Delay-based virtual congestion control in multi-tenant datacenters

NASA Astrophysics Data System (ADS)

Liu, Yuxin; Zhu, Danhong; Zhang, Dong

2018-03-01

With the evolution of cloud computing and virtualization, the congestion control of virtual datacenters has become the basic issue for multi-tenant datacenters transmission. Regarding to the friendly conflict of heterogeneous congestion control among multi-tenant, this paper proposes a delay-based virtual congestion control, which translates the multi-tenant heterogeneous congestion control into delay-based feedback uniformly by setting the hypervisor translation layer, modifying three-way handshake of explicit feedback and packet loss feedback and throttling receive window. The simulation results show that the delay-based virtual congestion control can effectively solve the unfairness of heterogeneous feedback congestion control algorithms.

Comparison of Gas Displacement based on Thermometry in the Pulse Tube with Rayleigh Scattering

NASA Astrophysics Data System (ADS)

Hagiwara, Yasumasa; Nara, Kenichi; Ito, Seitoku; Saito, Takamoto

A pulse tube refrigerator has high reliability because of its simple structure. Recently the level of development activity of the pulse tube refrigerator has increased, but the quantitative understanding of the refrigeration mechanism has not fully been obtained. Therefore various explanations were proposed. The concept of virtual gas piston in particular helps us to understand the function of a phase shifter such as a buffer tank and an orifice because the virtual gas piston corresponds to a piston of a Stirling refrigerator. However it is difficult to directly measure the averaged gas displacement which corresponds to the virtual gas piston because uniform gas flow such as a gas piston does not always exist. For example, there are a jet flow from orifice and circulated flows in a pulse tube, which are predicted theoretically. In spite of these phenomena, the averaged gas displacement is very important in practical use because it can simply predict the performance from the displacement. In this report, we calculate the averaged gas displacement and mass flow through an orifice. The mass flow is calculated from the pressure change in a buffer tank. The averaged gas displacement is calculated from temperature profiles in the pulse tube and the mass flow. It is necessary to measure temperature in the pulse tube as widely as possible in order to calculate the averaged gas displacement. We apply a method using the Rayleigh Scattering the thermometry in the pulse tube. With this method, it is possible to perform 2-dimensional measurement without disturbing the gas flow. By this method, the averaged gas displacements and the temperature profiles of basic and orifice types of refrigeration were compared.

Optimizing Virtual Network Functions Placement in Virtual Data Center Infrastructure Using Machine Learning

NASA Astrophysics Data System (ADS)

Bolodurina, I. P.; Parfenov, D. I.

2018-01-01

We have elaborated a neural network model of virtual network flow identification based on the statistical properties of flows circulating in the network of the data center and characteristics that describe the content of packets transmitted through network objects. This enabled us to establish the optimal set of attributes to identify virtual network functions. We have established an algorithm for optimizing the placement of virtual data functions using the data obtained in our research. Our approach uses a hybrid method of visualization using virtual machines and containers, which enables to reduce the infrastructure load and the response time in the network of the virtual data center. The algorithmic solution is based on neural networks, which enables to scale it at any number of the network function copies.

10 CFR Appendix D1 to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Clothes Dryers

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 3 2012-01-01 2012-01-01 false Uniform Test Method for Measuring the Energy Consumption... Appendix D1 to Subpart B of Part 430—Uniform Test Method for Measuring the Energy Consumption of Clothes... without heated or unheated forced air circulation to remove moisture from the clothing, remove wrinkles or...

10 CFR Appendix D2 to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Clothes Dryers

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 3 2014-01-01 2014-01-01 false Uniform Test Method for Measuring the Energy Consumption... Appendix D2 to Subpart B of Part 430—Uniform Test Method for Measuring the Energy Consumption of Clothes... forced air circulation to remove moisture from the clothing, remove wrinkles or prevent wrinkling of the...

10 CFR Appendix D1 to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Clothes Dryers

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 3 2013-01-01 2013-01-01 false Uniform Test Method for Measuring the Energy Consumption... Appendix D1 to Subpart B of Part 430—Uniform Test Method for Measuring the Energy Consumption of Clothes... without heated or unheated forced air circulation to remove moisture from the clothing, remove wrinkles or...

JIGSAW-GEO (1.0): Locally Orthogonal Staggered Unstructured Grid Generation for General Circulation Modelling on the Sphere

NASA Technical Reports Server (NTRS)

Engwirda, Darren

2017-01-01

An algorithm for the generation of non-uniform, locally orthogonal staggered unstructured spheroidal grids is described. This technique is designed to generate very high-quality staggered VoronoiDelaunay meshes appropriate for general circulation modelling on the sphere, including applications to atmospheric simulation, ocean-modelling and numerical weather prediction. Using a recently developed Frontal-Delaunay refinement technique, a method for the construction of high-quality unstructured spheroidal Delaunay triangulations is introduced. A locally orthogonal polygonal grid, derived from the associated Voronoi diagram, is computed as the staggered dual. It is shown that use of the Frontal-Delaunay refinement technique allows for the generation of very high-quality unstructured triangulations, satisfying a priori bounds on element size and shape. Grid quality is further improved through the application of hill-climbing-type optimisation techniques. Overall, the algorithm is shown to produce grids with very high element quality and smooth grading characteristics, while imposing relatively low computational expense. A selection of uniform and non-uniform spheroidal grids appropriate for high-resolution, multi-scale general circulation modelling are presented. These grids are shown to satisfy the geometric constraints associated with contemporary unstructured C-grid-type finite-volume models, including the Model for Prediction Across Scales (MPAS-O). The use of user-defined mesh-spacing functions to generate smoothly graded, non-uniform grids for multi-resolution-type studies is discussed in detail.

JIGSAW-GEO (1.0): locally orthogonal staggered unstructured grid generation for general circulation modelling on the sphere

NASA Astrophysics Data System (ADS)

Engwirda, Darren

2017-06-01

An algorithm for the generation of non-uniform, locally orthogonal staggered unstructured spheroidal grids is described. This technique is designed to generate very high-quality staggered Voronoi-Delaunay meshes appropriate for general circulation modelling on the sphere, including applications to atmospheric simulation, ocean-modelling and numerical weather prediction. Using a recently developed Frontal-Delaunay refinement technique, a method for the construction of high-quality unstructured spheroidal Delaunay triangulations is introduced. A locally orthogonal polygonal grid, derived from the associated Voronoi diagram, is computed as the staggered dual. It is shown that use of the Frontal-Delaunay refinement technique allows for the generation of very high-quality unstructured triangulations, satisfying a priori bounds on element size and shape. Grid quality is further improved through the application of hill-climbing-type optimisation techniques. Overall, the algorithm is shown to produce grids with very high element quality and smooth grading characteristics, while imposing relatively low computational expense. A selection of uniform and non-uniform spheroidal grids appropriate for high-resolution, multi-scale general circulation modelling are presented. These grids are shown to satisfy the geometric constraints associated with contemporary unstructured C-grid-type finite-volume models, including the Model for Prediction Across Scales (MPAS-O). The use of user-defined mesh-spacing functions to generate smoothly graded, non-uniform grids for multi-resolution-type studies is discussed in detail.

Pore-scale modeling of Capillary Penetration of Wetting Liquid into 3D Fibrous Media: A Critical Examination of Equivalent Capillary Concept

NASA Astrophysics Data System (ADS)

Palakurthi, Nikhil Kumar; Ghia, Urmila; Comer, Ken

2013-11-01

Capillary penetration of liquid through fibrous porous media is important in many applications such as printing, drug delivery patches, sanitary wipes, and performance fabrics. Historically, capillary transport (with a distinct liquid propagating front) in porous media is modeled using capillary-bundle theory. However, it is not clear if the capillary model (Washburn equation) describes the fluid transport in porous media accurately, as it assumes uniformity of pore sizes in the porous medium. The present work investigates the limitations of the applicability of the capillary model by studying liquid penetration through virtual fibrous media with uniform and non-uniform pore-sizes. For the non-uniform-pore fibrous medium, the effective capillary radius of the fibrous medium was estimated from the pore-size distribution curve. Liquid penetration into the 3D virtual fibrous medium at micro-scale was simulated using OpenFOAM, and the numerical results were compared with the Washburn-equation capillary-model predictions. Preliminary results show that the Washburn equation over-predicts the height rise in the early stages (purely inertial and visco-inertial stages) of capillary transport.

[Virtual reality simulation training in gynecology: review and perspectives].

PubMed

Ricard-Gauthier, Dominique; Popescu, Silvia; Benmohamed, Naida; Petignat, Patrick; Dubuisson, Jean

2016-10-26

Laparoscopic simulation has rapidly become an important tool for learning and acquiring technical skills in surgery. It is based on two different complementary pedagogic tools : the box model trainer and the virtual reality simulator. The virtual reality simulator has shown its efficiency by improving surgical skills, decreasing operating time, improving economy of movements and improving self-confidence. The main objective of this tool is the opportunity to easily organize a regular, structured and uniformed training program enabling an automated individualized feedback.

Portable oven air circulator

DOEpatents

Jorgensen, Jorgen A.; Nygren, Donald W.

1983-01-01

A portable air circulating apparatus for use in cooking ovens which is used to create air currents in the oven which transfer heat to cooking foodstuffs to promote more rapid and more uniform cooking or baking, the apparatus including a motor, fan blade and housing of metallic materials selected from a class of heat resistant materials.

Origin of the Valley Networks On Mars: A Hydrological Perspective

NASA Technical Reports Server (NTRS)

Gulick, Virginia C.

2000-01-01

The geomorphology of the Martian valley networks is examined from a hydrological perspective for their compatibility with an origin by rainfall, globally higher heat flow, and localized hydrothermal systems. Comparison of morphology and spatial distribution of valleys on geologic surfaces with terrestrial fluvial valleys suggests that most Martian valleys are probably not indicative of a rainfall origin, nor are they indicative of formation by an early global uniformly higher heat flow. In general, valleys are not uniformly distributed within geologic surface units as are terrestrial fluvial valleys. Valleys tend to form either as isolated systems or in clusters on a geologic surface unit leaving large expanses of the unit virtually untouched by erosion. With the exception of fluvial valleys on some volcanoes, most Martian valleys exhibit a sapping morphology and do not appear to have formed along with those that exhibit a runoff morphology. In contrast, terrestrial sapping valleys form from and along with runoff valleys. The isolated or clustered distribution of valleys suggests localized water sources were important in drainage development. Persistent ground-water outflow driven by localized, but vigorous hydrothermal circulation associated with magmatism, volcanism, impacts, or tectonism is, however, consistent with valley morphology and distribution. Snowfall from sublimating ice-covered lakes or seas may have provided an atmospheric water source for the formation of some valleys in regions where the surface is easily eroded and where localized geothermal/hydrothermal activity is sufficient to melt accumulated snowpacks.

Virtual-system-coupled adaptive umbrella sampling to compute free-energy landscape for flexible molecular docking.

PubMed

Higo, Junichi; Dasgupta, Bhaskar; Mashimo, Tadaaki; Kasahara, Kota; Fukunishi, Yoshifumi; Nakamura, Haruki

2015-07-30

A novel enhanced conformational sampling method, virtual-system-coupled adaptive umbrella sampling (V-AUS), was proposed to compute 300-K free-energy landscape for flexible molecular docking, where a virtual degrees of freedom was introduced to control the sampling. This degree of freedom interacts with the biomolecular system. V-AUS was applied to complex formation of two disordered amyloid-β (Aβ30-35 ) peptides in a periodic box filled by an explicit solvent. An interpeptide distance was defined as the reaction coordinate, along which sampling was enhanced. A uniform conformational distribution was obtained covering a wide interpeptide distance ranging from the bound to unbound states. The 300-K free-energy landscape was characterized by thermodynamically stable basins of antiparallel and parallel β-sheet complexes and some other complex forms. Helices were frequently observed, when the two peptides contacted loosely or fluctuated freely without interpeptide contacts. We observed that V-AUS converged to uniform distribution more effectively than conventional AUS sampling did. © 2015 Wiley Periodicals, Inc.

An integrated approach to patient-specific predictive modeling for single ventricle heart palliation.

PubMed

Corsini, Chiara; Baker, Catriona; Kung, Ethan; Schievano, Silvia; Arbia, Gregory; Baretta, Alessia; Biglino, Giovanni; Migliavacca, Francesco; Dubini, Gabriele; Pennati, Giancarlo; Marsden, Alison; Vignon-Clementel, Irene; Taylor, Andrew; Hsia, Tain-Yen; Dorfman, Adam

2014-01-01

In patients with congenital heart disease and a single ventricle (SV), ventricular support of the circulation is inadequate, and staged palliative surgery (usually 3 stages) is needed for treatment. In the various palliative surgical stages individual differences in the circulation are important and patient-specific surgical planning is ideal. In this study, an integrated approach between clinicians and engineers has been developed, based on patient-specific multi-scale models, and is here applied to predict stage 2 surgical outcomes. This approach involves four distinct steps: (1) collection of pre-operative clinical data from a patient presenting for SV palliation, (2) construction of the pre-operative model, (3) creation of feasible virtual surgical options which couple a three-dimensional model of the surgical anatomy with a lumped parameter model (LPM) of the remainder of the circulation and (4) performance of post-operative simulations to aid clinical decision making. The pre-operative model is described, agreeing well with clinical flow tracings and mean pressures. Two surgical options (bi-directional Glenn and hemi-Fontan operations) are virtually performed and coupled to the pre-operative LPM, with the hemodynamics of both options reported. Results are validated against postoperative clinical data. Ultimately, this work represents the first patient-specific predictive modeling of stage 2 palliation using virtual surgery and closed-loop multi-scale modeling.

Arctic storms simulated in atmospheric general circulation models under uniform high, uniform low, and variable resolutions

NASA Astrophysics Data System (ADS)

Roesler, E. L.; Bosler, P. A.; Taylor, M.

2016-12-01

The impact of strong extratropical storms on coastal communities is large, and the extent to which storms will change with a warming Arctic is unknown. Understanding storms in reanalysis and in climate models is important for future predictions. We know that the number of detected Arctic storms in reanalysis is sensitive to grid resolution. To understand Arctic storm sensitivity to resolution in climate models, we describe simulations designed to identify and compare Arctic storms at uniform low resolution (1 degree), at uniform high resolution (1/8 degree), and at variable resolution (1 degree to 1/8 degree). High-resolution simulations resolve more fine-scale structure and extremes, such as storms, in the atmosphere than a uniform low-resolution simulation. However, the computational cost of running a globally uniform high-resolution simulation is often prohibitive. The variable resolution tool in atmospheric general circulation models permits regional high-resolution solutions at a fraction of the computational cost. The storms are identified using the open-source search algorithm, Stride Search. The uniform high-resolution simulation has over 50% more storms than the uniform low-resolution and over 25% more storms than the variable resolution simulations. Storm statistics from each of the simulations is presented and compared with reanalysis. We propose variable resolution as a cost-effective means of investigating physics/dynamics coupling in the Arctic environment. Future work will include comparisons with observed storms to investigate tuning parameters for high resolution models. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2016-7402 A

Utilization of virtual learning environments in the allied health professions.

PubMed

Butina, Michelle; Brooks, Donna; Dominguez, Paul J; Mahon, Gwendolyn M

2013-01-01

Multiple technology based tools have been used to enhance skill development in allied health education, which now includes virtual learning environments. The purpose of this study was to explore whether, and how, this latest instructional technology is being adapted in allied health education. An online survey was circulated to all Association of Schools of Allied Health Professions (ASAHP) member institutions and focused on three broad areas of virtual learning environments: the uses of, the perceived pros and cons of, and the outcomes of utilizing them. Results show 40% (17 of 42) of the respondent use some form of the technology. The use of virtual learning technology in other healthcare professions (e.g., medicine) demonstrates the potential benefits to allied health education.

Innovative Culture, Part 2: Virtual Consultancies - Engaging Talent

DTIC Science & Technology

2016-01-21

Innovative Culture, Part II: Virtual Consultancies – Engaging Talent January 21, 2016 These are the final briefing slides as approved by...Engaging Talent (Innovative Culture, Part II) – Aims to facilitate and capitalize on the vast capacity for internal consultancy within the DoD...for talent with an industry model that values – and makes effective use of – young, fresh, innovative voices  With a huge uniformed workforce

Three-Dimensional (3D) Nanometrology Based on Scanning Electron Microscope (SEM) Stereophotogrammetry.

PubMed

Tondare, Vipin N; Villarrubia, John S; Vlada R, András E

2017-10-01

Three-dimensional (3D) reconstruction of a sample surface from scanning electron microscope (SEM) images taken at two perspectives has been known for decades. Nowadays, there exist several commercially available stereophotogrammetry software packages. For testing these software packages, in this study we used Monte Carlo simulated SEM images of virtual samples. A virtual sample is a model in a computer, and its true dimensions are known exactly, which is impossible for real SEM samples due to measurement uncertainty. The simulated SEM images can be used for algorithm testing, development, and validation. We tested two stereophotogrammetry software packages and compared their reconstructed 3D models with the known geometry of the virtual samples used to create the simulated SEM images. Both packages performed relatively well with simulated SEM images of a sample with a rough surface. However, in a sample containing nearly uniform and therefore low-contrast zones, the height reconstruction error was ≈46%. The present stereophotogrammetry software packages need further improvement before they can be used reliably with SEM images with uniform zones.

Radial particle-size segregation during packing of particulates into cylindrical containers

USGS Publications Warehouse

Ripple, C.D.; James, R.V.; Rubin, J.

1973-01-01

In a series of experiments, soil materials were placed in long cylindrical containers, using various packing procedures. Soil columns produced by deposition and simultaneous vibratory compaction were dense and axially uniform, but showed significant radial segregation of particle sizes. Similar results were obtained with deposition and simultaneous impact-type compaction when the impacts resulted in significant container "bouncing". The latter procedure, modified to minimize "bouncing" produced dense, uniform soil columns, showing little radial particle-size segregation. Other procedures tested (deposition alone and deposition followed by compaction) did not result in radial segregation, but produced columns showing either relatively low or axially nonuniform densities. Current data suggest that radial particle-size segregation is mainly due to vibration-induced particle circulation in which particles of various sizes have different circulation rates and paths. ?? 1973.

A selective laser sintering guide for transferring a virtual plan to real time surgery in composite mandibular reconstruction with free fibula osseous flaps.

PubMed

Leiggener, C; Messo, E; Thor, A; Zeilhofer, H-F; Hirsch, J-M

2009-02-01

The free fibular flap is the standard procedure for reconstructing mandibular defects. The graft has to be contoured to fit the defect so preoperative planning is required. The systems used previously do not allow transfer of the surgical plan to the operation room in an optimal way. The authors present a method to bring the virtual plan to real time surgery using a rapid prototyping guide. Planning was conducted using the Surgicase CMF software simulating surgery on a workstation. The osteotomies were translated into a rapid prototyping guide, sterilised and applied during surgery on the fibula allowing for the osteotomies and osteosynthesis to be performed with intact circulation. During reconstruction the authors were able to choose the best site for the osteotomies regarding circulation and as a result increased the precision and speed of treatment.

Sensitivity of Offshore Surface Fluxes and Sea Breezes to the Spatial Distribution of Sea-Surface Temperature

NASA Astrophysics Data System (ADS)

Lombardo, Kelly; Sinsky, Eric; Edson, James; Whitney, Michael M.; Jia, Yan

2018-03-01

A series of numerical sensitivity experiments is performed to quantify the impact of sea-surface temperature (SST) distribution on offshore surface fluxes and simulated sea-breeze dynamics. The SST simulations of two mid-latitude sea-breeze events over coastal New England are performed using a spatially-uniform SST, as well as spatially-varying SST datasets of 32- and 1-km horizontal resolutions. Offshore surface heat and buoyancy fluxes vary in response to the SST distribution. Local sea-breeze circulations are relatively insensitive, with minimal differences in vertical structure and propagation speed among the experiments. The largest thermal perturbations are confined to the lowest 10% of the sea-breeze column due to the relatively high stability of the mid-Atlantic marine atmospheric boundary layer (ABL) suppressing vertical mixing, resulting in the depth of the marine layer remaining unchanged. Minimal impacts on the column-averaged virtual potential temperature and sea-breeze depth translates to small changes in sea-breeze propagation speed. This indicates that the use of datasets with a fine-scale SST may not produce more accurate sea-breeze simulations in highly stable marine ABL regimes, though may prove more beneficial in less stable sub-tropical environments.

Diffuse fluorescence fiber probe for in vivo detection of circulating cells

NASA Astrophysics Data System (ADS)

Pera, Vivian; Tan, Xuefei; Runnels, Judith; Sardesai, Neha; Lin, Charles P.; Niedre, Mark

2017-03-01

There has been significant recent interest in the development of technologies for enumeration of rare circulating cells directly in the bloodstream in many areas of research, for example, in small animal models of circulating tumor cell dissemination during cancer metastasis. We describe a fiber-based optical probe that allows fluorescence detection of labeled circulating cells in vivo in a diffuse reflectance configuration. We validated this probe in a tissue-mimicking flow phantom model in vitro and in nude mice injected with fluorescently labeled multiple myeloma cells in vivo. Compared to our previous work, this design yields an improvement in detection signal-to-noise ratio of 10 dB, virtually eliminates problematic motion artifacts due to mouse breathing, and potentially allows operation in larger animals and limbs.

Wave field synthesis of moving virtual sound sources with complex radiation properties.

PubMed

Ahrens, Jens; Spors, Sascha

2011-11-01

An approach to the synthesis of moving virtual sound sources with complex radiation properties in wave field synthesis is presented. The approach exploits the fact that any stationary sound source of finite spatial extent radiates spherical waves at sufficient distance. The angular dependency of the radiation properties of the source under consideration is reflected by the amplitude and phase distribution on the spherical wave fronts. The sound field emitted by a uniformly moving monopole source is derived and the far-field radiation properties of the complex virtual source under consideration are incorporated in order to derive a closed-form expression for the loudspeaker driving signal. The results are illustrated via numerical simulations of the synthesis of the sound field of a sample moving complex virtual source.

Operation of a high impedance applied-B extraction ion diode on the SABRE positive polarity linear induction accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hanson, D.L.; Cuneo, M.E.; McKay, P.F.

We present results from initial experiments with a high impedance applied-B extraction diode on the SABRE ten stage linear induction accelerator (6.7 MV, 300 kA). We have demonstrated efficient coupling of power from the accelerator through an extended MITL (Magnetically Insulated Transmission Line) into a high intensity ion beam. Both MITL electron flow in the diode region and ion diode behavior, including ion source turn-on, virtual cathode formation and evolution, enhancement delay, and ion coupling efficiency, are strongly influenced by the geometry of the diode insulating magnetic field. For our present diode electrode geometry, electrons from the diode feed stronglymore » influence the evolution of the virtual cathode. Both experimental data and particle-in-cell numerical simulations show that uniform insulation of these feed electrons is required for uniform ion emission and efficient diode operation.« less

Building an Open-source Simulation Platform of Acoustic Radiation Force-based Breast Elastography

PubMed Central

Wang, Yu; Peng, Bo; Jiang, Jingfeng

2017-01-01

Ultrasound-based elastography including strain elastography (SE), acoustic radiation force Impulse (ARFI) imaging, point shear wave elastography (pSWE) and supersonic shear imaging (SSI) have been used to differentiate breast tumors among other clinical applications. The objective of this study is to extend a previously published virtual simulation platform built for ultrasound quasi-static breast elastography toward acoustic radiation force-based breast elastography. Consequently, the extended virtual breast elastography simulation platform can be used to validate image pixels with known underlying soft tissue properties (i.e. “ground truth”) in complex, heterogeneous media, enhancing confidence in elastographic image interpretations. The proposed virtual breast elastography system inherited four key components from the previously published virtual simulation platform: an ultrasound simulator (Field II), a mesh generator (Tetgen), a finite element solver (FEBio) and a visualization and data processing package (VTK). Using a simple message passing mechanism, functionalities have now been extended to acoustic radiation force-based elastography simulations. Examples involving three different numerical breast models with increasing complexity – one uniform model, one simple inclusion model and one virtual complex breast model derived from magnetic resonance imaging data, were used to demonstrate capabilities of this extended virtual platform. Overall, simulation results were compared with the published results. In the uniform model, the estimated shear wave speed (SWS) values were within 4% compared to the predetermined SWS values. In the simple inclusion and the complex breast models, SWS values of all hard inclusions in soft backgrounds were slightly underestimated, similar to what has been reported. The elastic contrast values and visual observation show that ARFI images have higher spatial resolution, while SSI images can provide higher inclusion-to-background contrast. In summary, our initial results were consistent with our expectations and what have been reported in the literature. The proposed (open-source) simulation platform can serve as a single gateway to perform many elastographic simulations in a transparent manner, thereby promoting collaborative developments. PMID:28075330

Building an open-source simulation platform of acoustic radiation force-based breast elastography

NASA Astrophysics Data System (ADS)

Wang, Yu; Peng, Bo; Jiang, Jingfeng

2017-03-01

Ultrasound-based elastography including strain elastography, acoustic radiation force impulse (ARFI) imaging, point shear wave elastography and supersonic shear imaging (SSI) have been used to differentiate breast tumors among other clinical applications. The objective of this study is to extend a previously published virtual simulation platform built for ultrasound quasi-static breast elastography toward acoustic radiation force-based breast elastography. Consequently, the extended virtual breast elastography simulation platform can be used to validate image pixels with known underlying soft tissue properties (i.e. ‘ground truth’) in complex, heterogeneous media, enhancing confidence in elastographic image interpretations. The proposed virtual breast elastography system inherited four key components from the previously published virtual simulation platform: an ultrasound simulator (Field II), a mesh generator (Tetgen), a finite element solver (FEBio) and a visualization and data processing package (VTK). Using a simple message passing mechanism, functionalities have now been extended to acoustic radiation force-based elastography simulations. Examples involving three different numerical breast models with increasing complexity—one uniform model, one simple inclusion model and one virtual complex breast model derived from magnetic resonance imaging data, were used to demonstrate capabilities of this extended virtual platform. Overall, simulation results were compared with the published results. In the uniform model, the estimated shear wave speed (SWS) values were within 4% compared to the predetermined SWS values. In the simple inclusion and the complex breast models, SWS values of all hard inclusions in soft backgrounds were slightly underestimated, similar to what has been reported. The elastic contrast values and visual observation show that ARFI images have higher spatial resolution, while SSI images can provide higher inclusion-to-background contrast. In summary, our initial results were consistent with our expectations and what have been reported in the literature. The proposed (open-source) simulation platform can serve as a single gateway to perform many elastographic simulations in a transparent manner, thereby promoting collaborative developments.

Applied virtual reality at the Research Triangle Institute

NASA Technical Reports Server (NTRS)

Montoya, R. Jorge

1994-01-01

Virtual Reality (VR) is a way for humans to use computers in visualizing, manipulating and interacting with large geometric data bases. This paper describes a VR infrastructure and its application to marketing, modeling, architectural walk through, and training problems. VR integration techniques used in these applications are based on a uniform approach which promotes portability and reusability of developed modules. For each problem, a 3D object data base is created using data captured by hand or electronically. The object's realism is enhanced through either procedural or photo textures. The virtual environment is created and populated with the data base using software tools which also support interactions with and immersivity in the environment. These capabilities are augmented by other sensory channels such as voice recognition, 3D sound, and tracking. Four applications are presented: a virtual furniture showroom, virtual reality models of the North Carolina Global TransPark, a walk through the Dresden Fraunenkirche, and the maintenance training simulator for the National Guard.

Can the Ocean's Heat Engine Control Horizontal Circulation? Insights From the Caspian Sea

NASA Astrophysics Data System (ADS)

Bruneau, Nicolas; Zika, Jan; Toumi, Ralf

2017-10-01

We investigate the role of the ocean's heat engine in setting horizontal circulation using a numerical model of the Caspian Sea. The Caspian Sea can be seen as a virtual laboratory—a compromise between realistic global models that are hampered by long equilibration times and idealized basin geometry models, which are not constrained by observations. We find that increases in vertical mixing drive stronger thermally direct overturning and consequent conversion of available potential to kinetic energy. Numerical solutions with water mass structures closest to observations overturn 0.02-0.04 × 106 m3/s (sverdrup) representing the first estimate of Caspian Sea overturning. Our results also suggest that the overturning is thermally forced increasing in intensity with increasing vertical diffusivity. Finally, stronger thermally direct overturning is associated with a stronger horizontal circulation in the Caspian Sea. This suggests that the ocean's heat engine can strongly impact broader horizontal circulations in the ocean.

Measurements of storm and nonstorm circulation in the northern Adriatic: October 2002 Through April 2003

USGS Publications Warehouse

Book, J.W.; Signell, R.P.; Perkins, H.

2007-01-01

Fifteen bottom-mounted Acoustic Doppler Current Profilers were deployed from October 2002 through April 2003 in the northern Adriatic Sea. Average transport from the portion of the Western Adriatic Current (WAC) along the Italian slope was 0.1470 ?? 0.0043 Sv, punctuated by bursts of more than twice that amount during storm events. Monthly means were calculated with times of strong wind-driven circulation excluded. These suggest a 2002/2003 seasonal separation consisting of October, December through February, and March through April. An extreme Po River flood influenced November conditions making seasonal categorization difficult. October generally had more kinetic energy and more vertical structure than other months, and near-inertial waves were more frequent in April and October. The Eastern Adriatic Current (EAC)/WAC (i.e. inflow/outflow) system was clearly present in the means for all months. The cyclonic gyre north of the Po River was present October through February. Generally, in the WAC, over 50% of kinetic energy came from vertically uniform monthly mean flows. Elsewhere, eddy kinetic energy was stronger than mean kinetic energy with 10-40% contributions for vertically uniform monthly mean flows, 40-60% for vertically uniform monthly varying flows, and 10-30% for vertically varying monthly varying flows. Mean currents for bora storms indicate enhancement of the EAC/WAC and the cyclonic northern gyre, a shift toward Kvarner Bay in EAC direction, a circulation null point south of the Po, and double-gyre bifurcation of flow at Istria. Strengthening of both the EAC and WAC also occurs during sirocco storms. Copyright 2007 by the American Geophysical Union.

Less-Costly Ion Implantation of Solar Cells

NASA Technical Reports Server (NTRS)

Fitzgerald, D. J.

1984-01-01

Experiments point way toward more relaxed controls over ion-implanation dosage and uniformity in solar-cell fabrication. Data indicate cell performance, measured by output current density at fixed voltage, virtually same whether implant is particular ion species or broad-beam mixture of several species.

Ubiquitous virtual private network: a solution for WSN seamless integration.

PubMed

Villa, David; Moya, Francisco; Villanueva, Félix Jesús; Aceña, Óscar; López, Juan Carlos

2014-01-06

Sensor networks are becoming an essential part of ubiquitous systems and applications. However, there are no well-defined protocols or mechanisms to access the sensor network from the enterprise information system. We consider this issue as a heterogeneous network interconnection problem, and as a result, the same concepts may be applied. Specifically, we propose the use of object-oriented middlewares to provide a virtual private network in which all involved elements (sensor nodes or computer applications) will be able to communicate as if all of them were in a single and uniform network.

Energy efficient LED layout optimization for near-uniform illumination

NASA Astrophysics Data System (ADS)

Ali, Ramy E.; Elgala, Hany

2016-09-01

In this paper, we consider the problem of designing energy efficient light emitting diodes (LEDs) layout while satisfying the illumination constraints. Towards this objective, we present a simple approach to the illumination design problem based on the concept of the virtual LED. We formulate a constrained optimization problem for minimizing the power consumption while maintaining a near-uniform illumination throughout the room. By solving the resulting constrained linear program, we obtain the number of required LEDs and the optimal output luminous intensities that achieve the desired illumination constraints.

An Intercomparison of the Dynamical Cores of Global Atmospheric Circulation Models for Mars

NASA Technical Reports Server (NTRS)

Hollingsworth, Jeffery L.; Bridger, Alison F. C.; Haberle, Robert M.

1998-01-01

This is a Final Report for a Joint Research Interchange (JRI) between NASA Ames Research Center and San Jose State University, Department of Meteorology. The focus of this JRI has been to evaluate the dynamical 'cores' of two global atmospheric circulation models for Mars that are in operation at the NASA Ames Research Center. The two global circulation models in use are fundamentally different: one uses spherical harmonics in its horizontal representation of field variables; the other uses finite differences on a uniform longitude-latitude grid. Several simulations have been conducted to assess how the dynamical processors of each of these circulation models perform using identical 'simple physics' parameterizations. A variety of climate statistics (e.g., time-mean flows and eddy fields) have been compared for realistic solstitial mean basic states. Results of this research have demonstrated that the two Mars circulation models with completely different spatial representations and discretizations produce rather similar circulation statistics for first-order meteorological fields, suggestive of a tendency for convergence of numerical solutions. Second and higher-order fields can, however, vary significantly between the two models.

An Intercomparison of the Dynamical Cores of Global Atmospheric Circulation Models for Mars

NASA Technical Reports Server (NTRS)

Hollingsworth, Jeffery L.; Bridger, Alison F. C.; Haberle, Robert M.

1998-01-01

This is a Final Report for a Joint Research Interchange (JRI) between NASA Ames Research Cen- ter and San Jose State University, Department of Meteorology. The focus of this JRI has been to evaluate the dynamical "cores" of two global atmospheric circulation models for Mars that are in operation at the NASA Ames Research Center. ne two global circulation models in use are fundamentally different: one uses spherical harmonics in its horizontal representation of field variables; the other uses finite differences on a uniform longitude-latitude grid. Several simulations have been conducted to assess how the dynamical processors of each of these circulation models perform using identical "simple physics" parameterizations. A variety of climate statistics (e.g., time-mean flows and eddy fields) have been compared for realistic solstitial mean basic states. Results of this research have demonstrated that the two Mars circulation models with completely different spatial representations and discretizations produce rather similar circulation statistics for first-order meteorological fields, suggestive of a tendency for convergence of numerical solutions. Second and higher-order fields can, however, vary significantly between the two models.

Studies of the field-of-view resolution tradeoff in virtual-reality systems

NASA Technical Reports Server (NTRS)

Piantanida, Thomas P.; Boman, Duane; Larimer, James; Gille, Jennifer; Reed, Charles

1992-01-01

Most virtual-reality systems use LCD-based displays that achieve a large field-of-view at the expense of resolution. A typical display will consist of approximately 86,000 pixels uniformly distributed over an 80-degree by 60-degree image. Thus, each pixel subtends about 13 minutes of arc at the retina; about the same as the resolvable features of the 20/200 line of a Snellen Eye Chart. The low resolution of LCD-based systems limits task performance in some applications. We have examined target-detection performance in a low-resolution virtual world. Our synthesized three-dimensional virtual worlds consisted of target objects that could be positioned at a fixed distance from the viewer, but at random azimuth and constrained elevation. A virtual world could be bounded by chromatic walls or by wire-frame, or it could be unbounded. Viewers scanned these worlds and indicated by appropriate gestures when they had detected the target object. By manipulating the viewer's field size and the chromatic and luminance contrast of annuli surrounding the field-of-view, we were able to assess the effect of field size on the detection of virtual objects in low-resolution synthetic worlds.

Interannual Variation of Surface Circulation in the Japan/East Sea due to External Forcings and Intrinsic Variability

NASA Astrophysics Data System (ADS)

Choi, Byoung-Ju; Cho, Seong Hun; Jung, Hee Seok; Lee, Sang-Ho; Byun, Do-Seong; Kwon, Kyungman

2018-03-01

The interannual variation of surface ocean currents can be as large as seasonal variation in the Japan/East Sea (JES). To identify the major factors that cause such interannual variability of surface ocean circulation in the JES, surface circulation was simulated from 1998 to 2009 using a three-dimensional model. Contributions of atmospheric forcing (ATM), open boundary data (OBC), and intrinsic variability (ITV) of the surface flow in the JES on the interannual variability of surface ocean circulation were separately examined using numerical simulations. Variability in surface circulation was quantified in terms of variance in sea surface height, 100-m depth water temperature, and surface currents. ITV was found to be the dominant factor that induced interannual variabilities of surface circulation, the main path of the East Korea Warm Current (EKWC), and surface kinetic energy on a time scale of 2-4 years. OBC and ATM were secondary factors contributing to the interannual variation of surface circulation. Interannual variation of ATM changed the separation latitude of EKWC and increased the variability of surface circulation in the Ulleung Basin. Interannual variation of OBC enhanced low-frequency changes in surface circulation and eddies in the Yamato Basin. It also modulated basin-wide uniform oscillations of sea level. This study suggests that precise estimation of initial conditions using data assimilation is essential for long-term prediction of surface circulation in the JES.

Ubiquitous Virtual Private Network: A Solution for WSN Seamless Integration

PubMed Central

Villa, David; Moya, Francisco; Villanueva, Félix Jesús; Aceña, Óscar; López, Juan Carlos

2014-01-01

Sensor networks are becoming an essential part of ubiquitous systems and applications. However, there are no well-defined protocols or mechanisms to access the sensor network from the enterprise information system. We consider this issue as a heterogeneous network interconnection problem, and as a result, the same concepts may be applied. Specifically, we propose the use of object-oriented middlewares to provide a virtual private network in which all involved elements (sensor nodes or computer applications) will be able to communicate as if all of them were in a single and uniform network. PMID:24399154

Uniform Interfaces for Distributed Systems.

DTIC Science & Technology

1980-05-01

in data str ’.ctures on stable storage (such as disk). The Virtual Terminals associated with a particular user (i.e., rM display terminal) are all...vec MESSAGESIZE let error = nil [S ReceiveAny (msg) // The copy is made so that lower-level routines may // munge the message template without losing

Review of influenza A virus in swine worldwide: a call for increased surveillance and research

USDA-ARS?s Scientific Manuscript database

Surveillance for influenza A viruses (IAV) circulating in pigs and other non-human mammals has been chronically underfunded and virtually nonexistent in many areas of the world. This deficit continues in spite of our knowledge that influenza is a disease shared between humans and pigs since at least...

Swine influenza - need for global surveillance and improved vaccines

USDA-ARS?s Scientific Manuscript database

Surveillance for influenza A viruses (IAV) circulating in pigs and other non-human mammals has been chronically underfunded and virtually nonexistent in many areas of the world. In March-April 2009, a novel pandemic H1N1 emerged and demonstrated in a very public forum the paucity of data on influenz...

Navigational strategies underlying phototaxis in larval zebrafish.

PubMed

Chen, Xiuye; Engert, Florian

2014-01-01

Understanding how the brain transforms sensory input into complex behavior is a fundamental question in systems neuroscience. Using larval zebrafish, we study the temporal component of phototaxis, which is defined as orientation decisions based on comparisons of light intensity at successive moments in time. We developed a novel "Virtual Circle" assay where whole-field illumination is abruptly turned off when the fish swims out of a virtually defined circular border, and turned on again when it returns into the circle. The animal receives no direct spatial cues and experiences only whole-field temporal light changes. Remarkably, the fish spends most of its time within the invisible virtual border. Behavioral analyses of swim bouts in relation to light transitions were used to develop four discrete temporal algorithms that transform the binary visual input (uniform light/uniform darkness) into the observed spatial behavior. In these algorithms, the turning angle is dependent on the behavioral history immediately preceding individual turning events. Computer simulations show that the algorithms recapture most of the swim statistics of real fish. We discovered that turning properties in larval zebrafish are distinctly modulated by temporal step functions in light intensity in combination with the specific motor history preceding these turns. Several aspects of the behavior suggest memory usage of up to 10 swim bouts (~10 sec). Thus, we show that a complex behavior like spatial navigation can emerge from a small number of relatively simple behavioral algorithms.

Parabiosis and single-cell RNA sequencing reveal a limited contribution of monocytes to myofibroblasts in kidney fibrosis.

PubMed

Kramann, Rafael; Machado, Flavia; Wu, Haojia; Kusaba, Tetsuro; Hoeft, Konrad; Schneider, Rebekka K; Humphreys, Benjamin D

2018-05-03

Fibrosis is the common final pathway of virtually all chronic injury to the kidney. While it is well accepted that myofibroblasts are the scar-producing cells in the kidney, their cellular origin is still hotly debated. The relative contribution of proximal tubular epithelium and circulating cells, including mesenchymal stem cells, macrophages, and fibrocytes, to the myofibroblast pool remains highly controversial. Using inducible genetic fate tracing of proximal tubular epithelium, we confirm that the proximal tubule does not contribute to the myofibroblast pool. However, in parabiosis models in which one parabiont is genetically labeled and the other is unlabeled and undergoes kidney fibrosis, we demonstrate that a small fraction of genetically labeled renal myofibroblasts derive from the circulation. Single-cell RNA sequencing confirms this finding but indicates that these cells are circulating monocytes, express few extracellular matrix or other myofibroblast genes, and express many proinflammatory cytokines. We conclude that this small circulating myofibroblast progenitor population contributes to renal fibrosis by paracrine rather than direct mechanisms.

Multi-Resolution Unstructured Grid-Generation for Geophysical Applications on the Sphere

NASA Technical Reports Server (NTRS)

Engwirda, Darren

2015-01-01

An algorithm for the generation of non-uniform unstructured grids on ellipsoidal geometries is described. This technique is designed to generate high quality triangular and polygonal meshes appropriate for general circulation modelling on the sphere, including applications to atmospheric and ocean simulation, and numerical weather predication. Using a recently developed Frontal-Delaunay-refinement technique, a method for the construction of high-quality unstructured ellipsoidal Delaunay triangulations is introduced. A dual polygonal grid, derived from the associated Voronoi diagram, is also optionally generated as a by-product. Compared to existing techniques, it is shown that the Frontal-Delaunay approach typically produces grids with near-optimal element quality and smooth grading characteristics, while imposing relatively low computational expense. Initial results are presented for a selection of uniform and non-uniform ellipsoidal grids appropriate for large-scale geophysical applications. The use of user-defined mesh-sizing functions to generate smoothly graded, non-uniform grids is discussed.

Beamforming strategy of ULA and UCA sensor configuration in multistatic passive radar

NASA Astrophysics Data System (ADS)

Hossa, Robert

2009-06-01

A Beamforming Network (BN) concept of Uniform Linear Array (ULA) and Uniform Circular Array (UCA) dipole configuration designed to multistatic passive radar is considered in details. In the case of UCA configuration, computationally efficient procedure of beamspace transformation from UCA to virtual ULA configuration with omnidirectional coverage is utilized. If effect, the idea of the proposed solution is equivalent to the techniques of antenna array factor shaping dedicated to ULA structure. Finally, exemplary results from the computer software simulations of elaborated spatial filtering solutions to reference and surveillance channels are provided and discussed.

Effects of parasagittal meningiomas on intracranial venous circulation assessed by the virtual reality technology.

PubMed

Wang, Shousen; Ying, Jianbin; Wei, Liangfeng; Li, Shiqing; Jing, Junjie

2015-01-01

This study is to investigate the compensatory intracranial venous pathways in parasagittal meningiomas (PSM) patients by virtual reality technology. A total of 48 PSM patients (tumor group) and 20 patients with trigeminal neuralgia and hemifacial spasm but without intracranial venous diseases (control group) were enrolled. All patients underwent 3D CE-MRV examination. The 3D reconstructed images by virtual reality technology were used for assessment of diameter and number of intracranial veins, tumor location, venous sinus invasion degree and collateral circulation formation. Diameter of bridging veins in posterior 1/3 superior sagittal sinus (SSS) in tumor group was significantly smaller than that of the control group (P < 0.05). For tumors located in mid 1/3 SSS, diameter of bridging veins and vein of Labbé (VL) in posterior 1/3 SSS decreased significantly (P < 0.05). For tumors located in posterior 1/3 SSS, bridging vein number and transverse sinus (TS) diameter significantly decreased while superficial Sylvian vein (SSV) diameter increased significantly (P < 0.05). Compared with tumor in posterior 1/3 SSS subgroup, number of bridging veins in the tumor in mid 1/3 SSS subgroup increased significantly (P < 0.05). Compared with control group, only the bridging vein number in anterior 1/3 SSS segment in invasion Type 3-4 tumor subgroup decreased significantly (P < 0.05). Diameter of TS and bridging veins in posterior 1/3 SSS segment in sinus invasion Type 5-6 tumor subgroup decreased significantly (P < 0.05). Compared with control group, only the diameter of VL and TS of collateral circulation Grade 1 tumor subgroup decreased significantly (P < 0.05) while in Grade 3 tumor subgroup, TS diameter decreased and SSV diameter increased significantly (P < 0.05). The intracranial blood flow is mainly drained through SSV drainage after SSS occlusion by PSM.

Effects of parasagittal meningiomas on intracranial venous circulation assessed by the virtual reality technology

PubMed Central

Wang, Shousen; Ying, Jianbin; Wei, Liangfeng; Li, Shiqing; Jing, Junjie

2015-01-01

Objective: This study is to investigate the compensatory intracranial venous pathways in parasagittal meningiomas (PSM) patients by virtual reality technology. Methods: A total of 48 PSM patients (tumor group) and 20 patients with trigeminal neuralgia and hemifacial spasm but without intracranial venous diseases (control group) were enrolled. All patients underwent 3D CE-MRV examination. The 3D reconstructed images by virtual reality technology were used for assessment of diameter and number of intracranial veins, tumor location, venous sinus invasion degree and collateral circulation formation. Results: Diameter of bridging veins in posterior 1/3 superior sagittal sinus (SSS) in tumor group was significantly smaller than that of the control group (P < 0.05). For tumors located in mid 1/3 SSS, diameter of bridging veins and vein of Labbé (VL) in posterior 1/3 SSS decreased significantly (P < 0.05). For tumors located in posterior 1/3 SSS, bridging vein number and transverse sinus (TS) diameter significantly decreased while superficial Sylvian vein (SSV) diameter increased significantly (P < 0.05). Compared with tumor in posterior 1/3 SSS subgroup, number of bridging veins in the tumor in mid 1/3 SSS subgroup increased significantly (P < 0.05). Compared with control group, only the bridging vein number in anterior 1/3 SSS segment in invasion Type 3-4 tumor subgroup decreased significantly (P < 0.05). Diameter of TS and bridging veins in posterior 1/3 SSS segment in sinus invasion Type 5-6 tumor subgroup decreased significantly (P < 0.05). Compared with control group, only the diameter of VL and TS of collateral circulation Grade 1 tumor subgroup decreased significantly (P < 0.05) while in Grade 3 tumor subgroup, TS diameter decreased and SSV diameter increased significantly (P < 0.05). Conclusions: The intracranial blood flow is mainly drained through SSV drainage after SSS occlusion by PSM. PMID:26550184

On the quasi-steady aerodynamics of normal hovering flight part I: the induced power factor

PubMed Central

Nabawy, Mostafa R. A.; Crowther, William J.

2014-01-01

An analytical treatment to quantify the losses captured in the induced power factor, k, is provided for flapping wings in normal hover, including the effects of non-uniform downwash, tip losses and finite flapping amplitude. The method is based on a novel combination of actuator disc and lifting line blade theories that also takes into account the effect of advance ratio. The model has been evaluated against experimental results from the literature and qualitative agreement obtained for the effect of advance ratio on the lift coefficient of revolving wings. Comparison with quantitative experimental data for the circulation as a function of span for a fruitfly wing shows that the model is able to correctly predict the circulation shape of variation, including both the magnitude of the peak circulation and the rate of decay in circulation towards zero. An evaluation of the contributions to induced power factor in normal hover for eight insects is provided. It is also shown how Reynolds number can be accounted for in the induced power factor, and good agreement is obtained between predicted span efficiency as a function of Reynolds number and numerical results from the literature. Lastly, it is shown that for a flapping wing in hover k owing to the non-uniform downwash effect can be reduced to 1.02 using an arcsech chord distribution. For morphologically realistic wing shapes based on beta distributions, it is shown that a value of 1.07 can be achieved for a radius of first moment of wing area at 40% of wing length. PMID:24522785

On the quasi-steady aerodynamics of normal hovering flight part I: the induced power factor.

PubMed

Nabawy, Mostafa R A; Crowther, William J

2014-04-06

An analytical treatment to quantify the losses captured in the induced power factor, k, is provided for flapping wings in normal hover, including the effects of non-uniform downwash, tip losses and finite flapping amplitude. The method is based on a novel combination of actuator disc and lifting line blade theories that also takes into account the effect of advance ratio. The model has been evaluated against experimental results from the literature and qualitative agreement obtained for the effect of advance ratio on the lift coefficient of revolving wings. Comparison with quantitative experimental data for the circulation as a function of span for a fruitfly wing shows that the model is able to correctly predict the circulation shape of variation, including both the magnitude of the peak circulation and the rate of decay in circulation towards zero. An evaluation of the contributions to induced power factor in normal hover for eight insects is provided. It is also shown how Reynolds number can be accounted for in the induced power factor, and good agreement is obtained between predicted span efficiency as a function of Reynolds number and numerical results from the literature. Lastly, it is shown that for a flapping wing in hover k owing to the non-uniform downwash effect can be reduced to 1.02 using an arcsech chord distribution. For morphologically realistic wing shapes based on beta distributions, it is shown that a value of 1.07 can be achieved for a radius of first moment of wing area at 40% of wing length.

Virtual population-based assessment of the impact of 3 Tesla radiofrequency shimming and thermoregulation on safety and B1 + uniformity.

PubMed

Murbach, Manuel; Neufeld, Esra; Cabot, Eugenia; Zastrow, Earl; Córcoles, Juan; Kainz, Wolfgang; Kuster, Niels

2016-09-01

To assess the effect of radiofrequency (RF) shimming of a 3 Tesla (T) two-port body coil on B1 + uniformity, the local specific absorption rate (SAR), and the local temperature increase as a function of the thermoregulatory response. RF shimming alters induced current distribution, which may result in large changes in the level and location of absorbed RF energy. We investigated this effect with six anatomical human models from the Virtual Population in 10 imaging landmarks and four RF coils. Three thermoregulation models were applied to estimate potential local temperature increases, including a newly proposed model for impaired thermoregulation. Two-port RF shimming, compared to circular polarization mode, can increase the B1 + uniformity on average by +32%. Worst-case SAR excitations increase the local RF power deposition on average by +39%. In the first level controlled operating mode, induced peak temperatures reach 42.5°C and 45.6°C in patients with normal and impaired thermoregulation, respectively. Image quality with 3T body coils can be significantly increased by RF shimming. Exposure in realistic scan scenarios within guideline limits can be considered safe for a broad patient population with normal thermoregulation. Patients with impaired thermoregulation should not be scanned outside of the normal operating mode. Magn Reson Med 76:986-997, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Virtual seminars

NASA Astrophysics Data System (ADS)

Nelson, H. Roice

1997-06-01

A virtual seminar (SM) is an economic and effective instructional tool for teaching students who are at a distance from their instructor. Like conventional class room teaching, a virtual seminar requires an instructor, a student, and a method of communication. Teleconferencing, video conferencing, intranets and the Internet give learners in a Virtual Seminar the ability to interact immediately with their mentors and receive real and relevant answers. This paper shows how industry and academia can benefit from using methods developed and experience gained in presenting the first virtual seminars to academic and petroleum industry participants in mid-1996. The information explosion in industry means that business or technical information is worthless until it is assimilated into a corporate knowledge management system. A search for specific information often turns into a filtering exercise or an attempt to find patterns and classify retrieved material. In the setting of an interactive corporate information system, virtual seminars meet the need for a productive new relationship between creative people and the flux of corporate knowledge. Experience shows that it is more efficient to circulate timesensitive and confidential information electronically through a virtual seminar. Automating the classification of information and removing that task from the usual work load creates an electronic corporate memory and enhances the value of the knowledge to both users and a corporation. Catalogued benchmarks, best-practice standards, and Knowledge Maps (SM) of experience serve as key aids to communicating knowledge through virtual seminars and converting that knowledge into a profit-making asset.

Heat balance statistics derived from four-dimensional assimilations with a global circulation model

NASA Technical Reports Server (NTRS)

Schubert, S. D.; Herman, G. F.

1981-01-01

The reported investigation was conducted to develop a reliable procedure for obtaining the diabatic and vertical terms required for atmospheric heat balance studies. The method developed employs a four-dimensional assimilation mode in connection with the general circulation model of NASA's Goddard Laboratory for Atmospheric Sciences. The initial analysis was conducted with data obtained in connection with the 1976 Data Systems Test. On the basis of the results of the investigation, it appears possible to use the model's observationally constrained diagnostics to provide estimates of the global distribution of virtually all of the quantities which are needed to compute the atmosphere's heat and energy balance.

Origin and Radiative Forcing of Black Carbon Aerosol: Production and Consumption Perspectives.

PubMed

Meng, Jing; Liu, Junfeng; Yi, Kan; Yang, Haozhe; Guan, Dabo; Liu, Zhu; Zhang, Jiachen; Ou, Jiamin; Dorling, Stephen; Mi, Zhifu; Shen, Huizhong; Zhong, Qirui; Tao, Shu

2018-05-14

Air pollution, a threat to air quality and human health, has attracted ever-increasing attention in recent years. In addition to having local influence, air pollutants can also travel the globe via atmospheric circulation and international trade. Black carbon (BC), emitted from incomplete combustion, is a unique but representative particulate pollutant. This study tracked down the BC aerosol and its direct radiative forcing to the emission sources and final consumers using the global chemical transport model (MOZART-4), the rapid radiative transfer model for general circulation simulations (RRTM), and a multiregional input-output analysis (MRIO). BC was physically transported (i.e., atmospheric transport) from western to eastern countries in the midlatitude westerlies, but its magnitude is near an order of magnitude higher if the virtual flow embodied in international trade is considered. The transboundary effects on East and South Asia by other regions increased from about 3% (physical transport only) to 10% when considering both physical and virtual transport. The influence efficiency on East Asia was also large because of the comparatively large emission intensity and emission-intensive exports (e.g., machinery and equipment). The radiative forcing in Africa imposed by consumption from Europe, North America, and East Asia (0.01 Wm -2 ) was even larger than the total forcing in North America. Understanding the supply chain and incorporating both atmospheric and virtual transport may improve multilateral cooperation on air pollutant mitigation both domestically and internationally.

Global coordination for swine influenza virus surveillance and research: what are we missing from the big picture?

USDA-ARS?s Scientific Manuscript database

Introduction Surveillance for influenza A viruses (IAV) circulating in pigs and other non-human mammals has been chronically underfunded and virtually nonexistent in many areas of the world. This deficit continues in spite of our knowledge that influenza is a disease shared between man and pig fro...

7 CFR 58.622 - Hardening and storage rooms.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Hardening and storage rooms. 58.622 Section 58.622....622 Hardening and storage rooms. Hardening and storage rooms for frozen desserts shall be constructed... insure adequate storage temperature (−10° or lower). Air shall be circulated to maintain uniform...

7 CFR 58.622 - Hardening and storage rooms.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Hardening and storage rooms. 58.622 Section 58.622....622 Hardening and storage rooms. Hardening and storage rooms for frozen desserts shall be constructed... insure adequate storage temperature (−10° or lower). Air shall be circulated to maintain uniform...

7 CFR 58.622 - Hardening and storage rooms.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Hardening and storage rooms. 58.622 Section 58.622....622 Hardening and storage rooms. Hardening and storage rooms for frozen desserts shall be constructed... insure adequate storage temperature (−10° or lower). Air shall be circulated to maintain uniform...

Development of a robotic evaluation system for the ability of proprioceptive sensation in slow hand motion.

PubMed

Tanaka, Yoshiyuki; Mizoe, Genki; Kawaguchi, Tomohiro

2015-01-01

This paper proposes a simple diagnostic methodology for checking the ability of proprioceptive/kinesthetic sensation by using a robotic device. The perception ability of virtual frictional forces is examined in operations of the robotic device by the hand at a uniform slow velocity along the virtual straight/circular path. Experimental results by healthy subjects demonstrate that percentage of correct answers for the designed perceptual tests changes in the motion direction as well as the arm configuration and the HFM (human force manipulability) measure. It can be supposed that the proposed methodology can be applied into the early detection of neuromuscular/neurological disorders.

Affective outcomes of virtual reality exposure therapy for anxiety and specific phobias: a meta-analysis.

PubMed

Parsons, Thomas D; Rizzo, Albert A

2008-09-01

Virtual reality exposure therapy (VRET) is an increasingly common treatment for anxiety and specific phobias. Lacking is a quantitative meta-analysis that enhances understanding of the variability and clinical significance of anxiety reduction outcomes after VRET. Searches of electronic databases yielded 52 studies, and of these, 21 studies (300 subjects) met inclusion criteria. Although meta-analysis revealed large declines in anxiety symptoms following VRET, moderator analyses were limited due to inconsistent reporting in the VRET literature. This highlights the need for future research studies that report uniform and detailed information regarding presence, immersion, anxiety and/or phobia duration, and demographics.

Regular expansion solutions for small Peclet number heat or mass transfer in concentrated two-phase particulate systems

NASA Technical Reports Server (NTRS)

Yaron, I.

1974-01-01

Steady state heat or mass transfer in concentrated ensembles of drops, bubbles or solid spheres in uniform, slow viscous motion, is investigated. Convective effects at small Peclet numbers are taken into account by expanding the nondimensional temperature or concentration in powers of the Peclet number. Uniformly valid solutions are obtained, which reflect the effects of dispersed phase content and rate of internal circulation within the fluid particles. The dependence of the range of Peclet and Reynolds numbers, for which regular expansions are valid, on particle concentration is discussed.

Ecological network analysis on global virtual water trade.

PubMed

Yang, Zhifeng; Mao, Xufeng; Zhao, Xu; Chen, Bin

2012-02-07

Global water interdependencies are likely to increase with growing virtual water trade. To address the issues of the indirect effects of water trade through the global economic circulation, we use ecological network analysis (ENA) to shed insight into the complicated system interactions. A global model of virtual water flow among agriculture and livestock production trade in 1995-1999 is also built as the basis for network analysis. Control analysis is used to identify the quantitative control or dependency relations. The utility analysis provides more indicators for describing the mutual relationship between two regions/countries by imitating the interactions in the ecosystem and distinguishes the beneficiary and the contributor of virtual water trade system. Results show control and utility relations can well depict the mutual relation in trade system, and direct observable relations differ from integral ones with indirect interactions considered. This paper offers a new way to depict the interrelations between trade components and can serve as a meaningful start as we continue to use ENA in providing more valuable implications for freshwater study on a global scale.

Recent intensification of the Walker Circulation and the role of natural sea surface temperature variability

NASA Astrophysics Data System (ADS)

Zhao, X.; Allen, R.

2017-12-01

In a warming world, the tropical atmospheric overturning circulation-including the Walker Circulation-is expected to weaken due to thermodynamic constraints. Tropical precipitation increases at a slower rate than water vapor-which increases according to Clausius Clapeyron scaling, assuming constant relative humidity-so the tropical overturning circulation slows down. This is supported by both observations and model simulations, which show a slowdown of the Walker Circulation over the 20th century. Model projections suggest a further weakening of the Walker Circulation in the 21st century. However, over the last several decades (1979-2014), multiple observations reveal a robust strengthening of the Walker Circulation. Although coupled CMIP5 simulations are unable to reproduce this strengthening, AMIP simulations-which feature the observed evolution of SSTs-are generally able to reproduce it. Assuming the ensemble mean sea surface temperatures (SSTs) from historical CMIP5 simulations accurately represent the externally forced SST response, the observed SSTs can be decomposed into a forced and an unforced component. CAM5 AMIP-type simulations driven by the unforced component of observed SSTs reproduce the observed strengthening of the Walker Circulation. Corresponding simulations driven by the forced component of observed SSTs yield a weaker Walker Circulation. These results are consistent with the zonal tropical SST gradient and the Bjerknes feedback. The unforced component of SSTs yield an increased SST gradient over tropical Pacific (a La Nina like pattern) and strengthening of the tropical trade winds, which constitute the lower branch of the Walker Circulation. The forced component of SSTs yields a zonally uniform tropical Pacific SST warming and a marginal weakening of the Walker Circulation. Our results suggest significant modulation of the tropical Walker Circulation by natural SST variability over the last several decades.

Navigational strategies underlying phototaxis in larval zebrafish

PubMed Central

Chen, Xiuye; Engert, Florian

2014-01-01

Understanding how the brain transforms sensory input into complex behavior is a fundamental question in systems neuroscience. Using larval zebrafish, we study the temporal component of phototaxis, which is defined as orientation decisions based on comparisons of light intensity at successive moments in time. We developed a novel “Virtual Circle” assay where whole-field illumination is abruptly turned off when the fish swims out of a virtually defined circular border, and turned on again when it returns into the circle. The animal receives no direct spatial cues and experiences only whole-field temporal light changes. Remarkably, the fish spends most of its time within the invisible virtual border. Behavioral analyses of swim bouts in relation to light transitions were used to develop four discrete temporal algorithms that transform the binary visual input (uniform light/uniform darkness) into the observed spatial behavior. In these algorithms, the turning angle is dependent on the behavioral history immediately preceding individual turning events. Computer simulations show that the algorithms recapture most of the swim statistics of real fish. We discovered that turning properties in larval zebrafish are distinctly modulated by temporal step functions in light intensity in combination with the specific motor history preceding these turns. Several aspects of the behavior suggest memory usage of up to 10 swim bouts (~10 sec). Thus, we show that a complex behavior like spatial navigation can emerge from a small number of relatively simple behavioral algorithms. PMID:24723859

Sun-stirred Kraken Mare: Circulation in Titan's seas induced by solar heating and methane precipitation

NASA Astrophysics Data System (ADS)

Tokano, Tetsuya; Lorenz, Ralph D.

2016-05-01

Density-driven circulation in Titan's seas forced by solar heating and methane evaporation/precipitation is simulated by an ocean circulation model. If the sea is transparent to sunlight, solar heating can induce anti-clockwise gyres near the sea surface and clockwise gyres near the sea bottom. The gyres are in geostrophic balance between the radially symmetric pressure gradient force and Coriolis force. If instead the sea is turbid and most sunlight is absorbed near the sea surface, the sea gets stratified in warm seasons and the circulation remains weak. Precipitation causes compositional stratification of the sea to an extent that the sea surface temperature can be lower than the sea interior temperature without causing a convective overturning. Non-uniform precipitation can also generate a latitudinal gradient in the methane mole fraction and density, which drives a meridional overturning with equatorward currents near the sea surface and poleward currents near the sea bottom. However, gyres are more ubiquitous than meridional overturning.

Dynamics of Cross-Shore Thermal Exchange Over Nonuniform Bathymetry

NASA Astrophysics Data System (ADS)

Safaie, A.; Davis, K. A.; Pawlak, G. R.

2016-02-01

The hydrodynamics of cross-shelf circulation on the inner shelf influence coastal ecosystems through the transport of heat, salt, nutrients, and planktonic organisms. While cross-shelf exchange on wide continental shelves has received a fair amount of attention in literature, the mechanisms for cross-shelf exchange on narrow shelves with steep, rough, and highly irregular bathymetry, characteristic of coral reef shorelines, is not well understood. Previous observational studies from reefs at Eilat, Israel and Oahu, Hawaii, have demonstrated the importance of surface heat flux in driving cross-shore transport. While both sites experienced offshore surface flow during daytime warming periods and offshore flow near the bed during nighttime cooling, the phase differences between the surface heat fluxes and thermal responses at the two sites indicate different dynamic flow regimes based on momentum and thermal balances. This study examines the dynamical structure of thermally driven flows using numerical modeling to investigate the hypothesis that thermally driven baroclinic exchange is important to cross-shore circulation for tropical coastlines. We use the open-source Regional Ocean Modeling System (ROMS), a free-surface, three-dimensional circulation model, considering a simple wedge case with uniform bathymetry in the alongshore direction, and heat flux applied uniformly to the surface. We examine different flow regimes using scaling of the momentum and thermal balance equations. We also explore the parameter space for the momentum balance describing cross-shore thermal exchange, and thoroughly characterize the exchange structure by investigating the dominant forcing regimes, the mechanisms responsible for modulating thermal circulation, and the effects of temporal variations in vertical mixing and heating/cooling buoyancy flux. Results are compared against existing data sets to evaluate the ability of the model to represent these flows.

The Variable Importance of General Intelligence ("g") in the Cognitive Abilities of Children and Adolescents

ERIC Educational Resources Information Center

Kane, Harrison D.; Brand, Christopher R.

2006-01-01

Virtually all research affirms the importance of a general factor (i.e., Spearman's "g") in accounting for individual differences in intelligence (Spearman, 1904). However, some scholars have suggested that cognitive abilities are not organised uniformly across all levels of age and ability. Using standardisation data from the Woodcock Johnson…

Flow characteristics of bounded self-organized dust vortex in a complex plasma

NASA Astrophysics Data System (ADS)

Laishram, Modhuchandra; Sharma, D.; Chattopdhyay, P. K.; Kaw, P. K.

2018-01-01

Dust clouds are often formed in many dusty plasma experiments, when micron size dust particles introduced in the plasma are confined by spatial non-uniformities of the potential. These formations show self-organized patterns like vortex or circulation flows. Steady-state equilibrium dynamics of such dust clouds is analyzed by 2D hydrodynamics for varying Reynolds number, Re, when the cloud is confined in an azimuthally symmetric cylindrical setup by an effective potential and is in a dynamic equilibrium with an unbounded sheared plasma flow. The nonconservative forcing due to ion flow shear generates finite vorticity in the confined dust clouds. In the linear limit (Re ≪ 1), the collective flow is characterized by a single symmetric and elongated vortex with scales correlating with the driving field and those generated by friction with the boundaries. However in the high Re limit, (Re ≥ 1), the nonlinear inertial transport (u . ∇u) is effective and the vortex structure is characterized by an asymmetric equilibrium and emergence of a circular core region with uniform vorticity, over which the viscous stress is negligible. The core domain is surrounded by a virtual boundary of highly convective flow followed by thin shear layers filled with low-velocity co- and counter-rotating vortices, enabling the smooth matching with external boundary conditions. In linear regime, the effective boundary layer thickness is recovered to scale with the dust kinematic viscosity as Δr ≈ μ1/3 and is modified as Δr ≈ (μL∥/u)1/2 in the nonlinear regime through a critical kinematic viscosity μ∗ that signifies a structural bifurcation of the flow field solutions. The flow characteristics recovered are relevant to many microscopic biological processes at lower Re, as well as gigantic vortex flows such as Jovian great red spot and white ovals at higher Re.

Tropical Cyclone Ensemble Data Assimilation

DTIC Science & Technology

2012-09-30

the global system. The improvement is almost uniform in the extratropics , while in the tropics clear improvements tend to occur in the immediate...surrounding of storms . The latter result suggests that the limited area analysis provides a better representation of the interactions between the...circulation of the storm and the wind field in its immediate vicinity. 2

Infant formula feeding increases hepatic cholesterol 7 alpha hydroxylase (CYP7A1) expression and fecal bile acid loss in neonatal piglets

USDA-ARS?s Scientific Manuscript database

During the postnatal feeding period, formula-fed infants have higher cholesterol synthesis rates, and lower circulating cholesterol concentrations as compared to their breastfed counterparts. Although this disparity has been attributed to the uniformly low dietary cholesterol content of typical inf...

A computational model-based validation of Guyton's analysis of cardiac output and venous return curves

NASA Technical Reports Server (NTRS)

Mukkamala, R.; Cohen, R. J.; Mark, R. G.

2002-01-01

Guyton developed a popular approach for understanding the factors responsible for cardiac output (CO) regulation in which 1) the heart-lung unit and systemic circulation are independently characterized via CO and venous return (VR) curves, and 2) average CO and right atrial pressure (RAP) of the intact circulation are predicted by graphically intersecting the curves. However, this approach is virtually impossible to verify experimentally. We theoretically evaluated the approach with respect to a nonlinear, computational model of the pulsatile heart and circulation. We developed two sets of open circulation models to generate CO and VR curves, differing by the manner in which average RAP was varied. One set applied constant RAPs, while the other set applied pulsatile RAPs. Accurate prediction of intact, average CO and RAP was achieved only by intersecting the CO and VR curves generated with pulsatile RAPs because of the pulsatility and nonlinearity (e.g., systemic venous collapse) of the intact model. The CO and VR curves generated with pulsatile RAPs were also practically independent. This theoretical study therefore supports the validity of Guyton's graphical analysis.

Scientific Assistant Virtual Laboratory (SAVL)

NASA Astrophysics Data System (ADS)

Alaghband, Gita; Fardi, Hamid; Gnabasik, David

2007-03-01

The Scientific Assistant Virtual Laboratory (SAVL) is a scientific discovery environment, an interactive simulated virtual laboratory, for learning physics and mathematics. The purpose of this computer-assisted intervention is to improve middle and high school student interest, insight and scores in physics and mathematics. SAVL develops scientific and mathematical imagination in a visual, symbolic, and experimental simulation environment. It directly addresses the issues of scientific and technological competency by providing critical thinking training through integrated modules. This on-going research provides a virtual laboratory environment in which the student directs the building of the experiment rather than observing a packaged simulation. SAVL: * Engages the persistent interest of young minds in physics and math by visually linking simulation objects and events with mathematical relations. * Teaches integrated concepts by the hands-on exploration and focused visualization of classic physics experiments within software. * Systematically and uniformly assesses and scores students by their ability to answer their own questions within the context of a Master Question Network. We will demonstrate how the Master Question Network uses polymorphic interfaces and C# lambda expressions to manage simulation objects.

Clamping characteristics study on different types of clamping unit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiao, Zhiwei; Liu, Haichao; Xie, Pengcheng

2015-05-22

Plastic products are becoming more and more widely used in aerospace, IT, digital electronics and many other fields. With the development of technology, the requirement of product precision is getting higher and higher. However, type and working performance of clamping unit play a decisive role in product precision. Clamping characteristics of different types of clamping unit are discussed in this article, which use finite element numerical analysis method through the software ABAQUS to study the clamping uniformity, and detect the clamping force repeatability precision. The result shows that compared with toggled three-platen clamping unit, clamping characteristics of internal circulation two-platenmore » clamping unit are better, for instance, its mold cavity deformation and force that bars and mold parting surface suffered are more uniform, and its clamping uniformity and repeatability precision is also better.« less

Numerical Model Studies of the Martian Mesoscale Circulations

NASA Technical Reports Server (NTRS)

Segal, M.; Arritt, R. W.

1996-01-01

Studies concerning mesoscale topographical effects on Martian flows examined low-level jets in the near equatorial latitudes and the dynamical intensification of flow by steep terrain. Continuation of work from previous years included evaluating the dissipation of cold air mass outbreaks due to enhanced sensible heat flux, further sensitivity and scaling evaluations for generalization of the characteristics of Martian mesoscale circulation caused by horizontal sensible heat-flux gradients, and evaluations of the significance that non-uniform surface would have on enhancing the polar CO2 ice sublimation during the spring. The sensitivity of maximum and minimum atmospheric temperatures to changes in wind speed, surface albedo, and deep soil temperature was investigated.

Method and apparatus for spatially uniform electropolishing and electrolytic etching

DOEpatents

Mayer, Steven T.; Contolini, Robert J.; Bernhardt, Anthony F.

1992-01-01

In an electropolishing or electrolytic etching apparatus the anode is separated from the cathode to prevent bubble transport to the anode and to produce a uniform current distribution at the anode by means of a solid nonconducting anode-cathode barrier. The anode extends into the top of the barrier and the cathode is outside the barrier. A virtual cathode hole formed in the bottom of the barrier below the level of the cathode permits current flow while preventing bubble transport. The anode is rotatable and oriented horizontally facing down. An extended anode is formed by mounting the workpiece in a holder which extends the electropolishing or etching area beyond the edge of the workpiece to reduce edge effects at the workpiece. A reference electrode controls cell voltage. Endpoint detection and current shut-off stop polishing. Spatially uniform polishing or etching can be rapidly performed.

Method and apparatus for spatially uniform electropolishing and electrolytic etching

DOEpatents

Mayer, S.T.; Contolini, R.J.; Bernhardt, A.F.

1992-03-17

In an electropolishing or electrolytic etching apparatus the anode is separated from the cathode to prevent bubble transport to the anode and to produce a uniform current distribution at the anode by means of a solid nonconducting anode-cathode barrier. The anode extends into the top of the barrier and the cathode is outside the barrier. A virtual cathode hole formed in the bottom of the barrier below the level of the cathode permits current flow while preventing bubble transport. The anode is rotatable and oriented horizontally facing down. An extended anode is formed by mounting the workpiece in a holder which extends the electropolishing or etching area beyond the edge of the workpiece to reduce edge effects at the workpiece. A reference electrode controls cell voltage. Endpoint detection and current shut-off stop polishing. Spatially uniform polishing or etching can be rapidly performed. 6 figs.

Meso-beta scale numerical simulation studies of terrain-induced jet streak mass/momentum perturbations

NASA Technical Reports Server (NTRS)

Lin, Yuh-Lang; Kaplan, Michael L.

1993-01-01

The first section is on 3-D numerical modeling of terrain-induced circulations and covers the following: (1) additional insights into gravity wave generation mechanisms based on the control simulation; (2) ongoing nested-grid numerical simulations; (3) work to be completed during the remainder of FY-93; and (4) work objectives for FY-94. The second section is on linear theory and theoretical modeling and covers the following: (1) the free response of a uniform barotropic flow to an initially stationary unbalanced (ageostrophic) zonal wind anomaly; and (2) the free response of a uniform barotropic flow to an initially stationary balanced zonal wind anomaly.

Automatic Configuration of Programmable Logic Controller Emulators

DTIC Science & Technology

2015-03-01

25 11 Example tree generated using UPGMA [Edw13] . . . . . . . . . . . . . . . . . . . . 33 12 Example sequence alignment for two... UPGMA Unweighted Pair Group Method with Arithmetic Mean URL uniform resource locator VM virtual machine XML Extensible Markup Language xx List of...appearance in the ses- sion, and then they are clustered again using Unweighted Pair Group Method with Arithmetic Mean ( UPGMA ) with a distance matrix based

The Invisible Obstacle to Educational Equality: Gender Bias in Textbooks

ERIC Educational Resources Information Center

Blumberg, Rae Lesser

2008-01-01

Gender bias in textbooks (GBIT) is a low-profile education issue, given the 72,000,000 children who still have no access to schooling, but this article argues that GBIT is: (1) an important, (2) near-universal, (3) remarkably uniform, (4) quite persistent but (5) virtually invisible obstacle on the road to gender equality in education--an obstacle…

Bifocal computational near eye light field displays and Structure parameters determination scheme for bifocal computational display.

PubMed

Liu, Mali; Lu, Chihao; Li, Haifeng; Liu, Xu

2018-02-19

We propose a bifocal computational near eye light field display (bifocal computational display) and structure parameters determination scheme (SPDS) for bifocal computational display that achieves greater depth of field (DOF), high resolution, accommodation and compact form factor. Using a liquid varifocal lens, two single-focal computational light fields are superimposed to reconstruct a virtual object's light field by time multiplex and avoid the limitation on high refresh rate. By minimizing the deviation between reconstructed light field and original light field, we propose a determination framework to determine the structure parameters of bifocal computational light field display. When applied to different objective to SPDS, it can achieve high average resolution or uniform resolution display over scene depth range. To analyze the advantages and limitation of our proposed method, we have conducted simulations and constructed a simple prototype which comprises a liquid varifocal lens, dual-layer LCDs and a uniform backlight. The results of simulation and experiments with our method show that the proposed system can achieve expected performance well. Owing to the excellent performance of our system, we motivate bifocal computational display and SPDS to contribute to a daily-use and commercial virtual reality display.

