Decomposition in tropical forests: a pan-tropical study of the effects of litter type, litter placement and mesofaunal exclusion across a precipitation gradient

1. Litter decomposition recycles nutrients and causes large fluxes of carbon dioxide into the atmosphere. It is typically assumed that climate, litter quality and decomposer communities determine litter decay rates, yet few comparative studies have examined their relative contributions in tropical forests. 2. We used a short-term litterbag experiment to quantify the effects of litter quality, placement and mesofaunal exclusion on decomposition in 23 tropical forests in 14 countries. Annual precipitation varied among sites (760-5797 mm). At each site, two standard substrates (Raphia farinifera and Laurus nobilis) were decomposed in fine- and coarse-mesh litterbags both above and below ground for approximately 1 year. 3. Decomposition was rapid, with >95% mass loss within a year at most sites. Litter quality, placement and mesofaunal exclusion all independently affected decomposition, but the magnitude depended upon site. Both the average decomposition rate at each site and the ratio of above- to below-ground decay increased linearly with annual precipitation, explaining 60-65% of among-site variation. Excluding mesofauna had the largest impact on decomposition, reducing decomposition rates by half on average, but the magnitude of decrease was largely independent of climate. This suggests that the decomposer community might play an important role in explaining patterns of decomposition among sites. Which litter type decomposed fastest varied by site, but was not related to climate. 4. Synthesis. A key goal of ecology is to identify general patterns across ecological communities, as well as relevant site-specific details to understand local dynamics. Our pan-tropical study shows that certain aspects of decomposition, including average decomposition rates and the ratio of above- to below-ground decomposition are highly correlated with a simple climatic index: mean annual precipitation. However, we found no relationship between precipitation and effects of mesofaunal exclusion or litter type, suggesting that site-specific details may also be required to understand how these factors affect decomposition at local scales.

Effect of cerium on structure modifications of a hybrid sol-gel coating, its mechanical properties and anti-corrosion behavior

An organic-inorganic hybrid coating was developed to improve the corrosion resistance of the aluminum alloy AA 2024-T3. Organic and inorganic coatings derived from glycidoxypropyltrimethoxysilane (GPTMS) and aluminum tri-sec-butoxide Al((OBu)-Bu-s)(3), with different cerium contents, were deposited onto aluminum by dip-coating process. Corrosion resistance and mechanical properties were investigated by electrochemical impedance measurements and nano-indentation respectively. An optimal cerium concentration of 0.01 M was evidenced. To correlate and explain the hybrid coating performances in relation to the cerium content, NMR experiments were performed. It has been shown that when the cerium concentration in the hybrid is higher than 0.01 M there are important modifications in the hybrid structure that account for the mechanical properties and anti-corrosion behavior of the sol-gel coating. (C) 2012 Elsevier Ltd. All rights reserved.

Collagen is reduced and disrupted in human aneurysms and dissections of ascending aorta

In ascending aorta aneurysms, there is an enlargement of the whole vessel, whereas aortic dissections (ADs) are characterized by the cleavage of the wall into 2 sheets at the external half. We searched if alterations in collagen could be related to these diseases. Sections of aortas from 14 case patients with acute dissections, 10 case patients with aneurysms, and 9 control subjects were stained with picrosirius. Slides were analyzed under polarized microscopy to evaluate the structure of collagen fibers. The proportion of collagen was calculated in each half of the medial layer by color detection in a computerized image analysis system. Collagen appearance under polarized light was consistent with collagenolysis. The mean collagen proportions at the inner and outer halves, respectively, were 0.50 +/- 0.13 and 0.40 +/- 0.08 in the control group, 0.20 +/- 0.10 and 0.18 +/- 0.12 in the AD group, and 0.33 +/- 0.12 and 0.19 +/- 0.12 in the aneurysm group. The AD (P < .01) and control (P = .04) groups had less collagen at the external half, no difference was found in the aneurysm group (P = .71). In both halves, there was less collagen in the case patients than in the control subjects (all P < .01), but at the internal half, the decrease was significantly greater in the case patients with aneurysms than in those with dissections (P = .03; at the external half, P = .99). Aortic dissections and aneurysms show a decrease in collagen content that could be related to a weakness of the wall underlying the diseases, but the locations of the decrease differ: in dissections, it is situated mostly at the external portion of the media (site of cleavage), whereas in aneurysms, it is more diffuse, consistent with the global enlargement. (c) 2008 Elsevier B.V. All rights reserved.

