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Sample records for study bases study

  1. Data base management study

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Data base management techniques and applicable equipment are described. Recommendations which will assist potential NASA data users in selecting and using appropriate data base management tools and techniques are presented. Classes of currently available data processing equipment ranging from basic terminals to large minicomputer systems were surveyed as they apply to the needs of potential SEASAT data users. Cost and capabilities projections for this equipment through 1985 were presented. A test of a typical data base management system was described, as well as the results of this test and recommendations to assist potential users in determining when such a system is appropriate for their needs. The representative system tested was UNIVAC's DMS 1100.

  2. Brain-Science Based Cohort Studies

    ERIC Educational Resources Information Center

    Koizumi, Hideaki

    2011-01-01

    This article describes a number of human cohort studies based on the concept of brain-science and education. These studies assess the potential effects of new technologies on babies, children and adolescents, and test hypotheses drawn from animal and genetic case studies to see if they apply to people. A flood of information, virtual media,…

  3. Systems engineering studies of lunar base construction

    NASA Technical Reports Server (NTRS)

    Morgenthaler, George W.

    1991-01-01

    Many ingenious concepts have been proposed for lunar base construction, but few systematic studies exist which relate time-consistent lunar base construction technologies and the choice of lunar base approach with the long-term SEI objectives - i.e., lunar indigenous base construction and Mars Exploration equipment development. To fill this gap, CSC has taken a two-pronged approach. First, the Center undertook basic geotechnical investigations of lunar soil, fabrication of a scale prototype of a lunar construction crane, a multi-robot construction team laboratory experiment, and a preliminary design of lunar base structures. Second, during Jun. and Jul. 1991 two lunar base construction systems engineering studies were accomplished - a 'near term lunar base' study, and a 'far-term lunar base' study. The goals of these studies were to define the major lunar base construction research problems in consistent technology/construction frameworks, and to define design requirements for construction equipment such as a lunar crane and a regolith mover. The 'near-term lunar base' study examined three different construction concepts for a lunar base comprised of pre-fabricated, pre-tested, Space Station Freedom-type modules, which would be covered with regolith shielding. Concept A used a lunar crane for unloading and transportation; concept B, a winch and cart; and concept C, a walker to move the modules from the landing site to the base site and assemble them. To evaluate the merits of each approach, calculations were made of mass efficiency measure, source mass, reliability, far-term base mass, Mars base mass, and base assembly time. The model thus established was also used to define the requirements for crane speed and regolith mover m(sup 3)/sec rates. A major problem addressed is how to 'mine' the regolith and stack it over the habitats as shielding. To identify when the cost of using indigenous lunar materials to construct the base exceeds the cost of development and

  4. Competency Based Education: A Sociological Study.

    ERIC Educational Resources Information Center

    Graham, Thomas E.

    This study focuses on the Competency Based Education (CBE) movement in a small Ohio school district, asking whether it represents radical change or reenforces status-quo social stratification. CBE was a product of the recent public demand for more educational accountability. It is a radical shift from traditional U.S. education insofar as it…

  5. The Conceptual Bases of Study Strategy Inventories

    ERIC Educational Resources Information Center

    Entwistle, Noel; McCune, Velda

    2004-01-01

    This article describes the historical origins and development of a series of well-known study strategy inventories and seeks to identify their conceptual bases. The theories and evidence influencing the development of 6 contrasting instruments are considered before examining empirical evidence of similarities and differences between the…

  6. Becoming occupation-based: a case study.

    PubMed

    Skubik-Peplaski, Camille; Howell, Dana; Harrison, Anne

    2014-10-01

    This descriptive case study illustrates the experiences of a 55-year-old male with a chronic disability resulting from a stroke, living in the community and a clinician's trial using occupation-based interventions predominately in a rehabilitation setting. The participant engaged in occupation-based interventions three times a week for 5 weeks guided by the Canadian Occupational Performance Measure (COPM). Data were collected through semi-structured interviews during the intervention sessions and journal entries made by the therapist. Results suggested occupation-based interventions facilitated a transformation for both the client and the therapist by enhancing the participant's occupational performance and the ability to resume previous roles. The therapist's belief in the power and value of occupation-based practice was reinforced and validated, particularly in the rehabilitation of an individual with chronic stroke. PMID:24867352

  7. Studies of anisotropy of iron based superconductors

    SciTech Connect

    Murphy, Jason A.

    2013-01-01

    To study the electronic anisotropy in iron based superconductors, the temperature dependent London penetration depth, Δλ(T), have been measured in several compounds, along with the angular dependent upper critical field, Hc2(T). Study was undertaken on single crystals of Ba(Fe1-xCox)2As2 with x=0.108 and x=0.127, in the overdoped range of the doping phase diagram, characterized by notable modulation of the superconducting gap. Heavy ion irradiation with matching field doses of 6 T and 6.5 T respectively, were used to create columnar defects and to study their effect on the temperature Δλ(T). The variation of the low-temperature penetration depth in both pristine and irradiated samples was fitted with a power-law function Δλ(T) = ATn. Irradiation increases the magnitude of the pre-factor A and decreases the exponent n, similar to the effect on the optimally doped samples. This finding supports the universal s ± scenario for the whole doping range.

  8. Dielectronic recombination studies based on EBIT

    SciTech Connect

    Xiao Jun; Han Chuan; Yao Ke; Shen Yang; Yang Yang; Wei Baoren; Fu Yunqing; Lu Di; Hutton, Roger; Zou Yaming

    2013-04-19

    Dielectronic recombination (DR) process plays an important role in high temperature plasmas, where DR can affect charge balance and level populations significantly, and can cause radiative energy loss. Resolvable DR sourced satellite lines are often used for plasma temperature diagnostics, while the un-resolvable ones disturb determining spectral line shape, line intensity, and line position. Data of DR resonant strength is vital for accurate modeling of high temperature plasmas. DR studies are also important for testing atomic structure and atomic collision theories, since they carry information on quantum electrodynamics, relativistic effects, electron correlations and so on. Electron beam ion trap (EBIT) is an accelerator type device, which is capable of acting as both ion sources and light sources. EBIT can produce a special sort of plasma, in which electron energy is tunable and has a very narrow distribution. This made it possible for disentanglement studies on electron ion collision processes in plasmas. In this paper, experimental studies of DR processes based on electron beam ion traps (EBIT) will be discussed.

  9. Design Study: Rocket Based MHD Generator

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This report addresses the technical feasibility and design of a rocket based MHD generator using a sub-scale LOx/RP rocket motor. The design study was constrained by assuming the generator must function within the performance and structural limits of an existing magnet and by assuming realistic limits on (1) the axial electric field, (2) the Hall parameter, (3) current density, and (4) heat flux (given the criteria of heat sink operation). The major results of the work are summarized as follows: (1) A Faraday type of generator with rectangular cross section is designed to operate with a combustor pressure of 300 psi. Based on a magnetic field strength of 1.5 Tesla, the electrical power output from this generator is estimated to be 54.2 KW with potassium seed (weight fraction 3.74%) and 92 KW with cesium seed (weight fraction 9.66%). The former corresponds to a enthalpy extraction ratio of 2.36% while that for the latter is 4.16%; (2) A conceptual design of the Faraday MHD channel is proposed, based on a maximum operating time of 10 to 15 seconds. This concept utilizes a phenolic back wall for inserting the electrodes and inter-electrode insulators. Copper electrode and aluminum oxide insulator are suggested for this channel; and (3) A testing configuration for the sub-scale rocket based MHD system is proposed. An estimate of performance of an ideal rocket based MHD accelerator is performed. With a current density constraint of 5 Amps/cm(exp 2) and a conductivity of 30 Siemens/m, the push power density can be 250, 431, and 750 MW/m(sup 3) when the induced voltage uB have values of 5, 10, and 15 KV/m, respectively.

  10. Structural studies of Hollandite based radioactive wasteformd

    NASA Astrophysics Data System (ADS)

    Whittle, K. R.; Maddrell, E. R.; Ashbrook, S. E.; Sartbaeva, A.; Attfield, J. P.; Dove, M. T.; Farnan, I.; Redfern, S. A. T.

    2003-04-01

    Materials based on the hollandite-type structure, Ba1.2-xCs_x(Al,Mg,Ti)_8O16 (x=0,0.1,0.25) have been studied as a basis for 135Cs and 137Cs active waste immobilisation. Powders have been prepared using a modified 2-stage isopropoxide-gel route. The samples have been consolidated using both Hot Isostatic Pressing (HIP) and Cold Uniaxial Pressing prior to sintering.. The structures of these materials have been determined using X-ray diffraction techniques, and Magic-Angle Spinning Nuclear Magnetic Resonance (MAS-NMR). Dielectric spectroscopy has been measured for these systems to determine mobility of the Cs^+ ion in the structure. The structural data is compared for both pressing techniques and by direct comparison with the pseudo-amorphous precursor. The dielectric spectroscopy data has been collected for the pressed and fired samples.

  11. The Manhattan community based particulate study

    SciTech Connect

    Tropp, R.; Mustafa, M.; Werner, R.

    1998-12-31

    This study examines PM10 concentrations in two communities in northern Manhattan over a period of approximately 80 days during July through September 1996. The study was conducted to address community concerns that particulate levels in the neighborhoods caused by diesel bus and truck traffic might be higher than in other parts of Manhattan and cause the higher levels of asthma observed in the two communities. Community representatives were active participants throughout the study, including selecting monitoring sites. Sampling was conducted in two phases with saturation samplers, first, at eight street level locations in the Harlem community and then at seven locations in the Washington Heights community plus one continuing site in Harlem. During both phases, the samplers were located at sites in midtown and downtown Manhattan at which New York State operated dichotomous samplers. In addition, saturation samplers were used at a subset of sites to collect PM2.5 samples and, during Phase 2, samples for analysis of elemental and organic carbon. Community site samples were collected every day and reference site samples about once every three days. Temporal variability for PM10 was greater than spatial variability. Community sites generally had lower PM10 and PM2.5 concentrations than either of the two reference sites, averaging two-thirds to three-fourths the levels at the reference sites. Only the two reference samplers recorded PM10 concentrations that would indicate a likelihood of exceeding the annual PM10 National Ambient Air Quality Standards (NAAQS). Based on the PM2.5/PM10 ratio measured at reference and community sites, estimates of PM2.5 from PM10 measurements indicated that most community sites might not meet the annual PM2.5 NAAQS and a few sites might fail to meet the 24-hour NAAQS.

  12. Ground Based Studies of the Outer Planets

    NASA Technical Reports Server (NTRS)

    Trafton, Laurence M.

    2005-01-01

    This report covers progress to date under this grant on our continuing program to conduct ground based studies of the outer solar system planets and satellites, with emphasis on spectroscopy and atmospheric phenomena. The research continues under our new PAST grant, NNG04G131G beginning 5/1/2004. The original period of performance of the subject grant was 3/1/2001 to 2/28/2004, but was extended one year at no cost. Although there is some overlap in the scientific projects conducted during the extended year with those of the new grant, this report is confined to the portion of the work funded under NAG5-10435. The primary goals for this grant period were a comparative study of outer planet thermospheres/ionospheres near solar maximum, extended to the mid-IR, and the investigation of molecular dimers in outer solar system atmospheres. This project supports NASA's planned space missions, Jupiter Polar Orbiter, outer Planet Microprobes, and the recent Cassini flyby of Jupiter. It also supports the OSS strategic plan themes, The Exploration of the Solar System and The Sun-Earth Connection/ Understanding comparative planetary space environments.

  13. Feasibility Studies on Si-Based Biosensors

    PubMed Central

    Libertino, Sebania; Aiello, Venera; Scandurra, Antonino; Renis, Marcella; Sinatra, Fulvia; Lombardo, Salvatore

    2009-01-01

    The aim of this paper is to summarize the efforts carried out so far in the fabrication of Si-based biosensors by a team of researchers in Catania, Italy. This work was born as a collaboration between the Catania section of the Microelectronic and Microsystem Institute (IMM) of the CNR, the Surfaces and Interfaces laboratory (SUPERLAB) of the Consorzio Catania Ricerche and two departments at the University of Catania: the Biomedical Science and the Biological Chemistry and Molecular Biology Departments. The first goal of our study was the definition and optimization of an immobilization protocol capable of bonding the biological sensing element on a Si-based surface via covalent chemical bonds. We chose SiO2 as the anchoring surface due to its biocompatibility and extensive presence in microelectronic devices. The immobilization protocol was tested and optimized, introducing a new step, oxide activation, using techniques compatible with microelectronic processing. The importance of the added step is described by the experimental results. We also tested different biological molecule concentrations in the immobilization solutions and the effects on the immobilized layer. Finally a MOS-like structure was designed and fabricated to test an electrical transduction mechanism. The results obtained so far and the possible evolution of the research field are described in this review paper. PMID:22412322

  14. Laminar Diffusion Flame Studies (Ground- and Space-Based Studies)

    NASA Technical Reports Server (NTRS)

    Dai, Z.; El-Leathy, A. M.; Lin, K.-C.; Sunderland, P. B.; Xu, F.; Faeth, G. M.; Urban, D. L. (Technical Monitor); Yuan, Z.-G. (Technical Monitor)

    2000-01-01

    Laminar diffusion flames are of interest because they provide model flame systems that are far more tractable for analysis and experiments than more practical turbulent diffusion flames. Certainly, understanding flame processes within laminar diffusion flames must precede understanding these processes in more complex turbulent diffusion flames. In addition, many properties of laminar diffusion flames are directly relevant to turbulent diffusion flames using laminar flamelet concepts. Laminar jet diffusion flame shapes (luminous flame boundaries) have been of particular interest since the classical study of Burke and Schumann because they are a simple nonintrusive measurement that is convenient for evaluating flame structure predictions. Thus, consideration of laminar flame shapes is undertaken in the following, emphasizing conditions where effects of gravity are small, due to the importance of such conditions to practical applications. Another class of interesting properties of laminar diffusion flames are their laminar soot and smoke point properties (i.e., the flame length, fuel flow rate, characteristic residence time, etc., at the onset of soot appearance in the flame (the soot point) and the onset of soot emissions from the flame (the smoke point)). These are useful observable soot properties of nonpremixed flames because they provide a convenient means to rate several aspects of flame sooting properties: the relative propensity of various fuels to produce soot in flames; the relative effects of fuel structure, fuel dilution, flame temperature and ambient pressure on the soot appearance and emission properties of flames; the relative levels of continuum radiation from soot in flames; and effects of the intrusion of gravity (or buoyant motion) on emissions of soot from flames. An important motivation to define conditions for soot emissions is that observations of laminar jet diffusion flames in critical environments, e.g., space shuttle and space station

  15. Lunar Base Thermoelectric Power Station Study

    SciTech Connect

    Determan, William; Frye, Patrick; Mondt, Jack; Fleurial, Jean-Pierre; Johnson, Ken; Stapfer, Gerhard; Brooks, Michael; Heshmatpour, Ben

    2006-01-20

    Under NASA's Project Prometheus, the Nuclear Space Power Systems Program, the Jet Propulsion Laboratory, Pratt and Whitney Rocketdyne, and Teledyne Energy Systems have teamed with a number of universities, under the Segmented Thermoelectric Multicouple Converter (STMC) Task, to develop the next generation of advanced thermoelectric converters for space reactor power systems. Work on the STMC converter assembly has progressed to the point where the lower temperature stage of the segmented multicouple converter assembly is ready for laboratory testing, and promising candidates for the upper stage materials have been identified and their properties are being characterized. One aspect of the program involves mission application studies to help define the potential benefits from the use of these STMC technologies for designated NASA missions such as a lunar base power station where kilowatts of power would be required to maintain a permanent manned presence on the surface of the moon. A modular 50 kWe thermoelectric power station concept was developed to address a specific set of requirements developed for this particular mission concept. Previous lunar lander concepts had proposed the use of lunar regolith as in-situ radiation shielding material for a reactor power station with a one kilometer exclusion zone radius to minimize astronaut radiation dose rate levels. In the present concept, we will examine the benefits and requirements for a hermetically-sealed reactor thermoelectric power station module suspended within a man-made lunar surface cavity. The concept appears to maximize the shielding capabilities of the lunar regolith while minimizing its handling requirements. Both thermal and nuclear radiation levels from operation of the station, at its 100-m exclusion zone radius, were evaluated and found to be acceptable. Site preparation activities are reviewed as well as transport issues for this concept. The goal of the study was to review the entire life cycle of

  16. Lunar base thermoelectric power station study

    NASA Technical Reports Server (NTRS)

    Determan, William; Frye, Patrick; Mondt, Jack; Fleurial, Jean-Pierre; Johnson, Ken; Stapfer, G.; Brooks, Michael D.; Heshmatpour, Ben

    2006-01-01

    Under NASA's Project Prometheus, the Nuclear Systems Program, the Jet Propulsion Laboratory, Pratt & Whitney Rocketdyne, and Teledyne Energy Systems have teamed with a number of universities, under the Segmented Thermoelectric Multicouple Converter (STMC) program, to develop the next generation of advanced thermoelectric converters for space reactor power systems. Work on the STMC converter assembly has progressed to the point where the lower temperature stage of the segmented multicouple converter assembly is ready for laboratory testing and the upper stage materials have been identified and their properties are being characterized. One aspect of the program involves mission application studies to help define the potential benefits from the use of these STMC technologies for designated NASA missions such as the lunar base power station where kilowatts of power are required to maintain a permanent manned presence on the surface of the moon. A modular 50 kWe thermoelectric power station concept was developed to address a specific set of requirements developed for this mission. Previous lunar lander concepts had proposed the use of lunar regolith as in-situ radiation shielding material for a reactor power station with a one kilometer exclusion zone radius to minimize astronaut radiation dose rate levels. In the present concept, we will examine the benefits and requirements for a hermetically-sealed reactor thermoelectric power station module suspended within a man-made lunar surface cavity. The concept appears to maximize the shielding capabilities of the lunar regolith while minimizing its handling requirements. Both thermal and nuclear radiation levels from operation of the station, at its 100-m exclusion zone radius, were evaluated and found to be acceptable. Site preparation activities are reviewed and well as transport issues for this concept. The goal of the study was to review the entire life cycle of the unit to assess its technical problems and technology

  17. Studies of anisotropy of iron based superconductors

    SciTech Connect

    Murphy, Jason

    2013-01-01

    To study the electronic anisotropy in iron based superconductors, the temperature dependent London penetration depth, Δλ (T), have been measured in several compounds, along with the angular dependent upper critical field, Hc2(T). Study was undertaken on single crystals of Ba(Fe1-xCox)2As2 with x=0.108 and x=0.127, in the overdoped range of the doping phase diagram, characterized by notable modulation of the superconducting gap. Heavy ion irradiation with matching field doses of 6 T and 6.5 T respectively, were used to create columnar defects and to study their effect on the temperature Δλ (T). The variation of the low-temperature penetration depth in both pristine and irradiated samples was fitted with a power-law function Δλ (T) = ATn. Irradiation increases the magnitude of the pre-factor A and decreases the exponent n, similar to the effect on the optimally doped samples. This finding supports the universal s± scenario for the whole doping range. Knowing that the s± gap symmetry exists across the superconducting dome for the electron doped systems, we next looked at λ (T), in optimally - doped, SrFe2(As1-xPx)2, x =0.35. Both, as-grown (Tc ~ 25 K) and annealed (Tc ~ 35 K) single crystals of SrFe2(As1-xPx)2 were measured. Annealing decreases the absolute value of the London penetration depth from λ(0) = 300 ± 10 nm in as-grown samples to λ (0) = 275±10 nm. At low temperatures, λ (T) ~ T indicates a superconducting gap with line nodes. Analysis of the full-temperature range superfluid density is consistent with the line nodes, but differs from the simple single-gap d-wave. The observed behavior is very similar to that of BaFe2(As1-xPx)2, showing that isovalently substituted pnictides are inherently different from

  18. Study of wheat protein based materials

    NASA Astrophysics Data System (ADS)

    Ye, Peng

    Wheat gluten is a naturally occurring protein polymer. It is produced in abundance by the agricultural industry, is biodegradable and very inexpensive (less than $0.50/lb). It has unique viscoelastic properties, which makes it a promising alternative to synthetic plastics. The unplasticized wheat gluten is, however, brittle. Plasticizers such as glycerol are commonly used to give flexibility to the articles made of wheat gluten but with the penalty of greatly reduced stiffness. Former work showed that the brittleness of wheat gluten can also be improved by modifying it with a tri-thiol additive with no penalty of reduced stiffness. However, the cost of the customer designed tri-thiol additive was very high and it was unlikely to make a cost effective material from such an expensive additive. Here we designed a new, inexpensive thiol additive called SHPVA. It was synthesized from polyvinyl alcohol (PVA) through a simple esterification reaction. The mechanical data of the molded wheat gluten/SHPVA material indicated that wheat gluten was toughened by SHPVA. As a control, the wheat gluten/PVA material showed no improvement compared with wheat gluten itself. Several techniques have been used to characterize this novel protein/polymer blend. Differential scanning calorimetric (DSC) study showed two phases in both wheat gluten/PVA and wheat gluten/SHPVA material. However, scanning electron microscope (SEM) pictures indicated that PVA was macroscopically separated from wheat gluten, while wheat gluten/SHPVA had a homogeneous look. The phase image from the atomic force microscope (AFM) gave interesting contrast based on the difference in the mechanical properties of these two phases. The biodegradation behavior of these protein/polymer blends was examined in soil. SHPVA was not degraded in the time period of the experiment. Wheat gluten/SHPVA degraded slower than wheat gluten. We also developed some other interesting material systems based on wheat gluten, including the

  19. Viscosity studies of water based magnetite nanofluids

    NASA Astrophysics Data System (ADS)

    Anu, K.; Hemalatha, J.

    2016-05-01

    Magnetite nanofluids of various concentrations have been synthesized through co-precipitation method. The structural and topographical studies made with the X-Ray Diffractometer and Atomic Force Microscope are presented in this paper. The density and viscosity studies for the ferrofluids of various concentrations have been made at room temperature. The experimental viscosities are compared with theoretical values obtained from Einstein, Batchelor and Wang models. An attempt to modify the Rosensweig model is made and the modified Rosensweig equation is reported. In addition, new empirical correlation is also proposed for predicting viscosity of ferrofluid at various concentrations.

  20. Adrenocorticotrophic Hormone Levels in Ground Based Studies

    NASA Technical Reports Server (NTRS)

    Campbell, B. O.

    1972-01-01

    Baseline values of immunoreactive ACTH were established in the normal healthy adult. Normal levels of ACTH secretion were determined for both the male and the female in circulating plasma and serum. The data obtained in these studies are particularly significant in that the sampling was carefully controlled; only healthy employed individuals of both sexes were tested in a routine work situation that would not be considered conducive to stress. It has been found that alterations in the classically described circadian rhythm of ACTH secretion can occur when activities (such as work/rest cycles) are imposed on the individual studied. These changes can be demonstrated even when there is no appreciable change noted in the rhythm of hydrocortisone secretion.

  1. [Study on thermoanalysis-based calamina processing].

    PubMed

    Meng, Xiang-Long; Ma, Jun-Nan; Cui, Nan-Nan; Pin, Yu-Hang; Li, Kun; Zhang, Shuo-Sheng

    2013-12-01

    Thermogravimetry (TG), TG-MS, Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM)-energy dispersive spectrometer(EDS) were adopted to investigate the pyrolysis characteristics of calamina. According to the findings of the qualitative and quantitative studies on the changes in the content of relevant elements, the whole shape, the functional groups, and the volatile components of calamina before and after being pyrolyzed, the 200-360, 580-750 degrees C were two sensitive temperature ranges related to the changes in effective component during calamina processing. Thermal weight loss was observed for ZnCO3, Zn(OH)2 and ZnCO3-2Zn(OH)2-H2O under 200-360 degrees C and for CaCO3 under 580-750 degrees C. The results of studies on chemical reaction kinetics showed good linear relations. This experiment integrated relevant methods and theories of physical chemistry and science of traditional Chinese medicine processing, and interpretes calamina processing techniques and mechanism, in order to provide a good example for modem studies on other traditional Chinese medicine processing. PMID:24791535

  2. [Model based study of myocardial stimulation mechanisms].

    PubMed

    Weiss, I; Urbaszek, A; Schaldach, M

    1997-01-01

    The present study investigated the mechanisms of electrical stimulation of a myocardial fibre with the aim of developing improved minimally invasive stimulation methods. Using a dynamic myocyte model, the ionic currents crossing the voltage-dependent channels of the membrane are computed. To trigger an action potential, the membrane must first be depolarized to the threshold potential, when further depolarization continues spontaneously through the avalanche-like opening of the sodium channels. For the development of an action potential, not merely the amount of charge injected into the cell during the stimulus is of importance, but an above-threshold magnitude of the stimulation current is also required. The smallest energy required is achieved when the stimulus duration is chosen to be equal to the chronaxie. A second aspect of the study concerned the far-field stimulation of a muscle fibre, achieved by generating a potential gradient along the fibre. First, using a continuous fibre model, the fibre activating function is computed. In a more detailed study, the discrete segmental structure of the fibre determined by the gap junctions is taken into account, and the impact of these junctions on the activating function analysed. By optimizing the electrode configuration, an appropriate activating function results which guarantees successful stimulation when its maximum is above than threshold potential. The most important finding is that the myocardium can be stimulated by floating electrodes, thus opening up new possibilities for a less invasive electro-stimulation of the heart. PMID:9172726

  3. Study on aluminium-based single films.

    PubMed

    Vinod Kumar, G S; García-Moreno, F; Babcsán, N; Brothers, A H; Murty, B S; Banhart, J

    2007-12-28

    In the present paper the authors studied isolated metallic films made from the same material used for making metallic foams, and then characterised their properties. Metal films were made from a liquid aluminium alloy reinforced with ceramic particles of known concentration. Melts without such particles were also investigated. It is shown that stable films could not be made from Al-Si alloy having no particles, and just extremely thin and fragile films could be made from commercially-pure Al. In contrast, aluminium alloys containing particles such as SiC and TiB(2) allowed pulling thin, stable films, which did not rupture. Significant thinning of films was observed when the particle concentration in the melt decreased. By in situ X-ray monitoring of liquid films during pulling, film thickness and drainage effects within the liquid film could be studied. The morphology and microstructure of films was characterised after solidification. Our work shows that the question of how foams are stabilised can be studied using a simplified system such as a film, instead of having to deal with the multitude of different structural elements present in a foam. PMID:18060172

  4. Epidemiologic studies based on the Chernobyl accident

    SciTech Connect

    Beebe, G.

    1996-12-31

    There are great opportunities in the post-Chernobyl experience for significant epidemiologic research, perhaps even more in the area of disaster research than in the area of the human health effects of ionizing radiation. But the potential opportunity for learning the effects of radioiodine on the thyroid is very great and has aroused widespread national and international investigative interest. The opportunities for significant epidemiologic research are, however, severely limited currently by the worsening economic situation in Belarus and Ukraine, where the greatest exposure occurred, and by the lack of personnel trained in appropriate methods of study, the lack of modern equipment, the lack of supplies, the poor communication facilities, and the difficulties of accurate dose estimation. the disadvantages may or may not outweigh the obvious advantages of large numbers, the extensive direct thyroidal measurements made shortly after the accident in 1986, the magnitude of the releases of radioiodine, and the retention of the former Soviet system of universal medical care. Both the European Commission (EC) and the World Health Organization (WHO) have been working actively to strengthen the infrastructure of Russia, Belarus, and Ukraine. New scientific knowledge has yet to emerge from the extensive epidemiologic work but information of considerable public health significance has begun to accumulate. The bulk of the thyroid cancer has been shown to be valid by international pathology review; both EC and WHO representatives have declared the increase in thyroid cancer among children to have been caused in large part by Chernobyl. No increase in leukemia has been seen in the general population. The WHO pilot studies have shown no evidence of an increase in psychologic or neurologic complications among those exposed in utero. Ongoing epidemiologic work can be described by review of the inventory that the WHO has begun to maintain and publish. 20 refs., 7 tabs.

  5. Contrail study with ground-based cameras

    NASA Astrophysics Data System (ADS)

    Schumann, U.; Hempel, R.; Flentje, H.; Garhammer, M.; Graf, K.; Kox, S.; Lösslein, H.; Mayer, B.

    2013-08-01

    Photogrammetric methods and analysis results for contrails observed with wide-angle cameras are described. Four cameras of two different types (view angle < 90° or whole-sky imager) at the ground at various positions are used to track contrails and to derive their altitude, width, and horizontal speed. Camera models for both types are described to derive the observation angles for given image coordinates and their inverse. The models are calibrated with sightings of the Sun, the Moon and a few bright stars. The methods are applied and tested in a case study. Four persistent contrails crossing each other together with a short-lived one are observed with the cameras. Vertical and horizontal positions of the contrails are determined from the camera images to an accuracy of better than 200 m and horizontal speed to 0.2 m s-1. With this information, the aircraft causing the contrails are identified by comparison to traffic waypoint data. The observations are compared with synthetic camera pictures of contrails simulated with the contrail prediction model CoCiP, a Lagrangian model using air traffic movement data and numerical weather prediction (NWP) data as input. The results provide tests for the NWP and contrail models. The cameras show spreading and thickening contrails suggesting ice-supersaturation in the ambient air. The ice-supersaturated layer is found thicker and more humid in this case than predicted by the NWP model used. The simulated and observed contrail positions agree up to differences caused by uncertain wind data. The contrail widths, which depend on wake vortex spreading, ambient shear and turbulence, were partly wider than simulated.

  6. Contrail study with ground-based cameras

    NASA Astrophysics Data System (ADS)

    Schumann, U.; Hempel, R.; Flentje, H.; Garhammer, M.; Graf, K.; Kox, S.; Lösslein, H.; Mayer, B.

    2013-12-01

    Photogrammetric methods and analysis results for contrails observed with wide-angle cameras are described. Four cameras of two different types (view angle < 90° or whole-sky imager) at the ground at various positions are used to track contrails and to derive their altitude, width, and horizontal speed. Camera models for both types are described to derive the observation angles for given image coordinates and their inverse. The models are calibrated with sightings of the Sun, the Moon and a few bright stars. The methods are applied and tested in a case study. Four persistent contrails crossing each other, together with a short-lived one, are observed with the cameras. Vertical and horizontal positions of the contrails are determined from the camera images to an accuracy of better than 230 m and horizontal speed to 0.2 m s-1. With this information, the aircraft causing the contrails are identified by comparison to traffic waypoint data. The observations are compared with synthetic camera pictures of contrails simulated with the contrail prediction model CoCiP, a Lagrangian model using air traffic movement data and numerical weather prediction (NWP) data as input. The results provide tests for the NWP and contrail models. The cameras show spreading and thickening contrails, suggesting ice-supersaturation in the ambient air. The ice-supersaturated layer is found thicker and more humid in this case than predicted by the NWP model used. The simulated and observed contrail positions agree up to differences caused by uncertain wind data. The contrail widths, which depend on wake vortex spreading, ambient shear and turbulence, were partly wider than simulated.

  7. Report of the Expanded Tax Base Study.

    ERIC Educational Resources Information Center

    Lamitie, Robert E.; And Others

    The partial financing of New York State's public schools with a state-mandated tax coupled with state aid based upon county or regional wealth rather than local district wealth would provide greater equalization of both revenues and expenditures of school districts than does the present law. A comparable increase in state aid appropriations under…

  8. Undulator based beamline studies on U5

    NASA Astrophysics Data System (ADS)

    McDonnell, L.; Johnson, P.; Klaffky, R. W.; Smith, N. V.

    An undulator installed on beamline U5 at NSLS is expected to produce an intense flux of photons into a highly collimated beam. At normal operating energies (750 MeV) the FEL undulator is expected to have a fundamental harmonic at wavelength lambda = 300A for magnetic strength parameter K = 1. A simple beamline has been constructed to allow measurements of the absolute photon flux available from this device at wavelengths in the long wavelength tail of the fundamental. The central element of this beamline is a small monochromator based on the chromatic aberration properties of a LiF lens. This lens focuses different wavelengths at different points along the optical axis and monochromatization is achieved by moving the lens to focus different wavelengths onto a fixed 200 microns wide exit slit. Photoelectron spectroscopy was carried out with a CMA; photoelectrons being ejected from a freshly evaporated gold surface. Examination of a typical series of EDC's recorded on this system allows measurements of the bandwidth of the monochromator to be made. By measuring the total yield of electrons from the surface and comparing with previously published electron yield measurements from the same surface it is possible to obtain the total flux of photons from the undultor source.

