Science.gov

Sample records for realistic delivery conditions

  1. Synchronized moving aperture radiation therapy (SMART): superimposing tumor motion on IMRT MLC leaf sequences under realistic delivery conditions

    NASA Astrophysics Data System (ADS)

    Xu, Jun; Papanikolaou, Nikos; Shi, Chengyu; Jiang, Steve B.

    2009-08-01

    Synchronized moving aperture radiation therapy (SMART) has been proposed to account for tumor motions during radiotherapy in prior work. The basic idea of SMART is to synchronize the moving radiation beam aperture formed by a dynamic multileaf collimator (DMLC) with the tumor motion induced by respiration. In this paper, a two-dimensional (2D) superimposing leaf sequencing method is presented for SMART. A leaf sequence optimization strategy was generated to assure the SMART delivery under realistic delivery conditions. The study of delivery performance using the Varian LINAC and the Millennium DMLC showed that clinical factors such as collimator angle, dose rate, initial phase and machine tolerance affect the delivery accuracy and efficiency. An in-house leaf sequencing software was developed to implement the 2D superimposing leaf sequencing method and optimize the motion-corrected leaf sequence under realistic clinical conditions. The analysis of dynamic log (Dynalog) files showed that optimization of the leaf sequence for various clinical factors can avoid beam hold-offs which break the synchronization of SMART and fail the SMART dose delivery. Through comparison between the simulated delivered fluence map and the planed fluence map, it was shown that the motion-corrected leaf sequence can greatly reduce the dose error.

  2. Performance of Airborne Precision Spacing Under Realistic Wind Conditions

    NASA Technical Reports Server (NTRS)

    Wieland, Frederick; Santos, Michel; Krueger, William; Houston, Vincent E.

    2011-01-01

    With the expected worldwide increase of air traffic during the coming decade, both the Federal Aviation Administration s (FAA s) Next Generation Air Transportation System (NextGen), as well as Eurocontrol s Single European Sky ATM Research (SESAR) program have, as part of their plans, air traffic management solutions that can increase performance without requiring time-consuming and expensive infrastructure changes. One such solution involves the ability of both controllers and flight crews to deliver aircraft to the runway with greater accuracy than is possible today. Previous research has shown that time-based spacing techniques, wherein the controller assigns a time spacing to each pair of arriving aircraft, is one way to achieve this goal by providing greater runway delivery accuracy that produces a concomitant increase in system-wide performance. The research described herein focuses on a specific application of time-based spacing, called Airborne Precision Spacing (APS), which has evolved over the past ten years. This research furthers APS understanding by studying its performance with realistic wind conditions obtained from atmospheric sounding data and with realistic wind forecasts obtained from the Rapid Update Cycle (RUC) short-range weather forecast. In addition, this study investigates APS performance with limited surveillance range, as provided by the Automatic Dependent Surveillance-Broadcast (ADS-B) system, and with an algorithm designed to improve APS performance when an ADS-B signal is unavailable. The results presented herein quantify the runway threshold delivery accuracy of APS un-der these conditions, and also quantify resulting workload metrics such as the number of speed changes required to maintain spacing.

  3. Foreword: In situ gas surface interactions: approaching realistic conditions

    NASA Astrophysics Data System (ADS)

    Lundgren, Edvin; Over, Herbert

    2008-03-01

    This special issue is devoted to the application of in situ surface-sensitive techniques in the elucidation of catalysed reactions at (model) catalyst surfaces. Both reaction intermediates and the nature of the catalytically active phase are the targets of these investigations. In situ surface science techniques are also used to study the interaction of water with surfaces under realistic conditions. Since 80% of all technical chemicals are manufactured by utilizing (heterogeneous) catalysis, scientific understanding and technological development of catalysis are of central practical importance in modern society [1]. Heterogeneously catalysed reactions take place at the gas/solid interface. Therefore one of the major topics in surface chemistry and physics is closely related to heterogeneous catalysis, with the aim of developing novel catalysts and to improve catalysts' performances on the basis of atomic scale based knowledge. Despite the economical and environmental rewards—if such a goal is achieved—and despite 40 years of intensive research, practical catalysis is still safely in a black box: the reactivity and selectivity of a catalyst are commercially still optimized on a trial and error basis, applying the high throughput screening approach. The reason for this discrepancy between ambition and reality lies in the inherent complexity of the catalytic system, consisting of the working catalyst and the interaction of the catalyst with the reactant mixture. Practical (solid) catalysts consist of metal or oxide nanoparticles which are dispersed and stabilized on a support and which may be promoted by means of additives. These particles catalyse a reaction in pressures as high as 100 bar. Practical catalysis is in general considered to be far too complex for gaining atomic-scale understanding of the mechanism of the catalysed reaction of an industrial catalyst during its operation. Therefore it has been necessary to introduce idealization and simplification of

  4. Foreword: In situ gas surface interactions: approaching realistic conditions

    NASA Astrophysics Data System (ADS)

    Lundgren, Edvin; Over, Herbert

    2008-03-01

    This special issue is devoted to the application of in situ surface-sensitive techniques in the elucidation of catalysed reactions at (model) catalyst surfaces. Both reaction intermediates and the nature of the catalytically active phase are the targets of these investigations. In situ surface science techniques are also used to study the interaction of water with surfaces under realistic conditions. Since 80% of all technical chemicals are manufactured by utilizing (heterogeneous) catalysis, scientific understanding and technological development of catalysis are of central practical importance in modern society [1]. Heterogeneously catalysed reactions take place at the gas/solid interface. Therefore one of the major topics in surface chemistry and physics is closely related to heterogeneous catalysis, with the aim of developing novel catalysts and to improve catalysts' performances on the basis of atomic scale based knowledge. Despite the economical and environmental rewards—if such a goal is achieved—and despite 40 years of intensive research, practical catalysis is still safely in a black box: the reactivity and selectivity of a catalyst are commercially still optimized on a trial and error basis, applying the high throughput screening approach. The reason for this discrepancy between ambition and reality lies in the inherent complexity of the catalytic system, consisting of the working catalyst and the interaction of the catalyst with the reactant mixture. Practical (solid) catalysts consist of metal or oxide nanoparticles which are dispersed and stabilized on a support and which may be promoted by means of additives. These particles catalyse a reaction in pressures as high as 100 bar. Practical catalysis is in general considered to be far too complex for gaining atomic-scale understanding of the mechanism of the catalysed reaction of an industrial catalyst during its operation. Therefore it has been necessary to introduce idealization and simplification of

  5. Boundary conditions towards realistic simulation of jet engine noise

    NASA Astrophysics Data System (ADS)

    Dhamankar, Nitin S.

    Strict noise regulations at major airports and increasing environmental concerns have made prediction and attenuation of jet noise an active research topic. Large eddy simulation coupled with computational aeroacoustics has the potential to be a significant research tool for this problem. With the emergence of petascale computer clusters, it is now computationally feasible to include the nozzle geometry in jet noise simulations. In high Reynolds number experiments on jet noise, the turbulent boundary layer on the inner surface of the nozzle separates into a turbulent free shear layer. Inclusion of a nozzle with turbulent inlet conditions is necessary to simulate this phenomenon realistically. This will allow a reasonable comparison of numerically computed noise levels with the experimental results. Two viscous wall boundary conditions are implemented for modeling the nozzle walls. A characteristic-based approach is compared with a computationally cheaper, extrapolation-based formulation. In viscous flow over a circular cylinder under two different regimes, excellent agreement is observed between the results of the two approaches. The results agree reasonably well with reference experimental and numerical results. Both the boundary conditions are thus found to be appropriate, the extrapolation-based formulation having an edge with its low cost. This is followed with the crucial step of generation of a turbulent boundary layer inside the nozzle. A digital filter-based turbulent inflow condition, extended in a new way to non-uniform curvilinear grids is implemented to achieve this. A zero pressure gradient flat plate turbulent boundary layer is simulated at a high Reynolds number to show that the method is capable of producing sustained turbulence. The length of the adjustment region necessary for synthetic inlet turbulence to recover from modeling errors is estimated. A low Reynolds number jet simulation including a round nozzle geometry is performed and the method

  6. Lactic acid bacteria as mucosal delivery vehicles: a realistic therapeutic option.

    PubMed

    Wang, Miao; Gao, Zeqian; Zhang, Yongguang; Pan, Li

    2016-07-01

    Recombinant lactic acid bacteria (LAB), in particular lactococci and lactobacilli, have gained increasing interest as mucosal delivery vehicles in recent years. With the development of mucosal vaccines, studies on LAB expression systems have been mainly focused on the generation of genetic tools for antigen expression in different locations. Recombinant LAB show advantages in a wide range of aspects over other mucosal delivery systems and represent an attractive candidate for the delivery of therapeutic and prophylactic molecules in different applications. Here, we review the recent data on the use of recombinant LAB as mucosal delivery vectors and the associated health benefits, including the prevention and treatment of inflammatory bowel diseases (IBDs), autoimmune disorders, and infections by pathogenic microorganisms from mucosal surfaces. In addition, we discuss the use of LAB as vehicles to deliver DNA directly to eukaryotic cells. Researches from the last 5 years demonstrate that LAB as vectors for mucosal delivery of therapeutic molecules seem to be a realistic therapeutic option both in human and animal diseases. PMID:27154346

  7. Performance of Airborne Precision Spacing Under Realistic Wind Conditions and Limited Surveillance Range

    NASA Technical Reports Server (NTRS)

    Wieland, Frederick; Santos, Michel; Krueger, William; Houston, Vincent E.

    2011-01-01

    With the expected worldwide increase of air traffic during the coming decade, both the Federal Aviation Administration's (FAA's) Next Generation Air Transportation System (NextGen), as well as Eurocontrol's Single European Sky ATM Research (SESAR) program have, as part of their plans, air traffic management (ATM) solutions that can increase performance without requiring time-consuming and expensive infrastructure changes. One such solution involves the ability of both controllers and flight crews to deliver aircraft to the runway with greater accuracy than they can today. Previous research has shown that time-based spacing techniques, wherein the controller assigns a time spacing to each pair of arriving aircraft, can achieve this goal by providing greater runway delivery accuracy and producing a concomitant increase in system-wide performance. The research described herein focuses on one specific application of time-based spacing, called Airborne Precision Spacing (APS), which has evolved over the past ten years. This research furthers APS understanding by studying its performance with realistic wind conditions obtained from atmospheric sounding data and with realistic wind forecasts obtained from the Rapid Update Cycle (RUC) short-range weather forecast. In addition, this study investigates APS performance with limited surveillance range, as provided by the Automatic Dependent Surveillance-Broadcast (ADS-B) system, and with an algorithm designed to improve APS performance when ADS-B surveillance data is unavailable. The results presented herein quantify the runway threshold delivery accuracy of APS under these conditions, and also quantify resulting workload metrics such as the number of speed changes required to maintain spacing.

  8. Simulating Realistic Imaging Conditions For In-Situ Liquid Microscopy

    PubMed Central

    Welch, David A.; Faller, Roland; Evans, James E.; Browning, Nigel D.

    2013-01-01

    In situ transmission electron microscopy enables the imaging of biological cells, macromolecular protein complexes, nanoparticles, and other systems in a near-native environment. In order to improve interpretation of image contrast features and also predict ideal imaging conditions ahead of time, new virtual electron microscopic techniques are needed. A technique for virtual fluid-stage high-angle annular dark-field scanning transmission electron microscopy with the multislice method is presented that enables the virtual imaging of model fluid-stage systems composed of millions of atoms. The virtual technique is exemplified by simulating images of PbS nanoparticles under different imaging conditions and the results agree with previous experimental findings. General insight is obtained on the influence of the effects of fluid path length, membrane thickness, nanoparticle position, defocus and other microscope parameters on attainable image quality. PMID:23872040

  9. Simulating realistic imaging conditions for in situ liquid microscopy

    SciTech Connect

    Welch, David A.; Faller, Roland; Evans, James E.; Browning, Nigel D.

    2013-12-01

    In situ transmission electron microscopy enables the imaging of biological cells, macromolecular protein complexes, nanoparticles, and other systems in a near-native environment. In order to improve interpretation of image contrast features and also predict ideal imaging conditions ahead of time, new virtual electron microscopic techniques are needed. A technique for virtual fluid-stage high-angle annular dark-field scanning transmission electron microscopy with the multislice method is presented that enables the virtual imaging of model fluid-stage systems composed of millions of atoms. The virtual technique is exemplified by simulating images of PbS nanoparticles under different imaging conditions and the results agree with previous experimental findings. General insight is obtained on the influence of the effects of fluid path length, membrane thickness, nanoparticle position, defocus and other microscope parameters on attainable image quality.

  10. Stereoselective Syntheses of Pentose Sugars Under Realistic Prebiotic Conditions

    NASA Astrophysics Data System (ADS)

    Pizzarello, Sandra; Weber, Arthur L.

    2010-02-01

    Glycolaldehyde and dl-glyceraldehyde reacted in a water-buffered solution under mildly acidic conditions and in the presence of chiral dipeptide catalysts produced pentose sugars whose configuration is affected by the chirality of the catalyst. The chiral effect was found to vary between catalysts and to be largest for di-valine. Lyxose, arabinose, ribose and xylose are formed in different amounts, whose relative proportions do not change significantly with the varying of conditions. With LL-peptide catalysts, ribose was the only pentose sugar to have a significant D-enantiomeric excess ( ee) (≤44%), lyxose displayed an L- ee of ≤66%, arabinose a smaller L- ee of ≤8%, and xylose was about racemic. These data expand our previous findings for tetrose sugars and further substantiate the suggestion that interactions between simple molecules of prebiotic relevance on the early Earth might have included the transfer of chiral asymmetry and advanced molecular evolution.

  11. FORMATION OF TERRESTRIAL PLANETS FROM PROTOPLANETS UNDER A REALISTIC ACCRETION CONDITION

    SciTech Connect

    Kokubo, Eiichiro; Genda, Hidenori E-mail: genda@geo.titech.ac.jp

    2010-05-01

    The final stage of terrestrial planet formation is known as the giant impact stage where protoplanets collide with one another to form planets. So far this stage has been mainly investigated by N-body simulations with an assumption of perfect accretion in which all collisions lead to accretion. However, this assumption breaks for collisions with high velocity and/or a large impact parameter. We derive an accretion condition for protoplanet collisions in terms of impact velocity and angle and masses of colliding bodies, from the results of numerical collision experiments. For the first time, we adopt this realistic accretion condition in N-body simulations of terrestrial planet formation from protoplanets. We compare the results with those with perfect accretion and show how the accretion condition affects terrestrial planet formation. We find that in the realistic accretion model about half of collisions do not lead to accretion. However, the final number, mass, orbital elements, and even growth timescale of planets are barely affected by the accretion condition. For the standard protoplanetary disk model, typically two Earth-sized planets form in the terrestrial planet region over about 10{sup 8} yr in both realistic and perfect accretion models. We also find that for the realistic accretion model, the spin angular velocity is about 30% smaller than that for the perfect accretion model, which is as large as the critical spin angular velocity for rotational instability. The spin angular velocity and obliquity obey Gaussian and isotropic distributions, respectively, independently of the accretion condition.

  12. Use of a realistic breathing lung phantom to evaluate dose delivery errors

    SciTech Connect

    Court, Laurence E.; Seco, Joao; Lu Xingqi; Ebe, Kazuyu; Mayo, Charles; Ionascu, Dan; Winey, Brian; Giakoumakis, Nikos; Aristophanous, Michalis; Berbeco, Ross; Rottman, Joerg; Bogdanov, Madeleine; Schofield, Deborah; Lingos, Tania

    2010-11-15

    Purpose: To compare the effect of respiration-induced motion on delivered dose (the interplay effect) for different treatment techniques under realistic clinical conditions. Methods: A flexible resin tumor model was created using rapid prototyping techniques based on a computed tomography (CT) image of an actual tumor. Twenty micro-MOSFETs were inserted into the tumor model and the tumor model was inserted into an anthropomorphic breathing phantom. Phantom motion was programed using the motion trajectory of an actual patient. A four-dimensional CT image was obtained and several treatment plans were created using different treatment techniques and planning systems: Conformal (Eclipse), step-and-shoot intensity-modulated radiation therapy (IMRT) (Pinnacle), step-and-shoot IMRT (XiO), dynamic IMRT (Eclipse), complex dynamic IMRT (Eclipse), hybrid IMRT [60% conformal, 40% dynamic IMRT (Eclipse)], volume-modulated arc therapy (VMAT) [single-arc (Eclipse)], VMAT [double-arc (Eclipse)], and complex VMAT (Eclipse). The complex plans were created by artificially pushing the optimizer to give complex multileaf collimator sequences. Each IMRT field was irradiated five times and each VMAT field was irradiated ten times, with each irradiation starting at a random point in the respiratory cycle. The effect of fractionation was calculated by randomly summing the measured doses. The maximum deviation for each measurement point per fraction and the probability that 95% of the model tumor had dose deviations less than 2% and 5% were calculated as a function of the number of fractions. Tumor control probabilities for each treatment plan were calculated and compared. Results: After five fractions, measured dose deviations were less than 2% for more than 95% of measurement points within the tumor model for all plans, except the complex dynamic IMRT, step-and-shoot IMRT (XiO), complex VMAT, and single-arc VMAT plans. Reducing the dose rate of the complex IMRT plans from 600 to 200 MU

  13. An additional condition for Bell experiments for accepting local realistic theories

    NASA Astrophysics Data System (ADS)

    Nagata, Koji; Nakamura, Tadao

    2013-12-01

    We assume that one source of two uncorrelated spin-carrying particles emits them in a state, which can be described as a spin-1/2 bipartite pure uncorrelated state. We consider a Bell-Clauser-Horne-Shimony-Holt (Bell-CHSH) experiment with two-orthogonal-settings. We propose an additional condition for the state to be reproducible by the property of local realistic theories. We use the proposed measurement theory in order to construct the additional condition (Nagata and Nakamura in Int J Theor Phys 49:162, 2010). The condition is that local measurement outcome is . Otherwise, such an experiment does not allow for the existence of local realistic theories even in the situation that all Bell-CHSH inequalities hold. Also we derive new set of Bell inequalities when local measurement outcome is.

  14. 48 CFR 552.270-17 - Delivery and Condition.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Delivery and Condition. 552.270-17 Section 552.270-17 Federal Acquisition Regulations System GENERAL SERVICES ADMINISTRATION... Delivery and Condition. As prescribed in 570.603, insert the following clause: Delivery and Condition...

  15. Simulation Evaluation of Controller-Managed Spacing Tools under Realistic Operational Conditions

    NASA Technical Reports Server (NTRS)

    Callantine, Todd J.; Hunt, Sarah M.; Prevot, Thomas

    2014-01-01

    Controller-Managed Spacing (CMS) tools have been developed to aid air traffic controllers in managing high volumes of arriving aircraft according to a schedule while enabling them to fly efficient descent profiles. The CMS tools are undergoing refinement in preparation for field demonstration as part of NASA's Air Traffic Management (ATM) Technology Demonstration-1 (ATD-1). System-level ATD-1 simulations have been conducted to quantify expected efficiency and capacity gains under realistic operational conditions. This paper presents simulation results with a focus on CMS-tool human factors. The results suggest experienced controllers new to the tools find them acceptable and can use them effectively in ATD-1 operations.

  16. Numerical investigation of aerosolized drug delivery in the human lungs under mechanical ventilator conditions

    NASA Astrophysics Data System (ADS)

    Vanrhein, Timothy; Banerjee, Arindam

    2010-11-01

    Particle deposition for aerosolized drug delivery in the human airways is heavily dependent upon flow conditions. Numerical modeling techniques have proven valuable for determining particle deposition characteristics under steady flow conditions. For the case of patients under mechanical ventilation, however, flow conditions change drastically and there is an increased importance to understand particle deposition characteristics. This study focuses on mechanically ventilated conditions in the upper trachea-bronchial (TB) region of the human airways. Solution of the continuous phase flow is done under ventilator waveform conditions with a suitable turbulence model in conjunction with a realistic model of upper TB airways. A discrete phase Euler-Lagrange approach is applied to solve for particle deposition characteristics with a focus on the effect of the ventilator inlet waveform. The purpose of this study is to accurately model flow conditions in the upper TB airways under mechanically ventilated conditions with a focus on real-time patient specific targeted aerosolized drug delivery.

  17. Simple computer program to model 3-dimensional underground heat flow with realistic boundary conditions

    NASA Astrophysics Data System (ADS)

    Metz, P. D.

    A FORTRAN computer program called GROCS (GRound Coupled Systems) has been developed to study 3-dimensional underground heat flow. Features include the use of up to 30 finite elements or blocks of Earth which interact via finite difference heat flow equations and a subprogram which sets realistic time and depth dependent boundary conditions. No explicit consideration of mositure movement or freezing is given. GROCS has been used to model the thermal behavior of buried solar heat storage tanks (with and without insulation) and serpentine pipe fields for solar heat pump space conditioning systems. The program is available independently or in a form compatible with specially written TRNSYS component TYPE subroutines. The approach taken in the design of GROCS, the mathematics contained and the program architecture, are described. Then, the operation of the stand-alone version is explained. Finally, the validity of GROCS is discussed.

  18. Conditions for production of interdisciplinary teamwork outcomes in oncology teams: protocol for a realist evaluation

    PubMed Central

    2014-01-01

    Background Interdisciplinary teamwork (ITW) is designed to promote the active participation of several disciplines in delivering comprehensive cancer care to patients. ITW provides mechanisms to support continuous communication among care providers, optimize professionals’ participation in clinical decision-making within and across disciplines, and foster care coordination along the cancer trajectory. However, ITW mechanisms are not activated optimally by all teams, resulting in a gap between desired outcomes of ITW and actual outcomes observed. The aim of the present study is to identify the conditions underlying outcome production by ITW in local oncology teams. Methods This retrospective multiple case study will draw upon realist evaluation principles to explore associations among context, mechanisms and outcomes (CMO). The cases are nine interdisciplinary cancer teams that participated in a previous study evaluating ITW outcomes. Qualitative data sources will be used to construct a picture of CMO associations in each case. For data collection, reflexive focus groups will be held to capture patients’ and professionals’ perspectives on ITW, using the guiding question, ‘What works, for whom, and under what circumstances?’ Intra-case analysis will be used to trace associations between context, ITW mechanisms, and patient outcomes. Inter-case analysis will be used to compare the different cases’ CMO associations for a better understanding of the phenomenon under study. Discussion This multiple case study will use realist evaluation principles to draw lessons about how certain contexts are more or less likely to produce particular outcomes. The results will make it possible to target more specifically the actions required to optimize structures and to activate the best mechanisms to meet the needs of cancer patients. This project could also contribute significantly to the development of improved research methods for conducting realist evaluations of

  19. Deriving realistic source boundary conditions for a CFD simulation of concentrations in workroom air.

    PubMed

    Feigley, Charles E; Do, Thanh H; Khan, Jamil; Lee, Emily; Schnaufer, Nicholas D; Salzberg, Deborah C

    2011-05-01

    Computational fluid dynamics (CFD) is used increasingly to simulate the distribution of airborne contaminants in enclosed spaces for exposure assessment and control, but the importance of realistic boundary conditions is often not fully appreciated. In a workroom for manufacturing capacitors, full-shift samples for isoamyl acetate (IAA) were collected for 3 days at 16 locations, and velocities were measured at supply grills and at various points near the source. Then, velocity and concentration fields were simulated by 3-dimensional steady-state CFD using 295K tetrahedral cells, the k-ε turbulence model, standard wall function, and convergence criteria of 10(-6) for all scalars. Here, we demonstrate the need to represent boundary conditions accurately, especially emission characteristics at the contaminant source, and to obtain good agreement between observations and CFD results. Emission rates for each day were determined from six concentrations measured in the near field and one upwind using an IAA mass balance. The emission was initially represented as undiluted IAA vapor, but the concentrations estimated using CFD differed greatly from the measured concentrations. A second set of simulations was performed using the same IAA emission rates but a more realistic representation of the source. This yielded good agreement with measured values. Paying particular attention to the region with highest worker exposure potential-within 1.3 m of the source center-the air speed and IAA concentrations estimated by CFD were not significantly different from the measured values (P = 0.92 and P = 0.67, respectively). Thus, careful consideration of source boundary conditions greatly improved agreement with the measured values. PMID:21422277

  20. Dynamic fluid loss in hydraulic fracturing under realistic shear conditions in high-permeability rocks

    SciTech Connect

    Navarrete, R.C.; Cawiezel, K.E.; Constien, V.G.

    1996-08-01

    A study of the dynamic fluid loss of hydraulic fracturing fluids under realistic shear conditions is presented. During a hydraulic fracturing treatment, a polymeric solution is pumped under pressure down the well to create and propagate a fracture. Part of the fluid leaks into the rock formation, leaving a skin layer of polymer or polymer filter cake, at the rock surface or in the pore space. This study focuses on the effects of shear rate and permeability on dynamic fluid-loss behavior of crosslinked and linear fracturing gels. Previous studies of dynamic fluid loss have mainly been with low-permeability cores and constant shear rates. Here, the effect of shear history and fluid-loss additive on the dynamic leakoff of high-permeability cores is examined.

  1. Blood brain barrier: An overview on strategies in drug delivery, realistic in vitro modeling and in vivo live tracking.

    PubMed

    Pandey, Pawan Kumar; Sharma, Ashok Kumar; Gupta, Umesh

    2016-01-01

    Blood brain barrier (BBB) is a group of astrocytes, neurons and endothelial cells, which makes restricted passage of various biological or chemical entities to the brain tissue. It gives protection to brain at one hand, but at the other hand it has very selective permeability for bio-actives and other foreign materials and is one of the major challenges for the drug delivery. Nanocarriers are promising to cross BBB utilizing alternative route of administration such as intranasal and intra-carotid drug delivery which bypasses BBB. In future more optimized drug delivery system can be achieved by compiling the best routes with the best carriers. Single photon emission tomography (SPECT) and different brain-on-a-chip in vitro models are being very reliable to study live in vivo tracking of BBB and its pathophysiology, respectively. In the current review we have tried to exploit mechanistically all these to understand and manage the various BBB disruptions in diseased condition along with crossing the hurdles occurring in drug or gene delivery across BBB. PMID:27141418

  2. Can low energy electrons lead to strand breaks in DNA under realistic conditions?

    NASA Astrophysics Data System (ADS)

    Kohanoff, Jorge; Smyth, Maeve

    2012-02-01

    It is widely accepted that low energy electrons produced by ionizing radiation play an important role in causing DNA damage [B. Bouda"iffa et al., Science 287, 1658 (2000)]. Understanding the behaviour of DNA components in the condensed phase due to such electrons is a fundamental step towards modelling this damage within a realistic environment. Here we present a computational study of the effect of low energy electrons in condensed phase models of solvated DNA fragments. First we show that excess electrons, which are initially found delocalized, quickly localize around the nucleobases within a 15 fs time scale. Energies and time scales are comparable for each of the bases [M. Smyth and J. Kohanoff, Phys. Rev. Lett. 106, 238108 (2011)]. The phosphodiester bond C3'-O3', which under normal conditions is very stable, weakens significantly upon electron attachment both, in the gas and in the condensed phase. Computation of free energy profiles show that barriers for bond cleavage are in the region of 5-8 kcal/mol for all the solvated nucleotides, thus suggesting that this kind of event is quite likely at ambient temperature. This supports the notion that ionizing radiation can actually lead to DNA strand breaks in the physiological environment.

  3. Understanding the motivation and performance of community health volunteers involved in the delivery of health programmes in Kampala, Uganda: a realist evaluation

    PubMed Central

    Vareilles, Gaëlle; Marchal, Bruno; Kane, Sumit; Petrič, Taja; Pictet, Gabriel; Pommier, Jeanine

    2015-01-01

    Objectives This paper presents the results of a realist evaluation that aimed to understand how, why and under what circumstances a Red Cross (RC) capacity-building intervention influences the motivation and the performance of RC community health volunteers involved in the delivery of an immunisation programme in Kampala, Uganda. Method Given the complexity of the intervention, we adopted realist evaluation as our methodological approach and the case study as our study design. Data collection included document review, participant observation and interviews. The constant comparative method was used for the analysis. Two contrasted cases were selected within the five Kampala districts. Each case covers the management of the immunisation programme implemented at a RC branch. In each case, a programme manager and 15 RC volunteers were interviewed. The selection of the volunteers was purposive. Results We found that a capacity-building programme including supervision supportive of autonomy, skills and knowledge enhancement, and adapted to the different subgroups of volunteers, leads to satisfaction of the three key drivers of volunteer motivation: feelings of autonomy, competence and connectedness. This contributes to higher retention, and better task performance and well-being among the volunteers. Enabling contextual conditions include the responsiveness of the Uganda Red Cross Society (URCS) to community needs, and recognition of the work of the volunteers, from the URCS and the community. Conclusions A management approach that caters for the different motivational states and changing needs of the volunteers will lead to better performance. The findings will inform not only the management of community health volunteers, but also the management of all kinds of health workers. PMID:26525721

  4. A comparison of spent fuel shipping cask response to 10 CFR 71 normal conditions and realistic hot day extremes

    SciTech Connect

    Manson, S.J.; Gianoulakis, S.E.

    1994-04-01

    An examination of the effect of a realistic (though conservative) hot day environment on the thermal transient behavior of spent fuel shipping casks is made. These results are compared to those that develop under the prescribed normal thermal condition of 10 CFR 71. Of specific concern are the characteristics of propagating thermal waves, which are set up by diurnal variations of temperature and insolation in the outdoor environment. In order to arrive at a realistic approximation of these variations on a conservative hot day, actual temperature and insolation measurements have been obtained from the National Climatic Data Center (NCDC) for representatively hot and high heat flux days. Thus, the use of authentic meteorological data ensures the realistic approach sought. Further supporting the desired realism of the modeling effort is the use of realistic cask configurations in which multiple laminations of structural, shielding, and other materials are expected to attenuate the propagating thermal waves. The completed analysis revealed that the majority of wall temperatures, for a wide variety of spent fuel shipping cask configurations, fall well below those predicted by enforcement of the regulatory environmental conditions of 10 CFR 71. It was found that maximum temperatures at the cask surface occasionally lie above temperatures predicted under the prescribed regulatory conditions. However, the temperature differences are small enough that the normal conservative assumptions that are made in the course of typical cask evaluations should correct for any potential violations. The analysis demonstrates that diurnal temperature variations that penetrate the cask wall all have maxima substantially less than the corresponding regulatory solutions. Therefore it is certain that vital cask components and the spent fuel itself will not exceed the temperatures calculated by use of the conditions of 10 CFR 71.

  5. The NetVISA automatic association tool. Next generation software testing and performance under realistic conditions.

    NASA Astrophysics Data System (ADS)

    Le Bras, Ronan; Arora, Nimar; Kushida, Noriyuki; Tomuta, Elena; Kebede, Fekadu; Feitio, Paulino

    2016-04-01

    The CTBTO's International Data Centre is in the process of developing the next generation software to perform the automatic association step. The NetVISA software uses a Bayesian approach with a forward physical model using probabilistic representations of the propagation, station capabilities, background seismicity, noise detection statistics, and coda phase statistics. The software has been in development for a few years and is now reaching the stage where it is being tested in a realistic operational context. An interactive module has been developed where the NetVISA automatic events that are in addition to the Global Association (GA) results are presented to the analysts. We report on a series of tests where the results are examined and evaluated by seasoned analysts. Consistent with the statistics previously reported (Arora et al., 2013), the first test shows that the software is able to enhance analysis work by providing additional event hypothesis for consideration by analysts. A test on a three-day data set was performed and showed that the system found 42 additional real events out of 116 examined, including 6 that pass the criterion for the Reviewed Event Bulletin of the IDC. The software was functional in a realistic, real-time mode, during the occurrence of the fourth nuclear test claimed by the Democratic People's Republic of Korea on January 6th, 2016. Confirming a previous statistical observation, the software found more associated stations (51, including 35 primary stations) than GA (36, including 26 primary stations) for this event. Nimar S. Arora, Stuart Russell, Erik Sudderth. Bulletin of the Seismological Society of America (BSSA) April 2013, vol. 103 no. 2A pp709-729.

  6. Predicting electromyographic signals under realistic conditions using a multiscale chemo–electro–mechanical finite element model

    PubMed Central

    Mordhorst, Mylena; Heidlauf, Thomas; Röhrle, Oliver

    2015-01-01

    This paper presents a novel multiscale finite element-based framework for modelling electromyographic (EMG) signals. The framework combines (i) a biophysical description of the excitation–contraction coupling at the half-sarcomere level, (ii) a model of the action potential (AP) propagation along muscle fibres, (iii) a continuum-mechanical formulation of force generation and deformation of the muscle, and (iv) a model for predicting the intramuscular and surface EMG. Owing to the biophysical description of the half-sarcomere, the model inherently accounts for physiological properties of skeletal muscle. To demonstrate this, the influence of membrane fatigue on the EMG signal during sustained contractions is investigated. During a stimulation period of 500 ms at 100 Hz, the predicted EMG amplitude decreases by 40% and the AP propagation velocity decreases by 15%. Further, the model can take into account contraction-induced deformations of the muscle. This is demonstrated by simulating fixed-length contractions of an idealized geometry and a model of the human tibialis anterior muscle (TA). The model of the TA furthermore demonstrates that the proposed finite element model is capable of simulating realistic geometries, complex fibre architectures, and can include different types of heterogeneities. In addition, the TA model accounts for a distributed innervation zone, different fibre types and appeals to motor unit discharge times that are based on a biophysical description of the α motor neurons. PMID:25844148

  7. Predicting field-scale dispersion under realistic conditions with the polar Markovian velocity process model

    NASA Astrophysics Data System (ADS)

    Dünser, Simon; Meyer, Daniel W.

    2016-06-01

    In most groundwater aquifers, dispersion of tracers is dominated by flow-field inhomogeneities resulting from the underlying heterogeneous conductivity or transmissivity field. This effect is referred to as macrodispersion. Since in practice, besides a few point measurements the complete conductivity field is virtually never available, a probabilistic treatment is needed. To quantify the uncertainty in tracer concentrations from a given geostatistical model for the conductivity, Monte Carlo (MC) simulation is typically used. To avoid the excessive computational costs of MC, the polar Markovian velocity process (PMVP) model was recently introduced delivering predictions at about three orders of magnitude smaller computing times. In artificial test cases, the PMVP model has provided good results in comparison with MC. In this study, we further validate the model in a more challenging and realistic setup. The setup considered is derived from the well-known benchmark macrodispersion experiment (MADE), which is highly heterogeneous and non-stationary with a large number of unevenly scattered conductivity measurements. Validations were done against reference MC and good overall agreement was found. Moreover, simulations of a simplified setup with a single measurement were conducted in order to reassess the model's most fundamental assumptions and to provide guidance for model improvements.

  8. Capture Conditions for Merging Trajectory Segments to Model Realistic Aircraft Descents

    NASA Technical Reports Server (NTRS)

    Zhao, Yiyuan; Slattery, Rhonda A.

    1996-01-01

    A typical commercial aircraft trajectory consists of a series of flight segments. An aircraft switches from one segment to another when certain specified variables reach their desired values. Trajectory synthesis for air traffic control automation must be consistent with practical pilot procedures. We examine capture conditions for merging trajectory segments to model commercial aircraft descent in trajectory synthesis. These conditions translate into bounds on measurements of atmospheric wind, pressure, and temperature. They also define ranges of thrust and drag feasible for a descent trajectory. Capture conditions are derived for the Center-TRACON Automation System developed at NASA Ames Research Center for automated air traffic control. Various uses of capture conditions are discussed. A Boeing 727-200 aircraft is used to provide numerical examples of capture conditions.

  9. Relevant influence of limestone crystallinity on CO₂ capture in the Ca-looping technology at realistic calcination conditions.

    PubMed

    Valverde, J M; Sanchez-Jimenez, P E; Perez-Maqueda, L A

    2014-08-19

    We analyze the role of limestone crystallinity on its CO2 capture performance when subjected to carbonation/calcination cycles at conditions mimicking the Ca-looping (CaL) technology for postcombustion CO2 capture. The behavior of raw and pretreated limestones (milled and thermally annealed) is investigated by means of thermogravimetric analysis (TGA) tests under realistic sorbent regeneration conditions, which necessarily involve high CO2 partial pressure in the calciner and quick heating rates. The pretreatments applied lead to contrasting effects on the solid crystal structure and, therefore, on its resistance to solid-state diffusion. Our results show that decarbonation at high CO2 partial pressure is notably promoted by decreasing solid crystallinity. CaO regeneration is fully achieved under high CO2 partial pressure at 900 °C in short residence times for the milled limestone whereas complete regeneration for raw limestone requires a minimum calcination temperature of about 950 °C. Such a reduction of the calcination temperature and the consequent mitigation of multicyclic capture capacity decay would serve to enhance the efficiency of the CaL technology. On the other hand, the results of our study suggest that the use of highly crystalline limestones would be detrimental since excessively high calcination temperatures should be required to attain full decarbonation at realistic conditions. PMID:25029532

  10. On the consequences of a realistic conditional covariance in MMM-calculations

    NASA Astrophysics Data System (ADS)

    Sorge, Stefan; Günter, Sibylle; Röpke, Gerd

    1999-02-01

    The model microfield method (MMM) may be used to include the effect of ion motion in line shape calculations. This kind of modelling of the time evolution of the microfield as a stochastic process, as is done in this method, yields a short time behaviour of the conditional covariance of the model microfield, which differs considerably from a conditional covariance calculated by considering the real motion of the plasma ions (microscopic conditional covariance). In this work purely ionic broadened hydrogen 0953-4075/32/3/011/img6 profiles are calculated using the microscopic conditional covariance within the MMM. It is shown that, depending on the reduced radiator-perturber mass, these MMM calculations may lead to unphysical line shapes. For comparison, hydrogen 0953-4075/32/3/011/img6 profiles derived within the MMM using the kangaroo process and from line shape simulations are given.

  11. Understanding the motivation and performance of community health volunteers involved in the delivery of health programmes in Kampala, Uganda: a realist evaluation protocol

    PubMed Central

    Vareilles, Gaëlle; Pommier, Jeanine; Kane, Sumit; Pictet, Gabriel; Marchal, Bruno

    2015-01-01

    Introduction The recruitment of community health volunteers to support the delivery of health programmes is a well-established approach in many countries, particularly where health services are not readily available. However, studies on management of volunteers are scarce and current research on human resource management of volunteers faces methodological challenges. This paper presents the protocol of a realist evaluation that aims at identifying the factors influencing the performance of community health volunteers involved in the delivery of a Red Cross immunisation programme in Kampala (Uganda) with a specific focus on motivation. Methods and analysis The realist evaluation cycle structures the protocol. To develop the theoretical basis for the evaluation, the authors conducted interviews and reviewed the literature on community health volunteers’ performance, management and organisational behaviour. This led to the formulation of the initial programme theory, which links the intervention inputs (capacity-building strategies) to the expected outcomes (positive work behaviour) with mechanisms that point in the direction of drivers of motivation. The contextual elements include components such as organisational culture, resource availability, etc. A case study design will be adopted. We define a case as a Red Cross branch, run by a programme manager, and will select two cases at the district level in Kampala. Mixed methods will be used in data collection, including individual interviews of volunteers, participant observation and document review. The thematic analysis will be based on the initial programme theory and will seek for context-mechanism-outcome configurations. Findings from the two cases will be compared. Discussion We discuss the scope for applying realist evaluation and the methodological challenges we encountered in developing this protocol. Ethics and dissemination The study was approved by the Ethical Committee at Rennes University Hospital

  12. The stability of solar coronal loops with realistic photospheric boundary conditions

    NASA Technical Reports Server (NTRS)

    Van Hoven, G.; Ma, S. S.; Einaudi, G.

    1981-01-01

    Finite-length effects are the primary influence for the MHD stability of coronal loops. This paper gives a new physical description of the photospheric boundary conditions, and the first complete and uniformly convergent initial-perturbation set. A general energy-principle (or variational) stability analysis is then developed. The results of this calculation show that large classes of cylindrical-symmetry perturbations, those with separable contributions to the energy integral, are completely stable. Comparisons are also made with other more restrictive formulations of this problem.

  13. Does therapeutic writing help people with long-term conditions? Systematic review, realist synthesis and economic considerations.

    PubMed Central

    Nyssen, Olga P; Taylor, Stephanie Jc; Wong, Geoff; Steed, Elizabeth; Bourke, Liam; Lord, Joanne; Ross, Carol A; Hayman, Sheila; Field, Victoria; Higgins, Ailish; Greenhalgh, Trisha; Meads, Catherine

    2016-01-01

    BACKGROUND Writing therapy to improve physical or mental health can take many forms. The most researched model of therapeutic writing (TW) is unfacilitated, individual expressive writing (written emotional disclosure). Facilitated writing activities are less widely researched. DATA SOURCES Databases, including MEDLINE, EMBASE, PsycINFO, Linguistics and Language Behaviour Abstracts, Allied and Complementary Medicine Database and Cumulative Index to Nursing and Allied Health Literature, were searched from inception to March 2013 (updated January 2015). REVIEW METHODS Four TW practitioners provided expert advice. Study procedures were conducted by one reviewer and checked by a second. Randomised controlled trials (RCTs) and non-randomised comparative studies were included. Quality was appraised using the Cochrane risk-of-bias tool. Unfacilitated and facilitated TW studies were analysed separately under International Classification of Diseases, Tenth Revision chapter headings. Meta-analyses were performed where possible using RevMan version 5.2.6 (RevMan 2012, The Cochrane Collaboration, The Nordic Cochrane Centre, Copenhagen, Denmark). Costs were estimated from a UK NHS perspective and three cost-consequence case studies were prepared. Realist synthesis followed Realist and Meta-narrative Evidence Synthesis: Evolving Standards guidelines. OBJECTIVES To review the clinical effectiveness and cost-effectiveness of TW for people with long-term conditions (LTCs) compared with no writing, or other controls, reporting any relevant clinical outcomes. To conduct a realist synthesis to understand how TW might work, and for whom. RESULTS From 14,658 unique citations, 284 full-text papers were reviewed and 64 studies (59 RCTs) were included in the final effectiveness reviews. Five studies examined facilitated TW; these were extremely heterogeneous with unclear or high risk of bias but suggested that facilitated TW interventions may be beneficial in individual LTCs. Unfacilitated

  14. Balancing student/trainee learning with the delivery of patient care in the healthcare workplace: a protocol for realist synthesis

    PubMed Central

    Sholl, Sarah; Ajjawi, Rola; Allbutt, Helen; Butler, Jane; Jindal-Snape, Divya; Morrison, Jill; Rees, Charlotte

    2016-01-01

    Introduction A national survey was recently conducted to explore medical education research priorities in Scotland. The identified themes and underlying priority areas can be linked to current medical education drivers in the UK. The top priority area rated by stakeholders was: ‘Understanding how to balance service and training conflicts’. Despite its perceived importance, a preliminary scoping exercise revealed the least activity with respect to published literature reviews. This protocol has therefore been developed so as to understand how patient care, other service demands and student/trainee learning can be simultaneously facilitated within the healthcare workplace. The review will identify key interventions designed to balance patient care and student/trainee learning, to understand how and why such interventions produce their effects. Our research questions seek to address how identified interventions enable balanced patient care-trainee learning within the healthcare workplace, for whom, why and under what circumstances. Methods and analysis Pawson's five stages for undertaking a realist review underpin this protocol. These stages may progress in a non-linear fashion due to the iterative nature of the review process. We will: (1) clarify the scope of the review, identifying relevant interventions and existing programme theories, understanding how interventions act to produce their intended outcomes; (2) search journal articles and grey literature for empirical evidence from 1998 (introduction of the European Working Time Directive) on the UK multidisciplinary team working concerning these interventions, theories and outcomes, using databases such as ERIC, Scopus and CINAHL; (3) assess study quality; (4) extract data; and (5) synthesise data, drawing conclusions. Ethics and dissemination A formal ethical review is not required. These findings should provide an important understanding of how workplace-based interventions influence the balance of trainee

  15. 43 CFR 418.28 - Conditions of delivery.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... deliveries. If water is delivered to ineligible land or in excess of the appropriate water duty then: (1) The... year to determine the amount of water required to enable the delivery of full entitlements at... District or individual water users....

  16. 43 CFR 418.28 - Conditions of delivery.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... deliveries. If water is delivered to ineligible land or in excess of the appropriate water duty then: (1) The... year to determine the amount of water required to enable the delivery of full entitlements at... District or individual water users....

  17. 43 CFR 418.28 - Conditions of delivery.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... deliveries. If water is delivered to ineligible land or in excess of the appropriate water duty then: (1) The... year to determine the amount of water required to enable the delivery of full entitlements at... District or individual water users....

  18. 43 CFR 418.28 - Conditions of delivery.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... deliveries. If water is delivered to ineligible land or in excess of the appropriate water duty then: (1) The... year to determine the amount of water required to enable the delivery of full entitlements at... District or individual water users....

  19. Improvement in Simulation of Eurasian Winter Climate Variability with a Realistic Arctic Sea Ice Condition in an Atmospheric GCM

    NASA Technical Reports Server (NTRS)

    Lim, Young-Kwon; Ham, Yoo-Geun; Jeong, Jee-Hoon; Kug, Jong-Seong

    2012-01-01

    The present study investigates how much a realistic Arctic sea ice condition can contribute to improve simulation of the winter climate variation over the Eurasia region. Model experiments are set up using different sea ice boundary conditions over the past 24 years (i.e., 1988-2011). One is an atmospheric model inter-comparison (AMIP) type of run forced with observed sea-surface temperature (SST), sea ice, and greenhouse gases (referred to as Exp RSI), and the other is the same as Exp RSI except for the sea ice forcing, which is a repeating climatological annual cycle (referred to as Exp CSI). Results show that Exp RSI produces the observed dominant pattern of Eurasian winter temperatures and their interannual variation better than Exp CSI (correlation difference up to approx. 0.3). Exp RSI captures the observed strong relationship between the sea ice concentration near the Barents and Kara seas and the temperature anomaly across Eurasia, including northeastern Asia, which is not well captured in Exp CSI. Lagged atmospheric responses to sea ice retreat are examined using observations to understand atmospheric processes for the Eurasian cooling response including the Arctic temperature increase, sea-level pressure increase, upper-level jet weakening and cold air outbreak toward the mid-latitude. The reproducibility of these lagged responses by Exp RSI is also evaluated.

  20. Experimental analysis of the vorticity and turbulent flow dynamics of a pitching airfoil at realistic flight (helicopter) conditions

    NASA Astrophysics Data System (ADS)

    Sahoo, Dipankar

    Improved basic understanding, predictability, and controllability of vortex-dominated and unsteady aerodynamic flows are important in enhancement of the performance of next generation helicopters. The primary objective of this research project was improved understanding of the fundamental vorticity and turbulent flow physics for a dynamically stalling airfoil at realistic helicopter flight conditions. An experimental program was performed on a large-scale (C = 0.45 m) dynamically pitching NACA 0012 wing operating in the Texas A&M University large-scale wind tunnel. High-resolution particle image velocimetry data were acquired on the first 10-15% of the wing. Six test cases were examined including the unsteady (k>0) and steady (k=0) conditions. The relevant mechanical, shear and turbulent time-scales were all of comparable magnitude, which indicated that the flow was in a state of mechanical non-equilibrium, and the expected flow separation and reattachment hystersis was observed. Analyses of the databases provided new insights into the leading-edge Reynolds stress structure and the turbulent transport processes. Both of which were previously uncharacterized. During the upstroke motion of the wing, a bubble structure formed in the leading-edge Reynolds shear stress. The size of the bubble increased with increasing angle-of-attack before being diffused into a shear layer at full separation. The turbulent transport analyses indicated that the axial stress production was positive, where the transverse production was negative. This implied that axial turbulent stresses were being produced from the axial component of the mean flow. A significant portion of the energy was transferred to the transverse stress through the pressure-strain redistribution, and then back to the transverse mean flow through the negative transverse production. An opposite trend was observed further downstream of this region.

  1. Toxicokinetics of perfluorooctane sulfonate in birds under environmentally realistic exposure conditions and development of a kinetic predictive model.

    PubMed

    Tarazona, J V; Rodríguez, C; Alonso, E; Sáez, M; González, F; San Andrés, M D; Jiménez, B; San Andrés, M I

    2015-01-22

    This article describes the toxicokinetics of perfluorooctane sulfonate (PFOS) in birds under low repeated dosing, equivalent to 0.085 μg/kg per day, representing environmentally realistic exposure conditions. The best fitting was provided by a simple pseudo monocompartmental first-order kinetics model, regulated by two rates, with a pseudo first-order dissipation half-life of 230 days, accounting for real elimination as well as binding of PFOS to non-exchangeable structures. The calculated assimilation efficiency was 0.66 with confidence intervals of 0.64 and 0.68. The model calculations confirmed that the measured maximum concentrations were still far from the steady state situation, which for this dose regime, was estimated at a value of about 65 μg PFOS/L serum achieved after a theoretical 210 weeks continuous exposure. The results confirm a very different kinetics than that observed in single-dose experiments confirming clear dose-related differences in apparent elimination rates in birds, as described for humans and monkeys; suggesting that a capacity-limited saturable process should also be considered in the kinetic behavior of PFOS in birds. Pseudo first-order kinetic models are highly convenient and frequently used for predicting bioaccumulation of chemicals in livestock and wildlife; the study suggests that previous bioaccumulation models using half-lives obtained at high doses are expected to underestimate the biomagnification potential of PFOS. The toxicokinetic parameters presented here can be used for higher-tier bioaccumulation estimations of PFOS in chickens and as surrogate values for modeling PFOS kinetics in wild bird species. PMID:25445721

  2. Development of a versatile experimental setup for the evaluation of the photocatalytic properties of construction materials under realistic outdoor conditions.

    PubMed

    Suárez, S; Portela, R; Hernández-Alonso, M D; Sánchez, B

    2014-10-01

    samples at the same time. The suitability of the system for the evaluation of the DeNO x properties of construction elements at realistic outdoor conditions was demonstrated. The designed experimental device can be used 24/7 for testing materials under real fluctuations of NO x concentration, temperature, UV irradiation, and relative humidity and the presence of other outdoor air pollutants such as VOCs, SO x , or NH3. The chamber-based design allows comparing a photocatalytic material with respect to a reference substrate without the photoactive phase, or even the comparison of several outdoor elements at the same time. PMID:24652575

  3. 50 CFR Table 3a to Part 680 - Crab Delivery Condition Codes

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Crab Delivery Condition Codes 3a Table 3a... ZONE OFF ALASKA Pt. 680, Table 3a Table 3a to Part 680—Crab Delivery Condition Codes Code Description 01 Whole crab, live. 79 Deadloss....

  4. 50 CFR Table 3a to Part 680 - Crab Delivery Condition Codes

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Crab Delivery Condition Codes 3a Table 3a... ZONE OFF ALASKA Pt. 680, Table 3a Table 3a to Part 680—Crab Delivery Condition Codes Code Description 01 Whole crab, live. 79 Deadloss....

  5. 50 CFR Table 3a to Part 680 - Crab Delivery Condition Codes

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 50 Wildlife and Fisheries 13 2014-10-01 2014-10-01 false Crab Delivery Condition Codes 3a Table 3a... ZONE OFF ALASKA Pt. 680, Table 3a Table 3a to Part 680—Crab Delivery Condition Codes Code Description 01 Whole crab, live. 79 Deadloss....

  6. 50 CFR Table 3a to Part 680 - Crab Delivery Condition Codes

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Crab Delivery Condition Codes 3a Table 3a... ZONE OFF ALASKA Pt. 680, Table 3a Table 3a to Part 680—Crab Delivery Condition Codes Code Description 01 Whole crab, live. 79 Deadloss....

  7. 7 CFR 27.47 - Tender or delivery of cotton; conditions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false Tender or delivery of cotton; conditions. 27.47... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Cotton Class Certificates § 27.47 Tender or delivery of cotton; conditions. Subject to the provisions of §§ 27.52 through...

  8. 7 CFR 27.47 - Tender or delivery of cotton; conditions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false Tender or delivery of cotton; conditions. 27.47... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Cotton Class Certificates § 27.47 Tender or delivery of cotton; conditions. Subject to the provisions of §§ 27.52 through...

  9. 7 CFR 27.47 - Tender or delivery of cotton; conditions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Tender or delivery of cotton; conditions. 27.47... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Cotton Class Certificates § 27.47 Tender or delivery of cotton; conditions. Subject to the provisions of §§ 27.52 through...

  10. 7 CFR 27.47 - Tender or delivery of cotton; conditions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false Tender or delivery of cotton; conditions. 27.47... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Cotton Class Certificates § 27.47 Tender or delivery of cotton; conditions. Subject to the provisions of §§ 27.52 through...

  11. 7 CFR 27.47 - Tender or delivery of cotton; conditions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Tender or delivery of cotton; conditions. 27.47... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Cotton Class Certificates § 27.47 Tender or delivery of cotton; conditions. Subject to the provisions of §§ 27.52 through...

  12. 50 CFR Table 3a to Part 680 - Crab Delivery Condition Codes

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Crab Delivery Condition Codes 3a Table 3a to Part 680 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND... ZONE OFF ALASKA Pt. 680, Table 3a Table 3a to Part 680—Crab Delivery Condition Codes Code...

  13. 43 CFR 418.28 - Conditions of delivery.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... efficiency. To the extent that the actual District efficiency determined for an irrigation season is greater... discretionary use in accordance with state law. (2) Less efficient—Debited or added to Lahontan storage as an... deliveries. If water is delivered to ineligible land or in excess of the appropriate water duty then: (1)...

  14. Optical filter highlighting spectral features part II: quantitative measurements of cosmetic foundation and assessment of their spatial distributions under realistic facial conditions.

    PubMed

    Nishino, Ken; Nakamura, Mutsuko; Matsumoto, Masayuki; Tanno, Osamu; Nakauchi, Shigeki

    2011-03-28

    We previously proposed a filter that could detect cosmetic foundations with high discrimination accuracy [Opt. Express 19, 6020 (2011)]. This study extends the filter's functionality to the quantification of the amount of foundation and applies the filter for the assessment of spatial distributions of foundation under realistic facial conditions. Human faces that are applied with quantitatively controlled amounts of cosmetic foundations were measured using the filter. A calibration curve between pixel values of the image and the amount of foundation was created. The optical filter was applied to visualize spatial foundation distributions under realistic facial conditions, which clearly indicated areas on the face where foundation remained even after cleansing. Results confirm that the proposed filter could visualize and nondestructively inspect the foundation distributions. PMID:21451627

  15. Assessment of tbe Performance of Ablative Insulators Under Realistic Solid Rocket Motor Operating Conditions (a Doctoral Dissertation)

    NASA Technical Reports Server (NTRS)

    Martin, Heath Thomas

    2013-01-01

    Ablative insulators are used in the interior surfaces of solid rocket motors to prevent the mechanical structure of the rocket from failing due to intense heating by the high-temperature solid-propellant combustion products. The complexity of the ablation process underscores the need for ablative material response data procured from a realistic solid rocket motor environment, where all of the potential contributions to material degradation are present and in their appropriate proportions. For this purpose, the present study examines ablative material behavior in a laboratory-scale solid rocket motor. The test apparatus includes a planar, two-dimensional flow channel in which flat ablative material samples are installed downstream of an aluminized solid propellant grain and imaged via real-time X-ray radiography. In this way, the in-situ transient thermal response of an ablator to all of the thermal, chemical, and mechanical erosion mechanisms present in a solid rocket environment can be observed and recorded. The ablative material is instrumented with multiple micro-thermocouples, so that in-depth temperature histories are known. Both total heat flux and thermal radiation flux gauges have been designed, fabricated, and tested to characterize the thermal environment to which the ablative material samples are exposed. These tests not only allow different ablative materials to be compared in a realistic solid rocket motor environment but also improve the understanding of the mechanisms that influence the erosion behavior of a given ablative material.

  16. An automated dynamic chamber system for the laboratory simulation of soil biogenic nitric oxide emissions under realistic ambient conditions

    NASA Astrophysics Data System (ADS)

    Yang, W. X.; Trebs, I.; Ashuri, F.; Meixner, F. X.; van Dijk, S.; Lehmann, L.; Welling, M.

    2003-04-01

    The effects of (a) realistic ambient nitric oxide (NO) mixing ratios, (b) soil moisture, (c) soil temperature, and (c) soil nutrient availability on the emission and uptake of NO from and to soils respectively can be simulated by our laboratory dynamic chamber system. Four measurement chambers with soil samples as well as one reference (control) chamber made of polyacrylic glass are flushed continuously with air at a rate of 2.5 l min-1. The chambers are placed in a thermostat cabinet to control the soil temperature (0--30^oC). Inverted gas drying tubes are introduced into the system to maintain soil moisture at prescribed, but constant levels (0% to field capacity). A gas dilution system provides various NO mixing ratios (0--200 ppb). With this set-up we investigated production and consumption processes, as well as compensation mixing ratios of NO in soil samples as functions of soil moisture and temperature, soil nutrient concentrations, and ambient NO mixing ratio. NO emission /uptake fluxes are calculated from soil production and consumption rates with the help of the Galbally &Johansson algorithm (Galbally &Johansson, 1989). We will present a detailed description of the system, examples of derived results, as well as validation of the up-scaling procedures of chamber results to the field-size levels (South African, Brazilian, and Mid European ecosystems).

  17. System-state and operating condition sensitive control method and apparatus for electric power delivery systems

    NASA Technical Reports Server (NTRS)

    Burns, III, William Wesley (Inventor); Wilson, Thomas George (Inventor)

    1978-01-01

    This invention provides a method and apparatus for determining a precise switching sequence for the power switching elements of electric power delivery systems of the on-off switching type and which enables extremely fast transient response, precise regulation and highly stable operation. The control utilizes the values of the power delivery system power handling network components, a desired output characteristic, a system timing parameter, and the externally imposed operating conditions to determine where steady state operations should be in order to yield desired output characteristics for the given system specifications. The actual state of the power delivery system is continuously monitored and compared to a state-space boundary which is derived from the desired equilibrium condition, and from the information obtained from this comparison, the system is moved to the desired equilibrium condition in one cycle of switching control. Since the controller continuously monitors the power delivery system's externally imposed operating conditions, a change in the conditions is immediately sensed and a new equilibrium condition is determined and achieved, again in a single cycle of switching control.

  18. 50 CFR Table 1a to Part 679 - Delivery Condition* and Product Codes

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 50 Wildlife and Fisheries 13 2012-10-01 2012-10-01 false Delivery Condition* and Product Codes 1a Table 1a to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE...

  19. 50 CFR Table 1a to Part 679 - Delivery Condition* and Product Codes

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 11 2011-10-01 2011-10-01 false Delivery Condition* and Product Codes 1a Table 1a to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE...

  20. 50 CFR Table 1a to Part 679 - Delivery Condition* and Product Codes

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 50 Wildlife and Fisheries 13 2013-10-01 2013-10-01 false Delivery Condition* and Product Codes 1a Table 1a to Part 679 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE (CONTINUED) FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 679, Table 1a Table 1a...

  1. 7 CFR 735.110 - Conditions for delivery of agricultural products.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... product stored or handled in the warehouse on a demand made by: (1) The holder of the warehouse receipt... 7 Agriculture 7 2013-01-01 2013-01-01 false Conditions for delivery of agricultural products. 735.110 Section 735.110 Agriculture Regulations of the Department of Agriculture (Continued) FARM...

  2. 7 CFR 735.110 - Conditions for delivery of agricultural products.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... product stored or handled in the warehouse on a demand made by: (1) The holder of the warehouse receipt... 7 Agriculture 7 2012-01-01 2012-01-01 false Conditions for delivery of agricultural products. 735.110 Section 735.110 Agriculture Regulations of the Department of Agriculture (Continued) FARM...

  3. 7 CFR 735.110 - Conditions for delivery of agricultural products.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... product stored or handled in the warehouse on a demand made by: (1) The holder of the warehouse receipt... 7 Agriculture 7 2014-01-01 2014-01-01 false Conditions for delivery of agricultural products. 735.110 Section 735.110 Agriculture Regulations of the Department of Agriculture (Continued) FARM...

  4. 7 CFR 735.110 - Conditions for delivery of agricultural products.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... product stored or handled in the warehouse on a demand made by: (1) The holder of the warehouse receipt... 7 Agriculture 7 2011-01-01 2011-01-01 false Conditions for delivery of agricultural products. 735.110 Section 735.110 Agriculture Regulations of the Department of Agriculture (Continued) FARM...

  5. 7 CFR 735.110 - Conditions for delivery of agricultural products.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AGENCY, DEPARTMENT OF AGRICULTURE REGULATIONS FOR WAREHOUSES REGULATIONS FOR THE UNITED STATES WAREHOUSE ACT Warehouse Licensing § 735.110 Conditions for delivery of agricultural products. (a) In the absence of a lawful excuse, a warehouse operator will, without unnecessary delay, deliver the...

  6. Toxicokinetics of perfluorooctane sulfonate in rabbits under environmentally realistic exposure conditions and comparative assessment between mammals and birds.

    PubMed

    Tarazona, J V; Rodríguez, C; Alonso, E; Sáez, M; González, F; San Andrés, M D; Jiménez, B; San Andrés, M I

    2016-01-22

    This article describes the toxicokinetics of perfluorooctane sulfonate (PFOS) in rabbits under low repeated dosing, equivalent to 0.085μg/kg per day, and the observed differences between rabbits and chickens. The best fitting for both species was provided by a simple pseudo monocompartmental first-order kinetics model, regulated by two rates, and accounting for real elimination as well as binding of PFOS to non-exchangeable structures. Elimination was more rapid in rabbits, with a pseudo first-order dissipation half-life of 88 days compared to the 230 days observed for chickens. By contrast, the calculated assimilation efficiency for rabbits was almost 1, very close to full absorption, significantly higher than the 0.66 with confidence intervals of 0.64 and 0.68 observed for chickens. The results confirm a very different kinetics than that observed in single-dose experiments confirming clear dose-related differences in apparent elimination rates in rabbits, as previously described for humans and other mammals; suggesting the role of a capacity-limited saturable process resulting in different kinetic behaviours for PFOS in high dose versus environmentally relevant low dose exposure conditions. The model calculations confirmed that the measured maximum concentrations were still far from the steady state situation, and that the different kinetics between birds and mammals should may play a significant role in the biomagnifications assessment and potential exposure for humans and predators. For the same dose regime, the steady state concentration was estimated at about 36μg PFOS/L serum for rabbits, slightly above one-half of the 65μg PFOS/L serum estimated for chickens. The toxicokinetic parameters presented here can be used for higher-tier bioaccumulation estimations of PFOS in rabbits and chickens as starting point for human health exposure assessments and as surrogate values for modeling PFOS kinetics in wild mammals and bird in exposure assessment of predatory

  7. Multi-Physics Feedback Simulations with Realistic Initial Conditions of the Formation of Star Clusters: From Large Scale Magnetized Clouds to Turbulent Clumps to Cores to Stars

    NASA Astrophysics Data System (ADS)

    Klein, R. I.; Li, P.; McKee, C. F.

    2015-10-01

    Multi-physics zoom-in adaptive mesh refinement simulations with feedback and realistic initial conditions, starting from large scale turbulent molecular clouds through the formation of clumps and cores to the formation os stellar clusters are presented. I give a summary of results at the different scales undergoing gravitational collapse from cloud to core to cluster formation. Detailed comparisons with observations are made at each stage of the simulations. In particular, properties of the magnetized clumps are compared with recent observations of Crutcher et al. 2010 and Crutcher 2012 and the magnetic field orientation in cloud clumps relative to the global mean field of the inter-cloud medium (Li et al. 2009). The Initial Mass Function (IMF) obtained is compared with the Chabrier IMF and the protostellar mass function of the cluster is compared with different theories.

  8. Holdup measurements under realistic conditions

    SciTech Connect

    Sprinkel, J.K. Jr.; Marshall, R.; Russo, P.A.; Siebelist, R.

    1997-11-01

    This paper reviews the documentation of the precision and bias of holdup (residual nuclear material remaining in processing equipment) measurements and presents previously unreported results. Precision and bias results for holdup measurements are reported from training seminars with simulated holdup, which represent the best possible results, and compared to actual plutonium processing facility measurements. Holdup measurements for plutonium and uranium processing plants are also compared to reference values. Recommendations for measuring holdup are provided for highly enriched uranium facilities and for low enriched uranium facilities. The random error component of holdup measurements is less than the systematic error component. The most likely factor in measurement error is incorrect assumptions about the measurement, such as background, measurement geometry, or signal attenuation. Measurement precision on the order of 10% can be achieved with some difficulty. Bias of poor quality holdup measurement can also be improved. However, for most facilities, holdup measurement errors have no significant impact on inventory difference, sigma, or safety (criticality, radiation, or environmental); therefore, it is difficult to justify the allocation of more resources to improving holdup measurements. 25 refs., 10 tabs.

  9. Influence of a compost layer on the attenuation of 28 selected organic micropollutants under realistic soil aquifer treatment conditions: insights from a large scale column experiment.

