A Self-Occulting Accretion Disk in the SW Sex Star DW UMa

We present the ultraviolet spectrum of the SW Sex star and nova-like variable DW UMa in an optical low state, as observed with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope (HST). The data are well described by a synthetic white dwarf (WD) spectrum with T_eff = 46,000 +/- 1000 K, log g = 7.60 +/- 0.15, v*sin(i) = 370 +/- 100 km/s and Z/Z_solar = 0.47 +/- 0.15. For this combination of T_eff and log g, WD models predict M_WD = 0.48 +/- 0.06 M_solar and R_WD = (1.27 +/- 0.18) * 10^9 cm. Combining the radius estimate with the normalization of the spectral fit, we obtain a distance estimate of d = 830 +/-150 pc. During our observations, DW UMa was approximately 3 magnitudes fainter in V than in the high state. A comparison of our low-state HST spectrum to a high-state spectrum obtained with the International Ultraviolet Explorer shows that the former is much bluer and has a higher continuum level shortward of 1450 A. Since DW UMa is an eclipsing system, this suggests that an optically thick accretion disk rim blocks our view of the WD primary in the high state. If self-occulting accretion disks are common among the SW Sex stars, we can account for (i) the preference for high-inclination systems within the class and (ii) their V-shaped continuum eclipses. Moreover, even though the emission lines produced by a self-obscured disk are generally still double-peaked, they are weaker and narrower than those produced by an unobscured disk. This may allow a secondary line emission mechanism to dominate and produce the single-peaked, optical lines that are a distinguishing characteristic of the SW Sex stars.Comment: 9 pages, including 2 figures; accepted for publication in Astrophysical Journal Letters; New version matches version in press (footnote added to discussion section; figures now use color

Generation of photons from vacuum in cavity via time-modulation of a qubit invisible to the field

We propose a scheme for generation of photons from vacuum due to time-modulation of a quantum system coupled indirectly to the cavity field through some ancilla quantum subsystem. We consider the simplest case when the modulation is applied to an artificial 2-level atom (we call t-qubit), while the ancilla is a stationary qubit coupled via the dipole interaction both to the cavity and t-qubit. We find that tripartite entangled states with a small number of photons can be generated from the system ground state under resonant modulations, even when the t-qubit is far detuned from both the ancilla and the cavity, provided its bare and modulation frequencies are properly adjusted as function of other system parameters. We attest our approximate analytic results by numeric simulations and show that photon generation from vacuum persists in the presence of common dissipation mechanisms

Avaliação do efeito da exposição à nanofibra de celulose em invertebrados aquáticos.

Resumo: As nanofibras de celulose mostram uso promissor na indústria de alimentos. Apesar da esperada inocuidade, é necessário avaliar seus possiveis efeitos adversos decorrentes do seu despejo em corpos de água. Avaliaram-se parametros toxicológicos decorrentes da exposição às nanofibras de celulose nos microcrustáceos Daphnia similis e Artemia salina. A nanofibra de celulose não ocasionaria um risco apreciável para organismos zooplanctônicos já que a concentração de efeito não observado (CENO), segundo os parâmetros avaliados, é superior a 100 mg L-1

Modelos de regressão para determinar a estabilização da variabilidade de dados de energia metabolizábel em aves.

O objetivo do presente foi demonstrar o uso do modelo de platô com resposta linear como ferramenta para a tomada de decisão em experimentos biológicos. Foram utilizados dados de um experimento conduzido na Embrapa Suínos e Aves Concórdia/SC, cujo objetivo era determinar o tempo mínimo de coleta total de excretas para determinação da energia metabolizável com pintos de corte. A avaliação dos dados foi baseada no coeficiente de variação (como medida de variabilidade) em função do tempo de coleta, ajustando-se um modelo de platô com resposta linear, de forma que em certo tempo de coleta ocorreria a estabilização da variabilidade dos dados. Esse modelo permitiu identificar e recomendar que quatro dias de coleta total de excretas já seriam suficientes para estabilizar o coeficiente de variação da energia metabolizável aparente

Uso da metodologia de coleta total de excretas na determinação da energia metabolizável em rações para frangos de corte ajustadas ou não quanto aos níveis de vitaminas e minerais.