  9. Study Of Heating Of The Base Region Of A Rocket

    NASA Technical Reports Server (NTRS)

    Ascoli, Edward P.; Heiba, Adel A.; Hsu, Yann-Fu; Lagnado, Ronald R.; Lynch, Edward D.; Ungewitter, Ronald J.

    1994-01-01

    Report describes theoretical study of heating in base region of proposed rocket called "NLS 1.5 stage reference vehicle." Study employed approach based on computational fluid dynamics (CFD). Involved numerical simulations of flow field in base region and in main exhaust plume of cluster of six engines with heat shields.

  10. 30 WS North Base Wind Study

    NASA Technical Reports Server (NTRS)

    Wheeler, Mark

    2011-01-01

    The 30 Weather Squadron (30 WS) is concerned about strong winds observed at their northern towers without advance warning. They state that terrain influences along the extreme northern fringes of Vandenberg Air Force Base (VAFB) make it difficult for forecasters to issue timely and accurate high wind warnings for northeasterly wind events. These events tend to occur during the winter or early spring when they are under the influence of the Great Basin high pressure weather regime. The Launch Weather Officers (LWOs) have seen these rapid wind increases in the current northern Towers 60, 70 and 71 in excess of their 35 kt operational warning threshold. For this task, the 30 WS requested the Applied Meteorology Unit (AMU) analyze data from days when these towers reported winds in excess of 35 kt and determine if there were any precursors in the observations that would allow the LWOs to better forecast and warn their operational customers for these wind events. The 30 WS provided wind tower data for the cool season (October - March) from the period January 2004-March 20 IO. The AMU decoded and evaluated the wind tower data for 66 days identified by the 30 WS as having high-wind events. Out of the 66 event days, only 30 had wind speed observations of > or =35 kt from at least one of the three northern towers. The AMU analyzed surface and upper air charts to determine the synoptic conditions for each event day along with tower peak wind speed and direction time series and wind rose charts for all 30 event days. The analysis revealed a trend on all event days in which the tower winds shifted to the northeast for a period of time before the first recorded > or =35 kt wind speed. The time periods for the 30 event days ranged from 20 minutes to several hours, with a median value of 110 minutes. This trend, if monitored, could give the 30 WS forecasters a precursor to assist in issuing an operational warning before a high wind event occurs. The AMU recommends developing a

  11. Small Study Supports New Stool-Based Colon Cancer Test

    MedlinePlus

    ... gov/news/fullstory_158388.html Small Study Supports New Stool-Based Colon Cancer Test Cologuard may help ... 2016 TUESDAY, April 19, 2016 (HealthDay News) -- A new, but small, study finds more evidence that a ...

  12. Arts-Based Self-Study: Documenting the Ripple Effect

    ERIC Educational Resources Information Center

    Weber, Sandra

    2014-01-01

    Like all forms of inquiry, arts-based self-study research can have unexpected consequences. Although we may start out with a fairly clear objective, the data we generate through arts-based methods might address other questions that are even more important than the ones we thought to ask initially, and our study might have an impact that extends…

  13. ASSESSMENT OF VENTILATION SYSTEMS AS RELATED TO THE BASE STUDY

    EPA Science Inventory

    The U.S. EPA's Office of Radiation and Indoor Air studied 100 public and private office buildings across the U.S. from 1994 1998. The purpose of the study, entitled the Building Assessment Survey and Evaluation (BASE) Study, was to: (a) provide a distribution of indoor air quali...

  14. Space station accommodations for lunar base elements: A study

    NASA Technical Reports Server (NTRS)

    Weidman, Deene J.; Cirillo, William; Llewellyn, Charles; Kaszubowski, Martin; Kienlen, E. Michael, Jr.

    1987-01-01

    The results of a study conducted at NASA-LaRC to assess the impact on the space station of accommodating a Manned Lunar Base are documented. Included in the study are assembly activities for all infrastructure components, resupply and operations support for lunar base elements, crew activity requirements, the effect of lunar activities on Cape Kennedy operations, and the effect on space station science missions. Technology needs to prepare for such missions are also defined. Results of the study indicate that the space station can support the manned lunar base missions with the addition of a Fuel Depot Facility and a heavy lift launch vehicle to support the large launch requirements.

  15. Arts-Based Learning and Leadership Development: A Case Study

    ERIC Educational Resources Information Center

    Brenner, Michael Yoel

    2010-01-01

    This qualitative case study was designed to explore how participants in an arts-based leadership development program learned to draw on their right brain capabilities in order to develop the creative competencies required to solve complex modern-day problems in new and different ways. The rationale for this study emerges from the researcher's…

  16. INTEGRATED GENOME-BASED STUDIES OF SHEWANELLA ECOPHYSIOLOGY

    SciTech Connect

    TIEDJE, JAMES M; KONSTANTINIDIS, KOSTAS; WORDEN, MARK

    2014-01-08

    The aim of the work reported is to study Shewanella population genomics, and to understand the evolution, ecophysiology, and speciation of Shewanella. The tasks supporting this aim are: to study genetic and ecophysiological bases defining the core and diversification of Shewanella species; to determine gene content patterns along redox gradients; and to Investigate the evolutionary processes, patterns and mechanisms of Shewanella.

  17. DOCUMENTATION OF THE DATA BASE: WISCONSIN POWER PLANT IMPACT STUDY

    EPA Science Inventory

    This volume describes the data base of the first phase of the Wisconsin power plant impact study. Data were collected by investigators at the University of Wisconsin-Madison from 1971 to 1978 during their study of the Columbia Generating Station near Portage, Wisconsin. This volu...

  18. StudySearch: a web-based application for posting and searching clinical research studies

    PubMed Central

    Gonsenhauser, Blair; Hallarn, Rose; Carpenter, Daniel; Para, Michael F; Reider, Carson R

    2016-01-01

    Participant accrual into research studies is critical to advancing clinical and translational research to clinical care. Without sufficient recruitment, the purpose of any research study cannot be realized; yet, low recruitment and enrollment of participants persist. StudySearch is a web-based application designed to provide an easily readable, publicly accessible, and searchable listing of IRB-approved protocols that are accruing study participants. The Regulatory, Recruitment and Biomedical Informatics Cores of the Center for Clinical and Translational Science (CCTS) at The Ohio State University developed this research study posting platform. Postings include basic descriptive information: study title, purpose of the study, eligibility criteria and study personnel contact information. Language concerning benefits and/or inducements is not included; therefore, while IRB approval for a study to be listed on StudySearch is required, IRB approval of the posted language is not. Studies are listed by one of two methods; one automated and one manual: (1). Studies registered on ClinicalTrials.gov are automatically downloaded once a month; or (2). Studies are submitted directly by researchers to the CCTS Regulatory Core staff. In either case, final language is a result of an iterative process between researchers and CCTS staff. Deployed in January 2011 at OSU, this application has grown to approximately 200 studies currently posted and 1500 unique visitors per month. Locally, StudySearch is part of the CCTS recruitment toolkit. Features continue to be modified to better accommodate user behaviors. Nationally, this open source application is available for use. PMID:26912012

  19. StudySearch: a web-based application for posting and searching clinical research studies.

    PubMed

    Gonsenhauser, Blair; Hallarn, Rose; Carpenter, Daniel; Para, Michael F; Reider, Carson R

    2016-03-01

    Participant accrual into research studies is critical to advancing clinical and translational research to clinical care. Without sufficient recruitment, the purpose of any research study cannot be realized; yet, low recruitment and enrollment of participants persist. StudySearch is a web-based application designed to provide an easily readable, publicly accessible, and searchable listing of IRB-approved protocols that are accruing study participants. The Regulatory, Recruitment and Biomedical Informatics Cores of the Center for Clinical and Translational Science (CCTS) at The Ohio State University developed this research study posting platform. Postings include basic descriptive information: study title, purpose of the study, eligibility criteria and study personnel contact information. Language concerning benefits and/or inducements is not included; therefore, while IRB approval for a study to be listed on StudySearch is required, IRB approval of the posted language is not. Studies are listed by one of two methods; one automated and one manual: (1). Studies registered on ClinicalTrials.gov are automatically downloaded once a month; or (2). Studies are submitted directly by researchers to the CCTS Regulatory Core staff. In either case, final language is a result of an iterative process between researchers and CCTS staff. Deployed in January 2011 at OSU, this application has grown to approximately 200 studies currently posted and 1500 unique visitors per month. Locally, StudySearch is part of the CCTS recruitment toolkit. Features continue to be modified to better accommodate user behaviors. Nationally, this open source application is available for use. PMID:26912012

  20. Using Case Studies in Calculus-based Physics

    NASA Astrophysics Data System (ADS)

    Katz, Debora M.

    2006-12-01

    Do your students believe that the physics only works in your classroom or laboratory? Or do they see that physics underlies their everyday experience? Case studies in physics help students connect physics principles to their everyday experience. For decades, case studies have been used to teach law, medicine and biology, but they are rarely used in physics. I am working on a calculus-based physics textbook for scientists and engineers. Case studies are woven into each chapter. Stop by and get a case study to test out in your classroom. I would love to get your feedback.

  1. Image based 3D city modeling : Comparative study

    NASA Astrophysics Data System (ADS)

    Singh, S. P.; Jain, K.; Mandla, V. R.

    2014-06-01

    3D city model is a digital representation of the Earth's surface and it's related objects such as building, tree, vegetation, and some manmade feature belonging to urban area. The demand of 3D city modeling is increasing rapidly for various engineering and non-engineering applications. Generally four main image based approaches were used for virtual 3D city models generation. In first approach, researchers were used Sketch based modeling, second method is Procedural grammar based modeling, third approach is Close range photogrammetry based modeling and fourth approach is mainly based on Computer Vision techniques. SketchUp, CityEngine, Photomodeler and Agisoft Photoscan are the main softwares to represent these approaches respectively. These softwares have different approaches & methods suitable for image based 3D city modeling. Literature study shows that till date, there is no complete such type of comparative study available to create complete 3D city model by using images. This paper gives a comparative assessment of these four image based 3D modeling approaches. This comparative study is mainly based on data acquisition methods, data processing techniques and output 3D model products. For this research work, study area is the campus of civil engineering department, Indian Institute of Technology, Roorkee (India). This 3D campus acts as a prototype for city. This study also explains various governing parameters, factors and work experiences. This research work also gives a brief introduction, strengths and weakness of these four image based techniques. Some personal comment is also given as what can do or what can't do from these softwares. At the last, this study shows; it concluded that, each and every software has some advantages and limitations. Choice of software depends on user requirements of 3D project. For normal visualization project, SketchUp software is a good option. For 3D documentation record, Photomodeler gives good result. For Large city

  2. The Inclusion of African-American Study Participants in Web-Based Research Studies: Viewpoint

    PubMed Central

    Harker, Laura; Arriola, Kimberly R. Jacob

    2016-01-01

    The use of Web-based methods for research recruitment and intervention delivery has greatly increased as Internet usage continues to grow. These Internet-based strategies allow for researchers to quickly reach more people. African-Americans are underrepresented in health research studies. Due to this, African-Americans get less benefit from important research that could address the disproportionate health outcomes they face. Web-based research studies are one promising way to engage more African-Americans and build trust with the African-American community. With African-Americans’ increasing access to the Internet using mobile phones and other mobile phone technologies, we advocate for efforts to increase the representation of African-Americans in research studies by using the Internet as a recruitment tool and conclude with recommendations that support this goal. PMID:27334683

  3. The Inclusion of African-American Study Participants in Web-Based Research Studies: Viewpoint.

    PubMed

    Watson, Bekeela; Robinson, Dana H Z; Harker, Laura; Arriola, Kimberly R Jacob

    2016-01-01

    The use of Web-based methods for research recruitment and intervention delivery has greatly increased as Internet usage continues to grow. These Internet-based strategies allow for researchers to quickly reach more people. African-Americans are underrepresented in health research studies. Due to this, African-Americans get less benefit from important research that could address the disproportionate health outcomes they face. Web-based research studies are one promising way to engage more African-Americans and build trust with the African-American community. With African-Americans' increasing access to the Internet using mobile phones and other mobile phone technologies, we advocate for efforts to increase the representation of African-Americans in research studies by using the Internet as a recruitment tool and conclude with recommendations that support this goal. PMID:27334683

  4. A Brief Study on Autonomous Learning Mode in Self-study Center Based on Web

    NASA Astrophysics Data System (ADS)

    Tian, Xian Zhi

    In the paper, the author has studied the autonomous learning ability and its reform of linguistic-major students. All of the studies are based on web in self-study center. As for the author, she has used the method of comparison and at the same time, she also used showing examples. In order to show the views clearly, the author has made investigation in English major and law major students. Thus she thinks that teaching reform is necessary for development of students and some effective ways can be used in improving teaching efficiency.

  5. Review of genotoxicity biomonitoring studies of glyphosate-based formulations

    PubMed Central

    Kier, Larry D.

    2015-01-01

    Abstract Human and environmental genotoxicity biomonitoring studies involving exposure to glyphosate-based formulations (GBFs) were reviewed to complement an earlier review of experimental genotoxicity studies of glyphosate and GBFs. The environmental and most of the human biomonitoring studies were not informative because there was either a very low frequency of GBF exposure or exposure to a large number of pesticides without analysis of specific pesticide effects. One pesticide sprayer biomonitoring study indicated there was not a statistically significant relationship between frequency of GBF exposure reported for the last spraying season and oxidative DNA damage. There were three studies of human populations in regions of GBF aerial spraying. One study found increases for the cytokinesis-block micronucleus endpoint but these increases did not show statistically significant associations with self-reported spray exposure and were not consistent with application rates. A second study found increases for the blood cell comet endpoint at high exposures causing toxicity. However, a follow-up to this study 2 years after spraying did not indicate chromosomal effects. The results of the biomonitoring studies do not contradict an earlier conclusion derived from experimental genotoxicity studies that typical GBFs do not appear to present significant genotoxic risk under normal conditions of human or environmental exposures. PMID:25687244

  6. Study of risk based on web software testing

    NASA Astrophysics Data System (ADS)

    Wang, Xin

    2013-03-01

    Web-based test systems that have particular difficulties and challenges, The article points out a Web application system security risk, through the analysis of the implementation issues involved Web-based testing, proposed workflow based on Web test, And how to choose the risk of the process by adding a detailed study, Discussed the security, performance, accuracy, compatibility, reliability and other details of the risk factors. These risks need for Web application testing program be established in order to make better Web-based test plan.

  7. Combined thermodynamic study of nickel-base alloys. Progress report

    SciTech Connect

    Brooks, C. R.; Meschter, P. J.

    1981-02-15

    Achievements during this period are the following: (1) initiation of a high-temperature study of the Ni-Ta system using the galvanic cell technique, (2) emf study of high-temperature thermodynamics in the Ni-Mo system, (3) measured heat capacity data on ordered and disordered Ni/sub 4/Mo, (4) heat capacities of Ni and disordered Ni/sub 3/Fe, and (5) computer correlation of thermodynamic and phase diagram data in binary Ni-base alloys. (MOW)

  8. Problem-Based Learning: Case Studies, Experience and Practice. Case Studies of Teaching in Higher Education.

    ERIC Educational Resources Information Center

    Schwartz, Peter, Ed.; Mennin, Stewart, Ed.; Webb, Graham, Ed.

    The case studies in this book consider many of the most important issues perceived and experienced by people who are using or developing problem-based learning (PBL). The book focuses on politics, administration, resources, the roles of teachers, and the effects of PBL on students. The chapters are: (1) "Come and See the Real Thing" (David…

  9. Importance of population-based studies in clinical practice

    PubMed Central

    Ronnie, George; Ve, Ramesh Sathyamangalam; Velumuri, Lokapavani; Asokan, Rashima; Vijaya, Lingam

    2011-01-01

    In the last decade, there have been reports on the prevalence of glaucoma from the Vellore Eye Survey, Andhra Pradesh Eye Diseases Survey, Aravind Comprehensive Eye Survey, Chennai Glaucoma Study and West Bengal Glaucoma Study. Population-based studies provide important information regarding the prevalence and risk factors for glaucoma. They also highlight regional differences in the prevalence of various types of glaucoma. It is possible to gather important insights regarding the number of persons affected with glaucoma and the proportion with undiagnosed disease. We reviewed the different population-based studies from India and compare their findings. The lacunae in ophthalmic care that can be inferred from these studies are identified and possible reasons and solutions are discussed. We also discuss the clinical relevance of the various findings, and how it reflects on clinical practice in the country. Since India has a significantly high disease burden, we examine the possibility of population-based screening for disease in the Indian context. PMID:21150021

  10. The Effectiveness of Web-Based Instruction: A Case Study.

    ERIC Educational Resources Information Center

    White, Sylvia E.

    A case study compared web-based and classroom instruction. Subjects, 40 students enrolled in a Communication Technology and Change class, were divided by volunteers into an Internet section (16 students) and a regular classroom section (24 students.) Results indicated that in all cases the classroom section performed slightly better than the…

  11. A Multidisciplinary Osteoporosis Service-Based Action Research Study

    ERIC Educational Resources Information Center

    Whitehead, Dean; Keast, John; Montgomery, Val; Hayman, Sue

    2004-01-01

    Objective: To investigate an existing Trust-based osteoporosis service's preventative activity, determine any issues and problems and use this data to reorganise the service, as part of a National Health Service Executive/Regional Office-commissioned and funded study. Setting: A UK Hospital Trust's Osteoporosis Service. Design & Method: A…

  12. Community Based Child Advocacy Projects: A Study in Evaluation.

    ERIC Educational Resources Information Center

    Kamerman, Sheila B.

    This report describes a study of 23 community-based child advocacy projects, located in 14 states and 20 cities, and outlines a strategy for evaluating such projects. Data on each project's history, development, and current activities were obtained. Data were analyzed to (1) determine how such projects are started and become operational, (2)…

  13. Inquiry-Based Field Studies Involving Teacher-Scientist Collaboration.

    ERIC Educational Resources Information Center

    Odom, Arthur Louis

    2001-01-01

    Describes a collaborative professional development program, Inquiry-Based Field Studies Involving Teacher-Scientist Collaboration, that uses scientist-teacher teams to improve teachers' understanding of scientific inquiry. Reports that the project allowed teachers to develop a deeper understanding on the nature of science. (Author/YDS)

  14. A Computer-Based System for Studies in Learning.

    ERIC Educational Resources Information Center

    Gentner, Donald R.; And Others

    A computer-based system, called the FLOW system, was used in experimental studies of human learning. The student learns a simple computer language from printed instructions and can run his programs interactively on the FLOW system. An automated tutor simulates a human tutor who watches over the student and gives help when the student has…

  15. PAC Studies on Zr-Based Intermetallic Compounds

    NASA Astrophysics Data System (ADS)

    Damonte, L. C.; Mendoza-Zélis, L. A.

    2004-11-01

    The Zr2Al, Zr3Al2 and Zr6NiAl2 intermetallic compounds were characterized by means of time differential perturbed angular correlation (TDPAC) and X-ray diffraction. Our interest in these Zr(Hf) aluminides comes from crystallization studies of Zr(Hf)-based bulk metallic glasses which have a wide supercooled liquid region.

  16. Explorations in Using Arts-Based Self-Study Methods

    ERIC Educational Resources Information Center

    Samaras, Anastasia P.

    2010-01-01

    Research methods courses typically require students to conceptualize, describe, and present their research ideas in writing. In this article, the author describes her exploration in using arts-based techniques for teaching research to support the development of students' self-study research projects. The pedagogical approach emerged from the…

  17. Project-Based Learning in Electronic Technology: A Case Study

    ERIC Educational Resources Information Center

    Li, Li

    2015-01-01

    A case study of project-based learning (PBL) implemented in Tianjin University of Technology and Education is presented. This multidiscipline project is innovated to meet the novel requirements of industry while keeping its traditional effectiveness in driving students to apply knowledge to practice and problem-solving. The implementation of PBL…

  18. Multiple tutorial-based assessments: a generalizability study

    PubMed Central

    2014-01-01

    Background Tutorial-based assessment commonly used in problem-based learning (PBL) is thought to provide information about students which is different from that gathered with traditional assessment strategies such as multiple-choice questions or short-answer questions. Although multiple-observations within units in an undergraduate medical education curriculum foster more reliable scores, that evaluation design is not always practically feasible. Thus, this study investigated the overall reliability of a tutorial-based program of assessment, namely the Tutotest-Lite. Methods More specifically, scores from multiple units were used to profile clinical domains for the first two years of a system-based PBL curriculum. Results G-Study analysis revealed an acceptable level of generalizability, with g-coefficients of 0.84 and 0.83 for Years 1 and 2, respectively. Interestingly, D-Studies suggested that as few as five observations over one year would yield sufficiently reliable scores. Conclusions Overall, the results from this study support the use of the Tutotest-Lite to judge clinical domains over different PBL units. PMID:24528493

  19. Discourse-Based Language Intervention: An Efficacy Study.

    ERIC Educational Resources Information Center

    Skarakis-Doyle, Elizabeth; Murphy, Lisa

    1995-01-01

    This study of a 5-year-old girl with sensorineural hearing loss examined the effect of supplementing a pragmatically based procedure of focused stimulation with structured opportunities for verbal practice using vertical constructions. Results indicated that focused stimulation was an effective treatment procedure, especially when enhanced by the…

  20. Calculus-Based Physics Exploratory Study. Summary Report.

    ERIC Educational Resources Information Center

    Illinois Mathematics and Science Academy, Aurora.

    Generally, the levels of participation and achievement of females in science do not match those of male learners. This report describes the formation and study of an all-female section of calculus-based physics for the purpose of providing an environment that might enhance the participation and achievement of females in the physical sciences so…

  1. A Usability Study of Interactive Web-Based Modules

    ERIC Educational Resources Information Center

    Girard, Tulay; Pinar, Musa

    2011-01-01

    This research advances the understanding of the usability of marketing case study modules in the area of interactive web-based technologies through the assignment of seven interactive case modules in a Principles of Marketing course. The case modules were provided for marketing students by the publisher, McGraw Hill Irwin, of the "Marketing"…

  2. Ontology-based federated data access to human studies information.

    PubMed

    Sim, Ida; Carini, Simona; Tu, Samson W; Detwiler, Landon T; Brinkley, James; Mollah, Shamim A; Burke, Karl; Lehmann, Harold P; Chakraborty, Swati; Wittkowski, Knut M; Pollock, Brad H; Johnson, Thomas M; Huser, Vojtech

    2012-01-01

    Human studies are one of the most valuable sources of knowledge in biomedical research, but data about their design and results are currently widely dispersed in siloed systems. Federation of these data is needed to facilitate large-scale data analysis to realize the goals of evidence-based medicine. The Human Studies Database project has developed an informatics infrastructure for federated query of human studies databases, using a generalizable approach to ontology-based data access. Our approach has three main components. First, the Ontology of Clinical Research (OCRe) provides the reference semantics. Second, a data model, automatically derived from OCRe into XSD, maintains semantic synchrony of the underlying representations while facilitating data acquisition using common XML technologies. Finally, the Query Integrator issues queries distributed over the data, OCRe, and other ontologies such as SNOMED in BioPortal. We report on a demonstration of this infrastructure on data acquired from institutional systems and from ClinicalTrials.gov. PMID:23304360

  3. Ontology-Based Federated Data Access to Human Studies Information

    PubMed Central

    Sim, Ida; Carini, Simona; Tu, Samson W.; Detwiler, Landon T.; Brinkley, James; Mollah, Shamim A.; Burke, Karl; Lehmann, Harold P.; Chakraborty, Swati; Wittkowski, Knut M.; Pollock, Brad H.; Johnson, Thomas M.; Huser, Vojtech

    2012-01-01

    Human studies are one of the most valuable sources of knowledge in biomedical research, but data about their design and results are currently widely dispersed in siloed systems. Federation of these data is needed to facilitate large-scale data analysis to realize the goals of evidence-based medicine. The Human Studies Database project has developed an informatics infrastructure for federated query of human studies databases, using a generalizable approach to ontology-based data access. Our approach has three main components. First, the Ontology of Clinical Research (OCRe) provides the reference semantics. Second, a data model, automatically derived from OCRe into XSD, maintains semantic synchrony of the underlying representations while facilitating data acquisition using common XML technologies. Finally, the Query Integrator issues queries distributed over the data, OCRe, and other ontologies such as SNOMED in BioPortal. We report on a demonstration of this infrastructure on data acquired from institutional systems and from ClinicalTrials.gov. PMID:23304360

  4. Dynamic 1H NMR Studies of Schiff Base Derivatives

    NASA Astrophysics Data System (ADS)

    Köylü, M. Z.; Ekinci, A.; Böyükata, M.; Temel, H.

    2016-01-01

    The spin-lattice relaxation time T 1 and the spin-spin relaxation time T 2 of two Schiff base derivatives, N,N'-ethylenebis(salicylidene)-1,2-diaminoethane (H2L1) and N,N'-ethylenebis (salicylidene)-1,3-diaminopropane (H2L2), in DMSO-d6 solvent were studied as a function of temperature in the range of 20-50°C using a Bruker Avance 400.132 MHz 1H NMR spectrometer. Based on the activation energy ( E a) and correlation time (τc), we believe that the Schiff base derivatives perform a molecular tumbling motion.

  5. Study of systems and techniques for data base management

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Data management areas were studied to identify pertinent problems and issues that will affect future NASA data users in terms of performance and cost. Specific topics discussed include the identifications of potential NASA data users other than those normally discussed, consideration affecting the clustering of minicomputers, low cost computer system for information retrieval and analysis, the testing of minicomputer based data base management systems, ongoing work related to the use of dedicated systems for data base management, and the problems of data interchange among a community of NASA data users.

  6. A population-based cohort study of oral health in South Brazil: The Porto Alegre Study.

    PubMed

    Haas, Alex Nogueira; Gaio, Eduardo José; Wagner, Marcius Comparsi; Rios, Fernando Silva; Costa, Ricardo dos Santos Araujo; Rösing, Cassiano Kuchenbecker; Oppermann, Rui Vicente; Albandar, Jasim; Susin, Cristiano

    2015-01-01

    Few population-based cohort studies have been established in Dentistry and this is especially true for Latin America. We conducted a population-based prospective study focusing on oral health in Porto Alegre, south Brazil, and herein we describe its methodology and discuss directions for further research. The cohort was established in 2001 using a multistage probability sample of 1,465 toothed and 121 edentulous subjects. A 5-year follow-up was performed in 2006 that included 755 individuals. The main aim of this study was to determine the pattern and risk factors for periodontal disease progression and tooth loss incidence. A full-mouth protocol was used including periodontal assessments at six sites per tooth. Primary outcomes were periodontal attachment loss and tooth loss. Oral mucosal lesions, dental plaque, gingivitis, supragingival calculus, probing depths, gingival recession, and dental caries were also assessed. This is the first population-based cohort study to focus on periodontal disease in Latin America. Findings will contribute to our understanding of the epidemiology of periodontal disease and provide valuable data for the planning and implementation of preventive and therapeutic strategies. PMID:26083520

  7. Agenda-Based Regulation of Study-Time Allocation: When Agendas Override Item-Based Monitoring

    ERIC Educational Resources Information Center

    Ariel, Robert; Dunlosky, John; Bailey, Heather

    2009-01-01

    Theories of self-regulated study assume that learners monitor item difficulty when making decisions about which items to select for study. To complement such theories, the authors propose an agenda-based regulation (ABR) model in which learners' study decisions are guided by an agenda that learners develop to prioritize items for study, given…

  8. Epidemiological study of prostate cancer (EPICAP): a population-based case–control study in France

    PubMed Central

    2014-01-01

    Background Prostate cancer is the most common cancer in male in most Western countries, including France. Despite a significant morbidity and mortality to a lesser extent, the etiology of prostate cancer remains largely unknown. Indeed, the only well-established risk factors to date are age, ethnicity and a family history of prostate cancer. We present, here, the rationale and design of the EPIdemiological study of Prostate CAncer (EPICAP), a population-based case–control study specifically designed to investigate the role of environmental and genetic factors in prostate cancer. The EPICAP study will particularly focused on the role of circadian disruption, chronic inflammation, hormonal and metabolic factors in the occurrence of prostate cancer. Methods/Design EPICAP is a population-based case–control study conducted in the département of Hérault in France. Eligible cases are all cases of prostate cancers newly diagnosed in 2012-2013 in men less than 75 years old and residing in the département of Hérault at the time of diagnosis. Controls are men of the same age as the cases and living in the département of Hérault, recruited in the general population. The sample will include a total of 1000 incident cases of prostate cancer and 1000 population-based controls over a 3-year period (2012-2014). The cases and controls are face-to-face interviewed using a standardized computed assisted questionnaire. The questions focus primarily on usual socio-demographic characteristics, personal and family medical history, lifestyle, leisure activities, residential and occupational history. Anthropometric measures and biological samples are also collected for cases and controls. Discussion The EPICAP study aims to answer key questions in prostate cancer etiology: (1) role of circadian disruption through the study of working hours, chronotype and duration/quality of sleep, (2) role of chronic inflammation and anti-inflammatory drugs, (3) role of hormonal and metabolic

  9. Reduced bases for nonlinear structural dynamic systems: A comparative study

    NASA Astrophysics Data System (ADS)

    Lülf, Fritz Adrian; Tran, Duc-Minh; Ohayon, Roger

    2013-07-01

    The presented work provides an overview of some commonly used approaches for generating reduced bases for discrete nonlinear dynamic systems. It investigates the performance and the robustness of these bases if they are applied in a reduction-by-projection procedure on different test cases. The bases are created from the Linear Normal Modes, the Ritz-vectors, the Proper and the Smooth Orthogonal Decomposition method, the A Priori Reduction, the Centroidal Voronoi Tessellation and the Local Equivalent Linear Stiffness Method. Second-Order Terms and an Enhanced Proper Orthogonal Decomposition formulation are included as variants. The test cases are small dimensional, locally or entirely nonlinear system subjected to a harmonic or an impulse force excitation. The double objective of this numerical study is, first, to determine which bases are most adequate for a given combination of nonlinearity and excitation and, second, to which extend the bases exhibit an inherent robustness if the parameterisation of the excitation is changed. A specific multicriteria decision analysis score is developed to assess the bases' performance. As a major result, a strong dependence of the performance of the bases on the type of excitation is established and thus some bases become more adequate for a certain situation than others. Also a lack of robustness for all considered bases can be observed. This situation improves in most cases if the basis is generated with the most critical values of the parameter.

  10. Vegetation studies on Vandenberg Air Force Base, California

    NASA Technical Reports Server (NTRS)

    Schmalzer, Paul A.; Hickson, Diana E.; Hinkle, C. Ross

    1988-01-01

    Vandenburg Air Force Base, located in coastal central California with an area of 98,400 ac, contains resources of considerable biological significance. Available information on the vegetation and flora of Vandenburg is summarized and new data collected in this project are presented. A bibliography of 621 references dealing with vegetation and related topics related to Vanderburg was compiled from computer and manual literature searches and a review of past studies of the base. A preliminary floristic list of 642 taxa representing 311 genera and 80 families was compiled from past studies and plants identified in the vegetation sampling conducted in this project. Fifty-two special interest plant species are known to occur or were suggested to occur. Vegetation was sampled using permanent plots and transects in all major plant communities including chaparral, Bishop pine forest, tanbark oak forest, annual grassland, oak woodland, coastal sage scrub, purple sage scrub, coastal dune scrub, coastal dunes, box elder riparian woodland, will riparian woodland, freshwater marsh, salt marsh, and seasonal wetlands. Comparison of the new vegetation data to the compostie San Diego State University data does not indicate major changes in most communities since the original study. Recommendations are made for additional studies needed to maintain and extend the environmental data base and for management actions to improve resource protection.

