WorldWideScience

Sample records for experimental challenges varied

  1. Pollinator effectiveness varies with experimental shifts in flowering time.

    Science.gov (United States)

    Rafferty, Nicole E; Ives, Anthony R

    2012-04-01

    The earlier flowering times exhibited by many plant species are a conspicuous sign of climate change. Altered phenologies have caused concern that species could suffer population declines if they flower at times when effective pollinators are unavailable. For two perennial wildflowers, Tradescantia ohiensis and Asclepias incarnata, we used an experimental approach to explore how changing phenology affects the taxonomic composition of the pollinator assemblage and the effectiveness of individual pollinator taxa. After finding in the previous year that fruit set varied with flowering time, we manipulated flowering onset in greenhouses, placed plants in the field over the span of five weeks, and measured pollinator effectiveness as the number of seeds produced after a single visit to a flower. The average effectiveness of pollinators and the expected rates of pollination success were lower for plants of both species flowering earlier than for plants flowering at historical times, suggesting there could be reproductive costs to earlier flowering. Whereas for A. incarnata, differences in average seed set among weeks were due primarily to changes in the composition of the pollinator assemblage, the differences for T. ohiensis were driven by the combined effects of compositional changes and increases over time in the effectiveness of some pollinator taxa. Both species face the possibility of temporal mismatch between the availability of the most effective pollinators and the onset of flowering, and changes in the effectiveness of individual pollinator taxa through time may add an unexpected element to the reproductive consequences of such mismatches.

  2. Mate preference of female blue tits varies with experimental photoperiod.

    Directory of Open Access Journals (Sweden)

    Laura B Reparaz

    Full Text Available Organisms use environmental cues to time their life-cycles and among these cues, photoperiod is the main trigger of reproductive behaviours such as territory defence or song activity. Whether photoperiod is also important for another behaviour closely associated with reproduction, mate choice, is unknown. In many bird species, mate choice occurs at two different times during the annual cycle that strongly differ in daylength: in late winter when photoperiod is short and social mates are chosen, and again around egg-laying when photoperiod is longer and extra-pair mates are chosen. This duality makes the role that photoperiod plays on mate choice behaviours intriguing. We investigated the effect of photoperiod on mate choice using three experimental photoperiodic treatments (9 L:15 D, 14 L:10 D, 18 L:6 D, using blue tits (Cyanistes caeruleus as a biological model. We show that female choice was stronger under long photoperiods. In addition, female blue tits spent significantly more time near males with long tarsi and long wings. This latter preference was only expressed under long photoperiods, suggesting that some indices of male quality only become significant to females when they are strongly photostimulated, and therefore that females could select their social and extra-pair mates based on different phenotypic traits. These results shed light on the roles that photoperiod may play in stimulating pair-bonding and in refining female selectivity for male traits.

  3. Experimental Challenges to Stiffness as a Transport Paradigm

    Science.gov (United States)

    Luce, T. C.

    2017-10-01

    Transport in plasmas is treated experimentally as a relationship between gradients and fluxes in analogy to the random-walk problem. Gyrokinetic models often predict strong increases in local flux for small increases in local gradient when above a threshold, holding all other parameters fixed. This has been named `stiffness'. The radial scalelength is then expected to vary little with source strength as a result of high stiffness. To probe the role of ExB shearing on stiffness in the DIII-D tokamak, two neutral beam injection power scans in H-mode plasmas were specially crafted-one with constant, low torque and one with increasing torque. The ion heat, electron heat, and ion toroidal momentum transport do not show expected signatures of stiffness, while the ion particle transport does. The ion heat transport shows the clearest discrepancy; the normalized heat flux drops with increasing inverse ion temperature scalelength. ExB shearing affects the transport magnitude, but not the scalelength dependence. Linear gyrofluid (TGLF) and nonlinear gyrokinetic (GYRO) predictions show stiff ion heat transport around the experimental profiles. The ion temperature gradient required to match the ion heat flux with increasing auxiliary power is not correctly described by TGLF, even when parameters are varied within the experimental uncertainties. TGLF also underpredicts transport at smaller radii, but overpredicts transport at larger radii. Independent of the theory/experiment comparison, it is not clear that the theoretical definition of stiffness yields any prediction about parameter scans such as the power scans here, because the quantities that must be held fixed to quantify stiffness are varied. A survey of recent literature indicated that profile resilience is routinely attributed to stiffness, but simple model calculations show profile resilience does not imply stiffness. Taken together, these observations challenge the use of local stiffness as a paradigm for explaining

  4. Experimental study on the critical heat flux in a varying acceleration field, (1)

    International Nuclear Information System (INIS)

    Kusunoki, Tsuyoshi; Yokomura, Takeyoshi; Otsuji, Tomoo; Ikawa, Masahiro; Kurosawa, Akira.

    1988-12-01

    It is very important for the thermohydraulic design and for the safety assesement of marine reactors, to understand the effect of varying acceleration induced by ship motion on critical heart flux. The purpose of this joint study is to examine quantitatively the influence of varying acceleration on the behavior of bubbles. In the experiment, FREON-113 was used as working fluid. This report describes some experimental results; measurements of void fraction and bubble velocity near the heat transfer surface, measurement of bubble size under stationary acceleration field and observation of bubble behavior under varying acceleration field. (author)

  5. Superheavy Elements Challenge Experimental and Theoretical Chemistry

    CERN Document Server

    Zvára, I

    2003-01-01

    When reflecting on the story of superheavy elements, the an experimenter, acknowledges the role, which the predictions of nuclear and chemical theories have played in ongoing studies. Today, the problems of major interest for experimental chemistry are the studies of elements 112 and 114 including their chemical identification. Advanced quantum chemistry calculations of atoms and molecules would be of much help. First experiments with element 112 evidence that the metal is much more volatile and inert than mercury.

  6. Positive and negative variations in capacitive images for given defects under varying experimental conditions

    Science.gov (United States)

    Li, Chen; Yin, Xiaokang; Li, Zhen; Li, Wei; Chen, Guoming

    2018-04-01

    Capacitive imaging (CI) technique is a novel electromagnetic NDE technique. The Quasi-static electromagnetic field from the carefully designed electrode pair will vary when the electrical properties of the sample change, leading to the possibility of imaging. It is observed that for a given specimen, the targeted features appear as different variations in capacitive images under different experimental conditions. In some cases, even opposite variations occur, which brings confusion to indication interpretation. It is thus thought interesting to embark on investigations into the cause and effects of the negative variation phenomenon. In this work, the positive and negative variations were first explained from the measurement sensitivity distribution perspective. This was then followed by a detailed analysis using finite element models in COMSOL. A parametric experimental study on a glass fiber composite plate with artificial defects was then carried out to investigate how the experimental conditions affect the variation.

  7. Some current experimental challenges in elementary particle physics

    Energy Technology Data Exchange (ETDEWEB)

    Cline, D.B. (California Univ., Los Angeles (USA). Dept. of Physics)

    1990-06-01

    We describe three experimental challenges for experimental elementary particle physics: (1) the ongoing search for flavor changing weak neutral currents, including future prospect for a anti BB factory, (2) the status of the tests of the standard model in the W, Z and t quark sectors and (3) some current search for physics beyond the standard model, to include the possibility of searching for CPT violation using a {Phi} factory. (orig.).

  8. Challenges in modelling spatiotemporally varying phytoplankton blooms in the Northwestern Arabian Sea and Gulf of Oman

    Science.gov (United States)

    Sedigh Marvasti, S.; Gnanadesikan, A.; Bidokhti, A. A.; Dunne, J. P.; Ghader, S.

    2015-07-01

    We examine interannual variability of phytoplankton blooms in northwestern Arabian Sea and Gulf of Oman. Satellite data (SeaWIFS ocean color) shows two climatological blooms in this region, a wintertime bloom peaking in February and a summertime bloom peaking in September. A pronounced anti-correlation between the AVISO sea surface height anomaly (SSHA) and chlorophyll is found during the wintertime bloom. On a regional scale, interannual variability of the wintertime bloom is thus dominated by cyclonic eddies which vary in location from one year to another. These results were compared against the outputs from three different 3-D Earth System models. We show that two coarse (1°) models with the relatively complex biogeochemistry (TOPAZ) capture the annual cycle but neither eddies nor the interannual variability. An eddy-resolving model (GFDL CM2.6) with a simpler biogeochemistry (miniBLING) displays larger interannual variability, but overestimates the wintertime bloom and captures eddy-bloom coupling in the south but not in the north. The southern part of the domain is a region with a much sharper thermocline and nutricline relatively close to the surface, in which eddies modulate diffusive nutrient supply to the surface (a mechanism not previously emphasized in the literature). We suggest that for the model to simulate the observed wintertime blooms within cyclones, it will be necessary to represent this relatively unusual nutrient structure as well as the cyclonic eddies. This is a challenge in the Northern Arabian Sea as it requires capturing the details of the outflow from the Persian Gulf.

  9. Challenges in modeling spatiotemporally varying phytoplankton blooms in the Northwestern Arabian Sea and Gulf of Oman

    Science.gov (United States)

    Sedigh Marvasti, S.; Gnanadesikan, A.; Bidokhti, A. A.; Dunne, J. P.; Ghader, S.

    2016-02-01

    Recent years have shown an increase in harmful algal blooms in the Northwest Arabian Sea and Gulf of Oman, raising the question of whether climate change will accelerate this trend. This has led us to examine whether the Earth System Models used to simulate phytoplankton productivity accurately capture bloom dynamics in this region - both in terms of the annual cycle and interannual variability. Satellite data (SeaWIFS ocean color) show two climatological blooms in this region, a wintertime bloom peaking in February and a summertime bloom peaking in September. On a regional scale, interannual variability of the wintertime bloom is dominated by cyclonic eddies which vary in location from one year to another. Two coarse (1°) models with the relatively complex biogeochemistry (TOPAZ) capture the annual cycle but neither eddies nor the interannual variability. An eddy-resolving model (GFDL CM2.6) with a simpler biogeochemistry (miniBLING) displays larger interannual variability, but overestimates the wintertime bloom and captures eddy-bloom coupling in the south but not in the north. The models fail to capture both the magnitude of the wintertime bloom and its modulation by eddies in part because of their failure to capture the observed sharp thermocline and/or nutricline in this region. When CM2.6 is able to capture such features in the Southern part of the basin, eddies modulate diffusive nutrient supply to the surface (a mechanism not previously emphasized in the literature). For the model to simulate the observed wintertime blooms within cyclones, it will be necessary to represent this relatively unusual nutrient structure as well as the cyclonic eddies. This is a challenge in the Northern Arabian Sea as it requires capturing the details of the outflow from the Persian Gulf - something that is poorly done in global models.

  10. Pollinator-mediated interactions in experimental arrays vary with neighbor identity.

    Science.gov (United States)

    Ha, Melissa K; Ivey, Christopher T

    2017-02-01

    Local ecological conditions influence the impact of species interactions on evolution and community structure. We investigated whether pollinator-mediated interactions between coflowering plants vary with plant density, coflowering neighbor identity, and flowering season. We conducted a field experiment in which flowering time and floral neighborhood were manipulated in a factorial design. Early- and late-flowering Clarkia unguiculata plants were placed into arrays with C. biloba neighbors, noncongeneric neighbors, additional conspecific plants, or no additional plants as a density control. We compared whole-plant pollen limitation of seed set, pollinator behavior, and pollen deposition among treatments. Interactions mediated by shared pollinators depended on the identity of the neighbor and possibly changed through time, although flowering-season comparisons were compromised by low early-season plant survival. Interactions with conspecific neighbors were likely competitive late in the season. Interactions with C. biloba appeared to involve facilitation or neutral interactions. Interactions with noncongeners were more consistently competitive. The community composition of pollinators varied among treatment combinations. Pollinator-mediated interactions involved competition and likely facilitation, depending on coflowering neighbor. Experimental manipulation helped to reveal context-dependent variation in indirect biotic interactions. © 2017 Botanical Society of America.

  11. Physics potential and experimental challenges of the LHC luminosity upgrade

    CERN Document Server

    Gianotti, F.; Virdee, T.; Abdullin, S.; Azuelos, G.; Ball, A.; Barberis, D.; Belyaev, A.; Bloch, P.; Bosman, M.; Casagrande, L.; Cavalli, D.; Chumney, Pamela R.K.; Cittolin, S.; Dasu, S.; De Roeck, A.; Ellis, N.; Farthouat, P.; Fournier, D.; Hansen, J.B.; Hinchliffe, I.; Hohlfeld, M.; Huhtinen, M.; Jakobs, K.; Joram, C.; Mazzucato, F.; Mikenberg, G.; Miagkov, A.; Moretti, M.; Moretti, S.; Niinikoski, T.; Nikitenko, A.; Nisati, A.; Paige, F.; Palestini, S.; Papadopoulos, C.G.; Piccinini, F.; Pittau, R.; Polesello, G.; Richter-Was, E.; Sharp, P.; Slabospitsky, S.R.; Smith, W.H.; Stapnes, S.; Tonelli, G.; Tsesmelis, E.; Usubov, Z.; Vacavant, L.; van der Bij, J.; Watson, A.; Wielers, M.

    2005-01-01

    We discuss the physics potential and the experimental challenges of an upgraded LHC running at an instantaneous luminosity of 10**35 cm-2s-1. The detector R&D needed to operate ATLAS and CMS in a very high radiation environment and the expected detector performance are discussed. A few examples of the increased physics potential are given, ranging from precise measurements within the Standard Model (in particular in the Higgs sector) to the discovery reach for several New Physics processes

  12. Experimental evidence for amplitude death induced by a time-varying interaction

    Energy Technology Data Exchange (ETDEWEB)

    Suresh, K. [Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India); Shrimali, M.D. [Department of Physics, Central University of Rajasthan, NH-8, Bandar Sindri, Ajmer 305 801 (India); Prasad, Awadhesh [Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India); Thamilmaran, K., E-mail: maran.cnld@gmail.com [Centre for Nonlinear Dynamics, School of Physics, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu (India)

    2014-08-01

    In this paper, we study the time-varying interaction in coupled oscillatory systems. For this purpose, we have designed a novel time-varying resistive network using an analog switch and inverter circuits. We have applied this time-varying resistive network to mutually coupled identical Chua's oscillators. When the resistances are varied in time, we find that amplitude death arises in coupled identical oscillators. This has been observed numerically as well as verified through hardware experiments. - Highlights: • We have implemented the time-varying interaction in coupled oscillatory systems. • We have designed a novel time-varying resistive network using an analog switch and inverter circuits. • When the resistances are varied in time, we find that amplitude death arises in coupled identical oscillators.

  13. Host transcriptional responses following ex vivo re-challenge with Mycobacterium tuberculosis vary with disease status.

    Directory of Open Access Journals (Sweden)

    Elaine A Yu

    Full Text Available The identification of immune correlates that are predictive of disease outcome for tuberculosis remains an ongoing challenge. To address this issue, we evaluated gene expression profiles from peripheral blood mononuclear cells following ex vivo challenge with Mycobacterium tuberculosis, among participants with active TB disease (ATBD, n = 10, latent TB infection (LTBI, n = 10, and previous active TB disease (after successful treatment; PTBD, n = 10, relative to controls (n = 10. Differential gene expression profiles were assessed by suppression-subtractive hybridization, dot blot, real-time polymerase chain reaction, and the comparative cycle threshold methods. Comparing ATBD to control samples, greater fold-increases of gene expression were observed for a number of chemotactic factors (CXCL1, CXCL3, IL8, MCP1, MIP1α. ATBD was also associated with higher IL1B gene expression, relative to controls. Among LTBI samples, gene expression of several chemotactic factors (CXCL2, CXCL3, IL8 was similarly elevated, compared to individuals with PTBD. Our results demonstrated that samples from participants with ATBD and LTBI have distinct gene expression profiles in response to ex vivo M. tuberculosis infection. These findings indicate the value in further characterizing the peripheral responses to M. tuberculosis challenge as a route to defining immune correlates of disease status or outcome.

  14. Host transcriptional responses following ex vivo re-challenge with Mycobacterium tuberculosis vary with disease status.

    Science.gov (United States)

    Yu, Elaine A; John, Serene H; Tablante, Elizabeth C; King, Christine A; Kenneth, John; Russell, David G; Mehta, Saurabh

    2017-01-01

    The identification of immune correlates that are predictive of disease outcome for tuberculosis remains an ongoing challenge. To address this issue, we evaluated gene expression profiles from peripheral blood mononuclear cells following ex vivo challenge with Mycobacterium tuberculosis, among participants with active TB disease (ATBD, n = 10), latent TB infection (LTBI, n = 10), and previous active TB disease (after successful treatment; PTBD, n = 10), relative to controls (n = 10). Differential gene expression profiles were assessed by suppression-subtractive hybridization, dot blot, real-time polymerase chain reaction, and the comparative cycle threshold methods. Comparing ATBD to control samples, greater fold-increases of gene expression were observed for a number of chemotactic factors (CXCL1, CXCL3, IL8, MCP1, MIP1α). ATBD was also associated with higher IL1B gene expression, relative to controls. Among LTBI samples, gene expression of several chemotactic factors (CXCL2, CXCL3, IL8) was similarly elevated, compared to individuals with PTBD. Our results demonstrated that samples from participants with ATBD and LTBI have distinct gene expression profiles in response to ex vivo M. tuberculosis infection. These findings indicate the value in further characterizing the peripheral responses to M. tuberculosis challenge as a route to defining immune correlates of disease status or outcome.

  15. Responses to high-fat challenges varying in fat type in subjects with different metabolic risk phenotypes: a randomized trial.

    Directory of Open Access Journals (Sweden)

    Susan J van Dijk

    Full Text Available The ability of subjects to respond to nutritional challenges can reflect the flexibility of their biological system. Nutritional challenge tests could be used as an indicator of health status but more knowledge on metabolic and immune responses of different subjects to nutritional challenges is needed. The aim of this study was to compare the responses to high-fat challenges varying in fat type in subjects with different metabolic risk phenotypes.In a cross-over design 42 men (age 50-70 y consumed three high-fat shakes containing saturated fat (SFA, monounsaturated fat (MUFA or n-3 polyunsaturated (PUFA. Men were selected on BMI and health status (lean, obese or obese diabetic and phenotyped with MRI for adipose tissue distribution. Before and 2 and 4 h after shake consumption blood was drawn for measurement of expression of metabolic and inflammation-related genes in peripheral blood mononuclear cells (PBMCs, plasma triglycerides (TAG, glucose, insulin, cytokines and ex vivo PBMC immune response capacity. The MUFA and n-3 PUFA challenge, compared to the SFA challenge, induced higher changes in expression of inflammation genes MCP1 and IL1β in PBMCs. Obese and obese diabetic subjects had different PBMC gene expression and metabolic responses to high-fat challenges compared to lean subjects. The MUFA challenge induced the most pronounced TAG response, mainly in obese and obese diabetic subjects.The PBMC gene expression response and metabolic response to high-fat challenges were affected by fat type and metabolic risk phenotype. Based on our results we suggest using a MUFA challenge to reveal differences in response capacity of subjects.ClinicalTrials.gov NCT00977262.

  16. Physics potential and experimental challenges of the LHC luminosity upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Gianotti, F.; Ball, A.; Bloch, P.; Casagrande, L.; Cittolin, S.; Roeck, A. de; Ellis, N.; Farthouat, P.; Hansen, J.-B. [CERN, Experimental Physics Division, Geneva (Switzerland); Mangano, M.L. [CERN, Theoretical Physics Division, Geneva (Switzerland); Virdee, T. [CERN, Experimental Physics Division, Geneva (Switzerland); Imperial College, London (United Kingdom); Abdullin, S. [University of Maryland (United States); Azuelos, G. [University of Montreal, Group of Particle Physics, Montreal (Canada); Barberis, D. [Universita di Genova, Dipartimento di Fisica and INFN (Italy); Belyaev, A. [Florida State University, Tallahassee, FL (United States); Bosman, M. [IFAE, Barcelona (Spain); Cavalli, D. [INFN, Milano (Italy); Chumney, P.; Dasu, S. [Univ. of Wisconsin, Madison, WI (United States); Fournier, D. [LAL, Orsay (France); Hinchliffe, I.; Hohlfeld, M.; Huhtinen, M.; Jakobs, K.; Joram, C.; Mazzucato, F.; Mikenberg, G.; Miagkov, A.; Moretti, M.; Moretti, S.; Niinikoski, T.; Nikitenko, A.; Nisati, A.; Paige, F.; Palestini, S.; Papadopoulos, C.G.; Piccinini, F.; Pittau, R.; Polesello, G.; Richter-Was, E.; Sharp, P.; Slabospitsky, S.R.; Smith, W.H.; Stapnes, S.; Tonelli, G.; Tsesmelis, E.; Usubov, Z.; Vacavant, L.; Bij, J. van der; Watson, A.; Wielers, M.

    2004-02-01

    We discuss the physics potential and the experimental challenges of an upgraded LHC running at an instantaneous luminosity of 10{sup 35} cm{sup -2}s{sup -1}. The detector R and D needed to operate ATLAS and CMS in a very high radiation environment and the expected detector performance are discussed. A few examples of the increased physics potential are given, ranging from precise measurements within the Standard Model (in particular in the Higgs sector) to the discovery reach for several New Physics processes. (orig.)

  17. An in vitro experimental study of flow past aortic valve under varied pulsatile conditions

    Science.gov (United States)

    Zhang, Ruihang; Zhang, Yan

    2017-11-01

    Flow past aortic valve represents a complex fluid-structure interaction phenomenon that involves pulsatile, vortical, and turbulent conditions. The flow characteristics immediately downstream of the valve, such as the variation of pulsatile flow velocity, formation of vortices, distribution of shear stresses, are of particular interest to further elucidate the role of hemodynamics in various aortic diseases. However, the fluid dynamics of a realistic aortic valve is not fully understood. Particularly, it is unclear how the flow fields downstream of the aortic valve would change under varied pulsatile inlet boundary conditions. In this study, an in vitro experiment has been conducted to investigate the flow fields downstream of a silicone aortic valve model within a cardiovascular flow simulator. Phased-locked Particle Image Velocimetry measurements were performed to map the velocity fields and Reynolds normal and shear stresses at different phases in a cardiac cycle. Temporal variations of pressure across the valve model were measured using high frequency transducers. Results have been compared for different pulsatile inlet conditions, including varied frequencies (heart rates), magnitudes (stroke volumes), and cardiac contractile functions (shapes of waveforms).

  18. The performance of cleaner wrasse, Labroides dimidiatus, in a reversal learning task varies across experimental paradigms

    Directory of Open Access Journals (Sweden)

    Simon Gingins

    2018-05-01

    Full Text Available Testing performance in controlled laboratory experiments is a powerful tool for understanding the extent and evolution of cognitive abilities in non-human animals. However, cognitive testing is prone to a number of potential biases, which, if unnoticed or unaccounted for, may affect the conclusions drawn. We examined whether slight modifications to the experimental procedure and apparatus used in a spatial task and reversal learning task affected performance outcomes in the bluestreak cleaner wrasse, Labroides dimidiatus (hereafter “cleaners”. Using two-alternative forced-choice tests, fish had to learn to associate a food reward with a side (left or right in their holding aquarium. Individuals were tested in one of four experimental treatments that differed slightly in procedure and/or physical set-up. Cleaners from all four treatment groups were equally able to solve the initial spatial task. However, groups differed in their ability to solve the reversal learning task: no individuals solved the reversal task when tested in small tanks with a transparent partition separating the two options, whereas over 50% of individuals solved the task when performed in a larger tank, or with an opaque partition. These results clearly show that seemingly insignificant details to the experimental set-up matter when testing performance in a spatial task and might significantly influence the outcome of experiments. These results echo previous calls for researchers to exercise caution when designing methodologies for cognition tasks to avoid misinterpretations.

  19. The performance of cleaner wrasse, Labroides dimidiatus, in a reversal learning task varies across experimental paradigms.

    Science.gov (United States)

    Gingins, Simon; Marcadier, Fanny; Wismer, Sharon; Krattinger, Océane; Quattrini, Fausto; Bshary, Redouan; Binning, Sandra A

    2018-01-01

    Testing performance in controlled laboratory experiments is a powerful tool for understanding the extent and evolution of cognitive abilities in non-human animals. However, cognitive testing is prone to a number of potential biases, which, if unnoticed or unaccounted for, may affect the conclusions drawn. We examined whether slight modifications to the experimental procedure and apparatus used in a spatial task and reversal learning task affected performance outcomes in the bluestreak cleaner wrasse, Labroides dimidiatus (hereafter "cleaners"). Using two-alternative forced-choice tests, fish had to learn to associate a food reward with a side (left or right) in their holding aquarium. Individuals were tested in one of four experimental treatments that differed slightly in procedure and/or physical set-up. Cleaners from all four treatment groups were equally able to solve the initial spatial task. However, groups differed in their ability to solve the reversal learning task: no individuals solved the reversal task when tested in small tanks with a transparent partition separating the two options, whereas over 50% of individuals solved the task when performed in a larger tank, or with an opaque partition. These results clearly show that seemingly insignificant details to the experimental set-up matter when testing performance in a spatial task and might significantly influence the outcome of experiments. These results echo previous calls for researchers to exercise caution when designing methodologies for cognition tasks to avoid misinterpretations.

  20. Experimental study on Kd of 137Cs at varying suspended load conditions

    International Nuclear Information System (INIS)

    Jaison, T.J.; Jain, Abhishek; Patra, A.K.; Ravi, P.M.; Tripathi, R.M.

    2018-01-01

    137 Cs is one of the radionuclide likely to be released through liquid effluents from a nuclear facility. It is soluble in water, but its mobility in aquatic environments is highly retarded by its strong interaction with suspended sediment. The 137 Cs + sorption by suspended load, especially in the subtropics and tropics are not fully understood. Besides, according to IAEA document in emergency situation 137 Cs and 131 I being marker radionuclides, are easier to identify and representative of all the other radionuclides present. Hence a laboratory study is carried out on sorption of 137 Cs with varying silt load, using the upstream lake water and sediments to estimate site specific distribution coefficient (K d )

  1. Experimental characterization of a concentrating photovoltaic system varying the light concentration

    International Nuclear Information System (INIS)

    Renno, C.; Petito, F.; Landi, G.; Neitzert, H.C.

    2017-01-01

    Highlights: • Experimental characterization of a concentrating photovoltaic system. • Analysis of the point-focus concentrating system performances. • Photovoltaic system parameters as function of the concentration factor. - Abstract: The concentrating photovoltaic system represents one of the most promising solar technologies because it allows a more efficient energy conversion. When a CPV system is designed, the main parameter which has to be considered is the concentration factor that affects both the system energy performances and its configuration. An experimental characterization of a CPV system previously realized at the University of Salerno, is presented in this paper considering several aspects related to the optical configuration, the concentration factor and the solar cell used. In particular, the parameters of an Indium Gallium Phosphide/Gallium Arsenide/Germanium triple-junction solar cell are investigated as function of the concentration factor determined by means of an experimental procedure that uses different optical configurations. The maximum concentration factor reached by the CPV system is 310 suns. The cell parameters dependence on the concentration is reported together with an electroluminescence analysis of the Indium Gallium Phosphide/Gallium Arsenide/Germanium cell. A monitoring of the electrical power provided by the system during its working is also presented corresponding to different direct irradiance values. A mean power of 2.95 W with an average efficiency of 32.8% is obtained referring to a mean irradiance of 930 W/m"2; lower values are obtained when the irradiance is highly fluctuating. The concentrating photovoltaic system electric energy output is estimated considering different concentration levels; the maximal obtained value is 23.5 W h on a sunny day at 310×. Finally, the temperature of the triple-junction solar cell is evaluated for different months in order to evaluate the potential annual thermal energy production

  2. Experimental investigations on steel-concrete composite columns for varying parameters

    Science.gov (United States)

    Aparna, V.; Vivek, D.; Neelima, Kancharla; Karthikeyan, B.

    2017-07-01

    In this study, the experimental investigations on steel tubes filled with different types of concrete are presented. Steel tubes filled with fibre reinforced concrete using lathe waste and steel tube with concerned confined with steel mesh were investigated. The combinations were compared with steel tubes with conventional concrete. A total of 4 concrete filled steel tube (CFST) combinations were made with tubes of diameter 100 mm with wall thickness 1.6 mm and a height of 300 mm. Axial compression test to examine the resisting capacity of the columns and push-out test for noting the bond strength were performed. Coupon tests were also conducted to determine the mechanical properties of steel. The structural behaviour of the composite columns was evaluated from on the test results. It was observed that steel tube filled fibre reinforced possessed better bond strength and resistance to axial load.

  3. Nitric oxide levels in the aqueous humor vary in different ocular hypertension experimental models

    Directory of Open Access Journals (Sweden)

    Da-Wen Lu

    2014-12-01

    Full Text Available This study investigated the relationships among intraocular pressure (IOP, nitric oxide (NO levels, and aqueous flow rates in experimental ocular hypertension models. A total of 75 rabbits were used. One of four different materials [i.e., α-chymotrypsin, latex microspheres (Polybead, red blood cell ghosts, or sodium hyaluronate (Healon GV] was injected into the eyes of the 15 animals in each experimental group; the remaining 15 rabbits were reserved for a control group. The IOP changes in the five groups were recorded on postinduction Days 1–3, Day 7, Day 14, Day 30, Day 60, Day 90, and Day 120. On postinduction Day 7, the dynamics and NO levels in the aqueous humor were recorded. Significant IOP elevations were induced by α-chymotrypsin (p < 0.01 and Polybead (p < 0.01 on each postinduction day. In the red blood cell ghosts model, significant elevations (p < 0.01 were found on postinduction Days 1–3; Healon GV significantly elevated IOP (p < 0.01 on postinduction Day 1 and Day 2. On postinduction Day 7, the aqueous humor NO levels increased significantly in the models of α-chymotrypsin, Polybead, and red blood cell ghosts (all p < 0.01, while the aqueous flow rates were significantly reduced in the models of α-chymotrypsin and Polybead (p < 0.005. Persistent ocular hypertension models were induced with α-chymotrypsin and Polybead in the rabbits. The Polybead model exhibited the characteristic of an increased aqueous humor NO level, similar to human eyes with acute angle-closure glaucoma and neovascular glaucoma.

  4. Theoretical and experimental investigations of efficient light coupling with spatially varied all dielectric striped waveguides

    Science.gov (United States)

    Yilmaz, Y. A.; Tandogan, S. E.; Hayran, Z.; Giden, I. H.; Turduev, M.; Kurt, H.

    2017-07-01

    Integrated photonic systems require efficient, compact, and broadband solutions for strong light coupling into and out of optical waveguides. The present work investigates an efficient optical power transferring the problem between optical waveguides having different widths of in/out terminals. We propose a considerably practical and feasible concept to implement and design an optical coupler by introducing gradually index modulation to the coupler section. The index profile of the coupler section is modulated with a Gaussian function by the help of striped waveguides. The effective medium theory is used to replace the original spatially varying index profile with dielectric stripes of a finite length/width having a constant effective refractive index. 2D and 3D finite-difference time-domain analyzes are utilized to investigate the sampling effect of the designed optical coupler and to determine the parameters that play a crucial role in enhancing the optical power transfer performance. Comparing the coupling performance of conventional benchmark adiabatic and butt couplers with the designed striped waveguide coupler, the corresponding coupling efficiency increases from approximately 30% to 95% over a wide frequency interval. In addition, to realize the realistic optical coupler appropriate to integrated photonic applications, the proposed structure is numerically designed on a silicon-on-insulator wafer. The implemented SOI platform based optical coupler operates in the telecom wavelength regime (λ = 1.55 μm), and the dimensions of the striped coupler are kept as 9.77 μm (along the transverse to propagation direction) and 7.69 μm (along the propagation direction) where the unit distance is fixed to be 465 nm. Finally, to demonstrate the operating design principle, the microwave experiments are conducted and the spot size conversion ratio as high as 7.1:1 is measured, whereas a coupling efficiency over 60% in the frequency range of 5.0-16.0 GHz has been also

  5. Salinization triggers a trophic cascade in experimental freshwater communities with varying food-chain length.

    Science.gov (United States)

    Hintz, William D; Mattes, Brian M; Schuler, Matthew S; Jones, Devin K; Stoler, Aaron B; Lind, Lovisa; Relyea, Rick A

    2017-04-01

    The application of road deicing salts in northern regions worldwide is changing the chemical environment of freshwater ecosystems. Chloride levels in many lakes, streams, and wetlands exceed the chronic and acute thresholds established by the United States and Canada for the protection of freshwater biota. Few studies have identified the impacts of deicing salts in stream and wetland communities and none have examined impacts in lake communities. We tested how relevant concentrations of road salt (15, 100, 250, 500, and 1000 mg Cl - /L) interacted with experimental communities containing two or three trophic levels (i.e., no fish vs. predatory fish). We hypothesized that road salt and fish would have a negative synergistic effect on zooplankton, which would then induce a trophic cascade. We tested this hypothesis in outdoor mesocosms containing filamentous algae, periphyton, phytoplankton, zooplankton, several macroinvertebrate species, and fish. We found that the presence of fish and high salt had a negative synergistic effect on the zooplankton community, which in turn caused an increase in phytoplankton. Contributing to the magnitude of this trophic cascade was a direct positive effect of high salinity on phytoplankton abundance. Cascading effects were limited with respect to impacts on the benthic food web. Periphyton and snail grazers were unaffected by the salt-induced trophic cascade, but the biomass of filamentous algae decreased as a result of competition with phytoplankton for light or nutrients. We also found direct negative effects of high salinity on the biomass of filamentous algae and amphipods (Hyalella azteca) and the mortality of banded mystery snails (Viviparus georgianus) and fingernail clams (Sphaerium simile). Clam mortality was dependent on the presence of fish, suggesting a non-consumptive interactive effect with salt. Our results indicate that globally increasing concentrations of road salt can alter community structure via both direct

  6. Experimental Challenges in Studying Hydrogen Absorption in Ultrasmall Metal Nanoparticles

    International Nuclear Information System (INIS)

    Zlotea, Claudia; Oumellal, Yassine; Provost, Karine; Ghimbeu, Camelia Matei

    2016-01-01

    Recent advances on synthesis, characterization, and hydrogen absorption properties of ultrasmall metal nanoparticles (defined here as objects with average size ≤3 nm) are briefly reviewed in the first part of this work. The experimental challenges encountered in performing accurate measurements of hydrogen absorption in Mg- and noble metal-based ultrasmall nanoparticles are addressed. The second part of this work reports original results obtained for ultrasmall bulk-immiscible Pd–Rh nanoparticles. Carbon-supported Pd–Rh nanoalloys in the whole binary chemical composition range have been successfully prepared by liquid impregnation method followed by reduction at 300°C. EXAFS investigations suggested that the local structure of these nanoalloys is partially segregated into Rh-rich core and Pd-rich surface coexisting within the same nanoparticles. Downsizing to ultrasmall dimensions completely suppresses the hydride formation in Pd-rich nanoalloys at ambient conditions, contrary to bulk and larger nanosized (5–6 nm) counterparts. The ultrasmall Pd 90 Rh 10 nanoalloy can absorb hydrogen-forming solid solutions under these conditions, as suggested by in situ X-ray diffraction (XRD). Apart from this composition, common laboratory techniques, such as in situ XRD, DSC, and PCI, failed to clarify the hydrogen interaction mechanism: either adsorption on developed surfaces or both adsorption and absorption with formation of solid solutions. Concluding insights were brought by in situ EXAFS experiments at synchrotron: ultrasmall Pd 75 Rh 25 and Pd 50 Rh 50 nanoalloys absorb hydrogen-forming solid solutions at ambient conditions. Moreover, the hydrogen solubility in these solid solutions is higher with increasing Pd content, and this trend can be understood in terms of hydrogen preferential occupation in the Pd-rich regions, as suggested by in situ EXAFS. The Rh-rich nanoalloys (Pd 25 Rh 75 and Pd 10 Rh 90 ) only adsorb hydrogen on the developed surface of ultrasmall

  7. Successful experimental challenge of dogs with canine parvovirus-2.

    OpenAIRE

    Carman, S; Povey, C

    1982-01-01

    Withholding food from dogs for 24 hours prior to, and for 48 hours following oral challenge with a gut mucosal homogenate of canine parvovirus-2, was a successful means of reproducing gastroenteric signs of canine parvovirus-2 infection. Twenty-one of 24 dogs, which had previously received various vaccine preparations of mink enteritis virus or were unvaccinated, and which were starved at challenge, developed soft or liquid feces with large or without large clots of mucus. Altered feces were ...

  8. Snow Leopard cloud : A multi-national education training and experimentation cloud and its security challenges

    NARCIS (Netherlands)

    Cayirci, E.; Rong, C.; Huiskamp, W.; Verkoelen, C.A.A.

    2009-01-01

    Military/civilian education training and experimentation networks (ETEN) are an important application area for the cloud computing concept. However, major security challenges have to be overcome to realize an ETEN. These challenges can be categorized as security challenges typical to any cloud and

  9. Challenges to Software/Computing for Experimentation at the LHC

    Science.gov (United States)

    Banerjee, Sunanda

    The demands of future high energy physics experiments towards software and computing have led the experiments to plan the related activities as a full-fledged project and to investigate new methodologies and languages to meet the challenges. The paths taken by the four LHC experiments ALICE, ATLAS, CMS and LHCb are coherently put together in an LHC-wide framework based on Grid technology. The current status and understandings have been broadly outlined.

  10. STRONG LENS TIME DELAY CHALLENGE. I. EXPERIMENTAL DESIGN

    Energy Technology Data Exchange (ETDEWEB)

    Dobler, Gregory [Kavli Institute for Theoretical Physics, University of California Santa Barbara, Santa Barbara, CA 93106 (United States); Fassnacht, Christopher D.; Rumbaugh, Nicholas [Department of Physics, University of California, 1 Shields Avenue, Davis, CA 95616 (United States); Treu, Tommaso; Liao, Kai [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Marshall, Phil [Kavli Institute for Particle Astrophysics and Cosmology, P.O. Box 20450, MS29, Stanford, CA 94309 (United States); Hojjati, Alireza [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, B.C. V6T 1Z1 (Canada); Linder, Eric, E-mail: tt@astro.ucla.edu [Lawrence Berkeley National Laboratory and University of California, Berkeley, CA 94720 (United States)

    2015-02-01

    The time delays between point-like images in gravitational lens systems can be used to measure cosmological parameters. The number of lenses with measured time delays is growing rapidly; the upcoming Large Synoptic Survey Telescope (LSST) will monitor ∼10{sup 3} strongly lensed quasars. In an effort to assess the present capabilities of the community, to accurately measure the time delays, and to provide input to dedicated monitoring campaigns and future LSST cosmology feasibility studies, we have invited the community to take part in a ''Time Delay Challenge'' (TDC). The challenge is organized as a set of ''ladders'', each containing a group of simulated data sets to be analyzed blindly by participating teams. Each rung on a ladder consists of a set of realistic mock observed lensed quasar light curves, with the rungs' data sets increasing in complexity and realism. The initial challenge described here has two ladders, TDC0 and TDC1. TDC0 has a small number of data sets, and is designed to be used as a practice set by the participating teams. The (non-mandatory) deadline for completion of TDC0 was the TDC1 launch date, 2013 December 1. The TDC1 deadline was 2014 July 1. Here we give an overview of the challenge, we introduce a set of metrics that will be used to quantify the goodness of fit, efficiency, precision, and accuracy of the algorithms, and we present the results of TDC0. Thirteen teams participated in TDC0 using 47 different methods. Seven of those teams qualified for TDC1, which is described in the companion paper.

  11. Experimental nuclear physics research challenges at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, E.; Morales G, L. [UNAM, Instituto de Fisica, Circuito Exterior, Ciudad Universitaria, 04510 Mexico D. F. (Mexico); Murillo O, G. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)

    2010-02-15

    Experimental research with low energy beams of ions (a few MeV) in nuclear physics has gone through a phase transition along its evolution in fifty years because of the increasing complexity (and cost) of the equipment required to conduct meaningful investigations. Many of the small cyclotrons and Van de Graaff (single ended and tandem) accelerators have been used for the last three decades mostly in applications related to the characterization and modification of materials. Specific experimental investigations in nuclear physics with low energy accelerators are proposed in this work. Specifically we discuss the topic of nuclear radii measurements of radioactive species produced via (d,n) reactions. Some emphasis is given to the instrumentation required. (Author)

  12. Natural experimentation is a challenging method for identifying headache triggers.

    Science.gov (United States)

    Houle, Timothy T; Turner, Dana P

    2013-04-01

    In this study, we set out to determine whether individual headache sufferers can learn about the potency of their headache triggers (causes) using only natural experimentation. Headache patients naturally use the covariation of the presence-absence of triggers with headache attacks to assess the potency of triggers. The validity of this natural experimentation has never been investigated. A companion study has proposed 3 assumptions that are important for assigning causal status to triggers. This manuscript examines one of these assumptions, constancy in trigger presentation, using real-world conditions. The similarity of day-to-day weather conditions over 4 years, as well as the similarity of ovarian hormones and perceived stress over a median of 89 days in 9 regularly cycling headache sufferers, was examined using several available time series. An arbitrary threshold of 90% similarity using Gower's index identified similar days for comparison. The day-to-day variability in just these 3 headache triggers is substantial enough that finding 2 naturally similar days for which to contrast the effect of a fourth trigger (eg, drinking wine vs not drinking wine) will only infrequently occur. Fluctuations in weather patterns resulted in a median of 2.3 days each year that were similar (range 0-27.4). Considering fluctuations in stress patterns and ovarian hormones, only 1.5 days/month (95% confidence interval 1.2-2.9) and 2.0 days/month (95% confidence interval 1.9-2.2), respectively, met our threshold for similarity. Although assessing the personal causes of headache is an age-old endeavor, the great many candidate triggers exhibit variability that may prevent sound conclusions without assistance from formal experimentation or statistical balancing. © 2013 American Headache Society.

  13. Genetic Resistance to Scrapie Infection in Experimentally Challenged Goats

    Science.gov (United States)

    Lacroux, Caroline; Perrin-Chauvineau, Cécile; Corbière, Fabien; Aron, Naima; Aguilar-Calvo, Patricia; Torres, Juan Maria; Costes, Pierrette; Brémaud, Isabelle; Lugan, Séverine; Schelcher, François; Barillet, Francis

    2014-01-01

    In goats, several field studies have identified coding mutations of the gene encoding the prion protein (I/M142, N/D146, S/D146, R/Q211, and Q/K222) that are associated with a lower risk of developing classical scrapie. However, the data related to the levels of resistance to transmissible spongiform encephalopathies (TSEs) of these different PRNP gene mutations are still considered insufficient for developing large-scale genetic selection against scrapie in this species. In this study, we inoculated wild-type (WT) PRNP (I142R154R211Q222) goats and homozygous and/or heterozygous I/M142, R/H154, R/Q211, and Q/K222 goats with a goat natural scrapie isolate by either the oral or the intracerebral (i.c.) route. Our results indicate that the I/M142 PRNP polymorphism does not provide substantial resistance to scrapie infection following intracerebral or oral inoculation. They also demonstrate that H154, Q211, and K222 PRNP allele carriers are all resistant to scrapie infection following oral exposure. However, in comparison to WT animals, the H154 and Q211 allele carriers displayed only moderate increases in the incubation period following i.c. challenge. After i.c. challenge, heterozygous K222 and a small proportion of homozygous K222 goats also developed the disease, but with incubation periods that were 4 to 5 times longer than those in WT animals. These results support the contention that the K222 goat prion protein variant provides a strong but not absolutely protective effect against classical scrapie. PMID:24284317

  14. Spent Fuel Transportation Package Performance Study - Experimental Design Challenges

    International Nuclear Information System (INIS)

    Snyder, A. M.; Murphy, A. J.; Sprung, J. L.; Ammerman, D. J.; Lopez, C.

    2003-01-01

    Numerous studies of spent nuclear fuel transportation accident risks have been performed since the late seventies that considered shipping container design and performance. Based in part on these studies, NRC has concluded that the level of protection provided by spent nuclear fuel transportation package designs under accident conditions is adequate. [1] Furthermore, actual spent nuclear fuel transport experience showcase a safety record that is exceptional and unparalleled when compared to other hazardous materials transportation shipments. There has never been a known or suspected release of the radioactive contents from an NRC-certified spent nuclear fuel cask as a result of a transportation accident. In 1999 the United States Nuclear Regulatory Commission (NRC) initiated a study, the Package Performance Study, to demonstrate the performance of spent fuel and spent fuel packages during severe transportation accidents. NRC is not studying or testing its current regulations, a s the rigorous regulatory accident conditions specified in 10 CFR Part 71 are adequate to ensure safe packaging and use. As part of this study, NRC currently plans on using detailed modeling followed by experimental testing to increase public confidence in the safety of spent nuclear fuel shipments. One of the aspects of this confirmatory research study is the commitment to solicit and consider public comment during the scoping phase and experimental design planning phase of this research

  15. The ropes and challenge course: a quasi-experimental examination.

    Science.gov (United States)

    Meyer, B B

    2000-06-01

    In answering the call for empirical documentation of the effect of ropes and challenge course participation on the psychosocial function and sport performance of athletes and teams, exploratory studies have identified postcourse changes in group cohesion and approaches to sport competition. The purpose of the current study was to utilize a pretest-posttest comparison group design to expand knowledge in this area. 35 members of a girls' high school tennis team participated. The 16 individuals who participated in a preseason program and the 19 individuals who did not comprised the treatment and comparison groups, respectively. Team members completed the Group Environment Questionnaire and the Sport Orientation Questionnaire four days prior to and two days after the course experience. A series of 2 x 2 analyses of variance, (group x time) run on each of the scales, gave a significant group x time interaction on one social cohesion scale but none for scores on the Sport Orientation Questionnaire. The findings are discussed in relation to research and the implementation of these programs with athletes.

  16. Performance of cable-in-conduit conductors in ITER [International Thermonuclear Experimental Reactor] toroidal field coils with varying heat loads

    International Nuclear Information System (INIS)

    Kerns, J.A.; Wong, R.L.

    1989-01-01

    The toroidal field (TF) coils in the International Thermonuclear Experimental Reactor (ITER) will operate with varying heat loads generated by ac losses and nuclear heating. The total heat load is estimated to be 2 kW per TF coil under normal operation and can be higher for different operating scenarios. Ac losses are caused by ramping the poloidal field (PF) for plasma initiation, burn, and shutdown; nuclear heating results from neutrons that penetrate into the coil past the shield. Present methods to reduce or eliminate these losses lead to larger and more expensive machines, which are unacceptable with today's budget constraints. A suitable solution is to design superconductors that operate with high heat loads. The cable-in-conduit conductor (CICC) can operate with high heat loads. One CICC design is analyzed for its thermal performance using two computer codes developed at LLNL. One code calculates the steady state flow conditions along the flow path, while the other calculates the transient conditions in the flow. We have used these codes to analyze the superconductor performance during the burn phase of the ITER plasma. The results of these analyses give insight to the choice of flow rate on superconductor performance. 4 refs., 5 figs

  17. Varying the number of bidders in the first-price sealed-bid auction: experimental evidence for the one-shot game

    NARCIS (Netherlands)

    Füllbrunn, S.C.; Neugebauer, T.

    2013-01-01

    The paper reports experimental data on the behavior in the first-price sealed-bid auction for a varying number of bidders when values and bids are private information. This feedback-free design is proposed for the experimental test of the one-shot game situation. We consider both within-subjects and

  18. Exercise persistence in the face of varying exercise challenges: a test of self-efficacy theory in working mothers.

    Science.gov (United States)

    Jung, Mary E; Brawley, Lawrence R

    2011-07-01

    Self-regulatory efficacy (SRE) should influence persistence towards goals. Mothers attempting to exercise while managing work and young children (N = 49, M(age) = 35.69, M(children) = 1.88) were stratified into high or low concurrent SRE groups, then randomized to read a hypothetical scenario detailing numerous or minimal exercise barrier conditions. Consistent with self-efficacy theory, when exercise barriers were numerous, mothers with higher concurrent SRE demonstrated greater persistence towards exercise goals, and perceived concurrent management of exercise with their other valued goals as more positively challenging, than mothers with lower concurrent SRE.

  19. Development of Snake Fungal Disease after Experimental Challenge with Ophidiomyces ophiodiicola in Cottonmouths (Agkistrodon piscivorous.

    Directory of Open Access Journals (Sweden)

    Matthew C Allender

    Full Text Available Snake fungal disease (SFD is a clinical syndrome associated with dermatitis, myositis, osteomyelitis, and pneumonia in several species of free-ranging snakes in the US. The causative agent has been suggested as Ophidiomyces ophiodiicola, but other agents may contribute to the syndrome and the pathogenesis is not understood. To understand the role of O. ophiodiicola in SFD, a cottonmouth snake model of SFD was designed. Five cottonmouths (Agkistrodon piscivorous were experimentally challenged by nasolabial pit inoculation with a pure culture of O. ophiodiicola. Development of skin lesions or facial swelling at the site of inoculation was observed in all snakes. Twice weekly swabs of the inoculation site revealed variable presence of O. ophiodiicola DNA by qPCR in all five inoculated snakes for 3 to 58 days post-inoculation; nasolabial flushes were not a useful sampling method for detection. Inoculated snakes had a 40% mortality rate. All inoculated snakes had microscopic lesions unilaterally on the side of the swabbed nasolabial pit, including erosions to ulcerations and heterophilic dermatitis. All signs were consistent with SFD; however, the severity of lesions varied in individual snakes, and fungal hyphae were only observed in 3 of 5 inoculated snakes. These three snakes correlated with post-mortem tissue qPCR evidence of O. ophiodiicola. The findings of this study conclude that O. ophiodiicola inoculation in a cottonmouth snake model leads to disease similar to SFD, although lesion severity and the fungal load are quite variable within the model. Future studies may utilize this model to further understand the pathogenesis of this disease and develop management strategies that mitigate disease effects, but investigation of other models with less variability may be warranted.

  20. Experimentally challenged reactivity of the hypothalamic pituitary adrenal axis in patients with recently diagnosed rheumatoid arthritis

    NARCIS (Netherlands)

    Dekkers, J. C.; Geenen, R.; Godaert, G. L.; Glaudemans, K. A.; Lafeber, F. P.; van Doornen, L. J.; Bijlsma, J. W.

    2001-01-01

    There is evidence that the hypothalamic pituitary adrenal (HPA) axis is subresponsive in patients with rheumatoid arthritis (RA). We assessed HPA axis responses to experimental stressors mimicking daily life challenges in patients with RA to determine whether HPA axis activity is associated with Th1

  1. An experimental Toxoplasma gondii dose response challenge model to study therapeutic or vaccine efficacy in cats

    NARCIS (Netherlands)

    Cornelissen, J.B.W.J.; Giessen, van der J.W.B.; Takumi, K.; Teunis, P.F.M.; Wisselink, H.J.

    2014-01-01

    High numbers of Toxoplasma gondii oocysts in the environment are a risk factor to humans. The environmental contamination might be reduced by vaccinating the definitive host, cats. An experimental challenge model is necessary to quantitatively assess the efficacy of a vaccine or drug treatment.

  2. Early host response in the mammary gland after experimental Streptococcus uberis challenge in heifers

    NARCIS (Netherlands)

    Greeff, de A.; Zadoks, R.N.; Ruuls, L.; Toussaint, M.; Nguyen, T.K.; Downing, A.; Rebel, J.M.J.; Stockhofe-Zurwieden, N.; Smith, H.E.

    2013-01-01

    Streptococcus uberis is a highly prevalent causative agent of bovine mastitis, which leads to large economic losses in the dairy industry. The aim of this study was to examine the host response during acute inflammation after experimental challenge with capsulated Strep. uberis. Gene expression in

  3. 21 CFR 130.17 - Temporary permits for interstate shipment of experimental packs of food varying from the...

    Science.gov (United States)

    2010-04-01

    ... require tests in interstate markets of the advantages to and acceptance by consumers of experimental packs... Administration, or good cause shown by the applicant, may provide for a longer test market period. The Food and... determined. (c) Any person desiring a permit may file with the Team Leader, Conventional Foods Team, Division...

  4. Varying the number of bidders in the first-price sealed-bid auction: experimental evidence for the one-shot game

    OpenAIRE

    Tibor Neugebauer; Sascha F llbrunn

    2013-01-01

    The paper reports experimental data on the behavior in the first-price sealed-bid auction for a varying number of bidders when values and bids are private information. This feedback-free design is proposed for the experimental test of the one-shot game situation. We consider both within-subject and betweensubjects variations. In line with the qualitative risk neutral Nash equilibrium prediction, the data show that bids increase in the number of bidders. However, in auctions involving a small ...

  5. Gravitational Waves from Coalescing Binary Black Holes: Theoretical and Experimental Challenges

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    (LIGO/VIRGO/GEO/...) is currently taking data near its planned sensitivity. Coalescing black hole binaries are among the most promising, and most exciting, gravitational wave sources for these detectors. The talk will review the theoretical and experimental challenges that must be met in order to successfully detect gravitational waves from coalescing black hole binaries, and to be able to reliably measure the physical parameters of the source (masses, spins, ...).

  6. LHC experimental data from today's data challenges to the promise of tomorrow

    CERN Multimedia

    CERN. Geneva; Panzer-Steindel, Bernd; Rademakers, Fons

    2003-01-01

    The LHC experiments constitute a challenge in several discipline in both High Energy Physics and Information Technologies. This is definitely the case for data acquisition, processing and analysis. This challenge has been addressed by many years or R&D activity during which prototypes of components or subsystems have been developed. This prototyping phase is now culminating with an evaluation of the prototypes in large-scale tests (approximately called "Data Challenges"). In a period of restricted funding, the expectation is to realize the LHC data acquisition and computing infrastructures by making extensive use of standard and commodity components. The lectures will start with a brief overview of the requirements of the LHC experiments in terms of data acquisition and computing. The different tasks of the experimental data chain will also be explained: data acquisition, selection, storage, processing and analysis. The major trends of the computing and networking industries will then be indicated with pa...

  7. Meta-analysis of the performance variation in broilers experimentally challenged by Eimeria spp.

    Science.gov (United States)

    Kipper, Marcos; Andretta, Ines; Lehnen, Cheila Roberta; Lovatto, Paulo Alberto; Monteiro, Silvia Gonzalez

    2013-09-01

    A meta-analysis was carried out to (1) study the relation of the variation in feed intake and weight gain in broilers infected with Eimeria acervulina, Eimeria maxima, Eimeria tenella, or a Pool of Eimeria species, and (2) to identify and to quantify the effects involved in the infection. A database of articles addressing the experimental infection with Coccidia in broilers was developed. These publications must present results of animal performance (weight gain, feed intake, and feed conversion ratio). The database was composed by 69 publications, totalling around 44 thousand animals. Meta-analysis followed three sequential analyses: graphical, correlation, and variance-covariance. The feed intake of the groups challenged by E. acervulina and E. tenella did not differ (P>0.05) to the control group. However, the feed intake in groups challenged by E. maxima and Pool showed an increase of 8% and 5% (PEimeria species, animal age, sex, and genetic line. In general the age effect is superior to the challenge effect, showing that age at the challenge is important to determine the impact of Eimeria infection. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Behavior of a PCM at Varying Heating Rates: Experimental and Theoretical Study with an Aim at Temperature Moderation in Radionuclide Concrete Encasements

    Science.gov (United States)

    Medved', Igor; Trník, Anton

    2018-07-01

    Phase-change materials (PCMs) can store/release thermal energy within a small temperature range. This is of interest in various industrial applications, for example, in civil engineering (heating/cooling of buildings) or cold storage applications. Another application may be the moderation of temperature increases in concrete encasements of radionuclides during their decay. The phase-change behavior of a material is determined by its heat capacity and the peak it exhibits near a phase change. We analyze the behavior of such peaks for a selected PCM at heating rates varying between 0.1°C\\cdot min^{-1} and 1°C\\cdot min^{-1}, corresponding in real situations to different decay rates of radionuclides. We show that experimentally measured peaks can be plausibly described by an equilibrium theory that enables us to calculate the latent heat and phase-change temperature from experimental data.

  9. Solitons: interactions, theoretical and experimental challenges and perspectives (physics research and technology)

    CERN Document Server

    2013-01-01

    In mathematics and physics, a soliton is a self-reinforcing solitary wave (a wave packet or pulse) that maintains its shape while it travels at constant speed. Solitons are caused by a cancellation of non-linear and dispersive effects in the medium. In this book, the authors discuss the interactions and theoretical and experimental challenges of solitons. Topics include soliton motion of electrons and its physical properties in coupled electron-phonon systems and ionic crystals; soliton excitations and its experimental evidence in molecular crystals; shapes and dynamics of semi-discrete solitons in arrayed and stacked waveguiding systems; ion-acoustic super solitons in plasma; diamond-controlled solitons and turbulence in extracellular matrix and lymphatic dynamics; and non-linear waves in strongly interacting relativistic fluids.

  10. Curing potential of experimental resin composites with systematically varying amount of bioactive glass: Degree of conversion, light transmittance and depth of cure.

    Science.gov (United States)

    Par, Matej; Spanovic, Nika; Bjelovucic, Ruza; Skenderovic, Hrvoje; Gamulin, Ozren; Tarle, Zrinka

    2018-06-17

    The aim of this work was to investigate the curing potential of an experimental resin composite series with the systematically varying amount of bioactive glass 45S5 by evaluating the degree of conversion, light transmittance and depth of cure. Resin composites based on a Bis-GMA/TEGDMA resin with a total filler load of 70 wt% and a variable amount of bioactive glass (0-40 wt%) were prepared. The photoinitiator system was camphorquinone and ethyl-4-(dimethylamino) benzoate. The degree of conversion and light transmittance were measured by Raman spectroscopy and UV-vis spectroscopy, respectively. The depth of cure was evaluated according to the classical ISO 4049 test. The initial introduction of bioactive glass into the experimental series diminished the light transmittance while the further increase in the bioactive glass amount up to 40 wt% caused minor variations with no clear trend. The curing potential of the experimental composites was similar to or better than that of commercial resin composites. However, unsilanized bioactive glass fillers demonstrated the tendency to diminish both the maximum attainable conversion and the curing efficiency at depth. Experimental composite materials containing bioactive glass showed a clinically acceptable degree of conversion and depth of cure. The degree of conversion and depth of cure were diminished by bioactive glass fillers in a dose-dependent manner, although light transmittance was similar among all of the experimental composites containing 5-40 wt% of bioactive glass. Reduced curing potential caused by the bioactive glass has possible consequences on mechanical properties and biocompatibility. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. The Effectiveness of Experimental Diet with Varying Levels of Papain on The Growth Performance, Survival Rate and Feed Utilization of Keureling Fish (Tor tambra

    Directory of Open Access Journals (Sweden)

    Zainal Abidin Muchlisin

    2016-09-01

    Full Text Available The objective of present study was to determine the optimum level of papain in the diet of keureling fish (Tor tambra. The complete random design was utilized in this study. Six levels of papain dosage were tested in triplicates, i.e. 0 (control; 17.5 mg kg-1,  20.0 mg kg-1, 22.5 mg kg-1, 25.0 mg kg-1 and 27.5 mg kg-1 of feed. The experimental fish were fed the experimental diet two times a day at 8 AM and 5 PM at feeding level of 5% body weight for 90 days. The Anova test result showed that papain enzyme  gave a significant effect on the weight gain, daily growth rate, specific growth rate, survival rate, feed conversion ratio and feed efficiency (P<0.05. The Duncan multi-rage test result showed that the higher values for all measured parameters were obtained at the dosage of 27.5 mg kg-1. Therefore, it is concluded that the optimum dosage of papain enzyme for keureling fish was 27.5 mg kg-1 of feed.How to CiteMuchlisin, Z. A., Afrido, F., Murda, T., Fadli, N., Muhammadar, A. A., Jalil, Z., & Yulvizar, C. (2016. The Effectiveness of Experimental Diet with Varying Levels of Papain on The Growth Performance, Survival Rate and Feed Utilization of Keureling Fish (Tor tambra. Biosaintifika: Journal of Biology & Biology Education, 8(2, 172-177.

