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1

Rheological Behaviour of Wheat Glutens at Small and Large Deformations. Comparison of Two Glutens Differing in Bread Making Potential  

Microsoft Academic Search

The rheological characteristics of hydrated cv. Obelisk and Katepwa glutens, with poor and good baking potential, respectively, were studied at small and large deformations. Dynamic (oscillatory) measurements at small deformations over a frequency range of 0·03 to 3 rad\\/s showed that cv. Katepwa gluten had a higher dynamic modulus and a lower loss tangent than cv. Obelisk gluten. Overmixing resulted

A. M. Janssen; T. van Vliet; J. M. Vereijken

1996-01-01

2

Modeling emf, Potential Difference, and Internal Resistance  

NSDL National Science Digital Library

Through class discussion and think-pair-share questions, this activity helps students come to understand the difference between emf and potential difference in electrical circuits. These concepts are broached within the context of internal resistance of batteries.

Maier, Steven

3

Testing reveals large differences in degasser performance  

SciTech Connect

A recent study conducted by Amoco Production Co. research indicates there is a significant difference in the degassing capabilities of oil field degassers. Studies were done with nine different degassers--three atmospheric and six vacuum. Results indicated that those degassers having high mud turbulence and impact, combined with spreading the mud over a large surface area and subjecting it to a vacuum, performed the best overall. Omitting or reducing any of these mechanisms resulted in poorer degassing capabilities. Vacuum appeared to be critical, especially in the heavier mud weights. Tests with 14.0 ppg water-based muds resulted in the vacuum degassers outperforming the atmospheric degassers. In the lighter mud, vacuum did not seem as important, but the top-rated vacuum units were still superior to all atmospheric units tested.

Bray, R.P.

1984-07-09

4

Potential Benefits Of Underride Guards In Large Truck Side Crashes  

Microsoft Academic Search

Objective: To evaluate the maximum potential for side underride guards (SUGs) to reduce passenger vehicle occupant fatalities and injuries in crashes with large trucks in the United States.Methods: Examination of the Large Truck Crash Causation Study (LTCCS) identified 206 crash events involving a passenger vehicle impact with the side of a large truck. Each case was evaluated to determine whether

Matthew L. Brumbelow

2012-01-01

5

Lichtheimia species exhibit differences in virulence potential.  

PubMed

Although the number of mucormycosis cases has increased during the last decades, little is known about the pathogenic potential of most mucoralean fungi. Lichtheimia species represent the second and third most common cause of mucormycosis in Europe and worldwide, respectively. To date only three of the five species of the genus have been found to be involved in mucormycosis, namely L. corymbifera, L. ramosa and L. ornata. However, it is not clear whether the clinical situation reflects differences in virulence between the species of Lichtheimia or whether other factors are responsible. In this study the virulence of 46 strains of all five species of Lichtheimia was investigated in chicken embryos. Additionally, strains of the closest-related genus Dichotomocladium were tested. Full virulence was restricted to the clinically relevant species while all strains of L. hyalospora, L. sphaerocystis and Dichotomocladium species were attenuated. Although virulence differences were present in the clinically relevant species, no connection between origin (environmental vs clinical) or phylogenetic position within the species was observed. Physiological studies revealed no clear connection of stress resistance and carbon source utilization with the virulence of the strains. Slower growth at 37°C might explain low virulence of L. hyalospora, L. spaherocystis and Dichotomocladium; however, similarly slow growing strains of L. ornata were fully virulent. Thus, additional factors or a complex interplay of factors determines the virulence of strains. Our data suggest that the clinical situation in fact reflects different virulence potentials in the Lichtheimiaceae. PMID:22911715

Schwartze, Volker U; Hoffmann, Kerstin; Nyilasi, Ildikó; Papp, Tamás; Vágvölgyi, Csaba; de Hoog, Sybren; Voigt, Kerstin; Jacobsen, Ilse D

2012-01-01

6

Lichtheimia Species Exhibit Differences in Virulence Potential  

PubMed Central

Although the number of mucormycosis cases has increased during the last decades, little is known about the pathogenic potential of most mucoralean fungi. Lichtheimia species represent the second and third most common cause of mucormycosis in Europe and worldwide, respectively. To date only three of the five species of the genus have been found to be involved in mucormycosis, namely L. corymbifera, L. ramosa and L. ornata. However, it is not clear whether the clinical situation reflects differences in virulence between the species of Lichtheimia or whether other factors are responsible. In this study the virulence of 46 strains of all five species of Lichtheimia was investigated in chicken embryos. Additionally, strains of the closest-related genus Dichotomocladium were tested. Full virulence was restricted to the clinically relevant species while all strains of L. hyalospora, L. sphaerocystis and Dichotomocladium species were attenuated. Although virulence differences were present in the clinically relevant species, no connection between origin (environmental vs clinical) or phylogenetic position within the species was observed. Physiological studies revealed no clear connection of stress resistance and carbon source utilization with the virulence of the strains. Slower growth at 37°C might explain low virulence of L. hyalospora, L. spaherocystis and Dichotomocladium; however, similarly slow growing strains of L. ornata were fully virulent. Thus, additional factors or a complex interplay of factors determines the virulence of strains. Our data suggest that the clinical situation in fact reflects different virulence potentials in the Lichtheimiaceae.

Schwartze, Volker U.; Hoffmann, Kerstin; Nyilasi, Ildiko; Papp, Tamas; Vagvolgyi, Csaba; de Hoog, Sybren; Voigt, Kerstin; Jacobsen, Ilse D.

2012-01-01

7

Resolvent estimates for perturbations by large magnetic potentials  

NASA Astrophysics Data System (ADS)

We prove optimal high-frequency resolvent estimates for self-adjoint operators of the form G = -? + ib(x) · ? + i? · b(x) + V(x) on L2(Rn), n ? 3, where b(x) and V(x) are large magnetic and electric potentials, respectively. No continuity of the magnetic potential is assumed.

Cardoso, Fernando; Cuevas, Claudio; Vodev, Georgi

2014-02-01

8

Auditory sexual difference in the large odorous frog Odorrana graminea.  

PubMed

Acoustic communication is an important behavior in frog courtship. Male and female frogs of most species, except the concave-eared torrent frog Odorrana tormota, have largely similar audiograms. The large odorous frogs (Odorrana graminea) are sympatric with O. tormota, but have no ear canals. The difference in hearing between two sexes of the frog is unknown. We recorded auditory evoked near-field potentials and single-unit responses from the auditory midbrain (the torus semicircularis) to determine auditory frequency sensitivity and threshold. The results show that males have the upper frequency limit at 24 kHz and females have the upper limit at 16 kHz. The more sensitive frequency range is 3-15 kHz for males and 1-8 kHz for females. Males have the minimum threshold at 11 kHz (58 dB SPL), higher about 5 dB than that at 3 kHz for females. The best excitatory frequencies of single units are mostly between 3 and 5 kHz in females and at 7-8 kHz in males. The underlying mechanism of auditory sexual differences is discussed. PMID:24510208

Liu, Wei-Rong; Shen, Jun-Xian; Zhang, Yu-Jiao; Xu, Zhi-Min; Qi, Zhi; Xue, Mao-Qiang

2014-04-01

9

Lichtheimia Species Exhibit Differences in Virulence Potential  

Microsoft Academic Search

Although the number of mucormycosis cases has increased during the last decades, little is known about the pathogenic potential of most mucoralean fungi. Lichtheimia species represent the second and third most common cause of mucormycosis in Europe and worldwide, respectively. To date only three of the five species of the genus have been found to be involved in mucormycosis, namely

Volker U. Schwartze; Kerstin Hoffmann; Ildikó Nyilasi; Tamás Papp; Csaba Vágvölgyi; Sybren de Hoog; Kerstin Voigt; Ilse D. Jacobsen

2012-01-01

10

Individual Skill Differences and Large-Scale Environmental Learning  

ERIC Educational Resources Information Center

Spatial skills are known to vary widely among normal individuals. This project was designed to address whether these individual differences are differentially related to large-scale environmental learning from route (ground-level) and survey (aerial) perspectives. Participants learned two virtual environments (route and survey) with limited…

Fields, Alexa W.; Shelton, Amy L.

2006-01-01

11

Mixing device for materials with large density differences  

DOEpatents

An auger-tube pump mixing device is disclosed for mixing materials with large density differences while maintaining low stirring RPM and low power consumption. The mixing device minimizes the formation of vortexes and minimizes the incorporation of small bubbles in the liquid during mixing. By avoiding the creation of a vortex the device provides efficient stirring of full containers without spillage over the edge. Also, the device solves the problem of effective mixing in vessels where the liquid height is large compared to the diameter. Because of the gentle stirring or mixing by the device, it has application for biomedical uses where cell damage is to be avoided. 2 figs.

Gregg, D.W.

1994-08-16

12

Jaw and Long Bone Marrows Have a Different Osteoclastogenic Potential  

PubMed Central

Osteoclasts, the multinucleated bone-resorbing cells, arise through fusion of precursors from the myeloid lineage. However, not all osteoclasts are alike; osteoclasts at different bone sites appear to differ in numerous respects. We investigated whether bone marrow cells obtained from jaw and long bone differed in their osteoclastogenic potential. Bone marrow cells from murine mandible and tibiae were isolated and cultured for 4 and 6 days on plastic or 6 and 10 days on dentin. Osteoclastogenesis was assessed by counting the number of TRAP+ multinucleated cells. Bone marrow cell composition was analyzed by FACS. The expression of osteoclast- and osteoclastogenesis-related genes was studied by qPCR. TRAP activity and resorptive activity of osteoclasts were measured by absorbance and morphometric analyses, respectively. At day 4 more osteoclasts were formed in long bone cultures than in jaw cultures. At day 6 the difference in number was no longer observed. The jaw cultures, however, contained more large osteoclasts on plastic and on dentin. Long bone marrow contained more osteoclast precursors, in particular the myeloid blasts, and qPCR revealed that the RANKL:OPG ratio was higher in long bone cultures. TRAP expression was higher for the long bone cultures on dentin. Although jaw osteoclasts were larger than long bone osteoclasts, no differences were found between their resorptive activities. In conclusion, bone marrow cells from different skeletal locations (jaw and long bone) have different dynamics of osteoclastogenesis. We propose that this is primarily due to differences in the cellular composition of the bone site-specific marrow.

de Souza Faloni, Ana Paula; Schoenmaker, Ton; Azari, Azin; Katchburian, Eduardo; Cerri, Paulo S.; de Vries, Teun J.

2010-01-01

13

Central ridge of Newfoundland: Little explored, potential large  

SciTech Connect

The Central ridge on the northeastern Grand Banks off Newfoundland represents a large area with known hydrocarbon accumulations and the potential for giant fields. It covers some 17,000 sq km with water less than 400 m deep. The first major hydrocarbon discovery on the Newfoundland Grand Banks is giant Hibernia field in the Jeanne d'Arc basin. Hibernia field, discovered in 1979, has reserves of 666 million bbl and is due onstream in 1997. Since Hibernia, 14 other discoveries have been made on the Grand Banks, with three on the Central ridge. Oil was first discovered on Central Ridge in 1980 with the Mobil et al. South Tempest G-88 well. In 1982 gas was discovered with the Mobil et al. North Dana I-43 well 30 km northeast of the earlier discovery. In 1983 gas and condensate were discovered with the Husky-Bow Valley et al. Trave E-87 well 20 km south of the South Tempest well. These discoveries are held under significant discovery licenses and an additional 2,400 sq km are held under exploration licenses. The paper discusses the history of the basin, the reservoir source traps, and the basin potential.

Silva, N.R. De (Canada-Newfoundland Offshore Petroleum Board, Newfoundland, St. Johns (Canada))

1993-10-25

14

The effects of interaction between large and small diameter fiber systems on the somatosensory evoked potential.  

PubMed

The effect of interaction between large and small diameter fiber systems on the somatosensory evoked potential (SEP) was studied in anesthetized cats. Activation of large diameter fibers of the peroneal or radial nerves eliminates the late components of the SEP produced by stimulation of all fibers in the contralateral median or radial nerves. The inhibitory effects of a selective conditioning stimulus to the large diameter fibers of the peroneal nerve on the radial nerve evoked SEP was eliminated by bilateral transection of the dorsal column and spino-cervical tracts. However, interaction could still be obtained following transection when both large and small diameter fibers in the peroneal nerve were stimulated. The results of this study support the hypothesis that a correlation exists between activity in different fiber groups in afferent nerves, their conduction pathways through the cord, and the components of the cortical evoked potential. PMID:78821

Katz, S; Martin, H F; Blackburn, J G

1978-07-01

15

A Methodology for Estimating Large-Customer Demand Response MarketPotential  

SciTech Connect

Demand response (DR) is increasingly recognized as an essential ingredient to well-functioning electricity markets. DR market potential studies can answer questions about the amount of DR available in a given area and from which market segments. Several recent DR market potential studies have been conducted, most adapting techniques used to estimate energy-efficiency (EE) potential. In this scoping study, we: reviewed and categorized seven recent DR market potential studies; recommended a methodology for estimating DR market potential for large, non-residential utility customers that uses price elasticities to account for behavior and prices; compiled participation rates and elasticity values from six DR options offered to large customers in recent years, and demonstrated our recommended methodology with large customer market potential scenarios at an illustrative Northeastern utility. We observe that EE and DR have several important differences that argue for an elasticity approach for large-customer DR options that rely on customer-initiated response to prices, rather than the engineering approaches typical of EE potential studies. Base-case estimates suggest that offering DR options to large, non-residential customers results in 1-3% reductions in their class peak demand in response to prices or incentive payments of $500/MWh. Participation rates (i.e., enrollment in voluntary DR programs or acceptance of default hourly pricing) have the greatest influence on DR impacts of all factors studied, yet are the least well understood. Elasticity refinements to reflect the impact of enabling technologies and response at high prices provide more accurate market potential estimates, particularly when arc elasticities (rather than substitution elasticities) are estimated.

Goldman, Charles; Hopper, Nicole; Bharvirkar, Ranjit; Neenan,Bernie; Cappers,Peter

2007-08-01

16

Assessing carbon dynamics in semiarid ecosystems : Balancing potential gains with potential large rapid losses  

SciTech Connect

Photosynthesis and respiration are the largest fluxes into and out of the biosphere (Molles 1999). Consequently, small changes in these fluxes can potentially produce large changes in the storage of carbon in the biosphere. Terrestrial carbon fluxes account for more than half of the carbon transferred between the atmosphere and the earth's surface (about 120 GigaTons/year), and current stores of carbon in terrestrial ecosystem are estimated at 2060 GigaTons. Increasing attention is being focused on the role of managing and sequestering carbon in the terrestrial biosphere as a means for addressing global climate change (IGBP, 1998; U.S. Department of Energy, 1999). Terrestrial ecosystems are widely recognized as a major biological scrubber for atmosphereic CO{sub 2} and their ability to finction as such can be increased significantly over the next 25 years through careful manipulation. The potential for terrestrial carbon gains has been the subject of much attention (Dixon et al., 1994; Masera et al. 1997; Cao and Woodward, 1998; DeLucia et al. 1999). In contrast to other strategies for reducing net carbon emissions, terrestrial sequestration has the potential for rapid implementation. Strategies that focus on soil carbon are likely to be effective because in addition to being a storage pool of carbon, soil carbon also improves site productivity through improving soil quality (e.g., water retention and nutrient availability). The carbon pool in soils is immense and highly dynamic. The flux of carbon into and out of soils is one of the largest uncertainties in the total mass balance of global carbon (NRC, 1999; La1 et al., 1998; Cambardella, 1998). Reducing these uncertainties is key to developing carbon sequestration strategies. Soil carbon pools have been greatly depleted over recent centuries, and there is potential to increase storage of carbon in these soils through effective land management. Whereas carbon in vegetation can be managed directly through land use, carbon in soils generally must be managed indirectly through manipulation of vegetation and nutrients. Land management as well as climate changes have the potential to increase soil carbon, but also could trigger large soil carbon losses. Recently, the importance of accounting for countervailing losses in assessing potential amounts of terrestrial carbon that can be sequestered has been highlighted (Schlesinger, 1999; Walker et al., 1999). Realistic assessment of terrestrial carbon sequestration strategies must consider net results of an applied strategy, not simply projected carbon gains. In addition, large, rapid losses of carbon resulting from carbon management strategies could exacerbate the global warming rather than mitigating it. Such potential losses include rapid loss of carbon in vegetation due to fire and rapid loss of soil carbon triggered by reductions in ground cover (e.g., fire, drought). Therefore, strategies for terrestrial carbon sequestration must determine how to increase terrestrial carbon while minimizing the risk of large-scale catastrophic losses. Our objectives in this paper are to (1) highlight approaches that are being considered in terms of terrestrial carbon sequestration, (2) highlight case studies for which large losses of carbon may occur, and (3) suggest future directions and application for terrestrial carbon sequestration.

Breshears, D. D. (David D.); Ebinger, M. H. (Michael H.); Unkefer, P. J. (Pat J.)

2001-01-01

17

Thermoelectric properties and efficiency measurements under large temperature differences.  

PubMed

The maximum efficiency of a thermoelectric generator is determined by the material's dimensionless figure of merit ZT. Real thermoelectric material properties are highly temperature dependent and are often measured individually using multiple measurement tools on different samples. As a result, reported ZT values have large uncertainties. In this work we present an experimental technique that eliminates some of these uncertainties. We measure the Seebeck coefficient, electrical conductivity, and thermal conductivity of a single element or leg, as well as the conversion efficiency, under a large temperature difference of 2-160 degrees C. The advantages of this technique include (1) the thermoelectric leg is mounted only once and all measurements are in the same direction and (2) the measured properties are corroborated by efficiency measurements. The directly measured power and efficiency are compared to the values calculated from the measured properties and agree within 0.4% and 2%, respectively. The realistic testing conditions of this technique make it ideal for material characterization prior to implementation in a real thermoelectric generator. PMID:19791947

Muto, A; Kraemer, D; Hao, Q; Ren, Z F; Chen, G

2009-09-01

18

High-Precision Finite Difference Method Calculations of Electrostatic Potential  

Microsoft Academic Search

The finite difference method (FDM) is one of the standard methods [1–7] for electrostatic potential calculations in nonanalytic\\u000a geometries. In this technique, typically, a single, square mesh is overlaid upon the geometry and subsequently relaxed. During\\u000a the relaxation, the potentials at successive points within the mesh are evaluated using an appropriate algorithm, itself being\\u000a a function of the potentials at

David Edwards

19

Possibility of large lifetime differences in neutral B meson systems  

SciTech Connect

We investigate new physics models that can increase the lifetime differences in the B{sub q}-B{sub q} systems (q=d, s) above their standard model values. If both B{sub q} as well as B{sub q} can decay to a final state through flavor dependent new physics interactions, the so-called Grossman bound may be evaded. As examples, we consider the scalar leptoquark model and {lambda}{sup ''}-type R-parity violating supersymmetry. We find that models with a scalar leptoquark can enhance {delta}{gamma}{sub s}/{gamma}{sub s} all the way up to its experimental upper bound and {delta}{gamma}{sub d}/{gamma}{sub d} to as much as {approx}2.5%, at the same time allowing the CP violating phase {beta}{sub s} to vary between -45 deg. and 20 deg. R-parity violating supersymmetry models cannot enhance the lifetime differences significantly, but can enhance the value of {beta}{sub s} up to {approx}{+-}20 deg. This may bring the values of {delta}{gamma}{sub q}/{gamma}{sub q} as well as {beta}{sub s} within the measurement capabilities of B factories and the B physics experiment at the Large Hadron Collider (LHCb). We also obtain bounds on combinations of these new physics couplings, and predict enhanced branching ratios of B{sub s/d}{yields}{tau}{sup +}{tau}{sup -}.

Dighe, Amol [Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai 400005 (India); Kundu, Anirban; Nandi, Soumitra [Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700009 (India)

2007-09-01

20

Information Processing Potentials in Large-Scale Operations.  

National Technical Information Service (NTIS)

In the study of large organizations, the information, communication, and governing processes have been extremely difficult to formulate. Towards such a formulation, the strategy of the Leviathan studies has been to pursue two lines of attack--theoretical ...

B. K. Rome S. C. Rome

1966-01-01

21

Historically Large Geomagnetic Storms and Potential Electric Power Grid Impacts  

Microsoft Academic Search

While recent work has been done to examine the possible Dst Intensity of historically large geomagnetic storms, the impacts caused to modern day electric power grids from these storms occurs due to rapid rate-of-change of regional geomagnetic fields which in most cases are driven by large ionospheric electrojet current intensifications. These temporally and spatially dynamic disturbance morphologies are not well-characterized

J. G. Kappenman

2004-01-01

22

Testing CIELAB-based color-difference formulae using large color differences  

Microsoft Academic Search

Three advanced CIELAB-based color-difference formulae, CMC, CIE94, and CIEDE2000, together with the basic CIELAB equation,\\u000a were tested using large color-difference visual data (maximum average size was 12 CIELAB ?E units) produced in this study.\\u000a The color-difference comparison experiment was carried out at CIE Gray and Blue centers by a panel of 6 normal color-vision\\u000a observers using CRT-generated stimuli based on

Haisong Xu; Hirohisa Yaguchi; Satoshi Shioiri

2001-01-01

23

Discussion of the potential and limitations of direct and large-eddy simulations  

NASA Technical Reports Server (NTRS)

The full text of the discussion paper presented at the Whither Turbulence Workshop on the potential and limitations of direct and large-eddy simulations is provided. Particular emphasis is placed on discussing the role of numerics and mathematical theory in direct simulations of both compressible and incompressible flows. A variety of unresolved issues with large-eddy simulations such as their implementation in high-order finite difference codes, problems with defiltering, and modifications to accommodate integrations to solid boundaries are elaborated on. These as well as other points are discussed in detail along with the authors' views concerning the prospects for future research.

Hussaini, M. Y.; Speziale, Charles G.; Zang, Thomas A.

1989-01-01

24

Germination Responses to Water Potential in Neotropical Pioneers Suggest Large-seeded Species Take More Risks  

PubMed Central

Background and Aims In neotropical forests, very small-seeded pioneer species (<0·1 mg seed mass) recruit preferentially in small tree fall gaps and at gap edges, but large-seeded pioneers do not. Since water availability is related to gap size, these differences in microsite preference may reflect in part species-specific differences in germination at reduced water potentials. Methods For 14 neotropical pioneer species, the hypothesis is tested that small-seeded species, with shallow initial rooting depths, reduce the risks associated with desiccation by germinating more slowly and at higher water potentials than large-seeded species. Key Results Germination occurred both more quickly and at lower water potentials with increasing seed mass. For example, Ochroma pyramidale (seed mass 5·5 mg) had a time to 50 % germination (T50) of 2·8 d and a median base potential for germination (?b50) of ?1·8 MPa while Clidemia quinquenervia (seed mass 0·017 mg) had a T50 of 17·6 d and ?b50 of ?1·1 MPa. Conclusions These data suggest that small-seeded species germinate only in comparatively moist microsites, such as small canopy gaps, which may reduce the risk of drought-induced mortality. Conversely, large-seeded species are able to germinate in the drier environment of large gaps, where they benefit by enhanced seedling growth in a high irradiance environment. The positive association of seed size and canopy gap size for optimal seedling establishment is maintained by differential germination responses to soil water availability coupled with the scaling of radicle growth rate and seed size, which collectively confer greater drought tolerance on large-seeded species.

Daws, Matthew I.; Crabtree, Lora M.; Dalling, James W.; Mullins, Christopher E.; Burslem, David F. R. P.

2008-01-01

25

A Large Potential Methane Source—Natural Gas Hydrates  

Microsoft Academic Search

Natural gas, essentially methane, can be obtained from natural gas hydrate (NGH). NGH reserves are difficult to pinpoint in the subsurface, but large sources have been identified by seismic reflection. This is particularly so below the sea floor near continental shelf plates in the oceans deeper than 300 m as NGH is stable at 4°C and 50 bar pressure. When

R. A. Dawe; S. Thomas

2007-01-01

26

On hemispheric differences in evoked potentials to speech stimuli  

NASA Technical Reports Server (NTRS)

Confirmation is provided for the belief that evoked potentials may reflect differences in hemispheric functioning that are marginal at best. Subjects were right-handed and audiologically normal men and women, and responses were recorded using standard EEG techniques. Subjects were instructed to listen for the targets while laying in a darkened sound booth. Different stimuli, speech and tone signals, were used. Speech sounds were shown to evoke a response pattern that resembles that to tone or clicks. Analysis of variances on peak amplitude and latency measures showed no significant differences between hemispheres, however, a Wilcoxon test showed significant differences in hemispheres for certain target tasks.

Galambos, R.; Benson, P.; Smith, T. S.; Schulman-Galambos, C.; Osier, H.

1975-01-01

27

One Week Before the Election, Nader's Potential Impact Looms Large  

NSDL National Science Digital Library

Over the weekend, Democratic Vice-Presidential candidate Joe Lieberman urged Nader-supporters to consider that a vote for Nader could well end up giving George W. Bush the White House. Lieberman was echoing the thoughts of a growing number of liberals, including Gloria Steinem and the presidents of the Sierra Club and the National Organization for Women, who are stumping for Gore in selected toss-up states. Such concerns are justified by recent polling data that give Nader sufficient support in states like Washington, Oregon, Wisconsin, Minnesota, and Michigan to tip the balance from Gore to Bush, assuming, as most polls show, that Nader draws more from potential Gore voters than potential Bush voters. In this same vein, some earlier prominent, Nader-led activists, dubbed "Nader's Raiders," have shifted their loyalties and, at the prospect of a Bush presidency, turned to Gore. But the Green Party's candidate is himself undeterred, stating frankly on ABC News's This Week Sunday that "if he [Gore] cannot defeat the bumbling Texas governor with that horrific record, what good is he? It should be a slam dunk." Analysts are divided over whether would-be Nader voters will break at the last minute for Gore, accepting the thinking of democratic leaders that only a vote for a potential winner means anything, or whether they will stick with Nader, using their vote, it would seem, to express a fundamental dissatisfaction with the current political system.

Charbonneau, David D.

28

Solar Energy Utilisation Potential of three different Swiss Urban Sites  

Microsoft Academic Search

Besides providing a more efficient energy use, a large scale application of solar energy technologies in the urban context will be required in the upcoming decades to achieve a drastic reduction of greenhouse gas emissions in the biosphere. Three different urban sites, representative of three of the largest Swiss cities (Basel, Geneva and Lausanne), were examined in order to assess

M Montavon; J-L Scartezzini; R Compagnon

29

Pushbroom radiometry and its potential using large space antennas  

NASA Technical Reports Server (NTRS)

Electromagnetic radiation is emitted by matter which was heated to a temperature above absolute zero. The amount of blackbody radiation in the microwave frequency region of interest (10 to the 8th power f 10 to the 10th power Hz) emitted by matter can be determined from the Rayleigh-Jeans approximation to Planck's Radiation Law. The amount of electromagnetic radiation from matter which is not a blackbody is a function of the emissivity of the material. The emissivity is a factor less than unity and is a function of several parameters including chemical composition, temperature, frequency, surface characteristics, and viewing angle. A radiometer is an instrument which detects and provides a measure of the electromagnetic radiation being emitted by a material or surface area within the radiometer's antenna beamwidth. Microwave radiometers provide the capability for remote measurements from Earth orbits of geophysical parameters. These measurements will require the use of a microwave imaging radiometer using a large aperture deployable antenna with multiple beams in a pushbroom mode to achieve high spatial resolution and large swath width.

Harrington, R. F.; Keafer, L. S., Jr.

1983-01-01

30

Large Scale Predictions of Potential Post-fire Erosion  

NASA Astrophysics Data System (ADS)

High-severity wildfires are of increasing concern because of their potential for initiating flash floods and surface erosion, degrading water quality, and reducing reservoir capacity. In many areas fire suppression has increased fuel accumulations and hence the potential for high-severity wildfires. Land management agencies are undertaking programs to reduce fuel loadings and the associated risk of high-severity wildfires, but the areas needing treatment greatly exceed the available funding. It is therefore necessary to determine which areas should have a higher priority for such treatments. Similarly, when wildfires do occur there is an immediate need to determine which areas should have the highest priority for post-fire rehabilitation treatments. One criterion for allocating treatments is the potential risk of post-fire erosion, but to be effective this assessment needs to be carried out at a broad scale. This paper presents a procedure and initial results for predicting spatially-explicit, post-fire erosion risks at the hillslope scale for forest and shrub lands across the western U.S. Our approach utilizes existing physical models and datasets in a GIS framework. The model for predicting erosion is GeoWEPP, the Geographical interface for the Water Erosion Prediction Project (WEPP). The primary inputs for GeoWEPP include climate, topography, soils, and land cover/land use. Daily climate inputs were generated with Cligen, which is a stochastic weather generator distributed with WEPP. A 30-m digital elevation model, STATSGO-derived soils data, and vegetation cover were obtained from the U.S. Forest Service's LANDFIRE project. Since recent research has shown that percent ground cover is a dominant control on post-fire erosion rates, we generated a spatially-explicit map of post-fire ground cover by first using historic weather data to determine the 1000-hr fuel moisture values when fuel conditions were at 98-100% ERC (Energy Released Component). These fuel moisture values were fed into FOFEM (First Order Fire Effects Model) to obtain spatially-explicit predictions of percent ground cover, and this provided the additional land cover/land use information needed by GeoWEPP. The predicted erosion rates are comparable to measured values in the Colorado Front Range, but are much too high for the higher rainfall areas along the Pacific Coast. This pattern indicates that precipitation is having a pre-dominant effect on predicted post-fire erosion rates, especially in areas that are projected to burn at low severity. Hence the predicted erosion rates will be most useful in relative terms at the local and possibly regional scale, while comparisons between regions may be of more limited validity.

Miller, M. E.; MacDonald, L. H.

2005-12-01

31

Adaptive differences in the body proportions of large felids.  

PubMed

Body proportions of eight species of large felids were studied and the relationship between their morphology, habitat structure and habitat utilization was analyzed. Both Panthera onca and Neofelis nebulosa are exclusive forest dwellers (found exclusively in high densly structured habitats). These felids have the relatively shortest anterior limbs and lumbar spine. In addition, P. onca has the relatively shortest posterior limbs of the large felids, while the posterior limbs of N. nebulosa are relatively long when compared with those of P. onca which seems to be an adaptation for jumping. All large fields use the anterior limbs to make primary contact with their prey. In addition, the prey taken by the forest fields can exceed their own body weight. On the other hand, the cheetah is found in low structured habitats (savanna), and it has the relatively longest limbs and lumbarspine of the large felids. But the cheetah's prey usually weigh less than its own body weight. The cheetah also employs a 'rapid pursuit phase' in hunting and is capable of overtaking its prey. The lion, however, was found to have the body proportions of a forest felid, yet it also resides in low structured habitats. It is postulated that the utilization of large prey by the lion limits the possibilities for morphological adaptations for speed. To increase hunting efficiency, reproductive success, and territorial defense on the plains, lions form prides. PMID:973541

Gonyea, W J

1976-01-01

32

Adaptive differences in the body proportions of large felids  

Microsoft Academic Search

Body proportions of eight species of large felids were studied and the relationship between their morphology, habitat structure and habitat utilization was analyzed. Both Panthera onca and Neofelis nebulosa are exclusive forest dwellers (found exclusively in high densly structured habitats). These felids have the relatively shortest anterior limbs and lumbar spine. In addition, P. onca has the relatively shortest posterior

William J. Gonyea

1976-01-01

33

Correlation of variations in intraluminal pressure and potential differences in the perfused colen.  

PubMed Central

To investigate the nature of variations in the large intestine potential differences, a continuous perfusion of isotonic saline was carried out in the colon of 14 rats. Intraluminal pressure and potential differences between the lumen and the peritoneal cavity were continuously and simultaneously recorded, while impedance of the system and respiration were also constantly monitored. To obtain a quantitative evaluation of the data, Fast Fouier Transform was performed on the signals and their derivatives which were auto- and cross-correlated. While there was no obvious relation between pressure and potential in the unperfused colon, there was clear visual qualirative evidence that, during steady state conditions of perfusion, an increase in intraluminal pressure was accompanied by a decrease in potential differences, while impedance of the recording system remained unchanged. Computer analysis disclosed four narrow ranges of stable frequencies for both pressure and potential. They were centred around 0-3, 1-75, 10-7, and 75 cycles per minute, the latter being synchronous with respiration. It is concluded that the variations of potential differences recorded during perfusion, a well-know phenomenon, are not electrical artefacts: the fast rhythm is probably induced by respiration, which increases intracolonic pressure and that, in turn, reduces the absolute value of potential differences, which remain negative mucosa versus serosa. The slower rhythms are synchronous for pressure and potential. Mechanisms responsible for the decrease in potential related to the increase in pressure remain unknown.

Postaire, J G; Gerard, J; Devroede, G; Van Houtte, N

1977-01-01

34

Large phase difference of soliton-like mutually-trapped beam pairs in strong nonlocal media  

NASA Astrophysics Data System (ADS)

We discuss the propagation of two orthogonally polarized beams in nonlocal planar waveguides by variational approach as well as a numerical method. The evolution equations for parameters and the critical powers for soliton-like mutually-trapped propagation of the two beams are obtained. Moreover, we analyze the influence of coupling coefficient, initial power, birefringence and the degree of nonlocal on mutually-trapped propagation. In addition, we find that the two beams will have large phase difference since phase shifts of the two beams are different under certain conditions. This theoretical result may have potential applications in the light-control-light technology.

Wang, Qing; Li, Jingzhen

2014-10-01

35

OBTAINING POTENTIAL FIELD SOLUTIONS WITH SPHERICAL HARMONICS AND FINITE DIFFERENCES  

SciTech Connect

Potential magnetic field solutions can be obtained based on the synoptic magnetograms of the Sun. Traditionally, a spherical harmonics decomposition of the magnetogram is used to construct the current- and divergence-free magnetic field solution. This method works reasonably well when the order of spherical harmonics is limited to be small relative to the resolution of the magnetogram, although some artifacts, such as ringing, can arise around sharp features. When the number of spherical harmonics is increased, however, using the raw magnetogram data given on a grid that is uniform in the sine of the latitude coordinate can result in inaccurate and unreliable results, especially in the polar regions close to the Sun. We discuss here two approaches that can mitigate or completely avoid these problems: (1) remeshing the magnetogram onto a grid with uniform resolution in latitude and limiting the highest order of the spherical harmonics to the anti-alias limit; (2) using an iterative finite difference algorithm to solve for the potential field. The naive and the improved numerical solutions are compared for actual magnetograms and the differences are found to be rather dramatic. We made our new Finite Difference Iterative Potential-field Solver (FDIPS) a publicly available code so that other researchers can also use it as an alternative to the spherical harmonics approach.

Toth, Gabor; Van der Holst, Bart; Huang Zhenguang [Center for Space Environment Modeling, University of Michigan, Ann Arbor, MI 48109 (United States)

2011-05-10

36

Comparing different coarse-grained potentials for star polymers.  

PubMed

We compare different coarse-grained single-blob models for star polymers. We find that phenomenological models inspired by the Daoud-Cotton theory reproduce quite poorly the thermodynamics of these systems, even if the potential is assumed to be density dependent, as done in the analysis of experimental results. Using the numerically determined coarse-grained potential, we also determine the minimum value f(c) of the functionality of the star polymer for which a fluid-solid transition occurs. By applying the Hansen-Verlet criterion we find 35 < f(c) ? 40. This result is confirmed by an analysis that uses the modified (reference) hypernetted chain method and is qualitatively consistent with previous work. PMID:23556746

Menichetti, Roberto; Pelissetto, Andrea

2013-03-28

37

Comparing different coarse-grained potentials for star polymers  

NASA Astrophysics Data System (ADS)

We compare different coarse-grained single-blob models for star polymers. We find that phenomenological models inspired by the Daoud-Cotton theory reproduce quite poorly the thermodynamics of these systems, even if the potential is assumed to be density dependent, as done in the analysis of experimental results. Using the numerically determined coarse-grained potential, we also determine the minimum value fc of the functionality of the star polymer for which a fluid-solid transition occurs. By applying the Hansen-Verlet criterion we find 35 < fc <~ 40. This result is confirmed by an analysis that uses the modified (reference) hypernetted chain method and is qualitatively consistent with previous work.

Menichetti, Roberto; Pelissetto, Andrea

2013-03-01

38

Resolving the Difference in Electric Potential within a Charged Macromolecule  

NASA Astrophysics Data System (ADS)

The difference of the electric potential between the middle and end of polystyrene sulfonate (PSS-) chain is discovered experimentally. Using a pH-responsive fluorophore attached to these two locations on the PSS- chain, the local pH value was determined by single molecule fluorescence technique: photon counting histogram (PCH). By the observation of a very high accumulation of proton (2-3 orders of magnitude in concentration) at the vicinity of the PSS- as the result of the electrostatic attraction between the charged chain and protons, the electric potential of the PSS- chain is determined. A higher extent of counterion adsorption is discovered at the middle of the PSS- chain than the chain end. The entropy effect of the counterion adsorption is also discovered - upon the dilution of protons, previously adsorbed counterions are detached from the chain.

Luo, Shuangjiang; Yang, Jingfa; Zhao, Jiang

2013-03-01

39

Basic protocol for transepithelial nasal potential difference measurements.  

PubMed

Transepithelial nasal potential difference (NPD) measurements assess ion conductance in the upper respiratory epithelium. NPD is useful in assisting in the diagnosis of classical and atypical cystic fibrosis (CF) and of cystic fibrosis transmembrane regulator (CFTR)-related disorders, as well as for monitoring the effect of pharmacological agents and gene transfer approaches to correct the abnormalities of ion transport in CF. The article summarizes the objectives and the principle of NPD measurements, describes a hands-on protocol of the procedure and provides quality control measures, practical hints and troubleshooting. PMID:15463949

Schüler, Daniel; Sermet-Gaudelus, Isabelle; Wilschanski, Michael; Ballmann, Manfred; Dechaux, Michèle; Edelman, Aleksander; Hug, Martin; Leal, Teresinha; Lebacq, Jean; Lebecque, Patrick; Lenoir, Gérard; Stanke, Frauke; Wallemacq, Pierre; Tümmler, Burkhard; Knowles, Michael R

2004-08-01

40

Nasal potential difference measurements to assess CFTR ion channel activity.  

PubMed

The Nasal potential difference measurement is used to measure the voltage across the nasal epithelium, which results from transepithelial ion transport and reflects in part CFTR function. The electrophysiologic abnormality in cystic fibrosis was first described 30 years ago and correlates with features of the CF phenotype. NPD measurement is an important in vivo research and diagnostic tool, and is used to assess the efficacy of new treatments such as gene therapy and ion transport modulators. This chapter will elaborate on the electrophysiological principles behind the test, the equipment required, the methods, and the analysis of the data. PMID:21594779

Rowe, Steven M; Clancy, John Paul; Wilschanski, Michael

2011-01-01

41

Injury Differences Between Small and Large Overlap Frontal Crashes  

PubMed Central

Because small overlap impacts have recently emerged as a crash mode posing great injury risk to occupants, a detailed analysis of US crash data was conducted using the NASS/CDS and CIREN databases. Frontal crashes were subcategorized into small overlap impact (SOI) and large overlap impact (LOI) using crash and crush characteristics from the datasets. Injuries to head, spine, chest, hip and pelvis, and lower extremities were parsed and compared between crash types. MAIS 3+ occupants in NASS/CDS and CIREN demonstrated increased incidence of head, chest, spine, and hip/pelvis injuries in SOI compared to LOI. In NASS/CDS, subgaleal hematoma represented 48.6% of SOI head injury codes but 27.6% in LOI. Cervical spine posterior element fractures also represented greater proportions of SOI spine injuries (e.g., facet fractures: 27.8 vs. 14.0%), and proximal femur fractures represented a greater proportion of hip/pelvis injuries (e.g., intertrochanteric fracture: 32.5 vs. 11.8%). Tarsal/metatarsal fractures were a lesser proportion of lower extremity injuries in SOI compared to LOI. Occupant contact points inducing these injuries were observed in CIREN cases in some instances without compartment intrusion. These injuries suggest the substantial role of occupant kinematics in SOI which may induce suboptimal occupant restraint interaction.

Hallman, Jason J.; Yoganandan, Narayan; Pintar, Frank A.; Maiman, Dennis J.

2011-01-01

42

Injury differences between small and large overlap frontal crashes.  

PubMed

Because small overlap impacts have recently emerged as a crash mode posing great injury risk to occupants, a detailed analysis of US crash data was conducted using the NASS/CDS and CIREN databases. Frontal crashes were subcategorized into small overlap impact (SOI) and large overlap impact (LOI) using crash and crush characteristics from the datasets. Injuries to head, spine, chest, hip and pelvis, and lower extremities were parsed and compared between crash types. MAIS 3+ occupants in NASS/CDS and CIREN demonstrated increased incidence of head, chest, spine, and hip/pelvis injuries in SOI compared to LOI. In NASS/CDS, subgaleal hematoma represented 48.6% of SOI head injury codes but 27.6% in LOI. Cervical spine posterior element fractures also represented greater proportions of SOI spine injuries (e.g., facet fractures: 27.8 vs. 14.0%), and proximal femur fractures represented a greater proportion of hip/pelvis injuries (e.g., intertrochanteric fracture: 32.5 vs. 11.8%). Tarsal/metatarsal fractures were a lesser proportion of lower extremity injuries in SOI compared to LOI. Occupant contact points inducing these injuries were observed in CIREN cases in some instances without compartment intrusion. These injuries suggest the substantial role of occupant kinematics in SOI which may induce suboptimal occupant restraint interaction. PMID:22105392

Hallman, Jason J; Yoganandan, Narayan; Pintar, Frank A; Maiman, Dennis J

2011-01-01

43

The radiative forcing potential of different climate geoengineering options  

NASA Astrophysics Data System (ADS)

Climate geoengineering proposals seek to rectify the Earth's current radiative imbalance, either by reducing the absorption of incoming solar (shortwave) radiation, or by removing CO2 from the atmosphere and transferring it to long-lived reservoirs, thus increasing outgoing longwave radiation. A fundamental criterion for evaluating geoengineering options is their climate cooling effectiveness, which we quantify here in terms of radiative forcing potential. We use a simple analytical approach, based on the global energy balance and pulse response functions for the decay of CO2 perturbations. This aids transparency compared to calculations with complex numerical models, but is not intended to be definitive. Already it reveals some significant errors in existing calculations, and it allows us to compare the relative effectiveness of a range of proposals. By 2050, only stratospheric aerosol injections or sunshades in space have the potential to cool the climate back toward its pre-industrial state, but some land carbon cycle geoengineering options are of comparable magnitude to mitigation "wedges". Strong mitigation, i.e. large reductions in CO2 emissions, combined with global-scale air capture and storage, afforestation, and bio-char production, i.e. enhanced CO2 sinks, might be able to bring CO2 back to its pre-industrial level by 2100, thus removing the need for other geoengineering. Alternatively, strong mitigation stabilising CO2 at 500 ppm, combined with geoengineered increases in the albedo of marine stratiform clouds, grasslands, croplands and human settlements might achieve a patchy cancellation of radiative forcing. Ocean fertilisation options are only worthwhile if sustained on a millennial timescale and phosphorus addition probably has greater long-term potential than iron or nitrogen fertilisation. Enhancing ocean upwelling or downwelling have trivial effects on any meaningful timescale. Our approach provides a common framework for the evaluation of climate geoengineering proposals, and our results should help inform the prioritisation of further research into them.

Lenton, T. M.; Vaughan, N. E.

2009-01-01

44

Lessons learned from two very different large radioactive spills  

SciTech Connect

Hard lessons in radioactive spill response, including decontamination and confinement methods, priority setting, survey techniques, and release limit determination were learned (by trial and error) from two spills which occurred recently at the Radiochemical Engineering and Development Center (REDC) at Oak Ridge National Laboratory. The responsibilities of radiological control personnel, decontamination workers, and facility management were often redefined as decontamination progressed. While each spill involved {approximately}1 Ci, their essential characteristics and isotopic distributions were quite different requiring innovative and pragmatic solutions. The first spill was liquid waste with water soluble fission products mixed in an organic solution of actinides. Rain, snowmelt, fog, and darkness foiled initial confinement efforts and contributed to the spread of contamination over several hundred square meters of concrete, asphalt, and floor covering. Contaminated runoff escaped into the environment until effective preventative measures were developed and put in place. The second spill happened when {sup 224}Cm and {sup 241}Am were accidentally siphoned from an in-cell product holding tank onto the floor of the Limited Access Area at the REDC. Several decontamination techniques were tried before an effective one was developed.

Waggoner, J.K. [Oak Ridge National Laboratory, TN (United States)

1996-06-01

45

Estimating Large-Customer Demand Response Market Potential:Integrating Price and Customer Behavior  

SciTech Connect

ABSTRACT=Demand response (DR) is increasingly recognized asan essential ingredient to well-functioning electricity markets. DRmarket potential studies can answer questions about the amount of DRavailable in a given area, from which market segments. Several recent DRmarket potential studies have been conducted, most adapting techniquesused to estimate energy-efficiency (EE) potential. In this scoping study,we: reviewed and categorized seven recent DR market potential studies;recommended a methodology for estimating DR market potential for large,non-residential utility customers that uses price elasticities to accountfor behavior and prices; compiled participation rates and elasticityvalues from six DR options offered to large customers in recent years,and demonstrated our recommended methodology with large customer marketpotential scenarios at an illustrative Northeastern utility. We recommendan elasticity approach for large-customer DR options that rely oncusto!

Goldman, Charles; Hopper, Nicole; Bharvirkar, Ranjit; Neenan,Bernie; Cappers, Peter

2007-06-01

46

Pre-anthesis ovary development determines genotypic differences in potential kernel weight in sorghum  

PubMed Central

Kernel weight is an important factor determining grain yield and nutritional quality in sorghum, yet the developmental processes underlying the genotypic differences in potential kernel weight remain unclear. The aim of this study was to determine the stage in development at which genetic effects on potential kernel weight were realized, and to investigate the developmental mechanisms by which potential kernel weight is controlled in sorghum. Kernel development was studied in two field experiments with five genotypes known to differ in kernel weight at maturity. Pre-fertilization floret and ovary development was examined and post-fertilization kernel-filling characteristics were analysed. Large kernels had a higher rate of kernel filling and contained more endosperm cells and starch granules than normal-sized kernels. Genotypic differences in kernel development appeared before stamen primordia initiation in the developing florets, with sessile spikelets of large-seeded genotypes having larger floret apical meristems than normal-seeded genotypes. At anthesis, the ovaries for large-sized kernels were larger in volume, with more cells per layer and more vascular bundles in the ovary wall. Across experiments and genotypes, there was a significant positive correlation between kernel dry weight at maturity and ovary volume at anthesis. Genotypic effects on meristem size, ovary volume, and kernel weight were all consistent with additive genetic control, suggesting that they were causally related. The pre-fertilization genetic control of kernel weight probably operated through the developing pericarp, which is derived from the ovary wall and potentially constrains kernel expansion.