    PubMed

    Schaffer, Mario; Kröger, Kerrin Franziska; Nödler, Karsten; Ayora, Carlos; Carrera, Jesús; Hernández, Marta; Licha, Tobias

    2015-05-01

    Soil aquifer treatment is widely applied to improve the quality of treated wastewater in its reuse as alternative source of water. To gain a deeper understanding of the fate of thereby introduced organic micropollutants, the attenuation of 28 compounds was investigated in column experiments using two large scale column systems in duplicate. The influence of increasing proportions of solid organic matter (0.04% vs. 0.17%) and decreasing redox potentials (denitrification vs. iron reduction) was studied by introducing a layer of compost. Secondary effluent from a wastewater treatment plant was used as water matrix for simulating soil aquifer treatment. For neutral and anionic compounds, sorption generally increases with the compound hydrophobicity and the solid organic matter in the column system. Organic cations showed the highest attenuation. Among them, breakthroughs were only registered for the cationic beta-blockers atenolol and metoprolol. An enhanced degradation in the columns with organic infiltration layer was observed for the majority of the compounds, suggesting an improved degradation for higher levels of biodegradable dissolved organic carbon. Solely the degradation of sulfamethoxazole could clearly be attributed to redox effects (when reaching iron reducing conditions). The study provides valuable insights into the attenuation potential for a wide spectrum of organic micropollutants under realistic soil aquifer treatment conditions. Furthermore, the introduction of the compost layer generally showed positive effects on the removal of compounds preferentially degraded under reducing conditions and also increases the residence times in the soil aquifer treatment system via sorption. PMID:25723339

  10. Designing field-controllable graphene-dot-graphene single molecule switches: A quantum-theoretical proof-of-concept under realistic operating conditions

    NASA Astrophysics Data System (ADS)

    Pejov, Ljupčo; Petreska, Irina; Kocarev, Ljupčo

    2015-12-01

    A theoretical proof of the concept that a particularly designed graphene-based moletronics device, constituted by two semi-infinite graphene subunits, acting as source and drain electrodes, and a central benzenoid ring rotator (a "quantum dot"), could act as a field-controllable molecular switch is outlined and analyzed with the density functional theory approach. Besides the ideal (0 K) case, we also consider the operation of such a device under realistic operating (i.e., finite-temperature) conditions. An in-depth insight into the physics behind device controllability by an external field was gained by thorough analyses of the torsional potential of the dot under various conditions (absence or presence of an external gating field with varying strength), computing the torsional correlation time and transition probabilities within the Bloembergen-Purcell-Pound formalism. Both classical and quantum mechanical tunneling contributions to the intramolecular rotation were considered in the model. The main idea that we put forward in the present study is that intramolecular rotors can be controlled by the gating field even in cases when these groups do not possess a permanent dipole moment (as in cases considered previously by us [I. Petreska et al., J. Chem. Phys. 134, 014708-1-014708-12 (2011)] and also by other groups [P. E. Kornilovitch et al., Phys. Rev. B 66, 245413-1-245413-7 (2002)]). Consequently, one can control the molecular switching properties by an external electrostatic field utilizing even nonpolar intramolecular rotors (i.e., in a more general case than those considered so far). Molecular admittance of the currently considered graphene-based molecular switch under various conditions is analyzed employing non-equilibrium Green's function formalism, as well as by analysis of frontier molecular orbitals' behavior.

  11. Designing field-controllable graphene-dot-graphene single molecule switches: A quantum-theoretical proof-of-concept under realistic operating conditions.

    PubMed

    Pejov, Ljupčo; Petreska, Irina; Kocarev, Ljupčo

    2015-12-28

    A theoretical proof of the concept that a particularly designed graphene-based moletronics device, constituted by two semi-infinite graphene subunits, acting as source and drain electrodes, and a central benzenoid ring rotator (a "quantum dot"), could act as a field-controllable molecular switch is outlined and analyzed with the density functional theory approach. Besides the ideal (0 K) case, we also consider the operation of such a device under realistic operating (i.e., finite-temperature) conditions. An in-depth insight into the physics behind device controllability by an external field was gained by thorough analyses of the torsional potential of the dot under various conditions (absence or presence of an external gating field with varying strength), computing the torsional correlation time and transition probabilities within the Bloembergen-Purcell-Pound formalism. Both classical and quantum mechanical tunneling contributions to the intramolecular rotation were considered in the model. The main idea that we put forward in the present study is that intramolecular rotors can be controlled by the gating field even in cases when these groups do not possess a permanent dipole moment (as in cases considered previously by us [I. Petreska et al., J. Chem. Phys. 134, 014708-1-014708-12 (2011)] and also by other groups [P. E. Kornilovitch et al., Phys. Rev. B 66, 245413-1-245413-7 (2002)]). Consequently, one can control the molecular switching properties by an external electrostatic field utilizing even nonpolar intramolecular rotors (i.e., in a more general case than those considered so far). Molecular admittance of the currently considered graphene-based molecular switch under various conditions is analyzed employing non-equilibrium Green's function formalism, as well as by analysis of frontier molecular orbitals' behavior. PMID:26723699

  12. Designing field-controllable graphene-dot-graphene single molecule switches: A quantum-theoretical proof-of-concept under realistic operating conditions

    SciTech Connect

    Pejov, Ljupčo; Petreska, Irina; Kocarev, Ljupčo

    2015-12-28

    A theoretical proof of the concept that a particularly designed graphene-based moletronics device, constituted by two semi-infinite graphene subunits, acting as source and drain electrodes, and a central benzenoid ring rotator (a “quantum dot”), could act as a field-controllable molecular switch is outlined and analyzed with the density functional theory approach. Besides the ideal (0 K) case, we also consider the operation of such a device under realistic operating (i.e., finite-temperature) conditions. An in-depth insight into the physics behind device controllability by an external field was gained by thorough analyses of the torsional potential of the dot under various conditions (absence or presence of an external gating field with varying strength), computing the torsional correlation time and transition probabilities within the Bloembergen-Purcell-Pound formalism. Both classical and quantum mechanical tunneling contributions to the intramolecular rotation were considered in the model. The main idea that we put forward in the present study is that intramolecular rotors can be controlled by the gating field even in cases when these groups do not possess a permanent dipole moment (as in cases considered previously by us [I. Petreska et al., J. Chem. Phys. 134, 014708-1–014708-12 (2011)] and also by other groups [P. E. Kornilovitch et al., Phys. Rev. B 66, 245413-1–245413-7 (2002)]). Consequently, one can control the molecular switching properties by an external electrostatic field utilizing even nonpolar intramolecular rotors (i.e., in a more general case than those considered so far). Molecular admittance of the currently considered graphene-based molecular switch under various conditions is analyzed employing non-equilibrium Green’s function formalism, as well as by analysis of frontier molecular orbitals’ behavior.

  13. Ce K edge XAS of ceria-based redox materials under realistic conditions for the two-step solar thermochemical dissociation of water and/or CO2.

    PubMed

    Rothensteiner, Matthäus; Sala, Simone; Bonk, Alexander; Vogt, Ulrich; Emerich, Hermann; van Bokhoven, Jeroen A

    2015-10-28

    X-ray absorption spectroscopy was used to characterise ceria-based materials under realistic conditions present in a reactor for solar thermochemical two-step water and carbon dioxide splitting. A setup suitable for in situ measurements in transmission mode at the cerium K edge from room temperature up to 1773 K is presented. Time-resolved X-ray absorption near-edge structure (XANES) data, collected for a 10 mol% hafnium-doped ceria sample (Ce0.9Hf0.1O2-δ) during reduction at 1773 K in a flow of inert gas and during re-oxidation by CO2 at 1073 K, enables the quantitative determination of the non-stoichiometry δ of the fluorite-type structure. XANES analysis suggests the formation of the hexagonal Ce2O3 phase upon reduction in 2% hydrogen/helium at 1773 K. We discuss the experimental limitations and possibilities of high-temperature in situ XAS at edges of lower energy as well as the importance of the technique for understanding and improving the properties of ceria-based oxygen storage materials for thermochemical solar energy conversion. PMID:26412705

  14. Sintering and reactivity of CaCO{sub 3}-based sorbents for in situ CO{sub 2} capture in fluidized beds under realistic calcination conditions

    SciTech Connect

    Lu, D.Y.; Hughes, R.W.; Anthony, E.J.; Manovic, V.

    2009-06-15

    Sintering during calcination/carbonation may introduce substantial economic penalties for a CO{sub 2} looping cycle using limestone/dolomite-derived sorbents. Cyclic carbonation and calcination reactions were investigated for CO{sub 2} capture under fluidized bed combustion (FBC) conditions. The cyclic carbonation characteristics of CaCO{sub 3}-derived sorbents were compared at various calcination temperatures (700-925{sup o} C) and different gas stream compositions: pure -2 and a realistic calciner environment where high concentrations of CO{sub 2}>80-90% are expected. The conditions during carbonation were 700 {sup o}C and 15% CO{sub 2} in N{sub 2} and 0.18% or 0.50% SO{sub 2} in selected tests. Up to 20 calcination/carbonation cycles were conducted using a thermogravimetric analyzer (TGA) apparatus. Three Canadian limestones were tested: Kelly Rock, Havelock, and Cadomin, using a prescreened particle size range of 400-650 {mu} m. Calcined Kelly Rock and Cadomin samples were hydrated by steam and examined. Sorbent reactivity was reduced whenever SO{sub 2} was introduced to either the calcining or carbonation streams. The multicyclic capture capacity of CaO for CO{sub 2} was substantially reduced at high concentrations of CO{sub 2} during the sorbent regeneration process and carbonation conversion of the Kelly Rock sample obtained after 20 cycles was only 10.5%. Hydrated sorbents performed better for CO{sub 2} capture but showed deterioration following calcination in high CO{sub 2} gas streams indicating that high CO{sub 2} and SO{sub 2} levels in the gas stream lead to lower CaO conversion because of enhanced sintering and irreversible formation of CaSO{sub 4}.

  15. Delivery

    PubMed Central

    Miller, Thomas A

    2013-01-01

    Enthusiasm greeted the development of synthetic organic insecticides in the mid-twentieth century, only to see this give way to dismay and eventually scepticism and outright opposition by some. Regardless of how anyone feels about this issue, insecticides and other pesticides have become indispensable, which creates something of a dilemma. Possibly as a result of the shift in public attitude towards insecticides, genetic engineering of microbes was first met with scepticism and caution among scientists. Later, the development of genetically modified crop plants was met with an attitude that hardened into both acceptance and hard-core resistance. Transgenic insects, which came along at the dawn of the twenty-first century, encountered an entrenched opposition. Those of us responsible for studying the protection of crops have been affected more or less by these protagonist and antagonistic positions, and the experiences have often left one thoughtfully mystified as decisions are made by non-participants. Most of the issues boil down to concerns over delivery mechanisms. © 2013 Society of Chemical Industry PMID:23852646

  16. Particulate Matter from Both Heavy Fuel Oil and Diesel Fuel Shipping Emissions Show Strong Biological Effects on Human Lung Cells at Realistic and Comparable In Vitro Exposure Conditions

    PubMed Central

    Dilger, Marco; Paur, Hanns-Rudolf; Schlager, Christoph; Mülhopt, Sonja; Diabaté, Silvia; Weiss, Carsten; Stengel, Benjamin; Rabe, Rom; Harndorf, Horst; Torvela, Tiina; Jokiniemi, Jorma K.; Hirvonen, Maija-Riitta; Schmidt-Weber, Carsten; Traidl-Hoffmann, Claudia; BéruBé, Kelly A.; Wlodarczyk, Anna J.; Prytherch, Zoë; Michalke, Bernhard; Krebs, Tobias; Prévôt, André S. H.; Kelbg, Michael; Tiggesbäumker, Josef; Karg, Erwin; Jakobi, Gert; Scholtes, Sorana; Schnelle-Kreis, Jürgen; Lintelmann, Jutta; Matuschek, Georg; Sklorz, Martin; Klingbeil, Sophie; Orasche, Jürgen; Richthammer, Patrick; Müller, Laarnie; Elsasser, Michael; Reda, Ahmed; Gröger, Thomas; Weggler, Benedikt; Schwemer, Theo; Czech, Hendryk; Rüger, Christopher P.; Abbaszade, Gülcin; Radischat, Christian; Hiller, Karsten; Buters, Jeroen T. M.; Dittmar, Gunnar; Zimmermann, Ralf

    2015-01-01

    Background Ship engine emissions are important with regard to lung and cardiovascular diseases especially in coastal regions worldwide. Known cellular responses to combustion particles include oxidative stress and inflammatory signalling. Objectives To provide a molecular link between the chemical and physical characteristics of ship emission particles and the cellular responses they elicit and to identify potentially harmful fractions in shipping emission aerosols. Methods Through an air-liquid interface exposure system, we exposed human lung cells under realistic in vitro conditions to exhaust fumes from a ship engine running on either common heavy fuel oil (HFO) or cleaner-burning diesel fuel (DF). Advanced chemical analyses of the exhaust aerosols were combined with transcriptional, proteomic and metabolomic profiling including isotope labelling methods to characterise the lung cell responses. Results The HFO emissions contained high concentrations of toxic compounds such as metals and polycyclic aromatic hydrocarbon, and were higher in particle mass. These compounds were lower in DF emissions, which in turn had higher concentrations of elemental carbon (“soot”). Common cellular reactions included cellular stress responses and endocytosis. Reactions to HFO emissions were dominated by oxidative stress and inflammatory responses, whereas DF emissions induced generally a broader biological response than HFO emissions and affected essential cellular pathways such as energy metabolism, protein synthesis, and chromatin modification. Conclusions Despite a lower content of known toxic compounds, combustion particles from the clean shipping fuel DF influenced several essential pathways of lung cell metabolism more strongly than particles from the unrefined fuel HFO. This might be attributable to a higher soot content in DF. Thus the role of diesel soot, which is a known carcinogen in acute air pollution-induced health effects should be further investigated. For the

  17. Disparity profiles in 3DV applications: overcoming the issue of heterogeneous viewing conditions in stereoscopic delivery

    NASA Astrophysics Data System (ADS)

    Boisson, Guillaume; Chamaret, Christel

    2012-03-01

    More and more numerous 3D movies are released each year. Thanks to the current spread of 3D-TV displays, these 3D Video (3DV) contents are about to enter massively the homes. Yet viewing conditions determine the stereoscopic features achievable for 3DV material. Because the conditions at home - screen size and distance to screen - differ significantly from a theater, 3D Cinema movies need to be repurposed before broadcast and replication on 3D Blu-ray Discs for being fully enjoyed at home. In that paper we tackle that particular issue of how to handle the variety of viewing conditions in stereoscopic contents delivery. To that extend we first investigate what is basically at stake for granting stereoscopic viewers' comfort, through the well-known - and sometimes dispraised - vergence-accommodation conflict. Thereby we define a set of basic rules that can serve as guidelines for 3DV creation. We propose disparity profiles as new requirements for 3DV production and repurposing. Meeting proposed background and foreground constraints prevents from visual fatigue, and occupying the whole depth budget available grants optimal 3D effects. We present an efficient algorithm for automatic disparity-based 3DV retargeting depending on the viewing conditions. Variants are proposed depending on the input format (stereoscopic binocular content or depth-based format) and the level of complexity achievable.

  18. Effect of delivery condition on desorption rate of ZrCo metal hydride bed for fusion fuel cycle

    SciTech Connect

    Kang, H.G.; Yun, S.H.; Chung, D.; Oh, Y.H.; Chang, M.H.; Cho, S.; Chung, H.; Song, K.M.

    2015-03-15

    For the safety of fusion fuel cycle, hydrogen isotope gases including tritium are stored as metal hydride form. To satisfy fueling requirement of fusion machine, rapid delivery from metal hydride bed is one of major factors for the development of tritium storage and delivery system. Desorption from metal hydride depends on the operation scenario by pressure and temperature control of the bed. The effect of operation scenario and pump performance on desorption rate of metal hydride bed was experimentally investigated using ZrCo bed. The results showed that the condition of pre-heating scenario before actual delivery of gas affected the delivery performance. Different pumps were connected to desorption line from bed and the effect of pump capacity on desorption rate were also found to be significant. (authors)

  19. Highly stable and degradable multifunctional microgel for self-regulated insulin delivery under physiological conditions

    NASA Astrophysics Data System (ADS)

    Zhang, Xinjie; Lü, Shaoyu; Gao, Chunmei; Chen, Chen; Zhang, Xuan; Liu, Mingzhu

    2013-06-01

    The response to glucose, pH and temperature, high drug loading capacity, self-regulated drug delivery and degradation in vivo are simultaneously probable by applying a multifunctional microgel under a rational design in a colloid chemistry method. Such multifunctional microgels are fabricated with N-isopropylacrylamide (NIPAAm), (2-dimethylamino)ethyl methacrylate (DMAEMA) and 3-acrylamidephenylboronic acid (AAPBA) through a precipitation emulsion method and cross-linked by reductive degradable N,N'-bis(arcyloyl)cystamine (BAC). This novel kind of microgel with a narrow size distribution (~250 nm) is suitable for diabetes because it can adapt to the surrounding medium of different glucose concentrations over a clinically relevant range (0-20 mM), control the release of preloaded insulin and is highly stable under physiological conditions (pH 7.4, 0.15 M NaCl, 37 °C). When synthesized multifunctional microgels regulate drug delivery, they gradually degrade as time passes and, as a result, show enhanced biocompatibility. This exhibits a new proof-of-concept for diabetes treatment that takes advantage of the properties of each building block from a multifunctional micro-object. These highly stable and versatile multifunctional microgels have the potential to be used for self-regulated therapy and monitoring of the response to treatment, or even simultaneous diagnosis as nanobiosensors.The response to glucose, pH and temperature, high drug loading capacity, self-regulated drug delivery and degradation in vivo are simultaneously probable by applying a multifunctional microgel under a rational design in a colloid chemistry method. Such multifunctional microgels are fabricated with N-isopropylacrylamide (NIPAAm), (2-dimethylamino)ethyl methacrylate (DMAEMA) and 3-acrylamidephenylboronic acid (AAPBA) through a precipitation emulsion method and cross-linked by reductive degradable N,N'-bis(arcyloyl)cystamine (BAC). This novel kind of microgel with a narrow size

  20. Performance of an ARC-enabled computing grid for ATLAS/LHC physics analysis and Monte Carlo production under realistic conditions

    NASA Astrophysics Data System (ADS)

    Samset, B. H.; Cameron, D.; Ellert, M.; Filipcic, A.; Gronager, M.; Kleist, J.; Maffioletti, S.; Ould-Saada, F.; Pajchel, K.; Read, A. L.; Taga, A.; ATLAS Collaboration

    2010-04-01

    A significant amount of the computing resources available to the ATLAS experiment at the LHC are connected via the ARC grid middleware. ATLAS ARC-enabled resources, which consist of both major computing centers at the Tier-1 level and lesser, local clusters at Tier-2 and 3 level, have shown excellent performance running heavy Monte Carlo (MC) production for the experiment. However, with the imminent arrival of LHC physics data, it is imperative that the deployed grid middlewares also can handle data access patterns caused by user-defined physics analysis. These user-defined jobs can have radically different demands than systematic, centrally controlled MC production. We report on the performance of the ARC middleware, as deployed for ATLAS, for realistic situations with concurrent MC production and physics analysis running on the same resources. Data access patterns for ATLAS MC and physics analysis grid jobs will be shown, together with the performance of various possible storage and file staging models.

  1. Realistic collective nuclear Hamiltonian

    SciTech Connect

    Dufour, M.; Zuker, A.P.

    1996-10-01

    The residual part of the realistic forces{emdash}obtained after extracting the monopole terms responsible for bulk properties{emdash}is strongly dominated by pairing and quadrupole interactions, with important {sigma}{tau}{center_dot}{sigma}{tau}, octupole, and hexadecapole contributions. Their forms retain the simplicity of the traditional pairing plus multipole models, while eliminating their flaws through a normalization mechanism dictated by a universal {ital A}{sup {minus}1/3} scaling. Coupling strengths and effective charges are calculated and shown to agree with empirical values. Comparisons between different realistic interactions confirm the claim that they are very similar. {copyright} {ital 1996 The American Physical Society.}

  2. Realistic and Schematic Visuals.

    ERIC Educational Resources Information Center

    Heuvelman, Ard

    1996-01-01

    A study examined three different visual formats (studio presenter only, realistic visuals, or schematic visuals) of an educational television program. Recognition and recall of the abstract subject matter were measured in 101 adult viewers directly after the program and 3 months later. The schematic version yielded better recall of the program,…

  3. The Educational Value of Visual Cues and 3D-Representational Format in a Computer Animation under Restricted and Realistic Conditions

    ERIC Educational Resources Information Center

    Huk, Thomas; Steinke, Mattias; Floto, Christian

    2010-01-01

    Within the framework of cognitive learning theories, instructional design manipulations have primarily been investigated under tightly controlled laboratory conditions. We carried out two experiments, where the first experiment was conducted in a restricted system-paced setting and is therefore in line with the majority of empirical studies in the…

  4. Simulation of realistic retinoscopic measurement

    NASA Astrophysics Data System (ADS)

    Tan, Bo; Chen, Ying-Ling; Baker, K.; Lewis, J. W.; Swartz, T.; Jiang, Y.; Wang, M.

    2007-03-01

    Realistic simulation of ophthalmic measurements on normal and diseased eyes is presented. We use clinical data of ametropic and keratoconus patients to construct anatomically accurate three-dimensional eye models and simulate the measurement of a streak retinoscope with all the optical elements. The results show the clinical observations including the anomalous motion in high myopia and the scissors reflex in keratoconus. The demonstrated technique can be applied to other ophthalmic instruments and to other and more extensively abnormal eye conditions. It provides promising features for medical training and for evaluating and developing ocular instruments.

  5. Implantation of Miniosmotic Pumps and Delivery of Tract Tracers to Study Brain Reorganization in Pathophysiological Conditions.

    PubMed

    Sanchez-Mendoza, Eduardo H; Carballo, Jeismar; Longart, Marines; Hermann, Dirk M; Doeppner, Thorsten R

    2016-01-01

    Pharmacological treatment in animal models of cerebral disease imposes the problem of repeated injection protocols that may induce stress in animals and result in impermanent tissue levels of the drug. Additionally, drug delivery to the brain is delicate due to the blood brain barrier (BBB), thus significantly reducing intracerebral concentrations of selective drugs after systemic administration. Therefore, a system that allows both constant drug delivery without peak levels and circumvention of the BBB is in order to achieve sufficiently high intracerebral concentrations of drugs that are impermeable to the BBB. In this context, miniosmotic pumps represent an ideal system for constant drug delivery at a fixed known rate that eludes the problem of daily injection stress in animals and that may also be used for direct brain delivery of drugs. Here, we describe a method for miniosmotic pump implantation and post operatory care that should be given to animals in order to successfully apply this technique. We embed the aforementioned experimental paradigm in standard procedures that are used for studying neuroplasticity within the brain of C57BL6 mice. Thus, we exposed animals to 30 min brain infarct and implanted with miniosmotic pumps connected to the skull via a cannula in order to deliver a pro-plasticity drug. Behavioral testing was done during 30 days of treatment. After removal the animals received injections of anterograde tract tracers to analyze neuronal plasticity in the chronic phase of recovery. Results indicated that neuroprotection by the delivered drug was accompanied with increase in motor fibers crossing the midline of the brain at target structures. The results affirm the value of these techniques for drug administration and brain plasticity studies in modern neuroscience. PMID:26863287

  6. Implantation of Miniosmotic Pumps and Delivery of Tract Tracers to Study Brain Reorganization in Pathophysiological Conditions

    PubMed Central

    Sanchez-Mendoza, Eduardo H.; Carballo, Jeismar; Longart, Marines; Hermann, Dirk M.; Doeppner, Thorsten R.

    2016-01-01

    Pharmacological treatment in animal models of cerebral disease imposes the problem of repeated injection protocols that may induce stress in animals and result in impermanent tissue levels of the drug. Additionally, drug delivery to the brain is delicate due to the blood brain barrier (BBB), thus significantly reducing intracerebral concentrations of selective drugs after systemic administration. Therefore, a system that allows both constant drug delivery without peak levels and circumvention of the BBB is in order to achieve sufficiently high intracerebral concentrations of drugs that are impermeable to the BBB. In this context, miniosmotic pumps represent an ideal system for constant drug delivery at a fixed known rate that eludes the problem of daily injection stress in animals and that may also be used for direct brain delivery of drugs. Here, we describe a method for miniosmotic pump implantation and post operatory care that should be given to animals in order to successfully apply this technique. We embed the aforementioned experimental paradigm in standard procedures that are used for studying neuroplasticity within the brain of C57BL6 mice. Thus, we exposed animals to 30 min brain infarct and implanted with miniosmotic pumps connected to the skull via a cannula in order to deliver a pro-plasticity drug. Behavioral testing was done during 30 days of treatment. After removal the animals received injections of anterograde tract tracers to analyze neuronal plasticity in the chronic phase of recovery. Results indicated that neuroprotection by the delivered drug was accompanied with increase in motor fibers crossing the midline of the brain at target structures. The results affirm the value of these techniques for drug administration and brain plasticity studies in modern neuroscience. PMID:26863287

  7. A realistic lattice example

    SciTech Connect

    Courant, E.D.; Garren, A.A.

    1985-10-01

    A realistic, distributed interaction region (IR) lattice has been designed that includes new components discussed in the June 1985 lattice workshop. Unlike the test lattices, the lattice presented here includes utility straights and the mechanism for crossing the beams in the experimental straights. Moreover, both the phase trombones and the dispersion suppressors contain the same bending as the normal cells. Vertically separated beams and 6 Tesla, 1-in-1 magnets are assumed. Since the cells are 200 meters long, and have 60 degree phase advance, this lattice has been named RLD1, in analogy with the corresponding test lattice, TLD1. The quadrupole gradient is 136 tesla/meter in the cells, and has similar values in other quadrupoles except in those in the IR`s, where the maximum gradient is 245 tesla/meter. RLD1 has distributed IR`s; however, clustered realistic lattices can easily be assembled from the same components, as was recently done in a version that utilizes the same type of experimental and utility straights as those of RLD1.

  8. Electrokinetic transport in realistic nanochannels

    NASA Astrophysics Data System (ADS)

    Wang, Moran; Liu, Jin; Kang, Qinjun

    2009-11-01

    When an electrolyte solution contacts with a solid surface, the surface will likely be charged through an electrochemical adsorption process. The surface charge in general varies with the local bulk ionic concentration, the pH value and the temperature of the solution, and even with the double layer interactions in the narrow channel. Most of the previous studies are based on a constant zeta potential or surface charge density assumption, which does not reflect the realistic charge status at interfaces and may lead to inaccurate predictions. In this work, we first develop a generalized model for electrochemical boundary conditions on solid-liquid interfaces, which can closely approximate the known experimental properties. We further present nonequilibrium molecular dynamic (NEMD) simulations of electrokinetic transport in nanochannels. We take silica and carbon as examples of channel materials. Both monovalent and multivalent ionic solutions are considered. The electrokinetic transport properties for realistic nanochannels are therefore studied and a multiscale analysis for a new energy conversion device is performed.

  9. Clinical leadership and prevention in practice: is a needs led preventive approach to the delivery of care to improve quality, outcomes and value in primary dental care practice a realistic concept?

    PubMed Central

    2015-01-01

    Background There is a need to improve access to, and the quality of, service delivery in NHS primary dental care. Building public health thinking and leadership capacity in clinicians from primary care teams was seen as an underpinning component to achieving this goal. Clinical teams contributed to service redesign concepts and were contractually supported to embrace a preventive approach. Methods Improvement in quality and preventive focus of dental practice care delivery was explored through determining the impact of several projects, to share how evidence, skill mix and clinical leadership could be utilised in design, implementation and measurement of care outcomes in general dental practice in order to champion and advocate change, during a period of substantial change within the NHS system. The projects were: 1. A needs-led, evidence informed preventive care pathway approach to primary dental care delivery with a focus on quality and outcomes. 2. Building clinical leadership to influence and advocate for improved quality of care; and spread of learning through local professional networks. This comprised two separate projects: improved access for very young children called “Baby Teeth DO Matter” and the production of a clinically led, evidence-based guidance for periodontyal treatment in primary care called “Healthy Gums DO Matter”. Results What worked and what hindered progress, is described. The projects developed understanding of how working with ‘local majorities’ of clinicians influenced, adoption and spread of learning, and the impact in prompting wider policy and contract reform in England. Conclusions The projects identified issues that required change to meet population need. Clinicians were allowed to innovate in an evironment working together with commissioners, patients and public health colleagues. Communication and the development of clinical leadership led to the development of an infrastructure to define care pathways and decision

  10. Non-Sink Dissolution Conditions for Predicting Product Quality and In Vivo Performance of Supersaturating Drug Delivery Systems.

    PubMed

    Sun, Dajun D; Wen, Hong; Taylor, Lynne S

    2016-09-01

    With recent advances in the development of supersaturating oral dosage forms for poorly water-soluble drugs, pharmaceutical scientists are increasingly applying in vitro dissolution testing under non-sink conditions for a direct evaluation of their ability to generate and maintain supersaturation as a predictive surrogate for ensuring product quality and in vivo performance. However, the scientific rationale for developing the appropriate non-sink dissolution methodologies has not been extensively debated. This calls for a comprehensive discussion of recent research efforts on theoretical and experimental considerations of amorphous solubility, liquid-liquid phase separation, and phase transitions of drugs in a supersaturated solution when dissolution testing is performed under supersaturated non-sink conditions. In addition, we outline the concept of "sink index" that quantifies the magnitude of deviations from perfect sink dissolution conditions in the sink/non-sink continuum and some considerations of non-sink dissolution testing for marketed drug products. These factors should be carefully considered in recommending an adequately discriminatory dissolution method in the performance assessment of supersaturating drug delivery systems. PMID:27174227

  11. Testing of Icy-Soil Sample Delivery in Simulated Martian Conditions (Animation)

    NASA Technical Reports Server (NTRS)

    2008-01-01

    [figure removed for brevity, see original site] Click on image for animation

    This movie clip shows testing under simulated Mars conditions on Earth in preparation for NASA's Phoenix Mars Lander using its robotic arm for delivering a sample to the doors of a laboratory oven.

    The icy soil used in the testing flowed easily from the scoop during all tests at Martian temperatures. On Mars, icy soil has stuck to the scoop, a surprise that may be related to composition of the soil at the landing site.

    This testing was done at Honeybee Robotics Spacecraft Mechanisms Corp., New York, which supplied the Phoenix scoop.

    The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASAaE(TM)s Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  12. Can "realist" randomised controlled trials be genuinely realist?

    PubMed

    Van Belle, Sara; Wong, Geoff; Westhorp, Gill; Pearson, Mark; Emmel, Nick; Manzano, Ana; Marchal, Bruno

    2016-01-01

    In this paper, we respond to a paper by Jamal and colleagues published in Trials in October 2015 and take an opportunity to continue the much-needed debate about what applied scientific realism is. The paper by Jamal et al. is useful because it exposes the challenges of combining a realist evaluation approach (as developed by Pawson and Tilley) with the randomised controlled trial (RCT) design.We identified three fundamental differences that are related to paradigmatic differences in the treatment of causation between post-positivist and realist logic: (1) the construct of mechanism, (2) the relation between mediators and moderators on one hand and mechanisms and contexts on the other hand, and (3) the variable-oriented approach to analysis of causation versus the configurational approach.We show how Jamal et al. consider mechanisms as observable, external treatments and how their approach reduces complex causal processes to variables. We argue that their proposed RCT design cannot provide a truly realist understanding. Not only does the proposed realist RCT design not deal with the RCT's inherent inability to "unpack" complex interventions, it also does not enable the identification of the dynamic interplay among the intervention, actors, context, mechanisms and outcomes, which is at the core of realist research. As a result, the proposed realist RCT design is not, as we understand it, genuinely realist in nature. PMID:27387202

  13. Realist evaluation: an immanent critique.

    PubMed

    Porter, Sam

    2015-10-01

    This paper critically analyses realist evaluation, focussing on its primary analytical concepts: mechanisms, contexts, and outcomes. Noting that nursing investigators have had difficulty in operationalizing the concepts of mechanism and context, it is argued that their confusion is at least partially the result of ambiguities, inconsistencies, and contradictions in the realist evaluation model. Problematic issues include the adoption of empiricist and idealist positions, oscillation between determinism and voluntarism, subsumption of agency under structure, and categorical confusion between context and mechanism. In relation to outcomes, it is argued that realist evaluation's adoption of the fact/value distinction prevents it from taking into account the concerns of those affected by interventions. The aim of the paper is to use these immanent critiques of realist evaluation to construct an internally consistent realist approach to evaluation that is more amenable to being operationalized by nursing researchers. PMID:26392234

  14. Generating realistic images using Kray

    NASA Astrophysics Data System (ADS)

    Tanski, Grzegorz

    2004-07-01

    Kray is an application for creating realistic images. It is written in C++ programming language, has a text-based interface, solves global illumination problem using techniques such as radiosity, path tracing and photon mapping.

  15. RAMESES publication standards: realist syntheses

    PubMed Central

    2013-01-01

    Background There is growing interest in realist synthesis as an alternative systematic review method. This approach offers the potential to expand the knowledge base in policy-relevant areas - for example, by explaining the success, failure or mixed fortunes of complex interventions. No previous publication standards exist for reporting realist syntheses. This standard was developed as part of the RAMESES (Realist And MEta-narrative Evidence Syntheses: Evolving Standards) project. The project's aim is to produce preliminary publication standards for realist systematic reviews. Methods We (a) collated and summarized existing literature on the principles of good practice in realist syntheses; (b) considered the extent to which these principles had been followed by published syntheses, thereby identifying how rigor may be lost and how existing methods could be improved; (c) used a three-round online Delphi method with an interdisciplinary panel of national and international experts in evidence synthesis, realist research, policy and/or publishing to produce and iteratively refine a draft set of methodological steps and publication standards; (d) provided real-time support to ongoing realist syntheses and the open-access RAMESES online discussion list so as to capture problems and questions as they arose; and (e) synthesized expert input, evidence syntheses and real-time problem analysis into a definitive set of standards. Results We identified 35 published realist syntheses, provided real-time support to 9 on-going syntheses and captured questions raised in the RAMESES discussion list. Through analysis and discussion within the project team, we summarized the published literature and common questions and challenges into briefing materials for the Delphi panel, comprising 37 members. Within three rounds this panel had reached consensus on 19 key publication standards, with an overall response rate of 91%. Conclusion This project used multiple sources to develop and

  16. Developing an intervention to facilitate family communication about inherited genetic conditions, and training genetic counsellors in its delivery.

    PubMed

    Eisler, Ivan; Ellison, Matthew; Flinter, Frances; Grey, Jo; Hutchison, Suzanne; Jackson, Carole; Longworth, Louise; MacLeod, Rhona; McAllister, Marion; Metcalfe, Alison; Murrells, Trevor; Patch, Christine; Pritchard, Stuart; Robert, Glenn; Rowland, Emma; Ulph, Fiona

    2016-06-01

    Many families experience difficulty in talking about an inherited genetic condition that affects one or more of them. There have now been a number of studies identifying the issues in detail, however few have developed interventions to assist families. The SPRinG collaborative have used the UK Medical Research Council's guidance on Developing and Evaluating Complex Interventions, to work with families and genetic counsellors (GCs) to co-design a psycho-educational intervention to facilitate family communication and promote better coping and adaptation to living with an inherited genetic condition for parents and their children (<18 years). The intervention is modelled on multi-family discussion groups (MFDGs) used in psychiatric settings. The MFDG was developed and tested over three phases. First focus groups with parents, young people, children and health professionals discussed whether MFDG was acceptable and proposed a suitable design. Using evidence and focus group data, the intervention and a training manual were developed and three GCs were trained in its delivery. Finally, a prototype MFDG was led by a family therapist and co-facilitated by the three GCs. Data analysis showed that families attending the focus groups and intervention thought MFDG highly beneficial, and the pilot sessions had a significant impact on their family' functioning. We also demonstrated that it is possible to train GCs to deliver the MFDG intervention. Further studies are now required to test the feasibility of undertaking a definitive randomised controlled trial to evaluate its effectiveness in improving family outcomes before implementing into genetic counselling practice. PMID:26443265

  17. Developing an intervention to facilitate family communication about inherited genetic conditions, and training genetic counsellors in its delivery

    PubMed Central

    Eisler, Ivan; Ellison, Matthew; Flinter, Frances; Grey, Jo; Hutchison, Suzanne; Jackson, Carole; Longworth, Louise; MacLeod, Rhona; McAllister, Marion; Metcalfe, Alison; Murrells, Trevor; Patch, Christine; Pritchard, Stuart; Robert, Glenn; Rowland, Emma; Ulph, Fiona

    2016-01-01

    Many families experience difficulty in talking about an inherited genetic condition that affects one or more of them. There have now been a number of studies identifying the issues in detail, however few have developed interventions to assist families. The SPRinG collaborative have used the UK Medical Research Council's guidance on Developing and Evaluating Complex Interventions, to work with families and genetic counsellors (GCs) to co-design a psycho-educational intervention to facilitate family communication and promote better coping and adaptation to living with an inherited genetic condition for parents and their children (<18 years). The intervention is modelled on multi-family discussion groups (MFDGs) used in psychiatric settings. The MFDG was developed and tested over three phases. First focus groups with parents, young people, children and health professionals discussed whether MFDG was acceptable and proposed a suitable design. Using evidence and focus group data, the intervention and a training manual were developed and three GCs were trained in its delivery. Finally, a prototype MFDG was led by a family therapist and co-facilitated by the three GCs. Data analysis showed that families attending the focus groups and intervention thought MFDG highly beneficial, and the pilot sessions had a significant impact on their family' functioning. We also demonstrated that it is possible to train GCs to deliver the MFDG intervention. Further studies are now required to test the feasibility of undertaking a definitive randomised controlled trial to evaluate its effectiveness in improving family outcomes before implementing into genetic counselling practice. PMID:26443265

  18. Demonstrating a Realistic IP Mission Prototype

    NASA Technical Reports Server (NTRS)

    Rash, James; Ferrer, Arturo B.; Goodman, Nancy; Ghazi-Tehrani, Samira; Polk, Joe; Johnson, Lorin; Menke, Greg; Miller, Bill; Criscuolo, Ed; Hogie, Keith

    2003-01-01

    Flight software and hardware and realistic space communications environments were elements of recent demonstrations of the Internet Protocol (IP) mission concept in the lab. The Operating Missions as Nodes on the Internet (OMNI) Project and the Flight Software Branch at NASA/GSFC collaborated to build the prototype of a representative space mission that employed unmodified off-the-shelf Internet protocols and technologies for end-to-end communications between the spacecraft/instruments and the ground system/users. The realistic elements used in the prototype included an RF communications link simulator and components of the TRIANA mission flight software and ground support system. A web-enabled camera connected to the spacecraft computer via an Ethernet LAN represented an on-board instrument creating image data. In addition to the protocols at the link layer (HDLC), transport layer (UDP, TCP), and network (IP) layer, a reliable file delivery protocol (MDP) at the application layer enabled reliable data delivery both to and from the spacecraft. The standard Network Time Protocol (NTP) performed on-board clock synchronization with a ground time standard. The demonstrations of the prototype mission illustrated some of the advantages of using Internet standards and technologies for space missions, but also helped identify issues that must be addressed. These issues include applicability to embedded real-time systems on flight-qualified hardware, range of applicability of TCP, and liability for and maintenance of commercial off-the-shelf (COTS) products. The NASA Earth Science Technology Office (ESTO) funded the collaboration to build and demonstrate the prototype IP mission.

  19. Biodegradable nanoparticles for protein delivery: analysis of preparation conditions on particle morphology and protein loading, activity and sustained release properties.

    PubMed

    Coleman, Jason; Lowman, Anthony

    2012-01-01

    PLGA particles have been extensively used as a sustained drug-delivery system, but there are multiple drawbacks when delivering proteins. The focus of this work is to address the most significant disadvantages to the W/O/W double emulsion procedure and demonstrate that simple changes to this procedure can have significant changes to particle size and dispersity and considerable improvements to protein loading, activity and sustained active protein release. A systematic approach was taken to analyze the effects of the following variables: solvent miscibility (dichloromethane (DCM), ethyl acetate, acetone), homogenization speed (10 000-25 000 rpm), PLGA concentration (10-30 mg/ml) and additives in both the organic (sucrose acetate isobutyrate (SAIB)) and aqueous (bovine serum albumin (BSA)) phases. Increasing solvent miscibility decreased particle size, dispersity and protein denaturation, while maintaining adequate protein loading. Increasing solvent miscibility also lowered the impact of homogenization on particle size and dispersity and protein activity. Changes to PLGA concentration demonstrated a minimum impact on particle size and dispersity, but showed an inverse relationship between protein encapsulation efficiency and particle protein weight percent. Most particles tested provided sustained release of active protein over 60 days. Increasing solvent miscibility resulted in increases in the percent of active protein released. When subjected to synthesis conditions with DCM as the solvent, BSA as a stabilizer resulted in the maximum stabilization of protein at a concentration of 100 mg/ml. At this concentration, BSA allowed for increases in the total amount of active protein delivered for all three solvents. The benefit of SAIB was primarily increased protein loading. PMID:21639993

  20. Laser-induced interstitial thermotherapy via a single-needle delivery system: Optimal conditions of ablation, pathological and ultrasonic changes.

    PubMed

    Zhang, Yan-Rong; Fang, Ling-Yun; Yu, Cheng; Sun, Zhen-Xing; Huang, Yan; Chen, Juan; Guo, Tao; Xiang, Fei-Xiang; Wang, Jing; Lu, Cheng-Fa; Yan, Tian-Wei; Lv, Qing; Xie, Ming-Xing

    2015-08-01

    This study aimed to examine the optimal conditions of laser-induced interstitial thermotherapy (LITT) via a single-needle delivery system, and the ablation-related pathological and ultrasonic changes. Ultrasound (US)-guided LITT (EchoLaser system) was performed at the output power of 2-4 Wattage (W) for 1-10 min in ex vivo bovine liver. Based on the results of the ex vivo study, the output power of 3 and 4 W with different durations was applied to in vivo rabbit livers (n=24), and VX2 tumors implanted in the hind limbs of rabbits (n=24). The ablation area was histologically determined by hematoxylin-eosin (HE) staining. Traditional US and contrast enhanced ultrasound (CEUS) were used to evaluate the treatment outcomes. The results showed: (1) In the bovine liver, ablation disruption was grossly seen, including a strip-like ablation crater, a carbonization zone anteriorly along the fiber tip, and a surrounding gray-white coagulation zone. The coagulation area, 1.2 cm in length and 1.0 cm in width, was formed in the bovine liver subjected to the ablation at 3 W for 5 min and 4 W for 4 min, and it extended slightly with the ablation time. (2) In the rabbit liver, after LITT at 3 W for 3 min and more, the coagulation area with length greater than or equal to 1.2 cm, and width greater than or equal to 1.0 cm, was found. Similar coagulation area was seen in the implanted VX2 carcinoma at 3 W for 5 min. (3) Gross examination of the liver and carcinoma showed three distinct regions: ablation crater/carbonization, coagulation and congestion distributed from the center outwards. (4) Microscopy revealed four zones after LITT, including ablation crater/carbonization, coagulation, edema and congestion from the center outwards. A large area with coagulative necrosis was observed around a vessel in the peripheral area with edema and hyperemia. (5) The size of coagulation was consistent well to the CEUS findings. It was concluded that EchoLaser system at low power can produce a

  1. Electromagnetic Scattering from Realistic Targets

    NASA Technical Reports Server (NTRS)

    Lee, Shung- Wu; Jin, Jian-Ming

    1997-01-01

    The general goal of the project is to develop computational tools for calculating radar signature of realistic targets. A hybrid technique that combines the shooting-and-bouncing-ray (SBR) method and the finite-element method (FEM) for the radiation characterization of microstrip patch antennas in a complex geometry was developed. In addition, a hybridization procedure to combine moment method (MoM) solution and the SBR method to treat the scattering of waveguide slot arrays on an aircraft was developed. A list of journal articles and conference papers is included.

  2. Optomechanical considerations for realistic tolerancing

    NASA Astrophysics Data System (ADS)

    Herman, Eric; Sasián, José; Youngworth, Richard N.

    2013-09-01

    Optical tolerancing simulation has improved so that the modeling of optomechanical accuracy can better predict as-built performance. A key refinement being proposed within this paper is monitoring formal interference fits and checking lens elements within their mechanical housings. Without proper checks, simulations may become physically unrealizable and pessimistic, thereby resulting in lower simulated yields. An improved simulation method has been defined and demonstrated in this paper with systems that do not have barrel constraints. The demonstration cases clearly show the trend of the beneficial impact with yield results, as a yield increase of 36.3% to 39.2% is garnered by one example. Considerations in simulating the realistic optomechanical system will assist in controlling cost and providing more accurate simulation results.

  3. Realistic Solar Surface Convection Simulations

    NASA Technical Reports Server (NTRS)

    Stein, Robert F.; Nordlund, Ake

    2000-01-01

    We perform essentially parameter free simulations with realistic physics of convection near the solar surface. We summarize the physics that is included and compare the simulation results with observations. Excellent agreement is obtained for the depth of the convection zone, the p-mode frequencies, the p-mode excitation rate, the distribution of the emergent continuum intensity, and the profiles of weak photospheric lines. We describe how solar convection is nonlocal. It is driven from a thin surface thermal boundary layer where radiative cooling produces low entropy gas which forms the cores of the downdrafts in which most of the buoyancy work occurs. We show that turbulence and vorticity are mostly confined to the intergranular lanes and underlying downdrafts. Finally, we illustrate our current work on magneto-convection.

  4. Realistic glottal motion and airflow rate during human breathing.

    PubMed

    Scheinherr, Adam; Bailly, Lucie; Boiron, Olivier; Lagier, Aude; Legou, Thierry; Pichelin, Marine; Caillibotte, Georges; Giovanni, Antoine

    2015-09-01

    The glottal geometry is a key factor in the aerosol delivery efficiency for treatment of lung diseases. However, while glottal vibrations were extensively studied during human phonation, the realistic glottal motion during breathing is poorly understood. Therefore, most current studies assume an idealized steady glottis in the context of respiratory dynamics, and thus neglect the flow unsteadiness related to this motion. This is particularly important to assess the aerosol transport mechanisms in upper airways. This article presents a clinical study conducted on 20 volunteers, to examine the realistic glottal motion during several breathing tasks. Nasofibroscopy was used to investigate the glottal geometrical variations simultaneously with accurate airflow rate measurements. In total, 144 breathing sequences of 30s were recorded. Regarding the whole database, two cases of glottal time-variations were found: "static" or "dynamic" ones. Typically, the peak value of glottal area during slow breathing narrowed from 217 ± 54 mm(2) (mean ± STD) during inspiration, to 178 ± 35 mm(2) during expiration. Considering flow unsteadiness, it is shown that the harmonic approximation of the airflow rate underevaluates the inertial effects as compared to realistic patterns, especially at the onset of the breathing cycle. These measurements provide input data to conduct realistic numerical simulations of laryngeal airflow and particle deposition. PMID:26159687

  5. Realist RCTs of complex interventions - an oxymoron.

    PubMed

    Marchal, Bruno; Westhorp, Gill; Wong, Geoff; Van Belle, Sara; Greenhalgh, Trisha; Kegels, Guy; Pawson, Ray

    2013-10-01

    Bonell et al. discuss the challenges of carrying out randomised controlled trials (RCTs) to evaluate complex interventions in public health, and consider the role of realist evaluation in enhancing this design (Bonell, Fletcher, Morton, Lorenc, & Moore, 2012). They argue for a "synergistic, rather than oppositional relationship between realist and randomised evaluation" and that "it is possible to benefit from the insights provided by realist evaluation without relinquishing the RCT as the best means of examining intervention causality." We present counter-arguments to their analysis of realist evaluation and their recommendations for realist RCTs. Bonell et al. are right to question whether and how (quasi-)experimental designs can be improved to better evaluate complex public health interventions. However, the paper does not explain how a research design that is fundamentally built upon a positivist ontological and epistemological position can be meaningfully adapted to allow it to be used from within a realist paradigm. The recommendations for "realist RCTs" do not sufficiently take into account important elements of complexity that pose major challenges for the RCT design. They also ignore key tenets of the realist evaluation approach. We propose that the adjective 'realist' should continue to be used only for studies based on a realist philosophy and whose analytic approach follows the established principles of realist analysis. It seems more correct to call the approach proposed by Bonell and colleagues 'theory informed RCT', which indeed can help in enhancing RCTs. PMID:23850482

  6. Behavior of vitamin E acetate delivery systems under simulated gastrointestinal conditions: lipid digestion and bioaccessibility of low-energy nanoemulsions.

    PubMed

    Mayer, Sinja; Weiss, Jochen; McClements, David Julian

    2013-08-15

    Colloidal delivery systems are needed to incorporate oil-soluble vitamins into aqueous-based foods and beverage products. In this study, we encapsulated vitamin E acetate into oil-in-water nanoemulsions produced using either a low-energy method (Emulsion Phase Inversion, EPI) or a high energy method (microfluidization). Oil-in-water nanoemulsions (d<200 nm) could be produced using both low- and high-energy methods from a non-ionic surfactant (Tween 80) and medium chain triglycerides (MCTs). The influence of surfactant-to-oil ratio (SOR) on lipid digestion and vitamin bioaccessibility of EPI nanoemulsions was determined using a gastrointestinal tract (GIT) model that simulated the mouth, stomach, and small intestine. There were increases in the size and negative charge of the oil droplets after passage through the GIT, which was attributed to droplet coalescence and changes in interfacial composition. The rate and extent of lipid digestion decreased with increasing surfactant concentration, but the bioaccessibility of vitamin E acetate was high in all of the samples (>95%). No appreciable influence of the preparation method (low-energy versus high-energy) on lipid digestion and vitamin bioaccessibility was observed. The major advantage of the EPI method for forming nanoemulsions is that no expensive equipment is required, but relatively high surfactant concentrations are needed compared to microfluidization. PMID:23721832

  7. Role of context in care transition interventions for medically complex older adults: a realist synthesis protocol

    PubMed Central

    Pitzul, Kristen B; Lane, Natasha E; Voruganti, Teja; Khan, Anum I; Innis, Jennifer; Wodchis, Walter P; Baker, G Ross

    2015-01-01

    Introduction Approximately 30–50% of older adults have two or more conditions and are referred to as multimorbid or complex patients. These patients often require visits to various healthcare providers in a number of settings and are therefore susceptible to fragmented healthcare delivery while transitioning to receive care. Care transition interventions have been implemented to improve continuity of care, however, current evidence suggests that some interventions or components of interventions are only effective within certain contexts. There is therefore a need to unpack the mechanisms of how and within which contexts care transition interventions and their components are effective. Realist review is a synthesis method that explains how complex programmes work within various contexts. The purpose of this study is to explain the effect of context on the activities and mechanisms of care transition interventions in medically complex older adults using a realist review approach. Methods and analysis This synthesis will be guided by Pawson and colleagues’ 2004 and 2005 protocols for conducting realist reviews. The underlying theories of care transition interventions were determined based on an initial literature search using relevant databases. English language peer-reviewed studies published after 1993 will be included. Several relevant databases will be searched using medical subject headings and text terms. A screening form will be piloted and titles, abstracts and full text of potentially relevant articles will be screened in duplicate. Abstracted data will include study characteristics, intervention type, contextual factors, intervention activities and underlying mechanisms. Patterns in Context-Activity-Mechanism-Outcome (CAMO) configurations will be reported. Ethics and dissemination Internal knowledge translation activities will occur throughout the review and existing partnerships will be leveraged to disseminate findings to frontline staff, hospital

  8. Compact entanglement distillery using realistic quantum memories

    NASA Astrophysics Data System (ADS)

    Chakhmakhchyan, Levon; Guérin, Stéphane; Nunn, Joshua; Datta, Animesh

    2013-10-01

    We adopt the beam-splitter model for losses to analyze the performance of a recent compact continuous-variable entanglement distillation protocol [A. Datta , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.108.060502 108, 060502 (2012)] implemented using realistic quantum memories. We show that the decoherence undergone by a two-mode squeezed state while stored in a quantum memory can strongly modify the results of the preparatory step of the protocol. We find that the well-known method for locally increasing entanglement, phonon subtraction, may not result in entanglement gain when losses are taken into account. Thus, we investigate the critical number mc of phonon subtraction attempts from the matter modes of the quantum memory. If the initial state is not de-Gaussified within mc attempts, the protocol should be restarted to obtain any entanglement increase. Moreover, the condition mc>1 implies an additional constraint on the subtraction beam-splitter interaction transmissivity, viz., it should be about 50% for a wide range of protocol parameters. Additionally, we consider the average entanglement rate, which takes into account both the unavoidable probabilistic nature of the protocol and its possible failure as a result of a large number of unsuccessful subtraction attempts. We find that a higher value of the average entanglement can be achieved by increasing the subtraction beam-splitter interaction transmissivity. We conclude that the compact distillation protocol with the practical constraints coming from realistic quantum memories allows a feasible experimental realization within existing technologies.

  9. Gravity waves in a realistic atmosphere.

    NASA Technical Reports Server (NTRS)

    Liemohn, H. B.; Midgley, J. E.

    1966-01-01

    Internal atmospheric gravity waves in isothermal medium, solving hydrodynamic equations, determining wave propagation in realistic atmosphere for range of wave parameters, wind amplitude, reflected energy, etc

  10. Setting Standards at the Forefront of Delivery System Reform: Aligning Care Coordination Quality Measures for Multiple Chronic Conditions

    PubMed Central

    DuGoff, Eva H.; Dy, Sydney; Giovannetti, Erin R.; Leff, Bruce; Boyd, Cynthia M.

    2015-01-01

    The primary study objective is to assess how three major health reform care coordination initiatives (Accountable Care Organizations, Independence at Home, and Community-based Care Transitions) measure concepts critical to care coordination for people with multiple chronic conditions. We find that there are major differences in quality measurement across these three large and politically important programs. Quality measures currently used or proposed for these new health reform-related programs addressing care coordination primarily capture continuity of care. Other key areas of care coordination, such as care transitions, patient-centeredness, and cross-cutting care across multiple conditions are infrequently addressed. The lack of a comprehensive and consistent measure set for care coordination will pose challenges for health care providers and policymakers who seek, respectively, to provide and reward well-coordinated care. In addition, this heterogeneity in measuring care coordination quality will generate new information, but will inhibit comparisons between these care coordination programs. PMID:24004040

  11. Setting standards at the forefront of delivery system reform: aligning care coordination quality measures for multiple chronic conditions.

    PubMed

    DuGoff, Eva H; Dy, Sydney; Giovannetti, Erin R; Leff, Bruce; Boyd, Cynthia M

    2013-01-01

    The primary study objective is to assess how three major health reform care coordination initiatives (Accountable Care Organizations, Independence at Home, and Community-Based Care Transitions) measure concepts critical to care coordination for people with multiple chronic conditions. We find that there are major differences in quality measurement across these three large and politically important programs. Quality measures currently used or proposed for these new health reform-related programs addressing care coordination primarily capture continuity of care. Other key areas of care coordination, such as care transitions, patient-centeredness, and cross-cutting care across multiple conditions are infrequently addressed. The lack of a comprehensive and consistent measure set for care coordination will pose challenges for healthcare providers and policy makers who seek, respectively, to provide and reward well-coordinated care. In addition, this heterogeneity in measuring care coordination quality will generate new information, but will inhibit comparisons between these care coordination programs. PMID:24004040

  12. Alveolar mechanics using realistic acinar models

    NASA Astrophysics Data System (ADS)

    Kumar, Haribalan; Lin, Ching-Long; Tawhai, Merryn H.; Hoffman, Eric A.

    2009-11-01

    Accurate modeling of the mechanics in terminal airspaces of the lung is desirable for study of particle transport and pathology. The flow in the acinar region is traditionally studied by employing prescribed boundary conditions to represent rhythmic breathing and volumetric expansion. Conventional models utilize simplified spherical or polygonal units to represent the alveolar duct and sac. Accurate prediction of flow and transport characteristics may require geometries reconstructed from CT-based images and serve to understand the importance of physiologically realistic representation of the acinus. In this effort, we present a stabilized finite element framework, supplemented with appropriate boundary conditions at the alveolar mouth and septal borders for simulation of the alveolar mechanics and the resulting airflow. Results of material advection based on Lagrangian tracking are presented to complete the study of transport and compare the results with simplified acinar models. The current formulation provides improved understanding and realization of a dynamic framework for parenchymal mechanics with incorporation of alveolar pressure and traction stresses.

  13. Realistic simulations of coaxial atomisation

    NASA Astrophysics Data System (ADS)

    Zaleski, Stephane; Fuster, Daniel; Arrufat Jackson, Tomas; Ling, Yue; Cenni, Matteo; Scardovelli, Ruben; Tryggvason, Gretar

    2015-11-01

    We discuss advances in the methodology for Direct Numerical Simulations of coaxial atomization in typical experimental conditions. Such conditions are extremely demanding for the numerical methods. The key difficulty seems to be the combination of high density ratios, surface tension, and large Reynolds numbers. We explore how using a momentum-conserving Volume-Of-Fluid scheme allows to improve the stability and accuracy of the simulations. We show computational evidence that the use of momentum conserving methods allows to reduce the required number of grid points by an order of magnitude in the simple case of a falling rain drop. We then apply these ideas to coaxial atomization. We show that in moderate-size simulations in air-water conditions close to real experiments, instabilities are still present and then discuss ways to fix them. Among those, removing small VOF debris and improving the time-stepping scheme are two important directions.The accuracy of the simulations is then discussed in comparison with experimental results and in particular the angle of ejection of the structures. The code used for this research is free and distributed at http://parissimulator.sf.net.

  14. Realist complex intervention science: Applying realist principles across all phases of the Medical Research Council framework for developing and evaluating complex interventions

    PubMed Central

    Fletcher, Adam; Jamal, Farah; Moore, Graham; Evans, Rhiannon E.; Murphy, Simon; Bonell, Chris

    2016-01-01

    The integration of realist evaluation principles within randomised controlled trials (‘realist RCTs’) enables evaluations of complex interventions to answer questions about what works, for whom and under what circumstances. This allows evaluators to better develop and refine mid-level programme theories. However, this is only one phase in the process of developing and evaluating complex interventions. We describe and exemplify how social scientists can integrate realist principles across all phases of the Medical Research Council framework. Intervention development, modelling, and feasibility and pilot studies need to theorise the contextual conditions necessary for intervention mechanisms to be activated. Where interventions are scaled up and translated into routine practice, realist principles also have much to offer in facilitating knowledge about longer-term sustainability, benefits and harms. Integrating a realist approach across all phases of complex intervention science is vital for considering the feasibility and likely effects of interventions for different localities and population subgroups. PMID:27478401

  15. Preventing epileptogenesis: A realistic goal?

    PubMed

    Terrone, Gaetano; Pauletti, Alberto; Pascente, Rosaria; Vezzani, Annamaria

    2016-08-01

    The definition of the pathologic process of epileptogenesis has considerably changed over the past few years due to a better knowledge of the dynamics of the associated molecular modifications and to clinical and experimental evidence of progression of the epileptic condition beyond the occurrence of the first seizures. Interference with this chronic process may lead to the development of novel preventive therapies which are still lacking. Notably, epileptogenesis is often associated with comorbid behaviors which are now considered primary outcome measures for novel therapeutics. Anti-epileptogenic interventions may improve not only seizure onset and their frequency and severity but also comorbidities and cell loss, and when applied after the onset of the disease may provide disease-modifying effects by favorably modifying the disease course. In the preclinical arena, several novel targets for anti-epileptogenic and disease-modifying interventions are being characterized and validated in rodent models of epileptogenesis. To move proof-of-concept anti-epileptogenesis studies to validation in preclinical trials and eventually to clinical translation is a challenging task which would be greatly facilitated by the development of non invasive biomarkers of epileptogenesis. Biomarker discovery together with testing potential novel drugs would provide a major advance in the treatment of human epilepsy beyond the pure symptomatic control of seizures. PMID:27173399

  16. MEMS: Enabled Drug Delivery Systems.

    PubMed

    Cobo, Angelica; Sheybani, Roya; Meng, Ellis

    2015-05-01

    Drug delivery systems play a crucial role in the treatment and management of medical conditions. Microelectromechanical systems (MEMS) technologies have allowed the development of advanced miniaturized devices for medical and biological applications. This Review presents the use of MEMS technologies to produce drug delivery devices detailing the delivery mechanisms, device formats employed, and various biomedical applications. The integration of dosing control systems, examples of commercially available microtechnology-enabled drug delivery devices, remaining challenges, and future outlook are also discussed. PMID:25703045

  17. PET-based dose delivery verification in proton therapy: a GATE based simulation study of five PET system designs in clinical conditions

    NASA Astrophysics Data System (ADS)

    Robert, Charlotte; Fourrier, Nicolas; Sarrut, David; Stute, Simon; Gueth, Pierre; Grevillot, Loïc; Buvat, Irène

    2013-10-01

    PET is a promising technique for in vivo treatment verification in hadrontherapy. Three main PET geometries dedicated to in-beam treatment monitoring have been proposed in the literature: the dual-head PET geometry, the OpenPET geometry and the slanted-closed ring geometry. The aim of this work is to characterize the performance of two of these dedicated PET detectors in realistic clinical conditions. Several configurations of the dual-head PET and OpenPET systems were simulated using GATE v6.2. For the dual-head configuration, two aperture angles (15° and 45°) were studied. For the OpenPET system, two gaps between rings were investigated (110 and 160 mm). A full-ring PET system was also simulated as a reference. After preliminary evaluation of the sensitivity and spatial resolution using a Derenzo phantom, a real small-field head and neck treatment plan was simulated, with and without introducing patient displacements. No wash-out was taken into account. 3D maps of the annihilation photon locations were deduced from the PET data acquired right after the treatment session (5 min acquisition) using a dedicated OS-EM reconstruction algorithm. Detection sensitivity at the center of the field-of-view (FOV) varied from 5.2% (45° dual-head system) to 7.0% (full-ring PET). The dual-head systems had a more uniform efficiency within the FOV than the OpenPET systems. The spatial resolution strongly depended on the location within the FOV for the ϕ = 45° dual-head system and for the two OpenPET systems. All investigated architectures identified the magnitude of mispositioning introduced in the simulations within a 1.5 mm accuracy. The variability on the estimated mispositionings was less than 2 mm for all PET systems.

  18. TOWARD A REALISTIC PULSAR MAGNETOSPHERE

    SciTech Connect

    Kalapotharakos, Constantinos; Kazanas, Demosthenes; Harding, Alice

    2012-04-10

    We present the magnetic and electric field structures and the currents and charge densities of pulsar magnetospheres that do not obey the ideal condition, E {center_dot} B = 0. Since the acceleration of particles and the production of radiation require the presence of an electric field component parallel to the magnetic field, E{sub ||}, the structure of non-ideal pulsar magnetospheres is intimately related to the production of pulsar radiation. Therefore, knowledge of the structure of non-ideal pulsar magnetospheres is important because their comparison (including models for the production of radiation) with observations will delineate the physics and the parameters underlying the pulsar radiation problem. We implement a variety of prescriptions that support non-zero values for E{sub ||} and explore their effects on the structure of the resulting magnetospheres. We produce families of solutions that span the entire range between the vacuum and the (ideal) force-free electrodynamic solutions. We also compute the amount of dissipation as a fraction of the Poynting flux for pulsars of different angles between the rotation and magnetic axes and conclude that this is at most 20%-40% (depending on the non-ideal prescription) in the aligned rotator and 10% in the perpendicular one. We present also the limiting solutions with the property J = {rho}c and discuss their possible implication on the determination of the 'on/off' states of the intermittent pulsars. Finally, we find that solutions with values of J greater than those needed to null E{sub ||} locally produce oscillations, potentially observable in the data.

  19. Towards a Realistic Pulsar Magnetosphere

    NASA Technical Reports Server (NTRS)

    Kalapotharakos, Constantinos; Kazanas, Demosthenes; Harding, Alice; Contopoulos, Ioannis

    2012-01-01

    We present the magnetic and electric field structures as well as the currents ami charge densities of pulsar magnetospberes which do not obey the ideal condition, E(raised dot) B = O. Since the acceleration of particles and the production of radiation requires the presence of an electric field component parallel to the magnetic field, E(sub ll) the structure of non-Ideal pulsar magnetospheres is intimately related to the production of pulsar radiation. Therefore, knowledge of the structure of non-Ideal pulsar maglletospheres is important because their comparison (including models for t he production of radiation) with observations will delineate the physics and the parameters underlying the pulsar radiation problem. We implement a variety of prescriptions that support nonzero values for E(sub ll) and explore their effects on the structure of the resulting magnetospheres. We produce families of solutions that span the entire range between the vacuum and the (ideal) Force-Free Electrodynamic solutions. We also compute the amount of dissipation as a fraction of the Poynting flux for pulsars of different angles between the rotation and magnetic axes and conclude that tltis is at most 20-40% (depending on t he non-ideal prescription) in the aligned rotator and 10% in the perpendicular one. We present also the limiting solutions with the property J = pc and discuss their possible implicatioll on the determination of the "on/ off" states of the intermittent pulsars. Finally, we find that solutions with values of J greater than those needed to null E(sub ll) locally produce oscillations, potentially observable in the data.

  20. Effect of simulated gastrointestinal conditions on drug release from pectin/ethylcellulose as film coating for drug delivery to the colon.

    PubMed

    Ahmed, I S

    2005-05-01

    The aim of this work was to investigate the effect of acidic pH representative of gastric fluid on the release of 5-aminosalicylic acid from beads coated with pectin/ethylcellulose as film coating intended for drug delivery to the colon, in media mimicking the lower gastrointestinal (GI) tract and representative of colonic conditions. In this work, the in vitro incubation of the beads in acid medium was found to influence the hydration and the swelling characteristics of pectin after transfer into simulated intestinal fluid and simulated cecal fluid containing pectinolytic enzymes. Moreover, the drug release profiles from the beads in simulated intestinal fluid after incubation for 2 h or 30 min in simulated gastric fluid vs. no acid incubation were found to be very different. The in vitro degradation of pectin in the coat by pectinolytic enzymes in simulated cecal fluid depended on whether the beads were placed in simulated gastric fluid prior to testing in simulated intestinal fluid. The percentage drug release also depended on the ratio of pectin to ethylcellulose in the coat. PMID:16093212

  1. Development of a realistic human airway model.

    PubMed

    Lizal, Frantisek; Elcner, Jakub; Hopke, Philip K; Jedelsky, Jan; Jicha, Miroslav

    2012-03-01

    Numerous models of human lungs with various levels of idealization have been reported in the literature; consequently, results acquired using these models are difficult to compare to in vivo measurements. We have developed a set of model components based on realistic geometries, which permits the analysis of the effects of subsequent model simplification. A realistic digital upper airway geometry except for the lack of an oral cavity has been created which proved suitable both for computational fluid dynamics (CFD) simulations and for the fabrication of physical models. Subsequently, an oral cavity was added to the tracheobronchial geometry. The airway geometry including the oral cavity was adjusted to enable fabrication of a semi-realistic model. Five physical models were created based on these three digital geometries. Two optically transparent models, one with and one without the oral cavity, were constructed for flow velocity measurements, two realistic segmented models, one with and one without the oral cavity, were constructed for particle deposition measurements, and a semi-realistic model with glass cylindrical airways was developed for optical measurements of flow velocity and in situ particle size measurements. One-dimensional phase doppler anemometry measurements were made and compared to the CFD calculations for this model and good agreement was obtained. PMID:22558834

  2. Research on ultra-realistic communications

    NASA Astrophysics Data System (ADS)

    Enami, Kazumasa

    2009-05-01

    A future communication method enabled by information communications technology- ultra-realistic communication - is now being investigated in Japan and research and development of the various technologies required for its realization is being conducted, such as ultra-high definition TV, 3DTV, super surround sound reproduction and multi-sensory communication including touch and smell. An organization called the Ultra-Realistic Communications Forum (URCF) was also established for the effective promotion of R&D and the standardization of relating technologies. This document explains the activities of the URCF by industry, academia and government, and introduces researches on ultra-realistic communications in the National Institute of Information and Communications Technology (NICT).

