1,893 research outputs found
Future Projections of Fire Occurrence in Brazil Using EC-Earth Climate Model
Fire has a fundamental role in the Earth system as it influences global and local ecosystem patterns and processes, such as vegetation distribution and structure, the carbon cycle and climate. Since, in the global context, Brazil is one of the regions with higher fire activity, an assessment is here performed of the sensitivity of the wildfire regime in Brazilian savanna and shrubland areas to changes in regional climate during the 21st Century, for an intermediate scenario (RCP4.5) of climate change. The assessment is based on a spatial and temporal analysis of a meteorological fire danger index specifically developed for Brazilian biomes, which was evaluated based on regional climate simulations of temperature, relative humidity and precipitation using the Rossby Centre Regional Climate Model (RCA4) forced by the EC-Earth earth system model. Results show a systematic increase in the extreme levels of fire danger throughout the 21st Century that mainly results from the increase in maximum daily temperature, which rises by about 2 °C between 2005 and 2100. This study provides new insights about projected fire activity in Brazilian woody savannas associated to climate change and is expected to benefit the user community, from governmental policies to land management and climate researches
Extracellular enolase of Candida albicans is involved in colonization of mammalian intestinal epithelium
Enolase is secreted by C. albicans and is present in its biofilms although its extracellular function is unknown. Here we show that extracellular enolase mediates the colonization of small intestine mucosa by C. albicans. Assays using intestinal mucosa disks show that C. albicans adhesion is inhibited, in a dose dependent mode, either by pretreatment of intestinal epithelium mucosa disks with recombinant C. albicans enolase (70% at 0.5 mg/ml enolase) or by pretreatment of C. albicans yeasts with anti-enolase antibodies (48% with 20 µg antiserum). Also using flow cytometry, immunoblots of conditioned media and confocal microscopy we demonstrate that enolase is present in biofilms and that the extracellular enolase is not an artifact due to cell lysis, but must represent functional secretion of a stable form. This is the first direct evidence that C. albicans extracellular enolase mediates colonization on its primary translocation site. Also, because enolase is encoded by a single locus in C. albicans, its dual role peptide, as glycolytic enzyme and extracellular peptide, is a remarkable example of gene sharing in fungi
Comparing Mixed & Integer Programming vs. Constraint Programming by solving Job-Shop Scheduling Problems
Scheduling is a key factor for operations management as well as for business success. From industrial Job-shop Scheduling problems (JSSP), many optimization challenges have emerged since de 1960s when improvements have been continuously required such as bottlenecks allocation, lead-time reductions and reducing response time to requests. With this in perspective, this work aims to discuss 3 different optimization models for minimizing Makespan. Those 3 models were applied on 17 classical problems of examples JSSP and produced different outputs. The first model resorts on Mixed and Integer Programming (MIP) and it resulted on optimizing 60% of the studied problems. The other models were based on Constraint Programming (CP) and approached the problem in two different ways: a) model CP1 is a standard IBM algorithm whereof restrictions have an interval structure that fail to solve 53% of the proposed instances, b) Model CP-2 approaches the problem with disjunctive constraints and optimized 88% of the instances. In this work, each model is individually analyzed and then compared considering: i) Optimization success performance, ii) Computational processing time, iii) Greatest Resource Utilization and, iv) Minimum Work-in-process Inventory. Results demonstrated that CP-2 presented best results on criteria i and ii, but MIP was superior on criteria iii and iv and those findings are discussed at the final section of this work
Ultrastructural characterization of porcine oocytes and adjacent follicular cells during follicle development : lipid component evolution
The objective of this study was to characterize the morphometry and ultrastructure of porcine preantral and antral follicles, especially the lipid component evolution. Ovarian tissue was processed for light microscopy. Ovarian tissue and dissected antral follicles (< 2, 2–4, and 4–6 mm) were also processed for transmission electron microscopy using routine methods and using an osmium-imidazole method for lipid detection. Primordial follicles (34 ± 5 μm in diameter, mean ± SD) had one layer of flattened-cuboidal granulosa cells around the oocyte, primary follicles (40 ± 7 μm) had a single layer of cuboidal granulosa cells around the oocyte, and secondary follicles (102 ± 58 μm) had two or more layers of cuboidal granulosa cells around the oocyte. Preantral follicle oocytes had many round mitochondria and both rough and smooth endoplasmic reticulum. In oocytes of primordial and primary follicles, lipid droplets were abundant and were mostly located at the cell poles. In secondary and antral follicles, the zona pellucida completely surrounded the oocyte, whereas some microvilli and granulosa cells projected through it. Numerous electron-lucent vesicles and vacuoles were present in the oolemma of secondary and antral follicles. Based on osmium-imidazole staining, most of these structures were shown to be lipid droplets. As the follicle developed, the appearance of the lipid droplets changed from small and black to large and gray, dark or dark with light streaks, suggesting that their nature may change over time. In summary, although porcine follicles and oocytes had many similarities to those of other mammalian species, they were rich in lipids, with lipid droplets with varying morphological patterns as the follicle developed
