The evolution of misoscale circulations in a downburst-producing storm and comparison to numerical results

NASA Technical Reports Server (NTRS)

Kessinger, C. J.; Wilson, J. W.; Weisman, M.; Klemp, J.

1984-01-01

Data from three NCAR radars are used in both single and dual Doppler analyses to trace the evolution of a June 30, 1982 Colorado convective storm containing downburst-type winds and strong vortices 1-2 km in diameter. The analyses show that a series of small circulations formed along a persistent cyclonic shear boundary; at times as many as three misocyclones were present with vertical vorticity values as large as 0.1/s using a 0.25 km grid interval. The strength of the circulations suggests the possibility of accompanying tornadoes or funnels, although none were observed. Dual-Doppler analyses show that strong, small-scale downdrafts develop in close proximity to the misocyclones. A midlevel mesocyclone formed in the same general region of the storm where the misocylones later developed. The observations are compared with numerical simulations from a three-dimensional cloud model initialized with sounding data from the same day.

Evolution of hairpin vortices in a shear flow

NASA Technical Reports Server (NTRS)

Hon, T.-L.; Walker, J. D. A.

1988-01-01

Recent experimental studies suggest that the hairpin vortex plays an important (and perhaps dominant) role in the dynamics of turbulent flows near walls. In this study a numerical procedure is developed to allow the accurate computation of the trajectory of a 3-D vortex having a small core radius. For hairpin vortices which are convected in a shear flow above a wall, the calculated results show that a 2-D vortex containing a small 3-D disturbance distorts into a complex shape with subsidiary hairpin vortices forming outboard of the original hairpin vortex. As the vortex moves above the wall, it induces unsteady motion in the viscous flow near the wall: numerical solutions suggest that the boundary-layer flow near the wall will ultimately erupt in response to the motion of the hairpin vortex and in the process a secondary hairpin vortex will be created. The computer results agree with recent experimental investigations.

The nonlinear Galerkin method: A multi-scale method applied to the simulation of homogeneous turbulent flows

NASA Technical Reports Server (NTRS)

Debussche, A.; Dubois, T.; Temam, R.

1993-01-01

Using results of Direct Numerical Simulation (DNS) in the case of two-dimensional homogeneous isotropic flows, the behavior of the small and large scales of Kolmogorov like flows at moderate Reynolds numbers are first analyzed in detail. Several estimates on the time variations of the small eddies and the nonlinear interaction terms were derived; those terms play the role of the Reynolds stress tensor in the case of LES. Since the time step of a numerical scheme is determined as a function of the energy-containing eddies of the flow, the variations of the small scales and of the nonlinear interaction terms over one iteration can become negligible by comparison with the accuracy of the computation. Based on this remark, a multilevel scheme which treats differently the small and the large eddies was proposed. Using mathematical developments, estimates of all the parameters involved in the algorithm, which then becomes a completely self-adaptive procedure were derived. Finally, realistic simulations of (Kolmorov like) flows over several eddy-turnover times were performed. The results are analyzed in detail and a parametric study of the nonlinear Galerkin method is performed.

Matched Field Processing Based on Least Squares with a Small Aperture Hydrophone Array.

PubMed

Wang, Qi; Wang, Yingmin; Zhu, Guolei

2016-12-30

The receiver hydrophone array is the signal front-end and plays an important role in matched field processing, which usually covers the whole water column from the sea surface to the bottom. Such a large aperture array is very difficult to realize. To solve this problem, an approach called matched field processing based on least squares with a small aperture hydrophone array is proposed, which decomposes the received acoustic fields into depth function matrix and amplitudes of the normal modes at the beginning. Then all the mode amplitudes are estimated using the least squares in the sense of minimum norm, and the amplitudes estimated are used to recalculate the received acoustic fields of the small aperture array, which means the recalculated ones contain more environmental information. In the end, lots of numerical experiments with three small aperture arrays are processed in the classical shallow water, and the performance of matched field passive localization is evaluated. The results show that the proposed method can make the recalculated fields contain more acoustic information of the source, and the performance of matched field passive localization with small aperture array is improved, so the proposed algorithm is proved to be effective.

Matched Field Processing Based on Least Squares with a Small Aperture Hydrophone Array

PubMed Central

Wang, Qi; Wang, Yingmin; Zhu, Guolei

2016-01-01

The receiver hydrophone array is the signal front-end and plays an important role in matched field processing, which usually covers the whole water column from the sea surface to the bottom. Such a large aperture array is very difficult to realize. To solve this problem, an approach called matched field processing based on least squares with a small aperture hydrophone array is proposed, which decomposes the received acoustic fields into depth function matrix and amplitudes of the normal modes at the beginning. Then all the mode amplitudes are estimated using the least squares in the sense of minimum norm, and the amplitudes estimated are used to recalculate the received acoustic fields of the small aperture array, which means the recalculated ones contain more environmental information. In the end, lots of numerical experiments with three small aperture arrays are processed in the classical shallow water, and the performance of matched field passive localization is evaluated. The results show that the proposed method can make the recalculated fields contain more acoustic information of the source, and the performance of matched field passive localization with small aperture array is improved, so the proposed algorithm is proved to be effective. PMID:28042828

High sequence variations in the region containing genes encoding a cellular morphogenesis protein and the repressor of sexual development help to reveal origins of Aspergillus oryzae

USDA-ARS?s Scientific Manuscript database

Aspergillus oryzae and Aspergillus flavus are closely related fungal species. The A. flavus population that produces numerous small sclerotia (S strain) and aflatoxin has a unique 1.5 kb deletion in the norB-cypA region of the aflatoxin gene cluster (the S genotype). Phylogenetic studies have indica...

New numerical solutions of three-dimensional compressible hydrodynamic convection. [in stars

NASA Technical Reports Server (NTRS)

Hossain, Murshed; Mullan, D. J.

1990-01-01

Numerical solutions of three-dimensional compressible hydrodynamics (including sound waves) in a stratified medium with open boundaries are presented. Convergent/divergent points play a controlling role in the flows, which are dominated by a single frequency related to the mean sound crossing time. Superposed on these rapid compressive flows, slower eddy-like flows eventually create convective transport. The solutions contain small structures stacked on top of larger ones, with vertical scales equal to the local pressure scale heights, H sub p. Although convective transport starts later in the evolution, vertical scales of H sub p are apparently selected at much earlier times by nonlinear compressive effects.

Reaction Rate of Small Diffusing Molecules on a Cylindrical Membrane

NASA Astrophysics Data System (ADS)

Straube, Ronny; Ward, Michael J.; Falcke, Martin

2007-10-01

Biomembranes consist of a lipid bi-layer into which proteins are embedded to fulfill numerous tasks in localized regions of the membrane. Often, the proteins have to reach these regions by simple diffusion. Motivated by the observation that IP3 receptor channels (IP3R) form clusters on the surface of the endoplasmic reticulum (ER) during ATP-induced calcium release, the reaction rate of small diffusing molecules on a cylindrical membrane is calculated based on the Smoluchowski approach. In this way, the cylindrical topology of the tubular ER is explicitly taken into account. The problem can be reduced to the solution of the diffusion equation on a finite cylindrical surface containing a small absorbing hole. The solution is constructed by matching appropriate `inner' and `outer' asymptotic expansions. The asymptotic results are compared with those from numerical simulations and excellent agreement is obtained. For realistic parameter sets, we find reaction rates in the range of experimentally measured clustering rates of IP3R. This supports the idea that clusters are formed by a purely diffusion limited process.

Polarized Ends of Human Macula Densa Cells: Ultrastructural Investigation and Morphofunctional Correlations.

PubMed

Cangiotti, Angela Maria; Lorenzi, Teresa; Zingaretti, Maria Cristina; Fabri, Mara; Morroni, Manrico

2018-05-01

The morphology of the kidney macula densa (MD) has extensively been investigated in animals, whereas human studies are scanty. We studied the fine structure of human MD cells focusing on their apical and basal ends and correlating structure and function. The MD region was examined by transmission electron microscopy in six renal biopsies from patients with kidney disease. Ultrastructural analysis of MD cells was performed on serial sections. MD cells show two polarized ends. The apical portion is characterized by a single, immotile cilium associated with microvilli; apically, cells are joined by adhering junctions. In the basal portion, the cytoplasm contains small, dense granules and numerous, irregular cytoplasmic projections extending to the adjacent extraglomerular mesangium. The projections often contain small, dense granules. A reticulated basement membrane around MD cells separates them from the extraglomerular mesangium. Although the fact that tissue specimens came from patients with kidney disease mandates extreme caution, ultrastructural examination confirmed that MD cells have sensory features due to the presence of the primary cilium, that they are connected by apical adhering junctions forming a barrier that separates the tubular flow from the interstitium, and that they present numerous basal interdigitations surrounded by a reticulated basement membrane. Conceivably, the latter two features are related to the functional activity of the MD. The small, dense granules in the basal cytoplasm and in cytoplasmic projections are likely related to the paracrine function of MD cells. Anat Rec, 301:922-931, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

An RNA motif that binds ATP

NASA Technical Reports Server (NTRS)

Sassanfar, M.; Szostak, J. W.

1993-01-01

RNAs that contain specific high-affinity binding sites for small molecule ligands immobilized on a solid support are present at a frequency of roughly one in 10(10)-10(11) in pools of random sequence RNA molecules. Here we describe a new in vitro selection procedure designed to ensure the isolation of RNAs that bind the ligand of interest in solution as well as on a solid support. We have used this method to isolate a remarkably small RNA motif that binds ATP, a substrate in numerous biological reactions and the universal biological high-energy intermediate. The selected ATP-binding RNAs contain a consensus sequence, embedded in a common secondary structure. The binding properties of ATP analogues and modified RNAs show that the binding interaction is characterized by a large number of close contacts between the ATP and RNA, and by a change in the conformation of the RNA.

Rapidly expanding genetic diversity and host range of the Circoviridae viral family and other Rep encoding small circular ssDNA genomes

PubMed Central

Delwart, Eric; Li, Linlin

2011-01-01

The genomes of numerous circoviruses and distantly related circular DNA viruses encoding a rolling circle replication initiator protein (Rep) have been characterized from the tissues of mammals, fish, insects, and plants (geminivirus and nanovirus), human and animal feces, in an algae cell, and in diverse environmental samples. We review the genome organization, phylogenetic relationships and initial prevalence studies of cycloviruses, a proposed new genus in the Circoviridae family. Viral fossil rep sequences were also identified integrated on the chromosomes of mammals, frogs, lancelets, crustaceans, mites, gastropods, roundworms, placozoans, hydrozoans, protozoans, land plants, fungi, algae, and phytoplasma bacterias and their plasmids, reflecting their past host range. An ancient origin for viruses with rep-encoding single stranded small circular genomes, predating the diversification of eukaryotes, is discussed. The cellular hosts and pathogenicity of many recently described rep-containing circular genomes remain to be determined. Future studies of the virome of single cell and multi-cellular eukaryotes are likely to further extend the known diversity and host-range of small rep-containing circular viral genomes. PMID:22155583

On the structure of cellular solutions in Rayleigh-Benard-Marangoni flows in small-aspect-ratio containers

NASA Technical Reports Server (NTRS)

Dijkstra, Henk A.

1992-01-01

Multiple steady flow patterns occur in surface-tension/buoyancy-driven convection in a liquid layer heated from below (Rayleigh-Benard-Marangoni flows). Techniques of numerical bifurcation theory are used to study the multiplicity and stability of two-dimensional steady flow patterns (rolls) in rectangular small-aspect-ratio containers as the aspect ratio is varied. For pure Marangoni flows at moderate Biot and Prandtl number, the transitions occurring when paths of codimension 1 singularities intersect determine to a large extent the multiplicity of stable patterns. These transitions also lead, for example, to Hopf bifurcations and stable periodic flows for a small range in aspect ratio. The influence of the type of lateral walls on the multiplicity of steady states is considered. 'No-slip' lateral walls lead to hysteresis effects and typically restrict the number of stable flow patterns (with respect to 'slippery' sidewalls) through the occurrence of saddle node bifurcations. In this way 'no-slip' sidewalls induce a selection of certain patterns, which typically have the largest Nusselt number, through secondary bifurcation.

Ultrastructure studies on the papillae and the nonciliated sensory receptors of adult Spirometra erinacei (Cestoda, Pseudophyllidea).

PubMed

Okino, T; Hatsushika, R

1994-01-01

The small numerous papillae on the ventral surface of the gravid proglottid of adult Spirometra erinacei were studied by scanning electron microscopy. The arrangement of clumps of papillae was recognized on the surface of the central portion around the genital atrium, with lateral clumps being located above a pair of longitudinal nerve cords and marginal ones, on both sides of the proglottid. By transmission electron microscopy, two types of nonciliated sensory receptors were observed within the papillae. The type I, single receptor was embedded within a papilla. This dome-like sensory receptor contained two electron-dense collars and four rootlets surrounded by numerous thin filaments. The type II receptor was found arranged in groups in the area between the papillae, and the apical end was exposed to the external environment. This simple, club-like sensory receptor contained electron-lucent vesicles and microtubules. We believe that the papillae play an important role in cross-insemination.

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

NASA Technical Reports Server (NTRS)

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

2006-01-01

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

Virtual containment system for composite flywheels

NASA Astrophysics Data System (ADS)

Shiue, Fuh-Wen

2001-07-01

There is much interest in advanced composite flywheel systems for use on satellites mainly because of the potential for considerable weight savings associated with combined energy and momentum management. The additional weight of a containment system needed to protect the satellite in the event of a flywheel failure, however, could negate the potential savings. Therefore, the development of a condition monitoring and virtual containment system is essential to ensure the wide acceptance of flywheel batteries for spacecraft applications. A virtual containment system is a near real-time condition monitoring system, plus additional logic to adjust the operating conditions (maximum rotational speed) accordingly when a flaw or fault is detected. Flaws of primary interest in this study are those unique to composite flywheels, such as delamination and debonding of interfaces. Such flaws change the balance state of a flywheel through small, but detectable, motion of the mass center and principal axes of inertia. A proposed monitoring technique determines the existence and the extent of such flaws by a method similar to the influence-coefficient rotor balancing method. Because of the speed-dependence of the imbalance caused by elastic flaws, a normalized imbalance change, which is a direct measure of the flaw size, was defined. To account for the possibility that flaw growth could actually improve the balance state of a rotor, a new concept of accumulated imbalance change was also introduced. Laboratory tests showed the proposed method was able to detect small simulated flaws that result in as little as 2--3 microns of mass center movement. Fracture mechanics concepts were used to evaluate the severity and growth rate of the detected flaw. An interesting discovery that coincided with some experimental observations reported in the literature was the energy release rate reduction with a large crack. This finding indicates a possible stress relief and crack arrest when a circumferential crack grows over certain size. This phenomenon is largely due to crack curvature unique to filament-wound composite flywheels. Several virtual containment strategies were investigated numerically to demonstrate the feasibility of virtual containment systems. Once a flaw is detected during flywheel operation, the maximum operating speed can be reduced to prevent catastrophic failure, achieve a specific design life, and maximize energy storage capacity over the remaining life. A numerical example showed 4--5 times of improvement in cumulative energy storage through lifetime with a virtual containment. A closed-loop speed controller using condition monitoring sensor feedback was investigated numerically to account for possible imperfection of the fracture mechanics model. Finally, an integrated virtual containment system without any complex fracture mechanics analysis was also developed and successfully demonstrated experimentally.

Non-robust numerical simulations of analogue extension experiments

NASA Astrophysics Data System (ADS)

Naliboff, John; Buiter, Susanne

2016-04-01

Numerical and analogue models of lithospheric deformation provide significant insight into the tectonic processes that lead to specific structural and geophysical observations. As these two types of models contain distinct assumptions and tradeoffs, investigations drawing conclusions from both can reveal robust links between first-order processes and observations. Recent studies have focused on detailed comparisons between numerical and analogue experiments in both compressional and extensional tectonics, sometimes involving multiple lithospheric deformation codes and analogue setups. While such comparisons often show good agreement on first-order deformation styles, results frequently diverge on second-order structures, such as shear zone dip angles or spacing, and in certain cases even on first-order structures. Here, we present finite-element experiments that are designed to directly reproduce analogue "sandbox" extension experiments at the cm-scale. We use material properties and boundary conditions that are directly taken from analogue experiments and use a Drucker-Prager failure model to simulate shear zone formation in sand. We find that our numerical experiments are highly sensitive to numerous numerical parameters. For example, changes to the numerical resolution, velocity convergence parameters and elemental viscosity averaging commonly produce significant changes in first- and second-order structures accommodating deformation. The sensitivity of the numerical simulations to small parameter changes likely reflects a number of factors, including, but not limited to, high angles of internal friction assigned to sand, complex, unknown interactions between the brittle sand (used as an upper crust equivalent) and viscous silicone (lower crust), highly non-linear strain weakening processes and poor constraints on the cohesion of sand. Our numerical-analogue comparison is hampered by (a) an incomplete knowledge of the fine details of sand failure and sand properties, and (b) likely limitations to the use of a continuum Drucker-Prager model for representing shear zone formation in sand. In some cases our numerical experiments provide reasonable fits to first-order structures observed in the analogue experiments, but the numerical sensitivity to small parameter variations leads us to conclude that the numerical experiments are not robust.

AN ELECTRON MICROSCOPE STUDY OF MATURE AND DIFFERENTIATING PANETH CELLS IN THE RAT, ESPECIALLY OF THEIR ENDOPLASMIC RETICULUM AND LYSOSOMES

PubMed Central

Behnke, O.; Moe, H.

1964-01-01

In an electron microsope study, the morphology of mature Paneth cells from the small intestine of adult rats is compared with that of differentiating Paneth cells from young rats 2 to 4 weeks old. All mature cells exhibit a marked polarity similar to that of other exocrine gland cells and contain a well developed endoplasmic reticulum, an elaborate Golgi complex, and numerous large secretory granules; they also possess an abundance of lysosomes. The most conspicuous occurrence in the process of differentiation is the development of the endoplasmic reticulum. The most immature Paneth cells possess an endoplasmic reticulum of the vesicular type, which, during maturation, is replaced by the characteristic lamellated ergastoplasm of the mature cell. At a certain stage of differentiation the cavities of the developing cisternae show numerous communications with the perinuclear space, suggesting an outgrowth of the ergastoplasm from the nuclear envelope. Furthermore, the cavities and the perinuclear space at this particular stage contain a material which shows a remarkable intrinsic periodicity. An identical periodicity was exhibited by material contained in Golgi cisternae and secretory granules. Lysosomes are also present in the differentiating cells. PMID:14206428

ROLE OF SMALL OIL AND GAS FIELDS IN THE UNITED STATES.

USGS Publications Warehouse

Meyer, Richard F.; Fleming, Mary L.

1985-01-01

The actual economic size cutoff is a function of such factors as depth, water depth offshore, and accessibility to transportation infrastructure. Because of the constraint of resource availability, price is now the principal force driving drilling activity. The proportion of new-field wildcats to other exploratory wells has fallen in recent years, but success in new-field wildcats has risen to about 20%. However, only very small fields, less than 1 million BOE, are being found in large numbers. Through 1979, almost 93% of known gas fields and 94. 5% of known oil fields were small, yet they contain only 14. 5% of the ultimately recoverable gas and 12. 5% of the oil. However, small fields are less capital intensive than equivalent-capacity synthetic-fuel plants, they are extremely numerous, and they are relatively easy and inexpensive to find and put on production. Refs.

South Greenland, North Atlantic Ocean

NASA Technical Reports Server (NTRS)

1992-01-01

This spectacular north looking view of south Greenland (62.0N, 46.0W) shows numerous indentations along the coastline, many of which contain small settlements. These indentations are fiords carved by glaciers of the last ice age. Even today, ice in the center of Greenland is as much as 10,000 ft. thick and great rivers of ice continuously flow toward the sea, where they melt or break off as icebergs - some of which may be seen floating offshore.

South Greenland, North Atlantic Ocean

NASA Image and Video Library

1992-04-02

This spectacular north looking view of south Greenland (62.0N, 46.0W) shows numerous indentations along the coastline, many of which contain small settlements. These indentations are fiords carved by glaciers of the last ice age. Even today, ice in the center of Greenland is as much as 10,000 ft. thick and great rivers of ice continuously flow toward the sea, where they melt or break off as icebergs - some of which may be seen floating offshore.

Numerical and Permeability Constraints on Simulation of Sill-Driven Hydrothermal Convection

NASA Astrophysics Data System (ADS)

Carr, P. M.; Cathles, L. M.; Barrie, C. T.; Manhardt, P.

2004-05-01

Volcanic-associated massive sulfide deposits are formed where seawater, heated to ~350oC by subsurface magma intrusions, is quenched by cold water at or near the seafloor. Many VMS districts, like the one at Matagami, Quebec, contain their zinc, lead, and copper in about a dozen discrete ore bodies, with one or two deposits containing more than half of the district's resources. We construct numerical models to investigate the causes of variations in deposit size. These models show that a process which stabilizes the location of hydrothermal venting plumes is required to numerically generate discrete VMS ore bodies by sill-driven hydrothermal convection. This is achieved in our models by increasing rock permeability in a fashion that makes vent plumes more permeable than their surroundings. Maintaining the Courant number ≤1 (so that a thermal anomaly traverses only one grid cell in one timestep of the simulation) is shown to be crucial to numerical convergence. If this rule is violated, visually compelling but incorrect hydrothermal vents result. Small hydrothermal convection cells over the interior of an areally-extensive sill with a tabular edge are smaller than those formed at the sill edge. However, for a sill with the geometry of that at Matagami, numerical simulations indicate that large ore deposits should form near the thickest part of the sill where metals extracted from the underside of the still-hot portions of the sill can optimally contribute. Thus it is essential to construct a model of the entire domain rather than slicing a portion local to the deposition. The numerical models replicate the ten-fold range in deposit size variation, and predict the largest deposits at Matagami will be discovered at 5 to 8 km depth between currently known deposits in the South Flank and Phelps Dodge areas.

The Quantity and Quality of Scientific Graphs in Pharmaceutical Advertisements

PubMed Central

Cooper, Richelle J; Schriger, David L; Wallace, Roger C; Mikulich, Vladislav J; Wilkes, Michael S

2003-01-01

We characterized the quantity and quality of graphs in all pharmaceutical advertisements, in the 10 U.S. medical journals. Four hundred eighty-four unique advertisements (of 3,185 total advertisements) contained 836 glossy and 455 small-print pages. Forty-nine percent of glossy page area was nonscientific figures/images, 0.4% tables, and 1.6% scientific graphs (74 graphs in 64 advertisements). All 74 graphs were univariate displays, 4% were distributions, and 4% contained confidence intervals for summary measures. Extraneous decoration (66%) and redundancy (46%) were common. Fifty-eight percent of graphs presented an outcome relevant to the drug's indication. Numeric distortion, specifically prohibited by FDA regulations, occurred in 36% of graphs. PMID:12709097

Acremonium phylogenetic overview and revision of Gliomastix, Sarocladium, and Trichothecium.

PubMed

Summerbell, R C; Gueidan, C; Schroers, H-J; de Hoog, G S; Starink, M; Rosete, Y Arocha; Guarro, J; Scott, J A

2011-01-01

Over 200 new sequences are generated for members of the genus Acremonium and related taxa including ribosomal small subunit sequences (SSU) for phylogenetic analysis and large subunit (LSU) sequences for phylogeny and DNA-based identification. Phylogenetic analysis reveals that within the Hypocreales, there are two major clusters containing multiple Acremonium species. One clade contains Acremonium sclerotigenum, the genus Emericellopsis, and the genus Geosmithia as prominent elements. The second clade contains the genera Gliomastixsensu stricto and Bionectria. In addition, there are numerous smaller clades plus two multi-species clades, one containing Acremonium strictum and the type species of the genus Sarocladium, and, as seen in the combined SSU/LSU analysis, one associated subclade containing Acremonium breve and related species plus Acremonium curvulum and related species. This sequence information allows the revision of three genera. Gliomastix is revived for five species, G. murorum, G. polychroma, G. tumulicola, G. roseogrisea, and G. masseei. Sarocladium is extended to include all members of the phylogenetically distinct A. strictum clade including the medically important A. kiliense and the protective maize endophyte A. zeae. Also included in Sarocladium are members of the phylogenetically delimited Acremonium bacillisporum clade, closely linked to the A. strictum clade. The genus Trichothecium is revised following the principles of unitary nomenclature based on the oldest valid anamorph or teleomorph name, and new combinations are made in Trichothecium for the tightly interrelated Acremonium crotocinigenum, Spicellum roseum, and teleomorph Leucosphaerinaindica. Outside the Hypocreales, numerous Acremonium-like species fall into the Plectosphaerellaceae, and A. atrogriseum falls into the Cephalothecaceae.

The Aeronautics Education, Research, and Industry Alliance (AERIAL) 2002 Report

NASA Technical Reports Server (NTRS)

Bowen, Brent D.; Fink, Mary M.; Nickerson, Jocelyn S.

2002-01-01

This report presents and overview of the Aeronautics Education, Research, and Industry Alliance (AERIAL). It covers the University of Nebraska's areas of research, and its outreach to students at Native American schools as part of AERIAL. The report contains three papers: "Airborne Remote Sensing (ARS) for Agricultural Research and Commercialization Application" (White Paper), "Validated Numerical Models for the Convective Extinction of Fuel Droplets (CEFD)", and "The Small Aircraft Transportation System (SATS): Research Collaborations with the NASA Langley Research Center".

Disseminated toxoplasmosis in black-footed penguins (Spheniscus demersus).

PubMed

Ploeg, Margreet; Ultee, Ton; Kik, Marja

2011-12-01

Three 1- to 3-mo-old black-footed penguins (Spheniscus Demersus) died within 24 hr of showing central nervous signs such as ataxia. The birds were housed in a baby penguin crèche. At necropsy, peritonitis, pneumonia, hepatomegaly, splenomegaly, and renomegaly were evident. Histologically, the liver, lung, brain, and small intestine contained numerous tachyzoites and a few cysts of Toxoplasma. Immunohistochemistry identified the protozoal parasites as Toxoplasma gondii. Ultrastructurally, this was confirmed by the presence of many tachyzoites of T. gondii in the liver and lungs.

Lateral trapping of DNA inside a voltage gated nanopore

NASA Astrophysics Data System (ADS)

Töws, Thomas; Reimann, Peter

2017-06-01

The translocation of a short DNA fragment through a nanopore is addressed when the perforated membrane contains an embedded electrode. Accurate numerical solutions of the coupled Poisson, Nernst-Planck, and Stokes equations for a realistic, fully three-dimensional setup as well as analytical approximations for a simplified model are worked out. By applying a suitable voltage to the membrane electrode, the DNA can be forced to preferably traverse the pore either along the pore axis or at a small but finite distance from the pore wall.

The National Shipbuilding Research Program. 1997 Ship Production Symposium. Implementation of Integrated CAD/CAM Systems in Small and Medium Sized Shipyards: A Case Study

DTIC Science & Technology

1997-04-01

implied, with respect to the accuracy, completeness or usefulness of the information contained in this report/ manual , or that the use of any information...shipyards throughout the world have introduced various aspects of CAD/CAM piecemeal as substitutes for manual processes, the greatest improvement in...possibility of multiple models of the molded geometry being developed, which would cause the loss of geometry control. Numerous AutoLisp routines were used

Comprehensive proteomic analysis of the human spliceosome

NASA Astrophysics Data System (ADS)

Zhou, Zhaolan; Licklider, Lawrence J.; Gygi, Steven P.; Reed, Robin

2002-09-01

The precise excision of introns from pre-messenger RNA is performed by the spliceosome, a macromolecular machine containing five small nuclear RNAs and numerous proteins. Much has been learned about the protein components of the spliceosome from analysis of individual purified small nuclear ribonucleoproteins and salt-stable spliceosome `core' particles. However, the complete set of proteins that constitutes intact functional spliceosomes has yet to be identified. Here we use maltose-binding protein affinity chromatography to isolate spliceosomes in highly purified and functional form. Using nanoscale microcapillary liquid chromatography tandem mass spectrometry, we identify ~145 distinct spliceosomal proteins, making the spliceosome the most complex cellular machine so far characterized. Our spliceosomes comprise all previously known splicing factors and 58 newly identified components. The spliceosome contains at least 30 proteins with known or putative roles in gene expression steps other than splicing. This complexity may be required not only for splicing multi-intronic metazoan pre-messenger RNAs, but also for mediating the extensive coupling between splicing and other steps in gene expression.

The cardiac ultrastructure of Chimaera monstrosa L. (Elasmobranchii: Holocephali).

PubMed

Berge, P I

1979-09-03

The ultrastructure of the heart in Chimaera monstrosa L. is described. The endocardial and the epicardial cells are similar in the three cardiac regions. Myocardial cells show small variations. The myofibred, 4--6 microns thick, contains one or a few myofibrils. Each myosin filament is surrounded by six actin filaments. The sarcomere banding pattern includes the Z-, A-, I-, M-, N-, and H-band. End-to-end attachments between myofibres are composed of alternating desmosomes and fasciae adhaerentes. Desmosomes and nexuses occur between longitudinally oriented cell surfaces. The sarcoplasmic reticulum is poorly developed but well defined. Peripheral coupling-like structures are common, T-tubules are absent. Membrane bound dense bodies occur in all regions. Areas with ribosomes and single myosin filaments are often seen. The epicardial cells have a regular hexagonal surface and are much thicker than the endocardial cells. Numerous short and few longer cytoplasmic extensions face the pericardial cavity. The flat endocardial cells contain a large nucleus and small amounts of cytoplasm.

Surface topography and ultrastructural changes of mucinous carcinoma breast cells.

PubMed

Voloudakis, G E; Baltatzis, G E; Agnantis, N J; Arnogianaki, N; Misitzis, J; Voloudakis-Baltatzis, I

2007-01-01

Mucinous carcinoma of the breast (MCB) is histologically classified into 2 groups: (1) pure MCB and (2) mixed MCB. Pure MCB carries a better diagnosis than mixed MCB. This research relates to the cell surface topography and ultrastructure of the cells in the above cases and aims to find the differences between them, by means of two methods: scanning electron microscopy (SEM) and transmission electron microscopy (TEM). For the SEM examination, it was necessary to initially culture the MCB tissues and then proceed with the usual SEM method. In contrast, for the TEM technique, MCB tissues were initially fixed followed by the classic TEM method. The authors found the topography of pure MCB cases to be without nodes. The cell membrane was smooth, with numerous pores and small ruffles that covered the entire cell. The ultrastructural appearance of the same cases was with a normal cell membrane containing abundant collagen fibers. They also had many small vesicles containing mucin as well as secretory droplets. In contrast the mixed MCB had a number of lymph nodes and their cell surface topography showed stronger changes such as microvilli, numerous blebs, ruffles and many long projections. Their ultrastructure showed very long microvilli with large cytoplasmic inclusions and extracellular mucin collections, electron-dense material vacuoles, and many important cytoplasmic organelles. An important fact is that mixed MCB also contains areas of infiltrating ductal carcinoma. These cells of the cytoplasmic organelles are clearly responsible for the synthesis, storage, and secretion of the characteristic mucin of this tumor type. Evidently, this abnormal mucin production and the abundance of secretory granules along with the long projections observed in the topographical structure might be responsible for transferring tumor cells to neighboring organs, thus being responsible for metastatic disease.

THE FINE STRUCTURE OF MEISSNER's TOUCH CORPUSCLES OF HUMAN FINGERS

PubMed Central

Cauna, Nikolajs; Ross, Leonard L.

1960-01-01

Thin slices of the finger pads of six individuals were fixed in buffered 1 per cent osmic acid, embedded in deaerated, nitrogenated methacrylate, and cut into thin sections for electron microscopic study. Before embedding, the slices were trimmed so as to include several digital tactile corpuscles. Some thin sections were stained in 10 per cent aqueous phosphotungstic acid solution. The principal part of Meissner's corpuscle is made up of flattened laminar cells stretching across the corpuscle in irregular layers. The perinuclear cytoplasm of these cells contains numerous small mitochondria, a sparse granular endoplasmic reticulum, and a large number of small vesicles. Nerve fibers enter the side or base of the corpuscle, lose their myelin sheaths, and follow a meandering course between the laminar cell plates. The nerve endings enter into a close appositional relationship with the flattened portions of the laminar cells. In some areas the apposed axolemma and cell membranes are slightly thickened with small vesicles located along the cell membrane or on both surfaces. These regions are interpreted as synapses. The most prominent feature of the nerve endings is an extraordinary accumulation of small mitochondria which vary in size and internal density. The nerve endings also contain vacuoles, groups of dense concentric membranes, and small dense vesicles of irregular distribution. The laminar cells are separated from one another by a dense intercellular substance of uniform thickness which also envelops the entire corpuscle. This material contains randomly oriented collagen fibers and fine fibrils bound together by a dense material at nodal points recurring at regular intervals of approximately 120 mµ. These findings are discussed in relation to the problems of the function of Meissner's corpuscle, neural material loss and replacement, and the presence of synapses. PMID:13691669

Rapidly expanding genetic diversity and host range of the Circoviridae viral family and other Rep encoding small circular ssDNA genomes.

PubMed

Delwart, Eric; Li, Linlin

2012-03-01

The genomes of numerous circoviruses and distantly related circular ssDNA viruses encoding a rolling circle replication initiator protein (Rep) have been characterized from the tissues of mammals, fish, insects, plants (geminivirus and nanovirus), in human and animal feces, in an algae cell, and in diverse environmental samples. We review the genome organization, phylogenetic relationships and initial prevalence studies of cycloviruses, a proposed new genus in the Circoviridae family. Viral fossil rep sequences were also recently identified integrated on the chromosomes of mammals, frogs, lancelets, crustaceans, mites, gastropods, roundworms, placozoans, hydrozoans, protozoans, land plants, fungi, algae, and phytoplasma bacterias and their plasmids, reflecting the very wide past host range of rep bearing viruses. An ancient origin for viruses with Rep-encoding small circular ssDNA genomes, predating the diversification of eukaryotes, is discussed. The cellular hosts and pathogenicity of many recently described rep-containing circular ssDNA genomes remain to be determined. Future studies of the virome of single cell and multi-cellular eukaryotes are likely to further extend the known diversity and host-range of small rep-containing circular ssDNA viral genomes. Copyright © 2011 Elsevier B.V. All rights reserved.

Numerical solutions of the semiclassical Boltzmann ellipsoidal-statistical kinetic model equation

PubMed Central

Yang, Jaw-Yen; Yan, Chin-Yuan; Huang, Juan-Chen; Li, Zhihui

2014-01-01

Computations of rarefied gas dynamical flows governed by the semiclassical Boltzmann ellipsoidal-statistical (ES) kinetic model equation using an accurate numerical method are presented. The semiclassical ES model was derived through the maximum entropy principle and conserves not only the mass, momentum and energy, but also contains additional higher order moments that differ from the standard quantum distributions. A different decoding procedure to obtain the necessary parameters for determining the ES distribution is also devised. The numerical method in phase space combines the discrete-ordinate method in momentum space and the high-resolution shock capturing method in physical space. Numerical solutions of two-dimensional Riemann problems for two configurations covering various degrees of rarefaction are presented and various contours of the quantities unique to this new model are illustrated. When the relaxation time becomes very small, the main flow features a display similar to that of ideal quantum gas dynamics, and the present solutions are found to be consistent with existing calculations for classical gas. The effect of a parameter that permits an adjustable Prandtl number in the flow is also studied. PMID:25104904

Casimir interaction of rodlike particles in a two-dimensional critical system.

PubMed

Eisenriegler, E; Burkhardt, T W

2016-09-01

We consider the fluctuation-induced interaction of two thin, rodlike particles, or "needles," immersed in a two-dimensional critical fluid of Ising symmetry right at the critical point. Conformally mapping the plane containing the needles onto a simpler geometry in which the stress tensor is known, we analyze the force and torque between needles of arbitrary length, separation, and orientation. For infinite and semi-infinite needles we utilize the mapping of the plane bounded by the needles onto the half plane, and for two needles of finite length we use the mapping onto an annulus. For semi-infinite and infinite needles the force is expressed in terms of elementary functions, and we also obtain analytical results for the force and torque between needles of finite length with separation much greater than their length. Evaluating formulas in our approach numerically for several needle geometries and surface universality classes, we study the full crossover from small to large values of the separation to length ratio. In these two limits the numerical results agree with results for infinitely long needles and with predictions of the small-particle operator expansion, respectively.

A Simple Compression Scheme Based on ASCII Value Differencing

NASA Astrophysics Data System (ADS)

Tommy; Siregar, Rosyidah; Lubis, Imran; Marwan E, Andi; Mahmud H, Amir; Harahap, Mawaddah

2018-04-01

ASCII characters have a different code representation where each character has a different numeric value between the characters to each other. The characters is usually used as a text message communication has the representation of a numeric code to each other or have a small difference. The value of the difference can be used as a substitution of the characters so it will generate a new message with a size that is a little more. This paper discusses the utilization value of the difference of characters ASCII in a message to a much simpler substitution by using a dynamic-sized window in order to obtain the difference from ASCII value contained on the window as the basis in determining the bit substitution on the file compression results.

Characterization of LANDSAT-4 TM and MSS Image Quality for Interpretation of Agricultural and Forest Resources

NASA Technical Reports Server (NTRS)

Degloria, S. D.; Colwell, R. N.

1984-01-01

Systematic analysis of both image and numeric data shows that the overall spectral, spatial, and radiometric quality of the TM data are excellent. Spectral variations in fallow fields are due to the vaiability in soil moisture and surface roughness resulting from the various stages of field preparation for small grains production. Spectrally, the addition of the first TM short wave infrared band (Band 5) significantly enhanced ability to discriminate different crop types. Bands 1, 5, and 6 contain saturated pixels due to high albedo effects, low moisture conditions, and high radiant temperatures of granite and dry, bare soil on south facing slopes, respectively. Spatially, the two fold decrease in interpixel distance and four fold decrease in area per pixel between the TM and MSS allow for improved discrimination of small fields, boundary conditions, road and stream networks in rough terrain, and small forest clearings resulting from various forest management practices.

A new class of finite element variational multiscale turbulence models for incompressible magnetohydrodynamics

DOE PAGES

Sondak, D.; Shadid, J. N.; Oberai, A. A.; ...

2015-04-29

New large eddy simulation (LES) turbulence models for incompressible magnetohydrodynamics (MHD) derived from the variational multiscale (VMS) formulation for finite element simulations are introduced. The new models include the variational multiscale formulation, a residual-based eddy viscosity model, and a mixed model that combines both of these component models. Each model contains terms that are proportional to the residual of the incompressible MHD equations and is therefore numerically consistent. Moreover, each model is also dynamic, in that its effect vanishes when this residual is small. The new models are tested on the decaying MHD Taylor Green vortex at low and highmore » Reynolds numbers. The evaluation of the models is based on comparisons with available data from direct numerical simulations (DNS) of the time evolution of energies as well as energy spectra at various discrete times. Thus a numerical study, on a sequence of meshes, is presented that demonstrates that the large eddy simulation approaches the DNS solution for these quantities with spatial mesh refinement.« less

Numerical study of a stochastic particle algorithm solving a multidimensional population balance model for high shear granulation

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

Braumann, Andreas; Kraft, Markus, E-mail: mk306@cam.ac.u; Wagner, Wolfgang

2010-10-01

This paper is concerned with computational aspects of a multidimensional population balance model of a wet granulation process. Wet granulation is a manufacturing method to form composite particles, granules, from small particles and binders. A detailed numerical study of a stochastic particle algorithm for the solution of a five-dimensional population balance model for wet granulation is presented. Each particle consists of two types of solids (containing pores) and of external and internal liquid (located in the pores). Several transformations of particles are considered, including coalescence, compaction and breakage. A convergence study is performed with respect to the parameter that determinesmore » the number of numerical particles. Averaged properties of the system are computed. In addition, the ensemble is subdivided into practically relevant size classes and analysed with respect to the amount of mass and the particle porosity in each class. These results illustrate the importance of the multidimensional approach. Finally, the kinetic equation corresponding to the stochastic model is discussed.« less

New lumped-mass-stick model based on modal characteristics of structures: development and application to a nuclear containment building

NASA Astrophysics Data System (ADS)

Roh, Hwasung; Lee, Huseok; Lee, Jong Seh

2013-06-01

In this study, a new lumped-mass-stick model (LMSM) is developed based on the modal characteristics of a structure such as eigenvalues and eigenvectors. The simplified model, named the "frequency adaptive lumped-massstick model," hasonly a small number of stick elements and nodes to provide the same natural frequencies of the structure and is applied to a nuclear containment building. To investigate the numerical performance of the LMSM, a time history analysis is carried out on both the LMSM and the finite element model (FEM) for a nuclear containment building. A comparison of the results shows that the dynamic responses of the LMSM in terms of displacement and acceleration are almost identical to those of the FEM. In addition, the results in terms of fl oor response spectra at certain elevations are also in good agreement.

Acremonium phylogenetic overview and revision of Gliomastix, Sarocladium, and Trichothecium

PubMed Central

Summerbell, R.C.; Gueidan, C.; Schroers, H-J.; de Hoog, G.S.; Starink, M.; Rosete, Y. Arocha; Guarro, J.; Scott, J.A.

2011-01-01

Over 200 new sequences are generated for members of the genus Acremonium and related taxa including ribosomal small subunit sequences (SSU) for phylogenetic analysis and large subunit (LSU) sequences for phylogeny and DNA-based identification. Phylogenetic analysis reveals that within the Hypocreales, there are two major clusters containing multiple Acremonium species. One clade contains Acremonium sclerotigenum, the genus Emericellopsis, and the genus Geosmithia as prominent elements. The second clade contains the genera Gliomastix sensu stricto and Bionectria. In addition, there are numerous smaller clades plus two multi-species clades, one containing Acremonium strictum and the type species of the genus Sarocladium, and, as seen in the combined SSU/LSU analysis, one associated subclade containing Acremonium breve and related species plus Acremonium curvulum and related species. This sequence information allows the revision of three genera. Gliomastix is revived for five species, G. murorum, G. polychroma, G. tumulicola, G. roseogrisea, and G. masseei. Sarocladium is extended to include all members of the phylogenetically distinct A. strictum clade including the medically important A. kiliense and the protective maize endophyte A. zeae. Also included in Sarocladium are members of the phylogenetically delimited Acremonium bacillisporum clade, closely linked to the A. strictum clade. The genus Trichothecium is revised following the principles of unitary nomenclature based on the oldest valid anamorph or teleomorph name, and new combinations are made in Trichothecium for the tightly interrelated Acremonium crotocinigenum, Spicellum roseum, and teleomorph Leucosphaerina indica. Outside the Hypocreales, numerous Acremonium-like species fall into the Plectosphaerellaceae, and A. atrogriseum falls into the Cephalothecaceae. PMID:21523192

Event-triggered attitude control of spacecraft

NASA Astrophysics Data System (ADS)

Wu, Baolin; Shen, Qiang; Cao, Xibin

2018-02-01

The problem of spacecraft attitude stabilization control system with limited communication and external disturbances is investigated based on an event-triggered control scheme. In the proposed scheme, information of attitude and control torque only need to be transmitted at some discrete triggered times when a defined measurement error exceeds a state-dependent threshold. The proposed control scheme not only guarantees that spacecraft attitude control errors converge toward a small invariant set containing the origin, but also ensures that there is no accumulation of triggering instants. The performance of the proposed control scheme is demonstrated through numerical simulation.

Description of the physical environment an coal-mining history of West-Central Indiana, with emphasis on six small watersheds

USGS Publications Warehouse

Martin, Jeffrey D.; Crawford, Charles G.; Duwelius, Richard F.; Renn, Danny E.

1990-01-01

Pond Creek and the unnamed tributary to Big Branch are streams that drain mined and unreclaimed watersheds. Approximately one-half of the Pond Creek watershed is unmined, agricultural land. Soils are very well-drained shaly silty loams that have formed or' steeply sloping spoil banks. Both watersheds contain numerous impoundments of water and have enclosed areas that do not contribute surface runoff to streamflow. The ridges of mine spoil are covered with pine trees, but much of the soil surface is devoid of vegetation.

Physics, mathematics and numerics of particle adsorption on fluid interfaces

NASA Astrophysics Data System (ADS)

Schmuck, Markus; Pavliotis, Grigorios A.; Kalliadasis, Serafim

2012-11-01

We study two arbitrary immiscible fuids where one phase contains small particles of the size of the interface and smaller. We primarily focus on charge-free particles with wetting characteristics described by the contact angle formed at the interface between the two phases and the particles. Based on the experimental observation that particles are adsorbed on the interface to reduce the interfacial energy and hence the surface tension as well, we formulate a free-energy functional that accounts for these physical effects. Using elements from calculus of variations and formal gradient flow theory, we derive partial differential equations describing the location of the interface and the density of the particles in the fluid phases. Via numerical experiments we analyse the time evolution of the surface tension, the particle concentration, and the free energy over time and reflect basic experimentally observed phenomena.

Relativistic nuclear magnetic resonance J-coupling with ultrasoft pseudopotentials and the zeroth-order regular approximation

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

Green, Timothy F. G., E-mail: tim.green@materials.ox.ac.uk; Yates, Jonathan R., E-mail: jonathan.yates@materials.ox.ac.uk

2014-06-21

We present a method for the first-principles calculation of nuclear magnetic resonance (NMR) J-coupling in extended systems using state-of-the-art ultrasoft pseudopotentials and including scalar-relativistic effects. The use of ultrasoft pseudopotentials is allowed by extending the projector augmented wave (PAW) method of Joyce et al. [J. Chem. Phys. 127, 204107 (2007)]. We benchmark it against existing local-orbital quantum chemical calculations and experiments for small molecules containing light elements, with good agreement. Scalar-relativistic effects are included at the zeroth-order regular approximation level of theory and benchmarked against existing local-orbital quantum chemical calculations and experiments for a number of small molecules containing themore » heavy row six elements W, Pt, Hg, Tl, and Pb, with good agreement. Finally, {sup 1}J(P-Ag) and {sup 2}J(P-Ag-P) couplings are calculated in some larger molecular crystals and compared against solid-state NMR experiments. Some remarks are also made as to improving the numerical stability of dipole perturbations using PAW.« less

[Gene transfer agent--a novel and widespread occurrence mechanism of gene exchange in ocean-a review].

PubMed

Cai, Haiyuan

2012-01-01

Gene Transfer Agent (GTA) particles are released by bacteria and resemble small, tailed bacteriophages. GTA particles contain small, random pieces of host DNA rather than GTA structural genes or a phage genome. Gene transfer mediated by GTA is efficient and species specific based on knowledge of currently best studied GTAs produced by 4 anaerobes. Genome sequencing projects have revealed a remarkable distribution of GTA gene clusters in the genomes of marine bacterioplankton, implying GTA may be an important mechanism for horizontal gene transfer in ocean. On basis of characterization of the 4 best studied GTAs, this review described GTAs released by numerically dominant marine bacteria, discussed their properties that were important for horizontal gene transfer in ocean, and gave future perspectives to advance GTA research.

First-order reactant in homogeneous turbulence before the final period of decay. [contaminant fluctuations in chemical reaction

NASA Technical Reports Server (NTRS)

Kumar, P.; Patel, S. R.

1974-01-01

A method is described for studying theoretically the concentration fluctuations of a dilute contaminate undergoing a first-order chemical reaction. The method is based on Deissler's (1958) theory for homogeneous turbulence for times before the final period, and it follows the approach used by Loeffler and Deissler (1961) to study temperature fluctuations in homogeneous turbulence. Four-point correlation equations are obtained; it is assumed that terms containing fifth-order correlation are very small in comparison with those containing fourth-order correlations, and can therefore be neglected. A spectrum equation is obtained in a form which can be solved numerically, yielding the decay law for the concentration fluctuations in homogeneous turbulence for the period much before the final period of decay.

Use of the routing procedure to study dye and gas transport in the West Fork Trinity River, Texas

USGS Publications Warehouse

Jobson, Harvey E.; Rathbun, R.E.

1984-01-01

Rhodamine-WT dye, ethylene, and propane were injected at three sites along a 21.6-kilometer reach of the West Fork Trinity River below Fort Worth, Texas. Complete dye concentration versus time curves and peak gas concentrations were measured at three cross sections below each injection. The peak dye concentrations were located and samples were collected at about three-hour intervals for as many as six additional cross sections. These data were analyzed to determine the longitudinal dispersion coefficients as well as the gas desorption coefficients using both standard techniques and a numerical routing procedure. The routing procedure, using a Lagrangian transport model to minimize numerical dispersion, provided better estimates of the dispersion coefficient than did the method of moments. At a steady flow of about 0.76 m2/s, the dispersion coefficient varied from about 0.7 m2/s in a reach contained within a single deep pool to about 2.0 m2/s in a reach containing riffles and small pools. The bulk desorption coefficients computed using the routing procedure and the standard peak method were essentially the same. The liquid film coefficient could also be obtained using the routing procedure. Both the bulk desorption coefficient and the liquid film coefficient were much smaller in the pooled reach than in the reaches containing riffles.

Numerical Optimization of Density Functional Tight Binding Models: Application to Molecules Containing Carbon, Hydrogen, Nitrogen, and Oxygen

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

Krishnapriyan, A.; Yang, P.; Niklasson, A. M. N.

New parametrizations for semiempirical density functional tight binding (DFTB) theory have been developed by the numerical optimization of adjustable parameters to minimize errors in the atomization energy and interatomic forces with respect to ab initio calculated data. Initial guesses for the radial dependences of the Slater- Koster bond integrals and overlap integrals were obtained from minimum basis density functional theory calculations. The radial dependences of the pair potentials and the bond and overlap integrals were represented by simple analytic functions. The adjustable parameters in these functions were optimized by simulated annealing and steepest descent algorithms to minimize the value ofmore » an objective function that quantifies the error between the DFTB model and ab initio calculated data. The accuracy and transferability of the resulting DFTB models for the C, H, N, and O system were assessed by comparing the predicted atomization energies and equilibrium molecular geometries of small molecules that were not included in the training data from DFTB to ab initio data. The DFTB models provide accurate predictions of the properties of hydrocarbons and more complex molecules containing C, H, N, and O.« less

Numerical Optimization of Density Functional Tight Binding Models: Application to Molecules Containing Carbon, Hydrogen, Nitrogen, and Oxygen

DOE PAGES

Krishnapriyan, A.; Yang, P.; Niklasson, A. M. N.; ...

2017-10-17

New parametrizations for semiempirical density functional tight binding (DFTB) theory have been developed by the numerical optimization of adjustable parameters to minimize errors in the atomization energy and interatomic forces with respect to ab initio calculated data. Initial guesses for the radial dependences of the Slater- Koster bond integrals and overlap integrals were obtained from minimum basis density functional theory calculations. The radial dependences of the pair potentials and the bond and overlap integrals were represented by simple analytic functions. The adjustable parameters in these functions were optimized by simulated annealing and steepest descent algorithms to minimize the value ofmore » an objective function that quantifies the error between the DFTB model and ab initio calculated data. The accuracy and transferability of the resulting DFTB models for the C, H, N, and O system were assessed by comparing the predicted atomization energies and equilibrium molecular geometries of small molecules that were not included in the training data from DFTB to ab initio data. The DFTB models provide accurate predictions of the properties of hydrocarbons and more complex molecules containing C, H, N, and O.« less

Measurement and numerical simulation of a small centrifugal compressor characteristics at small or negative flow rate

NASA Astrophysics Data System (ADS)

Tsukamoto, Kaname; Okada, Mizuki; Inokuchi, Yuzo; Yamasaki, Nobuhiko; Yamagata, Akihiro

2017-04-01

For centrifugal compressors used in automotive turbochargers, the extension of the surge margin is demanded because of lower engine speed. In order to estimate the surge line exactly, it is required to acquire the compressor characteristics at small or negative flow rate. In this paper, measurement and numerical simulation of the characteristics at small or negative flow rate are carried out. In the measurement, an experimental facility with a valve immediately downstream of the compressor is used to suppress the surge. In the numerical work, a new boundary condition that specifies mass flow rate at the outlet boundary is used to simulate the characteristics around the zero flow rate region. Furthermore, flow field analyses at small or negative flow rate are performed with the numerical results. The separated and re-circulated flow fields are investigated by visualization to identify the origin of losses.

Comparative Analysis of Leaf Trichome Structure and Composition of Epicuticular Flavonoids in Finnish Birch Species

PubMed Central

VALKAMA, ELENA; SALMINEN, JUHA‐PEKKA; KORICHEVA, JULIA; PIHLAJA, KALEVI

2003-01-01

The morphology, ultrastructure, density and distribution of trichomes on leaves of Betula pendula, B. pubescens ssp. pubescens, B. pubescens ssp. czerepanovii and B. nana were examined by means of light, scanning and transmission electron microscopy. The composition of flavonoids in ethanolic leaf surface extracts was analysed by high pressure liquid chromatography. All taxa examined contained both glandular and non‐glandular trichomes (short and/or long hairs) but differed from each other in trichome ultrastructure, density and location on the leaf. Leaves of B. pubescens were more hairy than those of B. pendula, but the latter species had a higher density of glandular trichomes. Of the two subspecies of B. pubescens, leaves of ssp. pubescens had more short hairs on the leaf surface and four times the density of glandular trichomes of leaves of ssp. czerepanovii, whereas, in the latter subspecies, short hairs occurred largely on leaf veins, as in B. nana. The glandular trichomes were peltate glands, consisting of medullar and cortical cells, which differed structurally. Cortical cells possessed numerous small, poorly developed plastids and small vacuoles, whereas medullar cells had several large plastids with well‐developed thylakoid systems and fewer vacuoles. In B. pubescens subspecies, vacuoles of the glandular cells contained osmiophilic deposits, which were probably phenolic, whereas in B. pendula, vacuoles of glandular trichomes were characterized by the presence of numerous myelin‐like membranes. The composition of epicuticular flavonoids also differed among species. The two subspecies of B. pubescens and B. nana shared the same 12 compounds, but five of these occurred only in trace amounts in B. nana. Leaf surface extracts of B. pendula contained just six flavonoids, three of which occurred only in this species. In summary, the structure, density and distribution of leaf trichomes and the composition of epicuticular flavonoids represent good taxonomic markers for Finnish birch species. PMID:12714363

Social and natural sciences differ in their research strategies, adapted to work for different knowledge landscapes.

PubMed

Jaffe, Klaus

2014-01-01

Do different fields of knowledge require different research strategies? A numerical model exploring different virtual knowledge landscapes, revealed two diverging optimal search strategies. Trend following is maximized when the popularity of new discoveries determine the number of individuals researching it. This strategy works best when many researchers explore few large areas of knowledge. In contrast, individuals or small groups of researchers are better in discovering small bits of information in dispersed knowledge landscapes. Bibliometric data of scientific publications showed a continuous bipolar distribution of these strategies, ranging from natural sciences, with highly cited publications in journals containing a large number of articles, to the social sciences, with rarely cited publications in many journals containing a small number of articles. The natural sciences seem to adapt their research strategies to landscapes with large concentrated knowledge clusters, whereas social sciences seem to have adapted to search in landscapes with many small isolated knowledge clusters. Similar bipolar distributions were obtained when comparing levels of insularity estimated by indicators of international collaboration and levels of country-self citations: researchers in academic areas with many journals such as social sciences, arts and humanities, were the most isolated, and that was true in different regions of the world. The work shows that quantitative measures estimating differences between academic disciplines improve our understanding of different research strategies, eventually helping interdisciplinary research and may be also help improve science policies worldwide.

Numerical Study of Pyrolysis of Biomass in Fluidized Beds

NASA Technical Reports Server (NTRS)

Bellan, Josette; Lathouwers, Danny

2003-01-01

A report presents a numerical-simulation study of pyrolysis of biomass in fluidized-bed reactors, performed by use of the mathematical model described in Model of Fluidized Bed Containing Reacting Solids and Gases (NPO-30163), which appears elsewhere in this issue of NASA Tech Briefs. The purpose of the study was to investigate the effect of various operating conditions on the efficiency of production of condensable tar from biomass. The numerical results indicate that for a fixed particle size, the fluidizing-gas temperature is the foremost parameter that affects the tar yield. For the range of fluidizing-gas temperatures investigated, and under the assumption that the pyrolysis rate exceeds the feed rate, the optimum steady-state tar collection was found to occur at 750 K. In cases in which the assumption was not valid, the optimum temperature for tar collection was found to be only slightly higher. Scaling up of the reactor was found to exert a small negative effect on tar collection at the optimal operating temperature. It is also found that slightly better scaling is obtained by use of shallower fluidized beds with greater fluidization velocities.

Numerical simulation of systems of shear bands in ductile metal with inclusions

NASA Astrophysics Data System (ADS)

Plohr, Jeeyeon

2017-06-01

We develop a method for numerical simulations of high strain-rate loading of mesoscale samples of ductile metal with inclusions. Because of its small-scale inhomogeneity, the composite material is prone to localized shear deformation. This method employs the Generalized Method of Cells to ensure that the micro mechanical behavior of the metal and inclusions is reflected properly in the behavior of the composite at the mesoscale. To find the effective plastic strain rate when shear bands are present, we extend and apply the analytic and numerical analysis of shear bands of Glimm, Plohr, and Sharp. Our tests of the method focus on the stress/strain response in uniaxial-strain flow, both compressive and tensile, of depleted uranium metal containing silicon carbide inclusions. In results, we verify the elevated temperature and thermal softening at shear bands in our simulations of pure DU and DU/SiC composites. We also note that in composites, due the asymmetry caused by the inclusions, shear band form at different times in different subcells. In particular, in the subcells near inclusions, shear band form much earlier than they do in pure DU.

Powder agglomeration in a microgravity environment

NASA Technical Reports Server (NTRS)

Cawley, James D.

1994-01-01

This is the final report for NASA Grant NAG3-755 entitled 'Powder Agglomeration in a Microgravity Environment.' The research program included both two types of numerical models and two types of experiments. The numerical modeling included the use of Monte Carlo type simulations of agglomerate growth including hydrodynamic screening and molecular dynamics type simulations of the rearrangement of particles within an agglomerate under a gravitational field. Experiments included direct observation of the agglomeration of submicron alumina and indirect observation, using small angle light scattering, of the agglomeration of colloidal silica and aluminum monohydroxide. In the former class of experiments, the powders were constrained to move on a two-dimensional surface oriented to minimize the effect of gravity. In the latter, some experiments involved mixture of suspensions containing particles of opposite charge which resulted in agglomeration on a very short time scale relative to settling under gravity.

Ultrastructure of the surface structures and haptor of Empleurosoma pyriforme (Ancyrocephalinae; Monopisthocotylea: Monogenea) from the gills of the teleost fish Therapon jarbua.

PubMed

Ramasamy, P; Brennan, G P

2000-02-01

Infections with Empleurosoma pyriforme occur between successive secondary gill lamellae on both sides of the primary lamella of Therapon jarbua. The haptoral disc bears two pairs of anchors and a pair of connecting transverse bars. The attachment of the parasite to the host gill causes inflammation, erosion and degeneration of the gill epithelia. The ventral anchors consist of an inner core of irregularly arranged, electron-dense fibrils and a smooth outer core of electron-lucent fibrils, whereas the surface of the dorsal anchors is ridged. Both the dorsal and the ventral anchors may be extended or withdrawn. The connecting transverse bars consist of longitudinally arranged fibrils in an electron-dense matrix, whereas the tendons consist of fibrils, supported in a less electron-dense matrix, which interconnect the anchor erector-protractor muscles and the haptor muscles. Two types of perikarya are present. The less common type contain large multivesicular bodies and small electron-dense granules and are located only in the haptor region. The second and more common perikarya are present throughout the body surface. The cytoplasmic syncytium contains numerous electron-dense granules and electron-lucent vesicles. Beneath the syncytium, unicellular epidermal gland cells contain electron-dense granules. Neurones containing numerous electron-dense vesicles are present in the haptor region. Uniciliate presumed sensory receptors are distributed over the body surface. Groups of ciliated sensory structures are present in the forebody. Ciliated and non-ciliated presumed sensory receptors are present in the sleeve cavity of the anchors, on the haptor and in the vicinity of the oral apertures.

Effects of dust size distribution on dust acoustic waves in two-dimensional unmagnetized dusty plasma

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

He Guangjun; Duan Wenshan; Tian Duoxiang

2008-04-15

For unmagnetized dusty plasma with many different dust grain species containing both hot isothermal electrons and ions, both the linear dispersion relation and the Kadomtsev-Petviashvili equation for small, but finite amplitude dust acoustic waves are obtained. The linear dispersion relation is investigated numerically. Furthermore, the variations of amplitude, width, and propagation velocity of the nonlinear solitary wave with an arbitrary dust size distribution function are studied as well. Moreover, both the power law distribution and the Gaussian distribution are approximately simulated by using appropriate arbitrary dust size distribution functions.

