3,901 research outputs found

    Germinação e morfologia de plântulas de Licania macrophylla (Crhysobalanaceae), nativa da floresta de várzea do Estuário, Amapá, Brasil.

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    A Amazônia possui muitas espécies arbóreas com fins econômicos e de estudos científicos, dentre estas encontra-se Licania macrophylla Benth., conhecida popularmente por ?anoerá?. Possui uma grande distribuição na América do Sul, podendo ser encontrada principalmente em áreas de várzea das regiões do Baixo Amazonas [1]. As comunidades amazônicas a utilizam no tratamento de doenças como parasitoses amebianas e distúrbios diarreicos e para alimentação preparam o macerado das sementes [2]. Apesar de sua importância, pouco se sabe sobre o desenvolvimento inicial dessa espécie e como identificá-la em campo. Estudos sobre germinação e morfologia de plântulas são fundamentais para subsidiar a produção de mudas em viveiros e avaliar a regeneração natural, ações importantes para a manutenção de espécies florestais com interesse econômico. Portanto, o objetivo foi avaliar a germinação e a morfologia de plântulas dessa espécie

    Hydroxychloroquine in pediatric idiopathic pulmonary hemosiderosis – A case report

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    Os autores apresentam o caso de uma criança com hemossiderose pulmonar idiopática grave, que, após ter iniciado tratamento com hidroxicloroquina, apresentou alteração do seu curso clínico, com melhoria significativa e duradoura. A eficácia desta terapêutica é salientada. Reportam ainda a ocorrência de exacerbação clínica, com hemoptise, após administração de vacina antigripal. The authors present the case of a child with severe idiopathic pulmonary hemosiderosis who after having begun treatment with hydroxychloroquine had a significant and lasting improvement. The efficacy of this therapeutic is pointed out. They also report the occurrence of clinical exacerbation, with hemoptysis, after receiving an influenza vaccine

    Large and small-scale structures and the dust energy balance problem in spiral galaxies

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    The interstellar dust content in galaxies can be traced in extinction at optical wavelengths, or in emission in the far-infrared. Several studies have found that radiative transfer models that successfully explain the optical extinction in edge-on spiral galaxies generally underestimate the observed FIR/submm fluxes by a factor of about three. In order to investigate this so-called dust energy balance problem, we use two Milky Way-like galaxies produced by high-resolution hydrodynamical simulations. We create mock optical edge-on views of these simulated galaxies (using the radiative transfer code SKIRT), and we then fit the parameters of a basic spiral galaxy model to these images (using the fitting code FitSKIRT). The basic model includes smooth axisymmetric distributions along a S\'ersic bulge and exponential disc for the stars, and a second exponential disc for the dust. We find that the dust mass recovered by the fitted models is about three times smaller than the known dust mass of the hydrodynamical input models. This factor is in agreement with previous energy balance studies of real edge-on spiral galaxies. On the other hand, fitting the same basic model to less complex input models (e.g. a smooth exponential disc with a spiral perturbation or with random clumps), does recover the dust mass of the input model almost perfectly. Thus it seems that the complex asymmetries and the inhomogeneous structure of real and hydrodynamically simulated galaxies are a lot more efficient at hiding dust than the rather contrived geometries in typical quasi-analytical models. This effect may help explain the discrepancy between the dust emission predicted by radiative transfer models and the observed emission in energy balance studies for edge-on spiral galaxies.Comment: 9 pages, 5 figures, accepted for publication in A&

    Terpene Adsorption Analysis in Tedlar Air Sampling Bags

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    Tedlar® air sampling bags, which are composed of a polyvinyl fluoride polymer, are the EPA recommended bags used in several whole-air sampling and analytical methods for determining the presence of volatiles. Recent studies suggest that compounds which exhibit hydrogen bonding, as well as those that have a low vapor pressure, will tend to adsorb to the Tedlar® bags at a high rate. Furthermore, alkenes seem to display significant adsorption rates. For example, terpenes are a type of volatile organic compound (VOC) which contain the alkene functional group, and are found in oils produced by plants and some insects. In the current experiment, the adsorption rates of three specific terpenes introduced into Tedlar® bags were analyzed. The terpenes in question are alloaromadendrene (MF: C15H24, MW: 204.36 g/mol, VP: 0.023 mm/Hg @ 25.00°C), caryophyllene (MF: C15H24, MW: 204.36 g/mol, VP: 0.013 mm/Hg @ 25.00°C), and limonene (MF: C10H16, MW: 136.24 g/mol, VP: 1.980 mm/Hg @ 25.00°C), which are cyclic and contain multiple alkenes. After the introduction of the three compounds into each of five Tedlar® bags, an air sample of each bag was collected and analyzed daily using gas chromatography-mass spectroscopy (GC-MS). The results show that after a period of equilibration, caryophyllene and alloraromadendrene showed a steady decrease in presence by the fourth day, whereas limonene, a smaller molecule, seemed to increase in the bag, suggesting that larger molecules, such as caryophyllene and alloaromadendrene, which also contain lower vapor pressures, are adsorbing at a faster rate than that of the smaller limonene. These findings give insight as to how certain experiments may be influenced by equipment used, and provides information on how to accommodate for these sources of potential error. Further research regarding the experiment will include a desorption study, which may aid in identifying the affinity of certain compounds to the Tedlar® bag, and provide information on the feasibility of reusing bags for terpene analysis

    Germinação e morfologia de plântulas de Hymenaea oblongifolia var. oblongifolia (Fabaceae) em floresta de várzea do Estuário, Amapá.

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    A árvore Hymenaea oblongifolia Huber var. oblongifolia (Fabaceae), conhecida como Jutaí, ocorre nos estados do Acre, Amapá, Amazonas, Pará e Rondônia. É frequente nas florestas de várzea e de terra firme [1]. A maioria das espécies desse gênero possui algum valor econômico, pois, fornece madeira de qualidade, valiosas resinas, frutos comestíveis e usos na medicina popular [2]. Desse modo, os estudos morfológicos auxiliam na identificação correta, interpretação de testes laboratoriais e o reconhecimento da espécie em bancos de sementes do solo e em fase de plântulas em formações florestais. Contribuem também para o estudo dos mecanismos de dispersão, sucessão e regeneração natural da espécie [3]. Neste contexto, o objetivo foi avaliar a germinação e descrever a morfologia das plântulas dessa espécie
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