942 resultados para 060807 Animal Structure and Function
Resumo:
Evergreen Nothofagus betuloides and decidoues N. pumilo form the main forest types in Tierra del Fuego. These forest were sampled along two altitudinal gradients to study their structure and dynamics and assess the causes of their distribution.
Resumo:
Evergreen Nothofagus betuloides and decidoues N. pumilo form the main forest types in Tierra del Fuego. These forest were sampled along two altitudinal gradients to study their structure and dynamics and assess the causes of their distribution.
Resumo:
OBJECTIVES: The objective of this study was to evaluate associations between aortic pulse wave velocity (PWV) and aortic and carotid vessel wall thickness (VWT) using cardiovascular magnetic resonance imaging (MRI) in patients with hypertension as compared with healthy adult volunteers. MATERIALS AND METHODS: Local medical ethics approval was obtained and the participants gave informed consent. Fifteen patients with hypertension (5 men and 10 women; mean [SD] age, 49 [14] years) and 15 age- and sex-matched healthy volunteers were prospectively included and compared. All participants underwent MRI examination for measuring aortic and carotid VWT and aortic PWV with well-validated MRI techniques at 1.5- and 3-T MRI systems: PWV was assessed from velocity-encoded MRI and VWT was assessed by using dual-inversion black-blood gradient-echo imaging techniques. Paired t tests were used for testing differences between the volunteers and the patients and Pearson correlation (r) and univariable and multivariable stepwise linear regression analyses were used to test associations between aortic and carotid arterial wall thickness and stiffness. RESULTS: Mean values for aortic PWV and aortic and carotid VWT (indexed for body surface area [BSA]) were all significantly higher in patients with hypertension as compared with the healthy volunteers (ie, aortic PWV, 7.0 ± 1.4 m/s vs 5.7 ± 1.3 m/s; aortic VWT/BSA, 0.12 ± 0.03 mL/m vs 0.10 ± 0.03 mL/m; carotid VWT/BSA, 0.04 ± 0.01 mL/m vs 0.03 ± 0.01 mL/m; all P < 0.01). Aortic PWV was highly correlated with aortic VWT/BSA (r = 0.76 and P = 0.002 in the patients vs r = 0.63 and P = 0.02 in the volunteers), and in the patients, aortic PWV was moderately correlated with carotid VWT/BSA (r = 0.50; P = 0.04). In the volunteers, correlation between aortic PWV and carotid VWT/BSA was not significant (r = 0.40; P = 0.13). In addition, aortic VWT/BSA was significantly correlated with carotid VWT/BSA, in both the patients (r = 0.60; P = 0.005) and volunteers (r = 0.57; P = 0.007). CONCLUSIONS: In the patients with hypertension and the healthy volunteers, the aortic PWV is associated more strongly with aortic wall thickness than with carotid wall thickness, reflecting site-specific coupling between vascular wall thickness and function.
