641 research outputs found

    An Exploration of Environmental Technology Transition from the Laboratory to the Field

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    Environmental policy, social factors, individual behavior, and environmental technologies are key factors in improving the current condition of the environment. The Department of Defense (DoD) is not immune to these aspects, as its actions have and will continue to impact the environment in which they conduct operations. The objective of this research is to analyze the environmental technology aspect of improving environmental conditions. Of particular interest, what barriers and bridges are encountered when an Air Force laboratory transitions environmental technologies to an end-user: operational field organization or major weapon system. The research employs a case study methodology to analyze five environmental technology transition efforts within the Air Force. Several key findings identify barriers and bridges specific to the transition of environmental technologies. They include: oversight of environmental protection agencies, the difficulty in clearly defining the end-user, and the need to demonstrate environmental technologies to potential end-users. Further analysis of the case studies indicate that many of the barriers and bridges encountered in the transition of environmental technologies are also encountered in the transition of general technologies. In addition, the researcher provides recommendations for change, and offers future opportunities for research in the area of environmental technology transition

    Mott Insulator - Superfluid Transitions in a Two Band Model at Finite Temperature and Possible Application to Supersolid 4He

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    We study Mott insulator - superfluid transition in a two-band boson Hubbard model, which can be mapped onto a spin-1/2 XY model with spins coupled to an additional Ising degree of freedom. By using a modified mean field theory that include the effects of phase fluctuations, we show that the transition is first order at both zero and finite temperatures. On the Mott insulator side, there may be reentrance in phase transition. These features are consequences of the underlying transition between competing defect poor and defect rich phases. The relevance of the model and our results to supersolid 4He and cold bosonic atoms in optical lattices are discussed

    The Relationship between Cost Analysis and Program Management

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    Cost analysis if often viewed as applying basic principles and cost methodologies to determine total system cost. These finished estimates then flow into a decision making process and the cost estimator leaves the stage. Reality shows that the cost estimator is actually one of the main contributors to the decision making process. Our introduction to this special issue explores the areas where cost estimating plays a major role in program management in areas beyond the normal program estimate. We have included articles that show the key role estimators can play in source selection strategies and evaluation; cost of delay analysis for management decisions, earned value management methods to predict program costs; decision criteria to rank competing projects that complement traditional cost-based methods; and a new methodology for determining research and development budget profiles

    Humanized mice in studying efficacy and mechanisms of PD-1-targeted cancer immunotherapy

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    Establishment of an in vivo small animal model of human tumor and human immune system interaction would enable preclinical investigations into the mechanisms underlying cancer immunotherapy. To this end, nonobese diabetic (NOD).Cg- Prkdc(scid)IL2rg(tm1Wjl)/Sz (null; NSG) mice were transplanted with human (h)CD34(+) hematopoietic progenitor and stem cells, which leads to the development of human hematopoietic and immune systems [humanized NSG (HuNSG)]. HuNSG mice received human leukocyte antigen partially matched tumor implants from patient-derived xenografts [PDX; non-small cell lung cancer (NSCLC), sarcoma, bladder cancer, and triple-negative breast cancer (TNBC)] or from a TNBC cell line-derived xenograft (CDX). Tumor growth curves were similar in HuNSG compared with nonhuman immune-engrafted NSG mice. Treatment with pembrolizumab, which targets programmed cell death protein 1, produced significant growth inhibition in both CDX and PDX tumors in HuNSG but not in NSG mice. Finally, inhibition of tumor growth was dependent on hCD8(+) T cells, as demonstrated by antibody-mediated depletion. Thus, tumor-bearing HuNSG mice may represent an important, new model for preclinical immunotherapy research

    In vivo correction of anaemia in beta-thalassemic mice by gammaPNA-mediated gene editing with nanoparticle delivery

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    The blood disorder, beta-thalassaemia, is considered an attractive target for gene correction. Site-specific triplex formation has been shown to induce DNA repair and thereby catalyse genome editing. Here we report that triplex-forming peptide nucleic acids (PNAs) substituted at the gamma position plus stimulation of the stem cell factor (SCF)/c-Kit pathway yielded high levels of gene editing in haematopoietic stem cells (HSCs) in a mouse model of human beta-thalassaemia. Injection of thalassemic mice with SCF plus nanoparticles containing gammaPNAs and donor DNAs ameliorated the disease phenotype, with sustained elevation of blood haemoglobin levels into the normal range, reduced reticulocytosis, reversal of splenomegaly and up to 7% beta-globin gene correction in HSCs, with extremely low off-target effects. The combination of nanoparticle delivery, next generation gammaPNAs and SCF treatment may offer a minimally invasive treatment for genetic disorders of the blood that can be achieved safely and simply by intravenous administration

    Possible glueball production in relativistic heavy-ion collisions

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    Within a thermal model we estimate possible multiplicities of scalar glueballs in central Au+Au collisions at AGS, SPS, RHIC and LHC energies. For the glueball mass in the region 1.5-1.7 GeV, the model predicts on average (per event) 0.5-1.5 glueballs at RHIC and 1.5-4 glueballs at LHC energies. Possible enhancement mechanisms are discussed.Comment: 8 pages, 2 figure

    Chandra Studies of the X-ray Point Source Luminosity Functions of M31

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    Three different M31 disk fields, spanning a range of stellar populations, were observed by Chandra. We report the X-ray point source luminosity function (LF) of each region, and the LF of M31's globular clusters, and compare these with each other and with the LF of the galaxy's bulge. To interpret the results we also consider tracers of the stellar population, such as OB associations and supernova remnants. We find differences in the LFs among the fields, but cannot definitively relate them to the stellar content of the fields. We find that stellar population information, average and maximum source luminosities, X-ray source densities, and slopes of the LF are useful in combination.Comment: 7 pages, 3 figures, accepted for publication in ApJ. Higher-resolution figures available on reques

    Alloimmune Responses of Humanized Mice to Human Pluripotent Stem Cell Therapeutics

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    There is growing interest in using embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC) derivatives for tissue regeneration. However, an increased understanding of human immune responses to stem cell-derived allografts is necessary for maintaining long-term graft persistence. To model this alloimmunity, humanized mice engrafted with human hematopoietic and immune cells could prove to be useful. In this study, an in-depth analysis of graft-infiltrating human lymphocytes and splenocytes revealed that humanized mice incompletely model human immune responses toward allogeneic stem cells and their derivatives. Furthermore, using an allogenized mouse model, we show the feasibility of reconstituting immunodeficient mice with a functional mouse immune system and describe a key role of innate immune cells in the rejection of mouse stem cell allografts

    Transverse momentum diffusion and jet energy loss in non-Abelian plasmas

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    We consider momentum broadening and energy loss of high momentum partons in a hot non-Abelian plasma due to collisions. We solve the coupled system of Wong-Yang-Mills equations on a lattice in real time, including binary hard elastic collisions among the partons. The collision kernel is constructed such that the total collisional energy loss and momentum broadening are lattice spacing independent. We find that the transport coefficient q^\hat{q} corresponding to transverse momentum broadening receives sizable contributions from a power-law tail in the pp_\perp-distribution of high-momentum partons. We establish the scaling of q^\hat{q} and of dE/dxdE/dx with density, temperature and energy in the weak-coupling regime. We also estimate the nuclear modification factor RAAR_{AA} due to elastic energy loss of a jet in a classical Yang-Mills field.Comment: 25 pages, 13 figures, version accepted for publication in PRC, added discussion of R_AA due to elastic energy loss of a jet in a classical Yang-Mills field, updated reference
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