1000 resultados para LOCAL KINEMATICS
Resumo:
Exploratory research reported in this paper was undertaken in Adelaide, Australia during 1998/99. The purpose of the research is to explore local development practice as evidenced through the experiences and actions of local citizens, community based groups and local government (Neuman, 1994). Results from this first stage research suggest that sustainability initiatives in Australia might best be implemented through a collaborative approach at the local community level involving local citizens working in partnership with local government. Copyright (C) 2002 John Wiley & Sons, Ltd and ERP Environment.
Resumo:
Advantages of dispersal on the scales that are possible in a long pelagic larval period are not apparent, even for benthic species. An alternative hypothesis is that wide dispersal may be an incidental byproduct of an ontogenetic migration from and then back to the parental habitat. Under this hypothesis, the water column is a better habitat than the bottom for early development. Because the parental area is often an especially favorable habitat for juveniles and adults, selection may even favor larval retention or larval return rather than dispersal. Where larval capabilities and currents permit, a high percentage of recruits may then be produced from local adults. Expected consequences of a high proportion of local recruitment are stronger links between stock and recruitment, greater vulnerability to recruitment overfishing and local modifications of habitat, greater local benefits from fishery reserves, and possibly more localized adaptation within populations. Export of some larvae is consistent with a high proportion of retained or returning larvae, could stabilize populations linked by larval exchange, and provide connectivity between marine reserves. Even a small amount of larval export could account for the greater gene flow, large ranges, and long evolutionary durations seen in species with long pelagic larval stages.
Resumo:
In this study we report the results of two experiments on visual attention conducted with patients with early-onset schizophrenia. These experiments investigated the effect of irrelevant spatial-scale information upon the processing of relevant spatial-scale information, and the ability to shift the spatial scale of attention, across consecutive trials, between different levels of the hierarchical stimulus. Twelve patients with early-onset schizophrenia and matched controls performed local-global tasks under: (1) directed attention conditions with a consistency manipulation and (2) divided-attention conditions. In the directed-attention paradigm, the early-onset patients exhibited the normal patterns of global advantage and interference, and were not unduly affected by the consistency manipulation. Under divided-attention conditions, however, the early-onset patients exhibited a local-processing deficit. The source of this local processing deficit lay in the prolonged reaction time to local targets, when these had been preceded by a global target, but not when preceded by a local target. These findings suggest an impaired ability to shift the spatial scale of attention from a global to a local spatial scale in early-onset schizophrenia. (C) 2003 Elsevier Science (USA). All rights reserved.
Resumo:
This paper describes the kinematics and muscle activity associated with the standard sit-up, as a first step in the investigation of complex motor coordination. Eight normal human subjects lay on a force table and performed at least 15 sit-ups, with the arms across the chest and the legs straight and unconstrained. Several subjects also performed sit-ups with an additional weight added to the head. Support surface forces were recorded to calculate the location of the center of pressure and center of gravity; conventional motion analysis was used to measure segmental positions; and surface EMG was recorded from eight muscles. While the sit-up consists of two serial components, 'trunk curling' and 'footward pelvic rotation', it can be further subdivided into five phases, based on the kinematics. Phases I and II comprise trunk curling. Phase I consists of neck and upper trunk flexion, and phase II consists of lumbar trunk lifting. Phase II corresponds to the point of peak muscle contraction and maximum postural instability, the 'critical point' of the sit-up. Phases III-V comprise footward pelvic rotation. Phase III begins with pelvic rotation towards the feet. phase W with leg lowering, and phase V with contact between the legs and the support surface. The overall pattern of muscle activity was complex with times of EMG onset, peak activity, offset, and duration differing for different muscles. This complex pattern changed qualitatively from one phase to the next, suggesting that the roles of different muscles and, as a consequence, the overall form of coordination, change during the sit-up. (C) 2003 Elsevier Science Ltd. All rights reserved.
