4,272 research outputs found
Data management study, volume 5. Appendix J - Contractor data package procurement and contracting /PC/ Final report
Contractor data package for administration of procurement and contracting of Voyager spacecraft system
Radiative Corrections to K^0_{l3} Decays
We calculate the long-distance radiative corrections \delta^e_{LD} and
\delta^{\mu}_{LD} to the K^0 -> \pi^- e^+ \nu_e and the K^0 -> pi^- \mu^+
\nu_{\mu} decay rates. This analysis includes contributions to the
long-distance radiative corrections from outside the kinematically-allowed
three-body Dalitz region and tests the sensitivity of the radiative corrections
to the hadronic K-pi form factors. A program, KLOR, was written to numerically
evaluate the radiative corrections and to generate Monte Carlo events for
experimental acceptance studies. The K^0_{e3} and the K^0_{\mu 3} long-distance
radiative correction parameters are determined to be (1.3 +/- 0.3)% and (1.9
+/- 0.3)%, respectively. We also present predictions for the fraction of
radiative K^0_{l3} events satisfying various requirements on final-state photon
kinematics.Comment: Accepted in Annals of Physics; 16 pages, 8 figures; v3 contains minor
text change
Building Trust and Visibility Through Community-Based Participatory Research at Rural Minority-Serving Institutions
Universities and colleges are producers of knowledge and play an important role in shaping culture, policy, political agendas, and in many ways, the flow of resources to communities. To increase the potential for those living in rural communities, as well as the vibrancy of these communities, researchers can and should center rural voices, ground the production of knowledge in these voices, and address power imbalances in research and practice. Minority Serving Institutions (MSIs) play a crucial role in this strategy for empowering rural communities. In our latest research brief, the authors explore how rural MSIs and approaches to community based participatory research can be used to better understand MSIs' nature and practices
Enhanced Integrin α4β1-Mediated Adhesion Contributes to a Mobilization Defect of Endothelial Progenitor Cells in Diabetes.
Diabetes is associated with a deficit of circulating endothelial progenitor cells (EPCs), which has been attributed to their defective mobilization from the bone marrow. The basis for this mobilization defect is not completely understood, and we sought to determine if hyperglycemic conditions enhanced EPC adhesion. We found that culturing EPCs in high glucose media increased adhesion to bone marrow stromal cells. This enhanced adhesion was associated with decreased expression of protein kinase A regulatory subunit 1β (PRKAR1β), activation of protein kinase A (PKA), and phosphorylation of α4-integrin on serine 988. This potentiated adhesion was reversed by treatment with a PKA inhibitor, overexpression of PRKAR1β, or expression of a phosphorylation-defective α4-integrin variant (α4[S988A]). Using a model of type 1 diabetes, we showed that α4(S988A)-expressing mice have more circulating EPCs than their wild-type counterparts. Moreover, diabetic α4(S988A) mice demonstrate enhanced revascularization after hind limb ischemia. Thus, we have identified a novel signaling mechanism activating PKA in diabetes (downregulation of an inhibitory regulatory subunit) that leads to deficits of circulating EPCs and impaired vascular repair, which could be reversed by α4-integrin mutation
Superconducting properties of ultrathin Bi2Sr2CaCu2O8+x single crystals
We use Ar-ion milling to thin Bi2212 single crystals down to a few nanometers
or one-to-two (CuO2)2 layers. With decreasing the thickness, superconducting
transition temperature gradually decreases to zero and the in-plane resistivity
increases to large values indicating the existence of a
superconductor-insulator transition in ultrathin Bi2212 single crystals.Comment: 17 pages, 6 figures, to appear in J. Appl. Phys. 98(3) 200
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Potential for entrainment of sodium into expanding multiphase HCDA bubbles by Rayleigh-Taylor instability
The ''termination phase'' of an energetic hypothetical core disruptive accident (HCDA) in liquid-metal fast breeder reactors is characterized by expansion of a high-pressure, high-temperature multiphase bubble against the overlying pool of sodium. A number of entrainment mechanisms have been proposed to explain the entrainment rates observed in various experiments. (JDB
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Observations on hydrogen generation in vicinity of the reactor cavity during the Direct Containment Heating scenario
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A reassessment of the potential for an alpha-mode containment failure and a review of the current understanding of broader fuel-coolant interaction issues. Second steam explosion review group workshop
This report summarizes the review and evaluation by experts of the current understanding of the molten fuel-coolant interaction (FCI) issues covering the complete spectrum of interactions, i.e., from mild quenching to very energetic interactions including those that could lead to the alpha-mode containment failure. Of the eleven experts polled, all but two concluded that the alpha-mode failure issue was resolved from a risk perspective, meaning that this mode of failure is of very low probability, that it is of little or no significance to the overall risk from a nuclear power plant, and that any further reduction in residual uncertainties is not likely to change the probability in an appreciable manner. To a lesser degree, discussions also took place on the broader FCI issues such as mild quenching of core melt during non-explosive FCI, and shock loading of lower head and ex-vessel support structures arising from explosive localized FCIs. These latter issues are relevant with regard to determining the efficacy of certain accident management strategies for operating reactors as well as for advanced light water reactors. The experts reviewed the status of understanding of the FCI phenomena in the context of these broader issues, identified residual uncertainties in the understanding, and recommended future research (both experimental and analytical) to reduce the uncertainties
Updating DL-Lite ontologies through first-order queries
In this paper we study instance-level update in DL-LiteA, the description logic underlying the OWL 2 QL standard. In particular we focus on formula-based approaches to ABox insertion and deletion. We show that DL-LiteA, which is well-known for enjoying first-order rewritability of query answering, enjoys a first-order rewritability property also for updates. That is, every update can be reformulated into a set of insertion and deletion instructions computable through a nonrecursive datalog program. Such a program is readily translatable into a first-order query over the ABox considered as a database, and hence into SQL. By exploiting this result, we implement an update component for DLLiteA-based systems and perform some experiments showing that the approach works in practice.Peer ReviewedPostprint (author's final draft
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