933 resultados para edge pumping


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Today, information technology is strategically important to the goals and aspirations of the business enterprises, government and high-level education institutions – university. Universities are facing new challenges with the emerging global economy characterized by the importance of providing faster communication services and improving the productivity and effectiveness of individuals. New challenges such as provides an information network that supports the demands and diversification of university issues. A new network architecture, which is a set of design principles for build a network, is one of the pillar bases. It is the cornerstone that enables the university’s faculty, researchers, students, administrators, and staff to discover, learn, reach out, and serve society. This thesis focuses on the network architecture definitions and fundamental components. Three most important characteristics of high-quality architecture are that: it’s open network architecture; it’s service-oriented characteristics and is an IP network based on packets. There are four important components in the architecture, which are: Services and Network Management, Network Control, Core Switching and Edge Access. The theoretical contribution of this study is a reference model Architecture of University Campus Network that can be followed or adapted to build a robust yet flexible network that respond next generation requirements. The results found are relevant to provide an important complete reference guide to the process of building campus network which nowadays play a very important role. Respectively, the research gives university networks a structured modular model that is reliable, robust and can easily grow.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

OBJECTIVE: To determine the means and the reference intervals of the quantitative morphometric parameters of femoroacetabular impingement (FAI) in normal hips with high-resolution computed tomography (CT). METHODS: We prospectively included 94 adult individuals who underwent CT for thoracic, abdominal or urologic pathologies. Patients with a clinical history of hip pathology and/or with osteoarthritis on CT were excluded. We calculated means and 95 % reference intervals for imaging signs of cam-type (alpha angle at 90° and 45° and femoral head-neck offset) and pincer-type impingement (acetabular version angle, lateral centre-edge angle and acetabular index). RESULTS: The 95 % reference interval limits were all far beyond the abnormal thresholds found in the literature for cam-type and to a lesser extent for pincer-type FAI. The upper limits of the reference intervals for the alpha angles (at 90°/45°) were 68°/83° (men) and 69°/84° (women), compared to thresholds from the literature (50°, 55° or 60°). Reference intervals were similar between genders for cam-type parameters, and slightly differed for pincer-type. CONCLUSION: The 95 % reference intervals of morphometric measurements of FAI in asymptomatic hips were beyond the abnormal thresholds, which was especially true for cam-type FAI. Our results suggest the need for redefining the current morphometric parameters used in the diagnosis of FAI. KEY POINTS: ? 95 % reference intervals limits of FAI morphotype were beyond currently defined thresholds. ? Reference intervals of pincer-type morphotype measurements were close to current definitions. ? Reference intervals of cam-type morphotype measurements were far beyond the current definitions. ? Current morphometric definitions of cam-type morphotype should be used with care.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Introduction: To investigate differences in twitch and M-wave potentiation in the quadriceps femoris when electrical stimulation is applied over the quadriceps muscle belly versus the femoral nerve trunk. Methods: M-waves and mechanical twitches were evoked using direct quadriceps muscle and femoral nerve stimulation between 48 successive isometric maximal voluntary contractions (MVC) from 10 young, healthy subjects. Potentiation was investigated by analyzing the changes in M-wave amplitude recorded from the vastus medialis (VM) and vastus lateralis (VL) muscles and in quadriceps peak twitch force. Results: Potentiation of twitch, VM M-wave, and VL M-wave were greater for femoral nerve than for direct quadriceps stimulation (P<0.05). Despite a 50% decrease in MVC force, the amplitude of the M-waves increased significantly during exercise. Conclusions: In addition to enhanced electrogenic Na(+) -K(+) pumping, other factors (such as synchronization in activation of muscle fibers and muscle architectural properties) might significantly influence the magnitude of M-wave enlargement. © 2013 Wiley Periodicals, Inc.