  12. Seven Ventilators Challenged With Leaks During Neonatal Nasal CPAP: An Experimental Pilot Study.

    Science.gov (United States)

    Drevhammar, Thomas; Nilsson, Kjell; Zetterström, Henrik; Jonsson, Baldvin

    2015-07-01

    Nasal CPAP is the most common respiratory support for neonates. Several factors are considered important for effective treatment, including leaks at the patient interface and the delivery of pressure-stable CPAP. Investigations of pressure stability during leaks should include both the change in the mean delivered CPAP and the pressure variation during each breath. The aim of this study was to examine the response of ventilators delivering nasal CPAP when challenged with leaks at the patient interface. Seven ventilators providing nasal CPAP at 4 cm H2O were challenged with leaks during simulated neonatal breathing. Leak was applied for 15 consecutive breaths at a constant level (1-4 L/min). The 2 aspects of pressure stability were evaluated by measuring the mean delivered CPAP and the amplitude of pressure swings before, during, and after leaks. The ability to maintain the delivered CPAP and the amplitude of pressure swings varied greatly among the 7 ventilators before, during, and after leaks. Four of the ventilators tested have built-in leak compensation. There was no simple relationship between maintaining delivered CPAP during leaks and providing CPAP with low pressure swing amplitude. Maintaining the delivered CPAP and providing this without pressure swings are 2 separate aspects of pressure stability, and investigations concerning the clinical importance of pressure stability should address both aspects. This study also shows that compensation for leaks does not necessarily provide pressure-stable CPAP. Copyright © 2015 by Daedalus Enterprises.

  13. Experimental overview and challenge in strangeness nuclear physics — strangeness in the past and coming decades

    International Nuclear Information System (INIS)

    Imai, Kenichi

    2010-01-01

    A great progress has been made in strangeness nuclear physics in the past decade. Examples are; 1) The "hyperfine" structure of hypernuclei were measured with the Hyperball, and ΛN spin dependent interactions in p-shell hypernuclei were determined. 2) The "complete measurements" of the weak decay of hypernuclei were made and the np ratio puzzle in the non-mesonic decay was solved. 3) The discovery of a clean event of "Lambpha" and determination of its binding energy concluded that the Λ-Λ interaction is weak attractive. However, we still have important questions to be answered in this field, especially in relation with QCD and nuclear physics. For the future strangeness nuclear physics, we have and will have facilities such as JLab, SPring-8, Daphne, J-PARC, FAIR. We discuss experimental challenges in the strangeness nuclear physics and related fields in the next decade. (author)

  14. Seven challenges for model-driven data collection in experimental and observational studies

    Directory of Open Access Journals (Sweden)

    J. Lessler

    2015-03-01

    Full Text Available Infectious disease models are both concise statements of hypotheses and powerful techniques for creating tools from hypotheses and theories. As such, they have tremendous potential for guiding data collection in experimental and observational studies, leading to more efficient testing of hypotheses and more robust study designs. In numerous instances, infectious disease models have played a key role in informing data collection, including the Garki project studying malaria, the response to the 2009 pandemic of H1N1 influenza in the United Kingdom and studies of T-cell immunodynamics in mammals. However, such synergies remain the exception rather than the rule; and a close marriage of dynamic modeling and empirical data collection is far from the norm in infectious disease research. Overcoming the challenges to using models to inform data collection has the potential to accelerate innovation and to improve practice in how we deal with infectious disease threats.

  15. An experimental Toxoplasma gondii dose response challenge model to study therapeutic or vaccine efficacy in cats.

    Directory of Open Access Journals (Sweden)

    Jan B W J Cornelissen

    Full Text Available High numbers of Toxoplasma gondii oocysts in the environment are a risk factor to humans. The environmental contamination might be reduced by vaccinating the definitive host, cats. An experimental challenge model is necessary to quantitatively assess the efficacy of a vaccine or drug treatment. Previous studies have indicated that bradyzoites are highly infectious for cats. To infect cats, tissue cysts were isolated from the brains of mice infected with oocysts of T. gondii M4 strain, and bradyzoites were released by pepsin digestion. Free bradyzoites were counted and graded doses (1000, 100, 50, 10, and 250 intact tissue cysts were inoculated orally into three cats each. Oocysts shed by these five groups of cats were collected from faeces by flotation techniques, counted microscopically and estimated by real time PCR. Additionally, the number of T. gondii in heart, tongue and brains were estimated, and serology for anti T. gondii antibodies was performed. A Beta-Poisson dose-response model was used to estimate the infectivity of single bradyzoites and linear regression was used to determine the relation between inoculated dose and numbers of oocyst shed. We found that real time PCR was more sensitive than microscopic detection of oocysts, and oocysts were detected by PCR in faeces of cats fed 10 bradyzoites but by microscopic examination. Real time PCR may only detect fragments of T. gondii DNA without the presence of oocysts in low doses. Prevalence of tissue cysts of T. gondii in tongue, heart and brains, and anti T. gondii antibody concentrations were all found to depend on the inoculated bradyzoite dose. The combination of the experimental challenge model and the dose response analysis provides a suitable reference for quantifying the potential reduction in human health risk due to a treatment of domestic cats by vaccination or by therapeutic drug application.

  16. Estimation of time-varying pollutant emission rates in a ventilated enclosure: inversion of a reduced model obtained by experimental application of the modal identification method

    International Nuclear Information System (INIS)

    Girault, M; Maillet, D; Bonthoux, F; Galland, B; Martin, P; Braconnier, R; Fontaine, J R

    2008-01-01

    A method is proposed for the estimation of time-varying emission rates of pollutant sources in a ventilated enclosure, through the resolution of an inverse forced convection problem. Unsteady transport–diffusion of the pollutant is considered, with the assumption of a stationary velocity field remaining unchanged during emission (passive contaminant). The pollutant transport equation is therefore linear with respect to concentration. The source's location is also supposed to be known. As the first step, a reduced model (RM) linking concentrations at a set of control points to emission rates of sources is identified from experimental data by using the modal identification method (MIM). This parameter estimation problem uses transient contaminant concentration measurements made at control points inside the ventilated enclosure, corresponding to increasing and decreasing steps of emission rates. Such experimental modelling allows us to avoid dealing with a CFD code involving turbulence modelling and to get rid of uncertainties about sensors position. In a second step, the identified RM is used to solve an inverse forced convection problem: from contaminant concentration measured at the same control points, rates of sources emitting simultaneously are estimated with a sequential in time algorithm using future time steps

  17. Experimental facility for development of high-temperature reactor technology: instrumentation needs and challenges

    Directory of Open Access Journals (Sweden)

    Sabharwall Piyush

    2015-01-01

    Full Text Available A high-temperature, multi-fluid, multi-loop test facility is under development at the Idaho National Laboratory for support of thermal hydraulic materials, and system integration research for high-temperature reactors. The experimental facility includes a high-temperature helium loop, a liquid salt loop, and a hot water/steam loop. The three loops will be thermally coupled through an intermediate heat exchanger (IHX and a secondary heat exchanger (SHX. Research topics to be addressed include the characterization and performance evaluation of candidate compact heat exchangers such as printed circuit heat exchangers (PCHEs at prototypical operating conditions. Each loop will also include an interchangeable high-temperature test section that can be customized to address specific research issues associated with each working fluid. This paper also discusses needs and challenges associated with advanced instrumentation for the multi-loop facility, which could be further applied to advanced high-temperature reactors. Based on its relevance to advanced reactor systems, the new facility has been named the Advanced Reactor Technology Integral System Test (ARTIST facility. A preliminary design configuration of the ARTIST facility will be presented with the required design and operating characteristics of the various components. The initial configuration will include a high-temperature (750 °C, high-pressure (7 MPa helium loop thermally integrated with a molten fluoride salt (KF-ZrF4 flow loop operating at low pressure (0.2 MPa, at a temperature of ∼450 °C. The salt loop will be thermally integrated with the steam/water loop operating at PWR conditions. Experiment design challenges include identifying suitable materials and components that will withstand the required loop operating conditions. The instrumentation needs to be highly accurate (negligible drift in measuring operational data for extended periods of times, as data collected will be

  18. Experimental facility for development of high-temperature reactor technology: instrumentation needs and challenges - 15066

    International Nuclear Information System (INIS)

    Sabharwall, P.; O'Brien, J.E.; Yoon, S.J.; Sun, X.

    2015-01-01

    A high-temperature, multi-fluid, multi-loop test facility is under development at the Idaho National Laboratory for support of thermal hydraulic, materials, and system integration research for high-temperature reactors. The experimental facility includes a high-temperature helium loop, a liquid salt loop, and a hot water/steam loop. The 3 loops will be thermally coupled through an intermediate heat exchanger (IHX) and a secondary heat exchanger (SHX). Research topics to be addressed include the characterization and performance evaluation of candidate compact heat exchangers such as printed circuits heat exchangers (PCHEs) at prototypical operating conditions. Each loop will also include an interchangeable high-temperature test section that can be customized to address specific research issues associated with each working fluid. This paper also discusses needs and challenges associated with advanced instrumentation for the multi-loop facility, which could be further applied to advanced high-temperature reactors. Based on its relevance to advanced reactor systems, the new facility has been named the Advanced Reactor Technology Integrated System Test (ARTIST) facility. A preliminary design configuration of the ARTIST facility will be presented with the required design and operating characteristics of the various components. The initial configuration will include a high-temperature (750 C. degrees), high-pressure (7 MPa) helium loop thermally integrated with a molten fluoride salt (KF-ZrF 4 ) flow loop operating at low pressure (0.2 MPa), at a temperature of ∼ 450 C. degrees. The salt loop will be thermally integrated with the steam/water loop operating at PWR conditions. Experiment design challenges include identifying suitable materials and components that will withstand the required loop operating conditions. The instrumentation needs to be highly accurate (negligible drift) in measuring operational data for extended periods of times, as data collected will be

  19. Outcomes of antiretroviral treatment program in Ethiopia: Retention of patients in care is a major challenge and varies across health facilities

    Directory of Open Access Journals (Sweden)

    Kloos Helmut

    2011-04-01

    major challenge and varies across health facilities with high, medium and low retention rates. We therefore recommend further studies to understand the organization of care in health facilities with high, medium and low retention rates. It is also imperative that early initiation of patients on ART is taken seriously as more than 79% of the patients had baseline CD4-cell counts less than 200 cells per micro-liter of blood. Finally, we recommend that the shift to second-line ART might be too low and warrants close monitoring.

  20. An Experimental Study of Shear-Dominated Failure in the 2013 Sandia Fracture Challenge Specimen

    Energy Technology Data Exchange (ETDEWEB)

    Corona, Edmundo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Deibler, Lisa Anne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Reedlunn, Benjamin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ingraham, Mathew Duffy [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Williams, Shelley [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-04-01

    This report presents an experimental study motivated by results obtained during the 2013 Sandia Fracture Challenge. The challenge involved A286 steel, shear-dominated compression specimens whose load-deflection response contained a load maximum fol- lowed by significant displacement under decreasing load, ending with a catastrophic fracture. Blind numerical simulations deviated from the experiments well before the maximum load and did not predict the failure displacement. A series of new tests were conducted on specimens machined from the original A286 steel stock to learn more about the deformation and failure processes in the specimen and potentially improve future numerical simulations. The study consisted of several uniaxial tension tests to explore anisotropy in the material, and a set of new tests on the compression speci- men. In some compression specimen tests, stereo digital image correlation (DIC) was used to measure the surface strain fields local to the region of interest. In others, the compression specimen was loaded to a given displacement prior to failure, unloaded, sectioned, and imaged under the microscope to determine when material damage first appeared and how it spread. The experiments brought the following observations to light. The tensile tests revealed that the plastic response of the material is anisotropic. DIC during the shear- dominated compression tests showed that all three in-plane surface strain components had maxima in the order of 50% at the maximum load. Sectioning of the specimens revealed no signs of material damage at the point where simulations deviated from the experiments. Cracks and other damage did start to form approximately when the max- imum load was reached, and they grew as the load decreased, eventually culminating in catastrophic failure of the specimens. In addition to the steel specimens, a similar study was carried out for aluminum 7075-T651 specimens. These specimens achieved much lower loads and displacements

  1. The Evolution of Chemical High-Throughput Experimentation To Address Challenging Problems in Pharmaceutical Synthesis.

    Science.gov (United States)

    Krska, Shane W; DiRocco, Daniel A; Dreher, Spencer D; Shevlin, Michael

    2017-12-19

    The structural complexity of pharmaceuticals presents a significant challenge to modern catalysis. Many published methods that work well on simple substrates often fail when attempts are made to apply them to complex drug intermediates. The use of high-throughput experimentation (HTE) techniques offers a means to overcome this fundamental challenge by facilitating the rational exploration of large arrays of catalysts and reaction conditions in a time- and material-efficient manner. Initial forays into the use of HTE in our laboratories for solving chemistry problems centered around screening of chiral precious-metal catalysts for homogeneous asymmetric hydrogenation. The success of these early efforts in developing efficient catalytic steps for late-stage development programs motivated the desire to increase the scope of this approach to encompass other high-value catalytic chemistries. Doing so, however, required significant advances in reactor and workflow design and automation to enable the effective assembly and agitation of arrays of heterogeneous reaction mixtures and retention of volatile solvents under a wide range of temperatures. Associated innovations in high-throughput analytical chemistry techniques greatly increased the efficiency and reliability of these methods. These evolved HTE techniques have been utilized extensively to develop highly innovative catalysis solutions to the most challenging problems in large-scale pharmaceutical synthesis. Starting with Pd- and Cu-catalyzed cross-coupling chemistry, subsequent efforts expanded to other valuable modern synthetic transformations such as chiral phase-transfer catalysis, photoredox catalysis, and C-H functionalization. As our experience and confidence in HTE techniques matured, we envisioned their application beyond problems in process chemistry to address the needs of medicinal chemists. Here the problem of reaction generality is felt most acutely, and HTE approaches should prove broadly enabling

  2. Development of the Digestive System-Experimental Challenges and Approaches of Infant Lipid Digestion.

    Science.gov (United States)

    Abrahamse, Evan; Minekus, Mans; van Aken, George A; van de Heijning, Bert; Knol, Jan; Bartke, Nana; Oozeer, Raish; van der Beek, Eline M; Ludwig, Thomas

    2012-12-01

    At least during the first 6 months after birth, the nutrition of infants should ideally consist of human milk which provides 40-60 % of energy from lipids. Beyond energy, human milk also delivers lipids with a specific functionality, such as essential fatty acids (FA), phospholipids, and cholesterol. Healthy development, especially of the nervous and digestive systems, depends fundamentally on these. Epidemiological data suggest that human milk provides unique health benefits during early infancy that extend to long-lasting benefits. Preclinical findings show that qualitative changes in dietary lipids, i.e., lipid structure and FA composition, during early life may contribute to the reported long-term effects. Little is known in this respect about the development of digestive function and the digestion and absorption of lipids by the newborn. This review gives a detailed overview of the distinct functionalities that dietary lipids from human milk and infant formula provide and the profound differences in the physiology and biochemistry of lipid digestion between infants and adults. Fundamental mechanisms of infant lipid digestion can, however, almost exclusively be elucidated in vitro. Experimental approaches and their challenges are reviewed in depth.

  3. Efficacy of Mycoplasma hyopneumoniae vaccination before and at weaning against experimental challenge infection in pigs.

    Science.gov (United States)

    Arsenakis, Ioannis; Panzavolta, Luca; Michiels, Annelies; Del Pozo Sacristán, Rubén; Boyen, Filip; Haesebrouck, Freddy; Maes, Dominiek

    2016-03-29

    Commercial bacterins are widely used at weaning to control Mycoplasma hyopneumoniae infections in pigs. However, it is not known whether the efficacy of vaccinating against M. hyopneumoniae can be influenced by the weaning process when vaccination is applied at the day of weaning. The present study assessed the efficacy of a single M. hyopneumoniae vaccination (Ingelvac MycoFLEX®) three days before weaning (V1) or at weaning (V2) against experimental challenge infection. Four weeks after vaccination, groups V1 and V2 (n = 20 pigs each) and a non-vaccinated, positive control group (PCG) (n = 20) were endotracheally inoculated with a virulent M. hyopneumoniae field strain. Five pigs were used as a negative control group. All pigs were euthanized 5 weeks after challenge. The main parameters investigated included macroscopic and histopathological lung lesions at necropsy, immunofluorescence (IF) staining and quantitative real-time PCR (qPCR) on broncho-alveolar lavage (BAL) fluid for quantifying M. hyopneumoniae. The average macroscopic lung lesion scores in groups V1, V2 and PCG were 0.54, 0.88 and 1.04, respectively (P > 0.05). The average lymphohistiocytic infiltration scores in groups V1, V2 and PCG were 2.95, 3.16 and 3.61, respectively (P 0.05), the qPCR values were: V1 = 10(2.94), V2 = 10(2.76) and PCG = 10(3.23) (P > 0.05). All pigs of the negative control group remained negative throughout the study. Both vaccinated groups had lower numbers of macroscopic and histopathological lung lesions, and lower numbers of M. hyopneumoniae organisms in the BAL fluid compared to the PCG. However, no firm conclusions could be made on whether weaning negatively influences the efficacy of M. hyopneumoniae vaccination, since significant differences between the treatment groups were only obtained for the histopathological lung lesions. This could be attributed to the fact that milder macroscopic lung lesions were produced in the inoculated pigs, when compared to previous

  4. Early host response in the mammary gland after experimental Streptococcus uberis challenge in heifers.

    Science.gov (United States)

    de Greeff, Astrid; Zadoks, Ruth; Ruuls, Lisette; Toussaint, Mathilda; Nguyen, Thi Kim Anh; Downing, Alison; Rebel, Johanna; Stockhofe-Zurwieden, Norbert; Smith, Hilde

    2013-06-01

    Streptococcus uberis is a highly prevalent causative agent of bovine mastitis, which leads to large economic losses in the dairy industry. The aim of this study was to examine the host response during acute inflammation after experimental challenge with capsulated Strep. uberis. Gene expression in response to Strep. uberis was compared between infected and control quarters in 3 animals. All quarters (n=16) were sampled at 16 different locations. Microarray data showed that 239 genes were differentially expressed between infected and control quarters. No differences in gene expression were observed between the different locations. Microarray data were confirmed for several genes using quantitative PCR analysis. Genes differentially expressed due to early Strep. uberis mastitis represented several stages of the process of infection: (1) pathogen recognition; (2) chemoattraction of neutrophils; (3) tissue repair mechanisms; and (4) bactericidal activity. Three different pathogen recognition genes were induced: ficolins, lipopolysaccharide binding protein, and toll-like receptor 2. Calgranulins were found to be the most strongly upregulated genes during early inflammation. By histology and immunohistochemistry, we demonstrated that changes in gene expression in response to Strep. uberis were induced both in infiltrating somatic milk cells and in mammary epithelial cells, demonstrating that the latter cell type plays a role in milk production as well as immune responsiveness. Given the rapid development of inflammation or mastitis after infection, early diagnosis of (Strep. uberis) mastitis is required for prevention of disease and spread of the pathogen. Insight into host responses could help to design immunomodulatory therapies to dampen inflammation after (early) diagnosis of Strep. uberis mastitis. Future research should focus on development of these early diagnostics and immunomodulatory components for mastitis treatment. Copyright © 2013 American Dairy Science

  5. Comparison of abortion and infection after experimental challenge of pregnant bison and cattle with Brucella abortus strain 2308

    Science.gov (United States)

    A comparative study was conducted using data from naive bison (n=45) and cattle (n=46) from 8 and 6 studies, respectively, in which a standardized Brucella abortus strain 2308 experimental challenge was administered. The incidence of abortion, fetal infection, uterine or mammary infection, or infec...

  6. Does the Effect of Micro-Environmental Factors on a Street's Appeal for Adults' Bicycle Transport Vary across Different Macro-Environments? An Experimental Study.

    Science.gov (United States)

    Mertens, Lieze; Van Cauwenberg, Jelle; Ghekiere, Ariane; Van Holle, Veerle; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Nasar, Jack; Van de Weghe, Nico; Van Dyck, Delfien

    2015-01-01

    Characteristics of the physical environment can be classified into two broad categories: macro- ("raw" urban planning features influenced on a regional level) and micro- (features specifically within a streetscape influenced on a neighborhood level) environmental factors. In urban planning applications, it is more feasible to modify conditions at the neighborhood level than at the regional level. Yet for the promotion of bicycle transport we need to know whether relationships between micro-environmental factors and bicycle transport depend on different types of macro-environments. This study aimed to identify whether the effect of three micro-environmental factors (i.e., evenness of the cycle path surface, speed limits and type of separation between cycle path and motorized traffic) on the street's appeal for adults' bicycle transport varied across three different macro-environments (i.e., low, medium and high residential density street). In total, 389 middle-aged adults completed a web-based questionnaire consisting of socio-demographic characteristics and a series of choice tasks with manipulated photographs, depicting two possible routes to cycle along. Conjoint analysis was used to analyze the data. Although the magnitude of the overall effects differed, in each macro-environment (i.e., low, medium and high residential density), middle-aged adults preferred a speed limit of 30 km/h, an even cycle path surface and a hedge as separation between motorized traffic and the cycle path compared to a speed limit of 50 or 70 km/h, a slightly uneven or uneven cycle path surface and a curb as separation or no separation between motorized traffic and the cycle path. Our results suggest that irrespective of the macro-environment, the same micro-environmental factors are preferred in middle-aged adults concerning the street's appeal for bicycle transport. The controlled environment simulations in the experimental choice task have the potential to inform real life

  7. Does the Effect of Micro-Environmental Factors on a Street’s Appeal for Adults’ Bicycle Transport Vary across Different Macro-Environments? An Experimental Study

    Science.gov (United States)

    Mertens, Lieze; Van Cauwenberg, Jelle; Ghekiere, Ariane; Van Holle, Veerle; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Nasar, Jack; Van de Weghe, Nico; Van Dyck, Delfien

    2015-01-01

    Background Characteristics of the physical environment can be classified into two broad categories: macro- (“raw” urban planning features influenced on a regional level) and micro- (features specifically within a streetscape influenced on a neighborhood level) environmental factors. In urban planning applications, it is more feasible to modify conditions at the neighborhood level than at the regional level. Yet for the promotion of bicycle transport we need to know whether relationships between micro-environmental factors and bicycle transport depend on different types of macro-environments. This study aimed to identify whether the effect of three micro-environmental factors (i.e., evenness of the cycle path surface, speed limits and type of separation between cycle path and motorized traffic) on the street’s appeal for adults’ bicycle transport varied across three different macro-environments (i.e., low, medium and high residential density street). Methods In total, 389 middle-aged adults completed a web-based questionnaire consisting of socio-demographic characteristics and a series of choice tasks with manipulated photographs, depicting two possible routes to cycle along. Conjoint analysis was used to analyze the data. Results Although the magnitude of the overall effects differed, in each macro-environment (i.e., low, medium and high residential density), middle-aged adults preferred a speed limit of 30 km/h, an even cycle path surface and a hedge as separation between motorized traffic and the cycle path compared to a speed limit of 50 or 70 km/h, a slightly uneven or uneven cycle path surface and a curb as separation or no separation between motorized traffic and the cycle path. Conclusions Our results suggest that irrespective of the macro-environment, the same micro-environmental factors are preferred in middle-aged adults concerning the street’s appeal for bicycle transport. The controlled environment simulations in the experimental choice task

  8. Does the Effect of Micro-Environmental Factors on a Street's Appeal for Adults' Bicycle Transport Vary across Different Macro-Environments? An Experimental Study.

    Directory of Open Access Journals (Sweden)

    Lieze Mertens

    Full Text Available Characteristics of the physical environment can be classified into two broad categories: macro- ("raw" urban planning features influenced on a regional level and micro- (features specifically within a streetscape influenced on a neighborhood level environmental factors. In urban planning applications, it is more feasible to modify conditions at the neighborhood level than at the regional level. Yet for the promotion of bicycle transport we need to know whether relationships between micro-environmental factors and bicycle transport depend on different types of macro-environments. This study aimed to identify whether the effect of three micro-environmental factors (i.e., evenness of the cycle path surface, speed limits and type of separation between cycle path and motorized traffic on the street's appeal for adults' bicycle transport varied across three different macro-environments (i.e., low, medium and high residential density street.In total, 389 middle-aged adults completed a web-based questionnaire consisting of socio-demographic characteristics and a series of choice tasks with manipulated photographs, depicting two possible routes to cycle along. Conjoint analysis was used to analyze the data.Although the magnitude of the overall effects differed, in each macro-environment (i.e., low, medium and high residential density, middle-aged adults preferred a speed limit of 30 km/h, an even cycle path surface and a hedge as separation between motorized traffic and the cycle path compared to a speed limit of 50 or 70 km/h, a slightly uneven or uneven cycle path surface and a curb as separation or no separation between motorized traffic and the cycle path.Our results suggest that irrespective of the macro-environment, the same micro-environmental factors are preferred in middle-aged adults concerning the street's appeal for bicycle transport. The controlled environment simulations in the experimental choice task have the potential to inform real life

  9. Arterial Spin Labeling (ASL) fMRI: advantages, theoretical constrains, and experimental challenges in neurosciences.

    Science.gov (United States)

    Borogovac, Ajna; Asllani, Iris

    2012-01-01

    Cerebral blood flow (CBF) is a well-established correlate of brain function and therefore an essential parameter for studying the brain at both normal and diseased states. Arterial spin labeling (ASL) is a noninvasive fMRI technique that uses arterial water as an endogenous tracer to measure CBF. ASL provides reliable absolute quantification of CBF with higher spatial and temporal resolution than other techniques. And yet, the routine application of ASL has been somewhat limited. In this review, we start by highlighting theoretical complexities and technical challenges of ASL fMRI for basic and clinical research. While underscoring the main advantages of ASL versus other techniques such as BOLD, we also expound on inherent challenges and confounds in ASL perfusion imaging. In closing, we expound on several exciting developments in the field that we believe will make ASL reach its full potential in neuroscience research.

  10. Primary infection protects pigs against re-infection with Lawsonia intracellularis in experimental challenge studies

    DEFF Research Database (Denmark)

    Riber, Ulla; Hvass, Henriette Cordes; Boutrup, Torsten Snogdal

    2011-01-01

    In two separate trials previous termpigsnext term were experimentally infected with previous termLawsonia intracellularisnext term at 5–6 weeks of age followed by antibiotic treatment and resolution of the previous termprimary infection and then renext term-inoculated at 12–13 weeks of age. A tre...

  11. Challenges in Data Collection and Analysis in Multi-National Experimentation

    Science.gov (United States)

    2007-06-01

    sampling of personnel when individual interviews would be labor intensive and time consuming. Ideally surveys contribute to the cognitive aspect of...the experimental data for the data collection plan. In addition to gaining data concerning the cognitive aspect , surveys can be used when no other

  12. Prevention of hepatocellular carcinoma: potential targets, experimental models, and clinical challenges

    Science.gov (United States)

    Hoshida, Yujin; Fuchs, Bryan C.; Tanabe, Kenneth K.

    2013-01-01

    Chronic fibrotic liver diseases such as viral hepatitis eventually develop liver cirrhosis, which causes occurrence of hepatocellular carcinoma (HCC). Given the limited therapeutic efficacy in advanced HCC, prevention of HCC development could be an effective strategy for improving patient prognosis. However, there is still no established therapy to meet the goal. Studies have elucidated a wide variety of molecular mechanisms and signaling pathways involved in HCC development. Genetically-engineered or chemically-treated experimental models of cirrhosis and HCC have been developed and shown their potential value in investigating molecular therapeutic targets and diagnostic biomarkers for HCC prevention. In this review, we overview potential targets of prevention and currently available experimental models, and discuss strategies to translate the findings into clinical practice. PMID:22873223

  13. The experimental challenge of virtual compton scattering above 8 GeV

    International Nuclear Information System (INIS)

    Pierre Bertin; Yves Roblin; Charles Hyde-Wright

    1999-01-01

    We discuss the experimental issues confronting measurements of the Virtual Compton Scattering (VCS) reaction ep->ep gamma with electron beam energies 6-30 GeV. We specifically address the kinematics of Deeply Virtual Compton Scattering (Deep Inelastic Scattering, with coincident detection of the exclusive real photon nearly parallel to the virtual photon direction) and large transverse momentum VCS (High energy VCS of arbitrary Q 2 , and the recoil proton emitted with high momentum transverse to the virtual photon direction). We discuss the experimental equipment necessary for these measurements. For the DVCS, we emphasize the importance of the Bethe-Heitler-Compton interference terms that can be measured with the electron-positron (beam charge) asymmetry, and the electron beam helicity asymmetry

  14. Mixed reality learning spaces for collaborative experimentation: A challenge for engineering education and training

    Directory of Open Access Journals (Sweden)

    Dieter Müller

    2007-10-01

    Full Text Available Although the vast majority of research in human-computer interaction involves only our senses of sight and hearing, with sporadic forays into touch, future laboratories used in engineering education will mostly benefit from developments beyond video and sound. Tangible and embedded interaction, augmented and mixed reality characterizes ultimate technologies for further applications in collaborative remote engineering and lab work. This paper presents our latest research to facilitate collaborative experimentation with such innovative technologies. Our vision is a collaborative learning space, which involves an amalgam of real, virtual and remote lab tools to support a wide spectrum of simple and complex, concrete and abstract, safe and dangerous experimentation settings. We will review related concepts and discuss lessons learned from our research and prototype development. Recent work involves the use of mixed reality (as opposed to ‘pure’ virtual reality techniques to support seamless collaborative work between remote sites. We describe this and identify areas for future research.

  15. Effect of preventive Chlamydia abortus vaccination in offspring development in sheep challenged experimentally

    Directory of Open Access Journals (Sweden)

    Teresa García-Seco

    2016-08-01

    Full Text Available Ovine enzootic abortion, caused by Chlamydia abortus, leads to important economic losses worldwide. In addition to reproductive failures, infection may impact lamb growth during the first weeks after birth, yet this effect has not been well characterized. Vaccination can help to control the disease but variable efficacy values have been described, possibly related with factors associated with the host, the vaccine, the parameter used for efficacy determination and the challenge conditions. In this context, we evaluated the efficacy of an inactivated standard commercial vaccine and a 1/2 diluted dose in pregnant sheep challenged with C. abortus by examining multiple indicators ofvaccine effect (including incidence of reproductive failures, bacterial excretion, and evolution of weight gain of viable lambs during the first month of life. Three groups of ewes [control non-vaccinated, C (n = 18; vaccinated with standard dose, SV (n = 16 and vaccinated with 1/2 dose, DV (n = 17], were challenged approximately 90 days post-mating and tested using direct PCR (tissue samples and vaginal swabs and ELISA (serum until 31 days post-reproductive outcome. There were not significant differences in the proportions of reproductive failures or bacterial shedding after birth/abortion regardless the vaccination protocol. However, a beneficial effect of vaccination on offspring growth was detected in both vaccinated groups compared with the controls, with a mean increase in weight measured at 30 days of life of 1.5 and 2.5 Kg (p = 0.056 and an increase in the geometric mean of the daily gain of 8.4 and 9.7% in lambs born from DV and SV ewes compared to controls, respectively. Our results demonstrate the effect of an inactivated vaccine in the development of the offspring of C. abortus-infected ewes at a standard and a diluted dose, an interesting finding given the difficulty in achieving sufficient antigen concentration in the production of EAE-commercial vaccines.

  16. Physics Goals and Experimental Challenges of the Proton-Proton High-Luminosity Operation of the LHC

    CERN Document Server

    Campana, Pierluigi; Wells, Pippa

    2016-01-01

    The completion of Run 1 of the CERN Large Hadron Collider has seen the discovery of the Higgs boson and an unprecedented number of precise measurements of the Standard Model, while Run 2 operation has just started to provide first data at higher energy. Upgrades of the LHC to high luminosity (HL-LHC) and the experiments (ATLAS, CMS, ALICE and LHCb) will exploit the full potential of the collider to discover and explore new physics beyond the Standard Model. In this article, the experimental challenges and the physics opportunities in proton-proton collisions at the HL-LHC are reviewed.

  17. Physics Goals and Experimental Challenges of the Proton-Proton High-Luminosity Operation of the LHC

    Science.gov (United States)

    Campana, P.; Klute, M.; Wells, P. S.

    2016-10-01

    The completion of Run 1 of the Large Hadron Collider (LHC) at CERN has seen the discovery of the Higgs boson and an unprecedented number of precise measurements of the Standard Model, and Run 2 has begun to provide the first data at higher energy. The high-luminosity upgrade of the LHC (HL-LHC) and the four experiments (ATLAS, CMS, ALICE, and LHCb) will exploit the full potential of the collider to discover and explore new physics beyond the Standard Model. We review the experimental challenges and the physics opportunities in proton-proton collisions at the HL-LHC.

  18. Effect of Preventive Chlamydia abortus Vaccination in Offspring Development in Sheep Challenged Experimentally.

    Science.gov (United States)

    García-Seco, Teresa; Pérez-Sancho, Marta; Salinas, Jesús; Navarro, Alejandro; Díez-Guerrier, Alberto; García, Nerea; Pozo, Pilar; Goyache, Joaquín; Domínguez, Lucas; Álvarez, Julio

    2016-01-01

    Ovine enzootic abortion, caused by Chlamydia abortus, leads to important economic losses worldwide. In addition to reproductive failures, infection may impact lamb growth during the first weeks after birth, yet this effect has not been well characterized. Vaccination can help to control the disease but variable efficacy values have been described, possibly related with factors associated with the host, the vaccine, the parameter used for efficacy determination, and the challenge conditions. In this context, we evaluated the efficacy of an inactivated standard commercial vaccine and a 1/2 diluted dose in pregnant sheep challenged with C. abortus by examining multiple indicators of vaccine effect (including incidence of reproductive failures, bacterial excretion, and evolution of weight gain of viable lambs during the first month of life). Three groups of ewes [control non-vaccinated, C (n = 18); vaccinated with standard dose, SV (n = 16); and vaccinated with 1/2 dose, DV (n = 17)], were challenged approximately 90 days post-mating and tested using direct PCR (tissue samples and vaginal swabs) and ELISA (serum) until 31 days post-reproductive outcome. There were not significant differences in the proportions of reproductive failures or bacterial shedding after birth/abortion regardless the vaccination protocol. However, a beneficial effect of vaccination on offspring growth was detected in both vaccinated groups compared with the controls, with a mean increase in weight measured at 30 days of life of 1.5 and 2.5 kg (p = 0.056) and an increase in the geometric mean of the daily gain of 8.4 and 9.7% in lambs born from DV and SV ewes compared with controls, respectively. Our results demonstrate the effect of an inactivated vaccine in the development of the offspring of C. abortus-infected ewes at a standard and a diluted dose, an interesting finding given the difficulty in achieving sufficient antigen concentration in the production of enzootic

  19. The front end electronics of the NA62 Gigatracker: challenges, design and experimental measurements

    Science.gov (United States)

    Noy, M.; Aglieri Rinella, G.; Ceccucci, A.; Dellacasa, G.; Fiorini, M.; Garbolino, S.; Jarron, P.; Kaplon, J.; Kluge, A.; Marchetto, F.; Martin, E.; Mazza, G.; Martoiu, S.; Morel, M.; Perktold, L.; Rivetti, A.; Tiuraniemi, S.

    2011-06-01

    The beam spectrometer of the NA62 experiment consists of 3 Gigatracker (GTK) stations. Each station comprises a pixel detector of 16 cm active area made of an assembly of 10 readout ASICs bump bonded to a 200 μm thick pixel silicon sensor, comprising 18000 pixels of 300 μm×300 μm. The main challenge of the NA62 pixel GTK station is the combination of an extremely high kaon/pion beam rate, where the intensity in the center of the beam reaches up to 1.5 Mhit s mm together with an extreme time resolution of 100 ps. To date, it is the first silicon tracking system with this time resolution. To face this challenge, the pixel analogue front end has been designed with a peaking time of 4 ns, with a planar silicon sensor operating up to 300 V over depletion. Moreover, the radiation level is severe, 2×10 1 MeV n cm per year of operation. Easy replacement of the GTK stations is foreseen as a design requirement. The amount of material of a single station should also be less than 0.5% X to minimize the background, which imposes strong constraints on the mechanics and the cooling system. We report upon the design and architecture of the 2 prototype demonstrator chips both designed in 130 nm CMOS technology, one with a constant fraction discriminator and the time stamp digitisation in each pixel (In-Pixel), and the other with a time-over-threshold discriminator and the processing of the time stamp located in the End of Column (EoC) region at the chip periphery. Some preliminary results are presented.

  20. Experimental models in predicting topical antifungal efficacy: practical aspects and challenges.

    Science.gov (United States)

    Lai, J; Maibach, H I

    2009-01-01

    What are efficient screening models for improved topical antifungals? The use of minimum inhibitory concentrations (MICs) as one such parameter is discussed; we focus on the use of animal membranes for in vitro testing while highlighting the pros and cons of each model, exploring alternatives and discussing the importance of data transferability to humans and the influence of penetration kinetics in topical antifungal efficacy. Ultimately, the gold standard of testing is in vivo in humans; however, initiating with human testing, especially for novel topical antifungal agents, may be impractical, which is why we seek the ideal experimental model that most closely mimics human skin. We conclude that the pig may be an appropriate model membrane for topical antifungal testing based on its similarities in anatomical structure, physiology and permeation to human skin. Most importantly, pig and human skins appear equally permeable to several antifungals in prior in vitro and in vivo work. We do not discuss all prior work but highlight important issues in designing the protocol and parameters of the ideal experimental model for topical antifungals. Copyright 2009 S. Karger AG, Basel.

  1. Challenges in experimental fatigue testing of glassfibre reinforced polymer matrix composites for wind turbine industry

    DEFF Research Database (Denmark)

    Sjøgreen, Freja Naima; Goutianos, Stergios

    to introduce the load through shear stresses without getting high shear stress concentrations causing shear failure in the gripping region. In compression-compression testing, the load introduction also has to be considered to avoid failure in the gripping region e.g. by transferring part of the load through...... the specimen’s ends and partly through shear stresses. The gauge length of the specimen is limited by the Euler buckling limit. Work on optimizing the specimen geometry and the experimental setup has been done on tension-tension fatigue by Korkiakosky et al. (2016) and on compressioncompression fatigue...... on the variance of the fatigue test results on composite materials specimens. Options to improve the design limits of the composite materials are either to improve the material quality, or to decrease the variance of the fatigue test results by improving the fatigue test methods. In recent years, extensive work...

  2. Experimental approach to interaction physics challenges of the shock ignition scheme using short pulse lasers.

    Science.gov (United States)

    Goyon, C; Depierreux, S; Yahia, V; Loisel, G; Baccou, C; Courvoisier, C; Borisenko, N G; Orekhov, A; Rosmej, O; Labaune, C

    2013-12-06

    An experimental program was designed to study the most important issues of laser-plasma interaction physics in the context of the shock ignition scheme. In the new experiments presented in this Letter, a combination of kilojoule and short laser pulses was used to study the laser-plasma coupling at high laser intensities for a large range of electron densities and plasma profiles. We find that the backscatter is dominated by stimulated Brillouin scattering with stimulated Raman scattering staying at a limited level. This is in agreement with past experiments using long pulses but laser intensities limited to 2×10(15)  W/cm2, or short pulses with intensities up to 5×10(16)  W/cm2 as well as with 2D particle-in-cell simulations.

  3. New Issues for New Methods: Ethical and Editorial Challenges for an Experimental Philosophy.

    Science.gov (United States)

    Polonioli, Andrea

    2017-08-01

    This paper examines a constellation of ethical and editorial issues that have arisen since philosophers started to conduct, submit and publish empirical research. These issues encompass concerns over responsible authorship, fair treatment of human subjects, ethicality of experimental procedures, availability of data, unselective reporting and publishability of research findings. This study aims to assess whether the philosophical community has as yet successfully addressed such issues. To do so, the instructions for authors, submission process and published research papers of 29 main journals in philosophy have been considered and analyzed. In light of the evidence reported here, it is argued that the philosophical community has as yet failed to properly tackle such issues. The paper also delivers some recommendations for authors, reviewers and editors in the field.

  4. The Promises and Challenges of Ecological Momentary Assessment in Schizophrenia: Development of an Initial Experimental Protocol

    Directory of Open Access Journals (Sweden)

    Brandon A. Gaudiano

    2015-07-01

    Full Text Available Severe mental illnesses, including schizophrenia and other psychotic-spectrum disorders, are a major cause of disability worldwide. Although efficacious pharmacological and psychosocial interventions have been developed for treating patients with schizophrenia, relapse rates are high and long-term recovery remains elusive for many individuals. Furthermore, little is still known about the underlying mechanisms of these illnesses. Thus, there is an urgent need to better understand the contextual factors that contribute to psychosis so that they can be better targeted in future interventions. Ecological Momentary Assessment (EMA is a dynamic procedure that permits the measurement of variables in natural settings in real-time through the use of brief assessments delivered via mobile electronic devices (i.e., smartphones. One advantage of EMA is that it is less subject to retrospective memory biases and highly sensitive to fluctuating environmental factors. In the current article, we describe the research-to-date using EMA to better understand fluctuating symptoms and functioning in patients with schizophrenia and other psychotic disorders and potential applications to treatment. In addition, we describe a novel EMA protocol that we have been employing to study the outcomes of patients with schizophrenia following a hospital discharge. We also report the lessons we have learned thus far using EMA methods in this challenging clinical population.

  5. Vaccination against Louping Ill Virus Protects Goats from Experimental Challenge with Spanish Goat Encephalitis Virus.

    Science.gov (United States)

    Salinas, L M; Casais, R; García Marín, J F; Dalton, K P; Royo, L J; Del Cerro, A; Gayo, E; Dagleish, M P; Alberdi, P; Juste, R A; de la Fuente, J; Balseiro, A

    2017-05-01

    Spanish goat encephalitis virus (SGEV) is a recently described member of the genus Flavivirus belonging to the tick-borne encephalitis group of viruses, and is closely related to louping ill virus (LIV). Naturally acquired disease in goats results in severe, acute encephalitis and 100% mortality. Eighteen goats were challenged subcutaneously with SGEV; nine were vaccinated previously against LIV and nine were not. None of the vaccinated goats showed any clinical signs of disease or histological lesions, but all of the non-vaccinated goats developed pyrexia and 5/9 developed neurological clinical signs, primarily tremors in the neck and ataxia. All non-vaccinated animals developed histological lesions restricted to the central nervous system and consistent with a lymphocytic meningomyeloencephalitis. Vaccinated goats had significantly (P goats throughout the experiment, but increased rapidly and were significantly (P goats against LIV confers highly effective protection against SGEV; this is probably mediated by IgG and prevents an increase in viral RNA load in serum such that vaccinated animals would not be an effective reservoir of the virus. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Experimental evidence that litter size imposes an oxidative challenge to offspring.

    Science.gov (United States)

    Gibson, Alyssa B; Garratt, Michael; Brooks, Robert C

    2015-12-01

    The post-natal environment in which young develop can substantially impact development, adult phenotype and fitness. In wild mice, competition among litter-mates affects development rate and adult behaviour. We manipulated post-natal litter size in a cross-fostering design to investigate the effects of enlarged and reduced litter sizes on sexual signalling, oxidative stress and the links between them. Oxidative stress causes somatic damage that can limit reproductive success and lifespan, and is predicted to mediate investment in life-history traits, including sexual signals. We predicted that litter enlargement would cause an increase in potential oxidative stress, inhibit growth and reduce sexual signalling in male mice. Males reared in enlarged litters were smaller at weaning and, despite rapid growth immediately after weaning, remained smaller at 10 weeks of age than those reared in smaller litters. Females from enlarged litters were consistently smaller throughout post-weaning development and showed no increase in growth rate compared with females from reduced litters. In enlarged litters, protein thiol concentration was lower at weaning in the liver and kidneys, with this trend continuing at 10 weeks of age in the kidneys only. Aconitase enzyme activity was also lower in mice from enlarged litters at weaning and 10 weeks of age in the kidneys. Male mice from enlarged litters scent marked more frequently and had larger preputial glands than those from reduced litters, indicating greater sexual signalling investment irrespective of this increased oxidative challenge. The results of this study are the first to reveal oxidative costs of developmental stress in small mammals. © 2015. Published by The Company of Biologists Ltd.

  7. Parasitemia in an immunocompetent horse experimentally challenged with Sarcocystis neurona sporocysts.

    Science.gov (United States)

    Rossano, M G; Schott, H C; Murphy, A J; Kaneene, J B; Sellon, D C; Hines, M T; Hochstatter, T; Bell, J A; Mansfield, L S

    2005-01-04

    Equine protozoal myeloencephalitis (EPM) is a serious neurological disease of horses in Americans. Most cases are attributed to infection of the central nervous system with Sarcocystis neurona. Parasitemia has not been demonstrated in immunocompetent horses, but has been documented in one immunocompromised foal. The objective of this study was to isolate viable S. neurona from the blood of immunocompetent horses. Horses used in this study received orally administered S. neurona sporocysts (strain SN 37-R) daily for 112 days at the following doses: 100/day for 28 days, followed by 500/day for 28 days, followed by 1000/day for 56 days. On day 98 of the study, six yearling colts were selected for attempted culture of S. neurona from blood, two testing positive, two testing suspect and two testing negative for antibodies against S. neurona on day 84 of the study. Two 10 ml tubes with EDTA were filled from each horse by jugular venipuncture and the plasma fraction rich in mononuclear cells was pipetted onto confluent equine dermal cell cultures. The cultures were monitored weekly for parasite growth for 12 weeks. Merozoites grown from cultures were harvested and tested using S. neurona-specific PCR with RFLP to confirm species identity. PCR products were sequenced and compared to known strains of S. neurona. After 38 days of in vitro incubation, one cell culture from a horse testing positive for antibodies against S. neurona was positive for parasite growth while the five remaining cultures remained negative for parasite growth for all 12 weeks. The Sarcocystis isolate recovered from cell culture was confirmed to be S. neurona by PCR with RFLP. Gene sequence analysis revealed that the isolate was identical to the challenge strain SN-37R and differed from two known strains UCD1 and MIH1. To our knowledge this is the first report of parasitemia with S. neurona in an immunocompetent horse.

  8. Experimental investigation of performance and emissions of a VCR diesel engine fuelled with n-butanol diesel blends under varying engine parameters.

    Science.gov (United States)

    Nayyar, Ashish; Sharma, Dilip; Soni, Shyam Lal; Mathur, Alok

    2017-09-01

    The continuous rise in the cost of fossil fuels as well as in environmental pollution has attracted research in the area of clean alternative fuels for improving the performance and emissions of internal combustion (IC) engines. In the present work, n-butanol is treated as a bio-fuel and investigations have been made to evaluate the feasibility of replacing diesel with a suitable n-butanol-diesel blend. In the current research, an experimental investigation was carried out on a variable compression ratio CI engine with n-butanol-diesel blends (10-25% by volume) to determine the optimum blending ratio and optimum operating parameters of the engine for reduced emissions. The best results of performance and emissions were observed for 20% n-butanol-diesel blend (B20) at a higher compression ratio as compared to diesel while keeping the other parameters unchanged. The observed deterioration in engine performance was within tolerable limits. The reductions in smoke, nitrogen oxides (NO x ), and carbon monoxide (CO) were observed up to 56.52, 17.19, and 30.43%, respectively, for B20 in comparison to diesel at rated power. However, carbon dioxide (CO 2 ) and hydrocarbons (HC) were found to be higher by 17.58 and 15.78%, respectively, for B20. It is concluded that n-butanol-diesel blend would be a potential fuel to control emissions from diesel engines. Graphical abstract ᅟ.

  9. Phase separation in coamorphous systems: in silico prediction and the experimental challenge of detection.

    Science.gov (United States)

    Pajula, Katja; Wittoek, Lieke; Lehto, Vesa-Pekka; Ketolainen, Jarkko; Korhonen, Ossi

    2014-07-07

    Combinatorial chemistry has enabled the production of very potent drugs that might otherwise suffer from poor solubility and low oral bioavailability. One approach to increase solubility is to make the drug amorphous, which leads to problems associated with drug stability. To improve stability, one option is to molecularly disperse the drug in a matrix. However, the primary reason for the failed stabilization with this approach is phase separation, which has been carefully studied in polymeric systems. Nevertheless, the amorphous-amorphous phase separation in coamorphous small molecule mixtures has not yet been reported. The goal of the present study was to experimentally detect the amorphous-amorphous phase separation between two small molecules. A modified in silico method for predicting miscibility by the Flory-Huggins interaction parameter is presented, where conformational variations of the studied molecules were taken into account. A series of drug-drug mixtures, with different mixture ratios, were analyzed by conventional differential scanning calorimetry (DSC(conv)) to detect possible amorphous-amorphous phase separations. The phase separation of coamorphous drug-drug mixtures was also monitored by temperature modulated DSC (MDSC) and Fourier transform infrared (FT-IR) imaging at temperatures above Tg for prolonged time periods. Amorphous-amorphous phase separation was not detected with DSC(conv), probably due to the slow kinetics of phase separation. However, the melting of the separated and subsequently crystallized phases was detected by MDSC. Furthermore, FT-IR imaging was able to detect the separation of the two amorphous phases, which demonstrates the ability of this method to detect small molecule phase separations.

  10. Expanding the three Rs to meet new challenges in humane animal experimentation.

    Science.gov (United States)

    Schuppli, Catherine A; Fraser, David; McDonald, Michael

    2004-11-01

    The Three Rs are the main principles used by Animal Ethics Committees in the governance of animal experimentation, but they appear not to cover some ethical issues that arise today. These include: a) claims that certain species should be exempted on principle from harmful research; b) increased emphasis on enhancing quality of life of research animals; c) research involving genetically modified (GM) animals; and d) animals bred as models of disease. In some cases, the Three Rs can be extended to cover these developments. The burgeoning use of GM animals in science calls for new forms of reduction through improved genetic modification technology, plus continued attention to alternative approaches and cost-benefit analyses that include the large numbers of animals involved indirectly. The adoption of more expanded definitions of refinement that go beyond minimising distress will capture concerns for enhancing the quality of life of animals through improved husbandry and handling. Targeting refinement to the unpredictable effects of gene modification may be difficult; in these cases, careful attention to monitoring and endpoints are the obvious options. Refinement can also include sharing data about the welfare impacts of gene modifications, and modelling earlier stages of disease, in order to reduce the potential suffering caused to disease models. Other issues may require a move beyond the Three Rs. Certain levels of harm, or numbers and use of certain species, may be unacceptable, regardless of potential benefits. This can be addressed by supplementing the utilitarian basis of the Three Rs with principles based on deontological and relational ethics. The Three Rs remain very useful, but they require thoughtful interpretation and expansion in order for Animal Ethics Committees to address the full range of issues in animal-based research.

  11. The Multilayered Challenges of Contemporary Graduate Training in Biochemistry and Experimental Biology

    Directory of Open Access Journals (Sweden)

    João Ramalho Santos

    2017-07-01

    Full Text Available Graduate training in Science at the Masters and Ph.D. levels has changed in recent years, especially involving increasing focus on soft skills and career diversification in a global world. Taking advantage of a fifteen-year experience in the distinct philosophies of the Masters is Biochemistry (MBq, Masters in Biology (MB, Masters in Molecular Cell Biology (MBCM, Ph.D. in Biosciences (PDBsc and Ph.D. in Experimental Biology and Biomedicine (PDBEB at the University of Coimbra, several of these aspects will be brought into focus via examples throughout the talk. Of course, a strong basis in key scientific skills, and the ability to adequately and creatively address all the modern technological and conceptual innovations in each field is still paramount, and should never be neglected as the most important aspect of graduate training. Exposing students to distinct sub-fields and speakers with distinct styles and experiences is also crucial to ensure breadth of training, but avoid formatting. In parallel, students should get solid exposure to complementary skills including aspects related to intellectual property, industry connections and entrepreneurship, bioethics, science policy/lobbying, or scientific writing, among many others. Notably, the importance of societal issues and science engagement activities with different kinds of audiences has increased, with attention being paid to proper science dissemination and communication strategies. It is crucial that students be made aware of ever changing options in terms of career development, for example via positive reinforcement using examples of program alumni with diverse experiences, and that, besides outstanding science, have gone on to other relevant activities. In parallel, the main pitfalls in proper career development should also be highlighted, so that students can make informed decisions. Perhaps the main issue is the recognition that one size does not fit all, and that there are several

  12. Experimental investigations on effect of different materials and varying depths of one turn exhaust channel swiss roll combustor on its thermal performance

    Science.gov (United States)

    Mane Deshmukh, Sagar B.; Krishnamoorthy, A.; Bhojwani, V. K.; Pawane, Ashwini

    2017-05-01

    More energy density of hydrocarbon fuels compared to advanced batteries available in the market demands for development of systems which will use hydrocarbon fuels at small scale to generate power in small quantity (i.e. in few watts) and device efficiency should be reasonably good, but the basic requirement is to generate heat from the fuels like methane, propane, hydrogen, LPG and converting into power. Swiss roll combustor has proved to be best combustor at small scale. Present work is carried out on one turn exhaust channel and half turn of inlet mixture channel Swiss roll combustor. Purpose of keeping exhaust channel length more than the inlet mixture channel to ensure sufficient time for heat exchange between burned and unburned gases, which is not reported in earlier studies. Experimental study mentions effects of different design parameters like materials of combustor, various depths, equivalence ratio, mass flow rates of liquefied petroleum gas (LPG), volume of combustion space and environmental conditions (with insulation and without insulation to combustors) on fuel lean limit and fuel rich limit, temperature profile obtained on all external surfaces, in the main combustion chamber, in the channel carrying unburned gas mixture and burned gas mixture, heat loss to atmosphere from all the walls of combustor, flame location. Different combustor materials tested were stainless steel, Aluminum, copper, brass, bronze, Granite. Depths considered were 22mm, 15mm, 10mm and 5mm. It was observed that flame stability inside the combustion chamber is affected by materials, depths and flow rates. Unburned mixture carrying channel was kept below quenching distance of flame to avoid flash back. Burned gas carrying channel dimension was more than the quenching distance. Considerable temperature rise was observed with insulation to combustors. But combustors with more thermal conductivity showed more heat loss to atmosphere which led to instability of flame.

  13. Eimeria maxima microneme protein 2 delivered as DNA vaccine and recombinant protein induces immunity against experimental homogenous challenge.

    Science.gov (United States)

    Huang, Jingwei; Zhang, Zhenchao; Li, Menghui; Song, Xiaokai; Yan, Ruofeng; Xu, Lixin; Li, Xiangrui

    2015-10-01

    E. maxima is one of the seven species of Eimeria that infects chicken. Until now, only a few antigenic genes of E. maxima have been reported. In the present study, the immune protective effects against E. maxima challenge of recombinant protein and DNA vaccine encoding EmMIC2 were evaluated. Two-week-old chickens were randomly divided into five groups. The experimental group of chickens was immunized with 100 μg DNA vaccine pVAX1-MIC2 or 200 μg rEmMIC2 protein while the control group of chickens was injected with pVAX1 plasmid or sterile PBS. The results showed that the anti-EmMIC2 antibody titers of both rEmMIC2 protein and pVAX1-MIC2 groups were significantly higher as compared to PBS and pVAX1 control (Pmaxima challenge and it could be an effective antigen candidate for the development of new vaccines against E. maxima. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. A Neospora caninum vaccine using recombinant proteins fails to prevent foetal infection in pregnant cattle after experimental intravenous challenge.

    Science.gov (United States)

    Hecker, Yanina P; Cóceres, Verónica; Wilkowsky, Silvina E; Jaramillo Ortiz, José M; Morrell, Eleonora L; Verna, Andrea E; Ganuza, Agustina; Cano, Dora B; Lischinsky, Lilian; Angel, Sergio O; Zamorano, Patricia; Odeón, Anselmo C; Leunda, María R; Campero, Carlos M; Morein, Bror; Moore, Dadín P

    2014-12-15

    The aim of the present study was to evaluate the immunogenicity and protective efficacy of rNcSAG1, rNcHSP20 and rNcGRA7 recombinant proteins formulated with immune stimulating complexes (ISCOMs) in pregnant heifers against vertical transmission of Neospora caninum. Twelve pregnant heifers were divided into 3 groups of 4 heifers each, receiving different formulations before mating. Immunogens were administered twice subcutaneously: group A animals were inoculated with three recombinant proteins (rNcSAG1, rNcHSP20, rNcGRA7) formulated with ISCOMs; group B animals received ISCOM-MATRIX (without antigen) and group C received sterile phosphate-buffered saline (PBS) only. The recombinant proteins were expressed in Escherichia coli and purified nickel resin. All groups were intravenously challenged with the NC-1 strain of N. caninum at Day 70 of gestation and dams slaughtered at week 17 of the experiment. Heifers from group A developed specific antibodies against rNcSAG1, rNcHSP20 and rNcGRA7 prior to the challenge. Following immunization, an statistically significant increase of antibodies against rNcSAG1 and rNcHSP20 in all animals of group A was detected compared to animals in groups B and C at weeks 5, 13 and 16 (P0.001). There were no differences in IFN-γ production among the experimental groups at any time point (P>0.05). Transplacental transmission was determined in all foetuses of groups A, B and C by Western blot, immunohistochemistry and nested PCR. This work showed that rNcSAG1, rNcHSP20 and rNcGRA7 proteins while immunogenic in cattle failed to prevent the foetal infection in pregnant cattle challenged at Day 70 of gestation. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Experimental effects of climate messages vary geographically

    Science.gov (United States)

    Zhang, Baobao; van der Linden, Sander; Mildenberger, Matto; Marlon, Jennifer R.; Howe, Peter D.; Leiserowitz, Anthony

    2018-05-01

    Social science scholars routinely evaluate the efficacy of diverse climate frames using local convenience or nationally representative samples1-5. For example, previous research has focused on communicating the scientific consensus on climate change, which has been identified as a `gateway' cognition to other key beliefs about the issue6-9. Importantly, although these efforts reveal average public responsiveness to particular climate frames, they do not describe variation in message effectiveness at the spatial and political scales relevant for climate policymaking. Here we use a small-area estimation method to map geographical variation in public responsiveness to information about the scientific consensus as part of a large-scale randomized national experiment (n = 6,301). Our survey experiment finds that, on average, public perception of the consensus increases by 16 percentage points after message exposure. However, substantial spatial variation exists across the United States at state and local scales. Crucially, responsiveness is highest in more conservative parts of the country, leading to national convergence in perceptions of the climate science consensus across diverse political geographies. These findings not only advance a geographical understanding of how the public engages with information about scientific agreement, but will also prove useful for policymakers, practitioners and scientists engaged in climate change mitigation and adaptation.