Response to Treatment in a Prospective Cohort of Patients with Large Ulcerated Lesions Suspected to Be Buruli Ulcer (Mycobacterium ulcerans Disease)

Background: The World Health Organization (WHO) advises treatment of Mycobacterium ulcerans disease, also called Buruli ulcer'' (BU), with a combination of the antibiotics rifampicin and streptomycin (R+S), whether followed by surgery or not. In endemic areas, a clinical case definition is recommended. We evaluated the effectiveness of this strategy in a series of patients with large ulcers of >= 10 cm in longest diameter in a rural health zone of the Democratic Republic of Congo (DRC).Methods: A cohort of 92 patients with large ulcerated lesions suspected to be BU was enrolled between October 2006 and September 2007 and treated according to WHO recommendations. The following microbiologic data were obtained: Ziehl-Neelsen (ZN) stained smear, culture and PCR. Histopathology was performed on a sub-sample. Directly observed treatment with R+S was administered daily for 12 weeks and surgery was performed after 4 weeks. Patients were followed up for two years after treatment.Findings: Out of 92 treated patients, 61 tested positive for M. ulcerans by PCR. PCR negative patients had better clinical improvement than PCR positive patients after 4 weeks of antibiotics (54.8% versus 14.8%). For PCR positive patients, the outcome after 4 weeks of antibiotic treatment was related to the ZN positivity at the start. Deterioration of the ulcers was observed in 87.8% (36/41) of the ZN positive and in 12.2% (5/41) of the ZN negative patients. Deterioration due to paradoxical reaction seemed unlikely. After surgery and an additional 8 weeks of antibiotics, 98.4% of PCR positive patients and 83.3% of PCR negative patients were considered cured. The overall recurrence rate was very low (1.1%).Interpretation: Positive predictive value of the WHO clinical case definition was low. Low relapse rate confirms the efficacy of antibiotics. However, the need for and the best time for surgery for large Buruli ulcers requires clarification. We recommend confirmation by ZN stain at the rural health centers, since surgical intervention without delay may be necessary on the ZN positive cases to avoid progression of the disease. PCR negative patients were most likely not BU cases. Correct diagnosis and specific management of these non-BU ulcers cases are urgently needed.

O evolucionismo no ensino de Biologia: investigação das teorias de Lamarck e Darwin expostas nos livros didáticos de Biologia do Plano Nacional do Livro Didático do ensino médio - PNLEM

Pós-graduação em Educação - IBRC

Prescrições para ensinar a ensinar leitura e escrita na escola Normal de São Paulo: circulação de saberes pedagógicos Brasil/França (1874-1889)

Pós-graduação em Educação - FFC

O conceito de imitação na ópera francesa do século XVIII

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A influência da Segunda Guerra Mundial na produção literária de Saint- Exupéry

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise da teoria evolucionista nos livros didáticos do PNLD - 2012 na educação básica

A preocupação com o ensino da Evolução não é recente. Diversos pesquisadores fazem apontamentos de como é frequente nos livros de didáticos de biologia adotados no Brasil, a abordagem do tema como uma teoria acabada concluída e, desprovida de contextualização histórica para compreensão por parte dos alunos de como os conceitos foram desenvolvidos ao longo do tempo. Os pesquisadores relatam que a maior dificuldade dos alunos em compreender os conceitos ou a teoria da evolução está nos recorrentes equívocos conceituais e históricos presentes nos livros didáticos. Portanto, o presente trabalho tem por objetivo elaborar uma revisão bibliográfica, do que os teóricos especialistas na área do ensino de ciências têm apresentado sobre a Teoria da Evolução e o Ensino de Evolucionismo e qual tem sido a abordagem nos livros didáticos para o ensino público. A pesquisa constitui-se de análise bibliográfica, desenvolvida com base em material já elaborado, consultas em fontes bibliográficas do tipo: livros de leitura corrente de divulgação e publicações periódicas. Sendo a análise desse material de cunho qualitativo. A primeira etapa consistiu da escolha do tema e um levantamento preliminar do assunto. As etapas seguintes foram: o levantamento bibliográfico, a partir da problematização estabelecida, busca das fontes, leitura e fichamento do material. Para o fichamento dos livros didáticos o método utilizado foi fazê-lo em forma de registros. Foram feitos registros de seis coleções aprovadas PNDL de 2012: Bio. Lopes; Rosso, 2010. Biologia para a nova geração. Mendonça; Laurence, 2010. Biologia. Amabis; Martho, 2010. Biologia Hoje. Linhares; Gewandsnajder, 2010. Novas Bases da Biologia. Bizzo, 2010. Ser Protagonista Biologia. Santos; Aguilar; Oliveira, 2010. A partir desses registros foram feitos quadros comparativos... (Resumo completo, clicar acesso eletrônico abaixo)