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this study, performed in a remnant of Brazilian Atlantic Forest, three types of dung from animals with distinct alimentary habits were utilized, in order to verify possible differences of attractivity of these dungs to the Scarabaeinae and the influence of seasonality in the attractivity. Three habitats were sampled: edge, clearing and forest core, each with 40 pitfall traps. A total of 2,137 beetles were collected from August 2005 to July 2006. Canthidium sp. 1 (43%) and Dichotomius sericeus (41%) were the most abundant species. From the total number of beetles collected, 80.5% were attracted to human dung, 11% to jaguar dung, 7.8% to waterbuck dung and 0.7% to the control. The species Canthidium sp.1, Canthidium sp. 2, Ateuchus sp., Canthon nigripenne, Canthonella sp. and D. sericeus came to all three bait types. Eight species were found in the baits with human dung, where Canthidium sp.1 (49%) and D. sericeus (39%) were the most common. A significant difference in attractiveness of the different baits was observed; the highest abundance found in traps baited with human dung (F = 36.59; g.l. = 3; p < 0.0001). A significant difference in richness was observed between rainy and dry seasons (F = 12.29; g.l. = 1; p < 0.001), the highest richness found in the dry season.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Abstract Accurate characterization of the spatial distribution of hydrological properties in heterogeneous aquifers at a range of scales is a key prerequisite for reliable modeling of subsurface contaminant transport, and is essential for designing effective and cost-efficient groundwater management and remediation strategies. To this end, high-resolution geophysical methods have shown significant potential to bridge a critical gap in subsurface resolution and coverage between traditional hydrological measurement techniques such as borehole log/core analyses and tracer or pumping tests. An important and still largely unresolved issue, however, is how to best quantitatively integrate geophysical data into a characterization study in order to estimate the spatial distribution of one or more pertinent hydrological parameters, thus improving hydrological predictions. Recognizing the importance of this issue, the aim of the research presented in this thesis was to first develop a strategy for the assimilation of several types of hydrogeophysical data having varying degrees of resolution, subsurface coverage, and sensitivity to the hydrologic parameter of interest. In this regard a novel simulated annealing (SA)-based conditional simulation approach was developed and then tested in its ability to generate realizations of porosity given crosshole ground-penetrating radar (GPR) and neutron porosity log data. This was done successfully for both synthetic and field data sets. A subsequent issue that needed to be addressed involved assessing the potential benefits and implications of the resulting porosity realizations in terms of groundwater flow and contaminant transport. This was investigated synthetically assuming first that the relationship between porosity and hydraulic conductivity was well-defined. Then, the relationship was itself investigated in the context of a calibration procedure using hypothetical tracer test data. Essentially, the relationship best predicting the observed tracer test measurements was determined given the geophysically derived porosity structure. Both of these investigations showed that the SA-based approach, in general, allows much more reliable hydrological predictions than other more elementary techniques considered. Further, the developed calibration procedure was seen to be very effective, even at the scale of tomographic resolution, for predictions of transport. This also held true at locations within the aquifer where only geophysical data were available. This is significant because the acquisition of hydrological tracer test measurements is clearly more complicated and expensive than the acquisition of geophysical measurements. Although the above methodologies were tested using porosity logs and GPR data, the findings are expected to remain valid for a large number of pertinent combinations of geophysical and borehole log data of comparable resolution and sensitivity to the hydrological target parameter. Moreover, the obtained results allow us to have confidence for future developments in integration methodologies for geophysical and hydrological data to improve the 3-D estimation of hydrological properties.