BRYNTRN: A baryon transport model

NASA Technical Reports Server (NTRS)

Wilson, John W.; Townsend, Lawrence W.; Nealy, John E.; Chun, Sang Y.; Hong, B. S.; Buck, Warren W.; Lamkin, S. L.; Ganapol, Barry D.; Khan, Ferdous; Cucinotta, Francis A.

1989-01-01

The development of an interaction data base and a numerical solution to the transport of baryons through an arbitrary shield material based on a straight ahead approximation of the Boltzmann equation are described. The code is most accurate for continuous energy boundary values, but gives reasonable results for discrete spectra at the boundary using even a relatively coarse energy grid (30 points) and large spatial increments (1 cm in H2O). The resulting computer code is self-contained, efficient and ready to use. The code requires only a very small fraction of the computer resources required for Monte Carlo codes.

Comparison of numerical simulation and experimental data for steam-in-place sterilization

NASA Technical Reports Server (NTRS)

Young, Jack H.; Lasher, William C.

1993-01-01

A complex problem involving convective flow of a binary mixture containing a condensable vapor and noncondensable gas in a partially enclosed chamber was modelled and results compared to transient experimental values. The finite element model successfully predicted transport processes in dead-ended tubes with inside diameters of 0.4 to 1.0 cm. When buoyancy driven convective flow was dominant, temperature and mixture compositions agreed with experimental data. Data from 0.4 cm tubes indicate diffusion to be the primary air removal method in small diameter tubes and the diffusivity value in the model to be too large.

Immunoglobulin-containing cells in the intestinal mucosa and immunoglobulins in the intestinal juice in children

PubMed Central

Savilahti, E.

1972-01-01

The numbers of immunoglobulin-containing cells in the mucosae of the small intestine and rectum were counted by a direct immunofluorescence technique in biopsy specimens from children. Immunoglobulins in the intestinal juice of the same patients were quantified by electroimmunodiffusion. In all biopsy specimens IgA-containing cells predominated. These cells were more numerous in the specimens from children over 2 years of age than in those of younger ones. The cells seemed to be fairly evenly distributed along the intestinal tract. The number of IgM-containing cells did not change with age in the group studied. In the intestinal juice the mean content of IgA was higher than that of the other immunoglobulins. More IgM and less IgA were found in the juice of infants under 2 years of age than in that of older children. The results suggest that quantitatively the IgA-producing system of the gut is not fully developed in infancy, whereas the reverse is true for the cells producing IgM. PMID:4625398

Inflation from periodic extra dimensions

NASA Astrophysics Data System (ADS)

Higaki, Tetsutaro; Tatsuta, Yoshiyuki

2017-07-01

We discuss a realization of a small field inflation based on string inspired supergravities. In theories accompanying extra dimensions, compactification of them with small radii is required for realistic situations. Since the extra dimension can have a periodicity, there will appear (quasi-)periodic functions under transformations of moduli of the extra dimensions in low energy scales. Such a periodic property can lead to a UV completion of so-called multi-natural inflation model where inflaton potential consists of a sum of multiple sinusoidal functions with a decay constant smaller than the Planck scale. As an illustration, we construct a SUSY breaking model, and then show that such an inflaton potential can be generated by a sum of world sheet instantons in intersecting brane models on extra dimensions containing orbifold. We show also predictions of cosmic observables by numerical analyzes.

Inflation from periodic extra dimensions

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

Higaki, Tetsutaro; Tatsuta, Yoshiyuki, E-mail: thigaki@rk.phys.keio.ac.jp, E-mail: y_tatsuta@akane.waseda.jp

We discuss a realization of a small field inflation based on string inspired supergravities. In theories accompanying extra dimensions, compactification of them with small radii is required for realistic situations. Since the extra dimension can have a periodicity, there will appear (quasi-)periodic functions under transformations of moduli of the extra dimensions in low energy scales. Such a periodic property can lead to a UV completion of so-called multi-natural inflation model where inflaton potential consists of a sum of multiple sinusoidal functions with a decay constant smaller than the Planck scale. As an illustration, we construct a SUSY breaking model, andmore » then show that such an inflaton potential can be generated by a sum of world sheet instantons in intersecting brane models on extra dimensions containing orbifold. We show also predictions of cosmic observables by numerical analyzes.« less

Iberian fish records in the vertebrate collection of the Museum of Zoology of the University of Navarra

PubMed Central

Rodeles, Amaia A.; Galicia, David; Miranda, Rafael

2016-01-01

The study of freshwater fish species biodiversity and community composition is essential for understanding river systems, the effects of human activities on rivers, and the changes these animals face. Conducting this type of research requires quantitative information on fish abundance, ideally with long-term series and fish body measurements. This Data Descriptor presents a collection of 12 datasets containing a total of 146,342 occurrence records of 41 freshwater fish species sampled in 233 localities of various Iberian river basins. The datasets also contain 148,749 measurement records (length and weight) for these fish. Data were collected in different sampling campaigns (from 1992 to 2015). Eleven datasets represent large projects conducted over several years, and another combines small sampling campaigns. The Iberian Peninsula contains high fish biodiversity, with numerous endemic species threatened by various menaces, such as water extraction and invasive species. These data may support the development of large biodiversity conservation studies. PMID:27727236

Design of chemical space networks on the basis of Tversky similarity

NASA Astrophysics Data System (ADS)

Wu, Mengjun; Vogt, Martin; Maggiora, Gerald M.; Bajorath, Jürgen

2016-01-01

Chemical space networks (CSNs) have been introduced as a coordinate-free representation of chemical space. In CSNs, nodes represent compounds and edges pairwise similarity relationships. These network representations are mostly used to navigate sections of biologically relevant chemical space. Different types of CSNs have been designed on the basis of alternative similarity measures including continuous numerical similarity values or substructure-based similarity criteria. CSNs can be characterized and compared on the basis of statistical concepts from network science. Herein, a new CSN design is introduced that is based upon asymmetric similarity assessment using the Tversky coefficient and termed TV-CSN. Compared to other CSNs, TV-CSNs have unique features. While CSNs typically contain separate compound communities and exhibit small world character, many TV-CSNs are also scale-free in nature and contain hubs, i.e., extensively connected central compounds. Compared to other CSNs, these hubs are a characteristic of TV-CSN topology. Hub-containing compound communities are of particular interest for the exploration of structure-activity relationships.

Iberian fish records in the vertebrate collection of the Museum of Zoology of the University of Navarra.

PubMed

Rodeles, Amaia A; Galicia, David; Miranda, Rafael

2016-10-11

The study of freshwater fish species biodiversity and community composition is essential for understanding river systems, the effects of human activities on rivers, and the changes these animals face. Conducting this type of research requires quantitative information on fish abundance, ideally with long-term series and fish body measurements. This Data Descriptor presents a collection of 12 datasets containing a total of 146,342 occurrence records of 41 freshwater fish species sampled in 233 localities of various Iberian river basins. The datasets also contain 148,749 measurement records (length and weight) for these fish. Data were collected in different sampling campaigns (from 1992 to 2015). Eleven datasets represent large projects conducted over several years, and another combines small sampling campaigns. The Iberian Peninsula contains high fish biodiversity, with numerous endemic species threatened by various menaces, such as water extraction and invasive species. These data may support the development of large biodiversity conservation studies.

Internal Flow of Contra-Rotating Small Hydroturbine at Off- Design Flow Rates

NASA Astrophysics Data System (ADS)

SHIGEMITSU, Toru; TAKESHIMA, Yasutoshi; OGAWA, Yuya; FUKUTOMI, Junichiro

2016-11-01

Small hydropower generation is one of important alternative energy, and enormous potential lie in the small hydropower. However, efficiency of small hydroturbines is lower than that of large one. Then, there are demands for small hydroturbines to keep high performance in wide flow rate range. Therefore, we adopted contra-rotating rotors, which can be expected to achieve high performance. In this research, performance of the contra-rotating small hydroturbine with 60mm casing diameter was investigated by an experiment and numerical analysis. Efficiency of the contra-rotating small hydroturbine was high in pico-hydroturbine and high efficiency could be kept in wide flow rate range, however the performance of a rear rotor decreased significantly in partial flow rates. Then, internal flow condition, which was difficult to measure experimentally, was investigated by the numerical flow analysis. Then, a relation between the performance and internal flow condition was considered by the numerical analysis result.

Numerical modeling of an enhanced very early time electromagnetic (VETEM) prototype system

USGS Publications Warehouse

Cui, T.J.; Chew, W.C.; Aydiner, A.A.; Wright, D.L.; Smith, D.V.; Abraham, J.D.

2000-01-01

In this paper, two numerical models are presented to simulate an enhanced very early time electromagnetic (VETEM) prototype system, which is used for buried-object detection and environmental problems. Usually, the VETEM system contains a transmitting loop antenna and a receiving loop antenna, which run on a lossy ground to detect buried objects. In the first numerical model, the loop antennas are accurately analyzed using the Method of Moments (MoM) for wire antennas above or buried in lossy ground. Then, Conjugate Gradient (CG) methods, with the use of the fast Fourier transform (FFT) or MoM, are applied to investigate the scattering from buried objects. Reflected and scattered magnetic fields are evaluated at the receiving loop to calculate the output electric current. However, the working frequency for the VETEM system is usually low and, hence, two magnetic dipoles are used to replace the transmitter and receiver in the second numerical model. Comparing these two models, the second one is simple, but only valid for low frequency or small loops, while the first modeling is more general. In this paper, all computations are performed in the frequency domain, and the FFT is used to obtain the time-domain responses. Numerical examples show that simulation results from these two models fit very well when the frequency ranges from 10 kHz to 10 MHz, and both results are close to the measured data.

Numerical viscosity and the entropy condition for conservative difference schemes

NASA Technical Reports Server (NTRS)

Tadmor, E.

1983-01-01

Consider a scalar, nonlinear conservative difference scheme satisfying the entropy condition. It is shown that difference schemes containing more numerical viscosity will necessarily converge to the unique, physically relevant weak solution of the approximated conservation equation. In particular, entropy satisfying convergence follows for E schemes - those containing more numerical viscosity than Godunov's scheme.

Small reservoir distribution, rate of construction, and uses in the upper and middle Chattahoochee basins of the Georgia Piedmont, USA, 1950-2010

USGS Publications Warehouse

Ignatius, Amber R.; Jones, John W.

2014-01-01

Construction of small reservoirs affects ecosystem processes in numerous ways including fragmenting stream habitat, altering hydrology, and modifying water chemistry. While the upper and middle Chattahoochee River basins within the Southeastern United States Piedmont contain few natural lakes, they have a high density of small reservoirs (more than 7500 small reservoirs in the nearly 12,000 km2 basin). Policymakers and water managers in the region have little information about small reservoir distribution, uses, or the cumulative inundation of land cover caused by small reservoir construction. Examination of aerial photography reveals the spatiotemporal patterns and extent of small reservoir construction from 1950 to 2010. Over that 60 year timeframe, the area inundated by water increased nearly six fold (from 19 reservoirs covering 0.16% of the study area in 1950 to 329 reservoirs covering 0.95% of the study area in 2010). While agricultural practices were associated with reservoir creation from 1950 to 1970, the highest rates of reservoir construction occurred during subsequent suburban development between 1980 and 1990. Land cover adjacent to individual reservoirs transitioned over time through agricultural abandonment, land reforestation, and conversion to development during suburban expansion. The prolific rate of ongoing small reservoir creation, particularly in newly urbanizing regions and developing counties, necessitates additional attention from watershed managers and continued scientific research into cumulative environmental impacts at the watershed scale.

A Large Scale Biorational Approach Using Bacillus thuringiensis israeliensis (Strain AM65-52) for Managing Aedes aegypti Populations to Prevent Dengue, Chikungunya and Zika Transmission

PubMed Central

Pruszynski, Catherine A.; Hribar, Lawrence J.; Mickle, Robert; Leal, Andrea L.

2017-01-01

Background Aedes aegypti is a container-inhabiting mosquito and a vector of dengue, chikungunya, and Zika viruses. In 2009 several cases of autochthonous dengue transmission were reported in Key West, Florida, USA prompting a comprehensive response to control A. aegypti. In Key West, larvae of this mosquito develop in containers around human habitations which can be numerous and labor intensive to find and treat. Aerial applications of larvicide covering large areas in a short time can be an efficient and economical method to control A. aegypti. Bacillus thuringiensis israelensis (Bti) is a bacterial larvicide which is highly target specific and appropriate for wide area spraying over urban areas, but to date, there are no studies that evaluate aerial spraying of Bti to control container mosquitoes like A. aegypti. Methodology This paper examines the effectiveness of aerial larvicide applications using VectoBac® WG, a commercially available Bti formulation, for A. aegypti control in an urban setting in the USA. Droplet characteristics and spray drop deposition were evaluated in Key West, Florida, USA. The mortality of A. aegypti in containers placed under canopy in an urban environment was also evaluated. Efficacy of multiple larvicide applications on adult female A. aegypti population reduction was compared between an untreated control and treatment site. Conclusions Droplet characteristics showed that small droplets can penetrate through dense canopy to reach small containers. VectoBac WG droplets reached small containers under heavy canopy in sufficient amounts to cause > 55% mortality on all application days and >90% mortality on 3 of 5 application days while controls had <5% mortality. Aerial applications of VectoBac WG caused significant decrease in adult female populations throughout the summer and during the 38th week (last application) the difference in adult female numbers between untreated and treated sites was >50%. Aerial larvicide applications using VectoBac WG can cover wide areas in a short period of time and can be effective in controlling A. aegypti and reducing A. aegypti-borne transmission in urban areas similar to Key West, Florida, USA. PMID:28199323

Sampling--how big a sample?

PubMed

Aitken, C G

1999-07-01

It is thought that, in a consignment of discrete units, a certain proportion of the units contain illegal material. A sample of the consignment is to be inspected. Various methods for the determination of the sample size are compared. The consignment will be considered as a random sample from some super-population of units, a certain proportion of which contain drugs. For large consignments, a probability distribution, known as the beta distribution, for the proportion of the consignment which contains illegal material is obtained. This distribution is based on prior beliefs about the proportion. Under certain specific conditions the beta distribution gives the same numerical results as an approach based on the binomial distribution. The binomial distribution provides a probability for the number of units in a sample which contain illegal material, conditional on knowing the proportion of the consignment which contains illegal material. This is in contrast to the beta distribution which provides probabilities for the proportion of a consignment which contains illegal material, conditional on knowing the number of units in the sample which contain illegal material. The interpretation when the beta distribution is used is much more intuitively satisfactory. It is also much more flexible in its ability to cater for prior beliefs which may vary given the different circumstances of different crimes. For small consignments, a distribution, known as the beta-binomial distribution, for the number of units in the consignment which are found to contain illegal material, is obtained, based on prior beliefs about the number of units in the consignment which are thought to contain illegal material. As with the beta and binomial distributions for large samples, it is shown that, in certain specific conditions, the beta-binomial and hypergeometric distributions give the same numerical results. However, the beta-binomial distribution, as with the beta distribution, has a more intuitively satisfactory interpretation and greater flexibility. The beta and the beta-binomial distributions provide methods for the determination of the minimum sample size to be taken from a consignment in order to satisfy a certain criterion. The criterion requires the specification of a proportion and a probability.

Asteroidal Differentiation Processes Deduced from Ultramafic Achondrite Ureilite Meteorites

NASA Technical Reports Server (NTRS)

Downes, Hilary; Mittlefehldt, David W.; Hudson, Pierre; Romanek, Christopher S.; Franchi, Ian

2006-01-01

Ureilites are the second largest achondrite group. They are ultramafic achondrites that have experienced igneous processing whilst retaining some degree of nebula-derived chemical heterogeneity. They differ from other achondrites in that they contain abundant carbon and their oxygen isotope compositions are very heterogeneous and similar to those of the carbonaceous chondrite anhydrous mineral line. Their carbonaceous nature and some compositional characteristics indicative of nebular origin suggest that they are primitive materials that form a link between nebular processes and early periods of planetesimal accretion. However, despite numerous studies, the exact origin of ureilites remains unclear. Current opinion is that they represent the residual mantle of an asteroid that underwent silicate and Fe-Ni-S partial melting and melt removal. Recent studies of short-lived chronometers indicate that the parent asteroid of the ureilites differentiated very early in the history of the Solar System. Therefore, they contain important information about processes that formed small rocky planetesimals in the early Solar System. In effect, they form a bridge between nebula processes and differentiation in small planetesimals prior to accretion into larger planets and so a correct interpretation of ureilite petrogenesis is essential for understanding this critical step.

Cytoarchitecture of Caudiverbera caudiverbera stage VI oocytes: a light and electron microscope study.

PubMed

Dabiké, M; Preller, A

1999-06-01

The general characteristics and salient features of the full-grown stage VI Caudiverbera caudiverbera oocyte at the light and electron microscopy level are described. The oocyte is a huge cell with radial symmetry and distinct polarity. A black animal hemisphere, rich in pigment granules and containing the nucleus, is clearly distinguished from the unpigmented white-yellowish vegetal hemisphere. The cell is surrounded by a highly invaginated plasma membrane, with numerous microvilli. The cortex underlying the plasma membrane contains cortical and pigment granules, mitochondria, rough endoplasmic reticulum and coated vesicles. Cytoskeletal components, such as actin filaments and microtubules, are also found in this region. The predominant structures, distributed throughout the cell, are the yolk platelets, which show a gradient in size with small platelets in the animal half and very large ones in the vegetal zone. Mitochondria are also very abundant in both hemispheres and clouds of these organelles are found in the perinuclear region, frequently associated with microtubules. Developed Golgi complexes are present in the cytoplasm and occasionally, annulate lamellae appear towards the inner zones. The nucleus is a large structure containing numerous nucleoli. The nuclear envelope is highly invaginated, especially at the side facing the vegetal pole. It is regularly perforated by large nuclear pores. Our results show that the structural organization of Caudiverbera oocytes, although similar to that of other amphibian oocytes, differs from them especially concerning the spatial distribution of several structural components.

Prediction of dynamic and aerodynamic characteristics of the centrifugal fan with forward curved blades

NASA Astrophysics Data System (ADS)

Polanský, Jiří; Kalmár, László; Gášpár, Roman

2013-12-01

The main aim of this paper is determine the centrifugal fan with forward curved blades aerodynamic characteristics based on numerical modeling. Three variants of geometry were investigated. The first, basic "A" variant contains 12 blades. The geometry of second "B" variant contains 12 blades and 12 semi-blades with optimal length [1]. The third, control variant "C" contains 24 blades without semi-blades. Numerical calculations were performed by CFD Ansys. Another aim of this paper is to compare results of the numerical simulation with results of approximate numerical procedure. Applied approximate numerical procedure [2] is designated to determine characteristics of the turbulent flow in the bladed space of a centrifugal-flow fan impeller. This numerical method is an extension of the hydro-dynamical cascade theory for incompressible and inviscid fluid flow. Paper also partially compares results from the numerical simulation and results from the experimental investigation. Acoustic phenomena observed during experiment, during numerical simulation manifested as deterioration of the calculation stability, residuals oscillation and thus also as a flow field oscillation. Pressure pulsations are evaluated by using frequency analysis for each variant and working condition.

Isolation and characterization of multivesicular bodies from rat hepatocytes: an organelle distinct from secretory vesicles of the Golgi apparatus

PubMed Central

1985-01-01

Hepatocytes of estradiol-treated rats, which express many low density lipoprotein receptors, rapidly accumulate intravenously injected low density lipoprotein in multivesicular bodies (MVBs). We have isolated MVBs and Golgi apparatus fractions from livers of estradiol-treated rats. MVB fractions were composed mainly of large vesicles, approximately 0.55 micron diam, filled with remnantlike very low density lipoproteins, known to be taken up into hepatocytes by receptor- mediated endocytosis. MVBs also contained numerous small vesicles, 0.05- 0.07 micron in diameter, and had two types of appendages: one fingerlike and electron dense and the other saclike and electron lucent. MVBs contained little galactosyltransferase or arylsulfatase activity, and content lipoproteins were largely intact. Very low density lipoproteins from Golgi fractions, which are derived to a large extent from secretory vesicles, were larger than those of MVB fractions and contained newly synthesized triglycerides. Membranes of MVBs contained much more cholesterol and less protein than did Golgi membranes. We conclude that two distinct lipoprotein-filled organelles are located in the bile canalicular pole of hepatocytes. MVBs, a major prelysosomal organelle of low density in the endocytic pathway, contain remnants of triglyceride-rich lipoproteins, whereas secretory vesicles of the Golgi apparatus contain nascent very low density lipoproteins. PMID:3988801

Integrated biostratigraphy of foraminifers, radiolarians and conodonts in shallow and deep water Middle Permian (Capitanian) deposits of the "Rader slide", Guadalupe Mountains, West Texas

USGS Publications Warehouse

Nestell, M.K.; Nestell, G.P.; Wardlaw, B.R.; Sweatt, M.J.

2006-01-01

A diverse assemblage of microfossils is present in a 6m thick sequence of three debris flow deposits interbedded with thin turbidite limestone beds and fine grained siliciclastics exposed above the megaconglomerate in a section (known as the "Rader Slide" in numerous guidebook stops) of the Rader Limestone Member of the Bell Canyon Formation of Capitanian age (Middle Permian) in the Guadalupe Mountains of West Texas. Each debris flow, derived from nearby Capitan Reef shelf-margin and slope deposits, contains a distinct microfossil assemblage. Small foraminifers and fusulinaceans, conodonts, radiolarians, sponge spicules, fish dermal plates and teeth, and other fragmental fossils are present in this sequence. Conodonts are relatively scarce in the first (or lowest) debris flow, except in its upper part, but they are common to abundant in the other two debris flows, and very abundant in several of the thin turbidite limestone beds. All of the conodonts present appear to be morphotypes of one population of the species Jinogondolella postserrata, except for one new conodont species, and the Jinogondolella postserrata Zone is clearly documented in this sequence. The debris flows contain the fusulinaceans Rauserella, rare Codonofusiella, Polydiexodina, Leella? and various species of the small foraminifers Globivalvulina, Hemigordius, Baisalina, Abadehella, Deckerella, Neoendothyranella, Vachardella, Geinitzina, and Polarisella. Some of the thin turbidite limestone beds contain a foraminiferal assemblage similar to that found in the debris flows, but with lower diversity. Many small foraminiferal species appear to be endemic, although a few are closely related to species known in Permian age strata in Italy, Greenland, the Russian Far East, northeastern part of Russia (Omolon massif), and the Zechstein of Germany and the Baltic area. Two thin limestone beds above the second debris flow contain primarily radiolarian species known from the Follicucullus japonicus Zone of Japan. Nine new species of small foraminifers (Bisphaera? improvisa, Vissariotaxis? nativus, Multidiscus raderensis, Baisalina miscella, Agathammina minuscula, Polarisella globosa, Geinitzina jucunda, Robustopachyphloia texana and Spireitlina capitanensis) and one new conodont species Jinogondolella gladirobusta are described.

7 CFR 201.42 - Small containers.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Small containers. 201.42 Section 201.42 Agriculture... REGULATIONS Sampling in the Administration of the Act § 201.42 Small containers. In sampling seed in small containers that it is not practical to sample as required in § 201.41, a portion of one unopened container or...

7 CFR 51.1216 - Size requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Standards for Grades of Peaches Size § 51.1216 Size requirements. (a) The numerical count or a count-size... closed container shall be indicated on the container. (b) When the numerical count is not shown the...

7 CFR 51.1216 - Size requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Standards for Grades of Peaches Size § 51.1216 Size requirements. (a) The numerical count or a count-size... closed container shall be indicated on the container. (b) When the numerical count is not shown the...

7 CFR 51.1216 - Size requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Standards for Grades of Peaches Size § 51.1216 Size requirements. (a) The numerical count or a count-size... closed container shall be indicated on the container. (b) When the numerical count is not shown the...

The effect of travel speed on thermal response in CO2 laser welding of small electronic components

NASA Astrophysics Data System (ADS)

Gianoulakis, S. E.; Burchett, S. N.; Fuerschbach, P. W.; Knorovsky, G. A.

A comprehensive three-dimensional numerical investigation of the effect of beat source travel speed on temperatures and resulting thermal stresses was performed for CO2-laser welding. The test specimen was a small thermal battery header containing several stress-sensitive glass-to-metal seals surrounding the electrical connections and a temperature sensitive ignitor located under the header near the center. Predictions of the thermal stresses and temperatures in the battery header were made for several travel speeds of the laser. The travel speeds examined ranged from 10mm/sec to 50mm/sec. The results indicate that faster weld speeds result in lower temperatures and stresses for the same size weld. This is because the higher speed welds are more efficient, requiring less energy to produce a given weld. Less energy absorbed by the workpiece results in lower temperatures, which results in lower stresses.

Asteroids Search Results in Large Photographic Sky Surveys

NASA Astrophysics Data System (ADS)

Shatokhina, S. V.; Kazantseva, L. V.; Yizhakevych, O. M.; Eglitis, I.; Andruk, V. M.

Photographic observations of XX century contained numerous and varied information about all objects and events of the Universe fixed on plates. The original and interesting observations of small bodies of the Solar system in previous years can be selected and used for various scientific tasks. Existing databases and online services can help make such selection easily and quickly. The observations of chronologically earlier ppositions, photometric evaluation of brightness for long periods of time allow refining the orbits of asteroids and identifying various non-stationaries. Photographic observations of Northern Sky Survey project and observations of clusters in UBVR bands were used for global search for small bodies of Solar system. Total we founded 2486 positions of asteroids and 13 positions of comets. All positions were compared with ephemeris. It was found that 80 positions of asteroids have a moment of observation preceding their discovery, and 19 of them are chronologically the earliest observations of these asteroids in the world.

Language, procedures, and the non-perceptual origin of number word meanings.

PubMed

Barner, David

2017-05-01

Perceptual representations of objects and approximate magnitudes are often invoked as building blocks that children combine to acquire the positive integers. Systems of numerical perception are either assumed to contain the logical foundations of arithmetic innately, or to supply the basis for their induction. I propose an alternative to this framework, and argue that the integers are not learned from perceptual systems, but arise to explain perception. Using cross-linguistic and developmental data, I show that small (~1-4) and large (~5+) numbers arise both historically and in individual children via distinct mechanisms, constituting independent learning problems, neither of which begins with perceptual building blocks. Children first learn small numbers using the same logic that supports other linguistic number marking (e.g. singular/plural). Years later, they infer the logic of counting from the relations between large number words and their roles in blind counting procedures, only incidentally associating number words with approximate magnitudes.

Greenland as seen by the STS-66 shuttle Atlantis

NASA Technical Reports Server (NTRS)

1994-01-01

This north-looking view of southwestern Greenland was taken in November, 1994, and shows numerous indentations, many of which contain small settlements. These fjords were carved by the glaciers of the last ice age 10,000 years ago. Even today, the ice in the center of Greenland is nearly 3,500 meters (11,000 feet) thick and great rivers of ice continuously flow down toward the sea, where they melt or break off as icebergs. Some Icebergs exceed the size of small islands, weigh several million tons, and rise several hundred feet above the sea surface. Cape Farewell is visible toward the bottom right of the view. Julianehab Bay and the Bredev fjord can be seen toward the center of the photograph. Godthab, the main settlement on Greenland, is barely visible to the north of the Frederikeshabs Icefield near the left center of the view.

Greenland as seen by the STS-66 shuttle Atlantis

NASA Image and Video Library

1994-11-14

This north-looking view of southwestern Greenland was taken in November, 1994, and shows numerous indentations, many of which contain small settlements. These fjords were carved by the glaciers of the last ice age 10,000 years ago. Even today, the ice in the center of Greenland is nearly 3,500 meters (11,000 feet) thick and great rivers of ice continuously flow down toward the sea, where they melt or break off as icebergs. Some Icebergs exceed the size of small islands, weigh several million tons, and rise several hundred feet above the sea surface. Cape Farewell is visible toward the bottom right of the view. Julianehab Bay and the Bredev fjord can be seen toward the center of the photograph. Godthab, the main settlement on Greenland, is barely visible to the north of the Frederikeshabs Icefield near the left center of the view.

Effects of surface poisons on the oxidation of binary alloys

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

Hagan, P.S.; Polizzotti, R.S.; Luckman, G.

1985-10-01

A system of reaction-diffusion equations describing the oxidation of binary alloys in environments containing small amounts of surface poisons is analyzed. These poisons reduce the oxygen flux into the alloy, which causes the alloy to oxidize in two stages.During the initial stage, the oxidation reaction occurs in a stationary boundary layer at the alloy surface. Consequently, a thin zone containing a very high concentration of the metal oxide is created at the alloy surface. During the second stage, the oxidation reaction occurs in a moving boundary layer. This leads to a Stefan problem, which is analyzed by using asymptotic andmore » numerical techniques. By comparing the solutions to those of alloys in unpoisoned environments, it is concluded that surface poisons can lead to the formation of protective external oxide scales in alloys which would not normally form such scales. 11 references.« less

Efficiency of Cathodoluminescence Emission by Nitrogen-Vacancy Color Centers in Nanodiamonds.

PubMed

Zhang, Huiliang; Glenn, David R; Schalek, Richard; Lichtman, Jeff W; Walsworth, Ronald L

2017-06-01

Correlated electron microscopy and cathodoluminescence (CL) imaging using functionalized nanoparticles is a promising nanoscale probe of biological structure and function. Nanodiamonds (NDs) that contain CL-emitting color centers are particularly well suited for such applications. The intensity of CL emission from NDs is determined by a combination of factors, including particle size, density of color centers, efficiency of energy deposition by electrons passing through the particle, and conversion efficiency from deposited energy to CL emission. This paper reports experiments and numerical simulations that investigate the relative importance of each of these factors in determining CL emission intensity from NDs containing nitrogen-vacancy (NV) color centers. In particular, it is found that CL can be detected from NV-doped NDs with dimensions as small as ≈40 nm, although CL emission decreases significantly for smaller NDs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Post-irradiation-examination of irradiated fuel outside the hot cell

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

Dawn E. Janney; Adam B. Robinson; Thomas P. O'Holleran

Because of their high radioactivity, irradiated fuels are commonly examined in a hot cell. However, the Idaho National Laboratory (INL) has recently investigated irradiated U-Mo-Al metallic fuel from the Reduced Enrichment for Research and Test Reactors (RERTR) project using a conventional unshielded scanning electron microscope outside a hot cell. This examination was possible because of a two-step sample-preparation approach in which a small volume of fuel was isolated in a hot cell and shielding was introduced during later stages of sample preparation. The resulting sample contained numerous sample-preparation artifacts but allowed analysis of microstructures from selected areas.

The Coffee Sand and Ripley aquifers in Mississippi

USGS Publications Warehouse

Boswell, E.H.

1978-01-01

The Coffee Sand and Ripley aquifers, of Cretaceous age, are in the Selma Group in northern Mississippi. The aquifers contain freshwater in an area of about 4,400 square miles in northern Mississippi. Water produced from the aquifers by public water systems and numerous industries in 1975 averaged about 4 Mgal/d. Regional water-level declines have been very small and the aquifers have a moderate potential for future development. The aquifers are used in some areas where there are no other significant sources of ground water. The most common problems in developing water supplies are low yields to wells and hard water. (Kosco-USGS)

THE CELLULAR ORIGIN OF HUMAN IMMUNOGLOBULINS (γ2, γ1M, γ1A)

PubMed Central

Mellors, Robert C.; Korngold, Leonhard

1963-01-01

A study was made of the cellular origin of human immunoglobulins (γ2, γ1M, γ1A). The results indicated that two closely related families of cells form immunoglobulins in human lymphoid tissue: germinal (reticular) centers and plasma cells. Thus their cellular origin in addition to their known antigenic relations further justifies placing the immunoglobulins in one family of proteins. Immunoglobulins were also formed to a small extent in primitive reticular cells which resembled those of germinal centers but were separated from them. Possibly such cells were undergoing transition to the much more numerous plasma cells with which they were commonly associated. The mantles of small lymphocytes which surrounded germinal centers did not contain detectable quantities of immunoglobulins. While in general only one type of immunoglobulin was present in an individual cell or germinal center, γ2- and γ1M-globulin were identified on occasion in the same plasma cell and germinal center. A peculiarity of the fetal thymus gland was the presence of immunoglobulin, mainly γ1M, in a small number of cells of small and intermediate size and primitive reticular appearance and in Hassall's corpuscles. PMID:14077999

Numerical simulation of the compressible Orszag-Tang vortex. Interim report, June 1988-February 1989

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

Dahlburg, R.B.; Picone, J.M.

Results of fully compressible, Fourier collocation, numerical simulations of the Orszag-Tang vortex system are presented. Initial conditions consist of a nonrandom, periodic field in which the magnetic and velocity fields contain X-points but differ in modal structure along one spatial direction. The velocity field is initially solenoidal, with the total initial pressure-field consisting of the superposition of the appropriate incompressible pressure distribution upon a flat pressure field corresponding to the initial, average flow Mach number of the flow. In the numerical simulations, this initial Mach number is varied from 0.2 to 0.6. These values correspond to average plasma beta valuesmore » ranging from 30.0 to 3.3, respectively. Compressible effects develop within one or two Alfven transit times, as manifested in the spectra of compressible quantities such as mass density and nonsolenoidal flow field. These effects include (1) retardation of growth of correlation between the magnetic field and the velocity field, (2) emergence of compressible small-scale structure such as massive jets, and (3) bifurcation of eddies in the compressible-flow field. Differences between the incompressible and compressible results tend to increase with increasing initial average Mach number.« less

Determination of sedimentation coefficients for small peptides.

PubMed Central

Schuck, P; MacPhee, C E; Howlett, G J

1998-01-01

Direct fitting of sedimentation velocity data with numerical solutions of the Lamm equations has been exploited to obtain sedimentation coefficients for single solutes under conditions where solvent and solution plateaus are either not available or are transient. The calculated evolution was initialized with the first experimental scan and nonlinear regression was employed to obtain best-fit values for the sedimentation and diffusion coefficients. General properties of the Lamm equations as data analysis tools were examined. This method was applied to study a set of small peptides containing amphipathic heptad repeats with the general structure Ac-YS-(AKEAAKE)nGAR-NH2, n = 2, 3, or 4. Sedimentation velocity analysis indicated single sedimenting species with sedimentation coefficients (s(20,w) values) of 0.37, 0.45, and 0.52 S, respectively, in good agreement with sedimentation coefficients predicted by hydrodynamic theory. The described approach can be applied to synthetic boundary and conventional loading experiments, and can be extended to analyze sedimentation data for both large and small macromolecules in order to define shape, heterogeneity, and state of association. PMID:9449347

Wind noise spectra in small Reynolds number turbulent flows.

PubMed

Zhao, Sipei; Cheng, Eva; Qiu, Xiaojun; Burnett, Ian; Liu, Jacob Chia-Chun

2017-11-01

Wind noise spectra caused by wind from fans in indoor environments have been found to be different from those measured in outdoor atmospheric conditions. Although many models have been developed to predict outdoor wind noise spectra under the assumption of large Reynolds number [Zhao, Cheng, Qiu, Burnett, and Liu (2016). J. Acoust. Soc. Am. 140, 4178-4182, and the references therein], they cannot be applied directly to the indoor situations because the Reynolds number of wind from fans in indoor environments is usually much smaller than that experienced in atmospheric turbulence. This paper proposes a pressure structure function model that combines the energy-containing and dissipation ranges so that the pressure spectrum for small Reynolds number turbulent flows can be calculated. The proposed pressure structure function model is validated with the experimental results in the literature, and then the obtained pressure spectrum is verified with the numerical simulation and experiment results. It is demonstrated that the pressure spectrum obtained from the proposed pressure structure function model can be utilized to estimate wind noise spectra caused by turbulent flows with small Reynolds numbers.

Digestion modeling in the small intestine: impact of dietary fiber.

PubMed

Taghipoor, M; Barles, G; Georgelin, C; Licois, J R; Lescoat, P

2014-12-01

In this work, the modeling of the digestion in the small intestine is developed by investigating specifically the effects of dietary fiber. As our previous model, this new version takes into account the three main phenomena of digestion: transit of the bolus, degradation of feedstuffs and absorption through the intestinal wall. However the two main physiochemical characteristics of dietary fiber, namely viscosity and water holding capacity, lead us to substantially modify our initial model by emphasizing the role of water and its intricated dynamics with dry matter in the bolus. Various numerical simulations given by this new model are qualitatively in agreement with the positive effect of insoluble dietary fiber on the velocity of bolus and on its degradation all along the small intestine. These simulations reproduce the negative effect of soluble dietary fiber on digestion as it has been experimentally observed. Although, this model is generic and contains a large number of parameters but, to the best of our knowledge, it is among the first qualitative dynamical models of fiber influence on intestinal digestion. Copyright © 2014 Elsevier Inc. All rights reserved.

SM-TF: A structural database of small molecule-transcription factor complexes.

PubMed

Xu, Xianjin; Ma, Zhiwei; Sun, Hongmin; Zou, Xiaoqin

2016-06-30

Transcription factors (TFs) are the proteins involved in the transcription process, ensuring the correct expression of specific genes. Numerous diseases arise from the dysfunction of specific TFs. In fact, over 30 TFs have been identified as therapeutic targets of about 9% of the approved drugs. In this study, we created a structural database of small molecule-transcription factor (SM-TF) complexes, available online at http://zoulab.dalton.missouri.edu/SM-TF. The 3D structures of the co-bound small molecule and the corresponding binding sites on TFs are provided in the database, serving as a valuable resource to assist structure-based drug design related to TFs. Currently, the SM-TF database contains 934 entries covering 176 TFs from a variety of species. The database is further classified into several subsets by species and organisms. The entries in the SM-TF database are linked to the UniProt database and other sequence-based TF databases. Furthermore, the druggable TFs from human and the corresponding approved drugs are linked to the DrugBank. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Physician Practice Consolidation Driven By Small Acquisitions, So Antitrust Agencies Have Few Tools To Intervene.

PubMed

Capps, Cory; Dranove, David; Ody, Christopher

2017-09-01

The growing concentration of physician markets throughout the United States has been raising antitrust concerns, yet the Department of Justice and the Federal Trade Commission have challenged only a small number of mergers and acquisitions in this field. Using proprietary claims data from states collectively containing more than 12 percent of the US population, we found that 22 percent of physician markets were highly concentrated in 2013, according to federal merger guidelines. Most of the increases in physician practice size and market concentration resulted from numerous small transactions, rather than a few large transactions. Among highly concentrated markets that had increases large enough to raise antitrust concerns, only 28 percent experienced any individual acquisition that would have been presumed to be anticompetitive under federal merger guidelines. Furthermore, most acquisitions were below the dollar thresholds that would have required the parties to report the transaction to antitrust authorities. Under present mechanisms, federal authorities have only limited ability to counteract consolidation in most US physician markets. Project HOPE—The People-to-People Health Foundation, Inc.

Electron microscopy of vesicular-arbuscular mycorrhizae of yellow poplar. III Host-endophyte interactions during arbuscular development.

PubMed

Kinden, D A; Brown, M F

1975-12-01

Scanning- and transmission-electron microscopy were used to examine developing and mature functional arbuscules in mycorrhizal roots of yellow poplar. Arbuscules developed from intracellular hyphae which branched repeatedly upon penetration into the host cells. Intermediate and late stages of developemnt were characterized by the production of numerous, short, bifurcate hyphae throughout the arbuscule. Mature arbuscules exhibited a coralloid morphology which resulted in a considerable increase in the surface area of the endophyte exposed within the host cells. Distinctive ultrastructural features of arbuscular hyphae included osmiophilic walls, nuclei, abundant cytoplasm, glycogen, and numerous small vacuoles. All arbuscular components were enclosed by host wall material and cytoplasm during development and at maturity. In infected cells, host nuclei were enlarged and the cytoplasm associated with the arbuscular branches typically contained abundant mitochondria, endoplasmic reticulum, and proplastids. Ultrastructural observations suggested that nutrient transfer may be predominantly directed toward the fungal endophyte during arbuscular development and while mature arbuscules remain functional.

[Mysteries of a medicine chest ].

PubMed

Lefrère, Bertrand

2017-03-01

This article retraces the history of an old medicine chest, used at the beginning of the 19th century, but probably designed earlier. Possibly made in A ustria, with a two-headed eagle lining the bottom of the lid, this first-aid kit belongs to a small group of related chests. It should be noted that these chests were used for a wide variety of different purposes over time. Also named a «droguier» in French, this light chest, made of walnut, and, according to family lore, found in Normandy, would have belonged to a doctor, as confirmed by a short invoice found among numerous documents. The identity of the supplier of numerous old medicines is shown on the labels on the flasks (many of which are intact) and other boxes (containing, in particular, herbal drugs) : «Clément, Apothicaire. Rue St Onge N°. 42. près le Bd. du Temple A Paris», whose history is recounted here step by step.

Reducing mechanical cross-coupling in phased array transducers using stop band material as backing

NASA Astrophysics Data System (ADS)

Henneberg, J.; Gerlach, A.; Storck, H.; Cebulla, H.; Marburg, S.

2018-06-01

Phased array transducers are widely used for acoustic imaging and surround sensing applications. A major design challenge is the achievement of low mechanical cross-coupling between the single transducer elements. Cross-coupling induces a loss of imaging resolution. In this work, the mechanical cross-coupling between acoustic transducers is investigated for a generic model. The model contains a common backing with two bending elements bonded on top. The dimensions of the backing are small; thus, wave reflections on the backing edges have to be considered. This is different to other researches. The operating frequency in the generic model is set to a low kHz range. Low operating frequencies are typical for surround sensing applications. The influence of the backing on cross-coupling is investigated numerically. In order to reduce mechanical cross-coupling a stop band material is designed. It is shown numerically that a reduction in mechanical cross-coupling can be achieved by using stop band material as backing. The effect is validated with experimental testing.

Infectious mononucleosis lymphoadenitis showing histologic findings indistinguishable from toxoplasma lymphadenitis. A report of three cases.

PubMed

Kojima, Masaru; Kashimura, Makoto; Itoh, Hideaki; Noro, Masahiro; Matsuda, Hazuki; Tsukamoto, Norihumi; Akikusa, Bunshiro; Masawa, Nobuhide; Morita, Yukio

2010-06-15

Lymph node lesions in infectious mononucleosis (IM) show a marked histologic diversity. We report here three cases of IM lymphadenitis with histologic findings indistinguishable from those of toxoplasmic lymphadenitis. The histologic findings of the three cases presented here showed a histologic triad of toxoplasmic lymphadenitis, including (i) numerous lymphoid follicles with hyperplastic germinal centers; (ii) small clusters or single epithelioid histiocytes; and (iii) multiple foci of monocytoid B-cells. Moreover, all three lesions contained isolated or small clusters of epithelioid histiocytes within the hyperplastic germinal centers and the periphery of lymphoid follicles, which are the most specific histologic findings of toxoplasmic lymphadenitis. However, serologic findings confirmed EBV infection in all three cases. On in situ hybridization, numerous Epstein-Barr virus (EBV)-encoded small RNA (EBER)-positive cells were demonstrated in the germinal center, as well as in interfollicular areas in all three cases. Toxoplasmosis gondii infection was excluded in at least one case, based on serologic findings. Polymerase chain reaction analysis also demonstrated that there was no T. gondii DNA in the remaining two cases. Two of our three cases showed atypical clinical presentations, including an absence of atypical lymphocytosis in peripheral blood in two cases, age more than 30 years, and an absence of systemic symptoms in one case. It appears that previous descriptions emphasize the differential diagnostic problems between IM lymphadenitis and malignant lymphomas. However, from a therapeutic perspective, it is important to discriminate IM lymphadenitis from toxoplasmic lymphadenitis particularly in patients showing atypical clinical features. 2010 Elsevier GmbH. All rights reserved.

Small-x asymptotics of the quark helicity distribution: Analytic results

DOE PAGES

Kovchegov, Yuri V.; Pitonyak, Daniel; Sievert, Matthew D.

2017-06-15

In this Letter, we analytically solve the evolution equations for the small-x asymptotic behavior of the (flavor singlet) quark helicity distribution in the large- N c limit. Here, these evolution equations form a set of coupled integro-differential equations, which previously could only be solved numerically. This approximate numerical solution, however, revealed simplifying properties of the small-x asymptotics, which we exploit here to obtain an analytic solution.

The influence of graphic display format on the interpretations of quantitative risk information among adults with lower education and literacy: a randomized experimental study.

PubMed

McCaffery, Kirsten J; Dixon, Ann; Hayen, Andrew; Jansen, Jesse; Smith, Sian; Simpson, Judy M

2012-01-01

To test optimal graphic risk communication formats for presenting small probabilities using graphics with a denominator of 1000 to adults with lower education and literacy. A randomized experimental study, which took place in adult basic education classes in Sydney, Australia. The participants were 120 adults with lower education and literacy. An experimental computer-based manipulation compared 1) pictographs in 2 forms, shaded "blocks" and unshaded "dots"; and 2) bar charts across different orientations (horizontal/vertical) and numerator size (small <100, medium 100-499, large 500-999). Accuracy (size of error) and ease of processing (reaction time) were assessed on a gist task (estimating the larger chance of survival) and a verbatim task (estimating the size of difference). Preferences for different graph types were also assessed. Accuracy on the gist task was very high across all conditions (>95%) and not tested further. For the verbatim task, optimal graph type depended on the numerator size. For small numerators, pictographs resulted in fewer errors than bar charts (blocks: odds ratio [OR] = 0.047, 95% confidence interval [CI] = 0.023-0.098; dots: OR = 0.049, 95% CI = 0.024-0.099). For medium and large numerators, bar charts were more accurate (e.g., medium dots: OR = 4.29, 95% CI = 2.9-6.35). Pictographs were generally processed faster for small numerators (e.g., blocks: 14.9 seconds v. bars: 16.2 seconds) and bar charts for medium or large numerators (e.g., large blocks: 41.6 seconds v. 26.7 seconds). Vertical formats were processed slightly faster than horizontal graphs with no difference in accuracy. Most participants preferred bar charts (64%); however, there was no relationship with performance. For adults with low education and literacy, pictographs are likely to be the best format to use when displaying small numerators (<100/1000) and bar charts for larger numerators (>100/1000).

Detection Of Special Nuclear Materials Tagged Neutrons

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

Deyglun, Clement; Perot, Bertrand; Carasco, Cedric

In order to detect Special Nuclear Materials (SNM) in unattended luggage or cargo containers in the field of homeland security, fissions are induced by 14 MeV neutrons produced by an associated particle DT neutron generator, and prompt fission particles correlated with tagged neutron are detected by plastic scintillators. SMN produce high multiplicity events due to induced fissions, whereas nonnuclear materials produce low multiplicity events due to cross-talk, (n,2n) or (n,n'γ) reactions. The data acquisition electronics is made of compact FPGA boards. The coincidence window is triggered by the alpha particle detection, allowing to tag the emission date and direction ofmore » the 14 MeV interrogating neutron. The first part of the paper presents experiment vs. calculation comparisons to validate MCNP-PoliMi simulations and the post-processing tools developed with the data analysis framework ROOT. Measurements have been performed using different targets (iron, lead, graphite), first with small plastic scintillators (10 x 10 x 10 cm{sup 3}) and then with large detectors (10 x 10 x 100 cm{sup 3}) to demonstrate that nuclear materials can be differentiated from nonnuclear dense materials (iron, lead) in iron and wood matrixes. A special attention is paid on SNM detection in abandoned luggage. In the second part of the paper, the performances of a cargo container inspection system are studied by numerical simulation, following previous work reported in. Detectors dimensions and shielding against the neutron generator background are optimized for container inspection. Events not correlated to an alpha particle (uncorrelated background), counting statistics, time and energy resolutions of the data acquisition system are all taken into account in a realistic numerical model. The impact of the container matrix (iron, ceramic, wood) has been investigated by studying the system capability to detect a few kilograms of SNM in different positions in the cargo container, within 10 min acquisitions. (authors)« less

3D reconstruction of carbon nanotube networks from neutron scattering experiments

DOE PAGES

Mahdavi, Mostafa; Baniassadi, Majid; Baghani, Mostafa; ...

2015-09-03

Structure reconstruction from statistical descriptors, such as scattering data obtained using x-rays or neutrons, is essential in understanding various properties of nanocomposites. Scattering based reconstruction can provide a realistic model, over various length scales, that can be used for numerical simulations. In this study, 3D reconstruction of a highly loaded carbon nanotube (CNT)-conducting polymer system based on small and ultra-small angle neutron scattering (SANS and USANS, respectively) data was performed. These light-weight and flexible materials have recently shown great promise for high-performance thermoelectric energy conversion, and their further improvement requires a thorough understanding of their structure-property relationships. The first stepmore » in achieving such understanding is to generate models that contain the hierarchy of CNT networks over nano and micron scales. The studied system is a single walled carbon nanotube (SWCNT)/poly (3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS). SANS and USANS patterns of the different samples containing 10, 30, and 50 wt% SWCNTs were measured. These curves were then utilized to calculate statistical two-point correlation functions of the nanostructure. These functions along with the geometrical information extracted from SANS data and scanning electron microscopy images were used to reconstruct a representative volume element (RVE) nanostructure. Generated RVEs can be used for simulations of various mechanical and physical properties. This work, therefore, introduces a framework for the reconstruction of 3D RVEs of high volume faction nanocomposites containing high aspect ratio fillers from scattering experiments.« less

3D reconstruction of carbon nanotube networks from neutron scattering experiments

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

Mahdavi, Mostafa; Baniassadi, Majid; Baghani, Mostafa

Structure reconstruction from statistical descriptors, such as scattering data obtained using x-rays or neutrons, is essential in understanding various properties of nanocomposites. Scattering based reconstruction can provide a realistic model, over various length scales, that can be used for numerical simulations. In this study, 3D reconstruction of a highly loaded carbon nanotube (CNT)-conducting polymer system based on small and ultra-small angle neutron scattering (SANS and USANS, respectively) data was performed. These light-weight and flexible materials have recently shown great promise for high-performance thermoelectric energy conversion, and their further improvement requires a thorough understanding of their structure-property relationships. The first stepmore » in achieving such understanding is to generate models that contain the hierarchy of CNT networks over nano and micron scales. The studied system is a single walled carbon nanotube (SWCNT)/poly (3,4-ethylenedioxythiophene): poly (styrene sulfonate) (PEDOT: PSS). SANS and USANS patterns of the different samples containing 10, 30, and 50 wt% SWCNTs were measured. These curves were then utilized to calculate statistical two-point correlation functions of the nanostructure. These functions along with the geometrical information extracted from SANS data and scanning electron microscopy images were used to reconstruct a representative volume element (RVE) nanostructure. Generated RVEs can be used for simulations of various mechanical and physical properties. This work, therefore, introduces a framework for the reconstruction of 3D RVEs of high volume faction nanocomposites containing high aspect ratio fillers from scattering experiments.« less

Geotechnical studies relevant to the containment of underground nuclear explosions at the Nevada Test Site

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

Heuze, F.E.

1982-05-01

The Department of Energy and the Department of Defense are actively pursuing a program of nuclear weapons testing by underground explosions at the Nevada Test Site (NTS). Over the past 11 years, scores of tests have been conducted and the safety record is very good. In the short run, emphasis is put on preventing the release of radioactive materials into the atmosphere. In the long run, the subsidence and collapse of the ground above the nuclear cavities also are matters of interest. Currently, estimation of containment is based mostly on empiricism derived from extensive experience and on a combination ofmore » physical/mechanical testing and numerical modeling. When measured directly, the mechanical material properties are obtained from short-term laboratory tests on small, conventional samples. This practice does not determine the large effects of scale and time on measured stiffnesses and strengths of geological materials. Because of the limited data base of properties and in situ conditions, the input to otherwise fairly sophisticated computer programs is subject to several simplifying assumptions; some of them can have a nonconservative impact on the calculated results. As for the long-term, subsidence and collapse phenomena simply have not been studied to any significant degree. This report examines the geomechanical aspects of procedures currently used to estimate containment of undergroung explosions at NTS. Based on this examination, it is concluded that state-of-the-art geological engineering practice in the areas of field testing, large scale laboratory measurements, and numerical modeling can be drawn upon to complement the current approach.« less

Observation Platform for Dynamic Biomedical and Biotechnology Experiments Using the International Space Station (ISS) Light Microscopy Module (LMM)

NASA Technical Reports Server (NTRS)

Kurk, Michael A. (Andy)

2015-01-01

Techshot, Inc., has developed an observation platform for the LMM on the ISS that will enable biomedical and biotechnology experiments. The LMM Dynamic Stage consists of an electronics module and the first two of a planned suite of experiment modules. Specimens and reagent solutions can be injected into a small, hollow microscope slide-the heart of the innovation-via a combination of small reservoirs, pumps, and valves. A life science experiment module allows investigators to load up to two different fluids for on-orbit, real-time image cytometry. Fluids can be changed to initiate a process, fix biological samples, or retrieve suspended cells. A colloid science experiment module conducts microparticle and nanoparticle tests for investigation of colloid self-assembly phenomena. This module includes a hollow glass slide and heating elements for the creation of a thermal gradient from one end of the slide to the other. The electronics module supports both experiment modules and contains a unique illuminator/condenser for bright and dark field and phase contrast illumination, power supplies for two piezoelectric pumps, and controller boards for pumps and valves. This observation platform safely contains internal fluids and will greatly accelerate the research and development (R&D) cycle of numerous experiments, products, and services aboard the ISS.

Trojan resonant dynamics, stability, and chaotic diffusion, for parameters relevant to exoplanetary systems

NASA Astrophysics Data System (ADS)

Páez, Rocío Isabel; Efthymiopoulos, Christos

2015-02-01

The possibility that giant extrasolar planets could have small Trojan co-orbital companions has been examined in the literature from both viewpoints of the origin and dynamical stability of such a configuration. Here we aim to investigate the dynamics of hypothetical small Trojan exoplanets in domains of secondary resonances embedded within the tadpole domain of motion. To this end, we consider the limit of a massless Trojan companion of a giant planet. Without other planets, this is a case of the elliptic restricted three body problem (ERTBP). The presence of additional planets (hereafter referred to as the restricted multi-planet problem, RMPP) induces new direct and indirect secular effects on the dynamics of the Trojan body. The paper contains a theoretical and a numerical part. In the theoretical part, we develop a Hamiltonian formalism in action-angle variables, which allows us to treat in a unified way resonant dynamics and secular effects on the Trojan body in both the ERTBP or the RMPP. In both cases, our formalism leads to a decomposition of the Hamiltonian in two parts, . , called the basic model, describes resonant dynamics in the short-period (epicyclic) and synodic (libration) degrees of freedom, while contains only terms depending trigonometrically on slow (secular) angles. is formally identical in the ERTBP and the RMPP, apart from a re-definition of some angular variables. An important physical consequence of this analysis is that the slow chaotic diffusion along resonances proceeds in both the ERTBP and the RMPP by a qualitatively similar dynamical mechanism. We found that this is best approximated by the paradigm of `modulational diffusion'. In the paper's numerical part, we then focus on the ERTBP in order to make a detailed numerical demonstration of the chaotic diffusion process along resonances. Using color stability maps, we first provide a survey of the resonant web for characteristic mass parameter values of the primary, in which the secondary resonances from 1:5 to 1:12 (ratio of the short over the synodic period), as well as their transverse resonant multiplets, appear. We give numerical examples of diffusion of weakly chaotic orbits in the resonant web. We finally make a statistics of the escaping times in the resonant domain, and find power-law tails of the distribution of the escaping times for the slowly diffusing chaotic orbits. Implications of resonant dynamics in the search for Trojan exoplanets are discussed.

Subcellular Lipid Droplets in Vanilla Leaf Epidermis and Avocado Mesocarp Are Coated with Oleosins of Distinct Phylogenic Lineages1[OPEN

PubMed Central

2016-01-01

Subcellular lipid droplets (LDs) in diverse plant cells and species are coated with stabilizing oleosins of at least five phylogenic lineages and perform different functions. We examined two types of inadequately studied LDs for coated oleosins and their characteristics. The epidermis but not mesophyll of leaves of vanilla (Vanilla planifolia) and most other Asparagales species contained solitary and clustered LDs (<0.5 μm), some previously studied by electron microscopy and speculated to be for cuticle formation. In vanilla leaves, transcripts of oleosins of the U lineage were present in both epidermis and mesophyll, but oleosin occurred only in epidermis. Immuno-confocal laser scanning microscopy revealed that the LDs were coated with oleosins. LDs in isolated fractions did not coalesce, and the fractions contained heterogeneous proteins including oleosins and diverse lipids. These findings reflect the in situ structure and possible functions of the LDs. Fruit mesocarp of avocado (Persea americana) and other Lauraceae species possessed large LDs, which likely function in attracting animals for seed dispersal. They contained transcripts of oleosin of a novel M phylogenic lineage. Each avocado mesocarp fatty cell possessed one to several large LDs (5 to 20 μm) and at their periphery, numerous small LDs (<0.5 μm). Immuno-confocal laser scanning microscopy revealed that oleosin was present mostly on the small LDs. LDs in isolated fractions coalesced rapidly, and the fraction contained oleosin and several other proteins and triacylglycerols as the main lipids. These two new types of oleosin-LDs exemplify the evolutionary plasticity of oleosins-LDs in generating novel functions in diverse cell types and species. PMID:27208281

Subcellular Lipid Droplets in Vanilla Leaf Epidermis and Avocado Mesocarp Are Coated with Oleosins of Distinct Phylogenic Lineages.

PubMed

Huang, Ming-Der; Huang, Anthony H C

2016-07-01

Subcellular lipid droplets (LDs) in diverse plant cells and species are coated with stabilizing oleosins of at least five phylogenic lineages and perform different functions. We examined two types of inadequately studied LDs for coated oleosins and their characteristics. The epidermis but not mesophyll of leaves of vanilla (Vanilla planifolia) and most other Asparagales species contained solitary and clustered LDs (<0.5 μm), some previously studied by electron microscopy and speculated to be for cuticle formation. In vanilla leaves, transcripts of oleosins of the U lineage were present in both epidermis and mesophyll, but oleosin occurred only in epidermis. Immuno-confocal laser scanning microscopy revealed that the LDs were coated with oleosins. LDs in isolated fractions did not coalesce, and the fractions contained heterogeneous proteins including oleosins and diverse lipids. These findings reflect the in situ structure and possible functions of the LDs. Fruit mesocarp of avocado (Persea americana) and other Lauraceae species possessed large LDs, which likely function in attracting animals for seed dispersal. They contained transcripts of oleosin of a novel M phylogenic lineage. Each avocado mesocarp fatty cell possessed one to several large LDs (5 to 20 μm) and at their periphery, numerous small LDs (<0.5 μm). Immuno-confocal laser scanning microscopy revealed that oleosin was present mostly on the small LDs. LDs in isolated fractions coalesced rapidly, and the fraction contained oleosin and several other proteins and triacylglycerols as the main lipids. These two new types of oleosin-LDs exemplify the evolutionary plasticity of oleosins-LDs in generating novel functions in diverse cell types and species. © 2016 American Society of Plant Biologists. All Rights Reserved.

A planetary dust ring generated by impact-ejection from the Galilean satellites

NASA Astrophysics Data System (ADS)

Sachse, Manuel

2018-03-01

All outer planets in the Solar System are surrounded by a ring system. Many of these rings are dust rings or they contain at least a high proportion of dust. They are often formed by impacts of micro-meteoroids onto embedded bodies. The ejected material typically consists of micron-sized charged particles, which are susceptible to gravitational and non-gravitational forces. Generally, detailed information on the dynamics and distribution of the dust requires expensive numerical simulations of a large number of particles. Here we develop a relatively simple and fast, semi-analytical model for an impact-generated planetary dust ring governed by the planet's gravity and the relevant perturbation forces for the dynamics of small charged particles. The most important parameter of the model is the dust production rate, which is a linear factor in the calculation of the dust densities. We apply our model to dust ejected from the Galilean satellites using production rates obtained from flybys of the dust sources. The dust densities predicted by our model are in good agreement with numerical simulations and with in situ measurements by the Galileo spacecraft. The lifetimes of large particles are about two orders of magnitude greater than those of small ones, which implies a flattening of the size distribution in circumplanetary space. Information about the distribution of circumplanetary dust is also important for the risk assessment of spacecraft orbits in the respective regions.

Modeling to study the role of catalyst in the formation of graphitic shells during carbon nanofiber growth subjected to reactive plasma

NASA Astrophysics Data System (ADS)

Gupta, Ravi; Gupta, Neha; Sharma, Suresh C.

