Lorentz-breaking effects in scalar-tensor theories of gravity

In this work, we study the effects of breaking Lorentz symmetry in scalar-tensor theories of gravity taking torsion into account. We show that a space-time with torsion interacting with a Maxwell field by means of a Chern-Simons-like term is able to explain the optical activity in syncrotron radiation emitted by cosmological distant radio sources. Without specifying the source of the dilaton-gravity, we study the dilaton-solution. We analyse the physical implications of this result in the Jordan-Fierz frame. We also analyse the effects of the Lorentz breaking in the cosmic string formation process. We obtain the solution corresponding to a cosmic string in the presence of torsion by keeping track of the effects of the Chern-Simons coupling and calculate the charge induced on this cosmic string in this framework. We also show that the resulting charged cosmic string gives us important effects concerning the background radiation.The optical activity in this case is also worked out and discussed.Comment: 10 pages, no figures, ReVTex forma

Uso de promotores de crescimento para cabritos leiteiros, fase de aleitamento.

A fase de aleitamento de cabritos leiteiros esta inserida no periodo de seu maior potencial de crescimento. Nesta fase, os animais sao susceptiveis as enterites (diarreias) de origem alimentar e/ou infecciosa, consideradas como a principais causas de baixo desempenho de cabritos. Assim, este experimento foi conduzido para avaliar o efeito de promotores de crescimento sobre o desempenho de cabritos leiteiros, na fase de aleitamento. Foram utilizados 30 crias, femeas, sendo 15 da raca Saanen e 15 da raca Anglo-Nubiana. Os animais foram aleitados com leite de vaca durante todo o periodo experimental e receberam capim elefante e concentrado ad libitum a partir de 15 dias de idade. Os tratamentos foram: T1= leite de vaca, T2= leite de vaca+salinomicina e T3= leite de vaca+probiotico. Os resultados mostraram que nao houve diferenca (P>0,05) entre tratamentos. Os valores encontrados para ganho de peso (g/animal/dia) e para peso ao desaleitamento (Kg) foram: 126,5 126,8, 122,4 e 10,2, 10,4 e 10,0, respectivamente. Nao foi observado ocorrencia de enterite nos animais. Entre raca, tambem, nao foi detectada diferenca (P>0,05) significativa. [Use of growth promotors for dairy kids, at the suckling phase]. The suckling phase of dairy kids is the period of higher potential for growth. In this phase, the animals are susceptible to the alimentary and infectious enteritis. These types of enteritis are the principal cause of low kid's performance. So, this experiment was carried out to evaluate the effect of growth promoters on performance of dairy kids during the suckling phase. Thirty females kids of the Anglo-nubiana breed (15) and of the Saanen breed (15) were used. The animals were artificially reared with cow milk, during the trial and they received napiergrass (Pennisetum purpureum) and concentrate ad libitum after 15 days of age. The treatments were T1 - cow milk, T2 - cow milk + salinomicine T3 - cow milk + probiotic. The results showed that there was no significant difference (P>0.05) among treatments and breed. The values to weight gain (g/animal/day) and wean weight (kg/animal) were 126.5, 126.8, 122.4 e 10.2, 10.4 e 10.0, respectively. There was not enteritis in animals

The WFCAM Multi-wavelength Variable Star Catalog

Stellar variability in the near-infrared (NIR) remains largely unexplored. The exploitation of public science archives with data-mining methods offers a perspective for the time-domain exploration of the NIR sky. We perform a comprehensive search for stellar variability using the optical-NIR multi-band photometric data in the public Calibration Database of the WFCAM Science Archive (WSA), with the aim of contributing to the general census of variable stars, and to extend the current scarce inventory of accurate NIR light curves for a number of variable star classes. We introduce new variability indices designed for multi-band data with correlated sampling, and apply them for pre-selecting variable star candidates, i.e., light curves that are dominated by correlated variations, from noise-dominated ones. Pre-selection criteria are established by robust numerical tests for evaluating the response of variability indices to colored noise characteristic to the data. We find 275 periodic variable stars and an additional 44 objects with suspected variability with uncertain periods or apparently aperiodic variation. Only 44 of these objects had been previously known, including 11 RR~Lyrae stars in the outskirts of the globular cluster M3 (NGC~5272). We provide a preliminary classification of the new variable stars that have well-measured light curves, but the variability types of a large number of objects remain ambiguous. We classify most of the new variables as contact binary stars, but we also find several pulsating stars, among which 34 are probably new field RR~Lyrae and 3 are likely Cepheids. We also identify 32 highly reddened variable objects close to previously known dark nebulae, suggesting that these are embedded young stellar objects. We publish our results and all light-curve data as the WFCAM Variable Star Catalog.Comment: 21 pages, 11 figure

Cultivation and genetics of Artemisia annua L. for increased production of the antimalarial artemisinin

Malaria has been treated for over 350 years with quinine and quinine-derived drugs. However, in several areas of the world, some strains of the malarial parasite Plasmodium falciparum have developed resistance against these drugs. Recently, the World Health Organization (WHO) recommended the use of artemisinin-combination treatments (ACT) as the first-line treatment for multidrug-resistant falciparum malaria. The WHO estimates that current supplies of artemisinin are sufficient for only 30 million ACT, and is foreseeing the need for 130-220 million ACT in 2005 (WHO, 2004). Current research on the production of synthetic artemisinin-like compounds by the Roll Back Malaria project, pharmaceutical companies and academia resulted in a promising synthetic artemisinin-like compound (OZ277) which is currently undergoing phase I clinical trials. In about 5 years this drug is expected to be approved and made available to the public, however, meeting current global demands for ACT depends on the immediate availability of affordable artemisinin-derived drugs. This will involve expansion of the area under cultivation of Artemisia annua and improved methods of cultivation and processing of raw material, associated with more efficient methods for extraction and purification of artemisinin from plant material. This review addresses the agricultural, environmental and genetic aspects that may be useful in the successful large-scale cultivation of A. annua and for producing the antimalarial artemisinin in areas where it is urgently needed today. It also includes geographic aspects (latitude and altitude), which will help make decisions about crop establishment in tropical countries, and includes a list of Good Agricultural and Collection Practices for A. annu

On the strategy frequency problem in batch Minority Games

Ergodic stationary states of Minority Games with S strategies per agent can be characterised in terms of the asymptotic probabilities $\phi_a$ with which an agent uses $a$ of his strategies. We propose here a simple and general method to calculate these quantities in batch canonical and grand-canonical models. Known analytic theories are easily recovered as limiting cases and, as a further application, the strategy frequency problem for the batch grand-canonical Minority Game with S=2 is solved. The generalization of these ideas to multi-asset models is also presented. Though similarly based on response function techniques, our approach is alternative to the one recently employed by Shayeghi and Coolen for canonical batch Minority Games with arbitrary number of strategies.Comment: 17 page