  11. Earth & Space-Based Power Generation Systems - A Comparison Study

    NASA Astrophysics Data System (ADS)

    Zerta, M.; Blandow, V.; Collins, P.; Guillet, J.; Nordmann, Thomas; Schmidt, Patrick; Weindorf, Werner; Zittel, Werner

    2004-12-01

    The objective of the study [1] is to comparatively assess the economic viability, energy investment, risk and reliability issues of broad-scale introduction of terrestrial and space based solar power systems for a European power supply in 2030 at various scenario power levels. The scenario design in terms of base load and non-base load cases is only suited to gain principle knowledge about both terrestrial and space-based solar power system architectures. The comparative cost, energy, risk and reliability discussions and evaluations are based on highly asymmetrical input data due to different magnitudes of practical experiences. However, under the study assumptions given, space- based solar power systems may potentially provide a firm power supply and could be economically competitive to terrestrial solar power systems if space transportation costs in the lower hundreds EUR/kg payload are achieved. The energy payback time could be in the range of other solar power technologies far below their operational lifetimes. Risks attributed with SPS are mainly in the field of health and public acceptance of microwave power transmission, the general R&D risk and geopolitical implications.

  12. Partial gravity habitat study: With application to lunar base design

    NASA Technical Reports Server (NTRS)

    Capps, Stephen; Lorandos, Jason; Akhidime, Eval; Bunch, Michael; Lund, Denise; Moore, Nathan; Murakawa, Kio; Bell, Larry; Trotti, Guillermo; Neubek, Deb

    1989-01-01

    Comprehensive design requirements associated with designing habitats for humans in a partial gravity environment were investigated and then applied to a lunar base design. Other potential sites for application include planetary surfaces such as Mars, variable gravity research facilities, or a rotating spacecraft. Design requirements for partial gravity environments include: (1) locomotion changes in less than normal Earth gravity; (2) facility design issues, such as interior configuration, module diameter and geometry; and (3) volumetric requirements based on the previous as well as psychological issues involved in prolonged isolation. For application to a Lunar Base, it was necessary to study the exterior architecture and configuration to insure optimum circulation patterns while providing dual egress. Radiation protection issues were addressed to provide a safe and healthy environment for the crew, and finally, the overall site was studied to locate all associated facilities in context with the habitat. Mission planning was not the purpose of this study; therefore, a Lockheed scenario was used as an outline for the Lunar Base application, which was then modified to meet the project needs.

  13. Evidence-based practice: reflections from five European case studies.

    PubMed

    Baeza, Juan I; Fraser, Alec; Boaz, Annette

    2014-01-01

    Background Evidence-based practice (EBP) is now the accepted orthodoxy in clinical practice and developed from evidence-based medicine. EBP is based on a specific type of evidence that is derived from studies based on randomised controlled trials (RCT). This type of evidence is suited to acute medical care and is more problematic for other clinicians such as nurses and therapists, particularly when they are situated within community or primary care settings. Setting Five stroke care services in England (2), Sweden (2) and Poland (1). Aims To reflect on the evidence gained from these case studies to shed light on various aspects of EBP. This paper focuses on three key issues: (1) the importance of context for evidence, (2) the nature of knowledge, and (3) professional hierarchies. Methods Five qualitative case studies into stroke care were carried out in England, Sweden and Poland. One hundred and twenty semi-structured interviews were carried out with a range of healthcare staff who provided specialised and non-specialised stroke care in acute, community and primary care between October 2010 and September 2011. Medical doctors, nurses and different therapists were included in the samples in all five case studies. For this paper, we reflect on some aspects of this work to illuminate the different interprofessional perspectives relating to EBP in stroke care. Results The lack of RCT-based evidence in the community and primary care sectors can lead to the clinicians working in these sectors being perceived as having a lower status. Clinicians use both tacit and encoded knowledge to guide their practice and there existed both intraand interprofessional tensions in these two types of knowledge. The professional hierarchy of stroke teams varies with national context and the role of the non-specialists is less valued in stroke care. PMID:25949726

  14. Systematic Review of Community-Based Childhood Obesity Prevention Studies

    PubMed Central

    Segal, Jodi; Wu, Yang; Wilson, Renee; Wang, Youfa

    2013-01-01

    OBJECTIVE: This study systematically reviewed community-based childhood obesity prevention programs in the United States and high-income countries. METHODS: We searched Medline, Embase, PsychInfo, CINAHL, clinicaltrials.gov, and the Cochrane Library for relevant English-language studies. Studies were eligible if the intervention was primarily implemented in the community setting; had at least 1 year of follow-up after baseline; and compared results from an intervention to a comparison group. Two independent reviewers conducted title scans and abstract reviews and reviewed the full articles to assess eligibility. Each article received a double review for data abstraction. The second reviewer confirmed the first reviewer’s data abstraction for completeness and accuracy. RESULTS: Nine community-based studies were included; 5 randomized controlled trials and 4 non–randomized controlled trials. One study was conducted only in the community setting, 3 were conducted in the community and school setting, and 5 were conducted in the community setting in combination with at least 1 other setting such as the home. Desirable changes in BMI or BMI z-score were found in 4 of the 9 studies. Two studies reported significant improvements in behavioral outcomes (1 in physical activity and 1 in vegetable intake). CONCLUSIONS: The strength of evidence is moderate that a combined diet and physical activity intervention conducted in the community with a school component is more effective at preventing obesity or overweight. More research and consistent methods are needed to understand the comparative effectiveness of childhood obesity prevention programs in the community setting. PMID:23753099

  15. Complexity analysis of human physiological signals based on case studies

    NASA Astrophysics Data System (ADS)

    Angelova, Maia; Holloway, Philip; Ellis, Jason

    2015-04-01

    This work focuses on methods for investigation of physiological time series based on complexity analysis. It is a part of a wider programme to determine non-invasive markers for healthy ageing. We consider two case studies investigated with actigraphy: (a) sleep and alternations with insomnia, and (b) ageing effects on mobility patterns. We illustrate, using these case studies, the application of fractal analysis to the investigation of regulation patterns and control, and change of physiological function. In the first case study, fractal analysis techniques were implemented to study the correlations present in sleep actigraphy for individuals suffering from acute insomnia in comparison with healthy controls. The aim was to investigate if complexity analysis can detect the onset of adverse health-related events. The subjects with acute insomnia displayed significantly higher levels of complexity, possibly a result of too much activity in the underlying regulatory systems. The second case study considered mobility patterns during night time and their variations with age. It showed that complexity metrics can identify change in physiological function with ageing. Both studies demonstrated that complexity analysis can be used to investigate markers of health, disease and healthy ageing.

  16. Space-Based Gravitational-wave Mission Concept Studies

    NASA Technical Reports Server (NTRS)

    Livas, Jeffrey C.

    2012-01-01

    The LISA Mission Concept has been under study for over two decades as a spacebased gravitational-wave detector capable of observing astrophysical sources in the 0.0001 to 1 Hz band. The concept has consistently received strong recommendations from various review panels based on the expected science, most recently from the US Astr02010 Decadal Review. Budget constraints have led both the US and European Space agencies to search for lower cost options. We report results from the US effort to explore the tradeoffs between mission cost and science return, and in particular a family of mission concepts referred to as SGO (Space-based Gravitational-wave Observatory).

  17. Transgenic animal models of neurodegeneration based on human genetic studies

    PubMed Central

    Richie, Christopher T.; Hoffer, Barry J.; Airavaara, Mikko

    2011-01-01

    The identification of genes linked to neurodegenerative diseases such as Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD) and Parkinson's disease (PD) has led to the development of animal models for studying mechanism and evaluating potential therapies. None of the transgenic models developed based on disease-associated genes have been able to fully recapitulate the behavioral and pathological features of the corresponding disease. However, there has been enormous progress made in identifying potential therapeutic targets and understanding some of the common mechanisms of neurodegeneration. In this review, we will discuss transgenic animal models for AD, ALS, HD and PD that are based on human genetic studies. All of the diseases discussed have active or complete clinical trials for experimental treatments that benefited from transgenic models of the disease. PMID:20931247

  18. Case Studies in Agnotology-Based Learning (Invited)

    NASA Astrophysics Data System (ADS)

    Cook, J.; Bedford, D. P.; Mandia, S. A.

    2013-12-01

    Agnotology is the study of how and why ignorance or misconceptions exist. While misconceptions are a challenge for educators, they also present an opportunity to improve climate literacy through agnotology-based learning. This involves refutational lessons that challenge misconceptions while teaching scientific concepts. I will summarize two decades of research that find refutational texts are among the most effective forms of reducing misconceptions. I will present case studies in improving climate literacy through agnotology-based learning, both in the college classroom and in public outreach promoted through mainstream and social media. I will also explore how content from the SkepticalScience.com website is being used by educators as a teaching resource. These real-world examples demonstrate effective ways to reduce misperceptions and improve climate literacy.

  19. Study of radiation characteristic of airborne sensor based on tarps

    NASA Astrophysics Data System (ADS)

    Yu, Xiujuan; Qi, Weijun; Fang, Aiping

    2014-07-01

    The radiation characteristic of aerial sensor directly affects the quantitative application level of sensor data. In order to study the radiation characteristic, we carried out the radiation characteristic test based on ground tarps laid onto the calibration field of image quality in Anyang, Henan. The airborne sensor was calibrated adopting reflectance-based method. 8 gray-scale tarps and 4 tarps of high reflectance were laid onto the calibration field and they were all with better Lambert radiation characteristic and spectral performance uniformity. Preliminary results show that the bias is larger and the effective dynamic range is smaller and the SNR is lower but the linearity and repeatability are better which can be used to test the response performance of the sensor. Overall, the radiation characteristic tarps laid on the calibration field are suitable for the study of in-flight radiation characteristic of the aerial digital sensor.

  20. Market-Based Indian Grid Integration Study Options: Preprint

    SciTech Connect

    Stoltenberg, B.; Clark, K.; Negi, S. K.

    2012-03-01

    The Indian state of Gujarat is forecasting solar and wind generation expansion from 16% to 32% of installed generation capacity by 2015. Some states in India are already experiencing heavy wind power curtailment. Understanding how to integrate variable generation (VG) into the grid is of great interest to local transmission companies and India's Ministry of New and Renewable Energy. This paper describes the nature of a market-based integration study and how this approach, while new to Indian grid operation and planning, is necessary to understand how to operate and expand the grid to best accommodate the expansion of VG. Second, it discusses options in defining a study's scope, such as data granularity, generation modeling, and geographic scope. The paper also explores how Gujarat's method of grid operation and current system reliability will affect how an integration study can be performed.

  1. Project-based learning in electronic technology: a case study

    NASA Astrophysics Data System (ADS)

    Li, Li

    2015-09-01

    A case study of project-based learning (PBL) implemented in Tianjin University of Technology and Education is presented. This multidiscipline project is innovated to meet the novel requirements of industry while keeping its traditional effectiveness in driving students to apply knowledge to practice and problem-solving. The implementation of PBL is described with emphasis in relation to the ability cultivation. The feedback from students shows positive support for the innovations.

  2. Faith based aviation: An ethnographic study of missionary flights international

    NASA Astrophysics Data System (ADS)

    Cooper, Joseph H.

    The development of faith-based missionary aviation is a post-World War II phenomenon. The war effort demonstrated the value, utility, and global reach of aviation to remote, underdeveloped areas of the world. With the beginnings of a worldwide infrastructure for aviation, Christian aviators realized aviation could increase the range and effectiveness of their efforts to reach the world for Christ (Mellis, 2006). Although individual organizations provide statistical information and data about flight operations there is a lack of external evidence and relevant research literature confirming the scope and value of these faith based aviation organizations and operations. A qualitative, ethnographic study was conducted to document the activities of one faith-based aviation organization to gain an understanding of this little known aspect of civilian aviation. The study was conducted with Missionary Flights International (MFI) of Fort Pierce, FL which has been involved in faith-based, missionary aviation since its inception in 1964. As an aviation organization "MFI strives to offer affiliated missions the kind of efficient service and professionalism expected of an airline operation" (Missionary Flights International, 2013, p.1). MFI is a lifeline for missionaries to Haiti and the Dominican Republic, fulfilling their motto of "Standing in the Gap". MFI provides twice a week service to the island of Hispaniola and the Republic of Haiti. In this in-depth study insight and understanding was gained into the purpose of MFI, their daily routines and operations, and the challenges they face in maintaining their flight services to Haiti. This study provided documentation of the value and utility of such aviation efforts and of the individuals involved in this endeavor.

  3. Learning through Web-Based Multistoryline Case Studies: A Design-Based Research

    ERIC Educational Resources Information Center

    Zeng, Rui; Blasi, Laura

    2010-01-01

    This article describes a design-based research in an undergraduate measurement and evaluation course. The study employed web-based multistoryline case studies grounded on Spiro's cognitive flexibility theory to improve students' comprehension of concepts and knowledge. The findings of this research reveal that students demonstrated positive…

  4. Audio-Based versus Text-Based Asynchronous Online Discussion: Two Case Studies

    ERIC Educational Resources Information Center

    Hew, Khe Foon; Cheung, Wing Sum

    2013-01-01

    The main objective of this paper is to examine the use of audio- versus text-based asynchronous online discussions. We report two case studies conducted within the context of semester-long teacher education courses at an Asian Pacific university. Forty-one graduate students participated in Study I. After the online discussions (both audio-based as…

  5. Social Studies Teachers' Use of Classroom-Based and Web-Based Historical Primary Sources

    ERIC Educational Resources Information Center

    Hicks, David; Doolittle, Peter; Lee, John K.

    2004-01-01

    A limited body of research examines the extent to which social studies teachers are actually utilizing primary sources that are accessible in traditional classroom-based formats versus web-based formats. This paper initiates an exploration of this gap in the literature by reporting on the result of a survey of secondary social studies teachers,…

  6. Feasibility Study of EO SARs as Opportunity Illuminators in Passive Radars: PAZ-Based Case Study.

    PubMed

    Bárcena-Humanes, Jose-Luis; Gómez-Hoyo, Pedro-José; Jarabo-Amores, Maria-Pilar; Mata-Moya, David; Del-Rey-Maestre, Nerea

    2015-01-01

    Passive radars exploit the signal transmitted by other systems, known as opportunity illuminators (OIs), instead of using their own transmitter. Due to its almost total invulnerability to natural disasters or physical attacks, satellite OIs are of special interest. In this line, a feasibility study of Earth Observation Synthetic Aperture Radar (EO SAR) systems as OIs is carried out taking into consideration signal waveform, availability, bistatic geometry, instrumented coverage area and incident power density. A case study based on the use of PAZ, the first Spanish EO SAR, is presented. PAZ transmitted waveform, operation modes, orbit characteristics and antenna and transmitter parameters are analyzed to estimate potential coverages and resolutions. The study concludes that, due to its working in on-demand operating mode, passive radars based on PAZ-type illuminators can be proposed as complementing tools during the sensor commissioning phase, for system maintenance and for improving its performance by providing additional information about the area of interest and/or increasing the data updating speed, exploiting other sensors during the time PAZ is not available. PMID:26593921

  7. Feasibility Study of EO SARs as Opportunity Illuminators in Passive Radars: PAZ-Based Case Study

    PubMed Central

    Bárcena-Humanes, Jose-Luis; Gómez-Hoyo, Pedro-José; Jarabo-Amores, Maria-Pilar; Mata-Moya, David; De-Rey-Maestre, Nerea

    2015-01-01

    Passive radars exploit the signal transmitted by other systems, known as opportunity illuminators (OIs), instead of using their own transmitter. Due to its almost total invulnerability to natural disasters or physical attacks, satellite OIs are of special interest. In this line, a feasibility study of Earth Observation Synthetic Aperture Radar (EO SAR) systems as OIs is carried out taking into consideration signal waveform, availability, bistatic geometry, instrumented coverage area and incident power density. A case study based on the use of PAZ, the first Spanish EO SAR, is presented. PAZ transmitted waveform, operation modes, orbit characteristics and antenna and transmitter parameters are analyzed to estimate potential coverages and resolutions. The study concludes that, due to its working in on-demand operating mode, passive radars based on PAZ-type illuminators can be proposed as complementing tools during the sensor commissioning phase, for system maintenance and for improving its performance by providing additional information about the area of interest and/or increasing the data updating speed, exploiting other sensors during the time PAZ is not available. PMID:26593921

  8. A population-based study of the stratum corneum moisture

    PubMed Central

    de Farias Pires, Thiago; Azambuja, Ana Paula; Horimoto, Andrea Roseli Vançan Russo; Nakamura, Mary Sanae; de Oliveira Alvim, Rafael; Krieger, José Eduardo; Pereira, Alexandre Costa

    2016-01-01

    Background The stratum corneum (SC) has important functions as a bound-water modulator and a primary barrier of the human skin from the external environment. However, no large epidemiological study has quantified the relative importance of different exposures with regard to these functional properties. In this study, we have studied a large sample of individuals from the Brazilian population in order to understand the different relationships between the properties of SC and a number of demographic and self-perceived variables. Methods One thousand three hundred and thirty-nine individuals from a rural Brazilian population, who were participants of a family-based study, were submitted to a cross-sectional examination of the SC moisture by capacitance using the Corneometer® CM820 and investigated regarding environmental exposures, cosmetic use, and other physiological and epidemiological measurements. Self-perception-scaled questions about skin conditions were also applied. Results We found significant associations between SC moisture and sex, age, high sun exposure, and sunscreen use frequency (P<0.025). In specific studied sites, self-reported race and obesity were also found to show significant effects. Dry skin self-perception was also found to be highly correlated with the objective measurement of the skin. Other environmental effects on SC moisture are also reported. PMID:27143945

  9. Cohort profile: The Berlin Aging Study II (BASE-II).

    PubMed

    Bertram, Lars; Böckenhoff, Anke; Demuth, Ilja; Düzel, Sandra; Eckardt, Rahel; Li, Shu-Chen; Lindenberger, Ulman; Pawelec, Graham; Siedler, Thomas; Wagner, Gert G; Steinhagen-Thiessen, Elisabeth

    2014-06-01

    Similar to other industrialized countries, Germany's population is ageing. Whereas some people enjoy good physical and cognitive health into old age, others suffer from a multitude of age-related disorders and impairments which reduce life expectancy and affect quality of life. To identify and characterize the factors associated with 'healthy' vs. 'unhealthy' ageing, we have launched the Berlin Aging Study II (BASE-II), a multidisciplinary and multi-institutional project that ascertains a large number of ageing-related variables from a wide range of different functional domains. Phenotypic assessments include factors related to geriatrics and internal medicine, immunology, genetics, psychology, sociology and economics. Baseline recruitment of the BASE-II cohort was recently completed and has led to the sampling of 1600 older adults (age range 60-80 years), as well as 600 younger adults (20-35 years) serving as the basic population for in-depth analyses. BASE-II data are linked to the German Socio-Economic Panel Study (SOEP), a long-running panel survey representative of the German population, to estimate sample selectivity. A major goal of BASE-II is to facilitate collaboration with other research groups by freely sharing relevant phenotypic and genotypic data with qualified outside investigators. PMID:23505255

  10. Laboratory-Based Studies of Eating among Children and Adolescents.

    PubMed

    Tanofsky-Kraff, Marian; Haynos, Ann F; Kotler, Lisa A; Yanovski, Susan Z; Yanovski, Jack A

    2007-01-01

    The prevalence of pediatric overweight has increased dramatically over the past three decades, likely due to changes in food intake as well as physical activity. Therefore, information examining eating patterns among children and adolescents is needed to illuminate which aspects of eating behavior require modification to prevent and treat pediatric overweight. Because child self-report and parent-report of children's eating habits are often inconsistent and limited by recall and other biases, laboratory-based studies in which food intake is observed and monitored have increased in number. Such studies offer objective and controlled methods of measuring and describing eating behaviors. However, to our knowledge, no publication exists that consolidates, reviews, and provides critical commentary on the literature to date in pediatric samples. In this paper, we review the literature of studies utilizing laboratory methods to examine eating behavior in samples ranging from birth through adolescence. Our review includes all relevant articles retrieved from the PubMed, Medline and PsychInfo search engines. Specifically, we examine meal-feeding studies conducted during the various developmental stages (infancy, preschool, middle childhood, and adolescence), with a focus on methodology. Included in our review are feeding studies related to dietary regulation, exposure and preference, as well as paradigms examining disordered eating patterns and their relationship to body composition. We have structured this review so that both consistent and inconsistent findings are presented by age group, and innovative methods of assessment are discussed in more detail. Following each section, we summarize findings and draw potential conclusions from the available data. We then discuss clinical implications of the research data and suggest directions for the next generation of studies of feeding behavior in children. PMID:19030122

  11. Laboratory-Based Studies of Eating among Children and Adolescents

    PubMed Central

    Tanofsky-Kraff, Marian; Haynos, Ann F.; Kotler, Lisa A.; Yanovski, Susan Z.; Yanovski, Jack A.

    2008-01-01

    The prevalence of pediatric overweight has increased dramatically over the past three decades, likely due to changes in food intake as well as physical activity. Therefore, information examining eating patterns among children and adolescents is needed to illuminate which aspects of eating behavior require modification to prevent and treat pediatric overweight. Because child self-report and parent-report of children's eating habits are often inconsistent and limited by recall and other biases, laboratory-based studies in which food intake is observed and monitored have increased in number. Such studies offer objective and controlled methods of measuring and describing eating behaviors. However, to our knowledge, no publication exists that consolidates, reviews, and provides critical commentary on the literature to date in pediatric samples. In this paper, we review the literature of studies utilizing laboratory methods to examine eating behavior in samples ranging from birth through adolescence. Our review includes all relevant articles retrieved from the PubMed, Medline and PsychInfo search engines. Specifically, we examine meal-feeding studies conducted during the various developmental stages (infancy, preschool, middle childhood, and adolescence), with a focus on methodology. Included in our review are feeding studies related to dietary regulation, exposure and preference, as well as paradigms examining disordered eating patterns and their relationship to body composition. We have structured this review so that both consistent and inconsistent findings are presented by age group, and innovative methods of assessment are discussed in more detail. Following each section, we summarize findings and draw potential conclusions from the available data. We then discuss clinical implications of the research data and suggest directions for the next generation of studies of feeding behavior in children. PMID:19030122

  12. A study of a tissue equivalent gelatine based tissue substitute

    SciTech Connect

    Spence, J.L.

    1992-11-01

    A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it`s usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.

  13. A study of a tissue equivalent gelatine based tissue substitute

    SciTech Connect

    Spence, J.L.

    1992-11-01

    A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it's usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.

  14. X-33 Base Region Thermal Protection System Design Study

    NASA Technical Reports Server (NTRS)

    Lycans, Randal W.

    1998-01-01

    The X-33 is an advanced technology demonstrator for validating critical technologies and systems required for an operational Single-Stage-to-Orbit (SSTO) Reusuable Launch Vehicle (RLV). Currently under development by a unique contractor/government team led by Lockheed- Martin Skunk Works (LMSW), and managed by Marshall Space Flight Center (MSFC), the X-33 will be the prototype of the first new launch system developed by the United States since the advent of the space shuttle. This paper documents a design trade study of the X-33 base region thermal protection system (TPS). Two candidate designs were evaluated for thermal performance and weight. The first candidate was a fully reusable metallic TPS using Inconel honeycomb panels insulated with high temperature fibrous insulation, while the second was an ablator/insulator sprayed on the metallic skin of the vehicle. The TPS configurations and insulation thickness requirements were determined for the predicted main engine plume heating environments and base region entry aerothermal environments. In addition to thermal analysis of the design concepts, sensitivity studies were performed to investigate the effect of variations in key parameters of the base TPS analysis.

  15. Study of operational risk-based configuration control

    SciTech Connect

    Vesely, W E; Samanta, P K; Kim, I S

    1991-08-01

    This report studies aspects of a risk-based configuration control system to detect and control plant configurations from a risk perspective. Configuration control, as the term is used here, is the management of component configurations to achieve specific objectives. One important objective is to control risk and safety. Another is to operate efficiently and make effective use of available resources. PSA-based evaluations are performed to study configuration to core-melt frequency and core-melt probability for two plants. Some equipment configurations can cause large core-melt frequency and there are a number of such configurations that are not currently controlled by technical specifications. However, the expected frequency of occurrence of the impacting configurations is small and the core-melt probability contributions are also generally small. The insights from this evaluation are used to develop the framework for an effective risk-based configuration control system. The focal points of such a system and the requirements for tools development for implementing the system are defined. The requirements of risk models needed for the system, and the uses of plant-specific data are also discussed. 18 refs., 25 figs., 10 tabs.

  16. Fuzzy-based HAZOP study for process industry.

    PubMed

    Ahn, Junkeon; Chang, Daejun

    2016-11-01

    This study proposed a fuzzy-based HAZOP for analyzing process hazards. Fuzzy theory was used to express uncertain states. This theory was found to be a useful approach to overcome the inherent uncertainty in HAZOP analyses. Fuzzy logic sharply contrasted with classical logic and provided diverse risk values according to its membership degree. Appropriate process parameters and guidewords were selected to describe the frequency and consequence of an accident. Fuzzy modeling calculated risks based on the relationship between the variables of an accident. The modeling was based on the mean expected value, trapezoidal fuzzy number, IF-THEN rules, and the center of gravity method. A cryogenic LNG (liquefied natural gas) testing facility was the objective process for the fuzzy-based and conventional HAZOPs. The most significant index is the frequency to determine risks. The comparison results showed that the fuzzy-based HAZOP provides better sophisticated risks than the conventional HAZOP. The fuzzy risk matrix presents the significance of risks, negligible risks, and necessity of risk reduction. PMID:27318726

  17. Feasibility Study for an Asymmetric B Factory Based on PEP

    SciTech Connect

    Chattapadhyay, A.; Hitlin, D.; Porter, F.; Chin, Y.H.; Dell'Orco, D.; Forest, E.; Furman, M.; Garren, A.A.; Hoyer, E.; Kennedy, K.; Lambertson, G.; Lo, C.C.; Nishimura, H.; Oddone, P.; Ronan, M.; Sessler, A.; Taylor, B.; Taylor, C.; Zisman, M.; Barletta, W.; Allen, M.; Bloom, E.; Burke, D.; Cornacchia, M.; Davies-White, D.; Destaebler, H.; Donald, M.H.; Dorfan, J.; Feldman, G.; Rees, J.; Schsarz, H.; Sullivan, M.; Autin, B.; Tennyson, J.; Barbson, B.; Oide, K.

    1989-10-26

    This report addresses the feasibility of designing and constructing an asymmetric B-factory based on the PEP storage ring at SLAC that can ultimately reach a luminosity of 1 X 10{sup 34} cm{sup -2}s{sup -1}. Such a facility, operating at the {gamma}(4S) resonance, could be used to study mixing, rate decays, and CP violation in the B{bar B} system, and could also study tau and charm physics. The essential accelerator physics, engineering, and technology issues that must be addressed to successfully build this exciting and challenging facility are identified, and possible solutions, or R and D that will reasonable lead to such solutions, are described.

  18. Decision tree based transient stability method -- A case study

    SciTech Connect

    Wehenkel, L.; Pavella, M. . Inst. Montefiore); Euxibie, E.; Heilbronn, B. . Direction des Etudes et Recherches)

    1994-02-01

    The decision tree transient stability method is revisited via a case study carried out on the French EHV power system. In short, the method consists of building off-line decision trees, able to subsequently assess the system transient behavior in terms of precontingency parameters (or attributes'') of it, likely to drive the stability phenomena. This case study aims at investigating practical feasibility aspects and features of the trees, at enhancing their reliability to the extent possible, and at generalizing them. Feasibility aspects encompass data base generation, candidate attributes, stability classes; tree features concern in particular complexity in terms of their size and interpretability capabilities, robustness with respect to both their building and use. Reliability is enhanced by defining and exploiting pragmatic quality measures. Generalization concerns multicontingency, instead of single-contingency trees. The results obtained show real promise for the method to meet practical needs of electric power utilities.

  19. Studying inflation with future space-based gravitational wave detectors

    SciTech Connect

    Jinno, Ryusuke; Moroi, Takeo; Takahashi, Tomo E-mail: moroi@phys.s.u-tokyo.ac.jp

    2014-12-01

    Motivated by recent progress in our understanding of the B-mode polarization of cosmic microwave background (CMB), which provides important information about the inflationary gravitational waves (IGWs), we study the possibility to acquire information about the early universe using future space-based gravitational wave (GW) detectors. We perform a detailed statistical analysis to estimate how well we can determine the reheating temperature after inflation as well as the amplitude, the tensor spectral index, and the running of the inflationary gravitational waves. We discuss how the accuracies depend on noise parameters of the detector and the minimum frequency available in the analysis. Implication of such a study on the test of inflation models is also discussed.

  20. Structural Studies of Pterin-Based Inhibitors of Dihydropteroate Synthase

    SciTech Connect

    Hevener, Kirk E.; Yun, Mi-Kyung; Qi, Jianjun; Kerr, Iain D.; Babaoglu, Kerim; Hurdle, Julian G.; Balakrishna, Kanya; White, Stephan W.; Lee, Richard E.

    2010-01-12

    Dihydropteroate synthase (DHPS) is a key enzyme in bacterial folate synthesis and the target of the sulfonamide class of antibacterials. Resistance and toxicities associated with sulfonamides have led to a decrease in their clinical use. Compounds that bind to the pterin binding site of DHPS, as opposed to the p-amino benzoic acid (pABA) binding site targeted by the sulfonamide agents, are anticipated to bypass sulfonamide resistance. To identify such inhibitors and map the pterin binding pocket, we have performed virtual screening, synthetic, and structural studies using Bacillus anthracis DHPS. Several compounds with inhibitory activity have been identified, and crystal structures have been determined that show how the compounds engage the pterin site. The structural studies identify the key binding elements and have been used to generate a structure-activity based pharmacophore map that will facilitate the development of the next generation of DHPS inhibitors which specifically target the pterin site.

  1. Structural Studies of Pterin-Based Inhibitors of Dihydropteroate Synthase

    PubMed Central

    Hevener, Kirk E.; Yun, Mi-Kyung; Qi, Jianjun; Kerr, Iain D.; Babaoglu, Kerim; Hurdle, Julian G.; Balakrishna, Kanya; White, Stephen W.; Lee, Richard E.

    2009-01-01

    Dihydropteroate synthase (DHPS) is a key enzyme in bacterial folate synthesis and the target of the sulfonamide class of antibacterials. Resistance and toxicities associated with sulfonamides have led to a decrease in their clinical use. Compounds that bind to the pterin binding site of DHPS, as opposed to the p-amino benzoic acid (pABA) binding site targeted by the sulfonamide agents, are anticipated to bypass sulfonamide resistance. To identify such inhibitors and map the pterin binding pocket, we have performed virtual screening, synthetic, and structural studies using Bacillus anthracis DHPS. Several compounds with inhibitory activity have been identified, and crystal structures have been determined that show how the compounds engage the pterin site. The structural studies identify the key binding elements and have been used to generate a structure-activity based pharmacophore map that will facilitate the development of the next generation of DHPS inhibitors which specifically target the pterin site. PMID:19899766

  2. Methodical Base of Experimental Studies of Collinear Multibody Decays

    NASA Astrophysics Data System (ADS)

    Kamanin, D. V.; Zhuchko, V. E.; Kondtatyev, N. A.; Alexandrov, A. A.; Alexandrova, I. A.; Kuznetsova, E. A.; Strekalovsky, A. O.; Strekalovsky, O. V.; Pyatkov, Yu. V.; Jacobs, N.; Malaza, V.; Mulgin, S. I.

    2013-06-01

    Our recent experiments dedicated to study of the CCT of 252Cf (sf) were carried out at the COMETA setup based on the mosaics of PIN diodes and special array of 3He filled neutron counters. Principal peculiarity of the experiment consists in measuring of the heavy ions masses in the frame of the TOF-E (time-of-flight vs. energy) method in the wide range of masses and energies and almost collinear recession of the decay partners. The methodical questions of such experiment are under discussion here.

  3. DENSITY-FUNCTIONAL STUDY OF Zr-BASED ACTINIDE ALLOYS

    SciTech Connect

    Landa, A; Soderlind, P; Turchi, P; Vitos, L; Ruban, A

    2008-06-26

    Density-functional formalism is applied to study the phase equilibria in the U-Zr system. The obtained ground-state properties of the {gamma} (bcc) and {delta} (C32) phases are in good agreement with experimental data. The decomposition curve for the {gamma}-based U-Zr solutions is calculated. We argue that stabilization of the {delta}-UZr{sub 2} phase relative to the {alpha}-Zr (hcp) structure is due to an increase of the Zr d-band occupancy that occurs when U is alloyed with Zr.

