Universidade Federal de Minas Gerais

About: Universidade Federal de Minas Gerais is a education organization based out in Belo Horizonte, Minas Gerais, Brazil. It is known for research contribution in the topics: Population & Context (language use). The organization has 41631 authors who have published 75688 publications receiving 1249905 citations.

The gemini/nici planet-finding campaign: the frequency of planets around young moving group stars*

Abstract: We report results of a direct imaging survey for giant planets around 80 members of the ? Pic, TW Hya, Tucana-Horologium, AB Dor, and Hercules-Lyra moving groups, observed as part of the Gemini/NICI Planet-Finding Campaign. For this sample, we obtained median contrasts of ?H = 13.9 mag at 1'' in combined CH4 narrowband ADI+SDI mode and median contrasts of ?H = 15.1 mag at 2'' in H-band ADI mode. We found numerous (>70) candidate companions in our survey images. Some of these candidates were rejected as common-proper motion companions using archival data; we reobserved with Near-Infrared Coronagraphic Imager (NICI) all other candidates that lay within 400?AU of the star and were not in dense stellar fields. The vast majority of candidate companions were confirmed as background objects from archival observations and/or dedicated NICI Campaign followup. Four co-moving companions of brown dwarf or stellar mass were discovered in this moving group sample: PZ Tel B (36 ? 6 M Jup, 16.4 ? 1.0?AU), CD?35 2722B (31 ? 8 M Jup, 67 ? 4?AU), HD?12894B (0.46?? 0.08 M ?, 15.7 ? 1.0?AU), and BD+07 1919C (0.20 ? 0.03 M ?, 12.5 ? 1.4?AU). From a Bayesian analysis of the achieved H band ADI and ASDI contrasts, using power-law models of planet distributions and hot-start evolutionary models, we restrict the frequency of 1-20 M Jup companions at semi-major axes from 10-150?AU to <18% at a 95.4% confidence level using DUSTY models and to <6% at a 95.4% using COND models. Our results strongly constrain the frequency of planets within semi-major axes of 50?AU as well. We restrict the frequency of 1-20 M Jup companions at semi-major axes from 10-50?AU to <21% at a 95.4% confidence level using DUSTY models and to <7% at a 95.4% using COND models. This survey is the deepest search to date for giant planets around young moving group stars.

Annexin A1 and the Resolution of Inflammation: Modulation of Neutrophil Recruitment, Apoptosis, and Clearance

Abstract: Neutrophils (also named polymorphonuclear leukocytes or PMN) are essential components of the immune system, rapidly recruited to sites of inflammation, providing the first line of defense against invading pathogens. Since neutrophils can also cause tissue damage, their fine-tuned regulation at the inflammatory site is required for proper resolution of inflammation. Annexin A1 (AnxA1), also known as lipocortin-1, is an endogenous glucocorticoid-regulated protein, which is able to counterregulate the inflammatory events restoring homeostasis. AnxA1 and its mimetic peptides inhibit neutrophil tissue accumulation by reducing leukocyte infiltration and activating neutrophil apoptosis. AnxA1 also promotes monocyte recruitment and clearance of apoptotic leukocytes by macrophages. More recently, some evidence has suggested the ability of AnxA1 to induce macrophage reprogramming toward a resolving phenotype, resulting in reduced production of proinflammatory cytokines and increased release of immunosuppressive and proresolving molecules. The combination of these mechanisms results in an effective resolution of inflammation, pointing to AnxA1 as a promising tool for the development of new therapeutic strategies to treat inflammatory diseases.

Natural occurrence of 2-5A in interferon-treated EMC virus-infected L cells

Abstract: Until now the inierfer on-mediated 2′–5′ adenine oligonucleotide inhibitors (2–5A) of cell-free protein synthesis have not been detected in intact cells. Here we report their natural occurrence in interferon-treated, EMC virus-infected mouse L cells in amounts consistent with the idea that they play a part in the inhibition of virus growth.

Measuring the absolute Raman cross section of nanographites as a function of laser energy and crystallite size

Abstract: In this paper, the dependence of the differential Raman cross section $\ensuremath{\beta}$ of the $D$, $G$, ${D}^{\ensuremath{'}}$, and ${G}^{\ensuremath{'}}$ bands of nanographites on the excitation laser energy and also on the crystallite size is reported. We show that ${\ensuremath{\beta}}_{G}$ is proportional to the fourth power of the excitation laser energy $({E}_{l})$, as predicted by the Raman scattering theory. For the bands which arise from the double-resonance mechanism ($D$, ${D}^{\ensuremath{'}}$, and ${G}^{\ensuremath{'}}$), the differential cross section does not depend on ${E}_{l}$, explaining the strong dependence of the ratio ${I}_{D}∕{I}_{G}$ on the excitation laser energy ${E}_{l}$ used in the Raman experiment. The ${L}_{a}$ dependence of $D$ and ${D}^{\ensuremath{'}}$ band differential cross sections is measured, confirming that the proportionality ${I}_{D}∕{I}_{G}\ensuremath{\propto}{L}_{a}^{\ensuremath{-}1}$ originates from the strong dependence of ${\ensuremath{\beta}}_{D}$ on the inverse of the crystallite size. In the ${G}^{\ensuremath{'}}$ band case, the data show that its differential cross section increases with the increasing crystallite size ${L}_{a}$, following an opposite behavior when compared with the disorder induced $D$ and ${D}^{\ensuremath{'}}$ bands. An analysis on the dependence of the full width at half maximum $(\ensuremath{\Gamma})$ of the $D$, $G$, ${D}^{\ensuremath{'}}$, and ${G}^{\ensuremath{'}}$ bands on the crystallite size ${L}_{a}$ of nanographites is performed, showing that the phonon lifetime is proportional to the crystallite size.

Multi-UAV Routing for Area Coverage and Remote Sensing with Minimum Time.

Abstract: This paper presents a solution for the problem of minimum time coverage of ground areas using a group of unmanned air vehicles (UAVs) equipped with image sensors. The solution is divided into two parts: (i) the task modeling as a graph whose vertices are geographic coordinates determined in such a way that a single UAV would cover the area in minimum time; and (ii) the solution of a mixed integer linear programming problem, formulated according to the graph variables defined in the first part, to route the team of UAVs over the area. The main contribution of the proposed methodology, when compared with the traditional vehicle routing problem’s (VRP) solutions, is the fact that our method solves some practical problems only encountered during the execution of the task with actual UAVs. In this line, one of the main contributions of the paper is that the number of UAVs used to cover the area is automatically selected by solving the optimization problem. The number of UAVs is influenced by the vehicles’ maximum flight time and by the setup time, which is the time needed to prepare and launch a UAV. To illustrate the methodology, the paper presents experimental results obtained with two hand-launched, fixed-wing UAVs.