948 resultados para Wall Street.
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Two types of welfare states are compared in this article. Differences in procedural rights for young unemployed at the level of service delivery are analyzed. In Australia, rights are regulated through a rigid procedural justice system. The young unemployed within the social assistance system in Sweden encounter staff with high discretionary powers, which makes the legal status weak for the unemployed but, on the other hand, the system is more flexible. Despite the differences, there is striking convergence in how the young unemployed describe how discretionary power among street-level staff affects their procedural rights. This result can be understood as a result of similar professional norms, work customs and occupational cultures of street-level staff, and that there is a basic logic of conditionality in all developed welfare states where procedural rights are tightly coupled with responsibilities.
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Measurements of particle concentrations and distributions in terms of number, surface area, and mass were performed simultaneously at eight sampling points within a symmetric street canyon of an Italian city. The aim was to obtain a useful benchmark for validation of wind tunnel experiments and numerical schemes: to this purpose, the influence of wind directions and speeds was considered. Particle number concentrations (PNCs) were higher on the leeward side than the windward side of the street canyon due to the wind vortex effect. Different vertical PNC profiles were observed between the two canyon sides depending on the wind direction and speed at roof level. A decrease in particle concentrations was observed with increasing rooftop wind speed, except for the coarse fraction indicating a possible particle resuspension due to the traffic and wind motion. This study confirms that particle concentration fields in urban street canyons are strongly influenced by traffic emissions and meteorological parameters, especially wind direction and speed.
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HIV risk in vulnerable groups such as itinerant male street labourers is often examined via a focus on individual determinants. This study provides a test of a modified Information-Motivation-Behavioral Skills (IMB) model to predict condom use behaviour among male street workers in urban Vietnam. In a cross-sectional survey using a social mapping technique, 450 male street labourers from 13 districts of Hanoi, Vietnam were recruited and interviewed. Collected data were first examined for completeness; structural equation modelling was then employed to test the model fit. Condoms were used inconsistently by many of these men, and usage varied in relation to a number of factors. A modified IMB model had a better fit than the original IMB model in predicting condom use behaviour. This modified model accounted for 49% of the variance, versus 10% by the original version. In the modified model, the influence of psychosocial factors was moderately high, whilst the influence of HIV prevention information, motivation and perceived behavioural skills was moderately low, explaining in part the limited level of condom use behaviour. This study provides insights into social factors that should be taken into account in public health planning to promote safer sexual behaviour among Asian male street labourers.
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Embracing the pleasures of constraint, this new house by James Russell Architect was designed to contextually inspired principles, creating a social and relaxed environment that suits the location’s subtropical way of life.
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Unsteady natural convection flow in a two- dimensional square cavity filled with a porous material has been studied. The flow is initially steady where the left- hand vertical wall has temperature T-h and the right- hand vertical wall is maintained at temperature T-c ( T-h > T-c) and the horizontal walls are insulated. At time t > 0, the left- hand vertical wall temperature is suddenly raised to (T-h) over bar ((T-h) over bar > T-h) which introduces unsteadiness in the flow field. The partial differential equations governing the unsteady natural convection flow have been solved numerically using a finite control volume method. The computation has been carried out until the final steady state is reached. It is found that the average Nusselt number attains a minimum during the transient period and that the time required to reach the final steady state is longer for low Rayleigh number and shorter for high Rayleigh number.
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Background: Inflammation and biomechanical factors have been associated with the development of vulnerable atherosclerotic plaques. Lipid-lowering therapy has been shown to be effective in stabilizing them by reducing plaque inflammation. Its effect on arterial wall strain, however, remains unknown. The aim of the present study was to investigate the role of high- and low-dose lipid-lowering therapy using an HMG-CoA reductase inhibitor, atorvastatin, on arterial wall strain. Methods and Results: Forty patients with carotid stenosis >40% were successfully followed up during the Atorvastatin Therapy: Effects on Reduction Of Macrophage Activity (ATHEROMA; ISRCTN64894118) Trial. All patients had plaque inflammation as shown by intraplaque accumulation of ultrasmall super paramagnetic particles of iron oxide on magnetic resonance imaging at baseline. Structural analysis was performed and change of strain was compared between high- and low-dose statin at 0 and 12 weeks. There was no significant difference in strain between the 2 groups at baseline (P=0.6). At 12 weeks, the maximum strain was significantly lower in the 80-mg group than in the 10-mg group (0.085±0.033 vs. 0.169±0.084; P=0.001). A significant reduction (26%) of maximum strain was observed in the 80-mg group at 12 weeks (0.018±0.02; P=0.01). Conclusions: Aggressive lipid-lowering therapy is associated with a significant reduction in arterial wall strain. The reduction in biomechanical strain may be associated with reductions in plaque inflammatory burden.
