Science.gov

Sample records for nas escalas espaciais

  1. Columbia Project at NAS

    NASA Technical Reports Server (NTRS)

    Thigpen, Bill

    2004-01-01

    The Columbia Project at NAS is the construction and utilization of one of the world's most powerful compute resources. With 10,240 processors spread across 20512- processor nodes. this system provides NASA with an unparalleled capacity for capability processing. This demonstration will focus on describing the process of fielding this system while providing the NAS community with an ever-increasing capability during construction.

  2. Numerical Aerodynamic Simulation (NAS)

    NASA Technical Reports Server (NTRS)

    Peterson, V. L.; Ballhaus, W. F., Jr.; Bailey, F. R.

    1983-01-01

    The history of the Numerical Aerodynamic Simulation Program, which is designed to provide a leading-edge capability to computational aerodynamicists, is traced back to its origin in 1975. Factors motivating its development and examples of solutions to successively refined forms of the governing equations are presented. The NAS Processing System Network and each of its eight subsystems are described in terms of function and initial performance goals. A proposed usage allocation policy is discussed and some initial problems being readied for solution on the NAS system are identified.

  3. NATIONAL ALCOHOL SURVEY (NAS)

    EPA Science Inventory

    National Alcohol Survey (NAS) is designed to assess the trends in drinking practices and problems in the national population, including attitudes, norms, treatment and experiences and adverse consequences. It also studies the effects of public policy on drinking practices (i.e., ...

  4. The NAS Parallel Benchmarks

    SciTech Connect

    Bailey, David H.

    2009-11-15

    The NAS Parallel Benchmarks (NPB) are a suite of parallel computer performance benchmarks. They were originally developed at the NASA Ames Research Center in 1991 to assess high-end parallel supercomputers. Although they are no longer used as widely as they once were for comparing high-end system performance, they continue to be studied and analyzed a great deal in the high-performance computing community. The acronym 'NAS' originally stood for the Numerical Aeronautical Simulation Program at NASA Ames. The name of this organization was subsequently changed to the Numerical Aerospace Simulation Program, and more recently to the NASA Advanced Supercomputing Center, although the acronym remains 'NAS.' The developers of the original NPB suite were David H. Bailey, Eric Barszcz, John Barton, David Browning, Russell Carter, LeoDagum, Rod Fatoohi, Samuel Fineberg, Paul Frederickson, Thomas Lasinski, Rob Schreiber, Horst Simon, V. Venkatakrishnan and Sisira Weeratunga. The original NAS Parallel Benchmarks consisted of eight individual benchmark problems, each of which focused on some aspect of scientific computing. The principal focus was in computational aerophysics, although most of these benchmarks have much broader relevance, since in a much larger sense they are typical of many real-world scientific computing applications. The NPB suite grew out of the need for a more rational procedure to select new supercomputers for acquisition by NASA. The emergence of commercially available highly parallel computer systems in the late 1980s offered an attractive alternative to parallel vector supercomputers that had been the mainstay of high-end scientific computing. However, the introduction of highly parallel systems was accompanied by a regrettable level of hype, not only on the part of the commercial vendors but even, in some cases, by scientists using the systems. As a result, it was difficult to discern whether the new systems offered any fundamental performance advantage over vector supercomputers, and, if so, which of the parallel offerings would be most useful in real-world scientific computation. In part to draw attention to some of the performance reporting abuses prevalent at the time, the present author wrote a humorous essay 'Twelve Ways to Fool the Masses,' which described in a light-hearted way a number of the questionable ways in which both vendor marketing people and scientists were inflating and distorting their performance results. All of this underscored the need for an objective and scientifically defensible measure to compare performance on these systems.

  5. NAS Parallel Benchmarks Results

    NASA Technical Reports Server (NTRS)

    Subhash, Saini; Bailey, David H.; Lasinski, T. A. (Technical Monitor)

    1995-01-01

    The NAS Parallel Benchmarks (NPB) were developed in 1991 at NASA Ames Research Center to study the performance of parallel supercomputers. The eight benchmark problems are specified in a pencil and paper fashion i.e. the complete details of the problem to be solved are given in a technical document, and except for a few restrictions, benchmarkers are free to select the language constructs and implementation techniques best suited for a particular system. In this paper, we present new NPB performance results for the following systems: (a) Parallel-Vector Processors: Cray C90, Cray T'90 and Fujitsu VPP500; (b) Highly Parallel Processors: Cray T3D, IBM SP2 and IBM SP-TN2 (Thin Nodes 2); (c) Symmetric Multiprocessing Processors: Convex Exemplar SPP1000, Cray J90, DEC Alpha Server 8400 5/300, and SGI Power Challenge XL. We also present sustained performance per dollar for Class B LU, SP and BT benchmarks. We also mention NAS future plans of NPB.

  6. Observações simultâneas no óptico e infravermelho próximo dos BL Lacs PKS 2005-489 e PKS 2155-304 em diversas escalas de tempo

    NASA Astrophysics Data System (ADS)

    Dominici, T. P.; Abraham, Z.; Galo, A. L.

    2003-08-01

    A existência de variações rápidas de brilho em alguns blazares é um fenômeno bem comprovado, mas até agora não sabemos ao certo quais são os mecanismos físicos envolvidos. A maior dificuldade é a ausência de observações multibanda simultâneas que poderiam fornecer vínculos aos modelos. Buscando colaborar com a discussão estudamos o comportamento de dois BL Lacs, PKS 2005-489 e PKS 2155-304, em relação à variabilidade em diversas escalas de tempo, de poucos minutos até vários meses, com observações simultâneas em seis bandas espectrais (óptico e infravermelho próximo). Para tanto dois telescópios do LNA foram utilizados em conjunto nas campanhas observacionais realizadas em 2001 e 2002, cujos resultados são apresentados aqui. As duas fontes apresentaram características bastante diferentes, inclusive em relação à existência de variabilidade nos índices espectrais. Particularmente, registramos a primeira detecção de variações em escalas de tempo da ordem de poucos minutos em PKS 2005-489, com evidências da presença de um atraso entre as curvas de luz nas bandas V e R e a variação em R ocorrendo antes (o contrário do esperado no modelo de shock-in-jet). Em PKS 2155-304 detectamos pela primeira vez variabilidade em escalas de tempo de poucos minutos no infravermelho em um AGN. As observações indicam que as variações de brilho em blazares são o resultado da ação de mais de um fenômeno, especialmente em escalas de tempo muito curtas. Alguns cenários físicos são sugeridos para explicar os resultados observacionais.

  7. NASA's UAS NAS Access Project

    NASA Technical Reports Server (NTRS)

    Johnson, Charles W.

    2011-01-01

    The vision of the Unmanned Aircraft System (UAS) Integration in the National Airspace System (NAS) Project is "A global transportation system which allows routine access for all classes of UAS." The goal of the UAS Integration in the NAS Project is to "contribute capabilities that reduce technical barriers related to the safety and operational challenges associated with enabling routine UAS access to the NAS." This goal will be accomplished through a two-phased approach based on development of system-level integration of key concepts, technologies and/or procedures, and demonstrations of integrated capabilities in an operationally relevant environment. Phase 1 will take place the first two years of the Project and Phase 2 will take place the following three years. The Phase 1 and 2 technical objectives are: Phase 1: Developing a gap analysis between current state of the art and the Next Generation Air Transportation System (NextGen) UAS Concept of Operations . Validating the key technical areas identified by this Project . Conducting initial modeling, simulation, and flight testing activities . Completing Sub-project Phase 1 deliverables (spectrum requirements, comparative analysis of certification methodologies, etc.) and continue Phase 2 preparation (infrastructure, tools, etc.) Phase 2: Providing regulators with a methodology for developing airworthiness requirements for UAS, and data to support development of certifications standards and regulatory guidance . Providing systems-level, integrated testing of concepts and/or capabilities that address barriers to routine access to the NAS. Through simulation and flight testing, address issues including separation assurance, communications requirements, and human systems integration in operationally relevant environments. The UAS in the NAS Project will demonstrate solutions in specific technology areas, which will address operational/safety issues related to UAS access to the NAS. Since the resource allocation for this Project is limited ($150M over the five years), the focus is on reducing the technical barriers where NASA has unique capabilities. As a result, technical areas, such as Sense and Avoid (SAA) and beyond line of sight command and control will not be addressed. While these are critical barriers to UAS access, currently, there is a great deal of global effort being exercised to address these challenge areas. Instead, specific technology development in areas where there is certainty that NASA can advance the research to high technology readiness levels will be the Project's focus. Specific sub-projects include Separation Assurance, Human Systems Integration, Communications, Certification, and Integrated Test and Evaluation. Each sub-project will transfer technologies to relevant key stakeholders and decision makers through research transition teams, technology forums, or through other analogous means.

  8. NAS Panel faults export controls

    NASA Astrophysics Data System (ADS)

    Katzoff, Judith A.

    A study prepared by a top-level panel says that current export controls on militarily sensitive U.S. technology may be “overcorrecting” previous weaknesses in that system, resulting in “a complex and confusing control system” that makes it more difficult for U.S. businesses to compete in international markets. Moreover, this control system has “an increasingly corrosive effect” on U.S. relations with allies. The panel recommended that the United States concentrate more effort on bringing about uniformity in the export control policies of countries belonging to the Coordinating Committee on Multilateral Export Controls (CoCom), i.e., most of the member nations in NATO (the North Atlantic Treaty Organization) and Japan.The 21-member panel was appointed by the Committee on Science, Engineering, and Public Policy (COSEPUP), a joint unit of the National Academy of Sciences (NAS), the National Academy of Engineering (NAE), and the Institute of Medicine (IOM). The panel, composed of administrators, researchers, and former government officials, was chaired by AGU member Lew Allen, Jr., director of the Jet Propulsion Laboratory (Pasadena, Calif.) and former chief of staff of the U.S. Air Force. Their report was supported by NAS funds, by a number of private organizations (including AGU), by the U.S. Departments of Commerce, Defense, Energy, and State, by the National Science Foundation, and by the National Aeronautics and Space Administration.

  9. The NAS Computational Aerosciences Archive

    NASA Technical Reports Server (NTRS)

    Miceli, Kristina D.; Globus, Al; Lasinski, T. A. (Technical Monitor)

    1995-01-01

    In order to further the state-of-the-art in computational aerosciences (CAS) technology, researchers must be able to gather and understand existing work in the field. One aspect of this information gathering is studying published work available in scientific journals and conference proceedings. However, current scientific publications are very limited in the type and amount of information that they can disseminate. Information is typically restricted to text, a few images, and a bibliography list. Additional information that might be useful to the researcher, such as additional visual results, referenced papers, and datasets, are not available. New forms of electronic publication, such as the World Wide Web (WWW), limit publication size only by available disk space and data transmission bandwidth, both of which are improving rapidly. The Numerical Aerodynamic Simulation (NAS) Systems Division at NASA Ames Research Center is in the process of creating an archive of CAS information on the WWW. This archive will be based on the large amount of information produced by researchers associated with the NAS facility. The archive will contain technical summaries and reports of research performed on NAS supercomputers, visual results (images, animations, visualization system scripts), datasets, and any other supporting meta-information. This information will be available via the WWW through the NAS homepage, located at http://www.nas.nasa.gov/, fully indexed for searching. The main components of the archive are technical summaries and reports, visual results, and datasets. Technical summaries are gathered every year by researchers who have been allotted resources on NAS supercomputers. These summaries, together with supporting visual results and references, are browsable by interested researchers. Referenced papers made available by researchers can be accessed through hypertext links. Technical reports are in-depth accounts of tools and applications research projects performed by NAS staff members and collaborators. Visual results, which may be available in the form of images, animations, and/or visualization scripts, are generated by researchers with respect to a certain research project, depicting dataset features that were determined important by the investigating researcher. For example, script files for visualization systems (e.g. FAST, PLOT3D, AVS) are provided to create visualizations on the user's local workstation to elucidate the key points of the numerical study. Users can then interact with the data starting where the investigator left off. Datasets are intended to give researchers an opportunity to understand previous work, 'mine' solutions for new information (for example, have you ever read a paper thinking "I wonder what the helicity density looks like?"), compare new techniques with older results, collaborate with remote colleagues, and perform validation. Supporting meta-information associated with the research projects is also important to provide additional context for research projects. This may include information such as the software used in the simulation (e.g. grid generators, flow solvers, visualization). In addition to serving the CAS research community, the information archive will also be helpful to students, visualization system developers and researchers, and management. Students (of any age) can use the data to study fluid dynamics, compare results from different flow solvers, learn about meshing techniques, etc., leading to better informed individuals. For these users it is particularly important that visualization be integrated into dataset archives. Visualization researchers can use dataset archives to test algorithms and techniques, leading to better visualization systems, Management can use the data to figure what is really going on behind the viewgraphs. All users will benefit from fast, easy, and convenient access to CFD datasets. The CAS information archive hopes to serve as a useful resource to those interested in computational sciences. At present, only information that may be distributed internationally is made available via the archive. Studies are underway to determine security requirements and solutions to make additional information available. By providing access to the archive via the WWW, the process of information gathering can be more productive and fruitful due to ease of access and ability to manage many different types of information. As the archive grows, additional resources from outside NAS will be added, providing a dynamic source of research results.

  10. Greenhouse policy study from NAS

    NASA Astrophysics Data System (ADS)

    Maggs, William Ward

    The National Academy of Sciences will produce a study for the Environmental Protection Agency on policy responses to global warming. The report is due out before the end of 1990.Dan J. Evans, former U.S. Senator and former Governor of Washington, will chair a panel of the Commission on Science, Engineering, and Public Policy, a body of the councils of the NAS, National Academy of Engineering, and Institute of Medicine. Evans is a registered civil engineer and previously chaired the Pacific Northwest Electric Power and Conservation Planning Council.The 13-person panel includes AGU members Stephen Schneider of the National Center for Atmospheric Research and Robert Frosch, Vice President of Research Laboratores at General Motors Corp., Jessica Mathews, Vice President of the World Resources Institute, and Sir Crispin Tickell, the United Kingdom's Ambassador to the United Nations.

  11. Supercomputing 2002: NAS Demo Abstracts

    NASA Technical Reports Server (NTRS)

    Parks, John (Technical Monitor)

    2002-01-01

    The hyperwall is a new concept in visual supercomputing, conceived and developed by the NAS Exploratory Computing Group. The hyperwall will allow simultaneous and coordinated visualization and interaction of an array of processes, such as a the computations of a parameter study or the parallel evolutions of a genetic algorithm population. Making over 65 million pixels available to the user, the hyperwall will enable and elicit qualitatively new ways of leveraging computers to accomplish science. It is currently still unclear whether we will be able to transport the hyperwall to SC02. The crucial display frame still has not been completed by the metal fabrication shop, although they promised an August delivery. Also, we are still working the fragile node issue, which may require transplantation of the compute nodes from the present 2U cases into 3U cases. This modification will increase the present 3-rack configuration to 5 racks.

  12. Mapa Geologico de Venezuela a Escala 1:750,000

    USGS Publications Warehouse

    Hackley, Paul C.; Urbani, Franco; Karlsen, Alex W.; Garrity, Christopher P.

    2006-01-01

    Se presenta un mapa geologico digital de Venezuela sobre un fondo de relieve sombreado. Los datos geologicos e hidrologicos del norte del rio Orinoco proceden de la digitalizacion de mapas geologicos en papel a escala 1:500.000. Estos datos fueron integrados con el mapa geologico digital del Escudo de Guayana Venezolano, a su vez derivado de hojas en papel a escala 1:500.000. La informacion sobre los tipos de fallas mostrados en el mapa es igual que en las fuentes originales. Los poligonos geologicos fueron atribuidos por edad, litologia y nombre de la unidad siguiendo el Codigo geologico de Venezuela. Se incorporaron revisiones significativas de la geologia de la Cordillera de la Costa a partir de las nuevas hojas integradas a escala 1:25.000. Toda esta informacion geologico-estructural se sobrepuso a una imagen de relieve sombreado, producida por el procesamiento de los datos de radar interferometrico con 90 m (3 arcosegundos) de resolucion espacial obtenidos por la mision topografica de radar del transbordador espacial (SRTM). Las areas de la base de datos del SRTM carentes de informacion fueron llenadas por medio de la interpolacion de los datos de las celdas adyacentes. Para producir la imagen de relieve sombreado se uso una direccion de iluminacion de 315 deg con un angulo de 65 deg sobre el horizonte. La proyeccion usada en el mapa es conica equidistante, con latitudes de 4 y 9 deg norte como paralelos estandar y una longitud de 66 deg al oeste como meridiano central. Los datos en el mapa proceden primordialment de hojas a escala 1:500.000 y el producto esta preparado para una impresion optima en escala 1:750.000. Los usuarios pueden obtener ampliaciones mayores, sin embargo no se garantiza la precision del mapa a escalas mas detalladas. Especialmente en la region de Guayana, al sobreponer los mapas geologicos sobre la reciente imagen SRTM, se notan grandes discrepancias no sistematicas tanto en contactos como en fallas. Esto es debido a que los mapas geologicos de Guayana tienen como base topografica las imagenes de radar de vision lateral (SLAR), con muy control de campo de los a?os 1970's. La correccion de estos desfases esta planificada para el futuro.

  13. GaInNAs laser gain

    SciTech Connect

    CHOW,WENG W.; JONES,ERIC D.; MODINE,NORMAND A.; KURTZ,STEVEN R.; ALLERMAN,ANDREW A.

    2000-05-23

    The optical gain spectra for GaInNAs/GaAs quantum wells are computed using a microscopic laser theory. From these spectra, the peak gain and carrier radiative decay rate as functions of carrier density are determined. These dependences allow the study of the lasing threshold current density of GaInNAs/GaAs quantum well structures.

  14. NAS-current status and future plans

    NASA Technical Reports Server (NTRS)

    Bailey, F. R.

    1987-01-01

    The Numerical Aerodynamic Simulation (NAS) has met its first major milestone, the NAS Processing System Network (NPSN) Initial Operating Configuration (IOC). The program has met its goal of providing a national supercomputer facility capable of greatly enhancing the Nation's research and development efforts. Furthermore, the program is fulfilling its pathfinder role by defining and implementing a paradigm for supercomputing system environments. The IOC is only the begining and the NAS Program will aggressively continue to develop and implement emerging supercomputer, communications, storage, and software technologies to strengthen computations as a critical element in supporting the Nation's leadership role in aeronautics.

  15. NASA Advanced Supercomputing (NAS) User Services Group

    NASA Technical Reports Server (NTRS)

    Pandori, John; Hamilton, Chris; Niggley, C. E.; Parks, John W. (Technical Monitor)

    2002-01-01

    This viewgraph presentation provides an overview of NAS (NASA Advanced Supercomputing), its goals, and its mainframe computer assets. Also covered are its functions, including systems monitoring and technical support.

  16. Simultaneous Estimation of Hydrochlorothiazide, Hydralazine Hydrochloride, and Reserpine Using PCA, NAS, and NAS-PCA

    PubMed Central

    Sharma, Chetan; Badyal, Pragya Nand; Rawal, Ravindra K.

    2015-01-01

    In this study, new and feasible UV-visible spectrophotometric and multivariate spectrophotometric methods were described for the simultaneous determination of hydrochlorothiazide (HCTZ), hydralazine hydrochloride (H.HCl), and reserpine (RES) in combined pharmaceutical tablets. Methanol was used as a solvent for analysis and the whole UV region was scanned from 200–400 nm. The resolution was obtained by using multivariate methods such as the net analyte signal method (NAS), principal component analysis (PCA), and net analyte signal-principal component analysis (NAS-PCA) applied to the UV spectra of the mixture. The results obtained from all of the three methods were compared. NAS-PCA showed a lot of resolved data as compared to NAS and PCA. Thus, the NAS-PCA technique is a combination of NAS and PCA methods which is advantageous to obtain the information from overlapping results. PMID:26839841

  17. Status and projections of the NAS program

    NASA Technical Reports Server (NTRS)

    Bailey, Frank R.

    1986-01-01

    NASA's Numerical Aerodynamic Simulation (NAS) Program has completed development of the initial operating configuration of the NAS Processing System Network (NPSN). This is the first milestone in the continuing and pathfinding effort to provide state-of-the-art supercomputing for aeronautics research and development. The NPSN, available to a nation-wide community of remote users, provides a uniform UNIX environment over a network of host computers ranging from the Cray-2 supercomputer to advanced scientific workstations. This system, coupled with a vendor-independent base of common user interface and network software, presents a new paradigm for supercomputing environments. Background leading to the NAS program, its programmatic goals and strategies, technical goals and objectives, and the development activities leading to the current NPSN configuration are presented. Program status, near-term plans, and plans for the next major milestone, the extended operating configuration, are also discussed.

  18. Antimycobacterial Activity and Mechanism of Action of NAS-91?

    PubMed Central

    Gratraud, Paul; Surolia, Namita; Besra, Gurdyal S.; Surolia, Avadhesha; Kremer, Laurent

    2008-01-01

    The antimalarial agents NAS-91 and NAS-21 were found to express potent antimycobacterial activity, NAS-91 being more active than NAS-21. They partially inhibited mycolic acid biosynthesis and profoundly altered oleic acid production. The development of a cell-free assay for ?9-desaturase activity allowed direct demonstration of the inhibition of oleic acid biosynthesis by these compounds. PMID:18086849

  19. Busca de estruturas em grandes escalas em altos redshifts

    NASA Astrophysics Data System (ADS)

    Boris, N. V.; Sodrã©, L., Jr.; Cypriano, E.

    2003-08-01

    A busca por estruturas em grandes escalas (aglomerados de galáxias, por exemplo) é um ativo tópico de pesquisas hoje em dia, pois a detecção de um único aglomerado em altos redshifts pode por vínculos fortes sobre os modelos cosmológicos. Neste projeto estamos fazendo uma busca de estruturas distantes em campos contendo pares de quasares próximos entre si em z Â3 0.9. Os pares de quasares foram extraídos do catálogo de Véron-Cetty & Véron (2001) e estão sendo observados com os telescópios: 2,2m da University of Hawaii (UH), 2,5m do Observatório de Las Campanas e com o GEMINI. Apresentamos aqui a análise preliminar de um par de quasares observado nos filtros i'(7800 Å) e z'(9500 Å) com o GEMINI. A cor (i'-z') mostrou-se útil para detectar objetos "early-type" em redshifts menores que 1.1. No estudo do par 131046+0006/J131055+0008, com redshift ~ 0.9, o uso deste método possibilitou a detecção de sete objetos candidatos a galáxias "early-type". Num mapa da distribuição projetada dos objetos para 22 < i' < 25 observou-se que estas galáxias estão localizadas próximas a um dos quasares e há indícios de que estejam aglomeradas dentro de um área de ~ 6 arcmin2. Se esse for o caso, estes objetos seriam membros de uma estrutura em grande escala. Um outro argumento em favor dessa hipótese é que eles obedecem uma relação do tipo Kormendy (raio equivalente X brilho superficial dentro desse raio), como a apresentada pelas galáxias elípticas em z = 0.

  20. NAS Technical Summaries, March 1993 - February 1994

    NASA Technical Reports Server (NTRS)

    1995-01-01

    NASA created the Numerical Aerodynamic Simulation (NAS) Program in 1987 to focus resources on solving critical problems in aeroscience and related disciplines by utilizing the power of the most advanced supercomputers available. The NAS Program provides scientists with the necessary computing power to solve today's most demanding computational fluid dynamics problems and serves as a pathfinder in integrating leading-edge supercomputing technologies, thus benefitting other supercomputer centers in government and industry. The 1993-94 operational year concluded with 448 high-speed processor projects and 95 parallel projects representing NASA, the Department of Defense, other government agencies, private industry, and universities. This document provides a glimpse at some of the significant scientific results for the year.

  1. Implementation of NAS Parallel Benchmarks in Java

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael; Schultz, Matthew; Jin, Hao-Qiang; Yan, Jerry

    2000-01-01

    A number of features make Java an attractive but a debatable choice for High Performance Computing (HPC). In order to gauge the applicability of Java to the Computational Fluid Dynamics (CFD) we have implemented NAS Parallel Benchmarks in Java. The performance and scalability of the benchmarks point out the areas where improvement in Java compiler technology and in Java thread implementation would move Java closer to Fortran in the competition for CFD applications.

  2. NAS Parallel Benchmarks Results 3-95

    NASA Technical Reports Server (NTRS)

    Saini, Subhash; Bailey, David H.; Walter, Howard (Technical Monitor)

    1995-01-01

    The NAS Parallel Benchmarks (NPB) were developed in 1991 at NASA Ames Research Center to study the performance of parallel supercomputers. The eight benchmark problems are specified in a "pencil and paper" fashion, i.e., the complete details of the problem are given in a NAS technical document. Except for a few restrictions, benchmark implementors are free to select the language constructs and implementation techniques best suited for a particular system. In this paper, we present new NPB performance results for the following systems: (a) Parallel-Vector Processors: CRAY C90, CRAY T90 and Fujitsu VPP500; (b) Highly Parallel Processors: CRAY T3D, IBM SP2-WN (Wide Nodes), and IBM SP2-TN2 (Thin Nodes 2); and (c) Symmetric Multiprocessors: Convex Exemplar SPPIOOO, CRAY J90, DEC Alpha Server 8400 5/300, and SGI Power Challenge XL (75 MHz). We also present sustained performance per dollar for Class B LU, SP and BT benchmarks. We also mention future NAS plans for the NPB.

  3. UAS Integration in the NAS Project - Project Overview

    NASA Technical Reports Server (NTRS)

    Johnson, Chuck

    2011-01-01

    The goal of the UAS integration in the NAS Project is to contribute capabili1es that reduce technical barriers related to the safety and opera1onal challenges associated with enabling routine UAS access to the NAS.

  4. Carrier spin relaxation in GaInNAsSb/GaNAsSb/GaAs quantum well

    SciTech Connect

    Asami, T.; Nosho, H.; Tackeuchi, A.; Li, L. H.; Harmand, J. C.; Lu, S. L.

    2011-12-23

    We have investigated the carrier spin relaxation in GaInNAsSb/GaNAsSb/GaAs quantum well (QW) by time-resolved photoluminescence (PL) measurement. The sample consists of an 8-nm-thick GaIn{sub 0.36}N{sub 0.006}AsSb{sub 0.015} well, 5-nm-thick GaN{sub 0.01}AsSb{sub 0.11} intermediate barriers and 100-nm-thick GaAs barriers grown by molecular beam epitaxy on a GaAs(100) substrate. The spin relaxation time and recombination lifetime at 10 K are measured to be 228 ps and 151 ps, respectively. As a reference, we have also obtained a spin relaxation time of 125 ps and a recombination lifetime of 63 ps for GaInNAs/GaNAs/GaAs QW. This result shows that crystal quality is slightly improved by adding Sb, although these short carrier lifetimes mainly originate from a nonradiative recombination. These spin relaxation times are longer than the 36 ps spin relaxation time of InGaAs/InP QWs and shorter than the 2 ns spin relaxation time of GaInNAs/GaAs QW.

  5. NAS Parallel Benchmarks. 2.4

    NASA Technical Reports Server (NTRS)

    VanderWijngaart, Rob; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    We describe a new problem size, called Class D, for the NAS Parallel Benchmarks (NPB), whose MPI source code implementation is being released as NPB 2.4. A brief rationale is given for how the new class is derived. We also describe the modifications made to the MPI (Message Passing Interface) implementation to allow the new class to be run on systems with 32-bit integers, and with moderate amounts of memory. Finally, we give the verification values for the new problem size.

  6. NAS Parallel Benchmarks, Multi-Zone Versions

    NASA Technical Reports Server (NTRS)

    vanderWijngaart, Rob F.; Haopiang, Jin

    2003-01-01

    We describe an extension of the NAS Parallel Benchmarks (NPB) suite that involves solving the application benchmarks LU, BT and SP on collections of loosely coupled discretization meshes. The solutions on the meshes are updated independently, but after each time step they exchange boundary value information. This strategy, which is common among structured-mesh production flow solver codes in use at NASA Ames and elsewhere, provides relatively easily exploitable coarse-grain parallelism between meshes. Since the individual application benchmarks also allow fine-grain parallelism themselves, this NPB extension, named NPB Multi-Zone (NPB-MZ), is a good candidate for testing hybrid and multi-level parallelization tools and strategies.

  7. Remote access for NAS: Supercomputing in a university environment

    NASA Technical Reports Server (NTRS)

    Johnson, G.; Olson, B.; Swisshelm, J.; Pryor, D.; Ziebarth, J.

    1986-01-01

    The experiment was designed to assist the Numerical Aerodynamic Simulation (NAS) Project Office in the testing and evaluation of long haul communications for remote users. The objectives of this work were to: (1) use foreign workstations to remotely access the NAS system; (2) provide NAS with a link to a large university-based computing facility which can serve as a model for a regional node of the Long-Haul Communications Subsystem (LHCS); and (3) provide a tail circuit to the University of Colorado a Boulder thereby simulating the complete communications path from NAS through a regional node to an end-user.

  8. An Implementation Plan for NFS at NASA's NAS Facility

    NASA Technical Reports Server (NTRS)

    Lam, Terance L.; Kutler, Paul (Technical Monitor)

    1998-01-01

    This document discusses how NASA's NAS can benefit from the Sun Microsystems' Network File System (NFS). A case study is presented to demonstrate the effects of NFS on the NAS supercomputing environment. Potential problems are addressed and an implementation strategy is proposed.

  9. The Need for Vendor Source Code at NAS. Revised

    NASA Technical Reports Server (NTRS)

    Carter, Russell; Acheson, Steve; Blaylock, Bruce; Brock, David; Cardo, Nick; Ciotti, Bob; Poston, Alan; Wong, Parkson; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    The Numerical Aerodynamic Simulation (NAS) Facility has a long standing practice of maintaining buildable source code for installed hardware. There are two reasons for this: NAS's designated pathfinding role, and the need to maintain a smoothly running operational capacity given the widely diversified nature of the vendor installations. NAS has a need to maintain support capabilities when vendors are not able; diagnose and remedy hardware or software problems where applicable; and to support ongoing system software development activities whether or not the relevant vendors feel support is justified. This note provides an informal history of these activities at NAS, and brings together the general principles that drive the requirement that systems integrated into the NAS environment run binaries built from source code, onsite.

  10. Factor Structure of the "Escala de Autoeficacia para la Depresion en Adolescentes" (EADA)

    ERIC Educational Resources Information Center

    Diaz-Santos, Mirella; Cumba-Aviles, Eduardo; Bernal, Guillermo; Rivera-Medina, Carmen

    2011-01-01

    The current concept and measures of self-efficacy for depression in adolescents do not consider developmental and cultural aspects essential to understand and assess this construct in Latino youth. We examined the factor structure of the "Escala de Autoeficacia para la Depresion en Adolescentes" (EADA), a Spanish instrument designed to assess this…

  11. NO3-/NO2- assimilation in halophilic archaea: physiological analysis, nasA and nasD expressions.

    PubMed

    Martínez-Espinosa, Rosa María; Lledó, Belén; Marhuenda-Egea, Frutos C; Díaz, Susana; Bonete, María José

    2009-09-01

    The haloarchaeon Haloferax mediterranei is able to assimilate nitrate or nitrite using the assimilatory nitrate pathway. An assimilatory nitrate reductase (Nas) and an assimilatory nitrite reductase (NiR) catalyze the first and second reactions, respectively. The genes involved in this process are transcribed as two messengers, one polycistronic (nasABC; nasA encodes Nas) and one monocistronic (nasD; codes for NiR). Here we report the Hfx mediterranei growth as well as the Nas and NiR activities in presence of high nitrate, nitrite and salt concentrations, using different approaches such as physiological experiments and enzymatic activities assays. The nasA and nasD expression profiles are also analysed by real-time quantitative PCR. The results presented reveal that the assimilatory nitrate/nitrite pathway in Hfx mediterranei takes place even if the salt concentration is higher than those usually present in the environments where this microorganism inhabits. This haloarchaeon grows in presence of 2 M nitrate or 50 mM nitrite, which are the highest nitrate and nitrite concentrations described from a prokaryotic microorganism. Therefore, it could be attractive for bioremediation applications in sewage plants where high salt, nitrate and nitrite concentrations are detected in wastewaters and brines. PMID:19593595

  12. Estudo de não gaussianidade nas anisotropias da RCF medidas Wmap

    NASA Astrophysics Data System (ADS)

    Andrade, A. P. A.; Wuensche, C. A.; Ribeiro, A. L. B.

    2003-08-01

    A investigação do campo de flutuações da Radiação Cósmica de Fundo (RCF) pode oferecer um importante teste para os modelos cosmológicos que descrevem a origem e a evolução das flutuações primordiais. De um lado, apresenta-se o modelo inflacionário que prevê um espectro de flutuações adiabáticas distribuídas segundo uma gaussiana e, de outro, os modelos de defeitos topológicos (dentre outros) que descrevem um mecanismo para a geração de flutuações de isocurvatura que obedecem a uma distribuição não gaussiana. Este trabalho tem como objetivo caracterizar traços do modelo não gaussiano de campo misto (entre flutuações adiabáticas e de isocurvatura) nos mapas do Wilkinson Microwave Anisotropy Probe (WMAP). Simulações das anisotropias da RCF no contexto de mistura indicam traços marcantes na distribuição das flutuações de temperatura, mesmo quando consideradas pequenas contribuições do campo de isocurvatura (da ordem de 0.001). O efeito da mistura entre os campos resulta na transferência de potência de flutuações em escalas angulares intermediárias para flutuações em pequenas escalas angulares. Este efeito pode ser caracterizado pela relação entre as amplitudes dos primeiros picos acústicos no espectro de potência da RCF. Neste trabalho, investigamos a contribuição do campo de isocurvatura, no contexto de mistura, sobre as observações recentes da RCF realizadas pelo WMAP. As previsões do modelo de campo misto, uma vez confrontadas com as observações em pequenas escalas angulares, podem ajudar a revelar a natureza das flutuações primordiais.

  13. UAS Integration in the NAS Project - FY 14 Annual Review

    NASA Technical Reports Server (NTRS)

    Grindle, Laurie; Randall, Debra; Hackenberg, Davis

    2014-01-01

    This briefing gives insight into the research activities and efforts being executed in order to integrate unmanned aircraft systems into the national airspace system. This briefing is to inform others of the UAS-NAS Projects progress and future directions.

  14. UAS Integration in the NAS FY15 Annual Review

    NASA Technical Reports Server (NTRS)

    Grindle, Laurie; Randall, Debra; Hackenburg, Davis

    2015-01-01

    This presentation gives insight into the research activities and efforts being executed in order to integrate unmanned aircraft systems into the national airspace system. This briefing is to inform others of the UAS-NAS progress and future directions.

  15. The NAS Parallel Benchmarks 2.1 Results

    NASA Technical Reports Server (NTRS)

    Saphir, William; Woo, Alex; Yarrow, Maurice

    1996-01-01

    We present performance results for version 2.1 of the NAS Parallel Benchmarks (NPB) on the following architectures: IBM SP2/66 MHz; SGI Power Challenge Array/90 MHz; Cray Research T3D; and Intel Paragon. The NAS Parallel Benchmarks are a widely-recognized suite of benchmarks originally designed to compare the performance of highly parallel computers with that of traditional supercomputers.

  16. Experimental studies on atmospheric Stirling engine NAS-2

    SciTech Connect

    Watanabe, Hiroichi; Isshiki, Naotsugu; Ohtomo, Michihiro

    1996-12-31

    Atmospheric hot air Stirling engine NAS-1 and 2 have a simple flat rubber sheet diaphragm as their power piston, and they have been experimentally studied at Nihon University for several years continuously, with the target of to get more than 100 watts shaft power by atmospheric air with simple construction and cheap material. The first NAS-1 was intended to be a solar heated engine using television glass and wood for cheap cost, but it failed by thermal break of glass, so the improved NAS-2 is changed to be heated by gas burner, using metallic materials in all parts except rubber power piston. Other than this rubber sheet diaphragm, NAS-2 has many features as using James Watt crank mechanism, high finny copper tube for conventional commercial heat exchanger, and two kinds of hot gas heaters, etc. About the rubber sheet for the power piston, the thickness of the sheet was changed from 2 mm to 6 mm gradually to known what thickness is best, and it is found that about 5 mm is best for this engine. After trying many improvements on this engine, NAS-2 has produced about 130 watt shaft power with indicated power of 350 watt at 1994. In this paper detail of many features, history, results and experiments of these NAS engines are reported.

  17. Natural attenuation software (NAS): Assessing remedial strategies and estimating timeframes

    USGS Publications Warehouse

    Mendez, E.; Widdowson, M.; Chapelle, F.; Casey, C.

    2005-01-01

    Natural Attenuation Software (NAS) is a screening tool to estimate remediation timeframes for monitored natural attenuation (MNA) and to assist in decision-making on the level of source zone treatment in conjunction with MNA using site-specific remediation objectives. Natural attenuation processes that NAS models include are advection, dispersion, sorption, non-aqueous phase liquid (NAPL) dissolution, and biodegradation of either petroleum hydrocarbons or chlorinated ethylenes. Newly-implemented enhancements to NAS designed to maximize the utility of NAS for site managers were observed. NAS has expanded source contaminant specification options to include chlorinated ethanes and chlorinated methanes, and to allow for the analysis of any other user-defined contaminants that may be subject to microbially-mediated transformations (heavy metals, radioisotopes, etc.). Included is the capability to model co-mingled plumes, with constituents from multiple contaminant categories. To enable comparison of remediation timeframe estimates between MNA and specific engineered remedial actions , NAS was modified to incorporate an estimation technique for timeframes associated with pump-and-treat remediation technology for comparison to MNA. This is an abstract of a paper presented at the 8th International In Situ and On-Site Bioremediation Symposium (Baltimore, MD 6/6-9/2005).

  18. Photoreflectance spectroscopy of step-like GaInNAs/GaInNAs/GaAs quantum wells

    NASA Astrophysics Data System (ADS)

    Kudrawiec, R.; Andrzejewski, J.; Misiewicz, J.; Gollub, D.; Forchel, A.

    2005-05-01

    Photoreflectance (PR) spectroscopy has been applied to study of step-like GaInNAs/GaInNAs/GaAs double quantum well (DQW) structures grown by molecular beam epitaxy. PR features related to optical transitions in the active part of the step-like QW structure, i.e. GaInNAs/GaInNAs QW, as well as PR features related to transitions above the step-like barrier (SLB) have been clearly observed and analysed in this paper. The analysis of the QW transitions gives information about the number of confined states in the active part of the step-like QW structure. In addition, the analysis of the second portion of PR signal gives information about the band gap energy of the SLB and optical transitions between hole and electron levels confined above the SLB.

  19. NAS - Supercomputing master tool for aeronautics. [Numerical Aerodynamic Simulation

    NASA Technical Reports Server (NTRS)

    Bailey, F. R.

    1985-01-01

    Features, performance objectives and applications planned for the NASA National Aerodynamics Simulator (NAS) are outlined. NAS was conceived in the 1970s as a means to performing numerical aerodynamic simulations beyond the scope of wind tunnel testing for high-speed flight. Present supercomputers cannot deal with problems exhibiting strongly coupled viscous effects, which are being increasingly more accurately represented by approximations to the full Navier-Stokes equations. Located at the NASA-Ames Center, the NAS will by 1990 comprise a distributed computer network capable of a 4 Gflop computing rate and have a memory capacity of 1 billion 64-bit words. Remote access to the system through UNIX-based microcomputers will be available through land lines and satellite links. New supercomputers will be tested on the system without disturbing ongoing work. The core machine will be a Cray-2 with a 2 Gflop rate.

  20. National Air Space (NAS) Data Exchange Environment Through 2060

    NASA Technical Reports Server (NTRS)

    Roy, Aloke

    2015-01-01

    NASA's NextGen Concepts and Technology Development (CTD) Project focuses on capabilities to improve safety, capacity and efficiency of the National Air Space (NAS). In order to achieve those objectives, NASA sought industry-Government partnerships to research and identify solutions for traffic flow management, dynamic airspace configuration, separation assurance, super density operations, airport surface operations and similar forward-looking air-traffic modernization (ATM) concepts. Data exchanges over NAS being the key enabler for most of these ATM concepts, the Sub-Topic area 3 of the CTD project sought to identify technology candidates that can satisfy air-to-air and air/ground communications needs of the NAS in the year 2060 timeframe. Honeywell, under a two-year contract with NASA, is working on this communications technology research initiative. This report summarizes Honeywell's research conducted during the second year of the study task.

  1. Upgrades to the Probabilistic NAS Platform Air Traffic Simulation Software

    NASA Technical Reports Server (NTRS)

    Hunter, George; Boisvert, Benjamin

    2013-01-01

    This document is the final report for the project entitled "Upgrades to the Probabilistic NAS Platform Air Traffic Simulation Software." This report consists of 17 sections which document the results of the several subtasks of this effort. The Probabilistic NAS Platform (PNP) is an air operations simulation platform developed and maintained by the Saab Sensis Corporation. The improvements made to the PNP simulation include the following: an airborne distributed separation assurance capability, a required time of arrival assignment and conformance capability, and a tactical and strategic weather avoidance capability.

  2. Phthalates and Cumulative Risk Assessment (NAS Final Report)

    EPA Science Inventory

    Risk assessment has become a dominant public policy tool for making choices, based on limited resources, to protect public health and the environment. NAS_phthalates_cover.jpg" vspace = "5" hspace="5" align="left" border="1" alt="Cover ...

  3. Advanced Intermediate-Temperature Na-S Battery

    SciTech Connect

    Lu, Xiaochuan; Kirby, Brent W.; Xu, Wu; Li, Guosheng; Kim, Jin Yong; Lemmon, John P.; Sprenkle, Vincent L.; Yang, Zhenguo

    2013-01-01

    In this study, we reported an intermediate-temperature (~150°C) sodium-sulfur (Na-S) battery. With a reduced operating temperature, this novel battery can potentially reduce the cost and safety issues associated with the conventional high-temperature (300~350°C) Na-S battery. A dense β"-Al2O3 solid membrane and tetraglyme were utilized as the electrolyte separator and catholyte solvent in this battery. Solubility tests indicated that cathode mixture of Na2S4 and S exhibited extremely high solubility in tetraglyme (e.g., > 4.1 M for Na2S4 + 4 S). CV scans of Na2S4 in tetraglyme revealed two pairs of redox couples with peaks at around 2.22 and 1.75 V, corresponding to the redox reactions of polysulfide species. The discharge/charge profiles of the Na-S battery showed a slope region and a plateau, indicating multiple steps and cell reactions. In-situ Raman measurements during battery operation suggested that polysulfide species were formed in the sequence of Na2S5 + S  Na2S5 + Na2S4 Na2S4 + Na2S2 during discharge and in a reverse order during charge. This battery showed dramatic improvement in rate capacity and cycling stability over room-temperature Na-S batteries, which makes it attractive for renewable energy integration and other grid related applications.

  4. PM MEASURES AND HUMAN EXPOSURE (NAS 1 & 2)

    EPA Science Inventory

    Under NAS research topics 1 & 2, EPA will study the mechanisms that influence the entry of fine particles into the indoor environment and to determine the emission characteristics of PM from priority indoor sources including vacuuming and combustion. Laboratory and test house st...

  5. Unstructured Adaptive (UA) NAS Parallel Benchmark. Version 1.0

    NASA Technical Reports Server (NTRS)

    Feng, Huiyu; VanderWijngaart, Rob; Biswas, Rupak; Mavriplis, Catherine

    2004-01-01

    We present a complete specification of a new benchmark for measuring the performance of modern computer systems when solving scientific problems featuring irregular, dynamic memory accesses. It complements the existing NAS Parallel Benchmark suite. The benchmark involves the solution of a stylized heat transfer problem in a cubic domain, discretized on an adaptively refined, unstructured mesh.

  6. UAS in the NAS Flight Test Series 3 Overview

    NASA Technical Reports Server (NTRS)

    Murphy, James R.

    2015-01-01

    The UAS Integration in the NAS Project is conducting a series of flight tests to acheive the following objectives: 1.) Validate results previously collected during project simulations with live data 2.) Evaluate TCAS IISS interoperability 3.) Test fully integrated system in a relevant live test environment 4.) Inform final DAA and C2 MOPS 5.) Reduce risk for Flight Test Series 4.

  7. The nasB operon and nasA gene are required for nitrate/nitrite assimilation in Bacillus subtilis.

    PubMed Central

    Ogawa, K; Akagawa, E; Yamane, K; Sun, Z W; LaCelle, M; Zuber, P; Nakano, M M

    1995-01-01

    Bacillus subtilis can use either nitrate or nitrite as a sole source of nitrogen. The isolation of the nasABCDEF genes of B. subtilis, which are required for nitrate/nitrite assimilation, is reported. The probable gene products include subunits of nitrate/nitrite reductases and an enzyme involved in the synthesis of siroheme, a cofactor for nitrite reductase. PMID:7868621

  8. Applications Performance on NAS Intel Paragon XP/S - 15#

    NASA Technical Reports Server (NTRS)

    Saini, Subhash; Simon, Horst D.; Copper, D. M. (Technical Monitor)

    1994-01-01

    The Numerical Aerodynamic Simulation (NAS) Systems Division received an Intel Touchstone Sigma prototype model Paragon XP/S- 15 in February, 1993. The i860 XP microprocessor with an integrated floating point unit and operating in dual -instruction mode gives peak performance of 75 million floating point operations (NIFLOPS) per second for 64 bit floating point arithmetic. It is used in the Paragon XP/S-15 which has been installed at NAS, NASA Ames Research Center. The NAS Paragon has 208 nodes and its peak performance is 15.6 GFLOPS. Here, we will report on early experience using the Paragon XP/S- 15. We have tested its performance using both kernels and applications of interest to NAS. We have measured the performance of BLAS 1, 2 and 3 both assembly-coded and Fortran coded on NAS Paragon XP/S- 15. Furthermore, we have investigated the performance of a single node one-dimensional FFT, a distributed two-dimensional FFT and a distributed three-dimensional FFT Finally, we measured the performance of NAS Parallel Benchmarks (NPB) on the Paragon and compare it with the performance obtained on other highly parallel machines, such as CM-5, CRAY T3D, IBM SP I, etc. In particular, we investigated the following issues, which can strongly affect the performance of the Paragon: a. Impact of the operating system: Intel currently uses as a default an operating system OSF/1 AD from the Open Software Foundation. The paging of Open Software Foundation (OSF) server at 22 MB to make more memory available for the application degrades the performance. We found that when the limit of 26 NIB per node out of 32 MB available is reached, the application is paged out of main memory using virtual memory. When the application starts paging, the performance is considerably reduced. We found that dynamic memory allocation can help applications performance under certain circumstances. b. Impact of data cache on the i860/XP: We measured the performance of the BLAS both assembly coded and Fortran coded. We found that the measured performance of assembly-coded BLAS is much less than what memory bandwidth limitation would predict. The influence of data cache on different sizes of vectors is also investigated using one-dimensional FFTs. c. Impact of processor layout: There are several different ways processors can be laid out within the two-dimensional grid of processors on the Paragon. We have used the FFT example to investigate performance differences based on processors layout.

  9. NAS Grid Benchmarks: A Tool for Grid Space Exploration

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael; VanderWijngaart, Rob F.; Biegel, Bryan (Technical Monitor)

    2001-01-01

    We present an approach for benchmarking services provided by computational Grids. It is based on the NAS Parallel Benchmarks (NPB) and is called NAS Grid Benchmark (NGB) in this paper. We present NGB as a data flow graph encapsulating an instance of an NPB code in each graph node, which communicates with other nodes by sending/receiving initialization data. These nodes may be mapped to the same or different Grid machines. Like NPB, NGB will specify several different classes (problem sizes). NGB also specifies the generic Grid services sufficient for running the bench-mark. The implementor has the freedom to choose any specific Grid environment. However, we describe a reference implementation in Java, and present some scenarios for using NGB.

  10. Evaluating the Information Power Grid using the NAS Grid Benchmarks

    NASA Technical Reports Server (NTRS)

    VanderWijngaartm Rob F.; Frumkin, Michael A.

    2004-01-01

    The NAS Grid Benchmarks (NGB) are a collection of synthetic distributed applications designed to rate the performance and functionality of computational grids. We compare several implementations of the NGB to determine programmability and efficiency of NASA's Information Power Grid (IPG), whose services are mostly based on the Globus Toolkit. We report on the overheads involved in porting existing NGB reference implementations to the IPG. No changes were made to the component tasks of the NGB can still be improved.

  11. Implementation of the NAS Parallel Benchmarks in Java

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael A.; Schultz, Matthew; Jin, Haoqiang; Yan, Jerry; Biegel, Bryan (Technical Monitor)

    2002-01-01

    Several features make Java an attractive choice for High Performance Computing (HPC). In order to gauge the applicability of Java to Computational Fluid Dynamics (CFD), we have implemented the NAS (NASA Advanced Supercomputing) Parallel Benchmarks in Java. The performance and scalability of the benchmarks point out the areas where improvement in Java compiler technology and in Java thread implementation would position Java closer to Fortran in the competition for CFD applications.

  12. Performance and Scalability of the NAS Parallel Benchmarks in Java

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael A.; Schultz, Matthew; Jin, Haoqiang; Yan, Jerry; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    Several features make Java an attractive choice for scientific applications. In order to gauge the applicability of Java to Computational Fluid Dynamics (CFD), we have implemented the NAS (NASA Advanced Supercomputing) Parallel Benchmarks in Java. The performance and scalability of the benchmarks point out the areas where improvement in Java compiler technology and in Java thread implementation would position Java closer to Fortran in the competition for scientific applications.

  13. Graded band gap GaInNAs solar cells

    SciTech Connect

    Langer, F.; Perl, S.; Kamp, M.; Höfling, S.

    2015-06-08

    Dilute nitride GaInN(Sb)As with a band gap (E{sub g}) of 1.0 eV is a promising material for the integration in next generation multijunction solar cells. We have investigated the effect of a compositionally graded GaInNAs absorber layer on the spectral response of a GaInNAs sub cell. We produced band gap gradings (ΔE{sub g}) of up to 39 meV across a 1 μm thick GaInNAs layer. Thereby, the external quantum efficiency—compared to reference cells—was increased due to the improved extraction of photo-generated carriers from 34.0% to 36.7% for the wavelength range from 900 nm to 1150 nm. However, this device figure improvement is accompanied by a small decrease in the open circuit voltage of about 20 mV and the shift of the absorption edge to shorter wavelengths.

  14. Hybrid Network Architectures for the Next Generation NAS

    NASA Technical Reports Server (NTRS)

    Madubata, Christian

    2003-01-01

    To meet the needs of the 21st Century NAS, an integrated, network-centric infrastructure is essential that is characterized by secure, high bandwidth, digital communication systems that support precision navigation capable of reducing position errors for all aircraft to within a few meters. This system will also require precision surveillance systems capable of accurately locating all aircraft, and automatically detecting any deviations from an approved path within seconds and be able to deliver high resolution weather forecasts - critical to create 4- dimensional (space and time) profiles for up to 6 hours for all atmospheric conditions affecting aviation, including wake vortices. The 21st Century NAS will be characterized by highly accurate digital data bases depicting terrain, obstacle, and airport information no matter what visibility conditions exist. This research task will be to perform a high-level requirements analysis of the applications, information and services required by the next generation National Airspace System. The investigation and analysis is expected to lead to the development and design of several national network-centric communications architectures that would be capable of supporting the Next Generation NAS.

  15. Autotasked Performance in the NAS Workload: A Statistical Analysis

    NASA Technical Reports Server (NTRS)

    Carter, R. L.; Stockdale, I. E.; Kutler, Paul (Technical Monitor)

    1998-01-01

    A statistical analysis of the workload performance of a production quality FORTRAN code for five different Cray Y-MP hardware and system software configurations is performed. The analysis was based on an experimental procedure that was designed to minimize correlations between the number of requested CPUs and the time of day the runs were initiated. Observed autotasking over heads were significantly larger for the set of jobs that requested the maximum number of CPUs. Speedups for UNICOS 6 releases show consistent wall clock speedups in the workload of around 2. which is quite good. The observed speed ups were very similar for the set of jobs that requested 8 CPUs and the set that requested 4 CPUs. The original NAS algorithm for determining charges to the user discourages autotasking in the workload. A new charging algorithm to be applied to jobs run in the NQS multitasking queues also discourages NAS users from using auto tasking. The new algorithm favors jobs requesting 8 CPUs over those that request less, although the jobs requesting 8 CPUs experienced significantly higher over head and presumably degraded system throughput. A charging algorithm is presented that has the following desirable characteristics when applied to the data: higher overhead jobs requesting 8 CPUs are penalized when compared to moderate overhead jobs requesting 4 CPUs, thereby providing a charging incentive to NAS users to use autotasking in a manner that provides them with significantly improved turnaround while also maintaining system throughput.

  16. Nitrogen regulation of nasA and the nasB operon, which encode genes required for nitrate assimilation in Bacillus subtilis.

    PubMed Central

    Nakano, M M; Yang, F; Hardin, P; Zuber, P

    1995-01-01

    The divergently transcribed nasA gene and nasB operon are required for nitrate and nitrite assimilation in Bacillus subtilis. The beta-galactosidase activity of transcriptional lacZ fusions from the nasA and nasB promoters was high when cells were grown in minimal glucose medium containing poor nitrogen sources such as nitrate, proline, or glutamate. The expression was very low when ammonium or glutamine was used as the sole nitrogen source. The repression of the genes during growth on good sources of nitrogen required wild-type glutamine synthetase (GlnA), but not GlnR, the repressor of the glnRA operon. Primer extension analysis showed that the -10 region of each promoter resembles those of sigma A-recognized promoters. Between the divergently oriented nasA and nasB promoters is a region of dyad symmetry. Mutational analysis led to the conclusion that this sequence is required in cis for the activation of both nasA and nasB. The derepression of these genes in a glnA mutant also required this sequence. These results suggest that an unidentified transcriptional activator and glutamine synthetase function in the regulation of nasA and the nasB operon. PMID:7836289

  17. Factor Analysis of the Spanish Version of the WAIS: The Escala de Inteligencia Wechsler para Adultos (EIWA).

    ERIC Educational Resources Information Center

    Gomez, Francisco C., Jr.; And Others

    1992-01-01

    The standardization of the Escala de Inteligencia Wechsler para Adultos (EIWA) and the original Wechsler Adult Intelligence Scale (WAIS) were subjected to principal components analysis to examine their comparability for 616 EIWA subjects and 800 WAIS subjects. Similarity of factor structures of both scales is supported. (SLD)

  18. Navigation in Grid Space with the NAS Grid Benchmarks

    NASA Technical Reports Server (NTRS)

    Frumkin, Michael; Hood, Robert; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    We present a navigational tool for computational grids. The navigational process is based on measuring the grid characteristics with the NAS Grid Benchmarks (NGB) and using the measurements to assign tasks of a grid application to the grid machines. The tool allows the user to explore the grid space and to navigate the execution at a grid application to minimize its turnaround time. We introduce the notion of gridscape as a user view of the grid and show how it can be me assured by NGB, Then we demonstrate how the gridscape can be used with two different schedulers to navigate a grid application through a rudimentary grid.

  19. NAS Requirements Checklist for Job Queuing/Scheduling Software

    NASA Technical Reports Server (NTRS)

    Jones, James Patton

    1996-01-01

    The increasing reliability of parallel systems and clusters of computers has resulted in these systems becoming more attractive for true production workloads. Today, the primary obstacle to production use of clusters of computers is the lack of a functional and robust Job Management System for parallel applications. This document provides a checklist of NAS requirements for job queuing and scheduling in order to make most efficient use of parallel systems and clusters for parallel applications. Future requirements are also identified to assist software vendors with design planning.

  20. Statistical Analysis of NAS Parallel Benchmarks and LINPACK Results

    NASA Technical Reports Server (NTRS)

    Meuer, Hans-Werner; Simon, Horst D.; Strohmeier, Erich; Lasinski, T. A. (Technical Monitor)

    1994-01-01

    In the last three years extensive performance data have been reported for parallel machines both based on the NAS Parallel Benchmarks, and on LINPACK. In this study we have used the reported benchmark results and performed a number of statistical experiments using factor, cluster, and regression analyses. In addition to the performance results of LINPACK and the eight NAS parallel benchmarks, we have also included peak performance of the machine, and the LINPACK n and n(sub 1/2) values. Some of the results and observations can be summarized as follows: 1) All benchmarks are strongly correlated with peak performance. 2) LINPACK and EP have each a unique signature. 3) The remaining NPB can grouped into three groups as follows: (CG and IS), (LU and SP), and (MG, FT, and BT). Hence three (or four with EP) benchmarks are sufficient to characterize the overall NPB performance. Our poster presentation will follow a standard poster format, and will present the data of our statistical analysis in detail.

  1. Concepts of Integration for UAS Operations in the NAS

    NASA Technical Reports Server (NTRS)

    Consiglio, Maria C.; Chamberlain, James P.; Munoz, Cesar A.; Hoffler, Keith D.

    2012-01-01

    One of the major challenges facing the integration of Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) is the lack of an onboard pilot that can comply with the legal requirement identified in the US Code of Federal Regulations (CFR) that pilots see and avoid other aircraft. UAS will be expected to demonstrate the means to perform the function of see and avoid while preserving the safety level of the airspace and the efficiency of the air traffic system. This paper introduces a Sense and Avoid (SAA) concept for integration of UAS into the NAS that is currently being developed by the National Aeronautics and Space Administration (NASA) and identifies areas that require additional experimental evaluation to further inform various elements of the concept. The concept design rests on interoperability principles that take into account both the Air Traffic Control (ATC) environment as well as existing systems such as the Traffic Alert and Collision Avoidance System (TCAS). Specifically, the concept addresses the determination of well clear values that are large enough to avoid issuance of TCAS corrective Resolution Advisories, undue concern by pilots of proximate aircraft and issuance of controller traffic alerts. The concept also addresses appropriate declaration times for projected losses of well clear conditions and maneuvers to regain well clear separation.

  2. High electron mobility in Ga(In)NAs films grown by molecular beam epitaxy

    SciTech Connect

    Miyashita, Naoya; Ahsan, Nazmul; Monirul Islam, Muhammad; Okada, Yoshitaka; Inagaki, Makoto; Yamaguchi, Masafumi

    2012-11-26

    We report the highest mobility values above 2000 cm{sup 2}/Vs in Si doped GaNAs film grown by molecular beam epitaxy. To understand the feature of the origin which limits the electron mobility in GaNAs, temperature dependences of mobility were measured for high mobility GaNAs and referential low mobility GaInNAs. Temperature dependent mobility for high mobility GaNAs is similar to the GaAs case, while that for low mobility GaInNAs shows large decrease in lower temperature region. The electron mobility of high quality GaNAs can be explained by intrinsic limiting factor of random alloy scattering and extrinsic factor of ionized impurity scattering.

  3. Development and Validation of the Escala de Actitudes Emprendedoras para Estudiantes (EAEE).

    PubMed

    Oliver, Amparo; Galiana, Laura

    2015-01-01

    During the last few years, entrepreneurship has gained an important role in many economic and social policies, with the consequent growth of entrepreneurial research in many social areas. However, in the Spanish psychometric context, there is not an updated scale including recent contributions to entrepreneurship attitudes literature. The aim of this study is to present and validate a new scale named Escala de Actitudes Emprendedoras para Estudiantes-EAEE, (Entrepreneurial Attitudes Scale for Students, EASS), in two samples of high school and university Spanish students. Data comes from a cross-sectional survey of 524 high school and undergraduate students, from Valencia (Spain). Two confirmatory factor analyses (CFAs) were estimated, together with reliability and validity evidence of the scale. Results offered evidence of the adequate psychometric properties of the EASS. The CFAs showed overall and analytical adequate fit indexes (? 2 (120) = 163.19 (p < .01), GFI = .906, CFI = .959, SRMR = .044, RMSEA = .040 [CI .022-.054]); reliability indices of the entrepreneurial attitudes were appropriate for most of the entrepreneurial attitudes (? were between .63 and .87 for the different dimensions); and external evidence relating entrepreneurial dimensions to personality traits was similar to in previous studies. The scale could be a useful instrument both for previous diagnosis and effectiveness assessment of programs on entrepreneurship promotion. PMID:26055696

  4. NAS Miramar Molten Carbonate Fuel Cell demonstration status

    SciTech Connect

    Scroppo, J.A.