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cape Verde is considered part of Sahelian Africa, where drought and desertification are common occurrences. The main activity of the rural population is rain-fed agriculture, which over time has been increasingly challenged by high temporal and spatial rainfall variability, lack of inputs, limited land area, fragmentation of land, steep slopes, pests, lack of mechanization and loss of top soil by water erosion. Human activities, largely through poor farming practices and deforestation (Gomez, 1989) have accelerated natural erosion processes, shifting the balance between soil erosion and soil formation (Norton, 1987). According to previous studies, vegetation cover is one of the most important factors in controlling soil loss (Cyr et al., 1995; Hupy, 2004; Zhang et al., 2004; Zhou et al., 2006). For this reason, reforestation is a touchstone of the Cape Verdean policy to combat desertification. After Independence in 1975, the Cape Verde government had pressing and closely entangled environmental and socio-economic issues to address, as long-term desertification had resulted in a lack of soil cover, severe soil erosion and a scarcity of water resources and fuel wood. Across the archipelago, desertification was resulting from a variety of processes including poor farming practices, soil erosion by water and wind, soil and water salinity in coastal areas due to over pumping and seawater intrusion, drought and unplanned urbanization (DGA-MAAP, 2004). All these issues directly affected socio-economic vulnerability in rural areas, where about 70% of people depended directly or indirectly on agriculture in 1975. By becoming part of the Inter- State Committee for the Fight against Drought in the Sahel in 1975, the government of Cape Verde gained structured support to address these issues more efficiently. Presentday policies and strategies were defined on the basis of rational use of resources and human efforts and were incorporated into three subsequent national plans: the National Action Plan for Development (NDP) (1982–1986), the NDP (1986–1990) and the NDP (1991–1995) (Carvalho

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Aortic access problems due to diseased or small peripheral vessels are a major issue in endovascular aneurysm repair (EVAR). In the emergency setting, like aortic rupture after blunt trauma, or in patients with a hostile abdomen, a more proximal access to the aorta is not a pleasant perspective. We developed in situ introducer sheath dilatation as a bail-out technique for patients with difficult aortic access under various circumstances including EVAR, intra-aortic balloon pump insertion and cannulation for perfusion. The method described allows to increase the access vessel diameter by 50% (from 6 to 9 mm) or the luminal circumference from 18 to 27 F. We have used this technique in five patients without complication, very much in contrast to the traditionally practiced 'forced device insertion'.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The pattern of genetic variation of the lizard Mabuya maculilabris from São Tomé Island (Gulf of Guinea) was investigated using a combination of three mitochondrial DNA gene fragments. Forty-eight haplotypes were recovered among 66 individuals covering the whole island. The genealogy inferred from the most parsimonious network of haplotypes allows us to detect two main and long branches departing from the putative group of oldest haplotypes. The tips of these branches exhibit star-like phylogenies, which may indicate of recently expanded populations, most probably from a small number of founders. A nested clade analysis suggests a complex pattern of past events that gave rise to the extant geographical pattern found in the haplotype distribution: past and allopatric fragmentation, range expansion, restricted gene Xow and long-distance dispersal. These results are consistent with the complex geological history of the island where important volcanic activity with extensive lava Xows has occurred during several periods. Mismatch- distribution analysis and AMOVA also support these conclusions. Substantial genetic structuring among these lizards was detected as well as high levels of diVerentiation between the southern edge populations (particularly those from the Rolas Islet) and the remaining ones. However, variation is low relative to the geological age of the island. Our results indicate that patterns of variation observed in reptiles in other oceanic islands are not indicative of those observed in the islands of the Gulf of Guinea.