Resumo:
There has been growing interest in the effects of variation in larval quality on the post-larval performance of adult marine invertebrates. Variation in egg/larval size is an obvious source of variation in larval quality but sources of variation have received little attention. For broadcast spawners, larval size may vary according to the local sperm environment but the generality of this result is unclear. Here, we show that, for a solitary ascidian, a polychaete and an echinoid, larval size is affected by the concentration of sperm present during fertilization. Larvae that are produced at high sperm concentrations are smaller than larvae that are produced from eggs exposed to low sperm concentrations. We also show that for three ascidians and an asteroid, egg size increases with maternal body size. These differences in larval size are likely to affect larval and subsequent adult performance in the field. Given that sperm concentrations in the field can fluctuate widely, it is likely that larval quality in free-spawning marine invertebrates will also vary widely.
Resumo:
The influence of the preparation method on the structural properties of the RuO(2)-Ta(2)O(5) system was investigated. Both thin films on Ti substrates and powder samples of nominal composition Ti/RuO(2)-Ta(2)O(5) (Ru:Ta = 100:0, 90:10, 80:20, 30:70, and 0:100 at.%) were prepared through thermal decomposition of polymeric precursors (DPP). The thin films and powder samples were investigated using X-ray absorption spectroscopy (XAS). XANES analyses showed that Ru and Ta are present in the Ru(IV) and Ta(V) oxidation states. EXAFS signals of all the samples were analyzed, to obtain the average bond length (r), coordination number, and the Debye-Waller factor (sigma(2)) for each Ru-O, Ru-Ru, Ta-O nearest-neighbor. The first shell Ru-O distance was found at 1.91-1.92 angstrom with coordination number of 1.8-2.1, and at 2.01-2.02 angstrom with coordination number of 3.9-4.1. The Ta-O distance obtained for all the samples and in both modes (transmission and fluorescence) had significantly different values from the theoretical ones. The results revealed that the local structure around both the Ru and Ta sites are similar, and that they consist of distorted M-O(6) octahedra (where M = Ru or Ta). (C) 2010 Elsevier B.V. All rights reserved.
Resumo:
Aims: It has long been demonstrated that epidermal growth factor (EGF) has catabolic effects oil bone. Thus. we examined the role of EGF in regulating mechanically induced bone modeling in a rat model of orthodontic tooth movement. Main methods: The maxillary first molars of rats were moved mesially using an orthodontic appliance attached to the maxillary incisor teeth. Rats were randomly divided into 4 groups: (G1) administration of PBS (Phosphate buffer saline Solution (n = 24); (G2) administration of empty liposomes (it = 24): (Q) administration 20 rig of EGF Solution (n = 24): and (G4) 20 ng of EGF-liposomes Solution (it = 24). Each Solution was injected in the mucosa of the left first molar adjacent to the appliance. At days 5, 10, 14 and 2 1 after drug administration. 6 animals of each group were sacrificed. Histomorphometric analysis was used to quantify osteoclasts (Tartrate-resistant acid phosphatase (TRAP) + cells) and tooth movement. Using immunohistochemistry assay we evaluated the RANKL (receptor activator of nuclear factor kappa B ligand) and epidermal growth factor receptor (EGFR) expression. Key findings: The EGF-liposome administration showed an increased tooth movement and osteoclast numbers compared to controls (p<0.05). This was correlated with intense RANKL expression. Both osteoblasts and osteoclasts expressed EGFR. Significance: Local delivery of EGF-liposome stimulates, osteoclastogenesis and tooth movement. (C) 2009 Elsevier Inc. All rights reserved.
