Modeling the line variations from the wind-wind shock emissions of WR 30a

The study of Wolf-Rayet stars plays an important role in evolutionary theories of massive stars. Among these objects, ~ 20% are known to be in binary systems and can therefore be used for the mass determination of these stars. Most of these systems are not spatially resolved and spectral lines can be used to constrain the orbital parameters. However, part of the emission may originate in the interaction zone between the stellar winds, modifying the line profiles and thus challenging us to use different models to interpret them. In this work, we analyzed the HeII4686\AA + CIV4658\AA blended lines of WR30a (WO4+O5) assuming that part of the emission originate in the wind-wind interaction zone. In fact, this line presents a quiescent base profile, attributed to the WO wind, and a superposed excess, which varies with the orbital phase along the 4.6 day period. Under these assumptions, we were able to fit the excess spectral line profile and central velocity for all phases, except for the longest wavelengths, where a spectral line with constant velocity seems to be present. The fit parameters provide the eccentricity and inclination of the binary orbit, from which it is possible to constrain the stellar masses.Comment: accepted for publication in the MNRA

85% efficiency for cw frequency doubling from 1.08 to 0.54 μm

Conversion efficiency of 85% has been achieved in cw second-harmonic generation from 1.08 to 0.54 μm with a potassium titanyl phosphate crystal inside an external ring cavity. An absolute comparison between the experimental data and a simple theory is made and shows good agreement

Irrigation scheduling for furrow-irrigated maize under climate uncertainties in the Thrace plain, Bulgaria

Research Paper: SW - Soil and WaterClimate change creates uncertainties for irrigation management. To cope with them, simulations were performed for the present and scenario-built weather conditions that include a pessimistic scenario of precipitation decrease in the next 25 years. In a former study, the irrigation scheduling simulation model ISAREG was calibrated for two maize varieties: the water stress-resistant hybrid Kn-2L-611 and the water stress-sensitive hybrid H708. Both are subjects of this study, which compares four irrigation scheduling alternatives: (1) refilling the soil reservoir and adopting a management-allowed depletion fraction (MAD) of 0.47; (2) refilling the soil reservoir and adopting MAD ¼ 0.33; (3) partially refilling the soil reservoir and adopting MAD ¼ 0.47; and (4) crop without irrigation. For the very dry year and the present climate all alternative irrigation schedules behave similarly but for the average year, alternatives 1 and 3, allowing a larger soil water depletion with MAD ¼ 0.47, require less water than the alternative with MAD ¼ 0.33. However, analysis of impact on yields using simulations relative to every year during 1970–1992 shows that alternative 2 leads to less impact on yields. The results of simulations were compared with irrigation schedules presently advised in the region and show that the latter do not fully cover crop requirements in dry seasons, when some yield decrease occurs. Simulations for the pessimistic scenario show that all three irrigation scheduling alternatives can easily accommodate the foreseen changes mainly by selecting suitable irrigation dates. The results of simulations do not allow selecting one among the three alternatives as the best irrigation scheduling strategy but are useful for later building an information system for farmers using actual weather data. Relative to the rainfed crop, the results indicate that yield impacts highly increase for the pessimistic scenario, particularly for the water stresssensitive hybrid H708. The results indicate that vulnerability to climate change is higher for non-irrigated crops and that coping with possible rainfall decreases requires adopting less sensitive crop varieties, including when deficit irrigation would be applied for water saving

Educação e as novas tecnologias de informação e comunicação.

Este artigo analisa a importância do sujeito e sua ação comunicacional em um ambiente mediado pelas tecnologias de informação e comunicação (TIC), sob a perspectiva da educomunicação, que leva em consideração a intencionalidade do processo educativo focado na apropriação do conhecimento pelos cidadãos. Considerando a importância da formação profissional de educadores reflexivos e com visão crítica diante do contexto da Sociedade da Informação, considerou-se relevante estudar qual a concepção de educomunicação que norteia a racionalidade de estudantes formandos em Pedagogia, de forma a identificar estratégicas que, sendo adotadas, pudessem favorecer a introdução deste conceito na formação e na prática profissional de futuros educadores.Abracorp 2014

Comunicação digital nas redes de pesquisa.

A missão das instituições de pesquisa, desenvolvimento e inovação tecnológica (PD&I) é a produção de conhecimento e a geração e transferência de informações, conhecimentos e tecnologias para a sociedade. As tecnologias digitais e as demandas impostas pelos ambientes externos exige destas instituições um tipo de comunicação dinâmica, interativa e imbricada aos tempos sociais dos diversos atores com os quais se relacionam. Neste sentido, as redes de pesquisa interinstitucionais, cujos pilares conceituais são a autonomia, a interdependência de recursos e as ações colaborativas, caracterizam-se como canais que favorecem a interação e o intercâmbio de esforços, ampliando as chances destas instituições obterem resultados mais sistêmicos e integrados.ABRAPCORP 2012