4,303 research outputs found

    Conservative treatment of boundary interfaces for overlaid grids and multi-level grid adaptations

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    Conservative algorithms for boundary interfaces of overlaid grids are presented. The basic method is zeroth order, and is extended to a higher order method using interpolation and subcell decomposition. The present method, strictly based on a conservative constraint, is tested with overlaid grids for various applications of unsteady and steady supersonic inviscid flows with strong shock waves. The algorithm is also applied to a multi-level grid adaptation in which the next level finer grid is overlaid on the coarse base grid with an arbitrary orientation

    Stochastic models for quality of service of component connectors

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    The intensifying need for scalable software has motivated modular development and using systems distributed over networks to implement large-scale applications. In Service-oriented Computing, distributed services are composed to provide large-scale services with a specific functionality. In this way, reusability of existing services can be increased. However, due to the heterogeneity of distributed software systems, software composition is not easy and requires additional mechanisms to impose some form of a coordination on a distributed software system. Besides functional correctness, a composed service must satisfy various quantitative requirements for its clients, which are generically called its quality of service (QoS). Particularly, it is tricky to obtain the overall QoS of a composed service even if the QoS information of its constituent distributed services is given. In this thesis, we propose Stochastic Reo to specify software composition with QoS aspects and its compositional semantic models. They are also used as intermediate models to generate their corresponding stochastic models for practical analysis. Based on this, we have implemented the tool Reo2MC. Using Reo2MC, we have modeled and analyzed an industrial software, the ASK system. Its analysis results provided the best cost-effective resource utilization and some suggestions to improve the performance of the system.UBL - phd migration 201

    Economic and Environmental Impacts of Cellulosic Feedstock Production in Minnesota

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    Crop Production/Industries, Environmental Economics and Policy, Production Economics,

    Electrogenic transport and K(+) ion channel expression by the human endolymphatic sac epithelium.

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    The endolymphatic sac (ES) is a cystic organ that is a part of the inner ear and is connected to the cochlea and vestibule. The ES is thought to be involved in inner ear ion homeostasis and fluid volume regulation for the maintenance of hearing and balance function. Many ion channels, transporters, and exchangers have been identified in the ES luminal epithelium, mainly in animal studies, but there has been no functional study investigating ion transport using human ES tissue. We designed the first functional experiments on electrogenic transport in human ES and investigated the contribution of K(+) channels in the electrogenic transport, which has been rarely identified, even in animal studies, using electrophysiological/pharmacological and molecular biological methods. As a result, we identified functional and molecular evidence for the essential participation of K(+) channels in the electrogenic transport of human ES epithelium. The identified K(+) channels involved in the electrogenic transport were KCNN2, KCNJ14, KCNK2, and KCNK6, and the K(+) transports via those channels are thought to play an important role in the maintenance of the unique ionic milieu of the inner ear fluid

    Comparison of Dst Forecast Models for Intense Geomagnetic Storms

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    We have compared six disturbance storm time (Dst) forecast models using 63 intense geomagnetic storms (Dst <=100 nT) that occurred from 1998 to 2006. For comparison, we estimated linear correlation coefficients and RMS errors between the observed Dst data and the predicted Dst during the geomagnetic storm period as well as the difference of the value of minimum Dst (Delta Dst(sub min)) and the difference in the absolute value of Dst minimum time (Delta t(sub Dst)) between the observed and the predicted. As a result, we found that the model by Temerin and Li gives the best prediction for all parameters when all 63 events are considered. The model gives the average values: the linear correlation coefficient of 0.94, the RMS error of 14.8 nT, the Delta Dst(sub min) of 7.7 nT, and the absolute value of Delta t(sub Dst) of 1.5 hour. For further comparison, we classified the storm events into two groups according to the magnitude of Dst. We found that the model of Temerin and Lee is better than the other models for the events having 100 <= Dst < 200 nT, and three recent models (the model of Wang et al., the model of Temerin and Li, and the model of Boynton et al.) are better than the other three models for the events having Dst <= 200 nT

    Does natural killer cell deficiency (NKD) increase the risk of cancer? NKD may increase the risk of some virus induced cancer

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    Natural killer cell deficiency (NKD) is a primary immunodeficiency where the main defect lies in CD56+CD3− natural killer (NK) cells which mediate cytotoxicity against tumors. Most cases are observed in children and adolescents with recurrent viral infections and cancer. GATA2 and MCM4 mutations are found in NKD patients with cancer. However, the question remains unclear whether NKD increases the risk of cancer. Mutations in the second zinc finger of GATA2 cause both NKD and haematopoietic malignancies. MCM4 splice site mutations are found in NKD patients and they increase susceptibility to DNA instability during replication. IRF8, RTEL1, and FCGR3A mutations are associated with NKD but their associations with cancer are unknown. Based on the studies, it is hypothesized that genetic mutations alone are sufficient to cause cancer. However, a number of NKD patients developed oncogenic viral infections which progressed into cancer. Here, we review the evidence of genetic mutations responsible for both NKD and cancer to identify whether NKD contributes to development of cancer. The findings provide insights into the role of NK cells in the prevention of cancer and the significance of assessing NK cell functions in susceptible individuals.Publisher PDFPeer reviewe

    A Compositional Semantics for Stochastic Reo Connectors

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    In this paper we present a compositional semantics for the channel-based coordination language Reo which enables the analysis of quality of service (QoS) properties of service compositions. For this purpose, we annotate Reo channels with stochastic delay rates and explicitly model data-arrival rates at the boundary of a connector, to capture its interaction with the services that comprise its environment. We propose Stochastic Reo automata as an extension of Reo automata, in order to compositionally derive a QoS-aware semantics for Reo. We further present a translation of Stochastic Reo automata to Continuous-Time Markov Chains (CTMCs). This translation enables us to use third-party CTMC verification tools to do an end-to-end performance analysis of service compositions. As a case study, we are currentl
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