  4. Feasibility study of a microprocessor based oculometer system

    NASA Technical Reports Server (NTRS)

    Varanasi, M. R.

    1981-01-01

    The elimination of redundancy in data to maximize processing speed and minimize storage requirements were objectives in a feasibility study of a microprocessor based oculometer system that would be portable in size and flexible in use. The appropriate architectural design of the signal processor, improved optics, and the reduction of size, weight, and power to the system were investigated. A flow chart is presented showing the strategy of the design. The simulation for developing microroutines for the high speed algorithmic processor subsystem is discussed as well as the Karhunen-Loeve transform technique for data compression.

  5. Metabolite-based genome-wide association studies in plants.

    PubMed

    Luo, Jie

    2015-04-01

    The plant metabolome is the readout of plant physiological status and is regarded as the bridge between the genome and the phenome of plants. Unraveling the natural variation and the underlying genetic basis of plant metabolism has received increasing interest from plant biologists. Enabled by the recent advances in high-throughput profiling and genotyping technologies, metabolite-based genome-wide association study (mGWAS) has emerged as a powerful alternative forward genetics strategy to dissect the genetic and biochemical bases of metabolism in model and crop plants. In this review, recent progress and applications of mGWAS in understanding the genetic control of plant metabolism and in interactive functional genomics and metabolomics are presented. Further directions and perspectives of mGWAS in plants are also discussed. PMID:25637954

  6. A case study in evidence-based wound management.

    PubMed

    Patten, J

    On the first of July 1998, Frank Dobson, the then Secretary of State for Health, revealed the consultation document 'A First Class Service' (Department of Health (DoH), 1998). This article describes a wound management case study which showed how a first class service was provided for a patient with very severe pressure ulcers and complex medical problems. A multiprofessional approach to her complex and challenging problems was maintained. Evidence-based guidelines for the prevention and management of pressure damage were followed, supported by modern researched-based wound management and pressure relief. In addition, risk management strategies were observed, and provided the basis for planning and evaluating her individualized care. PMID:11235289

  7. Cutoff Designs for Community-Based Intervention Studies

    PubMed Central

    Pennell, Michael L.; Hade, Erinn M.; Murray, David M.; Rhoda, Dale A.

    2011-01-01

    Summary Public health interventions are often designed to target communities defined either geographically (e.g., cities, counties) or socially (e.g., schools or workplaces). The group randomized trial (GRT) is regarded as the gold standard for evaluating these interventions. However, community leaders may object to randomization as some groups may be denied a potentially beneficial intervention. Under a regression discontinuity design (RDD), individuals may be assigned to treatment based on the levels of a pretest measure, thereby allowing those most in need of the treatment to receive it. In this article, we consider analysis, power, and sample size issues in applying the RDD and related cutoff designs in community-based intervention studies. We examine the power of these designs as a function of intraclass correlation, number of groups, and number of members per group and compare results to the traditional GRT. PMID:21500240

  8. Neural bases for anticipation skill in soccer: an FMRI study.

    PubMed

    Bishop, Daniel T; Wright, Michael J; Jackson, Robin C; Abernethy, Bruce

    2013-02-01

    The aim of this study was to examine the neural bases for perceptual-cognitive superiority in a soccer anticipation task using functional magnetic resonance imaging (fMRI). Thirty-nine participants lay in an MRI scanner while performing a video-based task in which they predicted an oncoming opponent's movements. Video clips were occluded at four time points, and participants were grouped according to in-task performance. Early occlusion reduced prediction accuracy significantly for all participants, as did the opponent's execution of a deceptive maneuver; however, high-skill participants were significantly more accurate than their low-skill counterparts under deceptive conditions. This perceptual-cognitive superiority was associated with greater activation of cortical and subcortical structures involved in executive function and oculomotor control. The contributions of the present findings to an existing neural model of anticipation in sport are highlighted. PMID:23404883

  9. Studies of oceanic tectonics based on GEOS-3 satellite altimetry

    NASA Technical Reports Server (NTRS)

    Poehls, K. A.; Kaula, W. M.; Schubert, G.; Sandwell, D.

    1979-01-01

    Using statistical analysis, geoidal admittance (the relationship between the ocean geoid and seafloor topography) obtained from GEOS-3 altimetry was compared to various model admittances. Analysis of several altimetry tracks in the Pacific Ocean demonstrated a low coherence between altimetry and seafloor topography except where the track crosses active or recent tectonic features. However, global statistical studies using the much larger data base of all available gravimetry showed a positive correlation of oceanic gravity with topography. The oceanic lithosphere was modeled by simultaneously inverting surface wave dispersion, topography, and gravity data. Efforts to incorporate geoid data into the inversion showed that the base of the subchannel can be better resolved with geoid rather than gravity data. Thermomechanical models of seafloor spreading taking into account differing plate velocities, heat source distributions, and rock rheologies were discussed.

  10. A simulation based case study for control of DSTATCOM.

    PubMed

    Kumar, Pradeep; Kumar, Niranjan; Akella, A K

    2014-05-01

    This paper presents a distribution static compensator (DSTATCOM) for power quality improvements in terms of harmonics and power factor correction in a three-phase four-wire distribution system. The DSTATCOM is implemented with PWM current controlled six-leg voltage source converter (VSC) and the switching patterns are generated through a novel synchronous reference frame controller (SRFC). The insulated gate bipolar transistor (IGBT) based VSC is supported by a capacitor and is controlled for the required compensation of the load current. The DSTATCOM is connected to the power system feeding nonlinear loads. Nonlinear loads include either current-source type or voltage-source type. Harmonic spectrum of the source current is compared in between without DSTATCOM and with DSTATCOM by considering both types of nonlinear loads. The SRFC based DSTATCOM system is validated through extensive simulation for diode-rectifier and unbalanced R-L loads with a case study. PMID:24656282

  11. A community-based study of asthenopia in computer operators

    PubMed Central

    Choudhary, Sushilkumar; Doshi, Vikas G

    2008-01-01

    Context: There is growing body of evidence that use of computers can adversely affect the visual health. Considering the rising number of computer users in India, computer-related asthenopia might take an epidemic form. In view of that, this study was undertaken to find out the magnitude of asthenopia in computer operators and its relationship with various personal and workplace factors. Aims: To study the prevalence of asthenopia among computer operators and its association with various epidemiological factors. Settings and Design: Community-based cross-sectional study of 419 subjects who work on computer for varying period of time. Materials and Methods: Four hundred forty computer operators working in different institutes were selected randomly. Twenty-one did not participate in the study, making the nonresponse rate 4.8%. Rest of the subjects (n = 419) were asked to fill a pre-tested questionnaire, after obtaining their verbal consent. Other relevant information was obtained by personal interview and inspection of workstation. Statistical Analysis Used: Simple proportions and Chi-square test. Results: Among the 419 subjects studied, 194 (46.3%) suffered from asthenopia during or after work on computer. Marginally higher proportion of asthenopia was noted in females compared to males. Occurrence of asthenopia was significantly associated with age of starting use of computer, presence of refractive error, viewing distance, level of top of the computer screen with respect to eyes, use of antiglare screen and adjustment of contrast and brightness of monitor screen. Conclusions: Prevalence of asthenopia was noted to be quite high among computer operators, particularly in those who started its use at an early age. Individual as well as work-related factors were found to be predictive of asthenopia. PMID:18158404

  12. Data base dictionary for the Oak Ridge Reservation Hydrology and Geology Study Groundwater Data Base

    SciTech Connect

    Thompson, B.K.

    1993-04-01

    The Oak Ridge Reservation Hydrology and Geology Study (ORRHAGS) Groundwater Data Base has been compiled to consolidate groundwater data from the three US Department of Energy facilities located on the Oak Ridge Reservation: the Oak Ridge K-25 Site, the Oak Ridge National Laboratory, and the Oak Ridge Y-12 Plant. Each of these facilities maintains its own groundwater and well construction data bases. Data were extracted from the existing data bases, converted to a consistent format, and integrated into the ORRHAGS Groundwater Data Base structures. This data base dictionary describes the data contained in the ORRHAGS Groundwater Data Base and contains information on data base structure, conventions, contents, and use.

  13. Feature-based MRI data fusion for cardiac arrhythmia studies.

    PubMed

    Magtibay, Karl; Beheshti, Mohammadali; Foomany, Farbod Hosseyndoust; Massé, Stéphane; Lai, Patrick F H; Zamiri, Nima; Asta, John; Nanthakumar, Kumaraswamy; Jaffray, David; Krishnan, Sridhar; Umapathy, Karthikeyan

    2016-05-01

    Current practices in studying cardiac arrhythmias primarily use electrical or optical surface recordings of a heart, spatially limited transmural recordings, and mathematical models. However, given that such arrhythmias occur on a 3D myocardial tissue, information obtained from such practices lack in dimension, completeness, and are sometimes prone to oversimplification. The combination of complementary Magnetic-Resonance Imaging (MRI)-based techniques such as Current Density Imaging (CDI) and Diffusion Tensor Imaging (DTI) could provide more depth to current practices in assessing the cardiac arrhythmia dynamics in entire cross sections of myocardium. In this work, we present an approach utilizing feature-based data fusion methods to demonstrate that complimentary information obtained from electrical current distribution and structural properties within a heart could be quantified and enhanced. Twelve (12) pairs of CDI and DTI image data sets were gathered from porcine hearts perfused through a Langendorff setup. Images were fused together using feature-based data fusion techniques such as Joint Independent Component Analysis (jICA), Canonical Correlation Analysis (CCA), and their combination (CCA+jICA). The results suggest that the complimentary information of cardiac states from CDI and DTI are enhanced and are better classified with the use of data fusion methods. For each data set, an increase in mean correlations of fused images were observed with 38% increase from CCA+jICA compared to the original images while mean mutual information of the fused images from jICA and CCA+jICA increased by approximately three-fold. We conclude that MRI-based techniques present potential viable tools in furthering studies for cardiac arrhythmias especially Ventricular Fibrillation. PMID:26970857

  14. Study on Cloud Security Based on Trust Spanning Tree Protocol

    NASA Astrophysics Data System (ADS)

    Lai, Yingxu; Liu, Zenghui; Pan, Qiuyue; Liu, Jing

    2015-09-01

    Attacks executed on Spanning Tree Protocol (STP) expose the weakness of link layer protocols and put the higher layers in jeopardy. Although the problems have been studied for many years and various solutions have been proposed, many security issues remain. To enhance the security and credibility of layer-2 network, we propose a trust-based spanning tree protocol aiming at achieving a higher credibility of LAN switch with a simple and lightweight authentication mechanism. If correctly implemented in each trusted switch, the authentication of trust-based STP can guarantee the credibility of topology information that is announced to other switch in the LAN. To verify the enforcement of the trusted protocol, we present a new trust evaluation method of the STP using a specification-based state model. We implement a prototype of trust-based STP to investigate its practicality. Experiment shows that the trusted protocol can achieve security goals and effectively avoid STP attacks with a lower computation overhead and good convergence performance.

  15. Clinical TVA-based studies: a general review

    PubMed Central

    Habekost, Thomas

    2015-01-01

    In combination with whole report and partial report tasks, the theory of visual attention (TVA) can be used to estimate individual differences in five basic attentional parameters: the visual processing speed, the storage capacity of visual short-term memory, the perceptual threshold, the efficiency of top–down selectivity, and the spatial bias of attentional weighting. TVA-based assessment has been used in about 30 studies to investigate attentional deficits in a range of neurological and psychiatric conditions: (a) neglect and simultanagnosia, (b) reading disturbances, (c) aging and neurodegenerative diseases, and most recently (d) neurodevelopmental disorders. The article introduces TVA based assessment, discusses its methodology and psychometric properties, and reviews the progress made in each of the four research fields. The empirical results demonstrate the general usefulness of TVA-based assessment for many types of clinical neuropsychological research. The method’s most important qualities are cognitive specificity and theoretical grounding, but it is also characterized by good reliability and sensitivity to minor deficits. The review concludes by pointing to promising new areas for clinical TVA-based research. PMID:25852607

  16. Preclinical Studies for Induced Pluripotent Stem Cell-based Therapeutics*

    PubMed Central

    Harding, John; Mirochnitchenko, Oleg

    2014-01-01

    Induced pluripotent stem cells (iPSCs) and their differentiated derivatives can potentially be applied to cell-based therapy for human diseases. The properties of iPSCs are being studied intensively both to understand the basic biology of pluripotency and cellular differentiation and to solve problems associated with therapeutic applications. Examples of specific preclinical applications summarized briefly in this minireview include the use of iPSCs to treat diseases of the liver, nervous system, eye, and heart and metabolic conditions such as diabetes. Early stage studies illustrate the potential of iPSC-derived cells and have identified several challenges that must be addressed before moving to clinical trials. These include rigorous quality control and efficient production of required cell populations, improvement of cell survival and engraftment, and development of technologies to monitor transplanted cell behavior for extended periods of time. Problems related to immune rejection, genetic instability, and tumorigenicity must be solved. Testing the efficacy of iPSC-based therapies requires further improvement of animal models precisely recapitulating human disease conditions. PMID:24362021

  17. Endometrial cancer and antidepressants: A nationwide population-based study.

    PubMed

    Lin, Chiao-Fan; Chan, Hsiang-Lin; Hsieh, Yi-Hsuan; Liang, Hsin-Yi; Chiu, Wei-Che; Huang, Kuo-You; Lee, Yena; McIntyre, Roger S; Chen, Vincent Chin-Hung

    2016-07-01

    To our knowledge, the association between antidepressant exposure and endometrial cancer has not been previously explored. Herein, we aim to investigate the association between antidepressant prescription, including novel antidepressants, and the risk for endometrial cancer in a population-based study.Data for the analysis were derived from National Health Insurance Research Database. We identified 8392 cases with a diagnosis of endometrial cancer and 82,432 matched controls. A conditional logistic regression model was used, with adjusting for potentially confounding variables (e.g., comorbid psychiatric diseases, comorbid physical diseases, and other medications). Risk for endometrial cancer in the population-based study sample was categorized by, and assessed as a function of, antidepressant prescription and cumulative dosage.We report no association between endometrial cancer incidence and antidepressant prescription, including those prescribed either selective serotonin reuptake inhibitors (adjusted odds ratio [OR] = 0.98; 95% confidence interval [CI], 0.84-1.15) or serotonin norepinephrine reuptake inhibitors (adjusted OR = 1.14; 95% CI, 0.76-1.71). We also did not identify an association between higher cumulative doses of antidepressant prescription and endometrial cancer.There was no association between antidepressant prescription and endometrial cancer. PMID:27442640

  18. A study of trends and techniques for space base electronics

    NASA Technical Reports Server (NTRS)

    Trotter, J. D.; Wade, T. E.; Gassaway, J. D.; Mahmood, Q.

    1978-01-01

    A sputtering system was developed to deposit aluminum and aluminum alloys by the dc sputtering technique. This system is designed for a high level of cleanliness and for monitoring the deposition parameters during film preparation. This system is now ready for studying the deposition and annealing parameters upon double-level metal preparation. A technique recently applied for semiconductor analysis, the finite element method, was studied for use in the computer modeling of two dimensional MOS transistor structures. It was concluded that the method has not been sufficiently well developed for confident use at this time. An algorithm was developed for confident use at this time. An algorithm was developed for implementing a computer study which is based upon the finite difference method. The program which was developed was modified and used to calculate redistribution data for boron and phosphorous which had been predeposited by ion implantation with range and straggle conditions. Data were generated for 111 oriented SOS films with redistribution in N2, dry O2 and steam ambients.

  19. Ground based studies of thermocapillary flows in levitated drops

    NASA Technical Reports Server (NTRS)

    Sadhal, Satwindar Singh; Trinh, Eugene H.

    1994-01-01

    Analytical studies along with ground-based experiments are presently being carried out in connection with thermocapillary phenomena associated with drops and bubbles in a containerless environment. The effort here focuses on the thermal and the fluid phenomena associated with the local heating of acoustically levitated drops, both at 1-g and at low-g. In particular, the Marangoni effect on drops under conditions of local spot-heating and other types of heating are being studied. With the experiments conducted to date, fairly stable acoustic levitation of drops has been achieved and successful flow visualization by light scattering from smoke particles has been carried out. The results include situations with and without heating. As a preliminary qualitative interpretation of these experimental results, we consider the external flow pattern as a superposition of three discrete circulation cells operating on different spatial scales. The observations of the flow fields also indicate the existence of a steady state torque induced by the streaming flows. The theoretical studies have been concentrated on the analysis of streaming flows in a gaseous medium with the presence of a spherical particle undergoing periodic heating. A matched asymptotic analysis was carried out for small parameters derived from approximations in the high frequency range. The heating frequency being 'in tune' with the acoustic frequency results in a nonzero time-averaged thermal field. This leads to a steady heat flow across the equatorial plane of the sphere.

  20. Ground Based Studies of Thermocapillary Flows in Levitated Drops

    NASA Technical Reports Server (NTRS)

    Sadhal, Satwindar Singh; Trinh, Eugene H.

    1996-01-01

    Ground-based experiments together with analytical studies are presently being conducted for levitated drops. Both acoustic and electrostatic techniques are being employed to achieve levitation of drops in a gaseous environment. The scientific effort is principally on the thermal and the fluid phenomena associated with the local heating of levitated drops, both at 1-g and at low-g. In particular, the thermocapillary flow associated with local spot heating is being studied. Fairly stable acoustic levitation of drops has been achieved with some exceptions when random rotational motion of the drop persists. The flow visualization has been carried out by light scattering from smoke particles for the exterior flow and fluorescent tracer particles in the drop. The results indicate a lack of axial symmetry in the internal flow even though the apparatus and the heating are symmetric. The theoretical studies for the past year have included fundamental analyses of acoustically levitated spherical drops. The flow associated with a particle near the velocity antinode is being investigated by the singular perturbation technique. As a first step towards understanding the effect of the particle displacement from the antinode, the flow field about the node has been calculated for the first time. The effect of the acoustic field on the interior of a liquid drop has also been investigated. The results predict that the internal flow field is very weak.

  1. Synthesis, base pairing and structure studies of geranylated RNA.

    PubMed

    Wang, Rui; Vangaveti, Sweta; Ranganathan, Srivathsan V; Basanta-Sanchez, Maria; Haruehanroengra, Phensinee; Chen, Alan; Sheng, Jia

    2016-07-27

    Natural RNAs utilize extensive chemical modifications to diversify their structures and functions. 2-Thiouridine geranylation is a special hydrophobic tRNA modification that has been discovered very recently in several bacteria, such as Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa and Salmonella Typhimurium The geranylated residues are located in the first anticodon position of tRNAs specific for lysine, glutamine and glutamic acid. This big hydrophobic terpene functional group affects the codon recognition patterns and reduces frameshifting errors during translation. We aimed to systematically study the structure, function and biosynthesis mechanism of this geranylation pathway, as well as answer the question of why nature uses such a hydrophobic modification in hydrophilic RNA systems. Recently, we have synthesized the deoxy-analog of S-geranyluridine and showed the geranylated T-G pair is much stronger than the geranylated T-A pair and other mismatched pairs in the B-form DNA duplex context, which is consistent with the observation that the geranylated tRNA(Glu) UUC recognizes GAG more efficiently than GAA. In this manuscript we report the synthesis and base pairing specificity studies of geranylated RNA oligos. We also report extensive molecular simulation studies to explore the structural features of the geranyl group in the context of A-form RNA and its effect on codon-anticodon interaction during ribosome binding. PMID:27307604

  2. Synthesis, characterization and antimicrobial studies of Schiff base complexes

    NASA Astrophysics Data System (ADS)

    Zafar, Hina; Ahmad, Anis; Khan, Asad U.; Khan, Tahir Ali

    2015-10-01

    The Schiff base complexes, MLCl2 [M = Fe(II), Co(II), Ni(II), Cu(II) and Zn(II)] have been synthesized by the template reaction of respective metal ions with 2-acetylpyrrole and 1,3-diaminopropane in 1:2:1 M ratio. The complexes have been characterized by elemental analyses, ESI - mass, NMR (1H and 13C), IR, XRD, electronic and EPR spectral studies, magnetic susceptibility and molar conductance measurements. These studies show that all the complexes have octahedral arrangement around the metal ions. The molar conductance measurements of all the complexes in DMSO indicate their non-electrolytic nature. The complexes were screened for their antibacterial activity in vitro against Gram-positive (Streptococcus pyogenes) and Gram-negative (Klebsiella pneumoniae) bacteria. Among the metal complexes studied the copper complex [CuLCl2], showed highest antibacterial activity nearly equal to standard drug ciprofloxacin. Other complexes also showed considerable antibacterial activity. The relative order of activity against S. Pyogenes is as Cu(II) > Zn(II) > Co(II) = Fe(II) > Ni(II) and with K. Pneumonia is as Cu(II) > Co(II) > Zn(II) > Fe(II) > Ni(II).

  3. Study of Mare Moscoviense based on orbital NIR hyperspectral data

    NASA Astrophysics Data System (ADS)

    Bhatt, Megha; Wöhler, Christian; Bhardwaj, Anil; Mall, Urs; Grumpe, Arne; Rommel, Daniela

    2016-07-01

    The Moscoviense basin is an important lunar farside impact basin. Previous studies of this region suggest compositional variations across the mare basalts, and significant positive gravity anomaly within the basin [1, 2]. In the highlands immediately west of the mare regions inside the Moscoviense basin, unusual spectral signatures indicating small deposits of orthopyroxene, olivine and spinel have been detected [3]. A detailed study of the Moscoviense basin thus allows for an examination of lunar farside highland materials and mare basalts of varying composition and age, providing insights into the lunar mantle composition and magmatic history. We present a geological study of Mare Moscoviense based on near-infrared high-resolution hyperspectral data obtained by the Moon Mineralogy Mapper (M3) [4] and the near-infrared spectrometer, SIR-2 [5]. An M3 reflectance mosaic of the region has been prepared after applying corrections for thermal emission and topography. Two SIR-2 orbits recorded from 100 km spacecraft altitude have also been used for mineralogical study of the region. Elemental abundance maps of Ti, Ca and Mg as well as a petrologic map have been prepared based on the method described in [6]. Furthermore, we utilized the three different algorithms described in [6, 7, 8] for estimating Fe abundances using the 1-µm and/or 2-µm absorption band parameters. This comparative study aims to identify and map the major morphological and compositional units within the Mare Moscoviense region. References: [1] Gillis et al. (1998) Ph.D. thesis, 248 pp., Rice Univ., Houston, Texas; [2] Kramer et al. (2008) JGR 113, E01002, doi:10.1029/2006JE002860; [3] Pieters et al. (2011) JGR 116, E00G08, doi:10.1029/2010JE003727; [4] Pieters C. M. et al. (2009) Current Science 96, 500-505; [5] Mall, U. et al. (2009) Current Science 96, 506-511; [6] Wöhler C. et al. (2014) Icarus 235, 86-122; [7] Lucey P. G. et al. (2000) JGR 105, 20297-20306; [8] Bhatt M. et al. (2015) Icarus 248

  4. Young adults' trajectories of Ecstasy use: a population based study.

    PubMed

    Smirnov, Andrew; Najman, Jake M; Hayatbakhsh, Reza; Plotnikova, Maria; Wells, Helene; Legosz, Margot; Kemp, Robert

    2013-11-01

    Young adults' Ecstasy use trajectories have important implications for individual and population-level consequences of Ecstasy use, but little relevant research has been conducted. This study prospectively examines Ecstasy trajectories in a population-based sample. Data are from the Natural History Study of Drug Use, a retrospective/prospective cohort study conducted in Australia. Population screening identified a probability sample of Ecstasy users aged 19-23 years. Complete data for 30 months of follow-up, comprising 4 time intervals, were available for 297 participants (88.4% of sample). Trajectories were derived using cluster analysis based on recent Ecstasy use at each interval. Trajectory predictors were examined using a generalized ordered logit model and included Ecstasy dependence (World Mental Health Composite International Diagnostic Instrument), psychological distress (Hospital Anxiety Depression Scale), aggression (Young Adult Self Report) and contextual factors (e.g. attendance at electronic/dance music events). Three Ecstasy trajectories were identified (low, intermediate and high use). At its peak, the high-use trajectory involved 1-2 days Ecstasy use per week. Decreasing frequency of use was observed for intermediate and high-use trajectories from 12 months, independently of market factors. Intermediate and high-use trajectory membership was predicted by past Ecstasy consumption (>70 pills) and attendance at electronic/dance music events. High-use trajectory members were unlikely to have used Ecstasy for more than 3 years and tended to report consistently positive subjective effects at baseline. Given the social context and temporal course of Ecstasy use, Ecstasy trajectories might be better understood in terms of instrumental rather than addictive drug use patterns. PMID:23899430

  5. A Study on the Efficacy of Project-Based Learning Approach on Social Studies Education: Conceptual Achievement and Academic Motivation

    ERIC Educational Resources Information Center

    Ilter, Ilhan

    2014-01-01

    In this research, an experimental study was carried out in social studies 4th grade students to develop students' conceptual achievement and motivation to succeed academically. The study aims to investigate the effectiveness of project-based learning (PBL) in social studies. A quasi-experimental research design (pre- and posttest) was used in…

  6. Recruitment for a community-based study of early pregnancy: the Right From The Start study.

    PubMed

    Promislow, Joanne H E; Makarushka, Christina M; Gorman, Jessica R; Howards, Penelope P; Savitz, David A; Hartmann, Katherine E

    2004-03-01

    Despite the high incidence of spontaneous abortion, little is known about its causes, in part because of the challenge of assembling a large cohort of women in early pregnancy for prospective study. We describe the effectiveness of recruitment strategies used in Right From The Start (RFTS), a prospective, community-based study of spontaneous abortion. Between December 2000 and September 2002, 803 pregnant women enrolled in RFTS, 103 of whom were recruited while trying to conceive. The mean gestational age at enrollment was 52 days, with 25% of the cohort enrolling before 6 completed weeks' gestation. Participants recruited directly from the community typically enrolled earlier in their pregnancies (mean of 44 days) and accounted for 24% of the total cohort and 83% of all participants who were recruited while trying to conceive. Posting brochures in drug stores and targeted mailings to new homeowners were the most effective community recruitment strategies. Recruitment at private and public prenatal care sites accounted for 57% and 19% of the participants respectively. Recruitment from public clinics required direct contact by RFTS staff and yielded women who enrolled at later gestational ages (mean of 58 days), but was valuable for inclusion of minorities and lower income women with less favourable health behaviours. Although intensive, diverse efforts were required, when recruitment efforts were maximised, we successfully recruited over 10% of the estimated number of pregnant women in the community. PMID:14996255

  7. Instructor Based Training Versus Computer Based Training--A Comparative Study

    ERIC Educational Resources Information Center

    Malmskold, Lennart; Ortengren, Roland; Carlson, Blair E.; Nylen, Per

    2007-01-01

    This article describes two studies conducted to compare assembly performance and learning rate between computer based training and traditional training of skilled assembly operators. The studies were performed with pre-series production parts from a car cockpit and they were integrated as part of the overall training activities during a new…

  8. Sitewide feasibility study Eielson Air Force Base, Alaska

    SciTech Connect

    Last, G.V.; Lanigan, D.C.; Josephson, G.B.; Bagaasen, L.M.

    1995-09-01

    The Sitewide Feasibility Study (FS) is required under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), the National Contingency Plan (NCP), and the Federal Facility Agreement (FFA) for Eielson Air Force Base (AFB). It is based on findings presented in the Sitewide Remedial Investigation (RI) Report (USAF 1995a), and the Sitewide Baseline Risk Assessment (BLRA) Report (USAF 1995b). Under the FFA, 64 potential source areas were placed in one of six operable units, based on similar contaminant and environmental characteristics, or were included for evaluation under a Source Evaluation Report (SER). The sitewide RI was directed at contamination that was not confined to an operable unit (OU) or SER source area. The objectives of the sitewide RI were to: Provide information about site characteristics to support individual OU RI/FS efforts and the sitewide RI/FS, including site hydrogeology and determination of background soil and groundwater characteristics; identify and characterize contamination that is not confined or attributable to a specific source area through sitewide monitoring of groundwater and surface water; evaluate cumulative risks to human health and the environment from contamination on a sitewide basis; and provide a mechanism for continued cohesive sitewide monitoring.

  9. Feasibility study of a soil-based rubberized CLSM.

    PubMed

    Wu, Jason Y; Tsai, Mufan

    2009-02-01

    The development of beneficial uses of recycled scrap tires is always in great demand around the world. The disposal of on-site surplus excavated soil and the production of standard engineering aggregates have also been facing increasing environmental and ecological challenges in congested islands, such as Taiwan. This paper presents an experimental study using recycled crumb rubber and native silty sand to produce a lightweight, soil-based, rubberized controlled low strength material (CLSM) for a bridge approach repair. To assess the technical feasibility of this material, the effects of weight ratios of cement-to-water (C/W) and water-to-solid (W/S), and of rubber content on the engineering properties for different mixtures were investigated. The presented test results include flowability, unit weight, strength, settlement potential, and bearing capacity. Based on the findings, we conclude that a soil-based rubberized CLSM with 40% sand by weight and an optimal design ratio of 0.7 for C/W and 0.35 for W/S can be used for the proposed bridge approach repair. Such a mixture has demonstrated acceptable flowability, strength, and bearing capacity. Its lower unit weight, negligible compressibility, and hydrocollapse potential also help ensure that detrimental settlement is unlikely to occur. The results illustrate a novel scheme of CLSM production, and suggest a beneficial alternative for the reduction of scrap tires as well as conservation of resources and environment. PMID:18678479

  10. Synthesis and study of novel silicon-based unsaturated polymers

    SciTech Connect

    Lin, J.

    1995-06-19

    Novel unsaturated polymers have been synthesized and studied as precursors to silicon carbide and third order nonlinear optical materials. X ray structures were obtained. Kinetic and mechanistic studies of the unique thermal isomerization of dimethylenedisilacyclobutane to a carbene were conducted.

  11. Computational study of dislocation based mechanisms in FCC materials

    NASA Astrophysics Data System (ADS)

    Yellakara, Ranga Nikhil

    Understanding the relationships between microstructures and properties of materials is a key to developing new materials with more suitable qualities or employing the appropriate materials in special uses. In the present world of material research, the main focus is on microstructural control to cost-effectively enhance properties and meet performance specifications. This present work is directed towards improving the fundamental understanding of the microscale deformation mechanisms and mechanical behavior of metallic alloys, particularly focusing on face centered cubic (FCC) structured metals through a unique computational methodology called three-dimensional dislocation dynamics (3D-DD). In these simulations, the equations of motion for dislocations are mathematically solved to determine the evolution and interaction of dislocations. Microstructure details and stress-strain curves are a direct observation in the simulation and can be used to validate experimental results. The effect of initial dislocation microstructure on the yield strength has been studied. It has been shown that dislocation density based crystal plasticity formulations only work when dislocation densities/numbers are sufficiently large so that a statistically accurate description of the microstructure can be obtainable. The evolution of the flow stress for grain sizes ranging from 0.5 to 10 mum under uniaxial tension was simulated using an improvised model by integrating dislocation pile-up mechanism at grain boundaries has been performed. This study showed that for a same initial dislocation density, the Hall--Petch relationship holds well at small grain sizes (0.5--2 mum), beyond which the yield strength remains constant as the grain size increases. Various dislocation-particle interaction mechanisms have been introduced and investigations were made on their effect on the uniaxial tensile properties. These studies suggested that increase in particle volume fraction and decrease in particle

  12. Treatability study of pesticide-based industrial wastewater.

    PubMed

    Shah, Kinnari; Chauhan, L I; Galgale, A D

    2012-10-01

    This paper finds out appropriate treatment methods for wastewater of an Organophosphorus viz, chloropyrifos pesticide manufacturing industry. The characterization of wastewater generated during trial production of chloropyrifos was carried out. Based on the characterization of wastewater, various treatability studies were conducted. The most desirable results were obtained with treatment scheme employing acidification, chlorination with NaOCl, suspended growth biological treatment, chemical precipitation for phosphorous removal and activated carbon treatment. Acidification of wastewater helps in by-product recovery as well as reduction in COD upto 36.26%. Chlorination followed by biological treatment was found to be effective to reduce the COD level by 62.06%. To comply with permissible limits prescribed by Effluent Channel Project Ltd.(ECPL)* and Gujarat Pollution Control Board (GPCB) for discharge of industrial effluent into channel, further treatment in the form of chemical precipitation (for phosphorous removal) and granular activated carbon is suggested. PMID:25151721

  13. Study of nanocomposites based on iron oxides and pectin

    NASA Astrophysics Data System (ADS)

    Chistyakova, Nataliya I.; Shapkin, Alexey A.; Sirazhdinov, Ruslan R.; Gubaidulina, Tatiana V.; Kiseleva, Tatiana Yu.; Kazakov, Alexander P.; Rusakov, Vyacheslav S.

