Astrometry with the MCAO instrument MAD - An analysis of single-epoch data obtained in the layer-oriented mode

Context: Current instrument developments at the largest telescopes worldwide have provisions for Multi-Conjugated Adaptive Optics (MCAO) modules. The large field of view and more uniform correction provided by these systems is not only highly beneficial for photometric studies but also for astrometric analysis of, e.g., large dense clusters and exoplanet detection and characterization. The Multi-conjugated Adaptive optics Demonstrator (MAD) is the first such instrument and was temporarily installed and tested at the ESO/VLT in 2007. We analyzed two globular cluster data sets in terms of achievable astrometric precision. Data were obtained in the layer-oriented correction mode, one in full MCAO correction mode with two layers corrected (NGC 6388) and the other applying ground-layer correction only (47 Tuc). Aims: We aim at analyzing the first available MCAO imaging data in the layer-oriented mode obtained with the MAD instrument in terms of astrometric precision and stability. Methods: We calculated Strehl maps for each frame in both data sets. Distortion corrections were performed and the astrometric precision was analyzed by calculating mean stellar positions over all frames and by investigation of the positional residuals present in each frame after transformation to a master-coordinate-frame. Results: The mean positional precision for stars between K = 14-18 mag is ~1.2 mas in the full MCAO correction mode data of the cluster NGC 6388. The precision measured in the GLAO data (47 Tuc) reaches ~1.0 mas for stars corresponding to 2MASS K magnitudes between 9 and 12. The observations were such that stars in these magnitude ranges correspond to the same detector flux range. The jitter movement used to scan a larger field of view introduced additional distortions in the frames, leading to a degradation of the achievable precision.Comment: 11 pages, 6 figures, accepted for publication in Astronomy & Astrophysic

Adenosine and Immune Imbalance in Visceral Leishmaniasis: The Possible Role of Ectonucleotidases

Visceral leishmaniasis (VL) is the most severe form of leishmaniasis and is responsible for most Leishmania-associated deaths. VL represents a serious public health problem that affects many countries. The immune response in leishmaniasis is very complex and is poorly understood. The Th1 versus Th2 paradigm does not appear to be so clear in visceral leishmaniasis, suggesting that other immunosuppressive or immune-evasion mechanisms contribute to the pathogenesis of VL. It has been demonstrated that generation of adenosine, a potent endogenous immunosuppressant, by extracellular enzymes capable to hydrolyze adenosine tri-nucleotide (ATP) at the site of infection, can lead to immune impairment and contribute to leishmaniasis progression. In this regard, this paper discusses the unique features in VL immunopathogenesis, including a possible role for ectonucleotidases in leishmaniasis

Universal deformation rings of modules for generalized Brauer tree algebras of polynomial growth

Let $k$ be an arbitrary field, $\Lambda$ be a $k$-algebra, and $V$ be a $\Lambda$-module. When it exists, the universal deformation ring $R(\Lambda,V)$ of $V$ is a $k$-algebra whose local homomorphisms from $R(\Lambda,V)$ to $R$ parametrize the lifts of $V$ up to $R\Lambda$, where $R$ is any appropriate complete, local commutative Noetherian $k$-algebra. Symmetric special biserial algebras, which coincide with Brauer graph algebras, can be viewed as generalizing the blocks of finite type $p$-modular group algebras. Bleher and Wackwitz classified the universal deformation rings for all modules for symmetric special biserial algebras with finite representation type. In this paper, we begin to address the tame case. Specifically, let $\Lambda$ be a symmetric special biserial algebra of polynomial growth which coincides with an acyclic Brauer graph algebra. We classify the universal deformation rings for those $\Lambda$-modules $V$ with stable endomorphism ring isomorphic to $k$. The latter is a natural condition, since it guarantees the existence of the universal deformation ring $R(\Lambda,V)$

A OMC e as limitações de políticas fiscais internas dos estados: o caso do Brasil