Yang, Zongjian; van Oosterom, Erik J.; Jordan, David R.; Hammer, Graeme L.

2009-01-01

47

Racial Differences in Blood Pressure Control: Potential Explanatory Factors  

PubMed Central

Summary Objective The objective of the study was to identify potential explanatory factors for racial differences in blood pressure (BP) control. Design The design of the study was a cross-sectional study Patients/Participants The study included 608 patients with hypertension who were either African American (50%) or white (50%) and who received primary care in Durham, NC. Measurements and Main Results Baseline data were obtained from the Take Control of Your Blood pressure study and included clinical, demographic, and psychosocial variables potentially related to clinic BP measures. African Americans were more likely than whites to have inadequate baseline clinic BP control as defined as greater than or equal to 140/90 mmHg (49% versus 34%; unadjusted odds ratio [OR] 1.8; 95% confidence interval [CI] 1.3–2.5). Among factors that may explain this disparity, being older, reporting hypertension medication nonadherence, reporting a hypertension diagnosis for more than 5 years, reporting high levels of stress, being worried about hypertension, and reporting an increased number of medication side effects were related to inadequate BP control. In adjusted analyses, African Americans continue to have poor BP control relative to whites; the magnitude of the association was reduced (OR?=?1.5; 95% CI 1.0–2.1). Medication nonadherence, worries about hypertension, and older age (>70) continued to be related to poor BP control. Conclusions In this sample of hypertensive patients, there were a number of factors associated with poor BP control that partially explained the observed racial disparity in hypertension control including age, medication nonadherence, and worry about BP. Medication nonadherence is of particular interest because it is a potentially modifiable factor that might be used to reduce the racial disparity in BP control.

Powers, Benjamin; Grubber, Janet M.; Thorpe, Carolyn T.; Olsen, Maren K.; Orr, Melinda; Oddone, Eugene Z.

2008-01-01

48

Ocular Vestibular Evoked Myogenic Potential Using Different Test Stimuli  

PubMed Central

Aim. Ocular Evoked Myogenic Potential (oVEMP) are short latency potentials evoked by higher acoustic stimulation. In this study, we aimed at comparing the click, 500?Hz mixed modulated, and 500?Hz short duration tone burst stimuli using oVEMP. Material. Click, 500?Hz mixed modulated and 500?Hz short duration tone burst stimuli were used for the study. Method. Conventional sampling and conveneint study design were used. Sixty healthy subjects underwent contralateral oVEMP testing maintaining 30 degrees upward gaze. Single channel electrode montage was applied to record oVEMP response. Results. On statistical analysis the three stimuli evoked equal response rates (100%), and when latency of n1 and p1 and peak-peak amplitude were compared, the click evoked showed significantly early latency and lower peak-peak amplitude than the 500?Hz stimuli. Five hundred Hz stimuli did not show significant difference in latency and peak-peak amplitude of n1-p1. Discussion. Thus, 500?Hz stimuli can evoke better latency and peak-peak amplitude. oVEMP has good clinical significance in diagnosing subjects with vestibular dysfunction. To add to the sensitivity of the oVEMP test, 500?Hz stimuli may also be used as it can evoke better oVEMP responses in clinical population with good morphology.

Deepak, Dessai Teja; Bhat, Jayashree S.; Kumar, Kaushlendra

2013-01-01

49

Racial Differences in Blood Pressure Control: Potential Explanatory Factors  

Microsoft Academic Search

Summary\\u000a Objective  The objective of the study was to identify potential explanatory factors for racial differences in blood pressure (BP) control.\\u000a \\u000a \\u000a \\u000a Design  The design of the study was a cross-sectional study\\u000a \\u000a \\u000a \\u000a Patients\\/Participants  The study included 608 patients with hypertension who were either African American (50%) or white (50%) and who received primary\\u000a care in Durham, NC.\\u000a \\u000a \\u000a \\u000a Measurements and Main Results  Baseline data were obtained

Hayden B. Bosworth; Benjamin Powers; Janet M. Grubber; Carolyn T. Thorpe; Maren K. Olsen; Melinda Orr; Eugene Z. Oddone

2008-01-01

50

Assessing the differences in sensitivities of runoff to changes in climatic conditions across a large basin  

NASA Astrophysics Data System (ADS)

SummaryLong term average runoff depends largely on climatic conditions and is expected to change as climate change progresses, but to what degree and in which locations is uncertain. An analytical framework for assessing the sensitivity of runoff to changes in average precipitation and potential evaporation has recently been developed. This framework is based on Budyko's curve. It makes no assumptions about future climatic conditions and is simple to implement. Here we apply it spatially to the Murray Darling Basin (MDB) in Australia, for average 1981-2006 conditions, to gauge the differences in runoff sensitivity across different yield zones. The framework contains a catchment-specific parameter which is difficult to predict, and estimates of its value are explored and assessed. Results emphasise the importance of the spatial variation in runoff sensitivity. Due to the MDB's aridity, basin-average runoff is very low (around 28 mm y -1) and runoff is generally insensitive to changes in average precipitation and potential evaporation. Specifically, basin-wide runoff is expected to increase by 1 mm y -1 for a 10 mm y -1 increase in basin-average precipitation, and to remain unchanged for the same increase in potential evaporation. However, approximately 66% of basin flow originates from 12% of the basin's land area and in these few high yield catchments runoff is most sensitive to changes in climatic conditions. In the highest yield zone, runoff is expected to increase by 7 mm y -1 given a 10 mm y -1 increase in precipitation, and to decrease by around 4 mm y -1 for the same increase in potential evaporation. When applied spatially, this runoff sensitivity framework has the potential to help water managers and policy makers to target planning activities that seek to mitigate potential effects of a changing climate on water resources.

Donohue, Randall J.; Roderick, Michael L.; McVicar, Tim R.

2011-09-01

51

Potential theory for shock reflection by a large-angle wedge  

PubMed Central

When a plane shock hits a wedge head on, it experiences a reflection, and then a self-similar reflected shock moves outward as the original shock moves forward in time. Experimental, computational, and asymptotic analysis has shown that various patterns of reflected shocks may occur, including regular and Mach reflection. However, most fundamental issues for shock reflection phenomena have not been understood, such as the transition among the different patterns of shock reflection; therefore, it is essential to establish a global existence and stability theory for shock reflection. On the other hand, there has been no rigorous mathematical result on the global existence and stability of solutions to shock reflection, especially for potential flow, which has widely been used in aerodynamics. The theoretical problems involve several challenging difficulties in the analysis of nonlinear partial differential equations including elliptic-hyperbolic mixed type, free-boundary problems, and corner singularity, especially when an elliptic degenerate curve meets a free boundary. Here we develop a potential theory to overcome these difficulties and to establish the global existence and stability of solutions to shock reflection by a large-angle wedge for potential flow. The techniques and ideas developed will be useful to other nonlinear problems involving similar difficulties.

Chen, Gui-Qiang; Feldman, Mikhail

2005-01-01

52

The potential of large studies for building genetic risk prediction models  

Cancer.gov

Posted on March 04, 2013 NCI scientists have developed a new paradigm to assess hereditary risk prediction in common diseases, such as prostate cancer.  Researchers assessed the potential of using very large, genome-wide association studies (GWAS) to

53

Distribution of membrane anionic sites on B16 melanoma variants with differing lung colonising potential  

Microsoft Academic Search

The interaction of metastatic cells with their environment is mediated to a large extent by the cell surface1-5. Although several biochemical differences beteen tumour cells with low or high metastatic potentials have been reported6-10, the specific surface characteristics associated with metastasis have not yet been identified. One distinctive feature of murine B16 melanoma variants with low (B16-F1, B16-F10Lr) or high

A. Raz; C. Bucana; W. McLellan; I. J. Fidler

1980-01-01

54

Evaluation of Curvularia intermedia ( Cochliobolus intermedius) as a potential microbial herbicide for large crabgrass ( Digitaria sanguinalis)  

Microsoft Academic Search

Curvularia intermedia, anamorph of the fungus Cochliobolus intermedius, was isolated from diseased crabgrass (Digitaria sp.) plants and evaluated in greenhouse studies for its potential as a microbial herbicide for control of large crabgrass (Digitaria sanguinalis). The objectives were to evaluate the host range of the fungus and to determine mortality and dry-weight reductions of large crabgrass as influenced by concentrations

A Michael Tilley; H Lynn Walker

2002-01-01

55

Effect of large ion angular momentum spread and high current on inertial electrostatic confinement potential structures  

Microsoft Academic Search

Prior inertial electrostatic confinement (IEC) studies have assumed that very low angular momentum (zero in the ideal case) is necessary to achieve a potential well structure capable of trapping energetic ions in the center of a spherical device. However, the present study shows that high-current ion beams having large-angular-momentum spread can also form deep potential well traps

Ivon V. Tzonev; John M. DeMora; George H. Miley

1995-01-01

56

Study of cascades damage in Ni by MD with different interatomic potentials  

NASA Astrophysics Data System (ADS)

Molecular dynamics (MD) simulations, performed with embedded atom potentials, are used to understand the formation of defects following displacement cascades in Ni. Different empirical potentials, presenting large differences in stacking fault energy (SFE), are used. Simulations were conducted with primary knock-on (PKA) atom energies of 5-40 keV at a temperature of 10 K. Defects include, depending on the potential, individual point defects (vacancies and interstitials), dislocation loops and stacking fault tetrahedra (SFT). The results are related to TEM observations, and the mismatch between these two pictures is discussed. It appears that in a collision cascade, the formation of an SFT does not depend only on the SFE but also on other parameters such as the mobility of vacancies and self-interstitials, or the presence of replacement collision sequences. Based on these calculations we suggest that the formation of clusters of vacancies is a prerequisite to the formation of SFTs.

Yao, Z.; Caturla, M. J.; Schäublin, R.

2007-08-01

57

Chiral symmetry restoration at large chemical potential in strongly coupled SU(N) gauge theories  

SciTech Connect

We show that at sufficiently large chemical potential SU(N) lattice gauge theories in the strong coupling limit with staggered fermions are in a chirally symmetric phase. The proof employs a polymer cluster expansion which exploits the anisotropy between timelike and spacelike directions in the presence of a quark chemical potential ?. The expansion is shown to converge in the infinite volume limit at any temperature for sufficiently large ?. All expectations of chirally non-invariant local fermion operators vanish identically, or, equivalently, their correlations cluster exponentially, within the expansion. The expansion itself may serve as a computational tool at large ? and strong coupling.

Tomboulis, E. T. [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095-1547 (United States)] [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095-1547 (United States)

2013-12-15

58

THE ORIGIN OF THE POTENTIAL DIFFERENCES RESPONSIBLE FOR ANOMALOUS OSMOSIS  

PubMed Central

1. Collodion bags coated with gelatin on the inside were filled with a M/256 solution of neutral salt (e.g., NaCl, CaCl2, CeCl3, or Na2SO4) made up in various concentrations of HNO3 (varying from N/50,000 to N/100). Each collodion bag was put into an HNO3 solution of the same concentration as that inside the bag but containing no salt. In this case water diffuses from the outside solution (containing no salt) into the inside solution (containing the salt) with a relative initial velocity which can be expressed by the following rules: (a) Water diffuses into the salt solution as if the particles of water were negatively charged and as if they were attracted by the cation and repelled by the anion of the salt with a force increasing with the valency of the ion. (b) The initial rate of the diffusion of water is a minimum at the hydrogen ion concentration of about N/50,000 HCl (pH 4.7, which is the point at which gelatin is not ionized), rises with increasing hydrogen ion concentration until it reaches a maximum and then diminishes again with a further rise in the initial hydrogen ion concentration. 2. The potential differences between the salt solution and the outside solution (originally free from salt) were measured after the diffusion had been going on for 1 hour; and when these values were plotted as ordinates over the original pH as abscissae, the curves obtained were found to be similar to the osmotic rate curves. This confirms the view expressed by Girard) Bernstein, Bartell, and Freundlich that these cases of anomalous osmosis are in reality cases of electrical endosmose where the driving force is a P.D. between the opposite sides of the membrane. 3. The question arose as to the origin of these P. D. and it was found that the P.D. has apparently a double origin. Certain features of the P.D. curve, such as the rise and fall with varying pH, seem to be the consequence of a Donnan equilibrium which leads to some of the free HNO3 being forced from the solution containing salt into the outside solution containing no (or less) salt. This difference of the concentration of HNO3, on the opposite sides of the membrane leads to a P.D. which in conformity with Nernst's theory of concentration cells should be equal to 58 x (pH inside minus pH outside) millivolts at 18°C. The curves of the values of (pH inside minus pH outside) when plotted as ordinates over the original pH as abscissae lead to curves resembling those for the P. D. in regard to location of minimum and maximum. 4. A second source of the P.D. seems to be diffusion potentials, which exist even if no membranes are present and which seem to be responsible for the fact that the rate of diffusion of negatively charged water into the salt solution increases with the valency of the cation and diminishes with the valency of the anion of the salt. 5. The experiments suggest the possibility that the establishment of a Donnan equilibrium between membrane and solution is one of the factors determining the Helmholtzian electrical double layer, at least in the conditions of our experiments.

Loeb, Jacques

1921-01-01

59

Gender differences, polypharmacy, and potential pharmacological interactions in the elderly  

PubMed Central

OBJECTIVE: This study aims to analyze pharmacological interactions among drugs taken by elderly patients and their age and gender differences in a population from Porto Alegre, Brazil. METHODS: We retrospectively analyzed the database provided by the Institute of Geriatric and Gerontology, Porto Alegre, Brazil. The database was composed of 438 elderly and includes information about the patients' disease, therapy regimens, utilized drugs. All drugs reported by the elderly patients were classified using the Anatomical Therapeutic and Chemical Classification System. The drug-drug interactions and their severity were assessed using the Micromedex® Healthcare Series. RESULTS: Of the 438 elderly patients in the data base, 376 (85.8%) used pharmacotherapy, 274 were female, and 90.4% of females used drugs. The average number of drugs used by each individual younger than 80 years was 3.2±2.6. Women younger than 80 years old used more drugs than men in the same age group whereas men older than 80 years increased their use of drugs in relation to other age groups. Therefore, 32.6% of men and 49.2% of women described at least one interaction, and 8.1% of men and 10.6% of women described four or more potential drug-drug interactions. Two-thirds of drug-drug interactions were moderate in both genders, and most of them involved angiotensin-converting enzyme inhibitor, non-steroidal anti-inflammatory, loop and thiazide diuretics, and ?-blockers. CONCLUSION: Elderly patients should be closely monitored, based on drug class, gender, age group and nutritional status.

Venturini, Carina Duarte; Engroff, Paula; Ely, Luisa Scheer; de Araujo Zago, Luisa Faria; Schroeter, Guilherme; Gomes, Irenio; De Carli, Geraldo Attilio; Morrone, Fernanda Bueno

2011-01-01

60

Characterizing the existing and potential structural space of proteins by large-scale multiple loop permutations  

PubMed Central

Worldwide structural genomics projects are increasing structure coverage of sequence space but have not significantly expanded the protein structure space itself (i.e. number of unique structural folds) since 2007. Discovering new structural folds experimentally by directed evolution and random recombination of secondary-structure blocks is also proved rarely successful. Meanwhile, previous computational efforts for large-scale mapping of protein structure space are limited to simple model proteins and led to an inconclusive answer on the completeness of the existing, observed protein structure space. Here, we build novel protein structures by extending naturally occurring circular (single-loop) permutation to multiple-loop permutations (MLP). These structures are clustered by structural similarity measure called TM-Score. The computational technique allows us to produce different structural clusters on the same naturally occurring, packed, stable core but with alternatively connected secondary-structure segments. A large-scale MLP of 2936 SCOP domains reproduces those existing structural clusters (63%) mostly as hubs for many non-redundant sequences and illustrates newly discovered novel clusters as islands adopted by a few sequences only. Results further show that there exist a significant number of novel, potentially stable clusters for medium or large-size single-domain proteins, in particular (>100 amino-acid residues) that are either not yet adopted by nature or adopted only by a few sequences. This study suggests that MLP provides a simple yet highly effective tool for engineering and design of novel protein structures (including naturally knotted proteins). The implication of recovering CASP new-fold targets by MLP on template-based structure prediction is also discussed. Our MLP structures are available for download at the publication page of the website http://sparks.informatics.iupui.edu.

Dai, Liang; Zhou, Yaoqi

2011-01-01

61

Assessment of economically optimal water management and geospatial potential for large-scale water storage  

NASA Astrophysics Data System (ADS)

Assessment of economically optimal water management and geospatial potential for large-scale water storage Weerasinghe, Harshi; Schneider, Uwe A Water is an essential but limited and vulnerable resource for all socio-economic development and for maintaining healthy ecosystems. Water scarcity accelerated due to population expansion, improved living standards, and rapid growth in economic activities, has profound environmental and social implications. These include severe environmental degradation, declining groundwater levels, and increasing problems of water conflicts. Water scarcity is predicted to be one of the key factors limiting development in the 21st century. Climate scientists have projected spatial and temporal changes in precipitation and changes in the probability of intense floods and droughts in the future. As scarcity of accessible and usable water increases, demand for efficient water management and adaptation strategies increases as well. Addressing water scarcity requires an intersectoral and multidisciplinary approach in managing water resources. This would in return safeguard the social welfare and the economical benefit to be at their optimal balance without compromising the sustainability of ecosystems. This paper presents a geographically explicit method to assess the potential for water storage with reservoirs and a dynamic model that identifies the dimensions and material requirements under an economically optimal water management plan. The methodology is applied to the Elbe and Nile river basins. Input data for geospatial analysis at watershed level are taken from global data repositories and include data on elevation, rainfall, soil texture, soil depth, drainage, land use and land cover; which are then downscaled to 1km spatial resolution. Runoff potential for different combinations of land use and hydraulic soil groups and for mean annual precipitation levels are derived by the SCS-CN method. Using the overlay and decision tree algorithms in GIS, potential water storage sites are identified for constructing regional reservoirs. Subsequently, sites are prioritized based on runoff generation potential (m3 per unit area), and geographical suitability for constructing storage structures. The results from the spatial analysis are used as input for the optimization model. Allocation of resources and appropriate dimension for dams and associated structures are identified using the optimization model. The model evaluates the capability of alternative reservoirs for cost-efficient water management. The Geographic Information System is used to store, analyze, and integrate spatially explicit and non-spatial attribute information whereas the algebraic modeling platform is used to develop the dynamic optimization model. The results of this methodology are validated over space against satellite remote sensing data and existing data on reservoir capacities and runoff. The method is suitable for application of on-farm water storage structures, water distribution networks, and moisture conservation structures in a global context.

Weerasinghe, Harshi; Schneider, Uwe A.

2010-05-01

62

A lattice Boltzmann method for incompressible two-phase flows with large density differences  

Microsoft Academic Search

A lattice Boltzmann method for two-phase immiscible fluids with large density differences is proposed. The difficulty in the treatment of large density difference is resolved by using the projection method. The method can be applied to simulate two-phase fluid flows with the density ratio up to 1000. To show the validity of the method, we apply the method to the

T. Inamuro; T. Ogata; S. Tajima; N. Konishi

2004-01-01

63

Differences in the glucuronidation of resveratrol and pterostilbene: altered enzyme specificity and potential gender differences.  

PubMed

  Resveratrol, a natural polyphenol found in grapes, berries and other plants, has been proposed as an ideal chemopreventative agent due to its plethora of health promoting activities. However, despite its lofty promise as a cancer prevention agent its success in human clinical trials has been limited due to its poor bioavailability. Thus, interest in other natural polyphenols is intensifying including the naturally occurring dimethylated analog of resveratrol, pterostilbene. The UDP-glucuronosyltransferase (UGT) family of enzymes plays a vital role in the metabolism of both resveratrol and pterostilbene. The current study sought to elucidate the UGT family members responsible for the metabolism of pterostilbene and to examine gender differences in the glucuronidation of resveratrol and pterostilbene. We demonstrate that UGT1A1 and UGT1A3 are mainly responsible for pterostilbene glucuronidation although UGT1A8, UGT1A9 and UGT1A10 also had detectable activity. Intriguingly, UGT1A1 exhibits the highest activity against both resveratrol and pterostilbene despite altered hydroxyl group specificity. Using pooled human liver microsomes, enzyme kinetics were determined for pterostilbene and resveratrol glucuronides. In all cases females were more efficient than males, indicating potential gender differences in stilbene metabolism. Importantly, the glucuronidation of pterostilbene is much less efficient than that of resveratrol, indicating that pterostilbene will have dramatically decreased metabolism in humans. PMID:23965644

Dellinger, Ryan W; Garcia, Angela M Gomez; Meyskens, Frank L

2014-04-25

64

Portable music player users: cultural differences and potential dangers.  

PubMed

Many studies have examined the use of portable music players portable listening devices (PLDs) from various ethnic groups. Some findings suggest that there may be differences among ethnic groups that lead to louder or longer listening when using PLD devices. For example, some studies found that Hispanic PLD users listen at higher volume levels while other studies found that African American PLD users listen at higher volume levels. No investigator has explained the reasons for differences among ethnic groups in listening intensity. This paper will address the possible reasons for these differences and offer guidelines for the prevention of noise-induced hearing loss. PMID:23955125

Levey, Sandra; Fligor, Brian J; Cutler, Cecelia; Harushimana, Immaculee

2013-01-01

65

PERSPECTIVES ON LARGE-SCALE NATURAL RESOURCES SURVEYS WHEN CAUSE-EFFECT IS A POTENTIAL ISSUE  

EPA Science Inventory

Our objective is to present a perspective on large-scale natural resource monitoring when cause-effect is a potential issue. We believe that the approach of designing a survey to meet traditional commodity production and resource state descriptive objectives is too restrictive an...

66

Identifying potential environmental impacts of large-scale deployment of dedicated bioenergy crops in the UK  

Microsoft Academic Search

Abstract There is momentum, globally, to increase the use of plant biomass for the production of heat, power and liquid transport fuels. This review assesses the evidence base for potential impacts of large-scale bioenergy crop deployment principally within the UK context, but with wider implications for Europe, the USA and elsewhere. We focus on second generation, dedicated lignocellulosic crops, but

Rebecca L. Rowe; Gail Taylor

2007-01-01

67

NYU researchers identify new potential therapeutic target for diffuse large B-cell lymphoma:  

Cancer.gov

Researchers from the NYU Cancer Institute, an NCI-designated cancer center at NYU Langone Medical Center, have discovered a new potential therapeutic target for Diffuse Large B-Cell Lymphoma (DLBCL), the most aggressive and common type of lymphoma in adults. The new study, published in the November 23 issue of Nature, reveals the underlying molecular mechanism contributing to the development of lymphomagenesis.

68

Racial Differences in Blood Pressure Control: Potential Explanatory Factors  

Microsoft Academic Search

PurposePoor blood pressure control remains a common problem that contributes to significant cardiovascular morbidity and mortality, particularly among African Americans. We explored antihypertensive medication adherence and other factors that may explain racial differences in blood pressure control.

Hayden B. Bosworth; Tara Dudley; Maren K. Olsen; Corrine I. Voils; Benjamin Powers; Mary K. Goldstein; Eugene Z. Oddone

2006-01-01

69

Contribution potential of glaciers to water availability in different climate regimes  

PubMed Central

Although reliable figures are often missing, considerable detrimental changes due to shrinking glaciers are universally expected for water availability in river systems under the influence of ongoing global climate change. We estimate the contribution potential of seasonally delayed glacier melt water to total water availability in large river systems. We find that the seasonally delayed glacier contribution is largest where rivers enter seasonally arid regions and negligible in the lowlands of river basins governed by monsoon climates. By comparing monthly glacier melt contributions with population densities in different altitude bands within each river basin, we demonstrate that strong human dependence on glacier melt is not collocated with highest population densities in most basins.

Kaser, Georg; Grosshauser, Martin; Marzeion, Ben

2010-01-01

70

Immobilization of potentially toxic metals using different soil amendments.  

PubMed

The in situ stabilization of potentially toxic metals (PTMs), using various easily available amendments, is a cost-effective remediation method for contaminated soils. In the present study, we investigated the effectiveness of apatite and a commercial mixture of dolomite, diatomite, smectite basaltic tuff, bentonite, alginite and zeolite (Slovakite) on Pb, Zn, Cu and Cd stabilization by means of decreasing their bioavailability in contaminated soil from an old lead and zinc smelter site in Arnoldstein, Austria. We also investigated the impact of 5% (w/w) apatite and Slovakite applications on soil functionality and quality, as assessed by glucose-induced soil respiration, dehydrogenase, acid and alkaline phosphatase and ?-glucosidase activity. Both amendments resulted in increased soil pH and decreased PTM potential bioavailability assessed by diethylenetriamine pentaacetic acid extraction and by sequential extractions in the water-soluble and exchangeable fractions. The efficiency of stabilization was reflected in the soil respiration rate and in enzymatic activity. The ?-glucosidase activity assay was the most responsive of them. PMID:21767865

Tica, D; Udovic, M; Lestan, D

2011-10-01

71

Whitefly control potential of Eretmocerus parasitoids with different reproductive modes  

Microsoft Academic Search

Whiteflies (Homoptera; Aleyrodidae) are amongst the key pests of vegetable, ornamental, and agronomic crops throughout the world. Because of failing and expensive chemical control, much research has been directed at developing biological control by searching for efficient natural enemies of whiteflies. Among different categories of natural enemies, parasitoids have been efficient control agents and cost effective. The aim of the

M. J. Ardeh

2005-01-01

72

Vermicomposting potential of Perionyx sansibaricus (Perrier) in different waste materials  

Microsoft Academic Search

The decomposition efficiency of Perionyx sansibaricus (Perrier) for vermicomposting was evaluated by using a variety of wastes such as agriculture waste, farm yard manure and urban solid waste. Vermicomposting resulted in significant increase in total N (80.8–142.3%), phosphorous (33.1–114.6%) and potassium (26.3–125.2%), whereas decrease in organic C (14.0–37.0%) as well as C:N ratio (52.4–69.8%) in different experimental beddings. P. sansibaricus

Surendra Suthar

2007-01-01

73

Evaluating Potential for Large Releases from CO2 StorageReservoirs: Analogs, Scenarios, and Modeling Needs  

SciTech Connect

While the purpose of geologic storage of CO{sub 2} in deep saline formations is to trap greenhouse gases underground, the potential exists for CO{sub 2} to escape from the target reservoir, migrate upward along permeable pathways, and discharge at the land surface. Such discharge is not necessarily a serious concern, as CO{sub 2} is a naturally abundant and relatively benign gas in low concentrations. However, there is a potential risk to health, safety and environment (HSE) in the event that large localized fluxes of CO{sub 2} were to occur at the land surface, especially where CO{sub 2} could accumulate. In this paper, we develop possible scenarios for large CO{sub 2} fluxes based on the analysis of natural analogues, where large releases of gas have been observed. We are particularly interested in scenarios which could generate sudden, possibly self-enhancing, or even eruptive release events. The probability for such events may be low, but the circumstances under which they might occur and potential consequences need to be evaluated in order to design appropriate site selection and risk management strategies. Numerical modeling of hypothetical test cases is needed to determine critical conditions for such events, to evaluate whether such conditions may be possible at designated storage sites, and, if applicable, to evaluate the potential HSE impacts of such events and design appropriate mitigation strategies.

Birkholzer, Jens; Pruess, Karsten; Lewicki, Jennifer; Tsang,Chin-Fu; Karimjee, Anhar

2005-09-19

74

Altered ion channel conductance and ionic selectivity induced by large imposed membrane potential pulse.  

PubMed Central

The effects of large magnitude transmembrane potential pulses on voltage-gated Na and K channel behavior in frog skeletal muscle membrane were studied using a modified double vaseline-gap voltage clamp. The effects of electroconformational damage to ionic channels were separated from damage to lipid bilayer (electroporation). A 4 ms transmembrane potential pulse of -600 mV resulted in a reduction of both Na and K channel conductivities. The supraphysiologic pulses also reduced ionic selectivity of the K channels against Na+ ions, resulting in a depolarization of the membrane resting potential. However, TTX and TEA binding effects were unaltered. The kinetics of spontaneous reversal of the electroconformational damage of channel proteins was found to be dependent on the magnitude of imposed membrane potential pulse. These results suggest that muscle and nerve dysfunction after electrical shock may be in part caused by electroconformational damage to voltage-gated ion channels.

Chen, W; Lee, R C

1994-01-01

75

Tsunamigenic potential of different tsunamigenic regions in the Pacific  

NASA Astrophysics Data System (ADS)

The historical tsunami catalog collected within the HTDB/PAC (Historical Tsunami Database for the Pacific) project contains the most complete parametric tsunami data covering the Pacific. The collected data gives us a possibility to study the variability of the tsunami potential of submarine earthquakes over the main tsunamigenic areas in the Pacific. Depending on their intensity (on the Soloviev-Imamura scale) all the tsunamigenic events were divided into the three categories: damageable (I>1.5, Hav>3 m), perceptible (-0.5 <= I <= 1.5, 0.5 <= Hav <= 3m) and observable (I < -0.5, Hav < 0.5m), where Hav is an average run-up height at the nearest coast. For each region, the tsunami efficiency (TE) is calculated as a ratio between the number of tsunamis of tectonic, landslide and unknown origin and the total number of the coastal and the submarine earthquakes with magnitude Ms = 7.0 and depth h < 100 km. In the Pacific, the tsunami efficiency, calculated in the above manner, varies from 84% for the South America region to 36% for the New Zealand - Tonga region. The comparison of the variation of the TE ratio with the position of the main sedimentation zones in the Pacific (Lisitsyn, 1974) shows that the regions located within the equatorial humid zone (New Guinea - Solomon, Indonesia, Philippines) have the increased number of tsunamigenic events compared to the regions located in other zones. The circum-continental zonation in the sedimentation rate resulted in the highest TE ratio for the South America region where the tsunamigenic sources are located closest to land. The higher sedimentation rate results in a higher potential for submarine slumping that considerably increases the efficiency of the tsunami generation mechanism. The earthquakes in the marginal seas (the Japan Sea, the Okhotsk Sea, the Bering Sea) have a higher tsunami efficiency as compared to the earthquakes in the Pacific ocean. For Hawaii, the TE ratio exceeds 100%, which shows that some events were generated by the earthquakes with magnitudes less than 7 or even had a non-seismic origin.

Gusiakov, V. K.

2003-04-01

76

Large herbivores maintain termite-caused differences in herbaceous species diversity patterns.  

PubMed

Termites and large herbivores affect African savanna plant communities. Both functional groups are also important for nutrient redistribution across the landscape. We conducted an experiment to study how termites and large herbivores, alone and in combination, affect herbaceous species diversity patterns in an African savanna. Herbaceous vegetation on large vegetated Macrotermes mounds (with and without large herbivores) and on adjacent savanna areas (with and without large herbivores) was monitored over three years in Lake Mburo National Park, Uganda. We found substantial differences in species richness, alpha diversity, evenness, and stability between termite mound herbaceous vegetation and adjacent savanna vegetation. Within months of fencing, levels of species richness, evenness, and stability were no longer significantly different between savanna and mounds. However, fencing reduced the cumulative number of species, particularly for forbs, of which 48% of the species were lost. Fencing increased the beta diversity (dissimilarity among plots) on the resource-poor (in terms of both nutrients and soil moisture) savanna areas, while it did not significantly affect beta diversity on the resource-rich termite mounds. While termites cause substantial heterogeneity in savanna vegetation, large herbivores further amplify these differences by reducing beta diversity on the savanna areas. Large herbivores are, however, responsible for the maintenance of a large number of forbs at the landscape level. These findings suggest that the mechanisms underlying the effects of termites and large herbivores on savanna plant communities scale up to shape community structure and dynamics at a landscape level. PMID:23094381

Okullo, Paul; Moe, Stein R

2012-09-01

77

Large 0/12 GMT Differences of US Vaisala RS80 Observations.  

National Technical Information Service (NTIS)

Large differences between observations taken at 0 and 12 GMT have been released during routine monitoring of observations at the Data Assimilation Office (DAO) at NASA's Goddard Space Flight Center (GSFC). As a result, an investigation has been conducted ...

C. R. Redder

2003-01-01

78

Large 0/12 GMT Differences of US Vaisala RS80 Observations  

NASA Technical Reports Server (NTRS)

Large differences been observations taken at 0 and 12 GMT have been revealed during routine monitoring of observations at the Data Assimilation Office (DAO) at NASA's Goddard Space Flight Center (GSFC). As a result, an investigation has been conducted to confirm the large differences and isolate its source. The data clearly shows that 0/12 GMT differences are largely artificial especially over the central US and that the differences largely originate in the post processing software at the observing stations. In particular, the release time of the rawinsonde balloon may be misspecified to be the synoptic time which would lead to the miscalculation of the bias correction that accounts for solar radiation effects on the thermistor.

Atlas, Robert (Technical Monitor)

2002-01-01

79

Biophysical characterization of bladder cancer cells with different metastatic potential.  

PubMed

Specific membrane capacitance (SMC) and Young's modulus are two important parameters characterizing the biophysical properties of a cell. In this work, the SMC and Young's modulus of two cell lines, RT4 and T24, corresponding to well differentiated (low grade) and poorly differentiated (high grade) urothelial cell carcinoma (UCC), respectively, were quantified using microfluidic and AFM measurements. Quantitative differences in SMC and Young's modulus values of the high-grade and low-grade UCC cells are, for the first time, reported. PMID:23793959

Liu, Haijiao; Tan, Qingyuan; Geddie, William R; Jewett, Michael A S; Phillips, Nigel; Ke, Danbing; Simmons, Craig A; Sun, Yu

2014-03-01

80

Improving High School Students' Understanding of Potential Difference in Simple Electric Circuits  

ERIC Educational Resources Information Center

This paper reports two studies into the understanding of the concept of potential difference in the current-potential difference-resistance context among 8th-12th graders (Study 1), and the efficiency of a learning device derived from Social Judgment Theory (Study 2). These two studies showed that: (a) when asked to infer potential difference from…

Liegeois, Laurent; Chasseigne, G'erard; Papin, Sophie; Mullet, Etienne

2003-01-01

81

Large endolymphatic potentials from low-frequency and infrasonic tones in the guinea pig.  

PubMed

Responses of the ear to low-frequency and infrasonic sounds have not been extensively studied. Understanding how the ear responds to low frequencies is increasingly important as environmental infrasounds are becoming more pervasive from sources such as wind turbines. This study shows endolymphatic potentials in the third cochlear turn from acoustic infrasound (5?Hz) are larger than from tones in the audible range (e.g., 50 and 500?Hz), in some cases with peak-to-peak amplitude greater than 20?mV. These large potentials were suppressed by higher-frequency tones and were rapidly abolished by perilymphatic injection of KCl at the cochlear apex, demonstrating their third-turn origins. Endolymphatic iso-potentials from 5 to 500?Hz were enhanced relative to perilymphatic potentials as frequency was lowered. Probe and infrasonic bias tones were used to study the origin of the enhanced potentials. Potentials were best explained as a saturating response summed with a sinusoidal voltage (Vo), that was phase delayed by an average of 60° relative to the biasing effects of the infrasound. Vo is thought to arise indirectly from hair cell activity, such as from strial potential changes caused by sustained current changes through the hair cells in each half cycle of the infrasound. PMID:23464026

Salt, Alec N; Lichtenhan, Jeffery T; Gill, Ruth M; Hartsock, Jared J

2013-03-01

82

Measurement of electrostatic potential fluctuation using heavy ion beam probe in large helical device  

SciTech Connect

Heavy ion beam probe (HIBP) for large helical device (LHD) has been improved to measure the potential fluctuation in high-temperature plasmas. The spatial resolution is improved to about 10 mm by controlling the focus of a probe beam. The HIBP is applied to measure the potential fluctuation in plasmas where the rotational transform is controlled by electron cyclotron current drive. The fluctuations whose frequencies change with the time constant of a few hundreds of milliseconds and that with a constant frequency are observed. The characteristics of the latter fluctuation are similar to those of the geodesic acoustic mode oscillation. The spatial profiles of the fluctuations are also obtained.

Ido, Takeshi; Shimizu, Akihiro; Nishiura, Masaki; Nakano, Haruhisa; Ohshima, Shinsuke; Kato, Shinji; Hamada, Yasuji; Yoshimura, Yasuo; Kubo, Shin; Shimozuma, Takashi; Igami, Hiroe; Takahashi, Hiromi; Toi, Kazuo; Watanabe, Fumitake [National Institute for Fusion Science, Gifu 509-5292 (Japan)

2008-10-15

83

Sagdeev potential approach for large amplitude compressional Alfvenic double layers in viscous plasmas  

SciTech Connect

Sagdeev’s technique is used to study the large amplitude compressional Alfvenic double layers in a magnetohydrodynamic plasma taking into account the small plasma ? and small values of kinematic viscosity. Dispersive effect raised by non-ideal electron inertia currents perpendicular to the ambient magnetic field. The range of allowed values of the soliton speed, M (Mach number), plasma ? (ratio of the plasma thermal pressure to the pressure in the confining magnetic field), and viscosity coefficient, wherein double layer may exist, are determined. In the absence of collisions, viscous dissipation modifies the Sagdeev potential and results in large amplitude compressional Alfvenic double layers. The depth of Sagdeev potential increases with the increasing Mach number and plasma ?, however, decreases with the increasing viscosity. The double layer structure increases with the increasing plasma ?, but decreases with increasing viscous dissipation ?(tilde sign)

Panwar, Anuraj; Rizvi, H.; Ryu, C. M. [Department of Physics, POSTECH, Hyoja-Dong San 31, Pohang, KyungBuk 790-784 (Korea, Republic of)] [Department of Physics, POSTECH, Hyoja-Dong San 31, Pohang, KyungBuk 790-784 (Korea, Republic of)

2013-11-15

84

Nonrelativistic variationally optimized exchange potentials for Ne-like atomic ions having large atomic number  

SciTech Connect

In an earlier study, the exchange energy density {epsilon}{sub x}(r) has been calculated analytically for Ne-like atomic ions in the nonrelativistic limit of large atomic number Z. Here, though now by numerical methods based on the optimized exchange potential approximation, corresponding results are obtained for V{sub x}(r) for such ten-electron ions at large Z. The approach to the bare Coulomb limiting form of the 1/Z expansion is considered in some detail, as are corrections to the Slater potential V{sub x}{sup Sl}(r), given in terms of the exchange energy density and ground-state density {rho}(r) by 2{epsilon}{sub x}(r)/{rho}(r)

Howard, I.A. [Department of Physics, University of Antwerp, Groenenborgerlaan 171, Antwerp (Belgium); March, N.H. [Department of Physics, University of Antwerp, Groenenborgerlaan 171, Antwerp (Belgium); Oxford University, Oxford (United Kingdom); Talman, J.D. [Department of Applied Mathematics, University of Western Ontario, London, Ontario (Canada)

2003-10-01

85

Sagdeev potential approach for large amplitude compressional Alfvenic double layers in viscous plasmas  

NASA Astrophysics Data System (ADS)

Sagdeev's technique is used to study the large amplitude compressional Alfvenic double layers in a magnetohydrodynamic plasma taking into account the small plasma ? and small values of kinematic viscosity. Dispersive effect raised by non-ideal electron inertia currents perpendicular to the ambient magnetic field. The range of allowed values of the soliton speed, M (Mach number), plasma ? (ratio of the plasma thermal pressure to the pressure in the confining magnetic field), and viscosity coefficient, wherein double layer may exist, are determined. In the absence of collisions, viscous dissipation modifies the Sagdeev potential and results in large amplitude compressional Alfvenic double layers. The depth of Sagdeev potential increases with the increasing Mach number and plasma ?, however, decreases with the increasing viscosity. The double layer structure increases with the increasing plasma ?, but decreases with increasing viscous dissipation ?˜.

Panwar, Anuraj; Rizvi, H.; Ryu, C. M.

2013-11-01

86

Study of potential cytoprotective activity of different antioxidants.  

PubMed

It is known that infiltration of atherosclerotic plaques by activated T lymphocytes occurs at the early stage and cytokines produced by those lymphocytes become actively involved in inflammatory process. Consequently the preparations, capable of stabilization of immune cells, perhaps will be effective for treatment and prevention of atherosclerosis. Intensively proliferated Jurkat leukemic T cell line (human leukemic cell culture) is widely used in scientific and Therapeutic research, as human T lymphocyte pattern. The aim of the study--To establish the cytoprotective action of different antioxidative preparations on Jurkat cells incubated in oxidative stress conditions. It was revealed the dose (100 microl, 50 microl) and time-related decrease of viability of Jurkat cells incubated in high oxidative stress conditions. Low doses of hydrogen peroxide (H(2)O(2)) (25 microl, 11 microl) present cytotoxicity only within short terms (8 hours). Vitamins C and E have cytotoxic effects on intact Jurkat cells separately; the activity of Megavite and Phenovin is not characterised by cytotoxicity. Incubation of Jurkat cells with antioxidants in moderate oxidative stress condition (H(2)O(2) 25 microl, 50 microl) all antioxidative preparations (except vitamin C) reveal static activity on viability of Jurkat cells. Incubation of Jurkat cells with antioxidants in intensive oxidative stress condition (H(2)O(2) 100 microl), the cytoprotective activity of antioxidative preparations was rather low. PMID:20157213

Ratiani, L; Ratiani, T; Sharashenidze, G; Janigashvili, G; Sanikidze, T

2010-01-01

87

Latency correction of event-related potentials between different experimental protocols  

NASA Astrophysics Data System (ADS)

Objective. A fundamental issue in EEG event-related potentials (ERPs) studies is the amount of data required to have an accurate ERP model. This also impacts the time required to train a classifier for a brain–computer interface (BCI). This issue is mainly due to the poor signal-to-noise ratio and the large fluctuations of the EEG caused by several sources of variability. One of these sources is directly related to the experimental protocol or application designed, and may affect the amplitude or latency of ERPs. This usually prevents BCI classifiers from generalizing among different experimental protocols. In this paper, we analyze the effect of the amplitude and the latency variations among different experimental protocols based on the same type of ERP. Approach. We present a method to analyze and compensate for the latency variations in BCI applications. The algorithm has been tested on two widely used ERPs (P300 and observation error potentials), in three experimental protocols in each case. We report the ERP analysis and single-trial classification. Main results. The results obtained show that the designed experimental protocols significantly affect the latency of the recorded potentials but not the amplitudes. Significance. These results show how the use of latency-corrected data can be used to generalize the BCIs, reducing the calibration time when facing a new experimental protocol.

Iturrate, I.; Chavarriaga, R.; Montesano, L.; Minguez, J.; Millán, JdR

2014-06-01

88

Latency correction of event-related potentials between different experimental protocols.  

PubMed

Objective. A fundamental issue in EEG event-related potentials (ERPs) studies is the amount of data required to have an accurate ERP model. This also impacts the time required to train a classifier for a brain-computer interface (BCI). This issue is mainly due to the poor signal-to-noise ratio and the large fluctuations of the EEG caused by several sources of variability. One of these sources is directly related to the experimental protocol or application designed, and may affect the amplitude or latency of ERPs. This usually prevents BCI classifiers from generalizing among different experimental protocols. In this paper, we analyze the effect of the amplitude and the latency variations among different experimental protocols based on the same type of ERP. Approach. We present a method to analyze and compensate for the latency variations in BCI applications. The algorithm has been tested on two widely used ERPs (P300 and observation error potentials), in three experimental protocols in each case. We report the ERP analysis and single-trial classification. Main results. The results obtained show that the designed experimental protocols significantly affect the latency of the recorded potentials but not the amplitudes. Significance. These results show how the use of latency-corrected data can be used to generalize the BCIs, reducing the calibration time when facing a new experimental protocol. PMID:24743234

Iturrate, I; Chavarriaga, R; Montesano, L; Minguez, J; Millán, JdR

2014-06-01

89

A complete and accurate surface-potential based large-signal model for compound semiconductor HEMTs  

NASA Astrophysics Data System (ADS)

A complete and accurate surface potential based large-signal model for compound semiconductor HEMTs is presented. A surface potential equation resembling the one used in conventional MOSFET models is achieved. The analytic solutions from the traditional surface potential theory that developed in MOSFET models are inherited. For core model derivation, a novel method is used to realize a direct application of the standard surface potential model of MOSFETs for HEMT modeling, without breaking the mathematic structure. The high-order derivatives of I—V/C—V remain continuous, making the model suitable for RF large-signal applications. Furthermore, the self-heating effects and the transconductance dispersion are also modelled. The model has been verified through comparison with measured DC IV, Gummel symmetry test, CV, minimum noise figure, small-signal S - parameters up to 66 GHz and single-tone input power sweep at 29 GHz for a 4 × 75 ?m × 0.1 ?m InGaAs/GaAs power pHEMT, fabricated at a commercial foundry.

Jun, Liu; Zhiping, Yu; Lingling, Sun

2014-03-01

90

Systematic study of the fusion barriers using different proximity-type potentials for N=Z colliding nuclei: New extensions  

SciTech Connect

By using 14 different versions and parametrizations of a proximity potential and two new versions of the potential proposed in this paper, we perform a comparative study of fusion barriers by studying 26 symmetric reactions. The mass asymmetry eta{sub A}=((A{sub 2}-A{sub 1}/A{sub 2}+A{sub 1})), however, is very large. Our detailed investigation reveals that most of the proximity potentials reproduce experimental data within +-8% on average. A comparison of fusion cross sections indicates that Bass 80, AW 95, and Denisov DP potentials have a better edge than other potentials. We also propose new versions of the proximity potential as well as Denisov parametrized potential. These new versions improve agreement with the data.

Dutt, Ishwar; Puri, Rajeev K. [Department of Physics, Panjab University, Chandigarh 160 014 (India)

2010-04-15

91

Epidemiology of Trauma: Frequency and Impact of Different Potentially Traumatic Events on Different Demographic Groups.  

ERIC Educational Resources Information Center

Examined frequency/impact of 10 potentially traumatic events among 1,000 adults. Tragic death occurred most often, sexual assault yielded highest rate of posttraumatic stress disorder, and motor vehicle crash presented most adverse combination of frequency and impact. Lifetime exposure was higher among whites and men than among African Americans…

Norris, Fran H.

1992-01-01

92

Dendritic cells derived from pluripotent stem cells: Potential of large scale production.  