  16. An analytical and experimental approach for pressure distribution analysis of a particular lobe and plain bearing performance keeping in view of all impeding varying parameters associating with fixed lubrication SAE20W40

    International Nuclear Information System (INIS)

    Biswas, Nabarun; Chakraborti, Prasun; Belkar, Sanjay

    2016-01-01

    This paper presents both analytical and experimental pressure analysis approach of a typical Lobe and plain bearing for determining effective performance of the bearing. This is found to be dependent on several variables viz. angular velocity (1200-1900 rpm), load (300- 750 N) and pressure angle (0.deg.-180.deg.). This study in particular has been carried out for better rectifications and comparative prediction of lobe and plain bearing in terms of pressure distribution behavior under lubrication oil grade of SAE20W40. Influencing parameters were varied in this set up only to get optimum parametric combination considering all relevant practical issues. The experimentation was done based on significant directives of relevant literatures in these sectors. Attempt was made to compare the analytical findings with experimental results and found matched appreciably. After that attention was diverted to find the nature of pressure and load carrying capacity at various fluctuating speed and load with a fixed lubrication of SAE20W40 for appropriate decision making towards its characteristic performance. The analytical data generated by MATLAB are compared with experimental data which is generated by JBTR

  17. An analytical and experimental approach for pressure distribution analysis of a particular lobe and plain bearing performance keeping in view of all impeding varying parameters associating with fixed lubrication SAE20W40

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Nabarun; Chakraborti, Prasun [National Institute of Technology Agartala, Jirania (India); Belkar, Sanjay [Pravara Rural Engineering CollegeLoni, Rahata taluka (India)

    2016-05-15

    This paper presents both analytical and experimental pressure analysis approach of a typical Lobe and plain bearing for determining effective performance of the bearing. This is found to be dependent on several variables viz. angular velocity (1200-1900 rpm), load (300- 750 N) and pressure angle (0.deg.-180.deg.). This study in particular has been carried out for better rectifications and comparative prediction of lobe and plain bearing in terms of pressure distribution behavior under lubrication oil grade of SAE20W40. Influencing parameters were varied in this set up only to get optimum parametric combination considering all relevant practical issues. The experimentation was done based on significant directives of relevant literatures in these sectors. Attempt was made to compare the analytical findings with experimental results and found matched appreciably. After that attention was diverted to find the nature of pressure and load carrying capacity at various fluctuating speed and load with a fixed lubrication of SAE20W40 for appropriate decision making towards its characteristic performance. The analytical data generated by MATLAB are compared with experimental data which is generated by JBTR.

  18. Resistance to classical scrapie in experimentally challenged goats carrying mutation K222 of the prion protein gene

    Directory of Open Access Journals (Sweden)

    Acutis Pier Luigi

    2012-02-01

    Full Text Available Abstract Susceptibility of sheep to scrapie, a transmissible spongiform encephalopathy of small ruminants, is strongly influenced by polymorphisms of the prion protein gene (PRNP. Breeding programs have been implemented to increase scrapie resistance in sheep populations; though desirable, a similar approach has not yet been applied in goats. European studies have now suggested that several polymorphisms can modulate scrapie susceptibility in goats: in particular, PRNP variant K222 has been associated with resistance in case-control studies in Italy, France and Greece. In this study we investigated the resistance conferred by this variant using a natural Italian goat scrapie isolate to intracerebrally challenge five goats carrying genotype Q/Q 222 (wild type and five goats carrying genotype Q/K 222. By the end of the study, all five Q/Q 222 goats had died of scrapie after a mean incubation period of 19 months; one of the five Q/K 222 goats died after 24 months, while the other four were alive and apparently healthy up to the end of the study at 4.5 years post-challenge. All five of these animals were found to be scrapie negative. Statistical analysis showed that the probability of survival of the Q/K 222 goats versus the Q/Q 222 goats was significantly higher (p = 0.002. Our study shows that PRNP gene mutation K222 is strongly associated with resistance to classical scrapie also in experimental conditions, making it a potentially positive target for selection in the frame of breeding programs for resistance to classical scrapie in goats.

  19. Evaluation of the efficacy and duration of immunity of a canine combination vaccine against virulent parvovirus, infectious canine hepatitis virus, and distemper virus experimental challenges.

    Science.gov (United States)

    Abdelmagid, Omar Y; Larson, Laurie; Payne, Laurie; Tubbs, Anna; Wasmoen, Terri; Schultz, Ronald

    2004-01-01

    The results of this study confirmed that dogs vaccinated subcutaneously with a commercially available multivalent vaccine containing modified-live canine distemper virus, canine adenovirus type 2, canine parvovirus type 2b, and canine parainfluenza virus antigens were protected against sequential experimental challenge 55 to 57 months after initial vaccination given at 7 to 8 weeks of age. All 10 vaccinates were protected against clinical diseases and mortality following parvovirus and infectious canine hepatitis experimental infections. All vaccinates were protected against mortality and 90% against clinical disease following distemper challenge. These data support at least a 4-year duration of immunity for these three "core" fractions in the combination vaccine.

  20. The challenge of using experimental infectivity data in risk assessment for Ebola virus: why ecology may be important.

    Science.gov (United States)

    Gale, P; Simons, R R L; Horigan, V; Snary, E L; Fooks, A R; Drew, T W

    2016-01-01

    Analysis of published data shows that experimental passaging of Zaire ebolavirus (EBOV) in guinea pigs changes the risk of infection per plaque-forming unit (PFU), increasing infectivity to some species while decreasing infectivity to others. Thus, a PFU of monkey-adapted EBOV is 10(7) -fold more lethal to mice than a PFU adapted to guinea pigs. The first conclusion is that the infectivity of EBOV to humans may depend on the identity of the donor species itself and, on the basis of limited epidemiological data, the question is raised as to whether bat-adapted EBOV is less infectious to humans than nonhuman primate (NHP)-adapted EBOV. Wildlife species such as bats, duikers and NHPs are naturally infected by EBOV through different species giving rise to EBOV with different wildlife species-passage histories (heritages). Based on the ecology of these wildlife species, three broad 'types' of EBOV-infected bushmeat are postulated reflecting differences in the number of passages within a given species, and hence the degree of adaptation of the EBOV present. The second conclusion is that the prior species-transmission chain may affect the infectivity to humans per PFU for EBOV from individuals of the same species. This is supported by the finding that the related Marburg marburgvirus requires ten passages in mice to fully adapt. It is even possible that the evolutionary trajectory of EBOV could vary in individuals of the same species giving rise to variants which are more or less virulent to humans and that the probability of a given trajectory is related to the heritage. Overall the ecology of the donor species (e.g. dog or bushmeat species) at the level of the individual animal itself may determine the risk of infection per PFU to humans reflecting the heritage of the virus and may contribute to the sporadic nature of EBOV outbreaks. © 2015 Crown copyright. © 2015 Society for Applied Microbiology.

  1. Increased oxidative stress and severe arterial remodeling induced by permanent high-flow challenge in experimental pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Fadel Elie

    2011-09-01

    Full Text Available Abstract Background Involvement of inflammation in pulmonary hypertension (PH has previously been demonstrated and recently, immune-modulating dendritic cells (DCs infiltrating arterial lesions in patients suffering from idiopathic pulmonary arterial hypertension (IPAH and in experimental monocrotaline-induced PH have been reported. Occurrence of perivascular inflammatory cells could be linked to local increase of oxidative stress (OS, as it has been shown for systemic atherosclerosis. The impact of OS on vascular remodeling in PH is still to be determined. We hypothesized, that augmented blood-flow could increase OS and might thereby contribute to DC/inflammatory cell-recruitment and smooth-muscle-cell-proliferation. Methods We applied a monocrotaline-induced PH-model and combined it with permanent flow-challenge. Thirty Sprague-Dawley rats were assigned to following groups: control, monocrotaline-exposure (MCT, monocrotaline-exposure/pneumonectomy (MCT/PE. Results Hemodynamic exploration demonstrated most severe effects in MCT/PE, corresponding in histology to exuberant medial and adventitial remodeling of pulmonary muscular arteries, and intimal remodeling of smaller arterioles; lung-tissue PCR evidenced increased expression of DCs-specific fascin, CD68, proinflammatory cytokines (IL-6, RANTES, fractalkine in MCT/PE and to a lesser extent in MCT. Major OS enzyme NOX-4 was maximal in MCT/PE. Antioxidative stress enzymes Mn-SOD and glutathion-peroxidase-1 were significantly elevated, while HO-1 showed maximal expression in MCT with significant decrease in MCT/PE. Catalase was decreased in MCT and MCT/PE. Expression of NOX-4, but also of MN-SOD in MCT/PE was mainly attributed to a highly increased number of interstitial and perivascular CXCR4/SDF1 pathway-recruited mast-cells. Stress markers malonedialdehyde and nitrotyrosine were produced in endothelial cells, medial smooth muscle and perivascular leucocytes of hypertensive vasculature

  2. Cell therapy for heart failure: a comprehensive overview of experimental and clinical studies, current challenges, and future directions.

    Science.gov (United States)

    Sanganalmath, Santosh K; Bolli, Roberto

    2013-08-30

    Despite significant therapeutic advances, the prognosis of patients with heart failure (HF) remains poor, and current therapeutic approaches are palliative in the sense that they do not address the underlying problem of the loss of cardiac tissue. Stem cell-based therapies have the potential to fundamentally transform the treatment of HF by achieving what would have been unthinkable only a few years ago-myocardial regeneration. For the first time since cardiac transplantation, a therapy is being developed to eliminate the underlying cause of HF, not just to achieve damage control. Since the initial report of cell therapy (skeletal myoblasts) in HF in 1998, research has proceeded at lightning speed, and numerous preclinical and clinical studies have been performed that support the ability of various stem cell populations to improve cardiac function and reduce infarct size in both ischemic and nonischemic cardiomyopathy. Nevertheless, we are still at the dawn of this therapeutic revolution. Many important issues (eg, mechanism(s) of action of stem cells, long-term engraftment, optimal cell type(s), and dose, route, and frequency of cell administration) remain to be resolved, and no cell therapy has been conclusively shown to be effective. The purpose of this article is to critically review the large body of work performed with respect to the use of stem/progenitor cells in HF, both at the experimental and clinical levels, and to discuss current controversies, unresolved issues, challenges, and future directions. The review focuses specifically on chronic HF; other settings (eg, acute myocardial infarction, refractory angina) are not discussed.

  3. Immune responses and protection against experimental challenge after vaccination of bison with Brucella abortus strains RB51 or RB51 overexpressing superoxide dismutase and Glycosyltransferase genes

    Science.gov (United States)

    Vaccination is a tool that could be beneficial in managing the high prevalence of brucellosis in free-ranging bison in Yellowstone National Park. In this study, we characterized immunologic responses and protection against experimental challenge after vaccination of bison with Brucella abortus stra...

  4. varying elastic parameters distributions

    KAUST Repository

    Moussawi, Ali

    2014-12-01

    The experimental identication of mechanical properties is crucial in mechanics for understanding material behavior and for the development of numerical models. Classical identi cation procedures employ standard shaped specimens, assume that the mechanical elds in the object are homogeneous, and recover global properties. Thus, multiple tests are required for full characterization of a heterogeneous object, leading to a time consuming and costly process. The development of non-contact, full- eld measurement techniques from which complex kinematic elds can be recorded has opened the door to a new way of thinking. From the identi cation point of view, suitable methods can be used to process these complex kinematic elds in order to recover multiple spatially varying parameters through one test or a few tests. The requirement is the development of identi cation techniques that can process these complex experimental data. This thesis introduces a novel identi cation technique called the constitutive compatibility method. The key idea is to de ne stresses as compatible with the observed kinematic eld through the chosen class of constitutive equation, making possible the uncoupling of the identi cation of stress from the identi cation of the material parameters. This uncoupling leads to parametrized solutions in cases where 5 the solution is non-unique (due to unknown traction boundary conditions) as demonstrated on 2D numerical examples. First the theory is outlined and the method is demonstrated in 2D applications. Second, the method is implemented within a domain decomposition framework in order to reduce the cost for processing very large problems. Finally, it is extended to 3D numerical examples. Promising results are shown for 2D and 3D problems.

  5. A proposed reductionist solution to address the methodological challenges of inconsistent reflexology maps and poor experimental controls in reflexology research: a discussion paper.

    Science.gov (United States)

    Jones, Jenny; Thomson, Patricia; Lauder, William; Leslie, Stephen J

    2013-03-01

    Reflexology is a complex massage intervention, based on the concept that specific areas of the feet (reflex points) correspond to individual internal organs within the body. Reflexologists trained in the popular Ingham reflexology method claim that massage to these points, using massage techniques unique to reflexology, stimulates an increase in blood supply to the corresponding organ. Reflexology researchers face two key methodological challenges that need to be addressed if a specific treatment-related hemodynamic effect is to be scientifically demonstrated. The first is the problem of inconsistent reflexology foot maps; the second is the issue of poor experimental controls. This article proposes a potential experimental solution that we believe can address both methodological challenges and in doing so, allow any specific hemodynamic treatment effect unique to reflexology to experimentally reveal itself.

  6. Experimental induction of motile Aeromonas septicemia in channel catfish (Ictalurus punctatus by waterborne challenge with virulent Aeromonas hydrophila

    Directory of Open Access Journals (Sweden)

    Dunhua Zhang

    2016-05-01

    Full Text Available Motile Aeromonas septicemia (MAS, caused by virulent clonal isolates of Aeromonas hydrophila (vAh, is emerging as a major disease in catfish (Ictalurus punctatus aquaculture in the Southeastern United States. Predisposing conditions leading to vAh infection in catfish were however largely unknown. The objective of this study was to investigate factors that predispose catfish to vAh infection and establish a waterborne challenge model that mimics natural occurrence of MAS. Results of this study indicated that wounding on the fish body surface was one of the key factors that predisposed catfish to vAh infection via waterborne route. Relatively uniform wounds were created by clipping part of the fish adipose fin. Adipose fin clipped (Af-clipped fish behaved normally in terms of swimming and feeding and no mortality occurred in the control treatment (a mock challenge. When subjected to challenge in vAh-infected water, Af-clipped fish were highly susceptible, showing typical symptoms of MAS observed in the field. The mortality rate of Af-clipped fish was significantly associated with vAh concentration, challenge time and water temperature. About 90% mortality occurred within 48 h when Af-clipped fish were challenged for 1 h with vAh at the concentration of 2 × 107 colony forming units per mL of water (27 ± 1 °C. The waterborne challenge model was further tested using four field isolates including A. hydrophila and A. veronii. All vAh isolates caused about 90% mortality of Af-clipped fish and one isolate of Aeromonas veronii caused no mortality under the same challenge conditions. The waterborne challenge model described in this study would facilitate urgently-needed studies of MAS prevention (such as wound avoidance and healing and control (such as prophylactic vaccination; antibiotics treatment and probiotics screening. Keywords: Adipose fin, Channel catfish, Motile Aeromonas septicemia, Virulent Aeromonas hydrophila, Waterborne challenge

  7. Quasi-experimental study designs series-paper 10: synthesizing evidence for effects collected from quasi-experimental studies presents surmountable challenges.

    Science.gov (United States)

    Becker, Betsy Jane; Aloe, Ariel M; Duvendack, Maren; Stanley, T D; Valentine, Jeffrey C; Fretheim, Atle; Tugwell, Peter

    2017-09-01

    To outline issues of importance to analytic approaches to the synthesis of quasi-experiments (QEs) and to provide a statistical model for use in analysis. We drew on studies of statistics, epidemiology, and social-science methodology to outline methods for synthesis of QE studies. The design and conduct of QEs, effect sizes from QEs, and moderator variables for the analysis of those effect sizes were discussed. Biases, confounding, design complexities, and comparisons across designs offer serious challenges to syntheses of QEs. Key components of meta-analyses of QEs were identified, including the aspects of QE study design to be coded and analyzed. Of utmost importance are the design and statistical controls implemented in the QEs. Such controls and any potential sources of bias and confounding must be modeled in analyses, along with aspects of the interventions and populations studied. Because of such controls, effect sizes from QEs are more complex than those from randomized experiments. A statistical meta-regression model that incorporates important features of the QEs under review was presented. Meta-analyses of QEs provide particular challenges, but thorough coding of intervention characteristics and study methods, along with careful analysis, should allow for sound inferences. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Spacetime-varying couplings and Lorentz violation

    International Nuclear Information System (INIS)

    Kostelecky, V. Alan; Lehnert, Ralf; Perry, Malcolm J.

    2003-01-01

    Spacetime-varying coupling constants can be associated with violations of local Lorentz invariance and CPT symmetry. An analytical supergravity cosmology with a time-varying fine-structure constant provides an explicit example. Estimates are made for some experimental constraints

  9. Detection of dynamically varying interaural time differences

    DEFF Research Database (Denmark)

    Kohlrausch, Armin; Le Goff, Nicolas; Breebaart, Jeroen

    2010-01-01

    of fringes surrounding the probe is equal to the addition of the effects of the individual fringes. In this contribution, we present behavioral data for the same experimental condition, called dynamically varying ITD detection, but for a wider range of probe and fringe durations. Probe durations varied...

  10. Effect of whole yeast cell product supplementation (CitriStim®) on immune responses and cecal microflora species in pullet and layer chickens during an experimental coccidial challenge.

    Science.gov (United States)

    Markazi, Ashley D; Perez, Victor; Sifri, Mamduh; Shanmugasundaram, Revathi; Selvaraj, Ramesh K

    2017-07-01

    Three separate experiments were conducted to study the effects of whole yeast cell product supplementation in pullets and layer hens. Body weight gain, fecal and intestinal coccidial oocyst counts, cecal microflora species, cytokine mRNA amounts, and CD4+ and CD8+ T-cell populations in the cecal tonsils were analyzed following an experimental coccidial infection. In Experiment I, day-old Leghorn layer chicks were fed 3 experimental diets with 0, 0.1, or 0.2% whole yeast cell product (CitriStim®, ADM, Decatur, IL). At 21 d of age, birds were challenged with 1 × 105 live coccidial oocysts. Supplementation with whole yeast cell product decreased the fecal coccidial oocyst count at 7 (P = 0.05) and 8 (P product and challenged with 1 × 105 live coccidial oocysts on d 25 of whole yeast cell product feeding. Supplementation with whole yeast cell product decreased the coccidial oocyst count in the intestinal content (P product increased relative proportion of Lactobacillus (P product decreased CD8+ T cell percentages (P product and challenged with 1 × 105 live coccidial oocysts on d 66 of whole yeast cell product feeding. At 5 d post-coccidial challenge, whole yeast cell product supplementation down-regulated (P = 0.01) IL-10 mRNA amount. It could be concluded that supplementing whole yeast cell product can help minimize coccidial infection in both growing pullets and layer chickens. © 2017 Poultry Science Association Inc.

  11. Submicron beam X-ray diffraction of nanoheteroepitaxily grown GaN: Experimental challenges and calibration procedures

    Energy Technology Data Exchange (ETDEWEB)

    Bonanno, P.L., E-mail: PeterBonanno@gatech.ed [Georgia Institute of Technology/GTL, UMI 2958 Georgia Tech-CNRS, 57070 Metz (France); Gautier, S. [Laboratoire Materiaux Optiques, Photonique et Micro-Nano Systemes, UMR CNRS 7132, Universite de Metz et SUPELEC, 2 rue E. Belin, 57070 Metz (France); Sirenko, A.A. [Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Kazimirov, A. [Cornell High Energy Synchrotron Source (CHESS), Cornell University, Ithaca, New York 14853 (United States); Cai, Z.-H. [Advanced Photon Source, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Goh, W.H. [Georgia Institute of Technology/GTL, UMI 2958 Georgia Tech-CNRS, 57070 Metz (France); Martin, J. [Laboratoire Materiaux Optiques, Photonique et Micro-Nano Systemes, UMR CNRS 7132, Universite de Metz et SUPELEC, 2 rue E. Belin, 57070 Metz (France); Martinez, A. [Laboratoire de Photonique et de Nanostructures, UPR CNRS 20, Route de Nozay, 91460 Marcoussis (France); Moudakir, T. [Laboratoire Materiaux Optiques, Photonique et Micro-Nano Systemes, UMR CNRS 7132, Universite de Metz et SUPELEC, 2 rue E. Belin, 57070 Metz (France); Maloufi, N. [Laboratoire d' Etude des Textures et Application aux Materiaux, UMR CNRS 7078, Ile du Saulcy, 57045 Metz Cedex 1 (France); Assouar, M.B. [Laboratoire de Physique des Milieux Ionises et Applications, Nancy University, CNRS, BP 239, F-54506 Vandoeuvre-les-Nancy Cedex (France); Ramdane, A.; Gratiet, L. Le [Laboratoire de Photonique et de Nanostructures, UPR CNRS 20, Route de Nozay, 91460 Marcoussis (France); Ougazzaden, A. [Georgia Institute of Technology/GTL, UMI 2958 Georgia Tech-CNRS, 57070 Metz (France)

    2010-02-15

    Highly relaxed GaN nanodots and submicron ridges have been selectively grown in the NSAG regime using MOVPE on lattice mismatched 6H-SiC and AlN substrates. 2D real space and 3D reciprocal space mapping was performed with a CCD detector using 10.4 keV synchrotron X-ray radiation at the 2-ID-D micro-diffraction beamline at Advanced Photon Source (APS). Calibration procedures have been developed to overcome the unique challenges of analyzing NSAG structures grown on highly mismatched substrates. We studied crystallographic planar bending on the submicron scale and found its correlation with strain relaxation in the NSAG ridges.

  12. Ultraviolet and soft X-ray free-electron lasers introduction to physical principles, experimental results, technological challenges

    CERN Document Server

    Schmüser, Peter; Rossbach, Jörg; Fujimori, A; Kühn, J; Müller, T; Steiner, F; Trümper, J; Varma, C; Wölfle, P

    2008-01-01

    In the introduction accelerator-based light sources are considered and a comparison is made between free-electron lasers and conventional quantum lasers. The motion and radiation of relativistic electrons in undulator magnets is discussed. The principle of a low-gain free-electron laser is explained and the pendulum equations are introduced that characterize the electron dynamics in the field of a light wave. The differential equations of the high-gain FEL are derived from the Maxwell equations of electrodynamics. Analytical and numerical solutions of the FEL equations are presented and important FEL parameters are defined, such as gain length, FEL bandwidth and saturation power. A detailed numerical study of the all-important microbunching process is presented. The mechanism of Self Amplified Spontaneous Emission is described theoretically and illustrated with numerous experimental results. Three-dimensional effects such as betatron oscillations and optical diffraction are addressed and their impact on the F...

  13. Time-varying BRDFs.

    Science.gov (United States)

    Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

    2007-01-01

    The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials.

  14. Implementation challenges for designing integrated in vitro testing strategies (ITS) aiming at reducing and replacing animal experimentation.

    Science.gov (United States)

    De Wever, Bart; Fuchs, Horst W; Gaca, Marianna; Krul, Cyrille; Mikulowski, Stan; Poth, Albrecht; Roggen, Erwin L; Vilà, Maya R

    2012-04-01

    At the IVTIP (in vitro testing industrial platform) meeting of November 26th 2009 entitled 'Toxicology in the 21st century ('21C')--working our way towards a visionary reality' all delegates endorsed the emerging concept of the '21C' vision as the way forward to enable a thorough, reliable and systematic approach to future toxicity testing without the use of animals. One of the emerging concepts focused on integrating a defined number of tests modelling in vivo-relevant and well-characterised toxicity pathways representing mechanistic endpoints. At this meeting the importance of Integrated Testing Strategies (ITS) as tools towards reduction and eventually replacement of the animals currently used for hazard identification and risk assessment was recognised. A follow-up IVTIP Spring 2010 meeting entitled 'Integrated In Vitro Testing Strategies (ITS)--Implementation Challenges' was organised to address pending questions about ITS. This report is not a review of the ITS literature, but a summary of the discussions triggered by presented examples on how to develop and implement ITS. Contrasts between pharmaceutical and chemical industry, as well as a list of general but practical aspects to be considered while developing an ITS emerged from the discussions. In addition, current recommendations on the validation of ITS were discussed. In conclusion, the outcome of this workshop improved the understanding of the participants of some important factors that may impact the design of an ITS in function of its purpose (e.g., screening, or early decision making versus regulatory), the context in which they need to be applied (e.g., ICH guidelines, REACH) and the status and quality of the available tools. A set of recommendations of best practices was established and the importance of the applicability of the individual tests as well as the testing strategy itself was highlighted. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Passive immunization with a polyclonal antiserum to the hemoglobin receptor of Haemophilus ducreyi confers protection against a homologous challenge in the experimental swine model of chancroid.

    Science.gov (United States)

    Leduc, Isabelle; Fusco, William G; Choudhary, Neelima; Routh, Patty A; Cholon, Deborah M; Hobbs, Marcia M; Almond, Glen W; Orndorff, Paul E; Elkins, Christopher

    2011-08-01

    Haemophilus ducreyi, the etiologic agent of chancroid, has an obligate requirement for heme. Heme is acquired by H. ducreyi from its human host via TonB-dependent transporters expressed at its bacterial surface. Of 3 TonB-dependent transporters encoded in the genome of H. ducreyi, only the hemoglobin receptor, HgbA, is required to establish infection during the early stages of the experimental human model of chancroid. Active immunization with a native preparation of HgbA (nHgbA) confers complete protection in the experimental swine model of chancroid, using either Freund's or monophosphoryl lipid A as adjuvants. To determine if transfer of anti-nHgbA serum is sufficient to confer protection, a passive immunization experiment using pooled nHgbA antiserum was conducted in the experimental swine model of chancroid. Pigs receiving this pooled nHgbA antiserum were protected from a homologous, but not a heterologous, challenge. Passively transferred polyclonal antibodies elicited to nHgbA bound the surface of H. ducreyi and partially blocked hemoglobin binding by nHgbA, but were not bactericidal. Taken together, these data suggest that the humoral immune response to the HgbA vaccine is protective against an H. ducreyi infection, possibly by preventing acquisition of the essential nutrient heme.

  16. Passive Immunization with a Polyclonal Antiserum to the Hemoglobin Receptor of Haemophilus ducreyi Confers Protection against a Homologous Challenge in the Experimental Swine Model of Chancroid▿

    Science.gov (United States)

    Leduc, Isabelle; Fusco, William G.; Choudhary, Neelima; Routh, Patty A.; Cholon, Deborah M.; Hobbs, Marcia M.; Almond, Glen W.; Orndorff, Paul E.; Elkins, Christopher

    2011-01-01

    Haemophilus ducreyi, the etiologic agent of chancroid, has an obligate requirement for heme. Heme is acquired by H. ducreyi from its human host via TonB-dependent transporters expressed at its bacterial surface. Of 3 TonB-dependent transporters encoded in the genome of H. ducreyi, only the hemoglobin receptor, HgbA, is required to establish infection during the early stages of the experimental human model of chancroid. Active immunization with a native preparation of HgbA (nHgbA) confers complete protection in the experimental swine model of chancroid, using either Freund's or monophosphoryl lipid A as adjuvants. To determine if transfer of anti-nHgbA serum is sufficient to confer protection, a passive immunization experiment using pooled nHgbA antiserum was conducted in the experimental swine model of chancroid. Pigs receiving this pooled nHgbA antiserum were protected from a homologous, but not a heterologous, challenge. Passively transferred polyclonal antibodies elicited to nHgbA bound the surface of H. ducreyi and partially blocked hemoglobin binding by nHgbA, but were not bactericidal. Taken together, these data suggest that the humoral immune response to the HgbA vaccine is protective against an H. ducreyi infection, possibly by preventing acquisition of the essential nutrient heme. PMID:21646451

  17. Experimental challenge and pathology of highly pathogenic avian influenza virus H5N1 in dunlin (Calidris alpina), an intercontinental migrant shorebird species

    Science.gov (United States)

    Hall, Jeffrey S.; Franson, J. Christian; Gill, Robert E.; Meteyer, Carol U.; TeSlaa, Joshua L.; Nashold, Sean W.; Dusek, Robert J.; Ip, Hon S.

    2011-01-01

    Background Shorebirds (Charadriiformes) are considered one of the primary reservoirs of avian influenza. Because these species are highly migratory, there is concern that infected shorebirds may be a mechanism by which highly pathogenic avian influenza virus (HPAIV) H5N1 could be introduced into North America from Asia. Large numbers of dunlin (Calidris alpina) migrate from wintering areas in central and eastern Asia, where HPAIV H5N1 is endemic, across the Bering Sea to breeding areas in Alaska. Low pathogenic avian influenza virus has been previously detected in dunlin, and thus, dunlin represent a potential risk to transport HPAIV to North America. To date no experimental challenge studies have been performed in shorebirds.

  18. Scoping-level Probabilistic Safety Assessment of a complex experimental facility: Challenges and first results from the application to a neutron source facility (MEGAPIE)

    International Nuclear Information System (INIS)

    Podofillini, L.; Dang, V.N.; Thomsen, K.

    2008-01-01

    This paper presents a scoping-level application of Probabilistic Safety Assessment (PSA) to selected systems of a complex experimental facility. In performing a PSA for this type of facility, a number of challenges arise, mainly due to the extensive use of electronic and programmable components and of one-of-a-kind components. The experimental facility is the Megawatt Pilot Target Experiment (MEGAPIE), which was hosted at the Paul Scherrer Institut (PSI). MEGAPIE demonstrated the feasibility of a liquid lead-bismuth target for spallation facilities at a proton beam power level of 1 MW. Given the challenges to estimate initiating event frequencies and failure event probabilities, emphasis is placed on the qualitative results obtainable from the PSA. Even though this does not allow a complete and appropriate characterization of the risk profile, some level of importance/significance evaluation was feasible, and practical and detailed recommendations on potential system improvements were derived. The second part of the work reports on a preliminary quantification of the facility risk. This provides more information on risk significance, which allows prioritizing the insights and recommendations obtained from the PSA. At the present stage, the limited knowledge on initiating and failure events is reflected in the uncertainties in their probabilities as well as in inputs quantified with bounding values. Detailed analyses to improve the quantification of these inputs, many of which turn out to be important contributors, were out of the scope of this study. Consequently, the reported results should be primarily considered as a demonstration of how quantification of the facility risk by a PSA can support risk-informed decisions, rather than precise figures of the facility risk

  19. Varying Constants, Gravitation and Cosmology

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Uzan

    2011-03-01

    Full Text Available Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  20. Experimental Challenges and Successes in Measuring Aerosol Concentrations at Prototypic Spray Conditions Encountered at the Hanford Waste Treatment and Immobilization Plant - 13327

    Energy Technology Data Exchange (ETDEWEB)

    Bontha, J.R.; Gauglitz, P.A.; Kurath, D.E.; Adkins, H.E.; Enderlin, C.W.; Blanchard, J.; Daniel, R.C.; Song, C.; Schonewill, P.P.; Mahoney, L.A.; Buchmiller, W.C.; Boeringa, G.; Jenks, J. [Pacific Northwest National Laboratory, PO Box 999, Richland, Washington 99352 (United States)

    2013-07-01

    To date, majority of the work done on measuring aerosol releases from failure of process piping was done using simple Newtonian fluids and small engineered-nozzles that do not accurately represent the fluids and breaches postulated during accident analysis at the Hanford Waste Treatment and Immobilization Plant (WTP). In addition, the majority of the work conducted in this area relies on in-spray measurements that neglect the effect of splatter and do not yield any information regarding aerosol generation rates from this additional mechanism. In order to estimate aerosol generation rates as well as reduce the uncertainties in estimating the aerosol release fractions over a broad range of breaches, fluid properties and operating conditions encountered at the WTP, the Pacific Northwest National Laboratory (PNNL) has designed, commissioned, and tested two experimental test stands. The first test stand, referred to as the large-scale test stand, was designed specifically to measure aerosol concentrations and release fractions under prototypic conditions of flow and pressure for a range of breaches postulated in the hazard analysis for 0.076 m (3-inch) process pipes. However, the size of the large-scale test stand, anticipated fluid loss during a breach, experimental risks, and costs associated with hazardous chemical simulant testing limited the large-scale test stand utility to water and a few non-hazardous physical simulants that did not fully span the particle size and rheological properties of the fluids encountered at the WTP. Overcoming these limitations and extending the range of simulants used, required designing and building a smaller test stand, which was installed and operated in a fume hood. This paper presents some of the features of both test stands, the experimental challenges encountered, and successes in measuring aerosol concentration in both test stands over a range of test conditions. (authors)

  1. The challenge of modelling nitrogen management at the field scale: simulation and sensitivity analysis of N2O fluxes across nine experimental sites using DailyDayCent

    International Nuclear Information System (INIS)

    Fitton, N; Datta, A; Hastings, A; Kuhnert, M; Smith, P; Topp, C F E; Cloy, J M; Rees, R M; Cardenas, L M; Williams, J R; Smith, K; Chadwick, D

    2014-01-01

    The United Kingdom currently reports nitrous oxide emissions from agriculture using the IPCC default Tier 1 methodology. However Tier 1 estimates have a large degree of uncertainty as they do not account for spatial variations in emissions. Therefore biogeochemical models such as DailyDayCent (DDC) are increasingly being used to provide a spatially disaggregated assessment of annual emissions. Prior to use, an assessment of the ability of the model to predict annual emissions should be undertaken, coupled with an analysis of how model inputs influence model outputs, and whether the modelled estimates are more robust that those derived from the Tier 1 methodology. The aims of the study were (a) to evaluate if the DailyDayCent model can accurately estimate annual N 2 O emissions across nine different experimental sites, (b) to examine its sensitivity to different soil and climate inputs across a number of experimental sites and (c) to examine the influence of uncertainty in the measured inputs on modelled N 2 O emissions. DailyDayCent performed well across the range of cropland and grassland sites, particularly for fertilized fields indicating that it is robust for UK conditions. The sensitivity of the model varied across the sites and also between fertilizer/manure treatments. Overall our results showed that there was a stronger correlation between the sensitivity of N 2 O emissions to changes in soil pH and clay content than the remaining input parameters used in this study. The lower the initial site values for soil pH and clay content, the more sensitive DDC was to changes from their initial value. When we compared modelled estimates with Tier 1 estimates for each site, we found that DailyDayCent provided a more accurate representation of the rate of annual emissions. (paper)

  2. Functional feeds reduce heart inflammation and pathology in Atlantic Salmon (Salmo salar L. following experimental challenge with Atlantic salmon reovirus (ASRV.

    Directory of Open Access Journals (Sweden)

    Laura Martinez-Rubio

    Full Text Available Heart and Skeletal Muscle Inflammation (HSMI, recently associated with a novel Atlantic salmon reovirus (ASRV, is currently one of the most prevalent inflammatory diseases in commercial Atlantic salmon farms in Norway. Mortality varies from low to 20%, but morbidity can be very high, reducing growth performance and causing considerable financial impact. Clinical symptoms, including myocarditis, myocardial and red skeletal muscle necrosis, correlate with the intensity of the inflammatory response. In the present study, the effects of two functional feeds (FF1 and FF2 were compared to a standard commercial reference feed (ST in Atlantic salmon subjected to an ASRV challenge. The functional feeds had reduced levels of total lipid and digestible energy, and different levels and proportions of long-chain polyunsaturated fatty acids (LC-PUFA. The objective was to determine whether these feeds could provide effective protection by decreasing the inflammatory response associated with HSMI. Histopathology, viral load, fatty acid composition and gene expression of heart tissue were assessed over a period of 16 weeks post-infection with ASRV. The viral load and histopathology scores in heart tissue in response to ASRV infection were reduced in fish fed both functional feeds, with FF1 showing the greatest effect. Microarray hierarchical cluster analysis showed that the functional feeds greatly affected expression of inflammation/immune related genes over the course of the ASRV infection. Viral load correlated with up-regulation of pro-inflammatory genes at the early-mid stages of infection in fish fed the ST diet. Expression of inflammatory genes 16-weeks after ASRV challenge reflected the difference in efficacy between the functional feeds, with fish fed FF1 showing lower expression. Thus, severity of the lesions in heart tissue correlated with the intensity of the innate immune response and was associated with tissue fatty acid compositions. The present

  3. Experimental Challenge of a Peridomestic Avian Species, European Starlings ( Sturnus vulgaris ), with Novel Influenza A H7N9 Virus from China.

    Science.gov (United States)

    Hall, Jeffrey S; Ip, Hon S; TeSlaa, Joshua L; Nashold, Sean W; Dusek, Robert J

    2016-07-01

    In 2013 a novel avian influenza H7N9 virus was isolated from several critically ill patients in China, and infection with this virus has since caused more than 200 human deaths. Live poultry markets are the likely locations of virus exposure to humans. Peridomestic avian species also may play important roles in the transmission and maintenance of H7N9 at live poultry markets. We experimentally challenged wild European Starlings ( Sturnus vulgaris ) with the novel H7N9 virus and measured virus excretion, clinical signs, and infectious dose. We found that European Starlings can be infected with this virus when inoculated with relatively high doses, and we predict that infected birds excrete sufficient amounts of virus to transmit to other birds, including domestic chickens. Infected European Starlings showed no clinical signs or mortality after infection with H7N9. This abundant peridomestic bird may be a source of the novel H7N9 virus in live poultry markets and may have roles in virus transmission to poultry and humans.

  4. Experimental challenge of a peridomestic avian species, European Starlings (Sturnus vulgaris), with novel Influenza A H7N9 virus from China

    Science.gov (United States)

    Hall, Jeffrey S.; Ip, Hon S.; Teslaa, Joshua L.; Nashold, Sean W.; Dusek, Robert

    2016-01-01

    In 2013 a novel avian influenza H7N9 virus was isolated from several critically ill patients in China, and infection with this virus has since caused more than 200 human deaths. Live poultry markets are the likely locations of virus exposure to humans. Peridomestic avian species also may play important roles in the transmission and maintenance of H7N9 at live poultry markets. We experimentally challenged wild European Starlings (Sturnus vulgaris) with the novel H7N9 virus and measured virus excretion, clinical signs, and infectious dose. We found that European Starlings can be infected with this virus when inoculated with relatively high doses, and we predict that infected birds excrete sufficient amounts of virus to transmit to other birds, including domestic chickens. Infected European Starlings showed no clinical signs or mortality after infection with H7N9. This abundant peridomestic bird may be a source of the novel H7N9 virus in live poultry markets and may have roles in virus transmission to poultry and humans.

  5. An experimental and numerical analysis of the HCCI auto-ignition process of primary reference fuels, toluene reference fuels and diesel fuel in an engine, varying the engine parameters

    Energy Technology Data Exchange (ETDEWEB)

    Machrafi, Hatim; Cavadias, Simeon [UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris, 11, rue de Pierre et Marie Curie, 75005 Paris (France); UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert, 2, place de la Gare de Ceinture, 78210 St Cyr-I' Ecole (France); Gilbert, Philippe [UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert, 2, place de la Gare de Ceinture, 78210 St Cyr-I' Ecole (France)

    2008-11-15

    For a future HCCI engine to operate under conditions that adhere to environmental restrictions, reducing fuel consumption and maintaining or increasing at the same time the engine efficiency, the choice of the fuel is crucial. For this purpose, this paper presents an auto-ignition investigation concerning the primary reference fuels, toluene reference fuels and diesel fuel, in order to study the effect of linear alkanes, branched alkanes and aromatics on the auto-ignition. The auto-ignition of these fuels has been studied at inlet temperatures from 25 to 120 C, at equivalence ratios from 0.18 to 0.53 and at compression ratios from 6 to 13.5, in order to extend the range of investigation and to assess the usability of these parameters to control the auto-ignition. It appeared that both iso-octane and toluene delayed the ignition with respect to n-heptane, while toluene has the strongest effect. This means that aromatics have higher inhibiting effects than branched alkanes. In an increasing order, the inlet temperature, equivalence ratio and compression ratio had a promoting effect on the ignition delays. A previously experimentally validated reduced surrogate mechanism, for mixtures of n-heptane, iso-octane and toluene, has been used to explain observations of the auto-ignition process. (author)

  6. Inferring time-varying network topologies from gene expression data.

    Science.gov (United States)

    Rao, Arvind; Hero, Alfred O; States, David J; Engel, James Douglas

    2007-01-01

    Most current methods for gene regulatory network identification lead to the inference of steady-state networks, that is, networks prevalent over all times, a hypothesis which has been challenged. There has been a need to infer and represent networks in a dynamic, that is, time-varying fashion, in order to account for different cellular states affecting the interactions amongst genes. In this work, we present an approach, regime-SSM, to understand gene regulatory networks within such a dynamic setting. The approach uses a clustering method based on these underlying dynamics, followed by system identification using a state-space model for each learnt cluster--to infer a network adjacency matrix. We finally indicate our results on the mouse embryonic kidney dataset as well as the T-cell activation-based expression dataset and demonstrate conformity with reported experimental evidence.

  7. EXPERIMENTAL CHALLENGE STUDY OF FV3-LIKE RANAVIRUS INFECTION IN PREVIOUSLY FV3-LIKE RANAVIRUS INFECTED EASTERN BOX TURTLES (TERRAPENE CAROLINA CAROLINA) TO ASSESS INFECTION AND SURVIVAL.

    Science.gov (United States)

    Hausmann, Jennifer C; Wack, Allison N; Allender, Matthew C; Cranfield, Mike R; Murphy, Kevin J; Barrett, Kevin; Romero, Jennell L; Wellehan, James F X; Blum, Stella A; Zink, M Christine; Bronson, Ellen

    2015-12-01

    The Maryland Zoo in Baltimore experienced an outbreak of Frog virus-3 (FV3)-like ranavirus during the summer of 2011, during which 14 of 27 (52%) of its captive eastern box turtles (Terrapene carolina carolina) survived. To assess survival, immunity, and viral shedding, an experimental challenge study was performed in which the surviving, previously infected turtles were reinfected with the outbreak strain of FV3-like ranavirus. Seven turtles were inoculated with virus intramuscularly and four control turtles received saline intramuscularly. The turtles were monitored for 8 wk with blood and oral swabs collected for quantitative polymerase chain reaction (qPCR). During that time, one of seven (14%) inoculated turtles and none of the controls (0%) died; there was no significant difference in survival. Clinical signs of the inoculated turtles, except for the turtle that died, were mild compared to the original outbreak. Quantitative PCR for FV3-like ranavirus on blood and oral swabs was positive for all inoculated turtles and negative for all controls. The turtle that died had intracytoplasmic inclusion bodies in multiple organs. Three inoculated and two control turtles were euthanized at the end of the study. No inclusion bodies were present in any of the organs. Quantitative PCR detected FV3-like ranavirus in the spleen of a control turtle, which suggested persistence of the virus. The surviving five turtles were qPCR-negative for FV3-like ranavirus from blood and oral swabs after brumation. Quantitative PCR for Terrapene herpesvirus 1 found no association between ranavirus infection and herpesvirus loads. In conclusion, previously infected eastern box turtles can be reinfected with the same strain of FV3-like ranavirus and show mild to no clinical signs but can shed the virus from the oral cavity.

  8. Experimental challenge and pathology of highly pathogenic avian influenza virus H5N1 in dunlin (Calidris alpina), an intercontinental migrant shorebird species.

    Science.gov (United States)

    Hall, Jeffrey S; Franson, J Christian; Gill, Robert E; Meteyer, Carol U; TeSlaa, Joshua L; Nashold, Sean; Dusek, Robert J; Ip, Hon S

    2011-09-01

    Shorebirds (Charadriiformes) are considered one of the primary reservoirs of avian influenza. Because these species are highly migratory, there is concern that infected shorebirds may be a mechanism by which highly pathogenic avian influenza virus (HPAIV) H5N1 could be introduced into North America from Asia. Large numbers of dunlin (Calidris alpina) migrate from wintering areas in central and eastern Asia, where HPAIV H5N1 is endemic, across the Bering Sea to breeding areas in Alaska. Low pathogenic avian influenza virus has been previously detected in dunlin, and thus, dunlin represent a potential risk to transport HPAIV to North America. To date no experimental challenge studies have been performed in shorebirds. Wild dunlin were inoculated intranasally and intrachoanally various doses of HPAIV H5N1. The birds were monitored daily for virus excretion, disease signs, morbidity, and mortality. The infectious dose of HPAIV H5N1 in dunlin was determined to be 10(1.7) EID(50)/100 μl and that the lethal dose was 10(1.83) EID(50)/100 μl. Clinical signs were consistent with neurotropic disease, and histochemical analyses revealed that infection was systemic with viral antigen and RNA most consistently found in brain tissues. Infected birds excreted relatively large amounts of virus orally (10(4) EID(50)) and smaller amounts cloacally. Dunlin are highly susceptible to infection with HPAIV H5N1. They become infected after exposure to relatively small doses of the virus and if they become infected, they are most likely to suffer mortality within 3-5 days. These results have important implications regarding the risks of transport and transmission of HPAIV H5N1 to North America by this species and raises questions for further investigation. Published 2011. This article is a US Government work and is in the public domain in the USA.

  9. Evolução de variáveis hemodinâmicas e perfusionais durante o choque séptico experimental tratado com ressuscitação volêmica guiada por metas Hemodynamic and perfusion variables during experimental septic shock treated with goal-directed fluid resuscitation

    Directory of Open Access Journals (Sweden)

    Marcelo Park

    2011-09-01

    Full Text Available OBJETIVOS: Apesar da ressuscitação volêmica guiada por saturação venosa central de oxigênio (SvcO2 ser considerada atualmente padrão ouro no tratamento da sepse, poucos estudos caracterizaram o perfil evolutivo de variáveis hemodinâmicas e perfusionais durante esta abordagem terapêutica. Este estudo teve por objetivo descrever evolutivamente estes parâmetros durante o choque séptico experimental sem ressuscitação e após 12 horas de ressuscitação guiada por metas. MÉTODOS: Treze porcos (35-45 kg anestesiados foram submetidos a peritonite por inoculação fecal (0,75g/kg. Após desenvolverem hipotensão persistente, ambos os grupos receberam antibióticos e foram randomizados em dois grupos: controle (n=7, com suporte hemodinâmico otimizado para pressão venosa central entre 8-12mmHg, diurese acima de 0,5ml/kg/h e pressão arterial média maior que 65mmHg; e SvO2 (n=6, com os objetivos acima e SvO2 acima de 65%. As intervenções incluíram ringer lactato e noradrenalina nos 2 grupos e dobutamina no grupo SvO2. Os animais foram tratados durante doze horas ou óbito. RESULTADOS: A sepse não tratada associou-se a uma significante redução da SvO2, PvO2, débito cardíaco e pressão venosa central e aumento da diferença arterio-venosa da saturação de oxigênio e veno-arterial de CO2. Após ressuscitação, esses parâmetros foram corrigidos em ambos os grupos. A ressuscitação guiada por metas associou-se a um melhor perfil hemodinâmico caracterizado por maiores SvO2, débito cardíaco e pressão venosa central. CONCLUSÕES: A sepse não ressuscitada apresenta um perfil hemodinâmico sugestivo de hipovolemia, com piora perfusional e hemodinâmica revertida após ressuscitação volêmica. A ressuscitação guiada por metas associa-se a uma significante melhora dos parâmetros hemodinâmicos e perfusionaisOBJECTIVES: Although fluid resuscitation guided by central venous oxygen saturation (SvcO2 is currently considered the

  10. Mate Preference of Female Blue Tits Varies with Experimental Photoperiod

    NARCIS (Netherlands)

    Reparaz, L.B.; Van Oers, K.; Naguib, M.; Doutrelant, C.; Visser, M.E.; Caro, S.P.

    2014-01-01

    Organisms use environmental cues to time their life-cycles and among these cues, photoperiod is the main trigger of reproductive behaviours such as territory defence or song activity. Whether photoperiod is also important for another behaviour closely associated with reproduction, mate choice, is

  11. Mate preference of female blue tits varies with experimental photoperiod

    NARCIS (Netherlands)

    Reparaz, L.B.; Oers, van K.; Naguib, M.; Doutrelant, C.; Visser, M.E.; Caro, S.P.

    2014-01-01

    Organisms use environmental cues to time their life-cycles and among these cues, photoperiod is the main trigger of reproductive behaviours such as territory defence or song activity. Whether photoperiod is also important for another behaviour closely associated with reproduction, mate choice, is

  12. The role of the dopaminergic system in mood, motivation and cognition in Parkinson's disease: a double blind randomized placebo-controlled experimental challenge with pramipexole and methylphenidate.

    Science.gov (United States)

    Drijgers, Rosa L; Verhey, Frans R J; Tissingh, Gerrit; van Domburg, Peter H M F; Aalten, Pauline; Leentjens, Albert F G

    2012-09-15

    In Parkinson's disease (PD) reduced dopaminergic activity in the mesocorticolimbic pathway is implied in the pathophysiology of several non-motor symptoms related to mood, motivation and cognition. Insight in the pathophysiology of these syndromes may pave the way for more rational treatments. In a double-blind, randomized, placebo controlled, crossover design with three arms, we studied the effects of a direct dopaminergic challenge with the dopamine 2 receptor agonist pramipexole, an indirect challenge with the dopamine reuptake inhibitor methylphenidate, and placebo on measures of mood, motivation and cognition in 23 agonist-naïve PD patients and 23 healthy controls. Acute challenge with pramipexole had a negative effect on mood and fatigue in both patients and controls. In addition, challenge with pramipexole led to increased anger, fatigue, vigor and tension in healthy control subjects, but not in PD patients. Challenge with methylphenidate had a positive effect on anhedonia and vigor in PD patients. Due to its side effects after a single administration, pramipexole is probably less suitable for acute challenge studies. The acute effects of a methylphenidate challenge on anhedonia and vigor in PD patients make this drug an interesting choice for further studies of the treatment of mood and motivational disorders in this population. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Evaluation of an experimental and commercial state-of-the-art vaccine against enteric redmouth disease (ERM) in rainbow trout by waterborne challenge with Y. ruckeri O1 biotype 2

    DEFF Research Database (Denmark)

    Kragelund Strøm, Helene; Otani, Maki; Villumsen, Kasper Rømer

    strain obtained from an ERM disease outbreak in a Danish trout farm. This waterborne infection model gives us the opportunity to test and evaluate the effect of commercial and experimental vaccines against Y. ruckeri O1 biotype 2. An experimental vaccine containing equal amounts of Y. ruckeri O1 biotype...... has been compared to a state-of-the-art commercial ERM immersion vaccine (AquaVac® ReleraTM). Un-vaccinated and sham vaccinated rainbow trout were included as controls. Two months post vaccination the rainbow trout were challenged in duplicate with Y. ruckeri O1 biotype 2 by bath. No effect...... of the experimental immersion or bath vaccine was observed in the present study. However, full protection was achieved with i.p. injection of the experimental vaccine (pVac® ReleraTM induced a significant, partial protection relative to the control groups (p=0.002, RPS=58...

  14. Linear Parameter Varying Control of Induction Motors

    DEFF Research Database (Denmark)

    Trangbæk, Klaus

    The subject of this thesis is the development of linear parameter varying (LPV) controllers and observers for control of induction motors. The induction motor is one of the most common machines in industrial applications. Being a highly nonlinear system, it poses challenging control problems...... for high performance applications. This thesis demonstrates how LPV control theory provides a systematic way to achieve good performance for these problems. The main contributions of this thesis are the application of the LPV control theory to induction motor control as well as various contributions...

  15. A new multivalent (DHPPi/L4R) canine combination vaccine prevents infection, shedding and clinical signs following experimental challenge with four Leptospira serovars.

    Science.gov (United States)

    Wilson, Stephen; Stirling, Catrina; Thomas, Anne; King, Vickie; Plevová, Edita; Chromá, Ludmila; Siedek, Elisabeth; Illambas, Joanna; Salt, Jeremy; Sture, Gordon

    2013-06-28

    Although effective vaccines have been developed against the common Leptospira serovars, they are still reported in clinical cases, while others are increasingly prevalent. The results from four challenge studies following vaccination of dogs with a new combination vaccine (DHPPi/L4R) containing inactivated L. serovars, L. canicola, L. icterohaemorrhagiae, L. bratislava and L. grippotyphosa conducted to satisfy the requirements of the European Pharmacopoeia monograph (01/2008:0447), are reported. Six week old dogs received two vaccinations, three weeks apart, and were challenged 25 days later with different isolates of the L. serovars. Clinical observations were recorded, and blood, urine and tissue samples were collected for analysis. Following challenge, non-vaccinated dogs demonstrated various clinical signs, while no vaccinated dogs were affected; significant differences in mean clinical scores were observed. Measurable antibody titres to each Leptospira antigen were seen in vaccinated dogs 21 days following the first vaccination, with further increases in antibody titres observed following challenge with the respective Leptospira strain. Non-vaccinated dogs remained seronegative until challenge. Leptospira were re-isolated from the blood, urine, kidney and liver of all non-vaccinated dogs following challenge. In contrast no vaccinated dogs had Leptospira re-isolated from the same tissues. Significant differences were seen in number of days with positive isolation (blood and urine) and in number of dogs with positive samples (kidney and liver). In conclusion, vaccination of dogs with the new vaccine induces protective immunity 25 days after second vaccination with protection against infection, renal infection and clinical signs following challenge. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Enhancement of heat transfer using varying width twisted tape inserts

    African Journals Online (AJOL)

    International Journal of Engineering, Science and Technology ... experimental investigations of the augmentation of turbulent flow heat transfer in a horizontal tube by means of varying width twisted tape inserts with air as the working fluid.

  17. Application of Doehlert experimental design in the optimization of experimental variables for the Pseudozyma sp. (CCMB 306 and Pseudozyma sp. (CCMB 300 cell lysis Aplicação do modelo Doehlert na otimização das variáveis experimentais para a lise de Pseudozyma sp. (CCMB 306 e Pseudozyma sp. (CCMB 300

    Directory of Open Access Journals (Sweden)

    Amanda Reges de Sena

    2012-12-01

    Full Text Available This study aimed to verify the influence of pH and temperature on the lysis of yeast using experimental design. In this study, the enzymatic extract containing β-1,3-glucanase and chitinase, obtained from the micro-organism Moniliophthora perniciosa, was used. The experiment showed that the best conditions for lysis of Pseudozyma sp. (CCMB 306 and Pseudozyma sp. (CCMB 300 by lytic enzyme were pH 4.9 at 37 ºC and pH 3.9 at 26.7 ºC, respectively. The lytic enzyme may be used for obtaining various biotechnology products from yeast.O presente trabalho visou verificar a influência do pH e temperatura na lise de leveduras utilizando planejamento experimental. No estudo, foi utilizado o extrato enzimático, contendo β-1,3-glucanase e quitinase líticas, obtidas do micro-organismo Moniliophthora perniciosa. O delineamento experimental mostrou que as melhores condições para a lise de Pseudozyma sp. (CCMB 306 e Pseudozyma sp. (CCMB 300, pelas enzimas líticas, foram pH 4,9 a 37 ºC, pH 3,9 a 26,7 ºC, respectivamente. As enzimas líticas podem ser utilizadas para a obtenção de vários produtos biotecnológicos a partir de leveduras.

  18. Foals raised on pasture with or without daily pyrantel tartrate feed additive: comparison of parasite burdens and host responses following experimental challenge with large and small strongyle larvae.

    Science.gov (United States)

    Monahan, C M; Chapman, M R; Taylor, H W; French, D D; Klei, T R

    1997-12-31

    Three groups of foals were raised under different management programs in this study: Group 1 (n = 6) and Group 2 (n = 6) were raised with their dams on pasture; Group 3 foals (n = 5) were raised under parasite-free conditions. Mares and foals of Group 1 received daily pyrantel tartrate (PT) treatment with their pelleted feed ration, whereas mares and foals of Groups 2 and 3 received only the pelleted ration. Pasture-reared foals were weaned and moved to a heavily contaminated pasture for 5 weeks. Group 1 foals continued to receive daily PT treatment whereas Group 2 foals received only the pelleted feed ration. Following this period, all foals were moved into box stalls. Half of each group was challenged with 10(3) Strongylus vulgaris infective third-stage larvae (L3), 5 x 10(3) Strongylus edentatus L3 and 10(5) mixed cyathostome L3; the remaining half served as unchallenged controls. Necropsy examinations were performed 6-week post-challenge for evaluation of parasite burdens and lesions. Daily PT treatment of Group 1 reduced the patent cyathostome infections of both mares and foals and was effective in reducing pasture burdens of infective larvae. Daily treatment of Group 1 foals during weaning continued to suppress EPG levels; however, it did not prevent large strongyle infections during the weaning period. Group 1 foals were more sensitive to challenge than Group 2 foals, which did not exhibit any post-challenge disturbances. Group 1 foals were equally susceptible to challenge as parasite-free foals.

  19. Time-varying Crash Risk

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

    We estimate a continuous-time model with stochastic volatility and dynamic crash probability for the S&P 500 index and find that market illiquidity dominates other factors in explaining the stock market crash risk. While the crash probability is time-varying, its dynamic depends only weakly on re...

  20. Eestlased Karlovy Varys / J. R.

    Index Scriptorium Estoniae

    J. R.

    2007-01-01

    Ilmar Raagi mängufilm "Klass" osaleb 42. Karlovy Vary rahvusvahelise filmifestivali võistlusprogrammis "East of the West" ja Asko Kase lühimängufilm "Zen läbi prügi" on valitud festivali kõrvalprogrammi "Forum of Independents"

  1. Esmaklassiline Karlovy Vary / Jaanus Noormets

    Index Scriptorium Estoniae

    Noormets, Jaanus

    2007-01-01

    Ilmar Raagi mängufilm "Klass" võitis 42. Karlovy Vary rahvusvahelise filmifestivalil kaks auhinda - ametliku kõrvalvõistlusprogrammi "East of the West" eripreemia "Special mention" ja Euroopa väärtfilmikinode keti Europa Cinemas preemia. Ka Asko Kase lühifilmi "Zen läbi prügi linastumisest ning teistest auhinnasaajatest ning osalejatest

  2. Optimistlik Karlovy Vary / Jaan Ruus

    Index Scriptorium Estoniae

    Ruus, Jaan, 1938-2017

    2007-01-01

    42. Karlovy Vary rahvusvahelise filmifestivali auhinnatud filmidest (žürii esimees Peter Bart). Kristallgloobuse sai Islandi-Saksamaa "Katseklaasilinn" (režii Baltasar Kormakur), parimaks režissööriks tunnistati norralane Bard Breien ("Negatiivse mõtlemise kunst"). Austraallase Michael James Rowlandi "Hea õnne teekond" sai žürii eripreemia

  3. Science as Knowledge, Practice, and Map Making: The Challenge of Defining Metrics for Evaluating and Improving DOE-Funded Basic Experimental Science

    Energy Technology Data Exchange (ETDEWEB)

    Bodnarczuk, M.

