152 resultados para Unitary similarity


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Introduction: In past decades, leishmaniasis burden has been low across Egypt; however, changing environment and land use has placed several parts of the country at risk. As a consequence, leishmaniasis has become a particularly difficult health problem, both for local inhabitants and for multinational military personnel. Methods: To evaluate coarse-resolution aspects of the ecology of leishmaniasis transmission, collection records for sandflies and Leishmania species were obtained from diverse sources. To characterize environmental variation across the country, we used multitemporal Land Surface Temperature (LST) and Normalized Difference Vegetation Index (NDVI) data from the Moderate Resolution Imaging Spectroradiometer (MODIS) for 2005-2011. Ecological niche models were generated using MaxEnt, and results were analyzed using background similarity tests to assess whether associations among vectors and parasites (i.e., niche similarity) can be detected across broad geographic regions. Results: We found niche similarity only between one vector species and its corresponding parasite species (i.e., Phlebotomus papatasi with Leishmania major), suggesting that geographic ranges of zoonotic cutaneous leishmaniasis and its potential vector may overlap, but under distinct environmental associations. Other associations (e.g., P. sergenti with L. major) were not supported. Mapping suitable areas for each species suggested that northeastern Egypt is particularly at risk because both parasites have potential to circulate. Conclusions: Ecological niche modeling approaches can be used as a first-pass assessment of vector-parasite interactions, offering useful insights into constraints on the geography of transmission patterns of leishmaniasis.

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Introduction Over the last recent years, the number of Q fever cases have has increased throughout the world. An epidemiological investigation was performed in the area in which the first molecular documentation of Q fever in Brazil was previously reported. Methods Indirect immunofluorescence assay (IFA) and PCR of Coxiella burnetii targeting the htpAB gene were performed in samples from 14 dogs (blood); 1 cat (blood); 10 goats (blood, milk, vaginal swab and anal swab); 3 sheep (blood); and 2 horses (blood). Results Two dogs, two sheep and five goats were seroreactive. DNA was amplified from 6 milk and 2 blood samples from goats and from dogs, respectively. The sequence of the amplicons exhibited 99% sequence similarity with the homologous sequence of the htpAB gene of C. burnetii RSA 331 (GenBank - CP000890). Conclusions The results confirm C. burnetii infection in animals in Rio de Janeiro and reinforce the need for the surveillance of Q fever in Brazil.

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INTRODUCTION: Dengue is the most prevalent arboviral disease in tropical areas. In Mato Grosso, outbreaks are reported every year, but studies on dengue in this state are scarce. METHODS: Natural transovarial infection of Aedes aegypti by a flavivirus was investigated in the Jardim Industriário neighborhood of Cuiabá, Mato Grosso. Eggs were collected with ovitraps during the dry, intermediate, and rainy seasons of 2012. After the eggs hatched and the larvae developed to adulthood, mosquitoes (n = 758) were identified and allocated to pools of 1-10 specimens according to the collection location, sex, and climatic period. After RNA extraction, multiplex semi-nested RT-PCR was performed to detect the four dengue virus (DENV) serotypes, yellow fever virus, West Nile virus and Saint Louis encephalitis virus. RESULTS: DENV-4 was the only flavivirus detected, and it was found in 8/50 pools (16.0%). Three of the positive pools contained females, and five contained males. Their nucleotide sequences presented 96-100% similarity with DENV-4 genotype II strains from Manaus, Amazonas. The minimum infection rate was 10.5 per 1000 specimens, and the maximum likelihood estimator of the infection rate was 11.6 (95% confidence interval: 4.8; 23.3). CONCLUSIONS: This study provides the first evidence of natural transovarial infection by DENV-4 in Ae. Aegypti in Mato Grosso, suggesting that this type of infection might serve as a mechanism of virus maintenance during interepidemic periods in Cuiabá, a city where dengue epidemics are reported every year. These results emphasize the need for efficient vector population control measures to prevent arbovirus outbreaks in the state.