Local inflammation is crucial for T cell mediated rejection of skin graft expressing foreign antigen
Resumo:
Most of the skin grafts from (K14hGH.FVB C57BL/6) F1 mice, which express foreign antigen (human growth hormone, hGH) in skin keratinocytes driven by keratin 14 promoter, were spontaneously rejected by syngeneic wild type F1 recipients and hGH-specific immune responses such as antibody and hGHspecific T cells were generated in these recipients. Interestingly, a 2nd F1 hGH-expressing skin graft was rejected by graft primed recipients, but was not rejected from such recipients if CD4+ or CD8+ T cells were depleted prior to the placement of the 2nd graft. Surprisingly, this 2nd graft retained healthy even after CD4+ or CD8+ T cells were allowed to recover so that the animal could reject a freshly placed 3rd F1 hGH-expressing graft. Furthermore, inflammatory response induced by topical treatment with imiquimod could lead to the rejection of some well-healed 2nd grafts. This result indicates that both CD4+ and CD8+ T cells are required for the rejection and the ability of effector T cells to reject a graft is determined by local factors in the graft which are presumably determined by inflammation induced by surgery or imiquimod treatment. Taken together, our results suggest that in addition to CD4+ and CD8+ T cells, local environmental factors induced by inflammation are also crucial for effector T cell functions leading to graft destruction. The understanding of these local factors will lead to more effective immunotherapy for established, epithelial cancer in the future.
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Recurrence of mucosal leishmaniasis (ML) is frequent, but the causative mechanisms are unknown. Our aim was to compare cellular and cytokine patterns of lesions from ML that evolved to recurrence or cure in order to determine the risk factor associated with recurrence. Lesions were evaluated by immunohistochemistry before and after therapy, and patients were followed-up for five years. Higher levels of CD4(+) T and IFN-gamma-producing cells were detected in active lesions and decreased after therapy. Macrophages and IL-10 were markedly increased in cured patients. Conversely, CD8(+) T and NK cells were higher in relapsed than in cured cases. Notably, a decrease in these cells in addition to decreased IL-10 and IFN-gamma was also observed after therapy. These data suggest that exacerbated CD8(+) activity, in addition to a poor regulatory response, could underlie an unfavorable fate with regard to ML. These markers may be useful for predicting the prognosis of ML in lesion studies. (C) 2008 Elsevier Inc. All rights reserved.
Resumo:
This paper examines upper-body movement kinematics in individuals with high-functioning autism (HFA) and Asperger's disorder (AD). In general, the results indicate that HFA is more consistently associated with impaired motoric preparation/initiation than AD. The data further suggest that this quantitative difference in motor impairment is not necessarily underpinned by greater executive dysfunction vulnerability in autism relative to AD. Quantitative motoric dissociation between autism and AD may have down-stream effects on later stages of movement resulting in qualitative differences between these disorder groups, e.g. motor clumsiness in AD versus abnormal posturing in autism. It will be important for future research to map the developmental trajectory of motor abnormalities in these disorder groups.
Resumo:
Eyebrow positions differ in many ways. They vary in shape, thickness, length, and distance between the eyebrows, making the face more or less harmonious. When a large distance exists between the eyebrows and the medial brow is slanting downward, the glabellar area is larger, giving the face an awkward appearance. To correct this deformity, the authors propose using two Z-plasties to allow transposition of flaps in the region of the medial brow. The Z-shaped flap is outlined at the medial third of the brow, in the glabellar region, with the eyebrow centered in the lower portion of the ""Z"" and the hairless skin in the upper portion. The flaps then are transposed and sutured. Transposition of the flaps, lifting the brow flap to the glabellar region, results in horizontal positioning of the medial and central third of the eyebrow. The proposed transpositioning of ""Z"" flaps in this region corrects this type of deformity of the medial and central portions of the eyebrows, with an aesthetically satisfactory result.
Resumo:
Reconstruction of the nipple-areola complex (NAC) is the last stage of breast reconstruction and represents the search for symmetry in regard to the contralateral breast. The objective of this study was to present an areola reconstruction technique with local skin graft to improve the texture and aspect of the reconstructed areola, searching for a natural look. This technique was performed on 122 patients who in the period from January 2000 to December 2005 were submitted to nipple and areola reconstruction. Once the position of the new nipple was determined, markings were made for the reconstruction of the areola. Then the external limit of the new areola was incised and the skin was centripetally deepidermized up to 85% of its diameter. After this procedure the detached skin was repositioned in its bed as a graft and sutured with 4.0 mononylon thread. Incisions with an 11-blade scalpel were then made in V and C forms associated with the detachment of this skin of the receptor area along the local graft so that at the end of the healing process they would determine alterations in the areolar texture mimicking the texture of a normal areola. All patients underwent tattooing 3 months after reconstruction of the NAC taking into account the different shades of the contralateral areola and nipple colors. The use of a local skin graft associated with C and V incisions allowed alteration in the texture of the reconstructed areola. The use of different ink shades for tattooing helped to give a tridimensional aspect to this areola. These factors determined a good aesthetic result in these patients. This areola reconstruction using a local skin graft allows change in the areola texture and a tridimensional aspect similar to that of a normal areola without the inconvenience of grafting from a distance.
