94 research outputs found
Angular correlation of scattered annihilation photons, to test the possibility of hidden variables in quantum theory
Angular correlations of the annihilation photons, Compton scattered by plastic scintillators and detected by means of NaI (T1) crystals, have been measured in order to test the possibility of deviations of the experimental results from the predictions of the quantum theory
The GEYSERS optical testbed: a platform for the integration, validation and demonstration of cloud-based infrastructure services
The recent evolution of cloud services is leading to a new service transformation paradigm to accommodate network infrastructures in a cost-scalable way. In this transformation, the network constitutes the key to efficiently connect users to services and applications. In this paper we describe the deployment, validation and demonstration of the optical integrated testbed for the “GEneralized architecture for dYnamic infrastructure SERviceS” (GEYSERS) project to accommodate such cloud based Infrastructure Services. The GEYSERS testbed is composed of a set of local physical testbeds allocated in the facilities of the GEYSERS partners. It is built up based on the requirements specification, architecture definition and per-layer development that constitutes the whole GEYSERS ecosystem, and validates the procedures on the GEYSERS prototypes. The testbed includes optical devices (layer 1), switches (layer 2), and IT resources deployed in different local testbeds provided by the project partners and interconnected among them to compose the whole testbed layout. The main goal of the GEYSERS testbed is twofold. On one hand, it aims at providing a validation ground for the architecture, concepts and business models proposed by GEYSERS, sustained by two main paradigms: Infrastructure as a Service (IaaS) and the coupled provisioning of optical network and IT resources. On the other hand, it is used as a demonstration platform for testing the software prototypes within the project and to demonstrate to the research and business community the project approach and solutions. In this work, we discuss our experience in the deployment of the testbed and share the results and insights learned from our trials in the process. Additionally, the paper highlights the most relevant experiments carried out in the testbed, aimed at the validation of the overall GEYSERS architecture
TGF-β1 Down-Regulation of NKG2D/DAP10 and 2B4/SAP Expression on Human NK Cells Contributes to HBV Persistence
The mechanism underlying persistent hepatitis B virus (HBV) infection remains unclear. We investigated the role of innate immune responses to persistent HBV infection in 154 HBV-infected patients and 95 healthy controls. The expression of NKG2D- and 2B4-activating receptors on NK cells was significantly decreased, and moreover, the expression of DAP10 and SAP, the intracellular adaptor proteins of NKG2D and 2B4 (respectively), were lower, which then impaired NK cell-mediated cytotoxic capacity and interferon-γ production. Higher concentrations of transforming growth factor-beta 1 (TGF-β1) were found in sera from persistently infected HBV patients. TGF-β1 down-regulated the expression of NKG2D and 2B4 on NK cells in our in vitro study, leading to an impairment of their effector functions. Anti-TGF-β1 antibodies could restore the expression of NKG2D and 2B4 on NK cells in vitro. Furthermore, TGF-β1 induced cell-cycle arrest in NK cells by up-regulating the expression of p15 and p21 in NK cells from immunotolerant (IT) patients. We conclude that TGF-β1 may reduce the expression of NKG2D/DAP10 and 2B4/SAP, and those IT patients who are deficient in these double-activating signals have impaired NK cell function, which is correlated with persistent HBV infection
UNIVERSITY TRANSPORTATION SURVEY: TRANSPORTATION IN UNIVERSITY COMMUNITIES
Universities and transit agencies across the United States have been finding innovative ways of providing and financing mobility services on and around university campuses. Many transit agencies are providing substantially more service and moving substantially more riders than their counterparts in nonuniversity environments. Determining what types of relationships exist between transit performance and university policies or practices is the research premise. To that end, the purpose is to document the types of transportation policies, demographics, and land use characteristics that exist on university campuses, and to examine the relationship between transit performance, land use on university campuses, types of university communities, university transportation and parking policies, and student demographics. These characteristics of university transportation systems were examined through demographic data and a mailed questionnaire. The questionnaire was sent to 48 universities and transit agencies across the United States, with 23 responding with enough valid data and information to be included in the study. It has been demonstrated in a significant number of university communities across the country that transit performance is enhanced dramatically by certain fare policies. However, that enhancement differs from one community to the next. It is believed that the answer to maximizing transit performance can be found in a combination of factors and that the optimum mix can be identified empirically
Laboratory tests of an anisotropic-grid timber bridge
Research and development was conducted on a prototype timber bridge technology developed for rural bridge sites. The work included conception, computer modeling, laboratory load tests of a reduced size specimen, field construction of a pilot bridge and field load testing. This paper describes the laboratory load test phase. Three loadings comprised of four concentrated loads simulating a truck wheel pattern were conducted. Results of preliminary analytical simulation work is also described. The laboratory specimen demonstrated the structural effectiveness of the concept and led to the final design and implementation of the pilot field bridge. (c) 2005 Elsevier Ltd. All rights reserved
Laboratory tests of composite wood-concrete beams
Exploratory research related to the effectiveness of layered composite solid wood-concrete floor systems is described. Rectangular beams comprised of a concrete layer atop a solid dimension lumber layer were load tested. Interlayer force transfer is accomplished by bearing in a notched shear key. A vertical anchor is utilized to restore tightness of the notch after the concrete cures. Test results indicated the structural merit of the concept based on the degree of partial composite action achieved. (C) 2007 Elsevier Ltd. All rights reserved
Investigation of notched composite wood-concrete connections
An initial stage of research on the feasibility of a composite concrete-wood commercial floors system is described. The floors are comprised of concrete placed atop a solid layer of dimension lumber. A notched shear key/anchor detail is used for interlayer connection. This connection detail transfers interlayer force by bearing adjacent materials in the notch. The anchor serves to tighten the layers after curing of the concrete. Initial testing included pull-out tests on the anchor and interlayer slip tests to define the geometry of the connection detail. Test results indicated the structural merit of the connection concept compared to the use of ordinary mechanical connectors
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