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Abstract: INTRODUCTION Characterization of Mycobacterium tuberculosis (MTB) isolates by DNA fingerprinting has contributed to tuberculosis (TB) control. The aim of this study was to determine the genetic diversity of MTB isolates from Tehran province in Iran. METHODS MTB isolates from 60 Iranian and 10 Afghan TB patients were fingerprinted by standard IS6110-restriction fragment length polymorphism (RFLP) analysis and spoligotyping. RESULTS The copy number of IS6110 ranged from 10-24 per isolate. The isolates were classified into 22 clusters showing ≥ 80% similarity by RFLP analysis. Fourteen multidrug-resistant (MDR) isolates were grouped into 4 IS6110-RFLP clusters, with 10 isolates [71% (95% CI: 45-89%)] in 1 cluster, suggesting a possible epidemiological linkage. Eighteen Iranian isolates showed ≥ 80% similarity with Afghan isolates. There were no strains with identical fingerprints. Spoligotyping of 70 isolates produced 23 distinct patterns. Sixty (85.7%) isolates were grouped into 13 clusters, while the remaining 10 isolates (14.2%) were not clustered. Ural (formerly Haarlem4) (n = 22, 31.4%) was the most common family followed by Central Asian strain (CAS) (n = 18, 25.7%) and T (n = 9, 12.8%) families. Only 1strain was characterized as having the Beijing genotype. Among 60 Iranian and 10 Afghan MTB isolates, 25% (95% CI: 16-37) and 70% (95% CI: 39-89) were categorized as Ural lineage, respectively. CONCLUSIONS A higher prevalence of Ural family MTB isolates among Afghan patients than among Iranian patients suggests the possible transmission of this lineage following the immigration of Afghans to Iran.

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OBJECTIVE: To investigate and characterize the professional stereotypes associated with general medicine and surgery among Brazilian medical residents. METHODS: A randomized sample of residents of the General Medicine and Surgery Residence Programs were interviewed and their perceptions and views of general and surgical doctors were compared. RESULTS: The general practitioner was characterized by the residents in general to be principally a sensitive and concerned doctor with a close relationship with the patient; (45%); calm, tranquil, and balanced (27%); with intellectual skills (25%); meticulous and attentive to details (23%); slow to resolve problems and make decisions (22%); and working more with probabilities and hypotheses (20%). The surgeon was considered to be practical and objective (40%); quickly resolving problems (35%); technical with manual skills (23%); omnipotent, arrogant, and domineering (23%); anxious, stressed, nervous, and temperamental (23%); and more decided, secure, and courageous (20%). Only the residents of general medicine attributed the surgeon with less knowledge of medicine and only the surgeons attributed gender characteristics to their own specialty. CONCLUSION: There was considerable similarity in the description of a typical general practitioner and surgeon among the residents in general, regardless of the specialty they had chosen. It was interesting to observe that these stereotypes persist despite the transformations in the history of medicine, i.e. the first physicians (especially regarding the valorization of knowledge) and the first surgeons, so-called "barber surgeons" in Brazil (associated with less knowledge and the performance of high-risk procedures).

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Fossils of wood, bone and teeth found along the Upper Purus River οf Amazonia. were studied using conventional microscopy and scanning electron microscopy. Mass spectometry was also used to investigate minor and trace element signatures of bone samples.The microsopy studies showed that there was little alteration of original textures. In the fossil wood samples, identified In thin section as tropical hardwood trees, the replacement of the original material with siderite suggests that fossilization occured in shallow sediments in which interstitial waters were saturated with respect to iron carbenate. In samples of both fossilized bone and wood, precipitation of secondary iron phases was commonly observed in cracks and voids. Other secondary phases Included silica, iron oxides, manganese carbonate. The intimate assοciation οf these secondary phases with the original biological structures could be evidence for a microbiological role in the formation of these phases. The similarity in rare earth element (REE) signatures for 2 fossil bone samples from different modern locations indicates their having shared similar diagenetic histories.The virtually complete preservation of original textures suggests that microscοpic studies could be useful in classifying fossil and even in identifying original materials. Rare carth signatures in fossilized bone may reflect ground water compositions at the time of fossilization.

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A large-scale inventory of trees > 10cm DBH was conducted in the upland "terra firme" rain forest of the Distrito Agropecuário da SUFRAMA (Manaus Free Zone Authority Agricultural District) approximately 65Km north of the city of Manaus (AM), Srasil. Thegeneral appearance and structure of the forest is described together with local topography and soil texture. Thepreliminary results of the Inventory provide a minimum estimate of 698 tree species in 53 families in the 40Km radius sampled, including 17 undescribed species. Themost numerically abundant families, Lecythidaceae, Leguminosae, 5apotaceae and Burseraceae as also among the most species rich families. One aspect of this diverse assemblage is the proliferation of species within certain genera, Including 26 genera In 17 families with 6 or more species or morphospecies. Most species have very low abundances of less than 1 tree per hectare. While more abundant species do exist at densities ranging up to a mean of 12 trees per ha, many have clumped distributions leading to great variation in local species abundance. The degree of similarity between hectare samples based int the Coefficient of Community similarity Index varies widely over different sample hectares for five ecologically different families. Soil texture apparently plays a significant role In determining species composition in the different one hectare plots examined while results for other variable were less consistent. Greater differences in similarity indices are found for comparisons with a one hectare sample within the same formation approximately 40Km to the south. It is concluded that homogeneity of tree community composition within this single large and diverse yet continuous upland forest formation can not be assumed.