  3. Keeping It Real: How Realistic Does Realistic Fiction for Children Need to Be?

    ERIC Educational Resources Information Center

    O'Connor, Barbara

    2010-01-01

    O'Connor, an author of realistic fiction for children, shares her attempts to strike a balance between carefree, uncensored, authentic, realistic writing and age-appropriate writing. Of course, complicating that balancing act is the fact that what seems age-appropriate to her might not seem so to everyone. O'Connor suggests that while it may be…

  4. Spatial Visualization by Realistic 3D Views

    ERIC Educational Resources Information Center

    Yue, Jianping

    2008-01-01

    In this study, the popular Purdue Spatial Visualization Test-Visualization by Rotations (PSVT-R) in isometric drawings was recreated with CAD software that allows 3D solid modeling and rendering to provide more realistic pictorial views. Both the original and the modified PSVT-R tests were given to students and their scores on the two tests were…

  5. Making a Literature Methods Course "Realistic."

    ERIC Educational Resources Information Center

    Lewis, William J.

    Recognizing that it can be a challenge to make an undergraduate literature methods course realistic, a methods instructor at a Michigan university has developed three major and several minor activities that have proven effective in preparing pre-student teachers for the "real world" of teaching and, at the same time, have been challenging and…

  6. Satellite Maps Deliver More Realistic Gaming

    NASA Technical Reports Server (NTRS)

    2013-01-01

    When Redwood City, California-based Electronic Arts (EA) decided to make SSX, its latest snowboarding video game, it faced challenges in creating realistic-looking mountains. The solution was NASA's ASTER Global Digital Elevation Map, made available by the Jet Propulsion Laboratory, which EA used to create 28 real-life mountains from 9 different ranges for its award-winning game.

  7. Improving Intuition Skills with Realistic Mathematics Education

    ERIC Educational Resources Information Center

    Hirza, Bonita; Kusumah, Yaya S.; Darhim; Zulkardi

    2014-01-01

    The intention of the present study was to see the improvement of students' intuitive skills. This improvement was seen by comparing the Realistic Mathematics Education (RME)-based instruction with the conventional mathematics instruction. The subject of this study was 164 fifth graders of elementary school in Palembang. The design of this study…

  8. Project REALISTIC: Determining Literacy Demands of Jobs.

    ERIC Educational Resources Information Center

    Sticht, Thomas C.; Kern, Richard P.

    1971-01-01

    REALISTIC is an acronym based upon the three literacy skills areas studied--REAding, LIStening, and ArithmeTIC. The general objectives of the project are: (1) to provide information concerning the demands for reading, listening, and arithmetic skills in several major military occupational specialties (MOSS), and (2) to provide information and…

  9. Realistic Portrayal of Aging. An Annotated Bibliography.

    ERIC Educational Resources Information Center

    Dodson, Anita E.; Hause, Judith B.

    This annotated bibliography cites selected reading materials for all age levels that present aging and the aged realistically with a full range of human behaviors. The listing is meant to serve as a resource to educators who wish to develop positive attitudes in children and in adolescents about the elderly and about themselves. Educators should…

  10. Faculty Development for Educators: A Realist Evaluation

    ERIC Educational Resources Information Center

    Sorinola, Olanrewaju O.; Thistlethwaite, Jill; Davies, David; Peile, Ed

    2015-01-01

    The effectiveness of faculty development (FD) activities for educators in UK medical schools remains underexplored. This study used a realist approach to evaluate FD and to test the hypothesis that motivation, engagement and perception are key mechanisms of effective FD activities. The authors observed and interviewed 33 course participants at one…

  11. Coping with changing conditions: alternative strategies for the delivery of maternal and child health and family planning services in Dhaka, Bangladesh.

    PubMed Central

    Routh, S.; el Arifeen, S.; Jahan, S. A.; Begum, A.; Thwin, A. A.; Baqui, A. H.

    2001-01-01

    The door-to-door distribution of contraceptives and information on maternal and child health and family planning (MCH-FP) services, through bimonthly visits to eligible couples by trained fieldworkers, has been instrumental in increasing the contraceptive prevalence rate and immunization coverage in Bangladesh. The doorstep delivery strategy, however, is labour-intensive and costly. More cost-effective service delivery strategies are needed, not only for family planning services but also for a broader package of reproductive and other essential health services. Against this backdrop, operations research was conducted by the Centre for Health and Population Research at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B) from January 1996 to May 1997, in collaboration with government agencies and a leading national nongovernmental organization, with a view to developing and field-testing alternative approaches to the delivery of MCH-FP services in urban areas. Two alternative strategies featuring the withdrawal of home-based distribution and the delivery of basic health care from fixed-site facilities were tested in two areas of Dhaka. The clinic-based service delivery strategy was found to be a feasible alternative to the resource-intensive doorstep system in urban Dhaka. It did not adversely affect programme performance and it allowed the needs of clients to be addressed holistically through a package of essential health and family planning services. PMID:11242821

  12. "easyMine" - realistic and systematic mine detection simulation tooltion

    NASA Astrophysics Data System (ADS)

    Böttger, U.; Beier, K.; Biering, B.; Müller, C.; Peichl, M.; Spyra, W.

    2004-05-01

    Mine detection is to date mainly performed with metal detectors, although new methods for UXO detection are explored worldwide. The main problem for the mine detection to date is, that there exist some ideas of which sensor combinations could yield a high score, but until now there is no systematic analysis of mine detection methods together with realistic environmental conditions to conclude on a physically and technically optimized sensor combination. This gap will be removed by a project "easyMine" (Realistic and systematic Mine Detection Simulation Tool) which will result in a simulation tool for optimizing land mine detection in a realistic mine field. The project idea for this software tool is presented, that will simulate the closed chain of mine detection, including the mine in its natural environment, the sensor, the evaluation and application of the measurements by an user. The tool will be modularly designed. Each chain link will be an independent, exchangeable sub- module and will describe a stand alone part of the whole mine detection procedure. The advantage of the tool will be the evaluation of very different kinds of sensor combinations in relation of their real potential for mine detection. Three detection methods (metal detector, GPR and imaging IR-radiometry) will be explained to be introduced into the easyMine software tool in a first step. An actual example for land mine detection problem will be presented and approaches for solutions with easyMine will be shown.

  13. Measurements of lateral penumbra for uniform scanning proton beams under various beam delivery conditions and comparison to the XiO treatment planning system

    SciTech Connect

    Rana, Suresh; Zeidan, Omar; Ramirez, Eric; Rains, Michael; Gao, Junfang; Zheng, Yuanshui

    2013-09-15

    Purpose: The main purposes of this study were to (1) investigate the dependency of lateral penumbra (80%–20% distance) of uniform scanning proton beams on various factors such as air gap, proton range, modulation width, compensator thickness, and depth, and (2) compare the lateral penumbra calculated by a treatment planning system (TPS) with measurements.Methods: First, lateral penumbra was measured using solid–water phantom and radiographic films for (a) air gap, ranged from 0 to 35 cm, (b) proton range, ranged from 8 to 30 cm, (c) modulation, ranged from 2 to 10 cm, (d) compensator thickness, ranged from 0 to 20 cm, and (e) depth, ranged from 7 to 15 cm. Second, dose calculations were computed in a virtual water phantom using the XiO TPS with pencil beam algorithm for identical beam conditions and geometrical configurations that were used for the measurements. The calculated lateral penumbra was then compared with the measured one for both the horizontal and vertical scanning magnets of our uniform scanning proton beam delivery system.Results: The results in the current study showed that the lateral penumbra of horizontal scanning magnet was larger (up to 1.4 mm for measurement and up to 1.0 mm for TPS) compared to that of vertical scanning magnet. Both the TPS and measurements showed an almost linear increase in lateral penumbra with increasing air gap as it produced the greatest effect on lateral penumbra. Lateral penumbra was dependent on the depth and proton range. Specifically, the width of lateral penumbra was found to be always lower at shallower depth than at deeper depth within the spread out Bragg peak (SOBP) region. The lateral penumbra results were less sensitive to the variation in the thickness of compensator, whereas lateral penumbra was independent of modulation. Overall, the comparison between the results of TPS with that of measurements indicates a good agreement for lateral penumbra, with TPS predicting higher values compared to

  14. Model of lifetimes of the outer radiation belt electrons in a realistic magnetic field using realistic chorus wave parameters

    NASA Astrophysics Data System (ADS)

    Orlova, Ksenia; Shprits, Yuri

    2014-02-01

    The outer radiation belt electrons in the inner magnetosphere show high variability during the geomagnetically disturbed conditions. Quasi-linear diffusion theory provides both a framework for global prediction of particle loss at different energies and an understanding of the dynamics of different particle populations. It has been recently shown that the pitch angle scattering of electrons due to wave-particle interaction with chorus waves modeled in a realistic magnetic field may be significantly different from those estimated in a dipole model. In this work, we present the lifetimes of 1 keV-2 MeV electrons computed in the Tsyganenko 89 magnetic field model for the night, dawn, prenoon, and postnoon magnetic local time (MLT) sectors for different levels of geomagnetic activity and distances. The lifetimes in the realistic field are also compared to those computed in the dipole model. We develop a realistic chorus lower band and upper band wave models for each MLT sector using the recent statistical studies of wave amplitude, wave normal angle, and wave spectral density distributions as functions of magnetic latitude, distance, and Kp index. The increase of plasma trough density with increasing latitude is also included. The obtained in the Tsyganenko 89 field electron lifetimes are parameterized and can be used in 2-D/3-D/4-D convection and particle tracing codes.

  15. Spectral tunability of realistic plasmonic nanoantennas

    SciTech Connect

    Portela, Alejandro; Matsui, Hiroaki; Tabata, Hitoshi; Yano, Takaaki; Hayashi, Tomohiro; Hara, Masahiko; Santschi, Christian; Martin, Olivier J. F.

    2014-09-01

    Single nanoantenna spectroscopy was carried out on realistic dipole nanoantennas with various arm lengths and gap sizes fabricated by electron-beam lithography. A significant difference in resonance wavelength between realistic and ideal nanoantennas was found by comparing their spectral response. Consequently, the spectral tunability (96 nm) of the structures was significantly lower than that of simulated ideal nanoantennas. These observations, attributed to the nanofabrication process, are related to imperfections in the geometry, added metal adhesion layer, and shape modifications, which are analyzed in this work. Our results provide important information for the design of dipole nanoantennas clarifying the role of the structural modifications on the resonance spectra, as supported by calculations.

  16. Realistic molecular model of kerogen's nanostructure

    NASA Astrophysics Data System (ADS)

    Bousige, Colin; Ghimbeu, Camélia Matei; Vix-Guterl, Cathie; Pomerantz, Andrew E.; Suleimenova, Assiya; Vaughan, Gavin; Garbarino, Gaston; Feygenson, Mikhail; Wildgruber, Christoph; Ulm, Franz-Josef; Pellenq, Roland J.-M.; Coasne, Benoit

    2016-05-01

    Despite kerogen's importance as the organic backbone for hydrocarbon production from source rocks such as gas shale, the interplay between kerogen's chemistry, morphology and mechanics remains unexplored. As the environmental impact of shale gas rises, identifying functional relations between its geochemical, transport, elastic and fracture properties from realistic molecular models of kerogens becomes all the more important. Here, by using a hybrid experimental-simulation method, we propose a panel of realistic molecular models of mature and immature kerogens that provide a detailed picture of kerogen's nanostructure without considering the presence of clays and other minerals in shales. We probe the models' strengths and limitations, and show that they predict essential features amenable to experimental validation, including pore distribution, vibrational density of states and stiffness. We also show that kerogen's maturation, which manifests itself as an increase in the sp2/sp3 hybridization ratio, entails a crossover from plastic-to-brittle rupture mechanisms.

  17. The Challenge of Realistic TPV System Modeling

    NASA Astrophysics Data System (ADS)

    Aschaber, J.; Hebling, C.; Luther, J.

    2003-01-01

    Realistic modeling of a TPV system is a very demanding task. For a rough estimation of system limits many of assumptions simplify the complexity of a thermophotovoltaic converter. It's obvious that real systems can not be described by this way. An alternative approach that can deal with all these complexities like arbitrary geometries, participating media, temperature distributions etc. is the Monte Carlo method (MCM). This statistical method simulates radiative energy transfer by tracking the histories of a number of photons beginning with the emission by a radiating surface and ending with absorption on a surface or in a medium. All interactions in this way are considered. The disadvantage of large computation time compared to other methods is not longer a weakness with the speed of todays computers. This article points out different ways for realistic TPV system simulation focusing on statistical methods.

  18. Realistic molecular model of kerogen's nanostructure.

    PubMed

    Bousige, Colin; Ghimbeu, Camélia Matei; Vix-Guterl, Cathie; Pomerantz, Andrew E; Suleimenova, Assiya; Vaughan, Gavin; Garbarino, Gaston; Feygenson, Mikhail; Wildgruber, Christoph; Ulm, Franz-Josef; Pellenq, Roland J-M; Coasne, Benoit

    2016-05-01

    Despite kerogen's importance as the organic backbone for hydrocarbon production from source rocks such as gas shale, the interplay between kerogen's chemistry, morphology and mechanics remains unexplored. As the environmental impact of shale gas rises, identifying functional relations between its geochemical, transport, elastic and fracture properties from realistic molecular models of kerogens becomes all the more important. Here, by using a hybrid experimental-simulation method, we propose a panel of realistic molecular models of mature and immature kerogens that provide a detailed picture of kerogen's nanostructure without considering the presence of clays and other minerals in shales. We probe the models' strengths and limitations, and show that they predict essential features amenable to experimental validation, including pore distribution, vibrational density of states and stiffness. We also show that kerogen's maturation, which manifests itself as an increase in the sp(2)/sp(3) hybridization ratio, entails a crossover from plastic-to-brittle rupture mechanisms. PMID:26828313

  19. PLATO Simulator: Realistic simulations of expected observations

    NASA Astrophysics Data System (ADS)

    Marcos-Arenal, P.; Zima, W.; De Ridder, J.; Aerts, C.; Huygen, R.; Samadi, R.; Green, J.; Piotto, G.; Salmon, S.; Catala, C.; Rauer, H.

    2015-06-01

    PLATO Simulator is an end-to-end simulation software tool designed for the performance of realistic simulations of the expected observations of the PLATO mission but easily adaptable to similar types of missions. It models and simulates photometric time-series of CCD images by including models of the CCD and its electronics, the telescope optics, the stellar field, the jitter movements of the spacecraft, and all important natural noise sources.

  20. Dynamical Symmetries Reflected in Realistic Interactions

    SciTech Connect

    Sviratcheva, K.D.; Draayer, J.P.; Vary, J.P.; /Iowa State U. /LLNL, Livermore /SLAC

    2007-04-06

    Realistic nucleon-nucleon (NN) interactions, derived within the framework of meson theory or more recently in terms of chiral effective field theory, yield new possibilities for achieving a unified microscopic description of atomic nuclei. Based on spectral distribution methods, a comparison of these interactions to a most general Sp(4) dynamically symmetric interaction, which previously we found to reproduce well that part of the interaction that is responsible for shaping pairing-governed isobaric analog 0{sup +} states, can determine the extent to which this significantly simpler model Hamiltonian can be used to obtain an approximate, yet very good description of low-lying nuclear structure. And furthermore, one can apply this model in situations that would otherwise be prohibitive because of the size of the model space. In addition, we introduce a Sp(4) symmetry breaking term by including the quadrupole-quadrupole interaction in the analysis and examining the capacity of this extended model interaction to imitate realistic interactions. This provides a further step towards gaining a better understanding of the underlying foundation of realistic interactions and their ability to reproduce striking features of nuclei such as strong pairing correlations or collective rotational motion.

  1. 43 CFR 418.11 - Valid headgate deliveries.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Valid headgate deliveries. 418.11 Section... Conditions of Water Delivery § 418.11 Valid headgate deliveries. The valid water deliveries at the headgate... accordance with §§ 418.8 and 418.10. The District will regularly monitor all water deliveries and report...

  2. A realistic evaluation: the case of protocol-based care

    PubMed Central

    2010-01-01

    Background 'Protocol based care' was envisioned by policy makers as a mechanism for delivering on the service improvement agenda in England. Realistic evaluation is an increasingly popular approach, but few published examples exist, particularly in implementation research. To fill this gap, within this paper we describe the application of a realistic evaluation approach to the study of protocol-based care, whilst sharing findings of relevance about standardising care through the use of protocols, guidelines, and pathways. Methods Situated between positivism and relativism, realistic evaluation is concerned with the identification of underlying causal mechanisms, how they work, and under what conditions. Fundamentally it focuses attention on finding out what works, for whom, how, and in what circumstances. Results In this research, we were interested in understanding the relationships between the type and nature of particular approaches to protocol-based care (mechanisms), within different clinical settings (context), and what impacts this resulted in (outcomes). An evidence review using the principles of realist synthesis resulted in a number of propositions, i.e., context, mechanism, and outcome threads (CMOs). These propositions were then 'tested' through multiple case studies, using multiple methods including non-participant observation, interviews, and document analysis through an iterative analysis process. The initial propositions (conjectured CMOs) only partially corresponded to the findings that emerged during analysis. From the iterative analysis process of scrutinising mechanisms, context, and outcomes we were able to draw out some theoretically generalisable features about what works, for whom, how, and what circumstances in relation to the use of standardised care approaches (refined CMOs). Conclusions As one of the first studies to apply realistic evaluation in implementation research, it was a good fit, particularly given the growing emphasis on

  3. Realistic and efficient 2D crack simulation

    NASA Astrophysics Data System (ADS)

    Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek

    2010-04-01

    Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.

  4. Anderson localization for chemically realistic systems

    NASA Astrophysics Data System (ADS)

    Terletska, Hanna

    2015-03-01

    Disorder which is ubiquitous for most materials can strongly effect their properties. It may change their electronic structures or even cause their localization, known as Anderson localization. Although, substantial progress has been achieved in the description of the Anderson localization, a proper mean-field theory of this phenomenon for more realistic systems remains elusive. Commonly used theoretical methods such as the coherent potential approximation and its cluster extensions fail to describe the Anderson transition, as the average density of states (DOS) employed in such theories is not critical at the transition. However, near the transition, due to the spatial confinement of carriers, the local DOS becomes highly skewed with a log-normal distribution, for which the most probable and the typical values differ noticeably from the average value. Dobrosavljevic et.al., incorporated such ideas in their typical medium theory (TMT), and showed that the typical (not average) DOS is critical at the transition. While the TMT is able to capture the localized states, as a local single site theory it still has several drawbacks. For the disorder Anderson model in three dimension it underestimates the critical disorder strength, and fails to capture the re-entrance behavior of the mobility edge. We have recently developed a cluster extension of the TMT, which addresses these drawbacks by systematically incorporating non-local corrections. This approach converges quickly with cluster size and allows us to incorporate the effect of interactions and realistic electronic structure. As the first steps towards realistic material modeling, we extended our TMDCA formalisms to systems with the off diagonal disorder and multiple bands structures. We also applied our TMDCA scheme to systems with both disorder and interactions and found that correlations effects tend to stabilize the metallic behavior even in two dimensions. This work was supported by DOE SciDAC Grant No. DE-FC02

  5. Adiabatic Hyperspherical Analysis of Realistic Nuclear Potentials

    NASA Astrophysics Data System (ADS)

    Daily, K. M.; Kievsky, Alejandro; Greene, Chris H.

    2015-12-01

    Using the hyperspherical adiabatic method with the realistic nuclear potentials Argonne V14, Argonne V18, and Argonne V18 with the Urbana IX three-body potential, we calculate the adiabatic potentials and the triton bound state energies. We find that a discrete variable representation with the slow variable discretization method along the hyperradial degree of freedom results in energies consistent with the literature. However, using a Laguerre basis results in missing energy, even when extrapolated to an infinite number of basis functions and channels. We do not include the isospin T = 3/2 contribution in our analysis.

  6. Quantum states prepared by realistic entanglement swapping

    SciTech Connect

    Scherer, Artur; Howard, Regina B.; Sanders, Barry C.; Tittel, Wolfgang

    2009-12-15

    Entanglement swapping between photon pairs is a fundamental building block in schemes using quantum relays or quantum repeaters to overcome the range limits of long-distance quantum key distribution. We develop a closed-form solution for the actual quantum states prepared by realistic entanglement swapping, which takes into account experimental deficiencies due to inefficient detectors, detector dark counts, and multiphoton-pair contributions of parametric down-conversion sources. We investigate how the entanglement present in the final state of the remaining modes is affected by the real-world imperfections. To test the predictions of our theory, comparison with previously published experimental entanglement swapping is provided.

  7. Realist model approach to quantum mechanics

    NASA Astrophysics Data System (ADS)

    Hájíček, P.

    2013-06-01

    The paper proves that quantum mechanics is compatible with the constructive realism of modern philosophy of science. The proof is based on the observation that properties of quantum systems that are uniquely determined by their preparations can be assumed objective without the difficulties that are encountered by the same assumption about values of observables. The resulting realist interpretation of quantum mechanics is made rigorous by studying the space of quantum states—the convex set of state operators. Prepared states are classified according to their statistical structure into indecomposable and decomposable instead of pure and mixed. Simple objective properties are defined and showed to form a Boolean lattice.

  8. A realistic renormalizable supersymmetric E₆ model

    SciTech Connect

    Bajc, Borut; Susič, Vasja

    2014-01-01

    A complete realistic model based on the supersymmetric version of E₆ is presented. It consists of three copies of matter 27, and a Higgs sector made of 2×(27+27⁻)+351´+351´⁻ representations. An analytic solution to the equations of motion is found which spontaneously breaks the gauge group into the Standard Model. The light fermion mass matrices are written down explicitly as non-linear functions of three Yukawa matrices. This contribution is based on Ref. [1].

  9. Realistic Ground Motion Scenarios: Methodological Approach

    SciTech Connect

    Nunziata, C.; Peresan, A.; Romanelli, F.; Vaccari, F.; Zuccolo, E.; Panza, G. F.

    2008-07-08

    The definition of realistic seismic input can be obtained from the computation of a wide set of time histories, corresponding to possible seismotectonic scenarios. The propagation of the waves in the bedrock from the source to the local laterally varying structure is computed with the modal summation technique, while in the laterally heterogeneous structure the finite difference method is used. The definition of shear wave velocities within the soil cover is obtained from the non-linear inversion of the dispersion curve of group velocities of Rayleigh waves, artificially or naturally generated. Information about the possible focal mechanisms of the sources can be obtained from historical seismicity, based on earthquake catalogues and inversion of isoseismal maps. In addition, morphostructural zonation and pattern recognition of seismogenic nodes is useful to identify areas prone to strong earthquakes, based on the combined analysis of topographic, tectonic, geological maps and satellite photos. We show that the quantitative knowledge of regional geological structures and the computation of realistic ground motion can be a powerful tool for a preventive definition of the seismic hazard in Italy. Then, the formulation of reliable building codes, based on the evaluation of the main potential earthquakes, will have a great impact on the effective reduction of the seismic vulnerability of Italian urban areas, validating or improving the national building code.

  10. Realistic magnetohydrodynamical simulation of solar local supergranulation

    NASA Astrophysics Data System (ADS)

    Ustyugov, Sergey D.

    2010-12-01

    Three-dimensional numerical simulations of solar surface magnetoconvection using realistic model physics are conducted. The thermal structure of convective motions into the upper radiative layers of the photosphere, the main scales of convective cells and the penetration depths of convection are investigated. We take part of the solar photosphere with a size of 60×60 Mm2 in the horizontal direction and of depth 20 Mm from the level of the visible solar surface. We use a realistic initial model of the sun and apply the equation of state and opacities of stellar matter. The equations of fully compressible radiation magnetohydrodynamics (MHD) with dynamical viscosity and gravity are solved. We apply (i) the conservative total variation diminishing (TVD) difference scheme for MHD, (ii) the diffusion approximation for radiative transfer and (iii) dynamical viscosity from subgrid-scale modeling. In simulation, we take a uniform two-dimensional grid in the horizontal plane and a nonuniform grid in the vertical direction with the number of cells being 600×600×204. We use 512 processors with distributed memory multiprocessors on the supercomputer MVS-100k at the Joint Computational Centre of the Russian Academy of Sciences.

  11. The realist interpretation of the atmosphere

    NASA Astrophysics Data System (ADS)

    Anduaga, Aitor

    The discovery of a clearly stratified structure of layers in the upper atmosphere has been--and still is--invoked too often as the great paradigm of atmospheric sciences in the 20th century. Behind this vision, an emphasis--or better, an overstatement--on the reality of the concept of layer lies. One of the few historians of physics who have not ignored this phenomenon of reification, C. Stewart Gillmor, attributed it to--somewhat ambiguous-- cultural (or perhaps, more generally, contextual) factors, though he never specified their nature. In this essay, I aim to demonstrate that, in the interwar years, most radiophysicists and some atomic physicists, for reasons principally related to extrinsic influences and to a lesser extent to internal developments of their own science, fervidly embraced a realist interpretation of the ionosphere. We will focus on the historical circumstances in which a specific social and commercial environment came to exert a strong influence on upper atmospheric physicists, and in which realism as a product validating the "truth" of certain practices and beliefs arose. This realist commitment I attribute to the mutual reinforcement of atmospheric physics and commercial and imperial interests in long-distance communications.

  12. Realistic Radio Communications in Pilot Simulator Training

    NASA Technical Reports Server (NTRS)

    Burki-Cohen, Judith; Kendra, Andrew J.; Kanki, Barbara G.; Lee, Alfred T.

    2000-01-01

    Simulators used for total training and evaluation of airline pilots must satisfy stringent criteria in order to assure their adequacy for training and checking maneuvers. Air traffic control and company radio communications simulation, however, may still be left to role-play by the already taxed instructor/evaluators in spite of their central importance in every aspect of the flight environment. The underlying premise of this research is that providing a realistic radio communications environment would increase safety by enhancing pilot training and evaluation. This report summarizes the first-year efforts of assessing the requirement and feasibility of simulating radio communications automatically. A review of the training and crew resource/task management literature showed both practical and theoretical support for the need for realistic radio communications simulation. A survey of 29 instructor/evaluators from 14 airlines revealed that radio communications are mainly role-played by the instructor/evaluators. This increases instructor/evaluators' own workload while unrealistically lowering pilot communications load compared to actual operations, with a concomitant loss in training/evaluation effectiveness. A technology review searching for an automated means of providing radio communications to and from aircraft with minimal human effort showed that while promising, the technology is still immature. Further research and the need for establishing a proof-of-concept are also discussed.

  13. Super stereoscopy technique for comfortable and realistic 3D displays.

    PubMed

    Akşit, Kaan; Niaki, Amir Hossein Ghanbari; Ulusoy, Erdem; Urey, Hakan

    2014-12-15

    Two well-known problems of stereoscopic displays are the accommodation-convergence conflict and the lack of natural blur for defocused objects. We present a new technique that we name Super Stereoscopy (SS3D) to provide a convenient solution to these problems. Regular stereoscopic glasses are replaced by SS3D glasses which deliver at least two parallax images per eye through pinholes equipped with light selective filters. The pinholes generate blur-free retinal images so as to enable correct accommodation, while the delivery of multiple parallax images per eye creates an approximate blur effect for defocused objects. Experiments performed with cameras and human viewers indicate that the technique works as desired. In case two, pinholes equipped with color filters per eye are used; the technique can be used on a regular stereoscopic display by only uploading a new content, without requiring any change in display hardware, driver, or frame rate. Apart from some tolerable loss in display brightness and decrease in natural spatial resolution limit of the eye because of pinholes, the technique is quite promising for comfortable and realistic 3D vision, especially enabling the display of close objects that are not possible to display and comfortably view on regular 3DTV and cinema. PMID:25503026

  14. A realist evaluation of the role of communities of practice in changing healthcare practice

    PubMed Central

    2011-01-01

    Background Healthcare organisations seeking to manage knowledge and improve organisational performance are increasingly investing in communities of practice (CoPs). Such investments are being made in the absence of empirical evidence demonstrating the impact of CoPs in improving the delivery of healthcare. A realist evaluation is proposed to address this knowledge gap. Underpinned by the principle that outcomes are determined by the context in which an intervention is implemented, a realist evaluation is well suited to understand the role of CoPs in improving healthcare practice. By applying a realist approach, this study will explore the following questions: What outcomes do CoPs achieve in healthcare? Do these outcomes translate into improved practice in healthcare? What are the contexts and mechanisms by which CoPs improve healthcare? Methods The realist evaluation will be conducted by developing, testing, and refining theories on how, why, and when CoPs improve healthcare practice. When collecting data, context will be defined as the setting in which the CoP operates; mechanisms will be the factors and resources that the community offers to influence a change in behaviour or action; and outcomes will be defined as a change in behaviour or work practice that occurs as a result of accessing resources provided by the CoP. Discussion Realist evaluation is being used increasingly to study social interventions where context plays an important role in determining outcomes. This study further enhances the value of realist evaluations by incorporating a social network analysis component to quantify the structural context associated with CoPs. By identifying key mechanisms and contexts that optimise the effectiveness of CoPs, this study will contribute to creating a framework that will guide future establishment and evaluation of CoPs in healthcare. PMID:21600057

  15. Effect of realistic vegetation variability on seasonal forecasts

    NASA Astrophysics Data System (ADS)

    Catalano, Franco; Alessandri, Andrea; De Felice, Matteo; Doblas-Reyes, Francisco J.

    2014-05-01

    A real predictability hindcast experiment with prescribed Leaf Area Index (LAI) has been performed using the state-of-the-art Earth System Model EC-Earth. LAI input to the climate model has been prescribed using a novel observational dataset based on the third generation GIMMS and MODIS satellite data. The LAI dataset has been pre-processed (monthly averaged, interpolated, gap-filled) to use it in the land surface scheme of EC-Earth (HTESSEL). The vegetation density is modeled by an exponential dependence on LAI, based on the Lambert-Beer formulation. Retrospective hindcasts have been performed with the following model setup: 7 months forecast length, 2 start dates (1st May and 1st November), 10 members, 28 years (1982-2009). Initial conditions were produced at IC3, based on ERA-40/ERA-Interim (atmosphere and land-surface) and NEMOVAR-ORAS4 (ocean and sea-ice) data. Model resolution is T159L62 for the atmosphere and the ORCA1 grid for the ocean. The effect of the realistic LAI prescribed from observation is evaluated with respect to a control experiment where LAI does not vary. Results of the retrospective hindcast experiment demonstrate that a realistic representation of vegetation has a significant effect on evaporation, temperature and precipitation. An improvement of model sensitivity to vegetation variability on the seasonal scale is also evidenced, especially during boreal winter. This may be attributed in particular to the effect of the high vegetation component on the snow cover.

  16. HELIOSEISMOLOGY OF A REALISTIC MAGNETOCONVECTIVE SUNSPOT SIMULATION

    SciTech Connect

    Braun, D. C.; Birch, A. C.; Rempel, M.; Duvall, T. L. Jr. E-mail: aaronb@cora.nwra.com E-mail: Thomas.L.Duvall@nasa.gov

    2012-01-01

    We compare helioseismic travel-time shifts measured from a realistic magnetoconvective sunspot simulation using both helioseismic holography and time-distance helioseismology, and measured from real sunspots observed with the Helioseismic and Magnetic Imager instrument on board the Solar Dynamics Observatory and the Michelson Doppler Imager instrument on board the Solar and Heliospheric Observatory. We find remarkable similarities in the travel-time shifts measured between the methodologies applied and between the simulated and real sunspots. Forward modeling of the travel-time shifts using either Born or ray approximation kernels and the sound-speed perturbations present in the simulation indicates major disagreements with the measured travel-time shifts. These findings do not substantially change with the application of a correction for the reduction of wave amplitudes in the simulated and real sunspots. Overall, our findings demonstrate the need for new methods for inferring the subsurface structure of sunspots through helioseismic inversions.

  17. Helioseismology of a Realistic Magnetoconvective Sunspot Simulation

    NASA Technical Reports Server (NTRS)

    Braun, D. C.; Birch, A. C.; Rempel, M.; Duvall, T. L., Jr.

    2012-01-01

    We compare helioseismic travel-time shifts measured from a realistic magnetoconvective sunspot simulation using both helioseismic holography and time-distance helioseismology, and measured from real sunspots observed with the Helioseismic and Magnetic Imager instrument on board the Solar Dynamics Observatory and the Michelson Doppler Imager instrument on board the Solar and Heliospheric Observatory. We find remarkable similarities in the travel-time shifts measured between the methodologies applied and between the simulated and real sunspots. Forward modeling of the travel-time shifts using either Born or ray approximation kernels and the sound-speed perturbations present in the simulation indicates major disagreements with the measured travel-time shifts. These findings do not substantially change with the application of a correction for the reduction of wave amplitudes in the simulated and real sunspots. Overall, our findings demonstrate the need for new methods for inferring the subsurface structure of sunspots through helioseismic inversions.

  18. Field line resonances in a realistic magnetosphere

    SciTech Connect

    Mukherjee, G.K.; Rajaram, R. )

    1989-04-01

    An internally consistent theoretical framework is developed to study the field line oscillations in the realistic magnetospheric magnetic field using the Mead and Fairfield (1975) model. The nondipolar contributions are numerically computed for the fundamental period of the modes that would reduce to the localized toroidal and poloidal modes described by Cummings et al. (1969) in the dipole limit. It is shown that the nondipolar contributions are not significant at the geostationary orbit but become large further out in the magnetosphere. The nondipolar contributions are very different for the two modes. The situation becomes very much more complicated in the dawn/dusk region where a continuous range of periods exist depending on the orientation of the field line oscillation.

  19. Realistic page-turning of electronic books

    NASA Astrophysics Data System (ADS)

    Fan, Chaoran; Li, Haisheng; Bai, Yannan

    2014-01-01

    The booming electronic books (e-books), as an extension to the paper book, are popular with readers. Recently, many efforts are put into the realistic page-turning simulation o f e-book to improve its reading experience. This paper presents a new 3D page-turning simulation approach, which employs piecewise time-dependent cylindrical surfaces to describe the turning page and constructs smooth transition method between time-dependent cylinders. The page-turning animation is produced by sequentially mapping the turning page into the cylinders with different radii and positions. Compared to the previous approaches, our method is able to imitate various effects efficiently and obtains more natural animation of turning page.

  20. Realistic limits for subpixel movement detection.

    PubMed

    Mas, David; Perez, Jorge; Ferrer, Belen; Espinosa, Julian

    2016-07-01

    Object tracking with subpixel accuracy is of fundamental importance in many fields since it provides optimal performance at relatively low cost. Although there are many theoretical proposals that lead to resolution increments of several orders of magnitude, in practice this resolution is limited by the imaging systems. In this paper we propose and demonstrate through simple numerical models a realistic limit for subpixel accuracy. The final result is that maximum achievable resolution enhancement is connected with the dynamic range of the image, i.e., the detection limit is 1/2(nr.bits). The results here presented may aid in proper design of superresolution experiments in microscopy, surveillance, defense, and other fields. PMID:27409179

  1. Two Realistic Beagle Models for Dose Assessment.

    PubMed

    Stabin, Michael G; Kost, Susan D; Segars, William P; Guilmette, Raymond A

    2015-09-01

    Previously, the authors developed a series of eight realistic digital mouse and rat whole body phantoms based on NURBS technology to facilitate internal and external dose calculations in various species of rodents. In this paper, two body phantoms of adult beagles are described based on voxel images converted to NURBS models. Specific absorbed fractions for activity in 24 organs are presented in these models. CT images were acquired of an adult male and female beagle. The images were segmented, and the organs and structures were modeled using NURBS surfaces and polygon meshes. Each model was voxelized at a resolution of 0.75 × 0.75 × 2 mm. The voxel versions were implemented in GEANT4 radiation transport codes to calculate specific absorbed fractions (SAFs) using internal photon and electron sources. Photon and electron SAFs were then calculated for relevant organs in both models. The SAFs for photons and electrons were compatible with results observed by others. Absorbed fractions for electrons for organ self-irradiation were significantly less than 1.0 at energies above 0.5 MeV, as expected for many of these small-sized organs, and measurable cross irradiation was observed for many organ pairs for high-energy electrons (as would be emitted by nuclides like 32P, 90Y, or 188Re). The SAFs were used with standardized decay data to develop dose factors (DFs) for radiation dose calculations using the RADAR Method. These two new realistic models of male and female beagle dogs will be useful in radiation dosimetry calculations for external or internal simulated sources. PMID:26222214

  2. Realistic texture in simulated thermal infrared imagery

    NASA Astrophysics Data System (ADS)

    Ward, Jason T.

    Creating a visually-realistic yet radiometrically-accurate simulation of thermal infrared (TIR) imagery is a challenge that has plagued members of industry and academia alike. The goal of imagery simulation is to provide a practical alternative to the often staggering effort required to collect actual data. Previous attempts at simulating TIR imagery have suffered from a lack of texture---the simulated scenes generally failed to reproduce the natural variability seen in actual TIR images. Realistic synthetic TIR imagery requires modeling sources of variability including surface effects such as solar insolation and convective heat exchange as well as sub-surface effects such as density and water content. This research effort utilized the Digital Imaging and Remote Sensing Image Generation (DIRSIG) model, developed at the Rochester Institute of Technology, to investigate how these additional sources of variability could be modeled to correctly and accurately provide simulated TIR imagery. Actual thermal data were collected, analyzed, and exploited to determine the underlying thermodynamic phenomena and ascertain how these phenomena are best modeled. The underlying task was to determine how to apply texture in the thermal region to attain radiometrically-correct, visually-appealing simulated imagery. Three natural desert scenes were used to test the methodologies that were developed for estimating per-pixel thermal parameters which could then be used for TIR image simulation by DIRSIG. Additional metrics were devised and applied to the synthetic images to further quantify the success of this research. The resulting imagery demonstrated that these new methodologies for modeling TIR phenomena and the utilization of an improved DIRSIG tool improved the root mean-squared error (RMSE) of our synthetic TIR imagery by up to 88%.

  3. More Realistic Face Model Surface Improves Relevance of Pediatric In-Vitro Aerosol Studies

    PubMed Central

    Amirav, Israel; Halamish, Asaf; Gorenberg, Miguel; Omar, Hamza; Newhouse, Michael T.

    2015-01-01

    Background Various hard face models are commonly used to evaluate the efficiency of aerosol face masks. Softer more realistic “face” surface materials, like skin, deform upon mask application and should provide more relevant in-vitro tests. Studies that simultaneously take into consideration many of the factors characteristic of the in vivo face are lacking. These include airways, various application forces, comparison of various devices, comparison with a hard-surface model and use of a more representative model face based on large numbers of actual faces. Aim To compare mask to “face” seal and aerosol delivery of two pediatric masks using a soft vs. a hard, appropriately representative, pediatric face model under various applied forces. Methods Two identical face models and upper airways replicas were constructed, the only difference being the suppleness and compressibility of the surface layer of the “face.” Integrity of the seal and aerosol delivery of two different masks [AeroChamber (AC) and SootherMask (SM)] were compared using a breath simulator, filter collection and realistic applied forces. Results The soft “face” significantly increased the delivery efficiency and the sealing characteristics of both masks. Aerosol delivery with the soft “face” was significantly greater for the SM compared to the AC (p< 0.01). No statistically significant difference between the two masks was observed with the hard “face.” Conclusions The material and pliability of the model “face” surface has a significant influence on both the seal and delivery efficiency of face masks. This finding should be taken into account during in-vitro aerosol studies. PMID:26090661

  4. Controlled iontophoretic transport of huperzine A across skin in vitro and in vivo: effect of delivery conditions and comparison of pharmacokinetic models.

    PubMed

    Kalaria, Dhaval R; Patel, Pratikkumar; Merino, Virginia; Patravale, Vandana B; Kalia, Yogeshvar N

    2013-11-01

    The aim of this study was to investigate constant current anodal iontophoresis of Huperzine A (HupA) in vitro and in vivo and hence to evaluate the feasibility of using electrically assisted delivery to administer therapeutic amounts of the drug across the skin for the treatment of Alzheimer's disease. Preliminary experiments were performed using porcine and human skin in vitro. Stability studies demonstrated that HupA was not degraded upon exposure to epidermis or dermis for 12 h and that it was also stable in the presence of an electric current (0.5 mA · cm(-2)). Passive permeation of HupA (2 mM) was minimal (1.1 ± 0.1 μg · cm(-2)); iontophoresis at 0.15, 0.3, and 0.5 mA · cm(-2) produced 106-, 134-, and 184-fold increases in its transport across the skin. Surprisingly, despite the use of a salt bridge to isolate the formulation compartment from the anodal chamber, which contained 133 mM NaCl, iontophoresis of HupA was shown to increase linearly with its concentration (1, 2, and 4 mM in 25 mM MES, pH 5.0) (r(2) = 0.99). This was attributed to the low ratio of drug to Cl¯ (in the skin and in the receiver compartment) which competed strongly to carry current, its depletion, and to possible competition from the zwitterionic MES. Co-iontophoresis of acetaminophen confirmed that electromigration was the dominant electrotransport mechanism. Total delivery across human and porcine skin was found to be statistically equivalent (243.2 ± 33.1 and 235.6 ± 13.7 μg · cm(-2), respectively). Although the transport efficiency was ∼ 1%, the iontophoretic delivery efficiency (i.e., the fraction of the drug load delivered) was extremely high, in the range of 46-81% depending on the current density. Cumulative permeation of HupA from a Carbopol gel formulation after iontophoresis for 6 h at 0.5 mA · cm(-2) was less than that from solution (135.3 ± 25.2 and 202.9 ± 5.2 μg · cm(-2), respectively) but sufficient for therapeutic delivery. Pharmacokinetic parameters were

  5. A Study of Fe3O4 Magnetic Nanoparticle RF Heating in Gellan Gum Polymer Under Various Experimental Conditions for Potential Application in Drug Delivery

    NASA Astrophysics Data System (ADS)

    Marcus, Gabriel E.

    Magnetic nanoparticles (MNPs) have found use in a wide variety of biomedical applications including hyperthermia, imaging and drug delivery. Certain physical properties, such as the ability to generate heat in response to an alternating magnetic field, make these structures ideal for such purposes. This study's objective was to elucidate the mechanisms primarily responsible for RF MNP heating and determine how such processes affect polymer solutions that might be useful in drug delivery. 15-20 nm magnetite (Fe3O4) nanoparticles at 0.2% and 0.5% concentrations were heated with RF fields of different strengths (200 Oe, 400 Oe and 600 Oe) in water and in 0.5% gellan gum solution. Mixing and fan cooling were used in an attempt to improve accuracy of data collection. Specific absorption rate (SAR) values were determined experimentally for each combination of solvent, concentration and field strength. Theoretical calculation of SAR was performed using a model based on linear response theory. Mixing yielded greater precision in experimental determination of SAR while the effects of cooling on this parameter were negligible. Solutions with gellan gum displayed smoother heating over time but no significant changes in SAR values. This was attributed to low polymer concentration and lack of structural phase transition. The LRT model was found to be adequate for calculating SAR at low polymer concentration and was useful in identifying Neel relaxation as the dominant heating process. Heating trials with MNPs in 2% agar confirmed Neel relaxation to be primarily responsible for heat generation in the particles studied.

  6. Realistic electrostatic potentials in a neutron star crust

    NASA Astrophysics Data System (ADS)

    Ebel, Claudio; Mishustin, Igor; Greiner, Walter

    2015-10-01

    We study the electrostatic properties of inhomogeneous nuclear matter which can be formed in the crusts of neutron stars or in supernova explosions. Such matter is represented by Wigner-Seitz cells of different geometries (spherical, cylindrical, cartesian), which contain nuclei, free neutrons and electrons under the conditions of electrical neutrality. Using the Thomas-Fermi approximation, we have solved the Poisson equation for the electrostatic potential and calculated the corresponding electron density distributions in individual cells. The calculations are done for different shapes and sizes of the cells and different average baryon densities. The electron-to-baryon fraction was fixed at 0.3. Using realistic electron distributions leads to a significant reduction in electrostatic energy and electron chemical potential.

  7. Bosonic structure of realistic SO(10) supersymmetric cosmic strings

    NASA Astrophysics Data System (ADS)

    Allys, Erwan

    2016-05-01

    We study the bosonic structure of F -term Nambu-Goto cosmic strings forming in a realistic SO(10) implementation, assuming standard hybrid inflation. We describe the supersymmetric grand unified theory, and its spontaneous symmetry breaking scheme in parallel with the inflationary process. We also write the explicit tensor formulation of its scalar sector, focusing on the subrepresentations singlet under the standard model, which is sufficient to describe the string structure. We then introduce an ansatz for Abelian cosmic strings, discussing in details the hypothesis, and write down the field equations and boundary conditions. Finally, after doing a perturbative study of the model, we present and discuss the results obtained with numerical solutions of the string structure.

  8. Differentiability of correlations in realistic quantum mechanics

    SciTech Connect

    Cabrera, Alejandro; Faria, Edson de; Pujals, Enrique; Tresser, Charles

    2015-09-15

    We prove a version of Bell’s theorem in which the locality assumption is weakened. We start by assuming theoretical quantum mechanics and weak forms of relativistic causality and of realism (essentially the fact that observable values are well defined independently of whether or not they are measured). Under these hypotheses, we show that only one of the correlation functions that can be formulated in the framework of the usual Bell theorem is unknown. We prove that this unknown function must be differentiable at certain angular configuration points that include the origin. We also prove that, if this correlation is assumed to be twice differentiable at the origin, then we arrive at a version of Bell’s theorem. On the one hand, we are showing that any realistic theory of quantum mechanics which incorporates the kinematic aspects of relativity must lead to this type of rough correlation function that is once but not twice differentiable. On the other hand, this study brings us a single degree of differentiability away from a relativistic von Neumann no hidden variables theorem.

  9. Differentiability of correlations in realistic quantum mechanics

    NASA Astrophysics Data System (ADS)

    Cabrera, Alejandro; de Faria, Edson; Pujals, Enrique; Tresser, Charles

    2015-09-01

    We prove a version of Bell's theorem in which the locality assumption is weakened. We start by assuming theoretical quantum mechanics and weak forms of relativistic causality and of realism (essentially the fact that observable values are well defined independently of whether or not they are measured). Under these hypotheses, we show that only one of the correlation functions that can be formulated in the framework of the usual Bell theorem is unknown. We prove that this unknown function must be differentiable at certain angular configuration points that include the origin. We also prove that, if this correlation is assumed to be twice differentiable at the origin, then we arrive at a version of Bell's theorem. On the one hand, we are showing that any realistic theory of quantum mechanics which incorporates the kinematic aspects of relativity must lead to this type of rough correlation function that is once but not twice differentiable. On the other hand, this study brings us a single degree of differentiability away from a relativistic von Neumann no hidden variables theorem.

  10. Real-time realistic skin translucency.

    PubMed

    Jimenez, Jorge; Whelan, David; Sundstedt, Veronica; Gutierrez, Diego

    2010-01-01

    Diffusion theory allows the production of realistic skin renderings. The dipole and multipole models allow for solving challenging diffusion-theory equations efficiently. By using texture-space diffusion, a Gaussian-based approximation, and programmable graphics hardware, developers can create real-time, photorealistic skin renderings. Performing this diffusion in screen space offers advantages that make diffusion approximation practical in scenarios such as games, where having the best possible performance is crucial. However, unlike the texture-space counterpart, the screen-space approach can't simulate transmittance of light through thin geometry; it yields unrealistic results in those cases. A new transmittance algorithm turns the screen-space approach into an efficient global solution, capable of simulating both reflectance and transmittance of light through a multilayered skin model. The transmittance calculations are derived from physical equations, which are implemented through simple texture access. The method performs in real time, requiring no additional memory usage and only minimal additional processing power and memory bandwidth. Despite its simplicity, this practical model manages to reproduce the look of images rendered with other techniques (both offline and real time) such as photon mapping or diffusion approximation. PMID:20650726

  11. Fast sawtooth reconnection at realistic Lundquist numbers

    NASA Astrophysics Data System (ADS)

    Günter, S.; Yu, Q.; Lackner, K.; Bhattacharjee, A.; Huang, Y.-M.

    2015-01-01

    Magnetic reconnection, a ubiquitous phenomenon in astrophysics, space science and magnetic confinement research, frequently proceeds much faster than predicted by simple resistive MHD theory. Acceleration can result from the break-up of the thin Sweet-Parker current sheet into plasmoids, or from two-fluid effects decoupling mass and magnetic flux transport over the ion inertial length {{v}A}/{ωci} or the drift scale \\sqrt{{{T}e}/{{m}i}}/{ωci}, depending on the absence or presence of a strong magnetic guide field. We describe new results on the modelling of sawtooth reconnection in a simple tokamak geometry (circular cylindrical equilibrium) pushed to realistic Lundquist numbers for present day tokamaks. For the resistive MHD case, the onset criteria and the influence of plasmoids on the reconnection process agree well with earlier results found in the case of vanishing magnetic guide fields. While plasmoids are also observed in two-fluid calculations, they do not dominate the reconnection process for the range of plasma parameters considered in this study. In the two-fluid case they form as a transient phenomenon only. The reconnection times become weakly dependent on the S-value and for the most complete model—including two-fluid effects and equilibrium temperature and density gradients—agree well with those experimentally found on ASDEX Upgrade ≤ft(≤slant 100 μ s\\right).

  12. Determination of Realistic Fire Scenarios in Spacecraft

    NASA Technical Reports Server (NTRS)

    Dietrich, Daniel L.; Ruff, Gary A.; Urban, David

    2013-01-01

    This paper expands on previous work that examined how large a fire a crew member could successfully survive and extinguish in the confines of a spacecraft. The hazards to the crew and equipment during an accidental fire include excessive pressure rise resulting in a catastrophic rupture of the vehicle skin, excessive temperatures that burn or incapacitate the crew (due to hyperthermia), carbon dioxide build-up or accumulation of other combustion products (e.g. carbon monoxide). The previous work introduced a simplified model that treated the fire primarily as a source of heat and combustion products and sink for oxygen prescribed (input to the model) based on terrestrial standards. The model further treated the spacecraft as a closed system with no capability to vent to the vacuum of space. The model in the present work extends this analysis to more realistically treat the pressure relief system(s) of the spacecraft, include more combustion products (e.g. HF) in the analysis and attempt to predict the fire spread and limiting fire size (based on knowledge of terrestrial fires and the known characteristics of microgravity fires) rather than prescribe them in the analysis. Including the characteristics of vehicle pressure relief systems has a dramatic mitigating effect by eliminating vehicle overpressure for all but very large fires and reducing average gas-phase temperatures.

  13. Realistic calculation of the hep astrophysical factor

    SciTech Connect

    L.E. Marcucci; R. Schiavilla; M. Viviani; A. Kievsky; S. Rosati

    2000-03-01

    The astrophysical factor for the proton weak capture on {sup 3}He is calculated with correlated-hyperspherical-harmonics bound and continuum wave functions corresponding to a realistic Hamiltonian consisting of the Argonne {nu}{sub 18} two-nucleon and Urbana-IX three-nucleon interactions. The nuclear weak charge and current operators have vector and axial-vector components, that include one- and many-body terms. All possible multipole transitions connecting any of the p{sup 3}He S- and P-wave channels to the {sup 4}He bound state are considered. The S-factor at a p{sup 3}He center-of-mass energy of 10 keV, close to the Gamow-peak energy, is predicted to be 10.1 x 10{sup {minus}20} keV b, a factor of five larger than the standard-solar-model value. The P-wave transitions are found to be important, contributing about 40 % of the calculated S-factor.

  14. Comparing Realistic Subthalamic Nucleus Neuron Models

    NASA Astrophysics Data System (ADS)

    Njap, Felix; Claussen, Jens C.; Moser, Andreas; Hofmann, Ulrich G.

    2011-06-01

    The mechanism of action of clinically effective electrical high frequency stimulation is still under debate. However, recent evidence points at the specific activation of GABA-ergic ion channels. Using a computational approach, we analyze temporal properties of the spike trains emitted by biologically realistic neurons of the subthalamic nucleus (STN) as a function of GABA-ergic synaptic input conductances. Our contribution is based on a model proposed by Rubin and Terman and exhibits a wide variety of different firing patterns, silent, low spiking, moderate spiking and intense spiking activity. We observed that most of the cells in our network turn to silent mode when we increase the GABAA input conductance above the threshold of 3.75 mS/cm2. On the other hand, insignificant changes in firing activity are observed when the input conductance is low or close to zero. We thus reproduce Rubin's model with vanishing synaptic conductances. To quantitatively compare spike trains from the original model with the modified model at different conductance levels, we apply four different (dis)similarity measures between them. We observe that Mahalanobis distance, Victor-Purpura metric, and Interspike Interval distribution are sensitive to different firing regimes, whereas Mutual Information seems undiscriminative for these functional changes.

  15. Modeling and Control of Aggregated Air Conditioning Loads Under Realistic Conditions

    SciTech Connect

    Chang, Chin-Yao; Zhang, Wei; Lian, Jianming; Kalsi, Karanjit

    2013-02-24

    Demand-side control is playing an increasingly important role in smart grid control strategies. Modeling the dynamical behavior of a large population of appliances is especially important to evaluate the effectiveness of various load control strategies. In this paper, a high accuracy aggregated model is first developed for a population of HVAC units. The model efficiently includes statistical information of the population, systematically deals with heterogeneity, and accounts for a second-order effect necessary to accurately capture the transient dynamics in the collective response. Furthermore, the model takes into account the lockout effect of the compressor in order to represent the dynamics of the system under control more accurately. Then, a novel closed loop load control strategy is designed to track a desired demand curve and to ensure a stable and smooth response.

  16. Generation of a conditionally self-eliminating HAC gene delivery vector through incorporation of a tTAVP64 expression cassette

    PubMed Central

    Kononenko, Artem V.; Lee, Nicholas C.O.; Liskovykh, Mikhail; Masumoto, Hiroshi; Earnshaw, William C.; Larionov, Vladimir; Kouprina, Natalay

    2015-01-01

    Human artificial chromosome (HAC)-based vectors represent an alternative technology for gene delivery and expression with a potential to overcome the problems caused by virus-based vectors. The recently developed alphoidtetO-HAC has an advantage over other HAC vectors because it can be easily eliminated from cells by inactivation of the HAC kinetochore via binding of chromatin modifiers, tTA or tTS, to its centromeric tetO sequences. This provides a unique control for phenotypes induced by genes loaded into the HAC. The alphoidtetO-HAC elimination is highly efficient when a high level of chromatin modifiers as tetR fusion proteins is achieved following transfection of cells by a retrovirus vector. However, such vectors are potentially mutagenic and might want to be avoided under some circumstances. Here, we describe a novel system that allows verification of phenotypic changes attributed to expression of genes from the HAC without a transfection step. We demonstrated that a single copy of tTAVP64 carrying four tandem repeats of the VP16 domain constitutively expressed from the HAC is capable to generate chromatin changes in the HAC kinetochore that are not compatible with its function. To adopt the alphoidtetO-HAC for routine gene function studies, we constructed a new TAR-BRV- tTAVP64 cloning vector that allows a selective isolation of a gene of interest from genomic DNA in yeast followed by its direct transfer to bacterial cells and subsequent loading into the loxP site of the alphoidtetO-HAC in hamster CHO cells from where the HAC may be MMCT-transferred to the recipient human cells. PMID:25712097

  17. A realistic molecular model of cement hydrates

    PubMed Central

    Pellenq, Roland J.-M.; Kushima, Akihiro; Shahsavari, Rouzbeh; Van Vliet, Krystyn J.; Buehler, Markus J.; Yip, Sidney; Ulm, Franz-Josef

    2009-01-01

    Despite decades of studies of calcium-silicate-hydrate (C-S-H), the structurally complex binder phase of concrete, the interplay between chemical composition and density remains essentially unexplored. Together these characteristics of C-S-H define and modulate the physical and mechanical properties of this “liquid stone” gel phase. With the recent determination of the calcium/silicon (C/S = 1.7) ratio and the density of the C-S-H particle (2.6 g/cm3) by neutron scattering measurements, there is new urgency to the challenge of explaining these essential properties. Here we propose a molecular model of C-S-H based on a bottom-up atomistic simulation approach that considers only the chemical specificity of the system as the overriding constraint. By allowing for short silica chains distributed as monomers, dimers, and pentamers, this C-S-H archetype of a molecular description of interacting CaO, SiO2, and H2O units provides not only realistic values of the C/S ratio and the density computed by grand canonical Monte Carlo simulation of water adsorption at 300 K. The model, with a chemical composition of (CaO)1.65(SiO2)(H2O)1.75, also predicts other essential structural features and fundamental physical properties amenable to experimental validation, which suggest that the C-S-H gel structure includes both glass-like short-range order and crystalline features of the mineral tobermorite. Additionally, we probe the mechanical stiffness, strength, and hydrolytic shear response of our molecular model, as compared to experimentally measured properties of C-S-H. The latter results illustrate the prospect of treating cement on equal footing with metals and ceramics in the current application of mechanism-based models and multiscale simulations to study inelastic deformation and cracking. PMID:19805265

  18. Realistic Detectability of Close Interstellar Comets

    NASA Astrophysics Data System (ADS)

    Cook, Nathaniel V.; Ragozzine, Darin; Granvik, Mikael; Stephens, Denise C.

    2016-07-01

    During the planet formation process, billions of comets are created and ejected into interstellar space. The detection and characterization of such interstellar comets (ICs) (also known as extra-solar planetesimals or extra-solar comets) would give us in situ information about the efficiency and properties of planet formation throughout the galaxy. However, no ICs have ever been detected, despite the fact that their hyperbolic orbits would make them readily identifiable as unrelated to the solar system. Moro-Martín et al. have made a detailed and reasonable estimate of the properties of the IC population. We extend their estimates of detectability with a numerical model that allows us to consider “close” ICs, e.g., those that come within the orbit of Jupiter. We include several constraints on a “detectable” object that allow for realistic estimates of the frequency of detections expected from the Large Synoptic Survey Telescope (LSST) and other surveys. The influence of several of the assumed model parameters on the frequency of detections is explored in detail. Based on the expectation from Moro-Martín et al., we expect that LSST will detect 0.001–10 ICs during its nominal 10 year lifetime, with most of the uncertainty from the unknown number density of small (nuclei of ∼0.1–1 km) ICs. Both asteroid and comet cases are considered, where the latter includes various empirical prescriptions of brightening. Using simulated LSST-like astrometric data, we study the problem of orbit determination for these bodies, finding that LSST could identify their orbits as hyperbolic and determine an ephemeris sufficiently accurate for follow-up in about 4–7 days. We give the hyperbolic orbital parameters of the most detectable ICs. Taking the results into consideration, we give recommendations to future searches for ICs.

  19. Realistic Detectability of Close Interstellar Comets

    NASA Astrophysics Data System (ADS)

    Cook, Nathaniel V.; Ragozzine, Darin; Granvik, Mikael; Stephens, Denise C.

    2016-07-01

    During the planet formation process, billions of comets are created and ejected into interstellar space. The detection and characterization of such interstellar comets (ICs) (also known as extra-solar planetesimals or extra-solar comets) would give us in situ information about the efficiency and properties of planet formation throughout the galaxy. However, no ICs have ever been detected, despite the fact that their hyperbolic orbits would make them readily identifiable as unrelated to the solar system. Moro-Martín et al. have made a detailed and reasonable estimate of the properties of the IC population. We extend their estimates of detectability with a numerical model that allows us to consider “close” ICs, e.g., those that come within the orbit of Jupiter. We include several constraints on a “detectable” object that allow for realistic estimates of the frequency of detections expected from the Large Synoptic Survey Telescope (LSST) and other surveys. The influence of several of the assumed model parameters on the frequency of detections is explored in detail. Based on the expectation from Moro-Martín et al., we expect that LSST will detect 0.001–10 ICs during its nominal 10 year lifetime, with most of the uncertainty from the unknown number density of small (nuclei of ˜0.1–1 km) ICs. Both asteroid and comet cases are considered, where the latter includes various empirical prescriptions of brightening. Using simulated LSST-like astrometric data, we study the problem of orbit determination for these bodies, finding that LSST could identify their orbits as hyperbolic and determine an ephemeris sufficiently accurate for follow-up in about 4–7 days. We give the hyperbolic orbital parameters of the most detectable ICs. Taking the results into consideration, we give recommendations to future searches for ICs.

  20. Towards a realistic population of simulated galaxy groups and clusters

    NASA Astrophysics Data System (ADS)

    Le Brun, Amandine M. C.; McCarthy, Ian G.; Schaye, Joop; Ponman, Trevor J.

    2014-06-01

    We present a new suite of large-volume cosmological hydrodynamical simulations called cosmo-OWLS. They form an extension to the OverWhelmingly Large Simulations (OWLS) project, and have been designed to help improve our understanding of cluster astrophysics and non-linear structure formation, which are now the limiting systematic errors when using clusters as cosmological probes. Starting from identical initial conditions in either the Planck or WMAP7 cosmologies, we systematically vary the most important `sub-grid' physics, including feedback from supernovae and active galactic nuclei (AGN). We compare the properties of the simulated galaxy groups and clusters to a wide range of observational data, such as X-ray luminosity and temperature, gas mass fractions, entropy and density profiles, Sunyaev-Zel'dovich flux, I-band mass-to-light ratio, dominance of the brightest cluster galaxy and central massive black hole (BH) masses, by producing synthetic observations and mimicking observational analysis techniques. These comparisons demonstrate that some AGN feedback models can produce a realistic population of galaxy groups and clusters, broadly reproducing both the median trend and, for the first time, the scatter in physical properties over approximately two decades in mass (1013 M⊙ ≲ M500 ≲ 1015 M⊙) and 1.5 decades in radius (0.05 ≲ r/r500 ≲ 1.5). However, in other models, the AGN feedback is too violent (even though they reproduce the observed BH scaling relations), implying that calibration of the models is required. The production of realistic populations of simulated groups and clusters, as well as models that bracket the observations, opens the door to the creation of synthetic surveys for assisting the astrophysical and cosmological interpretation of cluster surveys, as well as quantifying the impact of selection effects.

  1. Active and realistic passive marijuana exposure tested by three immunoassays and GC/MS in urine

    SciTech Connect

    Mule, S.J.; Lomax, P.; Gross, S.J.

    1988-05-01

    Human urine samples obtained before and after active and passive exposure to marijuana were analyzed by immune kits (Roche, Amersham, and Syva) and gas chromatography/mass spectrometry (GC/MS). Seven of eight subjects were positive for the entire five-day test period with one immune kit. The latter correlated with GC/MS in 98% of the samples. Passive inhalation experiments under conditions likely to reflect realistic exposure resulted consistently in less than 10 ng/mL of cannabinoids. The 10-100-ng/mL cannabinoid concentration range essential for detection of occasional and moderate marijuana users is thus unaffected by realistic passive inhalation.

  2. A realist evaluation of the management of a well- performing regional hospital in Ghana

    PubMed Central

    2010-01-01

    Background Realist evaluation offers an interesting approach to evaluation of interventions in complex settings, but has been little applied in health care. We report on a realist case study of a well performing hospital in Ghana and show how such a realist evaluation design can help to overcome the limited external validity of a traditional case study. Methods We developed a realist evaluation framework for hypothesis formulation, data collection, data analysis and synthesis of the findings. Focusing on the role of human resource management in hospital performance, we formulated our hypothesis around the high commitment management concept. Mixed methods were used in data collection, including individual and group interviews, observations and document reviews. Results We found that the human resource management approach (the actual intervention) included induction of new staff, training and personal development, good communication and information sharing, and decentralised decision-making. We identified 3 additional practices: ensuring optimal physical working conditions, access to top managers and managers' involvement on the work floor. Teamwork, recognition and trust emerged as key elements of the organisational climate. Interviewees reported high levels of organisational commitment. The analysis unearthed perceived organisational support and reciprocity as underlying mechanisms that link the management practices with commitment. Methodologically, we found that realist evaluation can be fruitfully used to develop detailed case studies that analyse how management interventions work and in which conditions. Analysing the links between intervention, mechanism and outcome increases the explaining power, while identification of essential context elements improves the usefulness of the findings for decision-makers in other settings (external validity). We also identified a number of practical difficulties and priorities for further methodological development

  3. Search for a Realistic Orbifold Grand Unification

    SciTech Connect

    Kawamura, Yoshiharu

    2008-05-13

    We review the prototype model of a grand unified theory on the orbifold S{sup 1}/Z{sub 2} and discuss topics related to the choice of boundary conditions; the dynamical rearrangement of gauge symmetry and the equivalence classes of BCs. We explore a family unification scenario by orbifolding.