Scalable Indoor Localization via Mobile Crowdsourcing and Gaussian Process

PubMed Central

Chang, Qiang; Li, Qun; Shi, Zesen; Chen, Wei; Wang, Weiping

2016-01-01

Indoor localization using Received Signal Strength Indication (RSSI) fingerprinting has been extensively studied for decades. The positioning accuracy is highly dependent on the density of the signal database. In areas without calibration data, however, this algorithm breaks down. Building and updating a dense signal database is labor intensive, expensive, and even impossible in some areas. Researchers are continually searching for better algorithms to create and update dense databases more efficiently. In this paper, we propose a scalable indoor positioning algorithm that works both in surveyed and unsurveyed areas. We first propose Minimum Inverse Distance (MID) algorithm to build a virtual database with uniformly distributed virtual Reference Points (RP). The area covered by the virtual RPs can be larger than the surveyed area. A Local Gaussian Process (LGP) is then applied to estimate the virtual RPs’ RSSI values based on the crowdsourced training data. Finally, we improve the Bayesian algorithm to estimate the user’s location using the virtual database. All the parameters are optimized by simulations, and the new algorithm is tested on real-case scenarios. The results show that the new algorithm improves the accuracy by 25.5% in the surveyed area, with an average positioning error below 2.2 m for 80% of the cases. Moreover, the proposed algorithm can localize the users in the neighboring unsurveyed area. PMID:26999139

Linear Instability Analysis of non-uniform Bubbly Mixing layer with Two-Fluid model

NASA Astrophysics Data System (ADS)

Sharma, Subash; Chetty, Krishna; Lopez de Bertodano, Martin

We examine the inviscid instability of a non-uniform adiabatic bubbly shear layer with a Two-Fluid model. The Two-Fluid model is made well-posed with the closure relations for interfacial forces. First, a characteristic analysis is carried out to study the well posedness of the model over range of void fraction with interfacial forces for virtual mass, interfacial drag, interfacial pressure. A dispersion analysis then allow us to obtain growth rate and wavelength. Then, the well-posed two-fluid model is solved using CFD to validate the results obtained with the linear stability analysis. The effect of the void fraction and the distribution profile on stability is analyzed.

Apparatus, components and operating methods for circulating fluidized bed transport gasifiers and reactors

DOEpatents

Vimalchand, Pannalal; Liu, Guohai; Peng, Wan Wang

2015-02-24

The improvements proposed in this invention provide a reliable apparatus and method to gasify low rank coals in a class of pressurized circulating fluidized bed reactors termed "transport gasifier." The embodiments overcome a number of operability and reliability problems with existing gasifiers. The systems and methods address issues related to distribution of gasification agent without the use of internals, management of heat release to avoid any agglomeration and clinker formation, specific design of bends to withstand the highly erosive environment due to high solid particles circulation rates, design of a standpipe cyclone to withstand high temperature gasification environment, compact design of seal-leg that can handle high mass solids flux, design of nozzles that eliminate plugging, uniform aeration of large diameter Standpipe, oxidant injection at the cyclone exits to effectively modulate gasifier exit temperature and reduction in overall height of the gasifier with a modified non-mechanical valve.

Mussel-inspired functionalization of graphene for synthesizing Ag-polydopamine-graphene nanosheets as antibacterial materials

NASA Astrophysics Data System (ADS)

Zhang, Zhe; Zhang, Jing; Zhang, Bailin; Tang, Jilin

2012-12-01

Mussels have been shown to attach to virtually all types of inorganic and organic surfaces via their adhesive proteins. The adhesive proteins secreted by mussels contain high concentrations of catechol and amine functional groups, which have similar functional groups with polydopamine (PDA). Inspired by mussels, a mild and environmentally friendly method was used to synthesize Ag nanoparticles (Ag NPs) on functionalized PDA-graphene nanosheets (PDA-GNS) with uniform and high dispersion. First, a uniform layer of PDA was coated on graphene oxide (GO) by polymerizing dopamine (DA) at room temperature. During the process GO was reduced by the DA. The PDA layer on the surface of GNS can be used as a nanoscale guide to form uniform Ag NPs on the surface of PDA-GNS. The obtained Ag-PDA-GNS hybrid materials are characterized by atomic force microscopy, transmission electron microscopy, UV-vis spectroscopy, Raman spectroscopy, X-ray photo-electron spectroscopy, X-ray diffraction, and thermal gravimetric analysis. The resultant Ag-PDA-GNS hybrid materials exhibited strong antibacterial properties to both Gram-negative and Gram-positive bacteria due to the synergistic effect of GNS and Ag NPs.Mussels have been shown to attach to virtually all types of inorganic and organic surfaces via their adhesive proteins. The adhesive proteins secreted by mussels contain high concentrations of catechol and amine functional groups, which have similar functional groups with polydopamine (PDA). Inspired by mussels, a mild and environmentally friendly method was used to synthesize Ag nanoparticles (Ag NPs) on functionalized PDA-graphene nanosheets (PDA-GNS) with uniform and high dispersion. First, a uniform layer of PDA was coated on graphene oxide (GO) by polymerizing dopamine (DA) at room temperature. During the process GO was reduced by the DA. The PDA layer on the surface of GNS can be used as a nanoscale guide to form uniform Ag NPs on the surface of PDA-GNS. The obtained Ag-PDA-GNS hybrid materials are characterized by atomic force microscopy, transmission electron microscopy, UV-vis spectroscopy, Raman spectroscopy, X-ray photo-electron spectroscopy, X-ray diffraction, and thermal gravimetric analysis. The resultant Ag-PDA-GNS hybrid materials exhibited strong antibacterial properties to both Gram-negative and Gram-positive bacteria due to the synergistic effect of GNS and Ag NPs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr32092d

[Academic heritage of Jiu huang ben cao (Materia Medica for Relief of Famines) in Japan].

PubMed

He, Huiling; Xiao, Yongzhi

2014-11-01

Jiu huang ben cao (Materia Medica for Relief of Famines) was the first monograph on famines herbal in the history of China, which creates a new research field of edible plants. Around the middle and late 17th century, Jiu huang ben cao was spread to Japan and aroused great attention of famous Japanese herbalists. Thus, all versions of different edition systems were circulated in Japan. Later, some famous Japanese scholar ssuccessively quoted texts of Jiu huang ben cao from the Nong zheng quan shu (Whole book on Agricultural Administration) spread in Japan, and block-printed it as an independent work. As a result, Jiu huang ben cao virtually circulated widely in Japan.

Virtual planning in orthognathic surgery.

PubMed

Stokbro, K; Aagaard, E; Torkov, P; Bell, R B; Thygesen, T

2014-08-01

Numerous publications regarding virtual surgical planning protocols have been published, most reporting only one or two case reports to emphasize the hands-on planning. None have systematically reviewed the data published from clinical trials. This systematic review analyzes the precision and accuracy of three-dimensional (3D) virtual surgical planning of orthognathic procedures compared with the actual surgical outcome following orthognathic surgery reported in clinical trials. A systematic search of the current literature was conducted to identify clinical trials with a sample size of more than five patients, comparing the virtual surgical plan with the actual surgical outcome. Search terms revealed a total of 428 titles, out of which only seven articles were included, with a combined sample size of 149 patients. Data were presented in three different ways: intra-class correlation coefficient, 3D surface area with a difference <2mm, and linear and angular differences in three dimensions. Success criteria were set at 2mm mean difference in six articles; 125 of the 133 patients included in these articles were regarded as having had a successful outcome. Due to differences in the presentation of data, meta-analysis was not possible. Virtual planning appears to be an accurate and reproducible method for orthognathic treatment planning. A more uniform presentation of the data is necessary to allow the performance of a meta-analysis. Currently, the software system most often used for 3D virtual planning in clinical trials is SimPlant (Materialise). More independent clinical trials are needed to further validate the precision of virtual planning. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. All rights reserved.

[Use of "NovoSeven" (rFVIIa) hemostatic in patients operated with extracorporeal blood circulation].

PubMed

Dement'eva, I I; Sandrikov, V A; Charnaia, M A; Morozov, Iu A; Trekova, N A; Eremenko, A A

2004-01-01

The "NovoSeven" drug was used in 25 patients (male - 18, female - 7) operated on the heart and main vessels including with artificial extracorporeal circulation (AEC). Patients did not have any clinically significant impairment in blood circulation before surgery. Perioperatively, all of them and, immediately after surgery, 4 them had uncontrollable hemorrhages at 10-25 ml/min in spite of extensive hemostatic therapy, including freshly frozen plasma, cryoprecipitate, thromboconcentrate, trasilol and ?-amine acid. Yet in 30 min after "NovoSeven" administration, hemorrhages seized virtually in all patients irrespective of a surgical intervention. It normalized the hemostasis by it differential action on an impairment depending on an activated or suppressed coagulation. Thus, the conclusion is that the "NovoSeven" (rFVIIa) is an effective hemostatic ensuring the correction of massive intra- and postoperative blood losses in cardiosurgery patients. The drug cuts the need in using the donor-blood components, thus, diminishing the risk of multi organ failure that can develop immediately after surgery.

Numerous uncharacterized and highly divergent microbes which colonize humans are revealed by circulating cell-free DNA

PubMed Central

Camunas-Soler, Joan; Kertesz, Michael; De Vlaminck, Iwijn; Koh, Winston; Pan, Wenying; Martin, Lance; Neff, Norma F.; Okamoto, Jennifer; Wong, Ronald J.; Kharbanda, Sandhya; El-Sayed, Yasser; Blumenfeld, Yair; Stevenson, David K.; Shaw, Gary M.; Wolfe, Nathan D.; Quake, Stephen R.

2017-01-01

Blood circulates throughout the human body and contains molecules drawn from virtually every tissue, including the microbes and viruses which colonize the body. Through massive shotgun sequencing of circulating cell-free DNA from the blood, we identified hundreds of new bacteria and viruses which represent previously unidentified members of the human microbiome. Analyzing cumulative sequence data from 1,351 blood samples collected from 188 patients enabled us to assemble 7,190 contiguous regions (contigs) larger than 1 kbp, of which 3,761 are novel with little or no sequence homology in any existing databases. The vast majority of these novel contigs possess coding sequences, and we have validated their existence both by finding their presence in independent experiments and by performing direct PCR amplification. When their nearest neighbors are located in the tree of life, many of the organisms represent entirely novel taxa, showing that microbial diversity within the human body is substantially broader than previously appreciated. PMID:28830999

Venus' superrotation, mixing length theory and eddy diffusion - A parametric study

NASA Technical Reports Server (NTRS)

Mayr, H. G.; Harris, I.; Schatten, K. H.; Stevens-Rayburn, D. R.; Chan, K. L.

1988-01-01

The concept of the Hadley mechanism is adopted to describe the axisymmetric circulation of the Venus atmosphere. It is shown that, for the atmosphere of a slowly rotating planet such as Venus, a form of the nonliner 'closure' (self-consistent solution) of the fluid dynamics system which constrains the magnitude of the eddy diffusion coefficients can be postulated. A nonlinear one-layer spectral model of the zonally symmetric circulation was then used to establish the relationship between the heat source, the meridional circulation, and the eddy diffusion coefficients, yielding large zonal velocities. Computer experiments indicated that proportional changes in the heat source and eddy diffusion coefficients do not significantly change the zonal velocities. It was also found that, for large eddy diffusion coefficients, the meridional velocity is virtually constant; below a threshold in the diffusion rate, the meridional velocity decreases; and, for large eddy diffusion and small heating rates, the zonal velocities decrease with decreasing planetary rotation rates.

Influence of RF channels mismatch and mutual coupling phenomenon on performance of a multistatic passive radar

NASA Astrophysics Data System (ADS)

Hossa, Robert; Górski, Maksymilian

2010-09-01

In the paper we analyze the influence of RF channels mismatch and mutual coupling effect on the performance of the multistatic passive radar with Uniform Circular Array (UCA) configuration. The problem was tested intensively in numerous different scenarios with a reference virtual multistatic passive radar. Finally, exemplary results of the computer software simulations are provided and discussed.

The remarkable chemical uniformity of Apollo 16 layered deep drill core section 60002

NASA Technical Reports Server (NTRS)

Nava, D. F.; Philpotts, J. A.; Lindstrom, M. M.; Schuhmann, P. J.; Lindstrom, D. J.

1976-01-01

Atomic absorption and colorimetric spectrophotometers were used to determine major- and minor-element abundances in 12 samples from layered section 60002 of the Apollo 16 deep drill core. It is suggested that gardening of a relatively thick local unit produced the layering in this section in such a manner that the proportions of materials of different compositions remained virtually unchanged.

Source imaging of drums in the APNEA system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hensley, D.

1995-12-31

The APNea System is a neutron assay device utilizing both a passive mode and a differential-dieaway active mode. The total detection efficiency is not spatially uniform, even for an empty chamber, and a drum matrix in the chamber can severely distort this response. In order to achieve a response which is independent of the way the source material is distributed in a drum, an imaging procedure has been developed which treats the drum as a number of virtual (sub)volumes. Since each virtual volume of source material is weighted with the appropriate instrument parameters (detection efficiency and thermal flux), the finalmore » assay result is essentially independent of the actual distribution of the source material throughout the drum and its matrix.« less

Vertical Distribution of Radiation Stress for Non-linear Shoaling Waves

NASA Astrophysics Data System (ADS)

Webb, B. M.; Slinn, D. N.

2004-12-01

The flux of momentum directed shoreward by an incident wave field, commonly referred to as the radiation stress, plays a significant role in nearshore circulation and, therefore, has a profound impact on the transport of pollutants, biota, and sediment in nearshore systems. Having received much attention since the seminal work of Longuet-Higgins and Stewart in the early 1960's, use of the radiation stress concept continues to be refined and evidence of its utility is widespread in literature pertaining to coastal and ocean science. A number of investigations, both numerical and analytical in nature, have used the concept of the radiation stress to derive appropriate forcing mechanisms that initiate cross-shore and longshore circulation, but typically in a depth-averaged sense due to a lack of information concerning the vertical distribution of the wave stresses. While depth-averaged nearshore circulation models are still widely used today, advancements in technology have permitted the adaptation of three-dimensional (3D) modeling techniques to study flow properties of complex nearshore circulation systems. It has been shown that the resulting circulation in these 3D models is very sensitive to the vertical distribution of the nearshore forcing, which have often been implemented as either depth-uniform or depth-linear distributions. Recently, analytical expressions describing the vertical structure of radiation stress components have appeared in the literature (see Mellor, 2003; Xia et al., 2004) but do not fully describe the magnitude and structure in the region bound by the trough and crest of non-linear, propagating waves. Utilizing a three-dimensional, non-linear, numerical model that resolves the time-dependent free surface, we present mean flow properties resulting from a simulation of Visser's (1984, 1991) laboratory experiment on uniform longshore currents. More specifically, we provide information regarding the vertical distribution of radiation stress components (Sxx and Sxy) resulting from obliquely incident, non-linear shoaling waves. Vertical profiles of the radiation stress components predicted by the numerical model are compared with published analytical solutions, expressions given by linear theory, and observations from an investigation employing second-order cnoidal wave theory.

Solar Resource Assessment with Sky Imagery and a Virtual Testbed for Sky Imager Solar Forecasting

NASA Astrophysics Data System (ADS)

Kurtz, Benjamin Bernard

In recent years, ground-based sky imagers have emerged as a promising tool for forecasting solar energy on short time scales (0 to 30 minutes ahead). Following the development of sky imager hardware and algorithms at UC San Diego, we present three new or improved algorithms for sky imager forecasting and forecast evaluation. First, we present an algorithm for measuring irradiance with a sky imager. Sky imager forecasts are often used in conjunction with other instruments for measuring irradiance, so this has the potential to decrease instrumentation costs and logistical complexity. In particular, the forecast algorithm itself often relies on knowledge of the current irradiance which can now be provided directly from the sky images. Irradiance measurements are accurate to within about 10%. Second, we demonstrate a virtual sky imager testbed that can be used for validating and enhancing the forecast algorithm. The testbed uses high-quality (but slow) simulations to produce virtual clouds and sky images. Because virtual cloud locations are known, much more advanced validation procedures are possible with the virtual testbed than with measured data. In this way, we are able to determine that camera geometry and non-uniform evolution of the cloud field are the two largest sources of forecast error. Finally, with the assistance of the virtual sky imager testbed, we develop improvements to the cloud advection model used for forecasting. The new advection schemes are 10-20% better at short time horizons.

Development of the CSNS Lambertson magnet with very low stray field

NASA Astrophysics Data System (ADS)

Wu, Yuwen; Kang, Wen; Chen, Yuan; Wu, Xi; Li, Shuai; Wang, Lei; Deng, Changdong; Li, Li; Zhou, Jianxin; Liu, Yiqin

2018-02-01

In this paper, the magnetic and mechanical design of Lambertson are studied, and then magnetic field measurements are introduced. The results show that the integral field uniformity and effective length meet the physical requirements. The shielding measures shield the stray field effectively and the stray field along the circulating beam orbit is at a very low level.

Natural convection in square cavity filled with ferrofluid saturated porous medium in the presence of uniform magnetic field

NASA Astrophysics Data System (ADS)

Javed, Tariq; Mehmood, Z.; Abbas, Z.

2017-02-01

This article contains numerical results for free convection through square enclosure enclosing ferrofluid saturated porous medium when uniform magnetic field is applied upon the flow along x-axis. Heat is provided through bottom wall and a square blockage placed near left or right bottom corner of enclosure as a heat source. Left and right vertical boundaries of the cavity are considered insulated while upper wall is taken cold. The problem is modelled in terms of system of nonlinear partial differential equations. Finite element method has been adopted to compute numerical simulations of mathematical problem for wide range of pertinent flow parameters including Rayleigh number, Hartman number, Darcy number and Prandtl number. Analysis of results reveals that the strength of streamline circulation is an increasing function of Darcy and Prandtl number where convection heat transfer is dominant for large values of these parameters whereas increase in Hartman number has opposite effects on isotherms and streamline circulations. Thermal conductivity and hence local heat transfer rate of fluid gets increased when ferroparticles are introduced in the fluid. Average Nusselt number increases with increase in Darcy and Rayleigh numbers while it is decreases when Hartman number is increased.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trianti, Nuri, E-mail: nuri.trianti@gmail.com; Nurjanah,; Su’ud, Zaki

Thermalhydraulic of reactor core is the thermal study on fluids within the core reactor, i.e. analysis of the thermal energy transfer process produced by fission reaction from fuel to the reactor coolant. This study include of coolant temperature and reactor power density distribution. The purposes of this analysis in the design of nuclear power plant are to calculate the coolant temperature distribution and the chimney height so natural circulation could be occurred. This study was used boiling water reactor (BWR) with cylinder type reactor core. Several reactor core properties such as linear power density, mass flow rate, coolant density andmore » inlet temperature has been took into account to obtain distribution of coolant density, flow rate and pressure drop. The results of calculation are as follows. Thermal hydraulic calculations provide the uniform pressure drop of 1.1 bar for each channels. The optimum mass flow rate to obtain the uniform pressure drop is 217g/s. Furthermore, from the calculation it could be known that outlet temperature is 288°C which is the saturated fluid’s temperature within the system. The optimum chimney height for natural circulation within the system is 14.88 m.« less

Tropical Convection and Climate Processes in a Cumulus Ensemble Model

NASA Technical Reports Server (NTRS)

Sui, Chung-Hsiung

1999-01-01

Local convective-radiative equilibrium states of the tropical atmosphere are determined by the following external forcing: 1) Insolation, 2) Surface heat and moisture exchanges (primarily radiation and evaporation), 3) Heating and moistening induced by large-scale circulation. Understanding the equilibrium states of the tropical atmosphere in different external forcing conditions is of vital importance for studying cumulus parameterization, climate feedbacks, and climate changes. We extend our previous study using the Goddard Cumulus Ensemble (GCE) Model which resolves convective-radiative processes more explicitly than global climate models do. Several experiments are carried out under fixed insolation and sea surface temperature. The prescribed SST consists of a uniform warm pool (29C) surrounded by uniform cold SST (26C). The model produces "Walker"-type circulation with the ascending branch of the model atmosphere more humid than the descending part, but the vertically integrated temperature does not show a horizontal gradient. The results are compared with satellite measured moisture by SSM/I (Special Sensor Microwave/Imager) and temperature by MSU in the ascending and descending tropical atmosphere. The vertically integrated temperature and humidity in the two model regimes are comparable to the observed values in the tropics.

In vivo assessment of regional mechanics post-myocardial infarction: A focus on the road ahead.

PubMed

Romito, Eva; Shazly, Tarek; Spinale, Francis G

2017-10-01

Cardiovascular disease, particularly the occurrence of myocardial infarction (MI), remains a leading cause of morbidity and mortality (Go et al., Circulation 127: e6-e245, 2013; Go et al. Circulation 129: e28-e292, 2014). There is growing recognition that a key factor for post-MI outcomes is adverse remodeling and changes in the regional structure, composition, and mechanical properties of the MI region itself. However, in vivo assessment of regional mechanics post-MI can be confounded by the species, temporal aspects of MI healing, as well as size, location, and extent of infarction across myocardial wall. Moreover, MI regional mechanics have been assessed over varying phases of the cardiac cycle, and thus, uniform conclusions regarding the material properties of the MI region can be difficult. This review assesses past studies that have performed in vivo measures of MI mechanics and attempts to provide coalescence on key points from these studies, as well as offer potential recommendations for unifying approaches in terms of regional post-MI mechanics. A uniform approach to biophysical measures of import will allow comparisons across studies, as well as provide a basis for potential therapeutic markers.

Contribution made by parabiosis to the understanding of energy balance regulation

PubMed Central

Harris, Ruth

2013-01-01

Parabiosis is a chronic preparation that allows exchange of whole blood between two animals. It has been used extensively to test for involvement of circulating factors in feedback regulation of physiological systems. The total blood volume of each animal exchanges approximately ten times each day, therefore, factors that are rapidly cleared from the circulation do not reach equilibrium across the parabiotic union whereas those with a long half-life achieve a uniform concentration and bioactivity in both members of a pair. Involvement of a circulating factor in the regulation of energy balance was first demonstrated when one member of a pair of parabiosed rats became hyperphagic and obese following bilateral lesioning of the ventromedial hypothalamus. The non-lesioned partner stopped eating, lost a large amount of weight and appeared to be responding to a circulating “satiety” factor released by the obese rat. These results were confirmed using different techniques to induce obesity in one member of a pair. Studies with phenotypically similar ob/ob obese and db/db diabetic mice indicated that the obese mouse lacked a circulating signal that regulated energy balance, whereas the diabetic mouse appeared insensitive to such a signal. Positional cloning studies identified leptin as the circulating factor and subsequent parabiosis studies confirmed leptin’s ability to exchange effectively between parabionts. These studies also suggest the presence of additional unidentified factors that influence body composition. PMID:23470554

Software for Building Models of 3D Objects via the Internet

NASA Technical Reports Server (NTRS)

Schramer, Tim; Jensen, Jeff

2003-01-01

The Virtual EDF Builder (where EDF signifies Electronic Development Fixture) is a computer program that facilitates the use of the Internet for building and displaying digital models of three-dimensional (3D) objects that ordinarily comprise assemblies of solid models created previously by use of computer-aided-design (CAD) programs. The Virtual EDF Builder resides on a Unix-based server computer. It is used in conjunction with a commercially available Web-based plug-in viewer program that runs on a client computer. The Virtual EDF Builder acts as a translator between the viewer program and a database stored on the server. The translation function includes the provision of uniform resource locator (URL) links to other Web-based computer systems and databases. The Virtual EDF builder can be used in two ways: (1) If the client computer is Unix-based, then it can assemble a model locally; the computational load is transferred from the server to the client computer. (2) Alternatively, the server can be made to build the model, in which case the server bears the computational load and the results are downloaded to the client computer or workstation upon completion.

High efficiency virtual impactor

DOEpatents

Loo, Billy W.

1981-01-01

Environmental monitoring of atmospheric air is facilitated by a single stage virtual impactor (11) for separating an inlet flow (Q.sub.O) having particulate contaminants into a coarse particle flow (Q.sub.1) and a fine particle flow (Q.sub.2) to enable collection of such particles on different filters (19a, 19b) for separate analysis. An inlet particle acceleration nozzle (28) and coarse particle collection probe member (37) having a virtual impaction opening (41) are aligned along a single axis (13) and spaced apart to define a flow separation region (14) at which the fine particle flow (Q.sub.2) is drawn radially outward into a chamber (21) while the coarse particle flow (Q.sub.1) enters the virtual impaction opening (41). Symmetrical outlet means (47) for the chamber (21) provide flow symmetry at the separation region (14) to assure precise separation of particles about a cutpoint size and to minimize losses by wall impaction and gravitational settling. Impulse defocusing means (42) in the probe member (37) provides uniform coarse particle deposition on the filter (19a) to aid analysis. Particle losses of less than 1% for particles in the 0 to 20 micron range may be realized.

Stability of Electrons in the Virtual Cathode Region of an IEC

NASA Astrophysics Data System (ADS)

Kim, Hyng-Jin; Miley, George; Momota, Hiromu

2003-04-01

In the Inertial Electrostatic Confinement (IEC) device, electrons are confined inside a virtual anode that in turn confines ions. Prior stability studies [1, 2] have considered systems in which one species is electrostatically confined by the other, and either or both species are out of local thermal equilibrium. In the present research, electron stability in the virtual cathode region of an ion injected IEC is being studied. The ion density in an IEC is non-uniform due to the radial electrostatic potential, and increases toward the center region. The potential near the virtual cathode is assumed to have a parabolic shape and is determined assuming that the net space charge density is constant in that region. The corresponding ion distribution function is assumed to have the form f = C [sigma] (H W) /L^0.5 and the electron response is taken to be diabatic. Then using a variational principle after linearizing the hydrodynamic equations, stability properties of the electron layer are determined. Results will be presented as a function of injected ion/electron current ratios. 1. L. Chacon and D. C. Barnes, Phys. Plasma 7, 4774 (2000). 2. D. C. Barnes, L. Chacon, and J. M. Finn, Phys. Plasmas 9, 4448 (2002).

ICPP: Approach for Understanding Complexity of Plasma

NASA Astrophysics Data System (ADS)

Sato, Tetsuya

2000-10-01

In this talk I wish to present an IT system that could promote Science of Complexity. In order to deal with a seemingly `complex' phenomenon, which means `beyond analytical manipulation', computer simulation is a viable powerful tool. However, complexity implies a concept beyond the horizon of reductionism. Therefore, rather than simply solving a complex phenomenon for a given boundary condition, one must establish an intelligent way of attacking mutual evolution of a system and its environment. NIFS-TCSC has been developing a prototype system that consists of supercomputers, virtual reality devices and high-speed network system. Let us explain this by picking up a global atmospheric circulation group, global oceanic circulation group and local weather prediction group. Local weather prediction group predicts the local change of the weather such as the creation of cloud and rain in the near future under the global conditions obtained by the global atmospheric and ocean groups. The global groups run simulations by modifying the local heat source/sink evaluated by the local weather prediction and then obtain the global conditions in the next time step. By repeating such a feedback performance one can predict the mutual evolution of the local system and its environment. Mutual information exchanges among multiple groups are carried out instantaneously by the networked common virtual reality space in which 3-D global and local images of the atmospheric and oceanic circulation and the cloud and rain maps are arbitrarily manipulated by any of the groups and commonly viewed. The present networking system has a great advantage that any simulation groups can freely and arbitrarily change their alignment, so that mutual evolution of any stratum system can become tractable by utilizing this network system.

Virtual reality enhanced mannequin (VREM) that is well received by resuscitation experts.

PubMed

Semeraro, Federico; Frisoli, Antonio; Bergamasco, Massimo; Cerchiari, Erga L

2009-04-01

The objective of this study was to test acceptance of, and interest in, a newly developed prototype of virtual reality enhanced mannequin (VREM) on a sample of congress attendees who volunteered to participate in the evaluation session and to respond to a specifically designed questionnaire. A commercial Laerdal HeartSim 4000 mannequin was developed to integrate virtual reality (VR) technologies with specially developed virtual reality software to increase the immersive perception of emergency scenarios. To evaluate the acceptance of a virtual reality enhanced mannequin (VREM), we presented it to a sample of 39 possible users. Each evaluation session involved one trainee and two instructors with a standardized procedure and scenario: the operator was invited by the instructor to wear the data-gloves and the head mounted display and was briefly introduced to the scope of the simulation. The instructor helped the operator familiarize himself with the environment. After the patient's collapse, the operator was asked to check the patient's clinical conditions and start CPR. Finally, the patient started to recover signs of circulation and the evaluation session was concluded. Each participant was then asked to respond to a questionnaire designed to explore the trainee's perception in the areas of user-friendliness, realism, and interaction/immersion. Overall, the evaluation of the system was very positive, as was the feeling of immersion and realism of the environment and simulation. Overall, 84.6% of the participants judged the virtual reality experience as interesting and believed that its development could be very useful for healthcare training. The prototype of the virtual reality enhanced mannequin was well-liked, without interfence by interaction devices, and deserves full technological development and validation in emergency medical training.

Applying the input-output method to account for water footprint and virtual water trade in the Haihe River basin in China.

PubMed

Zhao, Xu; Yang, Hong; Yang, Zhifeng; Chen, Bin; Qin, Yan

2010-12-01

The virtual water strategy which advocates importing water intensive products and exporting products with low water intensity is gradually accepted as one of the options for solving water crisis in severely water scarce regions. However, if we count the virtual water embodied in imported products as the water saved for a region, we might overestimate the saving by including the virtual water that is later re-exported in association with the proceeded products made from the originally imported products. This problem can be avoided by accounting for the saved water through calculating water footprint (WF) in domestic final consumptive products. In this paper, an input-output analysis (IOA) based on the water footprint accounting framework is built to account for WF and virtual water trade of final consumptive products in the water stressed Haihe River basin in China for the year 1997, 2000, and 2002. The input-output transaction tables of the three years are constructed. The results show WF of 46.57, 44.52, and 42.71 billion m(3) for the three years, respectively. These volumes are higher than the water used directly in the corresponding years in the basin. A WF intensity (WFI) indicator is then used to assess if the economic activities in the basin are consistent with the virtual water strategy. The temporal change of the WFI is also decomposed by the index number analysis method. The results showed that the basin was silently importing virtual water through the trade of raw and processed food commodities under the background of the whole economic circulation.

Why rainfall response to El Niño over Maritime Continent is weaker and non-uniform in boreal winter than in boreal summer

NASA Astrophysics Data System (ADS)

Jiang, Leishan; Li, Tim

2017-11-01

Why rainfall response to El Niño is uniform and stronger over the Maritime Continent (MC) during El Niño developing summer and fall but is weaker and non-uniform during El Niño mature winter is investigated through the diagnosis of anomalous large-scale circulation patterns and a local moisture budget analysis. It is found that when anomalous Walker cells across the equatorial Pacific and Indian Ocean are strengthened toward El Niño mature winter, a low-level ascending motion anomaly starts to develop over western MC in northern fall due to topographic lifting (near Sumatra) and anomalous wind convergence (near west Kalimantan). Easterly anomalies, as a part of an anomalous anticyclone in South China Sea (SCS) that is developed during El Niño and a part of the south-easterly from Java Sea associated with anomalous Walker Circulation, bump into the mountain ridge of Sumatra and induce ascending motion anomalies near Sumatra. Meanwhile, the anomalous north-easterly in the southern flank of the anomalous anticyclone over SCS and south-easterly over Java Sea converge into west Kalimantan, leading to ascending motion there. The anomalous ascending motion tend to advect mean moisture upward to moisten lower troposphere in situ. This low-level moistening eventually sets up a convectively unstable stratification and induces a positive precipitation anomaly in the western MC. How the mechanism discussed here is relevant to previous hypotheses and how processes during El Niño might differ during La Niña are discussed.

Developing Air Force Strategic Leadership - A Career Long Process

DTIC Science & Technology

2012-05-14

experience, the Air Force as an organization is more prone to parochialism, myopia and monistic thinking. 27 Besides providing a historical record of... myopia and monistic thinking.” 120 Worden also claims the uniformity of perspective hindered strategic leaders from understanding or recognizing the...discussions in a virtual setting. While the use of social media is a developing concept, some officers have enjoyed early opportunities for PME or

Load Balancing in Structured P2P Networks

NASA Astrophysics Data System (ADS)

Zhu, Yingwu

In this chapter we start by addressing the importance and necessity of load balancing in structured P2P networks, due to three main reasons. First, structured P2P networks assume uniform peer capacities while peer capacities are heterogeneous in deployed P2P networks. Second, resorting to pseudo-uniformity of the hash function used to generate node IDs and data item keys leads to imbalanced overlay address space and item distribution. Lastly, placement of data items cannot be randomized in some applications (e.g., range searching). We then present an overview of load aggregation and dissemination techniques that are required by many load balancing algorithms. Two techniques are discussed including tree structure-based approach and gossip-based approach. They make different tradeoffs between estimate/aggregate accuracy and failure resilience. To address the issue of load imbalance, three main solutions are described: virtual server-based approach, power of two choices, and address-space and item balancing. While different in their designs, they all aim to improve balance on the address space and data item distribution. As a case study, the chapter discusses a virtual server-based load balancing algorithm that strives to ensure fair load distribution among nodes and minimize load balancing cost in bandwidth. Finally, the chapter concludes with future research and a summary.

Carbon Emission Flow in Networks

PubMed Central

Kang, Chongqing; Zhou, Tianrui; Chen, Qixin; Xu, Qianyao; Xia, Qing; Ji, Zhen

2012-01-01

As the human population increases and production expands, energy demand and anthropogenic carbon emission rates have been growing rapidly, and the need to decrease carbon emission levels has drawn increasing attention. The link between energy production and consumption has required the large-scale transport of energy within energy transmission networks. Within this energy flow, there is a virtual circulation of carbon emissions. To understand this circulation and account for the relationship between energy consumption and carbon emissions, this paper introduces the concept of “carbon emission flow in networks” and establishes a method to calculate carbon emission flow in networks. Using an actual analysis of China's energy pattern, the authors discuss the significance of this new concept, not only as a feasible approach but also as an innovative theoretical perspective. PMID:22761988

Isolation of an Enterovirus D68 from Blood from a Child with Pneumonia in Rural Haiti: Close Phylogenetic Linkage with New York Strain.

PubMed

ElBadry, Maha; Lednicky, John; Cella, Eleonora; Telisma, Taina; Chavannes, Sonese; Loeb, Julia; Ciccozzi, Massinno; Okech, Bernard; Beau De Rochars, Valery Madsen; Salemi, Marco; Morris, J Glenn

2016-09-01

We report the detection and isolation of enterovirus D68 from the blood of a 6-year-old child in rural Haiti, who presented with high fever and clinical signs suggestive of pneumonia. On phylogenetic analysis, this Haitian isolate was virtually identical to an enterovirus D68 strain circulating in New York during the same time period.

10 CFR Appendix C to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dishwashers

Code of Federal Regulations, 2014 CFR

2014-01-01

... Preconditioning cycle means any cycle that includes a fill, circulation, and drain to ensure that the water lines... truncated normal cycle without a test load if the dishwasher does not heat water in the normal cycle. 2.6.2... water temperatures encountered in the test cycle. 3.4 Water pressure gauge. The water pressure gauge...

Manual of design and installation of Forest Service water spray dry kiln

Treesearch

L.V. Teesdale

1920-01-01

The best thing that can be said of any dry kiln is that when it is run by a properly informed operator the temperature, humidity, and circulation are constant and uniform. In an endeavor to produce a kiln in which each of these could be regulated independently of the others, the Forest Products Laboratory designed and developed the "Forest Service Humidity...

Wave Field Synthesis of moving sources with arbitrary trajectory and velocity profile.

PubMed

Firtha, Gergely; Fiala, Péter

2017-08-01

The sound field synthesis of moving sound sources is of great importance when dynamic virtual sound scenes are to be reconstructed. Previous solutions considered only virtual sources moving uniformly along a straight trajectory, synthesized employing a linear loudspeaker array. This article presents the synthesis of point sources following an arbitrary trajectory. Under high-frequency assumptions 2.5D Wave Field Synthesis driving functions are derived for arbitrary shaped secondary source contours by adapting the stationary phase approximation to the dynamic description of sources in motion. It is explained how a referencing function should be chosen in order to optimize the amplitude of synthesis on an arbitrary receiver curve. Finally, a finite difference implementation scheme is considered, making the presented approach suitable for real-time applications.

Technical Report Series on Global Modeling and Data Assimilation. Volume 16; Filtering Techniques on a Stretched Grid General Circulation Model

NASA Technical Reports Server (NTRS)

Takacs, Lawrence L.; Sawyer, William; Suarez, Max J. (Editor); Fox-Rabinowitz, Michael S.

1999-01-01

This report documents the techniques used to filter quantities on a stretched grid general circulation model. Standard high-latitude filtering techniques (e.g., using an FFT (Fast Fourier Transformations) to decompose and filter unstable harmonics at selected latitudes) applied on a stretched grid are shown to produce significant distortions of the prognostic state when used to control instabilities near the pole. A new filtering technique is developed which accurately accounts for the non-uniform grid by computing the eigenvectors and eigenfrequencies associated with the stretching. A filter function, constructed to selectively damp those modes whose associated eigenfrequencies exceed some critical value, is used to construct a set of grid-spaced weights which are shown to effectively filter without distortion. Both offline and GCM (General Circulation Model) experiments are shown using the new filtering technique. Finally, a brief examination is also made on the impact of applying the Shapiro filter on the stretched grid.

Diurnal Variability of the inner-shelf circulation in the lee of a cape under upwelling conditions

NASA Astrophysics Data System (ADS)

Lamas, Luisa; Peliz, Álvaro; Marchesiello, Patrick

2013-04-01

The circulation over the inner-shelf is a key component of shelf dynamics and an important mechanism for cross-shore exchange on most shelves. Yet our understanding of the cross-shore circulation and how it depends on different forcing conditions, bathymetry and stratification remains poor due in part to sparse observations and the difficulty of resolving spatial and temporal scales within the inner-shelf. Most studies of cross-shore transport on the inner-shelf consider only a 2D circulation, due to coastal upwelling or downwelling and assume along-shore uniformity. However, divergence in the along-shore and cross-shore flows may occur with the presence of complex coastline topography or subtle bathymetric features, and can drive substantial horizontal cross-shore exchange, with same order of magnitude as coastal upwelling and downwelling. A recent study using observational data collected near cape Sines, Portugal, showed that not only wind, waves and tides are important forcing mechanisms of the inner-shelf circulation, but also that the along-shore pressure gradient plays a major role on driving cross-shore exchange. A modeling study was conducted in order to study the complexity of the inner-shelf dynamics, in the presence of a cape. A simplified configuration was used in order to isolate the effects of individual processes: wind, heat fluxes, tides and waves. The preliminary results of the effects of these processes on the inner-shelf circulation will be presented.

The accuracy of estimates of the overturning circulation from basin-wide mooring arrays

NASA Astrophysics Data System (ADS)

Sinha, B.; Smeed, D. A.; McCarthy, G.; Moat, B. I.; Josey, S. A.; Hirschi, J. J.-M.; Frajka-Williams, E.; Blaker, A. T.; Rayner, D.; Madec, G.

2018-01-01

Previous modeling and observational studies have established that it is possible to accurately monitor the Atlantic Meridional Overturning Circulation (AMOC) at 26.5°N using a coast-to-coast array of instrumented moorings supplemented by direct transport measurements in key boundary regions (the RAPID/MOCHA/WBTS Array). The main sources of observational and structural errors have been identified in a variety of individual studies. Here a unified framework for identifying and quantifying structural errors associated with the RAPID array-based AMOC estimates is established using a high-resolution (eddy resolving at low-mid latitudes, eddy permitting elsewhere) ocean general circulation model, which simulates the ocean state between 1978 and 2010. We define a virtual RAPID array in the model in close analogy to the real RAPID array and compare the AMOC estimate from the virtual array with the true model AMOC. The model analysis suggests that the RAPID method underestimates the mean AMOC by ∼1.5 Sv (1 Sv = 106 m3 s-1) at ∼900 m depth, however it captures the variability to high accuracy. We examine three major contributions to the streamfunction bias: (i) due to the assumption of a single fixed reference level for calculation of geostrophic transports, (ii) due to regions not sampled by the array and (iii) due to ageostrophic transport. A key element in (i) and (iii) is use of the model sea surface height to establish the true (or absolute) geostrophic transport. In the upper 2000 m, we find that the reference level bias is strongest and most variable in time, whereas the bias due to unsampled regions is largest below 3000 m. The ageostrophic transport is significant in the upper 1000 m but shows very little variability. The results establish, for the first time, the uncertainty of the AMOC estimate due to the combined structural errors in the measurement design and suggest ways in which the error could be reduced. Our work has applications to basin-wide circulation measurement arrays at other latitudes and in other basins as well as quantifying systematic errors in ocean model estimates of the AMOC at 26.5°N.

Core body temperature control by total liquid ventilation using a virtual lung temperature sensor.

PubMed

Nadeau, Mathieu; Micheau, Philippe; Robert, Raymond; Avoine, Olivier; Tissier, Renaud; Germim, Pamela Samanta; Vandamme, Jonathan; Praud, Jean-Paul; Walti, Herve

2014-12-01

In total liquid ventilation (TLV), the lungs are filled with a breathable liquid perfluorocarbon (PFC) while a liquid ventilator ensures proper gas exchange by renewal of a tidal volume of oxygenated and temperature-controlled PFC. Given the rapid changes in core body temperature generated by TLV using the lung has a heat exchanger, it is crucial to have accurate and reliable core body temperature monitoring and control. This study presents the design of a virtual lung temperature sensor to control core temperature. In the first step, the virtual sensor, using expired PFC to estimate lung temperature noninvasively, was validated both in vitro and in vivo. The virtual lung temperature was then used to rapidly and automatically control core temperature. Experimentations were performed using the Inolivent-5.0 liquid ventilator with a feedback controller to modulate inspired PFC temperature thereby controlling lung temperature. The in vivo experimental protocol was conducted on seven newborn lambs instrumented with temperature sensors at the femoral artery, pulmonary artery, oesophagus, right ear drum, and rectum. After stabilization in conventional mechanical ventilation, TLV was initiated with fast hypothermia induction, followed by slow posthypothermic rewarming for 1 h, then by fast rewarming to normothermia and finally a second fast hypothermia induction phase. Results showed that the virtual lung temperature was able to provide an accurate estimation of systemic arterial temperature. Results also demonstrate that TLV can precisely control core body temperature and can be favorably compared to extracorporeal circulation in terms of speed.

Water Quality Research Program. Simultaneous, Multiple-Level Withdrawal from a Density Stratified Reservoir

DTIC Science & Technology

1990-11-01

Furusawa , M . 1969. "Experiments on Selective Withdrawal into a Sink from a Uniformly Stratified Fluid--Phenomenon of Layer Separation and Middle-Layer...E. Howington prepared this report. Assisting in the testing were Messrs. Jack E. Davis; Calvin Buie, Jr.; Douglas M . White; and Paul Ahlrich; and Ms...virtually horizontal. Several researchers such as Hino and Furusawa (1969), Croach (1971), Hino (1980), and Farrant (1982) have studied withdrawal

Uniform bulk material processing using multimode microwave radiation

DOEpatents

Varma, Ravi; Vaughn, Worth E.

2000-01-01

An apparatus for generating uniform heating in material contained in a cylindrical vessel is described. TE.sub.10 -mode microwave radiation is coupled into a cylindrical microwave transition such that microwave radiation having TE.sub.11 -, TE.sub.01 - and TM.sub.01 -cylindrical modes is excited therein. By adjusting the intensities of these modes, substantially uniform heating of materials contained in a cylindrical drum which is coupled to the microwave transition through a rotatable choke can be achieved. The use of a poor microwave absorbing insulating cylindrical insert, such as aluminum oxide, for separating the material in the container from the container walls and for providing a volume through which air is circulated is expected to maintain the container walls at room temperature. The use of layer of highly microwave absorbing material, such as SiC, inside of the insulating insert and facing the material to be heated is calculated to improve the heating pattern of the present apparatus.

No evidence for circulating mesenchymal stem cells in patients with organ injury.

PubMed

Hoogduijn, Martin J; Verstegen, Monique M A; Engela, Anja U; Korevaar, Sander S; Roemeling-van Rhijn, Marieke; Merino, Ana; Franquesa, Marcella; de Jonge, Jeroen; Ijzermans, Jan N; Weimar, Willem; Betjes, Michiel G H; Baan, Carla C; van der Laan, Luc J W

2014-10-01

Mesenchymal stem cells (MSC) are present in the bone marrow, from where they are thought to migrate through the blood stream to the sites of injury. However, virtually all tissues contain resident MSC that may contribute to local regenerative and immunomodulatory processes, thereby hypothetically preempting the need for recruiting MSC through the bloodstream. Although there is some indication for circulating MSC in animal models, there is little solid evidence for the mobilization and migration of MSC in the human circulation. In the present study, we were unable to detect MSC in the blood of healthy individuals. We then searched for MSC in the blood of ten patients with end-stage renal disease, ten patients with end-stage liver disease, and in eight heart transplant patients with biopsy-proven rejection by culturing of mononuclear cells under MSC-supporting culture conditions. In none of these patient categories, MSC were identified in the blood. MSC were, however, found in the blood of a severe trauma patient with multiple fractures, suggesting that disruption of bone marrow leads to the release of MSC into the blood stream. The conclusion of this study is that MSC are not recruited into the circulation in patients with injured solid organs and during aggressive immune responses after transplantation.

Comparison of Virtual Oscillator and Droop Control: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Brian B; Rodriguez, Miguel; Dhople, Sairaj

Virtual oscillator control and droop control are two techniques that can be used to ensure synchronization and power sharing of parallel inverters in islanded operation. VOC relies on the implementation of non-linear Van der Pol oscillator equations in the control system of the inverter, acting upon the time-domain instantaneous inverter current and terminal voltage. On the other hand, DC explicitly computes active and reactive power produced by the inverter and relies on limited bandwidth low-pass filters. Even though both methods can be engineered to produce the same steady-state characteristics, their dynamic performances are significantly different. This paper presents analytical andmore » experimental results that aim to compare both methods. It is shown that VOC is inherently faster and enables minimizing the circulating currents. The results are verified using three 120V, 1kW inverters.« less

Milestone Completion Report WBS 1.3.5.05 ECP/VTK-m FY17Q2 [MS-17/01] Better Dynamic Types Design SDA05-1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moreland, Kenneth D.

The FY17Q2 milestone of the ECP/VTK-m project, which is the first milestone, includes the completion of design documents for the introduction of virtual methods into the VTK-m framework. Specifically, the ability from within the code of a device (e.g. GPU or Xeon Phi) to jump to a virtual method specified at run time. This change will enable us to drastically reduce the compile time and the executable code size for the VTK-m library. Our first design introduced the idea of adding virtual functions to classes that are used during algorithm execution. (Virtual methods were previously banned from the so calledmore » execution environment.) The design was straightforward. VTK-m already has the generic concepts of an “array handle” that provides a uniform interface to memory of different structures and an “array portal” that provides generic access to said memory. These array handles and portals use C++ templating to adjust them to different memory structures. This composition provides a powerful ability to adapt to data sources, but requires knowing static types. The proposed design creates a template specialization of an array portal that decorates another array handle while hiding its type. In this way we can wrap any type of static array handle and then feed it to a single compiled instance of a function. The second design focused on the mechanics of implementing virtual methods on parallel devices with a focus on CUDA. Our initial experiments on CUDA showed a very large overhead for using virtual C++ classes with virtual methods, the standard approach. Instead, we are using an alternate method provided by C that uses function pointers. With the completion of this milestone, we are able to move to the implementation of objects with virtual (like) methods. The upshot will be much faster compile times and much smaller library/executable sizes.« less

Autonomic control of circulation in fish: a comparative view.

PubMed

Sandblom, Erik; Axelsson, Michael

2011-11-16

The autonomic nervous system has a central role in the control and co-ordination of the cardiovascular system in all vertebrates. In fish, which represent the largest and most diverse vertebrate group, the autonomic control of the circulation displays a vast variation with a number of interesting deviations from the typical vertebrate pattern. This diversity ranges from virtually no known nervous control of the circulation in hagfish, to a fully developed dual control from both cholinergic and adrenergic nerves in teleost, much resembling the situation found in other vertebrate groups. This review summarizes current knowledge on the role of the autonomic nervous system in the control of the cardiovascular system in fish. We set out by providing an overview of the general trends and patterns in the major fish groups, and then a summary of how the autonomic nervous control is involved in normal daily activities such as barostatic control of blood pressure, as well as adjustments of the cardiovascular system during feeding and environmental hypoxia. Copyright © 2011 Elsevier B.V. All rights reserved.

Ocean Hydrodynamics Numerical Model in Curvilinear Coordinates for Simulating Circulation of the Global Ocean and its Separate Basins.

NASA Astrophysics Data System (ADS)

Gusev, Anatoly; Diansky, Nikolay; Zalesny, Vladimir

2010-05-01

The original program complex is proposed for the ocean circulation sigma-model, developed in the Institute of Numerical Mathematics (INM), Russian Academy of Sciences (RAS). The complex can be used in various curvilinear orthogonal coordinate systems. In addition to ocean circulation model, the complex contains a sea ice dynamics and thermodynamics model, as well as the original system of the atmospheric forcing implementation on the basis of both prescribed meteodata and atmospheric model results. This complex can be used as the oceanic block of Earth climate model as well as for solving the scientific and practical problems concerning the World ocean and its separate oceans and seas. The developed program complex can be effectively used on parallel shared memory computational systems and on contemporary personal computers. On the base of the complex proposed the ocean general circulation model (OGCM) was developed. The model is realized in the curvilinear orthogonal coordinate system obtained by the conformal transformation of the standard geographical grid that allowed us to locate the system singularities outside the integration domain. The horizontal resolution of the OGCM is 1 degree on longitude, 0.5 degree on latitude, and it has 40 non-uniform sigma-levels in depth. The model was integrated for 100 years starting from the Levitus January climatology using the realistic atmospheric annual cycle calculated on the base of CORE datasets. The experimental results showed us that the model adequately reproduces the basic characteristics of large-scale World Ocean dynamics, that is in good agreement with both observational data and results of the best climatic OGCMs. This OGCM is used as the oceanic component of the new version of climatic system model (CSM) developed in INM RAS. The latter is now ready for carrying out the new numerical experiments on climate and its change modelling according to IPCC (Intergovernmental Panel on Climate Change) scenarios in the scope of the CMIP-5 (Coupled Model Intercomparison Project). On the base of the complex proposed the Pacific Ocean circulation eddy-resolving model was realized. The integration domain covers the Pacific from Equator to Bering Strait. The model horizontal resolution is 0.125 degree and it has 20 non-uniform sigma-levels in depth. The model adequately reproduces circulation large-scale structure and its variability: Kuroshio meandering, ocean synoptic eddies, frontal zones, etc. Kuroshio high variability is shown. The distribution of contaminant was simulated that is admittedly wasted near Petropavlovsk-Kamchatsky. The results demonstrate contaminant distribution structure and provide us understanding of hydrological fields formation processes in the North-West Pacific.

10 CFR Appendix I to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Conventional Ranges, Conventional...

Code of Federal Regulations, 2014 CFR

2014-01-01

..., set the clock time to 3:23 and use the average power approach described in Section 5, Paragraph 5.3.2... circulates air internally or externally to the cooking product for a finite period of time after the end of... persist for an indefinite time. An indicator that only shows the user that the product is in the off...

10 CFR Appendix C to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dishwashers

Code of Federal Regulations, 2013 CFR

2013-01-01

....8Preconditioning cycle means any cycle that includes a fill, circulation, and drain to ensure that the water lines... cycle without a test load if the dishwasher does not heat water in the normal cycle. 2.6.2Non-soil... cycle. 3.4Water pressure gauge. The water pressure gauge must have a resolution of one pound per square...

An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras.

PubMed

Bolotnikov, A E; Ackley, K; Camarda, G S; Cherches, C; Cui, Y; De Geronimo, G; Fried, J; Hodges, D; Hossain, A; Lee, W; Mahler, G; Maritato, M; Petryk, M; Roy, U; Salwen, C; Vernon, E; Yang, G; James, R B

2015-07-01

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm(3) detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays' performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.

A Novel Artificial Bee Colony Approach of Live Virtual Machine Migration Policy Using Bayes Theorem

PubMed Central

Xu, Gaochao; Hu, Liang; Fu, Xiaodong

2013-01-01

Green cloud data center has become a research hotspot of virtualized cloud computing architecture. Since live virtual machine (VM) migration technology is widely used and studied in cloud computing, we have focused on the VM placement selection of live migration for power saving. We present a novel heuristic approach which is called PS-ABC. Its algorithm includes two parts. One is that it combines the artificial bee colony (ABC) idea with the uniform random initialization idea, the binary search idea, and Boltzmann selection policy to achieve an improved ABC-based approach with better global exploration's ability and local exploitation's ability. The other one is that it uses the Bayes theorem to further optimize the improved ABC-based process to faster get the final optimal solution. As a result, the whole approach achieves a longer-term efficient optimization for power saving. The experimental results demonstrate that PS-ABC evidently reduces the total incremental power consumption and better protects the performance of VM running and migrating compared with the existing research. It makes the result of live VM migration more high-effective and meaningful. PMID:24385877

Presence Relates to Distinct Outcomes in Two Virtual Environments Employing Different Learning Modalities

PubMed Central

Persky, Susan; Kaphingst, Kimberly A.; McCall, Cade; Lachance, Christina; Beall, Andrew C.; Blascovich, Jim

2009-01-01

Presence in virtual learning environments (VLEs) has been associated with a number of outcome factors related to a user’s ability and motivation to learn. The extant but relatively small body of research suggests that a high level of presence is related to better performance on learning outcomes in VLEs. Different configurations of form and content variables such as those associated with active (self-driven, interactive activities) versus didactic (reading or lecture) learning may, however, influence how presence operates and on what content it operates. We compared the influence of presence between two types of immersive VLEs (i.e., active versus didactic techniques) on comprehension and engagement-related outcomes. The findings revealed that the active VLE promoted greater presence. Although we found no relationship between presence and learning comprehension outcomes for either virtual environment, presence was related to information engagement variables in the didactic immersive VLE but not the active environment. Results demonstrate that presence is not uniformly elicited or effective across immersive VLEs. Educational delivery mode and environment complexity may influence the impact of presence on engagement. PMID:19366319

Presence relates to distinct outcomes in two virtual environments employing different learning modalities.

PubMed

Persky, Susan; Kaphingst, Kimberly A; McCall, Cade; Lachance, Christina; Beall, Andrew C; Blascovich, Jim

2009-06-01

Presence in virtual learning environments (VLEs) has been associated with a number of outcome factors related to a user's ability and motivation to learn. The extant but relatively small body of research suggests that a high level of presence is related to better performance on learning outcomes in VLEs. Different configurations of form and content variables such as those associated with active (self-driven, interactive activities) versus didactic (reading or lecture) learning may, however, influence how presence operates and on what content it operates. We compared the influence of presence between two types of immersive VLEs (i.e., active versus didactic techniques) on comprehension and engagement-related outcomes. The findings revealed that the active VLE promoted greater presence. Although we found no relationship between presence and learning comprehension outcomes for either virtual environment, presence was related to information engagement variables in the didactic immersive VLE but not the active environment. Results demonstrate that presence is not uniformly elicited or effective across immersive VLEs. Educational delivery mode and environment complexity may influence the impact of presence on engagement.

A novel artificial bee colony approach of live virtual machine migration policy using Bayes theorem.

PubMed

Xu, Gaochao; Ding, Yan; Zhao, Jia; Hu, Liang; Fu, Xiaodong

2013-01-01

Green cloud data center has become a research hotspot of virtualized cloud computing architecture. Since live virtual machine (VM) migration technology is widely used and studied in cloud computing, we have focused on the VM placement selection of live migration for power saving. We present a novel heuristic approach which is called PS-ABC. Its algorithm includes two parts. One is that it combines the artificial bee colony (ABC) idea with the uniform random initialization idea, the binary search idea, and Boltzmann selection policy to achieve an improved ABC-based approach with better global exploration's ability and local exploitation's ability. The other one is that it uses the Bayes theorem to further optimize the improved ABC-based process to faster get the final optimal solution. As a result, the whole approach achieves a longer-term efficient optimization for power saving. The experimental results demonstrate that PS-ABC evidently reduces the total incremental power consumption and better protects the performance of VM running and migrating compared with the existing research. It makes the result of live VM migration more high-effective and meaningful.

Distributed Virtual System (DIVIRS) Project

NASA Technical Reports Server (NTRS)

Schorr, Herbert; Neuman, B. Clifford

1993-01-01

As outlined in our continuation proposal 92-ISI-50R (revised) on contract NCC 2-539, we are (1) developing software, including a system manager and a job manager, that will manage available resources and that will enable programmers to program parallel applications in terms of a virtual configuration of processors, hiding the mapping to physical nodes; (2) developing communications routines that support the abstractions implemented in item one; (3) continuing the development of file and information systems based on the virtual system model; and (4) incorporating appropriate security measures to allow the mechanisms developed in items 1 through 3 to be used on an open network. The goal throughout our work is to provide a uniform model that can be applied to both parallel and distributed systems. We believe that multiprocessor systems should exist in the context of distributed systems, allowing them to be more easily shared by those that need them. Our work provides the mechanisms through which nodes on multiprocessors are allocated to jobs running within the distributed system and the mechanisms through which files needed by those jobs can be located and accessed.

DIstributed VIRtual System (DIVIRS) project

NASA Technical Reports Server (NTRS)

Schorr, Herbert; Neuman, B. Clifford

1994-01-01

As outlined in our continuation proposal 92-ISI-. OR (revised) on NASA cooperative agreement NCC2-539, we are (1) developing software, including a system manager and a job manager, that will manage available resources and that will enable programmers to develop and execute parallel applications in terms of a virtual configuration of processors, hiding the mapping to physical nodes; (2) developing communications routines that support the abstractions implemented in item one; (3) continuing the development of file and information systems based on the Virtual System Model; and (4) incorporating appropriate security measures to allow the mechanisms developed in items 1 through 3 to be used on an open network. The goal throughout our work is to provide a uniform model that can be applied to both parallel and distributed systems. We believe that multiprocessor systems should exist in the context of distributed systems, allowing them to be more easily shared by those that need them. Our work provides the mechanisms through which nodes on multiprocessors are allocated to jobs running within the distributed system and the mechanisms through which files needed by those jobs can be located and accessed.

DIstributed VIRtual System (DIVIRS) project

NASA Technical Reports Server (NTRS)

Schorr, Herbert; Neuman, Clifford B.

1995-01-01

As outlined in our continuation proposal 92-ISI-50R (revised) on NASA cooperative agreement NCC2-539, we are (1) developing software, including a system manager and a job manager, that will manage available resources and that will enable programmers to develop and execute parallel applications in terms of a virtual configuration of processors, hiding the mapping to physical nodes; (2) developing communications routines that support the abstractions implemented in item one; (3) continuing the development of file and information systems based on the Virtual System Model; and (4) incorporating appropriate security measures to allow the mechanisms developed in items 1 through 3 to be used on an open network. The goal throughout our work is to provide a uniform model that can be applied to both parallel and distributed systems. We believe that multiprocessor systems should exist in the context of distributed systems, allowing them to be more easily shared by those that need them. Our work provides the mechanisms through which nodes on multiprocessors are allocated to jobs running within the distributed system and the mechanisms through which files needed by those jobs can be located and accessed.

Distributed Virtual System (DIVIRS) project

NASA Technical Reports Server (NTRS)

Schorr, Herbert; Neuman, B. Clifford

1993-01-01

As outlined in the continuation proposal 92-ISI-50R (revised) on NASA cooperative agreement NCC 2-539, the investigators are developing software, including a system manager and a job manager, that will manage available resources and that will enable programmers to develop and execute parallel applications in terms of a virtual configuration of processors, hiding the mapping to physical nodes; developing communications routines that support the abstractions implemented; continuing the development of file and information systems based on the Virtual System Model; and incorporating appropriate security measures to allow the mechanisms developed to be used on an open network. The goal throughout the work is to provide a uniform model that can be applied to both parallel and distributed systems. The authors believe that multiprocessor systems should exist in the context of distributed systems, allowing them to be more easily shared by those that need them. The work provides the mechanisms through which nodes on multiprocessors are allocated to jobs running within the distributed system and the mechanisms through which files needed by those jobs can be located and accessed.

An array of virtual Frisch-grid CdZnTe detectors and a front-end application-specific integrated circuit for large-area position-sensitive gamma-ray cameras

DOE PAGES

Bolotnikov, A. E.; Ackley, K.; Camarda, G. S.; ...

2015-07-28

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe (CZT) detectors coupled to a front-end readout ASIC for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6x6x15 mm 3 detectors grouped into 3x3 sub-arrays of 2x2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readoutmore » electronics. The further enhancement of the arrays’ performance and reduction of their cost are made possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.« less

Towards photorealistic and immersive virtual-reality environments for simulated prosthetic vision: integrating recent breakthroughs in consumer hardware and software.

PubMed

Zapf, Marc P; Matteucci, Paul B; Lovell, Nigel H; Zheng, Steven; Suaning, Gregg J

2014-01-01

Simulated prosthetic vision (SPV) in normally sighted subjects is an established way of investigating the prospective efficacy of visual prosthesis designs in visually guided tasks such as mobility. To perform meaningful SPV mobility studies in computer-based environments, a credible representation of both the virtual scene to navigate and the experienced artificial vision has to be established. It is therefore prudent to make optimal use of existing hardware and software solutions when establishing a testing framework. The authors aimed at improving the realism and immersion of SPV by integrating state-of-the-art yet low-cost consumer technology. The feasibility of body motion tracking to control movement in photo-realistic virtual environments was evaluated in a pilot study. Five subjects were recruited and performed an obstacle avoidance and wayfinding task using either keyboard and mouse, gamepad or Kinect motion tracking. Walking speed and collisions were analyzed as basic measures for task performance. Kinect motion tracking resulted in lower performance as compared to classical input methods, yet results were more uniform across vision conditions. The chosen framework was successfully applied in a basic virtual task and is suited to realistically simulate real-world scenes under SPV in mobility research. Classical input peripherals remain a feasible and effective way of controlling the virtual movement. Motion tracking, despite its limitations and early state of implementation, is intuitive and can eliminate between-subject differences due to familiarity to established input methods.

Asteroid orbital inversion using uniform phase-space sampling

NASA Astrophysics Data System (ADS)

Muinonen, K.; Pentikäinen, H.; Granvik, M.; Oszkiewicz, D.; Virtanen, J.

2014-07-01

We review statistical inverse methods for asteroid orbit computation from a small number of astrometric observations and short time intervals of observations. With the help of Markov-chain Monte Carlo methods (MCMC), we present a novel inverse method that utilizes uniform sampling of the phase space for the orbital elements. The statistical orbital ranging method (Virtanen et al. 2001, Muinonen et al. 2001) was set out to resolve the long-lasting challenges in the initial computation of orbits for asteroids. The ranging method starts from the selection of a pair of astrometric observations. Thereafter, the topocentric ranges and angular deviations in R.A. and Decl. are randomly sampled. The two Cartesian positions allow for the computation of orbital elements and, subsequently, the computation of ephemerides for the observation dates. Candidate orbital elements are included in the sample of accepted elements if the χ^2-value between the observed and computed observations is within a pre-defined threshold. The sample orbital elements obtain weights based on a certain debiasing procedure. When the weights are available, the full sample of orbital elements allows the probabilistic assessments for, e.g., object classification and ephemeris computation as well as the computation of collision probabilities. The MCMC ranging method (Oszkiewicz et al. 2009; see also Granvik et al. 2009) replaces the original sampling algorithm described above with a proposal probability density function (p.d.f.), and a chain of sample orbital elements results in the phase space. MCMC ranging is based on a bivariate Gaussian p.d.f. for the topocentric ranges, and allows for the sampling to focus on the phase-space domain with most of the probability mass. In the virtual-observation MCMC method (Muinonen et al. 2012), the proposal p.d.f. for the orbital elements is chosen to mimic the a posteriori p.d.f. for the elements: first, random errors are simulated for each observation, resulting in a set of virtual observations; second, corresponding virtual least-squares orbital elements are derived using the Nelder-Mead downhill simplex method; third, repeating the procedure two times allows for a computation of a difference for two sets of virtual orbital elements; and, fourth, this orbital-element difference constitutes a symmetric proposal in a random-walk Metropolis-Hastings algorithm, avoiding the explicit computation of the proposal p.d.f. In a discrete approximation, the allowed proposals coincide with the differences that are based on a large number of pre-computed sets of virtual least-squares orbital elements. The virtual-observation MCMC method is thus based on the characterization of the relevant volume in the orbital-element phase space. Here we utilize MCMC to map the phase-space domain of acceptable solutions. We can make use of the proposal p.d.f.s from the MCMC ranging and virtual-observation methods. The present phase-space mapping produces, upon convergence, a uniform sampling of the solution space within a pre-defined χ^2-value. The weights of the sampled orbital elements are then computed on the basis of the corresponding χ^2-values. The present method resembles the original ranging method. On one hand, MCMC mapping is insensitive to local extrema in the phase space and efficiently maps the solution space. This is somewhat contrary to the MCMC methods described above. On the other hand, MCMC mapping can suffer from producing a small number of sample elements with small χ^2-values, in resemblance to the original ranging method. We apply the methods to example near-Earth, main-belt, and transneptunian objects, and highlight the utilization of the methods in the data processing and analysis pipeline of the ESA Gaia space mission.

Analytical approach of laser beam propagation in the hollow polygonal light pipe.

PubMed

Zhu, Guangzhi; Zhu, Xiao; Zhu, Changhong

2013-08-10

An analytical method of researching the light distribution properties on the output end of a hollow n-sided polygonal light pipe and a light source with a Gaussian distribution is developed. The mirror transformation matrices and a special algorithm of removing void virtual images are created to acquire the location and direction vector of each effective virtual image on the entrance plane. The analytical method is demonstrated by Monte Carlo ray tracing. At the same time, four typical cases are discussed. The analytical results indicate that the uniformity of light distribution varies with the structural and optical parameters of the hollow n-sided polygonal light pipe and light source with a Gaussian distribution. The analytical approach will be useful to design and choose the hollow n-sided polygonal light pipe, especially for high-power laser beam homogenization techniques.

A New Dry Flue Gas Desulfurization Process-Underfeed Circulating Spouted Bed

NASA Astrophysics Data System (ADS)

Tao, M.; Jin, B. S.; Yang, Y. P.

Applying an underfeed system, the underfeed circulating spouted bed was designed as a desulfurization reactor. The main objective of the technology is to improve the mixing effect and distribution uniformity of solid particles, and therefore to advance the desulfurization efficiency and calcium utility. In this article, a series of experimental studies were conducted to investigate the fluidization behavior of the solid-gas two-phase flow in the riser. The results show that the technology can distinctly improve the distribution of gas velocity and particle flux on sections compared with the facefeed style. Analysis of pressure fluctuation signals indicates that the operation parameters have significant influence on the flow field in the reaction bed. The existence of injecting flow near the underfeed nozzle has an evident effect on strengthening the particle mixing.

Experimental Study of a Nitrogen Natural Circulation Loop at Low Heat Flux

NASA Astrophysics Data System (ADS)

Baudouy, B.

2010-04-01

A natural convection circulation loop in liquid nitrogen, i.e. an open thermosiphon flow configuration, has been investigated experimentally near atmospheric pressure. The experiments were conducted on a 2 m high loop with a copper tube of 10 mm inner diameter uniformly heated over a length of 0.95 m. Evolution of the total mass flow rate of the loop and the pressure difference along the tube are described. We also report the boiling curves where single phase and two-phase flows are identified with increasing heat flux. We focus our heat transfer analysis on the single phase regime where mixed convection is encountered. A heat transfer coefficient correlation is proposed. We also examine the boiling incipience as a function of the tube height.

Measurement-Based Linear Optics

NASA Astrophysics Data System (ADS)

Alexander, Rafael N.; Gabay, Natasha C.; Rohde, Peter P.; Menicucci, Nicolas C.

2017-03-01

A major challenge in optical quantum processing is implementing large, stable interferometers. We offer a novel approach: virtual, measurement-based interferometers that are programed on the fly solely by the choice of homodyne measurement angles. The effects of finite squeezing are captured as uniform amplitude damping. We compare our proposal to existing (physical) interferometers and consider its performance for BosonSampling, which could demonstrate postclassical computational power in the near future. We prove its efficiency in time and squeezing (energy) in this setting.

The digital media revolution: what it means for the AJR.

PubMed

Kanne, Jeffrey P

2011-07-01

The digital media revolution is in full swing, fueled by rapid growth of the Internet and proliferation of handheld devices capable of accessing electronically data from virtually anywhere. With this growth of digital media, the printing industry is seeing declines in circulation and advertising revenue. Scholarly journals, including the American Journal of Roentgenology, are not immune from this changing paradigm. The scholarly journal of the future should be a platform for the active exchange of new information and ideas.

Grid heterogeneity in in-silico experiments: an exploration of drug screening using DOCK on cloud environments.

PubMed

Yim, Wen-Wai; Chien, Shu; Kusumoto, Yasuyuki; Date, Susumu; Haga, Jason

2010-01-01

Large-scale in-silico screening is a necessary part of drug discovery and Grid computing is one answer to this demand. A disadvantage of using Grid computing is the heterogeneous computational environments characteristic of a Grid. In our study, we have found that for the molecular docking simulation program DOCK, different clusters within a Grid organization can yield inconsistent results. Because DOCK in-silico virtual screening (VS) is currently used to help select chemical compounds to test with in-vitro experiments, such differences have little effect on the validity of using virtual screening before subsequent steps in the drug discovery process. However, it is difficult to predict whether the accumulation of these discrepancies over sequentially repeated VS experiments will significantly alter the results if VS is used as the primary means for identifying potential drugs. Moreover, such discrepancies may be unacceptable for other applications requiring more stringent thresholds. This highlights the need for establishing a more complete solution to provide the best scientific accuracy when executing an application across Grids. One possible solution to platform heterogeneity in DOCK performance explored in our study involved the use of virtual machines as a layer of abstraction. This study investigated the feasibility and practicality of using virtual machine and recent cloud computing technologies in a biological research application. We examined the differences and variations of DOCK VS variables, across a Grid environment composed of different clusters, with and without virtualization. The uniform computer environment provided by virtual machines eliminated inconsistent DOCK VS results caused by heterogeneous clusters, however, the execution time for the DOCK VS increased. In our particular experiments, overhead costs were found to be an average of 41% and 2% in execution time for two different clusters, while the actual magnitudes of the execution time costs were minimal. Despite the increase in overhead, virtual clusters are an ideal solution for Grid heterogeneity. With greater development of virtual cluster technology in Grid environments, the problem of platform heterogeneity may be eliminated through virtualization, allowing greater usage of VS, and will benefit all Grid applications in general.

Electroosmotic Mixing in Nanochannels

NASA Astrophysics Data System (ADS)

Conlisk, A. T.; Chen, Lei

2004-11-01

Electroosmotic flow in nanochannels is characterized by low Reynolds number in which flow mixing is difficult because of the dominance of molecular diffusion. Previous work shows that heterogenerous surface potential could generate a circulation region within the bulk flow near the surface. But all of this work requires that the ionic species be pairs of ions of equal and opposite valence and the distribution of ions is not considered. In the present work the electroosmotic flow in a rectangular channel with non-uniform zeta potential is examined. A model for the two dimensional electroosmotic flow problem is established. The distributions of potential, velocity and mole fractions are calculated numerically. Vortex formation is observed within the bulk flow near the the region of non-uniform zeta potential which suggests mixing can be induced.

Regional Myocardial Blood Flow*

PubMed Central

Sullivan, Jay M.; Taylor, Warren J.; Elliott, William C.; Gorlin, Richard

1967-01-01

A method is described which measures the local effectiveness of the myocardial circulation, expressed as a clearance constant. Uniform clearance constants have been demonstrated in the normal canine and human myocardium. A distinct difference in clearance constants has been demonstrated between the normal canine myocardium and areas of naturally occurring disease. Heterogeneous clearance constants have been found in a majority of human subjects with coronary artery disease—the lowest rates being noted in areas of fibrous aneurysm. PMID:6036537

"TEEB begins now": a virtual moment in the production of natural capital.

PubMed

MacDonald, Kenneth Iain; Corson, Catherine

2012-01-01

This article uses theories of virtualism to analyse the role of The Economics of Ecosystems and Biodiversity (TEEB) project in the production of natural capital. Presented at the 10th Conference of the Parties to the Convention on Biological Diversity, the project seeks to redress the ‘economic invisibility of nature’ by quantifying the value of ecosystems and biodiversity. This endeavour to put an economic value on ecosystems makes nature legible by abstracting it from social and ecological contexts and making it subject to, and productive of, new market devices. In reducing the complexity of ecological dynamics to idealized categories TEEB is driven by economic ideas and idealism, and, in claiming to be a quantitative force for morality, is engaged in the production of practices designed to conform the ‘real’ to the virtual. By rendering a ‘valued’ nature legible for key audiences, TEEB has mobilized a critical mass of support including modellers, policy makers and bankers. We argue that TEEB's rhetoric of crisis and value aligns capitalism with a new kind of ecological modernization in which ‘the market’ and market devices serve as key mechanisms to conform the real and the virtual. Using the case of TEEB, and drawing on data collected at COP10, we illustrate the importance of international meetings as key points where idealized models of biodiversity protection emerge, circulate and are negotiated, and as sites where actors are aligned and articulated with these idealized models in ways that begin further processes of conforming the real with the virtual and the realization of ‘natural capital’.

Darrieus rotor aerodynamics

NASA Astrophysics Data System (ADS)

Klimas, P. C.

1982-05-01

A summary of the progress of modeling the aerodynamic effects on the blades of a Darrieus wind turbine is presented. Interference is discussed in terms of blade/blade wake interaction and improvements in single and multiple stream tube models, of vortex simulations of blades and their wakes, and a hybrid momentum/vortex code to combine fast computation time with interference-describing capabilities. An empirical model has been developed for treating the properties of dynamic stall such as airfoil geometry, Reynolds number, reduced frequency, angle-of-attack, and Mach number. Pitching circulation has been subjected to simulation as potential flow about a two-dimensional flat plate, along with applications of the concepts of virtual camber and virtual incidence, with a cambered airfoil operating in a rectilinear flowfield. Finally, a need to develop a loading model suitable for nonsymmetrical blade sections is indicated, as well as blade behavior in a dynamic, curvilinear regime.

Virtually-Enhanced Fluid Laboratories for Teaching Meteorology

NASA Astrophysics Data System (ADS)

Marshall, J.; Illari, L.

2015-12-01

The Weather in a Tank (WIAT) project aims to offer instructors a repertoire of rotating tank experiments, and a curriculum in fluid dynamics, to better assist students in learning how to move between phenomena in the real world and basic principles of rotating fluid dynamics which play a central role in determining the climate of the planet. Despite the increasing use of laboratory experiments in teaching meteorology, however, we are aware that many teachers and students do not have access to suitable apparatus and so cannot benefit from them. Here we describe a 'virtually-enhanced' laboratory that we hope could be very effective in getting across a flavor of the experiments and bring them to a wider audience. In the pedagogical spirit of WIAT we focus on how simple underlying principles, illustrated through laboratory experiments, shape the observed structure of the large-scale atmospheric circulation.

Spatial ability in secondary school students: intra-sex differences based on self-selection for physical education.