PubMed

Human pluripotent stem cells (hPSCs), including human embryonic stem cells and human induced pluripotent stem cells, are promising sources for hematopoietic cells due to their unlimited growth capacity and the pluripotency. Dendritic cells (DCs), the unique immune cells in the hematopoietic system, can be loaded with tumor specific antigen and used as vaccine for cancer immunotherapy. While autologous DCs from peripheral blood are limited in cell number, hPSC-derived DCs provide a novel alternative cell source which has the potential for large scale production. This review summarizes recent advances in differentiating hPSCs to DCs through the intermediate stage of hematopoietic stem cells. Step-wise growth factor induction has been used to derive DCs from hPSCs either in suspension culture of embryoid bodies (EBs) or in co-culture with stromal cells. To fulfill the clinical potential of the DCs derived from hPSCs, the bioprocess needs to be scaled up to produce a large number of cells economically under tight quality control. This requires the development of novel bioreactor systems combining guided EB-based differentiation with engineered culture environment. Hence, recent progress in using bioreactors for hPSC lineage-specific differentiation is reviewed. In particular, the potential scale up strategies for the multistage DC differentiation and the effect of shear stress on hPSC differentiation in bioreactors are discussed in detail. PMID:24567783

Li, Yan; Liu, Meimei; Yang, Shang-Tian

2014-01-26

93

Probing internucleus potential with large-angle quasi-elastic scattering  

NASA Astrophysics Data System (ADS)

Recent measurements for fusion cross section at energies around the Coulomb barrier have systematically indicated a significant deviation of fusion cross sections from a prediction of double-folding model. It has been argued that the deviation can be accounted for if one uses a large value of surface diffuseness parameter for a Woods-Saxon internuclear potential. We investigate this problem using large-angle quasi-elastic scattering, that is a good counterpart of fusion reaction. Towards a reconciliation of the apparent anomaly in the diffuseness parameter for fusion reactions, we also discuss possible ingredients which are missing in present nuclear reaction models. Those include a deviation from the frozen density approximation, the effect of antisymmetrization and the role of coordinate dependent moment of inertia for the relative motion between the colliding nuclei.

Hagino, K.; Washiyama, K.

2006-08-01

94

Exploring the potential energy landscape over a large parameter-space  

NASA Astrophysics Data System (ADS)

Solving large polynomial systems with coefficient parameters are ubiquitous and constitute an important class of problems. We demonstrate the computational power of two methods — a symbolic one called the Comprehensive Gröbner basis and a numerical one called coefficient-parameter polynomial continuation — applied to studying both potential energy landscapes and a variety of questions arising from geometry and phenomenology. Particular attention is paid to an example in flux compactification where important physical quantities such as the gravitino and moduli masses and the string coupling can be efficiently extracted.

He, Yang-Hui; Mehta, Dhagash; Niemerg, Matthew; Rummel, Markus; Valeanu, Alexandru

2013-07-01

95

Generation, migration, and resource potential for hydrocarbons in accretionary subduction systems - a large, unconventional hydrocarbon resource  

SciTech Connect

Methane and other gaseous and liquid hydrocarbons are common components of accretionary complexes and have been observed in all environments within modern and fossil accretionary accumulations. Methane is generated in this setting by both microbial and thermal processes, but the limited number of samples analyzed prevents an accurate assessment of the relative importance of these two gas generation mechanisms. Large accretionary prisms are geologic settings which, owing to the large amounts of organic detritus cycling through them, represent a large potential source of methane. Organic detritus in accretionary systems is primarily terrestrial in origin and thus gas prone. Variations in the sediment input, thermal structure, fluid flow regime, and structural style of accretionary prisms have a substantial effect on the amount of sediment that enters the gas generation window and on the amount and type of hydrocarbons generated. Factors favorable for maximum evolution of gas include a large, thick accretionary prism, a thick incoming sedimentary section, substantial axial trench sedimentation fed with continental detritus, development of the decollement near the top of the incoming section, substantial underplating, a young subducting plate, and slow to moderate plate convergence rates. On a worldwide basis, long-term methane generation potential is estimated at 1.5x10[sup 10] m[sup 3] (0.5 trillion cubic feet or Tcf) per year in the accretionary subduction setting. No commercial accumulations of gas have yet been identified in this setting; this lack of accumulations implies that much of the gas generated may escape to the oceans and the atmosphere. However, accretionary complexes have not been extensively explored for hydrocarbons, and the trapping of even a small part of the gas generated could result in a substantial commercial resource. 37 refs., 5 figs.

Stevenson, A.J. (Geological Survey, Menlo Park, CA (United States))

1993-01-01

96

Measurement and definition of changes in the visual evoked potential to different stimulus intensities.  

PubMed

Visual evoked potentials (VEPs) were recorded from the vertex to 5 intensities of light flashes. Measures were taken of peak-to-trough, prestimulus baseline-to-peak, and timeband amplitude for P1, N1, and P2 waveforms. Augmenting/reducing was defined by traditional (amplitude/intensity slope, monotonicity) and non-traditional (strength of the nervous system, combined amplitude response) criteria. In support of Connolly and Gruzelier ([1982) Psychophysiology, 19: 599-608], analyses showed that data collected by traditional methods contravened assumptions underlying VEP augmenting/reducing methodology. Specifically, 20% of total peaks occurred outside designated timebands, amplitude/intensity slopes explained only 30-46% variance, and levels of agreement between different definitions were low. Researchers ought to ensure that VEPs are admissible before using them or consider employing non-traditional criteria to avoid rejecting large numbers of inadmissible data. PMID:3610728

Dragutinovich, S

1987-07-01

97

Large age differences between planktic foraminifers caused by abundance variations and Zoophycos bioturbation  

NASA Astrophysics Data System (ADS)

The downward transport of surface sediment deep into the sediment column by the Zoophycos-producing animal leads not only to large age differences between the Zoophycos structure and surrounding host sediment but also to large differences in age between different foraminifer species found inside the trace fossil. In the late Quaternary material from the southwestern Portuguese continental slope examined in this study, age differences of up to 2590 years were observed between the planktic foraminifer species Globigerinoides ruber and Globigerina bulloides. These differences are caused by the mixing of surface and host material with different abundances of the two species. If there are differences in the abundance of the two species at the surface and/or in the host sediment, plenty of relatively young foraminifers may be mixed with few relatively old ones, or vice versa. The age differences between species caused by the combination of deep-reaching bioturbation by the Zoophycos producer and abundance variations may be considerably larger than the age differences caused by the homogenizing bioturbation in the mixed layer.

LöWemark, Ludvig; Grootes, Pieter M.

2004-06-01

98

Are solar gamma-ray-line flares different from other large flares?  

NASA Technical Reports Server (NTRS)

We reevaluate evidence indicating that gamma-ray-line (GRL) flares are fundamentally different from other large flares without detectable GRL emission and find no compelling support for this proposition. For large flares observed by the Solar Maximum Mission (SMM) from 1980 to 1982, we obtain a reasonably good correlation between 4-8 MeV GRL fluences and greater than 50 keV hard X-ray fluences and find no evidence for a distinct population of large hard X-ray flares that lack commensurate GRL emission. Our results are consistent with the acceleration of the bulk of the approximately 100 keV electrons and approximately 10 MeV protons (i.e., the populations of these species that interact in the solar atmosphere to produce hard X-ray and GRL emission) by a common process in large flares of both long and short durations.

Cliver, E. W.; Crosby, N. B.; Dennis, B. R.

1994-01-01

99

Strategy Differences Among Small and Large Firms in a Technology Intensive Industry  

Microsoft Academic Search

Empirical research has shown that new, small, highly innovative firms have greater job creation rates than low innovation firms. In spite of this knowledge, it is not known how small firms differ from large firms in highly innovative industries. This paper describes results of a su r- vey of firms operating in the MEMS industry, an emerging high technology industry

Steven T. Walsh; Bruce A. Kirchhoff; Marylouise K. Dowd

100

Infants Use Different Mechanisms to Make Small and Large Number Ordinal Judgments  

ERIC Educational Resources Information Center

Previous research has shown indirectly that infants may use two different mechanisms-an object tracking system and an analog magnitude mechanism--to represent small (less than 4) and large (greater than or equal to 4) numbers of objects, respectively. The current study directly tested this hypothesis in an ordinal choice task by presenting 10- to…

vanMarle, Kristy

2013-01-01

101

Prediction model of potential hepatocarcinogenicity of rat hepatocarcinogens using a large-scale toxicogenomics database  

Microsoft Academic Search

The present study was performed to develop a robust gene-based prediction model for early assessment of potential hepatocarcinogenicity of chemicals in rats by using our toxicogenomics database, TG-GATEs (Genomics-Assisted Toxicity Evaluation System developed by the Toxicogenomics Project in Japan). The positive training set consisted of high- or middle-dose groups that received 6 different non-genotoxic hepatocarcinogens during a 28-day period. The

Takeki Uehara; Yohsuke Minowa; Yuji Morikawa; Chiaki Kondo; Toshiyuki Maruyama; Ikuo Kato; Noriyuki Nakatsu; Yoshinobu Igarashi; Atsushi Ono; Hitomi Hayashi; Kunitoshi Mitsumori; Hiroshi Yamada; Yasuo Ohno; Tetsuro Urushidani

2011-01-01

102

Large particle multiphoton flow cytometry to purify intact embryoid bodies exhibiting enhanced potential for cardiomyocyte differentiation.  

PubMed

Embryoid bodies (EBs) are large (>100 ?m) 3D microtissues composed of stem cells, differentiating cells and extracellular matrix (ECM) proteins that roughly recapitulate early embryonic development. EBs are widely used as in vitro model systems to study stem cell differentiation and the complex physical and chemical interactions contributing to tissue development. Though much has been learned about differentiation from EBs, the practical and technical difficulties of effectively probing and properly analyzing these 3D microtissues has limited their utility and further application. We describe advancement of a technology platform developed in our laboratory, multiphoton flow cytometry (MPFC), to detect and sort large numbers of intact EBs based on size and fluorescent reporters. Real-time and simultaneous measurement of size and fluorescence intensity are now possible, through the implementation of image processing algorithms in the MPFC software. We applied this platform to purify populations of EBs generated from murine induced pluripotent stem (miPS) cells exhibiting enhanced potential for cardiomyocyte differentiation either as a consequence of size or expression of NKX2-5, a homeodomain protein indicative of precardiac cells. Large EBs (330-400 ?m, diameter) purified soon after EB formation showed significantly higher potential to form cardiomyocytes at later time points than medium or small EBs. In addition, EBs expressing NKX2-5 soon after EB formation were more likely to form beating areas, indicative of cardiomyocyte differentiation, at later time points. Collectively, these studies highlight the ability of the MPFC to purify EBs and similar microtissues based on preferred features exhibited at the time of sorting or on features indicative of future characteristics or functional capacity. PMID:23759950

Buschke, D G; Vivekanandan, A; Squirrell, J M; Rueden, C T; Eliceiri, K W; Ogle, B M

2013-07-24

103

Dorsolateral medullary infarction: a neurogenic cause of a contralateral, large-amplitude vestibular evoked myogenic potential.  

PubMed

The vestibular evoked myogenic potential (VEMP) has become a useful tool to assess the saccule and inferior vestibular nerve function. Vestibulopathies involving the saccule or inferior vestibular nerve typically result in VEMP responses that are diminished or absent on the involved side. Abnormally large VEMPs are rare. Large VEMPs have been associated with superior canal dehiscence, Ménière's disease, and labyrinthine fistula. In all of these cases, the abnormally large VEMP can be explained on the basis of labyrinthine hydromechanical changes that result in excessive saccular displacement in response to intense sound. In this report, a case is presented of a 74-year-old male with dorsal lateral medullary infarction (Wallenberg's syndrome) who presented with an enlarged VEMP--a finding that has not been reported to date as a result of a brain stem lesion. Particularly perplexing, the enlarged VEMP was on the contralesional side. A proposed mechanism of contralateral vestibular nuclei disinhibition secondary to the brain stem stroke is discussed. PMID:18672653

Lundy, Larry; Zapala, David; Olsholt, Ketil

2008-03-01

104

Nonhost Resistance of Barley to Different Fungal Pathogens Is Associated with Largely Distinct, Quantitative Transcriptional Responses1[W][OA  

PubMed Central

Nonhost resistance protects plants against attack by the vast majority of potential pathogens, including phytopathogenic fungi. Despite its high biological importance, the molecular architecture of nonhost resistance has remained largely unexplored. Here, we describe the transcriptional responses of one particular genotype of barley (Hordeum vulgare subsp. vulgare ‘Ingrid’) to three different pairs of adapted (host) and nonadapted (nonhost) isolates of fungal pathogens, which belong to the genera Blumeria (powdery mildew), Puccinia (rust), and Magnaporthe (blast). Nonhost resistance against each of these pathogens was associated with changes in transcript abundance of distinct sets of nonhost-specific genes, although general (not nonhost-associated) transcriptional responses to the different pathogens overlapped considerably. The powdery mildew- and blast-induced differences in transcript abundance between host and nonhost interactions were significantly correlated with differences between a near-isogenic pair of barley lines that carry either the Mlo wild-type allele or the mutated mlo5 allele, which mediates basal resistance to powdery mildew. Moreover, during the interactions of barley with the different host or nonhost pathogens, similar patterns of overrepresented and underrepresented functional categories of genes were found. The results suggest that nonhost resistance and basal host defense of barley are functionally related and that nonhost resistance to different fungal pathogens is associated with more robust regulation of complex but largely nonoverlapping sets of pathogen-responsive genes involved in similar metabolic or signaling pathways.

Zellerhoff, Nina; Himmelbach, Axel; Dong, Wubei; Bieri, Stephane; Schaffrath, Ulrich; Schweizer, Patrick

2010-01-01

105

Potential for on-orbit manufacture of large space structures using the pultrusion process  

NASA Technical Reports Server (NTRS)

On-orbit manufacture of lightweight, high-strength, advanced-composite structures using the pultrusion process is proposed. This process is adaptable to a zero-gravity environment by using preimpregnated graphite-fiber reinforcement systems. The reinforcement material is preimpregnated with a high-performance thermoplastic resin at a ground station, is coiled on spools for compact storage, and is transported into Earth orbit. A pultrusion machine is installed in the Shuttle cargo bay from which very long lengths of the desired structure is fabricated on-orbit. Potential structural profiles include rods, angles, channels, hat sections, tubes, honeycomb-cored panels, and T, H, and I beams. A potential pultrudable thermoplastic/graphite composite material is presented as a model for determining the effect on Earth-to-orbit package density of an on-orbit manufacture, the package density is increased by 132 percent, and payload volume requirement is decreased by 56.3 percent. The fabrication method has the potential for on-orbit manufacture of structural members for space platforms, large space antennas, and long tethers.

Wilson, Maywood L.; Macconochie, Ian O.; Johnson, Gary S.

1987-01-01

106

Fatty acid profiles of muscle from large yellow croaker (Pseudosciaena crocea R.) of different age  

PubMed Central

We investigated the fatty acid profiles of muscle from large yellow croaker (Pseudosciaena crocea R.) of different age. One- and two-year-old fish were cultured in floating net cages and sampled randomly for analysis. Moisture, protein, lipid and ash contents were determined by methods of Association of Analytical Chemist (AOAC) International. Fatty acid profile was determined by gas chromatography. Crude protein, fat, moisture and ash contents showed no significant differences between the two age groups. The contents of total polyunsaturated fatty acids and docosahexaenoic acid (DHA) were significantly higher and eicosapentaenoic acid (EPA) content was significantly lower in the two-year-old large yellow croaker than in the one-year-old (P<0.05). No significant differences were observed in the contents of total saturated fatty acids and monounsaturated fatty acids, or the ratio of n-3/n-6 fatty acids among the large yellow croakers of the two age groups. We conclude that large yellow croakers are good food sources of EPA and DHA.

Tang, Hong-gang; Chen, Li-hong; Xiao, Chao-geng; Wu, Tian-xing

2009-01-01

107

Beyond-mean-field behavior of large Bose-Einstein condensates in double-well potentials  

NASA Astrophysics Data System (ADS)

For the dynamics of Bose-Einstein condensates (BECs), differences between mean-field (Gross-Pitaevskii) physics and N-particle quantum physics often disappear if the BEC becomes larger and larger. In particular, the time scale for which both dynamics agree should thus become larger if the particle number increases. For BECs in a double-well potential, we find both examples for which this is the case and examples for which differences remain even for huge BECs on experimentally realistic short time scales. By using a combination of numerical and analytical methods, we show that the differences remain visible on the level of expectation values even beyond the largest possible numbers realized experimentally for BECs with ultracold atoms.

Gertjerenken, Bettina; Weiss, Christoph

2013-09-01

108

Precipitating electron fluxes formed by a magnetic field aligned potential difference  

Microsoft Academic Search

A model is developed in which a magnetic field aligned potential difference is assumed to accelerate electrons downward into the atmosphere. It is pointed out that the upgoing backscattered electrons produced by this electron beam may process insufficient kinetic energy to overcome the hypothetical potential difference. These electrons will be reflected downward to appear as members of a precipitating electron

David S. Evans

1974-01-01

109

Potential and attainable food production and food security in different regions  

PubMed Central

Growing prosperity in the South is accompanied by human diets that will claim more natural resources per capita. This reality, combined with growing populations, may raise the global demand for food crops two- to four-fold within two generations. Considering the large volume of natural resources and potential crop yields, it seems that this demand can be met smoothly. However, this is a fallacy for the following reasons. (i) Geographic regions differ widely in their potential food security: policy choices for agricultural use of natural resources are limited in Asia. For example, to ensure national self-sufficiency and food security, most of the suitable land (China) and nearly all of the surface water (India) are needed. Degradation restricts options further. (ii) The attainable level of agricultural production depends also on socio-economic conditions. Extensive poverty keeps the attainable food production too low to achieve food security, even when the yield gap is wide, as in Africa. (iii) Bio-energy, non-food crops and nature compete with food crops for natural resources. Global and regional food security are attainable, but only with major efforts. Strategies to achieve alternative aims will be discussed.

Vries, F. W. T. Penning de; Rabbinge, R.; Groot, J. J. R.

1997-01-01

110

On the Definition of Surface Potentials for Finite-Difference Operators  

NASA Technical Reports Server (NTRS)

For a class of linear constant-coefficient finite-difference operators of the second order, we introduce the concepts similar to those of conventional single- and double-layer potentials for differential operators. The discrete potentials are defined completely independently of any notion related to the approximation of the continuous potentials on the grid. We rather use all approach based on differentiating, and then inverting the differentiation of a function with surface discontinuity of a particular kind, which is the most general way of introducing surface potentials in the theory of distributions. The resulting finite-difference "surface" potentials appear to be solutions of the corresponding continuous potentials. Primarily, this pertains to the possibility of representing a given solution to the homogeneous equation on the domain as a variety of surface potentials, with the density defined on the domain's boundary. At the same time the discrete surface potentials can be interpreted as one specific realization of the generalized potentials of Calderon's type, and consequently, their approximation properties can be studied independently in the framework of the difference potentials method by Ryaben'kii. The motivation for introducing and analyzing the discrete surface potentials was provided by the problems of active shielding and control of sound, in which the aforementioned source terms that drive the potentials are interpreted as the acoustic control sources that cancel out the unwanted noise on a predetermined region of interest.

Tsynkov, S. V.; Bushnell, Dennis M. (Technical Monitor)

2001-01-01

111

Solid lipid nanoparticles: continuous and potential large-scale nanoprecipitation production in static mixers.  

PubMed

This work aimed at developing continuous and scalable nanoprecipitation synthesis of solid lipid nanoparticles (SLN) by mixing lipids acetonic solution with water using static mixers. The developed platform exhibited good control over the nanoprecipitation process and enabled the production of SLN below 200 nm at a throughput of 37.5-150 g/h (for 25 mg/ml lipid solution at a flow rate of 25-100 ml/min). Among the several process parameters investigated, the lipid concentration played primary role in influencing the size of the SLN and higher lipid concentration resulted in relatively larger particles. Fenofibrate, a model drug, has been successfully loaded into the SLN. Our work demonstrates the potential of applying static mixing-nanoprecipitation for continuous and large scale production of SLN. PMID:22326649

Dong, Yuancai; Ng, Wai Kiong; Shen, Shoucang; Kim, Sanggu; Tan, Reginald B H

2012-06-01

112

A Study of Contact Binaries with Large Temperature Differences between Components  

NASA Astrophysics Data System (ADS)

We present an extensive analysis of new light and radial velocity (RV) curves, as well as high quality broadening function (BF) profiles of twelve binary systems for which a contact configuration with large temperature differences between components has been reported in the literature. We find that six systems (V1010 Oph, WZ Cyg, VV Cet, DO Cas, FS Lup, V747 Cen) have near contact configurations. For the remaining systems (CX Vir, FT Lup, BV Eri, FO Hya, CN And, BX And), our solutions of the new observations once again converge in a contact configuration with large temperature differences between the components. However, the bright regions discovered in the BFs for V747 Cen, CX Vir, FT Lup, BV Eri, FO Hya, and CN And, and further attributed to hot spots, shed new light on the physical processes taking place between the components and imply the possibility that the contact configurations obtained from light and RV curve modeling are a spurious result.

Siwak, M.; Zola, S.; Koziel-Wierzbowska, D.

2010-12-01

113

Intra- and interspecific differences in diet quality and composition in a large herbivore community.  

PubMed

Species diversity in large herbivore communities is often explained by niche segregation allowed by differences in body mass and digestive morphophysiological features. Based on large number of gut samples in fall and winter, we analysed the temporal dynamics of diet composition, quality and interspecific overlap of 4 coexisting mountain herbivores. We tested whether the relative consumption of grass and browse differed among species of different rumen types (moose-type and intermediate-type), whether diet was of lower quality for the largest species, whether we could identify plant species which determined diet quality, and whether these plants, which could be "key-food-resources" were similar for all herbivores. Our analyses revealed that (1) body mass and rumen types were overall poor predictors of diet composition and quality, although the roe deer, a species with a moose-type rumen was confirmed as an "obligatory non grazer", while red deer, the largest species, had the most lignified diet; (2) diet overlap among herbivores was well predicted by rumen type (high among species of intermediate types only), when measured over broad plant groups, (3) the relationship between diet composition and quality differed among herbivore species, and the actual plant species used during winter which determined the diet quality, was herbivore species-specific. Even if diets overlapped to a great extent, the species-specific relationships between diet composition and quality suggest that herbivores may select different plant species within similar plant group types, or different plant parts and that this, along with other behavioural mechanisms of ecological niche segregation, may contribute to the coexistence of large herbivores of relatively similar body mass, as observed in mountain ecosystems. PMID:24586233

Redjadj, Claire; Darmon, Gaëlle; Maillard, Daniel; Chevrier, Thierry; Bastianelli, Denis; Verheyden, Hélène; Loison, Anne; Saïd, Sonia

2014-01-01

114

A multigrid method for natural convective heat transfer with large temperature differences  

Microsoft Academic Search

Steady-state two-dimensional solutions to the full compressible Navier–Stokes equations are computed for laminar convective motion of a gas in a square cavity with large horizontal temperature differences. Results for air are presented. The ideal-gas law is used and viscosity is given by Sutherland's law. An accurate low-Mach number solver is developed. Hereby an explicit third-order discretization for the convective part

Jan Vierendeels; Bart Merci; Erik Dick

2004-01-01

115

Potential consequences of climate change for primary production and fish production in large marine ecosystems.  

PubMed

Existing methods to predict the effects of climate change on the biomass and production of marine communities are predicated on modelling the interactions and dynamics of individual species, a very challenging approach when interactions and distributions are changing and little is known about the ecological mechanisms driving the responses of many species. An informative parallel approach is to develop size-based methods. These capture the properties of food webs that describe energy flux and production at a particular size, independent of species' ecology. We couple a physical-biogeochemical model with a dynamic, size-based food web model to predict the future effects of climate change on fish biomass and production in 11 large regional shelf seas, with and without fishing effects. Changes in potential fish production are shown to most strongly mirror changes in phytoplankton production. We project declines of 30-60% in potential fish production across some important areas of tropical shelf and upwelling seas, most notably in the eastern Indo-Pacific, the northern Humboldt and the North Canary Current. Conversely, in some areas of the high latitude shelf seas, the production of pelagic predators was projected to increase by 28-89%. PMID:23007086

Blanchard, Julia L; Jennings, Simon; Holmes, Robert; Harle, James; Merino, Gorka; Allen, J Icarus; Holt, Jason; Dulvy, Nicholas K; Barange, Manuel

2012-11-01

116

Potential consequences of climate change for primary production and fish production in large marine ecosystems  

PubMed Central

Existing methods to predict the effects of climate change on the biomass and production of marine communities are predicated on modelling the interactions and dynamics of individual species, a very challenging approach when interactions and distributions are changing and little is known about the ecological mechanisms driving the responses of many species. An informative parallel approach is to develop size-based methods. These capture the properties of food webs that describe energy flux and production at a particular size, independent of species' ecology. We couple a physical–biogeochemical model with a dynamic, size-based food web model to predict the future effects of climate change on fish biomass and production in 11 large regional shelf seas, with and without fishing effects. Changes in potential fish production are shown to most strongly mirror changes in phytoplankton production. We project declines of 30–60% in potential fish production across some important areas of tropical shelf and upwelling seas, most notably in the eastern Indo-Pacific, the northern Humboldt and the North Canary Current. Conversely, in some areas of the high latitude shelf seas, the production of pelagic predators was projected to increase by 28–89%.

Blanchard, Julia L.; Jennings, Simon; Holmes, Robert; Harle, James; Merino, Gorka; Allen, J. Icarus; Holt, Jason; Dulvy, Nicholas K.; Barange, Manuel

2012-01-01

117

Cryptosporidium parvum possesses a short-type replication protein A large subunit that differs from its host.  

PubMed

Replication protein A (RPA) consisting of three subunits is a eukaryotic single-stranded DNA (ssDNA)-binding protein involved in DNA replication, repair and recombination. We report here the identification and characterization of a RPA large subunit (CpRPA1) gene from the apicomplexan Cryptosporidium parvum. The CpRPA1 gene encodes a 53.9-kDa peptide that is remarkably smaller than that from other eukaryotes (i.e. approximately 70 kDa) and is actively expressed in both free sporozoites and parasite intracellular stages. This short-type RPA large subunit has also been characterized from one other protist, Crithidia fasciculata. Three distinct domains have been identified in the RPA large subunit of humans and yeasts: an N-terminal protein interaction domain, a central ssDNA-binding area, and a C-terminal subunit-interacting region. Sequence analysis reveals that the short-type RPA large subunit differs from that of other eukaryotes in that only the domains required for ssDNA binding and heterotrimer formation are present. It lacks the N-terminal domain necessary for the binding of proteins mainly involved in DNA repair and recombination. This major structural difference suggests that the mechanism for DNA repair and recombination in some protists differs from that of other eukaryotes. Since replication proteins play an essential role in the cell cycle, the fact that RPA proteins of C. parvum differ from those of its host suggests that RPA be explored as a potential chemotherapeutic target for controlling cryptosporidiosis and/or diseases caused by other apicomplexans. PMID:10427719

Zhu, G; Marchewka, M J; Keithly, J S

1999-07-15

118

Effect of human gastrin infusion on gastric potential difference in man.  

PubMed

Human gastrin I heptadecapeptide, infused intravenously to healthy volunteers in a dose of 0.5 micrograms/kg/hr, caused a prompt, significant reduction in gastric potential difference (decrease of mucosal negativity), with the peak change at 6 min. This decline in potential difference occurred at a time when the serum gastrin level was between 24 and 83 pg/ml; at the same time, scanning electron microscopic examination of fractographs of parietal cells demonstrated marked increase in canalicular membrane area. This study shows that the decrease in potential difference after gastrin occurs with serum gastrin levels which are in the physiologic range. PMID:7438958

Tarnawski, A; McGuigan, J E; Ivey, K J

1980-11-01

119

The Potential of Unmanned Aerial Vehicle for Large Scale Mapping of Coastal Area  

NASA Astrophysics Data System (ADS)

Many countries in the tropical region are covered with cloud for most of the time, hence, it is difficult to get clear images especially from high resolution satellite imagery. Aerial photogrammetry can be used but most of the time the cloud problem still exists. Today, this problem could be solved using a system known as unmanned aerial vehicle (UAV) where the aerial images can be acquired at low altitude and the system can fly under the cloud. The UAV system could be used in various applications including mapping coastal area. The UAV system is equipped with an autopilot system and automatic method known as autonomous flying that can be utilized for data acquisition. To achieve high resolution imagery, a compact digital camera of high resolution was used to acquire the aerial images at an altitude. In this study, the UAV system was employed to acquire aerial images of a coastal simulation model at low altitude. From the aerial images, photogrammetric image processing was executed to produce photogrammetric outputs such a digital elevation model (DEM), contour line and orthophoto. In this study, ground control point (GCP) and check point (CP) were established using conventional ground surveying method (i.e total station). The GCP is used for exterior orientation in photogrammetric processes and CP for accuracy assessment based on Root Mean Square Error (RMSE). From this study, it was found that the UAV system can be used for large scale mapping of coastal simulation model with accuracy at millimeter level. It is anticipated that the same system could be used for large scale mapping of real coastal area and produces good accuracy. Finally, the UAV system has great potential to be used for various applications that require accurate results or products at limited time and less man power.

Darwin, N.; Ahmad, A.; Zainon, O.

2014-02-01

120

Magnetic analytic bond-order potential for modeling the different phases of Mn at zero Kelvin  

NASA Astrophysics Data System (ADS)

It is known that while group VII 4d Tc and 5d Re have hexagonally close-packed (hcp) ground states, 3d Mn adopts a complex ?-phase ground state, exhibiting complex noncollinear magnetic ordering. Density functional theory (DFT) calculations have shown that without magnetism, the ? phase is still the ground state of Mn implying that magnetism and the resultant atomic-size difference between large- and small-moment atoms are not the critical factors, as is commonly believed, in driving the anomalous stability of the ? phase over hcp. Using a canonical tight-binding (TB) model, it is found that for a more than half-filled d band, while harder potentials stabilize close-packed hcp, a softer potential stabilizes the more open ? phase. By analogy with the structural trend from open to close-packed phases down the group IV elements, the anomalous stability of the ? phase in Mn is shown to be due to 3d valent Mn lacking d states in the core which leads to an effectively softer atomic repulsion between the atoms than in 4d Tc and 5d Re. Subsequently, an analytic bond-order potential (BOP) is developed to investigate the structural and magnetic properties of elemental Mn at 0 K. It is derived within BOP theory directly from a new short-ranged orthogonal d-valent TB model of Mn, the parameters of which are fitted to reproduce the DFT binding energy curves of the four experimentally observed phases of Mn, namely, ?, ?, ?, ?, and ?-Mn. Not only does the BOP reproduce qualitatively the DFT binding energy curves of the five different structure types, it also predicts the complex collinear antiferromagnetic (AFM) ordering in ?-Mn, the ferrimagnetic ordering in ?-Mn, and the AFM ordering in ?-, ?-, and ?-Mn that are found by DFT. A BOP expansion including 14 moments is sufficiently converged to reproduce most of the properties of the TB model with the exception of the elastic shear constants, which require further moments. The current TB model, however, predicts values of the shear moduli and the vacancy formation energies that are approximately a factor of 2 too small, so that a future more realistic model for MD simulations will require these properties to be included from the outset in the fitting database.

Drain, John F.; Drautz, Ralf; Pettifor, D. G.

2014-04-01

121

Anomalously large difference in dipole moment of isomers with nearly identical thermodynamic stability.  

PubMed

Sulfuric acid is a primary atmospheric nucleation precursor, with the ability to form stable aqueous hydrogen-bonded clusters/complexes. The electrical dipole moment of such clusters/complexes is important for ion-induced nucleation, largely controlled by dipole-charge interaction of airborne ions with vapor monomers and pre-existing clusters. Although experiments typically trace a single lowest energy conformer at low temperatures, the present study shows that the immediate vicinity (<1 kcal mol (-1)) of the global minima may be populated with a number of isomers of nearly identical spectral characteristics and drastically different dipole moments. The difference in the dipole moment of mono-, di-, and trihydrates of the sulfuric acid exceeds 1.3-1.5 Debyes ( approximately 50-60%), 1.4-2.6 Debyes ( approximately 50-90%), and 3.8-4.2 Debyes ( approximately 370-550%), respectively. Being driven by the temperature dependence of the Boltzmann distribution, the difference between the Boltzmann-Gibbs average dipole moment and the dipole moment of the most stable isomer increases with the ambient temperature, leading to large variations in the dipole-ion interaction strength, which may have important implications for the ion-mediated production of ultrafine aerosol particles associated with various climatic and health impacts. PMID:18636695

Nadykto, Alexey B; Yu, Fangqun

2008-08-01

122

Site-directed mutants of pseudoazurin: explanation of increased redox potentials from X-ray structures and from calculation of redox potential differences.  

PubMed

In order to understand the origins of differences in redox potentials among cupredoxins (small blue type I copper-containing proteins that reversibly change oxidation state and interact with redox partners), we have determined the structures of the native and two mutants (P80A and P80I) of pseudoazurin from Alcaligenes faecalis S-6 in oxidized and reduced forms at resolutions of 2.2 A in the worst case and 1.6 A in the best case. The P80A mutation creates a surface pocket filled by a new water molecule, whereas the P80I mutant excludes this water. Distinct patterns of change occur in response to reduction for all three molecules: the copper position shifts, Met 7 and Pro 35 move, and the relative orientations of residues 81 to 16, 18 to the amide planes of 77 and 86, all change. Systematic changes in the weak electrostatic interactions seen in the structures of different oxidation states can explain the Met 7/Pro 35 structural differences as well as some fluctuating solvent positions. Overall displacement parameters increase reversibly upon reduction. The reduced forms are slightly expanded over the oxidized forms. The geometries of the mutants become more trigonal in their reduced forms, consistent with higher redox potentials (+409 mV for P80A and +450 mV for P80I). Calculations of the differences in redox potentials, using POLARIS, reveal that a water unique to the P80A mutant is required (with correctly oriented hydrogens) to approximate the observed difference in redox potential. The POLARIS calculations suggest that the reduced forms are additionally stabilized through changes in the solvation of the copper center, specifically via the amides of residues 16, 39, 41, 79, and 80 which interact with either Phe 18, Met 86, or Cys 78. The redox potential of P80A is increased largely due to solvation effects, whereas the redox potential of P80I is increased largely due to geometrical effects. PMID:9341204

Libeu, C A; Kukimoto, M; Nishiyama, M; Horinouchi, S; Adman, E T

1997-10-28

123

Automatic Crack Measuring System Using the Direct-Current Potential-Difference Method.  

National Technical Information Service (NTIS)

This report describes the development of a computer controlled direct-current potential-difference crack measuring system and its application to obtain crack growth rate data from centre-cracked-tension specimens. Details of the hardware and the software ...

G. W. Revill M. Findlay

1985-01-01

124

Different Anaphoric Expressions Are Investigated by Event-Related Brain Potentials  

ERIC Educational Resources Information Center

Event-related potentials were recorded to substantiate the claim of a distinct psycholinguistic status of (a) pronouns vs. proper names and (b) ellipses vs. proper names. In two studies 41 students read sentences in which the number of intervening words between the anaphor and its antecedent was either small or large. Comparing the far with the…

Streb, Judith; Hennighausen, Erwin; Rosler, Frank

2004-01-01

125

Mirror Energy Differences at Large Isospin Studied through Direct Two-Nucleon Knockout  

NASA Astrophysics Data System (ADS)

The first spectroscopy of excited states in Ni52 (Tz=-2) and Co51 (Tz=-3/2) has been obtained using the highly selective two-neutron knockout reaction. Mirror energy differences between isobaric analogue states in these nuclei and their mirror partners are interpreted in terms of isospin nonconserving effects. A comparison between large-scale shell-model calculations and data provides the most compelling evidence to date that both electromagnetic and an additional isospin nonconserving interactions for J=2 couplings, of unknown origin, are required to obtain good agreement.

Davies, P. J.; Bentley, M. A.; Henry, T. W.; Simpson, E. C.; Gade, A.; Lenzi, S. M.; Baugher, T.; Bazin, D.; Berryman, J. S.; Bruce, A. M.; Diget, C. Aa.; Iwasaki, H.; Lemasson, A.; McDaniel, S.; Napoli, D. R.; Ratkiewicz, A.; Scruton, L.; Shore, A.; Stroberg, R.; Tostevin, J. A.; Weisshaar, D.; Wimmer, K.; Winkler, R.

2013-08-01

126

Large 0/12 GMT Differences of US Vaisala RS80 Observations  

NASA Technical Reports Server (NTRS)

The daily differences between the temperatures and heights taken at 0 GMT and 12 GMT by Vaisala RS80 rawinsondes have been calculated. The observations were obtained during selected months from 1998 - 2002 over North America, Europe and Australia. The daily differences are defined by the formula, Delta T = Delta T(sub 0) - 0.5(T(sub -12) - T(sub +12)) where AT is the 0/12 GMT difference, T(sub 0) is the 0 GMT observation and T(sub -12) and T(sub +12) are the 12 GMT observations taken just prior and after the 0 GMT synoptic time. If T(sub +12) is missing then Delta T = T(sub 0) - T(sub -12). A similar expression is used if T(sub -12) is missing. Monthly averages of the increments at each station that launch RS80 rawinsondes are then calculated. The results show positive systematic differences in the stratosphere with values as high as 5 K and 150 m at 10 hPa over the central United States. The values remain generally positive and gradually decrease as the levels descend into the upper troposphere but are still significant. In addition, the maximum at each level is just westward of 90 W at the highest levels and just eastward in the troposphere with smaller values along both coasts. In Canada as well as in Europe and Australia the differences are much smaller with no systematic patterns similar to those that exist over the contiguous United States. Time-series plots of the temperatures and heights at select stations in the United States show that the observed values taken at 0 GMT are consistently higher than those at 12 GMT. Over Canada the differences become much less apparent and some cases non-existent. The observations were obtained through National Centers for Environmental Prediction (NCEP) but were checked with data from other sources to verify that no modifications were made other than those at the stations. Since the data from outside the the United States exhibit no large systematic differences, the preliminary conclusion is that the large differences are artificial and probably originate from the post-processing software at the observing stations.

Redder, Chris; Atlas, Robert (Technical Monitor)

2002-01-01

127

Large-scale psychological differences within China explained by rice versus wheat agriculture.  

PubMed

Cross-cultural psychologists have mostly contrasted East Asia with the West. However, this study shows that there are major psychological differences within China. We propose that a history of farming rice makes cultures more interdependent, whereas farming wheat makes cultures more independent, and these agricultural legacies continue to affect people in the modern world. We tested 1162 Han Chinese participants in six sites and found that rice-growing southern China is more interdependent and holistic-thinking than the wheat-growing north. To control for confounds like climate, we tested people from neighboring counties along the rice-wheat border and found differences that were just as large. We also find that modernization and pathogen prevalence theories do not fit the data. PMID:24812395

Talhelm, T; Zhang, X; Oishi, S; Shimin, C; Duan, D; Lan, X; Kitayama, S

2014-05-01

128

Large Variations In Medicare Payments For Surgery Highlight Savings Potential From Bundled Payment Programs  

PubMed Central

Payers are considering bundled payments for inpatient surgery, combining provider reimbursements into a single payment for the entire episode. We found that current Medicare episode payments for certain inpatient procedures varied by 49–130 percent across hospitals sorted into five payment groups. Intentional differences in payments attributable to such factors as geography or illness severity explained much of this variation. But after adjustment for these differences, per episode payments to the highest-cost hospitals were higher than those to the lowest-cost facilities by up to $2,549 for colectomy and $7,759 for back surgery. Postdischarge care accounted for a large proportion of the variation in payments, as did discretionary physician services, which may be driven in turn by variations in surgeons’ practice styles. Our study suggests that bundled payments could yield sizable savings for payers, although the effect on individual institutions will vary because hospitals that were relatively expensive for one procedure were often relatively inexpensive for others. More broadly, our data suggest that many hospitals have considerable room to improve their cost efficiency for inpatient surgery and should look for patterns of excess utilization, particularly among surgical specialties, other inpatient specialist consultations, and various types of postdischarge care.

Miller, David C.; Gust, Cathryn; Dimick, Justin B.; Birkmeyer, Nancy; Skinner, Jonathan; Birkmeyer, John D.

2014-01-01

129

Generation and homodyne detection of continuous-variable entangled optical beams with a large wavelength difference  

NASA Astrophysics Data System (ADS)

We present a scheme for generating and homodyne detecting of continuous-variable entanglement of bright optical beams with a large wavelength difference by utilizing an optical parametric oscillator (OPO) and an optical parametric amplifier (OPA) simultaneously. Entangled optical beams at 0.8 and 1.5 ?m are generated from the OPA; the seed beams injected in the OPA as well as the local oscillators at the two wavelengths needed for homodyne detection are provided by the OPO. The entangler is a ring resonator involving a second-order nonlinear crystal that is pumped from two opposite directions. In one direction the pump power is above the oscillation threshold and the optical nonlinear resonator operates as an OPO. In the other direction the pump power is below the threshold and it operates as a phase-sensitive frequency nondegenerate optical parametric amplifier. Our scheme combines the advantages of both OPO and OPA quantum optical devices and opens another avenue for preparation and homodyne detection of high quality bright entangled light with a large wavelength difference.

Guo, Xiaomin; Xie, Changde; Li, Yongmin

2011-08-01

130

Generation and homodyne detection of continuous-variable entangled optical beams with a large wavelength difference  

SciTech Connect

We present a scheme for generating and homodyne detecting of continuous-variable entanglement of bright optical beams with a large wavelength difference by utilizing an optical parametric oscillator (OPO) and an optical parametric amplifier (OPA) simultaneously. Entangled optical beams at 0.8 and 1.5 {mu}m are generated from the OPA; the seed beams injected in the OPA as well as the local oscillators at the two wavelengths needed for homodyne detection are provided by the OPO. The entangler is a ring resonator involving a second-order nonlinear crystal that is pumped from two opposite directions. In one direction the pump power is above the oscillation threshold and the optical nonlinear resonator operates as an OPO. In the other direction the pump power is below the threshold and it operates as a phase-sensitive frequency nondegenerate optical parametric amplifier. Our scheme combines the advantages of both OPO and OPA quantum optical devices and opens another avenue for preparation and homodyne detection of high quality bright entangled light with a large wavelength difference.

Guo Xiaomin; Xie Changde; Li Yongmin [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China)

2011-08-15

131

Time difference of arrival to blast localization of potential chemical/biological event on the move  

NASA Astrophysics Data System (ADS)

Integrating a sensor suite with ability to discriminate potential Chemical/Biological (CB) events from high-explosive (HE) events employing a standalone acoustic sensor with a Time Difference of Arrival (TDOA) algorithm we developed a cueing mechanism for more power intensive and range limited sensing techniques. Enabling the event detection algorithm to locate to a blast event using TDOA we then provide further information of the event as either Launch/Impact and if CB/HE. The added information is provided to a range limited chemical sensing system that exploits spectroscopy to determine the contents of the chemical event. The main innovation within this sensor suite is the system will provide this information on the move while the chemical sensor will have adequate time to determine the contents of the event from a safe stand-off distance. The CB/HE discrimination algorithm exploits acoustic sensors to provide early detection and identification of CB attacks. Distinct characteristics arise within the different airburst signatures because HE warheads emphasize concussive and shrapnel effects, while CB warheads are designed to disperse their contents over large areas, therefore employing a slower burning, less intense explosive to mix and spread their contents. Differences characterized by variations in the corresponding peak pressure and rise time of the blast, differences in the ratio of positive pressure amplitude to the negative amplitude, and variations in the overall duration of the resulting waveform. The discrete wavelet transform (DWT) is used to extract the predominant components of these characteristics from air burst signatures at ranges exceeding 3km. Highly reliable discrimination is achieved with a feed-forward neural network classifier trained on a feature space derived from the distribution of wavelet coefficients and higher frequency details found within different levels of the multiresolution decomposition. The development of an adaptive noise floor to provide early event detection assists in minimizing the false alarm rate and increasing the confidence whether the event is blast event or back ground noise. The integration of these algorithms with the TDOA algorithm provides a complex suite of algorithms that can give early warning detection and highly reliable look direction from a great stand-off distance for a moving vehicle to determine if a candidate blast event is CB and if CB what is the composition of the resulting cloud.

Morcos, Amir; Desai, Sachi; Peltzer, Brian; Hohil, Myron E.

2007-10-01

132

Age-Dependent Telomere Attrition as a Potential Indicator of Racial Differences in Renal Growth Patterns  

Microsoft Academic Search

Background: Racial differences in the predilection to salt sensitivity may arise from different renal growth patterns. To test this idea, we monitored age-dependent telomere attrition rate, reflecting largely the replicative history of somatic cells, in the outer renal cortex and the inner renal medulla of African Americans and Caucasians. Methods: Telomere length, determined by the mean length of the terminal

L. Tchakmakjian; J. P. Gardner; P. D. Wilson; M. Kimura; J. Skurnick; H. R. Zielke; A. Aviv

2004-01-01

133

Sex Differences on "g" and Non-"g" Intellectual Performance Reveal Potential Sources of STEM Discrepancies  

ERIC Educational Resources Information Center

The analysis of sex differences in cognitive abilities is largely confusing because these differences are masked by the pervasive influence of the general factor of intelligence (g). In this study a battery of five reasoning tests (abstract [AR], numerical [NR], verbal [VR], mechanical [MR], and spatial [SR]) was completed by a sample of 3233…

Lemos, Gina C.; Abad, Francisco J.; Almeida, Leandro S.; Colom, Roberto

2013-01-01

134

How Teachers and Schools Contribute to Racial Differences in the Realization of Academic Potential  

ERIC Educational Resources Information Center

Background/Context: The fulfillment of academic potential is an underdeveloped area of inquiry as it relates to explaining racial differences in academic outcomes. Examining this issue is important for addressing not only differences in the typical outcomes for African American and White students but also the severe underrepresentation of African…

Wildhagen, Tina

2012-01-01

135

Large pi-aromatic molecules as potential sensitizers for highly efficient dye-sensitized solar cells.  