  4. Synthetic Tumor Networks for Screening Drug Delivery Systems

    PubMed Central

    Prabhakarpandian, Balabhaskar; Shen, Ming-Che; Nichols, Joseph B.; Garson, Charles J.; Mills, Ivy R.; Matar, Majed M.; Fewell, Jason G.; Pant, Kapil

    2015-01-01

    Tumor drug delivery is a complex phenomenon affected by several elements in addition to drug or delivery vehicle’s physico-chemical properties. A key factor is tumor microvasculature with complex effects including convective transport, high interstitial pressure and enhanced vascular permeability due to the presence of “leaky vessels”. Current in vitro models of the tumor microenvironment for evaluating drug delivery are oversimplified and, as a result, show poor correlation with in vivo performance. In this study, we report on the development of a novel microfluidic platform that models the tumor microenvironment more accurately, with physiologically and morphologically realistic microvasculature including endothelial cell lined leaky capillary vessels along with 3D solid tumors. Endothelial cells and 3D spheroids of cervical tumor cells were co-cultured in the networks. Drug vehicle screening was demonstrated using GFP gene delivery by different formulations of nanopolymers. The synthetic tumor network was successful in predicting in vivo delivery efficiencies of the drug vehicles. The developed assay will have critical applications both in basic research, where it can be used to develop next generation delivery vehicles, and in drug discovery where it can be used to study drug transport and delivery efficacy in realistic tumor microenvironment, thereby enabling drug compound and/or delivery vehicle screening. PMID:25599856

  5. Synthetic tumor networks for screening drug delivery systems.

    PubMed

    Prabhakarpandian, Balabhaskar; Shen, Ming-Che; Nichols, Joseph B; Garson, Charles J; Mills, Ivy R; Matar, Majed M; Fewell, Jason G; Pant, Kapil

    2015-03-10

    Tumor drug delivery is a complex phenomenon affected by several elements in addition to drug or delivery vehicle's physico-chemical properties. A key factor is tumor microvasculature with complex effects including convective transport, high interstitial pressure and enhanced vascular permeability due to the presence of "leaky vessels". Current in vitro models of the tumor microenvironment for evaluating drug delivery are oversimplified and, as a result, show poor correlation with in vivo performance. In this study, we report on the development of a novel microfluidic platform that models the tumor microenvironment more accurately, with physiologically and morphologically realistic microvasculature including endothelial cell lined leaky capillary vessels along with 3D solid tumors. Endothelial cells and 3D spheroids of cervical tumor cells were co-cultured in the networks. Drug vehicle screening was demonstrated using GFP gene delivery by different formulations of nanopolymers. The synthetic tumor network was successful in predicting in vivo delivery efficiencies of the drug vehicles. The developed assay will have critical applications both in basic research, where it can be used to develop next generation delivery vehicles, and in drug discovery where it can be used to study drug transport and delivery efficacy in realistic tumor microenvironment, thereby enabling drug compound and/or delivery vehicle screening. PMID:25599856

  6. Towards a realistic prediction of the solar wind plasma microinstabilities

    NASA Astrophysics Data System (ADS)

    Lazar, Marian; Poedts, Stefaan; Schlickeiser, Reinhard

    2015-04-01

    Two scenarios are known for the origin of the field and density fluctuations observed in the solar wind. Thus, the fluctuations can be induced at different scales, either locally and self-consistently by the kinetic anisotropy of plasma particles, or can be injected at larger scales closer to the Sun and then decayed and transported by the super-Alfvénic wind. In both scenarios, details of the plasma microstates - the particle velocity distributions (VDFs), are needed for an accurate description of the fluctuations. In-situ measurements reveal nonequilibrium plasmas with VDFs comprising two major components, a Maxwellian (thermal) core and a less dense but hotter suprathermal halo with a power-law distribution best described by the Kappa models, and the field-aligned strahl as a third component, usually assimilated with the suprathermal populations. Despite this observational evidence, the existing attempts to parameterize the observed (anisotropic) distributions and the supporting fluctuations and instabilities are limited to simplified models, which either ignore the suprathermal halo or just minimize the role of the core assuming it cold, or artificially incorporates both the core and halo in a single, global Kappa that is nearly Maxwellian at low speeds and decreases smoothly as a power law at high speeds. Simplified models imply a reduced number of plasma parameters and are convenient computationally, but they omit important kinetic effects of the plasma particles. Realistic models imply a large number of parameters, especially in the presence of kinetic anisotropies, and make it difficult to identify the instability conditions. However, in a recent endeavor to investigate nonindealized situations when both the core and halo temperatures are finite and anisotropic, we found computationally tractable such a complex model that combines an anisotropic bi-Maxwellian core and an anisotropic bi-Kappa halo. This model is relevant for the slow wind conditions and, in

  7. Non-invasive, photonics-based diagnostic, imaging, monitoring, and light delivery techniques for the recognition, quantification and treatment of malignant and chronic inflammatory conditions

    NASA Astrophysics Data System (ADS)

    Davies, N.; Davies-Shaw, D.; Shaw, J. D.

    2007-02-01

    We report firsthand on innovative developments in non-invasive, biophotonic techniques for a wide range of diagnostic, imaging and treatment options, including the recognition and quantification of cancerous, pre-cancerous cells and chronic inflammatory conditions. These techniques have benefited from the ability to target the affected site by both monochromatic light and broad multiple wavelength spectra. The employment of such wavelength or color-specific properties embraces the fluorescence stimulation of various photosensitizing drugs, and the instigation and detection of identified fluorescence signatures attendant upon laser induced fluorescence (LIF) phenomena as transmitted and propagated by precancerous, cancerous and normal tissue. In terms of tumor imaging and therapeutic and treatment options, we have exploited the abilities of various wavelengths to penetrate to different depths, through different types of tissues, and have explored quantifiable absorption and reflection characteristics upon which diagnostic assumptions can be reliably based and formulated. These biophotonic-based diagnostic, sensing and imaging techniques have also benefited from, and have been further enhanced by, the integrated ability to provide various power levels to be employed at various stages in the procedure. Applications are myriad, including non-invasive, non destructive diagnosis of in vivo cell characteristics and functions; light-based tissue analysis; real-time monitoring and mapping of brain function and of tumor growth; real time monitoring of the surgical completeness of tumor removal during laser-imaged/guided brain resection; diagnostic procedures based on fluorescence life-time monitoring, the monitoring of chronic inflammatory conditions (including rheumatoid arthritis), and continuous blood glucose monitoring in the control of diabetes.

  8. An immersed-boundary framework for patient-specific optimization of inhaled drug delivery

    NASA Astrophysics Data System (ADS)

    Nicolaou, Laura; Zaki, Tamer

    2014-11-01

    Predictive numerical simulations have the potential to significantly enhance therapies for lung disease by providing a valuable clinical aid and a platform to optimize drug delivery. A difficult challenge, however, is the influence of inter-subject variations of the airway geometries and their impact on the airflow and aerosol deposition. A personalized approach to the treatment of respiratory diseases is therefore required. An in silico framework for patient-specific predictions of the flow and aerosol deposition in the respiratory airways is presented. The approach efficiently accommodates geometric variation and airway motion in order to optimize pulmonary drug delivery. A non-rigid registration method is adopted to construct dynamic airway models conforming to the patient's breathing. Accurate predictions of the flow in realistic airway geometries are computed using direct numerical simulations (DNS) with boundary conditions enforced using a robust, implicit immersed boundary (IB) method for curvilinear meshes. A Lagrangian particle-tracking scheme is adopted to model the transport and deposition of the aerosol particles in the airways. Examples of flow and aerosol deposition in realistic extrathoracic airways and of a patient-specific dynamic lung model are presented.

  9. The use and limitation of realistic evaluation as a tool for evidence-based practice: a critical realist perspective.

    PubMed

    Porter, Sam; O'Halloran, Peter

    2012-03-01

    The use and limitation of realistic evaluation as a tool for evidence-based practice: a critical realist perspective In this paper, we assess realistic evaluation's articulation with evidence-based practice (EBP) from the perspective of critical realism. We argue that the adoption by realistic evaluation of a realist causal ontology means that it is better placed to explain complex healthcare interventions than the traditional method used by EBP, the randomized controlled trial (RCT). However, we do not conclude from this that the use of RCTs is without merit, arguing that it is possible to use both methods in combination under the rubric of realist theory. More negatively, we contend that the rejection of critical theory and utopianism by realistic evaluation in favour of the pragmatism of piecemeal social engineering means that it is vulnerable to accusations that it promotes technocratic interpretations of human problems. We conclude that, insofar as realistic evaluation adheres to the ontology of critical realism, it provides a sound contribution to EBP, but insofar as it rejects the critical turn of Bhaskar's realism, it replicates the technocratic tendencies inherent in EBP. PMID:22212367

  10. Competence of birth attendants at providing emergency obstetric care under India’s JSY conditional cash transfer program for institutional delivery: an assessment using case vignettes in Madhya Pradesh province

    PubMed Central

    2014-01-01

    Background Access to emergency obstetric care by competent staff can reduce maternal mortality. India has launched the Janani Suraksha Yojana (JSY) conditional cash transfer program to promote institutional births. During implementation of the JSY, India witnessed a steep increase in the proportion of institutional deliveries-from 40% in 2004 to 73% in 2012. However, maternal mortality reduction follows a secular trend. Competent management of complications, when women deliver in facilities under the JSY, is essential for reduction in maternal mortality and therefore to a successful program outcome. We investigate, using clinical vignettes, whether birth attendants at institutions under the program are competent at providing appropriate care for obstetric complications. Methods A facility based cross-sectional study was conducted in three districts of Madhya Pradesh (MP) province. Written case vignettes for two obstetric complications, hemorrhage and eclampsia, were administered to 233 birth attendant nurses at 73 JSY facilities. Their competence at (a) initial assessment, (b) diagnosis, and (c) making decisions on appropriate first-line care for these complications was scored. Results The mean emergency obstetric care (EmOC) competence score was 5.4 (median = 5) on a total score of 20, and 75% of participants scored below 35% of the maximum score. The overall score, although poor, was marginally higher in respondents with Skilled Birth Attendant (SBA) training, those with general nursing and midwifery qualifications, those at higher facility levels, and those conducting >30 deliveries a month. In all, 14% of respondents were competent at assessment, 58% were competent at making a correct clinical diagnosis, and 20% were competent at providing first-line care. Conclusions Birth attendants in the JSY facilities have low competence at EmOC provision. Hence, births in the JSY program cannot be considered to have access to competent EmOC. Urgent efforts are

  11. Challenges of nurse delivery of psychological interventions for long-term conditions in primary care: a qualitative exploration of the case of chronic fatigue syndrome/myalgic encephalitis

    PubMed Central

    2011-01-01

    Background The evidence base for a range of psychosocial and behavioural interventions in managing and supporting patients with long-term conditions (LTCs) is now well-established. With increasing numbers of such patients being managed in primary care, and a shortage of specialists in psychology and behavioural management to deliver interventions, therapeutic interventions are increasingly being delivered by general nurses with limited training in psychological interventions. It is unknown what issues this raises for the nurses or their patients. The purpose of the study was to examine the challenges faced by non-specialist nurses when delivering psychological interventions for an LTC (chronic fatigue syndrome/myalgic encephalomyelitis [CFS/ME]) within a primary care setting. Methods A qualitative study nested within a randomised controlled trial [ISRCTN 74156610] explored the experiences and acceptability of two different psychological interventions (pragmatic rehabilitation and supportive listening) from the perspectives of nurses, their supervisors, and patients. Semi structured in-depth interviews were conducted with three nurse therapists, three supervisors, and 46 patients. An iterative approach was used to develop conceptual categories from the dataset. Results Analyses identified four sets of challenges that were common to both interventions: (i) being a novice therapist, (ii) engaging patients in the therapeutic model, (iii) dealing with emotions, and (iv) the complexity of primary care. Each challenge had the potential to cause tension between therapist and patient. A number of strategies were developed by participants to manage the tensions. Conclusions Tensions existed for nurses when attempting to deliver psychological interventions for patients with CFS/ME in this primary care trial. Such tensions should be addressed before implementing psychological interventions within routine clinical practice. Similar tensions may be found for other LTCs. Our

  12. Conceptual priming for realistic auditory scenes and for auditory words.

    PubMed

    Frey, Aline; Aramaki, Mitsuko; Besson, Mireille

    2014-02-01

    Two experiments were conducted using both behavioral and Event-Related brain Potentials methods to examine conceptual priming effects for realistic auditory scenes and for auditory words. Prime and target sounds were presented in four stimulus combinations: Sound-Sound, Word-Sound, Sound-Word and Word-Word. Within each combination, targets were conceptually related to the prime, unrelated or ambiguous. In Experiment 1, participants were asked to judge whether the primes and targets fit together (explicit task) and in Experiment 2 they had to decide whether the target was typical or ambiguous (implicit task). In both experiments and in the four stimulus combinations, reaction times and/or error rates were longer/higher and the N400 component was larger to ambiguous targets than to conceptually related targets, thereby pointing to a common conceptual system for processing auditory scenes and linguistic stimuli in both explicit and implicit tasks. However, fine-grained analyses also revealed some differences between experiments and conditions in scalp topography and duration of the priming effects possibly reflecting differences in the integration of perceptual and cognitive attributes of linguistic and nonlinguistic sounds. These results have clear implications for the building-up of virtual environments that need to convey meaning without words. PMID:24378910

  13. Convective aggregation in idealised models and realistic equatorial cases

    NASA Astrophysics Data System (ADS)

    Holloway, Chris

    2015-04-01

    Idealised explicit convection simulations of the Met Office Unified Model are shown to exhibit spontaneous self-aggregation in radiative-convective equilibrium, as seen previously in other models in several recent studies. This self-aggregation is linked to feedbacks between radiation, surface fluxes, and convection, and the organization is intimately related to the evolution of the column water vapour (CWV) field. To investigate the relevance of this behaviour to the real world, these idealized simulations are compared with five 15-day cases of real organized convection in the tropics, including multiple simulations of each case testing sensitivities of the convective organization and mean states to interactive radiation, interactive surface fluxes, and evaporation of rain. Despite similar large-scale forcing via lateral boundary conditions, systematic differences in mean CWV, CWV distribution shape, and the length scale of CWV features are found between the different sensitivity runs, showing that there are at least some similarities in sensitivities to these feedbacks in both idealized and realistic simulations.

  14. Unsteady transonic algorithm improvements for realistic aircraft applications

    NASA Technical Reports Server (NTRS)

    Batina, John T.

    1987-01-01

    Improvements to a time-accurate approximate factorization (AF) algorithm were implemented for steady and unsteady transonic analysis of realistic aircraft configurations. These algorithm improvements were made to the CAP-TSD (Computational Aeroelasticity Program - Transonic Small Disturbance) code developed at the Langley Research Center. The code permits the aeroelastic analysis of complete aircraft in the flutter critical transonic speed range. The AF algorithm of the CAP-TSD code solves the unsteady transonic small-disturbance equation. The algorithm improvements include: an Engquist-Osher (E-O) type-dependent switch to more accurately and efficiently treat regions of supersonic flow; extension of the E-O switch for second-order spatial accuracy in these regions; nonreflecting far field boundary conditions for more accurate unsteady applications; and several modifications which accelerate convergence to steady-state. Calculations are presented for several configurations including the General Dynamics one-ninth scale F-16C aircraft model to evaluate the algorithm modifications. The modifications have significantly improved the stability of the AF algorithm and hence the reliability of the CAP-TSD code in general.

  15. Effects of realistic tensor force on nuclear structure

    SciTech Connect

    Nakada, H.

    2012-10-20

    First-order tensor-force effects on nuclear structure are investigated in the self-consistent mean-field and RPA calculations with the M3Y-type semi-realistic interactions, which contain the realistic tensor force. The tensor force plays a key role in Z- or N-dependence of the shell structure, and in transitions involving spin degrees-of-freedom. It is demonstrated that the semi-realistic interactions successfully describe the N-dependence of the shell structure in the proton-magic nuclei (e.g. Ca and Sn), and the magnetic transitions (e.g. M1 transition in {sup 208}Pb).

  16. Metastable cosmic strings in realistic models

    SciTech Connect

    Holman, R.; Hsu, S.; Vachaspati, T.; Watkins, R. |

    1992-11-01

    The stability of the electroweak Z-string is investigated at high temperatures. The results show that, while finite temperature corrections can improve the stability of the Z-string, their effect is not strong enough to stabilize the Z-string in the standard electroweak model. Consequently, the Z-string will be unstable even under the conditions present during the electroweak phase transition. Phenomenologically viable models based on the gauge group SU(2){sub L} {times} SU(2) {sub R} {times} U(1){sub B-L} are then considered, and it is shown that metastable strings exist and are stable to small perturbations for a large region of the parameter space for these models. It is also shown that these strings are superconducting with bosonic charge carriers. The string superconductivity may be able to stabilize segments and loops against dynamical contraction. Possible implications of these strings for cosmology are discussed.

  17. Metastable cosmic strings in realistic models

    SciTech Connect

    Holman, R. . Dept. of Physics); Hsu, S. . Lyman Lab. of Physics); Vachaspati, T. . Dept. of Physics and Astronomy); Watkins, R. Fermi National Accelerator Lab., Batavia, IL )

    1992-01-01

    The stability of the electroweak Z-string is investigated at high temperatures. The results show that, while finite temperature corrections can improve the stability of the Z-string, their effect is not strong enough to stabilize the Z-string in the standard electroweak model. Consequently, the Z-string will be unstable even under the conditions present during the electroweak phase transition. Phenomenologically viable models based on the gauge group SU(2)[sub L] [times] SU(2) [sub R] [times] U(1)[sub B-L] are then considered, and it is shown that metastable strings exist and are stable to small perturbations for a large region of the parameter space for these models. It is also shown that these strings are superconducting with bosonic charge carriers. The string superconductivity may be able to stabilize segments and loops against dynamical contraction. Possible implications of these strings for cosmology are discussed.

  18. Toward a realistic low-field SSC lattice

    SciTech Connect

    Heifets, S.

    1985-10-01

    Three six-fold lattices for 3 T superferric SSC have been generated at TAC. The program based on the first order canonical transformation was used to compare lattices. On this basis the realistic race-track lattices were generated.

  19. Student Work Experience: A Realistic Approach to Merchandising Education.

    ERIC Educational Resources Information Center

    Horridge, Patricia; And Others

    1980-01-01

    Relevant and realistic experiences are needed to prepare the student for a future career. Addresses the results of a survey of colleges and universities in the United States in regard to their student work experience (SWE) in fashion merchandising. (Author)

  20. Obscurant representation for realistic IR simulation

    NASA Astrophysics Data System (ADS)

    Gozard, Patrick; Le Goff, Alain; Cathala, Thierry; Latger, Jean; Boudet, Antoine

    2003-09-01

    Obscurant representation is a key component of ground battlefield simulation, especially in the infrared domain. Obscurant are special counter measures (clouds) classically used to hide armored vehicles and deceive threatens. Obscurants are very difficult to represent especially because of multi diffusion effects of hot particles and smoke, but this representation is very important to quantify the efficiency of the decoy. This article describes a new model being involved in the simulation workshop CHORALE of the French MoD. The simulation workshop CHORALE developed in collaboration with OKTAL SE company is used by government services and industrial companies for weapon system validation and qualification trials in the infrared domain. The main operational reference for CHORALE is the assessment of the infrared guidance system of the Storm Shadow missile French version, called Scalp. This new model, integrated in CHORALE, enables to simulate the emitted radiance and the transmission of any pre computed obscurant cloud in the virtual battlefield. In the modeling step, the cloud is defined by a set of "voxels" (elementary volume elements). Each voxel contains the spectral extinction coefficient and the spectral scattering coefficients. The shape, i.e. the voxels content, is changing with time to convey the dynamic evolution of the obscurant. In the Non Real Time rendering step, primary rays are traced inside the clouds. For each voxel, scattering rays are then traced to their neighboring voxels and the local hot sources. Actually, ray tracing is used to solve the Radiative Transfer Equation. The main advantage is to be able to solve it taking into account the synthetic environment: the local terrain, the target hidden in the cloud, the atmospheric and weather conditions. The main originality is the multithreading ray tracing which enables to tackle huge quantities of rays in complex geometric environment.

  1. Ocular delivery of macromolecules

    PubMed Central

    Kim, Yoo-Chun; Chiang, Bryce; Wu, Xianggen; Prausnitz, Mark R.

    2014-01-01

    Biopharmaceuticals are making increasing impact on medicine, including treatment of indications in the eye. Macromolecular drugs are typically given by physician-administered invasive delivery methods, because non--invasive ocular delivery methods, such as eye drops, and systemic delivery, have low bioavailability and/or poor ocular targeting. There is a need to improve delivery of biopharmaceuticals to enable less-invasive delivery routes, less-frequent dosing through controlled-release drug delivery and improved drug targeting within the eye to increase efficacy and reduce side effects. This review discusses the barriers to drug delivery via various ophthalmic routes of administration in the context of macromolecule delivery and discusses efforts to develop controlled-release systems for delivery of biopharmaceuticals to the eye. The growing number of macromolecular therapies in the eye needs improved drug delivery methods that increase drug efficacy, safety and patient compliance. PMID:24998941

  2. Realistic Image Rendition Using a Variable Exponent Functional Model for Retinex.

    PubMed

    Dou, Zeyang; Gao, Kun; Zhang, Bin; Yu, Xinyan; Han, Lu; Zhu, Zhenyu

    2016-01-01

    The goal of realistic image rendition is to recover the acquired image under imperfect illuminant conditions, where non-uniform illumination may degrade image quality with high contrast and low SNR. In this paper, the assumption regarding illumination is modified and a variable exponent functional model for Retinex is proposed to remove non-uniform illumination and reduce halo artifacts. The theoretical derivation is provided and experimental results are presented to illustrate the effectiveness of the proposed model. PMID:27338379

  3. Realistic Image Rendition Using a Variable Exponent Functional Model for Retinex

    PubMed Central

    Dou, Zeyang; Gao, Kun; Zhang, Bin; Yu, Xinyan; Han, Lu; Zhu, Zhenyu

    2016-01-01

    The goal of realistic image rendition is to recover the acquired image under imperfect illuminant conditions, where non–uniform illumination may degrade image quality with high contrast and low SNR. In this paper, the assumption regarding illumination is modified and a variable exponent functional model for Retinex is proposed to remove non–uniform illumination and reduce halo artifacts. The theoretical derivation is provided and experimental results are presented to illustrate the effectiveness of the proposed model. PMID:27338379

  4. The visualizable, the representable and the inconceivable: realist and non-realist mathematical models in physics and beyond.

    PubMed

    Plotnitsky, Arkady

    2016-01-13

    The project of this article is twofold. First, it aims to offer a new perspective on, and a new argument concerning, realist and non-realist mathematical models, and differences and affinities between them, using physics as a paradigmatic field of mathematical modelling in science. Most of the article is devoted to this topic. Second, the article aims to explore the implications of this argument for mathematical modelling in other fields, in particular in cognitive psychology and economics. PMID:26621990

  5. Non-tachyonic semi-realistic non-supersymmetric heterotic-string vacua

    NASA Astrophysics Data System (ADS)

    Ashfaque, Johar M.; Athanasopoulos, Panos; Faraggi, Alon E.; Sonmez, Hasan

    2016-04-01

    The heterotic-string models in the free fermionic formulation gave rise to some of the most realistic-string models to date, which possess N=1 spacetime supersymmetry. Lack of evidence for supersymmetry at the LHC instigated recent interest in non-supersymmetric heterotic-string vacua. We explore what may be learned in this context from the quasi-realistic free fermionic models. We show that constructions with a low number of families give rise to proliferation of a priori tachyon producing sectors, compared to the non-realistic examples, which typically may contain only one such sector. The reason being that in the realistic cases the internal six dimensional space is fragmented into smaller units. We present one example of a quasi-realistic, non-supersymmetric, non-tachyonic, heterotic-string vacuum and compare the structure of its massless spectrum to the corresponding supersymmetric vacuum. While in some sectors supersymmetry is broken explicitly, i.e. the bosonic and fermionic sectors produce massless and massive states, other sectors, and in particular those leading to the chiral families, continue to exhibit Fermi-Bose degeneracy. In these sectors the massless spectrum, as compared to the supersymmetric cases, will only differ in some local or global U(1) charges. We discuss the conditions for obtaining n_b=n_f at the massless level in these models. Our example model contains an anomalous U(1) symmetry, which generates a tadpole diagram at one-loop order in string perturbation theory. We speculate that this tadpole diagram may cancel the corresponding diagram generated by the one-loop non-vanishing vacuum energy and that in this respect the supersymmetric and non-supersymmetric vacua should be regarded on an equal footing. Finally we discuss vacua that contain two supersymmetry generating sectors.

  6. Transdermal drug delivery

    PubMed Central

    Prausnitz, Mark R.; Langer, Robert

    2009-01-01

    Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, non-cavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin’s barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Microneedles and thermal ablation are currently progressing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase impact on medicine. PMID:18997767

  7. How does capacity building of health managers work? A realist evaluation study protocol

    PubMed Central

    Marchal, Bruno; Hoeree, Tom; Devadasan, Narayanan; Macq, Jean; Kegels, Guy; Criel, Bart

    2012-01-01

    Introduction There has been a lot of attention on the role of human resource management interventions to improve delivery of health services in low- and middle-income countries. However, studies on this subject are few due to limited research on implementation of programmes and methodological difficulties in conducting experimental studies on human resource interventions. The authors present the protocol of an evaluation of a district-level capacity-building intervention to identify the determinants of performance of health workers in managerial positions and to understand how changes (if any) are brought about. Methods and analysis The aim of this study is to understand how capacity building works. The authors will use realist evaluation to evaluate an intervention in Karnataka, India. The intervention is a capacity-building programme that seeks to improve management capacities of health managers at district and subdistrict levels through periodic classroom-based teaching and mentoring support at the workplace. The authors conducted interviews and reviewed literature on capacity building in health to draw out the programme theory of the intervention. Based on this, the authors formulated hypothetical pathways connecting the expected outcomes of the intervention (planning and supervision) to the inputs (contact classes and mentoring). The authors prepared a questionnaire to assess elements of the programme theory—organisational culture, self-efficacy and supervision. The authors shall conduct a survey among health managers as well as collect qualitative data through interviews with participants and non-participants selected purposively based on their planning and supervision performance. The authors will construct explanations in the form of context–mechanism–outcome configurations from the results. This will be iterative and the authors will use a realist evaluation framework to refine the explanatory theories that are based on the findings to explain and

  8. Realistic real-time outdoor rendering in augmented reality.

    PubMed

    Kolivand, Hoshang; Sunar, Mohd Shahrizal

    2014-01-01

    Realistic rendering techniques of outdoor Augmented Reality (AR) has been an attractive topic since the last two decades considering the sizeable amount of publications in computer graphics. Realistic virtual objects in outdoor rendering AR systems require sophisticated effects such as: shadows, daylight and interactions between sky colours and virtual as well as real objects. A few realistic rendering techniques have been designed to overcome this obstacle, most of which are related to non real-time rendering. However, the problem still remains, especially in outdoor rendering. This paper proposed a much newer, unique technique to achieve realistic real-time outdoor rendering, while taking into account the interaction between sky colours and objects in AR systems with respect to shadows in any specific location, date and time. This approach involves three main phases, which cover different outdoor AR rendering requirements. Firstly, sky colour was generated with respect to the position of the sun. Second step involves the shadow generation algorithm, Z-Partitioning: Gaussian and Fog Shadow Maps (Z-GaF Shadow Maps). Lastly, a technique to integrate sky colours and shadows through its effects on virtual objects in the AR system, is introduced. The experimental results reveal that the proposed technique has significantly improved the realism of real-time outdoor AR rendering, thus solving the problem of realistic AR systems. PMID:25268480

  9. Using polychromatic X-radiography to examine realistic imitation firearms.

    PubMed

    Austin, J C; Day, C R; Kearon, A T; Valussi, S; Haycock, P W

    2008-10-25

    Sections 36-41 of the Violent Crimes Reduction Act (2006), which came into force in England and Wales on 1st October 2007, have placed significant restrictions on the sale and possession of 'realistic imitation firearms'. This legislation attempts to produce a definition of a 'realistic imitation' which clearly differentiates these items from other imitation firearms (which are not covered by the legislation). This paper will go a stage further by demonstrating techniques by which blank firing realistic imitation firearms which may be suitable for illegal conversion to fire live rounds may be differentiated from other less 'suitable' (but visually identical) realistic imitations. The article reports on the use of X-radiography, utilizing the bremsstrahlung of a commercial broad spectrum X-ray source, to identify the differences between alloys constituting the barrels of distinct replica and/or blank firing handguns. The resulting pseudo-signatures are transmission spectra over a range from 20 to 75 kV, taken at 1 kV intervals, which are extracted from stacks of registered, field flattened images. It is shown that it is possible to quantify differences between transmission spectra for components of different realistic imitation fire arms, and apply the results to determine the suitability of particular gun barrels from blank firing imitation firearms for illegal conversion to fire live rounds, or related illegal modifications. PMID:18842365

  10. Realistic modeling of neurons and networks: towards brain simulation

    PubMed Central

    D’Angelo, Egidio; Solinas, Sergio; Garrido, Jesus; Casellato, Claudia; Pedrocchi, Alessandra; Mapelli, Jonathan; Gandolfi, Daniela; Prestori, Francesca

    Summary Realistic modeling is a new advanced methodology for investigating brain functions. Realistic modeling is based on a detailed biophysical description of neurons and synapses, which can be integrated into microcircuits. The latter can, in turn, be further integrated to form large-scale brain networks and eventually to reconstruct complex brain systems. Here we provide a review of the realistic simulation strategy and use the cerebellar network as an example. This network has been carefully investigated at molecular and cellular level and has been the object of intense theoretical investigation. The cerebellum is thought to lie at the core of the forward controller operations of the brain and to implement timing and sensory prediction functions. The cerebellum is well described and provides a challenging field in which one of the most advanced realistic microcircuit models has been generated. We illustrate how these models can be elaborated and embedded into robotic control systems to gain insight into how the cellular properties of cerebellar neurons emerge in integrated behaviors. Realistic network modeling opens up new perspectives for the investigation of brain pathologies and for the neurorobotic field. PMID:24139652

  11. Realistic Real-Time Outdoor Rendering in Augmented Reality

    PubMed Central

    Kolivand, Hoshang; Sunar, Mohd Shahrizal

    2014-01-01

    Realistic rendering techniques of outdoor Augmented Reality (AR) has been an attractive topic since the last two decades considering the sizeable amount of publications in computer graphics. Realistic virtual objects in outdoor rendering AR systems require sophisticated effects such as: shadows, daylight and interactions between sky colours and virtual as well as real objects. A few realistic rendering techniques have been designed to overcome this obstacle, most of which are related to non real-time rendering. However, the problem still remains, especially in outdoor rendering. This paper proposed a much newer, unique technique to achieve realistic real-time outdoor rendering, while taking into account the interaction between sky colours and objects in AR systems with respect to shadows in any specific location, date and time. This approach involves three main phases, which cover different outdoor AR rendering requirements. Firstly, sky colour was generated with respect to the position of the sun. Second step involves the shadow generation algorithm, Z-Partitioning: Gaussian and Fog Shadow Maps (Z-GaF Shadow Maps). Lastly, a technique to integrate sky colours and shadows through its effects on virtual objects in the AR system, is introduced. The experimental results reveal that the proposed technique has significantly improved the realism of real-time outdoor AR rendering, thus solving the problem of realistic AR systems. PMID:25268480

  12. 43 CFR 418.7 - Who may receive irrigation deliveries.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 1 2014-10-01 2014-10-01 false Who may receive irrigation deliveries. 418.7 Section 418.7 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION... Conditions of Water Delivery § 418.7 Who may receive irrigation deliveries. Project irrigation...

  13. 43 CFR 418.7 - Who may receive irrigation deliveries.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 1 2012-10-01 2011-10-01 true Who may receive irrigation deliveries. 418.7 Section 418.7 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION... Conditions of Water Delivery § 418.7 Who may receive irrigation deliveries. Project irrigation...

  14. 43 CFR 418.7 - Who may receive irrigation deliveries.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 1 2011-10-01 2011-10-01 false Who may receive irrigation deliveries. 418.7 Section 418.7 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION... Conditions of Water Delivery § 418.7 Who may receive irrigation deliveries. Project irrigation...

  15. 43 CFR 418.7 - Who may receive irrigation deliveries.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 1 2013-10-01 2013-10-01 false Who may receive irrigation deliveries. 418.7 Section 418.7 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION... Conditions of Water Delivery § 418.7 Who may receive irrigation deliveries. Project irrigation...

  16. 43 CFR 418.7 - Who may receive irrigation deliveries.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Who may receive irrigation deliveries. 418.7 Section 418.7 Public Lands: Interior Regulations Relating to Public Lands BUREAU OF RECLAMATION... Conditions of Water Delivery § 418.7 Who may receive irrigation deliveries. Project irrigation...

  17. Optimizing Wind And Hydropower Generation Within Realistic Reservoir Operating Policy

    NASA Astrophysics Data System (ADS)

    Magee, T. M.; Clement, M. A.; Zagona, E. A.

    2012-12-01

    Previous studies have evaluated the benefits of utilizing the flexibility of hydropower systems to balance the variability and uncertainty of wind generation. However, previous hydropower and wind coordination studies have simplified non-power constraints on reservoir systems. For example, some studies have only included hydropower constraints on minimum and maximum storage volumes and minimum and maximum plant discharges. The methodology presented here utilizes the pre-emptive linear goal programming optimization solver in RiverWare to model hydropower operations with a set of prioritized policy constraints and objectives based on realistic policies that govern the operation of actual hydropower systems, including licensing constraints, environmental constraints, water management and power objectives. This approach accounts for the fact that not all policy constraints are of equal importance. For example target environmental flow levels may not be satisfied if it would require violating license minimum or maximum storages (pool elevations), but environmental flow constraints will be satisfied before optimizing power generation. Additionally, this work not only models the economic value of energy from the combined hydropower and wind system, it also captures the economic value of ancillary services provided by the hydropower resources. It is recognized that the increased variability and uncertainty inherent with increased wind penetration levels requires an increase in ancillary services. In regions with liberalized markets for ancillary services, a significant portion of hydropower revenue can result from providing ancillary services. Thus, ancillary services should be accounted for when determining the total value of a hydropower system integrated with wind generation. This research shows that the end value of integrated hydropower and wind generation is dependent on a number of factors that can vary by location. Wind factors include wind penetration level

  18. A computer-controlled pump and realistic anthropomorphic respiratory phantom for validating image-guided systems

    NASA Astrophysics Data System (ADS)

    Lin, Ralph; Wilson, Emmanuel; Tang, Jonathan; Stoianovici, Dan; Cleary, Kevin

    2007-03-01

    The development of image-guided interventions requires validation studies to evaluate new protocols. So far, these validation studies have been limited to animal models and to software and physical phantoms that simulate respiratory motion but cannot accommodate needle punctures in a realistic manner. We have built a computer-controlled pump that drives an anthropomorphic respiratory phantom for simulating natural breathing patterns. This pump consists of a power supply, a motion controller with servo amplifier, linear actuator, and custom fabricated pump assembly. By generating several sample waveforms, we were able to simulate typical breathing patterns. Using this pump, we were able to produce chest wall movements similar to typical chest wall movements observed in humans. This system has potential applications for evaluating new respiratory compensation algorithms and may facilitate improved testing of image-guided protocols under realistic interventional conditions.

  19. Realistic environmental mixtures of hydrophobic compounds do not alter growth of a marine diatom.

    PubMed

    Everaert, Gert; De Laender, Frederik; Claessens, Michiel; Baert, Jan; Monteyne, Els; Roose, Patrick; Goethals, Peter L M; Janssen, Colin R

    2016-01-15

    In this paper we determine whether a realistic mixture of hydrophobic chemicals affects the growth dynamics of a marine diatom and how this effect compares to the effect of temperature, light regime and nutrient conditions. To do so, we examine the specific growth rate of Phaeodactylum tricornutum in a 72 h algal growth inhibition test using a full factorial design with three nutrient regimes, two test temperatures, three light intensities and three chemical exposures. Passive samplers were used to achieve exposure to realistic mixtures of organic chemicals close to ambient concentrations. Nutrient regime, temperature and time interval (24, 48 and 72 h) explained 85% of the observed variability in the experimental data. The variability explained by chemical exposure was about 1%. Overall, ambient concentrations of hydrophobic compounds present in Belgian coastal waters, and for which the passive samplers have affinity, are too low to affect the intrinsic growth rate of P. tricornutum. PMID:26656802

  20. A Distributed Radiator, Heavy Ion Target with Realistic Ion Beams

    NASA Astrophysics Data System (ADS)

    Callahan, Debra A.; Tabak, Max

    1997-11-01

    Recent efforts in heavy ion target design have centered around the distributed radiator design of Tabak(M. Tabak, Bull. Am. Phys. Soc., Vol 41, No 7, 1996.). The initial distributed radiator target assumed beams with a uniform radial density distribution aimed directly along the z axis. Chamber propagation simulations indicate that the beam distribution is more nearly Gaussian at best focus. In addition, more than two beams will be necessary to carry the required current; this means that the beams must be angled to allow space for the final focusing systems upstream. We will describe our modifications to the distributed radiator target to allow realistic beams and realistic beam angles.

  1. The effects of realistic pancake solenoids on particle transport

    SciTech Connect

    Gu, X.; Okamura, M.; Pikin, A.; Fischer, W.; Luo, Y.

    2011-02-01

    Solenoids are widely used to transport or focus particle beams. Usually, they are assumed as being ideal solenoids with a high axial-symmetry magnetic field. Using the Vector Field Opera program, we modeled asymmetrical solenoids with realistic geometry defects, caused by finite conductor and current jumpers. Their multipole magnetic components were analyzed with the Fourier fit method; we present some possible optimized methods for them. We also discuss the effects of 'realistic' solenoids on low energy particle transport. The finding in this paper may be applicable to some lower energy particle transport system design.

  2. Bosonic condensates in realistic supersymmetric GUT cosmic strings

    NASA Astrophysics Data System (ADS)

    Allys, Erwan

    2016-04-01

    We study the realistic structure of F-term Nambu-Goto cosmic strings forming in a general supersymmetric Grand Unified Theory implementation, assuming standard hybrid inflation. Examining the symmetry breaking of the unification gauge group down to the Standard Model, we discuss the minimal field content necessary to describe abelian cosmic strings appearing at the end of inflation. We find that several fields will condense in most theories, questioning the plausible occurrence of associated currents (bosonic and fermionic). We perturbatively evaluate the modification of their energy per unit length due to the condensates. We provide a criterion for comparing the usual abelian Higgs approximation used in cosmology to realistic situations.

  3. Particles and gaseous emissions from realistic operation of residential wood pellet heating systems

    NASA Astrophysics Data System (ADS)

    Win, Kaung Myat; Persson, Tomas; Bales, Chris

    2012-11-01

    Gaseous and particulate emissions from six residential wood pellet heating systems are determined at a realistic six day operation sequence. The study aims to investigate the total emissions from a realistic operation of the heating systems including start-up and stop phases. Five combined solar and pellet heating systems and one reference boiler without solar system with an integrated DHW preparation was tested in a laboratory at realistic operation conditions. The investigated emissions comprised carbon monoxide (CO), nitrogen oxide (NO), total organic carbon (TOC) and particulate matter (PM2.5). In this study, the emissions are presented as accumulated total emissions from the whole six days period and the emissions from start-up and stop phases are also presented separately to evaluate the influence of the emissions from these phases on the total emissions. Emission factors of the measured systems from the six day period are between 192 and 547 mg MJ-1 for the CO emissions, between 61 and 95 mg MJ-1 for the NO, between 6 and 45 mg MJ-1 for the TOC, between 31 and 116 mg MJ-1 for the particulate matter and between 2.1 × 1013 and 4 × 1013 for the number of particles. The emissions from the start-up and stop phases are significantly high for the CO (63-95 %) and the TOC (48-93 %). NO and particles emissions are shown to dominate during stationary operation. However, 30-40 % of the particle emissions arise from the start and stop periods. It is also shown that the average emissions of CO, TOC and particles under the realistic annual conditions were higher than the limit values of two eco labels.

  4. Articulating feedstock delivery device

    DOEpatents

    Jordan, Kevin

    2013-11-05

    A fully articulable feedstock delivery device that is designed to operate at pressure and temperature extremes. The device incorporates an articulating ball assembly which allows for more accurate delivery of the feedstock to a target location. The device is suitable for a variety of applications including, but not limited to, delivery of feedstock to a high-pressure reaction chamber or process zone.

  5. A Realistic Experimental Design and Statistical Analysis Project

    ERIC Educational Resources Information Center

    Muske, Kenneth R.; Myers, John A.

    2007-01-01

    A realistic applied chemical engineering experimental design and statistical analysis project is documented in this article. This project has been implemented as part of the professional development and applied statistics courses at Villanova University over the past five years. The novel aspects of this project are that the students are given a…

  6. Determination of quantum-noise parameters of realistic cavities

    NASA Astrophysics Data System (ADS)

    Semenov, A. A.; Vogel, W.; Khanbekyan, M.; Welsch, D.-G.

    2007-01-01

    A procedure is developed which allows one to measure all the parameters occurring in a complete model [A. A. Semenov , Phys. Rev. A 74, 033803 (2006)] of realistic leaky cavities with unwanted noise. The method is based on the reflection of properly chosen test pulses by the cavity.

  7. International Management: Creating a More Realistic Global Planning Environment.

    ERIC Educational Resources Information Center

    Waldron, Darryl G.

    2000-01-01

    Discusses the need for realistic global planning environments in international business education, introducing a strategic planning model that has teams interacting with teams to strategically analyze a selected multinational company. This dynamic process must result in a single integrated written analysis that specifies an optimal strategy for…

  8. Highly realistic, immersive training for navy corpsmen: preliminary results.

    PubMed

    Booth-Kewley, Stephanie; McWhorter, Stephanie K

    2014-12-01

    Highly realistic, immersive training has been developed for Navy corpsmen based on the success of the Infantry Immersion Trainer. This new training is built around scenarios that are designed to depict real-life, operational situations. Each scenario used in the training includes sights, sounds, smells, and distractions to simulate realistic and challenging combat situations. The primary objective of this study was to assess corpsmen participants' satisfaction with highly realistic training. The study sample consisted of 434 male Navy service members attending Field Medical Training Battalion-West, Camp Pendleton, California. Corpsmen participants completed surveys after receiving the training. Participants expressed high levels of satisfaction with the training overall and with several specific elements of the training. The element of the training that the corpsmen rated the highest was the use of live actors. The vast majority of the participants reported that the training had increased their overall confidence about being successful corpsmen and had strengthened their confidence in their ability to provide care under pressure. Additional research should extend highly realistic training to other military medical provider populations. PMID:25469964

  9. Eliciting Mathematical Thinking of Students through Realistic Mathematics Education

    ERIC Educational Resources Information Center

    Anwar, Lathifu; Budayasa, I Ketut; Amin, Siti M.; de Haan, Dede

    2012-01-01

    This paper focuses on an implementation a sequence of instructional activities about addition of fractions that has been developed and implemented in grade four of primary school in Surabaya, Indonesia. The theory of Realistic Mathematics Education (RME) has been applied in the sequence, which aims to assist low attaining learners in supporting…

  10. Synthesis Of Realistic Animations Of A Person Speaking

    NASA Technical Reports Server (NTRS)

    Scott, Kenneth C.; Kagels, David S.; Watson, Stephen H.; Rom, Hillel S.; Lorre, Jean J.; Wright, John R.; Duxbury, Elizabeth D.

    1995-01-01

    Actors computer program implements automated process that synthesizes realistic animations of person speaking. Produces "newscaster" type video sequences. Uses images of person and, therefore, not limited to cartoons and cartoonlike movies. Potential applications also include use of process for automatically producing on-the-fly animations for human/computer interfaces and for reducing bandwidth needed to transmit video telephone signals.

  11. Developing Skills: Realistic Work Environments in Further Education. FEDA Reports.

    ERIC Educational Resources Information Center

    Armstrong, Paul; Hughes, Maria

    To establish the prevalence and perceived value of realistic work environments (RWEs) in colleges and their use as learning resources, all further education (FE) sector colleges in Great Britain were surveyed in the summer of 1998. Of 175 colleges that responded to 2 questionnaires for senior college managers and RWE managers, 127 had at least 1…

  12. The Potential and Challenges of Critical Realist Ethnography

    ERIC Educational Resources Information Center

    Barron, Ian

    2013-01-01

    This article revisits the critical realist ethnographic process that was adopted in my doctoral thesis, which was concerned with the experiences of ethnic identity of white British and Pakistani British children as they started kindergarten in the northwest of England. The article focuses on the ethnography that emerged from the visits that I…

  13. A SPATIALLY REALISTIC MODEL FOR INFORMING FOREST MANAGEMENT DECISIONS

    EPA Science Inventory

    Spatially realistic population models (SRPMs) address a fundamental
    problem commonly confronted by wildlife managers - predicting the
    effects of landscape-scale habitat management on an animal population.
    SRPMs typically consist of three submodels: (1) a habitat submodel...

  14. Two-Capacitor Problem: A More Realistic View.

    ERIC Educational Resources Information Center

    Powell, R. A.

    1979-01-01

    Discusses the two-capacitor problem by considering the self-inductance of the circuit used and by determining how well the usual series RC circuit approximates the two-capacitor problem when realistic values of L, C, and R are chosen. (GA)

  15. Critical Realist Review: Exploring the Real, beyond the Empirical

    ERIC Educational Resources Information Center

    Edgley, Alison; Stickley, Theodore; Timmons, Stephen; Meal, Andy

    2016-01-01

    This article defines the "critical realist review", a literature-based methodological approach to critical analysis of health care studies (or any discipline charged with social interventions) that is robust, insightful and essential for the complexities of twenty-first century evidence-based health and social care. We argue that this…

  16. The Instructional Effectiveness of Integrating Abstract and Realistic Visualization.

    ERIC Educational Resources Information Center

    Joseph, John H.

    This study examined the question of whether the integration of abstract and realistic visualization can improve the effectiveness of visualized instruction. Two methods of integrating visualizations were investigated. The first method used hybrid illustrations, i.e., a real color photograph into which a line drawing segment has been inserted. This…

  17. Magical Realist Pathways into and under the Psychotherapeutic Imaginary

    ERIC Educational Resources Information Center

    Speedy, Jane

    2011-01-01

    My experience of people's life stories from my work as a narrative therapist consistently destabilised distinctions between imagined/magical and real experiences. I came to realise that the day-to-day magical realist juxtapositions I came upon were encounters with people's daily lives, as lived, that have remained unacknowledged within the…

  18. Realistically Predicting Saturation-Excess Runoff With El-SWAT

    NASA Astrophysics Data System (ADS)

    Hoang, L.; Schneiderman, E. M.; Steenhuis, T. S.; Moore, K. E.; Owens, E. M.

    2015-12-01

    Saturation excess runoff (SER) is without doubt the major runoff mechanism in the humid well vegetated areas where infiltration rates often exceed the medium rainfall intensity. Despite its preponderance, incorporating SER in the distributed models has been slow and fraught with difficulties. The short term objective of this paper to adjust the generally used Soil and Water Assessment Tool (SWAT) to include SER and test the results in the Catskill Mountains that is the source of most of New York City's water. The long term goal is to use the adjusted distributed runoff mechanism in water quality models to aid in the design of effective management practices. The current version of SWAT uses information of soil plant characteristics and hydrologic condition to predict runoff and thus is implicitly based on infiltration-excess runoff. Previous attempts to incorporate SER mechanism in SWAT fell short because they were unable to distribute water from a Hydrological Response Unit (HRU) to another. In the current version called El-SWAT, this shortcoming has been overcome by redefining HRU to include landscape position through the topographic index, grouping the newly defined HRU into wetness classes and by introducing a perched water table with the ability to route interflow from "dryer" to "wetter" HRU wetness classes. Mathematically, the perched aquifer is a non-linear reservoir that generates rapid subsurface stormflow as the perched water table rises. The El-SWAT model was tested in the Town Brook watershed in the upper reaches of the West Branch of the Delaware in the Catskill Mountains. The results showed that El-SWAT could predict discharge well with Nash-Sutcliffe Efficiency of 0.69 and 0.84 for daily and monthly time steps. Compared to the original SWAT model, El-SWAT predicted less surface runoff and groundwater flow and a greater lateral flow component. The saturated areas in El-SWAT were concentrated in locations with high topographic index and was in

  19. Meteorological impact of realistic Terra Nova Bay polynyas.

    NASA Astrophysics Data System (ADS)

    Morelli, Sandra

    2010-05-01

    The energy exchange between the ocean and the atmosphere in the Antarctic marginal sea ice zone is influenced by the extent of sea-ice cover. In areas of open water, a direct contact is established and intense energy exchanges occur, due to the large difference of temperature between the water and the air above it. This implies that the polynyas are areas where the ocean exchanges energy with the atmosphere and as a result they have an effect on the polar meteorology/climate. The work presented here concerns real polynya events in the region of Terra Nova Bay (TNB), Antarctica, where a recurring coastal polynya occurs nearby the Italian Antarctic Base. The aim is the study of the impact of polynyas on the atmosphere by three-dimensional numerical simulations. The ETA model (Mesinger et al., 2006) was used and ECMWF and NCEP data provided the initial and boundary conditions. The model had already been successfully used in the Antarctic area (Casini and Morelli, 2007) A polynya of realistic size (as observed by satellite image) was included in the initial conditions for the simulations and a study of the air circulation during the events is found in Morelli et al. (2007), Morelli and Casini (2008), Morelli et al. (2009). The Eta Model reproduced the evolution of upper and mod-level conditions in good agreement with AVHRR observations (Morelli, 2008, Morelli and Parmiggiani, 2009). Also, the simulated 10 m wind was well correlated with the observed extension of the polynya. In order to isolate the effect of the presence of the open water area on the structure of the atmospheric boundary layer and on the atmospheric circulation, further simulations were performed without the presence of the polynya, i.e. with its extent covered with sea ice. The numerical simulations show that the polynyas act to increase the speed of the air above them and generate strong heat fluxes that warm the air. The effects are found over and downwind the sea ice free area. Results from the Eta

  20. A Generalized Pyramid Matching Kernel for Human Action Recognition in Realistic Videos

    PubMed Central

    Zhu, Jun; Zhou, Quan; Zou, Weijia; Zhang, Rui; Zhang, Wenjun

    2013-01-01

    Human action recognition is an increasingly important research topic in the fields of video sensing, analysis and understanding. Caused by unconstrained sensing conditions, there exist large intra-class variations and inter-class ambiguities in realistic videos, which hinder the improvement of recognition performance for recent vision-based action recognition systems. In this paper, we propose a generalized pyramid matching kernel (GPMK) for recognizing human actions in realistic videos, based on a multi-channel “bag of words” representation constructed from local spatial-temporal features of video clips. As an extension to the spatial-temporal pyramid matching (STPM) kernel, the GPMK leverages heterogeneous visual cues in multiple feature descriptor types and spatial-temporal grid granularity levels, to build a valid similarity metric between two video clips for kernel-based classification. Instead of the predefined and fixed weights used in STPM, we present a simple, yet effective, method to compute adaptive channel weights of GPMK based on the kernel target alignment from training data. It incorporates prior knowledge and the data-driven information of different channels in a principled way. The experimental results on three challenging video datasets (i.e., Hollywood2, Youtube and HMDB51) validate the superiority of our GPMK w.r.t. the traditional STPM kernel for realistic human action recognition and outperform the state-of-the-art results in the literature. PMID:24284771

  1. Realistic prediction of solid pharmaceutical oxidation products by using a novel forced oxidation system.

    PubMed

    Ueyama, Eiji; Tamura, Kousuke; Mizukawa, Kousei; Kano, Kenji

    2014-04-01

    This study investigated a novel solid-state-based forced oxidation system to enable a realistic prediction of pharmaceutical product oxidation, a key consideration in drug development and manufacture. Polysorbate 80 and ferric(III) acetylacetonate were used as an organic hydroperoxide source and a transition metal catalyst, respectively. Homogeneous solutions of target compounds and these reagents were prepared in a mixed organic solvent. The organic solvent was removed rapidly under reduced pressure, and the oxidation of the resulting dried solid was investigated. Analysis of the oxidation products generated in test compounds by this proposed forced oxidation system using HPLC showed a high similarity with those generated during more prolonged naturalistic drug oxidation. The proposed system provided a better predictive performance in prediction of realistic oxidative degradants of the drugs tested than did other established methods. Another advantage of this system was that the generation of undesired products of hydrolysis, solvolysis, and thermolysis was prevented because efficient oxidation was achieved under mild conditions. The results of this study suggest that this system is suitable for a realistic prediction of oxidative degradation of solid pharmaceuticals. PMID:24497072

  2. Searching for the mechanisms of change: a protocol for a realist review of batterer treatment programmes

    PubMed Central

    Cheff, Rebecca; Finn, Debbie; Davloor, Whitney; O'Campo, Patricia

    2016-01-01

    Introduction Conflicting results reported by evaluations of typical batterer intervention programmes leave many judicial officials and policymakers uncertain about the best way to respond to domestic violence, and whether to recommend and fund these programmes. Traditional evaluations and systematic reviews tend to focus predominantly on whether the programmes ‘worked’ (eg, reduced recidivism) often at the exclusion of understanding for whom they may or may not have worked, under what circumstances, and why. Methods and analysis We are undertaking a realist review of the batterer treatment programme literature with the aim of addressing this gap. Keeping with the goals of realist review, our primary aims are to identify the theory that underlies these programmes, highlight the mechanisms that trigger changes in participant behaviour and finally explain why these programmes help some individuals reduce their use of violence and under what conditions they are effective or not effective. We begin by describing the process of perpetrator treatment, and by proposing an initial theoretical model of behaviour change that will be tested by our review. We then describe the criteria for inclusion of an evaluation into the review, the search strategy we will use to identify the studies, and the plan for data extraction and analysis. Ethics and dissemination The results of this review will be written up using the RAMESES Guidelines for Realist Synthesis, and disseminated through peer-reviewed publications aimed at the practitioner community as well as presented at community forums, and at violence against women conferences. Ethics approval was not needed. PMID:27053268

  3. Fidelity of reduced and realistic electron mass ratio multi-scale gyrokinetic simulations of tokamak discharges

    NASA Astrophysics Data System (ADS)

    Howard, N. T.; Holland, C.; White, A. E.; Greenwald, M.; Candy, J.

    2015-06-01

    The first study using multi-scale (coupled ITG/TEM/ETG) gyrokinetic simulations at both reduced and realistic electron mass ratios, μ = (mD/me).5 = 20.0, 40.0 and 60.0, has been performed on a standard, Alcator C-Mod, L-mode discharge. Ion-scale (kθρs  ∼  1.0) and multi-scale (up to kθρe  ∼  0.8) gyrokinetic simulations are compared at different simulated mass ratios to investigate the fidelity of reduced electron mass ratio, multi-scale simulation through direct comparison with realistic mass ratio, multi-scale simulation. Detailed description of both the numerical setup and the turbulent scales required to obtain meaningful coupled ITG/TEM/ETG simulation is presented. Significant high-k driven (TEM/ETG) heat flux is found to exist at scales of approximately kθρe  ∼  0.1 at all mass ratios but can only be obtained by simulation capturing turbulence up to kθρe  ∼  1.0. At slightly reduced mass ratio, μ = 40.0, qualitative agreement with realistic mass simulation can be obtained in the studied discharge, consistent with intuition obtained from linear stability analysis. However, realistic electron mass is required for any robust quantitative comparison with experimental heat fluxes for the condition studied, as significant differences are observed at even slightly reduced electron mass ratio. The details of this numerical study are presented to provide a basis for future studies utilizing coupled ITG/TEM/ETG gyrokinetic simulation.

  4. Intracochlear Drug Delivery Systems

    PubMed Central

    Borenstein, Jeffrey T.

    2011-01-01

    Introduction Advances in molecular biology and in the basic understanding of the mechanisms associated with sensorineural hearing loss and other diseases of the inner ear, are paving the way towards new approaches for treatments for millions of patients. However, the cochlea is a particularly challenging target for drug therapy, and new technologies will be required to provide safe and efficacious delivery of these compounds. Emerging delivery systems based on microfluidic technologies are showing promise as a means for direct intracochlear delivery. Ultimately, these systems may serve as a means for extended delivery of regenerative compounds to restore hearing in patients suffering from a host of auditory diseases. Areas covered in this review Recent progress in the development of drug delivery systems capable of direct intracochlear delivery is reviewed, including passive systems such as osmotic pumps, active microfluidic devices, and systems combined with currently available devices such as cochlear implants. The aim of this article is to provide a concise review of intracochlear drug delivery systems currently under development, and ultimately capable of being combined with emerging therapeutic compounds for the treatment of inner ear diseases. Expert Opinion Safe and efficacious treatment of auditory diseases will require the development of microscale delivery devices, capable of extended operation and direct application to the inner ear. These advances will require miniaturization and integration of multiple functions, including drug storage, delivery, power management and sensing, ultimately enabling closed-loop control and timed-sequence delivery devices for treatment of these diseases. PMID:21615213

  5. Precision robotic control of agricultural vehicles on realistic farm trajectories

    NASA Astrophysics Data System (ADS)

    Bell, Thomas

    High-precision "autofarming", or precise agricultural vehicle guidance, is rapidly becoming a reality thanks to increasing computing power and carrier-phase differential GPS ("CPDGPS") position and attitude sensors. Realistic farm trajectories will include not only rows but also arcs created by smoothly joining rows or path-planning algorithms, spirals for farming center-pivot irrigated fields, and curved trajectories dictated by nonlinear field boundaries. In addition, fields are often sloped, and accurate control may be required either on linear trajectories or on curved contours. A three-dimensional vehicle model which adapts to changing vehicle and ground conditions was created, and a low-order model for controller synthesis was extracted based on nominal conditions. The model was extended to include a towed implement. Experimentation showed that an extended Kalman filter could identify the vehicle's state in real-time. An approximation was derived for the additional positional uncertainty introduced by the noisy "lever-arm correction" necessary to translate the GPS position measurement at the roof antenna to the vehicle's control point on the ground; this approximation was then used to support the assertion that attitude measurement accuracy was as important to control point position measurement as the original position measurement accuracy at the GPS antenna. The low-order vehicle control model was transformed to polar coordinates for control on arcs and spirals. Experimental data showed that the tractor's control, point tracked an arc to within a -0.3 cm mean and a 3.4 cm standard deviation and a spiral to within a -0.2 cm mean and a 5.3 cm standard deviation. Cubic splines were used to describe curve trajectories, and a general expression for the time-rate-of-change of curve-related parameters was derived. Four vehicle control algorithms were derived for curve tracking: linear local-error control based on linearizing the vehicle about the curve's radius of

  6. Realistic Covariance Prediction for the Earth Science Constellation

    NASA Technical Reports Server (NTRS)

    Duncan, Matthew; Long, Anne

    2006-01-01

    Routine satellite operations for the Earth Science Constellation (ESC) include collision risk assessment between members of the constellation and other orbiting space objects. One component of the risk assessment process is computing the collision probability between two space objects. The collision probability is computed using Monte Carlo techniques as well as by numerically integrating relative state probability density functions. Each algorithm takes as inputs state vector and state vector uncertainty information for both objects. The state vector uncertainty information is expressed in terms of a covariance matrix. The collision probability computation is only as good as the inputs. Therefore, to obtain a collision calculation that is a useful decision-making metric, realistic covariance matrices must be used as inputs to the calculation. This paper describes the process used by the NASA/Goddard Space Flight Center's Earth Science Mission Operations Project to generate realistic covariance predictions for three of the Earth Science Constellation satellites: Aqua, Aura and Terra.

  7. Realistic Covariance Prediction For the Earth Science Constellations

    NASA Technical Reports Server (NTRS)

    Duncan, Matthew; Long, Anne

    2006-01-01

    Routine satellite operations for the Earth Science Constellations (ESC) include collision risk assessment between members of the constellations and other orbiting space objects. One component of the risk assessment process is computing the collision probability between two space objects. The collision probability is computed via Monte Carlo techniques as well as numerically integrating relative probability density functions. Each algorithm takes as inputs state vector and state vector uncertainty information for both objects. The state vector uncertainty information is expressed in terms of a covariance matrix. The collision probability computation is only as good as the inputs. Therefore, to obtain a collision calculation that is a useful decision-making metric, realistic covariance matrices must be used as inputs to the calculation. This paper describes the process used by NASA Goddard's Earth Science Mission Operations Project to generate realistic covariance predictions for three of the ESC satellites: Aqua, Aura, and Terra

  8. Realistic Parameters for the Description of Organic Metals

    NASA Astrophysics Data System (ADS)

    Dolfen, Andreas; Koch, Erik; Blum, Volker; Cano-Cortés, Laura; Merino, Jaime

    2009-03-01

    In molecular crystals correlation effects are often significant. For a non-perturbative description of the full Coulomb interaction we have therefore to resort to a model description in terms of generalized Hubbard models. The derivation of parameters for such models is crucial for realistic simulations. While hopping parameters are easily derived from density-functional theory (DFT) the Coulomb parameters pose a significant problem due to screening processes. We decompose their contributions into intra- and inter-molecular parts. The intra-molecularly screened Coulomb parameters are treated within DFT whereas the inter-molecular corrections are evaluated using classical electrostatics with DFT-derived polarizabilities and the distributed-dipole approach in combination with a Ewald summation. Even for simple lattices of polarizable point dipoles we find intriguing screening phenomena. As realistic applications we discuss the one- and two-dimensional organic metals TTF-TCNQ and θ-(BEDT-TTF)2I3.

  9. Realistic fetus skin color processing for ultrasound volume rendering

    NASA Astrophysics Data System (ADS)

    Kim, Yun-Tae; Kim, Kyuhong; Park, Sung-Chan; Kang, Jooyoung; Kim, Jung-Ho

    2014-01-01

    This paper proposes realistic fetus skin color processing using a 2D color map and a tone mapping function (TMF) for ultrasound volume rendering. The contributions of this paper are a 2D color map generated through a gamut model of skin color and a TMF that depends on the lighting position. First, the gamut model of fetus skin color is calculated by color distribution of baby images. The 2D color map is created using a gamut model for tone mapping of ray casting. For the translucent effect, a 2D color map in which lightness is inverted is generated. Second, to enhance the contrast of rendered images, the luminance, color, and tone curve TMF parameters are changed using 2D Gaussian function that depends on the lighting position. The experimental results demonstrate that the proposed method achieves better realistic skin color reproduction than the conventional method.

  10. Automatic Perceptual Color Map Generation for Realistic Volume Visualization

    PubMed Central

    Silverstein, Jonathan C.; Parsad, Nigel M.; Tsirline, Victor

    2008-01-01

    Advances in computed tomography imaging technology and inexpensive high performance computer graphics hardware are making high-resolution, full color (24-bit) volume visualizations commonplace. However, many of the color maps used in volume rendering provide questionable value in knowledge representation and are non-perceptual thus biasing data analysis or even obscuring information. These drawbacks, coupled with our need for realistic anatomical volume rendering for teaching and surgical planning, has motivated us to explore the auto-generation of color maps that combine natural colorization with the perceptual discriminating capacity of grayscale. As evidenced by the examples shown that have been created by the algorithm described, the merging of perceptually accurate and realistically colorized virtual anatomy appears to insightfully interpret and impartially enhance volume rendered patient data. PMID:18430609

  11. Blend Shape Interpolation and FACS for Realistic Avatar

    NASA Astrophysics Data System (ADS)

    Alkawaz, Mohammed Hazim; Mohamad, Dzulkifli; Basori, Ahmad Hoirul; Saba, Tanzila

    2015-03-01

    The quest of developing realistic facial animation is ever-growing. The emergence of sophisticated algorithms, new graphical user interfaces, laser scans and advanced 3D tools imparted further impetus towards the rapid advancement of complex virtual human facial model. Face-to-face communication being the most natural way of human interaction, the facial animation systems became more attractive in the information technology era for sundry applications. The production of computer-animated movies using synthetic actors are still challenging issues. Proposed facial expression carries the signature of happiness, sadness, angry or cheerful, etc. The mood of a particular person in the midst of a large group can immediately be identified via very subtle changes in facial expressions. Facial expressions being very complex as well as important nonverbal communication channel are tricky to synthesize realistically using computer graphics. Computer synthesis of practical facial expressions must deal with the geometric representation of the human face and the control of the facial animation. We developed a new approach by integrating blend shape interpolation (BSI) and facial action coding system (FACS) to create a realistic and expressive computer facial animation design. The BSI is used to generate the natural face while the FACS is employed to reflect the exact facial muscle movements for four basic natural emotional expressions such as angry, happy, sad and fear with high fidelity. The results in perceiving the realistic facial expression for virtual human emotions based on facial skin color and texture may contribute towards the development of virtual reality and game environment of computer aided graphics animation systems.

  12. An Argument Against the Realistic Interpretation of the Wave Function

    NASA Astrophysics Data System (ADS)

    Rovelli, Carlo

    2016-07-01

    Testable predictions of quantum mechanics are invariant under time reversal. But the evolution of the quantum state in time is not so, neither in the collapse nor in the no-collapse interpretations of the theory. This is a fact that challenges any realistic interpretation of the quantum state. On the other hand, this fact raises no difficulty if we interpret the quantum state as a mere calculation device, bookkeeping past real quantum events.

  13. Realistic localizer courses for aircraft instrument landing simulators

    NASA Technical Reports Server (NTRS)

    Murphy, T. A.

    1984-01-01

    The realistic instrument landing simulator (ILS) course structures for use in aircraft simulators are described. Software developed for data conversion and translation of ILS course structure measurements and calcomp plots of the courses provided are described. A method of implementing the ILS course structure data in existing aircraft simulators is outlined. A cockpit used in the lab to review the digitized ILS course structures is displayed.

  14. MRXCAT: Realistic numerical phantoms for cardiovascular magnetic resonance

    PubMed Central

    2014-01-01

    Background Computer simulations are important for validating novel image acquisition and reconstruction strategies. In cardiovascular magnetic resonance (CMR), numerical simulations need to combine anatomical information and the effects of cardiac and/or respiratory motion. To this end, a framework for realistic CMR simulations is proposed and its use for image reconstruction from undersampled data is demonstrated. Methods The extended Cardiac-Torso (XCAT) anatomical phantom framework with various motion options was used as a basis for the numerical phantoms. Different tissue, dynamic contrast and signal models, multiple receiver coils and noise are simulated. Arbitrary trajectories and undersampled acquisition can be selected. The utility of the framework is demonstrated for accelerated cine and first-pass myocardial perfusion imaging using k-t PCA and k-t SPARSE. Results MRXCAT phantoms allow for realistic simulation of CMR including optional cardiac and respiratory motion. Example reconstructions from simulated undersampled k-t parallel imaging demonstrate the feasibility of simulated acquisition and reconstruction using the presented framework. Myocardial blood flow assessment from simulated myocardial perfusion images highlights the suitability of MRXCAT for quantitative post-processing simulation. Conclusion The proposed MRXCAT phantom framework enables versatile and realistic simulations of CMR including breathhold and free-breathing acquisitions. PMID:25204441

  15. Near-realistic mobile exergames with wireless wearable sensors.

    PubMed

    Mortazavi, Bobak; Nyamathi, Suneil; Lee, Sunghoon Ivan; Wilkerson, Thomas; Ghasemzadeh, Hassan; Sarrafzadeh, Majid

    2014-03-01

    Exergaming is expanding as an option for sedentary behavior in childhood/adult obesity and for extra exercise for gamers. This paper presents the development process for a mobile active sports exergame with near-realistic motions through the usage of body-wearable sensors. The process begins by collecting a dataset specifically targeted to mapping real-world activities directly to the games, then, developing the recognition system in a fashion to produce an enjoyable game. The classification algorithm in this paper has precision and recall of 77% and 77% respectively, compared with 40% and 19% precision and recall on current activity monitoring algorithms intended for general daily living activities. Aside from classification, the user experience must be strong enough to be a successful system for adoption. Indeed, fast and intense activities as well as competitive, multiplayer environments make for a successful, enjoyable exergame. This enjoyment is evaluated through a 30 person user study. Multiple aspects of the exergaming user experience trials have been merged into a comprehensive survey, called ExerSurvey. All but one user thought the motions in the game were realistic and difficult to cheat. Ultimately, a game with near-realistic motions was shown to be an enjoyable, active video exergame for any environment. PMID:24608050

  16. Relating realist metatheory to issues of gender and mental health.

    PubMed

    Bergin, M; Wells, John S G; Owen, Sara

    2010-06-01

    This paper seeks to advance the debate that considers critical realism as an alternative approach for understanding gender and mental health and its relatedness to mental health research and practice. The knowledge base of how 'sex' and 'gender' affect mental health and illness is expanding. However, the way we conceptualize gender is significant and challenging as quite often our ability to think about 'gender' as independent of 'sex' is not common. The influences and interplay of how sex (biological) and gender (social) affect mental health and illness requires consideration. Critical realism suggests a shared ontology and epistemology for the natural and social sciences. While much of the debate surrounding gender is guided within a constructivist discourse, an exploration of the concept 'gender' is reflected on and some key realist propositions are considered for mental health research and practice. This is achieved through the works of some key realist theorists. Critical realism offers potential for research and practice in relation to gender and mental health because it facilitates changes in our understanding, while simultaneously, not discarding that which is already known. In so doing, it allows the biological (sex) and social (gender) domains of knowledge for mental health and illness to coexist, without either being reduced to or defined by the other. Arguably, greater depth and explanations for gender and mental health issues are presented within a realist metatheory. PMID:20584241

  17. An anatomically realistic temperature phantom for radiofrequency heating measurements

    PubMed Central

    Graedel, Nadine N.; Polimeni, Jonathan R.; Guerin, Bastien; Gagoski, Borjan; Wald, Lawrence L.