PubMed

Tlauka, Michael; Williams, Jennifer; Williamson, Paul

2008-08-01

Past research has demonstrated consistent sex differences with men typically outperforming women on tests of spatial ability. However, less is known about intra-sex effects. In the present study, two groups of female students (physical education and non-physical education secondary students) and two corresponding groups of male students explored a large-scale virtual shopping centre. In a battery of tasks, spatial knowledge of the shopping centre as well as mental rotation ability were tested. Additional variables considered were circulating testosterone levels, the ratio of 2D:4D digit length, and computer experience. The results revealed both sex and intra-sex differences in spatial ability. Variables related to virtual navigation and computer ability and experience were found to be the most powerful predictors of group membership. Our results suggest that in female and male secondary students, participation in physical education and spatial skill are related.

Parameter studies on the energy balance closure problem using large-eddy simulation

NASA Astrophysics Data System (ADS)

De Roo, Frederik; Banerjee, Tirtha; Mauder, Matthias

2017-04-01

The imbalance of the surface energy budget in eddy-covariance measurements is still a pending problem. A possible cause is the presence of land surface heterogeneity. Heterogeneities of the boundary layer scale or larger are most effective in influencing the boundary layer turbulence, and large-eddy simulations have shown that secondary circulations within the boundary layer can affect the surface energy budget. However, the precise influence of the surface characteristics on the energy imbalance and its partitioning is still unknown. To investigate the influence of surface variables on all the components of the flux budget under convective conditions, we set up a systematic parameter study by means of large-eddy simulation. For the study we use a virtual control volume approach, and we focus on idealized heterogeneity by considering spatially variable surface fluxes. The surface fluxes vary locally in intensity and these patches have different length scales. The main focus lies on heterogeneities of length scales of the kilometer scale and one decade smaller. For each simulation, virtual measurement towers are positioned at functionally different positions. We discriminate between the locally homogeneous towers, located within land use patches, with respect to the more heterogeneous towers, and find, among others, that the flux-divergence and the advection are strongly linearly related within each class. Furthermore, we seek correlators for the energy balance ratio and the energy residual in the simulations. Besides the expected correlation with measurable atmospheric quantities such as the friction velocity, boundary-layer depth and temperature and moisture gradients, we have also found an unexpected correlation with the temperature difference between sonic temperature and surface temperature. In additional simulations with a large number of virtual towers, we investigate higher order correlations, which can be linked to secondary circulations. In a companion presentation (EGU2017-2130) these correlations are investigated and confirmed with the help of micrometeorological measurements from the TERENO sites where the effects of landscape scale surface heterogeneities are deemed to be important.

Gyre formation within embayments of a large lake (Lake Geneva, Switzerland)

NASA Astrophysics Data System (ADS)

Razmi, A.; Barry, D.; Bouffard, D.; Le Dantec, N.; Lemmin, U.; Wuest, A.

2013-12-01

Numerical simulations were carried out to examine gyre formation within open, wide lacustrine embayments. The present study was motivated by observed differences in gyre formation within two open and wide embayments (located at Vidy and Morges in Lake Geneva, Switzerland). These two embayments are located within about 3 km of each other on the northern shore of Lake Geneva, and are subjected to similar pelagic currents. Vidy is deeper and has a greater aspect ratio than Morges. The flow field in the embayments was modeled using a previously validated 3D hydrodynamic model (Delft3D-FLOW). The model solved the Reynolds-Averaged Navier-Stokes equations, combined with a k-ɛ turbulence closure in σ (lakebed-following) coordinates. Our study focused on the influence of the embayment geometry on the (uniform) longshore (pelagic) current, specifically the occurrence and magnitude of circulation within the embayment. We built a set of numerical experiments using synthetic embayments, and systematically examined embayment geometry, thereby capturing the differences between the Vidy and Morges embayments. The numerical experiments considered single rectilinear embayments with different aspect ratios (i.e., 1-6), depth, shore-parallel flow rates, and embayment corner angle between 0°-50°. The circulation magnitude changes abruptly for an angle of about 40°. Embayments with angles greater than 40° have much greater circulation then those with lesser angles, other factors remaining the same. Of the factors considered (i.e., aspect ratio, offshore current velocity, corner angle, bottom slope, and viscosity), bottom slope and the viscosity have almost no impact on embayment circulation. For uniform offshore current patterns, gyres form in embayments with large aspect ratios (up to ~3). For the Vidy and Morges embayments, the results showed that gyre formation is more likely in Morges due to its smaller aspect ratio, a finding that is supported by field data gathered in drifter studies. For example, simultaneous drifter releases in 2011 showed parallel-to-shore currents in the Vidy embayment and a gyre in Morges. KEYWORDS: Hydrodynamics; Open Embayment; Flow Separation; Gyre; Topography; Lake Geneva.

Scaling and Numerical Model Evaluation of Snow-Cover Effects on the Generation and Modification of Daytime Mesoscale Circulations.

NASA Astrophysics Data System (ADS)

Segal, M.; Garratt, J. R.; Pielke, R. A.; Ye, Z.

1991-04-01

Consideration of the sensible heat flux characteristics over a snow surface suggests a significant diminution in the magnitude of the flux, compared to that over a snow-free surface under the same environmental conditions. Consequently, the existence of snow-covered mesoscale areas adjacent to snow-free areas produces horizontal thermal gradients in the lower atmosphere during the daytime, possibly resulting in a `snow breeze.' In addition, suppression of the daytime thermally induced upslope flow over snow-covered slopes is likely to occur. The present paper provides scaling and modeling evaluations of these situations, with quantification of the generated and modified circulations. These evaluations suggest that under ideal situations involved with uniform snow cover over large areas, particularly in late winter and early spring, a noticeable `snow breeze' is likely to develop. Additionally: suppression of the daytime thermally induced upslope flow is significant and may even result in a daytime drainage flow. The effects of bare ground patchiness in the snow cover on these circulations are also explored, both for flat terrain and slope-flow situations. A patchiness fraction greater than 0.5 is found to result in a noticeably reduced snow-breeze circulation, while a patchiness fraction of only 0.1 caused the simulated daytime drainage flow over slopes to he reversed.

Modeling the periodic stratification and gravitational circulation in San Francisco Bay, California

USGS Publications Warehouse

Cheng, Ralph T.; Casulli, Vincenzo

1996-01-01

A high resolution, three-dimensional (3-D) hydrodynamic numerical model is applied to San Francisco Bay, California to simulate the periodic tidal stratification caused by tidal straining and stirring and their long-term effects on gravitational circulation. The numerical model is formulated using fixed levels in the vertical and uniform computational mesh on horizontal planes. The governing conservation equations, the 3-D shallow water equations, are solved by a semi-implicit finite-difference scheme. Numerical simulations for estuarine flows in San Francisco Bay have been performed to reproduce the hydrodynamic properties of tides, tidal and residual currents, and salt transport. All simulations were carried out to cover at least 30 days, so that the spring-neap variance in the model results could be analyzed. High grid resolution used in the model permits the use of a simple turbulence closure scheme which has been shown to be sufficient to reproduce the tidal cyclic stratification and well-mixed conditions in the water column. Low-pass filtered 3-D time-series reveals the classic estuarine gravitational circulation with a surface layer flowing down-estuary and an up-estuary flow near the bottom. The intensity of the gravitational circulation depends upon the amount of freshwater inflow, the degree of stratification, and spring-neap tidal variations.

Influence of forced internal air circulation on airflow distribution and heat transfer in a gas double-dynamic solid-state fermentation bioreactor.

PubMed

Chen, Hongzhang; Qin, Lanzhi; Li, Hongqiang

2014-02-01

Internal air circulation affects the temperature field distribution in a gas double-dynamic solid-state fermentation bioreactor (GDSFB). To enhance heat transfer through strengthening internal air circulation in a GDSFB, we put an air distribution plate (ADP) into the bioreactor and studied the effects of forced internal air circulation on airflow, heat transfer, and cellulase activity of Trichoderma viride L3. Results showed that ADP could help form a steady and uniform airflow distribution, and with gas-guide tubes, air reversal was formed inside the bioreactor, thus resulting in a smaller temperature difference between medium and air by enhancing convective heat transfer inside the bioreactor. Using an ADP of 5.35 % aperture ratio caused a 1 °C decrease in the average temperature difference during the solid-state fermentation process of T. viride L3. Meanwhile, the cellulase activity of T. viride L3 increased by 13.5 %. The best heat-transfer effect was attained when using an ADP of 5.35 % aperture ratio and setting the fan power to 125 V (4.81 W) in the gas double-dynamic solid-state fermentation (GDSF) process. An option of suitable aperture ratio and fan power may be conducive to ADPs' industrial amplification.

Control of magnetohydrodynamic stability by phase space engineering of energetic ions in tokamak plasmas.

PubMed

Graves, J P; Chapman, I T; Coda, S; Lennholm, M; Albergante, M; Jucker, M

2012-01-10

Virtually collisionless magnetic mirror-trapped energetic ion populations often partially stabilize internally driven magnetohydrodynamic disturbances in the magnetosphere and in toroidal laboratory plasma devices such as the tokamak. This results in less frequent but dangerously enlarged plasma reorganization. Unique to the toroidal magnetic configuration are confined 'circulating' energetic particles that are not mirror trapped. Here we show that a newly discovered effect from hybrid kinetic-magnetohydrodynamic theory has been exploited in sophisticated phase space engineering techniques for controlling stability in the tokamak. These theoretical predictions have been confirmed, and the technique successfully applied in the Joint European Torus. Manipulation of auxiliary ion heating systems can create an asymmetry in the distribution of energetic circulating ions in the velocity orientated along magnetic field lines. We show the first experiments in which large sawtooth collapses have been controlled by this technique, and neoclassical tearing modes avoided, in high-performance reactor-relevant plasmas.

New Insights into Thyroid Hormone Action

PubMed Central

Mendoza, Arturo; Hollenberg, Anthony N.

2017-01-01

Thyroid hormones (TH) are endocrine messengers essential for normal development and function of virtually every vertebrate. The hypothalamic-pituitary-thyroid axis is exquisitely modulated to maintain nearly constant TH (T4 and T3) concentrations in circulation. However peripheral tissues and the CNS control the intracellular availability of TH, suggesting that circulating concentrations of TH are not fully representative of what each cell type sees. Indeed, recent work in the field has identified that TH transporters, deiodinases and thyroid hormone receptor coregulators can strongly control tissue-specific sensitivity to a set amount of TH. Furthermore, the mechanism by which the thyroid hormone receptors regulate target gene expression can vary by gene, tissue and cellular context. This review will highlight novel insights into the machinery that controls the cellular response to TH, which include unique signaling cascades. These findings shed new light into the pathophysiology of human diseases caused by abnormal TH signaling. PMID:28174093

Loss of endothelial barrier antigen immunoreactivity as a marker of Clostridium perfringens type D epsilon toxin-induced microvascular damage in rat brain.

PubMed

Finnie, J W; Manavis, J; Chidlow, G

2014-01-01

The epsilon toxin elaborated by Clostridium perfringens type D in the intestine of domestic livestock is principally responsible for the neurological disease produced after its absorption in excessive quantities into the systemic circulation. The fundamental basis of the cerebral damage induced by epsilon toxin appears to be microvascular injury with ensuing severe, diffuse vasogenic oedema. Endothelial barrier antigen (EBA), which is normally expressed by virtually all capillaries and venules in the rat brain, was used in this study as a marker of blood-brain barrier (BBB) integrity. After exposure to high levels of circulating epsilon toxin, there was substantial loss of EBA in many brain microvessels, attended by widespread plasma albumin extravasation. These results support microvascular injury and subsequent BBB breakdown as a key factor in the pathogenesis of epsilon toxin-induced neurological disease. Copyright © 2014 Elsevier Ltd. All rights reserved.

Parameter estimation of anisotropic Manning's n coefficient for advanced circulation (ADCIRC) modeling of estuarine river currents (lower St. Johns River)

NASA Astrophysics Data System (ADS)

Demissie, Henok K.; Bacopoulos, Peter

2017-05-01

A rich dataset of time- and space-varying velocity measurements for a macrotidal estuary was used in the development of a vector-based formulation of bottom roughness in the Advanced Circulation (ADCIRC) model. The updates to the parallel code of ADCIRC to include directionally based drag coefficient are briefly discussed in the paper, followed by an application of the data assimilation (nudging analysis) to the lower St. Johns River (northeastern Florida) for parameter estimation of anisotropic Manning's n coefficient. The method produced converging estimates of Manning's n values for ebb (0.0290) and flood (0.0219) when initialized with uniform and isotropic setting of 0.0200. Modeled currents, water levels and flows were improved at observation locations where data were assimilated as well as at monitoring locations where data were not assimilated, such that the method increases model skill locally and non-locally with regard to the data locations. The methodology is readily transferrable to other circulation/estuary models, given pre-developed quality mesh/grid and adequate data available for assimilation.

Plasma functionalization of powdery nanomaterials using porous filter electrode and sample circulation

NASA Astrophysics Data System (ADS)

Lee, Deuk Yeon; Choi, Jae Hong; Shin, Jung Chul; Jung, Man Ki; Song, Seok Kyun; Suh, Jung Ki; Lee, Chang Young

2018-06-01

Compared with wet processes, dry functionalization using plasma is fast, scalable, solvent-free, and thus presents a promising approach for grafting functional groups to powdery nanomaterials. Previous approaches, however, had difficulties in maintaining an intimate sample-plasma contact and achieving uniform functionalization. Here, we demonstrate a plasma reactor equipped with a porous filter electrode that increases both homogeneity and degree of functionalization by capturing and circulating powdery carbon nanotubes (CNTs) via vacuum and gas blowing. Spectroscopic measurements verify that treatment with O2/air plasma generates oxygen-containing groups on the surface of CNTs, with the degree of functionalization readily controlled by varying the circulation number. Gas sensors fabricated using the plasma-treated CNTs confirm alteration of molecular adsorption on the surface of CNTs. A sequential treatment with NH3 plasma following the oxidation pre-treatment results in the functionalization with nitrogen species of up to 3.2 wt%. Our approach requiring no organic solvents not only is cost-effective and environmentally friendly, but also serves as a versatile tool that applies to other powdery micro or nanoscale materials for controlled modification of their surfaces.

Anti-cyclonic circulation driven by the estuarine circulation in a gulf type ROFI

NASA Astrophysics Data System (ADS)

Fujiwara, T.; Sanford, L. P.; Nakatsuji, K.; Sugiyama, Y.

1997-08-01

Baroclinic residual circulation processes are examined in gulf type Regions Of Freshwater Influence (ROFIs), which have large rivers discharging into a rounded head wider than the Rossby internal deformation radius. Theoretical and observational investigations concentrate on Ise Bay, Japan, with supporting data from Osaka Bay and Tokyo Bay. Simplified analytical solutions are derived to describe the primary features of the circulation. Three dimensional residual current data collected using moored current meters and shipboard acoustic doppler current profilers (ADCPs), satellite imagery and density structure data observed using STDs, are presented for comparison to the theoretical predictions. There are three key points to understanding the resulting circulation in gulf type ROFIs. First, there are likely to be three distinct water masses: the river plume, a brackish upper layer, and a higher salinity lower layer. Second, baroclinic processes in gulf type ROFIs are influenced by the Earth's rotation at first order. Residual currents are quasi-geostrophic and potential vorticity is approximately conserved. Third, the combined effects of a classical longitudinal estuarine circulation and the Earth's rotation are both necessary to produce the resulting circulation. Anti-cyclonic vorticity is generated in the upper layer by the horizontal divergence associated with upward entrainment, which is part of the estuarine circulation. The interaction between anti-cyclonic vorticity and horizontal divergence results in two regions of qualitatively different circulation, with gyre-like circulation near the bay head and uniformly seaward anti-cyclonicly sheared flow further towards the mouth. The stagnation point separating the two regions is closer to (further away from) the bay head for stronger (weaker) horizontal divergence, respectively. The vorticity and spin-up time of this circulation are-(ƒ-ω 1)/2 and h/2w 0, respectively, where ƒ is the Coriolis parameter, ω 1 is the vorticity of the lower layer, h is the depth of the upper layer and w 0 is the upward entrainment velocity across the pycnocline. Under high discharge conditions the axis of the river plume proceeds in a right bounded direction, describing an inertial circle clearly seen in satellite images. Under low discharge conditions the river plume is deflected in a left bounded direction by the anti-cyclonic circulation of the upper layer.

A desirability-based multi objective approach for the virtual screening discovery of broad-spectrum anti-gastric cancer agents

PubMed Central

Sánchez-Rodríguez, Aminael; Tejera, Eduardo; Cruz-Monteagudo, Maykel; Borges, Fernanda; Cordeiro, M. Natália D. S.; Le-Thi-Thu, Huong; Pham-The, Hai

2018-01-01

Gastric cancer is the third leading cause of cancer-related mortality worldwide and despite advances in prevention, diagnosis and therapy, it is still regarded as a global health concern. The efficacy of the therapies for gastric cancer is limited by a poor response to currently available therapeutic regimens. One of the reasons that may explain these poor clinical outcomes is the highly heterogeneous nature of this disease. In this sense, it is essential to discover new molecular agents capable of targeting various gastric cancer subtypes simultaneously. Here, we present a multi-objective approach for the ligand-based virtual screening discovery of chemical compounds simultaneously active against the gastric cancer cell lines AGS, NCI-N87 and SNU-1. The proposed approach relays in a novel methodology based on the development of ensemble models for the bioactivity prediction against each individual gastric cancer cell line. The methodology includes the aggregation of one ensemble per cell line using a desirability-based algorithm into virtual screening protocols. Our research leads to the proposal of a multi-targeted virtual screening protocol able to achieve high enrichment of known chemicals with anti-gastric cancer activity. Specifically, our results indicate that, using the proposed protocol, it is possible to retrieve almost 20 more times multi-targeted compounds in the first 1% of the ranked list than what is expected from a uniform distribution of the active ones in the virtual screening database. More importantly, the proposed protocol attains an outstanding initial enrichment of known multi-targeted anti-gastric cancer agents. PMID:29420638

Pressure-gradient-driven nearshore circulation on a beach influenced by a large inlet-tidal shoal system

USGS Publications Warehouse

Shi, F.; Hanes, D.M.; Kirby, J.T.; Erikson, L.; Barnard, P.; Eshleman, J.

2011-01-01

The nearshore circulation induced by a focused pattern of surface gravity waves is studied at a beach adjacent to a major inlet with a large ebb tidal shoal. Using a coupled wave and wave-averaged nearshore circulation model, it is found that the nearshore circulation is significantly affected by the heterogeneous wave patterns caused by wave refraction over the ebb tidal shoal. The model is used to predict waves and currents during field experiments conducted near the mouth of San Francisco Bay and nearby Ocean Beach. The field measurements indicate strong spatial variations in current magnitude and direction and in wave height and direction along Ocean Beach and across the ebb tidal shoal. Numerical simulations suggest that wave refraction over the ebb tidal shoal causes wave focusing toward a narrow region at Ocean Beach. Due to the resulting spatial variation in nearshore wave height, wave-induced setup exhibits a strong alongshore nonuniformity, resulting in a dramatic change in the pressure field compared to a simulation with only tidal forcing. The analysis of momentum balances inside the surf zone shows that, under wave conditions with intensive wave focusing, the alongshore pressure gradient associated with alongshore nonuniform wave setup can be a dominant force driving circulation, inducing heterogeneous alongshore currents. Pressure-gradient- forced alongshore currents can exhibit flow reversals and flow convergence or divergence, in contrast to the uniform alongshore currents typically caused by tides or homogeneous waves.

Use of the omentum in chest-wall reconstruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fix, R.J.; Vasconez, L.O.

1989-10-01

Increased use of the omentum in chest-wall reconstruction has paralleled the refinement of anatomic knowledge and the development of safe mobilization techniques. Important anatomic points are the omental attachments to surrounding structures, the major blood supply from the left and right gastroepiploic vessels, and the collateral circulation via the gastroepiploic arch and Barkow's marginal artery. Mobilization of the omentum to the thorax involves division of its attachments to the transverse colon and separation from the greater curvature to fabricate a bipedicled flap. Most anterior chest wounds and virtually all mediastinal wounds can be covered with the omentum based on bothmore » sets of gastroepiploic vessels. The arc of transposition is increased when the omentum is based on a single pedicle, allowing coverage of virtually all chest-wall defects. The final method of increasing flap length involves division of the gastroepiploic arch and reliance on Barkow's marginal artery as collateral circulation to maintain flap viability. With regard to chest-wall reconstruction, we have included the omentum in the armamentarium of flaps used to cover mediastinal wounds. The omentum is our flap of choice for the reconstruction of most radiation injuries of the chest wall. The omentum may also be used to provide protection to visceral anastomoses, vascular conduits, and damaged structures in the chest, as well as to cover defects secondary to tumor excision or trauma. In brief, the omentum has proved to be a most dependable and versatile flap, particularly applicable to chest-wall reconstruction.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolotnikov, A. E., E-mail: bolotnik@bnl.gov; Ackley, K.; Camarda, G. S.

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe detectors coupled to a front-end readout application-specific integrated circuit (ASIC) for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6 × 6 × 15 mm{sup 3} detectors grouped into 3 × 3 sub-arrays of 2 × 2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We presentmore » the results from testing two fully assembled modules and readout electronics. The further enhancement of the arrays’ performance and reduction of their cost are possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolotnikov, A. E.; Ackley, K.; Camarda, G. S.

We developed a robust and low-cost array of virtual Frisch-grid CdZnTe (CZT) detectors coupled to a front-end readout ASIC for spectroscopy and imaging of gamma rays. The array operates as a self-reliant detector module. It is comprised of 36 close-packed 6x6x15 mm 3 detectors grouped into 3x3 sub-arrays of 2x2 detectors with the common cathodes. The front-end analog ASIC accommodates up to 36 anode and 9 cathode inputs. Several detector modules can be integrated into a single- or multi-layer unit operating as a Compton or a coded-aperture camera. We present the results from testing two fully assembled modules and readoutmore » electronics. The further enhancement of the arrays’ performance and reduction of their cost are made possible by using position-sensitive virtual Frisch-grid detectors, which allow for accurate corrections of the response of material non-uniformities caused by crystal defects.« less

Poor Man's Virtual Camera: Real-Time Simultaneous Matting and Camera Pose Estimation.

PubMed

Szentandrasi, Istvan; Dubska, Marketa; Zacharias, Michal; Herout, Adam

2016-03-18

Today's film and advertisement production heavily uses computer graphics combined with living actors by chromakeying. The matchmoving process typically takes a considerable manual effort. Semi-automatic matchmoving tools exist as well, but they still work offline and require manual check-up and correction. In this article, we propose an instant matchmoving solution for green screen. It uses a recent technique of planar uniform marker fields. Our technique can be used in indie and professional filmmaking as a cheap and ultramobile virtual camera, and for shot prototyping and storyboard creation. The matchmoving technique based on marker fields of shades of green is very computationally efficient: we developed and present in the article a mobile application running at 33 FPS. Our technique is thus available to anyone with a smartphone at low cost and with easy setup, opening space for new levels of filmmakers' creative expression.

Synchrotron X-ray diffraction investigations on strains in the oxide layer of an irradiated Zircaloy fuel cladding

NASA Astrophysics Data System (ADS)

Chollet, Mélanie; Valance, Stéphane; Abolhassani, Sousan; Stein, Gene; Grolimund, Daniel; Martin, Matthias; Bertsch, Johannes

2017-05-01

For the first time the microstructure of the oxide layer of a Zircaloy-2 cladding after 9 cycles of irradiation in a boiling water reactor has been analyzed with synchrotron micro-X-ray diffraction. Crystallographic strains of the monoclinic and to some extent of the tetragonal ZrO2 are depicted through the thick oxide layer. Thin layers of sub-oxide at the oxide-metal interface as found for autoclave-tested samples and described in the literature, have not been observed in this material maybe resulting from irradiation damage. Shifts of selected diffraction peaks of the monoclinic oxide show that the uniform strain produced during oxidation is orientated in the lattice and displays variations along the oxide layer. Diffraction peaks and their shifts from families of diffracting planes could be translated into a virtual tensor. This virtual tensor exhibits changes through the oxide layer passing by tensile or compressive components.

Multianode cylindrical proportional counter for high count rates

DOEpatents

Hanson, J.A.; Kopp, M.K.

1980-05-23

A cylindrical, multiple-anode proportional counter is provided for counting of low-energy photons (< 60 keV) at count rates of greater than 10/sup 5/ counts/sec. A gas-filled proportional counter cylinder forming an outer cathode is provided with a central coaxially disposed inner cathode and a plurality of anode wires disposed in a cylindrical array in coaxial alignment with and between the inner and outer cathodes to form a virtual cylindrical anode coaxial with the inner and outer cathodes. The virtual cylindrical anode configuration improves the electron drift velocity by providing a more uniform field strength throughout the counter gas volume, thus decreasing the electron collection time following the detection of an ionizing event. This avoids pulse pile-up and coincidence losses at these high count rates. Conventional RC position encoding detection circuitry may be employed to extract the spatial information from the counter anodes.

Multianode cylindrical proportional counter for high count rates

DOEpatents

Hanson, James A.; Kopp, Manfred K.

1981-01-01

A cylindrical, multiple-anode proportional counter is provided for counting of low-energy photons (<60 keV) at count rates of greater than 10.sup.5 counts/sec. A gas-filled proportional counter cylinder forming an outer cathode is provided with a central coaxially disposed inner cathode and a plurality of anode wires disposed in a cylindrical array in coaxial alignment with and between the inner and outer cathodes to form a virtual cylindrical anode coaxial with the inner and outer cathodes. The virtual cylindrical anode configuration improves the electron drift velocity by providing a more uniform field strength throughout the counter gas volume, thus decreasing the electron collection time following the detection of an ionizing event. This avoids pulse pile-up and coincidence losses at these high count rates. Conventional RC position encoding detection circuitry may be employed to extract the spatial information from the counter anodes.

Zero potential vorticity envelopes for the zonal-mean velocity of the Venus/Titan atmospheres

NASA Technical Reports Server (NTRS)

Allison, Michael; Del Genio, Anthony D.; Zhou, Wei

1994-01-01

The diagnostic analysis of numerical simulations of the Venus/Titan wind regime reveals an overlooked constraint upon the latitudinal structure of their zonal-mean angular momentum. The numerical experiments, as well as the limited planetary observations, are approximately consistent with the hypothesis that within the latitudes bounded by the wind maxima the total Ertel potential vorticity associated with the zonal-mean motion is approximately well mixed with respect to the neutral equatorial value for a stable circulation. The implied latitudinal profile of angular momentum is of the form M equal to or less than M(sub e)(cos lambda)(exp 2/Ri), where lambda is the latitude and Ri the local Richardson number, generally intermediate between the two extremes of uniform angular momentum (Ri approaches infinity) and uniform angular velocity (Ri = 1). The full range of angular momentum profile variation appears to be realized within the observed meridional - vertical structure of the Venus atmosphere, at least crudely approaching the implied relationship between stratification and zonal velocity there. While not itself indicative of a particular eddy mechanism or specific to atmospheric superrotation, the zero potential vorticity (ZPV) constraint represents a limiting bound for the eddy - mean flow adjustment of a neutrally stable baroclinic circulation and may be usefully applied to the diagnostic analysis of future remote sounding and in situ measurements from planetary spacecraft.

System for producing a uniform rubble bed for in situ processes

DOEpatents

Galloway, T.R.

1983-07-05

A method and a cutter are disclosed for producing a large cavity filled with a uniform bed of rubblized oil shale or other material, for in situ processing. A raise drill head has a hollow body with a generally circular base and sloping upper surface. A hollow shaft extends from the hollow body. Cutter teeth are mounted on the upper surface of the body and relatively small holes are formed in the body between the cutter teeth. Relatively large peripheral flutes around the body allow material to drop below the drill head. A pilot hole is drilled into the oil shale deposit. The pilot hole is reamed into a large diameter hole by means of a large diameter raise drill head or cutter to produce a cavity filled with rubble. A flushing fluid, such as air, is circulated through the pilot hole during the reaming operation to remove fines through the raise drill, thereby removing sufficient material to create sufficient void space, and allowing the larger particles to fill the cavity and provide a uniform bed of rubblized oil shale. 4 figs.

Rotating-fluid experiments with an atmospheric general circulation model

NASA Technical Reports Server (NTRS)

Geisler, J. E.; Pitcher, E. J.; Malone, R. C.

1983-01-01

In order to determine features of rotating fluid flow that are dependent on the geometry, rotating annulus-type experiments are carried out with a numerical model in spherical coordinates. Rather than constructing and testing a model expressly for this purpose, it is found expedient to modify an existing general circulation model of the atmosphere by removing the model physics and replacing the lower boundary with a uniform surface. A regime diagram derived from these model experiments is presented; its major features are interpreted and contrasted with the major features of rotating annulus regime diagrams. Within the wave regime, a narrow region is found where one or two zonal wave numbers are dominant. The results reveal no upper symmetric regime; wave activity at low rotation rates is thought to be maintained by barotropic rather than baroclinic processes.

Technical challenges in the isolation and analysis of circulating tumor cells.

PubMed

van der Toom, Emma E; Verdone, James E; Gorin, Michael A; Pienta, Kenneth J

2016-09-20

Increasing evidence suggests that cancer cells display dynamic molecular changes in response to systemic therapy. Circulating tumor cells (CTCs) in the peripheral blood represent a readily available source of cancer cells with which to measure this dynamic process. To date, a large number of strategies to isolate and characterize CTCs have been described. These techniques, however, each have unique limitations in their ability to sensitively and specifically detect these rare cells. In this review we focus on the technical limitations and pitfalls of the most common CTC isolation and detection strategies. Additionally, we emphasize the difficulties in correctly classifying rare cells as CTCs using common biomarkers. As for assays developed in the future, the first step must be a uniform and clear definition of the criteria for assigning an object as a CTC based on disease-specific biomarkers.

STUDIES ON TRANSMISSIBLE LYMPHOID LEUCEMIA OF MICE.

PubMed

Furth, J; Strumia, M

1931-04-30

Lymphoid leucemia of the mouse is readily transmitted by intravenous inoculations. The majority of the mice inoculated successfully develop leucemic, a smaller number of them, aleucemic lymphadenosis. The data presented favor the view that leucemic and aleucemic lymphadenosis are essentially the same condition. Leucemia produced by transmission is preceded by an aleucemic stage, in which the lymph nodes and the spleen are uniformly enlarged, and the white blood count and the percentage of lymphocytes are within the normal range but immature lymphocytes are numerous in the circulating blood. Young as well as old mice may develop leucemia if leucotic material enters their circulation. Studies of transmissible leucemia favor the view that leucemia of mammals is a neoplastic disease. The basic problem of leucemia would seem to be determination of the factors that bring about a malignant transformation of lymphoid cells.

STUDIES ON TRANSMISSIBLE LYMPHOID LEUCEMIA OF MICE

PubMed Central

Furth, J.; Strumia, M.

1931-01-01

Lymphoid leucemia of the mouse is readily transmitted by intravenous inoculations. The majority of the mice inoculated successfully develop leucemic, a smaller number of them, aleucemic lymphadenosis. The data presented favor the view that leucemic and aleucemic lymphadenosis are essentially the same condition. Leucemia produced by transmission is preceded by an aleucemic stage, in which the lymph nodes and the spleen are uniformly enlarged, and the white blood count and the percentage of lymphocytes are within the normal range but immature lymphocytes are numerous in the circulating blood. Young as well as old mice may develop leucemia if leucotic material enters their circulation. Studies of transmissible leucemia favor the view that leucemia of mammals is a neoplastic disease. The basic problem of leucemia would seem to be determination of the factors that bring about a malignant transformation of lymphoid cells. PMID:19869876

Development of the Circulation Control Flow Scheme Used in the NTF Semi-Span FAST-MAC Model

NASA Technical Reports Server (NTRS)

Jones, Gregory S.; Milholen, William E., II; Chan, David T.; Allan, Brian G.; Goodliff, Scott L.; Melton, Latunia P.; Anders, Scott G.; Carter, Melissa B.; Capone, Francis J.

2013-01-01

The application of a circulation control system for high Reynolds numbers was experimentally validated with the Fundamental Aerodynamic Subsonic Transonic Modular Active Control semi-span model in the NASA Langley National Transonic Facility. This model utilized four independent flow paths to modify the lift and thrust performance of a representative advanced transport type of wing. The design of the internal flow paths highlights the challenges associated with high Reynolds number testing in a cryogenic pressurized wind tunnel. Weight flow boundaries for the air delivery system were identified at mildly cryogenic conditions ranging from 0.1 to 10 lbm/sec. Results from the test verified system performance and identified solutions associated with the weight-flow metering system that are linked to internal perforated plates used to achieve flow uniformity at the jet exit.

Scleroderma Related Lung Disease: Is There a Pathogenic Role for Adipokines?

PubMed Central

Haley, Shannon; Shah, Dilip; Romero, Freddy; Summer, Ross

2013-01-01

Scleroderma is a systemic autoimmune disease of unknown etiology whose hallmark features include endothelial cell dysfunction, fibroblast proliferation and immune dysregulation. Although virtually any organ can be pathologically involved in scleroderma, lung complications including interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) are the leading cause of death in patients with this condition. Currently, the molecular mechanisms leading to development of scleroderma-related lung disease are poorly understood; however, the systemic nature of this condition has led many to implicate circulating factors in the pathogenesis of some of its organ impairment. In this article, we focus on a new class of circulating factors derived from adipose-tissue called adipokines, which are known to be altered in scleroderma. Recently, the adipokines adiponectin and leptin have been found to regulate biological activities in endothelial, fibroblast and immune cell types in lung and in many other tissues. The pleiotropic nature of these circulating factors and their functional activity on many cell types implicated in the pathogenesis of ILD and PAH suggest these hormones may play a mechanistic role in the onset and/or progression of scleroderma-related lung diseases. PMID:24173692

Cell–specific Variation in E-selectin Ligand Expression Among Human Peripheral Blood Mononuclear Cells: Implications for Immunosurveillance and Pathobiology

PubMed Central

Silva, Mariana; Fung, Ronald Kam Fai; Donnelly, Conor Brian; Videira, Paula Alexandra; Sackstein, Robert

2017-01-01

Both host defense and immunopathology are shaped by the ordered recruitment of circulating leukocytes to affected sites, a process initiated by binding of blood-borne cells to E-selectin displayed at target endothelial beds. Accordingly, knowledge of the expression and function of leukocyte E-selectin ligands is key to understanding the tempo and specificity of immunoreactivity. Here, we performed E-selectin adherence assays under hemodynamic flow conditions coupled with flow cytometry and western blot analysis to elucidate the function and structural biology of glycoprotein E-selectin ligands expressed on human peripheral blood mononuclear cells (PBMCs). Circulating monocytes uniformly express high levels of the canonical E-selectin binding determinant sLeX and display markedly greater adhesive interactions with E-selectin than do circulating lymphocytes, which exhibit variable E-selectin binding among CD4+ and CD8+ T-cells but no binding by B-cells. Monocytes prominently present sLeX decorations on an array of protein scaffolds including PSGL-1, CD43, and CD44 (rendering the E-selectin ligands CLA, CD43E, and HCELL, respectively), and B-cells altogether lack E-selectin ligands. Quantitative PCR gene expression studies of glycosyltransferases that regulate display of sLeX reveal high transcript levels among circulating monocytes and low levels among circulating B-cells, and, commensurately, cell surface α(1,3)-fucosylation reveals that acceptor sialyllactosaminyl glycans convertible into sLeX are abundantly expressed on human monocytes yet are relatively deficient on B-cells. Collectively, these findings unveil distinct cell-specific patterns of E-selectin ligand expression among human PBMCs, indicating that circulating monocytes are specialized to engage E-selectin and providing key insights into the molecular effectors mediating recruitment of these cells at inflammatory sites. PMID:28330896

The Regional Water Cycle and Water Ice Clouds in the Tharsis - Valles Marineris System

NASA Astrophysics Data System (ADS)

Leung, C. W. S.; Rafkin, S. C.

2017-12-01

The regional atmospheric circulation on Mars is highly influenced by local topographic gradients. Terrain-following air parcels forced along the slopes of the major Tharsis volcanoes and the steep canyon walls of Valles Marineris significantly impact the local water vapor concentration and the associated conditions for cloud formation. Using a non-hydrostatic mesoscale atmospheric model with aerosol & cloud microphysics, we investigate the meteorological conditions for water ice cloud formation in the coupled Tharsis - Valles Marineris system near the aphelion season. The usage of a limited area regional model ensures that topographic slopes are well resolved compared to the typical resolutions of a global-coverage general circulation model. The effects of shadowing and slope angle geometries on the energy budget is also taken into account. Diurnal slope winds in complex terrains are typically characterized by the reversal of wind direction twice per sol: upslope during the day, and downslope at night. However, our simulation results of the regional circulation and diurnal water cycle indicate substantial asymmetries in the day-night circulation. The convergence of moist air masses enters Valles Marineris via easterly flows, whereas dry air sweep across the plateau of the canyon system from the south towards the north. We emphasize the non-uniform vertical distribution of water vapor in our model results. Water vapor mixing ratios in the lower planetary boundary layer may be factors greater than the mixing ratio aloft. Water ice clouds are important contributors to the climatic forcing on Mars, and their effects on the mesoscale circulations in the Tharsis - Valles Marineris region significantly contribute to the regional perturbations in the large-scale global atmospheric circulation.

RTS2: a powerful robotic observatory manager

NASA Astrophysics Data System (ADS)

Kubánek, Petr; Jelínek, Martin; Vítek, Stanislav; de Ugarte Postigo, Antonio; Nekola, Martin; French, John

2006-06-01

RTS2, or Remote Telescope System, 2nd Version, is an integrated package for remote telescope control under the Linux operating system. It is designed to run in fully autonomous mode, picking targets from a database table, storing image meta data to the database, processing images and storing their WCS coordinates in the database and offering Virtual-Observatory enabled access to them. It is currently running on various telescope setups world-wide. For control of devices from various manufacturers we developed an abstract device layer, enabling control of all possible combinations of mounts, CCDs, photometers, roof and cupola controllers. We describe the evolution of RTS2 from Python-based RTS to C and later C++ based RTS2, focusing on the problems we faced during development. The internal structure of RTS2, focusing on object layering, which is used to uniformly control various devices and provides uniform reporting layer, is also discussed.

The Mass and Angular Momentum Balance of the Zonally-Averaged Global Circulation.

DTIC Science & Technology

1981-01-01

2 2SFSf F SO~ ABSTRACT (0m-l n oerse~e side Ht moeoeei md fdeutly’ by Week now"*ee Li ATTACHED hO u 47 EDI TIo OP 1 NOV6 Ies OBSOLETE UNCLASS 82 09 28...eddies, and transient circulat.@ns, respec tively. rigeree 12 and 13 displa the vertical sad meridional distribution of relat’.ve angular momentum trass...the transient component is the dominant mode of angular momentum transport in January. It is poleward at virtually all latitudes in each hemisphere

Combustion and NOx emissions in deep-air-staging combustion of char in a circulating fluidized bed

NASA Astrophysics Data System (ADS)

Gong, Zhiqiang; Wang, Zhentong; Wang, Lei; Du, Aixun

2017-10-01

Combustion and NOx emissions in deep-air-staging (with higher level secondary air (SA) injection) combustion of char have been investigated in a CFB test rig. A good fluidized condition and uniform temperature distribution can be achieved with injection of higher level SA. NOx emission decreases with injection of higher level SA and the reduction effect is more obvious at higher temperature. NOx emission decreases with combustion temperature increasing for char combustion.

Rapid solution casting under vacuum of very thick sheets of a segmented polyurethane elastomer

NASA Technical Reports Server (NTRS)

Cuddihy, E. F.; Moacanin, J.

1981-01-01

A technique has been developed for rapidly casting from solution under vacuum smooth, bubble-free, clear-white and uniformly thick (about 0.20 cm) sheets of a segmented polyurethane elastomer. The casting is carried out from dimethylformamide solutions inside temperature-controlled air-circulated ovens in order to minimize the establishment of thermal gradients throughout the casting solution. The technique produces quality sheets in 9 days, compared with 40-45 days for an inferior film produced in open pans.

Lamp system for uniform semiconductor wafer heating

DOEpatents

Zapata, Luis E.; Hackel, Lloyd

2001-01-01

A lamp system with a very soft high-intensity output is provided over a large area by water cooling a long-arc lamp inside a diffuse reflector of polytetrafluorethylene (PTFE) and titanium dioxide (TiO.sub.2) white pigment. The water is kept clean and pure by a one micron particulate filter and an activated charcoal/ultraviolet irradiation system that circulates and de-ionizes and biologically sterilizes the coolant water at all times, even when the long-arc lamp is off.

Timeslice experiments for understanding regional climate projections: applications to the tropical hydrological cycle and European winter circulation

NASA Astrophysics Data System (ADS)

Chadwick, Robin; Douville, Hervé; Skinner, Christopher B.

2017-11-01

A set of atmosphere-only timeslice experiments are described, designed to examine the processes that cause regional climate change and inter-model uncertainty in coupled climate model responses to CO_2 forcing. The timeslice experiments are able to reproduce the pattern of regional climate change in the coupled models, and are applied here to two cases where inter-model uncertainty in future projections is large: the tropical hydrological cycle, and European winter circulation. In tropical forest regions, the plant physiological effect is the largest cause of hydrological cycle change in the two models that represent this process. This suggests that the CMIP5 ensemble mean may be underestimating the magnitude of water cycle change in these regions, due to the inclusion of models without the plant effect. SST pattern change is the dominant cause of precipitation and circulation change over the tropical oceans, and also appears to contribute to inter-model uncertainty in precipitation change over tropical land regions. Over Europe and the North Atlantic, uniform SST increases drive a poleward shift of the storm-track. However this does not consistently translate into an overall polewards storm-track shift, due to large circulation responses to SST pattern change, which varies across the models. Coupled model SST biases influence regional rainfall projections in regions such as the Maritime Continent, and so projections in these regions should be treated with caution.

Postbuckling of magneto-electro-elastic CNT-MT composite nanotubes resting on a nonlinear elastic medium in a non-uniform thermal environment

NASA Astrophysics Data System (ADS)

Kamali, M.; Shamsi, M.; Saidi, A. R.

2018-03-01

As a first endeavor, the effect of nonlinear elastic foundation on the postbuckling behavior of smart magneto-electro-elastic (MEE) composite nanotubes is investigated. The composite nanotube is affected by a non-uniform thermal environment. A typical MEE composite nanotube consists of microtubules (MTs) and carbon nanotubes (CNTs) with a MEE cylindrical nanoshell for smart control. It is assumed that the nanoscale layers of the system are coupled by a polymer matrix or filament network depending on the application. In addition to thermal loads, magneto-electro-mechanical loads are applied to the composite nanostructure. Length scale effects are taken into account using the nonlocal elasticity theory. The principle of virtual work and von Karman's relations are used to derive the nonlinear governing differential equations of MEE CNT-MT nanotubes. Using Galerkin's method, nonlinear critical buckling loads are determined. Various types of non-uniform temperature distribution in the radial direction are considered. Finally, the effects of various parameters such as the nonlinear constant of elastic medium, thermal loading factor and small scale coefficient on the postbuckling of MEE CNT-MT nanotubes are studied.

Fabrication of highly uniform and porous MgF2 anti-reflective coatings by polymer-based sol-gel processing on large-area glass substrates.

PubMed

Raut, Hemant Kumar; Dinachali, Saman Safari; Ansah-Antwi, Kwadwo Konadu; Ganesh, V Anand; Ramakrishna, Seeram

2013-12-20

Despite recent progress in the fabrication of magnesium fluoride (MgF2) anti-reflective coatings (ARCs), simple, effective and scalable sol-gel fabrication of MgF2 ARCs for large-area glass substrates has prospective application in various optoelectronic devices. In this paper, a polymer-based sol-gel route was devised to fabricate highly uniform and porous MgF2 ARCs on large-area glass substrates. A sol-gel precursor made of polyvinyl acetate and magnesium trifluoroacetate assisted in the formation of uniformly mesoporous MgF2 ARCs on glass substrates, leading to the attainment of a refractive index of ~1.23. Systematic optimization of the thickness of the ARC in the sub-wavelength regime led to achieving ~99.4% transmittance in the case of the porous MgF2 ARC glass. Precise control of the thickness of porous MgF2 ARC glass also resulted in a mere ~0.1% reflection, virtually eliminating reflection off the glass surface at the target wavelength. Further manipulation of the thickness of the ARC on either side of the glass substrate led to the fabrication of relatively broadband, porous MgF2 ARC glass.

Dynamic provisioning of local and remote compute resources with OpenStack

NASA Astrophysics Data System (ADS)

Giffels, M.; Hauth, T.; Polgart, F.; Quast, G.

2015-12-01

Modern high-energy physics experiments rely on the extensive usage of computing resources, both for the reconstruction of measured events as well as for Monte-Carlo simulation. The Institut fur Experimentelle Kernphysik (EKP) at KIT is participating in both the CMS and Belle experiments with computing and storage resources. In the upcoming years, these requirements are expected to increase due to growing amount of recorded data and the rise in complexity of the simulated events. It is therefore essential to increase the available computing capabilities by tapping into all resource pools. At the EKP institute, powerful desktop machines are available to users. Due to the multi-core nature of modern CPUs, vast amounts of CPU time are not utilized by common desktop usage patterns. Other important providers of compute capabilities are classical HPC data centers at universities or national research centers. Due to the shared nature of these installations, the standardized software stack required by HEP applications cannot be installed. A viable way to overcome this constraint and offer a standardized software environment in a transparent manner is the usage of virtualization technologies. The OpenStack project has become a widely adopted solution to virtualize hardware and offer additional services like storage and virtual machine management. This contribution will report on the incorporation of the institute's desktop machines into a private OpenStack Cloud. The additional compute resources provisioned via the virtual machines have been used for Monte-Carlo simulation and data analysis. Furthermore, a concept to integrate shared, remote HPC centers into regular HEP job workflows will be presented. In this approach, local and remote resources are merged to form a uniform, virtual compute cluster with a single point-of-entry for the user. Evaluations of the performance and stability of this setup and operational experiences will be discussed.

The effects of atmospheric cloud radiative forcing on climate

NASA Technical Reports Server (NTRS)

Randall, David A.

1989-01-01

In order to isolate the effects of atmospheric cloud radiative forcing (ACRF) on climate, the general circulation of an ocean-covered earth called 'Seaworld' was simulated using the Colorado State University GCM. Most current climate models, however, do not include an interactive ocean. The key simplifications in 'Seaworld' are the fixed boundary temperature with no land points, the lack of mountains and the zonal uniformity of the boundary conditions. Two 90-day 'perpetual July' simulations were performed and analyzed the last sixty days of each. The first run included all the model's physical parameterizations, while the second omitted the effects of clouds in both the solar and terrestrial radiation parameterizations. Fixed and identical boundary temperatures were set for the two runs, and resulted in differences revealing the direct and indirect effects of the ACRF on the large-scale circulation and the parameterized hydrologic processes.

Comparison of Two Grid Refinement Approaches for High Resolution Regional Climate Modeling: MPAS vs WRF

NASA Astrophysics Data System (ADS)

Leung, L.; Hagos, S. M.; Rauscher, S.; Ringler, T.

2012-12-01

This study compares two grid refinement approaches using global variable resolution model and nesting for high-resolution regional climate modeling. The global variable resolution model, Model for Prediction Across Scales (MPAS), and the limited area model, Weather Research and Forecasting (WRF) model, are compared in an idealized aqua-planet context with a focus on the spatial and temporal characteristics of tropical precipitation simulated by the models using the same physics package from the Community Atmosphere Model (CAM4). For MPAS, simulations have been performed with a quasi-uniform resolution global domain at coarse (1 degree) and high (0.25 degree) resolution, and a variable resolution domain with a high-resolution region at 0.25 degree configured inside a coarse resolution global domain at 1 degree resolution. Similarly, WRF has been configured to run on a coarse (1 degree) and high (0.25 degree) resolution tropical channel domain as well as a nested domain with a high-resolution region at 0.25 degree nested two-way inside the coarse resolution (1 degree) tropical channel. The variable resolution or nested simulations are compared against the high-resolution simulations that serve as virtual reality. Both MPAS and WRF simulate 20-day Kelvin waves propagating through the high-resolution domains fairly unaffected by the change in resolution. In addition, both models respond to increased resolution with enhanced precipitation. Grid refinement induces zonal asymmetry in precipitation (heating), accompanied by zonal anomalous Walker like circulations and standing Rossby wave signals. However, there are important differences between the anomalous patterns in MPAS and WRF due to differences in the grid refinement approaches and sensitivity of model physics to grid resolution. This study highlights the need for "scale aware" parameterizations in variable resolution and nested regional models.

Impacts of Interannual Ocean Circulation Variability on Japanese Eel Larval Migration in the Western North Pacific Ocean.

PubMed

Chang, Yu-Lin; Sheng, Jinyu; Ohashi, Kyoko; Béguer-Pon, Mélanie; Miyazawa, Yasumasa

2015-01-01

The Japanese eel larvae hatch near the West Mariana Ridge seamount chain and travel through the North Equatorial Current (NEC), the Kuroshio, and the Subtropical Countercurrent (STCC) region during their shoreward migration toward East Asia. The interannual variability of circulation over the subtropical and tropical regions of the western North Pacific Ocean is affected by the Philippines-Taiwan Oscillation (PTO). This study examines the effect of the PTO on the Japanese eel larval migration routes using a three-dimensional (3D) particle tracking method, including vertical and horizontal swimming behavior. The 3D circulation and hydrography used for particle tracking are from the ocean circulation reanalysis produced by the Japan Coastal Ocean Predictability Experiment 2 (JCOPE2). Our results demonstrate that bifurcation of the NEC and the strength and spatial variation of the Kuroshio affect the distribution and migration of eel larvae. During the positive phase of PTO, more virtual eels ("v-eels") can enter the Kuroshio to reach the south coast of Japan and more v-eels reach the South China Sea through the Luzon Strait; the stronger and more offshore swing of the Kuroshio in the East China Sea leads to fewer eels entering the East China Sea and the onshore movement of the Kuroshio to the south of Japan brings the eels closer to the Japanese coast. Significant differences in eel migration routes and distributions regulated by ocean circulation in different PTO phases can also affect the otolith increment. The estimated otolith increment suggests that eel age tends to be underestimated after six months of simulation due to the cooler lower layer temperature. Underestimation is more significant in the positive PTO years due to the wide distribution in higher latitudes than in the negative PTO years.

Porous electrode apparatus for electrodeposition of detailed metal structures or microelectronic interconnections

DOEpatents

Griffiths, Stewart K.; Nilson, Robert H.; Hruby, Jill M.

2002-01-01

An apparatus and procedure for performing microfabrication of detailed metal structures by electroforming metal deposits within small cavities. Two primary areas of application are: the LIGA process which manufactures complex three-dimensional metal parts and the damascene process used for electroplating line and via interconnections of microelectronic devices. A porous electrode held in contact or in close proximity with a plating substrate or mold top to ensure one-dimensional and uniform current flow into all mold cavities is used. Electrolyte is pumped over the exposed surface of the porous electrode to ensure uniform ion concentrations at this external surface. The porous electrode prevents electrolyte circulation within individual mold cavities, avoiding preferential enhancement of ion transport in cavities having favorable geometries. Both current flow and ion transport are one-dimensional and identical in all mold cavities, so all metal deposits grow at the same rate eliminating nonuniformities of the prior art.

Optimized Baking of the DIII-D Vessel

DOE Office of Scientific and Technical Information (OSTI.GOV)

P.M. Anderson; A.G. Kellman

The DIII-D tokamak vacuum vessel baking system is used to heat the vessel walls and internal hardware to an average temperature of 350 C to allow rapid conditioning of the vacuum surfaces. The system combines inductive heating and a circulating hot air system to provide rapid heating with temperature uniformity required by stress considerations. In recent years, the time to reach 350 C had increased from 9 hrs to 14 hrs. To understand and remedy this sluggish heating rate, an evaluation of the baking system was recently performed. The evaluation indicated that the mass of additional in-vessel hardware (50% increasemore » in mass) was primarily responsible. This paper reports on this analysis and the results of the addition of an electric air heater and procedural changes that have been implemented. Preliminary results indicate that the time to 350 C has been decreased to 4.5 hours and the temperature uniformity has improved.« less

A breeze-driven current on sloped littoral waters

NASA Astrophysics Data System (ADS)

Tohidi, A.; Jamali, M.

2017-12-01

Various natural phenomena, e. g. uniform/non-uniform solar radiation and diurnal cycles, affect water circulation patterns through aquatic canopies, that is (usually shallow) shorelines of the rivers, lakes, and lagoons. Amongst these factors is vegetation that, plays a crucial role in conserving and dispersing the nutrients, oxygen, temperature, and generally regulating the life and interactions of organisms with each other (ecology) in aquatic canopies. So far, however, very little attention has been paid to the effects of very low, breeze-like, winds over the water surface in these vegetated regions. In this exploratory study, the evolution of a breeze-driven gravity current traveling up the slope towards the shorelines is shown, experimentally. The flow is characterized using Particle Image Velocimetry (PIV) technique. In addition, a detailed dimensional analysis of the parameter space of the phenomenon is conducted. The results strongly corroborate the experimental observations.

Cauchy integral method for two-dimensional solidification interface shapes

NASA Astrophysics Data System (ADS)

Siegel, R.; Sosoka, D. J.

1982-07-01

A method is developed to determine the shape of steady state solidification interfaces formed when liquid above its freezing point circulates over a cold surface. The solidification interface, which is at uniform temperature, will form in a shape such that the non-uniform energy convected to it is locally balanced by conduction into the solid. The interface shape is of interest relative to the crystal structure formed during solidification; regulating the crystal structure has application in casting naturally strengthened metallic composites. The results also pertain to phase-change energy storage devices, where the solidified configuration and overall heat transfer are needed. The analysis uses a conformal mapping technique to relate the desired interface coordinates to the components of the temperature gradient at the interface. These components are unknown because the interface shape is unknown. A Cauchy integral formulation provides a second relation involving the components, and a simultaneous solution yields the interface shape.

Anisotropy of MHD Turbulence at Low Magnetic Reynolds Number

NASA Technical Reports Server (NTRS)

Zikanov, O.; Vorobev, A.; Thess, A.; Davidson, P. A.; Knaepen, B.

2004-01-01

Turbulent fluctuations in MHD flows are known to become dimensionally anisotropic under the action of a sufficiently strong magnetic field. We consider the technologically relevant case of low magnetic Reynolds number and apply the method of DNS of forced flow in a periodic box to generate velocity fields. The analysis based on different anisotropy characteristics shows that the dimensional anisotropy is virtually scale-independent. We also find that, except for the case of very strong magnetic field, the flow is componentally isotropic. Its kinetic energy is practically uniformly distributed among the velocity components.

MEGA X: Molecular Evolutionary Genetics Analysis across Computing Platforms.

PubMed

Kumar, Sudhir; Stecher, Glen; Li, Michael; Knyaz, Christina; Tamura, Koichiro

2018-06-01

The Molecular Evolutionary Genetics Analysis (Mega) software implements many analytical methods and tools for phylogenomics and phylomedicine. Here, we report a transformation of Mega to enable cross-platform use on Microsoft Windows and Linux operating systems. Mega X does not require virtualization or emulation software and provides a uniform user experience across platforms. Mega X has additionally been upgraded to use multiple computing cores for many molecular evolutionary analyses. Mega X is available in two interfaces (graphical and command line) and can be downloaded from www.megasoftware.net free of charge.

Flame Resistant Foam

NASA Technical Reports Server (NTRS)

1984-01-01

Solimide manufactured by Imi-Tech Corporation, is a lightweight fire resistant material produced under a manufacturing process that allows it to be uniformly foamed. Can be produced in a variety of densities and structural configurations and remains resilient under exposure to temperatures ranging from minus 300 to plus 500 degrees Fahrenheit. Is resistant to open flame and generates virtually no smoke or toxic by-products. Used in aircraft for its superior damping characteristics, lighter weight and fire barrier properties, it's also applicable to ships and surface transportation systems such as transit cars, trains, buses and automobiles.

STEAM GENERATOR FOR GAS COOLED NUCLEAR REACTORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1960-03-14

A steam generator for a gas-cooled nuclear reactor is disposed inside the same pressure vessel as the reactor and has a tube system heated by the gas circulating through the reactor; the pressure vessel is double-walled, and the interspace between these two walls is filled with concrete serving as radiation shielding. The steam generator has a cylindricaIly shaped vertical casing, through which the heating gas circulates, while the tubes are arranged in a plurality of parallel horizontal planes and each of them have the shape of an involute of a circle. The tubes are uniformly distributed over the available surfacemore » in the plane, all the tubes of the same plane being connected in parallel. The exterior extremities of these involute-shaped tubes are each connected with similar tubes disposed in the adjacent lower situated plane, while the interior extremities are connected with tubes in the adjacent higher situated plane. The alimentation of the tubes is performed over annular headers. The tube system is self-supporting, the tubes being joined together by welded spacers. The fluid flow in the tubes is performed by forced circulation. (NPO)« less

NORTH PORTAL-HOT WATER CIRCULATION PUMP CALCULATION-SHOP BUILDING #5006

DOE Office of Scientific and Technical Information (OSTI.GOV)

R. Blackstone

1996-01-25

The purpose of this design analysis and calculation is to size a circulating pump for the service hot water system in the Shop Building 5006, in accordance with the Uniform Plumbing Code (Section 4.4.1) and U.S. Department of Energy Order 6430.1A-1540 (Section 4.4.2). The method used for the calculation is based on Reference 5.2. This consists of determining the total heat transfer from the service hot water system piping to the surrounding environment. The heat transfer is then used to define the total pumping capacity based on a given temperature change in the circulating hot water as it flows throughmore » the closed loop piping system. The total pumping capacity is used to select a pump model from manufacturer's literature. This established the head generation for that capacity and particular pump model. The total length of all hot water supply and return piping including fittings is then estimated from the plumbing drawings which defines the pipe friction losses that must fit within the available pump head. Several iterations may be required before a pump can be selected that satisfies the head-capacity requirements.« less

Flow separation on flapping and rotating profiles with spanwise gradients.

PubMed

Wong, J G; laBastide, B P; Rival, D E

2017-02-15

The growth of leading-edge vortices (LEV) on analogous flapping and rotating profiles has been investigated experimentally. Three time-varying cases were considered: a two-dimensional reference case with a spanwise-uniform angle-of-attack variation α; a case with increasing α towards the profile tip (similar to flapping flyers); and a case with increasing α towards the profile root (similar to rotor blades experiencing an axial gust). It has been shown that the time-varying spanwise angle-of-attack gradient produces a vorticity gradient, which, in combination with spanwise flow, results in a redistribution of circulation along the profile. Specifically, when replicating the angle-of-attack gradient characteristic of a rotor experiencing an axial gust, the spanwise-vorticity gradient is aligned such that circulation increases within the measurement domain. This in turn increases the local LEV growth rate, which is suggestive of force augmentation on the blade. Reversing the relative alignment of the spanwise-vorticity gradient and spanwise flow, thereby replicating that arrangement found in a flapping flyer, was found to reduce local circulation. From this, we can conclude that spanwise flow can be arranged to vary LEV growth to prolong lift augmentation and reduce the unsteadiness of cyclic loads.

Development of a new virtual diagnostic for V3FIT

NASA Astrophysics Data System (ADS)

Trevisan, G. L.; Cianciosa, M. R.; Terranova, D.; Hanson, J. D.

2014-12-01

The determination of plasma equilibria from diagnostic information is a fundamental issue. V3FIT is a fully three-dimensional reconstruction code capable of solving the inverse problem using both magnetic and kinetic measurements. It uses VMEC as core equilibrium solver and supports both free- and fixed-boundary reconstruction approaches. In fixed-boundary mode VMEC does not use explicit information about currents in external coils, even though it has important effects on the shape of the safety factor profile. Indeed, the edge safety factor influences the reversal position in RFP plasmas, which then determines the position of the m = 0 island chain and the edge transport properties. In order to exploit such information a new virtual diagnostic has been developed, that thanks to Ampère's law relates the external current through the center of the torus to the circulation of the toroidal magnetic field on the outermost flux surface. The reconstructions that exploit the new diagnostic are indeed found to better interpret the experimental data with respect to edge physics.

Contributions of sex, testosterone, and androgen receptor CAG repeat number to virtual Morris water maze performance.

PubMed

Nowak, Nicole T; Diamond, Michael P; Land, Susan J; Moffat, Scott D

2014-03-01

The possibility that androgens contribute to the male advantage typically found on measures of spatial cognition has been investigated using a variety of approaches. To date, evidence to support the notion that androgens affect spatial cognition in healthy young adults is somewhat equivocal. The present study sought to clarify the association between testosterone (T) and spatial performance by extending measurements of androgenicity to include both measures of circulating T as well as an androgen receptor-specific genetic marker. The aims of this study were to assess the contributions of sex, T, and androgen receptor CAG repeat number (CAGr) on virtual Morris water task (vMWT) performance in a group of healthy young men and women. The hypothesis that men would outperform women on vMWT outcomes was supported. Results indicate that CAGr may interact with T to impact navigation performance and suggest that consideration of androgen receptor sensitivity is an important consideration in evaluating hormone-behavior relationships. Copyright © 2013 Elsevier Ltd. All rights reserved.

The interplay between estuarine transport and biogeochemical processes in determining the nutrient conditions in bottom layers of non-tidal Gulf of Finland

NASA Astrophysics Data System (ADS)

Kõuts, Mariliis; Raudsepp, Urmas; Maljutenko, Ilja

2017-04-01

In coastal areas, especially estuaries, spatial distribution and seasonal cycling of chemical and biological variables is largely determined by local biogeochemical processes and water transport of different properties. In tidal estuaries, however, biogeochemical processes are affected by tides as frequent water exchange alters nutrient and oxygen concentrations. In wide and deep non-tidal estuary-type marginal seas spatial distribution and seasonal cycling are determined by the mixture of water transport and local biogeochemistry. The Baltic Sea is a stratified water basin where halocline divides the water column into two parts: upper layer, which is horizontally uniform in terms of distribution of chemical and biological parameters, and has clear seasonal cycle; and bottom part, where nutrient and oxygen dynamics is more complex. There water transport and sediment-water interface fluxes play a major role. Our prime focus is the Gulf of Finland in the Baltic Sea. It is a wide, non-tidal and stratified sub-basin known for its high nutrient concentrations and severe oxygen deficiency in summer. We modelled the Baltic Sea (including Gulf of Finland) using ERGOM, a biogeochemical model coupled with circulation model GETM. Seasonal cycling and water circulation were observed with a 40-year simulation from 1966 to 2006. Our results show that in shallow areas above halocline the seasonal cycle of phytoplankton, nutrients and oxygen concentrations is uniform in space. Water circulation does not create inhomogeneous distribution pattern of biogeochemical parameters and their seasonal cycle. The circulation in the Gulf of Finland is strongly modulated by the seasonality of estuarine transport. Below the halocline saline low-oxygen and nutrient-rich water is transported from the open Baltic Proper to the Gulf of Finland in spring and early summer. This results in the highest nutrient concentrations and the poorest oxygen conditions by the end of August. In the shallow area nutrients have high concentrations in March-April before the spring bloom of diatoms starts. Low oxygen and nutrient concentrations are observed at the end of August. There is a qualitative difference of nutrient dynamics between shallow and deep layers but quantification of the role of transport and local biogeochemical processes is still challenging.

System for producing a uniform rubble bed for in situ processes

DOEpatents

Galloway, Terry R.

1983-01-01

A method and a cutter for producing a large cavity filled with a uniform bed of rubblized oil shale or other material, for in situ processing. A raise drill head (72) has a hollow body (76) with a generally circular base and sloping upper surface. A hollow shaft (74) extends from the hollow body (76). Cutter teeth (78) are mounted on the upper surface of the body (76) and relatively small holes (77) are formed in the body (76) between the cutter teeth (78). Relatively large peripheral flutes (80) around the body (76) allow material to drop below the drill head (72). A pilot hole is drilled into the oil shale deposit. The pilot hole is reamed into a large diameter hole by means of a large diameter raise drill head or cutter to produce a cavity filled with rubble. A flushing fluid, such as air, is circulated through the pilot hole during the reaming operation to remove fines through the raise drill, thereby removing sufficient material to create sufficient void space, and allowing the larger particles to fill the cavity and provide a uniform bed of rubblized oil shale.

Particle circulation and solids transport in large bubbling fluidized beds. Progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Homsy, G.M.

1982-04-01

We have undertaken a theoretical study of the possibility of the formation of plumes or channeling when coal particles volatilize upon introduction to a fluidized bed, Fitzgerald (1980). We have completed the analysis of the basic state of uniform flow and are currently completing a stability analysis. We have modified the continuum equations of fluidization, Homsy et al. (1980), to include the source of gas due to volatilization, which we assume to be uniformly distributed spatially. Simplifying these equations and solving leads to the prediction of a basic state analogous to the state of uniform fluidization found when no sourcemore » is present within the medium. We are currently completing a stability analysis of this basic state which will give the critical volatilization rate above which the above simple basic state is unstable. Because of the experimental evidence of Jewett and Lawless (1981), who observed regularly spaced plume-like instabilities upon drying a bed of saturated silica gel, we are considering two-dimensional periodic disturbances. The analysis is similar to that given by Homsy, et al. (1980) and Medlin et al. (1974). We hope to determine the stability limits for this system shortly.« less

Neutrophil Kinetics in Acute Infection*

PubMed Central

Marsh, J. C.; Boggs, D. R.; Cartwright, G. E.; Wintrobe, M. M.

1967-01-01

Neutrophil kinetics of acute experimental infection were studied with diisopropylfluorophosphate-32P labeling in 31 dogs inoculated intrabronchially with pneumococci. In vitro neutrophil labeling indicated a rapid transit time through the blood in early infections, with an elevated marginal granulocyte pool sometimes preceding an elevation of the circulating granulocyte pool. 13 hr after infection, the circulating and total blood granulocyte pools were increased but the rate of neutrophil transit through the blood was normal. During the recovery from infection there was a marked prolongation of neutrophil blood transit time, suggesting virtually complete cessation of bone marrow release of neutrophils into the blood. Labeling of neutrophils in vivo indicated an increased rate of emptying of the bone marrow storage pool proportional to the severity of infection as measured by the fever index. The change in the blood ratio of nonsegmented to segmented neutrophils was a much more accurate index of the severity of infection than the blood granulocyte concentration, correlating significantly with the fever index. PMID:6073999

Recirculation and reutilization of micellar bile lecithin.

PubMed

Robins, S J

1975-09-01

Bile lecithins, solubilized in micellar bile salt and radiolabeled in the 1-acyl fatty acid, phosphorus, and choline positions, were infused in the small bowel of fasted rats. Absorption of each label was virtually complete after 24 h. However, these lecithins were extensively hydrolyzed in the bowel lumen as well as after absorption, and neither the fatty acid nor phosphorus was significantly retained in the enterohepatic circulation or reutilized for biliary lecithin synthesis. In contrast, while choline was also dissociated from absorbed lecithin, choline was instead retained in the liver, reincorporated into newly synthesized hepatic lecithin, and sercreted in biliary lecithin in 10-fold greater amounts than either the fatty acid or phosphorus. However, the extent of choline incorporation into bile lecithin was limited and was not further increased when free choline was directly injected into the portal vein. The data therefore suggest that although only choline of absorbed lecithin is retained in the enterohepatic circulation and preserved for new biliary lecithin synthesis, exogenous choline utilization is regulated by the size of the available hepatic pool.

Application of classical thermodynamic principles to the study of oceanic overturning circulation

NASA Astrophysics Data System (ADS)

Gade, Herman G.; Gustafsson, Karin E.

2004-08-01

Stationary deep-reaching overturning circulation in the ocean is studied by means of classical thermodynamic methods employing closed cycles in pV-space (p, pressure; V, volume). From observed (or computed) density fields, the pV-method may be used to infer the power required for driving a circulation with a given mass flux, or, if the available power is known, the resulting mass flux of the circulation may be assessed. Here, the circulation is assumed to be driven by diapycnal mixing caused by internal disturbances of meteorological and tidal origin and from transfer of geothermal heat through the ocean bottom. The analysis is developed on the basis that potential energy produced by any of these mechanisms is available for driving a circulation of the water masses above its level of generation. The method also takes into account secondary generated potential energy resulting from turbulence developed by the ensuing circulation.Models for different types of circulation are developed and applied to four types of hemispheric circulation with deep-water formation, convection and sinking in an idealized North Atlantic. Our calculations show that the energy input must exceed 15 J kg1 for a cycle to the bottom to exist. An energy supply of 2 TW would in that case support a constant vertical mass flux of 3.2 G kg s1 (3.1 Sv). Computed mass fluxes reaching the surface in the subtropics, corresponding to the same energy input, range between 2.3 5.2 G kg s1, depending on the type of convection/sinking involved. Much higher flux values ensue with ascending water masses reaching the surface at higher geographical latitudes.The study reveals also that compressibility of sea water does not enhance the circulation. An incompressible system, operating within the same mass flux and temperature range, would require about 25% less energy supply, provided that the circulation comprises the same water masses. It is furthermore shown that the meridional distribution of surface salinity, with higher values in the tropics and lower values in regions of deep-water formation, actually enhances the circulation in comparison with one of a more uniform surface salinity. With a homohaline North Atlantic, operating within the same temperature range as presently observed, an increase of 66% of power supply would be required in order that the mass flux of the overturning circulation should remain the same.

3D movies for teaching seafloor bathymetry, plate tectonics, and ocean circulation in large undergraduate classes

NASA Astrophysics Data System (ADS)

Peterson, C. D.; Lisiecki, L. E.; Gebbie, G.; Hamann, B.; Kellogg, L. H.; Kreylos, O.; Kronenberger, M.; Spero, H. J.; Streletz, G. J.; Weber, C.

2015-12-01

Geologic problems and datasets are often 3D or 4D in nature, yet projected onto a 2D surface such as a piece of paper or a projection screen. Reducing the dimensionality of data forces the reader to "fill in" that collapsed dimension in their minds, creating a cognitive challenge for the reader, especially new learners. Scientists and students can visualize and manipulate 3D datasets using the virtual reality software developed for the immersive, real-time interactive 3D environment at the KeckCAVES at UC Davis. The 3DVisualizer software (Billen et al., 2008) can also operate on a desktop machine to produce interactive 3D maps of earthquake epicenter locations and 3D bathymetric maps of the seafloor. With 3D projections of seafloor bathymetry and ocean circulation proxy datasets in a virtual reality environment, we can create visualizations of carbon isotope (δ13C) records for academic research and to aid in demonstrating thermohaline circulation in the classroom. Additionally, 3D visualization of seafloor bathymetry allows students to see features of seafloor most people cannot observe first-hand. To enhance lessons on mid-ocean ridges and ocean basin genesis, we have created movies of seafloor bathymetry for a large-enrollment undergraduate-level class, Introduction to Oceanography. In the past four quarters, students have enjoyed watching 3D movies, and in the fall quarter (2015), we will assess how well 3D movies enhance learning. The class will be split into two groups, one who learns about the Mid-Atlantic Ridge from diagrams and lecture, and the other who learns with a supplemental 3D visualization. Both groups will be asked "what does the seafloor look like?" before and after the Mid-Atlantic Ridge lesson. Then the whole class will watch the 3D movie and respond to an additional question, "did the 3D visualization enhance your understanding of the Mid-Atlantic Ridge?" with the opportunity to further elaborate on the effectiveness of the visualization.

Determining the tensile response of materials at high temperature using DIC and the Virtual Fields Method

NASA Astrophysics Data System (ADS)

Valeri, Guillermo; Koohbor, Behrad; Kidane, Addis; Sutton, Michael A.

2017-04-01

An experimental approach based on Digital Image Correlation (DIC) is successfully applied to predict the uniaxial stress-strain response of 304 stainless steel specimens subjected to nominally uniform temperatures ranging from room temperature to 900 °C. A portable induction heating device equipped with custom made water-cooled copper coils is used to heat the specimen. The induction heater is used in conjunction with a conventional tensile frame to enable high temperature tension experiments. A stereovision camera system equipped with appropriate band pass filters is employed to facilitate the study of full-field deformation response of the material at elevated temperatures. Using the temperature and load histories along with the full-field strain data, a Virtual Fields Method (VFM) based approach is implemented to identify constitutive parameters governing the plastic deformation of the material at high temperature conditions. Results from these experiments confirm that the proposed method can be used to measure the full field deformation of materials subjected to thermo-mechanical loading.

Virtual Round Table on ten leading questions for network research

NASA Astrophysics Data System (ADS)

2004-03-01

The following discussion is an edited summary of the public debate started during the conference “Growing Networks and Graphs in Statistical Physics, Finance, Biology and Social Systems” held in Rome in September 2003. Drafts documents were circulated electronically among experts in the field and additions and follow-up to the original discussion have been included. Among the scientists participating to the discussion L.A.N. Amaral, A. Barrat, A.L. Barabasi, G. Caldarelli, P. De Los Rios, A. Erzan, B. Kahng, R. Mantegna, J.F.F. Mendes, R. Pastor-Satorras, A. Vespignani are acknowledged for their contributions and editing.

Uniform magnetic fields and double-wrapped coil systems: improved techniques for the design of bioelectromagnetic experiments.

PubMed

Kirschvink, J L

1992-01-01

A common mistake in biomagnetic experimentation is the assumption that Helmholtz coils provide uniform magnetic fields; this is true only for a limited volume at their center. Substantial improvements on this design have been made during the past 140 years with systems of three, four, and five coils. Numerical comparisons of the field uniformity generated by these designs are made here, along with a table of construction details and recommendations for their use in experiments in which large volumes of uniform intensity magnetic exposures are needed. Double-wrapping, or systems of bifilar windings, can also help control for the non-magnetic effects of the electric coils used in many experiments. In this design, each coil is wrapped in parallel with two separate, adjacent strands of copper wire, rather than the single strand used normally. If currents are flowing in antiparallel directions, the magnetic fields generated by each strand will cancel and yield virtually no external magnetic field, whereas parallel currents will yield an external field. Both cases will produce similar non-magnetic effects of ohmic heating, and simple measures can reduce the small vibration and electric field differences. Control experiments can then be designed such that the only major difference between treated and untreated groups is the presence or absence of the magnetic field. Double-wrapped coils also facilitate the use of truly double-blind protocol, as the same apparatus can be used either for experimental or control groups.

Experimental study of cassava sun drying

DOE Office of Scientific and Technical Information (OSTI.GOV)

Njie, D.N.; Rumsey, T.R.

1997-03-01

Sun drying experiments were performed to compare drying of cassava chips in sheet-metal trays with drying on mesh wire trays. In the sheet-metal trays, there was air flow across the top of the bed chips, while the mesh wire trays permitted air to flow through the bed. Drying rate was faster and more uniform in the trays with through-flow air circulation. Higher temperatures were reached by chips in the sheet-metal trays than those in the mesh trays because of contact heating, but the drying rate was lower because of the reduced air flow.

Dynamics of a Snowball Earth ocean.