Avaliou-se neste estudo a influência dos teores de vitaminas e microminerais da ração-teste na determinação dos valores de energia metabolizável aparente (EMA) e energia metabolizável aparente corrigida pelo nitrogênio retido (EMAn) do farelo de soja. Foram comparadas rações-teste ajustadas ou não para as quantidades de cloreto de colina e premix de vitaminas e microminerais em relação à ração-referência. Adotou-se o método tradicional de coleta total de excretas utilizando-se 360 pintos de corte machos e fêmeas da linhagem Ross de 15 a 23 dias de idade, alojados em baterias metálicas com bandejas coletoras de excretas. As aves foram distribuídas em esquema de blocos casualizados, de acordo com o andar das baterias, com dois tratamentos e 12 repetições de dez aves (cinco machos e cinco fêmeas). Em um tratamento, efetuou-se a substituição de 40% da ração-referência por farelo de soja, enquanto no outro, além dessa substituição, ajustaram-se as quantidades de cloreto de colina e dos premixes de vitaminas e microminerais com base na ração-referência. Os valores médios e os respectivos erros-padrão para EMA e EMAn (kcal/kg) do farelo de soja, com base na matéria natural, foram 2.462%29,62 e 2.269"'25,80 para ração ajustada e 2.353"'26,18 e 2.191"'23,88 para ração não ajustada. O ajuste das quantidades de cloreto de colina e do premix de vitaminas e microminerais na ração-teste propiciou maiores valores de EMA e EMAn do farelo de soja em relação à ração não-ajustada. É importante ajustar as quantidades de vitaminas e microminerais nas rações-teste em experimentos visando determinar a energia metabolizável de ingredientes para aves

Photodetector with integrated optical thin film filters

This paper reports on optical filters based on a-SiC:H tandem pi'n/pin heterostructures. The spectral sensitivity is analyzed. Steady state optical bias with different wavelengths are applied from each front and back sides and the photocurrent is measured. Results show that it is possible to control the sensitivity of the device and to tune a specific wavelength range by combining radiations with complementary light penetration depths. The transfer characteristics effects due to changes in the front and back optical bias wavelength are discussed. Depending on the wavelength of the external background and irradiation side, the device acts either as a short- or a long-pass band filter or as a band-stop filter. The output waveform presents a nonlinear amplitude-dependent response to the wavelengths of the input channels

Fortalezas del carácter y autorregulación emocional en trabajadores brasileños

Character strengths and emotion self-regulation are relevant psychological resources to help workers cope with current demands in the workplace. The present investigation aimed to test the association with and the predictive power of the character strengths regarding emotion self-regulation. A total of 203 participants aged 18 to 68 years answered the sociodemographic questionnaire, Character Strength Scale – Brief (CSS-Brief), and the Emotion Self-Regulation Scale – Adult (ESRS-AD). The findings indicated weak to strong associations between the CSS-Brief and ESRS-AD factors. The intrapersonal strength and the intellectual and interpersonal strengths predicted the emotion self-regulation strategies likely to be adopted by the workers. The gathered evidence suggested significant differences in the ESRS-AD and CSS-Brief regarding the participants’ sociodemographic features. These results have occurred regardless of the workers’ hierarchical level and job department.Las fortalezas del carácter y la autorregulación de las emociones son recursos psicológicos relevantes para ayudar a los trabajadores a hacer frente a las demandas actuales en trabajo. La presente investigación tuvo como objetivo probar la asociación y el poder predictivo de las fortalezas del carácter con respecto a la autorregulación emocional. Un total de 203 participantes con edades entre 18 y 68 años respondieron el cuestionario sociodemográfico, la Escala de Fortaleza del Carácter - Breve (EFC-Breve) y la Escala de Autorregulación Emocional - Adulto (EARE-AD). Los resultados indicaron asociaciones de débiles a fuertes entre los factores CSS-Brief y ESRS-AD. La fortaleza intrapersonal y las fortalezas intelectuales e interpersonales predijeron las estrategias de autorregulación emocional susceptibles de ser adoptadas por los trabajadores. La evidencia recopilada sugirió diferencias significativas en ESRS-AD y CSS-Brief con respecto a las características sociodemográficas de los participantes. Estos resultados se han producido independientemente del nivel jerárquico y del departamento de trabajo de los trabajadores

