Polarization properties and dispersion relations for spiral resonances of a dielectric rod

Dielectric microcavities based on cylindrical and deformed cylindrical shapes have been employed as resonators for microlasers. Such systems support spiral resonances with finite momentum along the cylinder axis. For such modes the boundary conditions do not separate and simple TM and TE polarization states do not exist. We formulate a theory for the dispersion relations and polarization properties of such resonances for an infinite dielectric rod of arbitrary cross-section and then solve for these quantities for the case of a circular cross-section (cylinder). Useful analytic formulas are obtained using the eikonal (Einstein-Brillouin-Keller) method which are shown to be excellent approximations to the exact results from the wave equation. The major finding is that the polarization of the radiation emitted into the far-field is linear up to a polarization critical angle (PCA) at which it changes to elliptical. The PCA always lies between the Brewster and total-internal-reflection angles for the dielectric, as is shown by an analysis based on the Jones matrices of the spiraling rays.Comment: submitted to JOSA

Cross-Cultural Content Validity of the Autism Program Environment Rating Scale in Sweden

Increasing rates of autism spectrum disorder (ASD) and younger age at diagnosis pose a challenge to preschool intervention systems. In Sweden, most young autistic children receive intervention service in community-based preschool programs, but no tool is yet available to assess the quality of the preschool learning environment. This study adapted the Autism Program Environment Rating Scale Preschool/Elementary to Swedish community context (APERS-P-SE). Following translation and a multistep modification process, independent experts rated the content validity of the adaptation. Findings indicate high cross-cultural validity of the adapted APERS-P-SE. The cultural adaption process of the APERS-P-SE highlights similarities and differences between the American and Swedish preschool systems and their impact on early ASD intervention

Efficacy of chloroquine, sulphadoxine-pyrimethamine and amodiaquine for treatment of uncomplicated Plasmodium falciparum malaria in Kajo Keji county, Sudan.

To provide advice on the rational use of antimalarial drugs, Médecins Sans Frontières conducted a randomized, an open label efficacy study in Kajo Keji, an area of high transmission of malaria in southern Sudan. The efficacy of chloroquine (CQ), sulphadoxine-pyrimethamine (SP) and amodiaquine (AQ) were measured in a 28-day in vivo study, with results corrected by PCR genotyping. Of 2010 children screened, 115 children aged 6-59 months with uncomplicated Plasmodium falciparum malaria were randomized into each group to receive a supervised course of treatment. Of these, 114, 103 and 111 were analysed in the CQ, SP and AQ groups, respectively. The overall parasitological failure rates at day 28 were 93.9% [95% confidence interval (CI) 87.3-97.3] for CQ, 69.9% (95% CI 60.0-78.3) for SP, and 25.2% (95% CI 17.7-34.5) for AQ. These results provide important missing data on antimalarial drug efficacy in southern Sudan. They indicate that none of the drugs could be used in monotherapy and suggest that even in combination with artemisinin, cure rates might not be efficacious enough. We recommend a combination of artemether and lumefantrine as first-line treatment for uncomplicated P. falciparum malaria cases in Kajo Keji county

Temperature dependence of the energy dissipation in dynamic force microscopy

The dissipation of energy in dynamic force microscopy is usually described in terms of an adhesion hysteresis mechanism. This mechanism should become less efficient with increasing temperature. To verify this prediction we have measured topography and dissipation data with dynamic force microscopy in the temperature range from 100 K up to 300 K. We used 3,4,9,10-perylenetetracarboxylic-dianhydride (PTCDA) grown on KBr(001), both materials exhibiting a strong dissipation signal at large frequency shifts. At room temperature, the energy dissipated into the sample (or tip) is 1.9 eV/cycle for PTCDA and 2.7 eV/cycle for KBr, respectively, and is in good agreement with an adhesion hysteresis mechanism. The energy dissipation over the PTCDA surface decreases with increasing temperature yielding a negative temperature coefficient. For the KBr substrate, we find the opposite behaviour: an increase of dissipated energy with increasing temperature. While the negative temperature coefficient in case of PTCDA agrees rather well with the adhesion hysteresis model, the positive slope found for KBr points to a hitherto unknown dissipation mechanism

Efeito da composição da dieta e suplementação com fitase sobre aspectos físicos da tíbia em frangos de corte.