    2014-10-01

    Mössbauer and X-ray diffraction study of nanocomposites based on iron oxides and pectin (PC) was carried out involving magnetization measurements. The concentrations of PC in nanocomposites varied from 0 to 10%. Mössbauer investigations of nanocomposites were carried out in the temperature range from 5 to 300 K. Many-state superparamagnetic relaxation model was used for spectra fitting. The magnetization, M(T,H), was measured in the temperature interval of 80-300 K and magnetic field up to 10 kOe. Formation of the "iron-polymer" interface was not observed. Particle sizes were estimated using the Mössbauer and X-ray powder diffraction data.

  14. Atomic softness-based QSAR study of testosterone

    NASA Astrophysics Data System (ADS)

    Srivastava, H. K.; Pasha, F. A.; Singh, P. P.

    Ionization potential of an atom in a molecule, electron affinity of an atom in a molecule, and quantum chemical descriptor atomic softness values En‡-based quantitative structure-activity relationship (QSAR) study of testosterone derivatives have been done with the help of PM3 calculations on WinMOPAC 7.21 software. The 3D modeling and geometry optimization of all the compounds have been done with the help of PCMODEL software. The biological activities of testosterone derivatives have been taken from literature. The predicted values of biological activity with the help of multiple linear regression (MLR) analysis is very close to observed biological activity. The cross-validation coefficient and correlation coefficient also indicate that the QSAR model is valuable. Regression analysis shows a very good relationship with biological activity and En‡ values. With the help of these values, prediction of the biological activity of any unknown compound is possible.

  15. Behavioral Modeling Based on Probabilistic Finite Automata: An Empirical Study.

    PubMed

    Tîrnăucă, Cristina; Montaña, José L; Ontañón, Santiago; González, Avelino J; Pardo, Luis M

    2016-01-01

    Imagine an agent that performs tasks according to different strategies. The goal of Behavioral Recognition (BR) is to identify which of the available strategies is the one being used by the agent, by simply observing the agent's actions and the environmental conditions during a certain period of time. The goal of Behavioral Cloning (BC) is more ambitious. In this last case, the learner must be able to build a model of the behavior of the agent. In both settings, the only assumption is that the learner has access to a training set that contains instances of observed behavioral traces for each available strategy. This paper studies a machine learning approach based on Probabilistic Finite Automata (PFAs), capable of achieving both the recognition and cloning tasks. We evaluate the performance of PFAs in the context of a simulated learning environment (in this case, a virtual Roomba vacuum cleaner robot), and compare it with a collection of other machine learning approaches. PMID:27347956

  16. Study of nanocomposites based on iron oxides and pectin

    SciTech Connect

    Chistyakova, Nataliya I. Shapkin, Alexey A. Sirazhdinov, Ruslan R. Gubaidulina, Tatiana V. Kiseleva, Tatiana Yu. Kazakov, Alexander P. Rusakov, Vyacheslav S.

    2014-10-27

    Mössbauer and X-ray diffraction study of nanocomposites based on iron oxides and pectin (PC) was carried out involving magnetization measurements. The concentrations of PC in nanocomposites varied from 0 to 10%. Mössbauer investigations of nanocomposites were carried out in the temperature range from 5 to 300 K. Many-state superparamagnetic relaxation model was used for spectra fitting. The magnetization, M(T,H), was measured in the temperature interval of 80-300 K and magnetic field up to 10 kOe. Formation of the 'iron-polymer' interface was not observed. Particle sizes were estimated using the Mössbauer and X-ray powder diffraction data.

  17. Study of Flapping Flight Using Discrete Vortex Method Based Simulations

    NASA Astrophysics Data System (ADS)

    Devranjan, S.; Jalikop, Shreyas V.; Sreenivas, K. R.

    2013-12-01

    In recent times, research in the area of flapping flight has attracted renewed interest with an endeavor to use this mechanism in Micro Air vehicles (MAVs). For a sustained and high-endurance flight, having larger payload carrying capacity we need to identify a simple and efficient flapping-kinematics. In this paper, we have used flow visualizations and Discrete Vortex Method (DVM) based simulations for the study of flapping flight. Our results highlight that simple flapping kinematics with down-stroke period (tD) shorter than the upstroke period (tU) would produce a sustained lift. We have identified optimal asymmetry ratio (Ar = tD/tU), for which flapping-wings will produce maximum lift and find that introducing optimal wing flexibility will further enhances the lift.

  18. Predictors of Childhood Anxiety: A Population-Based Cohort Study

    PubMed Central

    2015-01-01

    Background Few studies have explored predictors of early childhood anxiety. Objective To determine the prenatal, postnatal, and early life predictors of childhood anxiety by age 5. Methods Population-based, provincial administrative data (N = 19,316) from Manitoba, Canada were used to determine the association between demographic, obstetrical, psychosocial, medical, behavioral, and infant factors on childhood anxiety. Results Risk factors for childhood anxiety by age 5 included maternal psychological distress from birth to 12 months and 13 months to 5 years post-delivery and an infant 5-minute Apgar score of ≤7. Factors associated with decreased risk included maternal age < 20 years, multiparity, and preterm birth. Conclusion Identifying predictors of childhood anxiety is a key step to early detection and prevention. Maternal psychological distress is an early, modifiable risk factor. Future research should aim to disentangle early life influences on childhood anxiety occurring in the prenatal, postnatal, and early childhood periods. PMID:26158268

  19. A Study of Central Auction Based Wholesale Electricity Markets

    NASA Astrophysics Data System (ADS)

    Ceppi, Sofia; Gatti, Nicola

    The deregulation of electricity markets produced significant economic benefits, reducing prices to customers and opening several opportunities for new actors, e.g., new generators and distributors. A prominent scientific and technological challenge is the automation of such markets. In particular, we focus our attention on wholesale electricity markets based on a central auction. In these markets, generators sell electricity by means of a central auction to a public authority. Instead, the distribution of electricity to customers takes part in retail markets. The main works presented in the literature model wholesale markets as oligopolies, neglecting thus the specific auction mechanism. In this paper, we enrich these models by introducing an auction mechanism shaped on that used in the Italian wholesale electricity market, we solve the winner determination problem, and we preliminarily study the problem of searching for equilibria.

  20. A population-based study of birth defects in Malaysia.

    PubMed

    Thong, M K; Ho, J J; Khatijah, N N

    2005-01-01

    Birth defects are one of the leading causes of paediatric disability and mortality in developed and developing countries. Data on birth defects from population-based studies originating from developing countries are lacking. One of the objectives of this study was to determine the epidemiology of major birth defects in births during the perinatal period in Kinta district, Perak, Malaysia over a 14-month period, using a population-based birth defect register. There were 253 babies with major birth defects in 17,720 births, giving an incidence of 14.3/1000 births, a birth prevalence of 1 in 70. There were 80 babies with multiple birth defects and 173 with isolated birth defects. The exact syndromic diagnosis of the babies with multiple birth defects could not be identified in 18 (22.5%) babies. The main organ systems involved in the isolated birth defects were cardiovascular (13.8%), cleft lip and palate (11.9%), clubfeet (9.1%), central nervous system (CNS) (including neural tube defects) (7.9%), musculoskeletal (5.5%) and gastrointestinal systems (4.7%), and hydrops fetalis (4.3%). The babies with major birth defects were associated with lower birth weights, premature deliveries, higher Caesarean section rates, prolonged hospitalization and increased specialist care. Among the cohort of babies with major birth defects, the mortality rate was 25.2% during the perinatal period. Mothers with affected babies were associated with advanced maternal age, birth defects themselves or their relatives but not in their other offspring, and significantly higher rates of previous abortions. The consanguinity rate of 2.4% was twice that of the control population. It is concluded that a birth defects register is needed to monitor these developments and future interventional trials are needed to reduce birth defects in Malaysia. PMID:16096215

  1. Sensitivity studies for a space-based methane lidar mission

    NASA Astrophysics Data System (ADS)

    Kiemle, C.; Quatrevalet, M.; Ehret, G.; Amediek, A.; Fix, A.; Wirth, M.

    2011-10-01

    Methane is the third most important greenhouse gas in the atmosphere after water vapour and carbon dioxide. A major handicap to quantify the emissions at the Earth's surface in order to better understand biosphere-atmosphere exchange processes and potential climate feedbacks is the lack of accurate and global observations of methane. Space-based integrated path differential absorption (IPDA) lidar has potential to fill this gap, and a Methane Remote Lidar Mission (MERLIN) on a small satellite in polar orbit was proposed by DLR and CNES in the frame of a German-French climate monitoring initiative. System simulations are used to identify key performance parameters and to find an advantageous instrument configuration, given the environmental, technological, and budget constraints. The sensitivity studies use representative averages of the atmospheric and surface state to estimate the measurement precision, i.e. the random uncertainty due to instrument noise. Key performance parameters for MERLIN are average laser power, telescope size, orbit height, surface reflectance, and detector noise. A modest-size lidar instrument with 0.45 W average laser power and 0.55 m telescope diameter on a 506 km orbit could provide 50-km averaged methane column measurement along the sub-satellite track with a precision of about 1% over vegetation. The use of a methane absorption trough at 1.65 μm improves the near-surface measurement sensitivity and vastly relaxes the wavelength stability requirement that was identified as one of the major technological risks in the pre-phase A studies for A-SCOPE, a space-based IPDA lidar for carbon dioxide at the European Space Agency. Minimal humidity and temperature sensitivity at this wavelength position will enable accurate measurements in tropical wetlands, key regions with largely uncertain methane emissions. In contrast to actual passive remote sensors, measurements in Polar Regions will be possible and biases due to aerosol layers and thin

  2. Sensitivity studies for a space-based methane lidar mission

    NASA Astrophysics Data System (ADS)

    Kiemle, C.; Quatrevalet, M.; Ehret, G.; Amediek, A.; Fix, A.; Wirth, M.

    2011-06-01

    Methane is the third most important greenhouse gas in the atmosphere after water vapour and carbon dioxide. A major handicap to quantify the emissions at the Earth's surface in order to better understand biosphere-atmosphere exchange processes and potential climate feedbacks is the lack of accurate and global observations of methane. Space-based integrated path differential absorption (IPDA) lidar has potential to fill this gap, and a Methane Remote Lidar Mission (MERLIN) on a small satellite in Polar orbit was proposed by DLR and CNES in the frame of a German-French climate monitoring initiative. System simulations are used to identify key performance parameters and to find an advantageous instrument configuration, given the environmental, technological, and budget constraints. The sensitivity studies use representative averages of the atmospheric and surface state to estimate the measurement precision, i.e. the random uncertainty due to instrument noise. Key performance parameters for MERLIN are average laser power, telescope size, orbit height, surface reflectance, and detector noise. A modest-size lidar instrument with 0.45 W average laser power and 0.55 m telescope diameter on a 506 km orbit could provide 50-km averaged methane column measurement along the sub-satellite track with a precision of about 1 % over vegetation. The use of a methane absorption trough at 1.65 μm improves the near-surface measurement sensitivity and vastly relaxes the wavelength stability requirement that was identified as one of the major technological risks in the pre-phase A studies for A-SCOPE, a space-based IPDA lidar for carbon dioxide at the European Space Agency. Minimal humidity and temperature sensitivity at this wavelength position will enable accurate measurements in tropical wetlands, key regions with largely uncertain methane emissions. In contrast to actual passive remote sensors, measurements in Polar Regions will be possible and biases due to aerosol layers and thin

  3. Birth Prevalence of Cerebral Palsy: A Population-Based Study

    PubMed Central

    Van Naarden Braun, Kim; Doernberg, Nancy; Schieve, Laura; Christensen, Deborah; Goodman, Alyson; Yeargin-Allsopp, Marshalyn

    2015-01-01

    OBJECTIVE Population-based data in the United States on trends in cerebral palsy (CP) birth prevalence are limited. The objective of this study was to examine trends in the birth prevalence of congenital spastic CP by birth weight, gestational age, and race/ethnicity in a heterogeneous US metropolitan area. METHODS Children with CP were identified by a population-based surveillance system for developmental disabilities (DDs). Children with CP were included if they were born in metropolitan Atlanta, Georgia, from 1985 to 2002, resided there at age 8 years, and did not have a postneonatal etiology (n = 766). Birth weight, gestational age, and race/ethnicity subanalyses were restricted to children with spastic CP (n = 640). Trends were examined by CP subtype, gender, race/ethnicity, co-occurring DDs, birth weight, and gestational age. RESULTS Birth prevalence of spastic CP per 1000 1-year survivors was stable from 1985 to 2002 (1.9 in 1985 to 1.8 in 2002; 0.3% annual average prevalence; 95% confidence interval [CI] −1.1 to 1.8). Whereas no significant trends were observed by gender, subtype, birth weight, or gestational age overall, CP prevalence with co-occurring moderate to severe intellectual disability significantly decreased (−2.6% [95% CI −4.3 to −0.8]). Racial disparities persisted over time between non-Hispanic black and non-Hispanic white children (prevalence ratio 1.8 [95% CI 1.5 to 2.1]). Different patterns emerged for non-Hispanic white and non-Hispanic black children by birth weight and gestational age. CONCLUSIONS Given improvements in neonatal survival, evidence of stability of CP prevalence is encouraging. Yet lack of overall decreases supports continued monitoring of trends and increased research and prevention efforts. Racial/ethnic disparities, in particular, warrant further study. PMID:26659459

  4. Fundamental Study for Introduction of Renewable Energy into Syowa Base

    NASA Astrophysics Data System (ADS)

    Nishikawa, Shogo; Abiko, Haruhiko; Kurihara, Junichi; Ishizawa, Kenji; Endo, Nobuhiko

    To reduce the volume of fuel consumed at Syowa base in Antarctica, we study the proper renewable energy system (RE system) to supply both electrical and thermal energy. Though a lot of photovoltaic power generation systems (PV systems) and wind power generation systems (WG systems) have already been installed all over the world, climate is quite different from other area and we have few experiences on renewable energy system in Antarctica. Moreover, though thermal load is much bigger than electrical load all the year round, both PV system and WG system generate only electrical energy. Therefore we proposed a power supply system composed of PV, WG and heat pump to convert a part of electrical energy to thermal energy. It is important to clear the proper system capacity, operational method of heat pump in this system. As a first step, we studied those items on this system without energy storage system by a simulation. We found that proper operational method of heat pump is affected by capacity of RE system and WG system is useful more than PV system.

  5. Space-based solar power conversion and delivery systems study

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Even at reduced rates of growth, the demand for electric power is expected to more than triple between now and 1995, and to triple again over the period 1995-2020. Without the development of new power sources and advanced transmission technologies, it may not be possible to supply electric energy at prices that are conductive to generalized economic welfare. Solar power is renewable and its conversion and transmission from space may be advantageous. The goal of this study is to assess the economic merit of space-based photovoltaic systems for power generation and a power relay satellite for power transmission. In this study, satellite solar power generation and transmission systems, as represented by current configurations of the Satellite Solar Station (SSPS) and the Power Relay Satellite (PRS), are compared with current and future terrestrial power generation and transmission systems to determine their technical and economic suitability for meeting power demands in the period of 1990 and beyond while meeting ever-increasing environmental and social constraints.

  6. Multiplex component-based allergen microarray in recent clinical studies.

    PubMed

    Patelis, A; Borres, M P; Kober, A; Berthold, M

    2016-08-01

    During the last decades component-resolved diagnostics either as singleplex or multiplex measurements has been introduced into the field of clinical allergology, providing important information that cannot be obtained from extract-based tests. Here we review recent studies that demonstrate clinical applications of the multiplex microarray technique in the diagnosis and risk assessment of allergic patients, and its usefulness in studies of allergic diseases. The usefulness of ImmunoCAP ISAC has been validated in a wide spectrum of allergic diseases like asthma, allergic rhinoconjunctivitis, atopic dermatitis, eosinophilic esophagitis, food allergy and anaphylaxis. ISAC provides a broad picture of a patient's sensitization profile from a single test, and provides information on specific and cross-reactive sensitizations that facilitate diagnosis, risk assessment, and disease management. Furthermore, it can reveal unexpected sensitizations which may explain anaphylaxis previously categorized as idiopathic and also display for the moment clinically non-relevant sensitizations. ISAC can facilitate a better selection of relevant allergens for immunotherapy compared with extract testing. Microarray technique can visualize the allergic march and molecular spreading in the preclinical stages of allergic diseases, and may indicate that the likelihood of developing symptomatic allergy is associated with specific profiles of sensitization to allergen components. ISAC is shown to be a useful tool in routine allergy diagnostics due to its ability to improve risk assessment, to better select relevant allergens for immunotherapy as well as detecting unknown sensitization. Multiplex component testing is especially suitable for patients with complex symptomatology. PMID:27196983

  7. Biologically based epidemiological studies of electric power and cancer.

    PubMed Central

    Stevens, R G

    1993-01-01

    As societies industrialize, the health profile of the population changes; in general, acute infectious disease declines and chronic disease increases. Use of electricity is a hallmark of the industrialization process, but there has been no suspicion that electricity could increase the risk of cancer. Recently, however, a number of epidemiologic studies have suggested that electromagnetic fields (EMF) may do just that. Although few cancer experiments have been done yet, there are a number of biological effects of EMF reported in the literature that might provide bases for designing cancer experiments and epidemiologic studies. These include effects of EMF on: a) DNA transcription and translation, b) calcium balance in cells, and c) pineal production of melatonin. Alterations in DNA transcription and translation could have pleiotropic effects. Disruption of calcium homeostasis has many implications including oncogene activation, promotional activity via protein kinases and ornithine decarboxylase (ODC), and increasing oxidative stress. Reduction of melatonin suggests a possible increased risk of cancers of hormone-dependent tissues such as breast and prostate. The idea that a cancer-causing agent must either be an initiator or a promoter should be discarded; indeed, the phenomenologic meaning of these two terms has become confused with imputed mechanistic necessity in recent years. Agents that affect division of normal cells or of fully transformed cells can play an important role in clinical cancer development quite apart from initiation or promotion.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8206047

  8. Gender-based education during clerkships: a focus group study

    PubMed Central

    van Leerdam, Lotte; Rietveld, Lianne; Teunissen, Doreth; Lagro-Janssen, Antoine

    2014-01-01

    Objectives One of the goals of the medical master’s degree is for a student to become a gender-sensitive doctor by applying knowledge of gender differences in practice. This study aims to investigate, from the students’ perspective, whether gender medicine has been taught in daily practice during clerkship. Methods A focus group study was conducted among 29 medical students from Radboud University, Nijmegen, The Netherlands, who had just finished either their internal medicine or surgical clerkships. Data were analyzed in line with the principles of constant comparative analysis. Results Four focus groups were conducted with 29 participating students. Clinical teachers barely discuss gender differences during students’ clerkships. The students mentioned three main explanatory themes: insufficient knowledge; unawareness; and minor impact. As a result, students feel that they have insufficient competencies to become gender-sensitive doctors. Conclusion Medical students at our institution perceive that they have received limited exposure to gender-based education after completing two key clinical clerkships. All students feel that they have insufficient knowledge to become gender-sensitive doctors. They suppose that their clinical teachers have insufficient knowledge regarding gender sensitivity, are unaware of gender differences, and the students had the impression that gender is not regarded as an important issue. We suggest that the medical faculty should encourage clinical teachers to improve their knowledge and awareness of gender issues. PMID:24600301

  9. Glycemic Change After Pancreaticoduodenectomy: A Population-Based Study.

    PubMed

    Wu, Jin-Ming; Ho, Te-Wei; Kuo, Ting-Chun; Yang, Ching-Yao; Lai, Hong-Shiee; Chiang, Pin-Yi; Hsieh, Su-Hua; Lai, Feipei; Tien, Yu-Wen

    2015-07-01

    The purpose of this population-based study was to determine the change of glucose metabolism in patients undergoing pancreaticoduodenectomy (PD).We conducted a nationwide cohort study using data from Taiwan's National Health Insurance Research Database collected between 2000 and 2010. Our sample included 861 subjects with type 2 diabetes mellitus (DM) and 3914 subjects without DM.Of 861 subjects with type 2 diabetes, 174 patients (20.2%) experienced resolution of their diabetes after PD, including patients with pancreatic ductal adenocarcinoma (PDAC) (20.5%), and non-PDAC (20.1%). Using a multiple logistic regression model, we found that subjects with comorbid chronic pancreatitis (odds ratio, 0.356; 95% CI, 0.167-0.759; P = 0.007) and use of insulin (odds ratio, 0.265; 95% CI, 0.171-0.412; P < 0.001) had significantly lower rates of resolution of diabetes. In the 3914 subjects without diabetes, the only statistically significant comorbidity contributing to pancreatogenic diabetes was chronic pancreatitis (odds ratio, 1.446; 95% CI, 1.146-1.823; P = 0.002).Subjects with comorbid chronic pancreatitis and use of insulin had lower rates of resolution of DM after PD. In subjects without diabetes, chronic pancreatitis contributed significantly to the development of pancreatogenic DM. PMID:26166104

  10. Studies on biological macromolecules lipid-Gelucire based gastroretentive multiparticulate.

    PubMed

    Upadhyay, Prashant; Pandit, Jayanta Kumar; Wahi, Arun Kumar

    2014-06-01

    Studies on biological macromolecules lipid-Gelucire based sustained release gastroretentive multiparticulates of metformin hydrochloride (MH) were developed by dispersing MH in melted Gelucire 39/01 and 43/01 using the melt granulation technique while fast release solid dispersions gastroretentive multiparticulates of glibenclamide (GLB), poorly soluble drug were developed using Gelucire 50/13 and PEG 200, 400, 4000, 6000 as carrier at different ratios. Percent drug entrapment of MH was 99.6±0.35% and in vitro floating ability was 11.3±0.47h. Model dependent analysis shows that zero order kinetics was followed while drug release mechanism was anomalous diffusion controlled. Combination of ethylcellulose, methylcellulose and microcrystalline cellulose with Gelucire were explored for release of drug, floatability and consistency for optimized formulation. While GLB multiparticulates showed entrapment efficiency of 99.8±0.11%, in vitro buoyancy for 11±0.2h and improved solubility and dissolution rate. Zero order kinetics was promising for all formulations. Model independent analysis f2 value for GIV was 40 while for M II was 54. Characterization was done by SEM, FTIR and PXRD. RP-HPLC method was adopted for simultaneous pharmacokinetic analysis of the drugs in rat plasma. In IVIVC studies confirm increased bioavailability of drugs in combination form and followed level A correlation using the diabetic type II Wistar rat. PMID:24699418

  11. A Web-based Geovisual Analytical System for Climate Studies

    NASA Astrophysics Data System (ADS)

    Sun, M.; Li, J.; Yang, C.; Schmidt, G. A.; Bambacus, M.; Cahalan, R.; Huang, Q.; Xu, C.; Noble, E.

    2012-12-01

    Climate studies involve petabytes of spatiotemporal datasets that are produced and archived at distributed computing resources. Scientists need an intuitive and convenient tool to explore the distributed spatiotemporal data. Geovisual analytical tools have the potential to provide such an intuitive and convenient method for scientists to access climate data, discover the relationships between various climate parameters, and communicate the results across different research communities. However, implementing a geovisual analytical tool for complex climate data in a distributed environment poses several challenges. This paper reports our efforts in developing a web-based geovisual analytical system to support the analysis of climate data generated by Intergovernmental Panel on Climate Change (IPCC), Fourth Assessment Report (AR4) models. Using the ModelE developed by NASA Goddard Institute for Space Studies (GISS) as an example, we demonstrate that the system is able to 1) manage large volume datasets over the Internet, 2) visualize 3D/4D spatiotemporal data, 3) broker various spatiotemporal statistical analyses for climate research, and 4) support interactive data analysis and knowledge discovery. This research also provides an example of how to manage, disseminate, and analyze Big Data in the 21st century.

  12. Genome-wide gene-based association study.

    PubMed

    Yang, Hsin-Chou; Liang, Yu-Jen; Chung, Chia-Min; Chen, Jia-Wei; Pan, Wen-Harn

    2009-01-01

    Genome-wide association studies, which analyzes hundreds of thousands of single-nucleotide polymorphisms to identify disease susceptibility genes, are challenging because the work involves intensive computation and complex modeling. We propose a two-stage genome-wide association scanning procedure, consisting of a single-locus association scan for the first stage and a gene-based association scan for the second stage. Marginal effects of single-nucleotide polymorphisms are examined by using the exact Armitage trend test or logistic regression, and gene effects are examined by using a p-value combination method. Compared with some existing single-locus and multilocus methods, the proposed method has the following merits: 1) convenient for definition of biologically meaningful regions, 2) powerful for detection of minor-effect genes, 3) helpful for alleviation of a multiple-testing problem, and 4) convenient for result interpretation. The method was applied to study Genetic Analysis Workshop 16 Problem 1 rheumatoid arthritis data, and strong association signals were found. The results show that the human major histocompatibility complex region is the most important genomic region associated with rheumatoid arthritis. Moreover, previously reported genes including PTPN22, C5, and IL2RB were confirmed; novel genes including HLA-DRA, BTNL2, C6orf10, NOTCH4, TAP2, and TNXB were identified by our analysis. PMID:20018002

  13. Study of the Topological-insulator-based Topological Superconductors

    NASA Astrophysics Data System (ADS)

    Qian, Dong

    Three-dimensional topological insulators possess nontrivial spin-momentum locked surface states under the protection of time-reversal symmetry. The interplay between topological order and superconductivity can lead to topological superconducting state. In this talk, I will discuss our recent progress in topological-insulator-based topological superconductors. Using molecular beam epitaxy (MBE) method, we succeeded in fabricating very high quality TI/s-wave superconductor heterostructure by growing topological insulator thin films on the conventional superconductor niobium diselenide (NbSe2) substrate. Using low temperature scanning tunneling microscopy/spectroscopy (STM/STS) and angle-resolved photoemission spectroscopy (ARPES), we systematically studied its electronic structure and superconducting behavior. Through superconducting proximity effect, coexistence of Cooper pairs and topological surface states on the surface of topological insulator film was realized. By exploring the superconducting vortex core state as the function of film thickness, existing of nontrivial superconducting state on the TI's surface was proposed. Our topological insulator/superconductor heterostructure may host single zero-energy Majorana mode in the vortex core. In addition, I will also discuss STM and ARPES studies on the recently discovered superconducting Sr-doped Bi2Se3 bulk crystals. Our results suggest that Sr-doped Bi2Se3 could be an excellent candidate for exploring topological superconducting states. Supported by the Ministry of Science and Technology of China and NSFC.

  14. Synthesis, structural and fungicidal studies of hydrazone based coordination compounds

    NASA Astrophysics Data System (ADS)

    Sharma, Amit Kumar; Chandra, Sulekh

    2013-02-01

    The coordination compounds of the Co(II), Ni(II) and Cu(II) metal ions derived from imine based ligand, benzil bis(carbohydarzone) were structurally and pharmaceutically studied. The compounds have the general stoichiometry [M(L)]X2 and [Co(L)X2], where M = Ni(II) and Cu(II), and X=NO3- and Cl- ions. The analytical techniques like elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, UV/Visible, NMR, ESI mass and EPR were used to study the compounds. The key IR bands, i.e., amide I, amide II and amide III stretching vibrations accounts for the tetradentate metal binding nature of the ligand. The electronic and EPR spectral results suggest the square planar Ni(II) and Cu(II) complexes (giso = 2.11-2.22) and tetragonal geometry Co(II) complexes (giso = 2.10-2.17). To explore the compounds in the biological field, they were examined against the opportunistic pathogens, i.e., Alternaria brassicae, Aspergillus niger and Fusarium oxysporum. The partial covalent character of metal-ligand bond is supported by the orbital reduction factor k (0.62-0.92) and nephalauxetic parameter β (0.55-0.57).

  15. Study design in evidence-based surgery: What is the role of case-control studies?

    PubMed Central

    Cao, Amy M; Cox, Michael R; Eslick, Guy D

    2016-01-01

    Randomized controlled trials (RCTs) are the gold standard in terms of study design, however, in the surgical setting conducting RCTs can often be unethical or logistically impossible. Case-control studies should become the major study design used in surgical research when RCTs are unable to be conducted and definitely replacing case series which offer little insight into surgical outcomes and disease processes. PMID:27019801

  16. Electrical studies on silver based fast ion conducting glassy materials

    SciTech Connect

    Rao, B. Appa Kumar, E. Ramesh Kumari, K. Rajani Bhikshamaiah, G.

    2014-04-24

    Among all the available fast ion conductors, silver based glasses exhibit high conductivity. Further, glasses containing silver iodide enhances fast ion conducting behavior at room temperature. Glasses of various compositions of silver based fast ion conductors in the AgI−Ag{sub 2}O−[(1−x)B{sub 2}O{sub 3}−xTeO{sub 2}] (x=0 to1 mol% in steps of 0.2) glassy system have been prepared by melt quenching method. The glassy nature of the compounds has been confirmed by X-ray diffraction. The electrical conductivity (AC) measurements have been carried out in the frequency range of 1 KHz–3MHz by Impedance Analyzer in the temperature range 303–423K. The DC conductivity measurements were also carried out in the temperature range 300–523K. From both AC and DC conductivity studies, it is found that the conductivity increases and activation energy decreases with increasing the concentration of TeO{sub 2} as well as with temperature. The conductivity of the present glass system is found to be of the order of 10{sup −2} S/cm at room temperature. The ionic transport number of these glasses is found to be 0.999 indicating that these glasses can be used as electrolyte in batteries.

  17. Secured web-based video repository for multicenter studies

    PubMed Central

    Yan, Ling; Hicks, Matt; Winslow, Korey; Comella, Cynthia; Ludlow, Christy; Jinnah, H. A; Rosen, Ami R; Wright, Laura; Galpern, Wendy R; Perlmutter, Joel S

    2015-01-01

    Background We developed a novel secured web-based dystonia video repository for the Dystonia Coalition, part of the Rare Disease Clinical Research network funded by the Office of Rare Diseases Research and the National Institute of Neurological Disorders and Stroke. A critical component of phenotypic data collection for all projects of the Dystonia Coalition includes a standardized video of each participant. We now describe our method for collecting, serving and securing these videos that is widely applicable to other studies. Methods Each recruiting site uploads standardized videos to a centralized secured server for processing to permit website posting. The streaming technology used to view the videos from the website does not allow downloading of video files. With appropriate institutional review board approval and agreement with the hosting institution, users can search and view selected videos on the website using customizable, permissions-based access that maintains security yet facilitates research and quality control. Results This approach provides a convenient platform for researchers across institutions to evaluate and analyze shared video data. We have applied this methodology for quality control, confirmation of diagnoses, validation of rating scales, and implementation of new research projects. Conclusions We believe our system can be a model for similar projects that require access to common video resources. PMID:25630890

  18. Electrical studies on silver based fast ion conducting glassy materials

    NASA Astrophysics Data System (ADS)

    Rao, B. Appa; Kumar, E. Ramesh; Kumari, K. Rajani; Bhikshamaiah, G.

    2014-04-01

    Among all the available fast ion conductors, silver based glasses exhibit high conductivity. Further, glasses containing silver iodide enhances fast ion conducting behavior at room temperature. Glasses of various compositions of silver based fast ion conductors in the AgI-Ag2O-[(1-x)B2O3-xTeO2] (x=0 to1 mol% in steps of 0.2) glassy system have been prepared by melt quenching method. The glassy nature of the compounds has been confirmed by X-ray diffraction. The electrical conductivity (AC) measurements have been carried out in the frequency range of 1 KHz-3MHz by Impedance Analyzer in the temperature range 303-423K. The DC conductivity measurements were also carried out in the temperature range 300-523K. From both AC and DC conductivity studies, it is found that the conductivity increases and activation energy decreases with increasing the concentration of TeO2 as well as with temperature. The conductivity of the present glass system is found to be of the order of 10-2 S/cm at room temperature. The ionic transport number of these glasses is found to be 0.999 indicating that these glasses can be used as electrolyte in batteries.