2018-04-01

An analytical model to study the role of a metal catalyst nanofilm in the nucleation, growth, and resulting structure of carbon nanofibers (CNFs) in low-temperature hydrogen diluted acetylene plasma has been developed. The model incorporates the nanostructuring of thin catalyst films, growth of CNF, restructuring of catalyst nanoparticles during growth, and its repercussion on the resulting structure (alignment of rolled graphene sheets around catalyst nanoparticles) by taking into account the plasma sheath formalization, kinetics of neutrals and positively charged species in the reactive plasma, flux of plasma species onto the catalyst front surface, and numerous surface reactions for carbon generation. In order to examine the influence of the catalyst film on the growth of CNFs, the numerical solutions of the model equations have been obtained for experimentally determined initial conditions and glow discharge plasma parameters. From the solutions obtained, we found that nanostructuring of thin films leads to the formation of small nanoparticles with high surface number density. The CNF nucleates over these small-sized nanoparticles grow faster and attain early saturation because of the quick poisoning of small-sized catalyst particles, and contain only a few graphitic shells. However, thick nanofilms result in shorter CNFs with large diameters composed of many graphitic shells. Moreover, we found that the inclination of graphitic shells also depends on the extent up to which the catalyst can reconstruct itself during the growth. The small nanoparticles show much greater elongation along the growth axis and also show a very small difference between their tip and base diameter during the growth due to which graphitic shells align at very small angles as compared to the larger nanoparticles. The present study is useful to synthesize the thin and more extended CNFs/CNTs having a smaller opening angle (inclination angle of graphene layers) as the opening angle has a significant influence on their field emission properties. The comparisons of these theoretical findings to the experimental observations confirm the adequacy of the proposed model.

Single-beam, dark toroidal optical traps for cold atoms

NASA Astrophysics Data System (ADS)

Fatemi, Fredrik K.; Olson, Spencer E.; Bashkansky, Mark; Dutton, Zachary; Terraciano, Matthew

2007-02-01

We demonstrate the generation of single-beam dark toroidal optical intensity distributions, which are of interest for neutral atom storage and atom interferometry. We demonstrate experimentally and numerically optical potentials that contain a ring-shaped intensity minimum, bounded in all directions by higher intensity. We use a spatial light modulator to alter the phase of an incident laser beam, and analyze the resulting optical propagation characteristics. For small toroidal traps (< 50 μm diameter), we find an optimal superposition of Laguerre-Gaussian modes that allows the formation of single-beam toroidal traps. We generate larger toroidal bottle traps by focusing hollow beams with toroidal lenses imprinted onto the spatial light modulator.

A new adaptive estimation method of spacecraft thermal mathematical model with an ensemble Kalman filter

NASA Astrophysics Data System (ADS)

Akita, T.; Takaki, R.; Shima, E.

2012-04-01

An adaptive estimation method of spacecraft thermal mathematical model is presented. The method is based on the ensemble Kalman filter, which can effectively handle the nonlinearities contained in the thermal model. The state space equations of the thermal mathematical model is derived, where both temperature and uncertain thermal characteristic parameters are considered as the state variables. In the method, the thermal characteristic parameters are automatically estimated as the outputs of the filtered state variables, whereas, in the usual thermal model correlation, they are manually identified by experienced engineers using trial-and-error approach. A numerical experiment of a simple small satellite is provided to verify the effectiveness of the presented method.

An immunoelectron microscopic study of methionine-enkephalin structures in cat prevertebral ganglia.

PubMed

Benfares, J; Henry, M; Cupo, A; Julé, Y

1995-03-01

Methionine-enkephalin-like immunoreactivity was detected in presynaptic nerve fibers and SIF cells in cat prevertebral ganglia. The immunoreactive nerve fibers contained a mixture of numerous small clear vesicles and a few large vesicles; the immunoreactivity was only confined to the large vesicles. Most of the immunoreactive fibers were in apposition with non-immunoreactive neuronal profiles, without any detectable synaptic membrane specializations. The other immunoreactive fibers formed synaptic contacts mainly with non-immunostained dendrites and to a lesser extent with axons and neuronal soma. The characterization at the ultrastructural level of the enkephalin-like immunoreactive structures is discussed as regards the modalities whereby opiates may be involved in sympathetic ganglionic transmission.

A numerical and experimental study of three-dimensional liquid sloshing in a rotating spherical container

NASA Technical Reports Server (NTRS)

Chen, Kuo-Huey; Kelecy, Franklyn J.; Pletcher, Richard H.

1992-01-01

A numerical and experimental study of three dimensional liquid sloshing inside a partially-filled spherical container undergoing an orbital rotating motion is described. Solutions of the unsteady, three-dimensional Navier-Stokes equations for the case of a gradual spin-up from rest are compared with experimental data obtained using a rotating test rig fitted with two liquid-filled spherical tanks. Data gathered from several experiments are reduced in terms of a dimensionless free surface height for comparison with transient results from the numerical simulations. The numerical solutions are found to compare favorably with the experimental data.

Numerical Simulation of the Freeze-Thaw Behavior of Mortar Containing Deicing Salt Solution

PubMed Central

Esmaeeli, Hadi S.; Farnam, Yaghoob; Bentz, Dale P.; Zavattieri, Pablo D.; Weiss, Jason

2016-01-01

This paper presents a one-dimensional finite difference model that is developed to describe the freeze-thaw behavior of an air-entrained mortar containing deicing salt solution. A phenomenological model is used to predict the temperature and the heat flow for mortar specimens during cooling and heating. Phase transformations associated with the freezing/melting of water/ice or transition of the eutectic solution from liquid to solid are included in this phenomenological model. The lever rule is used to calculate the quantity of solution that undergoes the phase transformation, thereby simulating the energy released/absorbed during phase transformation. Undercooling and pore size effects are considered in the numerical model. To investigate the effect of pore size distribution, this distribution is considered using the Gibbs-Thomson equation in a saturated mortar specimen. For an air-entrained mortar, the impact of considering pore size (and curvature) on freezing was relatively insignificant; however the impact of pore size is much more significant during melting. The fluid inside pores smaller than 5 nm (i.e., gel pores) has a relatively small contribution in the macroscopic freeze-thaw behavior of mortar specimens within the temperature range used in this study (i.e., +24 °C to −35 °C), and can therefore be neglected for the macroscopic freeze-thaw simulations. A heat sink term is utilized to simulate the heat dissipation during phase transformations. Data from experiments performed using a low-temperature longitudinal guarded comparative calorimeter (LGCC) on mortar specimens fully saturated with various concentration NaCl solutions or partially saturated with water is compared to the numerical results and a promising agreement is generally obtained. PMID:28082830

The basic circuit of the IC: tectothalamic neurons with different patterns of synaptic organization send different messages to the thalamus

PubMed Central

Ito, Tetsufumi; Oliver, Douglas L.

2012-01-01

The inferior colliculus (IC) in the midbrain of the auditory system uses a unique basic circuit to organize the inputs from virtually all of the lower auditory brainstem and transmit this information to the medial geniculate body (MGB) in the thalamus. Here, we review the basic circuit of the IC, the neuronal types, the organization of their inputs and outputs. We specifically discuss the large GABAergic (LG) neurons and how they differ from the small GABAergic (SG) and the more numerous glutamatergic neurons. The somata and dendrites of LG neurons are identified by axosomatic glutamatergic synapses that are lacking in the other cell types and exclusively contain the glutamate transporter VGLUT2. Although LG neurons are most numerous in the central nucleus of the IC (ICC), an analysis of their distribution suggests that they are not specifically associated with one set of ascending inputs. The inputs to ICC may be organized into functional zones with different subsets of brainstem inputs, but each zone may contain the same three neuron types. However, the sources of VGLUT2 axosomatic terminals on the LG neuron are not known. Neurons in the dorsal cochlear nucleus, superior olivary complex, intermediate nucleus of the lateral lemniscus, and IC itself that express the gene for VGLUT2 only are the likely origin of the dense VGLUT2 axosomatic terminals on LG tectothalamic neurons. The IC is unique since LG neurons are GABAergic tectothalamic neurons in addition to the numerous glutamatergic tectothalamic neurons. SG neurons evidently target other auditory structures. The basic circuit of the IC and the LG neurons in particular, has implications for the transmission of information about sound through the midbrain to the MGB. PMID:22855671

Numerical Simulation of the Freeze-Thaw Behavior of Mortar Containing Deicing Salt Solution.

PubMed

Esmaeeli, Hadi S; Farnam, Yaghoob; Bentz, Dale P; Zavattieri, Pablo D; Weiss, Jason

2017-02-01

This paper presents a one-dimensional finite difference model that is developed to describe the freeze-thaw behavior of an air-entrained mortar containing deicing salt solution. A phenomenological model is used to predict the temperature and the heat flow for mortar specimens during cooling and heating. Phase transformations associated with the freezing/melting of water/ice or transition of the eutectic solution from liquid to solid are included in this phenomenological model. The lever rule is used to calculate the quantity of solution that undergoes the phase transformation, thereby simulating the energy released/absorbed during phase transformation. Undercooling and pore size effects are considered in the numerical model. To investigate the effect of pore size distribution, this distribution is considered using the Gibbs-Thomson equation in a saturated mortar specimen. For an air-entrained mortar, the impact of considering pore size (and curvature) on freezing was relatively insignificant; however the impact of pore size is much more significant during melting. The fluid inside pores smaller than 5 nm (i.e., gel pores) has a relatively small contribution in the macroscopic freeze-thaw behavior of mortar specimens within the temperature range used in this study (i.e., +24 °C to -35 °C), and can therefore be neglected for the macroscopic freeze-thaw simulations. A heat sink term is utilized to simulate the heat dissipation during phase transformations. Data from experiments performed using a low-temperature longitudinal guarded comparative calorimeter (LGCC) on mortar specimens fully saturated with various concentration NaCl solutions or partially saturated with water is compared to the numerical results and a promising agreement is generally obtained.

Ecological adaptation of wild peach palm, its in situ conservation and deforestation-mediated extinction in southern Brazilian Amazonia.

PubMed

Clement, Charles R; Santos, Ronaldo P; Desmouliere, Sylvain J M; Ferreira, Evandro J L; Neto, João Tomé Farias

2009-01-01

The Arc of Fire across southern Amazonia seasonally attracts worldwide attention as forests are cut and burned for agricultural expansion. These forests contain numerous wild relatives of native South American crops, such as peach palm. Our prospecting expeditions examined critical areas for wild peach palm in the Arc of Fire in Mato Grosso, Pará, Maranhão and Tocantins, as well as areas not previously examined in Amazonas and Amapá states. Recent digitization of the RADAM Brasil project permitted comparison among RADAM's parataxonomists' observations, previous botanical collections and our prospecting. Mapping on soils and vegetation types enabled us to hypothesize a set of ecological preferences. Wild peach palm is best adapted to Ultisols (Acrisols) in open forests across the Arc of Fire and westward into the more humid western Amazonia. Populations are generally small (fewer than 10 plants) on slopes above watercourses. In northern Mato Grosso and southern Pará soybean fields and pastures now occupy numerous areas where RADAM identified wild peach palm. The controversial BR-163 Highway is already eroding wild peach palm as deforestation expands. Many of these populations are now isolated by increasing forest fragmentation, which will lead to decreased reproduction via inbreeding depression and eventual extinction even without complete deforestation. Federal conservation areas are less numerous in the Arc of Fire than in other parts of Brazilian Amazonia, although there are indigenous lands; these conservation areas contain viable populations of wild peach palm and require better protection than they are currently receiving. Ex situ conservation of these populations is not viable given the relative lack of importance of domesticated peach palm and the difficulty of maintaining even economically interesting genetic resources.

Ecological Adaptation of Wild Peach Palm, Its In Situ Conservation and Deforestation-Mediated Extinction in Southern Brazilian Amazonia

PubMed Central

Clement, Charles R.; Santos, Ronaldo P.; Desmouliere, Sylvain J. M.; Ferreira, Evandro J. L.; Neto, João Tomé Farias

2009-01-01

Background The Arc of Fire across southern Amazonia seasonally attracts worldwide attention as forests are cut and burned for agricultural expansion. These forests contain numerous wild relatives of native South American crops, such as peach palm. Methodology/Principal Findings Our prospecting expeditions examined critical areas for wild peach palm in the Arc of Fire in Mato Grosso, Pará, Maranhão and Tocantins, as well as areas not previously examined in Amazonas and Amapá states. Recent digitization of the RADAM Brasil project permitted comparison among RADAM's parataxonomists' observations, previous botanical collections and our prospecting. Mapping on soils and vegetation types enabled us to hypothesize a set of ecological preferences. Wild peach palm is best adapted to Ultisols (Acrisols) in open forests across the Arc of Fire and westward into the more humid western Amazonia. Populations are generally small (fewer than 10 plants) on slopes above watercourses. In northern Mato Grosso and southern Pará soybean fields and pastures now occupy numerous areas where RADAM identified wild peach palm. The controversial BR-163 Highway is already eroding wild peach palm as deforestation expands. Conclusions/Significance Many of these populations are now isolated by increasing forest fragmentation, which will lead to decreased reproduction via inbreeding depression and eventual extinction even without complete deforestation. Federal conservation areas are less numerous in the Arc of Fire than in other parts of Brazilian Amazonia, although there are indigenous lands; these conservation areas contain viable populations of wild peach palm and require better protection than they are currently receiving. Ex situ conservation of these populations is not viable given the relative lack of importance of domesticated peach palm and the difficulty of maintaining even economically interesting genetic resources. PMID:19238213

Attempts at a numerical realisation of stochastic differential equations containing Preisach operator

NASA Astrophysics Data System (ADS)

McCarthy, S.; Rachinskii, D.

2011-01-01

We describe two Euler type numerical schemes obtained by discretisation of a stochastic differential equation which contains the Preisach memory operator. Equations of this type are of interest in areas such as macroeconomics and terrestrial hydrology where deterministic models containing the Preisach operator have been developed but do not fully encapsulate stochastic aspects of the area. A simple price dynamics model is presented as one motivating example for our studies. Some numerical evidence is given that the two numerical schemes converge to the same limit as the time step decreases. We show that the Preisach term introduces a damping effect which increases on the parts of the trajectory demonstrating a stronger upwards or downwards trend. The results are preliminary to a broader programme of research of stochastic differential equations with the Preisach hysteresis operator.

Influence of phytase and xylanase, individually or in combination, on performance, apparent metabolisable energy, digestive tract measurements and gut morphology in broilers fed wheat-based diets containing adequate level of phosphorus.

PubMed

Wu, Y B; Ravindran, V; Thomas, D G; Birtles, M J; Hendriks, W H

2004-02-01

1. The aim of the present study was to examine the influence of microbial phytase and xylanase, individually or in combination, on performance, apparent metabolisable energy, digesta viscosity, digestive tract measurements and gut morphology in broilers fed on wheat-soy diets containing adequate phosphorus (P). The wheat-soy basal diet was formulated to contain 4.5 g/kg non-phytate P and the experimental diets were formulated by supplementing the basal diet with xylanase (1000 xylanase units/kg diet), phytase (500 phytase units/kg diet) or a combination of phytase and xylanase. 2. Supplemental phytase improved the weight gains and feed efficiency by 17.5 and 2.9%, respectively. Corresponding improvements due to the addition of xylanase were 16.5 and 4.9%, respectively. The combination of phytase and xylanase caused no further improvements in broiler performance. 3. Individual additions of xylanase or phytase resulted in numerical improvements in apparent metabolisable energy (AME), but the differences were not significant. The combination of the two enzymes significantly increased AME. Addition of xylanase and the combination of the two enzymes reduced the viscosity of digesta in all sections of the intestine. Phytase supplementation reduced digesta viscosity in the duodenum and ileum, but not in the jejunum. 4. Enzyme supplementation lowered the relative weight and length of the small intestine. Additions of xylanase and phytase reduced the relative weight of the small intestine by 15.5 and 11.4%, respectively, while the corresponding reductions in the relative length of the small intestine were 16.5 and 14.1%, respectively. The combination of phytase and xylanase had no further effects on the relative weight and length of the small intestine compared with the xylanase group. 5. The addition of phytase increased villus height in the duodenum and decreased the number of goblet cells in the jejunum compared with those on the unsupplemented basal diet. Xylanase supplementation tended to increase goblet cell numbers in the duodenum and decreased crypt depth in thejejunum. The combination of phytase and xylanase increased villus height in the ileum and crypt depth in thejejunum and ileum. 6. In summary, the present results showed that the addition of a microbial phytase, produced by solid state fermentation and containing significant activities of beta-glucanase and xylanase, was as effective as xylanase in improving the performance of broiler chickens fed on wheat-based diets containing adequate levels of P. Improved performance with enzyme supplementation was generally associated with reduced digesta viscosity, increased AME, and reduced relative weight and length of small intestine.

Late Afternoon Sun

NASA Technical Reports Server (NTRS)

2002-01-01

[figure removed for brevity, see original site]

This image of the northern plains of Mars shows a surface texture of hundreds of small mounds and numerous small impact craters. The THEMIS imaging team is taking advantage of the late afternoon sun illumination to image places like this where the surface may contain small scale features that are 'washed-out' by higher illumination angles. As the sun dips towards the horizon (to the left side of the image), shadows are cast. The length of the shadows can be used to estimate the height of the feature casting them - or the depth of the crater that contains the shadow. In this image the craters - even very small ones - are now partially filled by shadow making it very easy to identify them. The small bumps are not casting shadows yet, but are easily seen. These small bumps were not easily identified when the sun angle was higher (earlier in the afternoon). As this image shows, late afternoon sun illumination is wonderful for making small scale morphologic features visible.

Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

Resonances and bound states in the continuum on periodic arrays of slightly noncircular cylinders

NASA Astrophysics Data System (ADS)

Hu, Zhen; Lu, Ya Yan

2018-02-01

Optical bound states in the continuum (BICs), especially those on periodic structures, have interesting properties and potentially important applications. Existing theoretical and numerical studies for optical BICs are mostly for idealized structures with simple and perfect geometric features, such as circular holes, rectangular cylinders and spheres. Since small distortions are always present in actual fabricated structures, we perform a high accuracy numerical study for BICs and resonances on a simple periodic structure with small distortions, i.e., periodic arrays of slightly noncircular cylinders. Our numerical results confirm that symmetries are important not only for the so-called symmetry-protected BICs, but also for the majority of propagating BICs which do not have a symmetry mismatch with the outgoing radiation waves. Typically, the BICs continue to exist if the small distortions keep the relevant symmetries, and they become resonant modes with finite quality factors if the small distortions break a required symmetry.

The Effects of Dissipation and Coarse Grid Resolution for Multigrid in Flow Problems

NASA Technical Reports Server (NTRS)

Eliasson, Peter; Engquist, Bjoern

1996-01-01

The objective of this paper is to investigate the effects of the numerical dissipation and the resolution of the solution on coarser grids for multigrid with the Euler equation approximations. The convergence is accomplished by multi-stage explicit time-stepping to steady state accelerated by FAS multigrid. A theoretical investigation is carried out for linear hyperbolic equations in one and two dimensions. The spectra reveals that for stability and hence robustness of spatial discretizations with a small amount of numerical dissipation the grid transfer operators have to be accurate enough and the smoother of low temporal accuracy. Numerical results give grid independent convergence in one dimension. For two-dimensional problems with a small amount of numerical dissipation, however, only a few grid levels contribute to an increased speed of convergence. This is explained by the small numerical dissipation leading to dispersion. Increasing the mesh density and hence making the problem over resolved increases the number of mesh levels contributing to an increased speed of convergence. If the steady state equations are elliptic, all grid levels contribute to the convergence regardless of the mesh density.

First Description of the Nymph and Larva of Dermacentor raskemensis (Acari: Ixodidae), Parasites of Pikas and Other Small Mammals in Central Asia

PubMed Central

Apanaskevich, Dmitry A.

2014-01-01

Dermacentor raskemensis Pomerantzev, 1946 is one of the rare Asian species in this genus. The immature stages of this species have never been described. Reexamination of D. raskemensis holdings stored in the United States National Tick Collection revealed a collection lot containing reared nymphs and larvae of this species. This collection made it possible for us to find numerous nymphs and larvae of D. raskemensis among previously unidentified material collected in the field. Both immature stages of D. raskemensis are described here for the first time. Nymphs of D. raskemensis can be distinguished from those of other Dermacentor species in the region by small spiracular plate, relatively short and obtuse lateral projections of basis capituli dorsally, relatively short spurs on coxa I and the internal spur is characteristically very broadly rounded at its apex, and very small spur on coxa IV, whereas larvae of D. raskemensis can be distinguished from other Dermacentor by relatively short and obtuse lateral projections of basis capituli, ≈6 denticles in the median files on hypostome, and relatively short, broad, and rounded spur on coxa I. The nymphs and larvae of D. raskemensis studied originate from Afghanistan, India, Iran, and Pakistan, where they were collected from pikas and other small mammals. PMID:24180099

Comparative analysis of the small RNA transcriptomes of Pinus contorta and Oryza sativa

PubMed Central

Morin, Ryan D.; Aksay, Gozde; Dolgosheina, Elena; Ebhardt, H. Alexander; Magrini, Vincent; Mardis, Elaine R.; Sahinalp, S. Cenk; Unrau, Peter J.

2008-01-01

The diversity of microRNAs and small-interfering RNAs has been extensively explored within angiosperms by focusing on a few key organisms such as Oryza sativa and Arabidopsis thaliana. A deeper division of the plants is defined by the radiation of the angiosperms and gymnosperms, with the latter comprising the commercially important conifers. The conifers are expected to provide important information regarding the evolution of highly conserved small regulatory RNAs. Deep sequencing provides the means to characterize and quantitatively profile small RNAs in understudied organisms such as these. Pyrosequencing of small RNAs from O. sativa revealed, as expected, ∼21- and ∼24-nt RNAs. The former contained known microRNAs, and the latter largely comprised intergenic-derived sequences likely representing heterochromatin siRNAs. In contrast, sequences from Pinus contorta were dominated by 21-nt small RNAs. Using a novel sequence-based clustering algorithm, we identified sequences belonging to 18 highly conserved microRNA families in P. contorta as well as numerous clusters of conserved small RNAs of unknown function. Using multiple methods, including expressed sequence folding and machine learning algorithms, we found a further 53 candidate novel microRNA families, 51 appearing specific to the P. contorta library. In addition, alignment of small RNA sequences to the O. sativa genome revealed six perfectly conserved classes of small RNA that included chloroplast transcripts and specific types of genomic repeats. The conservation of microRNAs and other small RNAs between the conifers and the angiosperms indicates that important RNA silencing processes were highly developed in the earliest spermatophytes. Genomic mapping of all sequences to the O. sativa genome can be viewed at http://microrna.bcgsc.ca/cgi-bin/gbrowse/rice_build_3/. PMID:18323537

Numerical methods for studying anharmonic oscillator approximations to the phi super 4 sub 2 quantum field theory

NASA Technical Reports Server (NTRS)

Isaacson, D.; Marchesin, D.; Paes-Leme, P. J.

1980-01-01

This paper is an expanded version of a talk given at the 1979 T.I.C.O.M. conference. It is a self-contained introduction, for applied mathematicians and numerical analysts, to quantum mechanics and quantum field theory. It also contains a brief description of the authors' numerical approach to the problems of quantum field theory, which may best be summarized by the question; Can we compute the eigenvalues and eigenfunctions of Schrodinger operators in infinitely many variables.

Three-dimensional baroclinic instability of a Hadley cell for small Richardson number

NASA Technical Reports Server (NTRS)

Antar, B. N.; Fowlis, W. W.

1985-01-01

A three-dimensional, linear stability analysis of a baroclinic flow for Richardson number, Ri, of order unity is presented. The model considered is a thin horizontal, rotating fluid layer which is subjected to horizontal and vertical temperature gradients. The basic state is a Hadley cell which is a solution of the complete set of governing, nonlinear equations and contains both Ekman and thermal boundary layers adjacent to the rigid boundaries; it is given in a closed form. The stability analysis is also based on the complete set of equations; and perturbation possessing zonal, meridional, and vertical structures were considered. Numerical methods were developed for the stability problem which results in a stiff, eighth-order, ordinary differential eigenvalue problem. The previous work on three-dimensional baroclinic instability for small Ri was extended to a more realistic model involving the Prandtl number, sigma, and the Ekman number, E, and to finite growth rates and a wider range of the zonal wavenumber.

Extending semi-numeric reionization models to the first stars and galaxies

NASA Astrophysics Data System (ADS)

Koh, Daegene; Wise, John H.

2018-03-01

Semi-numeric methods have made it possible to efficiently model the epoch of reionization (EoR). While most implementations involve a reduction to a simple three-parameter model, we introduce a new mass-dependent ionizing efficiency parameter that folds in physical parameters that are constrained by the latest numerical simulations. This new parametrization enables the effective modelling of a broad range of host halo masses containing ionizing sources, extending from the smallest Population III host haloes with M ˜ 106 M⊙, which are often ignored, to the rarest cosmic peaks with M ˜ 1012 M⊙ during EoR. We compare the resulting ionizing histories with a typical three-parameter model and also compare with the latest constraints from the Planck mission. Our model results in an optical depth due to Thomson scattering, τe = 0.057, that is consistent with Planck. The largest difference in our model is shown in the resulting bubble size distributions that peak at lower characteristic sizes and are broadened. We also consider the uncertainties of the various physical parameters, and comparing the resulting ionizing histories broadly disfavours a small contribution from galaxies. The smallest haloes cease a meaningful contribution to the ionizing photon budget after z = 10, implying that they play a role in determining the start of EoR and little else.

Surfactant enhanced recovery of tetrachloroethylene from a porous medium containing low permeability lenses. 2. Numerical simulation.

PubMed

Rathfelder, K M; Abriola, L M; Taylor, T P; Pennell, K D

2001-04-01

A numerical model of surfactant enhanced solubilization was developed and applied to the simulation of nonaqueous phase liquid recovery in two-dimensional heterogeneous laboratory sand tank systems. Model parameters were derived from independent, small-scale, batch and column experiments. These parameters included viscosity, density, solubilization capacity, surfactant sorption, interfacial tension, permeability, capillary retention functions, and interphase mass transfer correlations. Model predictive capability was assessed for the evaluation of the micellar solubilization of tetrachloroethylene (PCE) in the two-dimensional systems. Predicted effluent concentrations and mass recovery agreed reasonably well with measured values. Accurate prediction of enhanced solubilization behavior in the sand tanks was found to require the incorporation of pore-scale, system-dependent, interphase mass transfer limitations, including an explicit representation of specific interfacial contact area. Predicted effluent concentrations and mass recovery were also found to depend strongly upon the initial NAPL entrapment configuration. Numerical results collectively indicate that enhanced solubilization processes in heterogeneous, laboratory sand tank systems can be successfully simulated using independently measured soil parameters and column-measured mass transfer coefficients, provided that permeability and NAPL distributions are accurately known. This implies that the accuracy of model predictions at the field scale will be constrained by our ability to quantify soil heterogeneity and NAPL distribution.

HER2 isoforms co-expression differently tunes mammary tumor phenotypes affecting onset, vasculature and therapeutic response

PubMed Central

Balboni, Tania; Ianzano, Marianna L.; Laranga, Roberta; Landuzzi, Lorena; Giusti, Veronica; Ceccarelli, Claudio; Santini, Donatella; Taffurelli, Mario; Di Oto, Enrico; Asioli, Sofia; Amici, Augusto; Pupa, Serenella M.; De Giovanni, Carla; Tagliabue, Elda; Iezzi, Manuela; Nanni, Patrizia; Lollini, Pier-Luigi

2017-01-01

Full-length HER2 oncoprotein and splice variant Delta16 are co-expressed in human breast cancer. We studied their interaction in hybrid transgenic mice bearing human full-length HER2 and Delta16 (F1 HER2/Delta16) in comparison to parental HER2 and Delta16 transgenic mice. Mammary carcinomas onset was faster in F1 HER2/Delta16 and Delta16 than in HER2 mice, however tumor growth was slower, and metastatic spread was comparable in all transgenic mice. Full-length HER2 tumors contained few large vessels or vascular lacunae, whereas Delta16 tumors presented a more regular vascularization with numerous endothelium-lined small vessels. Delta16-expressing tumors showed a higher accumulation of i.v. injected doxorubicin than tumors expressing full-length HER2. F1 HER2/Delta16 tumors with high full-length HER2 expression made few large vessels, whereas tumors with low full-length HER2 and high Delta16 contained numerous small vessels and expressed higher levels of VEGF and VEGFR2. Trastuzumab strongly inhibited tumor onset in F1 HER2/Delta16 and Delta16 mice, but not in full-length HER2 mice. Addiction of F1 tumors to Delta16 was also shown by long-term stability of Delta16 levels during serial transplants, in contrast full-length HER2 levels underwent wide fluctuations. In conclusion, full-length HER2 leads to a faster tumor growth and to an irregular vascularization, whereas Delta16 leads to a faster tumor onset, with more regular vessels, which in turn could better transport cytotoxic drugs within the tumor, and to a higher sensitivity to targeted therapeutic agents. F1 HER2/Delta16 mice are a new immunocompetent mouse model, complementary to patient-derived xenografts, for studies of mammary carcinoma onset, prevention and therapy. PMID:28903354

Simulations of two sedimenting-interacting spheres with different sizes and initial configurations using immersed boundary method

NASA Astrophysics Data System (ADS)

Liao, Chuan-Chieh; Hsiao, Wen-Wei; Lin, Ting-Yu; Lin, Chao-An

2015-06-01

Numerical investigations are carried out for the drafting, kissing and tumbling (DKT) phenomenon of two freely falling spheres within a long container by using an immersed-boundary method. The method is first validated with flows induced by a sphere settling under gravity in a small container for which experimental data are available. The hydrodynamic interactions of two spheres are then studied with different sizes and initial configurations. When a regular sphere is placed below the larger one, the duration of kissing decreases in pace with the increase in diameter ratio. On the other hand, the time duration of the kissing stage increases in tandem with the increase in diameter ratio as the large sphere is placed below the regular one, and there is no DKT interactions beyond threshold diameter ratio. Also, the gap between homogeneous spheres remains constant at the terminal velocity, whereas the gaps between the inhomogeneous spheres increase due to the differential terminal velocity.

Geologic Mapping of V-19

NASA Technical Reports Server (NTRS)

Martin, Paula; Stofan, E. R.; Guest, J. E.

2010-01-01

A geologic map of the Sedna Planitia (V-19) quadrangle is being completed at 1:5,000,000 scale as part of the NASA Planetary Geologic Mapping Program, and will be submitted for review by September 2010. Overview: The Sedna Planitia quadrangle (V-19) extends from 25 N - 50 N latitude, 330 - 0 longitude. The quadrangle contains the northernmost portion of western Eistla Regio and the Sedna Planitia lowlands. Sedna Planitia consists of low-lying plains units, with numerous small volcanic edifices including shields, domes and cones. The quadrangle also contains several tholi, the large flowfield Neago Fluctus, the Manzan-Gurme Tesserae, and Zorile Dorsa and Karra-mahte Fossae which run NW-SE through the southwestern part of the quadrangle. There are six coronae in the quadrangle (Table 1), the largest of which is Nissaba (300 km x 220 km), and there are fourteen impact craters (Table 2). The V-19 quadrangle contains a variety of mappable volcanic landforms including two shield volcanoes (Evaki Tholus and Toci Tholus) and the southern portion of a large flow field (Neago Fluctus). A total of sixteen units associated with volcanoes have been mapped in this quadrangle, with multiple units mapped at Sif Mons, Sachs Patera and Neago Fluctus. An oddly textured, radarbright flow is also mapped in the Sedna plains, which appears to have originated from a several hundred kilometer long fissure. The six coronae within V-19 have a total of eighteen associated flow units. Several edifice fields are also mapped, in which the small volcanic edifices both predate and postdate the other units. Impact crater materials are also mapped.

30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

Trace metal analysis by laser ablation-inductively coupled plasmamass spectrometry and x-ray K-edge densitometry of forensic samples

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

Berry, Jonna Elizabeth

This dissertation describes a variety of studies on the determination of trace elements in samples with forensic importance. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) was used to determine the trace element composition of numerous lipstick samples. Lipstick samples were determined to be homogeneous. Most lipstick samples of similar colors were readily distinguishable at a 95% confidence interval based on trace element composition. Numerous strands of a multi-strand speaker cable were analyzed by LA-ICP-MS. The strands in this study are spatially heterogeneous in trace element composition. In actual forensic applications, the possibility of spatial heterogeneity must be considered, especially in casesmore » where only small samples (e.g., copper wire fragments after an explosion) are available. The effects of many unpredictable variables, such as weather, temperature, and human activity, on the retention of gunshot residue (GSR) around projectile wounds were assessed with LAICP- MS. Skin samples around gunshot and stab wounds and larvae feeding in and around the wounds on decomposing pig carcasses were analyzed for elements consistent with GSR (Sb, Pb, Ba, and Cu). These elements were detected at higher levels in skin and larvae samples around the gunshot wounds compared to the stab wounds for an extended period of time throughout decomposition in both a winter and summer study. After decomposition, radiographic images of the pig bones containing possible damage from bullets revealed metallic particles embedded within a number of bones. Metallic particles within the bones were analyzed with x-ray, K-edge densitometry and determined to contain lead, indicating that bullet residue can be retained throughout decomposition and detected within bones containing projectile trauma.« less

Interaction between numbers and size during visual search.

PubMed

Krause, Florian; Bekkering, Harold; Pratt, Jay; Lindemann, Oliver

2017-05-01

The current study investigates an interaction between numbers and physical size (i.e. size congruity) in visual search. In three experiments, participants had to detect a physically large (or small) target item among physically small (or large) distractors in a search task comprising single-digit numbers. The relative numerical size of the digits was varied, such that the target item was either among the numerically large or small numbers in the search display and the relation between numerical and physical size was either congruent or incongruent. Perceptual differences of the stimuli were controlled by a condition in which participants had to search for a differently coloured target item with the same physical size and by the usage of LCD-style numbers that were matched in visual similarity by shape transformations. The results of all three experiments consistently revealed that detecting a physically large target item is significantly faster when the numerical size of the target item is large as well (congruent), compared to when it is small (incongruent). This novel finding of a size congruity effect in visual search demonstrates an interaction between numerical and physical size in an experimental setting beyond typically used binary comparison tasks, and provides important new evidence for the notion of shared cognitive codes for numbers and sensorimotor magnitudes. Theoretical consequences for recent models on attention, magnitude representation and their interactions are discussed.

A second order radiative transfer equation and its solution by meshless method with application to strongly inhomogeneous media

NASA Astrophysics Data System (ADS)

Zhao, J. M.; Tan, J. Y.; Liu, L. H.

2013-01-01

A new second order form of radiative transfer equation (named MSORTE) is proposed, which overcomes the singularity problem of a previously proposed second order radiative transfer equation [J.E. Morel, B.T. Adams, T. Noh, J.M. McGhee, T.M. Evans, T.J. Urbatsch, Spatial discretizations for self-adjoint forms of the radiative transfer equations, J. Comput. Phys. 214 (1) (2006) 12-40 (where it was termed SAAI), J.M. Zhao, L.H. Liu, Second order radiative transfer equation and its properties of numerical solution using finite element method, Numer. Heat Transfer B 51 (2007) 391-409] in dealing with inhomogeneous media where some locations have very small/zero extinction coefficient. The MSORTE contains a naturally introduced diffusion (or second order) term which provides better numerical property than the classic first order radiative transfer equation (RTE). The stability and convergence characteristics of the MSORTE discretized by central difference scheme is analyzed theoretically, and the better numerical stability of the second order form radiative transfer equations than the RTE when discretized by the central difference type method is proved. A collocation meshless method is developed based on the MSORTE to solve radiative transfer in inhomogeneous media. Several critical test cases are taken to verify the performance of the presented method. The collocation meshless method based on the MSORTE is demonstrated to be capable of stably and accurately solve radiative transfer in strongly inhomogeneous media, media with void region and even with discontinuous extinction coefficient.

Time-dependent patterns in quasivertical cylindrical binary convection.

PubMed

Alonso, Arantxa; Mercader, Isabel; Batiste, Oriol

2018-02-01

This paper reports on numerical investigations of the effect of a slight inclination α on pattern formation in a shallow vertical cylindrical cell heated from below for binary mixtures with a positive value of the Soret coefficient. By using direct numerical simulation of the three-dimensional Boussinesq equations with Soret effect in cylindrical geometry, we show that a slight inclination of the cell in the range α≈0.036rad=2^{∘} strongly influences pattern selection. The large-scale shear flow (LSSF) induced by the small tilt of gravity overcomes the squarelike arrangements observed in noninclined cylinders in the Soret regime, stratifies the fluid along the direction of inclination, and produces an enhanced separation of the two components of the mixture. The competition between shear effects and horizontal and vertical buoyancy alters significantly the dynamics observed in noninclined convection. Additional unexpected time-dependent patterns coexist with the basic LSSF. We focus on an unsual periodic state recently discovered in an experiment, the so-called superhighway convection state (SHC), in which ascending and descending regions of fluid move in opposite directions. We provide numerical confirmation that Boussinesq Navier-Stokes equations with standard boundary conditions contain the essential ingredients that allow for the existence of such a state. Also, we obtain a persistent heteroclinic structure where regular oscillations between a SHC pattern and a state of nearly stationary longitudinal rolls take place. We characterize numerically these time-dependent patterns and investigate the dynamics around the threshold of convection.

Time-dependent patterns in quasivertical cylindrical binary convection

NASA Astrophysics Data System (ADS)

Alonso, Arantxa; Mercader, Isabel; Batiste, Oriol

2018-02-01

This paper reports on numerical investigations of the effect of a slight inclination α on pattern formation in a shallow vertical cylindrical cell heated from below for binary mixtures with a positive value of the Soret coefficient. By using direct numerical simulation of the three-dimensional Boussinesq equations with Soret effect in cylindrical geometry, we show that a slight inclination of the cell in the range α ≈0.036 rad =2∘ strongly influences pattern selection. The large-scale shear flow (LSSF) induced by the small tilt of gravity overcomes the squarelike arrangements observed in noninclined cylinders in the Soret regime, stratifies the fluid along the direction of inclination, and produces an enhanced separation of the two components of the mixture. The competition between shear effects and horizontal and vertical buoyancy alters significantly the dynamics observed in noninclined convection. Additional unexpected time-dependent patterns coexist with the basic LSSF. We focus on an unsual periodic state recently discovered in an experiment, the so-called superhighway convection state (SHC), in which ascending and descending regions of fluid move in opposite directions. We provide numerical confirmation that Boussinesq Navier-Stokes equations with standard boundary conditions contain the essential ingredients that allow for the existence of such a state. Also, we obtain a persistent heteroclinic structure where regular oscillations between a SHC pattern and a state of nearly stationary longitudinal rolls take place. We characterize numerically these time-dependent patterns and investigate the dynamics around the threshold of convection.

Gum arabic glycoprotein is a twisted hairy rope. A new model based on O-galactosylhydroxyproline as the polysaccharide attachment site

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

Wu Qi; Fong, C.; Lamport, D.T.A.

1991-07-01

Separation of the wound exudate from Acacia senegal (L.) Willd., gum arabic, on a preparative Superose-6 column gave two major fractions: a high molecular weight gum arabic glyco-protein (GAGP) containing about 90% carbohydrate and a lower molecular weight heterogeneous gum arabic polysaccharide fraction. Hydrogen fluoride-deglycosylation of GAGP gave a large hydroxyproline-rich polypeptide backbone (dGAGP). Alkaline hydrolysis of GAGP showed that most of the carbohydrate was attached to the polypeptide backbone as small hydroxyproline (Hyp)-polysaccharide substituents. The data imply a rodlike molecule with numerous small polysaccharide substituents (attached to 24% of the Hyp residues), regularly arranged along a highly periodic polypeptidemore » backbone based, hypothetically, on a 10 to 12 residue repetitive peptide motif. Thus, a simple statistical model of the gum arabic glycoprotein predicts a repeating polysaccharide substituents will maximize intramolecular hydrogen bonding if aligned along the long axis of the molecule, forming in effect a twisted hairy rope. Electron micrographs of rotary shadowed GAGP molecules support that prediction and may also explain show such apparently large molecules can exit the cell by endwise reptation through the small pores of the primary cell wall.« less

An Exact Separation of the Spin-Free and Spin-Dependent Terms of the Dirac-Coulomb-Breit Hamiltonian

NASA Technical Reports Server (NTRS)

Dyall, Kenneth G.

1994-01-01

The Dirac Hamiltonian is transformed by extracting the operator (sigma x p)/2mc from the small component of the wave function and applying it to the operators of the original Hamiltonian. The resultant operators contain products of Paull matrices that can be rearranged to give spin-free and spin-dependent operators. These operators are the ones encountered in the Breit-Pauli Hamiltonian, as well as some of higher order in alpha(sup 2). However, since the transformation of the original Dirac Hamiltonian is exact, the new Hamiltonian can be used in variational calculations, with or without the spin-dependent terms. The new small component functions have the same symmetry properties as the large component. Use of only the spin-free terms of the new Hamiltonian permits the same factorization over spin variables as in nonrelativistic theory, and therefore all the post-Self-Consistent Field (SCF) machinery of nonrelativistic calculations can be applied. However, the single-particle functions are two-component orbitals having a large and small component, and the SCF methods must be modified accordingly. Numerical examples are presented, and comparisons are made with the spin-free second-order Douglas-Kroll transformed Hamiltonian of Hess.

Proliferation resistance of small modular reactors fuels

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

Polidoro, F.; Parozzi, F.; Fassnacht, F.

2013-07-01

In this paper the proliferation resistance of different types of Small Modular Reactors (SMRs) has been examined and classified with criteria available in the literature. In the first part of the study, the level of proliferation attractiveness of traditional low-enriched UO{sub 2} and MOX fuels to be used in SMRs based on pressurized water technology has been analyzed. On the basis of numerical simulations both cores show significant proliferation risks. Although the MOX core is less proliferation prone in comparison to the UO{sub 2} core, it still can be highly attractive for diversion or undeclared production of nuclear material. Inmore » the second part of the paper, calculations to assess the proliferation attractiveness of fuel in typical small sodium cooled fast reactor show that proliferation risks from spent fuel cannot be neglected. The core contains a highly attractive plutonium composition during the whole life cycle. Despite some aspects of the design like the sealed core that enables easy detection of unauthorized withdrawal of fissile material and enhances proliferation resistance, in case of open Non-Proliferation Treaty break-out, weapon-grade plutonium in sufficient quantities could be extracted from the reactor core.« less

Numerical response of small vertebrates to prescribed fire in a California oak woodland

Treesearch

Justin K. Vreeland; William D. Tietje

2002-01-01

Use of prescribed fire for management of livestock forage and fuel load is increasing in California oak woodlands, but its effects on vertebrate wildlife are unknown. We conducted a light-intensity prescribed fire in mixed blue oak-coast live-oak woodlands in coastal-central California and assessed vegetation change and numerical response of small, non-game vertebrates...

Numerical response of small vertebrates to prescribed fire in California oak woodland

Treesearch

Justin K. Vreeland; William D. Tietje

2002-01-01

Use of prescribed fire is increasing in California oak woodlands, but its effects on vertebrate wildlife are unknown. We conducted a light-intensity prescribed fire in mixed blue oak?coast live-oak woodlands in coastal-central California and assessed vegetation change and numerical response of small, nongame vertebrates to the fire. Four of 13 vegetation and habitat...

Numerical viscosity and resolution of high-order weighted essentially nonoscillatory schemes for compressible flows with high Reynolds numbers.

PubMed

Zhang, Yong-Tao; Shi, Jing; Shu, Chi-Wang; Zhou, Ye

2003-10-01

A quantitative study is carried out in this paper to investigate the size of numerical viscosities and the resolution power of high-order weighted essentially nonoscillatory (WENO) schemes for solving one- and two-dimensional Navier-Stokes equations for compressible gas dynamics with high Reynolds numbers. A one-dimensional shock tube problem, a one-dimensional example with parameters motivated by supernova and laser experiments, and a two-dimensional Rayleigh-Taylor instability problem are used as numerical test problems. For the two-dimensional Rayleigh-Taylor instability problem, or similar problems with small-scale structures, the details of the small structures are determined by the physical viscosity (therefore, the Reynolds number) in the Navier-Stokes equations. Thus, to obtain faithful resolution to these small-scale structures, the numerical viscosity inherent in the scheme must be small enough so that the physical viscosity dominates. A careful mesh refinement study is performed to capture the threshold mesh for full resolution, for specific Reynolds numbers, when WENO schemes of different orders of accuracy are used. It is demonstrated that high-order WENO schemes are more CPU time efficient to reach the same resolution, both for the one-dimensional and two-dimensional test problems.

Macrocycles that inhibit the binding between heat shock protein 90 and TPR-containing proteins

PubMed Central

Ardi, Veronica C.; Alexander, Leslie D.; Johnson, Victoria; McAlpine, Shelli R.

2011-01-01

Heat shock protein 90 (Hsp90) accounts for 1–2% of the total proteins in normal cells and functions as a molecular chaperone that folds, assembles, and stabilizes client proteins. Hsp90 is over-expressed (3–6-fold increase) in stressed cells, including cancer cells, and regulates over 200 client and co-chaperone proteins. Hsp90 client proteins are involved in a plethora of cellular signaling events including numerous growth and apoptotic pathways. Since pathway-specific inhibitors can be problematic in drug-resistant cancers, shutting down multiple pathways at once is a promising approach when developing new therapeutics. Hsp90’s ability to modulate many growth and signaling pathways simultaneously makes this protein an attractive target in the field of cancer therapeutics. Herein we present evidence that a small molecule modulates Hsp90 via binding between the N and middle domain and allosterically inhibiting the binding interaction between Hsp90 and four C-terminal binding client proteins: IP6K2, FKBP38, FKBP52, and HOP. These last three clients contain a tetratricopeptide-repeat (TPR) region, which is known to interact with the MEEVD sequence on the C-terminus of Hsp90. Thus, this small molecule modulates the activity between co-chaperones that contain TPR motifs and Hsp90’s MEEVD region. This mechanism of action is unique from that of all Hsp90 inhibitors currently in clinical trials where these molecules have no effect on proteins that bind to the C-terminus of Hsp90. Further, our small molecule induces a Caspase-3 dependent apoptotic event. Thus, we describe the mechanism of a novel scaffold that is a useful tool for studying cell-signaling events that result when blocking the MEEVD-TPR interaction between Hsp90 and co-chaperone proteins. PMID:21950602

Vortex breakdown in closed containers with polygonal cross sections

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

Naumov, I. V., E-mail: naumov@itp.nsc.ru; Dvoynishnikov, S. V.; Kabardin, I. K.

2015-12-15

The vortex breakdown bubble in the confined flow generated by a rotating lid in closed containers with polygonal cross sections was analysed both experimentally and numerically for the height/radius aspect ratio equal to 2. The stagnation point locations of the breakdown bubble emergence and the corresponding Reynolds number were determined experimentally and in addition computed numerically by STAR-CCM+ CFD software for square, pentagonal, hexagonal, and octagonal cross section configurations. The flow pattern and the velocity were observed and measured by combining the seeding particle visualization and the temporal accuracy of laser Doppler anemometry. The vortex breakdown size and position onmore » the container axis were determined for Reynolds numbers, ranging from 1450 to 2400. The obtained results were compared with the flow structure in the closed container of cubical and cylindrical configurations. It is shown that the measured evolution of steady vortex breakdown is in close agreement with the numerical results.« less

Small field detector correction factors kQclin,Qmsr (fclin,fmsr) for silicon-diode and diamond detectors with circular 6 MV fields derived using both empirical and numerical methods.

PubMed

O'Brien, D J; León-Vintró, L; McClean, B

2016-01-01

The use of radiotherapy fields smaller than 3 cm in diameter has resulted in the need for accurate detector correction factors for small field dosimetry. However, published factors do not always agree and errors introduced by biased reference detectors, inaccurate Monte Carlo models, or experimental errors can be difficult to distinguish. The aim of this study was to provide a robust set of detector-correction factors for a range of detectors using numerical, empirical, and semiempirical techniques under the same conditions and to examine the consistency of these factors between techniques. Empirical detector correction factors were derived based on small field output factor measurements for circular field sizes from 3.1 to 0.3 cm in diameter performed with a 6 MV beam. A PTW 60019 microDiamond detector was used as the reference dosimeter. Numerical detector correction factors for the same fields were derived based on calculations from a geant4 Monte Carlo model of the detectors and the Linac treatment head. Semiempirical detector correction factors were derived from the empirical output factors and the numerical dose-to-water calculations. The PTW 60019 microDiamond was found to over-respond at small field sizes resulting in a bias in the empirical detector correction factors. The over-response was similar in magnitude to that of the unshielded diode. Good agreement was generally found between semiempirical and numerical detector correction factors except for the PTW 60016 Diode P, where the numerical values showed a greater over-response than the semiempirical values by a factor of 3.7% for a 1.1 cm diameter field and higher for smaller fields. Detector correction factors based solely on empirical measurement or numerical calculation are subject to potential bias. A semiempirical approach, combining both empirical and numerical data, provided the most reliable results.

Numerical and Experimental Study of a Cooling for Vanes in a Small Turbine Engine

NASA Astrophysics Data System (ADS)

Šimák, Jan; Michálek, Jan

2016-03-01

This paper is concerned with a cooling system for inlet guide vanes of a small turbine engine which are exposed to a high temperature gas leaving a combustion chamber. Because of small dimensions of the vanes, only a simple internal cavity and cooling holes can be realized. The idea was to utilize a film cooling technique. The proposed solution was simulated by means of a numerical method based on a coupling of CFD and heat transfer solvers. The numerical results of various scenarios (different coolant temperature, heat transfer to surroundings) showed a desired decrease of the temperature, especially on the most critical part - the trailing edge. The numerical data are compared to results obtained by experimental measurements performed in a test facility in our institute. A quarter segment model of the inlet guide vanes wheel was equipped with thermocouples in order to verify an effect of cooling. Despite some uncertainty in the results, a verifiable decrease of the vane temperature was observed.

Enhanced numerical analysis of three-color HgCdTe detectors

NASA Astrophysics Data System (ADS)

Jóźwikowski, K.; Rogalski, A.

2007-04-01

The performance of three-color HgCdTe photovoltaic heterostructure detector is examined theoretically. In comparison with two-color detectors with two back-to-back junctions, three-color structure contain an absorber of intermediate wavelength placed between two junctions, and electronic barriers are used to isolate this intermediate region. This structure was first proposed by British workers. Enhanced original computer programs are applied to solve the system of non-linear continuity equations for carriers and Poisson equations. In addition, the numerical analysis includes the dependence of absorption coefficient on Burstein effect as well as interference effects in heterostructure with metallic electrical contacts. Three detector structures with different localizations of separating barriers are analyzed. The calculations results are presented in the form of spatial distributions of bandgap energy and quantum efficiency. It is shown that the performance of the detector is critically dependent on the barrier's doping level and position in relation to the junction. This behavior is serious disadvantage of the considered three color detector. A small shift of the barrier location and doping level causes serious changes in spectral responsivity.

Numerical analysis of three-colour HgCdTe detectors

NASA Astrophysics Data System (ADS)

Jóźwikowski, K.; Rogalski, A.

2007-12-01

The performance of three-colour HgCdTe photovoltaic heterostructure detector is examined theoretically. In comparison with two-colour detectors with two back-to-back junctions, three-colour structure contains an absorber of intermediate wavelength placed between two junctions and electronic barriers are used to isolate this intermediate region. This structure was first proposed by British workers. Three-detector structures with different localizations of separating barriers are analyzed. The calculation results are presented in the form of spatial distributions of bandgap energy and quantum efficiency. Enhanced original computer programs are applied to solve the system of non-linear continuity equations for carriers and Poisson equations. In addition, the numerical analysis includes the dependence of absorption coefficient on Burstein effect as well as interference effects in heterostructure with metallic electrical contacts. It is shown that the performance of the detector is critically dependent on the barrier’s doping level and position in relation to the junction. This behaviour is serious disadvantage of the considered three-colour detector. A small shift of the barrier location and doping level causes serious changes in spectral responsivity.

Encounter with Saturn: Voyager 1 imaging science results

USGS Publications Warehouse

Smith, B.A.; Soderblom, L.; Beebe, R.; Boyce, J.; Briggs, G.; Bunker, A.; Collins, S.A.; Hansen, C.J.; Johnson, T.V.; Mitchell, J.L.; Terrile, R.J.; Carr, M.; Cook, A.F.; Cuzzi, J.; Pollack, James B.; Danielson, G. Edward; Ingersoll, A.; Davies, M.E.; Hunt, G.E.; Masursky, H.; Shoemaker, E.; Morrison, D.; Owen, Timothy W.; Sagan, C.; Veverka, J.; Strom, R.; Suomi, V.E.

1981-01-01

As Voyager 1 flew through the Saturn system it returned photographs revealing many new and surprising characteristics of this complicated community of bodies. Saturn's atmosphere has numerous, low-contrast, discrete cloud features and a pattern of circulation significantly different from that of Jupiter. Titan is shrouded in a haze layer that varies in thickness and appearance. Among the icy satellites there is considerable variety in density, albedo, and surface morphology and substantial evidence for endogenic surface modification. Trends in density and crater characteristics are quite unlike those of the Galilean satellites. Small inner satellites, three of which were discovered in Voyager images, interact gravitationally with one another and with the ring particles in ways not observed elsewhere in the solar system. Saturn's broad A, B, and C rings contain hundreds of "ringlets," and in the densest portion of the B ring there are numerous nonaxisymmetric features. The narrow F ring has three components which, in at least one instance, are kinked and crisscrossed. Two rings are observed beyond the F ring, and material is seen between the C ring and the planet. Copyright ?? 1981 AAAS.

Pancreatic Abscess in a cat due to Staphylococcus aureus infection.

PubMed

Nemoto, Yuki; Haraguchi, Tomoya; Shimokawa Miyama, Takako; Kobayashi, Kosuke; Hama, Kaori; Kurogouchi, Yosuke; Fujiki, Noriyuki; Baba, Kenji; Okuda, Masaru; Mizuno, Takuya

2017-07-07

A 16-year-old spayed female American Shorthair cat was presented with lethargy, anorexia, and wamble. Physical and blood examination did not reveal any remarkable findings. Abdominal ultrasonography identified the presence of a localized anechoic structure with a thick wall in contact with the small intestine and adjacent to the liver. Ultrasound-guided fine-needle aspiration of the structure revealed fluid containing numerous cocci and neutrophils. Two days after antibiotic treatment, exploratory laparotomy was performed and the content of the structure was removed before multiple lavages. The pathological and bacteriological examination results supported a confirmatory diagnosis of pancreatic abscess due to Staphylococcus aureus infection, making this the first such report in a cat. The cat remained healthy thereafter with no disease recurrence.

Simulation of sea surface wave influence on small target detection with airborne laser depth sounding.

PubMed

Tulldahl, H Michael; Steinvall, K Ove

2004-04-20

A theoretical model for simulation of airborne depth-sounding lidar is presented with the purpose of analyzing the influence from water surface waves on the ability to detect 1-m3 targets placed on the sea bottom. Although water clarity is the main limitation, sea surface waves can significantly affect the detectability. The detection probability for a target at a 9-m depth can be above 90% at 1-m/s wind and below 80% at 6-m/s wind for the same water clarity. The simulation model contains both numerical and analytical components. Simulated data are compared with measured data and give realistic results for bottom depths between 3 and 10 m.

Entamoeba sp. (Sarcomastigophora: Endamoebidae) from ostriches (Struthio camelus) (Aves: Struthionidae).

PubMed

Martínez-Díaz, R A; Herrera, S; Castro, A; Ponce, F

2000-10-01

The first case of Entamoeba of the 1-nucleate mature cyst group in birds is described. Trophozoites and cysts of Entamoeba have been found in ostriches (Struthio camelus) from farms located all over Spain. The cysts are large (13.47microm mean diameter); they possess one nucleus when mature, with a large endosome and peripheral chromatine arranged in small granules; chromatoid bodies, when present, are large and elongated. Trophozoites are large (19. 88microm mean diameter), with a clear differentiation between ecto- and endoplasm, this containing numerous vacuoles; the nucleus is large and diffuse. The characteristics of this amoeba resembles but do not completely fulfill those of E. suis and E. chattoni; also, these species are from mammals.

GlobiPack v. 1.0

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

Bartlett, Roscoe

2010-03-31

GlobiPack contains a small collection of optimization globalization algorithms. These algorithms are used by optimization and various nonlinear equation solver algorithms.Used as the line-search procedure with Newton and Quasi-Newton optimization and nonlinear equation solver methods. These are standard published 1-D line search algorithms such as are described in the book Nocedal and Wright Numerical Optimization: 2nd edition, 2006. One set of algorithms were copied and refactored from the existing open-source Trilinos package MOOCHO where the linear search code is used to globalize SQP methods. This software is generic to any mathematical optimization problem where smooth derivatives exist. There is nomore » specific connection or mention whatsoever to any specific application, period. You cannot find more general mathematical software.« less

A catalog of 0.2 A resolution far-ultraviolet stellar spectra measured with Copernicus

NASA Technical Reports Server (NTRS)

Snow, T. P., Jr.; Jenkins, E. B.

1977-01-01

Spectra between 1000 and 1450 A for 60 O- and B-type stars observed by Copernicus at 0.2-A resolution are presented in three forms: tables containing the numerical data, plots showing renormalized spectra, and synthetic photographic spectra. The data have been corrected for all instrument effects of importance for the photometric accuracy except fluctuations in continuum level caused by small variations in spacecraft guidance. Spectrometer sensitivity curves are provided for use in converting to absolute fluxes. It is expected that this catalog will be of use for research on many aspects of stellar UV spectra, including spectral classification, line identification, abundance determinations, spectrum synthesis, model atmosphere calculations, flux distributions, bolometric corrections, stellar winds, and mass loss.

Versatile roles of extracellular vesicles in cancer

PubMed Central

Kosaka, Nobuyoshi; Yoshioka, Yusuke; Fujita, Yu

2016-01-01

Numerous studies have shown that non–cell-autonomous regulation of cancer cells is an important aspect of tumorigenesis. Cancer cells need to communicate with stromal cells by humoral factors such as VEGF, FGFs, and Wnt in order to survive. Recently, extracellular vesicles (EVs) have also been shown to be involved in cell-cell communication between cancer cells and the surrounding microenvironment and to be important for the development of cancer. In addition, these EVs contain small noncoding RNAs, including microRNAs (miRNAs), which contribute to the malignancy of cancer cells. Here, we provide an overview of current research on EVs, especially miRNAs in EVs. We also propose strategies to treat cancers by targeting EVs around cancer cells. PMID:26974161

The function and evolution of Msx genes: pointers and paradoxes.

PubMed

Davidson, D

1995-10-01

The Msx genes of vertebrates comprise a small family of chromosomally unlinked homeobox-containing genes related to the Drosophila gene muscle-segment homeobox (msh). Despite their ancient pedigree, the Msx genes are expressed in a range of vertebrate-specific tissues, including neural crest, cranial sensory placodes, bone and teeth. They are active in numerous systems, which have been used as models to study pattern formation and tissue interaction, and are, therefore, attracting a growing interest among developmental biologists. But beyond their presumed role as transcription factors, we do not know what their functions are in the cell or the embryo. Here, I review recent evidence that is beginning to address this problem and might eventually increase our understanding of how the vertebrate embryo has evolved.

A review of dietary fiber and health: focus on raisins.

PubMed

Bell, Stacey J

2011-09-01

Fibers vary in their physiologic effects. For example, viscous fibers may delay gastric emptying of ingested foods into the small intestine, creating a sensation of fullness; reduce blood glucose concentrations; and potentially benefit insulin sensitivity. They also improve blood cholesterol levels. Insoluble fibers are poorly absorbed and are known to improve fecal bulk and laxation and ameliorate constipation. Despite these numerous benefits, most Americans do not get enough of either kind of fiber in the diet. Some have argued that fiber-rich foods are not appetizing and therefore avoided. Raisins contain both forms of fiber and have a sweet flavor. This review provides support for consuming adequate fiber in the diet and suggests a role for raisins to help increase total dietary fiber.

The speed of sound in a gas–vapour bubbly liquid

PubMed Central

Prosperetti, Andrea

2015-01-01

In addition to the vapour of the liquid, bubbles in cavitating flows usually contain also a certain amount of permanent gas that diffuses out of the liquid as they grow. This paper presents a simplified linear model for the propagation of monochromatic pressure waves in a bubbly liquid with these characteristics. Phase change effects are included in detail, while the gas is assumed to follow a polytropic law. It is shown that even a small amount of permanent gas can have a major effect on the behaviour of the system. Particular attention is paid to the low-frequency range, which is of special concern in flow cavitation. Numerical results for water and liquid oxygen illustrate the implications of the model. PMID:26442146

The speed of sound in a gas-vapour bubbly liquid.