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Jurídicas, Programa de Pós-Graduação em Direito, Florianópolis, 2010As recentes decisões proferidas no âmbito do Sistema de Solução de Controvérsias da OMC têm motivado a necessidade de avaliação específica pelos Estados Membros quando da elaboração de suas políticas fiscais internas. Alguns casos relevantes vêm sendo objeto de decisões que impactam diretamente na soberania fiscal interna como elemento de distorção de práticas comerciais internacionais. O estudo aplicado dos casos na OMC demonstra que as cláusulas da nação mais favorecida (NMF) e do tratamento nacional (TN) tem cada vez mais suscitado debates na formulação de políticas fiscais que, até então, eram reflexo intransponível da soberania estatal de cada Estado. A questão é ainda mais evidente no caso do Acordo sobre Subsídios e Medidas Compensatórias, tendo em vista a recente decisão proferida em matéria tributária no Caso FSC. Outras normas da OMC também possuem clara afetação tributária. A análise dos casos e das decisões torna-se fundamental para que os Estados evitem questionamentos e aplicação de decisões contra suas políticas internas. No caso do Brasil, afora os cada vez mais recorrentes questionamentos, é preciso avaliar a possibilidade de exposição de políticas estatais no âmbito tributário a questionamentos no âmbito do mecanismo de solução de controvérsias. Os países não dispõem mais de uma liberdade plena na configuração de políticas fiscais sem que observe a adequação de tais políticas às normas da OMC.The recent decisions in the Dispute Settlement System of the WTO has been motivating the assessment of specific necessity by the Members when elaborating their internal fiscal policies. Some of the relevant disputes have being object of decisions that generates direct impact in the internal fiscal sovereignty as element of distortive international trade practices. The study of the WTO demonstrates that the most favorite nation (MFN) and the national treatment (NT) clauses has been generating debates in the formulation of fiscal policies which, until then, were unbridgeable when dealing with internal sovereign of each Member. This situation has been still more evident regarding the Subsidy and Countervailing Measures Agreement (SCM), having in mind the evidence of the recent decision of the FSC case. Other WTO rules also present clear tax relation. The analysis of the disputes and its decisions is fundamental to the Members assess its policies in order to avoid questions and disputes regarding its internal tax measures. In the case of Brazil, besides the recent consults by the other Members, it is necessary to assess the possibility of exposure of certain tax policies to future consults and disputes in the Dispute Settlement System. The countries don#t have a full sovereignty and freedom to configure and define the fiscal policies without observing the relation of such policies regarding the WTO rules

Experimental Based Evaluation of PV Inverters Harmonic and Interharmonic Distortion Due to Different Operating Conditions

This paper presents the results of comprehensive testing and subsequent detailed analysis of the obtained test results, evaluating harmonic and interharmonic performances of photovoltaic inverters (PVInvs) for a range of different operating conditions. The presented results indicate significant power-dependent changes in harmonic and interharmonic emissions of tested PVInvs for different supply voltage conditions (presence of voltage waveform distortions and various source impedance values). To correctly quantify and describe these changes in PVInv performance, this paper discusses and applies measurement procedures and metrics for evaluating harmonic and interharmonic emission recommended in existing standards, as well as some additional metrics and indicators. For some operating conditions, tested PVInvs significantly increase both harmonic and interharmonic emissions, and this paper also discusses the impact of PVInv control (e.g., maximum power point tracking control) as a possible origin of the interharmonic distortion

Inorganic Phosphate as an Important Regulator of Phosphatases

Cellular metabolism depends on the appropriate concentration of intracellular inorganic phosphate (Pi). Pi starvation-responsive genes appear to be involved in multiple metabolic pathways, implying a complex Pi regulation system in microorganisms and plants. A group of enzymes is required for absorption and maintenance of adequate phosphate levels, which is released from phosphate esters and anhydrides. The phosphatase system is particularly suited for the study of regulatory mechanisms because phosphatase activity is easily measured using specific methods and the difference between the repressed and derepressed levels of phosphatase activity is easily detected. This paper analyzes the protein phosphatase system induced during phosphate starvation in different organisms