    1996-12-31

    Part of M-C Power`s Technology Development Program, this MCFC power plant is designed to supply 250 kW of electricity to Naval Air Station (NAS) Miramar. It also cogenerates steam for the district heating system. The power plant is a fully integrated unit incorporating an advanced design fuel cell based on years of laboratory tests and a prior field test. This demonstration incorporates many innovative features, one of which is the plate type reformer which processes the natural gas fuel for use in the fuel cell. M-C Power Corp. has completed the design, fabrication, and conditioning of a 250-cell fuel cell stack, which was shipped to the site where it will be installed, tested, and evaluated as a 250 kW Proof-of-Concept MCFC Power Plant. (Originally going to Kaiser Permanente`s Sand Diego Medical Center, it was relocated to Miramar.)

  5. A Comparison of Brunt Criteria, the Non Alcoholic Fatty Liver Disease Activity Score (NAS) & a Proposed NAS-including fibrosis as Valid Diagnostic Scores for NASH

    PubMed Central

    Santiago-Rolón, Amarilys; Purcell, Dagmary; Rosado, Kathia; Toro, Doris H.

    2016-01-01

    Objective Non-alcoholic steatohepatitis (NASH) can result in cirrhosis and end stage liver disease. It is of utmost importance to differentiate NASH from simple steatosis. The aim of this study is to determine the prevalence of NASH in Latino veterans with metabolic syndrome and compare histologic grading using Brunt Criteria, the NAFLD activity score (NAS), and a proposed NAS score including fibrosis. Methods Veterans with metabolic syndrome, hepatic steatosis and elevation of ALT/AST who underwent a liver biopsy from 2004-2010 were included in this study. Biopsies were evaluated by a single blinded Hepatopathologist. Steatosis, lobular inflammation, ballooning and fibrosis were graded per specimen. Each biopsy was evaluated using Brunt criteria, NAS and NAS plus fibrosis. Results Sixty patients were included in this study, 88.3% men with a mean age of 50.4 (± 12.8). 50.0% met criteria for NASH according to the Brunt system. When classifying biopsies using NAS, only 30.0% (18/60) had a score ≥5, while when adding fibrosis, the number of patients with a score ≥5 increased to 33 (55.0%). When evaluating the predictive ability of the two scoring systems, we found that NAS including fibrosis had a higher sensitivity than NAS (86.7% vs. 40.0%) and a lower specificity (76.7% vs. 80.0%). Conclusion In our population with metabolic syndrome and altered liver function tests, about 50-55% had steatohepatitis. There were significant differences between the scoring systems. When using NAS-plus-fibrosis more patients were recognized and the sensitivity increased. Further validation studies are required to evaluate this proposed NAS scoring System. PMID:26602577

  6. Remotely Operated Aircraft (ROA) Impact on the National Airspace System (NAS) Work Package: Automation Impacts of ROA's in the NAS

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The purpose of this document is to analyze the impact of Remotely Operated Aircraft (ROA) operations on current and planned Air Traffic Control (ATC) automation systems in the En Route, Terminal, and Traffic Flow Management domains. The operational aspects of ROA flight, while similar, are not entirely identical to their manned counterparts and may not have been considered within the time-horizons of the automation tools. This analysis was performed to determine if flight characteristics of ROAs would be compatible with current and future NAS automation tools. Improvements to existing systems / processes are recommended that would give Air Traffic Controllers an indication that a particular aircraft is an ROA and modifications to IFR flight plan processing algorithms and / or designation of airspace where an ROA will be operating for long periods of time.

  7. 1.15 Å resolution structure of the proteasome-assembly chaperone Nas2 PDZ domain

    SciTech Connect

    Singh, Chingakham R.; Lovell, Scott; Mehzabeen, Nurjahan; Chowdhury, Wasimul Q.; Geanes, Eric S.; Battaile, Kevin P.; Roelofs, Jeroen

    2014-03-25

    The proteasome-assembly chaperone Nas2 binds to the proteasome subunit Rpt5 using its PDZ domain. The structure of the Nas2 PDZ domain has been determined. The 26S proteasome is a 2.5 MDa protease dedicated to the degradation of ubiquitinated proteins in eukaryotes. The assembly of this complex containing 66 polypeptides is assisted by at least nine proteasome-specific chaperones. One of these, Nas2, binds to the proteasomal AAA-ATPase subunit Rpt5. The PDZ domain of Nas2 binds to the C-terminal tail of Rpt5; however, it does not require the C-terminus of Rpt5 for binding. Here, the 1.15 Å resolution structure of the PDZ domain of Nas2 is reported. This structure will provide a basis for further insights regarding the structure and function of Nas2 in proteasome assembly.

  8. Performance Characteristics of the Multi-Zone NAS Parallel Benchmarks

    NASA Technical Reports Server (NTRS)

    Jin, Haoqiang; VanderWijngaart, Rob F.

    2003-01-01

    We describe a new suite of computational benchmarks that models applications featuring multiple levels of parallelism. Such parallelism is often available in realistic flow computations on systems of grids, but had not previously been captured in bench-marks. The new suite, named NPB Multi-Zone, is extended from the NAS Parallel Benchmarks suite, and involves solving the application benchmarks LU, BT and SP on collections of loosely coupled discretization meshes. The solutions on the meshes are updated independently, but after each time step they exchange boundary value information. This strategy provides relatively easily exploitable coarse-grain parallelism between meshes. Three reference implementations are available: one serial, one hybrid using the Message Passing Interface (MPI) and OpenMP, and another hybrid using a shared memory multi-level programming model (SMP+OpenMP). We examine the effectiveness of hybrid parallelization paradigms in these implementations on three different parallel computers. We also use an empirical formula to investigate the performance characteristics of the multi-zone benchmarks.

  9. NAS Parallel Benchmark Results 11-96. 1.0

    NASA Technical Reports Server (NTRS)

    Bailey, David H.; Bailey, David; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    The NAS Parallel Benchmarks have been developed at NASA Ames Research Center to study the performance of parallel supercomputers. The eight benchmark problems are specified in a "pencil and paper" fashion. In other words, the complete details of the problem to be solved are given in a technical document, and except for a few restrictions, benchmarkers are free to select the language constructs and implementation techniques best suited for a particular system. These results represent the best results that have been reported to us by the vendors for the specific 3 systems listed. In this report, we present new NPB (Version 1.0) performance results for the following systems: DEC Alpha Server 8400 5/440, Fujitsu VPP Series (VX, VPP300, and VPP700), HP/Convex Exemplar SPP2000, IBM RS/6000 SP P2SC node (120 MHz), NEC SX-4/32, SGI/CRAY T3E, SGI Origin200, and SGI Origin2000. We also report High Performance Fortran (HPF) based NPB results for IBM SP2 Wide Nodes, HP/Convex Exemplar SPP2000, and SGI/CRAY T3D. These results have been submitted by Applied Parallel Research (APR) and Portland Group Inc. (PGI). We also present sustained performance per dollar for Class B LU, SP and BT benchmarks.

  10. Performance Comparison of HPF and MPI Based NAS Parallel Benchmarks

    NASA Technical Reports Server (NTRS)

    Saini, Subhash

    1997-01-01

    Compilers supporting High Performance Form (HPF) features first appeared in late 1994 and early 1995 from Applied Parallel Research (APR), Digital Equipment Corporation, and The Portland Group (PGI). IBM introduced an HPF compiler for the IBM RS/6000 SP2 in April of 1996. Over the past two years, these implementations have shown steady improvement in terms of both features and performance. The performance of various hardware/ programming model (HPF and MPI) combinations will be compared, based on latest NAS Parallel Benchmark results, thus providing a cross-machine and cross-model comparison. Specifically, HPF based NPB results will be compared with MPI based NPB results to provide perspective on performance currently obtainable using HPF versus MPI or versus hand-tuned implementations such as those supplied by the hardware vendors. In addition, we would also present NPB, (Version 1.0) performance results for the following systems: DEC Alpha Server 8400 5/440, Fujitsu CAPP Series (VX, VPP300, and VPP700), HP/Convex Exemplar SPP2000, IBM RS/6000 SP P2SC node (120 MHz), NEC SX-4/32, SGI/CRAY T3E, and SGI Origin2000. We would also present sustained performance per dollar for Class B LU, SP and BT benchmarks.

  11. A Programming Model Performance Study Using the NAS Parallel Benchmarks

    DOE PAGESBeta

    Shan, Hongzhang; Blagojević, Filip; Min, Seung-Jai; Hargrove, Paul; Jin, Haoqiang; Fuerlinger, Karl; Koniges, Alice; Wright, Nicholas J.

    2010-01-01

    Harnessing the power of multicore platforms is challenging due to the additional levels of parallelism present. In this paper we use the NAS Parallel Benchmarks to study three programming models, MPI, OpenMP and PGAS to understand their performance and memory usage characteristics on current multicore architectures. To understand these characteristics we use the Integrated Performance Monitoring tool and other ways to measure communication versus computation time, as well as the fraction of the run time spent in OpenMP. The benchmarks are run on two different Cray XT5 systems and an Infiniband cluster. Our results show that in general the threemore » programming models exhibit very similar performance characteristics. In a few cases, OpenMP is significantly faster because it explicitly avoids communication. For these particular cases, we were able to re-write the UPC versions and achieve equal performance to OpenMP. Using OpenMP was also the most advantageous in terms of memory usage. Also we compare performance differences between the two Cray systems, which have quad-core and hex-core processors. We show that at scale the performance is almost always slower on the hex-core system because of increased contention for network resources.« less

  12. Spin Lifetimes in annealed GaInNAs epilayers

    NASA Astrophysics Data System (ADS)

    Tsai, Yutsung; Barman, Biplob; Scrace, Thomas; Petrou, Athos; Fukuda, Miwa; Sellers, Ian; Leroux, Mathieu; Khalfioui, Mohamed; Suny At Buffalo Collaboration; University Of Oklahoma Collaboration; Crhea-Cnrs Collaboration

    2015-03-01

    We have carried out Hanle measurements of the electron spin lifetime TSin optically pumped annealed GaInNAs epilayers (undoped and p-type doped). The samples were placed in a 7T optical magnet cryostat with the magnetic field applied in the epilayer plane. The emitted light was collected along the normal to the epilayers. The PL was excited using the 1064 nm line from a Nd:YAG laser which gives a polarization P = 5% at B =0. The transverse magnetic field results in a reduction of P, from which we determine TS. At T = 50 K, the electron spin lifetime TSwas measured to be 15 ps. As the sample temperature increases, TSdecreases (TS = 7 ps at T = 150 K). Our Hanle results are in agreement with the TSvalues measured by Lombez et al. using time-resolved photoluminescence spectroscopy. The observed sharp reduction in TSin annealed samples is interpreted as due to the D'yakonov-Perel' spin relaxation mechanism. In annealed samples the momentum relaxation time increases, resulting in a reduction of TS The authors acknowledge support through the state of Oklahoma OARs program Grant No. 12.2-040.

  13. Performance Analysis of the NAS Y-MP Workload

    NASA Technical Reports Server (NTRS)

    Bergeron, Robert J.; Kutler, Paul (Technical Monitor)

    1997-01-01

    This paper describes the performance characteristics of the computational workloads on the NAS Cray Y-MP machines, a Y-MP 832 and later a Y-MP 8128. Hardware measurements indicated that the Y-MP workload performance matured over time, ultimately sustaining an average throughput of 0.8 GFLOPS and a vector operation fraction of 87%. The measurements also revealed an operation rate exceeding 1 per clock period, a well-balanced architecture featuring a strong utilization of vector functional units, and an efficient memory organization. Introduction of the larger memory 8128 increased throughput by allowing a more efficient utilization of CPUs. Throughput also depended on the metering of the batch queues; low-idle Saturday workloads required a buffer of small jobs to prevent memory starvation of the CPU. UNICOS required about 7% of total CPU time to service the 832 workloads; this overhead decreased to 5% for the 8128 workloads. While most of the system time went to service I/O requests, efficient scheduling prevented excessive idle due to I/O wait. System measurements disclosed no obvious bottlenecks in the response of the machine and UNICOS to the workloads. In most cases, Cray-provided software tools were- quite sufficient for measuring the performance of both the machine and operating, system.

  14. Structures of genes nasA and nasB, encoding assimilatory nitrate and nitrite reductases in Klebsiella pneumoniae M5al.

    PubMed Central

    Lin, J T; Goldman, B S; Stewart, V

    1993-01-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources during aerobic growth. Assimilatory nitrate and nitrite reductases convert nitrate through nitrite to ammonium. We report here the molecular cloning of the nasA and nasB genes, which encode assimilatory nitrate and nitrite reductase, respectively. These genes are tightly linked and probably form a nasBA operon. In vivo protein expression and DNA sequence analysis revealed that the nasA and nasB genes encode 92- and 104-kDa proteins, respectively. The NASA polypeptide is homologous to other prokaryotic molybdoenzymes, and the NASB polypeptide is homologous to eukaryotic and prokaryotic NADH-nitrite reductases. The narL gene product positively regulates expression of the structural genes for respiratory nitrate reductase, narGHJI. Surprisingly, we found that the nasBA operon is tightly linked to the narL-narGHJI region in K. pneumoniae, even though the nitrate assimilatory and respiratory enzymes serve different physiological functions. Images PMID:8468296

  15. 48 CFR 852.236-83 - Payments under fixed-price construction contracts (including NAS).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... prescribed in 832.111, insert the following clause in contracts that contain a section entitled “Network...) Failure either to meet schedules in Section Network Analysis System (NAS), or to process the Interim Arrow... of Section Network Analysis System (NAS) to the contracting officer for approval within 90...

  16. Looking Backward: Parting Reflections on Higher Education Reform from NAS's Founding President

    ERIC Educational Resources Information Center

    Balch, Stephen H.

    2012-01-01

    Twenty-five years at the helm of the National Association of Scholars (NAS) have left the author with vivid memories: of knocks and bruises, peaks of exhilaration and, especially, unforgettable characters. But as for lessons learned, that's a very different story. In this article, the author shares some of the successes that happened in NAS for…

  17. 48 CFR 852.236-83 - Payments under fixed-price construction contracts (including NAS).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... prescribed in 832.111, insert the following clause in contracts that contain a section entitled “Network...) Failure either to meet schedules in Section Network Analysis System (NAS), or to process the Interim Arrow... of Section Network Analysis System (NAS) to the contracting officer for approval within 90...

  18. Natural Attenuation Software (NAS): A computer program for estimating remediation times of contaminated groundwater

    USGS Publications Warehouse

    Mendez, E.; Widdowson, M.; Brauner, S.; Chapelle, F.; Casey, C.

    2004-01-01

    This paper describes the development and application of a modeling system called Natural Attenuation Software (NAS). NAS was designed as a screening tool to estimate times of remediation (TORs), associated with monitored natural attenuation (MNA), to lower groundwater contaminant concentrations to regulatory limits. Natural attenuation processes that NAS models include advection, dispersion, sorption, biodegradation, and non-aqueous phase liquid (NAPL) dissolution. This paper discusses the three main interactive components of NAS: 1) estimation of the target source concentration required for a plume extent to contract to regulatory limits, 2) estimation of the time required for NAFL contaminants in the source area to attenuate to a predetermined target source concentration, and 3) estimation of the time required for a plume extent to contract to regulatory limits after source reduction. The model's capability is illustrated by results from a case study at a MNA site, where NAS time of remediation estimates compared well with observed monitoring data over multiple years.

  19. Determination of composition of non-homogeneous GaInNAs layers

    NASA Astrophysics Data System (ADS)

    Pucicki, D.; Bielak, K.; Ściana, B.; Radziewicz, D.; Latkowska-Baranowska, M.; Kováč, J.; Vincze, A.; Tłaczała, M.

    2016-01-01

    Dilute nitride GaInNAs alloys grown on GaAs have become perspective materials for so called low-cost GaAs-based devices working within the optical wavelength range up to 1.6 μm. The multilayer structures of GaInNAs/GaAs multi-quantum well (MQW) samples usually are analyzed by using high resolution X-ray diffraction (HRXRD) measurements. However, demands for precise structural characterization of the GaInNAs containing heterostructures requires taking into consideration all inhomogeneities of such structures. This paper describes some of the material challenges and progress in structural characterization of GaInNAs layers. A new algorithm for structural characterization of dilute nitrides which bounds contactless electro-reflectance (CER) or photo-reflectance (PR) measurements and HRXRD analysis results together with GaInNAs quantum well band diagram calculation is presented. The triple quantum well (3QW) GaInNAs/GaAs structures grown by atmospheric-pressure metalorganic vapor-phase epitaxy (AP-MOVPE) were investigated according to the proposed algorithm. Thanks to presented algorithm, more precise structural data including the nonuniformity in the growth direction of GaInNAs/GaAs QWs were achieved. Therefore, the proposed algorithm is mentioned as a nondestructive method for characterization of multicomponent inhomogeneous semiconductor structures with quantum wells.

  20. Computational Aeroscience at NAS and Future Trends in High Performance Computing

    NASA Technical Reports Server (NTRS)

    Cooper, David M.

    1994-01-01

    NASA's Numerical Aerodynamic Simulation (NAS) program provides a unique world class supercomputing capability which is readily accessed by the U.S. aeronautics community and offers them the opportunity to perform high speed computations and simulations for a broad range of aerospace research applications. In addition, the NAS program performs on-going research and advanced technology development to ensure the innovative application of newly emerging technologies to computational fluid dynamics and other important aeroscience disciplines. The NAS system and its interaction with industry are described. Furthermore, the results of an analysis of current and future technologies and their potential impact on high performance computing are also presented.

  1. Testing New Programming Paradigms with NAS Parallel Benchmarks

    NASA Technical Reports Server (NTRS)

    Jin, H.; Frumkin, M.; Schultz, M.; Yan, J.

    2000-01-01

    Over the past decade, high performance computing has evolved rapidly, not only in hardware architectures but also with increasing complexity of real applications. Technologies have been developing to aim at scaling up to thousands of processors on both distributed and shared memory systems. Development of parallel programs on these computers is always a challenging task. Today, writing parallel programs with message passing (e.g. MPI) is the most popular way of achieving scalability and high performance. However, writing message passing programs is difficult and error prone. Recent years new effort has been made in defining new parallel programming paradigms. The best examples are: HPF (based on data parallelism) and OpenMP (based on shared memory parallelism). Both provide simple and clear extensions to sequential programs, thus greatly simplify the tedious tasks encountered in writing message passing programs. HPF is independent of memory hierarchy, however, due to the immaturity of compiler technology its performance is still questionable. Although use of parallel compiler directives is not new, OpenMP offers a portable solution in the shared-memory domain. Another important development involves the tremendous progress in the internet and its associated technology. Although still in its infancy, Java promisses portability in a heterogeneous environment and offers possibility to "compile once and run anywhere." In light of testing these new technologies, we implemented new parallel versions of the NAS Parallel Benchmarks (NPBs) with HPF and OpenMP directives, and extended the work with Java and Java-threads. The purpose of this study is to examine the effectiveness of alternative programming paradigms. NPBs consist of five kernels and three simulated applications that mimic the computation and data movement of large scale computational fluid dynamics (CFD) applications. We started with the serial version included in NPB2.3. Optimization of memory and cache usage was applied to several benchmarks, noticeably BT and SP, resulting in better sequential performance. In order to overcome the lack of an HPF performance model and guide the development of the HPF codes, we employed an empirical performance model for several primitives found in the benchmarks. We encountered a few limitations of HPF, such as lack of supporting the "REDISTRIBUTION" directive and no easy way to handle irregular computation. The parallelization with OpenMP directives was done at the outer-most loop level to achieve the largest granularity. The performance of six HPF and OpenMP benchmarks is compared with their MPI counterparts for the Class-A problem size in the figure in next page. These results were obtained on an SGI Origin2000 (195MHz) with MIPSpro-f77 compiler 7.2.1 for OpenMP and MPI codes and PGI pghpf-2.4.3 compiler with MPI interface for HPF programs.

  2. A Method for Suppressing Line Overload Phenomena Using NAS Battery Systems

    NASA Astrophysics Data System (ADS)

    Ohtaka, Toshiya; Iwamoto, Shinichi

    In this paper, we pay attention to the superior operating control function and instantaneous discharging characteristics of NAS battery systems, and propose a method for determining installation planning and operating control schemes of NAS battery systems for suppressing line overload phenomena. In the stage of planning, a target contingency is identified, and an optimal allocation and capacity of NAS battery systems and an amount of generation changes are determined for the contingency. In the stage of operation, the control strategy of NAS battery system is determined. Simulations are carried out for verifying the validity of the proposed method using the IEEJ 1 machine V system model and an example 2 machine 16 bus system model.

  3. The influence of nitrogen and antimony on the optical quality of InNAs(Sb) alloys

    NASA Astrophysics Data System (ADS)

    Latkowska, M.; Baranowski, M.; Linhart, W. M.; Janiaka, F.; Misiewicz, J.; Segercrantz, N.; Tuomisto, F.; Zhuang, Q.; Krier, A.; Kudrawiec, R.

    2016-03-01

    In this work we present detailed studies of the influence of nitrogen and antimony on the optical quality of InNAs(Sb) alloys. We employed photoluminescence, photoreflectance and positron annihilation spectroscopy to reveal the role of antimony and nitrogen on the improvement/degradation of the optical qualities of InNAs(Sb) alloys. A series of 1 μm-thick InNAs(Sb) layers with different nitrogen and antimony concentrations were grown by molecular beam epitaxy. The results of these investigations show that Sb atoms serve as a surfactant which effectively improves the optical quality of InNAsSb alloys. The influence of nitrogen on the optical quality however is not the same as to what has been reported for other dilute nitrides. We observed an improvement of the optical quality for some nitrogen contents. These issues are comprehensively examined and explained.

  4. Shadow Mode Assessment Using Realistic Technologies for the National Airspace (SMART NAS)

    NASA Technical Reports Server (NTRS)

    Kopardekar, Parimal H.

    2014-01-01

    Develop a simulation and modeling capability that includes: (a) Assessment of multiple parallel universes, (b) Accepts data feeds, (c) Allows for live virtual constructive distribute environment, (d) Enables integrated examinations of concepts, algorithms, technologies and National Airspace System (NAS) architectures.

  5. Low temperature grown GaNAsSb: A promising material for photoconductive switch application

    SciTech Connect

    Tan, K. H.; Yoon, S. F.; Wicaksono, S.; Loke, W. K.; Li, D. S.; Saadsaoud, N.; Tripon-Canseliet, C.; Lampin, J. F.; Decoster, D.; Chazelas, J.

    2013-09-09

    We report a photoconductive switch using low temperature grown GaNAsSb as the active material. The GaNAsSb layer was grown at 200 °C by molecular beam epitaxy in conjunction with a radio frequency plasma-assisted nitrogen source and a valved antimony cracker source. The low temperature growth of the GaNAsSb layer increased the dark resistivity of the switch and shortened the carrier lifetime. The switch exhibited a dark resistivity of 10{sup 7} Ω cm, a photo-absorption of up to 2.1 μm, and a carrier lifetime of ∼1.3 ps. These results strongly support the suitability of low temperature grown GaNAsSb in the photoconductive switch application.

  6. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project Subcommittee Final

    NASA Technical Reports Server (NTRS)

    Johnson, Chuck; Griner, James H.; Hayhurst, Kelly J.; Shively, Robert J.; Consiglio, Maria; Muller, Eric; Murphy, James; Kim, Sam

    2012-01-01

    UAS Integration in the NAS Project overview with details from each of the subprojects. Subprojects include: Communications, Certification, Integrated Test and Evaluation, Human Systems Integration, and Separation Assurance/Sense and Avoid Interoperability.

  7. Performance assessment of multijunction solar cells incorporating GaInNAsSb

    PubMed Central

    2014-01-01

    We have measured the characteristics of molecular beam epitaxy grown GaInNAsSb solar cells with different bandgaps using AM1.5G real sun illumination. Based on the solar cell diode characteristics and known parameters for state-of-the-art GaInP/GaAs and GaInP/GaAs/Ge cells, we have calculated the realistic potential efficiency increase for GaInP/GaAs/GaInNAsSb and GaInP/GaAs/GaInNAsSb/Ge multijunction solar cells for different current matching conditions. The analyses reveal that realistic GaInNAsSb solar cell parameters, render possible an extraction efficiency of over 36% at 1-sun AM1.5D illumination. PACS 88.40.hj; 88.40.jm; 88.40.jp; 81.15.Hi PMID:24498981

  8. 78 FR 12951 - TRICARE; Elimination of the Non-Availability Statement (NAS) Requirement for Non-Emergency...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-26

    ... (NAS) Requirement for Non-Emergency Inpatient Mental Health Care AGENCY: Office of the Secretary... NAS is needed for non-emergency inpatient mental health care in order for a TRICARE Standard beneficiary's claim to be paid. Currently, NAS are required for non-emergency inpatient mental health care...

  9. GaInNAs Junctions for Next-Generation Concentrators: Progress and Prospects

    SciTech Connect

    Friedman, D. J.; Ptak, A. J.; Kurtz, S. R.; Geisz, J. F.; Kiehl, J.

    2005-08-01

    We discuss progress in the development of GaInNAs junctions for application in next-generation multijunction concentrator cells. A significant development is the demonstration of near-100% internal quantum efficiencies in junctions grown by molecular-beam epitaxy. Testing at high currents validates the compatibility of these devices with concentrator operation. The efficiencies of several next-generation multijunction structures incorporating these state-of-the-art GaInNAs junctions are projected.

  10. The NAS Alert System: a look at the first eight years

    USGS Publications Warehouse

    Fuller, Pam L.; Neilson, Matt; Huge, Dane H.

    2013-01-01

    The U.S. Geological Survey's Nonindigenous Aquatic Species (NAS) database program (http://nas.er.usgs.gov) tracks the distribution of introduced aquatic organisms across the United States. Awareness of, and timely response to, novel species introductions by those involved in nonindigenous aquatic species management and research requires a framework for rapid dissemination of occurrence data as it is incorporated into the NAS database. In May 2004, the NAS program developed an alert system to notify registered users of new introductions as part of a national early detection/rapid response system. This article summarizes information on system users and dispatched alerts from the system's inception through the end of 2011. The NAS alert system has registered over 1,700 users, with approximately 800 current subscribers. A total of 1,189 alerts had been transmitted through 2011. More alerts were sent for Florida (134 alerts) than for any other state. Fishes comprise the largest taxonomic group of alerts (440), with mollusks, plants, and crustaceans each containing over 100 alerts. Most alerts were for organisms that were intentionally released (414 alerts), with shipping, escape from captivity, and hitchhiking also representing major vectors. To explore the archive of sent alerts and to register, the search and signup page for the alert system can be found online at http://nas.er.usgs.gov/AlertSystem/default.aspx.

  11. Dilute-As AlNAs Alloy for Deep-Ultraviolet Emitter.

    PubMed

    Tan, Chee-Keong; Borovac, Damir; Sun, Wei; Tansu, Nelson

    2016-01-01

    The band structures of dilute-As AlNAs alloys with As composition ranging from 0% up to 12.5% are studied by using First-Principle Density Functional Theory (DFT) calculation. The energy band gap shows remarkable reduction from 6.19 eV to 3.87 eV with small amount of As content in the AlNAs alloy, which covers the deep ultraviolet (UV) spectral regime. A giant bowing parameter of 30.5 eV ± 0.5 eV for AlNAs alloy is obtained. In addition, our analysis shows that the crossover between crystal field split-off (CH) band and heavy hole (HH) bands occurs in the dilute-As AlNAs alloy with As-content of ~1.5%. This result implies the possibility of dominant transverse electric (TE)-polarized emission by using AlNAs alloy with dilute amount of As-content. Our findings indicate the potential of dilute-As AlNAs alloy as the new active region material for TE-polarized III-Nitride-based deep UV light emitters. PMID:26905060

  12. Hydrazine N Source for Growth of GaInNAs for Solar Cells

    SciTech Connect

    Friedman, D. J.; Geisz, G. F.; Kurtz, S. R.; Norman, A. G.; Yeh, Y. C. M.

    1999-05-25

    We evaluate hydrazine (Hy) as a nitrogen precursor source for the growth of GaNAs and GaInNAs for application in 1-eV solar cells lattice-matched to GaAs, and compare it to the more commonly used dimethylhydrazine (DMHy). The incorporation efficiency of N into the GaNAs alloy is found to be one to two orders of magnitude higher with Hy than with DMHy. This high N incorporation makes convenient the growth of GaNAs at higher growth temperatures, Tg=650 C, and arsine flows, AsH3/III=44, than are generally possible with the use of DMHy. GaInNAs and GaNAs solar cells are grown under these growth conditions and compared to a GaAs cell grown under the same conditions to determine the extent to which the poor minority-carrier properties routinely observed for the N-containing material can be attributed to the growth conditions. Finally, the background carrier concentrations for Hy- and DMHy-grown material are compared, and little difference is found between the two sources..

  13. Dilute-As AlNAs Alloy for Deep-Ultraviolet Emitter

    PubMed Central

    Tan, Chee-Keong; Borovac, Damir; Sun, Wei; Tansu, Nelson

    2016-01-01

    The band structures of dilute-As AlNAs alloys with As composition ranging from 0% up to 12.5% are studied by using First-Principle Density Functional Theory (DFT) calculation. The energy band gap shows remarkable reduction from 6.19 eV to 3.87 eV with small amount of As content in the AlNAs alloy, which covers the deep ultraviolet (UV) spectral regime. A giant bowing parameter of 30.5 eV ± 0.5 eV for AlNAs alloy is obtained. In addition, our analysis shows that the crossover between crystal field split-off (CH) band and heavy hole (HH) bands occurs in the dilute-As AlNAs alloy with As-content of ~1.5%. This result implies the possibility of dominant transverse electric (TE)-polarized emission by using AlNAs alloy with dilute amount of As-content. Our findings indicate the potential of dilute-As AlNAs alloy as the new active region material for TE-polarized III-Nitride-based deep UV light emitters. PMID:26905060

  14. Comparison of Scores on the WAIS and Its Puerto Rican Counterpart, Escala de Inteligencia Wechsler para Adultos, in an Institutionalized Latin American Psychiatric Population.

    ERIC Educational Resources Information Center

    Davis, Todd McLin; Rodriguez, Vene L.

    1979-01-01

    Compared vocabulary and block design subtests of the Wechsler Adult Intelligence Scale (WAIS) and its Puerto Rican counterpart, the Escala de Inteligencia Wechsler para Adultos (EIWA), in hospitalized Latins and Trans-Caribbean Blacks. EIWA scores were significantly higher than WAIS scores. Equivalence of EIWA and WAIS estimates is questioned.…

  15. Comparison of Scores on the WAIS and Its Puerto Rican Counterpart, Escala de Inteligencia Wechsler para Adultos, in an Institutionalized Latin American Psychiatric Population.

    ERIC Educational Resources Information Center

    Davis, Todd McLin; Rodriguez, Vene L.

    1979-01-01

    Compared vocabulary and block design subtests of the Wechsler Adult Intelligence Scale (WAIS) and its Puerto Rican counterpart, the Escala de Inteligencia Wechsler para Adultos (EIWA), in hospitalized Latins and Trans-Caribbean Blacks. EIWA scores were significantly higher than WAIS scores. Equivalence of EIWA and WAIS estimates is questioned.…

  16. First-principles study on structure stabilities of ?-S and Na-S battery systems

    NASA Astrophysics Data System (ADS)

    Momida, Hiroyoshi; Oguchi, Tamio

    2014-03-01

    To understand microscopic mechanisms of charge and discharge reactions in Na-S batteries, there has been increasing needs to study fundamental atomic and electronic structures of elemental S as well as that of Na-S phases. The most stable form of S is known to be an orthorhombic ?-S crystal at ambient temperature and pressure, and ?-S consists of puckered S8 rings which crystallize in space group Fddd . In this study, the crystal structure of ?-S is examined by using first-principles calculations with and without the van der Waals interaction corrections of Grimme's method, and results clearly show that the van der Waals interactions between the S8 rings have crucial roles on cohesion of ?-S. We also study structure stabilities of Na2S, NaS, NaS2, and Na2S5 phases with reported crystal structures. Using calculated total energies of the crystal structure models, we estimate discharge voltages assuming discharge reactions from 2Na+ xS -->Na2Sx, and discharge reactions in Na/S battery systems are discussed by comparing with experimental results. This work was partially supported by Elements Strategy Initiative for Catalysts and Batteries (ESICB) of Ministry of Education, Culture, Sports, Science, and Technology (MEXT), Japan.

  17. UAS in the NAS: Survey Responses by ATC, Manned Aircraft Pilots, and UAS Pilots

    NASA Technical Reports Server (NTRS)

    Comstock, James R., Jr.; McAdaragh, Raymon; Ghatas, Rania W.; Burdette, Daniel W.; Trujillo, Anna C.

    2014-01-01

    NASA currently is working with industry and the Federal Aviation Administration (FAA) to establish future requirements for Unmanned Aircraft Systems (UAS) flying in the National Airspace System (NAS). To work these issues NASA has established a multi-center "UAS Integration in the NAS" project. In order to establish Ground Control Station requirements for UAS, the perspective of each of the major players in NAS operations was desired. Three on-line surveys were administered that focused on Air Traffic Controllers (ATC), pilots of manned aircraft, and pilots of UAS. Follow-up telephone interviews were conducted with some survey respondents. The survey questions addressed UAS control, navigation, and communications from the perspective of small and large unmanned aircraft. Questions also addressed issues of UAS equipage, especially with regard to sense and avoid capabilities. From the civilian ATC and military ATC perspectives, of particular interest are how mixed operations (manned / UAS) have worked in the past and the role of aircraft equipage. Knowledge gained from this information is expected to assist the NASA UAS Integration in the NAS project in directing research foci thus assisting the FAA in the development of rules, regulations, and policies related to UAS in the NAS.

  18. UAS in the NAS: Survey Responses by ATC, Manned Aircraft Pilots, and UAS Pilots

    NASA Technical Reports Server (NTRS)

    Comstock, James R., Jr.; McAdaragh, Raymon; Ghatas, Rania W.; Burdette, Daniel W.; Trujillo, Anna C.

    2013-01-01

    NASA currently is working with industry and the Federal Aviation Administration (FAA) to establish future requirements for Unmanned Aircraft Systems (UAS) flying in the National Airspace System (NAS). To work these issues NASA has established a multi-center UAS Integration in the NAS project. In order to establish Ground Control Station requirements for UAS, the perspective of each of the major players in NAS operations was desired. Three on-line surveys were administered that focused on Air Traffic Controllers (ATC), pilots of manned aircraft, and pilots of UAS. Follow-up telephone interviews were conducted with some survey respondents. The survey questions addressed UAS control, navigation, and communications from the perspective of small and large unmanned aircraft. Questions also addressed issues of UAS equipage, especially with regard to sense and avoid capabilities. From the ATC and military ATC perspective, of particular interest is how mixed-operations (manned/UAS) have worked in the past and the role of aircraft equipage. Knowledge gained from this information is expected to assist the NASA UAS in the NAS project in directing research foci thus assisting the FAA in the development of rules, regulations, and policies related to UAS in the NAS.

  19. Six Years of Parallel Computing at NAS (1987 - 1993): What Have we Learned?

    NASA Technical Reports Server (NTRS)

    Simon, Horst D.; Cooper, D. M. (Technical Monitor)

    1994-01-01

    In the fall of 1987 the age of parallelism at NAS began with the installation of a 32K processor CM-2 from Thinking Machines. In 1987 this was described as an "experiment" in parallel processing. In the six years since, NAS acquired a series of parallel machines, and conducted an active research and development effort focused on the use of highly parallel machines for applications in the computational aerosciences. In this time period parallel processing for scientific applications evolved from a fringe research topic into the one of main activities at NAS. In this presentation I will review the history of parallel computing at NAS in the context of the major progress, which has been made in the field in general. I will attempt to summarize the lessons we have learned so far, and the contributions NAS has made to the state of the art. Based on these insights I will comment on the current state of parallel computing (including the HPCC effort) and try to predict some trends for the next six years.

  20. The NAS Perchlorate Review: Questions Remain about the Perchlorate RfD

    PubMed Central

    Ginsberg, Gary; Rice, Deborah

    2005-01-01

    Human exposure to perchlorate is commonplace because it is a contaminant of drinking water, certain foods, and breast milk. The U.S. Environmental Protection Agency (EPA) conducted a perchlorate risk assessment in 2002 that yielded a reference dose (RfD) based on both the animal and human toxicology data. This assessment has been superceded by a recent National Academy of Science (NAS) review that derived a perchlorate RfD that is 20-fold greater (less stringent) than that derived by the U.S. EPA in 2002. The NAS-derived RfD was put on the U.S. EPA’s Integrated Risk Information System (IRIS) database very quickly and with no further public review. In this commentary we raise concerns about the NAS approach to RfD development in three areas of toxicity assessment: the dose that the NAS described as a no observable adverse-effect level is actually associated with perchlorate-induced effects; consideration of uncertainties was insufficient; and the NAS considered the inhibition of iodine uptake to be a nonadverse effect. We conclude that risk assessors should carefully evaluate whether the IRIS RfD is the most appropriate value for assessing perchlorate risk. PMID:16140613

  1. Improved performance in GaInNAs solar cells by hydrogen passivation

    SciTech Connect

    Fukuda, M.; Whiteside, V. R.; Keay, J. C.; Meleco, A.; Sellers, I. R.; Hossain, K.; Golding, T. D.; Leroux, M.; Al Khalfioui, M.

    2015-04-06

    The effect of UV-activated hydrogenation on the performance of GaInNAs solar cells is presented. A proof-of-principle investigation was performed on non-optimum GaInNAs cells, which allowed a clearer investigation of the role of passivation on the intrinsic nitrogen-related defects in these materials. Upon optimized hydrogenation of GaInNAs, a significant reduction in the presence of defect and impurity based luminescence is observed as compared to that of unpassivated reference material. This improvement in the optical properties is directly transferred to an improved performance in solar cell operation, with a more than two-fold improvement in the external quantum efficiency and short circuit current density upon hydrogenation. Temperature dependent photovoltaic measurements indicate a strong contribution of carrier localization and detrapping processes, with non-radiative processes dominating in the reference materials, and evidence for additional strong radiative losses in the hydrogenated solar cells.

  2. GaNAsP: An intermediate band semiconductor grown by gas-source molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Kuang, Y. J.; Yu, K. M.; Kudrawiec, R.; Luce, A. V.; Ting, M.; Walukiewicz, W.; Tu, C. W.

    2013-03-01

    Dilute nitride GaNAsP thin films were grown via a GaAsP metamorphic buffer on GaP(100) substrate with gas-source molecular beam epitaxy. The compositions of this III-V-V-V compound were determined by channeling Rutherford backscattering spectroscopy and nuclear reaction analysis. Photoreflectance shows two distinctive transitions from the valence band to the split conduction bands due to N incorporation. Photoluminescence and optical absorption show the fundamental bandgap of Ga(N)AsP is largely tailored by the small amount of N. The observed multiband characteristics and the bandgap tunability of GaNAsP are two merits that fit into the intermediate-band solar cell roadmap, and GaNAsP of high crystal quality provides a strong candidate for intermediate band solar cell materials.

  3. Optical properties of GaNAs and GaInAsN quantum wells

    NASA Astrophysics Data System (ADS)

    Potter, R. J.; Balkan, N.

    2004-08-01

    We present an overview of our optical characterization work on dilute nitride quantum well (QW) samples. A simple model for calculating interband transition energies is constructed, tested against published \\bi {k}\\bdot \\bi {p} results and used to model experimental data. Steady state photoluminescence (PL), time-resolved PL and photomodulated reflectance measurements are utilized to characterize GaNAs/GaAs, GaInNAs/GaAs and InGaAs/GaAs QWs. The effects of carrier localization, hot-carrier relaxation, non-radiative recombination and the reduced bandgap temperature dependence of dilute nitrides are investigated. Emission from recombining hot carriers in a GaInNAs/GaAs QW is recorded and used to estimate the LO-phonon scattering energy. The addition of small fractions of N is found to have little effect on phonon energy, which is found to be \\hbar \\omega =29.7 meV.

  4. An Evaluation of the NaS Battery Storage Potential for Providing Regulation Service in California

    SciTech Connect

    Lu, Ning; Weimar, Mark R.; Makarov, Yuri V.; Loutan, Clyde

    2011-03-23

    Sodium sulfur (NaS) batteries can provide energy storage, real-time dispatch, regulation, frequency response, and other essential services to the power grids. This study presents the technical characteristics, modeling approach, methodologies, and results for providing regulation services in the California Independent System Operator (CAISO) market. Two different scenarios were studied and compared: a scenario without intermittent renewable-energy resource penetration (base case) and a scenario with significant renewable-energy resource penetration (including wind) reaching 20% of CAISO’s energy supply. In addition, breakeven cost analyses were developed for four cases. Based on the results of the technical and cost analyses, the opportunities for the NaS battery providing the regulation services are discussed, design improvements for the battery’s physical characteristics are recommended, and modifications of the regulation signals sent to NaS batteries are proposed.

  5. Examination of Frameworks for Safe Integration of Intelligent Small UAS into the NAS

    NASA Technical Reports Server (NTRS)

    Logan, Michael J.

    2012-01-01

    This paper discusses a proposed framework for the safe integration of small unmanned aerial systems (sUAS) into the National Airspace System (NAS). The paper briefly examines the potential uses of sUAS to build an understanding of the location and frequency of potential future flight operations based on the future applications of the sUAS systems. The paper then examines the types of systems that would be required to meet the application-level demand to determine "classes" of platforms and operations. A framework for categorization of the "intelligence" level of the UAS is postulated for purposes of NAS integration. Finally, constraints on the intelligent systems are postulated to ensure their ease of integration into the NAS.

  6. Molecular beam epitaxy grown GaNAsSb 1 eV photovoltaic cell

    NASA Astrophysics Data System (ADS)

    Tan, K. H.; Wicaksono, S.; Loke, W. K.; Li, D.; Yoon, S. F.; Fitzgerald, E. A.; Ringel, S. A.; Harris, J. S., Jr.

    2011-11-01

    We report the performance of a 1 eV GaNAsSb-based photovoltaic cell grown using a molecular beam epitaxy system equipped with a radio frequency (RF) plasma-assisted nitrogen source. The 1 ?m-thick photoabsorption layer contains 2% of N and 6% of Sb resulting in a GaNAsSb layer with bandgap energy of 1.0 eV. Under AM1.5G solar illumination condition with and without 850 nm long pass filter, the GaNAsSb-based photovoltaic cell demonstrates a JSC values of 15 and 32 mA/W, respectively. Deep level transient spectroscopy analysis reveals that the VOC of the photovoltaic cell could possibly be limited by the presence of arsenic antisite defects.

  7. Compositional dependence of the band gap in Ga(NAsP) quantum well heterostructures

    NASA Astrophysics Data System (ADS)

    Jandieri, K.; Ludewig, P.; Wegele, T.; Beyer, A.; Kunert, B.; Springer, P.; Baranovskii, S. D.; Koch, S. W.; Volz, K.; Stolz, W.

    2015-08-01

    We present experimental and theoretical studies of the composition dependence of the direct band gap energy in Ga(NAsP)/GaP quantum well heterostructures grown on either (001) GaP- or Si-substrates. The theoretical description takes into account the band anti-crossing model for the conduction band as well as the modification of the valence subband structure due to the strain resulting from the pseudomorphic epitaxial growth on the respective substrate. The composition dependence of the direct band gap of Ga(NAsP) is obtained for a wide range of nitrogen and phosphorus contents relevant for laser applications on Si-substrate.

  8. The role of specialized processors in the NAS program - Retrospective/prospective

    NASA Technical Reports Server (NTRS)

    Levin, Eugene; Preston, Frank

    1988-01-01

    The Numerical Aerodynamic Simulation (NAS) Program was initiated by NASA to establish a national resource for scientific research and engineering applications of computational fluid dynamics. This paper examines the changing views of the roles of general purpose and special purpose processors in this program in response to changes in technology as well as changes in perceived needs. The time period covered extends from more than 10 years ago, through the present, and concludes with some speculative concepts for the future roles of specialized processors in the advanced NAS system.

  9. Unintentional Calcium Incorporation in Ga(Al, In, N)As

    SciTech Connect

    Hurst, J. B.; Lewis, S. D.; Oye, M. M.; Homes, A. L., Jr.; Ptak, A. J.; Reedy, R. C.

    2007-05-01

    Unintentional calcium incorporation into GaInNAs causes an acceptor-type impurity, which limits the ability of {approx}1 eV GaInNAs-based solar cells to collect photogenerated current. Here, the authors focus on better understanding the conditions by which Ca is incorporated into GaInNAs. Various material combinations were grown including GaAs, InGaAs, GaInNAs, and Al(Ga)As. The materials were primarily grown by solid-source molecular-beam epitaxy (MBE) at {approx}400 and 580--620 C, with comparisons made to metal-organic chemical vapor deposition (MOCVD)-grown materials where appropriate. Calcium incorporation was measured through secondary ion mass spectrometry. There was no measurable Ca incorporation into MBE-grown GaAs at 580 C, but Ca incorporates into GaAs at low MBE growth temperatures ({approx}400 C) that are comparable to those typically used for GaInNAs. This suggests that the N species is not solely responsible for the observed Ca incorporation into MBE-grown GaInNAs; but rather, defects associated with the low temperature growth may also be a factor. The effects of defect-related Ca incorporation were further studied at interfaces between Al(Ga)As and GaAs, and substrates pretreated with an O2 plasma and NH4OH etch. Ca incorporation was observed at the interface between Al0.3Ga0.7As/GaAs, AlAs/GaAs, and at the epilayer/substrate interface for the pretreated samples. No Ca was observed in InGaAs samples grown by either MBE or MOCVD, suggesting the Ca incorporation into GaInNAs has something to do with the addition of nitrogen. Therefore, the authors propose that the likely causes of Ca incorporation into GaInNAs are a Ca--N affinity, defects generated by low temperature growth, defects generated by the incorporation of N into GaAs, or some combination thereof.

  10. Composition modulation in GaInNAs quantum wells: Comparison of experiment and theory

    NASA Astrophysics Data System (ADS)

    Herrera, M.; González, D.; Hopkinson, M.; Gutiérrez, M.; Navaretti, P.; Liu, H. Y.; García, R.

    2005-04-01

    Composition modulation observed in GaInNAs quantum wells imposes an important handicap to their potential application within optical components, particularly as the indium and nitrogen contents are increased to reach longer wavelengths. In this paper, we compare our experimental results of phase separation in GaInNAs quantum wells grown at different temperatures with recent theoretical models of spinodal decomposition from the literature. This comparison has shown that the regular solution approximation, which explains the higher composition modulation compared to GaInAs samples, provides a more appropriate explanation of GaInNAs decomposition than the usual delta lattice-parameter approximation. Transmission electron microscopy shows no composition modulation contrasts with the chemical sensitive 002 dark field reflection and a strong increase in the intensity of the strain contrasts observed with 220 bright field reflection as the growth temperature increases from 360to460°C. These observations can be explained by an uncoupling between N and In composition profiles forming separate In-rich and N-rich regions according to the regular solution approximation model. We therefore believe that the compositional fluctuations in GaInNAs are not only due to GaInAs decomposition, but that an uncoupled modulation of the III and V elements is also present.

  11. Beyond the NAS Parallel Benchmarks: Measuring Dynamic Program Performance and Grid Computing Applications

    NASA Technical Reports Server (NTRS)

    VanderWijngaart, Rob F.; Biswas, Rupak; Frumkin, Michael; Feng, Huiyu; Biegel, Bryan (Technical Monitor)

    2001-01-01

    The contents include: 1) A brief history of NPB; 2) What is (not) being measured by NPB; 3) Irregular dynamic applications (UA Benchmark); and 4) Wide area distributed computing (NAS Grid Benchmarks-NGB). This paper is presented in viewgraph form.

  12. Comparison of Origin 2000 and Origin 3000 Using NAS Parallel Benchmarks

    NASA Technical Reports Server (NTRS)

    Turney, Raymond D.

    2001-01-01

    This report describes results of benchmark tests on the Origin 3000 system currently being installed at the NASA Ames National Advanced Supercomputing facility. This machine will ultimately contain 1024 R14K processors. The first part of the system, installed in November, 2000 and named mendel, is an Origin 3000 with 128 R12K processors. For comparison purposes, the tests were also run on lomax, an Origin 2000 with R12K processors. The BT, LU, and SP application benchmarks in the NAS Parallel Benchmark Suite and the kernel benchmark FT were chosen to determine system performance and measure the impact of changes on the machine as it evolves. Having been written to measure performance on Computational Fluid Dynamics applications, these benchmarks are assumed appropriate to represent the NAS workload. Since the NAS runs both message passing (MPI) and shared-memory, compiler directive type codes, both MPI and OpenMP versions of the benchmarks were used. The MPI versions used were the latest official release of the NAS Parallel Benchmarks, version 2.3. The OpenMP versiqns used were PBN3b2, a beta version that is in the process of being released. NPB 2.3 and PBN 3b2 are technically different benchmarks, and NPB results are not directly comparable to PBN results.

  13. 48 CFR 852.236-83 - Payments under fixed-price construction contracts (including NAS).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... waste and trash) 5 Sewage treatment plant equipment 5 Water treatment plant equipment 5 Washers (dish, cage, glass, etc.) 5 Sterilizing equipment 5 Water distilling equipment 5 Prefab temperature rooms...) Failure either to meet schedules in Section Network Analysis System (NAS), or to process the Interim...

  14. UAS Integration in the NAS Project: Integrated Test and LVC Infrastructure

    NASA Technical Reports Server (NTRS)

    Murphy, Jim; Hoang, Ty

    2015-01-01

    Overview presentation of the Integrated Test and Evaluation sub-project of the Unmanned Aircraft System (UAS) in the National Airspace System (NAS). The emphasis of the presentation is the Live, Virtual, and Constructive (LVC) system (a broadly used name for classifying modeling and simulation) infrastructure and use of external assets and connection.

  15. 48 CFR 852.236-82 - Payments under fixed-price construction contracts (without NAS).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Payments under fixed-price construction contracts (without NAS). 852.236-82 Section 852.236-82 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses...

  16. 48 CFR 852.236-83 - Payments under fixed-price construction contracts (including NAS).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Payments under fixed-price construction contracts (including NAS). 852.236-83 Section 852.236-83 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses...

  17. 48 CFR 852.236-82 - Payments under fixed-price construction contracts (without NAS).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... “Network Analysis System (NAS).” Payments Under Fixed-Price Construction Contracts (APR 1984) The clause... 5 Water treatment plant equipment 5 Washers (dish, cage, glass, etc.) 5 Sterilizing equipment 5 Water distilling equipment 5 Prefab temperature rooms (cold, constant temperature) 5 Entire...

  18. UAS-NAS Integrated Human in the Loop: Test Environment Report

    NASA Technical Reports Server (NTRS)

    Murphy, Jim; Otto, Neil; Jovic, Srba

    2015-01-01

    The desire and ability to fly Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) is of increasing urgency. The application of unmanned aircraft to perform national security, defense, scientific, and emergency management are driving the critical need for less restrictive access by UAS to the NAS. UAS represent a new capability that will provide a variety of services in the government (public) and commercial (civil) aviation sectors. The growth of this potential industry has not yet been realized due to the lack of a common understanding of what is required to safely operate UAS in the NAS. NASA's UAS Integration in the NAS Project is conducting research in the areas of Separation Assurance/Sense and Avoid Interoperability (SSI), Human Systems Integration (HSI), and Communication to support reducing the barriers of UAS access to the NAS. This research was broken into two research themes namely, UAS Integration and Test Infrastructure. UAS Integration focuses on airspace integration procedures and performance standards to enable UAS integration in the air transportation system, covering Sense and Avoid (SAA) performance standards, command and control performance standards, and human systems integration. The focus of the Test Infrastructure theme was to enable development and validation of airspace integration procedures and performance standards, including the execution of integrated test and evaluation. In support of the integrated test and evaluation efforts, the Project developed an adaptable, scalable, and schedulable relevant test environment incorporating live, virtual, and constructive elements capable of validating concepts and technologies for unmanned aircraft systems to safely operate in the NAS. To accomplish this task, the Project planned to conduct three integrated events: a Human-in-the-Loop simulation and two Flight Test series that integrated key concepts, technologies and/or procedures in a relevant air traffic environment. Each of the integrated events were built on the technical achievements, fidelity and complexity of previous simulations and tests, resulting in research findings that support the development of regulations governing the access of UAS into the NAS. The purpose of this document is to describe how well the system under test was representative

  19. 76 FR 57690 - TRICARE; Elimination of the Non-Availability Statement (NAS) Requirement for Non-Emergency...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-16

    ... (NAS) Requirement for Non-Emergency Inpatient Mental Health Care AGENCY: Office of the Secretary... states a NAS is needed for non-emergency inpatient mental health care in order for a TRICARE Standard... the MTF catchment area for non-emergency inpatient mental health care. Currently, the number of...

  20. Meeting of Experts on NASA's Unmanned Aircraft System (UAS) Integration in the National Airspace Systems (NAS) Project

    NASA Technical Reports Server (NTRS)

    Wolfe, Jean; Bauer, Jeff; Bixby, C.J.; Lauderdale, Todd; Shively, Jay; Griner, James; Hayhurst, Kelly

    2010-01-01

    Topics discussed include: Aeronautics Research Mission Directorate Integrated Systems Research Program (ISRP) and UAS Integration in the NAS Project; UAS Integration into the NAS Project; Separation Assurance and Collision Avoidance; Pilot Aircraft Interface Objectives/Rationale; Communication; Certification; and Integrated Tests and Evaluations.

  1. 75 FR 28610 - Draft EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-21

    ... AGENCY Draft EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments... Issues Related to Dioxin Toxicity and Response to NAS Comments'' (EPA/600/R- 10/038A). This draft report... 2,3,7,8-tetrachlorodibenzo-p- dioxin (TCDD). These analyses have not been in previous versions...

  2. Ubiquity and diversity of heterotrophic bacterial nasA genes in diverse marine environments.

    PubMed

    Jiang, Xuexia; Dang, Hongyue; Jiao, Nianzhi

    2015-01-01

    Nitrate uptake by heterotrophic bacteria plays an important role in marine N cycling. However, few studies have investigated the diversity of environmental nitrate assimilating bacteria (NAB). In this study, the diversity and biogeographical distribution of NAB in several global oceans and particularly in the western Pacific marginal seas were investigated using both cultivation and culture-independent molecular approaches. Phylogenetic analyses based on 16S rRNA and nasA (encoding the large subunit of the assimilatory nitrate reductase) gene sequences indicated that the cultivable NAB in South China Sea belonged to the α-Proteobacteria, γ-Proteobacteria and CFB (Cytophaga-Flavobacteria-Bacteroides) bacterial groups. In all the environmental samples of the present study, α-Proteobacteria, γ-Proteobacteria and Bacteroidetes were found to be the dominant nasA-harboring bacteria. Almost all of the α-Proteobacteria OTUs were classified into three Roseobacter-like groups (I to III). Clone library analysis revealed previously underestimated nasA diversity; e.g. the nasA gene sequences affiliated with β-Proteobacteria, ε-Proteobacteria and Lentisphaerae were observed in the field investigation for the first time, to the best of our knowledge. The geographical and vertical distributions of seawater nasA-harboring bacteria indicated that NAB were highly diverse and ubiquitously distributed in the studied marginal seas and world oceans. Niche adaptation and separation and/or limited dispersal might mediate the NAB composition and community structure in different water bodies. In the shallow-water Kueishantao hydrothermal vent environment, chemolithoautotrophic sulfur-oxidizing bacteria were the primary NAB, indicating a unique nitrate-assimilating community in this extreme environment. In the coastal water of the East China Sea, the relative abundance of Alteromonas and Roseobacter-like nasA gene sequences responded closely to algal blooms, indicating that NAB may be active participants contributing to the bloom dynamics. Our statistical results suggested that salinity, temperature and nitrate may be some of the key environmental factors controlling the composition and dynamics of the marine NAB communities. PMID:25647610

  3. Ubiquity and Diversity of Heterotrophic Bacterial nasA Genes in Diverse Marine Environments

    PubMed Central

    Jiang, Xuexia; Dang, Hongyue; Jiao, Nianzhi

    2015-01-01

    Nitrate uptake by heterotrophic bacteria plays an important role in marine N cycling. However, few studies have investigated the diversity of environmental nitrate assimilating bacteria (NAB). In this study, the diversity and biogeographical distribution of NAB in several global oceans and particularly in the western Pacific marginal seas were investigated using both cultivation and culture-independent molecular approaches. Phylogenetic analyses based on 16S rRNA and nasA (encoding the large subunit of the assimilatory nitrate reductase) gene sequences indicated that the cultivable NAB in South China Sea belonged to the α-Proteobacteria, γ-Proteobacteria and CFB (Cytophaga-Flavobacteria-Bacteroides) bacterial groups. In all the environmental samples of the present study, α-Proteobacteria, γ-Proteobacteria and Bacteroidetes were found to be the dominant nasA-harboring bacteria. Almost all of the α-Proteobacteria OTUs were classified into three Roseobacter-like groups (I to III). Clone library analysis revealed previously underestimated nasA diversity; e.g. the nasA gene sequences affiliated with β-Proteobacteria, ε-Proteobacteria and Lentisphaerae were observed in the field investigation for the first time, to the best of our knowledge. The geographical and vertical distributions of seawater nasA-harboring bacteria indicated that NAB were highly diverse and ubiquitously distributed in the studied marginal seas and world oceans. Niche adaptation and separation and/or limited dispersal might mediate the NAB composition and community structure in different water bodies. In the shallow-water Kueishantao hydrothermal vent environment, chemolithoautotrophic sulfur-oxidizing bacteria were the primary NAB, indicating a unique nitrate-assimilating community in this extreme environment. In the coastal water of the East China Sea, the relative abundance of Alteromonas and Roseobacter-like nasA gene sequences responded closely to algal blooms, indicating that NAB may be active participants contributing to the bloom dynamics. Our statistical results suggested that salinity, temperature and nitrate may be some of the key environmental factors controlling the composition and dynamics of the marine NAB communities. PMID:25647610

  4. Defect study of molecular beam epitaxy grown undoped GaInNAsSb thin film using junction-capacitance spectroscopy

    SciTech Connect

    Monirul Islam, Muhammad; Miyashita, Naoya; Ahsan, Nazmul; Okada, Yoshitaka

    2013-02-18

    Defects in undoped GaInNAsSb thin film (i-GaInNAsSb) were investigated by junction-capacitance technique using admittance and transient photocapacitance (TPC) spectroscopy. An electron trap D2 was identified at 0.34 eV below the conduction band (E{sub C}) of i-GaInNAsSb using admittance spectroscopy. Optical transition of valance band (E{sub V}) electrons to a localized state OH1 (E{sub V} + 0.75 eV) was manifested in negative TPC signal. Combined activation energy of OH1 and D2 defect corresponds to the band-gap of i-GaInNAsSb, suggesting that OH1/D2 acts as an efficient recombination center. TPC signal at {approx}1.59 eV above E{sub V} was attributed to the nitrogen-induced localized state in GaInNAsSb.

  5. NAS technical summaries. Numerical aerodynamic simulation program, March 1992 - February 1993

    NASA Technical Reports Server (NTRS)

    1994-01-01

    NASA created the Numerical Aerodynamic Simulation (NAS) Program in 1987 to focus resources on solving critical problems in aeroscience and related disciplines by utilizing the power of the most advanced supercomputers available. The NAS Program provides scientists with the necessary computing power to solve today's most demanding computational fluid dynamics problems and serves as a pathfinder in integrating leading-edge supercomputing technologies, thus benefitting other supercomputer centers in government and industry. The 1992-93 operational year concluded with 399 high-speed processor projects and 91 parallel projects representing NASA, the Department of Defense, other government agencies, private industry, and universities. This document provides a glimpse at some of the significant scientific results for the year.

  6. Object-Oriented Implementation of the NAS Parallel Benchmarks using Charm++

    NASA Technical Reports Server (NTRS)

    Krishnan, Sanjeev; Bhandarkar, Milind; Kale, Laxmikant V.

    1996-01-01

    This report describes experiences with implementing the NAS Computational Fluid Dynamics benchmarks using a parallel object-oriented language, Charm++. Our main objective in implementing the NAS CFD kernel benchmarks was to develop a code that could be used to easily experiment with different domain decomposition strategies and dynamic load balancing. We also wished to leverage the object-orientation provided by the Charm++ parallel object-oriented language, to develop reusable abstractions that would simplify the process of developing parallel applications. We first describe the Charm++ parallel programming model and the parallel object array abstraction, then go into detail about each of the Scalar Pentadiagonal (SP) and Lower/Upper Triangular (LU) benchmarks, along with performance results. Finally we conclude with an evaluation of the methodology used.