PubMed

Prosperetti, Andrea

2015-10-06

In addition to the vapour of the liquid, bubbles in cavitating flows usually contain also a certain amount of permanent gas that diffuses out of the liquid as they grow. This paper presents a simplified linear model for the propagation of monochromatic pressure waves in a bubbly liquid with these characteristics. Phase change effects are included in detail, while the gas is assumed to follow a polytropic law. It is shown that even a small amount of permanent gas can have a major effect on the behaviour of the system. Particular attention is paid to the low-frequency range, which is of special concern in flow cavitation. Numerical results for water and liquid oxygen illustrate the implications of the model.

On the Importance of Small Ice Crystals in Tropical Anvil Cirrus

NASA Technical Reports Server (NTRS)

Jensen, E. J.; Lawson, P.; Baker, B.; Pilson, B.; Mo, Q.; Heymsfield, A. J.; Bansemer, A.; Bui, T. P.; McGill, M.; Hlavka, D.;

Numerical Development

ERIC Educational Resources Information Center

Siegler, Robert S.; Braithwaite, David W.

2016-01-01

In this review, we attempt to integrate two crucial aspects of numerical development: learning the magnitudes of individual numbers and learning arithmetic. Numerical magnitude development involves gaining increasingly precise knowledge of increasing ranges and types of numbers: from non-symbolic to small symbolic numbers, from smaller to larger…

Spacecraft Re-Entry Impact Point Targeting Using Aerodynamic Drag

NASA Technical Reports Server (NTRS)

Omar, Sanny R.; Bevilacqua, Riccardo

2017-01-01

The ability to re-enter the atmosphere at a desired location is important for spacecraft containing components that may survive re-entry. While impact point targeting has traditionally been initiated through impulsive burns with chemical thrusters on large vehicles such as the Space Shuttle, and the Soyuz and Apollo capsules, many small spacecraft do not host thrusters and require an alternative means of impact point targeting to ensure that falling debris do not cause harm to persons or property. This paper discusses the use of solely aerodynamic drag force to perform this targeting. It is shown that by deploying and retracting a drag device to vary the ballistic coefficient of the spacecraft, any desired longitude and latitude on the ground can be targeted provided that the maneuvering begins early enough and the latitude is less than the inclination of the orbit. An analytical solution based on perturbations from a numerically propagated trajectory is developed to map the initial state and ballistic coefficient profile of a spacecraft to its impact point. This allows the ballistic coefficient profile necessary to reach a given target point to be rapidly calculated, making it feasible to generate the guidance for the decay trajectory onboard the spacecraft. The ability to target an impact point using aerodynamic drag will enhance the capabilities of small spacecraft and will enable larger space vehicles containing thrusters to save fuel by more effectively leveraging the available aerodynamic drag.

Modelling turbulent boundary layer flow over fractal-like multiscale terrain using large-eddy simulations and analytical tools.

PubMed

Yang, X I A; Meneveau, C

2017-04-13

In recent years, there has been growing interest in large-eddy simulation (LES) modelling of atmospheric boundary layers interacting with arrays of wind turbines on complex terrain. However, such terrain typically contains geometric features and roughness elements reaching down to small scales that typically cannot be resolved numerically. Thus subgrid-scale models for the unresolved features of the bottom roughness are needed for LES. Such knowledge is also required to model the effects of the ground surface 'underneath' a wind farm. Here we adapt a dynamic approach to determine subgrid-scale roughness parametrizations and apply it for the case of rough surfaces composed of cuboidal elements with broad size distributions, containing many scales. We first investigate the flow response to ground roughness of a few scales. LES with the dynamic roughness model which accounts for the drag of unresolved roughness is shown to provide resolution-independent results for the mean velocity distribution. Moreover, we develop an analytical roughness model that accounts for the sheltering effects of large-scale on small-scale roughness elements. Taking into account the shading effect, constraints from fundamental conservation laws, and assumptions of geometric self-similarity, the analytical roughness model is shown to provide analytical predictions that agree well with roughness parameters determined from LES.This article is part of the themed issue 'Wind energy in complex terrains'. © 2017 The Author(s).

Numerical study of the small scale structures in Boussinesq convection

NASA Technical Reports Server (NTRS)

Weinan, E.; Shu, Chi-Wang

1992-01-01

Two-dimensional Boussinesq convection is studied numerically using two different methods: a filtered pseudospectral method and a high order accurate Essentially Nonoscillatory (ENO) scheme. The issue whether finite time singularity occurs for initially smooth flows is investigated. The numerical results suggest that the collapse of the bubble cap is unlikely to occur in resolved calculations. The strain rate corresponding to the intensification of the density gradient across the front saturates at the bubble cap. We also found that the cascade of energy to small scales is dominated by the formulation of thin and sharp fronts across which density jumps.

Method for preparing small volume reaction containers

DOEpatents

Retterer, Scott T.; Doktycz, Mitchel J.

2017-04-25

Engineered reaction containers that can be physically and chemically defined to control the flux of molecules of different sizes and charge are disclosed. Methods for constructing small volume reaction containers through a combination of etching and deposition are also disclosed. The methods allow for the fabrication of multiple devices that possess features on multiple length scales, specifically small volume containers with controlled porosity on the nanoscale.

Subcellular localization of calcium deposits in the noble crayfish Astacus astacus spermatophore: Implications for post-mating spermatophore hardening and spermatozoon maturation.

PubMed

Niksirat, Hamid; Kouba, Antonín

2016-04-01

The freshly ejaculated spermatophore of crayfish undergoes a hardening process during post-mating storage on the body surface of female. The ultrastructural distribution of calcium deposits were studied and compared in freshly ejaculated and post-mating noble crayfish spermatophores, using the oxalate-pyroantimonate technique, to determine possible roles of calcium in post-mating spermatophore hardening and spermatozoon maturation. Small particles of sparsely distributed calcium deposits were visible in the wall of freshly ejaculated spermatophore. Also, large amount of calcium deposits were visible in the membranes of the freshly ejaculated spermatozoon. Five minutes post-ejaculation, granules in the spermatophore wall appeared as porous formations with numerous electron lucent spaces. Calcium deposits were visible within the spaces and scattered in the spermatophore wall matrix, where smaller calcium deposits combined to form globular calcium deposits. Large numbers of the globular calcium deposits were visible in the wall of the post-mating spermatophore. Smaller calcium deposits were detected in the central area of post-mating spermatophore, which contains the sperm mass, and in the extracellular matrix and capsule. While the density of calcium deposits decreased in the post-mating spermatozoon membranes, numerous small calcium deposits appeared in the subacrosomal zone and nucleus. Substantial changes in calcium deposit distribution in the crayfish spermatophore during post-mating storage on the body of female may be involved in the processes of the spermatophore hardening and spermatozoon maturation. © 2016 Wiley Periodicals, Inc.

Fine structure of the pecten oculi of the barred owl (Strix varia).

PubMed

Smith, B J; Smith, S A; Braekevelt, C R

1996-01-01

The pecten oculi of the barred owl (Strix varia) has been examined by light and transmission electron microscopy. The pecten in this species is of the pleated type and is small in comparison to the size of the ocular globe. The pecten consists of 8-10 accordion-like folds that are linked apically by a pigmented tissue bridge. Each fold contains numerous capillaries, larger supply and drainage vessels, and abundant pleomorphic melanocytes. Most of these capillaries are extremely specialized vessels that possess plentiful microfolds on both the luminal and abluminal surfaces. Some capillaries however display only a few microfolds. The endothelial cell bodies are extremely attenuated, with most organelles located near the nucleus. All capillaries are surrounded by a very thick fibrillar basal lamina, which is thought to provide structural support to these small vessels. Pericytes are commonly found within these thickened basal laminae. Numerous melanocytes are also present, with processes that form an incomplete sheath around the capillaries. These processes are also presumed to provide structural support for the capillaries. As in other avian species, the morphology of the barred owl pecten is indicative of extensive involvement in substance transport. When compared to the pecten of more visually-oriented species, this pecten is smaller, has fewer folds, and displays a reduced number of microfolds within the capillaries. In these and other features, the barred owl pecten is similar to the pecten of the great horned owl (Bubo virginianus).

Cognitive Strategy Use and Measured Numeric Ability in Immediate- and Long-Term Recall of Everyday Numeric Information

PubMed Central

Bermingham, Douglas; Hill, Robert D.; Woltz, Dan; Gardner, Michael K.

2013-01-01

The goals of this study were to assess the primary effects of the use of cognitive strategy and a combined measure of numeric ability on recall of every-day numeric information (i.e. prices). Additionally, numeric ability was assessed as a moderator in the relationship between strategy use and memory for prices. One hundred participants memorized twelve prices that varied from 1 to 6 digits; they recalled these immediately and after 7 days. The use of strategies, assessed through self-report, was associated with better overall recall, but not forgetting. Numeric ability was not associated with either better overall recall or forgetting. A small moderating interaction was found, in which higher levels of numeric ability enhanced the beneficial effects of strategy use on overall recall. Exploratory analyses found two further small moderating interactions: simple strategy use enhanced overall recall at higher levels of numeric ability, compared to complex strategy use; and complex strategy use was associated with lower levels of forgetting, but only at higher levels of numeric ability, compared to the simple strategy use. These results provide support for an objective measure of numeric ability, as well as adding to the literature on memory and the benefits of cognitive strategy use. PMID:23483964

Cognitive strategy use and measured numeric ability in immediate- and long-term recall of everyday numeric information.

PubMed

Bermingham, Douglas; Hill, Robert D; Woltz, Dan; Gardner, Michael K

2013-01-01

The goals of this study were to assess the primary effects of the use of cognitive strategy and a combined measure of numeric ability on recall of every-day numeric information (i.e. prices). Additionally, numeric ability was assessed as a moderator in the relationship between strategy use and memory for prices. One hundred participants memorized twelve prices that varied from 1 to 6 digits; they recalled these immediately and after 7 days. The use of strategies, assessed through self-report, was associated with better overall recall, but not forgetting. Numeric ability was not associated with either better overall recall or forgetting. A small moderating interaction was found, in which higher levels of numeric ability enhanced the beneficial effects of strategy use on overall recall. Exploratory analyses found two further small moderating interactions: simple strategy use enhanced overall recall at higher levels of numeric ability, compared to complex strategy use; and complex strategy use was associated with lower levels of forgetting, but only at higher levels of numeric ability, compared to the simple strategy use. These results provide support for an objective measure of numeric ability, as well as adding to the literature on memory and the benefits of cognitive strategy use.

Variation in predicting pantograph-catenary interaction contact forces, numerical simulations and field measurements

NASA Astrophysics Data System (ADS)

Nåvik, Petter; Rønnquist, Anders; Stichel, Sebastian

2017-09-01

The contact force between the pantograph and the contact wire ensures energy transfer between the two. Too small of a force leads to arching and unstable energy transfer, while too large of a force leads to unnecessary wear on both parts. Thus, obtaining the correct contact force is important for both field measurements and estimates using numerical analysis. The field contact force time series is derived from measurements performed by a self-propelled diagnostic vehicle containing overhead line recording equipment. The measurements are not sampled at the actual contact surface of the interaction but by force transducers beneath the collector strips. Methods exist for obtaining more realistic measurements by adding inertia and aerodynamic effects to the measurements. The variation in predicting the pantograph-catenary interaction contact force is studied in this paper by evaluating the effect of the force sampling location and the effects of signal processing such as filtering. A numerical model validated by field measurements is used to study these effects. First, this paper shows that the numerical model can reproduce a train passage with high accuracy. Second, this study introduces three different options for contact force predictions from numerical simulations. Third, this paper demonstrates that the standard deviation and the maximum and minimum values of the contact force are sensitive to a low-pass filter. For a specific case, an 80 Hz cut-off frequency is compared to a 20 Hz cut-off frequency, as required by EN 50317:2012; the results show an 11% increase in standard deviation, a 36% increase in the maximum value and a 19% decrease in the minimum value.

On Sums of Numerical Series and Fourier Series

ERIC Educational Resources Information Center

Pavao, H. Germano; de Oliveira, E. Capelas

2008-01-01

We discuss a class of trigonometric functions whose corresponding Fourier series, on a conveniently chosen interval, can be used to calculate several numerical series. Particular cases are presented and two recent results involving numerical series are recovered. (Contains 1 note.)

Pelton turbine Needle erosion prediction based on 3D three- phase flow simulation

NASA Astrophysics Data System (ADS)

Chongji, Z.; Yexiang, X.; Wei, Z.; Yangyang, Y.; Lei, C.; Zhengwei, W.

2014-03-01

Pelton turbine, which applied to the high water head and small flow rate, is widely used in the mountainous area. During the operation period the sediment contained in the water does not only induce the abrasion of the buckets, but also leads to the erosion at the nozzle which may damage the needle structure. The nozzle and needle structure are mainly used to form high quality cylindrical jet and increase the efficiency of energy exchange in the runner to the most. Thus the needle erosion will lead to the deformation of jet, and then may cause the efficiency loss and cavitation. The favourable prediction of abrasion characteristic of needle can effectively guide the optimization design and maintenance of needle structure. This paper simulated the unsteady three-dimensional multi-phase flow in the nozzle and injected jet flow. As the jet containing water and sediment is injected into the free atmosphere air with high velocity, the VOF model was adopted to predict the water and air flow. The sediment is simplified into round solid particle and the discrete particle model (DPM) was employed to predict the needle abrasion characteristic. The sand particle tracks were analyzed to interpret the mechanism of sand erosion on the needle surface. And the numerical result of needle abrasion was obtained and compared with the abrasion field observation. The similarity of abrasion pattern between the numerical results and field observation illustrated the validity of the 3D multi-phase flow simulation method.

Muscular innervation of the proximal duodenum of the guinea pig.

PubMed

Iino, S

2000-10-01

We investigated the muscular structure and innervation of the gastroduodenal junction in the guinea pig. In the gastroduodenal junction, the innermost layer of the circular muscle contained numerous nerve fibers and terminals. Since this nerve network continued onto the deep muscular plexus (DMP) of the duodenum, we surmised that the numerous nerve fibers in the gastroduodenal junction were specialized DMP in the most proximal part of the duodenum. The innermost layer containing many nerve fibers was about 1,000 microm in length and 100 microm in thickness in the proximal duodenum. This layer contained numerous connective tissue fibers composed of collagen and elastic fibers. Five to 30 smooth muscle cells lay in contact with each other and were surrounded by fine connective tissue. The nerve fibers in the proximal duodenum contained nerve terminals immunoreactive for choline acetyltransferase, dynorphin, enkephalin, galanin, gastrin-releasing peptide, nitric oxide synthase, substance P, and vasoactive intestinal polypeptide. Adrenergic fibers which contained tyrosine hydroxylase immunoreactivity were rare in the proximal duodenum. In the innermost layer of the proximal duodenum, there were numerous c-Kit immunopositive cells that were in contact with nerve terminals. This study allowed us to clarify the specific architecture of the most proximal portion of the duodenum. The functional significance of the proximal duodenum in relation to the electrical connection and neural cooperation of the musculature between the antrum and the duodenum is also discussed.

77 FR 31727 - Approval and Promulgation of Air Quality Implementation Plans; Illinois; Small Container...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-30

... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R05-OAR-2012-0073; FRL 9677-3] Approval and Promulgation of Air Quality Implementation Plans; Illinois; Small Container Exemption From VOC Coating Rules...), direct final rule approving a revision to the Illinois SIP that added a ``small container exemption'' for...

40 CFR 265.316 - Disposal of small containers of hazardous waste in overpacked drums (lab packs).

Code of Federal Regulations, 2010 CFR

2010-07-01

... OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Landfills § 265.316 Disposal of small containers of hazardous waste in overpacked drums (lab packs). Small containers of hazardous waste... hazardous waste in overpacked drums (lab packs). 265.316 Section 265.316 Protection of Environment...

40 CFR 264.316 - Disposal of small containers of hazardous waste in overpacked drums (lab packs).

Code of Federal Regulations, 2010 CFR

2010-07-01

... HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Landfills § 264.316 Disposal of small containers of hazardous waste in overpacked drums (lab packs). Small containers of hazardous waste in overpacked... hazardous waste in overpacked drums (lab packs). 264.316 Section 264.316 Protection of Environment...

Helicity Evolution at Small x

NASA Astrophysics Data System (ADS)

Sievert, Michael; Kovchegov, Yuri; Pitonyak, Daniel

2017-01-01

We construct small- x evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the g1 structure function. These evolution equations resum powers of ln2(1 / x) in the polarization-dependent evolution along with the powers of ln(1 / x) in the unpolarized evolution which includes saturation effects. The equations are written in an operator form in terms of polarization-dependent Wilson line-like operators. While the equations do not close in general, they become closed and self-contained systems of non-linear equations in the large-Nc and large-Nc &Nf limits. After solving the large-Nc equations numerically we obtain the following small- x asymptotics for the flavor-singlet g1 structure function along with quarks hPDFs and helicity TMDs (in absence of saturation effects): g1S(x ,Q2) ΔqS(x ,Q2) g1L S(x ,kT2) (1/x) > αh (1/x) 2.31√{αsNc/2 π. We also give an estimate of how much of the proton's spin may be at small x and what impact this has on the so-called ``spin crisis.'' Work supported by the U.S. DOE, Office of Science, Office of Nuclear Physics under Award Number DE-SC0004286 (YK), the RIKEN BNL Research Center, and TMD Collaboration (DP), and DOE Contract No. DE-SC0012704 (MS).

The regional abundance and size distribution of lakes and reservoirs in the United States and implication for estimates of global lake extent

USGS Publications Warehouse

McDonald, Cory P.; Rover, Jennifer; Stets, Edward G.; Striegl, Robert G.

2012-01-01

We analyzed complete geospatial data for the 3.5 million lakes and reservoirs larger than 0.001 km2, with a combined surface area of 131,000 km2, in the contiguous United States (excluding the Laurentian Great Lakes) and identified their regional distribution characteristics. For Alaska, we also analyzed (1) incomplete data that suggest that the state contains 1–2.5 million lakes larger than 0.001 km2 covering over 50,000 km2 and (2) localized high-resolution (5 m) data that suggest that the number of very small water bodies (< 0.001 km2) may be comparable with the number of lakes > 0.001 km2 in some areas. The Pareto distribution cannot accurately describe the lake abundance-size relationship across the entire size spectrum, and extrapolation of this density function to small size classes has likely resulted in the overestimation of the number of small lakes in the world. While small water bodies dominate in terms of numbers, they are not numerous enough to dominate in terms of surface area, as has been previously suggested. Extending our results to the global scale suggests that there are on the order of 64 million water bodies larger than 0.001 km2 in the world, with a total surface area of approximately 3.8 million km2.

A numerical study of the interaction between unsteady free-stream disturbances and localized variations in surface geometry

NASA Technical Reports Server (NTRS)

Bodonyi, R. J.; Tadjfar, M.; Welch, W. J. C.; Duck, P. W.

1989-01-01

A numerical study of the generation of Tollmien-Schlichting (T-S) waves due to the interaction between a small free-stream disturbance and a small localized variation of the surface geometry has been carried out using both finite-difference and spectral methods. The nonlinear steady flow is of the viscous-inviscid interactive type while the unsteady disturbed flow is assumed to be governed by the Navier-Stokes equations linearized about this flow. Numerical solutions illustrate the growth or decay of the T-S waves generated by the interaction between the free-stream disturbance and the surface distortion, depending on the value of the scaled Strouhal number. An important result of this receptivity problem is the numerical determination of the amplitude of the T-S waves.

Combined Uncertainty and A-Posteriori Error Bound Estimates for General CFD Calculations: Theory and Software Implementation

NASA Technical Reports Server (NTRS)

Barth, Timothy J.

2014-01-01

This workshop presentation discusses the design and implementation of numerical methods for the quantification of statistical uncertainty, including a-posteriori error bounds, for output quantities computed using CFD methods. Hydrodynamic realizations often contain numerical error arising from finite-dimensional approximation (e.g. numerical methods using grids, basis functions, particles) and statistical uncertainty arising from incomplete information and/or statistical characterization of model parameters and random fields. The first task at hand is to derive formal error bounds for statistics given realizations containing finite-dimensional numerical error [1]. The error in computed output statistics contains contributions from both realization error and the error resulting from the calculation of statistics integrals using a numerical method. A second task is to devise computable a-posteriori error bounds by numerically approximating all terms arising in the error bound estimates. For the same reason that CFD calculations including error bounds but omitting uncertainty modeling are only of limited value, CFD calculations including uncertainty modeling but omitting error bounds are only of limited value. To gain maximum value from CFD calculations, a general software package for uncertainty quantification with quantified error bounds has been developed at NASA. The package provides implementations for a suite of numerical methods used in uncertainty quantification: Dense tensorization basis methods [3] and a subscale recovery variant [1] for non-smooth data, Sparse tensorization methods[2] utilizing node-nested hierarchies, Sampling methods[4] for high-dimensional random variable spaces.

Finger gnosis predicts a unique but small part of variance in initial arithmetic performance.

PubMed

Wasner, Mirjam; Nuerk, Hans-Christoph; Martignon, Laura; Roesch, Stephanie; Moeller, Korbinian

2016-06-01

Recent studies indicated that finger gnosis (i.e., the ability to perceive and differentiate one's own fingers) is associated reliably with basic numerical competencies. In this study, we aimed at examining whether finger gnosis is also a unique predictor for initial arithmetic competencies at the beginning of first grade-and thus before formal math instruction starts. Therefore, we controlled for influences of domain-specific numerical precursor competencies, domain-general cognitive ability, and natural variables such as gender and age. Results from 321 German first-graders revealed that finger gnosis indeed predicted a unique and relevant but nevertheless only small part of the variance in initial arithmetic performance (∼1%-2%) as compared with influences of general cognitive ability and numerical precursor competencies. Taken together, these results substantiated the notion of a unique association between finger gnosis and arithmetic and further corroborate the theoretical idea of finger-based representations contributing to numerical cognition. However, the only small part of variance explained by finger gnosis seems to limit its relevance for diagnostic purposes. Copyright © 2016. Published by Elsevier Inc.

You can count on the motor cortex: Finger counting habits modulate motor cortex activation evoked by numbers

PubMed Central

Tschentscher, Nadja; Hauk, Olaf; Fischer, Martin H.; Pulvermüller, Friedemann

2012-01-01

The embodied cognition framework suggests that neural systems for perception and action are engaged during higher cognitive processes. In an event-related fMRI study, we tested this claim for the abstract domain of numerical symbol processing: is the human cortical motor system part of the representation of numbers, and is organization of numerical knowledge influenced by individual finger counting habits? Developmental studies suggest a link between numerals and finger counting habits due to the acquisition of numerical skills through finger counting in childhood. In the present study, digits 1 to 9 and the corresponding number words were presented visually to adults with different finger counting habits, i.e. left- and right-starters who reported that they usually start counting small numbers with their left and right hand, respectively. Despite the absence of overt hand movements, the hemisphere contralateral to the hand used for counting small numbers was activated when small numbers were presented. The correspondence between finger counting habits and hemispheric motor activation is consistent with an intrinsic functional link between finger counting and number processing. PMID:22133748

Two populations of glutamatergic axons in the rat dorsal raphe nucleus defined by the vesicular glutamate transporters 1 and 2.

PubMed

Commons, Kathryn G; Beck, Sheryl G; Bey, Vincent W

2005-03-01

Most glutamatergic neurons in the brain express one of two vesicular glutamate transporters, vGlut1 or vGlut2. Cortical glutamatergic neurons highly express vGlut1, whereas vGlut2 predominates in subcortical areas. In this study immunohistochemical detection of vGlut1 or vGlut2 was used in combination with tryptophan hydroxylase (TPH) to characterize glutamatergic innervation of the dorsal raphe nucleus (DRN) of the rat. Immunofluorescence labeling of both vGlut1 and vGlut2 was punctate and homogenously distributed throughout the DRN. Puncta labeled for vGlut2 appeared more numerous then those labeled for vGlut1. Ultrastructural analysis revealed axon terminals containing vGlut1 and vGlut2 formed asymmetric-type synapses 80% and 95% of the time, respectively. Postsynaptic targets of vGlut1- and vGlut2-containing axons differed in morphology. vGlut1-labeled axon terminals synapsed predominantly on small-caliber (distal) dendrites (42%, 46/110) or dendritic spines (46%, 50/110). In contrast, vGlut2-containing axons synapsed on larger caliber (proximal) dendritic shafts (> 0.5 microm diameter; 48%, 78/161). A fraction of both vGlut1- or vGlut2-labeled axons synapsed onto TPH-containing dendrites (14% and 34%, respectively). These observations reveal that different populations of glutamate-containing axons innervate selective dendritic domains of serotonergic and non-serotonergic neurons, suggesting they play different functional roles in modulating excitation within the DRN.

Use of qualitative and quantitative information in neural networks for assessing agricultural chemical contamination of domestic wells

USGS Publications Warehouse

Mishra, A.; Ray, C.; Kolpin, D.W.

2004-01-01

A neural network analysis of agrichemical occurrence in groundwater was conducted using data from a pilot study of 192 small-diameter drilled and driven wells and 115 dug and bored wells in Illinois, a regional reconnaissance network of 303 wells across 12 Midwestern states, and a study of 687 domestic wells across Iowa. Potential factors contributing to well contamination (e.g., depth to aquifer material, well depth, and distance to cropland) were investigated. These contributing factors were available in either numeric (actual or categorical) or descriptive (yes or no) format. A method was devised to use the numeric and descriptive values simultaneously. Training of the network was conducted using a standard backpropagation algorithm. Approximately 15% of the data was used for testing. Analysis indicated that training error was quite low for most data. Testing results indicated that it was possible to predict the contamination potential of a well with pesticides. However, predicting the actual level of contamination was more difficult. For pesticide occurrence in drilled and driven wells, the network predictions were good. The performance of the network was poorer for predicting nitrate occurrence in dug and bored wells. Although the data set for Iowa was large, the prediction ability of the trained network was poor, due to descriptive or categorical input parameters, compared with smaller data sets such as that for Illinois, which contained more numeric information.

A characteristics-based method for solving the transport equation and its application to the process of mantle differentiation and continental root growth

NASA Astrophysics Data System (ADS)

de Smet, Jeroen H.; van den Berg, Arie P.; Vlaar, Nico J.; Yuen, David A.

2000-03-01

Purely advective transport of composition is of major importance in the Geosciences, and efficient and accurate solution methods are needed. A characteristics-based method is used to solve the transport equation. We employ a new hybrid interpolation scheme, which allows for the tuning of stability and accuracy through a threshold parameter ɛth. Stability is established by bilinear interpolations, and bicubic splines are used to maintain accuracy. With this scheme, numerical instabilities can be suppressed by allowing numerical diffusion to work in time and locally in space. The scheme can be applied efficiently for preliminary modelling purposes. This can be followed by detailed high-resolution experiments. First, the principal effects of this hybrid interpolation method are illustrated and some tests are presented for numerical solutions of the transport equation. Second, we illustrate that this approach works successfully for a previously developed continental evolution model for the convecting upper mantle. In this model the transport equation contains a source term, which describes the melt production in pressure-released partial melting. In this model, a characteristic phenomenon of small-scale melting diapirs is observed (De Smet et al.1998; De Smet et al. 1999). High-resolution experiments with grid cells down to 700m horizontally and 515m vertically result in highly detailed observations of the diapiric melting phenomenon.

Classification and phagocytosis of circulating haemocytes in Chinese mitten crab (Eriocheir sinensis) and the effect of extrinsic stimulation on circulating haemocytes in vivo.

PubMed

Lv, Sunjian; Xu, Jiehao; Zhao, Jing; Yin, Na; Lu, Binjie; Li, Song; Chen, Yuyin; Xu, Haisheng

2014-08-01

Eriocheir sinensis (Henri Milne Edwards 1854) is one of the most important aquaculture species in China. In this investigation, we characterised the different types of haemocytes of E. sinensis using light and electron microscopy combined with cytochemical analysis and determined the in vivo phagocytic ability of different haemocyte types by injecting polystyrene beads. The haemocytes of E. sinensis were divided into three types: hyalinocytes, semigranulocytes and granulocytes. The hyalinocytes had no or few cytoplasmic granules; the semigranulocytes contained abundant small granules and a few large refractile cytoplasmic granules; and the granulocytes contained numerous large refractile cytoplasmic granules. The hyalinocytes were demonstrated to be the most abundant circulating haemocytes and the most avid phagocytic haemocytes, accounting for approximately 88.7% of the total phagocytes. The haemocyte-containing granules displayed limited phagocytic ability, with approximately 5.0% of granulocytes and 6.3% of semigranulocytes displaying positive phagocytic ability against the invading polystyrene beads in vivo. After injection with Aeromonas hydrophila, Bacillus subtilis and different concentrations of lipopolysaccharide for 0.25, 0.5, 1, 2, 4, 6 and 8 h, all three types of haemocytes experienced dramatic decline and then rapid recovery to their initial levels. A high concentration of lipopolysaccharide and A. hydrophila were extremely toxic to the crabs, as they induced a more serious loss of haemocytes compared with a low concentration of lipopolysaccharide and B. subtilis. Overall, the results obtained in this study indicate that a small proportion of the haemocytes of E. sinensis contributed to the phagocytic process, and the migration of haemocytes and haemocyte lysis were most likely a prominent pathway for pathogen elimination. Copyright © 2014 Elsevier Ltd. All rights reserved.

Stage-dependent remodeling of the nuclear envelope and lamina during rabbit early embryonic development.

PubMed

Popken, Jens; Schmid, Volker J; Strauss, Axel; Guengoer, Tuna; Wolf, Eckhard; Zakhartchenko, Valeri

2016-04-22

Utilizing 3D structured illumination microscopy, we investigated the quality and quantity of nuclear invaginations and the distribution of nuclear pores during rabbit early embryonic development and identified the exact time point of nucleoporin 153 (NUP153) association with chromatin during mitosis. Contrary to bovine early embryonic nuclei, featuring almost exclusively nuclear invaginations containing a small volume of cytoplasm, nuclei in rabbit early embryonic stages show additionally numerous invaginations containing a large volume of cytoplasm. Small-volume invaginations frequently emanated from large-volume nuclear invaginations but not vice versa, indicating a different underlying mechanism. Large- and small-volume nuclear envelope invaginations required the presence of chromatin, as they were restricted to chromatin-positive areas. The chromatin-free contact areas between nucleolar precursor bodies (NPBs) and large-volume invaginations were free of nuclear pores. Small-volume invaginations were not in contact with NPBs. The number of invaginations and isolated intranuclear vesicles per nucleus peaked at the 4-cell stage. At this stage, the nuclear surface showed highly concentrated clusters of nuclear pores surrounded by areas free of nuclear pores. Isolated intranuclear lamina vesicles were usually NUP153 negative. Cytoplasmic, randomly distributed NUP153-positive clusters were highly abundant at the zygote stage and decreased in number until they were almost absent at the 8-cell stage and later. These large NUP153 clusters may represent a maternally provided NUP153 deposit, but they were not visible as clusters during mitosis. Major genome activation at the 8- to 16-cell stage may mark the switch from a necessity for a deposit to on-demand production. NUP153 association with chromatin is initiated during metaphase before the initiation of the regeneration of the lamina. To our knowledge, the present study demonstrates for the first time major remodeling of the nuclear envelope and its underlying lamina during rabbit preimplantation development.

SPLICE: A program to assemble partial query solutions from three-dimensional database searches into novel ligands

NASA Astrophysics Data System (ADS)

Ho, Chris M. W.; Marshall, Garland R.

1993-12-01

SPLICE is a program that processes partial query solutions retrieved from 3D, structural databases to generate novel, aggregate ligands. It is designed to interface with the database searching program FOUNDATION, which retrieves fragments containing any combination of a user-specified minimum number of matching query elements. SPLICE eliminates aspects of structures that are physically incapable of binding within the active site. Then, a systematic rule-based procedure is performed upon the remaining fragments to ensure receptor complementarity. All modifications are automated and remain transparent to the user. Ligands are then assembled by linking components into composite structures through overlapping bonds. As a control experiment, FOUNDATION and SPLICE were used to reconstruct a know HIV-1 protease inhibitor after it had been fragmented, reoriented, and added to a sham database of fifty different small molecules. To illustrate the capabilities of this program, a 3D search query containing the pharmacophoric elements of an aspartic proteinase-inhibitor crystal complex was searched using FOUNDATION against a subset of the Cambridge Structural Database. One hundred thirty-one compounds were retrieved, each containing any combination of at least four query elements. Compounds were automatically screened and edited for receptor complementarity. Numerous combinations of fragments were discovered that could be linked to form novel structures, containing a greater number of pharmacophoric elements than any single retrieved fragment.

Spatial attention determines the nature of nonverbal number representation.

PubMed

Hyde, Daniel C; Wood, Justin N

2011-09-01

Coordinated studies of adults, infants, and nonhuman animals provide evidence for two systems of nonverbal number representation: a "parallel individuation" system that represents individual items and a "numerical magnitude" system that represents the approximate cardinal value of a group. However, there is considerable debate about the nature and functions of these systems, due largely to the fact that some studies show a dissociation between small (1-3) and large (>3) number representation, whereas others do not. Using event-related potentials, we show that it is possible to determine which system will represent the numerical value of a small number set (1-3 items) by manipulating spatial attention. Specifically, when attention can select individual objects, an early brain response (N1) scales with the cardinal value of the display, the signature of parallel individuation. In contrast, when attention cannot select individual objects or is occupied by another task, a later brain response (P2p) scales with ratio, the signature of the approximate numerical magnitude system. These results provide neural evidence that small numbers can be represented as approximate numerical magnitudes. Further, they empirically demonstrate the importance of early attentional processes to number representation by showing that the way in which attention disperses across a scene determines which numerical system will deploy in a given context.

Large eddy simulation of turbine wakes using higher-order methods

NASA Astrophysics Data System (ADS)

Deskos, Georgios; Laizet, Sylvain; Piggott, Matthew D.; Sherwin, Spencer

2017-11-01

Large eddy simulations (LES) of a horizontal-axis turbine wake are presented using the well-known actuator line (AL) model. The fluid flow is resolved by employing higher-order numerical schemes on a 3D Cartesian mesh combined with a 2D Domain Decomposition strategy for an efficient use of supercomputers. In order to simulate flows at relatively high Reynolds numbers for a reasonable computational cost, a novel strategy is used to introduce controlled numerical dissipation to a selected range of small scales. The idea is to mimic the contribution of the unresolved small-scales by imposing a targeted numerical dissipation at small scales when evaluating the viscous term of the Navier-Stokes equations. The numerical technique is shown to behave similarly to the traditional eddy viscosity sub-filter scale models such as the classic or the dynamic Smagorinsky models. The results from the simulations are compared to experimental data for a Reynolds number scaled by the diameter equal to ReD =1,000,000 and both the time-averaged stream wise velocity and turbulent kinetic energy (TKE) are showing a good overall agreement. At the end, suggestions for the amount of numerical dissipation required by our approach are made for the particular case of horizontal-axis turbine wakes.

Epithelial stem cells are formed by small-particles released from particle-producing cells

PubMed Central

Kong, Wuyi; Zhu, Xiao Ping; Han, Xiu Juan; Nuo, Mu; Wang, Hong

2017-01-01

Recent spatiotemporal report demonstrated that epidermal stem cells have equal potential to divide or differentiate, with no asymmetric cell division observed. Therefore, how epithelial stem cells maintain lifelong stem-cell support still needs to be elucidated. In mouse blood and bone marrow, we found a group of large cells stained strongly for eosin and containing coiled-tubing-like structures. Many were tightly attached to each other to form large cellular clumps. After sectioning, these large cell-clumps were composed of not cells but numerous small particles, however with few small “naked” nuclei. The small particles were about 2 to 3 μm in diameter and stained dense red for eosin, so they may be rich in proteins. Besides the clumps composed of small particles, we identified clumps formed by fusion of the small particles and clumps of newly formed nucleated cells. These observations suggest that these small particles further fused and underwent cellularization. E-cadherin was expressed in particle-fusion areas, some “naked” nuclei and the newly formed nucleated cells, which suggests that these particles can form epithelial cells via fusion and nuclear remodeling. In addition, we observed similar-particle fusion before epithelial cellularization in mouse kidney ducts after kidney ischemia, which suggests that these particles can be released in the blood and carried to the target tissues for epithelial-cell regeneration. Oct4 and E-cadherin expressed in the cytoplasmic areas in cells that were rich in protein and mainly located in the center of the cellular clumps, suggesting that these newly formed cells have become tissue-specific epithelial stem cells. Our data provide evidence that these large particle-producing cells are the origin of epithelial stem cells. The epithelial stem cells are newly formed by particle fusion. PMID:28253358

A multilayer shallow water system for polydisperse sedimentation

NASA Astrophysics Data System (ADS)

Fernández-Nieto, E. D.; Koné, E. H.; Morales de Luna, T.; Bürger, R.

2013-04-01

This work considers the flow of a fluid containing one disperse substance consisting of small particles that belong to different species differing in size and density. The flow is modelled by combining a multilayer shallow water approach with a polydisperse sedimentation process. This technique allows one to keep information on the vertical distribution of the solid particles in the mixture, and thereby to model the segregation of the particle species from each other, and from the fluid, taking place in the vertical direction of the gravity body force only. This polydisperse sedimentation process is described by the well-known Masliyah-Lockett-Bassoon (MLB) velocity functions. The resulting multilayer sedimentation-flow model can be written as a hyperbolic system with nonconservative products. The definitions of the nonconservative products are related to the hydrostatic pressure and to the mass and momentum hydrodynamic transfer terms between the layers. For the numerical discretization a strategy of two steps is proposed, where the first one is also divided into two parts. In the first step, instead of approximating the complete model, we approximate a reduced model with a smaller number of unknowns. Then, taking advantage of the fact that the concentrations are passive scalars in the system, we approximate the concentrations of the different species by an upwind scheme related to the numerical flux of the total concentration. In the second step, the effect of the transference terms defined in terms of the MLB model is introduced. These transfer terms are approximated by using a numerical flux function used to discretize the 1D vertical polydisperse model, see Bürger et al. [ R. Bürger, A. García, K.H. Karlsen, J.D. Towers, A family of numerical schemes for kinematic flows with discontinuous flux, J. Eng. Math. 60 (2008) 387-425]. Finally, some numerical examples are presented. Numerical results suggest that the multilayer shallow water model could be adequate in situations where the settling takes place from a suspension that undergoes horizontal movement.

The Good, the Bad, and the Ugly: Numerical Prediction for Hurricane Juan (2003)

NASA Astrophysics Data System (ADS)

Gyakum, J.; McTaggart-Cowan, R.

2004-05-01

The range of accuracy of the numerical weather prediction (NWP) guidance for the landfall of Hurricane Juan (2003), from nearly perfect to nearly useless, motivates a study of the NWP forecast errors on 28-29 September 2003 in the eastern North Atlantic. Although the forecasts issued over the period were of very high quality, this is primarily because of the diligence of the forecasters, and not related to the reliability of the numerical predictions provided to them by the North American operational centers and the research community. A bifurcation in the forecast fields from various centers and institutes occurred beginning with the 0000 UTC run of 28 September, and continuing until landfall just after 0000 UTC on 29 September. The GFS (NCEP), Eta (NCEP), GEM (Canadian Meteorological Centre; CMC), and MC2 (McGill) forecast models all showed an extremely weak (minimum SLP above 1000 hPa) remnant vortex moving north-northwestward into the Gulf of Maine and merging with a diabatically-developed surface low offshore. The GFS uses a vortex-relocation scheme, the Eta a vortex bogus, and the GEM and MC2 are run on CMC analyses that contain no enhanced vortex. The UK Met Office operational, the GFDL, and the NOGAPS (US Navy) forecast models all ran a small-scale hurricane-like vortex directly into Nova Scotia and verified very well for this case. The UKMO model uses synthetic observations to enhance structures in poorly-forecasted areas during the analysis cycle and both the GFDL and NOGAPS model use advanced idealized vortex bogusing in their initial conditions. The quality of the McGill MC2 forecast is found to be significantly enhanced using a bogusing technique similar to that used in the initialization of the successful forecast models. A verification of the improved forecast is presented along with a discussion of the need for operational quality control of the background fields in the analysis cycle and for proper representation of strong, small-scale tropical vortices.

Shocks in oscillated granular layers

NASA Astrophysics Data System (ADS)

Bougie, J.; Moon, Sung Joon; Swift, J. B.; Swinney, Harry L.

2001-11-01

We study shock formation in vertically oscillated granular layers, where shock waves form with each collision between the layer and the bottom plate of the container. We use both three-dimensional numerical solutions of continuum equations developed by Jenkins and Richman (J.T. Jenkins and M.W. Richman, Arch. Rat. Mech. Anal. 87), 355 (1985) for smooth and nearly elastic hard spheres, and previously validated molecular dynamics (MD) simulations (C. Bizon, M.D. Shattuck, J.B. Swift, W.D. McCormick, and H.L. Swinney, Phys. Rev. Lett. 80), 57 (1998). Both methods capture the shock formation, and the two methods agree quantitatively for small dissipation. We also investigate the effect of inelasticity on shock formation, and use both smooth and rough hard-sphere MD simulations to investigate the effect of friction in this system.

Radiative flux from a planar multiple point source within a cylindrical enclosure reaching a coaxial circular plane

NASA Astrophysics Data System (ADS)

Tryka, Stanislaw

2007-04-01

A general formula and some special integral formulas were presented for calculating radiative fluxes incident on a circular plane from a planar multiple point source within a coaxial cylindrical enclosure perpendicular to the source. These formula were obtained for radiation propagating in a homogeneous isotropic medium assuming that the lateral surface of the enclosure completely absorbs the incident radiation. Exemplary results were computed numerically and illustrated with three-dimensional surface plots. The formulas presented are suitable for determining fluxes of radiation reaching planar circular detectors, collectors or other planar circular elements from systems of laser diodes, light emitting diodes and fiber lamps within cylindrical enclosures, as well as small biological emitters (bacteria, fungi, yeast, etc.) distributed on planar bases of open nontransparent cylindrical containers.

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

Scherrer, Arne; UMR 8640 ENS-CNRS-UPMC, Département de Chimie, 24 rue Lhomond, École Normale Supérieure, 75005 Paris; UPMC Université Paris 06, 4, Place Jussieu, 75005 Paris

The nuclear velocity perturbation theory (NVPT) for vibrational circular dichroism (VCD) is derived from the exact factorization of the electron-nuclear wave function. This new formalism offers an exact starting point to include correction terms to the Born-Oppenheimer (BO) form of the molecular wave function, similar to the complete-adiabatic approximation. The corrections depend on a small parameter that, in a classical treatment of the nuclei, is identified as the nuclear velocity. Apart from proposing a rigorous basis for the NVPT, we show that the rotational strengths, related to the intensity of the VCD signal, contain a new contribution beyond-BO that canmore » be evaluated with the NVPT and that only arises when the exact factorization approach is employed. Numerical results are presented for chiral and non-chiral systems to test the validity of the approach.« less

Mammographic and sonographic findings of steatocystoma multiplex presenting as breast lumps.

PubMed

Wan, John Mun Chin; Wong, Jill Su Lin; Tee, Shang-Ian

2012-12-01

Steatocystoma multiplex (SM) is an uncommon cutaneous disorder characterised by multiple intradermal cysts distributed over the trunk and proximal extremities. This condition affects both genders and is often inherited as an autosomal dominant trait, although sporadic cases have been described. This report describes the mammographic and sonographic features of the cysts, which presented as breast lumps, for evaluation. The cysts appeared as numerous well-circumscribed, radiolucent nodules with thin radiodense rims on mammography. On sonography, the cysts could be hypoechoic, isoechoic or demonstrate mixed echoes containing debris-fluid levels, depending on the amount of clear oily liquid and keratinous material. SM can be diagnosed based on a clinical setting of multiple asymptomatic small intradermal nodules over the trunk and proximal extremities, positive family history and imaging findings.

Pencil-like mm-size electron beams produced with linear inductive voltage adders

NASA Astrophysics Data System (ADS)

Mazarakis, M. G.; Poukey, J. W.; Rovang, D. C.; Maenchen, J. E.; Cordova, S. R.; Menge, P. R.; Pepping, R.; Bennett, L.; Mikkelson, K.; Smith, D. L.; Halbleib, J.; Stygar, W. A.; Welch, D. R.

1997-02-01

We present the design, analysis, and results of the high brightness electron beam experiments currently under investigation at Sandia National Laboratories. The anticipated beam parameters are the following: energy 12 MeV, current 35-40 kA, rms radius 0.5 mm, and pulse duration 40 ns full width at half-maximum. The accelerator is SABRE, a pulsed linear inductive voltage adder modified to higher impedance, and the electron source is a magnetically immersed foilless electron diode. 20-30 T solenoidal magnets are required to insulate the diode and contain the beam to its extremely small-sized (1 mm) envelope. These experiments are designed to push the technology to produce the highest possible electron current in a submillimeter radius beam. Design, numerical simulations, and experimental results are presented.

Magnetization processes in core/shell exchange-spring structures.

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

Jiang, J. S.

2015-03-27

The magnetization reversal processes in cylindrical and spherical soft core/hard shell exchange-spring structures are investigated via the analytical nucleation theory, and are verified with numerical micromagnetic simulations. At small core sizes, the nucleation of magnetic reversal proceeds via the modified bulging mode, where the transverse component of the magnetization is only semi-coherent in direction and the nucleation field contains a contribution from self-demagnetization. For large core sizes, the modified curling mode, where the magnetization configuration is vortex-like, is favored at nucleation. The preference for the modified curling mode is beneficial in that the fluxclosure allows cylindrical and spherical core/shell exchange-springmore » elements to be densely packed into bulk permanent magnets without affecting the nucleation field, thereby offering the potential for high energy product.« less

Discovery of skin alkaloids in a miniaturized eleutherodactylid frog from Cuba.

PubMed

Rodríguez, Ariel; Poth, Dennis; Schulz, Stefan; Vences, Miguel

2011-06-23

Four phylogenetically independent lineages of frogs are currently known to sequester lipid-soluble skin alkaloids for which a dietary source has been demonstrated. We report here a remarkable fifth such instance, in Eleutherodactylus iberia and Eleutherodactylus orientalis, two species of miniaturized frogs of the family Eleutherodactylidae from Cuba. Six pumiliotoxins and two indolizidines were found in E. iberia, one of the smallest frogs in the world and characterized by a contrasting colour pattern for which we hypothesize an aposematic function. Analyses of stomach content indicated a numerical prevalence of mites with an important proportion of oribatids-a group of arthropods known to contain one of the pumiliotoxins detected in E. iberia. This suggests that miniaturization and specialization to small prey may have favoured the acquisition of dietary skin alkaloids in these amphibians.

The first direct evidence of a Late Devonian coelacanth fish feeding on conodont animals

NASA Astrophysics Data System (ADS)

Zatoń, Michał; Broda, Krzysztof; Qvarnström, Martin; Niedźwiedzki, Grzegorz; Ahlberg, Per Erik

2017-04-01

We describe the first known occurrence of a Devonian coelacanth specimen from the lower Famennian of the Holy Cross Mountains, Poland, with a conodont element preserved in its digestive tract. A small spiral and phosphatic coprolite (fossil excrement) containing numerous conodont elements and other unrecognized remains was also found in the same deposits. The coprolite is tentatively attributed to the coelacanth. Although it is unclear whether the Late Devonian coelacanth from Poland was an active predator or a scavenger, these finds provide the first direct evidence of feeding on conodont animals by early coelacanth fish, and one of the few evidences of feeding on these animals known to date. It also expands our knowledge about the diet and trophic relations between the Paleozoic marine animals in general.

Speeding up GW Calculations to Meet the Challenge of Large Scale Quasiparticle Predictions.

PubMed

Gao, Weiwei; Xia, Weiyi; Gao, Xiang; Zhang, Peihong

2016-11-11

Although the GW approximation is recognized as one of the most accurate theories for predicting materials excited states properties, scaling up conventional GW calculations for large systems remains a major challenge. We present a powerful and simple-to-implement method that can drastically accelerate fully converged GW calculations for large systems, enabling fast and accurate quasiparticle calculations for complex materials systems. We demonstrate the performance of this new method by presenting the results for ZnO and MgO supercells. A speed-up factor of nearly two orders of magnitude is achieved for a system containing 256 atoms (1024 valence electrons) with a negligibly small numerical error of ±0.03 eV. Finally, we discuss the application of our method to the GW calculations for 2D materials.

Dynamics of periodic mechanical structures containing bistable elastic elements: From elastic to solitary wave propagation

NASA Astrophysics Data System (ADS)

Nadkarni, Neel; Daraio, Chiara; Kochmann, Dennis M.

2014-08-01

We investigate the nonlinear dynamics of a periodic chain of bistable elements consisting of masses connected by elastic springs whose constraint arrangement gives rise to a large-deformation snap-through instability. We show that the resulting negative-stiffness effect produces three different regimes of (linear and nonlinear) wave propagation in the periodic medium, depending on the wave amplitude. At small amplitudes, linear elastic waves experience dispersion that is controllable by the geometry and by the level of precompression. At moderate to large amplitudes, solitary waves arise in the weakly and strongly nonlinear regime. For each case, we present closed-form analytical solutions and we confirm our theoretical findings by specific numerical examples. The precompression reveals a class of wave propagation for a partially positive and negative potential. The presented results highlight opportunities in the design of mechanical metamaterials based on negative-stiffness elements, which go beyond current concepts primarily based on linear elastic wave propagation. Our findings shed light on the rich effective dynamics achievable by nonlinear small-scale instabilities in solids and structures.

On the determination of stress fields and displacements in a thin elastoplastic plate containing elastic inclusion - a shim

NASA Astrophysics Data System (ADS)

Kovalev, A. V.; Rusina, E. Y.; Yakovlev, A. Y.

2018-03-01

The paper is devoted to the determination of the stress-strain state of a mechanical structure, which consists of a thin infinite elastoplastic plate with a hole and a continuous fine elastic inclusion. The complexity of this problem lies in the fact that the shape of the boundary between the elastic and plastic zones in the plate is not known in advance. The small parameter method is used as the solution method, while the small parameter characterizes the deviation of the shape of the contour from the circle and the perturbation of external static boundary conditions. As the zero solution, the axisymmetric elastoplastic state of the plate with inclusion is chosen. Two variants of inclusion fixation in a plate are considered: inclusion is enclosed with tension or soldered. As a result of solving the problem within the framework of ideal plasticity, the distribution of the stress and displacement fields and the shape of the elastoplastic boundary are obtained. To illustrate the case of a plane-stressed state, the results of a numerical experiment on the mathematical model obtained are presented.

Theoretical studies in support of the 3M-vapor transport (PVTOS-) experiments

NASA Technical Reports Server (NTRS)

Rosner, Daniel E.; Keyes, David E.

1989-01-01

Results are reported for a preliminary theoretical study of the coupled mass-, momentum-, and heat-transfer conditions expected within small ampoules used to grow oriented organic solid (OS-) films, by physical vapor transport (PVT) in microgravity environments. It is show that previous studies made restrictive assumptions (e.g., smallness of delta T/T, equality of molecular diffusivities) not valid under PVTOS conditions, whereas the important phenomena of sidewall gas creep, Soret transport of the organic vapor, and large vapor phase supersaturations associated with the large prevailing temperature gradients were not previously considered. Rational estimates are made of the molecular transport properties relevant to copper-phthalocyanine monomeric vapor in a gas mixture containing H2(g) and Xe(g). Efficient numerical methods have been developed and are outlined/illustrated here to making steady axisymmetric gas flow calculations within such ampoules, allowing for realistic realistic delta T/T(sub)w-values, and even corrections to Navier-Stokes-Fourier 'closure' for the governing continuum differential equations. High priority follow-on studies are outlined based on these new results.

A "roller-wheel" Pt-containing small molecule that outperforms its polymer analogs in organic solar cells

DOE PAGES

He, Wenhan; Wu, Qin; Livshits, Maksim Y.; ...

2016-05-23

A novel Pt-bisacetylide small molecule (Pt-SM) featuring “roller-wheel” geometry was synthesized and characterized. When compared with conventional Pt-containing polymers and small molecules having “dumbbell” shaped structures, Pt-SM displays enhanced crystallinity and intermolecular π–π interactions, as well as favorable panchromatic absorption behaviors. Furthermore, organic solar cells (OSCs) employing Pt-SM achieve power conversion efficiencies (PCEs) up to 5.9%, the highest reported so far for Pt-containing polymers and small molecules.

A "roller-wheel" Pt-containing small molecule that outperforms its polymer analogs in organic solar cells

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

He, Wenhan; Wu, Qin; Livshits, Maksim Y.

A novel Pt-bisacetylide small molecule (Pt-SM) featuring “roller-wheel” geometry was synthesized and characterized. When compared with conventional Pt-containing polymers and small molecules having “dumbbell” shaped structures, Pt-SM displays enhanced crystallinity and intermolecular π–π interactions, as well as favorable panchromatic absorption behaviors. Furthermore, organic solar cells (OSCs) employing Pt-SM achieve power conversion efficiencies (PCEs) up to 5.9%, the highest reported so far for Pt-containing polymers and small molecules.

Computer Numerical Control: Instructional Manual. The North Dakota High Technology Mobile Laboratory Project.

ERIC Educational Resources Information Center

Sinn, John W.

This instructional manual contains five learning activity packets for use in a workshop on computer numerical control for computer-aided manufacturing. The lessons cover the following topics: introduction to computer-aided manufacturing, understanding the lathe, using the computer, computer numerically controlled part programming, and executing a…

Water-Rock Differentiation of Icy Bodies by Darcy law, Stokes law, and Two-Phase Flow

NASA Astrophysics Data System (ADS)

Neumann, Wladimir; Breuer, Doris; Spohn, Tilman

2016-10-01

The early Solar system produced a variety of bodies with different properties. Among the small bodies, objects that contain notable amounts of water ice are of particular interest. Water-rock separation on such worlds is probable and has been confirmed in some cases. We couple accretion and water-rock separation in a numerical model. The model is applicable to Ceres, icy satellites, and Kuiper belt objects, and is suited to assess the thermal metamorphism of the interior and the present-day internal structures. The relative amount of ice determines the differentiation regime according to porous flow or Stokes flow. Porous flow considers differentiation in a rock matrix with a small degree of ice melting and is typically modelled either with the Darcy law or two-phase flow. We find that for small icy bodies two-phase flow differs from the Darcy law. Velocities derived from two-phase flow are at least one order of magnitude smaller than Darcy velocities. The latter do not account for the matrix resistance against the deformation and overestimate the separation velocity. In the Stokes regime that should be used for large ice fractions, differentiation is at least four orders of magnitude faster than porous flow with the parameters used here.

36 CFR 216.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... consists of numerous volumes organized by numerically coded subject matter. The volumes contain legal... jurisdiction for which they are issued. The Forest Service Manual is revised to conform to changing law, orders...

36 CFR 216.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... consists of numerous volumes organized by numerically coded subject matter. The volumes contain legal... jurisdiction for which they are issued. The Forest Service Manual is revised to conform to changing law, orders...

Gated Silica Mesoporous Materials in Sensing Applications.

PubMed

Sancenón, Félix; Pascual, Lluís; Oroval, Mar; Aznar, Elena; Martínez-Máñez, Ramón

2015-08-01

Silica mesoporous supports (SMSs) have a large specific surface area and volume and are particularly exciting vehicles for delivery applications. Such container-like structures can be loaded with numerous different chemical substances, such as drugs and reporters. Gated systems also contain addressable functions at openings of voids, and cargo delivery can be controlled on-command using chemical, biochemical or physical stimuli. Many of these gated SMSs have been applied for drug delivery. However, fewer examples of their use in sensing protocols have been reported. The approach of applying SMSs in sensing uses another concept-that of loading pores with a reporter and designing a capping mechanism that is selectively opened in the presence of a target analyte, which results in the delivery of the reporter. According to this concept, we provide herein a complete compilation of published examples of probes based on the use of capped SMSs for sensing. Examples for the detection of anions, cations, small molecules and biomolecules are provided. The diverse range of gated silica mesoporous materials presented here highlights their usefulness in recognition protocols.

Cancer cells copy migratory behavior and exchange signaling networks via extracellular vesicles.

PubMed

Steenbeek, Sander C; Pham, Thang V; de Ligt, Joep; Zomer, Anoek; Knol, Jaco C; Piersma, Sander R; Schelfhorst, Tim; Huisjes, Rick; Schiffelers, Raymond M; Cuppen, Edwin; Jimenez, Connie R; van Rheenen, Jacco

2018-06-14

Recent data showed that cancer cells from different tumor subtypes with distinct metastatic potential influence each other's metastatic behavior by exchanging biomolecules through extracellular vesicles (EVs). However, it is debated how small amounts of cargo can mediate this effect, especially in tumors where all cells are from one subtype, and only subtle molecular differences drive metastatic heterogeneity. To study this, we have characterized the content of EVs shed in vivo by two clones of melanoma (B16) tumors with distinct metastatic potential. Using the Cre-LoxP system and intravital microscopy, we show that cells from these distinct clones phenocopy their migratory behavior through EV exchange. By tandem mass spectrometry and RNA sequencing, we show that EVs shed by these clones into the tumor microenvironment contain thousands of different proteins and RNAs, and many of these biomolecules are from interconnected signaling networks involved in cellular processes such as migration. Thus, EVs contain numerous proteins and RNAs and act on recipient cells by invoking a multi-faceted biological response including cell migration. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

Gated Silica Mesoporous Materials in Sensing Applications

PubMed Central

Sancenón, Félix; Pascual, Lluís; Oroval, Mar; Aznar, Elena; Martínez-Máñez, Ramón

2015-01-01

Silica mesoporous supports (SMSs) have a large specific surface area and volume and are particularly exciting vehicles for delivery applications. Such container-like structures can be loaded with numerous different chemical substances, such as drugs and reporters. Gated systems also contain addressable functions at openings of voids, and cargo delivery can be controlled on-command using chemical, biochemical or physical stimuli. Many of these gated SMSs have been applied for drug delivery. However, fewer examples of their use in sensing protocols have been reported. The approach of applying SMSs in sensing uses another concept—that of loading pores with a reporter and designing a capping mechanism that is selectively opened in the presence of a target analyte, which results in the delivery of the reporter. According to this concept, we provide herein a complete compilation of published examples of probes based on the use of capped SMSs for sensing. Examples for the detection of anions, cations, small molecules and biomolecules are provided. The diverse range of gated silica mesoporous materials presented here highlights their usefulness in recognition protocols. PMID:26491626

Vitrinite reflectance of sinkhole coals, east central Missouri fire clay district

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

Laudon, R.C.

1993-03-01

East central Missouri contains numerous sinkholes many of which are filled with commercial quantities of fire clay and some contain small amounts of coal. Vitrinite reflectance averages from 513 samples taken from eleven of these coals ranged from 0.71 to 0.78. Data were remarkably consistent and no local trends were observed. Using Barker and Goldstein (1990) and Barker and Pawlewicz (1986) temperature correlations, these measurements suggest that the coals have been heated to temperatures on the order of 108 C to 128 C (average = 116). These temperatures are considered anomalously high when compared against known geothermal gradients and burialmore » depths for these rocks. The temperatures suggest that the sinkhole coals have been heated by some thermal event, possibly associated with Mississippi Valley type mineralization. These temperatures are consistent with regional trends in the state. This data, when combined with other vitrinite reflectance and fluid inclusion data (right), suggest that southwest Missouri (Tristate) and southeast Missouri (Viburnum Trend) were hot spots, and that temperatures decrease regionally away from these two areas.« less

CLE signaling systems during plant development and nematode infection.

PubMed

Kiyohara, Syunsuke; Sawa, Shinichiro

2012-12-01

Plants contain numerous CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (ESR) (CLE) genes encoding small secreted peptide hormones that function in a variety of developmental and physiological processes. The first known Arabidopsis CLE gene was originally discovered through the analysis of clv3 mutants, which exhibit fasciated stems and an increased number of floral organs. In total, 32 CLE genes have been identified in Arabidopsis. Amongst these are CLV3 and CLE40, which repress the expression of homeobox-containing genes WUSCHEL (WUS) and WUSCHEL-related homeobox 5 (WOX5) to control shoot apical meristem (SAM) and root columella initial cell activity, respectively. Interestingly, the CLE signaling pathway appears to be conserved amongst plants. In this review, we discuss the latest research uncovering the diverse functions and activities of CLE peptides in plants; especially during shoot, root and vascular development. In addition, we discuss the important role of CLE peptides during infection by phytoparasitic nematodes. Understanding the molecular properties of CLE peptides and their modes of action will provide further insight into plant cell-cell communication, which could also be applied to manipulate plant-nematode interactions.

Small-Sided Games: Developmentally Appropriate Applications in Traditional Activities.