    2014-01-01

    Purpose An anthropomorphic phantom with realistic electrical properties allows for a more accurate reproduction of tissue current patterns during excitation. A temperature map can then probe the worst-case heating expected in the un-perfused case. We describe an anatomically realistic human head phantom that allows rapid 3D temperature mapping at 7 T. Methods The phantom was based on hand-labeled anatomical imaging data and consists of four compartments matching the corresponding human tissues in geometry and electrical properties. The increases in temperature resulting from radiofrequency excitation were measured with MR thermometry using a temperature sensitive contrast agent (TmDOTMA−) validated by direct fiber optic temperature measurements. Results Acquisition of 3D temperature maps of the full phantom with a temperature accuracy better than 0.1°C was achieved with an isotropic resolution of 5 mm and acquisition times of 2–4 minutes. Conclusion Our results demonstrate the feasibility of constructing anatomically realistic phantoms with complex geometries incorporating the ability to measure accurate temperature maps in the phantom. The anthropomorphic temperature phantom is expected to provide a useful tool for the evaluation of the heating effects of both conventional and parallel transmit pulses and help validate electromagnetic and temperature simulations. PMID:24549755

  18. Depigmented Skin and Phantom Color Measurements for Realistic Prostheses

    PubMed Central

    Tanner, Paul; Leachman, Sancy; Boucher, Kenneth; Ozçelik, Tunçer Burak

    2013-01-01

    Purpose The purpose of this study was to test the hypothesis that regardless of human skin phototype, areas of depigmented skin, as seen in vitiligo, are optically indistinguishable among skin phototypes. The average of the depigmented skin measurements can be used to develop the base color of realistic prostheses. Methods and Materials Data from 20 of 32 recruited vitiligo study participants. Diffuse reflectance spectroscopy measurements were made from depigmented skin and adjacent pigmented skin, then compared to 66 pigmented polydimethylsiloxane phantoms to determine pigment concentrations in turbid media for making realistic facial prostheses. Results The Area Under spectral intensity Curve (AUC) was calculated for average spectroscopy measurements of pigmented sites in relation to skin phototype (p=0.0505) and depigmented skin in relation to skin phototype (p=0.59). No significant relationship exists between skin phototypes and depigmented skin spectroscopy measurements. The average of the depigmented skin measurements (AUC 19,129) was the closest match to phantom 6.4 (AUC 19,162) Conclusions Areas of depigmented skin are visibly indistinguishable per skin phototype, yet spectrometry shows that depigmented skin measurements varied and were unrelated to skin phototype. Possible sources of optical variation of depigmented skin include age, body site, blood flow, quantity/quality of collagen, and other chromophores. The average of all depigmented skin measurements can be used to derive the pigment composition and concentration for realistic facial prostheses. PMID:23750920

  19. Realistic terrain visualization based on 3D virtual world technology

    NASA Astrophysics Data System (ADS)

    Huang, Fengru; Lin, Hui; Chen, Bin; Xiao, Cai

    2010-11-01

    The rapid advances in information technologies, e.g., network, graphics processing, and virtual world, have provided challenges and opportunities for new capabilities in information systems, Internet applications, and virtual geographic environments, especially geographic visualization and collaboration. In order to achieve meaningful geographic capabilities, we need to explore and understand how these technologies can be used to construct virtual geographic environments to help to engage geographic research. The generation of three-dimensional (3D) terrain plays an important part in geographical visualization, computer simulation, and virtual geographic environment applications. The paper introduces concepts and technologies of virtual worlds and virtual geographic environments, explores integration of realistic terrain and other geographic objects and phenomena of natural geographic environment based on SL/OpenSim virtual world technologies. Realistic 3D terrain visualization is a foundation of construction of a mirror world or a sand box model of the earth landscape and geographic environment. The capabilities of interaction and collaboration on geographic information are discussed as well. Further virtual geographic applications can be developed based on the foundation work of realistic terrain visualization in virtual environments.

  20. Realistic terrain visualization based on 3D virtual world technology

    NASA Astrophysics Data System (ADS)

    Huang, Fengru; Lin, Hui; Chen, Bin; Xiao, Cai

    2009-09-01

    The rapid advances in information technologies, e.g., network, graphics processing, and virtual world, have provided challenges and opportunities for new capabilities in information systems, Internet applications, and virtual geographic environments, especially geographic visualization and collaboration. In order to achieve meaningful geographic capabilities, we need to explore and understand how these technologies can be used to construct virtual geographic environments to help to engage geographic research. The generation of three-dimensional (3D) terrain plays an important part in geographical visualization, computer simulation, and virtual geographic environment applications. The paper introduces concepts and technologies of virtual worlds and virtual geographic environments, explores integration of realistic terrain and other geographic objects and phenomena of natural geographic environment based on SL/OpenSim virtual world technologies. Realistic 3D terrain visualization is a foundation of construction of a mirror world or a sand box model of the earth landscape and geographic environment. The capabilities of interaction and collaboration on geographic information are discussed as well. Further virtual geographic applications can be developed based on the foundation work of realistic terrain visualization in virtual environments.

  1. Exposure Render: An Interactive Photo-Realistic Volume Rendering Framework

    PubMed Central

    Kroes, Thomas; Post, Frits H.; Botha, Charl P.

    2012-01-01

    The field of volume visualization has undergone rapid development during the past years, both due to advances in suitable computing hardware and due to the increasing availability of large volume datasets. Recent work has focused on increasing the visual realism in Direct Volume Rendering (DVR) by integrating a number of visually plausible but often effect-specific rendering techniques, for instance modeling of light occlusion and depth of field. Besides yielding more attractive renderings, especially the more realistic lighting has a positive effect on perceptual tasks. Although these new rendering techniques yield impressive results, they exhibit limitations in terms of their exibility and their performance. Monte Carlo ray tracing (MCRT), coupled with physically based light transport, is the de-facto standard for synthesizing highly realistic images in the graphics domain, although usually not from volumetric data. Due to the stochastic sampling of MCRT algorithms, numerous effects can be achieved in a relatively straight-forward fashion. For this reason, we have developed a practical framework that applies MCRT techniques also to direct volume rendering (DVR). With this work, we demonstrate that a host of realistic effects, including physically based lighting, can be simulated in a generic and flexible fashion, leading to interactive DVR with improved realism. In the hope that this improved approach to DVR will see more use in practice, we have made available our framework under a permissive open source license. PMID:22768292

  2. Transdermal delivery of contraceptives.

    PubMed

    Friend, D R

    1990-01-01

    Contraceptive agents are administered to the body through a variety of routes. Research has recently been directed at examining the transdermal route for systemic delivery of contraceptive agents, including estrogens and progestins. The transdermal route has several potential advantages over the other routes of administration: (1) improved compliance, (2) once-weekly administration, (3) delivery is easily terminated, and (4) some side effects can be alleviated based on more constant delivery rates. This article reviews the permeability of skin toward contraceptive steroids and how skin permeability is evaluated. The metabolism of contraceptive steroids is also considered. Transdermal delivery systems used to deliver contraceptives are presented, followed by a detailed discussion of several delivery systems for specific contraceptive agents such as levonorgestrel and estradiol. The potential problem of skin irritation is presented as it relates to transdermal contraceptive delivery systems, all of which will be worn chronically. PMID:2272099

  3. Antibiotic delivery by nanobioceramics.

    PubMed

    Kumar, Ts Sampath; Madhumathi, K

    2016-08-01

    The role of nanotechnology has evinced remarkable interest in the field of drug delivery. Bioceramics are inorganic biomaterials which are frequently used as bone substitutes. They have been explored in drug delivery as carriers for antibiotics, anti-osteoporotic drugs and anticancer drugs. Bioceramic nanoparticles are excellent alternatives to polymers due to their bioactivity, pH and temperature stability, multifunctionality, biocompatibility and tunable biodegradability. The use of bioceramics for local drug delivery in the field of orthopedics offer an efficient, safe mode of drug delivery directly to the surgical site thereby overcoming the limitations of systemic drug delivery. This review focuses on the development and applications of various nanobioceramics employed as drug delivery systems for the treatment of bone infections. PMID:27444496

  4. Realistic Simulation for Body Area and Body-To-Body Networks

    PubMed Central

    Alam, Muhammad Mahtab; Ben Hamida, Elyes; Ben Arbia, Dhafer; Maman, Mickael; Mani, Francesco; Denis, Benoit; D’Errico, Raffaele

    2016-01-01

    In this paper, we present an accurate and realistic simulation for body area networks (BAN) and body-to-body networks (BBN) using deterministic and semi-deterministic approaches. First, in the semi-deterministic approach, a real-time measurement campaign is performed, which is further characterized through statistical analysis. It is able to generate link-correlated and time-varying realistic traces (i.e., with consistent mobility patterns) for on-body and body-to-body shadowing and fading, including body orientations and rotations, by means of stochastic channel models. The full deterministic approach is particularly targeted to enhance IEEE 802.15.6 proposed channel models by introducing space and time variations (i.e., dynamic distances) through biomechanical modeling. In addition, it helps to accurately model the radio link by identifying the link types and corresponding path loss factors for line of sight (LOS) and non-line of sight (NLOS). This approach is particularly important for links that vary over time due to mobility. It is also important to add that the communication and protocol stack, including the physical (PHY), medium access control (MAC) and networking models, is developed for BAN and BBN, and the IEEE 802.15.6 compliance standard is provided as a benchmark for future research works of the community. Finally, the two approaches are compared in terms of the successful packet delivery ratio, packet delay and energy efficiency. The results show that the semi-deterministic approach is the best option; however, for the diversity of the mobility patterns and scenarios applicable, biomechanical modeling and the deterministic approach are better choices. PMID:27104537

  5. Realistic Simulation for Body Area and Body-To-Body Networks.

    PubMed

    Alam, Muhammad Mahtab; Ben Hamida, Elyes; Ben Arbia, Dhafer; Maman, Mickael; Mani, Francesco; Denis, Benoit; D'Errico, Raffaele

    2016-01-01

    In this paper, we present an accurate and realistic simulation for body area networks (BAN) and body-to-body networks (BBN) using deterministic and semi-deterministic approaches. First, in the semi-deterministic approach, a real-time measurement campaign is performed, which is further characterized through statistical analysis. It is able to generate link-correlated and time-varying realistic traces (i.e., with consistent mobility patterns) for on-body and body-to-body shadowing and fading, including body orientations and rotations, by means of stochastic channel models. The full deterministic approach is particularly targeted to enhance IEEE 802.15.6 proposed channel models by introducing space and time variations (i.e., dynamic distances) through biomechanical modeling. In addition, it helps to accurately model the radio link by identifying the link types and corresponding path loss factors for line of sight (LOS) and non-line of sight (NLOS). This approach is particularly important for links that vary over time due to mobility. It is also important to add that the communication and protocol stack, including the physical (PHY), medium access control (MAC) and networking models, is developed for BAN and BBN, and the IEEE 802.15.6 compliance standard is provided as a benchmark for future research works of the community. Finally, the two approaches are compared in terms of the successful packet delivery ratio, packet delay and energy efficiency. The results show that the semi-deterministic approach is the best option; however, for the diversity of the mobility patterns and scenarios applicable, biomechanical modeling and the deterministic approach are better choices. PMID:27104537

  6. Systemic gene delivery following intravenous administration of AAV9 to fetal and neonatal mice and late-gestation nonhuman primates.

    PubMed

    Mattar, Citra N; Wong, Andrew M S; Hoefer, Klemens; Alonso-Ferrero, Maria E; Buckley, Suzanne M K; Howe, Steven J; Cooper, Jonathan D; Waddington, Simon N; Chan, Jerry K Y; Rahim, Ahad A

    2015-09-01

    Several acute monogenic diseases affect multiple body systems, causing death in childhood. The development of novel therapies for such conditions is challenging. However, improvements in gene delivery technology mean that gene therapy has the potential to treat such disorders. We evaluated the ability of the AAV9 vector to mediate systemic gene delivery after intravenous administration to perinatal mice and late-gestation nonhuman primates (NHPs). Titer-matched single-stranded (ss) and self-complementary (sc) AAV9 carrying the green fluorescent protein (GFP) reporter gene were intravenously administered to fetal and neonatal mice, with noninjected age-matched mice used as the control. Extensive GFP expression was observed in organs throughout the body, with the epithelial and muscle cells being particularly well transduced. ssAAV9 carrying the WPRE sequence mediated significantly more gene expression than its sc counterpart, which lacked the woodchuck hepatitis virus posttranscriptional regulatory element (WPRE) sequence. To examine a realistic scale-up to larger models or potentially patients for such an approach, AAV9 was intravenously administered to late-gestation NHPs by using a clinically relevant protocol. Widespread systemic gene expression was measured throughout the body, with cellular tropisms similar to those observed in the mouse studies and no observable adverse events. This study confirms that AAV9 can safely mediate systemic gene delivery in small and large animal models and supports its potential use in clinical systemic gene therapy protocols. PMID:26062602

  7. Computer simulations of realistic microstructures: Implications for simulation-based materials design

    NASA Astrophysics Data System (ADS)

    Singh, Harpreet

    The conventional route of materials development typically involves fabrication of numerous batches of specimens having a range of different microstructures generated via variations of process parameters and measurements of relevant properties of these microstructures to identify the combination of processing conditions that yield the material having desired properties. Clearly, such a trial and error based materials development methodology is expensive, time consuming, and inefficient. Consequently, it is of interest to explore alternate strategies that can lead to a decrease in the cost and time required for development of advanced materials such as composites. Availability of powerful and inexpensive computational power and progress in computational materials science permits advancement of modeling and simulations assisted materials design methodology that may require fewer experiments, and therefore, lower cost and time for materials development. The key facets of such a technology would be computational tools for (i) creating models to generate computer simulated realistic microstructures; (ii) capturing the process-microstructure relationship using these models; and (iii) implementation of simulated microstructures in the computational models for materials behavior. Therefore, development of a general and flexible methodology for simulations of realistic microstructures is crucial for the development of simulations based materials design and development technology. Accordingly, this research concerns development of such a methodology for simulations of realistic microstructures based on experimental quantitative stereological data on few microstructures that can capture relevant details of microstructural geometry (including spatial clustering and second phase particle orientations) and its variations with process parameters in terms of a set of simulation parameters. The interpolation and extrapolation of the simulation parameters can then permit generation

  8. Processing of the GALILEOTM fuel rod code model uncertainties within the AREVA LWR realistic thermal-mechanical analysis methodology

    NASA Astrophysics Data System (ADS)

    Mailhe, P.; Barbier, B.; Garnier, Ch.; Landskron, H.; Sedlacek, R.; Arimescu, I.; Smith, M.; Bellanger, Ph.

    2014-06-01

    The availability of reliable tools and associated methodology able to accurately predict the LWR fuel behavior in all conditions is of great importance for safe and economic fuel usage. For that purpose, AREVA has developed its new global fuel rod performance code GALILEOTM along with its associated realistic thermal-mechanical analysis methodology. This realistic methodology is based on a Monte Carlo type random sampling of all relevant input variables. After having outlined the AREVA realistic methodology, this paper will be focused on the GALILEOTM code benchmarking process on its extended experimental database and the GALILEOTM model uncertainties assessment. The propagation of these model uncertainties through the AREVA realistic methodology is also presented. This GALILEOTM model uncertainties processing is of the utmost importance for accurate fuel design margin evaluation as illustrated on some application examples. With the submittal of Topical Report for GALILEOTM to the U.S. NRC in 2013, GALILEOTM and its methodology are on the way to be industrially used in a wide range of irradiation conditions.

  9. Drug delivery systems.

    PubMed

    Robinson, D H; Mauger, J W

    1991-10-01

    New and emerging drug delivery systems for traditional drugs and the products of biotechnology are discussed, and the role of the pharmacist in ensuring the appropriate use of these systems is outlined. Advantages of advanced drug delivery systems over traditional systems are the ability to deliver a drug more selectively to a specific site; easier, more accurate, less frequent dosing; decreased variability in systemic drug concentrations; absorption that is more consistent with the site and mechanism of action; and reductions in toxic metabolites. Four basic strategies govern the mechanisms of advanced drug delivery: physical, chemical, biological, and mechanical. Oral drug delivery systems use natural and synthetic polymers to deliver the product to a specific region in the gastrointestinal tract in a timely manner that minimizes adverse effects and increases drug efficacy. Innovations in injectable and implantable delivery systems include emulsions, particulate delivery systems, micromolecular products and macromolecular drug adducts, and enzymatic-controlled delivery. Options for noninvasive drug delivery include the transdermal, respiratory, intranasal, ophthalmic, lymphatic, rectal, intravaginal, and intrauterine routes as well as topical application. Rapid growth is projected in the drug delivery systems market worldwide in the next five years. Genetic engineering has mandated the development of new strategies to deliver biotechnologically derived protein and peptide drugs and chemoimmunoconjugates. The role of the pharmacist in the era of advanced drug delivery systems will be broad based, including administering drugs, compounding, calculating dosages based on pharmacokinetic and pharmacodynamic monitoring, counseling, and research. The advent of advanced drug delivery systems offers pharmacists a new opportunity to assume an active role in patient care. PMID:1772110

  10. Validation of Building Energy Modeling Tools Under Idealized and Realistic Conditions

    SciTech Connect

    Ryan, Emily M.; Sanquist, Thomas F.

    2012-04-02

    Building energy models provide valuable insight into the energy use of commercial and residential buildings based on the building architecture, materials and thermal loads. They are used in the design of new buildings and the retrofitting to increase the efficiency of older buildings. The accuracy of these models is crucial to reducing the energy use of the United States and building a sustainable energy future. In addition to the architecture and thermal loads of a building, building energy models also must account for the effects of the building's occupants on the energy use of the building. Traditionally simple schedule based methods have been used to account for the effects of the occupants. However, newer research has shown that these methods often result in large differences between the modeled and actual energy use of buildings. In this paper we discuss building energy models and their accuracy in predicting building energy use. In particular we focus on the different types of validation methods which have been used to investigate the accuracy of building energy models and how they account for (or do not account for) the effects of occupants. We also review some of the newer work on stochastic methods for estimating the effects of occupants on building energy use and discuss the improvements necessary to increase the accuracy of building energy models.

  11. Best Alternatives to Cronbach's Alpha Reliability in Realistic Conditions: Congeneric and Asymmetrical Measurements

    PubMed Central

    Trizano-Hermosilla, Italo; Alvarado, Jesús M.

    2016-01-01

    The Cronbach's alpha is the most widely used method for estimating internal consistency reliability. This procedure has proved very resistant to the passage of time, even if its limitations are well documented and although there are better options as omega coefficient or the different versions of glb, with obvious advantages especially for applied research in which the ítems differ in quality or have skewed distributions. In this paper, using Monte Carlo simulation, the performance of these reliability coefficients under a one-dimensional model is evaluated in terms of skewness and no tau-equivalence. The results show that omega coefficient is always better choice than alpha and in the presence of skew items is preferable to use omega and glb coefficients even in small samples. PMID:27303333

  12. Stability and Aggregation Kinetics of Titania Nanomaterials under Environmentally Realistic Conditions.

    PubMed

    Raza, Ghulam; Amjad, Muhammad; Kaur, Inder; Wen, Dongsheng

    2016-08-16

    Nanoparticle morphology is expected to play a significant role in the stability, aggregation behavior, and ultimate fate of engineered nanomaterials in natural aquatic environments. The aggregation kinetics of ellipsoidal and spherical titanium dioxide (TiO2) nanoparticles (NPs) under different surfactant loadings, pH values, and ionic strengths were investigated in this study. The stability results revealed that alteration of surface charge was the stability determining factor. Among five different surfactants investigated, sodium citrate and Suwannee river fulvic acid (SRFA) were the most effective stabilizers. It was observed that both types of NPs were more stable in monovalent salts (NaCl and NaNO3) as compared with divalent salts (Ca(NO3)2 and CaCl2). The aggregation of spherical TiO2 NPs demonstrated a strong dependency on the ionic strength regardless of the presence of mono or divalent salts; while the ellipsoids exhibited a lower dependency on the ionic strength but was more stable. This work acts as a benchmark study toward understanding the ultimate fate of stabilized NPs in natural environments that are rich in Ca(CO3)2, NaNO3, NaCl, and CaCl2 along with natural organic matters. PMID:27228447

  13. Cesarean Delivery for a Life-threatening Preterm Placental Abruption

    PubMed Central

    Okafor, II; Ugwu, EO

    2015-01-01

    Placental abruption is one of the major life-threatening obstetric conditions. The fetomaternal outcome of a severe placental abruption depends largely on prompt maternal resuscitation and delivery. A case of severe preterm placental abruption with intrauterine fetal death. Following a failed induction of labor with a deteriorating maternal condition despite resuscitation, emergency cesarean delivery was offered with good maternal outcome. Cesarean delivery could avert further disease progression and possible maternal death in cases of severe preterm placental abruption where vaginal delivery is not imminent. However, further studies are necessary before this could be recommended for routine clinical practice. PMID:27057388

  14. Ocular drug delivery.

    PubMed

    Gaudana, Ripal; Ananthula, Hari Krishna; Parenky, Ashwin; Mitra, Ashim K

    2010-09-01

    Ocular drug delivery has been a major challenge to pharmacologists and drug delivery scientists due to its unique anatomy and physiology. Static barriers (different layers of cornea, sclera, and retina including blood aqueous and blood-retinal barriers), dynamic barriers (choroidal and conjunctival blood flow, lymphatic clearance, and tear dilution), and efflux pumps in conjunction pose a significant challenge for delivery of a drug alone or in a dosage form, especially to the posterior segment. Identification of influx transporters on various ocular tissues and designing a transporter-targeted delivery of a parent drug has gathered momentum in recent years. Parallelly, colloidal dosage forms such as nanoparticles, nanomicelles, liposomes, and microemulsions have been widely explored to overcome various static and dynamic barriers. Novel drug delivery strategies such as bioadhesive gels and fibrin sealant-based approaches were developed to sustain drug levels at the target site. Designing noninvasive sustained drug delivery systems and exploring the feasibility of topical application to deliver drugs to the posterior segment may drastically improve drug delivery in the years to come. Current developments in the field of ophthalmic drug delivery promise a significant improvement in overcoming the challenges posed by various anterior and posterior segment diseases. PMID:20437123

  15. A full potential flow analysis with realistic wake influence for helicopter rotor airload prediction

    NASA Technical Reports Server (NTRS)

    Egolf, T. Alan; Sparks, S. Patrick

    1987-01-01

    A 3-D, quasi-steady, full potential flow solver was adapted to include realistic wake influence for the aerodynamic analysis of helicopter rotors. The method is based on a finite difference solution of the full potential equation, using an inner and outer domain procedure for the blade flowfield to accommodate wake effects. The nonlinear flow is computed in the inner domain region using a finite difference solution method. The wake is modeled by a vortex lattice using prescribed geometry techniques to allow for the inclusion of realistic rotor wakes. The key feature of the analysis is that vortices contained within the finite difference mesh (inner domain) were treated with a vortex embedding technique while the influence of the remaining portion of the wake (in the outer domain) is impressed as a boundary condition on the outer surface of the finite difference mesh. The solution procedure couples the wake influence with the inner domain solution in a consistent and efficient solution process. The method has been applied to both hover and forward flight conditions. Correlation with subsonic and transonic hover airload data is shown which demonstrates the merits of the approach.

  16. Targeting the brain: advances in drug delivery.

    PubMed

    Blumling Iii, James P; Silva, Gabriel A

    2012-09-01

    The blood-brain barrier (BBB) represents a significant obstacle for drug delivery to the brain. Many therapeutics with potential for treating neurological conditions prove incompatible with intravenous delivery simply because of this barrier. Rather than modifying drugs to penetrate the BBB directly, it has proven more efficacious to either physically bypass the barrier or to use specialized delivery vehicles that circumvent BBB regulatory mechanisms. Controlled-release intracranial polymer implants and particle injections are the clinical state of the art with regard to localized delivery, although these approaches can impose significant surgical risks. Focused ultrasound provides a non-invasive alternative that may prove more desirable for acute treatment of brain tumors and other conditions requiring local tissue necrosis. For targeting the brain as a whole, cell-penetrating peptides (CPPs) and molecular trojan horses (MTHs) have demonstrated particular ability as delivery molecules and will likely see increased application. CPPs are not brain specific but offer the potential for efficient traversal of the BBB, and tandem systems with targeting molecules may produce extremely effective brain drug delivery tools. Molecular trojan horses utilize receptor-mediated transcytosis to transport cargo and are thus limited by the quantity of relevant receptors; however, they can be very selective for the BBB endothelium and have shown promise in gene therapy. PMID:23016646

  17. Large-System Transformation in Health Care: A Realist Review

    PubMed Central

    Best, Allan; Greenhalgh, Trisha; Lewis, Steven; Saul, Jessie E; Carroll, Simon; Bitz, Jennifer

    2012-01-01

    Context An evidence base that addresses issues of complexity and context is urgently needed for large-system transformation (LST) and health care reform. Fundamental conceptual and methodological challenges also must be addressed. The Saskatchewan Ministry of Health in Canada requested a six-month synthesis project to guide four major policy development and strategy initiatives focused on patient- and family-centered care, primary health care renewal, quality improvement, and surgical wait lists. The aims of the review were to analyze examples of successful and less successful transformation initiatives, to synthesize knowledge of the underlying mechanisms, to clarify the role of government, and to outline options for evaluation. Methods We used realist review, whose working assumption is that a particular intervention triggers particular mechanisms of change. Mechanisms may be more or less effective in producing their intended outcomes, depending on their interaction with various contextual factors. We explain the variations in outcome as the interplay between context and mechanisms. We nested this analytic approach in a macro framing of complex adaptive systems (CAS). Findings Our rapid realist review identified five “simple rules” of LST that were likely to enhance the success of the target initiatives: (1) blend designated leadership with distributed leadership; (2) establish feedback loops; (3) attend to history; (4) engage physicians; and (5) include patients and families. These principles play out differently in different contexts affecting human behavior (and thereby contributing to change) through a wide range of different mechanisms. Conclusions Realist review methodology can be applied in combination with a complex system lens on published literature to produce a knowledge synthesis that informs a prospective change effort in large-system transformation. A collaborative process engaging both research producers and research users contributes to local

  18. Structure of the singularity inside a realistic rotating black hole

    NASA Astrophysics Data System (ADS)

    Ori, Amos

    1992-04-01

    The structure and results of an analysis of the asymptotic behavior of nonlinear, asymmetric, metric perturbations near the Cauchy horizon inside a Kerr black hole are presented. This analysis suggests that metric perturbations, to all orders in the perturbation expansion, are finite and small at the Cauchy horizon, even though their gradients (and the curvature) diverge there. Accordingly, objects which fall into a realistic rotating blackhole a longtime after the collapse will not be crushed by a tidal gravitational deformations as they approach the curvature singularity.

  19. A continuous family of realistic Susy SU(5) GUTs

    NASA Astrophysics Data System (ADS)

    Bajc, Borut

    2016-06-01

    It is shown that the minimal renormalizable supersymmetric SU(5) is still realistic providing the supersymmetric scale is at least few tens of TeV or large R-parity violating terms are considered. In the first case the vacuum is metastable, and different consistency constraints can give a bounded allowed region in the tan β - msusy plane. In the second case the mass eigenstate electron (down quark) is a linear combination of the original electron (down quark) and Higgsino (heavy colour triplet), and the mass ratio of bino and wino is determined. Both limits lead to light gravitino dark matter.

  20. The KM phase in semi-realistic heterotic orbifold models

    SciTech Connect

    Giedt, Joel

    2000-07-05

    In string-inspired semi-realistic heterotic orbifolds models with an anomalous U(1){sub X},a nonzero Kobayashi-Masakawa (KM) phase is shown to arise generically from the expectation values of complex scalar fields, which appear in nonrenormalizable quark mass couplings. Modular covariant nonrenormalizable superpotential couplings are constructed. A toy Z{sub 3} orbifold model is analyzed in some detail. Modular symmetries and orbifold selection rules are taken into account and do not lead to a cancellation of the KM phase. We also discuss attempts to obtain the KM phase solely from renormalizable interactions.

  1. Analytical theory of extraordinary optical transmission through realistic metallic screens.

    PubMed

    Delgado, V; Marqués, R; Jelinek, L

    2010-03-29

    An analytical theory of extraordinary optical transmission (EOT) through realistic metallic screens perforated by a periodic array of subwavelength holes is presented. The theory is based on our previous work on EOT through perfect conducting screens and on the surface impedance concept. The proposed theory is valid for the complete frequency range where EOT has been reported, including microwaves and optics. A reasonably good agreement with electromagnetic simulations is shown in all this frequency range. We feel that the proposed theory may help to clarify the physics underlying EOT and serve as a first step to more accurate analysis. PMID:20389673

  2. Dynamic apeerture in damping rings with realistic wigglers

    SciTech Connect

    Cai, Yunhai; /SLAC

    2005-05-04

    The International Linear Collider based on superconducting RF cavities requires the damping rings to have extremely small equilibrium emittance, huge circumference, fast damping time, and large acceptance. To achieve all of these requirements is a very challenging task. In this paper, we will present a systematic approach to designing the damping rings using simple cells and non-interlaced sextupoles. The designs of the damping rings with various circumferences and shapes, including dogbone, are presented. To model realistic wigglers, we have developed a new hybrid symplectic integrator for faster and accurate evaluation of dynamic aperture of the lattices.

  3. Emergent properties from organisms to ecosystems: towards a realistic approach

    PubMed Central

    Ponge, Jean-François

    2005-01-01

    More realistic approaches are needed to understand the complexity of ecological systems. Emergent properties of real systems can be used as a basis for a new, neither reductionist nor holistic, approach. Three systems, termed here BUBBLEs, WAVEs and CRYSTALs, have been identified as exhibiting emergent properties. They are non-hierarchical assemblages of individual components, with amplification and connectedness being two main principles that govern their build-up, maintenance and mutual relationships. Examples from various fields of biological and ecological science are referred to, ranging from individual organisms to landscapes. PMID:16094806

  4. Optical Communications Performance with Realistic Weather and Automated Repeat Query

    NASA Astrophysics Data System (ADS)

    Clare, L.; Miles, G.; Breidenthal, J.

    2016-05-01

    Deep-space optical communications are subject to outages arising from deterministic clear line-of-sight dynamics as well as unpredictable weather effects at the ground station. These effects can be mitigated using buffering and automatic retransmission techniques. We provide an analysis that incorporates a realistic weather model based on a two-state Markov chain. Performance for a hypothetical Mars 2022 optical mission is derived incorporating dynamics over an entire 728-day synodic cycle, during which link passes and link data rate vary. Buffer sizing is addressed and operational implications are identified. Also, buffer occupancy results are extended for deep-space missions spanning a range of link data rates.

  5. Turbulence studies in Tokamak boundary plasmas with realistic divertor geometry

    SciTech Connect

    Xu, X.Q.

    1998-10-14

    Results are presented from the 3D nonlocal electromagnetic turbulence code BOUT [1] and the linearized shooting code BAL[2] to study turbulence in tokamak boundary plasmas and its relationship to the L-H transition, in a realistic divertor plasma geometry. The key results include: (1) the identification of the dominant, resistive X-point mode in divertor geometry and (2) turbulence suppression in the L-H transition by shear in the ExB drift speed, ion diamagnetism and finite polarization. Based on the simulation results, a parameterization of the transport is given that includes the dependence on the relevant physical parameters.

  6. Using ultrasound to steer ultrasound contrast agents: Implications for targeted drug delivery

    NASA Astrophysics Data System (ADS)

    Clark, Alicia; Aliseda, Alberto

    2013-11-01

    Ultrasound can be used to manipulate ultrasound contrast agents (UCAs), micron-sized bubbles used in ultrasound imaging to increase image contrast. The Bjerknes force, resulting from the lagged response of the microbubbles to the oscillatory ultrasound pressure field, can be utilized to steer the microbubbles to a targeted area in the vasculature, with the microbubbles serving as drug delivery vectors and injectors. The response of microbubbles to ultrasound in a sheared flow has shown a complex coupling of ultrasound-induced volume oscillations with hydrodynamic forces: Saffman lift and the Bjerknes force. In this work, the relative influence of these two forces acting in the across-streamlines direction is determined as a function of the Reynolds and Womersley and the excitation to bubble natural frequency ratio. We use in-vitro experiments to study the behavior of microbubbles in physiologically-realistic pulsatile flows. Quantitative information about microbubble trajectories in physiological conditions is necessary to develop models in order to control ultrasound steering of bubble-based drug delivery vectors in the human vasculature.

  7. A practical approach for intracellular protein delivery

    PubMed Central

    Biri, Stéphanie; Adib, Abdennaji; Erbacher, Patrick

    2007-01-01

    Protein delivery represents a powerful tool for experiments in live cells including studies of protein-protein interactions, protein interference with blocking antibodies, intracellular trafficking and protein or peptide biological functions. Most available reagents dedicated to the protein delivery allow efficient crossing of the plasma membrane. Nevertheless, the major disadvantage for these reagents is a weak release of the delivered protein into the cytoplasm. In this publication we demonstrate efficient protein delivery with a non-peptide based reagent, in human epithelial carcinoma HeLa cells and primary human skin fibroblasts. Using a fluorescent protein in combination with fluorescence microscopy and fluorescence-assisted cell sorting analysis, we show that the delivered protein is indeed released effectively in the cytoplasm, as expected for a dedicated carrier. Furthermore, we present a step-by-step method to optimize conditions for successful intracellular protein delivery. PMID:19002840

  8. Recent advances in ocular drug delivery.

    PubMed

    Achouri, Djamila; Alhanout, Kamel; Piccerelle, Philippe; Andrieu, Véronique

    2013-11-01

    Amongst the various routes of drug delivery, the field of ocular drug delivery is one of the most interesting and challenging endeavors facing the pharmaceutical scientist. Recent research has focused on the characteristic advantages and limitations of the various drug delivery systems, and further research will be required before the ideal system can be developed. Administration of drugs to the ocular region with conventional delivery systems leads to short contact time of the formulations on the epithelium and fast elimination of drugs. This transient residence time involves poor bioavailability of drugs which can be explained by the tear production, non-productive absorption and impermeability of corneal epithelium. Anatomy of the eye is shortly presented and is connected with ophthalmic delivery and bioavailability of drugs. In the present update on ocular dosage forms, chemical delivery systems such as prodrugs, the use of cyclodextrins to increase solubility of various drugs, the concept of penetration enhancers and other ocular drug delivery systems such as polymeric gels, bioadhesive hydrogels, in-situ forming gels with temperature-, pH-, or osmotically induced gelation, combination of polymers and colloidal systems such as liposomes, niosomes, cubosomes, microemulsions, nanoemulsions and nanoparticles are discussed. Novel ophthalmic delivery systems propose the use of many excipients to increase the viscosity or the bioadhesion of the product. New formulations like gels or colloidal systems have been tested with numerous active substances by in vitro and in vivo studies. Sustained drug release and increase in drug bioavailability have been obtained, offering the promise of innovation in drug delivery systems for ocular administration. Combining different properties of pharmaceutical formulations appears to offer a genuine synergy in bioavailability and sustained release. Promising results are obtained with colloidal systems which present very comfortable

  9. Elective Delivery Before 39 Weeks

    MedlinePlus

    ... Delivery, and Postpartum Care Elective Delivery Before 39 Weeks • What is a “medically indicated” delivery? • What is ... the baby grow and develop during the last weeks of pregnancy? • What are the risks for babies ...

  10. LES of combustion dynamics near blowout in a realistic gas-turbine combustor

    NASA Astrophysics Data System (ADS)

    Esclapez, Lucas; Nik, Medhi B.; Ma, Peter C.; O'Brien, Jeff; Carbajal, Serena; Ihme, Matthias

    2015-11-01

    Driven by increasingly stringent emission regulations, modern gas turbines operate at lean conditions to reduce combustion chamber temperature and NOx emissions. However, as the combustor operates closer to the lean blow-out (LBO) limit, flame stabilization mechanisms are weakened, which increases the risk for complete flame blowout. To better understand the LBO-process, large-eddy simulations of the combustion dynamics near blowout are performed in a realistic two-phase flow combustor. An unstructured incompressible Navier-Stokes solver is used in combination with a Lagrangian dispersed phase formulation. Flame dynamics near and at LBO conditions are studied to identify the role of the liquid fuel composition, spray evaporation, and complex flow pattern on the LBO limit.

  11. Modeling and Simulation for Realistic Propagation Environments of Communications Signals at SHF Band

    NASA Technical Reports Server (NTRS)

    Ho, Christian

    2005-01-01

    In this article, most of widely accepted radio wave propagation models that have proven to be accurate in practice as well as numerically efficient at SHF band will be reviewed. Weather and terrain data along the signal's paths can be input in order to more accurately simulate the propagation environments under particular weather and terrain conditions. Radio signal degradation and communications impairment severity will be investigated through the realistic radio propagation channel simulator. Three types of simulation approaches in predicting signal's behaviors are classified as: deterministic, stochastic and attenuation map. The performance of the simulation can be evaluated under operating conditions for the test ranges of interest. Demonstration tests of a real-time propagation channel simulator will show the capabilities and limitations of the simulation tool and underlying models.

  12. Explicit modeling of human-object interactions in realistic videos.

    PubMed

    Prest, Alessandro; Ferrari, Vittorio; Schmid, Cordelia

    2013-04-01

    We introduce an approach for learning human actions as interactions between persons and objects in realistic videos. Previous work typically represents actions with low-level features such as image gradients or optical flow. In contrast, we explicitly localize in space and track over time both the object and the person, and represent an action as the trajectory of the object w.r.t. to the person position. Our approach relies on state-of-the-art techniques for human detection, object detection, and tracking. We show that this results in human and object tracks of sufficient quality to model and localize human-object interactions in realistic videos. Our human-object interaction features capture the relative trajectory of the object w.r.t. the human. Experimental results on the Coffee and Cigarettes dataset, the video dataset of, and the Rochester Daily Activities dataset show that 1) our explicit human-object model is an informative cue for action recognition; 2) it is complementary to traditional low-level descriptors such as 3D--HOG extracted over human tracks. We show that combining our human-object interaction features with 3D-HOG improves compared to their individual performance as well as over the state of the art. PMID:22889819

  13. Generation of anatomically realistic numerical phantoms for optoacoustic breast imaging

    NASA Astrophysics Data System (ADS)

    Lou, Yang; Mitsuhashi, Kenji; Appleton, Catherine M.; Oraevsky, Alexander; Anastasio, Mark A.

    2016-03-01

    Because optoacoustic tomography (OAT) can provide functional information based on hemoglobin contrast, it is a promising imaging modality for breast cancer diagnosis. Developing an effective OAT breast imaging system requires balancing multiple design constraints, which can be expensive and time-consuming. Therefore, computer- simulation studies are often conducted to facilitate this task. However, most existing computer-simulation studies of OAT breast imaging employ simple phantoms such as spheres or cylinders that over-simplify the complex anatomical structures in breasts, thus limiting the value of these studies in guiding real-world system design. In this work, we propose a method to generate realistic numerical breast phantoms for OAT research based on clinical magnetic resonance imaging (MRI) data. The phantoms include a skin layer that defines breast-air boundary, major vessel branches that affect light absorption in the breast, and fatty tissue and fibroglandular tissue whose acoustical heterogeneity perturbs acoustic wave propagation. By assigning realistic optical and acoustic parameters to different tissue types, we establish both optic and acoustic breast phantoms, which will be exported into standard data formats for cross-platform usage.

  14. Realistic simulation of the Space-borne Compton Polarimeter POLAR

    NASA Astrophysics Data System (ADS)

    Xiao, Hualin

    2016-07-01

    POLAR is a compact wide field space-borne detector dedicated for precise measurements of the linear polarization of hard x-rays emitted by transient sources. Its energy range sensitivity is optimized for the detection of the prompt emission of Gamma-ray bursts (GRBs). POLAR is developed by an international collaboration of China, Switzerland and Poland. It is planned to be launched into space in 2016 onboard the Chinese space laboratory TG2. The energy range of POLAR spans between 50 keV and 500 keV. POLAR detects gamma rays with an array of 1600 plastic scintillator bars read out by 25 muti-anode PMTs (MAPMTs). Polarization measurements use Compton scattering process and are based on detection of energy depositions in the scintillator bars. Reconstruction of the polarization degree and polarization angle of GRBs requires comparison of experimental modulation curves with realistic simulations of the full instrument response. In this paper we present a method to model and parameterize the detector response including efficiency of the light collection, contributions from crosstalk and non-uniformity of MAPMTs as well as dependency on low energy detection thresholds and noise from readout electronics. The performance of POLAR for determination of polarization is predicted with such realistic simulations and carefully cross-checked with dedicated laboratory tests.

  15. Radiation-Spray Coupling for Realistic Flow Configurations

    NASA Technical Reports Server (NTRS)

    El-Asrag, Hossam; Iannetti, Anthony C.

    2011-01-01

    Three Large Eddy Simulations (LES) for a lean-direct injection (LDI) combustor are performed and compared. In addition to the cold flow simulation, the effect of radiation coupling with the multi-physics reactive flow is analyzed. The flame let progress variable approach is used as a subgrid combustion model combined with a stochastic subgrid model for spray atomization and an optically thin radiation model. For accurate chemistry modeling, a detailed Jet-A surrogate mechanism is utilized. To achieve realistic inflow, a simple recycling technique is performed at the inflow section upstream of the swirler. Good comparison is shown with the experimental data mean and root mean square profiles. The effect of combustion is found to change the shape and size of the central recirculation zone. Radiation is found to change the spray dynamics and atomization by changing the heat release distribution and the local temperature values impacting the evaporation process. The simulation with radiation modeling shows wider range of droplet size distribution by altering the evaporation rate. The current study proves the importance of radiation modeling for accurate prediction in realistic spray combustion configurations, even for low pressure systems.

  16. Simulation of Combustion Systems with Realistic g-Jitter

    NASA Technical Reports Server (NTRS)

    Mell, William E.; McGrattan, Kevin B.; Baum, Howard R.

    1999-01-01

    A number of facilities are available for microgravity combustion experiments: aircraft, drop tower, sounding rocket, space shuttle and, in the future, the international space station (ISS). Acceleration disturbances or g-jitter about the background level of reduced gravity exist in all the microgravity facilities. While g-jitter is routinely measured, a quantitative comparison of the quality of g-jitter among the different microgravity facilities has not been compiled. Low frequency g-jitter (< 1 Hz) has been repeatedly observed to disturb a number of combustion systems. Guidelines regarding tolerable levels of acceleration disturbances for a given combustion system have been developed for use in the design of ISS experiments. The validity of these guidelines, however, remains unknown. In this project, recently funded by NASA, a transient, fully three-dimensional simulation code will be developed to simulate the effects of realistic g-jitter on a number of combustion systems. Acceleration disturbances of realistic orientation, magnitude and time dependence will be included in the simulation. Since this is a newly funded project with code development just under-way no simulation results will be presented. Instead, first a short review of the relevant background concerning g-jitter will be given followed by a section on the proposed technical approach.

  17. Ultra-realistic 3-D imaging based on colour holography

    NASA Astrophysics Data System (ADS)

    Bjelkhagen, H. I.

    2013-02-01

    A review of recent progress in colour holography is provided with new applications. Colour holography recording techniques in silver-halide emulsions are discussed. Both analogue, mainly Denisyuk colour holograms, and digitally-printed colour holograms are described and their recent improvements. An alternative to silver-halide materials are the panchromatic photopolymer materials such as the DuPont and Bayer photopolymers which are covered. The light sources used to illuminate the recorded holograms are very important to obtain ultra-realistic 3-D images. In particular the new light sources based on RGB LEDs are described. They show improved image quality over today's commonly used halogen lights. Recent work in colour holography by holographers and companies in different countries around the world are included. To record and display ultra-realistic 3-D images with perfect colour rendering are highly dependent on the correct recording technique using the optimal recording laser wavelengths, the availability of improved panchromatic recording materials and combined with new display light sources.

  18. CHARMM-GUI Membrane Builder toward realistic biological membrane simulations.

    PubMed

    Wu, Emilia L; Cheng, Xi; Jo, Sunhwan; Rui, Huan; Song, Kevin C; Dávila-Contreras, Eder M; Qi, Yifei; Lee, Jumin; Monje-Galvan, Viviana; Venable, Richard M; Klauda, Jeffery B; Im, Wonpil

    2014-10-15

    CHARMM-GUI Membrane Builder, http://www.charmm-gui.org/input/membrane, is a web-based user interface designed to interactively build all-atom protein/membrane or membrane-only systems for molecular dynamics simulations through an automated optimized process. In this work, we describe the new features and major improvements in Membrane Builder that allow users to robustly build realistic biological membrane systems, including (1) addition of new lipid types, such as phosphoinositides, cardiolipin (CL), sphingolipids, bacterial lipids, and ergosterol, yielding more than 180 lipid types, (2) enhanced building procedure for lipid packing around protein, (3) reliable algorithm to detect lipid tail penetration to ring structures and protein surface, (4) distance-based algorithm for faster initial ion displacement, (5) CHARMM inputs for P21 image transformation, and (6) NAMD equilibration and production inputs. The robustness of these new features is illustrated by building and simulating a membrane model of the polar and septal regions of E. coli membrane, which contains five lipid types: CL lipids with two types of acyl chains and phosphatidylethanolamine lipids with three types of acyl chains. It is our hope that CHARMM-GUI Membrane Builder becomes a useful tool for simulation studies to better understand the structure and dynamics of proteins and lipids in realistic biological membrane environments. PMID:25130509

  19. Electron percolation in realistic models of carbon nanotube networks

    NASA Astrophysics Data System (ADS)

    Simoneau, Louis-Philippe; Villeneuve, Jérémie; Rochefort, Alain

    2015-09-01

    The influence of penetrable and curved carbon nanotubes (CNT) on the charge percolation in three-dimensional disordered CNT networks have been studied with Monte-Carlo simulations. By considering carbon nanotubes as solid objects but where the overlap between their electron cloud can be controlled, we observed that the structural characteristics of networks containing lower aspect ratio CNT are highly sensitive to the degree of penetration between crossed nanotubes. Following our efficient strategy to displace CNT to different positions to create more realistic statistical models, we conclude that the connectivity between objects increases with the hard-core/soft-shell radii ratio. In contrast, the presence of curved CNT in the random networks leads to an increasing percolation threshold and to a decreasing electrical conductivity at saturation. The waviness of CNT decreases the effective distance between the nanotube extremities, hence reducing their connectivity and degrading their electrical properties. We present the results of our simulation in terms of thickness of the CNT network from which simple structural parameters such as the volume fraction or the carbon nanotube density can be accurately evaluated with our more realistic models.

  20. Simulating realistic predator signatures in quantitative fatty acid signature analysis

    USGS Publications Warehouse

    Bromaghin, Jeffrey F.

    2015-01-01

    Diet estimation is an important field within quantitative ecology, providing critical insights into many aspects of ecology and community dynamics. Quantitative fatty acid signature analysis (QFASA) is a prominent method of diet estimation, particularly for marine mammal and bird species. Investigators using QFASA commonly use computer simulation to evaluate statistical characteristics of diet estimators for the populations they study. Similar computer simulations have been used to explore and compare the performance of different variations of the original QFASA diet estimator. In both cases, computer simulations involve bootstrap sampling prey signature data to construct pseudo-predator signatures with known properties. However, bootstrap sample sizes have been selected arbitrarily and pseudo-predator signatures therefore may not have realistic properties. I develop an algorithm to objectively establish bootstrap sample sizes that generates pseudo-predator signatures with realistic properties, thereby enhancing the utility of computer simulation for assessing QFASA estimator performance. The algorithm also appears to be computationally efficient, resulting in bootstrap sample sizes that are smaller than those commonly used. I illustrate the algorithm with an example using data from Chukchi Sea polar bears (Ursus maritimus) and their marine mammal prey. The concepts underlying the approach may have value in other areas of quantitative ecology in which bootstrap samples are post-processed prior to their use.

  1. Electron percolation in realistic models of carbon nanotube networks

    SciTech Connect

    Simoneau, Louis-Philippe Villeneuve, Jérémie Rochefort, Alain

    2015-09-28

    The influence of penetrable and curved carbon nanotubes (CNT) on the charge percolation in three-dimensional disordered CNT networks have been studied with Monte-Carlo simulations. By considering carbon nanotubes as solid objects but where the overlap between their electron cloud can be controlled, we observed that the structural characteristics of networks containing lower aspect ratio CNT are highly sensitive to the degree of penetration between crossed nanotubes. Following our efficient strategy to displace CNT to different positions to create more realistic statistical models, we conclude that the connectivity between objects increases with the hard-core/soft-shell radii ratio. In contrast, the presence of curved CNT in the random networks leads to an increasing percolation threshold and to a decreasing electrical conductivity at saturation. The waviness of CNT decreases the effective distance between the nanotube extremities, hence reducing their connectivity and degrading their electrical properties. We present the results of our simulation in terms of thickness of the CNT network from which simple structural parameters such as the volume fraction or the carbon nanotube density can be accurately evaluated with our more realistic models.

  2. Radiation Dose Estimation Using Realistic Postures with PIMAL

    SciTech Connect

    Akkurt, Hatice; Wiarda, Dorothea; Eckerman, Keith F

    2010-12-01

    For correct radiation dose assessment, it is important to take the posture into account. A computational phantom with moving arms and legs was previously developed to address this need. Further, an accompanying graphical user interface (GUI), called PIMAL, was developed to enable dose estimation using realistic postures in a user-friendly manner such that the analyst's time could be substantially reduced. The importance of the posture for correct dose estimation has been demonstrated with a few case studies in earlier analyses. The previous version of PIMAL was somewhat limited in its features (i.e., it contained only a hermaphrodite phantom model and allowed only isotropic source definition). Currently GUI is being further enhanced by incorporating additional phantom models, improving the features, and increasing the user friendliness in general. This paper describes recent updates to the PIMAL software. In this summary recent updates to the PIMAL software, which aims to perform radiation transport simulations for phantom models in realistic postures in a user-friendly manner, are described. In future work additional phantom models, including hybrid phantom models, will be incorporated. In addition to further enhancements, a library of input files for the case studies that have been analyzed to date will be included in the PIMAL.

  3. Functional consequences of realistic biodiversity changes in a marine ecosystem

    PubMed Central

    Bracken, Matthew E. S.; Friberg, Sara E.; Gonzalez-Dorantes, Cirse A.; Williams, Susan L.

    2008-01-01

    Declines in biodiversity have prompted concern over the consequences of species loss for the goods and services provided by natural ecosystems. However, relatively few studies have evaluated the functional consequences of realistic, nonrandom changes in biodiversity. Instead, most designs have used randomly selected assemblages from a local species pool to construct diversity gradients. It is therefore difficult, based on current evidence, to predict the functional consequences of realistic declines in biodiversity. In this study, we used tide pool microcosms to demonstrate that the effects of real-world changes in biodiversity may be very different from those of random diversity changes. Specifically, we measured the relationship between the diversity of a seaweed assemblage and its ability to use nitrogen, a key limiting nutrient in nearshore marine systems. We quantified nitrogen uptake using both experimental and model seaweed assemblages and found that natural increases in diversity resulted in enhanced rates of nitrogen use, whereas random diversity changes had no effect on nitrogen uptake. Our results suggest that understanding the real-world consequences of declining biodiversity will require addressing changes in species performance along natural diversity gradients and understanding the relationships between species' susceptibility to loss and their contributions to ecosystem functioning. PMID:18195375

  4. Simulation of Combustion Systems with Realistic g-jitter

    NASA Technical Reports Server (NTRS)

    Mell, William E.; McGrattan, Kevin B.; Baum, Howard R.

    2003-01-01

    In this project a transient, fully three-dimensional computer simulation code was developed to simulate the effects of realistic g-jitter on a number of combustion systems. The simulation code is capable of simulating flame spread on a solid and nonpremixed or premixed gaseous combustion in nonturbulent flow with simple combustion models. Simple combustion models were used to preserve computational efficiency since this is meant to be an engineering code. Also, the use of sophisticated turbulence models was not pursued (a simple Smagorinsky type model can be implemented if deemed appropriate) because if flow velocities are large enough for turbulence to develop in a reduced gravity combustion scenario it is unlikely that g-jitter disturbances (in NASA's reduced gravity facilities) will play an important role in the flame dynamics. Acceleration disturbances of realistic orientation, magnitude, and time dependence can be easily included in the simulation. The simulation algorithm was based on techniques used in an existing large eddy simulation code which has successfully simulated fire dynamics in complex domains. A series of simulations with measured and predicted acceleration disturbances on the International Space Station (ISS) are presented. The results of this series of simulations suggested a passive isolation system and appropriate scheduling of crew activity would provide a sufficiently "quiet" acceleration environment for spherical diffusion flames.

  5. Towards Modeling Realistic Mobility for Performance Evaluations in MANET

    NASA Astrophysics Data System (ADS)

    Aravind, Alex; Tahir, Hassan

    Simulation modeling plays crucial role in conducting research on complex dynamic systems like mobile ad hoc networks and often the only way. Simulation has been successfully applied in MANET for more than two decades. In several recent studies, it is observed that the credibility of the simulation results in the field has decreased while the use of simulation has steadily increased. Part of this credibility crisis has been attributed to the simulation of mobility of the nodes in the system. Mobility has such a fundamental influence on the behavior and performance of mobile ad hoc networks. Accurate modeling and knowledge of mobility of the nodes in the system is not only helpful but also essential for the understanding and interpretation of the performance of the system under study. Several ideas, mostly in isolation, have been proposed in the literature to infuse realism in the mobility of nodes. In this paper, we attempt a holistic analysis of creating realistic mobility models and then demonstrate creation and analysis of realistic mobility models using a software tool we have developed. Using our software tool, desired mobility of the nodes in the system can be specified, generated, analyzed, and then the trace can be exported to be used in the performance studies of proposed algorithms or systems.

  6. Mucoadhesive vaginal drug delivery systems.

    PubMed

    Acartürk, Füsun

    2009-11-01

    Vaginal delivery is an important route of drug administration for both local and systemic diseases. The vaginal route has some advantages due to its large surface area, rich blood supply, avoidance of the first-pass effect, relatively high permeability to many drugs and self-insertion. The traditional commercial preparations, such as creams, foams, gels, irrigations and tablets, are known to reside in the vaginal cavity for a relatively short period of time owing to the self-cleaning action of the vaginal tract, and often require multiple daily doses to ensure the desired therapeutic effect. The vaginal route appears to be highly appropriate for bioadhesive drug delivery systems in order to retain drugs for treating largely local conditions, or for use in contraception. In particular, protection against sexually-transmitted diseases is critical. To prolong the residence time in the vaginal cavity, bioadhesive therapeutic systems have been developed in the form of semi-solid and solid dosage forms. The most commonly used mucoadhesive polymers that are capable of forming hydrogels are synthetic polyacrylates, polycarbophil, chitosan, cellulose derivatives (hydroxyethycellulose, hydroxy-propylcellulose and hydroxypropylmethylcellulose), hyaluronic acid derivatives, pectin, tragacanth, carrageenan and sodium alginate. The present article is a comprehensive review of the patents related to mucoadhesive vaginal drug delivery systems. PMID:19925443

  7. Project Delivery Methods.

    ERIC Educational Resources Information Center

    Dolan, Thomas G.

    2003-01-01

    Describes project delivery methods that are replacing the traditional Design/Bid/Build linear approach to the management, design, and construction of new facilities. These variations can enhance construction management and teamwork. (SLD)

  8. Delivery by Cesarean Section

    MedlinePlus

    ... Español Text Size Email Print Share Delivery by Cesarean Section Page Content Article Body More than one mother in three gives birth by Cesarean section in the United States (it is also called ...

  9. Assisted Vaginal Delivery

    MedlinePlus

    ... having a repeat assisted vaginal delivery in a future pregnancy? If you have had one assisted vaginal ... a vacuum device. Vacuum Device: A metal or plastic cup that is applied to the fetus’ head ...

  10. Realistic texture extraction for 3D face models robust to self-occlusion

    NASA Astrophysics Data System (ADS)

    Qu, Chengchao; Monari, Eduardo; Schuchert, Tobias; Beyerer, Jürgen

    2015-02-01

    In the context of face modeling, probably the most well-known approach to represent 3D faces is the 3D Morphable Model (3DMM). When 3DMM is fitted to a 2D image, the shape as well as the texture and illumination parameters are simultaneously estimated. However, if real facial texture is needed, texture extraction from the 2D image is necessary. This paper addresses the possible problems in texture extraction of a single image caused by self-occlusion. Unlike common approaches that leverage the symmetric property of the face by mirroring the visible facial part, which is sensitive to inhomogeneous illumination, this work first generates a virtual texture map for the skin area iteratively by averaging the color of neighbored vertices. Although this step creates unrealistic, overly smoothed texture, illumination stays constant between the real and virtual texture. In the second pass, the mirrored texture is gradually blended with the real or generated texture according to the visibility. This scheme ensures a gentle handling of illumination and yet yields realistic texture. Because the blending area only relates to non-informative area, main facial features still have unique appearance in different face halves. Evaluation results reveal realistic rendering in novel poses robust to challenging illumination conditions and small registration errors.

  11. Spontaneous emission in the presence of a realistically sized cylindrical waveguide

    NASA Astrophysics Data System (ADS)

    Dung, Ho Trung

    2016-02-01

    Various quantities characterizing the spontaneous emission process of a dipole emitter including the emission rate and the emission pattern can be expressed in terms of the Green tensor of the surrounding environment. By expanding the Green tensor around some analytically known background one as a Born series, and truncating it under appropriate conditions, complicated boundaries can be tackled with ease. However, when the emitter is embedded in the medium, even the calculation of the first-order term in the Born series is problematic because of the presence of a singularity. We show how to eliminate this singularity for a medium of arbitrary size and shape by expanding around the bulk medium rather than vacuum. In the highly symmetric configuration of an emitter located on the axis of a realistically sized cylinder, it is shown that the singularity can be removed by changing the integral variables and then the order of integration. Using both methods, we investigate the spontaneous emission rate of an initially excited two-level dipole emitter, embedded in a realistically sized cylinder, which can be a common optical fiber in the long-length limit and a disk in the short-length limit. The spatial distribution of the emitted light is calculated using the Born-expansion approach, and local-field corrections to the spontaneous emission rate are briefly discussed.

  12. A computational analysis of sonic booms penetrating a realistic ocean surface.

    PubMed

    Rochat, J L; Sparrow, V W

    2001-03-01

    The last decade has seen a revival of sonic boom research, a direct result of the projected market for a new breed of supersonic passenger aircraft, its design, and its operation. One area of the research involves sonic boom penetration into the ocean, one concern being the possible disturbance of marine mammals from the noise generated by proposed high-speed civil transport (HSCT) flyovers. Although theory is available to predict underwater sound levels due to a sonic boom hitting a homogeneous ocean with a flat surface, theory for a realistic ocean, one with a wavy surface and bubbles near the surface, is missing and will be presented in this paper. First, reviews are given of a computational method to calculate the underwater pressure field and the effects of a simple wavy ocean surface on the impinging sonic boom. Second, effects are described for the implementation of three additional conditions: a sonic boom/ocean "wavelength" comparison, complex ocean surfaces, and bubbles near the ocean surface. Overall, results from the model suggest that the realistic ocean features affect the penetrating proposed HSCT sonic booms by modifying the underwater sound-pressure levels only about 1 decibel or less. PMID:11303944

  13. Computational Aerodynamic Analysis of a Micro-CT Based Bio-Realistic Fruit Fly Wing

    PubMed Central

    Brandt, Joshua; Doig, Graham; Tsafnat, Naomi

    2015-01-01

    The aerodynamic features of a bio-realistic 3D fruit fly wing in steady state (snapshot) flight conditions were analyzed numerically. The wing geometry was created from high resolution micro-computed tomography (micro-CT) of the fruit fly Drosophila virilis. Computational fluid dynamics (CFD) analyses of the wing were conducted at ultra-low Reynolds numbers ranging from 71 to 200, and at angles of attack ranging from -10° to +30°. It was found that in the 3D bio-realistc model, the corrugations of the wing created localized circulation regions in the flow field, most notably at higher angles of attack near the wing tip. Analyses of a simplified flat wing geometry showed higher lift to drag performance values for any given angle of attack at these Reynolds numbers, though very similar performance is noted at -10°. Results have indicated that the simplified flat wing can successfully be used to approximate high-level properties such as aerodynamic coefficients and overall performance trends as well as large flow-field structures. However, local pressure peaks and near-wing flow features induced by the corrugations are unable to be replicated by the simple wing. We therefore recommend that accurate 3D bio-realistic geometries be used when modelling insect wings where such information is useful. PMID:25954946

  14. Ultrasound-mediated gastrointestinal drug delivery

    PubMed Central

    Schoellhammer, Carl M.; Schroeder, Avi; Maa, Ruby; Lauwers, Gregory Yves; Swiston, Albert; Zervas, Michael; Barman, Ross; DiCiccio, Angela M.; Brugge, William R.; Anderson, Daniel G.; Blankschtein, Daniel; Langer, Robert; Traverso, Giovanni

    2016-01-01

    There is a significant clinical need for rapid and efficient delivery of drugs directly to the site of diseased tissues for the treatment of gastrointestinal (GI) pathologies, in particular, Crohn’s and ulcerative colitis. However, complex therapeutic molecules cannot easily be delivered through the GI tract because of physiologic and structural barriers. We report the use of ultrasound as a modality for enhanced drug delivery to the GI tract, with an emphasis on rectal delivery. Ultrasound increased the absorption of model therapeutics inulin, hydrocortisone, and mesalamine two- to tenfold in ex vivo tissue, depending on location in the GI tract. In pigs, ultrasound induced transient cavitation with negligible heating, leading to an order of magnitude enhancement in the delivery of mesalamine, as well as successful systemic delivery of a macromolecule, insulin, with the expected hypoglycemic response. In a rodent model of chemically induced acute colitis, the addition of ultrasound to a daily mesalamine enema (compared to enema alone) resulted in superior clinical and histological scores of disease activity. In both animal models, ultrasound treatment was well tolerated and resulted in minimal tissue disruption, and in mice, there was no significant effect on histology, fecal score, or tissue inflammatory cytokine levels. The use of ultrasound to enhance GI drug delivery is safe in animals and could augment the efficacy of GI therapies and broaden the scope of agents that could be delivered locally and systemically through the GI tract for chronic conditions such as inflammatory bowel disease. PMID:26491078

  15. Nanotransporters for drug delivery.

    PubMed

    Lühmann, Tessa; Meinel, Lorenz

    2016-06-01

    Soluble nanotransporters for drugs can be profiled for targeted delivery particularly to maximize the efficacy of highly potent drugs while minimizing off target effects. This article outlines on the use of biological carrier molecules with a focus on albumin, various drug linkers for site specific release of the drug payload from the nanotransporter and strategies to combine these in various ways to meet different drug delivery demands particularly the optimization of the payload per nanotransporter. PMID:26773302

  16. [Transdermal Delivery of NSAIDs].

    PubMed

    Nakajima, Takehisa; Makino, Kimiko

    2015-11-01

    Skin has been studied as administration site of drug for its systemic effects, since systemic therapeutic agents can be delivered for long time with a controlled ratio, escaping from the first pass effect by liver by the transdermal delivery, which can decrease the dosage form. The low permeability of drug molecules through stratum corneum has been the limiting factor for developing transdermal delivery system of therapeutic agents. To enhance the permeability of drug molecules, many studies have been reported. PMID:26689064

  17. Mode engineering for realistic quantum-enhanced interferometry

    NASA Astrophysics Data System (ADS)

    Jachura, Michał; Chrapkiewicz, Radosław; Demkowicz-Dobrzański, Rafał; Wasilewski, Wojciech; Banaszek, Konrad

    2016-04-01

    Quantum metrology overcomes standard precision limits by exploiting collective quantum superpositions of physical systems used for sensing, with the prominent example of non-classical multiphoton states improving interferometric techniques. Practical quantum-enhanced interferometry is, however, vulnerable to imperfections such as partial distinguishability of interfering photons. Here we introduce a method where appropriate design of the modal structure of input photons can alleviate deleterious effects caused by another, experimentally inaccessible degree of freedom. This result is accompanied by a laboratory demonstration that a suitable choice of spatial modes combined with position-resolved coincidence detection restores entanglement-enhanced precision in the full operating range of a realistic two-photon Mach-Zehnder interferometer, specifically around a point which otherwise does not even attain the shot-noise limit due to the presence of residual distinguishing information in the spectral degree of freedom. Our method highlights the potential of engineering multimode physical systems in metrologic applications.