    1993-03-01

    Industrial R&D laboratories have been surprisingly successful in developing performance objectives and metrics that convincingly show that planning, management, and improvement techniques can be value-added to the actual output of R&D organizations. In this paper, I will discuss the more difficult case of developing analogous constructs for DOE-funded non-nuclear, non-weapons basic research, or as I will refer to it - basic experimental science. Unlike most industrial R&D or the bulk of applied science performed at the National Renewable Energy Laboratory (NREL), the purpose of basic experimental science is producing new knowledge (usually published in professional journals) that has no immediate application to the first link (the R) of a planned R&D chain. Consequently, performance objectives and metrics are far more difficult to define. My claim is that if one can successfully define metrics for evaluating and improving DOE-funded basic experimental science (which is the most difficult case), then defining such constructs for DOE-funded applied science should be much less problematic. With the publication of the DOE Standard - Implementation Guide for Quality Assurance Programs for Basic and Applied Research (DOE-ER-STD-6001-92) and the development of a conceptual framework for integrating all the DOE orders, we need to move aggressively toward the threefold next phase: (1) focusing the management elements found in DOE-ER-STD-6001-92 on the main output of national laboratories - the experimental science itself; (2) developing clearer definitions of basic experimental science as practice not just knowledge; and (3) understanding the relationship between the metrics that scientists use for evaluating the performance of DOE-funded basic experimental science, the management elements of DOE-ER-STD-6001-92, and the notion of continuous improvement.

  4. A Comparison of Experimental Functional Analysis and the Questions about Behavioral Function (QABF) in the Assessment of Challenging Behavior of Individuals with Autism

    Science.gov (United States)

    Healy, Olive; Brett, Denise; Leader, Geraldine

    2013-01-01

    We compared two functional behavioral assessment methods: the Questions About Behavioral Function (QABF; a standardized test) and experimental functional analysis (EFA) to identify behavioral functions of aggressive/destructive behavior, self-injurious behavior and stereotypy in 32 people diagnosed with autism. Both assessments found that self…

  5. Genetic polymorphisms in varied environments.

    Science.gov (United States)

    Powell, J R

    1971-12-03

    Thirteen experimenital populationis of Drosophila willistoni were maintained in cages, in some of which the environments were relatively constant and in others varied. After 45 weeks, the populations were assayed by gel electrophoresis for polymorphisms at 22 protein loci. The average heterozygosity per individual and the average unmber of alleles per locus were higher in populations maintained in heterogeneous environments than in populations in more constant enviroments.

  6. Anistropically varying conductivity in irreversible electroporation simulations.

    Science.gov (United States)

    Labarbera, Nicholas; Drapaca, Corina

    2017-11-01

    One recent area of cancer research is irreversible electroporation (IRE). Irreversible electroporation is a minimally invasive procedure where needle electrodes are inserted into the body to ablate tumor cells with electricity. The aim of this paper is to propose a mathematical model that incorporates a tissue's conductivity increasing more in the direction of the electrical field as this has been shown to occur in experiments. It was necessary to mathematically derive a valid form of the conductivity tensor such that it is dependent on the electrical field direction and can be easily implemented into numerical software. The derivation of a conductivity tensor that can take arbitrary functions for the conductivity in the directions tangent and normal to the electrical field is the main contribution of this paper. Numerical simulations were performed for isotropic-varying and anisotropic-varying conductivities to evaluate the importance of including the electrical field's direction in the formulation for conductivity. By starting from previously published experimental results, this paper derived a general formulation for an anistropic-varying tensor for implementation into irreversible electroporation modeling software. The anistropic-varying tensor formulation allows the conductivity to take into consideration both electrical field direction and magnitude, as opposed to previous published works that only took into account electrical field magnitude. The anisotropic formulation predicts roughly a five percent decrease in ablation size for the monopolar simulation and approximately a ten percent decrease in ablation size for the bipolar simulations. This is a positive result as previously reported results found the isotropic formulation to overpredict ablation size for both monopolar and bipolar simulations. Furthermore, it was also reported that the isotropic formulation overpredicts the ablation size more for the bipolar case than the monopolar case. Thus, our

  7. Effect of Various Inoculum Levels of Multidrug-Resistant Salmonella enterica Serovar Heidelberg (2011 Ground Turkey Outbreak Isolate on Cecal Colonization, Dissemination to Internal Organs, and Deposition in Skeletal Muscles of Commercial Turkeys after Experimental Oral Challenge

    Directory of Open Access Journals (Sweden)

    Divek V. T. Nair

    2018-01-01

    Full Text Available Salmonella enterica serovar Heidelberg (S. Heidelberg is a major foodborne pathogen colonizing poultry. The pathogen is associated with a significant number of foodborne outbreaks through contaminated poultry meat, including turkeys. Recently, multidrug-resistant (MDR strains of S. Heidelberg have emerged as a threat to human public health in the United States. The objective of this study was to determine the cecal colonization, dissemination to internal organs, and the potential for skeletal muscle deposition of an MDR S. Heidelberg isolate from the 2011 ground turkey outbreak in the United States after the experimental oral challenge of poults (young turkeys and adult turkey hens. In the poult study, two separate experiments using day-old, straight-run, commercial hybrid converter poults were randomly assigned to five challenge groups (0, 10∧2, 10∧4, 10∧6, 10∧8 CFU groups; 12 poults/group; N = 60/experiment and a week after, treatment groups were challenged separately with 0-, 2-, 4-, 6-, and 8- log10 CFU of S. Heidelberg orally. After 14 days post-challenge, the poults were euthanized, and samples were collected to determine MDR S. Heidelberg colonization in the cecum, dissemination to liver and spleen, and deposition in the thigh, drumstick, and breast muscles. A similar experimental design was followed for the adult turkey hens. In two separate experiments, 11-week-old commercial Hybrid Converter turkey hens (4 hens/group; N = 20/experiment were challenged with MDR S. Heidelberg and on day 16 post-challenge, birds were euthanized and samples were collected to determine Salmonella populations in the samples. The results indicated that, in turkey poults, the recovery of MDR S. Heidelberg was highest in the cecum followed by spleen, liver, thigh, drumstick, and breast. All tested inoculum levels resulted in more than 3.5 log10 CFU/g colonization in the poult cecum. The cecal colonization, dissemination to internal organs, and tissue

  8. Introduction: Experimental Green Strategies

    DEFF Research Database (Denmark)

    Peters, Terri

    2011-01-01

    Defining new ways in which archietcts are responding to the challenge of creating sustainable architecture , Experimental Green Strategies present a state of the art in applied ecological architectural research.......Defining new ways in which archietcts are responding to the challenge of creating sustainable architecture , Experimental Green Strategies present a state of the art in applied ecological architectural research....

  9. Progress on MEVVA source VARIS at GSI

    Science.gov (United States)

    Adonin, A.; Hollinger, R.

    2018-05-01

    For the last few years, the development of the VARIS (vacuum arc ion source) was concentrated on several aspects. One of them was the production of high current ion beams of heavy metals such as Au, Pb, and Bi. The requested ion charge state for these ion species is 4+. This is quite challenging to produce in vacuum arc driven sources for reasonable beam pulse length (>120 µs) due to the physical properties of these elements. However, the situation can be dramatically improved by using the composite materials or alloys with enhanced physical properties of the cathodes. Another aspect is an increase of the beam brilliance for intense U4+ beams by the optimization of the geometry of the extraction system. A new 7-hole triode extraction system allows an increase of the extraction voltage from 30 kV to 40 kV and also reduces the outer aperture of the extracted ion beam. Thus, a record beam brilliance for the U4+ beam in front of the RFQ (Radio-Frequency Quadrupole) has been achieved, exceeding the RFQ space charge limit for an ion current of 15 mA. Several new projectiles in the middle-heavy region have been successfully developed from VARIS to fulfill the requirements of the future FAIR (Facility for Antiproton and Ion Research) programs. An influence of an auxiliary gas on the production performance of certain ion charge states as well as on operation stability has been investigated. The optimization of the ion source parameters for a maximum production efficiency and highest particle current in front of the RFQ has been performed. The next important aspect of the development will be the increase of the operation repetition rate of VARIS for all elements especially for uranium to 2.7 Hz in order to provide the maximum availability of high current ion beams for future FAIR experiments.

  10. Weighted approximation with varying weight

    CERN Document Server

    Totik, Vilmos

    1994-01-01

    A new construction is given for approximating a logarithmic potential by a discrete one. This yields a new approach to approximation with weighted polynomials of the form w"n"(" "= uppercase)P"n"(" "= uppercase). The new technique settles several open problems, and it leads to a simple proof for the strong asymptotics on some L p(uppercase) extremal problems on the real line with exponential weights, which, for the case p=2, are equivalent to power- type asymptotics for the leading coefficients of the corresponding orthogonal polynomials. The method is also modified toyield (in a sense) uniformly good approximation on the whole support. This allows one to deduce strong asymptotics in some L p(uppercase) extremal problems with varying weights. Applications are given, relating to fast decreasing polynomials, asymptotic behavior of orthogonal polynomials and multipoint Pade approximation. The approach is potential-theoretic, but the text is self-contained.

  11. Estrelas variáveis

    OpenAIRE

    Viana, Sérgio Manuel de Oliveira

    2001-01-01

    A observação do céu nocturno é uma prática que vem da Antiguidade. Desde então e durante muito tempo pensou-se que as estrelas mantinham o brilho constante. Assim foi até ao século XVI, quando David Fabricius observou uma estrela cujo brilho variava periodicamente. Dois séculos mais tarde, Jonh Goodricke descobriu uma segunda estrela e com o desenvolvimento de instrumentos de observação este conjunto foi muito alargado e hoje inclui o Sol.A variação do brilho das estrelas variáveis permite d...

  12. Vaccination of Elk (Cervus canadensis) with Brucella abortus Strain RB51 Overexpressing Superoxide Dismutase and Glycosyltransferase Genes Does Not Induce Adequate Protection against Experimental Brucella abortus Challenge.

    Science.gov (United States)

    Nol, Pauline; Olsen, Steven C; Rhyan, Jack C; Sriranganathan, Nammalwar; McCollum, Matthew P; Hennager, Steven G; Pavuk, Alana A; Sprino, Phillip J; Boyle, Stephen M; Berrier, Randall J; Salman, Mo D

    2016-01-01

    In recent years, elk (Cervus canadensis) have been implicated as the source of Brucella abortus infection for numerous cattle herds in the Greater Yellowstone Area. In the face of environmental and ecological changes on the landscape, the range of infected elk is expanding. Consequently, the development of effective disease management strategies for wild elk herds is of utmost importance, not only for the prevention of reintroduction of brucellosis to cattle, but also for the overall health of the Greater Yellowstone Area elk populations. In two studies, we evaluated the efficacy of B. abortus strain RB51 over-expressing superoxide dismutase and glycosyltransferase for protecting elk from infection and disease caused by B. abortus after experimental infection with a virulent B. abortus strain. Our data indicate that the recombinant vaccine does not protect elk against brucellosis. Further, work is needed for development of an effective brucellosis vaccine for use in elk.

  13. Abalone viral ganglioneuritis: establishment and use of an experimental immersion challenge system for the study of abalone herpes virus infections in Australian abalone.

    Science.gov (United States)

    Corbeil, Serge; McColl, Kenneth A; Williams, Lynette M; Mohammad, Ilhan; Hyatt, Alexander D; Crameri, Sandra G; Fegan, Mark; Crane, Mark St J

    2012-05-01

    In late 2005, acute mortalities occurred in abalone on farms located in Victoria, Australia. Disease was associated with infection by an abalone herpes virus (AbHV). Subsequently, starting in 2006, the disease (abalone viral ganglioneuritis; AVG) was discovered in wild abalone in Victorian open waters. Currently, it continues to spread, albeit at a slow rate, along the Victorian coast-line. Here, we report on experimental transmission trials that were carried out by immersion using water into which diseased abalone had shed infectious viral particles. At various time points following exposure, naïve abalone were assessed by an AbHV-specific real-time PCR and histological analyses including in situ hybridization (ISH). Results demonstrated that while exposed abalone began displaying clinical signs of the disease from 60 hours post exposure (hpe), they tested positive for the presence of viral DNA at 36 hpe. Of further interest, the AbHV DNA probe used in the ISH assay detected the virus as early as 48 hpe. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  14. Cognitive Challenges

    Science.gov (United States)

    ... Privacy Policy Sitemap Learn Engage Donate About TSC Cognitive Challenges Approximately 45% to 60% of individuals with TSC develop cognitive challenges (intellectual disabilities), although the degree of intellectual ...

  15. Time varying, multivariate volume data reduction

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, James P [Los Alamos National Laboratory; Fout, Nathaniel [UC DAVIS; Ma, Kwan - Liu [UC DAVIS

    2010-01-01

    Large-scale supercomputing is revolutionizing the way science is conducted. A growing challenge, however, is understanding the massive quantities of data produced by large-scale simulations. The data, typically time-varying, multivariate, and volumetric, can occupy from hundreds of gigabytes to several terabytes of storage space. Transferring and processing volume data of such sizes is prohibitively expensive and resource intensive. Although it may not be possible to entirely alleviate these problems, data compression should be considered as part of a viable solution, especially when the primary means of data analysis is volume rendering. In this paper we present our study of multivariate compression, which exploits correlations among related variables, for volume rendering. Two configurations for multidimensional compression based on vector quantization are examined. We emphasize quality reconstruction and interactive rendering, which leads us to a solution using graphics hardware to perform on-the-fly decompression during rendering. In this paper we present a solution which addresses the need for data reduction in large supercomputing environments where data resulting from simulations occupies tremendous amounts of storage. Our solution employs a lossy encoding scheme to acrueve data reduction with several options in terms of rate-distortion behavior. We focus on encoding of multiple variables together, with optional compression in space and time. The compressed volumes can be rendered directly with commodity graphics cards at interactive frame rates and rendering quality similar to that of static volume renderers. Compression results using a multivariate time-varying data set indicate that encoding multiple variables results in acceptable performance in the case of spatial and temporal encoding as compared to independent compression of variables. The relative performance of spatial vs. temporal compression is data dependent, although temporal compression has the

  16. Steady shear viscosity of stirred yoghurts with varying ropiness

    NARCIS (Netherlands)

    van Marle, M.E.; van Marle, M.E.; van den Ende, Henricus T.M.; de Kruif, C.G.; de Kruif, C.G.; Mellema, J.

    1999-01-01

    Stirred yogurt was viewed as a concentrated dispersion of aggregates consisting of protein particles. The steady-shear behavior of three types of stirred yogurt with varying ropiness was investigated experimentally. To describe the shear-dependent viscosity, a microrheological model was used which

  17. Overcoming challenges

    Medline Plus

    Full Text Available ... breastfeeding Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch Finding ... myths Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch Finding ...

  18. Overcoming challenges

    Medline Plus

    Full Text Available ... section Back to section menu It's Only Natural Planning ahead Breastfeeding and baby basics Making breastfeeding work ... It's Only Natural Overcoming challenges It's Only Natural Planning ahead Addressing breastfeeding myths Overcoming challenges Common questions ...

  19. Flavobacterium psychrophilum - Experimental challenge and immune response

    DEFF Research Database (Denmark)

    Henriksen, Maya Maria Mihályi

    the immune system of the fry is not fully developed. Theoretically, the infection pressure could be subdued by vaccinating larger fish, but no commercial vaccine is yet available. Diagnostic methods are well described and the disease is treated with antibiotics. To prevent disease outbreaks and subsequent......-time PCR (RT-PCR) was used to examine the immune response in the head kidney during the first eight days after infection, and enzyme-linked immunosorbent assay (ELISA) was used to evaluate the production of antibodies 50 days post-exposure. A pro-inflammatory response was observed in both groups infected...... of edemas, but in both cases the tissue was regenerating after 192 hours. However, when the fish had been exposed to both H2O2 and F. psychrophilum, the damage was still evident at this time point. The relative pathogen load measured as 16S rRNA was highest at the first sampling and decreased steadily...

  20. A varying-α brane world cosmology

    International Nuclear Information System (INIS)

    Youm, Donam

    2001-08-01

    We study the brane world cosmology in the RS2 model where the electric charge varies with time in the manner described by the varying fine-structure constant theory of Bekenstein. We map such varying electric charge cosmology to the dual variable-speed-of-light cosmology by changing system of units. We comment on cosmological implications for such cosmological models. (author)

  1. Antiorthostatic immobilization with varied sodium intake

    Science.gov (United States)

    Hinghofer-Szalkay, H.; Haditsch, B.; Pilz, K.; Rössler, A.; Laszlo, Z.

    The study investigated, in 10 normotensive male persons, heart rate responses to graded lower body suction (LBNP) with adaptation to various oral sodium clamping during both ambulatory (AMB) conditions for 4 days, and thereafter to additional antiorthostatic (6° head down) positioning. A ,low' (LS: 143+/-10 mM Na +/ d excreted) and a ,high' (HS: 434+/-17 mM Na +/d excreted) sodium treatment - in randomized order and separated =1 mo - followed a ,conditioning' run with moderate sodium (237+/-9 mM Na +/d excreted). Urinary volume and sodium output were monitored, hormone levels (PRA, aldosterone, AVP) determined, and extracellular volume (ECV) estimated by whole body electrical impedance spectroscopy. ECV was not differently reduced (p>0.1) in LS (-5.8+/-2.3%, p=0.018) and HS (-4.0+/-1.0%. p=0.002). Morning AVP was lower (5.5+/-0.1 pg/ml) in HS than in LS (7.2+/-0.3 pg/ml; N=7 days), as well as aldosterone (69+/-7 pg/ml in HS vs. 180+/-24 pg/ml in LS). LBNP dose responses of PRA and aldosterone were higher in LS than HS after 8 days AOB, whereas microvascular fluid filtration was unchanged by any experimental condition. Heart rate responses to LBNP were unchanged by sodium supply, whereas mean arterial and pulse pressure was lower in LS than HS during all LBNP intensities. Thus, HS was able to increase arterial blood and pulse pressure and reduced PRA and aldosterone levels during graded simulated orthostatic challenge, but did neither ameliorate AOB-induced ECV decrease nor alter LBNP-induced filtration and heart rate responses. These results are relevant for planning of future countermeasures in astronauts. Supported by the Austrian Research Fund (P13451-MED)

  2. Overcoming challenges

    Medline Plus

    Full Text Available ... Disease and Stroke HIV and AIDS Mental Health Pain Pregnancy Reproductive Health Sexual Health Sexually Transmitted Infections ... breastfeeding Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch ...

  3. Overcoming challenges

    Medline Plus

    Full Text Available ... menu It's Only Natural Planning ahead Breastfeeding and baby basics Making breastfeeding work for you Addressing breastfeeding ... in the African-American community Incredible facts about babies, breastmilk, and breastfeeding Overcoming challenges Common questions about ...

  4. Overcoming challenges

    Medline Plus

    Full Text Available ... facts about babies, breastmilk, and breastfeeding Overcoming challenges Common questions about breastfeeding and pain Breastfeeding checklist: How to get a good latch Finding support It takes a village: Building ...

  5. Cognitive Challenges

    Science.gov (United States)

    ... Alliance Our Story Our Vision Our Team Our Leadership Our Results Our Corporate Policies FAQs Careers Contact Us Media Store Privacy Policy Sitemap Learn Engage Donate About TSC Cognitive Challenges Approximately 45% to 60% of individuals with TSC ...

  6. Overcoming challenges

    Medline Plus

    Full Text Available ... breastfeeding means to them. Subscribe To receive Breastfeeding email updates Enter email Submit Overcoming challenges Breastfeeding has a long list ... breastfeeding means to them. Subscribe To receive Breastfeeding email updates Enter email Submit All material contained on ...

  7. Overcoming challenges

    Medline Plus

    Full Text Available ... into your life Breastfeeding in daily life: At home and in public Laws that support breastfeeding 10 ... and jobs View all pages in this section Home It's Only Natural Overcoming challenges It's Only Natural ...

  8. Eesti film võistleb Karlovy Varys

    Index Scriptorium Estoniae

    2008-01-01

    8. juulil esilinastub Karlovy Vary filmifestivalil Rene Vilbre noortefilm "Mina olin siin", mille aluseks on Sass Henno romaan "Mina olin siin. Esimene arest", stsenaariumi kirjutas Ilmar Raag. Film võistleb võistlusprogrammis "East of the West"

  9. Matching Value Propositions with Varied Customer Needs

    DEFF Research Database (Denmark)

    Heikka, Eija-Liisa; Frandsen, Thomas; Hsuan, Juliana

    2018-01-01

    Organizations seek to manage varied customer segments using varied value propositions. The ability of a knowledge-intensive business service (KIBS) provider to formulate value propositions into attractive offerings to varied customers becomes a competitive advantage. In this specific business based...... on often highly abstract service offerings, this requires the provider to have a clear overview of its knowledge and resources and how these can be configured to obtain the desired customization of services. Hence, the purpose of this paper is to investigate how a KIBS provider can match value propositions...... with varied customer needs utilizing service modularity. To accomplish this purpose, a qualitative multiple case study is organized around 5 projects allowing within-case and cross-case comparisons. Our findings describe how through the configuration of knowledge and resources a sustainable competitive...

  10. Compilation of Instantaneous Source Functions for Varying ...

    African Journals Online (AJOL)

    Compilation of Instantaneous Source Functions for Varying Architecture of a Layered Reservoir with Mixed Boundaries and Horizontal Well Completion Part III: B-Shaped Architecture with Vertical Well in the Upper Layer.

  11. Compilation of Instantaneous Source Functions for Varying ...

    African Journals Online (AJOL)

    Compilation of Instantaneous Source Functions for Varying Architecture of a Layered Reservoir with Mixed Boundaries and Horizontal Well Completion Part IV: Normal and Inverted Letter 'h' and 'H' Architecture.

  12. Fluctuating interaction network and time-varying stability of a natural fish community

    Science.gov (United States)

    Ushio, Masayuki; Hsieh, Chih-Hao; Masuda, Reiji; Deyle, Ethan R.; Ye, Hao; Chang, Chun-Wei; Sugihara, George; Kondoh, Michio

    2018-02-01

    Ecological theory suggests that large-scale patterns such as community stability can be influenced by changes in interspecific interactions that arise from the behavioural and/or physiological responses of individual species varying over time. Although this theory has experimental support, evidence from natural ecosystems is lacking owing to the challenges of tracking rapid changes in interspecific interactions (known to occur on timescales much shorter than a generation time) and then identifying the effect of such changes on large-scale community dynamics. Here, using tools for analysing nonlinear time series and a 12-year-long dataset of fortnightly collected observations on a natural marine fish community in Maizuru Bay, Japan, we show that short-term changes in interaction networks influence overall community dynamics. Among the 15 dominant species, we identify 14 interspecific interactions to construct a dynamic interaction network. We show that the strengths, and even types, of interactions change with time; we also develop a time-varying stability measure based on local Lyapunov stability for attractor dynamics in non-equilibrium nonlinear systems. We use this dynamic stability measure to examine the link between the time-varying interaction network and community stability. We find seasonal patterns in dynamic stability for this fish community that broadly support expectations of current ecological theory. Specifically, the dominance of weak interactions and higher species diversity during summer months are associated with higher dynamic stability and smaller population fluctuations. We suggest that interspecific interactions, community network structure and community stability are dynamic properties, and that linking fluctuating interaction networks to community-level dynamic properties is key to understanding the maintenance of ecological communities in nature.

  13. Environmental challenge

    International Nuclear Information System (INIS)

    Conable, B.; Warford, J.; Partow, Z.; Lutz, E.; Munasinghe, M.

    1991-09-01

    The contents include the following: Development and the Environment: A Global Balance; Evolution of the World Bank's Environmental Policy; Accounting for the Environment; Public Policy and the Environment; Managing Drylands; Environmental Action Plans in Africa; Agroforestry in Sub-Saharan Africa; Irrigation and the Environmental Challenge; Curbing Pollution in Developing Countries; Global Warming and the Developing World; and The Global Environment Facility

  14. Challenging Identities

    DEFF Research Database (Denmark)

    depends on the conceptual or ideological constellation in which it takes part. This volume on one hand demonstrates the role of notions of identity in a variety of European contexts, and on the other hand highlights how there may be reasons to challenge the use of the term and corresponding social...

  15. Overcoming challenges

    Medline Plus

    Full Text Available ... Contact Us Blog Popular topics Vision and mission Leadership Programs and activities In your community Funding opportunities Internships and jobs View all pages in this section Home It's Only Natural Overcoming challenges It's Only Natural Planning ahead Addressing breastfeeding myths ...

  16. Overcoming challenges

    Medline Plus

    Full Text Available ... we are What we do Programs and activities Work with us Contact Us Blog Popular topics Vision and mission Leadership Programs and activities In your community Funding opportunities Internships and jobs View all pages in this section Home It's Only Natural Overcoming challenges It's Only Natural ...

  17. Varying constants, black holes, and quantum gravity

    International Nuclear Information System (INIS)

    Carlip, S.

    2003-01-01

    Tentative observations and theoretical considerations have recently led to renewed interest in models of fundamental physics in which certain 'constants' vary in time. Assuming fixed black hole mass and the standard form of the Bekenstein-Hawking entropy, Davies, Davis and Lineweaver have argued that the laws of black hole thermodynamics disfavor models in which the fundamental electric charge e changes. I show that with these assumptions, similar considerations severely constrain 'varying speed of light' models, unless we are prepared to abandon cherished assumptions about quantum gravity. Relaxation of these assumptions permits sensible theories of quantum gravity with ''varying constants,'' but also eliminates the thermodynamic constraints, though the black hole mass spectrum may still provide some restrictions on the range of allowable models

  18. Mobility Challenges

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lassen, Claus

    2011-01-01

    This article takes point of departure in the challenges to understand the importance of contemporary mobility. The approach advocated is a cross-disciplinary one drawing on sociology, geography, urban planning and design, and cultural studies. As such the perspective is to be seen as a part...... of the so-called ‘mobility turn’ within social science. The perspective is illustrative for the research efforts at the Centre for Mobility and Urban Studies (C-MUS), Aalborg University. The article presents the contours of a theoretical perspective meeting the challenges to research into contemporary urban...... mobilities. In particular the article discusses 1) the physical city, its infrastructures and technological hardware/software, 2) policies and planning strategies for urban mobility and 3) the lived everyday life in the city and the region....

  19. "Mina olin siin" esilinastub Karlovy Varys

    Index Scriptorium Estoniae

    2008-01-01

    Karlovy Vary filmifestivalil esilinastub Rene Vilbre noortefilm "Mina olin siin", mille aluseks on Sass Henno romaan "Mina olin siin. Esimene arest", stsenaariumi kirjutas Ilmar Raag. Film võistleb võistlusprogrammis "East of the West". Esitlema sõidavad R. Vilbre, R. Sildos, R. Kaljujärv, T. Tuisk

  20. Tracking time-varying coefficient-functions

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Nielsen, Torben Skov; Joensen, Alfred K.

    2000-01-01

    is a combination of recursive least squares with exponential forgetting and local polynomial regression. It is argued, that it is appropriate to let the forgetting factor vary with the value of the external signal which is the argument of the coefficient functions. Some of the key properties of the modified method...... are studied by simulation...

  1. Filmihullu eluvesi voolab Karlovy Varys / Margit Tõnson

    Index Scriptorium Estoniae

    Tõnson, Margit, 1978-

    2010-01-01

    Karlovy Vary rahvusvahelisest filmifestivalist. Filmidest "Mr. Nobody" (rež. Jaco Van Dormaeli), "Kasside ema Teresa" (rež. Pawel Sala) ja "The Arbor" (rež. Clio Barnardi). Nimekiri võitnud töödest ja viimastel aastatel festivalil näidatud Eesti mängufilmidest

  2. Ellipsometry with randomly varying polarization states

    NARCIS (Netherlands)

    Liu, F.; Lee, C. J.; Chen, J. Q.; E. Louis,; van der Slot, P. J. M.; Boller, K. J.; F. Bijkerk,

    2012-01-01

    We show that, under the right conditions, one can make highly accurate polarization-based measurements without knowing the absolute polarization state of the probing light field. It is shown that light, passed through a randomly varying birefringent material has a well-defined orbit on the Poincar

  3. Õunpuu Karlovy Varys edukas

    Index Scriptorium Estoniae

    2010-01-01

    45. Karlovy Vary filmifestivali võistlusprogrammis "East of the West" märgiti ära Veiko Õunpuu film "Püha Tõnu kiusamine". Peaauhind läks rumeenlase Cristi Puiu filmile "Aurora". Grand prix´sai Augustĺ Vila film "La mosquitera". Teisi preemiasaajaid

  4. Vesicle biomechanics in a time-varying magnetic field.

    Science.gov (United States)

    Ye, Hui; Curcuru, Austen

    2015-01-01

    Cells exhibit distortion when exposed to a strong electric field, suggesting that the field imposes control over cellular biomechanics. Closed pure lipid bilayer membranes (vesicles) have been widely used for the experimental and theoretical studies of cellular biomechanics under this electrodeformation. An alternative method used to generate an electric field is by electromagnetic induction with a time-varying magnetic field. References reporting the magnetic control of cellular mechanics have recently emerged. However, theoretical analysis of the cellular mechanics under a time-varying magnetic field is inadequate. We developed an analytical theory to investigate the biomechanics of a modeled vesicle under a time-varying magnetic field. Following previous publications and to simplify the calculation, this model treated the inner and suspending media as lossy dielectrics, the membrane thickness set at zero, and the electric resistance of the membrane assumed to be negligible. This work provided the first analytical solutions for the surface charges, electric field, radial pressure, overall translational forces, and rotational torques introduced on a vesicle by the time-varying magnetic field. Frequency responses of these measures were analyzed, particularly the frequency used clinically by transcranial magnetic stimulation (TMS). The induced surface charges interacted with the electric field to produce a biomechanical impact upon the vesicle. The distribution of the induced surface charges depended on the orientation of the coil and field frequency. The densities of these charges were trivial at low frequency ranges, but significant at high frequency ranges. The direction of the radial force on the vesicle was dependent on the conductivity ratio between the vesicle and the medium. At relatively low frequencies (biomechanics under a time-varying magnetic field. Biological effects of clinical TMS are not likely to occur via alteration of the biomechanics of brain

  5. Diabetes and Menopause: A Twin Challenge

    Science.gov (United States)

    Diabetes and menopause: A twin challenge Diabetes and menopause may team up for varied effects on your body. Here's what to ... to stay in control. By Mayo Clinic Staff Menopause — and the years leading up to it — may ...

  6. Global challenges

    International Nuclear Information System (INIS)

    Blix, H.

    1990-01-01

    A major challenge now facing the world is the supply of energy needed for growth and development in a manner which is not only economically viable but also environmentally acceptable and sustainable in view of the demands of and risks to future generations. The internationally most significant pollutants from energy production through fossil fuels are SO 2 and NO x which cause acid rain, and CO 2 which is the most significant contributor to the greenhouse effect. Nuclear power, now providing about 17% of the world's electricity and 5% of the primary energy already is making a notable contribution to avoiding these emissions. While the industrialized countries will need more energy and especially electricity in the future, the needs of the developing countries are naturally much larger and present a tremendous challenge to the shaping of the world's future energy supply system. The advanced countries will have to accept special responsibilities, as they can most easily use advanced technologies and they have been and remain the main contributors to the environmental problems we now face. Energy conservation and resort to new renewable energy sources, though highly desirable, appear inadequate alone to meet the challenges. The world can hardly afford to do without an increased use of nuclear power, although it is strongly contested in many countries. The objections raised against the nuclear option focus on safety, waste management and disposal problems and the risk for proliferation of nuclear weapons. These issues are not without their problems. The risk of proliferation exists but will not appreciably diminish with lesser global reliance on nuclear power. The waste issue is more of a political than a technical problem. The use of nuclear power, or any other energy source, will never be at zero risk, but the risks are constantly reduced by new techniques and practices. The IAEA sees it as one of its priority tasks to promote such techniques. (author)

  7. Varied line-space gratings and applications

    International Nuclear Information System (INIS)

    McKinney, W.R.

    1991-01-01

    This paper presents a straightforward analytical and numerical method for the design of a specific type of varied line-space grating system. The mathematical development will assume plane or nearly-plane spherical gratings which are illuminated by convergent light, which covers many interesting cases for synchrotron radiation. The gratings discussed will have straight grooves whose spacing varies across the principal plane of the grating. Focal relationships and formulae for the optical grating-pole-to-exist-slit distance and grating radius previously presented by other authors will be derived with a symbolic algebra system. It is intended to provide the optical designer with the tools necessary to design such a system properly. Finally, some possible advantages and disadvantages for application to synchrotron to synchrotron radiation beamlines will be discussed

  8. The Thermal Collector With Varied Glass Covers

    International Nuclear Information System (INIS)

    Luminosu, I.; Pop, N.

    2010-01-01

    The thermal collector with varied glass covers represents an innovation realized in order to build a collector able to reach the desired temperature by collecting the solar radiation from the smallest surface, with the highest efficiency. In the case of the thermal collector with variable cover glasses, the number of the glass plates covering the absorber increases together with the length of the circulation pipe for the working fluid. The thermal collector with varied glass covers compared to the conventional collector better meet user requirements because: for the same temperature increase, has the collecting area smaller; for the same collection area, realizes the highest temperature increase and has the highest efficiency. This works is addressed to researchers in the solar energy and to engineers responsible with air-conditioning systems design or industrial and agricultural products drying.

  9. Spatially varying dispersion to model breakthrough curves.

    Science.gov (United States)

    Li, Guangquan

    2011-01-01

    Often the water flowing in a karst conduit is a combination of contaminated water entering at a sinkhole and cleaner water released from the limestone matrix. Transport processes in the conduit are controlled by advection, mixing (dilution and dispersion), and retention-release. In this article, a karst transport model considering advection, spatially varying dispersion, and dilution (from matrix seepage) is developed. Two approximate Green's functions are obtained using transformation of variables, respectively, for the initial-value problem and for the boundary-value problem. A numerical example illustrates that mixing associated with strong spatially varying conduit dispersion can cause strong skewness and long tailing in spring breakthrough curves. Comparison of the predicted breakthrough curve against that measured from a dye-tracing experiment between Ames Sink and Indian Spring, Northwest Florida, shows that the conduit dispersivity can be as large as 400 m. Such a large number is believed to imply strong solute interaction between the conduit and the matrix and/or multiple flow paths in a conduit network. It is concluded that Taylor dispersion is not dominant in transport in a karst conduit, and the complicated retention-release process between mobile- and immobile waters may be described by strong spatially varying conduit dispersion. Copyright © 2010 The Author(s). Journal compilation © 2010 National Ground Water Association.

  10. New varying speed of light theories

    CERN Document Server

    Magueijo, J

    2003-01-01

    We review recent work on the possibility of a varying speed of light (VSL). We start by discussing the physical meaning of a varying $c$, dispelling the myth that the constancy of $c$ is a matter of logical consistency. We then summarize the main VSL mechanisms proposed so far: hard breaking of Lorentz invariance; bimetric theories (where the speeds of gravity and light are not the same); locally Lorentz invariant VSL theories; theories exhibiting a color dependent speed of light; varying $c$ induced by extra dimensions (e.g. in the brane-world scenario); and field theories where VSL results from vacuum polarization or CPT violation. We show how VSL scenarios may solve the cosmological problems usually tackled by inflation, and also how they may produce a scale-invariant spectrum of Gaussian fluctuations, capable of explaining the WMAP data. We then review the connection between VSL and theories of quantum gravity, showing how ``doubly special'' relativity has emerged as a VSL effective model of quantum space...

  11. Edge Modeling by Two Blur Parameters in Varying Contrasts.

    Science.gov (United States)

    Seo, Suyoung

    2018-06-01

    This paper presents a method of modeling edge profiles with two blur parameters, and estimating and predicting those edge parameters with varying brightness combinations and camera-to-object distances (COD). First, the validity of the edge model is proven mathematically. Then, it is proven experimentally with edges from a set of images captured for specifically designed target sheets and with edges from natural images. Estimation of the two blur parameters for each observed edge profile is performed with a brute-force method to find parameters that produce global minimum errors. Then, using the estimated blur parameters, actual blur parameters of edges with arbitrary brightness combinations are predicted using a surface interpolation method (i.e., kriging). The predicted surfaces show that the two blur parameters of the proposed edge model depend on both dark-side edge brightness and light-side edge brightness following a certain global trend. This is similar across varying CODs. The proposed edge model is compared with a one-blur parameter edge model using experiments of the root mean squared error for fitting the edge models to each observed edge profile. The comparison results suggest that the proposed edge model has superiority over the one-blur parameter edge model in most cases where edges have varying brightness combinations.

  12. Data Challenges

    CERN Multimedia

    McCubbin, N A

    Some two years ago we planned a series of Data Challenges starting at the end of 2001. At the time, that seemed to be comfortingly far in the future... Well, as the saying goes, doesn't time fly when you are having fun! ATLAS Computing is now deep in the throes of getting the first Data Challenge (DC0) up and running. One of the main aims of DC0 is to have a software 'release' in which we can generate full physics events, track all particles through the detector, simulate the detector response, reconstruct the event, and study it, with appropriate data storage en route. As all software is "always 95% ready" (!), we have been able to do most of this, more or less, for some time. But DC0 forces us to have everything working, together, at the same time: a reality check. DC0 should finish early next year, and it will be followed almost immediately afterwards by DC1 (DC0 was foreseen as the 'check' for DC1). DC1 will last into the middle of 2002, and has two major goals. The first is generation, simulation, and r...

  13. Challenging makerspaces

    DEFF Research Database (Denmark)

    Sandvik, Kjetil; Thestrup, Klaus

    This paper takes its departure in the EU-project MakEY - Makerspaces in the early years – enhancing digital literacy and creativity that is part of a H2020 RISE-program and is running January 2017 - June 2019. Here digital literacy and creative skills of young children between the age of 3......-8 will be developed through participation in creative activities in specially-designed spaces termed ‘makerspaces’. This paper discusses, develops and challenges this term in relation to Danish pedagogical traditions, to expanding makerspaces onto the internet and on how to combine narratives and construction....... The Danish part of the project will be undertaken by a small network of partners: DOKK1, a public library and open urban space in Aarhus, that is experimenting with different kind of makerspaces, spaces and encounters between people, The LEGO-LAB situated at Computer Science, Aarhus University, that has...

  14. New varying speed of light theories

    International Nuclear Information System (INIS)

    Magueijo, Joao

    2003-01-01

    We review recent work on the possibility of a varying speed of light (VSL). We start by discussing the physical meaning of a varying-c, dispelling the myth that the constancy of c is a matter of logical consistency. We then summarize the main VSL mechanisms proposed so far: hard breaking of Lorentz invariance; bimetric theories (where the speeds of gravity and light are not the same); locally Lorentz invariant VSL theories; theories exhibiting a colour-dependent speed of light; varying-c induced by extra dimensions (e.g. in the brane-world scenario); and field theories where VSL results from vacuum polarization or CPT violation. We show how VSL scenarios may solve the cosmological problems usually tackled by inflation, and also how they may produce a scale-invariant spectrum of Gaussian fluctuations, capable of explaining the WMAP data. We then review the connection between VSL and theories of quantum gravity, showing how 'doubly special' relativity has emerged as a VSL effective model of quantum space-time, with observational implications for ultra-high energy cosmic rays (UHECRs) and gamma ray bursts. Some recent work on the physics of 'black' holes and other compact objects in VSL theories is also described, highlighting phenomena associated with spatial (as opposed to temporal) variations in c. Finally, we describe the observational status of the theory. The evidence is currently slim-redshift dependence in the atomic fine structure, anomalies with UHECRs, and (to a much lesser extent) the acceleration of the universe and the WMAP data. The constraints (e.g. those arising from nucleosynthesis or geological bounds) are tight but not insurmountable. We conclude with the observational predictions of the theory and the prospects for its refutation or vindication

  15. Conceptual Modeling of Time-Varying Information

    DEFF Research Database (Denmark)

    Gregersen, Heidi; Jensen, Christian S.

    2004-01-01

    A wide range of database applications manage information that varies over time. Many of the underlying database schemas of these were designed using the Entity-Relationship (ER) model. In the research community as well as in industry, it is common knowledge that the temporal aspects of the mini......-world are important, but difficult to capture using the ER model. Several enhancements to the ER model have been proposed in an attempt to support the modeling of temporal aspects of information. Common to the existing temporally extended ER models, few or no specific requirements to the models were given...

  16. A time-varying magnetic flux concentrator

    International Nuclear Information System (INIS)

    Kibret, B; Premaratne, M; Lewis, P M; Thomson, R; Fitzgerald, P B

    2016-01-01

    It is known that diverse technological applications require the use of focused magnetic fields. This has driven the quest for controlling the magnetic field. Recently, the principles in transformation optics and metamaterials have allowed the realization of practical static magnetic flux concentrators. Extending such progress, here, we propose a time-varying magnetic flux concentrator cylindrical shell that uses electric conductors and ferromagnetic materials to guide magnetic flux to its center. Its performance is discussed based on finite-element simulation results. Our proposed design has potential applications in magnetic sensors, medical devices, wireless power transfer, and near-field wireless communications. (paper)

  17. Varying Readability of Science-Based Text in Elementary Readers: Challenges for Teachers

    Science.gov (United States)

    Gallagher, Tiffany L.; Fazio, Xavier; Gunning, Thomas G.

    2012-01-01

    This investigation compared readability formulae to publishers' identified reading levels in science-based elementary readers. Nine well-established readability indices were calculated and comparisons were made with the publishers' identified grade designations and between different genres of text. Results revealed considerable variance among the…

  18. Dinâmica da comunidade fitoplanctônica e variáveis físicas e químicas em tanques experimentais submetidos a diferentes adubações orgânicas Dynamics of the phytoplankton community and physical and chemical variables in experimental tanks with different organic manure

    Directory of Open Access Journals (Sweden)

    Claudemir Martins Soares

    2001-05-01

    Full Text Available Objetivando-se determinar a influência de diferentes adubos orgânicos na comunidade fitoplanctônica, realizou-se este experimento, com duração de 40 dias, em tanques de cimento amianto com capacidade para 1000l. Os tanques foram adubados com estercos de aves (EA, suínos (ES, bovinos (EB e coelhos (EC, em um delineamento inteiramente casualizado, com quatro tratamentos e cinco repetições. A primeira adubação foi de 50 g de esterco, sendo realizadas novas adubações com 25 g, em intervalos de sete dias. O plâncton foi coletado a cada três dias, filtrando-se 250 ml de água em rede de 20µm e fixados em 10mL de formalina 2%. A análise qualitativa e quantitativa foi realizada em microscópio óptico. Ao mesmo tempo, foram monitoradas algumas variáveis físicas e químicas. A densidade média mais elevada do fitoplâncton foi observada com o uso de EA no 40º dia (26.842 org./l, seguido de ES (17.164 org./L, no 22º dia, EC (8.880 org./L, no 28º dia e EB (5.564 org./l, no 22º dia. Houve predominância dos gêneros Scenedesmus, Cyclotella e Acanthosphaera. Os valores de pH e condutividade elétrica oscilaram conforme ocorriam alterações nas densidades do fitoplâncton. O uso de EA levou a maiores valores destes parâmetros na maioria das coletas. Conclui-se que os diferentes tratamentos exerceram influência na densidade dos grupos fitoplanctônicos; entretanto estercos de aves levaram à maior densidade de algas, seguidos por esterco de suínos, coelhos e bovinosThe influence of different types of organic manure in the phytoplankton community is provided. Experiment was undertaken during 40 days in 1000L asbestos tanks. Tanks were fertilized with poultry (PO, pig (PI, cattle (CA and rabbit (RA manure, in a randomized design, with four treatments and five replications. First fertilization consisted of 50 g of manure, with 25 g fertilizations at seven-day intervals. Plankton was collected every three days by filtering 250 mL of water

  19. Progress report on the varying temperature experiment

    International Nuclear Information System (INIS)

    Qualls, A.L.; Hurst, M.T.; Raby, D.G.

    1997-01-01

    A capsule has been designed that permits four specimen sets to be irradiated in an RB* location in the High Flux Isotope reactor (HFIR) with distinct temperature histories. During the reporting period critical component prototyping was completed. The results have lead to some design and operational changes from that previously reported. The primary design changes are (1) compression seals in the specimen holes of the beryllium holders, and (2) oxide-dispersion strengthened aluminum alloy (DISPAL) specimen sleeves in all holders. Details of the capsule design are presented in the previous issue of this publication. Four, axially displaced temperature zones are independently controlled. Holder temperatures are monitored by thermocouples and controlled by a combination of adjustable temperature control gas mixtures and auxiliary heaters. The high temperature holders are located in the center of the experimental region, which is centered on the reactor mid-plane, and the low temperature holders are located at the ends of the experimental region

  20. Progress report on the varying temperature experiment

    Energy Technology Data Exchange (ETDEWEB)

    Qualls, A.L.; Hurst, M.T.; Raby, D.G. [Oak Ridge National Lab., TN (United States)] [and others

    1997-08-01

    A capsule has been designed that permits four specimen sets to be irradiated in an RB* location in the High Flux Isotope reactor (HFIR) with distinct temperature histories. During the reporting period critical component prototyping was completed. The results have lead to some design and operational changes from that previously reported. The primary design changes are (1) compression seals in the specimen holes of the beryllium holders, and (2) oxide-dispersion strengthened aluminum alloy (DISPAL) specimen sleeves in all holders. Details of the capsule design are presented in the previous issue of this publication. Four, axially displaced temperature zones are independently controlled. Holder temperatures are monitored by thermocouples and controlled by a combination of adjustable temperature control gas mixtures and auxiliary heaters. The high temperature holders are located in the center of the experimental region, which is centered on the reactor mid-plane, and the low temperature holders are located at the ends of the experimental region.

  1. Electrothermally Actuated Microbeams With Varying Stiffness

    KAUST Repository

    Tella, Sherif Adekunle

    2017-11-03

    We present axially loaded clamped-guided microbeams that can be used as resonators and actuators of variable stiffness, actuation, and anchor conditions. The applied axial load is implemented by U-shaped electrothermal actuators stacked at one of the beams edges. These can be configured and wired in various ways, which serve as mechanical stiffness elements that control the operating resonance frequency of the structures and their static displacement. The experimental results have shown considerable increase in the resonance frequency and mid-point deflection of the microbeam upon changing the end conditions of the beam. These results can be promising for applications requiring large deflection and high frequency tunability, such as filters, memory devices, and switches. The experimental results are compared to multi-physics finite-element simulations showing good agreement among them.

  2. Time-varying output performances of piezoelectric vibration energy harvesting under nonstationary random vibrations

    Science.gov (United States)

    Yoon, Heonjun; Kim, Miso; Park, Choon-Su; Youn, Byeng D.

    2018-01-01

    Piezoelectric vibration energy harvesting (PVEH) has received much attention as a potential solution that could ultimately realize self-powered wireless sensor networks. Since most ambient vibrations in nature are inherently random and nonstationary, the output performances of PVEH devices also randomly change with time. However, little attention has been paid to investigating the randomly time-varying electroelastic behaviors of PVEH systems both analytically and experimentally. The objective of this study is thus to make a step forward towards a deep understanding of the time-varying performances of PVEH devices under nonstationary random vibrations. Two typical cases of nonstationary random vibration signals are considered: (1) randomly-varying amplitude (amplitude modulation; AM) and (2) randomly-varying amplitude with randomly-varying instantaneous frequency (amplitude and frequency modulation; AM-FM). In both cases, this study pursues well-balanced correlations of analytical predictions and experimental observations to deduce the relationships between the time-varying output performances of the PVEH device and two primary input parameters, such as a central frequency and an external electrical resistance. We introduce three correlation metrics to quantitatively compare analytical prediction and experimental observation, including the normalized root mean square error, the correlation coefficient, and the weighted integrated factor. Analytical predictions are in an excellent agreement with experimental observations both mechanically and electrically. This study provides insightful guidelines for designing PVEH devices to reliably generate electric power under nonstationary random vibrations.

  3. Varying prior information in Bayesian inversion

    International Nuclear Information System (INIS)

    Walker, Matthew; Curtis, Andrew

    2014-01-01

    Bayes' rule is used to combine likelihood and prior probability distributions. The former represents knowledge derived from new data, the latter represents pre-existing knowledge; the Bayesian combination is the so-called posterior distribution, representing the resultant new state of knowledge. While varying the likelihood due to differing data observations is common, there are also situations where the prior distribution must be changed or replaced repeatedly. For example, in mixture density neural network (MDN) inversion, using current methods the neural network employed for inversion needs to be retrained every time prior information changes. We develop a method of prior replacement to vary the prior without re-training the network. Thus the efficiency of MDN inversions can be increased, typically by orders of magnitude when applied to geophysical problems. We demonstrate this for the inversion of seismic attributes in a synthetic subsurface geological reservoir model. We also present results which suggest that prior replacement can be used to control the statistical properties (such as variance) of the final estimate of the posterior in more general (e.g., Monte Carlo based) inverse problem solutions. (paper)

  4. Brown Dwarf Variability: What's Varying and Why?

    Science.gov (United States)

    Marley, Mark Scott

    2014-01-01

    Surveys by ground based telescopes, HST, and Spitzer have revealed that brown dwarfs of most spectral classes exhibit variability. The spectral and temporal signatures of the variability are complex and apparently defy simplistic classification which complicates efforts to model the changes. Important questions include understanding if clearings are forming in an otherwise uniform cloud deck or if thermal perturbations, perhaps associated with breaking gravity waves, are responsible. If clouds are responsible how long does it take for the atmospheric thermal profile to relax from a hot cloudy to a cooler cloudless state? If thermal perturbations are responsible then what atmospheric layers are varying? How do the observed variability timescales compare to atmospheric radiative, chemical, and dynamical timescales? I will address such questions by presenting modeling results for time-varying partly cloudy atmospheres and explore the importance of various atmospheric processes over the relevant timescales for brown dwarfs of a range of effective temperatures. Regardless of the origin of the observed variability, the complexity seen in the atmospheres of the field dwarfs hints at the variability that we may encounter in the next few years in directly imaged young Jupiters. Thus understanding the nature of variability in the field dwarfs, including sensitivity to gravity and metallicity, is of particular importance for exoplanet characterization.

  5. Glomar challenger

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, J P

    1969-01-01

    The Glomar Challenger has a length of 400 ft, a 65-ft beam, and a depth of 27 ft 6-in. She has a draft of 20 ft with a gross displacement of 10,500 long tons. The principal specifications of the vessel are tabulated. To achieve dynamic positioning, 4 fixed thrusters and the vessel's 2 propulsion screws are utilized. The ''fix'' is obtained by placing a sonar beacon, with self contained batteries, on the ocean floor at a selected site. The vessel is provided with 4 hydrophones installed in the hull at the 4 corners of a square. The sonar beacon radiates sound waves at a fixed pulse rate. If the vessel is directly over the beacon, the sound waves will arrive at all hydrophones simultaneously. A difference in time of arrival indicates the vessel is off location. The sound signals received by the hydrophones are fed into a computer. They are changed into coordinate information, which serves as the primary function of determining corrective action by the vessel's propulsion and thruster system. The computer feeds back information into a control system, which enables the propulsion and thrusters to automatically respond, in order to keep the vessel on the predetermined location. The major drilling components are listed. The deep-sea drilling project is described. A summary of the first leg is given in tabular form.

  6. Scrapheap Challenge

    CERN Document Server

    2004-01-01

    Three British guys at CERN recently took a break from work to try their hand at Scrapheap Challenge. Shown on Channel 4 in the UK, it is a show where two teams must construct a machine for a specific task using only the junk they can scavenge from the scrap yard around them. And they have just 10 hours to build their contraption before it is put to the test. The first round, aired 19 September, pitted a team of three women, from the British Army's Royal Electrical and Mechanical Engineers, against the CERN guys - the Up 'n Atoms: Ali Day, David McFarlane and James Ridewood. Each team, with the help of an appointed expert, had the task of making a giant, 3-metre self-propelled "bowling ball", to roll down a 50 metre bowling alley at skittles 4 metres high. The Up 'n Atoms' contraption featured a small car with a huge wheel on its back. Once up to speed, slamming on the brakes caused the wheel to roll over and take the car with it. On their very last run they managed to take out seven pins. Luckily, though, ...

  7. The Terawatt Challenge

    Science.gov (United States)

    Haegel, Nancy

    In response to concerns about accelerating climate change, the world is uniting to both envision and enable a global energy system that supports a sustainable environment and broad economic prosperity. Growth in the technology and the deployment of renewable energy has been dramatic. Evidence can be seen in the growth of photovoltaics (PV) and wind as contributors to worldwide electricity production over the last decade. PV and wind provided 1.2% and 3.7% of global electricity production in 2015, compared to 0.1% and 1.3% respectively in 2005. These numbers indicate both the rapid increase in the rate of deployment, as well as the remaining work to be done to extend this trend to transform a massive energy system and provide a significant fraction of the world's future energy demand with renewable energy. Based on recent trends, it is highly likely that global cumulative PV installation will reach terawatt scale in the next few decades. The challenges, as well as the resulting impact, vary greatly depending on whether we envision 1 TW ( 15% of 2015 global electricity capacity), 3 TW ( 50% of 2015 global electricity capacity) or 10 TW, a level that could drive electrification of transportation and industrial sectors and production of solar fuels. This presentation will draw upon the work of the 2016 GA-SERI (Global Alliance of Solar Energy Research Institutes) Terawatt Workshop to assess the feasibility and summarize the challenges for PV as a primary energy source. These challenges include the continuing demand for improved efficiency and reliability, the required magnitude of capital expenditure, the need for a sustainable industry (both financially and environmentally), as well as needs for grid modernization and consistent policies that support global climate goals. Physicists can play important roles in addressing this full range of challenges, from materials science to public policy, as well as in education of the public and its future leaders.

  8. Time-Varying Periodicity in Intraday Volatility

    DEFF Research Database (Denmark)

    Andersen, Torben Gustav; Thyrsgaard, Martin; Todorov, Viktor

    We develop a nonparametric test for deciding whether return volatility exhibits time-varying intraday periodicity using a long time-series of high-frequency data. Our null hypothesis, commonly adopted in work on volatility modeling, is that volatility follows a stationary process combined...... with a constant time-of-day periodic component. We first construct time-of-day volatility estimates and studentize the high-frequency returns with these periodic components. If the intraday volatility periodicity is invariant over time, then the distribution of the studentized returns should be identical across...... with estimating volatility moments through their sample counterparts. Critical values are computed via easy-to-implement simulation. In an empirical application to S&P 500 index returns, we find strong evidence for variation in the intraday volatility pattern driven in part by the current level of volatility...

  9. Flexible time-varying filter banks

    Science.gov (United States)

    Tuncer, Temel E.; Nguyen, Truong Q.

    1993-09-01

    Linear phase maximally flat FIR Butterworth filter approximations are discussed and a new filter design method is introduced. This variable cutoff filter design method uses the cosine modulated versions of a prototype filter. The design procedure is simple and different variants of this procedure can be used to obtain close to optimum linear phase filters. Using this method, flexible time-varying filter banks with good reconstruction error are introduced. These types of oversampled filter banks have small magnitude error which can be easily controlled by the appropriate choice of modulation frequency. This error can be further decreased by magnitude equalization without increasing the computational complexity considerably. Two dimensional design examples are also given.

  10. Behavior of varying-alpha cosmologies

    International Nuclear Information System (INIS)

    Barrow, John D.; Sandvik, Haavard Bunes; Magueijo, Joao

    2002-01-01

    We determine the behavior of a time-varying fine structure 'constant' α(t) during the early and late phases of universes dominated by the kinetic energy of changing α(t), radiation, dust, curvature, and lambda, respectively. We show that after leaving an initial vacuum-dominated phase during which α increases, α remains constant in universes such as our own during the radiation era, and then increases slowly, proportional to a logarithm of cosmic time, during the dust era. If the universe becomes dominated by a negative curvature or a positive cosmological constant then α tends rapidly to a constant value. The effect of an early period of de Sitter or power-law inflation is to drive α to a constant value. Various cosmological consequences of these results are discussed with reference to recent observational studies of the value of α from quasar absorption spectra and to the existence of life in expanding universes

  11. Emergence of epidemics in rapidly varying networks

    International Nuclear Information System (INIS)

    Kohar, Vivek; Sinha, Sudeshna

    2013-01-01

    We describe a simple model mimicking disease spreading on a network with dynamically varying connections, and investigate the dynamical consequences of switching links in the network. Our central observation is that the disease cycles get more synchronized, indicating the onset of epidemics, as the underlying network changes more rapidly. This behavior is found for periodically switched links, as well as links that switch randomly in time. We find that the influence of changing links is more pronounced in networks where the nodes have lower degree, and the disease cycle has a longer infective stage. Further, when the switching of links is periodic we observe finer dynamical features, such as beating patterns in the emergent oscillations and resonant enhancement of synchronization, arising from the interplay between the time-scales of the connectivity changes and that of the epidemic outbreaks

  12. Comparison of commercial and experimental porcine circovirus type 2 (PCV2) vaccines using a triple challenge with PCV2, porcine reproductive and respiratory syndrome virus (PRRSV), and porcine parvovirus (PPV).

    Science.gov (United States)

    Shen, H G; Beach, N M; Huang, Y W; Halbur, P G; Meng, X J; Opriessnig, T

    2010-08-23

    The efficacies of commercial porcine circovirus type 2 (PCV2) vaccines and a live PCV1-2a chimeric vaccine were compared in conventional, PCV2-positive piglets using a PCV2-porcine reproductive and respiratory syndrome virus (PRRSV)-porcine parvovirus (PPV) coinfection challenge model. Seventy-three, 2-week-old pigs were randomized into seven groups including five vaccinated and two control groups. Pigs in the vaccinated groups were vaccinated at 3 weeks (one dose) or at 3 and 6 weeks (two dose) of age. All vaccine regimens tested were effective in reducing naturally occurring PCV2 viremia at 16 weeks of age and after PCV2 challenge, demonstrating the capability of the products to induce a lasting protective immunity despite the presence of PCV2 viremia at the time of vaccination. Copyright 2010 Elsevier Ltd. All rights reserved.