Fortalezas del carácter y autorregulación emocional en trabajadores brasileños

Character strengths and emotion self-regulation are relevant psychological resources to help workers cope with current demands in the workplace. The present investigation aimed to test the association with and the predictive power of the character strengths regarding emotion self-regulation. A total of 203 participants aged 18 to 68 years answered the sociodemographic questionnaire, Character Strength Scale –Brief (CSS-Brief), and the Emotion Self-Regulation Scale –Adult (ESRS-AD). The findings indicated weak to strong associations between the CSS-Brief and ESRS-AD factors. The intrapersonal strength and the intellectual and interpersonal strengths predicted the emotion self-regulation strategies likely to be adopted by the workers. The gathered evidence suggested significant differences in the ESRS-AD and CSS-Brief regarding the participants’ sociodemographic features. These results have occurred regardless of the workers’ hierarchical level and job department.Las fortalezas del carácter y la autorregulación de las emociones son recursos psicológicos relevantes para ayudar a los trabajadores a hacer frente a las demandas actuales en trabajo. La presente investigación tuvo como objetivo probar la asociación y el poder predictivo de las fortalezas del carácter con respecto a la autorregulación emocional. Un total de 203 participantes con edades entre 18 y 68 años respondieron el cuestionario sociodemográfico, la Escala de Fortaleza del Carácter -Breve (EFC-Breve) y la Escala de Autorregulación Emocional -Adulto (EARE-AD). Los resultados indicaron asociaciones de débiles a fuertes entre los factores CSS-Brief y ESRS-AD. La fortaleza intrapersonal y las fortalezas intelectuales e interpersonales predijeron las estrategias de autorregulación emocional susceptibles de ser adoptadas por los trabajadores. La evidencia recopilada sugirió diferencias significativas en ESRS-AD y CSS-Brief con respecto a las características sociodemográficas de los participantes. Estos resultados se han producido independientemente del nivel jerárquico y del departamento de trabajo de los trabajadore

Uptake and transfer of a Bt toxin by a lepidoptera to Its eggs and effects on Its offspring.

Research on non-target effects of transgenic crop plants has focused primarily on bitrophic, tritrophic and indirect effects of entomotoxins from Bacillus thuringiensis, but little work has considered intergenerational transfer of Cry proteins. This work reports a lepidopteran (Chlosyne lacinia) taking up a Bt entomotoxin when exposed to sublethal or low concentrations, transferring the entomotoxin to eggs, and having adverse effects on the first filial generation (F1) offspring. Two bioassays were conducted using a sublethal concentration of toxin (100.0 ng/ml Cry1Ac) for adults and a concentration equal to the LC10 (2.0 ng/ml Cry1Ac) for larvae. Cry1Ac is the most common entomotoxin expressed in Bt cotton in Brazil. In the adult diet bioassay there was no adverse effect on the parental generation (P0) adults, but the F1 larvae had higher mortality and longer development time compared to F1 larvae of parents that did not ingest Cry1Ac. For the 3rd instar larvae, there was no measurable effect on the P0 larvae, pupae and adults, but the F1 larvae had higher mortality and longer development time. Using chemiluminescent Western Blot, Cry1Ac was detected in F1 eggs laid by P0 butterflies from both bioassays. Our study indicates that, at least for this species and these experimental conditions, a ,65 kDa insecticidal protein can be taken up and transferred to descendants where it can increase mortality and development time