  7. GlnR positively regulates nasA transcription in Streptomyces coelicolor.

    PubMed

    Wang, Jin; Zhao, Guo-Ping

    2009-08-14

    The model actinomycete, Streptomyces coelicolor is able to grow with nitrate as the sole nitrogen source. In this study, an assimilatory nitrate reductase encoding gene, nasA (SCO2473) was, for the first time, identified from the genome of S. coelicolor by genetic and physiological means. We also proved that GlnR, a previously characterized global nitrogen regulator in S. coelicolor, positively regulated the transcription of nasA via specific binding to a cis-element similar but different from the previously characterized consensus sequence. This finding will certainly facilitate the better understanding about both the functional scope and the mechanism of action of GlnR in regulating nitrogen metabolism in S. coelicolor. PMID:19501565

  8. Moth eye antireflection coated GaInP/GaAs/GaInNAs solar cell

    NASA Astrophysics Data System (ADS)

    Aho, Arto; Tommila, Juha; Tukiainen, Antti; Polojärvi, Ville; Niemi, Tapio; Guina, Mircea

    2014-09-01

    The performance of a GaInP/GaAs/GaInNAs solar cell incorporating AlInP moth eye antireflection coating is reported and compared with the performance of a similar cell comprising TiO2/SiO2 antireflection coating. The moth eye coating exhibits an average reflectance of only 2% within the spectral range from 400 nm to 1600 nm. EQE measurements revealed absorption-related losses in the AlInP moth eye coating at wavelengths below 510 nm. Short wavelength absorption decreases the current generation in the top GaInP junction by 10%. Despite the absorption losses, the moth eye patterned GaInP/GaAs/GaInNAs solar cell exhibited higher current generation under AM1.5G real sun illumination.

  9. The temperature dependence of atomic incorporation characteristics in growing GaInNAs films

    SciTech Connect

    Li, Jingling; Gao, Fangliang; Wen, Lei; Zhou, Shizhong; Zhang, Shuguang E-mail: msgli@scut.edu.cn; Li, Guoqiang E-mail: msgli@scut.edu.cn

    2015-02-07

    We have systematically studied the temperature dependence of incorporation characteristics of nitrogen (N) and indium (In) in growing GaInNAs films. With the implementation of Monte-Carlo simulation, the low N adsorption energy (−0.10 eV) is demonstrated. To understand the atomic incorporation mechanism, temperature dependence of interactions between Group-III and V elements are subsequently discussed. We find that the In incorporation behaviors rather than that of N are more sensitive to the T{sub g}, which can be experimentally verified by exploring the compositional modulation and structural changes of the GaInNAs films by means of high-resolution X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope, and secondary ion mass spectroscopy.

  10. Enhanced-Depletion-Width GaInNAs Solar Cells Grown by Molecular-Beam Epitaxy

    SciTech Connect

    Ptak, A. J.; Friedman, D. J.

    2005-01-01

    The 3-junction, GaInP2/GaAs/Ge solar cell is a non-optimized structure due to excess light falling on the Ge junction. Because of this, a fourth junction inserted between the GaAs and Ge subcells could use the excess light and provide an increase in device efficiency. Unfortunately, the leading candidate material, GaInNAs, suffers from very low minority-carrier diffusion lengths compared to its parent compound, GaAs. These low diffusion lengths do not allow for the collection of adequate current to keep the overall 4-junction structure current matched. If the currents generated from the GaInNAs subcell are increased, the possibility exists for practical efficiencies of greater than 40% from this structure.

  11. NAS Parallel Benchmarks I/O Version 2.4. 2.4

    NASA Technical Reports Server (NTRS)

    Wong, Parkson; VanderWijngaart, Rob F.; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    We describe a benchmark problem, based on the Block-Tridiagonal (BT) problem of the NAS Parallel Benchmarks (NPB), which is used to test the output capabilities of high-performance computing systems, especially parallel systems. We also present a source code implementation of the benchmark, called NPBIO2.4-MPI, based on the MPI implementation of NPB, using a variety of ways to write the computed solutions to file.

  12. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project

    NASA Technical Reports Server (NTRS)

    Griner, James H.

    2013-01-01

    NASA's UAS Integration in the NAS project, has partnered with Rockwell Collins to develop a concept Control and Non-Payload Communication system prototype radio, operating on recently allocated UAS frequency spectrum bands. The prototype radio will be used to validate initial proposed performance requirements for UAS control communications. This presentation will give an overview of the current status of the design, development, and flight test planning for this prototype radio.

  13. Functional Requirements Document for HALE UAS Operations in the NAS: Step 1. Version 3

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The purpose of this Functional Requirements Document (FRD) is to compile the functional requirements needed to achieve the Access 5 Vision of "operating High Altitude, Long Endurance (HALE) Unmanned Aircraft Systems (UAS) routinely, safely, and reliably in the national airspace system (NAS)" for Step 1. These functional requirements could support the development of a minimum set of policies, procedures and standards by the Federal Aviation Administration (FAA) and various standards organizations. It is envisioned that this comprehensive body of work will enable the FAA to establish and approve regulations to govern safe operation of UAS in the NAS on a routine or daily "file and fly" basis. The approach used to derive the functional requirements found within this FRD was to decompose the operational requirements and objectives identified within the Access 5 Concept of Operations (CONOPS) into the functions needed to routinely and safely operate a HALE UAS in the NAS. As a result, four major functional areas evolved to enable routine and safe UAS operations for an on-demand basis in the NAS. These four major functions are: Aviate, Navigate, Communicate, and Avoid Hazards. All of the functional requirements within this document can be directly traceable to one of these four major functions. Some functions, however, are traceable to several, or even all, of these four major functions. These cross-cutting functional requirements support the "Command / Control: function as well as the "Manage Contingencies" function. The requirements associated to these high-level functions and all of their supporting low-level functions are addressed in subsequent sections of this document.

  14. Large-scale structural analysis: The structural analyst, the CSM Testbed and the NAS System

    NASA Technical Reports Server (NTRS)

    Knight, Norman F., Jr.; Mccleary, Susan L.; Macy, Steven C.; Aminpour, Mohammad A.

    1989-01-01

    The Computational Structural Mechanics (CSM) activity is developing advanced structural analysis and computational methods that exploit high-performance computers. Methods are developed in the framework of the CSM testbed software system and applied to representative complex structural analysis problems from the aerospace industry. An overview of the CSM testbed methods development environment is presented and some numerical methods developed on a CRAY-2 are described. Selected application studies performed on the NAS CRAY-2 are also summarized.

  15. Carrier trapping and escape times in p-i-n GaInNAs MQW structures

    PubMed Central

    2014-01-01

    We used a semi-classical model to describe carrier capture into and thermionic escape from GaInNAs/GaAs multiple quantum wells (MQWs) situated within the intrinsic region of a GaAs p-i-n junction. The results are used to explain photocurrent oscillations with applied bias observed in these structures, in terms of charge accumulation and resonance tunnelling. PMID:24417767

  16. NAS technical summaries: Numerical aerodynamic simulation program, March 1991 - February 1992

    NASA Technical Reports Server (NTRS)

    1992-01-01

    NASA created the Numerical Aerodynamic Simulation (NAS) Program in 1987 to focus resources on solving critical problems in aeroscience and related disciplines by utilizing the power of the most advanced supercomputers available. The NAS Program provides scientists with the necessary computing power to solve today's most demanding computational fluid dynamics problems and serves as a pathfinder in integrating leading-edge supercomputing technologies, thus benefiting other supercomputer centers in Government and industry. This report contains selected scientific results from the 1991-92 NAS Operational Year, March 4, 1991 to March 3, 1992, which is the fifth year of operation. During this year, the scientific community was given access to a Cray-2 and a Cray Y-MP. The Cray-2, the first generation supercomputer, has four processors, 256 megawords of central memory, and a total sustained speed of 250 million floating point operations per second. The Cray Y-MP, the second generation supercomputer, has eight processors and a total sustained speed of one billion floating point operations per second. Additional memory was installed this year, doubling capacity from 128 to 256 megawords of solid-state storage-device memory. Because of its higher performance, the Cray Y-MP delivered approximately 77 percent of the total number of supercomputer hours used during this year.

  17. Determination of composition and energy gaps of GaInNAsSb layers grown by MBE

    NASA Astrophysics Data System (ADS)

    Aho, A.; Korpijärvi, V.-M.; Isoaho, R.; Malinen, P.; Tukiainen, A.; Honkanen, M.; Guina, M.

    2016-03-01

    We present a method to accurately determine the composition of GaInNAsSb heterostructures and a modified band anti-crossing model to calculate the corresponding bandgaps. The composition determination method is based on combining x-ray diffractometry and energy dispersive x-ray spectroscopy measurements. The modified band anti-crossing model was derived from the model known for GaInNAs and using band-gap composition relations for GaInAs, GaInSb, InAsSb and GaAsSb. The model parameters were defined by fitting with experimental bandgap data retrieved from photoluminescence. For validation and data fitting we used experimental samples with N composition in the range of 0-0.06, In composition from 0 to 0.17, and Sb composition in the range of 0-0.08. All samples were thermally annealed to minimize the band gap shift caused by the short range ordering effects in GaInNAsSb crystal. The modified model yields an excellent fit to the experimental band gap data with an accuracy of ~20 meV, and is a practical tool for designing, fabricating and analyzing optoelectronics devices.

  18. Effects of Bismuth on Wide-Depletion-Width GaInNAs Solar Cells

    SciTech Connect

    Ptak, A. J.; France, R.; Jiang, C.-S.; Reedy, R. C.

    2008-05-01

    GaInNAs solar cells could be useful in next-generation multijunction solar cells if issues surrounding low photocurrents and photovoltages are surmounted. Wide-depletion-width devices generate significant photocurrent using a p-i-n structure grown by molecular beam epitaxy, but these depletion widths are only realized in a region of parameter space that leads to rough surface morphologies. Here, bismuth is explored as a surfactant for the growth of GaInNAs solar cells. Very low fluxes of Bi are effective at maintaining smooth surfaces, even at high growth temperatures and In contents. However, Bi also increases the net donor concentration in these materials, manifested in our n-on-p device structures as a pn-junction that moves deeper into the base layer with increasing Bi fluxes. Quantum efficiency modeling and scanning kelvin probe microscopy measurements confirm the type conversion of the base layer from p type to n type. Bi incorporation in GaAsBi samples shows signs of surface segregation, leading to a finite buildup time, and this effect may lead to slow changes in the electrical properties of the GaInNAs(Bi) devices. Bi also appears to create a defect level, although this defect level is not deleterious enough to increase the dark current in the devices.

  19. Structural properties of GaNAs nanowires probed by micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Filippov, S.; Ishikawa, F.; Chen, W. M.; Buyanova, I. A.

    2016-02-01

    GaNAs-based nanowires (NWs) form a novel material system of potential importance for applications in advanced optoelectronic and photonic devices, thanks to the advantages provided by band-structure engineering, one-dimensional architecture and the possibility to combine them with mainstream silicon technology. In this work we utilize the micro-Raman scattering technique to systematically study the structural properties of such GaAs/GaNAs core/shell NW structures grown by molecular beam epitaxy on a Si substrate. It is shown that the employed one-dimensional architecture allows the fabrication of a GaNAs shell with a low degree of alloy disorder and weak residual strain, at least within the studied range of nitrogen (N) compositions [N] < 0.6%. Raman scattering by the GaAs-like and GaN-like phonons is found to be enhanced when the excitation energy approaches the E+ transition energy. Since this effect is found to be more pronounced for the GaN-like phonons, the involved intermediate states are concluded to be localized in proximity to N impurities, i.e. they likely represent N-related cluster states located in proximity to E+.

  20. Selective Defects Passivation of GaInNAs Solar Cells by Hydrogenation

    NASA Astrophysics Data System (ADS)

    Fukuda, Miwa; Whiteside, Vincent R.; Sellers, Ian R.; Al Khalfioui, Mohamed; Leroux, Mathieu; Phinney, Lucas; Hossain, Khalid

    2014-03-01

    While GaInNAs has the potential to be a fourth-junction in multi-junction solar cells it has proved difficult to achieve the optimal alloy composition due to the low solubility of nitrogen in these materials. At this point we investigate the possibility of improving the performance of GaInNAs using hydrogenation to selectively passivate mid-gap defects, while preserving the functionality of substitutional nitrogen. Temperature dependent photoluminescence measurements of the intrinsic region of a GaInNAs p-i-n solar cell show a classic ``s-shape'' associated with localization prior to hydrogenation, while after hydrogenation no sign of the ``s-shape'' is evident. The preliminary investigations of the effect of hydrogenation on the efficiency of carrier transport in the solar cells will also be presented. Amethyst Research Inc.'s photon-assisted defect mitigation-hydrogenation technique is usually a low temperature process; however, the annealing effects will be de-convoluted from that of hydrogenation. Research supported by Amethyst Research Inc. through the state of Oklahoma, OARS 12.2-040 program.

  1. Improved performance due to selective passivation of nitrogen clusters in GaInNAs solar cells

    NASA Astrophysics Data System (ADS)

    Fukuda, Miwa; Whiteside, Vincent R.; Al Khalfioui, Mohamed; Leroux, Mathieu; Hossain, Khalid; Sellers, Ian R.

    2015-03-01

    While GaInNAs has the potential to be a fourth-junction in multi-junction solar cells it has proved to be difficult to incorporate due to the low solubility of nitrogen in these materials. Specifically, mid-gap states attributed to nitrogen clusters have proved prohibitive for practical implementation of these systems. Here, we present the selective passivation of nitrogen impurities using a UV-activated hydrogenation process, which enables the removal of defects while retaining substitution nitrogen. Temperature dependent photoluminescence measurements of the intrinsic region of a GaInNAs p-i-n solar cell show a classic ``s-shape'' associated with localization prior to hydrogenation, while after hydrogenation no sign of the ``s-shape'' is evident. This passivation of nitrogen centers is reflected in improved performance of solar cells structures relative to reference, unpassivated devices presenting a potential route to practical implementation of GaInNAs solar cells. The authors acknowledge support through Oklahoma Center for the Advancement of Science and Technology under the Oklahoma Applied Research Support Grant No. AR12.2-040.

  2. First-principle natural band alignment of GaN / dilute-As GaNAs alloy

    NASA Astrophysics Data System (ADS)

    Tan, Chee-Keong; Tansu, Nelson

    2015-01-01

    Density functional theory (DFT) calculations with the local density approximation (LDA) functional are employed to investigate the band alignment of dilute-As GaNAs alloys with respect to the GaN alloy. Conduction and valence band positions of dilute-As GaNAs alloy with respect to the GaN alloy on an absolute energy scale are determined from the combination of bulk and surface DFT calculations. The resulting GaN / GaNAs conduction to valence band offset ratio is found as approximately 5:95. Our theoretical finding is in good agreement with experimental observation, indicating the upward movements of valence band at low-As content dilute-As GaNAs are mainly responsible for the drastic reduction of the GaN energy band gap. In addition, type-I band alignment of GaN / GaNAs is suggested as a reasonable approach for future device implementation with dilute-As GaNAs quantum well, and possible type-II quantum well active region can be formed by using InGaN / dilute-As GaNAs heterostructure.

  3. First-principle natural band alignment of GaN / dilute-As GaNAs alloy

    SciTech Connect

    Tan, Chee-Keong Tansu, Nelson

    2015-01-15

    Density functional theory (DFT) calculations with the local density approximation (LDA) functional are employed to investigate the band alignment of dilute-As GaNAs alloys with respect to the GaN alloy. Conduction and valence band positions of dilute-As GaNAs alloy with respect to the GaN alloy on an absolute energy scale are determined from the combination of bulk and surface DFT calculations. The resulting GaN / GaNAs conduction to valence band offset ratio is found as approximately 5:95. Our theoretical finding is in good agreement with experimental observation, indicating the upward movements of valence band at low-As content dilute-As GaNAs are mainly responsible for the drastic reduction of the GaN energy band gap. In addition, type-I band alignment of GaN / GaNAs is suggested as a reasonable approach for future device implementation with dilute-As GaNAs quantum well, and possible type-II quantum well active region can be formed by using InGaN / dilute-As GaNAs heterostructure.

  4. Desarrollo de la Escala sobre el Estigma Relacionado con el VIH/SIDA para Profesionales de la Salud mediante el uso de métodos mixtos123

    PubMed Central

    Varas-Díaz, Nelson; Neilands, Torsten B.; Guilamo-Ramos, Vincent; Cintrón Bou, Francheska N.

    2009-01-01

    El estigma relacionado con el VIH/SIDA continúa siendo un obstáculo para la prevención primaria y secundaria del VIH. Las consecuencias para las personas que viven con la enfermedad han sido muy documentadas y continúan siendo una gran preocupación para las personas que proveen servicios de salud y para aquellas que investigan el tema. Estas consecuencias son preocupantes cuando el estigma emana de profesionales de la salud porque se puede limitar el acceso a los servicios. Uno de los principales obstáculos para la investigación del estigma relacionado con el VIH en Puerto Rico es la falta de instrumentos cuantitativos para evaluar las manifestaciones del estigma entre profesionales de la salud. El objetivo principal de este estudio fue desarrollar y probar las propiedades psicométricas de una escala sobre el estigma relacionado con el VIH/SIDA culturalmente apropiada para personas que proveen servicios de salud puertorriqueñas y desarrollar una versión corta de la escala que pudiera usarse en escenarios clínicos con tiempo limitado. El instrumento desarrollado estuvo basado en evidencia cualitativa recopilada entre profesionales y estudiantes de profesiones de la salud puertorriqueños/as (n=80) y administrado a una muestra de 421 profesionales de la salud en adiestramiento. La escala contenía 12 dimensiones del estigma relacionado con el VIH/SIDA. El análisis cuantitativo corroboró 11 de ellas, teniendo como resultado un instrumento con validez y confiabilidad satisfactoria. Estas dimensiones, a su vez, fueron subcomponentes de un factor de estigma general superior. PMID:20333258

  5. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project. NASA Contributions to the SARP WC Definition

    NASA Technical Reports Server (NTRS)

    Randall, Debra K.; Consiglio, Maria Cristina; Santiago, Confesor

    2014-01-01

    To better inform sense and avoid research needs and to understand ongoing investigation of potential solutions that ultimately lead to the assisting the FAA with their Congressional mandate to fly UAS in the NAS.

  6. Effect of antimony on the deep-level traps in GaInNAsSb thin films

    SciTech Connect

    Islam, Muhammad Monirul Miyashita, Naoya; Ahsan, Nazmul; Okada, Yoshitaka; Sakurai, Takeaki; Akimoto, Katsuhiro

    2014-09-15

    Admittance spectroscopy has been performed to investigate the effect of antimony (Sb) on GaInNAs material in relation to the deep-level defects in this material. Two electron traps, E1 and E2 at an energy level 0.12 and 0.41 eV below the conduction band (E{sub C}), respectively, were found in undoped GaInNAs. Bias-voltage dependent admittance confirmed that E1 is an interface-type defect being spatially localized at the GaInNAs/GaAs interface, while E2 is a bulk-type defect located around mid-gap of GaInNAs layer. Introduction of Sb improved the material quality which was evident from the reduction of both the interface and bulk-type defects.

  7. The CAS-NAS forum for new leaders in space science

    NASA Astrophysics Data System (ADS)

    Smith, David H.

    The space science community is thoroughly international, with numerous nations now capable of launching scientific payloads into space either independently or in concert with others. As such, it is important for national space-science advisory groups to engage with like-minded groups in other spacefaring nations. The Space Studies Board of the US National Academy of Sciences' (NAS') National Research Council has provided scientific and technical advice to NASA for more than 50 years. Over this period, the Board has developed important multilateral and bilateral partnerships with space scientists around the world. The primary multilateral partner is COSPAR, for which the Board serves as the US national committee. The Board's primary bilateral relationship is with the European Science Foundation’s European Space Science Committee. Burgeoning Chinese space activities have resulted in several attempts in the past decade to open a dialogue between the Board and space scientists in China. On each occasion, the external political environment was not conducive to success. The most recent efforts to engage the Chinese space researchers began in 2011 and have proved particularly successful. Although NASA is currently prohibited from engaging in bilateral activities with China, the Board has established a fruitful dialogue with its counterpart in the Chinese Academy of Sciences (CAS). A joint NAS-CAS activity, the Forum for New Leaders in Space Science, has been established to provide opportunities for a highly select group of young space scientists from China and the United States to discuss their research activities in an intimate and collegial environment at meetings to be held in both nations. The presentation will describe the current state of US-China space relations, discuss the goals of the joint NAS-CAS undertaking and report on the activities at the May, 2014, Forum in Beijing and the planning for the November, 2014, Forum in Irvine, California.

  8. Improved container electrode coatings for Na/S battery systems. Final report

    SciTech Connect

    Hunt, T.K.

    1995-08-01

    Current sodium sulfur (Na/S) battery systems utilize the fast ion conducting properties of sodium beta{double_prime}-alumina electrolyte (BASE) to create high energy density sodium-sulfur electrochemical cells which can be used as components of secondary batteries. Since the days when these cells were invented at the Ford Motor Company Scientific Laboratory by J.T. Kummer and N. Weber, problems with container electrode corrosion have troubled the Na/S systems that have been developed in the many laboratories. In an unpublished investigation carried out at the Ford Motor Company laboratory, it was shown that titanium nitride films sputter deposited onto aluminum substrates under the appropriate conditions can exhibit excellent resistance to corrosion by sodium polysulfide melts. In the work carried out here, the corrosion resistant properties of TiN coatings sputter deposited on Al substrates have been investigated. TiN sputter coated aluminum samples were tested under static conditions in sodium sulfide melts and in Na/S cells under the range of electrochemical conditions needed for battery operation. The sputter deposited coatings produced in these experiments exhibited satisfactory corrosion resistance in the static tests but degraded under full cell operation. Tests of TiN coatings deposited by reactive ion-plating (IP), a common commercial process, showed excellent corrosion and electrical performance in both static and complete cell testing. Charge/discharge testing of sulfur core cells with IP coatings for over 350 cycles to 70 % depth of discharge has shown only very minor changes in cell performance and the tests are continuing.

  9. UAS Integration Into the NAS: An Examination of Baseline Compliance in the Current Airspace System

    NASA Technical Reports Server (NTRS)

    Fern, Lisa; Kenny, Caitlin A.; Shively, Robert J.; Johnson, Walter

    2012-01-01

    As a result of the FAA Modernization and Reform Act of 2012, Unmanned Aerial Systems (UAS) are expected to be integrated into the National Airspace System (NAS) by 2015. Several human factors challenges need to be addressed before UAS can safely and routinely fly in the NAS with manned aircraft. Perhaps the most significant challenge is for the UAS to be non-disruptive to the air traffic management system. Another human factors challenge is how to provide UAS pilots with intuitive traffic information in order to support situation awareness (SA) of their airspace environment as well as a see-and-avoid capability comparable to manned aircraft so that a UAS pilot could safely maneuver the aircraft to maintain separation and collision avoidance if necessary. A simulation experiment was conducted to examine baseline compliance of UAS operations in the current airspace system. Researchers also examined the effects of introducing a Cockpit Situation Display (CSD) into a UAS Ground Control Station (GCS) on UAS pilot performance, workload and situation awareness while flying in a positively controlled sector. Pilots were tasked with conducting a highway patrol police mission with a Medium Altitude Long Endurance (MALE) UAS in L.A. Center airspace with two mission objectives: 1) to reroute the UAS when issued new instructions from their commander, and 2) to communicate with Air Traffic Control (ATC) to negotiate flight plan changes and respond to vectoring and altitude change instructions. Objective aircraft separation data, workload ratings, SA data, and subjective ratings regarding UAS operations in the NAS were collected. Results indicate that UAS pilots were able to comply appropriately with ATC instructions. In addition, the introduction of the CSD improved pilot SA and reduced workload associated with UAS and ATC interactions.

  10. NAS (Numerical Aerodynamic Simulation Program) technical summaries, March 1989 - February 1990

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Given here are selected scientific results from the Numerical Aerodynamic Simulation (NAS) Program's third year of operation. During this year, the scientific community was given access to a Cray-2 and a Cray Y-MP supercomputer. Topics covered include flow field analysis of fighter wing configurations, large-scale ocean modeling, the Space Shuttle flow field, advanced computational fluid dynamics (CFD) codes for rotary-wing airloads and performance prediction, turbulence modeling of separated flows, airloads and acoustics of rotorcraft, vortex-induced nonlinearities on submarines, and standing oblique detonation waves.

  11. The OpenMP Implementation of NAS Parallel Benchmarks and its Performance

    NASA Technical Reports Server (NTRS)

    Jin, Hao-Qiang; Frumkin, Michael; Yan, Jerry

    1999-01-01

    As the new ccNUMA architecture became popular in recent years, parallel programming with compiler directives on these machines has evolved to accommodate new needs. In this study, we examine the effectiveness of OpenMP directives for parallelizing the NAS Parallel Benchmarks. Implementation details will be discussed and performance will be compared with the MPI implementation. We have demonstrated that OpenMP can achieve very good results for parallelization on a shared memory system, but effective use of memory and cache is very important.

  12. A Framework for Safe Integration of Small UAS Into the NAS

    NASA Technical Reports Server (NTRS)

    Logan, Michael J.; Bland, Geoffrey; Murray, Jennifer

    2011-01-01

    This paper discusses a proposed framework for the safe integration of small unmanned aerial systems (sUAS) into the National Airspace System (NAS). The paper examines the potential uses of sUAS to build an understanding of the location and frequency of potential future flight operations based on the future applications of the sUAS systems. The paper then examines the types of systems that would be required to meet the application-level demand to determine classes of platforms and operations. Finally, a framework is proposed for both airworthiness and operations that attempts to balance safety with utility for these important systems.

  13. 5'-coding sequence of the nasA gene of Azotobacter vinelandii is required for efficient expression.

    PubMed

    Wang, Baomin; Wang, Yumei; Kennedy, Christina

    2014-10-01

    The operon nasACBH in Azotobacter vinelandii encodes nitrate and nitrite reductases that sequentially reduce nitrate to nitrite and to ammonium for nitrogen assimilation into organic molecules. Our previous analyses showed that nasACBH expression is subject to antitermination regulation that occurs upstream of the nasA gene in response to the availability of nitrate and nitrite. In this study, we continued expression analyses of the nasA gene and observed that the nasA 5'-coding sequence plays an important role in gene expression, as demonstrated by the fact that deletions caused over sixfold reduction in the expression of the lacZ reporter gene. Further analysis suggests that the nasA 5'-coding sequence promotes gene expression in a way that is not associated with weakened transcript folding around the translational initiation region or codon usage bias. The findings from this study imply that there exists potential to improve gene expression in A. vinelandii by optimizing 5'-coding sequences. PMID:25110215

  14. InGaN/Dilute-As GaNAs Interface Quantum Well for Red Emitters

    NASA Astrophysics Data System (ADS)

    Tan, Chee-Keong; Borovac, Damir; Sun, Wei; Tansu, Nelson

    2016-01-01

    The design of InGaN/dilute-As GaNAs interface quantum well (QW) leads to significant redshift in the transition wavelength with improvement in electron-hole wave function overlap and spontaneous emission rate as compared to that of the conventional In0.2Ga0.8N QW. By using self-consistent six-band k·p band formalism, the nitride active region consisting of 30?Å In0.2Ga0.8N and 10?Å GaN0.95As0.05 interface QW leads to 623.52?nm emission wavelength in the red spectral regime. The utilization of 30?Å In0.2Ga0.8N/10?Å GaN0.95As0.05 interface QW also leads to 8.5 times enhancement of spontaneous emission rate attributed by the improvement in electron-hole wavefunction overlap, as compared to that of conventional 30?Å In0.35Ga0.65N QW for red spectral regime. In addition, the transition wavelength of the interface QW is relatively unaffected by the thickness of the dilute-As GaNAs interface layer (beyond 10?Å). The analysis indicates the potential of using interface QW concept in nitride-based light-emitting diodes for long wavelength emission.

  15. InGaN/Dilute-As GaNAs Interface Quantum Well for Red Emitters

    PubMed Central

    Tan, Chee-Keong; Borovac, Damir; Sun, Wei; Tansu, Nelson

    2016-01-01

    The design of InGaN/dilute-As GaNAs interface quantum well (QW) leads to significant redshift in the transition wavelength with improvement in electron-hole wave function overlap and spontaneous emission rate as compared to that of the conventional In0.2Ga0.8N QW. By using self-consistent six-band k·p band formalism, the nitride active region consisting of 30 Å In0.2Ga0.8N and 10 Å GaN0.95As0.05 interface QW leads to 623.52 nm emission wavelength in the red spectral regime. The utilization of 30 Å In0.2Ga0.8N/10 Å GaN0.95As0.05 interface QW also leads to 8.5 times enhancement of spontaneous emission rate attributed by the improvement in electron-hole wavefunction overlap, as compared to that of conventional 30 Å In0.35Ga0.65N QW for red spectral regime. In addition, the transition wavelength of the interface QW is relatively unaffected by the thickness of the dilute-As GaNAs interface layer (beyond 10 Å). The analysis indicates the potential of using interface QW concept in nitride-based light-emitting diodes for long wavelength emission. PMID:26758552

  16. InGaN/Dilute-As GaNAs Interface Quantum Well for Red Emitters.

    PubMed

    Tan, Chee-Keong; Borovac, Damir; Sun, Wei; Tansu, Nelson

    2016-01-01

    The design of InGaN/dilute-As GaNAs interface quantum well (QW) leads to significant redshift in the transition wavelength with improvement in electron-hole wave function overlap and spontaneous emission rate as compared to that of the conventional In0.2Ga0.8N QW. By using self-consistent six-band k·p band formalism, the nitride active region consisting of 30?Å In0.2Ga0.8N and 10?Å GaN0.95As0.05 interface QW leads to 623.52?nm emission wavelength in the red spectral regime. The utilization of 30?Å In0.2Ga0.8N/10?Å GaN0.95As0.05 interface QW also leads to 8.5 times enhancement of spontaneous emission rate attributed by the improvement in electron-hole wavefunction overlap, as compared to that of conventional 30?Å In0.35Ga0.65N QW for red spectral regime. In addition, the transition wavelength of the interface QW is relatively unaffected by the thickness of the dilute-As GaNAs interface layer (beyond 10?Å). The analysis indicates the potential of using interface QW concept in nitride-based light-emitting diodes for long wavelength emission. PMID:26758552

  17. Growth optimization and optical properties of AlGaNAs alloys

    SciTech Connect

    Kolhatkar, Gitanjali; Boucherif, Abderraouf; Aimez, Vincent; Arès, Richard; Valdivia, Christopher E.; Wallace, Steven G.; Fafard, Simon

    2014-04-28

    The effect of Al on the surface morphology of chemical beam epitaxy grown AlGaNAs alloys is studied. Pits attributed to N clustering appearing on the dilute nitride surface become smaller, denser, and more uniformly distributed in the presence of Al. This reveals that the introduction of Al results in more homogenous N atoms spatial distribution. A growth temperature study reveals the formation of 3D structures at high temperature due to phase separation. The density of these structures decreases, while their diameter and height increase when the temperature is raised from 380?°C to 565?°C. At growth temperatures in the 380–420?°C range, the phase separation is suppressed and the growth mode is 2D. At 420?°C, the N incorporation is also maximized, making it the optimum temperature. The absorption coefficient and the bandgap of AlGaNAs alloys are extracted from transmittance measurement. A good agreement is obtained between the experimentally measured bandgap and the theoretical values calculated using the band anticrossing model. A bandgap as low as 1.22?eV was reached using Al and N concentrations of ?15% and ?3.4%, respectively.

  18. Web Prep: How to Prepare NAS Reports For Publication on the Web

    NASA Technical Reports Server (NTRS)

    Walatka, Pamela; Balakrishnan, Prithika; Clucas, Jean; McCabe, R. Kevin; Felchle, Gail; Brickell, Cristy

    1996-01-01

    This document contains specific advice and requirements for NASA Ames Code IN authors of NAS reports. Much of the information may be of interest to other authors writing for the Web. WebPrep has a graphic Table of Contents in the form of a WebToon, which simulates a discussion between a scientist and a Web publishing consultant. In the WebToon, Frequently Asked Questions about preparing reports for the Web are linked to relevant text in the body of this document. We also provide a text-only Table of Contents. The text for this document is divided into chapters: each chapter corresponds to one frame of the WebToons. The chapter topics are: converting text to HTML, converting 2D graphic images to gif, creating imagemaps and tables, converting movie and audio files to Web formats, supplying 3D interactive data, and (briefly) JAVA capabilities. The last chapter is specifically for NAS staff authors. The Glossary-Index lists web related words and links to topics covered in the main text.

  19. UAS Integration in the NAS Project: Integrated Test and Evaluation (IT&E) Flight Test 3. Revision E

    NASA Technical Reports Server (NTRS)

    Marston, Michael

    2015-01-01

    The desire and ability to fly Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS) is of increasing urgency. The application of unmanned aircraft to perform national security, defense, scientific, and emergency management are driving the critical need for less restrictive access by UAS to the NAS. UAS represent a new capability that will provide a variety of services in the government (public) and commercial (civil) aviation sectors. The growth of this potential industry has not yet been realized due to the lack of a common understanding of what is required to safely operate UAS in the NAS. NASA's UAS Integration into the NAS Project is conducting research in the areas of Separation Assurance/Sense and Avoid Interoperability, Human Systems Integration (HSI), and Communication to support reducing the barriers of UAS access to the NAS. This research is broken into two research themes namely, UAS Integration and Test Infrastructure. UAS Integration focuses on airspace integration procedures and performance standards to enable UAS integration in the air transportation system, covering Sense and Avoid (SAA) performance standards, command and control performance standards, and human systems integration. The focus of Test Infrastructure is to enable development and validation of airspace integration procedures and performance standards, including the integrated test and evaluation. In support of the integrated test and evaluation efforts, the Project will develop an adaptable, scalable, and schedulable relevant test environment capable of evaluating concepts and technologies for unmanned aircraft systems to safely operate in the NAS. To accomplish this task, the Project will conduct a series of Human-in-the-Loop and Flight Test activities that integrate key concepts, technologies and/or procedures in a relevant air traffic environment. Each of the integrated events will build on the technical achievements, fidelity and complexity of the previous tests and technical simulations, resulting in research findings that support the development of regulations governing the access of UAS into the NAS.

  20. NAS Demand Predictions, Transportation Systems Analysis Model (TSAM) Compared with Other Forecasts

    NASA Technical Reports Server (NTRS)

    Viken, Jeff; Dollyhigh, Samuel; Smith, Jeremy; Trani, Antonio; Baik, Hojong; Hinze, Nicholas; Ashiabor, Senanu

    2006-01-01

    The current work incorporates the Transportation Systems Analysis Model (TSAM) to predict the future demand for airline travel. TSAM is a multi-mode, national model that predicts the demand for all long distance travel at a county level based upon population and demographics. The model conducts a mode choice analysis to compute the demand for commercial airline travel based upon the traveler s purpose of the trip, value of time, cost and time of the trip,. The county demand for airline travel is then aggregated (or distributed) to the airport level, and the enplanement demand at commercial airports is modeled. With the growth in flight demand, and utilizing current airline flight schedules, the Fratar algorithm is used to develop future flight schedules in the NAS. The projected flights can then be flown through air transportation simulators to quantify the ability of the NAS to meet future demand. A major strength of the TSAM analysis is that scenario planning can be conducted to quantify capacity requirements at individual airports, based upon different future scenarios. Different demographic scenarios can be analyzed to model the demand sensitivity to them. Also, it is fairly well know, but not well modeled at the airport level, that the demand for travel is highly dependent on the cost of travel, or the fare yield of the airline industry. The FAA projects the fare yield (in constant year dollars) to keep decreasing into the future. The magnitude and/or direction of these projections can be suspect in light of the general lack of airline profits and the large rises in airline fuel cost. Also, changes in travel time and convenience have an influence on the demand for air travel, especially for business travel. Future planners cannot easily conduct sensitivity studies of future demand with the FAA TAF data, nor with the Boeing or Airbus projections. In TSAM many factors can be parameterized and various demand sensitivities can be predicted for future travel. These resulting demand scenarios can be incorporated into future flight schedules, therefore providing a quantifiable demand for flights in the NAS for a range of futures. In addition, new future airline business scenarios are investigated that illustrate when direct flights can replace connecting flights and larger aircraft can be substituted, only when justified by demand.

  1. Utilizing Traveler Demand Modeling to Predict Future Commercial Flight Schedules in the NAS

    NASA Technical Reports Server (NTRS)

    Viken, Jeff; Dollyhigh, Samuel; Smith, Jeremy; Trani, Antonio; Baik, Hojong; Hinze, Nicholas; Ashiabor, Senanu

    2006-01-01

    The current work incorporates the Transportation Systems Analysis Model (TSAM) to predict the future demand for airline travel. TSAM is a multi-mode, national model that predicts the demand for all long distance travel at a county level based upon population and demographics. The model conducts a mode choice analysis to compute the demand for commercial airline travel based upon the traveler s purpose of the trip, value of time, cost and time of the trip,. The county demand for airline travel is then aggregated (or distributed) to the airport level, and the enplanement demand at commercial airports is modeled. With the growth in flight demand, and utilizing current airline flight schedules, the Fratar algorithm is used to develop future flight schedules in the NAS. The projected flights can then be flown through air transportation simulators to quantify the ability of the NAS to meet future demand. A major strength of the TSAM analysis is that scenario planning can be conducted to quantify capacity requirements at individual airports, based upon different future scenarios. Different demographic scenarios can be analyzed to model the demand sensitivity to them. Also, it is fairly well know, but not well modeled at the airport level, that the demand for travel is highly dependent on the cost of travel, or the fare yield of the airline industry. The FAA projects the fare yield (in constant year dollars) to keep decreasing into the future. The magnitude and/or direction of these projections can be suspect in light of the general lack of airline profits and the large rises in airline fuel cost. Also, changes in travel time and convenience have an influence on the demand for air travel, especially for business travel. Future planners cannot easily conduct sensitivity studies of future demand with the FAA TAF data, nor with the Boeing or Airbus projections. In TSAM many factors can be parameterized and various demand sensitivities can be predicted for future travel. These resulting demand scenarios can be incorporated into future flight schedules, therefore providing a quantifiable demand for flights in the NAS for a range of futures. In addition, new future airline business scenarios are investigated that illustrate when direct flights can replace connecting flights and larger aircraft can be substituted, only when justified by demand.

  2. Comparison of 250 MHz R10K Origin 2000 and 400 MHz Origin 2000 Using NAS Parallel Benchmarks

    NASA Technical Reports Server (NTRS)

    Turney, Raymond D.; Thigpen, William W. (Technical Monitor)

    2001-01-01

    This report describes results of benchmark tests on Steger, a 250 MHz Origin 2000 system with R10K processors, currently installed at the NASA Ames National Advanced Supercomputing (NAS) facility. For comparison purposes, the tests were also run on Lomax, a 400 MHz Origin 2000 with R12K processors. The BT, LU, and SP application benchmarks in the NAS Parallel Benchmark Suite and the kernel benchmark FT were chosen to measure system performance. Having been written to measure performance on Computational Fluid Dynamics applications, these benchmarks are assumed appropriate to represent the NAS workload. Since the NAS runs both message passing (MPI) and shared-memory, compiler directive type codes, both MPI and OpenMP versions of the benchmarks were used. The MPI versions used were the latest official release of the NAS Parallel Benchmarks, version 2.3. The OpenMP versions used were PBN3b2, a beta version that is in the process of being released. NPB 2.3 and PBN3b2 are technically different benchmarks, and NPB results are not directly comparable to PBN results.

  3. Specific structural and compositional properties of (GaIn)(NAs) and their influence on optoelectronic device performance

    NASA Astrophysics Data System (ADS)

    Volz, Kerstin; Torunski, Torsten; Kunert, Bernardette; Rubel, Oleg; Nau, Siegfried; Reinhard, Stefan; Stolz, Wolfgang

    2004-12-01

    We have grown (GaIn)(NAs) lattice-matched bulk as well as compressively strained multi-quantum-well structures by metal-organic vapour-phase epitaxy (MOVPE) suitable for either solar cell or laser applications, respectively. By applying a specific novel TEM dark-field technique columnar strain fields, which are possibly caused by chain-like N ordering in the samples, have been detected. Valence force field calculations show that indeed these chains are energetically stable in Ga(NAs). This chain-like ordering can be dissolved in (GaIn)(NAs), however, upon appropriate annealing, as verified experimentally. On the other hand we find that device performance especially of lasers is limited by carbon impurities in the active (GaIn)(NAs) region of the lasers. The strong affinity of N-C results in an enhanced incorporation of C if the N content in the material is increased. The paper also shows the sources of C incorporation in (GaIn)(NAs) MOVPE growth and how its incorporation can possibly be avoided.

  4. >8W GaInNAs VECSEL emitting at 615 nm

    NASA Astrophysics Data System (ADS)

    Leinonen, Tomi; Penttinen, Jussi-Pekka; Korpijärvi, Ville-Markus; Kantola, Emmi; Guina, Mircea

    2015-03-01

    We report a high-power VECSEL emitting <8W around 615 nm. The gain chip of the laser was grown by plasmaassisted molecular beam epitaxy and it comprised 10 GaInNAs quantum wells. The VECSEL cavity had a V-shaped geometry and a 10-mm-long non-critically phase-matched LBO crystal for second harmonic generation. The cavity incorporated also an etalon and a birefringent filter for controlling the output wavelength. With the aid of the secondharmonic output and the infrared light leaking out from the laser cavity, the single-pass conversion efficiency of the crystal was estimated to have a value of 0.75%.

  5. 615 nm GaInNAs VECSEL with output power above 10 W.

    PubMed

    Kantola, Emmi; Leinonen, Tomi; Penttinen, Jussi-Pekka; Korpijärvi, Ville-Markus; Guina, Mircea

    2015-08-10

    A high-power optically-pumped vertical-external-cavity surface-emitting laser (VECSEL) generating 10.5 W of cw output power at 615 nm is reported. The gain mirror incorporated 10 GaInNAs quantum wells and was designed to have an emission peak in the 1230 nm range. The fundamental emission was frequency doubled to the red spectral range by using an intra-cavity nonlinear LBO crystal. The maximum optical-to-optical conversion efficiency was 17.5%. The VECSEL was also operated in pulsed mode by directly modulating the pump laser to produce light pulses with duration of ~1.5 µs. The maximum peak power for pulsed operation (pump limited) was 13.8 W. This corresponded to an optical-to-optical conversion efficiency of 20.4%. PMID:26367883

  6. Security Risk Assessment Process for UAS in the NAS CNPC Architecture

    NASA Technical Reports Server (NTRS)

    Iannicca, Dennis C.; Young, Dennis P.; Thadani, Suresh K.; Winter, Gilbert A.

    2013-01-01

    This informational paper discusses the risk assessment process conducted to analyze Control and Non-Payload Communications (CNPC) architectures for integrating civil Unmanned Aircraft Systems (UAS) into the National Airspace System (NAS). The assessment employs the National Institute of Standards and Technology (NIST) Risk Management framework to identify threats, vulnerabilities, and risks to these architectures and recommends corresponding mitigating security controls. This process builds upon earlier work performed by RTCA Special Committee (SC) 203 and the Federal Aviation Administration (FAA) to roadmap the risk assessment methodology and to identify categories of information security risks that pose a significant impact to aeronautical communications systems. A description of the deviations from the typical process is described in regards to this aeronautical communications system. Due to the sensitive nature of the information, data resulting from the risk assessment pertaining to threats, vulnerabilities, and risks is beyond the scope of this paper.

  7. Characterization of a Dominant Electron Trap in GaNAs Using Deep-Level Spectroscopy

    SciTech Connect

    Johnston, S. W.; Kurtz, S. R.

    2006-08-01

    Dilute-nitrogen GaNAs epitaxial layers grown by metal-organic chemical vapor deposition were characterized by deep-level transient spectroscopy (DLTS). For all samples, the dominant DLTS signal corresponds to an electron trap having an activation energy of about 0.25 to 0.35 eV. The minority-carrier trap density in the p-type material is quantified based on computer simulation of the devices. The simulations show that only about 2% of the traps in the depleted layer are filled during the transient. The fraction of the traps that are filled depends strongly on the depth of the trap, but only weakly on the doping of the layers and on the conduction-band offset. The simulations provide a pathway to obtain semi-quantitative data for analysis of minority-carrier traps by DLTS.

  8. Temperature coefficients for GaInP/GaAs/GaInNAsSb solar cells

    NASA Astrophysics Data System (ADS)

    Aho, Arto; Isoaho, Riku; Tukiainen, Antti; Polojärvi, Ville; Aho, Timo; Raappana, Marianna; Guina, Mircea

    2015-09-01

    We report the temperature coefficients for MBE-grown GaInP/GaAs/GaInNAsSb multijunction solar cells and the corresponding single junction sub-cells. Temperature-dependent current-voltage measurements were carried out using a solar simulator equipped with a 1000 W Xenon lamp and a three-band AM1.5D simulator. The triple-junction cell exhibited an efficiency of 31% at AM1.5G illumination and an efficiency of 37-39% at 70x real sun concentration. The external quantum efficiency was also measured at different temperatures. The temperature coefficients up to 80°C, for the open circuit voltage, the short circuit current density, and the conversion efficiency were determined to be -7.5 mV/°C, 0.040 mA/cm2/°C, and -0.09%/°C, respectively.

  9. Development of computer program NAS3D using Vector processing for geometric nonlinear analysis of structures

    NASA Technical Reports Server (NTRS)

    Mangalgiri, P. D.; Prabhakaran, R.

    1986-01-01

    An algorithm for vectorized computation of stiffness matrices of an 8 noded isoparametric hexahedron element for geometric nonlinear analysis was developed. This was used in conjunction with the earlier 2-D program GAMNAS to develop the new program NAS3D for geometric nonlinear analysis. A conventional, modified Newton-Raphson process is used for the nonlinear analysis. New schemes for the computation of stiffness and strain energy release rates is presented. The organization the program is explained and some results on four sample problems are given. The study of CPU times showed that savings by a factor of 11 to 13 were achieved when vectorized computation was used for the stiffness instead of the conventional scalar one. Finally, the scheme of inputting data is explained.

  10. Security Risk Assessment Process for UAS in the NAS CNPC Architecture

    NASA Technical Reports Server (NTRS)

    Iannicca, Dennis Christopher; Young, Daniel Paul; Suresh, Thadhani; Winter, Gilbert A.

    2013-01-01

    This informational paper discusses the risk assessment process conducted to analyze Control and Non-Payload Communications (CNPC) architectures for integrating civil Unmanned Aircraft Systems (UAS) into the National Airspace System (NAS). The assessment employs the National Institute of Standards and Technology (NIST) Risk Management framework to identify threats, vulnerabilities, and risks to these architectures and recommends corresponding mitigating security controls. This process builds upon earlier work performed by RTCA Special Committee (SC) 203 and the Federal Aviation Administration (FAA) to roadmap the risk assessment methodology and to identify categories of information security risks that pose a significant impact to aeronautical communications systems. A description of the deviations from the typical process is described in regards to this aeronautical communications system. Due to the sensitive nature of the information, data resulting from the risk assessment pertaining to threats, vulnerabilities, and risks is beyond the scope of this paper

  11. Seismic reflection exploration of geothermal reservoir at Naval Air Station (NAS) Fallon, Nevada

    NASA Astrophysics Data System (ADS)

    Alay G., Gebregiorgis

    The Primary objective of this study is to increase geologic and tectonic understanding of the geothermal resources at the Naval Air Station (NAS) Fallon, Nevada. The seismic reflection method is employed to study faults, fractures and other tectonic structures in the subsurface in order to identify geothermal drill targets. The efficiency of geothermal systems is strongly dependent on water circulation. Discrete faults may be permeable and provide pathways for water flow depending on the fracture density. It is therefore desirable to detect and map faults and fracture zones and characterize their physical properties when evaluating a geothermal prospect. The seismic data for this project were provided by the NAS environmental research program in Ridgecrest, CA. However, the data collection information was not available so the work includes determining the line geometry and mapping shot points to field files in order to process the data. ProMAX 2D(TM) is the software used to determine the geometry and to process the data. Data processing includes eliminating noise, datum and refraction statics, trace muting, bandpass filter, automatic gain control, amplitude recovery, CMP sorting, velocity analysis and NMO correction, stacking and migration. The results of this study indicate the presence of thick basin fill including Tertiary and Quaternary sediments underlain by Tertiary basalts which are interpreted to be capping rocks for the geothermal reservoirs. This seismic reflection study also reveals the presence of strongly fractured pre-Tertiary basement complex with their top at about 1500m on the north and west and about 900 m on the eastern and southern part of the study area.

  12. Benefits of a Unified LaSRS++ Simulation for NAS-Wide and High-Fidelity Modeling

    NASA Technical Reports Server (NTRS)

    Glaab, Patricia; Madden, Michael

    2014-01-01

    The LaSRS++ high-fidelity vehicle simulation was extended in 2012 to support a NAS-wide simulation mode. Since the initial proof-of-concept, the LaSRS++ NAS-wide simulation is maturing into a research-ready tool. A primary benefit of this new capability is the consolidation of the two modeling paradigms under a single framework to save cost, facilitate iterative concept testing between the two tools, and to promote communication and model sharing between user communities at Langley. Specific benefits of each type of modeling are discussed along with the expected benefits of the unified framework. Current capability details of the LaSRS++ NAS-wide simulations are provided, including the visualization tool, live data interface, trajectory generators, terminal routing for arrivals and departures, maneuvering, re-routing, navigation, winds, and turbulence. The plan for future development is also described.

  13. Efficient GaInNAs Gain Mirrors for Semiconductor Disk Lasers at 1.18 {mu}m and 1.22 {mu}m

    SciTech Connect

    Korpijaervi, Ville-Markus; Puustinen, Janne; Leinonen, Tomi; Rautiainen, Jussi; Haerkoenen, Antti; Hakkarainen, Teemu; Guina, Mircea

    2010-11-10

    We report two GaInNAs/GaAs semiconductor disk lasers emitting at the wavelengths of 1180 nm and 1220 nm. The lasers generated 5 W and 7 W output powers, respectively, at a mount temperature of 15 deg. C. Both the gain mirrors were grown by molecular beam epitaxy and consisted of a GaAs/AlAs distributed Bragg reflector and an active region with 10 GaInNAs/GaNAs/GaAs QWs.

  14. NasT-Mediated Antitermination Plays an Essential Role in the Regulation of the Assimilatory Nitrate Reductase Operon in Azotobacter vinelandii

    PubMed Central

    Pierson, Leland S.; Rensing, Christopher; Gunatilaka, Malkanthi K.; Kennedy, Christina

    2012-01-01

    Azotobacter vinelandii is a well-studied model system for nitrogen fixation in bacteria. Regulation of nitrogen fixation in A. vinelandii is independent of NtrB/NtrC, a conserved nitrogen regulatory system in proteobacteria. Previous work showed that an ntrC mutation in A. vinelandii resulted in a loss of induction of assimilatory nitrate and nitrite reductases encoded by the nasAB operon. In addition to NtrC, several other proteins, including NasT, a protein containing a potential RNA-binding domain ANTAR (AmiR and NasR transcription antitermination regulators), have been implicated in nasAB regulation. In this work, we characterize the sequence upstream of nasA and identify several DNA sequence elements, including two potential NtrC binding sites and a putative intrinsic transcriptional terminator upstream of nasA that are potentially involved in nasAB regulation. Our analyses confirm that the nasAB promoter, PnasA, is under NtrC control. However, unlike NtrC-regulated promoters in enteric bacteria, PnasA shows high activity in the presence of ammonium; in addition, the PnasA activity is altered in the nifA gene mutation background. We discuss the implication of these results on NtrC-mediated regulation in A. vinelandii. Our study provides direct evidence that induction of nasAB is regulated by NasT-mediated antitermination, which occurs within the leader region of the operon. The results also support the hypothesis that NasT binds the promoter proximal hairpin of nasAB for its regulatory function, which contributes to the understanding of the regulatory mechanism of ANTAR-containing antiterminators. PMID:22773651

  15. Efficient GaInNAs Gain Mirrors for Semiconductor Disk Lasers at 1.18 μm and 1.22 μm

    NASA Astrophysics Data System (ADS)

    Korpijärvi, Ville-Markus; Puustinen, Janne; Leinonen, Tomi; Rautiainen, Jussi; Härkönen, Antti; Hakkarainen, Teemu; Guina, Mircea

    2010-11-01

    We report two GaInNAs/GaAs semiconductor disk lasers emitting at the wavelengths of 1180 nm and 1220 nm. The lasers generated 5 W and 7 W output powers, respectively, at a mount temperature of 15° C. Both the gain mirrors were grown by molecular beam epitaxy and consisted of a GaAs/AlAs distributed Bragg reflector and an active region with 10 GaInNAs/GaNAs/GaAs QWs.

  16. Direct visualization of the N impurity state in dilute GaNAs using scanning tunneling microscopy

    NASA Astrophysics Data System (ADS)

    Ishida, Nobuyuki; Jo, Masafumi; Mano, Takaaki; Sakuma, Yoshiki; Noda, Takeshi; Fujita, Daisuke

    2015-10-01

    The interaction between nitrogen (N) impurity states in III-V compounds plays a key role in controlling optoelectronic properties of the host materials. Here, we use scanning tunneling microscopy to characterize the spatial distribution and electronic properties of N impurity states in dilute GaNAs. We demonstrated that the N impurity states can be directly visualized by taking empty state current images using the multipass scanning method. The N impurity states broadened over several nanometers and exhibited a highly anisotropic distribution with a bowtie-like shape on the GaAs(110) surface, which can be explained by anisotropic propagation of strain along the zigzag chains of Ga and As atoms in the {110} plane. Our experimental findings provide strong insights into a possible role of N impurity states in modifying properties of the host materials.The interaction between nitrogen (N) impurity states in III-V compounds plays a key role in controlling optoelectronic properties of the host materials. Here, we use scanning tunneling microscopy to characterize the spatial distribution and electronic properties of N impurity states in dilute GaNAs. We demonstrated that the N impurity states can be directly visualized by taking empty state current images using the multipass scanning method. The N impurity states broadened over several nanometers and exhibited a highly anisotropic distribution with a bowtie-like shape on the GaAs(110) surface, which can be explained by anisotropic propagation of strain along the zigzag chains of Ga and As atoms in the {110} plane. Our experimental findings provide strong insights into a possible role of N impurity states in modifying properties of the host materials. Electronic supplementary information (ESI) available: Identification of N impurity positions in terms of depth of depressions in the filled state topographic image. Filled state topographic images of N impurity in the fourth plane. Slight modification of topographic height due to existence of N impurity in the sixth plane. Current images taken around surface adsorbates. Current and dI/dV images extracted from current imaging tunneling spectroscopy data. Current image of fifth plane N impurity without height correction. Line profiles taken along the [001] and [1&cmb.macr;10] directions for N impurities in first to eighth planes. Differential tunneling conductance spectra obtained above N impurities in first to eighth planes. Position dependence of differential tunneling conductance spectra obtained at N impurity in the second plane. Detailed growth conditions of each N-doped GaAs layer. See DOI: 10.1039/c5nr04193g

  17. EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments (External Review Draft)

    EPA Science Inventory

  1. EPA'S REANALYSIS OF KEY ISSUES RELATED TO DIOXIN TOXICITY AND RESPONSE TO NAS COMMENTS (VOLUME 1) (INTERAGENCY SCIENCE DISCUSSION DRAFT)

    EPA Science Inventory

    EPA is releasing the draft report, EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments (Volume 1), that was distributed to Federal agencies and White House Offices for comment during the Science Discussion step of the National Academy of Sciences (NAS) Study entitled The Effect of Climate Change on Indoor Air Quality and Public Health.

    EPA Science Inventory

    The Institute of Medicine of the NAS is conducting a study to evaluate the state of scientific understanding of the effects of climate change on indoor air quality and public health. General topics may include the likely impacts of climate change in the U.S. on the indoor environ...

  2. 78 FR 46497 - Amendment of Class D and E Airspace, and Establishment of Class E Airspace; Oceana NAS, VA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-01

    ... airspace, and establish Class E airspace at Oceana Naval Air Station, (NAS), VA, (78 FR 21084). Interested... TRANSPORTATION Federal Aviation Administration 14 CFR Part 71 Amendment of Class D and E Airspace, and...: Final rule. SUMMARY: This action amends the Class D and Class E airspace operating hours,...

  3. EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments (External Review Draft)

    EPA Science Inventory

  1. Arbuscular mycorrhizal symbiosis alters the expression patterns of three key iron homeostasis genes, ZmNAS1, ZmNAS3, and ZmYS1, in S deprived maize plants

    PubMed Central

    Chorianopoulou, Styliani N.; Saridis, Yiorgos I.; Dimou, Maria; Katinakis, Panagiotis; Bouranis, Dimitris L.

    2015-01-01

    Nicotianamine is an essential molecule for Fe homeostasis in plants, its primary precursor is the S-containing compound methionine, and it is biosynthesized by the enzyme family of nicotianamine synthases (NASs). In maize, a graminaceous plant that follows Strategy II for Fe uptake, ZmNAS genes can be subgrouped into two classes, according to their roles and tissue specific expression profiles. In roots, the genes of class I provide NA for the production of deoxymugineic acid (DMA), which is secreted to the rhizosphere and chelates Fe(III). The Fe(III)-DMA complex is then inserted to the root via a ZmYS1 transporter. The genes of class II provide NA for local translocation and detoxification of Fe in the leaves. Due to the connection between S and Fe homeostasis, S deficiency causes Fe deprivation responses to graminaceous plants and when S is supplied, these responses are inverted. In this study, maize plants were grown in pots with sterile river sand containing FePO4 and were inoculated with the mycorrhizal fungus Rhizophagus irregularis. The plants were grown under S deficient conditions until day 60 from sowing and on that day sulfate was provided to the plants. In order to assess the impact of AM symbiosis on Fe homeostasis, the expression patterns of ZmNAS1, ZmNAS3 (representatives of ZmNAS class I and class II), and ZmYS1 were monitored before and after S supply by means of real time RT-PCR and they were used as indicators of the plant Fe status. In addition, total shoot Fe concentration was determined before and after S supply. AM symbiosis prevented Fe deprivation responses in the S deprived maize plants and iron was possibly provided directly to the mycorrhizal plants through the fungal network. Furthermore, sulfate possibly regulated the expression of all three genes revealing its potential role as signal molecule for Fe homeostasis. PMID:25941530

  2. Arbuscular mycorrhizal symbiosis alters the expression patterns of three key iron homeostasis genes, ZmNAS1, ZmNAS3, and ZmYS1, in S deprived maize plants.

    PubMed

    Chorianopoulou, Styliani N; Saridis, Yiorgos I; Dimou, Maria; Katinakis, Panagiotis; Bouranis, Dimitris L

    2015-01-01

    Nicotianamine is an essential molecule for Fe homeostasis in plants, its primary precursor is the S-containing compound methionine, and it is biosynthesized by the enzyme family of nicotianamine synthases (NASs). In maize, a graminaceous plant that follows Strategy II for Fe uptake, ZmNAS genes can be subgrouped into two classes, according to their roles and tissue specific expression profiles. In roots, the genes of class I provide NA for the production of deoxymugineic acid (DMA), which is secreted to the rhizosphere and chelates Fe(III). The Fe(III)-DMA complex is then inserted to the root via a ZmYS1 transporter. The genes of class II provide NA for local translocation and detoxification of Fe in the leaves. Due to the connection between S and Fe homeostasis, S deficiency causes Fe deprivation responses to graminaceous plants and when S is supplied, these responses are inverted. In this study, maize plants were grown in pots with sterile river sand containing FePO4 and were inoculated with the mycorrhizal fungus Rhizophagus irregularis. The plants were grown under S deficient conditions until day 60 from sowing and on that day sulfate was provided to the plants. In order to assess the impact of AM symbiosis on Fe homeostasis, the expression patterns of ZmNAS1, ZmNAS3 (representatives of ZmNAS class I and class II), and ZmYS1 were monitored before and after S supply by means of real time RT-PCR and they were used as indicators of the plant Fe status. In addition, total shoot Fe concentration was determined before and after S supply. AM symbiosis prevented Fe deprivation responses in the S deprived maize plants and iron was possibly provided directly to the mycorrhizal plants through the fungal network. Furthermore, sulfate possibly regulated the expression of all three genes revealing its potential role as signal molecule for Fe homeostasis. PMID:25941530

  3. Pressure and PL study of dilute-N GaInNAs films for applications in photovoltaics

    NASA Astrophysics Data System (ADS)

    Lindberg, George; Fukuda, Miwa; Al Khalfioui, M.; Hossain, Khalid; Sellers, Ian; Weinstein, Bernard

    2013-03-01

    Multi-junction photovoltaic devices employing dilute-N GaInNAs alloys are currently of high interest for efficient solar energy conversion. The negative band-bowing produced by introducing a few percent N into GaInAs provides a convenient way to match the 1eV component of the solar spectrum, providing recombination losses in localized states can be reduced while maintaining favorable carrier extraction. High pressure photoluminescence (PL) experiments exploring the localization of band-edge excitons in dilute-N GaInNAs films grown by plasma assisted MBE will be discussed. The effects of post-growth annealing and hydrogen incorporation on the PL spectra of the films are considered. Research supported by Amethyst Research Inc. through the State of Oklahoma, ONAP program.

