A Discussion on Supersymmetric Cosmic Strings with Gauge-Field Mixing

In this paper, following a stream of investigation on supersymmetric gauge theories with cosmic string solutions, we contemplate the possibility of building up a D-and-F term cosmic string by means of a gauge-field mixing in connection with a U(1) x U(1)'-symmetry. The spontaneous break of both gauge symmetry and supersymmetry are thoroughly analysed and the fermion zero-modes are worked out. The role of the gauge-field mixing parameter is elucidated in connection with the string configuration that comes out. As an application of the model presented here, we propose the possibility that the supersimetric cosmic string yield production of fermionic charge carriers that may eject, at their late stages, particles that subsequently decay to produce cosmic rays of ultra-high energy. In our work, it turns out that massive supersymmetric fermionic partners may be produced for a susy breaking scale in the range 10^{11} to 10^{13} GeV, which is compatible with the phenomenology of a gravitino mass at the TeV scale. We also determine the range of the gauge-field mixing parameter, \alpha, in connection with the mass scales of the present model.Comment: 7 pages, no figures, ReVTex format, to appear in New Journal of Physic

Sistema de produção de leite à base de pastagens cultivada e nativa melhorada na região de Bagé.

bitstream/item/109817/1/SISTEMA-DE-PRODUCAO-DE-LEITE.pd

Aurora B expression directly correlates with prostate cancer malignancy and influence prostate cell proliferation.

BACKGROUND: Chromosomal instability is one of the most common features of prostate cancer (PC), especially in advanced stages. Recent studies suggest that defects in mitotic checkpoints play a role in carcinogenesis. Lack of mitotic regulation induces aneuploidy in cancer cells acting thereafter as a driving force for malignant progression. Serine/threonine protein kinases of the Aurora genes family play an important throughout the entire cell cycle. In that Aurora B regulates chromosome segregation by ensuring the orientation of sister chromatids. As a consequence, the overexpression of Aurora B in diploid human cells NHDF induces the appearance of multinucleate cells. METHODS: Archive samples of normal and neoplastic prostate tissue, and prostate derived cell lines were screened for the expression of Aurora B. RESULTS: Immunohistochemical analysis showed increased nuclear expression of Aurora-B in high Gleason grade PCs respect to low and intermediate grade cases and in all cancers in respect to hyperplastic and normal glands. Furthermore, in the high Gleason grade anaplastic cancer tissues Aurora B expression was accompanied by the phosphorylation of the histone H3. In analogy to the in vivo situation, Aurora B was vigorously expressed in the androgen independent PC cell lines PC3 and DU145, while a very modest expression of the kinase was observed in the androgen sensitive LnCap cells and in the EPN cells, a line of epithelial cells derived from normal prostate tissue. In addition, in PC3 cells Aurora B expression is accompanied the by the phosphorylation of the histone H3. The block of Aurora B expression induced by an inhibitor of Aurora kinase activity significantly reduced the growth of prostate carcinoma cells, but not that of non-transformed EPN cells. CONCLUSIONS: Our data are the first demonstration of a role of Aurora B in PC progression. In addition, the observation that Aurora B specific inhibitors interfere with PC cell proliferation but not with that of non-transformed prostate epithelial cells suggest that Aurora B is a potential therapeutic target for PC

Overturning established chemoselectivities : selective reduction of arenes over malonates and cyanoacetates by photoactivated organic electron donors

The prevalence of metal-based reducing reagents, including metals, metal complexes, and metal salts, has produced an empirical order of reactivity that governs our approach to chemical synthesis. However, this reactivity may be influenced by stabilization of transition states, intermediates, and products through substrate-metal bonding. This article reports that in the absence of such stabilizing interactions, established chemoselectivities can be overthrown. Thus, photoactivation of the recently developed neutral organic superelectron donor 5 selectively reduces alkyl-substituted benzene rings in the presence of activated esters and nitriles, in direct contrast to metal-based reductions, opening a new perspective on reactivity. The altered outcomes arising from the organic electron donors are attributed to selective interactions between the neutral organic donors and the arene rings of the substrates

Multivariate Analysis Applied to Forestry Agricultural Sciences: The Model-Directed Study

This is a literature review that aimed to find articles that exemplify and describe the use of multivariate analysis in different fields of Forest Agricultural Sciences, considering effective practices using multivariate statistical techniques for the simultaneous processing of data. For data collection were selected for the meta-analysis of 70 technical articles of which 54 were employed in the study directed to the use of multivariate techniques applied in the areas of agricultural sciences. The results showed thatstudies directed to certain areas within the Forest Agricultural Sciences exhibit some regularity in the use of multivariate analysis, and most application analyzes were more usual as the Cluster Analysis (AA) and Principal Component Analysis (PCA). Thus the use of multivariate analysis studies and evaluations of experiments in Agricultural Sciences proved to great value to allow greater clarity and better interpretation of dealing with complex phenomena

A novel approach to improve GNSS Precise Point Positioning during strong ionospheric scintillation: theory and demonstration

At equatorial latitudes, ionospheric scintillation is the major limitation in achieving high-accuracy GNSS positioning. This is because scintillation affects the tracking ability of GNSS receivers causing losses of lock and degradation on code pseudorange and carrier phase measurements, thus degrading accuracy. During strong ionospheric scintillation, such effects are more severe and GNSS users cannot rely on the integrity, reliability, and availability required for safety-critical applications. In this paper, we propose a novel approach able to greatly reduce these effects of scintillation on precise point positioning (PPP). Our new approach consists of three steps: 1) a new functional model that corrects the effects of range errors in the observables; 2) a new stochastic model that uses these corrections to generate more accurate positioning; and 3) a new strategy to attenuate the effects of losses of lock and consequent ambiguities re-initializations that are caused by the need to re-initialize the tracking. We demonstrate the effectiveness of our method in an experiment using a 30-day static dataset affected by different levels of scintillation in the Brazilian southeastern region. Even with limitations imposed by data gaps, our results demonstrate improvements of up to 80% in the positioning accuracy. We show that, in the best cases, our method can completely negate the effects of ionospheric scintillation and can recover the original PPP accuracy that would have existed without any scintillation. The significance of this paper lies in the improvement it offers in the integrity, reliability, and availability of GNSS services and applications.</p