Science.gov

Sample records for small structures research

  1. Radon entry into basements: Approach, experimental structures, and instrumentation of the small structures research project

    SciTech Connect

    Fisk, W.J.; Modera, M.P.; Sextro, R.G.; Garbesi, K.; Wollenberg, H.A.; Narasimhan, T.N.; Nuzum, T.; Tsang, Y.W.

    1992-02-01

    We describe the experimental approach, structures, and instrumentation of a research project on radon generation and transport in soil and entry into basements. The overall approach is to construct small precisely-fabricated basements in areas of different geology and climate, to control the pressures and ventilation rates in the structures, and to monitor radon concentrations and other relevant parameters over a period of one year or more. Two nearly air-tight structures have been constructed at the first site. The floor of each structure contains adjustable-width slots that serve as the only significant pathway for advective entry of radon. A layer of gravel underlays the floor of one structure; otherwise they are identical. The structures are instrumented for continuous or periodic monitoring of soil, structural, and meteorological parameters that affect radon entry. The pressure difference that drives advective radon entry can be maintained constant or varied over time. Soil gas and radon entry rates and associated parameters, such as soil gas pressures and radon concentrations, have been monitored for a range of steady-state and time-varying pressure differences between the interior of the structure and the soil. Examples of the experimentally-measured pressure and permeability fields in the soil around a structure are presented and discussed.

  2. Small Wastewater Systems Research

    EPA Pesticide Factsheets

    Small communities face barriers to building and maintaining effective wastewater treatment services, challenges include financial/economic limitations, lack of managerial training and geographic isolation/remoteness.

  3. Structures research

    NASA Technical Reports Server (NTRS)

    Abu-Saba, Elias; Mcginley, Williams; Shen, Ji-Yao

    1992-01-01

    The main objective of the structures group is to provide quality aerospace research with the Center for Aerospace Research - A NASA Center for Excellence at North Carolina Agricultural and Technical State University. The group includes dedicated faculty and students who have a proven record in the area of structures, in particular space structures. The participating faculty developed accurate mathematical models and effective computational algorithms to characterize the flexibility parameters of joint dominated beam-truss structures. Both experimental and theoretical modelling has been applied to the dynamic mode shapes and mode frequencies for a large truss system. During the past few months, the above procedures has been applied to the hypersonic transport plane model. The plane structure has been modeled as a lumped mass system by Doctor Abu-Saba while Doctor Shen applied the transfer matrix method with a piecewise continuous Timoshenko tapered beam model. Results from both procedures compare favorably with those obtained using the finite element method. These two methods are more compact and require less computer time than the finite element method. The group intends to perform experiments on structural systems including the hypersonic plane model to verify the results from the theoretical models.

  4. Small business innovation, research & development

    SciTech Connect

    Colvin, D.P.

    1995-12-31

    Historically, small businesses have been the innovation engine of the United States (US). The author provides statistical data that indicates that small business is really big business in the U.S. Small businesses are responsible for much of the applied research necessary for new product development. The author examines productivity, academic research and teaming as a cost-effective and time effective way to develop new products and technologies.

  5. 2002 SMALL SYSTEM RESEARCH

    EPA Science Inventory

    As research on smaller treatment devices grows, interest is also growing on how POU/POE can fit into a utility's overall strategy of providing safe and affordable water to customers in community and non-community transient and non-transient systems of all sizes. The EPA has been ...

  6. SMALL DRINKING WATER SYSTEMS RESEARCH

    EPA Science Inventory

    There are 159,796 Community Water Systems (CWSs) in the United States. Ninety-three percent of CWSs are considered very small to medium-sized systems that serve roughly 19% of the CWS population. In contrast, large to very large systems comprise just 7% of CWSs, but serve 81% of ...

  7. Small rocket research and technology

    NASA Technical Reports Server (NTRS)

    Schneider, Steven; Biaglow, James

    1993-01-01

    Small chemical rockets are used on nearly all space missions. The small rocket program provides propulsion technology for civil and government space systems. Small rocket concepts are developed for systems which encompass reaction control for launch and orbit transfer systems, as well as on-board propulsion for large space systems and earth orbit and planetary spacecraft. Major roles for on-board propulsion include apogee kick, delta-V, de-orbit, drag makeup, final insertions, north-south stationkeeping, orbit change/trim, perigee kick, and reboost. The program encompasses efforts on earth-storable, space storable, and cryogenic propellants. The earth-storable propellants include nitrogen tetroxide (NTO) as an oxidizer with monomethylhydrazine (MMH) or anhydrous hydrazine (AH) as fuels. The space storable propellants include liquid oxygen (LOX) as an oxidizer with hydrazine or hydrocarbons such as liquid methane, ethane, and ethanol as fuels. Cryogenic propellants are LOX or gaseous oxygen (GOX) as oxidizers and liquid or gaseous hydrogen as fuels. Improved performance and lifetime for small chemical rockets are sought through the development of new predictive tools to understand the combustion and flow physics, the introduction of high temperature materials to eliminate fuel film cooling and its associated combustion inefficiency, and improved component designs to optimize performance. Improved predictive technology is sought through the comparison of both local and global predictions with experimental data. Results indicate that modeling of the injector and combustion process in small rockets needs improvement. High temperature materials require the development of fabrication processes, a durability data base in both laboratory and rocket environments, and basic engineering property data such as strength, creep, fatigue, and work hardening properties at both room and elevated temperature. Promising materials under development include iridium-coated rhenium and a

  8. Small rocket research and technology

    NASA Astrophysics Data System (ADS)

    Schneider, Steven; Biaglow, James

    1993-11-01

    Small chemical rockets are used on nearly all space missions. The small rocket program provides propulsion technology for civil and government space systems. Small rocket concepts are developed for systems which encompass reaction control for launch and orbit transfer systems, as well as on-board propulsion for large space systems and earth orbit and planetary spacecraft. Major roles for on-board propulsion include apogee kick, delta-V, de-orbit, drag makeup, final insertions, north-south stationkeeping, orbit change/trim, perigee kick, and reboost. The program encompasses efforts on earth-storable, space storable, and cryogenic propellants. The earth-storable propellants include nitrogen tetroxide (NTO) as an oxidizer with monomethylhydrazine (MMH) or anhydrous hydrazine (AH) as fuels. The space storable propellants include liquid oxygen (LOX) as an oxidizer with hydrazine or hydrocarbons such as liquid methane, ethane, and ethanol as fuels. Cryogenic propellants are LOX or gaseous oxygen (GOX) as oxidizers and liquid or gaseous hydrogen as fuels. Improved performance and lifetime for small chemical rockets are sought through the development of new predictive tools to understand the combustion and flow physics, the introduction of high temperature materials to eliminate fuel film cooling and its associated combustion inefficiency, and improved component designs to optimize performance. Improved predictive technology is sought through the comparison of both local and global predictions with experimental data. Results indicate that modeling of the injector and combustion process in small rockets needs improvement. High temperature materials require the development of fabrication processes, a durability data base in both laboratory and rocket environments, and basic engineering property data such as strength, creep, fatigue, and work hardening properties at both room and elevated temperature. Promising materials under development include iridium-coated rhenium and a

  9. 77 FR 30227 - Small Business Size Regulations, Small Business Innovation Research (SBIR) Program and Small...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-22

    ... BUSINESS ADMINISTRATION 13 CFR Part 121 Small Business Size Regulations, Small Business Innovation Research (SBIR) Program and Small Business Technology Transfer (STTR) Program AGENCY: U.S. Small Business... to amend its regulations governing size and eligibility for the Small Business Innovation...

  10. 78 FR 11745 - Small Business Size Regulations, Small Business Innovation Research (SBIR) Program and Small...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-20

    ... / Wednesday, February 20, 2013 / Rules and Regulations#0;#0; ] SMALL BUSINESS ADMINISTRATION 13 CFR Part 121 RIN 3245-AG46 Small Business Size Regulations, Small Business Innovation Research (SBIR) Program and Small Business Technology Transfer (STTR) Program; Correction AGENCY: U.S. Small Business...

  11. VET and Small Business. Review of Research.

    ERIC Educational Resources Information Center

    Gibb, Jennifer

    Research since 1990 on vocational education and training (VET) and small business was reviewed. Special attention was paid to the research that has been conducted in the following categories identified in the Australian National Training Authority (ANTA) Small Business Policy Framework: context; role of government; approach to training; research…

  12. A translational research niche for small business innovation research grants.

    PubMed

    Handelsman, Karl

    2009-11-04

    The United States Congress will decide the future of the Small Business Innovation Research program in the coming months. Essential changes needed in the program and its unique role in translational research are discussed.

  13. Communicating Research to Small Drinking Water Systems: Dissemination by Researchers

    EPA Science Inventory

    This talk discusses the challenges of disseminating research relevant to small systems. The presentation discusses efforts by the U.S. EPA’s Office of Research and Development to effectively communicating drinking water information. In particular, communication approaches ...

  14. Small scale structure on cosmic strings

    SciTech Connect

    Albrecht, A.

    1989-10-30

    I discuss our current understanding of cosmic string evolution, and focus on the question of small scale structure on strings, where most of the disagreements lie. I present a physical picture designed to put the role of the small scale structure into more intuitive terms. In this picture one can see how the small scale structure can feed back in a major way on the overall scaling solution. I also argue that it is easy for small scale numerical errors to feed back in just such a way. The intuitive discussion presented here may form the basis for an analytic treatment of the small structure, which I argue in any case would be extremely valuable in filling the gaps in our resent understanding of cosmic string evolution. 24 refs., 8 figs.

  15. Small scale structure on cosmic strings

    NASA Technical Reports Server (NTRS)

    Albrecht, Andreas

    1989-01-01

    The current understanding of cosmic string evolution is discussed, and the focus placed on the question of small scale structure on strings, where most of the disagreements lie. A physical picture designed to put the role of the small scale structure into more intuitive terms is presented. In this picture it can be seen how the small scale structure can feed back in a major way on the overall scaling solution. It is also argued that it is easy for small scale numerical errors to feed back in just such a way. The intuitive discussion presented here may form the basis for an analytic treatment of the small scale structure, which argued in any case would be extremely valuable in filling the gaps in the present understanding of cosmic string evolution.

  16. Industry Research and Recommendations for Small Buildings and Small Portfolios

    SciTech Connect

    Langner, Rois; Hendron, Bob; Pless, Shanti; Huppert, Mark; Cochrane, Ric

    2013-12-01

    Small buildings have been left behind in the energy efficiency marketplace because financial and technical resources have flowed to larger commercial buildings. DOE's Building Technologies Office works with the commercial building industry to accelerate the uptake of energy efficiency technologies and techniques in existing and new commercial buildings (DOE 2013). BTO recognizes the SBSP sector'spotential for significant energy savings and the need for investments in resources that are tailored to this sector's unique needs. The industry research and recommendations described in this report identify potential approaches and strategic priorities that BTO could explore over the next 3-5 years that will support the implementation of high-potential energy efficiency opportunities for thisimportant sector. DOE is uniquely positioned to provide national leadership, objective information, and innovative tools, technologies, and services to support cost-effective energy savings in the fragmented and complex SBSP sector. Properly deployed, the DOE effort could enhance and complement current energy efficiency approaches. Small portfolios are loosely and qualitatively defined asportfolios of buildings that include only a small number of small buildings. This distinction is important because the report targets portfolio owners and managers who generally do not have staff and other resources to track energy use and pursue energy efficiency solutions.

  17. Small Wind Research Turbine: Final Report

    SciTech Connect

    Corbus, D.; Meadors, M.

    2005-10-01

    The Small Wind Research Turbine (SWRT) project was initiated to provide reliable test data for model validation of furling wind turbines and to help understand small wind turbine loads. This report will familiarize the user with the scope of the SWRT test and support the use of these data. In addition to describing all the testing details and results, the report presents an analysis of the test data and compares the SWRT test data to simulation results from the FAST aeroelastic simulation model.

  18. 78 FR 48537 - Small Business Innovation Research and Small Business Technology Transfer Programs...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-08

    ... ADMINISTRATION Small Business Innovation Research and Small Business Technology Transfer Programs... Administration (SBA) is publishing the Small Business Innovation Research (SBIR) and Small Business Technology... Business Administration, 409 Third Street SW., Washington, DC 20416; or send an email to...

  19. NASA Small Business Innovation Research program

    NASA Technical Reports Server (NTRS)

    Johnson, Harry W.

    1985-01-01

    NASA activities in the framework of the 11-agency federal Small Business Innovation Research program are outlined in tables and graphs and briefly characterized. Statistics on the program are given; the technical topics covered are listed; and the procedures involved in evaluating applications for support are discussed. A number of typical defects in proposals are indicated, and recommendations for avoiding them are provided.

  20. Precision Radiotherapy for Small Animal Research

    PubMed Central

    Matinfar, Mohammad; Iordachita, Iulian; Ford, Eric; Wong, John; Kazanzides, Peter

    2010-01-01

    Preclinical research using well characterized small animal models has provided tremendous benefits to medical research, enabling low cost, large scale trials with high statistical significance of observed effects. The goal of the Small Animal Radiation Research Platform (SARRP) is to make those models available for the development and evaluation of novel radiation therapies. SARRP demonstrates the capabilities of delivering high resolution, sub-millimeter, optimally planned conformal radiation with on-board cone-beam CT (CBCT) guidance. The system requires accurate calibration of the x-ray beam for both imaging and radiation treatment. In this paper, we present a novel technique using an x-ray camera for calibration of the treatment beam. This technique does not require precise positioning or calibration of the x-ray camera. PMID:18982656

  1. Small business innovation research program solicitation

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The National Aeronautics and Space Administration invites eligible small business concerns to submit Phase 1 proposals for its 1994 Small Business Innovation Research (SBIR) Program, which is described in this twelfth annual NASA SBIR Program Solicitation. The 1994 solicitation period for Phase 1 proposals begins April 4, 1994 and ends June 15, 1994. Eligible firms with research or research and development capabilities (R/R&D) in any of the listed topic and subtopic areas are encouraged to participate. Through SBIR, NASA seeks innovative concepts addressing the program needs described in the SBIR solicitation subtopics and offering commercial application potential. This document contains program background information, outlines eligibility requirements for SBIR participants, describes the three SBIR program phases, and provides the information qualified offerors need to prepare and submit responsive proposals.

  2. Structure and Gene-Silencing Mechanisms of Small Noncoding RNAs

    NASA Astrophysics Data System (ADS)

    Chu, Chia-Ying; Rana, Tariq M.

    Small (19-31-nucleotides) noncoding RNAs were identified in the past 10 years for their distinct function in gene silencing. The best known gene-silencing phenomenon, RNA interference (RNAi), is triggered in a sequence-specific manner by endogenously produced or exogenously introduced small doubled-stranded RNAs. As knowledge of the structure and function of the RNAi machinery has expanded, this phenomenon has become a powerful tool for biochemical research; it has enormous potential for therapeutics. This chapter summarizes significant aspects of three major classes of small noncoding, regulatory RNAs: small interfering RNAs (siRNAs), microRNAs (miRNAs), and Piwi-interacting RNAs (piRNAs). Here, we focus on the biogenesis of these small RNAs, their structural features and coupled effectors as well as the mechanisms of each small regulatory RNA pathway which reveal fascinating ways by which gene silencing is controlled and fine-tuned at an epigenetic level.

  3. Small business innovation research. Abstracts of 1988 phase 1 awards

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Non-proprietary proposal abstracts of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA are presented. Projects in the fields of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robots, computer sciences, information systems, data processing, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered.

  4. Funding big research with small money.

    PubMed

    Hickey, Joanne V; Koithan, Mary; Unruh, Lynn; Lundmark, Vicki

    2014-06-01

    This department highlights change management strategies that maybe successful in strategically planning and executing organizational change initiatives.With the goal of presenting practical approaches helpful to nurse leaders advancing organizational change, content includes evidence-based projects, tools,and resources that mobilize and sustain organizational change initiatives.In this article, the guest authors introduce crowd sourcing asa strategy for funding big research with small money.

  5. Small-scale coronal structure, part 3

    NASA Technical Reports Server (NTRS)

    Webb, David F.

    1986-01-01

    Recent observations and models pertaining specifically to solar coronal bright points (BPs) and generally to small-scale coronal structure are reviewed. Two questions were addressed: What is the degree of correspondence among various alleged signatures of BPs at different levels of atmosphere and what can PBs tell about the emerging flux spectrum of the sun?

  6. 75 FR 15756 - Small Business Innovation Research Program Policy Directive

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-30

    ... ADMINISTRATION RIN 3244-AF61 Small Business Innovation Research Program Policy Directive AGENCY: U.S. Small... announces a final amendment to the Small Business Innovation Research (SBIR) Program Policy Directive (PD... the Policy Directive; Small Business Innovation Research Program To: The Directors, Small...

  7. 77 FR 46909 - Small Business Innovation Research (SBIR) Program and Small Business Technology Transfer (STTR...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-06

    ... Innovation Research (SBIR) Program and Small Business Technology Transfer (STTR) Program Policy Directives... Small Business Innovation Research (SBIR) and Small Business Technology Transfer Program (STTR) Policy... technology@sba.gov . SUPPLEMENTARY INFORMATION: I. Background Information SBA is publishing Policy...

  8. Proton structure functions at small x

    SciTech Connect

    Hentschinski, Martin

    2015-11-03

    Proton structure functions are measured in electron-proton collision through inelastic scattering of virtual photons with virtuality Q on protons; x denotes the momentum fraction carried by the struck parton. Proton structure functions are currently described with excellent accuracy in terms of scale dependent parton distribution functions, defined in terms of collinear factorization and DGLAP evolution in Q. With decreasing x however, parton densities increase and are ultimately expected to saturate. In this regime DGLAP evolution will finally break down and non-linear evolution equations w.r.t x are expected to take over. In the first part of the talk we present recent result on an implementation of physical DGLAP evolution. Unlike the conventional description in terms of parton distribution functions, the former describes directly the Q dependence of the measured structure functions. It is therefore physical insensitive to factorization scheme and scale ambiguities. It therefore provides a more stringent test of DGLAP evolution and eases the manifestation of (non-linear) small x effects. It however requires a precise measurement of both structure functions F2 and FL, which will be only possible at future facilities, such as an Electron Ion Collider. In the second part we present a recent analysis of the small x region of the combined HERA data on the structure function F2. We demonstrate that (linear) next-to-leading order BFKL evolution describes the effective Pomeron intercept, determined from the combined HERA data, once a resummation of collinear enhanced terms is included and the renormalization scale is fixed using the BLM optimal scale setting procedure. We also provide a detailed description of the Q and x dependence of the full structure functions F2 in the small x region, as measured at HERA. As a result, predictions for the structure function FL are found to be in agreement with the existing HERA

  9. Proton structure functions at small x

    DOE PAGES

    Hentschinski, Martin

    2015-11-03

    Proton structure functions are measured in electron-proton collision through inelastic scattering of virtual photons with virtuality Q on protons; x denotes the momentum fraction carried by the struck parton. Proton structure functions are currently described with excellent accuracy in terms of scale dependent parton distribution functions, defined in terms of collinear factorization and DGLAP evolution in Q. With decreasing x however, parton densities increase and are ultimately expected to saturate. In this regime DGLAP evolution will finally break down and non-linear evolution equations w.r.t x are expected to take over. In the first part of the talk we present recentmore » result on an implementation of physical DGLAP evolution. Unlike the conventional description in terms of parton distribution functions, the former describes directly the Q dependence of the measured structure functions. It is therefore physical insensitive to factorization scheme and scale ambiguities. It therefore provides a more stringent test of DGLAP evolution and eases the manifestation of (non-linear) small x effects. It however requires a precise measurement of both structure functions F2 and FL, which will be only possible at future facilities, such as an Electron Ion Collider. In the second part we present a recent analysis of the small x region of the combined HERA data on the structure function F2. We demonstrate that (linear) next-to-leading order BFKL evolution describes the effective Pomeron intercept, determined from the combined HERA data, once a resummation of collinear enhanced terms is included and the renormalization scale is fixed using the BLM optimal scale setting procedure. We also provide a detailed description of the Q and x dependence of the full structure functions F2 in the small x region, as measured at HERA. As a result, predictions for the structure function FL are found to be in agreement with the existing HERA data.« less

  10. Electronic Structure of Small Lanthanide Containing Molecules

    NASA Astrophysics Data System (ADS)

    Kafader, Jared O.; Ray, Manisha; Topolski, Josey E.; Chick Jarrold, Caroline

    2016-06-01

    Lanthanide-based materials have unusual electronic properties because of the high number of electronic degrees of freedom arising from partial occupation of 4f orbitals, which make these materials optimal for their utilization in many applications including electronics and catalysis. Electronic spectroscopy of small lanthanide molecules helps us understand the role of these 4f electrons, which are generally considered core-like because of orbital contraction, but are energetically similar to valence electrons. The spectroscopy of small lanthanide-containing molecules is relatively unexplored and to broaden this understanding we have completed the characterization of small cerium, praseodymium, and europium molecules using photoelectron spectroscopy coupled with DFT calculations. The characterization of PrO, EuH, EuO/EuOH, and CexOy molecules have allowed for the determination of their electron affinity, the assignment of numerous anion to neutral state transitions, modeling of anion/neutral structures and electron orbital occupation.

  11. On the structure of small palladium particles

    SciTech Connect

    Herrera, R.; Avalos-Borja, M.; Schabes-Retchkiman, P.; Romeu, D.; Jose-Yacaman, M. . Inst. de Fisica); Ponce, F. )

    1989-09-01

    The study of small noble metal particles is becoming increasingly important in many fields in physics (1). The advent of high-resolution electron microscopy (HREM) has allowed a deeper understanding of structural aspects of small particles. This work reports the study of particles of palladium with a diameter less than 3 nm. Specimens were prepared by in-situ deposition of Pd onto thin carbon films under near-UHV conditions in the specimen preparation chamber. Faulted decahedral MTP was grown using a recursive (R) growth model which generates infinite, space-filling structures reproducing the structure of crystals, twinned particles and quasicrystals. R growth consists of the formation of a cluster by iterative addition of points (atoms) from a given star vector. The method presented sheds some light on a point that has been controversial in the past about the nature of MTP's. Some authors have claimed that these structures can be considered as FCC twins with a disclination to close the resulting gap. The fact that they can be obtained quite simply from stable smaller units appears to make the disclination unnecessary.

  12. Compilation of small ribosomal subunit RNA structures.

    PubMed Central

    Neefs, J M; Van de Peer, Y; De Rijk, P; Chapelle, S; De Wachter, R

    1993-01-01

    The database on small ribosomal subunit RNA structure contained 1804 nucleotide sequences on April 23, 1993. This number comprises 365 eukaryotic, 65 archaeal, 1260 bacterial, 30 plastidial, and 84 mitochondrial sequences. These are stored in the form of an alignment in order to facilitate the use of the database as input for comparative studies on higher-order structure and for reconstruction of phylogenetic trees. The elements of the postulated secondary structure for each molecule are indicated by special symbols. The database is available on-line directly from the authors by ftp and can also be obtained from the EMBL nucleotide sequence library by electronic mail, ftp, and on CD ROM disk. PMID:8332525

  13. 78 FR 59410 - Small Business Innovation Research and Small Business Technology Transfer Programs...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-26

    ... ADMINISTRATION Small Business Innovation Research and Small Business Technology Transfer Programs... period for the Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR... Street SW., Washington, DC 20416; or send an email to Technology@sba.gov . Highlight the information...

  14. Small Business Innovation Research, Post-Phase II Opportunity Assessment

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.; Steele, Gynelle C.

    2015-01-01

    This report outlines current Small Business Innovation Research (SBIR) Post-Phase II opportunity contract award results for the SBIR technology program from 2007 to 2011 for NASA's Aeronautics Research Mission Directorate (ARMD), Human Exploration and Operations Mission Directorate (HEOMD), Science Mission Directorate (SMD), and Space Technology Mission Directorate (STMD). The report provides guidelines for incorporating SBIR technology into NASA programs and projects and provides a quantitative overview of the post-Phase II award patterns that correspond with each mission directorate at NASA Glenn Research Center (GRC). In recent years, one of NASA's goals has been to not only transfer SBIR technologies to commercial industries, but to ensure that NASA mission directorates incorporate SBIR technologies into their program and project activities. Before incorporating technologies into MD programs, it is important to understand each mission directorate structure because each directorate has different objectives and needs. The directorate program structures follow.

  15. CSM parallel structural methods research

    NASA Technical Reports Server (NTRS)

    Storaasli, Olaf O.

    1989-01-01

    Parallel structural methods, research team activities, advanced architecture computers for parallel computational structural mechanics (CSM) research, the FLEX/32 multicomputer, a parallel structural analyses testbed, blade-stiffened aluminum panel with a circular cutout and the dynamic characteristics of a 60 meter, 54-bay, 3-longeron deployable truss beam are among the topics discussed.

  16. The structure of small metal clusters

    NASA Technical Reports Server (NTRS)

    Bauschlicher, C. W., Jr.; Pettersson, L. G. M.

    1986-01-01

    One metal atom surrounded by its 12 nearest neighbors is considered for both D(3d) (face-centered cubic-like) and D(3h) (hexagonal close-packed-like) geometries. For Al and Be, the neutral cluster and the positive and negative ions are considered for idealized (all bonds equal) and distorted geometries. The D(3d) geometry is found to be the lowest for Be13, while the D(3h) geometry is lower for Al13. This is the reverse of what is expected based upon the bulk metal structures, Be(hcp) and Al(fcc). Al13 is found to have only small distortions, while Be13 shows large distortions for both the D(3d) and D(3h) geometries. The ions have geometries which are similar to those found for the neutral systems. Both all-electron and effective core potential calculations were carried out on the X13 clusters; the agreement is very good.

  17. Small Drinking Water Systems Research and Development

    EPA Science Inventory

    In the United States, there are 152,002 public water systems (PWS) in operation. Of these, 97% are considered small systems under the Safe Drinking Water Act (SDWA)—meaning they serve 10,000 or fewer people. While many of these small systems consistently provide safe, relia...

  18. Can small institutes address some problems facing biomedical researchers?

    PubMed

    Sheetz, Michael P

    2014-11-01

    At a time of historically low National Institutes of Health funding rates and many problems with the conduct of research (unfunded mandates, disgruntled reviewers, and rampant paranoia), there is a concern that biomedical research as a profession is waning in the United States (see "Rescuing US biomedical research from its systemic flaws" by Alberts and colleagues in the Proceedings of the National Academy of Sciences). However, it is wonderful to discover something new and to tackle tough puzzles. If we could focus more of our effort on discussing scientific problems and doing research, then we could be more productive and perhaps happier. One potential solution is to focus efforts on small thematic institutes in the university structure that can provide a stimulating and supportive environment for innovation and exploration. With an open-lab concept, there are economies of scale that can diminish paperwork and costs, while providing greater access to state-of-the-art equipment. Merging multiple disciplines around a common theme can catalyze innovation, and this enables individuals to develop new concepts without giving up the credit they deserve, because it is usually clear who did the work. Small institutes do not solve larger systemic problems but rather enable collective efforts to address the noisome aspects of the system and foster an innovative community effort to address scientific problems.

  19. Small Molecule Docking from Theoretical Structural Models

    NASA Astrophysics Data System (ADS)

    Novoa, Eva Maria; de Pouplana, Lluis Ribas; Orozco, Modesto

    Structural approaches to rational drug design rely on the basic assumption that pharmacological activity requires, as necessary but not sufficient condition, the binding of a drug to one or several cellular targets, proteins in most cases. The traditional paradigm assumes that drugs that interact only with a single cellular target are specific and accordingly have little secondary effects, while promiscuous molecules are more likely to generate undesirable side effects. However, current examples indicate that often efficient drugs are able to interact with several biological targets [1] and in fact some dirty drugs, such as chlorpromazine, dextromethorphan, and ibogaine exhibit desired pharmacological properties [2]. These considerations highlight the tremendous difficulty of designing small molecules that both have satisfactory ADME properties and the ability of interacting with a limited set of target proteins with a high affinity, avoiding at the same time undesirable interactions with other proteins. In this complex and challenging scenario, computer simulations emerge as the basic tool to guide medicinal chemists during the drug discovery process.

  20. Standard methods for small hive beetle research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Small hive beetles, Aethina tumida, are parasites and scavengers of honey bee and other social bee colonies native to sub-Saharan Africa, where they are a minor pest only. In contrast, the beetles can be harmful parasites of European honey bee subspecies. Very rapidly after A. tumida established pop...

  1. Small Angle X-ray Scattering for Nanoparticle Research.

    PubMed

    Li, Tao; Senesi, Andrew J; Lee, Byeongdu

    2016-09-28

    X-ray scattering is a structural characterization tool that has impacted diverse fields of study. It is unique in its ability to examine materials in real time and under realistic sample environments, enabling researchers to understand morphology at nanometer and angstrom length scales using complementary small and wide angle X-ray scattering (SAXS, WAXS), respectively. Herein, we focus on the use of SAXS to examine nanoscale particulate systems. We provide a theoretical foundation for X-ray scattering, considering both form factor and structure factor, as well as the use of correlation functions, which may be used to determine a particle's size, size distribution, shape, and organization into hierarchical structures. The theory is expanded upon with contemporary use cases. Both transmission and reflection (grazing incidence) geometries are addressed, as well as the combination of SAXS with other X-ray and non-X-ray characterization tools. We conclude with an examination of several key areas of research where X-ray scattering has played a pivotal role, including in situ nanoparticle synthesis, nanoparticle assembly, and operando studies of catalysts and energy storage materials. Throughout this review we highlight the unique capabilities of X-ray scattering for structural characterization of materials in their native environment.

  2. A small grants program to involve communities in research.

    PubMed

    Thompson, Beti; Ondelacy, Stephanie; Godina, Ruby; Coronado, Gloria D

    2010-06-01

    A key tenet of community-based participatory research is that communities be involved in all facets of research, from defining the problem to identifying solutions, to assisting in the research, and to participating in the publication of results. In this study, we instituted a small grants program for community participation. A Request for Applications (RFA) was developed and circulated widely throughout the Valley. The RFA sought proposals to address health disparities in cancer education, prevention, and treatment among Hispanics living in the Valley. Funds available were $2,500.00-3,500.00 for 1 year's worth of work. To help evaluate the progress of the RFA community projects according to the perspectives of the Community Advisory Board (CAB), an open-ended, semi-structured interview was created and administered by a former staff member to CAB members. In 4 years, ten small grants proposed by community members were funded. Funds allocated totaled approximately $25,000. Interviews with CAB members indicated that the RFA program was perceived positively, but there were concerns about sustainability. Our community grants program resulted in the implementation of several novel cancer prevention programs conducted by a variety of community organizations in the Lower Yakima Valley.

  3. Development of the Research Platform of Small Autonomous Blimp Robot

    NASA Astrophysics Data System (ADS)

    Takaya, Toshihiko; Kawamura, Hidenori; Yamamoto, Masahito; Ohuchi, Azuma

    A blimp robot is attractive as an small flight robot and can float in the air by buoyancy and realize safe to the crash small flight with low energy and can movement for a long time compared with other flight robots with low energy and can movement for a long time compared with other flight robots. However, control of an airplane robot is difficult for the nonlinear characteristic exposed to inertia by the air flow in response to influence. Therefore, the applied research which carried out the maximum use of such in recent years a blimp robot's feature is prosperous. In this paper, we realized development of blimp robot for research which can be used general-purpose by carrying out clue division of the blimp robot body at a unit, and constituting and building for research of blimp robot, and application development. On the other hand, by developing a general-purpose blimp robot research platform, improvement in the research efficiency of many researchers can be attained, and further, research start of blimp robot becomes easy and contributes to development of research. We performed the experiments for the above-mentioned proof. 1. Checked basic keeping position performance and that various orbital operation was possible. And the unit exchange ease of software unit was checked by the experiment which exchanges the control layer of software for learning control from PID control, and carries out comparison of operation. 2. In order to check the exchange ease of hardware unit, the sensor was exchanged for the microphon from the camera, and control of operation was checked. 3. For the unit addition ease, the microphon which carries out sound detection with the picture detection with a camera was added, and control of operation was verified. 4. The unit exchange was carried out for the check of a function addition and the topological map generation experiment by addition of an ultrasonic sensor was conducted. Developed blimp robot for research mounted the exchange ease

  4. Undergraduate Research with a Small Radio Telescope

    NASA Astrophysics Data System (ADS)

    Fisher, P. L.; Williams, G. J.

    2001-11-01

    We describe the construction of a small radio telescope system at ULM and the role of radio astronomy in undergraduate education. The heart of the system is the Small Radio Telescope (SRT), which is a modified satellite TV antenna and custom receiver purchased from MIT Haystack Observatory. This telescope measures the brightness of many celestial objects at wavelengths near 21 cm. The system consists of various components to control dish movement, as well as perform analog to digital conversions allowing analysis of collected data. Undergraduate students have participated in the construction of the hardware and the task of interfacing the hardware to software on two GNU/Linux computer systems. The construction of the telescope and analysis of data allow the students to employ key concepts from mechanics, optics, electrodynamics, and thermodynamics, as well as computer and electronics skills. We will report preliminary results of solar observations conducted with this instrument and with the MIT Haystack Observatory 37m radio telescope. This work was supported by Louisiana Board of Regents grant LEQSF-ENH-UG-16, NASA/LaSPACE LURA R109139 and ULM Development Foundation Grant 97317.

  5. Small business innovation research: Program solicitation

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This, the seventh annual SBIR solicitation by NASA, describes the program, identifies eligibility requirements, outlines the required proposal format and content, states proposal preparation and submission requirements, describes the proposal evaluation and award selection process, and provides other information to assist those interested in participating in NASA's SBIR program. It also identifies the Technical Topics and Subtopics in which SBIR Phase 1 proposals are solicited in 1989. These Topics and Subtopics cover a broad range of current NASA interests, but do not necessarily include all areas in which NASA plans or currently conducts research. High-risk high pay-off innovations are desired.

  6. Structural evolution of small ruthenium cluster anions

    SciTech Connect

    Waldt, Eugen; Hehn, Anna-Sophia; Ahlrichs, Reinhart; Kappes, Manfred M.; Schooss, Detlef

    2015-01-14

    The structures of ruthenium cluster anions have been investigated using a combination of trapped ion electron diffraction and density functional theory computations in the size range from eight to twenty atoms. In this size range, three different structural motifs are found: Ru{sub 8}{sup −}–Ru{sub 12}{sup −} have simple cubic structures, Ru{sub 13}{sup −}–Ru{sub 16}{sup −} form double layered hexagonal structures, and larger clusters form close packed motifs. For Ru{sub 17}{sup −}, we find hexagonal close packed stacking, whereas octahedral structures occur for Ru{sub 18}{sup −}–Ru{sub 20}{sup −}. Our calculations also predict simple cubic structures for the smaller clusters Ru{sub 4}{sup −}–Ru{sub 7}{sup −}, which were not accessible to electron diffraction measurements.

  7. Small Hydropower Research and Development Technology Project

    SciTech Connect

    Blackmore, Mo

    2013-12-06

    The objective of this work was to investigate, develop, and validate the next generation of small hydroturbine generator designs that maximize the energy transfer from flowing water to electrical power generation. What resulted from this effort was the design of a new technology hydroturbine that Near Space Systems (NSS) has named the Star*Stream© Hydroturbine. Using a design that eliminates nearly all of the shortfalls of conventional hydroturbines, the Star*Stream© Hydroturbine employs a new mechanical-to-electrical energy transfer hydro design that operates without lubrication of any kind, and does not introduce foreign chemicals or particulate matter from oil or drive shaft seal degradation into the hydro ecology. In its unique configuration, the Star*Stream© Hydroturbine is nearly environmentally inert, without the negative aspects caused by interrupting the ecological continuity, i.e., disruptions to sedimentation, water quality, habitat changes, human displacement, fish migration, etc., - while it ensures dramatically reduced timeframes to project completion. While a remarkable reduction in LCOE resulting from application of the Star*Stream© Hydroturbine technology has been the core achievement of the this effort, there have been numerous technological breakthroughs from the development effort.

  8. Speckle imaging of solar small scale structure. 2: Study of small scale structure in active regions

    NASA Astrophysics Data System (ADS)

    von der Luehe, O.

    1994-01-01

    The speckle imaging technique which is described in the first paper of this series (von der Luehe 1993) was used to analyze time series of high angular resolution images of solar small scale structure at a wavelength of 585 nm in active regions with the 76 cm diameter vacuum tower telescope at National Solar Observatory (NSO)/Sac Peak. Two sets of reconstructed images with a field of 4 by 4 arcsec which cover a period of 36 min and 83 min were generated and analyzed. The image reconstructions are supplemented with simultaneous large field photographs taken within a 15 A passband centered on the Ca II K (3933) line. The prime objective of the observing program was the study of the structure and the dynamics of the continuum wavelength counterpart of facular points which appear with high contrast in the Ca pictures, i.e., continuum bright points (CBPs). In addition to CBPs, the reconstructions allow studying other small scale phenomena. Results of the studies are given.

  9. Structures of small bismuth cluster cations

    NASA Astrophysics Data System (ADS)

    Kelting, Rebecca; Baldes, Alexander; Schwarz, Ulrike; Rapps, Thomas; Schooss, Detlef; Weis, Patrick; Neiss, Christian; Weigend, Florian; Kappes, Manfred M.

    2012-04-01

    The structures of bismuth cluster cations in the range between 4 and 14 atoms have been assigned by a combination of gas phase ion mobility and trapped ion electron diffraction measurements together with density functional theory calculations. We find that above 8 atoms the clusters adopt prolate structures with coordination numbers between 3 and 4 and highly directional bonds. These open structures are more like those seen for clusters of semiconducting-in-bulk elements (such as silicon) rather than resembling the compact structures typical for clusters of metallic-in-bulk elements. An accurate description of bismuth clusters at the level of density functional theory, in particular of fragmentation pathways and dissociation energetics, requires taking spin-orbit coupling into account. For n = 11 we infer that low energy isomers can have fragmentation thresholds comparable to their structural interconversion barriers. This gives rise to experimental isomer distributions which are dependent on formation and annealing histories.

  10. Structural properties of small rhodium clusters

    SciTech Connect

    Soon, Yee Yeen; Yoon, Tiem Leong; Lim, Thong Leng

    2015-04-24

    We report a systematic study of the structural properties of rhodium clusters at the atomistic level. A novel global-minimum search algorithm, known as parallel tempering multicanonical basin hopping plus genetic algorithm (PTMBHGA), is used to obtain the geometrical structures with lowest minima at the semi-empirical level where Gupta potential is used to describe the atomic interaction among the rhodium atoms. These structures are then re-optimized at the density functional theory (DFT) level with exchange-correlation energy approximated by Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation (GGA). The structures are optimized for different spin multiplicities. The ones with lowest energies will be taken as ground-state structures. In most cases, we observe only minor changes in the geometry and bond length of the clusters as a result of DFT-level re-optimization. Only in some limited cases, the initial geometries obtained from the PTMBHGA are modified by the re-optimization. The variation of structural properties, such as ground-state geometry, symmetry and binding energy, with respect to the cluster size is studied and agreed well with other results available in the literature.

  11. Education and Training that Meets the Needs of Small Business: A Systematic Review of Research

    ERIC Educational Resources Information Center

    Dawe, Susan; Nguyen, Nhi

    2007-01-01

    Small businesses account for the great majority of businesses and half the private sector employment in Australia, but only one third provide structured training for their employees. This study, a systematic review of existing research, set out to find clear evidence of intervention strategies that meet small business needs in relation to the…

  12. Metacommunity structure in a small boreal stream network.

    PubMed

    Göthe, Emma; Angeler, David G; Sandin, Leonard

    2013-03-01

    Current ecological frameworks emphasize the relative importance of local and regional drivers for structuring species communities. However, most research has been carried out in systems with discrete habitat boundaries and a clear insular structure. Stream networks deviate from the insular structure and can serve as excellent model systems for studying hierarchical community dynamics over different temporal and spatial extents. We used benthic invertebrate data from streams in a small northern Swedish catchment to test whether metacommunity dynamics change between seasons, across spatial hierarchies (i.e. at the whole catchment scale vs. the scales of first-order and second/third-order sites within the catchment) and between stream-order groups. We assessed metacommunity structure as a function of three relevant dispersal dimensions (directional downstream processes, along-stream dispersal and overland dispersal). These dispersal dimensions were related to species groups with relevant dispersal traits (flying capacity, drift propensity) and dispersal capacities (weak vs. strong) to elucidate whether the observed spatial signals were due to dispersal limitation or mass effects. Results showed complex community organization that varied between seasons, with the scale of observation, and with stream order. The importance of spatial factors and specific dispersal dimensions was highly dependent on the time of sampling and the scale of observation. The importance of environmental factors was more consistent in our analyses, but their effect on species community structure peaked at first-order sites. Our analyses of species dispersal traits were not unequivocal, but indicated that both mass effects and dispersal limitation could simultaneously contribute to the spatial signal at the scale of the whole catchment through different dispersal pathways. We conclude that the study of hierarchically organized ecosystems uncovers complex patterns of metacommunity organization

  13. Building Research Cyberinfrastructure at Small/Medium Research Institutions

    ERIC Educational Resources Information Center

    Agee, Anne; Rowe, Theresa; Woo, Melissa; Woods, David

    2010-01-01

    A 2006 ECAR study defined cyberinfrastructure as the coordinated aggregate of "hardware, software, communications, services, facilities, and personnel that enable researchers to conduct advanced computational, collaborative, and data-intensive research." While cyberinfrastructure was initially seen as support for scientific and…

  14. Small Business Innovation Research Award Success Story: Proton Energy Systems

    SciTech Connect

    2011-04-01

    This success story describes Proton Energy Systems, a small business that designs and manufactures proton exchange membrane (PEM) electrolysis sytems to produce hydrogen from water. The U.S. Department of Energy's Fuel Cell Technologies Program has supported much of Proton's technology development through Small Business Innovation Research (SBIR) Awards and other non-SBIR funding.

  15. 77 FR 28520 - Small Business Size Regulations, Small Business Innovation Research (SBIR) Program and Small...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-15

    ... businesses to understand and a bright-line test by which small businesses can easily determine whether they..., bright-line test for SBIR and STTR applicants to apply when determining eligibility with respect to size... owns 33% or more of the company) in order to create a bright-line test for applicants; (2)...

  16. Small catalytic RNA: Structure, function and application

    SciTech Connect

    Monforte, J.A.

    1991-04-01

    We have utilized a combination of photochemical cross-linking techniques and site-directed mutagenesis to obtain secondary and tertiary structure information for the self-cleaving, self-ligating subsequence of RNA from the negative strand of Satellite Tobacco Ringspot Virus. We have found that the helical regions fold about a hinge to promoting four different possible tertiary interactions, creating a molecular of similar shape to a paperclip. A model suggesting that the paperclip'' and hammerhead'' RNAs share a similar three dimensional structure is proposed. We have used a self-cleaving RNA molecule related to a subsequence of plant viroids, a hammerhead,'' to study the length-dependent folding of RNA produced during transcription by RNA polymerase. We have used this method to determine the length of RNA sequestered within elongating E. coli and T7 RNA polymerase complexes. The data show that for E. coli RNA polymerase 12{plus minus}1 nucleotides are sequestered within the ternary complex, which is consistent with the presence of an RNA-DNA hybrid within the transcription bubble, as proposed by others. The result for T7 RNA polymerase differs from E. coli RNA polymerase, with only 10{plus minus}1 nucleotides sequestered within the ternary complex, setting a new upper limit for the minimum RNA-DNA required for a stable elongating complex. Comparisons between E. coli and T7 RNA polymerase are made. The relevance of the results to models or transcription termination, abortive initiation, and initiation to elongation mode transitions are discussed.

  17. Feasibility study of the Boeing Small Research Module (BSRM) concept

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The design, capabilities, and subsystem options for the Boeing Small Research Module (BSRM) are described. Specific scientific missions are defined based on NASA-Ames Research Center requirements and the BSRM capability to support these missions is discussed. Launch vehicle integration requirements and spacecraft operational features are also presented.

  18. Small catalytic RNA: Structure, function and application

    SciTech Connect

    Monforte, J.A.

    1991-04-01

    We have utilized a combination of photochemical cross-linking techniques and site-directed mutagenesis to obtain secondary and tertiary structure information for the self-cleaving, self-ligating subsequence of RNA from the negative strand of Satellite Tobacco Ringspot Virus. We have found that the helical regions fold about a hinge to promoting four different possible tertiary interactions, creating a molecular of similar shape to a paperclip. A model suggesting that the ``paperclip`` and ``hammerhead`` RNAs share a similar three dimensional structure is proposed. We have used a self-cleaving RNA molecule related to a subsequence of plant viroids, a ``hammerhead,`` to study the length-dependent folding of RNA produced during transcription by RNA polymerase. We have used this method to determine the length of RNA sequestered within elongating E. coli and T7 RNA polymerase complexes. The data show that for E. coli RNA polymerase 12{plus_minus}1 nucleotides are sequestered within the ternary complex, which is consistent with the presence of an RNA-DNA hybrid within the transcription bubble, as proposed by others. The result for T7 RNA polymerase differs from E. coli RNA polymerase, with only 10{plus_minus}1 nucleotides sequestered within the ternary complex, setting a new upper limit for the minimum RNA-DNA required for a stable elongating complex. Comparisons between E. coli and T7 RNA polymerase are made. The relevance of the results to models or transcription termination, abortive initiation, and initiation to elongation mode transitions are discussed.

  19. The Application of Reflexivity in Small Business Research and Implications for the Business Practitioner

    ERIC Educational Resources Information Center

    Harrison, Nigel; Kirkham, Janet

    2014-01-01

    This paper is based on a review of the lead author's research, which took the form of a self-narrative from a practitioner about the perceived realities of one small business and its owner. The paper explores the practical application of auto-ethnographic reflexive research methodologies and seeks to demonstrate that structured ways can be…

  20. Structure and stability of small TiO2 nanoparticles.

    PubMed

    Hamad, S; Catlow, C R A; Woodley, S M; Lago, S; Mejías, J A

    2005-08-25

    The effect of the nanostructure on the photochemistry of TiO2 is an active field of research owing to its applications in photocatalysis and photovoltaics. Despite this interest, little is known of the structure of small particles of this oxide with sizes at the nanometer length scale. Here we present a computational study that locates the global minima in the potential energy surface of Ti(n)O2n clusters with n = 1-15. The search procedure does not refer to any of the known TiO2 polymorphs, and is based on a novel combination of simulated annealing and Monte Carlo basin hopping simulations, together with genetic algorithm techniques, with the energy calculated by means of an interatomic potential. The application of several different methods increases our confidence of having located the global minimum. The stable structures are then refined by means of density functional theory calculations. The results from the two techniques are similar, although the methods based on interatomic potentials are unable to describe some subtle effects. The agreement is especially good for the larger particles, with n = 9-15. For these sizes the structures are compact, with a preference for a central octahedron and a surrounding layer of 4- and 5-fold coordinated Ti atoms, although there seems to be some energy penalty for particles containing the 5-fold coordinated metal atoms with square base pyramid geometry and dangling Ti=O bonds. The novel structures reported provide the basis for further computational studies of the effect of nanostructure on adsorption, photochemistry, and nucleation of this material.

  1. Small Business Innovation Research. Abstracts of Phase I awards, 1999

    SciTech Connect

    1999-12-01

    This booklet presents technical abstracts of Phase I awards made in Fiscal Year (FY) 1999 under the DOE Small Business Innovation Research (SBIR) program. SBIR research explores innovative concepts in important technological and scientific areas that can lead to valuable new technology and products. The work described in the abstracts is novel, high-risk research, but the benefits will also be potentially high if the objectives are met. Brief comments on the potential applications, as described by the awardee, are given after each abstract. Individuals and organizations, including venture capital and larger industrial firms, with an interest in the research described in any of the abstracts are encouraged to contact the appropriate small business directly.

  2. Multiple oligomeric structures of a bacterial small heat shock protein

    PubMed Central

    Mani, Nandini; Bhandari, Spraha; Moreno, Rodolfo; Hu, Liya; Prasad, B. V. Venkataram; Suguna, Kaza

    2016-01-01

    Small heat shock proteins are ubiquitous molecular chaperones that form the first line of defence against the detrimental effects of cellular stress. Under conditions of stress they undergo drastic conformational rearrangements in order to bind to misfolded substrate proteins and prevent cellular protein aggregation. Owing to the dynamic nature of small heat shock protein oligomers, elucidating the structural basis of chaperone action and oligomerization still remains a challenge. In order to understand the organization of sHSP oligomers, we have determined crystal structures of a small heat shock protein from Salmonella typhimurium in a dimeric form and two higher oligomeric forms: an 18-mer and a 24-mer. Though the core dimer structure is conserved in all the forms, structural heterogeneity arises due to variation in the terminal regions. PMID:27053150

  3. LEADERSHIP IN SMALL MILITARY UNITS--SOME RESEARCH FINDINGS.

    ERIC Educational Resources Information Center

    LANGE, CARL J.

    THE EFFECT OF A LEADER'S ACTIONS ON HIS FOLLOWERS IN SMALL MILITARY UNITS WAS THE SUBJECT OF SEVERAL RESEARCH STUDIES CONDUCTED TO EXPLORE THE NATURE OF THE LEADERSHIP PROCESS, WITH THE ULTIMATE GOAL OF DEVELOPING TRAINING THAT WOULD USE IMPROVED PRESENTATIONAL MATERIALS AND WOULD BE BASED ON LEADERSHIP DOCTRINE WITH DEMONSTRATED VALIDITY. THE…

  4. Feasibility study of the Boeing Small Research Module (BSRM) concept

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The design, capabilities, and subsystem options are described for the Boeing Small Research Module (BSRM). Specific scientific missions are defined and the BSRM capability to support these missions is discussed. Launch vehicle integration requirements and spacecraft operational features are also presented.

  5. Biomedical Research Experiences for Biology Majors at a Small College

    ERIC Educational Resources Information Center

    Stover, Shawn K.; Mabry, Michelle L.

    2010-01-01

    A program-level assessment of the biology curriculum at a small liberal arts college validates a previous study demonstrating success in achieving learning outcomes related to content knowledge and communication skills. Furthermore, research opportunities have been provided to complement pedagogical strategies and give students a more complete…

  6. On the relation between the small world structure and scientific activities.

    PubMed

    Ebadi, Ashkan; Schiffauerova, Andrea

    2015-01-01

    The modern science has become more complex and interdisciplinary in its nature which might encourage researchers to be more collaborative and get engaged in larger collaboration networks. Various aspects of collaboration networks have been examined so far to detect the most determinant factors in knowledge creation and scientific production. One of the network structures that recently attracted much theoretical attention is called small world. It has been suggested that small world can improve the information transmission among the network actors. In this paper, using the data on 12 periods of journal publications of Canadian researchers in natural sciences and engineering, the co-authorship networks of the researchers are created. Through measuring small world indicators, the small worldiness of the mentioned network and its relation with researchers' productivity, quality of their publications, and scientific team size are assessed. Our results show that the examined co-authorship network strictly exhibits the small world properties. In addition, it is suggested that in a small world network researchers expand their team size through getting connected to other experts of the field. This team size expansion may result in higher productivity of the whole team as a result of getting access to new resources, benefitting from the internal referring, and exchanging ideas among the team members. Moreover, although small world network is positively correlated with the quality of the articles in terms of both citation count and journal impact factor, it is negatively related with the average productivity of researchers in terms of the number of their publications.

  7. Small Radioisotope Power System at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Dugala, Gina M.; Fraeman, Martin; Frankford, David P.; Duven, Dennis; Shamkovich, Andrei; Ambrose, Hollis; Meer, David W.

    2012-01-01

    In April 2009, NASA Glenn Research Center (GRC) formed an integrated product team (IPT) to develop a Small Radioisotope Power System (SRPS) utilizing a single Advanced Stirling Convertor (ASC) with passive balancer for possible use by the International Lunar Network (ILN) program. The ILN program is studying the feasibility of implementing a multiple node seismometer network to investigate the internal lunar structure. A single ASC produces approximately 80 W(sub e) and could potentially supply sufficient power for that application. The IPT consists of Sunpower, Inc., to provide the single ASC with balancer, The Johns Hopkins University Applied Physics Laboratory (JHU/APL) to design an engineering model Single Convertor Controller (SCC) for an ASC with balancer, and NASA GRC to provide technical support to these tasks and to develop a simulated lunar lander test stand. A controller maintains stable operation of an ASC. It regulates the alternating current produced by the linear alternator of the convertor, provides a specified output voltage, and maintains operation at a steady piston amplitude and hot end temperature. JHU/APL also designed an ASC dynamic engine/alternator simulator to aid in the testing and troubleshooting of the SCC. This paper describes the requirements, design, and development of the SCC, including some of the key challenges and the solutions chosen to overcome those issues. In addition, it describes the plans to analyze the effectiveness of a passive balancer to minimize vibration from the ASC, characterize the effect of ASC vibration on a lunar lander, characterize the performance of the SCC, and integrate the single ASC, SCC, and lunar lander test stand to characterize performance of the overall system.

  8. Small business innovation research. Abstracts of completed 1987 phase 1 projects

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered.

  9. Research on the detection technology to dim and small target

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Chen, Feng; Huang, Jianming; Wei, Xiangquan

    2015-03-01

    With the development of Space Technology, the demand to Space Surveillance System is more urgent than before. The paper studies the dim and small target of long range. Firstly, it describes the research status of dim and small target abroad and the two detection principle of DBT and TBD. Secondly, it focuses on the higher-order correlation method, dynamic programming method and projection transformation method of TBD. Finally, it studies the image sequence simulation of different signal to noise ratio (SNR) with the real-time data from the aircraft in orbit. The image sequence is used to experimental verification. The test results show the dim and small target detection capability and applicable occasion of different methods. At the same time, it provides a new idea to the development of long-distance optical detector.

  10. Structural insights into the transport of small molecules across membranes

    PubMed Central

    Noinaj, Nicholas; Buchanan, Susan K.

    2014-01-01

    While hydrophobic small molecules often can freely permeate a lipid bilayer, ions and other polar molecules cannot and require transporters to mediate their transport. Recently, a number of important structures have been reported which have advanced our understanding of how membrane protein transporters function to transport small molecules. Structures of TbpA/B and HmuUV provided new insight into iron uptake by pathogenic bacteria while the structures of NarK, ASBT, and VcINDY revealed molecular details about the transport of nitrate, bile acids and dicarboxylates, respectively. The structure of the folate ECF transporter indicated that the S component likely undergoes a large conformational shift to mediate folate transport, while the cellulose synthase/transporter contains an elongated translocation pore for passage through the inner membrane. PMID:24681594

  11. Structural abnormalities of small resistance arteries in essential hypertension.

    PubMed

    Rizzoni, Damiano; Agabiti-Rosei, Enrico

    2012-06-01

    Regardless of the mechanisms that initiate the increase in blood pressure, the development of structural changes in the systemic vasculature is the end result of established hypertension. In essential hypertension, the small arteries smooth muscle cells are restructured around a smaller lumen, and there is no net growth of the vascular wall, while in some secondary forms of hypertension, a hypertrophic remodeling may be detected. Also, in non-insulin-dependent diabetes mellitus, a hypertrophic remodeling of subcutaneous small arteries is present. The results from our own group have suggested that indices of small resistance artery structure, such as the tunica media to internal lumen ratio, may have a strong prognostic significance in hypertensive patients, over and above all other known cardiovascular risk factors. Therefore, the regression of vascular alterations is an appealing goal of antihypertensive treatment. Different antihypertensive drugs seem to have different effect on vascular structure, both in human and in animal models of genetic and experimental hypertension. A complete normalization of small resistance artery structure is demonstrated in hypertensive patients, after long-term and effective therapy with ACE inhibitors, angiotensin II receptor blockers and calcium antagonists. Few data are available in diabetic hypertensive patients; however, blockade of the renin-angiotensin system seems to be effective in this regard. In conclusion, there are several pieces of evidence that suggest that small resistance artery structure may be considered an intermediate endpoint in the evaluation of the effects of antihypertensive therapy; however, there are presently no data available about the prognostic impact of the regression of vascular structural alterations in hypertension and diabetes.

  12. Defense Small Business Innovation Research Program (SBIR) FY 1983.

    DTIC Science & Technology

    1983-05-31

    matching networks for application in the frequency band below 30 MHz. The antenna should be light - weight, rapidly erectable and capable of operation while...munitions concealed within this terrain. m. More Efficient Utilization of Fuel in Light Trucks and Off-Road Vehi- cles (11) Current research is focusing on...affixed. The material must be light - * weight, small, and inexpensive to buy and install. d. Hard Coatings for Optical Systems (7) Broadband sensors

  13. Structural mechanics research at the Langley Research Center

    NASA Technical Reports Server (NTRS)

    Stephens, W. B.

    1976-01-01

    The contributions of NASA's Langley Research Center in areas of structural mechanics were traced from its NACA origins in 1917 to the present. The developments in structural mechanics technology since 1940 were emphasized. A brief review of some current research topics were discussed as well as anticipated near-term research projects.

  14. Unbiased structural search of small copper clusters within DFT

    NASA Astrophysics Data System (ADS)

    Cogollo-Olivo, Beatriz H.; Seriani, Nicola; Montoya, Javier A.

    2015-11-01

    The atomic structure of small Cu clusters with 3-6 atoms has been investigated by density functional theory and random search algorithm. New metastable structures have been found that lie merely tens of meV/atom above the corresponding ground state, and could therefore be present at thermodynamic equilibrium at room temperature or slightly above. Moreover, we show that the previously proposed linear configuration for Cu3 is in fact a local maximum of the energy. Finally, we argue that the random search algorithm also provides qualitative information about the attraction basin of each structure in the energy landscape.

  15. Insights to primitive replication derived from structures of small oligonucleotides

    NASA Technical Reports Server (NTRS)

    Smith, G. K.; Fox, G. E.

    1995-01-01

    Available information on the structure of small oligonucleotides is surveyed. It is observed that even small oligomers typically exhibit defined structures over a wide range of pH and temperature. These structures rely on a plethora of non-standard base-base interactions in addition to the traditional Watson-Crick pairings. Stable duplexes, though typically antiparallel, can be parallel or staggered and perfect complementarity is not essential. These results imply that primitive template directed reactions do not require high fidelity. Hence, the extensive use of Watson-Crick complementarity in genes rather than being a direct consequence of the primitive condensation process, may instead reflect subsequent selection based on the advantage of accuracy in maintaining the primitive genetic machinery once it arose.

  16. Structural and Spectroscopic Properties of Water Around Small Hydrophobic Solutes

    PubMed Central

    Montagna, Maria; Sterpone, Fabio; Guidoni, Leonardo

    2013-01-01

    We investigated the structural, dynamical and spectroscopic properties of water molecules around a solvated methane by means of Car-Parrinello molecular dynamics simulations. Despite their mobility, in the first-shell water molecules are dynamically displaced in a clathrate-like cage around the hydrophobic solute. No significant differences in water geometrical parameters, in molecular dipole moments or in hydrogen bonding properties are observed between in-shell and out-shell molecules, indicating that liquid water can accommodate a small hydrophobic solute without altering its structural properties. The calculated contribution of the first shell water molecules to the infrared spectra does not show significant differences with respect the bulk signal once the effects of the missing polarization of second-shell molecules has been taken into account. Small fingerprints of the clathrate-like structure appear in the vibrational density of states in the libration and OH stretching regions. PMID:22946539

  17. The development of small primate models for aging research.

    PubMed

    Fischer, Kathleen E; Austad, Steven N

    2011-01-01

    Nonhuman primate (NHP) aging research has traditionally relied mainly on the rhesus macaque. But the long lifespan, low reproductive rate, and relatively large body size of macaques and related Old World monkeys make them less than ideal models for aging research. Manifold advantages would attend the use of smaller, more rapidly developing, shorter-lived NHP species in aging studies, not the least of which are lower cost and the ability to do shorter research projects. Arbitrarily defining "small" primates as those weighing less than 500 g, we assess small, relatively short-lived species among the prosimians and callitrichids for suitability as models for human aging research. Using the criteria of availability, knowledge about (and ease of) maintenance, the possibility of genetic manipulation (a hallmark of 21st century biology), and similarities to humans in the physiology of age-related changes, we suggest three species--two prosimians (Microcebus murinus and Galago senegalensis) and one New World monkey (Callithrix jacchus)--that deserve scrutiny for development as major NHP models for aging studies. We discuss one other New World monkey group, Cebus spp., that might also be an effective NHP model of aging as these species are longer-lived for their body size than any primate except humans.