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Fauna of phlebotomine sand flies (Diptera, Psychodidae) in areas with endemic American cutaneous leishmaniasis in the State of Mato Grosso do Sul, Brazil. The aim of this study was to investigate the ecological aspects of the main vectors of American cutaneous leishmaniasis (ACL) in four monitoring stations situated in the municipalities of Naviraí, Nova Andradina, Novo Horizonte do Sul and Rio Verde de Mato Grosso. For each monitoring station, the captures of sand flies were undertaken each month from July 2008 to June 2010 using CDC and Shannon traps. The CDC traps were installed simultaneously for three consecutive nights in three collection sites: intradomicile, peridomicile and edge of the forest. A Shannon trap was installed from dusk to 10 pm, inside the forest, one night per month. A total of 7,651 sand flies belonging to nine genera and twenty-nine species were captured. Nyssomyia neivai (52.95%), Psathyromyia hermanlenti (10.91%), Psathyromyia runoides (9.16%), Nyssomyia whitmani (7.95%), Psathyromyia aragaoi (4. 89%), Nyssomyia antunesi (3.14%) and Evandromyia bourrouli (2.20%) were the most frequent species. Approximately 65% of the sand flies were collected in the forest environment. The municipalities presented significantly different indexes of species diversity. Naviraí presented the lowest species diversity index, however, it showed the highest abundance. Novo Horizonte do Sul had the highest species diversity index, but the lowest abundance (< 5%). It is noteworthy the occurrence of vector species of Leishmania in the areas studied, especially in Naviraí, where Ny. neivai presented high frequencies which may explain the increased number of ACL cases in this municipality.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Summary: Capitalizing on the forest : use, users and change in the forest in the wilderness economy on the edge of the taiga in Eastern Finland through the year 2000

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Para determinar la variabilidad estacional y espacial en el fondo marino del norte peruano, durante los últimos 30 años (1980-2009), se estudió la temperatura y el oxígeno disuelto entre las latitudes 3°-7°S. Se halló una mayor proyección latitudinal del oxígeno disuelto (OD), superior a 1,0 mL/L en la estación de otoño, delimitada por la isoterma de 15 °C al borde de la plataforma. Esta proyección estaría asociada a los flujos subsuperficiales hacia el sur, que constituyen la Extensión Sur de la Corriente de Cromwell (ESCC), a profundidades de 90-180 m. La oxigenación estaría influenciada por el incremento o repliegue de la ESCC presente en el área. La variación media de oxígeno registra valores de 0,7-1,3 mL/L en verano y 0,8-1,6 mL/L en otoño. Paita (5°S) presenta valores promedio de 1,0 mL/L en verano y de 1,4 mL/L en otoño. Los mayores valores de OD se asocian a latitudes menores en ambas estaciones; la estación de otoño presenta los mayores tenores de oxígeno, asociados a una mayor intensidad de la ESCC.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El objetivo de este trabajo es estudiar las variaciones ontogénicas, espaciales y nictemerales en la dieta de la anchoveta peruana (Engraulis ringens). El trabajo se basa en el análisis de contenido estomacal de 13 430 anchovetas (peces de 4 a 19,5 cm) muestreados durante 22 cruceros de investigación realizados a bordo de las embarcaciones científicas del Instituto del Mar del Perú durante el período 1996-2003. Previo a los análisis estadísticos la contribución de cada grupo de presa fue convertido a carbonó. Los datos fueron procesados por medio de estadística uni y multivariada en función de la talla de la anchoveta, la latitud, la distancia de la costa, la distancia del borde de la plataforma continental y el período nictemeral. Los resultados enseñan que la anchoveta se alimenta mayormente de zooplancton cualquier sea su tamaño o su distribución espaciotemporal. La anchoveta cambio gradualmente su dieta a lo largo de su ciclo de vida. Así, los individuos mas pequeños han ingerido mayormente copépodos calanoideos (68.0%) y eufausidos (23.3%), mientras que los individuos mas grandes ingirieron mayormente eufausidos (84.9%) y copépodos calanoideos (11.5%). Latitudinalmente, la mayor contribución de los copépodos calanoideos se observó en las zonas de afloramiento de Chicama y San Juan, con el 52.3% y 47.5%, respectivamente. Hasta los 160 km de distancia de la costa, no se ha observado un patrón regular en la contribución de las principales presas, mientras que por fuera, se insinúa un patrón caracterizado por el predominio de los eufausidos (>84%) y la menor contribución de copépodos calanoideos (<14,1%). En la plataforma continental los eufausidos contribuyeron con el 55.6% y los copépodos calanoideos con el 36.9%; mientras que por fuera de esa zona, los eufausidos se incrementaron al 75.3% y los copépodos calanoideos disminuyeron al 20.1%. Al considerar