90 research outputs found
Batalla de Tulcán
Documento extraido del "Diario de operaciones -año 1862- llevado por el jefe del Estado Mayor Genral, Sergio Arboleda
Valoracion de las diferencias diagnósticas radiográficas entre la posición natural de la cabeza y la posición inducida por los auriculares del cefalostato en la angulación craneocervical
ABSTRACT: For each patient there is a natural head position which responds to individual and environmental factors, like survival, independent from occlusion. The purpose of this study was to value the radiographic- diagnostic differences between lateral cephalometric radiographs taken in natural head position (NHP) and in a standard position with cephalostatic ear rods in the craneocervical angulation of each patient. Thirty patients were evaluated and two lateral cephalometric radiographs were taken for each subject, one in natural head position and the other in standard position with the cephalostatic ear rods. They were classified as biotype I, II, III according to their facial patterns and the ANB angle. The measurements were compared using both techniques and biotypes. The results showed statistical significant differences between both techniques on biotype III, but for biotype I and II the results were similar. It is suggested that the lateral cephalometric radiographs in the biotype III subjects be taken in natural head position.RESUMEN: Existe una posición natural para cada paciente respondiendo a muchos factores individuales y ambientales, como los de sobrevivencia, independiente de la oclusión. El propósito de este estudio fue valorar las diferencias diagnósticas radiográficas entre la posición natural de la cabeza (PNC) y la posición inducida por los auriculares del cefalostato en la angulación craneocervical. Se evaluaron treinta pacientes, a quienes se les tomó dos radiografías cefálicas laterales, en posición natural de la cabeza y con cefalostato. Se clasificaron en los biotipos I, II y III según sus características faciales y el ángulo ANB. Se compararon las mediciones angulares entre ambas técnicas y para cada biotipo. Los resultados mostraron diferencias estadísticas significativas entre ambas técnicas de toma radiográfica para el biotipo III, mientras que en los biotipos I y II ambas técnicas mostraron resultados similares. En los sujetos con biotipo III se sugiere tomar la radiografía cefálica lateral en PNC
Recommended from our members
Rarity of monodominance in hyperdiverse Amazonian forests.
Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors
Hepatitis B Virus infection in HIV-positive population in Brazil: results of a survey in the state of Mato Grosso and a comparative analysis with other regions of Brazil
BACKGROUND: End-stage liver disease is currently a major concern among HIV-positive individuals due to co-infection with hepatotropic virus. Hepatitis C has been pointed out as a remarkable factor for that. More recently, hepatitis B virus (HBV) infection has also been found to play a role on liver disease in this population. HIV-HBV co-infection prevalence remains largely unknown in vast areas of Brazil. The objective of the present study was to estimate the prevalence of HBV and HDV infection in HIV-infected subjects living in the state of Mato Grosso, in the Central region of Brazil, and compare it to other Brazilian studies. We also assess epidemiologic data regarding risk factors and vaccinal status. METHODS: HIV-positive individuals followed at the Central Laboratory of the Department of Public Health of Mato Grosso in the city of Cuiabá composed the sample. Participants answered a specific questionnaire and had a blood sample taken and tested for serologic markers. RESULTS: A thousand individuals were interviewed and tested for HBsAg, anti-HBc, anti-HBs and anti-HDV if positive for HBsAg. Measurements of CD4 and viral load for HIV-1 were also performed. Overall prevalence of HBV exposure (anti-HBc +ve) was 40.0%, and 3.7% for HBsAg. This prevalence data was similar or slightly lower than for other Brazilian regions, which ranged from 40% and 3% to 71% and 24%, respectively. Testing for anti-HDV in the 37 HBsAg positive patients was positive in only one subject. Factors that showed independent association with HBV exposure, after adjustment, were: male gender, older age groups, tattooing, and reporting more than ten sexual partners throughout life (p < 0.01). Eighty-one (27.5%) out of 291 HBV-unexposed individuals who reported vaccination were anti-HBs positive. Anti-HBs prevalence was higher among those who had higher levels of CD4 by multivariate analysis. CONCLUSION: Our data showed HBV infection prevalence similar or slightly lower than that reported in other regions of Brazil. In addition, our data revealed a less important role for drug injection in the spread of HIV and HBV in Mato Grosso compared to other regions of the country. The high rate of non-vaccinated subjects among this HBV-unexposed, HIV-infected population is a matter of considerable health concern in this region. The relationship between CD4 levels and HBV vaccine response found in the present study reinforces the need of keeping health care workers alert to this issue