Resumo:
The formation and structural evolution of the jungrau syncline is described, based on excellent outcrops occurring in the lotschental, in the central alps of switzerland. the quality of the outcrops allows us to demonstrate that the external massifs of the swiss alps have developed due to internal folding. The jungfrau suncline, which separates the autochtonous gastern dome from the aar massif basement gneiss folds, is composed of slivers of basement rocks with their mesozoic sedimentary cover. in the inner faflertal, a side valley of the lotschental, the 200 m thick syncline cp, roses fpir imots, the gastern massif with a reduced mesozoic sedimentary cover in a normal stratigraphic succession, two units of overturned basement rocks with their mesozoic sedimentary cover, and the overturned lower limn of the tschingelhorn gneiss fold of the aar massif with lenses of its sedimentary cover. stratigraphy shows that the lower units, related to the gastern massis, are condensed and that the upper units, deposited farther away from a gastern paleo-high, form a more complete sequence, linked to the doldenhorn meso-cneozoic basin fill. the integration of these local observations with published regional data leads to the following model. on the northern margin of the doldenhorn hbasin, at the northern fringe of the alpine tethuys, the pre-triassic crystalline basement and its mesozoic sedimentary cover were folded by ductile deformation at temperatures above 300 degrees C and in the presence of high fluid pressures, as the helveti c and penninic nappes were overthrusted towards the northwest during the main alpine deformation phase, the visosity contrast between the basement gneisses and the sediments caused the formation of large basement anticlines and tight sedimentary sunclines (mullion-type structures). The edges of basement blocks bounded buy pre-cursor se-dipping normal faults at the northwestern border of the doldenhorn basin were deformed bu simple shear, creating overturned slices of crystalline rocks with their sedimentary cover in what now forms the hungfrau syncline. the localisation of ductile deformation in the vicinity of pre-existing se-dipping faults is thought to have been helped by the circulation of fluids along the faults; these fluids would have been released from the mesozoic sediments by metamorphic dehydration reactions accompanied by creep and dynamic recrystallisation of quartz at temperatures above 300 degrees C. Quantification of the deformation suggests an strain ellipsoid with a ratio (1 + e(1)/+ e(3)) of approximately 1000. The jungfrau suncline was deformed bu more brittle nw-directed shear creating well-developed shear band cleavages at a late stage, after cooling by uplift and erosion. It is suggested that the external massifs of the apls are basement gneiss folds created at temperatures of 300 degrees C by detachment through ductile deformation of the upper crust of the european plate as it was underthrusted below the adriatic plate.
Resumo:
Arising from either retrotransposition or genomic duplication of functional genes, pseudogenes are "genomic fossils" valuable for exploring the dynamics and evolution of genes and genomes. Pseudogene identification is an important problem in computational genomics, and is also critical for obtaining an accurate picture of a genome's structure and function. However, no consensus computational scheme for defining and detecting pseudogenes has been developed thus far. As part of the ENCyclopedia Of DNA Elements (ENCODE) project, we have compared several distinct pseudogene annotation strategies and found that different approaches and parameters often resulted in rather distinct sets of pseudogenes. We subsequently developed a consensus approach for annotating pseudogenes (derived from protein coding genes) in the ENCODE regions, resulting in 201 pseudogenes, two-thirds of which originated from retrotransposition. A survey of orthologs for these pseudogenes in 28 vertebrate genomes showed that a significant fraction ( approximately 80%) of the processed pseudogenes are primate-specific sequences, highlighting the increasing retrotransposition activity in primates. Analysis of sequence conservation and variation also demonstrated that most pseudogenes evolve neutrally, and processed pseudogenes appear to have lost their coding potential immediately or soon after their emergence. In order to explore the functional implication of pseudogene prevalence, we have extensively examined the transcriptional activity of the ENCODE pseudogenes. We performed systematic series of pseudogene-specific RACE analyses. These, together with complementary evidence derived from tiling microarrays and high throughput sequencing, demonstrated that at least a fifth of the 201 pseudogenes are transcribed in one or more cell lines or tissues.
Resumo:
Images of myocardial strain can be used to diagnose heart disease, plan and monitor treatment, and to learn about cardiac structure and function. Three-dimensional (3D) strain is typically quantified using many magnetic resonance (MR) images obtained in two or three orthogonal planes. Problems with this approach include long scan times, image misregistration, and through-plane motion. This article presents a novel method for calculating cardiac 3D strain using a stack of two or more images acquired in only one orientation. The zHARP pulse sequence encodes in-plane motion using MR tagging and out-of-plane motion using phase encoding, and has been previously shown to be capable of computing 3D displacement within a single image plane. Here, data from two adjacent image planes are combined to yield a 3D strain tensor at each pixel; stacks of zHARP images can be used to derive stacked arrays of 3D strain tensors without imaging multiple orientations and without numerical interpolation. The performance and accuracy of the method is demonstrated in vitro on a phantom and in vivo in four healthy adult human subjects.