  18. Visualization of small scale structures on high resolution DEMs

    NASA Astrophysics Data System (ADS)

    Kokalj, Žiga; Zakšek, Klemen; Pehani, Peter; Čotar, Klemen; Oštir, Krištof

    2015-04-01

    Knowledge on the terrain morphology is very important for observation of numerous processes and events and digital elevation models are therefore one of the most important datasets in geographic analyses. Furthermore, recognition of natural and anthropogenic microrelief structures, which can be observed on detailed terrain models derived from aerial laser scanning (lidar) or structure-from-motion photogrammetry, is of paramount importance in many applications. In this paper we thus examine and evaluate methods of raster lidar data visualization for the determination (recognition) of microrelief features and present a series of strategies to assist selecting the preferred visualization of choice for structures of various shapes and sizes, set in varied landscapes. Often the answer is not definite and more frequently a combination of techniques has to be used to map a very diverse landscape. Researchers can only very recently benefit from free software for calculation of advanced visualization techniques. These tools are often difficult to understand, have numerous options that confuse the user, or require and produce non-standard data formats, because they were written for specific purposes. We therefore designed the Relief Visualization Toolbox (RVT) as a free, easy-to-use, standalone application to create visualisations from high-resolution digital elevation data. It is tailored for the very beginners in relief interpretation, but it can also be used by more advanced users in data processing and geographic information systems. It offers a range of techniques, such as simple hillshading and its derivatives, slope gradient, trend removal, positive and negative openness, sky-view factor, and anisotropic sky-view factor. All included methods have been proven to be effective for detection of small scale features and the default settings are optimised to accomplish this task. However, the usability of the tool goes beyond computation for visualization purposes, as sky

  19. Structural Design Strategies for Improved Small Overlap Crashworthiness Performance.

    PubMed

    Mueller, Becky C; Brethwaite, Andrew S; Zuby, David S; Nolan, Joseph M

    2014-11-01

    In 2012, the Insurance Institute for Highway Safety (IIHS) began a 64 km/h small overlap frontal crash test consumer information test program. Thirteen automakers already have redesigned models to improve test performance. One or more distinct strategies are evident in these redesigns: reinforcement of the occupant compartment, use of energy-absorbing fender structures, and the addition of engagement structures to induce vehicle lateral translation. Each strategy influences vehicle kinematics, posing additional challenges for the restraint systems. The objective of this two-part study was to examine how vehicles were modified to improve small overlap test performance and then to examine how these modifications affect dummy response and restraint system performance. Among eight models tested before and after design changes, occupant compartment intrusion reductions ranged from 6 cm to 45 cm, with the highest reductions observed in models with the largest number of modifications. All redesigns included additional occupant compartment reinforcement, one-third added structures to engage the barrier, and two modified a shotgun load path. Designs with engagement structures produced greater glance-off from the barrier and exhibited lower delta Vs but experienced more lateral outboard motion of the dummy. Designs with heavy reinforcement of the occupant compartment had higher vehicle accelerations and delta V. In three cases, these apparent trade-offs were not well addressed by concurrent changes in restraint systems and resulted in increased injury risk compared with the original tests. Among the 36 models tested after design changes, the extent of design changes correlated to structural performance. Half of the vehicles with the lowest intrusion levels incorporated aspects of all three design strategies. Vehicle kinematics and dummy and restraint system characteristics were similar to those observed in the before/after pairs. Different combinations of structural

  20. Structure design of the telescope for Small-JASMINE program

    NASA Astrophysics Data System (ADS)

    Utsunomiya, Shin; Yasuda, Susumu; Yano, Taihei; Niwa, Yoshito; Kobayashi, Yukiyasu; Kashima, Shingo; Goda, Naoteru; Yamada, Yoshiyuki

    2014-08-01

    Small-JASMINE program (Japan Astrometry Satellite Mission for INfrared Exploration) is one of applicants for JAXA (Japan Aerospace Exploration Agency) space science missions launched by Epsilon Launch Vehicles, and now being reviewed in the Science Committee of ISAS (Institute of Space and Astronautical Science), JAXA. Telescope of 300 mm aperture diameter will focus to the central region of the Milky Way Galactic. The target of Small-JASMINE is to obtain reliable measurements of extremely small stellar motions with the highest accuracy of 10 μ arcseconds and to provide precise distances and velocities of multitudes of stars up to 30,000 light years. Preliminary Structure design of Small- JASMINE has been done and indicates to satisfy all of requirements from the mission requirement, the system requirement, Epsilon Launch conditions and interfaces of the small science satellite standard bus. High margin of weight for the mission allows using all super invar structure that may reduce unforeseen thermal distortion risk especially caused by connection of different materials. Thermal stability of the telescope is a key issue and should be verified in a real model at early stage of the development.

  1. 2010 Thin Film & Small Scale Mechanical Behavior Gordon Research Conference

    SciTech Connect

    Dr. Thomas Balk

    2010-07-30

    Over the past decades, it has been well established that the mechanical behavior of materials changes when they are confined geometrically at least in one dimension to small scale. It is the aim of the 2010 Gordon Conference on 'Thin Film and Small Scale Mechanical Behavior' to discuss cutting-edge research on elastic, plastic and time-dependent deformation as well as degradation mechanisms like fracture, fatigue and wear at small scales. As in the past, the conference will benefit from contributions from fundamental studies of physical mechanisms linked to material science and engineering reaching towards application in modern applications ranging from optical and microelectronic devices and nano- or micro-electrical mechanical systems to devices for energy production and storage. The conference will feature entirely new testing methodologies and in situ measurements as well as recent progress in atomistic and micromechanical modeling. Particularly, emerging topics in the area of energy conversion and storage, such as material for batteries will be highlighted. The study of small-scale mechanical phenomena in systems related to energy production, conversion or storage offer an enticing opportunity to materials scientists, who can provide new insight and investigate these phenomena with methods that have not previously been exploited.

  2. Cyberinfrastructure to Support Collaborative Research Within Small Ecology Labs

    NASA Astrophysics Data System (ADS)

    Laney, C.; Jaimes, A.; Cody, R. P.; Kassin, A.; Salayandia, L.; Tweedie, C. E.

    2011-12-01

    Increasingly, ecological research programs addressing complex challenges are driving technological innovations that allow the acquisition and analysis of data collected over larger spatial scales and finer temporal resolutions. Many research labs are shifting from deploying technicians or students into the field to setting up automated sensors. These sensors can cost less on an individual basis, provide continuous and reliable data collection, and allow researchers to spend more time analyzing data and testing hypotheses. They can provide an enormous amount of complex information about an ecosystem. However, the effort to manage, analyze, and disseminate that information can be daunting. Small labs unfamiliar with these efforts may find their capacity to publish at competitive rates hindered by information management. Such labs would be well served by an easy to manage cyberinfrastructure (CI) that is organized in a modular, plug-and-play design and is amenable to a wide variety of data types. Its functionality would permit addition of new sensors and perform automated data analysis and visualization. Such a system would conceivably enhance access to data from small labs through web services, thereby improving the representation of smaller labs in scientific syntheses and enhancing the spatial and temporal coverage of such efforts. We present a CI that is designed to meet the needs of a small but heavily instrumented research site located within the USDA ARS Jornada Experimental Range in the northern Chihuahuan Desert. This site was constructed and is operated by the Systems Ecology Lab at the University of Texas at El Paso (UTEP), a relatively small and young lab. Researchers at the site study land-atmosphere carbon, water, and energy fluxes at a mixed creosote (Larrea tridentata) - mesquite (Prosopis glandulosa) shrubland. The site includes an eddy covariance tower built to AmeriFlux and FLUXNET specifications, a robotic cart that measures hyperspectral

  3. Small watershed-scale research and the challenges ahead

    NASA Astrophysics Data System (ADS)

    Larsen, M. C.; Glynn, P. D.

    2008-12-01

    For the past century, Federal mission science agencies (eg. USFS, NRCS, ARS, USGS) have had the long- term agency goals, infrastructure, and research staff to conduct research and data collection in small watersheds as well as support these activities for non-Federal partners. The National Science Foundation has been a strong partner with the Federal mission science agencies, through the LTER network, which is dependent on Federally supported research sites, and more recently with the emerging CUAHSI, WATERS, CZEN, and NEON initiatives. Much of the NSF-supported research builds on the foundations provided by their Federally supported partners, who sustain the long-term, extensive monitoring activity and research sites, including making long-term data available to all users via public interfaces. The future of these programs, and their enhancement/expansion to face the intensifying concurrent challenges of population growth, land-use change, and climate change, is dependent on a well-funded national commitment to basic science. Such a commitment will allow the scientific community to advance our understanding of these scientific challenges and to synthesize our understanding among research sites and at the national scale. Small watersheds serve as essential platforms where hypotheses can be tested, as sentinels for climate change, and as a basis for comparing and scaling up local information and syntheses to regional and continental scales. The science guides resource management and mitigation decisions and is fundamental to the development of predictive models. Furthermore, small-watershed research and monitoring programs are generally undervalued because many research questions that can be addressed now or in the future were not anticipated when the sites were initiated. Some examples include: 1) the quantification, characterization, and understanding of how emerging contaminants, personal care products, and endocrine disruptors affect organisms - substances that

  4. Proceedings of the First International Research Workshop for Process Improvement in Small Settings, 2005

    DTIC Science & Technology

    2006-01-01

    Small Settings .................................................................... 102 3.4 Business Benefits from Successful Process Measurements...i 4.1 Process Improvement as a Real Option to Extract Value from Project Failure in Context of Small Business ...unique issues of process improvement in small settings, including small teams, small projects, small organizations, and small businesses . Researchers

  5. Angular domain fluorescence imaging for small animal research

    NASA Astrophysics Data System (ADS)

    Vasefi, Fartash; Belton, Michelle; Kaminska, Bozena; Chapman, Glenn H.; Carson, Jeffrey J. L.

    2010-01-01

    We describe a novel macroscopic fluorescent imaging technique called angular domain fluorescence imaging (ADFI) applicable to the detection of fluorophores embedded in biological tissues. The method exploits the collimation detection capabilities of an angular filter array (AFA). The AFA uses the principle of acceptance angle filtration to extract minimally scattered photons emitted from fluorophores deep within tissue. Our goal was to develop an ADFI system for imaging near-infrared fluorescent markers for small animal imaging. According to the experimental results, the ADFI system offered higher resolution and contrast compared to a conventional lens and lens-pinhole fluorescent detection system. Furthermore, ADFI of a hairless mouse injected with a fluorescent bone marker revealed vertebral structural and morphometric data that correlated well with data derived from volumetric x-ray computed tomography images. The results suggested that ADFI is a useful technique for submillimeter mapping of the distribution of fluorescent biomarkers in small animals.

  6. Small Research Balloons in a Physics Course for Education Majors

    NASA Astrophysics Data System (ADS)

    Bruhweiler, F. C.; Verner, E.; Long, T.; Montanaro, E.

    2013-12-01

    At The Catholic Univ. of America, we teach an experimental physics course entitled Physics 240: The Sun-Earth Connection, which is designed for the undergraduate education major. The emphasis is on providing hands-on experience and giving the students an exciting experience in physics. As part of this course, in the Spring 2013 semester, we instituted a project to plan, build, launch, and retrieve a small (~1.3 kg) research balloon payload. The payload flown was a small GPS unit that sent its position to an Internet site, a small wide-angle high-resolution video camera, and an analog refrigerator thermometer placed in the field of view of the camera. All data were stored on the camera sim-card. Students faced the problems of flying a small research balloon in the congested, densely populated Northeast Corridor of the US. They used computer simulators available on the Web to predict the balloon path and flight duration given velocities for the Jet Stream and ground winds, as well as payload mass and amount of helium in the balloon. The first flight was extremely successful. The balloon was launched 140 km NW of Washington DC near Hagerstown, MD and touched down 10 miles (16 km) NW of York, PA, within 1.6 km of what was predicted. The balloon reached 73,000 ft (22,000 m) and the thermometer indicated temperatures as low as -70 degrees Fahrenheit (-57 C) during the flight. Further balloon flights are planned in conjunction with this course. Additional exercises and experiments will be developed centered around these flights. Besides learning that science can be exciting, students also learn that science is not always easily predictable, and that these balloon flights give an understanding of many of problems that go into real scientific space missions. This project is supported in part by an educational supplement to NASA grant NNX10AC56G

  7. Introduction to Small Telescope Research Communities of Practice

    NASA Astrophysics Data System (ADS)

    Genet, Russell M.

    2016-06-01

    Communities of practice are natural, usually informal groups of people who work together. Experienced members teach new members the “ropes.” Social learning theorist Etienne Wenger’s book, Communities of Practice: Learning, Meaning, and Identity, defined the field. There are, in astronomy, many communities of practice. One set of communities uses relatively small telescopes to observe brighter objects such as eclipsing binaries, intrinsically variable stars, transiting exoplanets, tumbling asteroids, and the occultation of background stars by asteroids and the Moon. Advances in low cost but increasingly powerful instrumentation and automation have greatly increased the research capabilities of smaller telescopes. These often professional-amateur (pro-am) communities engage in research projects that require a large number of observers as exemplified by the American Association of Variable Star Observers. For high school and community college students with an interest in science, joining a student-centered, small telescope community of practice can be both educational and inspirational. An example is the now decade-long Astronomy Research Seminar offered by Cuesta College in San Luis Obispo, California. Each student team is required to plan a project, obtain observations (either locally or via a remote robotic telescope), analyze their data, write a paper, and submit it for external review and publication. Well over 100 students, composed primarily of high school juniors and seniors, have been coauthors of several dozen published papers. Being published researchers has boosted these students’ educational careers with admissions to choice schools, often with scholarships. This seminar was recently expanded to serve multiple high schools with a volunteer assistant instructor at each school. The students meet regularly with their assistant instructor and also meet online with other teams and the seminar’s overall community college instructor. The seminar

  8. High quality, small molecule-activity datasets for kinase research

    PubMed Central

    Sharma, Rajan; Schürer, Stephan C.; Muskal, Steven M.

    2016-01-01

    Kinases regulate cell growth, movement, and death. Deregulated kinase activity is a frequent cause of disease. The therapeutic potential of kinase inhibitors has led to large amounts of published structure activity relationship (SAR) data. Bioactivity databases such as the Kinase Knowledgebase (KKB), WOMBAT, GOSTAR, and ChEMBL provide researchers with quantitative data characterizing the activity of compounds across many biological assays. The KKB, for example, contains over 1.8M kinase structure-activity data points reported in peer-reviewed journals and patents. In the spirit of fostering methods development and validation worldwide, we have extracted and have made available from the KKB 258K structure activity data points and 76K associated unique chemical structures across eight kinase targets. These data are freely available for download within this data note. PMID:27429748

  9. Structure of the Universe at Small and High Redshifts

    NASA Astrophysics Data System (ADS)

    Doroshkevich, A.; Turchaninov, V.

    1998-12-01

    The approximate theoretical description of the formation and evolution of the structure of the universe proposed by Demianski and Doroshkevich (1998) is compared with observed and simulated matter distribution at small and high redshifts. It is found that for the CDM-like power spectrum and suitable parameters of the cosmological model the effective matter compression reaches at small redshifts the observed scales Rwall ~20 - 25h^{-1}Mpc with the typical mean separation of wall-like elements DSLSS 50 - 70h^{-1}Mpc. We show that the same theoretical model explains well both the redshift, temperature and NHI distributions of absorption lines observed in the spectra of quasars at redshifts 2 <= z <= 3.5. The models with 0.3 <= Omega_m <= 0.5 give better description of the observed structure parameters.

  10. Secondary electron emission from surfaces with small structure

    NASA Astrophysics Data System (ADS)

    Dzhanoev, A. R.; Spahn, F.; Yaroshenko, V.; Lühr, H.; Schmidt, J.

    2015-09-01

    It is found that for objects possessing small surface structures with differing radii of curvature the secondary electron emission (SEE) yield may be significantly higher than for objects with smooth surfaces of the same material. The effect is highly pronounced for surface structures of nanometer scale, often providing a more than 100 % increase of the SEE yield. The results also show that the SEE yield from surfaces with structure does not show a universal dependence on the energy of the primary, incident electrons as it is found for flat surfaces in experiments. We derive conditions for the applicability of the conventional formulation of SEE using the simplifying assumption of universal dependence. Our analysis provides a basis for studying low-energy electron emission from nanometer structured surfaces under a penetrating electron beam important in many technological applications.

  11. Small-angle neutron scattering study of polymeric micellar structures

    SciTech Connect

    Wu, G.; Chu, B. ); Schneider, D.K. )

    1994-11-17

    Polymeric micellar structures formed by a PEO-PPO-PEO copolymer in o-xylene in the presence of water were investigated by small-angle neutron scattering. In order to reveal the detailed micellar structure, different contrasts among the micellar core, the micellar shell, and the dispersing medium (background) were constructed by selectively changing the protonated/deuterated combination of water and xylene. The micellar structure could be well described by a core-shell structure with the scattering behavior of the micellar shell being very similar to that of a star polymer. The solubilized water existed not only in the micellar core but also in the micellar shell. The volume fraction of a copolymer segments in the micellar shell was rather low, being of the order of 0.2. There seemed to be no sharp interface between the micellar core and the micellar shell. 25 refs., 11 figs., 4 tabs.

  12. Database on the structure of small ribosomal subunit RNA.

    PubMed Central

    Van de Peer, Y; Caers, A; De Rijk, P; De Wachter, R

    1998-01-01

    About 8600 complete or nearly complete sequences are now available from the Antwerp database on small ribosomal subunit RNA. All these sequences are aligned with one another on the basis of the adopted secondary structure model, which is corroborated by the observation of compensating substitutions in the alignment. Literature references, accession numbers and detailed taxonomic information are also compiled. The database can be consulted via the World Wide Web at URL http://rrna.uia.ac.be/ssu/ PMID:9399829

  13. Small data global existence for a fluid-structure model

    NASA Astrophysics Data System (ADS)

    Ignatova, Mihaela; Kukavica, Igor; Lasiecka, Irena; Tuffaha, Amjad

    2017-02-01

    We address the system of partial differential equations modeling motion of an elastic body inside an incompressible fluid. The fluid is modeled by the incompressible Navier-Stokes equations while the structure is represented by the damped wave equation with interior damping. The additional boundary stabilization γ, considered in our previous paper, is no longer necessary. We prove the global existence and exponential decay of solutions for small initial data in a suitable Sobolev space.

  14. Database on the structure of small ribosomal subunit RNA.

    PubMed Central

    Van de Peer, Y; Nicolaï, S; De Rijk, P; De Wachter, R

    1996-01-01

    The Antwerp database on small ribosomal subunit RNA offers over 4300 nucleotide sequences (August 1995). All these sequences are stored in the form of an alignment based on the adopted secondary structure model, which in turn is corroborated by the observation of compensating substitutions in the alignment. Besides the primary and secondary structure information, literature references, accession numbers and detailed taxonomic information are also compiled. The complete database is made available to the scientific community through anonymous ftp and World Wide Web(WWW). PMID:8594609

  15. Database on the structure of small ribosomal subunit RNA.

    PubMed Central

    Van de Peer, Y; Van den Broeck, I; De Rijk, P; De Wachter, R

    1994-01-01

    The database on small ribosomal subunit RNA structure contains (June 1994) 2824 nucleotide sequences. All these sequences are stored in the form of an alignment based on the adopted secondary structure model, which in turn is corroborated by the observation of compensating substitutions in the alignment. The complete database is made available to the scientific community through anonymous ftp on our server in Antwerp. A special effort was made to improve electronic retrieval and a program is supplied that allows to create different file formats. The database can also be obtained from the EMBL nucleotide sequence library. PMID:7524022

  16. Database on the structure of small ribosomal subunit RNA.

    PubMed Central

    Van de Peer, Y; Jansen, J; De Rijk, P; De Wachter, R

    1997-01-01

    The Antwerp database on small ribosomal subunit RNA now offers more than 6000 nucleotide sequences (August 1996). All these sequences are stored in the form of an alignment based on the adopted secondary structure model, which is corroborated by the observation of compensating substitutions in the alignment. Besides the primary and secondary structure information, literature references, accession numbers and detailed taxonomic information are also compiled. For ease of use, the complete database is made available to the scientific community via World Wide Web at URL http://rrna.uia.ac.be/ssu/ . PMID:9016516

  17. 48 CFR 227.7204 - Contracts under the Small Business Innovative Research Program.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Business Innovative Research Program. 227.7204 Section 227.7204 Federal Acquisition Regulations System... under the Small Business Innovative Research Program. When contracting under the Small Business Innovative Research Program, follow the procedures at 227-7104....

  18. Metastable structures and size effects in small group dynamics.

    PubMed

    Lauro Grotto, Rosapia; Guazzini, Andrea; Bagnoli, Franco

    2014-01-01

    In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological states that are characterized by a series of features: (1) they emerge as a consequence of the natural tendency of (both conscious and unconscious) emotions to combine into structured group patterns; (2) they have a certain degree of stability in time; (3) they tend to alternate so that the dissolution of one is rapidly followed by the emergence of another; (4) they can be described in qualitative terms according to the nature of the emotional mix that dominates the state, in structural terms by a kind of typical "leadership" pattern, and in "cognitive" terms by a set of implicit expectations that are helpful in explaining the group behavior (i.e., the group behaves "as if" it was assuming that). Here we adopt a formal approach derived from Socio-physics in order to explore some of the structural and dynamic properties of this small group dynamics. We will described data from an analytic DS model simulating small group interactions of agents endowed with a very simplified emotional and cognitive dynamic in order to assess the following main points: (1) are metastable collective states allowed to emerge in the model and if so, under which conditions in the parameter space? (2) can these states be differentiated in structural terms? (3) to what extent are the emergent dynamic features of the systems dependent of the system size? We will finally discuss possible future applications of the quantitative descriptions of the interaction structure in the small group clinical setting.

  19. Metastable structures and size effects in small group dynamics

    PubMed Central

    Lauro Grotto, Rosapia; Guazzini, Andrea; Bagnoli, Franco

    2014-01-01

    In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological states that are characterized by a series of features: (1) they emerge as a consequence of the natural tendency of (both conscious and unconscious) emotions to combine into structured group patterns; (2) they have a certain degree of stability in time; (3) they tend to alternate so that the dissolution of one is rapidly followed by the emergence of another; (4) they can be described in qualitative terms according to the nature of the emotional mix that dominates the state, in structural terms by a kind of typical “leadership” pattern, and in “cognitive” terms by a set of implicit expectations that are helpful in explaining the group behavior (i.e., the group behaves “as if” it was assuming that). Here we adopt a formal approach derived from Socio-physics in order to explore some of the structural and dynamic properties of this small group dynamics. We will described data from an analytic DS model simulating small group interactions of agents endowed with a very simplified emotional and cognitive dynamic in order to assess the following main points: (1) are metastable collective states allowed to emerge in the model and if so, under which conditions in the parameter space? (2) can these states be differentiated in structural terms? (3) to what extent are the emergent dynamic features of the systems dependent of the system size? We will finally discuss possible future applications of the quantitative descriptions of the interaction structure in the small group clinical

  20. Low-force magneto-rheological damper design for small-scale structural control experimentation

    NASA Astrophysics Data System (ADS)

    Winter, Benjamin D.; Velazquez, Antonio; Swartz, R. Andrew

    2015-03-01

    Experimental validation of novel structural control algorithms is a vital step in both developing and building acceptance for this technology. Small-scale experimental test-beds fulfill an important role in the validation of multiple-degree-offreedom (MDOF) and distributed semi-active control systems, allowing researchers to test the control algorithms, communication topologies, and timing-critical aspects of structural control systems that do not require full-scale specimens. In addition, small-scale building specimens can be useful in combined structural health monitoring (SHM) and LQG control studies, diminishing safety concerns during experiments by using benchtop-scale rather than largescale specimens. Development of such small-scale test-beds is hampered by difficulties in actuator construction. In order to be a useful analog to full-scale structures, actuators for small-scale test-beds should exhibit similar features and limitations as their full-scale counterparts. In particular, semi-active devices, such as magneto-rheological (MR) fluid dampers, with limited authority (versus active mass dampers) and nonlinear behavior are difficult to mimic over small force scales due to issues related to fluid containment and friction. In this study, a novel extraction-type small-force (0- 10 N) MR-fluid damper which exhibits nonlinear hysteresis similar to a full-scale, MR-device is proposed. This actuator is a key development to enable the function of a small-scale structural control test-bed intended for wireless control validation studies. Experimental validation of this prototype is conducted using a 3-story scale structure subjected to simulated single-axis seismic excitation. The actuator affects the structural response commanded by a control computer that executes an LQG state feedback control law and a modified Bouc-Wen lookup table that was previously developed for full-scale MR-applications. In addition, damper dynamic limitations are characterized and

  1. Small Business Innovation Research: Abstracts of Phase 1 awards, 1994

    SciTech Connect

    Not Available

    1994-12-31

    The Small Business Innovation Research (SBIR) program enables DOE to obtain effective, innovative solutions to important problems through the private sector, which has a commercial incentive to pursue the resulting technology and bring it to the marketplace. The growing number of awardees, many of them started in business in response to SBIR solicitations, is becoming a significant resource for the solution of high risk, high technology problems for the Department. As detailed here, this publication describes the technical efforts for SBIR Phase 1 awards in 1994. It is intended for the educated layman, and may be of particular interest to potential investors who wish to get in on the ground floor of exciting opportunities. Contained in this booklet are abstracts of the Phase 1 awards made in FY 1994 under the DOE SBIR program. The 212 Phase 1 projects described here were selected in a highly competitive process from a total of 2,276 grant applications received in response to the 1994 DOE annual SBIR Solicitation. The selections for awards were made on scientific and technical merit, as judged against the specific criteria listed in the Solicitation. Conclusions were reached on the basis of detailed reports returned by reviewers drawn from DOE laboratories, universities, private industry, and government. (Any discrepancies noted in prior DOE releases naming the firms selected for awards are due either to the firm changing its name after the award selection or to the firm not proceeding to a signed grant.) It is expected that between one-third and one-half of the Phase 1 projects will be continued into Phase 2. The work described in the abstracts is novel, high-risk research, but the benefits will also be potentially high if the objectives are met. Brief comments on the potential applications are given after each abstract. Individuals and organizations with an interest in the research described are encouraged to contact the appropriate small business directly.

  2. Engaging Undergraduate Students in Transiting Exoplanet Research with Small Telescopes

    NASA Astrophysics Data System (ADS)

    Stephens, Denise C.; Stoker, E.; Gaillard, C.; Ranquist, E.; Lara, P.; Wright, K.

    2013-10-01

    Brigham Young University has a relatively large undergraduate physics program with 300 to 360 physics majors. Each of these students is required to be engaged in a research group and to produce a senior thesis before graduating. For the astronomy professors, this means that each of us is mentoring at least 4-6 undergraduate students at any given time. For the past few years I have been searching for meaningful research projects that make use of our telescope resources and are exciting for both myself and my students. We first started following up Kepler Objects of Interest with our 0.9 meter telescope, but quickly realized that most of the transits we could observe were better analyzed with Kepler data and were false positive objects. So now we have joined a team that is searching for transiting planets, and my students are using our 16" telescope to do ground based follow-up on the hundreds of possible transiting planet candidates produced by this survey. In this presentation I will describe our current telescopes, the observational setup, and how we use our telescopes to search for transiting planets. I'll describe some of the software the students have written. I'll also explain how to use the NASA Exoplanet Archive to gather data on known transiting planets and Kepler Objects of Interests. These databases are useful for determining the observational limits of your small telescopes and teaching your students how to reduce and report data on transiting planets. Once that is in place, you are potentially ready to join existing transiting planet missions by doing ground-based follow-up. I will explain how easy it can be to implement this type of research at any high school, college, or university with a small telescope and CCD camera.

  3. Emerging applications of small angle solution scattering in structural biology.

    PubMed

    Chaudhuri, Barnali N

    2015-03-01

    Small angle solution X-ray and neutron scattering recently resurfaced as powerful tools to address an array of biological problems including folding, intrinsic disorder, conformational transitions, macromolecular crowding, and self or hetero-assembling of biomacromolecules. In addition, small angle solution scattering complements crystallography, nuclear magnetic resonance spectroscopy, and other structural methods to aid in the structure determinations of multidomain or multicomponent proteins or nucleoprotein assemblies. Neutron scattering with hydrogen/deuterium contrast variation, or X-ray scattering with sucrose contrast variation to a certain extent, is a convenient tool for characterizing the organizations of two-component systems such as a nucleoprotein or a lipid-protein assembly. Time-resolved small and wide-angle solution scattering to study biological processes in real time, and the use of localized heavy-atom labeling and anomalous solution scattering for applications as FRET-like molecular rulers, are amongst promising newer developments. Despite the challenges in data analysis and interpretation, these X-ray/neutron solution scattering based approaches hold great promise for understanding a wide variety of complex processes prevalent in the biological milieu.

  4. Structural dynamics branch research and accomplishments

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Summaries are presented of fiscal year 1989 research highlights from the Structural Dynamics Branch at NASA Lewis Research Center. Highlights from the branch's major work areas include aeroelasticity, vibration control, dynamic systems, and computation structural methods. A listing of the fiscal year 1989 branch publications is given.

  5. Electron Precipitation Associated with Small-Scale Auroral Structures

    NASA Astrophysics Data System (ADS)

    Michell, R.; Samara, M.; Grubbs, G. A., II; Hampton, D. L.; Bonnell, J. W.; Ogasawara, K.

    2014-12-01

    We present results from the Ground-to-Rocket Electrons Electrodynamics Correlative Experiment (GREECE) sounding rocket mission, where we combined high-resolution ground-based auroral imaging with high time-resolution precipitating electron measurements. The GREECE payload successfully launched from Poker Flat, Alaska on 03 March 2014 and reached an apogee of approximately 335 km. The narrow field-of-view auroral imaging was taken from Venetie, AK, which is directly under apogee. This enabled the small-scale auroral features at the magnetic footpoint of the rocket payload to be imaged in detail. The electron precipitation was measured with the Acute Precipitating Electron Spectrometer (APES) onboard the payload. Features in the electron data are matched up with their corresponding auroral structures and boundaries, enabling measurement of the exact electron distributions responsible for the specific small-scale auroral features. These electron distributions will then be used to infer what the potential electron acceleration processes were.

  6. Successes of Small Business Innovation Research at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Kim, Walter S.; Bitler, Dean W.; Prok, George M.; Metzger, Marie E.; Dreibelbis, Cindy L.; Ganss, Meghan

    2002-01-01

    This booklet of success stories highlights the NASA Glenn Research Center's accomplishments and successes by the Small Business Innovation Research (SBIR) and Small Business Technology Transfer (STTR) Programs. These success stories are the results of selecting projects that support NASA missions and also have high commercialization potential. Each success story describes the innovation accomplished, commercialization of the technology, and further applications and usages. This booklet emphasizes the integration and incorporation of technologies into NASA missions and other government projects. The company name and the NASA contact person are identified to encourage further usage and application of the SBIR developed technologies and also to promote further commercialization of these products.

  7. Structural basis of AMPK regulation by small molecule activators

    NASA Astrophysics Data System (ADS)

    Xiao, Bing; Sanders, Matthew J.; Carmena, David; Bright, Nicola J.; Haire, Lesley F.; Underwood, Elizabeth; Patel, Bhakti R.; Heath, Richard B.; Walker, Philip A.; Hallen, Stefan; Giordanetto, Fabrizio; Martin, Stephen R.; Carling, David; Gamblin, Steven J.

    2013-12-01

    AMP-activated protein kinase (AMPK) plays a major role in regulating cellular energy balance by sensing and responding to increases in AMP/ADP concentration relative to ATP. Binding of AMP causes allosteric activation of the enzyme and binding of either AMP or ADP promotes and maintains the phosphorylation of threonine 172 within the activation loop of the kinase. AMPK has attracted widespread interest as a potential therapeutic target for metabolic diseases including type 2 diabetes and, more recently, cancer. A number of direct AMPK activators have been reported as having beneficial effects in treating metabolic diseases, but there has been no structural basis for activator binding to AMPK. Here we present the crystal structure of human AMPK in complex with a small molecule activator that binds at a site between the kinase domain and the carbohydrate-binding module, stabilising the interaction between these two components. The nature of the activator-binding pocket suggests the involvement of an additional, as yet unidentified, metabolite in the physiological regulation of AMPK. Importantly, the structure offers new opportunities for the design of small molecule activators of AMPK for treatment of metabolic disorders.

  8. Nuclear Structure Research at Richmond

    SciTech Connect

    Beausang, Cornelius W.

    2015-04-30

    The goals for the final year were; (1) to continue ongoing efforts to develop and enhance GRETINA and work towards GRETA; (2) to investigate the structure of non-yrast states in shape transitional Sm and Gd nuclei; (3) to investigate the structure of selected light Cd nuclei; (4) to exploit the surrogate reaction technique to extract (n,f) cross sections for actinide nuclei, particularly the first measurement of the 236Pu and 237Pu(n,f) cross sections.

  9. Robust, high-throughput solution structural analyses by small angle X-ray scattering (SAXS)

    SciTech Connect

    Hura, Greg L.; Menon, Angeli L.; Hammel, Michal; Rambo, Robert P.; Poole II, Farris L.; Tsutakawa, Susan E.; Jenney Jr, Francis E.; Classen, Scott; Frankel, Kenneth A.; Hopkins, Robert C.; Yang, Sungjae; Scott, Joseph W.; Dillard, Bret D.; Adams, Michael W. W.; Tainer, John A.

    2009-07-20

    We present an efficient pipeline enabling high-throughput analysis of protein structure in solution with small angle X-ray scattering (SAXS). Our SAXS pipeline combines automated sample handling of microliter volumes, temperature and anaerobic control, rapid data collection and data analysis, and couples structural analysis with automated archiving. We subjected 50 representative proteins, mostly from Pyrococcus furiosus, to this pipeline and found that 30 were multimeric structures in solution. SAXS analysis allowed us to distinguish aggregated and unfolded proteins, define global structural parameters and oligomeric states for most samples, identify shapes and similar structures for 25 unknown structures, and determine envelopes for 41 proteins. We believe that high-throughput SAXS is an enabling technology that may change the way that structural genomics research is done.

  10. Small business innovation research: Abstracts of 1984. Phase 1 awards

    NASA Technical Reports Server (NTRS)

    1985-01-01

    On September 27, 1984, the National Aeronautics and Space Administration announced the selection of Phase I projects for the Small Business Innovation Research Program. These awards resulted from the evaluation of proposals submitted in response to the 1984 Program Solicitation, SBIR 84-1. In order to make available information on the technical content of the Phase I projects supported by the NASA SBIR Program, the abstracts of those proposals which resulted in awards of contracts are given. In addition, the name and address of the firm performing the work are given for those who may desired additional information about the project. Propulsion, aerodynamics, computer techniques, exobiology and composite materials are among the areas covered.

  11. Activities at the Smart Structures Research Institute

    NASA Astrophysics Data System (ADS)

    Gardiner, Peter T.

    1991-12-01

    Smart Structures and Materials technology will undoubtedly yield a wide range of new materials plus new sensing and actuation technologies and this will have a radical effect on current approaches to structural design. To meet the multi-disciplinary research challenge posed by this technology, the Smart Structures Research Institute (SSRI) has been established at the University of Strathclyde, Glasgow. This paper describes the background, current and planned activities and progress made in developing this new and very promising technology.

  12. Small-angle scattering and 3D structure interpretation.

    PubMed

    Trewhella, Jill

    2016-10-01

    This review focuses on advances in the application of solution small-angle scattering (SAS) in structural analysis of biomolecules and the complexes they form. Examples highlighted illustrate the unique contribution of SAS, using both X-rays and neutrons, in hybrid or integrative modelling methods. The increased information content when neutron scattering with contrast variation is used is a particular focus. Finally, progress toward an agreed reporting framework, the development of open data and model archives, and the importance of these initiatives is covered.

  13. Suggestions for Structuring a Research Article

    ERIC Educational Resources Information Center

    Klein, James D.; Reiser, Robert A.

    2014-01-01

    Researchers often experience difficulty as they attempt to prepare journal articles that describe their work. The purpose of this article is to provide researchers in the field of education with a series of suggestions as to how to clearly structure each section of a research manuscript that they intend to submit for publication in a scholarly…

  14. Aeropropulsion 1987. Session 2: Aeropropulsion Structures Research

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Aeropropulsion systems present unique problems to the structural engineer. The extremes in operating temperatures, rotational effects, and behaviors of advanced material systems combine into complexities that require advances in many scientific disciplines involved in structural analysis and design procedures. This session provides an overview of the complexities of aeropropulsion structures and the theoretical, computational, and experimental research conducted to achieve the needed advances.

  15. Atomistic and elastic analyses of defects and small structures. Annual report

    SciTech Connect

    Srolovitz, D.J.

    1995-11-01

    This past year, the authors have been working on several problems associated with defects in crystals and small structures. In one series of studies, they have been investigating the structure and energetics of surfaces as a function of surface orientation. One of the goals of their present research is to model non-topological defects in crystals and very small structures using elastic models as parameterized using atomistic calculations. In order to do this, they need to make sure that the atomistic and elastic models describe the same bulk system. To this end, they have developed a set of Embedded Atom Method interatomic potentials that produce an elastically isotopic perfect fcc crystal. In another project they evaluated the accuracy of the Free Energy Minimization Method. Another goal is to understand the effect of small system size on the behavior of materials. To that end, they have been performing simulations on the structure and thermodynamics of small spherical clusters of atoms and thin films, as a function of systems size. Recently, they have extended these calculations on small systems to alloys where appropriate focus is on surface segregation. Finally, they have been working to understand the effects of strain energy on the thermodynamics of a new class of highly distorted materials -- nested fullerenes.

  16. On the Relation between the Small World Structure and Scientific Activities

    PubMed Central

    Ebadi, Ashkan; Schiffauerova, Andrea

    2015-01-01

    The modern science has become more complex and interdisciplinary in its nature which might encourage researchers to be more collaborative and get engaged in larger collaboration networks. Various aspects of collaboration networks have been examined so far to detect the most determinant factors in knowledge creation and scientific production. One of the network structures that recently attracted much theoretical attention is called small world. It has been suggested that small world can improve the information transmission among the network actors. In this paper, using the data on 12 periods of journal publications of Canadian researchers in natural sciences and engineering, the co-authorship networks of the researchers are created. Through measuring small world indicators, the small worldiness of the mentioned network and its relation with researchers’ productivity, quality of their publications, and scientific team size are assessed. Our results show that the examined co-authorship network strictly exhibits the small world properties. In addition, it is suggested that in a small world network researchers expand their team size through getting connected to other experts of the field. This team size expansion may result in higher productivity of the whole team as a result of getting access to new resources, benefitting from the internal referring, and exchanging ideas among the team members. Moreover, although small world network is positively correlated with the quality of the articles in terms of both citation count and journal impact factor, it is negatively related with the average productivity of researchers in terms of the number of their publications. PMID:25780922

  17. Army/NASA small turboshaft engine digital controls research program

    NASA Technical Reports Server (NTRS)

    Sellers, J. F.; Baez, A. N.

    1981-01-01

    The emphasis of a program to conduct digital controls research for small turboshaft engines is on engine test evaluation of advanced control logic using a flexible microprocessor based digital control system designed specifically for research on advanced control logic. Control software is stored in programmable memory. New control algorithms may be stored in a floppy disk and loaded directly into memory. This feature facilitates comparative evaluation of different advanced control modes. The central processor in the digital control is an Intel 8086 16 bit microprocessor. Control software is programmed in assembly language. Software checkout is accomplished prior to engine test by connecting the digital control to a real time hybrid computer simulation of the engine. The engine currently installed in the facility has a hydromechanical control modified to allow electrohydraulic fuel metering and VG actuation by the digital control. Simulation results are presented which show that the modern control reduces the transient rotor speed droop caused by unanticipated load changes such as cyclic pitch or wind gust transients.

  18. Small-Scale Fabrication of Biomimetic Structures for Periodontal Regeneration

    PubMed Central

    Green, David W.; Lee, Jung-Seok; Jung, Han-Sung

    2016-01-01

    The periodontium is the supporting tissues for the tooth organ and is vulnerable to destruction, arising from overpopulating pathogenic bacteria and spirochaetes. The presence of microbes together with host responses can destroy large parts of the periodontium sometimes leading tooth loss. Permanent tissue replacements are made possible with tissue engineering techniques. However, existing periodontal biomaterials cannot promote proper tissue architectures, necessary tissue volumes within the periodontal pocket and a “water-tight” barrier, to become clinically acceptable. New kinds of small-scale engineered biomaterials, with increasing biological complexity are needed to guide proper biomimetic regeneration of periodontal tissues. So the ability to make compound structures with small modules, filled with tissue components, is a promising design strategy for simulating the anatomical complexity of the periodotium attachment complexes along the tooth root and the abutment with the tooth collar. Anatomical structures such as, intima, adventitia, and special compartments such as the epithelial cell rests of Malassez or a stellate reticulum niche need to be engineered from the start of regeneration to produce proper periodontium replacement. It is our contention that the positioning of tissue components at the origin is also necessary to promote self-organizing cell–cell connections, cell–matrix connections. This leads to accelerated, synchronized and well-formed tissue architectures and anatomies. This strategy is a highly effective preparation for tackling periodontitis, periodontium tissue resorption, and to ultimately prevent tooth loss. Furthermore, such biomimetic tissue replacements will tackle problems associated with dental implant support and perimimplantitis. PMID:26903872

  19. Small-Scale Fabrication of Biomimetic Structures for Periodontal Regeneration.

    PubMed

    Green, David W; Lee, Jung-Seok; Jung, Han-Sung

    2016-01-01

    The periodontium is the supporting tissues for the tooth organ and is vulnerable to destruction, arising from overpopulating pathogenic bacteria and spirochaetes. The presence of microbes together with host responses can destroy large parts of the periodontium sometimes leading tooth loss. Permanent tissue replacements are made possible with tissue engineering techniques. However, existing periodontal biomaterials cannot promote proper tissue architectures, necessary tissue volumes within the periodontal pocket and a "water-tight" barrier, to become clinically acceptable. New kinds of small-scale engineered biomaterials, with increasing biological complexity are needed to guide proper biomimetic regeneration of periodontal tissues. So the ability to make compound structures with small modules, filled with tissue components, is a promising design strategy for simulating the anatomical complexity of the periodotium attachment complexes along the tooth root and the abutment with the tooth collar. Anatomical structures such as, intima, adventitia, and special compartments such as the epithelial cell rests of Malassez or a stellate reticulum niche need to be engineered from the start of regeneration to produce proper periodontium replacement. It is our contention that the positioning of tissue components at the origin is also necessary to promote self-organizing cell-cell connections, cell-matrix connections. This leads to accelerated, synchronized and well-formed tissue architectures and anatomies. This strategy is a highly effective preparation for tackling periodontitis, periodontium tissue resorption, and to ultimately prevent tooth loss. Furthermore, such biomimetic tissue replacements will tackle problems associated with dental implant support and perimimplantitis.

  20. Extreme events and small-scale structure in computational turbulence

    NASA Astrophysics Data System (ADS)

    Zhai, X. M.; Yeung, P. K.; Sreenivasan, K. R.

    2015-11-01

    Detailed analyses have been made of data from a direct numerical simulation of turbulence on a periodic domain with 81923 grid points designed to improve our understanding of small-scale structure and intermittency. At the Reynolds number of this simulation (1300 based on the Taylor scale) extreme events of dissipation and enstrophy as large as 105 times the mean value are observed. These events are shown to possess a form that is different from similar events at low Reynolds numbers. Extreme vorticity appears to be ``chunky'' in character, in contrast to elongated vortex tubes at moderately large amplitudes commonly reported in the literature. We track the temporal evolution of these extreme events and find that they are generally short-lived, which suggests frequent sampling on-the-fly is useful. Extreme magnitudes of energy dissipation rate and enstrophy are essentially coincident in space and remain so during their evolution. Numerical tests show sensitivity to small-scale resolution and sampling but not machine precision. The connections expected between indicators of fine-scale intermittency such as acceleration statistics and the anomalous scaling of high-order velocity structure functions are also investigated. Supported by NSF Grant ACI-1036170 (Track 1 Petascale Resource Allocations Program).

  1. Small UAV Research and Evolution in Long Endurance Electric Powered Vehicles

    NASA Technical Reports Server (NTRS)

    Logan, Michael J.; Chu, Julio; Motter, Mark A.; Carter, Dennis L.; Ol, Michael; Zeune, Cale

    2007-01-01

    This paper describes recent research into the advancement of small, electric powered unmanned aerial vehicle (UAV) capabilities. Specifically, topics include the improvements made in battery technology, design methodologies, avionics architectures and algorithms, materials and structural concepts, propulsion system performance prediction, and others. The results of prototype vehicle designs and flight tests are discussed in the context of their usefulness in defining and validating progress in the various technology areas. Further areas of research need are also identified. These include the need for more robust operating regimes (wind, gust, etc.), and continued improvement in payload fraction vs. endurance.

  2. Small Radioisotope Power System Testing at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Dugala, Gina; Bell, Mark; Oriti, Salvatore; Fraeman, Martin; Frankford, David; Duven, Dennis

    2013-01-01

    In April 2009, NASA Glenn Research Center (GRC) formed an integrated product team (IPT) to develop a Small Radioisotope Power System (SRPS) utilizing a single Advanced Stirling Convertor (ASC) with passive balancer. A single ASC produces approximately 80 We making this system advantageous for small distributed lunar science stations. The IPT consists of Sunpower, Inc., to provide the single ASC with a passive balancer, The Johns Hopkins University Applied Physics Laboratory (JHUAPL) to design an engineering model Single Convertor Controller (SCC) for an ASC with a passive balancer, and NASA GRC to provide technical support to these tasks and to develop a simulated lunar lander test stand. The single ASC with a passive balancer, simulated lunar lander test stand, and SCC were delivered to GRC and were tested as a system. The testing sequence at GRC included SCC fault tolerance, integration, electromagnetic interference (EMI), vibration, and extended operation testing. The SCC fault tolerance test characterized the SCCs ability to handle various fault conditions, including high or low bus power consumption, total open load or short circuit, and replacing a failed SCC card while the backup maintains control of the ASC. The integrated test characterized the behavior of the system across a range of operating conditions, including variations in cold-end temperature and piston amplitude, including the emitted vibration to both the sensors on the lunar lander and the lunar surface. The EMI test characterized the AC and DC magnetic and electric fields emitted by the SCC and single ASC. The vibration test confirms the SCCs ability to control the single ASC during launch. The extended operation test allows data to be collected over a period of thousands of hours to obtain long term performance data of the ASC with a passive balancer and the SCC. This paper will discuss the results of each of these tests.

  3. Shielding considerations for the small animal radiation research platform (SARRP).

    PubMed

    Sayler, Elaine; Dolney, Derek; Avery, Stephen; Koch, Cameron

    2013-05-01

    The Small Animal Radiation Research Platform (SARRP) is a commercially available platform designed to deliver conformal, image-guided radiation to small animals using a dual-anode kV x-ray source. At the University of Pennsylvania, a free-standing 2 m enclosure was designed to shield the SARRP according to federal code regulating cabinet x-ray systems. The initial design consisted of 4.0-mm-thick lead for all secondary barriers and proved wholly inadequate. Radiation levels outside the enclosure were 15 times higher than expected. Additionally, the leakage appeared to be distributed broadly within the enclosure, so concern arose that a subject might receive significant doses outside the intended treatment field. Thus, a detailed analysis was undertaken to identify and block all sources of leakage. Leakage sources were identified by Kodak X-OmatV (XV) film placed throughout the enclosure. Radiation inside the enclosure was quantified using Gafchromic film. Outside the enclosure, radiation was measured using a survey meter. Sources of leakage included (1) an unnecessarily broad beam exiting the tube, (2) failure of the secondary collimator to confine the primary beam entirely, (3) scatter from the secondary collimator, (4) lack of beam-stop below the treatment volume, and (5) incomplete shielding of the x-ray tube. The exit window was restricted, and a new collimator was designed to address problems (1-3). A beam-stop and additional tube shielding were installed. These modifications reduced internal scatter by more than 100-fold. Radiation outside the enclosure was reduced to levels compliant with federal regulations, provided the SARRP is operated using tube potentials of 175 kV or less. In addition, these simple and relatively inexpensive modifications eliminate the possibility of exposing a larger animal (such as a rat) to significant doses outside the treatment field.

  4. Advances in structure elucidation of small molecules using mass spectrometry

    PubMed Central

    Fiehn, Oliver

    2010-01-01

    The structural elucidation of small molecules using mass spectrometry plays an important role in modern life sciences and bioanalytical approaches. This review covers different soft and hard ionization techniques and figures of merit for modern mass spectrometers, such as mass resolving power, mass accuracy, isotopic abundance accuracy, accurate mass multiple-stage MS(n) capability, as well as hybrid mass spectrometric and orthogonal chromatographic approaches. The latter part discusses mass spectral data handling strategies, which includes background and noise subtraction, adduct formation and detection, charge state determination, accurate mass measurements, elemental composition determinations, and complex data-dependent setups with ion maps and ion trees. The importance of mass spectral library search algorithms for tandem mass spectra and multiple-stage MS(n) mass spectra as well as mass spectral tree libraries that combine multiple-stage mass spectra are outlined. The successive chapter discusses mass spectral fragmentation pathways, biotransformation reactions and drug metabolism studies, the mass spectral simulation and generation of in silico mass spectra, expert systems for mass spectral interpretation, and the use of computational chemistry to explain gas-phase phenomena. A single chapter discusses data handling for hyphenated approaches including mass spectral deconvolution for clean mass spectra, cheminformatics approaches and structure retention relationships, and retention index predictions for gas and liquid chromatography. The last section reviews the current state of electronic data sharing of mass spectra and discusses the importance of software development for the advancement of structure elucidation of small molecules. Electronic supplementary material The online version of this article (doi:10.1007/s12566-010-0015-9) contains supplementary material, which is available to authorized users. PMID:21289855

  5. Research needs in aerospace structural dynamics

    NASA Technical Reports Server (NTRS)

    Amos, A. K.; Goetz, R. C.

    1979-01-01

    The perspective of a NASA Ad Hoc Study Committee on future research needs in structural dynamics within the aerospace industry is presented. It identifies the common aspects of the design process across the industry and establishes the role of structural dynamics in it through a discussion of various design considerations having their basis in structural dynamics. The specific structural dynamics issues involved in these considerations are identified and assessed as to their current technological status and trends. Projections of future requirements based on this assessment are made and areas of research to meet them are identified.

  6. Earthquake Forecast Science Research with a Small Satellite

    NASA Astrophysics Data System (ADS)

    Jason, Susan; da Silva Curiel, Alex; Pulinets, Sergey; Sweeting, Martin, , Sir

    Reliable, repeatable Earthquake forecast is a subject surrounded by controversy and scepticism. What is clear, is that reliable forecast could be the single most effective tool for earthquake disaster management. Roughly a third of the world's population live in areas that are at risk and, every year since the beginning of the twentieth century earthquakes have caused an average of 20,000 deaths [1]. The economic loss in the 1995 Kobe, Japan earthquake was greater than US100 billion [2]. Substantial progress has been made on the development of methods for earthquake hazard analysis on a timescale of a few decades. However, the forecast of specific earthquakes on timescales of a few years to a few days is a difficult problem. It has been proposed that satellites and ground-based facilities may detect earthquake precursors in the ionosphere a few hours or days before the main shock. This hypothesis is now backed by a physical model, derived by the Russian Academy of Sciences from statistical studies and an understanding of the main morphological features of seismo-ionospheric precursors, which allows them to be separated from background ionospheric variability. The main problems now are lack of regular global data and limited funding for what is considered to be financially risky research. Low-cost, small satellites offer a solution to these problems. A 100 kg class SSTL enhanced microsatellite, carrying a RAS topside sounder and complimentary payload, will be used to make regular measurements over seismically active zones around the globe. The low cost of the spacecraft offers a financially low-risk approach to the next step in this invaluable research. The spacecraft will make ionospheric measurements for systematic research into the proposed precursors. The aims will be to confirm or refute the hypothesis; define their reliability and reproducibility; and enable further scientific understanding of their mechanisms. In addition, forecasting of the magnitude of the

  7. Research progress in the treatment of small cell lung cancer

    PubMed Central

    Qiu, Yan-fang; Liu, Zhi-gang; Yang, Wen-juan; Zhao, Yu; Tang, Jiao; Tang, Wei-zhi; Jin, Yi; Li, Fang; Zhong, Rui; Wang, Hui

    2017-01-01

    Small cell lung cancer (SCLC) accounts for approximately 10-15% of all lung cancers. No significant improvement has been made for patients with SCLC in the past several decades. The main progresses were the thoracic radiation and prophylactic cranial irradiation (PCI) that improved the patient survival rate. For patients with limited disease and good performance status (PS), concurrent chemoradiotherapy (CCRT) followed by PCI should be considered. For extensive disease, the combination of etoposide and platinum-based chemotherapy remains the standard treatment and consolidative thoracic radiotherapy is beneficial for patients who have a significant respond to initial chemotherapy. However, the prognosis still remains poor. Recently, efforts have been focused on molecular targets and immunotherapy. But numerous molecular targets methods have failed to show a significant clinical benefit in patients with SCLC. It is anticipated that further development of research will depend on the on-going trials for molecular targeted therapy and immunotherapy which are promising and may improve the outcomes for SCLC in the next decade. PMID:28123595

  8. Pervasive small-scale structure in molecular clouds

    NASA Technical Reports Server (NTRS)

    Martin, B.; Lada, E.

    1986-01-01

    An unbiased CO survey of molecular cloud cores was completed, and the profiles were analyzed within the context of a model for emission from clumpy clouds. It was found that all sources observed contain a significant amount of structure that is not resolved with our 2.3-arcmin beam, and that the parameters which describe the degree of clumping span a remarkably narrow range of the possible values. We studied two separate samples of cloud cores: a large sample of warm cores from the Massachusetts-Stony Brook 12CO survey of the first galactic quadrant, and a sample of cool cores in the Taurus dark clouds chosen primarily on the basis of H2CO emission. We observed all sources in the 1-0 transition of 12CO and 13CO with the 5-m telescope of the Millimeter Wave Observatory. The 12CO/13CO ratios can be explained if there is unresolved structure giving rise to significant variations of opacity across the beam. Our model cloud consists of a large number of identical clumps distributed randomly in the beam. These clumps have velocity widths v small compared to the width of the observed profile, which is determined by the relative motion of the clumps. The entire cloud is isothermal and in local thermodynamic equilibrium. With these assumptions the intensity and linewidth ratios depend on three parameters: the abundance ratio; the peak 13CO opacity through a single clump, tau(0); and the average number of clumps on a line of sight N. Small tau(0) and large N correspond to the microturbulent limit, which is indistinguishable from a uniform gas distribution. In the other extreme, large tau(0) and snall N, at a given velocity at most one clump contributes to the profile on each line of sight. A figure is presented which shows the model parameters which reproduce the measured intensity and linewidth ratios for the sample of warm cores, assuming an abundance ratio of 75.

  9. A design guide and specification for small explosive containment structures

    SciTech Connect

    Marchand, K.A.; Cox, P.A.; Polcyn, M.A.

    1994-12-01

    The design of structural containments for testing small explosive devices requires the designer to consider the various aspects of the explosive loading, i.e., shock and gas or quasistatic pressure. Additionally, if the explosive charge has the potential of producing damaging fragments, provisions must be made to arrest the fragments. This may require that the explosive be packed in a fragment attenuating material, which also will affect the loads predicted for containment response. Material also may be added just to attenuate shock, in the absence of fragments. Three charge weights are used in the design. The actual charge is used to determine a design fragment. Blast loads are determined for a {open_quotes}design charge{close_quotes}, defined as 125% of the operational charge in the explosive device. No yielding is permitted at the design charge weight. Blast loads are also determined for an over-charge, defined as 200% of the operational charge in the explosive device. Yielding, but no failure, is permitted at this over-charge. This guide emphasizes the calculation of loads and fragments for which the containment must be designed. The designer has the option of using simplified or complex design-analysis methods. Examples in the guide use readily available single degree-of-freedom (sdof) methods, plus static methods for equivalent dynamic loads. These are the common methods for blast resistant design. Some discussion of more complex methods is included. Generally, the designer who chooses more complex methods must be fully knowledgeable in their use and limitations. Finally, newly fabricated containments initially must be proof tested to 125% of the operational load and then inspected at regular intervals. This specification provides guidance for design, proof testing, and inspection of small explosive containment structures.

  10. Structural Equation Modeling in Rehabilitation Counseling Research

    ERIC Educational Resources Information Center

    Chan, Fong; Lee, Gloria K.; Lee, Eun-Jeong; Kubota, Coleen; Allen, Chase A.

    2007-01-01

    Structural equation modeling (SEM) has become increasingly popular in counseling, psychology, and rehabilitation research. The purpose of this article is to provide an overview of the basic concepts and applications of SEM in rehabilitation counseling research using the AMOS statistical software program.

  11. Composite fuselage shell structures research at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Starnes, James H., Jr.; Shuart, Mark J.

    1992-01-01

    Fuselage structures for transport aircraft represent a significant percentage of both the weight and the cost of these aircraft primary structures. Composite materials offer the potential for reducing both the weight and the cost of transport fuselage structures, but only limited studies of the response and failure of composite fuselage structures have been conducted for transport aircraft. The behavior of these important primary structures must be understood, and the structural mechanics methodology for analyzing and designing these complex stiffened shell structures must be validated in the laboratory. The effects of local gradients and discontinuities on fuselage shell behavior and the effects of local damage on pressure containment must be thoroughly understood before composite fuselage structures can be used for commercial aircraft. This paper describes the research being conducted and planned at NASA LaRC to help understand the critical behavior or composite fuselage structures and to validate the structural mechanics methodology being developed for stiffened composite fuselage shell structure subjected to combined internal pressure and mechanical loads. Stiffened shell and curved stiffened panel designs are currently being developed and analyzed, and these designs will be fabricated and then tested at Langley to study critical fuselage shell behavior and to validate structural analysis and design methodology. The research includes studies of the effects of combined internal pressure and mechanical loads on nonlinear stiffened panel and shell behavior, the effects of cutouts and other gradient-producing discontinuities on composite shell response, and the effects of local damage on pressure containment and residual strength. Scaling laws are being developed that relate full-scale and subscale behavior of composite fuselage shells. Failure mechanisms are being identified and advanced designs will be developed based on what is learned from early results from

  12. Heparin's solution structure determined by small-angle neutron scattering.

    PubMed

    Rubinson, Kenneth A; Chen, Yin; Cress, Brady F; Zhang, Fuming; Linhardt, Robert J

    2016-12-01

    Heparin is a linear, anionic polysaccharide that is widely used as a clinical anticoagulant. Despite its discovery 100 years ago in 1916, the solution structure of heparin remains unknown. The solution shape of heparin has not previously been examined in water under a range of concentrations, and here is done so in D2 O solution using small-angle neutron scattering (SANS). Solutions of 10 kDa heparin-in the millimolar concentration range-were probed with SANS. Our results show that when sodium concentrations are equivalent to the polyelectrolyte's charge or up to a few hundred millimoles higher, the molecular structure of heparin is compact and the shape could be well modeled by a cylinder with a length three to four times its diameter. In the presence of molar concentrations of sodium, the molecule becomes extended to nearly its full length estimated from reported X-ray measurements on stretched fibers. This stretched form is not found in the presence of molar concentrations of potassium ions. In this high-potassium environment, the heparin molecules have the same shape as when its charges were mostly protonated at pD ≈ 0.5, that is, they are compact and approximately half the length of the extended molecules.

  13. The Physical Character of Small-Scale Interstellar Structures

    NASA Technical Reports Server (NTRS)

    Lauroesch, James T.

    2005-01-01

    The primary objective of this program was to obtain FUSE observations of the multiple interstellar absorption lines of H2 toward the members of 3 resolvable binary/multiple star systems to explore the physical conditions in known interstellar small-scale structures. Each of the selected systems was meant to address a different aspect of the models for the origin of these structures: 1) The stars HD 32039/40 were meant to probe a temporally varying component which probed a cloud with an inferred size of tens to a few hundreds of AU. The goal was to see if there was any significant H2 associated with this component; 2) The star HD 36408B and its companion HD 36408A (observed as part of FUSE GTO program P119) show significant spatial and temporal (proper motion induced) Na I column variations in a strong, relatively isolated component, as well as a relatively simple component structure. The key goal here was to identify any differences in H2 or C I excitation between the sightlines, and to measure the physical conditions (primarily density and temperature) in the temporally varying component; 3) The stars HD 206267C and HD 206267D are highly reddened sightlines which showed significant variations in K I and molecular absorption lines in multiple velocity components. Coupled with FUSE GTO observations of HD 206267A (program P116), the goal was to study the variations in H2 along sightlines which are significantly more distant, with larger separations, and with greater extinctions than the other selected binary systems.

  14. Detecting small scale CO2 emission structures using OCO-2

    NASA Astrophysics Data System (ADS)

    Schwandner, Florian M.; Eldering, Annmarie; Verhulst, Kristal R.; Miller, Charles E.; Nguyen, Hai M.; Oda, Tomohiro; O'Dell, Christopher; Rao, Preeti; Kahn, Brian; Crisp, David; Gunson, Michael R.; Sanchez, Robert M.; Ashok, Manasa; Pieri, David; Linick, Justin P.; Yuen, Karen

    2016-04-01

    Localized carbon dioxide (CO2) emission structures cover spatial domains of less than 50 km diameter and include cities and transportation networks, as well as fossil fuel production, upgrading and distribution infra-structure. Anthropogenic sources increasingly upset the natural balance between natural carbon sources and sinks. Mitigation of resulting climate change impacts requires management of emissions, and emissions management requires monitoring, reporting and verification. Space-borne measurements provide a unique opportunity to detect, quantify, and analyze small scale and point source emissions on a global scale. NASA's first satellite dedicated to atmospheric CO2 observation, the July 2014 launched Orbiting Carbon Observatory (OCO-2), now leads the afternoon constellation of satellites (A-Train). Its continuous swath of 2 to 10 km in width and eight footprints across can slice through coincident emission plumes and may provide momentary cross sections. First OCO-2 results demonstrate that we can detect localized source signals in the form of urban total column averaged CO2 enhancements of ~2 ppm against suburban and rural backgrounds. OCO-2's multi-sounding swath observing geometry reveals intra-urban spatial structures reflected in XCO2 data, previously unobserved from space. The transition from single-shot GOSAT soundings detecting urban/rural differences (Kort et al., 2012) to hundreds of soundings per OCO-2 swath opens up the path to future capabilities enabling urban tomography of greenhouse gases. For singular point sources like coal fired power plants, we have developed proxy detections of plumes using bands of imaging spectrometers with sensitivity to SO2 in the thermal infrared (ASTER). This approach provides a means to automate plume detection with subsequent matching and mining of OCO-2 data for enhanced detection efficiency and validation. © California Institute of Technology

  15. Small Schools: The Numbers Tell a Story. A Review of the Research and Current Experiences. The Small Schools Workshop.

