Chemical evolution of the bulge of M31: predictions about abundance ratios

We aim at reproducing the chemical evolution of the bulge of M31 by means of a detailed chemical evolution model, including radial gas flows coming from the disk. We study the impact of the initial mass function, the star formation rate and the time scale for bulge formation on the metallicity distribution function of stars. We compute several models of chemical evolution using the metallicity distribution of dwarf stars as an observational constraint for the bulge of M31. Then, by means of the model which best reproduces the metallicity distribution function, we predict the [X/Fe] vs. [Fe/H] relations for several chemical elements (O, Mg, Si, Ca, C, N). Our best model for the bulge of M31 is obtained by means of a robust statistical method and assumes a Salpeter initial mass function, a Schmidt-Kennicutt law for star formation with an exponent k=1.5, an efficiency of star formation of $\sim 15\pm 0.27\, Gyr^{-1}$, and an infall timescale of $\sim 0.10\pm 0.03$Gyr. Our results suggest that the bulge of M31 formed very quickly by means of an intense star formation rate and an initial mass function flatter than in the solar vicinity but similar to that inferred for the Milky Way bulge. The [$\alpha$/Fe] ratios in the stars of the bulge of M31 should be high for most of the [Fe/H] range, as is observed in the Milky Way bulge. These predictions await future data to be proven.Comment: Accepted for publication by MNRA

Gate stability of GaN-Based HEMTs with P-Type Gate

status: publishe

Efeito da adição de óleo na dieta de frangos sobre características físicas da ração.

No presente trabalho foi avaliado o efeito de níveis crescentes de adição de óleo de soja em dietas de frangos de corte sobre as características físicas da ração. Os trata mentos foram compostos por cinco níveis de inclusão de óleo:T1 ?1,74%; T2 ?2,87%; T3?4,01%; T4?5,15%; T5?6,28%.Estas dietas foram submetidas à peletização em equipamento CPM. Antes e após a produção foram coletadas cinco amostras por tratamento e analisadas em relação à características físicas. O delineamento experimental foi inteiramente ao acaso com cinco tratamentos e cinco repetições. Os dados foram submetidos à análise de variância e as médias foram comparadas pelo este t-Student, ao nível de 5%. Foram testados contrastes polinomiais e geradas as equações de regressão. Considerando os níveis de óleo como bloco, foram realizadas as comparações entre as rações fareladas e peletizadas. A peletização reduziu 23% na densidade da ração em relação à farelada. A peletização da dieta aumentou a umidade da ração, reduziu a densidade e diminui o ângulo de repouso. A adição de óleo reduziu o comprimento do pelete, reduziu a densidade da ração farelada, peletizada e da unidade do pelete e aumentou o ângulo de repouso tanto das dietas fareladas quanto peletizadas. This study evaluated the effect of increasing soybean oil levels on feed physical characteristics in broiler diets. The treatments consisted of five oil levels; T1 ?1.74 %, T2 ?2.87 %; T3 ?4.01%, T4 ?5.15%; T5 ?6.28 %. These diets were pelletized with CPM equipment. Before and after pelleting five samples per treatment were collected. Samples were cooled and analyzed for hardness and durability of the pellet and the percentage of fines. The experimental design was completely randomized with five treatments and five replicates. Data were submitted to analysis of variance and means were compared by t-Student Test at 5% level. Polynomial contrasts were also tested and generated regression equations. Assuming oil levels as block, it were performed comparisons between mash and pelleted diets. The pelleting reduced 23% in the feed density comparing to mash. Pelleting diets resulted in an increased of feed moisture, density reduction and decrease of angle of repose. The oil inclusion reduced the pellet length , reduced both mash and pelleted feed density, reduced pellet unitdensity and increased the angle of repose of mash and pellet feed

Efeito de fitase sobre o desempenho zootécnico de frangos de corte consumindo dietas com maior ou menor teor de fitato.

Alimentos alternativos estão sendo estudados com o intuito de buscar matérias-primas em substituição ao milho e farelo de soja, os quais estão escassos e com um alto valor no mercado. Destes, uma opção é o farelo de trigo que pode ser incluído na dieta de aves em pequenas proporções, em virtude do alto teor de fibra e outros fatores antinutricionais. Para minimizar estes fatores pode-se optar pela suplementação de fitase exógena para aumentar a degradação do fitato do farelo de trigo, sendo que esta melhoria permite que o alimento seja usado em níveis mais elevados, fornecendo proporções consideráveis de fósforo e outros minerais, reduzindo os custos com alimentação e a poluição ambiental (POURREZA & CLASSEN, 2001; CLASSEN & BEDFORD, 2001; KERR et al., 2010). Com isso, o objetivo deste trabalho foi avaliar o efeito do farelo de trigo e fitase sobre os parâmetros de desempenho zootécnico de frangos de corte de um a 32 dias de idade

Adição de óleo como variável de predição da qualidade de peletes em rações de frangos de corte.