PubMed

Ashkenazy, Yosef; Gildor, Hezi; Losch, Martin; Macdonald, Francis A; Schrag, Daniel P; Tziperman, Eli

2013-03-07

Geological evidence suggests that marine ice extended to the Equator at least twice during the Neoproterozoic era (about 750 to 635 million years ago), inspiring the Snowball Earth hypothesis that the Earth was globally ice-covered. In a possible Snowball Earth climate, ocean circulation and mixing processes would have set the melting and freezing rates that determine ice thickness, would have influenced the survival of photosynthetic life, and may provide important constraints for the interpretation of geochemical and sedimentological observations. Here we show that in a Snowball Earth, the ocean would have been well mixed and characterized by a dynamic circulation, with vigorous equatorial meridional overturning circulation, zonal equatorial jets, a well developed eddy field, strong coastal upwelling and convective mixing. This is in contrast to the sluggish ocean often expected in a Snowball Earth scenario owing to the insulation of the ocean from atmospheric forcing by the thick ice cover. As a result of vigorous convective mixing, the ocean temperature, salinity and density were either uniform in the vertical direction or weakly stratified in a few locations. Our results are based on a model that couples ice flow and ocean circulation, and is driven by a weak geothermal heat flux under a global ice cover about a kilometre thick. Compared with the modern ocean, the Snowball Earth ocean had far larger vertical mixing rates, and comparable horizontal mixing by ocean eddies. The strong circulation and coastal upwelling resulted in melting rates near continents as much as ten times larger than previously estimated. Although we cannot resolve the debate over the existence of global ice cover, we discuss the implications for the nutrient supply of photosynthetic activity and for banded iron formations. Our insights and constraints on ocean dynamics may help resolve the Snowball Earth controversy when combined with future geochemical and geological observations.

A Preliminary Study on the Circulation of an ocean covering a Synchronously Rotating Planet

NASA Astrophysics Data System (ADS)

Matsuo, H.; Ishiwatari, M.; Takehiro, S.; Hayashi, Y.; Nakajima, K.

2012-12-01

Recently, nearly 800 extrasolar planets have been detected. It seems that some of them present into habitable zone, in which planets can have ocean, and such planets rotate synchronously with their central stars. Ocean is necessary for life, and the circulation makes climate mild by heat transport on the earth. The earth is the only planet that has ocean in the solar system so that it has not been understood what oceanic circulation is like in another planets. The purpose of this study is prediction of oceanic circulation on extrasolar planets by using numerical simulation. As a first step, elementary consideration is made. The planet is almost entirely covered with ocean and whose rotation period corresponds with its orbital period. On synchronously rotating planets, the thermal contrast between day-hemisphere and night-hemisphere would be extreme. However, it may be lessend if there is significant zonal heat transport. The circulation in such conditions has not been known well. We performed a numerical experiment based on the linear shallow water equation, assuming that both the evaporation and the precipitation occur only on day-hemisphere (Noda et al., 2011). With these distributions of the evaporation and the precipitation, one may anticipate the circulation occurs in only day-hemisphere. However, the resulting calculation is characterized with zonally uniform zonal flow, which also covers night hemisphere. In addition, the intensity of the flow increases with time. That behavior can be understood by constructing asymptotic solution which is first degree in time. The importance of Coriolis force, which bends meridional flow to zonal flow, is identified. It is implied that, even when only day-hemisphere has the evaporation and precipitation, there may be significant amount of heat can be transported from the day-hemisphere to the night-hemisphere by the strong zonal flow. The growth of zonal flow would be stopped when the evaporation and the precipitation are balanced with mass transport in the bottom Ekman layer.

Application of fluence field modulation to proton computed tomography for proton therapy imaging.

PubMed

Dedes, G; De Angelis, L; Rit, S; Hansen, D; Belka, C; Bashkirov, V; Johnson, R P; Coutrakon, G; Schubert, K E; Schulte, R W; Parodi, K; Landry, G

2017-07-12

This simulation study presents the application of fluence field modulated computed tomography, initially developed for x-ray CT, to proton computed tomography (pCT). By using pencil beam (PB) scanning, fluence modulated pCT (FMpCT) may achieve variable image quality in a pCT image and imaging dose reduction. Three virtual phantoms, a uniform cylinder and two patients, were studied using Monte Carlo simulations of an ideal list-mode pCT scanner. Regions of interest (ROI) were selected for high image quality and only PBs intercepting them preserved full fluence (FF). Image quality was investigated in terms of accuracy (mean) and noise (standard deviation) of the reconstructed proton relative stopping power compared to reference values. Dose calculation accuracy on FMpCT images was evaluated in terms of dose volume histograms (DVH), range difference (RD) for beam-eye-view (BEV) dose profiles and gamma evaluation. Pseudo FMpCT scans were created from broad beam experimental data acquired with a list-mode pCT prototype. FMpCT noise in ROIs was equivalent to FF images and accuracy better than  -1.3%(-0.7%) by using 1% of FF for the cylinder (patients). Integral imaging dose reduction of 37% and 56% was achieved for the two patients for that level of modulation. Corresponding DVHs from proton dose calculation on FMpCT images agreed to those from reference images and 96% of BEV profiles had RD below 2 mm, compared to only 1% for uniform 1% of FF. Gamma pass rates (2%, 2 mm) were 98% for FMpCT while for uniform 1% of FF they were as low as 59%. Applying FMpCT to preliminary experimental data showed that low noise levels and accuracy could be preserved in a ROI, down to 30% modulation. We have shown, using both virtual and experimental pCT scans, that FMpCT is potentially feasible and may allow a means of imaging dose reduction for a pCT scanner operating in PB scanning mode. This may be of particular importance to proton therapy given the low integral dose found outside the target.

Webizing mobile augmented reality content

NASA Astrophysics Data System (ADS)

Ahn, Sangchul; Ko, Heedong; Yoo, Byounghyun

2014-01-01

This paper presents a content structure for building mobile augmented reality (AR) applications in HTML5 to achieve a clean separation of the mobile AR content and the application logic for scaling as on the Web. We propose that the content structure contains the physical world as well as virtual assets for mobile AR applications as document object model (DOM) elements and that their behaviour and user interactions are controlled through DOM events by representing objects and places with a uniform resource identifier. Our content structure enables mobile AR applications to be seamlessly developed as normal HTML documents under the current Web eco-system.

The vacuum platform

NASA Astrophysics Data System (ADS)

McNab, A.

2017-10-01

This paper describes GridPP’s Vacuum Platform for managing virtual machines (VMs), which has been used to run production workloads for WLCG and other HEP experiments. The platform provides a uniform interface between VMs and the sites they run at, whether the site is organised as an Infrastructure-as-a-Service cloud system such as OpenStack, or an Infrastructure-as-a-Client system such as Vac. The paper describes our experience in using this platform, in developing and operating VM lifecycle managers Vac and Vcycle, and in interacting with VMs provided by LHCb, ATLAS, ALICE, CMS, and the GridPP DIRAC service to run production workloads.

Astronomical virtual observatory and the place and role of Bulgarian one

NASA Astrophysics Data System (ADS)

Petrov, Georgi; Dechev, Momchil; Slavcheva-Mihova, Luba; Duchlev, Peter; Mihov, Bojko; Kochev, Valentin; Bachev, Rumen

2009-07-01

Virtual observatory could be defined as a collection of integrated astronomical data archives and software tools that utilize computer networks to create an environment in which research can be conducted. Several countries have initiated national virtual observatory programs that combine existing databases from ground-based and orbiting observatories, scientific facility especially equipped to detect and record naturally occurring scientific phenomena. As a result, data from all the world's major observatories will be available to all users and to the public. This is significant not only because of the immense volume of astronomical data but also because the data on stars and galaxies has been compiled from observations in a variety of wavelengths-optical, radio, infrared, gamma ray, X-ray and more. In a virtual observatory environment, all of this data is integrated so that it can be synthesized and used in a given study. During the autumn of the 2001 (26.09.2001) six organizations from Europe put the establishment of the Astronomical Virtual Observatory (AVO)-ESO, ESA, Astrogrid, CDS, CNRS, Jodrell Bank (Dolensky et al., 2003). Its aims have been outlined as follows: - To provide comparative analysis of large sets of multiwavelength data; - To reuse data collected by a single source; - To provide uniform access to data; - To make data available to less-advantaged communities; - To be an educational tool. The Virtual observatory includes: - Tools that make it easy to locate and retrieve data from catalogues, archives, and databases worldwide; - Tools for data analysis, simulation, and visualization; - Tools to compare observations with results obtained from models, simulations and theory; - Interoperability: services that can be used regardless of the clients computing platform, operating system and software capabilities; - Access to data in near real-time, archived data and historical data; - Additional information - documentation, user-guides, reports, publications, news and so on. This large growth of astronomical data and the necessity of an easy access to those data led to the foundation of the International Virtual Observatory Alliance (IVOA). IVOA was formed in June 2002. By January 2005, the IVOA has grown to include 15 funded VO projects from Australia, Canada, China, Europe, France, Germany, Hungary, India, Italy, Japan, Korea, Russia, Spain, the United Kingdom, and the United States. At the time being Bulgaria is not a member of European Astronomical Virtual Observatory and as the Bulgarian Virtual Observatory is not a legal entity, we are not members of IVOA. The main purpose of the project is Bulgarian Virtual Observatory to join the leading virtual astronomical institutions in the world. Initially the Bulgarian Virtual Observatory will include: - BG Galaxian virtual observatory; - BG Solar virtual observatory; - Department Star clusters of IA, BAS; - WFPDB group of IA, BAS. All available data will be integrated in the Bulgarian centers of astronomical data, conducted by the Wide Field Plate Archive data centre. For the above purpose POSTGRESQL or/and MySQL will be installed on the server of BG-VO and SAADA tools, ESO-MEX or/and DAL ToolKit to transform our FITS files in standard format for VO-tools. A part of the participants was acquainted with the principles of these products during the "Days of virtual observatory in Sofia" January, 2008.

Geothermal influences on the abyssal ocean

NASA Astrophysics Data System (ADS)

Emile-Geay, J.; Madec, G.

2017-12-01

Long considered a negligible contribution to ocean dynamics, geothermal heat flow (GHF) is now increasingly recognized as an important contributor to the large scale ocean's deep structure and circulation. This presentation will review the history of theories regarding geothermal influences on the abyssal ocean. Though the contribution to the thermal structure was recognized early on, its potential in driving a circulation [Worthington, 1968] was largely ignored on the grounds that it could not materially affect potential vorticity. Huang [JPO, 1999] proposed that GHF may provide 30-50% of the energy available for deep mixing, a calculation that later proved too optimistic [Wunsch & Ferrari ARFM 2004]. Model simulations suggested that a uniform GHF of 50 mW/m2 could drive an abyssal of a few Sverdrups (1 Sv = 106 m3.s-1) [Adcroft et al, GRL 2001], but it was not until Emile-Geay & Madec [OS, 2009] (EM09) that GHF began to be taken seriously [Mashayek et al, GRL 2013; Voldoire et al. Clim. Dyn. 2013; Dufresnes et al., Clim. Dyn. 2013]. Using analytical and numerical approaches, the study made 3 main points: GHF brings as much energy to the deep ocean as intense diapycnal mixing (1 cm2/s). GHF consumes the densest water masses, inducing a deep circulation of 5 Sv even without mixing. This circulation varies in inverse proportion to abyssal stratification. The spatial structure of GHF, highest at mid-ocean ridges and lowest in abyssal plains, matters far less than the fact that it bathes vast fractions of the ocean floor in a relatively low, constant flux. EM09 concluded that GHF "is an important actor of abyssal dynamics, and should no longer be neglected in oceanographic studies". Recent work has confirmed that geothermal heat flow is of comparable importance to ocean circulation as bottom-intensified mixing induced by internal wave breaking [De Lavergne et al, JPO 2016a,b]. Thus, including GHF in ocean general circulation models improves abyssal structure and circulation. We conclude with a perspective on the role of conductive geothermal heat loss versus localized, advective hydrothermal heat flow on abyssal dynamics, and delineate unsolved research problems for the years ahead.

Integrated geophysical and hydrothermal models of flank degassing and fluid flow at Masaya Volcano, Nicaragua

USGS Publications Warehouse

Sanford, Ward E.; Pearson, S.C.P.; Kiyosugi, K.; Lehto, H.L.; Saballos, J.A.; Connor, C.B.

2012-01-01

We investigate geologic controls on circulation in the shallow hydrothermal system of Masaya volcano, Nicaragua, and their relationship to surface diffuse degassing. On a local scale (~250 m), relatively impermeable normal faults dipping at ~60° control the flowpath of water vapor and other gases in the vadose zone. These shallow normal faults are identified by modeling of a NE-SW trending magnetic anomaly of up to 2300 nT that corresponds to a topographic offset. Elevated SP and CO2 to the NW of the faults and an absence of CO2 to the SE suggest that these faults are barriers to flow. TOUGH2 numerical models of fluid circulation show enhanced flow through the footwalls of the faults, and corresponding increased mass flow and temperature at the surface (diffuse degassing zones). On a larger scale, TOUGH2 modeling suggests that groundwater convection may be occurring in a 3-4 km radial fracture zone transecting the entire flank of the volcano. Hot water rising uniformly into the base of the model at 1 x 10-5 kg/m2s results in convection that focuses heat and fluid and can explain the three distinct diffuse degassing zones distributed along the fracture. Our data and models suggest that the unusually active surface degassing zones at Masaya volcano can result purely from uniform heat and fluid flux at depth that is complicated by groundwater convection and permeability variations in the upper few km. Therefore isolating the effects of subsurface geology is vital when trying to interpret diffuse degassing in light of volcanic activity.

Regional Climate Simulation and Data Assimilation with Variable-Resolution GCMs

NASA Technical Reports Server (NTRS)

Fox-Rabinovitz, Michael S.

2002-01-01

Variable resolution GCMs using a global stretched grid (SG) with enhanced regional resolution over one or multiple areas of interest represents a viable new approach to regional climateklimate change and data assimilation studies and applications. The multiple areas of interest, at least one within each global quadrant, include the major global mountains and major global monsoonal circulations over North America, South America, India-China, and Australia. They also can include the polar domains, and the European and African regions. The SG-approach provides an efficient regional downscaling to mesoscales, and it is an ideal tool for representing consistent interactions of globaYlarge- and regionallmeso- scales while preserving the high quality of global circulation. Basically, the SG-GCM simulations are no different from those of the traditional uniform-grid GCM simulations besides using a variable-resolution grid. Several existing SG-GCMs developed by major centers and groups are briefly described. The major discussion is based on the GEOS (Goddard Earth Observing System) SG-GCM regional climate simulations.

Nanomedicines for cancer therapy: state-of-the-art and limitations to pre-clinical studies that hinder future developments

NASA Astrophysics Data System (ADS)

Dawidczyk, Charlene; Russell, Luisa; Searson, Peter

2014-08-01

The ability to efficiently deliver a drug or gene to a tumor site is dependent on a wide range of factors including circulation time, interactions with the mononuclear phagocyte system, extravasation from circulation at the tumor site, targeting strategy, release from the delivery vehicle, and uptake in cancer cells. Nanotechnology provides the possibility of creating delivery systems where the design constraints are decoupled, allowing new approaches for reducing the unwanted side effects of systemic delivery, increasing tumor accumulation, and improving efficacy. The physico-chemical properties of nanoparticle-based delivery platforms introduce additional complexity associated with pharmacokinetics and tumor accumulation. To assess the impact of nanoparticle-based delivery systems, we first review the design strategies and pharmacokinetics of FDA-approved nanomedicines. Next we review nanomedicines under development, summarizing the range of nanoparticle platforms, strategies for targeting, and pharmacokinetics. We show how the lack of uniformity in preclinical trials prevents systematic comparison and hence limits advances in the field.

Vortex generation and mixing in three-dimensional supersonic combustors

NASA Technical Reports Server (NTRS)

Riggins, D. W.; Vitt, P. H.

1993-01-01

The generation and evolution of the flow vorticity established by instream injector ramps in a high Mach number/high enthalpy scramjet combustor flow-field are described in detail for a number of computational cases. Classical fluid dynamic circulation is presented for these cases in order to clarify the spatial distribution and convection of the vorticity. The ability of the simulations to accurately represent Stokes Law of circulation is discussed and shown. In addition, the conservation of swirl (effectively the moment-of-momentum theorem) is presented for these flows. The impact of both turbulent diffusion and the vortex/ramp non-uniformity on the downstream mixing rate is clearly illustrated. A correlation over the length of the combustor between fuel-air mixing and a parameter called the vortex stirring length is demonstrated. Finally, computational results for a representative ramp injector are compared with experimental data. Influence of the stream vorticity on the effective turbulent Prandtl number used in the simulation is discussed.

Thermoelectric refrigerator

NASA Technical Reports Server (NTRS)

Park, Brian V. (Inventor); Smith, Jr., Malcolm C. (Inventor); McGrath, Ralph D. (Inventor); Gilley, Michael D. (Inventor); Criscuolo, Lance (Inventor); Nelson, John L. (Inventor)

1996-01-01

A refrigerator is provided which combines the benefits of superinsulation materials with thermoelectric devices and phase change materials to provide an environmentally benign system that is energy efficient and can maintain relatively uniform temperatures for extended periods of time with relatively low electrical power requirements. The refrigerator includes a thermoelectric assembly having a thermoelectric device with a hot sink and a cold sink. The superinsulation materials include a plurality of vacuum panels. The refrigerator is formed from an enclosed structure having a door. The vacuum panels may be contained within the walls of the enclosed structure and the door. By mounting the thermoelectric assembly on the door, the manufacturer of the enclosed structure is simplified and the overall R rating of the refrigerator increased. Also an electrical motor and propellers may be mounted on the door to assist in the circulation of air to improve the efficiency of the cold sink and the hot sink. A propeller and/or impeller is preferably mounted within the refrigerator to assist in establishing the desired air circulation flow path.

Characteristics of stratosphere-troposphere exchange in a general circulation model

NASA Technical Reports Server (NTRS)

Mote, Philip W.; Holton, James R.; Boville, Byron A.

1994-01-01

In this study we examine mass exchange, water vapor exchange, and the behavior of idealized tracers and parcels to diagnose Stratosphere-Troposphere Exchange (STE) in the National Center for Atmospheric Research (NCAR) General Circulation Model (GCM), the Community Climate Model (CCM2). The CCM2 correctly represents the seasonality of mass exchange across 100 hPa, but values are uniformly too strong. Water vapor, however, indicates that tropical STE is not well represented in the CCM2; even though mean tropopause temperatures are colder than observed, the lower stratosphere is too moist. Most net mass flux occurs at water vapor mixing ratios of about 4-5 parts per million by volume (ppmv), about 1 ppmv too moist. Vertical resolution has little impact on the nature of tropical STE. In midlatitudes, CCM2 more successfully represents STE, which occurs in developing baroclinic waves and stationary anticyclones. Exchange from troposphere to stratosphere does occur but only influences the lowest few kilometers of the extratropical stratosphere, even for tracers with large vertical gradients.

Cardiopulmonary Circuit Models for Predicting Injury to the Heart

NASA Astrophysics Data System (ADS)

Ward, Richard; Wing, Sarah; Bassingthwaighte, James; Neal, Maxwell

2004-11-01

Circuit models have been used extensively in physiology to describe cardiopulmonary function. Such models are being used in the DARPA Virtual Soldier (VS) Project* to predict the response to injury or physiological stress. The most complex model consists of systemic circulation, pulmonary circulation, and a four-chamber heart sub-model. This model also includes baroreceptor feedback, airway mechanics, gas exchange, and pleural pressure influence on the circulation. As part of the VS Project, Oak Ridge National Laboratory has been evaluating various cardiopulmonary circuit models for predicting the effects of injury to the heart. We describe, from a physicist's perspective, the concept of building circuit models, discuss both unstressed and stressed models, and show how the stressed models are used to predict effects of specific wounds. *This work was supported by a grant from the DARPA, executed by the U.S. Army Medical Research and Materiel Command/TATRC Cooperative Agreement, Contract # W81XWH-04-2-0012. The submitted manuscript has been authored by the U.S. Department of Energy, Office of Science of the Oak Ridge National Laboratory, managed for the U.S. DOE by UT-Battelle, LLC, under contract No. DE-AC05-00OR22725. Accordingly, the U.S. Government retains a non-exclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purpose.

Pathways of basal meltwater from Antarctic ice shelves: A model study

NASA Astrophysics Data System (ADS)

Kusahara, Kazuya; Hasumi, Hiroyasu

2014-09-01

We investigate spreading pathways of basal meltwater released from all Antarctic ice shelves using a circumpolar coupled ice shelf-sea ice-ocean model that reproduces major features of the Southern Ocean circulation, including the Antarctic Circumpolar Current (ACC). Several independent virtual tracers are used to identify detailed pathways of basal meltwaters. The spreading pathways of the meltwater tracers depend on formation sites, because the meltwaters are transported by local ambient ocean circulation. Meltwaters from ice shelves in the Weddell and Amundsen-Bellingshausen Seas in surface/subsurface layers are effectively advected to lower latitudes with the ACC. Although a large portion of the basal meltwaters is present in surface and subsurface layers, a part of the basal meltwaters penetrates into the bottom layer through active dense water formation along the Antarctic coastal margins. The signals at the seafloor extend along the topography, showing a horizontal distribution similar to the observed spreading of Antarctic Bottom Water. Meltwaters originating from ice shelves in the Weddell and Ross Seas and in the Indian sector significantly contribute to the bottom signals. A series of numerical experiments in which thermodynamic interaction between the ice shelf and ocean is neglected regionally demonstrates that the basal meltwater of each ice shelf impacts sea ice and/or ocean thermohaline circulation in the Southern Ocean. This article was corrected on 10 OCT 2014. See the end of the full text for details.

The Effect of Uniform Background Flow on Vortex Ring Formation and Pinch-off

NASA Astrophysics Data System (ADS)

Krueger, Paul S.; Dabiri, John O.; Gharib, Morteza

2002-11-01

Experimental investigations of vortex ring formation are extended to include the effects of a uniform background flow, in a manner relevant to the locomotion of aquatic animals utilizing jet propulsion. Gharib et. al. [J. Fluid Mech. 360, 121 (1998)] generated vortex rings using a piston/cylinder apparatus with relatively large discharge times to demonstrate that the vortex ring at the leading edge of the jet attains its maximum circulation at a piston stroke-to-diameter ratio L/D of 4. This "formation number" is robust over a range of piston motions and cylinder boundary conditions, and can be explained in terms of the Kelvin-Benjamin variational principle. To determine the effect of background flow on formation number and pinch-off of the leading vortex ring, uniform co-flow is established in a large annulus surrounding the vortex generator. The ratio of co-flow velocity to piston velocity is varied between 0 and 1. In addition, the co-flow is initiated at times both before and after the start of vortex ring formation. We present results for stroke ratios L/D = 2 and L/D = 8, in order to discern effects of the co-flow on the leading vortex ring in isolation and in the presence of a trailing jet.

Transport of cardiovascular microbubbles in gas embolotherapy

NASA Astrophysics Data System (ADS)

Bull, Joseph L.; Calderon, Andres J.; Eshpuniyani, Brijesh; Valassis, Doug; Fowlkes, J. Brian

2006-11-01

This work is motivated by our ongoing development of a novel gas embolotherapy technique to occlude blood flow to tumors using gas bubbles that are selectively formed by the in vivo acoustic vaporization of liquid perfluorocarbon droplets. The droplets are small enough to pass through the microcirculation, but the subsequent bubbles are large enough to lodge in vessels. The uniformity of tumor infarction depends on the transport the blood-borne bubbles before they stick. We theoretically and experimentally investigate the transport of gas bubbles through bifurcating blood vessels. More homogenous bubble splitting is observed for higher values of capillary numbers and lower values of Bond numbers. The dependence of bubble lodging on flow parameters is also investigated, and several modes of bubble lodging and sticking are identified. These findings indicate the ability of gas bubbles to occlude flow and suggest the potential for development of treatment strategies that uniformly occlude the tumor circulation while minimizing collateral infarction. This work is supported by NSF grant BES-0301278 and NIH grant EB003541.

Inverse design of centrifugal compressor vaned diffusers in inlet shear flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zangeneh, M.

1996-04-01

A three-dimensional inverse design method in which the blade (or vane) geometry is designed for specified distributions of circulation and blade thickness is applied to the design of centrifugal compressor vaned diffusers. Two generic diffusers are designed, one with uniform inlet flow (equivalent to a conventional design) and the other with a sheared inlet flow. The inlet shear flow effects are modeled in the design method by using the so-called ``Secondary Flow Approximation`` in which the Bernoulli surfaces are convected by the tangentially mean inviscid flow field. The difference between the vane geometry of the uniform inlet flow and nonuniformmore » inlet flow diffusers is found to be most significant from 50 percent chord to the trailing edge region. The flows through both diffusers are computed by using Denton`s three-dimensional inviscid Euler solver and Dawes` three-dimensional Navier-Stokes solver under sheared in-flow conditions. The predictions indicate improved pressure recovery and internal flow field for the diffuser designed for shear inlet flow conditions.« less

Aerosol chemistry during the wet season in central Amazonia - The influence of long-range transport

NASA Technical Reports Server (NTRS)

Talbot, R. W.; Andreae, M. O.; Berresheim, H.; Artaxo, P.; Garstang, M.

1990-01-01

The temporal variation in the concentration and chemistry of the atmospheric aerosol over central Amazonia, Brazil, during the 1987 wet season is discussed based on ground and aircraft collected data obtained during the NASA GTE ABLE 2B expedition conducted in April/May 1987. It is found that wet-season aerosol concentrations and composition are variable in contrast to the more uniform biogenic aerosol observed during the 1985 dry season; four distinct intervals of enhanced aerosol concentration coincided with short periods (3 to 5 d) of extensive rainfall. It is hypothesized that aerosol chemistry in Amazonia during the wet season is strongly influenced by long-range transport of soil dust, marine aerosol, and possibly biomass combustion products advected into the central Basin by large-scale tropospheric circulation, producing periodic pulses of material input to local boundary layer air. The resultant wet-season aerosol regime is dynamic, in contrast to the uniformity of natural biogenic aerosols during the dry season.

Grid effects on the derived ion temperature and ram velocity from the simulated results of the retarding potential analyzer data

NASA Astrophysics Data System (ADS)

Chao, C. K.; Su, S.-Y.; Yeh, H. C.

2003-12-01

The ROCSAT-1 satellite circulating at 600 km altitude in the low- and mid-latitude topside ionosphere carries a retarding potential analyzer to measure the ion composition, temperature, and the plasma flow velocity in the ram direction. Based on an existing three-dimensional model, the particle's motion inside the instrument is simulated with the exact wire and mesh sizes but with a smaller aperture of the real sensor configuration. The simulation results indicate that the retarding grids could not provide a uniform retarding potential barrier to completely repel low energy particles. Some of low energy particles could pass through those grids and arrive at the collector. The leakage will cause the ram velocity to be over-estimated for by about 180 m/sec. Furthermore, the simulated O + temperature derived from the I-V curve is lower than the input temperature due to ion losses from colliding with the grids from the non-uniform potential field generated by the high retarding voltage.

Dynamic phenomena and human activity in an artificial society

NASA Astrophysics Data System (ADS)

Grabowski, A.; Kruszewska, N.; Kosiński, R. A.

2008-12-01

We study dynamic phenomena in a large social network of nearly 3×104 individuals who interact in the large virtual world of a massive multiplayer online role playing game. On the basis of a database received from the online game server, we examine the structure of the friendship network and human dynamics. To investigate the relation between networks of acquaintances in virtual and real worlds, we carried out a survey among the players. We show that, even though the virtual network did not develop as a growing graph of an underlying network of social acquaintances in the real world, it influences it. Furthermore we find very interesting scaling laws concerning human dynamics. Our research shows how long people are interested in a single task and how much time they devote to it. Surprisingly, exponent values in both cases are close to -1 . We calculate the activity of individuals, i.e., the relative time daily devoted to interactions with others in the artificial society. Our research shows that the distribution of activity is not uniform and is highly correlated with the degree of the node, and that such human activity has a significant influence on dynamic phenomena, e.g., epidemic spreading and rumor propagation, in complex networks. We find that spreading is accelerated (an epidemic) or decelerated (a rumor) as a result of superspreaders’ various behavior.

The Virtual Space Physics Observatory: Quick Access to Data and Tools

NASA Technical Reports Server (NTRS)

Cornwell, Carl; Roberts, D. Aaron; McGuire, Robert E.

2006-01-01

The Virtual Space Physics Observatory (VSPO; see http://vspo.gsfc.nasa.gov) has grown to provide a way to find and access about 375 data products and services from over 100 spacecraft/observatories in space and solar physics. The datasets are mainly chosen to be the most requested, and include most of the publicly available data products from operating NASA Heliophysics spacecraft as well as from solar observatories measuring across the frequency spectrum. Service links include a "quick orbits" page that uses SSCWeb Web Services to provide a rapid answer to questions such as "What spacecraft were in orbit in July 1992?" and "Where were Geotail, Cluster, and Polar on 2 June 2001?" These queries are linked back to the data search page. The VSPO interface provides many ways of looking for data based on terms used in a registry of resources using the SPASE Data Model that will be the standard for Heliophysics Virtual Observatories. VSPO itself is accessible via an API that allows other applications to use it as a Web Service; this has been implemented in one instance using the ViSBARD visualization program. The VSPO will become part of the Space Physics Data Facility, and will continue to expand its access to data. A challenge for all VOs will be to provide uniform access to data at the variable level, and we will be addressing this question in a number of ways.

Lagrangian ocean analysis: Fundamentals and practices

DOE PAGES

van Sebille, Erik; Griffies, Stephen M.; Abernathey, Ryan; ...

2017-11-24

Lagrangian analysis is a powerful way to analyse the output of ocean circulation models and other ocean velocity data such as from altimetry. In the Lagrangian approach, large sets of virtual particles are integrated within the three-dimensional, time-evolving velocity fields. A variety of tools and methods for this purpose have emerged, over several decades. Here, we review the state of the art in the field of Lagrangian analysis of ocean velocity data, starting from a fundamental kinematic framework and with a focus on large-scale open ocean applications. Beyond the use of explicit velocity fields, we consider the influence of unresolvedmore » physics and dynamics on particle trajectories. We comprehensively list and discuss the tools currently available for tracking virtual particles. We then showcase some of the innovative applications of trajectory data, and conclude with some open questions and an outlook. Our overall goal of this review paper is to reconcile some of the different techniques and methods in Lagrangian ocean analysis, while recognising the rich diversity of codes that have and continue to emerge, and the challenges of the coming age of petascale computing.« less

Lagrangian ocean analysis: Fundamentals and practices

NASA Astrophysics Data System (ADS)

van Sebille, Erik; Griffies, Stephen M.; Abernathey, Ryan; Adams, Thomas P.; Berloff, Pavel; Biastoch, Arne; Blanke, Bruno; Chassignet, Eric P.; Cheng, Yu; Cotter, Colin J.; Deleersnijder, Eric; Döös, Kristofer; Drake, Henri F.; Drijfhout, Sybren; Gary, Stefan F.; Heemink, Arnold W.; Kjellsson, Joakim; Koszalka, Inga Monika; Lange, Michael; Lique, Camille; MacGilchrist, Graeme A.; Marsh, Robert; Mayorga Adame, C. Gabriela; McAdam, Ronan; Nencioli, Francesco; Paris, Claire B.; Piggott, Matthew D.; Polton, Jeff A.; Rühs, Siren; Shah, Syed H. A. M.; Thomas, Matthew D.; Wang, Jinbo; Wolfram, Phillip J.; Zanna, Laure; Zika, Jan D.

2018-01-01

Lagrangian analysis is a powerful way to analyse the output of ocean circulation models and other ocean velocity data such as from altimetry. In the Lagrangian approach, large sets of virtual particles are integrated within the three-dimensional, time-evolving velocity fields. Over several decades, a variety of tools and methods for this purpose have emerged. Here, we review the state of the art in the field of Lagrangian analysis of ocean velocity data, starting from a fundamental kinematic framework and with a focus on large-scale open ocean applications. Beyond the use of explicit velocity fields, we consider the influence of unresolved physics and dynamics on particle trajectories. We comprehensively list and discuss the tools currently available for tracking virtual particles. We then showcase some of the innovative applications of trajectory data, and conclude with some open questions and an outlook. The overall goal of this review paper is to reconcile some of the different techniques and methods in Lagrangian ocean analysis, while recognising the rich diversity of codes that have and continue to emerge, and the challenges of the coming age of petascale computing.

Lagrangian ocean analysis: Fundamentals and practices

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Sebille, Erik; Griffies, Stephen M.; Abernathey, Ryan

Lagrangian analysis is a powerful way to analyse the output of ocean circulation models and other ocean velocity data such as from altimetry. In the Lagrangian approach, large sets of virtual particles are integrated within the three-dimensional, time-evolving velocity fields. A variety of tools and methods for this purpose have emerged, over several decades. Here, we review the state of the art in the field of Lagrangian analysis of ocean velocity data, starting from a fundamental kinematic framework and with a focus on large-scale open ocean applications. Beyond the use of explicit velocity fields, we consider the influence of unresolvedmore » physics and dynamics on particle trajectories. We comprehensively list and discuss the tools currently available for tracking virtual particles. We then showcase some of the innovative applications of trajectory data, and conclude with some open questions and an outlook. Our overall goal of this review paper is to reconcile some of the different techniques and methods in Lagrangian ocean analysis, while recognising the rich diversity of codes that have and continue to emerge, and the challenges of the coming age of petascale computing.« less

Third generation anthropomorphic physical phantom for mammography and DBT: incorporating voxelized 3D printing and uniform chest wall QC region

NASA Astrophysics Data System (ADS)

Zhao, Christine; Solomon, Justin; Sturgeon, Gregory M.; Gehm, Michael E.; Catenacci, Matthew; Wiley, Benjamin J.; Samei, Ehsan; Lo, Joseph Y.

2017-03-01

Physical breast phantoms provide a standard method to test, optimize, and develop clinical mammography systems, including new digital breast tomosynthesis (DBT) systems. In previous work, we produced an anthropomorphic phantom based on 500x500x500 μm breast CT data using commercial 3D printing. We now introduce an improved phantom based on a new cohort of virtual models with 155x155x155 μm voxels and fabricated through voxelized 3D printing and dithering, which confer higher resolution and greater control over contrast. This new generation includes a uniform chest wall extension for evaluating conventional QC metrics. The uniform region contains a grayscale step wedge, chest wall coverage markers, fiducial markers, spheres, and metal ink stickers of line pairs and edges to assess contrast, resolution, artifact spread function, MTF, and other criteria. We also experimented with doping photopolymer material with calcium, iodine, and zinc to increase our current contrast. In particular, zinc was discovered to significantly increase attenuation beyond 100% breast density with a linear relationship between zinc concentration and attenuation or breast density. This linear relationship was retained when the zinc-doped material was applied in conjunction with 3D printing. As we move towards our long term goal of phantoms that are indistinguishable from patients, this new generation of anthropomorphic physical breast phantom validates our voxelized printing process, demonstrates the utility of a uniform QC region with features from 3D printing and metal ink stickers, and shows potential for improved contrast via doping.

Modeled alongshore circulation and morphologic evolution onshore of a large submarine canyon

NASA Astrophysics Data System (ADS)

Hansen, J. E.; Raubenheimer, B.; List, J. H.; Elgar, S.; Guza, R. T.; Lippmann, T. C.

2012-12-01

Alongshore circulation and morphologic evolution observed at an ocean beach during the Nearshore Canyon Experiment, onshore of a large submarine canyon in San Diego, CA (USA), are investigated using a two-dimensional depth-averaged numerical model (Delft3D). The model is forced with waves observed in ~500 m water depth and tidal constituents derived from satellite altimetry. Consistent with field observations, the model indicates that refraction of waves over the canyon results in wave focusing ~500 m upcoast of the canyon and shadowing onshore of the canyon. The spatial variability in the modeled wave field results in a corresponding non-uniform alongshore circulation field. In particular, when waves approach from the northwest the alongshore flow converges near the wave focal zone, while waves that approach from the southwest result in alongshore flow that diverges away from the wave focal zone. The direction and magnitude of alongshore flows are determined by a balance between the (often opposing) radiation stress and alongshore pressure gradients, consistent with observations and previous results. The largest observed morphologic evolution, vertical accretion of about 1.5 m in about 3 m water depth near the wave focal zone, occurred over a one-week period when waves from the northwest reached heights of 1.8 m. The model, with limited tuning, replicates the magnitude and spatial extent of the observed accretion and indicates that net accretion of the cross-shore profile was owing to alongshore transport from converging alongshore flows. The good agreement between the observed and modeled morphology change allows for an in-depth examination of the alongshore force balance that resulted in the sediment convergence. These results indicate that, at least in this case, a depth-averaged hydrodynamic model can replicate observed surfzone morphologic change resulting from forcing that is strongly non-uniform in the alongshore. Funding was provided by the Office of Naval Research, The National Science Foundation, a Woods Hole Oceanographic Institution and United States Geological Survey joint postdoctoral fellowship, and a National Security Science and Engineering Faculty Fellowship.

"Wham bam tap scratch screech": the brief-but proud-history of Lesbian London, 1991-1994.

PubMed

Lavelle, Ashley

2014-01-01

During its time in circulation from 1991-1994, Lesbian London set out to provide a voice for lesbians, but also to resist what it saw as the creeping malaise of commercialization and depoliticization of lesbian, gay, bisexual, and transgender (LGBT) communities. Virtually every topic of relevance to its readership was covered within the pages of each monthly issue, available free of charge. Despite its standout contribution, the magazine has been all but forgotten. Moreover, its untimely demise raises important questions about the future prospects of radical, non-commercial publications as well as about the direction of LGBT politics.

Distensibility and pressure-flow relationship of the pulmonary circulation. II. Multibranched model.

PubMed

Bshouty, Z; Younes, M

1990-04-01

The contribution of distensibility and recruitment to the distinctive behavior of the pulmonary circulation is not known. To examine this question we developed a multibranched model in which an arterial vascular bed bifurcates sequentially up to 8 parallel channels that converge and reunite at the venous side to end in the left atrium. Eight resistors representing the capillary bed separate the arterial and venous beds. The elastic behavior of capillaries and extra-alveolar vessels was modeled after Fung and Sobin (Circ. Res. 30: 451-490, 1972) and Smith and Mitzner (J. Appl. Physiol. 48: 450-467, 1980), respectively. Forces acting on each component are modified and calculated individually, thus enabling the user to explore the effects of parallel and longitudinal heterogeneities in applied forces (e.g., gravity, vasomotor tone). Model predictions indicate that the contribution of distensibility to nonlinearities in the pressure-flow (P-F) and atrial-pulmonary arterial pressure (Pla-Ppa) relationships is substantial, whereas gravity-related recruitment contributes very little to these relationships. In addition, Pla-Ppa relationships, obtained at a constant flow, have no discriminating ability in identifying the presence or absence of a waterfall along the circulation. The P-F relationship is routinely shifted in a parallel fashion, within the physiological flow range, whenever extra forces (e.g., lung volume, tone) are applied uniformly at one or more branching levels, regardless of whether a waterfall is created. For a given applied force, the magnitude of parallel shift varies with proportion of the circulation subjected to the added force and with Pla.

Epigenetic Biomarkers and Cardiovascular Disease: Circulating MicroRNAs.

PubMed

de Gonzalo-Calvo, David; Iglesias-Gutiérrez, Eduardo; Llorente-Cortés, Vicenta

2017-09-01

MicroRNAs (miRNAs) are a class of small noncoding RNA (20-25 nucleotides) involved in gene regulation. In recent years, miRNAs have emerged as a key epigenetic mechanism in the development and physiology of the cardiovascular system. These molecular species regulate basic functions in virtually all cell types, and are therefore directly associated with the pathophysiology of a large number of cardiovascular diseases. Since their relatively recent discovery in extracellular fluids, miRNAs have been studied as potential biomarkers of disease. A wide array of studies have proposed miRNAs as circulating biomarkers of different cardiovascular pathologies (eg, myocardial infarction, coronary heart disease, and heart failure, among others), which may have superior physicochemical and biochemical properties than the conventional protein indicators currently used in clinical practice. In the present review, we provide a brief introduction to the field of miRNAs, paying special attention to their potential clinical application. This includes their possible role as new diagnostic or prognostic biomarkers in cardiovascular disease. Copyright © 2017 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Renal glucose metabolism in normal physiological conditions and in diabetes.

PubMed

Alsahli, Mazen; Gerich, John E

2017-11-01

The kidney plays an important role in glucose homeostasis via gluconeogenesis, glucose utilization, and glucose reabsorption from the renal glomerular filtrate. After an overnight fast, 20-25% of glucose released into the circulation originates from the kidneys through gluconeogenesis. In this post-absorptive state, the kidneys utilize about 10% of all glucose utilized by the body. After glucose ingestion, renal gluconeogenesis increases and accounts for approximately 60% of endogenous glucose release in the postprandial period. Each day, the kidneys filter approximately 180g of glucose and virtually all of this is reabsorbed into the circulation. Hormones (most importantly insulin and catecholamines), substrates, enzymes, and glucose transporters are some of the various factors influencing the kidney's role. Patients with type 2 diabetes have an increased renal glucose uptake and release in the fasting and the post-prandial states. Additionally, glucosuria in these patients does not occur at plasma glucose levels that would normally produce glucosuria in healthy individuals. The major abnormality of renal glucose metabolism in type 1 diabetes appears to be impaired renal glucose release during hypoglycemia. Copyright © 2017 Elsevier B.V. All rights reserved.

DIRAC universal pilots

NASA Astrophysics Data System (ADS)

Stagni, F.; McNab, A.; Luzzi, C.; Krzemien, W.; Consortium, DIRAC

2017-10-01

In the last few years, new types of computing models, such as IAAS (Infrastructure as a Service) and IAAC (Infrastructure as a Client), gained popularity. New resources may come as part of pledged resources, while others are in the form of opportunistic ones. Most but not all of these new infrastructures are based on virtualization techniques. In addition, some of them, present opportunities for multi-processor computing slots to the users. Virtual Organizations are therefore facing heterogeneity of the available resources and the use of an Interware software like DIRAC to provide the transparent, uniform interface has become essential. The transparent access to the underlying resources is realized by implementing the pilot model. DIRAC’s newest generation of generic pilots (the so-called Pilots 2.0) are the “pilots for all the skies”, and have been successfully released in production more than a year ago. They use a plugin mechanism that makes them easily adaptable. Pilots 2.0 have been used for fetching and running jobs on every type of resource, being it a Worker Node (WN) behind a CREAM/ARC/HTCondor/DIRAC Computing element, a Virtual Machine running on IaaC infrastructures like Vac or BOINC, on IaaS cloud resources managed by Vcycle, the LHCb High Level Trigger farm nodes, and any type of opportunistic computing resource. Make a machine a “Pilot Machine”, and all diversities between them will disappear. This contribution describes how pilots are made suitable for different resources, and the recent steps taken towards a fully unified framework, including monitoring. Also, the cases of multi-processor computing slots either on real or virtual machines, with the whole node or a partition of it, is discussed.

Virtual reality: teaching tool of the twenty-first century?

PubMed

Hoffman, H; Vu, D

1997-12-01

Virtual reality (VR) is gaining recognition for its enormous educational potential. While not yet in the mainstream of academic medical training, many prototype and first-generation VR applications are emerging, with target audiences ranging from first- and second-year medical students to residents in advanced clinical training. Visualization tools that take advantage of VR technologies are being designed to provide engaging and intuitive environments for learning visually and spatially complex topics such as human anatomy, biochemistry, and molecular biology. These applications present dynamic, three-dimensional views of structures and their spatial relationships, enabling users to move beyond "real-world" experiences by interacting with or altering virtual objects in ways that would otherwise be difficult or impossible. VR-based procedural and surgical simulations, often compared with flight simulators in aviation, hold significant promise for revolutionizing medical training. Already a wide range of simulations, representing diverse content areas and utilizing a variety of implementation strategies, are either under development or in their early implementation stages. These new systems promise to make broad-based training experiences available for students at all levels, without the risks and ethical concerns typically associated with using animal and human subjects. Medical students could acquire proficiency and gain confidence in the ability to perform a wide variety of techniques long before they need to use them clinically. Surgical residents could rehearse and refine operative procedures, using an unlimited pool of virtual patients manifesting a wide range of anatomic variations, traumatic wounds, and disease states. Those simulated encounters, in combination with existing opportunities to work with real patients, could increase the depth and breadth of learners' exposure to medical problems, ensure uniformity of training experiences, and enhance the acquisition of clinical skills.

New Cerec software version 4.3 for Omnicam and Bluecam.

PubMed

Fritzsche, G; Schenk, O

2014-01-01

The introduction of the Cerec Omnicam acquisition unit in September 2012 presented Sirona with a challenge: con- figuring the existing software version 4 for both the exist- ing Bluecam, which uses still images, and the video-based Omnicam. Sirona has succeeded in making all the features introduced in version 4.2 (such as the virtual articulator or implant-supported single-tooth restorations, both monolithic and two-part designs) work with both camera types, without compromising the uniform, homogeneous look and feel of the software. The virtual articulator (Figs 1a to 1c) now has even more individual configuration options and allows the setting of almost all angles derived from the individual transfer bow based on precalculated average values. The new software version 4.3, presented in July 2014, fixes some minor bugs, such as the time-consuming "empty grinding" after necessary water changes during the grinding process, but also includes many features that noticeably ease the workflow. For example, the important scanning precision in the region of the anterior incisal edges has been improved, which makes the scanning process more reliable, faster, and far more comfortable.

CFD study on the effects of boundary conditions on air flow through an air-cooled condenser

NASA Astrophysics Data System (ADS)

Sumara, Zdeněk; Šochman, Michal

2018-06-01

This study focuses on the effects of boundary conditions on effectiveness of an air-cooled condenser (ACC). Heat duty of ACC is very often calculated for ideal uniform velocity field which does not correspond to reality. Therefore, this study studies the effect of wind and different landscapes on air flow through ACC. For this study software OpenFOAM was used and the flow was simulated with the use of RANS equations. For verification of numerical setup a model of one ACC cell with dimensions of platform 1.5×1.5 [m] was used. In this experiment static pressures behind fan and air flows through a model of surface of condenser for different rpm of fan were measured. In OpenFOAM software a virtual clone of this experiment was built and different meshes, turbulent models and numerical schemes were tested. After tuning up numerical setup virtual model of real ACC system was built. Influence of wind, landscape and height of ACC on air flow through ACC has been investigated.

Research on axisymmetric aspheric surface numerical design and manufacturing technology

NASA Astrophysics Data System (ADS)

Wang, Zhen-zhong; Guo, Yin-biao; Lin, Zheng

2006-02-01

The key technology for aspheric machining offers exact machining path and machining aspheric lens with high accuracy and efficiency, in spite of the development of traditional manual manufacturing into nowadays numerical control (NC) machining. This paper presents a mathematical model between virtual cone and aspheric surface equations, and discusses the technology of uniform wear of grinding wheel and error compensation in aspheric machining. Finally, a software system for high precision aspheric surface manufacturing is designed and realized, based on the mentioned above. This software system can work out grinding wheel path according to input parameters and generate machining NC programs of aspheric surfaces.

GCM simulations of cold dry Snowball Earth atmospheres

NASA Astrophysics Data System (ADS)

Voigt, A.; Held, I.; Marotzke, J.

2009-12-01

We use the full-physics atmospheric general circulation model ECHAM5 to investigate cold and virtually dry Snowball Earth atmospheres. These result from specifying sea ice as the surface boundary condition everywhere, corresponding to a frozen aquaplanet, while keeping total solar irradiance at its present-day value of 1365 Wm-2 and setting atmospheric carbon dioxide to 300 ppmv. Here, we present four simulations corresponding to the four possible combinations of enabled or disabled diurnal and seasonal cycles. The aim of this study is twofold. First, we focus on the zonal-mean circulation of Snowball Earth atmospheres, which, due to missing moisture, might constitute an ideal though yet unexplored testbed for theories of atmospheric dynamics. Second, we investigate tropical surface temperatures with an emphasis on the impact of the diurnal and seasonal cycles. This will indicate whether the presence of the diurnal or seasonal cycle would facilitate or anticipate the escape from Snowball Earth conditions when total solar irradiance or atmospheric CO2 levels were increased. The dynamics of the tropical circulation in Snowball Earth atmospheres differs substantially from that in the modern atmosphere. The analysis of the mean zonal momentum budget reveals that the mean flow meridional advection of absolute vorticity is primarily balanced by vertical diffusion of zonal momentum. The contribution of eddies is found to be even smaller than the contribution of mean flow vertical advection of zonal momentum, the latter being usually neglected in theories for the Hadley circulation, at least in its upper tropospheric branch. Suppressing vertical diffusion of horizontal momentum above 850 hPa leads to a stronger Hadley circulation. This behaviour cannot be understood from axisymmetric models of the atmosphere, nor idealized atmospheric general circulation models, which both predict a weakening of the Hadley circulation when the vertical viscosity is decreased globally. We find that enabling the diurnal cycle does not change tropical annual-mean surface temperatures but significantly strengthens the Hadley circulation, which increases by 33% for equinoctial and by 50% during solstitial insolation conditions compared to simulations without diurnal cycle. Including the seasonal cycle results in a ''reversed'' annual-mean Hadley circulation with subsiding motion at the equator and ascending motion around 15N/S, a manifestation of the extreme seasonality of Snowball Earth atmospheres due to the low thermal inertia of the sea-ice surface. The impact of the seasonal cycle on the tropical annual-mean surface is a straightforward consequence of changes in insolation distribution: as annual-mean incoming shortwave radiation at the equator reduces by 18 Wm-2 for enabled seasonal cycle, tropical annual-mean surface temperatures decrease from 221 K to 217 K.

A Simple and Rapid Method for Standard Preparation of Gas Phase Extract of Cigarette Smoke

PubMed Central

Higashi, Tsunehito; Mai, Yosuke; Noya, Yoichi; Horinouchi, Takahiro; Terada, Koji; Hoshi, Akimasa; Nepal, Prabha; Harada, Takuya; Horiguchi, Mika; Hatate, Chizuru; Kuge, Yuji; Miwa, Soichi

2014-01-01

Cigarette smoke consists of tar and gas phase: the latter is toxicologically important because it can pass through lung alveolar epithelium to enter the circulation. Here we attempt to establish a standard method for preparation of gas phase extract of cigarette smoke (CSE). CSE was prepared by continuously sucking cigarette smoke through a Cambridge filter to remove tar, followed by bubbling it into phosphate-buffered saline (PBS). An increase in dry weight of the filter was defined as tar weight. Characteristically, concentrations of CSEs were represented as virtual tar concentrations, assuming that tar on the filter was dissolved in PBS. CSEs prepared from smaller numbers of cigarettes (original tar concentrations ≤15 mg/ml) showed similar concentration-response curves for cytotoxicity versus virtual tar concentrations, but with CSEs from larger numbers (tar ≥20 mg/ml), the curves were shifted rightward. Accordingly, the cytotoxic activity was detected in PBS of the second reservoir downstream of the first one with larger numbers of cigarettes. CSEs prepared from various cigarette brands showed comparable concentration-response curves for cytotoxicity. Two types of CSEs prepared by continuous and puff smoking protocols were similar regarding concentration-response curves for cytotoxicity, pharmacology of their cytotoxicity, and concentrations of cytotoxic compounds. These data show that concentrations of CSEs expressed by virtual tar concentrations can be a reference value to normalize their cytotoxicity, irrespective of numbers of combusted cigarettes, cigarette brands and smoking protocols, if original tar concentrations are ≤15 mg/ml. PMID:25229830

Sources and pathways of the upscale effects on the Southern Hemisphere jet in MPAS-CAM4 variable-resolution simulations

DOE PAGES

Sakaguchi, Koichi; Lu, Jian; Leung, L. Ruby; ...

2016-10-22

Impacts of regional grid refinement on large-scale circulations (“upscale effects”) were detected in a previous study that used the Model for Prediction Across Scales-Atmosphere coupled to the physics parameterizations of the Community Atmosphere Model version 4. The strongest upscale effect was identified in the Southern Hemisphere jet during austral winter. This study examines the detailed underlying processes by comparing two simulations at quasi-uniform resolutions of 30 and 120 km to three variable-resolution simulations in which the horizontal grids are regionally refined to 30 km in North America, South America, or Asia from 120 km elsewhere. In all the variable-resolution simulations,more » precipitation increases in convective areas inside the high-resolution domains, as in the reference quasi-uniform high-resolution simulation. With grid refinement encompassing the tropical Americas, the increased condensational heating expands the local divergent circulations (Hadley cell) meridionally such that their descending branch is shifted poleward, which also pushes the baroclinically unstable regions, momentum flux convergence, and the eddy-driven jet poleward. This teleconnection pathway is not found in the reference high-resolution simulation due to a strong resolution sensitivity of cloud radiative forcing that dominates the aforementioned teleconnection signals. The regional refinement over Asia enhances Rossby wave sources and strengthens the upper level southerly flow, both facilitating the cross-equatorial propagation of stationary waves. Evidence indicates that this teleconnection pathway is also found in the reference high-resolution simulation. Lastly, the result underlines the intricate diagnoses needed to understand the upscale effects in global variable-resolution simulations, with implications for science investigations using the computationally efficient modeling framework.« less

Sources and pathways of the upscale effects on the Southern Hemisphere jet in MPAS-CAM4 variable-resolution simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakaguchi, Koichi; Lu, Jian; Leung, L. Ruby

Impacts of regional grid refinement on large-scale circulations (“upscale effects”) were detected in a previous study that used the Model for Prediction Across Scales-Atmosphere coupled to the physics parameterizations of the Community Atmosphere Model version 4. The strongest upscale effect was identified in the Southern Hemisphere jet during austral winter. This study examines the detailed underlying processes by comparing two simulations at quasi-uniform resolutions of 30 and 120 km to three variable-resolution simulations in which the horizontal grids are regionally refined to 30 km in North America, South America, or Asia from 120 km elsewhere. In all the variable-resolution simulations,more » precipitation increases in convective areas inside the high-resolution domains, as in the reference quasi-uniform high-resolution simulation. With grid refinement encompassing the tropical Americas, the increased condensational heating expands the local divergent circulations (Hadley cell) meridionally such that their descending branch is shifted poleward, which also pushes the baroclinically unstable regions, momentum flux convergence, and the eddy-driven jet poleward. This teleconnection pathway is not found in the reference high-resolution simulation due to a strong resolution sensitivity of cloud radiative forcing that dominates the aforementioned teleconnection signals. The regional refinement over Asia enhances Rossby wave sources and strengthens the upper level southerly flow, both facilitating the cross-equatorial propagation of stationary waves. Evidence indicates that this teleconnection pathway is also found in the reference high-resolution simulation. Lastly, the result underlines the intricate diagnoses needed to understand the upscale effects in global variable-resolution simulations, with implications for science investigations using the computationally efficient modeling framework.« less

Effect of roughness formulation on the performance of a coupled wave, hydrodynamic, and sediment transport model

USGS Publications Warehouse

Ganju, Neil K.; Sherwood, Christopher R.

2010-01-01

A variety of algorithms are available for parameterizing the hydrodynamic bottom roughness associated with grain size, saltation, bedforms, and wave–current interaction in coastal ocean models. These parameterizations give rise to spatially and temporally variable bottom-drag coefficients that ostensibly provide better representations of physical processes than uniform and constant coefficients. However, few studies have been performed to determine whether improved representation of these variable bottom roughness components translates into measurable improvements in model skill. We test the hypothesis that improved representation of variable bottom roughness improves performance with respect to near-bed circulation, bottom stresses, or turbulence dissipation. The inner shelf south of Martha’s Vineyard, Massachusetts, is the site of sorted grain-size features which exhibit sharp alongshore variations in grain size and ripple geometry over gentle bathymetric relief; this area provides a suitable testing ground for roughness parameterizations. We first establish the skill of a nested regional model for currents, waves, stresses, and turbulent quantities using a uniform and constant roughness; we then gauge model skill with various parameterization of roughness, which account for the influence of the wave-boundary layer, grain size, saltation, and rippled bedforms. We find that commonly used representations of ripple-induced roughness, when combined with a wave–current interaction routine, do not significantly improve skill for circulation, and significantly decrease skill with respect to stresses and turbulence dissipation. Ripple orientation with respect to dominant currents and ripple shape may be responsible for complicating a straightforward estimate of the roughness contribution from ripples. In addition, sediment-induced stratification may be responsible for lower stresses than predicted by the wave–current interaction model.

High Power ECR Ion Thruster Discharge Characterization

NASA Technical Reports Server (NTRS)

Foster, John E.; Kamhawi, Hani; Haag, Thomas; Carpenter, Christian; Williams, George W.

2006-01-01

Electron cyclotron resonance (ECR) based ion thrusters with carbon based ion optics can potentially satisfy lifetime requirements for long duration missions (approximately 10 years) because grid erosion and cathode insert depletion issues are virtually eliminated. Though the ECR plasma discharge has been found to typically operate at slightly higher discharge losses than conventional DC ion thrusters (for high total thruster power applications), the discharge power fraction is small (less than 1 percent at 25 kW). In this regard, the benefits of increased life, low discharge plasma potentials, and reduced complexity are welcome tradeoffs for the associated discharge efficiency decrease. Presented here are results from discharge characterization of a large area ECR plasma source for gridded ion thruster applications. These measurements included load matching efficacy, bulk plasma properties via Langmuir probe, and plasma uniformity as measured using current probes distributed at the exit plane. A high degree of plasma uniformity was observed (flatness greater than 0.9). Additionally, charge state composition was qualitatively evaluated using emission spectroscopy. Plasma induced emission was dominated by xenon ion lines. No doubly charged xenon ions were detected.

Stresses and deformations in cross-ply composite tubes subjected to a uniform temperature change: Elasticity and Approximate Solutions

NASA Technical Reports Server (NTRS)

Hyer, M. W.; Cooper, D. E.; Cohen, D.

1985-01-01

The effects of a uniform temperature change on the stresses and deformations of composite tubes are investigated. The accuracy of an approximate solution based on the principle of complementary virtual work is determined. Interest centers on tube response away from the ends and so a planar elasticity approach is used. For the approximate solution a piecewise linear variation of stresses with the radial coordinate is assumed. The results from the approximate solution are compared with the elasticity solution. The stress predictions agree well, particularly peak interlaminar stresses. Surprisingly, the axial deformations also agree well. This, despite the fact that the deformations predicted by the approximate solution do not satisfy the interface displacement continuity conditions required by the elasticity solution. The study shows that the axial thermal expansion coefficient of tubes with a specific number of axial and circumferential layers depends on the stacking sequence. This is in contrast to classical lamination theory which predicts the expansion to be independent of the stacking arrangement. As expected, the sign and magnitude of the peak interlaminar stresses depends on stacking sequence.

Modeling the Effects of Inhomogeneous Aerosols on the Hot Jupiter Kepler-7b’s Atmospheric Circulation

NASA Astrophysics Data System (ADS)

Roman, Michael; Rauscher, Emily

2017-11-01

Motivated by observational evidence of inhomogeneous clouds in exoplanetary atmospheres, we investigate how proposed simple cloud distributions can affect atmospheric circulations and infrared emission. We simulated temperatures and winds for the hot Jupiter Kepler-7b using a three-dimensional atmospheric circulation model that included a simplified aerosol radiative transfer model. We prescribed fixed cloud distributions and scattering properties based on results previously inferred from Kepler-7b optical phase curves, including inhomogeneous aerosols centered along the western terminator and hypothetical cases in which aerosols additionally extended across much of the planet’s nightside. In all cases, a strong jet capable of advecting aerosols from a cooler nightside to dayside was found to persist, but only at the equator. Colder temperatures at mid and polar latitudes might permit aerosol to form on the dayside without the need for advection. By altering the deposition and redistribution of heat, aerosols along the western terminator produced an asymmetric heating that effectively shifts the hottest spot further east of the substellar point than expected for a uniform distribution. The addition of opaque high clouds on the nightside can partly mitigate this enhanced shift by retaining heat that contributes to warming west of the hotspot. These expected differences in infrared phase curves could place constraints on proposed cloud distributions and their infrared opacities for brighter hot Jupiters.

Improved efficacy for ezetimibe and rosuvastatin by attenuating the induction of PCSK9[S

PubMed Central

Ason, Brandon; Tep, Samnang; Davis, Harry R.; Xu, Yiming; Tetzloff, Glen; Galinski, Beverly; Soriano, Ferdie; Dubinina, Natalya; Zhu, Lei; Stefanni, Alice; Wong, Kenny K.; Tadin-Strapps, Marija; Bartz, Steven R.; Hubbard, Brian; Ranalletta, Mollie; Sachs, Alan B.; Flanagan, W. Michael; Strack, Alison; Kuklin, Nelly A.

2011-01-01

Reducing circulating LDL-cholesterol (LDL-c) reduces the risk of cardiovascular disease in people with hypercholesterolemia. Current approaches to reduce circulating LDL-c include statins, which inhibit cholesterol synthesis, and ezetimibe, which blocks cholesterol absorption. Both elevate serum PCSK9 protein levels in patients, which could attenuate their efficacy by reducing the amount of cholesterol cleared from circulation. To determine whether PCSK9 inhibition could enhance LDL-c lowering of both statins and ezetimibe, we utilized small interfer­ing RNAs (siRNAs) to knock down Pcsk9, together with ezetimibe, rosuvastatin, and an ezetimibe/rosuvastatin combination in a mouse model with a human-like lipid profile. We found that ezetimibe, rosuvastatin, and ezetimibe/rosuvastatin combined lower serum cholesterol but induce the expression of Pcsk9 as well as the Srebp-2 hepatic cholesterol biosynthesis pathway. Pcsk9 knockdown in combination with either treatment led to greater reductions in serum non-HDL with a near-uniform reduction of all LDL-c subfractions. In addition to reducing serum cholesterol, the combined rosuvastatin/ezetimibe/Pcsk9 siRNA treatment exhibited a significant reduction in serum APOB protein and triglyceride levels. Taken together, these data provide evidence that PCSK9 inhibitors, in combination with current therapies, have the potential to achieve greater reductions in both serum cholesterol and triglycerides. PMID:21262787

Use of high-granularity CdZnTe pixelated detectors to correct response non-uniformities caused by defects in crystals

DOE PAGES

Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.; ...

2015-09-06

Following our successful demonstration of the position-sensitive virtual Frisch-grid detectors, we investigated the feasibility of using high-granularity position sensing to correct response non-uniformities caused by the crystal defects in CdZnTe (CZT) pixelated detectors. The development of high-granularity detectors able to correct response non-uniformities on a scale comparable to the size of electron clouds opens the opportunity of using unselected off-the-shelf CZT material, whilst still assuring high spectral resolution for the majority of the detectors fabricated from an ingot. Here, we present the results from testing 3D position-sensitive 15×15×10 mm 3 pixelated detectors, fabricated with conventional pixel patterns with progressively smallermore » pixel sizes: 1.4, 0.8, and 0.5 mm. We employed the readout system based on the H3D front-end multi-channel ASIC developed by BNL's Instrumentation Division in collaboration with the University of Michigan. We use the sharing of electron clouds among several adjacent pixels to measure locations of interaction points with sub-pixel resolution. By using the detectors with small-pixel sizes and a high probability of the charge-sharing events, we were able to improve their spectral resolutions in comparison to the baseline levels, measured for the 1.4-mm pixel size detectors with small fractions of charge-sharing events. These results demonstrate that further enhancement of the performance of CZT pixelated detectors and reduction of costs are possible by using high spatial-resolution position information of interaction points to correct the small-scale response non-uniformities caused by crystal defects present in most devices.« less

Generation of realistic virtual nodules based on three-dimensional spatial resolution in lung computed tomography: A pilot phantom study.

PubMed

Narita, Akihiro; Ohkubo, Masaki; Murao, Kohei; Matsumoto, Toru; Wada, Shinichi

2017-10-01

The aim of this feasibility study using phantoms was to propose a novel method for obtaining computer-generated realistic virtual nodules in lung computed tomography (CT). In the proposed methodology, pulmonary nodule images obtained with a CT scanner are deconvolved with the point spread function (PSF) in the scan plane and slice sensitivity profile (SSP) measured for the scanner; the resultant images are referred to as nodule-like object functions. Next, by convolving the nodule-like object function with the PSF and SSP of another (target) scanner, the virtual nodule can be generated so that it has the characteristics of the spatial resolution of the target scanner. To validate the methodology, the authors applied physical nodules of 5-, 7- and 10-mm-diameter (uniform spheres) included in a commercial CT test phantom. The nodule-like object functions were calculated from the sphere images obtained with two scanners (Scanner A and Scanner B); these functions were referred to as nodule-like object functions A and B, respectively. From these, virtual nodules were generated based on the spatial resolution of another scanner (Scanner C). By investigating the agreement of the virtual nodules generated from the nodule-like object functions A and B, the equivalence of the nodule-like object functions obtained from different scanners could be assessed. In addition, these virtual nodules were compared with the real (true) sphere images obtained with Scanner C. As a practical validation, five types of laboratory-made physical nodules with various complicated shapes and heterogeneous densities, similar to real lesions, were used. The nodule-like object functions were calculated from the images of these laboratory-made nodules obtained with Scanner A. From them, virtual nodules were generated based on the spatial resolution of Scanner C and compared with the real images of laboratory-made nodules obtained with Scanner C. Good agreement of the virtual nodules generated from the nodule-like object functions A and B of the phantom spheres was found, suggesting the validity of the nodule-like object functions. The virtual nodules generated from the nodule-like object function A of the phantom spheres were similar to the real images obtained with Scanner C; the root mean square errors (RMSEs) between them were 10.8, 11.1, and 12.5 Hounsfield units (HU) for 5-, 7-, and 10-mm-diameter spheres, respectively. The equivalent results (RMSEs) using the nodule-like object function B were 15.9, 16.8, and 16.5 HU, respectively. These RMSEs were small considering the high contrast between the sphere density and background density (approximately 674 HU). The virtual nodules generated from the nodule-like object functions of the five laboratory-made nodules were similar to the real images obtained with Scanner C; the RMSEs between them ranged from 6.2 to 8.6 HU in five cases. The nodule-like object functions calculated from real nodule images would be effective to generate realistic virtual nodules. The proposed method would be feasible for generating virtual nodules that have the characteristics of the spatial resolution of the CT system used in each institution, allowing for site-specific nodule generation. © 2017 American Association of Physicists in Medicine.

Hyperthyroidism: diagnosis and management of Graves' disease.

PubMed

Schilling, J S

1997-06-01

Hyperthyroidism, or thyrotoxicosis, results when the body's tissues are exposed to excessive levels of thyroid hormone. Hyperthyroidism affects 2% of women but only one-tenth as many men. Graves' disease is the most common form of hyperthyroidism, often occurring in young adults. It is an autoimmune disorder with an important genetic component. Hyperthyroidism's hallmarks include goiter and myriad signs and symptoms related to increased metabolic activity in virtually all body tissues. Increased sensitivity to circulating catecholamines adds to the clinical picture. Diagnosed by patient history, physical examination, and laboratory tests, Graves' disease is treated with antithyroid drugs, radioactive iodine, and/or surgery, plus supportive therapy. A good treatment outcome can be expected; long-term follow-up is indicated.

Controlling sound radiation through an opening with secondary loudspeakers along its boundaries.

PubMed

Wang, Shuping; Tao, Jiancheng; Qiu, Xiaojun

2017-10-17

We propose a virtual sound barrier system that blocks sound transmission through openings without affecting access, light and air circulation. The proposed system applies active control technique to cancel sound transmission with a double layered loudspeaker array at the edge of the opening. Unlike traditional transparent glass windows, recently invented double-glazed ventilation windows and planar active sound barriers or any other metamaterials designed to reduce sound transmission, secondary loudspeakers are put only along the boundaries of the opening, which provides the possibility to make it invisible. Simulation and experimental results demonstrate its feasibility for broadband sound control, especially for low frequency sound which is usually hard to attenuate with existing methods.

Scale up of fuel ethanol production from sugar beet juice using loofa sponge immobilized bioreactor.

PubMed

Ogbonna, J C; Mashima, H; Tanaka, H

2001-01-01

Production of fuel ethanol from sugar beet juice, using cells immobilized on loofa sponge was investigated. Based on ethanol productivity and ease of cell immobilization, a flocculating yeast strain, Saccharomyces cerevisiae IR2 was selected for ethanol production from sugar beet juice. It was found that raw sugar beet juice was an optimal substrate for ethanol production, requiring neither pH adjustment nor nitrogen source supplement. When compared with a 2 l bubble column bioreactor, mixing was not sufficient in an 8 l bioreactor containing a bed of sliced loofa sponges and consequently, the immobilized cells were not uniformly distributed within the bed. Most of the cells were immobilized in the lower part of the bed and this resulted in decreased ethanol productivity. By using an external loop bioreactor, constructing the fixed bed with cylindrical loofa sponges, dividing the bed into upper, middle and lower sections with approximately 1 cm spaces between them and circulating the broth through the loop during the immobilization, uniform cell distribution within the bed was achieved. Using this method, the system was scaled up to 50 l and when compared with the 2 l bubble column bioreactor, there were no significant differences (P > 0.05) in ethanol productivity and yield. By using external loop bioreactor to immobilize the cells uniformly on the loofa sponge beds, efficient large scale ethanol production systems can be constructed.

The sensitivity of Alpine summer convection to surrogate climate change: an intercomparison between convection-parameterizing and convection-resolving models

NASA Astrophysics Data System (ADS)

Keller, Michael; Kröner, Nico; Fuhrer, Oliver; Lüthi, Daniel; Schmidli, Juerg; Stengel, Martin; Stöckli, Reto; Schär, Christoph

2018-04-01

Climate models project an increase in heavy precipitation events in response to greenhouse gas forcing. Important elements of such events are rain showers and thunderstorms, which are poorly represented in models with parameterized convection. In this study, simulations with 12 km horizontal grid spacing (convection-parameterizing model, CPM) and 2 km grid spacing (convection-resolving model, CRM) are employed to investigate the change in the diurnal cycle of convection with warmer climate. For this purpose, simulations of 11 days in June 2007 with a pronounced diurnal cycle of convection are compared with surrogate simulations from the same period. The surrogate climate simulations mimic a future climate with increased temperatures but unchanged relative humidity and similar synoptic-scale circulation. Two temperature scenarios are compared: one with homogeneous warming (HW) using a vertically uniform warming and the other with vertically dependent warming (VW) that enables changes in lapse rate. The two sets of simulations with parameterized and explicit convection exhibit substantial differences, some of which are well known from the literature. These include differences in the timing and amplitude of the diurnal cycle of convection, and the frequency of precipitation with low intensities. The response to climate change is much less studied. We can show that stratification changes have a strong influence on the changes in convection. Precipitation is strongly increasing for HW but decreasing for the VW simulations. For cloud type frequencies, virtually no changes are found for HW, but a substantial reduction in high clouds is found for VW. Further, we can show that the climate change signal strongly depends upon the horizontal resolution. In particular, significant differences between CPM and CRM are found in terms of the radiative feedbacks, with CRM exhibiting a stronger negative feedback in the top-of-the-atmosphere energy budget.

Blood transcriptomic comparison of individuals with and without autism spectrum disorder: A combined-samples mega-analysis.

PubMed

Tylee, Daniel S; Hess, Jonathan L; Quinn, Thomas P; Barve, Rahul; Huang, Hailiang; Zhang-James, Yanli; Chang, Jeffrey; Stamova, Boryana S; Sharp, Frank R; Hertz-Picciotto, Irva; Faraone, Stephen V; Kong, Sek Won; Glatt, Stephen J

2017-04-01

Blood-based microarray studies comparing individuals affected with autism spectrum disorder (ASD) and typically developing individuals help characterize differences in circulating immune cell functions and offer potential biomarker signal. We sought to combine the subject-level data from previously published studies by mega-analysis to increase the statistical power. We identified studies that compared ex vivo blood or lymphocytes from ASD-affected individuals and unrelated comparison subjects using Affymetrix or Illumina array platforms. Raw microarray data and clinical meta-data were obtained from seven studies, totaling 626 affected and 447 comparison subjects. Microarray data were processed using uniform methods. Covariate-controlled mixed-effect linear models were used to identify gene transcripts and co-expression network modules that were significantly associated with diagnostic status. Permutation-based gene-set analysis was used to identify functionally related sets of genes that were over- and under-expressed among ASD samples. Our results were consistent with diminished interferon-, EGF-, PDGF-, PI3K-AKT-mTOR-, and RAS-MAPK-signaling cascades, and increased ribosomal translation and NK-cell related activity in ASD. We explored evidence for sex-differences in the ASD-related transcriptomic signature. We also demonstrated that machine-learning classifiers using blood transcriptome data perform with moderate accuracy when data are combined across studies. Comparing our results with those from blood-based studies of protein biomarkers (e.g., cytokines and trophic factors), we propose that ASD may feature decoupling between certain circulating signaling proteins (higher in ASD samples) and the transcriptional cascades which they typically elicit within circulating immune cells (lower in ASD samples). These findings provide insight into ASD-related transcriptional differences in circulating immune cells. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Blood Transcriptomic Comparison of Individuals with and without Autism Spectrum Disorder: A Combined-Samples Mega-Analysis

PubMed Central

Tylee, Daniel S.; Hess, Jonathan L.; Quinn, Thomas P.; Barve, Rahul; Huang, Hailiang; Zhang-James, Yanli; Chang, Jeffrey; Stamova, Boryana S.; Sharp, Frank R.; Hertz-Picciotto, Irva; Faraone, Stephen V.; Kong, Sek Won; Glatt, Stephen J.

2017-01-01

Blood-based microarray studies comparing individuals affected with autism spectrum disorder (ASD) and typically developing individuals help characterize differences in circulating immune cell functions and offer potential biomarker signal. We sought to combine the subject-level data from previously published studies by mega-analysis to increase the statistical power. We identified studies that compared ex-vivo blood or lymphocytes from ASD-affected individuals and unrelated comparison subjects using Affymetrix or Illumina array platforms. Raw microarray data and clinical meta-data were obtained from seven studies, totaling 626 affected and 447 comparison subjects. Microarray data were processed using uniform methods. Covariate-controlled mixed-effect linear models were used to identify gene transcripts and co-expression network modules that were significantly associated with diagnostic status. Permutation-based gene-set analysis was used to identify functionally related sets of genes that were over- and under-expressed among ASD samples. Our results were consistent with diminished interferon-, EGF-, PDGF-, PI3K-AKT-mTOR-, and RAS-MAPK-signaling cascades, and increased ribosomal translation and NK-cell related activity in ASD. We explored evidence for sex-differences in the ASD-related transcriptomic signature. We also demonstrated that machine-learning classifiers using blood transcriptome data perform with moderate accuracy when data are combined across studies. Comparing our results with those from blood-based studies of protein biomarkers (e.g., cytokines and trophic factors), we propose that ASD may feature decoupling between certain circulating signaling proteins (higher in ASD samples) and the transcriptional cascades which they typically elicit within circulating immune cells (lower in ASD samples). These findings provide insight into ASD-related transcriptional differences in circulating immune cells. PMID:27862943

Emergy evaluation of water utilization benefits in water-ecological-economic system based on water cycle process

NASA Astrophysics Data System (ADS)

Guo, X.; Wu, Z.; Lv, C.

2017-12-01

The water utilization benefits are formed by the material flow, energy flow, information flow and value stream in the whole water cycle process, and reflected along with the material circulation of inner system. But most of traditional water utilization benefits evaluation are based on the macro level, only consider the whole material input and output and energy conversion relation, and lack the characterization of water utilization benefits accompanying with water cycle process from the formation mechanism. In addition, most studies are from the perspective of economics, only pay attention to the whole economic output and sewage treatment economic investment, but neglect the ecological function benefits of water cycle, Therefore, from the perspective of internal material circulation in the whole system, taking water cycle process as the process of material circulation and energy flow, the circulation and flow process of water and other ecological environment, social economic elements were described, and the composition of water utilization positive and negative benefits in water-ecological-economic system was explored, and the performance of each benefit was analyzed. On this basis, the emergy calculation method of each benefit was proposed by emergy quantitative analysis technique, which can realize the unified measurement and evaluation of water utilization benefits in water-ecological-economic system. Then, taking Zhengzhou city as an example, the corresponding benefits of different water cycle links were calculated quantitatively by emergy method, and the results showed that the emergy evaluation method of water utilization benefits can unify the ecosystem and the economic system, achieve uniform quantitative analysis, and measure the true value of natural resources and human economic activities comprehensively.