  18. Ring Current Modeling in a Realistic Magnetic Field Configuration

    NASA Technical Reports Server (NTRS)

    Fok, M.-C.; Moore, T. E.

    1997-01-01

    A 3-dimensional kinetic model has been developed to study the dynamics of the storm time ring current in a dipole magnetic field. In this paper, the ring current model is extended to include a realistic, time-varying magnetic field model. The magnetic field is expressed as the cross product of the gradients of two Euler potentials and the bounce-averaged particle drifts are calculated in the Euler potential coordinates. A dipolarization event is modeled by collapsing a tail-like magnetosphere to a dipole-like configuration. Our model is able to simulate the sudden enhancements in the ring current ion fluxes and the corresponding ionospheric precipitation during the substorm expansion.

  19. Mode engineering for realistic quantum-enhanced interferometry

    PubMed Central

    Jachura, Michał; Chrapkiewicz, Radosław; Demkowicz-Dobrzański, Rafał; Wasilewski, Wojciech; Banaszek, Konrad

    2016-01-01

    Quantum metrology overcomes standard precision limits by exploiting collective quantum superpositions of physical systems used for sensing, with the prominent example of non-classical multiphoton states improving interferometric techniques. Practical quantum-enhanced interferometry is, however, vulnerable to imperfections such as partial distinguishability of interfering photons. Here we introduce a method where appropriate design of the modal structure of input photons can alleviate deleterious effects caused by another, experimentally inaccessible degree of freedom. This result is accompanied by a laboratory demonstration that a suitable choice of spatial modes combined with position-resolved coincidence detection restores entanglement-enhanced precision in the full operating range of a realistic two-photon Mach–Zehnder interferometer, specifically around a point which otherwise does not even attain the shot-noise limit due to the presence of residual distinguishing information in the spectral degree of freedom. Our method highlights the potential of engineering multimode physical systems in metrologic applications. PMID:27125782

  20. Unsteady velocity measurements in a realistic intracranial aneurysm model

    NASA Astrophysics Data System (ADS)

    Ugron, Ádám; Farinas, Marie-Isabelle; Kiss, László; Paál, György

    2012-01-01

    The initiation, growth and rupture of intracranial aneurysms are intensively studied by computational fluid dynamics. To gain confidence in the results of numerical simulations, validation of the results is necessary. To this end the unsteady flow was measured in a silicone phantom of a realistic intracranial aneurysm. A flow circuit was built with a novel unsteady flow rate generating method, used to model the idealised shape of the heartbeat. This allowed the measurement of the complex three-dimensional velocity distribution by means of laser-optical methods such as laser doppler anemometry (LDA) and particle image velocimetry (PIV). The PIV measurements, available with high temporal and spatial distribution, were found to have good agreement with the control LDA measurements. Furthermore, excellent agreement was found with the numerical results.

  1. Realistic facial animation generation based on facial expression mapping

    NASA Astrophysics Data System (ADS)

    Yu, Hui; Garrod, Oliver; Jack, Rachael; Schyns, Philippe

    2014-01-01

    Facial expressions reflect internal emotional states of a character or in response to social communications. Though much effort has been taken to generate realistic facial expressions, it still remains a challenging topic due to human being's sensitivity to subtle facial movements. In this paper, we present a method for facial animation generation, which reflects true facial muscle movements with high fidelity. An intermediate model space is introduced to transfer captured static AU peak frames based on FACS to the conformed target face. And then dynamic parameters derived using a psychophysics method is integrated to generate facial animation, which is assumed to represent natural correlation of multiple AUs. Finally, the animation sequence in the intermediate model space is mapped to the target face to produce final animation.

  2. Ultra-realistic imaging and OptoClones

    NASA Astrophysics Data System (ADS)

    Bjelkhagen, Hans I.; Lembessis, Alkiviadis; Sarakinos, Andreas

    2016-03-01

    Recent improvements in solid state CW lasers, recording materials and light sources (such as LED lights) for displaying color holograms are described. Full-color analogue holograms can now be created with substantially better image characteristics than previously possible. To record ultra-realistic images depends on selecting the optimal recording laser wavelengths and employing ultra-fine-grain, silver-halide materials. The image quality is improved by using LED display light with improved spatial coherence. Recording museum artifacts using mobile holographic equipment is described. The most recent recorded such holograms (referred to as OptoClones™) are the Fabergé Eggs at the Fabergé Museum in St. Petersburg, Russia.

  3. [Long-term realistically life-threatening disease].

    PubMed

    Berent, Jarosław; Jurczyk, Agnieszka P; Markuszewski, Leszek; Szram, Stefan

    2004-01-01

    In this paper the authors discuss a legal code description of a wrongly included (as a result of a legislative error) "long-term really life-threatening disease" (dlugotrwala choroba realnie zagrazajaca zyciu) in the Criminal Code. This category of disease impossible to apply in practice since its terms "long-term" and "realistically life-threatening" are mutually exclusive--is nonetheless applicable to crimes committed from Sept. 1, 1998 to Dec. 8, 2003. In effect this causes a change in the qualification of certain acts in Art. 156 of the Criminal Code, to include those in Art. 157, Paragraph 1, and in some cases, even extending to acts named in Art. 157, Paragraph 2 of the Criminal Code. PMID:15782782

  4. Ab initio H2O in realistic hydrophilic confinement.

    PubMed

    Allolio, Christoph; Klameth, Felix; Vogel, Michael; Sebastiani, Daniel

    2014-12-15

    A protocol for the ab initio construction of a realistic cylindrical pore in amorphous silica, serving as a geometric nanoscale confinement for liquids and solutions, is presented. Upon filling the pore with liquid water at different densities, the structure and dynamics of the liquid inside the confinement can be characterized. At high density, the pore introduces long-range oscillations into the water density profile, which makes the water structure unlike that of the bulk across the entire pore. The tetrahedral structure of water is also affected up to the second solvation shell of the pore wall. Furthermore, the effects of the confinement on hydrogen bonding and diffusion, resulting in a weakening and distortion of the water structure at the pore walls and a slowdown in diffusion, are characterized. PMID:25208765

  5. Realistic irrigation visualization in a surgical wound debridement simulator.

    PubMed

    Shen, Yuzhong; Seevinck, Jennifer; Baydogan, Emre

    2006-01-01

    Wound debridement refers to the removal of necrotic, devitalized, or contaminated tissue and/or foreign material to promote wound healing. Surgical debridement uses sharp instruments to cut dead tissue from a wound and it is the quickest and most efficient method of debridement. A wound debridement simulator can ensure that a medical trainee is competent prior to performing a procedure on a genuine patient. Irrigation is performed at different stages of debridement in order to remove debris and reduce the bacteria count through rinsing the wound. This paper presents a novel approach for realistic irrigation visualization based on texture representations of debris. This approach applies image processing techniques to a series of images, which model the cleanliness of the wound. The active texture is generated and updated dynamically based on the irrigation state, location, and range. Presented results demonstrate that texture mapping and image processing techniques can provide effective and efficient solutions for irrigation visualization in the wound debridement simulator. PMID:16404110

  6. Design for and efficient dynamic climate model with realistic geography

    NASA Technical Reports Server (NTRS)

    Suarez, M. J.; Abeles, J.

    1984-01-01

    The long term climate sensitivity which include realistic atmospheric dynamics are severely restricted by the expense of integrating atmospheric general circulation models are discussed. Taking as an example models used at GSFC for this dynamic model is an alternative which is of much lower horizontal or vertical resolution. The model of Heid and Suarez uses only two levels in the vertical and, although it has conventional grid resolution in the meridional direction, horizontal resolution is reduced by keeping only a few degrees of freedom in the zonal wavenumber spectrum. Without zonally asymmetric forcing this model simulates a day in roughly 1/2 second on a CRAY. The model under discussion is a fully finite differenced, zonally asymmetric version of the Heid-Suarez model. It is anticipated that speeds can be obtained a few seconds a day roughly 50 times faster than moderate resolution, multilayer GCM's.

  7. The Free Will Theorem and Limits on Realistic Theories

    NASA Astrophysics Data System (ADS)

    Godfrey, Christopher

    2010-03-01

    The rGRWf model (Tumulka 2006) is a proposed solution of the measurement problem of quantum mechanics involving a stochastic nonlinear wave equation embedded in a relativistic framework. Its primary feature is a mechanism that suppresses superpositions of macroscopically different states for macroscopic systems. However, the Free Will Theorem (FWT) proposed by Conway and Kochen (Conway and Kochen 2007, 2009) purports to prove that no theory that is both non-deterministic and relativistic can reproduce all possible measurement results on a system of two entangled spin-one particles. Here we examine both the rGRWf model and the FWT. It is demonstrated that underlying assumptions in the postulates of the FWT rule out certain classes of realistic physical theories. These underlying assumptions and the characteristics of physical theories permitted by the FWT axioms are discussed.

  8. Mode engineering for realistic quantum-enhanced interferometry.

    PubMed

    Jachura, Michał; Chrapkiewicz, Radosław; Demkowicz-Dobrzański, Rafał; Wasilewski, Wojciech; Banaszek, Konrad

    2016-01-01

    Quantum metrology overcomes standard precision limits by exploiting collective quantum superpositions of physical systems used for sensing, with the prominent example of non-classical multiphoton states improving interferometric techniques. Practical quantum-enhanced interferometry is, however, vulnerable to imperfections such as partial distinguishability of interfering photons. Here we introduce a method where appropriate design of the modal structure of input photons can alleviate deleterious effects caused by another, experimentally inaccessible degree of freedom. This result is accompanied by a laboratory demonstration that a suitable choice of spatial modes combined with position-resolved coincidence detection restores entanglement-enhanced precision in the full operating range of a realistic two-photon Mach-Zehnder interferometer, specifically around a point which otherwise does not even attain the shot-noise limit due to the presence of residual distinguishing information in the spectral degree of freedom. Our method highlights the potential of engineering multimode physical systems in metrologic applications. PMID:27125782

  9. Atomistic Simulation of Polymer Crystallization at Realistic Length Scales

    SciTech Connect

    Gee, R H; Fried, L E

    2005-01-28

    Understanding the dynamics of polymer crystallization during the induction period prior to crystal growth is a key goal in polymer physics. Here we present the first study of primary crystallization of polymer melts via molecular dynamics simulations at physically realistic (about 46 nm) length scales. Our results show that the crystallization mechanism involves a spinodal decomposition microphase separation caused by an increase in the average length of rigid trans segments along the polymer backbone during the induction period. Further, the characteristic length of the growing dense domains during the induction period is longer than predicted by classical nucleation theory. These results indicate a new 'coexistence period' in the crystallization, where nucleation and growth mechanisms coexist with a phase separation mechanism. Our results provide an atomistic verification of the fringed micelle model.

  10. Tool for Generating Realistic Residential Hot Water Event Schedules: Preprint

    SciTech Connect

    Hendron, B.; Burch, J.; Barker, G.

    2010-08-01

    The installed energy savings for advanced residential hot water systems can depend greatly on detailed occupant use patterns. Quantifying these patterns is essential for analyzing measures such as tankless water heaters, solar hot water systems with demand-side heat exchangers, distribution system improvements, and recirculation loops. This paper describes the development of an advanced spreadsheet tool that can generate a series of year-long hot water event schedules consistent with realistic probability distributions of start time, duration and flow rate variability, clustering, fixture assignment, vacation periods, and seasonality. This paper also presents the application of the hot water event schedules in the context of an integral-collector-storage solar water heating system in a moderate climate.

  11. Resolving conflict realistically in today's health care environment.

    PubMed

    Smith, S B; Tutor, R S; Phillips, M L

    2001-11-01

    Conflict is a natural part of human interaction, and when properly addressed, results in improved interpersonal relationships and positive organizational culture. Unchecked conflict may escalate to verbal and physical violence. Conflict that is unresolved creates barriers for people, teams, organizational growth, and productivity, leading to cultural disintegration within the establishment. By relying on interdependence and professional collaboration, all parties involved grow and, in turn, benefit the organization and population served. When used in a constructive manner, conflict resolution can help all parties involved see the whole picture, thus allowing freedom for growth and change. Conflict resolution is accomplished best when emotions are controlled before entering into negotiation. Positive confrontation, problem solving, and negotiation are processes used to realistically resolve conflict. Everyone walks away a winner when conflict is resolved in a positive, professional manner (Stone, 1999). PMID:11725427

  12. Implementation of realistic image rendition algorithm based on DSP

    NASA Astrophysics Data System (ADS)

    Lv, Lily; Gao, Kun; Ni, Guoqiang; Zhou, Liwei; Shao, Xiaoguang

    2010-11-01

    Realistic image rendition is to reproduce the human perception of natural scenes. Retinex is a classical algorithm that simultaneously provides high dynamic range compression contrast and color constancy of an image. In this paper, we discuss a design of a digital signal processor (DSP) implementation of the single scale monochromatic Retinex algorithm. The target processor is Texas Instruments TMS320DM642, a 32-bit fix point DSP which is clocked at 600 MHz. This DSP hardware platform designed is of powerful consumption and video image processing capability. We give an overview of the DSP hardware and software, and discuss some feasible optimizations to achieve a real-time version of the Retinex algorithm. In the end, the performance of the algorithm executing on DSP platform is shown.

  13. Considerations for realistic ECCS evaluation methodology for LWRs

    SciTech Connect

    Rohatgi, U.S.; Saha, P.; Chexal, V.K.

    1985-01-01

    This paper identifies the various phenomena which govern the course of large and small break LOCAs in LWRs, and affect the key parameters such as Peak Clad Temperature (PCT) and timing of the end of blowdown, beginning of reflood, PCT, and complete quench. A review of the best-estimate models and correlations for these phenomena in the current literature has been presented. Finally, a set of models have been recommended which may be incorporated in a present best-estimate code such as TRAC or RELAP5 in order to develop a realistic ECCS evaluation methodology for future LWRs and have also been compared with the requirements of current ECCS evaluation methodology as outlined in Appendix K of 10CFR50. 58 refs.

  14. Climate Sensitivity to Realistic Solar Heating of Snow and Ice

    NASA Astrophysics Data System (ADS)

    Flanner, M.; Zender, C. S.

    2004-12-01

    Snow and ice-covered surfaces are highly reflective and play an integral role in the planetary radiation budget. However, GCMs typically prescribe snow reflection and absorption based on minimal knowledge of snow physical characteristics. We performed climate sensitivity simulations with the NCAR CCSM including a new physically-based multi-layer snow radiative transfer model. The model predicts the effects of vertically resolved heating, absorbing aerosol, and snowpack transparency on snowpack evolution and climate. These processes significantly reduce the model's near-infrared albedo bias over deep snowpacks. While the current CCSM implementation prescribes all solar radiative absorption to occur in the top 2 cm of snow, we estimate that about 65% occurs beneath this level. Accounting for the vertical distribution of snowpack heating and more realistic reflectance significantly alters snowpack depth, surface albedo, and surface air temperature over Northern Hemisphere regions. Implications for the strength of the ice-albedo feedback will be discussed.

  15. Optimal continuous variable quantum teleportation protocol for realistic settings

    NASA Astrophysics Data System (ADS)

    Luiz, F. S.; Rigolin, Gustavo

    2015-03-01

    We show the optimal setup that allows Alice to teleport coherent states | α > to Bob giving the greatest fidelity (efficiency) when one takes into account two realistic assumptions. The first one is the fact that in any actual implementation of the continuous variable teleportation protocol (CVTP) Alice and Bob necessarily share non-maximally entangled states (two-mode finitely squeezed states). The second one assumes that Alice's pool of possible coherent states to be teleported to Bob does not cover the whole complex plane (| α | < ∞). The optimal strategy is achieved by tuning three parameters in the original CVTP, namely, Alice's beam splitter transmittance and Bob's displacements in position and momentum implemented on the teleported state. These slight changes in the protocol are currently easy to be implemented and, as we show, give considerable gain in performance for a variety of possible pool of input states with Alice.

  16. High-definition displays for realistic simulator and trainer systems

    NASA Astrophysics Data System (ADS)

    Daniels, Reginald; Hopper, Darrel G.; Beyer, Steve; Peppler, Philipp W.

    1998-09-01

    Current flight simulators and trainers do not provide acceptable levels of visual display performance (performance that would allow ground based trainers to economically replace aircraft flying training) for many air-to-air and air-to- ground training scenarios. Ground training for pilots could be made significantly more realistic, allowing the ground-based curricula to be enlarged. The enhanced ground based training could then more readily augment actual aircraft flying (training) time. This paper presents the technology need and opportunity to create a new class of immersive simulator- trainer systems having some 210 million pixels characterized especially by a 20-20 visual acuity synthetic vision system having some 150 million pixels. The same new display technology base is needed for planned crew stations for uninhabited combat air vehicles (UCAV), advanced aircraft cockpits and mission crewstations, and for the space plane.

  17. Fighting noise with noise in realistic quantum teleportation

    NASA Astrophysics Data System (ADS)

    Fortes, Raphael; Rigolin, Gustavo

    2015-07-01

    We investigate how the efficiency of the quantum teleportation protocol is affected when the qubits involved in the protocol are subjected to noise or decoherence. We study all types of noise usually encountered in real-world implementations of quantum communication protocols, namely, the bit-flip, phase-flip (phase damping), depolarizing, and amplitude-damping noise. Several realistic scenarios are studied in which a part or all of the qubits employed in the execution of the quantum teleportation protocol are subjected to the same or different types of noise. We find noise scenarios not yet known in which more noise or less entanglement lead to more efficiency. Furthermore, we show that if noise is unavoidable it is better to subject the qubits to different noise channels in order to obtain an increase in the efficiency of the protocol.

  18. Realistic Mobility Modeling for Vehicular Ad Hoc Networks

    NASA Astrophysics Data System (ADS)

    Akay, Hilal; Tugcu, Tuna

    2009-08-01

    Simulations used for evaluating the performance of routing protocols for Vehicular Ad Hoc Networks (VANET) are mostly based on random mobility and fail to consider individual behaviors of the vehicles. Unrealistic assumptions about mobility produce misleading results about the behavior of routing protocols in real deployments. In this paper, a realistic mobility modeling tool, Mobility for Vehicles (MOVE), which considers the basic mobility behaviors of vehicles, is proposed for a more accurate evaluation. The proposed model is tested against the Random Waypoint (RWP) model using AODV and OLSR protocols. The results show that the mobility model significantly affects the number of nodes within the transmission range of a node, the volume of control traffic, and the number of collisions. It is shown that number of intersections, grid size, and node density are important parameters when dealing with VANET performance.

  19. Generating realistic environments for cyber operations development, testing, and training

    NASA Astrophysics Data System (ADS)

    Berk, Vincent H.; Gregorio-de Souza, Ian; Murphy, John P.

    2012-06-01

    Training eective cyber operatives requires realistic network environments that incorporate the structural and social complexities representative of the real world. Network trac generators facilitate repeatable experiments for the development, training and testing of cyber operations. However, current network trac generators, ranging from simple load testers to complex frameworks, fail to capture the realism inherent in actual environments. In order to improve the realism of network trac generated by these systems, it is necessary to quantitatively measure the level of realism in generated trac with respect to the environment being mimicked. We categorize realism measures into statistical, content, and behavioral measurements, and propose various metrics that can be applied at each level to indicate how eectively the generated trac mimics the real world.

  20. Application of the Probabilistic Dynamic Synthesis Method to Realistic Structures

    NASA Technical Reports Server (NTRS)

    Brown, Andrew M.; Ferri, Aldo A.

    1998-01-01

    The Probabilistic Dynamic Synthesis method is a technique for obtaining the statistics of a desired response engineering quantity for a structure with non-deterministic parameters. The method uses measured data from modal testing of the structure as the input random variables, rather than more "primitive" quantities like geometry or material variation. This modal information is much more comprehensive and easily measured than the "primitive" information. The probabilistic analysis is carried out using either response surface reliability methods or Monte Carlo simulation. In previous work, the feasibility of the PDS method applied to a simple seven degree-of-freedom spring-mass system was verified. In this paper, extensive issues involved with applying the method to a realistic three-substructure system are examined, and free and forced response analyses are performed. The results from using the method are promising, especially when the lack of alternatives for obtaining quantitative output for probabilistic structures is considered.

  1. Computed rotational rainbows from realistic potential energy surfaces

    SciTech Connect

    Gianturco, F.A.; Palma, A.

    1985-08-01

    The quantal IOS approximation in here employed to study interference structures in the rotationally inelastic, state-to-state differential cross sections for polar diatomic targets (LiH, FH, and CO) interacting with He atoms. Quite realistic expressions are used to describe the relevant potential energy surfaces (PES) which were taken from previous works that tested them against accurate experimental findings for total and partial differential cross sections. Specific features like short-range anisotropy and well depth, long-range attractive regions and overall range of action for each potential employed are analyzed and discussed in relation to their influence on rotational rainbows appearance and on the possible observation of cross section extrema in rotational energy distributions.

  2. Computer simulations of realistic three-dimensional microstructures

    NASA Astrophysics Data System (ADS)

    Mao, Yuxiong

    A novel and efficient methodology is developed for computer simulations of realistic two-dimensional (2D) and three-dimensional (3D) microstructures. The simulations incorporate realistic 2D and 3D complex morphologies/shapes, spatial patterns, anisotropy, volume fractions, and size distributions of the microstructural features statistically similar to those in the corresponding real microstructures. The methodology permits simulations of sufficiently large 2D as well as 3D microstructural windows that incorporate short-range (on the order of particle/feature size) as well as long-range (hundred times the particle/feature size) microstructural heterogeneities and spatial patterns at high resolution. The utility of the technique has been successfully demonstrated through its application to the 2D microstructures of the constituent particles in wrought Al-alloys, the 3D microstructure of discontinuously reinforced Al-alloy (DRA) composites containing SiC particles that have complex 3D shapes/morphologies and spatial clustering, and 3D microstructure of boron modified Ti-6Al-4V composites containing fine TiB whiskers and coarse primary TiB particles. The simulation parameters are correlated with the materials processing parameters (such as composition, particle size ratio, extrusion ratio, extrusion temperature, etc.), which enables the simulations of rational virtual 3D microstructures for the parametric studies on microstructure-properties relationships. The simulated microstructures have been implemented in the 3D finite-elements (FE)-based framework for simulations of micro-mechanical response and stress-strain curves. Finally, a new unbiased and assumption free dual-scale virtual cycloids probe for estimating surface area of 3D objects constructed by 2D serial section images is also presented.

  3. An anatomically realistic brain phantom for quantification with positron tomography

    SciTech Connect

    Wong, D.F.; Links, J.M.; Molliver, M.E.; Hengst, T.C.; Clifford, C.M.; Buhle, L.; Bryan, M.; Stumpf, M.; Wagner, H.N. Jr.

    1984-01-01

    Phantom studies are useful in assessing and maximizing the accuracy and precision of quantification of absolute activity, assessing errors associated with patient positioning, and dosimetry. Most phantoms are limited by the use of simple shapes, which do not adequately reflect real anatomy. The authors have constructed an anatomically realistic life-size brain phantom for positron tomography studies. The phantom consists of separately fillable R + L caudates, R + L putamens, R + L globus passidus and cerebellum. These structures are contained in proper anatomic orientation within a fillable cerebrum. Solid ventricles are also present. The entire clear vinyl cerebrum is placed in a human skull. The internal brain structures were fabricated from polyester resin, with dimensions, shapes and sizes of the structures obtained from digitized contours of brain slices in the U.C.S.D. computerized brain atlas. The structures were filled with known concentrations of Ga-68 in water and scanned with our NeuroECAT. The phantom was aligned in the scanner for each structure, such that the tomographic slice passed through that structure's center. After calibration of the scanner with a standard phantom for counts/pixel uCi/cc conversion, the measured activity concentrations were compared with the actual concentrations. The ratio of measured to actual activity concentration (''recovery coefficient'') for the caudate was 0.33; for the putamen 0.42. For comparison, the ratio for spheres of diameters 9.5, 16,19 and 25.4 mm was 0.23, 0.54, 0.81, and 0.93. This phantom provides more realistic assessment of performance and allows calculation of correction factors.

  4. Modeling and Analysis of Realistic Fire Scenarios in Spacecraft

    NASA Technical Reports Server (NTRS)

    Brooker, J. E.; Dietrich, D. L.; Gokoglu, S. A.; Urban, D. L.; Ruff, G. A.

    2015-01-01

    An accidental fire inside a spacecraft is an unlikely, but very real emergency situation that can easily have dire consequences. While much has been learned over the past 25+ years of dedicated research on flame behavior in microgravity, a quantitative understanding of the initiation, spread, detection and extinguishment of a realistic fire aboard a spacecraft is lacking. Virtually all combustion experiments in microgravity have been small-scale, by necessity (hardware limitations in ground-based facilities and safety concerns in space-based facilities). Large-scale, realistic fire experiments are unlikely for the foreseeable future (unlike in terrestrial situations). Therefore, NASA will have to rely on scale modeling, extrapolation of small-scale experiments and detailed numerical modeling to provide the data necessary for vehicle and safety system design. This paper presents the results of parallel efforts to better model the initiation, spread, detection and extinguishment of fires aboard spacecraft. The first is a detailed numerical model using the freely available Fire Dynamics Simulator (FDS). FDS is a CFD code that numerically solves a large eddy simulation form of the Navier-Stokes equations. FDS provides a detailed treatment of the smoke and energy transport from a fire. The simulations provide a wealth of information, but are computationally intensive and not suitable for parametric studies where the detailed treatment of the mass and energy transport are unnecessary. The second path extends a model previously documented at ICES meetings that attempted to predict maximum survivable fires aboard space-craft. This one-dimensional model implies the heat and mass transfer as well as toxic species production from a fire. These simplifications result in a code that is faster and more suitable for parametric studies (having already been used to help in the hatch design of the Multi-Purpose Crew Vehicle, MPCV).

  5. Toward the redesign of nutrition delivery.

    PubMed

    Lamppa, John W; Horn, Greg; Edwards, David

    2014-09-28

    In the facilitation of widespread access to low-cost, good tasting food, the global food system has relied on the use of fat, sugar, chemical processing aids and plastics, among other elements potentially detrimental to human health and the environment. This contrasts starkly with the strategies of natural nutrition delivery systems. Rich in vitamins, minerals, and other substances of functional benefit to human health, natural delivery systems, such as fruits and vegetables, retain their physical and chemical stability in a range of conditions over relatively long times through protective skins and shells that can either be eaten or degrade rapidly and fully in nature. Frequently natural foods can be delivered in small (even extremely small) portions, as with berries, insects, plankton and krill, permitting portion control and the rapid and efficient delivery of functional nutrition in inherently mobile circumstances. These and other qualities, which have insured the sustainable and healthy nourishment of animals and humans for at least tens of thousands of years, are often absent from today's man-made food and beverage delivery systems. With growing awareness of the liabilities to maintaining the food system of today, efforts are now underway to redesign nutrition delivery so as to provide the contemporary benefits of global access while retrieving the health and environmental benefits associated with natural delivery systems. We review these here, with special attention to recently commercialized nutritional delivery systems emerging from the drug delivery field aimed at reducing waste in food and beverage (nutritional aerosols) and eliminating waste in food and beverage packaging (edible skins). We briefly discuss the potential ramifications to how we will eat tomorrow. PMID:24878187

  6. Novel ionically crosslinked acrylamide-grafted poly(vinyl alcohol)/sodium alginate/sodium carboxymethyl cellulose pH-sensitive microspheres for delivery of Alzheimer's drug donepezil hydrochloride: Preparation and optimization of release conditions.

    PubMed

    Bulut, Emine; Şanlı, Oya

    2016-01-01

    In this work, the graft copolymer, poly(vinyl alcohol)-grafted polyacrylamide (PVA-g-PAAm), was synthesized and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and elemental analysis. Microspheres of PVA-g-PAAm/sodium alginate (NaAlg)/sodium carboxymethyl cellulose (NaCMC) were prepared by the emulsion-crosslinking method and used for the delivery of an Alzheimer's drug, donepezil hydrochloride (DP). The release of DP increased with the increase in drug/polymer ratio (d/p) and PVA-g-PAAm/NaAlg/NaCMC ratio, while it decreased with the increase in the extent of crosslinking. The optimum DP release was obtained as 92.9% for a PVA-g-PAAm/NaAlg/NaCMC ratio of 1/2/1, d/p ratio of 1/8, and FeCl3 concentration of 7% (w/v). PMID:25301684

  7. Matching and Conditioned Reinforcement Rate

    PubMed Central

    Shahan, Timothy A; Podlesnik, Christopher A; Jimenez-Gomez, Corina

    2006-01-01

    Attempts to examine the effects of variations in relative conditioned reinforcement rate on choice have been confounded by changes in rates of primary reinforcement or changes in the value of the conditioned reinforcer. To avoid these problems, this experiment used concurrent observing responses to examine sensitivity of choice to relative conditioned reinforcement rate. In the absence of observing responses, unsignaled periods of food delivery on a variable-interval 90-s schedule alternated with extinction on a center key (i.e., a mixed schedule was in effect). Two concurrently available observing responses produced 15-s access to a stimulus differentially associated with the schedule of food delivery (S+). The relative rate of S+ deliveries arranged by independent variable-interval schedules for the two observing responses varied across conditions. The relation between the ratio of observing responses and the ratio of S+ deliveries was well described by the generalized matching law, despite the absence of changes in the rate of food delivery. In addition, the value of the S+ deliveries likely remained constant across conditions because the ratio of S+ to mixed schedule food deliveries remained constant. Assuming that S+ deliveries serve as conditioned reinforcers, these findings are consistent with the functional similarity between primary and conditioned reinforcers suggested by general choice theories based on the concatenated matching law (e.g., contextual choice and hyperbolic value-added models). These findings are inconsistent with delay reduction theory, which has no terms for the effects of rate of conditioned reinforcement in the absence of changes in rate of primary reinforcement. PMID:16673824

  8. Tomographic immersed boundary method for permeability prediction of realistic porous media: Simulation and experimental validation

    NASA Astrophysics Data System (ADS)

    Penha, D. J. Lopez; Geurts, B. J.; Nordlund, M.; Kuczaj, A. K.; Zinovik, I.; Winkelmann, C.; Mikhal, J.

    2012-05-01

    In this paper we demonstrate the ability of a volume-penalizing immersed boundary method to predict pore-scale fluid transport in realistic porous media. A numerical experiment is designed that recreates the exact conditions of a real flow experiment through a fibrous porous medium. Under a constant volumetric flow rate air is forced through the porous sample and the pressure drop across its length is accurately measured. The exact pore geometry is obtained using highresolution micro-computed tomography, and the data is, after processing, directly inserted into the flow solver. Simulations are performed on a uniform Cartesian grid, spanning the entire physical domain (i.e., including both fluid and solid regions)— a feature which represents one of the major benefits of volume penalization. We demonstrate that the numerical results agree well with the experiment and that an error of approximately < 10% is attainable on a grid of 512×256×256 cells.

  9. Analysis of unregulated emissions from an off-road diesel engine during realistic work operations

    NASA Astrophysics Data System (ADS)

    Lindgren, Magnus; Arrhenius, Karine; Larsson, Gunnar; Bäfver, Linda; Arvidsson, Hans; Wetterberg, Christian; Hansson, Per-Anders; Rosell, Lars

    2011-09-01

    Emissions from vehicle diesel engines constitute a considerable share of anthropogenic emissions of pollutants, including many non-regulated compounds such as aromatic hydrocarbons and alkenes. One way to reduce these emissions might be to use fuels with low concentrations of aromatic hydrocarbons, such as Fischer-Tropsch (F-T) diesels. Therefore this study compared Swedish Environmental Class 1 diesel (EC1) with the F-T diesel fuel Ecopar™ in terms of emissions under varied conditions (steady state, controlled transients and realistic work operations) in order to identify factors influencing emissions in actual operation. Using F-T diesel reduced emissions of aromatic hydrocarbons, but not alkenes. Emissions were equally dependent on work operation character (load, engine speed, occurrence of transients) for both fuels. There were indications that the emissions originated from unburnt fuel, rather than from combustion products.

  10. Study of airflow during respiratory cycle in semi-realistic model of human tracheobronchial tree

    NASA Astrophysics Data System (ADS)

    Elcner, Jakub; Zaremba, M.; Maly, M.; Jedelsky, J.; Lizal, F.; Jicha, M.

    2016-06-01

    This article deals with study of airflow under breathing process, which is characteristic by unsteady behavior. Simulations provided by computational fluid dynamics (CFD) was compared with experiments performed on similar geometry of human upper airways. This geometry was represented by mouth cavity of realistic shape connected to an idealized tracheobronchial tree up to fourth generation of branching. Commercial CFD software Star-CCM+ was used to calculate airflow inside investigated geometry and method of Reynolds averaging of Navier-Stokes equations was used for subscribing the turbulent behavior through model geometry. Conditions corresponding to resting state were considered. Comparisons with experiments were provided on several points through trachea and bronchial tree and results with respect to inspiratory and respiratory part of breathing cycle was discussed.

  11. New insights into defibrillation of the heart from realistic simulation studies

    PubMed Central

    Trayanova, Natalia A.; Rantner, Lukas J.

    2014-01-01

    Cardiac defibrillation, as accomplished nowadays by automatic, implantable devices, constitutes the most important means of combating sudden cardiac death. Advancing our understanding towards a full appreciation of the mechanisms by which a shock interacts with the heart, particularly under diseased conditions, is a promising approach to achieve an optimal therapy. The aim of this article is to assess the current state-of-the-art in whole-heart defibrillation modelling, focusing on major insights that have been obtained using defibrillation models, primarily those of realistic heart geometry and disease remodelling. The article showcases the contributions that modelling and simulation have made to our understanding of the defibrillation process. The review thus provides an example of biophysically based computational modelling of the heart (i.e. cardiac defibrillation) that has advanced the understanding of cardiac electrophysiological interaction at the organ level, and has the potential to contribute to the betterment of the clinical practice of defibrillation. PMID:24798960

  12. Analysis of electric and thermal behaviour of lithium-ion cells in realistic driving cycles

    NASA Astrophysics Data System (ADS)

    Tourani, Abbas; White, Peter; Ivey, Paul

    2014-12-01

    A substantial part of electric vehicles (EVs) powertrain is the battery cell. The cells are usually connected in series, and failure of a single cell can deactivate an entire module in the battery pack. Hence, understanding the cell behaviour helps to predict and improve the battery performance and leads to design a cost effective thermal management system for the battery pack. A first principle thermo electrochemical model is applied to study the cell behaviour. The model is in good agreement with the experimental results and can predict the heat generation and the temperature distribution across the cell for different operating conditions. The operating temperature effect on the cell performance is studied and the operating temperature for the best performance is verified. In addition, EV cells are examined in a realistic driving cycle from the Artemis class. The study findings lead to the proposal of some crucial recommendation to design cost effective thermal management systems for the battery pack.

  13. Turbulent transport measurements in a cold model of GT-burner at realistic flow rates

    NASA Astrophysics Data System (ADS)

    Gobyzov, Oleg; Chikishev, Leonid; Lobasov, Alexey; Sharaborin, Dmitriy; Dulin, Vladimir; Bilsky, Artur; Tsatiashvili, Vakhtang; Avgustinovich, Valery; Markovich, Dmitriy

    2016-03-01

    In the present work simultaneous velocity field and passive admixture concentration field measurements at realistic flow-rates conditions in a non-reacting flow in a model of combustion chamber with an industrial mixing device are reported. In the experiments for safety reasons the real fuel (natural gas) was replaced with neon gas to simulate stratification in a strongly swirling flow. Measurements were performed by means of planar laser-induced fluorescence (PLIF) and particle image velocimetry technique (PIV) at Reynolds number, based on the mean flow rate and nozzle diameter, ≈300 000. Details on experimental technique, features of the experimental setup, images and data preprocessing procedures and results of performed measurements are given in the paper. In addition to the raw velocity and admixture concentration data in-depth evaluation approaches aimed for estimation of turbulent kinetic energy (TKE) components, assessment of turbulent Schmidt number and analysis of the gradient closure hypothesis from experimental data are presented in the paper.

  14. Nanomedicine in pulmonary delivery

    PubMed Central

    Mansour, Heidi M; Rhee, Yun-Seok; Wu, Xiao

    2009-01-01

    The lung is an attractive target for drug delivery due to noninvasive administration via inhalation aerosols, avoidance of first-pass metabolism, direct delivery to the site of action for the treatment of respiratory diseases, and the availability of a huge surface area for local drug action and systemic absorption of drug. Colloidal carriers (ie, nanocarrier systems) in pulmonary drug delivery offer many advantages such as the potential to achieve relatively uniform distribution of drug dose among the alveoli, achievement of improved solubility of the drug from its own aqueous solubility, a sustained drug release which consequently reduces dosing frequency, improves patient compliance, decreases incidence of side effects, and the potential of drug internalization by cells. This review focuses on the current status and explores the potential of colloidal carriers (ie, nanocarrier systems) in pulmonary drug delivery with special attention to their pharmaceutical aspects. Manufacturing processes, in vitro/in vivo evaluation methods, and regulatory/toxicity issues of nanomedicines in pulmonary delivery are also discussed. PMID:20054434

  15. RADAR Realistic Animal Model Series for Dose Assessment

    PubMed Central

    Keenan, Mary A.; Stabin, Michael G.; Segars, William P.; Fernald, Michael J.

    2010-01-01

    Rodent species are widely used in the testing and approval of new radiopharmaceuticals, necessitating murine phantom models. As more therapy applications are being tested in animal models, calculating accurate dose estimates for the animals themselves becomes important to explain and control potential radiation toxicity or treatment efficacy. Historically, stylized and mathematically based models have been used for establishing doses to small animals. Recently, a series of anatomically realistic human phantoms was developed using body models based on nonuniform rational B-spline. Realistic digital mouse whole-body (MOBY) and rat whole-body (ROBY) phantoms were developed on the basis of the same NURBS technology and were used in this study to facilitate dose calculations in various species of rodents. Methods Voxel-based versions of scaled MOBY and ROBY models were used with the Vanderbilt multinode computing network (Advanced Computing Center for Research and Education), using geometry and tracking radiation transport codes to calculate specific absorbed fractions (SAFs) with internal photon and electron sources. Photon and electron SAFs were then calculated for relevant organs in all models. Results The SAF results were compared with values from similar studies found in reference literature. Also, the SAFs were used with standardized decay data to develop dose factors to be used in radiation dose calculations. Representative plots were made of photon electron SAFs, evaluating the traditional assumption that all electron energy is absorbed in the source organs. Conclusion The organ masses in the MOBY and ROBY models are in reasonable agreement with models presented by other investigators noting that considerable variation can occur between reported masses. Results consistent with those found by other investigators show that absorbed fractions for electrons for organ self-irradiation were significantly less than 1.0 at energies above 0.5 MeV, as expected for many of

  16. Coupling of realistic rate estimates with genomic for Assessing Contaminant Attenuation and Long-Term Phone

    SciTech Connect

    Colwell, F. S.; Crawford, R. L.; Sorenson, K.

    2003-06-01

    Dissolved dense nonaqueous-phase liquid plumes are persistent, widespread problems in the DOE complex. While perceived as being difficult to degrade, at the Idaho National Engineering and Environmental Laboratory, dissolved trichloroethylene (TCE) is disappearing from the Snake River Plain aquifer (SRPA) by natural attenuation, a finding that saves significant site restoration costs. Acceptance of monitored natural attenuation as a preferred treatment technology requires direct proof of the process and rate of the degradation. Our proposal aims to provide that proof for one such site by testing two hypotheses. First, we believe that realistic values for in situ rates of TCE cometabolism can be obtained by sustaining the putative microorganisms at the low catabolic activities consistent with aquifer conditions. Second, the patterns of functional gene expression evident in these communities under starvation conditions while carrying out TCE cometabolism can be used to diagnose the cometabolic activity in the aquifer itself. Using the cometabolism rate parameters derived in low-growth bioreactors, we will complete the models that predict the time until background levels of TCE are attained at this location and validate the long term stewardship of this plume. Realistic terms for cometabolism of TCE will provide marked improvements in DOE's ability to predict and monitor natural attenuation of chlorinated organics at other sites, increase the acceptability of this solution, and provide significant economic and health benefits through this noninvasive remediation strategy. Finally, this project will derive valuable genomic information about the functional attributes of subsurface microbial communities upon which DOE must depend to resolve some of its most difficult contamination issues.

  17. Nonequilibrium processes from generalized Langevin equations: Realistic nanoscale systems connected to two thermal baths

    NASA Astrophysics Data System (ADS)

    Ness, H.; Genina, A.; Stella, L.; Lorenz, C. D.; Kantorovich, L.

    2016-05-01

    We extend the generalized Langevin equation (GLE) method [L. Stella, C. D. Lorenz, and L. Kantorovich, Phys. Rev. B 89, 134303 (2014), 10.1103/PhysRevB.89.134303] to model a central classical region connected to two realistic thermal baths at two different temperatures. In such nonequilibrium conditions a heat flow is established, via the central system, in between the two baths. The GLE-2B (GLE two baths) scheme permits us to have a realistic description of both the dissipative central system and its surrounding baths. Following the original GLE approach, the extended Langevin dynamics scheme is modified to take into account two sets of auxiliary degrees of freedom corresponding to the mapping of the vibrational properties of each bath. These auxiliary variables are then used to solve the non-Markovian dissipative dynamics of the central region. The resulting algorithm is used to study a model of a short Al nanowire connected to two baths. The results of the simulations using the GLE-2B approach are compared to the results of other simulations that were carried out using standard thermostatting approaches (based on Markovian Langevin and Nosé-Hoover thermostats). We concentrate on the steady-state regime and study the establishment of a local temperature profile within the system. The conditions for obtaining a flat profile or a temperature gradient are examined in detail, in agreement with earlier studies. The results show that the GLE-2B approach is able to treat, within a single scheme, two widely different thermal transport regimes, i.e., ballistic systems, with no temperature gradient, and diffusive systems with a temperature gradient.

  18. Year in Review 2014: Aerosol Delivery Devices.

    PubMed

    Myers, Timothy R

    2015-08-01

    After centuries of discoveries and technological growth, aerosol therapy remains a cornerstone of care in the management of both acute and chronic respiratory conditions. Aerosol therapy embraces the concept that medicine is both an art and a science, where an explicit understanding of the science of aerosol therapy, the nuances of the different delivery devices, and the ability to provide accurate and reliable education to patients become increasingly important. The purpose of this article is to review recent literature regarding aerosol delivery devices in a style that readers of Respiratory Care may use as a key topic resource. PMID:26038596

  19. Transcutaneous antigen delivery system

    PubMed Central

    Lee, Mi-Young; Shin, Meong-Cheol; Yang, Victor C.

    2013-01-01

    Transcutaneous immunization refers to the topical application of antigens onto the epidermis. Transcutaneous immunization targeting the Langerhans cells of the skin has received much attention due to its safe, needle-free, and noninvasive antigen delivery. The skin has important immunological functions with unique roles for antigen-presenting cells such as epidermal Langerhans cells and dermal dendritic cells. In recent years, novel vaccine delivery strategies have continually been developed; however, transcutaneous immunization has not yet been fully exploited due to the penetration barrier represented by the stratum corneum, which inhibits the transport of antigens and adjuvants. Herein we review recent achievements in transcutaneous immunization, focusing on the various strategies for the enhancement of antigen delivery and vaccination efficacy. [BMB Reports 2013; 46(1): 17-24] PMID:23351379

  20. Metrology for drug delivery.

    PubMed

    Lucas, Peter; Klein, Stephan

    2015-08-01

    In various recently published studies, it is argued that there are underestimated risks with infusion technology, i.e., adverse incidents believed to be caused by inadequate administration of the drugs. This is particularly the case for applications involving very low-flow rates, i.e., <1 ml/h and applications involving drug delivery by means of multiple pumps. The risks in infusing are caused by a lack of awareness, incompletely understood properties of the complete drug delivery system and a lack of a proper metrological infrastructure for low-flow rates. Technical challenges such as these were the reason a European research project "Metrology for Drug Delivery" was started in 2011. In this special issue of Biomedical Engineering, the results of that project are discussed. PMID:25879307

  1. Will Realistic Fossil Fuel Burning Scenarios Prevent Catastrophic Climate Change?

    NASA Astrophysics Data System (ADS)

    Tans, P. P.; Rutledge, D.

    2012-12-01

    In the IPCC Special Report on Emissions Scenarios the driving forces are almost entirely demographic and socio-economic, with scant attention given to potential resource limitations. In a recent study D. Rutledge (2011) shows that in the case of historical coal production, a stable estimate, typically much lower than early estimates of reserves, of total long term production of a region can be obtained well before peak production is reached based on actual production numbers until that point. The estimates are based on produced quantities only, and appear to contradict the assumption of dominant control by socio-economic factors and improvements in technology. Therefore, a projection of climate forcing based on a emissions scenario close to the lowest of the IPCC scenarios may be more realistic. The longevity of the CO2 enhancement in the atmosphere and oceans is thousands of years. The partitioning of the CO2 enhancement between atmosphere and oceans, and thus climate forcing by CO2, is calculated until the year 2500. The fundamental difficulty of CO2 removal strategies is pointed out. The integral of climate forcing until 2500 under a low emissions scenario is still so large that climate change may become an impediment to human development in addition to higher energy costs. D. Rutledge, International J. Coal Geology 85, 23-33 (2011).

  2. Evolution of migration rate in a spatially realistic metapopulation model.

    PubMed

    Heino, M; Hanski, I

    2001-05-01

    We use an individual-based, spatially realistic metapopulation model to study the evolution of migration rate. We first explore the consequences of habitat change in hypothetical patch networks on a regular lattice. If the primary consequence of habitat change is an increase in local extinction risk as a result of decreased local population sizes, migration rate increases. A nonmonotonic response, with migration rate decreasing at high extinction rate, was obtained only by assuming very frequent catastrophes. If the quality of the matrix habitat deteriorates, leading to increased mortality during migration, the evolutionary response is more complex. As long as habitat patch occupancy does not decrease markedly with increased migration mortality, reduced migration rate evolves. However, once mortality becomes so high that empty patches remain uncolonized for a long time, evolution tends to increase migration rate, which may lead to an "evolutionary rescue" in a fragmented landscape. Kin competition has a quantitative effect on the evolution of migration rate in our model, but these patterns in the evolution of migration rate appear to be primarily caused by spatiotemporal variation in fitness and mortality during migration. We apply the model to real habitat patch networks occupied by two checkerspot butterfly (Melitaea) species, for which sufficient data are available to estimate rigorously most of the model parameters. The model-predicted migration rate is not significantly different from the empirically observed one. Regional variation in patch areas and connectivities leads to regional variation in the optimal migration rate, predictions that can be tested empirically. PMID:18707258

  3. Time-distance helioseismology of two realistic sunspot simulations

    SciTech Connect

    DeGrave, K.; Jackiewicz, J.; Rempel, M. E-mail: jasonj@nmsu.edu

    2014-10-10

    Linear time-distance helioseismic inversions are carried out using several filtering schemes to determine vector flow velocities within two ∼100{sup 2} Mm{sup 2} × 20 Mm realistic magnetohydrodynamic sunspot simulations of 25 hr. One simulation domain contains a model of a full sunspot (i.e., one with both an umbra and penumbra), while the other contains a pore (i.e., a spot without a penumbra). The goal is to test current helioseismic methods using these state-of-the-art simulations of magnetic structures. We find that horizontal flow correlations between inversion and simulation flow maps are reasonably high (∼0.5-0.8) in the upper 3 Mm at distances exceeding 25-30 Mm from spot center, but are substantially lower at smaller distances and larger depths. Inversions of forward-modeled travel times consistently outperform those of our measured travel times in terms of horizontal flow correlations, suggesting that our inability to recover flow structure near these active regions is largely due to the fact that we are unable to accurately measure travel times near strong magnetic features. In many cases the velocity amplitudes from the inversions underestimate those of the simulations by up to 50%, possibly indicating nonlinearity of the forward problem. In every case, we find that our inversions are unable to recover the vertical flow structure of the simulations at any depth.

  4. Realistic Modeling of Spontaneous Flow Eruptions in the Quiet Sun

    NASA Astrophysics Data System (ADS)

    Kitiashvili, Irina; Yoon, Seokkwan S

    2014-06-01

    Ground and space observations reveal that the solar surface is covered by high-speed jets transporting mass and energy into the solar corona and feeding the solar wind. The origin and driving forces of the observed eruptions are still unknown. Using realistic numerical simulations we find that small-scale plasma eruptions can be produced by ubiquitous magnetized vortex tubes generated in the Sun's turbulent convection. The vortex tubes (resembling tornadoes) penetrate into the solar atmosphere, capture and strengthen the background magnetic field, and push surrounding material up, generating impulses of Alfven waves and shocks. Our simulations reveal complicated high-speed flows, thermodynamic, and magnetic structures in the erupting vortex tubes. We find that the eruptions are initiated in the subsurface layers, and initially are driven by high-pressure gradients in the subphotosphere and photosphere, and are accelerated by the Lorentz force in the higher atmospheric layers. The eruptions are often quasi-periodic with a characteristic period of 2-5 min. These vortex eruptions have a complicated flow helical pattern, with predominantly downward flows in the vortex tube cores and upward flows in their surroundings. For comparison with observations we calculate full Stokes profiles in different wavelength for different space and ground instruments, such as HMI/SDO, Hinode, NST/BBSO, IMaX/Sunrise. In particular, we find that the observed eruption events are not always associated with strong magnetic field concentrations, and that strong field patches can be a source of several simultaneous eruptions.

  5. Adaptive self-organization in a realistic neural network model

    NASA Astrophysics Data System (ADS)

    Meisel, Christian; Gross, Thilo

    2009-12-01

    Information processing in complex systems is often found to be maximally efficient close to critical states associated with phase transitions. It is therefore conceivable that also neural information processing operates close to criticality. This is further supported by the observation of power-law distributions, which are a hallmark of phase transitions. An important open question is how neural networks could remain close to a critical point while undergoing a continual change in the course of development, adaptation, learning, and more. An influential contribution was made by Bornholdt and Rohlf, introducing a generic mechanism of robust self-organized criticality in adaptive networks. Here, we address the question whether this mechanism is relevant for real neural networks. We show in a realistic model that spike-time-dependent synaptic plasticity can self-organize neural networks robustly toward criticality. Our model reproduces several empirical observations and makes testable predictions on the distribution of synaptic strength, relating them to the critical state of the network. These results suggest that the interplay between dynamics and topology may be essential for neural information processing.

  6. A realistic 3+1D Viscous Hydro Algorithm

    SciTech Connect

    Romatschke, Paul

    2015-05-31

    DoE funds were used as bridge funds for the faculty position for the PI at the University of Colorado. The total funds for the Years 3-5 of the JET Topical Collaboration amounted to about 50 percent of the academic year salary of the PI.The PI contributed to the JET Topical Collaboration by developing, testing and applying algorithms for a realistic simulation of the bulk medium created in relativistic ion collisions.Specifically, two approaches were studied, one based on a new Lattice-Boltzmann (LB) framework, and one on a more traditional viscous hydro-dynamics framework. Both approaches were found to be viable in principle, with the LB approach being more elegant but needing still more time to develop.The traditional approach led to the super-hybrid model of ion collisions dubbed 'superSONIC', and has been successfully used for phenomenology of relativistic heavy-ion and light-on-heavy-ion collisions.In the time-frame of the JET Topical Collaboration, the Colorado group has published 15 articles in peer-reviewed journals, three of which were published in Physical Review Letters. The group graduated one Master student during this time-frame and two more PhD students are expected to graduate in the next few years. The PI has given more than 28 talks and presentations during this period.

  7. 'Narrative', now and then: a critical realist approach.

    PubMed

    Hanly, M F

    1996-06-01

    The author argues that the idea of a 'narrative approach' in psychoanalysis has come to imply that the history of the psyche of a patient is inaccessible and that what the analyst should aim to achieve is the co-construction of a 'story' agreed to by both analyst and patient. She examines some critical realist views on narrative that engage with the problem of how the past determines story-telling in the present. The narrative-hermeneutic perspective has emphasised how much a telling is shaped by the transference, in order, it seems, to urge analysts to forgo a 'naïve realism', an attempt to get at some 'bare facts' of the past, which would lose the bearing of much the patient is communicating in the present. This, as a technical reminder, is excellent. However, critical realism in psychoanalysis has always been sophisticated as opposed to naïve, because of our concern with the workings of oedipal and post-oedipal transformations, and with the workings of the transference. It is the thesis of this paper, written from the perspective of critical realism, that every interpretation, in so far as it contains a narrative truth, that is, speaks adequately of coherence and transference issues, will also refer to a significant aspect of the history of the patient's psyche. PMID:8818763

  8. Simulation of Combustion Systems with Realistic g-Jitter

    NASA Technical Reports Server (NTRS)

    Mell, W. E.; McGrattan, K. B.; Nakamura, Y.; Baum, H. R.

    2001-01-01

    A number of facilities are available for microgravity combustion experiments: aircraft, drop towers, sounding rockets, the space shuttle, and, in the future, the International Space Station (ISS). Acceleration disturbances or g-jitter about the background level of reduced gravity exist in all these microgravity facilities. While g-jitter is routinely measured, a quantitative comparison of the quality of g-jitter among the different microgravity facilities, in terms of its affects on combustion experiments, has not been compiled. Low frequency g-jitter (< 1 Hz) has been repeatedly observed to disturb a number of combustion systems. Guidelines regarding tolerable levels of acceleration disturbances for combustion experiments have been developed for use in the design of ISS experiments. The validity of these guidelines, however, remains unknown. In this project a transient, 3-D numerical model is under development to simulate the effects of realistic g-jitter on a number of combustion systems. The measured acceleration vector or some representation of it can be used as input to the simulation.

  9. A computational study of routing algorithms for realistic transportation networks

    SciTech Connect

    Jacob, R.; Marathe, M.V.; Nagel, K.

    1998-12-01

    The authors carry out an experimental analysis of a number of shortest path (routing) algorithms investigated in the context of the TRANSIMS (Transportation Analysis and Simulation System) project. The main focus of the paper is to study how various heuristic and exact solutions, associated data structures affected the computational performance of the software developed especially for realistic transportation networks. For this purpose the authors have used Dallas Fort-Worth road network with very high degree of resolution. The following general results are obtained: (1) they discuss and experimentally analyze various one-one shortest path algorithms, which include classical exact algorithms studied in the literature as well as heuristic solutions that are designed to take into account the geometric structure of the input instances; (2) they describe a number of extensions to the basic shortest path algorithm. These extensions were primarily motivated by practical problems arising in TRANSIMS and ITS (Intelligent Transportation Systems) related technologies. Extensions discussed include--(i) time dependent networks, (ii) multi-modal networks, (iii) networks with public transportation and associated schedules. Computational results are provided to empirically compare the efficiency of various algorithms. The studies indicate that a modified Dijkstra`s algorithm is computationally fast and an excellent candidate for use in various transportation planning applications as well as ITS related technologies.

  10. Beam tracking of SXLS with realistic magnetic field

    SciTech Connect

    Huang, Yun-Xiang

    1991-09-01

    In early 1977, while working for NSLS at Brookhaven National Lab., Dr. Ohnuma noticed that tunes of NSLS calculated with code SYNCH were significantly different from those obtained with code PATRICIA. This problem surfaced again in 1991 when people at BNL discovered discrepancies in their compact ring SXLS chromaticities calculated with different code. One potential source of the ambiguities is the different treatment of the edge field and the combined function field of dipole magnet. There are two dipoles each of which with the bending angle of 180{degrees} instead of at most a few degrees which is common in high energy synchrotrons. The calculation of a three-dimensional field using TOSCA indicates that the fringe field extends to cover the whole region between the dipole and the quadrupole, having a vertical field strength of 250 gauss at the edge of the quadrupole. In this case, the fringe multiple field will undoubtedly play a nontrival role in determining basic machine parameters. Therefore, the classical treatment for simulating particle motion in synchrotron, which uses the isomagnetic approximation plus then lens kicks, no longer accurately models the closed orbit of the machine. In order to correctly calculate tunes, chromaticities as well as the dynamic aperture in such kind of machine with a large magnetic bending angle, it is necessary to integrate the exact equations of motion in a realistic representation of the magnetic field.

  11. Realistic Low-Momentum Nucleon-Nucleon Potential

    NASA Astrophysics Data System (ADS)

    Kuo, T. T. S.; Bogner, S. K.; Coraggio, L.; Covello, A.; Itaco, N.

    2002-04-01

    A low-momentum nucleon-nucleon (NN) potential Vlow-k is derived from modern realistic NN potentials VNN by integrating out their high momentum modes. The Kuo-Lee-Ratcliff folded diagram method together with the Andreozzi-Lee-Suzuki iteration method is employed to carry out the integration. Our Vlow-k is confined within a cut-off momentum Λ, and it preserves the deuteron binding energy, low-energy phase shifts and low-momentum half-on-shell T-matrix of VNN. For Λ within ~ 2fm-1, the Vlow-k derived from various NN potential models are very close to each other, although these models themselves are very different. Vlow-k is a smooth potential for Λ in the vicinity 2fm-1, and appears to be suitable for being used directly as shell model effective interaction without first calculating the Brueckner G matrix. Preliminary shell-model calculations using Vlow-k have led to encouraging results.

  12. Is there hope for spintronics in one dimensional realistic systems?

    NASA Astrophysics Data System (ADS)

    Rocha, Alexandre; Martins, Thiago; Fazzio, Adalberto; da Silva, Antônio J. R.

    2010-03-01

    The use of the electron spin as the ultimate logic bit can lead to a novel way of thinking about information flow. At the same time graphene, a gapless semiconductor, has been the subject of intense research due to its fundamental properties and its potential application in electronics. Defects are usually seen as having deleterious effects on the spin polarization of devices and thus they would tend to hinder the applicability of spintronics in realistic devices. Here we use a ab initio methods to simulate the electronic transport properties of graphene nanoribbons up to 450 nm long containing a large number of randomly distributed impurities. We will demonstrate that it is possible to obtain perfect spin selectivity in these nanoribbons which can be explained in terms of different localization lengths for each spin channel. This together with the well know exponential dependence of the conductance on the length of the device leads to a new mechanism for the spin filtering effect that is in fact driven by disorder. Furthermore, we demonstrate that this is an effect that does not depend on the underlying system itself and could be observed in carbon nanotubes and nanowires or any other one-dimensional device.

  13. Promoting nutrition in commercial foodservice establishments: a realistic approach.

    PubMed

    Regan, C

    1987-04-01

    Americans are eating out an average of 3.7 times per week and are spending almost 40% of their food dollar doing so. A Gallup Survey shows about 39% of consumers claim to have improved their eating habits while eating out, but restaurant patrons are most concerned about nutrition when dining out on a routine visit or while in a family-style restaurant. Restaurant patrons are also now more likely to order lower sodium meals, small-size portions, and lower calorie entrées. Although the opportunity to promote nutrition in the foodservice setting exists, restaurant chefs and managers often lack the background to take advantage of it and could benefit from the services of qualified nutrition professionals. Dietitians could assist in identifying menu items appropriate for nutrition promotion, recipe development, and staff training. However, a realistic approach must be maintained, and the following facts should be kept in mind: Nutritious restaurant fare should blend with the theme of the menu and be promoted primarily on its sensory attributes. Nutrition in restaurants is best received when promoted generally and within the scope of health and wellness. Descriptive menu items should be carefully used. A restaurant consultant should be current on controversial food and nutrition trends. The wait staff should be properly trained. PMID:3559009

  14. Effects of angular confinement and concentration to realistic solar cells

    SciTech Connect

    Höhn, O. Kraus, T.; Bläsi, B.; Schwarz, U. T.

    2015-01-21

    In standard solar cells, light impinges under a very small angular range, whereas the solar cell emits light into the whole half space. Due to this expansion of etendué, entropy is generated, which limits the maximal efficiency of solar cells. This limit can be overcome by either increasing the angle of incidence by concentration or by decreasing the angle of emission by an angularly confining element or by a combination of both. In an ideal solar cell with radiative recombination as the only loss mechanism, angular confinement and concentration are thermodynamically equivalent. It is shown that concentration in a device, where non-radiative losses such as Shockley-Read-Hall and Auger recombination are considered, is not equivalent to angular confinement. As soon as non-radiative losses are considered, the gain in efficiency due to angular confinement drops significantly in contrast to the gain caused by concentration. With the help of detailed balance calculations, it is furthermore shown that angular confinement can help to increase the efficiency of solar cells under concentrated sunlight even if no measurable gain is expected for the solar cell under 1-sun-illumination. Our analysis predicts a relative gain of 3.14% relative in efficiency for a realistic solar cell with a concentration factor of 500.

  15. A simple and realistic model of supersymmetry breaking

    SciTech Connect

    Nomura, Yasunori; Papucci, Michele

    2007-09-25

    We present a simple and realistic model of supersymmetry breaking. In addition to the minimal supersymmetric standard model, we only introduce a hidden sector gauge group SU(5) and three fields X, F and \\bar{F}. Supersymmetry is broken at a local minimum of the potential, and its effects are transmitted to the supersymmetric standard model sector through both standard model gauge loops and local operators suppressed by the cutoff scale, which is taken to be the unification scale. The form of the local operators is controlled by a U(1) symmetry. The generated supersymmetry breaking and mu parameters are comparable in size, and no flavor or CP violating terms arise. The spectrum of the first two generation superparticles is that of minimal gauge mediation with the number of messengers N_mess = 5 and the messenger scale 1011 GeV< M_mess< 1013 GeV. The spectrum of the Higgs bosons and third generation superparticles, however, can deviate from it. The lightest supersymmetric particle is the gravitino with a mass of order (1-10) GeV.

  16. High Energy Atmospheric Neutrino Fluxes From a Realistic Primary Spectrum

    NASA Astrophysics Data System (ADS)

    Campos Penha, Felipe; Dembinski, Hans; Gaisser, Thomas K.; Tilav, Serap

    2016-03-01

    Atmospheric neutrino fluxes depend on the energy spectrum of primary nucleons entering the top of the atmosphere. Before the advent of AMANDA and the IceCube Neutrino Observatory, measurements of the neutrino fluxes were generally below ~ 1TeV , a regime in which a simple energy power law sufficed to describe the primary spectrum. Now, IceCube's muon neutrino data extends beyond 1PeV , including a combination of neutrinos from astrophysical sources with background from atmospheric neutrinos. At such high energies, the steepening at the knee of the primary spectrum must be accounted for. Here, we describe a semi-analytical approach for calculating the atmospheric differential neutrino fluxes at high energies. The input is a realistic primary spectrum consisting of 4 populations with distinct energy cutoffs, each with up to 7 representative nuclei, where the parameters were extracted from a global fit. We show the effect of each component on the atmospheric neutrino spectra, above 10TeV . The resulting features follow directly from recent air shower measurements included in the fit. Felipe Campos Penha gratefully acknowledges financial support from CAPES (Processo BEX 5348/14-5), CNPq (Processo 142180/2012-2), and the Bartol Research Institute.

  17. Improved transcranial magnetic stimulation coil design with realistic head modeling

    NASA Astrophysics Data System (ADS)

    Crowther, Lawrence; Hadimani, Ravi; Jiles, David

    2013-03-01

    We are investigating Transcranial magnetic stimulation (TMS) as a noninvasive technique based on electromagnetic induction which causes stimulation of the neurons in the brain. TMS can be used as a pain-free alternative to conventional electroconvulsive therapy (ECT) which is still widely implemented for treatment of major depression. Development of improved TMS coils capable of stimulating subcortical regions could also allow TMS to replace invasive deep brain stimulation (DBS) which requires surgical implantation of electrodes in the brain. Our new designs allow new applications of the technique to be established for a variety of diagnostic and therapeutic applications of psychiatric disorders and neurological diseases. Calculation of the fields generated inside the head is vital for the use of this method for treatment. In prior work we have implemented a realistic head model, incorporating inhomogeneous tissue structures and electrical conductivities, allowing the site of neuronal activation to be accurately calculated. We will show how we utilize this model in the development of novel TMS coil designs to improve the depth of penetration and localization of stimulation produced by stimulator coils.

  18. GRACE follow-on sensor noise with realistic background models

    NASA Astrophysics Data System (ADS)

    Ellmer, Matthias; Mayer-Gürr, Torsten

    2015-04-01

    We performed multiple simulation studies of a GRACE-like satellite mission based on the current K-Band ranging instrument (KBR). We also simulated a laser-ranging instrument (LRI) configuration as a drop-in replacement for GRACE low-low satellite to satellite tracking, the remaining parameters of the simulation are shared between the two scenarios. Our simulated data are based on real GRACE observations for April 2006, which allows us to compare our results to published gravity field models for this particular month. The variational equation approach was employed to generate independent reduced-dynamic orbits for both GRACE satellites. These orbits were then fitted to the actual GRACE kinematic orbits. The resulting orbit was then used to synthesize artificial satellite ranging, star camera, accelerometer and kinematic orbit data. We synchronized all simulated instruments with real instrument data for the simulated month, which guarantees realistic data gaps. Appropriate noise was added to all observables. In the recovery step, the AOD1B de-aliasing product -- previously used in the generation of the fundamental reduced-dynamic orbit data -- was degraded with partial constituents of the updated ESA earth system model dataset. Specifically, the atmosphere, ocean, and hydrology components were used. This has the effect that the computed gravity field possesses the characteristic structure associated with a residual time-variable gravity field signal. An overview of the achieved results is given in the presentation.

  19. Karstification beneath dam sites: From conceptual models to realistic scenarios

    NASA Astrophysics Data System (ADS)

    Hiller, Thomas; Kaufmann, Georg; Romanov, Douchko

    2010-05-01

    Dam sites located above soluble rock such as limestone or gypsum can leak in relatively short times (tenths of years), when compared to the natural time scale of karstification (10.000-100.000 years). The reason for this leakage is the high hydraulic gradient imposed by the reservoir that drives aggressive water through the fracture and fissure system of the bedrock and this aggressive water dissolves the rock and increases permeability fairly fast. Thus, on the one hand water losses through enlarged fractures can become a problem for the reservoir. On the other hand, the void space itself can be a risk for the dam structure above. This may have unpredictable ecological and economical consequences. We present a three-dimensional conceptual model study of karstification in dam-site areas on limestone bedrock. We compare our three-dimensional model to a standard two-dimensional dam site model to verify the results of our code. We further carry out a sensitivity analysis on the physical and chemical parameters driving the karstification to derive an empirical formulation of the breakthrough time TB. In a next step we implement a statistical fracture network and topography to approach a more realistic scenario. Finally we show the results of a three dimensional model based on a real dam site.