ERIC Educational Resources Information Center

Petersen, Susan; Cruz, Luz

This paper presents a systematic progression of small-sided games within two traditional sports units (soccer and volleyball). Developmentally appropriate guidelines encourage teachers at all levels to incorporate small-sided games (2v2, 3v3, and 4v4). Advantages of small-sided games include: allowing students numerous practice opportunities;…

12 CFR 345.42 - Data collection, reporting, and disclosure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... calendar year: (1) Small business and small farm loan data. For each geography in which the bank originated... by the FDIC) until the completion of its next CRA examination, the following data for each small business or small farm loan originated or purchased by the bank: (1) A unique number or alpha-numeric...

12 CFR 228.42 - Data collection, reporting, and disclosure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... calendar year: (1) Small business and small farm loan data. For each geography in which the bank originated... prescribed by the Board) until the completion of its next CRA examination, the following data for each small business or small farm loan originated or purchased by the bank: (1) A unique number or alpha-numeric...

12 CFR 25.42 - Data collection, reporting, and disclosure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... year: (1) Small business and small farm loan data. For each geography in which the bank originated or... prescribed by the OCC) until the completion of its next CRA examination, the following data for each small business or small farm loan originated or purchased by the bank: (1) A unique number or alpha-numeric...

12 CFR 228.42 - Data collection, reporting, and disclosure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... calendar year: (1) Small business and small farm loan data. For each geography in which the bank originated... prescribed by the Board) until the completion of its next CRA examination, the following data for each small business or small farm loan originated or purchased by the bank: (1) A unique number or alpha-numeric...

12 CFR 25.42 - Data collection, reporting, and disclosure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... year: (1) Small business and small farm loan data. For each geography in which the bank originated or... prescribed by the OCC) until the completion of its next CRA examination, the following data for each small business or small farm loan originated or purchased by the bank: (1) A unique number or alpha-numeric...

12 CFR 25.42 - Data collection, reporting, and disclosure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... year: (1) Small business and small farm loan data. For each geography in which the bank originated or... prescribed by the OCC) until the completion of its next CRA examination, the following data for each small business or small farm loan originated or purchased by the bank: (1) A unique number or alpha-numeric...

12 CFR 25.42 - Data collection, reporting, and disclosure.

Code of Federal Regulations, 2011 CFR

2011-01-01

... year: (1) Small business and small farm loan data. For each geography in which the bank originated or... prescribed by the OCC) until the completion of its next CRA examination, the following data for each small business or small farm loan originated or purchased by the bank: (1) A unique number or alpha-numeric...

12 CFR 345.42 - Data collection, reporting, and disclosure.

Code of Federal Regulations, 2012 CFR

2012-01-01

... calendar year: (1) Small business and small farm loan data. For each geography in which the bank originated... by the FDIC) until the completion of its next CRA examination, the following data for each small business or small farm loan originated or purchased by the bank: (1) A unique number or alpha-numeric...

12 CFR 345.42 - Data collection, reporting, and disclosure.

Code of Federal Regulations, 2013 CFR

2013-01-01

... calendar year: (1) Small business and small farm loan data. For each geography in which the bank originated... by the FDIC) until the completion of its next CRA examination, the following data for each small business or small farm loan originated or purchased by the bank: (1) A unique number or alpha-numeric...

12 CFR 345.42 - Data collection, reporting, and disclosure.

Code of Federal Regulations, 2014 CFR

2014-01-01

... calendar year: (1) Small business and small farm loan data. For each geography in which the bank originated... by the FDIC) until the completion of its next CRA examination, the following data for each small business or small farm loan originated or purchased by the bank: (1) A unique number or alpha-numeric...

DrugBank: a knowledgebase for drugs, drug actions and drug targets

PubMed Central

Wishart, David S.; Knox, Craig; Guo, An Chi; Cheng, Dean; Shrivastava, Savita; Tzur, Dan; Gautam, Bijaya; Hassanali, Murtaza

2008-01-01

DrugBank is a richly annotated resource that combines detailed drug data with comprehensive drug target and drug action information. Since its first release in 2006, DrugBank has been widely used to facilitate in silico drug target discovery, drug design, drug docking or screening, drug metabolism prediction, drug interaction prediction and general pharmaceutical education. The latest version of DrugBank (release 2.0) has been expanded significantly over the previous release. With ∼4900 drug entries, it now contains 60% more FDA-approved small molecule and biotech drugs including 10% more ‘experimental’ drugs. Significantly, more protein target data has also been added to the database, with the latest version of DrugBank containing three times as many non-redundant protein or drug target sequences as before (1565 versus 524). Each DrugCard entry now contains more than 100 data fields with half of the information being devoted to drug/chemical data and the other half devoted to pharmacological, pharmacogenomic and molecular biological data. A number of new data fields, including food–drug interactions, drug–drug interactions and experimental ADME data have been added in response to numerous user requests. DrugBank has also significantly improved the power and simplicity of its structure query and text query searches. DrugBank is available at http://www.drugbank.ca PMID:18048412

DNA sequencing using fluorescence background electroblotting membrane

DOEpatents

Caldwell, Karin D.; Chu, Tun-Jen; Pitt, William G.

1992-01-01

A method for the multiplex sequencing on DNA is disclosed which comprises the electroblotting or specific base terminated DNA fragments, which have been resolved by gel electrophoresis, onto the surface of a neutral non-aromatic polymeric microporous membrane exhibiting low background fluorescence which has been surface modified to contain amino groups. Polypropylene membranes are preferably and the introduction of amino groups is accomplished by subjecting the membrane to radio or microwave frequency plasma discharge in the presence of an aminating agent, preferably ammonia. The membrane, containing physically adsorbed DNA fragments on its surface after the electroblotting, is then treated with crosslinking means such as UV radiation or a glutaraldehyde spray to chemically bind the DNA fragments to the membrane through said smino groups contained on the surface thereof. The DNA fragments chemically bound to the membrane are subjected to hybridization probing with a tagged probe specific to the sequence of the DNA fragments. The tagging may be by either fluorophores or radioisotopes. The tagged probes hybridized to said target DNA fragments are detected and read by laser induced fluorescence detection or autoradiograms. The use of aminated low fluorescent background membranes allows the use of fluorescent detection and reading even when the available amount of DNA to be sequenced is small. The DNA bound to the membrances may be reprobed numerous times.

DNA sequencing using fluorescence background electroblotting membrane

DOEpatents

Caldwell, K.D.; Chu, T.J.; Pitt, W.G.

1992-05-12

A method for the multiplex sequencing on DNA is disclosed which comprises the electroblotting or specific base terminated DNA fragments, which have been resolved by gel electrophoresis, onto the surface of a neutral non-aromatic polymeric microporous membrane exhibiting low background fluorescence which has been surface modified to contain amino groups. Polypropylene membranes are preferably and the introduction of amino groups is accomplished by subjecting the membrane to radio or microwave frequency plasma discharge in the presence of an aminating agent, preferably ammonia. The membrane, containing physically adsorbed DNA fragments on its surface after the electroblotting, is then treated with crosslinking means such as UV radiation or a glutaraldehyde spray to chemically bind the DNA fragments to the membrane through amino groups contained on the surface. The DNA fragments chemically bound to the membrane are subjected to hybridization probing with a tagged probe specific to the sequence of the DNA fragments. The tagging may be by either fluorophores or radioisotopes. The tagged probes hybridized to the target DNA fragments are detected and read by laser induced fluorescence detection or autoradiograms. The use of aminated low fluorescent background membranes allows the use of fluorescent detection and reading even when the available amount of DNA to be sequenced is small. The DNA bound to the membranes may be reprobed numerous times. No Drawings

Personal computer study of finite-difference methods for the transonic small disturbance equation

NASA Technical Reports Server (NTRS)

Bland, Samuel R.

1989-01-01

Calculation of unsteady flow phenomena requires careful attention to the numerical treatment of the governing partial differential equations. The personal computer provides a convenient and useful tool for the development of meshes, algorithms, and boundary conditions needed to provide time accurate solution of these equations. The one-dimensional equation considered provides a suitable model for the study of wave propagation in the equations of transonic small disturbance potential flow. Numerical results for effects of mesh size, extent, and stretching, time step size, and choice of far-field boundary conditions are presented. Analysis of the discretized model problem supports these numerical results. Guidelines for suitable mesh and time step choices are given.

Numerical simulation of small-scale thermal convection in the atmosphere

NASA Technical Reports Server (NTRS)

Somerville, R. C. J.

1973-01-01

A Boussinesq system is integrated numerically in three dimensions and time in a study of nonhydrostatic convection in the atmosphere. Simulation of cloud convection is achieved by the inclusion of parametrized effects of latent heat and small-scale turbulence. The results are compared with the cell structure observed in Rayleigh-Benard laboratory conversion experiments in air. At a Rayleigh number of 4000, the numerical model adequately simulates the experimentally observed evolution, including some prominent transients of a flow from a randomly perturbed initial conductive state into the final state of steady large-amplitude two-dimensional rolls. At Rayleigh number 9000, the model reproduces the experimentally observed unsteady equilibrium of vertically coherent oscillatory waves superimposed on rolls.

Standardized Curriculum for Small Engine Repair.

ERIC Educational Resources Information Center

Mississippi State Dept. of Education, Jackson. Office of Vocational, Technical and Adult Education.

This curriculum guide for small engine repair was developed by the state of Mississippi to standardize vocational education course titles and core contents. The objectives contained in this document are common to all small engine repair programs in the state. The guide contains objectives for small engine repair I and II courses. Units in course I…

Study on propellant dynamics during docking

NASA Technical Reports Server (NTRS)

Feng, G. C.; Robertson, S. J.

1972-01-01

The marker-and-cell numerical technique was applied to the study of axisymmetric and two-dimensional flow of liquid in containers under low gravity conditions. The purpose of the study was to provide the capability for numerically simulating liquid propellant motion in partially filled containers during a docking maneuver in orbit. A computer program to provide this capability for axisymmetric and two-dimensional flow was completed and computations were made for a number of hypothetical flow conditions.

Monitoring bird populations in small geographic areas

USGS Publications Warehouse

Dunn, Erica H.; Bart, J.; Collins, B.T.; Craig, B.; Dale, B.; Downes, C.M.; Francis, C.M.; Woodley, S.; Zorn, P.

2006-01-01

Numerous methods exist for monitoring bird populations, and there is a large literature describing them. There are few resources, however, that provide comprehensive advice on every step of organizing and carrying out a survey, from the early stages of planning to final use of the data. Even fewer resources are designed to meet the needs of a wide variety of potential users, from amateurs interested in change of bird life in a local study preserve to professionals testing hypotheses on the response of birds to habitat management, although much of the advice should be the same for every monitoring program. Whether survey objectives are very modest or rigorously scientific, samples must be sufficiently numerous and well distributed to provide meaningful results, and the survey should be well designed to ensure that the money and effort going into it are not wasted. This document is intended to be a complete resource for anyone planning to organize monitoring of noncolonial landbirds within a relatively small geographic area (e.g., from the size of a woodlot to a large park). The first of its two parts provides background explaining the importance of good study design and gives specific advice on all aspects of project planning and execution of high-quality data collection for the purpose of hypothesis testing. The second part is self-contained and nontechnical and describes complete plans for a site-specific checklist survey, suitable for addressing monitoring questions frequently asked by amateurs and for involvement of volunteers in data collection. Throughout are references to additional resources, from background literature to sources of existing survey protocols, analysis software, and tools for archiving data.

Numerical simulation of pressure fluctuation in 1000MW Francis turbine under small opening condition

NASA Astrophysics Data System (ADS)

Gong, R. Z.; Wang, H. G.; Yao, Y.; Shu, L. F.; Huang, Y. J.

2012-11-01

In order to study the cause of abnormal vibration in large Francis turbine under small opening condition, CFD method was adopted to analyze the flow filed and pressure fluctuation. Numerical simulation was performed on the commercial CFD code Ansys FLUENT 12, using DES method. After an effective validation of the computation result, the flow behaviour of internal flow field under small opening condition is analyzed. Pressure fluctuation in different working mode is obtained by unsteady CFD simulation, and results is compared to study its change. Radial force fluctuation is also analyzed. The result shows that the unstable flow under small opening condition leads to an increase of turbine instability in reverse pump mode, and is one possible reason of the abnormal oscillation.

Beer tapping: dynamics of bubbles after impact

NASA Astrophysics Data System (ADS)

Mantič-Lugo, V.; Cayron, A.; Brun, P.-T.; Gallaire, F.

2015-12-01

Beer tapping is a well known prank where a bottle of beer is impacted from the top by a solid object, usually another bottle, leading to a sudden foam overflow. A description of the shock-driven bubble dynamics leading to foaming is presented based on an experimental and numerical study evoking the following physical picture. First, the solid impact produces a sudden downwards acceleration of the bottle creating a strong depression in the liquid bulk. The existing bubbles undergo a strong expansion and a sudden contraction ending in their collapse and fragmentation into a large amount of small bubbles. Second, the bubble clouds present a large surface area to volume ratio, enhancing the CO2 diffusion from the supersaturated liquid, hence growing rapidly and depleting the CO2. The clouds of bubbles migrate upwards in the form of plumes pulling the surrounding liquid with them and eventually resulting in the foam overflow. The sudden pressure drop that triggers the bubble dynamics with a collapse and oscillations is modelled by the Rayleigh-Plesset equation. The bubble dynamics from impact to collapse occurs over a time (tb ≃ 800 μs) much larger than the acoustic time scale of the liquid bulk (tac = 2H/c ≃ 80 μs), for the experimental container of height H = 6 cm and a speed of sound around c ≃ 1500 m/s. This scale separation, together with the comparison of numerical and experimental results, suggests that the pressure drop is controlled by two parameters: the acceleration of the container and the distance from the bubble to the free surface.

Construction of Low Dissipative High Order Well-Balanced Filter Schemes for Non-Equilibrium Flows

NASA Technical Reports Server (NTRS)

Wang, Wei; Yee, H. C.; Sjogreen, Bjorn; Magin, Thierry; Shu, Chi-Wang

2009-01-01

The goal of this paper is to generalize the well-balanced approach for non-equilibrium flow studied by Wang et al. [26] to a class of low dissipative high order shock-capturing filter schemes and to explore more advantages of well-balanced schemes in reacting flows. The class of filter schemes developed by Yee et al. [30], Sjoegreen & Yee [24] and Yee & Sjoegreen [35] consist of two steps, a full time step of spatially high order non-dissipative base scheme and an adaptive nonlinear filter containing shock-capturing dissipation. A good property of the filter scheme is that the base scheme and the filter are stand alone modules in designing. Therefore, the idea of designing a well-balanced filter scheme is straightforward, i.e., choosing a well-balanced base scheme with a well-balanced filter (both with high order). A typical class of these schemes shown in this paper is the high order central difference schemes/predictor-corrector (PC) schemes with a high order well-balanced WENO filter. The new filter scheme with the well-balanced property will gather the features of both filter methods and well-balanced properties: it can preserve certain steady state solutions exactly; it is able to capture small perturbations, e.g., turbulence fluctuations; it adaptively controls numerical dissipation. Thus it shows high accuracy, efficiency and stability in shock/turbulence interactions. Numerical examples containing 1D and 2D smooth problems, 1D stationary contact discontinuity problem and 1D turbulence/shock interactions are included to verify the improved accuracy, in addition to the well-balanced behavior.

Application of boundary element method to Stokes flows over a striped superhydrophobic surface with trapped gas bubbles

NASA Astrophysics Data System (ADS)

Ageev, A. I.; Golubkina, I. V.; Osiptsov, A. N.

2018-01-01

A slow steady flow of a viscous fluid over a superhydrophobic surface with a periodic striped system of 2D rectangular microcavities is considered. The microcavities contain small gas bubbles on the curved surface of which the shear stress vanishes. The general case is analyzed when the bubble occupies only a part of the cavity, and the flow velocity far from the surface is directed at an arbitrary angle to the cavity edge. Due to the linearity of the Stokes flow problem, the solution is split into two parts, corresponding to the flows perpendicular and along the cavities. Two variants of a boundary element method are developed and used to construct numerical solutions on the scale of a single cavity with periodic boundary conditions. By averaging these solutions, the average slip velocity and the slip length tensor components are calculated over a wide range of variation of governing parameters for the cases of a shear-driven flow and a pressure-driven channel flow. For a sufficiently high pressure drop in a microchannel of finite length, the variation of the bubble surface shift into the cavities induced by the streamwise pressure variation is estimated from numerical calculations.

Radioactive Phosphorylation of Alcohols to Monitor Biocatalytic Diels-Alder Reactions

PubMed Central

Nierth, Alexander; Jäschke, Andres

2011-01-01

Nature has efficiently adopted phosphorylation for numerous biological key processes, spanning from cell signaling to energy storage and transmission. For the bioorganic chemist the number of possible ways to attach a single phosphate for radioactive labeling is surprisingly small. Here we describe a very simple and fast one-pot synthesis to phosphorylate an alcohol with phosphoric acid using trichloroacetonitrile as activating agent. Using this procedure, we efficiently attached the radioactive phosphorus isotope 32P to an anthracene diene, which is a substrate for the Diels-Alderase ribozyme—an RNA sequence that catalyzes the eponymous reaction. We used the 32P-substrate for the measurement of RNA-catalyzed reaction kinetics of several dye-labeled ribozyme variants for which precise optical activity determination (UV/vis, fluorescence) failed due to interference of the attached dyes. The reaction kinetics were analyzed by thin-layer chromatographic separation of the 32P-labeled reaction components and densitometric analysis of the substrate and product radioactivities, thereby allowing iterative optimization of the dye positions for future single-molecule studies. The phosphorylation strategy with trichloroacetonitrile may be applicable for labeling numerous other compounds that contain alcoholic hydroxyl groups. PMID:21731729

75 FR 36743 - Self-Regulatory Organizations; Chicago Stock Exchange, Inc.; Notice of Filing of Proposed Rule...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-28

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75 FR 36746 - Self-Regulatory Organizations; National Stock Exchange, Inc.; Notice of Filing of Proposed Rule...

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48 CFR 1816.405-275 - Award fee evaluation rating.

Code of Federal Regulations, 2012 CFR

2012-10-01

... each adjectival rating category contained in FAR 16.401(e)(iv). (b) The following numerical scoring...). The numerical score for each factor is then multiplied by the weighting for that factor to determine... numerical score for that factor is 80, the weighted technical score is 48 (80 × 60 percent). The weighted...

48 CFR 1816.405-275 - Award fee evaluation rating.

Code of Federal Regulations, 2011 CFR

2011-10-01

... each adjectival rating category contained in FAR 16.401(e)(iv). (b) The following numerical scoring...). The numerical score for each factor is then multiplied by the weighting for that factor to determine... numerical score for that factor is 80, the weighted technical score is 48 (80 × 60 percent). The weighted...

48 CFR 1816.405-275 - Award fee evaluation rating.

Code of Federal Regulations, 2014 CFR

2014-10-01

... each adjectival rating category contained in FAR 16.401(e)(iv). (b) The following numerical scoring...). The numerical score for each factor is then multiplied by the weighting for that factor to determine... numerical score for that factor is 80, the weighted technical score is 48 (80 × 60 percent). The weighted...

48 CFR 1816.405-275 - Award fee evaluation rating.

Code of Federal Regulations, 2013 CFR

2013-10-01

... each adjectival rating category contained in FAR 16.401(e)(iv). (b) The following numerical scoring...). The numerical score for each factor is then multiplied by the weighting for that factor to determine... numerical score for that factor is 80, the weighted technical score is 48 (80 × 60 percent). The weighted...

The Power of 2: How an Apparently Irregular Numeration System Facilitates Mental Arithmetic

ERIC Educational Resources Information Center

Bender, Andrea; Beller, Sieghard

2017-01-01

Mangarevan traditionally contained two numeration systems: a general one, which was highly regular, decimal, and extraordinarily extensive; and a specific one, which was restricted to specific objects, based on diverging counting units, and interspersed with binary steps. While most of these characteristics are shared by numeration systems in…

You can count on the motor cortex: finger counting habits modulate motor cortex activation evoked by numbers.

PubMed

Tschentscher, Nadja; Hauk, Olaf; Fischer, Martin H; Pulvermüller, Friedemann

2012-02-15

The embodied cognition framework suggests that neural systems for perception and action are engaged during higher cognitive processes. In an event-related fMRI study, we tested this claim for the abstract domain of numerical symbol processing: is the human cortical motor system part of the representation of numbers, and is organization of numerical knowledge influenced by individual finger counting habits? Developmental studies suggest a link between numerals and finger counting habits due to the acquisition of numerical skills through finger counting in childhood. In the present study, digits 1 to 9 and the corresponding number words were presented visually to adults with different finger counting habits, i.e. left- and right-starters who reported that they usually start counting small numbers with their left and right hand, respectively. Despite the absence of overt hand movements, the hemisphere contralateral to the hand used for counting small numbers was activated when small numbers were presented. The correspondence between finger counting habits and hemispheric motor activation is consistent with an intrinsic functional link between finger counting and number processing. Copyright © 2011 Elsevier Inc. All rights reserved.

Spinning solutions in general relativity with infinite central density

NASA Astrophysics Data System (ADS)

Flammer, P. D.

2018-05-01

This paper presents general relativistic numerical simulations of uniformly rotating polytropes. Equations are developed using MSQI coordinates, but taking a logarithm of the radial coordinate. The result is relatively simple elliptical differential equations. Due to the logarithmic scale, we can resolve solutions with near-singular mass distributions near their center, while the solution domain extends many orders of magnitude larger than the radius of the distribution (to connect with flat space-time). Rotating solutions are found with very high central energy densities for a range of adiabatic exponents. Analytically, assuming the pressure is proportional to the energy density (which is true for polytropes in the limit of large energy density), we determine the small radius behavior of the metric potentials and energy density. This small radius behavior agrees well with the small radius behavior of large central density numerical results, lending confidence to our numerical approach. We compare results with rotating solutions available in the literature, which show good agreement. We study the stability of spherical solutions: instability sets in at the first maximum in mass versus central energy density; this is also consistent with results in the literature, and further lends confidence to the numerical approach.

Numerical analysis of the angular motion of a neutrally buoyant spheroid in shear flow at small Reynolds numbers.

PubMed

Rosén, T; Einarsson, J; Nordmark, A; Aidun, C K; Lundell, F; Mehlig, B

2015-12-01

We numerically analyze the rotation of a neutrally buoyant spheroid in a shear flow at small shear Reynolds number. Using direct numerical stability analysis of the coupled nonlinear particle-flow problem, we compute the linear stability of the log-rolling orbit at small shear Reynolds number Re(a). As Re(a)→0 and as the box size of the system tends to infinity, we find good agreement between the numerical results and earlier analytical predictions valid to linear order in Re(a) for the case of an unbounded shear. The numerical stability analysis indicates that there are substantial finite-size corrections to the analytical results obtained for the unbounded system. We also compare the analytical results to results of lattice Boltzmann simulations to analyze the stability of the tumbling orbit at shear Reynolds numbers of order unity. Theory for an unbounded system at infinitesimal shear Reynolds number predicts a bifurcation of the tumbling orbit at aspect ratio λ(c)≈0.137 below which tumbling is stable (as well as log rolling). The simulation results show a bifurcation line in the λ-Re(a) plane that reaches λ≈0.1275 at the smallest shear Reynolds number (Re(a)=1) at which we could simulate with the lattice Boltzmann code, in qualitative agreement with the analytical results.

Integrated Assessment to Evaluate the Artificial Recharge in a Small Portion of the Aquifer of Puebla, Mexico

NASA Astrophysics Data System (ADS)

Arango-Galván, C.; Flores-Marquez, L. E.; Martínez-Serrano, R.

2009-12-01

New policies on the use of water resources in Mexico have led to implement some alternative measures to optimize water management. In particular, water regulation entities have recommended some tools to preserve and protect the groundwater supplies. One of these tools is the artificial recharge by injecting water directly into the aquifer. The main goal of this study is to assess if it is suitable to inject rainwater and surface water in a small portion of the aquifer of the city of Puebla, in central Mexico. Artificial aquifer recharging was evaluated using a numeric model, which simulated the physical properties of the system. The model setup was inferred from an integrated study taking into account hydraulic, geological and geophysical data. The geoelectrical model was computed using electric resistivity tomography (ERT) and time domain electromagnetic data (TDEM). The aquifer geological structure inferred from geophysics depicts the presence of a shallower layer composed of sand and clay deposits with low saturation and permeability. This layer contains silt lenses that can be controlling the persistence of small water bodies on surface. Some water surficial bodies seem to be isolated from the main aquifer system. The intermediate layer shows lower electrical resistivity and higher permeability. Underlying this horizon, it is a deeper layer that reaches 200 m depth, according to information obtained from borehole in the zone. This layer shows an electrical resistivity even lower than intermediate layer but low permeability, caused by the higher content of silts. Both of these layers are the shallower aquifer exploited in the area. Once the numeric model was built we proceeded to simulate scenarios that include the continued extraction and recharge of water in wells located in strategic areas of the study zone. The results suggest that the effect of infiltration is beneficial on aquifer recharge and reduces the cone of depression caused by the extraction. However, this remedial action will only have a positive effect if the extraction rate is adequate.

The deep muscular plexus of the pig duodenum: a histochemical and ultrastructural study with special reference to the interstitial cells.

PubMed

Henry, M; Porcher, C; Julé, Y

1998-06-10

The aim of the present study was to describe the deep muscular plexus of the pig duodenum and to characterize its cellular components. Numerous nerve varicosities have been detected in the deep muscular plexus using anti-synaptophysin antibodies. Nerve fibres were also detected here in the outer circular muscle layer, whereas no nerve fibres were observed in the inner circular muscle layer. In the deep muscular plexus, nerve fibres projected to interstitial cells which were characterized at the ultrastructural level. The interstitial cells were of two kinds: the interstitial fibroblastic-like cells (FLC) and the interstitial dense cells (IDC), both of which were interposed between nerve fibres and smooth muscle cells. The FLC were characterized by their elongated bipolar shape, the lack of basal lamina, a well-developed endoplasmic reticulum, a Golgi apparatus, and intermediate filaments. They were closely apposed to axon terminals containing small clear synaptic vesicles and/or dense-cored vesicles. They were frequently connected to each other and to smooth muscle cells of the inner and outer circular layer by desmosomes and more rarely by gap junctions. The IDC are myoid-like cells. They had a stellate appearance and were characterized by a dense cell body, numerous caveolae, and a discontinuous basal lamina. The IDC were always closely apposed to nerve fibres and were connected to smooth muscle cells by desmosomes and small gap junctions. The present results show the unique pattern of cellular organization of the deep muscular plexus of the pig small intestine. They suggest that the interstitial cells in the deep muscular plexus are involved in the integration and transmission of nervous inputs from myenteric neurons to the inner and outer circular muscle layers. The clear-cut distinction observed here between the two types of interstitial cells (fibroblastic and myoid-like) suggests that the interstitial cells of each type may also be involved in some other specific activity, which still remains to be determined.

Small mammals of the Bitterroot National Forest: Ecological significance and guidelines for management

Treesearch

Dean E. Pearson

2000-01-01

Small mammal literature was reviewed to assess the ecological role of small mammals on the Bitterroot National Forest of western Montana. Small mammals fulfill numerous important roles in forest ecosystems by supporting a wide range of predators, dispersing seeds and mycorrhizal spores, altering vegetation through herbivory and seed predation, and preying on insects....

General Relativistic Precession in Small Solar System Bodies

NASA Astrophysics Data System (ADS)

Sekhar, Aswin; Werner, Stephanie; Hoffmann, Volker; Asher, David; Vaubaillon, Jeremie; Hajdukova, Maria; Li, Gongjie

2016-10-01

Introduction: One of the greatest successes of the Einstein's General Theory of Relativity (GR) was the correct prediction of the precession of perihelion of Mercury. The closed form expression to compute this precession tells us that substantial GR precession would occur only if the bodies have a combination of both moderately small perihelion distance and semi-major axis. Minimum Orbit Intersection Distance (MOID) is a quantity which helps us to understand the closest proximity of two orbits in space. Hence evaluating MOID is crucial to understand close encounters and collision scenarios better. In this work, we look at the possible scenarios where a small GR precession in argument of pericentre (ω) can create substantial changes in MOID for small bodies ranging from meteoroids to comets and asteroids.Analytical Approach and Numerical Integrations: Previous works have looked into neat analytical techniques to understand different collision scenarios and we use those standard expressions to compute MOID analytically. We find the nature of this mathematical function is such that a relatively small GR precession can lead to drastic changes in MOID values depending on the initial value of ω. Numerical integrations were done with package MERCURY incorporating the GR code to test the same effects. Numerical approach showed the same interesting relationship (as shown by analytical theory) between values of ω and the peaks/dips in MOID values. Previous works have shown that GR precession suppresses Kozai oscillations and this aspect was verified using our integrations. There is an overall agreement between both analytical and numerical methods.Summary and Discussion: We find that GR precession could play an important role in the calculations pertaining to MOID and close encounter scenarios in the case of certain small solar system bodies (depending on their initial orbital elements). Previous works have looked into impact probabilities and collision scenarios on planets from different small body populations. This work aims to find certain sub-sets of orbits where GR could play an interesting role. Certain parallels are drawn between the cases of asteroids, comets and small perihelion distance meteoroid streams.

How number line estimation skills relate to neural activations in single digit subtraction problems

PubMed Central

Berteletti, I.; Man, G.; Booth, J.R.

2014-01-01

The Number Line (NL) task requires judging the relative numerical magnitude of a number and estimating its value spatially on a continuous line. Children's skill on this task has been shown to correlate with and predict future mathematical competence. Neurofunctionally, this task has been shown to rely on brain regions involved in numerical processing. However, there is no direct evidence that performance on the NL task is related to brain areas recruited during arithmetical processing and that these areas are domain-specific to numerical processing. In this study, we test whether 8- to 14-year-old's behavioral performance on the NL task is related to fMRI activation during small and large single-digit subtraction problems. Domain-specific areas for numerical processing were independently localized through a numerosity judgment task. Results show a direct relation between NL estimation performance and the amount of the activation in key areas for arithmetical processing. Better NL estimators showed a larger problem size effect than poorer NL estimators in numerical magnitude (i.e., intraparietal sulcus) and visuospatial areas (i.e., posterior superior parietal lobules), marked by less activation for small problems. In addition, the direction of the activation with problem size within the IPS was associated to differences in accuracies for small subtraction problems. This study is the first to show that performance in the NL task, i.e. estimating the spatial position of a number on an interval, correlates with brain activity observed during single-digit subtraction problem in regions thought to be involved numerical magnitude and spatial processes. PMID:25497398

Electrophysiological Correlates of Non-Symbolic Numerical Magnitude Processing in Children: Joining the Dots

ERIC Educational Resources Information Center

Heine, Angela; Tamm, Sascha; Wissmann, Jacqueline; Jacobs, Arthur M.

2011-01-01

Whether and in what way enumeration processes differ for small and large sets of objects is still a matter of debate. In order to shed light on this issue, EEG data were obtained from 60 normally developing elementary school children. Adopting a standard non-symbolic numerical comparison paradigm allowed us to manipulate numerical distance between…

Spherical Pendulum Small Oscillations for Slewing Crane Motion

PubMed Central

Perig, Alexander V.; Stadnik, Alexander N.; Deriglazov, Alexander I.

2014-01-01

The present paper focuses on the Lagrange mechanics-based description of small oscillations of a spherical pendulum with a uniformly rotating suspension center. The analytical solution of the natural frequencies' problem has been derived for the case of uniform rotation of a crane boom. The payload paths have been found in the inertial reference frame fixed on earth and in the noninertial reference frame, which is connected with the rotating crane boom. The numerical amplitude-frequency characteristics of the relative payload motion have been found. The mechanical interpretation of the terms in Lagrange equations has been outlined. The analytical expression and numerical estimation for cable tension force have been proposed. The numerical computational results, which correlate very accurately with the experimental observations, have been shown. PMID:24526891

Numerical modelling of multimode fibre-optic communication lines

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

Sidelnikov, O S; Fedoruk, M P; Sygletos, S

The results of numerical modelling of nonlinear propagation of an optical signal in multimode fibres with a small differential group delay are presented. It is found that the dependence of the error vector magnitude (EVM) on the differential group delay can be reduced by increasing the number of ADC samples per symbol in the numerical implementation of the differential group delay compensation algorithm in the receiver. The possibility of using multimode fibres with a small differential group delay for data transmission in modern digital communication systems is demonstrated. It is shown that with increasing number of modes the strong couplingmore » regime provides a lower EVM level than the weak coupling one. (fibre-optic communication lines)« less

Comparison of eigenvectors for coupled seismo-electromagnetic layered-Earth modelling

NASA Astrophysics Data System (ADS)

Grobbe, N.; Slob, E. C.; Thorbecke, J. W.

2016-07-01

We study the accuracy and numerical stability of three eigenvector sets for modelling the coupled poroelastic and electromagnetic layered-Earth response. We use a known eigenvector set, its flux-normalized version and a newly derived flux-normalized set. The new set is chosen such that the system is properly uncoupled when the coupling between the poroelastic and electromagnetic fields vanishes. We carry out two different numerical stability tests: the first test focuses on the internal system, eigenvector and eigenvalue consistency; the second test investigates the stability and preciseness of the flux-normalized systems by looking at identity relations. We find that the known set shows the largest deviation for both tests, whereas the new set performs best. In two additional numerical modelling experiments, these numerical inaccuracies are shown to generate numerical noise levels comparable to small signals, such as signals coming from the important interface conversion responses, especially when the coupling coefficient is small. When coupling vanishes completely, the known set does not produce proper results. The new set produces numerically stable and accurate results in all situations. We therefore strongly recommend to use this newly derived set for future layered-Earth seismo-electromagnetic modelling experiments.

75 FR 36762 - Self-Regulatory Organizations; EDGA Exchange, Inc.; Notice of Filing of Proposed Rule Change, as...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-28

... Exchange is proposing to replace existing paragraph (c)(4) of Rule 11.13, entitled ``Numerical Guidelines... the ability of the Exchange to deviate from the Numerical Guidelines contained in paragraph (c)(1... of existing paragraph (c)(2), which provides flexibility to the Exchange to use different Numerical...

75 FR 36752 - Self-Regulatory Organizations; NASDAQ OMX BX, Inc.; Notice of Filing of a Proposed Rule Change...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-28

... Securities.'' Second, the Exchange is replacing existing paragraph (C)(4) of Rule 11890, entitled ``Numerical... the ability of the Exchange to deviate from the Numerical Guidelines contained in paragraph (C)(1... flexibility to the Exchange to use different Numerical Guidelines or Reference Prices in various ``Unusual...

Empty Sets as Part of the Numerical Continuum: Conceptual Precursors to the Zero Concept in Rhesus Monkeys

ERIC Educational Resources Information Center

Merritt, Dustin J.; Rugani, Rosa; Brannon, Elizabeth M.

2009-01-01

The goal of the current research was to explore whether monkeys possess conceptual precursors necessary for understanding zero. We trained rhesus monkeys on a nonsymbolic numerical matching-to-sample task, and on a numerical ordering task. We then introduced nondifferentially reinforced trials that contained empty sets to determine whether monkeys…

Distribution of enkephalin-like immunoreactivity in the cat digestive tract.

PubMed

Bagnol, D; Henry, M; Cupo, A; Julé, Y

1997-05-12

Immunohistochemical investigations were carried out to determine the pattern of distribution of methionine- and leucine-enkephalin-like materials in the cat pylorus, duodenum, ileum and proximal and distal colon. The present results indicate that leucine-enkephalin-like materials are less densely distributed than methionine-enkephalin-like materials, but that the two patterns of distribution show some similarities. Considerable regional differences exist however in the distribution of these enkephalin-like materials in the muscular layers. In the duodenum, ileum and proximal colon, the immunoreactivity was mainly confined to the myenteric plexus and the circular muscle layer, where it was present in nerve cell bodies and in numerous fibres. In the longitudinal muscle and submucous layers, a few immunoreactive fibres were observed which sometimes surrounded blood vessels. In the pylorus and the distal colon, however, numerous immunoreactive fibres were observed in the longitudinal and circular muscle layers; the immunoreactivity was detected in the cell bodies of numerous myenteric plexus neurons but those of only a few submucous plexus neurons. In addition, the pylorus tissues contained immunoreactive plexi which were localized either within the longitudinal muscle or between the serosa and the longitudinal muscle layer. These plexi were connected to the myenteric plexus by immunoreactive nerve strands. In all the small intestinal segments studied, numerous immunoreactive varicosities were present in the deep muscular plexus, in the inner part of the circular muscle layer. Our results suggest that in cats, the nervous control of external muscular layers mediated by enkephalins shows regional differences. In the pylorus and the distal colon, it involves both the longitudinal and circular muscle layers, whereas in other intestinal segments, only the circular muscle layer is involved.

The technique of numerical research of cooling medium flow in the water jacket of self-lubricated bearing

NASA Astrophysics Data System (ADS)

Raikovskiy, N. A.; Tretyakov, A. V.; Abramov, S. A.; Nazmeev, F. G.; Pavlichev, S. V.

2017-08-01

The paper presents a numerical study method of the cooling medium flowing in the water jacket of self-lubricating sliding bearing based on ANSYS CFX. The results of numerical calculations have satisfactory convergence with the empirical data obtained on the testbed. Verification data confirm the possibility of applying this numerical technique for the analysis of coolant flowings in the self-lubricating bearing containing the water jacket.

Spurious Numerical Solutions Of Differential Equations

NASA Technical Reports Server (NTRS)

Lafon, A.; Yee, H. C.

1995-01-01

Paper presents detailed study of spurious steady-state numerical solutions of differential equations that contain nonlinear source terms. Main objectives of this study are (1) to investigate how well numerical steady-state solutions of model nonlinear reaction/convection boundary-value problem mimic true steady-state solutions and (2) to relate findings of this investigation to implications for interpretation of numerical results from computational-fluid-dynamics algorithms and computer codes used to simulate reacting flows.

Small Group Activities for Introductory Business Classes.

ERIC Educational Resources Information Center

Mundrake, George

1999-01-01

Describes numerous small-group activities for the following areas of basic business education: consumer credit, marketing, business organization, entrepreneurship, insurance, risk management, economics, personal finance, business careers, global markets, and government regulation. (SK)

Development of Electrothermal Pulsed Plasma Thrusters for Osaka-Institute-of-Technology Electric-Rocket-Engine onboard Small Space Ship

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

Ishii, Yushuke; Yamamoto, Tsuyoshi; Yamada, Minetsugu

2008-12-31

The Project of Osaka-Institute-of-Technology Electric-Rocket-Engine onboard Small Space Ship (PROITERES) was started at Osaka Institute of Technology. In PROITERES, a 10-kg small satellite with electrothermal pulsed plasma thrusters (PPTs), named JOSHO, will be launched in 2010. The main mission is powered flight of small satellite by electric thruster itself. Electrothermal PPTs were studied with both experiments and numerical simulations. An electrothermal PPT with a side-fed propellant feeding mechanism achieved a total impulse of 3.6 Ns with a repetitive 10000-shot operation. An unsteady numerical simulation showed the existence of considerable amount of ablation delaying to the discharge. However, it was alsomore » shown that this phenomenon should not be regarded as the 'late time ablation' for electrothermal PPTs.« less

Detection of an abundant plant-based small RNA in consumers

USDA-ARS?s Scientific Manuscript database

Mechanisms of delivery of plant small RNAs to consumers must be addressed in order to harness this technology to positively impact agbiotechnology. Two groups have used honeysuckle (Lonicera japonica) feeding regimes to detect a plant-based small RNA, termed MIR2911, in sera. Meanwhile, numerous gro...

Small Schools, Big Future

ERIC Educational Resources Information Center

Halsey, R. John

2011-01-01

Historically, small schools have played a very important role in the provision of schooling in Australia. Numerically, using an enrollment of 200 or less, small schools represent approximately 45% of the schools in Australia. Population growth and the consequences of this, in particular for food production, water and energy, mean that the…

Analysis and algorithms for a regularized Cauchy problem arising from a non-linear elliptic PDE for seismic velocity estimation

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

Cameron, M.K.; Fomel, S.B.; Sethian, J.A.

2009-01-01

In the present work we derive and study a nonlinear elliptic PDE coming from the problem of estimation of sound speed inside the Earth. The physical setting of the PDE allows us to pose only a Cauchy problem, and hence is ill-posed. However we are still able to solve it numerically on a long enough time interval to be of practical use. We used two approaches. The first approach is a finite difference time-marching numerical scheme inspired by the Lax-Friedrichs method. The key features of this scheme is the Lax-Friedrichs averaging and the wide stencil in space. The second approachmore » is a spectral Chebyshev method with truncated series. We show that our schemes work because of (1) the special input corresponding to a positive finite seismic velocity, (2) special initial conditions corresponding to the image rays, (3) the fact that our finite-difference scheme contains small error terms which damp the high harmonics; truncation of the Chebyshev series, and (4) the need to compute the solution only for a short interval of time. We test our numerical scheme on a collection of analytic examples and demonstrate a dramatic improvement in accuracy in the estimation of the sound speed inside the Earth in comparison with the conventional Dix inversion. Our test on the Marmousi example confirms the effectiveness of the proposed approach.« less

Numerical simulation of systems of shear bands in ductile metal with inclusions

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

Plohr, JeeYeon N., E-mail: jplohr@lanl.gov; Plohr, Bradley J.

2016-02-15

We develop a method for numerical simulations of high strain-rate loading of mesoscale samples of ductile metal with inclusions. Because of its small-scale inhomogeneity, the composite material is prone to localized shear deformation (adiabatic shear bands). This method employs the Generalized Method of Cells of Paley and Aboudi [Mech. Materials, vol. 14, pp. 127–139, 1992] to ensure that the micro mechanical behavior of the metal and inclusions is reflected properly in the behavior of the composite at the mesoscale. To find the effective plastic strain rate when shear bands are present, we extend and apply the analytic and numerical analysismore » of shear bands of Glimm, Plohr, and Sharp [Mech. Materials, vol. 24, pp. 31–41, 1996]. Our tests of the method focus on the stress/strain response in uniaxial-strain flow, both compressive and tensile, of depleted uranium metal containing silicon carbide inclusions. We use the Preston-Tonks-Wallace viscoplasticity model [J. Appl. Phys., vol. 93, pp. 211–220, 2003], which applies to the high strain-rate regime of an isotropic viscoplastic solid. In results, we verify the elevated temperature and thermal softening at shear bands in our simulations of pure DU and DU/SiC composites. We also note that in composites, due the asymmetry caused by the inclusions, shear band form at different times in different subcells. In particular, in the subcells near inclusions, shear band form much earlier than they do in pure DU.« less

Wiggly tails: A gravitational wave signature of massive fields around black holes

NASA Astrophysics Data System (ADS)

Degollado, Juan Carlos; Herdeiro, Carlos A. R.

2014-09-01

Massive fields can exist in long-lived configurations around black holes. We examine how the gravitational wave signal of a perturbed black hole is affected by such "dirtiness" within linear theory. As a concrete example, we consider the gravitational radiation emitted by the infall of a massive scalar field into a Schwarzschild black hole. Whereas part of the scalar field is absorbed/scattered by the black hole and triggers gravitational wave emission, another part lingers in long-lived quasibound states. Solving numerically the Teukolsky master equation for gravitational perturbations coupled to the massive Klein-Gordon equation, we find a characteristic gravitational wave signal, composed by a quasinormal ringing followed by a late time tail. In contrast to "clean" black holes, however, the late time tail contains small amplitude wiggles with the frequency of the dominating quasibound state. Additionally, an observer dependent beating pattern may also be seen. These features were already observed in fully nonlinear studies; our analysis shows they are present at linear level, and, since it reduces to a 1+1 dimensional numerical problem, allows for cleaner numerical data. Moreover, we discuss the power law of the tail and that it only becomes universal sufficiently far away from the dirty black hole. The wiggly tails, by constrast, are a generic feature that may be used as a smoking gun for the presence of massive fields around black holes, either as a linear cloud or as fully nonlinear hair.

Numerical simulation of systems of shear bands in ductile metal with inclusions

NASA Astrophysics Data System (ADS)

Plohr, JeeYeon N.; Plohr, Bradley J.

2016-02-01

We develop a method for numerical simulations of high strain-rate loading of mesoscale samples of ductile metal with inclusions. Because of its small-scale inhomogeneity, the composite material is prone to localized shear deformation (adiabatic shear bands). This method employs the Generalized Method of Cells of Paley and Aboudi [Mech. Materials, vol. 14, pp. 127-139, 1992] to ensure that the micro mechanical behavior of the metal and inclusions is reflected properly in the behavior of the composite at the mesoscale. To find the effective plastic strain rate when shear bands are present, we extend and apply the analytic and numerical analysis of shear bands of Glimm, Plohr, and Sharp [Mech. Materials, vol. 24, pp. 31-41, 1996]. Our tests of the method focus on the stress/strain response in uniaxial-strain flow, both compressive and tensile, of depleted uranium metal containing silicon carbide inclusions. We use the Preston-Tonks-Wallace viscoplasticity model [J. Appl. Phys., vol. 93, pp. 211-220, 2003], which applies to the high strain-rate regime of an isotropic viscoplastic solid. In results, we verify the elevated temperature and thermal softening at shear bands in our simulations of pure DU and DU/SiC composites. We also note that in composites, due the asymmetry caused by the inclusions, shear band form at different times in different subcells. In particular, in the subcells near inclusions, shear band form much earlier than they do in pure DU.

Capillary Driven Flows Along Differentially Wetted Interior Corners

NASA Technical Reports Server (NTRS)

Golliher, Eric L. (Technical Monitor); Nardin, C. L.; Weislogel, M. M.

2005-01-01

Closed-form analytic solutions useful for the design of capillary flows in a variety of containers possessing interior corners were recently collected and reviewed. Low-g drop tower and aircraft experiments performed at NASA to date show excellent agreement between theory and experiment for perfectly wetting fluids. The analytical expressions are general in terms of contact angle, but do not account for variations in contact angle between the various surfaces within the system. Such conditions may be desirable for capillary containment or to compute the behavior of capillary corner flows in containers consisting of different materials with widely varying wetting characteristics. A simple coordinate rotation is employed to recast the governing system of equations for flows in containers with interior corners with differing contact angles on the faces of the corner. The result is that a large number of capillary driven corner flows may be predicted with only slightly modified geometric functions dependent on corner angle and the two (or more) contact angles of the system. A numerical solution is employed to verify the new problem formulation. The benchmarked computations support the use of the existing theoretical approach to geometries with variable wettability. Simple experiments to confirm the theoretical findings are recommended. Favorable agreement between such experiments and the present theory may argue well for the extension of the analytic results to predict fluid performance in future large length scale capillary fluid systems for spacecraft as well as for small scale capillary systems on Earth.

Influence of inorganic and organic selenium on number of living mycelial cells and their ultrastructure in culture of Hericium erinaceum (Bull.: Fr. Pers.).

PubMed

Slusarczyk, Joanna; Malinowska, Eliza; Krzyczkowski, W; Kuraś, M

2013-03-01

Mycelium of the white-rot fungus (Hericium erinaceum (Bull.: Fr. Pers.) produces polysaccharides showing anticancer and immunostimulating activity. In our previous works, we have shown that organic selenitetriglycerides (Selol) contribute to the increase of biosynthesis of exopolysaccharides (EPS) having antioxidative properties and containing large amounts of selenium. The present work is a study of influence of inorganic and organic form of selenium on viability of H. erinaceum mycelium and on ultrastructural changes taking place during its development in submerged culture. The mycelium was grown on media containing sodium selenite (Na2SeO3), a mixture of Na2SeO3 + Selol2% and on control medium (no selenium added). It was shown that mycelium cultured for 3 days in control conditions on standard media contained almost 100% of living cells, with over 80% after 24 days. Treatment with 100 ppm of Na2SeO3 lowered the number of viable cells to 11.8% and 9.1% after 3 and 24 days, respectively. The addition of 2% Selol caused the amounts of living cells to remain at ca 90%. Apparently, Selol helped the cells to cope with the toxic activity of inorganic selenium ions. The addition of sodium selenite induced degradative changes in cell organelles. Such changes were not observed in the case of Na2SeO3 + Selol mixture, in which case cells contained numerous ribosomes and small lipid bodies.

Bloch surface waves confined in one dimension with a single polymeric nanofibre

NASA Astrophysics Data System (ADS)

Wang, Ruxue; Xia, Hongyan; Zhang, Douguo; Chen, Junxue; Zhu, Liangfu; Wang, Yong; Yang, Erchan; Zang, Tianyang; Wen, Xiaolei; Zou, Gang; Wang, Pei; Ming, Hai; Badugu, Ramachandram; Lakowicz, Joseph R.

2017-02-01

Polymeric fibres with small radii (such as ≤125 nm) are delicate to handle and should be laid down on a solid substrate to obtain practical devices. However, placing these nanofibres on commonly used glass substrates prevents them from guiding light. In this study, we numerically and experimentally demonstrate that when the nanofibre is placed on a suitable dielectric multilayer, it supports a guided mode, a Bloch surface wave (BSW) confined in one dimension. The physical origin of this new mode is discussed in comparison with the typical two-dimensional BSW mode. Polymeric nanofibres are easily fabricated to contain fluorophores, which make the dielectric nanofibre and multilayer configuration suitable for developing a large range of new nanometric scale devices, such as processor-memory interconnections, devices with sensitivity to target analytes, incident polarization and multi-colour BSW modes.

Entropic stochastic resonance of a self-propelled Janus particle

NASA Astrophysics Data System (ADS)

Liu, Zhenzhen; Du, Luchun; Guo, Wei; Mei, Dong-Cheng

2016-10-01

Entropic stochastic resonance is investigated when a self-propelled Janus particle moves in a double-cavity container. Numerical simulation results indicate the entropic stochastic resonance can survive even if there is no symmetry breaking in any direction. This is the essential distinction between the property of a self-propelled Janus particle and that of a passive Brownian particle, for the symmetry breaking is necessary for the entropic stochastic resonance of a passive Brownian particle. With the rotational noise intensity growing at small fixed noise intensity of translational motion, the signal power amplification increases monotonically towards saturation which also can be regarded as a kind of stochastic resonance effect. Besides, the increase in the natural frequency of the periodic driving depresses the degree of the stochastic resonance, whereas the rise in its amplitude enhances and then suppresses the behavior.

Recent advances in intra-articular drug delivery systems for osteoarthritis therapy.

PubMed

Maudens, Pierre; Jordan, Olivier; Allémann, Eric

2018-05-21

Osteoarthritis (OA) is the most common degenerative disease of the joint. Despite many reports and numerous clinical trials, OA is not entirely understood, and there is no effective treatment available for this disease. To satisfy this unmet medical need, drug delivery systems (DDSs) containing disease-modifying OA drugs (DMOADs) for intra-articular (IA) administration are required to improve the health of OA patients. DDSs should provide controlled and/or sustained drug release, enabling long-term treatment with a reduced number of injections. This paper reviews the role and interaction among different tissues involved in OA and summarizes recent clinical trials and research on DDSs, focusing on small-molecule delivery. To achieve an ideal treatment, various key criteria have been identified to design and develop an IA DDS matching the clinical needs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Finite-difference time-domain analysis of photonic nanojets from liquid-crystal-containing microcylinder

NASA Astrophysics Data System (ADS)

Matsui, Tatsunosuke; Okajima, Akiko

2014-01-01

The photonic nanojet (PNJ) from a microcylinder with liquid crystals (LCs) showing tangential molecular alignment inside the microcylinder has been numerically analyzed on the basis of the finite-difference time-domain method. By introducing a small degree of birefringence, the characteristics of the PNJ, such as propagation length and polarization state, can be drastically changed. The azimuth angle and the ellipticity of the elliptically polarized PNJ obtained from the LC microcylinder changes within the propagation lengths in the micrometer range even in the isotropic matrix, which might be attributed to the jet like spatial profile of the PNJ. By using LC microcylinders or microspheres, we may obtain a rich variety of PNJs with unique polarization characteristics, which might open a new avenue for the development of novel optical devices with electrical tunability.

Observer-based output feedback control of networked control systems with non-uniform sampling and time-varying delay

NASA Astrophysics Data System (ADS)

Meng, Su; Chen, Jie; Sun, Jian

2017-10-01

This paper investigates the problem of observer-based output feedback control for networked control systems with non-uniform sampling and time-varying transmission delay. The sampling intervals are assumed to vary within a given interval. The transmission delay belongs to a known interval. A discrete-time model is first established, which contains time-varying delay and norm-bounded uncertainties coming from non-uniform sampling intervals. It is then converted to an interconnection of two subsystems in which the forward channel is delay-free. The scaled small gain theorem is used to derive the stability condition for the closed-loop system. Moreover, the observer-based output feedback controller design method is proposed by utilising a modified cone complementary linearisation algorithm. Finally, numerical examples illustrate the validity and superiority of the proposed method.

Discovery of skin alkaloids in a miniaturized eleutherodactylid frog from Cuba

PubMed Central

Rodríguez, Ariel; Poth, Dennis; Schulz, Stefan; Vences, Miguel

2011-01-01

Four phylogenetically independent lineages of frogs are currently known to sequester lipid-soluble skin alkaloids for which a dietary source has been demonstrated. We report here a remarkable fifth such instance, in Eleutherodactylus iberia and Eleutherodactylus orientalis, two species of miniaturized frogs of the family Eleutherodactylidae from Cuba. Six pumiliotoxins and two indolizidines were found in E. iberia, one of the smallest frogs in the world and characterized by a contrasting colour pattern for which we hypothesize an aposematic function. Analyses of stomach content indicated a numerical prevalence of mites with an important proportion of oribatids—a group of arthropods known to contain one of the pumiliotoxins detected in E. iberia. This suggests that miniaturization and specialization to small prey may have favoured the acquisition of dietary skin alkaloids in these amphibians. PMID:21047848

Speeding up GW Calculations to Meet the Challenge of Large Scale Quasiparticle Predictions

PubMed Central

Gao, Weiwei; Xia, Weiyi; Gao, Xiang; Zhang, Peihong

2016-01-01

Although the GW approximation is recognized as one of the most accurate theories for predicting materials excited states properties, scaling up conventional GW calculations for large systems remains a major challenge. We present a powerful and simple-to-implement method that can drastically accelerate fully converged GW calculations for large systems, enabling fast and accurate quasiparticle calculations for complex materials systems. We demonstrate the performance of this new method by presenting the results for ZnO and MgO supercells. A speed-up factor of nearly two orders of magnitude is achieved for a system containing 256 atoms (1024 valence electrons) with a negligibly small numerical error of ±0.03 eV. Finally, we discuss the application of our method to the GW calculations for 2D materials. PMID:27833140

Additional nuclear criticality safety calculations for small-diameter containers

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

Hone, M.J.

This report documents additional criticality safety analysis calculations for small diameter containers, which were originally documented in Reference 1. The results in Reference 1 indicated that some of the small diameter containers did not meet the criteria established for criticality safety at the Portsmouth facility (K{sub eff} +2{sigma}<.95) when modeled under various contingency assumptions of reflection and moderation. The calculations performed in this report reexamine those cases which did not meet the criticality safety criteria. In some cases, unnecessary conservatism is removed, and in other cases mass or assay limits are established for use with the respective containers.

System Simulation by Recursive Feedback: Coupling a Set of Stand-Alone Subsystem Simulations

NASA Technical Reports Server (NTRS)

Nixon, D. D.

2001-01-01

Conventional construction of digital dynamic system simulations often involves collecting differential equations that model each subsystem, arran g them to a standard form, and obtaining their numerical gin solution as a single coupled, total-system simultaneous set. Simulation by numerical coupling of independent stand-alone subsimulations is a fundamentally different approach that is attractive because, among other things, the architecture naturally facilitates high fidelity, broad scope, and discipline independence. Recursive feedback is defined and discussed as a candidate approach to multidiscipline dynamic system simulation by numerical coupling of self-contained, single-discipline subsystem simulations. A satellite motion example containing three subsystems (orbit dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Distributed and centralized implementations of coupling have been considered. Numerical results are evaluated by direct comparison with a standard total-system, simultaneous-solution approach.

Children’s Numerical Equivalence Judgments: Crossmapping Effects

PubMed Central

Mix, Kelly S.

2009-01-01

Preschoolers made numerical comparisons between sets with varying degrees of shared surface similarity. When surface similarity was pitted against numerical equivalence (i.e., crossmapping), children made fewer number matches than when surface similarity was neutral (i.e, all sets contained the same objects). Only children who understood the number words for the target sets performed above chance in the crossmapping condition. These findings are consistent with previous research on children’s non-numerical comparisons (e.g., Rattermann & Gentner, 1998; Smith, 1993) and suggest that the same mechanisms may underlie numerical development. PMID:19655027

Aural detection of small propeller-driven aircraft

DOT National Transportation Integrated Search

1987-10-31

The Federal Aviation Administration (FAA) has conducted numerous flight tests of small propeller-driven aircraft in support of developing aircraft noise regulations. Those test typically measured ground-level noise resulting from high power/high RPM ...

Boron cage compound materials and composites for shielding and absorbing neutrons

DOEpatents

Bowen, III, Daniel E; Eastwood, Eric A

2014-03-04

Boron cage compound-containing materials for shielding and absorbing neutrons. The materials include BCC-containing composites and compounds. BCC-containing compounds comprise a host polymer and a BCC attached thereto. BCC-containing composites comprise a mixture of a polymer matrix and a BCC filler. The BCC-containing materials can be used to form numerous articles of manufacture for shielding and absorbing neutrons.

Equations to assess the impact resistance of fiber composites

NASA Technical Reports Server (NTRS)

Chamis, C. C.; Hanson, M. P.; Serafini, T. T.

1972-01-01

Numerical analysis of impact resistance of composite materials containing fibers is discussed. Mathematical model of longitudinal impact resistance is presented. Potential impact resistance of various fiber composites as obtained by numerical analysis is presented as plotted curve.

Application of dual-energy x-ray techniques for automated food container inspection

NASA Astrophysics Data System (ADS)

Shashishekhar, N.; Veselitza, D.

2016-02-01

Manufacturing for plastic food containers often results in small metal particles getting into the containers during the production process. Metal detectors are usually not sensitive enough to detect these metal particles (0.5 mm or lesser), especially when the containers are stacked in large sealed shipping packages; X-ray inspection of these packages provides a viable alternative. This paper presents the results of an investigation into dual-energy X-ray techniques for automated detection of small metal particles in plastic food container packages. The sample packages consist of sealed cardboard boxes containing stacks of food containers: plastic cups for food, and Styrofoam cups for noodles. The primary goal of the investigation was to automatically identify small metal particles down to 0.5 mm diameter in size or less, randomly located within the containers. The multiple container stacks in each box make it virtually impossible to reliably detect the particles with single-energy X-ray techniques either visually or with image processing. The stacks get overlaid in the X-ray image and create many indications almost identical in contrast and size to real metal particles. Dual-energy X-ray techniques were investigated and found to result in a clear separation of the metal particles from the food container stack-ups. Automated image analysis of the resulting images provides reliable detection of the small metal particles.

Universal Profile of the Vortex Condensate in Two-Dimensional Turbulence

NASA Astrophysics Data System (ADS)

Laurie, Jason; Boffetta, Guido; Falkovich, Gregory; Kolokolov, Igor; Lebedev, Vladimir

2014-12-01

An inverse turbulent cascade in a restricted two-dimensional periodic domain creates a condensate—a pair of coherent system-size vortices. We perform extensive numerical simulations of this system and carry out theoretical analysis based on momentum and energy exchanges between the turbulence and the vortices. We show that the vortices have a universal internal structure independent of the type of small-scale dissipation, small-scale forcing, and boundary conditions. The theory predicts not only the vortex inner region profile, but also the amplitude, which both perfectly agree with the numerical data.

Efficient Numeric and Geometric Computations using Heterogeneous Shared Memory Architectures

DTIC Science & Technology

2017-10-04

Report: Efficient Numeric and Geometric Computations using Heterogeneous Shared Memory Architectures The views, opinions and/or findings contained in this...Chapel Hill Title: Efficient Numeric and Geometric Computations using Heterogeneous Shared Memory Architectures Report Term: 0-Other Email: dm...algorithms for scientific and geometric computing by exploiting the power and performance efficiency of heterogeneous shared memory architectures . These

Numerical comparison of exhaust plume flow behaviors of small monopropellant and bipropellant thrusters

PubMed Central

2017-01-01

In general, a space propulsion system has a crucial role in the normal mission operations of a spacecraft. Depending on the types and number of propellants, a monopropellant and a bipropellant thrusters are mostly utilized for low thrust liquid rocket engines. As the plume gas flow exhausted from these small thrusters expands freely in a vacuum space environment along all directions, adverse effects of the plume impingement onto the spacecraft surfaces can dramatically reduce the function and performance of a spacecraft. Thus, the purpose of the present study is to investigate and compare the major differences of the plume gas flow behaviors numerically between the small monopropellant and bipropellant thrusters. To ensure efficient numerical calculations, the whole physical domain was divided into three different subdomains depending on the flow conditions, and then the appropriate numerical methods were combined and applied for each subdomain sequentially. With the present analysis results, the plume gas behaviors including the density, the overall temperature and the separation of the chemical species are compared and discussed between the monopropellant and the bipropellant thrusters. Consequently, the present results are expected to provide useful information on selecting the appropriate propulsion system, which can be very helpful for actual engineers practically during the design process. PMID:28481892

Nonlinear dynamo action in a precessing cylindrical container.