GATE Monte Carlo simulation of GE Discovery 600 and a uniformity phantom

NASA Astrophysics Data System (ADS)

Sheen, Heesoon; Im, Ki Chun; Choi, Yong; Shin, Hanback; Han, Youngyih; Chung, Kwangzoo; Cho, Junsang; Ahn, Sang Hee

2014-12-01

GATE (Geant4 Application Tomography Emission) Monte Carlo simulations have been successful in the application of emission tomography for precise modeling of various physical processes. Most previous studies on Monte Carlo simulations have only involved performance assessments using virtual phantoms. Although that allows the performance of simulated positron emission tomography (PET) to be evaluated, it does not reflect the reality of practical conditions. This restriction causes substantial drawbacks in GATE simulations of real situations. To overcome the described limitation and to provide a method to enable simulation research relevant to clinically important issues, we conducted a GATE simulation using real data from a scanner rather than a virtual phantom and evaluated the scanner is performance. For that purpose, the system and the geometry of a commercial GE PET/ CT (computed tomography) scanner, BGO-based Discovery 600 (D600), was developed for the first time. The performance of the modeled PET system was evaluated by using the National Electrical Manufacturers Association NEMA NU 2-2007 protocols and results were compared with those of the reference data. The sensitivity, scatter fraction, noise-equivalent count rate (NECR), and resolution were estimated by using the protocol of the NEMA NU2-2007. Sensitivities were 9.01 cps/kBq at 0 cm and 9.43 cps/kBq at 10 cm. Scatter fractions were 39.5%. The NECR peak was 89.7 kcps @ 14.7 kBq/cc. Resolutions were 4.8 mm in the transaxial plane and 5.9 mm in the axial plane at 1 cm, and 6.2 mm in the transaxial plane and 6.4 mm in the axial plane at 10 cm. The resolutions exceeded the limited value provided by the manufacturer. The uniformity phantom was simulated using the CT and the PET data. The output data in a ROOT format were converted and then reconstructed by using the C program and STIR (Software for Tomographic Image Reconstruction). The reconstructed images of the simulated uniformity phantom data had comparable quality even though improvement in the quality is still required. In conclusion, we have demonstrated a successful simulation of a PET system by using scanned data. In future studies, the parameters that alter the imaging conditions, such as patient movement and physiological change, need to be studied.

Layered growth with bottom-spray granulation for spray deposition of drug.

PubMed

Er, Dawn Z L; Liew, Celine V; Heng, Paul W S

2009-07-30

The gap in scientific knowledge on bottom-spray fluidized bed granulation has emphasized the need for more studies in this area. This paper comparatively studied the applicability of a modified bottom-spray process and the conventional top-spray process for the spray deposition of a micronized drug during granulation. The differences in circulation pattern, mode of growth and resultant granule properties between the two processes were highlighted. The more ordered and consistent circulation pattern of particles in a bottom-spray fluidized bed was observed to give rise to layered granule growth. This resulted in better drug content uniformity among the granule batches and within a granule batch. The processes' sensitivities to wetting and feed material characteristics were also compared and found to differ markedly. Less robustness to differing process conditions was observed for the top-spray process. The resultant bottom-spray granules formed were observed to be less porous, more spherical and had good flow properties. The bottom-spray technique can thus be potentially applied for the spray deposition of drug during granulation and was observed to be a good alternative to the conventional technique for preparing granules.

Shape Engineering Boosts Magnetic Mesoporous Silica Nanoparticle-Based Isolation and Detection of Circulating Tumor Cells.

PubMed

Chang, Zhi-Min; Wang, Zheng; Shao, Dan; Yue, Juan; Xing, Hao; Li, Li; Ge, Mingfeng; Li, Mingqiang; Yan, Huize; Hu, Hanze; Xu, Qiaobing; Dong, Wen-Fei

2018-04-04

Magnetic mesoporous silica nanoparticles (M-MSNs) are attractive candidates for the immunomagnetic isolation and detection of circulating tumor cells (CTCs). Understanding of the interactions between the effects of the shape of M-MSNs and CTCs is crucial to maximize the binding capacity and capture efficiency as well as to facilitate the sensitivity and efficiency of detection. In this work, fluorescent M-MSNs were rationally designed with sphere and rod morphologies while retaining their robust fluorescence and uniform surface functionality. After conjugation with the antibody of epithelial cell adhesion molecule (EpCAM), both of the differently shaped M-MSNs-EpCAM obtained achieved efficient enrichment of CTCs and fluorescent-based detection. Importantly, rodlike M-MSNs exhibited faster immunomagnetic isolation as well as better performance in the isolation and detection of CTCs in spiked cells and real clinical blood samples than those of their spherelike counterparts. Our results showed that shape engineering contributes positively toward immunomagnetic isolation, which might open new avenues to the rational design of magnetic-fluorescent nanoprobes for the sensitive and efficient isolation and detection of CTCs.

Detecting Trends in Tropical Rainfall Characteristics, 1979-2003

NASA Technical Reports Server (NTRS)

Lau, K. M.; Wu, H. T.

2006-01-01

From analyses of blended space-based and ground-based global rainfall data, we found increasing trends in the occurrence of extreme heavy and light rain events, coupled to a decreasing trend in moderate rain events in the tropics during 1979-2003. The trends are consistent with a shift in the large-scale circulation associated with a) a relatively uniform increase in warm rain over the tropical oceans, b) enhanced ice-phase rain over the near-equatorial oceans, and c) reduced mixed-phase rain over the tropical ocean and land regions. Due to the large compensation among different rain categories, the total tropical rainfall trend remained undetectable.

The nonuniformity of antibody distribution in the kidney and its influence on dosimetry.

PubMed

Flynn, Aiden A; Pedley, R Barbara; Green, Alan J; Dearling, Jason L; El-Emir, Ethaar; Boxer, Geoffrey M; Boden, Robert; Begent, Richard H J

2003-02-01

The therapeutic efficacy of radiolabeled antibody fragments can be limited by nephrotoxicity, particularly when the kidney is the major route of extraction from the circulation. Conventional dose estimates in kidney assume uniform dose deposition, but we have shown increased antibody localization in the cortex after glomerular filtration. The purpose of this study was to measure the radioactivity in cortex relative to medulla for a range of antibodies and to assess the validity of the assumption of uniformity of dose deposition in the whole kidney and in the cortex for these antibodies with a range of radionuclides. Storage phosphor plate technology (radioluminography) was used to acquire images of the distributions of a range of antibodies of various sizes, labeled with 125I, in kidney sections. This allowed the calculation of the antibody concentration in the cortex relative to the medulla. Beta-particle point dose kernels were then used to generate the dose-rate distributions from 14C, 131I, 186Re, 32P and 90Y. The correlation between the actual dose-rate distribution and the corresponding distribution calculated assuming uniform antibody distribution throughout the kidney was used to test the validity of estimating dose by assuming uniformity in the kidney and in the cortex. There was a strong inverse relationship between the ratio of the radioactivity in the cortex relative to that in the medulla and the antibody size. The nonuniformity of dose deposition was greatest with the smallest antibody fragments but became more uniform as the range of the emissions from the radionuclide increased. Furthermore, there was a strong correlation between the actual dose-rate distribution and the distribution when assuming a uniform source in the kidney for intact antibodies along with medium- to long-range radionuclides, but there was no correlation for small antibody fragments with any radioisotope or for short-range radionuclides with any antibody. However, when the cortex was separated from the whole kidney, the correlation between the actual dose-rate distribution and the assumed dose-rate distribution, if the source was uniform, increased significantly. During radioimmunotherapy, the extent of nonuniformity of dose deposition in the kidney depends on the properties of the antibody and radionuclide. For dosimetry estimates, the cortex should be taken as a separate source region when the radiopharmaceutical is small enough to be filtered by the glomerulus.

Design and fabrication of a radiative actively cooled honeycomb sandwich structural panel for a hypersonic aircraft

NASA Technical Reports Server (NTRS)

Ellis, D. A.; Pagel, L. L.; Schaeffer, D. M.

1978-01-01

The panel assembly consisted of an external thermal protection system (metallic heat shields and insulation blankets) and an aluminum honeycomb structure. The structure was cooled to temperature 442K (300 F) by circulating a 60/40 mass solution of ethylene glycol and water through dee shaped coolant tubes nested in the honeycomb and adhesively bonded to the outer skin. Rene'41 heat shields were designed to sustain 5000 cycles of a uniform pressure of + or - 6.89kPa (+ or - 1.0 psi) and aerodynamic heating conditions equivalent to 136 kW sq m (12 Btu sq ft sec) to a 422K (300 F) surface temperature. High temperature flexible insulation blankets were encased in stainless steel foil to protect them from moisture and other potential contaminates. The aluminum actively cooled honeycomb sandwich structural panel was designed to sustain 5000 cycles of cyclic in-plane loading of + or - 210 kN/m (+ or - 1200 lbf/in.) combined with a uniform panel pressure of + or - 6.89 kPa (?1.0 psi).

Heat Transfer Coefficient Distribution in the Furnace of a 300MWe CFB Boiler

NASA Astrophysics Data System (ADS)

Zhang, P.; Lu, J. F.; Yang, H. R.; Zhang, J. S.; Zhang, H.; Yue, G. X.

Properly understanding and calculating the distributions of heat flux and heat transfer coefficient (α) in the furnace is important in designing a circulating fluidized bed (CFB) boiler, especially with supercritical parameters. Experimental study on the heat transfer in a commercial 300MWe CFB boiler was conducted. The α from the bed to the water wall was measured by the finite element method (FEM), at five different heights. The influence of suspension density and bed temperature on α was analyzed. It was found that the pressure difference between the inlet and exit of the three cyclones, and the chamber pressure of the corresponding loop seal were not equal. The results indicated the suspension solid density was non-uniform in the cross section at a certain height. Consequently, the distributions of heat flux and α in the horizontal plane in the furnace was non-uniform. The furnace can divided into three sections according to the arrangement of the platen superheaters hanging in the upper CFB furnace. In each section, the heat flux near the center showed increasing trend.

Anomalously Strong and Rapid Drying of the Tropical Lower Stratosphere in 2016: Connections to Both the QBO and ENSO

NASA Astrophysics Data System (ADS)

Hurst, D. F.; Davis, S. M.; Rosenlof, K. H.; Lambert, A.; Read, W. G.; Hall, E.; Jordan, A. F.

2017-12-01

Variations in tropical lower stratospheric water vapor are generally attributable to annual cycles in the Brewer-Dobson circulation and inter-annual phenomenon like the quasi-biennial oscillation (QBO) and the El Niño Southern Oscillation (ENSO). Extremes in tropical lower stratospheric water vapor (SWV) occur when these annual and inter-annual changes are constructively superimposed. The atypical progression of the 2015-16 QBO led to a strong and rapid cooling of the tropical lower stratosphere during 2016. From December 2015 to November 2016, monthly tropical mean (15°S-15°N) coldpoint temperature (CPT) anomalies decreased 3.2°C, from 1.1 to -2.1°C. Accordingly, monthly tropical mean SWV anomalies at 83 hPa dropped 1.9 ppm, from 0.85 to -1.05 ppm. This decline in SWV anomalies is equivalent to 40% of the long-term December average tropical abundance of SWV at 83 hPa. The 2016 decreases in tropical anomalies of both CPTs and SWV were not zonally uniform, with average Eastern Hemisphere reductions greater by 2°C and 0.9 ppm (50%), respectively. Since the QBO typically has a zonally uniform effect on tropical CPTs, this implies a zonally non-uniform mechanism like ENSO also influenced CPTs during 2016. The transition of ENSO from strong El Niño to weak La Niña conditions in 2016 would induce this zonal non-uniformity by shifting convective activity from the Eastern Pacific to the Western Pacific and Indian Ocean regions. Evidence indicates the simultaneous cooling of tropical CPTs by both the QBO and ENSO during 2016 rapidly dried the tropical lower stratosphere with anomalous strength, especially in the Eastern Hemisphere.

Tumor heterogeneity measured on F-18 fluorodeoxyglucose positron emission tomography/computed tomography combined with plasma Epstein-Barr Virus load predicts prognosis in patients with primary nasopharyngeal carcinoma.

PubMed

Chan, Sheng-Chieh; Chang, Kai-Ping; Fang, Yu-Hua Dean; Tsang, Ngan-Ming; Ng, Shu-Hang; Hsu, Cheng-Lung; Liao, Chun-Ta; Yen, Tzu-Chen

2017-01-01

Plasma Epstein-Barr virus (EBV) DNA concentrations predict prognosis in patients with nasopharyngeal carcinoma (NPC). Recent evidence also indicates that intratumor heterogeneity on F-18 fluorodeoxyglucose positron emission tomography ( 18 F-FDG PET) scans is predictive of treatment outcomes in different solid malignancies. Here, we sought to investigate the prognostic value of heterogeneity parameters in patients with primary NPC. Retrospective cohort study. We examined 101 patients with primary NPC who underwent pretreatment 18 F-FDG PET/computed tomography. Circulating levels of EBV DNA were measured in all participants. The following PET heterogeneity parameters were collected: histogram-based heterogeneity parameters, second-order texture features (uniformity, contrast, entropy, homogeneity, dissimilarity, inverse difference moment), and higher-order (coarseness, contrast, busyness, complexity, strength) texture features. The median follow-up time was 5.14 years. Total lesion glycolysis (TLG), tumor heterogeneity measured by histogram-based parameter skewness, and the majority of second-order or higher-order texture features were significantly associated with overall survival (OS) and/or recurrence-free survival (RFS). In multivariate analysis, age (P =.005), EBV DNA load (P = .0002), and uniformity (P = .001) independently predicted OS. Only skewness retained the independent prognostic significance for RFS. Tumor stage, standardized uptake value, or TLG did not show an independent association with survival endpoints. The combination of uniformity, EBV DNA load, and age resulted in a more reliable prognostic stratification (P < .001). Tumor heterogeneity is superior to traditional PET parameters for predicting outcomes in primary NPC. The combination of uniformity with EBV DNA load can improve prognostic stratification in this clinical entity. 4 Laryngoscope, 127:E22-E28, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Formation Control for Water-Jet USV Based on Bio-Inspired Method

NASA Astrophysics Data System (ADS)

Fu, Ming-yu; Wang, Duan-song; Wang, Cheng-long

2018-03-01

The formation control problem for underactuated unmanned surface vehicles (USVs) is addressed by a distributed strategy based on virtual leader strategy. The control system takes account of disturbance induced by external environment. With the coordinate transformation, the advantage of the proposed scheme is that the control point can be any point of the ship instead of the center of gravity. By introducing bio-inspired model, the formation control problem is addressed with backstepping method. This avoids complicated computation, simplifies the control law, and smoothes the input signals. The system uniform ultimate boundness is proven by Lyapunov stability theory with Young inequality. Simulation results are presented to verify the effectiveness and robust of the proposed controller.

Horizontal convection with mechanical stirring

NASA Astrophysics Data System (ADS)

Griffiths, Ross; Stewart, Kial; Hughes, Graham

2012-11-01

The effects of turbulent mixing on convective circulation forced by a horizontal gradient of buoyancy at the surface is examined using laboratory experiments in which a salt flux is introduced at the surface, at one end of a box, and a freshwater buoyancy condition is applied over the rest of the surface. Horizontal rods are oscillated and yo-yoed continuously through the water column, providing a diffusivity that can be calibrated. The convection reaches a stationary state having zero net salt flux. We find that for small stirring rates the small but finite volume flux from the dense source is significant and a virtual source correction is required to take this into account. The density stratification and overturning volume transport are consistent with a theoretical model for high Rayleigh numbers: the transport ψ increases with diffusivity κ (ψg ~ gκ 1 / 4) . The results show that vertical mixing in the boundary layer is important, particularly in setting the density of the interior and the overturning rate. However, interior mixing is unimportant, which raises an interesting question over whether abyssal mixing rates in the ocean play any significant role in setting the abyssal ocean density or the transport in the Meridional Overturning Circulation.

Re-evaluating the functional landscape of the cardiovascular system during development

PubMed Central

Takada, Norio; Omae, Madoka; Sagawa, Fumihiko; Chi, Neil C.; Endo, Satsuki; Kozawa, Satoshi

2017-01-01

ABSTRACT The cardiovascular system facilitates body-wide distribution of oxygen, a vital process for the development and survival of virtually all vertebrates. However, the zebrafish, a vertebrate model organism, appears to form organs and survive mid-larval periods without a functional cardiovascular system. Despite such dispensability, it is the first organ to develop. Such enigma prompted us to hypothesize other cardiovascular functions that are important for developmental and/or physiological processes. Hence, systematic cellular ablations and functional perturbations were performed on the zebrafish cardiovascular system to gain comprehensive and body-wide understanding of such functions and to elucidate the underlying mechanisms. This approach identifies a set of organ-specific genes, each implicated for important functions. The study also unveils distinct cardiovascular mechanisms, each differentially regulating their expressions in organ-specific and oxygen-independent manners. Such mechanisms are mediated by organ-vessel interactions, circulation-dependent signals, and circulation-independent beating-heart-derived signals. A comprehensive and body-wide functional landscape of the cardiovascular system reported herein may provide clues as to why it is the first organ to develop. Furthermore, these data could serve as a resource for the study of organ development and function. PMID:28982700

Re-evaluating the functional landscape of the cardiovascular system during development.

PubMed

Takada, Norio; Omae, Madoka; Sagawa, Fumihiko; Chi, Neil C; Endo, Satsuki; Kozawa, Satoshi; Sato, Thomas N

2017-11-15

The cardiovascular system facilitates body-wide distribution of oxygen, a vital process for the development and survival of virtually all vertebrates. However, the zebrafish, a vertebrate model organism, appears to form organs and survive mid-larval periods without a functional cardiovascular system. Despite such dispensability, it is the first organ to develop. Such enigma prompted us to hypothesize other cardiovascular functions that are important for developmental and/or physiological processes. Hence, systematic cellular ablations and functional perturbations were performed on the zebrafish cardiovascular system to gain comprehensive and body-wide understanding of such functions and to elucidate the underlying mechanisms. This approach identifies a set of organ-specific genes, each implicated for important functions. The study also unveils distinct cardiovascular mechanisms, each differentially regulating their expressions in organ-specific and oxygen-independent manners. Such mechanisms are mediated by organ-vessel interactions, circulation-dependent signals, and circulation-independent beating-heart-derived signals. A comprehensive and body-wide functional landscape of the cardiovascular system reported herein may provide clues as to why it is the first organ to develop. Furthermore, these data could serve as a resource for the study of organ development and function. © 2017. Published by The Company of Biologists Ltd.

Determination of a quantitative relationship between hepatic CYP3A5*1/*3 and CYP3A4 expression for use in the prediction of metabolic clearance in virtual populations.

PubMed

Barter, Z E; Perrett, H F; Yeo, K Rowland; Allorge, D; Lennard, M S; Rostami-Hodjegan, A

2010-11-01

The creation of virtual populations allows the estimation of pharmacokinetic parameters, such as metabolic clearance in extreme individuals rather than the 'average human'. Prediction of variability in metabolic clearance within genetically diverse populations relies on understanding the covariation in the expression of enzymes. A number of statistically significant positive correlations have been observed in the hepatic expression of cytochrome P450 drug metabolising enzymes. However, these rarely provided a quantitative description of the relationships which is required in creating virtual populations. Collation of data from 40 human liver microsomal samples in the current study indicated a significant positive relationship between hepatic microsomal CYP3A5*1/*3 and CYP3A4 content. Having developed a model describing the relationship between hepatic CYP3A4 and CYP3A5*1/*3, the Simcyp Population-based Simulator(®) was used to investigate the consequences of either incorporating or ignoring the relationship between the two enzymes on estimates of drug clearance. Simulations indicated that for a compound with greater metabolism by CYP3A5 than CYP3A4, such as tacrolimus, incorporation of the correlation between CYP3A4 and CYP3A5 does have an impact on the prediction of oral clearance. Failure to consider the relationship between CYP3A4 and CYP3A5 when creating the virtual population led to a 32% lower estimate of oral clearance in individuals possessing both the CYP3A5*1/*3 genotype and high basal concentrations of CYP3A4. Potential clinical implications may include an inadequate dose estimation during clinical study design, the consequences of which may include organ rejection in transplant recipients using immunosuppressants such as tacrolimus or toxicity due to elevated concentrations of circulating metabolites. Copyright © 2010 John Wiley & Sons, Ltd.

Th17/T regulator cell balance and NK cell numbers in relation to psychosis liability and social stress reactivity.

PubMed

Counotte, J; Drexhage, H A; Wijkhuijs, J M; Pot-Kolder, R; Bergink, V; Hoek, H W; Veling, W

2018-03-01

Psychotic disorders are characterized by a deranged immune system, including altered number and function of Natural Killer (NK) and T cells. Psychotic disorders arise from an interaction between genetic vulnerability and exposure to environmental risk factors. Exposure to social adversity during early life is particularly relevant to psychosis risk and is thought to increase reactivity to subsequent minor daily social stressors. Virtual reality allows controlled experimental exposure to virtual social stressors. To investigate the interplay between social adversity during early life, cell numbers of NK cells and T helper subsets and social stress reactivity in relation to psychosis liability. Circulating numbers of Th1, Th2, Th17, T regulator and NK cells were determined using flow cytometry in 80 participants with low psychosis liability (46 healthy controls and 34 siblings) and 53 participants with high psychosis liability (14 ultra-high risk (UHR) patients and 39 recent-onset psychosis patients), with and without the experience of childhood trauma. We examined if cell numbers predicted subjective stress when participants were exposed to social stressors (crowdedness, hostility and being part of an ethnic minority) in a virtual reality environment. There were no significant group differences in Th1, Th2, Th17, T regulator and NK cell numbers between groups with a high or low liability for psychosis. However, in the high psychosis liability group, childhood trauma was associated with increased Th17 cell numbers (p = 0.028). Moreover, in the high psychosis liability group increased T regulator and decreased NK cell numbers predicted stress experience during exposure to virtual social stressors (p = 0.015 and p = 0.009 for T regulator and NK cells, respectively). A deranged Th17/T regulator balance and a reduced NK cell number are associated intermediate biological factors in the relation childhood trauma, psychosis liability and social stress reactivity. Copyright © 2018 Elsevier Inc. All rights reserved.

New, Virtually Wall-less Cannulas Designed for Augmented Venous Drainage in Minimally Invasive Cardiac Surgery.

PubMed

von Segesser, Ludwig Karl; Berdajs, Denis; Abdel-Sayed, Saad; Tozzi, Piergiorgio; Ferrari, Enrico; Maisano, Francesco

2016-01-01

Inadequate venous drainage during minimally invasive cardiac surgery becomes most evident when the blood trapped in the pulmonary circulation floods the surgical field. The present study was designed to assess the in vivo performance of new, thinner, virtually wall-less, venous cannulas designed for augmented venous drainage in comparison to traditional thin-wall cannulas. Remote cannulation was realized in 5 bovine experiments (74.0 ± 2.4 kg) with percutaneous venous access over the wire, serial dilation up to 18 F and insertion of either traditional 19 F thin wall, wire-wound cannulas, or through the same access channel, new, thinner, virtually wall-less, braided cannulas designed for augmented venous drainage. A standard minimal extracorporeal circuit set with a centrifugal pump and a hollow fiber membrane oxygenator, but no in-line reservoir was used. One hundred fifty pairs of pump-flow and required pump inlet pressure values were recorded with calibrated pressure transducers and a flowmeter calibrated by a volumetric tank and timer at increasing pump speed from 1500 RPM to 3500 RPM (500-RPM increments). Pump flow accounted for 1.73 ± 0.85 l/min for wall-less versus 1.17 ± 0.45 l/min for thin wall at 1500 RPM, 3.91 ± 0.86 versus 3.23 ± 0.66 at 2500 RPM, 5.82 ± 1.05 versus 4.96 ± 0.81 at 3500 RPM. Pump inlet pressure accounted for 9.6 ± 9.7 mm Hg versus 4.2 ± 18.8 mm Hg for 1500 RPM, -42.4 ± 26.7 versus -123 ± 51.1 at 2500 RPM, and -126.7 ± 55.3 versus -313 ± 116.7 for 3500 RPM. At the well-accepted pump inlet pressure of -80 mm Hg, the new, thinner, virtually wall-less, braided cannulas provide unmatched venous drainage in vivo. Early clinical analyses have confirmed these findings.

Exploring the impacts of physics and resolution on aqua-planet simulations from a nonhydrostatic global variable-resolution modeling framework: IMPACTS OF PHYSICS AND RESOLUTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Chun; Leung, L. Ruby; Park, Sang-Hun

Advances in computing resources are gradually moving regional and global numerical forecasting simulations towards sub-10 km resolution, but global high resolution climate simulations remain a challenge. The non-hydrostatic Model for Prediction Across Scales (MPAS) provides a global framework to achieve very high resolution using regional mesh refinement. Previous studies using the hydrostatic version of MPAS (H-MPAS) with the physics parameterizations of Community Atmosphere Model version 4 (CAM4) found notable resolution dependent behaviors. This study revisits the resolution sensitivity using the non-hydrostatic version of MPAS (NH-MPAS) with both CAM4 and CAM5 physics. A series of aqua-planet simulations at global quasi-uniform resolutionsmore » ranging from 240 km to 30 km and global variable resolution simulations with a regional mesh refinement of 30 km resolution over the tropics are analyzed, with a primary focus on the distinct characteristics of NH-MPAS in simulating precipitation, clouds, and large-scale circulation features compared to H-MPAS-CAM4. The resolution sensitivity of total precipitation and column integrated moisture in NH-MPAS is smaller than that in H-MPAS-CAM4. This contributes importantly to the reduced resolution sensitivity of large-scale circulation features such as the inter-tropical convergence zone and Hadley circulation in NH-MPAS compared to H-MPAS. In addition, NH-MPAS shows almost no resolution sensitivity in the simulated westerly jet, in contrast to the obvious poleward shift in H-MPAS with increasing resolution, which is partly explained by differences in the hyperdiffusion coefficients used in the two models that influence wave activity. With the reduced resolution sensitivity, simulations in the refined region of the NH-MPAS global variable resolution configuration exhibit zonally symmetric features that are more comparable to the quasi-uniform high-resolution simulations than those from H-MPAS that displays zonal asymmetry in simulations inside the refined region. Overall, NH-MPAS with CAM5 physics shows less resolution sensitivity compared to CAM4. These results provide a reference for future studies to further explore the use of NH-MPAS for high-resolution climate simulations in idealized and realistic configurations.« less

Grid Application Meta-Repository System: Repository Interconnectivity and Cross-domain Application Usage in Distributed Computing Environments

NASA Astrophysics Data System (ADS)

Tudose, Alexandru; Terstyansky, Gabor; Kacsuk, Peter; Winter, Stephen

Grid Application Repositories vary greatly in terms of access interface, security system, implementation technology, communication protocols and repository model. This diversity has become a significant limitation in terms of interoperability and inter-repository access. This paper presents the Grid Application Meta-Repository System (GAMRS) as a solution that offers better options for the management of Grid applications. GAMRS proposes a generic repository architecture, which allows any Grid Application Repository (GAR) to be connected to the system independent of their underlying technology. It also presents applications in a uniform manner and makes applications from all connected repositories visible to web search engines, OGSI/WSRF Grid Services and other OAI (Open Archive Initiative)-compliant repositories. GAMRS can also function as a repository in its own right and can store applications under a new repository model. With the help of this model, applications can be presented as embedded in virtual machines (VM) and therefore they can be run in their native environments and can easily be deployed on virtualized infrastructures allowing interoperability with new generation technologies such as cloud computing, application-on-demand, automatic service/application deployments and automatic VM generation.

Three-dimensional printing in cardiology: Current applications and future challenges.

PubMed

Luo, Hongxing; Meyer-Szary, Jarosław; Wang, Zhongmin; Sabiniewicz, Robert; Liu, Yuhao

2017-01-01

Three-dimensional (3D) printing has attracted a huge interest in recent years. Broadly speaking, it refers to the technology which converts a predesigned virtual model to a touchable object. In clinical medicine, it usually converts a series of two-dimensional medical images acquired through computed tomography, magnetic resonance imaging or 3D echocardiography into a physical model. Medical 3D printing consists of three main steps: image acquisition, virtual reconstruction and 3D manufacturing. It is a promising tool for preoperative evaluation, medical device design, hemodynamic simulation and medical education, it is also likely to reduce operative risk and increase operative success. However, the most relevant studies are case reports or series which are underpowered in testing its actual effect on patient outcomes. The decision of making a 3D cardiac model may seem arbitrary since it is mostly based on a cardiologist's perceived difficulty in performing an interventional procedure. A uniform consensus is urgently necessary to standardize the key steps of 3D printing from imaging acquisition to final production. In the future, more clinical trials of rigorous design are possible to further validate the effect of 3D printing on the treatment of cardiovascular diseases. (Cardiol J 2017; 24, 4: 436-444).

Effect of diesel leakage in circulating cooling water system on preponderant bacteria diversity and bactericidal effect of biocides.

PubMed

Zhong, Huiyun; Liu, Fang; Lu, Jinjin; Yang, Wei; Zhao, Chaocheng

2015-01-01

Petroleum products leakage results in adverse effect on the normal operation of a circulating cooling water system. However, relatively little research has been done to explore the effect of petroleum products leakage on circulating cooling water quality and biofilm preponderant bacteria diversity. Also, normal biocides application modes cannot fulfil the need for biofilm control. In this study, diesel oil was used as the experimental subject representing leaking petroleum products; the effect of diesel addition on biofilm preponderant bacteria diversity and the bactericidal effect of chlorine dioxide and tetradecyl dimethyl benzyl ammonium chloride (1427) was investigated. Bacterial community structures were examined by PCR-denaturing gradient gel electrophoresis and PCR cloning of 16S rDNA genes. Except for 100 mg/L diesel, increasing diesel concentration enhanced the biofilm detachment ratio compared with the control test. The microstructure of biofilm samples with 0, 300 and 900 mg/L diesel addition was observed. The species of preponderant bacteria in the biofilm sample with 300 mg/L diesel addition were more and the bacterial distribution was more uniform than those in the biofilm sample with 900 mg/L diesel addition. With ClO2 and 1427 addition, chemical oxygen demand increased, lipid phosphorus and bacterial count first decreased and then remained stable, and the bactericidal ratio first increased and then remained stable. Diesel addition variation has more obvious effect on ClO2 than 1427.

Long-circulating Janus nanoparticles made by electrohydrodynamic co-jetting for systemic drug delivery applications.

PubMed

Rahmani, Sahar; Villa, Carlos H; Dishman, Acacia F; Grabowski, Marika E; Pan, Daniel C; Durmaz, Hakan; Misra, Asish C; Colón-Meléndez, Laura; Solomon, Michael J; Muzykantov, Vladimir R; Lahann, Joerg

2015-01-01

Nanoparticles with controlled physical properties have been widely used for controlled release applications. In addition to shape, the anisotropic nature of the particles can be an important design criterion to ensure selective surface modification or independent release of combinations of drugs. Electrohydrodynamic (EHD) co-jetting is used for the fabrication of uniform anisotropic nanoparticles with individual compartments and initial physicochemical and biological characterization is reported. EHD co-jetting is used to create nanoparticles, which are characterized at each stage with scanning electron microscopy (SEM), structured illumination microscopy (SIM), dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). Surface immobilization techniques are used to incorporate polyethylene glycol (PEG) and I(125) radiolabels into the nanoparticles. Particles are injected in mice and the particle distribution after 1, 4 and 24 hours is assessed. Nanoparticles with an average diameter of 105.7 nm are prepared by EHD co-jetting. The particles contain functional chemical groups for further surface modification and radiolabeling. The density of PEG molecules attached to the surface of nanoparticles is determined to range between 0.02 and 6.04 ligands per square nanometer. A significant fraction of the nanoparticles (1.2% injected dose per mass of organ) circulates in the blood after 24 h. EHD co-jetting is a versatile method for the fabrication of nanoparticles for drug delivery. Circulation of the nanoparticles for 24 h is a pre-requisite for subsequent studies to explore defined targeting of the nanoparticles to a specific anatomic site.

Asynchronous warming and δ18O evolution of deep Atlantic water masses during the last deglaciation

NASA Astrophysics Data System (ADS)

Zhang, J.; Liu, Z.; Brady, E. C.; Oppo, D.; Clark, P. U.; Jahn, A.; Marcott, S. A.; Lindsay, K. T.

2017-12-01

The large-scale reorganization of deep-ocean circulation in the Atlantic involving changes in North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) played a critical role in regulating hemispheric and global climate during the last deglaciation. However, changes in the relative contributions of NADW and AABW and their properties are poorly constrained by marine records, including δ18O of benthic foraminiferal calcite (δ18Oc). Here we use an isotope-enabled ocean general circulation model with realistic geometry and forcing conditions to simulate the deglacial water mass and δ18O evolution. Model results suggest that in response to North Atlantic freshwater forcing during the early phase of the last deglaciation, NADW nearly collapses while AABW mildly weakens. Rather than reflecting changes in NADW or AABW properties due to freshwater input as suggested previously, the observed phasing difference of deep δ18Oc likely reflects early warming of the deep northern North Atlantic by 1.4°C while deep Southern Ocean temperature remains largely unchanged. We propose a thermodynamic mechanism to explain the early warming in the North Atlantic, featuring a strong mid-depth warming and enhanced downward heat flux via vertical mixing. Our results emphasize that the way ocean circulation affects heat, a dynamic tracer, is considerably different than how it affects passive tracers like δ18O, and call for caution when inferring water mass changes from δ18Oc records while assuming uniform changes in deep temperatures.

Asynchronous warming and δ18O evolution of deep Atlantic water masses during the last deglaciation

NASA Astrophysics Data System (ADS)

Zhang, Jiaxu; Liu, Zhengyu; Brady, Esther C.; Oppo, Delia W.; Clark, Peter U.; Jahn, Alexandra; Marcott, Shaun A.; Lindsay, Keith

2017-10-01

The large-scale reorganization of deep ocean circulation in the Atlantic involving changes in North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) played a critical role in regulating hemispheric and global climate during the last deglaciation. However, changes in the relative contributions of NADW and AABW and their properties are poorly constrained by marine records, including δ18O of benthic foraminiferal calcite (δ18Oc). Here, we use an isotope-enabled ocean general circulation model with realistic geometry and forcing conditions to simulate the deglacial water mass and δ18O evolution. Model results suggest that, in response to North Atlantic freshwater forcing during the early phase of the last deglaciation, NADW nearly collapses, while AABW mildly weakens. Rather than reflecting changes in NADW or AABW properties caused by freshwater input as suggested previously, the observed phasing difference of deep δ18Oc likely reflects early warming of the deep northern North Atlantic by ˜1.4 °C, while deep Southern Ocean temperature remains largely unchanged. We propose a thermodynamic mechanism to explain the early warming in the North Atlantic, featuring a strong middepth warming and enhanced downward heat flux via vertical mixing. Our results emphasize that the way that ocean circulation affects heat, a dynamic tracer, is considerably different from how it affects passive tracers, like δ18O, and call for caution when inferring water mass changes from δ18Oc records while assuming uniform changes in deep temperatures.

Upper layer circulation, hydrography, and biological response of the Andaman waters during winter monsoon based on in situ and satellite observations

NASA Astrophysics Data System (ADS)

Chandran, Salini Thaliyakkattil; Raj, Smitha Bal; Ravindran, Sajeev; Narayana, Sanjeevan Vellorkirakathil

2018-05-01

Upper layer circulation, hydrography, and biological response of Andaman waters during winter monsoon are assessed based on the observations carried out onboard FORV Sagar Sampada during January 2009 and November-December 2011. Cool and dry air carried by the moderate winds (6 m/s) from north and northeast indicates the influence of northeast monsoon (NEM) in the area during the observation time. The characteristics of physical parameters and the water mass indicate that the southeastern side is dominated by the less saline water from South China Sea intruded through the Malacca Strait, whereas the northeast is influenced by the freshwater from Ayeyarwady-Salween river system. The western side of the Andaman and Nicobar Islands exhibits similar properties of Bay of Bengal (BoB) water as evidenced in the T-S relation. Circulation pattern is uniform for the upper 88 m and is found to be more geostrophic rather than wind driven. Magnitude of the current velocity varies between 100 and 900 mm/s in November-December 2011 with strong current (900 mm/s) near Katchal and Nancowry islands and 100 and 1000 mm/s in January 2009 recording strong current (1000 mm/s) near the Little Nicobar Island. The Andaman waters are observed as less productive during the season based on the satellite-derived surface chl-a (0.1-0.4 mg/m3) and column-integrated primary productivity (PP) (100-275 mgC/m2/d).

Development of virtual patient models for permanent implant brachytherapy Monte Carlo dose calculations: interdependence of CT image artifact mitigation and tissue assignment.

PubMed

Miksys, N; Xu, C; Beaulieu, L; Thomson, R M

2015-08-07

This work investigates and compares CT image metallic artifact reduction (MAR) methods and tissue assignment schemes (TAS) for the development of virtual patient models for permanent implant brachytherapy Monte Carlo (MC) dose calculations. Four MAR techniques are investigated to mitigate seed artifacts from post-implant CT images of a homogeneous phantom and eight prostate patients: a raw sinogram approach using the original CT scanner data and three methods (simple threshold replacement (STR), 3D median filter, and virtual sinogram) requiring only the reconstructed CT image. Virtual patient models are developed using six TAS ranging from the AAPM-ESTRO-ABG TG-186 basic approach of assigning uniform density tissues (resulting in a model not dependent on MAR) to more complex models assigning prostate, calcification, and mixtures of prostate and calcification using CT-derived densities. The EGSnrc user-code BrachyDose is employed to calculate dose distributions. All four MAR methods eliminate bright seed spot artifacts, and the image-based methods provide comparable mitigation of artifacts compared with the raw sinogram approach. However, each MAR technique has limitations: STR is unable to mitigate low CT number artifacts, the median filter blurs the image which challenges the preservation of tissue heterogeneities, and both sinogram approaches introduce new streaks. Large local dose differences are generally due to differences in voxel tissue-type rather than mass density. The largest differences in target dose metrics (D90, V100, V150), over 50% lower compared to the other models, are when uncorrected CT images are used with TAS that consider calcifications. Metrics found using models which include calcifications are generally a few percent lower than prostate-only models. Generally, metrics from any MAR method and any TAS which considers calcifications agree within 6%. Overall, the studied MAR methods and TAS show promise for further retrospective MC dose calculation studies for various permanent implant brachytherapy treatments.

Soil fate of agricultural fumigants in raised-bed, plasticulture systems in the southeastern United States.

PubMed

Chellemi, Dan O; Ajwa, Husein A; Sullivan, David A; Alessandro, Rocco; Gilreath, James P; Yates, Scott R

2011-01-01

Soil concentrations and degradation rates of methyl isothio-cyanate (MITC), chloropicrin (CP), 1,3-dichloropropene (1,3-D), and dimethyl disulfide (DMDS) were determined under fumigant application scenarios representative of commercial raised bed, plastic mulched vegetable production systems. Five days after application, 1,3-D, MITC, and CP were detected at concentrations up to 3.52, 0.72, and 2.45 μg cm, respectively, in the soil atmosphere when applications were made in uniformly compacted soils with a water content >200% of field capacity and covered by a virtually impermeable or metalized film. By contrast, DMDS, MITC, and CP concentrations in the soil atmosphere were 0.81, 0.02, and 0.05 μg cm, respectively, 5 d after application in soil containing undecomposed plant residue, numerous large (>3 mm) clods, and water content below field capacity and covered by low-density polyethylene. Ranked in order of impact on the persistence of fumigants in soil were soil water content (moisture), soil tilth (the physical condition of soil as related to its fitness as a planting bed), the type of plastic film used to cover fumigated beds, and soil texture. Fumigants were readily detected 13 d after application when applied in uniformly compacted soils with water contents >200% of capacity and covered by a virtually impermeable or metalized film. By contrast, 1,3-D and MITC had dissipated 5 d after application in soils with numerous large (>3 mm) clods and water contents below field capacity that were covered by low-density polyethylene. Soil degradation of CP, DMDS, and MITC were primarily attributed to biological mechanisms, whereas degradation of 1,3-D was attributed principally to abiotic factors. This study demonstrates improved soil retention of agricultural fumigants in application scenarios representative of good agricultural practices. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

The effect of anterior proton beams in the setting of a prostate-rectum spacer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christodouleas, John P., E-mail: christojo@uphs.upenn.edu; Tang, Shikui; Susil, Robert C.

2013-10-01

Studies suggest that anterior beams with in vivo range verification would improve rectal dosimetry in proton therapy for prostate cancer. We investigated whether prostate-rectum spacers would enhance or diminish the benefits of anterior proton beams in these treatments. Twenty milliliters of hydrogel was injected between the prostate and rectum of a cadaver using a transperineal approach. Computed tomography (CT) and magnetic resonance (MR) images were used to generate 7 uniform scanning (US) and 7 single-field uniform dose pencil-beam scanning (PBS) plans with different beam arrangements. Pearson correlations were calculated between rectal, bladder, and femoral head dosimetric outcomes and beam arrangementmore » anterior scores, which characterize the degree to which dose is delivered anteriorly. The overall quality of each plan was compared using a virtual dose-escalation study. For US plans, rectal mean dose was inversely correlated with anterior score, but for PBS plans there was no association between rectal mean dose and anterior score. For both US and PBS plans, full bladder and empty bladder mean doses were correlated with anterior scores. For both US and PBS plans, femoral head mean doses were inversely correlated with anterior score. For US plans and a full bladder, 4 beam arrangements that included an anterior beam tied for the highest maximum prescription dose (MPD). For US plans and an empty bladder, the arrangement with 1 anterior and 2 anterior oblique beams achieved the highest MPD in the virtual dose-escalation study. The dose-escalation study did not differentiate beam arrangements for PBS. All arrangements in the dose-escalation study were limited by bladder constraints except for the arrangement with 2 posterior oblique beams. The benefits of anterior proton beams in the setting of prostate-rectum spacers appear to be proton modality dependent and may not extend to PBS.« less

The effect of anterior proton beams in the setting of a prostate-rectum spacer

PubMed Central

Christodouleas, John P.; Tang, Shikui; Susil, Robert C.; McNutt, Todd R.; Song, Danny Y.; Bekelman, Justin; Deville, Curtiland; Vapiwala, Neha; DeWeese, Theodore L.; Lu, Hsiao-Ming; Both, Stefan

2014-01-01

Studies suggest that anterior beams with in vivo range verification would improve rectal dosimetry in proton therapy for prostate cancer. We investigated whether prostate-rectum spacers would enhance or diminish the benefits of anterior proton beams in these treatments. Twenty milliliters of hydrogel was injected between the prostate and rectum of a cadaver using a transperineal approach. Computed tomography (CT) and magnetic resonance (MR) images were used to generate 7 uniform scanning (US) and 7 single-field uniform dose pencil-beam scanning (PBS) plans with different beam arrangements. Pearson correlations were calculated between rectal, bladder, and femoral head dosimetric outcomes and beam arrangement anterior scores, which characterize the degree to which dose is delivered anteriorly. The overall quality of each plan was compared using a virtual dose-escalation study. For US plans, rectal mean dose was inversely correlated with anterior score, but for PBS plans there was no association between rectal mean dose and anterior score. For both US and PBS plans, full bladder and empty bladder mean doses were correlated with anterior scores. For both US and PBS plans, femoral head mean doses were inversely correlated with anterior score. For US plans and a full bladder, 4 beam arrangements that included an anterior beam tied for the highest maximum prescription dose (MPD). For US plans and an empty bladder, the arrangement with 1 anterior and 2 anterior oblique beams achieved the highest MPD in the virtual dose-escalation study. The dose-escalation study did not differentiate beam arrangements for PBS. All arrangements in the dose-escalation study were limited by bladder constraints except for the arrangement with 2 posterior oblique beams. The benefits of anterior proton beams in the setting of prostate-rectum spacers appear to be proton modality dependent and may not extend to PBS. PMID:23578497

Multiblock High Order Large Eddy Simulation of Powered Fontan Hemodynamics: Towards Computational Surgery

PubMed Central

Delorme, Yann T.; Rodefeld, Mark D.; Frankel, Steven H.

2016-01-01

Children born with only one functional ventricle must typically undergo a series of three surgeries to obtain the so-called Fontan circulation in which the blood coming from the body passively flows from the Vena Cavae (VCs) to the Pulmonary Arteries (PAs) through the Total Cavopulmonary Connection (TCPC). The circulation is inherently inefficient due to the lack of a subpulmonary ventricle. Survivors face the risk of circulatory sequelae and eventual failure for the duration of their lives. Current efforts are focused on improving the outcomes of Fontan palliation, either passively by optimizing the TCPC, or actively by using mechanical support. We are working on a chronic implant that would be placed at the junction of the TCPC, and would provide the necessary pressure augmentation to re-establish a circulation that recapitulates a normal two-ventricle circulation. This implant is based on the Von Karman viscous pump and consists of a vaned impeller that rotates inside the TCPC. To evaluate the performance of such a device, and to study the flow features induced by the presence of the pump, Computational Fluid Dynamics (CFD) is used. CFD has become an important tool to understand hemodynamics owing to the possibility of simulating quickly a large number of designs and flow conditions without any harm for patients. The transitional and unsteady nature of the flow can make accurate simulations challenging. We developed and in-house high order Large Eddy Simulation (LES) solver coupled to a recent Immersed Boundary Method (IBM) to handle complex geometries. Multiblock capability is added to the solver to allow for efficient simulations of complex patient specific geometries. Blood simulations are performed in a complex patient specific TCPC geometry. In this study, simulations without mechanical assist are performed, as well as after virtual implantation of the temporary and chronic implants being developed. Instantaneous flow structures, hepatic factor distribution, and statistical data are presented for all three cases. PMID:28649147

Tidal-flow, circulation, and flushing characteristics of Kings Bay, Citrus County, Florida

USGS Publications Warehouse

Hammett, K.M.; Goodwin, C.R.; Sanders, G.L.

1996-01-01

Kings Bay is an estuary on the gulf coast of peninsular Florida with a surface area of less than one square mile. It is a unique estuarine system with no significant inflowing rivers or streams. As much as 99 percent of the freshwater entering the bay originates from multiple spring vents at the bottom of the estuary. The circulation and flushing characteristics of Kings Bay were evaluated by applying SIMSYS2D, a two-dimensional numerical model. Field data were used to calibrate and verify the model. Lagrangian particle simulations were used to determine the circulation characteristics for three hydrologic conditions: low inflow, typical inflow, and low inflow with reduced friction from aquatic vegetation. Spring discharge transported the particles from Kings Bay through Crystal River and out of the model domain. Tidal effects added an oscillatory component to the particle paths. The mean particle residence time was 59 hours for low inflow with reduced friction; therefore, particle residence time is affected more by spring discharge than by bottom friction. Circulation patterns were virtually identical for the three simulated hydroloigc conditions. Simulated particles introduced in the southern part of Kings Bay traveled along the eastern side of Buzzard Island before entering Crystal River and existing the model domain. The flushing characteristics of Kings Bay for the three hydrodynamic conditions were determined by simulating the injection of conservative dye constituents. The average concentration of dye initially injected in Kings Bay decreased asymptotically because of spring discharge, and the tide caused some oscillation in the average dye concentration. Ninety-five percent of the injected dye exited Kings Bay and Crystal River with 94 hours for low inflow, 71 hours for typical inflow, and 94 hours for low inflow with reduced bottom friction. Simulation results indicate that all of the open waters of Kings Bay are flushed by the spring discharge. Reduced bottom friction has little effect on flushing.

Bringing the Virtual Astronomical Observatory to the Education Community

NASA Astrophysics Data System (ADS)

Lawton, B.; Eisenhamer, B.; Mattson, B. J.; Raddick, M. J.

2012-08-01

The Virtual Observatory (VO) is an international effort to bring a large-scale electronic integration of astronomy data, tools, and services to the global community. The Virtual Astronomical Observatory (VAO) is the U.S. NSF- and NASA-funded VO effort that seeks to put efficient astronomical tools in the hands of U.S. astronomers, students, educators, and public outreach leaders. These tools will make use of data collected by the multitude of ground- and space-based missions over the previous decades. The Education and Public Outreach (EPO) program for the VAO will be led by the Space Telescope Science Institute in collaboration with the High Energy Astrophysics Science Archive Research Center (HEASARC) EPO program and Johns Hopkins University. VAO EPO efforts seek to bring technology, real-world astronomical data, and the story of the development and infrastructure of the VAO to the general public and education community. Our EPO efforts will be structured to provide uniform access to VAO information, enabling educational and research opportunities across multiple wavelengths and time-series data sets. The VAO team recognizes that the VO has already built many tools for EPO purposes, such as Microsoft's World Wide Telescope, SDSS Sky Server, Aladin, and a multitude of citizen-science tools available from Zooniverse. However, it is not enough to simply provide tools. Tools must meet the needs of the education community and address national education standards in order to be broadly utilized. To determine which tools the VAO will incorporate into the EPO program, needs assessments will be conducted with educators across the U.S.

Atmospheric volatilization and distribution of (Z)- and (E)-1,3-dichloropropene in field beds with and without plastic covers.

PubMed

Thomas, John E; Allen, L Hartwell; McCormack, Leslie A; Vu, Joseph C; Dickson, Donald W; Ou, Li-Tse

2004-01-01

The fumigant 1,3-dichloropropene (1,3-D) is considered to be a potential replacement for methyl bromide when methyl bromide is phased out in 2005. This study on surface emissions and subsurface diffusion of 1,3-D in a Florida sandy soil was conducted in field beds with or without plastic covers. After injection of the commercial fumigant Telone II by conventional chisels to field beds at 30cm depth which were covered with polyethylene film (PE), virtually impermeable film, or no cover (bare), (Z)- and (E)-1,3-D rapidly diffused upward. Twenty hours after injection, majority of (Z)- and (E)-1,3-D had moved upward from 30 cm depth to the layer of 5-20 cm depth. Downward movement of the two isomers in the beds with or without a plastic cover was not significant. (Z)-1,3-D diffused more rapidly than (E)-1,3-D. Virtually impermeable films (VIF) had a good capacity to retain (Z)- and (E)-1,3-D in soil pore air space. Vapor concentrations of the two isomers in the shallow subsurface of the field bed covered with VIF were greater than that in the two beds covered with polyethylene film (PE) or no cover (bare). In addition, VIF cover provided more uniform distribution of (Z)- and (E)-1,3-D in shallow subsurface than PE cover or no cover. Virtually impermeable film also had a better capability to retard surface emissions of the two isomers from soil in field beds than PE cover or no cover.

Ex vivo blood vessel bioreactor for analysis of the biodegradation of magnesium stent models with and without vessel wall integration

PubMed Central

Wang, Juan; Liu, Lumei; Wu, Yifan; Maitz, Manfred F.; Wang, Zhihong; Koo, Youngmi; Zhao, Ansha; Sankar, Jagannathan; Kong, Deling; Huang, Nan; Yun, Yeoheung

2017-01-01

Current in vitro models fail in predicting the degradation rate and mode of magnesium (Mg) stents in vivo. To overcome this, the microenvironment of the stent is simulated here in an ex vivo bioreactor with porcine aorta and circulating medium, and compared with standard static in vitro immersion and with in vivo rat aorta models. In ex vivo and in vivo conditions, pure Mg wires were exposed to the aortic lumen and inserted into the aortic wall to mimic early- and long-term implantation, respectively. Results showed that: 1) Degradation rates of Mg were similar for all the fluid diffusion conditions (in vitro static, aortic wall ex vivo and in vivo); however, Mg degradation under flow condition (i.e. in the lumen) in vivo was slower than ex vivo; 2) The corrosion mode in the samples can be mainly described as localized (in vitro), mixed localized and uniform (ex vivo), and uniform (in vivo); 3) Abundant degradation products (MgO/Mg(OH)2 and Ca/P) with gas bubbles accumulated around the localized degradation regions ex vivo, but a uniform and thin degradation product layer was found in vivo. It is concluded that the ex vivo vascular bioreactor provides an improved test setting for magnesium degradation between static immersion and animal experiments and highlights its promising role in bridging degradation behavior and biological response for vascular stent research. PMID:28013101

Uniformity of environmental conditions and plant growth in a hydroponic culture system for use in a growth room with aerial CO2 control

NASA Technical Reports Server (NTRS)

Vessey, J. K.; York, E. K.; Henry, L. T.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

1988-01-01

A portable system of hydroponic culture was developed that maintained temperature, pH, and nutrient concentrations of circulating nutrient solutions. The hydroponic system is used within a controlled-environment room (CER) for control of aerial environment. The CER was equipped with an auto-calibrating system for atmospheric CO2 control. The control systems for the hydroponic chambers were able to maintain acidity within +/- 0.2 pH units and the temperature with +/- 0.5 degree C. Mixing time for the 200-liter volume of solution within a hydroponic chamber was less than 12 min. The CO2 control system was able to maintain aerial concentrations within +/- 10 ppm CO2 during the light period. The only gradient found to occur within the hydroponic chambers or CER was a slight gradient in aerial temperature along the length of hydroponic chambers. Growth of soybeans [Glycine max (L.) Merr.] was characterized during a 3-week period of vegetative development by leaf number and area, plant dry weight, total N content of plants, and N depletion from the nutrient solution. The growth characteristics among populations for three hydroponic chambers within the CER were not significantly different, and the percent standard errors of means of the measurements within populations from each chamber were nearly all less than 10%. Thus, the uniformity of plant growth reflected the uniformity of environmental conditions.

Uniform Recovery Bounds for Structured Random Matrices in Corrupted Compressed Sensing

NASA Astrophysics Data System (ADS)

Zhang, Peng; Gan, Lu; Ling, Cong; Sun, Sumei

2018-04-01

We study the problem of recovering an $s$-sparse signal $\\mathbf{x}^{\\star}\\in\\mathbb{C}^n$ from corrupted measurements $\\mathbf{y} = \\mathbf{A}\\mathbf{x}^{\\star}+\\mathbf{z}^{\\star}+\\mathbf{w}$, where $\\mathbf{z}^{\\star}\\in\\mathbb{C}^m$ is a $k$-sparse corruption vector whose nonzero entries may be arbitrarily large and $\\mathbf{w}\\in\\mathbb{C}^m$ is a dense noise with bounded energy. The aim is to exactly and stably recover the sparse signal with tractable optimization programs. In this paper, we prove the uniform recovery guarantee of this problem for two classes of structured sensing matrices. The first class can be expressed as the product of a unit-norm tight frame (UTF), a random diagonal matrix and a bounded columnwise orthonormal matrix (e.g., partial random circulant matrix). When the UTF is bounded (i.e. $\\mu(\\mathbf{U})\\sim1/\\sqrt{m}$), we prove that with high probability, one can recover an $s$-sparse signal exactly and stably by $l_1$ minimization programs even if the measurements are corrupted by a sparse vector, provided $m = \\mathcal{O}(s \\log^2 s \\log^2 n)$ and the sparsity level $k$ of the corruption is a constant fraction of the total number of measurements. The second class considers randomly sub-sampled orthogonal matrix (e.g., random Fourier matrix). We prove the uniform recovery guarantee provided that the corruption is sparse on certain sparsifying domain. Numerous simulation results are also presented to verify and complement the theoretical results.

Pulse sequences for uniform perfluorocarbon droplet vaporization and ultrasound imaging.

PubMed

Puett, C; Sheeran, P S; Rojas, J D; Dayton, P A

2014-09-01

Phase-change contrast agents (PCCAs) consist of liquid perfluorocarbon droplets that can be vaporized into gas-filled microbubbles by pulsed ultrasound waves at diagnostic pressures and frequencies. These activatable contrast agents provide benefits of longer circulating times and smaller sizes relative to conventional microbubble contrast agents. However, optimizing ultrasound-induced activation of these agents requires coordinated pulse sequences not found on current clinical systems, in order to both initiate droplet vaporization and image the resulting microbubble population. Specifically, the activation process must provide a spatially uniform distribution of microbubbles and needs to occur quickly enough to image the vaporized agents before they migrate out of the imaging field of view. The development and evaluation of protocols for PCCA-enhanced ultrasound imaging using a commercial array transducer are described. The developed pulse sequences consist of three states: (1) initial imaging at sub-activation pressures, (2) activating droplets within a selected region of interest, and (3) imaging the resulting microbubbles. Bubble clouds produced by the vaporization of decafluorobutane and octafluoropropane droplets were characterized as a function of focused pulse parameters and acoustic field location. Pulse sequences were designed to manipulate the geometries of discrete microbubble clouds using electronic steering, and cloud spacing was tailored to build a uniform vaporization field. The complete pulse sequence was demonstrated in the water bath and then in vivo in a rodent kidney. The resulting contrast provided a significant increase (>15 dB) in signal intensity. Copyright © 2014 Elsevier B.V. All rights reserved.

Coherent Light induced in Optical Fiber by a Charged Particle

NASA Astrophysics Data System (ADS)

Artru, Xavier; Ray, Cédric

2016-07-01

Coherent light production in an optical fiber by a charged particle (named PIGL, for particle-induced guided, light) is reviewed. From the microscopic point of view, light is emitted by transient electric dipoles induced in the fiber medium by the Coulomb field of the particle. The phenomenon can also considered as the capture of virtual photons of the particle field by the fiber. Two types of captures are distinguished. Type-I takes place in a uniform part of the fiber; then the photon keeps its longitudinal momentum pz . Type-II takes place near an end or in a non-uniform part of the fiber; then pz is not conserved. Type-I PIGL is not affected by background lights external to the fiber. At grazing incidence it becomes nearly monochromatic. Its circular polarization depends on the angular momentum of the particle about the fiber and on the relative velocity between the particle and the guided wave. A general formula for the yield of Type-II radiation, based on the reciprocity theorem, is proposed. This radiation can be assisted by metallic objects stuck to the fiber, via plasmon excitation. A periodic structure leads to a guided Smith-Purcell radiation. Applications of PIGL in beam diagnostics are considered.

Between giant oscillations and uniform distribution of droplets: The role of varying lumen of channels in microfluidic networks.

PubMed

Cybulski, Olgierd; Jakiela, Slawomir; Garstecki, Piotr

2015-12-01

The simplest microfluidic network (a loop) comprises two parallel channels with a common inlet and a common outlet. Recent studies that assumed a constant cross section of the channels along their length have shown that the sequence of droplets entering the left (L) or right (R) arm of the loop can present either a uniform distribution of choices (e.g., RLRLRL...) or long sequences of repeated choices (RRR...LLL), with all the intermediate permutations being dynamically equivalent and virtually equally probable to be observed. We use experiments and computer simulations to show that even small variation of the cross section along channels completely shifts the dynamics either into the strong preference for highly grouped patterns (RRR...LLL) that generate system-size oscillations in flow or just the opposite-to patterns that distribute the droplets homogeneously between the arms of the loop. We also show the importance of noise in the process of self-organization of the spatiotemporal patterns of droplets. Our results provide guidelines for rational design of systems that reproducibly produce either grouped or homogeneous sequences of droplets flowing in microfluidic networks.

Stresses and deformations in cross-ply composite tubes subjected to a uniform temperature change

NASA Technical Reports Server (NTRS)

Hyer, M. W.; Cooper, D. E.; Cohen, D.

1986-01-01

This study investigates the effects of a uniform temperature change on the stresses and deformations of composite tubes and determines the accuracy of an approximate solution based on the principle of complementary virtual work. Interest centers on tube response away from the ends and so a planar elasticity approach is used. For the approximate solution a piecewise linear variation of stresses with the radial coordinate is assumed. The results from the approximate solution are compared with the elasticity solution. The stress predictions agree well, particularly peak interlaminar stresses. Surprisingly, the axial deformations also agree well, despite the fact that the deformations predicted by the approximate solution do not satisfy the interface displacement continuity conditions required by the elasticity solution. The study shows that the axial thermal expansion coefficient of tubes with a specific number of axial and circumferential layers depends on the stacking sequence. This is in contrast to classical lamination theory, which predicts that the expansion will be independent of the stacking arrangement. As expected, the sign and magnitude of the peak interlaminar stresses depend on stacking sequence. For tubes with a specific number of axial and circumferential layers, thermally induced interlaminar stresses can be controlled by altering stacking arrangement.

Hadley cell dynamics of a cold and virtually dry Snowball Earth atmosphere

NASA Astrophysics Data System (ADS)

Voigt, Aiko; Held, Isaac; Marotzke, Jochem

2010-05-01

We use the full-physics atmospheric general circulation model ECHAM5 to investigate a cold and virtually dry Snowball Earth atmosphere that results from specifying sea ice as the surface boundary condition everywhere, corresponding to a frozen aquaplanet, while keeping total solar irradiance at its present-day value of 1365 Wm-2. The aim of this study is the investigation of the zonal-mean circulation of a Snowball Earth atmosphere, which, due to missing moisture, might constitute an ideal though yet unexplored testbed for theories of atmospheric dynamics. To ease comparison with theories, incoming solar insolation follows permanent equinox conditions with disabled diurnal cycle. The meridional circulation consists of a thermally direct cell extending from the equator to 45 N/S with ascent in the equatorial region, and a weak thermally indirect cell with descent between 45 and 65 N/S and ascent in the polar region. The former cell corresponds to the present-day Earth's Hadley cell, while the latter can be viewed as an eddy-driven Ferrell cell; the present-day Earth's direct polar cell is missing. The Hadley cell itself is subdivided into a vigorous cell confined to the troposphere and a weak deep cell reaching well into the stratosphere. The dynamics of the vigorous Snowball Earth Hadley cell differ substantially from the dynamics of the present-day Hadley cell. The zonal momentum balance shows that in the poleward branch of the vigorous Hadley cell, mean flow meridional advection of absolute vorticity is not only balanced by eddy momentum flux convergence but also by vertical diffusion. Inside the poleward branch, eddies are more important in the upper part and vertical diffusion is more important in the lower part. Vertical diffusion also contributes to the meridional momentum balance as it decelerates the vigorous Hadley cell by downgradient momentum mixing between its poleward and equatorward branch. Zonal winds, therefore, are not in thermal wind balance in the vigorous Hadley cell. Suppressing vertical momentum diffusion above 870 hPa results in a doubling of the vigorous Hadley cell strength. Simulations where we only suppress either vertical diffusion of zonal or meridional momentum show that this doubling can be understood from the decelerating effect of vertical diffusion in the meridional momentum balance. Comparing our simulations with theories, we conclude that neither the axisymmetric Hadley cell model of Held & Hou (1980) nor the eddy-permitting model of T. Schneider et al. (2005, 2006, 2008) are applicable to a Snowball Earth atmosphere since both assume an inviscid upper Hadley cell branch.

Effects of coolant parameters on steady state temperature distribution in phospheric-acid fuel cell electrode

NASA Technical Reports Server (NTRS)

Alkasab, K. A.; Abdul-Aziz, A.

1991-01-01

The influence of thermophysical properties and flow rate on the steady-state temperature distribution in a phosphoric-acid fuel cell electrode plate was experimentally investigated. An experimental setup that simulates the operating conditions prevailing in a phosphoric-acid fuel cell stack was used. The fuel cell cooling system utilized three types of coolants to remove excess heat generated in the cell electrode and to maintain a reasonably uniform temperature distribution in the electrode plate. The coolants used were water, engine oil, and air. These coolants were circulated at Reynolds number ranging from 1165 to 6165 for water; 3070 to 6864 for air; and 15 to 79 for oil. Experimental results are presented.

MO-FG-CAMPUS-IeP1-04: Kerma Area Product Calculation for Non-Uniform X-Ray Fields Using a Skin Dose Tracking System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vijayan, S; Xiong, Z; Rudin, S

Purpose: The functionality of the Dose-Tracking System (DTS) has been expanded to include the calculation of the Kerma-Area Product (KAP) for non-uniform x-ray fields such as result from the use of compensation filters during fluoroscopic procedures Methods: The DTS calculates skin dose during fluoroscopic interventions and provides a color-coded dose map on a patient-graphic model. The KAP is the integral of air kerma over the x-ray field and is usually measured with a transmission-ionization chamber that intercepts the entire x-ray beam. The DTS has been modified to determine KAP when there are beam non-uniformities that can be modeled. For example,more » the DTS includes models of the three compensation filters with tapered edges located in the collimator assembly of the Toshiba Infinix fluoroscopic C-Arm and can track their movement. To determine the air kerma after the filters, DTS includes transmission factors for the compensation filters as a function of kVp and beam filtration. A virtual KAP dosimeter is simulated in the DTS by an array of graphic vertices; the air kerma at each vertex is corrected by the field non-uniformity, which in this case is the attenuation factor for those rays which pass through the filter. The products of individual vertex air-kerma values for all vertices within the beam times the effective-area-per-vertex are summed for each x-ray pulse to yield the KAP per pulse and the cumulative KAP for the procedure is then calculated. Results: The KAP values estimated by DTS with the compensation filter inserted into the x-ray field agree within ± 6% with the values displayed on the fluoroscopy unit monitor, which are measured with a transmission chamber. Conclusion: The DTS can account for field non-uniformities such as result from the use of compensation filters in calculating KAP and can obviate the need for a KAP transmission ionization chamber. Partial support from NIH Grant R01-EB002873 and Toshiba Medical Systems Corp.« less

Re-Evaluation of Event Correlations in Virtual California Using Statistical Analysis

NASA Astrophysics Data System (ADS)

Glasscoe, M. T.; Heflin, M. B.; Granat, R. A.; Yikilmaz, M. B.; Heien, E.; Rundle, J.; Donnellan, A.

2010-12-01

Fusing the results of simulation tools with statistical analysis methods has contributed to our better understanding of the earthquake process. In a previous study, we used a statistical method to investigate emergent phenomena in data produced by the Virtual California earthquake simulator. The analysis indicated that there were some interesting fault interactions and possible triggering and quiescence relationships between events. We have converted the original code from Matlab to python/C++ and are now evaluating data from the most recent version of Virtual California in order to analyze and compare any new behavior exhibited by the model. The Virtual California earthquake simulator can be used to study fault and stress interaction scenarios for realistic California earthquakes. The simulation generates a synthetic earthquake catalog of events with a minimum size of ~M 5.8 that can be evaluated using statistical analysis methods. Virtual California utilizes realistic fault geometries and a simple Amontons - Coulomb stick and slip friction law in order to drive the earthquake process by means of a back-slip model where loading of each segment occurs due to the accumulation of a slip deficit at the prescribed slip rate of the segment. Like any complex system, Virtual California may generate emergent phenomena unexpected even by its designers. In order to investigate this, we have developed a statistical method that analyzes the interaction between Virtual California fault elements and thereby determine whether events on any given fault elements show correlated behavior. Our method examines events on one fault element and then determines whether there is an associated event within a specified time window on a second fault element. Note that an event in our analysis is defined as any time an element slips, rather than any particular “earthquake” along the entire fault length. Results are then tabulated and then differenced with an expected correlation, calculated by assuming a uniform distribution of events in time. We generate a correlation score matrix, which indicates how weakly or strongly correlated each fault element is to every other in the course of the VC simulation. We calculate correlation scores by summing the difference between the actual and expected correlations over all time window lengths and normalizing by the time window size. The correlation score matrix can focus attention on the most interesting areas for more in-depth analysis of event correlation vs. time. The previous study included 59 faults (639 elements) in the model, which included all the faults save the creeping section of the San Andreas. The analysis spanned 40,000 yrs of Virtual California-generated earthquake data. The newly revised VC model includes 70 faults, 8720 fault elements, and spans 110,000 years. Due to computational considerations, we will evaluate the elements comprising the southern California region, which our previous study indicated showed interesting fault interaction and event triggering/quiescence relationships.

Simulation of Venus polar vortices with the non-hydrostatic general circulation model

NASA Astrophysics Data System (ADS)

Rodin, Alexander V.; Mingalev, Oleg; Orlov, Konstantin

2012-07-01

The dynamics of Venus atmosphere in the polar regions presents a challenge for general circulation models. Numerous images and hyperspectral data from Venus Express mission shows that above 60 degrees latitude atmospheric motion is substantially different from that of the tropical and extratropical atmosphere. In particular, extended polar hoods composed presumably of fine haze particles, as well as polar vortices revealing mesoscale wave perturbations with variable zonal wavenumbers, imply the significance of vertical motion in these circulation elements. On these scales, however, hydrostatic balance commonly used in the general circulation models is no longer valid, and vertical forces have to be taken into account to obtain correct wind field. We present the first non-hydrostatic general circulation model of the Venus atmosphere based on the full set of gas dynamics equations. The model uses uniform grid with the resolution of 1.2 degrees in horizontal and 200 m in the vertical direction. Thermal forcing is simulated by means of relaxation approximation with specified thermal profile and time scale. The model takes advantage of hybrid calculations on graphical processors using CUDA technology in order to increase performance. Simulations show that vorticity is concentrated at high latitudes within planetary scale, off-axis vortices, precessing with a period of 30 to 40 days. The scale and position of these vortices coincides with polar hoods observed in the UV images. The regions characterized with high vorticity are surrounded by series of small vortices which may be caused by shear instability of the zonal flow. Vertical velocity component implies that in the central part of high vorticity areas atmospheric flow is downwelling and perturbed by mesoscale waves with zonal wavenumbers 1-4, resembling observed wave structures in the polar vortices. Simulations also show the existence of areas with strong vertical flow, concentrated in spiral branches extending from low latitude to the circumpolar vortex. Qualitatively this pattern suggest that the dynamics of the polar Venus atmosphere resembles that of terrestrial hurricanes, but is characterized with preferentially poleward and downwelling motions.

Impact of air-sea drag coefficient for latent heat flux on large scale climate in coupled and atmosphere stand-alone simulations

NASA Astrophysics Data System (ADS)

Torres, Olivier; Braconnot, Pascale; Marti, Olivier; Gential, Luc

2018-05-01

The turbulent fluxes across the ocean/atmosphere interface represent one of the principal driving forces of the global atmospheric and oceanic circulation. Despite decades of effort and improvements, representation of these fluxes still presents a challenge due to the small-scale acting turbulent processes compared to the resolved scales of the models. Beyond this subgrid parameterization issue, a comprehensive understanding of the impact of air-sea interactions on the climate system is still lacking. In this paper we investigates the large-scale impacts of the transfer coefficient used to compute turbulent heat fluxes with the IPSL-CM4 climate model in which the surface bulk formula is modified. Analyzing both atmosphere and coupled ocean-atmosphere general circulation model (AGCM, OAGCM) simulations allows us to study the direct effect and the mechanisms of adjustment to this modification. We focus on the representation of latent heat flux in the tropics. We show that the heat transfer coefficients are highly similar for a given parameterization between AGCM and OAGCM simulations. Although the same areas are impacted in both kind of simulations, the differences in surface heat fluxes are substantial. A regional modification of heat transfer coefficient has more impact than uniform modification in AGCM simulations while in OAGCM simulations, the opposite is observed. By studying the global energetics and the atmospheric circulation response to the modification, we highlight the role of the ocean in dampening a large part of the disturbance. Modification of the heat exchange coefficient modifies the way the coupled system works due to the link between atmospheric circulation and SST, and the different feedbacks between ocean and atmosphere. The adjustment that takes place implies a balance of net incoming solar radiation that is the same in all simulations. As there is no change in model physics other than drag coefficient, we obtain similar latent heat flux between coupled simulations with different atmospheric circulations. Finally, we analyze the impact of model tuning and show that it can offset part of the feedbacks.

[A focused sound field measurement system by LabVIEW].

PubMed

Jiang, Zhan; Bai, Jingfeng; Yu, Ying

2014-05-01

In this paper, according to the requirement of the focused sound field measurement, a focused sound field measurement system was established based on the LabVIEW virtual instrument platform. The system can automatically search the focus position of the sound field, and adjust the scanning path according to the size of the focal region. Three-dimensional sound field scanning time reduced from 888 hours in uniform step to 9.25 hours in variable step. The efficiency of the focused sound field measurement was improved. There is a certain deviation between measurement results and theoretical calculation results. Focal plane--6 dB width difference rate was 3.691%, the beam axis--6 dB length differences rate was 12.937%.

Simulation of the development and interaction of instabilities in a relativistic electron beam under variation of the beam wall thickness

DOE Office of Scientific and Technical Information (OSTI.GOV)

Badarin, A. A.; Kurkin, S. A.; Koronovskii, A. A.

The development and interaction of Bursian and diocotron instabilities in an annular relativistic electron beam propagating in a cylindrical drift chamber are investigated analytically and numerically as functions of the beam wall thickness and the magnitude of the external uniform magnetic field. It is found that the interaction of instabilities results in the formation of a virtual cathode with a complicated rotating helical structure and several reflection regions (electron bunches) in the azimuthal direction. It is shown that the number of electron bunches in the azimuthal direction increases with decreasing beam wall thickness and depends in a complicated manner onmore » the magnitude of the external magnetic field.« less

Method for control of subsurface coal gasification

DOEpatents

Komar, Charles A.

1976-12-14

The burn front in an in situ underground coal gasification operation is controlled by utilizing at least two parallel groups of vertical bore holes disposed in the coalbed at spaced-apart locations in planes orthogonal to the plane of maximum permeability in the coalbed. The combustion of the coal is initiated in the coalbed adjacent to one group of the bore holes to establish a combustion zone extending across the group while the pressure of the combustion supporting gas mixture and/or the combustion products is regulated at each well head by valving to control the burn rate and maintain a uniform propagation of the burn front between the spaced-apart hole groups to gasify virtually all the coal lying therebetween.

Blueprint for antimicrobial hit discovery targeting metabolic networks.

PubMed

Shen, Y; Liu, J; Estiu, G; Isin, B; Ahn, Y-Y; Lee, D-S; Barabási, A-L; Kapatral, V; Wiest, O; Oltvai, Z N

2010-01-19

Advances in genome analysis, network biology, and computational chemistry have the potential to revolutionize drug discovery by combining system-level identification of drug targets with the atomistic modeling of small molecules capable of modulating their activity. To demonstrate the effectiveness of such a discovery pipeline, we deduced common antibiotic targets in Escherichia coli and Staphylococcus aureus by identifying shared tissue-specific or uniformly essential metabolic reactions in their metabolic networks. We then predicted through virtual screening dozens of potential inhibitors for several enzymes of these reactions and showed experimentally that a subset of these inhibited both enzyme activities in vitro and bacterial cell viability. This blueprint is applicable for any sequenced organism with high-quality metabolic reconstruction and suggests a general strategy for strain-specific antiinfective therapy.

On the Azimuthal Variation of Core Plasma in the Equatorial Magnetosphere

NASA Technical Reports Server (NTRS)

Gallagher, D. L.; Craven, P. D.; Comfort, R. H.; Moore, T. E.

1995-01-01

Previous results of plasmapause position surveys have been synthesized into a description of the underlying global distribution of plasmasphere-like or core plasma densities unique to a steady state magnetosphere. Under these steady conditions, the boundary between high- and low-density regions is taken to represent the boundary between diurnal near-corotation and large-scale circulation streamlines that traverse the entire magnetosphere. Results indicate a boundary that has a pronounced bulge in the dusk sector that is rotated westward and markedly reduced in size at increased levels of geomagnetic activity (and presumably magnetospheric convection). The derived profile is empirical confirmation of an underlying 'tear drop' distribution of core plasma, which is valid only for prolonged steady conditions and is somewhat different from that associated with the simple superposition of sunward flow and corotation, both in its detailed shape and in its varying orientation. Variation away from the tear drop profile suggests that magnetospheric circulation departs from a uniform flow field, having a radial dependence with respect to the Earth that is qualitatively consistent with electrostatic shielding of the convection electric field and which is rotated westward at increased levels of geophysical activity.