    ERIC Educational Resources Information Center

    Klonsky, Michael

    A compelling body of research shows that when students are part of smaller and more intimate learning communities, they are more successful. The latest research demonstrates that small schools, particularly schools of choice, have a measurably positive impact on inner-city students, especially those from minority and low-income families. The…

  16. 10 CFR 600.381 - Special provisions for Small Business Innovation Research Grants.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Special provisions for Small Business Innovation Research... Organizations Additional Provisions § 600.381 Special provisions for Small Business Innovation Research Grants. (a) General. This section contains provisions applicable to the Small Business Innovation...

  17. Structural modeling of proteins by integrating small-angle x-ray scattering data

    NASA Astrophysics Data System (ADS)

    Zhang, Yong-Hui; Peng, Jun-Hui; Zhang, Zhi-Yong

    2015-12-01

    Elucidating the structure of large biomolecules such as multi-domain proteins or protein complexes is challenging due to their high flexibility in solution. Recently, an “integrative structural biology” approach has been proposed, which aims to determine the protein structure and characterize protein flexibility by combining complementary high- and low-resolution experimental data using computer simulations. Small-angle x-ray scattering (SAXS) is an efficient technique that can yield low-resolution structural information, including protein size and shape. Here, we review computational methods that integrate SAXS with other experimental datasets for structural modeling. Finally, we provide a case study of determination of the structure of a protein complex formed between the tandem SH3 domains in c-Cb1-associated protein and the proline-rich loop in human vinculin. Project supported by the National Key Basic Research Program of China (Grant Nos. 2013CB910203 and 2011CB911104), the National Natural Science Foundation of China (Grant No. 31270760), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB08030102), and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20113402120013).

  18. TESOL, Teacher Identity, and the Need for "Small Story" Research

    ERIC Educational Resources Information Center

    Vasquez, Camilla

    2011-01-01

    Narrative research in TESOL still remains very much in its infancy. And the predominant mode of narrative research in TESOL--following the trend in educational research, as well as in other social sciences--has clearly been that of narrative inquiry, with its concomitant privileging of autobiographical "big stories", or researcher-elicited…

  19. Small but Powerful: Top Predator Local Extinction Affects Ecosystem Structure and Function in an Intermittent Stream

    PubMed Central

    Rodríguez-Lozano, Pablo; Verkaik, Iraima; Rieradevall, Maria; Prat, Narcís

    2015-01-01

    Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators’ extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1) leads to a ‘mesopredator release’, affects primary consumers and changes whole community structures, and (2) triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel), conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to ‘mesopredator release’, and also to ‘prey release’ despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem’s structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers’ extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been

  20. Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

    PubMed

    Rodríguez-Lozano, Pablo; Verkaik, Iraima; Rieradevall, Maria; Prat, Narcís

    2015-01-01

    Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1) leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2) triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel), conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been extirpated, to restore

  1. Linear feature extraction from radar imagery: SBIR (Small Business Innovative Research), phase 2, option 2

    NASA Astrophysics Data System (ADS)

    Milgram, David L.; Kahn, Philip; Conner, Gary D.; Lawton, Daryl T.

    1988-12-01

    The goal of this effort is to develop and demonstrate prototype processing capabilities for a knowledge-based system to automatically extract and analyze features from Synthetic Aperture Radar (SAR) imagery. This effort constitutes Phase 2 funding through the Defense Small Business Innovative Research (SBIR) Program. Previous work examined the feasibility of and technology issues involved in the development of an automated linear feature extraction system. This final report documents this examination and the technologies involved in automating this image understanding task. In particular, it reports on a major software delivery containing an image processing algorithmic base, a perceptual structures manipulation package, a preliminary hypothesis management framework and an enhanced user interface.

  2. FE analysis strategies for structural materials with small tensile strength

    SciTech Connect

    Borri, A. ); Sorace, S. )

    1993-05-01

    A review of the smeared crack approach to the finite element analysis of small tensile strength (STS) materials is presented. The most widely applied strategies for crack modeling, shear transfer mechanism, and the definition of the mechanical constitutive laws and failure critically discussed. The models and special options in the ANSYS, ADINA, and ABAQUS programs are considered in detail, and applied to the analysis of a square panel under boundary pressures. The three solutions were compared in terms of the final broadening of the panel cracked zones. The results of the analysis of an hemispherical dome over a cylindrical drum are also presented. The Romulus Temple in the Roman Forum was the reference structure for this FE model. The problem was analyzed by a special procedure using the ANSYS concrete element. The results were compared with those of a discrete crack solution which reproduced the real cracked configuration of the building, and then with an experimental survey carried out by the flat jack technique.

  3. Structural network connectivity and cognition in cerebral small vessel disease.

    PubMed

    Tuladhar, Anil M; van Dijk, Ewoud; Zwiers, Marcel P; van Norden, Anouk G W; de Laat, Karlijn F; Shumskaya, Elena; Norris, David G; de Leeuw, Frank-Erik

    2016-01-01

    Cerebral small vessel disease (SVD), including white matter hyperintensities (WMH), lacunes and microbleeds, and brain atrophy, are related to cognitive impairment. However, these magnetic resonance imaging (MRI) markers for SVD do not account for all the clinical variances observed in subjects with SVD. Here, we investigated the relation between conventional MRI markers for SVD, network efficiency and cognitive performance in 436 nondemented elderly with cerebral SVD. We computed a weighted structural connectivity network from the diffusion tensor imaging and deterministic streamlining. We found that SVD-severity (indicated by higher WMH load, number of lacunes and microbleeds, and lower total brain volume) was related to networks with lower density, connection strengths, and network efficiency, and to lower scores on cognitive performance. In multiple regressions models, network efficiency remained significantly associated with cognitive index and psychomotor speed, independent of MRI markers for SVD and mediated the associations between these markers and cognition. This study provides evidence that network (in)efficiency might drive the association between SVD and cognitive performance. This highlights the importance of network analysis in our understanding of SVD-related cognitive impairment in addition to conventional MRI markers for SVD and might provide an useful tool as disease marker.

  4. The Small Aircraft Transportation System (SATS): Research Collaborations with the NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Tarry, Scott E.; Bowen, Brent D.; Nickerson, Jocelyn S.

    2002-01-01

    The aviation industry is an integral part of the world s economy. Travelers have consistently chosen aviation as their mode of transportation as it is reliable, time efficient and safe. The out- dated Hub and Spoke system, coupled with high demand, has led to delays, cancellations and gridlock. NASA is developing innovative solutions to these and other air transportation problems. This research is being conducted through partnerships with federal agencies, industry stakeholders, and academia, specifically the University of Nebraska at Omaha. Each collaborator is pursuing the NASA General Aviation Roadmap through their involvement in the expansion of the Small Aircraft Transportation System (SATS). SATS will utilize technologically advanced small aircraft to transport travelers to and from rural and isolated communities. Additionally, this system will provide a safe alternative to the hub and spoke system, giving more time to more people through high-speed mobility and increased accessibility.

  5. Composite Structures and Materials Research at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Starnes, James H., Jr.; Dexter, H. Benson; Johnston, Norman J.; Ambur, Damodar R.; Cano, Roberto J.

    2001-01-01

    A summary of recent composite structures and materials research at NASA Langley Research Center is presented. Fabrication research to develop low-cost automated robotic fabrication procedures for thermosetting and thermoplastic composite materials, and low-cost liquid molding processes for preformed textile materials is described. Robotic fabrication procedures discussed include ply-by-ply, cure-on-the-fly heated placement head and out-of-autoclave electron-beam cure methods for tow and tape thermosetting and thermoplastic materials. Liquid molding fabrication processes described include Resin Film Infusion (RFI) Resin Transfer Molding (RTM) and Vacuum-Assisted Resin Transfer Molding (VARTM). Results for a full-scale composite wing box are summarized to identify the performance of materials and structures fabricated with these low-cost fabrication methods.

  6. Composite Structures and Materials Research at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Starnes, James H., Jr.; Dexter, H. Benson; Johnston, Norman J.; Ambur, Damodar R.; Cano, roberto J.

    2003-01-01

    A summary of recent composite structures and materials research at NASA Langley Research Center is presented. Fabrication research to develop low-cost automated robotic fabrication procedures for thermosetting and thermoplastic composite materials, and low-cost liquid molding processes for preformed textile materials is described. Robotic fabrication procedures discussed include ply-by-ply, cure-on-the-fly heated placement head and out-of-autoclave electron-beam cure methods for tow and tape thermosetting and thermoplastic materials. Liquid molding fabrication processes described include Resin Film Infusion (RFI), Resin Transfer Molding (RTM) and Vacuum-Assisted Resin Transfer Molding (VARTM). Results for a full-scale composite wing box are summarized to identify the performance of materials and structures fabricated with these low-cost fabrication methods.

  7. Small Business Innovation Research, Program solicitation closing data: March 8, 1993

    SciTech Connect

    Not Available

    1993-01-01

    DOE invites small business firms to submit grant applications under this eleventh annual solicitation for the Small Business Innovation Research (SBIR) program. Firms with strong research capabilities in science or engineering in any of the topic areas described in Appendix I are encouraged to participate. DOE will support high-quality research or research and development (R D) on advanced concepts concerning important energy related scientific or engineering problems and opportunities that could lead to significant public benefit if the research is successful.

  8. Structural formation of huntingtin-like aggregates probed by small-angle neutron scattering

    SciTech Connect

    Stanley, Christopher B; Perevozchikova, Tatiana; Berthelier-Jung, Valerie M

    2011-01-01

    In several neurodegenerative disorders, including Huntington s disease (HD), aspects concerning the earliest of protein structures that form along the aggregation pathway have increasingly gained attention since these particular species are likely to be neurotoxic. We used time-resolved small-angle neutron scattering (SANS) to probe in solution these transient structures formed by peptides having the N-terminal sequence context of mutant huntingtin (Htt) exon 1. We obtained snapshots of the formed aggregates as the kinetic reaction ensued to yield quantitative information on their size and mass. At the early stage, small precursor species with an initial radius of gyration (Rg) of 16.1 5.9 and average mass of a dimer to trimer were monitored. Structural growth was treated as two modes with a transition from three-dimensional early aggregate formation to two-dimensional fibril growth and association. Our SANS results on the internal structure of the mature fibrils demonstrate loose packing with about 1 peptide per 4.75 -sheet repeat distance, which is shown to be quantitatively consistent with a -helix model. This research provides new insights into the structures forming along the pathway of Htt exon 1 aggregation and should assist in determining the role that precursors play in neuronal toxicity.

  9. A Research Brief: Small Learning Communities--Recommendations for Success

    ERIC Educational Resources Information Center

    Urban Education Collaborative, 2010

    2010-01-01

    Over the last 15 years, a variety of efforts to transform American high schools have gained both public and private support. Significant among these efforts are initiatives to implement small learning communities (SLCs). Like other reform efforts, SLCs have several goals, including "downsizing large schools, meeting the needs of at-risk students,…

  10. USEPA'S RESEARCH EFFORTS IN SMALL DRINKING WATER TREATMENT TECHNOLOGIES

    EPA Science Inventory

    Currently, in the United States there are approximately 50,000 small community and 130,000 non-community systems providing water to over 25 million people. The drinking water treatment systems at these locations are not always adequate to comply with current and pending regulati...

  11. Arsenic Removal from Drinking Water Small Systems Research

    EPA Science Inventory

    This Power Point presentation will summarize some of the results from Arsenic Demonstration Program with the main focus on the adsorptive media systems used by small systems. The presentation will also describe the results of recent regeneration studies conducted on the arsenic ...

  12. Investigation of the small-scale structure and dynamics of Uranus' atmosphere

    NASA Technical Reports Server (NTRS)

    Eshleman, Von R.; Hinson, David P.

    1991-01-01

    This document constitutes the final technical report of the Uranus Analysis Program. Papers and/or abstracts resulting from this research are presented. The following topics are covered: (1) past and future of radio occultation studies of planetary atmospheres; (2) equatorial waves in the stratosphere of Uranus; (3) the atmosphere of Uranus- results of radio occultation measurements with Voyager 2; (4) Uranus' atmospheric dynamics and circulation; (5) small-scale structure and dynamics in the atmosphere of Uranus; (6) evidence for inertia-gravity waves in the stratosphere of Uranus derived from Voyager 2 radio occultation data; and (7) planetary waves in the equatorial stratosphere of Uranus.

  13. Effect of Small Changes in Secondary Structure on the Electron Transfer Rate in Proteins

    NASA Astrophysics Data System (ADS)

    Wolfgang, J.; Risser, S. M.

    1996-03-01

    In the non-adiabatic limit, the rate of electron transfer reactions is proportional to the square of the electronic coupling between donor and acceptor. The distance decay of the coupling in a protein is sensitive to the protein geometry and the tunneling energy of the electron. In this paper, we use Green's function methods combined with molecular dynamics simulations to examine how the electronic coupling is modulated by the primary, secondary and tertiary structure of polypeptides. We also will explore the sensitivity of the coupling to small changes in atomic coordinates. This work was supported by the Research Corporation and East Texas State University.

  14. Heterogeneous road networks have no apparent effect on the genetic structure of small mammal populations.

    PubMed

    Grilo, Clara; Del Cerro, Irene; Centeno-Cuadros, Alejandro; Ramiro, Victor; Román, Jacinto; Molina-Vacas, Guillem; Fernández-Aguilar, Xavier; Rodríguez, Juan; Porto-Peter, Flávia; Fonseca, Carlos; Revilla, Eloy; Godoy, José A

    2016-09-15

    Roads are widely recognized to represent a barrier to individual movements and, conversely, verges can act as potential corridors for the dispersal of many small mammals. Both barrier and corridor effects should generate a clear spatial pattern in genetic structure. Nevertheless, the effect of roads on the genetic structure of small mammal populations still remains unclear. In this study, we examine the barrier effect that different road types (4-lane highway, 2-lane roads and single-lane unpaved roads) may have on the population genetic structure of three species differing in relevant life history traits: southern water vole Arvicola sapidus, the Mediterranean pine vole Microtus duodecimcostatus and the Algerian mouse Mus spretus. We also examine the corridor effect of highway verges on the Mediterranean pine vole and the Algerian mouse. We analysed the population structure through pairwise estimates of FST among subpopulations bisected by roads, identified genetic clusters through Bayesian assignment approaches, and used simple and partial Mantel tests to evaluate the relative barrier or corridor effect of roads. No strong evidences were found for an effect of roads on population structure of these three species. The barrier effect of roads seems to be site-specific and no corridor effect of verges was found for the pine vole and Algerian mouse populations. The lack of consistent results among species and for each road type lead us to believe that the ability of individual dispersers to use those crossing structures or the habitat quality in the highway verges may have a relatively higher influence on gene flow among populations than the presence of crossing structures per se. Further research should include microhabitat analysis and the estimates of species abundance to understand the mechanisms that underlie the genetic structure observed at some sites.

  15. The United States Air Force Small Business Innovation Research Program

    DTIC Science & Technology

    1990-01-01

    system. These drills motion, and release of toxic multiple fracturing of the have very low torque and thrust fumes . Blasting is thus limited to...relatively small size of the individual shots, together with the unique spiral blasting pattern, allows the process to be continuous, even in a tunneling...production contracts with a federal’agency for products and processes intended for use by the U.S. Govemment. SBIR companies can include sole

  16. Managing Astronomy Research Data: Case Studies of Big and Small Research Projects

    NASA Astrophysics Data System (ADS)

    Sands, Ashley E.

    2015-01-01

    Astronomy data management refers to all actions taken upon data over the course of the entire research process. It includes activities involving the collection, organization, analysis, release, storage, archiving, preservation, and curation of research data. Astronomers have cultivated data management tools, infrastructures, and local practices to ensure the use and future reuse of their data. However, new sky surveys will soon amass petabytes of data requiring new data management strategies.The goal of this dissertation, to be completed in 2015, is to identify and understand data management practices and the infrastructure and expertise required to support best practices. This will benefit the astronomy community in efforts toward an integrated scholarly communication framework.This dissertation employs qualitative, social science research methods (including interviews, observations, and document analysis) to conduct case studies of data management practices, covering the entire data lifecycle, amongst three populations: Sloan Digital Sky Survey (SDSS) collaboration team members; Individual and small-group users of SDSS data; and Large Synoptic Survey Telescope (LSST) collaboration team members. I have been observing the collection, release, and archiving of data by the SDSS collaboration, the data practices of individuals and small groups using SDSS data in journal articles, and the LSST collaboration's planning and building of infrastructure to produce data.Preliminary results demonstrate that current data management practices in astronomy are complex, situational, and heterogeneous. Astronomers often have different management repertoires for working on sky surveys and for their own data collections, varying their data practices as they move between projects. The multitude of practices complicates coordinated efforts to maintain data.While astronomy expertise proves critical to managing astronomy data in the short, medium, and long term, the larger astronomy

  17. Physics and Chemistry of Small Scale Structures for Modern Devices

    DTIC Science & Technology

    1991-06-01

    that in AIGaAs. In the InAs- ZnTe system, the increase in speed is due to the small dielectric constant in ZaTe and the high mobility in InAs, and the...temperature. In addition, 1 _____0__ ._._... ... the small dielectric constant in ZnTe and the high mobility ---- : T = 3OCK GoAs-ZnSe in InAs should...semiconductors were explored. While the materials to date have not been single crystal but have consisted of relatively small grain polycrystal in vandium

  18. A Small Acoustic Goniometer for General Purpose Research

    PubMed Central

    Pook, Michael L.; Loo, Sin Ming

    2016-01-01

    Understanding acoustic events and monitoring their occurrence is a useful aspect of many research projects. In particular, acoustic goniometry allows researchers to determine the source of an event based solely on the sound it produces. The vast majority of acoustic goniometry research projects used custom hardware targeted to the specific application under test. Unfortunately, due to the wide range of sensing applications, a flexible general purpose hardware/firmware system does not exist for this purpose. This article focuses on the development of such a system which encourages the continued exploration of general purpose hardware/firmware and lowers barriers to research in projects requiring the use of acoustic goniometry. Simulations have been employed to verify system feasibility, and a complete hardware implementation of the acoustic goniometer has been designed and field tested. The results are reported, and suggested areas for improvement and further exploration are discussed. PMID:27136563

  19. A Small Acoustic Goniometer for General Purpose Research.

    PubMed

    Pook, Michael L; Loo, Sin Ming

    2016-04-29

    Understanding acoustic events and monitoring their occurrence is a useful aspect of many research projects. In particular, acoustic goniometry allows researchers to determine the source of an event based solely on the sound it produces. The vast majority of acoustic goniometry research projects used custom hardware targeted to the specific application under test. Unfortunately, due to the wide range of sensing applications, a flexible general purpose hardware/firmware system does not exist for this purpose. This article focuses on the development of such a system which encourages the continued exploration of general purpose hardware/firmware and lowers barriers to research in projects requiring the use of acoustic goniometry. Simulations have been employed to verify system feasibility, and a complete hardware implementation of the acoustic goniometer has been designed and field tested. The results are reported, and suggested areas for improvement and further exploration are discussed.

  20. Research on inflatable structure for space use

    NASA Astrophysics Data System (ADS)

    Katou, Sumio; Muragishi, Osamu; Oota, Toyoyuki; Natori, Michihiro; Miura, Kouryou; Sakamaki, Masamori

    1993-03-01

    This report describes an overview of the trial manufacture and research related to the feasibility of the concepts of a reflector structure using inflatable elements, inflatable tube, and recommendations on experiments on the exposed facility of the JEM (Japanese Experiment Module). The expected roles of and basic structure concept concerning the configurations, dimensions, and film surface materials of the reflector are outlined. The results of the film pressure deformation test, film element hardening test, and film and supporting truss interface test are described. The strength, trial manufacture, and its results are outlined. The onboard JEM experiment concept concerning the research on the earth, preliminary experiment, and on-orbit experiment onboard JEM are introduced.

  1. 10 CFR 600.381 - Special provisions for Small Business Innovation Research Grants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Special provisions for Small Business Innovation Research... Organizations Additional Provisions § 600.381 Special provisions for Small Business Innovation Research Grants... unexpended at the end of the project if those amounts exceed $500; (6) Recipients will certify in writing...

  2. Toward an Alternative Research Paradigm for Small/Rural Schools: Beyond an Approximated Reality.

    ERIC Educational Resources Information Center

    Dobson, Russell L; Dobson, Judith E.

    1990-01-01

    Presents arguments, based on Thomas Kuhn's work, that most research on rural and small schools proceeds from previous scientific achievements, and that researchers' (outsiders') preconceived and approximated reality forces the nature of rural and small schools into an inflexible box. Contains 40 references. (Author/SV)

  3. Research and Applications in Aeroelasticity and Structural Dynamics at the NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Abel, Irving

    1997-01-01

    An overview of recently completed programs in aeroelasticity and structural dynamics research at the NASA Langley Research Center is presented. Methods used to perform flutter clearance studies in the wind-tunnel on a high performance fighter are discussed. Recent advances in the use of smart structures and controls to solve aeroelastic problems, including flutter and gust response are presented. An aeroelastic models program designed to support an advanced high speed civil transport is described. An extension to transonic small disturbance theory that better predicts flows involving separation and reattachment is presented. The results of a research study to determine the effects of flexibility on the taxi and takeoff characteristics of a high speed civil transport are presented. The use of photogrammetric methods aboard Space Shuttle to measure spacecraft dynamic response is discussed. Issues associated with the jitter response of multi-payload spacecraft are discussed. Finally a Space Shuttle flight experiment that studied the control of flexible spacecraft is described.

  4. Structure Optimization and Evaluation of Small Adjustable Diameter Grinding Wheel

    NASA Astrophysics Data System (ADS)

    Yao, Yiyong; Li, Yuanyuan; Zhao, Liping; Zhao, Hu

    Focus on the uneven deformation of conventional adjustable diameter grinding wheel (ADGW), a structure optimization and evaluation method of ADGW was proposed in this paper. Firstly, the evaluation index system and structure optimization framework of ADGW was established to obtain the optimization objective of ADGW. Then a simulated experiment was provided. The flexible units of ADGW with different structures and geometries were selected to analyze the unevenness of deformation. The comparison results showed that the proposed method can improve the ADGW structures effectively and provide a technical approach for evaluating the structure design of ADGW.

  5. Structural and Functional Insights into Small, Glutamine-Rich, Tetratricopeptide Repeat Protein Alpha

    PubMed Central

    Roberts, Joanna D.; Thapaliya, Arjun; Martínez-Lumbreras, Santiago; Krysztofinska, Ewelina M.; Isaacson, Rivka L.

    2015-01-01

    The small glutamine-rich, tetratricopeptide repeat-containing protein alpha (SGTA) is an emerging player in the quality control of secretory and membrane proteins mislocalized to the cytosol, with established roles in tail-anchored (TA) membrane protein biogenesis. SGTA consists of three structural domains with individual functions, an N-terminal dimerization domain that assists protein sorting pathways, a central tetratricopeptide repeat (TPR) domain that mediates interactions with heat-shock proteins, proteasomal, and hormonal receptors, and viral proteins, and a C-terminal glutamine rich region that binds hydrophobic substrates. SGTA has been linked to viral lifecycles and hormone receptor signaling, with implications in the pathogenesis of various disease states. Thus far, a range of biophysical techniques have been employed to characterize SGTA structure in some detail, and to investigate its interactions with binding partners in different biological contexts. A complete description of SGTA structure, together with further investigation into its function as a co-chaperone involved quality control, could provide us with useful insights into its role in maintaining cellular proteostasis, and broaden our understanding of mechanisms underlying associated pathologies. This review describes how some structural features of SGTA have been elucidated, and what this has uncovered about its cellular functions. A brief background on the structure and function of SGTA is given, highlighting its importance to biomedicine and related fields. The current level of knowledge and what remains to be understood about the structure and function of SGTA is summarized, discussing the potential direction of future research. PMID:26734616

  6. Structure of nanocrystalline palladium and copper studied by small angle neutron scattering

    SciTech Connect

    Sanders, P.G.; Weertman, J.R.; Barker, J.G.

    1996-12-01

    The structure of nanocrystalline palladium and copper, made by inert gas condensation and compaction, was studied using small angle neutron scattering (SANS), optical microscopy, and scanning electron microscopy. The effects of annealing and warm compaction were also examined with these techniques. The SANS results were interpreted using a maximum entropy routine, combined with knowledge of the Archimedes density and hydrogen concentration determined by prompt gamma activation analysis (PGAA). Similar hydrogen concentrations were detected by SANS and PGAA. This hydrogen content, which was approximately 5 at.{percent} in samples compacted at room temperature, was reduced by both annealing and warm compaction. Defects in several size classes were observed, including missing grain pores ({approx_equal}1{endash}50 nm diameter) and defects of micrometer size. Warm compaction produced a lower number density of pores in nanocrystalline palladium, which led to increased density. The observed structure was correlated with Vickers microhardness and fracture surface morphology. {copyright} {ital 1996 Materials Research Society.}

  7. Advanced Deployable Shell-Based Composite Booms for Small Satellite Structural Applications Including Solar Sails

    NASA Technical Reports Server (NTRS)

    Fernandez, Juan M.

    2017-01-01

    sail missions for such composite boom systems are already under consideration and development at NASA, as well as mission studies that will benefit from planned scaled-up versions of the composite boom technologies to be introduced. The paper presents ongoing research and development of thin-shell rollable composite booms designed under the particular stringent and challenging system requirements of relatively large solar sails housed on small satellites. These requirements will be derived and listed. Several new boom concepts are proposed and other existing ones are improved upon using thin-ply composite materials to yield unprecedented compact deployable structures. Some of these booms are shown in Fig. 1. For every boom to be introduced the scalable fabrication process developed to keep the overall boom system cost down will be shown. Finally, the initial results of purposely designed boom structural characterization test methods with gravity off-loading will be presented to compare their structural performance under expected and general load cases.

  8. 6. FLYWHEEL FOR THE 32/28 STRUCTURAL MILL. THE SMALL ELECTRIC ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. FLYWHEEL FOR THE 32/28 STRUCTURAL MILL. THE SMALL ELECTRIC MOTOR IN FOREGROUND MAY HAVE BEEN USED TO HELP START THE MILL. - U.S. Steel Homestead Works, Structural Mill, Along Monongahela River, Homestead, Allegheny County, PA

  9. Distributed Acquisition for Geomagnetic Research (DAGR) for SmallSats

    NASA Astrophysics Data System (ADS)

    Zesta, E.; Bonalsky, T. M.; Wendel, D. E.; Simpson, D. G.; Beach, T. L.; Allen, L.; Clavier, O.

    2015-12-01

    Geomagnetic field measurements are a fundamental, key parameter measurement for any space weather application, particularly for tracking the electromagnetic energy input in the Ionosphere-Thermosphere system and for high latitude dynamics governed by the large-scale field-aligned currents. The full characterization of the Magnetosphere-Ionosphere-Thermosphere coupled system necessitates measurements with higher spatial/temporal resolution and from multiple locations simultaneously. This becomes extremely challenging in the current state of shrinking budgets. Traditionally, including a science-grade magnetometer in a mission necessitates very costly integration and design (sensor on long boom) and imposes magnetic cleanliness restrictions on all components of the bus and payload. Recent advances in Smallsat and Cubesat developments offer a pathway for the proliferation of measurements. However, the Cubesat bus is a small volume in which to include all traditional bus components and payload, and the low cost of such programs makes the acquisition of clean Geomagnetic field observations a challenge. This work presents our approach of combining multiple sensitive onboard sensors with an innovative algorithm approach that enables high quality magnetic field measurements in Cubesats.

  10. Measuring forest structure along productivity gradients in the Canadian boreal with small-footprint Lidar.

    PubMed

    Bolton, Douglas K; Coops, Nicholas C; Wulder, Michael A

    2013-08-01

    The structure and productivity of boreal forests are key components of the global carbon cycle and impact the resources and habitats available for species. With this research, we characterized the relationship between measurements of forest structure and satellite-derived estimates of gross primary production (GPP) over the Canadian boreal. We acquired stand level indicators of canopy cover, canopy height, and structural complexity from nearly 25,000 km of small-footprint discrete return Light Detection and Ranging (Lidar) data and compared these attributes to GPP estimates derived from the MODerate resolution Imaging Spectroradiometer (MODIS). While limited in our capacity to control for stand age, we removed recently disturbed and managed forests using information on fire history, roads, and anthropogenic change. We found that MODIS GPP was strongly linked to Lidar-derived canopy cover (r = 0.74, p < 0.01), however was only weakly related to Lidar-derived canopy height and structural complexity as these attributes are largely a function of stand age. A relationship was apparent between MODIS GPP and the maximum sampled heights derived from Lidar as growth rates and resource availability likely limit tree height in the prolonged absence of disturbance. The most structurally complex stands, as measured by the coefficient of variation of Lidar return heights, occurred where MODIS GPP was highest as productive boreal stands are expected to contain a wider range of tree heights and transition to uneven-aged structures faster than less productive stands. While MODIS GPP related near-linearly to Lidar-derived canopy cover, the weaker relationships to Lidar-derived canopy height and structural complexity highlight the importance of stand age in determining the structure of boreal forests. We conclude that an improved quantification of how both productivity and disturbance shape stand structure is needed to better understand the current state of boreal forests in

  11. Smart structures technology and biomechanics research

    NASA Astrophysics Data System (ADS)

    Huston, Dryver R.; Beynnon, Bruce; Krag, Martin

    1996-05-01

    The human musculoskeletal system represents one of the ultimate manifestations of smart structures capabilities. It can sense, actuate, and heal for periods occasionally in excess of one hundred years. As a natural consequence, research and treatment regimes for a variety of musculoskeletal disorders use technologies that are in many respects very similar to that of the more traditional aerospace and civil smart structures technologies. This paper presents an overview of the technologies that are currently in use in orthopaedic practice and research that mimic these more traditional smart structures. This includes a wide variety of instrumentation that can measure loads and motions within the musculoskeletal system, within prostheses (artificial joints and limbs), and within orthoses (devices that limit the motion of joints and limbs). Included are discussions about the instrumentation of spine and hip implants and the use of telemetry to transmit the data, the measurement of spinal motions through goniometers and surface-attached lordosimeters, and the forces involved in ambulation. In addition to the systems that can measure loads and motions, there are some devices that can measure these quantities and respond in such as way as to control the motions or loads. A 'virtual corset' that provides audio and/or tactile feedback to patients to prevent excessive trunk flexion is described.

  12. The Structure and Climate of Size: Small Scale Schooling in an Urban District

    ERIC Educational Resources Information Center

    LeChasseur, Kimberly

    2009-01-01

    This study explores mechanisms involved in small scale schooling and student engagement. Specifically, this study questions the validity of arguments for small scale schooling reforms that confound the promised effects of small scale schooling "structures" (such as smaller enrollments, schools-within-schools, and smaller class sizes)…

  13. Inntags: small self-structured epitopes for innocuous protein tagging.

    PubMed

    Georgieva, Maya V; Yahya, Galal; Codó, Laia; Ortiz, Raúl; Teixidó, Laura; Claros, José; Jara, Ricardo; Jara, Mònica; Iborra, Antoni; Gelpí, Josep Lluís; Gallego, Carme; Orozco, Modesto; Aldea, Martí

    2015-10-01

    Protein tagging is widely used in approaches ranging from affinity purification to fluorescence-based detection in live cells. However, an intrinsic limitation of tagging is that the native function of the protein may be compromised or even abolished by the presence of the tag. Here we describe and characterize a set of small, innocuous protein tags (inntags) that we anticipate will find application in a variety of biological techniques.

  14. Structure and dynamics of small van der Waals complexes

    SciTech Connect

    Loreau, J.

    2014-10-06

    We illustrate computational aspects of the calculation of the potential energy surfaces of small (up to five atoms) van der Waals complexes with high-level quantum chemistry techniques such as the CCSD(T) method with extended basis sets. We discuss the compromise between the required accuracy and the computational time. Further, we show how these potential energy surfaces can be fitted and used in dynamical calculations such as non-reactive inelastic scattering.

  15. Big issues, small systems: managing with information in medical research.

    PubMed

    Jones, J; Preston, H

    2000-08-01

    This subject of this article is the design of a database system for handling files related to the work of the Molecular Genetics Department of the International Blood Group Reference Laboratory. It examines specialist information needs identified within this organization and it indicates how the design of the Rhesus Information Tracking System was able to meet current needs. Rapid Applications Development prototyping forms the basis of the investigation, linked to interview, questionnaire, and observation techniques in order to establish requirements for interoperability. In particular, the place of this specialist database within the much broader information strategy of the National Blood Service will be examined. This unique situation is analogous to management activities in broader environments and a number of generic issues are highlighted by the research.

  16. Ethical Guidelines for Structural Interventions to Small-Scale Historic Stone Masonry Buildings.

    PubMed

    Hurol, Yonca; Yüceer, Hülya; Başarır, Hacer

    2015-12-01

    Structural interventions to historic stone masonry buildings require that both structural and heritage values be considered simultaneously. The absence of one of these value systems in implementation can be regarded as an unethical professional action. The research objective of this article is to prepare a guideline for ensuring ethical structural interventions to small-scale stone historic masonry buildings in the conservation areas of Northern Cyprus. The methodology covers an analysis of internationally accepted conservation documents and national laws related to the conservation of historic buildings, an analysis of building codes, especially Turkish building codes, which have been used in Northern Cyprus, and an analysis of the structural interventions introduced to a significant historic building in a semi-intact state in the walled city of Famagusta. This guideline covers issues related to whether buildings are intact or ruined, the presence of earthquake risk, the types of structural decisions in an architectural conservation project, and the values to consider during the decision making phase.

  17. Current and Future Perspectives on the Structural Identification of Small Molecules in Biological Systems

    PubMed Central

    Dias, Daniel A.; Jones, Oliver A.H.; Beale, David J.; Boughton, Berin A.; Benheim, Devin; Kouremenos, Konstantinos A.; Wolfender, Jean-Luc; Wishart, David S.

    2016-01-01

    Although significant advances have been made in recent years, the structural elucidation of small molecules continues to remain a challenging issue for metabolite profiling. Many metabolomic studies feature unknown compounds; sometimes even in the list of features identified as “statistically significant” in the study. Such metabolic “dark matter” means that much of the potential information collected by metabolomics studies is lost. Accurate structure elucidation allows researchers to identify these compounds. This in turn, facilitates downstream metabolite pathway analysis, and a better understanding of the underlying biology of the system under investigation. This review covers a range of methods for the structural elucidation of individual compounds, including those based on gas and liquid chromatography hyphenated to mass spectrometry, single and multi-dimensional nuclear magnetic resonance spectroscopy, and high-resolution mass spectrometry and includes discussion of data standardization. Future perspectives in structure elucidation are also discussed; with a focus on the potential development of instruments and techniques, in both nuclear magnetic resonance spectroscopy and mass spectrometry that, may help solve some of the current issues that are hampering the complete identification of metabolite structure and function. PMID:27983674

  18. Structural and electronic properties of small silicon clusters

    NASA Astrophysics Data System (ADS)

    Baturin, V. S.; Lepeshkin, S. V.; Magnitskaya, M. V.; Matsko, N. L.; Uspenskii, Yu A.

    2014-05-01

    The atomic structure and electronic spectrum of silicon nanoclusters (Si-ncs) Si7, Si10,Si10H16 and Si10H20 are calculated using the evolutionary algorithm with total energy computed within density functional theory and generalized gradient approximation (DFT-GGA). When analysing the low-energy structures, we pay significant attention to their symmetry and interatomic bond geometry. The candidate structures arising in the process of evolutionary algorithm convergence are also considered and classified by their topology and grouping near local energy minima. Possible ways to improve the convergence of evolutionary computation are discussed. Addressing qualitative criteria for the ground-state atomic structure of Si-ncs, we consider correlations between the density of electronic states and the total energetics of clusters in the ground state and low-energy-isomer configurations.

  19. Small Business Innovation Research, Program solicitation closing data: March 8, 1993

    SciTech Connect

    Not Available

    1993-01-01

    DOE invites small business firms to submit grant applications under this eleventh annual solicitation for the Small Business Innovation Research (SBIR) program. Firms with strong research capabilities in science or engineering in any of the topic areas described in Appendix I are encouraged to participate. DOE will support high-quality research or research and development (R&D) on advanced concepts concerning important energy related scientific or engineering problems and opportunities that could lead to significant public benefit if the research is successful.

  20. Introduction to Journal of Structural Geology special issue on "Deformation of the lithosphere. How small structures tell a big story"

    NASA Astrophysics Data System (ADS)

    Sintubin, Manuel; de Bresser, Hans; Drury, Martyn; Prior, David J.; Wenk, Hans-Rudolf

    2015-02-01

    This special issue Deformation of the Lithosphere. How small structures tell a big story is dedicated to Professor Henk Zwart (1924-2012). The theme is inspired by Henk's retirement lecture entitled Mountains must indeed be studied with a microscope (19 February 1988). Henk Zwart was a pioneer in linking microstructural research with the large-scale issues concerning lithospheric rheology and deformation. The famous Zwart's Hen House, representing the nine diagnostic relationships of porphyroblast growth with respect to the timing of deformation, is still a key element in contemporary textbooks on structural geology and microtectonics. This particular insight may not have occurred if it wasn't for a mistake made by the thin-section maker in the Leiden lab of Henk Zwart. By accident a thin section of a Pyrenean metamorphic rock was made, not perpendicular to the lineation - as was the standard procedure in those early days of structural geology - but parallel to the lineation. That mistake and Henk's recognition that the lineation parallel view gave more useful information changed structural geology and microtectonics.

  1. Science Education Research vs. Physics Education Research: A Structural Comparison

    ERIC Educational Resources Information Center

    Akarsu, Bayram

    2010-01-01

    The main goal of this article is to introduce physics education research (PER) to researchers in other fields. Topics include discussion of differences between science education research (SER) and physics education research (PER), physics educators, research design and methodology in physics education research and current research traditions and…

  2. Managing Change in Small Scottish Primary Schools. SCRE Research Report Series.

    ERIC Educational Resources Information Center

    Wilson, Valerie; McPake, Joanna

    This report describes Scottish research on ways in which headteachers in small primary schools managed mandated changes. The research focused on implementation of four recent major initiatives: 5-14 Curriculum Guidelines, School Development Planning, Staff Development and Appraisal, and Devolved School Management. Research methods included a…

  3. Community-oriented support and research structures

    NASA Astrophysics Data System (ADS)

    Attig, Norbert; Eickermann, Thomas; Gibbon, Paul; Lippert, Thomas

    2009-07-01

    Coordinated by the Partnership for Advanced Computing in Europe (PRACE) Europe is restructuring and strengthening its high-performance computing infrastructure with the aim to create a model HPC ecosystem. At the tip of the pyramid, up to six centres are envisaged that will operate systems of the highest performance class. The HPC Research Infrastructure (HPC-RI) will comprise European, national and regional centres. Science communities are integral partners, strong links will include Grid and Cloud users. The HPC-RI strives at providing scientists all over Europe, on the one hand, with unlimited and independent access to state-of-the-art computer resources in all performance classes and, on the other hand, with a world-class pan-European competence and support network. While the hardware-oriented buildup of the infrastructure is making progress, high-quality user support and software development in the upcoming era of unprecedented parallelism and exascale on the horizon have become the imminent challenges. This has been clearly recognized by the European Commission, who will issue calls for proposals to fund petascale software development in summer 2009. Although traditional support structures are well established in Europe's major supercomputing centres, it is questionable if these structures are able to meet the challenges of the future: in general, support structures are based on cross-disciplinary computer science and mathematics teams; disciplinary computational science support usually is given in an ad-hoc, project-oriented manner. In this paper, we describe our approach to establish a suitable support structure-Simulation Laboratories (SL). SLs are currently being established at the Jülich Supercomputing Centre of the Forschungszentrum Jülich (FZJ) and at the Steinbuch Centre for Computing (SCC) of the Karlsruhe Institute for Technology (KIT) in Germany. While SLs are community-oriented, i.e. each SL focusses on a specific community, they are structured

  4. Formation of structure in small lead clusters under thermal effect

    NASA Astrophysics Data System (ADS)

    Baidyshev, V. S.; Gafner, Yu. Ya.

    2016-12-01

    The thermal effect on lead clusters with radii up to 5.5 nm has been investigated by the molecular dynamics method using a modified tight-binding potential TB-SMA. The melting of Pb nanoparticles of these sizes is strictly homogeneous, without the formation of a surface liquidlike layer. The primary fcc phase in the particles is retained upon heating in the overwhelming majority of model experiments. An analysis of the structure formation during crystallization has shown that structures with pentagonal symmetry are preferred for lead clusters in this case. It is noted that an increase in the nanoparticle size leads to the dominance of the dodecahedral structure over the icosahedral one.

  5. The Small-Scale Structure of Acceleration in Wall Turbulence

    NASA Astrophysics Data System (ADS)

    Christensen, Kenneth T.; Adrian, Ronald J.

    2001-11-01

    Temporal and convective derivatives of velocity are measured in the streamwise--wall-normal plane of turbulent channel flow at Re_τ=547, 1133, and 1734 using a new technique called particle-image accelerometry. Pairs of temporally-resolved instantaneous velocity fields are acquired in rapid succession using a two-CCD-camera arrangement, and the associated instantaneous temporal and convective derivatives of velocity are computed numerically from this data. Advection of the small-scale vortices embedded within the flow dominates the small-scale behavior of the velocity time-derivative as noted in both the instantaneous rate-of-change fields as well as in the statistics of the temporal derivative. However, in a reference frame traveling with the vortices, a marked deceleration is present and represents the evolution of the flow. This large-scale deceleration is conjectured to be the dynamic influence of larger-scale vortices present further away from the wall on the smaller scale vortices present closer to the wall.

  6. Funding and Strategic Alignment Guidance for Infusing Small Business Innovation Research Technology into Aeronautics Research Mission Directorate Projects for 2016

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.; Steele, Gynelle C.

    2017-01-01

    This report is intended to help NASA program and project managers incorporate Small Business Innovation Research (SBIR) technologies into NASA Aeronautics Research Mission Directorate (ARMD) projects. Other Government and commercial project managers interested in ARMD funding opportunities through NASA's SBIR program will find this report useful as well.

  7. Small Sample Research Designs for Evidence-based Rehabilitation: Issues and Methods

    PubMed Central

    Graham, James E.; Karmarkar, Amol M.; Ottenbacher, Kenneth J.

    2012-01-01

    Conventional research methods, including randomized controlled trials, are powerful techniques for determining the efficacy of interventions. These designs, however, have practical limitations when applied to many rehabilitation settings and research questions. Alternative methods are available that can supplement findings from traditional research designs and improve our ability to evaluate the effectiveness of treatments for individual patients. The focus on individual patients is an important element of evidenced-based rehabilitation. This paper examines one such alternate approach: small-N research designs. Small-N designs usually focus on ten or fewer participants whose behavior (outcomes) are measured repeatedly and compared over time. The advantages and limitations of various small-N designs are described and illustrated using three examples from the rehabilitation literature. The challenges and opportunities of applying small-N designs to enhance evidence-based rehabilitation are discussed. PMID:22580169

  8. Small sample research designs for evidence-based rehabilitation: issues and methods.

    PubMed

    Graham, James E; Karmarkar, Amol M; Ottenbacher, Kenneth J

    2012-08-01

    Conventional research methods, including randomized controlled trials, are powerful techniques for determining the efficacy of interventions. These designs, however, have practical limitations when applied to many rehabilitation settings and research questions. Alternative methods are available that can supplement findings from traditional research designs and improve our ability to evaluate the effectiveness of treatments for individual patients. The focus on individual patients is an important element of evidenced-based rehabilitation. This article examines one such alternate approach: small-N research designs. Small-N designs usually focus on 10 or fewer participants whose behavior (outcomes) are measured repeatedly and compared over time. The advantages and limitations of various small-N designs are described and illustrated using 3 examples from the rehabilitation literature. The challenges and opportunities of applying small-N designs to enhance evidence-based rehabilitation are discussed.

  9. Pre-clinical research in small animals using radiotherapy technology--a bidirectional translational approach.

    PubMed

    Tillner, Falk; Thute, Prasad; Bütof, Rebecca; Krause, Mechthild; Enghardt, Wolfgang

    2014-12-01

    For translational cancer research, pre-clinical in-vivo studies using small animals have become indispensable in bridging the gap between in-vitro cell experiments and clinical implementation. When setting up such small animal experiments, various biological, technical and methodical aspects have to be considered. In this work we present a comprehensive topical review based on relevant publications on irradiation techniques used for pre-clinical cancer research in mice and rats. Clinical radiotherapy treatment devices for the application of external beam radiotherapy and brachytherapy as well as dedicated research irradiation devices are feasible for small animal irradiation depending on the animal model and the experimental goals. In this work, appropriate solutions for the technological transfer of human radiation oncology to small animal radiation research are summarised. Additionally, important information concerning the experimental design is provided such that reliable and clinically relevant results can be attained.

  10. Cross--Cultural Small Group Research: A Review, an Analysis, and a Theory

    ERIC Educational Resources Information Center

    Shuter, Robert

    1977-01-01

    Reviews and analyzes research on cross-national small group behavior and offers a value theory of small group development. Available from: International Journal of Intercultural Relations, Transaction Periodicals Consortium, Rutgers-The State University, New Brunswick, New Jersey 08903. (MH)

  11. 48 CFR 227.7104 - Contracts under the Small Business Innovation Research (SBIR) Program.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... PATENTS, DATA, AND COPYRIGHTS Rights in Technical Data 227.7104 Contracts under the Small Business... Data and Computer Software—Small Business Innovation Research (SBIR) Program, when technical data or... clause at 252.227-7018, the Government obtains SBIR data rights in technical data and computer...

  12. Small Business Innovation Research Award Success Story: FuelCell Energy Inc.

    SciTech Connect

    2011-08-31

    This success story describes FuelCell Energy Inc., a small business that manufactures stationary fuel cells. In collaboration with Sustainable Innovations LLC, and with support from a Small Business Innovation Research (SBIR) Award from the U.S. Department of Energy's Fuel Cell Technologies Program, FuelCell Energy Inc. has developed a highly efficient solid state electrochemical hydrogen compressor.

  13. 77 FR 47797 - Federal Acquisition Regulation; Small Business Set Asides for Research and Development Contracts

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-10

    ... aside acquisitions for research and development, when there is also a reasonable expectation, as a... expectation of obtaining from small businesses the best scientific and technological sources consistent with...)(3), to clarify that for R&D small business set-asides, there must be a reasonable expectation...

  14. A Review of Research on Small-School Student Participation in Extracurricular Activities.

    ERIC Educational Resources Information Center

    Stevens, Neil G.; Peltier, Gary L.

    1994-01-01

    Research reveals that high school students in small schools participate more in extracurricular activities than their peers in large schools; that a high degree of student participation provides opportunities for enhancing leadership, responsibility, and motivation; that students in small schools feel needed; and that the benefits of…

  15. Performance optimized, small structurally integrated ion thruster system

    NASA Technical Reports Server (NTRS)

    Hyman, J., Jr.

    1973-01-01

    A 5-cm structurally integrated ion thruster has been developed for attitude control and stationkeeping of synchronous satellites. As optimized with a conventional ion extraction system, the system demonstrates a thrust T = 0.47 mlb at a beam voltage of 1600 V, total mass efficiency of 76%, and electrical efficiency of 56%. Under the subject contract effort, no significant performance change was noted for operation with two dimensional electrostatic thrust-vectoring grids. Structural integrity with the vectoring grids was demonstrated for shock (+ or - 30 G), sinusoidal (9 G), and random (19.9 G rms) accelerations. System envelope is 31.2 cm long by 13.4 cm flange bolt circle, with a mass of 9.0 Kg, including 6.8 Kg mercury propellant.

  16. Dynamics and structural changes of small water clusters on ionization.

    PubMed

    Lee, Han Myoung; Kim, Kwang S

    2013-07-05

    Despite utmost importance in understanding water ionization process, reliable theoretical results of structural changes and molecular dynamics (MD) of water clusters on ionization have hardly been reported yet. Here, we investigate the water cations [(H2O)(n = 2-6)(+)] with density functional theory (DFT), Möller-Plesset second-order perturbation theory (MP2), and coupled cluster theory with single, double, and perturbative triple excitations [CCSD(T)]. The complete basis set limits of interaction energies at the CCSD(T) level are reported, and the geometrical structures, electronic properties, and infrared spectra are investigated. The characteristics of structures and spectra of the water cluster cations reflect the formation of the hydronium cation moiety (H3O(+)) and the hydroxyl radical. Although most density functionals fail to predict reasonable energetics of the water cations, some functionals are found to be reliable, in reasonable agreement with high-level ab initio results. To understand the ionization process of water clusters, DFT- and MP2-based Born-Oppenheimer MD (BOMD) simulations are performed on ionization. On ionization, the water clusters tend to have an Eigen-like form with the hydronium cation instead of a Zundel-like form, based on reliable BOMD simulations. For the vertically ionized water hexamer, the relatively stable (H2O)5(+) (5sL4A) cluster tends to form with a detached water molecule (H2O).

  17. Aeroservoelastic and Structural Dynamics Research on Smart Structures Conducted at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    McGowan, Anna-Maria Rivas; Wilkie, W. Keats; Moses, Robert W.; Lake, Renee C.; Florance, Jennifer Pinkerton; Wieseman, Carol D.; Reaves, Mercedes C.; Taleghani, Barmac K.; Mirick, Paul H.; Wilbur, Matthew L.

    1998-01-01

    An overview of smart structures research currently underway at the NASA Langley Research Center in the areas of aeroservoelasticity and structural dynamics is presented. Analytical and experimental results, plans, potential technology pay-offs, and challenges are discussed. The goal of this research is to develop the enabling technologies to actively and passively control aircraft and rotorcraft vibration and loads using smart devices. These enabling technologies and related research efforts include developing experimentally-validated finite element and aeroservoelastic modeling techniques; conducting bench experimental tests to assess feasibility and understand system trade-offs; and conducting large-scale wind- tunnel tests to demonstrate system performance. The key aeroservoelastic applications of this research include: active twist control of rotor blades using interdigitated electrode piezoelectric composites and active control of flutter, and gust and buffeting responses using discrete piezoelectric patches. In addition, NASA Langley is an active participant in the DARPA/ Air Force Research Laboratory/ NASA/ Northrop Grumman Smart Wing program which is assessing aerodynamic performance benefits using smart materials. Keywords: aeroelasticity, smart structures, piezoelectric actuators, active fiber composites, rotorcraft, buffet load alleviation, individual blade control, aeroservoelasticity, shape memory alloys, damping augmentation, piezoelectric power consumption

  18. Analytical challenges of determining composition and structure in small volumes with applications to semiconductor technology, nanostructures and solid state science

    NASA Astrophysics Data System (ADS)

    Ma, Zhiyong; Kuhn, Markus; Johnson, David C.

    2017-03-01

    Determining the structure and composition of small volumes is vital to the ability to understand and control nanoscale properties and critical for advancing both fundamental science and applications, such as semiconductor device manufacturing. While metrology of nanoscale materials (nanoparticles, nanocomposites) and nanoscale semiconductor structures is challenging, both basic research and cutting edge technology benefit from new and enhanced analytical techniques. This focus issue contains articles describing approaches to overcome the challenges in obtaining statistically significant atomic-scale quantification of structure and composition in a variety of materials and devices using electron microscopy and atom probe tomography.

  19. Theoretical studies of the electronic structure of small metal clusters

    NASA Technical Reports Server (NTRS)

    Jordan, K. D.

    1982-01-01

    Theoretical studies of the electronic structure of metal clusters, in particular clusters of Group IIA and IIB atoms were conducted. Early in the project it became clear that electron correlation involving d orbitals plays a more important role in the binding of these clusters than had been previously anticipated. This necessitated that computer codes for calculating two electron integrals and for constructing the resulting CI Hamiltonions be replaced with newer, more efficient procedures. Program modification, interfacing and testing were performed. Results of both plans are reported.

  20. Ordered structures of small numbers of nanorods induced by semiflexible star polymers.

    PubMed

    Zhang, Dong; He, Lilin; Zhang, Linxi

    2014-09-14

    The ordered structures of nanorods (NRs) in the semiflexible star polymer/NR mixtures are explored by employing molecular dynamics simulation. The structures of small numbers of NRs can be well controlled by varying the stiffness of semiflexible star polymers. At a moderate binding energy between star polymers and NRs, four completely different structures of small numbers of NRs are observed, including that the side-to-side hexagonal aggregation structures of NRs for flexible star polymers, the partly parallel aggregation structures of NRs and the end-to-end contact parallel aggregation structures of NRs for semiflexible star polymers, and the partial dispersion of NRs for rigid star polymers. Helical conformations of semiflexible star polymers binding with NRs are responsible for the formation of the end-to-end contact parallel aggregation structures for small numbers of NRs. This investigation may provide a possible pathway to develop ''smart'' medium to construct novel materials with high performance.

  1. The use of small-molecule structures to complement protein–ligand crystal structures in drug discovery

    PubMed Central

    Cole, Jason C.

    2017-01-01

    Many ligand-discovery stories tell of the use of structures of protein–ligand complexes, but the contribution of structural chemistry is such a core part of finding and improving ligands that it is often overlooked. More than 800 000 crystal structures are available to the community through the Cambridge Structural Database (CSD). Individually, these structures can be of tremendous value and the collection of crystal structures is even more helpful. This article provides examples of how small-molecule crystal structures have been used to complement those of protein–ligand complexes to address challenges ranging from affinity, selectivity and bioavailability though to solubility. PMID:28291759

  2. Extraction of Vegetation Biophysical Structure from Small-Footprint Full-Waveform Lidar Signals

    NASA Astrophysics Data System (ADS)

    Romanczyk, Paul

    The National Ecological Observatory Network (NEON) is a continental scale environmental monitoring initiative tasked with characterizing and understanding ecological phenomenology over a 30-year time frame. To support this mission, NEON collects ground truth measurements, such as organism counts and characterization, carbon flux measurements, etc. To spatially upscale these plot-based measurements, NEON developed an airborne observation platform (AOP), with a high-resolution visible camera, next-generation AVIRIS imaging spectrometer, and a discrete and waveform digitizing light detection and ranging (lidar) system. While visible imaging, imaging spectroscopy, and discrete lidar are relatively mature technologies, our understanding of and associated algorithm development for small-footprint full-waveform lidar are still in early stages of development. This work has as its primary aim to extend small-footprint full-waveform lidar capabilities to assess vegetation biophysical structure. In order to fully exploit waveform lidar capabilities, high fidelity geometric and radio-metric truth data are needed. Forests are structurally and spectrally complex, which makes collecting the necessary truth challenging, if not impossible. We utilize the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model, which provides an environment for radiometric simulations, in order to simulate waveform lidar signals. The first step of this research was to build a virtual forest stand based on Harvard Forest inventory data. This scene was used to assess the level of geometric fidelity necessary for small-footprint waveform lidar simulation in broadleaf forests. It was found that leaves have the largest influence on the backscattered signal and that there is little contribution to the signal from the leaf stems and twigs. From this knowledge, a number of additional realistic and abstract virtual "forest" scenes were created to aid studies assessing the ability of waveform lidar

  3. Longitudinal Structure Function F L of Proton from Regge Like Behaviour of Structure Function at Small-x

    NASA Astrophysics Data System (ADS)

    Baruah, Nomita; Das, Mrinal Kumar; Sarma, Jayanta Kumar

    2014-08-01

    The evolutions of longitudinal structure function F L from quantum chromodynamics (QCD) evolution equation in next-to-leading order at small-x is presented using the Regge like behaviour of the structure function. The proposed simple analytical expression for F L structure function provides the t- and x-evolution equations to study the behaviour of F L structure function at small-x. The calculated results are compared with the data of H1, ZEUS collaborations and results of Block model, Donnachie-Landshoff model. Our calculated results can be described within the framework of perturbative QCD.

  4. Aeroservoelastic and Structural Dynamics Research on Smart Structures Conducted at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    McGowan, Anna-Maria Rivas; Wilkie, W. Keats; Moses, Robert W.; Lake, Renee C.; Florance, Jennifer Pinkerton; Wieseman, Carol D.; Reaves, Mercedes C.; Taleghani, Barmac K.; Mirick, Paul H.; Wilbur, Mathew L.

    1997-01-01

    An overview of smart structures research currently underway at the NASA Langley Research Center in the areas of aeroservoelasticity and structural dynamics is presented. Analytical and experimental results, plans, potential technology pay-offs, and challenges are discussed. The goal of this research is to develop the enabling technologies to actively and passively control aircraft and rotorcraft vibration and loads using smart devices. These enabling technologies and related research efforts include developing experimentally-validated finite element and aeroservoelastic modeling techniques; conducting bench experimental tests to assess feasibility and understand system trade-offs; and conducting large-scale wind tunnel tests to demonstrate system performance. The key aeroservoelastic applications of this research include: active twist control of rotor blades using interdigitated electrode piezoelectric composites and active control of flutter, and gust and buffeting responses using discrete piezoelectric patches. In addition, NASA Langley is an active participant in the DARPA/Air Force Research Laboratory/NASA/Northrop Grumman Smart Wing program which is assessing aerodynamic performance benefits using smart materials.

  5. Perceptions of the UK's Research Excellence Framework 2014: A Small Survey of Academics

    ERIC Educational Resources Information Center

    Murphy, Tony; Sage, Daniel

    2015-01-01

    Earlier work inspired by a body of literature raised important questions about the workings of the UK's Research Excellence Framework (REF) and its predecessor the Research Assessment Framework (RAE), and noted the possible adverse outcomes of such processes. This paper builds on this by examining the findings of a small survey of social science…

  6. "It's Really Making a Difference": How Small-Scale Research Projects Can Enhance Teaching and Learning

    ERIC Educational Resources Information Center

    Dexter, Barbara; Seden, Roy

    2012-01-01

    Following an internal evaluation exercise, using Action Research, this paper identifies the positive impact of small-scale research projects on teaching and learning at a single case study UK University. Clear evidence is given of how the projects benefited students and staff, and enhanced institutional culture. Barriers to better practice are…

  7. Towards systematic planning of small-scale hydrological intervention-based research

    NASA Astrophysics Data System (ADS)

    Pramana, Kharis Erasta Reza; Ertsen, Maurits Willem

    2016-10-01

    Many small-scale water development initiatives are accompanied by hydrological research to study either the form of the intervention or its impacts. Humans influence both the development of intervention and research, and thus one needs to take human agency into account. This paper focuses on the effects of human actions in the development of the intervention and its associated hydrological research, as hydrological research is often designed without adequate consideration of how to account for human agency and that these effects have not yet been discussed explicitly in a systematic way. In this paper, we propose a systematic planning for hydrological research, based on evaluating three hydrological research efforts targeting small-scale water development initiatives in Vietnam, Kenya, and Indonesia. The main purpose of the three cases was to understand the functioning of interventions in their hydrological contexts. Aiming for better decision-making on hydrological research in small-scale water intervention initiatives, we propose two analysis steps, including (1) consideration of possible surprises and possible actions and (2) cost-benefit analysis. By performing the two analyses continuously throughout small-scale hydrological intervention-based initiatives, effective hydrological research can be achieved.

  8. Insights into the channel gating of P2X receptors from structures, dynamics and small molecules

    PubMed Central

    Wang, Jin; Yu, Ye

    2016-01-01

    P2X receptors, as ATP-gated non-selective trimeric ion channels, are permeable to Na+, K+ and Ca2+. Comparing with other ligand-gated ion channel families, P2X receptors are distinct in their unique gating properties and pathophysiological roles, and have attracted attention as promising drug targets for a variety of diseases, such as neuropathic pain, multiple sclerosis, rheumatoid arthritis and thrombus. Several small molecule inhibitors for distinct P2X subtypes have entered into clinical trials. However, many questions regarding the gating mechanism of P2X remain unsolved. The structural determinations of P2X receptors at the resting and ATP-bound open states revealed that P2X receptor gating is a cooperative allosteric process involving multiple domains, which marks the beginning of the post-structure era of P2X research at atomic level. Here, we review the current knowledge on the structure-function relationship of P2X receptors, depict the whole picture of allosteric changes during the channel gating, and summarize the active sites that may contribute to new strategies for developing novel allosteric drugs targeting P2X receptors. PMID:26725734

  9. Mechanism Research on Melting Loss of Coppery Tuyere Small Sleeve in Blast Furnace

    NASA Astrophysics Data System (ADS)

    Chai, Yi-Fan; Zhang, Jian-Liang; Ning, Xiao-Jun; Wei, Guang-Yun; Chen, Yu-Ting

    2016-01-01

    The tuyere small sleeve in blast furnace works under poor conditions. The abnormal damage of it will severely affect the performance of the blast furnace, thus it should be replaced during the damping down period. So it is of great significance that we study and reduce the burnout of tuyere small sleeve. Melting loss is one case of its burnout. This paper studied the reasons of tuyere small sleeve's melting loss, through computational simulation and microscopic analysis of the melting section. The research shows that the temperature of coppery tuyere small sleeve is well distributed when there is no limescale in the lumen, and the temperature increases with the thickness of limescale. In addition, the interruption of circulating water does great harm to the tuyere small sleeve. The melting loss of tuyere small sleeve is caused by iron-slag erosion, with the occurrence of the melt metallurgical bonding and diffusion metallurgical combination.