No presente trabalho foi avaliado o efeito da adição de níveis crescentes de inclusão de óleo de soja em dietas peletizadas de frangos sobre a qualidade do pelete. Os tratamentos foram compostos por cinco níveis de inclusão de óleo: T1 ?1,74%; T2 ?2,87%; T3?4,01%; T4 ?5,15%; T5 ?6,28%. Estas dietas foram submetidas à peletização em equipamento CPM, após a produção foram coletadas cinco amostras por tratamento. As amostras foram resfriadas e analisadas em relação à dureza e durabilidade do pelete e porcentagem de finos. O delineamento experimental foi inteiramente ao acaso com cinco tratamentos e cinco repetições. Os dados foram submetidos à análise de variância e as médias foram comparadas pelo teste t -Student, ao nível de 5%. Também foram testados contrastes polinomiais e geradas as equações de regressão.A inclusão crescente de óleo na dieta impactou negativamente na qualidade do pelete, com redução da dureza e durabilidade e aumento na porcentagem de finos. Entre 1,74% e 6,28% de adição de óleo, a cada 1% de aumento no nível de óleo, observou-se a redução de 0,86% na dureza e 4,43% na durabilidade do pelete, com aumento de 3,55% na porcentagem de finos na ração. This study evaluated the effect of increasing soybean oil levels on pellet qualityin broiler diets. The treatments consisted of five oil levels:T1 ?1.74 %, T2 ?2.87 %; T3 ?4.01%, T4 ?5.15%; T5 ?6.28 %. These diets were pelletized with CPM equipment, after production five samples per treatment were collected. Samples were cooled and analyzed for hardness and durability of the pellet and the percentage of fines. The experimental design was complete ly randomized with five treatments and five replicates. Data were subjected to analysis of variance and means were compared by t-Student Test at 5% level. Polynomial contrasts were also tested and generated regression equations. I ncreasing dietary oil levels impacted negatively on the pellet quality, with hardness and durability decrease and increase in the percentage of fines. the range of 1 .74% and 6. 28 % oil inclusion , every 1% increas e of soybean oil resulted in decrease of 0.86% in pellet hardness and 4. 43% in pellet durabi lity , increasing 3. 55 % the percentage of fines

A bright impulsive solar burst detected at 30 THz

Ground- and space-based observations of solar flares from radio wavelengths to gamma-rays have produced considerable insights but raised several unsolved controversies. The last unexplored wavelength frontier for solar flares is in the range of submillimeter and infrared wavelengths. Here we report the detection of an intense impulsive burst at 30 THz using a new imaging system. The 30 THz emission exhibited remarkable time coincidence with peaks observed at microwave, mm/submm, visible, EUV and hard X-ray wavelengths. The emission location coincides with a very weak white-light feature, and is consistent with heating below the temperature minimum in the atmosphere. However, there are problems in attributing the heating to accelerated electrons. The peak 30 THz flux is several times larger than the usual microwave peak near 9 GHz, attributed to non-thermal electrons in the corona. The 30 THz emission could be consistent with an optically thick spectrum increasing from low to high frequencies. It might be part of the same spectral component found at sub-THz frequencies whose nature remains mysterious. Further observations at these wavelengths will provide a new window for flare studies.Comment: 9 pages, 11 figures, accepted by Astrophysical Journal, March 23, 201

Usability improvements of the Thermipig model for precision pig farming

Pig livestock farming systems encounter several economic and environmental challenges, connected with meat price decrease, sanitary norms, emissions etc. To deal with these issues, methods and models to assess the performance of a pig production system have been developed. For instance, Thermipig model represents the pig fattening room and simulates performances of pigs at the batch level, taking into account interactions between the individual variability of pigs, farmer's practices, room characteristics and outdoor climate conditions. The model requires some static basic inputs fulfilled in several spreadsheets (such as rooms, pigs, and dietary characteristics) but also data files for voluminous variable inputs (such as outdoor temperature or climate control box parameters) for further modelling and outcome producing. This leads to challenges in data providing by the farmers and have to be improved. This paper deals with the implementation of the separate modules of the developed data warehouse system for usability improvements of the Thermipig model. The idea is to substitute input from the data files with online data input and automated variable processing by the model using the python script for connection to the remote data warehouse. The data warehouse system is extended with ‘Property Sets’ section dealing with all the operations that can be performed to a set of input variables. This approach demonstrates the ability of the data warehouse to act as data supplier for the remote model. As well the outcome of the model is also transferable back to the data warehouse for evaluation. This work is done within the Era-Net SuSan PigSys project - Improving pig system performance through a whole system approach