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In this paper, we present a new approach for velocity vector imaging and time-resolved measurements of strain rates in the wall of human arteries using MRI and we prove its feasibility on two examples: in vitro on a phantom and in vivo on the carotid artery of a human subject. Results point out the promising potential of this approach for investigating the mechanics of arterial tissues in vivo.
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Background: Biomechanical stresses play an important role in determining plaque stability. Quantification of these simulated stresses can be potentially used to assess plaque vulnerability and differentiate different patient groups. Methods and Results: 54 asymptomatic and 45 acutely symptomatic patients underwent in vivo multicontrast magnetic resonance imaging (MRI) of the carotid arteries. Plaque geometry used for finite element analysis was derived from in vivo MRI at the sites of maximum and minimum plaque burden. In total, 198 slices were used for the computational simulations. A pre-shrink technique was used to refine the simulation. Maximum principle stress at the vulnerable plaque sites (ie, critical stress) was extracted for the selected slices and a comparison was performed between the 2 groups. Critical stress in the slice with maximum plaque burden is significantly higher in acutely symptomatic patients as compared to asymptomatic patients (median, inter quartile range: 198.0 kPa (119.8-359.0 kPa) vs 138.4 kPa (83.8-242.6 kPa), P=0.04). No significant difference was found in the slice with minimum plaque burden between the 2 groups (196.7 kPa (133.3-282.7 kPa) vs 182.4 kPa (117.2-310.6 kPa), P=0.82). Conclusions: Acutely symptomatic carotid plaques have significantly high biomechanical stresses than asymptomatic plaques. This might be potentially useful for establishing a biomechanical risk stratification criteria based on plaque burden in future studies.
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Growth rate of abdominal aortic aneurysm (AAA) is thought to be an important indicator of the potential risk of rupture. Wall stress is also thought to be a trigger for its rupture. However, stress change during the expansion of an AAA is unclear. Forty-four patients with AAAs were included in this longitudinal follow-up study. They were assessed by serial abdominal ultrasonography and computerized tomography (CT) scans if a critical size was reached or a rapid expansion occurred. Patient-specific 3-dimensional AAA geometries were reconstructed from the follow-up CT images. Structural analysis was performed to calculate the wall stresses of the AAA models at both baseline and final visit. A non-linear large-strain finite element method was used to compute the wall stress distribution. The average growth rate was 0.66cm/year (range 0-1.32 cm/year). A significantly positive correlation between shoulder tress at baseline and growth rate was found (r=0.342; p=0.02). A higher shoulder stress is associated with a rapidly expanding AAA. Therefore, it may be useful for estimating the growth expansion of AAAs and further risk stratification of patients with AAAs.
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Background: Increased biomechanical stresses within the abdominal aortic aneurysm (AAA) wall contribute to its rupture. Calcification and intraluminal thrombus can be commonly found in AAAs, but the relationship between calcification/intraluminal thrombus and AAA wall stress is not completely described. Methods: Patient-specific three-dimensional AAA geometries were reconstructed from computed tomographic images of 20 patients. Structural analysis was performed to calculate the wall stresses of the 20 AAA models and their altered models when calcification or intraluminal thrombus was not considered. A nonlinear large-strain finite element method was used to compute the wall stress distribution. The relationships between wall stresses and volumes of calcification and intraluminal thrombus were sought. Results: Maximum stress was not correlated with the percentage of calcification, and was negatively correlated with the percentage of intraluminal thrombus (r = -0.56; P = .011). Exclusion of calcification from analysis led to a significant decrease in maximum stress by a median of 14% (range, 2%-27%; P < .01). When intraluminal thrombus was eliminated, maximum stress increased significantly by a median of 24% (range, 5%-43%; P < .01). Conclusion: The presence of calcification increases AAA peak wall stress, suggesting that calcification decrease the biomechanical stability of AAA. In contrast, intraluminal thrombus reduces the maximum stress in AAA. Calcification and intraluminal thrombus should both be considered in the evaluation of wall stress for risk assessment of AAA rupture.
