966 resultados para Rao-Yu model


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Block print.

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Magdeburg, Univ., Fak. für Mathematik, Diss., 2009

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Hong Kong’s currency is pegged to the US dollar in a currency board arrangement. In autumn 2003, the Hong Kong dollar appreciated from close to 7.80 per US dollar to 7.70, as investors feared that the currency board would be abandoned. In the wake of this appreciation, the monetary authorities revamped the one-sided currency board mechanism into a symmetric two-sided system with a narrow exchange rate band. This paper reviews the characteristics of the new currency board arrangement and embeds a theoretical soft edge target zone model typifying many intermediate regimes, to explain the notable achievement of speculative peace and credibility since May 2005.

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PURPOSE: The purpose of this study was to study the pharmacokinetics of irinotecan injected intravenously, intra-arterially, or loaded onto a delivery platform. MATERIAL AND METHODS: Fifty-four New Zealand White rabbits with VX2 liver tumor, divided in 3 groups of 17 rabbits, each received irinotecan either by intravenous (IV) route, intra-arterial hepatic (IA) route, or loaded on drug-eluting beads (DEBIRI). Animals were killed at 1, 6, and 24 h. Irinotecan and SN-38 concentrations were measured at different time points in serum, tumor, and normal liver. RESULTS: Twelve milligrams of irinotecan were injected IV and IA, whereas 6-16.5 mg were injected loaded onto DEBIRI. Normalized serum irinotecan reached a peak of 333 ng/ml (range 198.8-502.5) for IV, 327.1 ng/ml (range 277.1-495.6) for IA, and 189.7 ng/ml (range 111.1-261.9) for DEBIRI (P < 0.001) delivery. The area-under-the-curve value from 10 to 60 min of serum irinotecan concentration was significantly lower for DEBIRI (P = 0.0009). Tumor irinotecan levels for IV, IA, and DEBIRI (in ng/200 mg of tissue followed by ranges in parentheses) were, respectively, 23.6 (0.3-24.9), 36.5 (7.7-1914.1), and 20.2 (2.9-319) at 1 h; 4.2 (1-27.9), 99.3 (46.6-159.5), and 42.1 (11.3-189) at 6 h; and 2.7 (2.5-6.9), 18.3 (1.5-369.1), and 174.4 (3.4-5147.3) at 24 h (P = 0.02). At 24 h, tumor necrosis was 25% (10-30), 60% (40-91.25), and 95% (76.25-95) for IV, IA, and DEBIRI, respectively (P = 0.03). CONCLUSION: Compared with IV or IA, DEBIRI induces lower early serum levels of irinotecan, a high and prolonged intratumoral level of irinotecan, and a greater rate of tumor necrosis at 24 h. Further evaluation of the clinical benefit of DEBIRI is warranted.

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Wear particles are phagocytosed by macrophages and other inflammatory cells, resulting in cellular activation and release of proinflammatory factors, which cause periprosthetic osteolysis and subsequent aseptic loosening, the most common causes of total joint arthroplasty failure. During this pathological process, tumor necrosis factor-alpha (TNF-α) plays an important role in wear-particle-induced osteolysis. In this study, recombination adenovirus (Ad) vectors carrying both target genes [TNF-α small interfering RNA (TNF-α-siRNA) and bone morphogenetic protein 2 (BMP-2)] were synthesized and transfected into RAW264.7 macrophages and pro-osteoblastic MC3T3-E1 cells, respectively. The target gene BMP-2, expressed on pro-osteoblastic MC3T3-E1 cells and silenced by the TNF-α gene on cells, was treated with titanium (Ti) particles that were assessed by real-time PCR and Western blot. We showed that recombinant adenovirus (Ad-siTNFα-BMP-2) can induce osteoblast differentiation when treated with conditioned medium (CM) containing RAW264.7 macrophages challenged with a combination of Ti particles and Ad-siTNFα-BMP-2 (Ti-ad CM) assessed by alkaline phosphatase activity. The receptor activator of nuclear factor-κB ligand was downregulated in pro-osteoblastic MC3T3-E1 cells treated with Ti-ad CM in comparison with conditioned medium of RAW264.7 macrophages challenged with Ti particles (Ti CM). We suggest that Ad-siTNFα-BMP-2 induced osteoblast differentiation and inhibited osteoclastogenesis on a cell model of a Ti particle-induced inflammatory response, which may provide a novel approach for the treatment of periprosthetic osteolysis.