  19. Novel dipodal Schiff base compounds: Synthesis, characterization and spectroscopic studies

    NASA Astrophysics Data System (ADS)

    Obali, Aslihan Yilmaz; Ucan, Halil Ismet

    2015-02-01

    Two novel dipodal Schiff base compounds 1,2-benzyloxy-bis-[2-(benzylideneamino)phenol, L1 and 1,2-benzyloxy-bis[3-(benzylideneamino)pyridine], L2 were synthesized. Their sensing actions were confirmed by UV-Vis absorbance and emission spectroscopic studies in presence of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Sn(II), Cd(II) and Pb(II) in methanol medium (1 × 10-4 M). It was found that the dipodal compounds can selectively bind to Cu(II) and Pb(II) metal ions with a significant change in its emission and absorption spectra, while the addition of other metal ions (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Sn(II), Cd(II) and Pb(II)) produces insignificant or minor changes. The host-guest complexes formed were determined by Job's plot method. As a chemosensor, L1 and L2 dipodal Schiff base compounds shows a specific selectivity towards Cu(II) and Pb(II) ions in according to all spectroscopic data.

  20. Study of novel rosin-based biomaterials for pharmaceutical coating.

    PubMed

    Fulzele, Suniket V; Satturwar, Prashant M; Dorle, Avinash K

    2002-01-01

    The film forming and coating properties of Glycerol ester of maleic rosin (GMR) and Pentaerythritol ester of maleic rosin (PMR) were investigated. The 2 rosin-based biomaterials were initially characterized in terms of their physicochemical properties, molecular weight (Mw), and glass transition temperature (Tg). Films were produced by solvent evaporation technique on a mercury substrate. Dibutyl sebacate plasticized and nonplasticized films were characterized by mechanical (tensile zzzz strength, percentage elongation, and Young's modulus), water vapor transmission (WVT), and moisture absorption parameters. Plasticization was found to increase film elongation and decrease the Young's modulus, making the films more flexible and thereby reducing the brittleness. Poor rates of WVT and percentage moisture absorption were demonstrated by various film formulations. Diclofenac sodium-layered pellets coated with GMR and PMR film formulations showed sustained drug release for up to 10 hours. The release rate was influenced by the extent of plasticization and coating level. The results obtained in the study demonstrate the utility of novel rosin-based biomaterials for pharmaceutical coating and sustained-release drug delivery systems. PMID:12916925

  1. Space-based laser-driven MHD generator: Feasibility study

    NASA Technical Reports Server (NTRS)

    Choi, S. H.

    1986-01-01

    The feasibility of a laser-driven MHD generator, as a candidate receiver for a space-based laser power transmission system, was investigated. On the basis of reasonable parameters obtained in the literature, a model of the laser-driven MHD generator was developed with the assumptions of a steady, turbulent, two-dimensional flow. These assumptions were based on the continuous and steady generation of plasmas by the exposure of the continuous wave laser beam thus inducing a steady back pressure that enables the medium to flow steadily. The model considered here took the turbulent nature of plasmas into account in the two-dimensional geometry of the generator. For these conditions with the plasma parameters defining the thermal conductivity, viscosity, electrical conductivity for the plasma flow, a generator efficiency of 53.3% was calculated. If turbulent effects and nonequilibrium ionization are taken into account, the efficiency is 43.2%. The study shows that the laser-driven MHD system has potential as a laser power receiver for space applications because of its high energy conversion efficiency, high energy density and relatively simple mechanism as compared to other energy conversion cycles.

  2. A population-based study of large granular lymphocyte leukemia.

    PubMed

    Shah, M V; Hook, C C; Call, T G; Go, R S

    2016-01-01

    Large granular lymphocyte (LGL) leukemia is a lymphoproliferative disorder of cytotoxic cells. T-cell LGL (T-LGL) leukemia is characterized by accumulation of cytotoxic T cells in blood and infiltration of the bone marrow, liver or spleen. Population-based studies have not been reported in LGL leukemia. We present clinical characteristics, natural history and risk factors for poor survival in patients with LGL leukemia using the Surveillance, Epidemiology, and End Results Program (SEER) and the United States National Cancer Data Base (NCDB). LGL leukemia is an extremely rare disease with the incidence of 0.2 cases per 1 000 000 individuals. The median age at diagnosis was 66.5 years with females likely to be diagnosed at 3 years earlier compared with males. Analysis of patient-level data using NCDB (n=978) showed that 45% patients with T-LGL leukemia required some form of systemic treatment at the time of diagnosis. T-LGL leukemia patients have reduced survival compared with general population, with a median overall survival of 9 years. Multivariate analysis showed that age >60 years at the time of diagnosis and the presence of significant comorbidities were independent predictors of poor survival. PMID:27494824

  3. A missing variable in the data-based substorm studies

    NASA Astrophysics Data System (ADS)

    Sergeev, Viktor; Angelopoulos, Vassilis; Sormakov, Dmitry

    Nowadays the quantitative characterization of the magnetospheric activity is predominantly based on the amplitude of auroral zone magnetic perturbations (e.g., AL index value). This approach ignores the long-established fact that ground magnetic perturbations are basically formed by the Hall currents (Fukushima theorem), which depend critically on the Hall conductivity and, therefore, are sensitive to the plasma sheet electron parameters (Te and Ne, which also control the production of energetic electrons by their field-aligned acceleration). Observational confirmation of such influence is difficult because of many complicating factors, main of which are the inhomogeneity of Te, Ne parameters in the magnetotail and, especially, the reconnection-induced production of low-density and high-temperature electrons during substorms in the magnetotail. In this study, based on long-term monitoring of plasma sheet electrons by THEMIS spacecraft, we (a) demonstrate a strong variation of auroral zone currents (by an order of magnitude depending on the plasma sheet Te/Ne value) under the conditions of the substorm growth phase (when substorm-related acceleration is weak), (b) compare the average behaviors of Te, Ne during substorms under very large (very small) Te/Ne conditions and (c) briefly discuss a number of ’phantom problems’ which arise due to the ignorance of this dependence (incl. the problem of pseudobreakups, etc).

  4. Ablation study of tungsten-based nuclear thermal rocket fuel

    NASA Astrophysics Data System (ADS)

    Smith, Tabitha Elizabeth Rose

    The research described in this thesis has been performed in order to support the materials research and development efforts of NASA Marshall Space Flight Center (MSFC), of Tungsten-based Nuclear Thermal Rocket (NTR) fuel. The NTR was developed to a point of flight readiness nearly six decades ago and has been undergoing gradual modification and upgrading since then. Due to the simplicity in design of the NTR, and also in the modernization of the materials fabrication processes of nuclear fuel since the 1960's, the fuel of the NTR has been upgraded continuously. Tungsten-based fuel is of great interest to the NTR community, seeking to determine its advantages over the Carbide-based fuel of the previous NTR programs. The materials development and fabrication process contains failure testing, which is currently being conducted at MSFC in the form of heating the material externally and internally to replicate operation within the nuclear reactor of the NTR, such as with hot gas and RF coils. In order to expand on these efforts, experiments and computational studies of Tungsten and a Tungsten Zirconium Oxide sample provided by NASA have been conducted for this dissertation within a plasma arc-jet, meant to induce ablation on the material. Mathematical analysis was also conducted, for purposes of verifying experiments and making predictions. The computational method utilizes Anisimov's kinetic method of plasma ablation, including a thermal conduction parameter from the Chapman Enskog expansion of the Maxwell Boltzmann equations, and has been modified to include a tangential velocity component. Experimental data matches that of the computational data, in which plasma ablation at an angle shows nearly half the ablation of plasma ablation at no angle. Fuel failure analysis of two NASA samples post-testing was conducted, and suggestions have been made for future materials fabrication processes. These studies, including the computational kinetic model at an angle and the

  5. A Population-based study of dementia in the oldest old: the Monzino 80-plus Study

    PubMed Central

    2011-01-01

    Background Despite being the fastest growing and the most cognitively impaired age group, the oldest olds are under-represented in clinical research. The purpose of this study was to describe the design, methods, and baseline characteristics of the survey population and investigate possible differences in demographic, cognitive, functional, and behavioral characteristics between oldest old with and without any performance on cognitive tests and between oldest old alive and those deceased prior to the interview. Methods The Monzino 80-plus Study is a prospective door-to-door population-based survey among 80 years or older residents in the municipalities in the province of Varese, Italy. Dementia cases were identified with a one-phase design. Trained psychologists interviewed both the subject and a proxy informant. The interview included a comprehensive standardized questionnaire together with an array of rating scales and a multidomain cognitive battery to assess cognitive and functional ability, behavioral disturbances and mood. Results Information was available for 2,139 of the 2,428 registered individuals aged 80 years or older. Main baseline characteristics of the population are reported and discussed. In comparison with those living, elderly persons who had died before the first visit were older, had twice the rate of institutionalization, poorer cognitive performance and competence, and significantly greater instrumental and basic functional disability. The percentage of elderly persons, alive at baseline, without Mini-Mental State Examination rose rather evenly with age. Moreover, they had significantly worse cognitive competence and functional ability, and reported higher prevalences of depressive symptoms and problem behaviors than those with Mini-Mental State Examination. Conclusions Prospective investigation of a large population of oldest old can contribute significantly to understanding the relations between age, cognitive decline, and dementia

  6. Parameterizations for shielding electron accelerators based on Monte Carlo studies

    SciTech Connect

    P. Degtyarenko; G. Stapleton

    1996-10-01

    Numerous recipes for designing lateral slab neutron shielding for electron accelerators are available and each generally produces rather similar results for shield thicknesses of about 2 m of concrete and for electron beams with energy in the 1 to 10 GeV region. For thinner or much thicker shielding the results tend to diverge and the standard recipes require modification. Likewise for geometries other than lateral to the beam direction further corrections are required so that calculated results are less reliable and hence additional and costly conservatism is needed. With the adoption of Monte Carlo (MC) methods of transporting particles a much more powerful way of calculating radiation dose rates outside shielding becomes available. This method is not constrained by geometry, although deep penetration problems need special statistical treatment, and is an excellent approach to solving any radiation transport problem providing the method has been properly checked against measurements and is free from the well known errors common to such computer methods. This present paper utilizes the results of MC calculations based on a nuclear fragmentation model named DINREG using the MC transport code GEANT and models them with the normal two parameter shielding expressions. Because the parameters can change with electron beam energy, angle to the electron beam direction and target material, the parameters are expressed as functions of some of these variables to provide a universal equations for shielding electron beams which can used rather simply for deep penetration problems in simple geometry without the time consuming computations needed in the original MC programs. A particular problem with using simple parameterizations based on the uncollided flux is that approximations based on spherical geometry might not apply to the more common cylindrical cases used for accelerator shielding. This source of error has been discussed at length by Stevenson and others. To study

  7. Risk-based monitored natural attenuation--a case study.

    PubMed

    Khan, F I; Husain, T

    2001-08-17

    The term "monitored natural attenuation" (MNA) refers to a reliance on natural attenuation (NA) processes for remediation through the careful monitoring of the behavior of a contaminant source in time and space domains. In recent years, policymakers are shifting to a risk-based approach where site characteristics are measured against the potential risk to human health and the environment, and site management strategies are prioritized to be commensurate with that risk. Risk-based corrective action (RBCA), a concept developed by the American Society for Testing Materials (ASTM), was the first indication of how this approach could be used in the development of remediation strategies. This paper, which links ASTM's RBCA approach with MNA, develops a systematic working methodology for a risk-based site evaluation and remediation through NA. The methodology is comprised of seven steps, with the first five steps intended to evaluate site characteristics and the feasibility of NA. If NA is effective, then the last two steps will guide the development of a long-term monitoring plan and approval for a site closure. This methodology is used to evaluate a site contaminated with oil from a pipeline spill. The case study concluded that the site has the requisite characteristics for NA, but it would take more than 80 years for attenuation of xylene and ethylbenzene, as these chemicals appear in the pure phase. If fast remediation is sought, then efforts should be made to remove the contaminant from the soil. Initially, the site posed a serious risk to both on-site and off-site receptors, but it becomes acceptable after 20 years, as the plume is diluted and drifts from its source of origin. PMID:11489527

  8. A Whole-Language Base for Theme Studies in the Social Studies Curriculum.

    ERIC Educational Resources Information Center

    Lamme, Linda Leonard; Hysmith, Cecilia

    1993-01-01

    Asserts that the whole-language approach is a philosophy of learning in which children construct knowledge by actively engaging in classroom projects that have real meaning for them. Describes thematic studies using a whole-language approach in which children (with teacher assistance) decide what themes will be studied. (CFR)

  9. Technology base studies of long-term MCFC performance

    SciTech Connect

    Selman, J.R.

    1995-08-01

    Cathode dissolution into the electrolyte matrix and endurance of current collector/separator plate materials are the main life-limiting factors of the state-of-the art MCFC. These components are also major contributors to the total system cost. Therefore, to reduce capital cost, it is necessary to minimize hardware corrosion and increase cell life. This study consists of experimental evaluation of corrosion processes with the objective to further practical; understanding of corrosion behavior of alloys and alloy components under cathodic gas conditions. Nickel, iron, cobalt and stainless steels 310 and 316L are analyzed. The experimental study consists of (1) Observation of open circuit potential (OCP) changes. Surface reactions occurring without net passage of current are proposed based on this measurement. (2) Applying cyclic voltammetry, which provides information about the possible electrode reactions at different stages of polarization. (3) Applying AC impedance to support the result of tasks 1 and 2 at different stages of oxidation, and data analysis by means of equivalent circuits. Open circuit conditions as well as positive and negative polarization are used in the impedance measurements. (4) Surface analysis of the electrodes by SEM-EDX and X-ray diffraction. To obtain more information from electrochemical measurements a novel approach has been applied in cell design. In this two-electrode approach, one electrode is fully immersed, and the other is wetted by carbonate melt via an alumina tube which has a thin film on it. While camera observation of these two different electrode conditions will identify the effect of carbonate wetting on the state of the surface, electrochemical measurements enable a quantitative comparison between complete submersion and wetting by a film of carbonate.

  10. RP-1 Thermal Stability and Copper Based Materials Compatibility Study

    NASA Technical Reports Server (NTRS)

    Stiegemeier, B. R.; Meyer, M. L.; Driscoll, E.

    2005-01-01

    A series of electrically heated tube tests was performed at the NASA Glenn Research Center s Heated Tube Facility to investigate the effect that sulfur content, test duration, and tube material play in the overall thermal stability and materials compatibility characteristics of RP-1. Scanning-electron microscopic (SEM) analysis in conjunction with energy dispersive spectroscopy (EDS) were used to characterize the condition of the tube inner wall surface and any carbon deposition or corrosion formed during these runs. Results of the parametric study indicate that tests with standard RP-1 (total sulfur -23 ppm) and pure copper tubing are characterized by a depostion/deposit shedding process producing local wall temperature swings as high as 500 F. The effect of this shedding is to keep total carbon deposition levels relatively constant for run times from 20 minutes up to 5 hours, though increasing tube pressure drops were observed in all runs. Reduction in the total sulfur content of the fuel from 23 ppm to less than 0.1 ppm resulted in the elimination of deposit shedding, local wall temperature variation, and the tube pressure drop increases that were observed in standard sulfur level RP-1 tests. The copper alloy GRCop-84, a copper alloy developed specifically for high heat flux applications, was found to exhibit higher carbon deposition levels compared to identical tests performed in pure copper tubes. Results of the study are consistent with previously published heated tube data which indicates that small changes in fuel total sulfur content can lead to significant differences in the thermal stability of kerosene type fuels and their compatibility with copper based materials. In conjunction with the existing thermal stability database, these findings give insight into the feasibility of cooling a long life, high performance, high-pressure liquid rocket combustor and nozzle with RP-1.

  11. Model Based Systems Engineering on the Europa Mission Concept Study

    NASA Technical Reports Server (NTRS)

    Bayer, Todd J.; Chung, Seung; Cole, Bjorn; Cooke, Brian; Dekens, Frank; Delp, Chris; Gontijo, I.; Lewis, Kari; Moshir, Mehrdad; Rasmussen, Robert; Wagner, Dave

    2012-01-01

    At the start of 2011, the proposed Jupiter Europa Orbiter (JEO) mission was staffing up in expectation of becoming an official project later in the year for a launch in 2020. A unique aspect of the pre-project work was a strong emphasis and investment on the foundations of Model-Based Systems Engineering (MBSE). As so often happens in this business, plans changed: NASA's budget and science priorities were released and together fundamentally changed the course of JEO. As a result, it returned to being a study task whose objective is to propose more affordable ways to accomplish the science. As part of this transition, the question arose as to whether it could continue to afford the investment in MBSE. In short, the MBSE infusion has survived and is providing clear value to the study effort. By leveraging the existing infrastructure and a modest additional investment, striking advances in the capture and analysis of designs using MBSE were achieved. In the process, the need to remain relevant in the new environment has brought about a wave of innovation and progress. The effort has reaffirmed the importance of architecting. It has successfully harnessed the synergistic relationship of architecting to system modeling. We have found that MBSE can provide greater agility than traditional methods. We have also found that a diverse 'ecosystem' of modeling tools and languages (SysML, Mathematica, even Excel) is not only viable, but an important enabler of agility and adaptability. This paper will describe the successful application of MBSE in the dynamic environment of early mission formulation, the significant results produced and lessons learned in the process.

  12. Technology base studies of long-term MCFC performance

    SciTech Connect

    Selman, J.R.; Yazici, M.S.

    1995-12-01

    Cathode dissolution into the electrolyte matrix and endurance of current collector/separator plate materials are the main life-limiting factors of the state-of-the art MCFC. These components are also major contributors to the total system cost. Therefore, to reduce capital cost, it is necessary to minimize hardware corrosion and increase cell life. This study consists of experimental evaluation of corrosion processes with the objective to further practical; understanding of corrosion behavior of alloys and alloy components under cathodic gas conditions. Nickel, iron, cobalt and stainless steels 310 and 316L are analyzed. The experimental study consists of: (1) Observation of open circuit potential (OCP) changes. Surface reactions occurring without net passage of current are proposed based on this measurement. (2) Applying cyclic voltammetry, which provides information about the possible electrode reactions at different stages of polarization. (3) Applying AC impedance to support the result of tasks 1 and 2 at different stages of oxidation, and data analysis by means of equivalent circuits. Open circuit conditions as well as positive and negative polarization are used in the impedance measurements. (4) Surface analysis of the electrodes by SEM-EDX and X-ray diffraction. To obtain more information from electrochemical measurements a novel approach has been applied in cell design. In this two electrode approach, one electrode is fully immersed, and the other is wetted by carbonate melt via an alumina tube which has a thin film on it. While camera observation of these two different electrode conditions will identify the effect of carbonate wetting on the state of the surface, electrochemical measurements enable a quantitative comparison between complete submersion and wetting by a film of carbonate.

  13. Behavior-based safety on construction sites: a case study.

    PubMed

    Choudhry, Rafiq M

    2014-09-01

    This work presents the results of a case study and describes an important area within the field of construction safety management, namely behavior-based safety (BBS). This paper adopts and develops a management approach for safety improvements in construction site environments. A rigorous behavioral safety system and its intervention program was implemented and deployed on target construction sites. After taking a few weeks of safety behavior measurements, the project management team implemented the designed intervention and measurements were taken. Goal-setting sessions were arranged on-site with workers' participation to set realistic and attainable targets of performance. Safety performance measurements continued and the levels of performance and the targets were presented on feedback charts. Supervisors were asked to give workers recognition and praise when they acted safely or improved critical behaviors. Observers were requested to have discussions with workers, visit the site, distribute training materials to workers, and provide feedback to crews and display charts. They were required to talk to operatives in the presence of line managers. It was necessary to develop awareness and understanding of what was being measured. In the process, operatives learned how to act safely when conducting site tasks using the designed checklists. Current weekly scores were discussed in the weekly safety meetings and other operational site meetings with emphasis on how to achieve set targets. The reliability of the safety performance measures taken by the company's observers was monitored. A clear increase in safety performance level was achieved across all categories: personal protective equipment; housekeeping; access to heights; plant and equipment, and scaffolding. The research reveals that scores of safety performance at one project improved from 86% (at the end of 3rd week) to 92.9% during the 9th week. The results of intervention demonstrated large decreases in

  14. Project Based Learning for Life Skill Building in 12th Grade Social Studies Classrooms: A Case Study

    ERIC Educational Resources Information Center

    Zimmerman, Daniele C.

    2010-01-01

    Based on the assumption that project based learning (PBL) in 12th grade social studies classrooms contributes to the development of life skills for high school seniors in this advanced and globalized time, this research will investigate student experiences with PBL methods for helping them acquire skills along with a case study of a successful PBL…

  15. Cyberbullying among Finnish adolescents – a population-based study

    PubMed Central

    2012-01-01

    Background Cyberbullying, threatening or harassing another via the internet or mobile phones, does not cause physically harm and thus the consequences are less visible. Little research has been performed on the occurrence of cyberbullying among adolescents or the perception of its seriousness. Only a few population-based studies have been published, none of which included research on the witnessing of cyberbullying. Here, we examined exposure to cyberbullying during the last year, and its frequency and perceived seriousness among 12 to 18-year-old adolescents in Finland. We studied four dimensions of cyberbullying: being a victim, bully, or both victim and bully of cyberbullying, and witnessing the cyberbullying of friends. Methods Self-administered questionnaires, including four questions on cyberbullying, were mailed to a representative sample of 12-, 14-, 16-, and 18-year-old Finns in 2009 (the Adolescent Health and Lifestyle Survey). The respondents could answer via the internet or paper questionnaire. Results The number of respondents was 5516 and the response rate was 56%. Girls more often than boys reported experiencing at least one dimension of cyberbullying during the last year. The proportion was highest among 14-year-olds and lowest among 18-year-olds of both sexes. Among girls, the most commonly encountered dimension was witnessing the cyberbullying of friends (16%); and being a victim was slightly more common than being a bully (11% vs. 9%). Among boys, an equal proportion, approximately 10%, had been a victim, a bully, or had witnessed cyberbullying. The proportion of bully-victims was 4%. Serious and disruptive cyberbullying was experienced by 2% of respondents and weekly cyberbullying by 1%; only 0.5% of respondents had been bullied weekly and considered bullying serious and disruptive. Conclusions Adolescents are commonly exposed to cyberbullying, but it is rarely frequent or considered serious or disruptive. Cyberbullying exposure differed between

  16. Retinal Detachment in Southwest Ethiopia: A Hospital Based Prospective Study

    PubMed Central

    Asaminew, Tsedeke; Gelaw, Yeshigeta; Bekele, Sisay; Solomon, Berhan

    2013-01-01

    Purpose The incidence of retinal detachment in Blacks is generally considered to be low though there are few supporting studies in Africa. This study, thus, aimed at describing the clinical profile of patients with retinal detachment in Southwest Ethiopia. Methods A hospital-based study was done on all consecutive retinal detachment patients who presented to Jimma University Hospital over six months period. A semi-structured questionnaire was used to collect patients’ sociodemographic characteristics and clinical history. Comprehensive anterior and posterior segment eye examinations were done and risk factors were sought for. Statistical tests were considered significant if P < 0.05. Results A total of 94 eyes of 80 patients (1.5%) had retinal detachment (RD) and about 69% of patients were symptomatic for over a month before presentation. The mean age was 41.4 years (SD ±16.5). Fourteen patients (17.5%) had bilateral RD. At presentation, 61 eyes (64.9%) were blind from RD and 11 (13.8%) patients were bilaterally blind from RD. Rhegmatogenous RD was seen in 55 eyes (58.5%) and tractional RD in 22 eyes (23.4%). The most common risk factors were ocular trauma (32 eyes, 34.0%), myopia (23 eyes, 24.5%), posterior uveitis (13 eyes, 13.8%) and diabetic retinopathy (9 eyes, 9.6%). Most retinal breaks (25 eyes, 43.1%) were superotemporal and horse-shoe tear was the most common (19 eyes, 20.2%). Macula was off in 77 eyes (81.9%) and 38 eyes (69.1% of RRD eyes) had grade C proliferative vitreoretinopathy (PVR). Macular status was significantly associated with PVR (P=0.011), and duration of symptoms (RR=1.25, 95%CI: 1.059-1.475, P=0.040). Conclusions A significant numbers of patients with ocular problem had retinal detachment, and nearly two third of the patients presented late. Trauma and myopia were the most important risk factors. People should be educated to improve their health seeking behavior and use eye safety precautions to prevent ocular trauma. PMID:24086614

  17. Studying the Multilingual City: A GIS-Based Approach

    ERIC Educational Resources Information Center

    Veselinova, Ljuba Nikolova; Booza, J. C.

    2009-01-01

    Work in two distinct disciplines, urban geography and sociolinguistics, readily points out the multiethnic and multilingual character of metropolitan areas. However, there is still demand for studies which establish the language structure of modern cities. For the purposes of this pilot study, we focus on the Detroit Metropolitan Area (DMA),…

  18. Videogames, Tools for Change: A Study Based on Activity Theory

    ERIC Educational Resources Information Center

    Méndez, Laura; Lacasa, Pilar

    2015-01-01

    Introduction: The purpose of this study is to provide a framework for analysis from which to interpret the transformations that take place, as perceived by the participants, when commercial video games are used in the classroom. We will show how Activity Theory (AT) is able to explain and interpret these changes. Method: Case studies are…

  19. Cortical Bases of Speech Perception: Evidence from Functional Lesion Studies

    ERIC Educational Resources Information Center

    Boatman, Dana

    2004-01-01

    Functional lesion studies have yielded new information about the cortical organization of speech perception in the human brain. We will review a number of recent findings, focusing on studies of speech perception that use the techniques of electrocortical mapping by cortical stimulation and hemispheric anesthetization by intracarotid amobarbital.…

  20. Biosensors for EVA: Improved Instrumentation for Ground-based Studies

    NASA Technical Reports Server (NTRS)

    Soller, B.; Ellerby, G.; Zou, F.; Scott, P.; Jin, C.; Lee, S. M. C.; Coates, J.

    2010-01-01

    During lunar excursions in the EVA suit, real-time measurement of metabolic rate is required to manage consumables and guide activities to ensure safe return to the base. Metabolic rate, or oxygen consumption (VO2), is normally measured from pulmonary parameters but cannot be determined with standard techniques in the oxygen-rich environment of a spacesuit. Our group has developed novel near infrared spectroscopic (NIRS) methods to calculate muscle oxygen saturation (SmO 2), hematocrit, and pH, and we recently demonstrated that we can use our NIRS sensor to measure VO 2 on the leg during cycling. Our NSBRI project has 4 objectives: (1) increase the accuracy of the metabolic rate calculation through improved prediction of stroke volume; (2) investigate the relative contributions of calf and thigh oxygen consumption to metabolic rate calculation for walking and running; (3) demonstrate that the NIRS-based noninvasive metabolic rate methodology is sensitive enough to detect decrement in VO 2 in a space analog; and (4) improve instrumentation to allow testing within a spacesuit. Over the past year we have made progress on all four objectives, but the most significant progress was made in improving the instrumentation. The NIRS system currently in use at JSC is based on fiber optics technology. Optical fiber bundles are used to deliver light from a light source in the monitor to the patient, and light reflected back from the patient s muscle to the monitor for spectroscopic analysis. The fiber optic cables are large and fragile, and there is no way to get them in and out of the test spacesuit used for ground-based studies. With complimentary funding from the US Army, we undertook a complete redesign of the sensor and control electronics to build a novel system small enough to be used within the spacesuit and portable enough to be used by a combat medic. In the new system the filament lamp used in the fiber optic system was replaced with a novel broadband near infrared

  1. [Study on atmospheric VOCs in Gongga Mountain base station].

    PubMed

    Zhang, Jun-Ke; Wang, Yue-Si; Wu, Fang-Kun; Sun, Jie

    2012-12-01

    Volatile organic compounds (VOCs) play important roles in the atmosphere as precursors of secondary air pollutants. The regional background concentrations and variation characteristics of VOCs in the atmosphere of southwestern China were studied. Meanwhile, a receptor model based on principal component analysis (PCA) was used to identify the major sources of VOCs. Weekly samples were collected in 2007 in the Gongga Mountain base station and analyzed with a three-stage preconcentration method coupled with GC-MS. The annual mean concentration of TVOCs and NMHCs were 9.40 x 10(-9) +/- 4.55 x 10(-9) and 7.73 x 10(-9) +/- 4.43 x 10(-9), respectively. Aromatic hydrocarbons provided the largest contribution to TVOCs (37.3%), follow by alkanes (30.0%) and halogenated hydrocarbons (19.8%), the smallest contribution was from alkenes (12.9%). Three major sources were resolved by the receptor model, traffic sources, biogenic sources and combustion sources. The seasonal variation of TVOCs in this area was obviously, and the order was autumn > winter > spring > summer. TVOCs concentration in autumn was very significantly higher than that in summer (P < 0.01). The seasonal variation of the four types of VOCs showed different characteristics due to the differences in photochemical properties. Isoprene emissions were from biogenic sources. Regression analysis revealed a good exponential relationship between the isoprene concentration and temperature. High temperatures increased the isoprene concentrations. However, the isoprene concentration remained constant when the ambient air temperature was below 20 degrees C. The TVOCs in Gongga Mountain were at a medium level comparing with the results of other regions, and there was a clear background station emission characteristic. PMID:23379137

  2. Study of cell secretion using MEMS-based arrays

    NASA Astrophysics Data System (ADS)

    Feng, Xiaojun; Szaro, Ben G.; Castracane, James

    2004-01-01

    This paper focuses on the development of a custom MEMS-based array which will facilitate cell secretion studies by enabling parallel electrochemical detection of secretion events from separate cells with millisecond resolution. Initial prototypes of the microarrays have been fabricated with well-shaped gold electrodes which roughly conform to the shape of a single cell. Amperometric measurements on bovine adrenal chromaffin cells using the prototype microarrays concluded that 80% of the catecholamine secreted from the cells was captured by the well-electrodes. This was a 4-fold increase in detection efficiency over the conventional carbon fiber electrode method. To expand the applicability of this method, additional cell-lines and microarray designs are under investigation. An amphibian fibroblast cell-line (FT cell-line, American Tissue Culture Collection) is being used in our lab. FT cells can take up hormones or other biological compounds from the culture media through a non-specific uptake mechanism which is still under investigation. Microarrays of a new design have been fabricated with patterned gold electrodes on polyimide. A different testing method will be applied to these new microarrays. The FT cells will be cultured directly on top of the microarrays to cover the gold electrodes. Cells will then be loaded with norepinephrine by incubation in media containing 1mM norepinephrine. Rapid elevation of intracellular Ca2+ levels triggers the exocytosis of norepinephrine which then can be detected by the gold electrode. The new polyimide based microarrays have been successfully used to support confluent growth of the FT cells. Loading of the FT cells with norepinephrine and electrochemical detection tests are underway.

  3. Study of cell secretion using MEMS-based arrays

    NASA Astrophysics Data System (ADS)

    Feng, Xiaojun; Szaro, Ben G.; Castracane, James

    2003-12-01

    This paper focuses on the development of a custom MEMS-based array which will facilitate cell secretion studies by enabling parallel electrochemical detection of secretion events from separate cells with millisecond resolution. Initial prototypes of the microarrays have been fabricated with well-shaped gold electrodes which roughly conform to the shape of a single cell. Amperometric measurements on bovine adrenal chromaffin cells using the prototype microarrays concluded that 80% of the catecholamine secreted from the cells was captured by the well-electrodes. This was a 4-fold increase in detection efficiency over the conventional carbon fiber electrode method. To expand the applicability of this method, additional cell-lines and microarray designs are under investigation. An amphibian fibroblast cell-line (FT cell-line, American Tissue Culture Collection) is being used in our lab. FT cells can take up hormones or other biological compounds from the culture media through a non-specific uptake mechanism which is still under investigation. Microarrays of a new design have been fabricated with patterned gold electrodes on polyimide. A different testing method will be applied to these new microarrays. The FT cells will be cultured directly on top of the microarrays to cover the gold electrodes. Cells will then be loaded with norepinephrine by incubation in media containing 1mM norepinephrine. Rapid elevation of intracellular Ca2+ levels triggers the exocytosis of norepinephrine which then can be detected by the gold electrode. The new polyimide based microarrays have been successfully used to support confluent growth of the FT cells. Loading of the FT cells with norepinephrine and electrochemical detection tests are underway.