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Rupture of vulnerable atheromatous plaque in the carotid and coronary arteries often leads to stroke and heart attack respectively. The mechanism of blood flow and plaque rupture in stenotic arteries is still not fully understood. A three dimensional rigid wall model was solved under steady state conditions and unsteady conditions by assuming a time-varying inlet velocity profile to investigate the relative importance of axial forces and pressure drops in arteries with asymmetric stenosis. Flow-structure interactions were investigated for the same geometry and the results were compared with those retrieved with the corresponding 2D cross-section structural models. The Navier-Stokes equations were used as the governing equations for the fluid. The tube wall was assumed hyperelastic, homogeneous, isotropic and incompressible. The analysis showed that the three dimensional behavior of velocity, pressure and wall shear stress is in general very different from that predicted by cross-section models. Pressure drop across the stenosis was found to be much higher than shear stress. Therefore, pressure may be the more important mechanical trigger for plaque rupture other than shear stress, although shear stress is closely related to plaque formation and progression.
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An analysis has been carried out to study the non-Darcy natural convention flow of Newtonian fluids on a vertical cone embedded in a saturated porous medium with power-law variation of the wall temperature/concentration or heat/mass flux and suction/injection with the streamwise distance x. Both non-similar and self-similar solutions have been obtained. The effects of non-Darcy parameter, ratio of the buoyancy forces due to mass and heat diffusion, variation of wall temperature/concentration or heat/mass flux and suction/injection on the Nusselt and Sherwood numbers have been studied.
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Tutkielmani käsittelee yhdysvaltalaisen kirjailijan Paul Austerin (s. 1947) romaanituotannossa esiintyviä esteitä ja rajatiloja. Erityisesti olen kiinnostunut siitä, miten Auster liittää nämä "marginaalitilat" amerikkalaiseen vapauden ja laajentumisen ideologiaan sekä kieleen ja kirjoittamiseen. Austerin romaaneissa esteiden ja rajatilojen käsittely voidaan jakaa kolmeen vaiheeseen. Ensimmäisessä vaiheessa henkilöt ovat vahvojen esteiden rajoittamia tai rakentavat niitä itse. Rajoittuneisuus ei kuitenkaan aina tunnu häiritsevän heitä - itse asiassa monet päähenkilöistä tuntevat itsensä onnellisiksi tai vähintäänkin tyytyväisiksi joutuessaan esteen takia pysähdyttämään vapaan liikkeensä. Toisessa vaiheessa henkilöt pyrkivät ylittämään tai rikkomaan esteen päästäkseen toiselle puolelle. Kuten amerikkalaiset esi-isänsä aikoinaan, he etsivät rajatonta, laajaa ja tyhjää tilaa - "suurta tuntematonta" valloitettavakseen. Tällaisen tilan kohdatessaan he joutuvat kuitenkin usein epävarmuuden valtaan. Kolmas vaihe on tutkielmani kannalta tärkein: välitila, josta käytän työssäni nimitystä "in-betweenity". Tähän vaiheeseen päästään kulkemalla ensin kahden muun vaiheen kautta. Juuri tietoisuus näistä kahdesta muusta vaiheesta synnyttää tämän kolmannen tilan, eräänlaisen rajatilan, jossa tajutaan sekä esteiden että esteettömyyden tärkeys. Tämä välitila on Austerille tyypillinen tila, joka kertoo paitsi amerikkalaisen unelman paradoksaalisuudesta myös (kaunokirjallisen) kielenkäytön prosessista. Monet Austerin kirjojen muurin rakentajista tai purkajista voidaan nähdä kirjailijahahmoina, joiden omituinen suhde esteisiin ja rajoihin kumpuaa juuri siitä rajatilasta, jonka asukkaita he kielentaiteilijoina väistämättä ovat. Tällaisen tilan/tilattomuuden kuvaaminen tekee Austerista oman postmodernin aikamme tärkeän kirjailijan - kirjailijan, joka sen sijaan, että pyrkisi eroon paradokseista, sijoittaa hahmonsa niiden sisään. Rajoihin ja esteisiin liittyvä problematiikka ei kuitenkaan ole pelkästään nykyajan ongelma vaan kysymys, joka ihmisen toisaalta rajoja kaipaavan toisaalta rajattomuutta kaipaavan luonteen vuoksi säilyy aina ajankohtaisena. Avainsanat: Paul Auster, este, muuri, raja, Yhdysvallat
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