Decision Tree Classifiers for Star/Galaxy Separation

We study the star/galaxy classification efficiency of 13 different decision tree algorithms applied to photometric objects in the Sloan Digital Sky Survey Data Release Seven (SDSS DR7). Each algorithm is defined by a set of parameters which, when varied, produce different final classification trees. We extensively explore the parameter space of each algorithm, using the set of $884,126$ SDSS objects with spectroscopic data as the training set. The efficiency of star-galaxy separation is measured using the completeness function. We find that the Functional Tree algorithm (FT) yields the best results as measured by the mean completeness in two magnitude intervals: $14\le r\le21$ ($85.2$) and $r\ge19$ ($82.1$). We compare the performance of the tree generated with the optimal FT configuration to the classifications provided by the SDSS parametric classifier, 2DPHOT and Ball et al. (2006). We find that our FT classifier is comparable or better in completeness over the full magnitude range $15\le r\le21$, with much lower contamination than all but the Ball et al. classifier. At the faintest magnitudes ($r>19$), our classifier is the only one able to maintain high completeness ($>$80%) while still achieving low contamination ($\sim2.5$). Finally, we apply our FT classifier to separate stars from galaxies in the full set of $69,545,326$ SDSS photometric objects in the magnitude range $14\le r\le21$.Comment: Submitted to A

Desenvolvimento de híbridos não convencionais de milho.

Trabalho publicado também no Livro de resumos do 28º CONGRESSO NACIONAL DE MILHO E SORGO; 4º SIMPÓSIO BRASILEIRO SOBRE A LAGARTA DO CARTUCHO, 2010, Goiânia

Sporotrichoid leishmaniasis: a cross-sectional clinical, epidemiological and laboratory study in Rio de Janeiro State, Brazil

Background Atypical presentations of cutaneous leishmaniasis include sporotrichoid leishmaniasis (SL), which is clinically described as a primary ulcer combined with lymphangitis and nodules and/or ulcerated lesions along its pathway. Aims To assess the differences between patients with sporotrichoid leishmaniasis and typical cutaneous leishmaniasis (CL). Methods From January 2004 to December 2010, 23 cases of SL (4.7%) were detected among 494 CL patients diagnosed at a reference center for the disease in Rio de Janeiro State, Brazil. These 23 cases were compared with the remaining 471 patients presenting CL. Results SL predominated in female patients (60.9%, p = 0.024), with older age (p = 0.032) and with lesions in upper limbs (52.2%, p = 0.028). CL affected more men (64.5%), at younger age, and with a higher number of lesions exclusively in lower limbs (34.8%). Conclusions Differences in clinical and epidemiological presentation were found between SL patients as compared to CL ones, in a region with a known predominance of Leishmania (Viannia) braziliensis. The results are similar to the features of most of the sporotrichosis patients as described in literature, making the differential diagnosis between ATL and sporotrichosis more important in overlapping areas for both diseases, like in Rio de Janeiro State

Chemical composition of aspidosperma ulei markgr. and antiplasmodial activity of selected indole alkaloids

A new indole alkaloid, 12-hydroxy-N-acetyl-21(N)-dehydroplumeran-18-oic acid (13), and 11 known indole alkaloids: 3,4,5,6-tetradehydro-β-yohimbine (3), 19(E)- hunteracine (4), β-yohimbine (5), yohimbine (6), 19,20-dehydro-17-α-yohimbine (7), uleine (10), 20-epi-dasycarpidone (11), olivacine (8), 20-epi-N-nor-dasycarpidone (14), N-demethyluleine (15) and 20(E)-nor-subincanadine E (12) and a boonein △-lactone 9, ursolic acid (1) and 1D,1O-methyl-chiro-inositol (2) were isolated from the EtOH extracts of different parts of Aspidosperma ulei Markgr. (Apocynaceae). Identification and structural elucidation were based on IR, MS, 1H- and 13C-NMR spectral data and comparison to literature data. The antiplasmodial and antimalarial activity of 1, 5, 6, 8, 10 and 15 has been previously evaluated and 1 and 10 have important in vitro and in vivo antimalarial properties according to patent and/or scientific literature. With the aim of discovering new antiplasmodial indole alkaloids, 3, 4, 11, 12 and 13 were evaluated for in vitro inhibition against the multi-drug resistant K1 strain of the human malaria parasite Plasmodium falciparum. IC50 values of 14.0 (39.9), 4.5 (16.7) and 14.5 (54.3) μg/mL (μM) were determined for 3, 11 and 12, respectively. Inhibitory activity of 3, 4, 11, 12 and 13 was evaluated against NIH3T3 murine fibroblasts. None of these compounds exhibited toxicity to fibroblasts (IC50 > 50 μg/mL). Of the five compounds screened for in vitro antiplasmodial activity, only 11 was active. © 2013 by the authors

Recovering plant data for Guinea-Bissau: implications for biodiversity knowledge of West Africa

ReviewThe rich plant diversity that characterizes the West African Region and the inherent knowledge of their flora and vegetation has been the backbone of scientific explorations during the past centuries. The evolution of botanical knowledge on Guinea-Bissau, throughout the 16th and 20th centuries is reviewed. We present and discuss floristic data collected by scientific expeditions between the mid-1700s to 1974, when the Portuguese colonial period ended. Expeditions undertaken by French naturalists provided some of the earliest plant collections. A list of herbarium specimens collected by the French naturalist Jardin, in the Bijagós Islands in ca. 1847–1858 is presented here for the first time, while in the late 1800s some Portuguese naturalists also explored Guinea-Bissau. During the colonial period (1915–1974), Gomes e Sousa published the first comprehensive study of the territory’s flora while Espírito Santo assembled the largest plant collection. Our review applies a multi-disciplinary perspective to fill important lacuna regarding biodiversity knowledge of this under-researchedWest African country. It constitutes the first study tracing the long term evolution of knowledge on Guinea Bissau's plant diversity, which provides the basis for understanding trends and research priorities, in particular in conservation and botanical fieldsinfo:eu-repo/semantics/publishedVersio