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A preliminary survey of the spider fauna in natural and artificial forest gap formations at “Porto Urucu”, a petroleum/natural gas production facility in the Urucu river basin, Coari, Amazonas, Brazil is presented. Sampling was conducted both occasionally and using a protocol composed of a suite of techniques: beating trays (32 samples), nocturnal manual samplings (48), sweeping nets (16), Winkler extractors (24), and pitfall traps (120). A total of 4201 spiders, belonging to 43 families and 393 morphospecies, were collected during the dry season, in July, 2003. Excluding the occasional samples, the observed richness was 357 species. In a performance test of seven species richness estimators, the Incidence Based Coverage Estimator (ICE) was the best fit estimator, with 639 estimated species. To evaluate differences in species richness associated with natural and artificial gaps, samples from between the center of the gaps up to 300 meters inside the adjacent forest matrix were compared through the inspection of the confidence intervals of individual-based rarefaction curves for each treatment. The observed species richness was significantly higher in natural gaps combined with adjacent forest than in the artificial gaps combined with adjacent forest. Moreover, a community similarity analysis between the fauna collected under both treatments demonstrated that there were considerable differences in species composition. The significantly higher abundance of Lycosidae in artificial gap forest is explained by the presence of herbaceous vegetation in the gaps themselves. Ctenidae was significantly more abundant in the natural gap forest, probable due to the increase of shelter availability provided by the fallen trees in the gaps themselves. Both families are identified as potential indicators of environmental change related to the establishment or recovery of artificial gaps in the study area.

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The high tree diversity and vast extent of Amazonian forests challenge our understanding of how tree species abundance and composition varies across this region. Information about these parameters, usually obtained from tree inventories plots, is essential for revealing patterns of tree diversity. Numerous tree inventories plots have been established in Amazonia, yet, tree species composition and diversity of white-sand and terra-firme forests of the upper Rio Negro still remain poorly understood. Here, we present data from eight new one-hectare tree inventories plots established in the upper Rio Negro; four of which were located in white-sand forests and four in terra-firme forests. Overall, we registered 4703 trees > 10 cm of diameter at breast height. These trees belong to 49 families, 215 genera, and 603 species. We found that tree communities of terra-firme and white-sand forests in the upper Rio Negro significantly differ from each other in their species composition. Tree communities of white-sand forests show a higher floristic similarity and lower diversity than those of terra-firme forests. We argue that mechanisms driving differences between tree communities of white-sand and terra-firme forests are related to habitat size, which ultimately influences large-scale and long-term evolutionary processes.

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Lakes play an important role in biogeochemical, ecological and hydrological processes in the river-floodplain system. The aim of this study was to evaluate the dynamics of the limnological conditions of Catalão Lake, an Amazon floodplain lake. Thus, some of the main limnological environment variables (O2, temperature, pH, nutrient, electrical conductivity) of the Catalão Lake were analyzed under temporal and spacial scales. The study was conducted between November/2004 and August/2005. Sampling excursion were carried out every three months; one excursion for each of the four different hydrological periods (low water, rising water, high water and falling water). Sampling points were chosen so that it could be obtained a gradient of the distance from Negro River. Limnological profiles in Catalão Lake showed generally acidic to slightly alcaline water, with low levels of dissolved oxygen and low concentrations of soluble reactive phosphorous. The Negro River seems to exert the main influence during the rising water period, while the Solimões River is the principal controlling river during peak water. The Principal Component Analysis (PCA) grouped the seasonal collections by hydrological period, showing the formation of a north-south spatial gradient within the lake in relation to the limnological variables. Multivariate dispersion analysis based on distance-to-centroid method demonstrated an increase in similarity over the course of the hydrological cycle, as the lake was inundated in response to the flood pulse of the main river channels. However, the largest spatial homogeneity in the lake was observed in the epilimnion layer, during the falling water period. The daily analysis of variation indicated an oligomitic pattern during the years in which the lake was permanently connected to the Negro River. Although Catalão Lake receives large quantities of both black water from the Negro River and sediment-filled water from the Solimões River, the physical and chemical characteristics of the lake are more similar to those of the Solimões (várzea lake) than the Negro (blackwater lake).

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Phlebotomine sand flies are insects of medical importance. Species in the Neotropical region are highly diverse. Some of these species are considered cryptic species because of their morphological similarity between adult females of different species make identification especially difficult. The aim of this study was to analyze and describe the armature in the genital atrium (AGA) of some adult female sand flies, in order to discover new taxonomic characters that make it possible to distinguish between species that would otherwise be treated as cryptic by analysis of the AGA. The AGA of 16 Phlebotomine sand fly species are described. Distinct differences were found in relation to the shape and size of the armature, the presence or absence of spines on the armature, and the shape, size, and grouping patterns of the spines. These characters made it possible to distinguish between the species studied.