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An enterovirus 71 (EV71) vaccine for the prevention of hand, foot, and mouth disease (HMFD) is available, but it is not known whether the EV71 vaccine cross-protects against Coxsackievirus (CV) infection. Furthermore, although an inactivated circulating CVA16 Changchun 024 (CC024) strain vaccine candidate is effective in newborn mice, the CC024 strain causes severe lesions in muscle and lung tissues. Therefore, an effective CV vaccine with improved pathogenic safety is needed. The aim of this study was to evaluate the in vivo safety and in vitro replication capability of a noncirculating CVA16 SHZH05 strain. The replication capacity of circulating CVA16 strains CC024, CC045, CC090 and CC163 and the noncirculating SHZH05 strain was evaluated by cytopathic effect in different cell lines. The replication capacity and pathogenicity of the CC024 and SHZH05 strains were also evaluated in a neonatal mouse model. Histopathological and viral load analyses demonstrated that the SHZH05 strain had an in vitro replication capacity comparable to the four CC strains. The CC024, but not the SHZH05 strain, became distributed in a variety of tissues and caused severe lesions and mortality in neonatal mice. The differences in replication capacity and in vivo pathogenicity of the CC024 and SHZH05 strains may result from differences in the nucleotide and amino acid sequences of viral functional polyproteins P1, P2 and P3. Our findings suggest that the noncirculating SHZH05 strain may be a safer CV vaccine candidate than the CC024 strain.

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We aimed to investigate the effects of an anti-tumor necrosis factor-α antibody (ATNF) on cartilage and subchondral bone in a rat model of osteoarthritis. Twenty-four rats were randomly divided into three groups: sham-operated group (n=8); anterior cruciate ligament transection (ACLT)+normal saline (NS) group (n=8); and ACLT+ATNF group (n=8). The rats in the ACLT+ATNF group received subcutaneous injections of ATNF (20 μg/kg) for 12 weeks, while those in the ACLT+NS group received NS at the same dose for 12 weeks. All rats were euthanized at 12 weeks after surgery and specimens from the affected knees were harvested. Hematoxylin and eosin staining, Masson's trichrome staining, and Mankin score assessment were carried out to evaluate the cartilage status and cartilage matrix degradation. Matrix metalloproteinase (MMP)-13 immunohistochemistry was performed to assess the cartilage molecular metabolism. Bone histomorphometry was used to observe the subchondral trabecular microstructure. Compared with the rats in the ACLT+NS group, histological and Mankin score analyses showed that ATNF treatment reduced the severity of the cartilage lesions and led to a lower Mankin score. Immunohistochemical and histomorphometric analyses revealed that ATNF treatment reduced the ACLT-induced destruction of the subchondral trabecular microstructure, and decreased MMP-13 expression. ATNF treatment may delay degradation of the extracellular matrix via a decrease in MMP-13 expression. ATNF treatment probably protects articular cartilage by improving the structure of the subchondral bone and reducing the degradation of the cartilage matrix.