Perspectives of PV Microgeneration in Brazil: A Proposition of Regulation Enhancement Methodology
The solar photovoltaic (PV) generation is disseminating on multiple kinds of sites due to the energy market liberalization, the renewable energy sources subsidies policy, the decreasing of acquisition costs and the adaptability to different installation conditions. These factors allowed the growth of PV generation, especially in the distributed generation (DG) segment. Meanwhile, the development of a legal and regulatory apparatus became mandatory to assure benefits to DG-adopters, without causing damages to the utility grid, preventing technical failures and eventual excessive pricing to non-adopters. As the technology innovations impose new possibilities and the number of adopters grows exponentially, the challenges become more visible and a regulation update, urgent. In this context, this paper aims to review the current pricing model for DG in Brazil, focusing on PV microgeneration, and to propose a methodology based on the Delphi Method to enhance the most critical topics of the on-going regulation
Comparação da fauna de formigas de serapilheira entre área de floresta atlântica secundária e plantação adjacente de pinus no sudeste do Brasil
We investigated the influence of Pinus afforestation on the structure of leaf-litter ant communities in the southeastern Brazilian Atlantic Forest, studying an old secondary forest and a nearly 30 year-old never managed Pinus elliottii reforested area. A total of 12,826 individual ants distributed among 95 species and 32 genera were obtained from 50 1 m² samples/ habitat. Of these, 60 species were recorded in the pine plantation and 82 in the area of Atlantic forest; almost 50% of the species found in the secondary forest area were also present in the pine plantation. The number of species per sample was significantly higher in the secondary forest than in the pine plantation. Forest-adapted taxa are the most responsible for ant species richness differences between areas, and the pine plantation is richer in species classified as soil or litter omnivorous-dominants. The specialized ant predators registered in the pine plantation, as seven Dacetini, two Basiceros, two Attini and two Discothyrea, belong to widely distributed species. The NMDS (non-metric multidimensional scaling) ordination also suggested strong differences in similarity among samples of the two areas. Furthermore, this analysis indicated higher sample heterogeneity in the secondary forest, with two clusters of species, while in the pine plantation the species belong to a single cluster. We applied the ant mosaic hypothesis to explain the distribution of the leaf-litter fauna and spatial autocorrelation tests among samples. We argue that the results are likely related to differences in quality and distribution of the leaf-litter between the pine plantation and the secondary area.A influência do reflorestamento com Pinus na estrutura da fauna de formigas de serapilheira foi investigada, estudando uma floresta Atlântica secundária inalterada há 30 anos e uma área reflorestada com Pinus elliottii no Sudeste do Brasil. Em 50 amostras de 1 m² tomadas em cada área, foram coletados 12.826 indivÃduos, distribuÃdos em 95 espécies e 32 gêneros de formigas. Foram identificadas 60 espécies na área reflorestada com Pinus e 82 espécies na área de floresta secundária; aproximadamente 50% das espécies foram registradas nas duas áreas. A mediana do número de espécies por amostra foi maior na floresta secundária. Táxons com biologia especializada são responsáveis por grande parte das diferenças de composição de fauna, sendo a área de reflorestamento com Pinus mais rica em espécies onÃvoras e dominantes. Predadoras especializadas registradas na área de Pinus, como sete espécies de Dacetini, duas Basiceros, duas Attini e duas Discothyrea, têm ampla distribuição na Floresta Atlântica. A ordenação das amostras com o escalonamento multidimensional não-métrico (NMDS) indicou grande diferença na similaridade entre as amostras das áreas. Adicionalmente, essa análise sugere maior heterogeneidade na composição das amostras da floresta secundária, identificando dois agrupamentos de espécies, enquanto a área de Pinus apresenta um agrupamento apenas. Para investigar quais fatores podem explicar a heterogeneidade observada, testes de co-ocorrência e de autocorrelação espacial foram aplicados entre amostras de cada área. Nossa conclusão é que as diferenças observadas devem estar relacionadas com diferenças na qualidade e distribuição da serapilheira entre as áreas.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)UMC - Fundação de Amparo ao Ensino e Pesquis
Design and construction of a didactic standalone photovoltaic plant
This paper proposes the design and construction of a standalone didactic photovoltaic (PV) plant. The system components are available as a didactic kit to the students of the Federal Institute of Education, Science and Technology of Ceará (IFCE), Brazil. Thus, contributing to the teaching-learning process and providing a system to be used in future researches. In addition, the system was designed for supplying electricity to the lighting circuit of the Energy Processing Laboratory, located at IFCE Fortaleza Campus. The PV system developed during the work has an autonomy of 900 Ah and the total installed power of 840 Wp. Using a data capture system, a generation generated by the PV microgeneration was registered in operation up to 647 W