  4. Nitrogen-concentration control in GaNAs/AlGaAs quantum wells using nitrogen δ-doping technique

    SciTech Connect

    Mano, Takaaki; Jo, Masafumi; Kuroda, Takashi; Noda, Takeshi; Sugimoto, Yoshimasa; Sakuma, Yoshiki; Elborg, Martin; Sakoda, Kazuaki

    2014-05-15

    GaNAs/Al{sub 0.35}Ga{sub 0.65}As multiple quantum wells (MQWs) with nitrogen δ-doping were fabricated on GaAs (100) substrates by plasma-assisted molecular beam epitaxy. High controllability of nitrogen-concentrations in the MQWs was achieved by tuning nitrogen δ-doping time. The maximum nitrogen concentration in the MQWs was 2.8%. The MQWs exhibit intense, narrow photoluminescence emission.

  5. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project - Gen-4 and Gen-5 Radio Plans

    NASA Technical Reports Server (NTRS)

    Griner, James H.

    2014-01-01

    NASA's UAS Integration in the NAS project, has partnered with Rockwell Collins to develop a concept Control and Non-Payload Communication (CNPC) system prototype radio, operating on recently allocated UAS frequency spectrum bands. This prototype radio is being used to validate initial proposed performance requirements for UAS control communications. This presentation will give an overview of the current plans for the prototype radio development.

  6. NASA's UAS Integration into the NAS: A Report on the Human Systems Integration Phase 1 Simulation Activities

    NASA Technical Reports Server (NTRS)

    Fern, Lisa; Rorie, R. Conrad; Shively, R. Jay

    2014-01-01

    In 2011 the National Aeronautics and Space Administration (NASA) began a five-year Project to address the technical barriers related to routine access of Unmanned Aerial Systems (UAS) in the National Airspace System (NAS). Planned in two phases, the goal of the first phase was to lay the foundations for the Project by identifying those barriers and key issues to be addressed to achieve integration. Phase 1 activities were completed two years into the five-year Project. The purpose of this paper is to review activities within the Human Systems Integration (HSI) subproject in Phase 1 toward its two objectives: 1) develop GCS guidelines for routine UAS access to the NAS, and 2) develop a prototype display suite within an existing Ground Control Station (GCS). The first objective directly addresses a critical barrier for UAS integration into the NAS - a lack of GCS design standards or requirements. First, the paper describes the initial development of a prototype GCS display suite and supporting simulation software capabilities. Then, three simulation experiments utilizing this simulation architecture are summarized. The first experiment sought to determine a baseline performance of UAS pilots operating in civil airspace under current instrument flight rules for manned aircraft. The second experiment examined the effect of currently employed UAS contingency procedures on Air Traffic Control (ATC) participants. The third experiment compared three GCS command and control interfaces on UAS pilot response times in compliance with ATC clearances. The authors discuss how the results of these and future simulation and flight-testing activities contribute to the development of GCS guidelines to support the safe integration of UAS into the NAS. Finally, the planned activities for Phase 2, including an integrated human-in-the-loop simulation and two flight tests are briefly described.

  7. GaInNAs/GaAs multiple quantum wells grown by gas-source molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Xin, H. P.; Tu, C. W.

    1998-05-01

    GaInNAs/GaAs multiple quantum wells (MQWs) with different N composition were successfully grown on semi-insulating GaAs substrate by gas-source molecular beam epitaxy. A nitrogen radical beam source was used to incorporate N into GaInAs layers. High resolution x-ray rocking curves measurements indicate that the N composition in GaInNAs layer was increased from 0.009 to 0.03 with increasing N2 flow rate. Photoluminescence (PL) measurements show that the PL wavelength red shifts with increasing N composition in GaInNAs layer. For a 7-period Ga0.7In0.3N0.02As0.98/GaAs MQW, a PL peak at 1.3 μm wavelength at room temperature has been successfully obtained. The band offset ΔEc for Ga0.7In0.3NxAs1-x/GaAs enlarges quickly from 0.26 eV to 0.56 eV with increasing N concentration from 0% to 3%.

  8. Suppression of non-radiative surface recombination by N incorporation in GaAs/GaNAs core/shell nanowires

    PubMed Central

    Chen, Shula L.; Chen, Weimin M.; Ishikawa, Fumitaro; Buyanova, Irina A.

    2015-01-01

    III-V semiconductor nanowires (NWs) such as GaAs NWs form an interesting artificial materials system promising for applications in advanced optoelectronic and photonic devices, thanks to the advantages offered by the 1D architecture and the possibility to combine it with the main-stream silicon technology. Alloying of GaAs with nitrogen can further enhance performance and extend device functionality via band-structure and lattice engineering. However, due to a large surface-to-volume ratio, III-V NWs suffer from severe non-radiative carrier recombination at/near NWs surfaces that significantly degrades optical quality. Here we show that increasing nitrogen composition in novel GaAs/GaNAs core/shell NWs can strongly suppress the detrimental surface recombination. This conclusion is based on our experimental finding that lifetimes of photo-generated free excitons and free carriers increase with increasing N composition, as revealed from our time-resolved photoluminescence (PL) studies. This is accompanied by a sizable enhancement in the PL intensity of the GaAs/GaNAs core/shell NWs at room temperature. The observed N-induced suppression of the surface recombination is concluded to be a result of an N-induced modification of the surface states that are responsible for the nonradiative recombination. Our results, therefore, demonstrate the great potential of incorporating GaNAs in III-V NWs to achieve efficient nano-scale light emitters. PMID:26100755

  9. Suppression of non-radiative surface recombination by N incorporation in GaAs/GaNAs core/shell nanowires

    NASA Astrophysics Data System (ADS)

    Chen, Shula L.; Chen, Weimin M.; Ishikawa, Fumitaro; Buyanova, Irina A.

    2015-06-01

    III-V semiconductor nanowires (NWs) such as GaAs NWs form an interesting artificial materials system promising for applications in advanced optoelectronic and photonic devices, thanks to the advantages offered by the 1D architecture and the possibility to combine it with the main-stream silicon technology. Alloying of GaAs with nitrogen can further enhance performance and extend device functionality via band-structure and lattice engineering. However, due to a large surface-to-volume ratio, III-V NWs suffer from severe non-radiative carrier recombination at/near NWs surfaces that significantly degrades optical quality. Here we show that increasing nitrogen composition in novel GaAs/GaNAs core/shell NWs can strongly suppress the detrimental surface recombination. This conclusion is based on our experimental finding that lifetimes of photo-generated free excitons and free carriers increase with increasing N composition, as revealed from our time-resolved photoluminescence (PL) studies. This is accompanied by a sizable enhancement in the PL intensity of the GaAs/GaNAs core/shell NWs at room temperature. The observed N-induced suppression of the surface recombination is concluded to be a result of an N-induced modification of the surface states that are responsible for the nonradiative recombination. Our results, therefore, demonstrate the great potential of incorporating GaNAs in III-V NWs to achieve efficient nano-scale light emitters.

  10. Física e Arte nas Estações do Ano

    NASA Astrophysics Data System (ADS)

    Pessôa Queiroz, Glória; da Conceição Barbosa Lima, Maria; Navarro Vasconcellos das Mercês, Maria

    2004-12-01

    The paper deals with the subject of the Four Seasons, exploring elements of Science and the Art in order to motivate students or public of museums of science and technology to understand it from their current cultural experiences and of old times. Physics joins to Astronomy to explain the phenomenon, while the use of Music and Painting make possible the immersion in the subject in way to many trips to the imagination capable to awake emotions.A proposal didactic is presented and justified for some consensus of the research in the area of teaching-learning of science, since that related to the persistent alternative conceptions concerning the causes of the changes observed at the different times of the year until the qualitative modelling of phenomena that appeals three-dimensional pedagogical models. Such proposal was developed in the activity named " Hiper interesting Talk: The Four Seasons, Science and Art" in the first Sunday of August/2003 in the Museum of Astronomy, MAST. O artigo trata do tema das Estações do Ano, explorando elementos da Ciência e da Arte como forma de motivar estudantes ou público de museus de ciência e tecnologia a compreendê-lo a partir de vivências culturais atuais e de outras épocas. A Física se junta à Astronomia para explicar o fenômeno, enquanto a Música e a Pintura possibilitam a imersão no tema em meio a muitas viagens à imaginação capazes de despertar emoções.Uma proposta didática é apresentada e justificada por consensos das muitas pesquisas na área de ensino-aprendizagem de ciências, desde os que se referem às persistentes concepções alternativas acerca das causas das mudanças observadas nas diferentes épocas do ano até à modelagem qualitativa de fenômenos que recorre a modelos pedagógicos tridimensionais. Tal proposta foi desenvolvida na atividade "Bate papo Hiperinteressante: As Quatro Estações, Ciência e Arte" realizada no primeiro domingo do mês de agosto de 2003 no Museu de Astronomia.

  11. 1.55 {mu}m GaAs/GaNAsSb/GaAs optical waveguides grown by radio frequency nitrogen plasma-assisted molecular beam epitaxy

    SciTech Connect

    Tan, K. H.; Yoon, S. F.; Loke, W. K.; Wicaksono, S.; Xu, Z.; Ng, T. K.; Lew, K. L.; Saadsaoud, N.; Zegaoui, M.; Decoster, D.; Chazelas, J.

    2008-03-17

    We demonstrate a 1.55 {mu}m GaAs/GaNAsSb/GaAs optical waveguide grown by molecular beam epitaxy as an alternative to the AlGaAs/GaAs system. The 0.4-{mu}m-thick GaNAsSb guiding layer contains {approx}3.5% of N and 9% of Sb, resulting in optical band gap of 0.88 eV. The refractive index of the GaNAsSb layer was measured from 800 to 1700 nm. The GaNAsSb layer has a refractive index value of 3.42 at 1.55 {mu}m wavelength. The propagation loss measured using the Fabry-Perot resonance method was found to be affected by nitrogen-related defect absorption.

  12. Incorporating the social dimension into hydrogeochemical investigations for rural development: the Bir Al-Nas approach for socio-hydrogeology

    NASA Astrophysics Data System (ADS)

    Re, Viviana

    2015-11-01

    A replicable multidisciplinary approach is presented for science-based groundwater management practices: Bir Al-Nas (Bottom-up IntegRated Approach for sustainabLe grouNdwater mAnagement in rural areaS). This approach provides a practical example of the concept of "socio-hydrogeology", a way of incorporating the social dimension into hydrogeological investigations, as reinforced by the translation of the Arabic bir al-nas: "the people's well". To achieve this, hydrogeologists act as "social hydrologists" during their monitoring activities, which often bring them into contact with local communities and end users (and polluters) of water. Not only can they retrieve reliable information about traditional know-how and local issues, but they can also change the public perception of science/scientists to create the basis for mutual collaboration and understanding in view of implementing improved integrated groundwater management. The final outcomes are expected to be an increased awareness of communities at the local level and a clear understanding of their water issues and needs from the very early stages of the investigation. Although the importance of using such methods in groundwater analysis and management is widely recognized, hydrogeological investigations are currently dominated by sectorial approaches that are easier to implement but less sustainable. The pressure of population growth, the shift towards more water-dependent economies, climate change and its impact on water availability will require scientists to use a more integrated approach, such as Bir Al-Nas, when dealing with increasing water pollution and water-scarcity issues.

  13. Remotely Operated Aircraft (ROA) Impact on the National Airspace System (NAS) Work Package: Data Modeling and Sharing Perspective for Development of a Common Operating Picture

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This report documents analyses that were performed in support of Task #3 of Work Package #3 (WP3), ROA Impact on the NAS. The purpose of the overall work package was to determine if there are any serious issues that would prevent or prohibit ROA's flying in the NAS on a routine basis, and if so, what actions should be taken to address them. The purpose of Task #3 was to look at this problem from the perspective of data modeling and sharing.

  14. Ultra-broadband GaInNAs semiconductor optical amplifier incorporating N compositional fluctuations for the next generation passive optical network

    NASA Astrophysics Data System (ADS)

    Sun, Xiao; Chang, Qingjiang

    2015-01-01

    Compositional fluctuations of the N in GaInNAs results in QD-like fluctuations in the conduction band minimum. The GaInNAs SOA gain is significantly broadened by adding the gain of both QW and QD-like fluctuations, providing a < 18 dB gain over 107 nm bandwidth cross both C and L bands in NG-PON2 applications.

  15. The CSM testbed software system: A development environment for structural analysis methods on the NAS CRAY-2

    NASA Technical Reports Server (NTRS)

    Gillian, Ronnie E.; Lotts, Christine G.

    1988-01-01

    The Computational Structural Mechanics (CSM) Activity at Langley Research Center is developing methods for structural analysis on modern computers. To facilitate that research effort, an applications development environment has been constructed to insulate the researcher from the many computer operating systems of a widely distributed computer network. The CSM Testbed development system was ported to the Numerical Aerodynamic Simulator (NAS) Cray-2, at the Ames Research Center, to provide a high end computational capability. This paper describes the implementation experiences, the resulting capability, and the future directions for the Testbed on supercomputers.

  16. 1.55 ?m GaInNAs resonant-cavity-enhanced photodetector grown on GaAs

    NASA Astrophysics Data System (ADS)

    Han, Q.; Yang, X. H.; Niu, Z. C.; Ni, H. Q.; Xu, Y. Q.; Zhang, S. Y.; Du, Y.; Peng, L. H.; Zhao, H.; Tong, C. Z.; Wu, R. H.; Wang, Q. M.

    2005-09-01

    We report the design, growth, fabrication, and characterization of a GaAs-based resonant-cavity-enhanced (RCE) GaInNAs photodetector operating at 1.55?m. The structure of the device was designed using a transfer-matrix method (TMM). By optimizing the molecular-beam epitaxy growth conditions, six GaInNAs quantum wells were used as the absorption layers. Twenty-five (25)- and 9-pair GaAs /AlAs-distributed Bragg reflectors were grown as the bottom and top mirrors. At 1.55?m, a quantum efficiency of 33% with a full width at half maximum of 10nm was obtained. The dark current density was 3×10-7A/cm2 at a bias of 0V and 4.3×10-5A/cm2 at a reverse bias of 5V. The primary time response measurement shows that the device has a rise time of less than 800ps.

  17. Cohort Profile: The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry).

    PubMed

    Gatz, Margaret; Harris, Jennifer R; Kaprio, Jaakko; McGue, Matt; Smith, Nicholas L; Snieder, Harold; Spiro, Avron; Butler, David A

    2015-06-01

    The National Academy of Sciences-National Research Council Twin Registry (NAS-NRC Twin Registry) is a comprehensive registry of White male twin pairs born in the USA between 1917 and 1927, both of the twins having served in the military. The purpose was medical research and ultimately improved clinical care. The cohort was assembled in the early 1960s with identification of approximately 16,000 twin pairs, review of service records, a brief mailed questionnaire assessing zygosity, and a health survey largely comparable to questionnaires used at that time with Scandinavian twin registries. Subsequent large-scale data collection occurred in 1974, 1985 and 1998, repeating the health survey and including information on education, employment history and earnings. Self-reported data have been supplemented with mortality, disability and medical data through record linkage. Potential collaborators should access the study website [http://www.iom.edu/Activities/Veterans/TwinsStudy.aspx] or e-mail the Medical Follow-up Agency at [Twins@nas.edu]. Questionnaire data are being prepared for future archiving with the National Archive of Computerized Data on Aging (NACDA) at the Inter-University Consortium for Political and Social Research (ICPSR), University of Michigan, MI. PMID:25183748

  18. Probing of the Nature of Carrier Recombination in GaInNAs epilayers using Optical Spin Injection

    NASA Astrophysics Data System (ADS)

    Tsai, Yutsung; Barman, Biplob; Scrace, Thomas; Petrou, Athos; Fukuda, M.; Sellers, I. R.; Khalfioui, M. A.

    2013-03-01

    Optical pumping experiments have been performed on as-grown and p-type MBE grown GaInNAs epilayers. The PL peak of the nominally undoped as-grown sample exhibits the characteristic S-shaped dependence of dilute nitride material for T < 60 K. This is associated with carrier recombination via localized states at low temperatures. The reflectance spectra on the other hand map the band-to-band free carrier transition, displaying a Varshni-type behavior. In the p-type material the S-dependence of the PL disappears, and the PL peak coincides with the reflectance spectrum at all temperatures. This indicates band-to-band, rather than localized exciton recombination, in the p-type GaInNAs at all temperatures. This picture was verified by optical pumping experiments. In the undoped sample a large degree of circular polarization was evident only at T > 60 K: below 60 K the polarization is small, and coincident with the reflectance peak. In the p-type samples, on the other hand, non-zero circular polarization, whose maximum matches the peak PL energy, was evident at all temperatures. Research supported by Amethyst Research Inc. through the State of Oklahoma, ONAP program.

  19. Simulation and optimization of current and lattice matching double-junction GaNAsP/Si solar cells

    NASA Astrophysics Data System (ADS)

    Nacer, S.; Aissat, A.

    2016-01-01

    This paper deals with theoretical investigation of the performance of current and lattice matched GaNxAsyP1-x-y/Si double-junction solar cells. The nitrogen and arsenic concentrations ensuring lattice matching to Si are determined. The band gap of GaNAsP is calculated using the band anti-crossing model. Calculations were performed under 1-sun AM1.5 using the one diode ideal model. Impact of minor carrier lifetime and surface recombination in the top sub-cell on the cell performances is analyzed. Optimum compositions of the top sub-cell have been identified (x = 4.5%, y = 11.5% and Eg = 1.68 eV). The simulation results predict, for the optimized GaNAsP/Si double-junction solar cell, a short circuit current Jsc = 20 mA/cm2, an open circuit voltage Voc = 1.95 V, and a conversion efficiency η = 37.5%.

  20. Remotely Operated Aircraft (ROA) Impact on the National Airspace System (NAS) Work Package, 2005: Composite Report on FAA Flight Plan and Operational Evaluation Plan. Version 7.0

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The purpose of this document is to present the findings that resulted from a high-level analysis and evaluation of the following documents: (1) The OEP (Operational Evolution Plan) Version 7 -- a 10-year plan for operational improvements to increase capacity and efficiency in U.S. air travel and transport and other use of domestic airspace. The OEP is the FAA commitment to operational improvements. It is outcome driven, with clear lines of accountability within FAA organizations. The OEP concentrates on operational solutions and integrates safety, certification, procedures, staffing, equipment, avionics and research; (2) The Draft Flight Plan 2006 through 2010 -- a multi-year strategic effort, setting a course for the FAA through 2001, to provide the safest and most efficient air transportation system in the world; (3) The NAS System Architecture Version 5 -- a blueprint for modernizing the NAS and improving NAS services and capabilities through the year 2015; and (4) The NAS-SR-1000 System Requirements Specification (NASSRS) -- a compilation of requirements which describe the operational capabilities for the NAS. The analysis is particularly focused on examining the documents for relevance to existing and/or planned future UAV operations. The evaluation specifically focuses on potential factors that could materially affect the development of a commercial ROA industry, such as: (1) Design limitations of the CNS/ATM system, (2) Human limitations, The information presented was taken from program specifications or program office lead personnel.

  1. Study of nitrogen incorporation into GaInNAs: The role of growth temperature in molecular beam epitaxy

    SciTech Connect

    Korpijaervi, V.-M.; Aho, A.; Tukiainen, A.; Laakso, A.; Guina, M.; Laukkanen, P.; Tuominen, M.

    2012-07-15

    GaInNAs has an important impact on developing GaAs-based optoelectronics and multijunction solar cells, but the complex nature of the nitrogen incorporation into GaInAs is still not fully understood. By combining x-ray diffraction, photoluminescence, reflection high-energy electron diffraction, and photoelectron spectroscopy measurements, we show that nitrogen incorporation is enhanced with increasing growth temperature in the range of 300-450 Degree-Sign C. We study the growth front and show that the surface reconstruction is (1 Multiplication-Sign 3) regardless of growth temperature in this range. The enhanced nitrogen incorporation can be modeled as a thermally activated process with activation energy of about 0.1 eV.

  2. Modelling of the effects of conduction band fluctuations caused by nitrogen clustering in GaInNAs materials

    NASA Astrophysics Data System (ADS)

    Sun, Xiao; Rorison, Judy M.

    2010-12-01

    It has been observed experimentally that the band edge photoluminescence of GaInNAs Quantum well (QW) materials is broadened resulting from band-tailing, localised states or conduction band edge fluctuations. In this paper we develop a model for N compositional fluctuations causing conduction band edge fluctuations which localise the electrons into the resulting quantum dots (QDs). The electron dynamics in the QDs and QW states are examined using a rate equation approach and the carrier populations presented as a function of barrier height and temperature. This mechanism could lead to broad gain in GaInAsN QW structures which could be useful for broad band SOAs for optical communications.

  3. High-power temperature-stable GaInNAs distributed Bragg reflector laser emitting at 1180??nm.

    PubMed

    Korpijärvi, Ville-Markus; Viheriälä, Jukka; Koskinen, Mervi; Aho, Antti T; Guina, Mircea

    2016-02-15

    We report a single-mode 1180 nm distributed Bragg reflector (DBR) laser diode with a high output power of 340 mW. For the fabrication, we employed novel nanoimprint lithography that ensures cost-effective, large-area, conformal patterning and does not require regrowth. The output characteristics exhibited outstanding temperature insensitivity with a power drop of only 30% for an increase of the mount temperature from 20°C to 80°C. The high temperature stability was achieved by using GaInNAs/GaAs quantum wells (QWs), which exhibit improved carrier confinement compared to standard InGaAs/GaAs QWs. The corresponding characteristic temperatures were T0=110??K and T1=160??K. Moreover, we used a large detuning between the peak wavelength of the material gain at room temperature and the lasing wavelength determined by the DBR. In addition to good temperature characteristics, GaInNAs/GaAs QWs exhibit relatively low lattice strain with direct impact on improving the lifetime of laser diodes at this challenging wavelength range. The single-mode laser emission could be tuned by changing the mount temperature (0.1 nm/°C) or the drive current (0.5 pm/mA). The laser showed no degradation in a room-temperature lifetime test at 900 mA drive current. These compact and efficient 1180 nm laser diodes are instrumental for the development of compact frequency-doubled yellow-orange lasers, which have important applications in medicine and spectroscopy. PMID:26872156

  4. Incorporation model of N into GaInNAs alloys grown by radio-frequency plasma-assisted molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Aho, A.; Korpijärvi, V.-M.; Tukiainen, A.; Puustinen, J.; Guina, M.

    2014-12-01

    We present a Maxwell-Boltzmann electron energy distribution based model for the incorporation rate of nitrogen into GaInNAs grown by molecular beam epitaxy (MBE) using a radio frequency plasma source. Nitrogen concentration is predicted as a function of radio-frequency system primary resistance, N flow, and RF power, and group III growth rate. The semi-empirical model is shown to be repeatable with a maximum error of 6%. The model was validated for two different MBE systems by growing GaInNAs on GaAs(100) with variable nitrogen composition of 0%-6%.

  5. Incorporation model of N into GaInNAs alloys grown by radio-frequency plasma-assisted molecular beam epitaxy

    SciTech Connect

    Aho, A.; Korpijärvi, V.-M.; Tukiainen, A.; Puustinen, J.; Guina, M.

    2014-12-07

    We present a Maxwell-Boltzmann electron energy distribution based model for the incorporation rate of nitrogen into GaInNAs grown by molecular beam epitaxy (MBE) using a radio frequency plasma source. Nitrogen concentration is predicted as a function of radio-frequency system primary resistance, N flow, and RF power, and group III growth rate. The semi-empirical model is shown to be repeatable with a maximum error of 6%. The model was validated for two different MBE systems by growing GaInNAs on GaAs(100) with variable nitrogen composition of 0%–6%.

  6. Effects of insertion of strain-engineering Ga(In)NAs layers on optical properties of InAs/GaAs quantum dots for high-efficiency solar cells

    NASA Astrophysics Data System (ADS)

    Pavelescu, Emil-Mihai; Polojärvi, Ville; Schramm, Andreas; Tukiainen, Antti; Aho, Arto; Zhang, Wenxin; Puustinen, Janne; Salmi, Joel; Guina, Mircea

    2016-02-01

    We report study on stacked InAs/GaNAs quantum dots heterostructures with dilute nitride GaInNAs strain mediating layers embedded in GaAs p-i-n solar cell structure. The insertion of GaInNAs strain mediating layers in the vicinity of the strain compensated InAs/GaNAs quantum dots heterostructures enhances their surface density, improves and significantly red shifts their light emission. Embedding a stack of the strain-mediated InAs/GaInNAs/GaNAs quantum dots in the i region of a GaAs p-i-n solar cell leads also to a red shift of the absorption edge of the solar cells and improves the solar cell photogenerated currents at longer wavelengths beyond 1200 nm.

  7. Effects of rapid thermal annealing conditions on GaInNAs band gap blueshift and photoluminescence intensity

    SciTech Connect

    Liverini, V.; Rutz, A.; Keller, U.; Schoen, S.

    2006-06-01

    We have studied the effects of various conditions of rapid thermal annealing (RTA) on 10 nm GaInNAs/GaAs single quantum wells (SQWs) with fixed indium concentration and increasing nitrogen content to obtain photoluminescence (PL) in the telecom wavelength regime of 1.3 and 1.5 {mu}m. Specifically, we analyzed the results of annealing for a fixed short time but at different temperatures and for longer times at a fixed temperature. In all experiments, InGaAs SQWs with the same In concentration were used as references. For both RTA conditions, the well-known blueshift of the band gap energy and the PL intensity improvement show trends that reveal that these are unrelated effects. At high RTA temperatures the PL efficiency reaches a maximum and then drops independently of N content. On the contrary, the blueshift experiences a rapid increase up to 700 deg. C (strong blueshift regime) and it saturates above this temperature (weak blueshift regime). Both these blueshift regimes are related to the nitrogen content in the SQWs but in different ways. In the strong blueshift regime, we could obtain activation energy for the blueshift process in the range of 1.25 eV, which increases with N content. Analysis with high-resolution x-ray diffraction (HRXRD) shows that the blueshift experienced in this regime is not due to a stoichiometric change in the QW. In the weak blueshift regime, the blueshift, which is only partly due to In outdiffusion, saturates more slowly the higher the N content. Annealing at the same temperature (600 deg. C) for a longer time shows that the blueshift saturates earlier than the PL intensity and that samples with higher nitrogen experience a larger blueshift. Only a small In outdiffusion for annealing at high temperatures (>650 deg. C) and long duration was observed. However, this modest stoichiometric change does not explain the large blueshift experienced by the GaInNAs SQWs. We conclude that the mechanism responsible for the drastic blueshift after annealing is related to the N content in the QW, while the improvement in PL integrated intensity is uniquely related to the annealing conditions.

  8. Enhancement of photoluminescence from GaInNAsSb quantum wells upon annealing: improvement of material quality and carrier collection by the quantum well.

    PubMed

    Baranowski, M; Kudrawiec, R; Latkowska, M; Syperek, M; Misiewicz, J; Sarmiento, T; Harris, J S

    2013-02-13

    In this study we apply time resolved photoluminescence and contactless electroreflectance to study the carrier collection efficiency of a GaInNAsSb/GaAs quantum well (QW). We show that the enhancement of photoluminescence from GaInNAsSb quantum wells annealed at different temperatures originates not only from (i) the improvement of the optical quality of the GaInNAsSb material (i.e., removal of point defects, which are the source of nonradiative recombination) but it is also affected by (ii) the improvement of carrier collection by the QW region. The total PL efficiency is the product of these two factors, for which the optimal annealing temperatures are found to be ~700 °C and ~760 °C, respectively, whereas the optimal annealing temperature for the integrated PL intensity is found to be between the two temperatures and equals ~720 °C. We connect the variation of the carrier collection efficiency with the modification of the band bending conditions in the investigated structure due to the Fermi level shift in the GaInNAsSb layer after annealing. PMID:23306016

  9. Study of a 1 eV GaNAsSb photovoltaic cell grown on a silicon substrate

    SciTech Connect

    Tan, K. H.; Loke, W. K.; Wicaksono, S.; Li, D.; Leong, Y. R.; Yoon, S. F.; Sharma, P.; Milakovich, T.; Bulsara, M. T.; Fitzgerald, E. A.

    2014-03-10

    We report the performance of a 1 eV GaNAsSb photovoltaic cell grown on a Si substrate with a SiGe graded buffer grown using molecular beam epitaxy. For comparison, the performance of a similar 1 eV GaN{sub 0.018}As{sub 0.897}Sb{sub 0.085} photovoltaic cell grown on a GaAs substrate was also reported. Both devices were in situ annealed at 700 °C for 5 min, and a significant performance improvement over our previous result was observed. The device on the GaAs substrate showed a low open circuit voltage (V{sub OC}) of 0.42 V and a short circuit current density (J{sub SC}) of 23.4 mA/cm{sup 2} while the device on the Si substrate showed a V{sub OC} of 0.39 V and a J{sub SC} of 21.3 mA/cm{sup 2}. Both devices delivered a quantum efficiency of 50%–55% without any anti-reflection coating.

  10. An approach to high efficiencies using GaAs/GaInNAs multiple quantum well and superlattice solar cell

    NASA Astrophysics Data System (ADS)

    Courel, Maykel; Rimada, Julio C.; Hernández, Luis

    2012-09-01

    A new type of photovoltaic device where GaAs/GaInNAs multiple quantum wells (MQW) or superlattice (SL) are inserted in the i-region of a GaAs p-i-n solar cell (SC) is presented. The results suggest the device can reach record efficiencies for single-junction solar cells. A theoretical model is developed to study the performance of this device. The conversion efficiency as a function of wells width and depth is modeled for MQW solar cells. It is shown that the MQW solar cells reach high conversion efficiency values. A study of the SL solar cell viability is also presented. The conditions for resonant tunneling are established by the matrix transfer method for a superlattice with variable quantum wells width. The effective density of states and the absorption coefficient for SL structure are calculated in order to determinate the J-V characteristic. The influence of superlattice length on the conversion efficiency is researched, showing a better performance when width and cluster numbers are increased. The SL solar cell conversion efficiency is compared with the maximum conversion efficiency obtained for the MQW solar cell and shows an efficiency enhancement.

  11. Origin of radiative recombination and manifestations of localization effects in GaAs/GaNAs core/shell nanowires

    SciTech Connect

    Chen, S. L.; Filippov, S.; Chen, W. M.; Buyanova, I. A.; Ishikawa, Fumitaro

    2014-12-22

    Radiative carrier recombination processes in GaAs/GaNAs core/shell nanowires grown by molecular beam epitaxy on a Si substrate are systematically investigated by employing micro-photoluminescence (μ-PL) and μ-PL excitation (μ-PLE) measurements complemented by time-resolved PL spectroscopy. At low temperatures, alloy disorder is found to cause localization of photo-excited carriers leading to predominance of optical transitions from localized excitons (LE). Some of the local fluctuations in N composition are suggested to lead to strongly localized three-dimensional confining potential equivalent to that for quantum dots, based on the observation of sharp and discrete PL lines within the LE contour. The localization effects are found to have minor influence on PL spectra at room temperature due to thermal activation of the localized excitons to extended states. Under these conditions, photo-excited carrier lifetime is found to be governed by non-radiative recombination via surface states which is somewhat suppressed upon N incorporation.

  12. Utility experience with a 250-kW molten carbonate fuel cell cogeneration power plant at NAS Miramar, San Diego

    NASA Astrophysics Data System (ADS)

    Figueroa, R. A.; Otahal, J.

    This paper focuses on the strategy and experience of San Diego Gas and Electric with the development and demonstration of a proof of concept 250-kW internally manifolded heat exchanger (IMHEX®) carbonate fuel cell power plant. The plant was installed, commissioned, and operated by San Diego Gas and Electric (SDG&E) in a cogeneration mode at the Naval Air Station (NAS) at Miramar in San Diego. These activities were part of a collaborative effort between SDG&E and M-C Power's Program team (IMHEX® Team). The IMHEX® Team consists of M-C Power, Bechtel Engineering, Stewart and Stevenson, and the Institute of Gas Technology (IGT). The technical aspects of the plant's commissioning and operation were addressed by my colleague, J. Otahal, in a poster presentation. Our activities in carbonate fuel cell development are unique because of the level of involvement by an investor-owned utility in the development, engineering, installation, operation and maintenance of a fuel cell demonstration plant. The following topics are discussed in this paper: (i) SDG&E's involvement in the development of molten carbonate fuel cell (MCFC) technology; (ii) the active role in engineering and specification of the IMHEX® MCFC demonstration plant; (iii) responsibility for installation, commissioning, and operation; (iv) utility role in technology development and application of MCFC in a restructured and competitive environment; (v) summary.

  13. The solution of linear systems of equations with a structural analysis code on the NAS CRAY-2

    NASA Technical Reports Server (NTRS)

    Poole, Eugene L.; Overman, Andrea L.

    1988-01-01

    Two methods for solving linear systems of equations on the NAS Cray-2 are described. One is a direct method; the other is an iterative method. Both methods exploit the architecture of the Cray-2, particularly the vectorization, and are aimed at structural analysis applications. To demonstrate and evaluate the methods, they were installed in a finite element structural analysis code denoted the Computational Structural Mechanics (CSM) Testbed. A description of the techniques used to integrate the two solvers into the Testbed is given. Storage schemes, memory requirements, operation counts, and reformatting procedures are discussed. Finally, results from the new methods are compared with results from the initial Testbed sparse Choleski equation solver for three structural analysis problems. The new direct solvers described achieve the highest computational rates of the methods compared. The new iterative methods are not able to achieve as high computation rates as the vectorized direct solvers but are best for well conditioned problems which require fewer iterations to converge to the solution.

  14. The NAS parallel benchmarks

    NASA Technical Reports Server (NTRS)

    Bailey, David (Editor); Barton, John (Editor); Lasinski, Thomas (Editor); Simon, Horst (Editor)

    1993-01-01

    A new set of benchmarks was developed for the performance evaluation of highly parallel supercomputers. These benchmarks consist of a set of kernels, the 'Parallel Kernels,' and a simulated application benchmark. Together they mimic the computation and data movement characteristics of large scale computational fluid dynamics (CFD) applications. The principal distinguishing feature of these benchmarks is their 'pencil and paper' specification - all details of these benchmarks are specified only algorithmically. In this way many of the difficulties associated with conventional benchmarking approaches on highly parallel systems are avoided.

  15. Defect Formation and Strain Relaxation in graded GaPAs/GaAs, GaNAs/GaAs and GaInNAs/Ge Buffer Systems for high-efficiency Solar Cells

    NASA Astrophysics Data System (ADS)

    Schöne, J.; Spiecker, E.; Dimroth, F.; Bett, A. W.; Jäger, W.

    2013-11-01

    Transmission electron microscopy of cross-section specimens and high-resolution X-ray diffraction analyses have been applied to investigate the formation of defects and the relaxation of layer strain in step-graded GaPxAs1-x and GaNyAs1-y buffer layer systems grown by metal-organic vapour phase epitaxy on GaAs (001) substrates with 6° miscut towards (111)A. The investigations have been complemented by characterization of the layer surfaces employing optical microscopy. The comparison of the different buffer concepts reveals characteristic differences in the formation of defects and in the relaxation of tensile layer strain. For GaPAs layers dislocations and microtwins form, releasing the major part of the tensile misfit strain. In contrast, for GaNAs dislocations and microtwins are largely absent, at least in the upper part of the buffer structure, and microcracks are generated. Consequently, during subsequent growth of layers with tensile strain, strain relaxation and defect formation can be effectively hindered by introducing intermediate GaNyAs1-y layers with concentrations y > 2 % into a GaAs1-xPx buffer structure [1]. A similar concept can be used for layer systems with compressive strain, however, modified by using layers of differing alloy composition. The use of dilute nitride layers appears to offer a new concept for engineering defect distributions and layer strain in lattice-mismatched compound semiconductor layer structures. Such concepts are of particular interest not only but especially also for applications in high-efficiency III-V solar cells.

  16. Molecular beam epitaxy of GaNAs alloys with high As content for potential photoanode applications in hydrogen production

    SciTech Connect

    Novikov, S. V.; Staddon, C. R.; Foxon, C. T.; Yu, K. M.; Broesler, R.; Hawkridge, M.; Liliental-Weber, Z.; Walukiewicz, W.; Denlinger, J.; Demchenko, I.

    2009-10-06

    The authors have succeeded in growing GaN1?xAsx alloys over a large composition range (0 < x < 0.8) by plasma-assisted molecular beam epitaxy. The enhanced incorporation of As was achieved by growing the films with high As{sub 2} flux at low (as low as 100 C) growth temperatures, which is much below the normal GaN growth temperature range. Using x-ray and transmission electron microscopy, they found that the GaNAs alloys with high As content x > 0.17 are amorphous. Optical absorption measurements together with x-ray absorption and emission spectroscopy results reveal a continuous gradual decrease in band gap from -3.4 to < 1 eV with increasing As content. The energy gap reaches its minimum of -0.8 eV at x - 0.8. The composition dependence of the band gap of the crystalline GaN{sub 1?x}As{sub x} alloys follows the prediction of the band anticrossing model (BAC). However, our measured band gap of amorphous GaN{sub 1?x}As{sub x} with 0.3 < x < 0.8 are larger than that predicted by BAC. The results seem to indicate that for this composition range the amorphous GaN{sub 1?x}As{sub x} alloys have short-range ordering that resembles random crystalline GaN{sub 1?x}As{sub x} alloys. They have demonstrated the possibility of the growth of amorphous GaN{sub 1?x}As{sub x} layers with variable As content on glass substrates

  17. GaInNAs/Ge (1.10/0.67?eV) double-junction solar cell grown by metalorganic chemical vapor deposition for high efficiency four-junction solar cell application

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaobin; Chen, Bingzhen; Pan, Xu; Wang, Lei; Ma, Difei; Zhang, Yang; Yang, Cuibai; Wang, Zhiyong

    2015-12-01

    GaInNAs materials with narrow bandgaps of 1.10?eV have been grown on a Ge substrate by metalorganic chemical vapor deposition to fabricate GaInNAs/Ge (1.10/0.67?eV) double-junction solar cells. We have studied the photovoltaic characteristics and the external quantum efficiencies of the double-junction cells with various annealing conditions and different GaInNAs base layer thicknesses. The best external quantum efficiency is obtained from the double-junction cell with a 1170?nm thick GaInNAs base layer annealed at 675 °C for 30?min. Under AM1.5G illumination, the best double-junction cell has a short circuit current density (J SC) as 23.63 mA cm?2, which is dominated by the J SC of the GaInNAs subcell.

  18. A room temperature Na/S battery using a β″ alumina solid electrolyte separator, tetraethylene glycol dimethyl ether electrolyte, and a S/C composite cathode

    NASA Astrophysics Data System (ADS)

    Kim, Icpyo; Park, Jin-Young; Kim, Chang Hyeon; Park, Jin-Woo; Ahn, Jae-Pyoung; Ahn, Jou-Hyeon; Kim, Ki-Won; Ahn, Hyo-Jun

    2016-01-01

    To realize a high-performance room temperature Na/S battery with an elemental sulfur cathode, it is important that sodium polysulfides stay within the cathode and that they have room enough to react freely. In this work, sodium polysulfides are confined to the cathode using a β″ alumina solid electrolyte separator and an optimal amount of tetraethylene glycol dimethyl ether (TEGDME) electrolyte. In addition, an activated carbon material, in the form of a sulfur/carbon (S/C) composite, with high surface area, porosity, and pore volume is employed in the cathode. The resulting Na/S battery shows a high first discharge capacity of 855 mAh g-1 and coulombic efficiency close to 100%, as well as stable cyclability, with a discharge capacity of 521 mAh g-1 at the 104th discharge.

  19. Weather Requirements and Procedures for Step 1: High Altitude Long Endurance (HALE) Unmanned Aircraft System (UAS) Flight Operations in the National Air Space (NAS)

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This cover sheet is for version 2 of the weather requirements document along with Appendix A. The purpose of the requirements document was to identify and to list the weather functional requirements needed to achieve the Access 5 vision of "operating High Altitude, Long Endurance (HALE) Unmanned Aircraft Systems (UAS) routinely, safely, and reliably in the National Airspace System (NAS) for Step 1." A discussion of the Federal Aviation Administration (FAA) references and related policies, procedures, and standards is provided as basis for the recommendations supported within this document. Additional procedures and reference documentation related to weather functional requirements is also provided for background. The functional requirements and related information are to be proposed to the FAA and various standards organizations for consideration and approval. The appendix was designed to show that sources of flight weather information are readily available to UAS pilots conducting missions in the NAS. All weather information for this presentation was obtained from the public internet.

  20. Unmanned Aircraft Systems (UAS) Integration in the National Airspace System (NAS) Project, UAS Control and Non-Payload Communication System Phase-1 Flight Test Results

    NASA Technical Reports Server (NTRS)

    Griner, James H.

    2014-01-01

    NASA's UAS Integration in the NAS project, has partnered with Rockwell Collins to develop a concept Control and Non-Payload Communication (CNPC) system prototype radio, operating on recently allocated UAS frequency spectrum bands. This prototype radio is being used to validate initial proposed performance requirements for UAS control communications. This presentation will give an overview of the current status of the prototype radio development, and results from phase 1 flight tests conducted during 2013.

  1. MOVPE growth studies of Ga(NAsP)/(BGa)(AsP) multi quantum well heterostructures (MQWH) for the monolithic integration of laser structures on (001) Si-substrates

    NASA Astrophysics Data System (ADS)

    Ludewig, P.; Reinhard, S.; Jandieri, K.; Wegele, T.; Beyer, A.; Tapfer, L.; Volz, K.; Stolz, W.

    2016-03-01

    High-quality, pseudomorphically strained Ga(NAsP)/(BGa)(AsP)-multiple quantum well heterostructures (MQWH) have been deposited on exactly oriented (001) Si-substrate by metal organic vapour phase epitaxy (MOVPE) in a wide temperature range between 525 °C and 700 °C. The individual atomic incorporation efficiencies, growth rates as well as nanoscale material properties have been clarified by applying detailed high-resolution X-ray diffraction (HR-XRD), photoluminescence (PL) spectroscopy and high-angle annular dark field (HAADF) scanning transmission electron microscopy (STEM) studies. An almost constant N-incorporation efficiency is obtained for a wide growth temperature range from 550 °C up to 650 °C. The P-incorporation is steadily increasing with increasing growth temperature reaching values at high temperatures in excess of the applied gas phase ratio. While the lower interface from the binary GaP- to the quaternary Ga(NAsP)-material system is very sharp, the upper interface is significantly rougher with a roughness scale of ±0.43 nm in quantum well thickness variation at a growth temperature of 525 °C. This roughness scale increases steadily with increasing growth temperature. No indication of any phase separation effects is detected in the Ga(NAsP)-material system even at the highest growth temperature of 700 °C. The obtained experimental results are briefly discussed with respect to the anticipated metastable character of the novel dilute-nitride Ga(NAsP)-material system grown lattice-matched to (001) Si-substrate.

  2. Identification of nitrogen- and host-related deep-level traps in n-type GaNAs and their evolution upon annealing

    SciTech Connect

    Gelczuk, Ł.; Henini, M.

    2014-07-07

    Deep level traps in as-grown and annealed n-GaNAs layers (doped with Si) of various nitrogen concentrations (N=0.2%, 0.4%, 0.8%, and 1.2%) were investigated by deep level transient spectroscopy. In addition, optical properties of GaNAs layers were studied by photoluminescence and contactless electroreflectance. The identification of N- and host-related traps has been performed on the basis of band gap diagram [Kudrawiec, Appl. Phys. Lett. 101, 082109 (2012)], which assumes that the activation energy of electron traps of the same microscopic nature decreases with the rise of nitrogen concentration in accordance with the N-related shift of the conduction band towards trap levels. The application of this diagram has allowed to investigate the evolution of donor traps in GaNAs upon annealing. In general, it was observed that the concentration of N- and host-related traps decreases after annealing and PL improves very significantly. However, it was also observed that some traps are generated due to annealing. It explains why the annealing conditions have to be carefully optimized for this material system.

  3. Designing of 1 eV GaNAs/GaInAs superlattice subcell in current-matched four-junction solar cell

    NASA Astrophysics Data System (ADS)

    Haixiao, Wang; Xinhe, Zheng; Xingyuan, Gan; Naiming, Wang; Hui, Yang

    2016-01-01

    A reasonably-thick GaNAs/GaInAs superlattice could be an option as a roughly 1 eV subcell to achieve high-efficiency multi-junction solar cells on a lattice-matched Ge substrate. A detailed consideration of a high-efficiency design for a GaInP/GaAs/1 eV/Ge device is presented. Calculations have been done for this structure to obtain the confined energies of the electrons and holes by utilizing the Kronig-Penney model, as well as the absorption coefficient and thereby the external quantum efficiency. The effect of well layers, GaNAs or GaInAs, on the absorption and photocurrent density under the AM 1.5 condition is discussed in order to realize a requirement of current matching in the four-junction solar cells. The management of these considerations implies the feasibility of the GaNAs/GaInAs superlattice subcell design to improve the overall conversion efficiency of lattice matched GaInP/GaAs/1 eV/Ge cells. Project supported by the National Natural Science Foundation of China (No. 61274134) and the International Cooperation Program of Suzhou, China (No. SH201215).

  4. Development and manufacturing of panoramic Stokes polarimeter using the polarization films in the Main Astronomical Observatory of NAS of Ukraine

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.; Ivanov, Yu. S.; Syniavskyi, I. I.; Sergeev, A. V.

    2015-08-01

    In the Main Astronomical Observatory of NAS of Ukraine is proposed and implemented the concept of the imaging Stokes polarimeter [1-5]. This device allows carrying out measurements of the four Stokes vector components at the same time, in a wide field, and without any restrictions on the relative aperture of the optical system. Its scheme is developed so that only by turning wheel with replaceable elements, photopolarimeter could be transformed into a low resolution spectropolarimeter. The device has four film's polarizers with positional angles 0°, 45°, 90°, 135°. The device uses a system of special deflecting prisms in each channel. These prisms were achromatizing in the spectral range of 420-850 nm [2], the distortion of the polarimeter optical system is less than 0.65%. In manufacturing version of spectropolarimeter provided for the possibility of using working on passing the diffraction grating with a frequency up to 100 lines/mm. Has begun the laboratory testing of instrument. References. 1. Sinyavskii I.I., Ivanov Yu. S., Vidmachenko Anatoliy P., Karpov N.V. Panoramic Stokes-polarimeter // Ecological bulettin of research centers of the Black Sea Economic Cooperation. - 2013. - V. 3, No 4. - P. 123-127. 2. Sinyavskii I. I., Ivanov Yu. S., Vil'machenko A. P. Concept of the construction, of the optical setup of a panoramic Stokes polarimeter for small telescopes // Journal of Optical Technology. - 2013. - V. 80, Issue 9. - P. 545-548. 3. Vidmachenko A. P., Ivanov Yu. S., Morozhenko A. V., Nevodovsky E. P., Syniavskyi I. I., Sosonkin M. G. Spectropolarimeter of ground-based accompanying for the space experiment "Planetary Monitoring" // Kosmichna Nauka i Tekhnologiya. - 2007. - V. 13, No. 1, p. 63 - 70. 4. Yatskiv Ya. S., Vidmachenko A. P., Morozhenko A. V., Sosonkin M. G., Ivanov Yu. S., Syniavskyi I. I. Spectropolarimetric device for overatmospheric investigations of Solar System bodies // Kosmichna Nauka i Tekhnologiya. - 2008. - V. 14, No. 2. - P. 56-67. 5. Yatskiv Ya. S., Vidmachenk o A. P., Morozhenko A. V., Sosonkin M. G., Ivanov Yu. S., Sinyavskiy I. I. Spectropolarimetric devices for extraterrestrial investigation of the Solar system bodies // 10 Ukrainian Conference on Space Research with International Participation. August 30-September 4, 2010. The program and abstracts. Yevpatoria, Ukraine. P. 81.

  5. A estabilidade dos PAHS em função da energia da radiação interestelar nas faixas UV e raios-X

    NASA Astrophysics Data System (ADS)

    Pinotti, R.; Costa, R. K.; Boechat-Roberty, H. M.; Lago, A.; Souza, G. B.

    2003-08-01

    A nebulosa CRL 618, uma proto-nebulosa planetária cuja nuvem molecular espessa envolve uma estrela B0, contém uma grande quantidade de C2H2 e CH4. Estas moléculas são consideradas os tijolos da criação de grandes moléculas carbonadas como os Hidrocarbonetos Policíclicos Aromáticos (PAHs). Esta nebulosa, por estar exposta a intensos campos de UV e Raios-X, é uma região de fotodissociação molecular que propicia a formação de novas moléculas, confirmada pela presença de C4H2 e C6H6 (Benzeno), que é a unidade básica dos PAHs. Atribui-se a esta família de moléculas orgânicas duas propriedades fundamentais, a resistência para sobreviver ao campo de radiação UV interestelar e a geração das bandas de emissão não identificadas (UIR) observadas no infravermelho. No entanto, alguns autores questionam a resistência dos PAHs ao campo de radiação UV interestelar. Empregando a técnica de Espectrometria de Massas por Tempo de Vôo, no modo de coincidência fotoelétron-fotoíon, estudamos a ionização e fragmentação das seguintes moléculas: Benzeno, Benzeno deuterado, Naftaleno, Antraceno e Fenantreno. Utilizamos uma fonte de Hélio monocromática em 21,21 eV (584,5 Å) e a radiação Síncroton do Laboratório Nacional de Luz Síncroton (LNLS) em diferentes energias nas proximidades da borda do C 1s ( 290 eV). Comprovamos a estabilidade dos PAHs sob ação de UV (21,21 eV), onde eles apresentam um baixo nível de fotodissociação, produzindo fragmentos ionizados com rendimento total na ordem de 5 por cento em relação ao íon molecular pai. Entretanto, em altas energias, na faixa de Raios-X, a quebra destas moléculas torna-se mais intensa, com a produção de muitos fragmentos. Como uma das rotas de fragmentação do Naftaleno é [(C10H8) = > (C6H6+) + (C4H2) + (e-)], e como temos as evidências observacionais da existência do C4H2 e C6H6 na nebulosa CRL 618, sugerimos que este ambiente também possui o Naftaleno.

  6. NOD promoter-controlled AtIRT1 expression functions synergistically with NAS and FERRITIN genes to increase iron in rice grains.

    PubMed

    Boonyaves, Kulaporn; Gruissem, Wilhelm; Bhullar, Navreet K

    2016-02-01

    Rice is a staple food for over half of the world's population, but it contains only low amounts of bioavailable micronutrients for human nutrition. Consequently, micronutrient deficiency is a widespread health problem among people who depend primarily on rice as their staple food. Iron deficiency anemia is one of the most serious forms of malnutrition. Biofortification of rice grains for increased iron content is an effective strategy to reduce iron deficiency. Unlike other grass species, rice takes up iron as Fe(II) via the IRON REGULATED TRANSPORTER (IRT) in addition to Fe(III)-phytosiderophore chelates. We expressed Arabidopsis IRT1 (AtIRT1) under control of the Medicago sativa EARLY NODULIN 12B promoter in our previously developed high-iron NFP rice lines expressing NICOTIANAMINE SYNTHASE (AtNAS1) and FERRITIN. Transgenic rice lines expressing AtIRT1 alone had significant increases in iron and combined with NAS and FERRITIN increased iron to 9.6 µg/g DW in the polished grains that is 2.2-fold higher as compared to NFP lines. The grains of AtIRT1 lines also accumulated more copper and zinc but not manganese. Our results demonstrate that the concerted expression of AtIRT1, AtNAS1 and PvFERRITIN synergistically increases iron in both polished and unpolished rice grains. AtIRT1 is therefore a valuable transporter for iron biofortification programs when used in combination with other genes encoding iron transporters and/or storage proteins. PMID:26560141

  7. Optical properties of multi-stacked InGaAs/GaNAs quantum dot solar cell fabricated on GaAs (311)B substrate

    SciTech Connect

    Shoji, Yasushi; Akimoto, Katsuhiro; Okada, Yoshitaka

    2012-09-15

    Quantum dot solar cells (QDSCs) comprised of 10 stacked pairs of strain-compensated InGaAs/GaNAs QD structure have been fabricated by atomic hydrogen-assisted molecular beam epitaxy. A homogeneous and high-density QD array structure with improved in-plane ordering and total density of {approx}10{sup 12} cm{sup -2} has been achieved on GaAs (311)B grown at 460 Degree-Sign C after stacking. The external quantum efficiency (EQE) of InGaAs/GaNAs QDSC increases in the longer wavelength range due to additive contribution from QD layers inserted in the intrinsic region. The short-circuit current density measured for QDSC is 17.2 mA/cm{sup 2} compared to 14.8 mA/cm{sup 2} of GaAs reference cell. Further, an increase in EQE due to photocurrent production by 2-step photon absorption has been observed at room temperature though it is still small at around 0.1%.

  8. p- to n-type conductivity transition in 1.0 eV GaInNAs solar cells controlled by the V/III ratio

    SciTech Connect

    Langer, Fabian Perl, Svenja; Kamp, Martin; Höfling, Sven

    2015-02-09

    In this work, we report a p- to n-type conductivity transition of GaInNAs (1.0 eV bandgap) layers in p-i-n dilute nitride solar cells continuously controlled by the V/III ratio during growth. Near the transition region, we were able to produce GaInNAs layers with very low effective electrically active doping concentrations resulting in wide depleted areas. We obtained internal quantum efficiencies (IQEs) up to 85% at 0.2 eV above the bandgap. However, the high IQE comes along with an increased dark current density resulting in a decreased open circuit voltage of about 0.2 V. This indicates the formation of non-radiant defect centers related to the p-type to n-type transition. Rapid-thermal annealing of the solar cells on the one hand helps to anneal some of these defects but on the other hand increases the effective doping concentrations.

  9. [Various ecological problems related to mining and processing of serpentine. Evaluation of non-occupational exposure of the population of Nasławice to fibrous mineral dust].

    PubMed

    Woźniak, H; Wiecek, E; Dobrucka, D; Pelc, W; Bielichowska-Cybula, G; Król, M; Opalska, B

    1992-01-01

    Non-occupational exposure of the population living in the vicinity of the serpentine mining and processing mill in Nasławice was assessed. The evaluation was based on the phase analysis and determination of respirable mineral fibres content in the samples of dust fall and soil in the fields nearby the mine, as well as on the in-door and out-door measurements of airborne fibres concentration. All soil samples contained antigorite--a mineral the structure of which is close to that of chrysotile asbestos add exhibiting high biological aggressiveness. The respirable mineral fibres content in the dust fall-out and in the soil ranged from 98,000 to 480,000 per 1 mg and from 48,000 to 122,000 per 1 mg, respectively, whereas the airborne concentrations were from 2 to 1540 fibres/l (outdoor) and from 4 to 7 fibres/l (indoor). The fall of dust in the years 1989-1990, recorded at all measuring points, exceeded 200,000 kg/km2 yearly (admissible value). The airborne concentrations of respirable mineral fibres were also higher than the admissible value (1 fibre/l of the air). The results obtained indicate that the exposure of the population in Nasławice to mineral fibrous dusts has significantly exceeded to maximum admissible concentrations established for non-occupational exposure. PMID:1328808

  10. População estelar jovem em galáxias irregulares próximas

    NASA Astrophysics Data System (ADS)

    Guimarães, T. A.; Telles, E.

    2003-08-01

    A análise do conteúdo estelar de galáxias próximas através da fotometria das suas estrelas resolvidas nos fornece informações importantes sobre a história de formação estelar e os processos de formação estelar em galáxias, que estão diretamente ligados ao estudo de evolução de galáxias. Quando nenhuma estrela puder ser resolvida o método mais poderoso consiste na análise do conteúdo estelar integrado das galáxias através das suas cores integradas em conjunto com informação espectroscópica que combinados com modelos de síntese evolutiva podem restringir simultaneamente a função de massa inicial (IMF) e a taxa de formação estelar (SFR). Nesse contexto, galáxias do tipo tardio, em particular, irregulares, são relevantes por várias razões: elas são objetos relativamente simples, com alta atividade de formação estelar e são objetos relativamente jovens (geralmente apresentam baixas abundâncias de elementos pesados e grande quantidade de gás). Apresentamos uma análise fotométrica de uma amostra de 7 galáxias do tipo tardio do universo local (NGC 2366, NGC 4395, NGC 4656, NGC 4214, NGC 4236, HOII, IC2574) que foram observadas com uma boa resolução espacial nas bandas B, V e R no telescópio Isaac Newton de 2.5m de Roque de los Muchachos nas Ilhas Canárias, Espanha. A distribuição espacial da população estelar jovem dessas galáxias é discutida sobre os pontos de vista dos íindices de cor integrados e dos seus diagramas cor magnitude, que comparados com isócronas teóricas, nos fornecem informações sobre os eventos de formação estelar, como por exemplo, indicações sobre a idade dos mesmos. As principais conclusões do trabalho podem ser resumidas em: (i) As galáxias irregulares possuem formação estelar recente (FE) espalhada ocorrendo nos últimos 50 Manos; (ii) A formação estelar em galáxias irregulares não é auto-propagante em escalas globais ( > 100 pc) ; (iii) A FE pode ser auto-regulável em escalas espaciais de poucas dezenas de parsec; (iv) As galáxias irregulares sofreram um evento principal de FE há 1010 anos atrás, o que implica que houve um momento na evolução do universo onde a maior parte das estrelas se formaram em galáxias.

  11. Optimal Blast Condition for the Inner Surface of Mass Produced NAS Battery Cylindrical Aluminum Cell Containers as Pretreatment of Thermal Spraying

    NASA Astrophysics Data System (ADS)

    Ando, Takashi; Harada, Yoshio

    The relationship between roughness caused by blasting and adhesion of spray coatings on aluminum container substrates was studied through various experiments as part of measures for improving the adhesion of the 75mass%Cr-Fe alloy plasma spray coating for sulfi dation corrosion resistance, which is applied on the inner surface of cylindrical Al containers of high-temperature type NAS batteries. Surface roughness of ?mRa2.8 - 7.3 was acquired by using Al2O3 particle size #100 (212 - 75?m) to #46 (600 - 250?m) grit. In order to achieve uniform roughness and a clean surface, a combination of blasting when the nozzle was being inserted from the top of the container, and air blowing when the nozzle was being removed was done. It was determined that when Al2O3 particles of size #100 grit was used, a good anchoring shape was formed throughout with a roughened surface of ?mRa 2.8. When the internal surface of 3000 Al cylindrical containers were continually blasted using particle size #100 grit, the initial surface roughness of ?mRa3.7 - 3.9 only deteriorated to about ?mRa2.6. A 75mass%Cr-Fe alloy spray coating was applied to the Al cylindrical containers that were roughened using particle size #100 grit. This coating showed cracks by a bending test, but no peeling occurred. This coating was examined by a tensile strength test and showed good adhesion at 64 - 66 MPa. Through experiments, it was proven that spray coatings formed on the Al cylindrical containers after receiving optimal blasting with particle size #100 grit had good adhesion and corrosion resistance after being used for NAS batteries that stored electrical power for about nine years.

  12. Reliability and Validity of the Novaco Anger Scale and Provocation Inventory (NAS-PI) and State-Trait Anger Expression Inventory-2 (STAXI-2) in Hispanic and Non-Hispanic White Student Samples

    ERIC Educational Resources Information Center

    Culhane, Scott E.; Morera, Osvaldo F.

    2010-01-01

    This project tested the State-Trait Anger Expression Inventory-2 (STAXI-2) and the Novaco Anger Scale-Provocation Inventory (NAS-PI) in a sample of U.S. Hispanic (n = 257) and U.S. non-Hispanic White (n = 246) undergraduate students. Internal consistency, subscale correlations, convergent validity with the Multidimensional Anger Inventory (MAI),…

  13. DNA microarray-based solid-phase PCR on copoly (DMA-NAS-MAPS) silicon coated slides: An example of relevant clinical application.