  13. Regulatory challenges

    International Nuclear Information System (INIS)

    Austvik, Ole Gunnar

    2003-01-01

    The problem for policy makers wanting to liberalize natural gas markets is that its concentrated structure may also be the socially most efficient one. Because of scale economies, more firms operating in the market may incur higher transportation costs unless the market grows sufficiently in each geographic segment. This argument goes for product extension through vertical (or horizontal) integration and the exploitation of economies of scope as well. Thus, the challenge for governments is to intervene in a way that preserves a market structure that has the potential to minimize cost, and at the same lime change its behavior in order to avoid possible lax cost control and exploitation of market power. The existence of scope advantages indicates that liberalization of the market should open for the possibility to bundle services in competition with provision of unbundled services. If operations are unbundled and there exist economies of scope, the gain from increased competition should be weighed against the losses of less efficient operations of each firm. Thus, with the growth in the European market, gradually more arguments support the idea of unbundling. The significant scale economy in trunk pipelines, sunk investments and capital immobility, possible economies of scope in vertical integration and companies' bundling of services influences vertical and horizontal ownership relations and contractual terms in the European gas market. In specific segments of the markets, these relationships may promote efficient investments and pricing without public interference, but the strong concentration of market power indicates that this is rather the exception than the rule. In order to design an efficient and welfare maximizing way of regulating the market one needs a closer identification of the actual goal of the regulation. Microeconomic theory is often used for this purpose. The author discusses the alternatives of laissez-faire, nationalization or regulation for the

  14. Superheated emulsions in neutron spectrometry by varying ambient pressure

    International Nuclear Information System (INIS)

    Das, Mala; Sawamura, Teruko

    2005-01-01

    The principle of present work lies on the dependence of the threshold neutron energy on the dimensionless quantity ''degree of metastability (ss)'' of superheated liquids. The response of the superheated emulsions consists of the drops of superheated liquid (C 2 Cl 2 F 4 , b.p. 3.77 deg. C) has been measured at different 'ss' by varying ambient pressure at different temperatures, in the presence of neutrons generated in Pb by a (γ,n) reaction from 45 MeV electron LINAC of Hokkaido University. To unfold the neutron energy spectrum, a relationship has been developed between the 'ss' of superheated liquids and the threshold neutron energy. The spectrum at the detector position has been calculated by the MCNP code and a comparison has been made with the experimental spectrum. The utilisation of 'ss' is more flexible as this relation can be applied to both positive and negative ambient pressures as well as at different ambient temperatures

  15. Cold fission description with constant and varying mass asymmetries

    International Nuclear Information System (INIS)

    Duarte, S.B.; Rodriguez, O.; Tavares, O.A.P.; Goncalves, M.; Garcia, F.; Guzman, F.

    1998-01-01

    Different description for varying the mass asymmetry in the fragmentation process are used to calculate the cold fission barrier penetrability. The relevance of the appropriate choice for both the description of the pre-scission phase and inertia coefficient to unify alpha decay, cluster radioactivity, and spontaneous cold fission processes in the same theoretical framework is explicitly shown. We calculate the half-life of all possible partition modes of nuclei of A > 200 following the most recent Mass Table by Audi and Wapstra. It is shown that if one uses the description in which the mass asymmetry is maintained constant during the fragmentation process, the experimental half-life-values and mass yield of 234 U cold fission are satisfactorily reproduced. (author)

  16. A Diagnostic System for Speed-Varying Motor Rotary Faults

    Directory of Open Access Journals (Sweden)

    Chwan-Lu Tseng

    2014-01-01

    Full Text Available This study proposed an intelligent rotary fault diagnostic system for motors. A sensorless rotational speed detection method and an improved dynamic structural neural network are used. Moreover, to increase the convergence speed of training, a terminal attractor method and a hybrid discriminant analysis are also adopted. The proposed method can be employed to detect the rotary frequencies of motors with varying speeds and can enhance the discrimination of motor faults. To conduct the experiments, this study used wireless sensor nodes to transmit vibration data and employed MATLAB to write codes for functional modules, including the signal processing, sensorless rotational speed estimation, neural network, and stochastic process control chart. Additionally, Visual Basic software was used to create an integrated human-machine interface. The experimental results regarding the test of equipment faults indicated that the proposed novel diagnostic system can effectively estimate rotational speeds and provide superior ability of motor fault discrimination with fast training convergence.

  17. Consumer responses to time varying prices for electricity

    International Nuclear Information System (INIS)

    Thorsnes, Paul; Williams, John; Lawson, Rob

    2012-01-01

    We report new experimental evidence of the household response to weekday differentials in peak and off-peak electricity prices. The data come from Auckland, New Zealand, where peak residential electricity consumption occurs in winter for heating. Peak/off-peak price differentials ranged over four randomly selected groups from 1.0 to 3.5. On average, there was no response except in winter. In winter, participant households reduced electricity consumption by at least 10%, took advantage of lower off-peak prices but did not respond to the peak price differentials. Response varied with house and household size, time spent away from home, and whether water was heated with electricity. - Highlights: ► Seasonal effects in winter. ► High conservation effect from information. ► Higher peak prices no effect on peak use. ► Low off-peak prices encourage less conservation off-peak.

  18. Reduction of porcine circovirus type 2 (PCV2 viremia by a reformulated inactivated chimeric PCV1-2 vaccine-induced humoral and cellular immunity after experimental PCV2 challenge

    Directory of Open Access Journals (Sweden)

    Seo Hwi

    2012-10-01

    Full Text Available Abstract Background The objective of the present study was to elucidate the humoral and cellular immune response mechanisms by which a reformulated inactivated chimeric PCV1-2 vaccine reduces the PCV2 viremia. Forty PCV2 seronegative 3-week-old pigs were randomly divided into the following four groups: vaccinated challenged (T01, vaccinated non-challenged (T02, non-vaccinated challenged (T03, and non-vaccinated non-challenged (T04 animals. The pigs in groups T01 and T02 were immunized with a reformulated inactivated chimeric PCV1-2 vaccine (Fostera™ PCV; Pfizer Animal Health administered as a 2.0 ml dose at 21 days of age. At 35 days of age (0 days post-challenge, the pigs in groups T01 and T03 were inoculated intranasally with 2 ml each of PCV2b. Results A reduction of PCV2 viremia coincided with the appearance of both PCV2-specific neutralizing antibodies (NA and interferon-γ-secreting cells (IFN-γ-SCs in the vaccinated animals. However, the presence of anti-PCV2 IgG antibodies did not correlate with the reduction of PCV2 viremia. Lymphocyte subset analysis indicated that the numbers of CD3+ and CD4+ cells increased in vaccinated animals but the numbers of CD4+ cells decreased transiently in non-vaccinated animals. The observation of a delayed type hypersensitivity response in only the vaccinated animals also supports a CD4+ cell-associated protective cellular immune response induced by the reformulated inactivated chimeric PCV1-2 vaccine. Conclusions The induction of PCV2-specific NA and IFN-γ-SCs, and CD4+ cells by the reformulated inactivated chimeric PCV1-2 vaccine is the important protective immune response leading to reduction of the PCV2 viremia and control of the PCV2 infection. To our knowledge this is the first demonstration of protective humoral and cellular immunity induced by the reformulated inactivated chimeric PCV1-2 vaccine and its effect on reduction of PCV2 viremia by vaccination.

  19. Changing times, similar challenges.

    Science.gov (United States)

    Baillie, Jonathan

    2013-11-01

    With IHEEM celebrating its 70th Anniversary this month, HEJ editor, Jonathan Baillie, recently met the Institute's oldest surviving Past-President, Lawrence Turner OBE, who, having in 1964 established a small engineering business producing some of the NHS's earliest nurse call systems from the basement of his three-storey West Midlands home, has since seen the company, Static Systems Group, grow to become one of the U.K. market-leaders in its field. The Institute's President from 1979-1981, he looked back, during a fascinating two-hour discussion, at his time in the role, talked through some of the key technological and other changes he has seen in the past five decades, reflected on an interesting and varied career, and considered some of the very different current-day challenges that today's IHEEM President, and the Institute as a whole, face.

  20. Hydroquinone–pyrrole dyads with varied linkers

    Directory of Open Access Journals (Sweden)

    Hao Huang

    2016-01-01

    Full Text Available A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV–vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the trans-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO–LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices.

  1. Modelling tourists arrival using time varying parameter

    Science.gov (United States)

    Suciptawati, P.; Sukarsa, K. G.; Kencana, Eka N.

    2017-06-01

    The importance of tourism and its related sectors to support economic development and poverty reduction in many countries increase researchers’ attentions to study and model tourists’ arrival. This work is aimed to demonstrate time varying parameter (TVP) technique to model the arrival of Korean’s tourists to Bali. The number of Korean tourists whom visiting Bali for period January 2010 to December 2015 were used to model the number of Korean’s tourists to Bali (KOR) as dependent variable. The predictors are the exchange rate of Won to IDR (WON), the inflation rate in Korea (INFKR), and the inflation rate in Indonesia (INFID). Observing tourists visit to Bali tend to fluctuate by their nationality, then the model was built by applying TVP and its parameters were approximated using Kalman Filter algorithm. The results showed all of predictor variables (WON, INFKR, INFID) significantly affect KOR. For in-sample and out-of-sample forecast with ARIMA’s forecasted values for the predictors, TVP model gave mean absolute percentage error (MAPE) as much as 11.24 percent and 12.86 percent, respectively.

  2. Microsatellites in varied arenas of research

    Directory of Open Access Journals (Sweden)

    K S Remya

    2010-01-01

    Full Text Available Microsatellites known as simple-sequence repeats (SSRs or short-tandem repeats (STRs, represent specific sequences of DNA consisting of tandemly repeated units of one to six nucleotides. The repetitive nature of microsatellites makes them particularly prone to grow or shrink in length and these changes can have both good and bad consequences for the organisms that possess them. They are responsible for various neurological diseases and hence the same cause is now utilized for the early detection of various diseases, such as, Schizophrenia and Bipolar Disorder, Congenital generalized Hypertrichosis, Asthma, and Bronchial Hyperresponsiveness. These agents are widely used for forensic identification and relatedness testing, and are predominant genetic markers in this area of application. The application of microsatellites is an extending web and covers the varied scenarios of science, such as, conservation biology, plant genetics, and population studies. At present, researches are progressing round the globe to extend the use of these genetic repeaters to unmask the hidden genetic secrets behind the creation of the world.

  3. Varying coefficients model with measurement error.

    Science.gov (United States)

    Li, Liang; Greene, Tom

    2008-06-01

    We propose a semiparametric partially varying coefficient model to study the relationship between serum creatinine concentration and the glomerular filtration rate (GFR) among kidney donors and patients with chronic kidney disease. A regression model is used to relate serum creatinine to GFR and demographic factors in which coefficient of GFR is expressed as a function of age to allow its effect to be age dependent. GFR measurements obtained from the clearance of a radioactively labeled isotope are assumed to be a surrogate for the true GFR, with the relationship between measured and true GFR expressed using an additive error model. We use locally corrected score equations to estimate parameters and coefficient functions, and propose an expected generalized cross-validation (EGCV) method to select the kernel bandwidth. The performance of the proposed methods, which avoid distributional assumptions on the true GFR and residuals, is investigated by simulation. Accounting for measurement error using the proposed model reduced apparent inconsistencies in the relationship between serum creatinine and GFR among different clinical data sets derived from kidney donor and chronic kidney disease source populations.

  4. Stratospheric Impact of Varying Sea Surface Temperatures

    Science.gov (United States)

    Newman, Paul A.; Nash, Eric R.; Nielsen, Jon E.; Waugh, Darryn; Pawson, Steven

    2004-01-01

    The Finite-Volume General Circulation Model (FVGCM) has been run in 50 year simulations with the: 1) 1949-1999 Hadley Centre sea surface temperatures (SST), and 2) a fixed annual cycle of SSTs. In this presentation we first show that the 1949-1999 FVGCM simulation produces a very credible stratosphere in comparison to an NCEP/NCAR reanalysis climatology. In particular, the northern hemisphere has numerous major and minor stratospheric warming, while the southern hemisphere has only a few over the 50-year simulation. During the northern hemisphere winter, temperatures are both warmer in the lower stratosphere and the polar vortex is weaker than is found in the mid-winter southern hemisphere. Mean temperature differences in the lower stratosphere are shown to be small (less than 2 K), and planetary wave forcing is found to be very consistent with the climatology. We then will show the differences between our varying SST simulation and the fixed SST simulation in both the dynamics and in two parameterized trace gases (ozone and methane). In general, differences are found to be small, with subtle changes in planetary wave forcing that lead to reduced temperatures in the SH and increased temperatures in the NH.

  5. TIME-VARYING DYNAMICAL STAR FORMATION RATE

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eve J.; Chang, Philip; Murray, Norman, E-mail: evelee@berkeley.edu [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, University of Toronto, Toronto, ON M5S 3H8 (Canada)

    2015-02-10

    We present numerical evidence of dynamic star formation in which the accreted stellar mass grows superlinearly with time, roughly as t {sup 2}. We perform simulations of star formation in self-gravitating hydrodynamic and magnetohydrodynamic turbulence that is continuously driven. By turning the self-gravity of the gas in the simulations on or off, we demonstrate that self-gravity is the dominant physical effect setting the mass accretion rate at early times before feedback effects take over, contrary to theories of turbulence-regulated star formation. We find that gravitational collapse steepens the density profile around stars, generating the power-law tail on what is otherwise a lognormal density probability distribution function. Furthermore, we find turbulent velocity profiles to flatten inside collapsing regions, altering the size-line width relation. This local flattening reflects enhancements of turbulent velocity on small scales, as verified by changes to the velocity power spectra. Our results indicate that gas self-gravity dynamically alters both density and velocity structures in clouds, giving rise to a time-varying star formation rate. We find that a substantial fraction of the gas that forms stars arrives via low-density flows, as opposed to accreting through high-density filaments.

  6. Debating Life on Mars: The Knowledge Integration Environment (KIE) in Varied School Settings.

    Science.gov (United States)

    Shear, Linda

    Technology-enabled learning environments are beginning to come of age. Tools and frameworks are now available that have been shown to improve learning and are being deployed more widely in varied school settings. Teachers are now faced with the formidable challenge of integrating these promising new environments with the everyday context in which…

  7. Smoothly varying in-plane stiffness heterogeneity evaluated under uniaxial tensile stress

    Science.gov (United States)

    J.M. Considine; F. Pierron; K.T. Turner; P. Lava; X. Tang

    2017-01-01

    Identification of spatially varying stiffness is a challenging, but important, research topic in the mechanics of materials and can provide the necessary information for material suitability, damage, and process control, especially for high‐value applications. One homogeneous and 3 heterogeneous virtual field method (VFM) formulations were used to create a methodology...

  8. Flow in curved ducts of varying cross-section

    Science.gov (United States)

    Sotiropoulos, F.; Patel, V. C.

    1992-07-01

    Two numerical methods for solving the incompressible Navier-Stokes equations are compared with each other by applying them to calculate laminar and turbulent flows through curved ducts of regular cross-section. Detailed comparisons, between the computed solutions and experimental data, are carried out in order to validate the two methods and to identify their relative merits and disadvantages. Based on the conclusions of this comparative study a numerical method is developed for simulating viscous flows through curved ducts of varying cross-sections. The proposed method is capable of simulating the near-wall turbulence using fine computational meshes across the sublayer in conjunction with a two-layer k-epsilon model. Numerical solutions are obtained for: (1) a straight transition duct geometry, and (2) a hydroturbine draft-tube configuration at model scale Reynolds number for various inlet swirl intensities. The report also provides a detailed literature survey that summarizes all the experimental and computational work in the area of duct flows.

  9. Informing the Historical Record of Experimental Nonhuman Primate Infections with Ebola Virus: Genomic Characterization of USAMRIID Ebola Virus/H.sapiens-tc/COD/1995/Kikwit-9510621 Challenge Stock "R4368" and Its Replacement "R4415".

    Directory of Open Access Journals (Sweden)

    Jeffrey R Kugelman

    Full Text Available The creation of licensed medical countermeasures against Select Agents such as Ebola virus (EBOV is critically dependent on the use of standardized reagents, assays, and animal models. We performed full genome reconstruction, population genomics, contaminant analysis, and characterization of the glycoprotein gene editing site of historical United States Army Medical Research Institute of Infectious Diseases (USAMRIID nonhuman-primate challenge stock Ebola virus Kikwit "R4368" and its 2014 replacement "R4415." We also provide characterization of the master stock used to create "R4415." The obtained data are essential to understanding the quality of the seed stock reagents used in pivotal animal studies that have been used to inform medical countermeasure development. Furthermore, these data might add to the understanding of the influence of EBOV variant populations on pathogenesis and disease outcome and inform attempts to avoid the evolution of EBOV escape mutants in response to current therapeutics. Finally, as the primary challenge stocks have changed over time, these data will provide a baseline for understanding and correlating past and future animal study results.

  10. Experimental infection of cliff swallows (Petrochelidon pyrrhonota) with varying doses of West Nile virus

    Science.gov (United States)

    Oesterle, P.T.; Nemeth, N.M.; VanDalen, Kaci K.; Sullivan, H.; Bentler, K.T.; Young, G.R.; McLean, R.G.; Clark, L.; Smeraski, C.; Hall, Jeffrey S.

    2009-01-01

    Cliff swallows (Petrochelidon pyrrhonota) were inoculated with differing doses of West Nile virus (WNV) to evaluate their potential role as reservoir hosts in nature. Swallows often nest in large colonies in habitats and months associated with high mosquito abundance and early WNV transmission in North America. Additionally, cliff swallow diet consists of insects, including mosquitoes, leading to an additional potential route of WNV infection. The average peak viremia titer among infected cliff swallows was 106.3 plaque-forming units (PFU)/mL serum and the reservoir competence index was 0.34. There was no correlation between dose and probability of becoming infected or viremia peak and duration. Oral shedding was detected from 2 to 14 days post-inoculation with an average peak titer of 1044 PFU/swab. These results suggest that cliff swallows are competent reservoir hosts of WNV and therefore, they may play a role in early seasonal amplification and maintenance of WNV. Copyright ?? 2009 by The American Society of Tropical Medicine and Hygiene.

  11. ESTIMATION OF CONSTANT AND TIME-VARYING DYNAMIC PARAMETERS OF HIV INFECTION IN A NONLINEAR DIFFERENTIAL EQUATION MODEL.

    Science.gov (United States)

    Liang, Hua; Miao, Hongyu; Wu, Hulin

    2010-03-01

    Modeling viral dynamics in HIV/AIDS studies has resulted in deep understanding of pathogenesis of HIV infection from which novel antiviral treatment guidance and strategies have been derived. Viral dynamics models based on nonlinear differential equations have been proposed and well developed over the past few decades. However, it is quite challenging to use experimental or clinical data to estimate the unknown parameters (both constant and time-varying parameters) in complex nonlinear differential equation models. Therefore, investigators usually fix some parameter values, from the literature or by experience, to obtain only parameter estimates of interest from clinical or experimental data. However, when such prior information is not available, it is desirable to determine all the parameter estimates from data. In this paper, we intend to combine the newly developed approaches, a multi-stage smoothing-based (MSSB) method and the spline-enhanced nonlinear least squares (SNLS) approach, to estimate all HIV viral dynamic parameters in a nonlinear differential equation model. In particular, to the best of our knowledge, this is the first attempt to propose a comparatively thorough procedure, accounting for both efficiency and accuracy, to rigorously estimate all key kinetic parameters in a nonlinear differential equation model of HIV dynamics from clinical data. These parameters include the proliferation rate and death rate of uninfected HIV-targeted cells, the average number of virions produced by an infected cell, and the infection rate which is related to the antiviral treatment effect and is time-varying. To validate the estimation methods, we verified the identifiability of the HIV viral dynamic model and performed simulation studies. We applied the proposed techniques to estimate the key HIV viral dynamic parameters for two individual AIDS patients treated with antiretroviral therapies. We demonstrate that HIV viral dynamics can be well characterized and

  12. Experimental and Field Results Regarding Immunity Induced by a Recombinant Turkey Herpesvirus H5 Vector Vaccine Against H5N1 and Other H5 Highly Pathogenic Avian Influenza Virus Challenges.

    Science.gov (United States)

    Gardin, Yannick; Palya, Vilmos; Dorsey, Kristi Moore; El-Attrache, John; Bonfante, Francesco; Wit, Sjaak de; Kapczynski, Darrell; Kilany, Walid Hamdy; Rauw, Fabienne; Steensels, Mieke; Soejoedono, Retno D

    2016-05-01

    Vaccination against H5N1 highly pathogenic avian influenza (AI) virus (HPAIV) is one of the possible complementary means available for affected countries to control AI when the disease has become, or with a high risk of becoming, endemic. Efficacy of the vaccination against AI relies essentially, but not exclusively, on the capacity of the vaccine to induce immunity against the targeted virus (which is prone to undergo antigenic variations), as well as its capacity to overcome interference with maternal immunity transmitted by immunized breeding hens to their progeny. This property of the vaccine is a prerequisite for its administration at the hatchery, which assures higher and more reliable vaccine coverage of the populations than vaccination at the farm. A recombinant vector vaccine (Vectormune® AI), based on turkey herpesvirus expressing the hemagglutinin gene of an H5N1 HPAIV as an insert, has been used in several experiments conducted in different research laboratories, as well as in controlled field trials. The results have demonstrated a high degree of homologous and cross protection against different genetic clades of the H5N1 HPAIV. Furthermore, vaccine-induced immunity was not impaired by the presence of passive immunity, but on the contrary, cumulated with it for improved early protection. The demonstrated levels of protection against the different challenge viruses exhibited variations in terms of postchallenge mortality, as well as challenge virus shedding. The data presented here highlight the advantages of this vaccine as a useful and reliable tool to complement biosecurity and sanitary policies for better controlling the disease due to HPAIV of H5 subtypes, when the vaccination is applied as a control measure.

  13. Identification of time-varying nonlinear systems using differential evolution algorithm

    DEFF Research Database (Denmark)

    Perisic, Nevena; Green, Peter L; Worden, Keith

    2013-01-01

    (DE) algorithm for the identification of time-varying systems. DE is an evolutionary optimisation method developed to perform direct search in a continuous space without requiring any derivative estimation. DE is modified so that the objective function changes with time to account for the continuing......, thus identification of time-varying systems with nonlinearities can be a very challenging task. In order to avoid conventional least squares and gradient identification methods which require uni-modal and double differentiable objective functions, this work proposes a modified differential evolution...... inclusion of new data within an error metric. This paper presents results of identification of a time-varying SDOF system with Coulomb friction using simulated noise-free and noisy data for the case of time-varying friction coefficient, stiffness and damping. The obtained results are promising and the focus...

  14. Convenience experimentation.

    Science.gov (United States)

    Krohs, Ulrich

    2012-03-01

    Systems biology aims at explaining life processes by means of detailed models of molecular networks, mainly on the whole-cell scale. The whole cell perspective distinguishes the new field of systems biology from earlier approaches within molecular cell biology. The shift was made possible by the high throughput methods that were developed for gathering 'omic' (genomic, proteomic, etc.) data. These new techniques are made commercially available as semi-automatic analytic equipment, ready-made analytic kits and probe arrays. There is a whole industry of supplies for what may be called convenience experimentation. My paper inquires some epistemic consequences of strong reliance on convenience experimentation in systems biology. In times when experimentation was automated to a lesser degree, modeling and in part even experimentation could be understood fairly well as either being driven by hypotheses, and thus proceed by the testing of hypothesis, or as being performed in an exploratory mode, intended to sharpen concepts or initially vague phenomena. In systems biology, the situation is dramatically different. Data collection became so easy (though not cheap) that experimentation is, to a high degree, driven by convenience equipment, and model building is driven by the vast amount of data that is produced by convenience experimentation. This results in a shift in the mode of science. The paper shows that convenience driven science is not primarily hypothesis-testing, nor is it in an exploratory mode. It rather proceeds in a gathering mode. This shift demands another shift in the mode of evaluation, which now becomes an exploratory endeavor, in response to the superabundance of gathered data. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Experimental philosophy.

    Science.gov (United States)

    Knobe, Joshua; Buckwalter, Wesley; Nichols, Shaun; Robbins, Philip; Sarkissian, Hagop; Sommers, Tamler

    2012-01-01

    Experimental philosophy is a new interdisciplinary field that uses methods normally associated with psychology to investigate questions normally associated with philosophy. The present review focuses on research in experimental philosophy on four central questions. First, why is it that people's moral judgments appear to influence their intuitions about seemingly nonmoral questions? Second, do people think that moral questions have objective answers, or do they see morality as fundamentally relative? Third, do people believe in free will, and do they see free will as compatible with determinism? Fourth, how do people determine whether an entity is conscious?

  16. Linear parameter-varying control for engineering applications

    CERN Document Server

    White, Andrew P; Choi, Jongeun

    2013-01-01

    The objective of this brief is to carefully illustrate a procedure of applying linear parameter-varying (LPV) control to a class of dynamic systems via a systematic synthesis of gain-scheduling controllers with guaranteed stability and performance. The existing LPV control theories rely on the use of either H-infinity or H2 norm to specify the performance of the LPV system.  The challenge that arises with LPV control for engineers is twofold. First, there is no systematic procedure for applying existing LPV control system theory to solve practical engineering problems from modeling to control design. Second, there exists no LPV control synthesis theory to design LPV controllers with hard constraints. For example, physical systems usually have hard constraints on their required performance outputs along with their sensors and actuators. Furthermore, the H-infinity and H2 performance criteria cannot provide hard constraints on system outputs. As a result, engineers in industry could find it difficult to utiliz...

  17. Machine Induced Experimental Background Conditions in the LHC

    CERN Document Server

    Levinsen, Yngve Inntjore; Stapnes, Steinar

    2012-09-19

    The Large Hadron Collider set a new energy record for particle accelerators in late 2009, breaking the previous record held by Tevatron of 2 TeV collision energy. The LHC today operates at a collision energy of 7 TeV. With higher beam energy and intensity, measures have to be taken to ensure optimal experimental conditions and safety of the machine and detectors. Machine induced experimental background can severely reduce the quality of experimental triggers and track reconstruction. In a worst case, the radiation levels can be damaging for some of the subdetectors. The LHC is a particular challenge in this regard due to the vastly different operating conditions of the different experiments. The nominal luminosity varies by four orders of magnitude. The unprecedented stored beam energy and the amount of superconducting elements can make it challenging to protect the accelerator itself as well. In this work we have simulated and measured the machine induced background originating from various sources: the beam...

  18. Molecular mechanisms of drug resistance in natural Leishmania populations vary with genetic background.

    Directory of Open Access Journals (Sweden)

    Saskia Decuypere

    Full Text Available The evolution of drug-resistance in pathogens is a major global health threat. Elucidating the molecular basis of pathogen drug-resistance has been the focus of many studies but rarely is it known whether a drug-resistance mechanism identified is universal for the studied pathogen; it has seldom been clarified whether drug-resistance mechanisms vary with the pathogen's genotype. Nevertheless this is of critical importance in gaining an understanding of the complexity of this global threat and in underpinning epidemiological surveillance of pathogen drug resistance in the field. This study aimed to assess the molecular and phenotypic heterogeneity that emerges in natural parasite populations under drug treatment pressure. We studied lines of the protozoan parasite Leishmania (L. donovani with differential susceptibility to antimonial drugs; the lines being derived from clinical isolates belonging to two distinct genetic populations that circulate in the leishmaniasis endemic region of Nepal. Parasite pathways known to be affected by antimonial drugs were characterised on five experimental levels in the lines of the two populations. Characterisation of DNA sequence, gene expression, protein expression and thiol levels revealed a number of molecular features that mark antimonial-resistant parasites in only one of the two populations studied. A final series of in vitro stress phenotyping experiments confirmed this heterogeneity amongst drug-resistant parasites from the two populations. These data provide evidence that the molecular changes associated with antimonial-resistance in natural Leishmania populations depend on the genetic background of the Leishmania population, which has resulted in a divergent set of resistance markers in the Leishmania populations. This heterogeneity of parasite adaptations provides severe challenges for the control of drug resistance in the field and the design of molecular surveillance tools for widespread

  19. Experimental guidelines

    International Nuclear Information System (INIS)

    1997-01-01

    The paper proposes a model experimental design to study the effects of pesticides on particular ecosystem. It takes maize as a model crop and an alternative crop while studying the adverse effects on untargeted arthropods, residues in the soil and other plants. 5 refs, 7 figs

  20. Experimental studies

    International Nuclear Information System (INIS)

    Cowser, K.E.; Stansbury, P.S.; Poston, J.W.; Deus, S.F.; Chen, W.L.; Roswell, R.L.; Goans, R.E.; Cantrell, J.H. Jr.

    1978-01-01

    Spectral fluence measurements in an adult phantom are reported. A NaI(Tl) probe was used in various locations within the phantom and pulse-height spectra were obtained for seven beam configurations and three generating potentials. Some typical spectra results are presented. A comparison of calculated dose to experimental measurements is presented

  1. A thermal model for photovoltaic panels under varying atmospheric conditions

    International Nuclear Information System (INIS)

    Armstrong, S.; Hurley, W.G.

    2010-01-01

    The response of the photovoltaic (PV) panel temperature is dynamic with respect to the changes in the incoming solar radiation. During periods of rapidly changing conditions, a steady state model of the operating temperature cannot be justified because the response time of the PV panel temperature becomes significant due to its large thermal mass. Therefore, it is of interest to determine the thermal response time of the PV panel. Previous attempts to determine the thermal response time have used indoor measurements, controlling the wind flow over the surface of the panel with fans or conducting the experiments in darkness to avoid radiative heat loss effects. In real operating conditions, the effective PV panel temperature is subjected to randomly varying ambient temperature and fluctuating wind speeds and directions; parameters that are not replicated in controlled, indoor experiments. A new thermal model is proposed that incorporates atmospheric conditions; effects of PV panel material composition and mounting structure. Experimental results are presented which verify the thermal behaviour of a photovoltaic panel for low to strong winds.

  2. Bioventing of gasoline-contaminated soil under varied laboratory conditions

    International Nuclear Information System (INIS)

    Hallman, M.; Shewfelt, K.; Lee, H.; Zytner, R.G.

    2002-01-01

    Bioventing is becoming a popular in situ soil remediation technology for the treatment of hydrocarbon-contaminated soil. Bioventing relies on enhancing the growth of indigenous microorganisms, which can mineralize the contaminant in the presence of sufficient nutrients. Although bioventing is currently being used as a remediation technology, there are some important questions that remain to be answered in order to optimize the process. These questions include the optimum soil moisture content, type and amount of nutrients necessary, and the best means of producing these conditions in the field. To address these questions, two distinct phases of experiments were conducted. The first experimental phase was designed to determine the optimum moisture content, C:N ratio and form of nitrogen supply for this soil. Using approximately 200g of contaminated soil in each of a series of sealed respirometers, microbial degradation of gasoline under bioventing conditions was quantified for C:N ratios of 5, 10 and 20:1, using varying mixtures of NH 4 + - and NO 3 - -N. The results of the studies indicated that the optimum soil moisture content was 15 wt%, with a C:N ratio of 10:1, using a 100% ammonium application. Using the results of the first phase, a second phase of laboratory research was initiated. Five mesoscale reactors have been developed to simulate the bioventing process that takes place in the field. These reactors are filled with approximately 4kg of gasoline-contaminated soil. The initial results are favourable. (author)

  3. A Novel Time-Varying Friction Compensation Method for Servomechanism

    Directory of Open Access Journals (Sweden)

    Bin Feng

    2015-01-01

    Full Text Available Friction is an inevitable nonlinear phenomenon existing in servomechanisms. Friction errors often affect their motion and contour accuracies during the reverse motion. To reduce friction errors, a novel time-varying friction compensation method is proposed to solve the problem that the traditional friction compensation methods hardly deal with. This problem leads to an unsatisfactory friction compensation performance and the motion and contour accuracies cannot be maintained effectively. In this method, a trapezoidal compensation pulse is adopted to compensate for the friction errors. A generalized regression neural network algorithm is used to generate the optimal pulse amplitude function. The optimal pulse duration function and the pulse amplitude function can be established by the pulse characteristic parameter learning and then the optimal friction compensation pulse can be generated. The feasibility of friction compensation method was verified on a high-precision X-Y worktable. The experimental results indicated that the motion and contour accuracies were improved greatly with reduction of the friction errors, in different working conditions. Moreover, the overall friction compensation performance indicators were decreased by more than 54% and this friction compensation method can be implemented easily on most of servomechanisms in industry.

  4. Fast space-varying convolution using matrix source coding with applications to camera stray light reduction.

    Science.gov (United States)

    Wei, Jianing; Bouman, Charles A; Allebach, Jan P

    2014-05-01

    Many imaging applications require the implementation of space-varying convolution for accurate restoration and reconstruction of images. Here, we use the term space-varying convolution to refer to linear operators whose impulse response has slow spatial variation. In addition, these space-varying convolution operators are often dense, so direct implementation of the convolution operator is typically computationally impractical. One such example is the problem of stray light reduction in digital cameras, which requires the implementation of a dense space-varying deconvolution operator. However, other inverse problems, such as iterative tomographic reconstruction, can also depend on the implementation of dense space-varying convolution. While space-invariant convolution can be efficiently implemented with the fast Fourier transform, this approach does not work for space-varying operators. So direct convolution is often the only option for implementing space-varying convolution. In this paper, we develop a general approach to the efficient implementation of space-varying convolution, and demonstrate its use in the application of stray light reduction. Our approach, which we call matrix source coding, is based on lossy source coding of the dense space-varying convolution matrix. Importantly, by coding the transformation matrix, we not only reduce the memory required to store it; we also dramatically reduce the computation required to implement matrix-vector products. Our algorithm is able to reduce computation by approximately factoring the dense space-varying convolution operator into a product of sparse transforms. Experimental results show that our method can dramatically reduce the computation required for stray light reduction while maintaining high accuracy.

  5. Experimental insertions

    International Nuclear Information System (INIS)

    Sandweiss, J.; Kycia, T.F.

    1975-01-01

    A discussion is given of the eight identical experimental insertions for the planned ISABELLE storage rings. Four sets of quadrupole doublets are used to match the β functions in the insertions to the values in the cells, and the total free space available at the crossing point is 40 meters. An asymmetric beam energy operation is planned, which will be useful in a number of experiments

  6. Animal experimentation

    OpenAIRE

    Laz, Alak; Cholakova, Tanya Stefanova; Vrablova, Sofia; Arshad, Naverawaheed

    2016-01-01

    Animal experimentation is a crucial part of medical science. One of the ways to define it is any scientific experiment conducted for research purposes that cause any kind of pain or suffering to animals. Over the years, the new discovered drugs or treatments are first applied on animals to test their positive outcomes to be later used by humans. There is a debate about violating ethical considerations by exploiting animals for human benefits. However, different ethical theories have been made...

  7. Animal experimentation.

    Science.gov (United States)

    Kolar, Roman

    2006-01-01

    Millions of animals are used every year in often times extremely painful and distressing scientific procedures. Legislation of animal experimentation in modern societies is based on the supposition that this is ethically acceptable when certain more or less defined formal (e.g. logistical, technical) demands and ethical principles are met. The main parameters in this context correspond to the "3Rs" concept as defined by Russel and Burch in 1959, i.e. that all efforts to replace, reduce and refine experiments must be undertaken. The licensing of animal experiments normally requires an ethical evaluation process, often times undertaken by ethics committees. The serious problems in putting this idea into practice include inter alia unclear conditions and standards for ethical decisions, insufficient management of experiments undertaken for specific (e.g. regulatory) purposes, and conflicts of interest of ethics committees' members. There is an ongoing societal debate about ethical issues of animal use in science. Existing EU legislation on animal experimentation for cosmetics testing is an example of both the public will for setting clear limits to animal experiments and the need to further critically examine other fields and aspects of animal experimentation.

  8. An integrative time-varying frequency detection and channel sounding method for dynamic plasma sheath

    Science.gov (United States)

    Shi, Lei; Yao, Bo; Zhao, Lei; Liu, Xiaotong; Yang, Min; Liu, Yanming

    2018-01-01

    The plasma sheath-surrounded hypersonic vehicle is a dynamic and time-varying medium and it is almost impossible to calculate time-varying physical parameters directly. The in-fight detection of the time-varying degree is important to understand the dynamic nature of the physical parameters and their effect on re-entry communication. In this paper, a constant envelope zero autocorrelation (CAZAC) sequence based on time-varying frequency detection and channel sounding method is proposed to detect the plasma sheath electronic density time-varying property and wireless channel characteristic. The proposed method utilizes the CAZAC sequence, which has excellent autocorrelation and spread gain characteristics, to realize dynamic time-varying detection/channel sounding under low signal-to-noise ratio in the plasma sheath environment. Theoretical simulation under a typical time-varying radio channel shows that the proposed method is capable of detecting time-variation frequency up to 200 kHz and can trace the channel amplitude and phase in the time domain well under -10 dB. Experimental results conducted in the RF modulation discharge plasma device verified the time variation detection ability in practical dynamic plasma sheath. Meanwhile, nonlinear phenomenon of dynamic plasma sheath on communication signal is observed thorough channel sounding result.

  9. Partially linear varying coefficient models stratified by a functional covariate

    KAUST Repository

    Maity, Arnab; Huang, Jianhua Z.

    2012-01-01

    We consider the problem of estimation in semiparametric varying coefficient models where the covariate modifying the varying coefficients is functional and is modeled nonparametrically. We develop a kernel-based estimator of the nonparametric

  10. The challenge of neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, Christine

    1995-09-15

    Neutrinos'', Maurice Goldhaber once remarked, ''are remarkable particles: they induce courage in theoreticians and perseverance in experimenters''. They are also no strangers to controversy, for they were in a sense born amidst it, and as recent work on neutrino oscillations demonstrates they continue to fuel debate. This is of course largely to do with the fact that neutrinos have no electric charge and experience only the weak nuclear force, making them supremely difficult to detect. The debates surrounding neutrinos began in the first decades of the 20th century, before the particle had even been thought of. Studies pioneered by Lise Meitner and Otto Hahn suggested that the electrons emitted in beta-decay emerged with discrete energies. In these experiments a spectrometer bent the electrons according to their energy, and a photographic plate detected the electrons emerging through a movable slit, so yielding ''lines'' at various energies. But when James Chadwick used a point counter instead of a photographic plate, he could not find ''the ghost of a line''. Instead, he convinced himself that the energy of the beta-decay electrons varies continuously up to a maximum, with peaks (''lines'') at only a few energies. And he was able to explain how the photographic technique could ''fake'' lines through its great sensitivity to small changes in intensity. The First World War interrupted these investigations, but afterwards arguments between a continuous energy spectrum and discrete lines continued until 1927, when Charles Drummond Ellis and William Wooster at Cambridge published results from a definitive experiment in which they measured the total electron energy in a single decay process. If the electrons always started out with the same energy but lost varying amounts in subsidiary processes to give many lines, as Meitner believed, then the result would equal the maximum at the end of the spectrum.

  11. An Evaluation of ChalleNGe Graduates DOD Employability

    Science.gov (United States)

    2018-01-22

    initial reading and applied math TABE scores are more likely to complete ChalleNGe. In addition, those graduates who begin ChalleNGe with higher TABE...each site is given discretion in how it structures its program. As a result, the academic goals of the ChalleNGe sites vary. Some seek to have...students arrive at ChalleNGe at low levels of reading comprehension, writing, and basic math ; they simply are not ready to acquire a second language

  12. Comparison of Linear Microinstability Calculations of Varying Input Realism

    International Nuclear Information System (INIS)

    Rewoldt, G.

    2003-01-01

    The effect of varying ''input realism'' or varying completeness of the input data for linear microinstability calculations, in particular on the critical value of the ion temperature gradient for the ion temperature gradient mode, is investigated using gyrokinetic and gyrofluid approaches. The calculations show that varying input realism can have a substantial quantitative effect on the results

  13. Comparison of linear microinstability calculations of varying input realism

    International Nuclear Information System (INIS)

    Rewoldt, G.; Kinsey, J.E.

    2004-01-01

    The effect of varying 'input realism' or varying completeness of the input data for linear microinstability calculations, in particular on the critical value of the ion temperature gradient for the ion temperature gradient mode, is investigated using gyrokinetic and gyrofluid approaches. The calculations show that varying input realism can have a substantial quantitative effect on the results

  14. Preclinical electrogastrography in experimental pigs

    Science.gov (United States)

    Květina, Jaroslav; Varayil, Jithinraj Edakkanambeth; Ali, Shahzad Marghoob; Kuneš, Martin; Bureš, Jan; Tachecí, Ilja; Rejchrt, Stanislav; Kopáčová, Marcela

    2010-01-01

    Surface electrogastrography (EGG) is a non-invasive means of recording gastric myoelectric activity or slow waves from cutaneous leads placed over the stomach. This paper provides a comprehensive review of preclinical EGG. Our group recently set up and worked out the methods for EGG in experimental pigs. We gained our initial experience in the use of EGG in assessment of porcine gastric myoelectric activity after volume challenge and after intragastric administration of itopride and erythromycin. The mean dominant frequency in pigs is comparable with that found in humans. EGG in experimental pigs is feasible. Experimental EGG is an important basis for further preclinical projects in pharmacology and toxicology. PMID:21217873

  15. Dual Extended Kalman Filter for the Identification of Time-Varying Human Manual Control Behavior

    Science.gov (United States)

    Popovici, Alexandru; Zaal, Peter M. T.; Pool, Daan M.

    2017-01-01

    A Dual Extended Kalman Filter was implemented for the identification of time-varying human manual control behavior. Two filters that run concurrently were used, a state filter that estimates the equalization dynamics, and a parameter filter that estimates the neuromuscular parameters and time delay. Time-varying parameters were modeled as a random walk. The filter successfully estimated time-varying human control behavior in both simulated and experimental data. Simple guidelines are proposed for the tuning of the process and measurement covariance matrices and the initial parameter estimates. The tuning was performed on simulation data, and when applied on experimental data, only an increase in measurement process noise power was required in order for the filter to converge and estimate all parameters. A sensitivity analysis to initial parameter estimates showed that the filter is more sensitive to poor initial choices of neuromuscular parameters than equalization parameters, and bad choices for initial parameters can result in divergence, slow convergence, or parameter estimates that do not have a real physical interpretation. The promising results when applied to experimental data, together with its simple tuning and low dimension of the state-space, make the use of the Dual Extended Kalman Filter a viable option for identifying time-varying human control parameters in manual tracking tasks, which could be used in real-time human state monitoring and adaptive human-vehicle haptic interfaces.

  16. Experimental Techniques

    International Nuclear Information System (INIS)

    Fournier, D.; Serin, L.

    1995-01-01

    Experimental techniques to be used in the new generation of high energy physics are presented. The emphasis is put on the new ATLAS and CMS detectors for the CERN LHC. For the most important elements of these detectors, a description of the underlying physics processes is given, sometimes with reference to comparable detectors used in the past. Some comparative global performances of the two detectors are also given, with reference to benchmark physics processes (detection of the Higgs boson in various mass regions, etc). (author)

  17. ITER safety challenges and opportunities

    International Nuclear Information System (INIS)

    Piet, S.J.

    1992-01-01

    This paper reports on results of the Conceptual Design Activity (CDA) for the International Thermonuclear Experimental Reactor (ITER) suggest challenges and opportunities. ITER is capable of meeting anticipated regulatory dose limits, but proof is difficult because of large radioactive inventories needing stringent radioactivity confinement. Much research and development (R ampersand D) and design analysis is needed to establish that ITER meets regulatory requirements. There is a further oportunity to do more to prove more of fusion's potential safety and environmental advantages and maximize the amount of ITER technology on the path toward fusion power plants. To fulfill these tasks, three programmatic challenges and three technical challenges must be overcome. The first step is to fund a comprehensive safety and environmental ITER R ampersand D plan. Second is to strengthen safety and environment work and personnel in the international team. Third is to establish an external consultant group to advise the ITER Joint Team on designing ITER to meet safety requirements for siting by any of the Parties. The first of three key technical challenges is plasma engineering - burn control, plasma shutdown, disruptions, tritium burn fraction, and steady state operation. The second is the divertor, including tritium inventory, activation hazards, chemical reactions, and coolant disturbances. The third technical challenge is optimization of design requirements considering safety risk, technical risk, and cost

  18. Evolution of perturbation in charge-varying dusty plasmas

    International Nuclear Information System (INIS)

    Popel, S.I.; Golub, A.P.; Losseva, T.V.; Bingham, R.; Benkadda, S.

    2001-01-01

    The nonstationary problem of the evolution of perturbation and its transformation into nonlinear wave structure in dusty plasmas is considered. For this purpose two one-dimensional models based on a set of fluid equations, Poisson's equation, and a charging equation for dust are developed. The first (simplified) model corresponds to the case [Popel et al., Phys. Plasmas 3, 4313 (1996)] when exact steady-state shock wave solutions can exist. This simplified model includes variable-charged dust grains, Boltzmann electrons, and inertial ions. The second (ionization source) model takes into account the variation of the ion density and the ion momentum dissipation due to dust particle charging as well as the source of plasma particles due to ionization process. The computational method for solving the set of equations which describe the evolution in time of a nonlinear structure in a charge-varying dusty plasma is developed. The case of the evolution of an intensive initial nonmoving region with a constant enhanced ion density is investigated on the basis of these two models. The consideration within the ionization source model is performed for the data of the laboratory experiment [Luo et al., Phys. Plasmas 6, 3455 (1999)]. It is shown that the ionization source model allows one to obtain shock structures as a result of evolution of an initial perturbation and to explain the experimental value of the width of the shock wave front. Comparison of the numerical data obtained on the basis of the ionization source model and the simplified model shows that the main characteristic features of the shock structure are the same for both models. Nevertheless, the ionization source model is much more sensitive to the form of the initial perturbation than the simplified model. The solution of the problem of the evolution of perturbation and its transformation into shock wave in charge-varying dusty plasmas opens up possibilities for description of the real phenomena like supernova

  19. Experimental overview

    International Nuclear Information System (INIS)

    Nagamiya, Shoji

    1992-01-01

    Five years ago the first heavy-ion beams were accelerated at both the BNL-AGS and the CERN-SPS. This conference is the 5th anniversary in the experimental field. Currently, four experimental groups (E802/E859, E810, E814, E858) are taking data at BNL and eight groups (NA34-3, NA44, NA45, NA35, NA36, NA38, WA80/WA93, WA85) at CERN. Au and Pb beams are about to come, and a lot of activities are going on for RHIC and LHC. The purpose of this talk is to overview where we are, in particular, by looking at the past data. In this talk, the data of proton rapidity distributions are reviewed first to study nuclear transparency, then, the data of energy spectra and slopes, HBT and anti d production are discussed in connection with the evolution of the collision. Third, the data of strangeness production are described. Finally, the status of J/ψ and that of soft photons and electron pairs are briefly overviewed. (orig.)

  20. Holographic cinematography of time-varying reflecting and time-varying phase objects using a Nd:YAG laser

    Science.gov (United States)

    Decker, A. J.

    1982-01-01

    The use of a Nd:YAG laser to record holographic motion pictures of time-varying reflecting objects and time-varying phase objects is discussed. Sample frames from both types of holographic motion pictures are presented. The holographic system discussed is intended for three-dimensional flow visualization of the time-varying flows that occur in jet-engine components.

  1. Hierarchical classification of dynamically varying radar pulse repetition interval modulation patterns.

    Science.gov (United States)

    Kauppi, Jukka-Pekka; Martikainen, Kalle; Ruotsalainen, Ulla

    2010-12-01

    The central purpose of passive signal intercept receivers is to perform automatic categorization of unknown radar signals. Currently, there is an urgent need to develop intelligent classification algorithms for these devices due to emerging complexity of radar waveforms. Especially multifunction radars (MFRs) capable of performing several simultaneous tasks by utilizing complex, dynamically varying scheduled waveforms are a major challenge for automatic pattern classification systems. To assist recognition of complex radar emissions in modern intercept receivers, we have developed a novel method to recognize dynamically varying pulse repetition interval (PRI) modulation patterns emitted by MFRs. We use robust feature extraction and classifier design techniques to assist recognition in unpredictable real-world signal environments. We classify received pulse trains hierarchically which allows unambiguous detection of the subpatterns using a sliding window. Accuracy, robustness and reliability of the technique are demonstrated with extensive simulations using both static and dynamically varying PRI modulation patterns. Copyright © 2010 Elsevier Ltd. All rights reserved.

  2. Simulation and experimental study of a solar heat pump desalination system

    Energy Technology Data Exchange (ETDEWEB)

    Hawlader, M.N.A.; Tjandra, Tobias Bestari [Dept. of Mechanical Engineering, National Univ. of Singapore, Singapore (Singapore)

    2008-07-01

    With the rising price of oil and gas, the energy cost of desalination process increases significantly. Also, the consumption of fuel to provide thermal and electrical energy in a desalination process will pollute the environment. Therefore, it is necessary to find a new source of energy which is clean and renewable. Solar energy fulfills this challenge to a great extent. An experimental rig was constructed in order to investigate the use of solar energy in desalination. A series of experiments were performed under the meteorological conditions of Singapore. A simulation study was then performed for the system, and comparisons of the predicted and experimental results showed good agreement. The experimental system is capable of producing 1 liter of water per hour. The system has a coefficient of performance that varies from 5 to 9, and a performance ratio of 0.6 to 1.38. (orig.)

  3. Decommissioning - The worldwide challenge

    International Nuclear Information System (INIS)

    McKeown, John

    2002-01-01

    Full text: Whatever the future may hold for nuclear power, there are closed or ageing nuclear facilities in many countries around the world. While these may be in safe care and maintenance at present, a sustainable long term solution is required. Facilities need to be decommissioned, contaminated land remediated, and wastes conditioned for safe storage or disposal. Practical nuclear site restoration has been demonstrated internationally. This experience has revealed generic challenges in dealing with old, often experimental, facilities. These include: Facilities not designed for ease of decommissioning; Records of plant construction and operation, and of the materials utilised and wastes produced, not to modern standards; Fuels and wastes stored for long periods in less than optimal conditions, leading to deterioration and handling problems; The historic use of experimental fuels and materials, giving rise to unique waste streams requiring unique waste management solutions; The application of modern safety and environmental standards to plant which dates from the 1940s, 50s and 60s, requiring investment before decommissioning can even commence. These problems can be tackled, as examples from UKAEA's own programme will illustrate. But two fundamental issues must be recognised and considered. First, the costs of decommissioning older facilities are very high, and may place a heavy burden on national budgets, despite using best efforts to control them. We can limit these costs by learning from one another's experience and sharing the development of new techniques and technologies. UKAEA has already initiated a programme of international collaboration, and hopes that other IAEA countries will be encouraged to follow suit. But whilst the costs of decommissioning may be high, the process normally meets with public acceptance. This is seldom the case for long term waste storage or disposal. Until waste management routes are available - either nationally or internationally

  4. Experimental techniques

    International Nuclear Information System (INIS)

    Roussel-Chomaz, P.

    2007-01-01

    This lecture presents the experimental techniques, developed in the last 10 or 15 years, in order to perform a new class of experiments with exotic nuclei, where the reactions induced by these nuclei allow to get information on their structure. A brief review of the secondary beams production methods will be given, with some examples of facilities in operation or under project. The important developments performed recently on cryogenic targets will be presented. The different detection systems will be reviewed, both the beam detectors before the targets, and the many kind of detectors necessary to detect all outgoing particles after the reaction: magnetic spectrometer for the heavy fragment, detection systems for the target recoil nucleus, γ detectors. Finally, several typical examples of experiments will be detailed, in order to illustrate the use of each detector either alone, or in coincidence with others. (author)

  5. The concentration of plasma metabolites varies throughout reproduction and affects offspring number in wild brown trout (Salmo trutta).

    Science.gov (United States)

    Gauthey, Zoé; Freychet, Marine; Manicki, Aurélie; Herman, Alexandre; Lepais, Olivier; Panserat, Stéphane; Elosegi, Arturo; Tentelier, Cédric; Labonne, Jacques

    2015-06-01

    In wild populations, measuring energy invested in the reproduction and disentangling investment in gametes versus investment in reproductive behavior (such as intrasexual competition or intersexual preference) remain challenging. In this study, we investigated the energy expenditure in brown trout reproductive behavior by using two proxies: variation in weight and variation of plasma metabolites involved in energy production, over the course of reproductive season in a semi natural experimental river. We estimated overall reproductive success using genetic assignment at the end of the reproductive season. Results show that triglycerides and free fatty acid concentrations vary negatively during reproduction, while amino-acids and glucose concentrations remain stable. Decrease in triglyceride and free fatty acid concentrations during reproduction is not related to initial concentration levels or to weight variation. Both metabolite concentration variations and weight variations are correlated to the number of offspring produced, which could indicate that gametic and behavioral reproductive investments substantially contribute to reproductive success in wild brown trout. This study opens a path to further investigate variations in reproductive investment in wild populations. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Adaptive Neural Network Control for Nonlinear Hydraulic Servo-System with Time-Varying State Constraints

    Directory of Open Access Journals (Sweden)

    Shu-Min Lu

    2017-01-01

    Full Text Available An adaptive neural network control problem is addressed for a class of nonlinear hydraulic servo-systems with time-varying state constraints. In view of the low precision problem of the traditional hydraulic servo-system which is caused by the tracking errors surpassing appropriate bound, the previous works have shown that the constraint for the system is a good way to solve the low precision problem. Meanwhile, compared with constant constraints, the time-varying state constraints are more general in the actual systems. Therefore, when the states of the system are forced to obey bounded time-varying constraint conditions, the high precision tracking performance of the system can be easily realized. In order to achieve this goal, the time-varying barrier Lyapunov function (TVBLF is used to prevent the states from violating time-varying constraints. By the backstepping design, the adaptive controller will be obtained. A radial basis function neural network (RBFNN is used to estimate the uncertainties. Based on analyzing the stability of the hydraulic servo-system, we show that the error signals are bounded in the compacts sets; the time-varying state constrains are never violated and all singles of the hydraulic servo-system are bounded. The simulation and experimental results show that the tracking accuracy of system is improved and the controller has fast tracking ability and strong robustness.

  7. Ansiedade experimental humana Human experimental anxiety

    Directory of Open Access Journals (Sweden)

    Frederico Guilherme Graeff

    2007-01-01

    Full Text Available CONTEXTO: A ansiedade experimental no ser humano constitui-se em ponte entre os modelos animais e os ensaios clínicos. OBJETIVO: Este artigo focaliza métodos químicos e psicológicos utilizados para provocar ansiedade experimental em seres humanos. MÉTODOS: Realizou-se revisão seletiva da literatura. RESULTADOS: Os desafios farmacológicos têm sido usados principalmente para induzir ataques de pânico em pacientes com transtorno de pânico, os quais são mais sensíveis a eles que indivíduos normais ou pacientes portadores de outros transtornos psiquiátricos. Uma das mais importantes contribuições deste método é a de ter mostrado que os agentes panicogênicos mais seletivos, como o lactato ou a inalação de CO2, não ativam o eixo hormonal do estresse. Entre os métodos psicológicos, destacam-se o condicionamento de respostas elétricas da condutância da pele, cujo perfil farmacológico se aproxima daquele do transtorno de ansiedade generalizada, e o teste da simulação do falar em público, cuja farmacologia é semelhante à do transtorno de pânico. CONCLUSÕES: Tais resultados salientam a diferença entre a neurobiologia da ansiedade e a do pânico.BACKGROUND: Human experimental anxiety methods bridge the gap between animal models and clinical assays. OBJECTIVE: This article is focused on chemical and psychological procedures used to generate experimental anxiety in human beings. METHODS: A selective review of the literature has been carried out. RESULTS: Pharmacological challenges have been mainly used to induce panic attacks in panic disorder patients, who are more susceptible than normal individuals or patients with other psychiatric disorders. One of the most important contributions of this method is to have shown that the most selective panicogenic agents, such as lactate or CO2 inhalation, do not activate the hormonal stress axis. Among the psychological methods stand the conditioning of the electrical skin conductance

  8. VISIR: Experiences and Challenges

    Directory of Open Access Journals (Sweden)

    Mohamed Tawfik

    2012-02-01

    Full Text Available It is of crucial importance the integration of practical sessions in engineering curricula owing to their significant role in understanding engineering concepts and scientific phenomena. However, the lack of practical sessions due to the high costs of the equipment and the unavailability of instructors has caused a significant declination in experimentation in engineering education. Remote laboratories have tackled this issues providing online reusable and shared workbenches unconstrained by neither geographical nor time considerations. Thereby, they have extremely proliferated among universities and integrated into engineering curricula over the last decade. This contribution compiles diverse experiences based on the deployment of the remote laboratory, Virtual Instrument Systems in Reality (VISIR, on the practices of undergraduate engineering grades at various universities within the VISIR community. It aims to show the impact of its usage on engineering education concerning the assessments of students and teachers as well. In addition, the paper address the next challenges and future works carried out at several universities within the VISIR community.

  9. Modeling and Analysis of a Piezoelectric Energy Harvester with Varying Cross-Sectional Area

    Directory of Open Access Journals (Sweden)

    Maiara Rosa

    2014-01-01

    Full Text Available This paper reports on the modeling and on the experimental verification of electromechanically coupled beams with varying cross-sectional area for piezoelectric energy harvesting. The governing equations are formulated using the Rayleigh-Ritz method and Euler-Bernoulli assumptions. A load resistance is considered in the electrical domain for the estimate of the electric power output of each geometric configuration. The model is first verified against the analytical results for a rectangular bimorph with tip mass reported in the literature. The experimental verification of the model is also reported for a tapered bimorph cantilever with tip mass. The effects of varying cross-sectional area and tip mass on the electromechanical behavior of piezoelectric energy harvesters are also discussed. An issue related to the estimation of the optimal load resistance (that gives the maximum power output on beam shape optimization problems is also discussed.

  10. Stability Control of Force-Reflected Nonlinear Multilateral Teleoperation System under Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Da Sun

    2016-01-01

    Full Text Available A novel control algorithm based on the modified wave-variable controllers is proposed to achieve accurate position synchronization and reasonable force tracking of the nonlinear single-master-multiple-slave teleoperation system and simultaneously guarantee overall system’s stability in the presence of large time-varying delays. The system stability in different scenarios of human and environment situations has been analyzed. The proposed method is validated through experimental work based on the 3-DOF trilateral teleoperation system consisting of three different manipulators. The experimental results clearly demonstrate the feasibility of the proposed algorithm to achieve high transparency and robust stability in nonlinear single-master-multiple-slave teleoperation system in the presence of time-varying delays.

  11. Optimum Design of Multi-Function Robot Arm Gripper for Varying Shape Green Product

    Directory of Open Access Journals (Sweden)

    Razali Zol Bahri

    2016-01-01

    Full Text Available The project focuses on thorough experimentally studies of the optimum design of Multi-function Robot Arm Gripper for varying shape green product. The purpose of this project is to design a few of robot arm gripper for multi-functionally grip a green product with varying shape. The main character of the gripper is that it can automated adjust its finger to suit with the shape of the product. An optimum design of multi-function robot arm gripper is verified through experimental study. The expected result is a series of analytical results on the proposal of gripper design and material that will be selected for the gripper. The analysis of the gripper design proposal by using ANSYS and CATIA software is described in detail in this paper.