  10. NASA Lewis Research Center/university graduate research program on engine structures

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1985-01-01

    NASA Lewis Research Center established a graduate research program in support of the Engine Structures Research activities. This graduate research program focuses mainly on structural and dynamics analyses, computational mechanics, mechanics of composites and structural optimization. The broad objectives of the program, the specific program, the participating universities and the program status are briefly described.

  11. NASA Lewis Research Center/University Graduate Research Program on Engine Structures

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1985-01-01

    NASA Lewis Research Center established a graduate research program in support of the Engine Structures Research activities. This graduate research program focuses mainly on structural and dynamics analyses, computational mechanics, mechanics of composites and structural optimization. The broad objectives of the program, the specific program, the participating universities and the program status are briefly described.

  12. Small

    SciTech Connect

    Montoya, Joseph

    2013-07-18

    Representing the Center on Nanostructuring for Efficient Energy Conversion (CNEEC), this document is one of the entries in the Ten Hundred and One Word Challenge. As part of the challenge, the 46 Energy Frontier Research Centers were invited to represent their science in images, cartoons, photos, words and original paintings, but any descriptions or words could only use the 1000 most commonly used words in the English language, with the addition of one word important to each of the EFRCs and the mission of DOE energy. The mission of CNEEC is to understand how nanostructuring can enhance efficiency for energy conversion and solve fundamental cross-cutting problems in advanced energy conversion and storage systems.

  13. Structural Biology and Molecular Applications Research

    Cancer.gov

    Part of NCI's Division of Cancer Biology's research portfolio, research and development in this area focuses on enabling technologies, models, and methodologies to support basic and applied cancer research.

  14. Small-angle X-ray scattering: a bridge between RNA secondary structures and three-dimensional topological structures.

    PubMed

    Fang, Xianyang; Stagno, Jason R; Bhandari, Yuba R; Zuo, Xiaobing; Wang, Yun-Xing

    2015-02-01

    Whereas the structures of small to medium-sized well folded RNA molecules often can be determined by either X-ray crystallography or NMR spectroscopy, obtaining structural information for large RNAs using experimental, computational, or combined approaches remains a major interest and challenge. RNA is very sensitive to small-angle X-ray scattering (SAXS) due to high electron density along phosphate-sugar backbones, whose scattering contribution dominates SAXS intensity. For this reason, SAXS is particularly useful in obtaining global RNA structural information that outlines backbone topologies and, therefore, molecular envelopes. Such information is extremely valuable in bridging the gap between the secondary structures and three-dimensional topological structures of RNA molecules, particularly those that have proven difficult to study using other structure-determination methods. Here we review published results of RNA topological structures derived from SAXS data or in combination with other experimental data, as well as details on RNA sample preparation for SAXS experiments.

  15. PSRna: Prediction of small RNA secondary structures based on reverse complementary folding method.

    PubMed

    Li, Jin; Xu, Chengzhen; Wang, Lei; Liang, Hong; Feng, Weixing; Cai, Zhongxi; Wang, Ying; Cong, Wang; Liu, Yunlong

    2016-08-01

    Prediction of RNA secondary structures is an important problem in computational biology and bioinformatics, since RNA secondary structures are fundamental for functional analysis of RNA molecules. However, small RNA secondary structures are scarce and few algorithms have been specifically designed for predicting the secondary structures of small RNAs. Here we propose an algorithm named "PSRna" for predicting small-RNA secondary structures using reverse complementary folding and characteristic hairpin loops of small RNAs. Unlike traditional algorithms that usually generate multi-branch loops and 5[Formula: see text] end self-folding, PSRna first estimated the maximum number of base pairs of RNA secondary structures based on the dynamic programming algorithm and a path matrix is constructed at the same time. Second, the backtracking paths are extracted from the path matrix based on backtracking algorithm, and each backtracking path represents a secondary structure. To improve accuracy, the predicted RNA secondary structures are filtered based on their free energy, where only the secondary structure with the minimum free energy was identified as the candidate secondary structure. Our experiments on real data show that the proposed algorithm is superior to two popular methods, RNAfold and RNAstructure, in terms of sensitivity, specificity and Matthews correlation coefficient (MCC).

  16. Small-angle X-ray scattering: a bridge between RNA secondary structures and three-dimensional topological structures

    SciTech Connect

    Fang, Xianyang; Stagno, Jason R.; Bhandari, Yuba R.; Zuo, Xiaobing; Wang, Yun-Xing

    2015-02-01

    Whereas the structures of small to medium-sized well folded RNA molecules often can be determined by either X-ray crystallography or NMR spectroscopy, obtaining structural information for large RNAs using experimental, computational, or combined approaches remains a major interest and challenge. RNA is very sensitive to small-angle X-ray scattering (SAXS) due to high electron density along phosphate-sugar backbones, whose scattering contribution dominates SAXS intensity. For this reason, SAXS is particularly useful in obtaining global RNA structural information that outlines backbone topologies and, therefore, molecular envelopes. Such information is extremely valuable in bridging the gap between the secondary structures and three-dimensional topological structures of RNAmolecules, particularly those that have proven difficult to study using other structuredetermination methods. Here we review published results of RNA topological structures derived from SAXS data or in combination with other experimental data, as well as details on RNA sample preparation for SAXS experiments.

  17. Analysis of small scale turbulent structures and the effect of spatial scales on gas transfer

    NASA Astrophysics Data System (ADS)

    Schnieders, Jana; Garbe, Christoph

    2014-05-01

    The exchange of gases through the air-sea interface strongly depends on environmental conditions such as wind stress and waves which in turn generate near surface turbulence. Near surface turbulence is a main driver of surface divergence which has been shown to cause highly variable transfer rates on relatively small spatial scales. Due to the cool skin of the ocean, heat can be used as a tracer to detect areas of surface convergence and thus gather information about size and intensity of a turbulent process. We use infrared imagery to visualize near surface aqueous turbulence and determine the impact of turbulent scales on exchange rates. Through the high temporal and spatial resolution of these types of measurements spatial scales as well as surface dynamics can be captured. The surface heat pattern is formed by distinct structures on two scales - small-scale short lived structures termed fish scales and larger scale cold streaks that are consistent with the footprints of Langmuir Circulations. There are two key characteristics of the observed surface heat patterns: 1. The surface heat patterns show characteristic features of scales. 2. The structure of these patterns change with increasing wind stress and surface conditions. In [2] turbulent cell sizes have been shown to systematically decrease with increasing wind speed until a saturation at u* = 0.7 cm/s is reached. Results suggest a saturation in the tangential stress. Similar behaviour has been observed by [1] for gas transfer measurements at higher wind speeds. In this contribution a new model to estimate the heat flux is applied which is based on the measured turbulent cell size und surface velocities. This approach allows the direct comparison of the net effect on heat flux of eddies of different sizes and a comparison to gas transfer measurements. Linking transport models with thermographic measurements, transfer velocities can be computed. In this contribution, we will quantify the effect of small scale

  18. Research in Electromagnetic Shielding Theory. Part 2. EMP (electromagnetic Pulse) Simulation Using Small Loops

    DTIC Science & Technology

    1988-03-01

    Electromagnetic Shielding Theory: Part 2. EMP Simulation Using Small Loops by Richard L. Monroe D TIC ELECTESP 19 19880 Prepared by D Sol Telecommunications...1197 EEETN. N112 N 17 TiTLE, (’nc~ude SecL~rir) C;assifica ton) 4 Research in Electromagnetic Shielding Theory: Part 2. EIP Simulation Using Small...r.ýeceisary and identify by block number) F;ELD GROUP SUB-GROUP E:1 ,ýelac-trornagnetic pulse); electromagnetic shielding

  19. Funding and Strategic Alignment Guidance for Infusing Small Business Innovation Research Technology Into Aeronautics Research Mission Directorate Projects at NASA Glenn Research Center for 2015

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.; Steele, Gynelle C.; Morris, Jessica R.

    2015-01-01

    This document is intended to enable the more effective transition of NASA Glenn Research Center (GRC) SBIR technologies funded by the Small Business Innovation Research (SBIR) program as well as its companion, the Small Business Technology Transfer (STTR) program into NASA Aeronautics Research Mission Directorate (ARMD) projects. Primarily, it is intended to help NASA program and project managers find useful technologies that have undergone extensive research and development (RRD), through Phase II of the SBIR program; however, it can also assist non-NASA agencies and commercial companies in this process. aviation safety, unmanned aircraft, ground and flight test technique, low emissions, quiet performance, rotorcraft

  20. The structural diversity and promise of antiparasitic marine invertebrate-derived small molecules

    PubMed Central

    Watts, Katharine R; Tenney, Karen; Crews, Phillip

    2010-01-01

    This review focuses on six important parasitic diseases that adversely affect the health and lives of over one billion people worldwide. In light of the global human impact of these neglected tropical diseases (NTDs), several initiatives and campaigns have been mounted to eradicate these infections once and for all. Currently available therapeutics summarized herein are either ineffective and/or have severe and deleterious side effects. Resistant strains continue to emerge and there is an overall unmet and urgent need for new antiparasitic drugs. Marine-derived small molecules (MDSMs) from invertebrates comprise an extremely diverse and promising source of compounds from a wide variety of structural classes. New discoveries of marine natural product privileged structures and compound classes that are being made via natural product library screening using whole cell in vitro assays are highlighted. It is striking to note that for the first time in history the entire genomes of all six parasites have been sequenced and additional transcriptome and proteomic analyses are available. Furthermore, open and shared, publicly available databases of the genome sequences, compounds, screening assays, and druggable molecular targets are being used by the worldwide research community. A combined assessment of all of the above factors, especially of current discoveries in marine natural products, implies a brighter future with more effective, affordable, and benign antiparasitic therapeutics. PMID:20956079

  1. Structural Parameters of Seven Small Magellanic Cloud Intermediate-Age and Old Star Clusters

    NASA Astrophysics Data System (ADS)

    Glatt, Katharina; Grebel, Eva K.; Gallagher, John S., III; Nota, Antonella; Sabbi, Elena; Sirianni, Marco; Clementini, Gisella; Da Costa, Gary; Tosi, Monica; Harbeck, Daniel; Koch, Andreas; Kayser, Andrea

    2009-11-01

    We present structural parameters for the seven intermediate-age and old star clusters NGC 121, Lindsay 1, Kron 3, NGC 339, NGC 416, Lindsay 38, and NGC 419 in the Small Magellanic Cloud (SMC). We fit King profiles and Elson, Fall, and Freeman profiles to both surface-brightness and star-count data taken with the Advanced Camera for Surveys aboard the Hubble Space Telescope. Clusters older than ~1 Gyr show a spread in cluster core radii that increases with age, while the youngest clusters have relatively compact cores. No evidence for post-core-collapse clusters was found. We find no correlation between core radius and distance from the SMC center, although consistent with other studies of dwarf galaxies, some relatively old and massive clusters have low densities. The oldest SMC star cluster, the only globular NGC121, is the most elliptical object of the studied clusters. No correlation is seen between ellipticity and distance from the SMC center. The structures of these massive intermediate-age (1-8 Gyr) SMC star clusters thus appear to primarily result from internal evolutionary processes. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with program GO-10396.

  2. The structural diversity and promise of antiparasitic marine invertebrate-derived small molecules.

    PubMed

    Watts, Katharine R; Tenney, Karen; Crews, Phillip

    2010-12-01

    This review focuses on six important parasitic diseases that adversely affect the health and lives of over one billion people worldwide. In light of the global human impact of these neglected tropical diseases (NTDs), several initiatives and campaigns have been mounted to eradicate these infections once and for all. Currently available therapeutics summarized herein are either ineffective and/or have severe and deleterious side effects. Resistant strains continue to emerge and there is an overall unmet and urgent need for new antiparasitic drugs. Marine-derived small molecules (MDSMs) from invertebrates comprise an extremely diverse and promising source of compounds from a wide variety of structural classes. New discoveries of marine natural product privileged structures and compound classes that are being made via natural product library screening using whole cell in vitro assays are highlighted. It is striking to note that for the first time in history the entire genomes of all six parasites have been sequenced and additional transcriptome and proteomic analyses are available. Furthermore, open and shared, publicly available databases of the genome sequences, compounds, screening assays, and druggable molecular targets are being used by the worldwide research community. A combined assessment of all of the above factors, especially of current discoveries in marine natural products, implies a brighter future with more effective, affordable, and benign antiparasitic therapeutics.

  3. Research in structures, structural dynamics and materials, 1989

    NASA Technical Reports Server (NTRS)

    Hunter, William F. (Compiler); Noor, Ahmed K. (Compiler)

    1989-01-01

    Topics addressed include: composite plates; buckling predictions; missile launch tube modeling; structural/control systems design; optimization of nonlinear R/C frames; error analysis for semi-analytic displacement; crack acoustic emission; and structural dynamics.

  4. Structuring Research Opportunities for All Biology Majors.

    ERIC Educational Resources Information Center

    Lewis, Susan E.; Conley, Lisa K.; Horst, Cynthia J.

    2003-01-01

    Describes a required research experience program for all biology majors instituted in the biology department of Carroll College. Discusses successes and challenges of coordinating a program that involves 20-40 research projects each year. (Author/NB)

  5. NASA Small Business Innovation Research Program. Composite List of Projects, 1983 to 1989

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The NASA SBIR Composite List of Projects, 1983 to 1989, includes all projects that have been selected for support by the Small Business Innovation Research (SBIR) Program of NASA. The list describes 1232 Phase 1 and 510 Phase 2 contracts that had been awarded or were in negotiation for award in August 1990. The main body is organized alphabetically by name of the small businesses. Four indexes cross-reference the list. The objective of this listing is to provide information about the SBIR program to anyone concerned with NASA research and development activities.

  6. Research in Structures and Dynamics, 1984

    NASA Technical Reports Server (NTRS)

    Hayduk, R. J. (Compiler); Noor, A. K. (Compiler)

    1984-01-01

    A symposium on advanced and trends in structures and dynamics was held to communicate new insights into physical behavior and to identify trends in the solution procedures for structures and dynamics problems. Pertinent areas of concern were (1) multiprocessors, parallel computation, and database management systems, (2) advances in finite element technology, (3) interactive computing and optimization, (4) mechanics of materials, (5) structural stability, (6) dynamic response of structures, and (7) advanced computer applications.

  7. Membrane Structure Studies by Means of Small-Angle Neutron Scattering (SANS)

    SciTech Connect

    Knott, R. B.

    2008-03-17

    The basic model for membrane structure--a lipid bilayer with imbedded proteins--was formulated 35 years ago, however the detailed structure is still under active investigation using a variety of physical, chemical and computational techniques. Every biologically active cell is encapsulated by a plasma membrane with most cells also equipped with an extensive intracellular membrane system. The plasma membrane is an important boundary between the cytoplasm of the cell and the external environment, and selectively isolates the cell from that environment. Passive diffusion and/or active transport mechanisms are provided for water, ions, substrates etc. which are vital for cell metabolism and viability. Membranes also facilitate excretion of substances either as useful cellular products or as waste. Despite their complexity and diverse function, plasma membranes from quite different cells have surprisingly similar compositions. A typical membrane structure consists of a phospholipid bilayer with a number of proteins scattered throughout, along with carbohydrates (glycoproteins), glycolipids and sterols. The plasma membranes of most eukaryotic cells contain approximately equal weights of lipid and protein, which corresponds to about 100 lipid molecules per protein molecule. Clearly, lipids are a major constituent and the study of their structure and function in isolation provides valuable insight into the more complex intact multicomponent membrane. The membrane bound protein is the other major constituent and is a very active area of research for a number of reasons including the fact that over 60% of modern drugs act on their receptor sites. The interaction between the protein and the supporting lipid bilayer is clearly of major importance. Neutron scattering is a powerful technique for exploring the structure of membranes, either as reconstituted membranes formed from well characterised lipids, or as intact membranes isolated from selected biological systems. A brief

  8. Bias in Research Grant Evaluation Has Dire Consequences for Small Universities

    PubMed Central

    Murray, Dennis L.; Morris, Douglas; Lavoie, Claude; Leavitt, Peter R.; MacIsaac, Hugh; Masson, Michael E. J.; Villard, Marc-Andre

    2016-01-01

    Federal funding for basic scientific research is the cornerstone of societal progress, economy, health and well-being. There is a direct relationship between financial investment in science and a nation’s scientific discoveries, making it a priority for governments to distribute public funding appropriately in support of the best science. However, research grant proposal success rate and funding level can be skewed toward certain groups of applicants, and such skew may be driven by systemic bias arising during grant proposal evaluation and scoring. Policies to best redress this problem are not well established. Here, we show that funding success and grant amounts for applications to Canada’s Natural Sciences and Engineering Research Council (NSERC) Discovery Grant program (2011–2014) are consistently lower for applicants from small institutions. This pattern persists across applicant experience levels, is consistent among three criteria used to score grant proposals, and therefore is interpreted as representing systemic bias targeting applicants from small institutions. When current funding success rates are projected forward, forecasts reveal that future science funding at small schools in Canada will decline precipitously in the next decade, if skews are left uncorrected. We show that a recently-adopted pilot program to bolster success by lowering standards for select applicants from small institutions will not erase funding skew, nor will several other post-evaluation corrective measures. Rather, to support objective and robust review of grant applications, it is necessary for research councils to address evaluation skew directly, by adopting procedures such as blind review of research proposals and bibliometric assessment of performance. Such measures will be important in restoring confidence in the objectivity and fairness of science funding decisions. Likewise, small institutions can improve their research success by more strongly supporting productive

  9. Bias in Research Grant Evaluation Has Dire Consequences for Small Universities.

    PubMed

    Murray, Dennis L; Morris, Douglas; Lavoie, Claude; Leavitt, Peter R; MacIsaac, Hugh; Masson, Michael E J; Villard, Marc-Andre

    2016-01-01

    Federal funding for basic scientific research is the cornerstone of societal progress, economy, health and well-being. There is a direct relationship between financial investment in science and a nation's scientific discoveries, making it a priority for governments to distribute public funding appropriately in support of the best science. However, research grant proposal success rate and funding level can be skewed toward certain groups of applicants, and such skew may be driven by systemic bias arising during grant proposal evaluation and scoring. Policies to best redress this problem are not well established. Here, we show that funding success and grant amounts for applications to Canada's Natural Sciences and Engineering Research Council (NSERC) Discovery Grant program (2011-2014) are consistently lower for applicants from small institutions. This pattern persists across applicant experience levels, is consistent among three criteria used to score grant proposals, and therefore is interpreted as representing systemic bias targeting applicants from small institutions. When current funding success rates are projected forward, forecasts reveal that future science funding at small schools in Canada will decline precipitously in the next decade, if skews are left uncorrected. We show that a recently-adopted pilot program to bolster success by lowering standards for select applicants from small institutions will not erase funding skew, nor will several other post-evaluation corrective measures. Rather, to support objective and robust review of grant applications, it is necessary for research councils to address evaluation skew directly, by adopting procedures such as blind review of research proposals and bibliometric assessment of performance. Such measures will be important in restoring confidence in the objectivity and fairness of science funding decisions. Likewise, small institutions can improve their research success by more strongly supporting productive

  10. Small business innovation research program solicitation: Closing date July 16, 1990

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This is the eighth annual solicitation by NASA addressed to small business firms, inviting them to submit proposals for research, or research and development, activities in some of the science and engineering areas of interest to NASA. The solicitation describes the Small Business Innovative Research (SBIR) program, identifies eligibility requirements, outlines the required proposal format and content, states proposal preparation and submission requirements, describes the proposal evaluation and award selection process, and provides other information to assist those interested in participating in NASA's SBIR program. It also identifies the technical topics and subtopics for which SBIR proposals are solicited. These cover a broad range of current NASA interests, but do not necessarily include all areas in which NASA plans or currently conducts research. High-risk high pay-off innovations are desired.

  11. Investigation of current university research concerning energy conversion and conservation in small single-family dwellings

    NASA Technical Reports Server (NTRS)

    Grossman, G. R.; Roberts, A. S., Jr.

    1975-01-01

    An investigation was made of university research concerning energy conversion and conservation techniques which may be applied in small single-family residences. Information was accumulated through published papers, progress reports, telephone conversations, and personal interviews. A synopsis of each pertinent investigation is given. Finally, a discussion of the synopses is presented and recommendations are made concerning the applicability of concepts for the design and construction of NASA-Langley Research Center's proposed Technology Utilization House in Hampton, Virginia.

  12. Computational structural mechanics methods research using an evolving framework

    NASA Technical Reports Server (NTRS)

    Knight, N. F., Jr.; Lotts, C. G.; Gillian, R. E.

    1990-01-01

    Advanced structural analysis and computational methods that exploit high-performance computers are being developed in a computational structural mechanics research activity sponsored by the NASA Langley Research Center. These new methods are developed in an evolving framework and applied to representative complex structural analysis problems from the aerospace industry. An overview of the methods development environment is presented, and methods research areas are described. Selected application studies are also summarized.

  13. A Statistical Test of the Relationship between Galactic HI Structure and Small-scale Structure in the Cosmic Microwave Background

    NASA Astrophysics Data System (ADS)

    Verschuur, Gerrit L.

    2014-06-01

    The archive of IRIS, PLANCK and WMAP data available at the IRSA website of IPAC allows the apparent associations between galactic neutral hydrogen (HI) features and small-scale structure in WMAP and PLANCK data to be closely examined. In addition, HI new observations made with the Green Bank Telescope are used to perform a statistical test of putative associations. It is concluded that attention should be paid to the possibility that some of the small-scale structure found in WMAP and PLANCK data harbors the signature of a previously unrecognized source of high-frequency continuum emission in the Galaxy.

  14. 48 CFR 252.227-7018 - Rights in noncommercial technical data and computer software-Small Business Innovation Research...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... technical data and computer software-Small Business Innovation Research (SBIR) Program. 252.227-7018 Section... Clauses 252.227-7018 Rights in noncommercial technical data and computer software—Small Business... Noncommercial Technical Data and Computer Software—Small Business Innovation Research (SBIR) Program (JUN...

  15. 48 CFR 252.227-7018 - Rights in noncommercial technical data and computer software-Small Business Innovation Research...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... technical data and computer software-Small Business Innovation Research (SBIR) Program. 252.227-7018 Section... Clauses 252.227-7018 Rights in noncommercial technical data and computer software—Small Business... Noncommercial Technical Data and Computer Software—Small Business Innovation Research (SBIR) Program (MAR...

  16. 48 CFR 252.227-7018 - Rights in noncommercial technical data and computer software-Small Business Innovation Research...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... technical data and computer software-Small Business Innovation Research (SBIR) Program. 252.227-7018 Section... Clauses 252.227-7018 Rights in noncommercial technical data and computer software—Small Business... Noncommercial Technical Data and Computer Software—Small Business Innovation Research (SBIR) Program (MAY...

  17. 48 CFR 252.227-7018 - Rights in noncommercial technical data and computer software-Small Business Innovation Research...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... technical data and computer software-Small Business Innovation Research (SBIR) Program. 252.227-7018 Section... Clauses 252.227-7018 Rights in noncommercial technical data and computer software—Small Business... Noncommercial Technical Data and Computer Software—Small Business Innovation Research (SBIR) Program (MAR...

  18. Using more than 801 296 small-molecule crystal structures to aid in protein structure refinement and analysis

    PubMed Central

    Cole, Jason C.

    2017-01-01

    The Cambridge Structural Database (CSD) is the worldwide resource for the dissemination of all published three-dimensional structures of small-molecule organic and metal–organic compounds. This paper briefly describes how this collection of crystal structures can be used en masse in the context of macromolecular crystallography. Examples highlight how the CSD and associated software aid protein–ligand complex validation, and show how the CSD could be further used in the generation of geometrical restraints for protein structure refinement. PMID:28291758

  19. Defense Small Business Innovation Research Program (SBIR) Abstracts of Phase I Awards 1984.

    DTIC Science & Technology

    1985-04-16

    DISPLACING AGENT CAN BE RECOVERED AND REUSED BY MEANS OF A COLD TRAP. INDUSTRIAL QUALITY, INC. NAVY $ 49,9900 9832 CANAL ROAD, P. 0. BOX 2397 GAITHERSBURG, MD...APPROACH IS BASED UPON PROVEN TECHNOLOGY FOR TREATMENT OF HUMAN WASTE, DOMESTIC GREYWATER SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM - PHASE I

  20. Employers' Attitudes on Hiring Workers with Intellectual Disabilities in Small and Medium Enterprises: An Italian Research

    ERIC Educational Resources Information Center

    Zappella, Emanuela

    2015-01-01

    Employers play a significant role in the process of hiring workers with intellectual disability. Through an in-depth interview, this research aims to investigate the attitudes of 30 representatives of small and medium-sized Italian companies involved in a process of recruitment. The data were analyzed using a phenomenological approach. The results…

  1. 48 CFR 227.7104 - Contracts under the Small Business Innovation Research (SBIR) Program.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Contracts under the Small Business Innovation Research (SBIR) Program. 227.7104 Section 227.7104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL CONTRACTING...

  2. 48 CFR 227.7104 - Contracts under the Small Business Innovation Research (SBIR) Program.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Contracts under the Small Business Innovation Research (SBIR) Program. 227.7104 Section 227.7104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL CONTRACTING...

  3. 48 CFR 227.7104 - Contracts under the Small Business Innovation Research (SBIR) Program.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Contracts under the Small Business Innovation Research (SBIR) Program. 227.7104 Section 227.7104 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE GENERAL CONTRACTING...

  4. Can We Find Solutions with People? Participatory Action Research with Small Organic Producers in Andalusia

    ERIC Educational Resources Information Center

    Cuellar-Padilla, Mamen; Calle-Collado, Angel

    2011-01-01

    This paper reports on an experiment linking science with people. Taking as a paradigm the holistic scientific approach fostered by agroecology, we present a methodological proposal for the implementation of participatory action research in rural areas. Our aims were various: to solve a specific problem, i.e. the exclusion of small- and…

  5. 48 CFR 227.7104 - Contracts under the Small Business Innovation Research (SBIR) Program.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Data and Computer Software—Small Business Innovation Research (SBIR) Program, when technical data or computer software will be generated during performance of contracts under the SBIR program. (b) Under the clause at 252.227-7018, the Government obtains a royalty-free license to use technical data marked...

  6. Cooperative Learning Strategies for Teaching Small Group Communication: Research and Application.

    ERIC Educational Resources Information Center

    McDougall, Kay; Gimple, Debbie

    Research has shown that cooperative learning rather than competitive behavior enhances students' achievement, self-esteem, and satisfaction while reducing performance anxiety. Although cooperation within a small group results in greater productivity and member satisfaction, it should be considered only as a means to an end, not an end in itself. A…

  7. Structure-based DNA-targeting strategies with small molecule ligands for drug discovery.

    PubMed

    Sheng, Jia; Gan, Jianhua; Huang, Zhen

    2013-09-01

    Nucleic acids are the molecular targets of many clinical anticancer drugs. However, compared with proteins, nucleic acids have traditionally attracted much less attention as drug targets in structure-based drug design, partially because limited structural information of nucleic acids complexed with potential drugs is available. Over the past several years, enormous progresses in nucleic acid crystallization, heavy-atom derivatization, phasing, and structural biology have been made. Many complicated nucleic acid structures have been determined, providing new insights into the molecular functions and interactions of nucleic acids, especially DNAs complexed with small molecule ligands. Thus, opportunities have been created to further discover nucleic acid-targeting drugs for disease treatments. This review focuses on the structure studies of DNAs complexed with small molecule ligands for discovering lead compounds, drug candidates, and/or therapeutics.

  8. Structure-Based DNA-Targeting Strategies with Small Molecule Ligands for Drug Discovery

    PubMed Central

    Sheng, Jia; Gan, Jianhua; Huang, Zhen

    2014-01-01

    Nucleic acids are the molecular targets of many clinical anticancer drugs. However, compared with proteins, nucleic acids have traditionally attracted much less attention as drug targets in structure-based drug design, partially because limited structural information of nucleic acids complexed with potential drugs is available. Over the past several years, enormous progresses in nucleic acid crystallization, heavy-atom derivatization, phasing, and structural biology have been made. Many complicated nucleic acid structures have been determined, providing new insights into the molecular functions and interactions of nucleic acids, especially DNAs complexed with small molecule ligands. Thus, opportunities have been created to further discover nucleic acid-targeting drugs for disease treatments. This review focuses on the structure studies of DNAs complexed with small molecule ligands for discovering lead compounds, drug candidates, and/or therapeutics. PMID:23633219

  9. Amylopectin small chain glucans form structure fingerprint that determines botanical origin of starch.

    PubMed

    Jaiswal, Sarita; Chibbar, Ravindra N

    2017-02-20

    Starch granule size, shape and structure of amylopectin are species specific and influence starch properties and end-use of starch. Amylopectin glucan chain structure was used to predict the starch botanical sources. Mathematical probability for accumulation of small glucan chains DP 6-10 reveal exponential fit curve with maximum R(2) in smallest granule size starches (Chlamydomonas, quinoa, buckwheat). Cereal and cassava showed R(2) of 0.81-0.96 while in pulses and tubers it was less than 0.7. The amylopectin small glucan chains form a unique 'finger print region' that identified starch botanical source. Differential amylopectin chain length distribution (APCLD) graphs between DP 6-80 of all species from Chlamydomonas starch distinguished five structural groups that clustered the 31 analyzed starches into four major patterns. APCLD analyses of amylopectin combined with characteristic pattern of small linear DP (6-9) glucan chains predicted the starch botanical source.

  10. The Helter-Skelter Relationship Between Teaching and Research: A Cluster of Problems and Small Wins.

    ERIC Educational Resources Information Center

    Baker, Paul J.

    1986-01-01

    Contrasts the culture and social structure of research and teaching; demonstrating significant differences in these two spheres of academic work. Explores the question of how scholarship related to teaching can be fostered in a fashion similar to research and identifies six strategies for making gains in this endeavor. (JDH)

  11. Pressure Myography to Study the Function and Structure of Isolated Small Arteries.

    PubMed

    Schjørring, Olav L; Carlsson, Rune; Simonsen, Ulf

    2015-01-01

    Small arteries play an important role in regulation of peripheral resistance and organ perfusion. Here we describe a series of methods allowing measurements in pressurized segments of small arteries from the systemic and coronary circulation of mice as well as other species. The pressure myography techniques described include measurements of wall structure, wall stress, strain, and myogenic tone. The pressurized perfused small arteries also allow evaluation of responses to increases in pressure, flow, and drugs, where the main readout is changes in vascular diameter.

  12. The small-world organization of large-scale brain systems and relationships with subcortical structures.

    PubMed

    Koziol, Leonard F; Barker, Lauren A; Joyce, Arthur W; Hrin, Skip

    2014-01-01

    Brain structure and function is characterized by large-scale brain systems. However, each system has its own "small-world" organization, with sub-regions, or "hubs," that have varying degrees of specialization for certain cognitive and behavioral processes. This article describes this small-world organization, and the concepts of functional specialization and functional integration are defined and explained through practical examples. We also describe the development of large-scale brain systems and this small-world organization as a sensitive, protracted process, vulnerable to a variety of influences that generate neurodevelopmental disorders.

  13. Structural and functional assessment of skin nerve fibres in small-fibre pathology.

    PubMed

    Karlsson, P; Nyengaard, J R; Polydefkis, M; Jensen, T S

    2015-09-01

    Damage to nociceptor nerve fibres may give rise to peripheral neuropathies, some of which are pain free and some are painful. A hallmark of many peripheral neuropathies is the loss of small nerve fibres in the epidermis, a condition called small-fibre neuropathy (SFN) when it is predominantly the small nerve fibres that are damaged. Historically, SFN has been very difficult to diagnose as clinical examination and nerve conduction studies mainly detect large nerve fibres, and quantitative sensory testing is not sensitive enough to detect small changes in small nerve fibres. However, taking a 3-mm punch skin biopsy from the distal leg and quantification of the nerve fibre density has proven to be a useful method to diagnose SFN. However, the correlation between the nerve fibre loss and other test results varies greatly. Recent studies have shown that it is possible not only to extract information about the nerve fibre density from the biopsies but also to get an estimation of the nerve fibre length density using stereology, quantify sweat gland innervation and detect morphological changes such as axonal swelling, all of which may be additional parameters indicating diseased small fibres relating to symptoms reported by the patients. In this review, we focus on available tests to assess structure and function of the small nerve fibres, and summarize recent advances that have provided new possibilities to more specifically relate structural findings with symptoms and function in patients with SFN.

  14. Small-Scale Heterogeneity in Deep-Sea Nematode Communities around Biogenic Structures

    PubMed Central

    Hasemann, Christiane; Soltwedel, Thomas

    2011-01-01

    The unexpected high species richness of deep-sea sediments gives rise to the questions, which processes produce and maintain diversity in the deep sea, and at what spatial scales do these processes operate? The idea of a small-scale habitat structure at the deep-sea floor provides the background for this study. At small scales biogenic structures create a heterogeneous environment that influences the structure of the surrounding communities and the dynamics of the meiobenthic populations. As an example for biogenic structures, small deep-sea sponges (Tentorium semisuberites Schmidt 1870) and their sedimentary environment were investigated for small-scale distribution patterns of benthic deep-sea nematodes. Sampling was carried out with the remotely operated vehicle Victor 6000 at the Arctic deep-sea observatory HAUSGARTEN. In order to investigate nematode community patterns sediment cores around three small sponges and corresponding control cores were analysed. A total of approx. 5800 nematodes were identified. The comparison of the nematode communities from sponge and control samples indicated an influence of the biogenic structure “sponge” on diversity patterns and habitat heterogeneity. The increased number of nematode species and functional groups found in the sediments around the sponges suggest that on a small scale the sponge acts as a gradient and creates a more divers habitat structure. The nematode community from the sponge sediments shows a greater taxonomic variance and species richness together with lower relative abundances of the species compared to those from control sediments. Obviously, the more homogeneous habitat conditions of the control sediments offer less micro-habitats than the sediments around the sponges. This seems to reduce the number of functional groups and species coexisting in the control sediments. PMID:22216193

  15. Assessing Regional Scale Fluxes of Mass, Momentum, and Energy with Small Environmental Research Aircraft

    NASA Astrophysics Data System (ADS)

    Zulueta, Rommel Callejo

    Natural ecosystems are rarely structurally or functionally homogeneous. This is true for the complex coastal regions of Magdalena Bay, Baja California Sur, Mexico, and the Barrow Peninsula on the Arctic Coastal Plain of Alaska. The coastal region of Magdalena Bay is comprised of the Pacific coastal ocean, eutrophic lagoon, mangroves, and desert ecosystems all adjacent and within a few kilometers, while the Barrow Peninsula is a mosaic of small ponds, thaw lakes, different aged vegetated thaw-lake basins ( VDTLBs ) and interstitial tundra which have been dynamically formed by both short- and long-term processes. We used a combination of tower- and small environmental research aircraft (SERA)-based eddy covariance measurements to characterize the spatial and temporal patterns of CO2, latent, and sensible heat fluxes along with MODIS NDVI, and land surface information, to scale the SERA-based CO2 fluxes up to the regional scale. In the first part of this research, the spatial variability in ecosystem fluxes from the Pacific coastal ocean, eutrophic lagoon, mangroves, and desert areas of northern Magdalena Bay were studied. SERA-derived average midday CO2 fluxes from the desert showed a slight uptake of -1.32 mumol CO2 m-2 s-1, the coastal ocean also showed uptake of -3.48 mumol CO2 m-2 s -1, and the lagoon mangroves showed the highest uptake of -8.11 mumol CO2 m-2 s-1. Additional simultaneous measurements of NDVI allowed simple linear modeling of CO2 flux as a function of NDVI for the mangroves of the Magdalena Bay region. In the second part of this research, the spatial variability of ecosystem fluxes across the 1802 km2 Barrow Peninsula region was studied. During typical 2006 summer conditions, the midday hourly CO2 flux over the region was -2.04 x 105 kgCO2 hr-1. The CO2 fluxes among the interstitial tundra, Ancient and Old VDTLBs, as well as between the Medium and Young VDTLBs were not significantly different. Combined, the interstitial tundra and Old and Ancient

  16. Comparative metabolomics and structural characterizations illuminate colibactin pathway-dependent small molecules.

    PubMed

    Vizcaino, Maria I; Engel, Philipp; Trautman, Eric; Crawford, Jason M

    2014-07-02

    The gene cluster responsible for synthesis of the unknown molecule "colibactin" has been identified in mutualistic and pathogenic Escherichia coli. The pathway endows its producer with a long-term persistence phenotype in the human bowel, a probiotic activity used in the treatment of ulcerative colitis, and a carcinogenic activity under host inflammatory conditions. To date, functional small molecules from this pathway have not been reported. Here we implemented a comparative metabolomics and targeted structural network analyses approach to identify a catalog of small molecules dependent on the colibactin pathway from the meningitis isolate E. coli IHE3034 and the probiotic E. coli Nissle 1917. The structures of 10 pathway-dependent small molecules are proposed based on structural characterizations and network relationships. The network will provide a roadmap for the structural and functional elucidation of a variety of other small molecules encoded by the pathway. From the characterized small molecule set, in vitro bacterial growth inhibitory and mammalian CNS receptor antagonist activities are presented.

  17. A Tale of Two Small Business Grants: The Best of Times, the Worst of Times from the NASA Ames Small Business Innovative Research (SBIR) Program

    NASA Technical Reports Server (NTRS)

    Kojiro, Daniel R.; Lee, Geoffrey S.

    2006-01-01

    The purposes of the SBIR Program are to: stimulate technological innovation in the private sector; strengthen the role of Small Business Concerns (SBCs) in meeting Federal research and development needs; increase the commercial application of these research results; and encourage participation of socially and economically disadvantaged persons and women-owned small businesses. The process can be highly rewarding, providing the small business with resources to pursue research and development with a focus on providing NASA with new and advanced capabilities. We present two examples of how the NASA Ames SBIR Program has addressed these purposes, nurturing innovative ideas from small, businesses into commercially viable products that also address analytical needs in space research. These examples, from the Science Instruments for Conducting Solar System Exploration Subtopic, describe the journey from innovative concept to analytical instrument, one successful and one hampered by numerous roadblocks (including some international intrigue}.

  18. Small copper clusters studied by x-ray absorption near-edge structure

    NASA Astrophysics Data System (ADS)

    Oyanagi, H.; Sun, Z. H.; Jiang, Y.; Uehara, M.; Nakamura, H.; Yamashita, K.; Orimoto, Y.; Zhang, L.; Lee, C.; Fukano, A.; Maeda, H.

    2012-04-01

    The local structure of copper nanoparticles grown in organic solution by reducing Cu(II) hexafluoroacetylacetonate [Cu(hfac)2] was studied as-grown by the Cu K-edge x-ray absorption near-edge structure (XANES). Comparison of the experimental XANES spectra with reference materials indicated small copper clusters are formed by ligand-exchange with oleylamine and subsequent reducing by diphenylsilane. The multiple-scattering (MS) calculation for various model clusters consisting of 13-135 atoms suggests that small (13-19 atom) Cu clusters are stabilized without a large deformation.

  19. Fabrication of small-scale structures with non-planar features

    DOEpatents

    Burckel, David B.; Ten Eyck, Gregory A.

    2015-11-19

    The fabrication of small-scale structures is disclosed. A unit-cell of a small-scale structure with non-planar features is fabricated by forming a membrane on a suitable material. A pattern is formed in the membrane and a portion of the substrate underneath the membrane is removed to form a cavity. Resonators are then directionally deposited on the wall or sides of the cavity. The cavity may be rotated during deposition to form closed-loop resonators. The resonators may be non-planar. The unit-cells can be formed in a layer that includes an array of unit-cells.

  20. Fabrication method for small-scale structures with non-planar features

    DOEpatents

    Burckel, David Bruce; Ten Eyck, Gregory A.

    2016-09-20

    The fabrication of small-scale structures is disclosed. A unit-cell of a small-scale structure with non-planar features is fabricated by forming a membrane on a suitable material. A pattern is formed in the membrane and a portion of the substrate underneath the membrane is removed to form a cavity. Resonators are then directionally deposited on the wall or sides of the cavity. The cavity may be rotated during deposition to form closed-loop resonators. The resonators may be non-planar. The unit-cells can be formed in a layer that includes an array of unit-cells.

  1. Silica glass structure generation for ab initio calculations using small samples of amorphous silica

    NASA Astrophysics Data System (ADS)

    van Ginhoven, Renée M.; Jónsson, Hannes; Corrales, L. René

    2005-01-01

    Multiple small samples of amorphous silica have been generated and optimized using classical dynamics and the van Beest-Kramer-van Santen (BKS) empirical potential function. The samples were subsequently optimized and annealed using density functional theory (DFT) with both the local density and the generalized gradient approximations. A thorough analysis of the local and medium-range structure of the optimized samples obtained from the different methods was carried out. The structural characteristics obtained for the average of small systems each containing ca. 100 ions are compared for each of the different methods, and to the BKS simulation of a larger system. The differences found between the DFT and BKS simulations and the effects of volume relaxation on the structures are discussed. Fixed-volume samples are compared to neutron scattering data, with good agreement to 5Å , the length limit of the sample sizes used here. It is shown that by creating multiple small samples, it is possible to achieve a good statistical sampling of structural features consistent with larger simulated glass systems. This study also shows that multiple small samples are necessary to capture the structural distribution of silica glass, and therefore to study more complex processes in glass, such as reactions.

  2. Graph analysis of structural brain networks in Alzheimer's disease: beyond small world properties.

    PubMed

    John, Majnu; Ikuta, Toshikazu; Ferbinteanu, Janina

    2017-03-01

    Changes in brain connectivity in patients with early Alzheimer's disease (AD) have been investigated using graph analysis. However, these studies were based on small data sets, explored a limited range of network parameters, and did not focus on more restricted sub-networks, where neurodegenerative processes may introduce more prominent alterations. In this study, we constructed structural brain networks out of 87 regions using data from 135 healthy elders and 100 early AD patients selected from the Open Access Series of Imaging Studies (OASIS) database. We evaluated the graph properties of these networks by investigating metrics of network efficiency, small world properties, segregation, product measures of complexity, and entropy. Because degenerative processes take place at different rates in different brain areas, analysis restricted to sub-networks may reveal changes otherwise undetected. Therefore, we first analyzed the graph properties of a network encompassing all brain areas considered together, and then repeated the analysis after dividing the brain areas into two sub-networks constructed by applying a clustering algorithm. At the level of large scale network, the analysis did not reveal differences between AD patients and controls. In contrast, the same analysis performed on the two sub-networks revealed that small worldness diminished with AD only in the sub-network containing the areas of medial temporal lobe known to be heaviest and earliest affected. The second sub-network, which did not present significant AD-induced modifications of 'classical' small world parameters, nonetheless showed a trend towards an increase in small world propensity, a novel metric that unbiasedly quantifies small world structure. Beyond small world properties, complexity and entropy measures indicated that the intricacy of connection patterns and structural diversity decreased in both sub-networks. These results show that neurodegenerative processes impact volumetric

  3. Developmental research as a way to an empirically based didactical structure of science

    NASA Astrophysics Data System (ADS)

    Lijnse, P. L.

    In the past decades, much work has been done in science education on large-scale curriculum development, ranging from a structure-of-the-discipline approach to STS. At the same time, research on students' ideas has drawn attention to the underestimated problems of learning and teaching, which may largely explain the limited success of the curriculum efforts as far as cognitive learning is concerned. Proposed solutions are mainly inspired by a constructivist cognitive science perspective and are formulated as general teaching strategies that aim at a more or less forced process of conceptual change. However, in our view, developmental research is needed in which small-scale curriculum development is cyclically coupled to indepth classroom research of teaching-learning processes. Such research should resuit in worked out examples of successful ways of teaching, according to new conceptual curriculum structures. Designing such didactical structures constitutes a longer term research program, which asks for international exchange and cooperation.

  4. Structural dynamics branch research and accomplishments for fiscal year 1987

    NASA Technical Reports Server (NTRS)

    1988-01-01

    This publication contains a collection of fiscal year 1987 research highlights from the Structural Dynamics Branch at NASA Lewis Research Center. Highlights from the branch's four major work areas, Aeroelasticity, Vibration Control, Dynamic Systems, and Computational Structural Methods, are included in the report as well as a complete listing of the FY87 branch publications.

  5. Rhetorical Structure of Research Articles in Agricultural Science

    ERIC Educational Resources Information Center

    Shi, Huimin; Wannaruk, Anchalee

    2014-01-01

    Although the rhetorical structure of research articles (RA) has been extensively examined from individual sections to complete IMRD sections regarding different disciplines, no research has been addressed to the overall rhetorical structure of RAs as a whole entity in the field of agricultural science. In this study, we analyzed 45 agricultural…

  6. Structural Dynamics Branch research and accomplishments for FY 1990

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Presented here is a collection of FY 1990 research highlights from the Structural Dynamics Branch at the NASA Lewis Research Center. Highlights are from the branch's major work areas: aeroelasticity, vibration control, dynamic systems, and computational structural methods. A listing is given of FY 1990 branch publications.

  7. Structural dynamics branch research and accomplishments for FY 1988

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Fiscal year 1988 research highlights from the Structural Dynamics Branch at NASA Lewis Research Center are described. Highlights from the branch's major work areas -- aeroelasticity, vibration control, dynamic systems, and computational structural methods -- are included as well as a complete listing of the FY 88 branch publications.

  8. Organisation of autonomic nervous structures in the small intestine of chinchilla (Chinchilla laniger, Molina).

    PubMed

    Nowak, E

    2014-08-01

    Using histochemical, histological and immunocytochemical methods, organisation of the autonomic nerve structures in small intestine of chinchilla was investigated. Myenteric plexus was localised between circular and longitudinal layers of the smooth muscles. Forming network nodes, the small autonomic, cholinergic ganglia were linked with the bundles of nerve fibres. Adrenergic structures were visible as specific varicose, rosary-like fibres forming bundles of parallel fibres connecting network nodes. Structures of the submucosal plexus formed a finer network than those of the myenteric plexus. Moreover, in 'whole-mount' specimens, fibres forming thick perivascular plexuses were also observed. Immunocytochemical studies confirmed the cholinergic and adrenergic character of the investigated structures. VAChT-positive neurones were found only in myenteric plexus, and numerous VAChT-positive and DBH-positive fibres were found in both plexuses.

  9. Clustering Methods with Qualitative Data: a Mixed-Methods Approach for Prevention Research with Small Samples.

    PubMed

    Henry, David; Dymnicki, Allison B; Mohatt, Nathaniel; Allen, James; Kelly, James G

    2015-10-01

    Qualitative methods potentially add depth to prevention research but can produce large amounts of complex data even with small samples. Studies conducted with culturally distinct samples often produce voluminous qualitative data but may lack sufficient sample sizes for sophisticated quantitative analysis. Currently lacking in mixed-methods research are methods allowing for more fully integrating qualitative and quantitative analysis techniques. Cluster analysis can be applied to coded qualitative data to clarify the findings of prevention studies by aiding efforts to reveal such things as the motives of participants for their actions and the reasons behind counterintuitive findings. By clustering groups of participants with similar profiles of codes in a quantitative analysis, cluster analysis can serve as a key component in mixed-methods research. This article reports two studies. In the first study, we conduct simulations to test the accuracy of cluster assignment using three different clustering methods with binary data as produced when coding qualitative interviews. Results indicated that hierarchical clustering, K-means clustering, and latent class analysis produced similar levels of accuracy with binary data and that the accuracy of these methods did not decrease with samples as small as 50. Whereas the first study explores the feasibility of using common clustering methods with binary data, the second study provides a "real-world" example using data from a qualitative study of community leadership connected with a drug abuse prevention project. We discuss the implications of this approach for conducting prevention research, especially with small samples and culturally distinct communities.

  10. Magnetic Properties of Surface Sediments in Small Temperate Lakes: Modern Analogues for Paleolimnologic Research

    NASA Astrophysics Data System (ADS)

    Lascu, I.; Plank, C.

    2007-12-01

    Magnetic properties of lake sediments are routinely measured as part of paleolimnological and paleoclimatic research. Basic parameters such as magnetic susceptibility (MS), anhysteretic remanent magnetization (ARM), and isothermal remanent magnetization (IRM) are used for correlating cores from different sites in the same basin, tracking erosion history and lake level changes, or investigating eutrophication and microbial processes. However, a detailed investigation of the syn-depositional processes that control the distribution of magnetic minerals across lake basins is lacking for most types of lake systems. In order to understand the main controls on environmental magnetic records, we systematically investigated the magnetic properties of surface sediments collected along transects in nine Minnesota lakes. The lakes are small (<1 sq. km), have simple morphologies, are hydrologically closed, and are distributed across an east-west moisture gradient, as well as a north-south temperature gradient. The structure of lake water columns was investigated by measuring temperature, specific conductivity, dissolved oxygen, and pH. Sediment composition was determined via loss on ignition (LOI). The magnetic properties of the sediments reflect the change in depositional environments from shallow to deep water, as defined in sedimentological context by LOI and sediment granulometry. All lake basins exhibit a characteristic pattern in terms of concentration (MS and IRM) and grain size (ARM/IRM) of magnetic minerals. Sediments above wave base (0.5 m) have high concentrations of coarse grained magnetic minerals. Below wave base, but in the thermally mixed layer, magnetic particles are finer-grained and present in lower concentrations. Profundal slope sediments are characterized by variable magnetic and compositional parameters, indicative of a dynamic sedimentological and geochemical environment. In the deep, anoxic regions, magnetic concentration increases again, associated

  11. Small Business Innovation Research. Program solicitation. Closing date: July 21, 1992

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The National Aeronautics and Space Administration (NASA) invites small businesses to submit Phase 1 proposals in response to its Small Business Innovation Research (SBIR) Program Solicitation 92-1. Firms with research or research and development capabilities (R/R&D) in science or engineering in any of the areas listed are encouraged to participate. This, the tenth annual SBIR solicitation by NASA, describes the program, identifies eligibility requirements, describes the proposal evaluation and award selection process, and provides other information to assist those interested in participating in NASA's SBIR program. It also identifies, in Section 8.0, the technical topics and subtopics in which SBIR Phase 1 proposals are solicited in 1992. These topics and subtopics cover a broad range of current NASA interests but do not necessarily include all areas in which NASA plans or currently conducts research. The NASA SBIR program seeks innovative approaches that respond to the needs, technical requirements, and new opportunities described in the subtopics. The focus is on innovation through the use of emerging technologies, novel applications of existing technologies, exploitation of scientific breakthroughs, or new capabilities or major improvements to existing technologies. NASA plans to select about 320 high-quality research or research and development proposals for Phase 1 contract awards on the basis of this Solicitation. Phase 1 contracts are normally six months in duration and funded up to $50,000, including profit. Selections will be based on the competitive merits of the offers and on NASA needs and priorities.

  12. Development of the West Virginia University Small Microgravity Research Facility (WVU SMiRF)

    NASA Astrophysics Data System (ADS)

    Phillips, Kyle G.

    West Virginia University (WVU) has created the Small Microgravity Research Facility (SMiRF) drop tower through a WVU Research Corporation Program to Stimulate Competitive Research (PSCoR) grant on its campus to increase direct access to inexpensive and repeatable reduced gravity research. In short, a drop tower is a tall structure from which experimental payloads are dropped, in a controlled environment, and experience reduced gravity or microgravity (i.e. "weightlessness") during free fall. Currently, there are several methods for conducting scientific research in microgravity including drop towers, parabolic flights, sounding rockets, suborbital flights, NanoSats, CubeSats, full-sized satellites, manned orbital flight, and the International Space Station (ISS). However, none of the aforementioned techniques is more inexpensive or has the capability of frequent experimentation repeatability as drop tower research. These advantages are conducive to a wide variety of experiments that can be inexpensively validated, and potentially accredited, through repeated, reliable research that permits frequent experiment modification and re-testing. Development of the WVU SMiRF, or any drop tower, must take a systems engineering approach that may include the detailed design of several main components, namely: the payload release system, the payload deceleration system, the payload lifting and transfer system, the drop tower structure, and the instrumentation and controls system, as well as a standardized drop tower payload frame for use by those researchers who cannot afford to spend money on a data acquisition system or frame. In addition to detailed technical development, a budgetary model by which development took place is also presented throughout, summarized, and detailed in an appendix. After design and construction of the WVU SMiRF was complete, initial calibration provided performance characteristics at various payload weights, and full-scale checkout via

  13. Research in Structures, Structural Dynamics and Materials, 1990

    NASA Technical Reports Server (NTRS)

    Barthelemy, Jean-Francois M. (Compiler); Noor, Ahmed K. (Compiler)

    1990-01-01

    The Structural Dynamics and Materials (SDM) Conference was held on April 2 to 4, 1990 in Long Beach, California. This publication is a compilation of presentations of the work-in-progress sessions and does not contain papers from the regular sessions since those papers are published by AIAA in the conference proceedings.

  14. Rhetorical Structure of Biochemistry Research Articles

    ERIC Educational Resources Information Center

    Kanoksilapatham, Budsaba

    2005-01-01

    This paper reports on the results of a move analysis [Swales, J. (1990). "Genre analysis." Cambridge: Cambridge University Press] of 60 biochemistry research articles. First, a corpus was systematically compiled to ensure that it represents core journals in the focused discipline. Then, coding reliability analysis was conducted to…

  15. Research in nonlinear structural and solid mechanics

    NASA Technical Reports Server (NTRS)

    Mccomb, H. G., Jr. (Compiler); Noor, A. K. (Compiler)

    1980-01-01

    Nonlinear analysis of building structures and numerical solution of nonlinear algebraic equations and Newton's method are discussed. Other topics include: nonlinear interaction problems; solution procedures for nonlinear problems; crash dynamics and advanced nonlinear applications; material characterization, contact problems, and inelastic response; and formulation aspects and special software for nonlinear analysis.

  16. Structure and Agency in Transition Research

    ERIC Educational Resources Information Center

    Heinz, Walter R.

    2009-01-01

    Based on the results of transition studies in the UK, Germany, USA and Canada, the virtues of analysing the structural contexts, institutional arrangements and the young peoples' action orientations are presented. In the first decade of the twenty-first century, school and the labour market have become more and more decoupled and transition routes…

  17. The Use of Additive Manufacturing for Fabrication of Multi-Function Small Satellite Structures

    SciTech Connect

    Horais, Brian J; Love, Lonnie J; Dehoff, Ryan R

    2013-01-01

    The use of small satellites in constellations is limited only by the growing functionality of smallsats themselves. Additive manufacturing provides exciting new design opportunities for development of multifunction CubeSat structures that integrate such functions as propulsion and thermal control into the satellite structures themselves. Manufacturing of these complex multifunction structures is now possible in lightweight, high strength, materials such as titanium by using existing electron beam melting additive manufacturing processes. However, the use of today's additive manufacturing capabilities is often cost-prohibitive for small companies due to the large capital investments required. To alleviate this impediment the U.S. Department of Energy has established a Manufacturing Demonstration Facility (MDF) at their Oak Ridge National Laboratory (ORNL) in Tennessee that provides industry access to a broad range of energy-efficient additive manufacturing equipment for collaborative use by both small and large organizations. This paper presents a notional CubeSat multifunction design that integrates the propulsion system into a three-unit (3U) CubeSat structure. The full-scale structure has been designed and fabricated at the ORNL MDF. The use of additive manufacturing for spacecraft fabrication is opening up many new possibilities in design and fabrication capabilities for what had previously been impossible structures to fabricate.

  18. Low-rank network decomposition reveals structural characteristics of small-world networks

    NASA Astrophysics Data System (ADS)

    Barranca, Victor J.; Zhou, Douglas; Cai, David

    2015-12-01

    Small-world networks occur naturally throughout biological, technological, and social systems. With their prevalence, it is particularly important to prudently identify small-world networks and further characterize their unique connection structure with respect to network function. In this work we develop a formalism for classifying networks and identifying small-world structure using a decomposition of network connectivity matrices into low-rank and sparse components, corresponding to connections within clusters of highly connected nodes and sparse interconnections between clusters, respectively. We show that the network decomposition is independent of node indexing and define associated bounded measures of connectivity structure, which provide insight into the clustering and regularity of network connections. While many existing network characterizations rely on constructing benchmark networks for comparison or fail to describe the structural properties of relatively densely connected networks, our classification relies only on the intrinsic network structure and is quite robust with respect to changes in connection density, producing stable results across network realizations. Using this framework, we analyze several real-world networks and reveal new structural properties, which are often indiscernible by previously established characterizations of network connectivity.

  19. Modeling the Structure of RNA Molecules with Small-Angle X-Ray Scattering Data

    PubMed Central

    Gajda, Michal Jan; Martinez Zapien, Denise; Uchikawa, Emiko; Dock-Bregeon, Anne-Catherine

    2013-01-01

    We propose a novel fragment assembly method for low-resolution modeling of RNA and show how it may be used along with small-angle X-ray solution scattering (SAXS) data to model low-resolution structures of particles having as many as 12 independent secondary structure elements. We assessed this model-building procedure by using both artificial data on a previously proposed benchmark and publicly available data. With the artificial data, SAXS-guided models show better similarity to native structures than ROSETTA decoys. The publicly available data showed that SAXS-guided models can be used to reinterpret RNA structures previously deposited in the Protein Data Bank. Our approach allows for fast and efficient building of de novo models of RNA using approximate secondary structures that can be readily obtained from existing bioinformatic approaches. We also offer a rigorous assessment of the resolving power of SAXS in the case of small RNA structures, along with a small multimetric benchmark of the proposed method. PMID:24223750

  20. Structural basis for small molecule targeting of the programmed death ligand 1 (PD-L1)

    PubMed Central

    Zak, Krzysztof M.; Grudnik, Przemyslaw; Guzik, Katarzyna; Zieba, Bartosz J.; Musielak, Bogdan; Dömling, Alexander; Dubin, Grzegorz; Holak, Tad A.

    2016-01-01

    Targeting the PD-1/PD-L1 immunologic checkpoint with monoclonal antibodies has provided unprecedented results in cancer treatment in the recent years. Development of chemical inhibitors for this pathway lags the antibody development because of insufficient structural information. The first nonpeptidic chemical inhibitors that target the PD-1/PD-L1 interaction have only been recently disclosed by Bristol-Myers Squibb. Here, we show that these small-molecule compounds bind directly to PD-L1 and that they potently block PD-1 binding. Structural studies reveal a dimeric protein complex with a single small molecule which stabilizes the dimer thus occluding the PD-1 interaction surface of PD-L1s. The small-molecule interaction “hot spots” on PD-L1 surfaces suggest approaches for the PD-1/PD-L1 antagonist drug discovery. PMID:27083005

  1. High Power Microwave Emission of Large and Small Orbit Gyrotron Devices in Rectangular Interaction Structures

    NASA Astrophysics Data System (ADS)

    Hochman, J. M.; Gilgenbach, R. M.; Jaynes, R. L.; Rintamaki, J. I.; Luginsland, J. W.; Lau, Y. Y.; Spencer, T. A.

    1996-11-01

    Experiments utilize large and small orbit e-beam gyrotron devices in a rectangular-cross-section (RCS) gyrotron. This device is being explored to examine polarization control. Other research issues include pulse shortening, and mode competition. MELBA generates electron beams with parameters of: -800kV, 1-10kA diode current, and 0.5-1.0 μ sec pulselengths. The small orbit gyrotron device is converted to a large orbit experiment by running MELBA's annular electron beam through a magnetic cusp. Initial experiments showed an increase in beam alpha (V_perp/V_par) of a factor of ~ 4 between small and large orbit devices. Experimental results from the RCS gyrotron will be compared for large-orbit and small-orbit electron beams. Beam transport data and frequency measurements will be presented. Computer modeling utilizing the MAGIC and E-gun codes will be shown.

  2. Rhetorical Structure of Education Research Article Methods Sections

    ERIC Educational Resources Information Center

    Zhang, Baoya; Wannaruk, Anchalee

    2016-01-01

    This study investigated the rhetorical move structure of the education research article genre within the framework of Swales' (1981, 1990, 2004) move analysis. A corpus of 120 systematically sampled empirical education research articles served as data input for the analysis. The results indicate that the education research article methods section…

  3. Structural Interventions: Concepts, Challenges and Opportunities for Research

    PubMed Central

    Friedman, S. R.; Dworkin, S.; Mantell, J. E.

    2006-01-01

    Structural interventions refer to public health interventions that promote health by altering the structural context within which health is produced and reproduced. They draw on concepts from multiple disciplines, including public health, psychiatry, and psychology, in which attention to interventions is common, and sociology and political economy, where structure is a familiar, if contested, concept. This has meant that even as discussions of structural interventions bring together researchers from various fields, they can get stalled in debates over definitions. In this paper, we seek to move these discussions forward by highlighting a number of critical issues raised by structural interventions, and the subsequent implications of these for research. PMID:16736355

  4. Evaluating Small Sample Approaches for Model Test Statistics in Structural Equation Modeling

    ERIC Educational Resources Information Center

    Nevitt, Jonathan; Hancock, Gregory R.