    PubMed

    Damin, Francesco; Galbiati, Silvia; Ferrari, Maurizio; Chiari, Marcella

    2016-04-15

    In a previous study we developed a highly sensitive DNA microarray for the detection of common KRAS oncogenic mutations, which has been proven to be highly specific in assigning the correct genotype without any enrichment strategy even in the presence of minority mutated alleles. However, in this approach, the need of a spotter for the deposition of the purified PCR products on the substrates and the purification step of the conventional PCR are serious drawbacks. To overcome these limitations we have introduced the solid-phase polymerase chain reaction (SP-PCR) to form the array of PCR products starting from the oligonucleotide primers. This work was possible thanks to the great thermal stability of the copoly (DMA-NAS-MAPS) coating which withstands PCR thermal cycling temperatures. As an example of the application of this platform we performed the analysis of six common mutations in the codon 12 of KRAS gene (G12A, G12C, G12D, G12R, G12S, and G12V). In conclusion solid-phase PCR, combined with dual-color hybridization, allows mutation analysis in a shorter time span and is more suitable for automation. PMID:26655175

  14. Pratt and Whitney/Boeing Engine Validation of Noise Reduction Concepts: Final Report for NASA Contract NAS3-97144, Phase 1

    NASA Technical Reports Server (NTRS)

    Mathews, Douglas; Bock, Larry A.; Bielak, Gerald W.; Dougherty, R. P.; Premo, John W.; Scharpf, Dan F.; Yu, Jia

    2014-01-01

    Major airports in the world's air transportation systems face a serious problem in providing greater capacity to meet the ever increasing demands of air travel. This problem could be relieved if airports are allowed to increase their operating time, now restricted by curfews and by relaxing present limits on takeoffs and landings. The key operational issue in extending the present curfews is noise. In response to these increasing restrictive noise regulations, NASA has launched a program to validate through engine testing, noise reduction concepts and technologies that have evolved from the Advanced Subsonic Technologies (AST) Noise Reduction Program. The goal of this AST program was to develop and validate technology that reduces engine noise and improves nacelle suppression effectiveness relative to 1992 technology. Contract NAS3-97144 titled "Engine Validation of Noise Reduction Concepts" (EVNRC) was awarded to P&W on August 12, 1997 to conduct full scale noise reduction tests in two Phases on a PW4098 engine. The following Section 1.2 provides a brief description of the overall program. The remainder of this report provides a detailed documentation of Phase I of the program.

  15. Investigation of the seasonal and local time variations of the high-altitude sporadic Na layer (Nas) formation and the associated midlatitude descending E layer (Es) in lower E region

    NASA Astrophysics Data System (ADS)

    Yuan, T.; Wang, Jihong; Cai, Xuguang; Sojka, J.; Rice, D.; Oberheide, J.; Criddle, N.

    2014-07-01

    Recent studies have suggested that the major reservoir for the sporadic sodium layer (Nas) above 95 km in altitude is likely the sodium ion (Na+) within the sporadic E layer (Es) in the lower E region. However, theoretical and laboratory works have demonstrated that the metal ion's neutralization process is quite difficult above 100 km, while intensive neutral metal layers are consistently observed in the lower E region between 100 km and 125 km. In this paper, the multiyear observations of a Na lidar and an ionosonde at Utah State University (41.7°N, 111.8°W) and the nearby Bear Lake Observatory (41.9°N, 111.4°W) are utilized to understand their seasonal and local time variations. The comparison study between this set of the Nas and the nocturnal Nas observations in Beijing China (40.2°N, 116.1°E) reveals similar variations, but major differences are also noticed. To investigate the mechanism of these variations, the Hamburg Model of the Neutral and Ionized Atmosphere and the Climatological Tidal Model of the Thermosphere are utilized to simulate the ion vertical drift in the lower E region. The simulation shows that the lower E region is dominated by convergence of metal ions in summer, and ion diffusion prevails during winter. The tidal wind modulates the ion vertical drift speed and increases the likelihood of Es evolution at certain local times during the summer, while the tidal components of atmospheric density facilitate Nas formation by neutralizing the Na+ within the Es.

  16. Electric Machines with Non-Radially Mounted Rectangular Permanent Magnets / Elektrisk?s Maš?nas Ar Prizmatiskiem Neradi?li Novietotiem Past?v?gajiem Magn?tiem

    NASA Astrophysics Data System (ADS)

    Levin, N.; Pugachev, V.; Dirba, J.; Lavrinovicha, L.

    2013-04-01

    The authors analyze the advantages and disadvantages of brushless synchronous electric machines with radially and non-radially mounted rectangular permanent magnets. The results show that the proposed nonradial mounting of permanent magnets considered in the paper, in several cases (e.g. multi-pole brushless generators with tooth windings of the armature) allows achievement of the following advantages: better technology of manufacturing the electric machine owing to simple packing of the stator winding in the stator open slots, which also increases the copper slot fillfactor; reduction in the mass-and-size of permanent magnets at least twice; significantly lower cost of the electric machine; and, finally, its greater specific power. Darb? tiek analiz?tas priekšroc?bas un tr?kumi sinhron?m bezkontaktu maš?n?m ar radi?li un neradi?li novietotiem prizmatiskiem past?v?gajiem magn?tiem. Par?d?ts, ka vair?kos gad?jumos, piem?ram, daudzpolu bezkontaktu sinhronajos ?eneratoros ar zobu tinumiem, neradi?ls past?v?go magn?tu izvietojums nodrošina vair?kas priekšroc?bas: uzlabojas maš?nas izgatavošanas tehnolo?ija, jo statora atv?rtaj?s riev?s viegl?k novietot tinumus un iesp?jams sasniegt augst?ku rievas aizpild?juma koeficientu; samazin?s past?v?go magn?tu masa un izmaksas; palielin?s maš?nas ?patn?ja jauda.

  17. The Genetics Panel of the NAS BEAR I Committee (1956): epistolary evidence suggests self-interest may have prompted an exaggeration of radiation risks that led to the adoption of the LNT cancer risk assessment model.

    PubMed

    Calabrese, Edward J

    2014-09-01

    This paper extends a series of historical papers which demonstrated that the linear-no-threshold (LNT) model for cancer risk assessment was founded on ideological-based scientific deceptions by key radiation genetics leaders. Based on an assessment of recently uncovered personal correspondence, it is shown that some members of the United States (US) National Academy of Sciences (NAS) Biological Effects of Atomic Radiation I (BEAR I) Genetics Panel were motivated by self-interest to exaggerate risks to promote their science and personal/professional agenda. Such activities have profound implications for public policy and may have had a significant impact on the adoption of the LNT model for cancer risk assessment. PMID:24993953

  18. Comparison of methods for the calculation of thermal contact resistance of the first Brazilian satellite. M.S. Thesis - Instituto de Pesquisas Espaciais, 6 Dec. 1985

    NASA Technical Reports Server (NTRS)

    Mantelli, Marcia B. H.

    1988-01-01

    A comparative study of the methods developed for the calculation of thermal contact resistance between two surfaces submitted to a perpendicular heat flux is presented. Several factors affecting this resistance are analyzed and a brief historical review of the works in this field is made, spotting the methods of interest for space applications. These are compared to experimental data so as to establish the most proper method for the couplings of the first Brazilian satellite.

  19. Response to Questions on Presentation to NAS

    SciTech Connect

    Meier, W R

    2011-03-17

    Response to questions on the presentation 'Overview to Chamber and Power Plant Designs for IFE' made at the 1/29-31 meeting of the National Academies Committee on the Prospects for Inertial Confinement Fusion Energy Systems.

  20. F/NAS/ Pressure Temperature Retrieval Techniques

    NASA Technical Reports Server (NTRS)

    Poularikas, Alexander

    1995-01-01

    The purpose of this investigation is to study methods and ways for rapid inversion programs involving the correlated k-method, and to modify the existing programs so that the rapid analysis of data can be accomplished. This short paper presents the background regarding the research as well as accomplishments made during the contract period.

  1. Ecological risk assessment framework -- the NAS perspective

    SciTech Connect

    Barnthouse, L.W.

    1993-06-01

    A Workshop on Ecological Risk Assessment was held on February 26--March 1, 1991, at Airlie House, Warrenton, Virginia. In addition to presentation and discussion of the case study papers, the workshop included breakout sessions to discuss conceptual and technical aspects of ecological risk assessment. A general consensus emerged that an ecological version of the 1983 framework is desirable and feasible. The committee concluded that the 1983 human health framework could be expanded to accomodate both human health and ecological risk assessment. For general applicability to ecological assessments, the 1983 scheme requires augmentation to address some of the interfaces between science and management, primarily because of the need to focus on appropriate questions relevant to applicable environmental law and policy under different circumstances. Specifically, the scheme needs modification to address (1) the influence of legal and regulatory considerations on the initial stages of ecological risk assessment and (2) the importance of characterizing ecological risks in terms that are intelligible to risk managers. The committee`s opinion is that these augmentations are as important for human health risk assessment as they are for ecological risk assessment. This paper briefly describes the framework recommended by the Committee and compares it to EPA`s recently-published Framework for Ecological Risk Assessment.

  2. NAS Report Reveals Dangers From SST

    ERIC Educational Resources Information Center

    Fowler, Jo Ann V.

    1973-01-01

    Reported are some harmful effects of supersonic travel on humans and other living organisms. Slight decreases in ozone concentration as a result of emissions from the SST aircrafts reduce absorption of ultraviolet radiation. Effects of this may include skin cancer, distort balance of activity in cells and have a deleterious effect on insects and…

  3. NAS Report Reveals Dangers From SST

    ERIC Educational Resources Information Center

    Fowler, Jo Ann V.

    1973-01-01

    Reported are some harmful effects of supersonic travel on humans and other living organisms. Slight decreases in ozone concentration as a result of emissions from the SST aircrafts reduce absorption of ultraviolet radiation. Effects of this may include skin cancer, distort balance of activity in cells and have a deleterious effect on insects and…

  4. Multiband GaNAsP Quaternary Alloys

    SciTech Connect

    Yu, K.M.; Walukiewicz, W.; Ager III, J.W.; Bour, D.; Farshchi,R.; Dubon, O.D.; Li, S.X.; Sharp, I.D.; Haller, E.E.

    2005-12-08

    We have synthesized GaN{sub x}As{sub 1-y}P{sub y} alloys (x {approx} 0.3-1% and y = 0-0.4) using nitrogen N ion implantation into GaAsP epilayers followed by pulsed laser melting and rapid thermal annealing techniques. As predicted by the band anticrossing model, the incorporation of N splits the conduction band (E{sub M}) of the GaAs{sub 1-y}P{sub y} substrate, and strong optical transitions from the valence band to the lower (E{sub -}) and upper (E{sub +}) conduction subbands are observed. The relative strengths of the E{sub -} and E{sub +} transition change as the localized N level E{sub N} emerges from the conduction band forming narrow intermediate band for y > 0.3. The results show that GaN{sub x}As{sub 1-x-y}P{sub y} alloys with y > 0.3 is a three band semiconductor alloy with potential applications for high-efficiency intermediate band solar cells.

  5. NAS President Lauds NSF Peer Review System

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1977

    1977-01-01

    A National Academy of Sciences study of the National Science Foundation's system for evaluating research grant applications reveals it to be fair and equitable and refutes charges of bias favoring older, established scientists. (MLH)

  6. NAS Forums Focus on National Science Topics

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1973

    1973-01-01

    A series of public meetings designed to focus on complex and persistent problems of national importance involving science has been launched. Topics such as drugs, energy, and natural disasters are included. (DF)

  7. The NAS perchlorate review: Adverse effects?

    SciTech Connect

    Johnston, Richard B.; Corley, Rick A.; Cowan, Linda; Utiger, Robert D.

    2005-11-01

    To the editor: Drs. Ginsberg and Rice argue that the reference dose for perchlorate of 0.0007 mg/kg per day recommended by the National Academies’ Committee to Assess the Health Implications of Perchlorate Ingestion is not adequately protective. As members of the committee, we disagree. Ginsberg and Rice base their conclusion on three points. The first involves the designation of the point of departure as a NOEL (no-observed-effect level) versus a LOAEL (lowest-observed-adverse- effect level). The committee chose as its point of departure a dose of perchlorate (0.007 mg/kg per day) that when given for 14 days to 7 normal subjects did not cause a significant decrease in the group mean thyroid iodide uptake (Greer et al. 2002). Accordingly, the committee considered it a NOEL. Ginsberg and Rice focus on the fact that only 7 subjects were given that dose, and they 1seem to say that attention should be paid only to the results in those subjects in whom there was a 1fall in thyroid iodide uptake, and that the results in those in whom there was no fall or an increase should be ignored. They consider the dose to be a LOAEL because of the fall in uptake in those few subjects. It is important to note that a statistically significant decrease of, for example, 5% or even 10%, would not be biologically important and, more important, would not be sustained. For example, in another study (Braverman et al. 2004), administration of 0.04 mg/kg per day to normal subjects for 6 months had no effect on thyroid iodide uptake when measured at 3 and 6 months, and no effect on serum thyroid hormone or thyrotropin concentrations measured monthly (inspection of Figure 5A in the paper by Greer et al. suggests that this dose would inhibit thyroid iodide uptake by about 25% if measured at 2 weeks). The second issue involves database uncertainty. In clinical studies, perchlorate has been administered prospectively to 68 normal subjects for 2 weeks to 6 months. In one study (Brabant et al. 1992), a dose of 9.2 mg/kg per day for 4 weeks had no effect on thyroid function. In occupational studies, doses as high as 0.5 mg/kg per day were not associated with adverse effects on thyroid function in workers. In epidemiologic studies, there were no abnormalities in growth or thyroid function in children exposed life-long to 100 to 120 mg of perchlorate per liter of drinking water, or in pregnant women and newborn infants similarly exposed. Given the choice of a non-adverse effect (inhibition of iodide uptake by the thyroid) as the point of departure and the multiple studies in which doses of perchlorate much larger than 0.007 mg/kg per day had no effect on any aspect of thyroid function, the committee did not apply a database uncertainty factor. Finally, Ginsberg and Rice argue that inhibition of thyroid iodide uptake is adverse. That conclusion assumes that any acute inhibition would be sustained, so that thyroid hormone production would fall. That is not the case. There is remarkable compensation for even substantial reductions in thyroid iodide uptake – and thyroid hormone production. As noted above, subjects given 0.04 mg/kg per day for 6 months and 9.2 mg/kg per day for 4 weeks―doses that certainly would inhibit thyroid iodide uptake for a few weeks―had no fall in serum thyroid hormone or rise in serum thyrotropin concentrations (the hallmark of even minor systemic thyroid deficiency). Short-term inhibition of thyroid iodide uptake is not an adverse effect; it has no adverse consequences, because there is rapid compensation mediated by several independent processes. One is upregulation of the thyroid sodium-iodide transport system, as a result of intrathyroidal iodide deficiency. The second, should there be even a very small fall in thyroid hormone production, is an increase in thyrotropin secretion, resulting in overall stimulation of the thyroid gland.

  8. F/NAS/Pressure Temperature Retrieval Techniques

    NASA Technical Reports Server (NTRS)

    Poularikas. Alexander

    1998-01-01

    The purpose of this investigation is to study methods and ways for rapid inversion programs involving the correlated k-method, and to modify the existing programs so that the rapid analysis of data can be accomplished. Extensive modifications of the software programs were introduced. These modifications were imposed on the radiative transfer models and inversion methods and resulted in incorporating some important atmospheric processes not previously considered. The software also was improved to handle several toxic gases, gases that were observed in Saturn's atmosphere, and to retrieve pressure-temperature profiles from infrared solar absorption spectra.

  9. F/NAS/ Pressure Temperature Retrieval Techniques

    NASA Technical Reports Server (NTRS)

    Poularikas, Alexander

    1998-01-01

    The purpose of this investigation is to study methods and ways for rapid inversion programs involving the correlated k-method, and to modify the existing programs so that the rapid analysis of data can be accomplished. The earth's atmosphere as well as those around the planets consist of gases which emit radiation in the infrared spectral region, providing wealth of information about chemical and physical processes in the atmosphere. The atmospheric molecular constituents absorb and radiate by vibrational and rotational transitions, and the observed spectra exhibit characteristic spectral features in the region of the electromagnetic spectrum. The observed absorption or thermal emission spectra may be obtained with space-borne high resolution infrared spectrometers the 50-1000 micrometers spectral region. A detailed analysis of the observed spectra leads to information about the atmospheric thermal structure, composition, and the physical and chemical processes. The analytic techniques involve the development of radiative transfer models for the calculation of the observed radiance and transmittances for realistic atmospheric conditions and observational geometries, and the development of inversion methods for retrieval of atmospheric parameters from the observations.

  10. PM - EMISSION CHARACTERIZATION, FACTORS AND CONTROLS (NAS 12)

    EPA Science Inventory

    The program will focus on diesel trucks, prescribed and open burning, construction sites and residential wood combustion. Differences in emission rates due to changes in operating conditions and fuel type will be included in the revised factors. Ammonia research will produce i...

  11. UAS Integration in the NAS Project and Future Autonomy Research

    NASA Technical Reports Server (NTRS)

    Johnson, Charles W.

    2014-01-01

    This presentation highlights NASA use of unmanned aircraft systems (UAS) and related technologies for civil purposes. This briefing will give more insight into the UAS projects progress and future goals.

  12. NAS Associate Works on Environmental Implications of Nanoparticles

    EPA Science Inventory

    Dr. Manomita Patra joined the EPA's, Human Exposure and Atmospheric Sciences Division at the Las Vegas, NV location in June 2007. Her research project parallels her previous interests in the genotoxicity of mercury in plants. She is working with Dr. Kim Rogers and Tammy Jones-Lep...

  13. Method for a dummy CD mirror server based on NAS

    NASA Astrophysics Data System (ADS)

    Tang, Muna; Pei, Jing

    2002-09-01

    With the development of computer network, information sharing is becoming the necessity in human life. The rapid development of CD-ROM and CD-ROM driver techniques makes it possible to issue large database online. After comparing many designs of dummy CD mirror database, which are the embodiment of a main product in CD-ROM database now and in near future, we proposed and realized a new PC based scheme. Our system has the following merits, such as, supporting all kinds of CD format; supporting many network protocol; the independence of mirror network server and the main server; low price, super large capacity, without the need of any special hardware. Preliminarily experiments have verified the validity of the proposed scheme. Encouraged by the promising application future, we are now preparing to put it into market. This paper discusses the design and implement of the CD-ROM server detailedly.

  14. SITE TECHNOLOGY CAPSULE: NOVOCS EVALUATION AT NAS NORTH ISLAND

    EPA Science Inventory

    This is a SITE Technology Capsule. The MACTEC, Inc. (MACTEC), NoVOCs(TM) in-well volatile organic compounds (VOC) stripping technology is an in-situ groundwater remediation technology designed for the cleanup of groundwater contaminated with VOCs. The NoVOCs(TM) technology was ev...

  15. Flight Test Overview for UAS Integration in the NAS Project

    NASA Technical Reports Server (NTRS)

    Murphy, James R.; Hayes, Peggy S.; Kim, Sam K.; Bridges, Wayne; Marston, Michael

    2016-01-01

    The National Aeronautics and Space Administration is conducting a series of flight tests intended to support the reduction of barriers that prevent unmanned aircraft from flying without the required waivers from the Federal Aviation Administration. The most recent testing supported two separate test configurations. The first investigated the timing of Detect and Avoid (DAA) alerting thresholds using a radar-equipped unmanned vehicle and multiple live intruders flown at varying encounter geometries. The second configuration included a surrogate unmanned vehicle (flown from a ground control station, with a safety pilot on board) flying a mission in a virtual air traffic control airspace sector using research pilot displays and DAA advisories to maintain separation from live and virtual aircraft. The test was conducted over a seven-week span in the summer of 2015. The data from over 100 encounter sorties will be used to inform the RTCA Phase 1 Detect and Avoid and Command and Control Minimum Operating Performance Standards (MOPS) intended to be completed by the summer of 2016. Follow-on flight-testing is planned for the spring of 2016 to capture remaining encounters and support validation of the MOPS.

  16. Comparison of leading parallel NAS file systems on commodity hardware

    SciTech Connect

    Hedges, R; Fitzgerald, K; Gary, M; Stearman, D M

    2010-11-08

    High performance computing has experienced tremendous gains in system performance over the past 20 years. Unfortunately other system capabilities, such as file I/O, have not grown commensurately. In this activity, we present the results of our tests of two leading file systems (GPFS and Lustre) on the same physical hardware. This hardware is the standard commodity storage solution in use at LLNL and, while much smaller in size, is intended to enable us to learn about differences between the two systems in terms of performance, ease of use and resilience. This work represents the first hardware consistent study of the two leading file systems that the authors are aware of.

  17. Science and Decisions: Advancing Risk Assessment (NAS Final Report)

    EPA Science Inventory

    In August 2009, the Committee on Improving Risk Analysis Approaches Used by the U.S. EPA, National Research Council released a final report, requested and sponsored by the EPA, entitled Science and Decisions: Advancing Risk Assessment 2009.

  18. Feasibility study for a secondary Na/S battery

    NASA Technical Reports Server (NTRS)

    Abraham, K. M.; Schiff, R.; Brummer, S. B.

    1979-01-01

    The feasibility of a moderate temperature Na battery was studied. This battery is to operate at a temperature in the range of 100-150 C. Two kinds of cathode were investigated: (1) a soluble S cathode consisting of a solution of Na2Sn in an organic solvent and (2) an insoluble S cathode consisting of a transition metal dichalcogenide in contact with a Na(+)ion conducting electrolyte. Four amide solvents, dimethyl acetamide, diethyl acetamide, N-methyl acetamide and acetamide, were investigated as possible solvents for the soluble S cathode. Results of stability and electrochemical studies using these solvents are presented. The dialkyl substituted amides were found to be superior. Although the alcohol 1,3-cyclohexanediol was found to be stable in the presence of Na2Sn at 130 C, its Na2Sn solutions did not appear to have suitable electrochemical properties.

  19. Science Policy: Former NAS Official Reviews World Science.

    ERIC Educational Resources Information Center

    Malone, Thomas F.

    1982-01-01

    Issues discussed with Thomas F. Malone (former Foreign Secretary-National Academy of Sciences) include: scientists role in dealing with such global problems as nuclear war and needs in developing countries; scientific relations with China/Soviet Union; scientific enterprise/human rights; science/technology role in foreign policy; and political…

  20. Transforming the NAS: The Next Generation Air Traffic Control System

    NASA Technical Reports Server (NTRS)

    Erzberger, Heinz

    2004-01-01

    The next-generation air traffic control system must be designed to safely and efficiently accommodate the large growth of traffic expected in the near future. It should be sufficiently scalable to contend with the factor of 2 or more increase in demand expected by the year 2020. Analysis has shown that the current method of controlling air traffic cannot be scaled up to provide such levels of capacity. Therefore, to achieve a large increase in capacity while also giving pilots increased freedom to optimize their flight trajectories requires a fundamental change in the way air traffic is controlled. The key to achieving a factor of 2 or more increase in airspace capacity is to automate separation monitoring and control and to use an air-ground data link to send trajectories and clearances directly between ground-based and airborne systems. In addition to increasing capacity and offering greater flexibility in the selection of trajectories, this approach also has the potential to increase safety by reducing controller and pilot errors that occur in routine monitoring and voice communication tasks.

  1. Job Management Requirements for NAS Parallel Systems and Clusters

    NASA Technical Reports Server (NTRS)

    Saphir, William; Tanner, Leigh Ann; Traversat, Bernard

    1995-01-01

    A job management system is a critical component of a production supercomputing environment, permitting oversubscribed resources to be shared fairly and efficiently. Job management systems that were originally designed for traditional vector supercomputers are not appropriate for the distributed-memory parallel supercomputers that are becoming increasingly important in the high performance computing industry. Newer job management systems offer new functionality but do not solve fundamental problems. We address some of the main issues in resource allocation and job scheduling we have encountered on two parallel computers - a 160-node IBM SP2 and a cluster of 20 high performance workstations located at the Numerical Aerodynamic Simulation facility. We describe the requirements for resource allocation and job management that are necessary to provide a production supercomputing environment on these machines, prioritizing according to difficulty and importance, and advocating a return to fundamental issues.

  2. Comparison of Bilingual Children on the WISC-R and the Escala De Inteligencia Wechsler Para Ninos.

    ERIC Educational Resources Information Center

    Oplesch, Marie; Genshaft, Judy

    1981-01-01

    A comparison of bilingual Puerto Rican students' scores showed no significant differences between the Full Scale and the Verbal Scale scores on both tests, but significant differences between the Verbal and Performance Scale scores on both tests. Caution in testing bilingual children before determination of bilinguality is recommended. (Author)

  3. Development of Educational Resources to Include the Teaching of Astronomy in the First Years of the Basic Education. (Spanish Title: Desarrollo de Recursos Pedagógicos Para Incluir la Enseñanza de la Astronomía en los Primeros Años de la Educación Básica.) Desenvolvimento de Recursos Pedagógicos Para Inserir o Ensino de Astronomia nas Séries Iniciais do Ensino Fundamental

    NASA Astrophysics Data System (ADS)

    da Silva Morett, Samara; de Oliveira Souza, Marcelo

    2010-07-01

    In this report will be presented the development of educational resources for the presentation of concepts of astronomy in the early grades of elementary school. This material is composed by presentations developed with the use of new technological resources, by the development of experiments and by the presentation of curiosities related to this field. The experiments were constructed with low cost material in order to allow the students involved to rework them in other occasions. The material presented aims to emphasize the relationship between Astronomy and the daily life of students. The inclusion of Astronomy in elementary school is a way to demonstrate to students how this area is present in an active way in their daily lives. The classes involved in the project participated in a survey with the aim of providing information about the prior knowledge they had about topics in astronomy that were considered during the project. With the experiments conducted, and the aid of new technologies, the astronomical concepts were presented to students of 4th and 5th years of basic education of a municipal school of Campos dos Goytacazes (RJ). After the presentations new data collections were carried out with the aim of verifying the level of learning obtained and it was observed that the method used was an important tool to aid the process of teaching and learning. The project obtained good results. En este informe se presenta el desarrollo de recursos pedagógicos para la presentación de los conceptos de la astronomía en los primeros grados de la escuela primaria. Este material consiste en las presentaciones hechas con el uso de nuevos recursos tecnológicos, haciendo experimentos y análisis de objetos de interés relacionados con este ámbito. Los experimentos fueron construidos con material de bajo costo a fin de que los estudiantes involucrados podrían rehacer en otras ocasiones. El material presentado tiene como objetivo destacar la relación entre la astronomía y la vida cotidiana de los estudiantes. La inclusión de la astronomía en la escuela primaria es una manera de demostrar a los estudiantes cómo este campo está presente de forma activa en su vida cotidiana. Las clases que participan en el proyecto participaron en un estudio con el objetivo de proporcionar información a los conocimientos previos que tenían sobre los temas de la astronomía que se examinaron durante el proyecto. Con los experimentos realizados, y la ayuda de las nuevas tecnologías, conceptos astronómicos fueron presentados a los estudiantes de 4to y 5to año de la educación básica de una escuela municipal de Campos dos Goytacazes (RJ). Después de las presentaciones nuevos datos fueran colectados y se han llevado a cabo con el fin de verificar el nivel de aprendizaje alcanzado y se observó que el método utilizado fue una herramienta importante para ayudar al proceso de enseñanza y aprendizaje. El proyecto logró resultados satisfactorios. Neste trabalho será apresentado o desenvolvimento de recursos pedagógicos para a apresentação de conceitos de astronomia nas séries iniciais do ensino fundamental. Este material é composto por apresentações realizadas com o uso de novos recursos tecnológicos, pela fabricação de experimentos e a discussão de curiosidades relativas a esta área de conhecimento. Os experimentos foram construídos com material de baixo custo com o objetivo de permitir que os alunos envolvidos pudessem refazê-los em outras ocasiões. O material apresentado busca enfatizar a relação entre a astronomia e o cotidiano dos alunos. A inclusão da astronomia no ensino fundamental e uma forma de demonstrar aoestudante como esta área está presente de forma ativa em seu cotidiano. As turmas envolvidas no projeto participaram de uma pesquisa com o objetivo de obter dados relativos ao conhecimento prévio que possuíam sobre os tópicos de astronomia que foram considerados no decorrer do projeto. Com os experimentos desenvolvidos, o auxílio de novas tecnologias, foram apresentados conceitos astronômicos aos alunos do 4º e 5º anos do ensino fundamental de uma escola municipal de Campos dos Goytacazes (RJ). Após as apresentações novas coletas de dados foram realizadas com o intuito de verificar o nível de aprendizado alcançado e foi possível perceber que o método utilizado foi uma importante ferramenta de auxílio para o processo de ensino-aprendizagem. O projeto alcançou resultados satisfatórios.

  4. BOREAS TE-9 In Situ Diurnal Gas Exchange of NAS Boreal Forest Stands

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Margolis, Hank; Coyea, Marie; Dang, Qinglai

    2000-01-01

    The BOREAS TE-9 team collected several data sets related to chemical and photosynthetic properties of leaves in boreal forest tree species. The purpose of the BOREAS TE-09 study was threefold: 1) to provide in situ gas exchange data that will be used to validate models of photosynthetic responses to light, temperature, and carbon dioxide (CO2); 2) to compare the photosynthetic responses of different tree crown levels (upper and lower); and 3) to characterize the diurnal water potential curves for these sites to get an indication of the extent to which soil moisture supply to leaves might be limiting photosynthesis. The gas exchange data of the BOREAS NSA were collected to characterize diurnal gas exchange and water potential of two canopy levels of five boreal canopy cover types: young jack pine, old jack pine, old aspen, lowland old black spruce, and upland black spruce. These data were collected between 27-May-1994 and 17-Sep-1994. The data are provided in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  5. A Validation Study of Merging and Spacing Techniques in a NAS-Wide Simulation

    NASA Technical Reports Server (NTRS)

    Glaab, Patricia C.

    2011-01-01

    In November 2010, Intelligent Automation, Inc. (IAI) delivered an M&S software tool to that allows system level studies of the complex terminal airspace with the ACES simulation. The software was evaluated against current day arrivals in the Atlanta TRACON using Atlanta's Hartsfield-Jackson International Airport (KATL) arrival schedules. Results of this validation effort are presented describing data sets, traffic flow assumptions and techniques, and arrival rate comparisons between reported landings at Atlanta versus simulated arrivals using the same traffic sets in ACES equipped with M&S. Initial results showed the simulated system capacity to be significantly below arrival capacity seen at KATL. Data was gathered for Atlanta using commercial airport and flight tracking websites (like FlightAware.com), and analyzed to insure compatible techniques were used for result reporting and comparison. TFM operators for Atlanta were consulted for tuning final simulation parameters and for guidance in flow management techniques during high volume operations. Using these modified parameters and incorporating TFM guidance for efficiencies in flowing aircraft, arrival capacity for KATL was matched for the simulation. Following this validation effort, a sensitivity study was conducted to measure the impact of variations in system parameters on the Atlanta airport arrival capacity.

  6. Support of Activities of the NAS in Relation to the Radiation Effects Research Foundation

    SciTech Connect

    Douple, Evan B.

    2006-05-31

    The National Academies (NA) provides support for the activities related to the long-term follow up of the health of the survivors of the atomic bombings of Hiroshima and Nagasaki being conducted by the Radiation Effects Research Foundation (RERF) laboratories in Hiroshima and Nagasaki, Japan. The NA serves as scientific and administrative liaison between the U.S. Department of Energy (DOE) and RERF, and performs tasks in the areas of scientific oversight, information/public interface, fiscal oversight, and personnel management. The project includes recruitment and support of approximately 10 NA employees who work at RERF in Japan. Specific activities are performed consistent with the cooperative agreement’s Statement of Work between DOE and NA and consistent with an Annual Work Plan developed by DOE and NA.

  7. The Washington Alphabet Circa 1895-1905: NAS, USGS, SI, WAS, CC, GWMA, WMI, CIW

    NASA Astrophysics Data System (ADS)

    Yochelson, E. L.

    2002-05-01

    Pursuit of science as part of the Federal responsibility to the American public was vigorously defended by John Wesley Powell in the 1880s, but received serious financial setback during the next decade. The following decade saw the gradual laying of foundations for the present-day non-academic component of "big science" through the development of a series of Federal and private organizations, some which were ephemeral. A key person in this alphabet soup has the initials CDW (Charles Doolittle Walcott). His influence will be discussed and if time permits, BM, NACA and NRC will be used to demonstrate methodology.

  8. NATIONAL ACADEMY OF SCIENCES (NAS) REVIEW OF THE HEALTH IMPLICATIONS OF PERCHLORATE INGESTION (2005)

    EPA Science Inventory

    In the interest of resolving scientific questions, the EPA, the Department of Defense, the Department of Energy, and the National Aeronautics and Space Administration - members of a broader Interagency Working Group on Perchlorate led by the Office of Science and Technology Polic...

  9. UAS Integration in the NAS Project Overview: RTCA SC-228 Plenary DAA Working Group 5

    NASA Technical Reports Server (NTRS)

    Randall, Debra K.

    2014-01-01

    The presentation is intended to allow the public to know and understand NASA's plans for integrated test to allow them the opportunity to provide feedback and suggestions. The integrated testing will support verification and validation of the RTCA SC-228 UAS minimum operation performance standard requirements.

  10. Evaluation of the Terminal Precision Scheduling and Spacing System for Near-Term NAS Application

    NASA Technical Reports Server (NTRS)

    Thipphavong, Jane; Martin, Lynne Hazel; Swenson, Harry N.; Lin, Paul; Nguyen, Jimmy

    2012-01-01

    NASA has developed a capability for terminal area precision scheduling and spacing (TAPSS) to provide higher capacity and more efficiently manage arrivals during peak demand periods. This advanced technology is NASA's vision for the NextGen terminal metering capability. A set of human-in-the-loop experiments was conducted to evaluate the performance of the TAPSS system for near-term implementation. The experiments evaluated the TAPSS system under the current terminal routing infrastructure to validate operational feasibility. A second goal of the study was to measure the benefit of the Center and TRACON advisory tools to help prioritize the requirements for controller radar display enhancements. Simulation results indicate that using the TAPSS system provides benefits under current operations, supporting a 10% increase in airport throughput. Enhancements to Center decision support tools had limited impact on improving the efficiency of terminal operations, but did provide more fuel-efficient advisories to achieve scheduling conformance within 20 seconds. The TRACON controller decision support tools were found to provide the most benefit, by improving the precision in schedule conformance to within 20 seconds, reducing the number of arrivals having lateral path deviations by 50% and lowering subjective controller workload. Overall, the TAPSS system was found to successfully develop an achievable terminal arrival metering plan that was sustainable under heavy traffic demand levels and reduce the complexity of terminal operations when coupled with the use of the terminal controller advisory tools.

  11. 48 CFR 852.236-83 - Payments under fixed-price construction contracts (including NAS).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... of the contract or in accordance with the general law and regulations regarding the administration of... call system 5 Intercom system 5 Radio system 5 TV (entertainment) system 5 (c) In addition to this...

  12. 48 CFR 852.236-82 - Payments under fixed-price construction contracts (without NAS).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... under other provisions of the contract or in accordance with the general law and regulations regarding... Secondary switchgear 5 Fire alarm system 5 Nurse call system 5 Intercom system 5 Radio system 5...

  13. 48 CFR 852.236-82 - Payments under fixed-price construction contracts (without NAS).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... under other provisions of the contract or in accordance with the general law and regulations regarding... Secondary switchgear 5 Fire alarm system 5 Nurse call system 5 Intercom system 5 Radio system 5...

  14. The good, the bad, the ugly: the NAS report on strengthening forensic science in America.

    PubMed

    Kaye, David H

    2010-03-01

    In the long run, the NRC report can only have a salutary effect on forensic science. Although the report is not exhaustive in its review of the relevant literature and the law, and although broad constituencies may never embrace its most radical proposals, the report exposes the soft underbelly of a range of technologies, the organizational problems with the institutions that generate forensic science evidence, and the timidity of the courts in pushing for better science. Even if the full promise of the report is not realized, its publication ultimately should strengthen the good in a system of law and science that has its fair share of the good, the bad, and the ugly. PMID:20408376

  15. Materials Data on NaS2 (SG:122) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  16. Design of Unstructured Adaptive (UA) NAS Parallel Benchmark Featuring Irregular, Dynamic Memory Accesses

    NASA Technical Reports Server (NTRS)

    Feng, Hui-Yu; VanderWijngaart, Rob; Biswas, Rupak; Biegel, Bryan (Technical Monitor)

    2001-01-01

    We describe the design of a new method for the measurement of the performance of modern computer systems when solving scientific problems featuring irregular, dynamic memory accesses. The method involves the solution of a stylized heat transfer problem on an unstructured, adaptive grid. A Spectral Element Method (SEM) with an adaptive, nonconforming mesh is selected to discretize the transport equation. The relatively high order of the SEM lowers the fraction of wall clock time spent on inter-processor communication, which eases the load balancing task and allows us to concentrate on the memory accesses. The benchmark is designed to be three-dimensional. Parallelization and load balance issues of a reference implementation will be described in detail in future reports.

  17. Materials Data on NaS (SG:194) by Materials Project

    SciTech Connect

    Kristin Persson

    2014-11-02

    Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

  18. Implementation of BT, SP, LU, and FT of NAS Parallel Benchmarks in Java

    NASA Technical Reports Server (NTRS)

    Schultz, Matthew; Frumkin, Michael; Jin, Hao-Qiang; Yan, Jerry

    2000-01-01

    A number of Java features make it an attractive but a debatable choice for High Performance Computing. We have implemented benchmarks working on single structured grid BT,SP,LU and FT in Java. The performance and scalability of the Java code shows that a significant improvement in Java compiler technology and in Java thread implementation are necessary for Java to compete with Fortran in HPC applications.

  19. Analysis of Well-Clear Boundary Models for the Integration of UAS in the NAS

    NASA Technical Reports Server (NTRS)

    Upchurch, Jason M.; Munoz, Cesar A.; Narkawicz, Anthony J.; Chamberlain, James P.; Consiglio, Maria C.

    2014-01-01

    The FAA-sponsored Sense and Avoid Workshop for Unmanned Aircraft Systems (UAS) defnes the concept of sense and avoid for remote pilots as "the capability of a UAS to remain well clear from and avoid collisions with other airborne traffic." Hence, a rigorous definition of well clear is fundamental to any separation assurance concept for the integration of UAS into civil airspace. This paper presents a family of well-clear boundary models based on the TCAS II Resolution Advisory logic. Analytical techniques are used to study the properties and relationships satisfied by the models. Some of these properties are numerically quantifed using statistical methods.

  20. A Family of Well-Clear Boundary Models for the Integration of UAS in the NAS

    NASA Technical Reports Server (NTRS)

    Munoz, Cesar A.; Narkawicz, Anthony; Chamberlain, James; Consiglio, Maria; Upchurch, Jason

    2014-01-01

    The FAA-sponsored Sense and Avoid Workshop for Unmanned Aircraft Systems (UAS) defines the concept of sense and avoid for remote pilots as "the capability of a UAS to remain well clear from and avoid collisions with other airborne traffic." Hence, a rigorous definition of well clear is fundamental to any separation assurance concept for the integration of UAS into civil airspace. This paper presents a family of well-clear boundary models based on the TCAS II Resolution Advisory logic. For these models, algorithms that predict well-clear violations along aircraft current trajectories are provided. These algorithms are analogous to conflict detection algorithms but instead of predicting loss of separation, they predict whether well-clear violations will occur during a given lookahead time interval. Analytical techniques are used to study the properties and relationships satisfied by the models.

  1. NAS battery demonstration at American Electric Power:a study for the DOE energy storage program.

    SciTech Connect

    Newmiller, Jeff; Norris, Benjamin L. (Norris Energy Consulting Company, Martinez, CA); Peek, Georgianne Huff

    2006-03-01

    The first U.S. demonstration of the NGK sodium/sulfur battery technology was launched in August 2002 when a prototype system was installed at a commercial office building in Gahanna, Ohio. American Electric Power served as the host utility that provided the office space and technical support throughout the project. The system was used to both reduce demand peaks (peak-shaving operation) and to mitigate grid power disturbances (power quality operation) at the demonstration site. This report documents the results of the demonstration, provides an economic analysis of a commercial sodium/sulfur battery energy storage system at a typical site, and describes a side-by-side demonstration of the capabilities of the sodium/sulfur battery system, a lead-acid battery system, and a flywheel-based energy storage system in a power quality application.

  2. Transformations of citrate and Tween coated silver nanoparticles reacted with Na?S.

    PubMed

    Baalousha, M; Arkill, K P; Romer, I; Palmer, R E; Lead, J R

    2015-01-01

    Silver nanoparticles (Ag NPs) are susceptible to transformations in environmental and biological media such as aggregation, oxidation, dissolution, chlorination, sulfidation, formation/replacement of surface coatings following interaction with natural organic matter (NOM). This paper investigates the impact of surface coating and Suwannee River fulvic acid (SRFA) on the transformations and behavior of Ag NPs (citrate coated and Tween coated; cit-Ag NPs and Tween-Ag NPs, respectively), following reaction with different concentrations of Na2S solution (as a source of sulfide species, H2S and HS(-)). These transformations and the dominant mechanisms of transformations were investigated using UV-vis and scanning transmission electron microscopy coupled with electron energy loss spectroscopy. Here, we have shown that Ag NP surface coating impacts their dissolution following dilution in ultrahigh purity water, with higher extent of dissolution of Tween-Ag NPs compared with cit-Ag NPs. Tween-Ag NPs are susceptible to dissolution following their sulfidation at low S/Ag molar ratio. Suwannee River fulvic acid (SRFA) slows down the dissolution of Tween-Ag NPs at low sulfide concentrations and reduces the aggregation of cit-Ag NP in the presence of sodium sulfide. Sulfidation appears to occur by direct interaction of sulfide species with Ag NPs rather than by indirect reaction of sulfide with dissolved Ag species subsequent to dissolution. Furthermore, the sulfidation process results in the formation of partially sulfidized Ag NPs containing unreacted (metallic) subgrains at the edge of the NPs for Tween-Ag NPs in the presence of high sulfide concentration (2000nM Na2S), which occurred to less extent at lower Na2S concentration for Tween-Ag NPs and at all concentrations of Na2S for cit-Ag NPs. Thus, sulfidized Ag NPs may preserve some of the properties of the Ag NPs such as their potential to shed Ag(+) ions and their toxic potential of Ag NPs. PMID:25262296

  3. Polymers: Technical activities, 1991. NAS-NRC Assessment Panel, February 13-14, 1992

    SciTech Connect

    Smith, L.E.; Fanconi, B.M.

    1991-10-01

    All of the Division's programs are described in the report, organized according to these six Groups. These Groups have made a number of significant accomplishments during the last year. Some of these are summarized below: A computer simulation was performed to model resin flow in liquid molding of the front end structure of a Ford Escort; A NIST/industry consortium has evolved for the purpose of developing in-line measurement technology based on optical and fluorescence methods; A combined light scattering photometer/rheometer has been constructed to examine phase separation behavior of polymer blends and solutions under the influence of a simple shear field; A unique new tool has been developed to study the physics involved in the adhesion between a polymer and a solid surface like glass; The distribution of polarization in poly(vinylidene fluoride) poled by corona discharge rather than by contacting electrodes indicated positive charge injection near the surface; Proton spin diffusion results indicated domain sizes in poly(butylmethacrylate)/hydroxy modified polystyrene blends with minimum dimensions in the 6-10 nm range and stoichiometries of the order of 75/25; Novel, siloxane-containing difunctional and multifunctional vinyl monomers were prepared; The apparent 'shift' in polymer blend phase separation temperature, Tc, under shear flow has been interpreted with the mode-coupling theory for mean-field polymer blend systems; The radial flow behavior was successfully predicted from measurements in unidirectional flow; An exposure technique that rapidly determines whether or not a polymer is biodegradable has been developed; Instrumentation has been set up and calibrated to measure the dielectric constant of thin polymer films at high electric fields; A viscoelastic model of stresses in porcelain-metal strips has been developed.

  4. UAS Integration in the NAS Project Test Site Kick-off Meeting

    NASA Technical Reports Server (NTRS)

    Kopardekar, Parimal; Witzberger, Kevin; Hackenberg, Davis L.; Murphy, Jim

    2015-01-01

    This briefing was presented during the Test Site Kick Off Meeting to discuss the contract awards for Task 1 and Task 2. This briefing covered a high level overview for contract deliverables, Task 1 - UAS Traffic Management and Task 2, Live Virtual Constructive Distributed Environment.

  5. Materials reliability. Technical activities, 1990. (NAS-NRC Assessment Panel, January 31-February 1, 1991)

    SciTech Connect

    McHenry, H.I.

    1990-12-01

    Selected Highlights of the Materials Reliability Division are as follows: Composites NDE: A high resolution ultrasonic system has been developed for inspecting thick polymer-matrix composites; NDE Instruments: Field trials were conducted on two prototype ultrasonic NDE instruments. A formability sensor system was delivered to the Ford Motor Company for evaluation at their Dearborn stamping plant. An ultrasonic system for roll-by inspection of railroad wheels is being evaluated at the American Association of Railroads test track in Pueblo, Colorado; Elastic Waves in Composites: A powerful technique using a time-dependent Green's function method has been developed for studying propagation of elastic waves and their scattering from discontinuities in anisotropic solids; Electronic Packaging: Computer programs have been developed to convert coordinate points on solder joint surfaces obtained by x-ray laminography and optical inspection into finite element meshes for stress analysis; Thermomechanical Processing: The continuous cooling transformation (CCT) characteristics and the high-temperature, high strain-rate flow properties were measured for microalloyed SAE 1141 forging steel; Charpy Standards: Over 1000 industrial customers were supplied with Charpy V-notch reference specimens and calibration services for certification of Charpy impact test machines to ASTM Standard E23; Cryogenic Testing: A 5 MN (1 million pound-force) servohydraulic testing machine was refurbished and equipped with a cryostat and dewar capable of testing specimens 2 m long and 50 cm in diameter in liquid helium; Aluminum-Lithium Alloys: A cooperative program with NASA indicated that aluminum-lithium alloys have sufficient oxygen compatibility for use in cryogenic tankage for the Advanced Launch System; Automated Welding: An intelligent welding program was initiated for the U.S. Navy in conjunction with Babcock and Wilcox and INEL.

  6. Large UAS Operations in the NAS - The NASA 2007 Western States Fire Missions (WSFM)

    NASA Technical Reports Server (NTRS)

    Buoni, Gregory P.; Howell, Kathleen M.

    2008-01-01

    Objectives: Demonstrate capabilities of UAS to overfly and collect sensor data on wildfires throughout Western US. Demonstrate long-endurance mission capabilities (20+ hours). Image multiple fires (greater than 4 fires per mission), to showcase extendable mission configuration and ability to either linger over key fires or station over disparate regional fires. Deliver real-time imagery to (within 10-minutes of acquisition).

  7. 76 FR 1511 - Amendment of Class D Airspace; Fort Worth NAS JRB (Carswell Field), TX

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-11

    ...'' under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant... read as follows: Authority: 49 U.S.C. 106(g), 40103, 40113, 40120; E. O. 10854, 24 FR 9565, 3 CFR, 1959... navigation aids, at the request of the U.S. Navy, that are listed in the description. This action does...

  8. UAS Integration into the NAS: HSI Full Mission Simulation Preliminary Results

    NASA Technical Reports Server (NTRS)

    Shively, Jay; Fern, Lisa; Rorie, Conrad

    2014-01-01

    The goal of the Full Mission Sim was to examine the effects of different command and control interfaces on UAS pilots' ability to respond to ATC commands and traffic advisories. Results suggest that higher levels of automation (i.e., waypoint-to-waypoint control interfaces) lead to longer initial response times and longer edit times. The findings demonstrate the importance of providing pilots with interfaces that facilitate their ability to get back "in the loop."

  9. UAS Integration into the NAS: iHTL: DAA Display Evaluation Preliminary Results

    NASA Technical Reports Server (NTRS)

    Fern, Lisa; Rorie, Conrad; Shively, Jay

    2014-01-01

    The integrated human-in-the-loop (iHITL) simulation examined the effect of four different Detect-and-Avoid (DAA) display concepts on unmanned aircraft system (UAS) pilots' ability to maintain safe separation. The displays varied in the type and amount of guidance they provided to pilots. The study's background and methodology are discussed, followed by a presentation of the preliminary 'measured response' data (i.e., pilots' end-to-end response time in reacting to traffic alerts on their DAA display). Results indicate that display type had moderate to no affect on pilot measured response times.

  10. 48 CFR 852.236-82 - Payments under fixed-price construction contracts (without NAS).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... cost of each branch of the work. (5) The cost schedule shall include separate cost information for the... (entertainment) system 5 (c) In addition to this cost schedule, the contractor shall submit such unit costs as... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Payments under...

  11. Preliminary C3 Loading Analysis for Future High-Altitude Unmanned Aircraft in the NAS

    NASA Technical Reports Server (NTRS)

    Ho, Yan-Shek; Gheorghisor, Izabela; Box, Frank

    2006-01-01

    This document provides a preliminary assessment and summary of the command, control, and communications (C(sup 3)) loading requirements of a generic future high-altitude, long-endurance unmanned aircraft (UA) operating at in the National Airspace System. Two principal types of C(sup 3) traffic are considered in our analysis: communications links providing air traffic services (ATS) to the UA and its human pilot, and the command and control data links enabling the pilot to operate the UA remotely. we have quantified the loading requirements of both types of traffic for two different assumed levels of UA autonomy. Our results indicate that the potential use of UA-borne relays for the ATS links, and the degree of autonomy exercised by the UA during the departure and arrival phases of its flight, will be among the key drivers of C(sup 3) loading and bandwidth requirements.

  12. Protótipo do primeiro interferômetro brasileiro - BDA

    NASA Astrophysics Data System (ADS)

    Cecatto, J. R.; Fernandes, F. C. R.; Neri, J. A. C. F.; Bethi, N.; Felipini, N. S.; Madsen, F. R. H.; Andrade, M. C.; Soares, A. C.; Alonso, E. M. B., Sawant, H. S.

    2004-04-01

    A interferometria é uma poderosa ferramenta usada para investigar estruturas espaciais de fontes astrofísicas fornecendo uma riqueza de detalhes inatingível pelas técnicas convencionais de imageamento. Em particular, a interferometria com ondas de rádio abre o horizonte de conhecimento do Universo nesta ampla banda do espectro eletromagnético, que vai de cerca de 20 kHz até centenas de GHz já próximo ao infravermelho, e que está acessível a partir de instrumentos instalados em solo. Neste trabalho, apresentamos o interferômetro designado por Arranjo Decimétrico Brasileiro (BDA). Trata-se do primeiro interferômetro a ser desenvolvido no Brasil e América Latina que já está em operação na fase de protótipo. Apresentamos o desenvolvimento realizado até o momento, o sítio de instalação do instrumento, o protótipo e os principais resultados dos testes de sua operação, as perspectivas futuras e a ciência a ser desenvolvida com o instrumento nas fases II e III. Neste trabalho é dada ênfase ao desenvolvimento, testes de operação e principais resultados do protótipo. É discutida brevemente a ciência que pode ser feita com o instrumento. Tanto os detalhes técnicos quanto os principais parâmetros estimados para o instrumento nas próximas fases de desenvolvimento e o desempenho do protótipo serão publicados em breve.

  13. Observacoes do Cometa de Halley no Continuo de 22 GHz E 44 GHz, E NA Raia Maser de Vapor de H20 EM 22.2 GHz

    NASA Astrophysics Data System (ADS)

    Abraham, Z.; Scalise, E., Jr.; Botti, L. C. L.; Cancoro, A. C. O.; Monteiro Do Vale, J. L.; del Ciampo, L. F.; Tateyama, C. E.; Vilas Boas, J. W. S.; Homor, J. L.; Kaufmann, P.

    1987-05-01

    0 cometa de Halley foi observado no contínuo nas frequencias de 22 GHz e 44 GHz no Observatório de Itapetinga, Brasil, no período Fevereiro-Abril de 1986. 0 cometa foi detetado em ambas frequ?ncias, apresentando variabilidade corn escalas de tempo de horas. Cálculos teóricos mostram que a radicão não pode ser devida a transicões livre-livre na região ionizada resultante da interacão do cometa corn 0 vento solar. A emissão seria então devida à radiacão térmica dos gráos da coma do cometa, cuja densidade também foi variável em intervalo de horas. Não foi detetada emissão maser de H2O maior que 4 Jy.

  14. Astronomia Motivadora no Ensino Fundamental

    NASA Astrophysics Data System (ADS)

    Melo, J.; Voelzke, M. R.

    2008-09-01

    O objetivo principal deste trabalho é procurar desenvolver o interesse dos alunos pelas ciências através da Astronomia. Uma pesquisa com perguntas sobre Astronomia foi realizada junto a 161 alunos do Ensino Fundamental, com o intuito de descobrir conhecimentos prévios dos alunos sobre o assunto. Constatou-se, por exemplo, que 29,3% da 6ª série responderam corretamente o que é eclipse, 30,0% da 8ª série acertaram o que a Astronomia estuda, enquanto 42,3% dos alunos da 5ª série souberam definir o Sol. Pretende-se ampliar as turmas participantes e trabalhar, principalmente de forma prática com: dimensões e escalas no Sistema Solar, construção de luneta, questões como dia e noite, estações do ano e eclipses. Busca-se abordar, também, outros conteúdos de Física tais como a óptica na construção da luneta, e a mecânica no trabalho com escalas e medidas, e ao utilizar uma luminária para representar o Sol na questão do eclipse, e de outras disciplinas como a Matemática na transformação de unidades, regras de três; Artes na modelagem ou desenho dos planetas; a própria História com relação à busca pela origem do universo, e a Informática que possibilita a busca mais rápida por informações, além de permitir simulações e visualizações de imagens importantes. Acredita-se que a Astronomia é importante no processo ensino aprendizagem, pois permite a discussão de temas curiosos como, por exemplo, a origem do universo, viagens espaciais a existência ou não de vida em outros planetas, além de temas atuais como as novas tecnologias.

  15. Preparación de los adultos mayores en los Estados Unidos para hacer frente a los desastres naturales: encuesta a escala nacional*

    PubMed Central

    Al-rousan, Tala M.; Rubenstein, Linda M.; Wallace, Robert B.

    2015-01-01

    Objetivos. Nos propusimos determinar el grado de preparación frente a los desastres naturales de los adultos mayores en los Estados Unidos y evaluar los factores que pueden afectar negativamente la salud y la seguridad durante este tipo de incidentes. Métodos. Obtuvimos una muestra de adultos de 50 años en adelante (n = 1 304) de la encuesta del 2010 del Estudio de la Salud y la Jubilación (HRS por su sigla en inglés). La encuesta recogió datos sobre las características demográficas generales, el estado de discapacidad o las limitaciones funcionales, y también sobre factores y comportamientos relacionados con la preparación frente a los desastres. Calculamos una puntuación global de preparación mediante indicadores individuales a fin de evaluar el grado de preparación general. Resultados. La media de la edad de los participantes (n = 1 304) fue de 70 años (desviación estándar [DE] = 9,3). Solo 34,3% informaron que habían participado en un programa formativo o que habían leído materiales sobre la preparación para los desastres. Casi 15% indicaron que usaban dispositivos médicos eléctricos que podían correr riesgo de no funcionar si se interrumpiera el suministro eléctrico. La puntuación de preparación indicó que la edad más avanzada, la discapacidad física y el menor nivel de escolaridad y de ingresos se asociaban independiente y significativamente a un grado de preparación general inferior. Conclusiones. A pesar de la mayor vulnerabilidad ante los desastres y del número cada vez mayor de adultos mayores en los Estados Unidos, muchos de los problemas sustanciales que encontramos son remediables y requieren atención en los sectores de la sociedad dedicados a la atención clínica, a la salud pública y al manejo de situaciones de emergencia.

  16. La Apaicultura de Pequena Escala (Small Scale Beekeeping). Appropriate Technologies for Development. Peace Corps Information Collection & Exchange Manual Series No. M-25.

    ERIC Educational Resources Information Center

    Gentry, Curtis

    This Spanish-language manual is designed to assist Peace Corps volunteers in Spanish-speaking countries in the implementation of small-scale beekeeping programs as a tool for development. Addressed in the individual chapters are bees and humans; project planning; the types and habits of bees; the essence of beekeeping; bee space and beehives;…

  17. Band-gap energies, free carrier effects, and phonon modes in strained GaNAs/GaAs and GaNAs/InAs/GaAs superlattice heterostructures measured by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Šik, J.; Schubert, M.; Leibiger, G.; Gottschalch, V.; Wagner, G.

    2001-01-01

    Spectroscopic ellipsometry (SE) is employed to study the optical properties of compressively strained short-period GaAs/InAs/GaNxAs1-x (0%

  18. The Helios Prototype flying wing stretches almost the full length of the 300-foot-long hangar at NAS

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Helios Prototype flying wing stretches almost the full length of the 300-foot-long hangar at NASA's Dryden flight Research Center, Edwards, California. The 247-foot span solar-powered aircraft, resting on its ground maneuvering dolly, was on display for a visit of NASA Administrator Sean O'Keefe and other NASA officials on January 31, 2002. The unique solar-electric flying wing reached an altitude of 96,863 feet during an almost 17-hour flight near Hawaii on August 13, 2001, a world record for sustained horizontal flight by a non-rocket powered aircraft. Developed by AeroVironment, Inc., under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the Helios Prototype is the forerunner of a planned fleet of slow-flying, long duration, high-altitude uninhabited aerial vehicles (UAV) which can serve as 'atmospheric satellites,' performing Earth science missions or functioning as telecommunications relay platforms in the stratosphere.

  19. 75 FR 33615 - Draft EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments (EPA...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-14

    ... was announced in a May 21, 2010, Federal Register Notice (75 FR 28610). EPA also announced that it..., 2010, Federal Register Notice (75 FR 28805). Members of the public who wish to ensure that their... comment period for review of this draft assessment was announced previously in the Federal Register (75...

  20. A biometric latent curve analysis of memory decline in older men of the NAS-NRC twin registry.

    PubMed

    McArdle, John J; Plassman, Brenda L

    2009-09-01

    Previous research has shown cognitive abilities to have different biometric patterns of age-changes. We examined the variation in episodic memory (word recall task) for over 6,000 twin pairs who were initially aged 59-75, and were subsequently re-assessed up to three more times over 12 years. In cross-sectional analyses, variation in the number of words recalled independent of age was explained largely by non-shared influences (65-72%), with clear additive genetic influences (12-32%), and marginal shared family influences (1-18%). The longitudinal phenotypic analysis of the word recall task showed systematic linear declines over age, but several nonlinear models with more dramatic changes at later ages, improved the overall fit. A two-part spline model for the longitudinal twin data with an optimal turning point at age 74 led to: (a) a separation of non-shared environmental influences and transient measurement error (~50%); (b) strong additive genetic components of this latent curve (~44% at age 60) with increases (over 50%) up to age 74, but with no additional genetic variation after age 74; (c) the smaller influences of shared family environment (~15% at age 74) were constant over all ages; (d) non-shared effects play an important role over most of the life-span but diminish after age 74. PMID:19404731

  1. 75 FR 35800 - Draft EPA's Reanalysis of Key Issues Related to Dioxin Toxicity and Response to NAS Comments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-23

    ... public review and comment (75 FR 28610). Written comments on the draft report were to be submitted to EPA... by the SAB staff office in a separate May 24, 2010, Federal Register Notice (75 FR 28805). EPA... FR 28610). The public comment period and SAB external peer review are independent processes...

  2. NAS Experiences of Porting CM Fortran Codes to HPF on IBM SP2 and SGI Power Challenge

    NASA Technical Reports Server (NTRS)

    Saini, Subhash

    1995-01-01

    Current Connection Machine (CM) Fortran codes developed for the CM-2 and the CM-5 represent an important class of parallel applications. Several users have employed CM Fortran codes in production mode on the CM-2 and the CM-5 for the last five to six years, constituting a heavy investment in terms of cost and time. With Thinking Machines Corporation's decision to withdraw from the hardware business and with the decommissioning of many CM-2 and CM-5 machines, the best way to protect the substantial investment in CM Fortran codes is to port the codes to High Performance Fortran (HPF) on highly parallel systems. HPF is very similar to CM Fortran and thus represents a natural transition. Conversion issues involved in porting CM Fortran codes on the CM-5 to HPF are presented. In particular, the differences between data distribution directives and the CM Fortran Utility Routines Library, as well as the equivalent functionality in the HPF Library are discussed. Several CM Fortran codes (Cannon algorithm for matrix-matrix multiplication, Linear solver Ax=b, 1-D convolution for 2-D datasets, Laplace's Equation solver, and Direct Simulation Monte Carlo (DSMC) codes have been ported to Subset HPF on the IBM SP2 and the SGI Power Challenge. Speedup ratios versus number of processors for the Linear solver and DSMC code are presented.