  20. Reconstruction of spatial qutrit states based on realistic measurement operators

    SciTech Connect

    Taguchi, Gen; Dougakiuchi, Tatsuo; Iinuma, Masataka; Hofmann, Holger F.; Kadoya, Yutaka

    2009-12-15

    Spatial qudit states can be realized by using multislits to discretize the transverse momentum of a photon. The merit of this kind of spatial qudit states is that the implementation of higher-dimensional qudits is relatively easy. As we have recently shown, the quantum states of these spatial qudits can be analyzed by scanning a single interference pattern. This method of single scan tomography can also be applied at higher dimensions, but the reconstruction becomes more sensitive to smaller details of the scanned patterns as the dimensions increase. In this paper, we investigate the effect of finite measurement resolution on the single scan tomography of spatial qutrits. Realistic measurement operators describing the spatial resolution of the measurement are introduced and the corresponding pattern functions for quantum state reconstruction are derived. We use the pattern functions to analyze experimental results for entangled pairs of spatial qutrits generated by spontaneous parametric downconversion. It is shown that a reliable reconstruction of the quantum state can be achieved with finite measurement resolution if this limitation of the measurement is included in the pattern functions of single scan tomography.

  1. A Simple, Realistic Stochastic Model of Gastric Emptying

    PubMed Central

    Yokrattanasak, Jiraphat; De Gaetano, Andrea; Panunzi, Simona; Satiracoo, Pairote; Lawton, Wayne M.; Lenbury, Yongwimon

    2016-01-01

    Several models of Gastric Emptying (GE) have been employed in the past to represent the rate of delivery of stomach contents to the duodenum and jejunum. These models have all used a deterministic form (algebraic equations or ordinary differential equations), considering GE as a continuous, smooth process in time. However, GE is known to occur as a sequence of spurts, irregular both in size and in timing. Hence, we formulate a simple stochastic process model, able to represent the irregular decrements of gastric contents after a meal. The model is calibrated on existing literature data and provides consistent predictions of the observed variability in the emptying trajectories. This approach may be useful in metabolic modeling, since it describes well and explains the apparently heterogeneous GE experimental results in situations where common gastric mechanics across subjects would be expected. PMID:27057750

  2. Implementation of Antiretroviral Therapy Adherence Interventions: A Realist Synthesis of Evidence

    PubMed Central

    Leeman, Jennifer; Chang, Yun Kyung; Lee, EunJeong; Voils, Corrine I.; Sandelowski, Margarete

    2010-01-01

    Aim This paper is a report of a synthesis of evidence on implementation of interventions to improve adherence to antiretroviral therapy. Background Evidence on efficacy must be supplemented with evidence on how interventions were implemented in practice and on how that implementation varied across populations and settings. Data Sources Sixty-one reports were reviewed of studies conducted in the United States of America in the period 2001 to December 2008. Fifty-two reports were included in the final analysis: 37 reporting the effects of interventions and 15 reporting intervention feasibility, acceptability, or fidelity. Review Methods An adaptation of Pawson’s realist synthesis method was used, whereby a provisional explanatory model and associated list of propositions are developed from an initial review of literature. This model is successively refined to the point at which it best explains empirical findings from the reports reviewed. Results The final explanatory model suggests that individuals with HIV will be more likely to enrol in interventions that protect their confidentiality, to attend when scheduling is responsive to their needs, and both to attend and continue with an intervention when they develop a strong, one-to-one relationship with the intervener. Participants who have limited prior experience with antiretroviral therapy will be more likely to continue with an intervention than those who are more experienced. Dropout rates are likely to be higher when interventions are integrated into existing delivery systems than when offered as stand-alone interventions. Conclusion The explanatory model developed in this study is intended to provide guidance to clinicians and researchers on the points in the implementation chain that require strengthening. PMID:20707822

  3. The organisation of interagency training to safeguard children in England: a case study using realistic evaluation

    PubMed Central

    Patsios, Demi; Carpenter, John

    2010-01-01

    Background Joint training for interagency working is carried out by Local Safeguarding Children Boards in England to promote effective local working to safeguard and promote the welfare of children. Purpose This paper reports on the findings of the outputs and outcomes of interagency training to safeguard children in eight Local Safeguarding Children Boards. Methods A review of Local Safeguarding Children Board documentation, observations of Local Safeguarding Children Board training sub-group meetings and a series of interviews with training key stakeholders in each Local Safeguarding Children Board were used to assess how partner agencies in the Local Safeguarding Children Boards carried out their statutory responsibilities to organise interagency training. ‘Realistic Evaluation’ was used to evaluate the mechanisms by which a central government mandate produced particular inter-agency training outputs (number of courses, training days) and joint working outcomes (effective partnerships), within particular Local Safeguarding Children Board contexts. Results The ‘mandated partnership’ imposed on Local Safeguarding Children Boards by central government left little choice but for partner agencies to work together to deliver joint training, which in turn affected the dynamics of working partnerships across the various sites. The effectiveness of the training sub group determined the success of the organisation and delivery of training for joint working. Despite having a central mandate, Local Safeguarding Children Boards had heterogeneous funding and training arrangements. These resulted in significant variations in the outputs in terms of the number of courses per ‘children in need’ in the locality and in the cost per course. Conclusions Interagency training which takes account of the context of the Local Safeguarding Children Board is more likely to produce better trained staff, effective partnership working, and lead to better integrated safeguarding

  4. Delayed interval delivery in a triplet gestation

    PubMed Central

    Wooldridge, Rachel J; Oliver, Emily A; Singh, Tulika

    2012-01-01

    A 27-year-old Ghanaian primigravida with a known triamniotic trichorionic triplet pregnancy presented at 17 weeks gestation following a miscarriage of one triplet at home. Examination and investigation revealed no signs of imminent delivery or infection. After careful counselling with regard to prognosis and options available for management, the couple opted for intervention including rescue cerclage. The patient received antibiotic prophylaxis for five days and daily progesterone suppositories until delivery. An ultrasound scan was performed every three weeks to monitor fetal growth and cervical length. At 24 weeks corticosteroids for fetal lung maturity were given. At 31 weeks gestation she experienced spontaneous rupture of membranes followed by active labour and forceps delivery. There were no maternal complications. Both babies were born in a good condition, but required ventilatory support for 72 h. PMID:23188854

  5. Targeted delivery of therapeutics to endothelium

    PubMed Central

    Simone, Eric; Ding, Bi-Sen

    2009-01-01

    The endothelium is a target for therapeutic and diagnostic interventions in a plethora of human disease conditions including ischemia, inflammation, edema, oxidative stress, thrombosis and hemorrhage, and metabolic and oncological diseases. Unfortunately, drugs have no affinity to the endothelium, thereby limiting the localization, timing, specificity, safety, and effectiveness of therapeutic interventions. Molecular determinants on the surface of resting and pathologically altered endothelial cells, including cell adhesion molecules, peptidases, and receptors involved in endocytosis, can be used for drug delivery to the endothelial surface and into intracellular compartments. Drug delivery platforms such as protein conjugates, recombinant fusion constructs, targeted liposomes, and stealth polymer carriers have been designed to target drugs and imaging agents to these determinants. We review endothelial target determinants and drug delivery systems, describe parameters that control the binding of drug carriers to the endothelium, and provide examples of the endothelial targeting of therapeutic enzymes designed for the treatment of acute vascular disorders including ischemia, oxidative stress, inflammation, and thrombosis. PMID:18815813

  6. Systems and Components Fuel Delivery System, Water Delivery System, ...

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

    Systems and Components - Fuel Delivery System, Water Delivery System, Derrick Crane System, and Crane System Details - Marshall Space Flight Center, F-1 Engine Static Test Stand, On Route 565 between Huntsville and Decatur, Huntsville, Madison County, AL

  7. Improving skills and care standards in the support workforce for older people: a realist synthesis of workforce development interventions

    PubMed Central

    Williams, L; Rycroft-Malone, J; Burton, C R; Edwards, S; Fisher, D; Hall, B; McCormack, B; Nutley, S M; Seddon, D; Williams, R

    2016-01-01

    Objectives This evidence review was conducted to understand how and why workforce development interventions can improve the skills and care standards of support workers in older people's services. Design Following recognised realist synthesis principles, the review was completed by (1) development of an initial programme theory; (2) retrieval, review and synthesis of evidence relating to interventions designed to develop the support workforce; (3) ‘testing out’ the synthesis findings to refine the programme theories, and establish their practical relevance/potential for implementation through stakeholder interviews; and (4) forming actionable recommendations. Participants Stakeholders who represented services, commissioners and older people were involved in workshops in an advisory capacity, and 10 participants were interviewed during the theory refinement process. Results Eight context–mechanism–outcome (CMO) configurations were identified which cumulatively comprise a new programme theory about ‘what works’ to support workforce development in older people's services. The CMOs indicate that the design and delivery of workforce development includes how to make it real to the work of those delivering support to older people; the individual support worker's personal starting points and expectations of the role; how to tap into support workers' motivations; the use of incentivisation; joining things up around workforce development; getting the right mix of people engaged in the design and delivery of workforce development programmes/interventions; taking a planned approach to workforce development, and the ways in which components of interventions reinforce one another, increasing the potential for impacts to embed and spread across organisations. Conclusions It is important to take a tailored approach to the design and delivery of workforce development that is mindful of the needs of older people, support workers, health and social care services and the

  8. "Programmed packaging" for gene delivery.

    PubMed

    Hyodo, M; Sakurai, Y; Akita, H; Harashima, H

    2014-11-10

    We report on the development of a multifunctional envelope-type nano device (MEND) based on our packaging concept "Programmed packaging" to control not only intracellular trafficking but also the biodistribution of encapsulated compounds such as nucleic acids/proteins/peptides. Our strategy for achieving this is based on molecular mechanisms of cell biology such as endocytosis, vesicular trafficking, etc. In this review, we summarize the concept of programmed packaging and discuss some of our recent successful examples of using MENDs. Systematic evolution of ligands by exponential enrichment (SELEX) was applied as a new methodology for identifying a new ligand toward cell or mitochondria. The delivery of siRNA to tumors and the tumor vasculature was achieved using pH sensitive lipid (YSK05), which was newly designed and optimized under in vivo conditions. The efficient delivery of pDNA to immune cells such as dendritic cells has also been developed using the KALA ligand, which can be a breakthrough technology for DNA vaccine. Finally, ss-cleavable and pH-activated lipid-like surfactant (ssPalm) which is a lipid like material with pH-activatable and SS-cleavable properties is also introduced as a proof of our concept. PMID:24780263

  9. The boundary layer over turbine blade models with realistic rough surfaces

    NASA Astrophysics Data System (ADS)

    McIlroy, Hugh M., Jr.

    The impact of turbine blade surface roughness on aerodynamic performance and heat loads is well known. Over time, as the turbine blades are exposed to heat loads, the external surfaces of the blades become rough. Also, for film-cooled blades, surface degradation can have a significant impact on film-cooling effectiveness. Many studies have been conducted on the effects of surface degradation/roughness on engine performance but most investigations have modeled the rough surfaces with uniform or two-dimensional roughness patterns. The objective of the present investigation is to conduct measurements that will reveal the influence of realistic surface roughness on the near-wall behavior of the boundary layer. Measurements have been conducted at the Matched-Index-of-Refraction (MIR) Facility at the Idaho National Engineering and Environmental Laboratory with a laser Doppler velocimeter. A flat plate model of a turbine blade has been developed that produces a transitional boundary layer, elevated freestream turbulence and an accelerating freestream in order to simulate conditions on the suction side of a high-pressure turbine blade. Boundary layer measurements have been completed over a smooth plate model and over a model with a strip of realistic rough surface. The realistic rough surface was developed by scaling actual turbine blade surface data that was provided by U.S. Air Force Research Laboratory. The results indicate that bypass transition occurred very early in the flow over the model and that the boundary layer remained unstable throughout the entire length of the test plate; the boundary layer thickness and momentum thickness Reynolds numbers increased over the rough patch; and the shape factor increased over the rough patch but then decreased downstream of the patch relative to the smooth plate case; in the rough patch case the flow experienced two transition reversals with laminar-like behavior achieved by the end of the test plate; streamwise turbulence

  10. Realistic Goals and Processes for Future Space Astronomy Portfolio Planning

    NASA Astrophysics Data System (ADS)

    Morse, Jon

    2015-08-01

    It is generally recognized that international participation and coordination is highly valuable for maximizing the scientific impact of modern space science facilities, as well as for cost-sharing reasons. Indeed, all large space science missions, and most medium and small missions, are international, even if one country or space agency has a clear leadership role and bears most of the development costs. International coordination is a necessary aspect of future mission planning, but how that coordination is done remains debatable. I propose that the community's scientific vision is generally homogeneous enough to permit international coordination of decadal-scale strategic science goals. However, the timing and budget allocation/funding mechanisms of individual countries and/or space agencies are too disparate for effective long-term strategic portfolio planning via a single international process. Rather, I argue that coordinated space mission portfolio planning is a natural consequence of international collaboration on individual strategic missions. I review the process and outcomes of the U.S. 2010 decadal survey in astronomy & astrophysics from the perspective of a government official who helped craft the survey charter and transmitted guidance to the scientific community on behalf of a sponsoring agency (NASA), while continuing to manage the current portfolio that involved ongoing negotiations with other space agencies. I analyze the difficulties associated with projecting long-term budgets, obtaining realistic mission costs (including the additional cost burdens of international partnerships), and developing new (possibly transformational) technologies. Finally, I remark on the future role that privately funded space science missions can have in accomplishing international science community goals.

  11. Realistic weather simulations and forecast verification with COSMO-EULAG

    NASA Astrophysics Data System (ADS)

    Wójcik, Damian; Piotrowski, Zbigniew; Rosa, Bogdan; Ziemiański, Michał

    2015-04-01

    Research conducted at Polish Institute of Meteorology and Water Management, National Research Institute, in collaboration with Consortium for Small Scale Modeling (COSMO) resulted in the development of a new prototype model COSMO-EULAG. The dynamical core of the new model is based on anelastic set of equation and numerics adopted from the EULAG model. The core is coupled, with the 1st degree of accuracy, to the COSMO physical parameterizations involving turbulence, friction, radiation, moist processes and surface fluxes. The tool is capable to compute weather forecast in mountainous area for the horizontal resolutions ranging from 2.2 km to 0.1 km and with slopes reaching 82 degree of inclination. An employment of EULAG allows to profit from its desirable conservative properties and numerical robustness confirmed in number of benchmark tests and widely documented in scientific literature. In this study we show a realistic case study of Alpine summer convection simulated by COSMO-EULAG. It compares the convection-permitting realization of the flow using 2.2 km horizontal grid size, typical for contemporary very high resolution regional NWP forecast, with realization of LES type using grid size of 100 m. The study presents comparison of flow, cloud and precipitation structure together with the reference results of standard compressible COSMO Runge-Kutta model forecast in 2.2 km horizontal resolution. The case study results are supplemented by COSMO-EULAG forecast verification results for Alpine domain in 2.2 km horizontal resolution. Wind, temperature, cloud, humidity and precipitation scores are being presented. Verification period covers one summer month (June 2013) and one autumn month (November 2013). Verification is based on data collected by a network of approximately 200 stations (surface data verification) and 6 stations (upper-air verification) located in the Alps and vicinity.

  12. Realistic three-dimensional radiative transfer simulations of observed precipitation

    NASA Astrophysics Data System (ADS)

    Adams, I. S.; Bettenhausen, M. H.

    2013-12-01

    Remote sensing observations of precipitation typically utilize a number of instruments on various platforms. Ground validation campaigns incorporate ground-based and airborne measurements to characterize and study precipitating clouds, while the precipitation measurement constellation envisioned by the Global Precipitation Measurement (GPM) mission includes measurements from differing space-borne instruments. In addition to disparities such as frequency channel selection and bandwidth, measurement geometry and resolution differences between observing platforms result in inherent inconsistencies between data products. In order to harmonize measurements from multiple passive radiometers, a framework is required that addresses these differences. To accomplish this, we have implemented a flexible three-dimensional radiative transfer model. As its core, the radiative transfer model uses the Atmospheric Radiative Transfer Simulator (ARTS) version 2 to solve the radiative transfer equation in three dimensions using Monte Carlo integration. Gaseous absorption is computed with MonoRTM and formatted into look-up tables for rapid processing. Likewise, scattering properties are pre-computed using a number of publicly available codes, such as T-Matrix and DDSCAT. If necessary, a melting layer model can be applied to the input profiles. Gaussian antenna beams estimate the spatial resolutions of the passive measurements, and realistic bandpass characteristics can be included to properly account for the spectral response of the simulated instrument. This work presents three-dimensional simulations of WindSat brightness temperatures for an oceanic rain event sampled by the Tropical Rainfall Measuring Mission (TRMM) satellite. The 2B-31 combined Precipitation Radar / TRMM Microwave Imager (TMI) retrievals provide profiles that are the input to the radiative transfer model. TMI brightness temperatures are also simulated. Comparisons between monochromatic, pencil beam simulations and

  13. How sensitive is Melissa officinalis to realistic ozone concentrations?

    PubMed

    Döring, Anne Sarah; Pellegrini, Elisa; Campanella, Alessandra; Trivellini, Alice; Gennai, Clizia; Petersen, Maike; Nali, Cristina; Lorenzini, Giacomo

    2014-01-01

    Lemon balm (Melissa officinalis, L.; Lamiaceae) was exposed to realistic ozone (O3) dosages (80 ppb for 5 h), because high background levels of O3 are considered to be as harmful as episodic O3 regimes. Temporal alterations of different ecophysiological, biochemical and structural parameters were investigated in order to test if this species can be considered as an O3-bioindicator regarding changes in background concentrations. At the end of ozone exposure, the plants did not exhibit any visible foliar symptoms, as only at microscopic level a small number of dead cells were found. Photosynthetic processes, however, were significantly affected. During and after the treatment, ozone induced a reduction in CO2 fixation capacity (up to 52% after 12 h from the beginning of the treatment) due to mesophyllic limitations. Intercellular CO2 concentration significantly increased in comparison to controls (+90% at the end of the post-fumigation period). Furthermore impairment of carboxylation efficiency (-71% at the end of the post-fumigation period compared to controls in filtered air) and membrane damage in terms of integrity (as demonstrated by a significant rise in solute leakage) were observed. A regulatory adjustment of photosynthetic processes was highlighted during the post-fumigation period by the higher values of qNP and (1-q(P)) and therefore suggests a tendency to reduce the light energy used in photochemistry at the expense of the capacity to dissipate the excess as excitation energy. In addition, the chlorophyll a/b ratio and the de-epoxidation index increased, showing a rearrangement of the pigment composition of the photosynthetic apparatus and a marked activation of photoprotective mechanisms. PMID:24321873

  14. Acoustic simulation in realistic 3D virtual scenes

    NASA Astrophysics Data System (ADS)

    Gozard, Patrick; Le Goff, Alain; Naz, Pierre; Cathala, Thierry; Latger, Jean

    2003-09-01

    The simulation workshop CHORALE developed in collaboration with OKTAL SE company for the French MoD is used by government services and industrial companies for weapon system validation and qualification trials in the infrared domain. The main operational reference for CHORALE is the assessment of the infrared guidance system of the Storm Shadow missile French version, called Scalp. The use of CHORALE workshop is now extended to the acoustic domain. The main objective is the simulation of the detection of moving vehicles in realistic 3D virtual scenes. This article briefly describes the acoustic model in CHORALE. The 3D scene is described by a set of polygons. Each polygon is characterized by its acoustic resistivity or its complex impedance. Sound sources are associated with moving vehicles and are characterized by their spectra and directivities. A microphone sensor is defined by its position, its frequency band and its sensitivity. The purpose of the acoustic simulation is to calculate the incoming acoustic pressure on microphone sensors. CHORALE is based on a generic ray tracing kernel. This kernel possesses original capabilities: computation time is nearly independent on the scene complexity, especially the number of polygons, databases are enhanced with precise physical data, special mechanisms of antialiasing have been developed that enable to manage very accurate details. The ray tracer takes into account the wave geometrical divergence and the atmospheric transmission. The sound wave refraction is simulated and rays cast in the 3D scene are curved according to air temperature gradient. Finally, sound diffraction by edges (hill, wall,...) is also taken into account.

  15. Inter-Hemispherical Currents for Realistic Model of Ionospheric Conductivity

    NASA Astrophysics Data System (ADS)

    Lyatsky, S.; Khazanov, G. V.

    2013-12-01

    We present results of modeling of the global 3-D ionosphere-magnetosphere current system including in addition to the R1 and R2 field-aligned currents also inter-hemispherical currents. The inter-hemispherical currents flow between Northern and Southern conjugate ionospheres in case of a North-South asymmetry in ionospheric conductivity in two hemispheres. These currents link together the ionospheric currents in two hemispheres, so the currents observed in one hemisphere can provide us with information about currents in the opposite hemisphere, which is especially important when their magnitude can not be obtained from direct observation (e.g., in Antarctica). In this study, we investigate the generation of the inter-hemispherical currents for several distributions of ionospheric conductivity in two hemispheres including a simplified model of ionospheric conductivity, which is important for better understanding of the expected distribution and magnitude of these currents, and a more realistic model of ionospheric conductivity, which is observed during magnetospheric substorms, when the geometry of the inter-hemispherical currents is more complicated. Simulation results show that the inter-hemispherical currents during substorms could play a very significant role, and neglecting these currents does not allow obtaining the correct picture of 3-D magnetosphere-ionosphere current system. These currents are an important part of 3-D field-aligned current system, and they are especially strong during summer-winter months, when they are comparable in magnitude with the R2 currents (about ~0.5 MA). Inter-hemispherical currents map. Left panel is related to Northern hemisphere, right panel to Southern. R1 and R2 currents are not shown; their locations are indicated by the red and blue dashed circles, respectively. The inter-hemispherical currents appear inside the auroral zone in the region of conductivity gradient. The currents in both hemispheres are equal in magnitude and

  16. Secondary eyewall formation in high resolution, realistic hurricane simulations

    NASA Astrophysics Data System (ADS)

    Abarca Fuente, Sergio Federico

    This dissertation explores the dynamics of secondary eyewall formation (SEF) through the analysis of high resolution (1.33 km), realistic integrations of the National Center for Atmospheric Research Advanced Hurricane Weather Research and Forecasting model. Numerical simulations of Hurricanes Katrina and Rita (2005) and Igor (2010) are analyzed. The evolution of these storms was well captured by the model and each simulation exhibited a secondary eyewall (SE): a ring of deep convection separate from the primary eyewall that develops a strong acceleration of the tangential wind. This acceleration manifests itself as an abrupt radial expansion of the tangential wind field, sometimes followed by an independent wind maximum. The convective and wind structures of the SE in the simulations are shown to be consistent with observations. The results presented suggest that unbalanced dynamic processes are fundamental in SEF. It is shown that vortical hot towers (VHTs) are the convective structures that constitute the SE. Their collective effects account for, (a) the establishment of the convective maximum, (b) the weakening of the primary eyewall through competition for inflow (that may culminate with an eyewall replacement cycle) and (c) the wind acceleration, that may or may not express itself as an independent secondary maximum in the tangential wind field. It is shown that the establishment of the VHTs that constitute the SE can be the result of different processes: (1) the release of large amounts of buoyant energy at the radius of the SE; and (2) the accumulation of potential vorticity at the stagnation radius of vortex Rossby waves. In either case, the SE is characterized by a positive potential vorticity anomaly in the lower troposphere that is further enhanced by VHT activity and the axisymmetrization of their remnants, increasing the likelihood for future convection to occur.

  17. The buoyancy-driven ocean circulation with realistic bathymetry

    NASA Astrophysics Data System (ADS)

    Gjermundsen, Ada; LaCasce, Joseph H.; Denstad, Liv

    2015-04-01

    In contrast to the wind-driven ocean circulation, where the concept of a Sverdrup interior and western boundary currents is generally accepted, we lack a simple dynamical framework for rationalizing the buoyancy-driven circulation. Thus most of our intuition is based on numerical solutions, primarily in idealized basins (e.g. Huck et al., 1999; Park and Bryan, 2001). Here we examine numerical solutions of the global circulation with realistic bathymetry, driven solely by surface buoyancy forcing. Explicit wind forcing is excluded, although vertical mixing is retained. The model (the MITgcm) is run with a hybrid resolution scheme, to capture approximately the variation of the deformation radius. The character of the resulting flow is consistent in many ways with the observed ocean circulation. There is inflow to and sinking in the Nordic Seas, baroclinic western boundary currents and an overturning streamfunction which closely resembles those obtained in full GCMs and in observations. Furthermore, the solutions share many features with solutions obtained with a linear analytical model (Pedlosky, 1969; LaCasce, 2004), suggesting the latter may be conceptually useful, despite lacking bathymetry. We discuss these points, as well as implications for the climate system in general. References: Pedlosky, J. (1969). Linear theory of the circulation of a stratified ocean. Journal of Fluid Mechanics, 35, 185-205. Huck, T., A. J. Weaver and A. Colin de Verdière (1999). On the influence of the parameterization of lateral boundary layers on the thermohaline circulation in coarse-resolution ocean models. Journal of Marine Research, 57(3), 387-426. Park, Y. G. and K. Bryan (2001). Comparison of thermally driven circulations from a depth-coordinate model and an isopycnal-layer model. Part II: The difference and structure of the circulations. Journal of Physical Oceanography, 31(9), 2612-2624. LaCasce, J. H. (2004). Diffusivity and viscosity dependence in the linear thermocline

  18. Validation of a dose warping algorithm using clinically realistic scenarios

    PubMed Central

    Dehghani, H; Green, S; Webster, G J

    2015-01-01

    Objective: Dose warping following deformable image registration (DIR) has been proposed for interfractional dose accumulation. Robust evaluation workflows are vital to clinically implement such procedures. This study demonstrates such a workflow and quantifies the accuracy of a commercial DIR algorithm for this purpose under clinically realistic scenarios. Methods: 12 head and neck (H&N) patient data sets were used for this retrospective study. For each case, four clinically relevant anatomical changes have been manually generated. Dose distributions were then calculated on each artificially deformed image and warped back to the original anatomy following DIR by a commercial algorithm. Spatial registration was evaluated by quantitative comparison of the original and warped structure sets, using conformity index and mean distance to conformity (MDC) metrics. Dosimetric evaluation was performed by quantitative comparison of the dose–volume histograms generated for the calculated and warped dose distributions, which should be identical for the ideal “perfect” registration of mass-conserving deformations. Results: Spatial registration of the artificially deformed image back to the planning CT was accurate (MDC range of 1–2 voxels or 1.2–2.4 mm). Dosimetric discrepancies introduced by the DIR were low (0.02 ± 0.03 Gy per fraction in clinically relevant dose metrics) with no statistically significant difference found (Wilcoxon test, 0.6 ≥ p ≥ 0.2). Conclusion: The reliability of CT-to-CT DIR-based dose warping and image registration was demonstrated for a commercial algorithm with H&N patient data. Advances in knowledge: This study demonstrates a workflow for validation of dose warping following DIR that could assist physicists and physicians in quantifying the uncertainties associated with dose accumulation in clinical scenarios. PMID:25791569

  19. Vaccine delivery using nanoparticles

    PubMed Central

    Gregory, Anthony E.; Titball, Richard; Williamson, Diane

    2013-01-01

    Vaccination has had a major impact on the control of infectious diseases. However, there are still many infectious diseases for which the development of an effective vaccine has been elusive. In many cases the failure to devise vaccines is a consequence of the inability of vaccine candidates to evoke appropriate immune responses. This is especially true where cellular immunity is required for protective immunity and this problem is compounded by the move toward devising sub-unit vaccines. Over the past decade nanoscale size (<1000 nm) materials such as virus-like particles, liposomes, ISCOMs, polymeric, and non-degradable nanospheres have received attention as potential delivery vehicles for vaccine antigens which can both stabilize vaccine antigens and act as adjuvants. Importantly, some of these nanoparticles (NPs) are able to enter antigen-presenting cells by different pathways, thereby modulating the immune response to the antigen. This may be critical for the induction of protective Th1-type immune responses to intracellular pathogens. Their properties also make them suitable for the delivery of antigens at mucosal surfaces and for intradermal administration. In this review we compare the utilities of different NP systems for the delivery of sub-unit vaccines and evaluate the potential of these delivery systems for the development of new vaccines against a range of pathogens. PMID:23532930

  20. Technological Delivery Systems.

    ERIC Educational Resources Information Center

    Kennedy, Don; And Others

    A section on technological delivery systems, presented as part of the second Australian National Workshop on Distance Education (Perth, 1983), contains four papers on using technological resources to provide educational services to persons in isolated locations. The first paper, by Don Kennedy, covers the use of satellite broadcasting of course…

  1. Fluid delivery control system

    SciTech Connect

    Hoff, Brian D.; Johnson, Kris William; Algrain, Marcelo C.; Akasam, Sivaprasad

    2006-06-06

    A method of controlling the delivery of fluid to an engine includes receiving a fuel flow rate signal. An electric pump is arranged to deliver fluid to the engine. The speed of the electric pump is controlled based on the fuel flow rate signal.

  2. Document Delivery Update.

    ERIC Educational Resources Information Center

    Nelson, Nancy Melin

    1992-01-01

    Presents highlights of research that used industrywide surveys, focus groups, personal interviews, and industry-published data to explore the future of electronic information delivery in libraries. Topics discussed include CD-ROMs; prices; full-text products; magnetic tape leasing; engineering and technical literature; connections between online…

  3. Transdimensional Bayesian Joint Inversion of Complementary Seismic Observables with Realistic Data Uncertainties

    NASA Astrophysics Data System (ADS)

    Gao, C.; Lekic, V.

    2014-12-01

    Due to their different and complementary sensitivities to structure, multiple seismic observables are often combined to image the Earth's deep interior. We use a reversible jump Markov chain Monte Carlo (rjMCMC) algorithm to incorporate surface wave dispersion, particle motion ellipticity (HZ ratio), and receiver functions into transdimensional, Bayesian inversion for the profiles of shear velocity (Vs), compressional velocity (Vp), and density beneath a seismic station. While traditional inversion approaches seek a single best-fit model, a Bayesian approach yields an ensemble of models, allowing us to fully quantify uncertainty and trade-offs between model parameters. Furthermore, we show that by treating the number model parameters as an unknown to be estimated from the data, we both eliminate the need for a fixed parameterization based on prior information, and obtain better model estimates with reduced trade-offs. Optimal weighting of disparate datasets is paramount for maximizing the resolving power of joint inversions. In a Bayesian framework, data uncertainty directly determines the variance of the model posterior probability distribution; therefore, characteristics of the uncertainties on the observables become even more important in the inversion (Bodin et al., 2011). To properly account for the noise characteristics of the different seismic observables, we compute covariance matrices of data errors for each data type by generating realistic synthetic noise using noise covariance matrices computed from thousands of noise samples, and then measuring the seismic observables of interest from synthetic waveforms contaminated by many different realizations of noise. We find large non-diagonal terms in the covariance matrices for different data types, indicating that typical assumptions of uncorrelated data errors are unjustified. We quantify how the use of realistic data covariance matrices in the joint inversion affects the retrieval of seismic structure under

  4. Monte Carlo simulated coronary angiograms of realistic anatomy and pathology models

    NASA Astrophysics Data System (ADS)

    Kyprianou, Iacovos S.; Badal, Andreu; Badano, Aldo; Banh, Diemphuc; Freed, Melanie; Myers, Kyle J.; Thompson, Laura

    2007-03-01

    We have constructed a fourth generation anthropomorphic phantom which, in addition to the realistic description of the human anatomy, includes a coronary artery disease model. A watertight version of the NURBS-based Cardiac-Torso (NCAT) phantom was generated by converting the individual NURBS surfaces of each organ into closed, manifold and non-self-intersecting tessellated surfaces. The resulting 330 surfaces of the phantom organs and tissues are now comprised of ~5×10 6 triangles whose size depends on the individual organ surface normals. A database of the elemental composition of each organ was generated, and material properties such as density and scattering cross-sections were defined using PENELOPE. A 300 μm resolution model of a heart with 55 coronary vessel segments was constructed by fitting smooth triangular meshes to a high resolution cardiac CT scan we have segmented, and was consequently registered inside the torso model. A coronary artery disease model that uses hemodynamic properties such as blood viscosity and resistivity was used to randomly place plaque within the artery tree. To generate x-ray images of the aforementioned phantom, our group has developed an efficient Monte Carlo radiation transport code based on the subroutine package PENELOPE, which employs an octree spatial data-structure that stores and traverses the phantom triangles. X-ray angiography images were generated under realistic imaging conditions (90 kVp, 10° Wanode spectra with 3 mm Al filtration, ~5×10 11 x-ray source photons, and 10% per volume iodine contrast in the coronaries). The images will be used in an optimization algorithm to select the optimal technique parameters for a variety of imaging tasks.

  5. Nanotopography applications in drug delivery.

    PubMed

    Walsh, Laura A; Allen, Jessica L; Desai, Tejal A

    2015-01-01

    Refinement of micro- and nanofabrication in the semiconductor field has led to innovations in biomedical technologies. Nanotopography, in particular, shows great potential in facilitating drug delivery. The flexibility of fabrication techniques has created a diverse array of topographies that have been developed for drug delivery applications. Nanowires and nanostraws deliver drug cytosolically for in vitro and ex vivo applications. In vivo drug delivery is limited by the barrier function of the epithelium. Nanowires on microspheres increase adhesion and residence time for oral drug delivery, while also increasing permeability of the epithelium. Low aspect ratio nanocolumns increase paracellular permeability, and in conjunction with microneedles increase transdermal drug delivery of biologics in vivo. In summary, nanotopography is a versatile tool for drug delivery. It can deliver directly to cells or be used for in vivo delivery across epithelial barriers. This editorial highlights the application of nanotopography in the field of drug delivery. PMID:26512871

  6. Righteous realists: Perceptions of American power and responsibility in the nuclear age

    SciTech Connect

    Rosenthal, J.H.

    1988-01-01

    This is a study of the moral and ethical dimensions of political realism in post-World War II America, especially in relation to realist thought on nuclear weapons issues. Emphasis is placed on evolving notions of power and responsibility as they form the basis for a realist philosophy of power in the nuclear age. It is argued that the realists developed a concept of responsible power which was a hybrid of traditional American ideals and European Realpolitik. Included are chapters on the personal and intellectual background of five noteworthy realists, the realist position on some basic dilemmas in political ethics, the problem of usable and unusable force, the realists' view on deterrence and arms control, the question of democracy versus guardianship, and the realists as cultural critics. This study highlights the coherence of realist thought while pointing out the paradoxes upon which it is based. It situates realism in its historical context and reveals realism's relationship to explicit political and cultural values. It concludes that at their core, the realists were moralists; and realism was the entity through which they reconciled morality and power.

  7. Robotic Delivery of Complex Radiation Volumes for Small Animal Research

    PubMed Central

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

    2011-01-01

    The Small Animal Radiation Research Platform (SARRP) is a novel and complete system capable of delivering multidirectional (focal), kilo-voltage radiation fields to targets in small animals under robotic control using cone-beam CT (CBCT) image guidance. The capability of the SARRP to deliver highly focused beams to multiple animal models provides new research opportunities that more realistically bridge laboratory research and clinical translation. This paper describes the design and operation of the SARRP for precise radiation delivery. Different delivery procedures are presented which enable the system to radiate through a series of points, representative of a complex shape. A particularly interesting case is shell dose irradiation, where the goal is to deliver a high dose of radiation to the shape surface, with minimal dose to the shape interior. The ability to deliver a dose shell allows mechanistic research of how a tumor interacts with its microenvironment to sustain its growth and lead to its resistance or recurrence. PMID:21643448

  8. PECTIN IN CONTROLLED DRUG DELIVERY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Controlled drug delivery remains a research focus for public health to enhance patient compliance, drug efficiency and to reduce the side effects of drugs. Pectin, an edible plant polysaccharide, has shown potential for the construction of drug delivery systems for site-specific drug delivery. Sev...

  9. Continuing Professional Education Delivery Systems.

    ERIC Educational Resources Information Center

    Weeks, James P.

    This investigation of delivery systems for continuing professional education provides an overview of current operational delivery systems in continuing professional education, drawing on experience as found in the literature. Learning theories and conclusions are woven into the descriptive text. Delivery systems profiled in the paper include the…

  10. Realistic models of pion-exchange three-nucleon interactions

    SciTech Connect

    Pieper, Steven C.; Pandharipande, V. R.; Wiringa, R. B.; Carlson, J.

    2001-07-01

    We present realistic models of pion-exchange three-nucleon interactions obtained by fitting the energies of all the 17 bound or narrow states of 3{<=}A{<=}8 nucleons, calculated with less than 2% error using the Green's function Monte Carlo method. The models contain two-pion-exchange terms due to {pi}N scattering in S and P waves, three-pion-exchange terms due to ring diagrams with one {Delta} in the intermediate states, and a phenomenological repulsive term to take into account relativistic effects, the suppression of the two-pion-exchange two-nucleon interaction by the third nucleon, and other effects. The models have five parameters, consisting of the strength of the four interactions and the short-range cutoff. The 17 fitted energies are insufficient to determine all of them uniquely. We consider five models, each having three adjustable parameters and assumed values for the other two. They reproduce the observed energies with an rms error <1% when used together with the Argonne v{sub 18} two-nucleon interaction. In one of the models the {pi}N S-wave scattering interaction is set to zero; in all others it is assumed to have the strength suggested by chiral effective-field theory. One of the models also assumes that the {pi}N P-wave scattering interaction has the strength suggested by effective-field theories, and the cutoff is adjusted to fit the data. In all other models the cutoff is taken to be the same as in the v{sub 18} interaction. The effect of relativistic boost correction to the two-nucleon interaction on the strength of the repulsive three-nucleon interaction is estimated. Many calculated properties of A{<=}8 nuclei, including radii, magnetic dipole, and electric quadrupole moments, isobaric analog energy differences, etc., are tabulated. Results obtained with only Argonne v{sub 8}' and v{sub 18} interactions are also reported. In addition, we present results for seven- and eight-body neutron drops in external potential wells.

  11. Interpreting Observations of Galaxies through Simulations with Realistic ISM Physics

    NASA Astrophysics Data System (ADS)

    Jonsson, Patrik

    interstellar medium on scales of tens of parsecs using realistic physics. These simulations will then be processed with our dust radiation- transfer code Sunrise, generating ``simulated observations'' in the form of images, spectra, and integral field unit-style data cubes including kinematics, directly testing whether the included physical processes are consistent with observed samples of galaxies. The proposed research is well aligned with the goals of the NASA astrophysics theory program, as it is fundamentally oriented towards facilitating the interpretation of observations from NASA facilities such as the Hubble, Galex, Spitzer, and the upcoming James Webb Space Telescope, as well as other ground- and space-based facilities.

  12. Peptide and protein delivery using new drug delivery systems.

    PubMed

    Jain, Ashish; Jain, Aviral; Gulbake, Arvind; Shilpi, Satish; Hurkat, Pooja; Jain, Sanjay K

    2013-01-01

    Pharmaceutical and biotechnological research sorts protein drug delivery systems by importance based on their various therapeutic applications. The effective and potent action of the proteins/peptides makes them the drugs of choice for the treatment of numerous diseases. Major research issues in protein delivery include the stabilization of proteins in delivery devices and the design of appropriate target-specific protein carriers. Many efforts have been made for effective delivery of proteins/peptidal drugs through various routes of administrations for successful therapeutic effects. Nanoparticles made of biodegradable polymers such as poly lactic acid, polycaprolactone, poly(lactic-co-glycolic acid), the poly(fumaric-co-sebacic) anhydride chitosan, and modified chitosan, as well as solid lipids, have shown great potential in the delivery of proteins/peptidal drugs. Moreover, scientists also have used liposomes, PEGylated liposomes, niosomes, and aquasomes, among others, for peptidal drug delivery. They also have developed hydrogels and transdermal drug delivery systems for peptidal drug delivery. A receptor-mediated delivery system is another attractive strategy to overcome the limitation in drug absorption that enables the transcytosis of the protein across the epithelial barrier. Modification such as PEGnology is applied to various proteins and peptides of the desired protein and peptides also increases the circulating life, solubility and stability, pharmacokinetic properties, and antigenicity of protein. This review focuses on various approaches for effective protein/peptidal drug delivery, with special emphasis on insulin delivery. PMID:23662604

  13. Vaginal Birth After Cesarean Delivery: Deciding on a Trial of Labor After a Cesarean Delivery (TOLAC)

    MedlinePlus

    ... a previous pregnancy, TOLAC is not advised. • A pregnancy problem or a medical condition that makes vaginal delivery risky • Type of hospital—The hospital in which you have a TOLAC should be prepared to deal with emergencies that may arise. Whatever I decide, are there ...

  14. Realistic opto-mechanical simulation and tolerancing of an automotive optical transmitter coupling system

    NASA Astrophysics Data System (ADS)

    Vervaeke, Michael; Moens, Els; Meuret, Youri; Ottevaere, Heidi; Van Buggenhout, Carl; De Pauw, Piet; Thienpont, Hugo

    2010-05-01

    The advent of Plastic Optical Fibre (POF) opened perspectives for numerous applications in the field of datacommunications. POF is increasingly popular in the automotive industry as a robust, lightweight, electromagnetic interference free, easy and cheap to install alternative to electrical wiring for high-speed entertainment, navigation and data acquisition systems in cars. The main challenge for the introduction of datacommunication systems based on POF is imposed by the working conditions of automotive applications: systems should remain fully functional in a temperature range from -40 °C to +115 °C . Furthermore, standardisation and mechanical design considerations put a number of other boundary conditions. We designed a misalignment-tolerant optical coupling system according to the Media Oriented Systems Transport standard (MOST) to convey the divergent beam from a Resonant Cavity Light Emitting Diode (RCLED) into a Step-Index (SI) multimode POF mounted in a detachable ferrule. In this contribution we describe the methodology to synthesize the dimensions and tolerances on the optical components in the coupling system. A Monte Carlo optimisation algorithm on the full three-dimensional (3D) description of the complete RCLED package and detachable POF ferrule was used to allow a realistic modelling of all misalignments that could occur in the production chain. We select the best suited system according to manufacturing and assembly capabilities as well as its suitability for automotive applications.

  15. Polarization-resolved simulations of multiple-order rainbows using realistic raindrop shapes

    NASA Astrophysics Data System (ADS)

    Haußmann, Alexander

    2016-05-01

    This paper presents selected results of a simulation study of the first five (primary-quinary) rainbow orders based on a realistic, size-dependent shape model for falling raindrops, taking into account that the drops' bottom part is flattened to higher degree than the dome-like top part. Moreover, broad drop size distributions are included in the simulations, as it is one goal of this paper to analyze, whether the predicted amplification and attenuation patterns for higher-order rainbows, as derived from previous simulations with monodisperse drop sizes, will still be pronounced under the conditions of natural rainfall. Secondly, deviations of the multiple rainbow orders' polarization state from the reference case of spherical drops are discussed. It is shown that each rainbow order may contain a small amount of circularly polarized light due to total internal reflections. Thirdly, it is investigated, how the conditions that generate twinned primary rainbows will affect the higher orders. For the simulations, geometric-optic ray tracing of the full Stokes vector as well as an approximate approach using appropriately shifted Debye series data is applied.

  16. Analysis of Market Opportunities for Chinese Private Express Delivery Industry

    NASA Astrophysics Data System (ADS)

    Jiang, Changbing; Bai, Lijun; Tong, Xiaoqing

    China's express delivery market has become the arena in which each express enterprise struggles to chase due to the huge potential demand and high profitable prospects. So certain qualitative and quantitative forecast for the future changes of China's express delivery market will help enterprises understand various types of market conditions and social changes in demand and adjust business activities to enhance their competitiveness timely. The development of China's express delivery industry is first introduced in this chapter. Then the theoretical basis of the regression model is overviewed. We also predict the demand trends of China's express delivery market by using Pearson correlation analysis and regression analysis from qualitative and quantitative aspects, respectively. Finally, we draw some conclusions and recommendations for China's express delivery industry.

  17. Mucoadhesive drug delivery systems

    PubMed Central

    Shaikh, Rahamatullah; Raj Singh, Thakur Raghu; Garland, Martin James; Woolfson, A David; Donnelly, Ryan F.

    2011-01-01

    Mucoadhesion is commonly defined as the adhesion between two materials, at least one of which is a mucosal surface. Over the past few decades, mucosal drug delivery has received a great deal of attention. Mucoadhesive dosage forms may be designed to enable prolonged retention at the site of application, providing a controlled rate of drug release for improved therapeutic outcome. Application of dosage forms to mucosal surfaces may be of benefit to drug molecules not amenable to the oral route, such as those that undergo acid degradation or extensive first-pass metabolism. The mucoadhesive ability of a dosage form is dependent upon a variety of factors, including the nature of the mucosal tissue and the physicochemical properties of the polymeric formulation. This review article aims to provide an overview of the various aspects of mucoadhesion, mucoadhesive materials, factors affecting mucoadhesion, evaluating methods, and finally various mucoadhesive drug delivery systems (buccal, nasal, ocular, gastro, vaginal, and rectal). PMID:21430958

  18. Delivery strategies for antiparasitics.

    PubMed

    Kayser, Oliver; Kiderlen, Albrecht F

    2003-02-01

    Optimisation of drug carrier systems and drug delivery strategies that take into account the peculiarities of individual infectious agents and diseases are key elements of modern drug development. In the following, different aspects of a rational design for antiparasitic drug formulation will be reviewed, covering delivery systems such as nano- and microparticles, liposomes, emulsions and microemulsions, cochleates and bioadhesive macromolecules. Functional properties for each carrier system will be discussed as well as their therapeutic efficacy for parasitic diseases, including leishmaniasis, human African trypanosomiasis, human cryptosporidiosis, malaria and schistosomiasis. Critical issues for the application of drug carrier systems will be discussed, focusing on biopharmaceutical and pathophysiological parameters such as routes of application, improvement of body distribution and targeting intracellularly persisting pathogens. PMID:12556214

  19. Compact SPS - Power delivery

    NASA Astrophysics Data System (ADS)

    Pospisil, M.; Pospisilova, L.

    1982-09-01

    The power deliverable by a compact solar Space Power Station (SPS) is a function of its outer surface shape. Methods of fitting the power delivery curve of such a system to different patterns of daily power demand are considered that involve the appropriate choice of the number of satellites, their maximal power, height to width ratio and the shift of longitude with respect to the receiving station. Changes in the daily delivery curve can be made by altering the longitudes and orientations of the satellites. Certain limitations to the choice of parameters exist, such as: the height to width ratio should be near 1.2, and the sum of longitude and orientation changes will probably not be greater than 50 deg. The optimization of the peak to average power ratio is also discussed.

  20. Terplex Gene Delivery System.

    PubMed

    Kim, Sung Wan

    2005-01-01

    Polymeric gene delivery systems have been developed to overcome problems caused by viral carriers. They are low cytotoxic, have no size limit, are convenient in handling, of low cost and reproducible. A Terplex gene delivery system consisting of plasmid DNA, low density lipoprotein and hydropholized poly-L-lysine was designed and characterized. The plasmid DNA, when formulated with stearyl PLL and LDL, forms a stable and hydrophobicity/charge-balanced Terplex system of optimal size for efficient cellular uptake. DNA is still intact after the Terplex formation. This information is expected to be utilized for the development of improved transfection vector for in vivo gene therapy. Terplex DNA complex showed significantly longer retention in the vascular space than naked DNA. This system was used in the augmentation of myocardial transfection at an infarction site with the VEGF gene. PMID:16243067

  1. Terplex gene delivery system.

    PubMed

    Kim, Sung Wan

    2005-01-01

    Polymeric gene delivery systems have been developed to overcome problems caused by viral carriers. They are low cytotoxic, have no size limit, are convenient in handling, of low cost and reproducible. A Terplex gene delivery system consisting of plasmid DNA, low density lipoprotein and hydropholized poly-L-lysine was designed and characterized. The plasmid DNA, when formulated with stearyl PLL and LDL, forms a stable and hydrophobicity/charge-balanced Terplex system of optimal size for efficient cellular uptake. DNA is still intact after the Terplex formation. This information is expected to be utilized for the development of improved transfection vector for in vivo gene therapy. Terplex DNA complex showed significantly longer retention in the vascular space than naked DNA. This system was used in the augmentation of myocardial transfection at an infarction site with the VEGF gene. PMID:16240997

  2. Reproductive health care delivery.

    PubMed

    Lindgren, Mark C; Ross, Lawrence S

    2014-02-01

    Most patients in the United States with reproductive health disorders are not covered by their health insurance for these problems. Health insurance plans consider reproductive care as a lifestyle choice not as a disease. If coverage is provided it is, most often, directed to female factor infertility and advanced reproductive techniques, ignoring male factor reproductive disorders. This article reviews the history of reproductive health care delivery and its present state, and considers its possible future direction. PMID:24286778

  3. Mucosal delivery of vaccines.

    PubMed

    Del Giudice, G; Pizza, M; Rappuoli, R

    1999-09-01

    Oral delivery represents one of the most pursued approaches for large-scale human vaccination. Due to the different characteristics of mucosal immune response, as compared with systemic response, oral immunization requires particular methods of antigen preparation and selective strategies of adjuvanticity. In this paper, we describe the preparation and use of genetically detoxified bacterial toxins as mucosal adjuvants and envisage the possibility of their future exploitation for human oral vaccines. PMID:10525451

  4. Nanovehicular intracellular delivery systems.

    PubMed

    Prokop, Ales; Davidson, Jeffrey M

    2008-09-01

    This article provides an overview of principles and barriers relevant to intracellular drug and gene transport, accumulation and retention (collectively called as drug delivery) by means of nanovehicles (NV). The aim is to deliver a cargo to a particular intracellular site, if possible, to exert a local action. Some of the principles discussed in this article apply to noncolloidal drugs that are not permeable to the plasma membrane or to the blood-brain barrier. NV are defined as a wide range of nanosized particles leading to colloidal objects which are capable of entering cells and tissues and delivering a cargo intracelullarly. Different localization and targeting means are discussed. Limited discussion on pharmacokinetics and pharmacodynamics is also presented. NVs are contrasted to micro-delivery and current nanotechnologies which are already in commercial use. Newer developments in NV technologies are outlined and future applications are stressed. We also briefly review the existing modeling tools and approaches to quantitatively describe the behavior of targeted NV within the vascular and tumor compartments, an area of particular importance. While we list "elementary" phenomena related to different level of complexity of delivery to cancer, we also stress importance of multi-scale modeling and bottom-up systems biology approach. PMID:18200527

  5. Nanovehicular Intracellular Delivery Systems

    PubMed Central

    PROKOP, ALES; DAVIDSON, JEFFREY M.

    2013-01-01

    This article provides an overview of principles and barriers relevant to intracellular drug and gene transport, accumulation and retention (collectively called as drug delivery) by means of nanovehicles (NV). The aim is to deliver a cargo to a particular intracellular site, if possible, to exert a local action. Some of the principles discussed in this article apply to noncolloidal drugs that are not permeable to the plasma membrane or to the blood–brain barrier. NV are defined as a wide range of nanosized particles leading to colloidal objects which are capable of entering cells and tissues and delivering a cargo intracelullarly. Different localization and targeting means are discussed. Limited discussion on pharmacokinetics and pharmacodynamics is also presented. NVs are contrasted to micro-delivery and current nanotechnologies which are already in commercial use. Newer developments in NV technologies are outlined and future applications are stressed. We also briefly review the existing modeling tools and approaches to quantitatively describe the behavior of targeted NV within the vascular and tumor compartments, an area of particular importance. While we list “elementary” phenomena related to different level of complexity of delivery to cancer, we also stress importance of multi-scale modeling and bottom-up systems biology approach. PMID:18200527

  6. Single compartment drug delivery

    PubMed Central

    Cima, Michael J.; Lee, Heejin; Daniel, Karen; Tanenbaum, Laura M.; Mantzavinou, Aikaterini; Spencer, Kevin C.; Ong, Qunya; Sy, Jay C.; Santini, John; Schoellhammer, Carl M.; Blankschtein, Daniel; Langer, Robert S.

    2014-01-01

    Drug design is built on the concept that key molecular targets of disease are isolated in the diseased tissue. Systemic drug administration would be sufficient for targeting in such a case. It is, however, common for enzymes or receptors that are integral to disease to be structurally similar or identical to those that play important biological roles in normal tissues of the body. Additionally, systemic administration may not lead to local drug concentrations high enough to yield disease modification because of rapid systemic metabolism or lack of sufficient partitioning into the diseased tissue compartment. This review focuses on drug delivery methods that physically target drugs to individual compartments of the body. Compartments such as the bladder, peritoneum, brain, eye and skin are often sites of disease and can sometimes be viewed as “privileged,” since they intrinsically hinder partitioning of systemically administered agents. These compartments have become the focus of a wide array of procedures and devices for direct administration of drugs. We discuss the rationale behind single compartment drug delivery for each of these compartments, and give an overview of examples at different development stages, from the lab bench to phase III clinical trials to clinical practice. We approach single compartment drug delivery from both a translational and a technological perspective. PMID:24798478

  7. Novel antigen delivery systems.

    PubMed

    Trovato, Maria; De Berardinis, Piergiuseppe

    2015-08-12

    Vaccines represent the most relevant contribution of immunology to human health. However, despite the remarkable success achieved in the past years, many vaccines are still missing in order to fight important human pathologies and to prevent emerging and re-emerging diseases. For these pathogens the known strategies for making vaccines have been unsuccessful and thus, new avenues should be investigated to overcome the failure of clinical trials and other important issues including safety concerns related to live vaccines or viral vectors, the weak immunogenicity of subunit vaccines and side effects associated with the use of adjuvants. A major hurdle of developing successful and effective vaccines is to design antigen delivery systems in such a way that optimizes antigen presentation and induces broad protective immune responses. Recent advances in vector delivery technologies, immunology, vaccinology and system biology, have led to a deeper understanding of the molecular and cellular mechanisms by which vaccines should stimulate both arms of the adaptive immune responses, offering new strategies of vaccinations. This review is an update of current strategies with respect to live attenuated and inactivated vaccines, DNA vaccines, viral vectors, lipid-based carrier systems such as liposomes and virosomes as well as polymeric nanoparticle vaccines and virus-like particles. In addition, this article will describe our work on a versatile and immunogenic delivery system which we have studied in the past decade and which is derived from a non-pathogenic prokaryotic organism: the "E2 scaffold" of the pyruvate dehydrogenase complex from Geobacillus stearothermophilus. PMID:26279977

  8. Transmembrane heme delivery systems

    PubMed Central

    Goldman, Barry S.; Beck, David L.; Monika, Elizabeth M.; Kranz, Robert G.

    1998-01-01

    Heme proteins play pivotal roles in a wealth of biological processes. Despite this, the molecular mechanisms by which heme traverses bilayer membranes for use in biosynthetic reactions are unknown. The biosynthesis of c-type cytochromes requires that heme is transported to the bacterial periplasm or mitochondrial intermembrane space where it is covalently ligated to two reduced cysteinyl residues of the apocytochrome. Results herein suggest that a family of integral membrane proteins in prokaryotes, protozoans, and plants act as transmembrane heme delivery systems for the biogenesis of c-type cytochromes. The complete topology of a representative from each of the three subfamilies was experimentally determined. Key histidinyl residues and a conserved tryptophan-rich region (designated the WWD domain) are positioned at the site of cytochrome c assembly for all three subfamilies. These histidinyl residues were shown to be essential for function in one of the subfamilies, an ABC transporter encoded by helABCD. We believe that a directed heme delivery pathway is vital for the synthesis of cytochromes c, whereby heme iron is protected from oxidation via ligation to histidinyl residues within the delivery proteins. PMID:9560218

  9. A Realistic Hot Water Draw Specification for Rating Solar Water Heaters

    SciTech Connect

    Burch, J.

    2012-06-01

    In the United States, annual performance ratings for solar water heaters are simulated, using TMY weather and specified water draw. This paper proposes a more realistic ratings draw that eliminates most bias by improving mains inlet temperature and by specifying realistic hot water use. Presented at the 2012 World Renewable Energy Forum; Denver, Colorado; May 13-17, 2012.

  10. The Effects of Instruction on Elementary Teacher's Realistic and Idealistic Attitudes Toward Selected Science Related Concepts.

    ERIC Educational Resources Information Center

    Bogut, Thomas L.; McFarland, Bruce L.

    Reported is a study designed to determine (1) if there was any significant relationship between elementary teachers' realistic and idealistic attitudes toward selected science-related concepts, (2) if the degree of open- or closed-mindedness of the teachers had any relationship to these realistic or idealistic attitudes, and (3) if instruction had…

  11. Time for realistic job previews in nursing as a recruitment and retention tool.

    PubMed

    Gilmartin, Mattia J; Aponte, Priscilla C; Nokes, Kathleen

    2013-01-01

    Realistic job previews are well-established, cost-effective, and evidence-based recruitment and retention tools that nurses in professional development have largely overlooked. A realistic job preview for experienced staff nurses pioneering the Clinical Nurse Leader® role is presented along with implications for nursing professional development practice. PMID:24060656

  12. Marine Corps Recruit Training Attrition: The Effect of Realistic Job Preview and Stress-Coping Films.

    ERIC Educational Resources Information Center

    Githens, William H.; Zalinski, James

    Two films were evaluated to determine their effectiveness in reducing attrition among Marine Corps recruits. The films were a realistic job preview of military training and a stress-coping film. Platoons of Marine recruits were randomly assigned to four treatment groups: viewing the realistic job preview film, viewing the stress-coping film,…

  13. Magnetohydrodynamic Simulation of a Streamer Beside a Realistic Coronal Hole

    NASA Technical Reports Server (NTRS)

    Suess, S. T.; Wu, S. T.; Wang, A. H.; Poletto, G.

    1994-01-01

    Existing models of coronal streamers establish their credibility and act as the initial state for transients. The models have produced satisfactory streamer simulations, but unsatisfactory coronal hole simulations. This is a consequence of the character of the models and the boundary conditions. The models all have higher densities in the magnetically open regions than occur in coronal holes (Noci, et al., 1993).

  14. Pregnancy and Vaginal Delivery after Sacrohysteropexy

    PubMed Central

    Balsak, Deniz; Eser, Ahmet; Erol, Onur; Deniz Altıntaş, Derya; Aksin, Şerif

    2015-01-01

    Pregnancy and birth after a Pelvic Organ Prolapse (POP) surgery is a rare condition and less is known about the method for delivery. A 31-year-old women with gravida 3 para 3 underwent abdominal sacrohysteropexy and transobturatuar tape (TOT) procedures for stage III prolapse who delivered via vaginal birth and showed no relapse. Sacrohysteropexy is a good option for women with POP who desire fertility with a long term follow-up period. PMID:26199773

  15. Local delivery of nitric oxide: targeted delivery of therapeutics to bone and connective tissues

    PubMed Central

    Nichols, Scott P.; Storm, Wesley L.; Koh, Ahyeon; Schoenfisch, Mark H.

    2012-01-01

    Non-invasive treatment of injuries and disorders affecting bones and connective tissue is a significant challenge facing the medical community. A treatment route that has recently been proposed is nitric oxide (NO) therapy. Nitric oxide plays several roles in physiology with many conditions lacking adequate levels of NO. As NO is a radical, localized delivery via NO donors is essential to promoting biological activity. Herein, we review current literature related to therapeutic NO delivery in the treatment of bone, skin and tendon repair. PMID:22433782

  16. Intracellular Delivery of Proteins via Fusion Peptides in Intact Plants

    PubMed Central

    Ng, Kiaw Kiaw; Motoda, Yoko; Watanabe, Satoru; Sofiman Othman, Ahmad; Kigawa, Takanori; Kodama, Yutaka; Numata, Keiji

    2016-01-01

    In current plant biotechnology, the introduction of exogenous DNA encoding desired traits is the most common approach used to modify plants. However, general plant transformation methods can cause random integration of exogenous DNA into the plant genome. To avoid these events, alternative methods, such as a direct protein delivery system, are needed to modify the plant. Although there have been reports of the delivery of proteins into cultured plant cells, there are currently no methods for the direct delivery of proteins into intact plants, owing to their hierarchical structures. Here, we demonstrate the efficient fusion-peptide-based delivery of proteins into intact Arabidopsis thaliana. Bovine serum albumin (BSA, 66 kDa) was selected as a model protein to optimize conditions for delivery into the cytosol. The general applicability of our method to large protein cargo was also demonstrated by the delivery of alcohol dehydrogenase (ADH, 150 kDa) into the cytosol. The compatibility of the fusion peptide system with the delivery of proteins to specific cellular organelles was also demonstrated using the fluorescent protein Citrine (27 kDa) conjugated to either a nuclear localization signal (NLS) or a peroxisomal targeting signal (PTS). In conclusion, our designed fusion peptide system can deliver proteins with a wide range of molecular weights (27 to 150 kDa) into the cells of intact A. thaliana without interfering with the organelle-targeting peptide conjugated to the protein. We expect that this efficient protein delivery system will be a powerful tool in plant biotechnology. PMID:27100681

  17. Caesarean Delivery Rate Review: An Evidence-Based Analysis

    PubMed Central

    Degani, N; Sikich, N

    2015-01-01

    included data from women with obstetrical conditions that warranted a caesarean delivery. Conclusions There is moderate-quality evidence that—compared with expectant management—an induction policy is associated with a decrease in caesarean delivery rates in low-risk women. There is significant caesarean delivery rate variation among Ontario hospitals. PMID:26366243

  18. Realistic soft tissue deformation strategies for real time surgery simulation.

    PubMed

    Shen, Yunhe; Zhou, Xiangmin; Zhang, Nan; Tamma, Kumar; Sweet, Robert

    2008-01-01

    A volume-preserving deformation method (VPDM) is developed in complement with the mass-spring method (MSM) to improve the deformation quality of the MSM to model soft tissue in surgical simulation. This method can also be implemented as a stand-alone model. The proposed VPDM satisfies the Newton's laws of motion by obtaining the resultant vectors form an equilibrium condition. The proposed method has been tested in virtual surgery systems with haptic rendering demands. PMID:18391343

  19. The characteristics of spontaneously forming physically cross-linked hydrogels composed of two water-soluble phospholipid polymers for oral drug delivery carrier I: hydrogel dissolution and insulin release under neutral pH condition.

    PubMed

    Nam, Kwangwoo; Watanabe, Junji; Ishihara, Kazuhiko

    2004-11-01

    Hydrogels bearing a phospholipid polar group, 2-methacryloyloxyethyl phosphorylcholine (MPC), were prepared from two aqueous solutions of polymers, water-soluble poly[MPC-co-methacrylic acid (MA)] (PMA) and poly[MPC-co-n-butyl methacrylate (BMA)] (PMB). The hydrogel, which was formed by physical cross-linking spontaneously without any chemical reactions and/or any physical stimuli, showed a controllable insulin release through a pH change in the medium by changing the hydrogen bonds. In this study, the mechanical strength, erosion of the hydrogel caused by polymer dissociation, and the release of insulin were examined with attention to the following three parameters of the MPC polymer: molecular weight of the polymers, composition of PMA and PMB (PMA/PMB ratio), and polymer concentration inside the hydrogel. The hydrogel with the highest mechanical strength was obtained at a PMA/PMB ratio = 3/7 (v/v, by volume ratio) while the hydrogel with the slowest dissolution was obtained at a ratio of 5/5 (v/v). The release was in good match with the dissolution and followed anomalous transport for all, but the diffusion exponent n changed according to the PMA/PMB ratio. An increase in the polymer concentration inside the hydrogel caused an increase in the mechanical strength of the hydrogel. When the polymer concentration was more than 20 wt.%, the absorption of water under neutral pH condition (pH 6.8) was observed. The release of insulin was suppressed below 10% during the swelling process of the hydrogel under neutral pH condition, while release was accelerated during the erosion process of the hydrogel. The relationship between erosion of the hydrogel and the release of the insulin depended on the erosion process of the hydrogel but differed according to the PMA/PMB ratio. PMID:15489127

  20. How do primary health care teams learn to integrate intimate partner violence (IPV) management? A realist evaluation protocol

    PubMed Central

    2013-01-01

    Background Despite the existence of ample literature dealing, on the one hand, with the integration of innovations within health systems and team learning, and, on the other hand, with different aspects of the detection and management of intimate partner violence (IPV) within healthcare facilities, research that explores how health innovations that go beyond biomedical issues—such as IPV management—get integrated into health systems, and that focuses on healthcare teams’ learning processes is, to the best of our knowledge, very scarce if not absent. This realist evaluation protocol aims to ascertain: why, how, and under what circumstances primary healthcare teams engage (if at all) in a learning process to integrate IPV management in their practices; and why, how, and under what circumstances team learning processes lead to the development of organizational culture and values regarding IPV management, and the delivery of IPV management services. Methods This study will be conducted in Spain using a multiple-case study design. Data will be collected from selected cases (primary healthcare teams) through different methods: individual and group interviews, routinely collected statistical data, documentary review, and observation. Cases will be purposively selected in order to enable testing the initial middle-range theory (MRT). After in-depth exploration of a limited number of cases, additional cases will be chosen for their ability to contribute to refining the emerging MRT to explain how primary healthcare learn to integrate intimate partner violence management. Discussion Evaluations of health sector responses to IPV are scarce, and even fewer focus on why, how, and when the healthcare services integrate IPV management. There is a consensus that healthcare professionals and healthcare teams play a key role in this integration, and that training is important in order to realize changes. However, little is known about team learning of IPV management, both in

  1. Towards realistic Holocene land cover scenarios: integration of archaeological, palynological and geomorphological records and comparison to global land cover scenarios.