PubMed

Recently, dye-sensitized solar cells have attracted much attention relevant to global environmental issues. Thus far, ruthenium(II) bipyridyl complexes have proven to be the most efficient TiO(2) sensitizers in dye-sensitized solar cells. However, a gradual increment in the highest power conversion efficiency has been recognized in the past decade. More importantly, considering that ruthenium is a rare metal, novel dyes without metal or using inexpensive metal are desirable for highly efficient dye-sensitized solar cells. Large pi-aromatic molecules, such as porphyrins, phthalocyanines, and perylenes, are important classes of potential sensitizers for highly efficient dye-sensitized solar cells, owing to their photostability and high light-harvesting capabilities that can allow applications in thinner, low-cost dye-sensitized solar cells. Porphyrins possess an intense Soret band at 400 nm and moderate Q bands at 600 nm. Nevertheless, the poor light-harvesting properties relative to the ruthenium complexes have limited the cell performance of porphyrin-sensitized TiO(2) cells. Elongation of the pi conjugation and loss of symmetry in porphyrins cause broadening and a red shift of the absorption bands together with an increasing intensity of the Q bands relative to that of the Soret band. On the basis of the strategy, the cell performance of porphyrin-sensitized solar cells has been improved intensively by the enhanced light absorption. Actually, some push-pull-type porphyrins have disclosed a remarkably high power conversion efficiency (6-7%) that was close to that of the ruthenium complexes. Phthalocyanines exhibit strong absorption around 300 and 700 nm and redox features that are similar to porphyrins. Moreover, phthalocyanines are transparent over a large region of the visible spectrum, thereby enabling the possibility of using them as "photovoltaic windows". However, the cell performance was poor, owing to strong aggregation and lack of directionality in the excited state. Novel unsymmetrical zinc phthalocyanine sensitizers with "push" and "pull" groups have made it possible to reduce the aggregation on a TiO(2) surface, tune the level of the excited state, and strengthen the electronic coupling between the phthalocyanine core and the TiO(2) surface. As a result, the power conversion efficiency of up to 3.5% has been achieved. Perylenes are well-known as chemically, thermally, and photophysically stable dyes and have been used in various optical devices and applications. Nevertheless, the power conversion efficiency remained low compared to other organic dyes. The origin of such limited cell performance is the poor electron-donating abilities of the perylenes, which makes it difficult to inject electrons from the excited singlet state of the perylenes to the conduction band of the TiO(2) electrode efficiently. Strongly electron-donating perylene carboxylic acid derivatives with amine substituents at their perylene core have allowed us to increase the power conversion efficiency of up to approximately 7% in perylene-sensitized solar cells. The efficiency of large pi-aromatic molecule-sensitized solar cells could be improved significantly if the dyes with larger red and near-infrared absorption could be developed. PMID:19408942

Imahori, Hiroshi; Umeyama, Tomokazu; Ito, Seigo

2009-11-17

136

Estimating Large-Customer Demand Response Market Potential:Integrating Price and Customer Behavior  

Microsoft Academic Search

ABSTRACT=Demand response (DR) is increasingly recognized asan essential ingredient to well-functioning electricity markets. DRmarket potential studies can answer questions about the amount of DRavailable in a given area, from which market segments. Several recent DRmarket potential studies have been conducted, most adapting techniquesused to estimate energy-efficiency (EE) potential. In this scoping study,we: reviewed and categorized seven recent DR market potential

Charles Goldman; Nicole Hopper; Ranjit Bharvirkar; Bernie Neenan; Peter Cappers

2007-01-01

137

A Methodology for Estimating Large-Customer Demand Response MarketPotential  

Microsoft Academic Search

Demand response (DR) is increasingly recognized as an essential ingredient to well-functioning electricity markets. DR market potential studies can answer questions about the amount of DR available in a given area and from which market segments. Several recent DR market potential studies have been conducted, most adapting techniques used to estimate energy-efficiency (EE) potential. In this scoping study, we: reviewed

Charles Goldman; Nicole Hopper; Ranjit Bharvirkar; Bernie Neenan; Peter Cappers

2007-01-01

138

A multigrid method for natural convective heat transfer with large temperature differences  

NASA Astrophysics Data System (ADS)

Steady-state two-dimensional solutions to the full compressible Navier-Stokes equations are computed for laminar convective motion of a gas in a square cavity with large horizontal temperature differences. Results for air are presented. The ideal-gas law is used and viscosity is given by Sutherland's law. An accurate low-Mach number solver is developed. Hereby an explicit third-order discretization for the convective part and a line-implicit central discretization for the acoustic part and for the diffusive part are used. The semi-implicit line method is formulated in multistage form. Multigrid is used as acceleration technique. A convergence behaviour is obtained which is independent of grid size, grid aspect ratio, Mach number and Rayleigh number. Grid converged results are shown for Rayleigh numbers between 102 and 107.

Vierendeels, Jan; Merci, Bart; Dick, Erik

2004-07-01

139

Large differences in catch per unit of effort between two minnow trap models  

PubMed Central

Background Little is known about variation in catch per unit of effort (CPUE) in stickleback fisheries, or the factors explaining this variation. We investigated how nine-spined stickleback (Pungitius pungitius) CPUE was influenced by trap model by comparing the CPUEs of two very similar minnow trap models fished side-by-side in a paired experimental design. Results The galvanized trap type (mean CPUE?=?1.31 fish h–1) out-fished the black trap type (mean CPUE?=?0.20 fish h–1) consistently, and yielded on average 81% more fish. Conclusions The results demonstrate that small differences in trap appearance can have large impacts on CPUE. This has implications for studies designed to investigate abundance and occurrence of fish using minnow traps.

2013-01-01

140

Anaerobic treatability and biogas production potential studies of different agro-industrial wastewaters in Turkey  

Microsoft Academic Search

The anaerobic treatability and methane generation potential of the wastewaters of the three important agro-industries in Turkey, namely, cheese-making, poultry breeding and the olive-oil mill industries were studied. Biochemical methane potential (BMP) experiments were conducted for different initial chemical oxygen demand (COD) concentrations. The results indicate that anaerobic treatment was possible for all the wastewaters studied and the biogas produced

Göksel N. Demirer; Metin Duran; Engin Güven; Örgen Ugurlu; Ulas Tezel; Tuba H. Ergüder

2000-01-01

141

Mapping membrane potential differences and dye-coupling in internodal tissues of tomato ( Solanum lycopersicum L.)  

Microsoft Academic Search

Symplastic continuity in internodal tissues of tomato was investigated by electrophysiological and micro-injection techniques. Recordings of potential differences (pd) were combined with iontophoretic injection of 5,6-carboxyfluorescein (CF) and Lucifer Yellow CH (LYCH). Mapping of pds and dye-coupling respectively labeled the potential sites of major solute uptake and the spatial differentiation in symplast permeability. The cells of the central pith had

C. Schoot; A. J. E. Bel

1990-01-01

142

In vitro evaluation of UV opacity potential of Aloe vera L. gel from different germplasms  

Microsoft Academic Search

In this study, lyophilized crude and methanolic extracts of aloe gel from different germplasms (S24, RM, TN, OR, and RJN)\\u000a of Aloe vera L. were tested for their ultraviolet (UV) opacity potential. UV absorption profiles, sun protection factor (SPF), and percentage\\u000a blocking of UVA and UVB were considered to test UV opacity potential. Both the extracts showed UV absorption and

M. Shyam Kumar; P. K. Datta; S. Dutta Gupta

2009-01-01

143

Zeta potential determination of polymeric materials using two differently designed measuring cells of an electrokinetic analyzer.  

PubMed

The so-called zeta potential can be determined through electrokinetic measurements and indicates the status regarding surface charges along the interface between solids and liquids. Surface charge gives us information about the condition, quality, and characteristics of a macroscopic surface in the polar medium. In our study the zeta potential was determined using a "SurPASS" electrokinetic analyzer based on the streaming current and streaming potential measurements. The aim of the research was to compare the results of two differently designed measuring cells ("Adjustable Gap Cell" and "Clamping Cell") but operating on the same principle. In order to investigate this problem, the zeta potential was determined for the three polymeric materials: poly(ethylene terephthalate) foil, thin-film polyamide composite membranes for nanofiltration and reverse osmosis. The results obtained with "Clamping Cell" versus "Adjustable Gap Cell" showed differences in zeta potential, where the "Adjustable Gap Cell" gave more reproducible results. One reason for this behaviour could be the different geometries of the streaming channels. A more likely reason is the design of the "Clamping Cell", that requires a sample size larger than necessary for zeta potential determination. PMID:24061819

Bukšek, Hermina; Luxbacher, Thomas; Petrini?, Irena

2010-09-01

144

Effect of Annealing Process On ZnO Nanorod Prepared At Different Potentials Using Electrodeposition Technique  

NASA Astrophysics Data System (ADS)

This paper carried out to investigate the different potentials due to 500° C annealing temperatures. The potentials range from -1.0 to -1.4 V were deposited by electrochemical deposition technique that consist three electrode used. Cyclic voltammogram graph was studies to determine the potentials for deposit the ZnO and chronoamprometry graph for investigate current-time during deposition process occurred. The surface morphology of ZnO film was observed by using field emission scanning electron microscopy (FESEM). It shown the images for all potentials after annealing in oxygen gas and diameter of ZnO sizes film was increasing when the potential was smaller. The roughness of ZnO films were investigate by measuring using surface profiler and the result shown that less roughness at high potentials. XRD patterns of ZnO films crystallites at different potentials and at -1.2 V have high peak intense with (002) plane as preferential axis structures in annealing process. The PL spectra reveal the ZnO crystal has UV emission band around 380 nm. These results will provide new technique to produce nanorod of ZnO film and also can fabricate for optoelectronic devices applications.

Rodzi, Ana Syahidah; Mamat, Mohamad Hafiz; Zahidi, Musa Mohamed; Mohd, Yusairie; Berhan, Mohamad Nor; Rusop, Mohamad

2011-05-01

145

Placental mesenchymal stem cells of fetal and maternal origins demonstrate different therapeutic potentials  

PubMed Central

Introduction Therapeutic potentials of mesenchymal stem cells (MSCs) from different sources have been evaluated in pre-clinical and clinical settings. Although MSCs from different sources share MSC-specific characteristics and functions, inconsistent or controversial results of pre-clinical and clinical applications of such cells are frequently reported. This may be partially due to the fact that MSCs isolated from different origins may differentially express some functions not typical for MSCs, and hence have different therapeutic potentials. The aim of this study is to investigate the differences in human placental MSCs (P-MSCs) of fetal and maternal origins in the aspects of clinical importance. Methods P-MSCs of fetal and maternal origins isolated from normal term placentas were characterized for their typical phenotype as well as their expression of receptors and growth factors of clinic interests. P-MSCs that preferentially express hepatocyte growth factor (HGF) and CD200 were evaluated for their therapeutic potentials in models of angiogenesis and allogeneic skin transplantation, in comparison with their HGF and CD200 negative partners. Results Although all P-MSCs express typical MSC phenotype, fetal but not maternal P-MSCs express high levels of CD200 and HGF. Compared with HGF and CD200 negative P-MSCs, HGF and CD200 positive cells demonstrated significantly high potentials in promoting angiogenesis in vitro and increasing immunosuppressive function in vivo. These therapeutic potentials were at least in part due to their differences in HGF and CD200 expression, respectively. Conclusions We conclude that MSC origins may have significant impact on the therapeutic potentials of such cells, and should be taken into consideration in clinical applications.

2014-01-01

146

In vitro Antioxidant Potential of Different Parts of Oroxylum indicum: A Comparative Study.  

PubMed

The present study evaluated the in vitro antioxidant potential of different parts of Oroxylum indicum. 2,2-diphelyl 1-picrylhydrazyl (DPPH), nitric oxide, superoxide anion and hydroxyl radical scavenging potential and reductive ability assay of methanol extract of different parts i.e. root, root bark, stem, stem bark, leaves and fruits were performed. Leaves and bark extracts exhibits highest free radical scavenging activity than bark, stem and fruit extract. Leaves extract showed maximum reductive ability and found to contain maximum amount of polyphenolic compounds. The highest free radical activity may be due to presence of polyphenolic compounds. PMID:20838540

Mishra, S L; Sinhamahapatra, P K; Nayak, A; Das, R; Sannigrahi, S

2010-03-01

147

In vitro Antioxidant Potential of Different Parts of Oroxylum indicum: A Comparative Study  

PubMed Central

The present study evaluated the in vitro antioxidant potential of different parts of Oroxylum indicum. 2,2-diphelyl 1-picrylhydrazyl (DPPH), nitric oxide, superoxide anion and hydroxyl radical scavenging potential and reductive ability assay of methanol extract of different parts i.e. root, root bark, stem, stem bark, leaves and fruits were performed. Leaves and bark extracts exhibits highest free radical scavenging activity than bark, stem and fruit extract. Leaves extract showed maximum reductive ability and found to contain maximum amount of polyphenolic compounds. The highest free radical activity may be due to presence of polyphenolic compounds.

Mishra, S. L.; Sinhamahapatra, P. K.; Nayak, A.; Das, R.; Sannigrahi, S.

2010-01-01

148

The Effect of Large Ability Differences on Type I Error and Power Rates Using SIBTEST and TESTGRAF DIF Detection Procedures.  

ERIC Educational Resources Information Center

A simulation study was conducted to examine the effect of large ability differences using two differential item functioning (DIF) detection procedures, SIBTEST and TESTGRAF. DIF items are hard to identify when group ability differences are large (A. Gotzmann, C. Vandenberghe, and M. Gierl, 2000; R. Hambleton and H. Rogers, 1989). This problem was…

Gotzmann, Andrea J.

149

Differences between local and remote interannual climate forcings acting on the Brazilian Large Marine Ecosystems  

NASA Astrophysics Data System (ADS)

Large Marine Ecosystems (LMEs) are units defined based on the differences in hydrographic regimes, bathymetry, productivity and trophycally dependent populations and were established for assessment and management of marine resources and control of degradation of the coastal areas around the world. Three LME are located in the Brazilian domain, the North, East and South LMEs. In this study the influence of interannual climate variations on Brazilian LMEs are investigated. The South Atlantic is subject to local climatic modes, such as the Interhemispheric Sea Surface Temperature (SST) gradient, represented by the Tropical South Atlantic (TSA) and Tropical North Atlantic (TNA) indices and Antarctic Oscillation mode, represented by Antarctic Oscillation (AAO) index. The remote forcings considered in this work are El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). Total and partial correlation (95% significance) analyses of climate indices versus SST, wind stress, sea level pressure (SLP) and outgoing long wave radiation (OLR) were calculated. The data series used were detrended and filtered to retain the interannual (2 to 7 years) variability. Correlations were carried out separately for the cold (1948/1976) and warm PDO phase (1977/2008). Results point to higher correlations between wind stress anomaly, SLP anomaly, SST anomaly (SSTA) and the Niño 3 index for a large part of the South Atlantic during the PDO warm phase than in the cold phase. The North Brazil LME region is strongly influenced by El Niño, with a maximum positive correlation between SSTA and Niño 3 found with 7 months lag and a positive correlation between this index and wind stress with a maximum time lag of 2 months. The East LME unit appears to be influenced in a very different way in its southern and northern portion, suggesting that management actions for the adaptation or mitigation for possible climate variability changes needs to consider this difference. The AAO is negatively correlated with SSTA between 20° and 35°S, being the sole climate index showing significant correlations in this area. Another aspect observed is that in the North region of the basin the correlation between AAO and SSTA seems to be intensified by the TSA interaction. The next step of this work will be to use the Regional Ocean Modeling System (ROMS) with a biogeochemical component to evaluate the impacts of climate variability on the LMEs biological productivity.

Soares, H. C.; Gherardi, D. F.; Pezzi, L. P.; Kayano, M. T.

2013-05-01

150

Prediction model of potential hepatocarcinogenicity of rat hepatocarcinogens using a large-scale toxicogenomics database  

SciTech Connect

The present study was performed to develop a robust gene-based prediction model for early assessment of potential hepatocarcinogenicity of chemicals in rats by using our toxicogenomics database, TG-GATEs (Genomics-Assisted Toxicity Evaluation System developed by the Toxicogenomics Project in Japan). The positive training set consisted of high- or middle-dose groups that received 6 different non-genotoxic hepatocarcinogens during a 28-day period. The negative training set consisted of high- or middle-dose groups of 54 non-carcinogens. Support vector machine combined with wrapper-type gene selection algorithms was used for modeling. Consequently, our best classifier yielded prediction accuracies for hepatocarcinogenicity of 99% sensitivity and 97% specificity in the training data set, and false positive prediction was almost completely eliminated. Pathway analysis of feature genes revealed that the mitogen-activated protein kinase p38- and phosphatidylinositol-3-kinase-centered interactome and the v-myc myelocytomatosis viral oncogene homolog-centered interactome were the 2 most significant networks. The usefulness and robustness of our predictor were further confirmed in an independent validation data set obtained from the public database. Interestingly, similar positive predictions were obtained in several genotoxic hepatocarcinogens as well as non-genotoxic hepatocarcinogens. These results indicate that the expression profiles of our newly selected candidate biomarker genes might be common characteristics in the early stage of carcinogenesis for both genotoxic and non-genotoxic carcinogens in the rat liver. Our toxicogenomic model might be useful for the prospective screening of hepatocarcinogenicity of compounds and prioritization of compounds for carcinogenicity testing. - Highlights: >We developed a toxicogenomic model to predict hepatocarcinogenicity of chemicals. >The optimized model consisting of 9 probes had 99% sensitivity and 97% specificity. >This model enables us to detect genotoxic as well as non-genotoxic hepatocarcinogens.

Uehara, Takeki, E-mail: takeki.uehara@shionogi.co.jp [Drug Developmental Research Laboratories, Shionogi and Co., Ltd., 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825 (Japan); Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085 (Japan); Minowa, Yohsuke; Morikawa, Yuji [Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085 (Japan); Kondo, Chiaki; Maruyama, Toshiyuki; Kato, Ikuo [Drug Developmental Research Laboratories, Shionogi and Co., Ltd., 3-1-1 Futaba-cho, Toyonaka, Osaka 561-0825 (Japan); Nakatsu, Noriyuki; Igarashi, Yoshinobu; Ono, Atsushi [Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085 (Japan); Hayashi, Hitomi [Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Harumi-cho, Fuchu, Tokyo 183-8509 (Japan); Pathogenetic Veterinary Science, United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193 Gifu (Japan); Mitsumori, Kunitoshi [Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Harumi-cho, Fuchu, Tokyo 183-8509 (Japan); Yamada, Hiroshi [Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085 (Japan); Ohno, Yasuo [National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501 (Japan); Urushidani, Tetsuro [Toxicogenomics Informatics Project, National Institute of Biomedical Innovation, 7-6-8 Asagi, Ibaraki, Osaka 567-0085 (Japan); Department of Pathophysiology, Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts, Kodo, Kyotanabe, Kyoto 610-0395 (Japan)

2011-09-15

151

Ca(2+)-dependent large conductance K(+) currents in thalamocortical relay neurons of different rat strains.  

PubMed

Mutations in genes coding for Ca(2+) channels were found in patients with childhood absence epilepsy (CAE) indicating a contribution of Ca(2+)-dependent mechanisms to the generation of spike-wave discharges (SWD) in humans. Since the involvement of Ca(2+) signals remains unclear, the aim of the present study was to elucidate the function of a Ca(2+)-dependent K(+) channel (BKCa) under physiological conditions and in the pathophysiological state of CAE. The activation of BKCa channels is dependent on both voltage and intracellular Ca(2+) concentrations. Moreover, these channels exhibit an outstandingly high level of regulatory heterogeneity that builds the basis for the influence of BKCa channels on different aspects of neuronal activity. Here, we analyse the contribution of BKCa channels to firing of thalamocortical relay neurons, and we test the hypothesis that BKCa channel activity affects the phenotype of a genetic rat model of CAE. We found that the activation of the ?2-adrenergic receptor/protein kinase A pathway resulted in BKCa channel inhibition. Furthermore, BKCa channels affect the number of action potentials fired in a burst and produced spike frequency adaptation during tonic activity. The latter result was confirmed by a computer modelling approach. We demonstrate that the ?2-adrenergic inhibition of BKCa channels prevents spike frequency adaptation and, thus, might significantly support the tonic firing mode of thalamocortical relay neurons. In addition, we show that BKCa channel functioning differs in epileptic WAG/Rij and thereby likely contributes to highly synchronised, epileptic network activity. PMID:23207578

Ehling, Petra; Cerina, Manuela; Meuth, Patrick; Kanyshkova, Tatyana; Bista, Pawan; Coulon, Philippe; Meuth, Sven G; Pape, Hans-Christian; Budde, Thomas

2013-04-01

152

Modelling nitrogen retention in floodplains with different degrees of degradation for three large rivers in Germany.  

PubMed

Floodplains perform a variety of ecosystem functions and services - more than many other ecosystems. One of these ecosystem services is the reduction in nitrogen (N) loads and a subsequent improvement to the water quality. Since diffuse and also point nitrogen sources continue to cause a variety of problems in rivers and floodplains, inundated floodplains could act as net sinks for N and are therefore of great importance throughout Germany and Europe. This study analyses the effects of riparian floodplains on N-retention on the landscape scale for three large river systems with different degrees of degradation. Two approaches, differing in terms of the complexity of their respective input data and methods, were applied under wet and dry conditions. Whereas the proxy-based approach considers proxy values for N-retention, the model-based approach accounts for event-driven dynamic input data such as the extent of the inundated floodplain and incoming loads. Comparing the results of the two approaches it can be observed that floodplains of the near-natural river can retain up to 4% of the river load under wet conditions. During such conditions N-retention in floodplains is similar to that of rivers. For the two other floodplains, the results of the two approaches were quite different, showing lower N-retention capacities. However, for these floodplains as well, both approaches are suitable for calculating measurable N-retention rates, which is an important result because it also suggests that even degraded floodplains still preserve this particular ecosystem function and therefore still contribute to improving the quality of river water. PMID:23545402

Natho, S; Venohr, M; Henle, K; Schulz-Zunkel, C

2013-06-15

153

Engagement of large-scale networks is related to individual differences in inhibitory control  

PubMed Central

Understanding which brain regions regulate the execution, and suppression, of goal-directed behavior has implications for a number of areas of research. In particular, understanding which brain regions engaged during tasks requiring the execution and inhibition of a motor response provides insight into the mechanisms underlying individual differences in response inhibition ability. However, neuroimaging studies examing the relation between activation and stopping have been inconsistent regarding the direction of the relationship, and also regarding the anatomical location of regions that correlate with behavior. These limitations likely arise from the relatively low power of vox-elwise correlations with small sample sizes. Here, we pooled data over five separate fMRI studies of the Stop-signal task in order to obtain a sufficiently large sample size to robustly detect brain/behavior correlations. In addition, rather than performing mass univariate correlation analysis across all voxels, we increased statistical power by reducing the dimensionality of the data set using independent components analysis and then examined correlations between behavior and the resulting component scores. We found that components reflecting activity in regions thought to be involved in stopping were associated with better stopping ability, while activity in a default-mode network was associated with poorer stopping ability across individuals. These results clearly show a relationship between individual differences in stopping ability in specific activated networks, including regions known to be critical for the behavior. The results also highlight the usefulness of using dimensionality reduction to increase the power to detect brain/behavior correlations in individual differences research.

Congdon, Eliza; Mumford, Jeanette A.; Cohen, Jessica R.; Galvan, Adriana; Aron, Adam R.; Xue, Gui; Miller, Eric; Poldrack, Russell A.

2010-01-01

154

Tetraploid and hexaploid wheat varieties reveal large differences in expression of alpha-gliadins from homoeologous Gli-2 loci  

PubMed Central

Background ?-gliadins form a multigene protein family encoded by multiple ?-gliadin (Gli-2) genes at three genomic loci, Gli-A2, Gli-B2 and Gli-D2, respectively located on the homoeologous wheat chromosomes 6AS, 6BS, and 6DS. These proteins contain a number of important celiac disease (CD)-immunogenic domains. The ?-gliadins expressed from the Gli-B2 locus harbour fewer conserved CD-epitopes than those from Gli-A2, whereas the Gli-D2 gliadins have the highest CD-immunogenic potential. In order to detect differences in the highly CD-immunogenic ?-gliadin fraction we determined the relative expression level from the homoeologous Gli-2 loci in various tetraploid and hexaploid wheat genotypes by using a quantitative pyrosequencing method and by analyzing expressed sequence tag (EST) sequences. Results We detected large differences in relative expression levels of ?-gliadin genes from the three homoeologous loci among wheat genotypes, both as relative numbers of expressed sequence tag (EST) sequences from specific varieties and when using a quantitative pyrosequencing assay specific for Gli-A2 genes. The relative Gli-A2 expression level in a tetraploid durum wheat cultivar ('Probstdorfer Pandur') was 41%. In genotypes derived from landraces, the Gli-A2 frequency varied between 12% and 58%. In some advanced hexaploid bread wheat cultivars the genes from locus Gli-B2 were hardly expressed (e.g., less than 5% in 'Lavett') but in others they made up more than 40% (e.g., in 'Baldus'). Conclusion Here, we have shown that large differences exist in relative expression levels of ?-gliadins from the homoeologous Gli-2 loci among wheat genotypes. Since the homoelogous genes differ in the amount of conserved CD-epitopes, screening for differential expression from the homoeologous Gli-2 loci can be employed for the pre-selection of wheat varieties in the search for varieties with very low CD-immunogenic potential. Pyrosequencing is a method that can be employed for such a 'gene family-specific quantitative transcriptome profiling'.

Salentijn, Elma MJ; Goryunova, Svetlana V; Bas, Noor; van der Meer, Ingrid M; van den Broeck, Hetty C; Bastien, Thomas; Gilissen, Luud JWJ; Smulders, Marinus JM

2009-01-01

155

Structure of different within-plate magmatic system of large igneous provinces  

NASA Astrophysics Data System (ADS)

It is generally accepted that formation of continental large igneous provinces (LIPs) is linked with ascending of mantle superplumes. However, it is not clear yet why and how magmatic systems appeared and functionated. It is known that LIPs are formed by numerous magmatic centers, which imply existence of individual magmatic systems beneath them. Such a situation can be explained by presence of protuberances (local plumes) on the surface of extended superplume heads, where processes of adiabatic melting occurred give rise to formation of magmatic systems. Newly-formed melts on their way to the surface pass through complicate system of conduits and transitional magma chambers, where they were undergone by different processes of crystallizing differentiation, mixing, assimilation of wall-rocks, etc. According to data available, three major levels of transitional magmatic chambers, linked by systems of feeder conduits (dikes), occurred within the crust. Each of them is responsible for transformation of a primary melt in different extent: The lowest level with the largest chambers, located along boundary between upper margin of the plume head and incumbent rigid lithosphere; they are responsible for the underplating phenomenon. Processes of contamination mantle-derived magmas by crustal material can play essential role here, especially in the late Archean and early Paleoproterozoic when they led to appearance of specific mantle-crustal magmas of siliceous high-Mg series (SHMS), which formed large igneous provinces with numerous mafic-iltramafic layered intrusions (Sharkov, Bogina, 2006). It suggests that formation of this series was linked with "floating up" of chambers (batches) of high-temperature ultramafic magmas through the upper part of lithospheric mantle and mafic lower crust by zone refinement mechanism, i.e. by melting material of the chamber's roof and crystallization at their bottoms. As a result, the primary melt gradually enriched in crustal material; portions of such series of melts periodically arrived into hardening transitional magma chambers of the middle level. Very likely that such structure of magmatic systems was typical also for the earliest Moon's magnesian suite magmatism, where such type layered mafic-ultramafic intrusions was found (Snyder et al., 1995). (2) Processes at the middle level are easy to understand on example of large layered mafic-ultramafic intrusions which are represent hardened transition magma chambers. Crystallizing differentiation as well as mixing of periodically arrived into hardening intrusive chambers fresh portions of magmas with evolved melts in it occurred here. Specific type of transitional magma chambers are represented by huge bimodal anorthosite-rapakivi granite complexes (ARGCs), typical for the Mesoproterozoic. They were formed under conditions of unusually thick (70-80 km at the moment) continental crust. Geological, geochemical and isotope data evidence that melting in the mantle and silicic crust occurred here simultaneously above local mantle plumes. It suggests that melting of the crust's material occurred above sill-like intrusions of basaltic melt which were led to appearance of large magma chambers, where mafic and sialic melts coexisted; such chambers represented now as ARGCs. By contrast to continental crust, under conditions of thin oceanic crust processes at the low and middle levels of magmatic systems are united, and layered mafic-ultramafic intrusions occurred directly between the ultramafic mantle and rocks of the upper crust, play role of the lower oceanic crust, how it is easily to observe on example of ophiolite associations. (3) The shallow level - subvolcanic chambers (usually sills), from which melts arrive to the surface, forming individual volcanoes and lava plateaus. Processes of contamination of wall rocks and crystallizing differentiation are very limited here due to small size of bodies and, accordingly, low heat keeping and quickly hardening. So, primary magmatic melt can reach the surface very rare; as a rule, it had undergone

Sharkov, E.

2009-04-01

156

Parametric Evaluation of Large-Scale High-Temperature Electrolysis Hydrogen Production Using Different Advanced Nuclear Reactor Heat Sources  

SciTech Connect

High Temperature Electrolysis (HTE), when coupled to an advanced nuclear reactor capable of operating at reactor outlet temperatures of 800 °C to 950 °C, has the potential to efficiently produce the large quantities of hydrogen needed to meet future energy and transportation needs. To evaluate the potential benefits of nuclear-driven hydrogen production, the UniSim process analysis software was used to evaluate different reactor concepts coupled to a reference HTE process design concept. The reference HTE concept included an Intermediate Heat Exchanger and intermediate helium loop to separate the reactor primary system from the HTE process loops and additional heat exchangers to transfer reactor heat from the intermediate loop to the HTE process loops. The two process loops consisted of the water/steam loop feeding the cathode side of a HTE electrolysis stack, and the sweep gas loop used to remove oxygen from the anode side. The UniSim model of the process loops included pumps to circulate the working fluids and heat exchangers to recover heat from the oxygen and hydrogen product streams to improve the overall hydrogen production efficiencies. The reference HTE process loop model was coupled to separate UniSim models developed for three different advanced reactor concepts (a high-temperature helium cooled reactor concept and two different supercritical CO2 reactor concepts). Sensitivity studies were then performed to evaluate the affect of reactor outlet temperature on the power cycle efficiency and overall hydrogen production efficiency for each of the reactor power cycles. The results of these sensitivity studies showed that overall power cycle and hydrogen production efficiencies increased with reactor outlet temperature, but the power cycles producing the highest efficiencies varied depending on the temperature range considered.

Edwin A. Harvego; Michael G. McKellar; James E. O'Brien; J. Stephen Herring

2009-09-01

157

Antioxidant Potential of Crude Extract and Different Fractions of Enhydra fluctuans Lour  

PubMed Central

The antioxidant potential of crude methanol extract (CE) as well as chloroform (CF), ethyl acetate (EF) and n-butanol (NF) soluble fractions of Enhydra fluctuans Lour, which is widely used in indigenous system of medicine for different purposes, were studied. The antioxidant potential of extract/different fractions were evaluated using different in vitro antioxidant models. In addition, total amount of polyphenolics compounds, DPPH (1,1-diphenyl-2-picryl hydrazyl) radical, nitric oxide, superoxide anion, hydroxyl radical scavenging activities and reductive power of crude extracted its different fractions were determined. It was found that ethyl acetate fraction have maximum amount of polyphenolics compounds (179.7 ± 18.23 ?g / mg pyrocatechol equivalent). This fraction was found more effective than crude extract and other fractions in all the above mentioned assays.

Sannigrahi, Santanu; Kanti Mazuder, Upal; Kumar Pal, Dilip; Parida, Sambit; Jain, Sourabh

2010-01-01

158

Comparison of the solar energy utilisation potential of different urban environments  

Microsoft Academic Search

Besides a more efficient energy use, large scale application of solar energy technologies in the urban context will be necessary in the upcoming decades to achieve a drastic reduction of greenhouse gas emissions in the biosphere. Two different urban sites, representative of two of the largest Swiss cities (Basel and Geneva), were examined under this aspect in order to assess

M Montavon; J-L Scartezzini; R Compagnon

159

A conservative implicit finite difference algorithm for the unsteady transonic full potential equation  

NASA Technical Reports Server (NTRS)

An implicit finite difference procedure is developed to solve the unsteady full potential equation in conservation law form. Computational efficiency is maintained by use of approximate factorization techniques. The numerical algorithm is first order in time and second order in space. A circulation model and difference equations are developed for lifting airfoils in unsteady flow; however, thin airfoil body boundary conditions have been used with stretching functions to simplify the development of the numerical algorithm.

Steger, J. L.; Caradonna, F. X.

1980-01-01

160

The Information Management Tool (IMT) of Gaia DPAC and its potential as tool for large scale software development projects  

NASA Astrophysics Data System (ADS)

The Gaia Data Processing and Analysis Consortium (DPAC) is developing the required software to handle and process the data collected during ESA’s Gaia astronomy mission. DPAC consist of more than 400 scientists and engineers developing several dozens of large software packages. Such a large software development project requires adequate progress monitoring techniques. DPAC has developed IMT as a semi automated monitoring tool. In this paper we will describe the IMT system, the results it provides, and the experiences in view of usage withing the DPAC management process. Also the potential usage of IMT in other large scientific projects is discussed.

Comoretto, G.; Gallegos, J.; Els, S.; Gracia, G.; Lock, T.; Mercier, E.; O'Mullane, W.

2012-09-01

161

Measurement of magnetic field aligned potential differences using high resolution conjugate photoelectron energy spectra  

NASA Technical Reports Server (NTRS)

Simultaneous high-resolution observations of a distinctive feature in the energy spectrum of conjugate photoelectrons and spacecraft potential relative to the local ionosphere have allowed the net potential difference between magnetic conjugate points at latitudes below the region of low-energy (i.e., lower than 100 eV) auroral electron precipitation to be determined. Measurements made at 300 km from Atmosphere Explorer C show that there is normally no net potential difference between hemispheres in this region, which extended up to invariant latitudes as high as 74 deg. Two types of apparently related anomalous behavior were infrequently observed at high latitudes. During these periods the incident flux of conjugate photoelectrons was either decelerated by about 3 eV or was not detected.

Peterson, W. K.; Doering, J. P.; Potemra, T. A.; Bostrom, C. O.; Brace, L. H.; Heelis, R. A.; Hanson, W. B.

1977-01-01

162

Comparative transforming potential of different human papillomaviruses associated with non-melanoma skin cancer  

SciTech Connect

It is well established that high-risk human papillomaviruses (HPVs) that infect mucosal epithelia are the causative agents of cervical cancer. In contrast, the association of cutaneo-tropic HPV types with the development of non-melanoma skin cancer (NMSC) is less well defined. In this study, we have analysed the in vitro transforming potential of various cutaneous HPV types. Using oncogene cooperation assays with activated ras, we have shown that diverse cutaneous types, including 12, 14, 15, 24, 36 and 49, have significant transforming potential. Interestingly, most of this activity appears to be encoded by the E6 gene product. In contrast, the common HPV-10 exhibits no significant transforming potential in these assays. This difference may be a reflection of different patterns of cellular localization, with transforming E6s being nuclear and non-transforming being cytoplasmic. These results provide molecular support for a role of these viruses in the development of certain human malignancies.

Massimi, Paola; Thomas, Miranda [International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012 Trieste (Italy); Bouvard, Veronique [Infections and Cancer Biology Group, International Agency for Research on Cancer - World Health Organization, 150 Cours Albert Thomas, 69372 Lyon (France); Ruberto, Irene [International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012 Trieste (Italy); Campo, M. Saveria [Division of Pathological Sciences, Institute of Comparative Medicine, University of Glasgow, Garscube Estate, Glasgow G61 1QH (United Kingdom); Tommasino, Massimo [Infections and Cancer Biology Group, International Agency for Research on Cancer - World Health Organization, 150 Cours Albert Thomas, 69372 Lyon (France); Banks, Lawrence [International Centre for Genetic Engineering and Biotechnology, Padriciano 99, I-34012 Trieste (Italy)], E-mail: banks@icgeb.org

2008-02-20

163

Study Role of Different Dimensions of Emotional Self-Regulation on Addiction Potential  

PubMed Central

Objective To investigate relationship between addiction potentiality and different dimensions of emotional self-regulation. Materials and methods This descriptive and correlational study included students of Sistan and Baluchistan University, Sistan and Baluchestan, Iran. Participants were selected by random sampling method. We applied Addiction Potential Scale (APS) and Difficult in Emotion Regulation Scale (DERS) for this study. For statistical analysis, Pearson correlation and regression analysis methods were used. Results The results show that there is a positive and significant relationship between the addiction potential and all dimensions of emotional self-regulation (excepting lack of awareness). The enter regression analysis for prediction of the APS by the DERS shows that the DERS predicts 16% of the APS variances. Conclusion Regard to the results, it is necessary to introduce an especial program in emotional self-regulation for the youth with addiction potential.

Kazemi, Yahya; Khosravy, Masoum

2014-01-01

164

Gravity wave kinetic, potential, and vertical fluctuation energies as indicators of different frequency gravity waves  

Microsoft Academic Search

An advantage of examining atmospheric gravity waves using high vertical-resolution radiosonde data over other measurement techniques is that horizontal wind, temperature, and vertical ascent rate can be measured directly. This allows the kinetic, potential, and vertical velocity fluctuation energies to be derived independently. Each of these gravity wave energies is shown to have sensitivity to different gravity wave frequencies. Observed

Marvin A. Geller; Jie Gong

2010-01-01

165

Different Arbuscular Mycorrhizal Fungal Species Are Potential Determinants of Plant Community Structure  

Microsoft Academic Search

Almost all natural plant communities contain arbuscular mycorrhizal fungi (AMF). We hypothesized that the species composition of AMF communities could have the potential to determine plant community structure if the growth response to different AMF species or to communities of AMF species varies among plant species. To test the existence of such a differential response we conducted a pot experiment

Thomas Boller; Andres Wiemken; Ian R. Sanders

1998-01-01

166

Application of finite differences in conjunction with the method of local potential in hydrodynamic stability  

Microsoft Academic Search

The finite difference method was applied in conjunction with the theory of the local potential in order to solve numerically the Orr-Sommerfeld equation for Poiseuille flow between two parallel and infinite plates. The apparent advantages of this approach are that one does not require the use of trial functions, which in previous attempts have led to low-accuracy results on the

T. Vanderborck; J. K. Platten

1975-01-01

167

Large volcanoes on Venus: Examples of geologic and structural characteristics from different classes  

NASA Technical Reports Server (NTRS)

Large volcanoes characterized by radial lava flows and similar evidence for a topographic edifice are widely distributed over the surface of Venus and geologically diverse. Based on the global identification of more than 165 examples and preliminary geologic mapping, large volcanoes range from those characterized geologically as simple lava edifices to those bearing evidence of complexly developed volcanic and structural histories. Many large volcanoes exhibit characteristics transitional to other large magnetic center types such as coronae and novae. In this study, we examine the geology and structure of several type examples of large volcanoes not addressed in previous studies which are representative of several of the morphological classes.

Crumpler, L. S.; Head, J. W.; Aubele, J. C.

1993-01-01

168

Estimating Large-Customer Demand Response Market Potential:Integrating Price and Customer Behavior.  

National Technical Information Service (NTIS)

Demand response (DR) is increasingly recognized as an essential ingredient to well-functioning electricity markets. DR market potential studies can answer questions about the amount of DR available in a given area, from which market segments. Several rece...

B. Neenan C. Goldman N. Hopper P. Cappers R. Bharvirkar

2007-01-01

169

Large current difference in Au-coated vertical silicon nanowire electrode array with functionalization of peptides.  

PubMed

Au-coated vertical silicon nanowire electrode array (VSNEA) was fabricated using a combination of bottom-up and top-down approaches by chemical vapor deposition and complementary metal-oxide-semiconductor process for biomolecule sensing. To verify the feasibility for the detection of biomolecules, Au-coated VSNEA was functionalized using peptides having a fluorescent probe. Cyclic voltammograms of the peptide-functionalized Au-coated VSNEA show a steady-state electrochemical current behavior. Because of the critically small dimension and vertically aligned nature of VSNEA, the current density of Au-coated VSNEA was dramatically higher than that of Au film electrodes. Au-coated VSNEA further showed a large current difference with and without peptides that was nine times more than that of Au film electrodes. These results indicate that Au-coated VSENA is highly effective device to detect peptides compared to conventional thin-film electrodes. Au-coated VSNEA can also be used as a divergent biosensor platform in many applications. PMID:24279451

Kim, Ilsoo; Kim, So-Eun; Han, Sanghun; Kim, Hyungsuk; Lee, Jaehyung; Jeong, Du-Won; Kim, Ju-Jin; Lim, Yong-Beom; Choi, Heon-Jin

2013-01-01

170

Why are small and large numbers enumerated differently? A limited-capacity preattentive stage in vision.  

PubMed

"Subitizing," the process of enumeration when there are fewer than 4 items, is rapid (40-100 ms/item), effortless, and accurate. "Counting," the process of enumeration when there are more than 4 items, is slow (250-350 ms/item), effortful, and error-prone. Why is there a difference in the way the small and large numbers of items are enumerated? A theory of enumeration is proposed that emerges from a general theory of vision, yet explains the numeric abilities of preverbal infants, children, and adults. We argue that subitizing exploits a limited-capacity parallel mechanism for item individuation, the FINST mechanism, associated with the multiple target tracking task (Pylyshyn, 1989; Pylyshyn & Storm, 1988). Two kinds of evidence support the claim that subitizing relies on preattentive information, whereas counting requires spatial attention. First, whenever spatial attention is needed to compute a spatial relation (cf. Ullman, 1984) or to perform feature integration (cf. Treisman & Gelade, 1980), subitizing does not occur (Trick & Pylyshyn, 1993a). Second, the position of the attentional focus, as manipulated by cue validity, has a greater effect on counting than subitizing latencies (Trick & Pylyshyn, 1993b). PMID:8121961

Trick, L M; Pylyshyn, Z W

1994-01-01

171

Chemical changes in different types of coal ash during prolonged, large scale, contact with seawater.  

PubMed

In this study, we followed the chemical changes occurring in coal ash exposed to prolonged (300 days), large scale, contact with running seawater. Four major components (Al, Ca, Mg, Fe) and seven minor and trace elements (Cd, Cr, Cu, Mn, Zn, Pb, Hg) were measured in four coal ash types: fly and bottom ash freshly obtained from coal-fired power plant, and old ash (crushed and blocks) recovered from the sea after 3-5 years contact with seawater. Changes occurred in the chemical composition of the coal ash along the experiment: Fe increased in fresh ash, Al increased in old ash and Ca increased in all ash types except old ash blocks. Cu and Hg decreased in fresh fly ash while Cr increased, Cd decreased in all ash types except bottom ash, and Mn decreased in bottom ash. Most of the changes occurred in the fresh fly ash, and not in the old ash, indicating equilibrium after prior exposure to seawater. In addition, more changes occurred in fresh fly ash than in bottom ash, emphasizing the differences between the two ash types. While the changes in the concentrations of the major elements may be an indication of the integrity of the ash matrix, the only elements of environmental significance released to the environment were Hg and Cd. However, calculated seawater concentrations were much lower than seawater quality criteria and therefore the coal ash was considered suitable for marine applications concerning seawater quality. PMID:12623087

Shoham-Frider, Efrat; Shelef, Gedaliah; Kress, Nurit

2003-01-01

172

Large Vestibular Evoked Myogenic Potentials in Response to Bone-Conducted Sounds in Patients with Superior Canal Dehiscence Syndrome  

Microsoft Academic Search

Dehiscence of the superior semicircular canal is a ‘new’ vestibular entity. Among these patients, the vestibular evoked myogenic potentials (VEMP) in response to air-conducted sounds are large. In the present study, VEMP in response to bone-conducted sounds were studied in 5 normal subjects, in 3 patients after (unilateral) labyrinthectomy and in 4 patients with (unilateral) superior canal dehiscence syndrome. The

Krister Brantberg; Lennart Löfqvist; Per-Anders Fransson

2004-01-01

173

Evaluation of light regulatory potential of Calvin cycle steps based on large-scale gene expression profiling data  

Microsoft Academic Search

Although large-scale gene expression data have been studied from many perspectives, they have not been systematically integrated to infer the regulatory potentials of individual genes in specific pathways. Here we report the analysis of expression patterns of genes in the Calvin cycle from 95 Arabidopsis microarray experiments, which revealed a consistent gene regulation pattern in most experiments. This identified pattern,

Ning Sun; Ligeng Ma; Deyun Pan; Hongyu Zhao; Xing Wang Deng

2003-01-01

174

Consistency of mixing height retrieved over a large spatial domain from different data sources  

NASA Astrophysics Data System (ADS)

The monitoring of GreenHouse Gases (GHG) fluxes over large domains is performed coupling measurements with transport models. A key parameter, for successfully quantifying the fluxes is the altitude of the capping inversion, or the mixing height (MH). This parameter is commonly estimated as a diagnostic variable within global models, or estimated using radiosonde data. Both these methods have problems in representing the MH. In particular the time evolution and the spatial representation are the weakest aspects. Within the context of the Integrated Carbon Observation System (ICOS), a network of measurement stations is going to be created. Together with a complete equipment of instruments for measuring GHG concentrations and meteorological quantities, it is planed to monitor the MH using ceilometers and lidars. Ceilometers are a less expensive version of lidars, they are capable to estimate aerosolic load and within almost the first two kilometers the molecular density. The estimations are obtained looking for relevant time and space fluctuations of aerosol concentration. This is equivalent to placing the MH over an strong variation of the measured signal. So the most of the algorithms for locating MH are edge detection algorithms. The evaluation of the MH, estimated with different algorithms applied to optical data, shows bad agreement with the estimate performed on radiosonde data. However, a deeper study on the automated methods used on radiosonde data reveals that the commonly used algorithms, based on different implementations of Richardson Bulk Number method, are not reliable or suitable for evaluating results of other methods. The use of optical instruments for estimating MH has several limitations: multiple edges are commonly detected and a selection criteria is required; depending on the stability of the boundary layer MH can be outside the detection limits of the instrument; clouds and other water condensations phenomena can prevent the estimation of MH. Applications of such instruments is tested over a wide domain covering the German Weather Service network of ceilometers and the estimations are compared to different methods of estimating MH, in particular: geostatistical interpolation of MH estimated with radiosonde; distance weighted interpolations of MH estimated with radiosonde; direct comparison of co-located ceilometer and radiosonde. The results reveal the need of developing a more appropriate approach for using both radiosonde and optical methods in an automated context.

Biavati, Gionata; Feist, Dietrich G.