    2004-01-01

    Through Monte Carlo simulation, small sample methods for evaluating overall data-model fit in structural equation modeling were explored. Type I error behavior and power were examined using maximum likelihood (ML), Satorra-Bentler scaled and adjusted (SB; Satorra & Bentler, 1988, 1994), residual-based (Browne, 1984), and asymptotically…

  5. Structure of the Anthrax Research Literature

    DTIC Science & Technology

    2006-01-01

    number tandem repeat [VNTR] analysis) (Keim et al., 2000) to identify the strain of B. anthracis used in the attack. Additional forensic information...3; magyar allatorvosok lapja 3; journal of the kansas entomological society 3; archives of internal medicine 3 Keywords infectious diseases 37...infectious diseases 4; american journal of public health 4; journal of the kansas entomological society 3; onderstepoort journal of veterinary research 2

  6. NASA's Management and Utilization of the Small Business Innovative Research (SBIR) Program

    NASA Technical Reports Server (NTRS)

    Mexcur, Winfield Paul

    2003-01-01

    The United Space Congress established the SBIR program in 1982 for the following purposes: ( 1) Stimulate technological innovation (2) Increase private-sector commercialization derived from federal R&D (3) Use small business to meet federal R&D needs (4) Foster and encourage participation by disadvantaged persons and women in technological innovation The STTR program was established in 1992 with the additional requirement of having a small business partner with a research institution (usually a university) for the purpose of transferring intellectual property from the research institution to the small business concern for enabling a government technical need and furthering the technological development for the purpose of developing commercial products. The government of Japan has established a program that models portions of the U.S. SBIR and STTR programs. They are very interested in how NASA has been so successful in fulfilling the Congressional objectives of these programs. In particular, they want to understand the management practices and incentives that are provided to enable partnerships between business enterprises, academia and government. The speech will also focus on some of the many successful technologies (on a conceptual level) that have been developed through NASA s SBIR and STTR programs and mechanisms used to promote cooperation between small businesses, large businesses, academia and government agencies within the United States. The speech is on a conceptual level, focusing on U.S. and NASA policies and management implementation practices. No enabling technical discussion will be held.

  7. sRNAtoolbox: an integrated collection of small RNA research tools

    PubMed Central

    Rueda, Antonio; Barturen, Guillermo; Lebrón, Ricardo; Gómez-Martín, Cristina; Alganza, Ángel; Oliver, José L.; Hackenberg, Michael

    2015-01-01

    Small RNA research is a rapidly growing field. Apart from microRNAs, which are important regulators of gene expression, other types of functional small RNA molecules have been reported in animals and plants. MicroRNAs are important in host-microbe interactions and parasite microRNAs might modulate the innate immunity of the host. Furthermore, small RNAs can be detected in bodily fluids making them attractive non-invasive biomarker candidates. Given the general broad interest in small RNAs, and in particular microRNAs, a large number of bioinformatics aided analysis types are needed by the scientific community. To facilitate integrated sRNA research, we developed sRNAtoolbox, a set of independent but interconnected tools for expression profiling from high-throughput sequencing data, consensus differential expression, target gene prediction, visual exploration in a genome context as a function of read length, gene list analysis and blast search of unmapped reads. All tools can be used independently or for the exploration and downstream analysis of sRNAbench results. Workflows like the prediction of consensus target genes of parasite microRNAs in the host followed by the detection of enriched pathways can be easily established. The web-interface interconnecting all these tools is available at http://bioinfo5.ugr.es/srnatoolbox PMID:26019179

  8. Simulation and experiment research of aerodynamic performance of small axial fans with struts

    NASA Astrophysics Data System (ADS)

    Chu, Wei; Lin, Peifeng; Zhang, Li; Jin, Yingzi; Wang, Yanping; Kim, Heuy Dong; Setoguchi, Toshiaki

    2016-06-01

    Interaction between rotor and struts has great effect on the performance of small axial fan systems. The small axial fan systems are selected as the studied objects in this paper, and four square struts are downstream of the rotor. The cross section of the struts is changed to the cylindrical shapes for the investigation: one is in the same hydraulic diameter as the square struts and another one is in the same cross section as the square struts. Influence of the shape of the struts on the static pressure characteristics, the internal flow and the sound emission of the small axial fans are studied. Standard K-ɛ turbulence model and SIMPLE algorithm are applied in the calculation of the steady fluid field, and the curves of the pressure rising against the flow rate are obtained, which demonstrates that the simulation results are in nice consistence with the experimental data. The steady calculation results are set as the initial field in the unsteady calculation. Large eddy simulation and PISO algorithm are used in the transient calculation, and the Ffowcs Williams-Hawkings model is introduced to predict the sound level at the eight monitoring points. The research results show that: the static pressure coefficients of the fan with cylindrical struts increase by about 25% compared to the fan with square struts, and the efficiencies increase by about 28.6%. The research provides a theoretical guide for shape optimization and noise reduction of small axial fan with struts.

  9. Small karstic Dobra River (Croatia) suggested as natural laboratory for impactite research

    NASA Astrophysics Data System (ADS)

    Frančišković-Bilinski, Stanislav; Bilinski, Halka; Sikder, Arif M.

    2016-04-01

    An unexpected anomaly of magnetic susceptibility (MS) was observed in stream sediments of the upper course of the karstic Dobra River (Croatia). Preliminary results pointed to a possible impactite, formed by a shock event caused by a meteorite impact or by volcanic processes [1]. In addition to geophysical experiments, petrological and geochemical studies are reported [2, 3]. The multidisciplinary work for identification and confirmation of impact structure is still in progress. Results will be presented and the difficulties due to weathering and transport processes will be discussed and compared with recent literature [4, 5]. In reported results numerous evidences exist, which are in support of impact origin, such as vesicular glass with quench texture, ballen textures in the lechatelierite, presence of Troilite, etc. We suggest that the Dobra River from its source to the abyss in Ogulin (Upper Dobra) is a possible natural laboratory for studying processes of mixing between impactite material and fluvial sediments within a small area, including spherules exposed to water and in the overbank sediments. Especially the introduction of isotope studies in this research and enlargement of multinational team of experts are suggested. Literature: [1] Franči\\vsković-Bilinski, S., Bilinski, H., Scholger, R., Tomašić, N., Maldini, K. (2014): Magnetic spherules in sediments of the sinking karstic Dobra River (Croatia). Journal of soils and sediments 14(3), 600-614. [2] Franči\\vsković-Bilinski, S., Sikder, A.M., Bilinski, H., Castano, C.E., Garman, G.C. (2015): Traces of meteorite impact in the sediments of karstic Dobra River (Croatia). 15th International multidisciplinary scientific geoconference SGEM 2015 Conference proceedings, Vol. 1, 507-514. [3] Sikder, A.M., Franči\\vsković-Bilinski, S., Bilinski, H., Castano, C.E., Clifford, D.M., Turner, J.B., Garman, G.C. (2015): Petrographic analysis of the magnetic spherules from the sediments of karastic Dobra River

  10. Research in nonlinear structural and solid mechanics

    NASA Technical Reports Server (NTRS)

    Mccomb, H. G., Jr. (Compiler); Noor, A. K. (Compiler)

    1981-01-01

    Recent and projected advances in applied mechanics, numerical analysis, computer hardware and engineering software, and their impact on modeling and solution techniques in nonlinear structural and solid mechanics are discussed. The fields covered are rapidly changing and are strongly impacted by current and projected advances in computer hardware. To foster effective development of the technology perceptions on computing systems and nonlinear analysis software systems are presented.

  11. Multiple size scale structures in silica/siloxane composites studied by small-angle scattering

    SciTech Connect

    Beaucage, G.; Schaefer, D.W.; Ulibarri, T.; Black, E.

    1993-12-31

    The physical properties of in-situ produced composites, such as the TEOS-polysiloxane based systems, are directly related to the complex interaction of structural features from the nano- to macro-scopic scales. The nature of these structural interactions are a key element in understanding and controlling mechanical properties in these systems. We believe that the smallest scale structures, in the nanometer range, correlate with properties such as the modulus while large-scale structures on the micron scale effect failure in these materials. This paper discusses techniques for analysis of structural features and interrelation of structural features over these wide ranges of size using small-angle light, x-ray and neutron scattering. Combination of data from different instruments allows for characterization of the interaction between these different size scale features.

  12. Small Business Innovation Research. Program solicitation. Closing date: July 22, 1988

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The sixth annual Small Business Innovation Research (SBIR) solicitation by NASA, describes the program, identifies eligibility requirements, outlines proposal preparation and submission requirements, describes the proposal evaluation and award selection process, and provides other information to assist those interested in participating in the SBIR program. It also identifies in Section 8.0 and Appendix D, the specific technical topics and subtopics in which SBIR Phase 1 proposals are solicited in 1988.

  13. Complex sound stimuli representation by small neural groups in subcortical auditory structure

    NASA Astrophysics Data System (ADS)

    Lyzwa, Dominika

    The neural representation of complex natural sound stimuli in higher auditory structures is not yet well understood. Based on neurophysiological recordings from the mammalian auditory midbrain, neural responses to complex (natural and also artificial) sounds are investigated and mapped with respect to temporal and spectral neural tuning in the subcortical structure. The mapping includes spiking activity of single neurons and small neural clusters and local field potential activity. A neural model is presented which captures the mapping and also the similarity of responses across the auditory structure, and is used to predict responses to novel sound. Financial support by Bernstein Focus Neural Technology Goettingen, Grant Number #01GQ0811.

  14. A multifractal representation of the small-scale structure in a turbulent plume

    SciTech Connect

    Sykes, R.I.; Gabruk, R.S.; Hen, D.S.

    1995-10-01

    An improved method for representing the small-scale structure of a turbulent scalar field using fractal recursion techniques is described. The model generalizes the fractal successive refinement method described by Sykes and Gabruk to include a more realistic description of the pseudodissipation field, that is, the square of the scalar gradient. Turbulent dissipation fields are known to be multifractal, so a multifractal generation technique has been incorporated into the fractal refinement model to yield a scalar field with fractal isosurfaces but with a multifractal pseudodissipation field. The model fields are compared with realizations from large-eddy simulations of turbulent scalar dispersion and shown to provide improved agreement with the small-scale structure. The simple combination of fractal and multifractal properties employed in the model also provides insight into the structure of the random scalar field. Finally, the generation technique is completely localized in physical space and is therefore applicable to inhomogeneous fields. 17 refs., 19 figs.

  15. Ordering of small particles in one-dimensional coherent structures by time-periodic flows.

    PubMed

    Pushkin, D O; Melnikov, D E; Shevtsova, V M

    2011-06-10

    Small particles transported by a fluid medium do not necessarily have to follow the flow. We show that for a wide class of time-periodic incompressible flows inertial particles have a tendency to spontaneously align in one-dimensional dynamic coherent structures. This effect may take place for particles so small that often they would be expected to behave as passive tracers and be used in PIV measurement technique. We link the particle tendency to form one-dimensional structures to the nonlinear phenomenon of phase locking. We propose that this general mechanism is, in particular, responsible for the enigmatic formation of the "particle accumulation structures" discovered experimentally in thermocapillary flows more than a decade ago and unexplained until now.

  16. Micelle structural studies on oil solubilization by a small-angle neutron scattering

    NASA Astrophysics Data System (ADS)

    Putra, Edy Giri Rachman; Seong, Baek Seok; Ikram, Abarrul

    2009-02-01

    A small-angle neutron scattering (SANS) technique was applied to reveal the micelle structural changes. The micelle structural changes of 0.3 M sodium dodecyl sulfate (SDS) concentration by addition of various oil, i.e. n-hexane, n-octane, and n-decane up to 60% (v/v) have been investigated. It was found that the size, aggregation number and the structures of the micelles changed exhibiting that the effective charge on the micelle decreases with an addition of oil. There was a small increase in minor axis of micelle while the correlation peak shifted to a lower momentum transfer Q and then to higher Q by a further oil addition.

  17. Correlating Molecular Structures with Transport Dynamics in High-Efficiency Small-Molecule Organic Photovoltaics.

    PubMed

    Peng, Jiajun; Chen, Yani; Wu, Xiaohan; Zhang, Qian; Kan, Bin; Chen, Xiaoqing; Chen, Yongsheng; Huang, Jia; Liang, Ziqi

    2015-06-24

    Efficient charge transport is a key step toward high efficiency in small-molecule organic photovoltaics. Here we applied time-of-flight and organic field-effect transistor to complementarily study the influences of molecular structure, trap states, and molecular orientation on charge transport of small-molecule DRCN7T (D1) and its analogue DERHD7T (D2). It is revealed that, despite the subtle difference of the chemical structures, D1 exhibits higher charge mobility, the absence of shallow traps, and better photosensitivity than D2. Moreover, charge transport is favored in the out-of-plane structure within D1-based organic solar cells, while D2 prefers in-plane charge transport.

  18. Landau theory of crystallization and the capsid structures of small icosahedral viruses

    NASA Astrophysics Data System (ADS)

    Lorman, V. L.; Rochal, S. B.

    2008-06-01

    A new approach to the capsid structures of small viruses with spherical topology and icosahedral symmetry is proposed. It generalizes Landau theory of crystallization to describe icosahedral viral shells self-assembled from identical asymmetric proteins. An explicit method which predicts the positions of centers of mass for the proteins constituting the shell is discussed in detail. The method is based on irreducible density distribution function which generates the protein positions. The universal form of the density distribution function which contains no fitting parameter permits to classify the capsids structures of small viruses. The theory describes in a uniform way both the structures satisfying the well-known Caspar and Klug geometrical model for capsid construction and those violating it. A group theory analysis of the Caspar and Klug model and of the “quasiequivalence” principle for protein environments in viral capsids is given. The molecular basis of difference in protein environments and peculiarities in the assembly thermodynamics are also discussed.

  19. Poetic forms and structures in qualitative health research.

    PubMed

    Furman, Rich

    2006-04-01

    In this article, the author explores the uses of poetic forms in qualitative health research, analyzing thematically a poem written from a patient's perspective of being treated in an emergency room. From the themes identified, he created two "research poems" using two formal poetic structures: the French-Malaysian pantoum, and the Japanese-inspired American tanka. The author contextualizes this research through an exploration of the arts and poetry as qualitative research.

  20. Capitalizing on Community: the Small College Environment and the Development of Researchers

    NASA Astrophysics Data System (ADS)

    Stoneking, M. R.

    2014-03-01

    Liberal arts colleges constitute an important source of and training ground for future scientists. At Lawrence University, we take advantage of our small college environment to prepare physics students for research careers by complementing content acquisition with skill development and project experience distributed throughout the curriculum and with co-curricular elements that are tied to our close-knit supportive physics community. Small classes and frequent contact between physics majors and faculty members offer opportunities for regular and detailed feedback on the development of research relevant skills such as laboratory record-keeping, data analysis, electronic circuit design, computational programming, experimental design and modification, and scientific communication. Part of our approach is to balance collaborative group work on small projects (such as Arduino-based electronics projects and optical design challenges) with independent work (on, for example, advanced laboratory experimental extensions and senior capstone projects). Communal spaces and specialized facilities (experimental and computational) and active on-campus research programs attract eager students to the program, establish a community-based atmosphere, provide unique opportunities for the development of research aptitude, and offer opportunities for genuine contribution to a research program. Recently, we have also been encouraging innovativetendencies in physics majors through intentional efforts to develop personal characteristics, encouraging students to become more tolerant of ambiguity, risk-taking, initiative-seeking, and articulate. Indicators of the success of our approach include the roughly ten physics majors who graduate each year and our program's high ranking among institutions whose graduates go on to receive the Ph.D. in physics. Work supported in part by the National Science Foundation.

  1. 77 FR 23228 - Notice of Submission for OMB Review; Small Business Innovation Research (SBIR) Program-Phase II...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... Public Law 106-554, the ``Small Business Reauthorization Act of 2000, H.R. 5667'' enacted on December 21... Notice of Submission for OMB Review; Small Business Innovation Research (SBIR) Program--Phase II--Grant Application Package SUMMARY: This application package invites small business concerns to submit a Phase...

  2. 77 FR 23229 - Submission for OMB Review; Small Business Innovation Research (SBIR) Program-Phase I-Grant...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... Law 106- 554, the ``Small Business Reauthorization Act of ] 2000, H.R. 5667'' enacted on December 21... Submission for OMB Review; Small Business Innovation Research (SBIR) Program--Phase I--Grant Application Package SUMMARY: This application package invites small business concerns to submit a Phase I...

  3. Influence of choice of null network on small-world parameters of structural correlation networks.

    PubMed

    Hosseini, S M Hadi; Kesler, Shelli R

    2013-01-01

    In recent years, coordinated variations in brain morphology (e.g., volume, thickness) have been employed as a measure of structural association between brain regions to infer large-scale structural correlation networks. Recent evidence suggests that brain networks constructed in this manner are inherently more clustered than random networks of the same size and degree. Thus, null networks constructed by randomizing topology are not a good choice for benchmarking small-world parameters of these networks. In the present report, we investigated the influence of choice of null networks on small-world parameters of gray matter correlation networks in healthy individuals and survivors of acute lymphoblastic leukemia. Three types of null networks were studied: 1) networks constructed by topology randomization (TOP), 2) networks matched to the distributional properties of the observed covariance matrix (HQS), and 3) networks generated from correlation of randomized input data (COR). The results revealed that the choice of null network not only influences the estimated small-world parameters, it also influences the results of between-group differences in small-world parameters. In addition, at higher network densities, the choice of null network influences the direction of group differences in network measures. Our data suggest that the choice of null network is quite crucial for interpretation of group differences in small-world parameters of structural correlation networks. We argue that none of the available null models is perfect for estimation of small-world parameters for correlation networks and the relative strengths and weaknesses of the selected model should be carefully considered with respect to obtained network measures.

  4. Education, Training and Employment in Small-Scale Enterprises: Three Industries in Sao Paulo, Brazil. IIEP Research Report No. 63.

    ERIC Educational Resources Information Center

    Leite, Elenice M.; Caillods, Francoise

    Despite the prophecies forecasting their probable disappearance or annihilation, small-scale enterprises have persisted in the Brazilian industrial structure since 1950. To account for the survival of small firms in Brazil, specifically in the state of Sao Paulo, a study examined 100 small firms in three industrial sectors: clothing, mechanical…

  5. Examining the Effects of Text Genre and Structure on Fourth-and Fifth-Grade Students' High-Level Comprehension as Evidenced in Small-Group Discussions

    ERIC Educational Resources Information Center

    Li, Mengyi; Murphy, P. Karen; Firetto, Carla M.

    2014-01-01

    Although there is a rich literature on the role of text genre and structure on students' literal comprehension, more research is needed regarding the role of these text features on students' high-level comprehension as evidenced in their small-group discussions. As such, the present study examined the effects of text genre (i.e., narrative and…

  6. Small-angle Scattering Study of Mesoscopic Structures in Charged Gel and Their Evolution in Dehydration

    SciTech Connect

    Sugiyama, M.; Annaka, M.; Hara, K.; Vigild, M. E.; Wignall, George D

    2003-01-01

    Mesoscopic structures, with length scales {approx}10{sup 2} {angstrom}, were investigated by small-angle X-ray and neutron scattering (SAXS and SANS) in several N-isopropylacrylamide-sodium acrylate (NIPA-SA) copolymeric hydrogels with varying [NIPA]/[SA] ratios and water contents. The SAXS experiments reveal that, depending upon the [NIPA]/[SA] ratio, the dehydrated NIPA-SA gel shows two mesoscopic structures: one consists of randomly distributed SA-rich islands in NIPA matrix, while the other is a microphase-separated structure, composed of NIPA-rich and SA-rich domains. In addition, the SANS experiments reveal the mesoscopic structural features during the dehydration process. As the concentration of the network polymers increases, NIPA-rich and water-rich domains segregate in the gel. Then, an electrostatic interaction between the segregated domains induces a microphase-separated structure in the limit of the dehydrated NIPA-SA gel.

  7. Small angle neutron scattering study to determine the structure of high strength hydrogels.

    NASA Astrophysics Data System (ADS)

    Tominaga, Taiki; Tirumala, Vijay R.; Lin, Eric K.; Wu, Wen-Li; Gong, Jian Ping; Furukawa, Hidemitsu; Osada, Yoshihito

    2006-03-01

    Hydrogels are swollen polymer networks containing more than 90% water. Most hydrogels, however, are mechanically too weak to be used as load bearing devices. Gong et al. have overcome this problem by synthesizing hydrogels with a double network (DN) structure. Modifying the polyelectrolyte network structure by polymerization of high molecular weight uncharged polymer in situ, resulted in orders of magnitude increase in their load bearing ability. Despite 90% water, these tough gels exhibit a fracture stress of 170 kg/cm^2, similar to that of articular cartilage found in the bone-joints of human body. In this work, we determined the structure of DN-gels using small angle neutron scattering. Structural origins for high toughness found in DN-gels were then examined by comparing the structure of DN-gels with that of pure polyelectrolyte network and polyacrylamide solution.

  8. Technical Note: Harmonizing met-ocean model data via standard web services within small research groups

    USGS Publications Warehouse

    Signell, Richard; Camossi, E.

    2016-01-01

    Work over the last decade has resulted in standardised web services and tools that can significantly improve the efficiency and effectiveness of working with meteorological and ocean model data. While many operational modelling centres have enabled query and access to data via common web services, most small research groups have not. The penetration of this approach into the research community, where IT resources are limited, can be dramatically improved by (1) making it simple for providers to enable web service access to existing output files; (2) using free technologies that are easy to deploy and configure; and (3) providing standardised, service-based tools that work in existing research environments. We present a simple, local brokering approach that lets modellers continue to use their existing files and tools, while serving virtual data sets that can be used with standardised tools. The goal of this paper is to convince modellers that a standardised framework is not only useful but can be implemented with modest effort using free software components. We use NetCDF Markup language for data aggregation and standardisation, the THREDDS Data Server for data delivery, pycsw for data search, NCTOOLBOX (MATLAB®) and Iris (Python) for data access, and Open Geospatial Consortium Web Map Service for data preview. We illustrate the effectiveness of this approach with two use cases involving small research modelling groups at NATO and USGS.

  9. Technical note: Harmonising metocean model data via standard web services within small research groups

    NASA Astrophysics Data System (ADS)

    Signell, Richard P.; Camossi, Elena

    2016-05-01

    Work over the last decade has resulted in standardised web services and tools that can significantly improve the efficiency and effectiveness of working with meteorological and ocean model data. While many operational modelling centres have enabled query and access to data via common web services, most small research groups have not. The penetration of this approach into the research community, where IT resources are limited, can be dramatically improved by (1) making it simple for providers to enable web service access to existing output files; (2) using free technologies that are easy to deploy and configure; and (3) providing standardised, service-based tools that work in existing research environments. We present a simple, local brokering approach that lets modellers continue to use their existing files and tools, while serving virtual data sets that can be used with standardised tools. The goal of this paper is to convince modellers that a standardised framework is not only useful but can be implemented with modest effort using free software components. We use NetCDF Markup language for data aggregation and standardisation, the THREDDS Data Server for data delivery, pycsw for data search, NCTOOLBOX (MATLAB®) and Iris (Python) for data access, and Open Geospatial Consortium Web Map Service for data preview. We illustrate the effectiveness of this approach with two use cases involving small research modelling groups at NATO and USGS.

  10. Technical note: Harmonizing met-ocean model data via standard web services within small research groups

    NASA Astrophysics Data System (ADS)

    Signell, R. P.; Camossi, E.

    2015-11-01

    Work over the last decade has resulted in standardized web-services and tools that can significantly improve the efficiency and effectiveness of working with meteorological and ocean model data. While many operational modelling centres have enabled query and access to data via common web services, most small research groups have not. The penetration of this approach into the research community, where IT resources are limited, can be dramatically improved by: (1) making it simple for providers to enable web service access to existing output files; (2) using technology that is free, and that is easy to deploy and configure; and (3) providing tools to communicate with web services that work in existing research environments. We present a simple, local brokering approach that lets modelers continue producing custom data, but virtually aggregates and standardizes the data using NetCDF Markup Language. The THREDDS Data Server is used for data delivery, pycsw for data search, NCTOOLBOX (Matlab®1) and Iris (Python) for data access, and Ocean Geospatial Consortium Web Map Service for data preview. We illustrate the effectiveness of this approach with two use cases involving small research modelling groups at NATO and USGS.1 Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the US Government.

  11. Advanced accelerator and mm-wave structure research at LANL

    SciTech Connect

    Simakov, Evgenya Ivanovna

    2016-06-22

    This document outlines acceleration projects and mm-wave structure research performed at LANL. The motivation for PBG research is described first, with reference to couplers for superconducting accelerators and structures for room-temperature accelerators and W-band TWTs. These topics are then taken up in greater detail: PBG structures and the MIT PBG accelerator; SRF PBG cavities at LANL; X-band PBG cavities at LANL; and W-band PBG TWT at LANL. The presentation concludes by describing other advanced accelerator projects: beam shaping with an Emittance Exchanger, diamond field emitter array cathodes, and additive manufacturing of novel accelerator structures.

  12. Small-angle neutron scattering study of structure and kinetics of temperature-induced protein gelation.

    PubMed

    Chodankar, S; Aswal, V K; Kohlbrecher, J; Vavrin, R; Wagh, A G

    2009-02-01

    The phase diagram, structural evolution, and kinetics of temperature-induced protein gelation of protein Bovine Serum Albumin (BSA) have been studied as a function of solution pH and protein concentration. The protein gelation temperature represents the onset of turbidity in the protein solution, which increases significantly with increasing pH beyond the isoelectric pH of the protein molecule. On the other hand, the gelation temperature decreases with an increase in protein concentration only in the low-protein-concentration regime and shows a small increasing trend at higher protein concentrations. The structural evolution and kinetics of protein gelation have been studied using small-angle neutron scattering. The structure of the protein molecule remains stable up to temperatures very close to the gelation temperature. On increasing the temperature above the gelation temperature, the protein solution exhibits a fractal structure, an indication of gel formation due to aggregation. The fractal dimension of the gel increases with increasing temperature, suggesting an increase in branching between the aggregates, which leads to stronger gels. The increase in both solution pH and protein concentration is found to delay the growth in the fractal structure and its saturation. The kinetics of gelation has been studied using the temperature-jump process of heating. It is found that the structure of the protein gels remains invariant after the heating time ( approximately 1 min), indicating a rapid formation of gel structure within this time. The protein gels prepared through gradual and temperature-jump heating routes do not always show the same structure. In particular, at higher temperatures (e.g., 85 degrees C ), while gradual heating shows a fractal structure, there is collapse of such fractal structure during temperature-jump heating.

  13. Describing an Environment for a Self-Sustaining Technology Transfer Service in a Small Research Budget University: A Case Study

    ERIC Educational Resources Information Center

    Nieb, Sharon Lynn

    2014-01-01

    This single-site qualitative study sought to identify the characteristics that contribute to the self sustainability of technology transfer services at universities with small research budgets through a case study analysis of a small research budget university that has been operating a financially self-sustainable technology transfer service for…

  14. Applying Individual Tree Structure From Lidar to Address the Sensitivity of Allometric Equations to Small Sample Sizes.

    NASA Astrophysics Data System (ADS)

    Duncanson, L.; Dubayah, R.

    2015-12-01

    Lidar remote sensing is widely applied for mapping forest carbon stocks, and technological advances have improved our ability to capture structural details from forests, even resolving individual trees. Despite these advancements, the accuracy of forest aboveground biomass models remains limited by the quality of field estimates of biomass. The accuracies of field estimates are inherently dependent on the accuracy of the allometric equations used to relate measurable attributes to biomass. These equations are calibrated with relatively small samples of often spatially clustered trees. This research focuses on one of many issues involving allometric equations - understanding how sensitive allometric parameters are to the sample sizes used to fit them. We capitalize on recent advances in lidar remote sensing to extract individual tree structural information from six high-resolution airborne lidar datasets in the United States. We remotely measure millions of tree heights and crown radii, and fit allometric equations to the relationship between tree height and radius at a 'population' level, in each site. We then extract samples from our tree database, and build allometries on these smaller samples of trees, with varying sample sizes. We show that for the allometric relationship between tree height and crown radius, small sample sizes produce biased allometric equations that overestimate height for a given crown radius. We extend this analysis using translations from the literature to address potential implications for biomass, showing that site-level biomass may be greatly overestimated when applying allometric equations developed with the typically small sample sizes used in popular allometric equations for biomass.

  15. SmallGEO Structural-Thermal Model (STM) Mechanical Test Campaign

    NASA Astrophysics Data System (ADS)

    Di Carlo, A.; Ruess, F.; Obst, A.; Segelke, H.; Rubio Blanes, A.

    2014-06-01

    SmallGEO is a general-purpose small geostationary satellite platform developed by an industrial team managed by OHB System AG. The consortium includes OHB subsidiaries LuxSpace and OHB Sweden, and RUAG Space. SmallGEO's first use is for Hispasat Advanced Generation 1 (AG1) satellite.RUAG Space was responsible for the development, qualification, production and assembly of the Structure Sub-system as well as the thermal control system.A Structural-Thermal Model (STM) was developed and assembled at RUAG Space premises in Zurich, in parallel with the Protoflight Model (PFM), to qualify the structure and the thermal control system.Between August and December 2012, the STM was subject to testing at European Test Services ETS in Noordwjik to qualify the platform versus all the specified mechanical and thermal environmental loads. Objective of the paper is to describe the phases of the mechanical test campaign, with special focus on the sine burst test, used to substitute the traditional static load tests in qualifying the structure versus the quasi-static launch environment.The challenge was to apply the right accelerations (at least 2.6g lateral and 7.5g axial) to a 3500 kg S/C with a sine vibration at a frequency close enough to resonance to generate the desired amplification and far enough to consider the load application still quasi-static.

  16. Scaling the relative dominance of exogenous drivers in structuring desert small mammal assemblages

    NASA Astrophysics Data System (ADS)

    Rodríguez, Daniela; Ojeda, Ricardo A.

    2015-11-01

    Assemblage patterns could be primarily generated by two types of drivers: exogenous (such as environmental and climatic factors) and endogenous (interactions such as competition, predation, mutualism or herbivory). The most widely accepted hypothesis states that at smaller scales (such as patch scale), interspecific interactions are the major drivers structuring communities, whereas at larger regional scales, factors such as climate, topography and soil act as ecological filters that determine assemblage composition. The general aim of this paper is to compare different exogenous drivers in terms of their relative dominance in structuring desert small mammal communities across a range of spatial scales, from patch to regional, and compare them with previous results on endogenous drivers. Our results show that as spatial scale increases, the explanatory power of exogenous factors also increases, e.g. from 17% at the patch scale (i.e. abundance) to 99% at the regional scale (i.e. diversity). Moreover, environmental drivers vary in type and strength depending on the community estimator across several spatial scales. On the other hand, endogenous drivers such as interspecific interactions are more important at the patch scale, diminishing in importance towards the regional scale. Therefore, the relative importance of exogenous versus endogenous drivers affects small mammal assemblage structure at different spatial scales. Our results fill up a knowledge gap concerning ecological drivers of assemblage structure at intermediate spatial scales for Monte desert small mammals, and highlight the importance of dealing with multi-causal factors in explaining ecological patterns of assemblages.

  17. From small area variations to accountable care organizations: how health services research can inform policy.

    PubMed

    Luft, Harold S

    2012-04-01

    Much of health services research seeks to inform particular policy choices and is best characterized as policy-driven research. The reverse, research-driven policy, occurs when studies alter how people perceive reality, which eventually leads to new policy. An example of the latter is nearly four decades of work by John Wennberg and colleagues. Observing variations in practice across small geographic areas led to the notion that some care is preference sensitive, whereas other care is supply constrained. For the former, patient, rather than physician, preferences should be honored, after acquiring and effectively communicating the best available information on the benefits and risks of treatment options. Finding that areas with high use of services have no better quality or outcomes than do areas with lower use led to the notion of accountable care organizations (ACOs). Eventually, both patient engagement and ACOs were written into the Affordable Care Act of 2010.

  18. The Overlap of Small Molecule and Protein Binding Sites within Families of Protein Structures

    PubMed Central

    Davis, Fred P.; Sali, Andrej

    2010-01-01

    Protein–protein interactions are challenging targets for modulation by small molecules. Here, we propose an approach that harnesses the increasing structural coverage of protein complexes to identify small molecules that may target protein interactions. Specifically, we identify ligand and protein binding sites that overlap upon alignment of homologous proteins. Of the 2,619 protein structure families observed to bind proteins, 1,028 also bind small molecules (250–1000 Da), and 197 exhibit a statistically significant (p<0.01) overlap between ligand and protein binding positions. These “bi-functional positions”, which bind both ligands and proteins, are particularly enriched in tyrosine and tryptophan residues, similar to “energetic hotspots” described previously, and are significantly less conserved than mono-functional and solvent exposed positions. Homology transfer identifies ligands whose binding sites overlap at least 20% of the protein interface for 35% of domain–domain and 45% of domain–peptide mediated interactions. The analysis recovered known small-molecule modulators of protein interactions as well as predicted new interaction targets based on the sequence similarity of ligand binding sites. We illustrate the predictive utility of the method by suggesting structural mechanisms for the effects of sanglifehrin A on HIV virion production, bepridil on the cellular entry of anthrax edema factor, and fusicoccin on vertebrate developmental pathways. The results, available at http://pibase.janelia.org, represent a comprehensive collection of structurally characterized modulators of protein interactions, and suggest that homologous structures are a useful resource for the rational design of interaction modulators. PMID:20140189

  19. Nuclear structure research. Annual progress report

    SciTech Connect

    Wood, J.L.

    1996-12-31

    The most significant development this year has been the realization that EO transition strength is a fundamental manifestation of nuclear mean-square charge radius differences. Thus, EO transitions provide a fundamental signature for shape coexistence in nuclei. In this sense, EO transitions are second only to E2 transitions for signaling (quadrupole) shapes in nuclei and do so when shape differences occur. A major effort has been devoted to the review of EO transitions in nuclei. Experiments have been carried out or are scheduled at: ATLAS/FMA ({alpha} decay of very neutron-deficient Bi isotopes); MSU/NSCL ({beta} decay of {sup 56}Cu); and HRIBF/RMS (commissioning of tape collector, internal conversion/internal-pair spectrometer; {beta} decay of {sup 58}Cu). A considerable effort has been devoted to planning the nuclear structure physics that will be pursued using HRIBF. Theoretical investigations have continued in collaboration with Prof. K. Heyde, Prof. D.J. Rowe, Prof. J.O. Rasmussen, and Prof. P.B. Semmes. These studies focus on shape coexistence and particle-core coupling.

  20. Nuclear structure research. Annual progress report

    SciTech Connect

    Wood, J.L.

    1995-07-31

    The most significant development this year has been the realization of a method for estimating EO transition strength in nuclei and the prediction that the de-excitation (draining) of superdeformed bands must take place, at least in some cases, by strong EO transitions. A considerable effort has been devoted to planning the nuclear structure physics that will be pursued using the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge. A significant effort has been devoted to HRIBF target development. This is a critical component of the HRIBF project. Exhaustive literature searches have been made for a variety of target materials with emphasis on thermodynamic properties. Vapor pressure measurements have been carried out. Experimental data sets for radioactive decays in the very neutron-deficient Pr-Eu and Ir-Tl regions have been under analysis. These decay schemes constitute parts of student Ph.D. theses. These studies are aimed at elucidating the onset of deformation in the Pr-Sm region and the characteristics of shape coexistence in the Ir-Bi region. Further experiments on shape coexistence in the neutron-deficient Ir-Bi region are planned using {alpha} decay studies at the FMA at ATLAS. The first experiment is scheduled for later this year.

  1. ALEPH: Israel's Research Library Network: Background, Evolution, and Implications for Networking in a Small Country.

    ERIC Educational Resources Information Center

    Lazinger, Susan S.

    1991-01-01

    Describes ALEPH, the research library network in Israel, and analyzes the strengths and weaknesses of its decentralized structure. Highlights include comparisons between RLIN and ALEPH; centralized versus decentralized networks; the format of ALEPH; authority control in ALEPH; and non-Roman scripts in both networks. (16 references) (LRW)

  2. Funding and Strategic Alignment Guidance for Infusing Small Business Innovation Research Technology Into Science Mission Directorate Projects at Glenn Research Center for 2015

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.; Steele, Gynelle C.

    2016-01-01

    This report is intended to help NASA program and project managers incorporate Glenn ResearchCenter Small Business Innovation Research/Small Business Technology Transfer (SBIR)/(STTR)technologies into NASA Science Mission Directorate (SMD) programs/projects. Other Government and commercial project managers can also find this useful.

  3. Funding and Strategic Alignment Guidance for Infusing Small Business Innovation Research Technology Into Aeronautics Research Mission Directorate Programs and Projects for 2015

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.; Steele, Gynelle C.

    2016-01-01

    This report is intended to help NASA program and project managers incorporate Small Business Innovation Research/Small Business Technology Transfer (SBIR)/(STTR) technologies into NASA Aeronautics Research Mission Directorate (ARMD) projects. Other Government and commercial projects managers can also find this useful.

  4. YM500v3: a database for small RNA sequencing in human cancer research

    PubMed Central

    Chung, I-Fang; Chang, Shing-Jyh; Chen, Chen-Yang; Liu, Shu-Hsuan; Li, Chia-Yang; Chan, Chia-Hao; Shih, Chuan-Chi; Cheng, Wei-Chung

    2017-01-01

    We previously presented the YM500 database, which contains >8000 small RNA sequencing (smRNA-seq) data sets and integrated analysis results for various cancer miRNome studies. In the updated YM500v3 database (http://ngs.ym.edu.tw/ym500/) presented herein, we not only focus on miRNAs but also on other functional small non-coding RNAs (sncRNAs), such as PIWI-interacting RNAs (piRNAs), tRNA-derived fragments (tRFs), small nuclear RNAs (snRNAs) and small nucleolar RNAs (snoRNAs). There is growing knowledge of the role of sncRNAs in gene regulation and tumorigenesis. We have also incorporated >10 000 cancer-related RNA-seq and >3000 more smRNA-seq data sets into the YM500v3 database. Furthermore, there are two main new sections, ‘Survival' and ‘Cancer', in this updated version. The ‘Survival’ section provides the survival analysis results in all cancer types or in a user-defined group of samples for a specific sncRNA. The ‘Cancer’ section provides the results of differential expression analyses, miRNA–gene interactions and cancer miRNA-related pathways. In the ‘Expression’ section, sncRNA expression profiles across cancer and sample types are newly provided. Cancer-related sncRNAs hold potential for both biotech applications and basic research. PMID:27899625

  5. Narrative health research: exploring big and small stories as analytical tools.

    PubMed

    Sools, Anneke

    2013-01-01

    In qualitative health research many researchers use a narrative approach to study lay health concepts and experiences. In this article, I explore the theoretical linkages between the concepts narrative and health, which are used in a variety of ways. The article builds on previous work that conceptualizes health as a multidimensional, positive, dynamic and morally dilemmatic yet meaningful practice. I compare big and small stories as analytical tools to explore what narrative has to offer to address, nuance and complicate five challenges in narrative health research: (1) the interplay between health and other life issues; (2) the taken-for-granted yet rare character of the experience of good health; (3) coherence or incoherence as norms for good health; (4) temporal issues; (5) health as moral practice. In this article, I do not present research findings per se; rather, I use two interview excerpts for methodological and theoretical reflections. These interview excerpts are derived from a health promotion study in the Netherlands, which was partly based on peer-to-peer interviews. I conclude with a proposal to advance narrative health research by sensitizing researchers to different usages of both narrative and health, and the interrelationship(s) between the two.

  6. Small molecule solution-processed bulk heterojunction solar cells with inverted structure using porphyrin donor

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takaki; Hatano, Junichi; Nakagawa, Takafumi; Yamaguchi, Shigeru; Matsuo, Yutaka

    2013-01-01

    Utilizing tetraethynyl porphyrin derivative (TE-Por) as a small molecule donor material, we fabricated a small molecule solution-processed bulk heterojunction (BHJ) solar cell with inverted structure, which exhibited 1.6% power conversion efficiency (JSC (short-circuit current) = 4.6 mA/cm2, VOC (open-circuit voltage) = 0.90 V, and FF (fill factor) = 0.39) in the device configuration indium tin oxide/TiOx (titanium sub-oxide)/[6,6]-phenyl-C61-butyric acid methyl ester:TE-Por (5:1)/MoOx (molybdenum sub-oxide)/Au under AM1.5 G illumination at 100 mW/cm2. Without encapsulation, the small molecule solution-processed inverted BHJ solar cell also showed remarkable durability to air, where it kept over 73% of its initial power conversion efficiency after storage for 28 days under ambient atmosphere in the dark.

  7. A High-Throughput Processor for Flight Control Research Using Small UAVs

    NASA Technical Reports Server (NTRS)

    Klenke, Robert H.; Sleeman, W. C., IV; Motter, Mark A.

    2006-01-01

    There are numerous autopilot systems that are commercially available for small (<100 lbs) UAVs. However, they all share several key disadvantages for conducting aerodynamic research, chief amongst which is the fact that most utilize older, slower, 8- or 16-bit microcontroller technologies. This paper describes the development and testing of a flight control system (FCS) for small UAV s based on a modern, high throughput, embedded processor. In addition, this FCS platform contains user-configurable hardware resources in the form of a Field Programmable Gate Array (FPGA) that can be used to implement custom, application-specific hardware. This hardware can be used to off-load routine tasks such as sensor data collection, from the FCS processor thereby further increasing the computational throughput of the system.

  8. Reconstruction of the inner structure of small scale mining waste dumps by combining GPR and ERTdata.

    NASA Astrophysics Data System (ADS)

    Kniess, Rudolf; Martin, Tina

    2015-04-01

    Two abandoned small waste dumps in the west of the Harz mountains (Germany) were analysed using ground penetrating radar (GPR) and electrical resistivity tomography (ERT). Aim of the project (ROBEHA, funded by the German Federal Ministry of Education and Research (033R105)) is the assessment of the recycling potential of the mining residues taking into account environmental risks of reworking the dump site. One task of the geophysical prospection is the investigation of the inner structure of the mining dump. This is important for the estimation of the approximate volume of potentially reusable mining deposits within the waste dump. The two investigated dump sites are different in age and therefore differ in their structure. The older residues (< 1930) consist of ore processing waste from density separation (stamp mill sand). The younger dump site descends from comprises slag dump waste. The layer of fine grained residues at the first dump site is less than 6 m thick and the slag layer is less than 2 m thick. Both sites are partially overlain by forest or grassland vegetation and characterized by topographical irregularities. Due to the inhomogeneity of the sites we applied electrical resistivity tomography (ERT) and ground penetrating radar (GPR) for detailed investigation. Using ERT we could distinguish various layers within the mining dumps. The resistivities of the dumped material differ from the bedrock resistivities at both sites. The GPR measurements show near surface layer boundaries down to 3 - 4 m. In consecutive campaigns 100 MHz and 200 MHz antennas were used. The GPR results (layer boundaries) were included into the ERT inversion algorithm to enable more precise and stable resistivity models. This needs some special preprocessing steps. The 3D-Position of every electrode from ERT measurement and the GPR antenna position on the surface require an accuracy of less than 1cm. At some points, the layer boundaries and radar wave velocities can be calibrated

  9. Eukaryote-specific extensions in ribosomal proteins of the small subunit: Structure and function

    PubMed Central

    Ghosh, Arnab; Komar, Anton A

    2015-01-01

    High-resolution structures of yeast ribosomes have improved our understanding of the architecture and organization of eukaryotic rRNA and proteins, as well as eukaryote-specific extensions present in some conserved ribosomal proteins. Despite this progress, assignment of specific functions to individual proteins and/or eukaryote-specific protein extensions remains challenging. It has been suggested that eukaryote-specific extensions of conserved proteins from the small ribosomal subunit may facilitate eukaryote-specific reactions in the initiation phase of protein synthesis. This review summarizes emerging data describing the structural and functional significance of eukaryote-specific extensions of conserved small ribosomal subunit proteins, particularly their possible roles in recruitment and spatial organization of eukaryote-specific initiation factors. PMID:26779416

  10. Classical chaos and the sensitivity of the acoustic field to small-scale ocean structure

    NASA Astrophysics Data System (ADS)

    Palmer, D. R.; Georges, T. M.; Jones, R. M.

    1991-04-01

    Ray theory is usually the basis of data inversion schemes for acoustic remote sensing of the ocean. Chaotic ray paths are expected to be present whenever the ocean environment possesses small-scale, range-dependent structure. We are studying the implications of their presence for data inversion schemes. Using numerical simulations we consider ray-path characteristics for acoustic remote sensing of the Florida Current. We find small-scale bathymetric structure results in chaotic ray paths and an exponential proliferation of eigenrays. As a result, for each feature in the time-of-arrival pattern, there is associated not a single eigenray but a group, thereby limiting the spatial resolution of a remote sensing system.

  11. Structural investigation of amylose complexes with small ligands: helical conformation, crystalline structure and thermostability.

    PubMed

    Le Bail, P; Rondeau, C; Buléon, A

    2005-03-01

    Crystalline amylose complexes were prepared with decanal, 1-butanol, menthone and alpha-naphtol. Their crystalline structure and the related helical conformation, determined by wide angle X-ray diffraction (WAXD) and 13C CPMAS solid state NMR, were assigned to V6I, V6II, V6III and V8 types, respectively. It was possible to propose some hypotheses on the possible nature of interactions and especially intra-/inter-helical inclusion. Some shifts in the NMR C1 carbon signals were attributed to the presence of ligand in specific sites inside the structure for a same type of V6 helical conformation. Moreover, the crystallinity and polymorphic changes induced by desorption/rehydration were studied. A general increase of the carbon resonances sharpness upon rehydration has been observed, but also a V6II-V6I transition when decreasing the water content. Differential scanning calorimetry (DSC) experiments were also performed to approach the thermostability of the four types of complex and also the way they form again after melting/cooling sequences.

  12. Development of computational small animal models and their applications in preclinical imaging and therapy research.

    PubMed

    Xie, Tianwu; Zaidi, Habib

    2016-01-01

    The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal models have been reported in the literature and used as surrogates to characterize the anatomy of actual animals for the simulation of preclinical studies involving the use of bioluminescence tomography, fluorescence molecular tomography, positron emission tomography, single-photon emission computed tomography, microcomputed tomography, magnetic resonance imaging, and optical imaging. Other applications include electromagnetic field simulation, ionizing and nonionizing radiation dosimetry, and the development and evaluation of new methodologies for multimodality image coregistration, segmentation, and reconstruction of small animal images. This paper provides a comprehensive review of the history and fundamental technologies used for the development of computational small animal models with a particular focus on their application in preclinical imaging as well as nonionizing and ionizing radiation dosimetry calculations. An overview of the overall process involved in the design of these models, including the fundamental elements used for the construction of different types of computational models, the identification of original anatomical data, the simulation tools used for solving various computational problems, and the applications of computational animal models in preclinical research. The authors also analyze the characteristics of categories of computational models (stylized, voxel-based, and boundary representation) and discuss the technical challenges faced at the present time as well as research needs in the future.

  13. Development of computational small animal models and their applications in preclinical imaging and therapy research

    SciTech Connect

    Xie, Tianwu; Zaidi, Habib

    2016-01-15

    The development of multimodality preclinical imaging techniques and the rapid growth of realistic computer simulation tools have promoted the construction and application of computational laboratory animal models in preclinical research. Since the early 1990s, over 120 realistic computational animal models have been reported in the literature and used as surrogates to characterize the anatomy of actual animals for the simulation of preclinical studies involving the use of bioluminescence tomography, fluorescence molecular tomography, positron emission tomography, single-photon emission computed tomography, microcomputed tomography, magnetic resonance imaging, and optical imaging. Other applications include electromagnetic field simulation, ionizing and nonionizing radiation dosimetry, and the development and evaluation of new methodologies for multimodality image coregistration, segmentation, and reconstruction of small animal images. This paper provides a comprehensive review of the history and fundamental technologies used for the development of computational small animal models with a particular focus on their application in preclinical imaging as well as nonionizing and ionizing radiation dosimetry calculations. An overview of the overall process involved in the design of these models, including the fundamental elements used for the construction of different types of computational models, the identification of original anatomical data, the simulation tools used for solving various computational problems, and the applications of computational animal models in preclinical research. The authors also analyze the characteristics of categories of computational models (stylized, voxel-based, and boundary representation) and discuss the technical challenges faced at the present time as well as research needs in the future.

  14. GEFs: structural basis for their activation of small GTP-binding proteins.

    PubMed

    Cherfils, J; Chardin, P

    1999-08-01

    Small GTP-binding proteins of the Ras superfamily function as molecular switches in fundamental events such as signal transduction, cytoskeleton dynamics and intracellular trafficking. Guanine-nucleotide-exchange factors (GEFs) positively regulate these GTP-binding proteins in response to a variety of signals. GEFs catalyze the dissociation of GDP from the inactive GTP-binding proteins. GTP can then bind and induce structural changes that allow interaction with effectors. Representative structures of four main classes of exchange factors have been described recently and, in two cases, structures of the GTP-binding protein-GEF complex have been solved. These structures, together with biochemical studies, have allowed a deeper understanding of the mechanisms of activation of Ras-like GTP-binding proteins and suggested how they might represent targets for therapeutic intervention.

  15. Solution structures of calcium regulating proteins: A small-angle scattering study

    SciTech Connect

    Trewhella, J.; Heidorn, D.B.; Seeger, P.A.

    1987-11-01

    Small-angle X-ray scattering (SAXS) experiments have shown that the solution structures of two calcium-binding regulatory proteins, calmodulin and troponin C, are significantly different from their crystal structure forms. The structural differences occur in a region of calmodulin that is thought to bind to target enzymes;the calmodulin-enzyme complex is an initiator for many important biochemical processes. Calcium binding to calmodulin induces a conformational change that is a prerequisite for calmodulin binding to a target enzyme. SAXS data can characterize this conformational change and give insight into the mechanism of enzyme binding. Neutron resonance scattering promises to determine accurately the distances between calcium binding sites, thus providing important constraints on the structure of calmodulin in solution. 24 refs., 5 figs., 1 tab.

  16. Structure and Genome Organization of Cherry Virus A (Capillovirus, Betaflexiviridae) from China Using Small RNA Sequencing

    PubMed Central

    Wang, Jiawei; Zhai, Ying; Liu, Weizhen; Dhingra, Amit

    2016-01-01

    Cherry virus A (CVA) (Capillovirus, Betaflexiviridae) is widely present in cherry-growing areas. We obtained the complete genome of a CVA isolate (CVA-TA) using small RNA deep sequencing, followed by overlapping reverse transcription-PCR (RT-PCR) and rapid amplification of cDNA ends (RACE). The newly identified 5′-untranslated region (5′-UTR) from CVA-TA may form additional hairpin and loop structures to stabilize the CVA genome. PMID:27174277

  17. The dynamic structure of a flat small intestinal mucosa studied on the explanted rat jejunum.

    PubMed

    Loehry, C A; Grace, R

    1974-04-01

    Small pieces of jejunum with an intact blood supply were explanted to the anterior abdominal wall in rats. Six weeks after explantation the mucosa appeared totally flat in many areas, both histologically and under the dissecting microscope. The structure of the flattened mucosa was shown to be identical to that in coeliac disease with hypertrophied intervillous ridges. A dynamic study with tritium-labelled thymidine demonstrated a considerably increased turnover in the flat mucosa with some disorganization of cell production and migration.

  18. Study of structural irregularities of smectite clay systems by small-angle neutron scattering and adsorption

    NASA Astrophysics Data System (ADS)

    De Stefanis, A.; Tomlinson, A. A. G.; Steriotis, Th. A.; Charalambopoulou, G. Ch.; Keiderling, U.

    2007-04-01

    Small angle neutron scattering (SANS) and its contrast-matching variant are employed in order to determine structural properties (inter-pillar distances and mass/surface fractal dimensions of the clay layers and pillars) of a series of smectite natural clays (montmorillonite, beidellite, and bentonite) and their pillared and pillared/ion-exchanged analogues. Moreover, a comparative analysis with the adsorption data is carried out on the basis of a systematic study of the structural changes induced by a particular treatment or modification (e.g. pillaring) of the clay systems.

  19. SBDN: an information portal on small bodies and interplanetary dust inside the Europlanet Research Infrastructure

    NASA Astrophysics Data System (ADS)

    Turrini, Diego; de Sanctis, Maria Cristina; Carraro, Francesco; Fonte, Sergio; Giacomini, Livia; Politi, Romolo

    In the framework of the Sixth Framework Programme (FP6) for Research and Technological Development of the European Community, the Europlanet project started the Integrated and Distributed Information Service (IDIS) initiative. The goal of this initiative was to "...offer to the planetary science community a common and user-friendly access to the data and infor-mation produced by the various types of research activities: earth-based observations, space observations, modelling and theory, laboratory experiments...". Four scientific nodes, repre-sentative of a significant fraction of the scientific themes covered by planetary sciences, were created: the Interiors and Surfaces node, the Atmospheres node, the Plasma node and the Small Bodies and Dust node. The original Europlanet program evolved into the Europlanet Research Infrastructure project, funded by the Seventh Framework Programme (FP7) for Research and Technological Development, and the IDIS initiative has been renewed with the addiction of a new scientific node, the Planetary Dynamics node. Here we present the Small Bodies and Dust node (SBDN) and the services it already provides to the scientific community, i.e. a searchable database of resources related to its thematic domains, an online and searchable cat-alogue of emission lines observed in the visible spectrum of comet 153P/2002 C1 Ikeya-Zhang supplemented by a visualization facility, a set of models of the simulated evolution of comet 67P/Churyumov-Gerasimenko with a particular focus on the effects of the distribution of dust and a information system on meteors through the Virtual Meteor Observatory. We will also introduce the new services that will be implemented and made available in the course of the Europlanet Research Infrastructure project.

  20. Burrowing by small polychaetes - mechanics, behavior and muscle structure of Capitella sp.

    PubMed

    Grill, Susann; Dorgan, Kelly M

    2015-05-15

    Worms of different sizes extend burrows through muddy sediments by fracture, applying dorso-ventral forces that are amplified at the crack tip. Smaller worms displace sediments less than larger worms and therefore are limited in how much force they can apply to burrow walls. We hypothesized that small worms would exhibit a transition in burrowing mechanics, specifically a lower limit in body size for the ability to burrow by fracture, corresponding with an ontogenetic transition in muscle morphology. Kinematics of burrowing in a mud analog, external morphology and muscle arrangement were examined in juveniles and adults of the small polychaete Capitella sp. We found that it moves by peristalsis, and no obvious differences were observed among worms of different sizes; even very small juveniles were able to burrow through a clear mud analog by fracture. Interestingly, we found that in addition to longitudinal and circular muscles needed for peristaltic movements, left- and right-handed helical muscles wrap around the thorax of worms of all sizes. We suggest that in small worms helical muscles may function to supplement forces generated by longitudinal muscles and to maintain hydrostatic pressure, enabling higher forces to be exerted on the crack wall. Further research is needed, however, to determine whether surficial sediments inhabited by small worms fail by fracture or plastically deform under forces of the magnitudes applied by Capitella sp.

  1. Structure parameters of synaptic vesicles quantified by small-angle x-ray scattering.

    PubMed

    Castorph, Simon; Riedel, Dietmar; Arleth, Lise; Sztucki, Michael; Jahn, Reinhard; Holt, Matthew; Salditt, Tim

    2010-04-07

    Synaptic vesicles (SVs) are small, membrane-bound organelles that are found in the synaptic terminal of neurons, and which are crucial in neurotransmission. After a rise in internal [Ca(2+)] during neuronal stimulation, SVs fuse with the plasma membrane releasing their neurotransmitter content, which then signals neighboring neurons. SVs are subsequently recycled and refilled with neurotransmitter for further rounds of release. Recently, tremendous progress has been made in elucidating the molecular composition of SVs, as well as putative protein-protein interactions. However, what is lacking is an empirical description of SV structure at the supramolecular level-which is necessary to enable us to fully understand the processes of membrane fusion, retrieval, and recycling. Using small-angle x-ray scattering, we have directly investigated the size and structure of purified SVs. From this information, we deduced detailed size and density parameters for the protein layers responsible for SV function, as well as information about the lipid bilayer. To achieve a convincing model fit, a laterally anisotropic structure for the protein shell is needed, as a rotationally symmetric density profile does not explain the data. Not only does our model confirm many of the preexisting ideas concerning SV structure, but also for the first time, to our knowledge, it indicates structural refinements, such as the presence of protein microdomains.

  2. Research Articles in Applied Linguistics: Structures from a Functional Perspective

    ERIC Educational Resources Information Center

    Ruiying, Yang; Allison, Desmond

    2004-01-01

    This paper presents the main lines of a genre analysis of the macro-structures of research articles (RAs) in applied linguistics, an area that deserves more attention both for pedagogic and research reasons. The analysis is based upon a detailed study of a corpus of 40 RAs, selected as random sets of 10 drawn from four leading journals in the…

  3. Bridging Emotion Research: From Biology to Social Structure

    ERIC Educational Resources Information Center

    Rogers, Kimberly B.; Kavanagh, Liam

    2010-01-01

    Emotion research demonstrates that problems of theoretical interest or practical significance are not divided neatly along disciplinary boundaries. Researchers acknowledge both organic and social underpinnings of emotion, but the intersections between biological and structural processes can be difficult to negotiate. In this article, the authors…

  4. Structural dynamics branch research and accomplishments to FY 1992

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles

    1992-01-01

    This publication contains a collection of fiscal year 1992 research highlights from the Structural Dynamics Branch at NASA LeRC. Highlights from the branch's major work areas--Aeroelasticity, Vibration Control, Dynamic Systems, and Computational Structural Methods are included in the report as well as a listing of the fiscal year 1992 branch publications.

  5. Investigation of the tripoli porous structure by small-angle neutron scattering

    SciTech Connect

    Avdeev, M. V.; Blagoveshchenskii, N. M.; Garamus, V. M.; Novikov, A. G. Puchkov, A. V.

    2011-12-15

    The characteristics of the tripoli porous structure have been investigated by small-angle neutron scattering (SANS). Tripoli is a finely porous sedimentary rock formed by small spherical opal particles. Its main component is aqueous silica SiO{sub 2} {center_dot} nH{sub 2}O (80-90%). Tripoli is widely used in practice as a working medium for sorption filters and in some other commercial and construction technologies. The shape of the experimental SANS curves indicates the presence of small and large pores in tripoli. The small-pore size was estimated to be {approx}100 Angstrom-Sign . The size of large pores turned out to be beyond the range of neutron wave vector transfers Q that are available for the instrument used; however, their size was indirectly estimated to be {approx}(2000-2500) Angstrom-Sign . The pores of both groups behave as surfacetype fractal scatterers with the fractal dimension D {approx} 2.2-2.6. The densities of pores of these two groups differ by approximately three orders of magnitude ({approx}10{sup 16} and {approx}10{sup 13} cm{sup -3} for small and large pores, respectively); the fraction of large pores amounts to 70-80% of the total pore volume. The found pore characteristics (their densities, sizes, and relative volumes) are in satisfactory agreement (when a comparison is possible) with the absorption data.

  6. Structural insights into mechanisms of the small RNA methyltransferase HEN1

    SciTech Connect

    Huang, Ying; Ji, Lijuan; Huang, Qichen; Vassylyev, Dmitry G.; Chen, Xuemei; Ma, Jin-Biao

    2010-02-22

    RNA silencing is a conserved regulatory mechanism in fungi, plants and animals that regulates gene expression and defence against viruses and transgenes. Small silencing RNAs of {approx}20-30 nucleotides and their associated effector proteins, the Argonaute family proteins, are the central components in RNA silencing. A subset of small RNAs, such as microRNAs and small interfering RNAs (siRNAs) in plants, Piwi-interacting RNAs in animals and siRNAs in Drosophila, requires an additional crucial step for their maturation; that is, 2'-O-methylation on the 3' terminal nucleotide. A conserved S-adenosyl-L-methionine-dependent RNA methyltransferase, HUA ENHANCER 1 (HEN1), and its homologues are responsible for this specific modification. Here we report the 3.1 {angstrom} crystal structure of full-length HEN1 from Arabidopsis in complex with a 22-nucleotide small RNA duplex and cofactor product S-adenosyl-L-homocysteine. Highly cooperative recognition of the small RNA substrate by multiple RNA binding domains and the methyltransferase domain in HEN1 measures the length of the RNA duplex and determines the substrate specificity. Metal ion coordination by both 2' and 3' hydroxyls on the 3'-terminal nucleotide and four invariant residues in the active site of the methyltransferase domain suggests a novel Mg{sup 2+}-dependent 2'-O-methylation mechanism.

  7. Small-angle x-ray scattering investigation of the solution structure of troponin C

    SciTech Connect

    Hubbard, S.R.; Hodgson, K.O.; Doniach, S.

    1988-03-25

    X-ray crystallographic studies of troponin C have revealed a novel protein structure consisting of two globular domains, each containing two Ca/sup 2 +/-binding sites, connected via a nine-turn alpha-helix, three turns of which are fully exposed to solvent. Since the crystals were grown at pH approximately 5, it is of interest to determine whether this structure is applicable to the protein in solution under physiological conditions. We have used small-angle x-ray scattering to examine the solution structure of troponin C at pH 6.8 and the effect of Ca/sup 2 +/ on the structure. The scattering data are consistent with an elongated structure in solution with a radius of gyration of approximately 23.0 A, which is quite comparable to that computed for the crystal structure. The experimental scattering profile and the scattering profile computed from the crystal structure coordinates do, however, exhibit differences at the 40-A level. A weak Ca/sup 2 +/-facilitated dimerization of troponin C was observed. The data rule out large Ca/sup 2 +/-induced structural changes, indicating rather that the molecule with Ca/sup 2 +/ bound is only slightly more compact than the Ca/sup 2 +/-free molecule.

  8. Obtaining structural information of small proteins using solid-state nanopores and high-bandwidth measurements

    NASA Astrophysics Data System (ADS)

    Niedzwiecki, David; Lanci, Christopher; Saven, Jeffery; Drndic, Marija

    2015-03-01

    The use of biological nanopores sensors to characterize proteins has proved a fruitful field of study. Solid-state nanopores hold several advantages over their biological counterparts, including the ability to tune pore diameter and their robustness to external conditions. Despite these advantages, the use of solid-state nanopores for protein analysis has proved difficult due to rapid translocation times of proteins and poor signal-to-noise of small peptides. Recently, improvements in high-bandwidth acquisition and in signal-to-noise have made the study of small peptides using solid-state nanopores feasible. Here we report on the detection and characterization of peptides as small as 33 amino-acids in length using sub-10 nm thin silicon nitride nanopores, giving high signal levels, combined with high-bandwidth electronics. In addition we show differentiation between monomers and dimer forms of the GCN-4 p1 leucine zipper, a coil-coil structure, and compare this with the unstructured 33-mer. The differentiation between these two forms demonstrates the possibility of extracting useful structural information from short peptide structures using modern solid-state nanopore systems.