    NASA Astrophysics Data System (ADS)

    De Brue, Hanne; Verstraeten, Gert; Broothaerts, Nils; Notebaert, Bastiaan

    2016-04-01

    Accurate and spatially explicit landscape reconstructions for distinct time periods in human history are essential for the quantification of the effect of anthropogenic land cover changes on, e.g., global biogeochemical cycles, ecology, and geomorphic processes, and to improve our understanding of interaction between humans and the environment in general. A long-term perspective covering Mid and Late Holocene land use changes is recommended in this context, as it provides a baseline to evaluate human impact in more recent periods. Previous efforts to assess the evolution and intensity of agricultural land cover in past centuries or millennia have predominantly focused on palynological records. An increasing number of quantitative techniques has been developed during the last two decades to transfer palynological data to land cover estimates. However, these techniques have to deal with equifinality issues and, furthermore, do not sufficiently allow to reconstruct spatial patterns of past land cover. On the other hand, several continental and global databases of historical anthropogenic land cover changes based on estimates of global population and the required agricultural land per capita have been developed in the past decennium. However, at such long temporal and spatial scales, reconstruction of past anthropogenic land cover intensities and spatial patterns necessarily involves many uncertainties and assumptions as well. Here, we present a novel approach that combines archaeological, palynological and geomorphological data for the Dijle catchment in the central Belgium Loess Belt in order to arrive at more realistic Holocene land cover histories. Multiple land cover scenarios (> 60.000) are constructed using probabilistic rules and used as input into a sediment delivery model (WaTEM/SEDEM). Model outcomes are confronted with a detailed geomorphic dataset on Holocene sediment fluxes and with REVEALS based estimates of vegetation cover using palynological data from

  2. Novel antigen delivery systems

    PubMed Central

    Trovato, Maria; Berardinis, Piergiuseppe De

    2015-01-01

    Vaccines represent the most relevant contribution of immunology to human health. However, despite the remarkable success achieved in the past years, many vaccines are still missing in order to fight important human pathologies and to prevent emerging and re-emerging diseases. For these pathogens the known strategies for making vaccines have been unsuccessful and thus, new avenues should be investigated to overcome the failure of clinical trials and other important issues including safety concerns related to live vaccines or viral vectors, the weak immunogenicity of subunit vaccines and side effects associated with the use of adjuvants. A major hurdle of developing successful and effective vaccines is to design antigen delivery systems in such a way that optimizes antigen presentation and induces broad protective immune responses. Recent advances in vector delivery technologies, immunology, vaccinology and system biology, have led to a deeper understanding of the molecular and cellular mechanisms by which vaccines should stimulate both arms of the adaptive immune responses, offering new strategies of vaccinations. This review is an update of current strategies with respect to live attenuated and inactivated vaccines, DNA vaccines, viral vectors, lipid-based carrier systems such as liposomes and virosomes as well as polymeric nanoparticle vaccines and virus-like particles. In addition, this article will describe our work on a versatile and immunogenic delivery system which we have studied in the past decade and which is derived from a non-pathogenic prokaryotic organism: the “E2 scaffold” of the pyruvate dehydrogenase complex from Geobacillus stearothermophilus. PMID:26279977

  3. Anemia and Oxygen Delivery.

    PubMed

    Bliss, Stuart

    2015-09-01

    Clinical assessment of tissue oxygenation is challenging. Anemia reflects a decreased oxygen carrying capacity of the blood and its significance in the perioperative setting relates largely to the associated risk of insufficient oxygen delivery and cellular hypoxia. Until meaningful clinical measures of tissue oxygenation are available in veterinary practice, clinicians must rely on evaluation of a patient's hemodynamic and ventilatory performance, along with biochemical and hemogasometric measurements. Blood transfusion is used commonly for treatment of perioperative anemia, and may improve tissue oxygenation by normalizing the rheologic properties of blood and enhancing perfusion, independent of increases in oxygen carrying capacity. PMID:26033442

  4. DELIVERY OF THERAPEUTIC PROTEINS

    PubMed Central

    Pisal, Dipak S.; Kosloski, Matthew P.; Balu-Iyer, Sathy V.

    2009-01-01

    The safety and efficacy of protein therapeutics are limited by three interrelated pharmaceutical issues, in vitro and in vivo instability, immunogenicity and shorter half-lives. Novel drug modifications for overcoming these issues are under investigation and include covalent attachment of poly(ethylene glycol) (PEG), polysialic acid, or glycolic acid, as well as developing new formulations containing nanoparticulate or colloidal systems (e.g. liposomes, polymeric microspheres, polymeric nanoparticles). Such strategies have the potential to develop as next generation protein therapeutics. This review includes a general discussion on these delivery approaches. PMID:20049941

  5. Realistic ice sputtering experiments for the surfaces of Galilean moons

    NASA Astrophysics Data System (ADS)

    Galli, A.; Pommerol, A.; Wurz, P.; Jost, B.; Scheer, J. A.; Vorburger, A.; Tulej, M.; Thomas, N.; Wieser, M.; Barabash, S.

    2015-10-01

    We use an existing laboratory facility for space hardware calibration in vacuum to study the impact of energetic ions on water ice. The experiment is intended to simulate the conditions on the surface of Jupiter's icy moons. The first results of hydrogen, oxygen, and sulphur ions sputtering a sample of porous salty ice confirmed extrapolations from previous sputtering experiments obtained at different impact angles for nonporous water ice [3]. Here, we present additional measurements for a larger range of ion impact angles and different ice samples.

  6. Polymers for Drug Delivery Systems

    PubMed Central

    Liechty, William B.; Kryscio, David R.; Slaughter, Brandon V.; Peppas, Nicholas A.

    2012-01-01

    Polymers have played an integral role in the advancement of drug delivery technology by providing controlled release of therapeutic agents in constant doses over long periods, cyclic dosage, and tunable release of both hydrophilic and hydrophobic drugs. From early beginnings using off-the-shelf materials, the field has grown tremendously, driven in part by the innovations of chemical engineers. Modern advances in drug delivery are now predicated upon the rational design of polymers tailored for specific cargo and engineered to exert distinct biological functions. In this review, we highlight the fundamental drug delivery systems and their mathematical foundations and discuss the physiological barriers to drug delivery. We review the origins and applications of stimuli-responsive polymer systems and polymer therapeutics such as polymer-protein and polymer-drug conjugates. The latest developments in polymers capable of molecular recognition or directing intracellular delivery are surveyed to illustrate areas of research advancing the frontiers of drug delivery. PMID:22432577

  7. Analysis of quantum network coding for realistic repeater networks

    NASA Astrophysics Data System (ADS)

    Satoh, Takahiko; Ishizaki, Kaori; Nagayama, Shota; Van Meter, Rodney

    2016-03-01

    Quantum repeater networks have attracted attention for the implementation of long-distance and large-scale sharing of quantum states. Recently, researchers extended classical network coding, which is a technique for throughput enhancement, into quantum information. The utility of quantum network coding (QNC) has been shown under ideal conditions, but it has not been studied previously under conditions of noise and shortage of quantum resources. We analyzed QNC on a butterfly network, which can create end-to-end Bell pairs at twice the rate of the standard quantum network repeater approach. The joint fidelity of creating two Bell pairs has a small penalty for QNC relative to entanglement swapping. It will thus be useful when we care more about throughput than fidelity. We found that the output fidelity drops below 0.5 when the initial Bell pairs have fidelity F <0.90 , even with perfect local gates. Local gate errors have a larger impact on quantum network coding than on entanglement swapping.

  8. The power of the context map: Designing realistic outcome evaluation strategies and other unanticipated benefits.

    PubMed

    Renger, Ralph; Foltysova, Jirina; Becker, Karin L; Souvannasacd, Eric

    2015-10-01

    Developing a feasible evaluation plan is challenging when multiple activities, often sponsored by multiple agencies, work together toward a common goal. Often, resources are limited and not every agency's interest can be represented in the final evaluation plan. The article illustrates how the Antecedent Target Measurement (ATM) approach to logic modeling was adapted to meet this challenge. The key adaptation is the context map generated in the first step of the ATM approach. The context map makes visually explicit many of the underlying conditions contributing to a problem as possible. The article also shares how a prioritization matrix can assist the evaluator in filtering through the context map to prioritize the outcomes to be included in the final evaluation plan as well as creating realistic outcomes. This transparent prioritization process can be especially helpful in managing evaluation expectations of multiple agencies with competing interests. Additional strategic planning benefits of the context map include pinpointing redundancies caused by overlapping collaborative efforts, identifying gaps in coverage, and assisting the coordination of multiple stakeholders. PMID:26036610

  9. Toward More Realistic Analytic Models of the Heliotail: Incorporating Magnetic Flattening via Distortion Flows

    NASA Astrophysics Data System (ADS)

    Kleimann, Jens; Röken, Christian; Fichtner, Horst; Heerikhuisen, Jacob

    2016-01-01

    Both physical arguments and simulations of the global heliosphere indicate that the tailward heliopause is flattened considerably in the direction perpendicular to both the incoming flow and the large-scale interstellar magnetic field. Despite this fact, all of the existing global analytical models of the outer heliosheath's magnetic field assume a circular cross section of the heliotail. To eliminate this inconsistency, we introduce a mathematical procedure by which any analytically or numerically given magnetic field can be deformed in such a way that the cross sections along the heliotail axis attain freely prescribed, spatially dependent values for their total area and aspect ratio. The distorting transformation of this method honors both the solenoidality condition and the stationary induction equation with respect to an accompanying flow field, provided that both constraints were already satisfied for the original magnetic and flow fields prior to the transformation. In order to obtain realistic values for the above parameters, we present the first quantitative analysis of the heliotail's overall distortion as seen in state-of-the-art three-dimensional hybrid MHD-kinetic simulations.

  10. Feasibility study for a realistic training dedicated to radiological protection improvement

    NASA Astrophysics Data System (ADS)

    Courageot, Estelle; Reinald, Kutschera; Gaillard-Lecanu, Emmanuelle; Sylvie, Jahan; Riedel, Alexandre; Therache, Benjamin

    2014-06-01

    Any personnel involved in activities within the controlled area of a nuclear facility must be provided with appropriate radiological protection training. An evident purpose of this training is to know the regulation dedicated to workplaces where ionizing radiation may be present, in order to properly carry out the radiation monitoring, to use suitable protective equipments and to behave correctly if unexpected working conditions happen. A major difficulty of this training consist in having the most realistic reading from the monitoring devices for a given exposure situation, but without using real radioactive sources. A new approach is developed at EDF R&D for radiological protection training. This approach combines different technologies, in an environment representative of the workplace but geographically separated from the nuclear power plant: a training area representative of a workplace, a Man Machine Interface used by the trainer to define the source configuration and the training scenario, a geolocalization system, fictive radiation monitoring devices and a particle transport code able to calculate in real time the dose map due to the virtual sources. In a first approach, our real-time particles transport code, called Moderato, used only an attenuation low in straight line. To improve the realism further, we would like to switch a code based on the Monte Carlo transport of particles method like Geant 4 or MCNPX instead of Moderato. The aim of our study is the evaluation of the code in our application, in particular, the possibility to keep a real time response of our architecture.

  11. Analytical solution to transient Richards' equation with realistic water profiles for vertical infiltration and parameter estimation

    NASA Astrophysics Data System (ADS)

    Hayek, Mohamed

    2016-06-01

    A general analytical model for one-dimensional transient vertical infiltration is presented. The model is based on a combination of the Brooks and Corey soil water retention function and a generalized hydraulic conductivity function. This leads to power law diffusivity and convective term for which the exponents are functions of the inverse of the pore size distribution index. Accordingly, the proposed analytical solution covers many existing realistic models in the literature. The general form of the analytical solution is simple and it expresses implicitly the depth as function of water content and time. It can be used to model infiltration through semi-infinite dry soils with prescribed water content or flux boundary conditions. Some mathematical expressions of practical importance are also derived. The general form solution is useful for comparison between models, validation of numerical solutions and for better understanding the effect of some hydraulic parameters. Based on the analytical expression, a complete inverse procedure which allows the estimation of the hydraulic parameters from water content measurements is presented.

  12. Traces of surfactants limit the drag reduction potential of superhydrophobic surfaces in realistic applications

    NASA Astrophysics Data System (ADS)

    Peaudecerf, Francois J.; Landel, Julien R.; Luzzatto-Fegiz, Paolo

    2015-11-01

    Large drag reductions have been measured for laminar flows over superhydrophobic surfaces (SHS), making them attractive for applications in pipelines, ships and submarines. However, experiments involving turbulent flows, typical of these applications, have often yielded limited drag reductions. A complete explanation for this issue has so far proved elusive. We propose that trace amounts of surfactants, unavoidable in the environment and in large-scale experiments, can yield poor performances of SHS, by producing Marangoni stresses when the edges of the SHS pattern are not aligned with the local flow velocity. To explore our hypothesis, we develop numerical simulations (inclusive of surfactants) for a flow over a textured SHS in a micro-channel, whose background shear is similar to a viscous sublayer. The texture consists of micro ridges perpendicular to the flow. We find that even small amounts of surfactants can prevent any drag reduction. As an experimental test, we flow de-ionised water with known surfactant concentrations through SHS micro-channels with texture similar to the simulations, while performing micro-PIV. At negligible surfactant concentrations, we find higher velocities between the ridges, as expected by classical models. However, as the concentration increases, we discover that the slip velocity drops to very small values even in the presence of a plastron. Our results show that the drag-reducing potential of superhydrophobic surfaces can be limited in realistic flow conditions

  13. Thermomechanical coupling in coarse grained cholesteric liquid crystal model systems with pitches of realistic length.

    PubMed

    Sarman, Sten; Wang, Yong-Lei; Laaksonen, Aatto

    2016-06-22

    Thermomechanical coupling in cholesteric liquid crystals, i.e. when a temperature gradient parallel to the cholesteric axis rotates the director, has been studied in a model system of soft ellipsoids where the interaction potential has been augmented by a chiral potential. More specifically, the cross coupling coefficient between the temperature gradient and the director angular velocity, or Leslie coefficient, has been obtained as a function of the pitch by evaluating the corresponding Green-Kubo relation by molecular dynamics simulation. The product of the Leslie coefficient and the pitch has been found to be constant within the statistical uncertainty. This is in accordance with a symmetry condition originally proposed by de Gennes and it means that the Leslie coefficient of systems with longer pitches can be obtained from systems with shorter pitches. Since the pitches of realistic systems are usually very long, it becomes possible to study thermomechanical coupling in these systems which otherwise would have required prohibitively long simulations. Since we also have obtained rather accurate data on the cross correlation function between the director angular velocity and the heat current density, it becomes possible to analyse the mechanism of thermomechanical coupling to some extent. PMID:27279499

  14. Realistic evaluation of hull performance for rowing shells, canoes, and kayaks in unsteady flow.

    PubMed

    Day, Alexander; Campbell, Ian; Clelland, David; Doctors, Lawrence J; Cichowicz, Jakub

    2011-07-01

    In this study, we investigated the effect of hull dynamics in shallow water on the hydrodynamic performance of rowing shells as well as canoes and kayaks. An approach was developed to generate data in a towing tank using a test rig capable of reproducing realistic speed profiles. The impact of unsteady shallow-water effects on wave-making resistance was examined via experimental measurements on a benchmark hull. The data generated were used to explore the validity of a computational approach developed to predict unsteady shallow-water wave resistance. Comparison of measured and predicted results showed that the computational approach correctly predicted complex unsteady wave-resistance phenomena at low oscillation frequency and speed, but that total resistance was substantially under-predicted at moderate oscillation frequency and speed. It was postulated that this discrepancy arose from unsteady viscous effects. This was investigated via hot-film measurements for a full-scale single scull in unsteady flow in both towing-tank and field-trial conditions. Results suggested a strong link between acceleration and turbulence and demonstrated that the measured real-world viscous-flow behaviour could be successfully reproduced in the tank. Thus a suitable tank-test approach could provide a reliable guide to hull performance characterization in unsteady flow. PMID:21756127

  15. The Toxicological Evaluation of Realistic Emissions of Source Aerosols Study: Statistical Methods

    PubMed Central

    Coull, Brent A.; Wellenius, Gregory A.; Gonzalez-Flecha, Beatriz; Diaz, Edgar; Koutrakis, Petros; Godleski, John J.

    2013-01-01

    The Toxicological Evaluation of Realistic Emissions of Source Aerosols (TERESA) study involved withdrawal, aging, and atmospheric transformation of emissions of three coal-fired power plants. Toxicological evaluations were carried out in rats exposed to different emission scenarios with extensive exposure characterization. Data generated had multiple levels of resolution: exposure, scenario and constituent chemical composition. Here, we outline a multilayered approach to analyze the associations between exposure and health effects beginning with standard ANOVA models that treat exposure as a categorical variable. The model assessed differences in exposure effects across scenarios (by plant). To assess unadjusted associations between pollutant concentrations and health, univariate analyses were conducted using the difference between the response means under exposed and control conditions and a single constituent concentration as the predictor. Then, a novel multivariate analysis of exposure composition and health was used based on random forests, a recent extension of classification and regression trees that were applied to the outcome differences. For each exposure constituent, this approach yielded a nonparametric measure of the importance of that constituent in predicting differences in response on a given day, controlling for the other measured constituent concentrations in the model. Finally, an R2 analysis compared the relative importance of exposure scenario, plant, and constituent concentrations on each outcome. Peak expiratory flow is used to demonstrate how the multiple levels of the analysis complement each other to assess constituents most strongly associated with health effects. PMID:21913820

  16. Toward Establishing a Realistic Benchmark for Airframe Noise Research: Issues and Challenges

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.

    2010-01-01

    The availability of realistic benchmark configurations is essential to enable the validation of current Computational Aeroacoustic (CAA) methodologies and to further the development of new ideas and concepts that will foster the technologies of the next generation of CAA tools. The selection of a real-world configuration, the subsequent design and fabrication of an appropriate model for testing, and the acquisition of the necessarily comprehensive aeroacoustic data base are critical steps that demand great care and attention. In this paper, a brief account of the nose landing-gear configuration, being proposed jointly by NASA and the Gulfstream Aerospace Company as an airframe noise benchmark, is provided. The underlying thought processes and the resulting building block steps that were taken during the development of this benchmark case are given. Resolution of critical, yet conflicting issues is discussed - the desire to maintain geometric fidelity versus model modifications required to accommodate instrumentation; balancing model scale size versus Reynolds number effects; and time, cost, and facility availability versus important parameters like surface finish and installation effects. The decisions taken during the experimental phase of a study can significantly affect the ability of a CAA calculation to reproduce the prevalent flow conditions and associated measurements. For the nose landing gear, the most critical of such issues are highlighted and the compromises made to resolve them are discussed. The results of these compromises will be summarized by examining the positive attributes and shortcomings of this particular benchmark case.

  17. Steady and unsteady transonic small disturbance analysis of realistic aircraft configurations

    NASA Technical Reports Server (NTRS)

    Batina, John T.; Seidel, David A.; Bennett, Robert M.; Cunningham, Herbert J.; Bland, Samuel R.

    1988-01-01

    A transonic unsteady aerodynamic and aeroelasticity code CAP-TSD (Computational Aeroelasticity Program-Transonic Small Disturbance) has been developed for application to realistic aircraft configurations. The code uses a time-accurate approximate factorization (AF) algorithm for solution of the unsteady transonic small-disturbance potential equation. The paper gives an overview of the CAP-TSD code development effort and reports on recent algorithm modifications. The algorithm modifications include: an Engquist-Osher (E-O) type-dependent switch to treat regions of supersonic flow, extension of the E-O switch for second-order spatial accuracy, nonisentropic effects to treat strong-shock cases, nonreflecting far field boundary conditions for unsteady applications, and several modifications to accelerate convergence to steady state. The modifications have significantly improved the stability of the AF algorithm and hence the reliability of the CAP-TSD code in general. Calculations are also presented from a flutter analysis of a 45-deg sweptback wing which agree well with experimental data. The paper present descriptions of the CAP-TSD code and algorithm details along with results.

  18. Evaluation of three-dimensional anisotropic head model for mapping realistic electromagnetic fields of brain tissues

    NASA Astrophysics Data System (ADS)

    Jeong, Woo Chul; Wi, Hun; Sajib, Saurav Z. K.; Oh, Tong In; Kim, Hyung Joong; Kwon, Oh In; Woo, Eung Je

    2015-08-01

    Electromagnetic fields provide fundamental data for the imaging of electrical tissue properties, such as conductivity and permittivity, in recent magnetic resonance (MR)-based tissue property mapping. The induced voltage, current density, and magnetic flux density caused by externally injected current are critical factors for determining the image quality of electrical tissue conductivity. As a useful tool to identify bio-electromagnetic phenomena, precise approaches are required to understand the exact responses inside the human body subject to an injected currents. In this study, we provide the numerical simulation results of electromagnetic field mapping of brain tissues using a MR-based conductivity imaging method. First, we implemented a realistic three-dimensional human anisotropic head model using high-resolution anatomical and diffusion tensor MR images. The voltage, current density, and magnetic flux density of brain tissues were imaged by injecting 1 mA of current through pairs of electrodes on the surface of our head model. The current density map of anisotropic brain tissues was calculated from the measured magnetic flux density based on the linear relationship between the water diffusion tensor and the electrical conductivity tensor. Comparing the current density to the previous isotropic model, the anisotropic model clearly showed the differences between the brain tissues. This originates from the enhanced signals by the inherent conductivity contrast as well as the actual tissue condition resulting from the injected currents.

  19. A more realistic thermal shock analysis of a radially multicracked thick-walled cylinder

    NASA Astrophysics Data System (ADS)

    Perl, M.; Ashkenazi, A.

    1992-07-01

    Presently available analyses of multicracking of thick-walled cylinders due to an internal thermal shock, model the shock by a temperature step-change at the cylinder bore, yielding a considerably overestimated temperature field through the cylinder's wall. In the present work a more realistic thermal shock model is employed assuming convection boundary conditions at both the inner and the outer cylinder surfaces. Transient mode I stress intensity factors (SIF), resulting from the thermal shock during the firing process in a typical gun barrel, are evaluated for large arrays of radial cracks emanating from the bore surface of the cylinder. The transient thermal analysis as well as the computation of the SIFs is performed via the finite element method. Once the thermal problem is solved, SIFs at various time steps are calculated for numerous crack arrays (2-1024) and for a wide range of relevant crack lengths. The present analysis emphasizes the importance of using the proper thermal shock model by showing that the previously available results are nonconservative, and exemplifies the favorable effect of the above thermal shock on the effective SIF prevailing at the tips of these cracks.

  20. Using a non-invasive technique in nutrition: synchrotron radiation infrared microspectroscopy spectroscopic characterization of oil seeds treated with different processing conditions on molecular spectral factors influencing nutrient delivery.

    PubMed

    Zhang, Xuewei; Yu, Peiqiang

    2014-07-01

    Non-invasive techniques are a key to study nutrition and structure interaction. Fourier transform infrared microspectroscopy coupled with a synchrotron radiation source (SR-IMS) is a rapid, non-invasive, and non-destructive bioanalytical technique. To understand internal structure changes in relation to nutrient availability in oil seed processing is vital to find optimal processing conditions. The objective of this study was to use a synchrotron-based bioanalytical technique SR-IMS as a non-invasive and non-destructive tool to study the effects of heat-processing methods and oil seed canola type on modeled protein structure based on spectral data within intact tissue that were randomly selected and quantify the relationship between the modeled protein structure and protein nutrient supply to ruminants. The results showed that the moisture heat-related processing significantly changed (p<0.05) modeled protein structures compared to the raw canola (control) and those processing by dry heating. The moisture heating increased (p<0.05) spectral intensities of amide I, amide II, α-helices, and β-sheets but decreased (p<0.05) the ratio of modeled α-helices to β-sheet spectral intensity. There was no difference (p>0.05) in the protein spectral profile between the raw and dry-heated canola tissue and between yellow- and brown-type canola tissue. The results indicated that different heat processing methods have different impacts on the protein inherent structure. The protein intrinsic structure in canola seed tissue was more sensitive and more response to the moisture heating in comparison to the dry heating. These changes are expected to be related to the nutritive value. However, the current study is based on limited samples, and more large-scale studies are needed to confirm our findings. PMID:24920208

  1. Photomechanical drug delivery

    NASA Astrophysics Data System (ADS)

    Doukas, Apostolos G.; Lee, Shun

    2000-05-01

    Photomechanical waves (PW) are generated by Q-switched or mode-locked lasers. Ablation is a reliable method for generating PWs with consistent characteristics. Depending on the laser wavelength and target material, PWs with different parameters can be generated which allows the investigation of PWs with cells and tissue. PWs have been shown to permeabilize the stratum corneum (SC) in vivo and facilitate the transport of drugs into the skin. Once a drug has diffused into the dermis it can enter the vasculature, thus producing a systemic effect. Fluorescence microscopy of biopsies show that 40-kDa molecules can be delivered to a depth of > 300 micrometers into the viable skin of rats. Many important drugs such as insulin, and erythropoietin are smaller or comparable in size, making the PWs attractive for transdermal drug delivery. There are three possible pathways through the SC: Transappendageal via hair follicles or other appendages, transcellular through the corneocytes, and intercellular via the extracellular matrix. The intracellular route appears to be the most likely pathway of drug delivery through the SC.

  2. Predictive atomistic simulations of electronic properties of realistic nanoscale devices: A multiscale modeling approach

    NASA Astrophysics Data System (ADS)

    Vedula, Ravi Pramod Kumar

    Scaling of CMOS towards its ultimate limits, where quantum effects and atomistic variability due to fabrication, along with recent emphasis on heterogeneous integration of non-digital devices for increasing the functional diversification presents us with fundamentally new challenges. A comprehensive understanding of design and operation of these nanoscale transistors, and other electronic devices like RF-MEMS, requires an insight into their electronic and mechanical properties that are strongly influenced by underlying atomic structure. Hence, continuum descriptions of materials and use of empirical models at these scales become questionable. This increase in complexity of electronic devices necessitates an understanding at a more fundamental level to accurately predict the performance and reliability of these devices. The objective of this thesis is to outline the application of multiscale predictive modeling methods, ranging from atoms to devices, for addressing these challenges. This capability is demonstrated using two examples: characterization of (i) dielectric charging in RF-MEMS, and (ii) transport properties of Ge-nanofins. For characterizing the dielectric charging phenomenon, a continuum dielectric charging model, augmented by first principles informed trap distributions, is used to predict current transient measurements across a broad range of voltages and temperatures. These simulations demonstrate using ab initio informed model not only reduces the empiricism (number of adjustable parameters) in the model but also leads to a more accurate model over a broad range of operating conditions, and enable the precise determination of additional material parameters. These atomistic calculations also provide detailed information about the nature of charge traps and their trapping mechanisms that are not accessible experimentally; such information could prove invaluable in defect engineering. The second problem addresses the effect of the in-homogeneous strain

  3. Ice Nuclei Emissions From Sea Spray Produced By Realistically Simulated Breaking Waves

    NASA Astrophysics Data System (ADS)

    Sullivan, R. C.; DeMott, P. J.; Ruppel, M. J.; Franc, G.; Hill, T.; Collins, D. B.; Cuadra-Rodriguez, L. A.; Guasco, T.; Kim, M. J.; Ault, A. P.; Grassian, V. H.; Prather, K. A.

    2012-12-01

    Breaking waves were used to generate realistic sea spray aerosol in the laboratory for the first time to study the chemical and cloud nucleation properties of marine-derived particles. Ice nuclei (IN) concentrations were measured online from the large wave channel, and from a smaller wave tank, during the collaborative CAICE experiment at Scripps Institution of Oceanography. These represent the first such measurements of ice nucleation isolated to sea spray aerosol under controlled but realistic laboratory conditions. The wave channel and small wave tank were filled with coarsely filtered sea water pumped from the nearby Pacific Ocean. Various types of bacteria, phytoplankton, and/or algae were added to the tanks to simulate marine biology. In a multiday mesocosm experiment, growth media was also added to stimulate a marine bloom event. Ice nuclei concentrations were strongly dependent on the cloud processing temperature, and required a combination of both online and higher sample volume offline collection methods to successfully characterize IN concentrations at the warmest ice nucleation temperatures. A clear relation between ice nuclei concentrations at lower temperatures below -30 °C and heterotrophic bacteria concentrations in the seawater was found. The IN concentration was also impaired by increasing concentrations of total organic carbon. IN did not correlate with chlorophyll concentrations, though this is the indicator typically used to predict changes in ocean biology and chemistry and the resulting alteration of sea spray aerosol properties. Spectromicroscopic analysis of collected ice crystals was used to investigate what particle compositions were likely responsible for the observed ice nucleation activity. These measurements suggest characteristic ice nuclei activation at lower average temperatures than typically observed for Northern Hemisphere ambient aerosols. The marine bio-particles observed here displayed weaker ice nucleation ability than

  4. Physical enhancement of transdermal drug application: is delivery technology keeping up with pharmaceutical development?

    PubMed

    Cross, S E; Roberts, M S

    2004-01-01

    Advances in molecular biology have given us a wide range of protein and peptide-based drugs that are unsuitable for oral delivery because of their high degree of first-pass metabolism. Though parenteral delivery is the obvious answer, for the successful development of commercial chronic and self-administration usage formulations it is not the ideal choice. Transdermal delivery is emerging as the biggest application target for these agents, however, the skin is extremely efficient at keeping out such large molecular weight compounds and therapeutic levels are never going to be realistically achieved by passive absorption. Physical enhancement mechanisms including: iontophoresis, electroporation, ultrasound, photomechanical waves, microneedles and jet-propelled particles are emerging as solutions to this topical delivery dilemma. Adding proteins and peptides to the list of other large molecular weight drugs with insufficient passive transdermal fluxes to be therapeutically useful, we have a collection of pharmacological agents waiting for efficient delivery methods to be introduced. This article reviews the current state of physical transdermal delivery technology, assesses the pros and cons of each technique and summarises the evidence-base of their drug delivery capabilities. PMID:16305373

  5. Delivery methods for LVSD systems

    NASA Astrophysics Data System (ADS)

    Kasner, James H.; Brower, Bernard V.

    2011-06-01

    In this paper we present formats and delivery methods of Large Volume Streaming Data (LVSD) systems. LVSD systems collect TBs of data per mission with aggregate camera sizes in the 100 Mpixel to several Gpixel range at temporal rates of 2 - 60 Hz. We present options and recommendations for the different stages of LVSD data collection and delivery, to include the raw (multi-camera) data, delivery of processed (stabilized mosaic) data, and delivery of user-defined region of interest windows. Many LVSD systems use JPEG 2000 for the compression of raw and processed data. We explore the use of the JPEG 2000 Interactive Protocol (JPIP) for interactive client/server delivery to thick-clients (desktops and laptops) and MPEG-2 and H.264 to handheld thin-clients (tablets, cell phones). We also explore the use of 3D JPEG 2000 compression, defined in ISO 15444-2, for storage and delivery as well. The delivery of raw, processed, and region of interest data requires different metadata delivery techniques and metadata content. Beyond the format and delivery of data and metadata we discuss the requirements for a client/server protocol that provides data discovery and retrieval. Finally, we look into the future as LVSD systems perform automated processing to produce "information" from the original data. This information may include tracks of moving targets, changes of the background, snap shots of targets, fusion of multiple sensors, and information about "events" that have happened.

  6. Modified montmorillonite as vector for gene delivery.

    PubMed

    Lin, Feng-Huei; Chen, Chia-Hao; Cheng, Winston T K; Kuo, Tzang-Fu

    2006-06-01

    Currently, gene delivery systems can be divided into two parts: viral or non-viral vectors. In general, viral vectors have a higher efficiency on gene delivery. However, they may sometimes provoke mutagenesis and carcinogenesis once re-activating in human body. Lots of non-viral vectors have been developed that tried to solve the problems happened on viral vectors. Unfortunately, most of non-viral vectors showed relatively lower transfection rate. The aim of this study is to develop a non-viral vector for gene delivery system. Montmorillonite (MMT) is one of clay minerals that consist of hydrated aluminum with Si-O tetrahedrons on the bottom of the layer and Al-O(OH)2 octahedrons on the top. The inter-layer space is about 12 A. The room is not enough to accommodate DNA for gene delivery. In the study, the cationic hexadecyltrimethylammonium (HDTMA) will be intercalated into the interlayer of MMT as a layer expander to expand the layer space for DNA accommodation. The optimal condition for the preparation of DNA-HDTMA-MMT is as follows: 1 mg of 1.5CEC HDTMA-MMT was prepared under pH value of 10.7 and with soaking time for 2 h. The DNA molecules can be protected from nuclease degradation, which can be proven by the electrophoresis analysis. DNA was successfully transfected into the nucleus of human dermal fibroblast and expressed enhanced green fluorescent protein (EGFP) gene with green fluorescence emission. The HDTMA-MMT has a great potential as a vector for gene delivery in the future. PMID:16488006

  7. Obstructed Defecation Syndrome After Delivery Trauma

    PubMed Central

    Mehrvarz, Shaban; Towliat, Seyed Mohsem; Mohebbi, Hassan Ali; Heydari, Soleyman; Farahani, Mahdi; Rasouli, Hamid Reza

    2015-01-01

    Background: Obstructed defecation syndrome (ODS) occurs in about 7% of adults; it seems that the etiology of pelvic floor disorders is multifactorial. Pregnancy and childbirth damage to the pelvic nerve and muscles are proposed causes for this condition. The precise role of vaginal delivery (VD) is not clearly defined, although in recent studies association of pelvic floor disorder with Operative vaginal delivery and episiotomy has been proposed. Objectives: In this prospective study, we assessed the outcome of stapled transanal rectal resection (STARR) in females with one of the two modes of delivery (VD or caesarean section (C/S). Patients and Methods: We used Longo’s ODS score for the assessment of the severity of pelvic floor malfunction. Stapled Trans Anal Rectal Resection (STARR) procedure was performed using two circular staplers. Follow-up was done 12 months after the discharge. To assess the role of episiotomy in patient with VD, we divided them into two subgroups; females who had VD with episiotomy (Vd + epi) and females who had VD alone. Data were analyzed using SPSS version 20 software. P values less than 0.05 were considered statistically significant. Results: In 30 consecutive females undergoing STARR for the treatment of ODS, who enrolled in this prospective study, 19 (63.3%) had Vaginal Delivery VD and 11 (36.7%) had Cesarean Section (C/S). The ODS score before the surgery was higher in females who had C/S, although there was no significant difference between VD and C/S groups in terms of the percentage of the ODS score improvement after the STARR surgery. Conclusions: Higher ODS score in females who had C/S showed that C/S could not protect the pelvic organ from pregnancy and delivery trauma. It seems that episiotomy has a protective effect during VD; it can reduce the severity of trauma in pelvic organs during childbearing. PMID:26839863

  8. Chitosan Microspheres in Novel Drug Delivery Systems

    PubMed Central

    Mitra, Analava; Dey, Baishakhi

    2011-01-01

    The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems. PMID:22707817

  9. Is Carbon a Realistic Choice for ITER's Divertor?

    SciTech Connect

    C.H. Skinner; G. Federici

    2005-05-13

    Tritium retention by co-deposition with carbon on the divertor target plate is predicted to limit ITER's DT burning plasma operations (e.g. to about 100 pulses for the worst conditions) before the in-vessel tritium inventory limit, currently set at 350 g, is reached. At this point, ITER will only be able to continue its burning plasma program if technology is available that is capable of rapidly removing large quantities of tritium from the vessel with over 90% efficiency. The removal rate required is four orders of magnitude faster than that demonstrated in current tokamaks. Eighteen years after the observation of co-deposition on JET and TFTR, such technology is nowhere in sight. The inexorable conclusion is that either a major initiative in tritium removal should be funded or that research priorities for ITER should focus on metal alternatives.

  10. Towards effective flow simulations in realistic discrete fracture networks

    NASA Astrophysics Data System (ADS)

    Berrone, Stefano; Pieraccini, Sandra; Scialò, Stefano

    2016-04-01

    We focus on the simulation of underground flow in fractured media, modeled by means of Discrete Fracture Networks. Focusing on a new recent numerical approach proposed by the authors for tackling the problem avoiding mesh generation problems, we further improve the new family of methods making a step further towards effective simulations of large, multi-scale, heterogeneous networks. Namely, we tackle the imposition of Dirichlet boundary conditions in weak form, in such a way that geometrical complexity of the DFN is not an issue; we effectively solve DFN problems with fracture transmissivities spanning many orders of magnitude and approaching zero; furthermore, we address several numerical issues for improving the numerical solution also in quite challenging networks.

  11. Realistic uncertainties on Hapke model parameters from photometric measurement

    NASA Astrophysics Data System (ADS)

    Schmidt, Frédéric; Fernando, Jennifer

    2015-11-01

    The single particle phase function describes the manner in which an average element of a granular material diffuses the light in the angular space usually with two parameters: the asymmetry parameter b describing the width of the scattering lobe and the backscattering fraction c describing the main direction of the scattering lobe. Hapke proposed a convenient and widely used analytical model to describe the spectro-photometry of granular materials. Using a compilation of the published data, Hapke (Hapke, B. [2012]. Icarus 221, 1079-1083) recently studied the relationship of b and c for natural examples and proposed the hockey stick relation (excluding b > 0.5 and c > 0.5). For the moment, there is no theoretical explanation for this relationship. One goal of this article is to study a possible bias due to the retrieval method. We expand here an innovative Bayesian inversion method in order to study into detail the uncertainties of retrieved parameters. On Emission Phase Function (EPF) data, we demonstrate that the uncertainties of the retrieved parameters follow the same hockey stick relation, suggesting that this relation is due to the fact that b and c are coupled parameters in the Hapke model instead of a natural phenomena. Nevertheless, the data used in the Hapke (Hapke, B. [2012]. Icarus 221, 1079-1083) compilation generally are full Bidirectional Reflectance Diffusion Function (BRDF) that are shown not to be subject to this artifact. Moreover, the Bayesian method is a good tool to test if the sampling geometry is sufficient to constrain the parameters (single scattering albedo, surface roughness, b, c , opposition effect). We performed sensitivity tests by mimicking various surface scattering properties and various single image-like/disk resolved image, EPF-like and BRDF-like geometric sampling conditions. The second goal of this article is to estimate the favorable geometric conditions for an accurate estimation of photometric parameters in order to provide

  12. ‘Including health in systems responsible for urban planning’: a realist policy analysis research programme

    PubMed Central

    Harris, Patrick; Friel, Sharon; Wilson, Andrew

    2015-01-01

    Introduction Realist methods are increasingly being used to investigate complex public health problems. Despite the extensive evidence base clarifying the built environment as a determinant of health, there is limited knowledge about how and why land-use planning systems take on health concerns. Further, the body of research related to the wider determinants of health suffers from not using political science knowledge to understand how to influence health policy development and systems. This 4-year funded programme of research investigates how the land-use planning system in New South Wales, Australia, incorporates health and health equity at multiple levels. Methods and analysis The programme uses multiple qualitative methods to develop up to 15 case studies of different activities of the New South Wales land-use planning system. Comparison cases from other jurisdictions will be included where possible and useful. Data collection includes publicly available documentation and purposively sampled stakeholder interviews and focus groups of up to 100 participants across the cases. The units of analysis in each case are institutional structures (rules and mandates constraining and enabling actors), actors (the stakeholders, organisations and networks involved, including health-focused agencies), and ideas (policy content, information, and framing). Data analysis will focus on and develop propositions concerning the mechanisms and conditions within and across each case leading to inclusion or non-inclusion of health. Data will be refined using additional political science and sociological theory. Qualitative comparative analysis will compare cases to develop policy-relevant propositions about the necessary and sufficient conditions needed to include health issues. Ethics and dissemination Ethics has been approved by Sydney University Human Research Ethics Committee (2014/802 and 2015/178). Given the nature of this research we will incorporate stakeholders, often as

  13. Engineered Polymers for Advanced Drug Delivery

    PubMed Central

    Kim, Sungwon; Kim, Jong-Ho; Jeon, Oju; Kwon, Ick Chan; Park, Kinam

    2009-01-01

    Engineered polymers have been utilized for developing advanced drug delivery systems. The development of such polymers has caused advances in polymer chemistry, which, in turn, has resulted in smart polymers that can respond to changes in environmental condition, such as temperature, pH, and biomolecules. The responses vary widely from swelling/deswelling to degradation. Drug-polymer conjugates and drug-containing nano/micro-particles have been used for drug targeting. Engineered polymers and polymeric systems have also been used in new areas, such as molecular imaging as well as in nanotechnology. This review examines the engineered polymers that have been used as traditional drug delivery and as more recent applications in nanotechnology. PMID:18977434

  14. Numerical investigation of physiologically realistic pulsatile flow through arterial stenosis.

    PubMed

    Long, Q; Xu, X Y; Ramnarine, K V; Hoskins, P

    2001-10-01

    Numerical simulations of pulsatile blood flow in straight tube stenosis models were performed to investigate the poststenotic flow phenomena. In this study, three axisymmetrical and three asymmetrical stenosis models with area reduction of 25%, 50% and 75% were constructed. A measured human common carotid artery blood flow waveform was used as the upstream flow condition which has a mean Reynold's number of 300. All calculations were performed with high spatial and temporal resolutions. Flow features such as velocity profiles, flow separation zone (FSZ), and wall shear stress (WSS) distributions in the poststenotic region for all models are presented. The results have demonstrated that the formation and development of FSZs in the poststenotic region are very complex, especially in the flow deceleration phase. In axisymmetric stenoses the poststenotic flow is more sensitive to changes in the degree of stenosis than in asymmetric models. For severe stenoses, the stenosis influence length is shorter in asymmetrical models than in axisymmetrical cases. WSS oscillations (between positive and negative values) have been observed at various downstream locations in some models. The amplitude of the oscillation depends strongly on the axial location and the degree of stenosis. PMID:11522303

  15. Microsystems Technologies for Drug Delivery to the Inner Ear

    PubMed Central

    Leary Pararas, Erin E.; Borkholder, David A.; Borenstein, Jeffrey T.

    2012-01-01

    The inner ear represents one of the most technologically challenging targets for local drug delivery, but its clinical significance is rapidly increasing. The prevalence of sensorineural hearing loss and other auditory diseases, along with balance disorders and tinnitus, has spurred broad efforts to develop therapeutic compounds and regenerative approaches to treat these conditions, necessitating advances in systems capable of targeted and sustained drug delivery. The delicate nature of hearing structures combined with the relative inaccessibility of the cochlea by means of conventional delivery routes together necessitate significant advancements in both the precision and miniaturization of delivery systems, and the nature of the molecular and cellular targets for these therapies suggests that multiple compounds may need to be delivered in a time-sequenced fashion over an extended duration. Here we address the various approaches being developed for inner ear drug delivery, including micropump-based devices, reciprocating systems, and cochlear prosthesis-mediated delivery, concluding with an analysis of emerging challenges and opportunities for the first generation of technologies suitable for human clinical use. These developments represent exciting advances that have the potential to repair and regenerate hearing structures in millions of patients for whom no currently available medical treatments exist, a situation that requires them to function with electronic hearing augmentation devices or to live with severely impaired auditory function. These advances also have the potential for broader clinical applications that share similar requirements and challenges with the inner ear, such as drug delivery to the central nervous system. PMID:22386561

  16. Larval Dispersal Modeling of Pearl Oyster Pinctada margaritifera following Realistic Environmental and Biological Forcing in Ahe Atoll Lagoon

    PubMed Central

    Thomas, Yoann; Dumas, Franck; Andréfouët, Serge

    2014-01-01

    Studying the larval dispersal of bottom-dwelling species is necessary to understand their population dynamics and optimize their management. The black-lip pearl oyster (Pinctada margaritifera) is cultured extensively to produce black pearls, especially in French Polynesia's atoll lagoons. This aquaculture relies on spat collection, a process that can be optimized by understanding which factors influence larval dispersal. Here, we investigate the sensitivity of P. margaritifera larval dispersal kernel to both physical and biological factors in the lagoon of Ahe atoll. Specifically, using a validated 3D larval dispersal model, the variability of lagoon-scale connectivity is investigated against wind forcing, depth and location of larval release, destination location, vertical swimming behavior and pelagic larval duration (PLD) factors. The potential connectivity was spatially weighted according to both the natural and cultivated broodstock densities to provide a realistic view of connectivity. We found that the mean pattern of potential connectivity was driven by the southwest and northeast main barotropic circulation structures, with high retention levels in both. Destination locations, spawning sites and PLD were the main drivers of potential connectivity, explaining respectively 26%, 59% and 5% of the variance. Differences between potential and realistic connectivity showed the significant contribution of the pearl oyster broodstock location to its own dynamics. Realistic connectivity showed larger larval supply in the western destination locations, which are preferentially used by farmers for spat collection. In addition, larval supply in the same sectors was enhanced during summer wind conditions. These results provide new cues to understanding the dynamics of bottom-dwelling populations in atoll lagoons, and show how to take advantage of numerical models for pearl oyster management. PMID:24740288

  17. Realistic Hot Water Draw Specification for Rating Solar Water Heaters: Preprint

    SciTech Connect

    Burch, J.

    2012-06-01

    In the United States, annual performance ratings for solar water heaters are simulated, using TMY weather and specified water draw. A more-realistic ratings draw is proposed that eliminates most bias by improving mains inlet temperature and by specifying realistic hot water use. This paper outlines the current and the proposed draws and estimates typical ratings changes from draw specification changes for typical systems in four cities.

  18. Can realistic interaction be useful for nuclear mean-field approaches?

    NASA Astrophysics Data System (ADS)

    Nakada, H.; Sugiura, K.; Inakura, T.; Margueron, J.

    2016-07-01

    Recent applications of the M3Y-type semi-realistic interaction to the nuclear mean-field approaches are presented: i) Prediction of magic numbers and ii) isotope shifts of nuclei with magic proton numbers. The results exemplify that the realistic interaction, which is derived from the bare 2 N and 3 N interaction, furnishes a new theoretical instrument for advancing nuclear mean-field approaches.

  19. Economical ground data delivery

    NASA Technical Reports Server (NTRS)

    Markley, Richard W.; Byrne, Russell H.; Bromberg, Daniel E.

    1994-01-01

    Data delivery in the Deep Space Network (DSN) involves transmission of a small amount of constant, high-priority traffic and a large amount of bursty, low priority data. The bursty traffic may be initially buffered and then metered back slowly as bandwidth becomes available. Today both types of data are transmitted over dedicated leased circuits. The authors investigated the potential of saving money by designing a hybrid communications architecture that uses leased circuits for high-priority network communications and dial-up circuits for low-priority traffic. Such an architecture may significantly reduce costs and provide an emergency backup. The architecture presented here may also be applied to any ground station-to-customer network within the range of a common carrier. The authors compare estimated costs for various scenarios and suggest security safeguards that should be considered.

  20. Intrathecal delivery of analgesics.

    PubMed

    De Andres, Jose; Asensio-Samper, Juan Marcos; Fabregat-Cid, Gustavo

    2014-01-01

    Targeted intrathecal (IT) drug delivery systems (IDDS) are an option in algorithms for the treatment of patients with moderate to severe chronic refractory pain when more conservative options fail. This therapy is well established and supported by several publications. It has shown efficacy and is an important tool for the treatment of spasticity, and both cancer and nonmalignant pain. Recent technological advances, new therapeutic applications, reported complications, and the costs as well as maintenance required for this therapy require the need to stay up-to-date about new recommendations that may improve outcomes. This chapter reviews all technological issues regarding IDDS implantation with follow-up, and pharmacological recommendations published during recent years that provide evidence-based decision making process in the management of chronic pain and spasticity in patients. PMID:24567144

  1. Secondary fuel delivery system

    DOEpatents

    Parker, David M.; Cai, Weidong; Garan, Daniel W.; Harris, Arthur J.

    2010-02-23

    A secondary fuel delivery system for delivering a secondary stream of fuel and/or diluent to a secondary combustion zone located in the transition piece of a combustion engine, downstream of the engine primary combustion region is disclosed. The system includes a manifold formed integral to, and surrounding a portion of, the transition piece, a manifold inlet port, and a collection of injection nozzles. A flowsleeve augments fuel/diluent flow velocity and improves the system cooling effectiveness. Passive cooling elements, including effusion cooling holes located within the transition boundary and thermal-stress-dissipating gaps that resist thermal stress accumulation, provide supplemental heat dissipation in key areas. The system delivers a secondary fuel/diluent mixture to a secondary combustion zone located along the length of the transition piece, while reducing the impact of elevated vibration levels found within the transition piece and avoiding the heat dissipation difficulties often associated with traditional vibration reduction methods.

  2. Topical delivery of hexamidine.

    PubMed

    Parisi, Nicola; Paz-Alvarez, Miguel; Matts, Paul J; Lever, Rebecca; Hadgraft, Jonathan; Lane, Majella E

    2016-06-15

    Hexamidine diisethionate (HEX D) has been used for its biocidal actions in topical preparations since the 1950s. Recent data also suggest that it plays a beneficial role in skin homeostasis. To date, the extent to which this compound penetrates the epidermis has not been reported nor how its topical delivery may be modulated. In the present work we set out to characterise the interaction of HEX D with the skin and to develop a range of simple formulations for topical targeting of the active. A further objective was to compare the skin penetration of HEX D with its corresponding dihydrochloride salt (HEX H) as the latter has more favourable physicochemical properties for skin uptake. Candidate vehicles were evaluated by in vitro Franz cell permeation studies using porcine skin. Initially, neat solvents were investigated and subsequently binary systems were examined. The solvents and chemical penetration enhancers investigated included glycerol, dimethyl isosorbide (DMI), isopropyl alcohol (IPA), 1,2-pentanol (1,2-PENT), polyethylene glycol (PEG) 200, propylene glycol (PG), propylene glycol monolaurate (PGML) and Transcutol(®)P (TC). Of a total of 30 binary solvent systems evaluated only 10 delivered higher amounts of active into the skin compared with the neat solvents. In terms of topical efficacy, formulations containing PGML far surpassed all other solvents or binary combinations. More than 70% of HEX H was extracted from the skin following application in PG:PGML (50:50). Interestingly, the same vehicle effectively promoted skin penetration of HEX D but demonstrated significantly lower uptake into and through the skin (30%). The findings confirm the unpredictable nature of excipients on delivery of actives with reference to skin even where there are minor differences in molecular structures. We also believe that they underline the ongoing necessity for fundamental studies on the interaction of topical excipients with the skin. PMID:27130367

  3. Hydrogen Delivery Technical Team Roadmap

    SciTech Connect

    2013-06-01

    The mission of the Hydrogen Delivery Technical Team (HDTT) is to enable the development of hydrogen delivery technologies, which will allow for fuel cell competitiveness with gasoline and hybrid technologies by achieving an as-produced, delivered, and dispensed hydrogen cost of $2-$4 per gallon of gasoline equivalent of hydrogen.

  4. Hydrogen Distribution and Delivery Infrastructure

    SciTech Connect

    2008-11-01

    This 2-page fact sheet provides a brief introduction to hydrogen delivery technologies. Intended for a non-technical audience, it explains how hydrogen is transported and delivered today, the challenges to delivering hydrogen for use as a widespread energy carrier, and the research goals for hydrogen delivery.

  5. Chemical Abstracts' Document Delivery Service.

    ERIC Educational Resources Information Center

    Rollins, Stephen

    1984-01-01

    The Document Delivery Service offered by Chemical Abstracts is described in terms of the DIALORDER option on the Dialog information retrieval system, mail requests, and requests transmitted through OCLC's Interlibrary Loan system. Transmission costs, success rates, delivery rates, and other considerations in utilizing the service are included.…

  6. The Bankruptcy of Service Delivery.

    ERIC Educational Resources Information Center

    Seeley, David S.

    The dominant concept of public education at present can be described as a "service delivery" model. The public wants its children educated, delegates the job to a government agency (the schools), and holds that agency responsible for the delivery of educational services. The problems in public education, however, will not be solved by holding the…

  7. Advances in the applications of polyhydroxyalkanoate nanoparticles for novel drug delivery system.

    PubMed

    Shrivastav, Anupama; Kim, Hae-Yeong; Kim, Young-Rok

    2013-01-01

    Drug delivery technology is emerging as an interdisciplinary science aimed at improving human health. The controlled delivery of pharmacologically active agents to the specific site of action at the therapeutically optimal rate and dose regimen has been a major goal in designing drug delivery systems. Over the past few decades, there has been considerable interest in developing biodegradable drug carriers as effective drug delivery systems. Polymeric materials from natural sources play an important role in controlled release of drug at a particular site. Polyhydroxyalkanoates, due to their origin from natural sources, are given attention as candidates for drug delivery materials. Biodegradable and biocompatible polyhydroxyalkanoates are linear polyesters produced by microorganisms under unbalanced growth conditions, which have emerged as potential polymers for use as biomedical materials for drug delivery due to their unique physiochemical and mechanical properties. This review summarizes many of the key findings in the applications of polyhydroxyalkanoates and polyhydroxyalkanoate nanoparticles for drug delivery system. PMID:23984383

  8. Advances in the Applications of Polyhydroxyalkanoate Nanoparticles for Novel Drug Delivery System

    PubMed Central

    Shrivastav, Anupama; Kim, Hae-Yeong; Kim, Young-Rok

    2013-01-01

    Drug delivery technology is emerging as an interdisciplinary science aimed at improving human health. The controlled delivery of pharmacologically active agents to the specific site of action at the therapeutically optimal rate and dose regimen has been a major goal in designing drug delivery systems. Over the past few decades, there has been considerable interest in developing biodegradable drug carriers as effective drug delivery systems. Polymeric materials from natural sources play an important role in controlled release of drug at a particular site. Polyhydroxyalkanoates, due to their origin from natural sources, are given attention as candidates for drug delivery materials. Biodegradable and biocompatible polyhydroxyalkanoates are linear polyesters produced by microorganisms under unbalanced growth conditions, which have emerged as potential polymers for use as biomedical materials for drug delivery due to their unique physiochemical and mechanical properties. This review summarizes many of the key findings in the applications of polyhydroxyalkanoates and polyhydroxyalkanoate nanoparticles for drug delivery system. PMID:23984383

  9. Polymer Particulates in Drug Delivery.

    PubMed

    Kaur, Harmeet; Kumar, Virender; Kumar, Krishan; Rathor, Sandeep; Kumari, Parveen; Singh, Jasbir

    2016-01-01

    Development of effective drug delivery systems is important for medicine and healthcare. Polymer particulates (micro- and nanoparticles) have opened new opportunities in the field of drug delivery by overcoming various limitations of conventional delivery methods. The properties of polymeric particles can be readily tuned by precisely engineering the constituent blocks of polymers for improving drug loading, release rate, pharmacokinetics, targeting, etc. The end-groups of various polymers can be readily modified with ligands making them suitable for recognizing by cell-specific receptors, providing cellular specificity, and superior intracellular delivery. This review will mainly cover delivery of many potential drugs and biomolecules by means of polymeric microparticles, nanoparticles and copolymer micelles or assemblies. An overview about formulation methods of polymer particulates has also been addressed. Attempt has been made to cover all the potential polymers that are well known in pharmaceutical history. PMID:26898740

  10. Novel Delivery Strategies for Glioblastoma

    PubMed Central

    Zhou, Jiangbing; Atsina, Kofi-Buaku; Himes, Benjamin T.; Strohbehn, Garth W.; Saltzman, W. Mark

    2012-01-01

    Brain tumors—particularly glioblastoma multiforme (GBM)—pose an important public health problem in the US. Despite surgical and medical advances, the prognosis for patients with malignant gliomas remains grim: current therapy for is insufficient with nearly universal recurrence. A major reason for this failure is the difficulty of delivering therapeutic agents to the brain: better delivery approaches are needed to improve treatment. In this article, we summarize recent progress in drug delivery to the brain, with an emphasis on convection-enhanced delivery of nanocarriers. We examine the potential of new delivery methods to permit novel drug- and gene-based therapies that target brain cancer stem cells (BCSCs) and discuss the use of nanomaterials for imaging of tumors and drug delivery. PMID:22290262

  11. Challenges and opportunities in dermal/transdermal delivery

    PubMed Central

    Paudel, Kalpana S; Milewski, Mikolaj; Swadley, Courtney L; Brogden, Nicole K; Ghosh, Priyanka; Stinchcomb, Audra L

    2010-01-01

    Transdermal drug delivery is an exciting and challenging area. There are numerous transdermal delivery systems currently available on the market. However, the transdermal market still remains limited to a narrow range of drugs. Further advances in transdermal delivery depend on the ability to overcome the challenges faced regarding the permeation and skin irritation of the drug molecules. Emergence of novel techniques for skin permeation enhancement and development of methods to lessen skin irritation would widen the transdermal market for hydrophilic compounds, macromolecules and conventional drugs for new therapeutic indications. As evident from the ongoing clinical trials of a wide variety of drugs for various clinical conditions, there is a great future for transdermal delivery of drugs. PMID:21132122

  12. Getting the most from gene delivery by repeated DNA transfections

    NASA Astrophysics Data System (ADS)

    Montani, Maura; Marchini, Cristina; Badillo Pazmay, Gretta Veronica; Andreani, Cristina; Bartolacci, Caterina; Amici, Augusto; Pozzi, Daniela; Caracciolo, Giulio

    2015-06-01

    Intracellular delivery of reporter genes causes cells to be luminescent or fluorescent, this condition being of tremendous relevance in applied physics research. Potential applications range from the study of spatial distribution and dynamics of plasma membrane and cytosolic proteins up to the rational design of nanocarriers for gene therapy. Since efficiency of gene delivery is the main limit in most biophysical studies, versatile methods that can maximize gene expression are urgently needed. Here, we describe a robust methodology based on repeated gene delivery in mammalian cells. We find this procedure to be much more efficient than the more traditional route of gene delivery making it possible to get high-quality data without affecting cell viability. Implications for biophysical investigations are discussed.

  13. Nanoparticle-based drug delivery to the vagina: a review

    PubMed Central

    Ensign, Laura M.; Cone, Richard; Hanes, Justin

    2014-01-01

    Vaginal drug administration can improve prophylaxis and treatment of many conditions affecting the female reproductive tract, including sexually transmitted diseases, fungal and bacterial infections, and cancer. However, achieving sustained local drug concentrations in the vagina can be challenging, due to the high permeability of the vaginal epithelium and expulsion of conventional soluble drug dosage forms. Nanoparticle-based drug delivery platforms have received considerable attention for vaginal drug delivery, as nanoparticles can provide sustained release, cellular targeting, and even intrinsic antimicrobial or adjuvant properties that can improve the potency and/or efficacy of prophylactic and therapeutic modalities. Here, we review the use of polymeric nanoparticles, liposomes, dendrimers, and inorganic nanoparticles for vaginal drug delivery. Although most of the work toward nanoparticle-based drug delivery in the vagina has been focused on HIV prevention, strategies for treatment and prevention of other sexually transmitted infections, treatment for reproductive tract cancer, and treatment of fungal and bacterial infections are also highlighted. PMID:24830303

  14. Race, genes and preterm delivery.

    PubMed Central

    Fiscella, Kevin

    2005-01-01

    High rates of preterm delivery (PTD) among African Americans are the leading cause of excess infant mortality among African Americans. Failure to fully explain racial disparity in PTD has led to speculation that genetic factors might contribute to this disparity. Current evidence suggests that genetic factors contribute to PTD, but this does not imply that genetic factors contribute to racial disparity in PTD. Environmental factors clearly contribute to PTD. Many of these factors acting over a women's life prior to pregnancy disproportionately affect African Americans and contribute significantly to racial disparity in PTD. Thus, inferring genetic contribution to racial disparity in PTD by attempting to control for environmental factors measured at a single point in time is flawed. There is emerging evidence of gene-environment interactions for PTD, some of which disproportionately affect African Americans. There is also evidence of racial differences in the prevalence of polymorphisms potentially related to PTD. However, to date there is no direct evidence that these differences contribute significantly to racial disparity in PTD. Given the complexity of polygenic conditions such as PTD, the possibility of any single gene contributing substantially to racial disparity in PTD seems remote. PMID:16334498

  15. Protease-mediated drug delivery

    NASA Astrophysics Data System (ADS)

    Dickson, Eva F.; Goyan, Rebecca L.; Kennedy, James C.; Mackay, M.; Mendes, M. A. K.; Pottier, Roy H.

    2003-12-01

    Drugs used in disease treatment can cause damage to both malignant and normal tissue. This toxicity limits the maximum therapeutic dose. Drug targeting is of high interest to increase the therapeutic efficacy of the drug without increasing systemic toxicity. Certain tissue abnormalities, disease processes, cancers, and infections are characterized by high levels of activity of specific extracellular and/or intracellular proteases. Abnormally high activity levels of specific proteases are present at sites of physical or chemical trauma, blood clots, malignant tumors, rheumatoid arthritis, inflammatory bowel disease, gingival disease, glomerulonerphritis, and acute pancreatitis. Abnormal protease activity is suspected in development of liver thrombosis, pulmonary emphysema, atherosclerosis, and muscular dystrophy. Inactiviating disease-associated proteases by the administration of appropriate protease inhibitors has had limited success. Instead, one could use such proteases to target drugs to treat the condition. Protease mediated drug delivery offers such a possibility. Solubilizing groups are attached to insoluble drugs via a polypeptide chain which is specifically cleavable by certian proteases. When the solubilized drug enounters the protease, the solubilizing moieties are cleaved, and the drug precipitates at the disease location. Thus, a smaller systemic dosage could result in a therapeutic drug concentration at the treatment site with less systemic toxicity.

  16. Moving beyond traditional model calibration or how to better identify realistic model parameters: sub-period calibration

    NASA Astrophysics Data System (ADS)

    Gharari, S.; Hrachowitz, M.; Fenicia, F.; Savenije, H. H. G.

    2012-02-01

    Conceptual hydrological models often rely on calibration for the identification of their parameters. As these models are typically designed to reflect real catchment processes, a key objective of an appropriate calibration strategy is the determination of parameter sets that reflect a "realistic" model behavior. Previous studies have shown that parameter estimates for different calibration periods can be significantly different. This questions model transposability in time, which is one of the key conditions for the set-up of a "realistic" model. This paper presents a new approach that selects parameter sets that provide a consistent model performance in time. The approach consists of confronting model performance in different periods, and selecting parameter sets that are as close as possible to the optimum of each individual sub-period. While aiding model calibration, the approach is also useful as a diagnostic tool, illustrating tradeoffs in the identification of time consistent parameter sets. The approach is demonstrated in a case study where we illustrate the multi-objective calibration of the HyMod hydrological model to a Luxembourgish catchment.

  17. Patient-specific simulation of a trileaflet aortic heart valve in a realistic left ventricle and aorta

    NASA Astrophysics Data System (ADS)

    Gilmanov, Anvar; Le, Trung; Stolarski, Henryk; Sotiropoulos, Fotis

    2013-11-01

    We develop a patient-specific model of the left ventricle consisting of: (1) magnetic-resonance images (MRI) data for wall geometry and kinematics reconstruction of the left ventricle during one cardiac cycle and (2) an elastic trileaflet aortic heart valve implanted in (3) a realistic aorta interacting with blood flow driven by the pulsating left ventricle. Blood flow is simulated via a new fluid-structure interaction (FSI) method, which couples the sharp-interface CURVIB [L. Ge, F. Sotiropoulos, JCP, (2007)] for handling complex moving boundaries with a new, rotation-free finite-element (FE) formulation for simulating large tissue deformations [H. Stolarski, A. Gilmanov, F. Sotiropoulos, IJNME, (2013)] The new FE shell formulation has been extensively tested and validated for a range of relevant problems showing good agreements. Validation of the coupled FSI-FE-CURVIB model is carried out for a thin plate undergoing flow-induced vibrations in the wake of a square cylinder and the computed results are in good agreement with published data. The new approach has been applied to simulate dynamic interaction of a trileaflet aortic heart valve with pulsating blood flow at physiological conditions and realistic artery and left ventricle geometry.

  18. Effect of sliding friction on the dynamics of spur gear pair with realistic time-varying stiffness

    NASA Astrophysics Data System (ADS)

    He, Song; Gunda, Rajendra; Singh, Rajendra

    2007-04-01

    The chief objective of this article is to propose a new method of incorporating the sliding friction and realistic time-varying stiffness into an analytical (multi-degree-of-freedom) spur gear model and to evaluate their effects. An accurate finite element/contact mechanics analysis code is employed, in the "static" mode, to compute the mesh stiffness at every time instant under a range of loading conditions. Here, the time-varying stiffness is calculated as an effective function which may also include the effect of profile modifications. The realistic mesh stiffness is then incorporated into the linear time-varying spur gear model with the contributions of sliding friction. Proposed methods are illustrated via two spur gear examples and validated by using the finite element in the "dynamic" mode as experimental results. A key question whether the sliding friction is indeed the source of the off-line-of-action forces and motions is then answered by our analytical model. Finally, the effect of the profile modification on the dynamic transmission error has been analytically examined under the influence of sliding friction. For instance, the linear tip relief introduces an amplification in the off-line-of-action forces and motions due to an out of phase relationship between the normal load and friction forces.

  19. Gastroretentive delivery systems: hollow beads.

    PubMed

    Talukder, R; Fassihi, R

    2004-04-01

    The objective of this study was to develop a floatable multiparticulate system with potential for intragastric sustained drug delivery. Cross-linked beads were made by using calcium and low methoxylated pectin (LMP), which is an anionic polysaccharide, and calcium, LMP, and sodium alginate. Beads were dried separately in an air convection type oven at 40 degrees C for 6 hours and in a freeze dryer to evaluate the changes in bead characteristics due to process variability. Riboflavin (B-2), tetracycline (TCN), and Methotrexate (MTX) were used as model drugs for encapsulation. Ionic and nonionic excipients were added to study their effects on the release profiles of the beads. The presence of noncross linking agents in low amounts (less than 2%) did not significantly interfere with release kinetics. For an amphoteric drug like TCN, which has pH dependent solubility, three different pHs (1.5, 5.0, and 8.0) of cross-linking media were used to evaluate the effects of pH on the drug entrapment capacity of the beads. As anticipated, highest entrapment was possible when cross-linking media pH coincided with least drug solubility. Evaluation of the drying process demonstrated that the freeze-dried beads remained buoyant over 12 hours in United States Pharmacopeia (USP) hydrochloride buffer at pH 1.5, whereas the air-dried beads remained submerged throughout the release study. Confocal laser microscopy revealed the presence of air-filled hollow spaces inside the freeze dried beads, which was responsible for the flotation property of the beads. However, the release kinetics from freeze dried beads was independent of hydrodynamic conditions. Calcium-pectinate-alginate beads released their contents at much faster rates than did calcium-pectinate beads (100% in 10 hours vs. 50% in 10 hours). It appears that the nature of cross-linking, drying method, drug solubility, and production approach are all important and provide the opportunity and potential for development of a

  20. Multiday Fully Closed Loop Insulin Delivery in Monitored Outpatient Conditions

    ClinicalTrials.gov

    2014-04-29

    To Demonstrate That the Closed Loop System Can be Used Safely Over a Few Consecutive Days.; To Assess Effectiveness in Maintaining Patients' Glucose Levels in the Target Range of 70 to 180 mg/dl, Measured by Blood Glucose Sensor.; To Evaluate the User Experience With a Closed Loop System