Cryopreservation of swine ovarian tissue : effect of different cryoprotectants on the structural preservation of preantral follicle oocytes
The present study aimed to test different cryoprotectants on cryopreservation of pig ovarian tissue. Pig ovaries (n = 3) were collected at a local slaughterhouse. From each ovary, ten cortex samples were taken. One was immediately fixed (control) and another placed in short-term tissue incubation (STTI control). The other 8 samples were cryopreserved, in pairs, using 4 different cryoprotectants: dimethyl sulphoxide (Me2SO – 1.5 M), ethylene glycol (EG – 1.5 M), propanediol (PROH – 1.5 M) and glycerol (GLY – 10%), all with 0.4% sucrose. Samples were slow cooled and stored in liquid nitrogen for 7 days. After thawing and cryoprotectant removal, one sample from each treatment was immediately fixed and the other was placed in short-term tissue incubation (STTI) for 2 h and then fixed. Samples were processed for histology and transmission electron microscopy. The percentages of morphologically normal follicles (MNF) in cryopreserved tissue using Me2SO (67.0 ± 4.9), EG (81.8 ± 1.4) and PROH (55.9 ± 9.9) were significantly lower (P < 0.05) than observed in fresh control tissue (97.7 ± 1.2). When ovarian tissue was cryopreserved with GLY, no morphologically normal follicles could be found (0%). After STTI, PROH showed a significantly lower percentage of MNF when compared with all other treatments and the control. After ultrastructural analysis, follicles cryopreserved with Me2SO and EG showed some small alterations, but no signs of advanced degeneration. Overall, these were similar to follicles from the control group. In conclusion, it is possible to cryopreserve preantral follicles from pig ovarian tissue using Me2SO or EG
Convolutamydine A and synthetic analogues have antinociceptive properties in mice
AbstractConvolutamydine A, an oxindole that originated from a marine bryozoan, has several biological effects. In this study, we aimed to investigate the antinociceptive effects of convolutamydine A and two new synthetic analogues.Convolutamydine A and the two analogues were given orally to assess their ability to induce antinociceptive effects. Formalin-induced licking response, acetic acid-induced contortions, and hot plate models were used to characterize the effects of convolutamydine A and its analogues.Convolutamydine A (4,6-bromo-3-(2-oxopropyl)-3-hydroxy-2-oxindole), compound 1 (3-(2-oxopropyl)-3-hydroxy-2-oxindole), and compound 2 (5-bromo-3-(2-oxopropyl)-3-hydroxy-2-oxindole) caused peripheral antinociceptive and anti-inflammatory effects in the acetic acid-induced contortions and the formalin-induced licking models. Supraspinal effects were also observed in the hot plate model and were similar to those obtained with morphine. The peripheral effects were not mediated by the cholinergic or opioid systems. The antinociceptive effects of convolutamydine A seem to be mediated by all three systems (cholinergic, opioid, and nitric oxide systems), and the mechanism of action of compounds 1 and 2 involved cholinergic and nitric oxide-mediated mechanisms. Convolutamydine A and its analogues (compounds 1 and 2) showed good antinociceptive ability after systemic administration in acute pain models. The antinociceptive action mediated by cholinergic, opioid, and nitric oxide systems could explain why convolutamydine A, compound 1, and compound 2 retained their antinociceptive effects. The doses used were similar to the doses of morphine and were much lower than that of acetylsalicylic acid, the classical analgesic and anti-inflammatory drug.In conclusion, convolutamydine A and the two analogues demonstrated antinociceptive effects comparable to morphine's effects
Chemical Composition and In Vitro Cytotoxic and Antimicrobial Activities of the Essential Oil from Leaves of Zanthoxylum monogynum St. Hill (Rutaceae).
Background: The Zanthoxylum monogynum species belongs to the family Rutaceae and is found in Southeast, Midwest, and Northeast Brazil. For this genus several biological activities have been described. Methods: The essential oil (EO) was obtained from the leaves of Zanthoxylum monogynum by hydro-distillation and was analyzed by gas chromatograph and gas chromatograph/mass spectrometry (GC and GC/MS). Also the EO of Z. monogynum was evaluated for in vitro cytotoxic activity against six tumor cell lines and for antimicrobial activity, performing disk diffusion and MIC assays with yeast and bacterial strains. Results: The chemical analysis afforded the identification of 18 components (99.0% of the EO). The major components were found to be citronellol (43.0%) and farnesol (32.0%). The in vitro cytotoxic activity against tumor cell lines, resulted in IC50 values ranging from 11-65 µg/mL against all tested cell lines. Antimicrobial activity of the essential oil was also tested and oil was effective, especially against Cryptococcus sp. yeast. All the tested yeast strains showed at least 90% growth inhibition. Conclusions: the essential oil from leaves of Z. monogynum has a different qualitative and quantitative composition when compared to the composition previously described. Also this EO has significant cytotoxic activity and moderate activity against Cryptococcus sp. and Saccharomyces cereviseae yeasts
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