  3. Optical properties of GaInNAs/GaAs quantum wells: character of optical transitions and carrier localisation effect

    NASA Astrophysics Data System (ADS)

    Kudrawiec, R.; Misiewicz, J.; Fisher, M.; Forchel, A.

    2004-01-01

    The set of Ga0.59In0.41NxAs1-x/GaAs single quantum wells (SQWs) with high nitrogen content (up to 5.2%) has been investigated in photoreflectance (PR) and photoluminescence (PL) spectroscopies at low and room temperatures. Strong manifestation of the carrier localisation effect due to the increase in nitrogen content has been observed. The carrier localization at low temperatures leads to a large Stokes shift and a decrease of the efficiency of band bending modulation. The second phenomena causes a significant decrease of PR signal at low temperatures. In addition, the temperature induced shift of the energy band gap significantly depends on nitrogen content. We have observed that the shift between 10 and 300 K is 82, 73, 67, and 62 meV for the SQW with the nitrogen content of 0, 2.0, 3.2, and 5.2%, respectively.

  4. Considerations in the Integration of Small Aircraft Transportation System Higher Volume Operations (SATSHVO) in the National Airspace System (NAS)

    NASA Technical Reports Server (NTRS)

    Lohr, Gary W.; Williams, Dan; Abbott, Terence; Baxley, Brian; Greco, Adam; Ridgway, Richard

    2005-01-01

    The Small Aircraft Transportation System Higher Volume Operations (SATS HVO) concept holds the promise for increased efficiency and throughput at many of the nations under-used airports. This concept allows for concurrent operations at uncontrolled airports that under today s procedures are restricted to one arrival or one departure operation at a time, when current-day IFR separation standards are applied. To allow for concurrent operations, SATS HVO proposes several fundamental changes to today's system. These changes include: creation of dedicated airspace, development of new procedures and communications (phraseologies), and assignment of roles and responsibilities for pilots and controllers, among others. These changes would affect operations on the airborne side (pilot) as well as the groundside (controller and air traffic flow process). The focus of this paper is to discuss some of the issues and potential problems that have been considered in the development of the SATS HVO concept, in particular from the ground side perspective. Reasonable solutions to the issues raised here have been proposed by the SATS HVO team, and are discussed in this paper.

  5. Pratt & Whitney/Boeing Engine Validation of Noise Reduction Concepts Final Report for NASA Contract NAS3-97144, Phase 2

    NASA Technical Reports Server (NTRS)

    Bock, Larry A.; Hauser, Joseph E.; Mathews, Douglas C.; Topol, David A.; Bielak, Gerald W.; Lan, Justin H.; Premo, John W.

    2014-01-01

    This report presents results of the work completed in Phase 2 of the Engine Validation of Noise Reduction Concepts (EVNRC) contract. The purpose of the program is to validate, through engine testing, advanced noise reduction concepts aimed at reducing engine noise up to 6 EPNdB and improving nacelle suppression by 50 percent relative to 1992 technology. Phase 1 of the program is completed and is summarized in NASA/CR-2014-218088.

  6. An estimate of the enroute noise of an advanced turboprop airplane NASA-TM-87302 E-3020 NAS 1.15:87302 HC A02/MF A01

    NASA Technical Reports Server (NTRS)

    Dittmar, J. H.

    1986-01-01

    The enroute noise of an Advanced Turboprop powered aircraft was estimated. The measured noise levels were roughly equivalent in annoyance to the noise 15.24 m from an automobile traveling at 80 km/h. It is felt that these levels would not illicit noise complaints from urban areas during the day but might be a slight annoyance in rural areas or in urban areas at night. Although it is not felt that the enroute noise is a major problem, it is indicated that a reduction in the enroute noise could improve the acceptability of advance turboprop airplanes.

  7. Critical RF damage conditions for the plasma-assisted molecular beam epitaxy growth of GaInNAs with dilute N 2/Ar gas mix

    NASA Astrophysics Data System (ADS)

    Reifsnider, Jason M.; Oye, Michael M.; Govindaraju, Sridhar; Holmes, Archie L.

    2005-06-01

    In this work, we investigate the operating conditions for RF plasma sources that employ nitrogen-argon gas mixtures for the molecular beam epitaxy growth of dilute nitride, narrow-bandgap semiconductors. The effects of RF power and gas flow rate variations are discussed, wherein a 'critical' RF power level is identified at 300 W. Growths performed at RF powers below this critical setting resulted in noticeably better quality material, which was determined from a comparison of pre- and post-anneal room temperature photoluminescence measurements. In addition to the RF power, the gas flow rate directly influences the growth chamber pressure, which in turn also affects the material quality. A modified pumping configuration was used to decouple the chamber pressure from the gas flow rate. In all growths, lower chamber pressures resulted in better material quality, irregardless of the power setting used. These results suggest that operating the nitrogen RF plasma source at its lowest possible power setting and lowest gas flow rate, while still maintaining a stable plasma, will result in the best quality of dilute nitride materials.

  8. Review of the NAS/NRC report: {open_quotes}Groundwater at Yucca Mountain: How high can it rise?{close_quotes}. Special report No. 1

    SciTech Connect

    Archambeau, C.B.

    1992-12-01

    There are three basic and serious problems that produce disagreement with the conclusions and recommendations of the Academy report entitled {open_quotes}Groundwater at Yucca Mountain: How high can it rise?{close_quotes}. These are: First, the report ignores a considerable body of critical data relating to the ages and nature of hydrothermal alterations at the site; second, many of the strong conclusions expressed in the report are not reasonably supported by the evidence presented and, in some cases, are inconsistent with data and results available to the committee but which are not cited or used by them; and finally, there are statements describing field relationships and data that are not consistent with the facts or are made in such a way as to be misleading.

  9. UAS-NAS Live Virtual Constructive Distributed Environment (LVC): LVC Gateway, Gateway Toolbox, Gateway Data Logger (GDL), SaaProc Software Design Description

    NASA Technical Reports Server (NTRS)

    Jovic, Srboljub

    2015-01-01

    This document provides the software design description for the two core software components, the LVC Gateway, the LVC Gateway Toolbox, and two participants, the LVC Gateway Data Logger and the SAA Processor (SaaProc).

  10. Teaching of Astronomy at Teresa Martin College. (Breton Title: Ensino de Astronomia Nas Faculdades Teresa Martin.) Enseñanza de la Astronomia en la Facultad Teresa Martin

    NASA Astrophysics Data System (ADS)

    Azevedo Sobreira, Paulo Henrique

    2005-12-01

    Courses with exclusive Astronomy contents did not exist at (FATEMA) Teresa Martin College's program until the end of 2002. In 2001, a series of educational experiments started in courses and classes of Astronomy at Mathematics and Geography departments. This actions culminated with the insertion of Teaching of Astronomy as a study theme in the course of Independent Studies for Mathematics professors in 2005. Até o final de 2002 inexistiam na grade curricular das Faculdades Integradas Teresa Martin (FATEMA) cadeiras com conteúdos exclusivos de Astronomia. A partir do ano de 2001 iniciou-se uma série de experiências educacionais através de modelos de cursos e de aulas de Astronomia nos Departamentos de Matemática e de Geografia, o que culminou com a inserção do Ensino de Astronomia como temática da disciplina de Estudos Independentes para o curso de Licenciatura em Matemática, em 2005. Hasta el final de 2002 no había en el currículo dela Facultad TeresaMartín (FATEMA) en San Pablo - SP, Brasil, disciplinas con contenidos exclusivos de Astronomía. A partir del año 2001 comenzó una secuencia de experimentos educacionales de carrera y de clases de Astronomía en los Departamentos de Matemática y Geografía, culminando en la implantación de clases de Enseñanza dela Astronomíaenla Licenciaturaen Matemática, en el año de 2003, y de la cátedra de extensión en Cosmografía parala Licenciaturaen Geografía.

  11. GaNAs/InGaAs Superlattice Solar Cells with High N Content in the Barrier Grown by All Solid-State Molecular Beam Epitaxy

    NASA Astrophysics Data System (ADS)

    Lu, Jian-Ya; Zheng, Xin-He; Wang, Nai-Ming; Chen, Xi; Li, Bao-Ji; Lu, Shu-Long; Yang, Hui

    2015-05-01

    Not Available Supported by the National Natural Science Foundation of China under Grant No 61274134, the University of Science and Technology Beijing Talents Start-up Program under Grant No 06105033, and the International Cooperation Projects of Suzhou City under Grant No SH201215.

  12. Observação do abrilhantamento de limbo solar e de estruturas filamentares em 48 ghz utilizando a técnica de regularização adaptativa

    NASA Astrophysics Data System (ADS)

    Machado, W. R. S.; Mascarenhas, N.; Costa, J. E. R.; Silva, A. V. R.

    2003-08-01

    O radiotelescópio do Itapetinga tem sido utilizado em campanhas de observações de explosões solares gerando um grande número de mapas diários em 48 GHz como sub-produto destas observações. A resolução espacial do telescópio de 14m do Itapetinga nesta freqüência é de aproximadamente dois minutos de arco. Estruturas de interesse para análise da atmosfera solar quiescente tais como os filamentos e o anel de abrilhantamento do limbo são de dimensão angular moderada da ordem ou ligeiramente menores que a resolução do telescópio. É conhecido que a convolução da função de espalhamento do telescópio, PSF (padrão de ganho do feixe) borra as estruturas de dimensão angular abaixo do HPBW (largura a meia potência do feixe) e portanto é comum a busca por técnicas de restauração que eliminem pelo menos em parte este borramento. Estudamos a restauração destas radioimagens usando a técnica de regularização adaptativa e os resultados ressaltam estas estruturas espaciais de pequeno contraste. O algoritmo da regularização adaptativa faz uso de k imagens, chamadas protótipos, obtidas através da variação de parâmetros de um filtro de regularização. Para controle da qualidade da restauração utilizamos uma imagem de alta resolução espacial obtida na linha H-a e a PSF do Itapetinga para borrá-la. Pequenos desvios, entre a PSF utilizada para o borramento e a PSF utilizada na restauração, produziram alguns desvios notáveis na imagem restaurada porém a adição de ruído nas simulações de restauração foram mais influentes no cálculo da rugosidade da imagem e portanto mais limitante para a restauração. Apresentamos como nosso primeiro resultado uma imagem em 48 GHz com a presença clara do abrilhantamento de limbo que não estava evidente na imagem original e traços de estruturas filamentares, porém ainda sem grande evidência.

  13. Reconstrução tridimensional de arcos magnéticos por tomografia

    NASA Astrophysics Data System (ADS)

    Simões, P. J. A.; Costa, J. E. R.

    2003-08-01

    Uma explosão solar é uma variação súbita do brilho que ocorre nas regiões ativas da atmosfera solar. Estas regiões são constituídas por um plasma magnetizado com intensa indução magnética e em cenários bem complexos como visto recentemente através de experimentos embarcados em satélites operando instrumentos em raios X moles e ultra-violeta distante. A energia magnética, que pode ser armazenada por um período de horas até dias em configurações magnéticas estressadas, é subitamente lançada na atmosfera solar e transferida para partículas como elétrons, prótons e núcleos pesados, que são acelerados e/ou aquecidos, produzindo radiação eletromagnética. A proposta final deste projeto é determinar as características espaciais de alta resolução da emissão e polarização girossincrotrônica de explosões solares em ambientes complexos de campos magnéticos. Os recentes resultados da emissão difusa em EUV apresentado pelos satélites TRACE e SOHO dos arcos magnéticos conectando as diferentes polaridades magnéticas sobre as regiões ativas possibilitam novas abordagens sobre o papel do campo magnético na emissão em rádio. Nesta etapa apresentamos os resultados da reconstrução da geometria tridimensional das linhas de força destes arcos utilizando técnicas tomográficas, a partir de imagens de alta resolução espacial obtidas pelo instrumento EIT (Extreme ultraviolet Imaging Telescope), além da modelagem das induções magnéticas por um campo dipolar e as densidades de partículas aceleradas. Utilizamos para a reconstrução geométrica, imagens tomadas em vários ângulos dos arcos devido à rotacão solar. Com estes resultados, daremos continuidade ao projeto, com os cálculos da transferência radiativa nos modos ordinário e extraordinário de propagação da radiação girossincrotrônica de explosões solares.

  14. Gradiente radial de [Mg/Fe] em duas galáxias elípticas

    NASA Astrophysics Data System (ADS)

    Milone, A.; Capelato, H.

    2003-08-01

    Basicamente, são propostos dois cenários de evolução quí mio-dinâmico para os sistemas esferoidais: (i) o hierárquico através da fusão e/ou acresção de sub-sistemas com ou sem surtos de formação estelar, e (ii) o colapso monolí tico dissipativo com formação estelar interrompida por um vento galáctico. Ambos, dentro de certos limites, conseguem explicar os gradientes internos de metalicidade estelar presentes nas galáxias elí pticas bem como a relação observada entre a metalicidade central e a massa (Mg20 vs. log sv0). No entanto, nenhum prevê uma variação interna para a razão de abundâncias Mg/Fe que indiretamente define a escala temporal da formação estelar. Empregamos a espectroscopia óptica de fenda longa com a finalidade de recuperar as histórias de formação estelar, de enriquecimento quí mico e da dinâmica dentro de determinadas regiões das galáxias. Os espectros de média resolução (FWHM = 7,1 Å) e escala angular de 1,092 arcsec/pixel foram coletados com o telescópio 1,60m do OPD/LNA. Comparamos nossas medidas de linhas de absorção com resultados espectrofotométricos de modelos de populações estelares simples - mais especificamente os í ndices do Sistema Lick como Mg2, Mg b, < Fe > e Hb - a fim de se investigar as variações internas de [Fe/H], [Mg/Fe] e idade. Para duas galáxias elí pticas, NGC 1052 e NGC 7796, pertencentes a ambientes de baixa densidade, encontramos uma variação radial da razão Mg/Fe decrescente do centro para fora em regiões de 0,6 e 1 raio efetivo respectivamente. Discutimos alguns cenários de enriquecimento quí mico para estas duas galáxias.

  15. Application of Three-Dimensional Models for the Teaching of Time Zones. (Breton Title: Aplicação de Modelos Tridimensionais Para o Ensino de Fusos Horários.) Aplicación de Modelos Tridimensionales Para la Enseñanza de Husos Horarios

    NASA Astrophysics Data System (ADS)

    Azevedo Sobreira, Paulo Henrique

    2012-07-01

    There are several interesting astronomical topics that must be addressed in the High School and Elementary/Middle School in the disciplines of Geography and of Sciences. Among them, the topic of time zones which is one of the most important to understand the correlation of the Earth's rotation and its implications on daily activities of citizens in local scale, regional and global scales which involve problems of time differences. For the teaching of time zones in the lessons of Geography, for example, there are bi-dimensional representations of thematic maps of world time zones, textbooks and atlas. It happens that teachers face some difficulties to permit its students to view three-dimensionally this astronomical phenomenon from the textbooks available in schools. The aim of this paper is to present two proposals with low-cost materials, which allow the preparation of three-dimensional models for the teaching of time zones. Há vários temas astronômicos interessantes que devem ser trabalhados nos Ensinos Médio e Fundamental, nas disciplinas de Geografia e de Ciências. Entre eles, o tema dos fusos horários que é um dos mais importantes para se correlacionar a rotação da Terra e suas implicações nas atividades cotidianas dos cidadãos em escala local, regional e global, que envolvem problemas de diferenças horárias. Para o ensino dos fusos horários nas aulas de Geografia, por exemplo, há representações bidimensionais de mapas temáticos de fusos horários mundiais, nos livros didáticos e nos atlas. Ocorre que os professores enfrentam algumas dificuldades para possibilitar aos seus alunos a visão tridimensional deste fenômeno astronômico, a partir dos materiais didáticos disponíveis nas escolas. O objetivo deste trabalho é apresentar duas propostas para a confecção de materiais de baixo custo, que possibilitem a elaboração de modelos tridimensionais para o ensino dos fusos horários. Hay algunos temas astronómicos interesantes que se deben trabajar en la enseñanza media y básica, en las asignaturas de Geografía y de Ciencias. Entre ellos, el de los husos horarios que es uno de los más importantes para correlacionar la rotación de la Tierra y sus implicaciones en las actividades diarias de los ciudadanos en escala local, regional y global, y en general, cuestiones que implican problemas de las diferencias horarias. Para la enseñanza de los husos horarios en las clases de Geografía, por ejemplo, hay representaciones bidimensionales de los mapas temáticos de husos horarios mundiales, en libros y atlas didácticos. Sin embargo, los profesores se enfrentan con algunas dificultades para hacer posible que sus alumnos tengan una visión tridimensional de este fenómeno astronómico, usando los materiales didácticos disponibles en las escuelas. El objetivo de este trabajo es presentar la construcción de dos propuestas de materiales de bajo costo, que hacen posible la elaboración de modelos tridimensionales para la enseñanza de los husos horarios.

  16. Variabilidade óptica de longo período e precessão de jato: o caso de BL Lacertae

    NASA Astrophysics Data System (ADS)

    Caproni, A.; Abraham, Z.

    2003-08-01

    Variabilidade é tipicamente uma característica de AGNs, sendo observada em toda a faixa eletromagnética. Em relação às escalas de tempo, variações desde horas até de algumas décadas foram encontradas por vários autores. Em alguns casos, análises temporais de curvas de luz mostram a existência de periodicidade nas variações observadas. Um exemplo de objeto que preenche as características mencionadas acima é BL Lacertae, o protótipo da classe BL Lac dos AGNs. Neste trabalho, nós interpretamos a variabilidade periódica de longo período detectada na curva de luz na banda B (~7,5 anos) como o resultado da periodicidade na amplificação da radiação oriunda do jato relativístico. Neste cenário, a amplificação periódica seria induzida pela precessão, que muda o ângulo entre o jato e a linha de visada. Com esta abordagem e vínculos adicionais fornecidos por observações em altas energias, nós podemos impor limites para os parâmetros do modelo de precessão, tais como o fator de Lorentz associado ao movimento global do jato, o ângulo de abertura do cone de precessão e o ângulo entre o eixo do cone e a linha de visada.

  17. A Pos-Graduacao Nas Ciencias Humanas e o Paradigma da Medicina: A Era da Especializacao. (Post-Graduation in the Human Sciences and the Paradigm of Medicine: The Era of Specialization.)

    ERIC Educational Resources Information Center

    Costa, Celio Juvenal

    2000-01-01

    Reflects on the current tendency in Brazilian higher education for greater and greater specialization, particularly in human sciences and in medicine. Calls for less specialization and a more historic and general preparation, especially in teacher education. (BT)

  18. Ground Software Maintenance Facility (GSMF) user's manual. Appendices NASA-CR-178806 NAS 1.26:178806 Rept-41849-G159-026-App HC A05/MF A01

    NASA Technical Reports Server (NTRS)

    Aquila, V.; Derrig, D.; Griffith, G.

    1986-01-01

    Procedures are presented that allow the user to assemble tasks, link, compile, backup the system, generate/establish/print display pages, cancel tasks in memory, and to TET an assembly task without having to enter the commands every time. A list of acronyms is provided. Software identification, payload checkout unit operating system services, data base generation, and MITRA operating procedures are also discussed.

  19. Nitrogen oxyanion-dependent dissociation of a two-component complex that regulates bacterial nitrate assimilation.

    PubMed

    Luque-Almagro, Victor M; Lyall, Verity J; Ferguson, Stuart J; Roldán, M Dolores; Richardson, David J; Gates, Andrew J

    2013-10-11

    Nitrogen is an essential nutrient for growth and is readily available to microbes in many environments in the form of ammonium and nitrate. Both ions are of environmental significance due to sustained use of inorganic fertilizers on agricultural soils. Diverse species of bacteria that have an assimilatory nitrate/nitrite reductase system (NAS) can use nitrate or nitrite as the sole nitrogen source for growth when ammonium is limited. In Paracoccus denitrificans, the pathway-specific two-component regulator for NAS expression is encoded by the nasT and nasS genes. Here, we show that the putative RNA-binding protein NasT is a positive regulator essential for expression of the nas gene cluster (i.e. nasABGHC). By contrast, a nitrogen oxyanion-binding sensor (NasS) is required for nitrate/nitrite-responsive control of nas gene expression. The NasS and NasT proteins co-purify as a stable heterotetrameric regulatory complex, NasS-NasT. This protein-protein interaction is sensitive to nitrate and nitrite, which cause dissociation of the NasS-NasT complex into monomeric NasS and an oligomeric form of NasT. NasT has been shown to bind the leader RNA for nasA. Thus, upon liberation from the complex, the positive regulator NasT is free to up-regulate nas gene expression. PMID:24005668

  20. Disruption of endocrine function in H295R cell in vitro and in zebrafish in vivo by naphthenic acids.

    PubMed

    Wang, Jie; Cao, Xiaofeng; Sun, Jinhua; Huang, Yi; Tang, Xiaoyan

    2015-12-15

    Oil sands process-affected water (OSPW) have been reported to exhibit endocrine disrupting effects on aquatic organisms. Although the responsible compounds are unknown, naphthenic acids (NAs) have been considered to be implicated. The current study was designed to investigate the endocrine disruption of OSPW extracted NAs (OS-NAs) and commercial NAs (C-NAs) using a combination of in vitro and in vivo assays. The effects of OS-NAs and C-NAs on steroidogenesis were assessed both at hormone levels and expression levels of hormone-related genes in the H295R cells. The transcriptions of biomarker genes involved in endocrine systems in zebrafish larvae were investigated to detect the effects of OS-NAs and C-NAs on endocrine function in vivo. Exposure to OS-NAs and C-NAs significantly increased production of 17β-estradiol (E2) and progesterone (P4), and decreased production of testosterone (T). Both OS-NAs and C-NAs significantly induced the expression of several genes involved in steroidogenesis. The abundances of transcripts of biomarker gene CYP19b, ERα, and VTG were significantly up-regulated in zebrafish larvae exposed to OS-NAs and C-NAs, which indicated that NAs had negative effects on estrogen-responsive gene transcription in vivo. These results indicated that NAs should be partly responsible for the endocrine disrupting effects of OSPW. PMID:26073515

  1. Cloning and characterization of the nicotianamine synthase gene in Eruca vesicaria subsp sativa.

    PubMed

    Huang, B L; Cheng, C; Zhang, G Y; Su, J J; Zhi, Y; Xu, S S; Cai, D T; Zhang, X K; Huang, B Q

    2015-01-01

    Nicotianamine (NA) is a ubiquitous metabolite in plants that bind heavy metals, is crucial for metal homeostasis, and is also an important metal chelator that facilitates long-distance metal transport and sequestration. NA synthesis is catalyzed by the enzyme nicotianamine synthase (NAS). Eruca vesicaria subsp sativa is highly tolerant to Ni, Pb, and Zn. In this study, a gene encoding EvNAS was cloned and characterized in E. vesicaria subsp sativa. The full-length EvNAS cDNA sequence contained a 111-bp 5'-untranslated region (UTR), a 155-bp 3'-UTR, and a 966-bp open reading frame encoding 322-amino acid residues. The EvNAS genomic sequence contained no introns, which is similar to previously reported NAS genes. The deduced translation of EvNAS contained a well-conserved NAS domain (1-279 amino acids) and an LIKI-CGEAEG box identical to some Brassica NAS and to the LIRL-box in most plant NAS, which is essential for DNA binding. Phylogenetic analysis indicated that EvNAS was most closely related to Brassica rapa NAS3 within the Cruciferae, followed by Thlaspi NAS1, Camelina NAS3, and Arabidopsis NAS3. A reverse transcription-polymerase chain reaction indicated that EvNAS expression was greatest in the leaves, followed by the flower buds and hypocotyls. EvNAS was moderately expressed in the roots. PMID:26782459

  2. Exposure and Human Health Reassessment of 2,3,7,8-Tetrachlorodibenzo-P-Dioxin (Tcdd) and Related Compounds National Academy Sciences (External Review Draft) (2004)

    EPA Science Inventory

    Dioxin Reassessment, NAS Review Draft

    On October 15, 2004, the EPA transmitted to the National Academy of Sciences (NAS) the nas-review/index.cfm">NAS Review Draft of EPA's Exposure and Human Hea...

  3. Challenges of Conflicting School Reforms: Effects of New American Schools in a High-Poverty District.

    ERIC Educational Resources Information Center

    Berends, Mark; Chun, JoAn; Schuyler, Gina; Stockly, Sue; Briggs, R. J.

    This study compared New American Schools (NAS) classrooms to non-NAS classrooms in the high poverty San Antonio, Texas, school district. NAS promoted whole-school reform to address lagging achievement and lackluster school reform attempts that produced little meaningful change. The study investigated whether NAS designs extended beyond changes in…

  4. N-Acetylserotonin and Aging-Associated Cognitive Impairment and Depression

    PubMed Central

    Oxenkrug, Gregory; Ratner, Rebbie

    2012-01-01

    Normal brain aging is associated with depression and cognitive decline. One of the mechanisms of aging-associated emotional and cognitive impairment might be the down-regulation of biosynthesis of N-acetylserotonin (NAS), one of the methoxyindole derivatives of tryptophan (TRP). Aging is associated with decreased NAS production, largely resulting from the down-regulation of beta 1 adrenoreceptors that activate serotonin N-acetyltransferase, the enzyme catalyzing formation of NAS from serotonin. NAS exerts antidepressant-like and cognition-enhancing effects. The NAS role in cognition supported by the discovery that scotophobin, decapeptide extracted from brain and associated with cognition improvement, inhibits NAS conversion into melatonin. Furthermore, NAS (and its derivatives) attenuated cognitive impairment induced by cholinergic neurotoxin and protected against beta-amyloid neurotoxicity. Considering that NAS (but not serotonin or melatonin) is a potent agonist to high-affinity BDNF tyrosine kinase (TrkB) receptors, antidepressant and cognition-enhancing effect of NAS might be mediated by activation of TrkB receptors. NAS and TRkB gradually decreased from 1 postnatal week becoming undetectable in the brains of old rats. Additional mechanisms might include non-receptor mediated anti-inflammatory and anti-oxidative effects of NAS. Therapeutic antidepressant and cognition-improving interventions might include administration of NAS and its analogs; inhibition of tryptophan - kynurenine metabolism to increase serotonin availability as a substrate for NAS biosynthesis; up-regulation of NAS formation from serotonin and down-regulation of NAS conversion into melatonin. PMID:23185714

  5. O Passado como Nacao: Imagens do Imperio nas Falas Reacionarias dos Anos 30 e 40 do Seculo XX: Uma Pequena Arqueologia do Debate Publico e Privado (The Past as Nation: Images of the Empire in the Reactionary Words of the 30s and 40s in the 20th Century: A Small Archaeology of the Public Debate versus the Private One).

    ERIC Educational Resources Information Center

    de Freitas, Marcos Cezar

    1998-01-01

    Suggests an archaeology of the public debate versus the private one in Brazil through analysis of the reactionary speech of a religious leader, Dom Jose Mauricio da Rocha, which produced innumerable representations of the Brazilian Empire. (PA)

  6. Reading: Students' Attitudes and Interests in Fourth, Fifth, and Sixth Grades in Official Portuguese Schools in the USA (A Leitura: Atitudes e Preferencias dos Educandos do 4th, 5th, e 6th Anos de Escolaridade nas Escolas Oficiais Portuguesas nos Estados Unidos da America).

    ERIC Educational Resources Information Center

    Castanho, Maria da Graca Borges

    A study investigated attitudes and preferences concerning reading among fourth-, fifth-, and sixth-grade students in Portuguese-language schools in the United States. Extrinsic factors influencing students (parents, teachers) were also analyzed. The research took place in 10 schools in 5 states. Data were obtained using questionnaires (students)…

  7. Occurrences and behaviors of naphthenic acids in a petroleum refinery wastewater treatment plant.

    PubMed

    Wang, Beili; Wan, Yi; Gao, Yingxin; Zheng, Guomao; Yang, Min; Wu, Song; Hu, Jianying

    2015-05-01

    Naphthenic acids (NAs) are one class of compounds in wastewaters from petroleum industries that are known to cause toxic effects, and their removal from oilfield wastewater is an important challenge for remediation of large volumes of petrochemical effluents. The present study investigated occurrences and behaviors of total NAs and aromatic NAs in a refinery wastewater treatment plant, located in north China, which combined physicochemical and biological processes. Concentrations of total NAs were semiquantified to be 113-392 ?g/L in wastewater from all the treatment units, and the percentages of aromatic NAs in total NAs was estimated to be 2.1-8.8%. The mass reduction for total NAs and aromatic NAs was 15±16% and 7.5±24% after the physicochemical treatment, respectively. Great mass reduction (total NAs: 65±11%, aromatic NAs: 86±5%) was observed in the biological treatment units, and antiestrogenic activities observed in wastewater from physicochemical treatment units disappeared in the effluent of the activated sludge system. The distributions of mass fractions of NAs demonstrated that biodegradation via activated sludge was the major mechanism for removing alicyclic NAs, aromatic NAs, and related toxicities in the plant, and the polycyclic NA congener classes were relatively recalcitrant to biodegradation, which is a complete contrast to the preferential adsorption of NAs with higher cyclicity (low Z value). Removal efficiencies of total NAs were 73±17% in summer, which were higher than those in winter (53±15%), and the seasonal variation was possibly due to the relatively high microbial biotransformation activities in the activated sludge system in summer (indexed by O3-NAs/NAs). The results of the investigations indicated that biotransformation of NA mixtures by the activated sludge system were largely affected by temperature, and employing an efficient adsorbent together with biodegradation processes would help cost-effectively remove NAs in petroleum effluents. PMID:25850668

  8. Estudio de Exámenes de Detección de Cáncer de Próstata, Pulmón, Colorrectal y Ovarios (PLCO): preguntas y respuestas

    Cancer.gov

    El estudio de exámenes de detección PLCO es un estudio a gran escala, aleatorizado, para determinar si el uso de ciertos exámenes selectivos de detección disminuirá el riesgo de morir por esos cuatro tipos de cáncer.

  9. Limitation of fluorescence spectrophotometry in the measurement of naphthenic acids in oil sands process water.

    PubMed

    Lu, Weibing; Ewanchuk, Andrea; Perez-Estrada, Leonidas; Sego, Dave; Ulrich, Ania

    2013-01-01

    Fluorescence spectrophotometry has been proposed as a quick screening technique for the measurement of naphthenic acids (NAs). To evaluate the feasibility of this application, the fluorescence emission spectra of NAs extracted from three oil sands process water sources were compared with that of commercial NAs. The NAs resulting from the bitumen extraction process cannot be differentiated because of the similarity of the fluorescence spectra. Separation of the fluorescent species in NAs using high performance liquid chromatography with fluorescence detector proved unsuccessful. The acidic fraction of NAs is fluorescent but the basic fraction of NAs is not fluorescent, implying that aromatic acids in NAs give rise to the fluorescent signals. The concentrations of NAs in oil sands process water were measured by Fourier transform infrared spectroscopy (FTIR), fluorescence spectrophotometry and ultra high performance liquid chromatography-time of flight/mass spectrometry (UPLC-TOF/MS). Commercial Merichem and Kodak NAs are the best standards to use when measuring NAs concentration with FTIR and fluorescence spectrophotometry. In addition, the NAs concentrations measured by fluorescence spectrophotometry are about 30 times higher than those measured by FTIR and UPLC-TOF/MS. The findings in this study underscore the limitation of fluorescence spectrophotometry in the measurement of NAs. PMID:23379948

  10. Estudo em microondas do aprisionamento e precipitação de elétrons em explosões solares

    NASA Astrophysics Data System (ADS)

    Rosal, A. C.; Costa, J. E. R.

    2003-08-01

    Uma explosão solar é uma variação rápida e intensa do brilho que ocorre nas chamadas regiões ativas da atmosfera, constituídas por um plasma magnetizado com intensa indução magnética. Os modelos de explosões solares atuais, discutidos na literatura, apresentam características de aprisionamento e precipitação de elétrons em ambientes magnéticos simplificados. Neste trabalho, nos propusemos a separar a emissão dos elétrons aprisionados da emissão dos elétrons em precipitação apenas a partir da emissão em microondas, melhorando portanto o controle sobre o conjunto de parâmetros inferidos. A emissão em microondas da população em precipitação é bastante fraca e portanto da nossa base de dados de 130 explosões observadas pelo Rádio Polarímetro de Nobeyama, em sete freqüências, apenas para 32 foi possível separar as duas componentes de emissão com uma boa razão sinal/ruído. A partir de estudos das escalas de tempo das emissões devidas à variação gradual da emissão no aprisionamento e da variação rápida da emissão dos elétrons em precipitação foi possível obter a separação utilizando um filtro temporal nas emissões resultantes. Em nossa análise destas explosões estudamos os espectros girossincrotrônicos da emissão gradual, a qual associamos provir do topo dos arcos magnéticos e da emissão de variação rápida associada aos elétrons em precipitação. Estes espectros foram calculados e dos quais inferimos que a indução magnética efetiva do topo e dos pés foi em média, Btopo = 236 G e Bpés = 577 G, inferidas das freqüências de pico dos espectros em ntopo = 11,8 GHz e npés = 14,6 GHz com leve anisotropia (pequeno alargamento espectral). O índice espectral da distribuição não-térmica de elétrons d, inferido do índice espectral de fótons da emissão em regime opticamente fino, foi de dtopo = 3,3 e dpés = 3,9. Estes parâmetros são típicos da maioria das análises realizadas em ambiente único de emissão e a relação dos índices espectrais, dpés > dtopo prioriza as interpretações com difusão em ângulo de passo devida a colisões Coulombianas. Nesta difusão o déficit de elétrons energéticos na precipitação seria uma conseqüência natural da dependência em e-3/2 das colisões elétron-próton (onde e é a energia dos elétrons).

  11. CNPq/INPE-LANDSAT system

    NASA Technical Reports Server (NTRS)

    Debarrosaguirre, J. L.

    1985-01-01

    The current status of the Brazilian LANDSAT facilities operated by Instituto de Pesquisas Espaciais (INPE) and the results achieved during the period from October 1, 1984 to August 31, 1985 are presented. INPE's Receiving Station at Cuiaba, MT, operates normally the two tracking and receiving systems it has installed, the old one (1973) for Band S and the new one (February 1983) for dual S- and X-band. Both MSS and TM recording capabilities are functional. Support to the NASA Backup Plan for MSS data also remains active. Routine recordings are being made for LANDSAT-5 only, for both MSS and TM. Originally, MSS was recorded over the full acquisition range. However, since December, 1984, due to further reduction of operational expenses, both instruments are being recorded over Brazilian territory only.

  12. Deforestation and Biogenic Trace Emissions from Brazilian Cerrado

    NASA Technical Reports Server (NTRS)

    Sinha, Ravi; Geol, P.

    1996-01-01

    The overall goal of NASA's SCAR (Smoke, Cloud and Radiation) Program is to obtain physical and chemical properties of the smoke produced by biomass burning and the effects of the smoke on the earth's radiation balance and climate. It is a joint project with the Brazilian government and their organizations, including INPE (Instituto Nacional Pesquisas Espaciais) who actively participate in all activities. Appropriate estimates of the biomass buming in the tropics is therefore essential to determine its effect on the atmosphere and on climate. The SCAR series of experiments is designed with that purpose. The present study of evaluating the burnt-out areas is to augment the data collected to date to help evaluate the effect of biomass burning.

  13. 41 CFR 102-3.180 - What does this subpart cover and how does it apply?

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... academy. For purposes of this subpart, NAS also includes the National Academy of Engineering, the Institute of Medicine, and the National Research Council. Except with respect to NAS committees that...

  14. 41 CFR 102-3.180 - What does this subpart cover and how does it apply?

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... academy. For purposes of this subpart, NAS also includes the National Academy of Engineering, the Institute of Medicine, and the National Research Council. Except with respect to NAS committees that...

  15. 41 CFR 102-3.180 - What does this subpart cover and how does it apply?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... academy. For purposes of this subpart, NAS also includes the National Academy of Engineering, the Institute of Medicine, and the National Research Council. Except with respect to NAS committees that...

  16. 36 CFR 1234.30 - How does an agency request authority to establish or relocate records storage facilities?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION RECORDS MANAGEMENT FACILITY STANDARDS FOR... submitted in writing to the Director, Space and Security Management Division (NAS), National Archives and... to the Director, Space and Security Management Division (NAS), National Archives and...

  17. 36 CFR 1234.30 - How does an agency request authority to establish or relocate records storage facilities?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION RECORDS MANAGEMENT FACILITY STANDARDS FOR... submitted in writing to the Director, Space and Security Management Division (NAS), National Archives and... to the Director, Space and Security Management Division (NAS), National Archives and...

  18. 36 CFR 1234.30 - How does an agency request authority to establish or relocate records storage facilities?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Public Property NATIONAL ARCHIVES AND RECORDS ADMINISTRATION RECORDS MANAGEMENT FACILITY STANDARDS FOR... submitted in writing to the Director, Space and Security Management Division (NAS), National Archives and... to the Director, Space and Security Management Division (NAS), National Archives and...

  19. Assessing the Progress of New American Schools: A Status Report.

    ERIC Educational Resources Information Center

    Berends, Mark

    This report presents a data-collection plan for addressing these questions: (1) What were the New American Schools (NAS) like before they implemented their restructuring design efforts? (2) How have these evolved over time? (3) Are the critical components of the NAS designs being implemented across a wide array of schools? (4) Do the NAS designs…

  20. Developmental toxicity and endocrine disruption of naphthenic acids on the early life stage of zebrafish (Danio rerio).

    PubMed

    Wang, Jie; Cao, Xiaofeng; Huang, Yi; Tang, Xiaoyan

    2015-12-01

    Oil sands process-affected water (OSPW) has been reported to exhibit adverse effects on the environment and wildlife. Although the compounds responsible are unknown, naphthenic acids (NAs) have been considered to be implicated. The current study was designed to investigate whether NAs might cause developmental toxicity and endocrine disruption on the early life stage of zebrafish (Danio rerio). The success of embryo hatch was inhibited by 2.5 mg l(-1) oil sands NAs (OS-NAs) exposure, and both OSPW NAs and commercial NAs (C-NAs) exposure resulted in a variety of developmental lesions in the fish larvae, such as yolk sac edema, pericardial edema and spinal malformation. The transcription of genes involved cytochrome P450 aromatase (CYP19a and CYP19b), estrogen receptors (ERα, ERβ1 and ERβ2), and vitellogenin (VTG) was analyzed to evaluate the endocrine disrupting effects of NAs. Significant up-regulated gene expressions of CYP19b, ERα and VTG were observed in both OS-NAs and C-NAs groups, which indicated the deleteriously estrogenic potential of NAs. These results confirmed that NAs derived from crude petroleum could negatively impact the development and endocrine function of zebrafish, and be primarily responsible for the toxicity of OSPW. PMID:25995127

  1. Pluralizing the Monoculture

    ERIC Educational Resources Information Center

    Balch, Stephen H.

    2007-01-01

    The National Association of Scholars (NAS) is now entering its twentieth year. The organization has grown over ten-fold since their national launch. When NAS made its debut, today's extensive infrastructure for higher education reform did not yet exist. In this article, the author discusses the contributions of NAS to the academe. The author also…

  2. Intrinsic Job Satisfaction, Overall Satisfaction, and Intention to Leave the Job among Nursing Assistants in Nursing Homes

    ERIC Educational Resources Information Center

    Decker, Frederic H.; Harris-Kojetin, Lauren D.; Bercovitz, Anita

    2009-01-01

    Purpose: We examined predictors of intrinsic job satisfaction, overall satisfaction, and intention to leave the job among nursing assistants (NAs). Design and Methods: The study focused on NAs who worked 30 or more hours per week in a nursing home. Data on 2,146 NAs meeting this criterion came from the 2004 National Nursing Assistant Survey, the…

  3. Fractionation of oil sands-process affected water using pH-dependent extractions: a study of dissociation constants for naphthenic acids species.

    PubMed

    Huang, Rongfu; Sun, Nian; Chelme-Ayala, Pamela; McPhedran, Kerry N; Changalov, Mohamed; Gamal El-Din, Mohamed

    2015-05-01

    The fractionation of oil sands process-affected water (OSPW) via pH-dependent extractions was performed to quantitatively investigate naphthenic acids (NAs, CnH2n+ZO2) and oxidized NAs (Ox-NAs) species (CnH2n+ZO3 and CnH2n+ZO4) using ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOFMS). A mathematical model was also developed to estimate the dissociation constant pKa for NAs species, considering the liquid-liquid extraction process and the aqueous layer acid-base equilibrium. This model provides estimated dissociation constants for compounds in water samples based on fractionation extraction and relative quantification. Overall, the sum of O2-, O3-, and O4-NAs species accounted for 33.6% of total extracted organic matter. Accumulative extracted masses at different pHs revealed that every oxygen atom added to NAs increases the pKa (i.e., O2-NAsNAsNAs), indicating that the additional O atoms exist as -OH in O3- and O4-NAs. Molecule electron-withdrawing groups such as double bonds and aromatic groups, as indicated by higher carbon and -Z number, may be responsible for the lower pKa of O2-, O3-, and O4-NAs. The model obtained estimated pKa values of 3.5 for O2-NAs, 4.8 for O3-NAs, and 6.8 for O4-NAs via nonlinear regression curve fittings. These pKa values are valuable physicochemical parameters for environmental engineering applications targeting OSPW NAs treatment. PMID:25782756

  4. Identification and transcriptional analysis of nitrate assimilation genes in the halophilic archaeon Haloferax mediterranei.

    PubMed

    Lledó, Belén; Marhuenda-Egea, Frutos C; Martínez-Espinosa, Rosa María; Bonete, María José

    2005-11-21

    Sequencing a 6,720-bp segment of the extreme halophilic archaeon Haloferax mediterranei genome has revealed the genomic organization of the putative structural genes for nitrate assimilation. We report a gene operon containing nasABC and nasD gene. nasA encodes an assimilatory nitrate reductase, nasB codes for a membrane protein with similarity to the NarK transporter, nasC encodes a protein with similarity to MobA; and nasD codes for an assimilatory ferredoxin-dependent nitrite reductase. Reverse transcription-PCR and primer extension experiments have demonstrated the existence of one polycistronic messenger nasABC and one monocistronic nasD initiated from a different promoter. The gene order and the grouping in two adjacent transcriptional units constitutes a novel organization of nas genes. The promoter regions harbor direct palindromes reminiscent of target sites for binding of a hypotetical regulatory protein(s). Transcription of the nasABC and nasD regions was found to be repressed by the presence of ammonium as nitrogen source. PMID:16182473

  5. Digestion of Nucleic Acids Starts in the Stomach.

    PubMed

    Liu, Yu; Zhang, Yanfang; Dong, Ping; An, Ran; Xue, Changhu; Ge, Yinlin; Wei, Liangzhou; Liang, Xingguo

    2015-01-01

    The ingestion of nucleic acids (NAs) as a nutritional supplement or in genetically modified food has attracted the attention of researchers in recent years. Discussions over the fate of NAs led us to study their digestion in the stomach. Interestingly, we found that NAs are digested efficiently by human gastric juice. By performing digests with commercial, recombinant and mutant pepsin, a protein-specific enzyme, we learned that the digestion of NAs could be attributed to pepsin rather than to the acidity of the stomach. Further study showed that pepsin cleaved NAs in a moderately site-specific manner to yield 3'-phosphorylated fragments and the active site to digest NAs is probably the same as that used to digest protein. Our results rectify the misunderstandings that the digestion of NAs in the gastric tract begins in the intestine and that pepsin can only digest protein, shedding new light on NA metabolism and pepsin enzymology. PMID:26168909

  6. Digestion of Nucleic Acids Starts in the Stomach

    PubMed Central

    Liu, Yu; Zhang, Yanfang; Dong, Ping; An, Ran; Xue, Changhu; Ge, Yinlin; Wei, Liangzhou; Liang, Xingguo

    2015-01-01

    The ingestion of nucleic acids (NAs) as a nutritional supplement or in genetically modified food has attracted the attention of researchers in recent years. Discussions over the fate of NAs led us to study their digestion in the stomach. Interestingly, we found that NAs are digested efficiently by human gastric juice. By performing digests with commercial, recombinant and mutant pepsin, a protein-specific enzyme, we learned that the digestion of NAs could be attributed to pepsin rather than to the acidity of the stomach. Further study showed that pepsin cleaved NAs in a moderately site-specific manner to yield 3′-phosphorylated fragments and the active site to digest NAs is probably the same as that used to digest protein. Our results rectify the misunderstandings that the digestion of NAs in the gastric tract begins in the intestine and that pepsin can only digest protein, shedding new light on NA metabolism and pepsin enzymology. PMID:26168909

  7. N-Acetylserotonin: Neuroprotection, Neurogenesis, and the Sleepy Brain

    PubMed Central

    Tosini, Gianluca; Ye, Keqiang; Iuvone, P. Michael

    2012-01-01

    N-Acetylserotonin (NAS) is a naturally occurring chemical intermediate in biosynthesis of melatonin. Previous studies have shown that NAS has different brain distribution patterns from those of serotonin and melatonin suggesting that NAS might have functions other than as a precursor or metabolite of melatonin. Indeed several studies have now shown that NAS may play an important role in mood regulation and may have antidepressant activity. Additional studies have shown that NAS stimulates proliferation of neuroprogenitor cells and prevents some of the negative effects of sleep deprivation. It is believed that the antidepressant and neurotrophic actions of NAS are due, at least in part, to the capability on this molecule to activate the TrkB receptor in a BDNF-independent manner. Emerging evidence also indicates that NAS and its derivatives have neuroprotective properties and protect retinal photoreceptor cells from light-induced degeneration. In this review we will discuss the literature about this exciting and underappreciated molecule. PMID:22585341

  8. Ultra Performance Liquid Chromatography Ion Mobility Time-of-Flight Mass Spectrometry Characterization of Naphthenic Acids Species from Oil Sands Process-Affected Water.

    PubMed

    Huang, Rongfu; McPhedran, Kerry N; Gamal El-Din, Mohamed

    2015-10-01

    Ultraperformance liquid chromatography ion mobility time-of-flight mass spectrometry (UPLC-IM-TOFMS), integrating traveling wave ion mobility spectrometry (TWIMS) with negative electrospray ionization (ESI) mode, was used to achieve two-dimensional (2D) separation (drift vs retention times) of naphthenic acids (NAs). Unprocessed and ozonated commercial NAs were used for method development. Only O2-NAs were found in unprocessed NAs with ozonation creating O3-NAs and O4-NAs. Unprocessed and ozonated oil sands process-affected waters (OSPW) were examined to validate the method for complex matrix NAs. Ozonation increased the x number for Ox-NAs (2 ≤ x ≤ 5) and also impacted the -Z number distribution. OSPW extracted using dichloromethane removed the potential for sample matrix impacts and was used for MS/MS NAs characterization. The Ox-NAs (2 ≤ x ≤ 6) were identified with O2-NAs separated into three clusters indicating isobaric and isomeric species. MS/MS was used to verify compounds, while also indicating the presence of CH3CH2S- NAs groups. This result may be useful for future studies of sulfur-NAs fate, toxicity, and treatment. Overall, the value-added information provided by UPLC-IM-TOFMS makes it a promising analytical technique for analysis of NAs in complex OSPW samples. Moreover, this methodology can be used for other matrices to investigate relative molecular sizes and to separate complex species (e.g., fatty acids, lipids), making it beneficial for environmental and bioanalytical applications. PMID:26322530

  9. Artificial sweeteners induce glucose intolerance by altering the gut microbiota.

    PubMed

    Suez, Jotham; Korem, Tal; Zeevi, David; Zilberman-Schapira, Gili; Thaiss, Christoph A; Maza, Ori; Israeli, David; Zmora, Niv; Gilad, Shlomit; Weinberger, Adina; Kuperman, Yael; Harmelin, Alon; Kolodkin-Gal, Ilana; Shapiro, Hagit; Halpern, Zamir; Segal, Eran; Elinav, Eran

    2014-10-01

    Non-caloric artificial sweeteners (NAS) are among the most widely used food additives worldwide, regularly consumed by lean and obese individuals alike. NAS consumption is considered safe and beneficial owing to their low caloric content, yet supporting scientific data remain sparse and controversial. Here we demonstrate that consumption of commonly used NAS formulations drives the development of glucose intolerance through induction of compositional and functional alterations to the intestinal microbiota. These NAS-mediated deleterious metabolic effects are abrogated by antibiotic treatment, and are fully transferrable to germ-free mice upon faecal transplantation of microbiota configurations from NAS-consuming mice, or of microbiota anaerobically incubated in the presence of NAS. We identify NAS-altered microbial metabolic pathways that are linked to host susceptibility to metabolic disease, and demonstrate similar NAS-induced dysbiosis and glucose intolerance in healthy human subjects. Collectively, our results link NAS consumption, dysbiosis and metabolic abnormalities, thereby calling for a reassessment of massive NAS usage. PMID:25231862

  10. Neonatal abstinence syndrome.

    PubMed

    Kocherlakota, Prabhakar

    2014-08-01

    Neonatal abstinence syndrome (NAS) is a result of the sudden discontinuation of fetal exposure to substances that were used or abused by the mother during pregnancy. Withdrawal from licit or illicit substances is becoming more common among neonates in both developed and developing countries. NAS continues to be an important clinical entity throughout much of the world. NAS leads to a constellation of signs and symptoms involving multiple systems. The pathophysiology of NAS is not completely understood. Urine or meconium confirmation may assist the diagnosis and management of NAS. The Finnegan scoring system is commonly used to assess the severity of NAS; scoring can be helpful for initiating, monitoring, and terminating treatment in neonates. Nonpharmacological care is the initial treatment option, and pharmacological treatment is required if an improvement is not observed after nonpharmacological measures or if the infant develops severe withdrawal. Morphine is the most commonly used drug in the treatment of NAS secondary to opioids. An algorithmic approach to the management of infants with NAS is suggested. Breastfeeding is not contraindicated in NAS, unless the mother is taking street drugs, is involved in polydrug abuse, or is infected with HIV. Future studies are required to assess the long-term effects of NAS on children after prenatal exposure. PMID:25070299

  11. Three Dimensional Sculpturing of Vertical Nanowire Arrays by Conventional Photolithography.

    PubMed

    Shi, Run; Huang, Chengzi; Zhang, Linfei; Amini, Abbas; Liu, Kai; Shi, Yuan; Bao, Shuhan; Wang, Ning; Cheng, Chun

    2016-01-01

    Ordered nanoarchitectures have attracted an intense research interest recently because of their promising device applications. They are always fabricated by self-assembling building blocks such as nanowires, nanodots. This kind of bottom up approaches is limited in poor control over height, lateral resolution, aspect ratio, and patterning. Here, we break these limits and realize 3D sculpturing of vertical ZnO nanowire arrays (NAs) based on the conventional photolithography approach. These are achieved by immersing nanowire NAs in thick photoresist (PR) layers, which enable the cutting and patterning of ZnO NAs as well as the tailoring of NAs. Our strategy of 3D sculpturing of NAs promisingly paves the way for designing novel NAs-based nanoarchitectures. PMID:26729069

  12. Three Dimensional Sculpturing of Vertical Nanowire Arrays by Conventional Photolithography

    PubMed Central

    Shi, Run; Huang, Chengzi; Zhang, Linfei; Amini, Abbas; Liu, Kai; Shi, Yuan; Bao, Shuhan; Wang, Ning; Cheng, Chun

    2016-01-01

    Ordered nanoarchitectures have attracted an intense research interest recently because of their promising device applications. They are always fabricated by self-assembling building blocks such as nanowires, nanodots. This kind of bottom up approaches is limited in poor control over height, lateral resolution, aspect ratio, and patterning. Here, we break these limits and realize 3D sculpturing of vertical ZnO nanowire arrays (NAs) based on the conventional photolithography approach. These are achieved by immersing nanowire NAs in thick photoresist (PR) layers, which enable the cutting and patterning of ZnO NAs as well as the tailoring of NAs. Our strategy of 3D sculpturing of NAs promisingly paves the way for designing novel NAs-based nanoarchitectures. PMID:26729069

  13. Mechanistic investigation of industrial wastewater naphthenic acids removal using granular activated carbon (GAC) biofilm based processes.

    PubMed

    Islam, Md Shahinoor; Zhang, Yanyan; McPhedran, Kerry N; Liu, Yang; Gamal El-Din, Mohamed

    2016-01-15

    Naphthenic acids (NAs) found in oil sands process-affected waters (OSPW) have known environmental toxicity and are resistant to conventional wastewater treatments. The granular activated carbon (GAC) biofilm treatment process has been shown to effectively treat OSPW NAs via combined adsorption/biodegradation processes despite the lack of research investigating their individual contributions. Presently, the NAs removals due to the individual processes of adsorption and biodegradation in OSPW bioreactors were determined using sodium azide to inhibit biodegradation. For raw OSPW, after 28 days biodegradation and adsorption contributed 14% and 63% of NA removal, respectively. For ozonated OSPW, biodegradation removed 18% of NAs while adsorption reduced NAs by 73%. Microbial community 454-pyrosequencing of bioreactor matrices indicated the importance of biodegradation given the diverse carbon degrading families including Acidobacteriaceae, Ectothiorhodospiraceae, and Comamonadaceae. Overall, results highlight the ability to determine specific processes of NAs removals in the combined treatment process in the presence of diverse bacteria metabolic groups found in GAC bioreactors. PMID:26410699

  14. Three Dimensional Sculpturing of Vertical Nanowire Arrays by Conventional Photolithography

    NASA Astrophysics Data System (ADS)

    Shi, Run; Huang, Chengzi; Zhang, Linfei; Amini, Abbas; Liu, Kai; Shi, Yuan; Bao, Shuhan; Wang, Ning; Cheng, Chun

    2016-01-01

    Ordered nanoarchitectures have attracted an intense research interest recently because of their promising device applications. They are always fabricated by self-assembling building blocks such as nanowires, nanodots. This kind of bottom up approaches is limited in poor control over height, lateral resolution, aspect ratio, and patterning. Here, we break these limits and realize 3D sculpturing of vertical ZnO nanowire arrays (NAs) based on the conventional photolithography approach. These are achieved by immersing nanowire NAs in thick photoresist (PR) layers, which enable the cutting and patterning of ZnO NAs as well as the tailoring of NAs. Our strategy of 3D sculpturing of NAs promisingly paves the way for designing novel NAs-based nanoarchitectures.

  15. Genetic control of nitrate assimilation in Klebsiella oxytoca. Final technical report

    SciTech Connect

    Stewart, Valley J.

    2001-04-01

    Some microorganisms can use nitrate as the sole source of nitrogen for biosynthesis. This project focused on the bacterium Klebsiella oxytoca, an enterobacterium found in soil and water. Mutagenesis and molecular cloning identified the nasFEDCBA operon encoding enzymes for the uptake and reduction of nitrate and nitrite to ammonium, and the adjacent nasR regulatory gene. Analysis of nasF operon expression revealed that transcription is activated by the Ntr (general nitrogen regulation ) system in response to nitrogen limitation. Transcription antitermination control in response to nitrate and nitrite is mediated by the NasR protein. Additional work established that the NasR protein is an RNA-binding protein that interacts with nasF operon leader RNA to control transcription readthrough.

  16. Fotometria diferencial de estrelas T Tauri

    NASA Astrophysics Data System (ADS)

    Pereira, P. C. R.; Santos-Júnior, J. M.; Cruz, W. S.

    2003-08-01

    Neste trabalho apresentamos os resultados preliminares de um monitoramento de estrelas jovens, que pretende ser de longa duração. As estrelas estão em sua maioria localizadas no complexo Lupus-Scorpius. Nosso objetivo principal é o estudo da variabilidade em escalas de tempo de minutos até vários dias para estrelas cujos períodos não estão determinados ou apresentam discrepâncias entre diferentes publicações. A técnica utilizada foi a fotometria diferencial, com exposições de 60s e 90s, com as câmaras CCD SBIG ST7E e ST8E acopladas aos telescópios Schmidt-Cassegrain LX200 (10 e 12 polegadas), instalados na Fundação Planetário da Cidade do Rio de Janeiro. Os primeiros resultados indicam que a técnica é bastante sólida com relação à instabilidade na transparência do céu, mesmo com o uso de telescópios de pequeno porte. Objetos de magnitude 14, no telescópio de 10 polegadas, apresentam dispersões na diferença de magnitudes das comparações, em torno de 0,008mag nas exposições de 60s. Note-se, ainda, que a dispersão pode ser melhorada utilizando-se a técnica de soma de imagens. Destacamos AK Sco, GW Lup, GQ Lup e TW Hya. AK Sco é uma binária que, apesar de ter a sua órbita e período cobertos espectroscopicamente (13,6dias), nunca teve seus eclipses estudados por meio de fotometria. GW Lup não tem período determinado na literatura. Temos acompanhado este objeto há alguns anos, e sugestões de períodos entre 5 e 6 dias têm sido encontradas. O objeto que mereceu maior atenção foi TW Hya por apresentar vários trabalhos fotométricos e espectroscópicos com resultados discrepantes quanto ao período rotacional, que varia de 1,8 a 4,4 dias (Rucinsky & Krautter 1983, A&A 121, 217; Herbst & Koret 1988, AJ 96, 1949; Mekkaden 1988, A&A 340, 135; Batalha et al. 2002, ApJ 580, 343). Dedicamos 13 noites para essa estrela, totalizando cerca de 2.000 pontos na curva de luz. Nossos dados indicam a presença de uma modulação com dois períodos possíveis: 2,2 ou 3,8 dias, além de variações irregulares superpostas. Foram observados, também, dois eventos súbitos, espaçados de uma hora, com amplitudes de 0,05mag e duração de aproximadamente 30 minutos. Admitindo-se que tal modulação seja originada por acréscimo sobre a superfície estelar, dois cenários são possíveis. No caso do menor período, apenas uma mancha quente seria visível. No outro caso, duas manchas seriam necessárias, explicando assim a presença de dois picos ao se colocar os pontos em fase.

  17. A derivatisation and liquid chromatography/electrospray ionisation multistage mass spectrometry method for the characterisation of naphthenic acids.

    PubMed

    Smith, B E; Rowland, S J

    2008-12-01

    Naphthenic acids (NAs) are partially uncharacterised complex mixtures of carboxylic acids, resulting from the microbial oxidation of petroleum hydrocarbons. They are associated with the fouling of pipelines and process equipment in oil production and with corrosion in oil refineries. As by-products of the rapidly expanding oil (tar) sands industries, NAs are also pollutants and have proved to be toxic to a range of organisms. They also have important beneficial uses as fungicides, tyre additives and, paradoxically, also in the manufacture of corrosion inhibitors. These features make the characterisation of NAs an important goal for analytical chemists. Here we describe the synthesis of amide derivatives of NAs for characterisation by liquid chromatography/electrospray ionisation multistage mass spectrometry (LC/ESI-MS(n)). The method was applied to commercially available carboxylic acids, novel synthetic NAs, commercial NAs refined from crude oils, crude oil NAs and Athabasca oil sands NAs. In addition to confirming the number of alicyclic rings and length of alkyl side chain substituents (confirming information from existing methods), the MS(n) results provided further structural information. Most important of these was the finding that bi- to polycyclic acids containing ethanoate side chains, in addition to alkyl substituents, were widespread amongst the oil and oil sands NAs. The latter NAs are known end members of the beta-oxidation of NAs with even carbon number alkanoate chains. Since such NA mixtures are toxic, they should be targets for bioremediation. Bioremediation of NAs can also be monitored better by application of the methods described herein. PMID:18988206

  18. Measurement of naphthenic acids in the receiving waters around an offshore oil platform by passive sampling.

    PubMed

    Harman, Christopher; Langford, Katherine; Sundt, Rolf C; Brooks, Steven

    2014-09-01

    Polar organic chemical integrative samplers (POCIS) were deployed in the vicinity of an offshore oil installation and analyzed for naphthenic acids (NAs). The POCIS accumulated a range of mono- to tetracyclic NAs, with different degrees of alkylation, with monocyclic acids being the most abundant. Currently, POCIS or similar polar samplers may be the only way to measure exposure to NAs from offshore discharges in situ. In addition, they may be a valuable tool for monitoring similar organic acids in general. PMID:24889815

  19. Growth and characterization of dilute nitride antimonides for long-wavelength optoelectronics

    NASA Astrophysics Data System (ADS)

    Yuen, Homan Bernard

    Increasing data transmission speed can satisfy the high internet bandwidth demand. Although high speeds are utilized in the fiber backbone, the cost of InP-based lasers is too expensive for the home user. The addition of nitrogen to InGaAs, forming GaInNAs, reduces the bandgap and lattice parameter simultaneously, enabling low-cost optoelectronic devices on GaAs operating at 1.3 and 1.55 mum. High-quality GaInNAs growth by molecular beam epitaxy has many challenges. Antimony was added as a surfactant and an incorporated species during growth, forming GaInNAsSb, and a dramatic increase in quality was obtained. GaInNAsSb quantum wells (QWs) have three possible barrier materials. GaAs and GaNAs barriers were used for GaInNAs devices, but GaNAsSb was a new option since antimony was thought to improve all dilute nitrides. Further investigation into the growth parameters, resultant material and optical properties, and band offsets revealed the difficulties of utilizing GaNAsSb for the QW barriers. GaInNAsSb QWs with the three barrier materials were analyzed to determine the advantages and shortcomings of each option. We determined GaAs barriers to be optimal but are more difficult to implement. GaNAs barriers, though not ideal, are the best compromise. Although antimony was considered a panacea for dilute nitride growth, it did not always improve material, as with GaNAsSb. Investigation of antimony's role and proper utilization was performed. GaInNAs, with lower indium content, has garnered attention for solar cell applications, but high concentrations of defects hinder efficiency. Antimony was added to low-indium GaInNAs in hopes of improving the optical quality. Surprisingly, antimony degraded the optical quality. The different behaviors of antimony with high and low indium concentrations were studied and the role of antimony as a reactive surfactant was confirmed. Although antimony is beneficial in certain situations, minimization of antimony incorporation in GaInNAsSb is a key parameter in improving optical quality. In conjunction with these findings and several other discoveries, GaInNAsSb (vertical cavity surface emitting lasers) VCSELs at 1.53 mum were grown. These are the longest wavelength, monolithic, GaAs-based VCSELs to our knowledge. In addition, world-record low-threshold and high-power GaInNAsSb edge emitting lasers operating at 1.55 mum were developed.