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En Colombia, después de casi dos décadas de la creación del régimen de cuentas privadas, se implementó una reforma donde se pasa de un sistema con un unico fondo a uno multifondos. Este tipo de reformas se vienen implementando en diferentes paises europeos y de Latino America. A la luz de las teorías clásicas dicha reforma trae mejoras en el bienestar de los individuos; sin embargo, la literatura sobre las nuevas teorías del comportamiento sugiere que los individuos no siempre toman decisiones que están de acuerdo con los supuestos de las teorías clásicas. Este trabajo estudia esta reforma en Colombia bajo algunas de las teorías del comportamiento financiero. Se encuentra que aún cuando el afiliado se quede en la opción default , o actúe con aversión a la pérdida, va a obtener valores en sus cuentas privadas mayores a las que obtendría con un sistema de un único fondo.

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En Colombia, después de casi dos décadas de la creación del régimen de cuentas privadas, se implementó una reforma donde se pasa de un sistema con un único fondo a uno multifondos. Este tipo de reformas se vienen implementando en diferentes países europeos y de Latino América. A la luz de las teorías clásicas dicha reforma trae mejoras en el bienestar de los individuos; sin embargo, la literatura sobre las nuevas teorías del comportamiento sugiere que los individuos no siempre toman decisiones que están de acuerdo con los supuestos de las teorías clásicas. Este trabajo estudia esta reforma en Colombia bajo algunas de las teorías del comportamiento financiero. Se encuentra que aún cuando el afiliado se quede en la opción default , o actúe con aversión a la pérdida, va a obtener valores en sus cuentas privadas mayores a las que obtendría con un sistema de un único fondo.

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Introducción: La hipertensión arterial es un problema de salud pública tanto en países industrializados como en vía de desarrollo. Su prevalencia en la infancia viene en aumento por lo que es relevante determinarla en niños preescolares a nivel local. Objetivo: Determinar la prevalencia de hipertensión arterial en niños de tres a cinco años de una cohorte de 14 hogares infantiles del ICBF de la localidad de Usaquén en Bogotá. Materiales y métodos: Se realizó un estudio de corte transversal analítico, utilizando la base de datos de un ensayo aleatorizado y controlado del año 200913, y se evaluaron las cifras de tensión arterial de acuerdo a sexo, edad, talla y su correlación con el IMC con un nivel de confianza del 95% y precisión del 1%. Se calcularon las medias, desviaciones estándar, percentiles y prevalencia. Resultados: Se obtuvo una muestra de 1035 casos, encontrándose una prevalencia de 4,5% de HTA sistólica, 10,4% de diastólica, ambas en estadio I; teniendo en cuenta tanto sistólica como diastólica, fue de 11,6% en estadio I. Se determinaron los valores de presión arterial sistólica y diastólica en cuartiles de acuerdo a edad, sexo y talla. El coeficiente de correlación entre el IMC y los niveles de presión arterial sistólica y diastólica fueron de 0.0992 y 0.0362 respectivamente. Conclusión: La prevalencia de HTA general fue de 11,6%, predominando la diastólica en estadio I en niños preescolares. No se encontró correlación entre el IMC y las cifras de tensión arterial sistólica y diastólica.

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We analyze how the characteristics of El Niño-Southern Oscillation (ENSO) are changed in coupled ocean–atmosphere simulations of the mid-Holocene (MH) and the Last Glacial Maximum (LGM) performed as part of the Paleoclimate Modeling Intercomparison Project phase 2 (PMIP2). Comparison of the model results with present day observations show that most of the models reproduce the large scale features of the tropical Pacific like the SST gradient, the mean SST and the mean seasonal cycles. All models simulate the ENSO variability, although with different skill. Our analyses show that several relationships between El Niño amplitude and the mean state across the different control simulations are still valid for simulations of the MH and the LGM. Results for the MH show a consistent El Niño amplitude decrease. It can be related to the large scale atmospheric circulation changes. While the Northern Hemisphere receives more insolation during the summer time, the Asian summer monsoon system is strengthened which leads to the enhancement of the Walker circulation. Easterlies prevailing over the central eastern Pacific induce an equatorial upwelling that damps the El Niño development. Results are less conclusive for 21ka. Large scale dynamic competes with changes in local heat fluxes, so that model shows a wide range of responses, as it is the case in future climate projections.