  4. Probabilistic Study Conducted on Sensor-Based Engine Life Calculation

    NASA Technical Reports Server (NTRS)

    Guo, Ten-Huei

    2004-01-01

    Turbine engine life management is a very complicated process to ensure the safe operation of an engine subjected to complex usage. The challenge of life management is to find a reasonable compromise between the safe operation and the maximum usage of critical parts to reduce maintenance costs. The commonly used "cycle count" approach does not take the engine operation conditions into account, and it oversimplifies the calculation of the life usage. Because of the shortcomings, many engine components are regularly pulled for maintenance before their usable life is over. And, if an engine has been running regularly under more severe conditions, components might not be taken out of service before they exceed their designed risk of failure. The NASA Glenn Research Center and its industrial and academic partners have been using measurable parameters to improve engine life estimation. This study was based on the Monte Carlo simulation of 5000 typical flights under various operating conditions. First a closed-loop engine model was developed to simulate the engine operation across the mission profile and a thermomechanical fatigue (TMF) damage model was used to calculate the actual damage during takeoff, where the maximum TMF accumulates. Next, a Weibull distribution was used to estimate the implied probability of failure for a given accumulated cycle count. Monte Carlo simulations were then employed to find the profiles of the TMF damage under different operating assumptions including parameter uncertainties. Finally, probabilities of failure for different operating conditions were analyzed to demonstrate the importance of a sensor-based damage calculation in order to better manage the risk of failure and on-wing life.

  5. Structural studies of enzyme-based microfluidic biofuel cells

    NASA Astrophysics Data System (ADS)

    Togo, Makoto; Takamura, Akimasa; Asai, Tatsuya; Kaji, Hirokazu; Nishizawa, Matsuhiko

    An enzyme-based glucose/O 2 biofuel cell was constructed within a microfluidic channel to study the influence of electrode configuration and fluidic channel height on cell performance. The cell was composed of a bilirubin oxidase (BOD)-adsorbed O 2 cathode and a glucose anode prepared by co-immobilization of glucose dehydrogenase (GDH), diaphorase (Dp) and VK 3-pendant poly- L-lysine. The consumption of O 2 at the upstream cathode protected the downstream anode from interfering O 2 molecules, and consequently improved the cell performance (maximum cell current) ca. 10% for the present cell. The cell performance was also affected by the channel height. The output current and power of a 0.1 mm-height cell was significantly less than those of a 1 mm-height cell because of the depletion of O 2, as determined by the shape of the E- I curve at the cathode. On the other hand, the volume density of current and power was several times higher for the narrower cell.

  6. Satellite-Based Study of Glaciers Retreat in Northern Pakistan

    NASA Astrophysics Data System (ADS)

    Munir, Siraj

    Glaciers serve as a natural regulator of regional water supplies. About 16933 Km 2 area of glaciers is covered by Pakistan. These glaciers are enormous reservoirs of fresh water and their meltwater is an important resource which feed rivers in Pakistan. Glacier depletion, especially recent melting can affect agriculture, drinking water supplies, hydro-electric power, and ecological habitats. This can also have a more immediate impact on Pakistan's economy that depends mainly on water from glacier melt. Melting of seasonal snowfall and permanent glaciers has resulted not only in reduction of water resources but also caused flash floods in many areas of Pakistan. With the advent of satellite technology, using optical and SAR data the study of glaciers, has become possible. Using temporal data, based on calculation of snow index, band ratios and texture reflectance it has been revealed that the rate of glacier melting has increased as a consequent of global warming. Comparison of Landsat images of Batura glacier for October 1992 and October 2000 has revealed that there is a decrease of about 17 sq km in Batura glaciers. Although accurate changes in glacier extent cannot be assessed without baseline information, these efforts have been made to analyze future changes in glaciated area.

  7. Theoretical study of impurity effects in iron-based superconductors

    NASA Astrophysics Data System (ADS)

    Navarro Gastiasoro, Maria; Hirschfeld, Peter; Andersen, Brian

    2013-03-01

    Several open questions remain unanswered for the iron-based superconductors (FeSC), including the importance of electronic correlations and the symmetry of the superconducting order parameter. Motivated by recent STM experiments which show a fascinating variety of resonant defect states in FeSC, we adopt a realistic five-band model including electronic Coulomb correlations to study local effects of disorder in the FeSC. In order to minimize the number of free parameters, we use the pairing interactions obtained from spin-fluctuation exchange to determine the homogeneous superconducting state. The ability of local impurity potentials to induce resonant states depends on their scattering strength Vimp; in addition, for appropriate Vimp, such states are associated with local orbital- and magnetic order. We investigate the density of states near such impurities and show how tunneling experiments may be used to probe local induced order. In the SDW phase, we show how C2 symmetry-breaking dimers are naturally formed around impurities which also form cigar-like (pi,pi) structures embedded in the (pi,0) magnetic bulk phase. Such electronic dimers have been shown to be candidates for explaining the so-called nematogens observed previously by QPI in Co-doped CaFe2As2.

  8. Microbiota-based Signature of Gingivitis Treatments: A Randomized Study

    PubMed Central

    Huang, Shi; Li, Zhen; He, Tao; Bo, Cunpei; Chang, Jinlan; Li, Lin; He, Yanyan; Liu, Jiquan; Charbonneau, Duane; Li, Rui; Xu, Jian

    2016-01-01

    Plaque-induced gingivitis can be alleviated by various treatment regimens. To probe the impacts of various anti-gingivitis treatments on plaque microflora, here a double blinded, randomized controlled trial of 91 adults with moderate gingivitis was designed with two anti-gingivitis regimens: the brush-alone treatment and the brush-plus-rinse treatment. In the later group, more reduction in both Plaque Index (TMQHI) and Gingival Index (mean MGI) at Day 3, Day 11 and Day 27 was evident, and more dramatic changes were found between baseline and other time points for both supragingival plaque microbiota structure and salivary metabonomic profiles. A comparison of plaque microbiota changes was also performed between these two treatments and a third dataset where 50 subjects received regimen of dental scaling. Only Actinobaculum, TM7 and Leptotrichia were consistently reduced by all the three treatments, whereas the different microbial signatures of the three treatments during gingivitis relieve indicate distinct mechanisms of action. Our study suggests that microbiota based signatures can serve as a valuable approach for understanding and potentially comparing the modes of action for clinical treatments and oral-care products in the future. PMID:27094556

  9. Neutrino-nucleus reactions based on recent structure studies

    SciTech Connect

    Suzuki, Toshio

    2015-05-15

    Neutrino-nucleus reactions are studied with the use of new shell model Hamiltonians, which have proper tensor components in the interactions and prove to be successful in the description of Gamow-Teller (GT) strengths in nuclei. The new Hamiltonians are applied to obtain new neutrino-nucleus reaction cross sections in {sup 12}C, {sup 13}C, {sup 56}Fe and {sup 56}Ni induced by solar and supernova neutrinos. The element synthesis by neutrino processes in supernova explosions is discussed with the new cross sections. The enhancement of the production yields of {sup 7}Li, {sup 11}B and {sup 55}Mn is obtained while fragmented GT strength in {sup 56}Ni with two-peak structure is found to result in smaller e-capture rates at stellar environments. The monopole-based universal interaction with tensor force of π+ρ meson exchanges is used to evaluate GT strength in {sup 40}Ar and ν-induced reactions on {sup 40}Ar. It is found to reproduce well the experimental GT strength in {sup 40}Ar.

  10. A Diatom-based, Paleolimnological Study Of Rush Lake, Wisconsin

    NASA Astrophysics Data System (ADS)

    Fischer-Guex, L.; Pillsbury, R. W.; Mode, W.

    2005-05-01

    Rush Lake, located in Winnebago County, Wisconsin, is a shallow, eutrophic, lake/wetland dominated by cattails. This system has historically been important for fishing and waterfowl production. But recently the general public view the lake as degraded from increased sedimentation, contamination from lead shot, and perceived reduction in fish and wildlife. A sediment core (374cm) was taken by employing a modified Livingstone piston corer. The core sample was dated with carbon-14 yielding a date at the base of the core of 4110 +/- 40 yr. B.P. The core sediments were sampled for diatoms starting at 5cm for every 10cm after that (37 samples). Diatoms were counted for a total of 300 per sample. Typical of shallow lakes, the core showed signs of being extensively reworked. Despite this, multivariate analysis of diatoms (PCA) suggests that this system has become more eutrophic. This is consistent with a pollen analysis and is likely due to agricultural activities in the watershed. There is no evidence (i.e., increase in % planktonic diatoms) that the lake had ever developed a pelagic zone for an extended period of time. Results of this study may be useful in making future management decisions to restore Rush Lake.

  11. Microbiota-based Signature of Gingivitis Treatments: A Randomized Study.

    PubMed

    Huang, Shi; Li, Zhen; He, Tao; Bo, Cunpei; Chang, Jinlan; Li, Lin; He, Yanyan; Liu, Jiquan; Charbonneau, Duane; Li, Rui; Xu, Jian

    2016-01-01

    Plaque-induced gingivitis can be alleviated by various treatment regimens. To probe the impacts of various anti-gingivitis treatments on plaque microflora, here a double blinded, randomized controlled trial of 91 adults with moderate gingivitis was designed with two anti-gingivitis regimens: the brush-alone treatment and the brush-plus-rinse treatment. In the later group, more reduction in both Plaque Index (TMQHI) and Gingival Index (mean MGI) at Day 3, Day 11 and Day 27 was evident, and more dramatic changes were found between baseline and other time points for both supragingival plaque microbiota structure and salivary metabonomic profiles. A comparison of plaque microbiota changes was also performed between these two treatments and a third dataset where 50 subjects received regimen of dental scaling. Only Actinobaculum, TM7 and Leptotrichia were consistently reduced by all the three treatments, whereas the different microbial signatures of the three treatments during gingivitis relieve indicate distinct mechanisms of action. Our study suggests that microbiota based signatures can serve as a valuable approach for understanding and potentially comparing the modes of action for clinical treatments and oral-care products in the future. PMID:27094556

  12. Electrochemical studies of calcium chloride-based molten salt systems

    SciTech Connect

    Blanchard, T.P. Jr.

    1992-12-01

    Conductance and EMF studies of CaCl{sub 2}-based melts were performed in the temperature range 790--990 C. Conductivity data collected using magnesia tubes and capillaries showed deviations from the data recommended by the National Bureau of Standards. These deviations are attributed to the slow dissolution of magnesia by the CaCl{sub 2}-CaO melt. Conductivity data for molten CaCl{sub 2} using a pyrolytic boron nitride capillary were in reasonable agreement with the recommended data; however, undissolved CaO in CaCl{sub 2} may have caused blockage of the pyrolytic boron nitride capillary, resulting in fluctuations in the measured resistance. The utility of the AgCl/Ag reference electrode in CaCl{sub 2}-AgCl and CaCl{sub 2}-CaO-AgCl melts, using asbestos diaphragms and Vycor glass as reference half-cell membranes, was also investigated. Nernstian behavior was observed using both types of reference half-cell membranes in CaCl{sub 2}-AgCl melts. The AgCl/Ag reference electrode also exhibited Nernstian behavior in CaCl{sub 2}-CaO-AgCl melts using a Vycor reference half-cell membrane and a magnesia crucible. The use of CaCl{sub 2} as a solvent is of interest since it is used in plutonium metal purification, as well as various other commercial applications. 97 refs., 33 figs., 13 tabs.

  13. Rehabilitation regimes based upon psychophysical studies of prosthetic vision

    NASA Astrophysics Data System (ADS)

    Chen, S. C.; Suaning, G. J.; Morley, J. W.; Lovell, N. H.

    2009-06-01

    Human trials of prototype visual prostheses have successfully elicited visual percepts (phosphenes) in the visual field of implant recipients blinded through retinitis pigmentosa and age-related macular degeneration. Researchers are progressing rapidly towards a device that utilizes individual phosphenes as the elementary building blocks to compose a visual scene. This form of prosthetic vision is expected, in the near term, to have low resolution, large inter-phosphene gaps, distorted spatial distribution of phosphenes, restricted field of view, an eccentrically located phosphene field and limited number of expressible luminance levels. In order to fully realize the potential of these devices, there needs to be a training and rehabilitation program which aims to assist the prosthesis recipients to understand what they are seeing, and also to adapt their viewing habits to optimize the performance of the device. Based on the literature of psychophysical studies in simulated and real prosthetic vision, this paper proposes a comprehensive, theoretical training regime for a prosthesis recipient: visual search, visual acuity, reading, face/object recognition, hand-eye coordination and navigation. The aim of these tasks is to train the recipients to conduct visual scanning, eccentric viewing and reading, discerning low-contrast visual information, and coordinating bodily actions for visual-guided tasks under prosthetic vision. These skills have been identified as playing an important role in making prosthetic vision functional for the daily activities of their recipients.

  14. Study on upper limb rehabilitation system based on surface EMG.

    PubMed

    Wang, Lan; Li, Hailong; Wang, Zhengyu; Meng, Fandong

    2015-01-01

    During the rehabilitation process, it is essential to accurately judge a patient's recovery in a timely manner. A reasonable and matched training program is significant in the development of rehabilitation system. This paper presents a new upper limb rehabilitation training system, which consists of an upper limb rehabilitation training device, a current detection circuit, a motor speed test circuit, a surface EMG (sEMG) sensor, and a dSPACE HIL simulation platform. The real-time output torque of the servo motor is calculated by using the motor's real-time current and speed, in order to monitor the patient's training situation. The signal of sEMG is collected in real time and is processed with root mean square (RMS) to characterize the degree of muscle activation. Based on this rehabilitation system, maximum voluntary contraction (MVC) experiments, passive training experiments under different speeds, and active training experiments under different damping are studied. The results show that this new system performs real-time and accurate monitoring of a patient's training situation. It can also assess a patient's recovery through muscle activation. To a certain extent, this system provides a platform for research and development of rehabilitation medical engineering. PMID:26406076

  15. Exploring Global Change In Place-Based Case Studies

    NASA Astrophysics Data System (ADS)

    Moosavi, S. C.

    2011-12-01

    The complexity of global climate change makes the subject challenging for the average student, particularly given the nuanced feedbacks and exceptions to the general "warming" or "drying" trend that may be experienced at the local and regional level at which most people experience geologic processes. Geoscience educators can reduce these barriers and draw in student learners by adopting a place-based approach to teaching and researching geologic principles that relate to global change. Assisting students in recognizing and understanding the geologic environment in which they live and study has the side benefit of making the potential effect of climate change tangible. This presentation will review several approaches for using place-based case studies to explore global climate change issues in large lecture, small seminar, field research and service learning environments. The special place project used in large introductory physical geology courses requires each student to select a place familiar and unique to them for an in depth study of the common course content as the semester progresses. Students are specifically tasked with identifying how their site came to be, the geologic processes that act upon it today, how the site may have been different during the last glacial advance and how global climate change (specifically warming of 3OC over 50 years) might impact the site. The concept that change has occurred at the student's site in the past, even far from glacial environments, opens students to the scale of potential anthropogenic climate change. A freshman seminar Global Warming & Climate Change - Service in Preparation for Climate Change: The Second Battle of New Orleans focused on the environmental threats to New Orleans and southeastern Louisiana resulting from regional land use decisions in the centuries before Hurricane Katrina, and the threat that global change relating to sea level rise, acceleration of the hydrologic cycle and intensification of

  16. Agent-Based vs. Equation-based Epidemiological Models:A Model Selection Case Study

    SciTech Connect

    Sukumar, Sreenivas R; Nutaro, James J

    2012-01-01

    This paper is motivated by the need to design model validation strategies for epidemiological disease-spread models. We consider both agent-based and equation-based models of pandemic disease spread and study the nuances and complexities one has to consider from the perspective of model validation. For this purpose, we instantiate an equation based model and an agent based model of the 1918 Spanish flu and we leverage data published in the literature for our case- study. We present our observations from the perspective of each implementation and discuss the application of model-selection criteria to compare the risk in choosing one modeling paradigm to another. We conclude with a discussion of our experience and document future ideas for a model validation framework.

  17. Hooking the Geographer in Children with Field-Based Studies

    ERIC Educational Resources Information Center

    Krall, Florence; And Others

    1978-01-01

    Suggests projects to help elementary students learn about man-land relationships through field experience, inquiry techniques, and a thematic, interdisciplinary approach. Children study a natural community, a human community, solid wastes, and energy conservation. (Author/AV)

  18. COMSOL-based Nuclear Reactor Kinetics Studies at the HFIR

    SciTech Connect

    Chandler, David; Freels, James D; Maldonado, G Ivan; Primm, Trent

    2011-01-01

    The computational ability to accurately predict the dynamic behavior of a nuclear reactor core in response to reactivity-induced perturbations is an important subject in reactor physics. Space-time and point kinetics methodologies were developed for the purpose of studying the transient-induced behavior of the High Flux Isotope Reactor s (HFIR) compact core. The space-time simulations employed the three-energy-group neutron diffusion equations, and transients initiated by control cylinder and hydraulic tube rabbit ejections were studied. The work presented here is the first step towards creating a comprehensive multiphysics methodology for studying the dynamic behavior of the HFIR core during reactivity perturbations. The results of these studies show that point kinetics is adequate for small perturbations in which the power distribution is assumed to be time-independent, but space-time methods must be utilized to determine localized effects.

  19. Integrated Genome-Based Studies of Shewanella Ecophysiology

    SciTech Connect

    Zhou, Jizhong; He, Zhili

    2014-04-08

    As a part of the Shewanella Federation project, we have used integrated genomic, proteomic and computational technologies to study various aspects of energy metabolism of two Shewanella strains from a systems-level perspective.

  20. Aeroelastic Optimization Study Based on X-56A Model

    NASA Technical Reports Server (NTRS)

    Li, Wesley; Pak, Chan-Gi

    2014-01-01

    A design process which incorporates the object-oriented multidisciplinary design, analysis, and optimization (MDAO) tool and the aeroelastic effects of high fidelity finite element models to characterize the design space was successfully developed and established. Two multidisciplinary design optimization studies using an object-oriented MDAO tool developed at NASA Armstrong Flight Research Center were presented. The first study demonstrates the use of aeroelastic tailoring concepts to minimize the structural weight while meeting the design requirements including strength, buckling, and flutter. A hybrid and discretization optimization approach was implemented to improve accuracy and computational efficiency of a global optimization algorithm. The second study presents a flutter mass balancing optimization study. The results provide guidance to modify the fabricated flexible wing design and move the design flutter speeds back into the flight envelope so that the original objective of X-56A flight test can be accomplished.

  1. Familial risk of cerebral palsy: population based cohort study

    PubMed Central

    Wilcox, Allen J; Lie, Rolv T; Moster, Dag

    2014-01-01

    Objective To investigate risks of recurrence of cerebral palsy in family members with various degrees of relatedness to elucidate patterns of hereditability. Design Population based cohort study. Setting Data from the Medical Birth Registry of Norway, linked to the Norwegian social insurance scheme to identify cases of cerebral palsy and to databases of Statistics Norway to identify relatives. Participants 2 036 741 Norwegians born during 1967-2002, 3649 of whom had a diagnosis of cerebral palsy; 22 558 pairs of twins, 1 851 144 pairs of first degree relatives, 1 699 856 pairs of second degree relatives, and 5 165 968 pairs of third degree relatives were identified. Main outcome measure Cerebral palsy. Results If one twin had cerebral palsy, the relative risk of recurrence of cerebral palsy was 15.6 (95% confidence interval 9.8 to 25) in the other twin. In families with an affected singleton child, risk was increased 9.2 (6.4 to 13)-fold in a subsequent full sibling and 3.0 (1.1 to 8.6)-fold in a half sibling. Affected parents were also at increased risk of having an affected child (6.5 (1.6 to 26)-fold). No evidence was found of differential transmission through mothers or fathers, although the study had limited power to detect such differences. For people with an affected first cousin, only weak evidence existed for an increased risk (1.5 (0.9 to 2.7)-fold). Risks in siblings or cousins were independent of sex of the index case. After exclusion of preterm births (an important risk factor for cerebral palsy), familial risks remained and were often stronger. Conclusions People born into families in which someone already has cerebral palsy are themselves at elevated risk, depending on their degree of relatedness. Elevated risk may extend even to third degree relatives (first cousins). The patterns of risk suggest multifactorial inheritance, in which multiple genes interact with each other and with environmental factors. These data offer additional

  2. Mortality in Autism: A Prospective Longitudinal Community-Based Study

    ERIC Educational Resources Information Center

    Gillberg, Christopher; Billstedt, Eva; Sundh, Valter; Gillberg, I. Carina

    2010-01-01

    The purposes of the present study were to establish the mortality rate in a representative group of individuals (n = 120) born in the years 1962-1984, diagnosed with autism/atypical autism in childhood and followed up at young adult age (greater than or equal to 18 years of age), and examine the risk factors and causes of death. The study group,…

  3. Planned earth-based studies of the phobos material

    NASA Astrophysics Data System (ADS)

    Galimov, E. M.; Kostitsyn, Yu. A.

    2012-12-01

    The article describes scientific challenges in the analysis of the Phobos material that is to be returned in the Russian Phobos-Grunt space mission. Their close connection with current problems in studies of the Earth and the origin of life has been demonstrated. The most obvious up-to-date studies that are to be carried out under laboratory conditions after the soil sample is delivered to Earth are specified, and the required equipment listed.

  4. Low energy cosmic ray studies from a lunar base

    NASA Technical Reports Server (NTRS)

    Wiedenbeck, Mark E.

    1990-01-01

    Studies of cosmic ray nuclei with energies less than about 7 GeV/nucleon in low earth orbit are hampered by the geomagnetic field. Even in high inclination orbits these effects can be significant. The lunar surface (or lunar orbit) provides an attractive site for carrying out low energy cosmic ray studies which require large detectors. The rationale and requirements for this type of experiment are described.

  5. Studies of Template-based Photometric Classification of Supernovae

    NASA Astrophysics Data System (ADS)

    Asimacopoulos, Leia; Londo, Stephen; Macaluso, Joseph; Cunningham, John; Kuhlmann, Steve; Kovacs, Eve

    2016-01-01

    We study photometric classification of Type Ia (SNIa) and core collapse (SNcc) supernovae using a combination of simulated data from DES and real data from SDSS. We increase the number of core collapse templates from the eight commonly used to type SDSS supernovae (PSNID) to forty-five currently available in SNANA. These are implemented in the SNCosmo analysis package. Our goal is to study the accuracy in identifying all types of supernovae as a function of numbers and types of templates.

  6. Recurrent Wheezing in Infants: A Population-Based Study.

    PubMed

    Belhassen, Manon; De Blic, Jacques; Laforest, Laurent; Laigle, Valérie; Chanut-Vogel, Céline; Lamezec, Liliane; Brouard, Jacques; Fauroux, Brigitte; de Pouvourville, Gérard; Ginoux, Marine; Van Ganse, Eric

    2016-04-01

    Recurrent wheezing (RW) has a significant impact on infants, caregivers, and society, but morbidity and related medical resource utilization (MRU) have not been thoroughly explored. The burden of RW needs to be documented with population-based data. The objective was to assess the characteristics, medical management, and MRU of RW infants identified from national claims data.Infants aged from 6 to 24 months, receiving ≥2 dispensations of respiratory drugs within 3 months, and presenting a marker of poor control (index date), were selected. During the 6 months after index date, MRU was described in the cohort and among 3 subgroups with more severe RW, defined as ≥4 dispensations of respiratory drugs, ≥3 dispensations of oral corticosteroids (OCS), or ≥1 hospitalization for respiratory symptoms.A total of 115,489 infants had RW, corresponding to 8.2% of subjects in this age group. During follow-up, 68.7% of infants received inhaled corticosteroids, but only 1.8 U (unit) were dispensed over 6 months, suggesting discontinuous use. Control was mostly inadequate: 61.7% of subjects received OCS, 80.2% antibiotics, and 71.2% short-acting beta-agonists, and medical/paramedical visits were numerous, particularly for physiotherapy. Severe RW concerned 39.0% of the cohort; 32.8% and 11.7% of infants had repeated use of respiratory drugs and OCS, respectively, and 5.5% were hospitalized for respiratory symptoms.In this real-life nation-wide study, RW was common and infants had poor control and high MRU. Interventions are needed to support adequate use of controller therapy, and to improve medical care. PMID:27082618

  7. Parametric Study Conducted of Rocket- Based, Combined-Cycle Nozzles

    NASA Technical Reports Server (NTRS)

    Steffen, Christopher J., Jr.; Smith, Timothy D.

    1998-01-01

    Having reached the end of the 20th century, our society is quite familiar with the many benefits of recycling and reusing the products of civilization. The high-technology world of aerospace vehicle design is no exception. Because of the many potential economic benefits of reusable launch vehicles, NASA is aggressively pursuing this technology on several fronts. One of the most promising technologies receiving renewed attention is Rocket-Based, Combined-Cycle (RBCC) propulsion. This propulsion method combines many of the efficiencies of high-performance jet aircraft with the power and high-altitude capability of rocket engines. The goal of the present work at the NASA Lewis Research Center is to further understand the complex fluid physics within RBCC engines that govern system performance. This work is being performed in support of NASA's Advanced Reusable Technologies program. A robust RBCC engine design optimization demands further investigation of the subsystem performance of the engine's complex propulsion cycles. The RBCC propulsion system under consideration at Lewis is defined by four modes of operation in a singlestage- to-orbit configuration. In the first mode, the engine functions as a rocket-driven ejector. When the rocket engine is switched off, subsonic combustion (mode 2) is present in the ramjet mode. As the vehicle continues to accelerate, supersonic combustion (mode 3) occurs in the ramjet mode. Finally, as the edge of the atmosphere is approached and the engine inlet is closed off, the rocket is reignited and the final accent to orbit is undertaken in an all-rocket mode (mode 4). The performance of this fourth and final mode is the subject of this present study. Performance is being monitored in terms of the amount of thrust generated from a given amount of propellant.

  8. Solderability Study of RABiTS-Based YBCO Coated Conductors

    SciTech Connect

    Zhang, Yifei; Duckworth, Robert C; Ha, Tam T; Gouge, Michael J

    2011-01-01

    The solderability of commercially available YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) coated conductors that were made from Rolling Assisted Biaxially Textured Substrates (RABiTS)-based templates was studied. The coated conductors, also known as second-generation (2G) high temperature superconductor (HTS) wires (in the geometry of flat tapes about 4 mm wide), were laminated with copper, brass, or stainless steel strips as stabilizers. To understand the factors that influence their solderability, surface profilometry and scanning electron microscopy were used to characterize the wire surfaces. The solderability of three solders, 52In48Sn, 67Bi33In, and 100In (wt.%), was evaluated using a standard test (IPC/ECA J-STD-002) and with two different commercial fluxes. It was found that the solderability varied with the solder and flux but the three different wires showed similar solderability for a fixed combination of solder and flux. Solder joints of the 2G wires were fabricated using the tools and the procedures recommended by the HTS wire manufacturer. The solder joints were made in a lap-joint geometry and with the superconducting sides of the two wires face-to-face. The electrical resistances of the solder joints were measured at 77 K, and the results were analyzed to qualify the soldering materials and evaluate the soldering process. It was concluded that although the selection of soldering materials affected the resistance of a solder joint, the resistivity of the stabilizer was the dominant factor.

  9. A School-Based Study on Situational Interest of Investigative Study in Senior Physics

    ERIC Educational Resources Information Center

    Leung, Yat-yin

    2015-01-01

    This paper reports the findings from the interview data of a research aiming at studying how to trigger students' situational interest in physics and its implications on learning and teaching in the New Senior Secondary (NSS) physics curriculum. 49 students from a boys' school were invited to write one to three learning experiences in physics that…

  10. Aeroelastic Optimization Study Based on the X-56A Model

    NASA Technical Reports Server (NTRS)

    Li, Wesley W.; Pak, Chan-Gi

    2014-01-01

    One way to increase the aircraft fuel efficiency is to reduce structural weight while maintaining adequate structural airworthiness, both statically and aeroelastically. A design process which incorporates the object-oriented multidisciplinary design, analysis, and optimization (MDAO) tool and the aeroelastic effects of high fidelity finite element models to characterize the design space was successfully developed and established. This paper presents two multidisciplinary design optimization studies using an object-oriented MDAO tool developed at NASA Armstrong Flight Research Center. The first study demonstrates the use of aeroelastic tailoring concepts to minimize the structural weight while meeting the design requirements including strength, buckling, and flutter. Such an approach exploits the anisotropic capabilities of the fiber composite materials chosen for this analytical exercise with ply stacking sequence. A hybrid and discretization optimization approach improves accuracy and computational efficiency of a global optimization algorithm. The second study presents a flutter mass balancing optimization study for the fabricated flexible wing of the X-56A model since a desired flutter speed band is required for the active flutter suppression demonstration during flight testing. The results of the second study provide guidance to modify the wing design and move the design flutter speeds back into the flight envelope so that the original objective of X-56A flight test can be accomplished successfully. The second case also demonstrates that the object-oriented MDAO tool can handle multiple analytical configurations in a single optimization run.

  11. A study on the cytotoxicity of carbon-based materials.

    PubMed

    Saha, Dipendu; Heldt, Caryn L; Gencoglu, Maria F; Vijayaragavan, K Saagar; Chen, Jihua; Saksule, Ashish

    2016-11-01

    With an aim to understand the origin and key contributing factors towards carbon-induced cytotoxicity, we have studied five different carbon samples with diverse surface area, pore width, shape and size, conductivity and surface functionality. All the carbon materials were characterized with surface area and pore size distribution, X-ray photoelectron spectroscopy (XPS) and electron microscopic imaging. We performed cytotoxicity study in Caco-2 cells by colorimetric assay, oxidative stress analysis by reactive oxygen species (ROS) detection, cellular metabolic activity measurement by adenosine triphosphate (ATP) depletion and visualization of cellular internalization by TEM imaging. The carbon materials demonstrated a varying degree of cytotoxicity in contact with Caco-2 cells. The lowest cell survival rate was observed for nanographene, which possessed the minimal size amongst all the carbon samples under this study. None of the carbons induced oxidative stress to the cells as indicated by the ROS generation results. Cellular metabolic activity study revealed that the carbon materials caused ATP depletion in cells and nanographene caused the highest depletion. Visual observation by TEM imaging indicated the cellular internalization of nanographene. This study confirmed that the size is the key cause of carbon-induced cytotoxicity and it is probably caused by the ATP depletion within the cell. PMID:27524001

  12. A Ground-Based Research Vehicle for Base Drag Studies at Subsonic Speeds

    NASA Technical Reports Server (NTRS)

    Diebler, Corey; Smith, Mark

    2002-01-01

    A ground research vehicle (GRV) has been developed to study the base drag on large-scale vehicles at subsonic speeds. Existing models suggest that base drag is dependent upon vehicle forebody drag, and for certain configurations, the total drag of a vehicle can be reduced by increasing its forebody drag. Although these models work well for small projectile shapes, studies have shown that they do not provide accurate predictions when applied to large-scale vehicles. Experiments are underway at the NASA Dryden Flight Research Center to collect data at Reynolds numbers to a maximum of 3 x 10(exp 7), and to formulate a new model for predicting the base drag of trucks, buses, motor homes, reentry vehicles, and other large-scale vehicles. Preliminary tests have shown errors as great as 70 percent compared to Hoerner's two-dimensional base drag prediction. This report describes the GRV and its capabilities, details the studies currently underway at NASA Dryden, and presents preliminary results of both the effort to formulate a new base drag model and the investigation into a method of reducing total drag by manipulating forebody drag.

  13. Experimental and Theoretical Study of Microturbine-Based BCHP System

    SciTech Connect

    Fairchild, P.D.