  12. The stem factor challenge

    International Nuclear Information System (INIS)

    Russell, M.J.; Steele, R. Jr.; DeWall, K.G.; Watkins, J.C.; Bramwell, D.

    1994-01-01

    One of the most important challenges that still needs to be met in the effort to understand the operation of motor-operated, rising-stem valves is the ability to determine stem factor throughout the valve's load range. The stem factor represents the conversion of operator torque to stem thrust. Determining the stem factor is important because some motor-operated valves (MOVs) cannot be tested in the plant at design basis conditions. The ability of these valves to perform their design basis function (typically, to operate against specified flow and pressure loads) must be ensured by analytical methods or by extrapolating from the results of tests conducted at lower loads. Because the stem factor tends to vary in response to friction and lubrication phenomena that occur during loading and wedging, analytical methods and extrapolation methods have been difficult to develop and implement. Early investigations into variability in the stem factor tended to look only at the tip of the iceberg; they focused on what was happening at torque switch trip, which usually occurs at full wedging. In most stems, the stem factor is better (lower) in the wedging transient than before wedging, so working with torque switch trip data alone led many early researchers to false conclusions about the relationship between stem factor and load. However, research at the Idaho National Engineering Laboratory (INEL) has taken a closer look at what happens during the running portion of the closing stroke along with the wedging portion. This shift in focus is important, because functional failure of a valve typically consists of a failure to isolate flow, not a failure to achieve full wedging. Thus, the stem factor that must be determined for a valve's design basis closing requirements is the one that corresponds with the running load before wedging

  13. Estimating varying coefficients for partial differential equation models.

    Science.gov (United States)

    Zhang, Xinyu; Cao, Jiguo; Carroll, Raymond J

    2017-09-01

    Partial differential equations (PDEs) are used to model complex dynamical systems in multiple dimensions, and their parameters often have important scientific interpretations. In some applications, PDE parameters are not constant but can change depending on the values of covariates, a feature that we call varying coefficients. We propose a parameter cascading method to estimate varying coefficients in PDE models from noisy data. Our estimates of the varying coefficients are shown to be consistent and asymptotically normally distributed. The performance of our method is evaluated by a simulation study and by an empirical study estimating three varying coefficients in a PDE model arising from LIDAR data. © 2017, The International Biometric Society.

  14. Critical velocities in He II for independently varied superfluid and normal fluid velocities

    International Nuclear Information System (INIS)

    Baehr, M.L.

    1984-01-01

    Experiments were performed to measure the critical velocity in pure superflow and compare to the theoretical prediction; to measure the first critical velocity for independently varied superfluid and normal fluid velocities; and to investigate the propagation of the second critical velocity from the thermal counterflow line through the V/sub n/,-V/sub s/ quadrant. The experimental apparatus employed a thermal counterflow heater to adjust the normal fluid velocity, a fountain pump to vary the superfluid velocity, and a level sensing capacitor to measure the superfluid velocity. The results of the pure superfluid critical velocity measurements indicate that this velocity is temperature independent contrary to Schwarz's theory. It was found that the first critical velocity for independently varied V/sub n/ and V/sub s/ could be described by a linear function of V/sub n/ and was otherwise temperature independent. It was found that the second critical velocity could only be distinguished near the thermal counterflow line

  15. Frequency-scanning interferometry using a time-varying Kalman filter for dynamic tracking measurements.

    Science.gov (United States)

    Jia, Xingyu; Liu, Zhigang; Tao, Long; Deng, Zhongwen

    2017-10-16

    Frequency scanning interferometry (FSI) with a single external cavity diode laser (ECDL) and time-invariant Kalman filtering is an effective technique for measuring the distance of a dynamic target. However, due to the hysteresis of the piezoelectric ceramic transducer (PZT) actuator in the ECDL, the optical frequency sweeps of the ECDL exhibit different behaviors, depending on whether the frequency is increasing or decreasing. Consequently, the model parameters of Kalman filter appear time varying in each iteration, which produces state estimation errors with time-invariant filtering. To address this, in this paper, a time-varying Kalman filter is proposed to model the instantaneous movement of a target relative to the different optical frequency tuning durations of the ECDL. The combination of the FSI method with the time-varying Kalman filter was theoretically analyzed, and the simulation and experimental results show the proposed method greatly improves the performance of dynamic FSI measurements.

  16. Modelling and Control of Ionic Electroactive Polymer Actuators under Varying Humidity Conditions

    Directory of Open Access Journals (Sweden)

    S. Sunjai Nakshatharan

    2018-02-01

    Full Text Available In this work, we address the problem of position control of ionic electroactive polymer soft actuators under varying relative humidity conditions. The impact of humidity on the actuation performance of ionic actuators is studied through frequency response and impedance spectroscopy analysis. Considering the uncertain performance of the actuator under varying humidity conditions, an adaptable model using the neural network method is developed. The model uses relative humidity magnitude as one of the model parameters, making it robust to different environmental conditions. Utilizing the model, a closed-loop controller based on the model predictive controller is developed for position control of the actuator. The developed model and controller are experimentally verified and found to be capable of predicting and controlling the actuators with excellent tracking accuracy under relative humidity conditions varying in the range of 10–90%.

  17. Experimental music for experimental physics

    CERN Multimedia

    Rosaria Marraffino

    2014-01-01

    Using the sonification technique, physicist and composer Domenico Vicinanza paid homage to CERN at its 60th anniversary ceremony. After months of hard work, he turned the CERN Convention and LHC data into music.   Click here to download the full score of the "LHChamber music". Every birthday deserves gifts and CERN’s 60th anniversary was no exception. Two gifts were very special, thanks to the hard work of Domenico Vicinanza, a physicist and composer. He created two experimental pieces by applying the sonification technique to the CERN Convention and to data recorded by the four LHC detectors during Run 1. “This technique allows us to ‘hear’ data using an algorithm that translates numbers or letters into notes. It keeps the same information enclosed in a graph or a document, but has a more aesthetic exposition,” explains Domenico Vicinanza. “The result is meant to be a metaphor for scientific cooperation, in which d...

  18. The challenge of neutrinos

    International Nuclear Information System (INIS)

    Sutton, Christine

    1995-01-01

    Neutrinos'', Maurice Goldhaber once remarked, ''are remarkable particles: they induce courage in theoreticians and perseverance in experimenters''. They are also no strangers to controversy, for they were in a sense born amidst it, and as recent work on neutrino oscillations demonstrates they continue to fuel debate. This is of course largely to do with the fact that neutrinos have no electric charge and experience only the weak nuclear force, making them supremely difficult to detect. The debates surrounding neutrinos began in the first decades of the 20th century, before the particle had even been thought of. Studies pioneered by Lise Meitner and Otto Hahn suggested that the electrons emitted in beta-decay emerged with discrete energies. In these experiments a spectrometer bent the electrons according to their energy, and a photographic plate detected the electrons emerging through a movable slit, so yielding ''lines'' at various energies. But when James Chadwick used a point counter instead of a photographic plate, he could not find ''the ghost of a line''. Instead, he convinced himself that the energy of the beta-decay electrons varies continuously up to a maximum, with peaks (''lines'') at only a few energies. And he was able to explain how the photographic technique could ''fake'' lines through its great sensitivity to small changes in intensity. The First World War interrupted these investigations, but afterwards arguments between a continuous energy spectrum and discrete lines continued until 1927, when Charles Drummond Ellis and William Wooster at Cambridge published results from a definitive experiment in which they measured the total electron energy in a single decay process. If the electrons always started out with the same energy but lost varying amounts in subsidiary processes to give many lines, as Meitner believed, then the result would

  19. Effects of varying laser trimming geometries on thin film\\ud resistors

    OpenAIRE

    Alafogianni, Maria; Birkett, Martin; Penlington, Roger

    2017-01-01

    Purpose - This paper studies the effects of varying laser trim patterns on several performance parameters of thin film resistors such as the temperature coefficient of resistance (TCR) and target resistance value.\\ud \\ud Design/methodology/approach - The benefits and limitations of basic trim patterns are taken into consideration and the plunge cut, double plunge cut and the curved L-cut were selected to be modelled and tested experimentally. A computer simulation of the laser trim patterns h...

  20. ITER safety challenges and opportunities

    International Nuclear Information System (INIS)

    Piet, S.J.

    1991-01-01

    Results of the Conceptual Design Activity (CDA) for the International Thermonuclear Experimental Reactor (ITER) suggest challenges and opportunities. ''ITER is capable of meeting anticipated regulatory dose limits,'' but proof is difficult because of large radioactive inventories needing stringent radioactivity confinement. We need much research and development (R ampersand D) and design analysis to establish that ITER meets regulatory requirements. We have a further opportunity to do more to prove more of fusion's potential safety and environmental advantages and maximize the amount of ITER technology on the path toward fusion power plants. To fulfill these tasks, we need to overcome three programmatic challenges and three technical challenges. The first programmatic challenge is to fund a comprehensive safety and environmental ITER R ampersand D plan. Second is to strengthen safety and environment work and personnel in the international team. Third is to establish an external consultant group to advise the ITER Joint Team on designing ITER to meet safety requirements for siting by any of the Parties. The first of the three key technical challenges is plasma engineering -- burn control, plasma shutdown, disruptions, tritium burn fraction, and steady state operation. The second is the divertor, including tritium inventory, activation hazards, chemical reactions, and coolant disturbances. The third technical challenge is optimization of design requirements considering safety risk, technical risk, and cost. Some design requirements are now too strict; some are too lax. Fuel cycle design requirements are presently too strict, mandating inappropriate T separation from H and D. Heat sink requirements are presently too lax; they should be strengthened to ensure that maximum loss of coolant accident temperatures drop

  1. Reproduction losses from slash disposal at the Challenge Experimental Forest

    Science.gov (United States)

    Dale O. Hall; Robert L. Neal

    1963-01-01

    Ponderosa pine, the preferred species, accounted for only 15 percent of the residual coniferous reproduction in seed-tree cuttings. Logging slash was machine-piled to encourage pine regeneration. Slash piling reduced the percentage of plots stocked with conifers from 38 to 12 percent. It destroyed 90 percent of the youngest seedlings but only 27 percent of the saplings...

  2. Experimental practices in economics: a challenge for Psychologist?

    Czech Academy of Sciences Publication Activity Database

    Hertwig, R.; Ortmann, Andreas

    2001-01-01

    Roč. 24, č. 3 (2001), s. 383-403 ISSN 0140-525X R&D Projects: GA AV ČR KSK9058117 Institutional research plan: CEZ:AV0Z7085904 Keywords : psychology * economics Subject RIV: AH - Economics Impact factor: 17.312, year: 2001 http://proquest.umi.com/pqdweb?did=84936553&sid=1&Fmt=2&clientId=45063&RQT=309&VName=PQD

  3. Experimental challenges to stiffness as a transport paradigm

    Science.gov (United States)

    Luce, T. C.; Burrell, K. H.; Holland, C.; Marinoni, A.; Petty, C. C.; Smith, S. P.; Austin, M. E.; Grierson, B. A.; Zeng, L.

    2018-02-01

    Two power scans were carried out in H-mode plasmas in DIII-D; one employed standard co-current neutral beam injection (NBI), while the other used a mixture of co-current and counter-current NBI to scan power while holding the torque to a low fixed value. Analysis of the ion and electron heat transport, ion toroidal angular momentum transport, and thermal deuterium transport from these scans is presented. Invariance of the gradients or gradient scalelengths, as might be expected from stiff transport, was not generally observed. When invariance was seen, it was not accompanied by a strong increase in transport, except in the case of the absolute deuterium ion transport. Conduction in the ion channel is the dominant energy loss mechanism. The variation of the ion heat transport with applied power is similar for the co-injection and fixed torque scans, indicating that E  ×  B shearing is not determining the plasma response to additional power. There is however, a quantitative difference in the transport between the two scans, indicating E  ×  B shearing does play a role in the transport. Comparison of these results with a previous experiment that directly probed stiffness at a single radius leads to the following conclusion: while local stiffness as formally defined may hold, invariance of the gradients or normalized scalelengths does not follow from stiff transport in more practical scaling experiments, such as the power scans discussed here. Possible reasons for the lack of correspondence between the local picture and the global expectations are discussed.

  4. Night Rover Challenge

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the Night Rover Challenge was to foster innovations in energy storage technology. Specifically, this challenge asked competitors to create an energy...

  5. National Drug IQ Challenge

    Science.gov (United States)

    ... National Drug IQ Challenge 2017 Reto nacional del coeficiente intelectual (CI) sobre las drogas y el alcohol 2016 National Drug IQ Challenge 2016 Reto nacional del coeficiente intelectual (CI) sobre las drogas y el alcohol 2015 ...

  6. Nuclear Test-Experimental Science

    International Nuclear Information System (INIS)

    Struble, G.L.; Donohue, M.L.; Bucciarelli, G.; Hymer, J.D.; Kirvel, R.D.; Middleton, C.; Prono, J.; Reid, S.; Strack, B.

    1988-01-01

    Fiscal year 1988 has been a significant, rewarding, and exciting period for Lawrence Livermore National Laboratory's nuclear testing program. It was significant in that the Laboratory's new director chose to focus strongly on the program's activities and to commit to a revitalized emphasis on testing and the experimental science that underlies it. It was rewarding in that revolutionary new measurement techniques were fielded on recent important and highly complicated underground nuclear tests with truly incredible results. And it was exciting in that the sophisticated and fundamental problems of weapons science that are now being addressed experimentally are yielding new challenges and understanding in ways that stimulate and reward the brightest and best of scientists. During FY88 the program was reorganized to emphasize our commitment to experimental science. The name of the program was changed to reflect this commitment, becoming the Nuclear Test-Experimental Science (NTES) Program

  7. How Do Parenting Concepts Vary within and between the Families?

    Science.gov (United States)

    Roskam, Isabelle; Meunier, Jean Christophe

    2009-01-01

    How do parenting concepts vary within and between the families? The present study regards parenting as a complex family process by considering three concepts of parenting: styles, differential treatment and coparenting consistency. A main question was addressed: whether and how these parenting concepts vary within the families towards siblings or…

  8. Specimen loading list for the varying temperature experiment

    International Nuclear Information System (INIS)

    Qualls, A.L.; Sitterson, R.G.

    1998-01-01

    The varying temperature experiment HFIR-RB-13J has been assembled and inserted in the reactor. Approximately 5300 specimens were cleaned, inspected, matched, and loaded into four specimen holders. A listing of each specimen loaded into the steady temperature holder, its position in the capsule, and the identification of the corresponding specimen loaded into the varying temperature holder is presented in this report

  9. Response of rabbits to varying levels of cassava and Leucaena ...

    African Journals Online (AJOL)

    Response of rabbits to varying levels of cassava and Leucaena leucocephala leaf meal diets. ... Bulletin of Animal Health and Production in Africa ... An experiment was carried out to determine the performance, haematology, carcass characteristics and sensory evaluation of meat from rabbits (n = 30) fed varying levels of ...

  10. Analysis of time-varying psoriasis lesion image patterns

    DEFF Research Database (Denmark)

    Maletti, Gabriela Mariel; Ersbøll, Bjarne Kjær; Nielsen, Allan Aasbjerg

    2004-01-01

    The multivariate alteration detection transform is applied to pairs of within and between time varying registered psoriasis image patterns. Color band contribution to the variates explaining maximal change is analyzed.......The multivariate alteration detection transform is applied to pairs of within and between time varying registered psoriasis image patterns. Color band contribution to the variates explaining maximal change is analyzed....

  11. Multivariate time-varying volatility modeling using probabilistic fuzzy systems

    NARCIS (Netherlands)

    Basturk, N.; Almeida, R.J.; Golan, R.; Kaymak, U.

    2016-01-01

    Methods to accurately analyze financial risk have drawn considerable attention in financial institutions. One difficulty in financial risk analysis is the fact that banks and other financial institutions invest in several assets which show time-varying volatilities and hence time-varying financial

  12. Time varying voltage combustion control and diagnostics sensor

    Science.gov (United States)

    Chorpening, Benjamin T [Morgantown, WV; Thornton, Jimmy D [Morgantown, WV; Huckaby, E David [Morgantown, WV; Fincham, William [Fairmont, WV

    2011-04-19

    A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

  13. Natural and experimental Helicobacter mustelae reinfection following successful antimicrobial eradication in ferrets.

    Science.gov (United States)

    Batchelder, M; Fox, J G; Hayward, A; Yan, L; Shames, B; Murphy, J C; Palley, L

    1996-03-01

    Recrudescence or reinfection may occur after eradication of Helicobacter pylori in humans. We used the ferret Helicobacter mustelae model to investigate the effect of prior infection and eradication on reinfection by experimental and natural routes. Two groups of ferrets with naturally acquired H. mustelae infection were treated with an eradication protocol using amoxicillin, metronidazole, and bismuth subsalicylate. The ferrets were monitored for recrudescence by repeated cultures of endoscopic gastric mucosal biopsies. The ferrets were challenged at 17 months (group I) and 6 months (group II) after eradication with a strain of H. mustelae having a distinctive restriction endonuclease analysis pattern. The eradication protocol was repeated to eliminate the infection produced by experimental challenge. The ferrets were then cohoused intermittently with naturally infected ferrets. The original H. mustelae infection was successfully eliminated by the eradication protocol. No recrudescence was observed in group I for 12 months nor for 3 months in group II after eradication. All ferrets became persistently reinfected with the challenge strain. The infection from the challenge strain was eradicated successfully. No ferrets in group I and all ferrets in group II became infected through cohousing. These results suggest that though prior infection with H. mustelae may confer some protection against reinfection, such protection is not universal in all circumstances; that susceptibility to reinfection by contact with infected animals varies between individuals; and that age may be a factor in this individual variability. These results are applicable to studies of reinfection after eradication of H. pylori in humans.

  14. Estimation of thermal sensation during varied air temperature conditions.

    Science.gov (United States)

    Katsuura, T; Tabuchi, R; Iwanaga, K; Harada, H; Kikuchi, Y

    1998-03-01

    Seven male students were exposed to four varied air temperature environments: hot (37 degrees C) to neutral (27 degrees C) (HN), neutral to hot (NH), cool (17 degrees C) to neutral (CN), and neutral to cool (NC). The air temperature was maintained at the first condition for 20 min, then was changed to the second condition after 15 min and was held there for 20 min. Each subject wore a T-shirt, briefs, trunks, and socks. Each sat on a chair and was continuously evaluated for thermal sensation, thermal comfort, and air velocity sensation. Some physiological and thermal parameters were also measured every 5 s during the experiment. The correlation between thermal sensation and skin temperature at 15 sites was found to be poor. The subjects felt much warmer during the rising phase of the air temperature (CN, NH) than during the descending phase (HN, NC) at a given mean skin temperature. However, thermal sensation at the same heat flux or at the same value of the difference between skin and air temperature (delta(Tsk - Ta)) was not so different among the four experimental conditions, and the correlation between thermal sensation and heat flux or delta(Tsk - Ta) was fairly good. The multiple regression equation of the thermal sensation (TS) on 15 sites of skin temperature (Tsk; degrees C) was calculated and the coefficient of determination (R*2) was found to be 0.656. Higher coefficients of determination were found in the equations of thermal sensation for the heat flux (H; kcal.m-2.h-1) at the right and left thighs of the subjects and on delta(Tsk - Ta) (degrees C) at 4 sites. They were as follows: TS = 2.04 - 0.016 Hright - 0.036 Hleft; R*2 = 0.717, TS = 1.649 + 0.013 delta(Tsk - Ta)UpperArm - 0.036 delta(Tsk - Ta)Chest - 0.223 delta(Tsk - Ta)Thigh-0.083 delta(Tsk - Ta)LowerLeg; R*2 = 0.752, respectively.

  15. Reduction of Salmonella Enteritidis in the spleens of hens by bacterins that vary in fimbrial protein SefD

    Science.gov (United States)

    Gene sefD is part of operon sefABCD, and it is required for production of the SEF14 fimbria by Salmonella Enteritidis. We compared strains that varied in SefD content for their ability to reduce recovery of Salmonella Enteritidis from the spleens of hens infected by parenteral challenge. The two bac...

  16. An investigation into the use of a mixture model for simulating the electrical properties of soil with varying effective saturation levels for sub-soil imaging using ECT

    International Nuclear Information System (INIS)

    Hayes, R R; Newill, P A; Podd, F J W; York, T A; Grieve, B D; Dorn, O

    2010-01-01

    A new visualisation tool is being developed for seed breeders, providing on-line data for each individual plant in a screening programme. It will be used to indicate how efficiently each plant utilises the water and nutrients available in the surrounding soil. This will facilitate early detection of desirable genetic traits with the aim of increased efficiency in identification and delivery of tomorrow's drought tolerant food crops. Visualisation takes the form of Electrical Capacitance Tomography (ECT), a non-destructive and non-intrusive imaging technique. Measurements are to be obtained for an individual plant thus allowing water and nutrient absorption levels for an individual specimen to be inferred. This paper presents the inverse problem, discusses the inherent challenges and presents the early experimental results. Two mixture models are evaluated for the prediction of electrical capacitance measurement data for varying effective soil saturation levels using a finite element model implemented in COMSOL Multiphysics. These early studies have given the research team an understanding of the technical challenges that must now be addressed to take the current research into the world of agri-science and food supply.

  17. Robust Stabilization of Nonlinear Systems with Uncertain Varying Control Coefficient

    Directory of Open Access Journals (Sweden)

    Zaiyue Yang

    2014-01-01

    Full Text Available This paper investigates the stabilization problem for a class of nonlinear systems, whose control coefficient is uncertain and varies continuously in value and sign. The study emphasizes the development of a robust control that consists of a modified Nussbaum function to tackle the uncertain varying control coefficient. By such a method, the finite-time escape phenomenon has been prevented when the control coefficient is crossing zero and varying its sign. The proposed control guarantees the asymptotic stabilization of the system and boundedness of all closed-loop signals. The control performance is illustrated by a numerical simulation.

  18. Multi-carrier Communications over Time-varying Acoustic Channels

    Science.gov (United States)

    Aval, Yashar M.

    Acoustic communication is an enabling technology for many autonomous undersea systems, such as those used for ocean monitoring, offshore oil and gas industry, aquaculture, or port security. There are three main challenges in achieving reliable high-rate underwater communication: the bandwidth of acoustic channels is extremely limited, the propagation delays are long, and the Doppler distortions are more pronounced than those found in wireless radio channels. In this dissertation we focus on assessing the fundamental limitations of acoustic communication, and designing efficient signal processing methods that cam overcome these limitations. We address the fundamental question of acoustic channel capacity (achievable rate) for single-input-multi-output (SIMO) acoustic channels using a per-path Rician fading model, and focusing on two scenarios: narrowband channels where the channel statistics can be approximated as frequency- independent, and wideband channels where the nominal path loss is frequency-dependent. In each scenario, we compare several candidate power allocation techniques, and show that assigning uniform power across all frequencies for the first scenario, and assigning uniform power across a selected frequency-band for the second scenario, are the best practical choices in most cases, because the long propagation delay renders the feedback information outdated for power allocation based on the estimated channel response. We quantify our results using the channel information extracted form the 2010 Mobile Acoustic Communications Experiment (MACE'10). Next, we focus on achieving reliable high-rate communication over underwater acoustic channels. Specifically, we investigate orthogonal frequency division multiplexing (OFDM) as the state-of-the-art technique for dealing with frequency-selective multipath channels, and propose a class of methods that compensate for the time-variation of the underwater acoustic channel. These methods are based on multiple

  19. Children's Understanding of Experimental Contrast and Experimental Control: An Inventory for Primary School

    Science.gov (United States)

    Osterhaus, Christopher; Koerber, Susanne; Sodian, Beate

    2015-01-01

    Experimentation skills are a central component of scientific thinking, and many studies have investigated whether and when primary-school children develop adequate experimentation strategies. However, the answers to these questions vary substantially depending on the type of task that is used: while discovery tasks, which require children to…

  20. Uus Eesti film pandi eile Karlovy Varys projektorisse / Kristiina Davidjants

    Index Scriptorium Estoniae

    Davidjants, Kristiina, 1974-

    2008-01-01

    8. juulil esilinastus Karlovy Vary filmifestivalil Rene Vilbre noortefilm "Mina olin siin", mille aluseks on Sass Henno romaan "Mina olin siin. Esimene arest". Film võistleb võistlusprogrammis "East of the West"

  1. Influence of feeding varying crude protein and digestible energy ...

    African Journals Online (AJOL)

    Influence of feeding varying crude protein and digestible energy levels on the development of individual muscles, rate of lean and fat deposition in pigs reared from 9 to 60kg liveweight in a humid tropical environment.

  2. Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions

    Directory of Open Access Journals (Sweden)

    Lang Xue

    2017-06-01

    Full Text Available Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions.

  3. Incipient Fault Detection for Rolling Element Bearings under Varying Speed Conditions.

    Science.gov (United States)

    Xue, Lang; Li, Naipeng; Lei, Yaguo; Li, Ningbo

    2017-06-20

    Varying speed conditions bring a huge challenge to incipient fault detection of rolling element bearings because both the change of speed and faults could lead to the amplitude fluctuation of vibration signals. Effective detection methods need to be developed to eliminate the influence of speed variation. This paper proposes an incipient fault detection method for bearings under varying speed conditions. Firstly, relative residual (RR) features are extracted, which are insensitive to the varying speed conditions and are able to reflect the degradation trend of bearings. Then, a health indicator named selected negative log-likelihood probability (SNLLP) is constructed to fuse a feature set including RR features and non-dimensional features. Finally, based on the constructed SNLLP health indicator, a novel alarm trigger mechanism is designed to detect the incipient fault. The proposed method is demonstrated using vibration signals from bearing tests and industrial wind turbines. The results verify the effectiveness of the proposed method for incipient fault detection of rolling element bearings under varying speed conditions.

  4. Design of 2D Time-Varying Vector Fields

    KAUST Repository

    Chen, Guoning; Kwatra, Vivek; Wei, Li-Yi; Hansen, Charles D.; Zhang, Eugene

    2012-01-01

    Design of time-varying vector fields, i.e., vector fields that can change over time, has a wide variety of important applications in computer graphics. Existing vector field design techniques do not address time-varying vector fields. In this paper, we present a framework for the design of time-varying vector fields, both for planar domains as well as manifold surfaces. Our system supports the creation and modification of various time-varying vector fields with desired spatial and temporal characteristics through several design metaphors, including streamlines, pathlines, singularity paths, and bifurcations. These design metaphors are integrated into an element-based design to generate the time-varying vector fields via a sequence of basis field summations or spatial constrained optimizations at the sampled times. The key-frame design and field deformation are also introduced to support other user design scenarios. Accordingly, a spatial-temporal constrained optimization and the time-varying transformation are employed to generate the desired fields for these two design scenarios, respectively. We apply the time-varying vector fields generated using our design system to a number of important computer graphics applications that require controllable dynamic effects, such as evolving surface appearance, dynamic scene design, steerable crowd movement, and painterly animation. Many of these are difficult or impossible to achieve via prior simulation-based methods. In these applications, the time-varying vector fields have been applied as either orientation fields or advection fields to control the instantaneous appearance or evolving trajectories of the dynamic effects. © 1995-2012 IEEE.

  5. Design of 2D time-varying vector fields.

    Science.gov (United States)

    Chen, Guoning; Kwatra, Vivek; Wei, Li-Yi; Hansen, Charles D; Zhang, Eugene

    2012-10-01

    Design of time-varying vector fields, i.e., vector fields that can change over time, has a wide variety of important applications in computer graphics. Existing vector field design techniques do not address time-varying vector fields. In this paper, we present a framework for the design of time-varying vector fields, both for planar domains as well as manifold surfaces. Our system supports the creation and modification of various time-varying vector fields with desired spatial and temporal characteristics through several design metaphors, including streamlines, pathlines, singularity paths, and bifurcations. These design metaphors are integrated into an element-based design to generate the time-varying vector fields via a sequence of basis field summations or spatial constrained optimizations at the sampled times. The key-frame design and field deformation are also introduced to support other user design scenarios. Accordingly, a spatial-temporal constrained optimization and the time-varying transformation are employed to generate the desired fields for these two design scenarios, respectively. We apply the time-varying vector fields generated using our design system to a number of important computer graphics applications that require controllable dynamic effects, such as evolving surface appearance, dynamic scene design, steerable crowd movement, and painterly animation. Many of these are difficult or impossible to achieve via prior simulation-based methods. In these applications, the time-varying vector fields have been applied as either orientation fields or advection fields to control the instantaneous appearance or evolving trajectories of the dynamic effects.

  6. Design of 2D Time-Varying Vector Fields

    KAUST Repository

    Chen, Guoning

    2012-10-01

    Design of time-varying vector fields, i.e., vector fields that can change over time, has a wide variety of important applications in computer graphics. Existing vector field design techniques do not address time-varying vector fields. In this paper, we present a framework for the design of time-varying vector fields, both for planar domains as well as manifold surfaces. Our system supports the creation and modification of various time-varying vector fields with desired spatial and temporal characteristics through several design metaphors, including streamlines, pathlines, singularity paths, and bifurcations. These design metaphors are integrated into an element-based design to generate the time-varying vector fields via a sequence of basis field summations or spatial constrained optimizations at the sampled times. The key-frame design and field deformation are also introduced to support other user design scenarios. Accordingly, a spatial-temporal constrained optimization and the time-varying transformation are employed to generate the desired fields for these two design scenarios, respectively. We apply the time-varying vector fields generated using our design system to a number of important computer graphics applications that require controllable dynamic effects, such as evolving surface appearance, dynamic scene design, steerable crowd movement, and painterly animation. Many of these are difficult or impossible to achieve via prior simulation-based methods. In these applications, the time-varying vector fields have been applied as either orientation fields or advection fields to control the instantaneous appearance or evolving trajectories of the dynamic effects. © 1995-2012 IEEE.

  7. Do Time-Varying Covariances, Volatility Comovement and Spillover Matter?

    OpenAIRE

    Lakshmi Balasubramanyan

    2005-01-01

    Financial markets and their respective assets are so intertwined; analyzing any single market in isolation ignores important information. We investigate whether time varying volatility comovement and spillover impact the true variance-covariance matrix under a time-varying correlation set up. Statistically significant volatility spillover and comovement between US, UK and Japan is found. To demonstrate the importance of modelling volatility comovement and spillover, we look at a simple portfo...

  8. Performance of a solar chimney by varying design parameters

    CSIR Research Space (South Africa)

    Kumirai, T

    2015-08-01

    Full Text Available the design of solar chimneys to ensure optimal performance. The purpose of this chapter is to discuss the performance of an example solar chimney by varying the design parameters and examining their effects on the interior ventilation performance... chimney by varying design parameters Tichaona Kumirai, Researcher, Built Environment CSIR Jan-Hendrik Grobler, DPSS CSIR Dr D.C.U. Conradie, Senior researcher, Built Environment CSIR 1 Introduction Trombe walls and solar chimneys are not widely...

  9. Perturbation methods and the Melnikov functions for slowly varying oscillators

    International Nuclear Information System (INIS)

    Lakrad, Faouzi; Charafi, Moulay Mustapha

    2005-01-01

    A new approach to obtaining the Melnikov function for homoclinic orbits in slowly varying oscillators is proposed. The present method applies the Lindstedt-Poincare method to determine an approximation of homoclinic solutions. It is shown that the resultant Melnikov condition is the same as that obtained in the usual way involving distance functions in three dimensions by Wiggins and Holmes [Homoclinic orbits in slowly varying oscillators. SIAM J Math Anal 1987;18(3):612

  10. Marketingový mix HC Enegie Karlovy Vary

    OpenAIRE

    Štrobl, Adam

    2016-01-01

    Title: Marketing mix of HC Energie Karlovy Vary Objectives: This thesis is based on a questionnaire responses obtained from HC Energie Karlovy Vary fans. Its objective is focused on evaluation of their opinions on the marketing mix, their subsequent interpretation, and finally even development of recommendations for improvement based on previous analysis. Methods: Two methods are used to analyse the marketing mix. The first method is qualitative participant observation. The second method is a...

  11. Testing for time-varying loadings in dynamic factor models

    DEFF Research Database (Denmark)

    Mikkelsen, Jakob Guldbæk

    Abstract: In this paper we develop a test for time-varying factor loadings in factor models. The test is simple to compute and is constructed from estimated factors and residuals using the principal components estimator. The hypothesis is tested by regressing the squared residuals on the squared...... there is evidence of time-varying loadings on the risk factors underlying portfolio returns for around 80% of the portfolios....

  12. Bounds and asymptotics for orthogonal polynomials for varying weights

    CERN Document Server

    Levin, Eli

    2018-01-01

    This book establishes bounds and asymptotics under almost minimal conditions on the varying weights, and applies them to universality limits and entropy integrals.  Orthogonal polynomials associated with varying weights play a key role in analyzing random matrices and other topics.  This book will be of use to a wide community of mathematicians, physicists, and statisticians dealing with techniques of potential theory, orthogonal polynomials, approximation theory, as well as random matrices. .

  13. Pemodelan Markov Switching Dengan Time-varying Transition Probability

    OpenAIRE

    Savitri, Anggita Puri; Warsito, Budi; Rahmawati, Rita

    2016-01-01

    Exchange rate or currency is an economic variable which reflects country's state of economy. It fluctuates over time because of its ability to switch the condition or regime caused by economic and political factors. The changes in the exchange rate are depreciation and appreciation. Therefore, it could be modeled using Markov Switching with Time-Varying Transition Probability which observe the conditional changes and use information variable. From this model, time-varying transition probabili...

  14. Quantum capacity under adversarial quantum noise: arbitrarily varying quantum channels

    OpenAIRE

    Ahlswede, Rudolf; Bjelakovic, Igor; Boche, Holger; Noetzel, Janis

    2010-01-01

    We investigate entanglement transmission over an unknown channel in the presence of a third party (called the adversary), which is enabled to choose the channel from a given set of memoryless but non-stationary channels without informing the legitimate sender and receiver about the particular choice that he made. This channel model is called arbitrarily varying quantum channel (AVQC). We derive a quantum version of Ahlswede's dichotomy for classical arbitrarily varying channels. This includes...

  15. The GREAT3 challenge

    International Nuclear Information System (INIS)

    Miyatake, H; Mandelbaum, R; Rowe, B

    2014-01-01

    The GRavitational lEnsing Accuracy Testing 3 (GREAT3) challenge is an image analysis competition that aims to test algorithms to measure weak gravitational lensing from astronomical images. The challenge started in October 2013 and ends 30 April 2014. The challenge focuses on testing the impact on weak lensing measurements of realistically complex galaxy morphologies, realistic point spread function, and combination of multiple different exposures. It includes simulated ground- and space-based data. The details of the challenge are described in [1], and the challenge website and its leader board can be found at http://great3challenge.info and http://great3.projects.phys.ucl.ac.uk/leaderboard/, respectively

  16. Computational challenges in modeling gene regulatory events.

    Science.gov (United States)

    Pataskar, Abhijeet; Tiwari, Vijay K

    2016-10-19

    Cellular transcriptional programs driven by genetic and epigenetic mechanisms could be better understood by integrating "omics" data and subsequently modeling the gene-regulatory events. Toward this end, computational biology should keep pace with evolving experimental procedures and data availability. This article gives an exemplified account of the current computational challenges in molecular biology.

  17. Millennium Challenge Account

    National Research Council Canada - National Science Library

    Tarnoff, Curt

    2008-01-01

    .... foreign aid initiative. The Millennium Challenge Account (MCA) provides assistance through a competitive selection process to developing nations that are pursing political and economic reforms in three areas...

  18. Varied Practice in Laparoscopy Training: Beneficial Learning Stimulation or Cognitive Overload?

    Science.gov (United States)

    Spruit, Edward N; Kleijweg, Luca; Band, Guido P H; Hamming, Jaap F

    2016-01-01

    Determining the optimal design for surgical skills training is an ongoing research endeavor. In education literature, varied practice is listed as a positive intervention to improve acquisition of knowledge and motor skills. In the current study we tested the effectiveness of a varied practice intervention during laparoscopy training. Twenty-four trainees (control group) without prior experience received a 3 weeks laparoscopic skills training utilizing four basic and one advanced training task. Twenty-eight trainees (experimental group) received the same training with a random training task schedule, more frequent task switching and inverted viewing conditions on the four basic training tasks, but not the advanced task. Results showed inferior performance of the experimental group on the four basic laparoscopy tasks during training, at the end of training and at a 2 months retention session. We assume the inverted viewing conditions have led to the deterioration of learning in the experimental group because no significant differences were found between groups on the only task that had not been practiced under inverted viewing conditions; the advanced laparoscopic task. Potential moderating effects of inter-task similarity, task complexity, and trainee characteristics are discussed.

  19. Varied Practice in Laparoscopy Training: Beneficial Learning Stimulation or Cognitive Overload?

    Directory of Open Access Journals (Sweden)

    Edward N. eSpruit

    2016-05-01

    Full Text Available AbstractDetermining the optimal design for surgical skills training is an ongoing research endeavor. In education literature, varied practice is listed as a positive intervention to improve acquisition of knowledge and motor skills. In the current study we tested the effectiveness of a varied practice intervention during laparoscopy training. 24 trainees (control group without prior experience received a three week laparoscopic skills training utilizing four basic and one advanced training task. 28 trainees (experimental group received the same training with a random training task schedule, more frequent task switching and inverted viewing conditions on the four basic training tasks, but not the advanced task. Results showed inferior performance of the experimental group on the four basic laparoscopy tasks during training, at the end of training and at a two month retention session. We assume the inverted viewing conditions have led to the deterioration of learning in the experimental group because no significant differences were found between groups on the only task that had not been practiced under inverted viewing conditions; the advanced laparoscopic task. Potential moderating effects of inter-task similarity, task complexity and trainee characteristics are discussed.

  20. First Aid Challenge

    Science.gov (United States)

    Roman, Harry T.

    2011-01-01

    This article describes a challenge wherein students will be asked to design a portable first aid kit that is normally carried in a recreational vehicle (RV), but can also be hand-carried or backpacked off road for distances of approximately 1-2 miles. This can be a very practical challenge for the students because it touches everyone. Everybody…

  1. Virtual Bridge Design Challenge

    Science.gov (United States)

    Mitts, Charles R.

    2013-01-01

    This design/problem-solving activity challenges students to design a replacement bridge for one that has been designated as either structurally deficient or functionally obsolete. The Aycock MS Technology/STEM Magnet Program Virtual Bridge Design Challenge is an authentic introduction to the engineering design process. It is a socially relevant…

  2. Dewey's Challenge to Teachers

    Science.gov (United States)

    Fishman, Stephen M.; McCarthy, Lucille

    2010-01-01

    Given the serious social problems confronting Americans and others worldwide, the authors propose that Dewey's 1932 challenge to teachers is worthy of reconsideration by educators at all levels. In times similar to our own, Dewey challenged teachers to cultivate students' capacities to identify their happiness with what they can do to improve the…

  3. Challenges in fingertip replantation.

    Science.gov (United States)

    Kim, Jin-Soo; Yang, Jae-Won; Lee, Dong-Chul; Ki, Sae-Hwi; Roh, Si-Young

    2013-11-01

    Fingertip amputation is a challenging injury to manage. Among various reconstructive procedures, replantation results in superior outcome, but is seldom considered in many institutions. From the identification of vessel ends to reanastomosis of the submillimeter vessels, fingertip's highly specialized anatomy requires technical excellence. By addressing these anatomic challenges, fingertip replantation can be a routine reconstructive option for microvascular surgeons.

  4. Challenges in Fingertip Replantation

    OpenAIRE

    Kim, Jin-Soo; Yang, Jae-Won; Lee, Dong-Chul; Ki, Sae-Hwi; Roh, Si-Young

    2013-01-01

    Fingertip amputation is a challenging injury to manage. Among various reconstructive procedures, replantation results in superior outcome, but is seldom considered in many institutions. From the identification of vessel ends to reanastomosis of the submillimeter vessels, fingertip's highly specialized anatomy requires technical excellence. By addressing these anatomic challenges, fingertip replantation can be a routine reconstructive option for microvascular surgeons.

  5. Challenge and Change

    Science.gov (United States)

    Mehaffy, George L.

    2012-01-01

    In the past twenty years, various industries have been forever altered by technology: newspapers, book publishing, the photography business, and many more. Higher education too faces unprecedented challenges primarily driven by rapid changes in technology. To meet these challenges and adapt to these changes, new models are needed. Six challenges…

  6. Mediation analysis with time varying exposures and mediators.

    Science.gov (United States)

    VanderWeele, Tyler J; Tchetgen Tchetgen, Eric J

    2017-06-01

    In this paper we consider causal mediation analysis when exposures and mediators vary over time. We give non-parametric identification results, discuss parametric implementation, and also provide a weighting approach to direct and indirect effects based on combining the results of two marginal structural models. We also discuss how our results give rise to a causal interpretation of the effect estimates produced from longitudinal structural equation models. When there are time-varying confounders affected by prior exposure and mediator, natural direct and indirect effects are not identified. However, we define a randomized interventional analogue of natural direct and indirect effects that are identified in this setting. The formula that identifies these effects we refer to as the "mediational g-formula." When there is no mediation, the mediational g-formula reduces to Robins' regular g-formula for longitudinal data. When there are no time-varying confounders affected by prior exposure and mediator values, then the mediational g-formula reduces to a longitudinal version of Pearl's mediation formula. However, the mediational g-formula itself can accommodate both mediation and time-varying confounders and constitutes a general approach to mediation analysis with time-varying exposures and mediators.

  7. Varying ultrasound power level to distinguish surgical instruments and tissue.

    Science.gov (United States)

    Ren, Hongliang; Anuraj, Banani; Dupont, Pierre E

    2018-03-01

    We investigate a new framework of surgical instrument detection based on power-varying ultrasound images with simple and efficient pixel-wise intensity processing. Without using complicated feature extraction methods, we identified the instrument with an estimated optimal power level and by comparing pixel values of varying transducer power level images. The proposed framework exploits the physics of ultrasound imaging system by varying the transducer power level to effectively distinguish metallic surgical instruments from tissue. This power-varying image-guidance is motivated from our observations that ultrasound imaging at different power levels exhibit different contrast enhancement capabilities between tissue and instruments in ultrasound-guided robotic beating-heart surgery. Using lower transducer power levels (ranging from 40 to 75% of the rated lowest ultrasound power levels of the two tested ultrasound scanners) can effectively suppress the strong imaging artifacts from metallic instruments and thus, can be utilized together with the images from normal transducer power levels to enhance the separability between instrument and tissue, improving intraoperative instrument tracking accuracy from the acquired noisy ultrasound volumetric images. We performed experiments in phantoms and ex vivo hearts in water tank environments. The proposed multi-level power-varying ultrasound imaging approach can identify robotic instruments of high acoustic impedance from low-signal-to-noise-ratio ultrasound images by power adjustments.

  8. Employment challenges in the future

    DEFF Research Database (Denmark)

    2011-01-01

    Discussion of challenges in employment challenges in Europe and a brief discription of the Danish flexicurity system......Discussion of challenges in employment challenges in Europe and a brief discription of the Danish flexicurity system...

  9. A receding horizon scheme for discrete-time polytopic linear parameter varying systems in networked architectures

    International Nuclear Information System (INIS)

    Franzè, Giuseppe; Lucia, Walter; Tedesco, Francesco

    2014-01-01

    This paper proposes a Model Predictive Control (MPC) strategy to address regulation problems for constrained polytopic Linear Parameter Varying (LPV) systems subject to input and state constraints in which both plant measurements and command signals in the loop are sent through communication channels subject to time-varying delays (Networked Control System (NCS)). The results here proposed represent a significant extension to the LPV framework of a recent Receding Horizon Control (RHC) scheme developed for the so-called robust case. By exploiting the parameter availability, the pre-computed sequences of one- step controllable sets inner approximations are less conservative than the robust counterpart. The resulting framework guarantees asymptotic stability and constraints fulfilment regardless of plant uncertainties and time-delay occurrences. Finally, experimental results on a laboratory two-tank test-bed show the effectiveness of the proposed approach

  10. Newtonian cosmology with a time-varying constant of gravitation

    International Nuclear Information System (INIS)

    McVittie, G.C.

    1978-01-01

    Newtonian cosmology is based on the Eulerian equations of fluid mechanics combined with Poisson's equation modified by the introduction of a time-varying G. Spherically symmetric model universes are worked out with instantaneously uniform densities. They are indeterminate unless instantaneous uniformity of the pressure is imposed. When G varies as an inverse power of the time, the models can in some cases be shown to depend on the solution of a second-order differential equation which also occurs in the Friedmann models of general relativity. In Section 3, a method for 'passing through' a singularity of this equation is proposed which entails making four arbitrary mathematical assumptions. When G varies as (time) -1 , models with initially cycloidal motion are possible, each cycle becoming longer as time progresses. Finally, gravitation becomes so weak that the model expands to infinity. Kinetic and potential energies for the whole model are derived from the basic equations; their sum is not constant. (author)

  11. Brane world cosmologies with varying speed of light

    International Nuclear Information System (INIS)

    Youm, Donam

    2001-02-01

    We study cosmologies in the Randall-Sundrum models, incorporating the possibility of time-varying speed of light and Newton's constant. The cosmologies with varying speed of light (VSL) were proposed by Moffat and by Albrecht and Magueijo as an alternative to inflation for solving the cosmological problems. We consider the case in which the speed of light varies with time after the radion or the scale of the extra dimension has been stabilized. We elaborate on the conditions under which the flatness problem and the cosmological constant problem can be resolved. Particularly, the VSL cosmologies may provide a possible mechanism for bringing the quantum corrections to the fine-tuned brane tensions after the SUSY breaking under control. (author)

  12. Partially linear varying coefficient models stratified by a functional covariate

    KAUST Repository

    Maity, Arnab

    2012-10-01

    We consider the problem of estimation in semiparametric varying coefficient models where the covariate modifying the varying coefficients is functional and is modeled nonparametrically. We develop a kernel-based estimator of the nonparametric component and a profiling estimator of the parametric component of the model and derive their asymptotic properties. Specifically, we show the consistency of the nonparametric functional estimates and derive the asymptotic expansion of the estimates of the parametric component. We illustrate the performance of our methodology using a simulation study and a real data application.

  13. Varied appearance of lymphoma in patients with AIDS

    International Nuclear Information System (INIS)

    Sider, L.; Weiss, A.

    1988-01-01

    Lymphoma is frequently present in patients with acquired immunodeficiency (AIDS). But unlike in the general population, the appearance of lymphoma in patients with AIDS is extremely varied. The computed tomographic scans, chest radiographs, and subsequent hospital courses of 15 patients with AIDS-related lymphoma are presented. The patients presented with isolated pleural effusion (six patients), pleural and pericardial effusion (one patient), pulmonary infiltrates (five patients), and mediastinal adenopathy (three patients). This varied manner of presentation of lymphoma in AIDS patients should be recognized if diagnosis is to be made in the earlier stages of presentation

  14. Entropy Rate of Time-Varying Wireless Networks

    DEFF Research Database (Denmark)

    Cika, Arta; Badiu, Mihai Alin; Coon, Justin P.

    2018-01-01

    In this paper, we present a detailed framework to analyze the evolution of the random topology of a time-varying wireless network via the information theoretic notion of entropy rate. We consider a propagation channel varying over time with random node positions in a closed space and Rayleigh...... fading affecting the connections between nodes. The existence of an edge between two nodes at given locations is modeled by a Markov chain, enabling memory effects in network dynamics. We then derive a lower and an upper bound on the entropy rate of the spatiotemporal network. The entropy rate measures...

  15. Investigating Time-Varying Drivers of Grid Project Emissions Impacts

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Emily L.; Thayer, Brandon L.; Pal, Seemita; Studarus, Karen E.

    2017-11-15

    The emissions consequences of smart grid technologies depend heavily on their context and vary not only by geographical location, but by time of year. The same technology operated to meet the same objective may increase the emissions associated with energy generation for part of the year and decrease emissions during other times. The Grid Project Impact Quantification (GridPIQ) tool provides the ability to estimate these seasonal variations and garner insight into the time-varying drivers of grid project emissions impacts. This work leverages GridPIQ to examine the emissions implications across years and seasons of adding energy storage technology to reduce daily peak demand in California and New York.

  16. Rate of solidification of aluminium casting in varying wall thickness of cylindrical metallic moulds

    Directory of Open Access Journals (Sweden)

    Katsina Christopher BALA

    2014-02-01

    Full Text Available The quality of final casting mainly depends on the rate of solidification as rapid solidification produces fine grains structures with better mechanical properties. The analysis of heat transfer during the casting and solidification of aluminium alloy as well as the experimental investigation of the rate of solidification in varying thicknesses of cylindrical metallic mould was carried out. The temperature variation with time of the casting was recorded from which cooling curves were obtained for the determination of solidification time of the cast. The results showed that as the cylindrical mould thickness increases the solidification time decreases due to the chilling effect of the mould.

  17. Realization of arbitrarily long focus-depth optical vortices with spiral area-varying zone plates

    Science.gov (United States)

    Zheng, Chenglong; Zang, Huaping; Du, Yanli; Tian, Yongzhi; Ji, Ziwen; Zhang, Jing; Fan, Quanping; Wang, Chuanke; Cao, Leifeng; Liang, Erjun

    2018-05-01

    We provide a methodology to realize an optical vortex with arbitrarily long focus-depth. With a technique of varying each zone area of a phase spiral zone plate one can obtain optics capable of generating ultra-long focus-depth optical vortex from a plane wave. The focal property of such optics was analysed using the Fresnel diffraction theory, and an experimental demonstration was performed to verify its effectiveness. Such optics may bring new opportunity and benefits for optical vortex application such as optical manipulation and lithography.

  18. Numerical modeling of rapidly varying flows using HEC-RAS and WSPG models.

    Science.gov (United States)

    Rao, Prasada; Hromadka, Theodore V

    2016-01-01

    The performance of two popular hydraulic models (HEC-RAS and WSPG) for modeling hydraulic jump in an open channel is investigated. The numerical solutions are compared with a new experimental data set obtained for varying channel bottom slopes and flow rates. Both the models satisfactorily predict the flow depths and location of the jump. The end results indicate that the numerical models output is sensitive to the value of chosen roughness coefficient. For this application, WSPG model is easier to implement with few input variables.

  19. Nuclear Car Wash sensitivity in varying thicknesses of wood and steel cargo

    International Nuclear Information System (INIS)

    Church, J; Slaughter, D; Asztalos, S; Biltoft, P; Descalle, M; Hall, J; Manatt, D; Mauger, J; Norman, E; Petersen, D; Prussin, S

    2006-01-01

    The influence of incident neutron attenuation on signal strengths in the Nuclear Car Wash has been observed experimentally for both wood and steel-pipe mock cargos. Measured decay curves are presented for β-delayed high-energy γ-rays and thermalized neutrons following neutron-induced fission of HEU through varying irradiation lengths. Error rates are extracted for delayed-γ and delayed-n signals integrated to 30 seconds, assuming Gaussian distributions for the active background. The extrapolation to a field system of 1 mA deuterium current and to a 5 kg sample size is discussed

  20. Surface Relaxation and Electronic States of Pt(111) Surface with Varying Slab Thickness

    International Nuclear Information System (INIS)

    Kaushal, Ashok K.; Mullick, Shanta; Ahluwalia, P. K.

    2011-01-01

    Surface relaxation and electronic DOS's of Pt(111) surface have been studied with varying slab thickness using ab-initio SIESTA method. We found the expansion in the top layer and contraction in the subsurface layers of Pt(111) surface. Our results match with the experimental results. Also observing electronic density of states we found that as we increase the thickness of slab, the PDOS of Pt(111) surface goes towards the bulk density of states and Fermi energy shifts towards the bulk fermi energy.

  1. Radioecological challenges for mining

    Energy Technology Data Exchange (ETDEWEB)

    Vesterbacka, P.; Ikaeheimonen, T.K.; Solatie, D. [Radiation and Nuclear Safety Authority (Finland)

    2014-07-01

    In Finland, mining became popular in the mid-1990's when the mining amendments to the law made the mining activities easier for foreign companies. Also the price of the minerals rose and mining in Finland became economically profitable. Expanding mining industry brought new challenges to radiation safety aspect since radioactive substances occur in nearly all minerals. In Finnish soil and bedrock the average crystal abundance of uranium and thorium are 2.8 ppm and 10 ppm, respectively. It cannot be predicted beforehand how radionuclides behave in the mining processes which why they need to be taken into account in mining activities. Radiation and Nuclear Safety Authority (STUK) has given a national guide ST 12.1 based on the Finnish Radiation Act. The guide sets the limits for radiation doses to the public also from mining activities. In general, no measures to limit the radiation exposure are needed, if the dose from the operation liable to cause exposure to natural radiation is no greater than 0.1 mSv per year above the natural background radiation dose. If the exposure of the public may be higher than 0.1 mSv per year, the responsible party must provide STUK a plan describing the measures by which the radiation exposure is to be kept as low as is reasonably achievable. In that case the mining company responsible company has to make a radiological baseline study. The baseline study must focus on the environment that the mining activities may impact. The study describes the occurrence of natural radioactivity in the environment before any mining activities are started. The baseline study lasts usually for two to three years in natural circumstances. Based on the baseline study measurements, detailed information of the existing levels of radioactivity in the environment can be attained. Once the mining activities begin, it is important that the limits are set for the wastewater discharges to the environment and environmental surveillance in the vicinity of

  2. Big Data Challenges

    Directory of Open Access Journals (Sweden)

    Alexandru Adrian TOLE

    2013-10-01

    Full Text Available The amount of data that is traveling across the internet today, not only that is large, but is complex as well. Companies, institutions, healthcare system etc., all of them use piles of data which are further used for creating reports in order to ensure continuity regarding the services that they have to offer. The process behind the results that these entities requests represents a challenge for software developers and companies that provide IT infrastructure. The challenge is how to manipulate an impressive volume of data that has to be securely delivered through the internet and reach its destination intact. This paper treats the challenges that Big Data creates.

  3. The challenges of dismantling

    International Nuclear Information System (INIS)

    Sene, Monique; Lheureux, Yves; Leroyer, Veronique; Rollinger, Francois; Gauthier, Florence; Depauw, Denis; Reynal, Nathalie; Fraysse, Thierry; Burger, Eric; Bertrand, Adrien; Vallat, Christophe; Bernet, Philippe; Eimer, Michel; Boutin, Dominique; Bietrix, Philippe; Richard, Francoise; Piketty, Laurence; Mouchet, Chantal; Charre, Jean-Pierre

    2014-01-01

    This document gathers Power Point presentations which address the contexts and challenges of dismantling (legal framework, safety and radiation protection challenges, waste processing industry), and propose illustrations of dismantling challenges (example of operations to prepare EURODIF dismantling and CLIGEET work-group on EURODIF dismantling, examples of dismantling of EDF installations and CLIs' opinion on the dismantling of EDF installations, Brennilis dismantling follow-up performed by the CLI, examples of dismantling of CEA installations and opinion of a CLI on the dismantling of CEA installations)

  4. Challenges of serious games

    Directory of Open Access Journals (Sweden)

    B. Fernández-Manjón

    2015-11-01

    Full Text Available Although educational games have revealed to be a very effective focus in diverse situations, their use in education is still very limited. In this paper we analyse the main challenges concerning educational games that, from our perspective, have to be approached so that the use of this kind of games can be widespread. These challenges are classified in three main dimensions: socio-cultural, educational and technological. Once the challenges are identified, some possible measures are suggested to address or reduce these problems so that the use of educational games may be widespread.

  5. Overcoming Spurious Regression Using time-Varying Fourier ...

    African Journals Online (AJOL)

    Non-stationary time series data have been traditionally analyzed in the frequency domain by assuming constant amplitudes regardless of the timelag. A new approach called time-varying amplitude method (TVAM) is presented here. Oscillations are analyzed for changes in the magnitude of Fourier Coefficients which are ...

  6. Electromagnetic radiation in a time-varying background medium

    NARCIS (Netherlands)

    Budko, N.V.

    2009-01-01

    Analytical solutions are presented for the electromagnetic radiation by an arbitrary pulsed source into a homogeneous time-varying background medium. In the constant-impedance case an explicit radiation formula is obtained for the synchronous permittivity and permeability described by any positive

  7. Computation of gradually varied flow in compound open channel ...

    Indian Academy of Sciences (India)

    The flow of water in an open channel can be treated as steady, gradually varied flow for ... channel between two nodes is treated as a single reach to calculate the loss ... dition at control points and (iii) critical depth is also required to verify the ...

  8. Adenoma detection rate varies greatly during colonoscopy training

    NARCIS (Netherlands)

    van Doorn, Sascha C.; Klanderman, Robert B.; Hazewinkel, Yark; Fockens, Paul; Dekker, Evelien

    2015-01-01

    The adenoma detection rate (ADR) is considered the most important quality indicator for colonoscopy and varies widely among colonoscopists. It is unknown whether the ADR of gastroenterology consultants can already be predicted during their colonoscopy training. To evaluate the ADR of fellows in

  9. Peer influence on school learning among students of varying socio ...

    African Journals Online (AJOL)

    This study examined peer Influence on School Learning among students of varying socio-economic backgrounds. One hundred and twenty students (60 males and 60 females) with a mean age 15.1 years were randomly selected from four co-educational Secondary Schools in Ikenne Local Government area of Ogun State.

  10. Projected space-time and varying speed of light

    International Nuclear Information System (INIS)

    Iovane, G.; Bellucci, S.; Benedetto, E.

    2008-01-01

    In this paper starting from El Naschie's Cantorian space-time and our model of projected Universe, we consider its properties in connection with varying speed of light. A possible way-out of the related problem is provided by the Fantappie group approach

  11. Frontal Neurons Modulate Memory Retrieval across Widely Varying Temporal Scales

    Science.gov (United States)

    Zhang, Wen-Hua; Williams, Ziv M.

    2015-01-01

    Once a memory has formed, it is thought to undergo a gradual transition within the brain from short- to long-term storage. This putative process, however, also poses a unique problem to the memory system in that the same learned items must also be retrieved across broadly varying time scales. Here, we find that neurons in the ventrolateral…

  12. Time Varying Market Integration and Expected Rteurns in Emerging Markets

    NARCIS (Netherlands)

    de Jong, F.C.J.M.; de Roon, F.A.

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematic risk as measured by their beta relative to the world portfolio as well as on the level of integration in that market.The level of integration is a time-varying variable that depends on the market value

  13. Branching of positive discharge streamers in air at varying pressures

    NARCIS (Netherlands)

    Briels, T.M.P.; Veldhuizen, van E.M.; Ebert, U.M.

    2005-01-01

    The formation of positive streamers in a 17-mm gap in air is studied at pressures varying in the range from 1010 to 100 mbar. An intensified charge coupled device camera is used to image the discharge. At high pressures, the discharge shows many branches, while at low pressure, fewer branches arise.