2014-05-01

175

Colorectal carcinomas with microsatellite instability display a different pattern of target gene mutations according to large bowel site of origin  

PubMed Central

Background Only a few studies have addressed the molecular pathways specifically involved in carcinogenesis of the distal colon and rectum. We aimed to identify potential differences among genetic alterations in distal colon and rectal carcinomas as compared to cancers arising elsewhere in the large bowel. Methods Constitutional and tumor DNA from a test series of 37 patients with rectal and 25 patients with sigmoid carcinomas, previously analyzed for microsatellite instability (MSI), was studied for BAX, IGF2R, TGFBR2, MSH3, and MSH6 microsatellite sequence alterations, BRAF and KRAS mutations, and MLH1 promoter methylation. The findings were then compared with those of an independent validation series consisting of 36 MSI-H carcinomas with origin from each of the large bowel regions. Immunohistochemical and germline mutation analyses of the mismatch repair system were performed when appropriate. Results In the test series, IGFR2 and BAX mutations were present in one and two out of the six distal MSI-H carcinomas, respectively, and no mutations were detected in TGFBR2, MSH3, and MSH6. We confirmed these findings in the validation series, with TGFBR2 and MSH3 microsatellite mutations occurring less frequently in MSI-H rectal and sigmoid carcinomas than in MSI-H colon carcinomas elsewhere (P = 0.00005 and P = 0.0000005, respectively, when considering all MSI-carcinomas of both series). No MLH1 promoter methylation was observed in the MSI-H rectal and sigmoid carcinomas of both series, as compared to 53% found in MSI-H carcinomas from other locations (P = 0.004). KRAS and BRAF mutational frequencies were 19% and 43% in proximal carcinomas and 25% and 17% in rectal/sigmoid carcinomas, respectively. Conclusion The mechanism and the pattern of genetic changes driving MSI-H carcinogenesis in distal colon and rectum appears to differ from that occurring elsewhere in the colon and further investigation is warranted both in patients with sporadic or hereditary disease.

2010-01-01

176

Potential for Large-Diameter NTD Silicon Production in the Advanced Test Reactor.  

National Technical Information Service (NTIS)

The Advanced Test Reactor (ATR) is a 250-MW(t) flux-trap reactor located at the Idaho National Engineering Laboratory (INEL). Within the reflector are four 124-mm-diameter I-holes, which are available for silicon irradiation. Two large irradiation volumes...

J. S. Herring R. E. Korenke

1984-01-01

177

On the Potentials of Parallelizing Large Neighbourhood Search for Rich Vehicle Routing Problems  

Microsoft Academic Search

\\u000a In this paper we present preliminary results on parallelizing the Large Neighbourhood Search heuristic (LNS) for the Vehicle\\u000a Routing Problem with Pickup and Delivery and Time Windows (VRPPDTW) using pb.net, a framework for easy and efficient parallelization\\u000a of problem solving heuristics.

Paul Bartodziej; Ulrich Derigs; Ulrich Vogel

2010-01-01

178

Rainbows in rotationally inelastic scattering: a comparative study of different model potential surfaces and dynamical approximations  

SciTech Connect

Rainbow structures in rotationally elastic and inelastic differential cross sections in atom--diatom collisions are investigated by comparison of three model potential energy surfaces labeled I, II, and III which are represented by V(R,..gamma..) = V/sub 0/(R)+V/sub 2/(R)P/sub 2/(cos ..gamma..). The cross sections are calculated within the quantal infinite-order-sudden (IOS) approximation. The anisotropic part V/sub 2/ is the same for all potentials and purely repulsive. The isotropic part V/sub 0/ for potential I is also repulsive and the differential cross sections show the well-studied rotational rainbow structures. Structural changes occur for collisions in potential II and III which have V/sub 0/ terms being attractive at intermediate and large atom--molecule separations and having well depths of 10% and 25% of the collision energy, respectively. For example, the elastic cross section has no classical rainbow in the case of potential I but three in the case of potential III. The rainbow structures are analyzed within the classical and semiclassical versions of the IOS approximation and interpreted in terms of catastrophe theory. The quantitative comparison of the classical with the quantal IOS cross sections manifests possible quantum effects, i.e., tunneling into nonclassical regions and interference effects due to the superposition of several contributions (up to six in the present study). They can be very prominent and thus we conclude that much caution is needed if experimental data are compared with classical calculations. The accuracy of the IOS approximation is tested by comparison of classical IOS cross sections with cross sections obtained from exact classical trajectory calculations. The agreement is generally good with the exemption of the rainbow region and small angle, rotationally elastic scattering.

Schinke, R.; Korsch, H.J.; Poppe, D.

1982-12-15

179

Large Sex Differences in Chicken Behavior and Brain Gene Expression Coincide with Few Differences in Promoter DNA-Methylation.  

PubMed

While behavioral sex differences have repeatedly been reported across taxa, the underlying epigenetic mechanisms in the brain are mostly lacking. Birds have previously shown to have only limited dosage compensation, leading to high sex bias of Z-chromosome gene expression. In chickens, a male hyper-methylated region (MHM) on the Z-chromosome has been associated with a local type of dosage compensation, but a more detailed characterization of the avian methylome is limiting our interpretations. Here we report an analysis of genome wide sex differences in promoter DNA-methylation and gene expression in the brain of three weeks old chickens, and associated sex differences in behavior of Red Junglefowl (ancestor of domestic chickens). Combining DNA-methylation tiling arrays with gene expression microarrays we show that a specific locus of the MHM region, together with the promoter for the zinc finger RNA binding protein (ZFR) gene on chromosome 1, is strongly associated with sex dimorphism in gene expression. Except for this, we found few differences in promoter DNA-methylation, even though hundreds of genes were robustly differentially expressed across distantly related breeds. Several of the differentially expressed genes are known to affect behavior, and as suggested from their functional annotation, we found that female Red Junglefowl are more explorative and fearful in a range of tests performed throughout their lives. This paper identifies new sites and, with increased resolution, confirms known sites where DNA-methylation seems to affect sexually dimorphic gene expression, but the general lack of this association is noticeable and strengthens the view that birds do not have dosage compensation. PMID:24782041

Nätt, Daniel; Agnvall, Beatrix; Jensen, Per

2014-01-01

180

Large Sex Differences in Chicken Behavior and Brain Gene Expression Coincide with Few Differences in Promoter DNA-Methylation  

PubMed Central

While behavioral sex differences have repeatedly been reported across taxa, the underlying epigenetic mechanisms in the brain are mostly lacking. Birds have previously shown to have only limited dosage compensation, leading to high sex bias of Z-chromosome gene expression. In chickens, a male hyper-methylated region (MHM) on the Z-chromosome has been associated with a local type of dosage compensation, but a more detailed characterization of the avian methylome is limiting our interpretations. Here we report an analysis of genome wide sex differences in promoter DNA-methylation and gene expression in the brain of three weeks old chickens, and associated sex differences in behavior of Red Junglefowl (ancestor of domestic chickens). Combining DNA-methylation tiling arrays with gene expression microarrays we show that a specific locus of the MHM region, together with the promoter for the zinc finger RNA binding protein (ZFR) gene on chromosome 1, is strongly associated with sex dimorphism in gene expression. Except for this, we found few differences in promoter DNA-methylation, even though hundreds of genes were robustly differentially expressed across distantly related breeds. Several of the differentially expressed genes are known to affect behavior, and as suggested from their functional annotation, we found that female Red Junglefowl are more explorative and fearful in a range of tests performed throughout their lives. This paper identifies new sites and, with increased resolution, confirms known sites where DNA-methylation seems to affect sexually dimorphic gene expression, but the general lack of this association is noticeable and strengthens the view that birds do not have dosage compensation.

Natt, Daniel; Agnvall, Beatrix; Jensen, Per

2014-01-01

181

Does One Soros Make a Difference? A Theory of Currency Crises with Large and Small Traders  

Microsoft Academic Search

Do large investors increase the vulnerability of a country to speculative attacks in the foreign exchange markets? To address this issue, we build a model of currency crises where a single large investor and a continuum of small investors independently decide whether to attack a currency based on their private information about fundamentals. Even abstracting from signalling, the presence of

Giancarlo Corsetti; Amil Dasgupta; Stephen Morris; Hyun Song Shin

2004-01-01

182

Large-scale controls on potential respiration and denitrification in riverine floodplains  

PubMed Central

Restoration measures of deteriorated river ecosystems generally aim at increasing the spatial heterogeneity and connectivity of these systems in order to increase biodiversity and ecosystem stability. While this is believed to benefit overall ecological integrity, consequences of such restoration projects on biogeochemical processes per se (i.e. ecosystem functioning) in fluvial systems are rarely considered. We address these issues by evaluating the characteristics of surface water connection between side arms and the main river channel in a former braided river section and the role and degree of connectivity (i.e. duration of surface water connection) on the sediment biogeochemistry. We hypothesized that potential respiration and denitrification would be controlled by the degree of hydrological connectivity, which was increased after floodplain restoration. We measured potential microbial respiration (SIR) and denitrification (DEA) and compared a degraded floodplain section of the Danube River with a reconnected and restored floodplain in the same river section. Re-establishing surface water connection altered the controls on sediment microbial respiration and denitrification ultimately impacting potential microbial activities. Meta-variables were created to characterize the effects of hydrology, morphology, and the available carbon and nutrient pools on potential microbial processing. Mantel statistics and path analysis were performed and demonstrate a hierarchy where the effects of hydrology on the available substrates and microbial processing are mediated by the morphology of the floodplain. In addition, these processes are highest in the least connected sites. Surface water connection, mediated by morphology regulates the potential denitrification rate and the ratio of N2O to N2 emissions, demonstrating the effects of restoration in floodplain systems.

Welti, Nina; Bondar-Kunze, Elisabeth; Singer, Gabriel; Tritthart, Michael; Zechmeister-Boltenstern, Sophie; Hein, Thomas; Pinay, Gilles

2012-01-01

183

Ab initio potential energy surfaces of Ar-NH3 for different NH3 umbrella angles  

NASA Astrophysics Data System (ADS)

Four ab initio potential energy surfaces of the van der Waals system argon-ammonia are computed for the following four different HNH ('umbrella') angles of ammonia: 100 deg, 106.67 deg, 113.34 deg, and 120 deg. These potentials have been obtained by Heitler-London short-range calculations and from multipole-expanded dispersion and induction long-range contributions. A Tang-Toennies-like damping is applied to the long-range energy. Each surface is given analytically in the form of a spherical harmonic expansion through l = 7, where the expansion functions depend on the polar angles of the argon atom with respect to the principal axes of NH3. The expansion coefficients are represented by functions depending on the distance between the monomers. The potential for the equilibrium HNH angle 106.67 deg is applied to the computation of interaction virial coefficients in which quantum effects are included.

Bulski, M.; Wormer, P. E. S.; van der Avoird, A.

1991-01-01

184

Antioxidant, total phenolic contents and antinociceptive potential of Teucrium stocksianum methanolic extract in different animal models  

PubMed Central

Background Oxidative stress and analgesia are connected with different pathological conditions. The drug candidates from synthetic sources are associated with various side effects; therefore, researchers are giving priority to find novel, effective and safe phytomedicines. Teucrium species possesses antioxidant, analgesic, anti-inflammatory and hepatoprotective activities. The essential oils of Teucrium stocksianum have shown strong antinociceptive potential. Our current study is designed to embark total phenolic content (TPC), antioxidant and antinociceptive potential of the methanolic extract of Teucrium stocksianum (METS). Method Phytochemical composition was determined by using standard methods. Free radical scavenging potential and TPC of METS were assessed by using 2, 2-diphenyl-1-picryl-hydrazyl (DPPH) and Folin-Ciocalteu Reagent (FCR) respectively. Antinociceptive potential was determined by acetic acid induced abdominal writhing, formalin induced paw licking and tail immersion tests. Different test dose 50, 100 and 150 mg/kg body weight of METS were administered intra peritonealy (i.p) to various groups of mice for the evaluation of analgesic potential. Results Phytochemical screening confirmed the presence of flavonoids, tannins, saponins, anthraquinone, steroid, phlobatannin, terpenoid, glycoside and reducing sugars. METS was found safe at a dose of 1000 mg/kg body weight. A concentration dependent free radical scavenging effect was observed with methanolic aerial parts extract of Teucrium stocksianum (MAPETS) and methanolic roots extracts of Teucrium stocksianum (MRETS). MAPETS and MRETS have shown highest antioxidant activity 91.72% and 86.19% respectively at 100 ?g/ml. MAPETS was found more rich (115.32 mg of GAE/g of dry material) in TPC as compared to MAPETS (105.41 mg of GAE/g). METS demonstrated a dose dependent antinociceptive potential in different pain models, like in acetic acid, formalin and tail immersion showing 83.103%, 80.872% and 67.58% at a dose of 150 mg/kg, similar to acetylsalicylic acid (74.79%, 82.87%, 100 mg/kg) and TramadolR (74%, 30 mg/kg) respectively. Conclusion Strong antioxidant potential and high TPCs are residing in the methanolic extract of T. stocksianum. METS showed analgesic potential in all models of nociception implying that both peripheral and central pathways of analgesia are involved. This might be due to the presence of various classes of phytochemicals in the plant extract.

2014-01-01

185

Using finite difference and differential transformation method to analyze of large deflections of orthotropic rectangular plate problem  

Microsoft Academic Search

This paper analyses the large deflections of an orthotropic rectangular clamped and simply supported thin plate. A hybrid method which combines the finite difference method and the differential transformation method is employed to reduce the partial differential equations describing the large deflections of the orthotropic plate to a set of algebraic equations. The simulation results indicate that significant errors are

Yen-liang Yeh; Cheng Chi Wang; Ming-jyi Jang

2007-01-01

186

Electrical potential differences in cells of barley roots and their relation to ion uptake.  

PubMed

Single cell electropotentials of barley (Hordeum vulgare L., cv. ;Compana') root cortex were measured at different external concentrations of KCl in the presence of Ca(2+). The roots were low in salt from seedlings grown on 0.5 mm aerated CaSO(4) solution. Thus, the conditions were equivalent to those used to define the dual mechanisms found with radioactive tracer-labeled ion uptake. In 0.5 mm CaSO(4) alone, there is an increase with time of cell negativity from about -65 millivolts 15 minutes after cutting segments to about -185 millivolts in 6 to 8 hours. Two possible hypotheses, not mutually exclusive, are offered to explain this aging effect: that cutting exposes plasmodesmata which are leaky initially but which seal in time, and that some internal factors, e.g., hormones diffusing from the apex, have a regulatory effect on the cell potential, an influence which becomes dissipated in isolated segments and permits the development of a higher potential difference. In any case changes in selective ion transport must be involved. The cell potentials at KCl concentrations above 2.0 mm are more negative than would be expected for a passive diffusion potential. It is suggested that this discrepancy may be due to an electrogenic pump or to a higher K(+) concentration in the cytoplasm than in the remainder of the cell, or perhaps to both. Whether there is a clear relationship between cell potential and mechanisms 1 and 2 of cation transport depends upon whether the cell potentials of freshly cut or of aged tissue represent the values relevant to intact roots. PMID:16657583

Pitman, M G; Mertz, S M; Graves, J S; Pierce, W S; Higinbotham, N

1971-01-01

187

Large breasts and narrow waists indicate high reproductive potential in women  

Microsoft Academic Search

Physical characteristics, such as breast size and waist-to-hip ratio (WHR), function as important features used by human males to assess female attractiveness. Males supposedly pay attention to these features because they serve as cues to fecundity and health. Here, we document that women with higher breast- to-underbreast ratio (large breasts) and women with relatively low WHR (narrow waists) have higher

Grazyna Jasienska; Anna Ziomkiewicz; Peter T. Ellison; Susan F. Lipson; Inger Thune

2004-01-01

188

The Effective Group Potential, a New Method for the Study of Spectrum in Large Molecules: Tests and Perspectives  

SciTech Connect

The new method, called effective group potential, which generalizes the concept of effective core potential by including in a potential the effects of many atoms ligand, is used to calculate transition energies. Three molecules containing a metal atom (Cu, Cr, Ni) surrounded by NH3 ligands have been studied. It is shown that by replacing the NH3 group by an effective group potential, the characteristic transitions energies are very well reproduced at various ab initio levels. The transitions studied are transitions between open shells on the metallic center but also ligand to metal transitions where, though unexpected, quite reliable results were also obtained. This method is thus very well suited for the study of the spectrum of a large molecule under the condition that a separation between an active part plus some spectator groups can be made, a condition satisfied in most organometallic molecules as well as in biological molecules.

Heully, Jean-Louis; Poteau, Romuald; Berasaluce, Sandra; Alary, Fabienne

2002-03-22

189

The effective group potential, a new method for the study of spectrum in large molecules: Tests and perspectives  

NASA Astrophysics Data System (ADS)

The new method, called effective group potential, which generalizes the concept of effective core potential by including in a potential the effects of many atoms ligand, is used to calculate transition energies. Three molecules containing a metal atom (Cu, Cr, Ni) surrounded by NH3 ligands have been studied. It is shown that by replacing the NH3 group by an effective group potential, the characteristic transitions energies are very well reproduced at various ab initio levels. The transitions studied are transitions between open shells on the metallic center but also ligand to metal transitions where, though unexpected, quite reliable results were also obtained. This method is thus very well suited for the study of the spectrum of a large molecule under the condition that a separation between an active part plus some spectator groups can be made, a condition satisfied in most organometallic molecules as well as in biological molecules.

Heully, Jean-Louis; Poteau, Romuald; Berasaluce, Sandra; Alary, Fabienne

2002-03-01

190

Hyperdense large artery sign in meningitis: A marker of ominous thrombogenic potential of pneumococcus?  

PubMed Central

Hyperdensity in the middle cerebral artery (MCA) or posterior cerebral artery (PCA) on non-contrast head CT, suggests the presence of a thrombus inside these vessels, often referred to as the “MCA sign” or “PCA sign” respectively. These two signs are classically associated with strokes secondary to cardiovascular etiologies and are only infrequently reported with other types of stroke. Whereas stroke is a recognized complication of pneumococcal meningitis hyperdense large vessel sign (in this case a combination of MCA and PCA) has not been previously reported. We report a case of rapidly progressive pneumococcal meningitis that presented as acute stroke involving large vessels in the vicinity of the circle of Willis in a patient with a history of non-Hodgkin lymphoma (NHL) in remission for 6 years. This patient had received a week of high dose steroids before admission. Head CT scan on admission showed the presence of hyperdense MCA and PCA signs. The patient rapidly deteriorated and a follow-up head CT revealed diffuse brain edema and increased density in the basal cisterns without evidence of sub arachnoid hemorrhage. Tc99m exametazime brain flow scan showed no intracerebral blood flow both supra and infratentorially. Steptococcus pneumoniae, NHL cells and high-dose steroid use can upregulate tissue factor synthesis and may have led to a hypercoagulable state via activation of the extrinsic pathway in the large intracerbral arteries.

Mojumder, Deb Kumar; Toledo, John De

2014-01-01

191

Antioxidative and antiinflammatory potential of different functional drink concepts in vitro.  

PubMed

The present study was undertaken to investigate the antioxidative effects of three different functional drink concepts especially designed to improve the body's performance and function and to possess high antioxidant activities. The concepts based on the mixture of various plant ingredients were: (1) eQ - equalize your nutrient balance, brain line [acerola-dragon fruit], (2) eQ - equalize your nutrient balance, beauty line [honey-pepper] and (3) Let's get red [intense]. By using a cell-based test assay, the study investigated the potential of the functional drinks to inactivate reactive superoxide anion radicals generated by inflammation-mediating cells as well as the effect on basal metabolism of these cells (antioxidant and antiinflammatory potential). In addition, by using a cell-free test assay the potential of the drinks to inactivate free exogenous superoxide anion radicals (scavenger effect) was investigated. The data presented here demonstrate the different radical scavenging, antioxidant and anti-inflammatory potential of the functional drink concepts. In particular Let's get red [intense] turned out to be the most potent drink in this respect and demonstrated marked efficacy in scavenging, antioxidant and antiinflammatory action. PMID:18979495

Dartsch, Peter C; Kler, Adolf; Kriesl, Erwin

2009-02-01

192

Mineralization of hormones in breeder and broiler litters at different water potentials and temperatures.  

PubMed

When poultry litter is landspread, steroidal hormones present in the litter may reach surface waters, where they may have undesirable biological effects. In a laboratory study, we determined the mineralization of [4-14C]-labeled 17beta-estradiol, estrone, and testosterone in breeder litter at three different water potentials (-56, -24, and -12 MPa) and temperatures (25, 35, and 45 degrees C), and in broiler litter at two different water potentials (-24 and -12 MPa) and temperatures (25 and 35 degrees C). Mineralization was similar in both litters and generally increased with increasing water content and decreasing temperature. After 23 wk at -24 MPa, an average of 27, 11, and <2% of the radiolabeled testosterone applied to breeder litter was mineralized to 14CO2 at 25, 35, and 45 degrees C, respectively. In contrast, mineralization of the radiolabeled estradiol and estrone was <2% after 25 wk at all water potentials, except after 17 wk at 25 degrees C and -12 MPa, where up to 5.9% of the estradiol and 7.8% of the estrone was mineralized. The minimal mineralization suggests that the litters may still be potential sources of hormones to surface and subsurface waters. PMID:16585611

Hemmings, Sarah N J; Hartel, Peter G

2006-01-01

193

Relationships between nasal potential difference and respiratory function in adults with cystic fibrosis  

Microsoft Academic Search

This study investigated the relations between nasal transepithelial elec- tric potential difference (PD) and the phenotype and genotype of cystic fibrosis (CF) adult patients. Basal nasal PD was measured in 95 adult CF patients who were classified into three groups of nasal PD (expressed as absolute values) according to the 10th and the 90th percentiles (28.3 and 49.2 mV, respectively),

I. Fajac; D. Hubert; T. Bienvenu; B. Richaud-Thiriez; R. Matran; J. C. Kaplan; J. Dall'Ava-Santucci; D. J. Dusser

1998-01-01

194

Generalized energy and potential enstrophy conserving finite difference schemes for the shallow water equations  

NASA Technical Reports Server (NTRS)

The conditions under which finite difference schemes for the shallow water equations can conserve both total energy and potential enstrophy are considered. A method of deriving such schemes using operator formalism is developed. Several such schemes are derived for the A-, B- and C-grids. The derived schemes include second-order schemes and pseudo-fourth-order schemes. The simplest B-grid pseudo-fourth-order schemes are presented.

Abramopoulos, Frank

1988-01-01

195

Mineralization of Hormones in Breeder and Broiler Litters at Different Water Potentials and Temperatures  

Microsoft Academic Search

When poultry litter is landspread, steroidal hormones present in the litter may reach surface waters, where they may have undesirable biological effects. In a laboratory study, we determined the mineral- ization of (4- 14 C)-labeled 17b-estradiol, estrone, and testosterone in breeder litter at three different water potentials (256, 224, and 212 MPa) and temperatures (25, 35, and 45C), and in

Sarah N. J. Hemmings; Peter G. Hartel

2006-01-01

196

Performance assessment of different constraining potentials in computational structure prediction for disulfide-bridged proteins.  

PubMed

The presence of disulfide bonds in proteins has very important implications on the three-dimensional structure and folding of proteins. An adequate treatment of disulfide bonds in de-novo protein simulations is therefore very important. Here we present a computational study of a set of small disulfide-bridged proteins using an all-atom stochastic search approach and including various constraining potentials to describe the disulfide bonds. The proposed potentials can easily be implemented in any code based on all-atom force fields and employed in simulations to achieve an improved prediction of protein structure. Exploring different potential parameters and comparing the structures to those from unconstrained simulations and to experimental structures by means of a scoring function we demonstrate that the inclusion of constraining potentials improves the quality of final structures significantly. For some proteins (1KVG and 1PG1) the native conformation is visited only in simulations in presence of constraints. Overall, we found that the Morse potential has optimal performance, in particular for the ?-sheet proteins. PMID:21864792

Kondov, Ivan; Verma, Abhinav; Wenzel, Wolfgang

2011-08-10

197

Large-scale synthesis, characterization and microwave absorption properties of carbon nanotubes of different helicities  

Microsoft Academic Search

Carbon nanotubes of high helicity (H-HCNTs, Sample A) have been synthesized in large-scale by pyrolysis of acetylene at 450°C over Fe nanoparticles derived from coprecipitation\\/hydrogen reduction method. With controlled introduction of hydrogen during acetylene pyrolysis, CNTs of low helicity (L-HCNTs, Sample B) and worm-like CNTs (Sample C) were obtained in large quantities. The yields of the CNTs products are high,

Xiaosi Qi; Yi Yang; Wei Zhong; Yu Deng; Chaktong Au; Youwei Du

2009-01-01

198

The Persistence and Pricing of Earnings, Accruals, and Cash Flows When Firms Have Large Book-Tax Differences  

Microsoft Academic Search

I investigate the role of book-tax differences in indicating the persistence of earnings, accruals, and cash flows for one-period-ahead earnings. I also examine whether the level of book-tax differences influences investors' assessments of future earnings persistence. I find that firm-years with large book-tax differences have earn- ings that are less persistent than firm-years with small book-tax differences. Further, the evidence

Michelle Hanlon

2004-01-01

199

Assessment of different colour parameters for discriminating potential suspended sediment sources and provenance: A multi-scale study in Luxembourg  

NASA Astrophysics Data System (ADS)

Sediment colour has recently been used successfully to estimate suspended sediment sources in small catchments using the fingerprinting approach. The methodology offers opportunity for further research since it provides a rapid and cheap means for investigating sediment sources. However, the colour-based fingerprinting approach has not yet been tested in medium and large catchments. This paper aims to test whether colour parameters are capable of discriminating sediment sources in a nested system of seven sub-catchments ranging from 0.7 to 247 km 2 of the Attert River catchment, NW Luxembourg. Time-integrated suspended sediment samples and samples of potential sediment sources (land-use types and channel banks) were collected in all catchments. Sediment colour was then computed from diffuse reflectance spectrometry measurements (ASD FieldSpec-II spectrometer, 0.4-2.5 µm) taken over the visible wavelength range. Twenty-four colour parameters were derived from several colour space models (CIE xyY, CIE XYZ, RGB, Munsell HVC, Helmholtz chromaticity, CIELUV and CIELAB) and their ability to discriminate potential suspended sediment sources and provenance was evaluated and compared. Results demonstrated that time-integrated suspended sediment samples collected in the study catchments had statistically different colour values. Moreover, these values always represented a mixture of the colour values measured on potential suspended sediment sources in the catchment. Inter-source colour contrasts (land-use types and channel banks) were observed in all catchments (Kruskal-Wallis H-test). However, although colour is able to distinguish potential sediment sources in small catchments, the level of source discrimination decreases as the catchment size increases, probably due to heterogeneous geology and pedology, intra-source variability and to source overlap. Nevertheless, in the studied medium-sized catchments (ranging from 19.4 to 247 km 2), colour could differentiate between topsoil and sub-surface (i.e. channel bank) material and/or up to three sources types. No single colour model had discrimination power across catchments, instead in each catchment a different combination of colour parameters gathered from different colour space models produced optimal discrimination of potential sediment sources. Furthermore, a colour-based fingerprinting approach did not possess potential for integrating spatial provenance and source type information because colour parameters could not discriminate between contrasting geological sub-areas. In summary, although colour parameters were not capable of discriminating the range of land-use type and channel banks as potential suspended sediment sources in medium-sized catchments, they afford substantial information and could be integrated into the classical fingerprinting approach together with other constituents (e.g. geochemistry, radionuclides and/or organic compounds).

Martínez-Carreras, Núria; Krein, Andreas; Gallart, Francesc; Iffly, Jean F.; Pfister, Laurent; Hoffmann, Lucien; Owens, Philip N.

2010-05-01

200

The effects of luminance contribution from large fields to chromatic visual evoked potentials.  

PubMed

Though useful from a clinical and practical standpoint uniform, large-field chromatic stimuli are likely to contain luminance contributions from retinal inhomogeneities. Such contribution can significantly influence psychophysical thresholds. However, the degree to which small luminance artifacts influence the chromatic VEP has been debated. In particular, claims have been made that band-pass tuning observed in chromatic VEPs result from luminance intrusion. However, there has been no direct evidence presented to support these claims. Recently, large-field isoluminant stimuli have been developed to control for intrusion from retinal inhomogeneities with particular regard to the influence of macular pigment. We report here the application of an improved version of these full-field stimuli to directly test the influence of luminance intrusion on the temporal tuning of the chromatic VEP. Our results show that band-pass tuning persists even when isoluminance is achieved throughout the extent of the stimulus. In addition, small amounts of luminance intrusion affect neither the shape of the temporal tuning function nor the major components of the VEP. These results support the conclusion that the chromatic VEP can depart substantially from threshold psychophysics with regard to temporal tuning and that obtaining a low-pass function is not requisite evidence of selective chromatic activation in the VEP. PMID:24384402

Skiba, Rafal M; Duncan, Chad S; Crognale, Michael A

2014-02-01

201

Comparison of three different approaches to estimate evapotranspiration over large areas: remotely sensed method, complementary approach and SVAT model.  

NASA Astrophysics Data System (ADS)

Methods able to accurately estimate ET over large areas are important for many applications. Spatial mapping of evapotranspiration (ET) is a prerequisite to a wide range of studies in hydrology, forestry, land and crop management, irrigation, water resources planning, etc. In this study, three different approaches to estimate ET over large areas are compared and evaluated. (1) The first one is a variant of the so-called "triangle" method (Jiang et al., 2004), which uses almost exclusively remote sensing data. Vegetation Fraction (Fv) - from the Normalised Difference Vegetation Index (NDVI) - and surface temperature (Ts) were obtained from MODIS products at satellite overpass. The graphical analysis of the Ts-Fv space allows estimating the evaporative fraction (EF), which is then used to derive ET. (2) The second method is the Advection-Aridity (AA) model (Brusaert et al., 1979). This simple approach, which only requires routinely available meteorological data, assumes that a complementary relationship exists between Potential Evapotranspiration (ETpot) and Actual Evapotranspiration (ETa). Although questioned for the lack of scientific basis of the complementary assumption, the AA model is currently used in hydrological applications requiring spatial mapping of ET. (3) The third method relies on the use of a land surface scheme ("JULES" - the Joint UK Land Environment Simulator) which is integrated within the UK Met Office climate model. This approach, based on equations that take into account the different biophysical processes involved in land surface environment, is likely to be the most reliable in theory but in practice it may be limited by the availability of parameters describing the soil and vegetation in a particular area, required to solve the set of equations describing land-atmosphere interactions. The three methods were applied to ET mapping of the Segura River Basin, a semi-arid region of South-Eastern Spain. Results from the case-study are presented and analyzed. Discussion is centred on (i) advantages and limitations of simple ET-retrieval methods vs. complex mechanistic models and (ii) benefits of integrating remote sensing data into ET-models (e.g. data assimilation).

Tanguy, Maliko; Baille, Alain; Taylor, Christopher; Harris, Phil

2010-05-01

202

Comparative study of the osteogenic ability of four different ceramic constructs in an ectopic large animal model.  

PubMed

Tissue-engineered constructs combining bone marrow mesenchymal stem cells with biodegradable osteoconductive scaffolds are very promising for repairing large segmental bone defects. Synchronizing and controlling the balance between scaffold-material resorption and new bone tissue formation are crucial aspects for the success of bone tissue engineering. The purpose of the present study was to determine, and compare, the osteogenic potential of ceramic scaffolds with different resorbability. Four clinically relevant granular biomaterial scaffolds (specifically, Porites coral, Acropora coral, beta-tricalcium phosphate and banked bone) with or without autologous bone marrow stromal cells were implanted in the ectopic, subcutaneous-pouch sheep model. Scaffold material resorption and new bone formation were assessed eight weeks after implantation. New bone formation was only detected when the biomaterial constructs tested contained MSCs. New bone formation was higher in the Porites coral and Acropora coral than in either the beta-tricalcium phosphate or the banked bone constructs; furthermore, there was a direct correlation between scaffold resorption and bone formation. The results of the present study provide evidence that, among the biomaterials tested, coral scaffolds containing MSCs promoted the best new bone formation in the present study. Copyright © 2013 John Wiley & Sons, Ltd. PMID:23784976

Viateau, Véronique; Manassero, Mathieu; Sensébé, Luc; Langonné, Alain; Marchat, David; Logeart-Avramoglou, Delphine; Petite, Hervé; Bensidhoum, Morad

2013-06-20

203

LARGE-SCALE PHYSICAL MODELING OF WATER INJECTION INTO GEOTHERMAL RESERVOIRS AND CORRELATION TO SELF POTENTIAL MEASUREMENTS  

Microsoft Academic Search

Laboratory measurements of electric self potentials resulting from water injection through a known flow path in a 260 mm cube of Nugget sandstone are used to calibrate a new large-scale testing device that simulates the in-situ conditions at an injection point in a geothermal reservoir. Modeled in-situ temperatures were 20 ?C and 150?C, while injection pressures were varied from 1

Jeffrey R. Moore; Steven D. Glaser; H. Frank Morrison

204

Differences in Allergenic Potential of Food Extracts following Oral Exposure in Mice Reflect Differences in Digestibility: Potential Approaches to Safety Assessment  

Microsoft Academic Search

An animal model for food allergy is needed to assess genetically modified food crops for potential allergenicity. The ideal model must produce allergic antibody (IgE) to proteins differentially according to known allergenicity before being used to accurately identify potential allergens among novel proteins. The oral route is the most relevant for exposure to food antigens, and a protein's stability to

Christal C. Bowman; MaryJane K. Selgrade

2008-01-01

205

Potential contribution of MDI to understanding large-scale structures in the corona  

NASA Technical Reports Server (NTRS)

In relation to the understanding of the structure and dynamics of the solar atmosphere which requires realistic coronal magnetic field models, a horizontal current-current sheet (HCCS) coronal model was developed. The model includes large-scale, low altitude, horizontal currents and the effect of thin current sheets in the streamer belt of the field above cusp-type neutral points. The effect of the streamer current sheet on the field below the cusp points is accounted for. In order to suggest what can be anticipated from Michelson Doppler imager (MDI) photospheric magnetic field data calculations of the coronal magnetic field using low spatial resolution data, are presented, and results from the calculations of solar eclipses are compared with solar eclipse images.

Zhao, Xuepu; Hoeksema, J. Todd; Scherrer, Phil H.

1995-01-01

206

Estimating Demand Response Market Potential Among Large Commercialand Industrial Customers:A Scoping Study  

SciTech Connect

Demand response is increasingly recognized as an essentialingredient to well functioning electricity markets. This growingconsensus was formalized in the Energy Policy Act of 2005 (EPACT), whichestablished demand response as an official policy of the U.S. government,and directed states (and their electric utilities) to considerimplementing demand response, with a particular focus on "price-based"mechanisms. The resulting deliberations, along with a variety of stateand regional demand response initiatives, are raising important policyquestions: for example, How much demand response is enough? How much isavailable? From what sources? At what cost? The purpose of this scopingstudy is to examine analytical techniques and data sources to supportdemand response market assessments that can, in turn, answer the secondand third of these questions. We focus on demand response for large(>350 kW), commercial and industrial (C&I) customers, althoughmany of the concepts could equally be applied to similar programs andtariffs for small commercial and residential customers.

Goldman, Charles; Hopper, Nicole; Bharvirkar, Ranjit; Neenan,Bernie; Cappers, Peter

2007-01-01

207

Evidence for a difference in rupture initiation between small and large earthquakes.  

PubMed

The process of earthquake rupture nucleation and propagation has been investigated through laboratory experiments and theoretical modelling, but a limited number of observations exist at the scale of earthquake fault zones. Distinct models have been proposed, and whether the magnitude can be predicted while the rupture is ongoing represents an unsolved question. Here we show that the evolution of P-wave peak displacement with time is informative regarding the early stage of the rupture process and can be used as a proxy for the final size of the rupture. For the analysed earthquake set, we found a rapid initial increase of the peak displacement for small events and a slower growth for large earthquakes. Our results indicate that earthquakes occurring in a region with a large critical slip distance have a greater likelihood of growing into a large rupture than those originating in a region with a smaller slip-weakening distance. PMID:24887597

Colombelli, S; Zollo, A; Festa, G; Picozzi, M

2014-01-01

208

Broadband Photometry of 2012 LZ1: A Large, Dark Potentially Hazardous Asteroid  

NASA Astrophysics Data System (ADS)

2012 LZ1 was discovered on June 10, 2012 by R. McNaught (MPEC 2012-L30). The NEO passed within 0.0364 AU of the Earth on June 14.96 2012 and has been designated as a Potentially Hazardous Asteroid (PHA) by the IAU Minor Planet Center. We obtained 5 nights of time-resolved photometry at the JPL Table Mountain Observatory (TMO) 0.6-m telescope, as summarized in Table 1. Due to a high rate of motion and background star density it was necessary to minimize contamination by creating a running sky background template using adjacent frames and subtracting this template from each R-band frame, as shown in Figure 1.

Hicks, M.; Smythe, W.; Davtyan, T.; Dombroski, D.; Strojia, C.; Teague, S.

2012-07-01

209

Environmental assessment of two different crop systems in terms of biomethane potential production.  

PubMed

The interest in renewable energy sources has gained great importance in Europe due to the need to reduce fossil energy consumption and greenhouse gas emissions, as required by the Renewable Energy Directive (RED) of the European Parliament. The production of energy from energy crops appears to be consistent with RED. The environmental impact related to this kind of energy primarily originates from crop cultivation. This research aimed to evaluate the environmental impact of different crop systems for biomass production: single and double crop. The environmental performances of maize and maize plus wheat were assessed from a life cycle perspective. Two alternative scenarios considering different yields, crop management, and climatic conditions, were also addressed. One normal cubic metre of potential methane was chosen as a functional unit. Methane potential production data were obtained through lab experimental tests. For both of the crop systems, the factors that have the greatest influence on the overall environmental burden are: fertilizer emissions, diesel fuel emissions, diesel fuel production, and pesticide production. Notwithstanding the greater level of methane potential production, the double crop system appears to have the worse environmental performance with respect to its single crop counterpart. This result is due to the bigger quantity of inputs needed for the double crop system. Therefore, the greater amount of biomass (silage) obtained through the double crop system is less than proportional to the environmental burden that results from the bigger quantity of inputs requested for double crop. PMID:23994820

Bacenetti, Jacopo; Fusi, Alessandra; Negri, Marco; Guidetti, Riccardo; Fiala, Marco

2014-01-01

210

Potential fluctuation associated with the energetic-particle-induced geodesic acoustic mode in the Large Helical Device  

NASA Astrophysics Data System (ADS)

Geodesic acoustic modes (GAM) driven by energetic particles are observed in the Large Helical Device (LHD) by a heavy ion beam probe. The GAM localizes near the magnetic axis. It is confirmed that the energetic-particle-induced GAM is accompanied by an electrostatic potential fluctuation and radial electric field fluctuation. The amplitude of the potential fluctuation is several hundred volts, and it is much larger than the potential fluctuation associated with turbulence-induced GAMs observed in the edge region in tokamak plasmas. The energetic-particle-induced GAM modulates the amplitude of the density fluctuation in a high-frequency range. The observed GAM frequency is constant at the predicted GAM frequency in plasmas with reversed magnetic shear. On the other hand, it shifts upwards from the predicted GAM frequency in plasmas with monotonic magnetic shear.

Ido, T.; Shimizu, A.; Nishiura, M.; Nakamura, S.; Kato, S.; Nakano, H.; Yoshimura, Y.; Toi, K.; Ida, K.; Yoshinuma, M.; Satake, S.; Watanabe, F.; Morita, S.; Goto, M.; Itoh, K.; Kubo, S.; Shimozuma, T.; Igami, H.; Takahashi, H.; Yamada, I.; Narihara, K.; LHD Experiment Group

2011-07-01

211

Myoelectric activity along human gastrocnemius medialis: Different spatial distributions of postural and electrically elicited surface potentials  

PubMed Central

It has recently been shown that motor units in human medial gastrocnemius (MG), activated during standing, occupy relatively small territories along the muscle’s longitudinal axis. Such organisation provides potential for different motor tasks to produce differing regional patterns of activity. Here, we investigate whether postural control and nerve electrical stimulation produce equal longitudinal activation patterns in MG. Myoelectric activity, at different proximal–distal locations of MG, was recorded using a linear electrode array. To ensure differences in signal amplitude between channels did not result from local, morphological factors two experimental protocols were completed: (i) quiet standing; (ii) electrical stimulation of the tibial nerve. Averaged, rectified values (ARVs) were calculated for each channel in each condition. The distribution of signals along electrode channels was described using linear regression and differences between protocols at each channel determined as the ratio between mean ARV from standing: stimulation protocols. Ratio values changed systematically across electrode channels in seven (of eight) participants, with larger values in distal channels. The distribution of ARV along MG therefore differed between experimental conditions. Compared to fibres of units activated during MG nerve stimulation, units activated during standing may have a tendency to be more highly represented in the distal muscle portion.

Hodson-Tole, Emma F.; Loram, Ian D.; Vieira, Taian M.M.

2013-01-01

212

Event-related potentials to changes of rhythmic unit: differences between musicians and nonmusicians.  

PubMed

We investigated whether the expected differences between musicians and nonmusicians in their ability to detect a rhythm change were reflected in their event-related potentials (ERPs) and, if reflected, how these ERP differences associated with behavioral indices. Stimuli were three consecutive and equally spaced drum beats followed by a rest period to form a rhythmic unit (RU). By using three different inter-beat periods, three RUs were produced. Combinations of these RUs served as the "target/standard" pairs of an oddball sequence. In four different experiments, we tried two RU-change types each with two levels of detection difficulty. ERPs were recorded from the F3, Fz, F4, Cz and Pz scalp sites of 12 musicians and 12 nonmusicians. RT, hit and false-alarm rates were also measured. The data have shown with high statistical confidence that, associated with the musicians' better detection performance and shorter RTs, their ERP P3 to rhythm changes peaked significantly earlier and was significantly larger compared to nonmusicians. Intergroup ERP differences allowed above 90% correct classification. This study has also showed that not only violations of relatively complex musical regularities, but very simple rhythmic unit alterations could lead to significant P3 differences between musicians and nonmusicians. The high accuracy of the musician/nonmusician classification based only on their P3 data strongly supported the hypothesis that sensory and/or cognitive advantage of musicians in detecting rhythm changes does reflect in their P3. PMID:22311640

Ungan, Pekcan; Berki, Türev; Erbil, Nurhan; Yagcioglu, Suha; Yüksel, Mehmet; Utkucal, Rezzan

2013-01-01

213

Structure of different within-plate magmatic system of large igneous provinces  

Microsoft Academic Search

It is generally accepted that formation of continental large igneous provinces (LIPs) is linked with ascending of mantle superplumes. However, it is not clear yet why and how magmatic systems appeared and functionated. It is known that LIPs are formed by numerous magmatic centers, which imply existence of individual magmatic systems beneath them. Such a situation can be explained by

E. Sharkov

2009-01-01

214

Nucleotide Sequences and Comparison of Two Large Conjugative Plasmids from Different Campylobacter species.  

National Technical Information Service (NTIS)

Two large tetracycline resistance (TcR) plasmids have been completely sequenced, the pTet plasmid (45(question mark)2 kb) from Campylobacter jejuni strain 81-176 and a plasmid pCC31 (44(question mark)7 kb) from Campylobacter coli strain CC31 that was isol...

R. A. Batchelor B. M. Pearson L. M. Friis P. Guerry J. M. Wells

2004-01-01

215

Was Arthur Andersen Different?: An Empirical Examination of Major Accounting Firms' Audits of Large Clients  

Microsoft Academic Search

Enron and other corporate financial scandals focused attention on the accounting industry in general and on Arthur Andersen in particular. Part of the policy response to Enron, the criminal prosecution of Andersen, eliminated one of the few major audit firms capable of auditing many large, public corporations. This article explores whether Andersen’s performance, as measured by frequency of financial restatements,

Theodore Eisenberg; Jonathan R. Macey

2003-01-01

216

Was Arthur Andersen Different? An Empirical Examination of Major Accounting Firm Audits of Large Clients  

Microsoft Academic Search

Enron and other corporate financial scandals focused attention on the accounting industry in general and on Arthur Andersen in particular. Part of the policy response to Enron, the criminal prosecution of Andersen eliminated one of the few major audit firms capable of auditing many large public corporations. This article explores whether Andersen’s performance, as measured by frequency of financial restatements,

Theodore Eisenberg

2004-01-01

217

Large genomic differences between the morphologically indistinguishable diplomonads Spironucleus barkhanus and Spironucleus salmonicida  

Microsoft Academic Search

BACKGROUND: Microbial eukaryotes show large variations in genome structure and content between lineages, indicating extensive flexibility over evolutionary timescales. Here we address the tempo and mode of such changes within diplomonads, flagellated protists with two nuclei found in oxygen-poor environments. Approximately 5,000 expressed sequence tag (EST) sequences were generated from the fish commensal Spironucleus barkhanus and compared to sequences from

Katarina Roxström-Lindquist; Jon Jerlström-Hultqvist; Anders Jørgensen; Karin Troell; Staffan G. Svard; Jan O. Andersson

2010-01-01

218

Reactive power optimization with different objectives in large power systems including HVDC systems and FACTS devices  

Microsoft Academic Search

Present day power systems are growing in size and complexity of operation with inter connections to neighboring systems, introduction of large generating units, EHV 400\\/765 kV AC transmission systems, HVDC systems and more sophisticated control devices such as FACTS. For planning and operational studies, it requires suitable modeling of all components in the power system, as the number of HVDC

D. Thukaram; S. Lakpathi; K. Ravishankar; S. Surendra

2009-01-01

219

Potential nucleation scavenging of smoke particles over large fires: A parametric study  

SciTech Connect

During hypothesized nuclear exchanges massive fires may be ignited and inject large amounts of smoke into the atmosphere. Considerable evidence has been accumulated to suggest that nucleation scavenging where smoke particles serve as cloud condensation nuclei (CCN) may be an important mechanism for incorporating these particles into cloud water. The fraction of smoke particles that act as CCN depends on the cloud environment as well as the affinity of the smoke particles to water. A numerical model of the detailed microphysics of condensation growth on aerosol and cloud drop distributions is employed to produce a parametric study of the dependence of nucleation to a range of conditions. We consider aerosol number concentrations of 10/sup 9//m/sup 3/ to 10/sup 13//m/sup 3/, updraft speeds from 1 to 100 m/s and aerosol particles from fully water soluble to insoluble but wettable. The study provides insight into how well we must characterize smoke particles in order to predict the fraction that act as CCN given the dynamical environment.

Edwards, L.L.; Penner, J.E.