  20. Pharmacokinetics, biodistribution and metabolism of squalenoyl adenosine nanoparticles in mice using dual radio-labeling and radio-HPLC analysis

    PubMed Central

    Gaudin, Alice; Lepetre-Mouelhi, Sinda; Mougin, Julie; Parrod, Martine; Pieters, Grégory; Garcia-Argote, Sébastien; Loreau, Olivier; Goncalves, Jordan; Chacun, Hélène; Courbebaisse, Yann; Clayette, Pascal; Desmaële, Didier; Rousseau, Bernard; Andrieux, Karine; Couvreur, Patrick

    2015-01-01

    Adenosine is a pleiotropic endogenous nucleoside with potential neuroprotective pharmacological activity. However, clinical use of adenosine is hampered by its extremely fast metabolization. To overcome this limitation, we recently developed a new squalenoyl nanomedicine of adenosine [Squalenoyl-Adenosine (SQAd)] by covalent linkage of this nucleoside to the squalene, a natural lipid. The resulting nanoassemblies (NAs) displayed a dramatic pharmacological activity both in cerebral ischemia and spinal cord injury pre-clinical models. The aim of the present study was to investigate the plasma profile and tissue distribution of SQAd NAs using both Squalenoyl-[3H]-Adenosine NAs and [14C]-Squalenoyl-Adenosine NAs as respective tracers of adenosine and squalene moieties of the SQAd bioconjugate. This study was completed by radio-HPLC analysis allowing to determine the metabolization profile of SQAd. We report here that SQAd NAs allowed a sustained circulation of adenosine under its prodrug form (SQAd) for at least 1 h after intravenous administration, when free adenosine was metabolized within seconds after injection. Moreover, the squalenoylation of adenosine and its formulation as NAs also significantly modified biodistribution, as SQAd NAs were mainly captured by the liver and spleen, allowing a significant release of adenosine in the liver parenchyma. Altogether, these results suggest that SQAd NAs provided a reservoir of adenosine into the bloodstream which may explain the previously observed neuroprotective efficacy of SQAd NAs against cerebral ischemia and spinal cord injury. PMID:26087468

  1. Nursing Activities Score: an updated guideline for its application in the Intensive Care Unit.

    PubMed

    Padilha, Katia Grillo; Stafseth, Siv; Solms, Diana; Hoogendoom, Marga; Monge, Francisco Javier Carmona; Gomaa, Om Hashem; Giakoumidakis, Konstantinus; Giannakopoulou, Margarita; Gallani, Maria Cecília; Cudak, Edyta; Nogueira, Lilia de Souza; Santoro, Cristiane; Sousa, Regina Cardoso de; Barbosa, Ricardo Luis; Miranda, Dinis Dos Reis

    2015-02-01

    Objective To describe nursing workload in Intensive Care Units (ICU) in different countries according to the scores obtained with Nursing Activities Score (NAS) and to verify the agreement among countries on the NAS guideline interpretation. Method This cross-sectional study considered 1-day measure of NAS (November 2012) obtained from 758 patients in 19 ICUs of seven countries (Norway, the Netherlands, Spain, Poland, Egypt, Greece and Brazil). The Delphi technique was used in expertise meetings and consensus. Results The NAS score was 72.8% in average, ranging from 44.5% (Spain) to 101.8% (Norway). The mean NAS score from Poland, Greece and Egypt was 83.0%, 64.6% and 57.1%, respectively. The NAS score was similar in Brazil (54.0%) and in the Netherlands (51.0%). There were doubts in the understanding of five out 23 items of the NAS (21.7%) which were discussed until researchers' consensus. Conclusion NAS score were different in the seven countries. Future studies must verify if the fine standardization of the guideline can have a impact on differences in the NAS results. PMID:26761703

  2. 41 CFR Appendix A to Subpart E of... - 3-Key Points and Principles

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    .... NAS and NAPA are completely separate organizations. Each is independently chartered by the Congress for different purposes, and Congress has recognized that the two organizations are structured...

  3. 41 CFR Appendix A to Subpart E of... - 3-Key Points and Principles

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... NAS and NAPA are completely separate organizations. Each is independently chartered by the Congress for different purposes, and Congress has recognized that the two organizations are structured...

  4. 41 CFR Appendix A to Subpart E of... - 3-Key Points and Principles

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    .... NAS and NAPA are completely separate organizations. Each is independently chartered by the Congress for different purposes, and Congress has recognized that the two organizations are structured...

  5. 41 CFR Appendix A to Subpart E of... - 3-Key Points and Principles

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... NAS and NAPA are completely separate organizations. Each is independently chartered by the Congress for different purposes, and Congress has recognized that the two organizations are structured...

  6. 41 CFR Appendix A to Subpart E of... - 3-Key Points and Principles

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    .... NAS and NAPA are completely separate organizations. Each is independently chartered by the Congress for different purposes, and Congress has recognized that the two organizations are structured...

  7. Estimating naphthenic acids concentrations in laboratory-exposed fish and in fish from the wild.

    PubMed

    Young, Rozlyn F; Wismer, Wendy V; Fedorak, Phillip M

    2008-09-01

    Naphthenic acids (NAs) are the most water-soluble organic components found in the Athabasca oil sands in Alberta, Canada, and these acids are released into aqueous tailing waters as a result of bitumen extraction. Although the toxicity of NAs to fish is well known, there has been no method available to estimate NAs concentrations in fish. This paper describes a newly developed analytical method using single ion monitoring gas chromatography-mass spectrometry (GC-MS) to measure NAs in fish, down to concentrations of approximately 0.1mgkg(-1) of fish flesh. This method was used to measure the uptake and depuration of commercial NAs in laboratory experiments. Exposure of rainbow trout (Oncorhynchus mykiss) to 3mg NAsl(-1) for 9d gave a bioconcentration factor of approximately 2 at pH 8.2. Within 1d after the fish were transferred to NAs-free water, about 95% of the NAs were depurated. In addition, the analytical method was used to determine if NAs were present in four species of wild fish - northern pike (Esox lucius), lake whitefish (Coregonus clupeaformis), white sucker (Catostomus commersoni), walleye (Sander vitreus) - collected from near the oil sands. Flesh samples from 23 wild fish were analyzed, and 18 of these had no detectable NAs. Four fish (one of each species) contained NAs at concentrations from 0.2 to 2.8mgkg(-1). The GC-MS results from one wild fish presented a unique problem. However, with additional work it was concluded that the NAs concentration in this fish was <0.1mgkg(-1). PMID:18667226

  8. The Factor Structure of Preschool Learning Behaviors Scale Scores in Peruvian Children

    ERIC Educational Resources Information Center

    Hahn, Kathryn R.; Schaefer, Barbara A.; Merino, Cesar; Worrell, Frank C.

    2009-01-01

    The factor structure of the Escala de Conductas de Aprendizaje Preescolar (ECAP), a Spanish translation of the Preschool Learning Behaviors Scale (PLBS), was examined in this study. Children aged 2 to 6 years (N = 328) enrolled in public and private preschools in the Republic of Peru were rated by classroom teachers on the frequency of observable,…

  9. Optimal Short Forms of the Spanish WAIS (EIWA).

    ERIC Educational Resources Information Center

    Demsky, Yvonne; Gass, Carlton; Edwards, William T.; Golden, Charles J.

    1998-01-01

    Investigated optimal two-, three-, four-, and five-test short forms of the Escala de Inteligencia Wechsler para Adultos (EIWA), the Spanish form of the Wechsler Adult Intelligence Scale (D. Wechsler, 1956). Results with 616 adults suggest that use of the EIWA should be limited to research and tracking cognitive changes over time. (SLD)

  10. A Study of the Spanish Translation of the Wechsler Intelligence Scale for Children-Revised with Puerto Rican Children and Adolescents.

    ERIC Educational Resources Information Center

    Rodriguez, Maria D.; And Others

    Two studies were performed with Puerto Rican children and adolescents in Puerto Rico and Connecticut to determine the reliability and predictive validity of the Spanish translation of the Wechsler Intelligence Scale for Children-Revised, the Escala de Inteligencia Wechsler para Ninos-Revisada (EIWN-R). Results suggest that the EIWN-R is a reliable…

  11. The Factor Structure of Preschool Learning Behaviors Scale Scores in Peruvian Children

    ERIC Educational Resources Information Center

    Hahn, Kathryn R.; Schaefer, Barbara A.; Merino, Cesar; Worrell, Frank C.

    2009-01-01

    The factor structure of the Escala de Conductas de Aprendizaje Preescolar (ECAP), a Spanish translation of the Preschool Learning Behaviors Scale (PLBS), was examined in this study. Children aged 2 to 6 years (N = 328) enrolled in public and private preschools in the Republic of Peru were rated by classroom teachers on the frequency of observable,…

  12. Nanotecnología - Duration: 30 seconds.

    NASA Video Gallery

    Piensa en pequeño. No, más pequeño -- piensa en nano. Achícate a la "nano escala", podrías ver los átomos que forman todo Y poder moverlos. Los científicos especialistas en nanotecnología crean nue...

  13. Instantánea de nanotecnología

    Cancer.gov

    Resumen básico de la nanotecnología, la cual consiste en el diseño y la creación de dispositivos tan pequeños que solo pueden medirse a escala molecular. También se incluye información sobre las investigaciones que realiza el NCI en este campo.

  14. Investigating sprite energetics over Brazil in association with small/frontal storms

    NASA Astrophysics Data System (ADS)

    Taylor, M. J.; Pautet, P. D.; Bailey, M.; Saosabbas, F.; Pinto, O.; Holzworth, R.; Sato, M.

    2003-12-01

    As part of the sprites 2002 balloon campaign, a suite of intensified CCD cameras were used to obtain novel data on the occurrence and properties of sprites over south eastern Brazil. Measurements were made from a field station at Cachoeira Paulista (23S, 45W), and from an Embraer aircraft both operated by the INPE (Instituto Nacional de Pesquisas Espaciais). A total of eighteen transient optical events were recorded, sixteen of which exhibited vertical structures typically associated with sprites, while the other two were disc-like events, characteristic of sprite halos or elves. Coordinated measurements by the ELAT Brazilian lightning network show that all but three of these transient events were associated with positive lightning discharges generated by relatively small thunderstorms, that were induced primarily in association with the passage of strong cold fronts. Furthermore, simultaneous ELF data obtained from Syowa Station, Antarctica and Onagawa, Japan, indicate that the charge moments associated with these events ranged from 240 to 1500 C.km with a predominance of 400-600 C.km. These observations provide the first quantitative measurements of sprites over Brazil. Although our data acquisition was limited by prevailing weather conditions, the results indicate that sprites occur relatively frequently over south eastern Brazil during the fall and spring time periods, mostly in association with rapidly developing small storms or with frontal systems.

  15. Variação temporal do gradiente radial de o/h a partir de uma amostra de nebulosas planetárias

    NASA Astrophysics Data System (ADS)

    Maciel, W. J.; Costa, R. D. D.; Uchida, M. M. M.

    2003-08-01

    Gradientes radiais de abundância são observados no disco de nossa Galáxia e também em outras galáxias espirais. No caso da Galáxia, o principal problema relativo aos gradientes é sua variação temporal, que constitui um dos principais vínculos aos modelos de evolução química da Galáxia. As nebulosas planetárias são particularmente interessantes no estudo dos gradientes e suas variações, tanto espaciais como temporais. São objetos brilhantes, podendo ser observadas a grandes distâncias, e têm abundâncias relativamente precisas de diversos elementos químicos. Além disso, sendo originadas de estrelas com massas entre 0.8 e 8 massas solares na sequência principal, incluem objetos com idades e populações diferentes, o que as torna especialmente interessantes ao estudo da variação temporal dos gradientes. Neste trabalho, apresentamos resultados recentes sobre a variação temporal do gradiente de O/H a partir de uma amostra contendo cerca de 200 nebulosas, para as quais obtivemos distâncias por métodos estatísticos. As abundâncias foram parcialmente obtidas a partir de observações em Itajubá e La Silla, sendo as restantes obtidas da literatura. Os resultados mostram, pela primeira vez, evidências de um achatamento do gradiente de O/H, de -0.11 dex/kpc para -0.06 dex/kpc nos últimos 9 giga-anos ou de -0.08 dex/kpc para -0.06 dex/kpc nos últimos 5 giga-anos. Esses valores apresentam um bom acordo com alguns modelos recentes para a evolução química da Galáxia. (FAPESP/CNPq)

  16. Land-use in Amazonia and the Cerrado of Brazil: State of Knowledge and GIS Database

    NASA Technical Reports Server (NTRS)

    Nepstad, Daniel C.

    1997-01-01

    We have assembled datasets to strengthen the LargeScale Biosphere Atmosphere Experiment in Amazonia (LBA). These datasets can now be accessed through the Woods Hole Research Center homepage (www.whrc.org), and will soon be linked to the Pre-LBA homepages of the Brazilian Space Research Institute's Center for Weather and Climate Prediction (Instituto de Pesquisas Espaciais, Centro de Previsao de Tempo e Estudos Climaticos, INPE/CPTEC) and through the Oak Ridge National Laboratory, Distributed Active Archive Center (ORNL/DMC). Some of the datasets that we are making available involved new field research and/or the digitization of data available in Brazilian government agencies. For example, during the grant period we conducted interviews at 1,100 sawmills across Amazonia to determine their production of sawn timber, and their harvest intensities. These data provide the basis for the first quantitative assessment of the area of forest affected each year by selective logging (Nepstad et al, submitted to Nature). We digitized the locations of all of the rural households in the State of Para that have been mapped by the Brazilian malaria combat agency (SUCAM). We also mapped and digitized areas of deforestation in the state of Tocantins, which is comprised largely of savanna (cerrado), an ecosystem that has been routinely excluded from deforestation mapping exercises.

  17. Intermitência alfvênica gerada por caos na atmosfera solar e no vento solar

    NASA Astrophysics Data System (ADS)

    Rempel, E. L.; Chian, A. C.-L.; Macau, E. E. N.; Rosa, R. R.

    2003-08-01

    Dados medidos no vento solar rápido proveniente dos buracos coronais revelam que os plasmas no meio interplanetário são dominados por flutuações Alfvênicas, caracterizadas por uma alta correlação entre as variações do campo magnético e da velocidade do plasma. As flutuações exibem muitas características esperadas em turbulência magneto-hidrodinâmica totalmente desenvolvida, tais como intermitência e espectros contínuos. Contudo, os mecanismos responsáveis pela evolução de turbulência Alfvênica intermitente não são completamente compreendidos. Neste trabalho a teoria de caos é usada para explicar como sistemas Alfvênicos, modelados pela equação Schrödinger não-linear derivativa e pela equação Kuramoto-Sivashinsky, podem se tornar fortemente caóticos à medida em que parâmetros do plasma são variados. Pequenas perturbações no parâmetro de dissipação podem fazer com que o sistema mude bruscamente de um regime periódico, ou fracamente caótico, para um regime fortemente caótico. As séries temporais das flutuações do campo magnético nos regimes fortemente caóticos exibem comportamento intermitente, em que fases laminares ou fracamente caóticas são interrompidas por fortes estouros caóticos. É mostrado que o regime fortemente caótico é atingido quando as soluções periódicas ou fracamente caóticas globalmente estáveis interagem com soluções do sistema que são fortemente caóticas, mas globalmente instáveis. Estas soluções globalmente instáveis são conjuntos caóticos não-atrativos conhecidos como selas caóticas, e são responsáveis pelos fortes estouros nos regimes intermitentes. Selas caóticas têm sido detectadas experimentalmente em uma grande variedade de sistemas, sendo provável que elas desempenhem um papel importante na turbulência intermitente observada em plasmas espaciais.

  18. Climatic shift in patterns of shallow clouds over the Amazon

    NASA Astrophysics Data System (ADS)

    Chagnon, F. J. F.; Bras, R. L.; Wang, J.

    2004-12-01

    The Amazon rain forest has experienced dramatic changes in the past 50 years due to active deforestation. As of 2001, 15% of the 4,000,000 km2 Brazilian Amazon has been deforested [Instituto Nacional de Pesquisas Espaciais (INPE), 2003]; each year, agricultural exploitation claims an estimated 13,000 km2 of tropical forest [Achard et al., 2002]. In this paper we investigate the climatic effects caused by the observed change of the physical characteristics of the land surface (i.e., increased surface albedo, decreased root-zone depth, decreased surface roughness and decreased leaf-area index). More precisely, we examine the spatial correspondence of shallow cumulus clouds with deforestation. Through the creation of an 8-year record of thrice daily shallow cumulus cloud cover at 1 km resolution from multi-spectral satellite imagery, we quantitatively show the existence of a significant climatic shift in shallow cloudiness patterns associated with deforestation. This shift manifests itself as an enhancement of shallow cumuli over deforested patches, and has potentially important climatic, hydrologic and ecological implications.

  19. Ozone budget over the Amazon: Regional effects from biomass-burning emissions

    NASA Astrophysics Data System (ADS)

    Richardson, Jennifer L.; Fishman, Jack; Gregory, Gerald L.

    1991-07-01

    A one-dimensional, time-dependent, photochemical model is used in conjunction with data obtained during the dry-season portion of NASA's Global Tropospheric Experiment and Brazil's Instituto Nacional de Pesquisas Espaciais (INPE) (National Institute for Space Research) Amazon Boundary Layer Experiment (ABLE 2A) to simulate the chemistry of the dry-season Amazon troposphere. The background atmosphere, unperturbed by the presence of emissions from biomass burning, is simulated with inputs of surface sources and deposition of various species measured during ABLE 2A. The presence of haze layers over a region is simulated by the imposition of profiles of species characteristic of haze within the model for 12 hours. The inclusion of hydrocarbons within the modeled haze is found to approximately double the calculated in situ ozone production rate. The difference between the calculated total column ozone production rates in the haze simulation and the background simulation is the model-predicted enhancement of the in situ ozone production due to regionally transported haze layers (up to 1000 km transport distance). The predicted enhancement of ozone is between 0.3 and 2.9 × 1011molecules O3 cm-2 s-1, near the range of observed rates of ozone increase over the Amazon Basin during the dry season. This suggests that the regional transport of haze during the southern tropical burning season is an important factor in explaining the increase of ozone observed annually during this period.

  20. Otimização de procedimento de manobra para indução de reentrada de um satélite retornável

    NASA Astrophysics Data System (ADS)

    Schulz, W.; Suarez, M.

    2003-08-01

    Veículos espaciais que retornam à Terra passam por regimes de velocidade e condições de vôo distintos. Estas diferenças dificultam sua concepção aerodinâmica e o planejamento de seu retorno. A partir de uma proposta de um veículo orbital retornável (satélite SARA, em desenvolvimento no IAE/CTA) para realização de experimentos científicos e tecnológicos em ambiente de baixa gravidade, surge a necessidade de realizarem-se estudos considerando-se os aspectos relativos à sua aerodinâmica. Após o lançamento, o veículo deve permanecer em órbita pelo tempo necessário para a condução de experimentos, sendo depois direcionado à Terra e recuperado em solo. A concepção aerodinâmica é de importância para o vôo em suas diversas fases e deve considerar aspectos relativos à estabilização Aerodinâmica e ao arrasto atmosférico, sendo este último de importância crucial na análise do aquecimento a ser enfrentado. A manobra de retorno inclui considerações sobre as condições atmosféricas e dinâmica de reentrada, devendo ser calculada de forma mais precisa possível. O trabalho proposto avalia estudos da dinâmica de vôo de um satélite recuperável considerando aspectos relativos à determinação orbital com GPS, técnica utilizada com sucesso na CONAE, e seu comportamento aerodinâmico em vôo balístico de retorno, com ênfase em sua fase de reentrada atmosférica. Busca-se otimizar a manobra de reentrada de tal forma que a utilização do sistema GPS garanta minimizar a área de impacto com o solo.

  1. Bruel & Kjær Solutions for Satellite Qualification Testing

    NASA Astrophysics Data System (ADS)

    Wethly, Patrick

    2012-07-01

    Early 2011 the Laboratório de Integração e Testes (LIT) do Instituto Nacional de Pesquisas Espaciais (INPE, http://www.lit.inpe.br/) in Brazil selected Brüel & Kjær as supplier to replace their existing data acquisition and vibration test system for satellite qualification testing. The Brüel & Kjær supplied Satellite Qualification Test System (SQTS) is an integrated total solution for vibration, shock and acoustic fatigue satellite testing. Based on Brüel & Kjær state-of-the-art data acquisition platform LAN-XI the delivered solution integrates different Brüel & Kjær software applications providing a fully integrated solution supporting INPE’s workflow requirements for Satellite Qualification testing. The delivered solutions allows the INPE engineers to seamlessly run the different tasks at hand ensuring ease of use for setup, data acquisition & post processing in relation to the typical satellite qualification tests and is designed to allow multiple INPE engineers and INPE’s client to validate and witness data acquisition in real- time. This paper describes the integrated solutions provided to INPE.

  2. Controle orbital de satélites artificiais com propulsão e uso de gravidade lunar

    NASA Astrophysics Data System (ADS)

    Torres, K. S.; de Almeida Prado, A. F. B.

    2003-08-01

    A redução do custo de combustível de uma manobra é atualmente a grande prioridade de todos os programas espaciais existentes no mundo. As manobras assistidas pela gravidade são uma ótima forma de se contornar o problema pois proporcionam economias com vasto impacto no custo final da missão. Neste trabalho é feito um estudo particular do controle orbital de um satélite artificial da Terra usando a gravidade da Lua. O objetivo é estudar uma técnica econômica para uma mudança de plano de um satélite que está em órbita em volta da Terra. A idéia principal desta abordagem é enviar primeiramente o veículo espacial em direção à Lua usando uma manobra mono-impulsiva para que assim o campo gravitacional da Lua possa fazer a mudança de plano desejada (sem custo de combustível) e só então retornar o veículo aos valores iniciais de semi-eixo e excentricidade usando uma manobra bi-impulsiva tipo Hohmann. Para tanto, é assumido que a espaçonave inicia em uma órbita circular coplanar à órbita da lua em torno da Terra e a meta é colocá-la em uma órbita similar que difere da órbita inicial somente pela inclinação. São usadas equações analíticas baseadas na abordagem Patched Conics para se calcular a variação na velocidade, momento angular, energia e inclinação do veículo espacial que realiza esta manobra. Várias simulações são feitas para se avaliar as economias de combustível envolvidas.

  3. The USAF Phillips Laboratory sodium-sulfur battery technology program: Results and status

    NASA Technical Reports Server (NTRS)

    Rainbow, Marc E.; Somerville, Andrew

    1996-01-01

    Tests performed on NaS batteries are reported. The results of safety and abuse testing, shock and vibration tests, cell failure on warm-up, freeze thaw, overtemperature conditions, electrolyte fracture, overdischarge, and short circuit tests are presented along with GEO and LEO cycle tests and the status of the NaS cell flight tests.

  4. WATER IMPLICATIONS OF BIOFUELS PRODUCTION

    EPA Science Inventory

    Presentation requested by the National Academy of Science (NAS) for a Colloquium on Water Quality Implications of Biofuels Production, to be held at the NAS in Washington, D.C. on July 12, 2007. This presentation will address the influence of ethanol on hydrocarbon plumes and th...

  5. Monitoring the Progress of New American Schools: A Description of Implementing Schools in a Longitudinal Sample.

    ERIC Educational Resources Information Center

    Berends, Mark; Heilbrunn, Jodi; McKelvey, Christopher; Sullivan, Thomas

    A private, nonprofit corporation, New American Schools (NAS) funds the development of designs aimed at transforming entire schools at the elementary and secondary levels. This report describes a large number of NAS sites in their early implementation stages. The report is the first in a series that monitors a longitudinal sample of schools…

  6. An Analysis of the Effects of Net-Centric Operations Using Multi-Agent Adaptive Behavior

    ERIC Educational Resources Information Center

    Calderon-Meza, Guillermo

    2011-01-01

    The National Airspace System (NAS) is a resource managed in the public good. Equity in NAS access, and use for private, commercial and government purposes is coordinated by regulations and made possible by procedures, and technology. Researchers have documented scenarios in which the introduction of new concepts-of-operations and technologies has…

  7. GUIDANCE ON IDENTIFYING THE APPROPRIATE AGE GROUPS FOR ASSESSING CHILDHOOD EXPOSURE AND RISK

    EPA Science Inventory

    The 1993 National Academy of Sciences (NAS) report "Pesticides in the Diets of Infants and Children" highlights important differences between children and adults with respect to risks posed by pesticides. Some of the principles in the NAS report provided the foundation for the Fo...

  8. Numerical Aerodynamic Simulation

    NASA Technical Reports Server (NTRS)

    1989-01-01

    An overview of historical and current numerical aerodynamic simulation (NAS) is given. The capabilities and goals of the Numerical Aerodynamic Simulation Facility are outlined. Emphasis is given to numerical flow visualization and its applications to structural analysis of aircraft and spacecraft bodies. The uses of NAS in computational chemistry, engine design, and galactic evolution are mentioned.

  9. The Novaco Anger Scale--Provocation Inventory (1994 Version) in Dutch Forensic Psychiatric Patients

    ERIC Educational Resources Information Center

    Hornsveld, Ruud H. J.; Muris, Peter; Kraaimaat, Floris W.

    2011-01-01

    We examined the psychometric properties of the Novaco Anger Scale--Provocation Inventory (NAS-PI, 1994 version) in Dutch violent forensic psychiatric patients and secondary vocational students. A confirmatory factor analysis of the subscale structure of the NAS was carried out, reliability was investigated, and relations were calculated between…

  10. 75 FR 57828 - Agency Information Collection Activities: Requests for Comments; Clearance of Renewed Approval of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-22

    ... of Renewed Approval of Information Collection: NAS Data Release Request AGENCY: Federal Aviation... Reduction Act of 1995, FAA invites public comments about our intention to request the Office of Management... evaluate the validity of the user's request for National Airspace (NAS) data from FAA systems and...

  11. 75 FR 13051 - Presumptions of Service Connection for Persian Gulf Service

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-18

    ... warrant a presumption of service connection for any disease discussed in that report. See 66 FR 35702... discussed in that report. 72 FR 48734 (2007). The NAS issued an update on sarin in a report titled ``Gulf... from sarin. 73 FR 42411 (2008). The NAS issued its third report, titled ``Gulf War and Health, Volume...

  12. An Analysis of the Effects of Net-Centric Operations Using Multi-Agent Adaptive Behavior

    ERIC Educational Resources Information Center

    Calderon-Meza, Guillermo

    2011-01-01

    The National Airspace System (NAS) is a resource managed in the public good. Equity in NAS access, and use for private, commercial and government purposes is coordinated by regulations and made possible by procedures, and technology. Researchers have documented scenarios in which the introduction of new concepts-of-operations and technologies has…

  13. "What Does Bowdoin Teach"? A Dialogue between Wood and Klingenstein

    ERIC Educational Resources Information Center

    Wood, Peter; Klingenstein, Tom

    2013-01-01

    This article is an exchange of ideas between Peter Wood, President of the National Association of Scholars (NAS), and Tom Klingerstein, Chairman of the Claremont Institute and NAS Board Director, on the study "What Does Bowdoin Teach? How a Contemporary Liberal Arts College Shapes Students" (by Peter Wood and Michael Toscano). This…

  14. Innate immune sensing of nucleic acids from mycobacteria.

    PubMed

    Yamashiro, Lívia Harumi; Oliveira, Sérgio Costa; Báfica, André

    2014-12-01

    Endosomal and cytosolic receptors engage recognition of mycobacterial-derived nucleic acids (MyNAs). In contrast, virulent mycobacteria may utilize nucleic acid recognition pathways to escape the host immune system. This short review will summarize the mechanisms by which MyNAs are sensed and how they influence host protective responses. PMID:25284681

  15. Fighting the "Damnable Triumph" of Feminism: Battles between Teachers' Unions in Interwar Britain

    ERIC Educational Resources Information Center

    Wilson, Dolly Smith

    2007-01-01

    The interwar decades saw a bitter recruiting war between the NUT (National Union of Teachers), the National Union of Women Teachers (NUWT), and the National Association of Schoolmasters (NAS), which like the NUWT broke away from the NUT in the early 1920s. The NAS opposed the NUT's official policy shift to support equal pay for male and female…

  16. Infant autonomic functioning and neonatal abstinence syndrome

    PubMed Central

    Jansson, Lauren M.; DiPietro, Janet A.; Elko, Andrea; Velez, Martha

    2010-01-01

    Background Neonatal abstinence syndrome (NAS) expression is widely variable among affected infants and the reasons for this variability are largely unknown; mechanisms that predispose infants to NAS expression are not understood. It has been postulated that the regulatory problems of prenatally drug exposed infants are manifested in dysfunctional vagal regulation of autonomic processes. The current study examines whether cardiac vagal tone, an indicator of parasympathetic neuroregulation, provides a marker for autonomic dysregulation subsequently expressed as NAS in prenatally opioid-exposed newborns. Methods Heart period (HP) and cardiac vagal tone (V) were derived from electrocardiogram data collected from 64 methadone-exposed infants on postnatal days 1 and 3. The postpartum NAS course was assessed serially. Results Infants with lower V on day 1 had significantly higher NAS symptomatology on day 3. Boys had more severe NAS symptoms than girls through the first 4 days of life and, among infants receiving pharmacologic treatment for NAS, boys required longer treatment course and hospitalizations. Greater poly-drug exposure, detected through toxicology screening throughout pregnancy, and cocaine use in particular, were associated with lower V and shorter HP (faster heart rate) in newborns. Multiple regression models accounted for 25 to 35% of the variance in NAS symptoms and duration of hospitalization in methadone-exposed infants. Significant predictors included infant sex, SSRI/SNRI use, and cigarette smoking. Conclusions Results support the hypothesis of a biologic vulnerability of autonomic regulatory functioning in methadone-exposed infants and greater male infant vulnerability to maternal methadone use. PMID:20189732

  17. Model development for naphthenic acids ozonation process.

    PubMed

    Al Jibouri, Ali Kamel H; Wu, Jiangning

    2015-02-01

    Naphthenic acids (NAs) are toxic constituents of oil sands process-affected water (OSPW) which is generated during the extraction of bitumen from oil sands. NAs consist mainly of carboxylic acids which are generally biorefractory. For the treatment of OSPW, ozonation is a very beneficial method. It can significantly reduce the concentration of NAs and it can also convert NAs from biorefractory to biodegradable. In this study, a factorial design (2(4)) was used for the ozonation of OSPW to study the influences of the operating parameters (ozone concentration, oxygen/ozone flow rate, pH, and mixing) on the removal of a model NAs in a semi-batch reactor. It was found that ozone concentration had the most significant effect on the NAs concentration compared to other parameters. An empirical model was developed to correlate the concentration of NAs with ozone concentration, oxygen/ozone flow rate, and pH. In addition, a theoretical analysis was conducted to gain the insight into the relationship between the removal of NAs and the operating parameters. PMID:25189805

  18. New American Schools after Six Years.

    ERIC Educational Resources Information Center

    Glennan, Thomas K., Jr.

    This book describes the evolution of New American Schools (NAS) and its strategy for reform during its first 6 years of operation. After a short introduction in chapter 1, chapter 2 outlines the potential contribution of school designs and design-based assistance to education reform, focusing on the nature of NAS designs, the character of…

  19. The Future of the National Association of Scholars

    ERIC Educational Resources Information Center

    Wood, Peter

    2012-01-01

    The National Association of Scholars (NAS) today is focused more than ever on public controversies and on public tools of communication. Where once NAS members were primarily concerned with debates within the academy, now they are equally concerned with debates about the academy. If the topics they address have changed, so too have the means by…

  20. Bold Plans for School Restructuring: The New American Schools Designs.

    ERIC Educational Resources Information Center

    Stringfield, Sam, Ed.; Ross, Steven, M., Ed.; Smith, Lana, Ed.

    In 1991, the New American Schools (NAS) Development Corporation was founded by a group of business and foundation leaders interested in investing in innovative designs for school transformation. This book describes the first 3 years of development and evaluation of 9 NAS whole-school restructuring designs. The designs were very diverse, as were…

  1. MODEL SIMULATION STUDIES OF SCALE-DEPENDENT GAIN IN STREAM NUTRIENT ASSIMILATIVE CAPACITY RESULTING FROM IMPROVING NUTRIENT RETENTION METRICS

    EPA Science Inventory

    Considering the difficulty in measuring restoration success for nonpoint source pollutants, nutrient assimilative capacity (NAS) offers an attractive systems-based metric. Here NAS was defined using an impulse-response model of nitrate fate and transport. Eleven parameters were e...

  2. 78 FR 77705 - Proposed Agency Information Collection Activity: Nonindigenous Aquatic Species Sighting Reporting...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-24

    ....S. Geological Survey Proposed Agency Information Collection Activity: Nonindigenous Aquatic Species... Aquatic Species (NAS) database ( http://nas.er.usgs.gov/ ) functions as a repository and clearinghouse for occurrence information on nonindigenous aquatic species from across the United States. It contains...

  3. Shifts in root-associated microbial communities of Typha latifolia growing in naphthenic acids and relationship to plant health.

    PubMed

    Phillips, Lori A; Armstrong, Sarah A; Headley, John V; Greer, Charles W; Germida, James J

    2010-01-01

    Naphthenic acids (NAs) are a complex mixture of organic acid compounds released during the extraction of crude oil from oil sands operations. The accumulation of toxic NAs in tailings pond water (TPW) is of significant environmental concern, and phytoremediation using constructed wetlands is one remediation option being assessed. Since root-associated microorganisms are an important factor during phytoremediation of organic compounds, this study investigated the impact of NAs on the microbial communities associated with the macrophyte Typha latifolia (cattail). Denaturing gradient gel electrophoresis revealed that the impact of NAs on microbial communities was niche dependent, with endophytic communities being the most stable and bulk water communities being the least stable. The type of NA used was significant to microbial response, with commercial NAs causing greater adverse changes than TPW NAs. In general, plant beneficial bacteria such as diazotrophs were favoured in cattails grown in TPW NAs, while potentially deleterious bacteria such as denitrifying Dechlorospirillum species increased in commercial NA treatments. These findings suggest that NAs may affect plant health by impacting root-associated microbial communities. A better understanding of these impacts may allow researchers to optimize those microbial communities that support plant health, and thus further optimize wetland treatment systems. PMID:21166345

  4. 75 FR 26739 - Notice of Intent To Prepare an Environmental Impact Statement (EIS) for Airfield Operations at...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-12

    ... Operations at Naval Air Station (NAS) Key West, FL and To Announce Public Scoping Meetings AGENCY: Department... questions. FOR FURTHER INFORMATION CONTACT: NAS Key West EIS Project Manager, Naval Facilities Engineering... to support the rapid deployment of naval units; achieve and sustain readiness of squadrons to...

  5. The Novaco Anger Scale--Provocation Inventory (1994 Version) in Dutch Forensic Psychiatric Patients

    ERIC Educational Resources Information Center

    Hornsveld, Ruud H. J.; Muris, Peter; Kraaimaat, Floris W.

    2011-01-01

    We examined the psychometric properties of the Novaco Anger Scale--Provocation Inventory (NAS-PI, 1994 version) in Dutch violent forensic psychiatric patients and secondary vocational students. A confirmatory factor analysis of the subscale structure of the NAS was carried out, reliability was investigated, and relations were calculated between…

  6. Coordination between carbon and nitrogen metabolism in nitrogen fixing bean nodules

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A cDNA clone of asparagine synthetase (AS) called PvNAS2 and two different cDNA clones of PvNADH-GOGAT were isolated from bean nodules. Southern blot analysis indicated that a small gene family encodes AS. Northern analysis demonstrated that PvNAS2 expression is induced in nodules during the early d...

  7. Making the Case for New Research to Support the Integration of Small Unmanned Aircraft Systems into the National Airspace System

    NASA Technical Reports Server (NTRS)

    McAdaragh, Raymon M.; Comstock, James R., Jr.; Ghatas, Rania W.; Burdette, Daniel W.; Trujillo, Anna C.

    2014-01-01

    This paper describes the current state of sUAS regulation, their technical capabilities and the latest technologies that will allow for sUAS NAS integration. The research that is needed to demonstrate sUAS NAS integration capability is identified, and recommendations for conducting this necessary research are suggested.

  8. The Future of the National Association of Scholars

    ERIC Educational Resources Information Center

    Wood, Peter

    2012-01-01

    The National Association of Scholars (NAS) today is focused more than ever on public controversies and on public tools of communication. Where once NAS members were primarily concerned with debates within the academy, now they are equally concerned with debates about the academy. If the topics they address have changed, so too have the means by…

  9. Decisionmaking, Transitions, and Resilient Futures

    SciTech Connect

    Moss, Richard H.; Lane, Meredith A.

    2012-08-01

    The article describes the focus of research in the social sciences on environmental change, describing studies on adaptation and mitigation. It is the first of 5 articles in the NAS quarterly journal IS&T on the occasion of the launch of a new Board at the NAS chaired by the author.

  10. Odor detection thresholds of naphthenic acids from commercial sources and oil sands process-affected water.

    PubMed

    Edge, Kristyn; Barona, Brenda; Young, Rozlyn F; Fedorak, Phillip M; Wismer, Wendy V

    2010-11-01

    Naphthenic acids (NAs) occur naturally in various petroleums and in oil sands tailings waters and have been implicated as potential fish tainting compounds. In this study, trained sensory panels and the general population from a university were used to determine the odor detection thresholds of two commercial NAs preparations (Acros and Merichem) and of NAs extracted from an oil sands experimental reclamation pond (Pond 9). Using the three-alternative forced choice method, a concentration series of NAs were presented to the sensory panels in phosphate buffer (pH 8) and in steamed fish (Sander vitreus). In buffer, the odor detection thresholds of Acros, Merichem and Pond 9 NAs, as evaluated by the trained panelists, were 1.5, 0.04, and 1.0 mg L(-1), respectively. Only the detection threshold for the Merichem NAs was significantly different (p<0.01) than the other two sources. Based on the general population assessments, all three odor detection thresholds were significantly different from one another; 4.8, 0.2, and 2.5 mg L(-1) for Acros, Merichem, and Pond 9 NAs, respectively (p<0.01). The odor detection thresholds of Merichem and Pond 9 NAs in steamed fish were 0.6 and 12 mg kg(-1), respectively and were significantly different from each other (p<0.01). The detection threshold of Acros NAs was estimated to be >21 mg kg(-1). For the steamed fish evaluations, the odor descriptors of all three of the NAs preparations was given as chemical in nature (Acros: oil, plastic; Merichem: gasoline; Pond 9: gasoline, tar). Exposure of live rainbow trout to a non-lethal concentration of Merichem NAs (3 mg L(-1) for 10 d) imparted an odor to the fish flesh. Analyses of the three NAs preparations by gas chromatography-mass spectrometry showed that each had a unique distribution of acids. We conclude that the source of the NAs is important when interpreting odor threshold data and that the two commercial preparations of NAs that were tested do not represent oil sands waters' tainting potential. PMID:20801486

  11. Transcriptional responses of earthworm (Eisenia fetida) exposed to naphthenic acids in soil.

    PubMed

    Wang, Jie; Cao, Xiaofeng; Sun, Jinhua; Chai, Liwei; Huang, Yi; Tang, Xiaoyan

    2015-09-01

    In this study, earthworms (Eisenia fetida) were exposed to commercial NAs contaminated soil, and changes in the levels of reactive oxygen species (ROS) and gene expressions of their defense system were monitored. The effects on the gene expression involved in reproduction and carcinogenesis were also evaluated. Significant increases in ROS levels was observed in NAs exposure groups, and the superoxide dismutase (SOD) and catalase (CAT) genes were both up-regulated at low and medium exposure doses, which implied NAs might exert toxicity by oxidative stress. The transcription of CRT and HSP70 coincided with oxidative stress, which implied both chaperones perform important functions in the protection against oxidative toxicity. The upregulation of TCTP gene indicated a potential adverse effect of NAs to terrestrial organisms through induction of carcinogenesis, and the downregulation of ANN gene indicated that NAs might potentially result in deleterious reproduction effects. PMID:25984985

  12. A study of mixed group-V nitrides grown by gas-source molecular beam epitaxy using a nitrogen radical beam source

    SciTech Connect

    Bi, W.G.; Tu, C.W.; Mathes, D.; Hull, R.

    1997-12-31

    The authors report a study of N incorporation in GaAs and InP by gas-source molecular beam epitaxy using a N radical beam source. For GaNAs grown at high temperatures, phase separation was observed, as evidenced from the formation of cubic GaN aside from GaNAs. By lowering the growth temperature, however, GaNAs alloys with N as high as 14.8% have been obtained without showing any phase separation. For InNP, no phase separation was observed in the temperature range studied (310--420 C). Contrary to GaNAs, incorporating N in InP is very difficult, with only less than 1% N being achieved. Optical absorption measurement reveals strong red shift of bandgap energy with direct-bandgap absorption. However, no semimetallic region seems to exist for GaNAs and a composition, dependent bowing parameter has been observed.

  13. Environmental, health, and safety issues of sodium-sulfur batteries for electric and hybrid vehicles. Volume 1, Cell and battery safety

    SciTech Connect

    Ohi, J.M.

    1992-09-01

    This report is the first of four volumes that identify and assess the environmental, health, and safety issues involved in using sodium-sulfur (Na/S) battery technology as the energy source in electric and hybrid vehicles that may affect the commercialization of Na/S batteries. This and the other reports on recycling, shipping, and vehicle safety are intended to help the Electric and Hybrid Propulsion Division of the Office of Transportation Technologies in the US Department of Energy (DOE/EHP) determine the direction of its research, development, and demonstration (RD&D) program for Na/S battery technology. The reports review the status of Na/S battery RD&D and identify potential hazards and risks that may require additional research or that may affect the design and use of Na/S batteries. This volume covers cell design and engineering as the basis of safety for Na/S batteries and describes and assesses the potential chemical, electrical, and thermal hazards and risks of Na/S cells and batteries as well as the RD&D performed, under way, or to address these hazards and risks. The report is based on a review of the literature and on discussions with experts at DOE, national laboratories and agencies, universities, and private industry. Subsequent volumes will address environmental, health, and safety issues involved in shipping cells and batteries, using batteries to propel electric vehicles, and recycling and disposing of spent batteries. The remainder of this volume is divided into two major sections on safety at the cell and battery levels. The section on Na/S cells describes major component and potential failure modes, design, life testing and failure testing, thermal cycling, and the safety status of Na/S cells. The section on batteries describes battery design, testing, and safety status. Additional EH&S information on Na/S batteries is provided in the appendices.

  14. Environmental, health, and safety issues of sodium-sulfur batteries for electric and hybrid vehicles

    SciTech Connect

    Ohi, J.M.

    1992-09-01

    This report is the first of four volumes that identify and assess the environmental, health, and safety issues involved in using sodium-sulfur (Na/S) battery technology as the energy source in electric and hybrid vehicles that may affect the commercialization of Na/S batteries. This and the other reports on recycling, shipping, and vehicle safety are intended to help the Electric and Hybrid Propulsion Division of the Office of Transportation Technologies in the US Department of Energy (DOE/EHP) determine the direction of its research, development, and demonstration (RD D) program for Na/S battery technology. The reports review the status of Na/S battery RD D and identify potential hazards and risks that may require additional research or that may affect the design and use of Na/S batteries. This volume covers cell design and engineering as the basis of safety for Na/S batteries and describes and assesses the potential chemical, electrical, and thermal hazards and risks of Na/S cells and batteries as well as the RD D performed, under way, or to address these hazards and risks. The report is based on a review of the literature and on discussions with experts at DOE, national laboratories and agencies, universities, and private industry. Subsequent volumes will address environmental, health, and safety issues involved in shipping cells and batteries, using batteries to propel electric vehicles, and recycling and disposing of spent batteries. The remainder of this volume is divided into two major sections on safety at the cell and battery levels. The section on Na/S cells describes major component and potential failure modes, design, life testing and failure testing, thermal cycling, and the safety status of Na/S cells. The section on batteries describes battery design, testing, and safety status. Additional EH S information on Na/S batteries is provided in the appendices.

  15. Effect of N-Acetylserotonin on Intestinal Recovery Following Intestinal Ischemia-Reperfusion Injury in a Rat.

    PubMed

    Shahar, Yoav Ben; Sukhotnik, Igor; Bitterman, Nir; Pollak, Yulia; Bejar, Jacob; Chepurov, Dmitriy; Coran, Arnold; Bitterman, Arie

    2016-02-01

    Objective?N-acetylserotonin (NAS) is a naturally occurring chemical intermediate in the biosynthesis of melatonin. Extensive studies in various experimental models have established that treatment with NAS significantly protects heart and kidney injury from ischemia-reperfusion (IR). The purpose of the present study was to examine the effect of NAS on intestinal recovery and enterocyte turnover after intestinal IR injury in rats. Methods?Male Sprague-Dawley rats were divided into four experimental groups: (1) Sham rats underwent laparotomy, (2) sham-NAS rats underwent laparotomy and were treated with intraperitoneal (IP) NAS (20 mg/kg); (3) IR rats underwent occlusion of both superior mesenteric artery and portal vein for 30 minutes, followed by 48 hours of reperfusion, and (4) IR-NAS rats underwent IR and were treated with IP NAS (20 mg/kg) immediately before abdominal closure. Intestinal structural changes, Park injury score, enterocyte proliferation, and enterocyte apoptosis were determined 24 hours following IR. The expression of Bax, Bcl-2, p-ERK, and caspase-3 in the intestinal mucosa was determined using real-time polymerase chain reaction, Western blot, and immunohistochemistry. A nonparametric Kruskal-Wallis analysis of variance test was used for statistical analysis with p less than 0.05 considered statistically significant. Results?Treatment with NAS resulted in a significant increase in mucosal weight in jejunum and ileum, villus height in the ileum, and crypt depth in jejunum and ileum compared with IR animals. IR-NAS rats also had a significantly proliferation rates as well as a lower apoptotic index in jejunum and ileum which was accompanied by higher Bcl-2 levels compared with IR animals. Conclusions?Treatment with NAS prevents gut mucosal damage and inhibits programmed cell death following intestinal IR in a rat. PMID:26378484

  16. Maternal opioid dose is associated with neonatal abstinence syndrome in children born to women with sickle cell disease.

    PubMed

    Shirel, Tyler; Hubler, Collin P; Shah, Rena; Mager, Amy B; Koch, Kathryn L; Sheth, Darshita; Uhing, Michael R; Jones, Cresta W; Field, Joshua J

    2016-06-01

    The objective of this study was to test the hypothesis that higher daily opioid dose is associated with the presence and severity of neonatal abstinence syndrome (NAS) in pregnant women with sickle cell disease (SCD). This was a retrospective study of pregnant women with SCD who required opioids. NAS was evaluated using the Finnegan scoring system and classified as none, mild, and severe. Severe NAS was defined as a Finnegan score ≥ 8 on 3 consecutive tests. Thirty-four pregnancies were examined in 30 women with SCD. Higher daily morphine dose was associated with a higher percentage of days in the hospital during pregnancy (P < 0.001). Hospital days contributed disproportionately to daily morphine dose as larger amounts of opioids were administered in the hospital compared to home (P = 0.002). Median maternal oral morphine dose was 416 mg for infants with severe NAS compared with 139 mg for those with mild NAS (P = 0.04). For infants with no NAS, median maternal morphine was 4 mg, significantly less than those with mild NAS (P < 0.001). Infants born to women who used on average >200 mg/day of oral morphine equivalent in the last month of pregnancy had a 13-fold increased risk of severe NAS compared with those who used <200 mg/day. These data demonstrate that higher median daily opioid dose is associated with progressively more severe NAS in pregnant women with SCD. Strategies to decrease pain and avoid hospitalizations are needed to reduce opioid use and NAS. Am. J. Hematol. 91:416-419, 2016. © 2016 Wiley Periodicals, Inc. PMID:26799428

  17. Kushenin Combined with Nucleos(t)ide Analogues for Chronic Hepatitis B: A Systematic Review and Meta-Analysis

    PubMed Central

    Chen, Zhe; Ma, Xiao; Zhao, Yanling; Wang, Jiabo; Zhang, Yaming; Zhu, Yun; Wang, Lifu; Chen, Chang; Wei, Shizhang; Yang, Zhirui; Gong, Man; Shen, Honghui; Bai, Zhaofang; Guo, Yuming; Niu, Ming; Xiao, Xiaohe

    2015-01-01

    Objective. To evaluate the efficacy and safety of Kushenin (KS) combined with nucleoside analogues (NAs) for chronic hepatitis B (CHB). Methods. Randomized controlled trials (RCTs) of KS combined with NAs for CHB were identified through 7 databases. Frequencies of loss of serum HBeAg, HBeAg seroconversion, undetectable serum HBV-DNA, ALT normalization, and adverse events at 48 weeks were abstracted by two reviewers. The Cochrane software was performed to assess the risk of bias in the included trials. Data were analyzed with Review Manager 5.3 software. Results. 18 RCTs involving 1684 subjects with CHB were included in the analysis. KS combined with NAs including lamivudine (LAM), entecavir (ETV), adefovir dipivoxil (ADV), and telbivudine (TLV) showed different degree of improvement in CHB indices. KS combined with NAs increased the frequency of loss of serum HBeAg, HBeAg seroconversion, undetectable HBV-DNA levels, and ALT normalization compared with single agents. It also decreased serum ALT and AST level after one-year treatment. However, KS combined with TLV did not show a significant difference in CHB indices. The side-effects of KS combined with NAs were light and of low frequency. Conclusion. KS combined with NAs improves the efficacy of NAs in CHB. PMID:26347789

  18. Extrahepatic effects of nucleoside and nucleotide analogues in chronic hepatitis B treatment.

    PubMed

    Fung, James; Seto, Wai-Kay; Lai, Ching-Lung; Yuen, Man-Fung

    2014-03-01

    Oral nucleoside/nucleotide analogues (NAs) are the mainstay of therapy for patients with chronic hepatitis B and are generally well tolerated. Despite this, the safety profile of NAs is of paramount importance since the majority of patients will require long-term treatment. All NAs can potentially affect human DNA polymerase with decrease in mitochondrial DNA, leading to manifestations of mitochondrial toxicity. As a class effect, therefore, NAs can potentially cause extrahepatic conditions, such as myopathy, nephropathy, neuropathy, and lactic acidosis. Indeed, effects on muscles, including myopathy and creatine kinase elevations, have been described with clevudine and telbivudine use. Both adefovir and tenofovir are associated with dose-dependent nephropathy, predominantly affecting the proximal renal tubules. Neuropathy appears to be rare, and most commonly reported in patients receiving combination therapy with telbivudine and interferon. Increased risk of lactic acidosis has also been described for those with impaired liver and renal function taking entecavir. Loss of bone mineral density and hypophosphatemia have been described with the use of NAs, although the overwhelming studies have been with human immunodeficiency virus-infected patients. However, not all extrahepatic effects are detrimental. Recent evidence has suggested a potential renal beneficial effect with the use of telbivudine. The effect of NAs on pregnancy appears to be minimal for all NAs, with telbivudine and tenofovir having a more favorable category B rating. Ongoing pharmacovigilance is essential to identify new and monitor existing extrahepatic effects associated with NA use. PMID:24372662

  19. Internal-Modified Dithiol DNA-Directed Au Nanoassemblies: Geometrically Controlled Self-Assembly and Quantitative Surface-Enhanced Raman Scattering Properties.

    PubMed

    Yan, Yuan; Shan, Hangyong; Li, Min; Chen, Shu; Liu, Jianyu; Cheng, Yanfang; Ye, Cui; Yang, Zhilin; Lai, Xuandi; Hu, Jianqiang

    2015-01-01

    In this work, a hierarchical DNA-directed self-assembly strategy to construct structure-controlled Au nanoassemblies (NAs) has been demonstrated by conjugating Au nanoparticles (NPs) with internal-modified dithiol single-strand DNA (ssDNA) (Au-B-A or A-B-Au-B-A). It is found that the dithiol-ssDNA-modified Au NPs and molecule quantity of thiol-modified ssDNA grafted to Au NPs play critical roles in the assembly of geometrically controlled Au NAs. Through matching Au-DNA self-assembly units, geometrical structures of the Au NAs can be tailored from one-dimensional (1D) to quasi-2D and 2D. Au-B-A conjugates readily give 1D and quasi-2D Au NAs while 2D Au NAs can be formed by A-B-Au-B-A building blocks. Surface-enhanced Raman scattering (SERS) measurements and 3D finite-difference time domain (3D-FDTD) calculation results indicate that the geometrically controllable Au NAs have regular and linearly "hot spots"-number-depended SERS properties. For a certain number of NPs, the number of "hot spots" and accordingly enhancement factor of Au NAs can be quantitatively evaluated, which open a new avenue for quantitative analysis based on SERS technique. PMID:26581251

  20. Internal-Modified Dithiol DNA–Directed Au Nanoassemblies: Geometrically Controlled Self–Assembly and Quantitative Surface–Enhanced Raman Scattering Properties

    NASA Astrophysics Data System (ADS)

    Yan, Yuan; Shan, Hangyong; Li, Min; Chen, Shu; Liu, Jianyu; Cheng, Yanfang; Ye, Cui; Yang, Zhilin; Lai, Xuandi; Hu, Jianqiang

    2015-11-01

    In this work, a hierarchical DNA–directed self–assembly strategy to construct structure–controlled Au nanoassemblies (NAs) has been demonstrated by conjugating Au nanoparticles (NPs) with internal–modified dithiol single-strand DNA (ssDNA) (Au–B–A or A–B–Au–B–A). It is found that the dithiol–ssDNA–modified Au NPs and molecule quantity of thiol–modified ssDNA grafted to Au NPs play critical roles in the assembly of geometrically controlled Au NAs. Through matching Au–DNA self–assembly units, geometrical structures of the Au NAs can be tailored from one–dimensional (1D) to quasi–2D and 2D. Au–B–A conjugates readily give 1D and quasi–2D Au NAs while 2D Au NAs can be formed by A–B–Au–B–A building blocks. Surface-enhanced Raman scattering (SERS) measurements and 3D finite–difference time domain (3D-FDTD) calculation results indicate that the geometrically controllable Au NAs have regular and linearly “hot spots”–number–depended SERS properties. For a certain number of NPs, the number of “hot spots” and accordingly enhancement factor of Au NAs can be quantitatively evaluated, which open a new avenue for quantitative analysis based on SERS technique.

  1. Internal-Modified Dithiol DNA–Directed Au Nanoassemblies: Geometrically Controlled Self–Assembly and Quantitative Surface–Enhanced Raman Scattering Properties

    PubMed Central

    Yan, Yuan; Shan, Hangyong; Li, Min; Chen, Shu; Liu, Jianyu; Cheng, Yanfang; Ye, Cui; Yang, Zhilin; Lai, Xuandi; Hu, Jianqiang

    2015-01-01

    In this work, a hierarchical DNA–directed self–assembly strategy to construct structure–controlled Au nanoassemblies (NAs) has been demonstrated by conjugating Au nanoparticles (NPs) with internal–modified dithiol single-strand DNA (ssDNA) (Au–B–A or A–B–Au–B–A). It is found that the dithiol–ssDNA–modified Au NPs and molecule quantity of thiol–modified ssDNA grafted to Au NPs play critical roles in the assembly of geometrically controlled Au NAs. Through matching Au–DNA self–assembly units, geometrical structures of the Au NAs can be tailored from one–dimensional (1D) to quasi–2D and 2D. Au–B–A conjugates readily give 1D and quasi–2D Au NAs while 2D Au NAs can be formed by A–B–Au–B–A building blocks. Surface-enhanced Raman scattering (SERS) measurements and 3D finite–difference time domain (3D-FDTD) calculation results indicate that the geometrically controllable Au NAs have regular and linearly “hot spots”–number–depended SERS properties. For a certain number of NPs, the number of “hot spots” and accordingly enhancement factor of Au NAs can be quantitatively evaluated, which open a new avenue for quantitative analysis based on SERS technique. PMID:26581251

  2. Harnessing oil sands microbial communities for use in ex situ naphthenic acid bioremediation.

    PubMed

    Demeter, Marc A; Lemire, Joe; George, Iain; Yue, Gordon; Ceri, Howard; Turner, Raymond J

    2014-02-01

    The caustic hot water extraction process used to release bitumen from the Alberta oil sands generates large volumes of tailings waste, or oil sands process water (OSPW). OSPW contains several components of environmental concern including diluents, polyaromatic hydrocarbons, heavy metals, and naphthenic acids (NAs); the latter are of particular concern as they are acutely toxic to aquatic organisms and mammals. Studies have demonstrated that the naturally occurring OSPW bacteria are capable of metabolizing the NAs. However, this in situ process takes place over hundreds of years, and is incomplete, leaving a recalcitrant fraction of NAs intact. In this study we explore options for recovering and harnessing the naturally occurring OSPW bacteria for potential future use in an aerobic ex situ OSPW treatment system. Here we evaluate our recovered microbes on their ability to degrade two model NAs, cyclohexane carboxylic acid and cyclohexane acetic acid. Using OSPW as a source for a bacterial inoculum, we were able to compare single and multispecies OSPW cultures, grown as either a biofilm, or as a planktonic suspension. Furthermore, we examined the effect of available nutrients on the ability of these cultures to degrade NAs. All biofilms were grown using the Calgary Biofilm Device. GC-MS, and GC-FID reveal that multispecies biofilm and planktonic cultures are each capable of degrading both NAs; a trait not observed for single species cultures. Moreover, complementary carbon sources have a tangible effect on the ability of the cultures to initiate the degradation of the NAs. PMID:24325800

  3. Effect of ozonation on the naphthenic acids' speciation and toxicity of pH-dependent organic extracts of oil sands process-affected water.

