The Low Energy Limit of the Chern-Simons Theory Coupled to Fermions

We study the nonrelativistic limit of the theory of a quantum Chern--Simons field minimally coupled to Dirac fermions. To get the nonrelativistic effective Lagrangian one has to incorporate vacuum polarization and anomalous magnetic moment effects. Besides that, an unsuspected quartic fermionic interaction may also be induced. As a by product, the method we use to calculate loop diagrams, separating low and high loop momenta contributions, allows to identify how a quantum nonrelativistic theory nests in a relativistic one.Comment: 18 pages, 8 figures, Late

Generation of higher derivatives operators and electromagnetic wave propagation in a Lorentz-violation scenario

We study the perturbative generation of higher-derivative operators as corrections to the photon effective action, which are originated from a Lorentz violation background. Such corrections are obtained, at one-loop order, through the proper-time method, using the zeta function regularization. We focus over the lowest order corrections and investigate their influence in the propagation of electromagnetic waves through the vacuum, in the presence of a strong, constant magnetic field. This is a setting of experimental relevance, since it bases active efforts to measure non linear electromagnetic effects. After surprising cancellations of Lorentz violating corrections to the Maxwell's equation, we show that no effects of the kind of Lorentz violation we consider can be detected in such a context.Comment: v2: 13 pages, no figures, section IV considerably rewritten, main results unchanged and are now obtained in a simpler way. To appear in PL

Single and Double Photoionization and Photodissociation of Toluene by Soft X-rays in Circumstellar Environment

The formation of polycyclic aromatic hydrocarbons (PAHs) and their methyl derivatives occurs mainly in the dust shells of asymptotic giant branch (AGB) stars. The bands at 3.3 and 3.4 $\mu$m, observed in infrared emission spectra of several objects, are attributed C-H vibrational modes in aromatic and aliphatic structures, respectively. In general, the feature at 3.3 $\mu$m is more intense than the 3.4 $\mu$m. Photoionization and photodissociation processes of toluene, the precursor of methylated PAHs, were studied using synchrotron radiation at soft X-ray energies around the carbon K edge with time-of-flight mass spectrometry. Partial ion yields of a large number of ionic fragments were extracted from single and 2D-spectra, where electron-ion coincidences have revealed the doubly charged parent-molecule and several doubly charged fragments containing seven carbon atoms with considerable abundance. \textit{Ab initio} calculations based on density functional theory were performed to elucidate the chemical structure of these stable dicationic species. The survival of the dications subjected to hard inner shell ionization suggests that they could be observed in the interstellar medium, especially in regions where PAHs are detected. The ionization and destruction of toluene induced by X-rays were examined in the T Dra conditions, a carbon-rich AGB star. In this context, a minimum photodissociation radius and the half-life of toluene subjected to the incidence of the soft X-ray flux emitted from a companion white dwarf star were determined.Comment: 11 pages, 4 figures, accept for publication in Ap

Dynamical analysis of the cluster pair: A3407 + A3408

We carried out a dynamical study of the galaxy cluster pair A3407 \& A3408 based on a spectroscopic survey obtained with the 4 meter Blanco telescope at the CTIO, plus 6dF data, and ROSAT All-Sky-Survey. The sample consists of 122 member galaxies brighter than $m_R=20$. Our main goal is to probe the galaxy dynamics in this field and verify if the sample constitutes a single galaxy system or corresponds to an ongoing merging process. Statistical tests were applied to clusters members showing that both the composite system A3407 + A3408 as well as each individual cluster have Gaussian velocity distribution. A velocity gradient of $\sim 847\pm 114$ $\rm km\;s^{-1}$ was identified around the principal axis of the projected distribution of galaxies, indicating that the global field may be rotating. Applying the KMM algorithm to the distribution of galaxies we found that the solution with two clusters is better than the single unit solution at the 99\% c.l. This is consistent with the X-ray distribution around this field, which shows no common X-ray halo involving A3407 and A3408. We also estimated virial masses and applied a two-body model to probe the dynamics of the pair. The more likely scenario is that in which the pair is gravitationally bound and probably experiences a collapse phase, with the cluster cores crossing in less than $\sim$1 $h^{-1}$ Gyr, a pre-merger scenario. The complex X-ray morphology, the gas temperature, and some signs of galaxy evolution in A3408 suggests a post-merger scenario, with cores having crossed each other $\sim 1.65 h^{-1}$Gyr ago, as an alternative solution.Comment: 17 pages, 12 figures, submitted to MNRAS, accepted 2016 May 9. Received 2016 May 9; in original form 2016 April 1

The role of bacteria in pine wilt disease: insights from microbiome analysis.