Tradeoff between mixing and transport for electroosmotic flow in heterogeneous microchannels with nonuniform surface potentials.

PubMed

Tian, Fuzhi; Li, Baoming; Kwok, Daniel Y

2005-02-01

Electroosmotic flow (EOF) is a phenomenon associated with the movement of an aqueous solution induced by the application of an electric field in microchannels. The characteristics of EOF depend on the nature of the surface potential, i.e., whether it is uniform or nonuniform. In this paper, a lattice Boltzmann model (LBM) combined with the Poisson-Boltzmann equation is used to simulate flow field in a rectangular microchannel with nonuniform (step change) surface potentials. The simulation results indicate that local circulations can occur near a heterogeneous region with nonuniform surface potentials, in agreement with those by other authors. Largest circulations, which imply a highest mixing efficiency due to convection and short-range diffusion, were found when the average surface potential is zero, regardless of whether the distribution of the heterogeneous patches is symmetric or asymmetric. In this work, we have illustrated that there is a trade-off between the mixing and liquid transport in EOF microfluidics. One should not simply focus on mixing and neglect liquid transport, as performed in the literature. Excellent mixing could lead to a poor transport of electroosmotic flow in microchannels.

Apparatus and method for continuous electroplating. [Patent application

DOEpatents

Conlon, T.P. Jr.; Holmes, S.D.

1981-11-19

An apparatus and method are disclosed for performing a continuous electroplating process upon an elongate conductive stock article. A closed housing assembly retaining an electroplating solution and having a conductive housing body and flexible, nonconductive end walls is connected to the positive pole of a source of electromotive force. The end walls have an aperture for receiving the conducting stock article in sliding and sealing contact. The stock article is connected to the negative pole of the source of electromotive force. The conductive housing body and the section of the conductive stock article within the housing body are coextensive, coaxial and spaced a uniform distance apart. The housing body has an inlet at the bottom and an outlet at the top allowing the housing assembly to fill completely with plating solution. The inlet has a reduced nozzle to create turbulence and spiral circulating motion of the plating solution moved by a pump connected by nonconductive conduits. The solution is circulated through an open reservoir. A coolant may be conveyed through the interior in a hollow stock article to cool the surface being electroplated. Different sizes of coaxial metal insert sleeves may be telescopically received in the housing body.

The influence of a yacht's heeling stability on optimum sail design

NASA Astrophysics Data System (ADS)

Sneyd, A. D.; Sugimoto, T.

1997-01-01

This paper presents fundamental results concerning the optimum design of yacht sails and masts. The aerodynamics of a high aspect ratio sail in uniform flow is analysed using lifting line theory to maximise thrust for a given sail area. The novel feature of this work is that thrust is optimised subject to the constraint that the aerodynamic heeling moment generated by the sail is balanced by the righting moment due to hull buoyancy (and the weight of the keel). Initially, the heel angle is therefore unknown, and determined as part of the solution process. Under the assumption of small heel angle, the problem reduces to minimising a quadratic form in the Fourier coefficients for the circulation distribution along the mast, and a simple analytic solution can be derived. It is found that if the mast is too high, the upper section is unused, and as a consequence there is a theoretically ideal mast height for a yacht of given heeling stability. Under the constraints of given sail area and heeling equilibrium it is found that no advantage is to be gained by allowing reverse circulation near the top of the mast. Various implications for yacht performance are discussed.

An interactive tool for outdoor computer controlled cultivation of microalgae in a tubular photobioreactor system.

PubMed

Dormido, Raquel; Sánchez, José; Duro, Natividad; Dormido-Canto, Sebastián; Guinaldo, María; Dormido, Sebastián

2014-03-06

This paper describes an interactive virtual laboratory for experimenting with an outdoor tubular photobioreactor (henceforth PBR for short). This virtual laboratory it makes possible to: (a) accurately reproduce the structure of a real plant (the PBR designed and built by the Department of Chemical Engineering of the University of Almería, Spain); (b) simulate a generic tubular PBR by changing the PBR geometry; (c) simulate the effects of changing different operating parameters such as the conditions of the culture (pH, biomass concentration, dissolved O2, inyected CO2, etc.); (d) simulate the PBR in its environmental context; it is possible to change the geographic location of the system or the solar irradiation profile; (e) apply different control strategies to adjust different variables such as the CO2 injection, culture circulation rate or culture temperature in order to maximize the biomass production; (f) simulate the harvesting. In this way, users can learn in an intuitive way how productivity is affected by any change in the design. It facilitates the learning of how to manipulate essential variables for microalgae growth to design an optimal PBR. The simulator has been developed with Easy Java Simulations, a freeware open-source tool developed in Java, specifically designed for the creation of interactive dynamic simulations.

An Interactive Tool for Outdoor Computer Controlled Cultivation of Microalgae in a Tubular Photobioreactor System

PubMed Central

Dormido, Raquel; Sánchez, José; Duro, Natividad; Dormido-Canto, Sebastián; Guinaldo, María; Dormido, Sebastián

2014-01-01

This paper describes an interactive virtual laboratory for experimenting with an outdoor tubular photobioreactor (henceforth PBR for short). This virtual laboratory it makes possible to: (a) accurately reproduce the structure of a real plant (the PBR designed and built by the Department of Chemical Engineering of the University of Almería, Spain); (b) simulate a generic tubular PBR by changing the PBR geometry; (c) simulate the effects of changing different operating parameters such as the conditions of the culture (pH, biomass concentration, dissolved O2, inyected CO2, etc.); (d) simulate the PBR in its environmental context; it is possible to change the geographic location of the system or the solar irradiation profile; (e) apply different control strategies to adjust different variables such as the CO2 injection, culture circulation rate or culture temperature in order to maximize the biomass production; (f) simulate the harvesting. In this way, users can learn in an intuitive way how productivity is affected by any change in the design. It facilitates the learning of how to manipulate essential variables for microalgae growth to design an optimal PBR. The simulator has been developed with Easy Java Simulations, a freeware open-source tool developed in Java, specifically designed for the creation of interactive dynamic simulations. PMID:24662450

Ultrasound image guidance of cardiac interventions

NASA Astrophysics Data System (ADS)

Peters, Terry M.; Pace, Danielle F.; Lang, Pencilla; Guiraudon, Gérard M.; Jones, Douglas L.; Linte, Cristian A.

2011-03-01

Surgical procedures often have the unfortunate side-effect of causing the patient significant trauma while accessing the target site. Indeed, in some cases the trauma inflicted on the patient during access to the target greatly exceeds that caused by performing the therapy. Heart disease has traditionally been treated surgically using open chest techniques with the patient being placed "on pump" - i.e. their circulation being maintained by a cardio-pulmonary bypass or "heart-lung" machine. Recently, techniques have been developed for performing minimally invasive interventions on the heart, obviating the formerly invasive procedures. These new approaches rely on pre-operative images, combined with real-time images acquired during the procedure. Our approach is to register intra-operative images to the patient, and use a navigation system that combines intra-operative ultrasound with virtual models of instrumentation that has been introduced into the chamber through the heart wall. This paper illustrates the problems associated with traditional ultrasound guidance, and reviews the state of the art in real-time 3D cardiac ultrasound technology. In addition, it discusses the implementation of an image-guided intervention platform that integrates real-time ultrasound with a virtual reality environment, bringing together the pre-operative anatomy derived from MRI or CT, representations of tracked instrumentation inside the heart chamber, and the intra-operatively acquired ultrasound images.

A numerical investigation of surface-induced mesocyclogenesis near the Gulf Stream

NASA Astrophysics Data System (ADS)

Cione, Joseph J.; Raman, Sethu

1995-10-01

A series of numerical experiments designed to simulate the initial development stages of low-level coastal mesocyclogenesis near the Gulf Stream was recently conducted. Under initially quiescent conditions, surface cyclogenesis in the control simulation occurs along a Gulf Stream meander in a region where the gradients in sea surface temperature (SST) are maximized. A low-level mesovortex on the order of 140km forms approximately 12 h into the simulation and continues to intensify through 42h. During the 24 48 h time period, a mesoscale frontal feature develops in direct response to strong diabatic forcing associated with sustained surface latent and sensible heating near the Gulf Stream frontal zone south of the main circulation center. Due to the non-linear advection of the frontal feature during this time period, the previously quasi-stationary circulation center drifts eastward (and away) from the thermal forcing associated with the large SST gradients found to the west. This eastward frontal propagation acts to decrease the magnitude of the low level horizontal air temperature gradient near the center of circulation throughout the 24 42 h development period. During the 42 48-h period, the relatively quick moving frontal feature acts to severely shear the nearly stationary center of circulation in the east west direction. As a result, the mesoscale system begins to fill during the final 6 h of integration. In addition to the control simulation, additional sensitivity experiments were conducted. These experiments were specifically designed to: (1) investigate how the magnitude of the Gulf Stream SST gradients affect the timing and degree of cyclonic development; (2) address the impact surface moisture fluxes and moist convection each have on the simulated low level mesocyclogenesis; (3) isolate the role surface sensible heating plays in the overall development of the simulated mesocyclone. Results from the SST gradient experiment indicate that a moderate enhancement of the SST distribution significantly affects the timing of the initial cyclogenesis and the maximum intensity of the simulated frontal circulation. For the "no turbulent heat flux" experiment, it appears that the elimination of surface sensible heating does not radically alter the overall structure of the simulated mesocyclone. However, the rate of development during the early stage of cyclogenesis, the absolute peak intensity of the system as well as the vertical depth of the simulated mesoscale frontal feature were all noticeably reduced when compared with the control simulation. The initial development of a closed low level circulation was delayed by nearly 18 h in the absence surface latent heat fluxes. Once formed, the system intensified throughout the 48-h period of integration, but unlike the control experiment, a mesoscale frontal feature south of the main circulation center was not simulated. Results from the "no surface moisture flux/no moist convection" simulation illustrate that moist convective processes play a dominant role in the overall development of the mesoscale cyclone. For this particular case, a weak and extremely shallow circulation was simulated after 24h. This circulation quickly eroded however, and was virtually non-existent for integration times greater than 39h.

DNApod: DNA polymorphism annotation database from next-generation sequence read archives.

PubMed

Mochizuki, Takako; Tanizawa, Yasuhiro; Fujisawa, Takatomo; Ohta, Tazro; Nikoh, Naruo; Shimizu, Tokurou; Toyoda, Atsushi; Fujiyama, Asao; Kurata, Nori; Nagasaki, Hideki; Kaminuma, Eli; Nakamura, Yasukazu

2017-01-01

With the rapid advances in next-generation sequencing (NGS), datasets for DNA polymorphisms among various species and strains have been produced, stored, and distributed. However, reliability varies among these datasets because the experimental and analytical conditions used differ among assays. Furthermore, such datasets have been frequently distributed from the websites of individual sequencing projects. It is desirable to integrate DNA polymorphism data into one database featuring uniform quality control that is distributed from a single platform at a single place. DNA polymorphism annotation database (DNApod; http://tga.nig.ac.jp/dnapod/) is an integrated database that stores genome-wide DNA polymorphism datasets acquired under uniform analytical conditions, and this includes uniformity in the quality of the raw data, the reference genome version, and evaluation algorithms. DNApod genotypic data are re-analyzed whole-genome shotgun datasets extracted from sequence read archives, and DNApod distributes genome-wide DNA polymorphism datasets and known-gene annotations for each DNA polymorphism. This new database was developed for storing genome-wide DNA polymorphism datasets of plants, with crops being the first priority. Here, we describe our analyzed data for 679, 404, and 66 strains of rice, maize, and sorghum, respectively. The analytical methods are available as a DNApod workflow in an NGS annotation system of the DNA Data Bank of Japan and a virtual machine image. Furthermore, DNApod provides tables of links of identifiers between DNApod genotypic data and public phenotypic data. To advance the sharing of organism knowledge, DNApod offers basic and ubiquitous functions for multiple alignment and phylogenetic tree construction by using orthologous gene information.

DNApod: DNA polymorphism annotation database from next-generation sequence read archives

PubMed Central

Mochizuki, Takako; Tanizawa, Yasuhiro; Fujisawa, Takatomo; Ohta, Tazro; Nikoh, Naruo; Shimizu, Tokurou; Toyoda, Atsushi; Fujiyama, Asao; Kurata, Nori; Nagasaki, Hideki; Kaminuma, Eli; Nakamura, Yasukazu

2017-01-01

With the rapid advances in next-generation sequencing (NGS), datasets for DNA polymorphisms among various species and strains have been produced, stored, and distributed. However, reliability varies among these datasets because the experimental and analytical conditions used differ among assays. Furthermore, such datasets have been frequently distributed from the websites of individual sequencing projects. It is desirable to integrate DNA polymorphism data into one database featuring uniform quality control that is distributed from a single platform at a single place. DNA polymorphism annotation database (DNApod; http://tga.nig.ac.jp/dnapod/) is an integrated database that stores genome-wide DNA polymorphism datasets acquired under uniform analytical conditions, and this includes uniformity in the quality of the raw data, the reference genome version, and evaluation algorithms. DNApod genotypic data are re-analyzed whole-genome shotgun datasets extracted from sequence read archives, and DNApod distributes genome-wide DNA polymorphism datasets and known-gene annotations for each DNA polymorphism. This new database was developed for storing genome-wide DNA polymorphism datasets of plants, with crops being the first priority. Here, we describe our analyzed data for 679, 404, and 66 strains of rice, maize, and sorghum, respectively. The analytical methods are available as a DNApod workflow in an NGS annotation system of the DNA Data Bank of Japan and a virtual machine image. Furthermore, DNApod provides tables of links of identifiers between DNApod genotypic data and public phenotypic data. To advance the sharing of organism knowledge, DNApod offers basic and ubiquitous functions for multiple alignment and phylogenetic tree construction by using orthologous gene information. PMID:28234924

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolotnikov, A. E.; Camarda, G. S.; Cui, Y.

Following our successful demonstration of the position-sensitive virtual Frisch-grid detectors, we investigated the feasibility of using high-granularity position sensing to correct response non-uniformities caused by the crystal defects in CdZnTe (CZT) pixelated detectors. The development of high-granularity detectors able to correct response non-uniformities on a scale comparable to the size of electron clouds opens the opportunity of using unselected off-the-shelf CZT material, whilst still assuring high spectral resolution for the majority of the detectors fabricated from an ingot. Here, we present the results from testing 3D position-sensitive 15×15×10 mm 3 pixelated detectors, fabricated with conventional pixel patterns with progressively smallermore » pixel sizes: 1.4, 0.8, and 0.5 mm. We employed the readout system based on the H3D front-end multi-channel ASIC developed by BNL's Instrumentation Division in collaboration with the University of Michigan. We use the sharing of electron clouds among several adjacent pixels to measure locations of interaction points with sub-pixel resolution. By using the detectors with small-pixel sizes and a high probability of the charge-sharing events, we were able to improve their spectral resolutions in comparison to the baseline levels, measured for the 1.4-mm pixel size detectors with small fractions of charge-sharing events. These results demonstrate that further enhancement of the performance of CZT pixelated detectors and reduction of costs are possible by using high spatial-resolution position information of interaction points to correct the small-scale response non-uniformities caused by crystal defects present in most devices.« less

Alongshore Momentum Balance Over Shoreface-Connected Ridges, Fire Island, NY

NASA Astrophysics Data System (ADS)

Ofsthun, C.; Wu, X.; Voulgaris, G.; Warner, J. C.

2016-12-01

he momentum balance of alongshore flows over straight, uniform shelfs has been analyzed extensively over the last few decades. More recently, the effect of coastline curvature and how this might alter the relative significance of the momentum terms has received additional attention. In this contribution, the alongshore momentum over shelves with straight coastline, but non-uniform bathymetry is examined. Hydrodynamic and hydrographic data collected by the US Geological Survey (Fire Island Coastal Change project) on the inner shelf of Fire Island, NY over a region of shore-face connected ridges (SFCRs) are used to describe wind-induced circulation and the terms of the alongshore momentum balance equation. Analysis of the data revealed a predominantly alongshore circulation, under westward wind forcing, with localized offshore (onshore) current veering over the ridge crests (troughs). Momentum balance analysis hinted that local acceleration, advective acceleration, and bottom stress are balanced by wind stress and regional (>100 km) pressure gradient force. In addition, a numerical model using an idealized SFCR bathymetry, forced by our observed winds, was employed to compare the momentum balance relationships identified by the data and those under steady-state conditions published earlier (Warner et al., 2014). A synthesis of the numerical and experimental data revealed that the true pressure gradient force results from the sum of local pressure gradient force, which maintains a Bernoulli-like relationship with alongshore advective acceleration, and regional pressure gradient force, which maintains a strong, negative relationship with wind stress. The differences between steady-state and realistic conditions is mainly on the contributions of regional scale pressure gradients that develop under realistic conditions, and the reduced contribution of local scale pressure gradients which develop best under steady-state conditions. Our analysis indicates that current veering over ridge crests, a consistent occurrence, is a combination of a cross-shore gradient in the inconsistent relationship between local advective acceleration and pressure gradient and frictional-torque with the latter being the dominant mechanism under realistic forcing.

Isolation of Circulating Tumor Cells in an Orthotopic Mouse Model of Colorectal Cancer.

PubMed

Kochall, Susan; Thepkaysone, May-Linn; García, Sebastián A; Betzler, Alexander M; Weitz, Jürgen; Reissfelder, Christoph; Schölch, Sebastian

2017-07-18

Despite the advantages of easy applicability and cost-effectiveness, subcutaneous mouse models have severe limitations and do not accurately simulate tumor biology and tumor cell dissemination. Orthotopic mouse models have been introduced to overcome these limitations; however, such models are technically demanding, especially in hollow organs such as the large bowel. In order to produce uniform tumors which reliably grow and metastasize, standardized techniques of tumor cell preparation and injection are critical. We have developed an orthotopic mouse model of colorectal cancer (CRC) which develops highly uniform tumors and can be used for tumor biology studies as well as therapeutic trials. Tumor cells from either primary tumors, 2-dimensional (2D) cell lines or 3-dimensional (3D) organoids are injected into the cecum and, depending on the metastatic potential of the injected tumor cells, form highly metastatic tumors. In addition, CTCs can be found regularly. We here describe the technique of tumor cell preparation from both 2D cell lines and 3D organoids as well as primary tumor tissue, the surgical and injection techniques as well as the isolation of CTCs from the tumor-bearing mice, and present tips for troubleshooting.

Mesoporous transition metal oxides quasi-nanospheres with enhanced electrochemical properties for supercapacitor applications.

PubMed

Wang, Lu; Duan, Guorong; Zhu, Junwu; Chen, Shen-Ming; Liu, Xiao-Heng; Palanisamy, Selvakumar

2016-12-01

In this report, we obtain mesoporous transition metal oxides quasi-nanospheres (includes MnO2, NiO, and Co3O4) by utilizing mesoporous silica nanospheres as a template for high-performance supercapacitor electrodes. All samples have a large specific surface area of approximately 254-325m(2)g(-1) and a relatively narrow pore size distribution in the region of 7nm. Utilization of a nanosized template resulted in a product with a relative uniform morphology and a small particle diameter in the region of 50-100nm. As supercapacitor electrodes, MnO2, NiO, and Co3O4 exhibit an outstanding capacity as high as 838-1185Fg(-1) at 0.5Ag(-1) and a superior long-term stability with minimal loss of 3-7% after 6000 cycles at 1Ag(-1). Their excellent electrochemical performances are attributed to favorable morphologies with a large surface area and a uniform architecture with abundant pores. The associated enhancement of electrolyte ion circulation within the electrode facilitates a significant increase in availability of Faradic reaction electroactive sites. Copyright © 2016 Elsevier Inc. All rights reserved.

Application of State Quantization-Based Methods in HEP Particle Transport Simulation

NASA Astrophysics Data System (ADS)

Santi, Lucio; Ponieman, Nicolás; Jun, Soon Yung; Genser, Krzysztof; Elvira, Daniel; Castro, Rodrigo

2017-10-01

Simulation of particle-matter interactions in complex geometries is one of the main tasks in high energy physics (HEP) research. An essential aspect of it is an accurate and efficient particle transportation in a non-uniform magnetic field, which includes the handling of volume crossings within a predefined 3D geometry. Quantized State Systems (QSS) is a family of numerical methods that provides attractive features for particle transportation processes, such as dense output (sequences of polynomial segments changing only according to accuracy-driven discrete events) and lightweight detection and handling of volume crossings (based on simple root-finding of polynomial functions). In this work we present a proof-of-concept performance comparison between a QSS-based standalone numerical solver and an application based on the Geant4 simulation toolkit, with its default Runge-Kutta based adaptive step method. In a case study with a charged particle circulating in a vacuum (with interactions with matter turned off), in a uniform magnetic field, and crossing up to 200 volume boundaries twice per turn, simulation results showed speedups of up to 6 times in favor of QSS while it being 10 times slower in the case with zero volume boundaries.

The global impact distribution of Near-Earth objects

NASA Astrophysics Data System (ADS)

Rumpf, Clemens; Lewis, Hugh G.; Atkinson, Peter M.

2016-02-01

Asteroids that could collide with the Earth are listed on the publicly available Near-Earth object (NEO) hazard web sites maintained by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The impact probability distribution of 69 potentially threatening NEOs from these lists that produce 261 dynamically distinct impact instances, or Virtual Impactors (VIs), were calculated using the Asteroid Risk Mitigation and Optimization Research (ARMOR) tool in conjunction with OrbFit. ARMOR projected the impact probability of each VI onto the surface of the Earth as a spatial probability distribution. The projection considers orbit solution accuracy and the global impact probability. The method of ARMOR is introduced and the tool is validated against two asteroid-Earth collision cases with objects 2008 TC3 and 2014 AA. In the analysis, the natural distribution of impact corridors is contrasted against the impact probability distribution to evaluate the distributions' conformity with the uniform impact distribution assumption. The distribution of impact corridors is based on the NEO population and orbital mechanics. The analysis shows that the distribution of impact corridors matches the common assumption of uniform impact distribution and the result extends the evidence base for the uniform assumption from qualitative analysis of historic impact events into the future in a quantitative way. This finding is confirmed in a parallel analysis of impact points belonging to a synthetic population of 10,006 VIs. Taking into account the impact probabilities introduced significant variation into the results and the impact probability distribution, consequently, deviates markedly from uniformity. The concept of impact probabilities is a product of the asteroid observation and orbit determination technique and, thus, represents a man-made component that is largely disconnected from natural processes. It is important to consider impact probabilities because such information represents the best estimate of where an impact might occur.

Intercomparison of methods of coupling between convection and large-scale circulation. 1. Comparison over uniform surface conditions

DOE PAGES

Daleu, C. L.; Plant, R. S.; Woolnough, S. J.; ...

2015-10-24

Here, as part of an international intercomparison project, a set of single-column models (SCMs) and cloud-resolving models (CRMs) are run under the weak-temperature gradient (WTG) method and the damped gravity wave (DGW) method. For each model, the implementation of the WTG or DGW method involves a simulated column which is coupled to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. The simulated column has the same surface conditions as the reference state and is initialized with profiles from the reference state. We performed systematic comparison of the behavior of different models under a consistentmore » implementation of the WTG method and the DGW method and systematic comparison of the WTG and DGW methods in models with different physics and numerics. CRMs and SCMs produce a variety of behaviors under both WTG and DGW methods. Some of the models reproduce the reference state while others sustain a large-scale circulation which results in either substantially lower or higher precipitation compared to the value of the reference state. CRMs show a fairly linear relationship between precipitation and circulation strength. SCMs display a wider range of behaviors than CRMs. Some SCMs under the WTG method produce zero precipitation. Within an individual SCM, a DGW simulation and a corresponding WTG simulation can produce different signed circulation. When initialized with a dry troposphere, DGW simulations always result in a precipitating equilibrium state. The greatest sensitivities to the initial moisture conditions occur for multiple stable equilibria in some WTG simulations, corresponding to either a dry equilibrium state when initialized as dry or a precipitating equilibrium state when initialized as moist. Multiple equilibria are seen in more WTG simulations for higher SST. In some models, the existence of multiple equilibria is sensitive to some parameters in the WTG calculations.« less

Acoustic Characterization and Enhanced Ultrasound Imaging of Long-Circulating Lipid-Coated Microbubbles.

PubMed

Li, Hongbo; Yang, Yanye; Zhang, Meimei; Yin, Liping; Tu, Juan; Guo, Xiasheng; Zhang, Dong

2018-05-01

A long-circulating lipid-coated ultrasound (US) contrast agent was fabricated to achieve a longer wash-out time and gain more resistance against higher-mechanical index sonication. Systemic physical, acoustic, and in vivo imaging experiments were performed to better understand the underlying mechanism enabling the improvement of contrast agent performance by adjusting the physical and acoustic properties of contrast agent microbubbles. By simply altering the gas core, a kind of US contrast agent microbubble was synthesized with a similar lipid-coating shell as SonoVue microbubbles (Bracco SpA, Milan, Italy) to achieve a longer wash-out time and higher inertial cavitation threshold. To bridge the structure-performance relationship of the synthesized microbubbles, the imaging performance of the microbubbles was assessed in vivo with SonoVue as a control group. The size distribution and inertial cavitation threshold of the synthesized microbubbles were characterized, and the shell parameters of the microbubbles were determined by acoustic attenuation measurements. All of the measurements were compared with SonoVue microbubbles. The synthesized microbubbles had a spherical shape, a smooth, consistent membrane, and a uniform distribution, with an average diameter of 1.484 μm. According to the measured attenuation curve, the synthesized microbubbles resonated at around 2.8 MHz. Although the bubble's shell elasticity (0.2 ± 0.09 N/m) was comparable with SonoVue, it had relatively greater viscosity and inertial cavitation because of the different gas core. Imaging studies showed that the synthesized microbubbles had a longer circulation time and a better chance of fighting against rapid collapse than SonoVue. Nano/micrometer long-circulating lipid-coated microbubbles could be fabricated by simply altering the core composition of SonoVue microbubbles with a higher-molecular weight gas. The smaller diameter and higher inertial cavitation threshold of the synthesized microbubbles might make it easier to access deep-seated organs and give prolonged imaging enhancement in the liver. © 2017 by the American Institute of Ultrasound in Medicine.

Growing water scarcity in agriculture: future challenge to global water security.

PubMed

Falkenmark, Malin

2013-11-13

As water is an essential component of the planetary life support system, water deficiency constitutes an insecurity that has to be overcome in the process of socio-economic development. The paper analyses the origin and appearance of blue as well as green water scarcity on different scales and with particular focus on risks to food production and water supply for municipalities and industry. It analyses water scarcity originating from both climatic phenomena and water partitioning disturbances on different scales: crop field, country level and the global circulation system. The implications by 2050 of water scarcity in terms of potential country-level water deficits for food self-reliance are analysed, and the compensating dependence on trade in virtual water for almost half the world population is noted. Planetary-scale conditions for sustainability of the global water circulation system are discussed in terms of a recently proposed Planetary Freshwater Boundary, and the consumptive water use reserve left to be shared between water requirements for global food production, fuelwood production and carbon sequestration is discussed. Finally, the importance of a paradigm shift in the further conceptual development of water security is stressed, so that adequate attention is paid to water's fundamental role in both natural and socio-economic systems.

Long-circulating Janus nanoparticles made by electrohydrodynamic co-jetting for systemic drug delivery applications

PubMed Central

Rahmani, Sahar; Villa, Carlos H.; Dishman, Acacia F.; Grabowski, Marika E.; Pan, Daniel C.; Durmaz, Hakan; Misra, Asish C; Colón-Meléndez, Laura; Solomon, Michael J.; Muzykantov, Vladimir R.; Lahann, Joerg

2016-01-01

Background Nanoparticles with controlled physical properties have been widely used for controlled release applications. In addition to shape, the anisotropic nature of the particles can be an important design criterion to ensure selective surface modification or independent release of combinations of drugs. Purpose Electrohydrodynamic (EHD) co-jetting is used for the fabrication of uniform anisotropic nanoparticles with individual compartments and initial physicochemical and biological characterization is reported. Methods EHD co-jetting is used to create nanoparticles, which are characterized at each stage with scanning electron microscopy (SEM), structured illumination microscopy (SIM), dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). Surface immobilization techniques are used to incorporate polyethylene glycol (PEG) and I125 radiolabels into the nanoparticles. Particles are injected in mice and the particle distribution after 1, 4 and 24 hours is assessed. Results and discussion Nanoparticles with an average diameter of 105.7 nm are prepared by EHD co-jetting. The particles contain functional chemical groups for further surface modification and radiolabeling. The density of PEG molecules attached to the surface of nanoparticles is determined to range between 0.02 and 6.04 ligands per square nanometer. A significant fraction of the nanoparticles (1.2% injected dose per mass of organ) circulates in the blood after 24 h. Conclusion EHD co-jetting is a versatile method for the fabrication of nanoparticles for drug delivery. Circulation of the nanoparticles for 24 h is a pre-requisite for subsequent studies to explore defined targeting of the nanoparticles to a specific anatomic site. PMID:26453170

Asynchronous warming and δ 18O evolution of deep Atlantic water masses during the last deglaciation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jiaxu; Liu, Zhengyu; Brady, Esther C.

The large-scale reorganization of deep ocean circulation in the Atlantic involving changes in North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) played a critical role in regulating hemispheric and global climate during the last deglaciation. However, changes in the relative contributions of NADW and AABW and their properties are poorly constrained by marine records, including δ 18O of benthic foraminiferal calcite (δ 18Oc). Here in this study, we use an isotope-enabled ocean general circulation model with realistic geometry and forcing conditions to simulate the deglacial water mass and δ 18O evolution. Model results suggest that, in response tomore » North Atlantic freshwater forcing during the early phase of the last deglaciation, NADW nearly collapses, while AABW mildly weakens. Rather than reflecting changes in NADW or AABW properties caused by freshwater input as suggested previously, the observed phasing difference of deep δ 18O c likely reflects early warming of the deep northern North Atlantic by ~1.4 °C, while deep Southern Ocean temperature remains largely unchanged. We propose a thermodynamic mechanism to explain the early warming in the North Atlantic, featuring a strong middepth warming and enhanced downward heat flux via vertical mixing. Our results emphasize that the way that ocean circulation affects heat, a dynamic tracer, is considerably different from how it affects passive tracers, like δ 18O, and call for caution when inferring water mass changes from δ 18O c records while assuming uniform changes in deep temperatures.« less

Passive shut-down heat removal system

DOEpatents

Hundal, Rolv; Sharbaugh, John E.

1988-01-01

An improved shut-down heat removal system for a liquid metal nuclear reactor of the type having a vessel for holding hot and cold pools of liquid sodium is disclosed herein. Generally, the improved system comprises a redan or barrier within the reactor vessel which allows an auxiliary heat exchanger to become immersed in liquid sodium from the hot pool whenever the reactor pump fails to generate a metal-circulating pressure differential between the hot and cold pools of sodium. This redan also defines an alternative circulation path between the hot and cold pools of sodium in order to equilibrate the distribution of the decay heat from the reactor core. The invention may take the form of a redan or barrier that circumscribes the inner wall of the reactor vessel, thereby defining an annular space therebetween. In this embodiment, the bottom of the annular space communicates with the cold pool of sodium, and the auxiliary heat exchanger is placed in this annular space just above the drawn-down level that the liquid sodium assumes during normal operating conditions. Alternatively, the redan of the invention may include a pair of vertically oriented, concentrically disposed standpipes having a piston member disposed between them that operates somewhat like a pressure-sensitive valve. In both embodiments, the cessation of the pressure differential that is normally created by the reactor pump causes the auxiliary heat exchanger to be immersed in liquid sodium from the hot pool. Additionally, the redan in both embodiments forms a circulation flow path between the hot and cold pools so that the decay heat from the nuclear core is uniformly distributed within the vessel.

Asynchronous warming and δ18O evolution of deep Atlantic water masses during the last deglaciation.

PubMed

Zhang, Jiaxu; Liu, Zhengyu; Brady, Esther C; Oppo, Delia W; Clark, Peter U; Jahn, Alexandra; Marcott, Shaun A; Lindsay, Keith

2017-10-17

The large-scale reorganization of deep ocean circulation in the Atlantic involving changes in North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) played a critical role in regulating hemispheric and global climate during the last deglaciation. However, changes in the relative contributions of NADW and AABW and their properties are poorly constrained by marine records, including δ 18 O of benthic foraminiferal calcite (δ 18 O c ). Here, we use an isotope-enabled ocean general circulation model with realistic geometry and forcing conditions to simulate the deglacial water mass and δ 18 O evolution. Model results suggest that, in response to North Atlantic freshwater forcing during the early phase of the last deglaciation, NADW nearly collapses, while AABW mildly weakens. Rather than reflecting changes in NADW or AABW properties caused by freshwater input as suggested previously, the observed phasing difference of deep δ 18 O c likely reflects early warming of the deep northern North Atlantic by ∼1.4 °C, while deep Southern Ocean temperature remains largely unchanged. We propose a thermodynamic mechanism to explain the early warming in the North Atlantic, featuring a strong middepth warming and enhanced downward heat flux via vertical mixing. Our results emphasize that the way that ocean circulation affects heat, a dynamic tracer, is considerably different from how it affects passive tracers, like δ 18 O, and call for caution when inferring water mass changes from δ 18 O c records while assuming uniform changes in deep temperatures.

Arterial grafts exhibiting unprecedented cellular infiltration and remodeling in vivo: the role of cells in the vascular wall.

PubMed

Row, Sindhu; Peng, Haofan; Schlaich, Evan M; Koenigsknecht, Carmon; Andreadis, Stelios T; Swartz, Daniel D

2015-05-01

To engineer and implant vascular grafts in the arterial circulation of a pre-clinical animal model and assess the role of donor medial cells in graft remodeling and function. Vascular grafts were engineered using Small Intestinal Submucosa (SIS)-fibrin hybrid scaffold and implanted interpositionally into the arterial circulation of an ovine model. We sought to demonstrate implantability of SIS-Fibrin based grafts; examine the remodeling; and determine whether the presence of vascular cells in the medial wall was necessary for cellular infiltration from the host and successful remodeling of the implants. We observed no occlusions or anastomotic complications in 18 animals that received these grafts. Notably, the grafts exhibited unprecedented levels of host cell infiltration that was not limited to the anastomotic sites but occurred through the lumen as well as the extramural side, leading to uniform cell distribution. Incoming cells remodeled the extracellular matrix and matured into functional smooth muscle cells as evidenced by expression of myogenic markers and development of vascular reactivity. Interestingly, tracking the donor cells revealed that their presence was beneficial but not necessary for successful grafting. Indeed, the proliferation rate and number of donor cells decreased over time as the vascular wall was dominated by host cells leading to significant remodeling and development of contractile function. These results demonstrate that SIS-Fibrin grafts can be successfully implanted into the arterial circulation of a clinically relevant animal model, improve our understanding of vascular graft remodeling and raise the possibility of engineering mural cell-free arterial grafts. Copyright © 2015 Elsevier Ltd. All rights reserved.

Asynchronous warming and δ 18O evolution of deep Atlantic water masses during the last deglaciation

DOE PAGES

Zhang, Jiaxu; Liu, Zhengyu; Brady, Esther C.; ...

2017-10-02

The large-scale reorganization of deep ocean circulation in the Atlantic involving changes in North Atlantic Deep Water (NADW) and Antarctic Bottom Water (AABW) played a critical role in regulating hemispheric and global climate during the last deglaciation. However, changes in the relative contributions of NADW and AABW and their properties are poorly constrained by marine records, including δ 18O of benthic foraminiferal calcite (δ 18Oc). Here in this study, we use an isotope-enabled ocean general circulation model with realistic geometry and forcing conditions to simulate the deglacial water mass and δ 18O evolution. Model results suggest that, in response tomore » North Atlantic freshwater forcing during the early phase of the last deglaciation, NADW nearly collapses, while AABW mildly weakens. Rather than reflecting changes in NADW or AABW properties caused by freshwater input as suggested previously, the observed phasing difference of deep δ 18O c likely reflects early warming of the deep northern North Atlantic by ~1.4 °C, while deep Southern Ocean temperature remains largely unchanged. We propose a thermodynamic mechanism to explain the early warming in the North Atlantic, featuring a strong middepth warming and enhanced downward heat flux via vertical mixing. Our results emphasize that the way that ocean circulation affects heat, a dynamic tracer, is considerably different from how it affects passive tracers, like δ 18O, and call for caution when inferring water mass changes from δ 18O c records while assuming uniform changes in deep temperatures.« less

Optimizing Aerobot Exploration of Venus

NASA Astrophysics Data System (ADS)

Ford, Kevin S.

1997-03-01

Venus Flyer Robot (VFR) is an aerobot; an autonomous balloon probe designed for remote exploration of Earth's sister planet in 2003. VFR's simple navigation and control system permits travel to virtually any location on Venus, but it can survive for only a limited duration in the harsh Venusian environment. To help address this limitation, we develop: (1) a global circulation model that captures the most important characteristics of the Venusian atmosphere; (2) a simple aerobot model that captures thermal restrictions faced by VFR at Venus; and (3) one exact and two heuristic algorithms that, using abstractions (1) and (2), construct routes making the best use of VFR's limited lifetime. We demonstrate this modeling by planning several small example missions and a prototypical mission that explores numerous interesting sites recently documented in the plane tary geology literature.

Optimizing Aerobot Exploration of Venus

NASA Technical Reports Server (NTRS)

Ford, Kevin S.

1997-01-01

Venus Flyer Robot (VFR) is an aerobot; an autonomous balloon probe designed for remote exploration of Earth's sister planet in 2003. VFR's simple navigation and control system permits travel to virtually any location on Venus, but it can survive for only a limited duration in the harsh Venusian environment. To help address this limitation, we develop: (1) a global circulation model that captures the most important characteristics of the Venusian atmosphere; (2) a simple aerobot model that captures thermal restrictions faced by VFR at Venus; and (3) one exact and two heuristic algorithms that, using abstractions (1) and (2), construct routes making the best use of VFR's limited lifetime. We demonstrate this modeling by planning several small example missions and a prototypical mission that explores numerous interesting sites recently documented in the plane tary geology literature.

Seasonal Distributions of Global Ocean Chlorophyll and Nutrients: Analysis with a Coupled Ocean General Circulation Biogeochemical, and Radiative Model

NASA Technical Reports Server (NTRS)

Gregg, Watson W.

1999-01-01

A coupled general ocean circulation, biogeochemical, and radiative model was constructed to evaluate and understand the nature of seasonal variability of chlorophyll and nutrients in the global oceans. The model is driven by climatological meteorological conditions, cloud cover, and sea surface temperature. Biogeochemical processes in the model are determined from the influences of circulation and turbulence dynamics, irradiance availability, and the interactions among three functional phytoplankton groups (diatoms, chorophytes, and picoplankton) and three nutrient groups (nitrate, ammonium, and silicate). Phytoplankton groups are initialized as homogeneous fields horizontally and vertically, and allowed to distribute themselves according to the prevailing conditions. Basin-scale model chlorophyll results are in very good agreement with CZCS pigments in virtually every global region. Seasonal variability observed in the CZCS is also well represented in the model. Synoptic scale (100-1000 km) comparisons of imagery are also in good conformance, although occasional departures are apparent. Agreement of nitrate distributions with in situ data is even better, including seasonal dynamics, except for the equatorial Atlantic. The good agreement of the model with satellite and in situ data sources indicates that the model dynamics realistically simulate phytoplankton and nutrient dynamics on synoptic scales. This is especially true given that initial conditions are homogenous chlorophyll fields. The success of the model in producing a reasonable representation of chlorophyll and nutrient distributions and seasonal variability in the global oceans is attributed to the application of a generalized, processes-driven approach as opposed to regional parameterization, and the existence of multiple phytoplankton groups with different physiological and physical properties. These factors enable the model to simultaneously represent the great diversity of physical, biological, chemical, and radiative environments encountered in the global oceans.

Distance education through the Internet: the GNA-VSNS biocomputing course.

PubMed

de la Vega, F M; Giegerich, R; Fuellen, G

1996-01-01

A prototype course on biocomputing was delivered via international computer networks in early summer 1995. The course lasted 11 weeks, and was offered free of charge. It was organized by the BioComputing Division of the Virtual School of Natural Sciences, which is a member school of the Globewide Network Academy. It brought together 34 students and 7 instructors from all over the world, and covered the basics of sequence analysis. Five authors from Germany and USA prepared a hypertext book which was discussed in weekly study sessions that took place in a virtual classroom at the BioMOO electronic conferencing system. The course aimed at students with backgrounds in molecular biology, biomedicine or computer science, complementing and extending their skills with an interdisciplinary curriculum. Special emphasis was placed on the use of Internet resources, and the development of new teaching tools. The hypertext book includes direct links to sequence analysis and databank search services on the Internet. A tool for the interactive visualization of unit-cost pairwise sequence alignment was developed for the course. All course material will stay accessible at the World Wide Web address (Uniform Resource Locator) http://+www.techfak.uni-bielefeld.de/bcd/welcome .html. This paper describes the aims and organization of the course, and gives a preliminary account of this novel experience in distance education.

Virtual Planning, Control, and Machining for a Modular-Based Automated Factory Operation in an Augmented Reality Environment

PubMed Central

Pai, Yun Suen; Yap, Hwa Jen; Md Dawal, Siti Zawiah; Ramesh, S.; Phoon, Sin Ye

2016-01-01

This study presents a modular-based implementation of augmented reality to provide an immersive experience in learning or teaching the planning phase, control system, and machining parameters of a fully automated work cell. The architecture of the system consists of three code modules that can operate independently or combined to create a complete system that is able to guide engineers from the layout planning phase to the prototyping of the final product. The layout planning module determines the best possible arrangement in a layout for the placement of various machines, in this case a conveyor belt for transportation, a robot arm for pick-and-place operations, and a computer numerical control milling machine to generate the final prototype. The robotic arm module simulates the pick-and-place operation offline from the conveyor belt to a computer numerical control (CNC) machine utilising collision detection and inverse kinematics. Finally, the CNC module performs virtual machining based on the Uniform Space Decomposition method and axis aligned bounding box collision detection. The conducted case study revealed that given the situation, a semi-circle shaped arrangement is desirable, whereas the pick-and-place system and the final generated G-code produced the highest deviation of 3.83 mm and 5.8 mm respectively. PMID:27271840

Environmental continuous air monitor inlet with combined preseparator and virtual impactor

DOEpatents

Rodgers, John C [Santa Fe, NM

2007-06-19

An inlet for an environmental air monitor is described wherein a pre-separator interfaces with ambient environment air and removes debris and insects commonly associated with high wind outdoors and a deflector plate in communication with incoming air from the pre-separator stage, that directs the air radially and downward uniformly into a plurality of accelerator jets located in a manifold of a virtual impactor, the manifold being cylindrical and having a top, a base, and a wall, with the plurality of accelerator jets being located in the top of the manifold and receiving the directed air and accelerating directed air, thereby creating jets of air penetrating into the manifold, where a major flow is deflected to the walls of the manifold and extracted through ports in the walls. A plurality of receiver nozzles are located in the base of the manifold coaxial with the accelerator jets, and a plurality of matching flow restrictor elements are located in the plurality of receiver nozzles for balancing and equalizing the total minor flow among all the plurality of receiver nozzles, through which a lower, fractional flow extracts large particle constituents of the air for collection on a sample filter after passing through the plurality of receiver nozzles and the plurality of matching flow restrictor elements.

Energy gain calculations in spherical IEC fusion systems using the BAFP code

NASA Astrophysics Data System (ADS)

Chacón, L.; Miley, G. H.; Barnes, D. C.; Knoll, D. A.

1999-11-01

The spherical IEC fusion concept takes advantage of the potential well generated by an inner spherical cathode (physical or virtual), biased negatively to several kV with respect to a concentric outer grounded boundary, to focus ions inwards and form a dense central core where fusion may occur. However, defocusing of the ion beams due to ion-ion collisions may prevent a satisfactory energy balance in the system. This research concentrates of spherically symmetric virtual cathode IEC devices, in which a spherical cloud of electrons, confined á la Penning trap, creates the ion-confining electrostatic well. A bounce-averaged Fokker-Planck model has been constructed to analyze the ion physics in ideal conditions (i.e., spherically uniform electrostatic well, no collisional interaction between ions and electrons, single ion species).(L. Chacon, D. C. Barnes, D. A. Knoll, 40^th) Annual Meeting of the APS Division of Plasma Physics, New Orleans, LA, Nov. 1998 Results will reproduce the phenomenology of previously published( W. Nevins, Phys. Plasmas), 2(10), 3804-3819 (1995) theoretical limits, and will show that, under some conditions, steady-state solutions with relatively high gains and small ion recirculation powers exist for the bounce-averaged Fokker-Planck transport equation. Variations in gain with parameter space will be presented.

Virtual Planning, Control, and Machining for a Modular-Based Automated Factory Operation in an Augmented Reality Environment.

PubMed

Pai, Yun Suen; Yap, Hwa Jen; Md Dawal, Siti Zawiah; Ramesh, S; Phoon, Sin Ye

2016-06-07

This study presents a modular-based implementation of augmented reality to provide an immersive experience in learning or teaching the planning phase, control system, and machining parameters of a fully automated work cell. The architecture of the system consists of three code modules that can operate independently or combined to create a complete system that is able to guide engineers from the layout planning phase to the prototyping of the final product. The layout planning module determines the best possible arrangement in a layout for the placement of various machines, in this case a conveyor belt for transportation, a robot arm for pick-and-place operations, and a computer numerical control milling machine to generate the final prototype. The robotic arm module simulates the pick-and-place operation offline from the conveyor belt to a computer numerical control (CNC) machine utilising collision detection and inverse kinematics. Finally, the CNC module performs virtual machining based on the Uniform Space Decomposition method and axis aligned bounding box collision detection. The conducted case study revealed that given the situation, a semi-circle shaped arrangement is desirable, whereas the pick-and-place system and the final generated G-code produced the highest deviation of 3.83 mm and 5.8 mm respectively.

Virtual Planning, Control, and Machining for a Modular-Based Automated Factory Operation in an Augmented Reality Environment

NASA Astrophysics Data System (ADS)

Pai, Yun Suen; Yap, Hwa Jen; Md Dawal, Siti Zawiah; Ramesh, S.; Phoon, Sin Ye

2016-06-01

This study presents a modular-based implementation of augmented reality to provide an immersive experience in learning or teaching the planning phase, control system, and machining parameters of a fully automated work cell. The architecture of the system consists of three code modules that can operate independently or combined to create a complete system that is able to guide engineers from the layout planning phase to the prototyping of the final product. The layout planning module determines the best possible arrangement in a layout for the placement of various machines, in this case a conveyor belt for transportation, a robot arm for pick-and-place operations, and a computer numerical control milling machine to generate the final prototype. The robotic arm module simulates the pick-and-place operation offline from the conveyor belt to a computer numerical control (CNC) machine utilising collision detection and inverse kinematics. Finally, the CNC module performs virtual machining based on the Uniform Space Decomposition method and axis aligned bounding box collision detection. The conducted case study revealed that given the situation, a semi-circle shaped arrangement is desirable, whereas the pick-and-place system and the final generated G-code produced the highest deviation of 3.83 mm and 5.8 mm respectively.

Spatial resolution recovery utilizing multi-ray tracing and graphic processing unit in PET image reconstruction.

PubMed

Liang, Yicheng; Peng, Hao

2015-02-07

Depth-of-interaction (DOI) poses a major challenge for a PET system to achieve uniform spatial resolution across the field-of-view, particularly for small animal and organ-dedicated PET systems. In this work, we implemented an analytical method to model system matrix for resolution recovery, which was then incorporated in PET image reconstruction on a graphical processing unit platform, due to its parallel processing capacity. The method utilizes the concepts of virtual DOI layers and multi-ray tracing to calculate the coincidence detection response function for a given line-of-response. The accuracy of the proposed method was validated for a small-bore PET insert to be used for simultaneous PET/MR breast imaging. In addition, the performance comparisons were studied among the following three cases: 1) no physical DOI and no resolution modeling; 2) two physical DOI layers and no resolution modeling; and 3) no physical DOI design but with a different number of virtual DOI layers. The image quality was quantitatively evaluated in terms of spatial resolution (full-width-half-maximum and position offset), contrast recovery coefficient and noise. The results indicate that the proposed method has the potential to be used as an alternative to other physical DOI designs and achieve comparable imaging performances, while reducing detector/system design cost and complexity.

Education and Outreach with the Virtual Astronomical Observatory

NASA Astrophysics Data System (ADS)

Lawton, Brandon L.; Eisenhamer, B.; Raddick, M. J.; Mattson, B. J.; Harris, J.

2012-01-01

The Virtual Observatory (VO) is an international effort to bring a large-scale electronic integration of astronomy data, tools, and services to the global community. The Virtual Astronomical Observatory (VAO) is the U.S. NSF- and NASA-funded VO effort that seeks to put efficient astronomical tools in the hands of U.S. astronomers, students, educators, and public outreach leaders. These tools will make use of data collected by the multitude of ground- and space-based missions over the previous decades. Many future missions will also be incorporated into the VAO tools when they launch. The Education and Public Outreach (E/PO) program for the VAO is led by the Space Telescope Science Institute in collaboration with the HEASARC E/PO program and Johns Hopkins University. VAO E/PO efforts seek to bring technology, real-world astronomical data, and the story of the development and infrastructure of the VAO to the general public, formal education, and informal education communities. Our E/PO efforts will be structured to provide uniform access to VAO information, enabling educational opportunities across multiple wavelengths and time-series data sets. The VAO team recognizes that many VO programs have built powerful tools for E/PO purposes, such as Microsoft's World Wide Telescope, SDSS Sky Server, Aladin, and a multitude of citizen-science tools available from Zooniverse. We are building partnerships with Microsoft, Zooniverse, and NASA's Night Sky Network to leverage the communities and tools that already exist to meet the needs of our audiences. Our formal education program is standards-based and aims to give teachers the tools to use real astronomical data to teach the STEM subjects. To determine which tools the VAO will incorporate into the formal education program, needs assessments will be conducted with educators across the U.S.

Behavioral and Network Origins of Wealth Inequality: Insights from a Virtual World

PubMed Central

Fuchs, Benedikt; Thurner, Stefan

2014-01-01

Almost universally, wealth is not distributed uniformly within societies or economies. Even though wealth data have been collected in various forms for centuries, the origins for the observed wealth-disparity and social inequality are not yet fully understood. Especially the impact and connections of human behavior on wealth could so far not be inferred from data. Here we study wealth data from the virtual economy of the massive multiplayer online game (MMOG) Pardus. This data not only contains every player's wealth at every point in time, but also all actions over a timespan of almost a decade. We find that wealth distributions in the virtual world are very similar to those in Western countries. In particular we find an approximate exponential distribution for low wealth levels and a power-law tail for high levels. The Gini index is found to be , which is close to the indices of many Western countries. We find that wealth-increase rates depend on the time when players entered the game. Players that entered the game early on tend to have remarkably higher wealth-increase rates than those who joined later. Studying the players' positions within their social networks, we find that the local position in the trade network is most relevant for wealth. Wealthy people have high in- and out-degrees in the trade network, relatively low nearest-neighbor degrees, and low clustering coefficients. Wealthy players have many mutual friendships and are socially well respected by others, but spend more time on business than on socializing. Wealthy players have few personal enemies, but show animosity towards players that behave as public enemies. We find that players that are not organized within social groups are significantly poorer on average. We observe that “political” status and wealth go hand in hand. PMID:25153072

Behavioral and network origins of wealth inequality: insights from a virtual world.

PubMed

Fuchs, Benedikt; Thurner, Stefan

2014-01-01

Almost universally, wealth is not distributed uniformly within societies or economies. Even though wealth data have been collected in various forms for centuries, the origins for the observed wealth-disparity and social inequality are not yet fully understood. Especially the impact and connections of human behavior on wealth could so far not be inferred from data. Here we study wealth data from the virtual economy of the massive multiplayer online game (MMOG) Pardus. This data not only contains every player's wealth at every point in time, but also all actions over a timespan of almost a decade. We find that wealth distributions in the virtual world are very similar to those in Western countries. In particular we find an approximate exponential distribution for low wealth levels and a power-law tail for high levels. The Gini index is found to be g = 0.65, which is close to the indices of many Western countries. We find that wealth-increase rates depend on the time when players entered the game. Players that entered the game early on tend to have remarkably higher wealth-increase rates than those who joined later. Studying the players' positions within their social networks, we find that the local position in the trade network is most relevant for wealth. Wealthy people have high in- and out-degrees in the trade network, relatively low nearest-neighbor degrees, and low clustering coefficients. Wealthy players have many mutual friendships and are socially well respected by others, but spend more time on business than on socializing. Wealthy players have few personal enemies, but show animosity towards players that behave as public enemies. We find that players that are not organized within social groups are significantly poorer on average. We observe that "political" status and wealth go hand in hand.

Right heart failure: toward a common language.

PubMed

Mehra, Mandeep R; Park, Myung H; Landzberg, Michael J; Lala, Anuradha; Waxman, Aaron B

2014-02-01

In this perspective, the International Right Heart Foundation Working Group moves a step forward to develop a common language to describe the development and defects that exemplify the common syndrome of right heart failure. We first propose fundamental definitions of the distinctive components of the right heart circulation and provide consensus on a universal definition of right heart failure. These definitions will form the foundation for describing a uniform nomenclature for right heart circulatory failure with a view to foster collaborative research initiatives and conjoint education in an effort to provide insight into echanisms of disease unique to the right heart. © 2014 Published by International Society for the Heart and Lung Transplantation on behalf of International Society for Heart and Lung Transplantation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakaguchi, Koichi; Leung, Lai-Yung R.; Zhao, Chun

This study presents a diagnosis of a multi-resolution approach using the Model for Prediction Across Scales - Atmosphere (MPAS-A) for simulating regional climate. Four AMIP experiments are conducted for 1999-2009. In the first two experiments, MPAS-A is configured using global quasi-uniform grids at 120 km and 30 km grid spacing. In the other two experiments, MPAS-A is configured using variable-resolution (VR) mesh with local refinement at 30 km over North America and South America embedded inside a quasi-uniform domain at 120 km elsewhere. Precipitation and related fields in the four simulations are examined to determine how well the VR simulationsmore » reproduce the features simulated by the globally high-resolution model in the refined domain. In previous analyses of idealized aqua-planet simulations, the characteristics of the global high-resolution simulation in moist processes only developed near the boundary of the refined region. In contrast, the AMIP simulations with VR grids are able to reproduce the high-resolution characteristics across the refined domain, particularly in South America. This indicates the importance of finely resolved lower-boundary forcing such as topography and surface heterogeneity for the regional climate, and demonstrates the ability of the MPAS-A VR to replicate the large-scale moisture transport as simulated in the quasi-uniform high-resolution model. Outside of the refined domain, some upscale effects are detected through large-scale circulation but the overall climatic signals are not significant at regional scales. Our results provide support for the multi-resolution approach as a computationally efficient and physically consistent method for modeling regional climate.« less

Changes in the Martian Circulation and Climate in Response to Orbital Parameter Variations

NASA Astrophysics Data System (ADS)

Richardson, M. I.; Wilson, R. J.

2000-10-01

Martian orbital parameters are known to vary on time scales greater than 105 years. Such variations, especially in obliquity, have important consequences for the spatial distribution of solar heating of the surface and atmosphere, and hence are expected to affect some form of quasi-periodic climate change. The impact of changing obliquity on surface temperatures, and hence on volatile stability have been widely addressed. However, the changing insolation patterns should also modify the circulation of the atmosphere. As the nature and rate of volatile transport, and the vigour of dust lifting and transport from the surface are critical aspects of the climate, the circulation response to orbital variations needs to be assessed. In this presentation, we show results from the Geophysical Fluid Dynamics Laboratory (GFDL) Mars General Circulation Model (GCM) in which the orbit of Mars has been varied: obliquities between 0 and 60, perihelion passage between Ls=70 and 250, and eccentricities between 0 and 0.12. In general, the total atmosphere and cap CO2 budget is held constant (i.e. we assume no exchange with the regolith), and that the rate of dust supply into the lowest model level remains constant. The impact of these assumptions are examined. Many of the anticipated changes in circulation are found to occur as obliquity is increased from 0: The Hadley cell strength and that of the winter polar jet are found to increase; The magnitude of the seasonal CO2 cycle increases, resulting in extensive seasonal ice caps; Surface winds strengthen resulting in greater surface stresses and likely stronger dust lifting; The cycle of water becomes more vigourous, with large column vapour amounts in the polar regions corresponding to higher cap surface temperatures. However, some results contrast with expectations: Although the surface wind strengths change with orbital parameters, the mean directions tend not to, with implications for aeolian geological features; Even at low obliquity, the model does not develop a permanent CO2 ice cap at either pole (this likely reflects the fact that uniform and non-varying ice properties are gravely inadequate to realistically simulate Martian polar ices); Water ice deposits do not stabilize at the equator, even at high obliquity - instead they slosh backwards-and-forwards between the seasonal ice caps, as they do at present. We note that the southern summer Hadley circulation remains the dominant cell when integrated over the annual cycle, even when the timing of perihelion passage is varied by 180 degrees. We suggest that this reflects the greater importance of the global topographic dichotomy for the strength of the mean meridional circulation over that of eccentricity.

CROSS DRIVE: A New Interactive and Immersive Approach for Exploring 3D Time-Dependent Mars Atmospheric Data in Distributed Teams

NASA Astrophysics Data System (ADS)

Gerndt, Andreas M.; Engelke, Wito; Giuranna, Marco; Vandaele, Ann C.; Neary, Lori; Aoki, Shohei; Kasaba, Yasumasa; Garcia, Arturo; Fernando, Terrence; Roberts, David; CROSS DRIVE Team

2016-10-01

Atmospheric phenomena of Mars can be highly dynamic and have daily and seasonal variations. Planetary-scale wavelike disturbances, for example, are frequently observed in Mars' polar winter atmosphere. Possible sources of the wave activity were suggested to be dynamical instabilities and quasi-stationary planetary waves, i.e. waves that arise predominantly via zonally asymmetric surface properties. For a comprehensive understanding of these phenomena, single layers of altitude have to be analyzed carefully and relations between different atmospheric quantities and interaction with the surface of Mars have to be considered. The CROSS DRIVE project tries to address the presentation of those data with a global view by means of virtual reality techniques. Complex orbiter data from spectrometer and observation data from Earth are combined with global circulation models and high-resolution terrain data and images available from Mars Express or MRO instruments. Scientists can interactively extract features from those dataset and can change visualization parameters in real-time in order to emphasize findings. Stereoscopic views allow for perception of the actual 3D behavior of Mars's atmosphere. A very important feature of the visualization system is the possibility to connect distributed workspaces together. This enables discussions between distributed working groups. The workspace can scale from virtual reality systems to expert desktop applications to web-based project portals. If multiple virtual environments are connected, the 3D position of each individual user is captured and used to depict the scientist as an avatar in the virtual world. The appearance of the avatar can also scale from simple annotations to complex avatars using tele-presence technology to reconstruct the users in 3D. Any change of the feature set (annotations, cutplanes, volume rendering, etc.) within the VR is immediately exchanged between all connected users. This allows that everybody is always aware of what is visible and discussed. The discussion is supported by audio and interaction is controlled by a moderator managing turn-taking presentations. A use case execution proved a success and showed the potential of this immersive approach.

Electron cyclotron harmonic wave acceleration

NASA Technical Reports Server (NTRS)

Karimabadi, H.; Menyuk, C. R.; Sprangle, P.; Vlahos, L.

1987-01-01

A nonlinear analysis of particle acceleration in a finite bandwidth, obliquely propagating electromagnetic cyclotron wave is presented. It has been suggested by Sprangle and Vlahos in 1983 that the narrow bandwidth cyclotron radiation emitted by the unstable electron distribution inside a flaring solar loop can accelerate electrons outside the loop by the interaction of a monochromatic wave propagating along the ambient magnetic field with the ambient electrons. It is shown here that electrons gyrating and streaming along a uniform, static magnetic field can be accelerated by interacting with the fundamental or second harmonic of a monochromatic, obliquely propagating cyclotron wave. It is also shown that the acceleration is virtually unchanged when a wave with finite bandwidth is considered. This acceleration mechanism can explain the observed high-energy electrons in type III bursts.

Methods of Improving Speech Intelligibility for Listeners with Hearing Resolution Deficit

PubMed Central

2012-01-01

Abstract Methods developed for real-time time scale modification (TSM) of speech signal are presented. They are based on the non-uniform, speech rate depended SOLA algorithm (Synchronous Overlap and Add). Influence of the proposed method on the intelligibility of speech was investigated for two separate groups of listeners, i.e. hearing impaired children and elderly listeners. It was shown that for the speech with average rate equal to or higher than 6.48 vowels/s, all of the proposed methods have statistically significant impact on the improvement of speech intelligibility for hearing impaired children with reduced hearing resolution and one of the proposed methods significantly improves comprehension of speech in the group of elderly listeners with reduced hearing resolution. Virtual slides http://www.diagnosticpathology.diagnomx.eu/vs/2065486371761991 PMID:23009662

Derivatives of buckling loads and vibration frequencies with respect to stiffness and initial strain parameters

NASA Technical Reports Server (NTRS)

Haftka, Raphael T.; Cohen, Gerald A.; Mroz, Zenon

1990-01-01

A uniform variational approach to sensitivity analysis of vibration frequencies and bifurcation loads of nonlinear structures is developed. Two methods of calculating the sensitivities of bifurcation buckling loads and vibration frequencies of nonlinear structures, with respect to stiffness and initial strain parameters, are presented. A direct method requires calculation of derivatives of the prebuckling state with respect to these parameters. An adjoint method bypasses the need for these derivatives by using instead the strain field associated with the second-order postbuckling state. An operator notation is used and the derivation is based on the principle of virtual work. The derivative computations are easily implemented in structural analysis programs. This is demonstrated by examples using a general purpose, finite element program and a shell-of-revolution program.

Blueprint for antimicrobial hit discovery targeting metabolic networks

PubMed Central

Shen, Y.; Liu, J.; Estiu, G.; Isin, B.; Ahn, Y-Y.; Lee, D-S.; Barabási, A-L.; Kapatral, V.; Wiest, O.; Oltvai, Z. N.

2010-01-01

Advances in genome analysis, network biology, and computational chemistry have the potential to revolutionize drug discovery by combining system-level identification of drug targets with the atomistic modeling of small molecules capable of modulating their activity. To demonstrate the effectiveness of such a discovery pipeline, we deduced common antibiotic targets in Escherichia coli and Staphylococcus aureus by identifying shared tissue-specific or uniformly essential metabolic reactions in their metabolic networks. We then predicted through virtual screening dozens of potential inhibitors for several enzymes of these reactions and showed experimentally that a subset of these inhibited both enzyme activities in vitro and bacterial cell viability. This blueprint is applicable for any sequenced organism with high-quality metabolic reconstruction and suggests a general strategy for strain-specific antiinfective therapy. PMID:20080587

Application of external axis in thermal spraying

NASA Astrophysics Data System (ADS)

Gao, Guoyou; Wang, Wei; Chen, Tao; Hui, Chun

2018-05-01

Industrial robots are widely used nowadays in the process of thermal spraying, human work can be largely replaced due to the high-efficient, security, precision and repeatability of industrial robot. As offering the convenience to industrial product, Robots have some natural deficiencies because of its mechanical linkages of six-axis. When robot performs a series of stage of production, it could be hard to move to the next one because one of his axis reaches a maximum value. For this reason, external axis is added to robot system to extend the reachable space of robot axis. This paper concerns to the application of external axis and the different methods of programming the robot with work-holding external axis in the virtual environment. Experiments demonstrate the coating layer on the regular workpiece is uniform.

Space charge effects in ultrafast electron diffraction and imaging

NASA Astrophysics Data System (ADS)

Tao, Zhensheng; Zhang, He; Duxbury, P. M.; Berz, Martin; Ruan, Chong-Yu

2012-02-01

Understanding space charge effects is central for the development of high-brightness ultrafast electron diffraction and microscopy techniques for imaging material transformation with atomic scale detail at the fs to ps timescales. We present methods and results for direct ultrafast photoelectron beam characterization employing a shadow projection imaging technique to investigate the generation of ultrafast, non-uniform, intense photoelectron pulses in a dc photo-gun geometry. Combined with N-particle simulations and an analytical Gaussian model, we elucidate three essential space-charge-led features: the pulse lengthening following a power-law scaling, the broadening of the initial energy distribution, and the virtual cathode threshold. The impacts of these space charge effects on the performance of the next generation high-brightness ultrafast electron diffraction and imaging systems are evaluated.

National Kidney Registry: 213 transplants in three years.

PubMed

Veale, Jeffrey; Hil, Garet

2010-01-01

Since its establishment in 2008, the National Kidney Registry has facilitated 213 kidney transplants between unrelated living donors and recipients at 28 transplant centers. Rapid innovations in matching strategies, advanced computer technologies, good communication and an evolving understanding of the processes at participating transplant centers and histocompatibility laboratories are among the factors driving the success of the NKR. Virtual cross match accuracy has improved from 43% to 91% as a result of changes to the HLA typing requirements for potential donors and improved mechanisms to list unacceptable HLA antigens for sensitized patients. A uniform financial agreement among participating centers eliminated a major roadblock to facilitate unbalanced donor kidney exchanges among centers. The NKR transplanted 64% of the patients registered since 2008 and the average waiting time for those transplanted in 2010 was 11 months.

Uniformity on the grid via a configuration framework

DOE Office of Scientific and Technical Information (OSTI.GOV)

Igor V Terekhov et al.

2003-03-11

As Grid permeates modern computing, Grid solutions continue to emerge and take shape. The actual Grid development projects continue to provide higher-level services that evolve in functionality and operate with application-level concepts which are often specific to the virtual organizations that use them. Physically, however, grids are comprised of sites whose resources are diverse and seldom project readily onto a grid's set of concepts. In practice, this also creates problems for site administrators who actually instantiate grid services. In this paper, we present a flexible, uniform framework to configure a grid site and its facilities, and otherwise describe the resourcesmore » and services it offers. We start from a site configuration and instantiate services for resource advertisement, monitoring and data handling; we also apply our framework to hosting environment creation. We use our ideas in the Information Management part of the SAM-Grid project, a grid system which will deliver petabyte-scale data to the hundreds of users. Our users are High Energy Physics experimenters who are scattered worldwide across dozens of institutions and always use facilities that are shared with other experiments as well as other grids. Our implementation represents information in the XML format and includes tools written in XQuery and XSLT.« less

Modeling MultiCoil ICPs

NASA Astrophysics Data System (ADS)

Kolobov, V. I.; Vaidya, N.; Krishnan, A.

1998-10-01

Plasma processing of 300 mm wafers and flat panels places stringent demands on plasma uniformity across large surfaces. A natural solution towards an uniform plasma in a minimum discharge volume is to maintain the plasma by an array of individual sources. Although the design of the individual sources can differ considerably, there is a common feature for all such devices which have been recently suggested by several groups: their essentially 3D geometry. Engineering design of these devices is a challenging task and computational modeling could be a very useful tool. CFD Research Corp. has developed a comprehensive software for virtual prototyping of ICP sources designed for complex 3D geometries with unstructured solution-adaptive mesh. In this paper we shall present the results of our simulation of the multipole high density source [1] which is an example of MultiCoil ICP. We shall describe the procedure of solving the electromagnetic part of the problem using magnetic vector potential and analyse design issues such as the size of dielectric windows. We shall present results of parametric studies of the source for different geometries, gas pressures and plasma densities for simple argon chemistry. [1] J.Ogle. Proc. VI Int. Workshop on Advanced Plasma Tools and Process Engineering, pp. 85-90, May 1998, Millbrae, USA.

Use of Emerging Grid Computing Technologies for the Analysis of LIGO Data

NASA Astrophysics Data System (ADS)

Koranda, Scott

2004-03-01

The LIGO Scientific Collaboration (LSC) today faces the challenge of enabling analysis of terabytes of LIGO data by hundreds of scientists from institutions all around the world. To meet this challenge the LSC is developing tools, infrastructure, applications, and expertise leveraging Grid Computing technologies available today, and making available to LSC scientists compute resources at sites across the United States and Europe. We use digital credentials for strong and secure authentication and authorization to compute resources and data. Building on top of products from the Globus project for high-speed data transfer and information discovery we have created the Lightweight Data Replicator (LDR) to securely and robustly replicate data to resource sites. We have deployed at our computing sites the Virtual Data Toolkit (VDT) Server and Client packages, developed in collaboration with our partners in the GriPhyN and iVDGL projects, providing uniform access to distributed resources for users and their applications. Taken together these Grid Computing technologies and infrastructure have formed the LSC DataGrid--a coherent and uniform environment across two continents for the analysis of gravitational-wave detector data. Much work, however, remains in order to scale current analyses and recent lessons learned need to be integrated into the next generation of Grid middleware.

Using Virtualization to Integrate Weather, Climate, and Coastal Science Education

NASA Astrophysics Data System (ADS)

Davis, J. R.; Paramygin, V. A.; Figueiredo, R.; Sheng, Y.

2012-12-01

To better understand and communicate the important roles of weather and climate on the coastal environment, a unique publically available tool is being developed to support research, education, and outreach activities. This tool uses virtualization technologies to facilitate an interactive, hands-on environment in which students, researchers, and general public can perform their own numerical modeling experiments. While prior efforts have focused solely on the study of the coastal and estuary environments, this effort incorporates the community supported weather and climate model (WRF-ARW) into the Coastal Science Educational Virtual Appliance (CSEVA), an education tool used to assist in the learning of coastal transport processes; storm surge and inundation; and evacuation modeling. The Weather Research and Forecasting (WRF) Model is a next-generation, community developed and supported, mesoscale numerical weather prediction system designed to be used internationally for research, operations, and teaching. It includes two dynamical solvers (ARW - Advanced Research WRF and NMM - Nonhydrostatic Mesoscale Model) as well as a data assimilation system. WRF-ARW is the ARW dynamics solver combined with other components of the WRF system which was developed primarily at NCAR, community support provided by the Mesoscale and Microscale Meteorology (MMM) division of National Center for Atmospheric Research (NCAR). Included with WRF is the WRF Pre-processing System (WPS) which is a set of programs to prepare input for real-data simulations. The CSEVA is based on the Grid Appliance (GA) framework and is built using virtual machine (VM) and virtual networking technologies. Virtualization supports integration of an operating system, libraries (e.g. Fortran, C, Perl, NetCDF, etc. necessary to build WRF), web server, numerical models/grids/inputs, pre-/post-processing tools (e.g. WPS / RIP4 or UPS), graphical user interfaces, "Cloud"-computing infrastructure and other tools into a single ready-to-use package. Thus, the previous ornery task of setting up and compiling these tools becomes obsolete and the research, educator or student can focus on using the tools to study the interactions between weather, climate and the coastal environment. The incorporation of WRF into the CSEVA has been designed to be synergistic with the extensive online tutorials and biannual tutorials hosted by NCAR. Included are working examples of the idealized test simulations provided with WRF (2D sea breeze and squalls, a large eddy simulation, a Held and Suarez simulation, etc.) To demonstrate the integration of weather, coastal and coastal science education, example applications are being developed to demonstrate how the system can be used to couple a coastal and estuarine circulation, transport and storm surge model with downscale reanalysis weather and future climate predictions. Documentation, tutorials and the enhanced CSEVA itself will be found on the web at: http://cseva.coastal.ufl.edu.

Build and Execute Environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guan, Qiang

At exascale, the challenge becomes to develop applications that run at scale and use exascale platforms reliably, efficiently, and flexibly. Workflows become much more complex because they must seamlessly integrate simulation and data analytics. They must include down-sampling, post-processing, feature extraction, and visualization. Power and data transfer limitations require these analysis tasks to be run in-situ or in-transit. We expect successful workflows will comprise multiple linked simulations along with tens of analysis routines. Users will have limited development time at scale and, therefore, must have rich tools to develop, debug, test, and deploy applications. At this scale, successful workflows willmore » compose linked computations from an assortment of reliable, well-defined computation elements, ones that can come and go as required, based on the needs of the workflow over time. We propose a novel framework that utilizes both virtual machines (VMs) and software containers to create a workflow system that establishes a uniform build and execution environment (BEE) beyond the capabilities of current systems. In this environment, applications will run reliably and repeatably across heterogeneous hardware and software. Containers, both commercial (Docker and Rocket) and open-source (LXC and LXD), define a runtime that isolates all software dependencies from the machine operating system. Workflows may contain multiple containers that run different operating systems, different software, and even different versions of the same software. We will run containers in open-source virtual machines (KVM) and emulators (QEMU) so that workflows run on any machine entirely in user-space. On this platform of containers and virtual machines, we will deliver workflow software that provides services, including repeatable execution, provenance, checkpointing, and future proofing. We will capture provenance about how containers were launched and how they interact to annotate workflows for repeatable and partial re-execution. We will coordinate the physical snapshots of virtual machines with parallel programming constructs, such as barriers, to automate checkpoint and restart. We will also integrate with HPC-specific container runtimes to gain access to accelerators and other specialized hardware to preserve native performance. Containers will link development to continuous integration. When application developers check code in, it will automatically be tested on a suite of different software and hardware architectures.« less

Improving Scientific Research for the GEO Geohazard Supersites through a Virtual Research Environment

NASA Astrophysics Data System (ADS)

Salvi, S.; Trasatti, E.; Rubbia, G.; Romaniello, V.; Spinetti, C.; Corradini, S.; Merucci, L.

2016-12-01

The EU's H2020 EVER-EST Project is dedicated to the realization of a Virtual Research Environment (VRE) for Earth Science researchers, during 2015-2018. EVER-EST implements state-of-the-art technologies in the area of Earth Science data catalogues, data access/processing and long-term data preservation together with models, techniques and tools for the computational methods, such as scientific workflows. The VRE is designed with the aim of providing the Earth Science user community with an innovative virtual environment to enhance their ability to interoperate and share knowledge and experience, exploiting also the Research Object concept. The GEO Geohazard Supersites is one of the four Research Communities chosen to validate the e-infrastructure. EVER-EST will help the exploitation of the full potential of the GEO Geohazard Supersite and Natural Laboratories (GSNL) initiative demonstrating the use case in the Permanent Supersites of Mt Etna, Campi Flegrei-Vesuvius, and Icelandic volcanoes. Besides providing tools for active volcanoes monitoring and studies, we intend to demonstrate how a more organized and collaborative research environment, such as a VRE, can improve the quality of the scientific research on the Geohazard Supersites, addressing at the same time the problem of the slow uptake of scientific research findings in Disaster Risk Management. Presently, the full exploitation of the in situ and satellite data made available for each Supersite is delayed by the difficult access (especially for researchers in developing countries) to intensive processing and modeling capabilities. EVER-EST is designed to provide these means and also a friendly virtual environment for the easy transfer of scientific knowledge as soon as it is acquired, promoting collaboration among researchers located in distant regions of the world. A further benefit will be to increase the societal impact of the scientific advancements obtained in the Supersites, allowing a more uniform interface towards the different user communities, who will use part of the services provided by EVER-EST during research result uptake. We show a few test cases of use of the Geohazard Supersite VRE at the actual state of development, and its future development.