Múltiplas imagens: a representação da mulher negra no Brasil

The aim of this paper is to present the readings, the reflections that have emerged, and, also, the results obtained by the search Multiple Images: The representation of black women in Brazil. The project aimed to find the black woman‟ images presented in historically constructed representations, for this was made a cut in images production of black people, choosing three artists, two works of each in three different historical moments, which according to the recanted the look of your time. The works and the artists were: Esclaves nègres, de différentes nations (1820-1830) e Negresses libres, vivant de leur travail (1820-1830) – Jean-Baptiste Debret; Baiana sambando (1926-1939) and Sambista descansando (1926-1939) – Cecília Meireles; Bastidores (1996) e Amas-de-leite (2008) – Rosana Paulino. The analysis of this corpus rests on the Reception Aesthetics and the Theory of Effect, searching the interaction between text and reader

O olhar como experiência: a pintura

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A harpa de pedais no século XVIII e as influências de suas características sobre seu repertório e escrita idiomática

Pós-graduação em Música - IA

Sincretismo cultural na joalheria afro-brasileira

Body adornment has been used as a ornament, ritualistic object, religious icon or as symbol demonstration of status and power in many different cultures. In Brazil, own visuality develops from the cultural syncretism. Thus, together with the mode of dress, the african-Brazilian jewelry acquires peculiarities derived from cultural identities that coexist. This paper proposes a look at africanBrazilian jewelry through visual representation in some works of Jean-Baptiste Debret - French painter member of the French Artistic Mission that registered objects and everyday scenes of slaves and freemen, of poor whites and aristocrats of Rio de Janeiro in the early nineteenth century. We are looking for jewelry as a historical record of lifestyles from a time and place with a social, economic and cultural local configuration.

Expanding the differential diagnosis of inherited neuropathies with non-uniform conduction: Andermann syndrome

Uniform conduction slowing has been considered a characteristic of inherited demyelinating neuropathies. We present an 18-year-old girl, born from first cousins, that presented a late motor and psychological development, cerebellar ataxia, facial diplegia, abnormal eye movement, scoliosis, and corpus callosum agenesis, whose compound muscle action potentials were slowed and dispersed. A mutation was found on KCC3 gene, confirming Andermann syndrome, a disease that must be included in the differential diagnosis of inherited neuropathies with non-uniform conduction slowing.

Galactose Recognition by the Apicomplexan Parasite Toxoplasma gondii

Toxosplasma gondii is the model parasite of the phylum Apicomplexa, which contains numerous obligate intracellular parasites of medical and veterinary importance, including Eimeria, Sarcocystis, Cryptosporidium, Cyclospora, and Plasmodium species. Members of this phylum actively enter host cells by a multistep process with the help of microneme protein (MIC) complexes that play important roles in motility, host cell attachment, moving junction formation, and invasion. T. gondii (Tg)MIC1-4-6 complex is the most extensively investigated microneme complex, which contributes to host cell recognition and attachment via the action of TgMIC1, a sialic acid-binding adhesin. Here, we report the structure of TgMIC4 and reveal its carbohydrate-binding specificity to a variety of galactose-containing carbohydrate ligands. The lectin is composed of six apple domains in which the fifth domain displays a potent galactose-binding activity, and which is cleaved from the complex during parasite invasion. We propose that galactose recognition by TgMIC4 may compromise host protection from galectin-mediated activation of the host immune system.