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While building provides shelter for human being, the previous models for assessing the intelligence of a building seldom consider the responses of occupants. In addition, the assessment is usually conducted by an authority organization on a yearly basis, thus can seldom provide timely assistance for facility manager to improve his daily facility maintenance performance. By the extending the law of entropy into the area of intelligent building, this paper demonstrate that both energy consumption and the response of occupants are important when partially assessing the intelligence of a building. This study then develops a sensor based real time building intelligence (BI) assessment model. An experimental case study demonstrates how the model can be implemented. The developed model can address the two demerits of the previous BI assessment model.

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Leading time length is an important issue for modeling seasonal forecasts. In this study, a comparison of the interannual predictability of the Western North Pacific (WNP) summer monsoon between different leading months was performed by using one-, four-, and seven-month lead retrospective forecasts (hindcasts) of four coupled models from Ensembles-Based Predictions of Climate Changes and Their Impacts (ENSEMBLES) for the period of 1960-2005. It is found that the WNP summer anomalies, including lower-tropospheric circulation and precipitation anomalies, can be well predicted for all these leading months. The accuracy of the four-month lead prediction is only slightly weaker than that of the one-month lead prediction, although the skill decreases with the increase of leading months.

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Global wetlands are believed to be climate sensitive, and are the largest natural emitters of methane (CH4). Increased wetland CH4 emissions could act as a positive feedback to future warming. The Wetland and Wetland CH4 Inter-comparison of Models Project (WETCHIMP) investigated our present ability to simulate large-scale wetland characteristics and corresponding CH4 emissions. To ensure inter-comparability, we used a common experimental protocol driving all models with the same climate and carbon dioxide (CO2) forcing datasets. The WETCHIMP experiments were conducted for model equilibrium states as well as transient simulations covering the last century. Sensitivity experiments investigated model response to changes in selected forcing inputs (precipitation, temperature, and atmospheric CO2 concentration). Ten models participated, covering the spectrum from simple to relatively complex, including models tailored either for regional or global simulations. The models also varied in methods to calculate wetland size and location, with some models simulating wetland area prognostically, while other models relied on remotely sensed inundation datasets, or an approach intermediate between the two. Four major conclusions emerged from the project. First, the suite of models demonstrate extensive disagreement in their simulations of wetland areal extent and CH4 emissions, in both space and time. Simple metrics of wetland area, such as the latitudinal gradient, show large variability, principally between models that use inundation dataset information and those that independently determine wetland area. Agreement between the models improves for zonally summed CH4 emissions, but large variation between the models remains. For annual global CH4 emissions, the models vary by ±40% of the all-model mean (190 Tg CH4 yr−1). Second, all models show a strong positive response to increased atmospheric CO2 concentrations (857 ppm) in both CH4 emissions and wetland area. In response to increasing global temperatures (+3.4 °C globally spatially uniform), on average, the models decreased wetland area and CH4 fluxes, primarily in the tropics, but the magnitude and sign of the response varied greatly. Models were least sensitive to increased global precipitation (+3.9 % globally spatially uniform) with a consistent small positive response in CH4 fluxes and wetland area. Results from the 20th century transient simulation show that interactions between climate forcings could have strong non-linear effects. Third, we presently do not have sufficient wetland methane observation datasets adequate to evaluate model fluxes at a spatial scale comparable to model grid cells (commonly 0.5°). This limitation severely restricts our ability to model global wetland CH4 emissions with confidence. Our simulated wetland extents are also difficult to evaluate due to extensive disagreements between wetland mapping and remotely sensed inundation datasets. Fourth, the large range in predicted CH4 emission rates leads to the conclusion that there is both substantial parameter and structural uncertainty in large-scale CH4 emission models, even after uncertainties in wetland areas are accounted for.