el período nictemeral, el ítem presa predominante durante el día fueron los eufausidos (52.7%) seguido de los copépodos calanoideos (40.9%); mientras que durante la noche, los eufausidos se incrementaron al 80.2% y los copépodos calanoideos disminuyeron al 15.7%. Estos resultados contradicen lo que se conocía acerca de la variabilidad de la dieta de la anchoveta, desestimándose: (i) que en el norte es fitoplanctívora y en el sur es zooplanctívora; (ii) que la fracción zooplanctónica es mayor en la zona oceánica. Asimismo, se ha demostrado que: (i) la anchoveta es principalmente zooplanctófaga durante su ciclo de vida, con modificaciones que corresponden a la mayor ingesta de presas pequeñas cuando son juveniles y de presas grandes cuando son adultas, (ii) en la zona de influencia de la plataforma continental consume aproximadamente el doble de copépodos calanoideos que en la zona oceánica, y aproximadamente una tercera parte menos de eufausidos en la zona interna que en la zona oceánica, y (iii) durante la noche y el día ingiere principalmente eufausidos pero la contribución de los copépodos calanoideos sube al 40%.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

BACKGROUND: Three-dimensional (3D) navigator-gated and prospectively corrected free-breathing coronary magnetic resonance angiography (MRA) allows for submillimeter image resolution but suffers from poor contrast between coronary blood and myocardium. Data collected over >100 ms/heart beat are also susceptible to bulk cardiac and respiratory motion. To address these problems, we examined the effect of a T2 preparation prepulse (T2prep) for myocardial suppression and a shortened acquisition window on coronary definition. METHODS AND RESULTS: Eight healthy adult subjects and 5 patients with confirmed coronary artery disease (CAD) underwent free-breathing 3D MRA with and without T2prep and with 120- and 60-ms data-acquisition windows. The T2prep resulted in a 123% (P<0. 001) increase in contrast-to-noise ratio (CNR). Coronary edge definition was improved by 33% (P<0.001). Acquisition window shortening from 120 to 60 ms resulted in better vessel definition (11%; P<0.001). Among patients with CAD, there was a good correspondence with disease. CONCLUSIONS: Free-breathing, T2prep, 3D coronary MRA with a shorter acquisition window resulted in improved CNR and better coronary artery definition, allowing the assessment of coronary disease. This approach offers the potential for free-breathing, noninvasive assessment of the major coronary arteries.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The pool of mature T cells comprises a heterogeneous mixture of naive and memory CD4(+) and CD8(+) cells. These cells are long lived at a population level but differ markedly in their relative rates of turnover and survival. Here, we review how contact with exogenous stimuli, notably self MHC ligands and various gamma(c) cytokines, plays a decisive role in controlling normal T cell homeostasis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Investigations of solute transport in fractured rock aquifers often rely on tracer test data acquired at a limited number of observation points. Such data do not, by themselves, allow detailed assessments of the spreading of the injected tracer plume. To better understand the transport behavior in a granitic aquifer, we combine tracer test data with single-hole ground-penetrating radar (GPR) reflection monitoring data. Five successful tracer tests were performed under various experimental conditions between two boreholes 6 m apart. For each experiment, saline tracer was injected into a previously identified packed-off transmissive fracture while repeatedly acquiring single-hole GPR reflection profiles together with electrical conductivity logs in the pumping borehole. By analyzing depth-migrated GPR difference images together with tracer breakthrough curves and associated simplified flow and transport modeling, we estimate (1) the number, the connectivity, and the geometry of fractures that contribute to tracer transport, (2) the velocity and the mass of tracer that was carried along each flow path, and (3) the effective transport parameters of the identified flow paths. We find a qualitative agreement when comparing the time evolution of GPR reflectivity strengths at strategic locations in the formation with those arising from simulated transport. The discrepancies are on the same order as those between observed and simulated breakthrough curves at the outflow locations. The rather subtle and repeatable GPR signals provide useful and complementary information to tracer test data acquired at the outflow locations and may help us to characterize transport phenomena in fractured rock aquifers.