PubMed

Nore, C; Léorat, J; Guermond, J-L; Luddens, F

2011-07-01

It is numerically demonstrated by means of a magnetohydrodynamics code that precession can trigger the dynamo effect in a cylindrical container. When the Reynolds number, based on the radius of the cylinder and its angular velocity, increases, the flow, which is initially centrosymmetric, loses its stability and bifurcates to a quasiperiodic motion. This unsteady and asymmetric flow is shown to be capable of sustaining dynamo action in the linear and nonlinear regimes. The magnetic field thus generated is unsteady and quadrupolar. These numerical evidences of dynamo action in a precessing cylindrical container may be useful for an experiment now planned at the Dresden sodium facility for dynamo and thermohydraulic studies in Germany.

The NLO jet vertex in the small-cone approximation for kt and cone algorithms

NASA Astrophysics Data System (ADS)

Colferai, D.; Niccoli, A.

2015-04-01

We determine the jet vertex for Mueller-Navelet jets and forward jets in the small-cone approximation for two particular choices of jet algoritms: the kt algorithm and the cone algorithm. These choices are motivated by the extensive use of such algorithms in the phenomenology of jets. The differences with the original calculations of the small-cone jet vertex by Ivanov and Papa, which is found to be equivalent to a formerly algorithm proposed by Furman, are shown at both analytic and numerical level, and turn out to be sizeable. A detailed numerical study of the error introduced by the small-cone approximation is also presented, for various observables of phenomenological interest. For values of the jet "radius" R = 0 .5, the use of the small-cone approximation amounts to an error of about 5% at the level of cross section, while it reduces to less than 2% for ratios of distributions such as those involved in the measure of the azimuthal decorrelation of dijets.

Investigating the structure of a vortex flow in the closed polygonal containers

NASA Astrophysics Data System (ADS)

Podolskaya, I. Yu; Bakakin, G. V.; Naumov, I. V.

2018-03-01

The structure of confined vortex flow generated by a rotating lid in a closed container with polygonal cross-section geometry (eight, six and five angles) has been investigated numerically for different height/radius aspect ratios h from 3.0 to 4.5 and for Reynold numbers ranging from 1500 to 3000. The critical Reynolds numbers at which the flow becomes unsteady were determined numerically by STAR-CCM+ computational fluid dynamics software for pentagonal and hexagonal cross-section configurations. The obtained results were compared with the flow structure in the closed cylindrical container. The boundary of a nonstationarity in polygonal containers is found to shift to the region of smaller aspect ratio and smaller Reynolds numbers with a decrease in the number of angles in the cross-section of the container relative to the boundary in a cylindrical container. It is additionally established that the structure of the flow in the near-axis region remains similar to the vortex structure in the cylinder, therefore the shape of the container does not influence the near-axis region.

Immediate Small Number Perception : Evidence from a New Numerical Carry-Over Procedure

ERIC Educational Resources Information Center

Demeyere, Nele; Humphreys, Glyn W.

2012-01-01

Evidence is presented for the immediate apprehension of exact small quantities. Participants performed a quantification task (are the number of items greater or smaller than?), and carry-over effects were examined between numbers requiring the same response. Carry-over effects between small numbers were strongly affected by repeats of pattern and…

Adequacy-Based Funding for Small, Isolated Schools: An Approach for Maine

ERIC Educational Resources Information Center

Allen, Debra M.; Sloan, James E.

2005-01-01

How to adequately fund small schools is becoming a pressing issue in Maine due to numerous factors, including state and federal accountability laws and declining enrollments. The following were among the challenges facing small rural schools: (a) attracting and retaining qualified teachers, (b) attracting and retaining qualified specialty teachers…

Modifications in small nuclear RNAs and their roles in spliceosome assembly and function.

PubMed

Bohnsack, Markus T; Sloan, Katherine E

2018-06-01

Modifications in cellular RNAs have emerged as key regulators of all aspects of gene expression, including pre-mRNA splicing. During spliceosome assembly and function, the small nuclear RNAs (snRNAs) form numerous dynamic RNA-RNA and RNA-protein interactions, which are required for spliceosome assembly, correct positioning of the spliceosome on substrate pre-mRNAs and catalysis. The human snRNAs contain several base methylations as well as a myriad of pseudouridines and 2'-O-methylated nucleotides, which are largely introduced by small Cajal body-specific-RNPs. Modified nucleotides typically cluster in functionally important regions of the snRNAs, suggesting that their presence could optimise the interactions of snRNAs with each other or with pre-mRNAs, or may affect the binding of spliceosomal proteins. snRNA modifications appear to play important roles in snRNP biogenesis and spliceosome assembly, and have also been proposed to influence the efficiency and fidelity of pre-mRNAs splicing. Interestingly, alterations in the modification status of snRNAs have recently been observed in different cellular conditions, implying that some snRNA modifications are dynamic and raising the possibility that these modifications may fine-tune the spliceosome for particular functions. Here, we review the current knowledge on the snRNA modification machinery and discuss the timing, functions and dynamics of modifications in snRNAs.

Model for small arms fire muzzle blast wave propagation in air

NASA Astrophysics Data System (ADS)

Aguilar, Juan R.; Desai, Sachi V.

2011-11-01

Accurate modeling of small firearms muzzle blast wave propagation in the far field is critical to predict sound pressure levels, impulse durations and rise times, as functions of propagation distance. Such a task being relevant to a number of military applications including the determination of human response to blast noise, gunfire detection and localization, and gun suppressor design. Herein, a time domain model to predict small arms fire muzzle blast wave propagation is introduced. The model implements a Friedlander wave with finite rise time which diverges spherically from the gun muzzle. Additionally, the effects in blast wave form of thermoviscous and molecular relaxational processes, which are associated with atmospheric absorption of sound were also incorporated in the model. Atmospheric absorption of blast waves is implemented using a time domain recursive formula obtained from numerical integration of corresponding differential equations using a Crank-Nicholson finite difference scheme. Theoretical predictions from our model were compared to previously recorded real world data of muzzle blast wave signatures obtained by shooting a set different sniper weapons of varying calibers. Recordings containing gunfire acoustical signatures were taken at distances between 100 and 600 meters from the gun muzzle. Results shows that predicted blast wave slope and exponential decay agrees well with measured data. Analysis also reveals the persistency of an oscillatory phenomenon after blast overpressure in the recorded wave forms.

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

Zhang, Jiangjiang; Li, Weixuan; Lin, Guang

In decision-making for groundwater management and contamination remediation, it is important to accurately evaluate the probability of the occurrence of a failure event. For small failure probability analysis, a large number of model evaluations are needed in the Monte Carlo (MC) simulation, which is impractical for CPU-demanding models. One approach to alleviate the computational cost caused by the model evaluations is to construct a computationally inexpensive surrogate model instead. However, using a surrogate approximation can cause an extra error in the failure probability analysis. Moreover, constructing accurate surrogates is challenging for high-dimensional models, i.e., models containing many uncertain input parameters.more » To address these issues, we propose an efficient two-stage MC approach for small failure probability analysis in high-dimensional groundwater contaminant transport modeling. In the first stage, a low-dimensional representation of the original high-dimensional model is sought with Karhunen–Loève expansion and sliced inverse regression jointly, which allows for the easy construction of a surrogate with polynomial chaos expansion. Then a surrogate-based MC simulation is implemented. In the second stage, the small number of samples that are close to the failure boundary are re-evaluated with the original model, which corrects the bias introduced by the surrogate approximation. The proposed approach is tested with a numerical case study and is shown to be 100 times faster than the traditional MC approach in achieving the same level of estimation accuracy.« less

Re-Computation of Numerical Results Contained in NACA Report No. 496

NASA Technical Reports Server (NTRS)

Perry, Boyd, III

2015-01-01

An extensive examination of NACA Report No. 496 (NACA 496), "General Theory of Aerodynamic Instability and the Mechanism of Flutter," by Theodore Theodorsen, is described. The examination included checking equations and solution methods and re-computing interim quantities and all numerical examples in NACA 496. The checks revealed that NACA 496 contains computational shortcuts (time- and effort-saving devices for engineers of the time) and clever artifices (employed in its solution methods), but, unfortunately, also contains numerous tripping points (aspects of NACA 496 that have the potential to cause confusion) and some errors. The re-computations were performed employing the methods and procedures described in NACA 496, but using modern computational tools. With some exceptions, the magnitudes and trends of the original results were in fair-to-very-good agreement with the re-computed results. The exceptions included what are speculated to be computational errors in the original in some instances and transcription errors in the original in others. Independent flutter calculations were performed and, in all cases, including those where the original and re-computed results differed significantly, were in excellent agreement with the re-computed results. Appendix A contains NACA 496; Appendix B contains a Matlab(Reistered) program that performs the re-computation of results; Appendix C presents three alternate solution methods, with examples, for the two-degree-of-freedom solution method of NACA 496; Appendix D contains the three-degree-of-freedom solution method (outlined in NACA 496 but never implemented), with examples.

Capuchin monkeys (Cebus apella) treat small and large numbers of items similarly during a relative quantity judgment task.

PubMed

Beran, Michael J; Parrish, Audrey E

2016-08-01

A key issue in understanding the evolutionary and developmental emergence of numerical cognition is to learn what mechanism(s) support perception and representation of quantitative information. Two such systems have been proposed, one for dealing with approximate representation of sets of items across an extended numerical range and another for highly precise representation of only small numbers of items. Evidence for the first system is abundant across species and in many tests with human adults and children, whereas the second system is primarily evident in research with children and in some tests with non-human animals. A recent paper (Choo & Franconeri, Psychonomic Bulletin & Review, 21, 93-99, 2014) with adult humans also reported "superprecise" representation of small sets of items in comparison to large sets of items, which would provide more support for the presence of a second system in human adults. We first presented capuchin monkeys with a test similar to that of Choo and Franconeri in which small or large sets with the same ratios had to be discriminated. We then presented the same monkeys with an expanded range of comparisons in the small number range (all comparisons of 1-9 items) and the large number range (all comparisons of 10-90 items in 10-item increments). Capuchin monkeys showed no increased precision for small over large sets in making these discriminations in either experiment. These data indicate a difference in the performance of monkeys to that of adult humans, and specifically that monkeys do not show improved discrimination performance for small sets relative to large sets when the relative numerical differences are held constant.

76 FR 14687 - In the Matter of Certain Semiconductor Chips and Products Containing Same; Notice of Commission...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-17

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-753] In the Matter of Certain Semiconductor Chips and Products Containing Same; Notice of Commission Determination Not To Review an Initial... semiconductor chips and products containing the same. The Commission's notice of investigation named numerous...

Change in Minimum Orbit Intersection Distance due to General Relativistic Precession in Small Solar System Bodies

NASA Astrophysics Data System (ADS)

Sekhar, Aswin; Valsecchi, Giovanni B.; Asher, David; Werner, Stephanie; Vaubaillon, Jeremie; Li, Gongjie

2017-06-01

One of the greatest successes of Einstein's General Theory of Relativity (GR) was the correct prediction of the perihelion precession of Mercury. The closed form expression to compute this precession tells us that substantial GR precession would occur only if the bodies have a combination of both moderately small perihelion distance and semi-major axis. Minimum Orbit Intersection Distance (MOID) is a quantity which helps us to understand the closest proximity of two orbits in space. Hence evaluating MOID is crucial to understand close encounters and collision scenarios better. In this work, we look at the possible scenarios where a small GR precession in argument of pericentre can create substantial changes in MOID for small bodies ranging from meteoroids to comets and asteroids.Previous works have looked into neat analytical techniques to understand different collision scenarios and we use those standard expressions to compute MOID analytically. We find the nature of this mathematical function is such that a relatively small GR precession can lead to drastic changes in MOID values depending on the initial value of argument of pericentre. Numerical integrations were done with the MERCURY package incorporating GR code to test the same effects. A numerical approach showed the same interesting relationship (as shown by analytical theory) between values of argument of pericentre and the peaks or dips in MOID values. There is an overall agreement between both analytical and numerical methods.We find that GR precession could play an important role in the calculations pertaining to MOID and close encounter scenarios in the case of certain small solar system bodies (depending on their initial orbital elements) when long term impact risk possibilities are considered. Previous works have looked into impact probabilities and collision scenarios on planets from different small body populations. This work aims to find certain sub-sets of small bodies where GR could play an interesting role. Certain parallels are drawn between the cases of asteroids, comets and small perihelion distance meteoroid streams.

High-Speed Edge-Detecting Line Scan Smart Camera

NASA Technical Reports Server (NTRS)

Prokop, Norman F.

2012-01-01

A high-speed edge-detecting line scan smart camera was developed. The camera is designed to operate as a component in a NASA Glenn Research Center developed inlet shock detection system. The inlet shock is detected by projecting a laser sheet through the airflow. The shock within the airflow is the densest part and refracts the laser sheet the most in its vicinity, leaving a dark spot or shadowgraph. These spots show up as a dip or negative peak within the pixel intensity profile of an image of the projected laser sheet. The smart camera acquires and processes in real-time the linear image containing the shock shadowgraph and outputting the shock location. Previously a high-speed camera and personal computer would perform the image capture and processing to determine the shock location. This innovation consists of a linear image sensor, analog signal processing circuit, and a digital circuit that provides a numerical digital output of the shock or negative edge location. The smart camera is capable of capturing and processing linear images at over 1,000 frames per second. The edges are identified as numeric pixel values within the linear array of pixels, and the edge location information can be sent out from the circuit in a variety of ways, such as by using a microcontroller and onboard or external digital interface to include serial data such as RS-232/485, USB, Ethernet, or CAN BUS; parallel digital data; or an analog signal. The smart camera system can be integrated into a small package with a relatively small number of parts, reducing size and increasing reliability over the previous imaging system..

The Orbits and Masses of Pluto's Satellites

NASA Astrophysics Data System (ADS)

Jacobson, Robert A.; Brozovic, M.

2012-10-01

We have fit numerically integrated orbits of Pluto's satellites, Charon, Nix, Hydra, and S/2011 (134340) 1, to an extensive set of astrometric, mutual event, and stellar occultation observations over the time interval April 1965 to July 2011. We did not include the newly discovered satellite S/2012 (134340) 1 because its observation set is insufficient to constrain a numerically integrated orbit. The data set contains all of the HST observations of Charon relative to Pluto which have been corrected for the Pluto center-of-figure center-of-light (COF) offset due to the Pluto albedo variations (Buie et al. 2012 AJ submitted). Buie et al. (2010 AJ 139, 1117 and 1128) discuss the development of the albedo model and the COF offset. We applied COF offset corrections to the remainder of the Pluto relative observations where applicable. The dual stellar occultations in 2008 and 2011 provided precise Pluto_Charon relative positions. We obtain a well determined value for the Pluto system mass, however, the lack of orbital resonances in the system makes it difficult to determine the satellite masses. The primary source of information for the Charon mass is a small quantity of absolute position measurements which are sensitive to the independent motions of Pluto and Charon about the system barycenter. The long term dynamical interaction among the satellites yields a weak determination of Hydra's mass; the masses of the other two satellites are found to be small but indeterminate. We have delivered ephemerides based on our integrated orbits to the New Horizons project along with their expected uncertainties at the time of the New Horizons encounter with the Pluto system. Acknowledgments: The research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

Vortex generator design for aircraft inlet distortion as a numerical optimization problem

NASA Technical Reports Server (NTRS)

Anderson, Bernhard H.; Levy, Ralph

1991-01-01

Aerodynamic compatibility of aircraft/inlet/engine systems is a difficult design problem for aircraft that must operate in many different flight regimes. Takeoff, subsonic cruise, supersonic cruise, transonic maneuvering, and high altitude loiter each place different constraints on inlet design. Vortex generators, small wing like sections mounted on the inside surfaces of the inlet duct, are used to control flow separation and engine face distortion. The design of vortex generator installations in an inlet is defined as a problem addressable by numerical optimization techniques. A performance parameter is suggested to account for both inlet distortion and total pressure loss at a series of design flight conditions. The resulting optimization problem is difficult since some of the design parameters take on integer values. If numerical procedures could be used to reduce multimillion dollar development test programs to a small set of verification tests, numerical optimization could have a significant impact on both cost and elapsed time to design new aircraft.

Thermal conductivity of an imperfect anharmonic crystal

NASA Astrophysics Data System (ADS)

Sahu, D. N.; Sharma, P. K.

1983-09-01

The thermal conductivity of an anharmonic crystal containing randomly distributed substitutional defects due to impurity-phonon scattering is theoretically investigated with the use of the method of double-time thermal Green's functions and the Kubo formalism considering all the terms, i.e., diagonal, nondiagonal, cubic anharmonic, and imperfection terms in the energy-flux operator as propounded by Hardy. The study uses cubic, quartic anharmonic, and defect terms in the Hamiltonian. Mass changes as well as force-constant changes between impurity and host-lattice atoms are taken into account explicitly. It is shown that the total conductivity can be written as a sum of contributions, namely diagonal, nondiagonal, anharmonic, and imperfection contributions. For phonons of small halfwidth, the diagonal contribution has precisely the same form which is obtained from Boltzmann's transport equation for impurity scattering in the relaxation-time approximation. The present study shows that there is a finite contribution of the nondiagonal term, cubic anharmonic term, and the term due to lattice imperfections in the energy-flux operator to the thermal conductivity although the contribution is small compared with that from the diagonal part. We have also discussed the feasibility of numerical evaluation of the various contributions to the thermal conductivity.

Transport properties of soil particles in Sakiyamawan-Amitoriwan nature conservation area, Iriomote Island, Japan

NASA Astrophysics Data System (ADS)

Shimokawa, Shinya; Murakami, Tomokazu; Kohno, Hiroyoshi; Mizutani, Akira

2017-12-01

The actual states of soil particle transport in and exchange between the Sakiyama and Amitori bays, Iriomote Island, Japan, were investigated using atmosphere-ocean-river observations and numerical simulations. The results show that in summer in both bays large particles (≥15 μm) do not move from the vicinity of the river mouths. Small particles, however, do move to the respective east sides of the bays. In winter in both the bays, large particles move towards the center of the bays from the vicinity of the river mouths, whereas small particles move to the respective west sides of the bays. Furthermore, soil particles move mainly from the Sakiyama to the Amitori bay in summer, but this direction is reversed in winter. These features are explainable mainly by seasonal differences in wind speed and direction, but the combination among seasonal differences in wind speed and direction, the wind-driven current and the topography is also important for them. The results are useful for assessing soil particle impact on coastal marine ecosystems, such as those containing reef-building coral and Enhalus acoroides, and their effective conservation in the natural conservation areas of the Sakiyama and Amitori bays.

Small GTPase Sar1 is crucial for proglutelin and α-globulin export from the endoplasmic reticulum in rice endosperm.

PubMed

Tian, Lihong; Dai, Ling Ling; Yin, Zhi Jie; Fukuda, Masako; Kumamaru, Toshihiro; Dong, Xiang Bai; Xu, Xiu Ping; Qu, Le Qing

2013-07-01

Rice seed storage proteins glutelin and α-globulin are synthesized in the endoplasmic reticulum (ER) and deposited in protein storage vacuoles (PSVs). Sar1, a small GTPase, acts as a molecular switch to regulate the assembly of coat protein complex II, which exports secretory protein from the ER to the Golgi apparatus. To reveal the route by which glutelin and α-globulin exit the ER, four putative Sar1 genes (OsSar1a/b/c/d) were cloned from rice, and transgenic rice were generated with Sar1 overexpressed or suppressed by RNA interference (RNAi) specifically in the endosperm under the control of the rice glutelin promoter. Overexpression or suppression of any OsSar1 did not alter the phenotype. However, simultaneous knockdown of OsSar1a/b/c resulted in floury and shrunken seeds, with an increased level of glutelin precursor and decreased level of the mature α- and β-subunit. OsSar1abc RNAi endosperm generated numerous, spherical, novel protein bodies with highly electron-dense matrixes containing both glutelin and α-globulin. Notably, the novel protein bodies were surrounded by ribosomes, showing that they were derived from the ER. Some of the ER-derived dense protein bodies were attached to a blebbing structure containing prolamin. These results indicated that OsSar1a/b/c play a crucial role in storage proteins exiting from the ER, with functional redundancy in rice endosperm, and glutelin and α-globulin transported together from the ER to the Golgi apparatus by a pathway mediated by coat protein complex II.

Observations of volcanic tremor during January-February 2005 eruption of Mt. Veniaminof, Alaska

USGS Publications Warehouse

De Angelis, Slivio; McNutt, Stephen R.

2007-01-01

Mt. Veniaminof, Alaska Peninsula, is a stratovolcano with a summit ice-filled caldera containing a small intracaldera cone and active vent. From January 2 to February 21, 2005, Mt. Veniaminof erupted. The eruption was characterized by numerous small ash emissions (VEI 0 to 1) and accompanied by low-frequency earthquake activity and volcanic tremor. We have performed spectral analyses of the seismic signals in order to characterize them and to constrain their source. Continuous tremor has durations of minutes to hours with dominant energy in the band 0.5– 4.0 Hz, and spectra characterized by narrow peaks either irregularly (non-harmonic tremor) or regularly spaced (harmonic tremor). The spectra of non-harmonic tremor resemble those of low-frequency events recorded simultaneously with surface ash explosions, suggesting that the source mechanisms might be similar or related. We propose that non-harmonic tremor at Mt. Veniaminof results from the coalescence of gas bubbles while low-frequency events are related to the disruption of large gas pockets within the conduit. Harmonic tremor, characterized by regular and quasisinusoidal waveforms, has duration of hours. Spectra containing up to five harmonics suggest the presence of a resonating source volume that vibrates in a longitudinal acoustic mode. An interesting feature of harmonic tremor is that frequency is observed to change over time; spectral lines move towards higher or lower values while the harmonic nature of the spectra is maintained. Factors controlling the variable characteristics of harmonic tremor include changes in acoustic velocity at the source and variations of the effective size of the resonator.

Macrocyclic lactones in the treatment and control of parasitism in small companion animals.

PubMed

Nolan, Thomas J; Lok, James B

2012-05-01

Macrocyclic lactones (MLs) have many anti-parasitic applications in small companion animal medicine. They were first developed as chemoprophylactics against heartworm (Dirofilaria immitis) infection to be applied monthly for retroactive killing of third- and fourth-stage larvae. ML-containing products formulated for oral (ivermectin, milbemycin oxime), topical (selamectin, moxidectin) or injectable sustained release (moxidectin, ivermectin) are approved for heartworm prevention in dogs or cats. Clearance of microfilariae and gradual or "soft" killing of adult heartworms constitute increasingly prevalent extra-label uses of MLs against D. immitis. Some commercial ML formulations contain sufficient levels of active ingredient (milbemycin oxime, selamectin, moxidectin) to support additional label claims against gastrointestinal nematode parasites such as hookworms (Ancylostoma spp.) and ascarid round worms (Toxocara spp. and Toxascaris leonina). Beyond these approved applications, safe, extra-label uses of MLs against nematodes parasitizing the urinary tract, such as Capillaria spp., and parasites of the tissues, such as Dipetalonema reconditum, Dirofilaria repens, Thelazia spp. and Spirocerca lupi, in dogs and cats as well as exotic pets have been reported. MLs as a group have intrinsic insecticidal and acaricidal activity, and topical or otic formulations of certain compounds (selamectin, moxidectin, milbemycin oxime or ivermectin) are approved for treatment and control of fleas, certain ixodid ticks, sarcoptiform and demodectic mange mites and psoroptiform ear mites. Extra-label applications of MLs against ectoparasites include notoedric mange mites, dermanyssids such as Ornythonussus bacoti, numerous species of fur mite (e.g. Cheyletiella spp. and Lynxacarus) and trombiculids ("chiggers") in cats, dogs and nontraditional or exotic pets.

The Effect of Boiling on Seismic Properties of Water-Saturated Fractured Rock

NASA Astrophysics Data System (ADS)

Grab, Melchior; Quintal, Beatriz; Caspari, Eva; Deuber, Claudia; Maurer, Hansruedi; Greenhalgh, Stewart

2017-11-01

Seismic campaigns for exploring geothermal systems aim at detecting permeable formations in the subsurface and evaluating the energy state of the pore fluids. High-enthalpy geothermal resources are known to contain fluids ranging from liquid water up to liquid-vapor mixtures in regions where boiling occurs and, ultimately, to vapor-dominated fluids, for instance, if hot parts of the reservoir get depressurized during production. In this study, we implement the properties of single- and two-phase fluids into a numerical poroelastic model to compute frequency-dependent seismic velocities and attenuation factors of a fractured rock as a function of fluid state. Fluid properties are computed while considering that thermodynamic interaction between the fluid phases takes place. This leads to frequency-dependent fluid properties and fluid internal attenuation. As shown in a first example, if the fluid contains very small amounts of vapor, fluid internal attenuation is of similar magnitude as attenuation in fractured rock due to other mechanisms. In a second example, seismic properties of a fractured geothermal reservoir with spatially varying fluid properties are calculated. Using the resulting seismic properties as an input model, the seismic response of the reservoir is then computed while the hydrothermal structure is assumed to vary over time. The resulting seismograms demonstrate that anomalies in the seismic response due to fluid state variability are small compared to variations caused by geological background heterogeneity. However, the hydrothermal structure in the reservoir can be delineated from amplitude anomalies when the variations due to geology can be ruled out such as in time-lapse experiments.

Spherical collapse of supermassive stars: Neutrino emission and gamma-ray bursts

NASA Astrophysics Data System (ADS)

Linke, F.; Font, J. A.; Janka, H.-T.; Müller, E.; Papadopoulos, P.

2001-09-01

We present the results of numerical simulations of the spherically symmetric gravitational collapse of supermassive stars (SMS). The collapse is studied using a general relativistic hydrodynamics code. The coupled system of Einstein and fluid equations is solved employing coordinates adapted to a foliation of the spacetime by means of outgoing null hypersurfaces. The code contains an equation of state which includes effects due to radiation, electrons and baryons, and detailed microphysics to account for electron-positron pairs. In addition energy losses by thermal neutrino emission are included. We are able to follow the collapse of SMS from the onset of instability up to the point of black hole formation. Several SMS with masses in the range 5x 105 Msun-109 Msun are simulated. In all models an apparent horizon forms initially, enclosing the innermost 25% of the stellar mass. From the computed neutrino luminosities, estimates of the energy deposition by nu bar nu-annihilation are obtained. Only a small fraction of this energy is deposited near the surface of the star, where, as proposed recently by Fuller & Shi (\\cite{Fuller98}), it could cause the ultrarelativistic flow believed to be responsible for gamma -ray bursts. Our simulations show that for collapsing SMS with masses larger than 5x 105 Msun the energy deposition is at least two orders of magnitude too small to explain the energetics of observed long-duration bursts at cosmological redshifts. In addition, in the absence of rotational effects the energy is deposited in a region containing most of the stellar mass. Therefore relativistic ejection of matter is impossible.

Improving the detection of pathways in genome-wide association studies by combined effects of SNPs from Linkage Disequilibrium blocks.

PubMed

Zhao, Huiying; Nyholt, Dale R; Yang, Yuanhao; Wang, Jihua; Yang, Yuedong

2017-06-14

Genome-wide association studies (GWAS) have successfully identified single variants associated with diseases. To increase the power of GWAS, gene-based and pathway-based tests are commonly employed to detect more risk factors. However, the gene- and pathway-based association tests may be biased towards genes or pathways containing a large number of single-nucleotide polymorphisms (SNPs) with small P-values caused by high linkage disequilibrium (LD) correlations. To address such bias, numerous pathway-based methods have been developed. Here we propose a novel method, DGAT-path, to divide all SNPs assigned to genes in each pathway into LD blocks, and to sum the chi-square statistics of LD blocks for assessing the significance of the pathway by permutation tests. The method was proven robust with the type I error rate >1.6 times lower than other methods. Meanwhile, the method displays a higher power and is not biased by the pathway size. The applications to the GWAS summary statistics for schizophrenia and breast cancer indicate that the detected top pathways contain more genes close to associated SNPs than other methods. As a result, the method identified 17 and 12 significant pathways containing 20 and 21 novel associated genes, respectively for two diseases. The method is available online by http://sparks-lab.org/server/DGAT-path .

The mitochondrial genome of the phytopathogenic basidiomycete Moniliophthora perniciosa is 109 kb in size and contains a stable integrated plasmid.

PubMed

Formighieri, Eduardo F; Tiburcio, Ricardo A; Armas, Eduardo D; Medrano, Francisco J; Shimo, Hugo; Carels, Nicolas; Góes-Neto, Aristóteles; Cotomacci, Carolina; Carazzolle, Marcelo F; Sardinha-Pinto, Naiara; Thomazella, Daniela P T; Rincones, Johana; Digiampietri, Luciano; Carraro, Dirce M; Azeredo-Espin, Ana M; Reis, Sérgio F; Deckmann, Ana C; Gramacho, Karina; Gonçalves, Marilda S; Moura Neto, José P; Barbosa, Luciana V; Meinhardt, Lyndel W; Cascardo, Júlio C M; Pereira, Gonçalo A G

2008-10-01

We present here the sequence of the mitochondrial genome of the basidiomycete phytopathogenic hemibiotrophic fungus Moniliophthora perniciosa, causal agent of the Witches' Broom Disease in Theobroma cacao. The DNA is a circular molecule of 109,103 base pairs, with 31.9% GC, and is the largest sequenced so far. This size is due essentially to the presence of numerous non-conserved hypothetical ORFs. It contains the 14 genes coding for proteins involved in the oxidative phosphorylation, the two rRNA genes, one ORF coding for a ribosomal protein (rps3), and a set of 26 tRNA genes that recognize codons for all amino acids. Seven homing endonucleases are located inside introns. Except atp8, all conserved known genes are in the same orientation. Phylogenetic analysis based on the cox genes agrees with the commonly accepted fungal taxonomy. An uncommon feature of this mitochondrial genome is the presence of a region that contains a set of four, relatively small, nested, inverted repeats enclosing two genes coding for polymerases with an invertron-type structure and three conserved hypothetical genes interpreted as the stable integration of a mitochondrial linear plasmid. The integration of this plasmid seems to be a recent evolutionary event that could have implications in fungal biology. This sequence is available under GenBank accession number AY376688.

Importance of benthic prey for fishes in coral reef-associated sediments

USGS Publications Warehouse

DeFelice, R.C.; Parrish, J.D.

2003-01-01

The importance of open, sandy substrate adjacent to coral reefs as habitat and a food source for fishes has been little studied in most shallow tropical waters in the Pacific, including Hawai'i. In this study, in Hanalei Bay, Hiwai'i, we identified and quantified the major invertebrate fauna (larger than 0.5 mm) in the well-characterized sands adjoining the shallow fringing reefs. Concurrently, we identified the fish species that seemed to make substantial use of these sand habitats, estimated their density there, sampled their gut contents to examine trophic links with the sand habitat, and made other observations and collections to determine the times, locations, and types of activity there. A variety of (mostly small) polychaeres were dominant in the sediments at most sampling stations, along with many small crustaceans (e.g., amphipods, isopods, ostracods, and small shrimps) and fair numbers of mollusks (especially bivalves) and small echinoids. Fish guts examined contained ???77% of the total number of benthic taxa collected, including nearly all those just listed. However, fish consumption was selective, and the larger shrimps, crabs, and small cryptic fishes were dominant in the diets of most of the numerous predator taxa. Diets of benthic-feeding fishes showed relatively low specific overlap. The fish fauna in this area included substrate-indifferent pelagics, species with various degrees of reef relatedness, reef-restricted species, and (at the other extreme) permanent cryptic sand dwellers. Data on occurrence and movements of fishes indicated that a band of sandy substrate several tens of meters wide next to the reef was an active area for fishes, and activity was considerably different at different times of day and for fish of different ages. These results imply an important trophic role for the benthos in these near-reef habitats in support of reef-associated fishes.

Implicit Space-Time Conservation Element and Solution Element Schemes

NASA Technical Reports Server (NTRS)

Chang, Sin-Chung; Himansu, Ananda; Wang, Xiao-Yen

1999-01-01

Artificial numerical dissipation is in important issue in large Reynolds number computations. In such computations, the artificial dissipation inherent in traditional numerical schemes can overwhelm the physical dissipation and yield inaccurate results on meshes of practical size. In the present work, the space-time conservation element and solution element method is used to construct new and accurate implicit numerical schemes such that artificial numerical dissipation will not overwhelm physical dissipation. Specifically, these schemes have the property that numerical dissipation vanishes when the physical viscosity goes to zero. These new schemes therefore accurately model the physical dissipation even when it is extremely small. The new schemes presented are two highly accurate implicit solvers for a convection-diffusion equation. The two schemes become identical in the pure convection case, and in the pure diffusion case. The implicit schemes are applicable over the whole Reynolds number range, from purely diffusive equations to convection-dominated equations with very small viscosity. The stability and consistency of the schemes are analysed, and some numerical results are presented. It is shown that, in the inviscid case, the new schemes become explicit and their amplification factors are identical to those of the Leapfrog scheme. On the other hand, in the pure diffusion case, their principal amplification factor becomes the amplification factor of the Crank-Nicolson scheme.

The foetal pig pineal gland is richly innervated by nerve fibres containing catecholamine-synthesizing enzymes, neuropeptide Y (NPY) and C-terminal flanking peptide of NPY, but it does not secrete melatonin.

PubMed

Bulc, Michał; Lewczuk, Bogdan; Prusik, Magdalena; Całka, Jarosław

2013-05-01

Innervation of the mammalian pineal gland during prenatal development is poorly recognized. Therefore, immunofluorescence studies of the pineals of 70- and 90-day-old foetuses of the domestic pig were performed using antibodies against tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DβH), neuropeptide Y (NPY) and C-terminal flanking peptide of NPY (CPON). The investigated glands were supplied by numerous nerve fibres containing TH and DβH. The density of these fibres was higher in the distal and middle parts of the gland than in the proximal one. NPY and CPON were identified in the majority of DβH-positive fibres as well as in a small population of DβH-negative fibres localized mainly in the proximal part of the pineal. The immunoreactive fibres were more numerous in 90-day-old foetuses than in 70-day-old ones. The effect of norepinephrine on melatonin secretion by the foetal pineals in the short-term organ culture was studied to determine the role of DβH-positive fibres during prenatal life. For the same purpose melatonin was measured in the blood in the umbilical cords and in the jugular vein of the mother. The pineals of both groups of foetuses did not secrete melatonin in the organ culture, independently of the presence or absence of norepinephrine in the medium. Melatonin concentrations in the blood in the umbilical cords of foetuses from the same litter and in the jugular vein of their mother were similar. The presence of adrenergic nerve fibres in the pig pineal during gestation does not seem to be associated with the control of melatonin secretion.

Guiding healthier food choice: systematic comparison of four front-of-pack labelling systems and their effect on judgements of product healthiness.

PubMed

Hodgkins, Charo E; Raats, Monique M; Fife-Schaw, Chris; Peacock, Matthew; Gröppel-Klein, Andrea; Koenigstorfer, Joerg; Wasowicz, Grazyna; Stysko-Kunkowska, Malgorzata; Gulcan, Yaprak; Kustepeli, Yesim; Gibbs, Michelle; Shepherd, Richard; Grunert, Klaus G

2015-05-28

Different front-of-pack (FOP) labelling systems have been developed in Europe by industry and organisations concerned with health promotion. A study (n 2068) was performed to establish the extent to which inclusion of the most prevalent FOP systems--guideline daily amounts (GDA), traffic lights (TL), GDA+TL hybrid (HYB) and health logos (HL)--impact consumer perceptions of healthiness over and above the provision of a FOP basic label (BL) containing numerical nutritional information alone. The design included within- and between-subjects factors. The within-subjects factors were: food (pizzas, yogurts and biscuits), healthiness of the food (high health, medium health and low health) and the repeated measurements under BL and test FOP label conditions. The between-subjects factors were: the system (GDA, TL, GDA+TL hybrid, HL), portion size (typical portion size and a 50% reduction of a typical portion) and country (the UK, Germany, Poland and Turkey). Although the FOP systems tested did result in small improvements for objective understanding under some conditions, there was little difference between the provision of an FOP label containing basic numerical nutritional information alone or between the various systems. Thus, any structured and legible presentation of key nutrient and energy information on the FOP label is sufficient to enable consumers to detect a healthier alternative within a food category when provided with foods that have distinctly different levels of healthiness. Future research should focus on developing greater understanding of the psychological and contextual factors that impact motivation and the opportunity to use the various FOP systems in real-world shopping settings.

Impact of bacterial ice nucleating particles on weather predicted by a numerical weather prediction model

NASA Astrophysics Data System (ADS)

Sahyoun, Maher; Korsholm, Ulrik S.; Sørensen, Jens H.; Šantl-Temkiv, Tina; Finster, Kai; Gosewinkel, Ulrich; Nielsen, Niels W.

2017-12-01

Bacterial ice-nucleating particles (INP) have the ability to facilitate ice nucleation from super-cooled cloud droplets at temperatures just below the melting point. Bacterial INP have been detected in cloud water, precipitation, and dry air, hence they may have an impact on weather and climate. In modeling studies, the potential impact of bacteria on ice nucleation and precipitation formation on global scale is still uncertain due to their small concentration compared to other types of INP, i.e. dust. Those earlier studies did not account for the yet undetected high concentration of nanoscale fragments of bacterial INP, which may be found free or attached to soil dust in the atmosphere. In this study, we investigate the sensitivity of modeled cloud ice, precipitation and global solar radiation in different weather scenarios to changes in the fraction of cloud droplets containing bacterial INP, regardless of their size. For this purpose, a module that calculates the probability of ice nucleation as a function of ice nucleation rate and bacterial INP fraction was developed and implemented in a numerical weather prediction model. The threshold value for the fraction of cloud droplets containing bacterial INP needed to produce a 1% increase in cloud ice was determined at 10-5 to 10-4. We also found that increasing this fraction causes a perturbation in the forecast, leading to significant differences in cloud ice and smaller differences in convective and total precipitation and in net solar radiation reaching the surface. These effects were most pronounced in local convective events. Our results show that bacterial INP can be considered as a trigger factor for precipitation, but not an enhancement factor.

Scanning and transmission electron microscopy and X-ray analysisof leaf salt glands of Limoniastrum guyonianum Boiss. under NaCl salinity.

PubMed

Zouhaier, Barhoumi; Abdallah, Atia; Najla, Trabelsi; Wahbi, Djebali; Wided, Chaïbi; Aouatef, Ben Ammar; Chedly, Abdelly; Abderazzak, Smaoui

2015-11-01

Leaf salt glands of Limoniastrum guyonianum were examined by scanning and transmission electron microscopes and energy dispersive X-ray analysis (EDAX) system, after growing for three months on sandy soil with or without 300 mM NaCl. Results showed that salt glands were irregularly scattered on both leaf sides and sunk under the epidermal level. Salt excretion occurred in both conditions and is mainly composed of calcium and magnesium in control plants, and essentially sodium and chloride in plants subjected to salt treatment. A salt gland is comprised of collecting, accumulating, and central compartments, and is made up of total thirty-two cells. The collecting cells were characterized by large central vacuoles. Accumulating cells contain numerous, large, and unshaped vacuoles and rudimentary chloroplasts. The central compartment was comprised of four basal cells and each one is surmounted by an apical cell. The basal cells are granulated, containing large nucleus, numerous mitochondria, endoplasmic reticulum, ribosomes, polyribosomes, and small vacuoles or vesicles. Equally, the apical cells are rich in organelles. Application of 300 mM NaCl to the culture medium increased vacuoles number and size, and organelles density especially the mitochondria which suggests energy requirement for ions transport. The reduction in size and number of vacuoles toward the interior of salt glands of treated plants and the fusion of the smallest ones with the plasma membrane substantiate the implication of such vacuoles in salt excretion process. The current study which is the first report on L. guyonianum salt gland has provided an in-depth understanding on structure-function relationship in the multicellular salt glands. Copyright © 2015 Elsevier Ltd. All rights reserved.

Small-scale multi-axial hybrid simulation of a shear-critical reinforced concrete frame

NASA Astrophysics Data System (ADS)

Sadeghian, Vahid; Kwon, Oh-Sung; Vecchio, Frank

2017-10-01

This study presents a numerical multi-scale simulation framework which is extended to accommodate hybrid simulation (numerical-experimental integration). The framework is enhanced with a standardized data exchange format and connected to a generalized controller interface program which facilitates communication with various types of laboratory equipment and testing configurations. A small-scale experimental program was conducted using a six degree-of-freedom hydraulic testing equipment to verify the proposed framework and provide additional data for small-scale testing of shearcritical reinforced concrete structures. The specimens were tested in a multi-axial hybrid simulation manner under a reversed cyclic loading condition simulating earthquake forces. The physical models were 1/3.23-scale representations of a beam and two columns. A mixed-type modelling technique was employed to analyze the remainder of the structures. The hybrid simulation results were compared against those obtained from a large-scale test and finite element analyses. The study found that if precautions are taken in preparing model materials and if the shear-related mechanisms are accurately considered in the numerical model, small-scale hybrid simulations can adequately simulate the behaviour of shear-critical structures. Although the findings of the study are promising, to draw general conclusions additional test data are required.

Procurement | NREL

Science.gov Websites

Procurement Procurement The National Renewable Energy Laboratory (NREL) offers numerous procurement source of biofuels. Register Your Small Business NREL welcomes small, disadvantaged, HUBzone, veteran -owned, and women-owned business vendors and subcontractors. Register today

The "Big Box"

ERIC Educational Resources Information Center

Gran, Warren; Krudwig, Kevin

2007-01-01

The small-schools movement has revolutionized educational concepts, design and construction. By reconfiguring large high schools into smaller learning academies, districts believe they can educate students more effectively. However, planners face numerous challenges in creating or renovating small schools, especially in urban environments where…

Electron microscopic immunocytochemical study of somatostatin neurons in the periventricular nucleus of the rat hypothalamus with special reference to their relationships with homologous neuronal processes.

PubMed

Alonso, G; Tapia-Arancibia, L; Assenmacher, I

1985-10-01

The neurons containing somatostatin in the rat periventricular nucleus were studied by using a modified electron microscopic immunocytochemical technique that improves both the penetration of immunoreagents into unembedded immunostained tissues and the preservation of ultrastructural morphology. Inside perikarya and dendrites, immunostaining was not only associated with neurosecretory granules but also with ribosomes and saccules of the cis face of the Golgi apparatus. In the axonal profiles found in this region the labeling was observed both on neurosecretory granule cores and on the limiting membrane of small synaptic-like vesicles. Throughout the periventricular nucleus, both non-synaptic and synaptic relationships were shown between labeled neurons. Non-synaptic relationships mainly consisted of direct apposition of the membranes of neighboring neurons by dendrosomatic, somasomatic or dendrodendritic contacts. These labeled perikarya and dendrites were also synaptically contacted by labeled axonal endings containing numerous aggregated synaptic-like vesicles. The physiological significance of the synaptic and non-synaptic relationships between somatostatinergic neurons is discussed in terms of possible synchronization between homologous neurons of the somatostatin neuroendocrine system and control of these neurons by a central ultra-short loop feedback mechanism.

A tubulidentate suiform lineage (Tayassuidae, Mammalia) from the Early Miocene of Spain

NASA Astrophysics Data System (ADS)

Pickford, Martin; Morales, Jorge

1998-08-01

Small suiform artiodactyls from Moheda, Loranca and Corcolés, Spain, possess tubulidentate microstructure in their cheek tooth roots. The oldest specimens from Moheda (MN 2a) have a few scattered tubules near the apices of the molar roots, those from Loranca (MN 2b) have numerous tubules of various diameters in contact with each other, but oriented at various angles, while specimens from Corcolés (MN 4) are completely tubulidentate with well developed, sub-parallel tubules of sub-equal diameter running the entire length of the roots. The same series of fossils shows that with the passage of geological time the roots of this tayassuid lineage became more hypsorhizic and fusion of the roots increased, while the crowns of the teeth became simpler and thinner enamelled. Selection in this lineage was therefore focused upon increasing the longevity and wear resistance of the roots, while the role of the crowns of the teeth in mastication was de-emphasised. It is hypothesised that, as in Tubulidentata and Edentata, this suiform lineage was ingesting food items which contained significant quantities of adhérant earth. Whether the diet also contained ants and termites is not known.

Membrane vesicles in sea water: heterogeneous DNA content and implications for viral abundance estimates

PubMed Central

Biller, Steven J; McDaniel, Lauren D; Breitbart, Mya; Rogers, Everett; Paul, John H; Chisholm, Sallie W

2017-01-01

Diverse microbes release membrane-bound extracellular vesicles from their outer surfaces into the surrounding environment. Vesicles are found in numerous habitats including the oceans, where they likely have a variety of functional roles in microbial ecosystems. Extracellular vesicles are known to contain a range of biomolecules including DNA, but the frequency with which DNA is packaged in vesicles is unknown. Here, we examine the quantity and distribution of DNA associated with vesicles released from five different bacteria. The average quantity of double-stranded DNA and size distribution of DNA fragments released within vesicles varies among different taxa. Although some vesicles contain sufficient DNA to be visible following staining with the SYBR fluorescent DNA dyes typically used to enumerate viruses, this represents only a small proportion (<0.01–1%) of vesicles. Thus DNA is packaged heterogeneously within vesicle populations, and it appears that vesicles are likely to be a minor component of SYBR-visible particles in natural sea water compared with viruses. Consistent with this hypothesis, chloroform treatment of coastal and offshore seawater samples reveals that vesicles increase epifluorescence-based particle (viral) counts by less than an order of magnitude and their impact is variable in space and time. PMID:27824343

Characterization of subpopulations and immune-related parameters of hemocytes in the green-lipped mussel Perna viridis.

PubMed

Wang, Youji; Hu, Menghong; Chiang, M W L; Shin, P K S; Cheung, S G

2012-03-01

The green-lipped mussel Perna viridis is distributed widely in the estuarine and coastal areas of the Indo-Pacific region and extensively cultured as an inexpensive protein source. Morphology and immunological activities of hemocytes of P. viridis were investigated using flow cytometry and light and electron microscopy. Three major types of hemocytes were identified in the hemolymph, including dense-granulocyte, semi-granulocyte (small and large size) and hyalinocyte. Other hemocytes, which occurred in low numbers, included granulocytes with different electron-dense/lucent granules and hemoblast-like cells. Based on flow cytometry, two subpopulations were identified. Granulocytes were larger cells, and the more abundant, containing numerous granules in the cytoplasm, and hyalinocytes were the smaller and less abundant with the fewest granules. Flow cytometry revealed that the granulocytes were more active in cell phagocytosis, contained the higher lysosomal content, and showed higher esterase activity and reactive oxygen species (ROS) generation compared with hyalinocytes. Immune functions assessed by the flow cytometry indicated that the granulocytes were the main hemocytes involved in the cellular defence in P. viridis. Copyright © 2011. Published by Elsevier Ltd.

Variational Methods For Sloshing Problems With Surface Tension

NASA Astrophysics Data System (ADS)

Tan, Chee Han; Carlson, Max; Hohenegger, Christel; Osting, Braxton

2016-11-01

We consider the sloshing problem for an incompressible, inviscid, irrotational fluid in a container, including effects due to surface tension on the free surface. We restrict ourselves to a constant contact angle and we seek time-harmonic solutions of the linearized problem, which describes the time-evolution of the fluid due to a small initial disturbance of the surface at rest. As opposed to the zero surface tension case, where the problem reduces to a partial differential equation for the velocity potential, we obtain a coupled system for the velocity potential and the free surface displacement. We derive a new variational formulation of the coupled problem and establish the existence of solutions using the direct method from the Calculus of Variations. In the limit of zero surface tension, we recover the variational formulation of the classical Steklov eigenvalue problem, as derived by B. A. Troesch. For the particular case of an axially symmetric container, we propose a finite element numerical method for computing the sloshing modes of the coupled system. The scheme is implemented in FEniCS and we obtain a qualitative description of the effect of surface tension on the sloshing modes.

Self-mixing magma in the Ruiz Peak rhyodacite (New Mexico, USA): A mechanism explaining the formation of long period polytypes of mica

NASA Astrophysics Data System (ADS)

Pignatelli, I.; Faure, F.; Mosser-Ruck, R.

2016-12-01

The rhyodacite of Ruiz Peak Volcano (New Mexico, USA) is an exceptional rock because it contains both long period and short period polytypes of mica. Our petrographic study shows that this rhyodacite is characterized by numerous disequilibrium textures of phenocrysts (mica, amphibole, clinopyroxene, olivine and plagioclase) contained within both dark-grey and reddish coloured groundmass. The presence of two groundmasses, as well as of disequilibrium textures (reaction rims, resorption, dendritic, skeletal morphologies, etc.) suggests a complex magmatic history. These two types of groundmass are not due to a mixing of magmas but result from a degassing process during the magma ascent in the conduit. The disequilibrium textures are interpreted to be the result of small, short-lived convection cells in the magmatic chamber, which may allow crystal-crystal, crystal-spiral and spiral-spiral interactions to occur, leading to the formation of long period polytypes of mica. For the first time, the relationships between the crystallographic features of mica and the host-rock formation are underlined in this study. It follows that long period polytypes of mica can be considered markers of the complex history of magmas.

On the interaction of small and large eddies in two dimensional turbulent flows

NASA Technical Reports Server (NTRS)

Foias, C.; ate work.

1987-01-01

Some results concerning the interaction of small and large eddies to two dimensional turbulent flows are presented. It is shown that the amplitude of small structures decays exponentially to a small value, and from this is inferred a simplified interaction law of small and large eddies. Beside their intrinsic interest for the understanding of the physics of turbulence, these results lead to new numerical schemes to be studied in a separate work.

IslandFAST: A Semi-numerical Tool for Simulating the Late Epoch of Reionization

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

Xu, Yidong; Chen, Xuelei; Yue, Bin

2017-08-01

We present the algorithm and main results of our semi-numerical simulation, islandFAST, which was developed from 21cmFAST and designed for the late stage of reionization. The islandFAST simulation predicts the evolution and size distribution of the large-scale underdense neutral regions (neutral islands), and we find that the late Epoch of Reionization proceeds very fast, showing a characteristic scale of the neutral islands at each redshift. Using islandFAST, we compare the impact of two types of absorption systems, i.e., the large-scale underdense neutral islands versus small-scale overdense absorbers, in regulating the reionization process. The neutral islands dominate the morphology of themore » ionization field, while the small-scale absorbers dominate the mean-free path of ionizing photons, and also delay and prolong the reionization process. With our semi-numerical simulation, the evolution of the ionizing background can be derived self-consistently given a model for the small absorbers. The hydrogen ionization rate of the ionizing background is reduced by an order of magnitude in the presence of dense absorbers.« less

Weighted small subdomain filtering technology

NASA Astrophysics Data System (ADS)

Tai, Zhenhua; Zhang, Fengxu; Zhang, Fengqin; Zhang, Xingzhou; Hao, Mengcheng

2017-09-01

A high-resolution method to define the horizontal edges of gravity sources is presented by improving the three-directional small subdomain filtering (TDSSF). This proposed method is the weighted small subdomain filtering (WSSF). The WSSF uses a numerical difference instead of the phase conversion in the TDSSF to reduce the computational complexity. To make the WSSF more insensitive to noise, the numerical difference is combined with the average algorithm. Unlike the TDSSF, the WSSF uses a weighted sum to integrate the numerical difference results along four directions into one contour, for making its interpretation more convenient and accurate. The locations of tightened gradient belts are used to define the edges of sources in the WSSF result. This proposed method is tested on synthetic data. The test results show that the WSSF provides the horizontal edges of sources more clearly and correctly, even if the sources are interfered with one another and the data is corrupted with random noise. Finally, the WSSF and two other known methods are applied to a real data respectively. The detected edges by the WSSF are sharper and more accurate.

The chemistry and anticarcinogenic mechanisms of glycoalkaloids produced by eggplants, potatoes, and tomatoes

USDA-ARS?s Scientific Manuscript database

Inhibition of cancer can occur via apoptosis, a genetically directed process of cell self-destruction that involves numerous biomarkers and signaling pathways. Glycoalkaloids are nitrogen-containing secondary plant metabolites found in numerous Solanaceous plants including eggplants, potatoes, and ...

Numerical Simulation of Oblique Impacts: Impact Melt and Transient Cavity Size

NASA Technical Reports Server (NTRS)

Artemieva, N. A.; Ivanov, B. A.

2001-01-01

We present 3D hydrocode numerical modeling for oblique impacts (i) to estimate the melt production and (ii) to trace the evolution of the transient cavity shape till the crater collapse. Additional information is contained in the original extended abstract.

Large Scale Survey Data in Career Development Research

ERIC Educational Resources Information Center

Diemer, Matthew A.

2008-01-01

Large scale survey datasets have been underutilized but offer numerous advantages for career development scholars, as they contain numerous career development constructs with large and diverse samples that are followed longitudinally. Constructs such as work salience, vocational expectations, educational expectations, work satisfaction, and…

Multiresolution representation and numerical algorithms: A brief review

NASA Technical Reports Server (NTRS)

Harten, Amiram

1994-01-01

In this paper we review recent developments in techniques to represent data in terms of its local scale components. These techniques enable us to obtain data compression by eliminating scale-coefficients which are sufficiently small. This capability for data compression can be used to reduce the cost of many numerical solution algorithms by either applying it to the numerical solution operator in order to get an approximate sparse representation, or by applying it to the numerical solution itself in order to reduce the number of quantities that need to be computed.

Stress and Sealing Performance Analysis of Containment Vessel

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

WU, TSU-TE

2005-05-24

This paper presents a numerical technique for analyzing the containment vessel subjected to the combined loading of closure-bolt torque and internal pressure. The detailed stress distributions in the O-rings generated by both the torque load and the internal pressure can be evaluated by using this method. Consequently, the sealing performance of the O-rings can be determined. The material of the O-rings can be represented by any available constitutive equation for hyperelastic material. In the numerical calculation of this paper, the form of the Mooney-Rivlin strain energy potential is used. The technique treats both the preloading process of bolt tightening andmore » the application of internal pressure as slow dynamic loads. Consequently, the problem can be evaluated using explicit numerical integration scheme.« less

Distribution and ultrastructure of dopaminergic neurons in the dorsal motor nucleus of the vagus projecting to the stomach of the rat.

PubMed

Hayakawa, Tetsu; Takanaga, Akinori; Tanaka, Koichi; Maeda, Seishi; Seki, Makoto

2004-04-23

Almost all parasympathetic preganglionic motor neurons contain acetylcholine, whereas quite a few motor neurons in the dorsal motor nucleus of the vagus (DMV) contain dopamine. We determined the distribution and ultrastructure of these dopaminergic neurons with double-labeling immunohistochemistry for tyrosine hydroxylase (TH) and the retrograde tracer cholera toxin subunit b (CTb) following its injection into the stomach. A few TH-immunoreactive (TH-ir) neurons were found in the rostral half of the DMV, while a moderate number of these neurons were found in the caudal half. Most of the TH-ir neurons (78.4%) were double-labeled for CTb in the half of the DMV caudal to the area postrema, but only a few TH-ir neurons (5.5%) were double-labeled in the rostral half. About 20% of gastric motor neurons showed TH-immunoreactivity in the caudal half of the DMV, but only 0.3% were TH-ir in the rostral half. In all gastric motor neurons, 8.1% were double-labeled for TH. The ultrastructure of the TH-ir neurons in the caudal DMV was determined with immuno-gold-silver labeling. The TH-ir neurons were small (20.4 x 12.4 microm), round or oval, and contained numerous mitochondria, many free ribosomes, several Golgi apparatuses, a round nucleus and a few Nissl bodies. The average number of axosomatic terminals per section was 4.0. More than half of them contained round synaptic vesicles and made asymmetric synaptic contacts (Gray's type I). Most of the axodendritic terminals contacting TH-ir dendrites were Gray's type I (90%), but a few contained pleomorphic vesicles and made symmetric synaptic contacts (Gray's type II).

At Birth, Humans Associate "Few" with Left and "Many" with Right.

PubMed

de Hevia, Maria Dolores; Veggiotti, Ludovica; Streri, Arlette; Bonn, Cory D

2017-12-18

Humans use spatial representations to structure abstract concepts [1]. One of the most well-known examples is the "mental number line"-the propensity to imagine numbers oriented in space [2, 3]. Human infants [4, 5], children [6, 7], adults [8], and nonhuman animals [9, 10] associate small numbers with the left side of space and large numbers with the right. In humans, cultural artifacts, such as the direction of reading and writing, modulate the directionality of this representation, with right-to-left reading cultures associating small numbers with right and large numbers with left [11], whereas the opposite association permeates left-to-right reading cultures [8]. Number-space mapping plays a central role in human mathematical concepts [12], but its origins remain unclear: is it the result of an innate bias or does it develop after birth? Infant humans are passively exposed to a spatially coded environment, so experience and culture could underlie the mental number line. To rule out this possibility, we tested neonates' responses to small or large auditory quantities paired with geometric figures presented on either the left or right sides of the screen. We show that 0- to 3-day-old neonates associate a small quantity with the left and a large quantity with the right when the multidimensional stimulus contains discrete numerical information, providing evidence that representations of number are associated to an oriented space at the start of postnatal life, prior to experience with language, culture, or with culture-specific biases. Copyright © 2017 Elsevier Ltd. All rights reserved.

The terminal area simulation system. Volume 2: Verification cases

NASA Technical Reports Server (NTRS)

Proctor, F. H.

1987-01-01

The numerical simulation of five case studies are presented and are compared with available data in order to verify the three-dimensional version of the Terminal Area Simulation System (TASS). A spectrum of convective storm types are selected for the case studies. Included are: a High-Plains supercell hailstorm, a small and relatively short-lived High-Plains cumulonimbus, a convective storm which produced the 2 August 1985 DFW microburst, a South Florida convective complex, and a tornadic Oklahoma thunderstorm. For each of the cases the model results compared reasonably well with observed data. In the simulations of the supercell storms many of their characteristic features were modeled, such as the hook echo, BWER, mesocyclone, gust fronts, giant persistent updraft, wall cloud, flanking-line towers, anvil and radar reflectivity overhang, and rightward veering in the storm propagation. In the simulation of the tornadic storm a horseshoe-shaped updraft configuration and cyclic changes in storm intensity and structure were noted. The simulation of the DFW microburst agreed remarkably well with sparse observed data. The simulated outflow rapidly expanded in a nearly symmetrical pattern and was associated with a ringvortex. A South Florida convective complex was simulated and contained updrafts and downdrafts in the form of discrete bubbles. The numerical simulations, in all cases, always remained stable and bounded with no anomalous trends.

Implications of a fossil stickleback assemblage for Darwinian gradualism.

PubMed

Bell, M A

2009-11-01

Darwin postulated that a complete fossil record would contain numerous gradual transitions between ancestral and descendant species, but 150 years after publication of The Origin of Species, few such transitions have materialized. The fossil stickleback Gasterosteus doryssus and the deposit in which it occurs provide excellent conditions to detect such transitions. Abundant, well-preserved fossils occur in a stratigraphic setting with fine temporal resolution. The paleoecology of G. doryssus resembles the ecology of modern lakes that harbour the phenotypically similar three-spined stickleback Gasterosteus aculeatus. Gasterosteus aculeatus are primitively highly armoured, but G. doryssus comprised two contemporaneous biological species with relatively weak armour, including a near-shore, benthic feeder (benthic) and an offshore planktivore (limnetic). The benthic species expanded its range into the limnetic zone of the lake, where it apparently switched to planktivory and evolved reduced armour within c. 5000 years in response to directional selection. Although gradual evolution of mean phenotypes occurred, a single major gene caused much of evolutionary change of the pelvic skeleton. Thus, Darwin's expectation that transitions between species in the fossil record would be gradual was met at a fine time scale, but for pelvic structure, a well-studied trait, his expectation that gradual change would depend entirely on numerous, small, heritable differences among individuals was incorrect.

Numerical Study of Mixed Convective Peristaltic Flow through Vertical Tube with Heat Generation for Moderate Reynolds and Wave Numbers

NASA Astrophysics Data System (ADS)

Javed, Tariq; Ahmed, B.; Sajid, M.