  9. Digestive enzyme expression and epithelial structure of small intestine in neonatal rats after 16 days spaceflight

    NASA Astrophysics Data System (ADS)

    Miyake, M.; Yamasaki, M.; Hazama, A.; Ijiri, K.; Shimizu, T.

    It is important to assure whether digestive system can develop normally in neonates during spaceflight. Because the small intestine changes its function and structure drastically around weaning known as redifferentiation. Lactase expression declines and sucrase increases in small intestine for digestion of solid food before weaning. In this paper, we compared this enzyme transition and structural development of small intestine in neonatal rats after spaceflight. To find digestive genes differentially expressed in fight rats, DNA membrane macroarray was also used. Eight-day old rats were loaded to Space Shuttle Columbia, and housed in the animal facility for 16 days in space (STS-90, Neurolab mission). Two control groups (AGC; asynchronous ground control and VIV; vivarium) against flight group (FLT) were prepared. There was no difference in structure (crypt depth) and cell differentiation of epithelium between FLT and AGC by immunohistochemical analysis. We found that the amount of sucrase mRNA compared to lactase was decreased in FLT by RT-PCR. It reflected the enzyme transition was inhibited. Increase of 5 genes (APO A-I, APO A-IV, ACE, aFABP and aminopeptidase M) and decrease of carboxypeptidase-D were detected in FLT using macroarray. We think nutrition differences (less nourishment and late weaning) during spaceflight may cause inhibition of enzyme transition at least partly. The weightlessness might contribute to the inhibition through behavioral change.

  10. Big Data: the challenge for small research groups in the era of cancer genomics

    PubMed Central

    Noor, Aisyah Mohd; Holmberg, Lars; Gillett, Cheryl; Grigoriadis, Anita

    2015-01-01

    In the past decade, cancer research has seen an increasing trend towards high-throughput techniques and translational approaches. The increasing availability of assays that utilise smaller quantities of source material and produce higher volumes of data output have resulted in the necessity for data storage solutions beyond those previously used. Multifactorial data, both large in sample size and heterogeneous in context, needs to be integrated in a standardised, cost-effective and secure manner. This requires technical solutions and administrative support not normally financially accounted for in small- to moderate-sized research groups. In this review, we highlight the Big Data challenges faced by translational research groups in the precision medicine era; an era in which the genomes of over 75 000 patients will be sequenced by the National Health Service over the next 3 years to advance healthcare. In particular, we have looked at three main themes of data management in relation to cancer research, namely (1) cancer ontology management, (2) IT infrastructures that have been developed to support data management and (3) the unique ethical challenges introduced by utilising Big Data in research. PMID:26492224

  11. Big Data: the challenge for small research groups in the era of cancer genomics.

    PubMed

    Noor, Aisyah Mohd; Holmberg, Lars; Gillett, Cheryl; Grigoriadis, Anita

    2015-11-17

    In the past decade, cancer research has seen an increasing trend towards high-throughput techniques and translational approaches. The increasing availability of assays that utilise smaller quantities of source material and produce higher volumes of data output have resulted in the necessity for data storage solutions beyond those previously used. Multifactorial data, both large in sample size and heterogeneous in context, needs to be integrated in a standardised, cost-effective and secure manner. This requires technical solutions and administrative support not normally financially accounted for in small- to moderate-sized research groups. In this review, we highlight the Big Data challenges faced by translational research groups in the precision medicine era; an era in which the genomes of over 75,000 patients will be sequenced by the National Health Service over the next 3 years to advance healthcare. In particular, we have looked at three main themes of data management in relation to cancer research, namely (1) cancer ontology management, (2) IT infrastructures that have been developed to support data management and (3) the unique ethical challenges introduced by utilising Big Data in research.

  12. Teachers As Researchers: Improving Practice in Rural and Small Schools. Rural, Small Schools Network Information Exchange: Number 11, Fall 1991.

    ERIC Educational Resources Information Center

    Regional Laboratory for Educational Improvement of the Northeast & Islands, Andover, MA.

    This packet includes reprints of journal articles and other information exploring reflective practice and action research among rural educators. The four sections of the packet cover concepts of reflective practice and action research; examples of reflective practice at both the elementary and secondary levels; issues such as encouraging…

  13. Structural biology research at the National Synchroton Light Source

    SciTech Connect

    1996-05-01

    The world`s foremost facility for scientific research using x-rays and ultraviolet and infrared radiation is operated by the national synchrotron Light Source Department. This year alone, a total of 2200 guest researchers performed experiments at the world`s largest source of synchrotron light. Researchers are trying to define the three- dimensional structures of biological macromolecules to create a map of life, a guide for exploring the biological and chemical interactions of the vast variety of molecules found in living organisms. Studies in structural biology may lead to new insights into how biological systems are formed and nourished, how they survive and grow, how they are damaged and die. This document discusses some the the structural biological research done at the National Synchrotron Light Source.

  14. Structure and conformational plasticity of the U6 small nuclear ribonucleoprotein core.

    PubMed

    Montemayor, Eric J; Didychuk, Allison L; Liao, Honghong; Hu, Panzhou; Brow, David A; Butcher, Samuel E

    2017-01-01

    U6 small nuclear RNA (snRNA) is a key component of the active site of the spliceosome, a large ribonucleoprotein complex that catalyzes the splicing of precursor messenger RNA. Prior to its incorporation into the spliceosome, U6 is bound by the protein Prp24, which facilitates unwinding of the U6 internal stem-loop (ISL) so that it can pair with U4 snRNA. A previously reported crystal structure of the `core' of the U6 small nuclear ribonucleoprotein (snRNP) contained an ISL-stabilized A62G mutant of U6 bound to all four RNA-recognition motif (RRM) domains of Prp24 [Montemayor et al. (2014), Nature Struct. Mol. Biol. 21, 544-551]. The structure revealed a novel topology containing interlocked rings of protein and RNA that was not predicted by prior biochemical and genetic data. Here, the crystal structure of the U6 snRNP core with a wild-type ISL is reported. This complex crystallized in a new space group, apparently owing in part to the presence of an intramolecular cross-link in RRM1 that was not observed in the previously reported U6-A62G structure. The structure exhibits the same protein-RNA interface and maintains the unique interlocked topology. However, the orientation of the wild-type ISL is altered relative to the A62G mutant structure, suggesting inherent structural dynamics that may facilitate its pairing with U4. Consistent with their similar architectures in the crystalline state, the wild-type and A62G variants of U6 exhibit similar Prp24-binding affinities and electrophoretic mobilities when analyzed by gel-shift assay.

  15. The dynamic duo: Combining NMR and small angle scattering in structural biology

    PubMed Central

    Hennig, Janosch; Sattler, Michael

    2014-01-01

    Structural biology provides essential information for elucidating molecular mechanisms that underlie biological function. Advances in hardware, sample preparation, experimental methods, and computational approaches now enable structural analysis of protein complexes with increasing complexity that more closely represent biologically entities in the cellular environment. Integrated multidisciplinary approaches are required to overcome limitations of individual methods and take advantage of complementary aspects provided by different structural biology techniques. Although X-ray crystallography remains the method of choice for structural analysis of large complexes, crystallization of flexible systems is often difficult and does typically not provide insights into conformational dynamics present in solution. Nuclear magnetic resonance spectroscopy (NMR) is well-suited to study dynamics at picosecond to second time scales, and to map binding interfaces even of large systems at residue resolution but suffers from poor sensitivity with increasing molecular weight. Small angle scattering (SAS) methods provide low resolution information in solution and can characterize dynamics and conformational equilibria complementary to crystallography and NMR. The combination of NMR, crystallography, and SAS is, thus, very useful for analysis of the structure and conformational dynamics of (large) protein complexes in solution. In high molecular weight systems, where NMR data are often sparse, SAS provides additional structural information and can differentiate between NMR-derived models. Scattering data can also validate the solution conformation of a crystal structure and indicate the presence of conformational equilibria. Here, we review current state-of-the-art approaches for combining NMR, crystallography, and SAS data to characterize protein complexes in solution. PMID:24687405

  16. Structure of the archaeal Cascade subunit Csa5: relating the small subunits of CRISPR effector complexes.

    PubMed

    Reeks, Judith; Graham, Shirley; Anderson, Linzi; Liu, Huanting; White, Malcolm F; Naismith, James H

    2013-05-01

    The Cascade complex for CRISPR-mediated antiviral immunity uses CRISPR RNA (crRNA) to target invading DNA species from mobile elements such as viruses, leading to their destruction. The core of the Cascade effector complex consists of the Cas5 and Cas7 subunits, which are widely conserved in prokaryotes. Cas7 binds crRNA and forms the helical backbone of Cascade. Many archaea encode a version of the Cascade complex (denoted Type I-A) that includes a Csa5 (or small) subunit, which interacts weakly with the core proteins. Here, we report the crystal structure of the Csa5 protein from Sulfolobus solfataricus. Csa5 comprises a conserved α-helical domain with a small insertion consisting of a weakly conserved β-strand domain. In the crystal, the Csa5 monomers have multimerized into infinite helical threads. At each interface is a strictly conserved intersubunit salt bridge, deletion of which disrupts multimerization. Structural analysis indicates a shared evolutionary history among the small subunits of the CRISPR effector complexes. The same α-helical domain is found in the C-terminal domain of Cse2 (from Type I-E Cascade), while the N-terminal domain of Cse2 is found in Cmr5 of the CMR (Type III-B) effector complex. As Cmr5 shares no match with Csa5, two possibilities present themselves: selective domain loss from an ancestral Cse2 to create two new subfamilies or domain fusion of two separate families to create a new Cse2 family. A definitive answer awaits structural studies of further small subunits from other CRISPR effector complexes.

  17. Crystal structure prediction and isostructurality of three small organic halogen compounds.

    PubMed

    Asmadi, Aldi; Kendrick, John; Leusen, Frank J J

    2010-08-14

    A theoretical investigation of the packing stabilities of three small organic halogen compounds is presented based on a crystal structure prediction (CSP) study. Each compound has four identical halogen atoms (fluorine, chlorine, and bromine) and a four-membered ring consisting of carbon and sulfur atoms arranged alternately. Two halogen atoms are attached to each carbon and two oxygen atoms are attached to each sulfur forming SO(2) functional groups. The crystal structures of these compounds have been determined experimentally and show distinct packing arrangements. Utilising the computational approaches implemented in the GRACE software package, each compound is subjected to a full CSP study using a force field specific for each molecule (called the tailor-made force field or TMFF) and a dispersion corrected solid-state density functional method (or DFT(d) method). Energetically feasible crystal structures are generated in all 230 space groups restricted to a single molecule in the crystallographic asymmetric unit (Z' = 1) using the TMFF of each molecule. Next, a selection of structures with low TMFF lattice energies are further refined with the DFT(d) method. The CSP results show that the experimental crystal structures of the molecules containing fluorine and chlorine are well described energetically and geometrically by their TMFFs and the DFT(d) method. Both approaches locate their experimental lattices as the most stable structures. For the molecule containing bromine, a crystal structure corresponding to the force field optimised experimental structure is located as the second structure in the list of force field predicted structures, ranked by calculated lattice energy. Despite the structural similarity of the predicted and experimental structures, close examination of the DFT(d) optimisation results of the experimental structure reveals a slightly lower energy structure than that found by the CSP simulations. Furthermore, minimisation of the force field

  18. Talking Science: The research evidence on the use of small group discussions in science teaching

    NASA Astrophysics Data System (ADS)

    Bennett, Judith; Hogarth, Sylvia; Lubben, Fred; Campbell, Bob; Robinson, Alison

    2010-01-01

    This paper reports the findings of two systematic reviews of the use and effects of small group discussions in high school science teaching. Ninety-four studies were included in an overview (systematic map) of work in the area, and 24 studies formed the basis of the in-depth reviews. The reviews indicate that there is considerable diversity in the topics used to promote small group discussions. They also demonstrate that students often struggle to formulate and express coherent arguments, and demonstrate a low level of engagement with tasks. The reviews suggest that groups function more purposefully, and understanding improves most, when specifically constituted such that differing views are represented, when some form of training is provided for students on effective group work, and when help in structuring discussions is provided in the form of "cues". Single-sex groups function more purposefully than mixed-sex groups, though improvements in understanding are independent of gender composition of groups. Finally, the reviews demonstrate very clearly that, for small group discussions to be effective, teachers and students need to be given explicit teaching in the skills associated with the development of arguments and the characteristics associated with effective group discussions. In addition to the substantive findings, the paper also reports on key features of the methods employed to gather and analyse data. Of particular note are the two contrasting approaches to data analysis, one adopting a grounded theory approach and the other drawing on established methods of discourse analysis.

  19. Review of Recent Researches Related to Lightning to Tall Structures

    NASA Astrophysics Data System (ADS)

    Baba, Yoshihiro

    In this technical note, fundamental characteristics of lightning to tall structures are described, and recent researches related to lightning to tall structures are reviewed. In Section 2, the relationship between the incidence of lightning to a tall structure and the structure height, and that between the incidence of upward lightning initiated from a tall structure and the structure height, both of which were obtained by Eriksson empirically, are shown. Also, winter lightning strikes to tall structures and to wind-turbine-generator towers located on the coastal area of the Sea of Japan are described. In Section 3, characteristics of a current wave propagating along a tall structure hit by lightning are discussed. Also, simplified transmission-line representations for lightning strikes to a tall structure and to flat ground are shown, and dependences of the peak current on the observation height (top or bottom of the structure) and on the current risetime, obtained from the analysis using the simplified representations, are shown. In Section 4, median values of lightning currents measured on tall structures are shown. In Section 5, the electromagnetic field environment in the vicinity of a tall structure hit by lightning is discussed. Also, the far-field enhancement factor and the far-field-to-current conversion factor for lightning strikes to tall structures are shown.

  20. ACEE Composite Structures Technology: Review of selected NASA research on composite materials and structures

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The NASA Aircraft Energy Efficiency (ACEE) Composite Primary Aircraft Structures Program was designed to develop technology for advanced composites in commercial aircraft. Research on composite materials, aircraft structures, and aircraft design is presented herein. The following parameters of composite materials were addressed: residual strength, damage tolerance, toughness, tensile strength, impact resistance, buckling, and noise transmission within composite materials structures.

  1. A tetraphenylethylene core-based 3D structure small molecular acceptor enabling efficient non-fullerene organic solar cells.

    PubMed

    Liu, Yuhang; Mu, Cheng; Jiang, Kui; Zhao, Jingbo; Li, Yunke; Zhang, Lu; Li, Zhengke; Lai, Joshua Yuk Lin; Hu, Huawei; Ma, Tingxuan; Hu, Rongrong; Yu, Demei; Huang, Xuhui; Tang, Ben Zhong; Yan, He

    2015-02-01

    A tetraphenylethylene core-based small molecular acceptor with a unique 3D molecular structure is developed. Bulk-heterojunction blend films with a small feature size (≈20 nm) are obtained, which lead to non-fullerene organic solar cells (OSCs) with 5.5% power conversion efficiency. The work provides a new molecular design approach to efficient non-fullerene OSCs based on 3D-structured small-molecule acceptors.

  2. Evaluation applications of instrument calibration research findings in psychology for very small samples

    NASA Astrophysics Data System (ADS)

    Fisher, W. P., Jr.; Petry, P.

    2016-11-01

    Many published research studies document item calibration invariance across samples using Rasch's probabilistic models for measurement. A new approach to outcomes evaluation for very small samples was employed for two workshop series focused on stress reduction and joyful living conducted for health system employees and caregivers since 2012. Rasch-calibrated self-report instruments measuring depression, anxiety and stress, and the joyful living effects of mindfulness behaviors were identified in peer-reviewed journal articles. Items from one instrument were modified for use with a US population, other items were simplified, and some new items were written. Participants provided ratings of their depression, anxiety and stress, and the effects of their mindfulness behaviors before and after each workshop series. The numbers of participants providing both pre- and post-workshop data were low (16 and 14). Analysis of these small data sets produce results showing that, with some exceptions, the item hierarchies defining the constructs retained the same invariant profiles they had exhibited in the published research (correlations (not disattenuated) range from 0.85 to 0.96). In addition, comparisons of the pre- and post-workshop measures for the three constructs showed substantively and statistically significant changes. Implications for program evaluation comparisons, quality improvement efforts, and the organization of communications concerning outcomes in clinical fields are explored.

  3. Validation of the Small Hot Jet Acoustic Rig for Jet Noise Research

    NASA Technical Reports Server (NTRS)

    Bridges, James; Brown, Clifford A.

    2005-01-01

    The development and acoustic validation of the Small Hot Jet Aeroacoustic Rig (SHJAR) is documented. Originally conceived to support fundamental research in jet noise, the rig has been designed and developed using the best practices of the industry. While validating the rig for acoustic work, a method of characterizing all extraneous rig noise was developed. With this in hand, the researcher can know when the jet data being measured is being contaminated and design the experiment around this limitation. Also considered is the question of uncertainty, where it is shown that there is a fundamental uncertainty of 0.5dB or so to the best experiments, confirmed by repeatability studies. One area not generally accounted for in the uncertainty analysis is the variation which can result from differences in initial condition of the nozzle shear layer. This initial condition was modified and the differences in both flow and sound were documented. The bottom line is that extreme caution must be applied when working on small jet rigs, but that highly accurate results can be made independent of scale.

  4. Probabilistic structural mechanics research for parallel processing computers

    NASA Technical Reports Server (NTRS)

    Sues, Robert H.; Chen, Heh-Chyun; Twisdale, Lawrence A.; Martin, William R.

    1991-01-01

    Aerospace structures and spacecraft are a complex assemblage of structural components that are subjected to a variety of complex, cyclic, and transient loading conditions. Significant modeling uncertainties are present in these structures, in addition to the inherent randomness of material properties and loads. To properly account for these uncertainties in evaluating and assessing the reliability of these components and structures, probabilistic structural mechanics (PSM) procedures must be used. Much research has focused on basic theory development and the development of approximate analytic solution methods in random vibrations and structural reliability. Practical application of PSM methods was hampered by their computationally intense nature. Solution of PSM problems requires repeated analyses of structures that are often large, and exhibit nonlinear and/or dynamic response behavior. These methods are all inherently parallel and ideally suited to implementation on parallel processing computers. New hardware architectures and innovative control software and solution methodologies are needed to make solution of large scale PSM problems practical.

  5. Thresholds in small rivers? Hypotheses developed from fluvial morphological research in western Germany

    NASA Astrophysics Data System (ADS)

    Harnischmacher, Stefan

    2007-12-01

    The objective of this study was the formulation of fluvial morphological regularities for small rivers with a wide range of morphological and geological characteristics in North-Rhine-Westphalia (Germany) based on a statistical research methodology. Such empirical quantitative information on reference conditions is required for the restoration of small rivers in the former highly industrialised Ruhr-Area. Following the approach of some classic empirical works in fluvial morphology of the last century, several natural reference rivers in the entire research area have been observed in order to provide a statistical correlation between independent and dependent morphological variables. Regressions between valley-floor slope, bankfull discharge and stream power on the one hand and several variables describing the longitudinal profile and river planform on the other hand have shown some significant results. The regularities found are a quantitative contribution to the establishment of reference conditions as well as a useful tool for the restoration of small rivers, if the specific properties and values of the underlying random sampling are taken into account. In addition, the relation between stream power and sinuosity shows the likely existence of a threshold: Exceeding a stream power of 100 W/m, the sinuosity decreases after an increase for lower stream power values. Comparable thresholds were found for the relation between stream power and pool depth as well as stream power and step steepness. The thresholds could be explained by a change in the type of energy dissipation, due to different physio-geographical settings in highland rivers within forested v-shaped valleys. Here, large-woody debris seems to increase the channel roughness and possibly replaces the significance of coarse-grained bed material, pool depth and step steepness as contributors to energy dissipation.

  6. Determination of short-circuit current in small tubular structures via cable analysis.

    PubMed

    Haag, K; Knauf, H

    1990-01-01

    Use of cable analysis is a time-consuming maneuver. On the other hand, the advantage of the cable method consists in obtaining the Isc and Rm related to unit area without the explicit measurement of inside radius r of the tubular structure. Obviously, application of the clamping technique requires, in addition, the determination of the surface area. In summary, for small tubular structures, such as the salivary ducts of rats and rabbits, and for human experiments, cable analysis is the method of choice for the Isc determination in vivo as well as in vitro. For larger tubular structures such as the rat colon the Isc should be determined in vivo by the clamping technique described above, whereas the in vitro measurements should be done in an Ussing-type chamber. In the intermediate range of size both in vivo techniques should be applied, in which case one method may serve as a check of the other.

  7. Small-angle x-ray scattering study of polymer structure: Carbosilane dendrimers in hexane solution

    NASA Astrophysics Data System (ADS)

    Shtykova, E. V.; Feigin, L. A.; Volkov, V. V.; Malakhova, Yu. N.; Streltsov, D. R.; Buzin, A. I.; Chvalun, S. N.; Katarzhanova, E. Yu.; Ignatieva, G. M.; Muzafarov, A. M.

    2016-09-01

    The three-dimensional organization of monodisperse hyper-branched macromolecules of regular structure—carbosilane dendrimers of zero, third, and sixth generations—has been studied by small-angle X-ray scattering (SAXS) in solution. The use of modern methods of SAXS data interpretation, including ab initio modeling, has made it possible to determine the internal architecture of the dendrimers in dependence of the generation number and the number of cyclosiloxane end groups (forming the shell of dendritic macromolecules) and show dendrimers to be spherical. The structural results give grounds to consider carbosilane dendrimers promising objects for forming crystals with subsequent structural analysis and determining their structure with high resolution, as well as for designing new materials to be used in various dendrimer-based technological applications.

  8. Structural Analysis of the Flagellar Component Proteins in Solution by Small Angle X-Ray Scattering.

    PubMed

    Lee, Lawrence K

    2017-01-01

    Small angle X-ray scattering is an increasingly utilized method for characterizing the shape and structural properties of proteins in solution. The technique is amenable to very large protein complexes and to dynamic particles with different conformational states. It is therefore ideally suited to the analysis of some flagellar motor components. Indeed, we recently used the method to analyze the solution structure of the flagellar motor protein FliG, which when combined with high-resolution snapshots of conformational states from crystal structures, led to insights into conformational transitions that are important in mediating the self-assembly of the bacterial flagellar motor. Here, we describe procedures for X-ray scattering data collection of flagellar motor components, data analysis, and interpretation.

  9. Discovery of a Structurally Unique Small Molecule that Inhibits Protein Synthesis

    PubMed Central

    Thakral, Durga; Tae, Hyun Seop

    2017-01-01

    Identifying and characterizing natural products and synthetic small molecules that inhibit biochemical processes such as ribosomal translation can lead to novel sources of molecular probes and therapeutics. The search for new antibiotics has been invigorated by the increasing burden of drug-resistant bacteria and has identified many clinically essential prokaryote-specific ribosome inhibitors. However, the current cohort of antibiotics is limited with regards to bacterial resistance mechanisms because of structural similarity within classes. From a high-throughput screen for translation inhibitors, we discovered a new compound, T6102, which inhibits bacterial protein synthesis in vitro, inhibits bacterial growth of Bacillus subtilis in vivo, and has a chemical structure that appears to be unique among known classes of translation-inhibiting antibiotics. T6102’s unique structure compared to current clinically-utilized antibiotics makes it an exciting new candidate for the development of next-generation antibiotics. PMID:28356892

  10. Radio Brightness Temperatures and Angular Dimensions of Recently Predicted Vl-Bi Small-Scale Structures

    NASA Astrophysics Data System (ADS)

    Opher, R.

    1990-11-01

    RESUMEN. Muestro que analisis recientes publicados de fuentes de radio galacticas y extragalacticas predicen estructuras en pequera escala en fuentes de radio extendidas, remanentes de supernova, vientos protoestelares, nubes moleculares, distorsiones del fondo de 3 K, enanas blancas magnetizadas, estrellas de tipo tardio y el Sol. Discuto las temperatu- ras de brillo de radio de estas estructuras y sus ditnensiones. Muestro que estas estructuras son detectables con las sensibilidades actuales de VLBI (o en el futuro cercano). ABSTRACT. I show that recently published analysis of galactic and extragalactic radio sources make predictions of small-scale structures in extended radio sources, supernovae remnants, protostellar winds, molecu- lar clouds, distortions of the 3 K background, magnetized white dwarf binaries, late-type stars and the sun. I discuss the radio brightness temperatures of these structures and their dimensions. I show that these structures are detectable with present (or near future) VLBI sensitivities. : RADIO SOURCES-EXTENDED

  11. A structural analysis of small vapor-deposited 'multiply twinned' gold particles

    NASA Technical Reports Server (NTRS)

    Yang, C. Y.; Heinemann, K.; Yacaman, M. J.; Poppa, H.

    1979-01-01

    High resolution selected zone dark field, Bragg reflection imaging and weak beam dark field techniques of transmission electron microscopy were used to determine the structure of small gold particles vapor deposited on NaCl substrates. Attention was focused on the analysis of those particles in the 50-150 A range that have pentagonal or hexagonal bright field profiles. These particles have been previously described as multiply twinned crystallites composed of face-centered cubic tetrahedra. The experimental evidence of the present studies can be interpreted on the assumption that the particle structure is a regular icosahedron or decahedron for the hexagonal or the pentagonal particles respectively. The icosahedron is a multiply twinned rhombohedral crystal and the decahedron is a multiply twinned body-centered orthorhombic crystal, each of which constitutes a slight distortion from the face-centered cubic structure.

  12. Magnetism, structure and chemical order in small CoPd clusters: A first-principles study

    NASA Astrophysics Data System (ADS)

    Mokkath, Junais Habeeb

    2014-01-01

    The structural, electronic and magnetic properties of small ComPdn(N=m+n=8,m=0-N) nanoalloy clusters are studied in the framework of a generalized-gradient approximation to density-functional theory. The optimized cluster structures have a clear tendency to maximize the number of nearest-neighbor CoCo pairs. The magnetic order is found to be ferromagnetic-like (FM) for all the ground-state structures. Antiferromagnetic-like spin arrangements were found in some low-lying isomers. The average magnetic moment per atom μ increases approximately linearly with Co content. A remarkable enhancement of the local Co moments is observed as a result of Pd doping. This is a consequence of the increase in the number of Co d holes, due to CoPd charge transfer, combined with the reduced local coordination. The influence of spin-orbit interactions on the cluster properties is also discussed.

  13. Research output after participants complete a Structured Operational Research and Training (SORT IT) course.

    PubMed

    Guillerm, N; Tayler-Smith, K; Dar Berger, S; Bissell, K; Kumar, A M V; Ramsay, A; Reid, A J; Zachariah, R; Harries, A D

    2015-12-21

    Eighteen months after successfully completing one of six Structured Operational Research and Training Initiative (SORT IT) courses, e-mail questionnaires assessing post-course research output were returned by 63 participants (100% response rate). Thirty-two (51%) participants had completed new research projects, 24 (38%) had published papers, 28 (44%) had presented abstracts at conferences, 15 (24%) had facilitated at further OR courses, and 21 (33%) had reviewed scientific papers. Seven (11%) had secured further research funding and 22 (35%) stated that their institutions were involved in implementation or capacity building in operational research. Significant research output continues beyond course completion, further endorsing the value of the SORT IT model.

  14. Thermal Threshold: Research Study on Small Fiber Dysfunction in Distal Diabetic Polyneuropathy

    PubMed Central

    Jimenez-Cohl, Pedro; Grekin, Carlos; Leyton, Cristian; Vargas, Claudio; Villaseca, Roberto

    2012-01-01

    Objective The most commonly used technique for diagnosis of diabetic neuropathy (DN) is nervous conduction (NC). Our hypothesis is that the use of the thermal threshold (TT) technique to evaluate small fiber damage, which precedes large fiber damage, could enable earlier diagnosis and diminish false negatives. Research Design and Methods The study involved 70 asymptomatic patients with type 2 diabetes mellitus (T2DM) all being treated with oral hypoglycemic medication, and having negative metabolic control levels with glycosylated hemoglobin A1c greater than 7% and less than 8%. Diabetic neuropathy was their only evident complication. All other complications or other causes of neuropathy were discarded. Their time of evolution was 1 to 48 months since date of diagnosis of diabetes. Both thermal threshold and sensory and motor nervous conduction were determined in upper and lower limbs. Results Nervous conduction was found normal in 81% and altered in 19% of patients (large fiber neuropathy). Thermal threshold was normal in 57% and altered in 43% of patients (small fiber neuropathy). In those with normal TTs, no case with an altered NC was found (p < 0.001). Patients with altered TTs could have normal (57%) or altered NC (43%). Thus, NC showed a high frequency of false negatives for DN (57% of 30 cases). The frequency of small fiber neuropathy found with the TT test was higher than that of large fiber neuropathy found with the NC test (p < 0.001) and was found at an earlier age. Conclusions The TT test demonstrated a higher frequency of neuropathy than the NC test in clinically asymptomatic T2DM patients. We suggest that small fiber should be studied before large fiber function to diagnosis distal and symmetrical DN. PMID:22401337

  15. Small Business Demand Response with Communicating Thermostats: SMUD's Summer Solutions Research Pilot

    SciTech Connect

    Herter, Karen; Wayland, Seth; Rasin, Josh

    2009-09-25

    This report documents a field study of 78 small commercial customers in the Sacramento Municipal Utility District service territory who volunteered for an integrated energy-efficiency/demand-response (EE-DR) program in the summer of 2008. The original objective for the pilot was to provide a better understanding of demand response issues in the small commercial sector. Early findings justified a focus on offering small businesses (1) help with the energy efficiency of their buildings in exchange for occasional load shed, and (2) a portfolio of options to meet the needs of a diverse customer sector. To meet these expressed needs, the research pilot provided on-site energy efficiency advice and offered participants several program options, including the choice of either a dynamic rate or monthly payment for air-conditioning setpoint control. An analysis of hourly load data indicates that the offices and retail stores in our sample provided significant demand response, while the restaurants did not. Thermostat data provides further evidence that restaurants attempted to precool and reduce AC service during event hours, but were unable to because their air-conditioning units were undersized. On a 100 F reference day, load impacts of all participants during events averaged 14%, while load impacts of office and retail buildings (excluding restaurants) reached 20%. Overall, pilot participants including restaurants had 2007-2008 summer energy savings of 20% and bill savings of 30%. About 80% of participants said that the program met or surpassed their expectations, and three-quarters said they would probably or definitely participate again without the $120 participation incentive. These results provide evidence that energy efficiency programs, dynamic rates and load control programs can be used concurrently and effectively in the small business sector, and that communicating thermostats are a reliable tool for providing air-conditioning load shed and enhancing the ability

  16. Structural and Kinetic Studies of Novel Cytochrome P450 Small-Alkane Hydroxylases

    SciTech Connect

    Arnold, Frances H.

    2012-02-27

    The goals of this project are to investigate (1) the kinetics and stabilities of engineered cytochrome P450 (P450) small alkane hydroxylases and their evolutionary intermediates, (2) the structural basis for catalytic proficiency on small alkanes of these engineered P450s, and (3) the changes in redox control resulting from protein engineering. To reach these goals, we have established new methods for determining the kinetics and stabilities of multicomponent P450s such as CYP153A6. Using these, we were able to determine that CYP153A6 is proficient for hydroxylation of alkanes as small as ethane, an activity that has never been observed previously in any natural P450. To elucidate the structures of the engineered P450s, we obtained x-ray diffraction data for two variants in the P450PMO (propane monooxygenase) lineage and a preliminary structure for the most evolved variant. This structure shows changes in the substrate binding regions of the enzyme and a reduction in active site volume that are consistent with the observed changes in substrate specificity from fatty acids in the native enzyme to small alkanes in P450PMO. We also constructed semi-rational designed libraries mutating only residues in the enzyme active site that in one round of mutagenesis and screening produced variants that achieved nearly half of the activity of the most evolved enzymes of the P450PMO lineage. Finally, we found that changes in redox properties of the laboratory-evolved P450 alkane hydroxylases did not reflect the improvement in their electron transfer efficiency. The heme redox potential remained constant throughout evolution, while activity increased and coupling efficiency improved from 10% to 90%. The lack of correlation between heme redox potential and enzyme activity and coupling efficiency led us to search for other enzyme properties that could be better predictors for activity towards small alkanes, specifically methane. We investigated the oxidation potential of the radical

  17. Solution structure and excitation energy transfer in phycobiliproteins of Acaryochloris marina investigated by small angle scattering.

    PubMed

    Golub, M; Combet, S; Wieland, D C F; Soloviov, D; Kuklin, A; Lokstein, H; Schmitt, F-J; Olliges, R; Hecht, M; Eckert, H-J; Pieper, J

    2017-04-01

    The structure of phycobiliproteins of the cyanobacterium Acaryochloris marina was investigated in buffer solution at physiological temperatures, i.e. under the same conditions applied in spectroscopic experiments, using small angle neutron scattering. The scattering data of intact phycobiliproteins in buffer solution containing phosphate can be well described using a cylindrical shape with a length of about 225Å and a diameter of approximately 100Å. This finding is qualitatively consistent with earlier electron microscopy studies reporting a rod-like shape of the phycobiliproteins with a length of about 250 (M. Chen et al., FEBS Letters 583, 2009, 2535) or 300Å (J. Marquart et al., FEBS Letters 410, 1997, 428). In contrast, phycobiliproteins dissolved in buffer lacking phosphate revealed a splitting of the rods into cylindrical subunits with a height of 28Å only, but also a pronounced sample aggregation. Complementary small angle neutron and X-ray scattering experiments on phycocyanin suggest that the cylindrical subunits may represent either trimeric phycocyanin or trimeric allophycocyanin. Our findings are in agreement with the assumption that a phycobiliprotein rod with a total height of about 225Å can accommodate seven trimeric phycocyanin subunits and one trimeric allophycocyanin subunit, each of which having a height of about 28Å. The structural information obtained by small angle neutron and X-ray scattering can be used to interpret variations in the low-energy region of the 4.5K absorption spectra of phycobiliproteins dissolved in buffer solutions containing and lacking phosphate, respectively.

  18. Impact of size, secondary structure, and counterions on the binding of small ribonucleic acids to layered double hydroxide nanoparticles.

    PubMed

    Rodriguez, Blanca V; Pescador, Jorge; Pollok, Nicole; Beall, Gary W; Maeder, Corina; Lewis, L Kevin

    2015-12-30

    Use of ribonucleic acid (RNA) interference to regulate protein expression has become an important research topic and gene therapy tool, and therefore, finding suitable vehicles for delivery of small RNAs into cells is of crucial importance. Layered double metal hydroxides such as hydrotalcite (HT) have shown great promise as nonviral vectors for transport of deoxyribose nucleic acid (DNA), proteins, and drugs into cells, but the adsorption of RNAs to these materials has been little explored. In this study, the binding of small RNAs with different lengths and levels of secondary structure to HT nanoparticles has been analyzed and compared to results obtained with small DNAs in concurrent experiments. Initial experiments established the spectrophotometric properties of HT in aqueous solutions and determined that HT particles could be readily sedimented with near 100% efficiencies. Use of RNA+HT cosedimentation experiments as well as electrophoretic mobility shift assays demonstrated strong adsorption of RNA 25mers to HT, with twofold greater binding of single-stranded RNAs relative to double-stranded molecules. Strong affinities were also observed with ssRNA and dsRNA 54mers and with more complex transfer RNA molecules. Competition binding and RNA displacement experiments indicated that RNA-HT associations were strong and were only modestly affected by the presence of high concentrations of inorganic anions.

  19. Modeling and small-angle neutron scattering spectra of chromatin supernucleosomal structures at genome scale

    NASA Astrophysics Data System (ADS)

    Ilatovskiy, Andrey V.; Lebedev, Dmitry V.; Filatov, Michael V.; Grigoriev, Mikhail; Petukhov, Michael G.; Isaev-Ivanov, Vladimir V.

    2011-11-01

    Eukaryotic genome is a highly compacted nucleoprotein complex organized in a hierarchical structure based on nucleosomes. Detailed organization of this structure remains unknown. In the present work we developed algorithms for geometry modeling of the supernucleosomal chromatin structure and for computing distance distribution functions and small-angle neutron scattering (SANS) spectra of the genome-scale (˜106 nucleosomes) chromatin structure at residue resolution. Our physical nucleosome model was based on the mononucleosome crystal structure. A nucleosome was assumed to be rigid within a local coordinate system. Interface parameters between nucleosomes can be set for each nucleosome independently. Pair distance distributions were computed with Monte Carlo simulation. SANS spectra were calculated with Fourier transformation of weighted distance distribution; the concentration of heavy water in solvent and probability of H/D exchange were taken into account. Two main modes of supernucleosomal structure generation were used. In a free generation mode all interface parameters were chosen randomly, whereas nucleosome self-intersections were not allowed. The second generation mode (generation in volume) enabled spherical or cubical wall restrictions. It was shown that calculated SANS spectra for a number of our models were in general agreement with available experimental data.

  20. Small-scale spatial structuring of interstitial invertebrates on three embayed beaches, Sydney, Australia

    NASA Astrophysics Data System (ADS)

    Cooke, Belinda C.; Goodwin, Ian D.; Bishop, Melanie J.

    2014-10-01

    An understanding of ecological processes hinges upon an understanding of the spatial structuring of their key biotic components. Interstitial invertebrates are a ubiquitous and ecologically important component of sandy beach ecosystems. As many sandy beach taxa have limited dispersal, it may be expected that their populations exhibit a high degree of spatial structuring, yet the spatial scales across which they display baseline variability remain largely unknown. To assess (1) whether interstitial invertebrates display patchiness on embayed sandy beaches, (2) whether the size of patches they form is consistent across three geographically proximal beaches, (3) the key environmental correlates of this variation and (4) its taxonomic dependence, samples were collected at regular (0.5 m) intervals along 15 m long geomorphically similar stretches of three proximal intermediate beaches and analyses of spatial autocorrelation were conducted. On each of the three beaches, interstitial invertebrate communities formed patches of 2-4.5 m in diameter. Spatial structuring of invertebrate communities was driven by harpacticoid copepods and gastrotrichs, and corresponded to spatial structuring of sediments. Sediments, however, explained only 33% of spatial variation in faunal communities, indicating the importance of other abiotic and/or biotic factors. Our study highlights that even on seemingly homogeneous sandy beaches, faunal communities may display considerable small-scale spatial structuring. Examination of spatial structure may lead to a greater understanding of the ecological processes in this system.

  1. Development of a structured undergraduate research experience: Framework and implications.

    PubMed

    Brown, Anne M; Lewis, Stephanie N; Bevan, David R

    2016-09-10

    Participating in undergraduate research can be a pivotal experience for students in life science disciplines. Development of critical thinking skills, in addition to conveying scientific ideas in oral and written formats, is essential to ensuring that students develop a greater understanding of basic scientific knowledge and the research process. Modernizing the current life sciences research environment to accommodate the growing demand by students for experiential learning is needed. By developing and implementing a structured, theory-based approach to undergraduate research in the life sciences, specifically biochemistry, it has been successfully shown that more students can be provided with a high-quality, high-impact research experience. The structure of this approach allowed students to develop novel, independent projects in a computational molecular modeling lab. Students engaged in an experience in which career goals, problem-solving skills, time management skills, and independence in a research lab were developed. After experiencing this approach to undergraduate research, students reported feeling challenged to think critically and prepared for future career paths. The approach allowed for a progressive learning environment where more undergraduate students could participate in publishable research. Future areas for development include implementation in a bench-top lab and extension to disciplines beyond biochemistry. In this study, it has been shown that utilizing the structured approach to undergraduate research could allow for more students to experience undergraduate research and develop into more confident, independent life scientists well prepared for graduate schools and professional research environments. © 2016 by The International Union of Biochemistry and Molecular Biology, 44(5):463-474, 2016.

  2. X-Ray Structural Study of Amyloid-Like Fibrils of Tau Peptides Bound to Small-Molecule Ligands.

    PubMed

    Tayeb-Fligelman, Einav; Landau, Meytal

    2017-01-01

    Atomic structures of Tau involved in Alzheimer's disease complexed with small molecule binders are the first step to define the Tau pharmacophore, leading the way to a structure-based design of improved diagnostics and therapeutics. Yet the partially disordered and polymorphic nature of Tau hinders structural analyses. Fortunately, short segments from amyloid proteins, which exhibit similar biophysical properties to the full-length proteins, also form fibrils and oligomers, and their atomic structures can be determined using X-ray microcrystallography. Such structures were successfully used to design amyloid inhibitors. This chapter describes experimental procedures used to determine crystal structures of Tau peptide segments in complex with small-molecule binders.

  3. Selected achievements, science directions, and new opportunities for the WEBB small watershed research program

    USGS Publications Warehouse

    Glynn, Pierre D.; Larsen, Matthew C.; Greene, Earl A.; Buss, Heather L.; Clow, David W.; Hunt, Randall J.; Mast, M. Alisa; Murphy, Sheila F.; Peters, Norman E.; Sebestyen, Stephen D.; Shanley, James B.; Walker, John F.

    2009-01-01

    Over nearly two decades, the Water, Energy, and Biogeochemical Budgets (WEBB) small watershed research program of the U.S. Geological Survey (USGS) has documented how water and solute fluxes, nutrient, carbon, and mercury dynamics, and weathering and sediment transport respond to natural and humancaused drivers, including climate, climate change, and atmospheric deposition. Together with a continued and increasing focus on the effects of climate change, more investigations are needed that examine ecological effects (e.g., evapotranspiration, nutrient uptake) and responses (e.g., species abundances, biodiversity) that are coupled with the physical and chemical processes historically observed in the WEBB program. Greater use of remote sensing, geographic modeling, and habitat/watershed modeling tools is needed, as is closer integration with the USGS-led National Phenology Network. Better understanding of process and system response times is needed. The analysis and observation of land-use and climate change effects over time should be improved by pooling data obtained by the WEBB program during the last two decades with data obtained earlier and (or) concurrently from other research and monitoring studies conducted at or near the five WEBB watershed sites. These data can be supplemented with historical and paleo-environmental information, such as could be obtained from tree rings and lake cores. Because of the relatively pristine nature and small size of its watersheds, the WEBB program could provide process understanding and basic data to better characterize and quantify ecosystem services and to develop and apply indicators of ecosystem health. In collaboration with other Federal and State watershed research programs, the WEBB program has an opportunity to contribute to tracking the short-term dynamics and long-term evolution of ecosystem services and health indicators at a multiplicity of scales across the landscape. 

  4. CONFERENCE REPORT: Summary of the 16th IAEA Technical Meeting on 'Research using Small Fusion Devices'

    NASA Astrophysics Data System (ADS)

    Gribkov, V.; Van Oost, G.; Malaquias, A.; Herrera, J.

    2006-10-01

    Common research topics that are being studied in small, medium and large devices such as H-mode like or improved confinement, turbulence and transport are reported. These included modelling and diagnostic developments for edge and core, to characterize plasma density, temperature, electric potential, plasma flows, turbulence scale, etc. Innovative diagnostic methods were designed and implemented which could be used to develop experiments in small devices (in some cases not possible in large devices due to higher power deposition) to allow a better understanding of plasma edge and core properties. Reports are given addressing research in linear devices that can be used to study particular plasma physics topics relevant for other magnetic confinement devices such as the radial transport and the modelling of self-organized plasma jets involved in spheromak-like plasma formation. Some aspects of the work presented are of interest to the astrophysics community since they are believed to shed light on the basis of the physics of stellar jets. On the dense magnetized plasmas (DMP) topic, the present status of research, operation of new devices, plasma dynamics modelling and diagnostic developments is reported. The main devices presented belong to the class of Z-pinches, mostly plasma foci, and several papers were presented under this topic. The physics of DMP is important both for the main-stream fusion investigations as well as for providing the basis for elaboration of new concepts. New high-current technology introduced in the DMP devices design and construction make these devices nowadays more reliably fitted to various applications and give the possibility to widen the energy range used by them in both directions—to the multi-MJ level facilities and down to miniature plasma focus devices with energy of just a few J.

  5. Structure based approaches for targeting non-coding RNAs with small molecules

    PubMed Central

    Shortridge, Matthew D.; Varani, Gabriele

    2015-01-01

    The increasing appreciation of the central role of non-coding RNAs (miRNAs and long non coding RNAs) in chronic and degenerative human disease makes them attractive therapeutic targets. This would not be unprecedented: the bacterial ribosomal RNA is a mainstay for antibacterial treatment, while the conservation and functional importance of viral RNA regulatory elements has long suggested they would constitute attractive targets for new antivirals. Oligonucleotide-based chemistry has obvious appeals but also considerable pharmacological limitations that are yet to be addressed satisfactorily. Recent studies identifying small molecules targeting non-coding RNAs may provide an alternative approach to oligonucleotide methods. Here we review recent work investigating new structural and chemical principles for targeting RNA with small molecules. PMID:25687935

  6. Biosimilar structural comparability assessment by NMR: from small proteins to monoclonal antibodies

    PubMed Central

    Japelj, Boštjan; Ilc, Gregor; Marušič, Jaka; Senčar, Jure; Kuzman, Drago; Plavec, Janez

    2016-01-01

    Biosimilar drug products must have a demonstrated similarity with respect to the reference product’s molecules in order to ensure both the effectiveness of the drug and the patients’ safety. In this paper the fusion framework of a highly sensitive NMR fingerprinting approach for conformational changes and mathematically-based biosimilarity metrics is introduced. The final goal is to translate the complex spectral information into biosimilarity scores, which are then used to estimate the degree of similarity between the biosimilar and the reference product. The proposed method was successfully applied to a small protein, i.e., filgrastim (neutropenia treatment), which is the first biosimilar approved in the United States, and a relatively large protein, i.e., monoclonal antibody rituximab (lymphoma treatment). This innovative approach introduces a new level of sensitivity to structural changes that are induced by, e.g., a small pH shift or other changes in the protein formulation. PMID:27578487

  7. Biosimilar structural comparability assessment by NMR: from small proteins to monoclonal antibodies

    NASA Astrophysics Data System (ADS)

    Japelj, Boštjan; Ilc, Gregor; Marušič, Jaka; Senčar, Jure; Kuzman, Drago; Plavec, Janez

    2016-08-01

    Biosimilar drug products must have a demonstrated similarity with respect to the reference product’s molecules in order to ensure both the effectiveness of the drug and the patients’ safety. In this paper the fusion framework of a highly sensitive NMR fingerprinting approach for conformational changes and mathematically-based biosimilarity metrics is introduced. The final goal is to translate the complex spectral information into biosimilarity scores, which are then used to estimate the degree of similarity between the biosimilar and the reference product. The proposed method was successfully applied to a small protein, i.e., filgrastim (neutropenia treatment), which is the first biosimilar approved in the United States, and a relatively large protein, i.e., monoclonal antibody rituximab (lymphoma treatment). This innovative approach introduces a new level of sensitivity to structural changes that are induced by, e.g., a small pH shift or other changes in the protein formulation.

  8. Improving small-angle X-ray scattering data for structural analyses of the RNA world

    PubMed Central

    Rambo, Robert P.; Tainer, John A.

    2010-01-01

    Defining the shape, conformation, or assembly state of an RNA in solution often requires multiple investigative tools ranging from nucleotide analog interference mapping to X-ray crystallography. A key addition to this toolbox is small-angle X-ray scattering (SAXS). SAXS provides direct structural information regarding the size, shape, and flexibility of the particle in solution and has proven powerful for analyses of RNA structures with minimal requirements for sample concentration and volumes. In principle, SAXS can provide reliable data on small and large RNA molecules. In practice, SAXS investigations of RNA samples can show inconsistencies that suggest limitations in the SAXS experimental analyses or problems with the samples. Here, we show through investigations on the SAM-I riboswitch, the Group I intron P4-P6 domain, 30S ribosomal subunit from Sulfolobus solfataricus (30S), brome mosaic virus tRNA-like structure (BMV TLS), Thermotoga maritima asd lysine riboswitch, the recombinant tRNAval, and yeast tRNAphe that many problems with SAXS experiments on RNA samples derive from heterogeneity of the folded RNA. Furthermore, we propose and test a general approach to reducing these sample limitations for accurate SAXS analyses of RNA. Together our method and results show that SAXS with synchrotron radiation has great potential to provide accurate RNA shapes, conformations, and assembly states in solution that inform RNA biological functions in fundamental ways. PMID:20106957

  9. Impact of small-scale vegetation structure on tephra layer preservation.

    PubMed

    Cutler, Nick A; Shears, Olivia M; Streeter, Richard T; Dugmore, Andrew J

    2016-11-15

    The factors that influence tephra layer taphonomy are poorly understood, but vegetation cover is likely to play a role in the preservation of terrestrial tephra deposits. The impact of vegetation on tephra layer preservation is important because: 1) the morphology of tephra layers could record key characteristics of past land surfaces and 2) vegetation-driven variability in tephra thickness could affect attempts to infer eruption and dispersion parameters. We investigated small- (metre-) scale interactions between vegetation and a thin (<10 cm), recent tephra layer. We conducted surveys of vegetation structure and tephra thickness at two locations which received a similar tephra deposit, but had contrasting vegetation cover (moss vs shrub). The tephra layer was thicker and less variable under shrub cover. Vegetation structure and layer thickness were correlated on the moss site but not under shrub cover, where the canopy reduced the influence of understory vegetation on layer morphology. Our results show that vegetation structure can influence tephra layer thickness on both small and medium (site) scales. These findings suggest that some tephra layers may carry a signal of past vegetation cover. They also have implications for the sampling effort required to reliably estimate the parameters of initial deposits.

  10. Theoretical study of structure, stability, and the hydrolysis reactions of small iridium oxide nanoclusters.

    PubMed

    Zhou, Xin; Yang, Jingxiu; Li, Can

    2012-10-11

    The geometric structures and relative stabilities of small iridium oxide nanoclusters, Ir(m)O(n) (m = 1-5 and n = 1-2m), have been systematically investigated using density functional theory (DFT) calculations at the B3LYP level. Our results show that the lowest-energy structures of these clusters can be obtained by the sequential oxidation of small "core" iridium clusters. The iridium-monoxide-like clusters have relatively higher stability because of their relatively high binding energy and second difference in energies. On the basis of the optimized lowest-energy structures of neutral and cationic (IrO(2))(n) (n = 1-5), DFT has been used to study the hydrolysis reaction of these clusters with water molecules. The calculated results show that the addition of water molecules to the cationic species is much easier than the neutral ones. The overall hydrolysis reaction energies are more exothermic for the cationic clusters than for the neutral clusters. Our calculations indicate that H(2)O can be more easily split on the cationic iridium oxide clusters than on the neutral clusters.

  11. Impact of small-scale vegetation structure on tephra layer preservation

    PubMed Central

    Cutler, Nick A.; Shears, Olivia M.; Streeter, Richard T.; Dugmore, Andrew J.

    2016-01-01

    The factors that influence tephra layer taphonomy are poorly understood, but vegetation cover is likely to play a role in the preservation of terrestrial tephra deposits. The impact of vegetation on tephra layer preservation is important because: 1) the morphology of tephra layers could record key characteristics of past land surfaces and 2) vegetation-driven variability in tephra thickness could affect attempts to infer eruption and dispersion parameters. We investigated small- (metre-) scale interactions between vegetation and a thin (<10 cm), recent tephra layer. We conducted surveys of vegetation structure and tephra thickness at two locations which received a similar tephra deposit, but had contrasting vegetation cover (moss vs shrub). The tephra layer was thicker and less variable under shrub cover. Vegetation structure and layer thickness were correlated on the moss site but not under shrub cover, where the canopy reduced the influence of understory vegetation on layer morphology. Our results show that vegetation structure can influence tephra layer thickness on both small and medium (site) scales. These findings suggest that some tephra layers may carry a signal of past vegetation cover. They also have implications for the sampling effort required to reliably estimate the parameters of initial deposits. PMID:27845415

  12. SM-TF: A structural database of small molecule-transcription factor complexes.

    PubMed

    Xu, Xianjin; Ma, Zhiwei; Sun, Hongmin; Zou, Xiaoqin

    2016-06-30

    Transcription factors (TFs) are the proteins involved in the transcription process, ensuring the correct expression of specific genes. Numerous diseases arise from the dysfunction of specific TFs. In fact, over 30 TFs have been identified as therapeutic targets of about 9% of the approved drugs. In this study, we created a structural database of small molecule-transcription factor (SM-TF) complexes, available online at http://zoulab.dalton.missouri.edu/SM-TF. The 3D structures of the co-bound small molecule and the corresponding binding sites on TFs are provided in the database, serving as a valuable resource to assist structure-based drug design related to TFs. Currently, the SM-TF database contains 934 entries covering 176 TFs from a variety of species. The database is further classified into several subsets by species and organisms. The entries in the SM-TF database are linked to the UniProt database and other sequence-based TF databases. Furthermore, the druggable TFs from human and the corresponding approved drugs are linked to the DrugBank. © 2016 Wiley Periodicals, Inc.

  13. Cosmic Microwave Background Small-Scale Structure: I. Observations of the Foreground Emission

    NASA Astrophysics Data System (ADS)

    Schmelz, Joan T.; Verschuur, Gerrit L.

    2017-01-01

    The derivation of the small-scale structure in the cosmic microwave background (CMB) relies on an accurate subtraction of foreground signals from the Milky Way Galaxy. Known sources include thermal emission from interstellar cirrus, galactic synchrotron emission resulting from interactions between cosmic ray electrons and magnetic fields, and electron-ion free-free emission from interstellar H II regions. Additional sources include spinning and spinning-wobbling dust grains, and emission from rotational transitions of carbon monoxide. Verschuur (2015 and references therein) showed many examples of connections, associations, and overlaps of galactic HI and CMB structure. Clark et al. (2014) showed that the long, thin filamentary features seen in the high sensitivity, high dynamic range Galactic Arecibo L-Band Feed Array (GALFA) HI survey appear to be aligned along magnetic field directions, which are inferred from the optical polarization of star light. Clark et al. (2015) took this important discovery a step further, relating those magnetic field orientations to the polarized PLANCK 353 GHz dust emission. These results imply that the neutral hydrogen in the interstellar medium is tightly coupled to the galactic magnetic field, which requires a population of electrons. Taken together, these HI results suggest a candidate for a previously unidentified foreground component that may need to be understood in order to improve our ability to measure and interpret the CMB small-scale structure. This work is supported by NASA and NSF.

  14. Mechanistic characterization and crystal structure of a small molecule inactivator bound to plasminogen activator inhibitor-1

    PubMed Central

    Li, Shih-Hon; Reinke, Ashley A.; Sanders, Karen L.; Emal, Cory D.; Whisstock, James C.; Stuckey, Jeanne A.; Lawrence, Daniel A.

    2013-01-01

    Plasminogen activator inhibitor type-1 (PAI-1) is a member of the serine protease inhibitor (serpin) family. Excessive PAI-1 activity is associated with human disease, making it an attractive pharmaceutical target. However, like other serpins, PAI-1 has a labile structure, making it a difficult target for the development of small molecule inhibitors, and to date, there are no US Food and Drug Administration–approved small molecule inactivators of any serpins. Here we describe the mechanistic and structural characterization of a high affinity inactivator of PAI-1. This molecule binds to PAI-1 reversibly and acts through an allosteric mechanism that inhibits PAI-1 binding to proteases and to its cofactor vitronectin. The binding site is identified by X-ray crystallography and mutagenesis as a pocket at the interface of β-sheets B and C and α-helix H. A similar pocket is present on other serpins, suggesting that this site could be a common target in this structurally conserved protein family. PMID:24297881

  15. Impact of small-scale vegetation structure on tephra layer preservation

    NASA Astrophysics Data System (ADS)

    Cutler, Nick A.; Shears, Olivia M.; Streeter, Richard T.; Dugmore, Andrew J.

    2016-11-01

    The factors that influence tephra layer taphonomy are poorly understood, but vegetation cover is likely to play a role in the preservation of terrestrial tephra deposits. The impact of vegetation on tephra layer preservation is important because: 1) the morphology of tephra layers could record key characteristics of past land surfaces and 2) vegetation-driven variability in tephra thickness could affect attempts to infer eruption and dispersion parameters. We investigated small- (metre-) scale interactions between vegetation and a thin (<10 cm), recent tephra layer. We conducted surveys of vegetation structure and tephra thickness at two locations which received a similar tephra deposit, but had contrasting vegetation cover (moss vs shrub). The tephra layer was thicker and less variable under shrub cover. Vegetation structure and layer thickness were correlated on the moss site but not under shrub cover, where the canopy reduced the influence of understory vegetation on layer morphology. Our results show that vegetation structure can influence tephra layer thickness on both small and medium (site) scales. These findings suggest that some tephra layers may carry a signal of past vegetation cover. They also have implications for the sampling effort required to reliably estimate the parameters of initial deposits.

  16. NASTRAN DMAP Fuzzy Structures Analysis: Summary of Research

    NASA Technical Reports Server (NTRS)

    Sparrow, Victor W.

    2001-01-01

    The main proposed tasks of Cooperative Agreement NCC1-382 were: (1) developing MSC/NASTRAN DMAP language scripts to implement the Soize fuzzy structures approach for modeling the dynamics of complex structures; (2) benchmarking the results of the new code to those for a cantilevered beam in the literature; and (3) testing and validating the new code by comparing the fuzzy structures results to NASA Langley experimental and conventional finite element results for two model test structures representative of aircraft fuselage sidewall construction: (A) a small aluminum test panel (SLP, single longeron panel) with a single longitudinal stringer attached with bolts; and (B) a 47 by 72 inch flat aluminum fuselage panel (AFP, aluminum fuselage panel) including six longitudinal stringers and four frame stiffeners attached with rivets.

  17. Research Advances on Structural Characterization of Resistant Starch and Its Structure-Physiological Function Relationship: A Review.

    PubMed

    Ma, Zhen; Boye, Joyce I

    2016-09-19

    Resistant starch (RS) is defined as the fraction of starch that escapes digestion in the small intestine due to either difficult enzyme/starch contact or to the strength of the crystalline regions formed both in native starch and in those retrograded starch. RS occurs naturally in some foods, and some may be generated in others as the results of several processing conditions. A variety of techniques have been employed to obtain structural characteristics of resistant starch such as their crystallinity, structural order, chain length distribution and conformation, helicity, and double helical structures. These structure plays an important role in determining the physiological properties of RS such as their prebiotic and hypoglycaemic properties. However, such topic on structural characterization of RS and their structure-physiological function relationship have not been reviewed in previous literatures. Therefore, this review focuses on the past and current achievements of research on structural characterizations of a range of resistant starch prepared from different sources of native starches as a result of a variety of processing conditions. The potential relationships between the structure and the physiological properties of RS which is of paramount importance for the furtherance understanding and application of RS are also reviewed in this study.

  18. Effective small group teaching strategies for research supervision - A case study

    NASA Astrophysics Data System (ADS)

    Pathirana, Assela

    2010-05-01

    UNESCO-IHE's students are unique in several aspects: they are mid-career professionals separated from their last university experience by a number of years in the profession, they are from diverse social and cultural backgrounds, and they often have relatively clear understanding on the diverse problems in the practice of engineering in their respective countries and are focused on solving those. As a result of the diversity in many forms, managing effective groups during the research phase of the UNESCO-IHE master's course pose considerable challenge. In this paper, we present a unique combination of tools and approaches that are employed in managing a small group of students (between five and ten) in one study area, who were working on diverse research topics that had the common denominator of mathematical modelling. We blend a number of traditional (e.g. seminars, group discussions, focused training sessions) and non-traditional (e.g. Using collaboration platforms like WIKI, peer-learning) approaches so that the cohesion of the group in maintained and every member benefits from being a part of the group. Four years of experience with employing this blend of tools on a six-month long master's research programme showed us: The approach motivates the students to perform focusing not only on the end-goal of their research study, but on the process of day to day work that lead to that goal. The students' self-confidence is often enhanced by being a part of close-knit group. Initial workload of the teacher increases significantly by this approach, but later this is more than compensated by the fact that the teacher has to do little maintain the momentum. Both strong and not so-strong students equally benefit from the approach. A significant number of students develop a keen interest in being involved in research further. (e.g. engaging in doctoral studies.)

  19. 2011 Plant Lipids: Structure, Metabolism, & Function Gordon Research Conference

    SciTech Connect

    Christopher Benning

    2011-02-04

    This is the second Gordon Research Conference on 'Plant Lipids: Structure, Metabolism & Function'. It covers current topics in lipid structure, metabolism and function in eukaryotic photosynthetic organisms including seed plants, algae, mosses and ferns. Work in photosynthetic bacteria is considered as well as it serves the understanding of specific aspects of lipid metabolism in plants. Breakthroughs are discussed in research on plant lipids as diverse as glycerolipids, sphingolipids, lipids of the cell surface, isoprenoids, fatty acids and their derivatives. The program covers nine concepts at the forefront of research under which afore mentioned plant lipid classes are discussed. The goal is to integrate areas such as lipid signaling, basic lipid metabolism, membrane function, lipid analysis, and lipid engineering to achieve a high level of stimulating interaction among diverse researchers with interests in plant lipids. One Emphasis is on the dynamics and regulation of lipid metabolism during plant cell development and in response to environmental factors.

  20. THE OPACITY OF THE INTERGALACTIC MEDIUM DURING REIONIZATION: RESOLVING SMALL-SCALE STRUCTURE

    SciTech Connect

    Emberson, J. D.; Thomas, Rajat M.; Alvarez, Marcelo A.