1987-08-01

220

Analysis of Problem of High Power Fiber Laser Combining for Arbitrary Large Optical Phase Differences  

Microsoft Academic Search

Coherent laser beam combining is potentially attractive way to increase the combined beam brightness beyond the limits imposed on single-mode lasers by technological bounds. The active control of every individual laser beam characteristics is more flexible but essentially more complicated in both, necessary equipment and service. Passive phase locking is an attractive alternative, since it does not need external management

A. P. Napartovich; N. N. Elkin; D. V. Vysotsky

2010-01-01

221

Structural optimization of Ag-Pd clusters based on different potential parameterizations  

NASA Astrophysics Data System (ADS)

The putative stable structures of bimetallic Ag-Pd clusters are investigated. Gupta potential is applied to describe the interatomic interactions in Ag-Pd clusters. Experimental-fitted parameters and density-functional-theory (DFT)-fitted parameters are used to determine the lowest energy structures. Global optimization of Ag mPd n ( m + n = 15) and Ag 3mPd 38-3m ( m = 1-12) clusters is performed using adaptive immune optimization algorithm (AIOA). The growth rules of Ag-Pd clusters for both sets of parameterizations are studied, and the differences of structures and excess energies are compared. With the order parameters adopted to show the atomic distribution in the clusters, it is shown that for both parameterized clusters silver atoms have strong tendencies towards segregating at the surface of the structures. However, for both potentials, the atomic distribution of Ag and Pd atoms in Ag-Pd clusters is different because of the geometrical and symmetrical difference.

Wu, Xia; Wu, Yiping; Kai, Xiaoming; Wu, Genhua; Chen, Youcun

2011-11-01

222

The multigrid POTFIT (MGPF) method: Grid representations of potentials for quantum dynamics of large systems  

NASA Astrophysics Data System (ADS)

In this article, a new method, multigrid POTFIT (MGPF), is presented. MGPF is a grid-based algorithm which transforms a general potential energy surface into product form, that is, a sum of products of one-dimensional functions. This form is necessary to profit from the computationally advantageous multiconfiguration time-dependent Hartree method for quantum dynamics. MGPF circumvents the dimensionality related issues present in POTFIT [A. Jäckle and H.-D. Meyer, J. Chem. Phys. 104, 7974 (1996)], allowing quantum dynamical studies of systems up to about 12 dimensions. MGPF requires the definition of a fine grid and a coarse grid, the latter being a subset of the former. The MGPF approximation relies on a series of underlying POTFIT calculations on grids which are smaller than the fine one and larger than or equal to the coarse one. This aspect makes MGPF a bit less accurate than POTFIT but orders of magnitude faster and orders of magnitude less memory demanding than POTFIT. Moreover, like POTFIT, MGPF is variational and provides an efficient error control.

Peláez, Daniel; Meyer, Hans-Dieter

2013-01-01

223

Cross-polar cap potential difference, auroral electrojet indices, and solar wind parameters  

SciTech Connect

The cross-polar cap potential difference {Phi} (KRM) is estimated from ground magnetic perturbation data through the magnetometer inversion method of Kamide, Richmond, and Matsushita (FRM), combined with an empirical ionospheric conductance distribution estimated from the DMSP X ray image data. A significant correlation is found between {Phi} (KRM) and the AE(12) index. {Phi} (KRM) is then compared with the potential difference estimated from a more direct method of the satellite electric field measurements and also with {Phi}(IMF) is found to be linearly correlated with {Phi} (IMF) based on solar wind parameters. {Phi} IMF is found to be linearly correlated with {Phi}(KRM), as {Phi}(IMF) = 29.8 + 0.999 {Phi} (KRM), with the highest correlation obtained for a 40-min lag in the interplanetary magnetic field (IMF). Note that {Phi}(IMF) is systematically larger than {Phi} (KRM) by 30 kV, suggesting the possibility that the theoretical method overestimates the cross-polar cap potential difference. During steady southward IMF periods were steady {Phi} (IMF) variations are expected, significant fluctuations in calculated {Phi} (KRM) values are obtained. Since the decrease in {Phi} (KRM) is closely associated with enhancements in auroral particle precipitation during these periods, a highly correlative relation between {Phi} (IMF) and {Phi} (KRM) cannot be deduced unless the phases of substorms are taken into account. The overall high correlation between them, however, supports the view expressed by Wolf et al. (1986) that directly driven processes are more important than unloading processes during disturbed periods.

Ahn, B.H. (Kyungpook National Univ., Taegu (Korea) Univ. of Colorado, Boulder (United States)); Kamide, Y. (Kyoto Sangyo Univ., (Japan)); Kroehl, H.W.; Gorney, D.J. (Aerospace Corp., Los Angeles, CA (United States))

1992-02-01

224

A conservative finite difference algorithm for the unsteady transonic potential equation in generalized coordinates  

NASA Technical Reports Server (NTRS)

An implicit, approximate-factorization, finite-difference algorithm has been developed for the computation of unsteady, inviscid transonic flows in two and three dimensions. The computer program solves the full-potential equation in generalized coordinates in conservation-law form in order to properly capture shock-wave position and speed. A body-fitted coordinate system is employed for the simple and accurate treatment of boundary conditions on the body surface. The time-accurate algorithm is modified to a conventional ADI relaxation scheme for steady-state computations. Results from two- and three-dimensional steady and two-dimensional unsteady calculations are compared with existing methods.

Bridgeman, J. O.; Steger, J. L.; Caradonna, F. X.

1982-01-01

225

An Aspergillus chitosanase with potential for large-scale preparation of chitosan oligosaccharides.  

PubMed

A chitosan-degrading fungus, designated Aspergillus sp. Y2K, was isolated from soil. The micro-organism was used for producing chitosanase (EC 3.2.1.132) in a minimal medium containing chitosan as the sole carbon source. The induced chitosanase was purified to homogeneity from the culture filtrate by concentration and cationic SP-Sepharose chromatography. The purified enzyme is a monomer with an estimated molecular mass of 25 kDa by SDS/PAGE and of 22 kDa by gel-filtration chromatography. pI, optimum pH and optimum temperature values were 8.4, 6.5 and 65-70 degrees C, respectively. The chitosanase is stable in the pH range from 4 to 7.5 at 55 degrees C. Higher deacetylated chitosan is a better substrate. Chitin, xylan, 6-O-sulphated chitosan and O-carboxymethyl chitin were indigestible by the purified enzyme. By endo-splitting activity, the chitosanase hydrolysed chitosan to form chitosan oligomers with chitotriose, chitotetraose and chitopentaose as the major products. The enzyme hydrolyses chitohexaose to form chitotriose, while the chitopentaose and shorter oligomers remain intact. The N-terminal amino acid sequence of the enzyme was determined as YNLPNNLKQIYDDHK, which provides useful information for further gene cloning of this enzyme. A 275 g-scale hydrolysis of chitosan was performed. The product distribution was virtually identical to that of the small-scale reaction. Owing to the simple purification process and high stability of the enzyme, it is potentially valuable for industrial applications. PMID:11115392

Cheng, C Y; Li, Y K

2000-12-01

226

Sex Differences in Autism Spectrum Disorder: Evidence from a Large Sample of Children and Adolescents  

ERIC Educational Resources Information Center

Sex differences have been found amongst toddlers and young children with autism spectrum disorder (ASD). We investigated the presence and stability of these ASD sex differences throughout childhood and adolescence. Participants (N = 325, 52 females; aged 3-18 years) consecutively received an ASD diagnosis at a clinic for assessing high-functioning…

Mandy, William; Chilvers, Rebecca; Chowdhury, Uttom; Salter, Gemma; Seigal, Anna; Skuse, David

2012-01-01

227

HPV16 E6 natural variants exhibit different activities in functional assays relevant to the carcinogenic potential of E6.  

PubMed

Genetic studies have revealed natural amino acid variations within the human papillomavirus (HPV) type 16 E6 oncoprotein. To address the functional significance of E6 polymorphisms, 10 HPV16 E6 variants isolated from cervical lesions of Swedish women were evaluated for their activities in different in vitro and in vivo assays relevant to the carcinogenic potential of E6. Small differences between E6 prototype and variants, and among variants, were observed in transient expression assays that assessed p53 degradation, Bax degradation, and inhibition of p53 transactivation. More variable levels of activities were exhibited by the E6 proteins in assays that evaluated binding to the E6-binding protein (E6BP) or the human discs large protein (hDlg). The E6 prototype expressed moderate to high activity in the above assays. The L83V polymorphism, previously associated with risk for cancer progression in some populations, expressed similar levels of activity as that of the E6 prototype in most functional assays. On the other hand, L83V displayed more efficient degradation of Bax and binding to E6BP, but lower binding to hDlg. Results of this study indicate that naturally occurring amino acid variations in HPV16 E6 can alter activities of the protein important for its carcinogenic potential. PMID:16519914

Lichtig, Hava; Algrisi, Meirav; Botzer, Liat Edri; Abadi, Tal; Verbitzky, Yulia; Jackman, Anna; Tommasino, Massimo; Zehbe, Ingeborg; Sherman, Levana

2006-06-20

228

Plant community response to loss of large herbivores differs between North American and South African savanna grasslands.  

PubMed

Herbivory and fire shape plant community structure in grass-dominated ecosystems, but these disturbance regimes are being altered around the world. To assess the consequences of such alterations, we excluded large herbivores for seven years from mesic savanna grasslands sites burned at different frequencies in North America (Konza Prairie Biological Station, Kansas, USA) and South Africa (Kruger National Park). We hypothesized that the removal of a single grass-feeding herbivore from Konza would decrease plant community richness and shift community composition due to increased dominance by grasses. Similarly, we expected grass dominance to increase at Kruger when removing large herbivores, but because large herbivores are more diverse, targeting both grasses and forbs, at this study site, the changes due to herbivore removal would be muted. After seven years of large-herbivore exclusion, richness strongly decreased and community composition changed at Konza, whereas little change was evident at Kruger. We found that this divergence in response was largely due to differences in the traits and numbers of dominant grasses between the study sites rather than the predicted differences in herbivore assemblages. Thus, the diversity of large herbivores lost may be less important in determining plant community dynamics than the functional traits of the grasses that dominate mesic, disturbance-maintained savanna grasslands. PMID:24933802

Koerner, Sally E; Burkepile, Deron E; Fynn, Richard W S; Burns, Catherine E; Eby, Stephanie; Govender, Navashni; Hagenah, Nicole; Matchett, Katherine J; Thompson, Dave I; Wilcox, Kevin R; Collins, Scott L; Kirkman, Kevin P; Knapp, Alan K; Smith, Melinda D

2014-04-01

229

Estimating sugarcane yield potential using an in-season determination of normalized difference vegetative index.  

PubMed

Estimating crop yield using remote sensing techniques has proven to be successful. However, sugarcane possesses unique characteristics; such as, a multi-year cropping cycle and plant height-limiting for midseason fertilizer application timing. Our study objective was to determine if sugarcane yield potential could be estimated using an in-season estimation of normalized difference vegetative index (NDVI). Sensor readings were taken using the GreenSeeker® handheld sensor from 2008 to 2011 in St. Gabriel and Jeanerette, LA, USA. In-season estimates of yield (INSEY) values were calculated by dividing NDVI by thermal variables. Optimum timing for estimating sugarcane yield was between 601-750 GDD. In-season estimated yield values improved the yield potential (YP) model compared to using NDVI. Generally, INSEY value showed a positive exponential relationship with yield (r(2) values 0.48 and 0.42 for cane tonnage and sugar yield, respectively). When models were separated based on canopy structure there was an increase the strength of the relationship for the erectophile varieties (r(2) 0.53 and 0.47 for cane tonnage and sugar yield, respectively); however, the model for planophile varieties weakened slightly. Results of this study indicate using an INSEY value for predicting sugarcane yield shows potential of being a valuable management tool for sugarcane producers in Louisiana. PMID:22969359

Lofton, Josh; Tubana, Brenda S; Kanke, Yumiko; Teboh, Jasper; Viator, Howard; Dalen, Marilyn

2012-01-01

230

Comparing large scale CCS deployment potential in the USA and China: a detailed analysis based on country-specific CO2 transport & storage cost curves  

SciTech Connect

The United States and China are the two largest emitters of greenhouse gases in the world and their projected continued growth and reliance on fossil fuels, especially coal, make them strong candidates for CCS. Previous work has revealed that both nations have over 1600 large electric utility and other industrial point CO2 sources as well as very large CO2 storage resources on the order of 2,000 billion metric tons (Gt) of onshore storage capacity. In each case, the vast majority of this capacity is found in deep saline formations. In both the USA and China, candidate storage reservoirs are likely to be accessible by most sources with over 80% of these large industrial CO2 sources having a CO2 storage option within just 80 km. This suggests a strong potential for CCS deployment as a meaningful option to efforts to reduce CO2 emissions from these large, vibrant economies. However, while the USA and China possess many similarities with regards to the potential value that CCS might provide, including the range of costs at which CCS may be available to most large CO2 sources in each nation, there are a number of more subtle differences that may help us to understand the ways in which CCS deployment may differ between these two countries in order for the USA and China to work together - and in step with the rest of the world - to most efficiently reduce greenhouse gas emissions. This paper details the first ever analysis of CCS deployment costs in these two countries based on methodologically comparable CO2 source and sink inventories, economic analysis, geospatial source-sink matching and cost curve modeling. This type of analysis provides a valuable insight into the degree to which early and sustained opportunities for climate change mitigation via commercial-scale CCS are available to the two countries, and could facilitate greater collaboration in areas where those opportunities overlap.

Dahowski, Robert T.; Davidson, Casie L.; Dooley, James J.

2011-04-18

231

Differences in Relative Importance of the Factors That Determine Profit in Small and Large Businesses.  

National Technical Information Service (NTIS)

The profit forecasts using FINSTAT and COMPUSTAT data show that efficiency measures most significantly predict small businesses' return on assets, while leverage and capital structure measures are most important for larger businesses. These differences ar...

D. Rothenberg

1987-01-01

232

Cross-national price differences for pharmaceuticals: how large, and why?  

Microsoft Academic Search

Bilateral drug price and quantity indexes, based on comprehensive data for seven countries (US, Canada, France, Germany, Italy, Japan and the UK), refute the conventional wisdom that US drug prices are much higher than elsewhere, for Laspeyres (US-weighted) indexes. Previous drug-price comparisons are biased by unrepresentative samples and unweighted indexes. Quasi-hedonic regression shows that cross-national price differences reflect differences in

Patricia M. Danzon; Li-Wei Chao

2000-01-01

233

Apollo 14 regolith breccias - Different glass populations and their potential for charting space time variations  

NASA Technical Reports Server (NTRS)

Apollo 14 regolith breccias (14313, 14307, 14301, 14049, 14047) have been found to have different populations of nonagglutinitic, mare-derived glasses. These variations appear to not only reflect different source regoliths but also different closure ages for these breccias. Based upon these different glass populations, 14301 is inferred to have a closure age sometime during the epoch of mare volcanism. All of the other four breccias were formed after the termination of mare volcanism with a possible age sequence from old to young of the following: 14307, 14313, 14049, 14047. Due to the relative simplicity of acquiring high-quality chemical data on large numbers of glasses by electron microprobe, mare glass populations allow: (1) classification of regolith breccias with respect to provenance and (2) estimation of their relative and absolute closure ages. The determination of (Ar-40)-(Ar-39) ages on individual glass spherules within breccias using the laser probe should in the future prove to be a promising extension of the present study.

Delano, John W.

1988-01-01

234

Differing ulcerogenic potential of dihydroxy and trihydroxy bile acids in canine gastric mucosa.  

PubMed

Although recent clinical reports suggest that greater than normal amounts of dihydroxy secondary bile acids appear in the gastric content of patients with postoperative alkaline reflux gastritis, the pathophysiologic significance of these observations is unclear. We addressed this problem by usiong chambered ex vivo wedges of proximal canine gastric wall. The effects of 1 and 2 mM concentrations of the dihydroxy secondary bile acid, taurodeoxycholic, were compared with those of its parent trihydroxy primary bile acid, taurocholic. The parameters of mucosal function evaluated included the net flux of hydrogen ion, the transmural electrical potential difference, mucosal blood flow determined by radiolabeled microsphere embolization, and the severity of mucosal damage induced in mucosa rendered ischemic by wedge-specific intra-arterial low-dose vasopressin infusin. The results indicate that at each concentration in both ischemic and nonischemic mucosa the dihydroxy secondary bile acid induced a greater depression in potential difference, a more profound increase in mucosal permeability to hydrogen ion, and in ischemic mucosa a more severe degree of gross mucosal damage than did the trihydroxy primary bile acid. These effects may be related to a greater lipid solubility and consequent capacity to disrupt cell membranes. PMID:7466624

Ritchie, W P; Felger, T S

1981-03-01

235

Repetition and brain potentials when recognizing natural scenes: task and emotion differences.  

PubMed

Repetition has long been known to facilitate memory performance, but its effects on event-related potentials (ERPs), measured as an index of recognition memory, are less well characterized. In Experiment 1, effects of both massed and distributed repetition on old-new ERPs were assessed during an immediate recognition test that followed incidental encoding of natural scenes that also varied in emotionality. Distributed repetition at encoding enhanced both memory performance and the amplitude of an old-new ERP difference over centro-parietal sensors. To assess whether these repetition effects reflect encoding or retrieval differences, the recognition task was replaced with passive viewing of old and new pictures in Experiment 2. In the absence of an explicit recognition task, ERPs were completely unaffected by repetition at encoding, and only emotional pictures prompted a modestly enhanced old-new difference. Taken together, the data suggest that repetition facilitates retrieval processes and that, in the absence of an explicit recognition task, differences in old-new ERPs are only apparent for affective cues. PMID:22842817

Ferrari, Vera; Bradley, Margaret M; Codispoti, Maurizio; Karlsson, Marie; Lang, Peter J

2013-12-01

236

Large-scale, high-resolution electrophysiological imaging of field potentials in brain slices with microelectronic multielectrode arrays.  

PubMed

Multielectrode arrays (MEAs) are extensively used for electrophysiological studies on brain slices, but the spatial resolution and field of recording of conventional arrays are limited by the low number of electrodes available. Here, we present a large-scale array recording simultaneously from 4096 electrodes used to study propagating spontaneous and evoked network activity in acute murine cortico-hippocampal brain slices at unprecedented spatial and temporal resolution. We demonstrate that multiple chemically induced epileptiform episodes in the mouse cortex and hippocampus can be classified according to their spatio-temporal dynamics. Additionally, the large-scale and high-density features of our recording system enable the topological localization and quantification of the effects of antiepileptic drugs in local neuronal microcircuits, based on the distinct field potential propagation patterns. This novel high-resolution approach paves the way to detailed electrophysiological studies in brain circuits spanning spatial scales from single neurons up to the entire slice network. PMID:23162432

Ferrea, E; Maccione, A; Medrihan, L; Nieus, T; Ghezzi, D; Baldelli, P; Benfenati, F; Berdondini, L

2012-01-01

237

Hydrogen atom with a Yukawa potential: Perturbation theory and continued-fractions--Pade approximants at large order  

SciTech Connect

A simple power-series method is developed to calculate to large order the Rayleigh-Schroedinger perturbation expansions for energy levels of a hydrogen atom with a Yukawa-type screened Coulomb potential. Perturbation series for the 1s, 2s, and 2p levels, shown not to be of the Stieltjes type, are calculated to 100th order. Nevertheless, the poles of the Pade approximants to these series generally avoid the region of the positive real axis 0 < lambda < lambda(, where lambda( represents the coupling constant threshold. As a result, the Pade sums afford accurate approximations to E(lambda) in this domain. The continued-fraction representations to these perturbation series have been accurately calculated to large (100th) order and demonstrate a curious ''quasioscillatory,'' but non-Stieltjes, behavior. Accurate values of E(lambda) as well as lambda( for the 1s, 2s, and 2p levels are reported.

Vrscay, E.R.

1986-02-01

238

A Large Gene Cluster Encoding Several Magnetosome Proteins Is Conserved in Different Species of Magnetotactic Bacteria  

Microsoft Academic Search

In magnetotactic bacteria, a number of specific proteins are associated with the magnetosome membrane (MM) and may have a crucial role in magnetite biomineralization. We have cloned and sequenced the genes of several of these polypeptides in the magnetotactic bacterium Magnetospirillum gryphiswaldense that could be assigned to two different genomic regions. Except for mamA, none of these genes have been

KAREN GRUNBERG; CATHRIN WAWER; BRADLEY M. TEBO; DIRK SCHULER

2001-01-01

239

[Temperature compensation strategy and implementation for photoelectric modulation interferometer with large optical path difference].  

PubMed

For temperature drift in hypervelocity photoelectric modulation interferometer, a control model of temperature compensation is presented including voltage and phase compensation. First, according to the similar and modeling theory, an equivalent circuit model of mechanical properties of hypervelocity photoelectric modulation interferometer was established, the impact of temperature drift on its resonance frequency was analyzed, a mathematical model was set up, which contains drive voltage, frequency and resonance frequency, and the control method was determined for high optical path difference to get steady. Then, a digital method including voltage and phase compensation is given for optical path difference deviation control, which merges the DPLL and program of voltage and phase compensation. Finally, the control method was tested through experiment system. A test between drive control system including voltage and phase compensation and traditional drive control system was executed, using a laser doppler vibrometer to record the amount of change in optical path difference within 3 hours. Results show that the optical path difference deviation caused by temperature drift in long term is reduced by about 50%. PMID:23905367

Wang, Yan-Chao; Wang, Zhi-Bin; Zhang, Ji-Long; Chen, You-Hua

2013-05-01

240

Who Gets Market Supplements? Gender Differences within a Large Canadian University  

ERIC Educational Resources Information Center

This study examines the gender pay gap among university faculty by analyzing gender differences in one component of faculty members' salaries--"market premiums." The data were collected during the Fall of 2002 using a survey of faculty at a single Canadian research university. Correspondence analysis and logistic regression analysis were performed…

Doucet, Christine; Durand, Claire; Smith, Michael

2008-01-01

241

Biomechanical analysis of large segmental bone repair with different fixation apparatuses  

Microsoft Academic Search

Efficient mechanical tools for the structural optimization of variable fixation apparatuses are presented in this study. The defect model prepared from 24 ulna-radius specimens are fixated respectively and randomly with new designed internal fixation panel, AO 4 holes panel, one-side external fixation bracket of Zimmer and negative comparison group, different experimental data are analyzed. Through experimental results, it can be

Zhijian Su; Zhongzhong Chen; Zheng Wei; Zhenhong Xia

2010-01-01

242

Motor unit potential morphology differences in individuals with non-specific arm pain and lateral epicondylitis  

PubMed Central

Background The pathophysiology of non-specific arm pain (NSAP) is unclear and the diagnosis is made by excluding other specific upper limb pathologies, such as lateral epicondylitis or cervical radiculopathy. The purpose of this study was to determine: (i) if the quantitative parameters related to motor unit potential morphology and/or motor unit firing patterns derived from electromyographic (EMG) signals detected from an affected muscle of patients with NSAP are different from those detected in the same muscle of individuals with lateral epicondylitis (LE) and/or control subjects and (ii) if the quantitative EMG parameters suggest that the underlying pathophysiology in NSAP is either myopathic or neuropathic in nature. Methods Sixteen subjects with NSAP, 11 subjects with LE, eight subjects deemed to be at-risk for developing a repetitive strain injury, and 37 control subjects participated. A quantitative electromyography evaluation was completed using decomposition-based quantitative electromyography (DQEMG). Needle- and surface-detected EMG signals were collected during low-level isometric contractions of the extensor carpi radialis brevis (ECRB) muscle. DQEMG was used to extract needle-detected motor unit potential trains (MUPTs), and needle-detected motor unit potential (MUP) and surface detected motor unit potential (SMUP) morphology and motor unit (MU) firing rates were compared among the four groups using one-way analysis of variance (ANOVA). Post hoc analyses were performed using Tukey's pairwise comparisons. Results Significant group differences were found for all MUP variables and for MU firing rate (p < 0.006). The post-hoc analyses revealed that patients with NSAP had smaller MUP amplitude and SMUP amplitude and area compared to the control and LE groups (p < 0.006). MUP duration and AAR values were significantly larger in the NSAP, LE and at-risk groups compared to the control group (p < 0.006); while MUP amplitude, duration and AAR values were smaller in the NSAP compared to the LE group. SMUP duration was significantly shorter in the NSAP group compared to the control group (p < 0.006). NSAP, LE and at-risk subjects had lower mean MU firing rates than the control subjects (p < 0.006). Conclusion The size-related parameters suggest that the NSAP group had significantly smaller MUPs and SMUPs than the control and LE subjects. Smaller MUPs and SMUPs may be indicative of muscle fiber atrophy and/or loss. A prospective study is needed to confirm any causal relationship between smaller MUPs and SMUPs and NSAP as found in this work.

Calder, Kristina M; Stashuk, Daniel W; McLean, Linda

2008-01-01

243

Potential of infrared spectroscopy in combination with extended canonical variate analysis for identifying different paper types  

NASA Astrophysics Data System (ADS)

The increasing use of secondary fiber in papermaking has led to the production of paper containing a wide range of contaminants. Wastepaper mills need to develop quality control methods for evaluating the incoming wastepaper stock as well as testing the specifications of the final product. The goal of this work is to present a fast and successful methodology for identifying different paper types. In this way, undesirable paper types can be refused, thus improving the runnability of the paper machine and the quality of the paper manufactured. In this work we examine various types of paper using information obtained by an appropriate chemometric treatment of infrared spectral data. For this purpose, we studied a large number of paper sheets of three different types (namely coated, offset and cast-coated) supplied by several paper manufacturers. We recorded Fourier transform infrared (FTIR) spectra with the aid of an attenuated total reflectance (ATR) module and near-infrared (NIR) reflectance spectra by means of fiber optics. Both techniques proved expeditious and required no sample pretreatment. The primary objective of this work was to develop a methodology for the accurate identification of samples of different paper types. For this purpose, we used the chemometric discrimination technique extended canonical variate analysis (ECVA) in combination with the k nearest neighbor (kNN) method to classify samples in the prediction set. Use of the NIR and FTIR techniques under these conditions allowed paper types to be identified with 100% success in prediction samples.

Riba, Jordi-Roger; Canals, Trini; Cantero, Rosa; Iturriaga, Hortensia

2011-02-01

244

Prediction of in vivo drug clearance from in vitro data. II: potential inter-ethnic differences.  

PubMed

Potential differences in drug clearance between Japanese and Caucasians were investigated by integrating data on demography, liver size, the abundance of the major cytochromes P450 and in vitro metabolic parameters. Eleven drugs (alprazolam, caffeine, chlorzoxazone, cyclosporine, midazolam, omeprazole, sildenafil, tolbutamide, triazolam, S-warfarin and zolpidem) fulfilled the entry criteria of the study (i.e. the necessary in vitro metabolism data were available and clearance values had been reported both in Caucasians and Japanese). Values of relevant biological variables were obtained from the literature, and clearance predictions were made using the Simcyp Population-Based ADME Simulator. The ratios of observed oral clearance (CLp.o.) values in Caucasians compared with Japanese ranged from 0.6 to 2.8 (integrating data from 82 sources). The CLp.o. values for alprazolam, caffeine and zolpidem were not statistically different between Caucasian and Japanese (p>0.05), whereas those for chorzoxazone, cyclosporine, omeprazole, tolbutamide and triazolam were higher in Caucasians (p<0.05), and those for midazolam, sildenafil and S-warfarin were higher in Japanese (p<0.05). CLp.o. values, predicted from in vitro data, were within 3-fold of observed in vivo values for seven of the 11 drugs in Japanese. Values for the predicted ratios ranged from 1.6 to 4.9. The predicted ratios were not significantly different from observed ratios for cyclosporine, omeprazole, tolbutamide and triazolam. Only partial success in predicting ethnic differences in clearance indicates the need for larger and more reliable databases on relevant variables. With such information, in silico predictions might be used with more confidence to decrease the need for repeating pharmacokinetic studies in different ethnic groups. PMID:16865818

Inoue, S; Howgate, E M; Rowland-Yeo, K; Shimada, T; Yamazaki, H; Tucker, G T; Rostami-Hodjegan, A

2006-06-01

245

Do males and females differ in the feeding of large and small siblings? An experiment with the bluethroat  

Microsoft Academic Search

Males and females have been reported to differ in their feeding of large and small siblings in several species of birds.\\u000a According to recent hypotheses, this phenomenon may be related to a sexual conflict over avian hatching patterns. We designed\\u000a an experiment to test for the existence of such a sex difference by manipulating nestling size hierarchies of the bluethroat

Per T. Smiseth; Trond Amundsen; Lars T. T. Hansen

1998-01-01

246

Differences in human evoked potentials related to olfactory or trigeminal chemosensory activation.  

PubMed

The aim of the present study was to determine, whether there are differences in the topographical distribution of chemosensory evoked potentials (CSEPs) due to stimulation with different odorous substances. The odorants used in the study which mainly excited the olfactory nerve were vanillin and acetaldehyde; those which additionally excited the trigeminal nerve were sulphur dioxide and ammonia. Twelve subjects participated in the study. The subjects separately estimated the intensity of the odorous and of the painful/pricking sensation caused by the stimuli, and described the odorous qualities in their own words. CSEPs were recorded from 7 positions. After stimulation with "olfactory" substances maximum CSEP amplitudes were recorded at parieto-central sites, and after stimulation with "trigeminal" substances maximum amplitudes were obtained at the vertex. Following stimulation with ammonia and sulphur dioxide amplitudes were largest contralateral to the stimulated nostril. In contrast, little difference in CSEP amplitudes was observed between hemispheres after stimulation with vanillin or acetaldehyde. Thus, the topographical distribution of CSEP amplitudes may provide information with regard to the sensory system (olfactory or trigeminal) activated by the presentation of an odorous stimulus. PMID:1370406

Hummel, T; Kobal, G

1992-01-01

247

Interannual variation in climate-potential net primary productivity relationships in differing ecosystems of California  

SciTech Connect

The seasonality and interannual variation in potential net primary production (NPP) were examined in differing vegetation types in California over three years of contrasting precipitation using co-registered maps of climate, vegetation, and 1km biweekly NDVI derived from high resolution satellite AVHRR data. Differences in seasonality of the vegetation types (annual grassland, chamise chaparral, deciduous oak woodland, and evergreen oak) were clearly evident and corresponded well to patterns observed in field studies. In years and locations having high precipitation the annual peak in NDVI occurred later in all vegetation classes. The annual sum of biweekly NDVI was correlated with annual precipitation in all vegetation types, although the slopes and intercepts of the regressions differed among types. Annual grassland showed the largest increase in sumNDVI per unit increase in total precipitation and most of the variation in grassland sumNDVI was explained by variation in autumn precipitation. In general the ratio of sumNDVI to annual precipitation was dependent on the temporal distribution of precipitation with respect to the long-term average pattern. Published relationships between precipitation and NPP were used to develop equations relating annual NDVI sum to NPP.

Koch, G.W.; Randerson, J.T. (Stanford Univ. Carnegie Institution of Plant Biology, CA (United States))

1994-06-01

248

Compressive behaviour of axially loaded spruce wood under large deformations at different strain rates  

Microsoft Academic Search

Impact limiting components of packages for the transport of radioactive materials are often designed as wood filled steel\\u000a constructions. Wood absorbs major part of the impact energy in order to minimise the impact load acting upon the containment.\\u000a Dynamic impact experiments with wood filled impact limiters showed different crushing mechanisms for axially loaded wood depending\\u000a on their lateral constraint. Tests

Martin Neumann; Jürgen Herter; Bernhard O. Droste; Sylvius Hartwig

249

Modeling the large-scale water balance impact of different irrigation systems  

Microsoft Academic Search

(1) In this study, two parameterizations for different irrigation techniques have been implemented in a regional climate model. These implementations allow for a comparative study of water use and land-atmosphere interactions associated with traditional flood irrigation—a widespread but highly water-inefficient practice—and water-conserving drip irrigation. Both parameterizations yield realistic results for coupled climate simulations, and do so without the need to

J. P. Evans; B. F. Zaitchik

2008-01-01

250

Modeling the large-scale water balance impact of different irrigation systems  

Microsoft Academic Search

In this study, two parameterizations for different irrigation techniques have been implemented in a regional climate model. These implementations allow for a comparative study of water use and land–atmosphere interactions associated with traditional flood irrigation—a widespread but highly water-inefficient practice—and water-conserving drip irrigation. Both parameterizations yield realistic results for coupled climate simulations, and do so without the need to reproduce

J. P. Evans; B. F. Zaitchik

2008-01-01

251

Comparison of Earth-tide parameters over a large latitude difference  

Microsoft Academic Search

Gravity Earth-tide observations at the station of Thessaloniki with a LaCoste-Romberg gravity meter equipped with electrostatic feedback were analysed in order to obtain accurate amplitude and phase-difference tidal parameters. The observations cover a total number of 162.5 days. The frequency transfer-function of our measuring system was defined using the step-response procedure. The Tamura tidal development was used as normal tidal

D. Arabelos

2002-01-01

252

Wavelet analysis of corneal endothelial electrical potential difference reveals cyclic operation of the secretory mechanism.  

PubMed

The corneal endothelium is a fluid-transporting epithelium. As other similar tissues, it displays an electrical potential of ~1 mV (aqueous side negative) across the entire layer [transendothelial potential difference (TEPD)]. It appears that this electrical potential is mainly the result of the transport of anions across the cell layer (from stroma to aqueous). There is substantial evidence that the TEPD is related linearly to fluid transport; hence, under proper conditions, its measure could serve as a measure of fluid transport. Furthermore, the TEPD is not steady; instead, it displays a spectrum of frequency components (0-15 Hz) recognized recently using Fourier transforms. Such frequency components appear due to charge-separating (electrogenic) processes mediated by epithelial plasma membrane proteins (both ionic channels and ionic cotransporters). In particular, the endothelial TEPD oscillations of the highest amplitude (1-2 Hz) were linked to the operation of so-called sodium bicarbonate cotransporters. However, no time localization of that activity could be obtained with the Fourier methodology utilized. For that reason we now characterize the TEPD using wavelet analysis with the aim to localize in time the variations in TEPD. We find that the mentioned high-amplitude oscillatory components of the TEPD appear cyclically during the several hours that an endothelial preparation survives in vitro. They have a period of 4.6 ± 0.4 s on average (n=4). The wavelet power value at the peak of such oscillations is 1.5 ± 0.1 mV(2) Hz on average (n = 4), and is remarkably narrow in its distribution. PMID:22060438

Cacace, V I; Montalbetti, N; Kusnier, C; Gomez, M P; Fischbarg, J

2011-09-01

253

Wavelet analysis of corneal endothelial electrical potential difference reveals cyclic operation of the secretory mechanism  

NASA Astrophysics Data System (ADS)

The corneal endothelium is a fluid-transporting epithelium. As other similar tissues, it displays an electrical potential of ˜1 mV (aqueous side negative) across the entire layer [transendothelial potential difference (TEPD)]. It appears that this electrical potential is mainly the result of the transport of anions across the cell layer (from stroma to aqueous). There is substantial evidence that the TEPD is related linearly to fluid transport; hence, under proper conditions, its measure could serve as a measure of fluid transport. Furthermore, the TEPD is not steady; instead, it displays a spectrum of frequency components (0-15 Hz) recognized recently using Fourier transforms. Such frequency components appear due to charge-separating (electrogenic) processes mediated by epithelial plasma membrane proteins (both ionic channels and ionic cotransporters). In particular, the endothelial TEPD oscillations of the highest amplitude (1-2 Hz) were linked to the operation of so-called sodium bicarbonate cotransporters. However, no time localization of that activity could be obtained with the Fourier methodology utilized. For that reason we now characterize the TEPD using wavelet analysis with the aim to localize in time the variations in TEPD. We find that the mentioned high-amplitude oscillatory components of the TEPD appear cyclically during the several hours that an endothelial preparation survives in vitro. They have a period of 4.6 ± 0.4 s on average (n=4). The wavelet power value at the peak of such oscillations is 1.5 ± 0.1 mV2 Hz on average (n = 4), and is remarkably narrow in its distribution.

Cacace, V. I.; Montalbetti, N.; Kusnier, C.; Gomez, M. P.; Fischbarg, J.

2011-09-01

254

An Application of the Difference Potentials Method to Solving External Problems in CFD  

NASA Technical Reports Server (NTRS)

Numerical solution of infinite-domain boundary-value problems requires some special techniques that would make the problem available for treatment on the computer. Indeed, the problem must be discretized in a way that the computer operates with only finite amount of information. Therefore, the original infinite-domain formulation must be altered and/or augmented so that on one hand the solution is not changed (or changed slightly) and on the other hand the finite discrete formulation becomes available. One widely used approach to constructing such discretizations consists of truncating the unbounded original domain and then setting the artificial boundary conditions (ABC's) at the newly formed external boundary. The role of the ABC's is to close the truncated problem and at the same time to ensure that the solution found inside the finite computational domain would be maximally close to (in the ideal case, exactly the same as) the corresponding fragment of the original infinite-domain solution. Let us emphasize that the proper treatment of artificial boundaries may have a profound impact on the overall quality and performance of numerical algorithms. The latter statement is corroborated by the numerous computational experiments and especially concerns the area of CFD, in which external problems present a wide class of practically important formulations. In this paper, we review some work that has been done over the recent years on constructing highly accurate nonlocal ABC's for calculation of compressible external flows. The approach is based on implementation of the generalized potentials and pseudodifferential boundary projection operators analogous to those proposed first by Calderon. The difference potentials method (DPM) by Ryaben'kii is used for the effective computation of the generalized potentials and projections. The resulting ABC's clearly outperform the existing methods from the standpoints of accuracy and robustness, in many cases noticeably speed up the multigrid convergence, and at the same time are quite comparable to other methods from the standpoints of geometric universality and simplicity of implementation.

Ryaben 'Kii, Victor S.; Tsynkov, Semyon V.

1997-01-01

255

Comparing the Biogeochemical Potential of Hyporheic Zones Driven by Different River Morphologies  

NASA Astrophysics Data System (ADS)

Channel morphology controls the hydrodynamics of hyporheic exchange and its residence times. As a result, it also constrains the hyporheic zone's biogeochemical processes that transform carbon, nutrients, metals, and contaminants and the hyporheic zone's net effect at the local, reach and watershed scales. Previous studies of different morphologies (e.g., meanders, bars, and smaller bedforms such as dunes) have mainly focused on the amount of exchange or, if biogeochemistry was involved, have been specific to a particular morphology. In this work, we present a quantitative intercomparison of the amount of exchange, residence time distributions (RTDs), and biogeochemical potential for four channel morphologies: ripples, dunes, bars, and meander bends. To this end, simple two-dimensional conceptualizations and semi-analytical solutions for the hyporheic zone's flow and transport are used. In general, all morphologies are characterized by heavy-tail RTDs, implying long-term memory to solute inputs. We hypothesize that even though meander bends induce larger hyporheic exchange per unit length of channel and longer residence times, substrate limitations result in less biogeochemical processing when compared with the cumulative effect of multiple bedforms. The models presented are a function of geometric and physical properties easily measured or constrained with field or remote sensing data. The simplicity of this approach allows for practical calculations of the hyporheic zone's exchange and biogeochemical potential over a broad range of scenarios and morphologies, making it a useful tool for experimental design, sampling, and watershed scale assessment.

Gomez, J. D.; Harvey, J. W.

2013-12-01

256

Intestinal Diffuse Large B-Cell Lymphoma: An Evaluation of Different Staging Systems  

PubMed Central

The gastrointestinal tract is the most common primary extranodal site for diffuse large B-cell lymphoma (DLBCL). However, there is no consensus on the most appropriate staging system for intestinal DLBCL. We evaluated the utility of the modified Ann Arbor system, the Lugano system, and the Paris staging system (a modification of the Tumor, Node, Metastases [TNM] staging for epithelial tumors) in 66 cases of resected intestinal DLBCL. The cases were treated with surgery, plus either cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) chemotherapy alone (n=26) or with the addition of rituximab immunotherapy (n=40). Median follow-up time was 40.4 months (range, 2.1-171.6 months). Fifty-six patients (84.8%) achieved complete remission. The overall 5-yr survival rate was 86.4% (57/66). Of the stage categories defined for each staging system, only the T stage of the Paris classification showed prognostic significance for overall survival by univariate analysis. However, none of the stage parameters was significantly correlated with patient survival on multivariate analysis. In conclusion, the results suggest that the T stage of the Paris classification system may be a prognostic indicator in intestinal DLBCL. The results also imply that in surgically resected intestinal DLBCL, the addition of rituximab to the CHOP regimen does not confer significant survival advantage.

Hwang, Hee Sang; Yoon, Dok Hyun; Suh, Cheolwon; Park, Chan-Sik

2014-01-01

257

Measurement of molecular attraction between solid bodies of different nature at large distances  

NASA Astrophysics Data System (ADS)

A beam balance has been constructed with negative feed-back allowing the force of molecular attraction between plane and convex solid surfaces of fused quartz, mixed thallium halides and chromium to be measured over distances between 0·1 and 1 ?. Special care was taken to remove the electrical charges on the respective surfaces before the measurements. Measurements were carried out both in the presence of air and in a vacuum of sufficient pressure, from 0·01 to 0·1 mm Hg. The energy of interaction per unit surface are was calculated from the experimental data as a function of the gap width. The results are in good agreement, within the limits of experimental error, with the formula for the limit case of large distances in the general theory of molecular attraction between macro-objects developed by E. M. Lifschitz. This confirms indirectly the London formula for the interaction of the molecular pairs, this formula being derived as another particular limit case from the Lifschitz theory. It also confirms the electromagnetic nature of molecular forces, as indicated by P. N. Lebedev.

Abrikossova, I. I.; Derjaguin, B. V.

1992-05-01

258

Electrical potential difference, sodium absorption and potassium secretion by the human rectum during carbenoxolone therapy.  

PubMed Central

The transmucosal electrical potential difference (pd) and the sodium and potassium net fluxes were measured in the rectum of subjects taking carbenoxolone. There was a rise in transmucosal pd persisting throughout treatment in all subjects which was accompanied by an increase in sodium absorption and potassium secretion. Comparison of the pd changes produced by carbenoxolone with those due to the mineralocorticoid 9-alpha-fluorocortisol showed that carbenoxolone had about 1/1000th the potency on a weight basis and the two drugs appeared to be additive in their effects. Topical instillation of carbenoxolone into the rectum produced an elevation of pd which persisted for three days. Amiloride and bendrofluazide did not interfere with these actions of carbenoxolone but spironolactone abolished them. One patient who developed fluid retention and hypokalaemia had a rectal pd similar to that of the other patients who had no side effects.

Tomkins, A M; Edmonds, C J

1975-01-01

259

Primary task event-related potentials related to different aspects of information processing  

NASA Technical Reports Server (NTRS)

The results of two studies which investigated the relationships between cognitive processing and components of transient event-related potentials (ERPs) are presented in a task in which mental workload was manipulated. The task involved the monitoring of an array of discrete readouts for values that went out of bounds, and was somewhat analogous to tasks performed in cockpits. The ERPs elicited by the changing readouts varied with the number of readouts being monitored, the number of monitored readouts that were close to going out of bounds, and whether or not the change took a monitored readout out of bounds. Moreover, different regions of the waveform differentially reflected these effects. The results confirm the sensitivity of scalp-recorded ERPs to the cognitive processes affected by mental workload and suggest the possibility of extracting useful ERP indices of primary task performance in a wide range of man-machine settings.

Munson, Robert C.; Horst, Richard L.; Mahaffey, David L.

1988-01-01

260

Differences Between Synaptic Plasticity Thresholds Result in New Timing Rules for Maximizing Long-Term Potentiation  

PubMed Central

The fundamental observation that the temporal spacing of learning episodes plays a critical role in the efficiency of memory encoding has had little effect on either research on long-term potentiation (LTP) or efforts to develop cognitive enhancers. Here we review recent findings describing a spaced trials phenomenon for LTP that appears to be related to recent evidence that plasticity thresholds differ between synapses in the adult hippocampus. Results of tests with one memory enhancing drug suggest that the compound potently facilitates LTP via effects on high threshold synapses and thus alters the temporally extended timing rules. Possible implications of these results for our understanding of LTP substrates, neurobiological contributors to the distributed practice effect, and the consequences of memory enhancement are discussed.

Lynch, Gary; Kramar, Eniko A.; Babayan, Alex H.; Rumbaugh, Gavin; Gall, Christine M.

2012-01-01

261

Potential difference and current in simple electric circuits: A study of studentâs concepts  

NSDL National Science Digital Library

A study which was designed to identify students' concepts of simple electric circuits is reported. A diagnostic questionnaire was administered to a sample of 145 high school students and 21 physics teachers. The questionnaire included mainly qualitative questions which were designed to examine students' understanding of the functional relationships between the variables in an electric circuit. The main findings obtained from the analysis of the responses are current is the primary concept used by students, whereas potential difference is regarded as a consequence of current flow, and not as its cause. Consequently students often use V=IR incorrectly. A battery is regarded as a source of constant current. The concepts of emf and internal resistance are not well understood. Students have difficulties in analyzing the effect which a change in one component has on the rest of the circuit. This is probably due to the more general difficulty students have in dealing with a simultaneous change of several variables.

Cohen, R.; Eylon, Bat-Sheva; Ganiel, Uri

2005-10-11

262

The potential of the flora from different regions of Pakistan in phytoremediation: a review.  

PubMed

Soil and water quality is greatly affected by environmental pollution due to the increasing trend of urbanization and industrialization. In many developing countries, including Pakistan, the situation is more alarming as no preventive measures are still taken to tackle the problem. Although in developed countries, many techniques are used to remediate the environment including phytoremediation. It is the most eco-friendly technique in which plants are used to remove pollutants from the environment. Pakistan has also a great diversity of plants which could be used for the remediation of environmental pollutants. To our knowledge, few studies from Pakistan were reported about the use of flora for phytoremediation. According to recent literature, 50 plant species from Pakistan are studied for remediation purposes. In this review, the potential of different plant species for phytoremediation from Pakistan has been discussed along with their comparison to other countries to relate future perspectives. PMID:24091528

Kamran, Muhammad Aqeel; Amna; Mufti, Rabia; Mubariz, Nadia; Syed, Jabir Hussain; Bano, Asghari; Javed, Muhammad Tariq; Munis, Muhammad Farooq Hussain; Tan, Zhiyuan; Chaudhary, Hassan Javed

2014-01-01

263

Chemistry and potential mutagenicity of humic substances in waters from different watersheds in Britain and Ireland  

USGS Publications Warehouse

Humic substances are amorphous organic macromolecules responsible for the hue of natural waters. They are also known to be precursors of mutagens formed on chlorination prior to distribution of drinking water. In this study humic substances from the waters of primary streams, from major rivers, and from reservoirs were isolated and fractionated into humic acids (HA), fulvic acids (FA) and XAD-4 acids using columns of XAD-8 and of XAD-4 resins in tandem, and the fractions from the different sources were chlorinated and assayed for mutagenicity. CPMAS 13C NMR spectroscopy showed marked differences in compositions not only between HA, FA, and XAD-4 acids from the same water samples, but also between the same fractions from water samples from different watersheds. There were found to be strong similarities between the fractions from watersheds which had closely related soil types. Aromaticity was greatest in HAs, and lowest in XAD-4 acids, and carboxyl contents and aliphatic character were greatest in the XAD-4 acids. Carbon content decreased in the order HA > FA > XAD-4 acids, and amino acids and neutral sugars contents decreased in the order HA > XAD-4 > FA. Titration data complemented aspects of the NMR data, demonstrating that carboxyl content decreased in the order XAD-4 acids > FA > HA, and indicated that phenolic character was highest in HAs and lowest in the XAD-4 acids. All samples tested gave rise to bacterial mutagens on chlorination. Although the mutagenicities were of the same order of magnitude for the chlorinated humic samples from the different sources, the samples which showed the greatest number of revertant bacterial colonies were from the Thames and Trent, large rivers with humic materials from diverse environments, and relatively high in amino acid contents.