Pine Wilt Disease (PWD) has a significant impact on Eurasia pine forests. The microbiome of the nematode (the primary cause of the disease), its insect vector, and the host tree may be relevant for the disease mechanism. The aim of this study was to characterize these microbiomes, from three PWD-affected areas in Portugal, using Denaturing Gradient Gel Electrophoresis, 16S rRNA gene pyrosequencing, and a functional inference-based approach (PICRUSt). The bacterial community structure of the nematode was significantly different from the infected trees but closely related to the insect vector, supporting the hypothesis that the nematode microbiome might be in part inherited from the insect. Sampling location influenced mostly the tree microbiome (P < 0.05). Genes related both with plant growth promotion and phytopathogenicity were predicted for the tree microbiome. Xenobiotic degradation functions were predicted in the nematode and insect microbiomes. Phytotoxin biosynthesis was also predicted for the nematode microbiome, supporting the theory of a direct contribution of the microbiome to tree-wilting. This is the first study that simultaneously characterized the nematode, tree and insect-vector microbiomes from the same affected areas, and overall the results support the hypothesis that the PWD microbiome plays an important role in the disease's development

Evidence for two-electron processes in the mutual neutralization of O- with O+ and N+ at Subthermal Collision Energies

We have measured total absolute cross sections for the Mutual Neutralization (MN) of O- with O+/N+. A fine resolution (of about 50 meV) in the kinetic energy spectra of the product neutral atoms allows unique identification of the atomic states participating in the mutual neutralization process. Cross sections and branching ratios have also been calculated down to 1 meV center-of-mass collision energy for these two systems with a multi-channel Landau-Zener model and an asymptotic method for the ionic-covalent coupling matrix elements. The importance of two-electron processes in one-electron transfer is demonstrated by the dominant contribution of a core-excited configuration of the nitrogen atom in N+ + O- collisions. This effect is partially accounted for by introducing configuration mixing in the evaluation of coupling matrix elements.Comment: 5 pages, 4 figure

Sistema de produção de leite em pastagem de Capim -Tanzânia: ações de transferência de tecnologia.

bitstream/CPAMN/20173/1/CT185.pd

Estratégias terapêuticas para a obesidade pediátrica e sua influência nos marcadores de risco cardiovascular

Pediatric obesity is an important public health problem nowadays. Portugal is no exception, being one third of children and adolescent either overweight or obese. The behavioral approach is the basilar stone of obese treatment nowadays. It focuses in change lifestyle, substituting unhealthy habits by new, healthier, ones.A great number of strategies have been studied to try to respond to this growing problem, with varying results. The heterogeneity present in the scientific literature is likely to be explained by different study designs and targeted populations. Nevertheless, the results, in general, support that improvements in diet and increase in physical exercise pattern are associated with improvements in risk factors for cardiovascular disease, namely an atherogenic lipid profile, insulin resistance and inflammation, besides the reduction in adiposity itself.The combination of diet and exercise in the same intervention appear to be beneficial and complementary. However, different types of diet and exercise might lead to different results.The use of pharmacological adjuvants in pediatric obesity treatment is very limited in clinical practice due, mainly, to the lack of adequate studies; however some options have demonstrated to contribute to a small, but consistent, improvement in adiposity. Surgery, on the other hand, is the last therapeutic option and should be considered only in the more severe cases.Pediatric obesity tends to track until adulthood, and is associated with increased risk of cardiovascular disease in the future. Acting as early as possible in an individual life, when health habits are easier to acquire, and likelier to be kept, is crucial.Governments, including the Portuguese, have been paying more attention to this issue in the last years. However, much more can be made in general policies to create a less obesogenic environment and make the healthy choices the easier ones.A obesidade pediátrica é actualmente um problema de saúde pública crescente. Portugal não é excepção sendo que um terço da população pediátrica e adolescente apresenta excesso de peso ou mesmo obesidade. A abordagem comportamental é a pedra basilar dos tratamentos da obesidade, focando-se em alterações do estilo de vida e substituição de hábitos nefastos por outros  saudáveis.Um elevado número de estratégias foram estudadas para responder a este problema crescente apresentando, contudo, resultados variáveis. A heterogeneidade de resultados apresentada na literatura cientifica pode ser explicada por diferentes desenhos de estudo e de populações alvo. Não obstante, os resultados apontam no sentido de que melhorias na dieta e no padrão de actividade fisica estão associados com melhorias no factor de risco cardiovascular, nomeadamente do perfil aterogénico lipidico, resistência à insulina, inflamação, para além da redução da própria adiposidade.A combinação de dieta e exercício na mesma intervenção parece ser benéfica e complementar. No entanto, diferentes tipos de actividade fisica e de dieta podem levar a resultados diferentes. O uso de adjuvantes farmacológicos no tratamento da obesidade pediátrica é altamente limitado na prática clinica, especialmente devido à falta de estudos adequeados; contudo algumas opções demonstraram contribuir para uma pequena mas consistente melhoria da adiposidade. A cirurgia é uma solução de ultimo recurso e para casos extremos.A obesidade pediátrica tende a manter-se até à idade adulta e está associada a um aumento do risco cardiovascular futuro. Uma actuação tão precoce quanto possível, quando é mais fácil a aquisição de habitos adequados, é crucialOs governos estão a prestar cada vez mais atenção a este assunto. Contudo, muito mais pode ser feito em termos de politicas globais, no sentido de criar um ambiente menos propicio à obesidade e favorável à escolha de opções mais saudáveis