Para avaliar o efeito do farelo de trigo e a suplementação de fitase sobrea resistência óssea, rigidez e flexibilidade da tíbia foram alojados em gaiolas metabólicas 384 pintos de corte, machos da linhagem Cobb, distribuídos em quatro tratamentos em um arranjo fatorial 2x2 em delineamento de blocos casualizados com oito repetições e 12 aves por unidade experimental. Os tratamentos foram: T1 -dieta basal (milho e farelo soja) sem fitase; T2 ?dieta basal com 500 FTU/kg de fitase; T3?20% farelo de trigo, sem fitase; T4 ?20% farelo de trigo, com 500 FTU/kg de fitase. Aos 22 e 32 dias de idade foram abatidas duas aves por unidade experimental para a retirada da tíbia e posterior análise. Aos 22 dias de idade os ossos apresentaram maior rigidez em aves alimentadas com dieta basal com e sem fitase. Maior resistência a quebra e flexibilidade foram encontradas somente para as aves que receberam dieta basal sem fitase. Aos 32 dias de idade as aves que receberam farelo de trigo apresentaram tíbias com maior rigidez que as aves que receberam dieta a base de farelo de soja e milho. To evaluate the effect of wheat meal and phytase supplementation on break strength, flexibility and rigidity of the tibia 384 broiler chicks, Cobb males were housed in metabolic cages and allotted to four treatments in a 2x2 factorial arrangement using a randomized block design with eight replicates of 12 birds per experimental unit. The treatments were: T1 -basal diet (corn and soybean meal without phytase), T2 -basal diet with 500 FTU/kg of phytase), T3 - 20% wheat meal without phytase and T4 - 20% wheat meal with 500 FTU/kg of phytase. At 22 and 32 days of age two birds per experimental unit were slaughtered for the withdrawal of the tibia for subsequent analysis. At 22 days of age, birds fed basal diet with and without phytase showed higher bone stiffness. Greater breaking strength and flexibility were found only for those birds receiving the basal diet without phytate. At 32days of age birds receiving 20% of wheat meal shown greater tibia rigidity than birds fed a corn-soybean meal -based diet

Efeito da inclusão de fitase e farelo de trigo na dieta de frangos de corte sobre a composição química da tíbia.

Para avaliar o efeito da inclusão de fitase e farelo de trigo sobre o teor de cálcio, fósforo, matéria mineral e a relação Ca:P na tíbia de frangos de corte, foram alojadas 384 aves, distribuídas em quatro tratamentos em um arranjo fatorial 2x2 em delineamento de blocos casualizados com oito repetições e 12 aves por unidade experimental. Os tratamentos foram: T1 ? controle negativo (milho e farelo soja) sem fitase; T2 ? controle positivo com 500 FTU/kg de fitase; T3 ? 20% farelo de trigo, sem fitase; T4 ? 20% farelo de trigo, com 500 FTU/kg de fitase. A composição da dieta, independente da presença ou ausência de fitase teve efeito significativo, reduzindo a concentração de fósforo e matéria mineral da tíbia. Para o efeito entre as dietas (com fitase), foi observada diferença significativa para o cálcio, fósforo e matéria mineral, onde a dieta milho e farelo de soja proporcionou maior concentração destas variáveis analisadas em relação a dieta contendo farelo de trigo. To evaluate the effect of inclusion of phytase and wheat bran on calcium, phosphorus, ash and Ca: P ratio in the tibia of broilers, 384 birds were housed, assigned to four treatments in a 2x2 factorial arrangement in randomized block design with eight replicates of 12 birds each. The treatments were: T1 - negative control (corn and soybean meal) without phytase; T2 - positive control with 500 FTU / kg of phytase; T3 - 20% wheat bran, no phytase; T4 - 20% of wheat bran with 500 FTU / kg of phytase. It was found that the diet, independently from the phytase inclusion had a significant effect, reducing the concentration of phosphorus and mineral matter of the tibia. Comparing diets, both with phytase, a significant difference for calcium, phosphorus and mineral matter in the tibia were observed. Diet based on corn and soybean meal provided greater concentration of these parameters

Beagle 2: Mission to Mars — current status

Beagle 2, developed in the UK, was launched on June 2, 2003. It landed on Mars on December 25th, 2003 in Isidis Planitia, a large sedimentary basin. To date, the team is awaiting signals from the Beagle 2 lander. Current status of the mission will be reported