetal development may be associated with an increased risk of Legg-Calvé- Perthes disease

Didactic Software for Autistic Children

In this paper we describe the aims and requirements of a project devoted to designing and developing Open Source didactic Software (SW) for children in the autism disorder spectrum, conforming to the Applied Behaviour Analysis (ABA) learning technique. In this context, participatory design with therapists and child?s parents is necessary to ensure a usable product that responds to these children?s special needs and respects education principles and constraints of the ABA methodology

Microwaves affect thermoregulatory behavior in rats

Rats, with their fur clipped, pressed a lever to turn on an infrared lamp while in a cold chamber. When 2450 Megahertz continuous wave microwaves were presented for 15 minutes, the rate of turning on the infrared lamp decreased as a function of the microwave power density, which ranged between 5 MW/cm/sup 2/ and 20 MW/cm/sup 2/. This result indicates that behaviorally significant levels of heating occur at exposure durations and intensities that do not produce reliable changes in either colonic temperature or other behavioral measures. Further study of how microwaves affect thermoregulatory behavior may help us understand phenomena such as reported non-thermal behavioral effects of microwaves

The detection of Gravitational Waves

This chapter is concerned with the question: how do gravitational waves (GWs) interact with their detectors? It is intended to be a theory review of the fundamental concepts involved in interferometric and acoustic (Weber bar) GW antennas. In particular, the type of signal the GW deposits in the detector in each case will be assessed, as well as its intensity and deconvolution. Brief reference will also be made to detector sensitivity characterisation, including very summary data on current state of the art GW detectors.Comment: 33 pages, 12 figures, LaTeX2e, Springer style files --included. For Proceedings of the ERE-2001 Conference (Madrid, September 2001

AVALIAÇÃO HISTOPATOLÓGICA, HORMONAL E BACTERIOLÓGICA DA PIOMETRA NA CADELA

O presente estudo teve como objetivo analisar os níveis hormonais, as alterações histopatológicas e os agentes etiológicos encontrados na piometra aberta e fechada em cadelas. Foram colhidas 30 amostras de fêmeas ovariohisterectomizadas em clínicas veterinárias da cidade de Curitiba, no Estado do Paraná, no período de outubro de 2002 a maio de 2003. Procedeu-se a exames bacteriológicos, análises histopatológicas dos cornos uterinos e dosagem hormonal da progesterona e do estradiol pela quimioluminescência. A bactéria isolada em maior porcentagem (36%) foi a Escherichia coli, e a alteração histológica de hiperplasia cística endometrial encontrada variou do grau I ao grau III. A proporção entre a progesterona e estradiol teve uma variação significativa nos dois tipos de piometra, porém não foi possível relacionar o agente etiológico, o tipo de lesão e a dosagem hormonal com o tipo de piometra, aberta ou fechada. Histopathological, hormonal, bacterial evaluation in the bitch pyometra Abstract The aim of the present study was to carry out an evaluation of the hormone levels, the histological changes and the etiological agents found in the open and closed pyometra. The uterine horns were collected from 30 bitches subjected to ovariectomy in different veterinary clinics from Curitiba, State of Parana, during the period of October 2002 to May, 2003. Bacteriological cultures, histological analysis and assays of progesterone and estradiol by the chemoluminescent method were performed. Escherichia coli showed to be the most frequent (36%) of the isolated bateria. It has been found the histological analysis that cystic endometrial hyperplasia varied from type I to type III. The progesterone/ estradiol ratio showed a significant variation in regard to the two types of piometra. However, it was not possible to corrrelate the etiological agent, the lesion and the hormonal levels with the open or closed pyometra

Edge magnetoplasmons in periodically modulated structures

We present a microscopic treatment of edge magnetoplasmons (EMP's) within the random-phase approximation for strong magnetic fields, low temperatures, and filling factor $\nu =1(2)$, when a weak short-period superlattice potential is imposed along the Hall bar. The modulation potential modifies both the spatial structure and the dispersion relation of the fundamental EMP and leads to the appearance of a novel gapless mode of the fundamental EMP. For sufficiently weak modulation strengths the phase velocity of this novel mode is almost the same as the group velocity of the edge states but it should be quite smaller for stronger modulation. We discuss in detail the spatial structure of the charge density of the renormalized and the novel fundamental EMP's.Comment: 8 pages, 4 figure