  14. Conductivity studies of lithium zinc silicate glasses with varying ...

    Indian Academy of Sciences (India)

    WINTEC

    Values of activation energy derived from σd.c., ωh and τ are almost equal within the ... materials can be changed by varying the proportion of the .... The solid line is a guide to the eye. ... does not show a maximum as d.c. conductivity drops to a.

  15. Varying the exchange interaction between NiO nanoparticles

    DEFF Research Database (Denmark)

    Bahl, Christian Robert Haffenden; Mørup, Steen

    2006-01-01

    We demonstrate that exchange interactions between antiferromagnetic nanoparticles of 57Fe-doped NiO can be varied by simple macroscopic treatments. Mössbauer spectroscopy studies of the superparamagnetic relaxation behaviour show that grinding or suspension in water of nanoparticles of NiO can...

  16. Performance and cost implication of finisher turkeys fed varying ...

    African Journals Online (AJOL)

    A 28-day experiment was conducted to determine the effect of feeding varying levels of rice milling waste as a substitute on maize on the performance, nutrient utilization and the economics implication on finisher turkeys. Five turkey finisher diets were formulated by substituting maize with rice milling waste at 0%, 25%, 50%, ...

  17. Sheep response to sugar cane tops supplemented with varying ...

    African Journals Online (AJOL)

    Twenty WAD sheep averaging 10.14kg were randomly divided into four groups of 5 replicates, and each group was fed sugarcane tops (SCT) supplemented with varying levels (0%, 25%, 50 and 75%) of Leucaena leucocephala foliage (LLF) in a completely randomized design. Results showed that sugarcane tops (SCT) ...

  18. Scattering of a TEM wave from a time varying surface

    Science.gov (United States)

    Elcrat, Alan R.; Harder, T. Mark; Stonebraker, John T.

    1990-03-01

    A solution is given for reflection of a plane wave with TEM polarization from a planar surface with time varying properties. These properties are given in terms of the currents on the surface. The solution is obtained by numerically solving a system of differential-delay equations in the time domain.

  19. Adolescent Sexual Behaviors at Varying Levels of Substance Use Frequency

    Science.gov (United States)

    Floyd, Leah J.; Latimer, William

    2010-01-01

    Combining substance use and sex compounds the risk of contracting sexually transmitted diseases, including HIV. However, the association between substance use and sexual behaviors may vary by substance and sexual behavior. The current study sought to examine the relationship between alcohol and marijuana use frequency and specific sexual…

  20. Karlovy Varys linastub kaks Eesti filmi / Andris Feldmanis

    Index Scriptorium Estoniae

    Feldmanis, Andris, 1982-

    2007-01-01

    Ilmar Raagi mängufilm "Klass" osaleb 42. Karlovy Vary rahvusvahelise filmifestivali võistlusprogrammis "East of the West" ja Asko Kase lühimängufilm "Zen läbi prügi" on valitud festivali kõrvalprogrammi "Forum of Independents"

  1. Time-varying correlation and common structures in volatility

    NARCIS (Netherlands)

    Liu, Yang

    2016-01-01

    This thesis studies time series properties of the covariance structure of multivariate asset returns. First, the time-varying feature of correlation is investigated at the intraday level with a new correlation model incorporating the intraday correlation dynamics. Second, the thesis develops a

  2. microwave oven-induced decalcification at varying temperatures

    African Journals Online (AJOL)

    Uwaifoh

    2012-09-30

    Sep 30, 2012 ... This study was designed to evaluate the effect of decalcifying fluid types on bone tissue architecture and its staining properties following decalcification at varying temperatures. A decalcification methodology using Golding and. Stewards (GS) fluid, and Jenkings fluid (JK), and a modern household ...

  3. Contact Dynamics of EHL Contacts under Time Varying Conditions

    NARCIS (Netherlands)

    Venner, Cornelis H.; Popovici, G.; Wijnant, Ysbrand H.; Dalmaz, G.; Lubrecht, A.A.; Priest, M

    2004-01-01

    By means of numerical simulations of two situations with time varying operating conditions it is shown that the dynamic behaviour of Elasto-Hydrodynamically Lubricated contacts in terms of vibrations can be characterized as: Changes in the mutual approach lead to film thickness changes in the inlet

  4. Electricity Futures Prices : Time Varying Sensitivity to Fundamentals

    NARCIS (Netherlands)

    S-E. Fleten (Stein-Erik); R. Huisman (Ronald); M. Kilic (Mehtap); H.P.G. Pennings (Enrico); S. Westgaard (Sjur)

    2014-01-01

    textabstractThis paper provides insight in the time-varying relation between electricity futures prices and fundamentals in the form of prices of contracts for fossil fuels. As supply curves are not constant and different producers have different marginal costs of production, we argue that the

  5. Visualizing time-varying harmonics using filter banks

    NARCIS (Netherlands)

    Duque, C.A.; Da Silveira, P.M.; Ribeiro, P.F.

    2011-01-01

    Although it is well known that Fourier analysis is in reality only accurately applicable to steady state waveforms, it is a widely used tool to study and monitor time-varying signals, such as are commonplace in electrical power systems. The disadvantages of Fourier analysis, such as frequency

  6. Time-Varying Value of Energy Efficiency in Michigan

    Energy Technology Data Exchange (ETDEWEB)

    Mims, Natalie; Eckman, Tom; Schwartz, Lisa C.

    2018-04-02

    Quantifying the time-varying value of energy efficiency is necessary to properly account for all of its benefits and costs and to identify and implement efficiency resources that contribute to a low-cost, reliable electric system. Historically, most quantification of the benefits of efficiency has focused largely on the economic value of annual energy reduction. Due to the lack of statistically representative metered end-use load shape data in Michigan (i.e., the hourly or seasonal timing of electricity savings), the ability to confidently characterize the time-varying value of energy efficiency savings in the state, especially for weather-sensitive measures such as central air conditioning, is limited. Still, electric utilities in Michigan can take advantage of opportunities to incorporate the time-varying value of efficiency into their planning. For example, end-use load research and hourly valuation of efficiency savings can be used for a variety of electricity planning functions, including load forecasting, demand-side management and evaluation, capacity planning, long-term resource planning, renewable energy integration, assessing potential grid modernization investments, establishing rates and pricing, and customer service (KEMA 2012). In addition, accurately calculating the time-varying value of efficiency may help energy efficiency program administrators prioritize existing offerings, set incentive or rebate levels that reflect the full value of efficiency, and design new programs.

  7. The early evolution of stars and planets with varying mass

    International Nuclear Information System (INIS)

    Bhattacharjee, S.K.

    1980-09-01

    In this thesis some aspects of stellar and planetary evolution with varying mass are examined. It is divided into two sections. The first section deals with the evolution of stars in the pre-main-sequence phase with mass accretion while in the second section we discuss the spin angular momentum of the planets with mass loss. (author)

  8. Additional Surgery after Breast-Conserving Surgery Varies Widely

    Science.gov (United States)

    A study published in the Feb. 1, 2012, issue of JAMA found that the number of women who have one or more additional surgeries to remove suspected residual tumor tissue (re-excisions) following breast-conserving surgery (BCS) for breast cancer varies widely across surgeons and hospitals.

  9. Effect of varying concentrations of orally ingested glucose on platelet ...

    African Journals Online (AJOL)

    The physiologic basis of bleeding is a function of normal platelets and coagulation factors. This study is aimed at ascertaining the effect of varying concentrations of orally ingested glucose on platelet count and hemoglobin concentration during menstruation. Forty menstruating students between the ages of 18 and 25 from ...

  10. Ballistic performance of a Kevlar-29 woven fibre composite under varied temperatures

    Science.gov (United States)

    Soykasap, O.; Colakoglu, M.

    2010-05-01

    Armours are usually manufactured from polymer matrix composites and used for both military and non-military purposes in different seasons, climates, and regions. The mechanical properties of the composites depend on temperature, which also affects their ballistic characteristics. The armour is used to absorb the kinetic energy of a projectile without any major injury to a person. Therefore, besides a high strength and lightness, a high damping capacity is required to absorb the impact energy transferred by the projectile. The ballistic properties of a Kevlar 29/polyvinyl butyral composite are investigated under varied temperatures in this study. The elastic modulus of the composite is determined from the natural frequency of composite specimens at different temperatures by using a damping monitoring method. Then, the backside deformation of composite plates is analysed experimentally and numerically employing the finite-element program Abaqus. The experimental and numeric results obtained are in good agreement.

  11. A Combined Experimental and Computational Approach to Subject-Specific Analysis of Knee Joint Laxity

    Science.gov (United States)

    Harris, Michael D.; Cyr, Adam J.; Ali, Azhar A.; Fitzpatrick, Clare K.; Rullkoetter, Paul J.; Maletsky, Lorin P.; Shelburne, Kevin B.

    2016-01-01

    Modeling complex knee biomechanics is a continual challenge, which has resulted in many models of varying levels of quality, complexity, and validation. Beyond modeling healthy knees, accurately mimicking pathologic knee mechanics, such as after cruciate rupture or meniscectomy, is difficult. Experimental tests of knee laxity can provide important information about ligament engagement and overall contributions to knee stability for development of subject-specific models to accurately simulate knee motion and loading. Our objective was to provide combined experimental tests and finite-element (FE) models of natural knee laxity that are subject-specific, have one-to-one experiment to model calibration, simulate ligament engagement in agreement with literature, and are adaptable for a variety of biomechanical investigations (e.g., cartilage contact, ligament strain, in vivo kinematics). Calibration involved perturbing ligament stiffness, initial ligament strain, and attachment location until model-predicted kinematics and ligament engagement matched experimental reports. Errors between model-predicted and experimental kinematics averaged ligaments agreed with literature descriptions. These results demonstrate the ability of our constraint models to be customized for multiple individuals and simultaneously call attention to the need to verify that ligament engagement is in good general agreement with literature. To facilitate further investigations of subject-specific or population based knee joint biomechanics, data collected during the experimental and modeling phases of this study are available for download by the research community. PMID:27306137

  12. Autoregressive spatially varying coefficients model for predicting daily PM2.5 using VIIRS satellite AOT

    Science.gov (United States)

    Schliep, E. M.; Gelfand, A. E.; Holland, D. M.

    2015-12-01

    There is considerable demand for accurate air quality information in human health analyses. The sparsity of ground monitoring stations across the United States motivates the need for advanced statistical models to predict air quality metrics, such as PM2.5, at unobserved sites. Remote sensing technologies have the potential to expand our knowledge of PM2.5 spatial patterns beyond what we can predict from current PM2.5 monitoring networks. Data from satellites have an additional advantage in not requiring extensive emission inventories necessary for most atmospheric models that have been used in earlier data fusion models for air pollution. Statistical models combining monitoring station data with satellite-obtained aerosol optical thickness (AOT), also referred to as aerosol optical depth (AOD), have been proposed in the literature with varying levels of success in predicting PM2.5. The benefit of using AOT is that satellites provide complete gridded spatial coverage. However, the challenges involved with using it in fusion models are (1) the correlation between the two data sources varies both in time and in space, (2) the data sources are temporally and spatially misaligned, and (3) there is extensive missingness in the monitoring data and also in the satellite data due to cloud cover. We propose a hierarchical autoregressive spatially varying coefficients model to jointly model the two data sources, which addresses the foregoing challenges. Additionally, we offer formal model comparison for competing models in terms of model fit and out of sample prediction of PM2.5. The models are applied to daily observations of PM2.5 and AOT in the summer months of 2013 across the conterminous United States. Most notably, during this time period, we find small in-sample improvement incorporating AOT into our autoregressive model but little out-of-sample predictive improvement.

  13. Anthropocene Age Wicked Challenges

    DEFF Research Database (Denmark)

    Edgeman, Rick; Wu, Zhaohui

    2015-01-01

    weather events, drought, and desertification; threatened food supplies; water pollution, air pollution, and soil contamination; and the connection of these to disease, violence, and terrorism. Wicked challenges are discussed in relation to enterprise excellence, sustainability, resilience and robustness...

  14. Big data challenges

    DEFF Research Database (Denmark)

    Bachlechner, Daniel; Leimbach, Timo

    2016-01-01

    Although reports on big data success stories have been accumulating in the media, most organizations dealing with high-volume, high-velocity and high-variety information assets still face challenges. Only a thorough understanding of these challenges puts organizations into a position in which...... they can make an informed decision for or against big data, and, if the decision is positive, overcome the challenges smoothly. The combination of a series of interviews with leading experts from enterprises, associations and research institutions, and focused literature reviews allowed not only...... framework are also relevant. For large enterprises and startups specialized in big data, it is typically easier to overcome the challenges than it is for other enterprises and public administration bodies....

  15. Space Robotics Challenge

    Data.gov (United States)

    National Aeronautics and Space Administration — The Space Robotics Challenge seeks to infuse robot autonomy from the best and brightest research groups in the robotics community into NASA robots for future...

  16. The Electric Car Challenge.

    Science.gov (United States)

    Diehl, Brian E.

    1997-01-01

    Describes the Electric Car Challenge during which students applied methods of construction to build lightweight, strong vehicles that were powered by electricity. The activity required problem solving, sheet metal work, electricity, design, and construction skills. (JOW)

  17. Challenges to Public Health

    Indian Academy of Sciences (India)

    First page Back Continue Last page Graphics. Challenges to Public Health. Tracing of the infection. Isolation of patients to stop spread. Laboratory diagnosis. Hospitalization &Treatment. Stock pile & supply of drugs. Planning & mitigation. Information to public. Support to SEARO countries.

  18. Community Challenge Grantees

    Data.gov (United States)

    Department of Housing and Urban Development — HUD's Community Challenge Grants aim to reform and reduce barriers to achieving affordable, economically vital and sustainable communities. The funds are awarded to...

  19. Brazil World Cup Challenges

    Directory of Open Access Journals (Sweden)

    MANSUR, R.

    2012-12-01

    Full Text Available Overcoming the productivity challenge is the main benefit of the 2014 World Cup for Brazilian people. The sustainable development of our cultural tourism industry will catapult the new middle class growing up rate.

  20. The boomer challenge.

    Science.gov (United States)

    Barr, Paul

    2014-01-01

    Hospitals and the rest of health care will have to make some major adjustments to meet the needs of the aging baby boom generation. The first article in our year-long series inventories the many challenges that lie ahead.

  1. Overcoming Safeguards Challenges

    International Nuclear Information System (INIS)

    Henriques, Sasha

    2011-01-01

    The focus of the 2010 IAEA International Safeguards Symposium was how best, from a technical perspective, to prepare for future verification challenges during this time of change. By bringing together the leading experts in the field from across the world, this symposium provided an opportunity for stakeholders to explore possible solutions in support of the IAEA's nuclear verification mission, and to identify areas where the different stakeholders in the safeguards business can help address these challenges

  2. Challenges in obesity research

    OpenAIRE

    Palou, Andreu; Bonet, M. Luisa

    2013-01-01

    Obesity is the main nutritional problem and one of the most important health problems in developed societies. Central to the challenge of obesity prevention and management is a thoroughly understanding of its determinants. Multiple socio-cultural, socio-economic, behavioural and biological factors -often interrelated and many of them still unknown or poorly understood- can contribute to the establishment and perpetuation of obese phenotypes. Here, we address current research challenges regard...

  3. Thermal shock behaviour of different tungsten grades under varying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wirtz, Oliver Marius

    2012-07-19

    Thermonuclear fusion power plants are a promising option to ensure the energy supply for future generations, but in many fields of research enormous challenges have to be faced. A major step on the way to the prototype fusion reactor DEMO will be ITER which is build in Cadarache, southern France. One of the most critical issues is the field of in-vessel materials and components, in particular the plasma facing materials (PFM). PFMs that will be used in a device like ITER have to withstand severe environmental conditions in terms of steady state and transient thermal loads as well as high particle fluxes such as hydrogen, helium and neutrons. Candidate wall materials are beryllium, tungsten and carbon based materials like CFC (carbon fibre composite). Tungsten is the most promising material for an application in the divertor region with very severe loading conditions and it will most probably also be used as PFM for DEMO. Hence, this work focuses on the investigation of the thermal shock response of different tungsten grades in order to understand the damage mechanisms and to identify material parameters which influence this behaviour under ITER and DEMO relevant operation conditions. Therefore the microstructure and the mechanical and thermal properties of five industrially manufactured tungsten grades were characterised. All five tungsten grades were exposed to transient thermal events with very high power densities of up to 1.27 GWm{sup -2} at varying base temperatures between RT and 600 C in the electron beam device JUDITH 1. The pulse numbers were limited to a maximum of 1000 in order to avoid immoderate workload on the test facility and to have enough time to cover a wide range of loading conditions. The results of this damage mapping enable to define different damage and cracking thresholds for the investigated tungsten grades and to identify certain material parameters which influence the location of these thresholds and the distinction of the induced

  4. Thermal shock behaviour of different tungsten grades under varying conditions

    International Nuclear Information System (INIS)

    Wirtz, Oliver Marius

    2012-01-01

    Thermonuclear fusion power plants are a promising option to ensure the energy supply for future generations, but in many fields of research enormous challenges have to be faced. A major step on the way to the prototype fusion reactor DEMO will be ITER which is build in Cadarache, southern France. One of the most critical issues is the field of in-vessel materials and components, in particular the plasma facing materials (PFM). PFMs that will be used in a device like ITER have to withstand severe environmental conditions in terms of steady state and transient thermal loads as well as high particle fluxes such as hydrogen, helium and neutrons. Candidate wall materials are beryllium, tungsten and carbon based materials like CFC (carbon fibre composite). Tungsten is the most promising material for an application in the divertor region with very severe loading conditions and it will most probably also be used as PFM for DEMO. Hence, this work focuses on the investigation of the thermal shock response of different tungsten grades in order to understand the damage mechanisms and to identify material parameters which influence this behaviour under ITER and DEMO relevant operation conditions. Therefore the microstructure and the mechanical and thermal properties of five industrially manufactured tungsten grades were characterised. All five tungsten grades were exposed to transient thermal events with very high power densities of up to 1.27 GWm -2 at varying base temperatures between RT and 600 C in the electron beam device JUDITH 1. The pulse numbers were limited to a maximum of 1000 in order to avoid immoderate workload on the test facility and to have enough time to cover a wide range of loading conditions. The results of this damage mapping enable to define different damage and cracking thresholds for the investigated tungsten grades and to identify certain material parameters which influence the location of these thresholds and the distinction of the induced damages

  5. BENSC. Experimental reports 1994

    International Nuclear Information System (INIS)

    Kirschbaum, Y.; Gast, H.; Michaelsen, R.

    1995-05-01

    This volume contains the guest groups' experimental reports describing experimental work carried out on the Berlin Scattering Center in 1994. These experimental reports are intended as interim summaries. (HP)

  6. BENSC experimental reports 1993

    International Nuclear Information System (INIS)

    Kirschbaum, Y.; Michaelsen, R.

    1994-05-01

    This volume contains the guest groups' experimental reports describing experimental work carried out on the Berlin Scattering Center in 1993. These experimental reports are intended as interim summaries. (HP)

  7. 77 FR 70835 - Centennial Challenges 2013 Sample Return Robot Challenge

    Science.gov (United States)

    2012-11-27

    ... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Centennial Challenges 2013 Sample Return Robot... Challenge is scheduled and teams that wish to compete may register. Centennial Challenges is a program of... Challenge, please visit: http://challenge.wpi.edu . For general information on the NASA Centennial...

  8. 76 FR 56819 - Centennial Challenges 2012 Sample Return Robot Challenge

    Science.gov (United States)

    2011-09-14

    ... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice (11-079)] Centennial Challenges 2012 Sample... Challenge is scheduled and teams that wish to compete may register. Centennial Challenges is a program of... Challenge, please visit: http://wp.wpi.edu/challenge/ . For general information on the NASA Centennial...

  9. Experimental constraints on transport

    International Nuclear Information System (INIS)

    Luce, T.C.; Petty, K.H.; Burrell, K.H.; Forest, C.B.; Gohil, P.; Groebner, R.J.; De Haas, J.C.M.; James, R.A.; Makowski, M.A.

    1994-12-01

    Characterization of the cross-field energy transport in magnetic confinement experiments in a manner applicable to the accurate assessment of future machine performance continues to be a challenging goal. Experimental results from the DIII-D tokamak in the areas of dimensionless scaling and non-diffusive transport represent progress toward this goal. Dimensionless scaling shows how beneficial the increase in machine size and magnetic field is for future devices. The experiments on DIII-D are the first to determine separately the electron and ion scaling with normalized gyroradius ρ * ; the electrons scale as expected from gyro-Bohm class theories, while the ions scale consistent with the Goldston empirical scaling. This result predicts an increase in transport relative to Bohm diffusion as ρ * decreases in future devices. The existence of distinct ρ * scalings for ions and electrons cautions against a physical interpretation of one-fluid or global analysis. The second class of experiments reported here are the first to demonstrate the existence of non-diffusive energy transport. Electron cyclotron heating was applied at the half radius; the electron temperature profile remains substantially peaked. Power balance analysis indicates that heat must flow in the direction of increasing temperature, which is inconsistent with purely diffusive transport. The dynamics of electron temperature perturbations indicate the presence in the heat flux of a term dependent on temperature rather than its gradient. These two observations strongly constrain the types of models which can be applied to cross-field heat transport

  10. Challenges in Double Beta Decay

    Directory of Open Access Journals (Sweden)

    Oliviero Cremonesi

    2014-01-01

    Full Text Available In the past ten years, neutrino oscillation experiments have provided the incontrovertible evidence that neutrinos mix and have finite masses. These results represent the strongest demonstration that the electroweak Standard Model is incomplete and that new Physics beyond it must exist. In this scenario, a unique role is played by the Neutrinoless Double Beta Decay searches which can probe lepton number conservation and investigate the Dirac/Majorana nature of the neutrinos and their absolute mass scale (hierarchy problem with unprecedented sensitivity. Today Neutrinoless Double Beta Decay faces a new era where large-scale experiments with a sensitivity approaching the so-called degenerate-hierarchy region are nearly ready to start and where the challenge for the next future is the construction of detectors characterized by a tonne-scale size and an incredibly low background. A number of new proposed projects took up this challenge. These are based either on large expansions of the present experiments or on new ideas to improve the technical performance and/or reduce the background contributions. In this paper, a review of the most relevant ongoing experiments is given. The most relevant parameters contributing to the experimental sensitivity are discussed and a critical comparison of the future projects is proposed.

  11. Time-varying properties of renal autoregulatory mechanisms

    DEFF Research Database (Denmark)

    Zou, Rui; Cupples, Will A; Yip, K P

    2002-01-01

    In order to assess the possible time-varying properties of renal autoregulation, time-frequency and time-scaling methods were applied to renal blood flow under broad-band forced arterial blood pressure fluctuations and single-nephron renal blood flow with spontaneous oscillations obtained from...... normotensive (Sprague-Dawley, Wistar, and Long-Evans) rats, and spontaneously hypertensive rats. Time-frequency analyses of normotensive and hypertensive blood flow data obtained from either the whole kidney or the single-nephron show that indeed both the myogenic and tubuloglomerular feedback (TGF) mechanisms...... have time-varying characteristics. Furthermore, we utilized the Renyi entropy to measure the complexity of blood-flow dynamics in the time-frequency plane in an effort to discern differences between normotensive and hypertensive recordings. We found a clear difference in Renyi entropy between...

  12. Performance of Traffic Noise Barriers with Varying Cross-Section

    Directory of Open Access Journals (Sweden)

    Sanja Grubeša

    2011-05-01

    Full Text Available The efficiency of noise barriers largely depends on their geometry. In this paper, the performance of noise barriers was simulated using the numerical Boundary Element Method (BEM. Traffic noise was particularly considered with its standardized noise spectrum adapted to human hearing. The cross-section of the barriers was varied with the goal of finding the optimum shape in comparison to classical rectangular barriers. The barrier performance was calculated at different receiver points for a fixed barrier height and source position. The magnitude of the insertion loss parameter was used to evaluate the performance change, both in one-third octave bands and as the broadband mean insertion loss value. The proposed barriers of varying cross-section were also compared with a typical T-shape barrier of the same height.

  13. Electron dynamics in solid state via time varying wavevectors

    Science.gov (United States)

    Khaneja, Navin

    2018-06-01

    In this paper, we study electron wavepacket dynamics in electric and magnetic fields. We rigorously derive the semiclassical equations of electron dynamics in electric and magnetic fields. We do it both for free electron and electron in a periodic potential. We do this by introducing time varying wavevectors k(t). In the presence of magnetic field, our wavepacket reproduces the classical cyclotron orbits once the origin of the Schröedinger equation is correctly chosen to be center of cyclotron orbit. In the presence of both electric and magnetic fields, our equations for wavepacket dynamics differ from classical Lorentz force equations. We show that in a periodic potential, on application of electric field, the electron wave function adiabatically follows the wavefunction of a time varying Bloch wavevector k(t), with its energies suitably shifted with time. We derive the effective mass equation and discuss conduction in conductors and insulators.

  14. Control of Linear Parameter Varying Systems with Applications

    CERN Document Server

    Mohammadpour, Javad

    2012-01-01

    Control of Linear Parameter Varying Systems with Applications compiles state-of-the-art contributions on novel analytical and computational methods to address system modeling and identification, complexity reduction, performance analysis and control design for time-varying and nonlinear systems in the LPV framework. The book has an interdisciplinary character by emphasizing techniques that can be commonly applied in various engineering fields. It also includes a rich collection of illustrative applications in diverse domains to substantiate the effectiveness of the design methodologies and provide pointers to open research directions. The book is divided into three parts. The first part collects chapters of a more tutorial character on the background of LPV systems modeling and control. The second part gathers chapters devoted to the theoretical advancement of LPV analysis and synthesis methods to cope with the design constraints such as uncertainties and time delay. The third part of the volume showcases con...

  15. Time varying determinants of bond flows to emerging markets

    Directory of Open Access Journals (Sweden)

    Yasemin Erduman

    2016-06-01

    Full Text Available This paper investigates the time varying nature of the determinants of bond flows with a focus on the global financial crisis period. We estimate a time varying regression model using Bayesian estimation methods, where the posterior distribution is approximated by Gibbs sampling algorithm. Our findings suggest that the interest rate differential is the most significant pull factor of portfolio bond flows, along with the inflation rate, while the growth rate does not play a significant role. Among the push factors, global liquidity is the most important driver of bond flows. It matters the most, when unconventional monetary easing policies were first announced; and its importance as a determinant of portfolio bond flows decreases over time, starting with the Eurozone crisis, and diminishes with the tapering talk. Global risk appetite and the risk perception towards the emerging countries also have relatively small and stable significant effects on bond flows.

  16. Λ( t ) cosmology induced by a slowly varying Elko field

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, S.H.; Pinho, A.S.S.; Silva, J.M. Hoff da [Universidade Estadual Paulista (Unesp), Faculdade de Engenharia, Guaratinguetá, Departamento de Física e Química Av. Dr. Ariberto Pereira da Cunha 333, 12516-410—Guaratinguetá, SP (Brazil); Jesus, J.F., E-mail: shpereira@feg.unesp.br, E-mail: alexandre.pinho510@gmail.com, E-mail: hoff@feg.unesp.br, E-mail: jfjesus@itapeva.unesp.br [Universidade Estadual Paulista (Unesp), Campus Experimental de Itapeva, R. Geraldo Alckmin, 519 Itapeva, SP (Brazil)

    2017-01-01

    In this work the exact Friedmann-Robertson-Walker equations for an Elko spinor field coupled to gravity in an Einstein-Cartan framework are presented. The torsion functions coupling the Elko field spin-connection to gravity can be exactly solved and the FRW equations for the system assume a relatively simple form. In the limit of a slowly varying Elko spinor field there is a relevant contribution to the field equations acting exactly as a time varying cosmological model Λ( t )=Λ{sub *}+3β H {sup 2}, where Λ{sub *} and β are constants. Observational data using distance luminosity from magnitudes of supernovae constraint the parameters Ω {sub m} and β, which leads to a lower limit to the Elko mass. Such model mimics, then, the effects of a dark energy fluid, here sourced by the Elko spinor field. The density perturbations in the linear regime were also studied in the pseudo-Newtonian formalism.

  17. Modelling Time-Varying Volatility in Financial Returns

    DEFF Research Database (Denmark)

    Amado, Cristina; Laakkonen, Helinä

    2014-01-01

    The “unusually uncertain” phase in the global financial markets has inspired many researchers to study the effects of ambiguity (or “Knightian uncertainty”) on the decisions made by investors and their implications for the capital markets. We contribute to this literature by using a modified...... version of the time-varying GARCH model of Amado and Teräsvirta (2013) to analyze whether the increasing uncertainty has caused excess volatility in the US and European government bond markets. In our model, volatility is multiplicatively decomposed into two time-varying conditional components: the first...... being captured by a stable GARCH(1,1) process and the second driven by the level of uncertainty in the financial market....

  18. Non-minimally coupled varying constants quantum cosmologies

    International Nuclear Information System (INIS)

    Balcerzak, Adam

    2015-01-01

    We consider gravity theory with varying speed of light and varying gravitational constant. Both constants are represented by non-minimally coupled scalar fields. We examine the cosmological evolution in the near curvature singularity regime. We find that at the curvature singularity the speed of light goes to infinity while the gravitational constant vanishes. This corresponds to the Newton's Mechanics limit represented by one of the vertex of the Bronshtein-Zelmanov-Okun cube [1,2]. The cosmological evolution includes both the pre-big-bang and post-big-bang phases separated by the curvature singularity. We also investigate the quantum counterpart of the considered theory and find the probability of transition of the universe from the collapsing pre-big-bang phase to the expanding post-big-bang phase

  19. Epidemic spread in coupled populations with seasonally varying migration rates

    Science.gov (United States)

    Muzyczyn, Adam; Shaw, Leah B.

    2009-03-01

    The H5N1 strain of avian influenza has spread worldwide, and this spread may be due to seasonal migration of birds and mixing of birds from different regions in the wintering grounds. We studied a multipatch model for avian influenza with seasonally varying migration rates. The bird population was divided into two spatially distinct patches, or subpopulations. Within each patch, the disease followed the SIR (susceptible-infected-recovered) model for epidemic spread. Migration rates were varied periodically, with a net flux toward the breeding grounds during the spring and towards the wintering grounds during the fall. The case of two symmetric patches reduced to single-patch SIR dynamics. However, asymmetry in the birth and contact rates in the breeding grounds and wintering grounds led to bifurcations to longer period orbits and chaotic dynamics. We studied the bifurcation structure of the model and the phase relationships between outbreaks in the two patches.

  20. Scaling properties in time-varying networks with memory

    Science.gov (United States)

    Kim, Hyewon; Ha, Meesoon; Jeong, Hawoong

    2015-12-01

    The formation of network structure is mainly influenced by an individual node's activity and its memory, where activity can usually be interpreted as the individual inherent property and memory can be represented by the interaction strength between nodes. In our study, we define the activity through the appearance pattern in the time-aggregated network representation, and quantify the memory through the contact pattern of empirical temporal networks. To address the role of activity and memory in epidemics on time-varying networks, we propose temporal-pattern coarsening of activity-driven growing networks with memory. In particular, we focus on the relation between time-scale coarsening and spreading dynamics in the context of dynamic scaling and finite-size scaling. Finally, we discuss the universality issue of spreading dynamics on time-varying networks for various memory-causality tests.

  1. Local Feature Learning for Face Recognition under Varying Poses

    DEFF Research Database (Denmark)

    Duan, Xiaodong; Tan, Zheng-Hua

    2015-01-01

    In this paper, we present a local feature learning method for face recognition to deal with varying poses. As opposed to the commonly used approaches of recovering frontal face images from profile views, the proposed method extracts the subject related part from a local feature by removing the pose...... related part in it on the basis of a pose feature. The method has a closed-form solution, hence being time efficient. For performance evaluation, cross pose face recognition experiments are conducted on two public face recognition databases FERET and FEI. The proposed method shows a significant...... recognition improvement under varying poses over general local feature approaches and outperforms or is comparable with related state-of-the-art pose invariant face recognition approaches. Copyright ©2015 by IEEE....

  2. Nonlinear systems time-varying parameter estimation: Application to induction motors

    Energy Technology Data Exchange (ETDEWEB)

    Kenne, Godpromesse [Laboratoire d' Automatique et d' Informatique Appliquee (LAIA), Departement de Genie Electrique, IUT FOTSO Victor, Universite de Dschang, B.P. 134 Bandjoun (Cameroon); Ahmed-Ali, Tarek [Ecole Nationale Superieure des Ingenieurs des Etudes et Techniques d' Armement (ENSIETA), 2 Rue Francois Verny, 29806 Brest Cedex 9 (France); Lamnabhi-Lagarrigue, F. [Laboratoire des Signaux et Systemes (L2S), C.N.R.S-SUPELEC, Universite Paris XI, 3 Rue Joliot Curie, 91192 Gif-sur-Yvette (France); Arzande, Amir [Departement Energie, Ecole Superieure d' Electricite-SUPELEC, 3 Rue Joliot Curie, 91192 Gif-sur-Yvette (France)

    2008-11-15

    In this paper, an algorithm for time-varying parameter estimation for a large class of nonlinear systems is presented. The proof of the convergence of the estimates to their true values is achieved using Lyapunov theories and does not require that the classical persistent excitation condition be satisfied by the input signal. Since the induction motor (IM) is widely used in several industrial sectors, the algorithm developed is potentially useful for adjusting the controller parameters of variable speed drives. The method proposed is simple and easily implementable in real-time. The application of this approach to on-line estimation of the rotor resistance of IM shows a rapidly converging estimate in spite of measurement noise, discretization effects, parameter uncertainties (e.g. inaccuracies on motor inductance values) and modeling inaccuracies. The robustness analysis for this IM application also revealed that the proposed scheme is insensitive to the stator resistance variations within a wide range. The merits of the proposed algorithm in the case of on-line time-varying rotor resistance estimation are demonstrated via experimental results in various operating conditions of the induction motor. The experimental results obtained demonstrate that the application of the proposed algorithm to update on-line the parameters of an adaptive controller (e.g. IM and synchronous machines adaptive control) can improve the efficiency of the industrial process. The other interesting features of the proposed method include fault detection/estimation and adaptive control of IM and synchronous machines. (author)

  3. effect of gasket of varying thickness on spark ignition engines

    African Journals Online (AJOL)

    DJFLEX

    In the study of Toyota, In-line, 4 cylinders, spark ignition engine using gaskets of varying thicknesses. (1.75mm, 3.5mm, 5.25mm, 7mm and 8.75mm) between the cylinder head and the engine block, the performance characteristics of the engine was investigated via the effect of engine speed on brake power, brake thermal ...

  4. Housing Cycles in Switzerland - A Time-Varying Approach

    OpenAIRE

    Drechsel, Dirk

    2015-01-01

    In light of the strong increase of house prices in Switzerland, we analyze the effects of mortgage rate shocks, changes in the interplay between housing demand and supply and GDP growth on house prices for the time period 1981- 2014. We employ Bayesian time-varying coefficients vector autoregressions to allow different monetary and immigration regimes over time. A number of structural changes, such as regulatory changes in the aftermath of the 1990s real estate crisis, the introduction of fre...

  5. Method and apparatus of prefetching streams of varying prefetch depth

    Science.gov (United States)

    Gara, Alan [Mount Kisco, NY; Ohmacht, Martin [Yorktown Heights, NY; Salapura, Valentina [Chappaqua, NY; Sugavanam, Krishnan [Mahopac, NY; Hoenicke, Dirk [Seebruck-Seeon, DE

    2012-01-24

    Method and apparatus of prefetching streams of varying prefetch depth dynamically changes the depth of prefetching so that the number of multiple streams as well as the hit rate of a single stream are optimized. The method and apparatus in one aspect monitor a plurality of load requests from a processing unit for data in a prefetch buffer, determine an access pattern associated with the plurality of load requests and adjust a prefetch depth according to the access pattern.

  6. Tracking time-varying parameters with local regression

    DEFF Research Database (Denmark)

    Joensen, Alfred Karsten; Nielsen, Henrik Aalborg; Nielsen, Torben Skov

    2000-01-01

    This paper shows that the recursive least-squares (RLS) algorithm with forgetting factor is a special case of a varying-coe\\$cient model, and a model which can easily be estimated via simple local regression. This observation allows us to formulate a new method which retains the RLS algorithm, bu......, but extends the algorithm by including polynomial approximations. Simulation results are provided, which indicates that this new method is superior to the classical RLS method, if the parameter variations are smooth....

  7. Attitudes as Object-Evaluation Associations of Varying Strength

    OpenAIRE

    Fazio, Russell H.

    2007-01-01

    Historical developments regarding the attitude concept are reviewed, and set the stage for consideration of a theoretical perspective that views attitude, not as a hypothetical construct, but as evaluative knowledge. A model of attitudes as object-evaluation associations of varying strength is summarized, along with research supporting the model’s contention that at least some attitudes are represented in memory and activated automatically upon the individual’s encountering the attitude objec...

  8. Denitrification activity in mangrove sediments varies with associated vegetation

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, S.O.; Dutta, P.; Gonsalves, M.J.B.D.; Bonin, P.C.; LokaBharathi, P.A.

    . Eng.: 95; 2016; 671-681 Denitrification activity in mangrove sediments varies with associated vegetation Sheryl Oliveira Fernandes a, #, Pinky Dutta b, Maria-Judith Gonsalves a, Patricia C. Bonin c, P. A. LokaBharathi a, *  a Biological... in tropical and subtropical regions of the world (Giri et al., 2011). They provide a range of ecosystem services like soil formation, wood production, fish spawning grounds, carbon (C) storage and nutrient cycling (Murdiyarso et al., 2015). However, over...

  9. Does the availability of snack foods in supermarkets vary internationally?

    OpenAIRE

    Thornton, Lukar E; Cameron, Adrian J; McNaughton, Sarah A; Waterlander, Wilma E; Sodergren, Marita; Svastisalee, Chalida; Blanchard, Laurence; Liese, Angela D; Battersby, Sarah; Carter, Mary-Ann; Sheeshka, Judy; Kirkpatrick, Sharon I; Sherman, Sandy; Cowburn, Gill; Foster, Charlie

    2013-01-01

    Background Cross-country differences in dietary behaviours and obesity rates have been previously reported. Consumption of energy-dense snack foods and soft drinks are implicated as contributing to weight gain, however little is known about how the availability of these items within supermarkets varies internationally. This study assessed variations in the display of snack foods and soft drinks within a sample of supermarkets across eight countries. Methods Within-store audits were used to ev...

  10. Simple Model with Time-Varying Fine-Structure ``Constant''

    Science.gov (United States)

    Berman, M. S.

    2009-10-01

    Extending the original version written in colaboration with L.A. Trevisan, we study the generalisation of Dirac's LNH, so that time-variation of the fine-structure constant, due to varying electrical and magnetic permittivities is included along with other variations (cosmological and gravitational ``constants''), etc. We consider the present Universe, and also an inflationary scenario. Rotation of the Universe is a given possibility in this model.

  11. Influence of varying diets on radiosensitivity of quinea pigs

    International Nuclear Information System (INIS)

    Darenskaya, N.G.; Kuznetsova, S.S.; Lebengarts, Ya.Z.

    1975-01-01

    Seven groups of 25-day-old Guinea pig males given different diets during the entire observation period. Six groups received full-ration granulated mixed food varying in the contents of protein and cellulose, while the seventh group ate natural food. Experiments with irradiation failed to reveal any essential differences in radiosensitivity of animals grown on natural and mixed food, which enabled us to propose full-ration granulated mixed food for feeding laboratory guinea pigs

  12. Weakly Coupled Oscillators in a Slowly Varying World

    OpenAIRE

    Park, Youngmin; Ermentrout, Bard

    2016-01-01

    We extend the theory of weakly coupled oscillators to incorporate slowly varying inputs and parameters. We employ a combination of regular perturbation and an adiabatic approximation to derive equations for the phase-difference between a pair of oscillators. We apply this to the simple Hopf oscillator and then to a biophysical model. The latter represents the behavior of a neuron that is subject to slow modulation of a muscarinic current such as would occur during transient attention through ...

  13. Influence of varying diets on radiosensitivity of quinea pigs

    Energy Technology Data Exchange (ETDEWEB)

    Darenskaya, N G; Kuznetsova, S S; Lebengarts, Ya Z

    1975-07-01

    Seven groups of 25-day-old Guinea pig males given different diets during the entire observation period. Six groups received full-ration granulated mixed food varying in the contents of protein and cellulose, while the seventh group ate natural food. Experiments with irradiation failed to reveal any essential differences in radiosensitivity of animals grown on natural and mixed food, which enabled us to propose full-ration granulated mixed food for feeding laboratory guinea pigs.

  14. Phototrophic microvegetation of thermal springs in Karlovy Vary, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Kaštovský, J.; span class="emphasis">Komárek, Jiříspan>

    2001-01-01

    Roč. 123, - (2001), s. 107-120 ISSN 1438-9134. [International conference: Algae and extreme environments. Třeboň, 11.09.2000-16.09.2000] R&D Projects: GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z6005908 Keywords : Cyanobacteria * algae * biodiversity * thermal springs * Karlovy Vary Spa * ecology * seasonality * anthropogenic factors * conservation Subject RIV: EF - Botanics Impact factor: 0.488, year: 2000

  15. A reciprocal Wald theorem for varying gravitational function

    International Nuclear Information System (INIS)

    Fay, Stephane

    2004-01-01

    We study when a cosmological constant is a natural issue if it is mimicked by the potential of a massive Hyperextended Scalar Tensor theory with a perfect fluid for Bianchi type I and V models. We then deduce a reciprocal Wald theorem giving the conditions such that the potential tends to a non vanishing constant when the gravitational function varies. We also get the conditions allowing the potential to vanish or diverge. (orig.)

  16. Model Complexities of Shallow Networks Representing Highly Varying Functions

    Czech Academy of Sciences Publication Activity Database

    Kůrková, Věra; Sanguineti, M.

    2016-01-01

    Roč. 171, 1 January (2016), s. 598-604 ISSN 0925-2312 R&D Projects: GA MŠk(CZ) LD13002 Grant - others:grant for Visiting Professors(IT) GNAMPA-INdAM Institutional support: RVO:67985807 Keywords : shallow networks * model complexity * highly varying functions * Chernoff bound * perceptrons * Gaussian kernel units Subject RIV: IN - Informatics, Computer Science Impact factor: 3.317, year: 2016

  17. Modeling information diffusion in time-varying community networks

    Science.gov (United States)

    Cui, Xuelian; Zhao, Narisa

    2017-12-01

    Social networks are rarely static, and they typically have time-varying network topologies. A great number of studies have modeled temporal networks and explored social contagion processes within these models; however, few of these studies have considered community structure variations. In this paper, we present a study of how the time-varying property of a modular structure influences the information dissemination. First, we propose a continuous-time Markov model of information diffusion where two parameters, mobility rate and community attractiveness, are introduced to address the time-varying nature of the community structure. The basic reproduction number is derived, and the accuracy of this model is evaluated by comparing the simulation and theoretical results. Furthermore, numerical results illustrate that generally both the mobility rate and community attractiveness significantly promote the information diffusion process, especially in the initial outbreak stage. Moreover, the strength of this promotion effect is much stronger when the modularity is higher. Counterintuitively, it is found that when all communities have the same attractiveness, social mobility no longer accelerates the diffusion process. In addition, we show that the local spreading in the advantage group has been greatly enhanced due to the agglomeration effect caused by the social mobility and community attractiveness difference, which thus increases the global spreading.

  18. VariVis: a visualisation toolkit for variation databases

    Directory of Open Access Journals (Sweden)

    Smith Timothy D

    2008-04-01

    Full Text Available Abstract Background With the completion of the Human Genome Project and recent advancements in mutation detection technologies, the volume of data available on genetic variations has risen considerably. These data are stored in online variation databases and provide important clues to the cause of diseases and potential side effects or resistance to drugs. However, the data presentation techniques employed by most of these databases make them difficult to use and understand. Results Here we present a visualisation toolkit that can be employed by online variation databases to generate graphical models of gene sequence with corresponding variations and their consequences. The VariVis software package can run on any web server capable of executing Perl CGI scripts and can interface with numerous Database Management Systems and "flat-file" data files. VariVis produces two easily understandable graphical depictions of any gene sequence and matches these with variant data. While developed with the goal of improving the utility of human variation databases, the VariVis package can be used in any variation database to enhance utilisation of, and access to, critical information.

  19. Time-varying linear control for tiltrotor aircraft

    Directory of Open Access Journals (Sweden)

    Jing ZHANG

    2018-04-01

    Full Text Available Tiltrotor aircraft have three flight modes: helicopter mode, airplane mode, and transition mode. A tiltrotor has characteristics of highly nonlinear, time-varying flight dynamics and inertial/control couplings in its transition mode. It can transit from the helicopter mode to the airplane mode by tilting its nacelles, and an effective controller is crucial to accomplish tilting transition missions. Longitudinal dynamic characteristics of the tiltrotor are described by a nonlinear Lagrange-form model, which takes into account inertial/control couplings and aerodynamic interferences. Reference commands for airspeed velocity and attitude in the transition mode are calculated dynamically by visiting a command library which is founded in advance by analyzing the flight envelope of the tiltrotor. A Time-Varying Linear (TVL model is obtained using a Taylor-expansion based online linearization technique from the nonlinear model. Subsequently, based on an optimal control concept, an online optimization based control method with input constraints considered is proposed. To validate the proposed control method, three typical tilting transition missions are simulated using the nonlinear model of XV-15 tiltrotor aircraft. Simulation results show that the controller can be used to control the tiltrotor throughout its operating envelop which includes a transition flight, and can also deal with vertical gust disturbances. Keywords: Constrained optimal control, Inertia/control couplings, Tiltrotor aircraft, Time-varying control, Transition mode

  20. Radiation damage in stainless steel under varying temperature neutron irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Naoaki [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1998-03-01

    Microstructural evolution of model alloys of 316SS was examined by neutron irradiation at JMTR under cyclic temperature varying condition. In the case of Fe-16Cr-17Ni, formation of interstitial loops and voids are strongly suppressed by varying the temperature from 473K to 673K. By adding Ti as miner element (0.25wt%), however, abnormal accumulation of vacancies (void swelling of 11%dpa at 0.1dpa) was observed. Theoretical analysis standing on the rate theory of defect clustering and simulation irradiation experiments with heavy ions indicates that the vacancy-rich condition which appears temporally during and after changing the temperature from low to high brings these results. It was also shown that only 1 dpa pre-irradiation at low temperature changes swelling behavior at high temperature above several 10 dpa. The understanding of non-steady-state defect processes under temperature varying irradiation is very important to estimate the radiation damage under fusion environment where short-term and long-term temperature variation is expected. (author)

  1. Shape and Spatially-Varying Reflectance Estimation from Virtual Exemplars.

    Science.gov (United States)

    Hui, Zhuo; Sankaranarayanan, Aswin C

    2017-10-01

    This paper addresses the problem of estimating the shape of objects that exhibit spatially-varying reflectance. We assume that multiple images of the object are obtained under a fixed view-point and varying illumination, i.e., the setting of photometric stereo. At the core of our techniques is the assumption that the BRDF at each pixel lies in the non-negative span of a known BRDF dictionary. This assumption enables a per-pixel surface normal and BRDF estimation framework that is computationally tractable and requires no initialization in spite of the underlying problem being non-convex. Our estimation framework first solves for the surface normal at each pixel using a variant of example-based photometric stereo. We design an efficient multi-scale search strategy for estimating the surface normal and subsequently, refine this estimate using a gradient descent procedure. Given the surface normal estimate, we solve for the spatially-varying BRDF by constraining the BRDF at each pixel to be in the span of the BRDF dictionary; here, we use additional priors to further regularize the solution. A hallmark of our approach is that it does not require iterative optimization techniques nor the need for careful initialization, both of which are endemic to most state-of-the-art techniques. We showcase the performance of our technique on a wide range of simulated and real scenes where we outperform competing methods.

  2. Challenges in obesity research.

    Science.gov (United States)

    Palou, Andreu; Bonet, M Luisa

    2013-09-01

    Obesity is the main nutritional problem and one of the most important health problems in developed societies. Central to the challenge of obesity prevention and management is a thoroughly understanding of its determinants. Multiple socio-cultural, socio-economic, behavioural and biological factors--often interrelated and many of them still unknown or poorly understood--can contribute to the establishment and perpetuation of obese phenotypes. Here, we address current research challenges regarding basic aspects of obesity and emerging science for its control, including brown adipose tissue thermogenesis and browning of white fat as possible therapeutic targets for obesity, the influence of the microbioma, and genetics, epigenetics, nutrigenomics and nutrigenetics of obesity. We also highlight hot topics in relation to food and lifestyle as determinants of obesity, including the brain mechanisms underlying environmental motivation to eat, the biological control of spontaneous physical activity, the possible role of concrete foods and food components, and the importance of early life nutrition and environment. Challenges regarding the connections of obesity with other alterations and pathologies are also briefly addressed, as well as social and economical challenges in relation to healthy food production and lifestyle for the prevention of obesity, and technological challenges in obesity research and management. The objective is to give a panoramic of advances accomplished and still ahead relevant to the different stakeholders engaged in understanding and combating obesity. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

  3. Consumer flexibility - State and challenges

    International Nuclear Information System (INIS)

    Grande, Ove S.; Saele, Hanne; Morch, Andrei Z.

    2002-02-01

    This report summarises experiences and results from relevant projects carried out within the area of consumer flexibility in the last years. A general description of the projects is presented. In addition are testing activities, economical signals for motivating the end user for load reductions and appropriate technology for communication and effect management mentioned separately. Briefly summarised is the following achieved: 1) The potential for effect regulating measures in ordinary consumption and in power demanding industry is analysed and estimated to 1750 MW and 3360 MW respectively. 2) Time varied rates are developed and are tested. The NVE has decided on this basis that all the network owners should offer season varied rates to their customers. 3) Test projects in Drammen, Oslo and Trondheim have shown that it is possible to motivate smaller consumers for and implement load reductions. 4) Technology for load management for the end user is evaluated. 5) A survey is made viewing the technology for two way communication. In addition the ''option'' market for the reserves of the Statnett has proved that a steady compensation is a sufficient incentive for producing substantial effect reserves in the load sector (power intensive industry). In the last part of the report the incentives and frame conditions for establishing technical solutions and infrastructure are discussed. Further work will focus on the consumer flexibility in shortage situations. The main challenges are connected to: 1) Establishing a foundation for decisions concerning cost efficient investments in necessary technical equipment. 2) To find an optimal combination of a price flexible and remote controlled load reduction

  4. An Inexpensive, Stable, and Accurate Relative Humidity Measurement Method for Challenging Environments.

    Science.gov (United States)

    Zhang, Wei; Ma, Hong; Yang, Simon X

    2016-03-18

    In this research, an improved psychrometer is developed to solve practical issues arising in the relative humidity measurement of challenging drying environments for meat manufacturing in agricultural and agri-food industries. The design in this research focused on the structure of the improved psychrometer, signal conversion, and calculation methods. The experimental results showed the effect of varying psychrometer structure on relative humidity measurement accuracy. An industrial application to dry-cured meat products demonstrated the effective performance of the improved psychrometer being used as a relative humidity measurement sensor in meat-drying rooms. In a drying environment for meat manufacturing, the achieved measurement accuracy for relative humidity using the improved psychrometer was ±0.6%. The system test results showed that the improved psychrometer can provide reliable and long-term stable relative humidity measurements with high accuracy in the drying system of meat products.

  5. Experimental Investigation of Flow Condensation in Microgravity

    Science.gov (United States)

    Lee, Hyoungsoon; Park, Ilchung; Konishi, Christopher; Mudawar, Issam; May, Rochelle I.; Juergens, Jeffery R.; Wagner, James D.; Hall, Nancy R.; Nahra, Henry K.; Hasan, Mohammed M.; hide

    2013-01-01

    Future manned missions to Mars are expected to greatly increase the space vehicle's size, weight, and heat dissipation requirements. An effective means to reducing both size and weight is to replace single-phase thermal management systems with two-phase counterparts that capitalize upon both latent and sensible heat of the coolant rather than sensible heat alone. This shift is expected to yield orders of magnitude enhancements in flow boiling and condensation heat transfer coefficients. A major challenge to this shift is a lack of reliable tools for accurate prediction of two-phase pressure drop and heat transfer coefficient in reduced gravity. Developing such tools will require a sophisticated experimental facility to enable investigators to perform both flow boiling and condensation experiments in microgravity in pursuit of reliable databases. This study will discuss the development of the Flow Boiling and Condensation Experiment (FBCE) for the International Space Station (ISS), which was initiated in 2012 in collaboration between Purdue University and NASA Glenn Research Center. This facility was recently tested in parabolic flight to acquire condensation data for FC-72 in microgravity, aided by high-speed video analysis of interfacial structure of the condensation film. The condensation is achieved by rejecting heat to a counter flow of water, and experiments were performed at different mass velocities of FC-72 and water and different FC-72 inlet qualities. It is shown that the film flow varies from smooth-laminar to wavy-laminar and ultimately turbulent with increasing FC-72 mass velocity. The heat transfer coefficient is highest near the inlet of the condensation tube, where the film is thinnest, and decreases monotonically along the tube, except for high FC-72 mass velocities, where the heat transfer coefficient is enhanced downstream. This enhancement is attributed to both turbulence and increased interfacial waviness. One-ge correlations are shown to

  6. Varying hemin concentrations affect Porphyromonas gingivalis strains differently.

    Science.gov (United States)

    Ohya, Manabu; Cueno, Marni E; Tamura, Muneaki; Ochiai, Kuniyasu

    2016-05-01

    Porphyromonas gingivalis requires heme to grow, however, heme availability and concentration in the periodontal pockets vary. Fluctuations in heme concentration may affect each P. gingivalis strain differently, however, this was never fully demonstrated. Here, we elucidated the effects of varying hemin concentrations in representative P. gingivalis strains. Throughout this study, representative P. gingivalis strains [FDC381 (type I), MPWIb-01 (type Ib), TDC60 (type II), ATCC49417 (type III), W83 (type IV), and HNA99 (type V)] were used and grown for 24 h in growth media under varying hemin concentrations (5 × , 1 × , 0.5 × , 0.1 × ). Samples were lysed and protein standardized. Arg-gingipain (Rgp), H2O2, and superoxide dismutase (SOD) levels were subsequently measured. We focused our study on 24 h-grown strains which excluded MPWIb-01 and HNA99. Rgp activity among the 4 remaining strains varied with Rgp peaking at: 1 × for FDC381, 5 × for TDC60, 0.5 × for ATCC49417, 5 × and 0.5 × for W83. With regards to H2O2 and SOD amounts: FDC381 had similar H2O2 amounts in all hemin concentrations while SOD levels varied; TDC60 had the lowest H2O2 amount at 1 × while SOD levels became higher in relation to hemin concentration; ATCC49417 also had similar H2O2 amounts in all hemin concentrations while SOD levels were higher at 1 × and 0.5 × ; and W83 had statistically similar H2O2 and SOD amounts regardless of hemin concentration. Our results show that variations in hemin concentration affect each P. gingivalis strain differently. Published by Elsevier Ltd.

  7. Identification of Affine Linear Parameter Varying Models for Adaptive Interventions in Fibromyalgia Treatment.

    Science.gov (United States)

    Dos Santos, P Lopes; Deshpande, Sunil; Rivera, Daniel E; Azevedo-Perdicoúlis, T-P; Ramos, J A; Younger, Jarred

    2013-12-31

    There is good evidence that naltrexone, an opioid antagonist, has a strong neuroprotective role and may be a potential drug for the treatment of fibromyalgia. In previous work, some of the authors used experimental clinical data to identify input-output linear time invariant models that were used to extract useful information about the effect of this drug on fibromyalgia symptoms. Additional factors such as anxiety, stress, mood, and headache, were considered as additive disturbances. However, it seems reasonable to think that these factors do not affect the drug actuation, but only the way in which a participant perceives how the drug actuates on herself. Under this hypothesis the linear time invariant models can be replaced by State-Space Affine Linear Parameter Varying models where the disturbances are seen as a scheduling signal signal only acting at the parameters of the output equation. In this paper a new algorithm for identifying such a model is proposed. This algorithm minimizes a quadratic criterion of the output error. Since the output error is a linear function of some parameters, the Affine Linear Parameter Varying system identification is formulated as a separable nonlinear least squares problem. Likewise other identification algorithms using gradient optimization methods several parameter derivatives are dynamical systems that must be simulated. In order to increase time efficiency a canonical parametrization that minimizes the number of systems to be simulated is chosen. The effectiveness of the algorithm is assessed in a case study where an Affine Parameter Varying Model is identified from the experimental data used in the previous study and compared with the time-invariant model.

  8. Sedimentary Geology Context and Challenges for Cyberinfrastructure Data Management

    Science.gov (United States)

    Chan, M. A.; Budd, D. A.

    2014-12-01

    A cyberinfrastructure data management system for sedimentary geology is crucial to multiple facets of interdisciplinary Earth science research, as sedimentary systems form the deep-time framework for many geoscience communities. The breadth and depth of the sedimentary field spans research on the processes that form, shape and affect the Earth's sedimentary crust and distribute resources such as hydrocarbons, coal, and water. The sedimentary record is used by Earth scientists to explore questions such as the continental crust evolution, dynamics of Earth's past climates and oceans, evolution of the biosphere, and the human interface with Earth surface processes. Major challenges to a data management system for sedimentary geology are the volume and diversity of field, analytical, and experimental data, along with many types of physical objects. Objects include rock samples, biological specimens, cores, and photographs. Field data runs the gamut from discrete location and spatial orientation to vertical records of bed thickness, textures, color, sedimentary structures, and grain types. Ex situ information can include geochemistry, mineralogy, petrophysics, chronologic, and paleobiologic data. All data types cover multiple order-of-magnitude scales, often requiring correlation of the multiple scales with varying degrees of resolution. The stratigraphic framework needs dimensional context with locality, time, space, and depth relationships. A significant challenge is that physical objects represent discrete values at specific points, but measured stratigraphic sections are continuous. In many cases, field data is not easily quantified, and determining uncertainty can be difficult. Despite many possible hurdles, the sedimentary community is anxious to embrace geoinformatic resources that can provide better tools to integrate the many data types, create better search capabilities, and equip our communities to conduct high-impact science at unprecedented levels.