Watt, B. E.; Malcolm, R. L.; Hayes, M. H. B.; Clark, N. W. E.; Chipman, J. K.

1996-01-01

264

The emission potential of different land use patterns for the occurrence of coliphages in surface water.  

PubMed

Different land use patterns were investigated for their potential as non-point sources of coliphage emissions into surface waters. Water samples were taken regularly at five locations in the upper reaches of the river Swist, Germany. Samples of surface and subsurface run-off were taken within the same catchment area after rainfall events using a newly developed device that made it possible to collect current concentrations of the effluent compounds. The water quality was examined for the occurrence of somatic coliphages and F(+)-specific RNA-bacteriophages as well as for various bacteria over the period of a hydrological year. The potential of various bacteria as indicators for the occurrence of phages was evaluated using statistical correlations. The load of coliphages varied depending on the land use type, but it did not differ as much as the bacterial parameters. River sections in intensively used areas turned out to be more contaminated than in less intensively used regions. The concentrations of phages from surface and subsurface run-off in most samples were quite low for all land use types and did not show conspicuous variations of surface and subsurface run-off within one land use type. Therefore, high concentrations of phages in river water cannot be explained only by non-point effluent from open ground. Following consideration of the statistical results, conventional indicator bacteria seem not to be reliable indicator organisms for coliphages and subsequently for human pathogen viruses. The detected concentrations of coliphages in several water samples of river sections surrounded by intensively used areas underpin an existing health risk in the use of river water for e.g. recreational activities or irrigation. PMID:18804417

Franke, Christiane; Rechenburg, Andrea; Baumanns, Susanne; Willkomm, Marlene; Christoffels, Ekkehard; Exner, Martin; Kistemann, Thomas

2009-05-01

265

Differences in allergenic potential of food extracts following oral exposure in mice reflect differences in digestibility: potential approaches to safety assessment.  

PubMed

An animal model for food allergy is needed to assess genetically modified food crops for potential allergenicity. The ideal model must produce allergic antibody (IgE) to proteins differentially according to known allergenicity before being used to accurately identify potential allergens among novel proteins. The oral route is the most relevant for exposure to food antigens, and a protein's stability to digestion is a current risk assessment tool based on this natural route. However, normal laboratory animals do not mount allergic responses to proteins administered orally due to oral tolerance, an immunologic mechanism which specifically suppresses IgE. To circumvent oral tolerance and evoke differential IgE responses to a panel of allergenic and nonallergenic food extracts, female C3H/HeJ mice were exposed subcutaneously or orally with cholera toxin as an adjuvant. All foods elicited IgE by the subcutaneous route. Oral exposure, however, resulted in IgE to allergens (peanut, Brazil nut, and egg white) but not to nonallergens (spinach and turkey), provided that the dose and exposures were limited. Additionally, in vitro digestibility assays demonstrated the presence of digestion-stable proteins in the allergenic food extracts but not in the nonallergenic foods. Our results suggest that the subcutaneous route is inadequate to distinguish allergens from nonallergens, but oral exposure under the appropriate experimental conditions will result in differential allergic responses in accordance with known allergenicity. Moreover, those foods containing digestion-resistant proteins provoke allergic responses in this model, supporting the current use of pepsin resistance in the decision tree for potential allergenicity assessment. PMID:18033772

Bowman, Christal C; Selgrade, Maryjane K

2008-03-01

266

Addressing impacts of different statistical downscaling methods on large scale hydrologic simulations  

NASA Astrophysics Data System (ADS)

Many hydrologic assessments, such as evaluations of climate change impacts on water resources, require downscaled climate model outputs to force hydrologic simulations at a spatial resolution finer than the climate models' native scale. Statistical downscaling is an attractive alternative to dynamical downscaling methods for continental scale hydrologic applications because of its lower computational cost. The goal of this study is to illustrate and compare how the errors in precipitation and temperature produced by different statistical downscaling methods propagate into hydrologic simulations. Multi-decadal hydrologic simulations were performed with three process-based hydrologic models (CLM, VIC, and PRMS) forced by multiple climate datasets over the contiguous United States. The forcing datasets include climate data derived from gauge observations (M02) as well as climate data downscaled from the NCEP-NCAR reanalysis using 4 statistical downscaling methods for a domain with 12-km grid spacing: two forms of Bias Corrected Spatially Disaggregated methods (BCSD-monthly and BCSD-daily), Bias Corrected Constructed Analogue (BCCA), and Asynchronous Regression (AR). Our results show that both BCCA and BCSD-daily underestimate extreme precipitation events while AR produces these correctly at the scale at which the simulations were run but does not scale them up appropriately to larger basin scales like HUC-4 and HUC-2. These artifacts lead to a poor representation of flooding events when hydrologic models are forced by these methods over a range of spatial scales. We also illustrate that errors in precipitation depths dominate impacts on runoff depth estimations, and that errors in wet day frequency have a larger effect on shortwave radiation estimations than do the errors in temperatures; this error subsequently affects the partitioning of precipitation into evaporation and runoff as we show over mountainous areas of the upper Colorado River. Finally we show the inter-model differences across our simulations are generally lower than than inter-forcing data differences. We conclude with preliminary guidance on sound methodological choices for future climate impact studies using these methods. Comparison of annual precipitation between statistically downscaled data and observation (M02) and illustration of how these differences propagate into hydrologic simulations with two models. Figure shows the simulations over the western United States.

Mizukami, N.; Clark, M. P.; Gutmann, E. D.; Mendoza, P. A.; Brekke, L. D.; Arnold, J.; Raff, D. A.

2013-12-01

267

Are large time differences in meteorite formation real. [cosmochronological dating and nucleosynthetic ratios  

NASA Technical Reports Server (NTRS)

Considerations are given concerning the interpretation of the results of two types of cosmochronological dating in order to examine the validity of the conclusions inferred from these results that the time intervals between the formation of various meteorite samples are very great. It is theorized that the isotopic differences between Angra dos Reis and other basaltic achondrites may be due to real fluctuations between the relative abundances of s-process and r-process nucleosynthesis products at a level delta about 0.001.

Cameron, A. G. W.

1973-01-01

268

Potential of cell retention techniques for large-scale high-density perfusion culture of suspended mammalian cells.  

PubMed

This review focuses on cultivation of mammalian cells in a suspended perfusion mode. The major technological limitation in the scaling-up of these systems is the need for robust retention devices to enable perfusion of medium as needed. For this, cell retention techniques available to date are presented, namely, cross-flow filters, hollow fibers, controlled-shear filters, vortex-flow filters, spin-filters, gravity settlers, centrifuges, acoustic settlers, and hydrocyclones. These retention techniques are compared and evaluated for their respective advantages and potential for large-scale utilization in the context of industrial manufacturing processes. This analysis shows certain techniques have a limited range of perfusion rate where they can be implemented (most microfiltration techniques). On the other hand, techniques were identified that have shown high perfusion capacity (centrifuges and spin-filters), or have a good potential for scale-up (acoustic settlers and inclined settlers). The literature clearly shows that reasonable solutions exist to develop large-scale perfusion processes. PMID:12701141

Voisard, D; Meuwly, F; Ruffieux, P-A; Baer, G; Kadouri, A

2003-06-30

269

Difference of Diagnostic Rates and Analytical Methods in the Test Positions of Vestibular Evoked Myogenic Potentials  

PubMed Central

Objective To compare the differences of diagnostic rates, of the two widely used test positions, in measuring vestibular evoked myogenic potentials (VEMP) and selecting the most appropriate analytical method for diagnostic criteria for the patients with vertigo. Methods Thirty-two patients with vertigo were tested in two comparative testing positions: turning the head to the opposite side of the evaluating side and bowing while in seated position, and bowing while in supine positions. Abnormalities were determined by prolonged latency of p13 or n23, shortening of the interpeak latency, and absence of VEMP formation. Results Using the three criteria above for determining abnormalities, both the seated and supine positions showed no significant differences in diagnostic rates, however, the concordance correlation of the two positions was low. When using only the prolonged latency of p13 or n23 in the two positions, diagnostic rates were not significantly different and their concordance correlation was high. On the other hand, using only the shortened interpeak latency in both positions showed no significant difference of diagnostic rates, and the degree of agreement between two positions was low. Conclusion Bowing while in seated position with the head turned in the opposite direction to the area being evaluated is found to be the best VEMP test position due to the consistent level of sternocleidomastoid muscle tension and the high level of compliance. Also, among other diagnostic analysis methods, using prolonged latency of p13 or n23 as the criterion is found to be the most appropriate method of analysis for the VEMP test.

Park, Jeong Mee; Yong, Sang Yeol; Kim, Jong Heon; Kim, Hee; Park, Sang-Yoo

2014-01-01

270

Simulated environmental criticalities affect transglutaminase of Malus and Corylus pollens having different allergenic potential.  

PubMed

Increases in temperature and air pollution influence pollen allergenicity, which is responsible for the dramatic raise in respiratory allergies. To clarify possible underlying mechanisms, an anemophilous pollen (hazel, Corylus avellana), known to be allergenic, and an entomophilous one (apple, Malus domestica), the allergenicity of which was not known, were analysed. The presence also in apple pollen of known fruit allergens and their immunorecognition by serum of an allergic patient were preliminary ascertained, resulting also apple pollen potentially allergenic. Pollens were subjected to simulated stressful conditions, provided by changes in temperature, humidity, and copper and acid rain pollution. In the two pollens exposed to environmental criticalities, viability and germination were negatively affected and different transglutaminase (TGase) gel bands were differently immunodetected with the polyclonal antibody AtPng1p. The enzyme activity increased under stressful treatments and, along with its products, was found to be released outside the pollen with externalisation of TGase being predominant in C. avellana, whose grain presents a different cell wall composition with respect to that of M. domestica. A recombinant plant TGase (AtPng1p) stimulated the secreted phospholipase A(2) (sPLA(2)) activity, that in vivo is present in human mucosa and is involved in inflammation. Similarly, stressed pollen, hazel pollen being the most efficient, stimulated to very different extent sPLA(2) activity and putrescine conjugation to sPLA(2). We propose that externalised pollen TGase could be one of the mediators of pollen allergenicity, especially under environmental stress induced by climate changes. PMID:21847612

Iorio, Rosa Anna; Di Sandro, Alessia; Paris, Roberta; Pagliarani, Giulia; Tartarini, Stefano; Ricci, Giampaolo; Serafini-Fracassini, Donatella; Verderio, Elisabetta; Del Duca, Stefano

2012-02-01

271

Disruption of Prefrontal Cortex Large Scale Neuronal Activity by Different Classes of Psychotomimetic Drugs  

PubMed Central

In the absence of overt cellular pathology but profound perceptual disorganization and cognitive deficits, schizophrenia is increasingly considered a disorder of neural coordination. Thus, different causal factors can similarly interrupt the dynamic function of neuronal ensembles and networks, in particular in the prefrontal cortex (PFC), leading to behavioral disorganization. The importance of establishing preclinical biomarkers for this aberrant function has prompted investigations into the nature of psychotomimetic drug effects on PFC neuronal activity. The drugs used in this context include serotonergic hallucinogens, amphetamine, and NMDA receptor antagonists. A prominent line of thinking is that these drugs create psychotomimetic states by similarly disinhibiting the activity of PFC pyramidal neurons. In the present study we did not find evidence in support of this mechanism in PFC subregions of freely moving rats. Whereas the NMDA receptor antagonist MK801 increased PFC population activity, the serotonergic hallucinogen DOI dose-dependently decreased population activity. Amphetamine did not strongly affect this measure. Despite different effects on the direction of change in activity, all three drugs caused similar net disruptions of population activity and modulated gamma oscillations. We also observed reduced correlations between spikerate and LFP power selectively in the gamma band suggesting that these drugs disconnect spike-discharge from PFC gamma oscillators. Gamma band oscillations support cognitive functions affected in schizophrenia. These findings provide insight into mechanisms that may lead to cortical processing deficits in schizophrenia and provide a novel electrophysiological approach for phenotypic characterization of animal models of this disease.

Wood, Jesse; Kim, Yunbok; Moghaddam, Bita

2012-01-01

272

Large work function difference driven electron transfer from electrides to single-walled carbon nanotubes.  

PubMed

A difference in work function plays a key role in charge transfer between two materials. Inorganic electrides provide a unique opportunity for electron transfer since interstitial anionic electrons result in a very low work function of 2.4-2.6 eV. Here we investigated charge transfer between two different types of electrides, [Ca2N](+)·e(-) and [Ca24Al28O64](4+)·4e(-), and single-walled carbon nanotubes (SWNTs) with a work function of 4.73-5.05 eV. [Ca2N](+)·e(-) with open 2-dimensional electron layers was more effective in donating electrons to SWNTs than closed cage structured [Ca24Al28O64](4+)·4e(-) due to the higher electron concentration (1.3 × 10(22) cm(-3)) and mobility (?200 cm(2) V(-1) s(-1) at RT). A non-covalent conjugation enhanced near-infrared fluorescence of SWNTs as high as 52%. The field emission current density of electride-SWNT-silver paste dramatically increased by a factor of 46?000 (14.8 mA cm(-2)) at 2 V ?m(-1) (3.5 wt% [Ca2N](+)·e(-)) with a turn-on voltage of 0.85 V ?m(-1). PMID:24956225

Menamparambath, Mini Mol; Park, Jong-Ho; Yoo, Ho-Sung; Patole, Shashikant P; Yoo, Ji-Beom; Kim, Sung Wng; Baik, Seunghyun

2014-07-10

273

A conserved mechanism controls translation of Rubisco large subunit in different photosynthetic organisms.  

PubMed

We previously proposed a mechanism for control of Rubisco expression and assembly during oxidative stress in Chlamydomonas reinhardtii. The N terminus of the large subunit (LSU) comprises an RNA recognition motif (RRM) that is normally buried in the protein, but becomes exposed under oxidizing conditions when the glutathione pool shifts toward its oxidized form. Thus, de novo translation and assembly of Rubisco LSU stop with similar kinetics and the unpaired small subunit (SSU) is rapidly degraded. Here we show that the structure of the N-terminal domain is highly conserved throughout evolution, despite its relatively low sequence similarity. Furthermore, Rubisco from a broad evolutionary range of photosynthetic organisms binds RNA under oxidizing conditions, with dissociation constant values in the nanomolar range. In line with these observations, oxidative stress indeed causes a translational arrest in land plants as well as in Rhodospirillum rubrum, a purple bacterium that lacks the SSU. We highlight an evolutionary conserved element located within alpha-helix B, which is located in the center of the RRM and is also involved in the intramolecular interactions between two LSU chains. Thus, assembly masks the N terminus of the LSU hiding the RRM. When assembly is interrupted due to structural changes that occur under oxidizing conditions or in the absence of a dedicated chaperone, the N-terminal domain can become exposed, leading to the translational arrest of Rubisco LSU. Taken together, these results support a model by which LSU translation is governed by its dimerization. In the case that regulation of type I and type II Rubisco is conserved, the SSU does not appear to be directly involved in LSU translation. PMID:16731581

Cohen, Idan; Sapir, Yair; Shapira, Michal

2006-07-01

274

bZIPs and WRKYs: two large transcription factor families executing two different functional strategies  

PubMed Central

bZIPs and WRKYs are two important plant transcription factor (TF) families regulating diverse developmental and stress-related processes. Since a partial overlap in these biological processes is obvious, it can be speculated that they fulfill non-redundant functions in a complex regulatory network. Here, we focus on the regulatory mechanisms that are so far described for bZIPs and WRKYs. bZIP factors need to heterodimerize for DNA-binding and regulation of transcription, and based on a bioinformatics approach, bZIPs can build up more than the double of protein interactions than WRKYs. In contrast, an enrichment of the WRKY DNA-binding motifs can be found in WRKY promoters, a phenomenon which is not observed for the bZIP family. Thus, the two TF families follow two different functional strategies in which WRKYs regulate each other’s transcription in a transcriptional network whereas bZIP action relies on intensive heterodimerization.

Llorca, Carles M.; Potschin, Maren; Zentgraf, Ulrike

2014-01-01

275

Assessing the impact of different satellite retrieval methods on forecast available potential energy  

NASA Technical Reports Server (NTRS)

The effects of the inclusion of satellite temperature retrieval data, and of different satellite retrieval methods, on forecasts made with the NASA Goddard Laboratory for Atmospheres (GLA) fourth-order model were investigated using, as the parameter, the available potential energy (APE) in its isentropic form. Calculation of the APE were used to study the differences in the forecast sets both globally and in the Northern Hemisphere during 72-h forecast period. The analysis data sets used for the forecasts included one containing the NESDIS TIROS-N retrievals, the GLA retrievals using the physical inversion method, and a third, which did not contain satellite data, used as a control; two data sets, with and without satellite data, were used for verification. For all three data sets, the Northern Hemisphere values for the total APE showed an increase throughout the forecast period, mostly due to an increase in the zonal component, in contrast to the verification sets, which showed a steady level of total APE.

Whittaker, Linda M.; Horn, Lyle H.

1990-01-01

276

Relationship between brain and liver oxidative state and maximum lifespan potential of different fish species.  

PubMed

The aim of the present study is to determine whether a relationship exists between the maximum lifespan potential (MLSP) of different fish species (Squalius pyrenaicus, Cyprinus carpio, Carassius auratus, Luciobarbus sclateri and Oncorhynchus mykiss) and the oxidative state of brain and liver. For this purpose, the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX), glutathione reductase (GR), glutathione S-transferase (GST) and DT-diaphorase (NAD(P)H:quinone oxidoreductase1) were measured together with the lipid peroxidation degree (malondialdehyde, MDA) in liver and brain tissues of the collected species. Only the brain tissue manifested a higher activity of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and glutathione S-transferase in addition to a negative correlation between the values of MDA and MLSP among the different fish species. Hypotheses are proposed from the analysis of the obtained results that open new areas of research and converge on the importance of the theory of free radicals in the processes that condition the maximum life expectancy of an animal species. PMID:23618756

Sanz, A; Trenzado, C E; Botello Castro, H; López-Rodríguez, M J; Tierno de Figueroa, J M

2013-07-01

277

Normative data for vestibular evoked myogenic potential in different age groups among a heterogeneous Indian population.  

PubMed

To establish normative data of vestibular evoked myogenic potential in different age groups among a heterogeneous Indian population. Prospective study design using a sample of convenience. Eighty five normal controls ranging between the ages 7 and 71 years were asked to provide a written signed consent for the study. Demographic characteristics of the patients were summarized using descriptive statistical methods using SPSS-17 analysing software. The outcome variable (VEMP recording) was expressed in percentiles as function of age. In all patients the stimulus which gave the best response was 95 dB (97.7 %) and 100 dB (95 %). The mean of wave latencies (p1 & n1) for 95-VEMP were, 11.2 ± 3.2 and 17.3 ± 4.7 ms on the right and 11.0 ± 2.8 and 17.0 ± 4.2 ms on the left respectively. The amplitude was 45.1 ± 54 mV on right and 46.9 ± 61.6 mV on the left. The mean of latency difference was 0.87 ms. The VEMP is a relatively simple test. The VEMP response rate was maximum in the younger age group; the optimum intensity was 95 dB. The asymmetry ratio interpretation should be done according to the age specific values. PMID:24822153

Khan, Feroze K; Balraj, Achamma; Lepcha, Anjali

2014-06-01

278

Dynamics of large landslide movement over coal mine Angren, in period of different strong distant earthquakes  

NASA Astrophysics Data System (ADS)

In 1985, on the working coal mine Angren board began to develop landslide "Central", and another landslide "Old substation" formed in 1993. In 2001 the process of connecting these two adjacent sites has been started, and in 2011 two landslides were merged. As a result, the upper band formed graben like longitudinal down warping with width 150 m, length 1400 m and an amplitude of 0.5-2 m, volume of the landslide was 120-130 m3. Motion of the landslide mass with average thickness of 100 m occurs in a shallow surface 40 in the contact zone of limestone with fine-grained sands and greenish clays of Paleogene. Merging of landslides occurred in result of earthquake impact from Hindu Kush in March 21, 2011, M = 5.8, at depth 196 km. Intensity of motions in Angren 2-3 units and effective duration of 105 seconds. Geodetic GPS measurements carried out there since 2005, regular cycle was held March, 21 in the morning before the earthquake, after 10-12 hours the earthquake was carried out repeated measurement. There was a sharp increase in groundwater discharge, in the upper ledges of mine was formed lake 20-25 m long, 15 m wide and 1 m deep. At the bottom of the mine employees watched the water flow, which probably is connected with the vibration and deformation of the underground hydrogeological system. The rate of displacement of landslide in the day of the earthquake is not sharply increased. It began to be accelerated in the course of 57 days (21.03-17.05) in the Central zone from 168 to 749 mm / day and 79 days (21.03-8.06) in the upper zone from 68 to 385.4 mm/day. Then, the displacement velocity began to decline during the past two months to 310.8 mm/day (middle) and 255 mm / day in the upper zone. In 19.07.2011, there was a local earthquake in Kyrgyzstan, M = 6.2, H = 10-12 km, distance 135 km from Angren with intensity of 5 units, duration of horizontal vibrations 60-70 seconds. By carried out repeated GPS measurements after 12 hours, the acceleration of the displacement was noted only in one benchmark (6), located in the upper zone, where the vertical displacement increased to 431 mm/day and subsided to 2-2.5 m. The horizontal dis-placement for 5 days before the earthquake was equal to 255 mm/day, after the earthquake, 223 mm/day, i.e. this earthquake did not cause the rate change. Thus, two different earth-quakes, occurred at different times caused different effects, but activation of the landslide determines by the state of critical stability of mine board.

Nyazov, R.; Nurtaev, B.

2011-12-01

279

A Large Gene Cluster Encoding Several Magnetosome Proteins Is Conserved in Different Species of Magnetotactic Bacteria  

PubMed Central

In magnetotactic bacteria, a number of specific proteins are associated with the magnetosome membrane (MM) and may have a crucial role in magnetite biomineralization. We have cloned and sequenced the genes of several of these polypeptides in the magnetotactic bacterium Magnetospirillum gryphiswaldense that could be assigned to two different genomic regions. Except for mamA, none of these genes have been previously reported to be related to magnetosome formation. Homologous genes were found in the genome sequences of M. magnetotacticum and magnetic coccus strain MC-1. The MM proteins identified display homology to tetratricopeptide repeat proteins (MamA), cation diffusion facilitators (MamB), and HtrA-like serine proteases (MamE) or bear no similarity to known proteins (MamC and MamD). A major gene cluster containing several magnetosome genes (including mamA and mamB) was found to be conserved in all three of the strains investigated. The mamAB cluster also contains additional genes that have no known homologs in any nonmagnetic organism, suggesting a specific role in magnetosome formation.

Grunberg, Karen; Wawer, Cathrin; Tebo, Bradley M.; Schuler, Dirk

2001-01-01

280

Modeling the large-scale water balance impact of different irrigation systems  

NASA Astrophysics Data System (ADS)

In this study, two parameterizations for different irrigation techniques have been implemented in a regional climate model. These implementations allow for a comparative study of water use and land-atmosphere interactions associated with traditional flood irrigation—a widespread but highly water-inefficient practice—and water-conserving drip irrigation. Both parameterizations yield realistic results for coupled climate simulations, and do so without the need to reproduce an entire crop model within the climate model. Simulations with drip irrigation exhibit ˜30% less irrigation season evapotranspiration and ˜60% less water demand overall relative to simulations with flood irrigation. Examination of the water balance for various irrigation zones in Syria and Turkey demonstrates that planned Syrian irrigation expansion in the Euphrates watershed is only feasible if accompanied by modernization. Even then, planned expansion in the Khabur watershed, a major tributary of the Euphrates, would only reach sustainability if there is significant irrigation water runoff into Syria from Turkey. Thus Syria has a window of opportunity within which it can reap the benefits of investing in modernization and expansion of irrigation. That window begins now, with the Syrian governments recent commitment to modernize its irrigation infrastructure, and in the absence of an international water-sharing agreement, ends when increased water demand and/or decreased precipitation causes the Turkish government to invest in modernizing its own irrigation systems. Such a precipitation decrease is predicted to occur in the Middle East by mid-century if greenhouse gas emissions are not curbed substantially.

Evans, J. P.; Zaitchik, B. F.

2008-08-01

281

Hemispheric Lateralization of Event-Related Brain Potentials in Different Processing Phases during Unimanual Finger Movements  

PubMed Central

Previous functional MRI and brain electrophysiology studies have studied the left-right differences during the tapping tasks and found that the activation of left hemisphere was more significant than that of right hemisphere. In this study, we wanted to delineate this lateralization phenomenon not only in the execution phase but also in other processing phases, such as early visual, pre-executive and post-executive phases. We have designed a finger-tapping task to delineate the left-right differences of event related potentials (ERPs) to right finger movement in sixteen right handed college students. The mean amplitudes of ERPs were analyzed to examine the left-right dominance of cortical activity in the phase of early visual process (75-120ms), pre-execution (175-260ms), execution (310-420ms) and post-execution (420-620ms). In the execution phase, ERPs at the left electrodes were significantly more pronounced than those at the right electrodes (F3 > F4, C3 > C4, P3 > P4, O1 > O2) under the situation without comparing the central electrodes (Fz, Cz, Pz, and Oz). No difference was found between left and right electrodes in other three phases except the C3 electrode still showed more dominant than C4 in the pre- and post-execution phase. In conclusion, the phenomenon of brain lateralization occur major in the execution phase. The central area also showed the lateralization in the pre- and post-execution to demonstrate its unique lateralized contributions to unilateral simple finger movements.

Meng, Ling-Fu; Lu, Chiu-Ping; Li, Yi-Wen

2008-01-01

282

Screening candidate metastasis-associated genes in three-dimensional HCC spheroids with different metastasis potential  

PubMed Central

Purpose: Previously, we have established a tissue-like HCC spheroid which better mirrors the biological features of tumorigenesis and metastasis. This study was to find out metastasis-associated genes between two 3D HCC spheroids with different metastasis potential using comparative PCR arrays. Materials and Methods: Two HCC spheroids derived from high-metastatic MHCC97H cells and low-metastatic Hep3B cells were formed respectively in a rotating wall vessel bioreactor after 3D culture for 15 days. The candidate metastasis-associated genes related to cell adhesion, matrix secretion and invasion in HCC spheroids were screened by RT² profiler PCR arrays. The expression patterns of several differentially-expressed genes were further confirmed by real-time RT-PCR. Results: Total of 123 differential expression genes (fold-change >2) were found between two HCC spheroids, including 70 up-regulated genes (VCAM-1, IL-1?, CD44, tenascin C, SPP1, fibronectin, MMP-2, MMP-7, etc) and 53 down-regulated genes (E-cadherin, CTNND2, etc) in the high-metastatic spheroid. Function classification showed that the number of up-regulated genes related to adhesion molecules mediating cell-matrix interactions and matrix secretion was significantly higher in high-metastatic spheroid than that in low-metastatic spheroid. In contrast, the expressions of adhesion molecules maintaining homotypic tumor cell adhesion were decreased in metastatic spheroid as compared with that in low-metastatic spheroid. In addition, the expression pattern of seven selected genes associated with tumor metastasis measured by real-time RT-PCR were consistent with results of PCR arrays. Conclusions: Obvious differences between two HCC spheroids in gene expression patterns of adhesion molecules, matrix secretion, invasion and other molecules may determine the different metastatic characteristics and malignant phenotype of HCC spheroid.

Chen, Rongxin; Dong, Yinying; Xie, Xiaoying; Chen, Jie; Gao, Dongmei; Liu, Yinkun; Ren, Zhenggang; Cui, Jiefeng

2014-01-01

283

Anticancer effect of SN-38 on colon cancer cell lines with different metastatic potential.  

PubMed

SN-38 is an active metabolite of the topoisomerase I inhibitor irinotecan. The mechanism behind its antitumor effect in colorectal cancer is not fully understood. In this study, we examined the response of colon cancer cell lines with different metastatic potential to SN-38. The parental human colon cancer cell line KM12C and its two highly metastatic derivatives KM12SM and KM12L4a were cultivated in 5% CO2 at 37 degrees C for 24 h and then exposed to SN-38 (2.5 microg/ml) at 37 degrees C for 4, 24 and 48 h, respectively. The cell cycle was measured by flow cytometry, apoptotic activity was determined by flow cytometry and immunocytochemistry and the expression of topoisomerase I, Bax and survivin proteins were examined by Western blot. The exposure of the cells to SN-38 induced S-phase and G2 arrest (P<0.0001) and the KM12L4a cells had the highest response in a time-dependent manner (P<0.0001). The rates of apoptosis in the KM12SM (P=0.001) and KM12L4a cell lines (P=0.01) were increased time-dependently, though there was no such change in the KM12C cells. The expression of topoisomerase I protein was decreased in each cell line tested and the expression of Bax protein was increased, especially in KM12L4a. In conclusion, the effect of SN-38 on the colon cancer cell lines was mediated via conducting S-phase and G2 arrest and apoptosis. This effect was found in the cell lines with higher metastatic potentials, indicating that SN-38 can be used to treat advanced colon cancers. PMID:18497955

Wallin, Asa; Svanvik, Joar; Holmlund, Birgitta; Ferreud, Lillianne; Sun, Xiao-Feng

2008-06-01

284

Interactions between oestrogen and the renin angiotensin system - potential mechanisms for gender differences in Alzheimer's disease  

PubMed Central

Interactions between oestrogen and the renin angiotensin system (RAS) are reviewed and explored from the perspective where these interactions may modulate risk of developing Alzheimer’s disease (AD). AD is more prevalent in women than men, partly attributed to women’s increased life expectancy; however underlying vascular differences may also contribute to AD risk. The RAS is a key regulator of blood pressure (BP). Pharmacological inhibition of angiotensin converting enzyme (ACE) and blockade of angiotensin II type 1 receptors (AT1R) are widely used to treat hypertension. Variation in components of the RAS such as ACE, neprilysin (NEP) and AT1R have been reported in AD, some of which may also directly alter AD neuropathology with changes in amyloid beta (A?) levels, cognitive decline and neuroinflammation. Recently, RAS inhibiting drugs have been shown to attenuate the incidence, progression and pathology of AD. Oestrogen is also thought to prevent hypertension by reducing the vasoconstrictive actions of the RAS. Reduced oestrogen levels in women during the menopausal transition may therefore increase their risk of hypertension and/or RAS-mediated changes to cerebrovascular or AD pathology. Specifically, oestrogen prevents the production and action of angiotensin II (Ang II), thought to exert harmful effects of the RAS in both hypertension and AD, while also potentially facilitating RAS-mediated A? degradation. These oestrogen-RAS interactions may partly explain current conflicting findings regarding oestrogen depletion and hormone therapy with respect to AD risk. Clinical trials targeting either the RAS or oestrogen systems for AD prevention and treatment should perhaps give closer attention to key biochemical components of these pathways as potential confounders to primary and secondary outcome measures.

O'Hagan, Thomas Simon; Wharton, Whitney; Kehoe, Patrick Gavin

2012-01-01

285

Satellite DNA hypomethylation vs. overall genomic hypomethylation in ovarian epithelial tumors of different malignant potential.  

PubMed

Rearrangements in heterochromatin in the vicinity of the centromeres of chromosomes 1 and 16 are frequent in many types of cancer, including ovarian epithelial carcinomas. Satellite 2 DNA is the main sequence in the unusually long heterochromatin region adjacent to the centromere of each of these chromosomes. Rearrangements in these regions and hypomethylation of satellite 2 DNA are a characteristic feature of patients with a rare recessive genetic disease, ICF (immunodeficiency, centromeric region instability, and facial anomalies). In all normal tissues of postnatal somatic origin, satellite 2 DNA is highly methylated. We examined satellite 2 DNA methylation in ovarian tumors of different malignant potential, namely, ovarian cystadenomas, low malignant potential (LMP) tumors, and epithelial carcinomas. Most of the carcinomas and LMP tumors exhibited hypomethylation in satellite 2 DNA of both chromosomes 1 and 16. A comparison of methylation of these sequences in the three types of ovarian neoplasms demonstrated that there was a statistically significant correlation between the extent of this satellite DNA hypomethylation and the degree of malignancy (P<0.01). Also, there was a statistically significant association (P<0.005) between genome-wide hypomethylation and undermethylation of satellite 2 DNA among these 17 tumors. In addition, we found abnormal hypomethylation of satellite alpha DNA in the centromere of chromosome 1 in many of these tumors. Our findings are consistent with the hypothesis that one of the ways that genome-wide hypomethylation facilitates tumor development is that it often includes satellite hypomethylation which might predispose cells to structural and numerical chromosomal aberrations. Several of the proteins that bind to pericentromeric heterochromatin are known to be sensitive to the methylation status of their target sequences and so could be among the sensors for detecting abnormal demethylation and mediating effects on chromosome structure and stability. PMID:10029684

Qu, G; Dubeau, L; Narayan, A; Yu, M C; Ehrlich, M

1999-01-25

286

Sediment pollution in the Elbe estuary and its potential toxicity at different trophic levels.  

PubMed

Sediment contamination is one of the most pressing environmental problems in estuaries of industrialized countries and is of special interest to water managers involved in waterway maintenance dredging. In the present study, eight heavy metals (As, Pb, Cd, Cr, Cu, Ni, Hg, and Zn) and 41 organic compounds (pentachlorbenzol (PeCB), hexachlorbenzol (HCB), 7 polychlorinated biphenyls (PCBs), the hexachlorocyclohexanes ?-HCH, ?-HCH, ?-HCH, 6 dichlorodiphenyltrichloroethane isomers, organochlorine styrene (OCS), octachloronaphthalene (OCN), 15 polycyclic aromatic hydrocarbons (PAHs), and 6 organotin (OT) compounds) were analyzed in surface sediments at 36 sites in the Elbe estuary in 2006. Correlation analysis showed a general decrease in sediment contaminant concentrations from the stations near the port of Hamburg towards the open sea. This decrease was significant (Spearman's rank correlation, p<0.05) with most pollutants. In addition, cluster analysis identified five groups of sites with different sediment contaminant patterns within the Elbe estuary. Worst case toxic risks stemming from sediment-bound organic pollutants were predicted using the Toxic Unit approach, based on estimated pore-water concentrations under equilibrium conditions and acute LC50 values for three standard test organisms of the trophic levels of fish, invertebrates, and algae. The estimated sediment toxicity was significantly higher in the inner part (river-km 630 to 660) compared with the estuarine mouth. Moreover, potential toxicity of organic pollutants estimated for invertebrates and for fish exceeded acute-based effect thresholds at 30 and 24 stations, respectively. Chronic effects for invertebrates are expected at all sites investigated. We conclude that sediment pollution and related potential toxicity in the Elbe estuary may have more influence on the benthos fauna than expected to date. PMID:23428749

Wetzel, Markus A; Wahrendorf, Dierk-Steffen; von der Ohe, Peter C

2013-04-01

287

Temporal evolution of plasma potential in a large-area pulsed dual-frequency inductively coupled discharge  

NASA Astrophysics Data System (ADS)

Using an emissive probe technique in ‘saturated floating-potential’ mode, an investigation of temporal evolution of plasma potential (Vp) in a large-area pulsed dual-frequency (2 MHz/13.56 MHz) inductively coupled plasma (p-DF-CCP) is carried out. The discharge is sustained by an external type ICP antenna at a pressure of 10 mTorr in argon gas environment. The 2 MHz rf is pulsed at a frequency of 1 kHz and a duty ratio of 50%. The emissive probe is located at the centre of the substrate and 20 mm above (r = 00 mm and z = -20 mm) it. The low-frequency power (P2 MHz) is varied from 100 to 800 W, whereas the high-frequency power (P13.56 MHz) from 100 to 700 W. Vp remains positive during the whole pulse period. The prominent features in the Vp profile remain similar under all operating conditions; however, the magnitude of Vp depends on the applied rf powers. For further investigation, three distinct regions in a typical Vp profile are clearly identified as ‘overshoot—immediately after pulse begins’, the ‘on-time’ and the ‘off-time’. Vp increases with increasing P13.56 MHz and has reverse trend with P2 MHz. The electron temperature (Te) is calculated using the relation between floating potential (Vf) and plasma potential (Vp) for the argon plasma and it is found that Te increases with increasing P13.56 MHz and decreases with P2 MHz. It is found that Vp could be modulated using a suitable power combination on two frequencies (P13.56 MHz/P2 MHz). This paper is an attempt to investigate the time-resolved Vp and Te with rf powers in a pulsed dual-frequency ICP.

Mishra, Anurag; Seo, Jin Seok; Kim, Kyong Nam; Yeom, Geun Young

2013-06-01

288

Potentials and constraints of different types of soil moisture observations for flood simulations in headwater catchments  

NASA Astrophysics Data System (ADS)

Flood generation in mountainous headwater catchments is governed by rainfall intensities, by the spatial distribution of rainfall and by the state of the catchment prior to the rainfall, e.g. by the spatial pattern of the soil moisture, groundwater conditions, and possibly snow. The work presented here explores the limits and potentials of measuring soil moisture with different methods and in different scales and their potential use for flood simulation. These measurements were obtained in 2007 and 2008 within a comprehensive multi-scale experiment in the Weisseritz headwater catchment in the Ore-Mountains, Germany. The following technologies have been applied jointly thermogravimetric method, Frequency Domain Reflectometry (FDR) sensors, Spatial-Time Domain Reflectometry (STDR) cluster, Ground Penetrating Radar (GPR), airborne polarimetric synthetic aperture radar (polarimetric-SAR) and Advanced Synthetic Aperture Radar (ASAR) based on the satellite Envisat. We present exemplary soil measurement results, with spatial scales ranging from point scale, via hillslope and field scale to the catchment scale. Only the Spatial-TDR cluster was able to record continuous data. The other methods are limited to the date of over flights (airplane and satellite) or measurement campaigns on the ground. At a first glance, using soil moisture data to initiate better flood modelling (including flood forecasts) seems to be a rather straight forward approach. However, this approach bears several problems regarding the operational use of such data and the model parameterisation: 1) A main constraint is that the observation of spatially distributed soil moisture and the subsequent data processing are still far from an operational stage because continuous or quasi-continuous air-borne observation and processing of soil moisture is not available; 2) remote soil moisture sensors observe only a quite shallow soil depths, which are of restricted relevance for flood generation and water budgets, 3) satellite data are not yet readily available continuously and in a way that they can be used directly for flood forecasting, and 4) hydrological models which can directly process such information are not readily available.

Bronstert, A.; Creutzfeldt, B.; Graeff, T.; Hajnsek, I.; Heistermann, M.; Itzerott, S.; Jagdhuber, T.; Kneis, D.; Lück, E.; Reusser, D.; Zehe, E.

2012-04-01

289

Escherichia coli O157 prevalence in different cattle farm types and identification of potential risk factors.  

PubMed

Although the prevalence of Escherichia coli O157 on cattle farms has been examined extensively, the relationship between this pathogen and farm type has been established only rarely. A large-scale study was designed to determine the prevalence of E. coli O157 in the Flemish region of Belgium on farms of dairy cattle, beef cattle, mixed dairy and beef cattle, and veal calves. The effect of various factors on the occurrence at the pen level also was evaluated. In 2007, 180 farms were randomly selected based on region, farm size, and number of animals purchased and were examined using the overshoe sampling method. When possible, overshoes used in areas containing animals in three different age categories (< 8 months, 8 to 30 months, and > 30 months) were sampled on each farm. In total, 820 different pens were sampled and analyzed for the presence of E. coli O157 by enrichment, immunomagnetic separation, and plating on selective agar. Presumptive E. coli O157 colonies were identified using a multiplex PCR assay for the presence of the rfb(O157) and fliC(H7) genes. The statistical analysis was carried out with Stata SE/10.0 using a generalized linear regression model with a logit link function and a binomial error distribution. The overall farm prevalence of E. coli O157 was 37.8% (68 of 180 farms). The highest prevalence was found on dairy cattle farms (61.2%, 30 of 49 farms). The prevalences on beef, mixed dairy and beef, and veal calf farms were 22.7% (17 of 75 farms), 44.4% (20 of 45 farms), and 9.1% (1 of 11 farms), respectively. A significant positive correlation between age category and E. coli O157 prevalence was found only on mixed dairy and beef farms and dairy farms. No influence of farm size or introduction of new animals was demonstrated. PMID:19777885

Cobbaut, K; Berkvens, D; Houf, K; De Deken, R; De Zutter, L

2009-09-01

290

Liquid Hole-Multipliers: A potential concept for large single-phase noble-liquid TPCs of rare events  

NASA Astrophysics Data System (ADS)

A novel concept is proposed for large-volume single-phase noble-liquid TPC detectors for rare events. Both radiation-induced scintillation-light and ionization-charge are detected by Liquid Hole-Multipliers (LHM), immersed in the noble liquid. The latter may consist of cascaded Gas Electron Multipliers (GEM), Thick Gas Electron Multiplier (THGEM) electrodes or others, coated with CsI UV-photocathodes. Electrons, photo-induced on CsI by primary scintillation in the noble liquid, and event-correlated drifting ionization electrons are amplified in the cascaded elements primarily through electroluminescence, and possibly through additional moderate avalanche, occurring within the holes. The resulting charge-signals or light-pulses are recorded on anode pads or with photosensors - e.g. gaseous photomultipliers (GPM), respectively. Potential affordable solutions are proposed for multi-ton dark-matter detectors; open questions are formulated for validating this dream.

Breskin, Amos

2013-10-01

291

A priori tests of a new dynamic subgrid-scale model for finite-difference large-eddy simulations  

Microsoft Academic Search

This work focuses on subgrid-scale (SGS) modeling for finite-difference large-eddy simulations, employing filters in physical space. When a filter in physical space is used, an overlap is allowed between the unresolved and the resolved scales. For such a filter, all the three terms in the classical decomposition of the SGS stress tensor are present: the Leonard and cross-terms, due to

M. V. Salvetti; S. Banerjee

1995-01-01

292

Thermoelectric Behavior of Sb and Al-Doped n Type Mg 2 Si Device Under Large Temperature Differences  

Microsoft Academic Search

The thermoelectric (TE) characteristics of Sb- and Al-doped n-type Mg2Si elemental devices fabricated using material produced from molten commercial doped polycrystalline Mg2Si were examined. The TE devices were prepared using a plasma-activated sintering (PAS) technique. To complete the devices,\\u000a Ni electrodes were fabricated on each end of them during the sintering process. To realize durable devices for large temperature\\u000a differences,

Tatsuya Sakamoto; Tsutomu Iida; Shota Kurosaki; Kenji Yano; Hirohisa Taguchi; Keishi Nishio; Yoshifumi Takanashi

2011-01-01

293

Benchmark solutions for the natural convective heat transfer problem in a square cavity with large horizontal temperature differences  

Microsoft Academic Search

In this study, Benchmark solutions are derived for the problem of two-dimensional laminar flow of air in a square cavity which is heated on the left, cooled on the right and insulated on the top and bottom boundaries. The temperature differences between the hot and cold walls are large. Neither Boussinesq nor low-Mach number approximations of the Navier-Stokes equations are

Jan Vierendeels; Bart Merci; Erik Dick

2003-01-01

294

Antimicrobial potential of Ricinus communis leaf extracts in different solvents against pathogenic bacterial and fungal strains  

PubMed Central

Objective To investigate the in vitro antimicrobial activities of the leaf extract in different solvents viz., methanol, ethanol and water extracts of the selected plant Ricinus communis. Methods Agar well diffusion method and agar tube dilution method were carried out to perform the antibacterial and antifungal activity of methanol, ethanol and aqueous extracts. Results Methanol leaf extracts were found to be more active against Gram positive bacteria (Bacillus subtilis: ATCC 6059 and Staphylococcus aureus: ATCC 6538) as well as Gram negative bacteria (Pseudomonas aeruginosa: ATCC 7221 and Klebsiella pneumoniae) than ethanol and aqueous leaf extracts. Antifungal activity of methanol and aqueous leaf extracts were also carried out against selected fungal strains as Aspergillus fumigatus and Aspergillus flavus. Methanolic as well as aqueous leaf extracts of Ricinus communis were effective in inhibiting the fungal growth. Conclusions The efficient antibacterial and antifungal activity of Ricinus communis from the present investigation revealed that the methanol leaf extracts of the selected plant have significant potential to inhibit the growth of pathogenic bacterial and fungal strains than ethanol and aqueous leaf extracts.

Naz, Rabia; Bano, Asghari

2012-01-01

295

Event-related potentials indicate different processes to mediate categorical and associative priming in person recognition.  

PubMed

Whether representations of people are stored in associative networks based on co-occurrence or are stored in terms of more abstract semantic categories is a controversial question. In the present study, participants performed fame decisions to unfamiliar or famous target faces (Experiment 1) or names (Experiment 2), which were primed, either by highly associated celebrity names or by names from the same occupational category, or were unprimed. Reaction times and event-related potentials (ERPs) were recorded. Reaction times yielded significant priming effects for both associated and same category conditions. ERPs to targets in the associated condition were significantly more positive than were ERPs in all other conditions over central and parietal areas (300-600 ms; N400 priming effect). By contrast, a more posterior effect was found for categorical priming. These findings held for both cross-domain (Experiment 1) and within-domain conditions (Experiment 2). Results (a) demonstrate behavioral and ERP evidence for categorical priming in person recognition, consistent with the assumption that shared semantic information units can mediate semantic priming, and (b) suggest that associative and categorical priming are based on mechanisms that are at least partially different. PMID:18763903

Wiese, Holger; Schweinberger, Stefan R

2008-09-01

296

Phytochemical screening, antioxidants and antimicrobial potential of Lantana camara in different solvents  

PubMed Central

Objective To evaluate the antioxidant activity, hydrogen peroxide radicals scavenging activity, reducing power, the total phenolic and flavonoids contents, and antimicrobial and antifungal activities of methanol, ethanol and water extracts of leaves of Lantana camara (L. camara). Methods Methanol, ethanol and water extracts were evaluated against four Gram positive and Gram negative bacterial isolates (Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Bacillus subtilis) and two fungal strains (Aspergillus fumigatus and Aspergillus flavus). Methanol extract at different concentrations was tested for antioxidant potential and phytochemicals were determined by using spectrophotometric method. Results The total phenolic content was (40.859±0.017) mg gallic acid/g in the leaves of L. camara, while the total flavonoids was (53.112±0.199) mg/g dry weight. Methanol leaf extract of L. camara showed maximum antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa and was also effective against other bacterial strains as compared to ethanol and aqueous extracts of leaves. The methanol leaf extract of L. camara exhibited significant inhibition (71%) and (66%) against Aspergillus fumigatus and Aspergillus flavus respectively. Conclusions The methanol extract of the L. camara leaves is effective against selected bacterial and fungal strains. Its phytochemical contents have broad antimicrobial properties and the plant might be a novel source of antimicrobial drug.