    2013-02-15

    Early in the reionization process, the intergalactic medium (IGM) would have been quite inhomogeneous on small scales, due to the low Jeans mass in the neutral IGM and the hierarchical growth of structure in a cold dark matter universe. This small-scale structure acted as an important sink during the epoch of reionization, impeding the progress of the ionization fronts that swept out from the first sources of ionizing radiation. Here we present results of high-resolution cosmological hydrodynamics simulations that resolve the cosmological Jeans mass of the neutral IGM in representative volumes several Mpc across. The adiabatic hydrodynamics we follow are appropriate in an unheated IGM, before the gas has had a chance to respond to the photoionization heating. Our focus is determination of the resolution required in cosmological simulations in order to sufficiently sample and resolve small-scale structure regulating the opacity of an unheated IGM. We find that a dark matter particle mass of m {sub dm} {approx}< 50 M {sub Sun} and box size of L {approx}> 1 Mpc are required. With our converged results we show how the mean free path of ionizing radiation and clumping factor of ionized hydrogen depend on the ultraviolet background flux and redshift. We find, for example at z = 10, clumping factors typically of 10-20 for an ionization rate of {Gamma} {approx} (0.3-3) Multiplication-Sign 10{sup -12} s{sup -1}, with corresponding mean free paths of {approx}3-15 Mpc, extending previous work on the evolving mean free path to considerably smaller scales and earlier times.

  1. Wide-range structurally optimized channel for monitoring the certified power of small-core reactors

    NASA Astrophysics Data System (ADS)

    Koshelev, A. S.; Kovshov, K. N.; Ovchinnikov, M. A.; Pikulina, G. N.; Sokolov, A. B.

    2016-12-01

    The results of tests of a prototype version of a channel for monitoring the certified power of small-core reactors performed at the BR-K1 reactor at the All-Russian Scientific Research Institute of Experimental Physics are reported. An SNM-11 counter and commercial KNK-4 and KNK-3 compensated ion chambers were used as neutron detectors in the tested channel, and certified NCMM and CCMM measurement modules controlled by a PC with specialized software were used as measuring instruments. The specifics of metrological assurance of calibration of the channel in the framework of reactor power monitoring are discussed.

  2. Infrared astronomical satellite (IRAS) catalogs and atlases. Volume 7: The small scale structure catalog

    NASA Technical Reports Server (NTRS)

    Helou, George (Editor); Walker, D. W. (Editor)

    1988-01-01

    The Infrared Astronomical Satellite (IRAS) was launched January 26, 1983. During its 300-day mission, it surveyed over 96 pct of the celestial sphere at four infrared wavelengths, centered approximately at 12, 25, 60, and 100 microns. Volume 1 describes the instrument, the mission, and the data reduction process. Volumes 2 through 6 present the observations of the approximately 245,000 individual point sources detected by IRAS; each volume gives sources within a specified range of declination. Volume 7 gives the observations of the approximately 16,000 sources spatially resolved by IRAS and smaller than 8'. This is Volume 7, The Small Scale Structure Catalog.

  3. The correspondence between small-scale coronal structures and the evolving solar magnetic field

    NASA Technical Reports Server (NTRS)

    Webb, D. F.; Moses, J. D.

    1990-01-01

    Solar coronal bright points, first identified in soft X-rays as X-ray Bright Points (XBPs), are compact, short-lived and associated with small bipolar magnetic flux. Coordinated data obtained during recent X-ray sounding rocket flights on August 15 and December 11, 1987 are used to determine the correspondence of XBPs with time-series, ground-based observations of evolving bipolar magnetic structures, He-I dark points, and the network. The results are consistent with the view that coronal bright points are more likely to be associated with the annihilation of preexisting flux than with emerging flux.

  4. Funding and Strategic Alignment Guidance for Infusing Small Business Innovation Research Technology into NASA Programs Associated with the Aeronautics Research Mission Directorate

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.; Steele, Gynelle C.

    2015-01-01

    This report is intended to help NASA program and project managers incorporate Small Business Innovation Research/Small Business Technology Transfer (SBIR/STTR) technologies that have gone through Phase II of the SBIR program into NASA Aeronautics and Mission Directorate (ARMD) programs. Other Government and commercial program managers can also find this information useful.

  5. Small angle X-ray scattering data and structure factor fitting for the study of the quaternary structure of the spermidine N-acetyltransferase SpeG

    PubMed Central

    Weigand, Steven; Filippova, Ekaterina V.; Kiryukhina, Olga; Anderson, Wayne F.

    2015-01-01

    Here we describe the treatment of the small-angle X-ray Scattering (SAXS) data used during SpeG quaternary structure study as part of the research article “Substrate induced allosteric change in the quaternary structure of the spermidine N-acetyltransferase SpeG” published in Journal of Molecular Biology [1]. These data were collected on two separate area detectors as separate dilution series of the SpeG and the SpeG with spermine samples along with data from their companion buffers. The data were radially integrated, corrected for incident beam variation, and scaled to absolute units. After subtraction of volume-fraction scaled buffer scattering and division by the SpeG concentration, multiple scattering curves free of an inter-molecular structure factor were derived from the dilution series. Rather than extrapolating to infinite dilution, the structure factor contribution was estimated by fitting to the full set of data provided by dividing the scattering curves of a dilution series by the curve from the most dilute sample in that series. PMID:26793756

  6. Rainfall simulation experiments with a small portable rainfall simulator: research on runoff generation and soil erosion

    NASA Astrophysics Data System (ADS)

    Iserloh, Thomas; Peter, Klaus Daniel; Fister, Wolfgang; Wirtz, Stefan; Butzen, Verena; Brings, Christine; Marzen, Miriam; Casper, Markus C.; Seeger, Manuel; Ries, Johannes B.

    2015-04-01

    The results of more than 500 rainfall simulations with a small portable rainfall simulator at various locations in West and North Africa and South and Central Europe will be presented. The analysis of this comprehensive database offers results concerning different research objectives: - erodibility of local soils regarding different vegetation cover, stone cover and land uses - runoff generation in gully catchments - process oriented experiments on the influence of sealing and crusting - trail erosion caused by goat- or sheep-trampling - recent erosion on geomorphological forms Runoff coefficients range from 0 to 100 % and eroded material from 0 to 500 g m^-2 during 30 min experiments with a rainfall intensity of 40 mm h^-1.

  7. SMART 1: The first small mission for advanced research in technology

    NASA Astrophysics Data System (ADS)

    Racca, Giuseppe D.

    1999-11-01

    SMART-1 is the first of the Small Missions for Advanced Research in Technology of the ESA Horizons 2000 Science plan. The main mission objective of SMART-1 is to demonstrate innovative and key technologies for scientific deep-space missions. One of the key technologies is the solar electric propulsion used as primary propulsion. The launch is foreseen at the end of 2001 and the total life cost budget allocated to this mission is 50 million ECU (~ 65 million US dollars). Given this budget constraint, the obvious European launch system is as Piggyback passenger of an Ariane 5 in a standard GTO. This imposes stringent spacecraft mass constraints and by consequence limitations on the planetary bodies which can be reached in a given short (1.5-2 years) overall mission lifetime. Alternatively a direct injection into an escape trajectory has been considered with a small launcher, e.g. Eurockot. The planetary bodies identified are the Moon and Earth crossing asteroids or comets, generally classified as Near Earth Objects (NEO). Three mission options are currently envisaged. An Announcement of Opportunity for scientific payload, issued in March 1998, calls for scientific investigations to be performed and indication of the preferred mission options. A second Announcement of Opportunity will be issued in April 1998, concerning the technology payload. SMART-1 will also be a test case for a new approach in the implementation strategy and spacecraft procurement for the ESA Science Programme.

  8. Landscape structure in a managed forest mosaic of the Southern Appalachian Mountains and its influence on songbirds and small mammals

    NASA Astrophysics Data System (ADS)

    Leimgruber, Peter

    Forests in the Appalachian Mountains have been severely affected by logging in the past and little old-growth is left. The remaining forests form a heterogeneous mosaic of different forest successions. A concern for conservation is how additional logging will alter the mosaic and its fauna. I studied the effects of logging on the landscape mosaic and how changes in the landscape structure influence small mammals and birds in the George Washington National Forest, Virginia. My dissertation also included research on how to improve techniques for landscape ecological studies, such as roadside monitoring of birds and mapping of forest resources using remote sensing and Geographic Information Systems (GIS). Because of the scale dependency of landscape-ecological relationships, I investigated how landscape structure in the forest mosaic changes with increasing scales. I determined threshold scales at which structure changed markedly. After establishing a baseline, I examined how logging affected the intensity and location of such thresholds. I found thresholds in landscape structure exist at 400-, 500-, and 800-m intervals from the outer edge of the cut. While logging did not change threshold location and intensity for global landscape indices, such as dominance and contagion, thresholds for focal indices, such as mean patch size and percent cover for early-successional forest, changed markedly. Using GIS, I determined how logging affected small mammals and birds at the landscape scale. I divided the landscape into three zones (zone 1, inside logged areas; zone 2, 20--400 m from logged areas; zone 3, 1000--1500 m from logged areas). Logging changed species presence and richness more drastically in close proximity of cuts than on the landscape and influenced birds more strongly than mammals. In the cuts, edge-adapted birds, such as the indigo bunting (Passerina cyanea), replaced forest interior species, such as the Acadian flycatcher (Empidonax virescens). Most

  9. Structure and orientation of small particles of platinum deposited on NaCl and mica

    NASA Technical Reports Server (NTRS)

    Renou, A.; Gillet, M.

    1979-01-01

    The structure of small platinum particles condensed in vacuum onto NaCl (001), NaCl (111) and mica substrates was studied by electron diffraction and electron microscopy. Results show that above a certain substrate temperature decahedral or icosahedral particles are formed. These particles are practically absent with substrates cleaved in high vacuum. They are always much less numerous than in gold films prepared under the same conditions. Assumptions made to explain this phenomenon are: (1) the initial growth of an abnormal structure of the nuclei as opposed by the substrate; (2) the particles disappear before they attain a size which corresponds to the observations; and (3) the particles result from a coalescence mechanism leading to multiple twinned particles.

  10. Thermally induced structural changes of intrinsically disordered small heat shock protein Hsp22.

    PubMed

    Kazakov, Alexey S; Markov, Denis I; Gusev, Nikolai B; Levitsky, Dmitrii I

    2009-12-01

    We applied different methods (differential scanning calorimetry, circular dichroism, Fourier transform infrared spectroscopy, and intrinsic fluorescence) to investigate the thermal-induced changes in the structure of small heat shock protein Hsp22. It has been shown that this protein undergoes thermal-induced unfolding that occurs within a very broad temperature range (from 27 degrees C to 80 degrees C and above), and this is accompanied by complete disappearance of alpha-helices, significant decrease in beta-sheets content, and by pronounced changes in the intrinsic fluorescence. The results confirm predictions that Hsp22 belongs to the family of intrinsically disordered proteins (IDP) with certain parts of its molecule (presumably, in the alpha-crystallin domain) retaining folded structure and undergoing reversible thermal unfolding. The results are also discussed in terms of downhill folding scenario.

  11. Small-angle neutron scattering and molecular dynamics structural study of gelling DNA nanostars

    NASA Astrophysics Data System (ADS)

    Fernandez-Castanon, J.; Bomboi, F.; Rovigatti, L.; Zanatta, M.; Paciaroni, A.; Comez, L.; Porcar, L.; Jafta, C. J.; Fadda, G. C.; Bellini, T.; Sciortino, F.

    2016-08-01

    DNA oligomers with properly designed sequences self-assemble into well defined constructs. Here, we exploit this methodology to produce bulk quantities of tetravalent DNA nanostars (each one composed of 196 nucleotides) and to explore the structural signatures of their aggregation process. We report small-angle neutron scattering experiments focused on the evaluation of both the form factor and the temperature evolution of the scattered intensity at a nanostar concentration where the system forms a tetravalent equilibrium gel. We also perform molecular dynamics simulations of one isolated tetramer to evaluate the form factor numerically, without resorting to any approximate shape. The numerical form factor is found to be in very good agreement with the experimental one. Simulations predict an essentially temperature-independent form factor, offering the possibility to extract the effective structure factor and its evolution during the equilibrium gelation.

  12. Bidirectional Synaptic Structural Plasticity after Chronic Cocaine Administration Occurs through Rap1 Small GTPase Signaling.

    PubMed

    Cahill, Michael E; Bagot, Rosemary C; Gancarz, Amy M; Walker, Deena M; Sun, HaoSheng; Wang, Zi-Jun; Heller, Elizabeth A; Feng, Jian; Kennedy, Pamela J; Koo, Ja Wook; Cates, Hannah M; Neve, Rachael L; Shen, Li; Dietz, David M; Nestler, Eric J

    2016-02-03

    Dendritic spines are the sites of most excitatory synapses in the CNS, and opposing alterations in the synaptic structure of medium spiny neurons (MSNs) of the nucleus accumbens (NAc), a primary brain reward region, are seen at early versus late time points after cocaine administration. Here we investigate the time-dependent molecular and biochemical processes that regulate this bidirectional synaptic structural plasticity of NAc MSNs and associated changes in cocaine reward in response to chronic cocaine exposure. Our findings reveal key roles for the bidirectional synaptic expression of the Rap1b small GTPase and an associated local synaptic protein translation network in this process. The transcriptional mechanisms and pathway-specific inputs to NAc that regulate Rap1b expression are also characterized. Collectively, these findings provide a precise mechanism by which nuclear to synaptic interactions induce "metaplasticity" in NAc MSNs, and we reveal the specific effects of this plasticity on reward behavior in a brain circuit-specific manner.

  13. Hadronic structure of the photon at small x in holographic QCD

    NASA Astrophysics Data System (ADS)

    Watanabe, Akira; Li, Hsiang-nan

    2016-11-01

    We present our analysis on the photon structure functions at small Bjorken variable x in the framework of the holographic QCD. In the kinematic region, a photon can fluctuate into vector mesons and behaves like a hadron rather than a pointlike particle. Assuming the Pomeron exchange dominance, the dominant hadronic contribution to the structure functions is computed by convoluting the probe and target photon density distributions obtained from the wave functions of the U(1) vector field in the five-dimensional AdS space and the Brower-Polchinski-Strassler-Tan Pomeron exchange kernel. Our calculations are in agreement with both the experimental data from OPAL collaboration at LEP and those calculated from the parton distribution functions of the photon proposed by Glück, Reya, and Schienbein. The predictions presented here will be tested at future linear colliders, such as the planned International Linear Collider.

  14. Small-scale structure and turbulence observed in MAP/WINE)

    NASA Technical Reports Server (NTRS)

    Blix, T. A.

    1989-01-01

    During MAP/WINE small scale structure and turbulence in the mesosphere and lower thermosphere was studied in situ by rocket-borne instruments as well as from the ground by remote sensing techniques. The eight salvoes launched during the campaign resulted in a wealth of information on the dynamical structure of these regions. The experimental results are reviewed and their interpretation is discussed in terms of gravity waves and turbulence. It is shown that eddy diffusion coefficients and turbulent energy dissipation rates may be derived from the in situ measurements in a consistent manner. The observations are also shown to be consistent with the hypothesis that turbulence can be created by a process of gravity wave saturation.

  15. Surface plasmon resonances of arbitrarily shaped nanometallic structures in the small-screening-length limit

    NASA Astrophysics Data System (ADS)

    Schnitzer, Ory; Giannini, Vincenzo; Maier, Stefan A.; Craster, Richard V.

    2016-07-01

    According to the hydrodynamic Drude model, surface plasmon resonances of metallic nanostructures blueshift owing to the non-local response of the metal's electron gas. The screening length characterizing the non-local effect is often small relative to the overall dimensions of the metallic structure, which enables us to derive a coarse-grained non-local description using matched asymptotic expansions; a perturbation theory for the blueshifts of arbitrary-shaped nanometallic structures is then developed. The effect of non-locality is not always a perturbation and we present a detailed analysis of the `bonding' modes of a dimer of nearly touching nanowires where the leading-order eigenfrequencies and eigenmode distributions are shown to be a renormalization of those predicted assuming a local metal permittivity.

  16. Data gaps in evidence-based research on small water enterprises in developing countries.

    PubMed

    Opryszko, Melissa C; Huang, Haiou; Soderlund, Kurt; Schwab, Kellogg J

    2009-12-01

    Small water enterprises (SWEs) are water delivery operations that predominantly provide water at the community level. SWEs operate beyond the reach of piped water systems, selling water to households throughout the world. Their ubiquity in the developing world and access to vulnerable populations suggests that these small-scale water vendors may prove valuable in improving potable water availability. This paper assesses the current literature on SWEs to evaluate previous studies and determine gaps in the evidence base. Piped systems and point-of-use products were not included in this assessment. Results indicate that SWES are active in urban, peri-urban and rural areas of Africa, Asia and Latin America. Benefits of SWEs include: no upfront connection fees; demand-driven and flexible to local conditions; and service to large populations without high costs of utility infrastructure. Disadvantages of SWEs include: higher charges for water per unit of volume compared with infrastructure-based utilities; lack of regulation; operation often outside legal structures; no water quality monitoring; increased potential for conflict with local utilities; and potential for extortion by local officials. No rigorous, evidence-based, peer-reviewed scientific studies that control for confounders examining the effectiveness of SWEs in providing potable water were identified.

  17. Small-Animal Molecular Imaging for Preclinical Cancer Research: .μPET and μ.SPECT.

    PubMed

    Cuccurullo, Vincenzo; Di Stasio, Giuseppe D; Schillirò, Maria L; Mansi, Luigi

    2016-01-01

    Due to different sizes of humans and rodents, the performance of clinical imaging devices is not enough for a scientifically reliable evaluation in mice and rats; therefore dedicated small-animal systems with a much higher sensitivity and spatial resolution, compared to the ones used in humans, are required. Smallanimal imaging represents a cutting-edge research method able to approach an enormous variety of pathologies in which animal models of disease may be used to elucidate the mechanisms underlying the human condition and/or to allow a translational pharmacological (or other) evaluation of therapeutic tools. Molecular imaging, avoiding animal sacrifice, permits repetitive (i.e. longitudinal) studies on the same animal which becomes its own control. In this way also the over time evaluation of disease progression or of the treatment response is enabled. Many different rodent models have been applied to study almost all kind of human pathologies or to experiment a wide series of drugs and/or other therapeutic instruments. In particular, relevant information has been achieved in oncology by in vivo neoplastic phenotypes, obtained through procedures such as subcutaneous tumor grafts, surgical transplantation of solid tumor, orthotopic injection of tumor cells into specific organs/sites of interest, genetic modification of animals to promote tumor-genesis; in this way traditional or innovative treatments, also including gene therapy, of animals with a cancer induced by a known carcinogen may be experimented. Each model has its own disadvantage but, comparing different studies, it is possible to achieve a panoramic and therefore substantially reliable view on the specific subject. Small-animal molecular imaging has become an invaluable component of modern biomedical research that will gain probably an increasingly important role in the next few years.

  18. Image Guided Small Animal Radiation Research Platform: Calibration of Treatment Beam Alignment

    PubMed Central

    Matinfar, Mohammad; Ford, Eric; Iordachita, Iulian; Wong, John; Kazanzides, Peter

    2010-01-01

    Small animal research allows detailed study of biological processes, disease progression, and response to therapy, with the potential to provide a natural bridge to the clinical environment. The Small Animal Radiation Research Platform (SARRP) is a portable system for precision irradiation with beam sizes down to approximately 0.5 mm and optimally planned radiation with on-board cone-beam CT (CBCT) guidance. This paper focuses on the geometric calibration of the system for high-precision irradiation. A novel technique for calibration of the treatment beam is presented, which employs an x-ray camera whose precise positioning need not be known. Using the camera system we acquired a digitally reconstructed 3D “star shot” for gantry calibration, and then developed a technique to align each beam to a common isocenter with the robotic animal positioning stages. The calibration incorporates localization by cone-beam CT guidance. Uncorrected offsets of the beams with respect to the calibration origin ranged from 0.4 mm to 5.2 mm. With corrections, these alignments can be brought to within < 1 mm. The calibration technique was used to deliver a stereotactic-like arc treatment to a phantom constructed with EBT Gafchromic films. All beams were shown to intersect at a common isocenter with a measured beam (FWHM) of approximately 1.07 mm using the 0.5 mm collimated beam. The desired positioning accuracy of the SARRP is 0.25 mm and the results indicate an accuracy of 0.2 mm. To fully realize the radiation localization capabilities of the SARRP, precise geometric calibration is required, as with any such system. The x-ray camera-based technique presented here provides a straightforward and semi-automatic method for system calibration. PMID:19141881

  19. Image-guided small animal radiation research platform: calibration of treatment beam alignment

    NASA Astrophysics Data System (ADS)

    Matinfar, Mohammad; Ford, Eric; Iordachita, Iulian; Wong, John; Kazanzides, Peter

    2009-02-01

    Small animal research allows detailed study of biological processes, disease progression and response to therapy with the potential to provide a natural bridge to the clinical environment. The small animal radiation research platform (SARRP) is a portable system for precision irradiation with beam sizes down to approximately 0.5 mm and optimally planned radiation with on-board cone-beam CT (CBCT) guidance. This paper focuses on the geometric calibration of the system for high-precision irradiation. A novel technique for the calibration of the treatment beam is presented, which employs an x-ray camera whose precise positioning need not be known. Using the camera system we acquired a digitally reconstructed 3D 'star shot' for gantry calibration and then developed a technique to align each beam to a common isocenter with the robotic animal positioning stages. The calibration incorporates localization by cone-beam CT guidance. Uncorrected offsets of the beams with respect to the calibration origin ranged from 0.4 mm to 5.2 mm. With corrections, these alignment errors can be reduced to the sub-millimeter range. The calibration technique was used to deliver a stereotactic-like arc treatment to a phantom constructed with EBT Gafchromic films. All beams were shown to intersect at a common isocenter with a measured beam (FWHM) of approximately 1.07 mm using the 0.5 mm collimated beam. The desired positioning accuracy of the SARRP is 0.25 mm and the results indicate an accuracy of 0.2 mm. To fully realize the radiation localization capabilities of the SARRP, precise geometric calibration is required, as with any such system. The x-ray camera-based technique presented here provides a straightforward and semi-automatic method for system calibration.

  20. The Small Aircraft Transportation System (SATS), Higher Volume Operations (HVO) Concept and Research

    NASA Technical Reports Server (NTRS)

    Baxley, B.; Williams, D.; Consiglio, M.; Adams, C.; Abbott, T.

    2005-01-01

    The ability to conduct concurrent, multiple aircraft operations in poor weather at virtually any airport offers an important opportunity for a significant increase in the rate of flight operations, a major improvement in passenger convenience, and the potential to foster growth of operations at small airports. The Small Aircraft Transportation System, (SATS) Higher Volume Operations (HVO) concept is designed to increase capacity at the 3400 non-radar, non-towered airports in the United States where operations are currently restricted to one-in/one-out procedural separation during low visibility or ceilings. The concept s key feature is that pilots maintain their own separation from other aircraft using air-to-air datalink and on-board software within the Self-Controlled Area (SCA), an area of flight operations established during poor visibility and low ceilings around an airport without Air Traffic Control (ATC) services. While pilots self-separate within the SCA, an Airport Management Module (AMM) located at the airport assigns arriving pilots their sequence based on aircraft performance, position, winds, missed approach requirements, and ATC intent. The HVO design uses distributed decision-making, safe procedures, attempts to minimize pilot and controller workload, and integrates with today's ATC environment. The HVO procedures have pilots make their own flight path decisions when flying in Instrument Metrological Conditions (IMC) while meeting these requirements. This paper summarizes the HVO concept and procedures, presents a summary of the research conducted and results, and outlines areas where future HVO research is required. More information about SATS HVO can be found at http://ntrs.nasa.gov.

  1. Metal ion binding and function in natural and artificial small RNA enzymes from a structural perspective.

    PubMed

    Wedekind, Joseph E

    2011-01-01

    Ribozymes are often perceived as part of an antiquated catalytic arsenal hearkening back to a pre-biotic RNA World that was eventually supplanted by proteins. However, recent genome-wide searches have revealed a plethora of new catalytic RNA motifs that appear to be variations on well-known themes. This suggests that ribozymes have continued to evolve in order to fulfill specific, RNA-essential biological niches. Although such ribozymes are small and catalyze one-step phosphodiester-bond scission reactions, ongoing structure and function analyses at the lab bench have demonstrated that RNA has the capacity for a diverse number of reactions such as carbon-carbon bond formation, and tRNA aminoacylation. Here we describe the fundamental structure and metal binding properties of four naturally occurring RNA enzymes: the hammerhead, hairpin, hepatitis delta virus, and glmS metabolite sensing ribozyme. In addition, we discuss the fold and ion coordination of three artificial ribozymes developed to probe the boundaries of RNA catalysis; these include the leadzyme, the flexizyme, and the Diels-Alder ribozyme. Our approach is to relate structure to function with the knowledge of ideal metal-ion coordination geometry that we have derived herein from surveys of high-resolution small molecule structures. An emergent theme is that natural and artificial ribozymes that catalyze single-step reactions often possess a pre-formed active site. Multivalent ions facilitate RNA active site formation, but can also provide Lewis acid functionality that is necessary for catalysis. When metal ion binding isn't possible, ribozymes make due by ionizing their bases, or by recruiting cofactors that augment their chemical functionality.

  2. Utilization of the Building-Block Approach in Structural Mechanics Research

    NASA Technical Reports Server (NTRS)

    Rouse, Marshall; Jegley, Dawn C.; McGowan, David M.; Bush, Harold G.; Waters, W. Allen

    2005-01-01

    In the last 20 years NASA has worked in collaboration with industry to develop enabling technologies needed to make aircraft safer and more affordable, extend their lifetime, improve their reliability, better understand their behavior, and reduce their weight. To support these efforts, research programs starting with ideas and culminating in full-scale structural testing were conducted at the NASA Langley Research Center. Each program contained development efforts that (a) started with selecting the material system and manufacturing approach; (b) moved on to experimentation and analysis of small samples to characterize the system and quantify behavior in the presence of defects like damage and imperfections; (c) progressed on to examining larger structures to examine buckling behavior, combined loadings, and built-up structures; and (d) finally moved to complicated subcomponents and full-scale components. Each step along the way was supported by detailed analysis, including tool development, to prove that the behavior of these structures was well-understood and predictable. This approach for developing technology became known as the "building-block" approach. In the Advanced Composites Technology Program and the High Speed Research Program the building-block approach was used to develop a true understanding of the response of the structures involved through experimentation and analysis. The philosophy that if the structural response couldn't be accurately predicted, it wasn't really understood, was critical to the progression of these programs. To this end, analytical techniques including closed-form and finite elements were employed and experimentation used to verify assumptions at each step along the way. This paper presents a discussion of the utilization of the building-block approach described previously in structural mechanics research and development programs at NASA Langley Research Center. Specific examples that illustrate the use of this approach are

  3. Challenges During Microstructural Analysis and Mechanical Testing of Small-Scale Pseudoelastic NiTi Structures

    NASA Astrophysics Data System (ADS)

    Hahn, S.; Wagner, M. F.-X.

    2016-06-01

    Most investigations on NiTi-based shape memory alloys involve large-scale bulk material; knowledge about the martensitic transformation in small-scale NiTi structures is still limited. In this paper, we study the microstructures of thin NiTi layers and their mechanical properties, and we discuss typical challenges that arise when experiments are performed on small samples. A physical vapor deposition (PVD) process was used to deposit thin NiTi wires with a cross section of 15 × 15 μm2 and dogbone-shaped samples 5 × 500 μm2. Microstructural properties were characterized by X-ray diffraction, electron backscatter diffraction, and scanning electron microscopy. Moreover, tensile tests were performed using optical strain measurements in order to observe martensite band formation during cyclic loading. The surfaces of the crystalline wires reflect the columnar growth of NiTi during deposition. The wires exhibit pseudoelastic material behavior during tensile testing. Fracture typically occurs along the columns because the column growth direction is perpendicular to the straining direction. Electropolishing removes these local stress raisers and hence increases fracture strains. Our results demonstrate that the pseudoelastic properties of the PVD-processed materials agree well with those of conventional NiTi, and that they provide new opportunities to study the fundamentals of martensitic transformation in small-scale model systems.

  4. The dominating impact of small-scale streambed structural heterogeneity on hyporheic exchange and biogeochemical hotspots in lowland rivers

    NASA Astrophysics Data System (ADS)

    Krause, S.; Gomez, J. D.; Blume, T.; Weatherill, J.; Angermann, L.; Munz, M.; Tecklenburg, C.; Cassidy, N. J.; Wilson, J. L.

    2013-12-01

    Exchange fluxes and residence times of groundwater and surface water at aquifer-river interfaces are driven by hydrodynamic and hydrostatic forcing. While previous research, with a predominantly surface water perspective, has mainly focussed on the impact of bedform controlled advective pumping on hyporheic zone extent and residence times, little attention has been paid to the impact of streambed structural controls on groundwater up-welling patterns and its implications for hyporheic exchange. Following a combined experimental and model-based approach, this paper highlights the impact of small-scale streambed structural variability on spatial patterns of hyporheic exchange flow, residence time distribution and the development of hotspots of biogeochemical cycling in the hyporheic zone of a lowland river. Combining Fibre-optic DTS and active Heat Pulse Sensing, this study identified distinct low conductivities peat and clay structures in the streambed to determine patterns, quantity and temporal dynamics of groundwater up-welling. Model simulations confirmed that streambed structure controlled patterns of groundwater up-welling exceeded the impact of bedform driven fluxes on aquifer-river exchange flow patterns. In addition, enhanced residence times of up-welling groundwater in and around these organic rich structures lead to an increase in dissolved oxygen consumption and the development of anaerobic denitrification hotspots. The resulting increases in streambed nitrate attenuation as well as enhanced production of CO2, CH4 and N2O as respiration end products highlight the importance of biogeochemical hotspots at aquifer-river interfaces under the dominant impact of streambed structural heterogeneity. Conceptual model of streambed hydrofacies controlling groundwater up-welling in a typical lowland river including their effect on heat transport at the aquifer-river interface (the star indicates the temperature of the surface water). B: core logs of exemplary

  5. Activities of the Structures Division, Lewis Research Center

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The purpose of the NASA Lewis Research Center, Structures Division's 1990 Annual Report is to give a brief, but comprehensive, review of the technical accomplishments of the Division during the past calendar year. The report is organized topically to match the Center's Strategic Plan. Over the years, the Structures Division has developed the technology base necessary for improving the future of aeronautical and space propulsion systems. In the future, propulsion systems will need to be lighter, to operate at higher temperatures and to be more reliable in order to achieve higher performance. Achieving these goals is complex and challenging. Our approach has been to work cooperatively with both industry and universities to develop the technology necessary for state-of-the-art advancement in aeronautical and space propulsion systems. The Structures Division consists of four branches: Structural Mechanics, Fatigue and Fracture, Structural Dynamics, and Structural Integrity. This publication describes the work of the four branches by three topic areas of Research: (1) Basic Discipline; (2) Aeropropulsion; and (3) Space Propulsion. Each topic area is further divided into the following: (1) Materials; (2) Structural Mechanics; (3) Life Prediction; (4) Instruments, Controls, and Testing Techniques; and (5) Mechanisms. The publication covers 78 separate topics with a bibliography containing 159 citations. We hope you will find the publication interesting as well as useful.

  6. Structure of the Myotonic Dystrophy Type 2 RNA and Designed Small Molecules That Reduce Toxicity

    PubMed Central

    Park, HaJeung; Lohman, Jeremy R.; Guan, Lirui; Tran, Tuan; Sarkar, Partha; Schatz, George C.; Disney, Matthew D.

    2014-01-01

    Myotonic dystrophy type 2 (DM2) is an untreatable neuromuscular disorder caused by a r(CCUG) expansion (r(CCUG)exp) that folds into an extended hairpin with periodically repeating 2×2 nucleotide internal loops (5’CCUG/3’GUCC). We designed multivalent compounds that improve DM2-associated defects using information about RNA-small molecule interactions. We also report the first crystal structure of r(CCUG)exp refined to 2.35 Å. Structural analysis of the three 5’CCUG/3’GUCC repeat internal loops (L) reveals that the CU pairs in L1 are each stabilized by one hydrogen bond and a water-mediated hydrogen bond while CU pairs in L2 and L3 are stabilized by two hydrogen bonds. Molecular dynamics (MD) simulations reveal that the CU pairs are dynamic and stabilized by Na+ and water molecules. MD simulations of the binding of the small molecule to r(CCUG) repeats reveal that the lowest free energy binding mode occurs via the major groove, in which one C residue is unstacked and the cross-strand nucleotides are displaced. Moreover, we modeled the binding of our dimeric compound to two 5’CCUG/3’GUCC motifs, which shows that the scaffold on which the RNA-binding modules are displayed provides an optimal distance to span two adjacent loops. PMID:24341895

  7. Structure and expression of a novel compact myelin protein – Small VCP-interacting protein (SVIP)

    SciTech Connect

    Wu, Jiawen; Peng, Dungeng; Voehler, Markus; Sanders, Charles R.; Li, Jun

    2013-10-11

    Highlights: •SVIP (small p97/VCP-interacting protein) co-localizes with myelin basic protein (MBP) in compact myelin. •We determined that SVIP is an intrinsically disordered protein (IDP). •The helical content of SVIP increases dramatically during its interaction with negatively charged lipid membrane. •This study provides structural insight into interactions between SVIP and myelin membranes. -- Abstract: SVIP (small p97/VCP-interacting protein) was initially identified as one of many cofactors regulating the valosin containing protein (VCP), an AAA+ ATPase involved in endoplasmic-reticulum-associated protein degradation (ERAD). Our previous study showed that SVIP is expressed exclusively in the nervous system. In the present study, SVIP and VCP were seen to be co-localized in neuronal cell bodies. Interestingly, we also observed that SVIP co-localizes with myelin basic protein (MBP) in compact myelin, where VCP was absent. Furthermore, using nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopic measurements, we determined that SVIP is an intrinsically disordered protein (IDP). However, upon binding to the surface of membranes containing a net negative charge, the helical content of SVIP increases dramatically. These findings provide structural insight into interactions between SVIP and myelin membranes.

  8. Insight into asphaltene nanoaggregate structure inferred by small angle neutron and X-ray scattering.

    PubMed

    Eyssautier, Joëlle; Levitz, Pierre; Espinat, Didier; Jestin, Jacques; Gummel, Jérémie; Grillo, Isabelle; Barré, Loïc

    2011-06-02

    Complementary neutron and X-ray small angle scattering results give prominent information on the asphaltene nanostructure. Precise SANS and SAXS measurements on a large q-scale were performed on the same dilute asphaltene-toluene solution, and absolute intensity scaling was carried out. Direct comparison of neutron and X-ray spectra enables description of a fractal organization made from the aggregation of small entities of 16 kDa, exhibiting an internal fine structure. Neutron contrast variation experiments enhance the description of this nanoaggregate in terms of core-shell disk organization, giving insight into core and shell dimensions and chemical compositions. The nanoaggregates are best described by a disk of total radius 32 Å with 30% polydispersity and a height of 6.7 Å. Composition and density calculations show that the core is a dense and aromatic structure, contrary to the shell, which is highly aliphatic. These results show a good agreement with the general view of the Yen model (Yen, T. F.; et al. Anal. Chem.1961, 33, 1587-1594) and as for the modified Yen model (Mullins, O. C. Energy Fuels2010, 24, 2179-2207), provide characteristic dimensions of the asphaltene nanoaggregate in good solvent.

  9. Self-interacting inelastic dark matter: a viable solution to the small scale structure problems

    NASA Astrophysics Data System (ADS)

    Blennow, Mattias; Clementz, Stefan; Herrero-Garcia, Juan

    2017-03-01

    Self-interacting dark matter has been proposed as a solution to the small-scale structure problems, such as the observed flat cores in dwarf and low surface brightness galaxies. If scattering takes place through light mediators, the scattering cross section relevant to solve these problems may fall into the non-perturbative regime leading to a non-trivial velocity dependence, which allows compatibility with limits stemming from cluster-size objects. However, these models are strongly constrained by different observations, in particular from the requirements that the decay of the light mediator is sufficiently rapid (before Big Bang Nucleosynthesis) and from direct detection. A natural solution to reconcile both requirements are inelastic endothermic interactions, such that scatterings in direct detection experiments are suppressed or even kinematically forbidden if the mass splitting between the two-states is sufficiently large. Using an exact solution when numerically solving the Schrödinger equation, we study such scenarios and find regions in the parameter space of dark matter and mediator masses, and the mass splitting of the states, where the small scale structure problems can be solved, the dark matter has the correct relic abundance and direct detection limits can be evaded.

  10. Cosmic Microwave Background Small-Scale Structure: II. Model of the Foreground Emission

    NASA Astrophysics Data System (ADS)

    Verschuur, Gerrit L.; Schmelz, Joan T.

    2017-01-01

    We have investigated the possibility that a population of galactic electrons may contribute to the small-scale structure in the cosmic microwave background (CMB) found by WMAP and PLANCK. Model calculations of free-free emission from these electrons which include beam dilution produce a nearly flat spectrum. Data at nine frequencies from 22 to 100 GHz were fit with the model, which resulted in excellent values of reduced chi squared. The model involves three unknowns: electron excitation temperature, angular extent of the sources of emission, and emission measure. The resulting temperatures agree with the observed temperatures of related HI features. The derived angular extent of the continuum sources corresponds well with the observed angular extent of HI filamentary structures in the areas under consideration. The derived emission measures can be used to determine the fractional ionization along the path lengths through the emitting volumes of space. Understanding the role that free-free emission plays in the small-scale features observed by PLANCK and WMAP should allow us to create better masks of the galactic foreground. Pursuing such discoveries may yet transform our understanding of the origins of the universe.

  11. Core structure of the U6 small nuclear ribonucleoprotein at 1.7-Å resolution.

    PubMed

    Montemayor, Eric J; Curran, Elizabeth C; Liao, Hong Hong; Andrews, Kristie L; Treba, Christine N; Butcher, Samuel E; Brow, David A

    2014-06-01

    The spliceosome is a dynamic assembly of five small nuclear ribonucleoproteins (snRNPs) that removes introns from eukaryotic pre-mRNA. U6, the most conserved of the spliceosomal small nuclear RNAs (snRNAs), participates directly in catalysis. Here, we report the crystal structure of the Saccharomyces cerevisiae U6 snRNP core containing most of the U6 snRNA and all four RRM domains of the Prp24 protein. It reveals a unique interlocked RNP architecture that sequesters the 5' splice site-binding bases of U6 snRNA. RRMs 1, 2 and 4 of Prp24 form an electropositive groove that binds double-stranded RNA and may nucleate annealing of U4 and U6 snRNAs. Substitutions in Prp24 that suppress a mutation in U6 localize to direct RNA-protein contacts. Our results provide the most comprehensive view to date of a multi-RRM protein bound to RNA and reveal striking coevolution of protein and RNA structure.

  12. Structure of the myotonic dystrophy type 2 RNA and designed small molecules that reduce toxicity.

    PubMed

    Childs-Disney, Jessica L; Yildirim, Ilyas; Park, HaJeung; Lohman, Jeremy R; Guan, Lirui; Tran, Tuan; Sarkar, Partha; Schatz, George C; Disney, Matthew D

    2014-02-21

    Myotonic dystrophy type 2 (DM2) is an incurable neuromuscular disorder caused by a r(CCUG) expansion (r(CCUG)(exp)) that folds into an extended hairpin with periodically repeating 2×2 nucleotide internal loops (5'CCUG/3'GUCC). We designed multivalent compounds that improve DM2-associated defects using information about RNA-small molecule interactions. We also report the first crystal structure of r(CCUG) repeats refined to 2.35 Å. Structural analysis of the three 5'CCUG/3'GUCC repeat internal loops (L) reveals that the CU pairs in L1 are each stabilized by one hydrogen bond and a water-mediated hydrogen bond, while CU pairs in L2 and L3 are stabilized by two hydrogen bonds. Molecular dynamics (MD) simulations reveal that the CU pairs are dynamic and stabilized by Na(+) and water molecules. MD simulations of the binding of the small molecule to r(CCUG) repeats reveal that the lowest free energy binding mode occurs via the major groove, in which one C residue is unstacked and the cross-strand nucleotides are displaced. Moreover, we modeled the binding of our dimeric compound to two 5'CCUG/3'GUCC motifs, which shows that the scaffold on which the RNA-binding modules are displayed provides an optimal distance to span two adjacent loops.

  13. Small-scale Structuring of Ellerman Bombs at the Solar Limb

    NASA Astrophysics Data System (ADS)

    Nelson, C. J.; Scullion, E. M.; Doyle, J. G.; Freij, N.; Erdélyi, R.

    2015-01-01

    Ellerman bombs (EBs) have been widely studied in recent years due to their dynamic, explosive nature and apparent links to the underlying photospheric magnetic field implying that they may be formed by magnetic reconnection in the photosphere. Despite a plethora of researches discussing the morphologies of EBs, there has been a limited investigation of how these events appear at the limb, specifically, whether they manifest as vertical extensions away from the disk. In this article, we make use of high-resolution, high-cadence observations of an Active Region at the solar limb, collected by the CRisp Imaging SpectroPolarimeter (CRISP) instrument, to identify EBs and infer their physical properties. The upper atmosphere is also probed using the Solar Dynamic Observatory's Atmospheric Imaging Assembly (SDO/AIA). We analyze 22 EB events evident within these data, finding that 20 appear to follow a parabolic path away from the solar surface at an average speed of 9 km s-1, extending away from their source by 580 km, before retreating back at a similar speed. These results show strong evidence of vertical motions associated with EBs, possibly explaining the dynamical "flaring" (changing in area and intensity) observed in on-disk events. Two in-depth case studies are also presented that highlight the unique dynamical nature of EBs within the lower solar atmosphere. The viewing angle of these observations allows for a direct linkage between these EBs and other small-scale events in the Hα line wings, including a potential flux emergence scenario. The findings presented here suggest that EBs could have a wider-reaching influence on the solar atmosphere than previously thought, as we reveal a direct linkage between EBs and an emerging small-scale loop, and other near-by small-scale explosive events. However, as previous research found, these extensions do not appear to impact upon the Hα line core, and are not observed by the SDO/AIA EUV filters.

  14. SMALL-SCALE STRUCTURING OF ELLERMAN BOMBS AT THE SOLAR LIMB

    SciTech Connect

    Nelson, C. J.; Doyle, J. G.; Scullion, E. M.; Freij, N.; Erdélyi, R.

    2015-01-01

    Ellerman bombs (EBs) have been widely studied in recent years due to their dynamic, explosive nature and apparent links to the underlying photospheric magnetic field implying that they may be formed by magnetic reconnection in the photosphere. Despite a plethora of researches discussing the morphologies of EBs, there has been a limited investigation of how these events appear at the limb, specifically, whether they manifest as vertical extensions away from the disk. In this article, we make use of high-resolution, high-cadence observations of an Active Region at the solar limb, collected by the CRisp Imaging SpectroPolarimeter (CRISP) instrument, to identify EBs and infer their physical properties. The upper atmosphere is also probed using the Solar Dynamic Observatory's Atmospheric Imaging Assembly (SDO/AIA). We analyze 22 EB events evident within these data, finding that 20 appear to follow a parabolic path away from the solar surface at an average speed of 9 km s{sup –1}, extending away from their source by 580 km, before retreating back at a similar speed. These results show strong evidence of vertical motions associated with EBs, possibly explaining the dynamical ''flaring'' (changing in area and intensity) observed in on-disk events. Two in-depth case studies are also presented that highlight the unique dynamical nature of EBs within the lower solar atmosphere. The viewing angle of these observations allows for a direct linkage between these EBs and other small-scale events in the Hα line wings, including a potential flux emergence scenario. The findings presented here suggest that EBs could have a wider-reaching influence on the solar atmosphere than previously thought, as we reveal a direct linkage between EBs and an emerging small-scale loop, and other near-by small-scale explosive events. However, as previous research found, these extensions do not appear to impact upon the Hα line core, and are not observed by the SDO/AIA EUV filters.

  15. The Use of Structural Equation Modeling in Counseling Psychology Research

    ERIC Educational Resources Information Center

    Martens, Matthew P.

    2005-01-01

    Structural equation modeling (SEM) has become increasingly popular for analyzing data in the social sciences, although several broad reviews of psychology journals suggest that many SEM researchers engage in questionable practices when using the technique. The purpose of this study is to review and critique the use of SEM in counseling psychology…

  16. Chemical Structure and Accidental Explosion Risk in the Research Laboratory

    ERIC Educational Resources Information Center

    Churchill, David G.

    2006-01-01

    Tips that laboratory researchers and beginning graduate students can use to safeguard against explosion hazard with emphasis on clear illustrations of molecular structure are discussed. Those working with hazardous materials must proceed cautiously and may want to consider alternative and synthetic routes.

  17. Research and Development of Rapid Design Systems for Aerospace Structure

    NASA Technical Reports Server (NTRS)

    Schaeffer, Harry G.

    1999-01-01

    This report describes the results of research activities associated with the development of rapid design systems for aerospace structures in support of the Intelligent Synthesis Environment (ISE). The specific subsystems investigated were the interface between model assembly and analysis; and, the high performance NASA GPS equation solver software system in the Windows NT environment on low cost high-performance PCs.

  18. Materials research at Stanford University. [composite materials, crystal structure, acoustics

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Research activity related to the science of materials is described. The following areas are included: elastic and thermal properties of composite materials, acoustic waves and devices, amorphous materials, crystal structure, synthesis of metal-metal bonds, interactions of solids with solutions, electrochemistry, fatigue damage, superconductivity and molecular physics and phase transition kinetics.

  19. Advanced Composite Structures At NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Eldred, Lloyd B.

    2015-01-01

    Dr. Eldred's presentation will discuss several NASA efforts to improve and expand the use of composite structures within aerospace vehicles. Topics will include an overview of NASA's Advanced Composites Project (ACP), Space Launch System (SLS) applications, and Langley's ISAAC robotic composites research tool.

  20. Parameterization of structures in HE composites using surrogate materials: A small angle neutron scattering investigation

    SciTech Connect

    Mang, J.T.; Hjelm, R.P.; Skidmore, C.B.; Howe, P.M.

    1996-07-01

    High explosive materials used in the nuclear stockpile are composites of crystalline high explosives (HE) with binder materials, such as Estane. In such materials, there are naturally occurring density fluctuations (defects) due to cracks, internal (in the HE) and external (in the binder) voids and other artifacts of preparation. Changes in such defects due to material aging can affect the response of explosives due to shock, impact and thermal loading. Modeling efforts are attempting to provide quantitative descriptions of explosive response from the lowest ignition thresholds to the development of full blown detonations and explosions, however, adequate descriptions of these processes require accurate measurements of a number of structural parameters of the HE composite. Since different defects are believed to affect explosive sensitivity in different ways it is necessary to quantitatively differentiate between defect types. The authors report here preliminary results of SANS measurements on surrogates for HE materials. The objective of these measurements was to develop methodologies using SANS techniques to parameterize internal void size distributions in a surrogate material, sugar, to simulate an HE used in the stockpile, HMX. Sugar is a natural choice as a surrogate material, as it has the same crystal structure, has similar intragranular voids and has similar mechanical properties as HMX. It is used extensively as a mock material for explosives. Samples were used with two void size distributions: one with a sufficiently small mean particle size that only small occluded voids are present in significant concentrations, and one where the void sizes could be larger. By using methods in small-angle neutron scattering, they were able to isolate the scattering arising from particle-liquid interfaces and internal voids.

  1. Effects of melatonin and Pycnogenol on small artery structure and function in spontaneously hypertensive rats.

    PubMed

    Rezzani, Rita; Porteri, Enzo; De Ciuceis, Carolina; Bonomini, Francesca; Rodella, Luigi F; Paiardi, Silvia; Boari, Gianluca E M; Platto, Caterina; Pilu, Annamaria; Avanzi, Daniele; Rizzoni, Damiano; Agabiti Rosei, Enrico

    2010-06-01

    It was suggested that oxidative stress has a key role in the development of endothelial dysfunction, as well as microvascular structural alterations. Therefore, we have investigated 2 substances with antioxidant properties: melatonin and Pycnogenol. We treated 7 spontaneously hypertensive rats (SHRs) with melatonin and 7 with Pycnogenol for 6 weeks. We compared results obtained with those observed in 7 SHRs and 7 Wistar-Kyoto normotensive control rats kept untreated. Mesenteric small resistance arteries were dissected and mounted on a wire myograph, and a concentration-response curve to acetylcholine was performed. Aortic contents of metalloproteinase 2, Bax, inducible NO synthase, and cyclooxygenase 2 were evaluated, together with the aortic content of total collagen and collagen subtypes and apoptosis rate. A small reduction in systolic blood pressure was observed. A significant improvement in mesenteric small resistance artery structure and endothelial function was observed in rats treated with Pycnogenol and melatonin. Total aortic collagen content was significantly greater in untreated SHRs compared with Wistar-Kyoto control rats, whereas a full normalization was observed in treated rats. Apoptosis rate was increased in the aortas of untreated SHRs compared with Wistar-Kyoto control rats; an even more pronounced increase was observed in treated rats. Bax and metalloproteinase 2 expressions changed accordingly. Cyclooxygenase 2 and inducible NO synthase were more expressed in the aortas of untreated SHRs compared with Wistar-Kyoto control rats; this pattern was normalized by both treatments. In conclusion, our data suggest that treatment with Pycnogenol and melatonin may protect the vasculature, partly independent of blood pressure reduction, probably through their antioxidant effects.

  2. Solving the small-scale structure puzzles with dissipative dark matter

    NASA Astrophysics Data System (ADS)

    Foot, Robert; Vagnozzi, Sunny

    2016-07-01

    Small-scale structure is studied in the context of dissipative dark matter, arising for instance in models with a hidden unbroken Abelian sector, so that dark matter couples to a massless dark photon. The dark sector interacts with ordinary matter via gravity and photon-dark photon kinetic mixing. Mirror dark matter is a theoretically constrained special case where all parameters are fixed except for the kinetic mixing strength, epsilon. In these models, the dark matter halo around spiral and irregular galaxies takes the form of a dissipative plasma which evolves in response to various heating and cooling processes. It has been argued previously that such dynamics can account for the inferred cored density profiles of galaxies and other related structural features. Here we focus on the apparent deficit of nearby small galaxies (``missing satellite problem"), which these dissipative models have the potential to address through small-scale power suppression by acoustic and diffusion damping. Using a variant of the extended Press-Schechter formalism, we evaluate the halo mass function for the special case of mirror dark matter. Considering a simplified model where Mbaryons propto Mhalo, we relate the halo mass function to more directly observable quantities, and find that for epsilon ≈ 2 × 10-10 such a simplified description is compatible with the measured galaxy luminosity and velocity functions. On scales Mhalo lesssim 108 Msolar, diffusion damping exponentially suppresses the halo mass function, suggesting a nonprimordial origin for dwarf spheroidal satellite galaxies, which we speculate were formed via a top-down fragmentation process as the result of nonlinear dissipative collapse of larger density perturbations. This could explain the planar orientation of satellite galaxies around Andromeda and the Milky Way.

  3. Structural study of a small molecule receptor bound to dimethyllysine in lysozyme

    PubMed Central

    McGovern, Róise E.; Snarr, Brendan D.; Lyons, Joseph A.; McFarlane, James; Whiting, Amanda L.; Paci, Irina; Hof, Fraser; Crowley, Peter B.

    2014-01-01

    Lysine is a ubiquitous residue on protein surfaces. Post translational modifications of lysine, including methylation to the mono-, di- or trimethylated amine result in chemical and structural alterations that have major consequences for protein interactions and signalling pathways. Small molecules that bind to methylated lysines are potential tools to modify such pathways. To make progress in this direction, detailed structural data of ligands in complex with methylated lysine is required. Here, we report a crystal structure of p-sulfonatocalix[4]arene (sclx4) bound to methylated lysozyme in which the lysine residues were chemically modified from Lys-NH3+ to Lys-NH(Me2)+. Of the six possible dimethyllysine sites, sclx4 selected Lys116-Me2 and the dimethylamino substituent was deeply buried in the calixarene cavity. This complex confirms the tendency for Lys-Me2 residues to form cation-π interactions, which have been shown to be important in protein recognition of histone tails bearing methylated lysines. Supporting data from NMR spectroscopy and MD simulations confirm the selectivity for Lys116-Me2 in solution. The structure presented here may serve as a stepping stone to the development of new biochemical reagents that target methylated lysines. PMID:25530835

  4. Small structures fabricated using ash-forming biological materials as templates.

    PubMed

    Kim, Youngbaek

    2003-01-01

    Different ash-forming biological materials such as gills of mushrooms, cotton wool, silk fiber, spider silk, dog's hair, and human hair were examined as templates to fabricate small structures. Ashes obtained from gills of mushrooms, silk fiber, and spider silk were miniaturized replicas of the original materials, whereas ashes from dog's hair and human hair were tubes. These materials were successfully coated with different inorganic materials by interface-selective sol-gel polymerization. Calcining coated materials yielded structures composed of ash and coated inorganic materials such as silica, titania, copper oxide, aluminum oxide, and iron oxide. Fully calcined ashes from native materials and materials coated with silica were usually 1/3 and 1/5 as large as their original materials, respectively. Silica-ash hybrid materials were much more rigid than ash materials. Incompletely calcined human hairs formed tubes with thick carbonized walls, and their inside morphologies suggested that medulla in human hairs might be responsible for tube formation. Preparation of complex tubular structures was possible as tied hairs did not break during calcination. Results in this study showed biological materials were useful as templates for fabricating inorganic structures regardless of ash formation.

  5. A Small-Animal Irradiation Facility for Neutron Capture Therapy Research at the RA-3 Research Reactor

    SciTech Connect

    Emiliano Pozzi; David W. Nigg; Marcelo Miller; Silvia I. Thorp; Amanda E. Schwint; Elisa M. Heber; Veronica A. Trivillin; Leandro Zarza; Guillermo Estryk

    2007-11-01

    The National Atomic Energy Commission of Argentina (CNEA) has constructed a thermal neutron source for use in Boron Neutron Capture Therapy (BNCT) applications at the RA-3 research reactor facility located in Buenos Aires. The Idaho National Laboratory (INL) and CNEA have jointly conducted some initial neutronic characterization measurements for one particular configuration of this source. The RA-3 reactor (Figure 1) is an open pool type reactor, with 20% enriched uranium plate-type fuel and light water coolant. A graphite thermal column is situated on one side of the reactor as shown. A tunnel penetrating the graphite structure enables the insertion of samples while the reactor is in normal operation. Samples up to 14 cm height and 15 cm width are accommodated.

  6. Strengthening Structured Abstracts for Education Research: The Need for Claim-Based Structured Abstracts

    ERIC Educational Resources Information Center

    Kelly, Anthony E.; Yin, Robert K.

    2007-01-01

    Recent policy recommendations involving the putative primacy of randomized clinical trials in educational settings have reignited research paradigm debates. The authors of this article use the vehicle of strengthening structured journal abstracts to point out the argumentative character of all education research claims. They offer suggestions to…

  7. Technique for Solving Electrically Small to Large Structures for Broadband Applications

    NASA Technical Reports Server (NTRS)

    Jandhyala, Vikram; Chowdhury, Indranil

    2011-01-01

    Fast iterative algorithms are often used for solving Method of Moments (MoM) systems, having a large number of unknowns, to determine current distribution and other parameters. The most commonly used fast methods include the fast multipole method (FMM), the precorrected fast Fourier transform (PFFT), and low-rank QR compression methods. These methods reduce the O(N) memory and time requirements to O(N log N) by compressing the dense MoM system so as to exploit the physics of Green s Function interactions. FFT-based techniques for solving such problems are efficient for spacefilling and uniform structures, but their performance substantially degrades for non-uniformly distributed structures due to the inherent need to employ a uniform global grid. FMM or QR techniques are better suited than FFT techniques; however, neither the FMM nor the QR technique can be used at all frequencies. This method has been developed to efficiently solve for a desired parameter of a system or device that can include both electrically large FMM elements, and electrically small QR elements. The system or device is set up as an oct-tree structure that can include regions of both the FMM type and the QR type. The system is enclosed with a cube at a 0- th level, splitting the cube at the 0-th level into eight child cubes. This forms cubes at a 1st level, recursively repeating the splitting process for cubes at successive levels until a desired number of levels is created. For each cube that is thus formed, neighbor lists and interaction lists are maintained. An iterative solver is then used to determine a first matrix vector product for any electrically large elements as well as a second matrix vector product for any electrically small elements that are included in the structure. These matrix vector products for the electrically large and small elements are combined, and a net delta for a combination of the matrix vector products is determined. The iteration continues until a net delta is

  8. Consistent structures and interactions by density functional theory with small atomic orbital basis sets.

    PubMed

    Grimme, Stefan; Brandenburg, Jan Gerit; Bannwarth, Christoph; Hansen, Andreas

    2015-08-07

    A density functional theory (DFT) based composite electronic structure approach is proposed to efficiently compute structures and interaction energies in large chemical systems. It is based on the well-known and numerically robust Perdew-Burke-Ernzerhoff (PBE) generalized-gradient-approximation in a modified global hybrid functional with a relatively large amount of non-local Fock-exchange. The orbitals are expanded in Ahlrichs-type valence-double zeta atomic orbital (AO) Gaussian basis sets, which are available for many elements. In order to correct for the basis set superposition error (BSSE) and to account for the important long-range London dispersion effects, our well-established atom-pairwise potentials are used. In the design of the new method, particular attention has been paid to an accurate description of structural parameters in various covalent and non-covalent bonding situations as well as in periodic systems. Together with the recently proposed three-fold corrected (3c) Hartree-Fock method, the new composite scheme (termed PBEh-3c) represents the next member in a hierarchy of "low-cost" electronic structure approaches. They are mainly free of BSSE and account for most interactions in a physically sound and asymptotically correct manner. PBEh-3c yields good results for thermochemical properties in the huge GMTKN30 energy database. Furthermore, the method shows excellent performance for non-covalent interaction energies in small and large complexes. For evaluating its performance on equilibrium structures, a new compilation of standard test sets is suggested. These consist of small (light) molecules, partially flexible, medium-sized organic molecules, molecules comprising heavy main group elements, larger systems with long bonds, 3d-transition metal systems, non-covalently bound complexes (S22 and S66×8 sets), and peptide conformations. For these sets, overall deviations from accurate reference data are smaller than for various other tested DFT methods

  9. Consistent structures and interactions by density functional theory with small atomic orbital basis sets

    NASA Astrophysics Data System (ADS)

    Grimme, Stefan; Brandenburg, Jan Gerit; Bannwarth, Christoph; Hansen, Andreas

    2015-08-01

    A density functional theory (DFT) based composite electronic structure approach is proposed to efficiently compute structures and interaction energies in large chemical systems. It is based on the well-known and numerically robust Perdew-Burke-Ernzerhoff (PBE) generalized-gradient-approximation in a modified global hybrid functional with a relatively large amount of non-local Fock-exchange. The orbitals are expanded in Ahlrichs-type valence-double zeta atomic orbital (AO) Gaussian basis sets, which are available for many elements. In order to correct for the basis set superposition error (BSSE) and to account for the important long-range London dispersion effects, our well-established atom-pairwise potentials are used. In the design of the new method, particular attention has been paid to an accurate description of structural parameters in various covalent and non-covalent bonding situations as well as in periodic systems. Together with the recently proposed three-fold corrected (3c) Hartree-Fock method, the new composite scheme (termed PBEh-3c) represents the next member in a hierarchy of "low-cost" electronic structure approaches. They are mainly free of BSSE and account for most interactions in a physically sound and asymptotically correct manner. PBEh-3c yields good results for thermochemical properties in the huge GMTKN30 energy database. Furthermore, the method shows excellent performance for non-covalent interaction energies in small and large complexes. For evaluating its performance on equilibrium structures, a new compilation of standard test sets is suggested. These consist of small (light) molecules, partially flexible, medium-sized organic molecules, molecules comprising heavy main group elements, larger systems with long bonds, 3d-transition metal systems, non-covalently bound complexes (S22 and S66×8 sets), and peptide conformations. For these sets, overall deviations from accurate reference data are smaller than for various other tested DFT methods

  10. Consistent structures and interactions by density functional theory with small atomic orbital basis sets

    SciTech Connect

    Grimme, Stefan Brandenburg, Jan Gerit; Bannwarth, Christoph; Hansen, Andreas

    2015-08-07

    A density functional theory (DFT) based composite electronic structure approach is proposed to efficiently compute structures and interaction energies in large chemical systems. It is based on the well-known and numerically robust Perdew-Burke-Ernzerhoff (PBE) generalized-gradient-approximation in a modified global hybrid functional with a relatively large amount of non-local Fock-exchange. The orbitals are expanded in Ahlrichs-type valence-double zeta atomic orbital (AO) Gaussian basis sets, which are available for many elements. In order to correct for the basis set superposition error (BSSE) and to account for the important long-range London dispersion effects, our well-established atom-pairwise potentials are used. In the design of the new method, particular attention has been paid to an accurate description of structural parameters in various covalent and non-covalent bonding situations as well as in periodic systems. Together with the recently proposed three-fold corrected (3c) Hartree-Fock method, the new composite scheme (termed PBEh-3c) represents the next member in a hierarchy of “low-cost” electronic structure approaches. They are mainly free of BSSE and account for most interactions in a physically sound and asymptotically correct manner. PBEh-3c yields good results for thermochemical properties in the huge GMTKN30 energy database. Furthermore, the method shows excellent performance for non-covalent interaction energies in small and large complexes. For evaluating its performance on equilibrium structures, a new compilation of standard test sets is suggested. These consist of small (light) molecules, partially flexible, medium-sized organic molecules, molecules comprising heavy main group elements, larger systems with long bonds, 3d-transition metal systems, non-covalently bound complexes (S22 and S66×8 sets), and peptide conformations. For these sets, overall deviations from accurate reference data are smaller than for various other tested DFT

  11. Electronic structure of SnxGe1-x alloys for small Sn compositions: Unusual structural and electronic properties

    NASA Astrophysics Data System (ADS)

    Chibane, Y.; Ferhat, M.