Nonlinear Buckling Analysis of Functionally Graded Graphene Reinforced Composite Shallow Arches with Elastic Rotational Constraints under Uniform Radial Load.

PubMed

Huang, Yonghui; Yang, Zhicheng; Liu, Airong; Fu, Jiyang

2018-05-28

The buckling behavior of functionally graded graphene platelet-reinforced composite (FG-GPLRC) shallow arches with elastic rotational constraints under uniform radial load is investigated in this paper. The nonlinear equilibrium equation of the FG-GPLRC shallow arch with elastic rotational constraints under uniform radial load is established using the Halpin-Tsai micromechanics model and the principle of virtual work, from which the critical buckling load of FG-GPLRC shallow arches with elastic rotational constraints can be obtained. This paper gives special attention to the effect of the GPL distribution pattern, weight fraction, geometric parameters, and the constraint stiffness on the buckling load. The numerical results show that all of the FG-GPLRC shallow arches with elastic rotational constraints have a higher buckling load-carrying capacity compared to the pure epoxy arch, and arches of the distribution pattern X have the highest buckling load among four distribution patterns. When the GPL weight fraction is constant, the thinner and larger GPL can provide the better reinforcing effect to the FG-GPLRC shallow arch. However, when the value of the aspect ratio is greater than 4, the flakiness ratio is greater than 103, and the effect of GPL's dimensions on the buckling load of the FG-GPLRC shallow arch is less significant. In addition, the buckling model of FG-GPLRC shallow arch with elastic rotational constraints is changed as the GPL distribution patterns or the constraint stiffness changes. It is expected that the method and the results that are presented in this paper will be useful as a reference for the stability design of this type of arch in the future.

An adaptive mesh refinement-multiphase lattice Boltzmann flux solver for simulation of complex binary fluid flows

NASA Astrophysics Data System (ADS)

Yuan, H. Z.; Wang, Y.; Shu, C.

2017-12-01

This paper presents an adaptive mesh refinement-multiphase lattice Boltzmann flux solver (AMR-MLBFS) for effective simulation of complex binary fluid flows at large density ratios. In this method, an AMR algorithm is proposed by introducing a simple indicator on the root block for grid refinement and two possible statuses for each block. Unlike available block-structured AMR methods, which refine their mesh by spawning or removing four child blocks simultaneously, the present method is able to refine its mesh locally by spawning or removing one to four child blocks independently when the refinement indicator is triggered. As a result, the AMR mesh used in this work can be more focused on the flow region near the phase interface and its size is further reduced. In each block of mesh, the recently proposed MLBFS is applied for the solution of the flow field and the level-set method is used for capturing the fluid interface. As compared with existing AMR-lattice Boltzmann models, the present method avoids both spatial and temporal interpolations of density distribution functions so that converged solutions on different AMR meshes and uniform grids can be obtained. The proposed method has been successfully validated by simulating a static bubble immersed in another fluid, a falling droplet, instabilities of two-layered fluids, a bubble rising in a box, and a droplet splashing on a thin film with large density ratios and high Reynolds numbers. Good agreement with the theoretical solution, the uniform-grid result, and/or the published data has been achieved. Numerical results also show its effectiveness in saving computational time and virtual memory as compared with computations on uniform meshes.

Comparative analysis of human ex vivo–generated platelets vs megakaryocyte-generated platelets in mice: a cautionary tale

PubMed Central

Wang, Yuhuan; Hayes, Vincent; Jarocha, Danuta; Sim, Xiuli; Harper, Dawn C.; Fuentes, Rudy; Sullivan, Spencer K.; Gadue, Paul; Chou, Stella T.; Torok-Storb, Beverly J.; Marks, Michael S.; French, Deborah L.

2015-01-01

Thrombopoiesis is the process by which megakaryocytes release platelets that circulate as uniform small, disc-shaped anucleate cytoplasmic fragments with critical roles in hemostasis and related biology. The exact mechanism of thrombopoiesis and the maturation pathways of platelets released into the circulation remain incompletely understood. We showed that ex vivo–generated murine megakaryocytes infused into mice release platelets within the pulmonary vasculature. Here we now show that infused human megakaryocytes also release platelets within the lungs of recipient mice. In addition, we observed a population of platelet-like particles (PLPs) in the infusate, which include platelets released during ex vivo growth conditions. By comparing these 2 platelet populations to human donor platelets, we found marked differences: platelets derived from infused megakaryocytes closely resembled infused donor platelets in morphology, size, and function. On the other hand, the PLP was a mixture of nonplatelet cellular fragments and nonuniform-sized, preactivated platelets mostly lacking surface CD42b that were rapidly cleared by macrophages. These data raise a cautionary note for the clinical use of human platelets released under standard ex vivo conditions. In contrast, human platelets released by intrapulmonary-entrapped megakaryocytes appear more physiologic in nature and nearly comparable to donor platelets for clinical application. PMID:25852052

Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression

NASA Astrophysics Data System (ADS)

Varshnay, N. K.; Singh, A.; Benerji, N. S.

2017-02-01

Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression suitable for material processing applications are presented here. The laser incorporates in-built compact gas circulation and gas cooling to ensure fresh gas mixture between the electrodes for repetitive operation. A magnetically coupled tangential blower is used for gas circulation inside the laser chamber for repetitive operation. The exciter consists of C-C energy transfer circuit and thyratron is used as a high-voltage main switch with single-stage magnetic pulse compression (MPC) between thyratron and the laser electrodes. Low inductance of the laser head and uniform and intense pre-ionization are the main features of the electric circuit used in the laser. A 250 ns rise time voltage pulse was compressed to 100 ns duration with a single-stage magnetic pulse compressor using Ni-Zn ferrite cores. The laser can generate about 150 mJ at ˜100 Hz rep-rate reliably from a discharge volume of 100 cm 3. 2D spatial laser beam profile generated is presented here. The profile shows that the laser beam is completely filled with flat-top which is suitable for material processing applications. The SEM image of the microhole generated on copper target is presented here.

The hydrodynamic and ultrasound-induced forces on microbubbles under high Reynolds number flow representative of the human systemic circulation

NASA Astrophysics Data System (ADS)

Clark, Alicia; Aliseda, Alberto

2016-11-01

Ultrasound contrast agents (UCAs) are micron-sized bubbles that are used in conjunction with ultrasound (US) in medical applications such as thrombolysis and targeted intravenous drug delivery. Previous work has shown that the Bjerknes force, due to the phase difference between the incoming US pressure wave and the bubble volume oscillations, can be used to manipulate the trajectories of microbubbles. Our work explores the behavior of microbubbles in medium sized blood vessels under both uniform and pulsatile flows at a range of physiologically relevant Reynolds and Womersley numbers. High speed images were taken of the microbubbles in an in-vitro flow loop that replicates physiological flow conditions. During the imaging, the microbubbles were insonified at different diagnostic ultrasound settings (varying center frequency, PRF, etc.). An in-house Lagrangian particle tracking code was then used to determine the trajectories of the microbubbles and, thus, a dynamic model for the microbubbles including the Bjerknes forces acting on them, as well as drag, lift, and added mass. Preliminary work has also explored the behavior of the microbubbles in a patient-specific model of a carotid artery bifurcation to demonstrate the feasibility of preferential steering of microbubbles towards the intracranial circulation with US.

Evidence linking rapid Arctic warming to mid-latitude weather patterns.

PubMed

Francis, Jennifer; Skific, Natasa

2015-07-13

The effects of rapid Arctic warming and ice loss on weather patterns in the Northern Hemisphere is a topic of active research, lively scientific debate and high societal impact. The emergence of Arctic amplification--the enhanced sensitivity of high-latitude temperature to global warming--in only the last 10-20 years presents a challenge to identifying statistically robust atmospheric responses using observations. Several recent studies have proposed and demonstrated new mechanisms by which the changing Arctic may be affecting weather patterns in mid-latitudes, and these linkages differ fundamentally from tropics/jet-stream interactions through the transfer of wave energy. In this study, new metrics and evidence are presented that suggest disproportionate Arctic warming-and resulting weakening of the poleward temperature gradient-is causing the Northern Hemisphere circulation to assume a more meridional character (i.e. wavier), although not uniformly in space or by season, and that highly amplified jet-stream patterns are occurring more frequently. Further analysis based on self-organizing maps supports this finding. These changes in circulation are expected to lead to persistent weather patterns that are known to cause extreme weather events. As emissions of greenhouse gases continue unabated, therefore, the continued amplification of Arctic warming should favour an increased occurrence of extreme events caused by prolonged weather conditions.

Non-hydrostatic general circulation model of the Venus atmosphere

NASA Astrophysics Data System (ADS)

Rodin, Alexander V.; Mingalev, Igor; Orlov, Konstantin; Ignatiev, Nikolay

We present the first non-hydrostatic global circulation model of the Venus atmosphere based on the complete set of gas dynamics equations. The model employs a spatially uniform triangular mesh that allows to avoid artificial damping of the dynamical processes in the polar regions, with altitude as a vertical coordinate. Energy conversion from the solar flux into atmospheric motion is described via explicitly specified heating and cooling rates or, alternatively, with help of the radiation block based on comprehensive treatment of the Venus atmosphere spectroscopy, including line mixing effects in CO2 far wing absorption. Momentum equations are integrated using the semi-Lagrangian explicit scheme that provides high accuracy of mass and energy conservation. Due to high vertical grid resolution required by gas dynamics calculations, the model is integrated on the short time step less than one second. The model reliably repro-duces zonal superrotation, smoothly extending far below the cloud layer, tidal patterns at the cloud level and above, and non-rotating, sun-synchronous global convective cell in the upper atmosphere. One of the most interesting features of the model is the development of the polar vortices resembling those observed by Venus Express' VIRTIS instrument. Initial analysis of the simulation results confirms the hypothesis that it is thermal tides that provides main driver for the superrotation.

The Quaternary and Pliocene Yellowstone Plateau volcanic field of Wyoming, Idaho, and Montana

USGS Publications Warehouse

Christiansen, Robert L.

2001-01-01

This region of Yellowstone National Park has been the active focus of one of the Earth's largest magmatic systems for more than 2 million years. The resulting volcanism has been characterized by the eruption of voluminous rhyolites and subordinate basalts but virtually no lavas of intermediate composition. The magmatic system at depth remains active and drives the massive hydrothermal circulation for which the park is widely known. Studies of the volcanic field using geologic mapping and petrology have defined three major cycles of rhyolitic volcanism, each climaxed by the eruption of a rhyolitic ash-flow sheet having a volume of hundreds of thousands of cubic kilometers. The field also has been analyzed in terms of its magmatic and tectonic evolution, including its regional relation to the Snake River plain and to basin-range tectonic extension.

MO-F-CAMPUS-T-04: Utilization of Optical Dosimeter for Modulated Spot-Scanning Particle Beam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsi, W; Li, Y; Huang, Z

Purpose: To present the utilization of an optical dosimeter for modulated spot-scanning carbon-ion and proton beams during the acceptance test of Siemens IONTRIS system. Method and Materials: An optical dosimeter using phosphor scintillation was developed to map and interactively analyze the shapes and sizes of spots over 190 energies for ProTom modulated-scanning system. The dose response to proton had been characterized with proper pixel calibration at ProTom system. The dose response was further studied at 0.7 cm depths by uniform 8cm in-diameter fields of 424.89 MeV/u (E290) carbon-ions and 215.18MeV (E282) protons at IONTRIS system. The virtual source axial distancesmore » (vSAD) of carbonions and protons of IONTRIS system was investigated by measuring either variations of spot position or field size at five different locations to Isocenter. By measuring lateral profiles of uniform doses with varied thin-thicknesses of chest-board pattern and placing the scintillation plate at near to the distal edge, range variations at different off-axis-distances (rOAD) were examined. Relative accuracy and reproducibility of beam range were measured for three beam ranges with a ramping block at front of scintillation plate. Results: Similar dose response was observed for high energies of carbon ions and protons. Mean vSAD at X and Y axes were 744.1 cm and 807.4cm with deviation of 7.4cm and 7.7cm, respectively. Variation of rOAD was within 0.35 mm over 10cm for both protons and carbon ions. Accuracy of measuring relative distal range using the ramping block was 0.2mm. Measured range over repeated three times for each range were within 0.25mm at same room, and within 1.0mm between four rooms. Conclusions: The optical dosimeter could efficiently measure the virtual source distance. And, to measure small range variation at different off-axial locations, and for the relative beam range between rooms during acceptance test of a modulated spot-scanning particle system.« less

Segmentation of vessels cluttered with cells using a physics based model.

PubMed

Schmugge, Stephen J; Keller, Steve; Nguyen, Nhat; Souvenir, Richard; Huynh, Toan; Clemens, Mark; Shin, Min C

2008-01-01

Segmentation of vessels in biomedical images is important as it can provide insight into analysis of vascular morphology, topology and is required for kinetic analysis of flow velocity and vessel permeability. Intravital microscopy is a powerful tool as it enables in vivo imaging of both vasculature and circulating cells. However, the analysis of vasculature in those images is difficult due to the presence of cells and their image gradient. In this paper, we provide a novel method of segmenting vessels with a high level of cell related clutter. A set of virtual point pairs ("vessel probes") are moved reacting to forces including Vessel Vector Flow (VVF) and Vessel Boundary Vector Flow (VBVF) forces. Incorporating the cell detection, the VVF force attracts the probes toward the vessel, while the VBVF force attracts the virtual points of the probes to localize the vessel boundary without being distracted by the image features of the cells. The vessel probes are moved according to Newtonian Physics reacting to the net of forces applied on them. We demonstrate the results on a set of five real in vivo images of liver vasculature cluttered by white blood cells. When compared against the ground truth prepared by the technician, the Root Mean Squared Error (RMSE) of segmentation with VVF and VBVF was 55% lower than the method without VVF and VBVF.

Laparoscopic simulation training in gynaecology: Current provision and staff attitudes - a cross-sectional survey.

PubMed

Burden, Christy; Fox, Robert; Hinshaw, Kim; Draycott, Timothy J; James, Mark

2016-01-01

The objectives of this study were to explore current provision of laparoscopic simulation training, and to determine attitudes of trainers and trainees to the role of simulators in surgical training across the UK. An anonymous cross-sectional survey with cluster sampling was developed and circulated. All Royal College of Obstetricians and Gynaecologists (RCOG) Training Programme Directors (TPD), College Tutors (RCT) and Trainee representatives (TR) across the UK were invited to participate. One hundred and ninety-six obstetricians and gynaecologists participated. Sixty-three percent of hospitals had at least one box trainer, and 14.6% had least one virtual-reality simulator. Only 9.3% and 3.6% stated that trainees used a structured curriculum on box and virtual-reality simulators, respectively. Respondents working in a Large/Teaching hospital (p = 0.008) were more likely to agree that simulators enhance surgical training. Eighty-nine percent agreed that simulators improve the quality of training, and should be mandatory or desirable for junior trainees. Consultants (p = 0.003) and respondents over 40 years (p = 0.011) were more likely to hold that a simulation test should be undertaken before live operation. Our data demonstrated, therefore, that availability of laparoscopic simulators is inconsistent, with limited use of mandatory structured curricula. In contrast, both trainers and trainees recognise a need for greater use of laparoscopic simulation for surgical training.

Patient-specific biomechanical model of hypoplastic left heart to predict post-operative cardio-circulatory behaviour.

PubMed

Cutrì, Elena; Meoli, Alessio; Dubini, Gabriele; Migliavacca, Francesco; Hsia, Tain-Yen; Pennati, Giancarlo

2017-09-01

Hypoplastic left heart syndrome is a complex congenital heart disease characterised by the underdevelopment of the left ventricle normally treated with a three-stage surgical repair. In this study, a multiscale closed-loop cardio-circulatory model is created to reproduce the pre-operative condition of a patient suffering from such pathology and virtual surgery is performed. Firstly, cardio-circulatory parameters are estimated using a fully closed-loop cardio-circulatory lumped parameter model. Secondly, a 3D standalone FEA model is build up to obtain active and passive ventricular characteristics and unloaded reference state. Lastly, the 3D model of the single ventricle is coupled to the lumped parameter model of the circulation obtaining a multiscale closed-loop pre-operative model. Lacking any information on the fibre orientation, two cases were simulated: (i) fibre distributed as in the physiological right ventricle and (ii) fibre as in the physiological left ventricle. Once the pre-operative condition is satisfactorily simulated for the two cases, virtual surgery is performed. The post-operative results in the two cases highlighted similar hemodynamic behaviour but different local mechanics. This finding suggests that the knowledge of the patient-specific fibre arrangement is important to correctly estimate the single ventricle's working condition and consequently can be valuable to support clinical decision. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Internal flow inside droplets within a concentrated emulsion during droplet rearrangement

NASA Astrophysics Data System (ADS)

Leong, Chia Min; Gai, Ya; Tang, Sindy K. Y.

2018-03-01

Droplet microfluidics, in which each droplet serves as a micro-reactor, has found widespread use in high-throughput biochemical screening applications. These droplets are often concentrated at various steps to form a concentrated emulsion. As part of a serial interrogation and sorting process, such concentrated emulsions are typically injected into a tapered channel leading to a constriction that fits one drop at a time for the probing of droplet content in a serial manner. The flow physics inside the droplets under these flow conditions are not well understood but are critical for predicting and controlling the mixing of reagents inside the droplets as reactors. Here we investigate the flow field inside droplets of a concentrated emulsion flowing through a tapered microchannel using micro-particle image velocimetry. The confining geometry of the channel forces the number of rows of drops to reduce by one at specific and uniformly spaced streamwise locations, which are referred to as droplet rearrangement zones. Within each rearrangement zone, the phase-averaged velocity results show that the motion of the droplets involved in the rearrangement process, also known as a T1 event, creates vortical structures inside themselves and their adjacent droplets. These flow structures increase the circulation inside droplets up to 2.5 times the circulation in droplets at the constriction. The structures weaken outside of the rearrangement zones suggesting that the flow patterns created by the T1 process are transient. The time scale of circulation is approximately the same as the time scale of a T1 event. Outside of the rearrangement zones, flow patterns in the droplets are determined by the relative velocity between the continuous and disperse phases.

Diurnal Cycle of Surface Flows During NAME and Comparison to Model Reanalysis

NASA Astrophysics Data System (ADS)

Ciesielski, P. E.; Johnson, R. H.

2007-05-01

During the North American Monsoon Experiment (NAME) an unprecedented surface data set of winds and thermodynamic variables was collected over the core monsoon region. The surface network included 63 automated sites with 1-30 min resolution data, 27 SMN operational sites (1-3 hourly data), and 56 US operational sites (1-3 hourly data) along the northern fringe of the monsoon region. These data, along with twice daily QuikSCAT oceanic surface winds, were quality controlled and objectively analyzed on to a uniform grid with quarter-degree, 1-h resolution for the period from 1 July - 15 August. An important application of the gridded winds is their use in diagnosing surface vertical motion due to slope flows over the Sierra Madre Occidental (SMO) terrain. With this dataset we examine the diurnal characteristics of surface fields as the monsoon evolves and compare these analyses to similar surface products from the special North American Regional Reanalysis (NARR) for NAME. Observed surface fields indicate that a robust land-sea breeze circulation is present over most of Gulf of California (GOC) region in response to the strong diurnal heating of land masses on both sides of the gulf. For reasons unclear at this time, many features of this land-sea breeze circulation are missing in the NARR. Evolution of the diurnal cycle of temperature and the land- sea breeze circulation as the monsoon progresses through the season shows a strong sensitivity to rainfall over the SMO and the coastal plains. Such a relationship likely reflects changes in land surface characteristics, such as evapotranspiration and albedo, as the forests of the SMO respond to monsoonal rains.

A chip assisted immunomagnetic separation system for the efficient capture and in situ identification of circulating tumor cells.

PubMed

Tang, Man; Wen, Cong-Ying; Wu, Ling-Ling; Hong, Shao-Li; Hu, Jiao; Xu, Chun-Miao; Pang, Dai-Wen; Zhang, Zhi-Ling

2016-04-07

The detection of circulating tumor cells (CTCs), a kind of "liquid biopsy", represents a potential alternative to noninvasive detection, characterization and monitoring of carcinoma. Many previous studies have shown that the number of CTCs has a significant relationship with the stage of cancer. However, CTC enrichment and detection remain notoriously difficult because they are extremely rare in the bloodstream. Herein, aided by a microfluidic device, an immunomagnetic separation system was applied to efficiently capture and in situ identify circulating tumor cells. Magnetic nanospheres (MNs) were modified with an anti-epithelial-cell-adhesion-molecule (anti-EpCAM) antibody to fabricate immunomagnetic nanospheres (IMNs). IMNs were then loaded into the magnetic field controllable microfluidic chip to form uniform IMN patterns. The IMN patterns maintained good stability during the whole processes including enrichment, washing and identification. Apart from its simple manufacture process, the obtained microfluidic device was capable of capturing CTCs from the bloodstream with an efficiency higher than 94%. The captured cells could be directly visualized with an inverted fluorescence microscope in situ by immunocytochemistry (ICC) identification, which decreased cell loss effectively. Besides that, the CTCs could be recovered completely just by PBS washing after removal of the permanent magnets. It was observed that all the processes showed negligible influence on cell viability (viability up to 93%) and that the captured cells could be re-cultured for more than 5 passages after release without disassociating IMNs. In addition, the device was applied to clinical samples and almost all the samples from patients showed positive results, which suggests it could serve as a valuable tool for CTC enrichment and detection in the clinic.

How much rainfall sustained a Green Sahara during the mid-Holocene?

NASA Astrophysics Data System (ADS)

Hopcroft, Peter; Valdes, Paul; Harper, Anna

2016-04-01

The present-day Sahara desert has periodically transformed to an area of lakes and vegetation during the Quaternary in response to orbitally-induced changes in the monsoon circulation. Coupled atmosphere-ocean general circulation model simulations of the mid-Holocene generally underestimate the required monsoon shift, casting doubt on the fidelity of these models. However, the climatic regime that characterised this period remains unclear. To address this, we applied an ensemble of dynamic vegetation model simulations using two different models: JULES (Joint UK Land Environment Simulator) a comprehensive land surface model, and LPJ (Lund-Potsdam-Jena model) a widely used dynamic vegetation model. The simulations are forced with a number of idealized climate scenarios, in which an observational climatology is progressively altered with imposed anomalies of precipitation and other related variables, including cloud cover and humidity. The applied anomalies are based on an ensemble of general circulation model simulations, and include seasonal variations but are spatially uniform across the region. When perturbing precipitation alone, a significant increase of at least 700mm/year is required to produce model simulations with non-negligible vegetation coverage in the Sahara region. Changes in related variables including cloud cover, surface radiation fluxes and humidity are found to be important in the models, as they modify the water balance and so affect plant growth. Including anomalies in all of these variables together reduces the precipitation change required for a Green Sahara compared to the case of increasing precipitation alone. We assess whether the precipitation changes implied by these vegetation model simulations are consistent with reconstructions for the mid-Holocene from pollen samples. Further, Earth System models predict precipitation increases that are significantly smaller than that inferred from these vegetation model simulations. Understanding this difference presents an ongoing challenge.

Results on Jupiter's Atmosphere from the Juno Microwave Radiometer

NASA Astrophysics Data System (ADS)

Janssen, M. A.; Bolton, S. J.; Levin, S.; Adumitroaie, V.; Allison, M. D.; Arballo, J. K.; Atreya, S. K.; Bellotti, A.; Brown, S. T.; Gulkis, S.; Ingersoll, A. P.; Li, C.; Li, L.; Lunine, J. I.; Misra, S.; Orton, G. S.; Oyafuso, F. A.; Santos-Costa, D.; Sarkissian, E.; Steffes, P. G.; Zhang, Z.

2017-12-01

The Juno Microwave Radiometer (MWR) was designed to investigate Jupiter's atmosphere and radiation belts as one of a suite of instruments on the Juno mission. The MWR's main objective is to investigate the composition and dynamics of Jupiter's neutral atmosphere. Juno has now completed eight perijove passes that sample the atmosphere approximately every 45° in longitude, and the MWR has completed its main collection of data pertaining to the composition and structure of Jupiter's atmosphere. The primary results for atmospheric structure elaborate on the original discovery that the concentration of ammonia is far from uniformly mixed beneath its saturation level in the atmosphere and that deep atmospheric circulations control its distribution. Conversely, features of the deep circulation may be inferred from this distribution. Distinct circulation patterns are seen for three latitudinal regions: 1) Equatorial, where a column of increased ammonia concentration associated with the equatorial zone is sandwiched by off-equatorial regions of depleted ammonia in the north and south equatorial belts, with structure apparent to approximately the 100-bar pressure level, 2) Midlatitudes, where a stratified ammonia concentration appears stable, and 3) Polar, dominated by deep vertical structures associated with the observed surface vortices. Longitudinal structure is seen in the equatorial region primarily above the level of the water cloud around the 8-bar level, while significant structure appears small or absent outside and below this region. The ability of the MWR to detect lightning at its longest wavelengths was unexpected but sheds light on the presence of water and the distribution of strong convective regions in the atmosphere. The implications of these results for atmospheric dynamics and composition will be discussed.

Microgravity acoustic mixing for particle cloud combustors

NASA Technical Reports Server (NTRS)

Pla, Frederic; Rubinstein, Robert I.

1990-01-01

Experimental and theoretical investigations of acoustic mixing procedures designed to uniformly distribute fuel particles in a combustion tube for application in the proposed Particle Cloud Combustion Experiment (PCCE) are described. Two acoustic mixing methods are investigated: mixing in a cylindrical tube using high frequency spinning modes generated by suitably phased, or quadrature speakers, and acoustic premixing in a sphere. Quadrature mixing leads to rapid circumferential circulation of the powder around the tube. Good mixing is observed in the circulating regions. However, because axial inhomogeneities are necessarily present in the acoustic field, this circulation does not extend throughout the tube. Simultaneous operation of the quadrature-speaker set and the axial-speaker was observed to produce considerably enhanced mixing compared to operation of the quadrature-speaker set alone. Mixing experiments using both types of speakers were free of the longitudinal powder drift observed using axial-speakers alone. Vigorous powder mixing was obtained in the sphere for many normal modes: however, in no case was the powder observed to fill the sphere entirely. Theoretical analysis indicated that mixing under steady conditions cannot fill more than a hemisphere except under very unusual conditions. Premixing in a hemisphere may be satisfactory; otherwise, complete mixing in microgravity might be possible by operating the speaker in short bursts. A general conclusion is that acoustic transients are more likely to produce good mixing than steady state conditions. The reason is that in steady conditions, flow structures like nodal planes are possible and often even unavoidable. These tend to separate the mixing region into cells across which powder cannot be transferred. In contrast, transients not only are free of such structures, they also have the characteristics, desirable for mixing, of randomness and disorder. This conclusion is corroborated by mixing experiments using axial waves.

Dissolution-induced preferential flow in a limestone fracture.

PubMed

Liu, Jishan; Polak, Amir; Elsworth, Derek; Grader, Avrami

2005-06-01

Flow in a rock fracture is surprisingly sensitive to the evolution of flow paths that develop as a result of dissolution. Net dissolution may either increase or decrease permeability uniformly within the fracture, or may form a preferential flow path through which most of the injected fluid flows, depending on the prevailing ambient mechanical and chemical conditions. A flow-through test was completed on an artificial fracture in limestone at room temperature under ambient confining stress of 3.5 MPa. The sample was sequentially circulated by water of two different compositions through the 1500 h duration of the experiment; the first 935 h by tap groundwater, followed by 555 h of distilled water. Measurements of differential pressures between the inlet and the outlet, fluid and dissolved mass fluxes, and concurrent X-ray CT imaging and sectioning were used to characterize the evolution of flow paths within the limestone fracture. During the initial circulation of groundwater, the differential pressure increased almost threefold, and was interpreted as a net reduction in permeability as the contacting asperities across the fracture are removed, and the fracture closes. With the circulation of distilled water, permeability initially reduces threefold, and ultimately increases by two orders of magnitude. This spontaneous switch from net decrease in permeability, to net increase occurred with no change in flow rate or applied effective stress, and is attributed to the evolving localization of flow path as evidenced by CT images. Based on the X-ray CT characterizations, a flow path-dependent flow model was developed to simulate the evolution of flow paths within the fracture and its influence on the overall flow behaviors of the injected fluid in the fracture.

Single and Double ITCZ in Aqua-Planet Models with Globally and Temporally Uniform Sea Surface Temperature and Solar Insolation: An Interpretation

NASA Technical Reports Server (NTRS)

Chao, Winston C.; Chen, Baode; Lau, William K. M. (Technical Monitor)

2002-01-01

Previous studies (Chao 2000, Chao and Chen 2001, Kirtman and Schneider 2000, Sumi 1992) have shown that, by means of one of several model design changes, the structure of the ITCZ in an aqua-planet model with globally uniform SST and solar angle (U-SST-SA) can change between a single ITCZ at the equator and a double ITCZ straddling the equator. These model design changes include switching to a different cumulus parameterization scheme (e.g., from relaxed Arakawa Schubert scheme (RAS) to moist convective adjustment scheme (MCA)), changes within the cumulus parameterization scheme, and changes in other aspects of the model, such as horizontal resolution. Sometimes only one component of the double ITCZ shows up; but still this is an ITCZ away from the equator, quite distinct from a single ITCZ over the equator. Since these model results were obtained by different investigators using different models which have yielded reasonable general circulation, they are considered as reliable. Chao and Chen (2001; hereafter CC01) have made an initial attempt to interpret these findings based on the concept of rotational ITCZ attractors that they introduced. The purpose of this paper is to offer a more complete interpretation.

Regional paleofire regimes affected by non-uniform climate, vegetation and human drivers

NASA Astrophysics Data System (ADS)

Blarquez, Olivier; Ali, Adam A.; Girardin, Martin P.; Grondin, Pierre; Fréchette, Bianca; Bergeron, Yves; Hély, Christelle

2015-09-01

Climate, vegetation and humans act on biomass burning at different spatial and temporal scales. In this study, we used a dense network of sedimentary charcoal records from eastern Canada to reconstruct regional biomass burning history over the last 7000 years at the scale of four potential vegetation types: open coniferous forest/tundra, boreal coniferous forest, boreal mixedwood forest and temperate forest. The biomass burning trajectories were compared with regional climate trends reconstructed from general circulation models, tree biomass reconstructed from pollen series, and human population densities. We found that non-uniform climate, vegetation and human drivers acted on regional biomass burning history. In the open coniferous forest/tundra and dense coniferous forest, the regional biomass burning was primarily shaped by gradual establishment of less climate-conducive burning conditions over 5000 years. In the mixed boreal forest an increasing relative proportion of flammable conifers in landscapes since 2000 BP contributed to maintaining biomass burning constant despite climatic conditions less favourable to fires. In the temperate forest, biomass burning was uncoupled with climatic conditions and the main driver was seemingly vegetation until European colonization, i.e. 300 BP. Tree biomass and thus fuel accumulation modulated fire activity, an indication that biomass burning is fuel-dependent and notably upon long-term co-dominance shifts between conifers and broadleaf trees.

Nonisothermal Brownian motion: Thermophoresis as the macroscopic manifestation of thermally biased molecular motion.

PubMed

Brenner, Howard

2005-12-01

A quiescent single-component gravity-free gas subject to a small steady uniform temperature gradient T, despite being at rest, is shown to experience a drift velocity UD=-D* gradient ln T, where D* is the gas's nonisothermal self-diffusion coefficient. D* is identified as being the gas's thermometric diffusivity alpha. The latter differs from the gas's isothermal isotopic self-diffusion coefficient D, albeit only slightly. Two independent derivations are given of this drift velocity formula, one kinematical and the other dynamical, both derivations being strictly macroscopic in nature. Within modest experimental and theoretical uncertainties, this virtual drift velocity UD=-alpha gradient ln T is shown to be constitutively and phenomenologically indistinguishable from the well-known experimental and theoretical formulas for the thermophoretic velocity U of a macroscopic (i.e., non-Brownian) non-heat-conducting particle moving under the influence of a uniform temperature gradient through an otherwise quiescent single-component rarefied gas continuum at small Knudsen numbers. Coupled with the size independence of the particle's thermophoretic velocity, the empirically observed equality, U=UD, leads naturally to the hypothesis that these two velocities, the former real and the latter virtual, are, in fact, simply manifestations of the same underlying molecular phenomenon, namely the gas's Brownian movement, albeit biased by the temperature gradient. This purely hydrodynamic continuum-mechanical equality is confirmed by theoretical calculations effected at the kinetic-molecular level on the basis of an existing solution of the Boltzmann equation for a quasi-Lorentzian gas, modulo small uncertainties pertaining to the choice of collision model. Explicitly, this asymptotically valid molecular model allows the virtual drift velocity UD of the light gas and the thermophoretic velocity U of the massive, effectively non-Brownian, particle, now regarded as the tracer particle of the light gas's drift velocity, to each be identified with the Chapman-Enskog "thermal diffusion velocity" of the quasi-Lorentzian gas, here designated by the symbol UM/M, as calculated by de la Mora and Mercer. It is further pointed out that, modulo the collective uncertainties cited above, the common velocities UD,U, and UM/M are identical to the single-component gas's diffuse volume current jv, the latter representing yet another, independent, strictly continuum-mechanical concept. Finally, comments are offered on the extension of the single-component drift velocity notion to liquids, and its application towards rationalizing Soret thermal-diffusion separation phenomena in quasi-Lorentzian liquid-phase binary mixtures composed of disparately sized solute and solvent molecules, with the massive Brownian solute molecules (e.g., colloidal particles) present in disproportionately small amounts relative to that of the solvent.

Enabling Tools and Methods for International, Inter-disciplinary and Educational Collaboration

NASA Astrophysics Data System (ADS)

Robinson, E. M.; Hoijarvi, K.; Falke, S.; Fialkowski, E.; Kieffer, M.; Husar, R. B.

2008-05-01

In the past, collaboration has taken place in tightly-knit workgroups where the members had direct connections to each other. Such collaboration was confined to small workgroups and person-to-person communication. Recent developments through the Internet foster virtual workgroups and organizations where dynamic, 'just-in-time' collaboration can take place over a much larger scale. The emergence of virtual workgroups has strongly influenced the interaction of inter-national, inter-disciplinary, as well as educational activities. In this paper we present an array of enabling tools and methods that incorporate the new technologies including web services, software mashups, tag-based structuring and searching, and wikis for collaborative writing and content organization. Large monolithic, 'do-it-all' software tools are giving way to web service modules, combined through service chaining. Application software can now be created using Service Oriented Architecture (SOA). In the air quality community, data providers and users are distributed in space and time creating barriers for data access. By exposing the data on the internet the space, time barriers are lessened. The federated data system, DataFed, developed at Washington University, accesses data from autonomous, distributed providers. Through data "wrappers", DataFed provides uniform and standards-based access services to heterogeneous, distributed data. Service orientation not only lowers the entry resistance for service providers, but it also allows the creation of user-defined applications and/or mashups. For example, Google Earth's open API allowed many groups to mash their content with Google Earth. Ad hoc tagging gives a rich description of the internet resources, but it has the disadvantage of providing a fuzzy schema. The semantic uniformity of the internet resources can be improved by controlled tagging which apply a consistent namespace and tag combinations to diverse objects. One example of this is the photo-sharing web application Flickr. Just like data, by exposing photos through the internet those can be reused in ways unknown and unanticipated by the provider. For air quality application, Flickr allowed a rich collection of images of forest fire smoke, wind blown dust and haze events to be tagged with controlled tags and used in for evaluating subtle features of the events. Wikis, originally used just for collaboratively writing and discuss documents, are now also a social software workflow managers. In air quality data, wikis provides the means to collaboratively create rich metadata. Wikis become a virtual meeting place to discuss ideas before a workshop of conference, display tagged internet resources, and collaboratively work on documents. Wikis are also useful in the classroom. For instance in class projects, the wiki displays harvested resources, maintains collaborative documents and discussions and is the organizational memory for the project.

Aerodynamic loads on a Darrieus rotor blade

NASA Astrophysics Data System (ADS)

Wilson, R. E.; McKie, W. R.; Lissaman, P. B. S.; James, M.

1983-03-01

A method is presented for the free vortex analysis of a Darrieus rotor blade in nonsteady motion, which employs the circle theorem to map the moving rotor airfoil into the circle plane and models the wake generated in terms of point vortices. Nascent vortex strength and position are taken from the Kutta condition, so that the nascent vortex has the same strength as a vortex sheet of uniform strength. Pressure integration over the plate and wake vortex impulse methods yields the same numerical results. The numerical results presented for a one-bladed Darrieus rotor at a tip/speed ratio of three, and two different chord sizes, indicate that the moment on the blade can be adequately approximated by quasi-steady relationships, although the accurate determination of local velocity and circulation are still required.

International Society for Heart and Lung Transplantation working formulation of a standardized nomenclature for cardiac allograft vasculopathy-2010.

PubMed

Mehra, Mandeep R; Crespo-Leiro, Maria G; Dipchand, Anne; Ensminger, Stephan M; Hiemann, Nicola E; Kobashigawa, Jon A; Madsen, Joren; Parameshwar, Jayan; Starling, Randall C; Uber, Patricia A

2010-07-01

The development of cardiac allograft vasculopathy remains the Achilles heel of cardiac transplantation. Unfortunately, the definitions of cardiac allograft vasculopathy are diverse, and there are no uniform international standards for the nomenclature of this entity. This consensus document, commissioned by the International Society of Heart and Lung Transplantation Board, is based on best evidence and clinical consensus derived from critical analysis of available information pertaining to angiography, intravascular ultrasound imaging, microvascular function, cardiac allograft histology, circulating immune markers, non-invasive imaging tests, and gene-based and protein-based biomarkers. This document represents a working formulation for an international nomenclature of cardiac allograft vasculopathy, similar to the development of the system for adjudication of cardiac allograft rejection by histology.

Circulating protein synthesis rates reveal skeletal muscle proteome dynamics

PubMed Central

Shankaran, Mahalakshmi; King, Chelsea L.; Angel, Thomas E.; Holmes, William E.; Li, Kelvin W.; Colangelo, Marc; Price, John C.; Turner, Scott M.; Bell, Christopher; Hamilton, Karyn L.; Miller, Benjamin F.; Hellerstein, Marc K.

2015-01-01

Here, we have described and validated a strategy for monitoring skeletal muscle protein synthesis rates in rodents and humans over days or weeks from blood samples. We based this approach on label incorporation into proteins that are synthesized specifically in skeletal muscle and escape into the circulation. Heavy water labeling combined with sensitive tandem mass spectrometric analysis allowed integrated synthesis rates of proteins in muscle tissue across the proteome to be measured over several weeks. Fractional synthesis rate (FSR) of plasma creatine kinase M-type (CK-M) and carbonic anhydrase 3 (CA-3) in the blood, more than 90% of which is derived from skeletal muscle, correlated closely with FSR of CK-M, CA-3, and other proteins of various ontologies in skeletal muscle tissue in both rodents and humans. Protein synthesis rates across the muscle proteome generally changed in a coordinate manner in response to a sprint interval exercise training regimen in humans and to denervation or clenbuterol treatment in rodents. FSR of plasma CK-M and CA-3 revealed changes and interindividual differences in muscle tissue proteome dynamics. In human subjects, sprint interval training primarily stimulated synthesis of structural and glycolytic proteins. Together, our results indicate that this approach provides a virtual biopsy, sensitively revealing individualized changes in proteome-wide synthesis rates in skeletal muscle without a muscle biopsy. Accordingly, this approach has potential applications for the diagnosis, management, and treatment of muscle disorders. PMID:26657858

Cell-free microRNAs as diagnostic, prognostic, and predictive biomarkers for lung cancer.

PubMed

Zandberga, Elīna; Kozirovskis, Viktors; Ābols, Artūrs; Andrējeva, Diāna; Purkalne, Gunta; Linē, Aija

2013-04-01

Lung cancer is the most common cancer worldwide, accounting for over 1.37 million deaths annually. The clinical outcome and management of lung cancer patients could be substantially improved by the implementation of non-invasive biomarker assays for the early detection, prognosis as well as prediction and monitoring of treatment response. MicroRNAs (miRNAs) have been implicated in the regulation of virtually all signaling circuits within a cell and their dysregulation has been shown to play an essential role in the development and progression of cancer. Recently, miRNAs were found to be released into the circulation and to exist there in a remarkably stable form. Furthermore, various cancers were shown to leave specific miRNA fingerprints in the blood of patients suggesting that cell-free miRNAs could serve as non-invasive biomarkers for the detection or monitoring of cancer and putative therapeutic targets. Since that, a considerable effort has been devoted to decode the information carried by circulating miRNAs. In the current review, we give an insight into the mechanisms of miRNA release into the bloodstream, their putative functional significance and systematically review the studies focused on the identification of cell-free miRNAs with the diagnostic, prognostic, and predictive significance in lung cancer and discuss their potential clinical utility. Copyright © 2012 Wiley Periodicals, Inc.

Pulmonary function in space

NASA Technical Reports Server (NTRS)

West, J. B.; Elliott, A. R.; Guy, H. J.; Prisk, G. K.

1997-01-01

The lung is exquisitely sensitive to gravity, and so it is of interest to know how its function is altered in the weightlessness of space. Studies on National Aeronautics and Space Administration (NASA) Spacelabs during the last 4 years have provided the first comprehensive data on the extensive changes in pulmonary function that occur in sustained microgravity. Measurements of pulmonary function were made on astronauts during space shuttle flights lasting 9 and 14 days and were compared with extensive ground-based measurements before and after the flights. Compared with preflight measurements, cardiac output increased by 18% during space flight, and stroke volume increased by 46%. Paradoxically, the increase in stroke volume occurred in the face of reductions in central venous pressure and circulating blood volume. Diffusing capacity increased by 28%, and the increase in the diffusing capacity of the alveolar membrane was unexpectedly large based on findings in normal gravity. The change in the alveolar membrane may reflect the effects of uniform filling of the pulmonary capillary bed. Distributions of blood flow and ventilation throughout the lung were more uniform in space, but some unevenness remained, indicating the importance of nongravitational factors. A surprising finding was that airway closing volume was approximately the same in microgravity and in normal gravity, emphasizing the importance of mechanical properties of the airways in determining whether they close. Residual volume was unexpectedly reduced by 18% in microgravity, possibly because of uniform alveolar expansion. The findings indicate that pulmonary function is greatly altered in microgravity, but none of the changes observed so far will apparently limit long-term space flight. In addition, the data help to clarify how gravity affects pulmonary function in the normal gravity environment on Earth.

Microscopic endometrial perivascular epithelioid cell nodules: a case report with the earliest presentation of a uterine perivascular epithelioid cell tumor

PubMed Central

2012-01-01

Abstract Perivascular epithelioid cell (PEC) tumors (PEComas) are a family of related mesenchymal tumors composed of PECs which co-express melanocytic and smooth muscle markers. Although their distinctive histologic, immunohistochemical, ultrastructural, and genetic features have been clearly demonstrated, their histogenesis and normal counterpart remain largely unknown. Precursor lesions of PEComas have rarely been reported. We herein describe a tuberous sclerosis patient with microscopic PEC nodules in the endometrium of adenomyosis, pelvic endometriosis, an ovarian endometriotic cyst, and the endometrium of the uterine cavity. The nodules showed a mixture of spindle-shaped and epithelioid cells concentrically arranged around small arteries. The cells exhibited uniform nuclei, light eosinophilic cytoplasm, and immunoreactivity with HMB-45 and CD10. Some nodules revealed continuity with a PEComa in the myometrium. These findings support microscopic endometrial PEC nodules possibly being precursor lesions of uterine PEComas. The wide distribution of the nodules in the pelvis may be related to the multicentricity of PEComas in tuberous sclerosis patients. Owing to the immunoreactivity with CD10, microscopic endometrial PEC nodules may be misinterpreted as endothelial stromal cells unless melanocytic markers are stained. To the best of our knowledge, this is a case with the earliest manifestation of PEC lesions occurring in the endometrium. Virtual Slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9658280017862643 PMID:22937790

Microscopic endometrial perivascular epithelioid cell nodules: a case report with the earliest presentation of a uterine perivascular epithelioid cell tumor.

PubMed

Fang, Chia-Lang; Lin, Yun-Ho; Chen, Wei-Yu

2012-09-03

Perivascular epithelioid cell (PEC) tumors (PEComas) are a family of related mesenchymal tumors composed of PECs which co-express melanocytic and smooth muscle markers. Although their distinctive histologic, immunohistochemical, ultrastructural, and genetic features have been clearly demonstrated, their histogenesis and normal counterpart remain largely unknown. Precursor lesions of PEComas have rarely been reported. We herein describe a tuberous sclerosis patient with microscopic PEC nodules in the endometrium of adenomyosis, pelvic endometriosis, an ovarian endometriotic cyst, and the endometrium of the uterine cavity. The nodules showed a mixture of spindle-shaped and epithelioid cells concentrically arranged around small arteries. The cells exhibited uniform nuclei, light eosinophilic cytoplasm, and immunoreactivity with HMB-45 and CD10. Some nodules revealed continuity with a PEComa in the myometrium. These findings support microscopic endometrial PEC nodules possibly being precursor lesions of uterine PEComas. The wide distribution of the nodules in the pelvis may be related to the multicentricity of PEComas in tuberous sclerosis patients. Owing to the immunoreactivity with CD10, microscopic endometrial PEC nodules may be misinterpreted as endothelial stromal cells unless melanocytic markers are stained. To the best of our knowledge, this is a case with the earliest manifestation of PEC lesions occurring in the endometrium. Virtual slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9658280017862643.

An IBEM solution to the scattering of plane SH-waves by a lined tunnel in elastic wedge space

NASA Astrophysics Data System (ADS)

Liu, Zhongxian; Liu, Lei

2015-02-01

The indirect boundary element method (IBEM) is developed to solve the scattering of plane SH-waves by a lined tunnel in elastic wedge space. According to the theory of single-layer potential, the scattered-wave field can be constructed by applying virtual uniform loads on the surface of lined tunnel and the nearby wedge surface. The densities of virtual loads can be solved by establishing equations through the continuity conditions on the interface and zero-traction conditions on free surfaces. The total wave field is obtained by the superposition of free field and scattered-wave field in elastic wedge space. Numerical results indicate that the IBEM can solve the diffraction of elastic wave in elastic wedge space accurately and efficiently. The wave motion feature strongly depends on the wedge angle, the angle of incidence, incident frequency, the location of lined tunnel, and material parameters. The waves interference and amplification effect around the tunnel in wedge space is more significant, causing the dynamic stress concentration factor on rigid tunnel and the displacement amplitude of flexible tunnel up to 50.0 and 17.0, respectively, more than double that of the case of half-space. Hence, considerable attention should be paid to seismic resistant or anti-explosion design of the tunnel built on a slope or hillside.

Output feedback control of a quadrotor UAV using neural networks.

PubMed

Dierks, Travis; Jagannathan, Sarangapani

2010-01-01

In this paper, a new nonlinear controller for a quadrotor unmanned aerial vehicle (UAV) is proposed using neural networks (NNs) and output feedback. The assumption on the availability of UAV dynamics is not always practical, especially in an outdoor environment. Therefore, in this work, an NN is introduced to learn the complete dynamics of the UAV online, including uncertain nonlinear terms like aerodynamic friction and blade flapping. Although a quadrotor UAV is underactuated, a novel NN virtual control input scheme is proposed which allows all six degrees of freedom (DOF) of the UAV to be controlled using only four control inputs. Furthermore, an NN observer is introduced to estimate the translational and angular velocities of the UAV, and an output feedback control law is developed in which only the position and the attitude of the UAV are considered measurable. It is shown using Lyapunov theory that the position, orientation, and velocity tracking errors, the virtual control and observer estimation errors, and the NN weight estimation errors for each NN are all semiglobally uniformly ultimately bounded (SGUUB) in the presence of bounded disturbances and NN functional reconstruction errors while simultaneously relaxing the separation principle. The effectiveness of proposed output feedback control scheme is then demonstrated in the presence of unknown nonlinear dynamics and disturbances, and simulation results are included to demonstrate the theoretical conjecture.

Wide-range radioactive-gas-concentration detector

DOEpatents

Anderson, D.F.

1981-11-16

A wide-range radioactive-gas-concentration detector and monitor capable of measuring radioactive-gas concentrations over a range of eight orders of magnitude is described. The device is designed to have an ionization chamber sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel-plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel-plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization-chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.

Vortex Filaments in Grids for Scalable, Fine Smoke Simulation.

PubMed

Meng, Zhang; Weixin, Si; Yinling, Qian; Hanqiu, Sun; Jing, Qin; Heng, Pheng-Ann

2015-01-01

Vortex modeling can produce attractive visual effects of dynamic fluids, which are widely applicable for dynamic media, computer games, special effects, and virtual reality systems. However, it is challenging to effectively simulate intensive and fine detailed fluids such as smoke with fast increasing vortex filaments and smoke particles. The authors propose a novel vortex filaments in grids scheme in which the uniform grids dynamically bridge the vortex filaments and smoke particles for scalable, fine smoke simulation with macroscopic vortex structures. Using the vortex model, their approach supports the trade-off between simulation speed and scale of details. After computing the whole velocity, external control can be easily exerted on the embedded grid to guide the vortex-based smoke motion. The experimental results demonstrate the efficiency of using the proposed scheme for a visually plausible smoke simulation with macroscopic vortex structures.

Labview Interface Concepts Used in NASA Scientific Investigations and Virtual Instruments

NASA Technical Reports Server (NTRS)

Roth, Don J.; Parker, Bradford H.; Rapchun, David A.; Jones, Hollis H.; Cao, Wei

2001-01-01

This article provides an overview of several software control applications developed for NASA using LabVIEW. The applications covered here include (1) an Ultrasonic Measurement System for nondestructive evaluation of advanced structural materials, an Xray Spectral Mapping System for characterizing the quality and uniformity of developing photon detector materials, (2) a Life Testing System for these same materials, (3) and the instrument panel for an aircraft mounted Cloud Absorption Radiometer that measures the light scattered by clouds in multiple spectral bands. Many of the software interface concepts employed are explained. Panel layout and block diagram (code) strategies for each application are described. In particular, some of the more unique features of the applications' interfaces and source code are highlighted. This article assumes that the reader has a beginner-to-intermediate understanding of LabVIEW methods.

Composite lithium metal anode by melt infusion of lithium into a 3D conducting scaffold with lithiophilic coating.

PubMed

Liang, Zheng; Lin, Dingchang; Zhao, Jie; Lu, Zhenda; Liu, Yayuan; Liu, Chong; Lu, Yingying; Wang, Haotian; Yan, Kai; Tao, Xinyong; Cui, Yi

2016-03-15

Lithium metal-based battery is considered one of the best energy storage systems due to its high theoretical capacity and lowest anode potential of all. However, dendritic growth and virtually relative infinity volume change during long-term cycling often lead to severe safety hazards and catastrophic failure. Here, a stable lithium-scaffold composite electrode is developed by lithium melt infusion into a 3D porous carbon matrix with "lithiophilic" coating. Lithium is uniformly entrapped on the matrix surface and in the 3D structure. The resulting composite electrode possesses a high conductive surface area and excellent structural stability upon galvanostatic cycling. We showed stable cycling of this composite electrode with small Li plating/stripping overpotential (<90 mV) at a high current density of 3 mA/cm(2) over 80 cycles.

Recrystallization characteristics of oxide dispersion strengthened nickel-base alloys

NASA Technical Reports Server (NTRS)

Hotzler, R. K.; Glasgow, T. K.

1980-01-01

Electron microscopy was employed to study the process of recrystallization in two oxide dispersion strengthened (ODS) mechanically alloyed nickel-base alloys, MA 754 and MA 6000E. MA 754 contained both fine, uniformly dispersed particles and coarser oxides aligned along the working direction. Hot rolled MA 754 had a grain size of 0.5 microns and high dislocation densities. After partial primary recrystallization, the fine grains transformed to large elongated grains via secondary (or abnormal) grain growth. Extruded and rolled MA 6000E contained equiaxed grains of 0.2 micron diameter. Primary recrystallization occurring during working eliminated virtually all dislocations. Conversion from fine to coarse grains was triggered by gamma prime dissolution; this was also a process of secondary or abnormal grain growth. Comparisons were made to conventional and oxide dispersion strengthened nickel-base alloys.

The Role of Atmospheric Deposition on the Input of Trace Elements to the Surface Ocean: the Bermuda Wet and Dry Record

NASA Astrophysics Data System (ADS)

Church, T. M.; Sedwick, P. N.; Sholkovitz, E. R.

2011-12-01

Global surface temperature variations and changes result from intricate interplay of phenomena varying on scales ranging from fraction of seconds (turbulence) to thousands of years (e.g. glaciations). To complicate these issues further, the contribution of the anthropogenic forcing on the observed changes in surface temperatures varies over time and is spatially non-uniform. While evaluating all individual bands of this broad spectrum is virtually impossible, the availability of global daily datasets in the last few decades from reanalyses and Global Climate Models (GCMs) simulations allows estimating the contribution of phenomena varying on synoptic-to-interannual timescales. Previous studies using GCM simulations for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment (IPCC AR4) have documented a consistent poleward shift in the storm tracks related to changes in baroclinicity resulting from global warming. However, our recent research (Cannon et al. 2013) indicated that the pattern of changes in the storm tracks observed in the last few decades is much more complex in both space and time. Complex terrain and the relative distribution of continents, oceans and icecaps play a significant role for changes in synoptic activity. Coupled modes such as the Northern and Southern annular modes, the El Nino-Southern Oscillation (ENSO) and respective teleconnections with changes in baroclinicity have been identified as relevant dynamical forcings for variations of the midlatitude storm tracks, increasing the uncertainties in future projections. Moreover, global warming has modified the amplitude of the annual cycles of temperature, moisture and circulation throughout the planet and there is strong indication that these changes have mostly affected the tropics and Polar Regions. The present study advances these findings by investigating the 'blue-shift' in the underlying dynamics causing surface temperature anomalies and investigates relationships with low and upper level circulation. This research uses two sources of data: global daily Climate Forecast System Reanalysis (CFSR) (1979- 2010) and the Geophysical Fluid Dynamics Laboratory (GFDL) global daily simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Two sets of simulations are investigated: the Historic and Pi-control runs. Here the term ';blue-shift' is used to indicate long-term increase in the amplitude of the synoptic scale relatively to the annual cycle amplitude derived from wavelet analysis as an analogy to the definition commonly used in physics (i.e., a shift toward shorter wavelengths of the spectral lines). It is shown that the blue-shift has been observed in midlatitudes of some continental areas of the Northern Hemisphere and North Pacific but in relatively higher latitudes in the Southern Hemisphere. Tropical areas and high latitudes of the Northern Hemisphere have experienced opposite trend (red-shift). Moreover, the pattern of the blue and red-shifts exhibits seasonal changes. References: Cannon, F., L. M. V. Carvalho, C. Jones, B. Bookhagen, 2013: Multi-Annual Variations in Winter Westerly Disturbance Activity Affecting the Himalaya. Submitted to Climate Dynamics

The 'Blue-Shift' in midlatitude dynamics in a Changing Climate

NASA Astrophysics Data System (ADS)

Carvalho, L. V.

2013-12-01

Global surface temperature variations and changes result from intricate interplay of phenomena varying on scales ranging from fraction of seconds (turbulence) to thousands of years (e.g. glaciations). To complicate these issues further, the contribution of the anthropogenic forcing on the observed changes in surface temperatures varies over time and is spatially non-uniform. While evaluating all individual bands of this broad spectrum is virtually impossible, the availability of global daily datasets in the last few decades from reanalyses and Global Climate Models (GCMs) simulations allows estimating the contribution of phenomena varying on synoptic-to-interannual timescales. Previous studies using GCM simulations for the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment (IPCC AR4) have documented a consistent poleward shift in the storm tracks related to changes in baroclinicity resulting from global warming. However, our recent research (Cannon et al. 2013) indicated that the pattern of changes in the storm tracks observed in the last few decades is much more complex in both space and time. Complex terrain and the relative distribution of continents, oceans and icecaps play a significant role for changes in synoptic activity. Coupled modes such as the Northern and Southern annular modes, the El Nino-Southern Oscillation (ENSO) and respective teleconnections with changes in baroclinicity have been identified as relevant dynamical forcings for variations of the midlatitude storm tracks, increasing the uncertainties in future projections. Moreover, global warming has modified the amplitude of the annual cycles of temperature, moisture and circulation throughout the planet and there is strong indication that these changes have mostly affected the tropics and Polar Regions. The present study advances these findings by investigating the 'blue-shift' in the underlying dynamics causing surface temperature anomalies and investigates relationships with low and upper level circulation. This research uses two sources of data: global daily Climate Forecast System Reanalysis (CFSR) (1979- 2010) and the Geophysical Fluid Dynamics Laboratory (GFDL) global daily simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5). Two sets of simulations are investigated: the Historic and Pi-control runs. Here the term ';blue-shift' is used to indicate long-term increase in the amplitude of the synoptic scale relatively to the annual cycle amplitude derived from wavelet analysis as an analogy to the definition commonly used in physics (i.e., a shift toward shorter wavelengths of the spectral lines). It is shown that the blue-shift has been observed in midlatitudes of some continental areas of the Northern Hemisphere and North Pacific but in relatively higher latitudes in the Southern Hemisphere. Tropical areas and high latitudes of the Northern Hemisphere have experienced opposite trend (red-shift). Moreover, the pattern of the blue and red-shifts exhibits seasonal changes. References: Cannon, F., L. M. V. Carvalho, C. Jones, B. Bookhagen, 2013: Multi-Annual Variations in Winter Westerly Disturbance Activity Affecting the Himalaya. Submitted to Climate Dynamics

Impact of Preferred Eddy Tracks on Transport and Mixing in the Eastern South Pacific

NASA Astrophysics Data System (ADS)

Belmadani, A.; Donoso, D.; Auger, P. A.; Chaigneau, A.

2017-12-01

Mesoscale eddies, which play a fundamental role in the transport of mass, heat, nutrients, and biota across the oceans, have been suggested to propagate preferently along specific tracks. These preferred pathways, also called eddy trains, are near-zonal due to westward drift of individual vortices, and tend to be polarized (ie alternatively dominated by anticyclonic/cyclonic eddies), coinciding with the recently discovered latent striations (quasi-zonal mesoscale jet-like features). While significant effort has been made to understand the dynamics of striations and their interplay with mesoscale eddies, the impact of repeated eddy tracks on physical (temperature, salinity), biogeochemical (oxygen, carbon, nutrients) and other tracers (e.g. chlorophyll, marine debris) has received little attention. Here we report on the results of numerical modeling experiments that simulate the impact of preferred eddy tracks on the transport and mixing of water particles in the Eastern South Pacific off Chile. A 30-year interannual simulation of the oceanic circulation in this region has been performed over 1984-2013 with the ROMS (Regional Oceanic Modeling System) at an eddy-resolving resolution (10 km). Objective tracking of mesoscale coherent vortices is obtained using automated methods, allowing to compute the contribution of eddies to the ocean circulation. Preferred eddy tracks are further isolated from the more random eddies, by comparing the distances between individual tracks and the striated pattern in long-term mean eddy polarity with a least-squares approach. The remaining non-eddying flow may also be decomposed into time-mean and anomalous circulation, and/or small- and large-scale circulation. Neutrally-buoyant Lagrangian floats are then released uniformly into the various flow components as well as the total flow, and tracked forward in time with the ARIANE software. The dispersion patterns of water particles are used to estimate the respective contributions of organized and random eddies, mean flow, large-scale perturbations etc. to mixing properties and transport pathways. Float release into the full flow inside selected vortices is also used to document the impact of eddy trains on the transformation of water masses inferred from changes in temperature/salinity along float trajectories.

Critical issues in medical education and the implications for telemedicine technology.

PubMed

Mahapatra, Ashok Kumar; Mishra, Saroj Kanta; Kapoor, Lily; Singh, Indra Pratap

2009-01-01

Ensuring quality medical education in all the medical colleges across India based on uniform curriculum prescribed by a regulatory body and maintaining a uniform standard are dependent on availability of an excellent infrastructure. Such infrastructure includes qualified teachers, knowledge resources, learning materials, and advanced education technology, which is a challenge in developing countries due to financial and logistic constraints. Advancement in telecommunication, information science, and technology provides an opportunity to exchange knowledge and skill across geographically dispersed organizations by networking academic medical centers of excellence with medical colleges and institutes to practice distance learning using information and communication technology (ICT)-based tools. These may be as basic as commonly used Web-based tools or may be as advanced as virtual reality, simulation, and telepresence-based collaborative learning environment. The scenario in India is no different from any developing country, but there is considerable progress due to technical advancement in these sectors. Telemedicine and tele-education in health science, is gradually getting adopted into the Indian Health System after decade-long pilot studies across the country. A recent recommendation of the National Knowledge Commission, once implemented, would ensure a gigabyte network across all the educational institutions of the country including medical colleges. Availability of indigenous satellite communication technology and the government policy of free bandwidth provision for societal development sector have added strength to set up infrastructure to pilot several telemedicine educational projects across the country.

Constraints on cooling of the lower ocean crust from epidote veins in the Wadi Gideah section, Oman Ophiolite

NASA Astrophysics Data System (ADS)

Diehl, Alexander; Bieseler, Bastian; Bach, Wolfgang

2017-04-01

Determining the depth, extent, and timing of high-temperature hydrothermal alteration in the ocean crust is key to understanding how the lower oceanic crust is cooled. We report data from 18 epidote veins from the Wadi Gideah section in the Wadi Tayin block, which is a reference section for alteration of the lower crust formed at a fast oceanic spreading center. 87Sr/86Sr ratios feature a narrow range from 0.70429 to 0.70512, while O isotope compositions vary between - 0.7 and +4.9‰ in δ18OSMOW. These compositions indicate uniform water-rock ratios between 1 and 2 and formation temperatures in the range of 300 to 450˚ C. There is no systematic trend in Sr and O isotope compositions down section. Fluid inclusion entrapment temperatures for a subset of four samples linearly increase from 338˚ C to 465˚ C in lowermost 3 km of crust of the Wadi Gideah section. Salinities are uniform throughout and scatter closely around seawater values. We developed a numerical cooling model to assign possible crustal ages to the thermal gradients observed. For pure conductive cooling, these ages range between 4 and 20 Ma. Our thermal model runs with a high Nusselt number (Nu) of 20 down to the base of the crust indicate that the epidote veins may record this near-axial deep circulation in crust of only 0.1 Ma (5-7 km off axis). When off-axis circulation is shut off in the more distal flanks, however, massive conductive reheating of the lower crust by as much as 200˚ C is predicted to take place. But there is no evidence for prograde metamorphic reactions in the samples we studied (or other hydrothermally altered oceanic gabbros). An intermediate model, in which Nu is 20 down to 2 km for the first 0.1 Ma and Nu is then 4 down to 6.5 km depth off axis to 1 Ma, is consistent with the permeability distribution within the ocean crust and predicts a thermal gradient for the lower crust that matches the observed one for ages between 1 and 3 Ma. The most plausible explanation for the origin of the epidote veins is that they formed in off-axial hydrothermal systems that reach the base of the crust within 50-150 km off the axis. This deep circulation provides an efficient mechanism for mining heat that escapes the crust in the young flanks of mid-ocean ridges where a sizeable fraction of the global oceanic hydrothermal heat flux is expected to take place.

Targeted delivery of anti-tuberculosis drugs to macrophages: targeting mannose receptors

NASA Astrophysics Data System (ADS)

Filatova, L. Yu; Klyachko, N. L.; Kudryashova, E. V.

2018-04-01

The development of systems for targeted delivery of anti-tuberculosis drugs is a challenge of modern biotechnology. Currently, these drugs are encapsulated in a variety of carriers such as liposomes, polymers, emulsions and so on. Despite successful in vitro testing of these systems, virtually no success was achieved in vivo, because of low accessibility of the foci of infection located in alveolar macrophage cells. A promising strategy for increasing the efficiency of therapeutic action of anti-tuberculosis drugs is to encapsulate the agents into mannosylated carriers targeting the mannose receptors of alveolar macrophages. The review addresses the methods for modification of drug substance carriers, such as liposomes and biodegradable polymers, with mannose residues. The use of mannosylated carriers to deliver anti-tuberculosis agents increases the drug circulation time in the blood stream and increases the drug concentration in alveolar macrophage cells. The bibliography includes 113 references.

A Versatile Microarray Platform for Capturing Rare Cells

NASA Astrophysics Data System (ADS)

Brinkmann, Falko; Hirtz, Michael; Haller, Anna; Gorges, Tobias M.; Vellekoop, Michael J.; Riethdorf, Sabine; Müller, Volkmar; Pantel, Klaus; Fuchs, Harald

2015-10-01

Analyses of rare events occurring at extremely low frequencies in body fluids are still challenging. We established a versatile microarray-based platform able to capture single target cells from large background populations. As use case we chose the challenging application of detecting circulating tumor cells (CTCs) - about one cell in a billion normal blood cells. After incubation with an antibody cocktail, targeted cells are extracted on a microarray in a microfluidic chip. The accessibility of our platform allows for subsequent recovery of targets for further analysis. The microarray facilitates exclusion of false positive capture events by co-localization allowing for detection without fluorescent labelling. Analyzing blood samples from cancer patients with our platform reached and partly outreached gold standard performance, demonstrating feasibility for clinical application. Clinical researchers free choice of antibody cocktail without need for altered chip manufacturing or incubation protocol, allows virtual arbitrary targeting of capture species and therefore wide spread applications in biomedical sciences.

How shorter black carbon lifetime alters its climate effect.

PubMed

Hodnebrog, Øivind; Myhre, Gunnar; Samset, Bjørn H

2014-09-25

Black carbon (BC), unlike most aerosol types, absorbs solar radiation. However, the quantification of its climate impact is uncertain and presently under debate. Recently, attention has been drawn both to a likely underestimation of global BC emissions in climate models, and an overestimation of BC at high altitudes. Here we show that doubling present day BC emissions in a model simulation, while reducing BC lifetime based on observational evidence, leaves the direct aerosol effect of BC virtually unchanged. Increased emissions, together with increased wet removal that reduces the lifetime, yields modelled BC vertical profiles that are in strongly improved agreement with recent aircraft observations. Furthermore, we explore the consequences of an altered BC profile in a global circulation model, and show that both the vertical profile of BC and rapid climate adjustments need to be taken into account in order to assess the total climate impact of BC.

Magnetic resonance imaging-guided surgical design: can we optimise the Fontan operation?

PubMed

Haggerty, Christopher M; Yoganathan, Ajit P; Fogel, Mark A

2013-12-01

The Fontan procedure, although an imperfect solution for children born with a single functional ventricle, is the only reconstruction at present short of transplantation. The haemodynamics associated with the total cavopulmonary connection, the modern approach to Fontan, are severely altered from the normal biventricular circulation and may contribute to the long-term complications that are frequently noted. Through recent technological advances, spear-headed by advances in medical imaging, it is now possible to virtually model these surgical procedures and evaluate the patient-specific haemodynamics as part of the pre-operative planning process. This is a novel paradigm with the potential to revolutionise the approach to Fontan surgery, help to optimise the haemodynamic results, and improve patient outcomes. This review provides a brief overview of these methods, presents preliminary results of their clinical usage, and offers insights into its potential future directions.

The Application of Jason-Measurements to Estimate the Global Near Surface Ocean Circulation for Climate Research

NASA Technical Reports Server (NTRS)

Niiler, Pearn P.

2004-01-01

The scientific objective of this research program were to utilize drifter and satellite sea level data for the determination of time mean and time variable surface currents of the global ocean. To accomplish these tasks has required the processing of drifter data to include a wide variety of different configurations of drifters into a uniform format and to process the along track satellite altimeter data for computing the geostrophic current components normal to the track. These tasks were accomplished, which resulted in an increase of drifter data by about 40% and the development of new algorithms for obtaining satellite derived geostrophic velocity data that was consistent with the drifter observations of geostrophic time-variable currents. The methodologies and the research results using these methodologies were reported in the publications listed in this paper.

SAR observations in the Gulf of Mexico

NASA Technical Reports Server (NTRS)

Sheres, David

1992-01-01

The Gulf of Mexico (GOM) exhibits a wealth of energetic ocean features; they include the Loop Current with velocities of about 2 m/s and strong shear fronts, mesoscale eddies, double vortices, internal waves, and the outflow of the 'Mighty Mississippi' river. These energetic features can have a strong impact on the economies of the states surrounding the Gulf. Large fisheries, oil and gas production as well as pollution transport are relevant issues. These circulation features in the Gulf are invisible to conventional IR and visible satellite imagery during the Summer months due to cloud cover and uniform surface temperatures. Synthetic Aperture Radar (SAR) imagery of the Gulf does penetrate the cloud cover and shows a rich assembly of features there year-round. Below are preliminary results from GOM SAR imagery taken by SEASAT in 1978 and by the AIRSAR program in 1991.

Vinyl chloride removal from an air stream by biotrickling filter.

PubMed

Faraj, S H Esmaeili; Esfahany, M Nasr; Kadivar, M; Zilouei, H

2012-01-01

A biofiltration process was used for degradation of vinyl chloride as a hazardous material in the air stream. Three biotrickling filters in series-parallel allowing uniform feed and moisture distribution all over the bed were used. Granular activated carbon mixed with compost was employed as carrier bed. The biological culture consisted of mixture of activated sludge from PVC wastewater treatment plant. Concurrent flow of gas and liquid was used in the bed. Results indicated that during the operation period of 110 days, the biotrickling bed was able to remove over 35% of inlet vinyl chloride. Maximum elimination capacity was calculated to be 0.56 g.m(-3).hr(-1). The amount of chlorine accumulated in the circulating liquid due to the degradation of vinyl chloride was measured to be equal to the vinyl chloride removed from the air stream.

Single-Cell Whole-Genome Amplification and Sequencing: Methodology and Applications.

PubMed

Huang, Lei; Ma, Fei; Chapman, Alec; Lu, Sijia; Xie, Xiaoliang Sunney

2015-01-01

We present a survey of single-cell whole-genome amplification (WGA) methods, including degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR), multiple displacement amplification (MDA), and multiple annealing and looping-based amplification cycles (MALBAC). The key parameters to characterize the performance of these methods are defined, including genome coverage, uniformity, reproducibility, unmappable rates, chimera rates, allele dropout rates, false positive rates for calling single-nucleotide variations, and ability to call copy-number variations. Using these parameters, we compare five commercial WGA kits by performing deep sequencing of multiple single cells. We also discuss several major applications of single-cell genomics, including studies of whole-genome de novo mutation rates, the early evolution of cancer genomes, circulating tumor cells (CTCs), meiotic recombination of germ cells, preimplantation genetic diagnosis (PGD), and preimplantation genomic screening (PGS) for in vitro-fertilized embryos.

Interbasin effects of the Indian Ocean on Pacific decadal climate change

NASA Astrophysics Data System (ADS)

Mochizuki, Takashi; Kimoto, Masahide; Watanabe, Masahiro; Chikamoto, Yoshimitsu; Ishii, Masayoshi

2016-07-01

We demonstrate the significant impact of the Indian Ocean on the Pacific climate on decadal timescales by comparing two sets of data assimilation experiments (pacemaker experiments) conducted over recent decades. For the Indian Ocean of an atmosphere-ocean coupled global climate model, we assimilate ocean temperature and salinity anomalies defined as deviations from climatology or as anomalies with the area-averaged changes for the Indian Ocean subtracted. When decadal sea surface temperature (SST) trends are observed to be strong over the Indian Ocean, the equatorial thermocline uniformly deepens, and the model simulates the eastward tendencies of surface wind aloft. Surface winds strongly converge around the maritime continent, and the associated strengthening of the Walker circulation suppresses an increasing trend in the equatorial Pacific SST through ocean thermocline shoaling, similar to common changes associated with seasonal Indian Ocean warming.

Ensemble-Based Parameter Estimation in a Coupled GCM Using the Adaptive Spatial Average Method

DOE PAGES

Liu, Y.; Liu, Z.; Zhang, S.; ...

2014-05-29

Ensemble-based parameter estimation for a climate model is emerging as an important topic in climate research. And for a complex system such as a coupled ocean–atmosphere general circulation model, the sensitivity and response of a model variable to a model parameter could vary spatially and temporally. An adaptive spatial average (ASA) algorithm is proposed to increase the efficiency of parameter estimation. Refined from a previous spatial average method, the ASA uses the ensemble spread as the criterion for selecting “good” values from the spatially varying posterior estimated parameter values; these good values are then averaged to give the final globalmore » uniform posterior parameter. In comparison with existing methods, the ASA parameter estimation has a superior performance: faster convergence and enhanced signal-to-noise ratio.« less

High-resolution 3D MR microangiography of the rat ocular circulation.

PubMed

Shih, Yen-Yu I; Muir, Eric R; Li, Guang; De La Garza, Bryan H; Duong, Timothy Q

2012-07-01

To develop high-spatial-resolution magnetic resonance (MR) microangiography techniques to image the rat ocular circulation. Animal experiments were performed with institutional Animal Care Committee approval. MR microangiography (resolution, 84×84×84 μm or 42×42×84 μm) of the rat eye (eight rats) was performed by using a custom-made small circular surface coil with an 11.7-T MR unit before and after monocrystalline iron oxide nanoparticle (MION) injection. MR microangiography measurements were made during air, oxygen, and carbogen inhalation. From three-dimensional MR microangiography, the retina was virtually flattened to enable en face views of various retinal depths, including the retinal and choroidal vascular layers. Signal intensity changes within the retinal or choroidal arteries and veins associated with gas challenges were analyzed. Statistical analysis was performed by using paired t tests, with P<.05 considered to indicate a significant difference. Bonferroni correction was used to adjust for multiple comparisons. The central retinal artery, long posterior ciliary arteries, and choroidal vasculature could be distinguished on MR microangiograms of the eye. With MR microangiography, retinal arteries and veins could be distinguished on the basis of blood oxygen level-dependent contrast. Carbogen inhalation-enhanced MR microangiography signal intensity in both the retina (P=.001) and choroid (P=.027) compared with oxygen inhalation. Carbogen inhalation showed significantly higher signal intensity changes in the retinal arteries (P=.001, compared with oxygen inhalation), but not in the veins (P=.549). With MION administration, MR microangiography depicted retinal arterial vasoconstriction when the animals were breathing oxygen (P=.02, compared with animals breathing air). MR microangiography of the eye allows depth-resolved imaging of small angiographic details of the ocular circulation. This approach may prove useful in studying microvascular pathologic findings and neurovascular dysfunction in the eye and retina. © RSNA, 2012.

Whole cinnamon and aqueous extracts ameliorate sucrose-induced blood pressure elevations in spontaneously hypertensive rats.

PubMed

Preuss, Harry G; Echard, Bobby; Polansky, Marilyn M; Anderson, Richard

2006-04-01

Many agents (nutrients, nutraceuticals, and drugs) that enhance insulin sensitivity and/or reduce circulating insulin concentrations lower blood pressure (BP). Recently, it was reported that cinnamon has the potential to favorably influence the glucose/insulin system. Accordingly, the purpose of the present study was to examine the effects of dietary cinnamon on systolic BP (SBP), and various glucose- and insulin-related parameters in spontaneously hypertensive rats (SHR). In a series of three experiments, treated SHR eating sucrose and non sucrose containing diets were given various amounts of cinnamon, cinnamon extracts, or chromium. Then various parameters such as: body weight, systolic blood pressure, hematology and blood chemistries were followed for three to four weeks. Diets high in sucrose content are associated with insulin resistance and the elevation of SBP. Addition to diets of cinnamon (8% w/w) reduced the SBP of rats eating sucrose containing diets to virtually the same levels as SHR consuming non sucrose containing (only starch) diets. The presence of cinnamon in the diet also decreased the SBP of SHR consuming a non sucrose-containing diet, suggesting that cinnamon reduces more than just sucrose-induced SBP elevations--perhaps a genetic component(s) of the elevated BP as well. The effects of cinnamon on SBP tended to be dose-dependent. Cinnamon did not decrease the levels of blood glucose, but did lower circulating insulin concentrations. Aqueous extracts of cinnamon also decreased SBP and lowered the circulating levels of fructosamine. Cinnamon is used for flavor and taste in food preparation, but cinnamon may have additional roles in glucose metabolism and BP regulation. Therefore, BP regulation may not only be influenced favorably by limiting the amounts of dietary substances that have negative effects on BP and insulin function but also by the addition of beneficial ones, such as cinnamon, that have positive effects.