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Field collection and herbaria data did not allow to quantify the diversity of aquatic plants from Northern Brazil, so we could not detect biogeographic patterns. Therefore, our objectives were to identify and quantify the aquatic macrophytes of North Brazilian states, analyzing herbaria data plataforms (SpeciesLink and Flora do Brasil). The checklist was produced by bibliographic search (articles published between 1980 and 2000), herbaria collections of the platforms SpeciesLink and Flora do Brasil and field expeditions, where we utilized asystematic sampling. We also analyzed the floristic similarity of aquatic macrophytes among Northern Brazil, wetlands of distinct Brazilian regions and the Neotropics. We recorded 539 species, of which 48 are endemic to Brazil. The states with highest number of species were Amazonas and Pará, independently on platform. The most represented families were Poaceae (89 species), Podostemaceae (55), Cyperaceae (50) and Fabaceae (47). We highlight the unprecedent richness of Podostemaceae, due to our own field collection efforts on favorable habitats, 25 species being endemic. Emergent and/or amphibious plants (515) were dominant in total species richness and were best represented in lotic habitats. We found significant differences in richness and floristics among states, obtained from the platforms. There is floristic similarity among Northern states and other Brazilian wetlands. In conclusion, we observed a rich aquatic flora in Northern Brazil, in spite of scarcity of records for Acre, Rondonia and Tocantins; we highlight the unprecedent number of endemic species of Podostemaceae (25) and contrasting richness between SpeciesLink and Flora do Brasil.

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ABSTRACT The analysis of changes in species composition and vegetation structure in chronosequences improves knowledge on the regeneration patterns following land abandonment in the Amazon. Here, the objective was to perform floristic-structural analysis in mature forests (with/without timber exploitation) and secondary successions (initial, intermediate and advanced vegetation regrowth) in the Tapajós region. The regrowth age and plot locations were determined using Landsat-5/Thematic Mapper images (1984-2012). For floristic analysis, we determined the sample sufficiency and the Shannon-Weaver (H'), Pielou evenness (J), Value of Importance (VI) and Fisher's alpha (α) indices. We applied the Non-metric Multidimensional Scaling (NMDS) for similarity ordination. For structural analysis, the diameter at the breast height (DBH), total tree height (Ht), basal area (BA) and the aboveground biomass (AGB) were obtained. We inspected the differences in floristic-structural attributes using Tukey and Kolmogorov-Smirnov tests. The results showed an increase in the H', J and α indices from initial regrowth to mature forests of the order of 47%, 33% and 91%, respectively. The advanced regrowth had more species in common with the intermediate stage than with the mature forest. Statistically significant differences between initial and intermediate stages (p<0.05) were observed for DBH, BA and Ht. The recovery of carbon stocks showed an AGB variation from 14.97 t ha-1 (initial regrowth) to 321.47 t ha-1 (mature forests). In addition to AGB, Ht was also important to discriminate the typologies.

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Ecological studies were conducted in the ichthyofauna of Cedro, a small headwater stream located in a degraded area of State of São Paulo, Brazil, situated in the upper Paraná River basin. These are the results of two non-consecutive years observations and collections in two biotopes of that stream: a pool and a rapid. The ecological characteristics studied change in space and time. The present richness of species is high (21 species), nine of which are constant, six accessory and six accidental. The diversity is low (0.69 to 2.38), and the numeric predominance, from one to three species, occurred in both biotopes. The most frequent species are Poecilia reticulata (Peters, 1859) (28.1%), Corydoras cf. aeneus (Gill, 1858) (20.3%) and Hypostomus cf. ancistroides (Ihering, 1911) (19.8%). The density ranges from 0.7 to 19.8 specimens/m³. The similarity index indicates high similarity between the ichthyofauna (45.0% to 95.0%) inside the same or contiguous biotopes. The evenness (0.46 to 1.0) is comparable to those found in similar studies carried out in other streams.

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To estimate the populational fluctuation of Chrysomya Robineau-Desvoidy, 1830 species and the relation of populational abundance around, six wind oriented trap (WOT) were placed in three distinct ecological areas (urban, rural and wild) in Pelotas, Rio Grande do Sul, Brazil, from February/1993 to January/1995. The flies were weekly collected. Captured species were Chrysomya albiceps Wiedmann, 1819, C. megacephala Fabricius, 1794 and C. putoria Wiedmann, 1830 with respective abundance of 64.5%, 19.7% and 0.9%, representing a total of 85.0% of 409,920 specimens of Calliphoridae. The three species demonstrated similarity in the populational fluctuation, except in the abundance. The populational peak ocurred in autum when the temperature decreases. In the months of July to November no fly was collected, recomposing the population in December, when the temperature surpassed 20ºC.