    2010-03-01

    The full potential augmented plane wave plus local orbital method using the local density approximation within the framework of density functional theory is applied to investigate structural, electronic, and thermodynamic properties of SnxGe1-x alloys for small Sn compositions (x =0.0625, 0.125, 0.1875, and 0.25). For the structural properties, we found strong deviation from Vegard's law for the variation in the lattice parameter, moreover, this deviation is found positive as found experimentally. This feature is in direct contrast with conventional IV-IV alloys, were the deviation of the variation in the lattice parameter from Vegard's law is generally weak and negative. The calculated bond lengths of Sn-Ge, also show significant departures of bond lengths from the virtual crystal approximation (VCA). The calculations confirm a strong band gap reduction in Ge. For small Sn incorporation, the calculated optical band gap bowing (i.e., bowing of the direct band gap) is found strongly composition dependent. For small Sn composition (x =0.0625), we found a strong optical band gap bowing of 2.9 eV, in very good agreement with the measured values at low Sn composition of 2.8 eV of [He and Atwater, Phys. Rev. Lett. 79, 1937 (1997)] and 2.84 eV of Pérez Ladrón de Guevara et al. [Appl. Phys. Lett. 91, 161909 (2007)]. For small composition regime (0

  12. Using Service-Learning Projects to Jump Start Research at Small Institutions

    NASA Astrophysics Data System (ADS)

    Ongley, L. K.; Spigel, K.; Olin, J.

    2010-12-01

    Geoscientists at small institutions must frequently be very creative about funding and conducting research. High teaching loads, tuition-driven budgets, and a dearth of geosciences colleagues all contribute challenges to an intellectual life that includes research as a scholarship endeavor. Fortunately, service-learning can be used as a multi-purpose pedagogical technique. Unity College is a very small environmentally-focused undergraduate institution in rural Maine with a student population of less than 600 students. Our students really appreciate learning in the field and through participation in projects that impact the communities in which they live and study. Our Environmental Science (geosciences) and Environmental Analysis (chemistry) majors have been showing increasing interest in pursuing graduate school and independent projects in greater and greater depth. In the past 5 years we have had a complete turn-over in geoscience and chemistry faculty (2 persons), a shift that has brought new ideas to campus and a different idea about importance of research. Unity College has always been a big proponent of community-based projects so the extension to service learning as a pedagogical technique has been smooth. A wide variety of towns, schools, land trusts, pond associations and other groups approach Unity College with project ideas. We are best equipped to handle suggestions that relate to environmental chemistry and to lake sedimentation owing to the research interests of our geoscience faculty. We present two examples of ways to sequence student work that ultimately end in student/faculty research projects. Sophomores in the Unity College Environmental Stewardship Core curriculum may choose to take a course that introduces lake sedimentation as a tool to study environmental change. Students in the course take several sediment cores to analyze proxies of environmental change to reconstruct past environments. The final results are reported to the community

  13. Research on small signal detection of optical voltage/current transformer

    NASA Astrophysics Data System (ADS)

    Li, Hongbo; Zhang, Guoqing; Cai, Xingguo; Guo, Zhizhong; Yu, Wenbin; Huo, Guangyu

    2013-08-01

    This paper researches the signal conditioning program of optical voltage/current transformer and the imbalance during the transmission of dual optical path, gives a brief introduction to the basic principle of optical voltage transformer based on electro-optic Pockels effect and optical current transformer based on Faraday Magnetic-optical Effect, and induces a general expression form of output light intensities This paper research on the signal modulation methods for the system: AC and DC modulations. What is more, the advantages and disadvantages of both modulations in the system will be analyzed. Considering the characteristics that the systematic noise and signal have the spectrum overlapping and that when there is any fault, the fact that in the small signal detection system the output SNR of AC modulation is better than that of DC modulation will be proved. For the parameter changes caused by the environment factors, the feedback control linked by the DSP is imported, it automatically adjusts the balance of the two branch parameters, acquires the measured component in the condition of the two branch unbalance parameters. Furthermore, this paper researches on the influence of imbalance of the dual optical path on the signal detection system. It analyzes the error characteristics due to different kinds of losses and to component matching disorders and other intrinsic factors and then put forward the method to calculate balancing factors by means of the RMS of 50Hz signal. The result proves that using this method can improve the output SNR of optical voltage/current transformer to some extent.

  14. A high resolution small animal radiation research platform (SARRP) with x-ray tomographic guidance capabilities

    PubMed Central

    Wong, John; Armour, Elwood; Kazanzides, Peter; Iordachita, Iulian; Tryggestad, Erik; Deng, Hua; Matinfar, Mohammad; Kennedy, Christopher; Liu, Zejian; Chan, Timothy; Gray, Owen; Verhaegen, Frank; McNutt, Todd; Ford, Eric; DeWeese, Theodore L.

    2008-01-01

    Purpose To demonstrate the CT imaging, conformal irradiation and treatment planning capabilities of a small animal radiation research platform (SARRP). Methods The SARRP employs a dual-focal spot, constant voltage x-ray source mounted on a gantry with a source-to-isocenter distance of 35 cm. Gantry rotation is limited to 120° from vertical. Eighty to 100 kVp x-rays from the smaller 0.4 mm focal spot are used for imaging. Both 0.4 mm and 3.0 mm focal spots operate at 225 kVp for irradiation. Robotic translate/rotate stages are used to position the animal. Cone-beam (CB) CT imaging is achieved by rotating the horizontal animal between the stationary x-ray source and a flat-panel detector. Radiation beams range from 0.5 mm in diameter to (60 × 60) mm2. Dosimetry is measured with radio-chromic films. Monte Carlo dose calculations are employed for treatment planning. The combination of gantry and robotic stage motions facilitate conformal irradiation. Results The SARRP spans 3 ft × 4 ft × 6 ft (WxLxH). Depending on filtration, the isocenter dose outputs at 1 cm depth in water range from 22 to 375 cGy/min from the smallest to the largest radiation fields. The 20% to 80% dose fall-off spans 0.16 mm. CBCT with (0.6 × 0.6 × 0.6) mm3 voxel resolution is acquired with less than 1 cGy. Treatment planning is performed at sub-mm resolution. Conclusions The capability of the SARRP to deliver highly focal beams to multiple animal model systems provides new research opportunities that more realistically bridge laboratory research and clinical translation. PMID:18640502

  15. Small Angle Neutron-Scattering Studies of the Core Structure of Intact Neurosecretory Vesicles.

    NASA Astrophysics Data System (ADS)

    Krueger, Susan Takacs

    Small angle neutron scattering (SANS) was used to study the state of the dense cores within intact neurosecretory vesicles. These vesicles transport the neurophysin proteins, along with their associated hormones, oxytocin or vasopressin, from the posterior pituitary gland to the bloodstream, where the entire vesicle contents are released. Knowledge of the vesicle core structure is important in developing an understanding of this release mechanism. Since the core constituents exist in a dense state at concentrations which cannot be reproduced (in solution) in the laboratory, a new method was developed to determine the core structure from SANS experiments performed on intact neurosecretory vesicles. These studies were complemented by biochemical assays performed to determine the role, if any, played by phospholipids in the interactions between the core constituents. H_2O/D_2 O ratio in the solvent can be adjusted, using the method of contrast variation, such that the scattering due to the vesicle membranes is minimized, thus emphasizing the scattering originating from the cores. The applicability of this method for examining the interior of biological vesicles was tested by performing an initial study on human red blood cells, which are similar in structure to other biological vesicles. Changes in intermolecular hemoglobin interactions, occurring when the ionic strength of the solvent was varied or when the cells were deoxygenated, were examined. The results agreed with those expected for dense protein solutions, indicating that the method developed was suitable for the study of hemoglobin within the cells. Similar SANS studies were then performed on intact neurosecretory vesicles. The experimental results were inconsistent with model calculations which assumed that the cores consisted of small, densely-packed particles or large, globular aggregates. Although a unique model could not be determined, the data suggest that the core constituents form long aggregates of

  16. Structure-Function Correlation of G6, a Novel Small Molecule Inhibitor of Jak2

    PubMed Central

    Majumder, Anurima; Govindasamy, Lakshmanan; Magis, Andrew; Kiss, Róbert; Polgár, Tímea; Baskin, Rebekah; Allan, Robert W.; Agbandje-McKenna, Mavis; Reuther, Gary W.; Keserű, György M.; Bisht, Kirpal S.; Sayeski, Peter P.

    2010-01-01

    Somatic mutations in the Jak2 protein, such as V617F, cause aberrant Jak/STAT signaling and can lead to the development of myeloproliferative neoplasms. This discovery has led to the search for small molecule inhibitors that target Jak2. Using structure-based virtual screening, our group recently identified a novel small molecule inhibitor of Jak2 named G6. Here, we identified a structure-function correlation of this compound. Specifically, five derivative compounds of G6 having structural similarity to the original lead compound were obtained and analyzed for their ability to (i) inhibit Jak2-V617F-mediated cell growth, (ii) inhibit the levels of phospho-Jak2, phospho-STAT3, and phospho-STAT5; (iii) induce apoptosis in human erythroleukemia cells; and (iv) suppress pathologic cell growth of Jak2-V617F-expressing human bone marrow cells ex vivo. Additionally, we computationally examined the interactions of these compounds with the ATP-binding pocket of the Jak2 kinase domain. We found that the stilbenoid core-containing derivatives of G6 significantly inhibited Jak2-V617F-mediated cell proliferation in a time- and dose-dependent manner. They also inhibited phosphorylation of Jak2, STAT3, and STAT5 proteins within cells, resulting in higher levels of apoptosis via the intrinsic apoptotic pathway. Finally, the stilbenoid derivatives inhibited the pathologic growth of Jak2-V617F-expressing human bone marrow cells ex vivo. Collectively, our data demonstrate that G6 has a stilbenoid core that is indispensable for maintaining its Jak2 inhibitory potential. PMID:20667821

  17. Small Business Innovation Research GRC Phase I, Phase II, and Post-Phase II Opportunity Assessment for 2015

    NASA Technical Reports Server (NTRS)

    Nguyen, Hung D.; Steele, Gynelle C.

    2016-01-01

    This report outlines the 2015 Small Business Innovation Research/Small Business Technology Transfer (SBIR/STTR) Phase I, Phase II, and Post-Phase II opportunity contract award results associated with NASA's Aeronautics Research Mission Directorate (ARMD), Human Exploration and Operations Mission Directorate (HEOMD), Science Mission Directorate (SMD), and Space Technology Mission Directorate (STMD) for NASA Glenn Research Center. The report also highlights the number of Phase I, Phase II, and Post-Phase II contracts awarded by mission directorate. The 2015 Phase I contract awards to companies in Ohio and their corresponding technologies are also discussed.

  18. Structure, Dynamics, and Thermodynamics of Small Molecules Adsorbed in Zeolite Micropores: Simulation and Statistical Mechanics.

    NASA Astrophysics Data System (ADS)

    van Tassel, Paul Robert

    1993-01-01

    This thesis describes a fully detailed molecular simulation and modeling effort aimed at understanding the fundamentals of adsorption and diffusion of small molecules in zeolite micropores. The primary emphasis is on determining the relationship between the structure and chemistry of the zeolite adsorbent and the structure, dynamics, and thermodynamics of the adsorbed phase. Further emphasis is on developing simple, predictive models of zeolite adsorption and diffusion. We begin by presenting a Monte Carlo simulation of single component adsorption of xenon, methane, and argon in zeolite NaA. The form of the adsorbate density distribution indicates the presence of discrete adsorption sites which arrange in polyhedra whose geometry depends on the number and position of zeolite framework ions. Isotherm plateaus are attributed to either (i) a low energy adsorbate configuration or (ii) the saturation of polyhedral sites. Viewing the adsorbed phase as an ordered arrangement differs from the conventional delocalized model, yet it helps explain certain experimental observations. Next, a study of binary mixtures of small molecules in zeolite NaA using the Monte Carlo method is presented. The mixing in the pore is determined to be highly nonideal by comparison to a simple pore volume filling model. Strong selectivity for a more polarizable molecule (xenon) is observed only at low pore loading. At higher pore loading, a smaller, less polarizable molecule (argon) adsorbs selectively at a significantly lower pressure than predicted by the model. This enhanced selectivity is due to the ability of the smaller molecule to pack more efficiently inside of the pore. Finally, we present two simple lattice models whose forms are arrived at following careful consideration of simulation results. The first describes the adsorption of small molecules in a zeolite. A polyhedral lattice is postulated whose neighboring sites interact energetically and entropically. The second model describes

  19. Probing small-scale structure in galaxies with strong gravitational lensing

    NASA Astrophysics Data System (ADS)

    Congdon, Arthur Benjamin

    We use gravitational lensing to study the small-scale distribution of matter in galaxies. First, we examine galaxies and their dark matter halos. Roughly half of all observed four-image quasar lenses have image flux ratios that differ from the values predicted by simple lens potentials. We show that smooth departures from elliptical symmetry fail to explain anomalous radio fluxes, strengthening the case for dark matter substructure. Our results have important implications for the "missing satellites'' problem. We then consider how time delays between lensed images can be used to identify lens galaxies containing small-scale structure. We derive an analytic relation for the time delay between the close pair of images in a "fold'' lens, and perform Monte Carlo simulations to investigate the utility of time delays for probing small- scale structure in realistic lens populations. We compare our numerical predictions with systems that have measured time delays and discover two anomalous lenses. Next, we consider microlensing, where stars in the lens galaxy perturb image magnifications. This is relevant at optical wavelengths, where the size of the lensed source is comparable to the Einstein radius of a typical star. Our simulations of negative-parity images show that raising the fraction of dark matter relative to stars increases image flux variability for small sources, and decreases it for large sources. This suggests that quasar accretion disks and broad-emission-line regions may respond differently to microlensing. We also consider extended sources with a range of ellipticities, which has relevance to a population of inclined accretion disks. Depending on their orientation, more elongated sources lead to more rapid variability, which may complicate the interpretation of microlensing light curves. Finally, we consider prospects for observing strong lensing by the supermassive black hole at the center of the Milky Way, Sgr A*. Assuming a black hole on the million

  20. Effect of the small-world structure on encoding performance in the primary visual cortex: an electrophysiological and modeling analysis.

    PubMed

    Shi, Li; Niu, Xiaoke; Wan, Hong

    2015-05-01

    The biological networks have been widely reported to present small-world properties. However, the effects of small-world network structure on population's encoding performance remain poorly understood. To address this issue, we applied a small world-based framework to quantify and analyze the response dynamics of cell assemblies recorded from rat primary visual cortex, and further established a population encoding model based on small world-based generalized linear model (SW-GLM). The electrophysiological experimental results show that the small world-based population responses to different topological shapes present significant variation (t test, p < 0.01; effect size: Hedge's g > 0.8), while no significant variation was found for control networks without considering their spatial connectivity (t test, p > 0.05; effect size: Hedge's g < 0.5). Furthermore, the numerical experimental results show that the predicted response under SW-GLM is more accurate and reliable compared to the control model without small-world structure, and the decoding performance is also improved about 10 % by taking the small-world structure into account. The above results suggest the important role of the small-world neural structure in encoding visual information for the neural population by providing electrophysiological and theoretical evidence, respectively. The study helps greatly to well understand the population encoding mechanisms of visual cortex.

  1. Disproportionate effects of non-colonial small herbivores on structure and diversity of grassland dominated by large herbivores

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The response of semiarid grasslands to small, non-colonial herbivores has received little attention, focusing primarily on the effects of granivore assemblages on annual plant communities. We studied the long-term effects of small and large herbivores on vegetation structure and species diversity of...

  2. Big Atoms for Small Children: Building Atomic Models from Common Materials to Better Visualize and Conceptualize Atomic Structure

    ERIC Educational Resources Information Center

    Cipolla, Laura; Ferrari, Lia A.

    2016-01-01

    A hands-on approach to introduce the chemical elements and the atomic structure to elementary/middle school students is described. The proposed classroom activity presents Bohr models of atoms using common and inexpensive materials, such as nested plastic balls, colored modeling clay, and small-sized pasta (or small plastic beads).

  3. Monitoring and modeling for radon entry into basements: A status report for the small structures project

    SciTech Connect

    Fisk, W.J.; Flexser, S.; Gadgil, A.J.; Holman, H.Y.; Modera, M.P.; Narasimhan, T.N.; Nuzum, T.; Revzan, K.L.; Sextro, R.G.; Smith, A.R.

    1989-09-01

    The approach, status, and initial findings of a research project on radon transport through soil and entry into buildings are described. We have constructed two room-size precisely-fabricated basements at a site with relatively homogeneous soil. The structures have adjustable-size openings to the soil, are otherwise very air-tight, and are mechanically ventilated using a system that also controls the indoor-outdoor pressure difference. Numerous probes have been installed in the soil surrounding the structures to permit multipoint measurement of soil moisture content, soil temperature, permeability of soil to air, soil-gas pressure and radon concentration. State-of-the-art instrumentation is being installed for real-time monitoring of these parameters plus structure ventilation rate, indoor and entering soil-gas radon concentrations, and meteorologic parameters for a period of at least one year. Many of the factors that control or influence radon entry will be modified intentionally or by changes in environmental parameters during the course of the measurements. We have found it necessary to design and fabricate a new type of probe for more accurate measurements of soil permeability. We have also verified and improved procedures for more accurate, rapid, multipoint measurements of radon concentrations using a continuous radon monitor. Identical structures, with the same instrumentation, will be constructed at additional sites with difference soil characteristics and climates. Core samples of the soil from each site are analyzed to determine density, porosity, permeability, radium content, and radon emmanation coefficient. The research project also includes steady-state and transient numerical modeling efforts that complement the experimental research and that will use the experimental data for model validation. 32 refs., 12 figs., 5 tabs.

  4. Self-monitoring surveillance system for prestressing tendons. Phase I small business innovation research

    SciTech Connect

    Tabatabai, H.

    1995-12-01

    Assured safety and operational reliability of post-tensioned concrete components of nuclear power plants are of great significance to the public, electric utilities, and regulatory agencies. Prestressing tendons provide principal reinforcement for containment and other structures. In this phase of the research effort, the feasibility of developing a passive surveillance system for identification of ruptures in tendon wires was evaluated and verified. The concept offers high potential for greatly increasing effectiveness of presently-utilized periodic tendon condition surveillance programs. A one-tenth scale ring model of the Palo Verde nuclear containment structure was built inside the Structural Laboratory. Dynamic scaling (similitude) relationships were used to relate measured sensor responses recorded during controlled wire breakages to the expected prototype containment tendon response. Strong and recognizable signatures were detected by the accelerometers used. It was concluded that the unbonded prestressing tendons provide an excellent path for transmission of stress waves resulting from wire breaks. Accelerometers placed directly on the bearing plates at the ends of tendons recorded high-intensity waveforms. Accelerometers placed elsewhere on concrete surfaces of the containment model revealed substantial attenuation and reduced intensities of captured waveforms. Locations of wire breaks could be determined accurately through measurement of differences in arrival times of the signal at the sensors. Pattern recognition systems to be utilized in conjunction with the proposed concept will provide a basis for an integrated and automated tool for identification of wire breaks.

  5. Uncertainty analysis of practical structural health monitoring systems currently employed for tall buildings consisting of small number of sensors

    NASA Astrophysics Data System (ADS)

    Hirai, Kenta; Mita, Akira

    2016-04-01

    Because of social background, such as repeated large earthquakes and cheating in design and construction, structural health monitoring (SHM) systems are getting strong attention. The SHM systems are in a practical phase. An SHM system consisting of small number of sensors has been introduced to 6 tall buildings in Shinjuku area. Including them, there are 2 major issues in the SHM systems consisting of small number of sensors. First, optimal system number of sensors and the location are not well-defined. In the practice, system placement is determined based on rough prediction and experience. Second, there are some uncertainties in estimation results by the SHM systems. Thus, the purpose of this research is to provide useful information for increasing reliability of SHM system and to improve estimation results based on uncertainty analysis of the SHM systems. The important damage index used here is the inter-story drift angle. The uncertainty considered here are number of sensors, earthquake motion characteristics, noise in data, error between numerical model and real building, nonlinearity of parameter. Then I have analyzed influence of each factor to estimation accuracy. The analysis conducted here will help to decide sensor system design considering valance of cost and accuracy. Because of constraint on the number of sensors, estimation results by the SHM system has tendency to provide smaller values. To overcome this problem, a compensation algorithm was discussed and presented. The usefulness of this compensation method was demonstrated for 40 story S and RC building models with nonlinear response.

  6. Temperature-compensated strain measurement of full-scale small aircraft wing structure using low-cost FBG interrogator

    NASA Astrophysics Data System (ADS)

    Kim, J. H.; Lee, Y. G.; Park, Y.; Kim, C. G.

    2013-04-01

    Recently, health and usage monitoring systems (HUMS) are being studied to monitor the real-time condition of aircrafts during flight. HUMSs can prevent aircraft accidents and reduce inspection time and cost. Fiber Bragg grating (FBG) sensors are widely used for aircraft HUMSs with many advantages such as light weight, small size, easy-multiplexing, and EMI immunity. However, commercial FBG interrogators are too expensive to apply for small aircrafts. Generally the cost of conventional FBG interrogators is over 20,000. Therefore, cost-effective FBG interrogation systems need to be developed for small aircraft HUMSs. In this study, cost-effective low speed FBG interrogator was applied to full-scale small aircraft wing structure to examine the operational applicability of the low speed FBG interrogator to the monitoring of small aircrafts. The cost of the developed low speed FBG interrogator was about 10,000, which is an affordable price for a small aircraft. 10 FBG strain sensors and 1 FBG temperature sensor were installed on the surface of the full-scale wing structure. Load was applied to the tip of the wing structure, and the low speed interrogator detected the change in the center wavelength of the FBG sensors at the sampling rate of 10Hz. To assess the applicability of the low-cost FBG interrogator to full-scale small aircraft wing structure, a temperature-compensated strain measurement algorithm was verified experimentally under various loading conditions of the wing structure with temperature variations.

  7. Application of X-ray and neutron small angle scattering techniques to study the hierarchical structure of plant cell walls: a review.

    PubMed

    Martínez-Sanz, Marta; Gidley, Michael J; Gilbert, Elliot P

    2015-07-10

    Plant cell walls present an extremely complex structure of hierarchically assembled cellulose microfibrils embedded in a multi-component matrix. The biosynthesis process determines the mechanism of cellulose crystallisation and assembly, as well as the interaction of cellulose with other cell wall components. Thus, a knowledge of cellulose microfibril and bundle architecture, and the structural role of matrix components, is crucial for understanding cell wall functional and technological roles. Small angle scattering techniques, combined with complementary methods, provide an efficient approach to characterise plant cell walls, covering a broad and relevant size range while minimising experimental artefacts derived from sample treatment. Given the system complexity, approaches such as component extraction and the use of plant cell wall analogues are typically employed to enable the interpretation of experimental results. This review summarises the current research status on the characterisation of the hierarchical structure of plant cell walls using small angle scattering techniques.

  8. Status of research aimed at predicting structural integrity

    SciTech Connect

    Reuter, W.G.

    1997-12-31

    Considerable research has been performed throughout the world on measuring the fracture toughness of metals. The existing capability fills the need encountered when selecting materials, thermal-mechanical treatments, welding procedures, etc., but cannot predict the fracture process of structural components containing cracks. The Idaho National Engineering and Environmental Laboratory and the Massachusetts Institute of Technology have been collaborating for a number of years on developing capabilities for using fracture toughness results to predict structural integrity. Because of the high cost of fabricating and testing structural components, these studies have been limited to predicting the fracture process in specimens containing surface cracks. This paper summarizes the present status of the experimental studies of using fracture toughness data to predict crack growth initiation in specimens (structural components) containing surface cracks. These results are limited to homogeneous base materials.

  9. Comparative analysis of the nucleosome structure of cell nuclei by small-angle neutron scattering

    NASA Astrophysics Data System (ADS)

    Isaev-Ivanov, V. V.; Lebedev, D. V.; Lauter, H.; Pantina, R. A.; Kuklin, A. I.; Islamov, A. Kh.; Filatov, M. V.

    2010-05-01

    The nucleosome structure in native nuclei of normal (chicken erythrocyte and rat leukocyte nuclei) and anomalously proliferating (the human cervical adenocarcinoma cell line HeLa and the Chinese hamster fibroblast cell line A238) cells has been investigated using small-angle neutron scattering. The experimental results obtained allow one to make the inference that the parameters of the nucleosome structure for the chicken erythrocyte and rat leukocyte nuclei (on average over the nucleus) are close to the universally accepted values and that the distance distribution function is bimodal. The bimodality of the distance distribution function reflects a narrow distribution of distances between nucleosomes (on average over the nucleus) at the fibril level of the chromatin organization. The histone core of the nucleosome structure in the nuclei of the HeLa and A238 cells (on average over the nucleus) is considerably less compact than that in the chicken erythrocyte and rat leukocyte nuclei, and the distance distribution function does not exhibit indications of the bimodality.

  10. Integrative structural analysis of the UTPB complex, an early assembly factor for eukaryotic small ribosomal subunits.

    PubMed

    Zhang, Cheng; Sun, Qi; Chen, Rongchang; Chen, Xining; Lin, Jinzhong; Ye, Keqiong

    2016-09-06

    Ribosome assembly is an essential and conserved cellular process in eukaryotes that requires numerous assembly factors. The six-subunit UTPB complex is an essential component of the 90S precursor of the small ribosomal subunit. Here, we analyzed the molecular architecture of UTPB using an integrative structural biology approach. We mapped the major interactions that associate each of six UTPB proteins. Crystallographic studies showed that Utp1, Utp21, Utp12 and Utp13 are evolutionarily related and form a dimer of dimers (Utp1-Utp21, Utp12-Utp13) through their homologous helical C-terminal domains. Molecular docking with crosslinking restraints showed that the WD domains of Utp12 and Utp13 are associated, as are the WD domains of Utp1, Utp21 and Utp18. Electron microscopy images of the entire UTPB complex revealed that it predominantly adopts elongated conformations and possesses internal flexibility. We also determined crystal structures of the WD domain of Utp18 and the HAT and deviant HAT domains of Utp6. A structural model of UTPB was derived based on these data.

  11. Barrierless evolution of structure during the submillisecond refolding reaction of a small protein

    PubMed Central

    Sinha, Kalyan K.; Udgaonkar, Jayant B.

    2008-01-01

    To determine whether a protein folding reaction can occur in the absence of a dominant barrier is crucial for understanding its complexity. Here direct ultrafast kinetic measurements have been used to study the initial submillisecond (sub-ms) folding reaction of the small protein barstar. The cooperativity of the initial folding reaction has been explored by using two probes: fluorescence resonance energy transfer, through which the contraction of two intramolecular distances is measured, and the binding of 8-anilino-1-naphthalene sulfonic acid, through which the formation of hydrophobic clusters is monitored. A fast chain contraction is shown to precede the formation of hydrophobic clusters, indicating that the sub-ms folding reaction is not cooperative. The observed rate constant of the sub-ms folding reaction monitored by 8-anilino-1-naphthalene sulfonic acid fluorescence has been found to be the same in stabilizing conditions (low urea concentrations), in which specific structure is formed, and in marginally stabilizing conditions (higher urea concentrations), where virtually no structure is formed in the product of the sub-ms folding reaction. The observation that the folding rate is independent of the folding conditions suggests that the initial folding reaction occurs in the absence of a dominant free energy barrier. These results provide kinetic evidence that the formation of specific structure need not be slowed down by any significant free energy barrier during the course of a very fast protein folding reaction. PMID:18523007

  12. Formation of a small impact structure discovered within the Agoudal meteorite strewn field, Morocco

    NASA Astrophysics Data System (ADS)

    Lorenz, C. A.; Ivanova, M. A.; Artemieva, N. A.; Sadilenko, D. A.; Chennaoui Aoudjehane, H.; Roschina, I. A.; Korochantsev, A. V.; Humayun, M.

    2015-01-01

    A relic impact structure was recognized within the strewn field of the Agoudal iron meteorite. The heavily eroded structure has preserved shatter cones in a limestone basement, and remnants of autochthonous and allochthonous breccias. Fragments of iron incorporated into the allochthonous breccia have a chemical composition (Ni = 5.16 wt%, Ir = 0.019 ppm) similar to that of the Agoudal meteorite, supporting a syngenetic origin of the strewn field and the impact structure. The total recovered mass of Agoudal meteorite fragments is estimated at approximately 500 kg. The estimated size of the SE-NW-oriented strewn field is 6 × 2 km. Model calculations with minimal preatmospheric size show that a similar meteorite strewn field plus one small crater with observed shock effects could be formed by fragmentation of a meteoroid approximately 1.4 m in diameter with an impact angle of approximately 60° from the horizontal. However, the most probable is an impact of a larger, 3-4 m diameter meteoroid, resulting a strewn field with approximately 10 craters, 10-30 m in diameter each, plus numerous meteorite fragments. The calculated scattering area of meteorite shrapnel ejected from these impact craters could completely cover the observed strewn field of the Agoudal meteorite.

  13. A study of large, medium and small scale structures in the topside ionosphere

    NASA Technical Reports Server (NTRS)

    Gross, Stanley H.; Kuo, Spencer P.; Shmoys, Jerry

    1986-01-01

    Alouette and ISIS data were studied for large, medium, and small scale structures in the ionosphere. Correlation was also sought with measurements by other satellites, such as the Atmosphere Explorer C and E and the Dynamic Explorer 2 satellites, of both neutrals and ionization, and with measurements by ground facilities, such as the incoherent scatter radars. Large scale coherent wavelike structures were found from ISIS 2 electron density contours from above the F peak to nearly the satellite altitude. Such structures were also found to correlate with the observation by AE-C below the F peak during a conjunction of the two satellites. Vertical wavefronts found in the upper F region suggest the dominance of diffusion along field lines as well. Also discovered were multiple, evenly spaced field-aligned ducts in the F region that, at low latitudes, extended to the other hemisphere and were in the form of field-aligned sheets in the east-west direction. Low latitude heating events were discovered that could serve as sources for waves in the ionosphere.

  14. Research and Development of a Small-Scale Adsorption Cooling System

    NASA Astrophysics Data System (ADS)

    Gupta, Yeshpal

    The world is grappling with two serious issues related to energy and climate change. The use of solar energy is receiving much attention due to its potential as one of the solutions. Air conditioning is particularly attractive as a solar energy application because of the near coincidence of peak cooling loads with the available solar power. Recently, researchers have started serious discussions of using adsorptive processes for refrigeration and heat pumps. There is some success for the >100 ton adsorption systems but none exists in the <10 ton size range required for residential air conditioning. There are myriad reasons for the lack of small-scale systems such as low Coefficient of Performance (COP), high capital cost, scalability, and limited performance data. A numerical model to simulate an adsorption system was developed and its performance was compared with similar thermal-powered systems. Results showed that both the adsorption and absorption systems provide equal cooling capacity for a driving temperature range of 70--120 ºC, but the adsorption system is the only system to deliver cooling at temperatures below 65 ºC. Additionally, the absorption and desiccant systems provide better COP at low temperatures, but the COP's of the three systems converge at higher regeneration temperatures. To further investigate the viability of solar-powered heat pump systems, an hourly building load simulation was developed for a single-family house in the Phoenix metropolitan area. Thermal as well as economic performance comparison was conducted for adsorption, absorption, and solar photovoltaic (PV) powered vapor compression systems for a range of solar collector area and storage capacity. The results showed that for a small collector area, solar PV is more cost-effective whereas adsorption is better than absorption for larger collector area. The optimum solar collector area and the storage size were determined for each type of solar system. As part of this dissertation

  15. Structure-based design of small peptide inhibitors of protein kinase CK2 subunit interaction

    PubMed Central

    Laudet, Béatrice; Barette, Caroline; Dulery, Vincent; Renaudet, Olivier; Dumy, Pascal; Metz, Alexandra; Prudent, Renaud; Deshiere, Alexandre; Dideberg, Otto; Filhol, Odile; Cochet, Claude

    2007-01-01

    X-ray crystallography studies, as well as live-cell fluorescent imaging, have recently challenged the traditional view of protein kinase CK2. Unbalanced expression of catalytic and regulatory CK2 subunits has been observed in a variety of tissues and tumours. Thus the potential intersubunit flexibility suggested by these studies raises the likely prospect that the CK2 holoenzyme complex is subject to disassembly and reassembly. In the present paper, we show evidence for the reversible multimeric organization of the CK2 holoenzyme complex in vitro. We used a combination of site-directed mutagenesis, binding experiments and functional assays to show that, both in vitro and in vivo, only a small set of primary hydrophobic residues of CK2β which contacts at the centre of the CK2α/CK2β interface dominates affinity. The results indicate that a double mutation in CK2β of amino acids Tyr188 and Phe190, which are complementary and fill up a hydrophobic pocket of CK2α, is the most disruptive to CK2α binding both in vitro and in living cells. Further characterization of hotspots in a cluster of hydrophobic amino acids centred around Tyr188–Phe190 led us to the structure-based design of small-peptide inhibitors. One conformationally constrained 11-mer peptide (Pc) represents a unique CK2β-based small molecule that was particularly efficient (i) to antagonize the interaction between the CK2 subunits, (ii) to inhibit the assembly of the CK2 holoenzyme complex, and (iii) to strongly affect its substrate preference. PMID:17714077

  16. Diversifying Science: Underrepresented Student Experiences in Structured Research Programs

    PubMed Central

    Cabrera, Nolan L.; Lin, Monica H.; Arellano, Lucy; Espinosa, Lorelle L.

    2013-01-01

    Targeting four institutions with structured science research programs for undergraduates, this study focuses on how underrepresented students experience science. Several key themes emerged from focus group discussions: learning to become research scientists, experiences with the culture of science, and views on racial and social stigma. Participants spoke of essential factors for becoming a scientist, but their experiences also raised complex issues about the role of race and social stigma in scientific training. Students experienced the collaborative and empowering culture of science, exhibited strong science identities and high self-efficacy, while developing directed career goals as a result of “doing science” in these programs. PMID:23503690

  17. Structural Health Monitoring Sensor Development at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Wu, M. C.; Allison, S. G.; DeHaven, S. L.; Ghoshal, A.

    2002-01-01

    NASA is applying considerable effort on the development of sensor technology for structural health monitoring (SHM). This research is targeted toward increasing the safety and reliability of aerospace vehicles, while reducing operating and maintenance costs. Research programs are focused on applications to both aircraft and space vehicles. Sensor technologies under development span a wide range including fiber-optic sensing, active and passive acoustic sensors, electromagnetic sensors, wireless sensing systems, MEMS, and nanosensors. Because of their numerous advantages for aerospace applications, fiber-optic sensors are one of the leading candidates and are the major focus of this presentation. In addition, recent advances in active and passive acoustic sensing will also be discussed.

  18. Small-Molecule Inhibitors of GSK-3: Structural Insights and Their Application to Alzheimer's Disease Models

    PubMed Central

    Kramer, Thomas; Schmidt, Boris; Lo Monte, Fabio

    2012-01-01

    The world health organization (WHO) estimated that 18 million people are struck by Alzheimer's disease (AD). The USA, France, Germany, and other countries launched major programmes targeting the identification of risk factors, the improvement of caretaking, and fundamental research aiming to postpone the onset of AD. The glycogen synthase kinase 3 (GSK-3) is implicated in multiple cellular processes and has been linked to the pathogenesis of several diseases including diabetes mellitus, cancer, and AD. Inhibition of GSK-3 leads to neuroprotective effects, decreased β-amyloid production, and a reduction in tau hyperphosphorylation, which are all associated with AD. Various classes of small molecule GSK-3 inhibitors have been published in patents and original publications. Herein, we present a comprehensive summary of small molecules reported to interact with GSK-3. We illustrate the interactions of the inhibitors with the active site. Furthermore, we refer to the biological characterisation in terms of activity and selectivity for GSK-3, elucidate in vivo studies and pre-/clinical trials. PMID:22888461

  19. Whither Ribosome Structure and Dynamics Research? (A Perspective).

    PubMed

    Frank, Joachim

    2016-09-11

    As high-resolution cryogenic electron microscopy (cryo-EM) structures of ribosomes proliferate, at resolutions that allow atomic interactions to be visualized, this article attempts to give a perspective on the way research on ribosome structure and dynamics may be headed, and particularly the new opportunities we have gained through recent advances in cryo-EM. It is pointed out that single-molecule FRET and cryo-EM form natural complements in the characterization of ribosome dynamics and transitions among equilibrating states of in vitro translational systems.

  20. Structural and functional analysis of two small leucine-rich repeat proteoglycans, fibromodulin and chondroadherin.

    PubMed

    Paracuellos, Patricia; Kalamajski, Sebastian; Bonna, Arkadiusz; Bihan, Dominique; Farndale, Richard W; Hohenester, Erhard

    2017-02-17

    The small leucine-rich proteoglycans (SLRPs) are important regulators of extracellular matrix assembly and cell signalling. We have determined crystal structures at ~2.2Å resolution of human fibromodulin and chondroadherin, two collagen-binding SLRPs. Their overall fold is similar to that of the prototypical SLRP, decorin, but unlike decorin neither fibromodulin nor chondroadherin forms a stable dimer. A previously identified binding site for integrin α2β1 maps to an α-helix in the C-terminal cap region of chondroadherin. Interrogation of the Collagen Toolkits revealed a unique binding site for chondroadherin in collagen II, and no binding to collagen III. A triple-helical peptide containing the sequence GAOGPSGFQGLOGPOGPO (O is hydroxyproline) forms a stable complex with chondroadherin in solution. In fibrillar collagen I and II, this sequence is aligned with the collagen cross-linking site KGHR, suggesting a role for chondroadherin in cross-linking.

  1. Aggregates structure analysis of petroleum asphaltenes with small-angle neutron scattering.

    SciTech Connect

    Tanaka, R.; Hunt, J. E.; Winans, R. E.; Thiyagarajan, P.; Sato, S.; Takanohashi, T.; Idemitsu Kosan Co.; National Institute of Advanced Industrial Science and Technology

    2003-01-01

    The objective of this study is to examine changes in the structures of petroleum asphaltene aggregates in situ with small-angle neutron scattering (SANS). Asphaltenes were isolated from three different crude oils: Maya, Khafji, and Iranian Light. An aliquot of the 5 wt % asphaltene solution in deuterated Decalin, 1-methylnaphthalene, or quinoline was loaded in a special stainless steel cell for SANS measurements. SANS data measured at various temperatures from 25 to 350 {sup o}C showed various topological features different with asphaltene or solvent species. A fractal network was formed only with asphaltene of Maya in Decalin, and it remained even at 350 {sup o}C. In all of the solvents, asphaltenes aggregate in the form of a prolate ellipsoid with a high aspect ratio at 25 {sup o}C and got smaller with increasing temperature. That became a compact sphere with the size of around 25 {angstrom} in radius at 350 {sup o}C.

  2. Observations of small-scale latitudinal structure in energetic electron precipitation

    NASA Astrophysics Data System (ADS)

    Blake, J. B.; O'Brien, T. P.

    2016-04-01

    We describe first-light observations from the AC6 mission, a pair of CubeSats that are in polar orbit and whose in-track separations range up to several hundred kilometers and whose separations are controlled by differential drag. We present temporal dose rate profiles from electrons greater than 35 keV that are very similar at the two vehicles, but offset in time by the GPS-derived in-track separation. We interpret these structures as spatial and propose that they are the result of multiple microbursts that have experienced bounce phase mixing and differential drift over a small fraction of a drift orbit before reaching the spacecraft.

  3. Crystal structure of small protein crambin at 0.48 Å resolution

    PubMed Central

    Schmidt, Andrea; Teeter, Martha; Weckert, Edgar; Lamzin, Victor S.

    2011-01-01

    With the development of highly brilliant and extremely intense synchrotron X-­ray sources, extreme high-resolution limits for biological samples are now becoming attainable. Here, a study is presented that sets the record in crystallographic resolution for a biological macromolecule. The structure of the small protein crambin was determined to 0.48 Å resolution on the PETRA II ring before its conversion to a dedicated synchrotron-radiation source. The results reveal a wealth of details in electron density and demonstrate the possibilities that are potentially offered by a high-energy source. The question now arises as to what the true limits are in terms of what can be seen at such high resolution. From what can be extrapolated from the results using crystals of crambin, this limit would be at approximately 0.40 Å, which approaches that for smaller compounds. PMID:21505232

  4. Crystal structure of small protein crambin at 0.48 Å resolution.

    PubMed

    Schmidt, Andrea; Teeter, Martha; Weckert, Edgar; Lamzin, Victor S

    2011-04-01

    With the development of highly brilliant and extremely intense synchrotron X-ray sources, extreme high-resolution limits for biological samples are now becoming attainable. Here, a study is presented that sets the record in crystallographic resolution for a biological macromolecule. The structure of the small protein crambin was determined to 0.48 Å resolution on the PETRA II ring before its conversion to a dedicated synchrotron-radiation source. The results reveal a wealth of details in electron density and demonstrate the possibilities that are potentially offered by a high-energy source. The question now arises as to what the true limits are in terms of what can be seen at such high resolution. From what can be extrapolated from the results using crystals of crambin, this limit would be at approximately 0.40 Å, which approaches that for smaller compounds.

  5. Detection of small-scale structures in the dissipation regime of solar-wind turbulence.

    PubMed

    Perri, S; Goldstein, M L; Dorelli, J C; Sahraoui, F

    2012-11-09

    Recent observations of the solar wind have pointed out the existence of a cascade of magnetic energy from the scale of the proton Larmor radius ρ(p) down to the electron Larmor radius ρ(e) scale. In this Letter we study the spatial properties of magnetic field fluctuations in the solar wind and find that at small scales the magnetic field does not resemble a sea of homogeneous fluctuations, but rather a two-dimensional plane containing thin current sheets and discontinuities with spatial sizes ranging from l >/~ ρ(p) down to ρ(e) and below. These isolated structures may be manifestations of intermittency that localize sites of turbulent dissipation. Studying the relationship between turbulent dissipation, reconnection, and intermittency is crucial for understanding the dynamics of laboratory and astrophysical plasmas.

  6. Theoretical study of structure and stability of small gadolinium carboxylate complexes in liquid scintillator solvents.

    PubMed

    Huang, Pin-Wen

    2014-09-01

    The structural properties of three small gadolinium carboxylate complexes in three liquid scintillator solvents (pseudocumene, linear alkylbenzene, and phenyl xylylethane) were theoretically investigated using density functional theory (B3LYP/LC-RECP) and polarizable continuum model (PCM). The average interaction energy between gadolinium atom and carboxylate ligand (E(int)) and the energy difference of the highest singly occupied molecular orbital and lowest unoccupied molecular orbital (Δ(SL)) were calculated to evaluate and compare the relative stability of these complexes in solvents. The calculation results show that the larger (with a longer alkyl chain) gadolinium carboxylate complex has greater stability than the smaller one, while these gadolinium carboxylates in linear alkylbenzene were found to have greater stability than those in the other two solvents.

  7. Morphological and structural characterization of PHBV/organoclay nanocomposites by small angle X-ray scattering.

    PubMed

    Carli, Larissa N; Bianchi, Otávio; Machado, Giovanna; Crespo, Janaina S; Mauler, Raquel S

    2013-03-01

    In this work, the morphological and structural behaviors of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) nanocomposites were investigated using small angle X-ray scattering (SAXS), wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). The nanocomposites with 1, 3 and 5 wt.% of organically modified montmorillonite Cloisite® 30B (OMMT) were prepared by melt processing in a twin screw extruder using two different processing conditions (low and high shear intensity). The lamellar long period of the polymer was lower for the nanocomposites, with high polydispersity values. However, the crystalline thickness increased with the clay content and was independent of the processing conditions. This behavior resulted in a high linear crystallinity of the nanocomposites with 3 and 5 wt.% OMMT. The disruption factor (β) was in agreement with the WAXD and TEM findings, indicating a good dispersion of the nanoparticles in the PHBV matrix with 3 wt.% of OMMT during the high shear intensity of melt processing.

  8. Structure and Expression of a Novel Compact Myelin Protein - Small VCP-Interacting Protein (SVIP)

    PubMed Central

    Wu, Jiawen; Peng, Dungeng; Voehler, Markus; Sanders, Charles R.; Li, Jun

    2013-01-01

    SVIP (small p97/VCP-interacting protein) was initially identified as one of many cofactors regulating the valosin containing protein (VCP), an AAA+ ATPase involved in endoplasmic-reticulum-associated protein degradation (ERAD). Our previous study showed that SVIP is expressed exclusively in the nervous system. In the present study, SVIP and VCP were seen to be co-localized in neuronal cell bodies. Interestingly, we also observed that SVIP co-localizes with myelin basic protein (MBP) in compact myelin, where VCP was absent. Furthermore, using nuclear magnetic resonance (NMR) and circular dichroism (CD) spectroscopic measurements, we determined that SVIP is an intrinsically disordered protein (IDP). However, upon binding to the surface of membranes containing a net negative charge, the helical content of SVIP increases dramatically. These findings provide structural insight into interactions between SVIP and myelin membranes. PMID:24055875

  9. The correspondence between small-scale coronal structures and the evolving solar magnetic field

    NASA Technical Reports Server (NTRS)

    Webb, D. F.; Moses, J. Daniel

    1989-01-01

    Solar coronal bright points, first identified in soft X-rays as X-ray Bright Points (XBPs), are compact, short lived and associated with small bipolar magnetic flux. Contradictory studies have suggested that XBPs are either a primary signature of the emerging flux spectrum of the quiet Sun, or that they are representative of the disappearance of pre-existing flux. Results are presented using coordinated data obtained during recent X-ray sounding rocket flights on 15 August and 11 December 1987 to determine the correspondence of XBPs with time-series, ground based observations of evolving bipolar magnetic structures, He-I dark points, and the network. The results are consistent with the view that coronal bright points are more likely to be associated with the annihilation of pre-existing flux than with emerging flux.

  10. Structure-Guided Reprogramming of a Hydroxylase To Halogenate Its Small Molecule Substrate.

    PubMed

    Mitchell, Andrew J; Dunham, Noah P; Bergman, Jonathan A; Wang, Bo; Zhu, Qin; Chang, Wei-Chen; Liu, Xinyu; Boal, Amie K

    2017-01-24

    Enzymatic installation of chlorine/bromine into unactivated carbon centers provides a versatile, selective, and environmentally friendly alternative to chemical halogenation. Iron(II) and 2-(oxo)-glutarate (Fe(II)/2OG)-dependent halogenases are powerful biocatalysts that are capable of cleaving aliphatic C-H bonds to introduce useful functional groups, including halogens. Using the structure of the Fe/2OG halogenase, WelO5, in complex with its small molecule substrate, we identified a similar N-acyl amino acid hydroxylase, SadA, and reprogrammed it to halogenate its substrate, thereby generating a new chiral haloalkyl center. The work highlights the potential of Fe(II)/2OG enzymes as platforms for development of novel stereospecific catalysts for late-stage C-H functionalization.

  11. A mathematical model of the structure and evolution of small scale discrete auroral arcs

    NASA Technical Reports Server (NTRS)

    Seyler, C. E.

    1990-01-01

    A three dimensional fluid model which includes the dispersive effect of electron inertia is used to study the nonlinear macroscopic plasma dynamics of small scale discrete auroral arcs within the auroral acceleration zone and ionosphere. The motion of the Alfven wave source relative to the magnetospheric and ionospheric plasma forms an oblique Alfven wave which is reflected from the topside ionosphere by the negative density gradient. The superposition of the incident and reflected wave can be described by a steady state analytical solution of the model equations with the appropriate boundary conditions. This two dimensional discrete auroral arc equilibrium provides a simple explanation of auroral acceleration associated with the parallel electric field. Three dimensional fully nonlinear numerical simulations indicate that the equilibrium arc configuration evolves three dimensionally through collisionless tearing and reconnection of the current layer. The interaction of the perturbed flow and the transverse magnetic field produces complex transverse structure that may be the origin of the folds and curls observed to be associated with small scale discrete arcs.

  12. Structural and Functional Small Fiber Abnormalities in the Neuropathic Postural Tachycardia Syndrome

    PubMed Central

    Gibbons, Christopher H.; Bonyhay, Istvan; Benson, Adam; Wang, Ningshan; Freeman, Roy

    2013-01-01

    Objective To define the neuropathology, clinical phenotype, autonomic physiology and differentiating features in individuals with neuropathic and non-neuropathic postural tachycardia syndrome (POTS). Methods Twenty-four subjects with POTS and 10 healthy control subjects had skin biopsy analysis of intra-epidermal nerve fiber density (IENFD), quantitative sensory testing (QST) and autonomic testing. Subjects completed quality of life, fatigue and disability questionnaires. Subjects were divided into neuropathic and non-neuropathic POTS, defined by abnormal IENFD and abnormal small fiber and sudomotor function. Results Nine of 24 subjects had neuropathic POTS and had significantly lower resting and tilted heart rates; reduced parasympathetic function; and lower phase 4 valsalva maneuver overshoot compared with those with non-neuropathic POTS (P<0.05). Neuropathic POTS subjects also had less anxiety and depression and greater overall self-perceived health-related quality of life scores than non-neuropathic POTS subjects. A sub-group of POTS patients (cholinergic POTS) had abnormal proximal sudomotor function and symptoms that suggest gastrointestinal and genitourinary parasympathetic nervous system dysfunction. Conclusions and Relevance POTS subtypes may be distinguished using small fiber and autonomic structural and functional criteria. Patients with non-neuropathic POTS have greater anxiety, greater depression and lower health-related quality of life scores compared to those with neuropathic POTS. These findings suggest different pathophysiological processes underlie the postural tachycardia in neuropathic and non-neuropathic POTS patients. The findings have implications for the therapeutic interventions to treat this disorder. PMID:24386408

  13. Structural analysis of Fe–Mn–O nanoparticles in glass ceramics by small angle scattering

    SciTech Connect

    Raghuwanshi, Vikram Singh; Harizanova, Ruzha; Tatchev, Dragomir; Hoell, Armin; Rüssel, Christian

    2015-02-15

    Magnetic nanocrystals containing Fe and Mn were obtained by annealing of silicate glasses with the composition 13.6Na{sub 2}O–62.9SiO{sub 2}–8.5MnO–15.0Fe{sub 2}O{sub 3−x} (mol%) at 580 °C for different periods of time. Here, we present Small Angle Neutron Scattering using Polarized neutrons (SANSPOL) and Anomalous Small Angle X-ray Scattering (ASAXS) investigation on these glass ceramic samples. Analysis of scattering data from both methods reveals the formation of spherical core–shell type of nanoparticles with mean sizes between 10 nm and 100 nm. ASAXS investigation shows the particles have higher concentration of iron atoms and the shell like region surrounding the particles is enriched in SiO{sub 2}. SANSPOL investigation shows the particles are found to be magnetic and are surrounded by a non-magnetic shell-like region. - Graphical abstract: Magnetic spherical core–shell nanoparticles in glass ceramics: SANSPOL and ASAXS investigations. - Highlights: • Formation and growth mechanisms of magnetic nanoparticles in silicate glass. • SANSPOL and ASAXS methods employed to evaluate quantitative information. • Analyses showed formation of nanoparticles with spherical core–shell structures. • Core of the particle is magnetic and surrounded by weak magnetic shell like region.

  14. Theoretical study of successive hydrogenations of small platinum clusters: structure and energetics

    SciTech Connect

    Minot, C.; Bigot, B.; Hariti, A.

    1986-01-22

    The successive hydrogenations, up to saturation, of the most stable small platinum clusters Pt/sub n/ (n = 2-13) are studied by the extended Huckel method with (EHT-SO) and without (EHT) spin-orbit coupling. For each hydrogenation step, a large number of possible structures has been calculated in order to determine the stereochemistry of the best stepwise hydrogenated compounds. The results indicate that the energies of the first successive steps of dihydrogen adsorptions on the small clusters decrease stepwise with the hydrogenation rate, except for a few steps which are discussed. In these conditions, if the hydrogenation reactions are either under thermodynamic control or under kinetic control with activation energies related to the reaction enthalpies, all the clusters of a given size will absorb a first H/sub 2/ molecule before one of them can adsorb a second molecule. Another remarkable point is that the energy of first absorption varies with the cluster size. It shows a peak for Pt/sub 3/ and Pt/sub 4/ that makes the Pt/sub 3/ and Pt/sub 4/ species the most likely clusters to be hydrogenated first in a collection of clusters of different size. 19 references, 9 figures, 5 tables.

  15. Electronic structure transformation in small bare Au clusters as seen by x-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Andersson, T.; Zhang, C.; Björneholm, O.; Mikkelä, M.-H.; Jänkälä, K.; Anin, D.; Urpelainen, S.; Huttula, M.; Tchaplyguine, M.

    2017-01-01

    Free bare gold clusters in the size range from few tens to few hundred atoms (≤1 nm dimensions) have been produced in a beam, and the size-dependent development of their full valence band including the 5d and 6s parts has been mapped ‘on the fly’ by synchrotron-based photoelectron spectroscopy. The Au 4f core level has been also probed, and the cluster-specific Au 4f ionization energies have been used to estimate the cluster size. The recorded in the present work valence spectra of the small clusters are compared with the spectra of the large clusters ( N ∼ 103) created by us using a magnetron-based gas aggregation source. The comparison shows a substantially narrower 5d valence band and the decrease in its splitting for gold clusters in the size range of few hundred atoms and below. Our DFT calculations involving the pseudopotential method show that the 5d band width of the ground state increases with the cluster size and by the size N = 20 becomes comparable with the experimental width of the valence photoelectron spectrum. Similar to the earlier observations on supported clusters we interpret our experimental and theoretical results as due to the undercoordination of a large fraction of atoms in the clusters with N ∼ 102 and below. The consequences of such electronic structure of small gold clusters are discussed in connection with their specific physical and chemical properties related to nanoplasmonics and nanocatalysis.

  16. Structural characterization and gas reactions of small metal particles by high-resolution TEM and TED

    NASA Technical Reports Server (NTRS)

    Heinemann, K.

    1985-01-01

    The interaction of 100 and 200 keV electron beams with amorphous alumina, titania, and aluminum nitride substrates and nanometer-size palladium particulate deposits was investigated for the two extreme cases of (1) large-area electron-beam flash-heating and (2) small-area high-intensity electron-beam irradiation. The former simulates a short-term heating effect with minimum electron irradiation exposure, the latter simulates high-dosage irradiation with minimum heating effect. All alumina and titania samples responded to the flash-heating treatment with significant recrystallization. However, the size, crystal structure, shape, and orientation of the grains depended on the type and thickness of the films and the thickness of the Pd deposit. High-dosage electron irradiation also readily crystallized the alumina substrate films but did not affect the titania films. The alumina recrystallization products were usually either all in the alpha phase, or they were a mixture of small grains in a number of low-temperature phases including gamma, delta, kappa, beta, theta-alumina. Palladium deposits reacted heavily with the alumina substrates during either treatment, but they were very little effected when supported on titania. Both treatments had the same, less prominent localized crystallization effect on aluminum nitride films.

  17. Research on large structure assembly technology: Research on deployable assembly structure

    NASA Astrophysics Data System (ADS)

    Morino, Yoshiki; Shibuta, Shigeto

    1992-08-01

    An overview of the simulation analyses of element mechanisms for deployable assembly structures is presented. System mechanism analyses were conducted using a mathematical model constructed for one unit cell of the deployable trusses. Element mechanism analyses were conducted using mathematical models constructed for each of the critical elements of deployable trusses, such as telescopically deployable section, joint section, deployment and folding driving mechanism, and so forth. Review on the function, characteristics, and the scope of mechanism analysis software to study on ground and on orbit deployment technologies were conducted. Preliminary review was conducted on test equipment and techniques to effectively facilitate the deployment function verification. Conceptual design of the docking mechanism for the Engineering Test Satellite-7 (ETS-7) to acquire the Rendezvous and Docking (RVD) and robotic technologies was conducted. Some examples of the simulation are shown.

  18. Changes of creatine kinase structure upon ligand binding as seen by small-angle scattering

    NASA Astrophysics Data System (ADS)

    Forstner, Michael; Kriechbaum, Manfred; Laggner, Peter; Wallimann, Theo

    1996-09-01

    Small-angle X-ray and neutron scattering have been used to investigate structural changes upon binding of individual substrates or a transition state analogue complex (TSAC), consisting of Mg-ADP, creatine and KNO 3 to creatine kinase isoenzymes (dimeric M-CK and octameric Mi-CK) and monomeric arginine kinase (AK). Considerable changes in the shape and the size of the molecules occurred upon binding of Mg-ATP and TSAC, whereas creatine alone had only a small effect. In Mi-CK, the radius of gyration was reduced from 55.6 Å (free enzyme) to 48.9 Å (enzyme + Mg-ATP) and to 48.2 Å (enzyme + TSAC). The experiments performed with M-CK showed similar changes from 28.0 Å (free enzyme) to 25.6 Å (enzyme + Mg-ATP) and to 25.5 Å (enzyme + TSAC). Creatine alone did not lead to significant changes in the radii of gyration, nor did free ATP or ADP. AK showed the same behaviour: a change of the radius of gyration from 21.5 Å (free enzyme) to 19.7 Å (enzyme + MG-ATP), whereas with arginine alone only a minor change could be observed. The primary change in structure as seen with monomeric AK seems to be a magnesium-nucleotide induced domain movement relative to each other, whereas the effect of substrate may be of local order only. In creatine kinase, however, further movements must be involved in the large conformational change.

  19. Substrate specificity determinants of the methanogen homoaconitase enzyme: structure and function of the small subunit.

    PubMed

    Jeyakanthan, Jeyaraman; Drevland, Randy M; Gayathri, Dasara Raju; Velmurugan, Devadasan; Shinkai, Akeo; Kuramitsu, Seiki; Yokoyama, Shigeyuki; Graham, David E

    2010-03-30

    The aconitase family of hydro-lyase enzymes includes three classes of proteins that catalyze the isomerization of alpha-hydroxy acids to beta-hydroxy acids. Besides aconitase, isopropylmalate isomerase (IPMI) proteins specifically catalyze the isomerization of alpha,beta-dicarboxylates with hydrophobic gamma-chain groups, and homoaconitase (HACN) proteins catalyze the isomerization of tricarboxylates with variable chain length gamma-carboxylate groups. These enzymes' stereospecific hydro-lyase activities make them attractive catalysts to produce diastereomers from unsaturated precursors. However, sequence similarity and convergent evolution among these proteins lead to widespread misannotation and uncertainty about gene function. To find the substrate specificity determinants of homologous IPMI and HACN proteins from Methanocaldococcus jannaschii, the small-subunit HACN protein (MJ1271) was crystallized for X-ray diffraction. The structural model showed characteristic residues in a flexible loop region between alpha2 and alpha3 that distinguish HACN from IPMI and aconitase proteins. Site-directed mutagenesis of MJ1271 produced loop-region variant proteins that were reconstituted with wild-type MJ1003 large-subunit protein. The heteromers formed promiscuous hydro-lyases with reduced activity but broader substrate specificity. Both R26K and R26V variants formed relatively efficient IPMI enzymes, while the T27A variant had uniformly lower specificity constants for both IPMI and HACN substrates. The R26V T27Y variant resembles the MJ1277 IPMI small subunit in its flexible loop sequence but demonstrated the broad substrate specificity of the R26V variant. These mutations may reverse the evolution of HACN activity from an ancestral IPMI gene, demonstrating the evolutionary potential for promiscuity in hydro-lyase enzymes. Understanding these specificity determinants enables the functional reannotation of paralogous HACN and IPMI genes in numerous genome sequences. These

  20. Structure of small-scale magnetic fields in the kinematic dynamo theory.

    PubMed

    Schekochihin, Alexander; Cowley, Steven; Maron, Jason; Malyshkin, Leonid

    2002-01-01

    A weak fluctuating magnetic field embedded into a a turbulent conducting medium grows exponentially while its characteristic scale decays. In the interstellar medium and protogalactic plasmas, the magnetic Prandtl number is very large, so a broad spectrum of growing magnetic fluctuations is excited at small (subviscous) scales. The condition for the onset of nonlinear back reaction depends on the structure of the field lines. We study the statistical correlations that are set up in the field pattern and show that the magnetic-field lines possess a folding structure, where most of the scale decrease is due to the field variation across itself (rapid transverse direction reversals), while the scale of the field variation along itself stays approximately constant. Specifically, we find that, though both the magnetic energy and the mean-square curvature of the field lines grow exponentially, the field strength and the field-line curvature are anticorrelated, i.e., the curved field is relatively weak, while the growing field is relatively flat. The detailed analysis of the statistics of the curvature shows that it possesses a stationary limiting distribution with the bulk located at the values of curvature comparable to the characteristic wave number of the velocity field and a power tail extending to large values of curvature where it is eventually cut off by the resistive regularization. The regions of large curvature, therefore, occupy only a small fraction of the total volume of the system. Our theoretical results are corroborated by direct numerical simulations. The implication of the folding effect is that the advent of the Lorentz back reaction occurs when the magnetic energy approaches that of the smallest turbulent eddies. Our results also directly apply to the problem of statistical geometry of the material lines in a random flow.