2018-04-01

The current study focuses on the numerical investigation of the mixed convective peristaltic mechanism through a vertical tube for non-zero Reynolds and wave number. In the set of constitutional equations, energy equation contains the term representing heat generation parameter. The problem is formulated by dropping the assumption of lubrication theory that turns the model mathematically into a system of the nonlinear partial differential equations. The results of the long wavelength in a creeping flow are deduced from the present analysis. Thus, the current study explores the neglected features of peristaltic heat flow in the mixed convective model by considering moderate values of Reynolds and wave numbers. The finite element based on Galerkin’s weighted residual scheme is applied to solve the governing equations. The computed solution is presented in the form of contours of streamlines and isothermal lines, velocity and temperature profiles for variation of different involved parameters. The investigation shows that the strength of circulation for stream function increases by increasing the wave number and Reynolds number. Symmetric isotherms are reported for small values of time-mean flow. Linear behavior of pressure is noticed by vanishing inertial forces while the increase in pressure is observed by amplifying the Reynolds number.

Evolution of the Orszag-Tang vortex system in a compressible medium. I - Initial average subsonic flow

NASA Technical Reports Server (NTRS)

Dahlburg, R. B.; Picone, J. M.

1989-01-01

The results of fully compressible, Fourier collocation, numerical simulations of the Orszag-Tang vortex system are presented. The initial conditions for this system consist of a nonrandom, periodic field in which the magnetic and velocity field contain X points but differ in modal structure along one spatial direction. The velocity field is initially solenoidal, with the total initial pressure field consisting of the superposition of the appropriate incompressible pressure distribution upon a flat pressure field corresponding to the initial, average Mach number of the flow. In these numerical simulations, this initial Mach number is varied from 0.2-0.6. These values correspond to average plasma beta values ranging from 30.0 to 3.3, respectively. It is found that compressible effects develop within one or two Alfven transit times, as manifested in the spectra of compressible quantities such as the mass density and the nonsolenoidal flow field. These effects include (1) a retardation of growth of correlation between the magnetic field and the velocity field, (2) the emergence of compressible small-scale structure such as massive jets, and (3) bifurcation of eddies in the compressible flow field. Differences between the incompressible and compressible results tend to increase with increasing initial average Mach number.

Numerical investigations in three-dimensional internal flows

NASA Astrophysics Data System (ADS)

Rose, William C.

1988-08-01

An investigation into the use of computational fluid dynamics (CFD) was performed to examine the expected heat transfer rates that will occur within the NASA-Ames 100 megawatt arc heater nozzle. This nozzle was tentatively designed and identified to provide research for a directly connected combustion experiment specifically related to the National Aerospace Plane Program (NASP) aircraft, and is expected to simulate the flow field entering the combustor section. It was found that extremely fine grids, that is very small mesh spacing near the wall, are required to accurately model the heat transfer process and, in fact, must contain a point within the laminar sublayer if results are to be taken directly from a numerical simulation code. In the present study, an alternative to this very fine mesh and its attendant increase in computational time was invoked and is based on a wall-function method. It was shown that solutions could be obtained that give accurate indications of surface heat transfer rate throughout the nozzle in approximately 1/100 of the computer time required to do the simulation directly without the use of the wall-function implementation. Finally, a maximum heating value in the throat region of the proposed slit nozzle for the 100 megawatt arc heater was shown to be approximately 6 MW per square meter.

Evolution of the Orszag--Tang vortex system in a compressible medium. I. Initial average subsonic flow

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

Dahlburg, R.B.; Picone, J.M.

In this paper the results of fully compressible, Fourier collocation, numerical simulations of the Orszag--Tang vortex system are presented. The initial conditions for this system consist of a nonrandom, periodic field in which the magnetic and velocity field contain X points but differ in modal structure along one spatial direction. The velocity field is initially solenoidal, with the total initial pressure field consisting of the superposition of the appropriate incompressible pressure distribution upon a flat pressure field corresponding to the initial, average Mach number of the flow. In these numerical simulations, this initial Mach number is varied from 0.2--0.6. Thesemore » values correspond to average plasma beta values ranging from 30.0 to 3.3, respectively. It is found that compressible effects develop within one or two Alfven transit times, as manifested in the spectra of compressible quantities such as the mass density and the nonsolenoidal flow field. These effects include (1) a retardation of growth of correlation between the magnetic field and the velocity field, (2) the emergence of compressible small-scale structure such as massive jets, and (3) bifurcation of eddies in the compressible flow field. Differences between the incompressible and compressible results tend to increase with increasing initial average Mach number.« less

Geologic and aeromagnetic maps of the Fossil Ridge area and vicinity, Gunnison County, Colorado

USGS Publications Warehouse

DeWitt, Ed; Zech, R.S.; Chase, C.G.; Zartman, R.E.; Kucks, R.P.; Bartelson, Bruce; Rosenlund, G.C.; Earley, Drummond

2002-01-01

This data set includes a GIS geologic map database of an Early Proterozoic metavolcanic and metasedimentary terrane extensively intruded by Early and Middle Proterozoic granitic plutons. Laramide to Tertiary deformation and intrusion of felsic plutons have created numerous small mineral deposits that are described in the tables and are shown on the figures in the accompanying text pamphlet. Also included in the pamphlet are numerous chemical analyses of igneous and meta-igneous bodies of all ages in tables and in summary geochemical diagrams. The text pamphlet also contains a detailed description of map units and discussions of the aeromagnetic survey, igneous and metmorphic rocks, and mineral deposits. The printed map sheet and browse graphic pdf file include the aeromagnetic map of the study area, as well as figures and photographs. Purpose: This GIS geologic map database is provided to facilitate the presentation and analysis of earth-science data for this region of Colorado. This digital map database may be displayed at any scale or projection. However, the geologic data in this coverage are not intended for use at a scale other than 1:30,000. Supplemental useful data accompanying the database are extensive geochemical and mineral deposits data, as well as an aeromagnetic map.

Sulfur "Bergs" and Sulfur Pools: Loki and Tupan Patera on Io

NASA Astrophysics Data System (ADS)

Howell, R. R.; Lopes, R. M.; Landis, C. E.; Allen, D. R.

2012-12-01

Loki and Tupan Patera on Io show numerous features related to the presence of volatiles. There are both striking similarities and distinct differences in the way the volatiles have acted at these two sites. At Loki numerous small bright features, colloquially known as sulfur "bergs", are distributed across the dark patera surface. We map their spatial distribution and spectral properties (Landis et al., this conference) and model sulfur vapor transport processes (Allen et al. this conference) to determine if those bright features are consistent with sulfur fumarole deposits. Alternatively, the "bergs" may represent topographic highs (kipukas) left un-resurfaced by the recurrent activity at Loki. To test this we examine Voyager, Galileo, and New Horizons images to determine if any changes in their spatial distribution have occurred over the 1979 through 2007 period. We also discuss further a statistical analysis of their size and spectral reflectance. Tupan shows an overall morphology similar to Loki, with a central island and one straight margin. It also shows linear features extending across the island. However instead of the dark eastern portion of the patera containing a myriad of small bright features like the Loki "bergs" which avoid the margins, Tupan shows higher albedo deposits concentrated at the margins. And in the higher albedo western portion of Tupan Patera numerous low albedo features can be interpreted as dark silicates erupting or eating through a volatile rich crust. Unlike Loki, these intra-patera features at Tupan clearly have sharply defined edges, indicating surface flow processes rather than possible vapor effects. However both outside the main Tupan Patera walls and on the island there are more diffuse patterns consistent with vapor transport. A detailed comparison of reflectance at violet through very near infrared wavelengths helps elucidate these effects. As also found at Loki, a low violet reflectance indicates that sulfur is abundant on many of the surfaces within the patera. That detailed comparison also helps highlight the vapor effects mentioned above. We discuss the insights into volatile processes gained from a detailed comparison of the Loki and Tupan images, and the implications those have for volcanism on Io.

Error Estimation and Uncertainty Propagation in Computational Fluid Mechanics

NASA Technical Reports Server (NTRS)

Zhu, J. Z.; He, Guowei; Bushnell, Dennis M. (Technical Monitor)

2002-01-01

Numerical simulation has now become an integral part of engineering design process. Critical design decisions are routinely made based on the simulation results and conclusions. Verification and validation of the reliability of the numerical simulation is therefore vitally important in the engineering design processes. We propose to develop theories and methodologies that can automatically provide quantitative information about the reliability of the numerical simulation by estimating numerical approximation error, computational model induced errors and the uncertainties contained in the mathematical models so that the reliability of the numerical simulation can be verified and validated. We also propose to develop and implement methodologies and techniques that can control the error and uncertainty during the numerical simulation so that the reliability of the numerical simulation can be improved.

Effects of Magnetic and Kinetic Helicities on the Growth of Magnetic Fields in Laminar and Turbulent Flows by Helical Fourier Decomposition

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

Linkmann, Moritz; Sahoo, Ganapati; Biferale, Luca

We present a numerical and analytical study of incompressible homogeneous conducting fluids using a helical Fourier representation. We analytically study both small- and large-scale dynamo properties, as well as the inverse cascade of magnetic helicity, in the most general minimal subset of interacting velocity and magnetic fields on a closed Fourier triad. We mainly focus on the dependency of magnetic field growth as a function of the distribution of kinetic and magnetic helicities among the three interacting wavenumbers. By combining direct numerical simulations of the full magnetohydrodynamics equations with the helical Fourier decomposition, we numerically confirm that in the kinematicmore » dynamo regime the system develops a large-scale magnetic helicity with opposite sign compared to the small-scale kinetic helicity, a sort of triad-by-triad α -effect in Fourier space. Concerning the small-scale perturbations, we predict theoretically and confirm numerically that the largest instability is achived for the magnetic component with the same helicity of the flow, in agreement with the Stretch–Twist–Fold mechanism. Vice versa, in the presence of Lorentz feedback on the velocity, we find that the inverse cascade of magnetic helicity is mostly local if magnetic and kinetic helicities have opposite signs, while it is more nonlocal and more intense if they have the same sign, as predicted by the analytical approach. Our analytical and numerical results further demonstrate the potential of the helical Fourier decomposition to elucidate the entangled dynamics of magnetic and kinetic helicities both in fully developed turbulence and in laminar flows.« less

High-numerical-aperture-based virtual point detectors for photoacoustic tomography

NASA Astrophysics Data System (ADS)

Li, Changhui; Wang, Lihong V.

2008-07-01

The focal point of a high-numerical-aperture (NA) ultrasonic transducer can be used as a virtual point detector. This virtual point detector detects omnidirectionally over a wide acceptance angle. It also combines a large active transducer surface and a small effective virtual detector size. Thus the sensitivity is high compared with that of a real point detector, and the aperture effect is small compared with that of a finite size transducer. We present two kinds of high-NA-based virtual point detectors and their successful application in photoacoustic tomography. They can also be applied in other ultrasound-related fields.

QIKAIM, a fast seminumerical algorithm for the generation of minute-of-arc accuracy satellite predictions

NASA Astrophysics Data System (ADS)

Vermeer, M.

1981-07-01

A program was designed to replace AIMLASER for the generation of aiming predictions, to achieve a major saving in computing time, and to keep the program small enough for use even on small systems. An approach was adopted that incorporated the numerical integration of the orbit through a pass, limiting the computation of osculating elements to only one point per pass. The numerical integration method which is fourth order in delta t in the cumulative error after a given time lapse is presented. Algorithms are explained and a flowchart and listing of the program are provided.

Robust recognition of handwritten numerals based on dual cooperative network

NASA Technical Reports Server (NTRS)

Lee, Sukhan; Choi, Yeongwoo

1992-01-01

An approach to robust recognition of handwritten numerals using two operating parallel networks is presented. The first network uses inputs in Cartesian coordinates, and the second network uses the same inputs transformed into polar coordinates. How the proposed approach realizes the robustness to local and global variations of input numerals by handling inputs both in Cartesian coordinates and in its transformed Polar coordinates is described. The required network structures and its learning scheme are discussed. Experimental results show that by tracking only a small number of distinctive features for each teaching numeral in each coordinate, the proposed system can provide robust recognition of handwritten numerals.

Equilibrium stellar systems with spindle singularities

NASA Technical Reports Server (NTRS)

Shapiro, Stuart L.; Teukolsky, Saul A.

1992-01-01

Equilibrium sequences of axisymmetric Newtonian clusters that tend toward singular states are constructed. The distribution functions are chosen to be of the form f = f(E, Jz). The numerical method then determines the density and gravitational potential self-consistently to satisfy Poisson's equation. For the prolate models, spindle singularities arise from the depletion of angular momentum near the symmetry axis. While the resulting density enhancement is confined to the region near the axis, the influence of the spindle extends much further out through its tidal gravitational field. Centrally condensed prolate clusters may contain strong-field regions even though the spindle mass is small and the mean cluster eccentricity is not extreme. While the calculations performed here are entirely Newtonian, the issue of singularities is an important topic in general relativity. Equilibrium solutions for relativistic star clusters can provide a testing ground for exploring this issue. The methods used in this paper for building nonspherical clusters can be extended to relativistic systems.

Nanosomal Docetaxel Lipid Suspension: A Guide to Its Use in Cancer.

PubMed

McKeage, Kate

2017-04-01

Nanosomal docetaxel lipid suspension (NDLS) [DoceAqualip] is a novel formulation of docetaxel approved in India for the treatment of breast cancer, hormone-refractory prostate cancer, locally advanced squamous cell carcinoma of the head and neck, non-small cell lung cancer and advanced gastric adenocarcinoma. The lipid-based delivery system of NDLS eliminates the need for polysorbate 80 and ethanol, which are contained in the conventional docetaxel formulation and are associated with hypersensitivity reactions and infusion-related toxicities. Because of the diminished potential for NDLS to cause hypersensitivity reactions compared with conventional docetaxel, corticosteroid premedication is not required with NDLS. In a randomized trial in patients with pretreated, locally advanced or metastatic breast cancer, the overall response rate was numerically higher with NDLS than with conventional docetaxel, and post-dose adverse events in the NDLS group were considered manageable and most resolved without sequelae, despite the lack of corticosteroid premedication.

Producer gas production of Indonesian biomass in fixed-bed downdraft gasifier as an alternative fuels for internal combustion engines

NASA Astrophysics Data System (ADS)

Simanjuntak, J. P.; Lisyanto; Daryanto, E.; Tambunan, B. H.

2018-03-01

downdraft biomass gasification reactors, coupled with reciprocating internal combustion engines (ICE) are a viable technology for small scale heat and power generation. The direct use of producer gas as fuel subtitution in an ICE could be of great interest since Indonesia has significant land area in different forest types that could be used to produce bioenergy and convert forest materials to bioenergy for use in energy production and the versatility of this engine. This paper will look into the aspect of biomass energie as a contributor to energy mix in Indonesia. This work also contains information gathered from numerous previews study on the downdraft gasifier based on experimental or simulation study on the ability of producer gas as fuels for internal combustion engines aplication. All data will be used to complement the preliminary work on biomass gasification using downdraft to produce producer gas and its application to engines.

Acoustic propagation in a thermally stratified atmosphere

NASA Technical Reports Server (NTRS)

Vanmoorhem, W. K.

1988-01-01

Acoustic propagation in an atmosphere with a specific form of a temperature profile has been investigated by analytical means. The temperature profile used is representative of an actual atmospheric profile and contains three free parameters. Both lapse and inversion cases have been considered. Although ray solutions have been considered, the primary emphasis has been on solutions of the acoustic wave equation with point source where the sound speed varies with height above the ground corresponding to the assumed temperature profile. The method used to obtain the solution of the wave equation is based on Hankel transformation of the wave equation, approximate solution of the transformed equation for wavelength small compared to the scale of the temperature (or sound speed) profile, and approximate or numerical inversion of the Hankel transformed solution. The solution displays the characteristics found in experimental data but extensive comparison between the models and experimental data has not been carried out.

A virtual observatory for photoionized nebulae: the Mexican Million Models database (3MdB).

NASA Astrophysics Data System (ADS)

Morisset, C.; Delgado-Inglada, G.; Flores-Fajardo, N.

2015-04-01

Photoionization models obtained with numerical codes are widely used to study the physics of the interstellar medium (planetary nebulae, HII regions, etc). Grids of models are performed to understand the effects of the different parameters used to describe the regions on the observables (mainly emission line intensities). Most of the time, only a small part of the computed results of such grids are published, and they are sometimes hard to obtain in a user-friendly format. We present here the Mexican Million Models dataBase (3MdB), an effort to resolve both of these issues in the form of a database of photoionization models, easily accessible through the MySQL protocol, and containing a lot of useful outputs from the models, such as the intensities of 178 emission lines, the ionic fractions of all the ions, etc. Some examples of the use of the 3MdB are also presented.

Turbidity Currents With Equilibrium Basal Driving Layers: A Mechanism for Long Runout

NASA Astrophysics Data System (ADS)

Luchi, R.; Balachandar, S.; Seminara, G.; Parker, G.

2018-02-01

Turbidity currents run out over 100 km in lakes and reservoirs, and over 1,000 km in the ocean. They do so without dissipating themselves via excess entrainment of ambient water. Existing layer-averaged formulations cannot capture this. We use a numerical model to describe the temporal evolution of a turbidity current toward steady state under condition of zero net sediment flux at the bed. The flow self-partitions itself into two layers. The lower "driving layer" approaches an invariant flow thickness, velocity profile, and suspended sediment concentration profile that sequesters nearly all of the suspended sediment. This layer can continue indefinitely at steady state over a constant bed slope. The upper "driven layer" contains a small fraction of the suspended sediment. The devolution of the flow into these two layers likely allows the driving layer to run out long distances.

First principles determination of dislocation properties.

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

Hamilton, John C.

2003-12-01

This report details the work accomplished on first principles determination of dislocation properties. It contains an introduction and three chapters detailing three major accomplishments. First, we have used first principle calculations to determine the shear strength of an aluminum twin boundary. We find it to be remarkably small ({approx}17 mJ/m{sup 2}). This unexpected result is explained and will likely pertain for many other grain boundaries. Second, we have proven that the conventional explanation for finite grain boundary facets is wrong for a particular aluminum grain boundary. Instead of finite facets being stabilized by grain boundary stress, we find them tomore » originate from kinetic effects. Finally we report on a new application of the Frenkel-Kontorova model to understand reconstructions of (100) type surfaces. In addition to the commonly accepted formation of rectangular dislocation arrays, we find numerous other possible solutions to the model including hexagonal reconstructions and a clock-rotated structure.« less

On the synchrotron radiation reaction in external magnetic field

NASA Astrophysics Data System (ADS)

Tursunov, Arman; Kološ, Martin

2017-12-01

We study the dynamics of point electric charges undergoing radiation reaction force due to synchrotron radiation in the presence of external uniform magnetic field. The radiation reaction force cannot be neglected in many physical situations and its presence modifies the equations of motion significantly. The exact form of the equation of motion known as the Lorentz-Dirac equation contains higher order Schott term which leads to the appearance of the runaway solutions. We demonstrate effective computational ways to avoid such unphysical solutions and perform numerical integration of the dynamical equations. We show that in the ultrarelativistic case the Schott term is small and does not have considerable effect to the trajectory of a particle. We compare results with the covariant Landau-Lifshitz equation which is the first iteration of the Lorentz-Dirac equation. Even though the Landau-Lifshitz equation is thought to be approximative solution, we show that in realistic scenarios both approaches lead to identical results.

Bloch surface waves confined in one dimension with a single polymeric nanofibre

PubMed Central

Wang, Ruxue; Xia, Hongyan; Zhang, Douguo; Chen, Junxue; Zhu, Liangfu; Wang, Yong; Yang, Erchan; Zang, Tianyang; Wen, Xiaolei; Zou, Gang; Wang, Pei; Ming, Hai; Badugu, Ramachandram; Lakowicz, Joseph R.

2017-01-01

Polymeric fibres with small radii (such as ≤125 nm) are delicate to handle and should be laid down on a solid substrate to obtain practical devices. However, placing these nanofibres on commonly used glass substrates prevents them from guiding light. In this study, we numerically and experimentally demonstrate that when the nanofibre is placed on a suitable dielectric multilayer, it supports a guided mode, a Bloch surface wave (BSW) confined in one dimension. The physical origin of this new mode is discussed in comparison with the typical two-dimensional BSW mode. Polymeric nanofibres are easily fabricated to contain fluorophores, which make the dielectric nanofibre and multilayer configuration suitable for developing a large range of new nanometric scale devices, such as processor–memory interconnections, devices with sensitivity to target analytes, incident polarization and multi-colour BSW modes. PMID:28155871

LSSA large area silicon sheet task continuous Czochralski process development

NASA Technical Reports Server (NTRS)

Rea, S. N.

1978-01-01

A Czochralski crystal growing furnace was converted to a continuous growth facility by installation of a premelter to provide molten silicon flow into the primary crucible. The basic furnace is operational and several trial crystals were grown in the batch mode. Numerous premelter configurations were tested both in laboratory-scale equipment as well as in the actual furnace. The best arrangement tested to date is a vertical, cylindrical graphite heater containing small fused silicon test tube liner in which the incoming silicon is melted and flows into the primary crucible. Economic modeling of the continuous Czochralski process indicates that for 10 cm diameter crystal, 100 kg furnace runs of four or five crystals each are near-optimal. Costs tend to asymptote at the 100 kg level so little additional cost improvement occurs at larger runs. For these conditions, crystal cost in equivalent wafer area of around $20/sq m exclusive of polysilicon and slicing was obtained.

First results from the THOR experiment imaging thunderstorm activity from the ISS.

NASA Astrophysics Data System (ADS)

Chanrion, Olivier; Neubert, Torsten; Mogensen, Andreas; Yair, Yoav; Stendel, Martin; Larsen, Niels

2016-04-01

Video imaging from the THOR experiment conducted on International Space Station by the Danish astronaut Andreas Mogensen has been analyzed. The observations we report in this paper were taken with a color camera from the vantage point of the Cupola, tracking thunderstorm activity over the Bay of Bengal. Among many lightning, the observations contain a sprite, a blue jet and numerous small blue discharge regions at the top of a tall cumulonimbus cloud. The latter are interpreted as electric discharges between layers at the uppermost layers of the cloud and to the screening layer formed at the very edge between the cloud and the surrounding atmosphere. The observations are the first of their kind and give new insights into the charge structure at the top of clouds in the tropical tropopause regions, a region that is difficult to observe and to access.

Acoustic propagation in a thermally stratified atmosphere

NASA Technical Reports Server (NTRS)

Vanmoorhem, W. K.

1987-01-01

Acoustic propagation in an atmosphere with a specific form of temperature profile has been investigated by analytical means. The temperature profile used is representative of an actual atmospheric profile and contains three free parameters. Both lapse and inversion cases have been considered. Although ray solution have been considered the primary emphasis has been on solutions of the acoustic wave equation with point force where the sound speed varies with height above the ground corresponding to the assumed temperature profile. The method used to obtain the solution of the wave equation is based on Hankel transformation of the wave equation, approximate solution of the transformed equation for wavelength small compared to the scale of the temperature (or sound speed) profile, and approximate or numerical inversion of the Hankel transformed solution. The solution displays the characteristics found in experimental data but extensive comparison between the models and experimental data has not been carried out.

STARSYS: A view after WARC-92

NASA Astrophysics Data System (ADS)

Kaveeshwar, Ashok; Rodriguez, Raul

1993-01-01

The STARSYS system is aimed at providing low cost global positioning and messaging by satellite. STARSYS is a data only system using very brief message transmission times. Code Division Multiple Access (CDMA) is used for frequency sharing; it enables transmitted data to be coded for unique user identification and also to employ Doppler and radio ranging to determine the geographical location of a transmitting terminal. The STARSYS system is composed of the field receiver/transmitter, the Low Earth Orbit (LEO) satellite constellation and the ground station elements. Each message transmission is able to contain up to thirty two digital characters. Market applications are numerous: theft control, vehicle and logistic tracking and messaging, personal communications, utility and environmental data acquisition and transfer. Co-primary frequency allocation at WARC-92 accelerated interest for potential customers and investors, although the amount of frequency allocation (less than 1 GHz) is small.

Pulmonary microvascular cytology can detect tumor cells of intravascular lymphoma.

PubMed

Ishiguro, Takashi; Takayanagi, Noboru; Yanagisawa, Tsutomu; Kagiyama, Naho; Saito, Hiroo; Sugita, Yutaka; Kojima, Masaru

2009-01-01

A 68-year-old man was admitted to our hospital for indistinct consciousness, progressive dyspnea, night sweats and fever of 2 weeks duration. Hypoxemia, thrombocytopenia, and elevated serum lactate dehydrogenase were found. Computed tomography was negative except for a small bilateral pleural effusion. Chest perfusion scintigraphy showed inhomogeneous perfusion thought unlikely to be pulmonary artery thromboembolism. Intravascular large B-cell lymphoma was suspected, and a pulmonary microvascular cytology specimen was obtained that contained numerous large lymphoma cells. Because the patient's condition was rapidly deteriorating, we started chemotherapy on the basis of the pulmonary microvascular cytology findings, and he improved. Later, atypical lymphocytes similar to those in the pulmonary microvascular cytology specimen were found in a bone marrow specimen. He was diagnosed as having diffuse large B-cell lymphoma. Because lymphoma cells were found in the pulmonary microvasculature, intravascular lymphoma was also diagnosed. Pulmonary microvascular cytology was helpful to detect lymphoma cells in the pulmonary microvasculature.

A simple dynamic subgrid-scale model for LES of particle-laden turbulence

NASA Astrophysics Data System (ADS)

Park, George Ilhwan; Bassenne, Maxime; Urzay, Javier; Moin, Parviz

2017-04-01

In this study, a dynamic model for large-eddy simulations is proposed in order to describe the motion of small inertial particles in turbulent flows. The model is simple, involves no significant computational overhead, contains no adjustable parameters, and is flexible enough to be deployed in any type of flow solvers and grids, including unstructured setups. The approach is based on the use of elliptic differential filters to model the subgrid-scale velocity. The only model parameter, which is related to the nominal filter width, is determined dynamically by imposing consistency constraints on the estimated subgrid energetics. The performance of the model is tested in large-eddy simulations of homogeneous-isotropic turbulence laden with particles, where improved agreement with direct numerical simulation results is observed in the dispersed-phase statistics, including particle acceleration, local carrier-phase velocity, and preferential-concentration metrics.

An investigation of chaotic Kolmogorov flows

NASA Technical Reports Server (NTRS)

Platt, N.; Sirovich, L.; Fitzmaurice, N.

1990-01-01

A two dimensional flow governed by the incompressible Navier-Stokes equations with a steady spatially periodic forcing (known as the Kolmogorov flow) is numerically simulated. The behavior of the flow and its transition states as the Reynolds number (Re) varies is investigated in detail, as well as a number of the flow features. A sequence of bifurcations is shown to take place in the flow as Re varied. Two main regimes of the flow were observed: small and large scale structure regimes corresponding to different ranges of Re. Each of the regimes includes a number of quasiperiodic, chaotic, and relaminarization windows. In addition, each range contains a chaotic window with non-ergodic chaotic attractors. Spatially disordered, but temporally steady states were discovered in large scale structure regime. Features of the diverse cases are displayed in terms of the temporal power spectrum, Poincare sections and, where possible, Lyapunov exponents and Kaplan-Yorke dimension.

Multiple-length-scale deformation analysis in a thermoplastic polyurethane

PubMed Central

Sui, Tan; Baimpas, Nikolaos; Dolbnya, Igor P.; Prisacariu, Cristina; Korsunsky, Alexander M.

2015-01-01

Thermoplastic polyurethane elastomers enjoy an exceptionally wide range of applications due to their remarkable versatility. These block co-polymers are used here as an example of a structurally inhomogeneous composite containing nano-scale gradients, whose internal strain differs depending on the length scale of consideration. Here we present a combined experimental and modelling approach to the hierarchical characterization of block co-polymer deformation. Synchrotron-based small- and wide-angle X-ray scattering and radiography are used for strain evaluation across the scales. Transmission electron microscopy image-based finite element modelling and fast Fourier transform analysis are used to develop a multi-phase numerical model that achieves agreement with the combined experimental data using a minimal number of adjustable structural parameters. The results highlight the importance of fuzzy interfaces, that is, regions of nanometre-scale structure and property gradients, in determining the mechanical properties of hierarchical composites across the scales. PMID:25758945

Unsteady aerodynamic analyses for turbomachinery aeroelastic predictions

NASA Technical Reports Server (NTRS)

Verdon, Joseph M.; Barnett, M.; Ayer, T. C.

1994-01-01

Applications for unsteady aerodynamics analysis in this report are: (1) aeroelastic: blade flutter and forced vibration; (2) aeroacoustic: noise generation; (3) vibration and noise control; and (4) effects of unsteadiness on performance. This requires that the numerical simulations and analytical modeling be accurate and efficient and contain realistic operating conditions and arbitrary modes of unsteady excitation. The assumptions of this application contend that: (1) turbulence and transition can be modeled with the Reynolds averaged and using Navier-Stokes equations; (2) 'attached' flow with high Reynolds number will require thin-layer Navier-Stokes equations, or inviscid/viscid interaction analyses; (3) small-amplitude unsteady excitations will need nonlinear steady and linearized unsteady analyses; and (4) Re to infinity will concern inviscid flow. Several computer programs (LINFLO, CLT, UNSVIS, AND SFLOW-IVI) are utilized for these analyses. Results and computerized grid examples are shown. This report was given during NASA LeRC Workshop on Forced Response in Turbomachinery in August of 1993.

Boundary-layer receptivity due to a wall suction and control of Tollmien-Schlichting waves

NASA Technical Reports Server (NTRS)

Bodonyi, R. J.; Duck, P. W.

1992-01-01

A numerical study of the generation of Tollmien-Schlichting (T-S) waves due to the interaction between a small free-stream disturbance and a small localized suction slot on an otherwise flat surface was carried out using finite difference methods. The nonlinear steady flow is of the viscous-inviscid interactive type while the unsteady disturbed flow is assumed to be governed by the Navier-Stokes equations linearized about this flow. Numerical solutions illustrate the growth or decay of T-S waves generated by the interaction between the free-stream disturbance and the suction slot, depending on the value of the scaled Strouhal number. An important result of this receptivity problem is the numerical determination of the amplitude of the T-S waves and the demonstration of the possible active control of the growth of T-S waves.

Boundary-layer receptivity due to a wall suction and control of Tollmien-Schlichting waves

NASA Technical Reports Server (NTRS)

Bodonyi, R. J.; Duck, P. W.

1990-01-01

A numerical study of the generation of Tollmien-Schlichting (T-S) waves due to the interaction between a small free-stream disturbance and a small localized suction slot on an otherwise flat surface was carried out using finite difference methods. The nonlinear steady flow is of the viscous-inviscid interactive type while the unsteady disturbed flow is assumed to be governed by the Navier-Stokes equations linearized about this flow. Numerical solutions illustrate the growth or decay of T-S waves generated by the interaction between the free-stream disturbance and the suction slot, depending on the value of the scaled Strouhal number. An important result of this receptivity problem is the numerical determination of the amplitude of the T-S waves and the demonstration of the possible active control of the growth of T-S waves.

On the buckling of elastic rings by external confinement.

PubMed

Hazel, Andrew L; Mullin, Tom

2017-05-13

We report the results of an experimental and numerical investigation into the buckling of thin elastic rings confined within containers of circular or regular polygonal cross section. The rings float on the surface of water held in the container and controlled removal of the fluid increases the confinement of the ring. The increased compressive forces can cause the ring to buckle into a variety of shapes. For the circular container, finite perturbations are required to induce buckling, whereas in polygonal containers the buckling occurs through a linear instability that is closely related to the canonical Euler column buckling. A model based on Kirchhoff-Love beam theory is developed and solved numerically, showing good agreement with the experiments and revealing that in polygons increasing the number of sides means that buckling occurs at reduced levels of confinement.This article is part of the themed issue 'Patterning through instabilities in complex media: theory and applications.' © 2017 The Author(s).

On the buckling of elastic rings by external confinement

PubMed Central

Hazel, Andrew L.

2017-01-01

We report the results of an experimental and numerical investigation into the buckling of thin elastic rings confined within containers of circular or regular polygonal cross section. The rings float on the surface of water held in the container and controlled removal of the fluid increases the confinement of the ring. The increased compressive forces can cause the ring to buckle into a variety of shapes. For the circular container, finite perturbations are required to induce buckling, whereas in polygonal containers the buckling occurs through a linear instability that is closely related to the canonical Euler column buckling. A model based on Kirchhoff–Love beam theory is developed and solved numerically, showing good agreement with the experiments and revealing that in polygons increasing the number of sides means that buckling occurs at reduced levels of confinement. This article is part of the themed issue ‘Patterning through instabilities in complex media: theory and applications.’ PMID:28373386

Number versus Extent in Newborns' Spontaneous Preference for Collections of Dots

ERIC Educational Resources Information Center

Turati, Chiara; Gava, Lucia; Valenza, Eloisa; Ghirardi, Valentina

2013-01-01

This study investigated processing of number and extent in newborns. Using visual preference, we showed that newborns discriminated between small sets of dot collections relying solely on implicit numerical information when non-numerical continuous variables were strictly controlled (Experiment 1), and solely on continuous information when…

Numerical solution for the velocity-derivative skewness of a low-Reynolds-number decaying Navier-Stokes flow

NASA Technical Reports Server (NTRS)

Deissler, Robert G.

1990-01-01

The variation of the velocity-derivative skewness of a Navier-Stokes flow as the Reynolds number goes toward zero is calculated numerically. The value of the skewness, which has been somewhat controversial, is shown to become small at low Reynolds numbers.

Gaseous composition measured by a chemical ionization mass spectrometer in fresh and aged ship plumes

NASA Astrophysics Data System (ADS)

Faxon, Cameron; Psichoudaki, Magda; Kuuluvainen, Heino; Hallquist, Åsa; Thomson, Erik; Pettersson, Jan; Hallquist, Mattias

2015-04-01

The port of Gothenburg is the largest port of the Nordic countries with numerous ships calling the port daily. The ship exhausts contain numerous pollutants including gases such as SO2 and NOx as well as particulate matter and soot. The exhaust also contains numerous organic compounds, a large fraction of which are unidentified. These organics are oxidized in the atmosphere producing more oxygenated and potentially less volatile compounds that may contribute to the secondary organic aerosol (SOA). This work focuses on the characterization of fresh gaseous species present in the exhaust plumes of the passing ships and also on their photochemical aging. Between 26 September and 12 November 2014 measurements were conducted at a sampling site located on a small peninsula at the entrance of Gothenburg's port. The campaign was divided in two periods. During the first period, the fresh plumes of the passing ships were measured through a main inlet. During the second period, the sample passed through the same inlet and was then introduced into a Potential Aerosol Mass (PAM) reactor. The PAM reactor uses UV lamps and high concentrations of oxidants (OH radicals and O3) to oxidize the organic species present in the plumes. The oxidation that takes place within the reactor can be equivalent to up to one week of atmospheric oxidation. Preliminary tests showed that the oxidation employed in the current camping corresponded to 3.4 days in the atmosphere. A Time-of-Flight Chemical Ionization Mass Spectrometer (ToF-CIMS) was employed to monitor the concentration of different organic species present in the fresh and aged plumes. Water (positive) and iodide (negative) ionization methods were employed were water was primarily used for fresh plumes (large fraction of non-polar compounds) while iodide was used for the aged plumes (primarily oxidised products). The H2O, O3 and SO2 concentrations inside the PAM chamber were monitored, and an organic tracer for OH exposure determination was also continuously measured. The dominant species concentrations of both fresh and aged ship plumes are presented and their emission factors are estimated from concurrent CO2 measurements.

ZERODUR 4-m blank surviving up to 20 g acceleration

NASA Astrophysics Data System (ADS)

Westerhoff, Thomas; Werner, Thomas; Gehindy, Thorsten

2017-09-01

The glass ceramic ZERODUR developed as astronomical telescope mirror substrate material has been widely used in many telescopes due to its excellent small coefficient of thermal expansion. Many large and medium sized mirror substrate blanks have been delivered in the almost 50 years of ZERODUR business so far. Packaging and transportation of mirror substrates of 4 to 8 m in diameter with a weight between 3 and 20 tons requires special attention and sophisticated skills to successful deliver the blanks to their destination at polishing shops all over the world. Typically, a combination of road and sea transport needs to be organized. The requirements on the transport container are depending on the transport route and may vary from destination to destination. In any case the container needs to be able to sufficiently support the multi ton ZERODUR blank to avoid breaking under gravity. Additionally, the configuration needs to be able to absorb shocks happening during transport and loading between truck trailer and ship. For insurance reasons the transport container is always equipped with a GPS trackable shock recorder allowing to download the recorded accelerations on the container and the blank throughout the entire journey. This paper reports on the event of a 4 m class ZERODUR blank exposed to shocks up to 20 g during transport. The event will be discussed in detail together with lessons learned to avoid such events for future transports. Additionally, the 20 g acceleration will be discussed in respect to the data on bending strength for ZERODUR ground surfaces reported in numerous papers by Peter Hartmann et.al. in the last couple of years.

Application of a quick-freezing and deep-etching method to pathological diagnosis: a case of elastofibroma.

PubMed

Hemmi, Akihiro; Tabata, Masahiko; Homma, Taku; Ohno, Nobuhiko; Terada, Nobuo; Fujii, Yasuhisa; Ohno, Shinichi; Nemoto, Norimichi

2006-04-01

A case of elastofibroma in a middle-aged Japanese woman was examined by the quick-freezing and deep-etching (QF-DE) method, as well as by immunohistochemistry and conventional electron microscopy. The slowly growing tumor developed at the right scapular region and was composed of fibrous connective tissue with unique elastic materials called elastofibroma fibers. A normal elastic fiber consists of a central core and peripheral zone, in which the latter has small aggregates of 10 nm microfibrils. By the QF-DE method, globular structures consisting of numerous fibrils (5-20 nm in width) were observed between the collagen bundles. We could confirm that they were microfibril-rich peripheral zones of elastofibroma fibers by comparing the replica membrane and conventional electron microscopy. One of the characteristics of elastofibroma fibers is that they are assumed to contain numerous microfibrils. Immunohistochemically, spindle tumor cells showed positive immunoreaction for vimentin, whereas alpha-smooth muscle actin, desmin, S-100 protein and CD34 showed negative immunoreaction. By conventional electron microscopy, the tumor cell had thin cytoplasmic processes, pinocytotic vesicles and prominent rough endoplasmic reticulum. Abundant intracytoplasmic filaments were observed in some tumor cells. Thick lamina-like structures along with their inner nuclear membrane were often observed in the tumor cell nuclei. The whole image of the tumor cell was considered to be a periosteal-derived cell, which would produce numerous microfibrils in the peripheral zone of elastofibroma fibers. This study indicated that the QF-DE method could be applied to the pathological diagnosis and analysis of pathomechanism, even for surgical specimens obtained from a patient.

An Experimental and Numerical Study on Cracking Behavior of Brittle Sandstone Containing Two Non-coplanar Fissures Under Uniaxial Compression

NASA Astrophysics Data System (ADS)

Yang, Sheng-Qi; Tian, Wen-Ling; Huang, Yan-Hua; Ranjith, P. G.; Ju, Yang

2016-04-01

To understand the fracture mechanism in all kinds of rock engineering, it is important to investigate the fracture evolution behavior of pre-fissured rock. In this research, we conducted uniaxial compression experiments to evaluate the influence of ligament angle on the strength, deformability, and fracture coalescence behavior of rectangular prismatic specimens (80 × 160 × 30 mm) of brittle sandstone containing two non-coplanar fissures. The experimental results show that the peak strength of sandstone containing two non-coplanar fissures depends on the ligament angle, but the elastic modulus is not closely related to the ligament angle. With the increase of ligament angle, the peak strength decreased at a ligament angle of 60°, before increasing up to our maximum ligament angle of 120°. Crack initiation, propagation, and coalescence were all observed and characterized from the inner and outer tips of pre-existing non-coplanar fissures using photographic monitoring. Based on the results, the sequence of crack evolution in sandstone containing two non-coplanar fissures was analyzed in detail. In order to fully understand the crack evolution mechanism of brittle sandstone, numerical simulations using PFC2D were performed for specimens containing two non-coplanar fissures under uniaxial compression. The results are in good agreement with the experimental results. By analyzing the stress field, the crack evolution mechanism in brittle sandstone containing two non-coplanar fissures under uniaxial compression is revealed. These experimental and numerical results are expected to improve the understanding of the unstable fracture mechanism of fissured rock engineering structures.

Exploring Managerial Commitment towards SPI in Small and Very Small Enterprises

NASA Astrophysics Data System (ADS)

O'Connor, Rory V.; Basri, Shuib; Coleman, Gerry

This paper compares and contrasts the results of two similar studies into the software process practices in Irish Small and Very Small Enterprises. The first study contains rich findings in relation to the role and influence of managerial experience and style, with particular respect to the company founder and software development managers in small to medium seized enterprises (SMEs), whilst the second study contains extensive findings in relation to people and management involvement / commitment and SPI goal planning in very small enterprises (VSEs). By combining these results of these two studies of Irish SMEs/VSEs we can develop a rich picture of managerial commitment towards SPI and in particular explore the similarities between Small and Very Small Enterprises.

Children with mathematical learning disability fail in recruiting verbal and numerical brain regions when solving simple multiplication problems.

PubMed

Berteletti, Ilaria; Prado, Jérôme; Booth, James R

2014-08-01

Greater skill in solving single-digit multiplication problems requires a progressive shift from a reliance on numerical to verbal mechanisms over development. Children with mathematical learning disability (MD), however, are thought to suffer from a specific impairment in numerical mechanisms. Here we tested the hypothesis that this impairment might prevent MD children from transitioning toward verbal mechanisms when solving single-digit multiplication problems. Brain activations during multiplication problems were compared in MD and typically developing (TD) children (3rd to 7th graders) in numerical and verbal regions which were individuated by independent localizer tasks. We used small (e.g., 2 × 3) and large (e.g., 7 × 9) problems as these problems likely differ in their reliance on verbal versus numerical mechanisms. Results indicate that MD children have reduced activations in both the verbal (i.e., left inferior frontal gyrus and left middle temporal to superior temporal gyri) and the numerical (i.e., right superior parietal lobule including intra-parietal sulcus) regions suggesting that both mechanisms are impaired. Moreover, the only reliable activation observed for MD children was in the numerical region when solving small problems. This suggests that MD children could effectively engage numerical mechanisms only for the easier problems. Conversely, TD children showed a modulation of activation with problem size in the verbal regions. This suggests that TD children were effectively engaging verbal mechanisms for the easier problems. Moreover, TD children with better language skills were more effective at engaging verbal mechanisms. In conclusion, results suggest that the numerical- and language-related processes involved in solving multiplication problems are impaired in MD children. Published by Elsevier Ltd.

Experience of the Small Grower

Treesearch

Emmett Jordon

2002-01-01

The small grower cannot afford costly facilities, equipment, or containers. The grower usually does about everything by hand and gets help from family members and friends to get started. I describe the approach I use to produce longleaf pine container stock.

Commercial Aviation : issues regarding federal assistance for enhancing air service to small communities

DOT National Transportation Integrated Search

2003-03-01

Small communities have long faced challenges in obtaining or retaining the commercial air service they desire. These challenges are increasing as many U.S. airlines try to stem unprecedented financial losses through numerous cost-cutting measures, in...

Arkansas' Curriculum Guide. Competency Based Typewriting.

ERIC Educational Resources Information Center

Arkansas State Dept. of Education, Little Rock. Div. of Vocational, Technical and Adult Education.

This guide contains the essential parts of a total curriculum for a one-year typewriting course at the secondary school level. Addressed in the individual units of the guide are the following topics: alphabetic keyboarding, numeric keyboarding, basic symbol keyboarding, skill development, problem typewriting, ten-key numeric pads, production…

36 CFR 216.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 36 Parks, Forests, and Public Property 2 2014-07-01 2014-07-01 false Definitions. 216.2 Section... PUBLIC IN THE FORMULATION OF FOREST SERVICE DIRECTIVES § 216.2 Definitions. (a) The Forest Service Manual consists of numerous volumes organized by numerically coded subject matter. The volumes contain legal...

Creating Poetry.

ERIC Educational Resources Information Center

Drury, John

Encouraging exploration and practice, this book offers hundreds of exercises and numerous tips covering every step involved in creating poetry. Each chapter is a self-contained unit offering an overview of material in the chapter, a definition of terms, and poetry examples from well-known authors designed to supplement the numerous exercises.…

Act on Numbers: Numerical Magnitude Influences Selection and Kinematics of Finger Movement

PubMed Central

Rugani, Rosa; Betti, Sonia; Ceccarini, Francesco; Sartori, Luisa

2017-01-01

In the past decade hand kinematics has been reliably adopted for investigating cognitive processes and disentangling debated topics. One of the most controversial issues in numerical cognition literature regards the origin – cultural vs. genetically driven – of the mental number line (MNL), oriented from left (small numbers) to right (large numbers). To date, the majority of studies have investigated this effect by means of response times, whereas studies considering more culturally unbiased measures such as kinematic parameters are rare. Here, we present a new paradigm that combines a “free response” task with the kinematic analysis of movement. Participants were seated in front of two little soccer goals placed on a table, one on the left and one on the right side. They were presented with left- or right-directed arrows and they were instructed to kick a small ball with their right index toward the goal indicated by the arrow. In a few test trials participants were presented also with a small (2) or a large (8) number, and they were allowed to choose the kicking direction. Participants performed more left responses with the small number and more right responses with the large number. The whole kicking movement was segmented in two temporal phases in order to make a hand kinematics’ fine-grained analysis. The Kick Preparation and Kick Finalization phases were selected on the basis of peak trajectory deviation from the virtual midline between the two goals. Results show an effect of both small and large numbers on action execution timing. Participants were faster to finalize the action when responding to small numbers toward the left and to large number toward the right. Here, we provide the first experimental demonstration which highlights how numerical processing affects action execution in a new and not-overlearned context. The employment of this innovative and unbiased paradigm will permit to disentangle the role of nature and culture in shaping the direction of MNL and the role of finger in the acquisition of numerical skills. Last but not least, similar paradigms will allow to determine how cognition can influence action execution. PMID:28912743

Hardware-Independent Proofs of Numerical Programs

NASA Technical Reports Server (NTRS)

Boldo, Sylvie; Nguyen, Thi Minh Tuyen

2010-01-01

On recent architectures, a numerical program may give different answers depending on the execution hardware and the compilation. Our goal is to formally prove properties about numerical programs that are true for multiple architectures and compilers. We propose an approach that states the rounding error of each floating-point computation whatever the environment. This approach is implemented in the Frama-C platform for static analysis of C code. Small case studies using this approach are entirely and automatically proved

Numerical Study of a Convective Turbulence Encounter

NASA Technical Reports Server (NTRS)

Proctor, Fred H.; Hamilton, David W.; Bowles, Roland L.

2002-01-01

A numerical simulation of a convective turbulence event is investigated and compared with observational data. The specific case was encountered during one of NASA's flight tests and was characterized by severe turbulence. The event was associated with overshooting convective turrets that contained low to moderate radar reflectivity. Model comparisons with observations are quite favorable. Turbulence hazard metrics are proposed and applied to the numerical data set. Issues such as adequate grid size are examined.

Numerical analysis of fluid flow and heat transfer during melting inside a cylindrical container for thermal energy storage system

NASA Astrophysics Data System (ADS)

Bellan, Selvan; Cheok, Cho Hyun; Gokon, Nobuyuki; Matsubara, Koji; Kodama, Tatsuya

2017-06-01

This paper presents a numerical analysis of unconstrained melting of high temperature(>1000K) phase change material (PCM) inside a cylindrical container. Sodium chloride and Silicon carbide have been used as phase change material and shell of the capsule respectively. The control volume discretization approach has been used to solve the conservation equations of mass, momentum and energy. The enthalpy-porosity method has been used to track the solid-liquid interface of the PCM during melting process. Transient numerical simulations have been performed in order to study the influence of radius of the capsule and the Stefan number on the heat transfer rate. The simulation results show that the counter-clockwise Buoyancy driven convection over the top part of the solid PCM enhances the melting rate quite faster than the bottom part.

Calibration and validation of a small-scale urban surface water flood event using crowdsourced images

NASA Astrophysics Data System (ADS)

Green, Daniel; Yu, Dapeng; Pattison, Ian

2017-04-01

Surface water flooding occurs when intense precipitation events overwhelm the drainage capacity of an area and excess overland flow is unable to infiltrate into the ground or drain via natural or artificial drainage channels, such as river channels, manholes or SuDS. In the UK, over 3 million properties are at risk from surface water flooding alone, accounting for approximately one third of the UK's flood risk. The risk of surface water flooding is projected to increase due to several factors, including population increases, land-use alterations and future climatic changes in precipitation resulting in an increased magnitude and frequency of intense precipitation events. Numerical inundation modelling is a well-established method of investigating surface water flood risk, allowing the researcher to gain a detailed understanding of the depth, velocity, discharge and extent of actual or hypothetical flood scenarios over a wide range of spatial scales. However, numerical models require calibration of key hydrological and hydraulic parameters (e.g. infiltration, evapotranspiration, drainage rate, roughness) to ensure model outputs adequately represent the flood event being studied. Furthermore, validation data such as crowdsourced images or spatially-referenced flood depth collected during a flood event may provide a useful validation of inundation depth and extent for actual flood events. In this study, a simplified two-dimensional inertial based flood inundation model requiring minimal pre-processing of data (FloodMap-HydroInundation) was used to model a short-duration, intense rainfall event (27.8 mm in 15 minutes) that occurred over the Loughborough University campus on the 28th June 2012. High resolution (1m horizontal, +/- 15cm vertical) DEM data, rasterised Ordnance Survey topographic structures data and precipitation data recorded at the University weather station were used to conduct numerical modelling over the small (< 2km2), contained urban catchment. To validate model outputs and allow a reconstruction of spatially referenced flood depth and extent during the flood event, crowdsourced images were obtained from social media (Twitter) and from individuals present during the flood event via the University noticeboards, as well as using dGPS flood depth data collected at one of the worst affected areas. An investigation into the sensitivity of key model parameters suggests that the numerical model code is highly sensitivity to changes within the recommended range of roughness and infiltration values, as well as changes in DEM and building mesh resolutions, but less sensitive to changes in evapotranspiration and drainage capacity parameters. The study also demonstrates the potential of using crowdsourced images to validate urban surface water flood models and inform parameterisation when calibrating numerical inundation models.

Community Air Sensor Network (CAIRSENSE) Project: Lower Cost, Continuous Ambient Monitoring Methods

EPA Science Inventory

Advances in air pollution sensor technology have enabled the development of small and low cost systems to measure outdoor air pollution. The deployment of numerous sensors across a small geographic area would have potential benefits to supplement existing monitoring networks and ...

Computerized Numerical Control Test Item Bank.

ERIC Educational Resources Information Center

Reneau, Fred; And Others

This guide contains 285 test items for use in teaching a course in computerized numerical control. All test items were reviewed, revised, and validated by incumbent workers and subject matter instructors. Items are provided for assessing student achievement in such aspects of programming and planning, setting up, and operating machines with…

System Simulation by Recursive Feedback: Coupling A Set of Stand-Alone Subsystem Simulations

NASA Technical Reports Server (NTRS)

Nixon, Douglas D.; Hanson, John M. (Technical Monitor)

2002-01-01

Recursive feedback is defined and discussed as a framework for development of specific algorithms and procedures that propagate the time-domain solution for a dynamical system simulation consisting of multiple numerically coupled self-contained stand-alone subsystem simulations. A satellite motion example containing three subsystems (other dynamics, attitude dynamics, and aerodynamics) has been defined and constructed using this approach. Conventional solution methods are used in the subsystem simulations. Centralized and distributed versions of coupling structure have been addressed. Numerical results are evaluated by direct comparison with a standard total-system simultaneous-solution approach.

Evaluation of a Numeracy Intervention Program Focusing on Basic Numerical Knowledge and Conceptual Knowledge: A Pilot Study.

ERIC Educational Resources Information Center

Kaufmann, Liane; Handl, Pia; Thony, Brigitte

2003-01-01

In this study, six elementary grade children with developmental dyscalculia were trained individually and in small group settings with a one-semester program stressing basic numerical knowledge and conceptual knowledge. All the children showed considerable and partly significant performance increases on all calculation components. Results suggest…

Crossing the Communication Barrier: Facilitating Communication in Mixed Groups of Deaf and Hearing Students

ERIC Educational Resources Information Center

Marchetti, Carol; Foster, Susan; Long, Gary; Stinson, Michael

2012-01-01

Teachers of introductory technical courses such as statistics face numerous challenges in the classroom, including student motivation and mathematical background, and difficulties in interpreting numerical results in context. Cooperative learning through small groups addresses many such challenges, but students for whom spoken English is not their…

Optimization of rheological properties of self-consolidating concrete by means of numerical simulations, to avoid formwork filling problems in presence of reinforcement bars.

DOT National Transportation Integrated Search

2012-02-01

The influence of the rebar configuration on the occurrence of dead zones (= zero velocity) during flow of Self-Consolidating Concrete : in formworks has been investigated by single fluid numerical simulations. The main findings showed that for small ...

The Impact of Verbal Working Memory on Number-Space Associations

ERIC Educational Resources Information Center

Ginsburg, Véronique; van Dijck, Jean-Philippe; Previtali, Paola; Fias, Wim; Gevers, Wim

2014-01-01

Spatial-numerical associations are observed when participants perform number categorization tasks. One such observation is the spatial numerical associations of response codes (SNARC) effect, showing an association between small numbers and the left-hand side and between large numbers and the right-hand side. It has long been argued that this…

Next-to-leading order Balitsky-Kovchegov equation with resummation

DOE PAGES

Lappi, T.; Mantysaari, H.

2016-05-03

Here, we solve the Balitsky-Kovchegov evolution equation at next-to-leading order accuracy including a resummation of large single and double transverse momentum logarithms to all orders. We numerically determine an optimal value for the constant under the large transverse momentum logarithm that enables including a maximal amount of the full NLO result in the resummation. When this value is used, the contribution from the α 2 s terms without large logarithms is found to be small at large saturation scales and at small dipoles. Close to initial conditions relevant for phenomenological applications, these fixed-order corrections are shown to be numerically important.

Infrared thermography applied to the study of heated and solar pavement: from numerical modeling to small scale laboratory experiments

NASA Astrophysics Data System (ADS)

Le Touz, N.; Toullier, T.; Dumoulin, J.

2017-05-01

The present study addresses the thermal behaviour of a modified pavement structure to prevent icing at its surface in adverse winter time conditions or overheating in hot summer conditions. First a multi-physic model based on infinite elements method was built to predict the evolution of the surface temperature. In a second time, laboratory experiments on small specimen were carried out and the surface temperature was monitored by infrared thermography. Results obtained are analyzed and performances of the numerical model for real scale outdoor application are discussed. Finally conclusion and perspectives are proposed.

Short-time self-diffusion coefficient of a particle in a colloidal suspension bounded by a microchannel: Virial expansions and simulation

NASA Astrophysics Data System (ADS)

Kȩdzierski, Marcin; Wajnryb, Eligiusz

2011-10-01

Self-diffusion of colloidal particles confined to a cylindrical microchannel is considered theoretically and numerically. Virial expansion of the self-diffusion coefficient is performed. Two-body and three-body hydrodynamic interactions are evaluated with high precision using the multipole method. The multipole expansion algorithm is also used to perform numerical simulations of the self-diffusion coefficient, valid for all possible particle packing fractions. Comparison with earlier results shows that the widely used method of reflections is insufficient for calculations of hydrodynamic interactions even for small packing fractions and small particles radii, contrary to the prevalent opinion.

Kelvin-wave cascade in the vortex filament model

NASA Astrophysics Data System (ADS)

Baggaley, Andrew W.; Laurie, Jason

2014-01-01

The small-scale energy-transfer mechanism in zero-temperature superfluid turbulence of helium-4 is still a widely debated topic. Currently, the main hypothesis is that weakly nonlinear interacting Kelvin waves (KWs) transfer energy to sufficiently small scales such that energy is dissipated as heat via phonon excitations. Theoretically, there are at least two proposed theories for Kelvin-wave interactions. We perform the most comprehensive numerical simulation of weakly nonlinear interacting KWs to date and show, using a specially designed numerical algorithm incorporating the full Biot-Savart equation, that our results are consistent with the nonlocal six-wave KW interactions as proposed by L'vov and Nazarenko.

The unsteady laminar boundary layer on an axisymmetric body subject to small-amplitude fluctuations in the free-stream velocity

NASA Technical Reports Server (NTRS)

Duck, Peter W.

1991-01-01

The effect of small-amplitude, time-periodic, free-stream disturbances on an otherwise steady axisymmetric boundary layer on a circular cylinder is considered. Numerical solutions to the problem are presented, and an asymptotic solution to the flow, valid far downstream along the axis of the cylinder is detailed. Particular emphasis is placed on the unsteady eigensolutions that occur far downstream, which turn out to be very different from the analogous planar eigensolutions. These axisymmetric eigensolutions are computed numerically and also are described by asymptotic analyses valid for low and high frequencies of oscillation.

Prediction of matching condition for a microstrip subsystem using artificial neural network and adaptive neuro-fuzzy inference system

NASA Astrophysics Data System (ADS)

Salehi, Mohammad Reza; Noori, Leila; Abiri, Ebrahim

2016-11-01

In this paper, a subsystem consisting of a microstrip bandpass filter and a microstrip low noise amplifier (LNA) is designed for WLAN applications. The proposed filter has a small implementation area (49 mm2), small insertion loss (0.08 dB) and wide fractional bandwidth (FBW) (61%). To design the proposed LNA, the compact microstrip cells, an field effect transistor, and only a lumped capacitor are used. It has a low supply voltage and a low return loss (-40 dB) at the operation frequency. The matching condition of the proposed subsystem is predicted using subsystem analysis, artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS). To design the proposed filter, the transmission matrix of the proposed resonator is obtained and analysed. The performance of the proposed ANN and ANFIS models is tested using the numerical data by four performance measures, namely the correlation coefficient (CC), the mean absolute error (MAE), the average percentage error (APE) and the root mean square error (RMSE). The obtained results show that these models are in good agreement with the numerical data, and a small error between the predicted values and numerical solution is obtained.

Late steps of egg cell differentiation are accelerated by pollination in Zea mays L.

PubMed

Mól, R; Idzikowska, K; Dumas, C; Matthys-Rochon, E

2000-04-01

Egg cells were analysed cytologically during the female receptivity period in maize (Zea mays L., line A 188). Three classes of egg cell were distinguished: type A--small, non-vacuolated cells with a central nucleus; type B--larger cells with small vacuoles surrounding the perinuclear cytoplasm located in the middle of the cell; type C--big cells with a large apical vacuole and the mid-basal perinuclear cytoplasm. The less-dense cytoplasm of the vacuolated egg cells usually contained numerous cup- or bell-shaped mitochondria. The three egg types appear to correspond to three late stages of egg cell differentiation. The frequencies of each of the three egg types were monitored in developing maize ears before and after pollination. In young ears, with the silks just extending out of the husks, small A-type cells were found in about 86% of ovules. Their frequency decreased to about 58% at the optimum silk length, remained unchanged in non-pollinated ears, and fell to 16% at the end of the female receptivity period. However, after pollination and before fertilisation the frequency of these cells decreased to about 33%, and the larger vacuolated egg cells (types B and C) prevailed. At various stages of the receptivity period, pollination accelerated changes in the egg population, increasing the number of ovules bearing larger, vacuolated egg cells. Experiments with silk removal demonstrated that putative pollination signals act immediately after pollen deposition and are not species-specific.