Ancestral Components of Admixed Genomes in a Mexican Cohort

PubMed Central

Johnson, Nicholas A.; Coram, Marc A.; Shriver, Mark D.; Romieu, Isabelle; Barsh, Gregory S.; London, Stephanie J.; Tang, Hua

2011-01-01

For most of the world, human genome structure at a population level is shaped by interplay between ancient geographic isolation and more recent demographic shifts, factors that are captured by the concepts of biogeographic ancestry and admixture, respectively. The ancestry of non-admixed individuals can often be traced to a specific population in a precise region, but current approaches for studying admixed individuals generally yield coarse information in which genome ancestry proportions are identified according to continent of origin. Here we introduce a new analytic strategy for this problem that allows fine-grained characterization of admixed individuals with respect to both geographic and genomic coordinates. Ancestry segments from different continents, identified with a probabilistic model, are used to construct and study “virtual genomes” of admixed individuals. We apply this approach to a cohort of 492 parent–offspring trios from Mexico City. The relative contributions from the three continental-level ancestral populations—Africa, Europe, and America—vary substantially between individuals, and the distribution of haplotype block length suggests an admixing time of 10–15 generations. The European and Indigenous American virtual genomes of each Mexican individual can be traced to precise regions within each continent, and they reveal a gradient of Amerindian ancestry between indigenous people of southwestern Mexico and Mayans of the Yucatan Peninsula. This contrasts sharply with the African roots of African Americans, which have been characterized by a uniform mixing of multiple West African populations. We also use the virtual European and Indigenous American genomes to search for the signatures of selection in the ancestral populations, and we identify previously known targets of selection in other populations, as well as new candidate loci. The ability to infer precise ancestral components of admixed genomes will facilitate studies of disease-related phenotypes and will allow new insight into the adaptive and demographic history of indigenous people. PMID:22194699

Profile analysis of after-effects experienced during exposure to several virtual reality environments

NASA Technical Reports Server (NTRS)

Kennedy, Robert S.; Jones, Marshall B.; Lilienthal, Michael G.; Harm, Deborah L.

1994-01-01

Motion sickness symptoms are an unwanted by-product of exposure to virtual environments. This problem is not new and was reported in the early flight simulators and experiments on ego motions and vection. The cardinal symptom of motion sickness is, of course, vomiting, but this symptom is ordinarily preceded by a variety of other symptoms. In his classic studies of motion sickness conducted before and during World War II, G. R. Wendt introduced a three point scale to score motion sickness beyond a vomit/no vomit dichotomy. Later, Navy scientists developed a Motion Sickness Questionnaire (MSQ), originally for use in a slowly rotating room. In the last 20 years the MSQ has been used in a series of studies of air, sea, and space sickness. Only recently, however, has it been appreciated that symptom patterns in the MSQ are not uniform but vary with the way sickness is induced. In seasickness, for example, nausea is the most prominent symptom. In Navy simulators, however, the most common symptom is eye strain, especially when cathode ray tubes are employed in the simulation. The latter result was obtained in a survey of over 1,500 pilot exposures. Using this database, Essex scientists conducted a factor analysis of the MSQ. We found that signs and symptoms of motion sickness fell mainly into three clusters: 1) oculomotor disturbance, 2) nausea and related neurovegetative problems, and 3) disorientation, ataxia, and vertigo. We have since rescored the MSQ results obtained in Navy simulators in terms of these three components. We have also compared these and other profiles obtained from three different vitual reality systems to profiles obtained in sea sickness, space sickness, and alcohol intoxication. We will show examples of these various profiles and point out simularities and differences among them which indicate aspects of what might be called 'virtual-reality sickness'.

Classification of Cowpox Viruses into Several Distinct Clades and Identification of a Novel Lineage

PubMed Central

Franke, Annika; Pfaff, Florian; Jenckel, Maria; Hoffmann, Bernd; Höper, Dirk; Antwerpen, Markus; Meyer, Hermann; Beer, Martin; Hoffmann, Donata

2017-01-01

Cowpox virus (CPXV) was considered as uniform species within the genus Orthopoxvirus (OPV). Previous phylogenetic analysis indicated that CPXV is polyphyletic and isolates may cluster into different clades with two of these clades showing genetic similarities to either variola (VARV) or vaccinia viruses (VACV). Further analyses were initiated to assess both the genetic diversity and the evolutionary background of circulating CPXVs. Here we report the full-length sequences of 20 CPXV strains isolated from different animal species and humans in Germany. A phylogenetic analysis of altogether 83 full-length OPV genomes confirmed the polyphyletic character of the species CPXV and suggested at least four different clades. The German isolates from this study mainly clustered into two CPXV-like clades, and VARV- and VACV-like strains were not observed. A single strain, isolated from a cotton-top tamarin, clustered distantly from all other CPXVs and might represent a novel and unique evolutionary lineage. The classification of CPXV strains into clades roughly followed their geographic origin, with the highest clade diversity so far observed for Germany. Furthermore, we found evidence for recombination between OPV clades without significant disruption of the observed clustering. In conclusion, this analysis markedly expands the number of available CPXV full-length sequences and confirms the co-circulation of several CPXV clades in Germany, and provides the first data about a new evolutionary CPXV lineage. PMID:28604604

On the design of paleoenvironmental data networks for estimating large-scale patterns of climate

NASA Astrophysics Data System (ADS)

Kutzbach, J. E.; Guetter, P. J.

1980-09-01

Guidelines are determined for the spatial density and location of climatic variables (temperature and precipitation) that are appropriate for estimating the continental- to hemispheric-scale pattern of atmospheric circulation (sea-level pressure). Because instrumental records of temperature and precipitation simulate the climatic information that is contained in certain paleoenvironmental records (tree-ring, pollen, and written-documentary records, for example), these guidelines provide useful sampling strategies for reconstructing the pattern of atmospheric circulation from paleoenvironmental records. The statistical analysis uses a multiple linear regression model. The sampling strategies consist of changes in site density (from 0.5 to 2.5 sites per million square kilometers) and site location (from western North American sites only to sites in Japan, North America, and western Europe) of the climatic data. The results showed that the accuracy of specification of the pattern of sea-level pressure: (1) is improved if sites with climatic records are spread as uniformly as possible over the area of interest; (2) increases with increasing site density-at least up to the maximum site density used in this study; (3) is improved if sites cover an area that extends considerably beyond the limits of the area of interest. The accuracy of specification was lower for independent data than for the data that were used to develop the regression model; some skill was found for almost all sampling strategies.

Three-axis acoustic device for levitation of droplets in an open gas stream and its application to examine sulfur dioxide absorption by water droplets.

PubMed

Stephens, Terrance L; Budwig, Ralph S

2007-01-01

Two acoustic devices to stabilize a droplet in an open gas stream (single-axis and three-axis levitators) have been designed and tested. The gas stream was provided by a jet apparatus with a 64 mm exit diameter and a uniform velocity profile. The acoustic source used was a Langevin vibrator with a concave reflector. The single-axis levitator relied primarily on the radial force from the acoustic field and was shown to be limited because of significant droplet wandering. The three-axis levitator relied on a combination of the axial and radial forces. The three-axis levitator was applied to examine droplet deformation and circulation and to investigate the uptake of SO(2) from the gas stream to the droplet. Droplets ranging in diameters from 2 to 5 mm were levitated in gas streams with velocities up to 9 ms. Droplet wandering was on the order of a half droplet diameter for a 3 mm diameter droplet. Droplet circulation ranged from the predicted Hadamard-Rybczynski pattern to a rotating droplet pattern. Droplet pH over a central volume of the droplet was measured by planar laser induced fluorescence. The results for the decay of droplet pH versus time are in general agreement with published theory and experiments.

Factors Affecting the Latitudinal Location of the Intertropical Convergence Zone in a GCM

NASA Technical Reports Server (NTRS)

Chao, Winston C.; Chen, Baode

2002-01-01

The dominant role of the latitudinal peak of the sea surface temperature (SST) in determining the latitudinal location of the intertropical convergence zone (ITCZ) is well-known. However, the roles of the other factors are less well-known and are the topic of this study. These other factors include the inertial stability, the interaction between convection and surface fluxes and the interaction between convection and radiation. Since these interactions involve convection, in a model they involve the cumulus parameterization scheme. These factors are studied with a general circulation model with uniform SST and solar angle. Under the aforementioned model settings, the latitudinal location of the ITCZ is the latitude where the balance of two types of attraction on the ITCZ, both due to earth's rotation, exists. Directly related to the Coriolis parameter, the first type pulls the ITCZ toward the equator and is not sensitive to model design changes. Related to the convective circulation, the second type pulls the ITCZ poleward and is sensitive to model design changes. Due to the shape and the magnitude of the attractors, the balance of the two types of attractions is reached either at the equator or more than 10 degrees away from the equator. The former case results in a single ITCZ over the equator and the latter case a double ITCZ straddling the equator.

Three-axis acoustic device for levitation of droplets in an open gas stream and its application to examine sulfur dioxide absorption by water droplets

NASA Astrophysics Data System (ADS)

Stephens, Terrance L.; Budwig, Ralph S.

2007-01-01

Two acoustic devices to stabilize a droplet in an open gas stream (single-axis and three-axis levitators) have been designed and tested. The gas stream was provided by a jet apparatus with a 64mm exit diameter and a uniform velocity profile. The acoustic source used was a Langevin vibrator with a concave reflector. The single-axis levitator relied primarily on the radial force from the acoustic field and was shown to be limited because of significant droplet wandering. The three-axis levitator relied on a combination of the axial and radial forces. The three-axis levitator was applied to examine droplet deformation and circulation and to investigate the uptake of SO2 from the gas stream to the droplet. Droplets ranging in diameters from 2to5mm were levitated in gas streams with velocities up to 9m /s. Droplet wandering was on the order of a half droplet diameter for a 3mm diameter droplet. Droplet circulation ranged from the predicted Hadamard-Rybczynski pattern to a rotating droplet pattern. Droplet pH over a central volume of the droplet was measured by planar laser induced fluorescence. The results for the decay of droplet pH versus time are in general agreement with published theory and experiments.

Transient detection of Chlamydial-specific Th1 memory cells in the peripheral circulation of women with history of Chlamydia trachomatis genital tract infection.

PubMed

Vicetti Miguel, Rodolfo D; Reighard, Seth D; Chavez, Jean M; Rabe, Lorna K; Maryak, Samantha A; Wiesenfeld, Harold C; Cherpes, Thomas L

2012-12-01

Development of safe and effective Chlamydia trachomatis vaccines requires better understanding of the host immune responses elicited by natural infection. Peripheral blood mononuclear cells isolated from women with or without history of genital tract chlamydial infection were stimulated with inactivated C. trachomatis elementary bodies (EB) in ELISPOT assays that enumerated frequencies of cells producing interferon (IFN)-γ or interleukin (IL)-17. IFN-γ-positive cells were highest among women sampled 30-60 days after diagnosis of C. trachomatis infection and treatment initiation, while the numbers of IFN-γ-positive cells were equally low among uninfected women and women sampled <30 or >60 days after diagnosis of infection. Conversely, IL-17-positive cell numbers were uniformly low among all participants. Dramatically reduced numbers of Chlamydia-specific Th1 memory cells in the peripheral circulation of study participants sampled more than 2 months after diagnosis, and initiation of treatment provides new insight into the results from C. trachomatis vaccine trials, in which immunization with EB provided only short-lived protection. Our results also suggest that an effective vaccine against this weakly antigenic intracellular pathogen will need to generate immunological memory more durable than that elicited by natural infection. © 2012 John Wiley & Sons A/S.

Aneurysm flow characteristics in realistic carotid artery aneurysm models induced by proximal virtual stenotic plaques: a computational hemodynamics study

NASA Astrophysics Data System (ADS)

Castro, Marcelo A.; Peloc, Nora L.; Chien, Aichi; Goldberg, Ezequiel; Putman, Christopher M.; Cebral, Juan R.

2015-03-01

Cerebral aneurysms may rarely coexist with a proximal artery stenosis. In that small percent of patients, such coexistence poses a challenge for interventional neuroradiologists and neurosurgeons to make the best treatment decision. According to previous studies, the incidence of cerebral aneurysms in patients with internal carotid artery stenosis is no greater than five percent, where the aneurysm is usually incidentally detected, being about two percent for aneurysms and stenoses in the same cerebral circulation. Those cases pose a difficult management decision for the physician. Case reports showed patients who died due to aneurysm rupture months after endarterectomy but before aneurysm clipping, while others did not show any change in the aneurysm after plaque removal, having optimum outcome after aneurysm coiling. The aim of this study is to investigate the intra-aneurysmal hemodynamic changes before and after treatment of stenotic plaque. Virtually created moderate stenoses in vascular models of internal carotid artery aneurysm patients were considered in a number of cases reconstructed from three dimensional rotational angiography images. The strategy to create those plaques was based on parameters analyzed in a previous work where idealized models were considered, including relative distance and stenosis grade. Ipsilateral and contralateral plaques were modeled. Wall shear stress and velocity pattern were computed from finite element pulsatile blood flow simulations. The results may suggest that wall shear stress changes depend on relative angular position between the aneurysm and the plaque.

The influence of chromatic context on binocular color rivalry: Perception and neural representation

PubMed Central

Hong, Sang Wook; Shevell, Steven K.

2008-01-01

The predominance of rivalrous targets is affected by surrounding context when stimuli rival in orientation, motion or color. This study investigated the influence of chromatic context on binocular color rivalry. The predominance of rivalrous chromatic targets was measured in various surrounding contexts. The first experiment showed that a chromatic surround's influence was stronger when the surround was uniform or a grating with luminance contrast (chromatic/black grating) compared to an equiluminant grating (chromatic/white). The second experiment revealed virtually no effect of the orientation of the surrounding chromatic context, using chromatically rivalrous vertical gratings. These results are consistent with a chromatic representation of the context by a non-oriented, chromatically selective and spatially antagonistic receptive field. Neither a double-opponent receptive field nor a receptive field without spatial antagonism accounts for the influence of context on binocular color rivalry. PMID:18331750

Epistemologies, deafness, learning, and teaching.

PubMed

Moores, Donald F

2010-01-01

The study of Deaf epistemologies is in a nascent stage relative to, e.g., the study of feminist or African American epistemologies. It has only recently begun attracting the widespread attention it deserves. The present article addresses Deaf epistemologies as they relate to the sometimes conflicting trends in American society and education. In a relatively short period, the education of deaf students has gone from an independent enterprise under the aegis of special education to heavy influence by No Child Left Behind legislation that applies to virtually all American students. American education at one and the same time embraces and celebrates diversity, imposes uniform, rigid learning standards for all children, and mandates that all children be tested in the same way. An oxymoron exists of individualized educational planning and one-size-fits-all curricula and assessment of academic achievement. Implications for teaching and learning of deaf students are explored.

Composite lithium metal anode by melt infusion of lithium into a 3D conducting scaffold with lithiophilic coating

PubMed Central

Liang, Zheng; Lin, Dingchang; Zhao, Jie; Lu, Zhenda; Liu, Yayuan; Liu, Chong; Lu, Yingying; Wang, Haotian; Yan, Kai; Tao, Xinyong; Cui, Yi

2016-01-01

Lithium metal-based battery is considered one of the best energy storage systems due to its high theoretical capacity and lowest anode potential of all. However, dendritic growth and virtually relative infinity volume change during long-term cycling often lead to severe safety hazards and catastrophic failure. Here, a stable lithium–scaffold composite electrode is developed by lithium melt infusion into a 3D porous carbon matrix with “lithiophilic” coating. Lithium is uniformly entrapped on the matrix surface and in the 3D structure. The resulting composite electrode possesses a high conductive surface area and excellent structural stability upon galvanostatic cycling. We showed stable cycling of this composite electrode with small Li plating/stripping overpotential (<90 mV) at a high current density of 3 mA/cm2 over 80 cycles. PMID:26929378

Wide range radioactive gas concentration detector

DOEpatents

Anderson, David F.

1984-01-01

A wide range radioactive gas concentration detector and monitor which is capable of measuring radioactive gas concentrations over a range of eight orders of magnitude. The device of the present invention is designed to have an ionization chamber which is sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.

Specific binding of sup 125 I-rErythropoietin to Friend polycythemia virus-transformed erythroleukemia cells purified by centrifugal elutriation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Correa, P.N.; Bard, V.; Axelrad, A.A.

1990-01-01

We have used countercurrent centrifugal elutriation (CCE) to determine the distribution of cells with respect to cell volume and buoyant density for an erythroleukemia cell line (JG6) transformed by the polycythemia strain of Friend virus (FV-P), and to determine the effect of inducing the cells to differentiate with dimethylsulfoxide (DMSO) on this distribution. CCE made it possible to obtain suspensions of modal JG6 populations virtually free of dead cells and uniform with respect to volume and buoyant density. These modal populations were assayed for specific binding of erythropoietin (Epo). Between 500 and 550 Epo receptors per cell were detected. Thesemore » belonged to a single class having a dissociation constant of 0.36 nM. DMSO induction of differentiation of the JG6 cells had no effect on the number of Epo receptors expressed.« less

Facile Synthesis of Uniform Virus-like Mesoporous Silica Nanoparticles for Enhanced Cellular Internalization

PubMed Central

2017-01-01

The low-efficiency cellular uptake property of current nanoparticles greatly restricts their application in the biomedical field. Herein, we demonstrate that novel virus-like mesoporous silica nanoparticles can easily be synthesized, showing greatly superior cellular uptake property. The unique virus-like mesoporous silica nanoparticles with a spiky tubular rough surface have been successfully synthesized via a novel single-micelle epitaxial growth approach in a low-concentration-surfactant oil/water biphase system. The virus-like nanoparticles’ rough surface morphology results mainly from the mesoporous silica nanotubes spontaneously grown via an epitaxial growth process. The obtained nanoparticles show uniform particle size and excellent monodispersity. The structural parameters of the nanoparticles can be well tuned with controllable core diameter (∼60–160 nm), tubular length (∼6–70 nm), and outer diameter (∼6–10 nm). Thanks to the biomimetic morphology, the virus-like nanoparticles show greatly superior cellular uptake property (invading living cells in large quantities within few minutes, <5 min), unique internalization pathways, and extended blood circulation duration (t1/2 = 2.16 h), which is much longer than that of conventional mesoporous silica nanoparticles (0.45 h). Furthermore, our epitaxial growth strategy can be applied to fabricate various virus-like mesoporous core–shell structures, paving the way toward designed synthesis of virus-like nanocomposites for biomedicine applications. PMID:28852697

Horizontal heat fluxes over complex terrain computed using a simple mixed-layer model and a numerical model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimura, Fujio; Kuwagata, Tuneo

1995-02-01

The thermally induced local circulation over a periodic valley is simulated by a two-dimensional numerical model that does-not include condensational processes. During the daytime of a clear, calm day, heat is transported from the mountainous region to the valley area by anabatic wind and its return flow. The specific humidity is, however, transported in an inverse manner. The horizontal exchange rate of sensible heat has a horizontal scale similarity, as long as the horizontal scale is less than a critical width of about 100 km. The sensible heat accumulated in an atmospheric column over an arbitrary point can be estimatedmore » by a simple model termed the uniform mixed-layer model (UML). The model assumes that the potential temperature is both vertically and horizontally uniform in the mixed layer, even over the complex terrain. The UML model is valid only when the horizontal scale of the topography is less than the critical width and the maximum difference in the elevation of the topography is less than about 1500 m. Latent heat is accumulated over the mountainous region while the atmosphere becomes dry over the valley area. When the horizontal scale is close to the critical width, the largest amount of humidity is accumulated during the late afternoon over the mountainous region. 18 refs., 15 figs., 1 tab.« less

An empirical comparison of primary baffle and vanes for optical astronomical telescope

NASA Astrophysics Data System (ADS)

Li, Taoran; Chen, Yingwei

2017-09-01

In optical astronomical telescopes, the primary baffle is a tube-like structure centering in the hole of the primary mirror and the vanes usually locate inside the baffle, improving the suppression of stray light. They are the most common methods of stray light control. To characterize the performance of primary baffle and vanes, an empirical comparison based on astronomical observations has been made with Xinglong 50cm telescope. Considering the convenience of switching, an independent vanes structure is designed, which can also improve the process of the primary mirror cooling and the air circulation. The comparison of two cases: (1) primary baffle plus vanes and (2) vanes alone involves in-dome and on-sky observations. Both the single star and the various off-axis angles of the stray light source observations are presented. The photometrical images are recorded by CCD to analyze the magnitude and the photometric error. The stray light uniformity of the image background derives from the reduction image which utilizes the MATLAB software to remove the stars. The in-dome experiments results reveal the effectiveness of primary baffle and the independent vanes structure. Meanwhile, the on-sky photometric data indicate there are little differences between them. The stray light uniformity has no difference when the angle between the star and the moon is greater than 20 degrees.

A near uniform basin-wide sea level fluctuation over the Japan/East Sea: A semienclosed sea with multiple straits

NASA Astrophysics Data System (ADS)

Kim, Seung-Bum; Fukumori, Ichiro

2008-06-01

Sea level of the Japan/East Sea observed by the TOPEX/Poseidon (T/P) satellite altimeter is analyzed using a 1/4°-resolution ocean general circulation model. A significant fraction of the Japan/East Sea sea level variability is found to be spatially uniform with periods ranging from 20 d to a year. The model simulation is consistent with T/P records in terms of the basin-wide sea level fluctuation's spectral energy and coherence. The simulation indicates that the changes are barotropic in nature and controlled, notably at high frequencies, by the net mass transport through the straits of the Japan/East Sea driven by winds in the vicinity of the Korea/Tsushima and Soya Straits. A series of barotropic simulations suggest that the sea level fluctuations are the result of a dynamic balance at the straits among near-strait winds, friction, and geostrophic control. The basin-wide sea level response is a linear superposition of changes due to winds near the individual straits. In particular, a basin-wide sea level response can be established by winds near either one of the straits alone. For the specific geometry and winds, winds near the Soya Strait have a larger impact on the Japan/East Sea mean sea level than those near the Korea/Tsushima Strait.

Single and Double ITCZ in Aqua-Planet Models with Globally Uniform Sea Surface Temperature and Solar Insolation: An Interpretation

NASA Technical Reports Server (NTRS)

Chao, Winston C.; Chen, Baode; Einaudi, Franco (Technical Monitor)

2001-01-01

It has been known for more than a decade that an aqua-planet model with globally uniform sea surface temperature and solar insolation angle can generate ITCZ (intertropical convergence zone). Previous studies have shown that the ITCZ under such model settings can be changed between a single ITCZ over the equator and a double ITCZ straddling the equator through one of several measures. These measures include switching to a different cumulus parameterization scheme, changes within the cumulus parameterization scheme, and changes in other aspects of the model design such as horizontal resolution. In this paper an interpretation for these findings is offered. The latitudinal location of the ITCZ is the latitude where the balance of two types of attraction on the ITCZ, both due to earth's rotation, exists. The first type is equator-ward and is directly related to the earth's rotation and thus not sensitive to model design changes. The second type is poleward and is related to the convective circulation and thus is sensitive to model design changes. Due to the shape of the attractors, the balance of the two types of attractions is reached either at the equator or more than 10 degrees away from the equator. The former case results in a single ITCZ over the equator and the latter case a double ITCZ straddling the equator.

Regional paleofire regimes affected by non-uniform climate, vegetation and human drivers

PubMed Central

Blarquez, Olivier; Ali, Adam A.; Girardin, Martin P.; Grondin, Pierre; Fréchette, Bianca; Bergeron, Yves; Hély, Christelle

2015-01-01

Climate, vegetation and humans act on biomass burning at different spatial and temporal scales. In this study, we used a dense network of sedimentary charcoal records from eastern Canada to reconstruct regional biomass burning history over the last 7000 years at the scale of four potential vegetation types: open coniferous forest/tundra, boreal coniferous forest, boreal mixedwood forest and temperate forest. The biomass burning trajectories were compared with regional climate trends reconstructed from general circulation models, tree biomass reconstructed from pollen series, and human population densities. We found that non-uniform climate, vegetation and human drivers acted on regional biomass burning history. In the open coniferous forest/tundra and dense coniferous forest, the regional biomass burning was primarily shaped by gradual establishment of less climate-conducive burning conditions over 5000 years. In the mixed boreal forest an increasing relative proportion of flammable conifers in landscapes since 2000 BP contributed to maintaining biomass burning constant despite climatic conditions less favourable to fires. In the temperate forest, biomass burning was uncoupled with climatic conditions and the main driver was seemingly vegetation until European colonization, i.e. 300 BP. Tree biomass and thus fuel accumulation modulated fire activity, an indication that biomass burning is fuel-dependent and notably upon long-term co-dominance shifts between conifers and broadleaf trees. PMID:26330162

Quantitation of fetal DNA fraction in maternal plasma using circulating single molecule amplification and re-sequencing technology (cSMART).

PubMed

Song, Yijun; Zhou, Xiya; Huang, Saiqiong; Li, Xiaohong; Qi, Qingwei; Jiang, Yulin; Liu, Yiqian; Ma, Chengcheng; Li, Zhifeng; Xu, Mengnan; Cram, David S; Liu, Juntao

2016-05-01

Calculation of the fetal DNA fraction (FF) is important for reliable and accurate noninvasive prenatal testing (NIPT) for fetal genetic abnormalities. The aim of the study was to develop and validate a novel method for FF determination. FF was calculated using the chromosome Y (ChrY) sequence read assay and by circulating single molecule amplification and re-sequencing technology of 76 autosomal SNPs. By Pearson correlation for FF (4.73-22.11%) in 33 male pregnancy samples, the R(2) co-efficient for the 76-SNP versus the ChrY assay was 0.9572 (p<0.001). In addition, the co-efficient of variation (CV) of FF measurement by the 76-SNP assay was low (0.15-0.35). As a control, the FF measurement for four non-pregnant plasma samples was virtually zero. In prospective longitudinal studies of 14 women with normal pregnancies, FF generally increased with gestational age. However, in eight women (71%) there was a significant decrease in FF between the first trimester (11-13 weeks) and the second trimester (15-19 weeks), and this was attributable to significant maternal weight gain. The novel 76-SNP cSMART assay has the precision to accurately measure FF in all pregnancies at a detection threshold of 5%. Based on FF trends in individual pregnancies, our results suggest that the end of the first trimester may be a more optimal window for performing NIPT. Copyright © 2016 Elsevier B.V. All rights reserved.

A scalable multi-DLP pico-projector system for virtual reality

NASA Astrophysics Data System (ADS)

Teubl, F.; Kurashima, C.; Cabral, M.; Fels, S.; Lopes, R.; Zuffo, M.

2014-03-01

Virtual Reality (VR) environments can offer immersion, interaction and realistic images to users. A VR system is usually expensive and requires special equipment in a complex setup. One approach is to use Commodity-Off-The-Shelf (COTS) desktop multi-projectors manually or camera based calibrated to reduce the cost of VR systems without significant decrease of the visual experience. Additionally, for non-planar screen shapes, special optics such as lenses and mirrors are required thus increasing costs. We propose a low-cost, scalable, flexible and mobile solution that allows building complex VR systems that projects images onto a variety of arbitrary surfaces such as planar, cylindrical and spherical surfaces. This approach combines three key aspects: 1) clusters of DLP-picoprojectors to provide homogeneous and continuous pixel density upon arbitrary surfaces without additional optics; 2) LED lighting technology for energy efficiency and light control; 3) smaller physical footprint for flexibility purposes. Therefore, the proposed system is scalable in terms of pixel density, energy and physical space. To achieve these goals, we developed a multi-projector software library called FastFusion that calibrates all projectors in a uniform image that is presented to viewers. FastFusion uses a camera to automatically calibrate geometric and photometric correction of projected images from ad-hoc positioned projectors, the only requirement is some few pixels overlapping amongst them. We present results with eight Pico-projectors, with 7 lumens (LED) and DLP 0.17 HVGA Chipset.

Algorithm design for a gun simulator based on image processing

NASA Astrophysics Data System (ADS)

Liu, Yu; Wei, Ping; Ke, Jun

2015-08-01

In this paper, an algorithm is designed for shooting games under strong background light. Six LEDs are uniformly distributed on the edge of a game machine screen. They are located at the four corners and in the middle of the top and the bottom edges. Three LEDs are enlightened in the odd frames, and the other three are enlightened in the even frames. A simulator is furnished with one camera, which is used to obtain the image of the LEDs by applying inter-frame difference between the even and odd frames. In the resulting images, six LED are six bright spots. To obtain the LEDs' coordinates rapidly, we proposed a method based on the area of the bright spots. After calibrating the camera based on a pinhole model, four equations can be found using the relationship between the image coordinate system and the world coordinate system with perspective transformation. The center point of the image of LEDs is supposed to be at the virtual shooting point. The perspective transformation matrix is applied to the coordinate of the center point. Then we can obtain the virtual shooting point's coordinate in the world coordinate system. When a game player shoots a target about two meters away, using the method discussed in this paper, the calculated coordinate error is less than ten mm. We can obtain 65 coordinate results per second, which meets the requirement of a real-time system. It proves the algorithm is reliable and effective.

Freeform étendue-preserving optics for light and color mixing

NASA Astrophysics Data System (ADS)

Sorgato, Simone; Mohedano, Rubén.; Chaves, Julio; Cvetkovic, Aleksandra; Hernández, Maikel; Benítez, Pablo; Miñano, Juan C.; Thienpont, Hugo; Duerr, Fabian

2015-09-01

Today's SSL illumination market shows a clear trend towards high flux packages with higher efficiency and higher CRI, realized by means of multiple color chips and phosphors. Such light sources require the optics to provide both near- and far-field color mixing. This design problem is particularly challenging for collimated luminaries, since traditional diffusers cannot be employed without enlarging the exit aperture and reducing brightness (so increasing étendue). Furthermore, diffusers compromise the light output ratio (efficiency) of the lamps to which they are applied. A solution, based on Köhler integration, consisting of a spherical cap comprising spherical microlenses on both its interior and exterior sides was presented in 2012. When placed on top of an inhomogeneous multichip Lambertian LED, this so-called Shell-Mixer creates a homogeneous (both spatially and angularly) virtual source, also Lambertian, where the images of the chips merge. The virtual source is located at the same position with essentially the same size of the original source. The diameter of this optics was 3 times that of the chip-array footprint. In this work, we present a new version of the Shell-Mixer, based on the Edge Ray Principle, where neither the overall shape of the cap nor the surfaces of the lenses are constrained to spheres or rotational Cartesian ovals. This new Shell- Mixer is freeform, only twice as large as the original chip-array and equals the original model in terms of brightness, color uniformity and efficiency.

Virtual Learning Environment in Continuing Education for Nursing in Oncology: an Experimental Study.

PubMed

das Graças Silva Matsubara, Maria; De Domenico, Edvane Birelo Lopes

2016-12-01

Nurses working in oncology require continuing education and nowadays distance education is a possibility. To compare learning outcomes of the professionals participating in classroom learning versus distance learning; describing the sociodemographic characteristics and digital fluency of participants; comparing learning outcomes with independent variables; assessing the adequacy of educational practices in Virtual Environment Moodle Learning through the constructivist online learning environment survey. An experimental, randomized controlled study; conducted at the A C Camargo Cancer Center, located in São Paulo, SP, Brazil. The study included 97 nurses, with average training of 1 to 2 years. A control group (n = 44) had face to face training and the experiment group (n = 53) had training by distance learning, both with identical program content. The dependent variable was the result of learning, measured by applying a pre-assessment questionnaire and post-intervention for both groups. The sociodemographic and digital fluency data were uniform among the groups. The performance of both groups was statistically significant (p 0.005), and the control group had a greater advantage (40.4 %). Distance education has proven to be an effective alternative for training nurses, especially when they have more complex knowledge, more experience in the area and institutional time. Distance Education may be a possibility for the training of nurses for work in oncology. The association of age, training time and the institution, and the experience in Oncology interfered in the performance of both groups.

An Accurate Direction Finding Scheme Using Virtual Antenna Array via Smartphones.

PubMed

Wang, Xiaopu; Xiong, Yan; Huang, Wenchao

2016-10-29

With the development of localization technologies, researchers solve the indoor localization problems using diverse methods and equipment. Most localization techniques require either specialized devices or fingerprints, which are inconvenient for daily use. Therefore, we propose and implement an accurate, efficient and lightweight system for indoor direction finding using common smartphones and loudspeakers. Our method is derived from a key insight: By moving a smartphone in regular patterns, we can effectively emulate the sensitivity and functionality of a Uniform Antenna Array to estimate the angle of arrival of the target signal. Specifically, a user only needs to hold his smartphone still in front of him, and then rotate his body around 360 ∘ duration with the smartphone at an approximate constant velocity. Then, our system can provide accurate directional guidance and lead the user to their destinations (normal loudspeakers we preset in the indoor environment transmitting high frequency acoustic signals) after a few measurements. Major challenges in implementing our system are not only imitating a virtual antenna array by ordinary smartphones but also overcoming the detection difficulties caused by the complex indoor environment. In addition, we leverage the gyroscope of the smartphone to reduce the impact of a user's motion pattern change to the accuracy of our system. In order to get rid of the multipath effect, we leverage multiple signal classification to calculate the direction of the target signal, and then design and deploy our system in various indoor scenes. Extensive comparative experiments show that our system is reliable under various circumstances.

Final Scientific/Technical Report for "Enabling Exascale Hardware and Software Design through Scalable System Virtualization"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dinda, Peter August

2015-03-17

This report describes the activities, findings, and products of the Northwestern University component of the "Enabling Exascale Hardware and Software Design through Scalable System Virtualization" project. The purpose of this project has been to extend the state of the art of systems software for high-end computing (HEC) platforms, and to use systems software to better enable the evaluation of potential future HEC platforms, for example exascale platforms. Such platforms, and their systems software, have the goal of providing scientific computation at new scales, thus enabling new research in the physical sciences and engineering. Over time, the innovations in systems softwaremore » for such platforms also become applicable to more widely used computing clusters, data centers, and clouds. This was a five-institution project, centered on the Palacios virtual machine monitor (VMM) systems software, a project begun at Northwestern, and originally developed in a previous collaboration between Northwestern University and the University of New Mexico. In this project, Northwestern (including via our subcontract to the University of Pittsburgh) contributed to the continued development of Palacios, along with other team members. We took the leadership role in (1) continued extension of support for emerging Intel and AMD hardware, (2) integration and performance enhancement of overlay networking, (3) connectivity with architectural simulation, (4) binary translation, and (5) support for modern Non-Uniform Memory Access (NUMA) hosts and guests. We also took a supporting role in support for specialized hardware for I/O virtualization, profiling, configurability, and integration with configuration tools. The efforts we led (1-5) were largely successful and executed as expected, with code and papers resulting from them. The project demonstrated the feasibility of a virtualization layer for HEC computing, similar to such layers for cloud or datacenter computing. For effort (3), although a prototype connecting Palacios with the GEM5 architectural simulator was demonstrated, our conclusion was that such a platform was less useful for design space exploration than anticipated due to inherent complexity of the connection between the instruction set architecture level and the microarchitectural level. For effort (4), we found that a code injection approach proved to be more fruitful. The results of our efforts are publicly available in the open source Palacios codebase and published papers, all of which are available from the project web site, v3vee.org. Palacios is currently one of the two codebases (the other being Sandia’s Kitten lightweight kernel) that underlies the node operating system for the DOE Hobbes Project, one of two projects tasked with building a systems software prototype for the national exascale computing effort.« less

Scenario Based Approach for Multiple Source Tsunami Hazard Assessment for Sines, Portugal

NASA Astrophysics Data System (ADS)

Wronna, Martin; Omira, Rachid; Baptista, Maria Ana

2015-04-01

In this paper, we present a scenario-based approach for tsunami hazard assessment for the city and harbour of Sines, Portugal one the test-sites of project ASTARTE. Sines holds one of the most important deep-water ports which contains oil-bearing, petrochemical, liquid bulk, coal and container terminals. The port and its industrial infrastructures are facing the ocean to the southwest facing the main seismogenic sources. This work considers two different seismic zones: the Southwest Iberian Margin and the Gloria Fault. Within these two regions, a total of five scenarios were selected to assess tsunami impact at the test site. These scenarios correspond to the worst-case credible scenario approach based upon the largest events of the historical and paleo tsunami catalogues. The tsunami simulations from the source area towards the coast is carried out using NSWING a Non-linear Shallow Water Model With Nested Grids. The code solves the non-linear shallow water equations using the discretization and explicit leap-frog finite difference scheme, in a Cartesian or Spherical frame. The initial sea surface displacement is assumed to be equal to the sea bottom deformation that is computed by Okada equations. Both uniform and non-uniform slip conditions are used. The presented results correspond to the models using non-uniform slip conditions. In this study, the static effect of tides is analysed for three different tidal stages MLLW (mean lower low water) MSL (mean sea level) and MHHW (mean higher high water). For each scenario, inundation is described by maximum values of wave height, flow depth, drawdown, run-up and inundation distance. Synthetic waveforms are computed at virtual tide gages at specific locations outside and inside the harbour. The final results consist of Aggregate Scenario Maps presented for the different inundation parameters. This work is funded by ASTARTE - Assessment, Strategy And Risk Reduction for Tsunamis in Europe - FP7-ENV2013 6.4-3, Grant 603839

Charge-Spot Model for Electrostatic Forces in Simulation of Fine Particulates

NASA Technical Reports Server (NTRS)

Walton, Otis R.; Johnson, Scott M.

2010-01-01

The charge-spot technique for modeling the static electric forces acting between charged fine particles entails treating electric charges on individual particles as small sets of discrete point charges, located near their surfaces. This is in contrast to existing models, which assume a single charge per particle. The charge-spot technique more accurately describes the forces, torques, and moments that act on triboelectrically charged particles, especially image-charge forces acting near conducting surfaces. The discrete element method (DEM) simulation uses a truncation range to limit the number of near-neighbor charge spots via a shifted and truncated potential Coulomb interaction. The model can be readily adapted to account for induced dipoles in uncharged particles (and thus dielectrophoretic forces) by allowing two charge spots of opposite signs to be created in response to an external electric field. To account for virtual overlap during contacts, the model can be set to automatically scale down the effective charge in proportion to the amount of virtual overlap of the charge spots. This can be accomplished by mimicking the behavior of two real overlapping spherical charge clouds, or with other approximate forms. The charge-spot method much more closely resembles real non-uniform surface charge distributions that result from tribocharging than simpler approaches, which just assign a single total charge to a particle. With the charge-spot model, a single particle may have a zero net charge, but still have both positive and negative charge spots, which could produce substantial forces on the particle when it is close to other charges, when it is in an external electric field, or when near a conducting surface. Since the charge-spot model can contain any number of charges per particle, can be used with only one or two charge spots per particle for simulating charging from solar wind bombardment, or with several charge spots for simulating triboelectric charging. Adhesive image-charge forces acting on charged particles touching conducting surfaces can be up to 50 times stronger if the charge is located in discrete spots on the particle surface instead of being distributed uniformly over the surface of the particle, as is assumed by most other models. Besides being useful in modeling particulates in space and distant objects, this modeling technique is useful for electrophotography (used in copiers) and in simulating the effects of static charge in the pulmonary delivery of fine dry powders.

Seabed topography beneath Larsen C Ice Shelf from seismic soundings

NASA Astrophysics Data System (ADS)

Brisbourne, A. M.; Smith, A. M.; King, E. C.; Nicholls, K. W.; Holland, P. R.; Makinson, K.

2014-01-01

Seismic reflection soundings of ice thickness and seabed depth were acquired on the Larsen C Ice Shelf in order to test a sub-ice shelf bathymetry model derived from the inversion of IceBridge gravity data. A series of lines was collected, from the Churchill Peninsula in the north to the Joerg Peninsula in the south, and also towards the ice front. Sites were selected using the bathymetry model derived from the inversion of free-air gravity data to indicate key regions where sub-ice shelf oceanic circulation may be affected by ice draft and seabed depth. The seismic velocity profile in the upper 100 m of firn and ice was derived from shallow refraction surveys at a number of locations. Measured temperatures within the ice column and at the ice base were used to define the velocity profile through the remainder of the ice column. Seismic velocities in the water column were derived from previous in situ measurements. Uncertainties in ice and water cavity thickness are in general < 10 m. Compared with the seismic measurements, the root-mean-square error in the gravimetrically derived bathymetry at the seismic sites is 162 m. The seismic profiles prove the non-existence of several bathymetric features that are indicated in the gravity inversion model, significantly modifying the expected oceanic circulation beneath the ice shelf. Similar features have previously been shown to be highly significant in affecting basal melt rates predicted by ocean models. The discrepancies between the gravity inversion results and the seismic bathymetry are attributed to the assumption of uniform geology inherent in the gravity inversion process and also the sparsity of IceBridge flight lines. Results indicate that care must be taken when using bathymetry models derived by the inversion of free-air gravity anomalies. The bathymetry results presented here will be used to improve existing sub-ice shelf ocean circulation models.

Seabed topography beneath Larsen C Ice Shelf from seismic soundings

NASA Astrophysics Data System (ADS)

Brisbourne, A. M.; Smith, A. M.; King, E. C.; Nicholls, K. W.; Holland, P. R.; Makinson, K.

2013-08-01

Seismic reflection soundings of ice thickness and seabed depth were acquired on the Larsen C Ice Shelf in order to test a sub-shelf bathymetry model derived from the inversion of IceBridge gravity data. A series of lines were collected, from the Churchill Peninsula in the north to the Joerg Peninsula in the south, and also towards the ice front. Sites were selected using the bathymetry model derived from the inversion of free-air gravity data to indicate key regions where sub-shelf oceanic circulation may be affected by ice draft and sub-shelf cavity thickness. The seismic velocity profile in the upper 100 m of firn and ice was derived from shallow refraction surveys at a number of locations. Measured temperatures within the ice column and at the ice base were used to define the velocity profile through the remainder of the ice column. Seismic velocities in the water column were derived from previous in situ measurements. Uncertainties in ice and water cavity thickness are in general <10 m. Compared with the seismic measurements, the root-mean-square error in the gravimetrically derived bathymetry at the seismic sites is 162 m. The seismic profiles prove the non-existence of several bathymetric features that are indicated in the gravity inversion model, significantly modifying the expected oceanic circulation beneath the ice shelf. Similar features have previously been shown to be highly significant in affecting basal melt rates predicted by ocean models. The discrepancies between the gravity inversion results and the seismic bathymetry are attributed to the assumption of uniform geology inherent in the gravity inversion process and also the sparsity of IceBridge flight lines. Results indicate that care must be taken when using bathymetry models derived by the inversion of free-air gravity anomalies. The bathymetry results presented here will be used to improve existing sub-shelf ocean circulation models.

Kinematic and diabatic vertical velocity climatologies from a chemistry climate model

NASA Astrophysics Data System (ADS)

Marinke Hoppe, Charlotte; Ploeger, Felix; Konopka, Paul; Müller, Rolf

2016-05-01

The representation of vertical velocity in chemistry climate models is a key element for the representation of the large-scale Brewer-Dobson circulation in the stratosphere. Here, we diagnose and compare the kinematic and diabatic vertical velocities in the ECHAM/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model. The calculation of kinematic vertical velocity is based on the continuity equation, whereas diabatic vertical velocity is computed using diabatic heating rates. Annual and monthly zonal mean climatologies of vertical velocity from a 10-year simulation are provided for both kinematic and diabatic vertical velocity representations. In general, both vertical velocity patterns show the main features of the stratospheric circulation, namely, upwelling at low latitudes and downwelling at high latitudes. The main difference in the vertical velocity pattern is a more uniform structure for diabatic and a noisier structure for kinematic vertical velocity. Diabatic vertical velocities show higher absolute values both in the upwelling branch in the inner tropics and in the downwelling regions in the polar vortices. Further, there is a latitudinal shift of the tropical upwelling branch in boreal summer between the two vertical velocity representations with the tropical upwelling region in the diabatic representation shifted southward compared to the kinematic case. Furthermore, we present mean age of air climatologies from two transport schemes in EMAC using these different vertical velocities and analyze the impact of residual circulation and mixing processes on the age of air. The age of air distributions show a hemispheric difference pattern in the stratosphere with younger air in the Southern Hemisphere and older air in the Northern Hemisphere using the transport scheme with diabatic vertical velocities. Further, the age of air climatology from the transport scheme using diabatic vertical velocities shows a younger mean age of air in the inner tropical upwelling branch and an older mean age in the extratropical tropopause region.

Right Ventricular Perfusion: Physiology and Clinical Implications.

PubMed

Crystal, George J; Pagel, Paul S

2018-01-01

Regulation of blood flow to the right ventricle differs significantly from that to the left ventricle. The right ventricle develops a lower systolic pressure than the left ventricle, resulting in reduced extravascular compressive forces and myocardial oxygen demand. Right ventricular perfusion has eight major characteristics that distinguish it from left ventricular perfusion: (1) appreciable perfusion throughout the entire cardiac cycle; (2) reduced myocardial oxygen uptake, blood flow, and oxygen extraction; (3) an oxygen extraction reserve that can be recruited to at least partially offset a reduction in coronary blood flow; (4) less effective pressure-flow autoregulation; (5) the ability to downregulate its metabolic demand during coronary hypoperfusion and thereby maintain contractile function and energy stores; (6) a transmurally uniform reduction in myocardial perfusion in the presence of a hemodynamically significant epicardial coronary stenosis; (7) extensive collateral connections from the left coronary circulation; and (8) possible retrograde perfusion from the right ventricular cavity through the Thebesian veins. These differences promote the maintenance of right ventricular oxygen supply-demand balance and provide relative resistance to ischemia-induced contractile dysfunction and infarction, but they may be compromised during acute or chronic increases in right ventricle afterload resulting from pulmonary arterial hypertension. Contractile function of the thin-walled right ventricle is exquisitely sensitive to afterload. Acute increases in pulmonary arterial pressure reduce right ventricular stroke volume and, if sufficiently large and prolonged, result in right ventricular failure. Right ventricular ischemia plays a prominent role in these effects. The risk of right ventricular ischemia is also heightened during chronic elevations in right ventricular afterload because microvascular growth fails to match myocyte hypertrophy and because microvascular dysfunction is present. The right coronary circulation is more sensitive than the left to α-adrenergic-mediated constriction, which may contribute to its greater propensity for coronary vasospasm. This characteristic of the right coronary circulation may increase its vulnerability to coronary vasoconstriction and impaired right ventricular perfusion during administration of α-adrenergic receptor agonists.

Advection of Potential Temperature in the Atmosphere of Irradiated Exoplanets: A Robust Mechanism to Explain Radius Inflation

NASA Technical Reports Server (NTRS)

Tremblin, P.; Chabrier, G.; Mayne, N. J.; Amundsen, D. S.; Baraffe, I.; Debras, F.; Drummond, B.; Manners, J.; Fromang, S.

2017-01-01

The anomalously large radii of strongly irradiated exoplanets have remained a major puzzle in astronomy. Based on a two-dimensional steady-state atmospheric circulation model, the validity of which is assessed by comparison to three-dimensional calculations, we reveal a new mechanism, namely the advection of the potential temperature due to mass and longitudinal momentum conservation, a process occurring in the Earth's atmosphere or oceans. In the deep atmosphere, the vanishing heating flux forces the atmospheric structure to converge to a hotter adiabat than the one obtained with 1D calculations, implying a larger radius for the planet. Not only do the calculations reproduce the observed radius of HD 209458b, but also reproduce the observed correlation between radius inflation and irradiation for transiting planets. Vertical advection of potential temperature induced by non-uniform atmospheric heating thus provides a robust mechanism to explain the inflated radii of irradiated hot Jupiters.

Regional Data Assimilation Using a Stretched-Grid Approach and Ensemble Calculations

NASA Technical Reports Server (NTRS)

Fox-Rabinovitz, M. S.; Takacs, L. L.; Govindaraju, R. C.; Atlas, Robert (Technical Monitor)

2002-01-01

The global variable resolution stretched grid (SG) version of the Goddard Earth Observing System (GEOS) Data Assimilation System (DAS) incorporating the GEOS SG-GCM (Fox-Rabinovitz 2000, Fox-Rabinovitz et al. 2001a,b), has been developed and tested as an efficient tool for producing regional analyses and diagnostics with enhanced mesoscale resolution. The major area of interest with enhanced regional resolution used in different SG-DAS experiments includes a rectangle over the U.S. with 50 or 60 km horizontal resolution. The analyses and diagnostics are produced for all mandatory levels from the surface to 0.2 hPa. The assimilated regional mesoscale products are consistent with global scale circulation characteristics due to using the SG-approach. Both the stretched grid and basic uniform grid DASs use the same amount of global grid-points and are compared in terms of regional product quality.

Influence of orographically steered winds on Mutsu Bay surface currents

NASA Astrophysics Data System (ADS)

Yamaguchi, Satoshi; Kawamura, Hiroshi

2005-09-01

Effects of spatially dependent sea surface wind field on currents in Mutsu Bay, which is located at the northern end of Japanese Honshu Island, are investigated using winds derived from synthetic aperture radar (SAR) images and a numerical model. A characteristic wind pattern over the bay was evidenced from analysis of 118 SAR images and coincided with in situ observations. Wind is topographically steered with easterly winds entering the bay through the terrestrial gap and stronger wind blowing over the central water toward its mouth. Nearshore winds are weaker due to terrestrial blockages. Using the Princeton Ocean Model, we investigated currents forced by the observed spatially dependent wind field. The predicted current pattern agrees well with available observations. For a uniform wind field of equal magnitude and average direction, the circulation pattern departs from observations demonstrating that vorticity input due to spatially dependent wind stress is essential in generation of the wind-driven current in Mutsu Bay.

Pathophysiology, management and treatment of smoke inhalation injury

PubMed Central

Rehberg, Sebastian; Maybauer, Marc O; Enkhbaatar, Perenlei; Maybauer, Dirk M; Yamamoto, Yusuke; Traber, Daniel L

2009-01-01

Smoke inhalation injury continues to increase morbidity and mortality in burn patients in both the third world and industrialized countries. The lack of uniform criteria for the diagnosis and definition of smoke inhalation injury contributes to the fact that, despite extensive research, mortality rates have changed little in recent decades. The formation of reactive oxygen and nitrogen species, as well as the procoagulant and antifibrinolytic imbalance of alveolar homeostasis, all play a central role in the pathogenesis of smoke inhalation injury. Further hallmarks include massive airway obstruction owing to cast formation, bronchospasm, the increase in bronchial circulation and transvascular fluid flux. Therefore, anticoagulants, antioxidants and bronchodilators, especially when administered as an aerosol, represent the most promising treatment strategies. The purpose of this review article is to provide an overview of the pathophysiological changes, management and treatment options of smoke inhalation injury based on the current literature. PMID:20161170

The Flow Field on Hydrofoils with Leading Edge Protuberances

NASA Astrophysics Data System (ADS)

Custodio, Derrick; Henoch, Charles; Johari, Hamid

2009-11-01

The exceptional mobility of the humpback whale has been linked to the use of its unique pectoral flippers. Biologists speculate that the flippers leading edge protuberances are a form of passive flow control. Force measurements on 2D hydrofoils with spanwise uniform leading edge protuberances, resembling those seen on the humpback whale flipper, were taken in a water tunnel and have revealed performance modifications when compared to a baseline NACA 63(4)-021 hydrofoil model. Qualitative flow visualization techniques and Particle Image Velocimetry (PIV) flow field measurements on the modified hydrofoils have shown that streamwise vortices originating from the shoulders of the protuberances are the likely cause of performance changes. Varying levels of interaction among adjacent streamwise vortices have been observed as a function of angle of attack and chord location. The circulation of these vortices as a function of angle of attack and spatial location was measured and an analysis of the vortex interactions will be presented.

Jupiter's Great Red Spot and other vortices

NASA Technical Reports Server (NTRS)

Marcus, Philip S.

1993-01-01

A theoretical explanation of Jupiter's Great Red Spot (GRS) as the self-organization of vorticity in turbulence is presented. A number of properties of the GRS and other Jovian vortices that are unambiguous from the data are listed. The simplest possible model that explains these properties one at a time rather than in a difficult all-encompassing planetary global circulation model is presented. It is shown that Jovian vortices reflect the behavior of quasi-geostrophic (QG) vortices embedded in an east-west wind with bands of uniform potential vorticity. It is argued that most of the properties of the Jovian vortices can be easily explained and understood with QG theory. Many of the signatures of QG vortices are apparent on Voyager images. In numerical and laboratory experiments, QG vortices relax to approximately steady states like the Jovian vortices, rather than oscillating or rotating Kida ellipses.

Experimental parametric study of servers cooling management in data centers buildings

NASA Astrophysics Data System (ADS)

Nada, S. A.; Elfeky, K. E.; Attia, Ali M. A.; Alshaer, W. G.

2017-06-01

A parametric study of air flow and cooling management of data centers servers is experimentally conducted for different design conditions. A physical scale model of data center accommodating one rack of four servers was designed and constructed for testing purposes. Front and rear rack and server's temperatures distributions and supply/return heat indices (SHI/RHI) are used to evaluate data center thermal performance. Experiments were conducted to parametrically study the effects of perforated tiles opening ratio, servers power load variation and rack power density. The results showed that (1) perforated tile of 25% opening ratio provides the best results among the other opening ratios, (2) optimum benefit of cold air in servers cooling is obtained at uniformly power loading of servers (3) increasing power density decrease air re-circulation but increase air bypass and servers temperature. The present results are compared with previous experimental and CFD results and fair agreement was found.

Mechanisms controlling the complete accretionary beach state sequence

NASA Astrophysics Data System (ADS)

Dubarbier, Benjamin; Castelle, Bruno; Ruessink, Gerben; Marieu, Vincent

2017-06-01

Accretionary downstate beach sequence is a key element of observed nearshore morphological variability along sandy coasts. We present and analyze the first numerical simulation of such a sequence using a process-based morphodynamic model that solves the coupling between waves, depth-integrated currents, and sediment transport. The simulation evolves from an alongshore uniform barred beach (storm profile) to an almost featureless shore-welded terrace (summer profile) through the highly alongshore variable detached crescentic bar and transverse bar/rip system states. A global analysis of the full sequence allows determining the varying contributions of the different hydro-sedimentary processes. Sediment transport driven by orbital velocity skewness is critical to the overall onshore sandbar migration, while gravitational downslope sediment transport acts as a damping term inhibiting further channel growth enforced by rip flow circulation. Accurate morphological diffusivity and inclusion of orbital velocity skewness opens new perspectives in terms of morphodynamic modeling of real beaches.

A cross-sectional investigation of the quality of selected medicines in Cambodia in 2010

PubMed Central

2014-01-01

Background Access to good-quality medicines in many countries is largely hindered by the rampant circulation of spurious/falsely labeled/falsified/counterfeit (SFFC) and substandard medicines. In 2006, the Ministry of Health of Cambodia, in collaboration with Kanazawa University, Japan, initiated a project to combat SFFC medicines. Methods To assess the quality of medicines and prevalence of SFFC medicines among selected products, a cross-sectional survey was carried out in Cambodia. Cefixime, omeprazole, co-trimoxazole, clarithromycin, and sildenafil were selected as candidate medicines. These medicines were purchased from private community drug outlets in the capital, Phnom Penh, and Svay Rieng and Kandal provinces through a stratified random sampling scheme in July 2010. Results In total, 325 medicine samples were collected from 111 drug outlets. Non-licensed outlets were more commonly encountered in rural than in urban areas (p < 0.01). Of all the samples, 93.5% were registered and 80% were foreign products. Samples without registration numbers were found more frequently among foreign-manufactured products than in domestic ones (p < 0.01). According to pharmacopeial analytical results, 14.5%, 4.6%, and 24.6% of the samples were unacceptable in quantity, content uniformity, and dissolution test, respectively. All the ultimately unacceptable samples in the content uniformity tests were of foreign origin. Following authenticity investigations conducted with the respective manufacturers and medicine regulatory authorities, an unregistered product of cefixime collected from a pharmacy was confirmed as an SFFC medicine. However, the sample was acceptable in quantity, content uniformity, and dissolution test. Conclusions The results of this survey indicate that medicine counterfeiting is not limited to essential medicines in Cambodia: newer-generation medicines are also targeted. Concerted efforts by both domestic and foreign manufacturers, wholesalers, retailers, and regulatory authorities should help improve the quality of medicines. PMID:24593851

Evaluation of tropical channel refinement using MPAS-A aquaplanet simulations

DOE PAGES

Martini, Matus N.; Gustafson, Jr., William I.; O'Brien, Travis A.; ...

2015-09-13

Climate models with variable-resolution grids offer a computationally less expensive way to provide more detailed information at regional scales and increased accuracy for processes that cannot be resolved by a coarser grid. This study uses the Model for Prediction Across Scales–Atmosphere (MPAS22A), consisting of a nonhydrostatic dynamical core and a subset of Advanced Research Weather Research and Forecasting (ARW-WRF) model atmospheric physics that have been modified to include the Community Atmosphere Model version 5 (CAM5) cloud fraction parameterization, to investigate the potential benefits of using increased resolution in an tropical channel. The simulations are performed with an idealized aquaplanet configurationmore » using two quasi-uniform grids, with 30 km and 240 km grid spacing, and two variable-resolution grids spanning the same grid spacing range; one with a narrow (20°S–20°N) and one with a wide (30°S–30°N) tropical channel refinement. Results show that increasing resolution in the tropics impacts both the tropical and extratropical circulation. Compared to the quasi-uniform coarse grid, the narrow-channel simulation exhibits stronger updrafts in the Ferrel cell as well as in the middle of the upward branch of the Hadley cell. The wider tropical channel has a closer correspondence to the 30 km quasi-uniform simulation. However, the total atmospheric poleward energy transports are similar in all simulations. The largest differences are in the low-level cloudiness. The refined channel simulations show improved tropical and extratropical precipitation relative to the global 240 km simulation when compared to the global 30 km simulation. All simulations have a single ITCZ. Furthermore, the relatively small differences in mean global and tropical precipitation rates among the simulations are a promising result, and the evidence points to the tropical channel being an effective method for avoiding the extraneous numerical artifacts seen in earlier studies that only refined portion of the tropics.« less

Helicity in the atmospheric boundary layer

NASA Astrophysics Data System (ADS)

Kurgansky, Michael; Koprov, Boris; Koprov, Victor; Chkhetiani, Otto

2017-04-01

An overview is presented of recent direct field measurements at the Tsimlyansk Scientific Station of A.M. Obukhov Institute of Atmospheric Physics in Moscow of turbulent helicity (and potential vorticity) using four acoustic anemometers positioned, within the atmospheric surface-adjacent boundary layer, in the vertices of a rectangular tetrahedron, with an approximate 5 m distance between the anemometers and a 5.5 m elevation of the tetrahedron base above the ground surface (Koprov, Koprov, Kurgansky and Chkhetiani. Izvestiya, Atmospheric and Oceanic Physics, 2015, Vol.51, 565-575). The same ideology was applied in a later field experiment in Tsimlyansk with the tetrahedron's size of 0.7 m and variable elevation over the ground from 3.5 to 25 m. It is illustrated with examples of the statistical distribution of instantaneous (both positive and negative) turbulent helicity values. A theory is proposed that explains the measured mean turbulent helicity sign, including the sign of contribution to helicity from the horizontal and vertical velocity & vorticity components, respectively, and the sign of helicity buoyant production term. By considering a superposition of the classic Ekman spiral solution and a jet-like wind profile that mimics a shallow breeze circulation over a non-uniformly heated Earth surface, a possible explanation is provided, why the measured mean turbulent helicity sign is negative. The pronounced breeze circulation over the Tsimlyansk polygon which is located nearby the Tsimlyansk Reservoir was, indeed, observed during the measurements period. Whereas, essentially positive helicity is injected into the boundary layer from the free atmosphere in the Northern Hemisphere.

How do immune cells support and shape the brain in health, disease, and aging?

PubMed

Schwartz, Michal; Kipnis, Jonathan; Rivest, Serge; Prat, Alexandre

2013-11-06

For decades, several axioms have prevailed with respect to the relationships between the CNS and circulating immune cells. Specifically, immune cell entry was largely considered to be pathological or to mark the beginning of pathology within the brain. Moreover, local inflammation associated with neurodegenerative diseases such Alzheimer's disease or amyotrophic lateral sclerosis, were considered similar in their etiology to inflammatory diseases, such as remitting relapsing-multiple sclerosis. The ensuing confusion reflected a lack of awareness that the etiology of the disease as well as the origin of the immune cells determines the nature of the inflammatory response, and that inflammation resolution is an active cellular process. The last two decades have seen a revolution in these prevailing dogmas, with a significant contribution made by the authors. Microglia and infiltrating monocyte-derived macrophages are now known to be functionally distinct and of separate origin. Innate and adaptive immune cells are now known to have protective/healing properties in the CNS, as long as their activity is regulated, and their recruitment is well controlled; their role is appreciated in maintenance of brain plasticity in health, aging, and chronic neurodevelopmental and neurodegenerative diseases. Moreover, it is now understood that the barriers of the brain are not uniform in their interactions with the circulating immune cells. The implications of these new findings to the basic understanding of CNS repair processes, brain aging, and a wide spectrum of CNS disorders, including acute injuries, Rett syndrome, Alzheimer's disease, and multiple sclerosis, will be discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Hang, E-mail: xhinbj@126.com; Li, Mei; Jun, Zhang

Graphical abstract: The micro morphological structure of the nano-TiO{sub 2} particles was also observed with TEM, as shown in figure. The TEM images clearly exhibited the homogeneous microstructure of particles with a size of around 10–15 nm. - Highlights: • Nano-TiO{sub 2} was prepared by complex techniques of sol–gel, micro-emulsion and solvent thermal. • The size of TiO{sub 2} was nano level and uniformity. • Nano-TiO{sub 2} exhibited high photo-catalytic activity at internal air lift circulating reactor. • The best nano-TiO{sub 2} dosage was obtained. - Abstract: Anatase nano-titania (TiO{sub 2}) powder was prepared by using a sol–gel process mediatedmore » in reverse microemulsion combined with a solvent thermal technique. The structures of the obtained TiO{sub 2} were characterized by TG-DSC, XRD, TEM. The photocatalytic decomposition of methylene blue (MB) on nano-TiO{sub 2} was studied by using an internal air lift circulating photocatalytic reactor. The results show that the anatase structure appears in the calcination temperature range of 400–510 °C, while the transformation of anatase into rutile takes place above 510 °C. The homogeneous microstructure of nano-TiO{sub 2} particles was obtained with a size of around 10–15 nm. In the photocatalytic performance, degradation process follows pseudo first order kinetics with different dosages of photocatalyst and initial MB concentrations and optimal TiO{sub 2} dosage is 0.1 g/L with neutral medium.« less

Tracer constraints on organic particle transfer efficiency to the deep ocean

NASA Astrophysics Data System (ADS)

Weber, T. S.; Cram, J. A.; Deutsch, C. A.

2016-02-01

The "transfer efficiency" of sinking organic particles through the mesopelagic zone is a critical determinant of ocean carbon sequestration timescales, and the atmosphere-ocean partition of CO2. Our ability to detect large-scale variations in transfer efficiency is limited by the paucity of particle flux data from the deep ocean, and the potential biases of bottom-moored sediment traps used to collect it. Here we show that deep-ocean particle fluxes can be reconstructed by diagnosing the rate of phosphate accumulation and oxygen disappearance along deep circulation pathways in an observationally constrained Ocean General Circulation Model (OGCM). Combined with satellite and model estimates of carbon export from the surface ocean, these diagnosed fluxes reveal a global pattern of transfer efficiency to 1000m and 2000m that is high ( 20%) at high latitudes and negligible (<5%) throughout subtropical gyres, with intermediate values in the tropics. This pattern is at odds with previous estimates of deep transfer efficiency derived from bottom-moored sediment traps, but is consistent with upper-ocean flux profiles measured by neutrally buoyant sediment traps, which show strong attenuation of low latitude particle fluxes over the top 500m. Mechanistically, the pattern can be explained by spatial variations in particle size distributions, and the temperature-dependence of remineralization. We demonstrate the biogeochemical significance of our findings by comparing estimates of deep-ocean carbon sequestration in a scenario with spatially varying transfer efficiency to one with a globally uniform "Martin-curve" particle flux profile.

The “Silent” Global Burden of Congenital Cytomegalovirus

PubMed Central

Emery, Vincent C.; Lazzarotto, Tiziana; Gupta, Ravindra K.

2013-01-01

Human cytomegalovirus (CMV) is a leading cause of congenital infections worldwide. In the developed world, following the virtual elimination of circulating rubella, it is the commonest nongenetic cause of childhood hearing loss and an important cause of neurodevelopmental delay. The seroprevalence of CMV in adults and the incidence of congenital CMV infection are highest in developing countries (1 to 5% of births) and are most likely driven by nonprimary maternal infections. However, reliable estimates of prevalence and outcome from developing countries are not available. This is largely due to the dogma that maternal preexisting seroimmunity virtually eliminates the risk for sequelae. However, recent data demonstrating similar rates of sequelae, especially hearing loss, following primary and nonprimary maternal infection have underscored the importance of congenital CMV infection in resource-poor settings. Although a significant proportion of congenital CMV infections are attributable to maternal primary infection in well-resourced settings, the absence of specific interventions for seronegative mothers and uncertainty about fetal prognosis have discouraged routine maternal antibody screening. Despite these challenges, encouraging results from prototype vaccines have been reported, and the first randomized phase III trials of prenatal interventions and prolonged postnatal antiviral therapy are under way. Successful implementation of strategies to prevent or reduce the burden of congenital CMV infection will require heightened global awareness among clinicians and the general population. In this review, we highlight the global epidemiology of congenital CMV and the implications of growing knowledge in areas of prevention, diagnosis, prognosis, and management for both low (50 to 70%)- and high (>70%)-seroprevalence settings. PMID:23297260

Plant-Derived Polyphenols in Human Health: Biological Activity, Metabolites and Putative Molecular Targets.

PubMed

Olivares-Vicente, Marilo; Barrajon-Catalan, Enrique; Herranz-Lopez, Maria; Segura-Carretero, Antonio; Joven, Jorge; Encinar, Jose Antonio; Micol, Vicente

2018-01-01

Hibiscus sabdariffa, Lippia citriodora, Rosmarinus officinalis and Olea europaea, are rich in bioactive compounds that represent most of the phenolic compounds' families and have exhibited potential benefits in human health. These plants have been used in folk medicine for their potential therapeutic properties in human chronic diseases. Recent evidence leads to postulate that polyphenols may account for such effects. Nevertheless, the compounds or metabolites that are responsible for reaching the molecular targets are unknown. data based on studies directly using complex extracts on cellular models, without considering metabolic aspects, have limited applicability. In contrast, studies exploring the absorption process, metabolites in the blood circulation and tissues have become essential to identify the intracellular final effectors that are responsible for extracts bioactivity. Once the cellular metabolites are identified using high-resolution mass spectrometry, docking techniques suppose a unique tool for virtually screening a large number of compounds on selected targets in order to elucidate their potential mechanisms. we provide an updated overview of the in vitro and in vivo studies on the toxicity, absorption, permeability, pharmacokinetics and cellular metabolism of bioactive compounds derived from the abovementioned plants to identify the potential compounds that are responsible for the observed health effects. we propose the use of targeted metabolomics followed by in silico studies to virtually screen identified metabolites on selected protein targets, in combination with the use of the candidate metabolites in cellular models, as the methods of choice for elucidating the molecular mechanisms of these compounds. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Parcels v0.9: prototyping a Lagrangian ocean analysis framework for the petascale age

NASA Astrophysics Data System (ADS)

Lange, Michael; van Sebille, Erik

2017-11-01

As ocean general circulation models (OGCMs) move into the petascale age, where the output of single simulations exceeds petabytes of storage space, tools to analyse the output of these models will need to scale up too. Lagrangian ocean analysis, where virtual particles are tracked through hydrodynamic fields, is an increasingly popular way to analyse OGCM output, by mapping pathways and connectivity of biotic and abiotic particulates. However, the current software stack of Lagrangian ocean analysis codes is not dynamic enough to cope with the increasing complexity, scale and need for customization of use-cases. Furthermore, most community codes are developed for stand-alone use, making it a nontrivial task to integrate virtual particles at runtime of the OGCM. Here, we introduce the new Parcels code, which was designed from the ground up to be sufficiently scalable to cope with petascale computing. We highlight its API design that combines flexibility and customization with the ability to optimize for HPC workflows, following the paradigm of domain-specific languages. Parcels is primarily written in Python, utilizing the wide range of tools available in the scientific Python ecosystem, while generating low-level C code and using just-in-time compilation for performance-critical computation. We show a worked-out example of its API, and validate the accuracy of the code against seven idealized test cases. This version 0.9 of Parcels is focused on laying out the API, with future work concentrating on support for curvilinear grids, optimization, efficiency and at-runtime coupling with OGCMs.

The dynamics of learning about a climate threshold

NASA Astrophysics Data System (ADS)

Keller, Klaus; McInerney, David

2008-02-01

Anthropogenic greenhouse gas emissions may trigger threshold responses of the climate system. One relevant example of such a potential threshold response is a shutdown of the North Atlantic meridional overturning circulation (MOC). Numerous studies have analyzed the problem of early MOC change detection (i.e., detection before the forcing has committed the system to a threshold response). Here we analyze the early MOC prediction problem. To this end, we virtually deploy an MOC observation system into a simple model that mimics potential future MOC responses and analyze the timing of confident detection and prediction. Our analysis suggests that a confident prediction of a potential threshold response can require century time scales, considerably longer that the time required for confident detection. The signal enabling early prediction of an approaching MOC threshold in our model study is associated with the rate at which the MOC intensity decreases for a given forcing. A faster MOC weakening implies a higher MOC sensitivity to forcing. An MOC sensitivity exceeding a critical level results in a threshold response. Determining whether an observed MOC trend in our model differs in a statistically significant way from an unforced scenario (the detection problem) imposes lower requirements on an observation system than the determination whether the MOC will shut down in the future (the prediction problem). As a result, the virtual observation systems designed in our model for early detection of MOC changes might well fail at the task of early and confident prediction. Transferring this conclusion to the real world requires a considerably refined MOC model, as well as a more complete consideration of relevant observational constraints.

Biologic effects of interferons.

PubMed

Gresser, I

1990-12-01

If one were to review articles on IFN published between 1957 and 1967 it would become apparent that virtually none of the tenets held then are still valid today. Whereas IFN was long considered to be a specific antiviral substance without any effect on normal cellular metabolism, we accept today that it affects normal cell division and many specialized cellular functions. In this respect it is not unique; IFN is a prototype of a family of similar substances now called cytokines that all appear to function as regulatory molecules. It was held that the production of IFN constituted a specific response to a viral infection. Today we believe that IFN is an integral part of a cytokine network and that they and other cytokines may be produced constitutively at low levels. These substances exert multiple effects on virtually all cells. They play an important role in host defense against viral and parasitic infections, and in the resistance to experimental tumors. IFN can be shown to exert effects on the immune system and on lymphocyte circulation. Lastly, because of the multiplicity of their biologic effects, they may even contribute to the pathogenesis of certain diseases. Thus, when large amounts of IFN are administered or induced in newborn mice they can cause liver, kidney, and pulmonary disease. The field of IFN and cytokine research continues to expand and there is an increasing number of therapeutic applications. Twenty years from now, scientists and clinicians may be surprised that we understood so little of how IFN act and how inadequately we used them to treat disease.

A numerical study of thermal stratification due to transient natural convection in densified liquid propellant tanks

NASA Astrophysics Data System (ADS)

Manalo, Lawrence B.

A comprehensive, non-equilibrium, two-domain (liquid and vapor), physics based, mathematical model is developed to investigate the onset and growth of the natural circulation and thermal stratification inside cryogenic propellant storage tanks due to heat transfer from the surroundings. A two-dimensional (planar) model is incorporated for the liquid domain while a lumped, thermodynamic model is utilized for the vapor domain. The mathematical model in the liquid domain consists of the conservation of mass, momentum, and energy equations and incorporates the Boussinesq approximation (constant fluid density except in the buoyancy term of the momentum equation). In addition, the vapor is assumed to behave like an ideal gas with uniform thermodynamic properties. Furthermore, the time-dependent nature of the heat leaks from the surroundings to the propellant (due to imperfect tank insulation) is considered. Also, heterogeneous nucleation, although not significant in the temperature range of study, has been included. The transport of mass and energy between the liquid and vapor domains leads to transient ullage vapor temperatures and pressures. (The latter of which affects the saturation temperature of the liquid at the liquid-vapor interface.) This coupling between the two domains is accomplished through an energy balance (based on a micro-layer concept) at the interface. The resulting governing, non-linear, partial differential equations (which include a Poisson's equation for determining the pressure distribution) in the liquid domain are solved by an implicit, finite-differencing technique utilizing a non-uniform (stretched) mesh (in both directions) for predicting the velocity and temperature fields. (The accuracy of the numerical scheme is validated by comparing the model's results to a benchmark numerical case as well as to available experimental data.) The mass, temperature, and pressure of the vapor is determined by using a simple explicit finite-differencing technique. With the model at hand, the effects of variable fluid transport/thermo-physical properties, levels of initial sub-cooling, operating pressure, and initial liquid aspect ratio on the natural circulation patterns and thermal stratification are numerically investigated. Liquid oxygen (LOx) is the primary working fluid in the study. However, a simulation with liquid nitrogen (LN2) as the propellant is also carried out for comparison purposes.

Analytical and numerical study on cooling flow field designs performance of PEM fuel cell with variable heat flux

NASA Astrophysics Data System (ADS)

Afshari, Ebrahim; Ziaei-Rad, Masoud; Jahantigh, Nabi

2016-06-01

In PEM fuel cells, during electrochemical generation of electricity more than half of the chemical energy of hydrogen is converted to heat. This heat of reactions, if not exhausted properly, would impair the performance and durability of the cell. In general, large scale PEM fuel cells are cooled by liquid water that circulates through coolant flow channels formed in bipolar plates or in dedicated cooling plates. In this paper, a numerical method has been presented to study cooling and temperature distribution of a polymer membrane fuel cell stack. The heat flux on the cooling plate is variable. A three-dimensional model of fluid flow and heat transfer in cooling plates with 15 cm × 15 cm square area is considered and the performances of four different coolant flow field designs, parallel field and serpentine fields are compared in terms of maximum surface temperature, temperature uniformity and pressure drop characteristics. By comparing the results in two cases, the constant and variable heat flux, it is observed that applying constant heat flux instead of variable heat flux which is actually occurring in the fuel cells is not an accurate assumption. The numerical results indicated that the straight flow field model has temperature uniformity index and almost the same temperature difference with the serpentine models, while its pressure drop is less than all of the serpentine models. Another important advantage of this model is the much easier design and building than the spiral models.