    PubMed

    Klamerth, Nikolaus; Moreira, Jesús; Li, Chao; Singh, Arvinder; McPhedran, Kerry N; Chelme-Ayala, Pamela; Belosevic, Miodrag; Gamal El-Din, Mohamed

    2015-02-15

    The presence of naphthenic acids (NAs) and other organic constituents in oil sands process-affected water (OSPW) stored in tailings ponds, poses a serious environmental threat due to their potential toxicity to aquatic organisms and wild life. In this work, four fractions of OSPW, extracted by dichloromethane at different pHs, were ozonated to determine the ozone impact on NAs degradation. Extracts distributions showed that high carbon number NAs (14-22) were associated with higher pH fractions (pH>7) and smaller carbon number NAs (7-13) with lower pH fractions (pH?7). Extracts showed similar hydrogen deficiency (Z-number) patterns centered on Z=6. Analysis of the speciation of NAs and oxidized NAs in the four fractions showed that ozonation degraded most NAs (55% to 98%). Despite the high degradation levels, there was still significant toxicity of the fractions toward goldfish macrophages and measurable toxicity toward Vibrio fischeri. The toxicity of such a complex matrix as OSPW may be attributed to other organic compounds and degradation by-products not currently detected. Thus, there is a need to elucidate which compounds are responsible for the remaining OSPW toxicity and to determine if combined processes, such as ozonation followed by biological treatment, are able to completely detoxify OSPW. This work is taking the first steps into this direction, narrowing down the range of compounds which might be responsible for the toxicity. PMID:25460940

  4. Ozonation of oil sands process-affected water accelerates microbial bioremediation.

    PubMed

    Martin, Jonathan W; Barri, Thaer; Han, Xiumei; Fedorak, Phillip M; El-Din, Mohamed Gamal; Perez, Leonidas; Scott, Angela C; Jiang, Jason Tiange

    2010-11-01

    Ozonation can degrade toxic naphthenic acids (NAs) in oil sands process-affected water (OSPW), but even after extensive treatment a residual NA fraction remains. Here we hypothesized that mild ozonation would selectively oxidize the most biopersistent NA fraction, thereby accelerating subsequent NA biodegradation and toxicity removal by indigenous microbes. OSPW was ozonated to achieve approximately 50% and 75% NA degradation, and the major ozonation byproducts included oxidized NAs (i.e., hydroxy- or keto-NAs). However, oxidized NAs are already present in untreated OSPW and were shown to be formed during the microbial biodegradation of NAs. Ozonation alone did not affect OSPW toxicity, based on Microtox; however, there was a significant acceleration of toxicity removal in ozonated OSPW following inoculation with native microbes. Furthermore, all residual NAs biodegraded significantly faster in ozonated OSPW. The opposite trend was found for ozonated commercial NAs, which are known to contain no significant biopersistent fraction. Thus, we suggest that ozonation preferentially degraded the most biopersistent OSPW NA fraction, and that ozonation is complementary to the biodegradation capacity of microbial populations in OSPW. The toxicity of ozonated OSPW to higher organisms needs to be assessed, but there is promise that this technique could be applied to accelerate the bioremediation of large volumes of OSPW in Northern Alberta, Canada. PMID:20929252

  5. Application of patterned growth of aligned zinc oxide nanoarrays by mirocontact printing in quantum dots-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Deng, Jianping; Wang, Minqiang; Yang, Zhi; Liu, Jing; Sun, Zhongwang; Song, Xiaohui

    2015-04-01

    This paper describes a simple method for patterned growth of ZnO nanoarrays (NAs) that is based on a combination of the microcontact printing process for patterning ZnO seed films and the low-temperature hydrothermal approach for depositing ZnO NAs. The patterned ZnO seed films were achieved via printing patterned TiO2 sol on ZnO seed films. It is found that the pattern quality is mainly affected by the viscosity of TiO2 ink and the pressure including value and direction. To assess the possibility of patterned ZnO NAs applied to devices, the patterned ZnO NAs were used as light scattering layer in CdSe-sensitized solar cells. The diffuse-reflection, absorption and transmission spectra show that the patterned ZnO NAs greatly enhance the light scattering and absorbance in the visible range. The enhancement of cell performance is attributed to the patterned ZnO NAs: 1) multiple-light scattering improves the light absorbance, and 2) NAs with high electron mobility facilitate the electron collection.

  6. Impact of ozonation on naphthenic acids speciation and toxicity of oil sands process-affected water to Vibrio fischeri and mammalian immune system.

    PubMed

    Wang, Nan; Chelme-Ayala, Pamela; Perez-Estrada, Leonidas; Garcia-Garcia, Erick; Pun, Jonathan; Martin, Jonathan W; Belosevic, Miodrag; Gamal El-Din, Mohamed

    2013-06-18

    Oil sands process-affected water (OSPW) is the water contained in tailings impoundment structures in oil sands operations. There are concerns about the environmental impacts of the release of OSPW because of its toxicity. In this study, ozonation followed by biodegradation was used to remediate OSPW. The impacts of the ozone process evolution on the naphthenic acids (NAs) speciation and acute toxicity were evaluated. Ion-mobility spectrometry (IMS) was used to preliminarily separate isomeric and homologous species. The results showed limited effects of the ozone reactor size on the treatment performance in terms of contaminant removal. In terms of NAs speciation, high reactivity of NAs with higher number of carbons and rings was only observed in a region of high reactivity (i.e., utilized ozone dose lower than 50 mg/L). It was also found that nearly 0.5 mg/L total NAs was oxidized per mg/L of utilized ozone dose, at utilized ozone doses lower than 50 mg/L. IMS showed that ozonation was able to degrade NAs, oxidized NAs, and sulfur/nitrogenated NAs. Complete removal of toxicity toward Vibrio fischeri was achieved after ozonation followed by 28-day biodegradation period. In vitro and in vivo assays indicated that ozonation reduced the OSPW toxicity to mice. PMID:23683033

  7. Amelioration of binge eating by nucleus accumbens shell deep brain stimulation in mice involves D2 receptor modulation.

    PubMed

    Halpern, Casey H; Tekriwal, Anand; Santollo, Jessica; Keating, Jeffrey G; Wolf, John A; Daniels, Derek; Bale, Tracy L

    2013-04-24

    Hedonic overconsumption contributing to obesity involves altered activation within the mesolimbic dopamine system. Dysregulation of dopamine signaling in the nucleus accumbens shell (NAS) has been implicated in reward-seeking behaviors, such as binge eating, which contributes to treatment resistance in obesity (Wise, 2012). Direct modulation of the NAS with deep brain stimulation (DBS), a surgical procedure currently under investigation in humans for the treatment of major depression, obsessive-compulsive disorder, and addiction, may also be effective in ameliorating binge eating. Therefore, we examined the ability of DBS of the NAS to block this behavior in mice. c-Fos immunoreactivity was assessed as a marker of DBS-mediated neuronal activation. NAS DBS was found to reduce binge eating and increased c-Fos levels in this region. DBS of the dorsal striatum had no influence on this behavior, demonstrating anatomical specificity for this effect. The dopamine D2 receptor antagonist, raclopride, attenuated the action of DBS, whereas the D1 receptor antagonist, SCH-23390, was ineffective, suggesting that dopamine signaling involving D2 receptors underlies the effect of NAS DBS. To determine the potential translational relevance to the obese state, chronic NAS DBS was also examined in diet-induced obese mice and was found to acutely reduce caloric intake and induce weight loss. Together, these findings support the involvement of the mesolimbic dopamine pathways in the hedonic mechanisms contributing to obesity, and the efficacy of NAS DBS to modulate this system. PMID:23616522

  8. An integrated biochemical system for nitrate assimilation and nitric oxide detoxification in Bradyrhizobium japonicum

    PubMed Central

    Cabrera, Juan J.; Salas, Ana; Torres, María J.; Bedmar, Eulogio J.; Richardson, David J.; Gates, Andrew J.; Delgado, María J.

    2015-01-01

    Rhizobia are recognized to establish N2-fixing symbiotic interactions with legume plants. Bradyrhizobium japonicum, the symbiont of soybeans, can denitrify and grow under free-living conditions with nitrate (NO3−) or nitrite (NO2−) as sole nitrogen source. Unlike related bacteria that assimilate NO3−, genes encoding the assimilatory NO3− reductase (nasC) and NO2− reductase (nirA) in B. japonicum are located at distinct chromosomal loci. The nasC gene is located with genes encoding an ABC-type NO3− transporter, a major facilitator family NO3−/NO2− transporter (NarK), flavoprotein (Flp) and single-domain haemoglobin (termed Bjgb). However, nirA clusters with genes for a NO3−/NO2−-responsive regulator (NasS-NasT). In the present study, we demonstrate NasC and NirA are both key for NO3− assimilation and that growth with NO3−, but not NO2− requires flp, implying Flp may function as electron donor to NasC. In addition, bjgb and flp encode a nitric oxide (NO) detoxification system that functions to mitigate cytotoxic NO formed as a by-product of NO3− assimilation. Additional experiments reveal NasT is required for NO3−-responsive expression of the narK-bjgb-flp-nasC transcriptional unit and the nirA gene and that NasS is also involved in the regulatory control of this novel bipartite assimilatory NO3−/NO2− reductase pathway. PMID:26564204

  9. Environmental, health, and safety issues of sodium-sulfur batteries for electric and hybrid vehicles

    SciTech Connect

    Corbus, D.

    1992-09-01

    Recycling and disposal of spent sodium-sulfur (Na/S) batteries are important issues that must be addressed as part of the commercialization process of Na/S battery-powered electric vehicles. The use of Na/S batteries in electric vehicles will result in significant environmental benefits, and the disposal of spent batteries should not detract from those benefits. In the United States, waste disposal is regulated under the Resource Conservation and Recovery Act (RCRA). Understanding these regulations will help in selecting recycling and disposal processes for Na/S batteries that are environmentally acceptable and cost effective. Treatment processes for spent Na/S battery wastes are in the beginning stages of development, so a final evaluation of the impact of RCRA regulations on these treatment processes is not possible. The objectives of tills report on battery recycling and disposal are as follows: Provide an overview of RCRA regulations and requirements as they apply to Na/S battery recycling and disposal so that battery developers can understand what is required of them to comply with these regulations; Analyze existing RCRA regulations for recycling and disposal and anticipated trends in these regulations and perform a preliminary regulatory analysis for potential battery disposal and recycling processes. This report assumes that long-term Na/S battery disposal processes will be capable of handling large quantities of spent batteries. The term disposal includes treatment processes that may incorporate recycling of battery constituents. The environmental regulations analyzed in this report are limited to US regulations. This report gives an overview of RCRA and discusses RCRA regulations governing Na/S battery disposal and a preliminary regulatory analysis for Na/S battery disposal.

  10. Environmental, health, and safety issues of sodium-sulfur batteries for electric and hybrid vehicles. Volume 2, Battery recycling and disposal

    SciTech Connect

    Corbus, D.

    1992-09-01

    Recycling and disposal of spent sodium-sulfur (Na/S) batteries are important issues that must be addressed as part of the commercialization process of Na/S battery-powered electric vehicles. The use of Na/S batteries in electric vehicles will result in significant environmental benefits, and the disposal of spent batteries should not detract from those benefits. In the United States, waste disposal is regulated under the Resource Conservation and Recovery Act (RCRA). Understanding these regulations will help in selecting recycling and disposal processes for Na/S batteries that are environmentally acceptable and cost effective. Treatment processes for spent Na/S battery wastes are in the beginning stages of development, so a final evaluation of the impact of RCRA regulations on these treatment processes is not possible. The objectives of tills report on battery recycling and disposal are as follows: Provide an overview of RCRA regulations and requirements as they apply to Na/S battery recycling and disposal so that battery developers can understand what is required of them to comply with these regulations; Analyze existing RCRA regulations for recycling and disposal and anticipated trends in these regulations and perform a preliminary regulatory analysis for potential battery disposal and recycling processes. This report assumes that long-term Na/S battery disposal processes will be capable of handling large quantities of spent batteries. The term disposal includes treatment processes that may incorporate recycling of battery constituents. The environmental regulations analyzed in this report are limited to US regulations. This report gives an overview of RCRA and discusses RCRA regulations governing Na/S battery disposal and a preliminary regulatory analysis for Na/S battery disposal.

  11. An integrated biochemical system for nitrate assimilation and nitric oxide detoxification in Bradyrhizobium japonicum.

    PubMed

    Cabrera, Juan J; Salas, Ana; Torres, María J; Bedmar, Eulogio J; Richardson, David J; Gates, Andrew J; Delgado, María J

    2016-02-01

    Rhizobia are recognized to establish N2-fixing symbiotic interactions with legume plants. Bradyrhizobium japonicum, the symbiont of soybeans, can denitrify and grow under free-living conditions with nitrate (NO3 (-)) or nitrite (NO2 (-)) as sole nitrogen source. Unlike related bacteria that assimilate NO3 (-), genes encoding the assimilatory NO3 (-) reductase (nasC) and NO2 (-) reductase (nirA) in B. japonicum are located at distinct chromosomal loci. The nasC gene is located with genes encoding an ABC-type NO3 (-) transporter, a major facilitator family NO3 (-)/NO2 (-) transporter (NarK), flavoprotein (Flp) and single-domain haemoglobin (termed Bjgb). However, nirA clusters with genes for a NO3 (-)/NO2 (-)-responsive regulator (NasS-NasT). In the present study, we demonstrate NasC and NirA are both key for NO3 (-) assimilation and that growth with NO3 (-), but not NO2 (-) requires flp, implying Flp may function as electron donor to NasC. In addition, bjgb and flp encode a nitric oxide (NO) detoxification system that functions to mitigate cytotoxic NO formed as a by-product of NO3 (-) assimilation. Additional experiments reveal NasT is required for NO3 (-)-responsive expression of the narK-bjgb-flp-nasC transcriptional unit and the nirA gene and that NasS is also involved in the regulatory control of this novel bipartite assimilatory NO3 (-)/NO2 (-) reductase pathway. PMID:26564204

  12. The NYC native air sampling pilot project: using HVAC filter data for urban biological incident characterization.

    PubMed

    Ackelsberg, Joel; Leykam, Frederic M; Hazi, Yair; Madsen, Larry C; West, Todd H; Faltesek, Anthony; Henderson, Gavin D; Henderson, Christopher L; Leighton, Terrance

    2011-09-01

    Native air sampling (NAS) is distinguished from dedicated air sampling (DAS) devices (eg, BioWatch) that are deployed to detect aerosol disseminations of biological threat agents. NAS uses filter samples from heating, ventilation, and air conditioning (HVAC) systems in commercial properties for environmental sampling after DAS detection of biological threat agent incidents. It represents an untapped, scientifically sound, efficient, widely distributed, and comparably inexpensive resource for postevent environmental sampling. Calculations predict that postevent NAS would be more efficient than environmental surface sampling by orders of magnitude. HVAC filter samples could be collected from pre-identified surrounding NAS facilities to corroborate the DAS alarm and delineate the path taken by the bioaerosol plume. The New York City (NYC) Native Air Sampling Pilot Project explored whether native air sampling would be acceptable to private sector stakeholders and could be implemented successfully in NYC. Building trade associations facilitated outreach to and discussions with property owners and managers, who expedited contact with building managers of candidate NAS properties that they managed or owned. Nominal NAS building requirements were determined; procedures to identify and evaluate candidate NAS facilities were developed; data collection tools and other resources were designed and used to expedite candidate NAS building selection and evaluation in Manhattan; and exemplar environmental sampling playbooks for emergency responders were completed. In this sample, modern buildings with single or few corporate tenants were the best NAS candidate facilities. The Pilot Project successfully demonstrated that in one urban setting a native air sampling strategy could be implemented with effective public-private collaboration. PMID:21793731

  13. Council of U.S. Academy of Sciences Expresses Concern to Soviet Counterparts over Sakharov Harrassment.

    PubMed

    1973-09-21

    National Academy of Sciences (NAS) president Philip Handler has made public a cable to his opposite number in the Soviet Union expressing the "deep concern" of the NAS Council for the welfare of dissenting Soviet physicist Andrei Sakharov and warning that, if further measures were taken against Sakharov, "it would be extremely difficult to imagine successful fulfillment of American pledges of binational scientific cooperation . . . ." Handler's message is the strongest public expression to date of NAS concern over treatment of Soviet scientists and other intellectuals (Science, 6 April). The cable, addressed to M. V. Keldysh, president of the Soviet Academy of Sciences, is given in full below. PMID:17744285

  14. Alternative Architectures for Distributed Work in the National Airspace System

    NASA Technical Reports Server (NTRS)

    Smith, Philip J.; Billings, Charles E.; Chapman, Roger; Obradovich, Heintz; McCoy, C. Elaine; Orasanu, Judith

    2000-01-01

    The architecture for the National Airspace System (NAS) in the United States has evolved over time to rely heavily on the distribution of tasks and control authority in order to keep cognitive complexity manageable for any one individual. This paper characterizes a number of different subsystems that have been recently incorporated in the NAS. The goal of this discussion is to begin to identify the critical parameters defining the differences among alternative architectures in terms of the locus of control and in terms of access to relevant data and knowledge. At an abstract level, this analysis can be described as an effort to describe alternative "rules of the game" for the NAS.

  15. Errores fotométricos debido al uso del filtro anular de mediana en imágenes CCD

    NASA Astrophysics Data System (ADS)

    Gil-Hutton, R.; Cañada, M.; Noel, N.

    El filtro anular de mediana tiene la importante propiedad de tener una escala claramente definida, lo que permite remover de una imagen CCD todos los objetos con tamaños menores a esta escala, independientemente de su morfología particular, y reemplazarlos por el correspondiente ``background" local. Este filtro es de gran utilidad para remover gradientes de fondo, ``fringing" y halos de objetos extendidos mediante el simple procedimiento de restar a la imagen original una imagen filtrada, repitiendo el proceso las veces que sea necesario. En este trabajo se presentan resultados sobre los errores que introduce este filtro en la fotometría de objetos con diferente relación S/N y su aplicación a imágenes con gradientes de fondo y ``fringing".

  16. Órbitas caóticas en satelites galácticos

    NASA Astrophysics Data System (ADS)

    Carpintero, D. D.; Muzzio, J. C.; Vergne, M. M.; Wachlin, F. C.

    En trabajos anteriores investigamos las órbitas de estrellas que forman los satelites galácticos utilizando análisis de frecuencias. Su uso estaba plenamente justificado por su velocidad y la gran información que brinda, amén de haber dado resultados muy concordantes con los exponentes de Liapunov. Sin embargo, más recientemente, encontramos algunos problemas en la utilización del análisis de frecuencias en sistemas de referencia rotantes (como se utilizan para los satélites), por lo que en este trabajo rehicimos nuestras investigaciones previas utilizando exclusivamente exponentes de Liapunov. Algunas conclusiones anteriores se han confirmado, en tanto que otras deben modificarse. Además, los nuevos resultados muestran que las escalas de tiempo de los procesos caóticos en los satélites galácticos son comparables a, o más cortas que, las escalas de tiempo de otros procesos dinámicos característicos de estos objetos.

  17. Fotometría de imágenes CCD insuficientemente muestreadas

    NASA Astrophysics Data System (ADS)

    Ostrov, P. G.

    Se enfrenta el problema de la fotometría de imágenes CCD con una escala inadecuada (fwhm menor o igual que el tamaño de un pixel) y psf fuertemente variable con la posición. Se analiza, en particular, la aplicabilidad de una táctica propuesta por Massey, consistente en eliminar las vecinas débiles (utilizando una psf rudimentaria) para luego efectuar una fotometría de apertura sobre las estrellas brillantes. Se determina, mediante experimentos numéricos, la precisión alcanzada mediante esta técnica.

  18. Non-caloric artificial sweeteners and the microbiome: findings and challenges.

    PubMed

    Suez, Jotham; Korem, Tal; Zilberman-Schapira, Gili; Segal, Eran; Elinav, Eran

    2015-01-01

    Non-caloric artificial sweeteners (NAS) are common food supplements consumed by millions worldwide as means of combating weight gain and diabetes, by retaining sweet taste without increasing caloric intake. While they are considered safe, there is increasing controversy regarding their potential ability to promote metabolic derangements in some humans. We recently demonstrated that NAS consumption could induce glucose intolerance in mice and distinct human subsets, by functionally altering the gut microbiome. In this commentary, we discuss these findings in the context of previous and recent works demonstrating the effects of NAS on host health and the microbiome, and the challenges and open questions that need to be addressed in understanding the effects of NAS consumption on human health. PMID:25831243

  19. Space-X Launches Falcon 9 on Demonstration Flight - Duration: 2 minutes, 20 seconds.

    NASA Video Gallery

    SpaceX's Falcon 9 rocket and Dragon spacecraft launched from Launch Complex 40 at Cape Canaveral Air Force Station at 10:43 a.m. EST on Wednesday, Dec. 8. This is first demonstration flight for NAS...

  20. ADVISORY ON UPDATED METHODOLOGY FOR ESTIMATING CANCER RISKS FROM EXPOSURE TO IONIZING RADIATION

    EPA Science Inventory

    The National Academy of Sciences (NAS) published the Biological Effects of Ionizing Radiation (BEIR) committee's report (BEIR VII) on risks from ionizing radiation exposures in 2006. The Committee analyzed the most recent epidemiology from the important exposed cohorts and factor...

  1. Characterizing adult human nasal airway dimensions

    SciTech Connect

    Guilmette, R.A.; Griffith, W.C.

    1994-11-01

    Respiratory tract models used in calculating radiation dose from exposure to inhaled radioactive aerosols have only recently focused attention on the importance of the nasal airways (NAs). Because the NAs are the first tissues of the respiratory tract available for aerosol deposition in normally nose-breathing people, any deposition of aerosol in this anatomical structure will reduce the amounts available to be deposited in the remainder of the respiratory tract. Thus, uncertainties in estimating the deposition fractions in the NAs will propagate throughout the remainder of the respiratory tract, creating errors in the calculated dose estimates. Additionally, there is evidence that the NAs are also at risk for induction of cancer from exposure to certain occupational aerosols such as wood dust, leather dust, chromium, and nickel. The purpose of this investigation was to conduct an anatomical study to assess the variabilities in NA dimensions.

  2. Health Risk of Radon

    MedlinePLUS

    ... related lung cancer in women. Top of Page Biological Effects of Ionizing Radiation (BEIR) VI Report: "The ... of Sciences' (NAS) latest report on radon, the Biological Effects of Ionizing Radiation (BEIR) VI Report (1999). ...

  3. 21 CFR 522.44 - Sterile sodium acetazolamide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .... (c) Conditions of use. (1) It is used as an aid in the treatment of dogs with mild congestive heart failure and for rapid reduction of intraocular pressure.1 1 These conditions are NAS/NRC reviewed...

  4. 21 CFR 522.44 - Sterile sodium acetazolamide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .... (c) Conditions of use. (1) It is used as an aid in the treatment of dogs with mild congestive heart failure and for rapid reduction of intraocular pressure.1 1 These conditions are NAS/NRC reviewed...

  5. Sodium-sulfur battery flight experiment definition study

    NASA Technical Reports Server (NTRS)

    Chang, Rebecca; Minck, Robert

    1990-01-01

    Sodium-sulfur batteries are considered to be one of the most likely battery systems for space applications. Compared with the Ni-H2 or Ni-Co battery systems, Na-S batteries offer a mass reduction by a factor of 2 to 4, representing significant launch cost savings or increased payload mass capabilities. The Na-S battery operates at between 300 and 400 C, using liquid sodium and sulfur/polysulfide electrodes and solid ceramic electrolyte; the transport of the electrode materials to the surface of the electrolyte is through wicking/capillary forces. This paper describes five tests identified for the Na-S battery flight experiment definition study, which include the cell characterization test, the reactant distribution test, the current/temperature distribution test, the freeze/thaw test, and the multicell LEO test. A schematic diagram of Na-S cell is included.

  6. 78 FR 57130 - Proposed Information Collection; Comment Request; Conflict of Interest Disclosure for Nonfederal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-17

    ... National Oceanic and Atmospheric Administration Proposed Information Collection; Comment Request; Conflict... Sciences (NAS) policy for evaluating conflicts of interest when selecting peer reviewers who are not... review purposes, the term ``conflicts of interest'' means any financial or other ] interest...

  7. 77 FR 18791 - Proposed Information Collection; Comment Request; NIST Associates Information System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-28

    ... National Institute of Standards and Technology Proposed Information Collection; Comment Request; NIST Associates Information System AGENCY: National Institute of Standards and Technology (NIST). ACTION: Notice... Associates Information System (NAIS) information collection instrument(s) are completed by incoming NAs....

  8. JWST Secondary Mirror Deploy Timelapse - Duration: 86 seconds.

    NASA Video Gallery

    Setting up NASA's James Webb Space Telescope's secondary mirror in space will require special arms that resemble a tripod that was recently demonstrated in a NASA cleanroom. TRT: 1:25 / Credit: NAS...

  9. Construction of a convenient system for easily screening inhibitors of mutated influenza virus neuraminidases☆

    PubMed Central

    Shigemori, Tomohiro; Nagayama, Mitsuru; Yamada, Junki; Miura, Natsuko; Yongkiettrakul, Suganya; Kuroda, Kouichi; Katsuragi, Tohoru; Ueda, Mitsuyoshi

    2013-01-01

    Neuraminidase (NA) is a surface glycoprotein produced by the influenza virus. Specific NA mutations that confer resistance to anti-viral drugs have been reported. The aim of this study was to demonstrate quick preparation of the mutated NAs using the yeast surface display and its applicability for screening inhibitors. Plasmids encoding the head domain of wild-type and drug-resistant NAs were constructed and introduced into yeast, and these were successfully displayed on the yeast surface, with biochemical properties similar to the native virus NAs. This system using mutated NAs-displaying yeast provides an efficient and convenient tool for screening novel inhibitors against the drug-resistant influenza virus. PMID:24265981

  10. 77 FR 70155 - Notice of Intent To Prepare an Environmental Impact Statement for the Disposal and Reuse of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-23

    ... 1990, as amended in 2005 (BRAC Law). Potential impacts associated with reuse of NAS JRB Willow Grove..., including potential impacts on topography, geology and soils, water resources, biological resources,...

  11. 77 FR 64110 - Notice of Intent To Prepare an Environmental Impact Statement for the Disposal and Reuse of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-18

    ... 1990, as amended in 2005 (BRAC Law). Potential impacts associated with reuse of NAS JRB Willow Grove... human and natural environments, including potential impacts on topography, geology and soils,...

  12. Saturn and Enceladus Electrical Link - Duration: 12 seconds.

    NASA Video Gallery

    This animated graphic shows how Saturn and its moon Enceladus are electrically linked. Magnetic field lines, invisible to the human eye but detectable by the fields and particles instruments on NAS...

  13. A Celebration of the Space Shuttle Program - Duration: 105 seconds.

    NASA Video Gallery

    On September 23, 2011, NASA Langley hosted a Shuttle Celebration at the Virginia Air & Space Center in Hampton, Va. More than 650 guests attended, including STS-135 Commander Chris Ferguson and NAS...

  14. CONTRIBUTION OF SEMI-VOLATILE PARTICULATE MATTER TO AMBIENT SUSPENDED FINE PARTICLE MASS

    EPA Science Inventory

    Scope: The periodic (5 years) review of the National Ambient Air Quality Standard (NAAQS) for particulate matter (PM) and the subsequent determination by EPA and NAS of particulate matter research needs have identified areas of uncertainty including exposure measurement th...

  15. Development of remedial process options: Phase II, Feasibility study: Installation Restoration Program, Naval Air Station Fallon, Fallon, Nevada

    SciTech Connect

    Cronk, T.A.; Smuin, D.R. ); Schlosser, R.M. )

    1991-11-01

    This technical memorandum develops process options which are appropriate for environmental restoration activities at Naval Air Station Fallon (NAS Fallon), Nevada. Introduction of contaminants to the environment has resulted from deliberate disposal activities (both through dumping and landfilling) and accidental spills and leaks associated with normal activities at NAS Fallon over its lifetime of operation. Environmental sampling results indicate that the vast majority of contaminants of concern are petroleum hydrocarbon related. These contaminants include JP-4, JP-5, leaded and unleaded gasoline, waste oils and lubricants, hydraulic fluids, and numerous solvents and cleaners. The principal exposure pathways of concern associated with NAS Fallon contaminants appear to be the surface flows and shallow drainage systems to which the base contributes. Available data indicate NAS Fallon IR Program sites are not contributing excessive contamination to surface flows emanating from the base. Contaminants appear to be contained in a relatively immobile state in the shallow subsurface with little or no contaminant migration off site.

  16. GUIDELINES FOR CARCINOGEN RISK ASSESSMENT (1986)

    EPA Science Inventory

    In 1983, the National Academy of Sciences (NAS)/National Research Council (NRC) published its report entitled Risk Assessment in the Federal Government: Managing the Process. In that report, the NRC recommended that Federal regulatory agencies establish "inference guidelines" to ...

  17. ONTOGENY OF PROTEINS FOR USE AS BIOMARKERS OF DEVELOPMENTAL NEUROTOXICITY.

    EPA Science Inventory

    The developing nervous system can be uniquely susceptible to adverse effects following exposure to environmental chemicals, and several advisory panels (e.g. ILSI, NRC, NAS) have highlighted the need for rapid and sensitive developmental neurotoxicity testing methods. Measurement...

  18. Application of the Web-based Interspecies Correlation Estimation (Web-ICE) tool to assess risks of national pesticide registrations to federally listed (threatened and endangered) species

    EPA Science Inventory

    The National Academy of Science (NAS) recently recommended exploration of predictive tools, such as interspecies correlation estimation (ICE), to estimate acute toxicity values for listed species and support development of species sensitivity distributions (SSDs). We explored the...

  19. Neonatal abstinence syndrome: Pharmacologic strategies for the mother and infant.

    PubMed

    Kraft, Walter K; Stover, Megan W; Davis, Jonathan M

    2016-04-01

    Opioid use in pregnancy has increased dramatically over the past decade. Since prenatal opioid use is associated with numerous obstetrical and neonatal complications, this now has become a major public health problem. In particular, in utero opioid exposure can result in neonatal abstinence syndrome (NAS) which is a serious condition characterized by central nervous system hyperirritability and autonomic nervous system dysfunction. The present review seeks to define current practices regarding the approach to the pregnant mother and neonate with prenatal opiate exposure. Although the cornerstone of prenatal management of opioid dependence is opioid maintenance therapy, the ideal agent has yet to be definitively established. Pharmacologic management of NAS is also highly variable and may include an opioid, barbiturate, and/or α-agonist. Genetic factors appear to be associated with the incidence and severity of NAS. Establishing pharmacogenetic risk factors for the development of NAS has the potential for creating opportunities for "personalized genomic medicine" and novel, individualized therapeutic interventions. PMID:26791055

  20. IRIS Toxicological Review of Formaldehyde (Inhalation) (External Review Draft 2010)

    EPA Science Inventory

    UPDATE EPA is currently revising its Integrated Risk Information System (IRIS) assessment of formaldehyde to address the 2011 NAS peer review recommendations. This assessment addresses both noncancer and cancer human health effects that are relevant to assessing ...

  1. Evaluating the Suitability of CPTEC Reanalysis Data Over the LBA Study Area as Atmospheric Forcing for use in SALDAS and Regional Parameter Optimization Studies

    NASA Astrophysics Data System (ADS)

    de Goncalves, L. G.; Shuttleworth, W. J.; Herdies, D. L.; Bastidas, L. A.; Kato, H.; Rosolem, R.; Rosero, E.; Aravéquia, J. A.; Toll, D. L.; Rodell, M.

    2006-12-01

    The availability of reliable atmospheric forcing data is a critical component of the South American Land Data Assimilation System (SALDAS) because it is the primary driver for the participating Land Surface Models (LSM) in the system. Because SALDAS, is built on the framework of the NASA/LIS (Land Information System) and is therefore distributed, the recently released CPTEC/INPE (Centro de Previsão do Tempo e Estudos Climáticos/Instituto Nacional de Pesquisas Espaciais) South American Regional Reanalysis (SARR) has been selected as the primary atmospheric forcing dataset for use with the SALDAS. The SARR integrates upper air and surface observations from several sources over South America, including vertical soundings from RACCI-LBA and SALLJEX-PROSUR field campaigns over the Amazon and the low level jet regions along the Andes respectively. The SARR is based on the Eta model Regional Physical-space Statistical System (RPSAS) data assimilation scheme applied at 40Km horizontal resolution and 38 vertical levels, and currently spans the time period 2000-2004. In this study, the SARR is validated against surface observations across the the LBA study area, including flux tower measurements, with two main objectives: (a) to evaluate how well the SARR atmospheric forcing compares with observed point and area-averaged values, in order to investigate the feasibility of transferring LSM parameters derived at LBA towers sites to surrounding areas; and (b) to evaluate how SALDAS Runs made with SARR forcing over the LBA region compare with the expected hydroclimatology of the Amazon as a regional entity. This study is being carried out jointly by the CD-36 group in the LBA-Eco Synthesis Phase and by the SALDAS initiative, which is part of the GLDAS project at the GSFC/NASA Hydrological Sciences Branch.

  2. Biomass Burning Emissions in the Cerrado of Brazil Computed with Remote Sensing Data and GIS

    NASA Technical Reports Server (NTRS)

    Guild, Liane S.; Brass, James A.; Chatfield, Robert B.; Hlavka, Christine A.; Riggan, Philip J.; Setzer, Alberto; Pereira, Joao A. Raposo; Peterson, David L. (Technical Monitor)

    1994-01-01

    Biomass burnin is a common force in much of the developing tropical world where it has wide-ranging environmental impacts. Fire is a component of tropical deforestation and is 0 p often used to clear broad expanses of land for shifting agriculture and cattle ranching. Frequent burning in the tropical savannas is a distinct problem from that of primary forest. In Brazil, most of the burning occurs in the cerrado which occupies approximately 1,800,000 km2, primarily on the great plateau in central Brazil. Wildland and agricultural fires are dramatic sources of regional air pollution in central Brazil. Biomass burning is an important source of a large number of trace gases including greenhouse gases and other chemically active species. Knowledge of trace gas emissions from biomass burning in Brazil is limited by a number of factors, most notably relative emission factors for gases from specific fire types/fuels and accurate estimates of temporal and spatial distribution and extent of fire activity. Estimates of trace gas emissions during September 1992 will be presented that incorporates a digital map of vegetation classes, pyrogenic emission factors calculated from ground and aircraft missions, and Instituto Nacional de Pesquisas Espaciais (INPE) fire products derived from Advanced Very High Resolution Radiometer (AVHRR) data. The regional emissions calculated from National Oceanographic and Atmospheric Administration (NOAA) AVHRR estimates of fire activity will provide an independent estimate for comparison with results obtained by the National Aeronautics and Space Administration (NASA) Transport and Atmospheric Chemistry Near the Equator - Atlantic (TRACE-A) experiments.

  3. New Directions in Land Remote Sensing Policy and International Cooperation

    NASA Astrophysics Data System (ADS)

    Stryker, Timothy

    2010-12-01

    Recent changes to land remote sensing satellite data policies in Brazil and the United States have led to the phenomenal growth in the delivery of land imagery to users worldwide. These new policies, which provide free and unrestricted access to land remote sensing data over a standard electronic interface, are expected to provide significant benefits to scientific and operational users, and open up new areas of Earth system science research and environmental monitoring. Freely-available data sets from the China-Brazil Earth Resources Satellites (CBERS), the U.S. Landsat satellites, and other satellite missions provide essential information for land surface monitoring, ecosystems management, disaster mitigation, and climate change research. These missions are making important contributions to the goals and objectives of regional and global terrestrial research and monitoring programs. These programs are in turn providing significant support to the goals and objectives of the United Nations Framework Convention on Climate Change (UN FCCC), the Global Earth Observation System of Systems (GEOSS), and the UN Reduction in Emissions from Deforestation and Degradation (REDD) program. These data policies are well-aligned with the "Data Democracy" initiative undertaken by the international Committee on Earth Observation Satellites (CEOS), through its current Chair, Brazil's National Institute for Space Research (Instituto Nacional de Pesquisas Espaciais, or INPE), and its former chairs, South Africa's Council for Scientific and Industrial Research (CSIR) and Thailand's Geo Informatics and Space Technology Development Agency (GISTDA). Comparable policies for land imaging data are under consideration within Europe and Canada. Collectively, these initiatives have the potential to accelerate and improve international mission collaboration, and greatly enhance the access, use, and application of land surface imagery for environmental monitoring and societal adaption to changing climate conditions.

  4. LISA 8 Science Organizing Committee and Local Organizing Committee LISA 8 Science Organizing Committee and Local Organizing Committee

    NASA Astrophysics Data System (ADS)

    2011-05-01

    Science Organising Committee (SOC) Tom Abel, Stanford University Odylio Aguiar, Instituto Nacional de Pesquisas Espaciais Tal Alexander, Wizemann Institute Peter Bender, University of Colorado Pierre Binetruy, APC - College de France Sasha Buchman, Stanford University Robert Byer, Stanford University Manuela Campanelli, University of Texas Joan Centrella, NASA/Goddard Massimo Cerdonio, University of Padova Eugenio Coccia, University of Roma-2 Neil Cornish, Montana State University Michael Cruise, University of Birmingham Curt Cutler, NASA/JPL Karsten Danzmann, University of Hannover Sam Finn, Penn State University Jens Gundlach, NPL Gerhard Heinzel, Max-Planck-Institut fuer Gravitationsphysik Craig Hogan, University of Washington Jim Hough, University of Glasgow Scott Hughes, MIT Oliver Jennrich, ESTEC Philippe Jetzer, University Zurich Seiji Kawamura, National Observatory, Japan Alberto Lobo, ICE-CSIC and IEEC Avi Loeb, Harvard University Piero Madau, Lick Observatory Yannick Mellier, IAP, Paris Peter Michelson, Stanford University Guido Mueller, University of Florida Sterl Phinney, Caltech Tom Prince, NASA/JPL Doug Richstone, University of Michigan Bernard Schutz, AEI Potsdam Tuck Stebbins, NASA/Goddard Tim Sumner, Imperial College, London Ke-Xun Sun, Stanford University Kip Thorne, Caltech Michele Vallisneri, NASA/JPL Alberto Vecchio, University of Birmingham Jean-Yves Vinet, OCA, Nice Stefano Vitale, University of Trento Rai Weiss, MIT Nick White, NASA/Goddard Local Organising Committee (LOC) Sasha Buchman (Stanford University) Robert Byer (Stanford University) Sara Charbonneau-Lefort (Stanford University) Nancy Christianson (Stanford University) John Conklin (Stanford University) Dan DeBra (Stanford University) Jan Goebel (Stanford University) Vivian Drew (Stanford University) Ke-Xun Sun (Stanford University) Lucy Zhou (Stanford University) Andrea Zoellner (Stanford University)

  5. Jpcam: a 1.2 Gpixel Camera for the J-Pas Survey

    NASA Astrophysics Data System (ADS)

    Taylor, K.; Marín-Franch, A.; Laporte, R.; Santoro, F. G.; Marrara, L.; Cepa, J.; Cenarro, A. J.; Chueca, S.; Cristobal-Hornillos, D.; Ederoclite, A.; Gruel, N.; Moles, M.; Rueda, F.; Rueda, S.; Varela, J.; Yanes, A.; Benitez, N.; Dupke, R.; Fernández-Soto, A.; Jorden, P.; Lousberg, G.; Molino Benito, A.; Palmer, I.; Mendes de Oliveira, C.; Sodré, L.

    JPCam is a 14-CCD mosaic camera, using the new e2v 9k-by-9k 10 ?m-pixel 16-channel detectors, to be deployed on a dedicated 2.55 m wide-field telescope at the OAJ (Observatorio Astrofísico de Javalambre) in Aragon, Spain. The camera is designed to perform a Baryon Acoustic Oscillations (BAO) survey of the northern sky. The J-PAS survey strategy will use 54 relatively narrow-band ( 13.8 nm) filters equi-spaced between 370 and 920 nm plus 3 broad-band filters to achieve unprecedented photometric red-shift accuracies for faint galaxies over 8000 square degrees of sky. The cryostat, detector mosaic and read electronics, is being supplied by e2v under contract to J-PAS while the mechanical structure, housing the shutter and filter assembly, is being designed and constructed by a Brazilian consortium led by INPE (Instituto Nacional de Pesquisas Espaciais). The cryostat is bridged to the telescope via a hexapod actuator system to maintain image quality across the field. Four sets of 14 filters are placed in the ambient environment, just above the dewar window but directly in line with the detectors, leading to a mosaic having 10 mm gaps between each CCD. The massive 500 mm aperture shutter is expected to be supplied by the Bonn-Shutter UG. We will present an overview of JPCam, from the filter configuration through to the CCD mosaic camera. A brief outline of the main J-PAS science projects will be included.

  6. CTAS and NASA Air Traffic Management Fact Sheets for En Route Descent Advisor and Surface Management System

    NASA Technical Reports Server (NTRS)

    Lee, Katharine

    2004-01-01

    The Surface Management System (SMS) is a decision support tool that will help controllers, traffic managers, and NAS users manage the movements of aircraft on the surface of busy airports, improving capacity, efficiency, and flexibility. The Advanced Air Transportation Technologies (AATT) Project at NASA is developing SMS in cooperation with the FAA's Free Flight Phase 2 (FFP2) pro5ram. SMS consists of three parts: a traffic management tool, a controller tool, and a National Airspace System (NAS) information tool.

  7. Comparison of sporadic sodium layer characteristics observed at different time resolutions

    NASA Astrophysics Data System (ADS)

    Liu, Y. J.; Clemesha, B. R.; Wang, J. H.; Cheng, X. W.

    2013-11-01

    Sporadic sodium (Nas) layers, occurring in roughly the same height range as ionospheric sporadic-E layers, were first detected by lidar some 30 yr ago. Nas layers have a typical thickness of a few hundred meters to a few km, with peak atom concentrations several times that of the background layer. Despite a great deal of excellent work over the past decades, the source of Nas layers is still not altogether clear, partly as a result of our incomplete knowledge of Nas layer characteristics. In this paper we concentrate on some typical case studies chosen from the ~127 h of sporadic sodium layer observations made at a time resolution of 1.5 s at Yanqing (115.97° E, 40.47° N), Beijing, China. This is a much better time resolution than what has been employed in most earlier measurements. The results show that the Nas layer peak heights are dispersed at slightly different although adjacent heights. When averaged over several minutes, as has been the case with most earlier measurements, the height scatter results in an apparent layer thickness of a few km. We conclude, therefore, that these dispersed peaks at different but adjacent heights constitute the 5 min Nas layer. Similar to the observations of sporadic-E-ion (Es) layers and meteor rate, we observe quasi-periodic fluctuations on a timescale on the order of several minutes in the peak height and the peak density of sporadic layers, which is a universal feature but concealed by the lower temporal resolution previously adopted. Spatially localized multiple scatterers and multiple thin layers with similar apparent movement in Nas layers are also found. We discuss the possible formation mechanism by the direct deposition of large swarms of micrometeoroids and demonstrate a typical example of meteor trails evolving into a Nas layer, which suggests that this mechanism might indeed occur.

  8. Ambient temperature sodium-sulfur batteries.

    PubMed

    Manthiram, Arumugam; Yu, Xingwen

    2015-05-13

    Ambient- or room-temperature sodium-sulfur batteries (RT Na-S) are gaining much attention as a low-cost option for large-scale electrical energy storage applications. However, their adoption is hampered by severe challenges. This concept paper summarizes first the operating principles, history, recent progress, and challenges of RT Na-S battery technology, and then suggests future directions towards enhancing performance in order for it to be a viable technology. PMID:25565554

  9. Traction microscopy to identify force modulation in sub-resolution adhesions

    PubMed Central

    Han, Sangyoon J.; Oak, Youbean; Groisman, Alex; Danuser, Gaudenz

    2015-01-01

    We present a reconstruction algorithm that resolves cellular tractions in diffraction-limited nascent adhesions (NAs). The enabling method is the introduction of sparsity regularization to the solution of the inverse problem, which suppresses noise without underestimating traction magnitude. We show that NAs transmit a distinguishable amount of traction and that NA maturation depends on traction growth rate. A software package implementing this numerical approach is provided. PMID:26030446

  10. Infant and maternal characteristics in neonatal abstinence syndrome--selected hospitals in Florida, 2010-2011.

    PubMed

    Lind, Jennifer N; Petersen, Emily E; Lederer, Philip A; Phillips-Bell, Ghasi S; Perrine, Cria G; Li, Ruowei; Hudak, Mark; Correia, Jane A; Creanga, Andreea A; Sappenfield, William M; Curran, John; Blackmore, Carina; Watkins, Sharon M; Anjohrin, Suzanne

    2015-03-01

    Neonatal abstinence syndrome (NAS) is a constellation of physiologic and neurobehavioral signs exhibited by newborns exposed to addictive prescription or illicit drugs taken by a mother during pregnancy. The number of hospital discharges of newborns diagnosed with NAS has increased more than 10-fold (from 0.4 to 4.4 discharges per 1,000 live births) in Florida since 1995, far exceeding the three-fold increase observed nationally. In February 2014, the Florida Department of Health requested the assistance of CDC to 1) assess the accuracy and validity of using Florida's hospital inpatient discharge data, linked to birth and infant death certificates, as a means of NAS surveillance and 2) describe the characteristics of infants with NAS and their mothers. This report focuses only on objective two, describing maternal and infant characteristics in the 242 confirmed NAS cases identified in three Florida hospitals during a 2-year period (2010-2011). Infants with NAS experienced serious medical complications, with 97.1% being admitted to an intensive care unit, and had prolonged hospital stays, with a mean duration of 26.1 days. The findings of this investigation underscore the important public health problem of NAS and add to current knowledge on the characteristics of these mothers and infants. Effective June 2014, NAS is now a mandatory reportable condition in Florida. Interventions are also needed to 1) increase the number and use of community resources available to drug-abusing and drug-dependent women of reproductive age, 2) improve drug addiction counseling and rehabilitation referral and documentation policies, and 3) link women to these resources before or earlier in pregnancy. PMID:25742381

  11. A survey of parallel programming tools

    NASA Technical Reports Server (NTRS)

    Cheng, Doreen Y.

    1991-01-01

    This survey examines 39 parallel programming tools. Focus is placed on those tool capabilites needed for parallel scientific programming rather than for general computer science. The tools are classified with current and future needs of Numerical Aerodynamic Simulator (NAS) in mind: existing and anticipated NAS supercomputers and workstations; operating systems; programming languages; and applications. They are divided into four categories: suggested acquisitions, tools already brought in; tools worth tracking; and tools eliminated from further consideration at this time.

  12. Investigation of Advanced Counterrotation Blade Configuration Concepts for High Speed Turboprop Systems. Task 8: Cooling Flow/heat Transfer Analysis User's Manual

    NASA Technical Reports Server (NTRS)

    Hall, Edward J.; Topp, David A.; Heidegger, Nathan J.; Delaney, Robert A.

    1994-01-01

    The focus of this task was to validate the ADPAC code for heat transfer calculations. To accomplish this goal, the ADPAC code was modified to allow for a Cartesian coordinate system capability and to add boundary conditions to handle spanwise periodicity and transpiration boundaries. This user's manual describes how to use the ADPAC code as developed in Task 5, NAS3-25270, including the modifications made to date in Tasks 7 and 8, NAS3-25270.

  13. USGS Nonindigenous Aquatic Species database with a focus on the introduced fishes of the lower Tennessee and Cumberland drainages

    USGS Publications Warehouse

    Fuller, Pam L.; Cannister, Matthew

    2013-01-01

    The Nonindigenous Aquatic Species (NAS) database (http://nas.er.usgs.gov) functions as a national repository and clearinghouse for occurrence data for introduced species within the United States. Included is locality information on over 1,100 species of vertebrates, invertebrates, and vascular plants introduced as early as 1850. Taxa include foreign (exotic) species and species native to North America that have been transported outside of their natural range. Locality data are obtained from published and unpublished literature, state, federal and local monitoring programs, museum accessions, on-line databases, websites, professional communications and on-line reporting forms. The NAS web site provides immediate access to new occurrence records through a real-time interface with the NAS database. Visitors to the web site are presented with a set of pre-defined queries that generate lists of species according to state or hydrologic basin of interest. Fact sheets, distribution maps, and information on new occurrences are updated as new records and information become available. The NAS database allows resource managers to learn of new introductions reported in their region or nearby regions, improving response time. Conversely, managers are encouraged to report their observations of new occurrences to the NAS database so information can be disseminated to other managers, researchers, and the public. In May 2004, the NAS database incorporated an Alert System to notify registered users of new introductions as part of a national early detection/rapid response system. Users can register to receive alerts based on geographic or taxonomic criteria. The NAS database was used to identify 23 fish species introduced into the lower Tennessee and Cumberland drainages. Most of these are sport fish stocked to support fisheries, but the list also includes accidental and illegal introductions such as Asian Carps, clupeids, various species popular in the aquarium trade, and Atlantic Needlefish (Strongylura marina) that was introduced via the newly-constructed Tennessee-Tombigbee Canal.

  14. Postexposure Prophylactic Effect of Hepatitis B Virus (HBV)-Active Antiretroviral Therapy against HBV Infection

    PubMed Central

    Watanabe, Tsunamasa; Hamada-Tsutsumi, Susumu; Yokomaku, Yoshiyuki; Imamura, Junji; Sugiura, Wataru

    2014-01-01

    Retrospective study indicates that hepatitis B virus (HBV)-active nucleoside (nucleotide) analogues (NAs) used for antiretroviral therapy reduce the incidence of acute HBV infections in human immunodeficiency virus (HIV)-infected patients. Learning from HIV postexposure prophylaxis (PEP), we explored the possibility of using NAs in PEP following HBV exposure, if preexposure prophylaxis is feasible clinically. Using freshly isolated primary human hepatocytes cultured in vitro, we analyzed the effect of HBV-active tenofovir and lamivudine in primary HBV infection and also the effect of treatment with these NAs after HBV infection. HBV-active NAs applied from 24 h before inoculation could not prevent the secretion of hepatitis B surface antigen into the culture medium, and cessation of the NAs after inoculation allowed the cells to establish an apparent HBV infection. In contrast, hepatitis B immune globulin was able to prevent HBV infection completely. NA treatment before infection, however, can control the spread of HBV infection, as detected by immunohistochemistry. Practically, starting NA treatment within 2 days of primary HBV infection inhibited viral spread effectively, as well as preexposure treatment. We demonstrated that preexposure NA treatment was not able to prevent the acquisition of HBV infection but prevented viral spread by suppressing the production of mature progeny HBV virions. The effect of postexposure treatment within 2 days was similar to the effect of preexposure treatment, suggesting the possibility of HBV PEP using HBV-active NAs in HIV- and HBV-susceptible high-risk groups. PMID:25512419

  15. Staying the Course: Facility and Profession Retention among Nursing Assistants in Nursing Homes

    PubMed Central

    Stearns, Sally C.; D'Arcy, Laura P.

    2015-01-01

    Objectives High turnover rates among nursing assistants (NAs) in nursing homes have costly implications for facility operation and quality, while low rates of NA profession retention can deplete the stock of experienced staff. This study assesses the extent to which the same factors are associated with NAs' intent to leave a particular job versus the NA profession. Methods We used data for 2,328 NAs from the 2004 National Nursing Assistant Survey to model: (a) two measures of facility retention (whether NAs expect to leave their current job within one year and whether they are also searching for a new job); and (b) NA profession retention, measured by whether NAs do not expect their next job to be as a nursing assistant. Results Substantially different factors affect facility versus profession retention. Facility characteristics (including supervisor qualities, training/safety and benefits) primarily affect facility retention while NA profession retention is negatively associated with income and education. Discussion Facilities can implement specific actions to retain NAs, though such policies may have limited effect on retention in the profession. Broader enhancements of career opportunities may be necessary for profession retention, though balance between retention and promotion may be important. PMID:18559686

  16. Normalizing motor cortex representations in focal hand dystonia.

    PubMed

    Schabrun, Siobhan M; Stinear, Cathy M; Byblow, Winston D; Ridding, Michael C

    2009-09-01

    Task-specific focal dystonia is thought to have a neurological basis where stereotypical synchronous inputs and maladaptive plasticity play a role. As afferent input is a powerful driver of cortical reorganization, we propose that a period of asynchronous afferent stimulation may reverse maladaptive cortical changes and alleviate symptoms. Using transcranial magnetic stimulation (TMS), 3 hand muscles were mapped in 10 dystonics and 10 healthy controls. Mapping occurred before and after 1 h of nonassociative stimulation (NAS) to first dorsal interosseous (FDI) and abductor pollicis brevis (APB). Participants performed grip lift, handwriting, and cyclic drawing before and after NAS. Prior to NAS, dystonics had larger maps, and the centers of gravity (CoGs) of the FDI and APB maps were closer together. Dystonics demonstrated impairments in grip-lift, handwriting, and cyclic drawing tasks. Following NAS, map size was reduced in all muscles in dystonic participants and FDI and APB CoGs moved further apart. Among dystonics, NAS produced a reduction in movement variability during cyclic drawing. Thus, 1 h of NAS can reduce the magnitude, and increase the separation, of TMS representational maps. We suggest that these changes reflect some normalization of the representational abnormalities seen in focal dystonia and provide initial, limited evidence that such changes are associated with improvements in circle drawing. PMID:19074753

  17. Making Each Other’s Daily Life: Nurse Assistants’ Experiences and Knowledge on Developing a Meaningful Daily Life in Nursing Homes

    PubMed Central

    James, Inger; Fredriksson, Carin; Wahlström, Catrin; Kihlgren, Annica; Blomberg, Karin

    2014-01-01

    Background: In a larger action research project, guidelines were generated for how a meaningful daily life could be developed for older persons. In this study, we focused on the nurse assistants’ (NAs) perspectives, as their knowledge is essential for a well-functioning team and quality of care. The aim was to learn from NAs’ experiences and knowledge about how to develop a meaningful daily life for older persons in nursing homes and the meaning NAs ascribe to their work. Methods: The project is based on Participatory and Appreciative Action and Reflection. Data were generated through interviews, participating observations and informal conversations with 27 NAs working in nursing homes in Sweden, and a thematic analysis was used. Result: NAs developed a meaningful daily life by sensing and finding the “right” way of being (Theme 1). They sense and read the older person in order to judge how the person was feeling (Theme 2). They adapt to the older person (Theme 3) and share their daily life (Theme 4). NAs use emotional involvement to develop a meaningful daily life for the older person and meaning in their own work (Theme 5), ultimately making each other’s daily lives meaningful. Conclusion: It was obvious that NAs based the development of a meaningful daily life on different forms of knowledge: the oreticaland practical knowledge, and practical wisdom, all of which are intertwined. These results could be used within the team to constitute a meaningful daily life for older persons in nursing homes. PMID:25246997

  18. Culturing oil sands microbes as mixed species communities enhances ex situ model naphthenic acid degradation.

    PubMed

    Demeter, Marc A; Lemire, Joseph A; Yue, Gordon; Ceri, Howard; Turner, Raymond J

    2015-01-01

    Oil sands surface mining for bitumen results in the formation of oil sands process water (OSPW), containing acutely toxic naphthenic acids (NAs). Potential exists for OSPW toxicity to be mitigated by aerobic degradation of the NAs by microorganisms indigenous to the oil sands tailings ponds, the success of which is dependent on the methods used to exploit the metabolisms of the environmental microbial community. Having hypothesized that the xenobiotic tolerant biofilm mode-of-life may represent a feasible way to harness environmental microbes for ex situ treatment of OSPW NAs, we aerobically grew OSPW microbes as single and mixed species biofilm and planktonic cultures under various conditions for the purpose of assaying their ability to tolerate and degrade NAs. The NAs evaluated were a diverse mixture of eight commercially available model compounds. Confocal microscopy confirmed the ability of mixed and single species OSPW cultures to grow as biofilms in the presence of the NAs evaluated. qPCR enumeration demonstrated that the addition of supplemental nutrients at concentrations of 1 g L(-1) resulted in a more numerous population than 0.001 g L(-1) supplementation by approximately 1 order of magnitude. GC-FID analysis revealed that mixed species cultures (regardless of the mode of growth) are the most effective at degrading the NAs tested. All constituent NAs evaluated were degraded below detectable limits with the exception of 1-adamantane carboxylic acid (ACA); subsequent experimentation with ACA as the sole NA also failed to exhibit degradation of this compound. Single species cultures degraded select few NA compounds. The degradation trends highlighted many structure-persistence relationships among the eight NAs tested, demonstrating the effect of side chain configuration and alkyl branching on compound recalcitrance. Of all the isolates, the Rhodococcus spp. degraded the greatest number of NA compounds, although still less than the mixed species cultures. Overall, these observations lend support to the notion that harnessing a community of microorganisms as opposed to targeted isolates can enhance NA degradation ex situ. Moreover, the variable success caused by NA structure related persistence emphasized the difficulties associated with employing bioremediation to treat complex, undefined mixtures of toxicants such as OSPW NAs. PMID:26388865

  19. High Altitude Long Endurance Remotely Operated Aircraft - National Airspace System Integration - Simulation IPT: Detailed Airspace Operations Simulation Plan. Version 1.0

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The primary goal of Access 5 is to allow safe, reliable and routine operations of High Altitude-Long Endurance Remotely Operated Aircraft (HALE ROAs) within the National Airspace System (NAS). Step 1 of Access 5 addresses the policies, procedures, technologies and implementation issues of introducing such operations into the NAS above pressure altitude 40,000 ft (Flight Level 400 or FL400). Routine HALE ROA activity within the NAS represents a potentially significant change to the tasks and concerns of NAS users, service providers and other stakeholders. Due to the complexity of the NAS, and the importance of maintaining current high levels of safety in the NAS, any significant changes must be thoroughly evaluated prior to implementation. The Access 5 community has been tasked with performing this detailed evaluation of routine HALE-ROA activities in the NAS, and providing to key NAS stakeholders a set of recommended policies and procedures to achieve this goal. Extensive simulation, in concert with a directed flight demonstration program are intended to provide the required supporting evidence that these recommendations are based on sound methods and offer a clear roadmap to achieving safe, reliable and routine HALE ROA operations in the NAS. Through coordination with NAS service providers and policy makers, and with significant input from HALE-ROA manufacturers, operators and pilots, this document presents the detailed simulation plan for Step 1 of Access 5. A brief background of the Access 5 project will be presented with focus on Steps 1 and 2, concerning HALE-ROA operations above FL400 and FL180 respectively. An overview of project management structure follows with particular emphasis on the role of the Simulation IPT and its relationships to other project entities. This discussion will include a description of work packages assigned to the Simulation IPT, and present the specific goals to be achieved for each simulation work package, along with the associated deliverables necessary to achieve these goals and the needs of other Access 5 IPTs. The simulation environment chosen for this task is then outlined. This section includes a description of the system architecture, a list of the necessary assumptions made by the Simulation IPT, and the roles, responsibilities and interactions of simulation participants. The method of simulation conduct is presented in the next section with particular emphasis on scenario development and applicability to evaluation of Step 1 HALE-ROA operations. Following, data collection and analysis methods are discussed for air traffic specialists and air vehicle control station operators. Lastly, a schedule of Step 1 simulation activities is presented for reference.

  20. Culturing oil sands microbes as mixed species communities enhances ex situ model naphthenic acid degradation

    PubMed Central

    Demeter, Marc A.; Lemire, Joseph A.; Yue, Gordon; Ceri, Howard; Turner, Raymond J.

    2015-01-01

    Oil sands surface mining for bitumen results in the formation of oil sands process water (OSPW), containing acutely toxic naphthenic acids (NAs). Potential exists for OSPW toxicity to be mitigated by aerobic degradation of the NAs by microorganisms indigenous to the oil sands tailings ponds, the success of which is dependent on the methods used to exploit the metabolisms of the environmental microbial community. Having hypothesized that the xenobiotic tolerant biofilm mode-of-life may represent a feasible way to harness environmental microbes for ex situ treatment of OSPW NAs, we aerobically grew OSPW microbes as single and mixed species biofilm and planktonic cultures under various conditions for the purpose of assaying their ability to tolerate and degrade NAs. The NAs evaluated were a diverse mixture of eight commercially available model compounds. Confocal microscopy confirmed the ability of mixed and single species OSPW cultures to grow as biofilms in the presence of the NAs evaluated. qPCR enumeration demonstrated that the addition of supplemental nutrients at concentrations of 1 g L-1 resulted in a more numerous population than 0.001 g L-1 supplementation by approximately 1 order of magnitude. GC-FID analysis revealed that mixed species cultures (regardless of the mode of growth) are the most effective at degrading the NAs tested. All constituent NAs evaluated were degraded below detectable limits with the exception of 1-adamantane carboxylic acid (ACA); subsequent experimentation with ACA as the sole NA also failed to exhibit degradation of this compound. Single species cultures degraded select few NA compounds. The degradation trends highlighted many structure-persistence relationships among the eight NAs tested, demonstrating the effect of side chain configuration and alkyl branching on compound recalcitrance. Of all the isolates, the Rhodococcus spp. degraded the greatest number of NA compounds, although still less than the mixed species cultures. Overall, these observations lend support to the notion that harnessing a community of microorganisms as opposed to targeted isolates can enhance NA degradation ex situ. Moreover, the variable success caused by NA structure related persistence emphasized the difficulties associated with employing bioremediation to treat complex, undefined mixtures of toxicants such as OSPW NAs. PMID:26388865