Resumo:
Abstract
Resumo:
The 24-item Brief Psychiatric Rating Scale (BPRS, version 4.0) enables the rater to measure psychopathology severity. Still, little is known about the BPRS's reliability and validity outside of the psychosis spectrum. The aim of this study was to examine the factorial structure and sensitivity to change of the BPRS in patients with unipolar depression. Two hundred and forty outpatients with unipolar depression were administered the 24-item BPRS. Assessments were conducted at intake and at post-treatment in a Crisis Intervention Centre. An exploratory factor analysis of the 24-item BPRS produced a six-factor solution labelled "Mood disturbance", "Reality distortion", "Activation", "Apathy", "Disorganization", and "Somatization". The reduction of the total BPRS score and dimensional scores, except for "Activation", indicates that the 24-item BPRS is sensitive to change as shown in patients that appeared to have benefited from crisis treatment. The findings suggest that the 24-item BPRS could be a useful instrument to measure symptom severity and change in symptom status in outpatients presenting with unipolar depression.
Resumo:
Remorins form a superfamily of plant-specific plasma membrane/lipid-raft-associated proteins of unknown structure and function. Using specific antibodies, we localized tomato remorin 1 to apical tissues, leaf primordia and vascular traces. The deduced remorin protein sequence contains a predicted coiled coil-domain, suggesting its participation in protein-protein interactions. Circular dichroism revealed that recombinant potato remorin contains an alpha-helical region that forms a functional coiled-coil domain. Electron microscopy of purified preparations of four different recombinant remorins, one from potato, two divergent isologs from tomato, and one from Arabidopsis thaliana , demonstrated that the proteins form highly similar filamentous structures. The diameters of the negatively-stained filaments ranged from 4.6-7.4 nm for potato remorin 1, 4.3-6.2 nm for tomato remorin 1, 5.7-7.5 nm for tomato remorin 2, and 5.7-8.0 nm for Arabidopsis Dbp. Highly polymerized remorin 1 was detected in glutaraldehyde-crosslinked tomato plasma membrane preparations and a population of the protein was immunolocalized in tomato root tips to structures associated with discrete regions of the plasma membrane.
Resumo:
This study was carried out to assess the genetic variability of ten "cagaita" tree (Eugenia dysenterica) populations in Southeastern Goiás. Fifty-four randomly amplified polymorphic DNA (RAPD) loci were used to characterize the population genetic variability, using the analysis of molecular variance (AMOVA). A phiST value of 0.2703 was obtained, showing that 27.03% and 72.97% of the genetic variability is present among and within populations, respectively. The Pearson correlation coefficient (r) among the genetic distances matrix (1 - Jaccard similarity index) and the geographic distances were estimated, and a strong positive correlation was detected. Results suggest that these populations are differentiating through a stochastic process, with restricted and geographic distribution dependent gene flow.
Resumo:
Surface geological mapping, laboratory measurements of rock properties, and seismic reflection data are integrated through three-dimensional seismic modeling to determine the likely cause of upper crustal reflections and to elucidate the deep structure of the Penninic Alps in eastern Switzerland. Results indicate that the principal upper crustal reflections recorded on the south end of Swiss seismic line NFP20-EAST can be explained by the subsurface geometry of stacked basement nappes. In addition, modeling results provide improvements to structural maps based solely on surface trends and suggest the presence of previously unrecognized rock units in the subsurface. Construction of the initial model is based upon extrapolation of plunging surface. structures; velocities and densities are established by laboratory measurements of corresponding rock units. Iterative modification produces a best fit model that refines the definition of the subsurface geometry of major structures. We conclude that most reflections from the upper 20 km can be ascribed to the presence of sedimentary cover rocks (especially carbonates) and ophiolites juxtaposed against crystalline basement nappes. Thus, in this area, reflections appear to be principally due to first-order lithologic contrasts. This study also demonstrates not only the importance of three-dimensional effects (sideswipe) in interpreting seismic data, but also that these effects can be considered quantitatively through three-dimensional modeling.