The Maristán stigma scale: a standardized international measure of the stigma of schizophrenia and other psychoses
Background:
People with schizophrenia face prejudice and discrimination from a number of sources including professionals and families. The degree of stigma perceived and experienced varies across cultures and communities. We aimed to develop a cross-cultural measure of the stigma perceived by people with schizophrenia.Method:
Items for the scale were developed from qualitative group interviews with people with schizophrenia in six countries. The scale was then applied in face-to-face interviews with 164 participants, 103 of which were repeated after 30 days. Principal Axis Factoring and Promax rotation evaluated the structure of the scale; Horn’s parallel combined with bootstrapping determined the number of factors; and intra-class correlation assessed test-retest reliability.Results:
The final scale has 31 items and four factors: informal social networks, socio-institutional, health professionals and self-stigma. Cronbach’s alpha was 0.84 for the Factor 1; 0.81 for Factor 2; 0.74 for Factor 3, and 0.75 for Factor 4. Correlation matrix among factors revealed that most were in the moderate range [0.31-0.49], with the strongest occurring between perception of stigma in the informal network and self-stigma and there was also a weaker correlation between stigma from health professionals and self-stigma. Test-retest reliability was highest for informal networks [ICC 0.76 [0.67 -0.83]] and self-stigma [ICC 0.74 [0.64-0.81]]. There were no significant differences in the scoring due to sex or age. Service users in Argentina had the highest scores in almost all dimensions.Conclusions:
The MARISTAN stigma scale is a reliable measure of the stigma of schizophrenia and related psychoses across several cultures. A confirmatory factor analysis is needed to assess the stability of its factor structure.We are also grateful for support from the Pan-American Health Office (PAHO), Camden and Islington NHS Foundation Trust and University College London (UCL)
Local hydrological conditions influence tree diversity and composition across the Amazon basin
Tree diversity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well-drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree diversity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1-ha non-flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha diversity, 2) the community-weighted wood density mean (CWM-wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree diversity depends on climate, being more evident in wetter forests, where diversity increases towards locations with well-drained soils. CWM-wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central-Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the diversity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures
Mapping density, diversity and species-richness of the Amazon tree flora
Using 2.046 botanically-inventoried tree plots across the largest tropical forest on Earth, we mapped tree species-diversity and tree species-richness at 0.1-degree resolution, and investigated drivers for diversity and richness. Using only location, stratified by forest type, as predictor, our spatial model, to the best of our knowledge, provides the most accurate map of tree diversity in Amazonia to date, explaining approximately 70% of the tree diversity and species-richness. Large soil-forest combinations determine a significant percentage of the variation in tree species-richness and tree alpha-diversity in Amazonian forest-plots. We suggest that the size and fragmentation of these systems drive their large-scale diversity patterns and hence local diversity. A model not using location but cumulative water deficit, tree density, and temperature seasonality explains 47% of the tree species-richness in the terra-firme forest in Amazonia. Over large areas across Amazonia, residuals of this relationship are small and poorly spatially structured, suggesting that much of the residual variation may be local. The Guyana Shield area has consistently negative residuals, showing that this area has lower tree species-richness than expected by our models. We provide extensive plot meta-data, including tree density, tree alpha-diversity and tree species-richness results and gridded maps at 0.1-degree resolution
Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates
Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis).
Time period: Tree-inventory plots established between 1934 and 2019.
Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm.
Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield.
Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes.
Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests.
Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types
Geography and ecology shape the phylogenetic composition of Amazonian tree communities
AimAmazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.ResultsIn the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions
- …