Resumo:
This study aimed to quantify the efficiency and smoothness of voluntary movement in Huntington's disease (HD) by the use of a graphics tablet that permits analysis of movement profiles. In particular, we aimed to ascertain whether a concurrent task (digit span) would affect the kinematics of goal-directed movements. Twelve patients with HD and their matched controls performed 12 vertical zig-zag movements, with both left and right hands (with and without the concurrent task), to large or small circular targets over long or short extents. The concurrent task was associated with shorter movement times and reduced right-hand superiority. Patients with HD were overall slower, especially with long strokes, and had similar peak velocities for both small and large targets, so that controls could better accommodate differences in target size. Patients with HD spent more time decelerating, especially with small targets, whereas controls allocated more nearly equal proportions of time to the acceleration and deceleration phases of movement, especially with large targets. Short strokes were generally less force inefficient than were long strokes, especially so for either hand in either group in the absence of the concurrent task, and for the right hand in its presence. With the concurrent task, however, the left hand's behavior changed differentially for the two groups; for patients with HD, it became more force efficient with short strokes and even less efficient with long strokes, whereas for controls, it became more efficient with long strokes. Controls may be able to divert attention away from the inferior left hand, increasing its automaticity, whereas patients with HD, because of disease, may be forced to engage even further online visual control under the demands of a concurrent task. Patients with HD may perhaps become increasingly reliant on terminal visual guidance, which indicates an impairment in constructing and refining an internal representation of the movement necessary for its. effective execution. Basal ganglia dysfunction may impair the ability to use internally generated cues to guide movement.
Resumo:
Brain injury is responsible for significant morbidity and mortality in trauma patients, but controversy still exists over therapeutic management for these patients. The objective of this study was to analyze the effect of phototherapy with low intensity lasers on local and systemic immunomodulation following cryogenic brain injury. Laser phototherapy was applied (or not-controls) immediately after cryogenic brain injury performed in 51 adult male Wistar rats. The animals were irradiated twice (3 h interval), with continuous diode laser (gallium-aluminum-arsenide (GaAlAs), 780 nm, or indium-gallium-aluminum-phosphide (InGaAlP), 660 nm) in two points and contact mode, 40 mW, spot size 0.042 cm(2), 3 J/cm(2) and 5 J/cm(2) (3 s and 5 s, respectively). The experimental groups were: Control (non-irradiated), RL3 (visible red laser/ 3 J/cm(2)), RL5 (visible red laser/5 J/cm(2)), IRL3 (infrared laser/ 3 J/cm(2)), IRL5 (infrared laser/5 J/cm(2)). The production of interleukin-1IL-1 beta (IL-1 beta), interleukin6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-alpha (TNF-alpha) was analyzed by enzyme immunoassay technique (ELISA) test in brain and blood samples. The IL-1 beta concentration in brain of the control group ;was significantly reduced in 24 h (p < 0.01). This reduction was also observed in the RL5 and IRL3 groups. The TNF-alpha and IL-6 concentrations increased significantly (p < 0.01 and p < 0.05, respectively) in the blood of all groups, except by the IRL3 group. The IL-6 levels in RL3 group were significantly smaller than in control group in both experimental times. IL-10 concentration was maintained stable in all groups in brain and blood. Under the conditions of this study, it is possible to conclude that the laser phototherapy can affect TNF-alpha, IL-1 beta and IL-6 levels in the brain and in circulation in the first 24 h following cryogenic brain injury. (C) 2009 Elsevier B.V. All rights reserved.