  9. Time-varying value of electric energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Mims, Natalie A.; Eckman, Tom; Goldman, Charles

    2017-06-30

    Electric energy efficiency resources save energy and may reduce peak demand. Historically, quantification of energy efficiency benefits has largely focused on the economic value of energy savings during the first year and lifetime of the installed measures. Due in part to the lack of publicly available research on end-use load shapes (i.e., the hourly or seasonal timing of electricity savings) and energy savings shapes, consideration of the impact of energy efficiency on peak demand reduction (i.e., capacity savings) has been more limited. End-use load research and the hourly valuation of efficiency savings are used for a variety of electricity planning functions, including load forecasting, demand-side management and evaluation, capacity and demand response planning, long-term resource planning, renewable energy integration, assessing potential grid modernization investments, establishing rates and pricing, and customer service. This study reviews existing literature on the time-varying value of energy efficiency savings, provides examples in four geographically diverse locations of how consideration of the time-varying value of efficiency savings impacts the calculation of power system benefits, and identifies future research needs to enhance the consideration of the time-varying value of energy efficiency in cost-effectiveness screening analysis. Findings from this study include: -The time-varying value of individual energy efficiency measures varies across the locations studied because of the physical and operational characteristics of the individual utility system (e.g., summer or winter peaking, load factor, reserve margin) as well as the time periods during which savings from measures occur. -Across the four locations studied, some of the largest capacity benefits from energy efficiency are derived from the deferral of transmission and distribution system infrastructure upgrades. However, the deferred cost of such upgrades also exhibited the greatest range

  10. Global challenges in energy

    International Nuclear Information System (INIS)

    Dorian, James P.; Franssen, Herman T.; Simbeck, Dale R. MD

    2006-01-01

    Environmental and security concerns are stimulating global interest in hydrogen power, renewable energy, and advanced transportation technologies, but no significant movement away from oil and a carbon-based world economy is expected soon. Over the longer-term, however, a transition from fossil fuels to a non-carbon-based economy will likely occur, affecting the type of environment future generations may encounter. Key challenges will face the world's energy industry over the next few decades to ensure a smooth transition-challenges which will require government and industry solutions beginning as early as today. This paper identifies four critical challenges in energy and the choices which will have to be made on how best to confront growing pollution caused by fossil fuels and how to facilitate an eventual revolutionary-like transition to a non-carbon-based global economy

  11. The challenge of sustainability

    International Nuclear Information System (INIS)

    Orr, D.W.

    1993-01-01

    This paper discusses sustainability in a world that has changed rapidly. The author suggests that ecological assumptions embedded in communism and capitalism are badly flawed, but the flaws were not apparent when there were fewer than a billion people on earth living at low technology levels. Sustaining the earth's vital signs is a challenge to our perception of time, and the numbers - population, environmental damage, oil consumption, waste disposal - are too large to comprehend easily. There is a global debate about what sustainability means. In fact the challenge of sustainability is 6 different challenges: overcoming the tendency to deny inconvenient realities; establishing accurate indicators of human and ecological health; questions about the kinds of technology necessary to make the transition to sustainability; education; the need for an emotional bond between man and nature; rebuilding the existing democratic institutions. 16 refs

  12. Centennial Challenges Program

    Science.gov (United States)

    Ortega, Sam; Eberly, Eric

    2015-01-01

    NASA's Centennial Challenges Program was initiated in 2005 to directly engage the public in the process of advanced technology development. The program offers incentive prizes to generate revolutionary solutions to problems of interest to NASA and the nation. The program seeks innovations from diverse and nontraditional sources. Competitors are not supported by government funding and awards are only made to successful teams when the challenges are met. In keeping with the spirit of the Wright Brothers and other American innovators, the Centennial Challenge prizes are offered to independent inventors including small businesses, student groups, and individuals. These independent inventors are sought to generate innovative solutions for technical problems of interest to NASA and the nation and to provide them with the opportunity to stimulate or create new business ventures.

  13. Primate Auditory Recognition Memory Performance Varies With Sound Type

    OpenAIRE

    Chi-Wing, Ng; Bethany, Plakke; Amy, Poremba

    2009-01-01

    Neural correlates of auditory processing, including for species-specific vocalizations that convey biological and ethological significance (e.g. social status, kinship, environment),have been identified in a wide variety of areas including the temporal and frontal cortices. However, few studies elucidate how non-human primates interact with these vocalization signals when they are challenged by tasks requiring auditory discrimination, recognition, and/or memory. The present study employs a de...

  14. Small finance banks: Challenges

    Directory of Open Access Journals (Sweden)

    Jayadev M

    2017-12-01

    Full Text Available A recent innovation in the Indian banking structure has been the formation of a new banking institution—small finance banks (SFBs. These banks are expected to penetrate into financial inclusion by providing basic banking and credit services with a differentiated banking model to the larger population. In this context the new SFBs have multiple challenges in coming out with a new, differentiated business model. The challenges include building low cost liability portfolio, technology management, and balancing the regulatory compliances. This paper also presents the top of mind views of three senior executives of new small finance banks.

  15. Challenges facing production grids

    Energy Technology Data Exchange (ETDEWEB)

    Pordes, Ruth; /Fermilab

    2007-06-01

    Today's global communities of users expect quality of service from distributed Grid systems equivalent to that their local data centers. This must be coupled to ubiquitous access to the ensemble of processing and storage resources across multiple Grid infrastructures. We are still facing significant challenges in meeting these expectations, especially in the underlying security, a sustainable and successful economic model, and smoothing the boundaries between administrative and technical domains. Using the Open Science Grid as an example, I examine the status and challenges of Grids operating in production today.

  16. The challenge of conceiving

    DEFF Research Database (Denmark)

    Hansen, Claus Thorp; Jørgensen, Ulrik

    2011-01-01

    the perspective of engineering design challenges where the need for problem identification is obvious to avoid the pitfall to reproduce and piecemeal engineer already existing product or service concepts. Problem identification is not a simple desk research task as it often involves a multitude of actors having......One of the big challenges in the CDIO approach to engineering education is the first part focusing on conceiving problems to be handled and eventually solved. Traditional engineering education has been dominated by its focus on technical disciplines emphasising their individual tool box of problem...

  17. Experimental investigation of hole boring and light sail regimes of RPA by varying laser and target parameters

    Czech Academy of Sciences Publication Activity Database

    Kar, S.; Kakolee, K.F.; Cerchez, M.; Doria, D.; Macchi, A.; McKenna, P.; Neely, D.; Osterholz, J.; Quinn, K.; Ramakrishna, B.; Sarri, G.; Willi, O.; Yuan, X.H.; Zepf, M.; Borghesi, Marco

    2013-01-01

    Roč. 55, č. 12 (2013), "124030-1"-"124030-6" ISSN 0741-3335 R&D Projects: GA MŠk ED1.1.00/02.0061; GA MŠk EE2.3.20.0279 Grant - others:ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; LaserZdroj (OP VK 3)(XE) CZ.1.07/2.3.00/20.0279 Institutional support: RVO:68378271 Keywords : plasmas * absorption Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.386, year: 2013

  18. Stressful colours : corticosterone concentrations in a free-living songbird vary with the spectral composition of experimental illumination

    NARCIS (Netherlands)

    Ouyang, Jenny Q.; de Jong, Maaike; Hau, Michaela; Visser, Marcel E.; van Grunsven, Roy H. A.; Spoelstra, Kamiel

    2015-01-01

    Organisms have evolved under natural daily light/dark cycles for millions of years. These cycles have been disturbed as night-time darkness is increasingly replaced by artificial illumination. Investigating the physiological consequences of free-living organisms in artificially lit environments is

  19. Experimental approach to controllably vary protein oxidation while minimizing electrode adsorption for boron-doped diamond electrochemical surface mapping applications.

    Science.gov (United States)

    McClintock, Carlee S; Hettich, Robert L

    2013-01-02

    Oxidative protein surface mapping has become a powerful approach for measuring the solvent accessibility of folded protein structures. A variety of techniques exist for generating the key reagent (i.e., hydroxyl radicals) for these measurements; however, these approaches range significantly in their complexity and expense of operation. This research expands upon earlier work to enhance the controllability of boron-doped diamond (BDD) electrochemistry as an easily accessible tool for producing hydroxyl radicals in order to oxidize a range of intact proteins. Efforts to modulate the oxidation level while minimizing the adsorption of protein to the electrode involved the use of relatively high flow rates to reduce protein residence time inside the electrochemical flow chamber. Additionally, a different cell activation approach using variable voltage to supply a controlled current allowed us to precisely tune the extent of oxidation in a protein-dependent manner. In order to gain perspective on the level of protein adsorption onto the electrode surface, studies were conducted to monitor protein concentration during electrolysis and gauge changes in the electrode surface between cell activation events. This report demonstrates the successful use of BDD electrochemistry for greater precision in generating a target number of oxidation events upon intact proteins.

  20. Experimental investigation of hole boring and light sail regimes of RPA by varying laser and target parameters

    International Nuclear Information System (INIS)

    Kar, S; Kakolee, K F; Doria, D; Quinn, K; Ramakrishna, B; Sarri, G; Zepf, M; Borghesi, M; Cerchez, M; Osterholz, J; Willi, O; Macchi, A; McKenna, P; Yuan, X H; Neely, D

    2013-01-01

    Temporal evolution of plasma jets from micrometre-scale thick foils following the interaction of intense (3 × 10 20  W cm −2 ) laser pulses is studied systematically by time resolved optical interferometry. The fluid velocity in the plasma jets is determined by comparing the data with 2D hydrodynamic simulation, which agrees with the expected hole-boring (HB) velocity due to the laser radiation pressure. The homogeneity of the plasma density across the jets has been found to be improved substantially when irradiating the laser at circular polarization compared to linear polarization. While overdense plasma jets were formed efficiently for micrometre thick targets, decreasing the target areal density and/or increasing the irradiance on the target have provided indication of transition from the ‘HB’ to the ‘light sail (LS)’ regime of RPA, characterized by the appearance of narrow-band spectral features at several MeV/nucleon in proton and carbon spectra. (paper)

  1. Determination of time- and size-dependent fine particle emission with varied oil heating in an experimental kitchen.

    Science.gov (United States)

    Li, Shuangde; Gao, Jiajia; He, Yiqing; Cao, Liuxu; Li, Ang; Mo, Shengpeng; Chen, Yunfa; Cao, Yaqun

    2017-01-01

    Particulate matter (PM) from cooking has caused seriously indoor air pollutant and aroused risk to human health. It is urged to get deep knowledge of their spatial-temporal distribution of source emission characteristics, especially ultrafine particles (UFP<100nm) and accumulation mode particles (AMP 100-665nm). Four commercial cooking oils are auto dipped water to simulate cooking fume under heating to 265°C to investigate PM emission and decay features between 0.03 and 10μm size dimension by electrical low pressure impactor (ELPI) without ventilation. Rapeseed and sunflower produced high PM 2.5 around 6.1mg/m 3 , in comparison with those of soybean and corn (5.87 and 4.65mg/m 3 , respectively) at peak emission time between 340 and 460sec since heating oil, but with the same level of particle numbers 6-9×10 5 /cm 3 . Mean values of PM 1.0 /PM 2.5 and PM 2.5 /PM 10 at peak emission time are around 0.51-0.66 and 0.23-0.29. After 15min naturally deposition, decay rates of PM 1.0 , PM 2.5 and PM 10 are 13.3%-29.8%, 20.1%-33.9% and 41.2%-54.7%, which manifest that PM 1.0 is quite hard to decay than larger particles, PM 2.5 and PM 10 . The majority of the particle emission locates at 43nm with the largest decay rate at 75%, and shifts to a larger size between 137 and 655nm after 15min decay. The decay rates of the particles are sensitive to the oil type. Copyright © 2016. Published by Elsevier B.V.

  2. Stressful colours: corticosterone concentrations in a free-living songbird vary with the spectral composition of experimental illumination

    NARCIS (Netherlands)

    Ouyang, J.; Jong, de M.J.; Hau, M.; Visser, M.E.; Grunsven, van R.H.A.; Spoelstra, K.

    2015-01-01

    Organisms have evolved under natural daily light/dark cycles for millions of years. These cycles have been disturbed as night-time darkness is increasingly replaced by artificial illumination. Investigating the physiological consequences of free-living organisms in artificially lit environments is

  3. Experimental Engineering: Articulating and Valuing Design Experimentation

    DEFF Research Database (Denmark)

    Vallgårda, Anna; Grönvall, Erik; Fritsch, Jonas

    2017-01-01

    In this paper we propose Experimental Engineering as a way to articulate open- ended technological experiments as a legitimate design research practice. Experimental Engineering introduces a move away from an outcome or result driven design process towards an interest in existing technologies and...

  4. Global Stability of Polytopic Linear Time-Varying Dynamic Systems under Time-Varying Point Delays and Impulsive Controls

    Directory of Open Access Journals (Sweden)

    M. de la Sen

    2010-01-01

    Full Text Available This paper investigates the stability properties of a class of dynamic linear systems possessing several linear time-invariant parameterizations (or configurations which conform a linear time-varying polytopic dynamic system with a finite number of time-varying time-differentiable point delays. The parameterizations may be timevarying and with bounded discontinuities and they can be subject to mixed regular plus impulsive controls within a sequence of time instants of zero measure. The polytopic parameterization for the dynamics associated with each delay is specific, so that (q+1 polytopic parameterizations are considered for a system with q delays being also subject to delay-free dynamics. The considered general dynamic system includes, as particular cases, a wide class of switched linear systems whose individual parameterizations are timeinvariant which are governed by a switching rule. However, the dynamic system under consideration is viewed as much more general since it is time-varying with timevarying delays and the bounded discontinuous changes of active parameterizations are generated by impulsive controls in the dynamics and, at the same time, there is not a prescribed set of candidate potential parameterizations.

  5. Optimality-theoretic pragmatics meets experimental pragmatics

    NARCIS (Netherlands)

    Blutner, R.; Benz, A.; Blutner, R.

    2009-01-01

    The main concern of this article is to discuss some recent findings concerning the psychological reality of optimality-theoretic pragmatics and its central part - bidirectional optimization. A present challenge is to close the gap between experimental pragmatics and neo-Gricean theories of

  6. Lichen Persistence and Recovery in Response to Varied Volcanic Disturbances

    Science.gov (United States)

    Nelson, P.; Wheeler, T. B.

    2015-12-01

    Volcanic eruptions produce many ecological disturbances that structure vegetation. While lichens are sensitive to disturbances, little is known about their responses to volcanic disturbances, except for colonization of lava. We examined lichen community responses through time to different disturbances produced by the May 1, 2008 eruption of Volcan Chaiten in south-central Chile. Pre-eruption vegetation near the volcano was old-growth Valdivian temperate rainforest dominated by closed-canopy Nothofagus sp... In 2012, we installed thirteen 1-acre plots across volcanic disturbance zones on which a time-constrained search was done for all macrolichen species, each of which was assigned an approximate log10 categorical abundance. We also installed a 0.2 m2 quadrat on two representative trees per plot for repeat photography of lichen cover. We remeasured at least one plot per disturbance zone in 2014 and re-photographed tree quadrats in 2013 and 2014. We then analyzed species composition and abundance differences among disturbance zones. In 2012, the blast (pyroclastic density flow), scorch (standing scorched forest at the edge of the blast) and deep tephra (>10 cm) zones had the lowest lichen species richness (5-13 species), followed by reference (unimpacted) and shallow (lichen species since 2012 while the light tephra and reference were essentially unchanged. Gravel rain, gravel rain + pumice and flooded forest plots all had about the same number of species in 2014 as 2012. Lichen colonization and growth in tree quadrats varied widely, from very little colonization in the blast to prolific colonization in the gravel rain + pumice zone. Lichen's varied responses to different volcanic disturbances were attributable to varying degrees of mortality and subsequent availability of substrate, quantity of light and removal of competitors. While sensitive to disturbance, lichens are apparently resilient to and can quickly recolonize after a variety of large, violent volcanic

  7. Forming of Zr-4 alloy guide tube with varied diameters

    International Nuclear Information System (INIS)

    Wei Songyan; Tian Zhenye

    1989-10-01

    A new built-up mould method to manufacture Zr-4 alloy guide tubes with varied diameters at the middle of tube is introduced. The guide tube is used in nuclear power plants for guiding the control rods. This method has many advantages such as simple in forming, low cost of manufacturing, no need of special devices and favour of batch processing. The test results show that the accuracy of size, mechanical properties, resistance to corrosion, grain size and hydrogenate orientation of the end-products can meet the technical needs for nuclear reactor operation

  8. Varied clinico-radiological presentations of transmigrated canines

    Directory of Open Access Journals (Sweden)

    Ishita Gupta

    2015-01-01

    Full Text Available Canine is one of the most commonly impacted teeth in the dental arch. An unerupted permanent canine crossing the midline is called transmigration and is an unusual event. We report nine cases of impacted canine transmigration. Maxillary canine transmigration, bilateral transmigration, and transmigration associated with odontoma are rare presentations. This article discusses the varied clinico-radiologic presentations, etiology, and treatment options of transmigration. It also emphasizes the importance of panoramic radiographs for evaluation of over-retained deciduous canines or missing permanent canines.

  9. Plasma acceleration in a wave with varying frequency

    International Nuclear Information System (INIS)

    Petrzilka, V.A.

    1978-01-01

    The averaged velocity of a test particle and the averaged velocity of a plasma in an electromagnetic wave packet with varying frequency (e.g., a radiation pulse from pulsar) is derived. The total momentum left by the wave packet in regions of plasma inhomogeneity is found. In case the plasma concentration is changing due to ionization the plasma may be accelerated parallelly or antiparallelly to the direction of the wave packet propagation which is relevant for a laser induced breakdown in gas. (author)

  10. Structured Linear Parameter Varying Control of Wind Turbines

    DEFF Research Database (Denmark)

    Adegas, Fabiano Daher; Sloth, Christoffer; Stoustrup, Jakob

    2012-01-01

    High performance and reliability are required for wind turbines to be competitive within the energy market. To capture their nonlinear behavior, wind turbines are often modeled using parameter-varying models. In this chapter, a framework for modelling and controller design of wind turbines is pre...... in the controller synthesis are solved by an iterative LMI-based algorithm. The resulting controllers can also be easily implemented in practice due to low data storage and simple math operations. The performance of the LPV controllers is assessed by nonlinear simulations results....

  11. Toluene metabolism during exposure to varying concentrations combined with exercise

    DEFF Research Database (Denmark)

    Bælum, Jesper; Døssing, M; Hansen, S H

    1987-01-01

    . In Study A, four males were exposed to clean air and to constant and varying concentrations of toluene in combination with rest and with 100 W exercise in 140 min. Exercise increased end exposure excretion rate of HA and O-cr by 47 and 114%, respectively. After exposure, all excess HA was excreted within 4...... weight and smoking habits, thus influencing the metabolite concentration standardised in relation to creatinine. It is concluded that both metabolites are estimates of toluene exposure. O-cr is more specific than HA, but the individual variation in excretion of both metabolites is large, and when...

  12. Reduced dielectric response in spatially varying electric fields

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt

    2015-01-01

    relations between the flux and the gradient of the polarization. Comparison between the theory and molecular dynamics simulations confirms this effect. The effect is significant for small length scale electric field variations and the inclusion of the flux is thus important in nanoscale modeling......In this paper, the dynamical equation for polarization is derived. From this the dielectric response to a spatially varying electric field is analyzed showing a reduced response due to flux of polarization in the material. This flux is modeled as a diffusive process through linear constitutive...

  13. Time Varying Market Integration and Expected Rteurns in Emerging Markets

    OpenAIRE

    Jong, F.C.J.M. de; Roon, F.A. de

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematic risk as measured by their beta relative to the world portfolio as well as on the level of integration in that market.The level of integration is a time-varying variable that depends on the market value of the assets that can be held by domestic investors only versus the market value of the assets that can be traded freely.Our empirical analysis for 30 emerging markets shows that there are strong...

  14. Robust topology optimization accounting for spatially varying manufacturing errors

    DEFF Research Database (Denmark)

    Schevenels, M.; Lazarov, Boyan Stefanov; Sigmund, Ole

    2011-01-01

    This paper presents a robust approach for the design of macro-, micro-, or nano-structures by means of topology optimization, accounting for spatially varying manufacturing errors. The focus is on structures produced by milling or etching; in this case over- or under-etching may cause parts...... optimization problem is formulated in a probabilistic way: the objective function is defined as a weighted sum of the mean value and the standard deviation of the structural performance. The optimization problem is solved by means of a Monte Carlo method: in each iteration of the optimization scheme, a Monte...

  15. Measurement of periodically varying ECE spectra using a Michelson interferometer

    International Nuclear Information System (INIS)

    Laurent, L.; Rodriguez, L.; Talvard, M.

    1987-01-01

    In some tokamak experiments the ECE spectrum is periodically varying. If the modulation frequency is small enough (less than 10 Hz) the plasma can be considered as quasi-stationary during the typical scan time of most of the Michelson interferometers. It is possible to measure simply ECE spectra at different times of the oscillation. We present here a technique which allows to measure smaller fluctuations at larger frequencies. However the analysis requires a large number of periods of oscillation at constant frequency and a scanning mirror moving at constant velocity

  16. Modelling Acoustic Wave Propagation in Axisymmetric Varying-Radius Waveguides

    DEFF Research Database (Denmark)

    Bæk, David; Willatzen, Morten

    2008-01-01

    A computationally fast and accurate model (a set of coupled ordinary differential equations) for fluid sound-wave propagation in infinite axisymmetric waveguides of varying radius is proposed. The model accounts for fluid heat conduction and fluid irrotational viscosity. The model problem is solved...... by expanding solutions in terms of cross-sectional eigenfunctions following Stevenson’s method. A transfer matrix can be easily constructed from simple model responses of a given waveguide and later used in computing the response to any complex wave input. Energy losses due to heat conduction and viscous...

  17. One-dimensional radionuclide transport under time-varying conditions

    International Nuclear Information System (INIS)

    Gelbard, F.; Olague, N.E.; Longsine, D.E.

    1990-01-01

    This paper discusses new analytical and numerical solutions presented for one-dimensional radionuclide transport under time-varying fluid-flow conditions including radioactive decay. The analytical solution assumes that all radionuclides have identical retardation factors, and is limited to instantaneous releases. The numerical solution does not have these limitations, but is tested against the limiting case given for the analytical solution. Reasonable agreement between the two solutions was found. Examples are given for the transport of a three-member radionuclide chain transported over distances and flow rates comparable to those reported for Yucca Mountain, the proposed disposal site for high-level nuclear waste

  18. Timed arrays wideband and time varying antenna arrays

    CERN Document Server

    Haupt, Randy L

    2015-01-01

    Introduces timed arrays and design approaches to meet the new high performance standards The author concentrates on any aspect of an antenna array that must be viewed from a time perspective. The first chapters briefly introduce antenna arrays and explain the difference between phased and timed arrays. Since timed arrays are designed for realistic time-varying signals and scenarios, the book also reviews wideband signals, baseband and passband RF signals, polarization and signal bandwidth. Other topics covered include time domain, mutual coupling, wideband elements, and dispersion. The auth

  19. Epidemic spreading in time-varying community networks.

    Science.gov (United States)

    Ren, Guangming; Wang, Xingyuan

    2014-06-01

    The spreading processes of many infectious diseases have comparable time scale as the network evolution. Here, we present a simple networks model with time-varying community structure, and investigate susceptible-infected-susceptible epidemic spreading processes in this model. By both theoretic analysis and numerical simulations, we show that the efficiency of epidemic spreading in this model depends intensively on the mobility rate q of the individuals among communities. We also find that there exists a mobility rate threshold qc. The epidemic will survive when q > qc and die when q epidemic spreading in complex networks with community structure.

  20. Projectile Motion Hoop Challenge

    Science.gov (United States)

    Jordan, Connor; Dunn, Amy; Armstrong, Zachary; Adams, Wendy K.

    2018-01-01

    Projectile motion is a common phenomenon that is used in introductory physics courses to help students understand motion in two dimensions. Authors have shared a range of ideas for teaching this concept and the associated kinematics in "The Physics Teacher" ("TPT"); however, the "Hoop Challenge" is a new setup not…

  1. A Challenge to Watson

    Science.gov (United States)

    Detterman, Douglas K.

    2011-01-01

    Watson's Jeopardy victory raises the question of the similarity of artificial intelligence and human intelligence. Those of us who study human intelligence issue a challenge to the artificial intelligence community. We will construct a unique battery of tests for any computer that would provide an actual IQ score for the computer. This is the same…

  2. Challenging and valuable

    NARCIS (Netherlands)

    Van Hal, J.D.M.

    2008-01-01

    Challenging and valuable Inaugural speech given on May 7th 2008 at the occasion of the acceptance of the position of Professor Sustainable Housing Transformation at the faculty of Architeeture of the Delft University of Technology by Prof. J.D.M. van Hal MSc PhD.

  3. The energy challenge

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter addresses the challenge of switching US energy dependency from fossil fuels to renewable sources of energy for economic and environmental reasons. The topics discussed include the role of fossil fuels in the US economy, the role of chlorofluorocarbons and fossil fuel combustion on the greenhouse effect, energy choices, and the role of energy efficiency and nuclear energy

  4. The diesel challenge

    International Nuclear Information System (INIS)

    Tobin, Geoff

    1997-01-01

    This article is focused on the challenges being faced by the diesel producer and these include a number of interesting developments which illustrate the highly competitive world of the European refiner. These include: The tightening quality requirements being legislated coupled with the availability of the ''city diesel'' from Scandinavia and elsewhere which is already being sold into the market. For a time there will be a clear means of product differentiation. One of the key questions is whether the consumer will value the quality difference; a growing demand for diesel which is outstripping the growth in gasoline demand and causing refiners headaches when it comes to balancing their supply/demand barrels; the emergence of alternative fuels which are challenging the traditional markets of the refiner and in particular, the niche markets for the higher quality diesel fuels. All of this at a time of poor margins and over-capacity in the industry with further major challenges ahead such as fuel oil disposal, tighter environmental standards and the likelihood of heavier, higher sulphur crude oils in the future. Clearly, in such a difficult and highly-competitive business environment it will be important to find low-cost solutions to the challenges of the diesel quality changes. An innovative approach will be required to identify the cheapest and best route to enable the manufacture of the new quality diesel. (Author)

  5. The Moon Challenge

    Science.gov (United States)

    Fitzsimmons, Pat; Leddy, Diana; Johnson, Lindy; Biggam, Sue; Locke, Suzan

    2013-01-01

    This article describes a first-grade research project that incorporates trade books and challenges misconceptions. Educators see the power of their students' wonder at work in their classrooms on a daily basis. This wonder must be nourished by students' own experiences--observing the moon on a crystal clear night--as well as by having…

  6. Rooftop Garden Design Challenge

    Science.gov (United States)

    Roman, Harry T.

    2010-01-01

    A small commercial building in a nearby industrial park has decided to install a rooftop garden for its employees to enjoy. The garden will be about 100 feet long and 75 feet wide. This article presents a design challenge for technology and engineering students wherein they will assist in the initial conceptual design of the rooftop garden. The…

  7. Hopes and Challenges

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    China tops the medal tally again at the Asian Games but still faces challenges in some events The curtain of the 16th Asian Games has fallen, but the 15 days of exciting competitions will be recorded in the history of the Games.

  8. Communication Challenge Softball

    Science.gov (United States)

    Moran, Tom; Vance, Mike

    2005-01-01

    Communication Challenge Softball is a developmentally appropriate game for middle school students. The game allows them to develop new communication skills using American Sign Language (signing). Traditional softball has been a part of physical education for years, and remains a popular sport played by children in community leagues throughout the…

  9. Electric Vehicle Battery Challenge

    Science.gov (United States)

    Roman, Harry T.

    2014-01-01

    A serious drawback to electric vehicles [batteries only] is the idle time needed to recharge their batteries. In this challenge, students can develop ideas and concepts for battery change-out at automotive service stations. Such a capability would extend the range of electric vehicles.

  10. Common Breastfeeding Challenges

    Science.gov (United States)

    ... or duplicated without permission of the Office on Women’s Health in the U.S. Department of Health and Human Services. Citation of the source is appreciated. Page last updated: March 02, 2018. Common breastfeeding challenges Breastfeeding can be ...

  11. BPI Challenge 2014

    NARCIS (Netherlands)

    Dongen, B.F. van

    2014-01-01

    BPI Challenge 2014: Similar to other ICT companies, Rabobank Group ICT has to implement an increasing number of software releases, while the time to market is decreasing. Rabobank Group ICT has implemented the ITIL-processes and therefore uses the Change-proces for implementing these so called

  12. The Challenges in Communication

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. The Challenges in Communication. The conflict between connection oriented and connectionless. The seamless integration needs of broadcast, unicast and multicast in the midst growing security concerns. Like Indian roads – need to carry voice, internet traffic, video ...

  13. Biggest challenges in bioinformatics.

    Science.gov (United States)

    Fuller, Jonathan C; Khoueiry, Pierre; Dinkel, Holger; Forslund, Kristoffer; Stamatakis, Alexandros; Barry, Joseph; Budd, Aidan; Soldatos, Theodoros G; Linssen, Katja; Rajput, Abdul Mateen

    2013-04-01

    The third Heidelberg Unseminars in Bioinformatics (HUB) was held on 18th October 2012, at Heidelberg University, Germany. HUB brought together around 40 bioinformaticians from academia and industry to discuss the 'Biggest Challenges in Bioinformatics' in a 'World Café' style event.

  14. Biggest challenges in bioinformatics

    OpenAIRE

    Fuller, Jonathan C; Khoueiry, Pierre; Dinkel, Holger; Forslund, Kristoffer; Stamatakis, Alexandros; Barry, Joseph; Budd, Aidan; Soldatos, Theodoros G; Linssen, Katja; Rajput, Abdul Mateen

    2013-01-01

    The third Heidelberg Unseminars in Bioinformatics (HUB) was held in October at Heidelberg University in Germany. HUB brought together around 40 bioinformaticians from academia and industry to discuss the ‘Biggest Challenges in Bioinformatics' in a ‘World Café' style event.

  15. Future nuclear regulatory challenges

    International Nuclear Information System (INIS)

    Royen, J.

    1998-01-01

    In December 1996, the NEA Committee on Nuclear Regulatory Activities concluded that changes resulting from economic deregulation and other recent developments affecting nuclear power programmes have consequences both for licensees and regulatory authorities. A number of potential problems and issues which will present a challenge to nuclear regulatory bodies over the next ten years have been identified in a report just released. (author)

  16. Challenge Beginning Teacher Beliefs

    Science.gov (United States)

    Lannin, John K.; Chval, Kathryn B.

    2013-01-01

    As beginning teachers start to recognize the complexity of teaching mathematics in elementary school classrooms and how their new vision for teaching mathematics creates new challenges, they experience discomfort--a healthy awareness that much is to be learned. Brousseau (1997) notes that changes in the roles that are implicitly assigned to the…

  17. Asia's new challenges

    DEFF Research Database (Denmark)

    Brach, Juliana; Vang, Jan

    2012-01-01

    Asian countries are currently undergoing significant changes with respect to their role in and interaction with the international economy. Despite their heterogeneity, Asian countries share the common aim to upgrade capacities, skills and capabilities. This paper aims at unpacking the challenges ...

  18. Rapid Engineering of Foot-and-Mouth Disease Vaccine and Challenge Viruses.

    Science.gov (United States)

    Lee, Seo-Yong; Lee, Yeo-Joo; Kim, Rae-Hyung; Park, Jeong-Nam; Park, Min-Eun; Ko, Mi-Kyeong; Choi, Joo-Hyung; Chu, Jia-Qi; Lee, Kwang-Nyeong; Kim, Su-Mi; Tark, Dongseob; Lee, Hyang-Sim; Ko, Young-Joon; Seo, Min-Goo; Park, Jung-Won; Kim, Byounghan; Lee, Myoung-Heon; Lee, Jong-Soo; Park, Jong-Hyeon

    2017-08-15

    There are seven antigenically distinct serotypes of foot-and-mouth disease virus (FMDV), each of which has intratypic variants. In the present study, we have developed methods to efficiently generate promising vaccines against seven serotypes or subtypes. The capsid-encoding gene (P1) of the vaccine strain O1/Manisa/Turkey/69 was replaced with the amplified or synthetic genes from the O, A, Asia1, C, SAT1, SAT2, and SAT3 serotypes. Viruses of the seven serotype were rescued successfully. Each chimeric FMDV with a replacement of P1 showed serotype-specific antigenicity and varied in terms of pathogenesis in pigs and mice. Vaccination of pigs with an experimental trivalent vaccine containing the inactivated recombinants based on the main serotypes O, A, and Asia1 effectively protected them from virus challenge. This technology could be a potential strategy for a customized vaccine with challenge tools to protect against epizootic disease caused by specific serotypes or subtypes of FMDV. IMPORTANCE Foot-and-mouth disease (FMD) virus (FMDV) causes significant economic losses. For vaccine preparation, the selection of vaccine strains was complicated by high antigenic variation. In the present study, we suggested an effective strategy to rapidly prepare and evaluate mass-produced customized vaccines against epidemic strains. The P1 gene encoding the structural proteins of the well-known vaccine virus was replaced by the synthetic or amplified genes of viruses of seven representative serotypes. These chimeric viruses generally replicated readily in cell culture and had a particle size similar to that of the original vaccine strain. Their antigenicity mirrored that of the original serotype from which their P1 gene was derived. Animal infection experiments revealed that the recombinants varied in terms of pathogenicity. This strategy will be a useful tool for rapidly generating customized FMD vaccines or challenge viruses for all serotypes, especially for FMD-free countries

  19. Seven challenges for neuroscience.

    Science.gov (United States)

    Markram, Henry

    2013-01-01

    Although twenty-first century neuroscience is a major scientific enterprise, advances in basic research have not yet translated into benefits for society. In this paper, I outline seven fundamental challenges that need to be overcome. First, neuroscience has to become "big science" - we need big teams with the resources and competences to tackle the big problems. Second, we need to create interlinked sets of data providing a complete picture of single areas of the brain at their different levels of organization with "rungs" linking the descriptions for humans and other species. Such "data ladders" will help us to meet the third challenge - the development of efficient predictive tools, enabling us to drastically increase the information we can extract from expensive experiments. The fourth challenge goes one step further: we have to develop novel hardware and software sufficiently powerful to simulate the brain. In the future, supercomputer-based brain simulation will enable us to make in silico manipulations and recordings, which are currently completely impossible in the lab. The fifth and sixth challenges are translational. On the one hand we need to develop new ways of classifying and simulating brain disease, leading to better diagnosis and more effective drug discovery. On the other, we have to exploit our knowledge to build new brain-inspired technologies, with potentially huge benefits for industry and for society. This leads to the seventh challenge. Neuroscience can indeed deliver huge benefits but we have to be aware of widespread social concern about our work. We need to recognize the fears that exist, lay them to rest, and actively build public support for neuroscience research. We have to set goals for ourselves that the public can recognize and share. And then we have to deliver on our promises. Only in this way, will we receive the support and funding we need.

  20. Renewable energies: public policy challenges

    International Nuclear Information System (INIS)

    Grazi, Laure; Souletie, Arthur

    2016-03-01

    Renewable energy sources (RES) are low-carbon energies available right within our borders, and as such can be of great value in addressing the challenges of climate change and energy security. In 2014, renewable energies accounted for 14.6% of France's gross final energy consumption. The French Energy Transition Act for Green Growth sets renewables targets of 23% and 32% as a share of gross final energy consumption by 2020 and 2030, respectively. However, renewable energies are still more costly than conventional energies. A significant share of this additional cost is borne by energy consumers, particularly in the form of energy taxation and biofuels blending obligations. Public aid is also provided to support heat production from renewable energy sources (RES-H). The two most significant aids available today are the Energy Transition Tax Credit (CITE) and the Heat Fund. Comparing the various types of renewable energies shows sharp disparities in terms of the cost of avoiding one tonne of CO 2 , which ranges from euros 59 to more than euros 500 for electricity production it follows that the cost of the energy transition is likely to vary significantly depending on which renewable energy sources are pushed to the fore. The combustion of biomass for heat production appears to offer an economically efficient way to reduce CO 2 emissions. Of the various renewable technologies available for the production of electricity (with the exception of hydropower, which was excluded from the scope of this study), onshore wind power is the least costly

  1. Quantitative characterization of steady and time-varying, sooting, laminar diffusion flames using optical techniques

    Science.gov (United States)

    Connelly, Blair C.

    In order to reduce the emission of pollutants such as soot and NO x from combustion systems, a detailed understanding of pollutant formation is required. In addition to environmental concerns, this is important for a fundamental understanding of flame behavior as significant quantities of soot lower local flame temperatures, increase overall flame length and affect the formation of such temperature-dependent species as NOx. This problem is investigated by carrying out coupled computational and experimental studies of steady and time-varying sooting, coflow diffusion flames. Optical diagnostic techniques are a powerful tool for characterizing combustion systems, as they provide a noninvasive method of probing the environment. Laser diagnostic techniques have added advantages, as systems can be probed with high spectral, temporal and spatial resolution, and with species selectivity. Experimental soot volume fractions were determined by using two-dimensional laser-induced incandescence (LII), calibrated with an on-line extinction measurement, and soot pyrometry. Measurements of soot particle size distributions are made using time-resolved LII (TR-LII). Laser-induced fluorescence measurements are made of NO and formaldehyde. These experimental measurements, and others, are compared with computational results in an effort to understand and model soot formation and to examine the coupled relationship of soot and NO x formation.

  2. 76 FR 41526 - Centennial Challenges 2011 Strong Tether Challenge

    Science.gov (United States)

    2011-07-14

    ... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice (11-063)] Centennial Challenges 2011 Strong... scheduled and teams that wish to compete may register. Centennial Challenges is a program of prize... NASA Centennial Challenges Program please visit: http://www.nasa.gov/challenges . General questions and...

  3. 78 FR 19742 - Centennial Challenges: 2014 Night Rover Challenge

    Science.gov (United States)

    2013-04-02

    ... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice 13-032] Centennial Challenges: 2014 Night... Centennial Challenges 2014 Night Rover Challenge. SUMMARY: This notice is issued in accordance with 51 U.S.C.... Centennial Challenges is a program of prize competitions to stimulate innovation in technologies of interest...

  4. 78 FR 49296 - Centennial Challenges 2014 Sample Return Robot Challenge

    Science.gov (United States)

    2013-08-13

    ... NATIONAL AERONAUTICS AND SPACE ADMINISTRATION [Notice 13-093] Centennial Challenges 2014 Sample... Centennial Challenges 2014 Sample Return Robot Challenge. SUMMARY: This notice is issued in accordance with... compete may register. Centennial Challenges is a program of prize competitions to stimulate innovation in...

  5. Film Boiling on Downward Quenching Hemisphere of Varying Sizes

    Energy Technology Data Exchange (ETDEWEB)

    Chan S. Kim; Kune Y. Suh; Joy L. Rempe; Fan-Bill Cheung; Sang B. Kim

    2004-04-01

    Film boiling heat transfer coefficients for a downward-facing hemispherical surface are measured from the quenching tests in DELTA (Downward-boiling Experimental Laminar Transition Apparatus). Two test sections are made of copper to maintain low Biot numbers. The outer diameters of the hemispheres are 120 mm and 294 mm, respectively. The thickness of all the test sections is 30 mm. The effect of diameter on film boiling heat transfer is quantified utilizing results obtained from the test sections. The measured data are compared with the numerical predictions from laminar film boiling analysis. The measured heat transfer coefficients are found to be greater than those predicted by the conventional laminar flow theory on account of the interfacial wavy motion incurred by the Helmholtz instability. Incorporation of the wavy motion model considerably improves the agreement between the experimental and numerical results in terms of heat transfer coefficient. In addition, the interfacial wavy motion and the quenching process are visualized through a digital camera.

  6. The extinction probability in systems randomly varying in time

    Directory of Open Access Journals (Sweden)

    Imre Pázsit

    2017-09-01

    Full Text Available The extinction probability of a branching process (a neutron chain in a multiplying medium is calculated for a system randomly varying in time. The evolution of the first two moments of such a process was calculated previously by the authors in a system randomly shifting between two states of different multiplication properties. The same model is used here for the investigation of the extinction probability. It is seen that the determination of the extinction probability is significantly more complicated than that of the moments, and it can only be achieved by pure numerical methods. The numerical results indicate that for systems fluctuating between two subcritical or two supercritical states, the extinction probability behaves as expected, but for systems fluctuating between a supercritical and a subcritical state, there is a crucial and unexpected deviation from the predicted behaviour. The results bear some significance not only for neutron chains in a multiplying medium, but also for the evolution of biological populations in a time-varying environment.

  7. Vibration condition monitoring of planetary gearbox under varying external load

    Energy Technology Data Exchange (ETDEWEB)

    Bartelmus, W.; Zimroz, R. [Wroclaw University of Technology, Wroclaw (Poland)

    2009-01-15

    The paper shows that for condition monitoring of planetary gearboxes it is important to identify the external varying load condition. In the paper, systematic consideration has been taken of the influence of many factors on the vibration signals generated by a system in which a planetary gearbox is included. These considerations give the basis for vibration signal interpretation, development of the means of condition monitoring, and for the scenario of the degradation of the planetary gearbox. Real measured vibration signals obtained in the industrial environment are processed. The signals are recorded during normal operation of the diagnosed objects, namely planetary gearboxes, which are a part of the driving system used in a bucket wheel excavator, used in lignite mines. It has been found that the most important factor of the proper planetary gearbox condition is connected with perturbation of arm rotation, where an arm rotation gives rise to a specific vibration signal whose properties are depicted by a short-time Fourier transform (STFT) and Wigner-Ville distribution presented as a time-frequency map. The paper gives evidence that there are two dominant low-frequency causes that influence vibration signal modulation, i.e. the varying load, which comes from the nature of the bucket wheel digging process, and the arm/carrier rotation. These two causes determine the condition of the planetary gearboxes considered.

  8. Stochastic analysis of epidemics on adaptive time varying networks

    Science.gov (United States)

    Kotnis, Bhushan; Kuri, Joy

    2013-06-01

    Many studies investigating the effect of human social connectivity structures (networks) and human behavioral adaptations on the spread of infectious diseases have assumed either a static connectivity structure or a network which adapts itself in response to the epidemic (adaptive networks). However, human social connections are inherently dynamic or time varying. Furthermore, the spread of many infectious diseases occur on a time scale comparable to the time scale of the evolving network structure. Here we aim to quantify the effect of human behavioral adaptations on the spread of asymptomatic infectious diseases on time varying networks. We perform a full stochastic analysis using a continuous time Markov chain approach for calculating the outbreak probability, mean epidemic duration, epidemic reemergence probability, etc. Additionally, we use mean-field theory for calculating epidemic thresholds. Theoretical predictions are verified using extensive simulations. Our studies have uncovered the existence of an “adaptive threshold,” i.e., when the ratio of susceptibility (or infectivity) rate to recovery rate is below the threshold value, adaptive behavior can prevent the epidemic. However, if it is above the threshold, no amount of behavioral adaptations can prevent the epidemic. Our analyses suggest that the interaction patterns of the infected population play a major role in sustaining the epidemic. Our results have implications on epidemic containment policies, as awareness campaigns and human behavioral responses can be effective only if the interaction levels of the infected populace are kept in check.

  9. Constitutive Equation with Varying Parameters for Superplastic Flow Behavior

    Science.gov (United States)

    Guan, Zhiping; Ren, Mingwen; Jia, Hongjie; Zhao, Po; Ma, Pinkui

    2014-03-01

    In this study, constitutive equations for superplastic materials with an extra large elongation were investigated through mechanical analysis. From the view of phenomenology, firstly, some traditional empirical constitutive relations were standardized by restricting some strain paths and parameter conditions, and the coefficients in these relations were strictly given new mechanical definitions. Subsequently, a new, general constitutive equation with varying parameters was theoretically deduced based on the general mechanical equation of state. The superplastic tension test data of Zn-5%Al alloy at 340 °C under strain rates, velocities, and loads were employed for building a new constitutive equation and examining its validity. Analysis results indicated that the constitutive equation with varying parameters could characterize superplastic flow behavior in practical superplastic forming with high prediction accuracy and without any restriction of strain path or deformation condition, showing good industrial or scientific interest. On the contrary, those empirical equations have low prediction capabilities due to constant parameters and poor applicability because of the limit of special strain path or parameter conditions based on strict phenomenology.

  10. Marijuana smoking: effects of varying puff volume and breathhold duration.

    Science.gov (United States)

    Azorlosa, J L; Greenwald, M K; Stitzer, M L

    1995-02-01

    Two studies were conducted to quantify biological and behavioral effects resulting from exposure to controlled doses of marijuana smoke. In one study, puff volume (30, 60 and 90 ml) and in a second study, breathhold duration (0, 10 and 20 sec) were systematically varied while holding constant other smoking topography parameters (number of puffs = 10, interpuff interval = 60 sec and inhalation volume = 25% of vital capacity). Each study also varied levels of delta 9-tetrahydro-cannabinol marijuana cigarette content (1.75% and 3.55%). Regular marijuana users served as subjects (n = 7 in each experiment). Subjects smoked 10 puffs in each of six sessions; a seventh, nonsmoking session (all measures recorded at the same times as in active smoking sessions) served as a control. Variations in puff volume produced significant dose-related changes in postsmoking plasma delta 9-tetrahydro-cannabinol levels, carbon monoxide boost and subjective effects (e.g., "high"). In contrast, breathholding for 10 or 20 sec versus 0 sec increased plasma delta 9-tetrahydro-cannabinol levels but not CO boost or subjective effects. Task performance measures were not reliably influenced by marijuana smoke exposure within the dosing ranges examined. These findings confirm the utility of the controlled smoking technology, support the notion that cumulative puff volume systematically influences biological exposure and subjective effects, but cast doubt on the common belief that prolonged breathholding of marijuana smoke enhances classical subjective effects associated with its reinforcing value in humans.

  11. Student throughput variables and properties: Varying cohort sizes

    Directory of Open Access Journals (Sweden)

    Lucas C.A. Stoop

    2017-11-01

    Full Text Available A recent research paper described how student throughput variables and properties combine to explain the behaviour of stationary or simplified throughput systems. Such behaviour can be understood in terms of the locus of a point in the triangular admissible region of the H-S plane, where H represents headcounts and S successful credits, each depending on the system properties at that point. The efficiency of the student throughput process is given by the ratio S/H. Simplified throughput systems are characterised by stationary graduation and dropout patterns of students as well as by annual intakes of student cohorts of equal size. The effect of varying the size of the annual intakes of student cohorts is reported on here. The observations made lead to the establishment of a more generalised student throughput theory which includes the simplified theory as a special case. The generalised theory still retains the notion of a triangular admissible region in the H-S plane but with the size and shape of the triangle depending on the size of the student cohorts. The ratio S/H again emerges as the process efficiency measure for throughput systems in general with unchanged roles assigned to important system properties. This theory provides for a more fundamental understanding of student throughput systems encountered in real life. Significance: A generalised stationary student throughput theory through varying cohort sizes allows for a far better understanding of real student throughput systems.

  12. Tolerable Time-Varying Overflow on Grass-Covered Slopes

    Directory of Open Access Journals (Sweden)

    Steven A. Hughes

    2015-03-01

    Full Text Available Engineers require estimates of tolerable overtopping limits for grass-covered levees, dikes, and embankments that might experience steady overflow. Realistic tolerance estimates can be used for both resilient design and risk assessment. A simple framework is developed for estimating tolerable overtopping on grass-covered slopes caused by slowly-varying (in time overtopping discharge (e.g., events like storm surges or river flood waves. The framework adapts the well-known Hewlett curves of tolerable limiting velocity as a function of overflow duration. It has been hypothesized that the form of the Hewlett curves suggests that the grass erosion process is governed by the flow work on the slope above a critical threshold velocity (referred to as excess work, and the tolerable erosional limit is reached when the cumulative excess work exceeds a given value determined from the time-dependent Hewlett curves. The cumulative excess work is expressed in terms of overflow discharge above a critical discharge that slowly varies in time, similar to a discharge hydrograph. The methodology is easily applied using forecast storm surge hydrographs at specific locations where wave action is minimal. For preliminary planning purposes, when storm surge hydrographs are unavailable, hypothetical equations for the water level and overflow discharge hydrographs are proposed in terms of the values at maximum overflow and the total duration of overflow. An example application is given to illustrate use of the methodology.

  13. Slowly varying dilaton cosmologies and their field theory duals

    International Nuclear Information System (INIS)

    Awad, Adel; Das, Sumit R.; Ghosh, Archisman; Oh, Jae-Hyuk; Trivedi, Sandip P.

    2009-01-01

    We consider a deformation of the AdS 5 xS 5 solution of IIB supergravity obtained by taking the boundary value of the dilaton to be time dependent. The time dependence is taken to be slowly varying on the anti-de Sitter (AdS) scale thereby introducing a small parameter ε. The boundary dilaton has a profile which asymptotes to a constant in the far past and future and attains a minimum value at intermediate times. We construct the supergravity (sugra) solution to first nontrivial order in ε, and find that it is smooth, horizon-free, and asymptotically AdS 5 xS 5 in the far future. When the intermediate values of the dilaton becomes small enough the curvature becomes of order the string scale and the sugra approximation breaks down. The resulting dynamics is analyzed in the dual SU(N) gauge theory on S 3 with a time dependent coupling constant which varies slowly. When Nε 5 xS 5 again. When Nε>>1, we formulate a classical adiabatic perturbation theory based on coherent states which arises in the large N limit. For large values of the 't Hooft coupling this reproduces the supergravity results. For small 't Hooft coupling the coherent state calculations become involved and we cannot reach a definite conclusion. We argue that the final state should have a dual description which is mostly smooth AdS 5 space with the possible presence of a small black hole.

  14. Plant Mating Systems Often Vary Widely Among Populations

    Directory of Open Access Journals (Sweden)

    Michael R. Whitehead

    2018-04-01

    Full Text Available Most flowering plants are hermaphroditic, yet the proportion of seeds fertilized by self and outcross pollen varies widely among species, ranging from predominant self-fertilization to exclusive outcrossing. A population's rate of outcrossing has important evolutionary outcomes as it influences genetic structure, effective population size, and offspring fitness. Because most mating system studies have quantified outcrossing rates for just one or two populations, past reviews of mating system diversity have not been able to characterize the extent of variation among populations. Here we present a new database of more than 30 years of mating system studies that report outcrossing rates for three or more populations per species. This survey, which includes 741 populations from 105 species, illustrates substantial and prevalent among-population variation in the mating system. Intermediate outcrossing rates (mixed mating are common; 63% of species had at least one mixed mating population. The variance among populations and within species was not significantly correlated with pollination mode or phylogeny. Our review underscores the need for studies exploring variation in the relative influence of ecological and genetic factors on the mating system, and how this varies among populations. We conclude that estimates of outcrossing rates from single populations are often highly unreliable indicators of the mating system of an entire species.

  15. Study of selected phenotype switching strategies in time varying environment

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, Denis, E-mail: horvath.denis@gmail.com [Centre of Interdisciplinary Biosciences, Institute of Physics, Faculty of Science, P.J. Šafárik University in Košice, Jesenná 5, 040 01 Košice (Slovakia); Brutovsky, Branislav, E-mail: branislav.brutovsky@upjs.sk [Department of Biophysics, Institute of Physics, P.J. Šafárik University in Košice, Jesenná 5, 040 01 Košice (Slovakia)

    2016-03-22

    Population heterogeneity plays an important role across many research, as well as the real-world, problems. The population heterogeneity relates to the ability of a population to cope with an environment change (or uncertainty) preventing its extinction. However, this ability is not always desirable as can be exemplified by an intratumor heterogeneity which positively correlates with the development of resistance to therapy. Causation of population heterogeneity is therefore in biology and medicine an intensively studied topic. In this paper the evolution of a specific strategy of population diversification, the phenotype switching, is studied at a conceptual level. The presented simulation model studies evolution of a large population of asexual organisms in a time-varying environment represented by a stochastic Markov process. Each organism disposes with a stochastic or nonlinear deterministic switching strategy realized by discrete-time models with evolvable parameters. We demonstrate that under rapidly varying exogenous conditions organisms operate in the vicinity of the bet-hedging strategy, while the deterministic patterns become relevant as the environmental variations are less frequent. Statistical characterization of the steady state regimes of the populations is done using the Hellinger and Kullback–Leibler functional distances and the Hamming distance. - Highlights: • Relation between phenotype switching and environment is studied. • The Markov chain Monte Carlo based model is developed. • Stochastic and deterministic strategies of phenotype switching are utilized. • Statistical measures of the dynamic heterogeneity reveal universal properties. • The results extend to higher lattice dimensions.

  16. Study of selected phenotype switching strategies in time varying environment

    International Nuclear Information System (INIS)

    Horvath, Denis; Brutovsky, Branislav

    2016-01-01

    Population heterogeneity plays an important role across many research, as well as the real-world, problems. The population heterogeneity relates to the ability of a population to cope with an environment change (or uncertainty) preventing its extinction. However, this ability is not always desirable as can be exemplified by an intratumor heterogeneity which positively correlates with the development of resistance to therapy. Causation of population heterogeneity is therefore in biology and medicine an intensively studied topic. In this paper the evolution of a specific strategy of population diversification, the phenotype switching, is studied at a conceptual level. The presented simulation model studies evolution of a large population of asexual organisms in a time-varying environment represented by a stochastic Markov process. Each organism disposes with a stochastic or nonlinear deterministic switching strategy realized by discrete-time models with evolvable parameters. We demonstrate that under rapidly varying exogenous conditions organisms operate in the vicinity of the bet-hedging strategy, while the deterministic patterns become relevant as the environmental variations are less frequent. Statistical characterization of the steady state regimes of the populations is done using the Hellinger and Kullback–Leibler functional distances and the Hamming distance. - Highlights: • Relation between phenotype switching and environment is studied. • The Markov chain Monte Carlo based model is developed. • Stochastic and deterministic strategies of phenotype switching are utilized. • Statistical measures of the dynamic heterogeneity reveal universal properties. • The results extend to higher lattice dimensions.

  17. Quantum Capacity under Adversarial Quantum Noise: Arbitrarily Varying Quantum Channels

    Science.gov (United States)

    Ahlswede, Rudolf; Bjelaković, Igor; Boche, Holger; Nötzel, Janis

    2013-01-01

    We investigate entanglement transmission over an unknown channel in the presence of a third party (called the adversary), which is enabled to choose the channel from a given set of memoryless but non-stationary channels without informing the legitimate sender and receiver about the particular choice that he made. This channel model is called an arbitrarily varying quantum channel (AVQC). We derive a quantum version of Ahlswede's dichotomy for classical arbitrarily varying channels. This includes a regularized formula for the common randomness-assisted capacity for entanglement transmission of an AVQC. Quite surprisingly and in contrast to the classical analog of the problem involving the maximal and average error probability, we find that the capacity for entanglement transmission of an AVQC always equals its strong subspace transmission capacity. These results are accompanied by different notions of symmetrizability (zero-capacity conditions) as well as by conditions for an AVQC to have a capacity described by a single-letter formula. In the final part of the paper the capacity of the erasure-AVQC is computed and some light shed on the connection between AVQCs and zero-error capacities. Additionally, we show by entirely elementary and operational arguments motivated by the theory of AVQCs that the quantum, classical, and entanglement-assisted zero-error capacities of quantum channels are generically zero and are discontinuous at every positivity point.

  18. Genome-wide DNA polymorphism analyses using VariScan

    Directory of Open Access Journals (Sweden)

    Vilella Albert J

    2006-09-01

    Full Text Available Abstract Background DNA sequence polymorphisms analysis can provide valuable information on the evolutionary forces shaping nucleotide variation, and provides an insight into the functional significance of genomic regions. The recent ongoing genome projects will radically improve our capabilities to detect specific genomic regions shaped by natural selection. Current available methods and software, however, are unsatisfactory for such genome-wide analysis. Results We have developed methods for the analysis of DNA sequence polymorphisms at the genome-wide scale. These methods, which have been tested on a coalescent-simulated and actual data files from mouse and human, have been implemented in the VariScan software package version 2.0. Additionally, we have also incorporated a graphical-user interface. The main features of this software are: i exhaustive population-genetic analyses including those based on the coalescent theory; ii analysis adapted to the shallow data generated by the high-throughput genome projects; iii use of genome annotations to conduct a comprehensive analyses separately for different functional regions; iv identification of relevant genomic regions by the sliding-window and wavelet-multiresolution approaches; v visualization of the results integrated with current genome annotations in commonly available genome browsers. Conclusion VariScan is a powerful and flexible suite of software for the analysis of DNA polymorphisms. The current version implements new algorithms, methods, and capabilities, providing an important tool for an exhaustive exploratory analysis of genome-wide DNA polymorphism data.

  19. Neutron fluctuations in a medium randomly varying in time

    Energy Technology Data Exchange (ETDEWEB)

    Lenard, Pal [KFKI Atomic Energy Research Institute, Budapest (Hungary); Imre, Pazsit [Chalmers Univ. of Technology, Dept. of Nuclear Engineering, SE, Goteborg (Sweden)

    2005-07-01

    The master equation approach, which has traditionally been used for the calculation of neutron fluctuations in zero power systems with constant parameters, is extended to a case when the parameters of the system change randomly in time. We consider a forward type master equation for the probability distribution of the number of particles in a multiplying system whose properties jump randomly between two discrete states, both with and without an external source. The first two factorial moments are calculated, including the covariance. This model can be considered the unification of stochastic methods that were used either in a constant multiplying medium via the master equation technique, or in a fluctuating medium via the Langevin technique. In contrast to these methods, the one presented here can calculate the inherent noise in time-varying systems. The results obtained show a much richer characteristics of the zero power noise than that in constant systems. Even the concept of criticality has to be given a probabilistic interpretation. The asymptotic behaviour of the variance will be also qualitatively different from that in constant systems. The covariance of the neutron number in a subcritical system with a source, and the corresponding power spectrum, shows both the inherent and parametrically induced noise components. The results are relevant in medium power subcritical systems where the zero power noise is still significant, but they also have a bearing on all types of branching processes, such as evolution of biological systems, spreading of epidemics etc., which are set in a time-varying environment. (authors)

  20. Neutron fluctuations in a medium randomly varying in time

    International Nuclear Information System (INIS)

    Lenard, Pal; Imre, Pazsit

    2005-01-01

    The master equation approach, which has traditionally been used for the calculation of neutron fluctuations in zero power systems with constant parameters, is extended to a case when the parameters of the system change randomly in time. We consider a forward type master equation for the probability distribution of the number of particles in a multiplying system whose properties jump randomly between two discrete states, both with and without an external source. The first two factorial moments are calculated, including the covariance. This model can be considered the unification of stochastic methods that were used either in a constant multiplying medium via the master equation technique, or in a fluctuating medium via the Langevin technique. In contrast to these methods, the one presented here can calculate the inherent noise in time-varying systems. The results obtained show a much richer characteristics of the zero power noise than that in constant systems. Even the concept of criticality has to be given a probabilistic interpretation. The asymptotic behaviour of the variance will be also qualitatively different from that in constant systems. The covariance of the neutron number in a subcritical system with a source, and the corresponding power spectrum, shows both the inherent and parametrically induced noise components. The results are relevant in medium power subcritical systems where the zero power noise is still significant, but they also have a bearing on all types of branching processes, such as evolution of biological systems, spreading of epidemics etc., which are set in a time-varying environment. (authors)