Microcrustaceans (Branchipoda and Copepoda) of Wetland Impoundments on the Savannah River Site, Aiken, South Carolina

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

DeBiase, Adrienne E; Taylor, Barbara E

2005-09-21

The United States Department of Energy’s Savannah River Site (SRS) in Aiken, Allendale, and Barnwell Counties, South Carolina, contains an abundance of freshwater wetlands and impoundments. Four large impoundments, as well as several small, abandoned farm and mill ponds, and about 400 Carolina bays and other small, isolated depression wetland ponds are located within the 893 km2 area of the SRS. Crustaceans of the orders Branchiopoda and Copepoda are nearly ubiquitous in these water bodies. Although small in size, these organisms are often very abundant. They consequently play an important trophic role in freshwater food webs supporting fish, larval salamanders,more » larval insects, and numerous other animals, aquatic and terrestrial. This report provides an introduction to the free-living microcrustaceans of lentic water bodies on the SRS and a comprehensive list of species known to occur there. Occurrence patterns are summarized from three extensive survey studies, supplemented with other published and unpublished records. In lieu of a key, we provide a guide to taxonomic resources and notes on undescribed species. Taxa covered include the orders Cladocera, Anostraca, Laevicaudata, and Spinicaudata of the Subclass Branchiopoda and the Superorders Calanoida and Cyclopoida of Subclass Copepoda. Microcrustaceans of the Superorder Harpacticoida of the Subclass Copepoda and Subclass Ostracoda are also often present in lentic water bodies. They are excluded from this report because they have not received much study at the species level on the SRS.« less

Microcrustaceans (Branchiopoda and Copepoda) of Wetland Ponds and Impoundments on the Savannah River Site, Aiken, South Carolina

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

Adrienne E. DeBiase; Barbara E. Taylor

2005-09-21

The United States Department of Energy's Savannah River Site (SRS) in Aiken, Allendale, and Barnwell Counties, South Carolina, contains an abundance of freshwater wetlands and impoundments. Four large impoundments, as well as several small, abandoned farm and mill ponds, and about 400 Carolina bays and other small, isolated depression wetland ponds are located within the 893 km2 area of the SRS. Crustaceans of the orders Branchiopoda and Copepoda are nearly ubiquitous in these water bodies. Although small in size, these organisms are often very abundant. They consequently play an important trophic role in freshwater food webs supporting fish, larval salamanders,more » larval insects, and numerous other animals, aquatic and terrestrial. This report provides an introduction to the free-living microcrustaceans of lentic water bodies on the SRS and a comprehensive list of species known to occur there. Occurrence patterns are summarized from three extensive survey studies, supplemented with other published and unpublished records. In lieu of a key, we provide a guide to taxonomic resources and notes on undescribed species. Taxa covered include the orders Cladocera, Anostraca, Laevicaudata, and Spinicaudata of the Subclass Branchiopoda and the Superorders Calanoida and Cyclopoida of Subclass Copepoda. Microcrustaceans of the Superorder Harpacticoida of the Subclass Copepoda and Subclass Ostracoda are also often present in lentic water bodies. They are excluded from this report because they have not received much study at the species level on the SRS.« less

Improvements on Fresnel arrays for high contrast imaging

NASA Astrophysics Data System (ADS)

Wilhem, Roux; Laurent, Koechlin

2018-03-01

The Fresnel Diffractive Array Imager (FDAI) is based on a new optical concept for space telescopes, developed at Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France. For the visible and near-infrared it has already proven its performances in resolution and dynamic range. We propose it now for astrophysical applications in the ultraviolet with apertures from 6 to 30 meters, aimed at imaging in UV faint astrophysical sources close to bright ones, as well as other applications requiring high dynamic range. Of course the project needs first a probatory mission at small aperture to validate the concept in space. In collaboration with institutes in Spain and Russia, we will propose to board a small prototype of Fresnel imager on the International Space Station (ISS), with a program combining technical tests and astrophysical targets. The spectral domain should contain the Lyman- α line ( λ = 121 nm). As part of its preparation, we improve the Fresnel array design for a better Point Spread Function in UV, presently on a small laboratory prototype working at 260 nm. Moreover, we plan to validate a new optical design and chromatic correction adapted to UV. In this article we present the results of numerical propagations showing the improvement in dynamic range obtained by combining and adapting three methods : central obturation, optimization of the bars mesh holding the Fresnel rings, and orthogonal apodization. We briefly present the proposed astrophysical program of a probatory mission with such UV optics.

7 CFR 51.311 - Marking requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apples Marking Requirements...), grade, and the numerical count or minimum diameter of apples packed in a closed container shall be indicated on the container. For apple lots utilizing the combined diameter/weight designations for Red...

7 CFR 51.311 - Marking requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apples Marking Requirements...), grade, and the numerical count or minimum diameter of apples packed in a closed container shall be indicated on the container. For apple lots utilizing the combined diameter/weight designations for Red...

The laterality effect: myth or truth?

PubMed

Cohen Kadosh, Roi

2008-03-01

Tzelgov and colleagues [Tzelgov, J., Meyer, J., and Henik, A. (1992). Automatic and intentional processing of numerical information. Journal of Experimental Psychology: Learning, Memory and Cognition, 18, 166-179.], offered the existence of the laterality effect as a post-hoc explanation for their results. According to this effect, numbers are classified automatically as small/large versus a standard point under autonomous processing of numerical information. However, the genuinity of the laterality effect was never examined, or was confounded with the numerical distance effect. In the current study, I controlled the numerical distance effect and observed that the laterality effect does exist, and affects the processing of automatic numerical information. The current results suggest that the laterality effect should be taken into account when using paradigms that require automatic numerical processing such as Stroop-like or priming tasks.

The underlying number-space mapping among kindergarteners and its relation with early numerical abilities.

PubMed

Chan, Winnie Wai Lan; Wong, Terry Tin-Yau

2016-08-01

People map numbers onto space. The well-replicated SNARC (spatial-numerical association of response codes) effect indicates that people have a left-sided bias when responding to small numbers and a right-sided bias when responding to large numbers. This study examined whether such spatial codes were tagged to the ordinal or magnitude information of numbers among kindergarteners and whether it was related to early numerical abilities. Based on the traditional magnitude judgment task, we developed two variant tasks-namely the month judgment task and dot judgment task-to elicit ordinal and magnitude processing of numbers, respectively. Results showed that kindergarteners oriented small numbers toward the left side and large numbers toward the right side when processing the ordinal information of numbers in the month judgment task but not when processing the magnitude information in the number judgment task and dot judgment task, suggesting that the left-to-right spatial bias was probably tagged to the ordinal but not magnitude property of numbers. Moreover, the strength of the SNARC effect was not related to early numerical abilities. These findings have important implications for the early spatial representation of numbers and its role in numerical performance among kindergarteners. Copyright © 2016 Elsevier Inc. All rights reserved.

77 FR 22550 - Approval and Promulgation of Air Quality Implementation Plans; Illinois; Small Container...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-16

... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R05-OAR-2012-0073; FRL-9651-6] Approval and Promulgation of Air Quality Implementation Plans; Illinois; Small Container Exemption From VOC Coating Rules... Administrative Code by adding [[Page 22551

Efficient hybrid-symbolic methods for quantum mechanical calculations

NASA Astrophysics Data System (ADS)

Scott, T. C.; Zhang, Wenxing

2015-06-01

We present hybrid symbolic-numerical tools to generate optimized numerical code for rapid prototyping and fast numerical computation starting from a computer algebra system (CAS) and tailored to any given quantum mechanical problem. Although a major focus concerns the quantum chemistry methods of H. Nakatsuji which has yielded successful and very accurate eigensolutions for small atoms and molecules, the tools are general and may be applied to any basis set calculation with a variational principle applied to its linear and non-linear parameters.

Numerical solution of fluid-structure interaction represented by human vocal folds in airflow

NASA Astrophysics Data System (ADS)

Valášek, J.; Sváček, P.; Horáček, J.

2016-03-01

The paper deals with the human vocal folds vibration excited by the fluid flow. The vocal fold is modelled as an elastic body assuming small displacements and therefore linear elasticity theory is used. The viscous incompressible fluid flow is considered. For purpose of numerical solution the arbitrary Lagrangian-Euler method (ALE) is used. The whole problem is solved by the finite element method (FEM) based solver. Results of numerical experiments with different boundary conditions are presented.

Histological and morphological observations on tongue of Scincella tsinlingensis (Reptilia, Squamata, Scincidae).

PubMed

Yang, Chun; Wang, Limin

2016-01-01

The histology and morphology characteristics of the tongue in Scincella tsinlingensis were studied by light and electronic microscopy. Under light microscopy, the tongue consists of tip, lingual body and radix in sequence. Numerous lingual papillae widely distribute on the surface of the dorsal and ventral flanks in the tongue, in addition to some regions of the tip. The papillae's surface is covered with the epithelial layer. The lamina propria and dense connective tissue are distinct existing under the epithelial layer. There are many lingual glands spread over the lamina propria. Tongue muscle is developed and composed of distinct intrinsic muscle, hyoglossus and genioglossus. By scanning electron microscopy, at higher magnification, the epithelial cells of the dorsal surface in the divaricate tongue tips show numerous microvilli, micro-ridges and micro-pores. The surface of dorsal side of the papillae in lingual body is covered with abundant of micro-ridges and taste bud lacuna. On the surface of the papillae in radix, micro-facets and micro-ridges are compactly distributed, as well as scattered mucilage-pores. The lingual epithelium is divided into four layers observed by the transmission electron microscope. Cells of basal layer are irregularly elliptical in shape, with sparse organelles in the cytoplasm. The deep intermediate layer is not always distinct. Small numbers of organelles are scattered into the cytoplasm. The cells of the superficial intermediate layer gradually flatten, as do their nuclei. The cytoplasm contains many keratohyalin granules. Cell membranes are formed processes around cells and joined by abundant desmosomes to the cell membranes of adjacent cells. The cells located on the extreme free-surface side of the keratinized layer have fallen off. The basal lamina is intercalated between the basal layer and the lamina propria. The lamina propria of lingual body contains lingual gland. A large part of the cytoplasm is occupied by mucus granules which located in the distal part of the cell. The connective tissue contains myelinated nerve fibers, vessel and muscle cells. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Daugherty, W. L.

Destructive and non-destructive examinations have been performed on the components of shipping package 9975-02019 as part of a comprehensive SRS surveillance program for plutonium material stored in the K-Area Complex (KAC). During the field surveillance inspection of this package in KAC, two non-conforming conditions were noted: the axial gap of 1.577 inch exceeded the 1 inch maximum criterion, and two areas of dried glue residue were noted on the upper fiberboard subassembly. This package was subsequently transferred to SRNL for more detailed inspection and destructive examination. In addition to the conditions noted in KAC, the following conditions were noted: -more » Numerous small spots of corrosion were observed along the bottom edge of the drum. - In addition to the smeared glue residue on the upper fiberboard subassembly, there was also a small dark stain. - Mold was present on the side and bottom of the lower fiberboard subassembly. Dark stains from elevated moisture content were also present in these areas. - A dark spot with possible light corrosion was observed on the primary containment vessel flange, and corresponding rub marks were observed on the secondary containment vessel ID. - The fiberboard thermal conductivity in the radial orientation was above the specified range. When the test was repeated with slightly lower moisture content, the result was acceptable. The moisture content for both tests was within a range typical of other packages in storage. The observed conditions must be fully evaluated by KAC to ensure the safety function of the package is being maintained. Several factors can contribute to the concentration of moisture in the fiberboard, including higher than average initial moisture content, higher internal temperature (due to internal heat load and placement within the array of packages), and the creation of additional moisture as the fiberboard begins to degrade.« less

DASTCOM5: A Portable and Current Database of Asteroid and Comet Orbit Solutions

NASA Astrophysics Data System (ADS)

Giorgini, Jon D.; Chamberlin, Alan B.

2014-11-01

A portable direct-access database containing all NASA/JPL asteroid and comet orbit solutions, with the software to access it, is available for download (ftp://ssd.jpl.nasa.gov/pub/xfr/dastcom5.zip; unzip -ao dastcom5.zip). DASTCOM5 contains the latest heliocentric IAU76/J2000 ecliptic osculating orbital elements for all known asteroids and comets as determined by a least-squares best-fit to ground-based optical, spacecraft, and radar astrometric measurements. Other physical, dynamical, and covariance parameters are included when known. A total of 142 parameters per object are supported within DASTCOM5. This information is suitable for initializing high-precision numerical integrations, assessing orbit geometry, computing trajectory uncertainties, visual magnitude, and summarizing physical characteristics of the body. The DASTCOM5 distribution is updated as often as hourly to include newly discovered objects or orbit solution updates. It includes an ASCII index of objects that supports look-ups based on name, current or past designation, SPK ID, MPC packed-designations, or record number. DASTCOM5 is the database used by the NASA/JPL Horizons ephemeris system. It is a subset exported from a larger MySQL-based relational Small-Body Database ("SBDB") maintained at JPL. The DASTCOM5 distribution is intended for programmers comfortable with UNIX/LINUX/MacOSX command-line usage who need to develop stand-alone applications. The goal of the implementation is to provide small, fast, portable, and flexibly programmatic access to JPL comet and asteroid orbit solutions. The supplied software library, examples, and application programs have been verified under gfortran, Lahey, Intel, and Sun 32/64-bit Linux/UNIX FORTRAN compilers. A command-line tool ("dxlook") is provided to enable database access from shell or script environments.

An integrated approach to flood hazard assessment on alluvial fans using numerical modeling, field mapping, and remote sensing

USGS Publications Warehouse

Pelletier, J.D.; Mayer, L.; Pearthree, P.A.; House, P.K.; Demsey, K.A.; Klawon, J.K.; Vincent, K.R.

2005-01-01

Millions of people in the western United States live near the dynamic, distributary channel networks of alluvial fans where flood behavior is complex and poorly constrained. Here we test a new comprehensive approach to alluvial-fan flood hazard assessment that uses four complementary methods: two-dimensional raster-based hydraulic modeling, satellite-image change detection, fieldbased mapping of recent flood inundation, and surficial geologic mapping. Each of these methods provides spatial detail lacking in the standard method and each provides critical information for a comprehensive assessment. Our numerical model simultaneously solves the continuity equation and Manning's equation (Chow, 1959) using an implicit numerical method. It provides a robust numerical tool for predicting flood flows using the large, high-resolution Digital Elevation Models (DEMs) necessary to resolve the numerous small channels on the typical alluvial fan. Inundation extents and flow depths of historic floods can be reconstructed with the numerical model and validated against field- and satellite-based flood maps. A probabilistic flood hazard map can also be constructed by modeling multiple flood events with a range of specified discharges. This map can be used in conjunction with a surficial geologic map to further refine floodplain delineation on fans. To test the accuracy of the numerical model, we compared model predictions of flood inundation and flow depths against field- and satellite-based flood maps for two recent extreme events on the southern Tortolita and Harquahala piedmonts in Arizona. Model predictions match the field- and satellite-based maps closely. Probabilistic flood hazard maps based on the 10 yr, 100 yr, and maximum floods were also constructed for the study areas using stream gage records and paleoflood deposits. The resulting maps predict spatially complex flood hazards that strongly reflect small-scale topography and are consistent with surficial geology. In contrast, FEMA Flood Insurance Rate Maps (FIRMs) based on the FAN model predict uniformly high flood risk across the study areas without regard for small-scale topography and surficial geology. ?? 2005 Geological Society of America.

Numerical simulation of cavitating flows in shipbuilding

NASA Astrophysics Data System (ADS)

Bagaev, D.; Yegorov, S.; Lobachev, M.; Rudnichenko, A.; Taranov, A.

2018-05-01

The paper presents validation of numerical simulations of cavitating flows around different marine objects carried out at the Krylov State Research Centre (KSRC). Preliminary validation was done with reference to international test objects. The main part of the paper contains results of solving practical problems of ship propulsion design. The validation of numerical simulations by comparison with experimental data shows a good accuracy of the supercomputer technologies existing at Krylov State Research Centre for both hydrodynamic and cavitation characteristics prediction.

A tale of two neglected systems-structure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves.

PubMed

Botha, C E J

2013-01-01

There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5-7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer.

The three-dimensional structure of anosteocytic lamellated bone of fish.

PubMed

Atkins, Ayelet; Reznikov, Natalie; Ofer, Lior; Masic, Admir; Weiner, Steve; Shahar, Ron

2015-02-01

Fish represent the most diverse and numerous of the vertebrate clades. In contrast to the bones of all tetrapods and evolutionarily primitive fish, many of the evolutionarily more advanced fish have bones that do not contain osteocytes. Here we use a variety of imaging techniques to show that anosteocytic fish bone is composed of a sequence of planar layers containing mainly aligned collagen fibrils, in which the prevailing principal orientation progressively spirals. When the sequence of fibril orientations completes a rotation of around 180°, a thin layer of poorly oriented fibrils is present between it and the next layer. The thick layer of aligned fibrils and the thin layer of non-aligned fibrils constitute a lamella. Although both basic components of mammalian lamellar bone are found here as well, the arrangement is unique, and we therefore call this structure lamellated bone. We further show that the lamellae of anosteocytic fish bone contain an array of dense, small-diameter (1-4 μm) bundles of hypomineralized collagen fibrils that are oriented mostly orthogonal to the lamellar plane. Results of mechanical tests conducted on beams from anosteocytic fish bone and human cortical bone show that the fish bones are less stiff but much tougher than the human bones. We propose that the unique lamellar structure and the orthogonal hypomineralized collagen bundles are responsible for the unusual mechanical properties and mineral distribution in anosteocytic fish bone. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The molecular biology of environmental aromatic hydrocarbons

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

Weiss, S.B.

The induction of mutations in living cells by polycyclic aromatic hydrocarbons (PAH) has been recognized for many years. Although the mechanism for this occurrence has been examined by numerous investigators, the precise nature and type of mutations induced is still unclear. Earlier investigations of DNA damage and repair were primarily examined by the random alkylation of bacterial and mammalian DNAs, in vivo, using a variety of different PAH agents. This procedure is still used today. Though informative, such studies have not offered any explanation of the mechanism by which PAH agents induce carcinogenesis. We have attempted to examine the repairmore » of PAH-damaged DNA using small DNA oligomer constructs as targets for site-specific alkylation. DNA constructs containing a single BPDE alkylated site in each duplex strand were ligated into M13 RF DNA and used to transfect E. coli. Progeny M13 DNA was isolated from E. coli colonies grown on agar plates containing IPTG and Xgal. DNA sequence analysis of the isolated progeny M13 DNA, at the site of construct insertion, was found to contain large deletions and illegitimate recombinants. These sequence rearrangements occurred in either recA{sup +} or recA{sup -} host cells suggesting that SOS processing was not involved in the deletions and the recombinants observed. The mechanism by which BPDE induces illegitimate recombinants has not been resolved, however, it is possible that the closely spaced adducts activate the recombinant machinery in our DNA-damaged cells. 1 ref., 6 figs., 1 tab.« less

Comparing the Impact of Prescription Omega-3 Fatty Acid Products on Low-Density Lipoprotein Cholesterol.

PubMed

Sharp, Randall P; Gales, Barry J; Sirajuddin, Riaz

2018-04-01

Elevated levels of triglycerides are associated with pancreatitis and an increased risk of coronary heart disease. Numerous pharmacologic therapies are available to treat hypertriglyceridemia, including prescription omega-3 fatty acids, which reduce triglyceride levels by 20-50%. Available data indicate the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) may be beneficial for secondary prevention of coronary heart disease. Products containing DHA may increase low-density lipoprotein cholesterol (LDL-C) and, subsequently, coronary heart disease risk. We reviewed prescription omega-3 fatty acid products, of which two-omega-3 acid ethyl esters (OM3EE) and omega-3 carboxylic acid (OM3CA)-contain both DHA and EPA, whereas the other-icosapent ethyl (IPE)-contains EPA only. We identified three retrospective chart reviews and three case reports comparing IPE with OM3EE, whereas two studies compared IPE with placebo. We also reviewed the major studies of OM3EE versus placebo used to gain US FDA approval. LDL-C levels decreased or did not increase significantly in all available studies and case reports in patients receiving the IPE product, with the best data supporting a dose of 4 g per day. The majority of studies only included patients taking IPE concomitantly with statins, but limited data from one study using IPE monotherapy showed a small reduction in LDL-C. Many questions remain regarding IPE, including whether the product reduces cardiovascular events and mortality.

Effect of mitochondrial complex I inhibition on Fe-S cluster protein activity.

PubMed

Mena, Natalia P; Bulteau, Anne Laure; Salazar, Julio; Hirsch, Etienne C; Núñez, Marco T

2011-06-03

Iron-sulfur (Fe-S) clusters are small inorganic cofactors formed by tetrahedral coordination of iron atoms with sulfur groups. Present in numerous proteins, these clusters are involved in key biological processes such as electron transfer, metabolic and regulatory processes, DNA synthesis and repair and protein structure stabilization. Fe-S clusters are synthesized mainly in the mitochondrion, where they are directly incorporated into mitochondrial Fe-S cluster-containing proteins or exported for cytoplasmic and nuclear cluster-protein assembly. In this study, we tested the hypothesis that inhibition of mitochondrial complex I by rotenone decreases Fe-S cluster synthesis and cluster content and activity of Fe-S cluster-containing enzymes. Inhibition of complex I resulted in decreased activity of three Fe-S cluster-containing enzymes: mitochondrial and cytosolic aconitases and xanthine oxidase. In addition, the Fe-S cluster content of glutamine phosphoribosyl pyrophosphate amidotransferase and mitochondrial aconitase was dramatically decreased. The reduction in cytosolic aconitase activity was associated with an increase in iron regulatory protein (IRP) mRNA binding activity and with an increase in the cytoplasmic labile iron pool. Since IRP activity post-transcriptionally regulates the expression of iron import proteins, Fe-S cluster inhibition may result in a false iron deficiency signal. Given that inhibition of complex I and iron accumulation are hallmarks of idiopathic Parkinson's disease, the findings reported here may have relevance for understanding the pathophysiology of this disease. Copyright © 2011 Elsevier Inc. All rights reserved.

A tale of two neglected systems—structure and function of the thin- and thick-walled sieve tubes in monocotyledonous leaves

PubMed Central

Botha, C. E. J.

2013-01-01

There is a large body of information relating to the ontogeny, development and the vasculature of eudicotyledonous leaves. However, there is less information available concerning the vascular anatomy of monocotyledonous leaves. This is surprising, given that there are two uniquely different phloem systems present in large groups such as grasses and sedges. Monocotyledonous leaves contain marginal, large, intermediate, and small longitudinal veins that are interconnected by numerous transverse veins. The longitudinal veins contain two metaphloem sieve tube types, which, based upon their ontogeny and position within the phloem, are termed early (thin-walled) and late (thick-walled) sieve tubes. Early metaphloem comprises sieve tubes, companion cells and vascular parenchyma (VP) cells, whilst the late metaphloem, contains thick-walled sieve tubes (TSTs) that lack companion cells. TSTs are generally adjacent to, or no more than one cell removed from the metaxylem. Unlike thin-walled sieve tube (ST) -companion cell complexes, TSTs are connected to parenchyma by pore-plasmodesma units and are generally symplasmically isolated from the STs. This paper addresses key structural and functional differences between thin- and thick-walled sieve tubes and explores the unique advantages of alternate transport strategies that this 5–7 million years old dual system may offer. It would seem that these two systems may enhance, add to, or play a significant role in increasing the efficiency of solute retrieval as well as of assimilate transfer. PMID:23964280

The geologic structure of part of the southern Franklin Mountains, El Paso County, Texas

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

Smith, W.R.; Julian, F.E.

1993-02-01

The Franklin Mountains are a west tilted fault block mountain range which extends northwards from the city of El Paso, Texas. Geologic mapping in the southern portion of the Franklin Mountains has revealed many previously unrecognized structural complexities. Three large high-angle faults define the boundaries of map. Twenty lithologic units are present in the field area, including the southernmost Precambrian meta-sedimentary rocks in the Franklin Mountains (Lanoria Quartzite and Thunderbird group conglomerates). The area is dominated by Precambrian igneous rocks and lower Paleozoic carbonates, but Cenozoic ( ) intrusions are also recognized. Thin sections and rock slabs were used tomore » describe and identify many of the lithologic units. The Franklin Mountains are often referred to as a simple fault block mountain range related to the Rio Grande Rift. Three critical regions within the study area show that these mountains contain structural complexities. In critical area one, Precambrian granites and rhyolites are structurally juxtaposed, and several faults bisecting the area affect the Precambrian/Paleozoic fault contact. Critical area two contains multiple NNW-trending faults, three sills and a possible landslide. This area also shows depositional features related to an island of Precambrian rock exposed during deposition of the lower Paleozoic rocks. Critical area three contains numerous small faults which generally trend NNE. They appear to be splays off of one of the major faults bounding the area. Cenozoic kaolinite sills and mafic intrusion have filled many of the fault zones.« less

Improving Attachments of Remotely-Deployed Dorsal Fin-Mounted Tags: Tissue Structure, Hydrodynamics, in situ Performance, and Tagged-Animal Follow-up

DTIC Science & Technology

2014-09-30

TERM GOALS We recently developed small satellite-linked telemetry tags that are anchored with small attachment darts to the dorsal fins of small ...monitor the movements of numerous species not previously accessible because they were too large or difficult to capture safely, but too small for tags...cetaceans that provides the data needed to answer critical conservation and management questions without an adverse effect on the tagged animal. Therefore

77 FR 38006 - Approval and Promulgation of Implementation Plans; State of Iowa: Regional Haze

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-26

... Class I Areas'' contained one numerical error. Iowa's 2002 contribution to Voyagers should read 2.16... environmental effects, using practicable and legally permissible methods, under Executive Order 12898 (59 FR... a new entry (39) in numerical order to read as follows: Sec. 52.820 Identification of plan...

Stability of Nonlinear Principal Components Analysis: An Empirical Study Using the Balanced Bootstrap

ERIC Educational Resources Information Center

Linting, Marielle; Meulman, Jacqueline J.; Groenen, Patrick J. F.; van der Kooij, Anita J.

2007-01-01

Principal components analysis (PCA) is used to explore the structure of data sets containing linearly related numeric variables. Alternatively, nonlinear PCA can handle possibly nonlinearly related numeric as well as nonnumeric variables. For linear PCA, the stability of its solution can be established under the assumption of multivariate…

One-to-One Play Promotes Numerical Equivalence Concepts

ERIC Educational Resources Information Center

Mix, Kelly S.; Moore, Julie A.; Holcomb, Erin

2011-01-01

Young children spontaneously engage in a variety of one-to-one correspondence activities during play. The present study tested whether one of these activities--pairing objects with containers--supported the development of numerical equivalence judgments. Three-year-olds were given sets of toys to take home. In one condition, the toys were…

Computer-Numerical-Control and the EMCO Compact 5 Lathe.

ERIC Educational Resources Information Center

Mullen, Frank M.

This laboratory manual is intended for use in teaching computer-numerical-control (CNC) programming using the Emco Maier Compact 5 Lathe. Developed for use at the postsecondary level, this material contains a short introduction to CNC machine tools. This section covers CNC programs, CNC machine axes, and CNC coordinate systems. The following…

Scope Interpretation in First and Second Language Acquisition: Numeral Quantifiers and Negation

ERIC Educational Resources Information Center

Kwak, Hye-Young

2010-01-01

The present study investigates the interpretation of scopally ambiguous sentences containing a numeral quantifier and negation, such as (1) and (2), with a view to examining the interpretive preferences for Korean manifested by Korean-speaking children and adults, and the interpretive preferences for English manifested by Korean-speaking second…

Scilab and Maxima Environment: Towards Free Software in Numerical Analysis

ERIC Educational Resources Information Center

Mora, Angel; Galan, Jose Luis; Aguilera, Gabriel; Fernandez, Alvaro; Merida, Enrique; Rodriguez, Pedro

2010-01-01

In this work we will present the ScilabUMA environment we have developed as an alternative to Matlab. This environment connects Scilab (for numerical analysis) and Maxima (for symbolic computations). Furthermore, the developed interface is, in our opinion at least, as powerful as the interface of Matlab. (Contains 3 figures.)

Three-Dimensional Numerical Simulation on Triaxial Failure Mechanical Behavior of Rock-Like Specimen Containing Two Unparallel Fissures

NASA Astrophysics Data System (ADS)

Huang, Yan-Hua; Yang, Sheng-Qi; Zhao, Jian

2016-12-01

A three-dimensional particle flow code (PFC3D) was used for a systematic numerical simulation of the strength failure and cracking behavior of rock-like material specimens containing two unparallel fissures under conventional triaxial compression. The micro-parameters of the parallel bond model were first calibrated using the laboratory results of intact specimens and then validated from the experimental results of pre-fissured specimens under triaxial compression. Numerically simulated stress-strain curves, strength and deformation parameters and macro-failure modes of pre-fissured specimens were all in good agreement with the experimental results. The relationship between stress and the micro-crack numbers was summarized. Crack initiation, propagation and coalescence process of pre-fissured specimens were analyzed in detail. Finally, horizontal and vertical cross sections of numerical specimens were derived from PFC3D. A detailed analysis to reveal the internal damage behavior of rock under triaxial compression was carried out. The experimental and simulated results are expected to improve the understanding of the strength failure and cracking behavior of fractured rock under triaxial compression.

Numerical integration techniques for curved-element discretizations of molecule-solvent interfaces.

PubMed

Bardhan, Jaydeep P; Altman, Michael D; Willis, David J; Lippow, Shaun M; Tidor, Bruce; White, Jacob K

2007-07-07

Surface formulations of biophysical modeling problems offer attractive theoretical and computational properties. Numerical simulations based on these formulations usually begin with discretization of the surface under consideration; often, the surface is curved, possessing complicated structure and possibly singularities. Numerical simulations commonly are based on approximate, rather than exact, discretizations of these surfaces. To assess the strength of the dependence of simulation accuracy on the fidelity of surface representation, here methods were developed to model several important surface formulations using exact surface discretizations. Following and refining Zauhar's work [J. Comput.-Aided Mol. Des. 9, 149 (1995)], two classes of curved elements were defined that can exactly discretize the van der Waals, solvent-accessible, and solvent-excluded (molecular) surfaces. Numerical integration techniques are presented that can accurately evaluate nonsingular and singular integrals over these curved surfaces. After validating the exactness of the surface discretizations and demonstrating the correctness of the presented integration methods, a set of calculations are presented that compare the accuracy of approximate, planar-triangle-based discretizations and exact, curved-element-based simulations of surface-generalized-Born (sGB), surface-continuum van der Waals (scvdW), and boundary-element method (BEM) electrostatics problems. Results demonstrate that continuum electrostatic calculations with BEM using curved elements, piecewise-constant basis functions, and centroid collocation are nearly ten times more accurate than planar-triangle BEM for basis sets of comparable size. The sGB and scvdW calculations give exceptional accuracy even for the coarsest obtainable discretized surfaces. The extra accuracy is attributed to the exact representation of the solute-solvent interface; in contrast, commonly used planar-triangle discretizations can only offer improved approximations with increasing discretization and associated increases in computational resources. The results clearly demonstrate that the methods for approximate integration on an exact geometry are far more accurate than exact integration on an approximate geometry. A MATLAB implementation of the presented integration methods and sample data files containing curved-element discretizations of several small molecules are available online as supplemental material.

Numerical analysis of nuclear power plant structure subjected to aircraft crash

NASA Astrophysics Data System (ADS)

Saberi, Reza; Alinejad, Majid; Mahdavi, Mir Omid; Sepanloo, Kamran

2017-12-01

An aircraft crashing into a nuclear containment may induce a series of disasters related to containment capacity, including local penetration and perforation of the containment, intensive vibrations, and fire ignited after jet fuel leakage. In this study, structural safety of a reinforced concrete containment vessel (RCCV) has been studied against the direct hit of Airbus A320, Boeing 707-320 and Phantom F4 aircrafts. ABAQUS/explicit finite element code has been used to carry out the three-dimensional numerical simulations. The impact locations identified on the nuclear containment structure are mid height of containment, center of the cylindrical portion, junction of dome and cylinder, and over the cylindrical portion close to the foundation level. The loading of the aircraft has been assigned through the corresponding reaction-time response curve. The concrete damaged plasticity model was predicted to simulate the behavior of concrete while the behavior of steel reinforcement was incorporated using elastoplastic material model. Dynamic loading conditions were considered using dynamic increase factor. The mid height of containment and center of cylindrical portion have been found to experience most severe deformation against each aircraft crash. It has also been found that compression damage in concrete is not critical at none of the impact locations.

Vegetated treatment area effectiveness at reducing nutrient runoff from small swine operations in central Texas

USDA-ARS?s Scientific Manuscript database

Numerous modeling and field studies have evaluated the effectiveness of vegetative treatment systems in treating runoff from animal feeding operations; however, none have evaluated the effectiveness of vegetative treatment areas (VTA’s) receiving direct runoff from small swine operations during natu...

Are numbers grounded in a general magnitude processing system? A functional neuroimaging meta-analysis.

PubMed

Sokolowski, H Moriah; Fias, Wim; Bosah Ononye, Chuka; Ansari, Daniel

2017-10-01

It is currently debated whether numbers are processed using a number-specific system or a general magnitude processing system, also used for non-numerical magnitudes such as physical size, duration, or luminance. Activation likelihood estimation (ALE) was used to conduct the first quantitative meta-analysis of 93 empirical neuroimaging papers examining neural activation during numerical and non-numerical magnitude processing. Foci were compiled to generate probabilistic maps of activation for non-numerical magnitudes (e.g. physical size), symbolic numerical magnitudes (e.g. Arabic digits), and nonsymbolic numerical magnitudes (e.g. dot arrays). Conjunction analyses revealed overlapping activation for symbolic, nonsymbolic and non-numerical magnitudes in frontal and parietal lobes. Contrast analyses revealed specific activation in the left superior parietal lobule for symbolic numerical magnitudes. In contrast, small regions in the bilateral precuneus were specifically activated for nonsymbolic numerical magnitudes. No regions in the parietal lobes were activated for non-numerical magnitudes that were not also activated for numerical magnitudes. Therefore, numbers are processed using both a generalized magnitude system and format specific number regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

TECHNICAL GUIDANCE DOCUMENT: CONSTRUCTION QUALITY MANAGEMENT FOR REMEDIAL ACTION AND REMEDIAL DESIGN WASTE CONTAINMENT SYSTEMS

EPA Science Inventory

This Technical Guidance Document is intended to augment the numerous construction quality control and construction quality assurance (CQC and CQA) documents that are available far materials associated with waste containment systems developed for Superfund site remediation. In ge...

Numerical modeling of Stokes flows over a superhydrophobic surface containing gas bubbles

NASA Astrophysics Data System (ADS)

Ageev, A. I.; Golubkina, I. V.; Osiptsov, A. N.

2017-10-01

This paper continues the numerical modeling of Stokes flows near cavities of a superhydrophobic surface, occupied by gas bubbles, based on the Boundary Element Method (BEM). The aim of the present study is to estimate the friction reduction (pressure drop) in a microchannel with a bottom superhydrophobic surface, the texture of which is formed by a periodic system of striped rectangular microcavities containing compressible gas bubbles. The model proposed takes into account the streamwise variation of the bubble shift into the cavities, caused by the longitudinal pressure gradient in the channel flow. The solution for the macroscopic (averaged) flow in the microchannel, constructed using an effective slip boundary condition on the superhydrophobic bottom wall, is matched with the solution of the Stokes problem at the microscale of a single cavity containing a gas bubble. The 2D Stokes problems of fluid flow over single cavities containing curved phase interfaces with the condition of zero shear stress are reduced to the boundary integral equations which are solved using the BEM method.

In vitro platelet quality in storage containers used for pediatric transfusions.

PubMed

Weiss, Sandra; Scammell, Kenneth; Levin, Elena; Culibrk, Brankica; Zolfaghari, Sima; Gyöngyössy-Issa, Maria I C; Acker, Jason P

2012-08-01

The in vitro quality of small-volume platelet (PLT) aliquots for pediatric transfusions was assessed to determine the best practice approach. Small volumes (50 mL) of single apheresis PLT components (APCs), collected on either CaridianBCT Trima or Haemonetics MCS+ instruments, were aliquoted on Days 2, 3, 4, and 5 postcollection into Fenwal PL1240 or 4R2014 bags or 60-mL polypropylene syringes. Samples were tested for in vitro quality at their recommended expiry times (4 hr for 4R2014 bags and syringes or Day 5 for PL1240 bags). Assays included pH, CD62P expression, and metabolic measures. CD62P expression increased throughout storage in all containers. Among the small-volume containers, pH, pCO(2) , lactate, and bicarbonate varied considerably. Regardless of the day of aliquoting, pCO(2) was significantly higher and pO(2) was significantly lower in gas-impermeable syringes than other containers. No bacterial growth was detected in any sample. The quality of APCs aliquoted into small-volume containers meets regulatory requirements and is generally equivalent to that of full-volume APCs at expiry. © 2012 American Association of Blood Banks.

Modeling the effects of small turbulent scales on the drag force for particles below and above the Kolmogorov scale

NASA Astrophysics Data System (ADS)

Gorokhovski, Mikhael; Zamansky, Rémi

2018-03-01

Consistently with observations from recent experiments and DNS, we focus on the effects of strong velocity increments at small spatial scales for the simulation of the drag force on particles in high Reynolds number flows. In this paper, we decompose the instantaneous particle acceleration in its systematic and residual parts. The first part is given by the steady-drag force obtained from the large-scale energy-containing motions, explicitly resolved by the simulation, while the second denotes the random contribution due to small unresolved turbulent scales. This is in contrast with standard drag models in which the turbulent microstructures advected by the large-scale eddies are deemed to be filtered by the particle inertia. In our paper, the residual term is introduced as the particle acceleration conditionally averaged on the instantaneous dissipation rate along the particle path. The latter is modeled from a log-normal stochastic process with locally defined parameters obtained from the resolved field. The residual term is supplemented by an orientation model which is given by a random walk on the unit sphere. We propose specific models for particles with diameter smaller and larger size than the Kolmogorov scale. In the case of the small particles, the model is assessed by comparison with direct numerical simulation (DNS). Results showed that by introducing this modeling, the particle acceleration statistics from DNS is predicted fairly well, in contrast with the standard LES approach. For the particles bigger than the Kolmogorov scale, we propose a fluctuating particle response time, based on an eddy viscosity estimated at the particle scale. This model gives stretched tails of the particle acceleration distribution and dependence of its variance consistent with experiments.

Impedance Eduction in Large Ducts Containing Higher-Order Modes and Grazing Flow

NASA Technical Reports Server (NTRS)

Watson, Willie R.; Jones, Michael G.

2017-01-01

Impedance eduction test data are acquired in ducts with small and large cross-sectional areas at the NASA Langley Research Center. An improved data acquisition system in the large duct has resulted in increased control of the acoustic energy in source modes and more accurate resolution of higher-order duct modes compared to previous tests. Two impedance eduction methods that take advantage of the improved data acquisition to educe the liner impedance in grazing flow are presented. One method measures the axial propagation constant of a dominant mode in the liner test section (by implementing the Kumarsean and Tufts algorithm) and educes the impedance from an exact analytical expression. The second method solves numerically the convected Helmholtz equation and minimizes an objective function to obtain the liner impedance. The two methods are tested first on data synthesized from an exact mode solution and then on measured data. Results show that when the methods are applied to data acquired in the larger duct with a dominant higher-order mode, the same impedance spectra are educed as that obtained in the small duct where only the plane wave mode propagates. This result holds for each higher-order mode in the large duct provided that the higher-order mode is sufficiently attenuated by the liner.

Experimental Study on Properties of Methane Diffusion of Coal Block under Triaxial Compressive Stress

PubMed Central

Zhao, Hong-Bao

2014-01-01

Taking the standard size coal block samples defined by ISRM as research objects, both properties of methane diffusion of coal block under triaxial compressive stress and characteristic influences caused by methane pressure were systematically studied with thermo-fluid-solid coupling with triaxial servocontrolled seepage equipment of methane-containing coal. The result shows the methane diffusion property of coal block under triaxial compressive stress was shown in four-stage as follow, first is sharply reduce stage, second is hyperbolic reduce stage, third is close to a fixed value stage, fourth stage is 0. There is a special point making the reduced rate of characteristic curve of methane diffusion speed become sharply small; the influences of shape of methane diffusion speed characteristic curve caused by methane pressure are not obvious, which only is shown in numerical size of methane diffusion speed. Test time was extended required by appear of the special point makes the reduce rate of methane diffusion speed become sharply small. The fitting four-phase relation of methane diffusion of coal block under triaxial compressive stress was obtained, and the idea is proposed that influences of the fitting four-phase relation caused by methane pressure were only shown in value of fitting parameters. PMID:25531000

FILAMENT CHANNEL FORMATION VIA MAGNETIC HELICITY CONDENSATION

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

Knizhnik, K. J.; Antiochos, S. K.; DeVore, C. R.

2015-08-20

A major unexplained feature of the solar atmosphere is the accumulation of magnetic shear in the form of filament channels at photospheric polarity inversion lines (PILs). In addition to free energy, this shear represents magnetic helicity, which is conserved under reconnection. In this paper we address the problem of filament channel formation and show how filaments acquire their shear and magnetic helicity. The results of three-dimensional (3D) simulations using the Adaptively Refined Magnetohydrodynamics Solver are presented. Our findings support the model of filament channel formation by magnetic helicity condensation that was developed by Antiochos. We consider the small-scale photospheric twistingmore » of a quasi-potential flux system that is bounded by a PIL and contains a coronal hole (CH). The magnetic helicity injected by the small-scale photospheric motions is shown to inverse cascade up to the largest allowable scales that define the closed flux system: the PIL and the CH. This process produces field lines that are both sheared and smooth, and are sheared in opposite senses at the PIL and the CH. The accumulated helicity and shear flux are shown to be in excellent quantitative agreement with the helicity condensation model. We present a detailed analysis of the simulations, including comparisons of our analytical and numerical results, and discuss their implications for observations.« less

He behavior in Ni and Ni-based equiatomic solid solution alloy

NASA Astrophysics Data System (ADS)

Yan, Zhanfeng; Liu, Shaoshuai; Xia, Songqin; Zhang, Yong; Wang, Yugang; Yang, Tengfei

2018-07-01

In the current work, pure nickel (99.99 wt.%) and Ni-containing single phase equiatomic solid solution alloy Fe-Co-Cr-Ni were irradiated with 190 keV He ions at room temperature with different fluences and He behavior in both materials are compared. At 1 × 1017 cm-2, TEM observation reveals that only isolated and small He bubbles (1-2 nm) are formed in Fe-Co-Cr-Ni alloy while many small suspected "string"-like He bubbles are observed in nickel at the concentration peak region (5.5 at.%). When the fluence is increased to 5 × 1017 cm-2, average bubble size in nickel increases to ∼8 nm which is almost equal to that in Fe-Co-Cr-Ni, but a higher bubble density is observed in nickel. At the highest dose of 1 × 1018 cm-2, numerous surface blisters and exfoliations occur in nickel which are consistent with TEM observation, while the Fe-Co-Cr-Ni alloy only shows a slight surface blister. Bubble coarsening upon annealing at 500 °C (2 h) is observed at 5 × 1017 cm-2 in both alloys, but a significant larger bubble growth is observed in nickel, suggesting a relatively better resistance to He bubble growth for Fe-Co-Cr-Ni alloy.

Ultra Small Aperture Terminal for Ka-Band SATCOM

NASA Technical Reports Server (NTRS)

Acosta, Roberto; Reinhart, Richard; Lee, Richard; Simons, Rainee

1997-01-01

An ultra small aperture terminal (USAT) at Ka-band frequency has been developed by Lewis Research Center (LeRC) for data rates up to 1.5 Mbps in the transmit mode and 40 Mbps in receive mode. The terminal consists of a 35 cm diameter offset-fed parabolic antenna which is attached to a solid state power amplifier and low noise amplifier. A single down converter is used to convert the Ka-band frequency to 70 MHz intermediate frequency (IF). A variable rate (9.6 Kbps to 10 Mbps) commercial modem with a standard RS-449/RS-232 interface is used to provide point-to-point digital services. The terminal has been demonstrated numerous times using the Advanced Communications Technology Satellite (ACTS) and the 4.5 in Link Evaluation Terminal (LET) in Cleveland. A conceptual design for an advanced terminal has also been developed. This advanced USAT utilizes Microwave Monolithic Integrated Circuit (MMIC) and flat plate array technologies. This terminal will be self contained in a single package which will include a 1 watt solid state amplifier (SSPA), low noise amplifier (LNA) and a modem card located behind the aperture of the array. The advanced USAT will be light weight, transportable, low cost and easy to point to the satellite. This paper will introduce designs for the reflector based and array based USAT's.

An application of small-gap equations in sealing devices

NASA Technical Reports Server (NTRS)

Vionnet, Carlos A.; Heinrich, Juan C.

1993-01-01

The study of a thin, incompressible Newtonian fluid layer trapped between two almost parallel, sliding surfaces has been actively pursued in the last decades. This subject includes lubrication applications such as slider bearings or the sealing of non-pressurized fluids with rubber rotary shaft seals. In the present work we analyze numerically the flow of lubricant fluid through a micro-gap of sealing devices. The first stage of this study is carried out assuming that a 'small-gap' parameter delta attains an extreme value in the Navier-Stokes equations. The precise meaning of small-gap is achieved by the particular limit delta = 0 which, within the bounds of the hypotheses, predicts transport of lubricant through the sealed area by centrifugal instabilities. Numerical results obtained with the penalty function approximation in the finite element method are presented. In particular, the influence of inflow and outflow boundary conditions, and their impact in the simulated flow, are discussed.

PNS predictions for supersonic/hypersonic flows over finned missile configurations

NASA Technical Reports Server (NTRS)

Bhutta, Bilal A.; Lewis, Clark H.

1992-01-01

Finned missile design entails accurate and computationally fast numerical techniques for predicting viscous flows over complex lifting configurations at small to moderate angles of attack and over Mach 3 to 15; these flows are often characterized by strong embedded shocks, so that numerical algorithms are also required to capture embedded shocks. The recent real-gas Flux Vector Splitting technique is here extended to investigate the Mach 3 flow over a typical finned missile configuration with/without side fin deflections. Elliptic grid-generation techniques for Mach 15 flows are shown to be inadequate for Mach 3 flows over finned configurations and need to be modified. Fin-deflection studies indicate that even small amounts of missile fin deflection can substantially modify vehicle aerodynamics. This 3D parabolized Navier-Stokes scheme is also extended into an efficient embedded algorithm for studying small axially separated flow regions due to strong fin and control surface deflections.

An application of small-gap equations in sealing devices

NASA Astrophysics Data System (ADS)

Vionnet, Carlos A.; Heinrich, Juan C.

1993-11-01

The study of a thin, incompressible Newtonian fluid layer trapped between two almost parallel, sliding surfaces has been actively pursued in the last decades. This subject includes lubrication applications such as slider bearings or the sealing of non-pressurized fluids with rubber rotary shaft seals. In the present work we analyze numerically the flow of lubricant fluid through a micro-gap of sealing devices. The first stage of this study is carried out assuming that a 'small-gap' parameter delta attains an extreme value in the Navier-Stokes equations. The precise meaning of small-gap is achieved by the particular limit delta = 0 which, within the bounds of the hypotheses, predicts transport of lubricant through the sealed area by centrifugal instabilities. Numerical results obtained with the penalty function approximation in the finite element method are presented. In particular, the influence of inflow and outflow boundary conditions, and their impact in the simulated flow, are discussed.

A Jurassic Shock-Aftershock Earthquake Sequence Recorded by Small Clastic Pipes and Dikes within Dune Cross-Strata, Zion National Park, Utah

NASA Astrophysics Data System (ADS)

Loope, D. B.; Zlotnik, V. A.; Kettler, R. M.; Pederson, D. T.

2012-12-01

Eolian sandstones of south-central and southeast Utah contain large volumes of contorted cross-strata that have long been recognized as products of liquefaction caused by seismic shaking. Unlike most sites where Navajo Sandstone is exposed, in Zion National Park (southwestern Utah), the Navajo contains very, very few contorted strata. We have, however, mapped the distribution of more than 1,000 small-scale, vertical pipes and dikes in uncontorted cross-strata of the Navajo at two small study sites in Zion. Pipes are 2-5 cm in diameter and up to 3 m long; dikes are ~6 cm wide. Clusters of the water-escape structures lie directly above and below numerous, near-horizontal bounding surfaces. Dikes are restricted to the wind-ripple strata that lie above the bounding surfaces. Pipes are common both above and below the bounding surfaces. In map view, most pipes are arranged in lines. Near the bounding surfaces, pipes merge upward with shallow dikes trending parallel to the lines of pipes. Pipes formed in grainflows—homogeneous, well-sorted sand lacking cohesion. Dikes formed above the bounding surface, in more-cohesive, poorly sorted, wind-ripple strata. As liquefaction began, expansion of subsurface sand caused spreading within the unliquified (capping) beds near the land surface. Dikes intruded cracks in the wind-ripple strata, and pipes rose from the better-sorted sand to interdune surfaces, following trends of cracks. Because the wind-ripple strata had low cohesive strength, a depression formed around each rupture, and ejected sand built upward to a flat-topped surface rather than forming the cone of a classic sand volcano. In one 3 m2 portion of the map area, a cluster of about 20 pipes and dikes, many with truncated tops, record eight stratigraphically distinct seismic events. The large dunes that deposited the Navajo cross-strata likely moved ~1m/yr. When, in response to seismic shaking, a few liters of fluidized sand erupted onto the lowermost portion of the dune lee slope through a pipe, the erupted sand dried and was buried by climbing wind-ripple strata as the large dune continued to advance downwind. The mapped cluster recording eight distinct seismic events lies within thin-laminated sediment that was deposited by wind ripples during 1 m (~ 1 year) of southeastward dune migration. We conclude that the small pipes and dikes of our study sites are products of numerous >MM 5 earthquakes, some of which recurred at intervals of less than 2 months. We interpret one small cluster of pipes and dikes with well-defined upward terminations as a distinct shock-aftershock sequence. Because the largest modern earthquakes can produce surface liquefaction only up to about 175 km from their epicenters, the Jurassic epicenters must have been well within that distance. The tendency of modern plate boundaries to produce high-frequency aftershocks suggests that the epicenter for this Jurassic sequence lay to the southwest, within the plate boundary zone (not within continental rocks to the east). As eolian dunes steadily migrate over interdune surfaces underlain by water-saturated dune cross-strata, the thin, distinct laminae produced by the wind ripples that occupy dune toes can faithfully record high-frequency seismic events.

Periodic solutions of second-order nonlinear difference equations containing a small parameter. IV - Multi-discrete time method

NASA Technical Reports Server (NTRS)

Mickens, Ronald E.

1987-01-01

It is shown that a discrete multi-time method can be constructed to obtain approximations to the periodic solutions of a special class of second-order nonlinear difference equations containing a small parameter. Three examples illustrating the method are presented.

South Carolina Guide for Small Business Management.

ERIC Educational Resources Information Center

Vaughan, Ellen C.; Elliott, Ronald T.

This guide for small business management in South Carolina addresses the three domains of learning: psychomotor, cognitive, and affective. The guide contains suggestions for specific classroom activities for each domain. Each of the 11 units or tasks in the guide contains a competency statement followed by performance objectives, job-relevant…

48 CFR 52.219-25 - Small Disadvantaged Business Participation Program-Disadvantaged Status and Reporting.

Code of Federal Regulations, 2013 CFR

2013-10-01

... and is applicable if this contract contains small disadvantaged business (SDB) participation targets... requirement. If this contract contains SDB participation targets, the Contractor shall report on the participation of SDB concerns at contract completion, or as otherwise provided in this contract. Reporting may...

48 CFR 52.219-25 - Small Disadvantaged Business Participation Program-Disadvantaged Status and Reporting.

Code of Federal Regulations, 2014 CFR

2014-10-01

... and is applicable if this contract contains small disadvantaged business (SDB) participation targets... requirement. If this contract contains SDB participation targets, the Contractor shall report on the participation of SDB concerns at contract completion, or as otherwise provided in this contract. Reporting may...

77 FR 22497 - Approval and Promulgation of Air Quality Implementation Plans; Illinois; Small Container...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-16

... surface coating operations in the Chicago and Metro-East St. Louis 8-hour ozone nonattainment areas. These... available control technology (RACT) policy. DATES: This direct final rule will be effective June 15, 2012... ``small container exemption'' for pleasure craft surface coating operations. EPA previously approved...

Scattering by a slab containing randomly located cylinders: comparison between radiative transfer and electromagnetic simulation.

PubMed

Roux, L; Mareschal, P; Vukadinovic, N; Thibaud, J B; Greffet, J J

2001-02-01

This study is devoted to the examination of scattering of waves by a slab containing randomly located cylinders. For the first time to our knowledge, the complete transmission problem has been solved numerically. We have compared the radiative transfer theory with a numerical solution of the wave equation. We discuss the coherent effects, such as forward-scattering dip and backscattering enhancement. It is seen that the radiative transfer equation can be used with great accuracy even for optically thin systems whose geometric thickness is comparable with the wavelength. We have also shown the presence of dependent scattering.

Experimental and numerical investigations on reliability of air barrier on oil containment in flowing water.

PubMed

Lu, Jinshu; Xu, Zhenfeng; Xu, Song; Xie, Sensen; Wu, Haoxiao; Yang, Zhenbo; Liu, Xueqiang

2015-06-15

Air barriers have been recently developed and employed as a new type of oil containment boom. This paper presents systematic investigations on the reliability of air barriers on oil containments with the involvement of flowing water, which represents the commonly-seen shearing current in reality, by using both laboratory experiments and numerical simulations. Both the numerical and experimental investigations are carried out in a model scale. In the investigations, a submerged pipe with apertures is installed near the bottom of a tank to generate the air bubbles forming the air curtain; and, the shearing water flow is introduced by a narrow inlet near the mean free surface. The effects of the aperture configurations (including the size and the spacing of the aperture) and the location of the pipe on the effectiveness of the air barrier on preventing oil spreading are discussed in details with consideration of different air discharges and velocities of the flowing water. The research outcome provides a foundation for evaluating and/or improve the reliability of a air barrier on preventing spilled oil from further spreading. Copyright © 2015 Elsevier Ltd. All rights reserved.

Transportation of Hazardous Evidentiary Material.

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

Osborn, Douglas.

2005-06-01

This document describes the specimen and transportation containers currently available for use with hazardous and infectious materials. A detailed comparison of advantages, disadvantages, and costs of the different technologies is included. Short- and long-term recommendations are also provided.3 DraftDraftDraftExecutive SummaryThe Federal Bureau of Investigation's Hazardous Materials Response Unit currently has hazardous material transport containers for shipping 1-quart paint cans and small amounts of contaminated forensic evidence, but the containers may not be able to maintain their integrity under accident conditions or for some types of hazardous materials. This report provides guidance and recommendations on the availability of packages for themore » safe and secure transport of evidence consisting of or contaminated with hazardous chemicals or infectious materials. Only non-bulk containers were considered because these are appropriate for transport on small aircraft. This report will addresses packaging and transportation concerns for Hazardous Classes 3, 4, 5, 6, 8, and 9 materials. If the evidence is known or suspected of belonging to one of these Hazardous Classes, it must be packaged in accordance with the provisions of 49 CFR Part 173. The anthrax scare of several years ago, and less well publicized incidents involving unknown and uncharacterized substances, has required that suspicious substances be sent to appropriate analytical laboratories for analysis and characterization. Transportation of potentially hazardous or infectious material to an appropriate analytical laboratory requires transport containers that maintain both the biological and chemical integrity of the substance in question. As a rule, only relatively small quantities will be available for analysis. Appropriate transportation packaging is needed that will maintain the integrity of the substance, will not allow biological alteration, will not react chemically with the substance being shipped, and will otherwise maintain it as nearly as possible in its original condition.The recommendations provided are short-term solutions to the problems of shipping evidence, and have considered only currently commercially available containers. These containers may not be appropriate for all cases. Design, testing, and certification of new transportation containers would be necessary to provide a container appropriate for all cases.Table 1 provides a summary of the recommendations for each class of hazardous material.Table 1: Summary of RecommendationsContainerCost1-quart paint can with ArmlockTM seal ringLabelMaster(r)%242.90 eachHazard Class 3, 4, 5, 8, or 9 Small ContainersTC Hazardous Material Transport ContainerCurrently in Use4 DraftDraftDraftTable 1: Summary of Recommendations (continued)ContainerCost55-gallon open or closed-head steel drumsAll-Pak, Inc.%2458.28 - %2473.62 eachHazard Class 3, 4, 5, 8, or 9 Large Containers95-gallon poly overpack LabelMaster(r)%24194.50 each1-liter glass container with plastic coatingLabelMaster(r)%243.35 - %243.70 eachHazard Class 6 Division 6.1 Poisonous by Inhalation (PIH) Small ContainersTC Hazardous Material Transport ContainerCurrently in Use20 to 55-gallon PIH overpacksLabelMaster(r)%24142.50 - %24170.50 eachHazard Class 6 Division 6.1 Poisonous by Inhalation (PIH) Large Containers65 to 95-gallon poly overpacksLabelMaster(r)%24163.30 - %24194.50 each1-liter transparent containerCurrently in UseHazard Class 6 Division 6.2 Infectious Material Small ContainersInfectious Substance ShipperSource Packaging of NE, Inc.%24336.00 eachNone Commercially AvailableN/AHazard Class 6 Division 6.2 Infectious Material Large ContainersNone Commercially Available N/A5« less

Nuclear emulsion measurements of the astronauts' radiation exposure on the Apollo-Soyuz mission

NASA Technical Reports Server (NTRS)

Schaefer, H. J.; Sullivan, J. J.

1976-01-01

On the Apollo-Soyuz mission each astronaut carried one passive dosimeter containing nuclear photographic emulsions, plastic foils, TLD chips, and neutron-activation foils for recording radiation exposure. This report is limited to the presentation of data retrieved from nuclear emulsions. Protons, most of them trapped particles encountered in numerous passes through the South Atlantic Anomaly, contributed by far the largest share to the mission dose. Their linear energy transfer (LET) spectrum was established from track and grain counts in a G.5 emulsion which is used for medium and high energies, and from ender counts in a K.2 emulsion which is used for low energies. The total mission fluence of protons was found to be equivalent to a unidirectional beam of 448,500 square centimeters. The broad spectrum was broken down into small LET intervals, which allowed for the computation of absorbed doses and dose equivalents. The totals are 51 millirad and 74 millirem. Counts of disintegration stars in K.2 emulsion are incomplete at present. While a total of 467 stars were identified, counting their prong numbers is still in progress. It was concluded that the Apollo-Soyuz astronauts' radiation exposure as such did not contain anything out of the ordinary that would seem to require special attention.

Post-Newtonian N-body simulations

NASA Astrophysics Data System (ADS)

Aarseth, Sverre J.

2007-06-01

We report on the first fully consistent conventional cluster simulation which includes terms up to the third-order post-Newtonian approximation. Numerical problems for treating extremely energetic binaries orbiting a single massive object are circumvented by employing the special `wheel-spoke' regularization method of Zare which has not been used in large-N simulations before. Idealized models containing N = 1 × 105 particles of mass 1Msolar with a central black hole (BH) of 300Msolar have been studied on GRAPE-type computers. An initial half-mass radius of rh ~= 0.1 pc is sufficiently small to yield examples of relativistic coalescence. This is achieved by significant binary shrinkage within a density cusp environment, followed by the generation of extremely high eccentricities which are induced by Kozai cycles and/or resonant relaxation. More realistic models with white dwarfs and 10 times larger half-mass radii also show evidence of general relativity effects before disruption. An experimentation with the post-Newtonian terms suggests that reducing the time-scales for activating the different orders progressively may be justified for obtaining qualitatively correct solutions without aiming for precise predictions of the final gravitational radiation wave form. The results obtained suggest that the standard loss-cone arguments underestimate the swallowing rate in globular clusters containing a central BH.

The presence of PHB granules in cytoplasm protects non-halophilic bacterial cells against the harmful impact of hypertonic environments.

PubMed

Obruca, Stanislav; Sedlacek, Petr; Mravec, Filip; Krzyzanek, Vladislav; Nebesarova, Jana; Samek, Ota; Kucera, Dan; Benesova, Pavla; Hrubanova, Kamila; Milerova, Miluse; Marova, Ivana

2017-10-25

Numerous prokaryotes accumulate polyhydroxybutyrate (PHB) intracellularly as a storage material. It has also been proposed that PHB accumulation improves bacterial stress resistance. Cupriavidus necator and its PHB non-accumulating mutant were employed to investigate the protective role of PHB under hypertonic conditions. The presence of PHB granules enhanced survival of the bacteria after exposure to hypertonic conditions. Surprisingly, when coping with such conditions, the bacteria did not utilize PHB to harvest carbon or energy, suggesting that, in the osmotic upshock of C. necator, the protective mechanism of PHB granules is not associated with their hydrolysis. The presence of PHB granules influenced the overall properties of the cells, since challenged PHB-free cells underwent massive plasmolysis accompanied by damage to the cell membrane and the leakage of cytoplasm content, while no such effects were observed in PHB containing bacteria. Moreover, PHB granules demonstrated "liquid-like" properties indicating that they can partially repair and stabilize cell membranes by plugging small gaps formed during plasmolysis. In addition, the level of dehydration and changes in intracellular pH in osmotically challenged cells were less pronounced for PHB-containing cultures, demonstrating the important role of PHB for bacterial survival under hyperosmotic conditions. Copyright © 2017 Elsevier B.V. All rights reserved.