    2001-07-12

    On-site and near-site distributed power generation (DG), as part of a Buildings Cooling, Heating and Power (BCHP) system, brings both electricity and waste heat from the DG sources closer to the end user's electric and thermal loads. Consequently, the waste heat can be used as input power for heat-activated air conditioners, chillers, and desiccant dehumidification systems; to generate steam for space heating; or to provide hot water for laundry, kitchen, cleaning services and/or rest rooms. By making use of what is normally waste heat, BCHP systems meet a building's electrical and thermal loads with a lower input of fossil fuel, yielding resource efficiencies of 40 to 70% or more. To ensure the success of BCHP systems, interactions of a DG system-such as a microturbine and thermal heat recovery units under steady-state modes of operation with various exhaust back pressures-must be considered. This article studies the performance and emissions of a 30-kW microturbine over a range of design and off-design conditions in steady-state operating mode with various back pressures. In parallel with the experimental part of the project, a BCHP mathematical model was developed describing basic thermodynamic and hydraulic processes in the system, heat and material balances, and the relationship of the balances. to the system configuration. The model can determine the efficiency of energy conversion both for an individual microturbine unit and for the entire BCHP system for various system configurations and external loads. Based on actual data Tom a 30-kW microturbine, linear analysis was used to obtain an analytical relationship between the changes in the thermodynamic and hydraulic parameters of the system. The actual data show that, when the backpressure at the microturbine exhaust outlet is increased to the maximum of 7 in. WC (0.017 atm), the microturbine's useful power output decreases by from 3.5 % at a full power setting of 30 kW to 5.5 % at a one-third power setting

  14. Low temperature rheological studies of hydrocarbon base lubricants

    SciTech Connect

    Venerus, D.C.; Klaus, E.E.; Duda, J.L.

    1987-01-01

    This study is designed to evaluate the rheological properties of samples of waxy mineral oil, a wax-free hydrocarbon solvent, wax-free polymer-thickened oils and fully formulated lubricants containing wax and polymer in hydrocarbon solvents. A mechanical spectrometer (cone and plate rotational viscometer) and the mini rotary viscometer were used in these studies. The cooling rate and cold soak times were computer programmed using a mechanical system. A compromise system using a cooling rate of 0.56/sup 0/C/min and a cold soak time of one hour was used in order to produce data in a reasonable time. These values were chosen from the information gained on wax crystal growth and equilibration from the low temperature dewaxing studies conducted at this laboratory.

  15. Studies of zeolite-based artificial photosynthetic systems

    NASA Astrophysics Data System (ADS)

    Zhang, Haoyu

    Y were obtained. The Ru complexes were anchored on the surface of zeolites via ion-exchange or "ship-in-bottle" synthesis. The spectroscopic properties of the NanoY-entrapped species including methyl viologen (MV2+), RuL were measured via transmission techniques. The zeolite-encapsulated species were found to have red-shift absorption and emission bands and longer MLCT life times. By incorporating both donors Ru complexes and acceptors MV2+ in NanoY, electron transfer kinetics was examined. LFP study showed a slower back-electron-transfer rate as compared to forward electron transfer. Photochemically generated long-lived charge separation is the key step in processes that aim for conversion of solar energy into chemical energy. We incorporated RuL complex on the surface of a pinhole-free zeolite membrane by quaternization of L and surrounded with intrazeolitic bipyridinium ions (N,N'-trimethyl-2,2'-bipyridinium ion, 3DQ2+). Visible-light irradiation of the Ru complex side of the membrane in the presence of a sacrificial electron donor led to formation of PVS-· on the other side. Pore-blocking disilazane-based chemistry allows for Na+ to migrate through the membrane to maintain charge balance, while keeping the 3DQ2+ entrapped in the zeolite. These results provided encouragement that the zeolite membrane based architecture has the necessary features for not only incorporating molecular assemblies with long-lived charge separation but also for ready exploitation of the spatially separated charges to store visible light energy in chemical species. The pore-narrowing strategy applied under mild conditions can be used in control-release of active substances such as drug, pesticides, and herbicides. Methyl viologen (MV2+) was chosen as the guest molecule, since it is widely used as an herbicide and its release is of interest in agricultural applications. To explore the controlled-release capability of the surface-modified zeolite, MV2+-encapsulated zeolite Y particles were

  16. INTEGRATED GENOME-BASED STUDIES OF SHEWANELLA ECOPHYSIOLOGY

    SciTech Connect

    NEALSON, KENNETH H.

    2013-10-15

    laboratories. Applications: 1. Corrosion: Electron flow is often part of the corrosive process, and several studies were done in concert with this proposal with regard to the ability of EET-capable bacteria to enhance, inhibit, or detect corrosion. These included using EET-capable bacteria to detect corrosion in its earliest stages [5], to use corrosion-causing bacteria for the study of the microbe/mineral interface during corrosion [1], and to study the groups of microbes involved with corrosion of natural systems [19]. 2. Bioenergy and microbial fuel cells: The production of electricity by Shewanella was shown early in this program (several years ago) to be dependent on the genes for extracellular electron transport (EET), and applied work involved the testing of various strains and conditions for the optimization of current production by the shewanellae [11,14,16]. 3. Identification of shewanellae strains: Based on similarities seen in genomic comparisons, a rapid method was employed for distinguishing between shewanellae strains [17]. Interactions with other laboratories: This grant was an extension of a grant involving the so-called ?Shewanella Federation?, and as such, a number of our publications were joint with other members of this group. The groups included: 1. Pacific Northwest Laboratories ? 2. Oak Ridge National Labs 3. Michigan State University 4. University of Oklahoma 5. Naval Research Laboratory, Washington DC 6. Burnham Medical Research Institute, San Diego 7. J. Craig Venter Institute, San Diego Education: Graduate Students: Michael Waters, Ph.D. ? at NIST, Washington D.C. Lewis Hsu, Ph.D. ? at NRL, San Diego Howard Harris, Ph.D. ? Postdoc at University, France Everett Salas, Ph.D. ? Scientist at Chevron McLean, Jeffrey, Ph.D. ? Scientist at J. Craig Venter Institute McCrow, John, Ph.D. ? Scientist at J. Craig Venter Institute Postdocs: Mohamed El-Naggar ? Professor of Physics, USC Jinjun Kan ? Senior Researcher at Undergraduatges: During this year, we had

  17. Data book: Space station/base food system study. Book 3: Study selection rationale sheets

    NASA Technical Reports Server (NTRS)

    1970-01-01

    The supporting rationale sheets are presented which were utilized in the selection and support of the concepts considered in the final phase of the study. Each concept, conceived to fulfill a specific function of the food system, was assessed in terms of the eight critical factors depicted on the rationale sheet. When weighted and totaled, the resulting selection factor was used as a guide in making the final decision.

  18. Postmarketing Safety Study Tool: A Web Based, Dynamic, and Interoperable System for Postmarketing Drug Surveillance Studies

    PubMed Central

    Sinaci, A. Anil; Laleci Erturkmen, Gokce B.; Gonul, Suat; Yuksel, Mustafa; Invernizzi, Paolo; Thakrar, Bharat; Pacaci, Anil; Cinar, H. Alper; Cicekli, Nihan Kesim

    2015-01-01

    Postmarketing drug surveillance is a crucial aspect of the clinical research activities in pharmacovigilance and pharmacoepidemiology. Successful utilization of available Electronic Health Record (EHR) data can complement and strengthen postmarketing safety studies. In terms of the secondary use of EHRs, access and analysis of patient data across different domains are a critical factor; we address this data interoperability problem between EHR systems and clinical research systems in this paper. We demonstrate that this problem can be solved in an upper level with the use of common data elements in a standardized fashion so that clinical researchers can work with different EHR systems independently of the underlying information model. Postmarketing Safety Study Tool lets the clinical researchers extract data from different EHR systems by designing data collection set schemas through common data elements. The tool interacts with a semantic metadata registry through IHE data element exchange profile. Postmarketing Safety Study Tool and its supporting components have been implemented and deployed on the central data warehouse of the Lombardy region, Italy, which contains anonymized records of about 16 million patients with over 10-year longitudinal data on average. Clinical researchers in Roche validate the tool with real life use cases. PMID:26543873

  19. Postmarketing Safety Study Tool: A Web Based, Dynamic, and Interoperable System for Postmarketing Drug Surveillance Studies.

    PubMed

    Sinaci, A Anil; Laleci Erturkmen, Gokce B; Gonul, Suat; Yuksel, Mustafa; Invernizzi, Paolo; Thakrar, Bharat; Pacaci, Anil; Cinar, H Alper; Cicekli, Nihan Kesim

    2015-01-01

    Postmarketing drug surveillance is a crucial aspect of the clinical research activities in pharmacovigilance and pharmacoepidemiology. Successful utilization of available Electronic Health Record (EHR) data can complement and strengthen postmarketing safety studies. In terms of the secondary use of EHRs, access and analysis of patient data across different domains are a critical factor; we address this data interoperability problem between EHR systems and clinical research systems in this paper. We demonstrate that this problem can be solved in an upper level with the use of common data elements in a standardized fashion so that clinical researchers can work with different EHR systems independently of the underlying information model. Postmarketing Safety Study Tool lets the clinical researchers extract data from different EHR systems by designing data collection set schemas through common data elements. The tool interacts with a semantic metadata registry through IHE data element exchange profile. Postmarketing Safety Study Tool and its supporting components have been implemented and deployed on the central data warehouse of the Lombardy region, Italy, which contains anonymized records of about 16 million patients with over 10-year longitudinal data on average. Clinical researchers in Roche validate the tool with real life use cases. PMID:26543873

  20. Maltreatment and Disabilities: A Population-based Epidemiological Study.

    ERIC Educational Resources Information Center

    Sullivan, Patricia M.; Knutson, John F.

    2000-01-01

    This study reviewed merged records of children (N=40,211, 3,262 disabled) in Omaha, Nebraska, during 1994-95. An electronic merger of school records with child abuse, foster care, and police records was followed by a review of maltreatment incidents. Findings indicated a 9 percent prevalence rate of maltreatment for nondisabled children and a 31…

  1. An Inquiry into Expressive Writing: A Classroom-Based Study

    ERIC Educational Resources Information Center

    Bilton, Linda; Sivasubramaniam, Sivakumar

    2009-01-01

    This article makes a plea for using expressive writing in EFL/ESL writing courses. It examines the current unsatisfactory state of EFL/ESL writing and locates its causes in the pragmatic approach of textbook writers and practitioners. Next it reports a longitudinal case study of a university writing class at the upper-intermediate level of English…

  2. A Study of Multimedia Application-Based Vocabulary Acquisition

    ERIC Educational Resources Information Center

    Shao, Jing

    2012-01-01

    The development of computer-assisted language learning (CALL) has created the opportunity for exploring the effects of the multimedia application on foreign language vocabulary acquisition in recent years. This study provides an overview the computer-assisted language learning (CALL) and detailed a developing result of CALL--multimedia. With the…

  3. Web-Based Exchange of Views Enhances "Global Studies"

    ERIC Educational Resources Information Center

    Ahamer, Gilbert; Kumpfmuller, Karl A.; Hohenwarter, Michaela

    2011-01-01

    Purpose: The aim of this article is to present the development-oriented Master's curriculum "Global Studies" (GS) at the University of Graz, Austria, as an example of interdisciplinary academic training with the purpose of fostering inter-"cultural" understanding. It aims to show that scientific disciplines can be understood as "cultures of…

  4. Kibbutz Values in School-Based Curricula for Kibbutz Studies.

    ERIC Educational Resources Information Center

    Shoham, Edna

    1995-01-01

    Examines the question of how, and if, kibbutz social values are transmitted through kibbutz studies curricula. Determined that the accepted attitude of instructors (neutral and objective) was at odds with the inherent socialization of the kibbutz's mission. Includes a brief history of kibbutz development. (MJP)

  5. Computer-Based Concept Mapping: Active Studying for Active Learners.

    ERIC Educational Resources Information Center

    Anderson-Inman, Lynne; Zeitz, Leigh

    1993-01-01

    Describes the use of computer-generated concept maps using a new genre of graphics programs that allows students to create, alter and expand maps as they acquire more subject matter knowledge. Four examples of increasingly complex concept maps developed by a high school student studying cellular biology are discussed and illustrated. (Contains 19…

  6. A Study on Improving Information Processing Abilities Based on PBL

    ERIC Educational Resources Information Center

    Kim, Du Gyu; Lee, JaeMu

    2014-01-01

    This study examined an instruction method for the improvement of information processing abilities in elementary school students. Current elementary students are required to develop information processing abilities to create new knowledge for this digital age. There is, however, a shortage of instruction strategies for these information processing…

  7. Feasibility study of algae-based CO2 capture

    EPA Science Inventory

    Abstract: The biomass of microalgae contains approximately 50% carbon, which is commonly obtained from the atmosphere, but can also be taken from commercial sources that produce CO2, such as coal-fired power plants. A study of operational demonstration projects is being underta...

  8. Feasibility study of algae-based CO2 capture

    EPA Science Inventory

    The biomass of microalgae contains approximately 50% carbon, which is commonly obtained from the atmosphere, but can also be taken from commercial sources that produce CO2, such as coal-fired power plants. A study of operational demonstration projects is being undertaken to eval...

  9. Insect-Based Vision for Autonomous Vehicles: A Feasibility Study

    NASA Technical Reports Server (NTRS)

    Srinivasan, Mandyam V.

    1999-01-01

    The aims of the project were to use a high-speed digital video camera to pursue two questions: i) To explore the influence of temporal imaging constraints on the performance of vision systems for autonomous mobile robots; To study the fine structure of insect flight trajectories with in order to better understand the characteristics of flight control, orientation and navigation.

  10. Insect-Based Vision for Autonomous Vehicles: A Feasibility Study

    NASA Technical Reports Server (NTRS)

    Srinivasan, Mandyam V.

    1999-01-01

    The aims of the project were to use a high-speed digital video camera to pursue two questions: (1) To explore the influence of temporal imaging constraints on the performance of vision systems for autonomous mobile robots; (2) To study the fine structure of insect flight trajectories in order to better understand the characteristics of flight control, orientation and navigation.

  11. A Study of Computer-Based Instruction in Nursing Education.

    ERIC Educational Resources Information Center

    Conklin, D. N.

    1983-01-01

    Describes a comparative study of instruction in surgical nursing, which investigates the impact of computer-assisted instruction (CAI) on learning and student attitudes. Flowcharts of the computer-management program and CAI modules are included. Significant improvement was shown by the group using CAI. (EAO)

  12. Hypothyroidism and Lipid Levels in a Community Based Study (TTS)

    PubMed Central

    Alamdari, Shahram; Amouzegar, Atieh; Tohidi, Maryam; Gharibzadeh, Safoora; Kheirkhah, Pouyan; Kheirkhah, Parnian; Azizi, Fereidoun

    2015-01-01

    Background: Thyroid hormones play an important role in lipid metabolism. Overt hypothyroidism is known to be associated with increased lipid profiles, but the effect of subclinical hypothyroidism (SCH) on lipid profile remains controversial. Objectives: The aim of this study was to assess the association between thyroid disorders and serum lipid levels. Materials and Methods: The present study was conducted within the framework of Tehran lipid and glucose study (TLGS). Serum concentrations of TSH and FT4, cholesterol, triglycerides and HDL-C were measured in 5786 randomly selected subjects. Serum LDL was calculated according to the Friedwald formula. Results: The study assessed 5154 subjects including 42.5% males and 57.5% females, with a mean age of 39.71 ± 14.2 years (ranged 20 - 90 years). Serum cholesterol was significantly higher in overt hypothyroidism in comparison to subclinical hypothyroidism (P = 0.003). Serum cholesterol, HDL –C, LDL-C and TG did not differ between subclinical hypothyroid and control groups. Among euthyroid men, serum FT4 levels were inversely correlated with serum cholesterol and TG. In euthyroid women, serum FT4 levels were correlated positively with serum HDL-C and negatively correlated with TG and TG/HDL-C ratio and TSH levels were associated negatively with, HDL-C. Conclusions: No differences existed in lipid profiles between subclinical hypothyroidism and euthyroid subjects. There are correlations between serum FT4 and TSH and lipid profiles. PMID:27335579

  13. Laser-ARPES studies of BSCCO-BASED cuprate superconductors

    NASA Astrophysics Data System (ADS)

    Douglas, J. F.; Koralek, J. D.; Sun, Z.; Plumb, N. C.; Wang, Q.; Reber, T. J.; Griffith, J. D.; Aiura, Y.; Oka, K.; Eisaki, H.; Dessau, D. S.; Devereaux, T. P.; Johnson, S. S.

    2007-03-01

    Utilizing 6 eV and 7 eV laser light, we have performed high-resolution ANGLE RESOLVED PHOTOEMISSION studies of the BSCCO family of superconductors. This higher resolution, in both energy and momentum, has allowed the observation of interesting new doping- and temperature-dependent features in the nodal and near nodal dispersions in these materials.

  14. Characterizing Adolescent Prescription Misusers: A Population-Based Study

    ERIC Educational Resources Information Center

    Schepis, Ty S.; Krishnan-Sarin, Suchitra

    2008-01-01

    A study was conducted to investigate the risk factors associated with the abuse of opiods, stimulants, tranquilizers and other sedatives among adolescents aged between 12 to 17 years and the presence of one more symptoms of a substance use disorder from prescription misuse. Results indicated that poor academic performance; enjoyment of…

  15. Cryptosporidiosis in Indonesia: a hospital-based study and a community-based survey.

    PubMed

    Katsumata, T; Hosea, D; Wasito, E B; Kohno, S; Hara, K; Soeparto, P; Ranuh, I G

    1998-10-01

    Hospital-based and community-based studies were conducted to understand the prevalence and mode of transmission of Cryptosporidium parvum infection in Surabaya, Indonesia. In both studies people with and without diarrhea were examined for oocysts. A community-based survey included questionnaires to a community and stool examination of cats. Questionnaires covered demographic information, health status, and hygienic indicators. In the hospital, C. parvum oocysts were found in 26 (2.8%) of 917 patients with diarrhea and 15 (1.4%) of 1,043 control patients. The most susceptible age was less than two years old. The prevalence was higher during the rainy season. A community-based study again showed that C. parvum oocysts were frequently detected in diarrhea samples (8.2%), exclusively during rainy season. Thirteen (2.4%) of 532 cats passed C. parvum oocysts. A multiple logistic regression model indicated that contact with cats, rain, flood, and crowded living conditions are significant risk factors for Cryptosporidium infection. PMID:9790442

  16. A Thematic Review of Studies into the Effectiveness of Context-Based Chemistry Curricula

    ERIC Educational Resources Information Center

    Ultay, Neslihan; Calik, Muammer

    2012-01-01

    Context-based chemistry education aims at making connections between real life and the scientific content of chemistry courses. The purpose of this study was to evaluate context-based chemistry studies. In looking for the context-based chemistry studies, the authors entered the keywords "context-based", "contextual learning" and "chemistry…

  17. An instrument for the assessment of diarrhoeal severity based on a longitudinal community-based study

    PubMed Central

    Lee, Gwenyth; Peñataro Yori, Pablo; Paredes Olortegui, Maribel; Caulfield, Laura E; Sack, David A; Fischer-Walker, Christa; Black, Robert E; Kosek, Margaret

    2014-01-01

    Objective Diarrhoea is a significant contributer to morbidity and is among the leading causes of death of children living in poverty. As such, the incidence, duration and severity of diarrhoeal episodes in the household are often key variables of interest in a variety of community-based studies. However, there currently exists no means of defining diarrhoeal severity that are (A) specifically designed and adapted for community-based studies, (B) associated with poorer child outcomes and (C) agreed on by the majority of researchers. Clinical severity scores do exist and are used in healthcare settings, but these tend to focus on relatively moderate-to-severe dehydrating and dysenteric disease, require trained observation of the child and, given the variability of access and utilisation of healthcare, fail to sufficiently describe the spectrum of disease in the community setting. Design Longitudinal cohort study. Setting Santa Clara de Nanay, a rural community in the Northern Peruvian Amazon. Participants 442 infants and children 0–72 months of age. Main outcome measures Change in weight over 1-month intervals and change in length/height over 9-month intervals. Results Diarrhoeal episodes with symptoms of fever, anorexia, vomiting, greater number of liquid stools per day and greater number of total stools per day were associated with poorer weight gain compared with episodes without these symptoms. An instrument to measure the severity was constructed based on the duration of these symptoms over the course of a diarrhoeal episode. Conclusions In order to address limitations of existing diarrhoeal severity scores in the context of community-based studies, we propose an instrument comprised of diarrhoea-associated symptoms easily measured by community health workers and based on the association of these symptoms with poorer child growth. This instrument can be used to test the impact of interventions on the burden of diarrhoeal disease. PMID:24907244

  18. Studying Light in the Fifth Grade: A Case Study of Text-Based Science Teaching. Research Series No. 129.

    ERIC Educational Resources Information Center

    Slinger, Lucille A.; And Others

    This study documents text-based science instruction as it actually occurred in the classroom of a fifth-grade teacher teaching the unit on light found in "Exploring Science" by M.K. Blecha, P.C. Gega, and M. Green (1979, Laidlaw Brothers). The study, focusing on the nature of and reasons for the teacher's successes and failures, examined the…

  19. Lunar base surface mission operations. Lunar Base Systems Study (LBSS) task 4.1

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The purpose was to perform an analysis of the surface operations associated with a human-tended lunar base. Specifically, the study defined surface elements and developed mission manifests for a selected base scenario, determined the nature of surface operations associated with this scenario, generated a preliminary crew extravehicular and intravehicular activity (EVA/IVA) time resource schedule for conducting the missions, and proposed concepts for utilizing remotely operated equipment to perform repetitious or hazardous surface tasks. The operations analysis was performed on a 6 year period of human-tended lunar base operation prior to permanent occupancy. The baseline scenario was derived from a modified version of the civil needs database (CNDB) scenario. This scenario emphasizes achievement of a limited set of science and exploration objectives while emplacing the minimum habitability elements required for a permanent base.

  20. Dilatometer study of rapidly solidified aluminium-silicon based alloys

    NASA Astrophysics Data System (ADS)

    Varga, B.; Fazakas, E.; Hargitai, H.; Varga, L. K.

    2009-01-01

    Aluminum-Silicon alloys are sought in a large number of automotive and aerospace applications due to their low coefficient of thermal expansion and high wear resistance. The present study focused on structural transformations as a function of the temperature of rapidly solidified hypereutectic Al100-xSix (x = 12, 22 and 40) alloys. Different structures out of equilibrium have been obtained after casting in sand, graphite and copper moulds and by melt spinning. The retained Si content in supersaturated alpha Al and the precipitation of Si is discussed in the light of the dilatometer studies [1, 2, 3] complemented by metallographic microscopy, XRD and DSC [4] measurements. A Kissinger analysis was used to determine the activation energy for the precipitation of supersaturated Si content.

  1. FEASIBILITY STUDY II OF A MUON BASED NEUTRINO SOURCE.

    SciTech Connect

    GALLARDO,J.C.; OZAKI,S.; PALMER,R.B.; ZISMAN,M.

    2001-06-30

    The concept of using a muon storage ring to provide a well characterized beam of muon and electron neutrinos (a Neutrino Factory) has been under study for a number of years now at various laboratories throughout the world. The physics program of a Neutrino Factoryis focused on the relatively unexplored neutrino sector. In conjunction with a detector located a suitable distance from the neutrino source, the facility would make valuable contributions to the study of neutrino masses and lepton mixing. A Neutrino Factory is expected to improve the measurement accuracy of sin{sup 2}(2{theta}{sub 23}) and {Delta}m{sup 2}{sub 32} and provide measurements of sin{sup 2}(2{theta}{sub 13}) and the sign of {Delta}m{sup 2}{sub 32}. It may also be able to measure CP violation in the lepton sector.

  2. A computerized data base system for medical diagnostic studies (Diastu).

    PubMed

    Rosen, I I; Hall, T C; Mettler, F; Wicks, J; Kelsey, C A; Gustafson, D E

    1980-12-01

    A computerized database system (DIASTU) has been developed for the storage and selective retrieval of the results of medical diagnostic studies. The system is being used to analyze the disease process and the efficacy and yield of selected diagnostic studies. The system runs on a DEC PDP-11/60 computer. It consists of three FORTRAN IV programs linked to a general-purpose assembly language database handler. One program, DSENT, interactively modifies the information in the database. The second, DSLIST, prints all or portions of the database. The third program, DSTAT, interactively assembles the parameters for selective searches of the database and executes them. A query language is used that allows the use of time and size specifications and Boolean operators in nested loops. PMID:7249603

  3. Pharmacokinetic study of medicinal polymers: models based on dextrans

    SciTech Connect

    Kulakov, V.N.; Pimenova, G.N.; Matveev, V.A.; Sedov, V.V.; Vasil'ev, A.E.

    1986-09-01

    The authors study the pharmacokinetics of dextrans with various molecular masses modified by fluorescein isothiocyanate (FITC) using a radioisotope method. The radionuclide /sup 125/I was selectively bound to a FITC residue attached to the polysaccharide by electrochemical iodination under potentiostatic conditions. In the experiments, dextrans modified by FITC were labeled with /sup 125/I (DF-/sup 125/I) by electrochemical iodination. The separation of DF-/sup 125/I and FITC from ionic forms of the radionuclide not bound to the polymer was carried out. The properties of the samples obtained are presented. The radioactivity accumulated in the rate organs and urine studied are shown. The features of DF-/sup 125/I behavior in the blood and liver are examined.

  4. Evidenced-based review of clinical studies on endodontic diagnosis.

    PubMed

    2009-08-01

    The practice of endodontics requires excellence in diagnostic skills. The importance of this topic has been underscored by a recent 2008 AAE-sponsored symposium on endodontic diagnosis, which will be highlighted in a special issue of the Journal of Endodontics. In this minireview, we focus on recent clinical studies that emphasize different aspects related to the diagnosis of disorders of the pulp-dentin complex. PMID:19631854

  5. Study of solar cells based on upgraded metallurgical grade silicon

    NASA Astrophysics Data System (ADS)

    Schlosser, V.; Kuchar, F.; Seeger, K.

    A study is presented on the applicability of diffused solar cells when cast upgraded metallurgical grade silicon (UMG-Si) is used. Cells have been prepared from differently processed UMG-Si and for comparison from high purity FZ-Si. The material was characterized by the minority carrier diffusion length, which was obtained from spectral response measurements. A two-diode equivalent circuit model was used in order to evaluate pn-junction characteristics under illumination and in the dark.

  6. [Cataract: based on A-bomb survivor studies].

    PubMed

    Neriishi, Kazuo

    2012-03-01

    Until now, the radiation protection community had assumed that only high doses of 2 Gy or more cause cataracts. However, new data from the atomic-bomb (A-bomb) survivors suggest that the dose threshold for both minor opacities and vision limiting cataracts may be below 1 Gy. Other studies have shown similar results in recent years. In 2011, the International Commission on Radiological Protection (ICRP) revised their guidelines for permissible occupational and medical exposures to the eye. PMID:22514923

  7. Oviposition behaviour of Phlebotomus argentipes - A laboratory-based study

    PubMed Central

    Kumar, Vijay; Rama, Aarti; Kesari, Shreekant; Bhunia, Gouri Sankar; Dinesh, Diwakar Singh; Das, Pradeep

    2013-01-01

    The breeding habitat of sandflies is a little studied and poorly understood phenomenon. More importantly, oviposition behaviour is a largely neglected aspect of sandfly biology and this knowledge gap further undermines our understanding of the biology of sandflies. Pheromones released by the eggs play an important role in identifying good sites for oviposition by female insects. Several recent studies have examined the oviposition pheromone. The present study provides a preliminary report on the oviposition behaviour of Phlebotomus argentipes, the only vector of kala-azar (or visceral leishmaniasis) on the Indian sub-continent. Sandflies prefer to oviposit their eggs on surfaces that contain organic substances, especially substances with an odour of decaying animal products and the remains of conspecific eggs. The results presented here suggest that the odour released by the organic substances of old sandfly colony remains that contain dead flies, old unhatched eggs, larval food containing vertebrate faeces, frass and other organic matter serves as an attractant for the ovipositing females of P. argentipes and hence greatly increases the number of oviposited eggs compared to eggs deposited in controlled oviposition pots. This result will be helpful in maintaining an efficient colony of P. argentipes and may be a promising tool for monitoring and controlling the target insect as part of a synergistic approach. PMID:24141963

  8. Detection of electronically equivalent tautomers of adenine base: DFT study

    SciTech Connect

    Siddiqui, Shamoon Ahmad; Bouarissa, Nadir; Rasheed, Tabish; Al-Assiri, M.S.; Al-Hajry, A.

    2014-03-01

    Graphical abstract: - Highlights: • DFT calculations have been performed on adenine and its rare tautomer Cu{sup 2+} complexes. • Interaction of A-Cu{sup 2+} and rA-Cu{sup 2+} complexes with AlN modified fullerene (C{sub 60}) have been studied briefly. • It is found that AlN modified C{sub 60} could be used as a nanoscale sensor to detect these two A-Cu{sup 2+} and rA-Cu{sup 2+} complexes. - Abstract: In the present study, quantum chemical calculations were carried out to investigate the electronic structures and stabilities of adenine and its rare tautomer along with their Cu{sup 2+} complexes. Density Functional Theory (B3LYP method) was used in all calculations. The two Cu{sup 2+} complexes of adenine have almost similar energies and electronic structures; hence, their chemical differentiation is very difficult. For this purpose, interactions of these complexes with AlN modified fullerene (C{sub 60}) have been studied. Theoretical investigations reveal that AlN-doped C{sub 60} may serve as a potentially viable nanoscale sensor for detection of the two Cu{sup 2+} complexes of adenine.

  9. Electroresistance and field effect studies on manganite based heterostructure

    SciTech Connect

    Solanki, P. S.; Khachar, Uma; Vagadia, Megha; Ravalia, Ashish; Katba, Savan; Kuberkar, D. G.

    2015-04-14

    Electronic properties of manganites are significantly important for various spintronic applications such as microelectronics, magnetic data storage, communication technologies, and memory devices. Influence of applied electric field on the room temperature charge transport in ZnO/La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/SrNb{sub 0.002}Ti{sub 0.998}O{sub 3} (SNTO) heterostructure has been investigated using field effect studies. Large negative and positive electroresistance has been observed in heterostructure under various possible circuit geometries. Field effect studies have been carried out using three different circuit geometries, namely: (i) ZnO as a control electrode (E{sub LZ}), (ii) SNTO as a control electrode (E{sub LS}), and (iii) shorted ZnO and SNTO as control electrodes (E{sub LZS}). For this, channel electric field (E{sub CH}) dependent variation in channel resistance (R{sub C}) (of manganite channel) and I-V (across manganite channel) under various control fields (E{sub C}) have been studied. Variation in barrier height (Φ{sub B}) with control field (E{sub C}) for different geometries has been discussed.

  10. Drug-DNA Interaction Studies of Acridone-Based Derivatives.

    PubMed

    Thimmaiah, Kuntebomanahalli; Ugarkar, Apoorva G; Martis, Elvis F; Shaikh, Mushtaque S; Coutinho, Evans C; Yergeri, Mayur C

    2015-01-01

    N10-alkylated 2-bromoacridones are a novel series of potent antitumor compounds. DNA binding studies of these compounds were carried out using spectrophotometric titrations, Circular dichroism (CD) measurements using Calf Thymus DNA (CT DNA). The binding constants were identified at a range of K=0.3 to 3.9×10(5) M(-1) and the percentage of hypochromism from the spectral titrations at 28-54%. This study has identified a compound 9 with the good binding affinity of K=0.39768×10(5) M(-1) with CT DNA. Molecular dynamics (MD) simulations have investigated the changes in structural and dynamic features of native DNA on binding to the active compound 9. All the synthesized compounds have increased the uptake of Vinblastine in MDR KBChR-8-5 cells to an extent of 1.25- to1.9-fold than standard modulator Verapamil of similar concentration. These findings allowed us to draw preliminary conclusions about the structural features of 2-bromoacridones and further chemical enhancement will improve the binding affinity of the acridone derivatives to CT-DNA for better drug-DNA interaction. The molecular modeling studies have shown mechanism of action and the binding modes of the acridones to DNA. PMID:25874941