Naz, Rabia; Bano, Asghari

2013-01-01

297

Frequency of subthreshold oscillations at different membrane potential voltages in neurons at different anatomical positions on the dorsoventral axis in the rat medial entorhinal cortex.  

PubMed

Neurons from layer II of the medial entorhinal cortex show subthreshold membrane potential oscillations (SMPOs) which could contribute to theta-rhythm generation in the entorhinal cortex and to generation of grid cell firing patterns. However, it is unclear whether single neurons have a fixed unique oscillation frequency or whether their frequency varies depending on the mean membrane potential in a cell. We therefore examined the frequency of SMPOs at different membrane potentials in layer II stellate-like cells of the rat medial entorhinal cortex in vitro. Using whole-cell patch recordings, we found that the fluctuations in membrane potential show a broad band of low power frequencies near resting potential that transition to more narrowband oscillation frequencies with depolarization. The transition from broadband to narrowband frequencies depends on the location of the neuron along the dorsoventral axis in the entorhinal cortex, with dorsal neurons transitioning to higher-frequency oscillations relative to ventral neurons transitioning to lower-frequency oscillations. Once SMPOs showed a narrowband frequency, systematic frequency changes were not observed with further depolarization. Using a Hodgkin-Huxley-style model of membrane currents, we show that differences in the influence of depolarization on the frequency of SMPOs at different dorsal to ventral positions could arise from differences in the properties of the h current. The properties of frequency changes in this data are important for evaluating models of the generation of grid cell firing fields with different spacings along the dorsal-to-ventral axis of medial entorhinal cortex. PMID:21880929

Yoshida, Motoharu; Giocomo, Lisa M; Boardman, Ian; Hasselmo, Michael E

2011-08-31

298

Linkages between microbial functional potential and wastewater constituents in large-scale membrane bioreactors for municipal wastewater treatment.  

PubMed

Large-scale membrane bioreactors (MBRs) have been widely used for the municipal wastewater treatment, whose performance relies on microbial communities of activated sludge. Nevertheless, microbial functional structures in MBRs remain little understood. To gain insight into functional genes and their steering environmental factors, we adopted GeoChip, a high-throughput microarray-based tool, to examine microbial genes in four large-scale, in-operation MBRs located in Beijing, China. The results revealed substantial microbial gene heterogeneity (43.7-85.1% overlaps) among different MBRs. Mantel tests indicated that microbial nutrient cycling genes were significantly (P < 0.05) correlated to influent COD, [Formula: see text] -N, TP or sulfate, which signified the importance of microbial mediation of wastewater constituent removal. In addition, functional genes shared by all four MBRs contained a large number of genes involved in antibiotics resistance, metal resistance and organic remediation, suggesting that they were required for degradation or resistance to toxic compounds in wastewater. The linkages between microbial functional structures and environmental variables were also unveiled by the finding of hydraulic retention time, influent COD, [Formula: see text] -N, mixed liquid temperature and humic substances as major factors shaping microbial communities. Together, the results presented demonstrate the utility of GeoChip-based microarray approach in examining microbial communities of wastewater treatment plants and provide insights into the forces driving important processes of element cycling. PMID:24675272

Sun, Yanmei; Shen, Yue-xiao; Liang, Peng; Zhou, Jizhong; Yang, Yunfeng; Huang, Xia

2014-06-01

299

A large prospective study of meat consumption and colorectal cancer risk: an investigation of potential mechanisms underlying this association  

PubMed Central

Although the relation between red and processed meat intake and colorectal cancer has been reported in several epidemiologic studies, very few investigated the potential mechanisms. This study examined multiple potential mechanisms in a large U.S. prospective cohort with a detailed questionnaire on meat type and meat cooking methods linked to databases for estimating intake of mutagens formed in meats cooked at high temperatures (heterocyclic amines, polycyclic aromatic hydrocarbons), heme iron, nitrate and nitrite. During 7 years of follow-up, 2,719 colorectal cancer cases were ascertained from a cohort of 300,948 men and women. The hazard ratios (HR) and 95% confidence intervals (CI) comparing the fifth to the first quintile for both red (HR=1.24, 95% CI: 1.09-1.42; p-trend <0.001) and processed meat (HR=1.16, 95% CI: 1.01-1.32; p-trend=0.017) intake indicated an elevated risk for colorectal cancer. The potential mechanisms for this relation include heme iron (HR=1.13, 95% CI: 0.99-1.29; p-trend=0.022), nitrate from processed meats (HR=1.16, 95% CI: 1.02-1.32; p-trend=0.001) and heterocyclic amine intake (HR=1.19, 95% CI: 1.05-1.34; p-trend <0.001 for MeIQx and HR=1.17, 95% CI: 1.05-1.29; p-trend <0.001 for DiMeIQx). In general, the elevated risks were higher for rectal cancer than for colon cancer, with the exception of MeIQx and DiMeIQx, which were only associated with colon cancer. In conclusion, we found a positive association for red and processed meat intake and colorectal cancer; heme iron, nitrate/nitrite, and heterocyclic amines from meat may explain these associations.

Cross, Amanda J.; Ferrucci, Leah M.; Risch, Adam; Graubard, Barry I .; Ward, Mary H.; Park, Yikyung; Hollenbeck, Albert R.; Schatzkin, Arthur; Sinha, Rashmi

2010-01-01

300

Genome Sequencing of Listeria monocytogenes "Quargel" Listeriosis Outbreak Strains Reveals Two Different Strains with Distinct In Vitro Virulence Potential  

PubMed Central

A large listeriosis outbreak occurred in Austria, Germany and the Czech Republic in 2009 and 2010. The outbreak was traced back to a traditional Austrian curd cheese called “Quargel” which was contaminated with two distinct serovar 1/2a Listeria monocytogenes strains (QOC1 and QOC2). In this study we sequenced and analysed the genomes of both outbreak strains in order to investigate the extent of genetic diversity between the two strains belonging to MLST sequence types 398 (QOC2) and 403 (QOC1). Both genomes are highly similar, but also display distinct properties: The QOC1 genome is approximately 74 kbp larger than the QOC2 genome. In addition, the strains harbour 93 (QOC1) and 45 (QOC2) genes encoding strain-specific proteins. A 21 kbp region showing highest similarity to plasmid pLMIV encoding three putative internalins is integrated in the QOC1 genome. In contrast to QOC1, strain QOC2 harbours a vip homologue, which encodes a LPXTG surface protein involved in cell invasion. In accordance, in vitro virulence assays revealed distinct differences in invasion efficiency and intracellular proliferation within different cell types. The higher virulence potential of QOC1 in non-phagocytic cells may be explained by the presence of additional internalins in the pLMIV-like region, whereas the higher invasion capability of QOC2 into phagocytic cells may be due to the presence of a vip homologue. In addition, both strains show differences in stress-related gene content. Strain QOC1 encodes a so-called stress survival islet 1, whereas strain QOC2 harbours a homologue of the uncharacterized LMOf2365_0481 gene. Consistently, QOC1 shows higher resistance to acidic, alkaline and gastric stress. In conclusion, our results show that strain QOC1 and QOC2 are distinct and did not recently evolve from a common ancestor.

Rychli, Kathrin; Muller, Anneliese; Zaiser, Andreas; Schoder, Dagmar; Allerberger, Franz; Wagner, Martin; Schmitz-Esser, Stephan

2014-01-01

301

Electromagnetic phase differences in the coherent backscattering enhancement mechanism for random media consisting of large nontransparent spheres.  

PubMed

Phase curves of intensity are calculated for light scattering in media randomly packed with large nontransparent spheres (x=125), the surfaces of which reflect according to the Fresnel equations. We consider three values of refractive index: m = 0.73 + i5.93 (metal Al), 1.6 + i1.72 (metal Fe), and 1.5 + i0.1 (black glass). We use a Monte Carlo ray-tracing approach. Different kinds of electromagnetic phase differences of reciprocal trajectories are investigated for the second and third orders of scattering; the highest orders give comparatively small contributions due to the backward-scattering indicatrix of large nontransparent spheres. We find that the main electromagnetic phase difference between the direct and time-reversal (reciprocal) trajectories is the outer phase difference that depends only on the relative positions of the first and last points of the ray reflections and the phase angle. The inner phase difference is connected with the changing path length of the ray inside the medium. This depends on the particle size and the phase angle that is the angle between the source and receiver from the scatterer, i.e., 180 degrees minus the scattering angle. The inner phase difference can give oscillations in the phase curve consisting of second-order components if the medium consists of strictly monodisperse spheres. Usually the coherent backscattering enhancement is calculated ignoring the shadow-hiding effect. We show that accounting for the shadowing of the reciprocal trajectory is important for the formation of the backscattering effect. The third-order scattering surge is a superposition of wide and narrow opposition spikes that correspond to two different types of scattering trajectories, closed and opened ones. The first type is due to scattering by two particles; the second one corresponds to scattering by three particles. PMID:17334449

Stankevich, Dmitriy; Istomina, Larissa; Shkuratov, Yuriy; Videen, Gorden

2007-03-20

302

Onset Dynamics of Action Potentials in Rat Neocortical Neurons and Identified Snail Neurons: Quantification of the Difference  

Microsoft Academic Search

The generation of action potentials (APs) is a key process in the operation of nerve cells and the communication between neurons. Action potentials in mammalian central neurons are characterized by an exceptionally fast onset dynamics, which differs from the typically slow and gradual onset dynamics seen in identified snail neurons. Here we describe a novel method of analysis which provides

Maxim Volgushev; Aleksey Malyshev; Pavel Balaban; Marina Chistiakova; Stanislav Volgushev; Fred Wolf; Huibert D. Mansvelder

2008-01-01

303

Inhibition and biotransformation potential of naphthenic acids under different electron accepting conditions.  

PubMed

Naphthenic acids (NAs) are a complex group of alkyl-substituted acyclic, monocyclic and polycyclic carboxylic acids present in crude oil, oil sands process water and tailings ponds, as well as in refinery wastewater. Bioassays were performed to investigate the biotransformation potential and inhibitory effect of a commercial NA mixture to nitrification, denitrification and fermentation/methanogenesis using mixed cultures not previously exposed to NAs. NAs inhibited nitrification in a mixed aerobic heterotrophic/nitrifying culture at concentrations as low as 80 mg NA/L, whereas, an enriched nitrifying culture was only affected at 400 mg NA/L. The lower nitrification inhibition in the latter assay is attributed to the higher population size of nitrosofying and nitrifying bacteria compared to the mixed heterotrophic/nitrifying culture. The NA mixture was not inhibitory to denitrifiers up to 400 mg/L. At higher NA concentrations, cell lysis was pronounced and lysis products were the main source of degradable carbon driving denitrification in culture series prepared without an external carbon source. In the presence of a degradable external carbon source, no difference was observed in nitrate reduction rates or nitrogen gas production at all NA concentrations tested. Methanogenesis was completely inhibited at NA concentrations equal to or higher than 200 mg/L. Methanogenic culture series amended with 80 mg NA/L were transiently inhibited and methane production in culture series prepared with NAs and an external carbon source or NAs only recovered in 136 and 41 days, respectively. Accumulation of volatile fatty acids was observed at inhibitory NA concentrations; however, carbon dioxide production was not affected by NAs, indicating that fermentation and acidogenesis were not affected by NAs. NAs were not degraded under nitrate-reducing or fermentative/methanogenic conditions used in the present study, regardless of the presence or not of another, degradable carbon/energy source. PMID:23134740

Misiti, Teresa; Tandukar, Madan; Tezel, Ulas; Pavlostathis, Spyros G

2013-01-01

304

Floating potential of a small particle in a plasma: Difference between Maxwellian and Druyvesteyn electron velocity distributions  

SciTech Connect

The floating potential of a small spherical particle immersed in a plasma is calculated for two different electron velocity distributions functions, Maxwellian and Druyvesteyn ones. It is shown that for plasma conditions typical for laboratory gas discharges, the difference between the floating potentials for these two distributions is small, provided the mean energy of the electrons is the same. The obtained results can be useful in the context of complex (dusty) plasmas.

Khrapak, Sergey [Max-Planck-Institut fuer Extraterrestrische Physik, D-85741 Garching (Germany) and Joint Institute for High Temperatures, 125412 Moscow (Russian Federation)

2010-10-15

305

Observations of Coastal IO Emissions on the Southern Hemisphere and Emission Potential of Different Seaweed Species  

NASA Astrophysics Data System (ADS)

At coastal sites reactive iodine species emitted by seaweed in the intertidal zone during low tide are known to have an important influence on the atmospheric chemistry. However, many underlying mechanisms are presently not understood. Also coastal studies were focused on a few locations on the northern hemisphere and their predominant seaweed species laminaria digitata and ascophyllum nodosum. Therefore the spatial emission and extent of the areas where halogen chemistry is of importance needs to be much better quantified. Especially in the mid latitudes of the southern hemisphere RHS measurements are very sparse. Here we report the first observations of coastal iodine monoxide (IO) in the southern hemisphere during the HALMA/MAORI campaign which was carried out in February to March 2013 on the east coast of New Zealand's South Island at Shag Point located north of Dunedin. To detect IO we used a mobile Open Light Path Cavity Enhanced Differential Optical Absorption Spectroscopy (CE-DOAS) instrument and a stationary Long Path (LP)-DOAS Instrument, which was furthermore used to measure BrO, O3 and I2. The measurement path was positioned over the water and mainly measured air masses that only passes over submerged seaweed forests. With the CE-DOAS placed close to exposed seaweed patches (mainly Macrocystis Pyrifera) we were able to observe high IO mixing ratios of up to 50 ppt (2ppt detection limit). However, the LP-DOAS did not detect IO above the detection limit of 0.7 ppt. This is consistent with previous observations which found that seaweed only emits halogens when exposed to air. To further investigate the emission potential of the seaweed species we setup a Teflon chamber around the CE-DOAS and measured the emissions of five different species for several hours. Additionally the air in the chamber was probed by a compact gas chromatograph (?DIRAC) for measurements of halocarbons and a TEI Ozone monitor. We found very high IO mixing ratios of up to 500 ppt for four seaweed species which correlated with high levels of halocarbons (CH3I, CH2Br2, CH2BrI and CH2BrCl up to 100ppt, CHBr3 up to 600ppt). These results, the similarities and differences in the emission behavior and implications for atmospheric chemistry are discussed.

Horbanski, Martin; Schmitt, Stefan; Frieß, Udo; Pöhler, Denis; Johnston, Paul; Kreher, Karin; Robinson, Andrew D.; Thomas, Alan; Harris, Neil R. P.; Platt, Ulrich

2014-05-01

306

A multi-resolution strategy for a multi-objective deformable image registration framework that accommodates large anatomical differences  

NASA Astrophysics Data System (ADS)

Currently, two major challenges dominate the field of deformable image registration. The first challenge is related to the tuning of the developed methods to specific problems (i.e. how to best combine different objectives such as similarity measure and transformation effort). This is one of the reasons why, despite significant progress, clinical implementation of such techniques has proven to be difficult. The second challenge is to account for large anatomical differences (e.g. large deformations, (dis)appearing structures) that occurred between image acquisitions. In this paper, we study a framework based on multi-objective optimization to improve registration robustness and to simplify tuning for specific applications. Within this framework we specifically consider the use of an advanced model-based evolutionary algorithm for optimization and a dual-dynamic transformation model (i.e. two "non-fixed" grids: one for the source- and one for the target image) to accommodate for large anatomical differences. The framework computes and presents multiple outcomes that represent efficient trade-offs between the different objectives (a so-called Pareto front). In image processing it is common practice, for reasons of robustness and accuracy, to use a multi-resolution strategy. This is, however, only well-established for single-objective registration methods. Here we describe how such a strategy can be realized for our multi-objective approach and compare its results with a single-resolution strategy. For this study we selected the case of prone-supine breast MRI registration. Results show that the well-known advantages of a multi-resolution strategy are successfully transferred to our multi-objective approach, resulting in superior (i.e. Pareto-dominating) outcomes.

Alderliesten, Tanja; Bosman, Peter A. N.; Sonke, Jan-Jakob; Bel, Arjan

2014-03-01

307

On the origin of the electrostatic potential difference at a liquid-vacuum interface.  

PubMed

The microscopic origin of the interface potential calculated from computer simulations is elucidated by considering a simple model of molecules near an interface. The model posits that molecules are isotropically oriented and their charge density is Gaussian distributed. Molecules that have a charge density that is more negative toward their interior tend to give rise to a negative interface potential relative to the gaseous phase, while charge densities more positive toward their interior give rise to a positive interface potential. The interface potential for the model is compared to the interface potential computed from molecular dynamics simulations of the nonpolar vacuum-methane system and the polar vacuum-water interface system. The computed vacuum-methane interface potential from a molecular dynamics simulation (-220 mV) is captured with quantitative precision by the model. For the vacuum-water interface system, the model predicts a potential of -400 mV compared to -510 mV, calculated from a molecular dynamics simulation. The physical implications of this isotropic contribution to the interface potential is examined using the example of ion solvation in liquid methane. PMID:19102551

Harder, Edward; Roux, Benoît

2008-12-21

308

A model potential for the internal rotation of nitrosyl hyperfluorite. A comparative analysis of different theoretical methods  

NASA Astrophysics Data System (ADS)

We present a comparative analysis of the internal rotation energy curves of nitrosyl hyperfluorite (FO?NO). Two model potentials, derived from a Fourier series expansion, have been used to rationalize the trans?cis isomerization process for different theoretical methods going from traditional molecular orbital calculations to density functional theory. It is shown that Hartree—Fock (HF) and post Hartree—Fock (pHF) calculations, using a sufficiently large basis set, lead to results that are qualitatively similar. However, local density functional (LDF) calculations produce results that are not compatible. The resulting barrier heights vary from 2.36 (LDF) to 12.76 kcal/mol (MP4SDTQ/6-31G*) passing through a value of 8.33 kcal/mol from a HF/6-31G calculations. It is concluded that the LDF results, within the approximations used in that calculation, appear to be anomalous when compared to the HF and pHF results.

Cárdenas-Jirón, Gloria I.; Toro-Labbé, Alejandro

1994-05-01

309

Striking phenotypic and functional differences in lamina propria lymphocytes from the large and small intestine of mice.  

PubMed

Although intraepithelial T lymphocytes of the large intestine (LI) are known to differ from those of the small intestine (SI) in phenotype and function, differences in LI and SI lamina propria (LP) lymphocyte populations have not been clearly established. In this work we found striking phenotypic differences between SI and LI LP lymphocyte populations from Balb/c mice analyzed by flow cytometry. In the LI most lymphocytes were B cells and the predominant T cells were TCR-alpha beta+, CD8+. In contrast, in the SI most T lymphocytes were CD4+ expressing TCR-alpha beta+, although a higher proportion expressed TCR-gamma delta+ than in the LI. In T cells the expression of adhesion molecules and cytokines was also different between SI and LI. The proportion of LP T cells expressing alpha4beta7 and L-selectin was higher in the LI than in the SI; whereas a greater proportion of cells expressing alpha(E)beta7 were detected in the SI than in LI. Higher proportions of T cells expressing L-selectin and alpha4beta1 were detected in the intraepithelial compartment of the LI than that of the SI, whereas the number of T cells expressing alpha(E)beta7 was much higher in the SI than in the LI. The proportion of T cells spontaneously producing IL-2, IFN gamma, and IL-4 at the intraepithelial and lamina propria, in the small and large intestine, was different indicating that distinctive functional features exist in the lymphocyte populations residing at the different intestinal compartments. PMID:15808880

Reséndiz-Albor, Aldo Arturo; Esquivel, Rita; López-Revilla, Rubén; Verdín, Leticia; Moreno-Fierros, Leticia

2005-04-29

310

On the differences in element abundances of energetic ions from corotating events and from large solar events  

NASA Technical Reports Server (NTRS)

The abundances of energetic ions accelerated from high-speed solar wind streams by shock waves formed at corotating interaction regions (CIRs) where high-speed streams overtake the lower-speed solar wind are examined. The observed element abundances appear to represent those of the high-speed solar wind, unmodified by the shock acceleration. These abundances, relative to those in the solar photosphere, are organized by the first ionization potential (FIP) of the ions in a way that is different from the FIP effect commonly used to describe differences between abundances in the solar photosphere and those in the solar corona, solar energetic particles (SEPs), and the low-speed solar wind. In contrast, the FIP effect of the ion abundances in the CIR events is characterized by a smaller amplitude of the differences between high-FIP and low-FIP ions and by elevated abundances of He, C, and S.

Reames, D. V.; Richardson, I. G.; Barbier, L. M.

1991-01-01

311

A Large-Scale Investigation of Lateralization in Cortical Anatomy and Word Reading: Are There Sex Differences?  

PubMed Central

Although left hemisphere language specialization is one of the most widely reported findings in human neuropsychology, some studies have found evidence for more bilateral language organization in women. We report findings of a large scale, multi-task investigation of sex differences in both structural asymmetries and lateralization of word reading. Two hundred participants were tested in eight divided visual field lexical tasks, and each received a structural MRI scan. We examined whether there was evidence for sex differences in overall measures of neuroanatomical and behavioral lateralization, in specific language tasks and brain regions, and in variation in asymmetry within and across tasks and brain regions. There was very little evidence for sex differences on any behavioral measure. The few indications of sex differences in the current report accounted for 2% or less of the individual variation in asymmetry and could not be replicated in independent subsamples. No sex differences were observed in the asymmetry of structures in Broca’s and Wernicke’s area such as pars triangularis, pars opercularis, the planum temporale, planum parietale, or Heschl’s gyrus. There were also no sex differences in the variability of neuroanatomical asymmetries within or between brain regions. However, a significant relationship between planum temporale and behavioral asymmetry was restricted to men.

Chiarello, Christine; Welcome, Suzanne E.; Halderman, Laura K.; Towler, Stephen; Julagay, Janelle; Otto, Ronald; Leonard, Christiana M.

2011-01-01

312

One-dimensional modeling of a recent Ganga avulsion: Assessing the potential effect of tectonic subsidence on a large river  

NASA Astrophysics Data System (ADS)

River avulsion as studied in small-sized and medium-sized rivers is partly explained by the water surface gradient advantage of a new channel course over the old course, caused by spatial differences in aggradation and compaction. Recently, the effect of meandering upstream of the avulsion node, or bifurcation, was shown to have an equally large effect on avulsion duration as gradient advantage. These effects remain poorly understood for the largest rivers on Earth, where gradients are very small, subtle gradient advantages are affected by tectonics, and often several anabranches remain active simultaneously. Our objective was to assess the relative importance of these factors in the River Ganga in determining the pacing of an avulsion. We used a combination of historical data, remote sensing, and one-dimensional modeling. The course of the Ganga in historical times was through the present Ganga–Bhagirathi system but then there was either a gradual or sudden shift to the present Ganga–Padma system. Historical evidence and remnant paleochannels, as observed in satellite sensor data, corroborate the changing pattern of the Ganga River system, but the exact causes of the shifting and of the short avulsion duration remain unclear. Based on generalized data, using a one-dimensional model we ran idealized scenarios bracketing different tectonic subsidence estimates for long-term morphodynamic evolution of the upstream channel and the two downstream bifurcates. The model predicts flow and sediment partitioning at the bifurcation node, and includes the effect of migrating meanders at the bifurcation and width adjustment of the bifurcates. Our modeling demonstrates that the old and the new branches can remain 'open' and morphologically active for a long time because of the large backwater effect and the high mobility of the sediment. The bifurcation stabilizes at an asymmetrical flow and sediment division, which in smaller rivers (such as the River Rhine) would be followed by residual channel filling but in the much larger Ganges results in morphologically active anabranches. The model results reveal that neither a gradient advantage nor a bend upstream of the bifurcation leads to an avulsion within centuries as has been observed in some large rivers in tectonically inactive regions. On the other hand, a realistic tectonic uplift of the old branch or subsidence of the new branch may force an avulsion to take place quickly, and historical data show that the study area is seismically active. The combination of these factors leads to a realistic modeled avulsion duration of less than three centuries. Historical data indicate that these general conclusions might also apply to other large rivers in this region, e.g. the Brahmaputra and the Teesta. We conclude that large rivers may avulse quickly in response to tectonics but attain an anabranching pattern because of the large dimension of the residual channel and backwater effects.

Gupta, Niladri; Kleinhans, Maarten G.; Addink, Elisabeth A.; Atkinson, Peter M.; Carling, Paul A.

2014-05-01

313

Potential Effects of Climate Change on the Water Level, Flora and Macro-fauna of a Large Neotropical Wetland  

PubMed Central

Possible consequences of climate change in one of the world’s largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades.

Ubeda, Barbara; Di Giacomo, Adrian S.; Neiff, Juan Jose; Loiselle, Steven A.; Guadalupe Poi, Alicia S.; Galvez, Jose Angel; Casco, Silvina; Cozar, Andres

2013-01-01

314

Potential effects of climate change on the water level, flora and macro-fauna of a large neotropical wetland.  

PubMed

Possible consequences of climate change in one of the world's largest wetlands (Ibera, Argentina) were analysed using a multi-scale approach. Climate projections coupled to hydrological models were used to analyse variability in wetland water level throughout the current century. Two potential scenarios of greenhouse gas emissions were explored, both resulting in an increase in the inter-annual fluctuations of the water level. In the scenario with higher emissions, projections also showed a long-term negative trend in water-level. To explore the possible response of biota to such water-level changes, species-area relationships of flora and aerial censuses of macro-fauna were analysed during an extraordinary dry period. Plant species richness at the basin scale was found to be highly resistant to hydrological changes, as the large dimension of the wetland acts to buffer against the water-level variations. However, local diversity decreased significantly with low water levels, leading to the loss of ecosystem resilience to additional stressors. The analysis of macro-fauna populations suggested that wetland provides refuge, in low water periods, for the animals with high dispersal ability (aquatic and migratory birds). On the contrary, the abundance of animals with low dispersal ability (mainly herbivorous species) was negatively impacted in low water periods, probably because they are required to search for alternative resources beyond the wetland borders. This period of resource scarcity was also related to increased mortality of large mammals (e.g. marsh deer) around water bodies with high anthropogenic enrichment and cyanobacteria dominance. The synergy between recurrent climatic fluctuations and additional stressors (i.e. biological invasions, eutrophication) presents an important challenge to the conservation of neotropical wetlands in the coming decades. PMID:23874446

Úbeda, Bárbara; Di Giacomo, Adrian S; Neiff, Juan José; Loiselle, Steven A; Poi, Alicia S Guadalupe; Gálvez, José Ángel; Casco, Silvina; Cózar, Andrés

2013-01-01

315

Shallow Megathrust Rupture Propagation of Some Large and Giant Earthquakes: Its Tsunami Potential and Identification from Spectral Energy Content  

NASA Astrophysics Data System (ADS)

Rare, slow-rupturing tsunami earthquakes are known to occur in the shallowest megathrust environment that both slows rupture propagation and enhances tsunami potential, while other megathrust earthquakes remain deeper, rupturing more rapidly and having reduced tsunami potential due to diminished vertical seafloor displacement. However, we postulate that the massive transoceanic tsunamis of some giant earthquakes are caused by total megathrust rupture, where coseismic slip extends beyond the normal seismogenic range, and into the near-trench tsunami earthquake environment. Such ruptures drastically enhance seafloor excitation and causing massive tsunami generation. Examples include the 2004 MW 9.1 Sumatran, the 1964 MW 9.2 Alaskan, and the 1960 MW 9.5 Chile earthquakes. For recent events, the spatial extent of rupture into the near-trench is observable through seismologic modeling of fault rupture, and the distribution of early aftershocks. An ideal case-example supporting this hypothesis is the clear change in shallow rupture behavior between the 2004 MW 9.1 and 2005 MW 8.7 Sumatran earthquakes, with the latter reaming deeper and having only modest tsunami excitation. We find that through examination of the rupture energy of recent very large earthquakes we can identify rupture that pervades the shallow trench by the event’s relative deficiency in high-frequency radiated seismic energy, similar to tsunami earthquakes. Testing both bulk spectral energy ratios, and deviations in the high-frequency energy growth during rupture, we identify the Sumatran 2004 event as deficient, while the 2005 Sumatran and 2010 Chile earthquakes appear in the normal range similar to smaller events, identifying them as having normal megathrust ruptures. Unlike finite-fault modeling using seismic waveforms and imaging of early aftershocks, which can also identify near-trench rupture, earthquake energy determinations can be made in near real-time (often within 10 minutes of rupture initiation), making it a useful tool for rapid tsunami hazard assessment.

Newman, A. V.; Convers, J. A.

2010-12-01

316

Addressing Students' Difficulties in Understanding Two Different Expressions of Gravitational Potential Energy (I): mgh & -GMm/r  

NSDL National Science Digital Library

During our investigation of students' understanding of gravitational potential energy, we found some difficulties that students have with this topic. Many students who took upper-level mechanics courses had difficulties in understanding why there are two different expressions of gravitational potential energy. These students said they had some difficulties in understanding why there should be two different signs (+ & ?) and two different forms (g & 1/r) even though these expressions were considered as representing the same gravitational potential energy. To gain understanding of the sources of student difficulties, we used weekly reports and individual interviews. We analyzed student difficulties in terms of conceptual knowledge, procedural knowledge, and contextual knowledge. The results of these research have guided the development of teaching material that addresses students' difficulties in understanding gravitational potential energy. We will show the development process and contents of the material in the second paper on this topic.

Lee, Gyoungho; Yi, Jinseog

2007-11-25

317

Production of very high potential differences by intracloud lightning discharges in connection with terrestrial gamma ray flashes  

NASA Astrophysics Data System (ADS)

Terrestrial gamma-ray flashes (TGFs) have been correlated with an early development stage of high altitude positive intracloud (+IC) flashes in which the negative leader propagates up toward the upper positive charge region, while the positive leader propagates down toward the lower negative charge region. The resultant bidirectional leaders develop electrical potential differences in the vicinity of their heads with respect to the ambient potential distribution created by the thundercloud charges. These potential differences are believed to be of essential importance for the generation of TGFs. Using electrostatic calculations and a three-dimensional Cartesian fractal model, we quantify these potential differences produced in a developing +IC lightning discharge for given thunderstorm electric configurations. We present a case of a +IC lightning discharge in a realistic thunderstorm configuration that leads to a very high (˜300 MV) potential difference and show how a delay in the development of the negative leader with respect to the positive one in a bidirectional leader system can facilitate a high potential difference in the negative leader head region.

Mallios, Sotirios A.; Celestin, Sebastien; Pasko, Victor P.

2013-02-01

318

Water flow measurement in large bore pipes: an experimental comparison between two different types of insertion flowmeters.  

PubMed

In this paper the metrological behavior of two different insertion flowmeters (magnetic and turbine types) in large water pipes is described. A master-slave calibration was carried out in order to estimate the overall uncertainty of the tested meters. The experimental results show that (i) the magnetic insertion tested flowmeter performs the claimed accuracy (+/- 2%) within all the flow range (20:1); (ii) the insertion turbine tested meter, instead, reaches the claimed accuracy just in the upper zone of the flow range. PMID:12708537

Cascetta, Furio; Palombo, Adolfo; Scalabrini, Gianfranco

2003-04-01

319

Geographic Differences in Potentially Preventable Readmission Rates in Rural and Urban Hospitals. Final Report No. 12.  

National Technical Information Service (NTIS)

Potentially preventable hospital readmissions (PPRs) among Medicare patients are examples of inefficiencies in the health care system. Policymakers are considering efforts to measure and publicly report preventable readmission rates and target hospitals w...

A. Knudson K. Muus M. G. Klug

2010-01-01

320

[Evaluation efficiency of different bioassay methods on allelopathic potential of Oryza sativa].  

PubMed

In this paper, three bioassay methods, i.e., relay seeding in agar (RSA), relay seeding in silica (RSS) and seeding in rice root-exudation (SRE), were used to test the allelopathic potential of 8 rice cultivars on the target weed barnyardgrass (Echinochloa crusgalli). The results indicated that RSA was the ideal method for the bioassay, showing the highest efficiency in the evaluation of allelopathic potential. RSS and SRE had a lower efficiency than RSA, but these two methods showed the same tendency in evaluating the allelopathic potential of rice. RSA, the considered best bioassay method in this experiment, was used for 57 allelopathic rice germplasm screening, and 5 of them, i.e., Iguape Cateto, PI312777, Azucena, Taichung Native 1 and IAC25 performed the strongest allelopathic potential in the suppression on barnyardgrass. PMID:15669487

Shen, Lihua; Liang, Yiyuan; He, Huaqin; He, Jun; Liang, Kangjing; Lin, Wenxiong

2004-09-01

321

Altitude Distribution of the Auroral Acceleration Potential Determined from Cluster Satellite Data at Different Heights  

SciTech Connect

Aurora, commonly seen in the polar sky, is a ubiquitous phenomenon occurring on Earth and other solar system planets. The colorful emissions are caused by electron beams hitting the upper atmosphere, after being accelerated by quasistatic electric fields at 1-2 R{sub E} altitudes, or by wave electric fields. Although aurora was studied by many past satellite missions, Cluster is the first to explore the auroral acceleration region with multiprobes. Here, Cluster data are used to determine the acceleration potential above the aurora and to address its stability in space and time. The derived potential comprises two upper, broad U-shaped potentials and a narrower S-shaped potential below, and is stable on a 5 min time scale. The scale size of the electric field relative to that of the current is shown to depend strongly on altitude within the acceleration region. To reveal these features was possible only by combining data from the two satellites.

Marklund, Goeran T.; Sadeghi, Soheil; Karlsson, Tomas; Lindqvist, Per-Arne [Space and Plasma Physics, School of Electrical Engineering, KTH, SE 10044 Stockholm (Sweden); Nilsson, Hans [Swedish Institute of Space Physics, Box 812, SE 981 28 Kiruna (Sweden); Forsyth, Colin; Fazakerley, Andrew [Mullard Space Science Laboratory, University College, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom); Lucek, Elizabeth A. [Space and Atmospheric Physics Group, Blacket Laboratory, Imperial College, London (United Kingdom); Pickett, Jolene [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242-1479 (United States)

2011-02-04

322

The potential use of allogeneic platelet-rich plasma for large bone defect treatment: immunogenicity and defect healing efficacy.  

PubMed

Autologous platelet-rich plasma (PRP) has been extensively investigated for large bone defect treatment, but its clinical application is harassed by controversial outcome, due to highly variable PRP quality among patients. Alternatively, allogeneic PRP from well-characterized donors cannot only generate more consistent and reliable therapeutic effect but also avoid harvesting large quantities of blood, an additional health burdens to patients. However, the use of allogeneic PRP for bone defect treatment is generally less investigated, especially for its immunogenicity in such application. Here, we meticulously investigated the immunogenicity of allogeneic PRP and evaluated its healing efficacy for critical-sized defect treatment. Allogeneic PRP contained 4.1-fold and 2.7- to 4.9-fold higher amount of platelets and growth factors than whole blood, respectively. The intramuscular injection of allogeneic PRP to rabbits did not trigger severe and chronic immunoresponse, evidenced by little change in muscular tissue microstructure and CD4?/CD8? T lymphocyte subpopulation in peripheral blood. The implantation of allogeneic PRP/deproteinized bone matrix (DPB) constructs (PRP+DPB) successfully bridged 1.5-cm segmental radial defects in rabbits, achieving similar healing capacity as autologous MSC/DPB constructs (MSC+DPB), with greater bone formation (1.1-1.5×, p<0.05) and vascularization (1.3-1.6×, p<0.05) than DPB alone, shown by histomorphometric analysis, bone mineral density measurement, and radionuclide bone imaging. Furthermore, the implantation of both allogeneic PRP- and autologous MSC-mediated DPB constructs (PRP + MSC + DPB) resulted in the most robust bone regeneration (1.2-2.1×, p<0.05) and vascularization (1.3-2.0×, p<0.05) than others (PRP+DPB, MSC+DPB, or DPB alone). This study has demonstrated the promising use of allogeneic PRP for bone defect treatment with negligible immunogenicity, great healing efficacy, potentially more consistent quality, and no additional health burden to patients; additionally, the synergetic enhancing effect found between allogeneic PRP and autologous MSCs may shed a light on developing new therapeutic strategies for large bone defect treatment. PMID:22863146

Zhang, Zhi-Yong; Huang, Ai-Wen; Fan, Jun Jun; Wei, Kuanhai; Jin, Dan; Chen, Bin; Li, Dan; Bi, Long; Wang, Jun; Pei, Guoxian

2013-01-01

323

Cytoskeletal stiffness, friction, and fluidity of cancer cell lines with different metastatic potential.  

PubMed

We quantified mechanical properties of cancer cells differing in metastatic potential. These cells included normal and H-ras-transformed NIH3T3 fibroblast cells, normal and oncoprotein-overexpressing MCF10A breast cancer cells, and weakly and strongly metastatic cancer cell line pairs originating from human cancers of the skin (A375P and A375SM cells), kidney (SN12C and SN12PM6 cells), prostate (PC3M and PC3MLN4 cells), and bladder (253J and 253JB5 cells). Using magnetic twisting cytometry, cytoskeletal stiffness (g') and internal friction (g?) were measured over a wide frequency range. The dependencies of g' and g? upon frequency were used to determine the power law exponent x which is a direct measure of cytoskeletal fluidity and quantifies where the cytoskeleton resides along the spectrum of solid-like (x = 1) to fluid-like (x = 2) states. Cytoskeletal fluidity x increased following transformation by H-ras oncogene expression in NIH3T3 cells, overexpression of ErbB2 and 14-3-3-? in MCF10A cells, and implantation and growth of PC3M and 253J cells in the prostate and bladder, respectively. Each of these perturbations that had previously been shown to enhance cancer cell motility and invasion are shown here to shift the cytoskeleton towards a more fluid-like state. In contrast, strongly metastatic A375SM and SN12PM6 cells that disseminate by lodging in the microcirculation of peripheral organs had smaller x than did their weakly metastatic cell line pairs A375P and SN12C, respectively. Thus, enhanced hematological dissemination was associated with decreased x and a shift towards a more solid-like cytoskeleton. Taken together, these results are consistent with the notion that adaptations known to enhance metastatic ability in cancer cell lines define a spectrum of fluid-like versus solid-like states, and the position of the cancer cell within this spectrum may be a determinant of cancer progression. PMID:22961212

Coughlin, Mark F; Bielenberg, Diane R; Lenormand, Guillaume; Marinkovic, Marina; Waghorne, Carol G; Zetter, Bruce R; Fredberg, Jeffrey J

2013-03-01

324

Water models based on a single potential energy surface and different molecular degrees of freedom  

NASA Astrophysics Data System (ADS)

Up to now it has not been possible to neatly assess whether a deficient performance of a model is due to poor parametrization of the force field or the lack of inclusion of enough molecular properties. This work compares several molecular models in the framework of the same force field, which was designed to include many-body nonadditive effects: (a) a polarizable and flexible molecule with constraints that account for the quantal nature of the vibration [B. Hess, H. Saint-Martin, and H. J. C. Berendsen, J. Chem. Phys. 116, 9602 (2002), H. Saint-Martin, B. Hess, and H. J. C. Berendsen, J. Chem. Phys. 120, 11133 (2004)], (b) a polarizable and classically flexible molecule [H. Saint-Martin, J. Hernández-Cobos, M. I. Bernal-Uruchurtu, I. Ortega-Blake, and H. J. C. Berendsen, J. Chem. Phys. 113, 10899 (2000)], (c) a polarizable and rigid molecule, and finally (d) a nonpolarizable and rigid molecule. The goal is to determine how significant the different molecular properties are. The results indicate that all factors-nonadditivity, polarizability, and intramolecular flexibility-are important. Still, approximations can be made in order to diminish the computational cost of the simulations with a small decrease in the accuracy of the predictions, provided that those approximations are counterbalanced by the proper inclusion of an effective molecular property, that is, an average molecular geometry or an average dipole. Hence instead of building an effective force field by parametrizing it in order to reproduce the properties of a specific phase, a building approach is proposed that is based on adequately restricting the molecular flexibility and/or polarizability of a model potential fitted to unimolecular properties, pair interactions, and many-body nonadditive contributions. In this manner, the same parental model can be used to simulate the same substance under a wide range of thermodynamic conditions. An additional advantage of this approach is that, as the force field improves by the quality of the molecular calculations, all levels of modeling can be improved.

Saint-Martin, Humberto; Hernández-Cobos, Jorge; Ortega-Blake, Iván

2005-06-01

325

How the potentials in different gauges yield the same retarded electric and magnetic fields  

Microsoft Academic Search

This paper presents a simple and systematic method to show how the potentials\\u000ain the Lorentz, Coulomb, Kirchhoff, velocity and temporal gauges yield the same\\u000aretarded electric and magnetic fields. The method appropriately uses the\\u000adynamical equations for the scalar and vector potentials to obtain two wave\\u000aequations, whose retarded solutions lead to the electric and magnetic fields.\\u000aThe advantage

Jose? A. Heras; Mexico D. F. Mexico

2007-01-01

326

Quaternary megafans, large rivers and other avulsive systems: a potential "who is who" in the geological record  

NASA Astrophysics Data System (ADS)

A fascinating discussion has been recently calling the attention of sedimentologists and geomorphologists regarding to the dominant fluvial styles preserved in the geological record. While some authors postulate that distributary (or distributive) patterns are the most important systems likely to dominate the alluvial rock record (Weissmann et al.2010, among others) others suggest that a variety of fluvial styles are remarkably preserved in the geological record, rejecting the importance of the distributary systems (such as megafans and other like fans coastal systems) (Fielding et al, 2012 among others). However, the Quaternary record of the largest depositional tracks on Earth has been not assessed in a comparative and detailed way. Here I present results from some of the most important Quaternary areas of sedimentation of the world such as the alluvial belts of the largest rivers, the largest megafans and other impressive fluvial dominated wetlands in active tectonic basins. My study is based on field work I carried out in many of the analyzed areas, a literature review and remote sensing products. Specific examples are discussed from several rivers of the Amazon basin, the Parana River, the Mississippi River, among others. Large depositional tracks in forelands, platforms and intracratonic basins such as the Chaco, the Orinoco Llanos, the Bananal and Pantanal basin, the Ucamara depression, and the Indo-Gangetic plain, which contain a variety of complex avulsive systems and megafans, are discussed. A main conclusion is that megafans and similar distributary systems, avulsive systems with a variety of channel patterns and linear fluvial belts of major rivers, have the potential for preservation in the geological record. The scarcity of purely braided systems in large rivers is noticeable and they are mainly constrained to small-medium size channels, short length piedmont courses or related to relatively small alluvial fans. Meandering and anabranching systems are dominant in large rivers while anabranching systems are characteristic of megarivers. Despite the findings above, a remarkable challenge remains to identify characteristic facies assemblages for reconstructing large rivers, as they are not clearly identified in the geological record. The scale-size limitation of the architectural characteristics of fluvial landforms and the floodplain complexity of large systems are some of the challenges that need additional research when looking for analogs in the sedimentary record. References: Fielding, Christopher R., Ashworth, Philip J., Best, James L., Prokocki, EricW., Smith, Gregory H. Sambrook, (2012). Tributary, distributary and other fluvial patterns: What really represents the norm in the continental rock record?, Sedimentary Geology doi: 10.1016/j.sedgeo.2012.03.004 Weissmann, G.S., Hartley, A.J., Nichols, G.J., Scuderi, L.A., Olson, M., Buehler, H., Banteah, R., 2010. Fluvial form in modern continental sedimentary basins: distributive fluvial systems. Geology 38, 39-42

Latrubesse, E. M.

2012-12-01

327

Comparative profiling of the transcriptional response to iron restriction in six serotypes of Actinobacillus pleuropneumoniae with different virulence potential  

Microsoft Academic Search

BACKGROUND: Comparative analysis of gene expression among serotypes within a species can provide valuable information on important differences between related genomes. For the pig lung pathogen Actinobacillus pleuropneumoniae, 15 serotypes with a considerable variation in virulence potential and immunogenicity have been identified. This serotypic diversity can only partly be explained by amount of capsule and differences in the RTX toxin

Kirstine Klitgaard; Carsten Friis; Øystein Angen; Mette Boye

2010-01-01

328

QUASI-STATIONARY HETEROGENEOUS BURNING OF SPERICAL PARTICLE IN GASEOUS MEDIUM AT LARGE TEMPERATURE DIFFERENCES AND LARGE CONCENTRATIONS OF CHEMICALLY ACTIVE COMPONENT  

Microsoft Academic Search

The burning of carbon particles in the field of the laser radiation in the open air or in combustion chambers with the large oxygen concentrations can occur at the large temperature over-falls near particles (4). In this case it is necessary to take into account a dependence of gaseous medium diffusion and heat conduction coefficients of the temperature and the

E. R. Shchukin; L. A. Uvarova

2006-01-01

329

Estimating the Potential Impacts of Large Mesopredators on Benthic Resources: Integrative Assessment of Spotted Eagle Ray Foraging Ecology in Bermuda  

PubMed Central

Declines of large sharks and subsequent release of elasmobranch mesopredators (smaller sharks and rays) may pose problems for marine fisheries management as some mesopredators consume exploitable shellfish species. The spotted eagle ray (Aetobatus narinari) is the most abundant inshore elasmobranch in subtropical Bermuda, but its predatory role remains unexamined despite suspected abundance increases and its hypothesized specialization for mollusks. We utilized a combination of acoustic telemetry, benthic invertebrate sampling, gut content analysis and manipulative experiments to assess the impact of spotted eagle rays on Bermudian shellfish resources. Residency and distribution of adult spotted eagle rays was monitored over two consecutive summers in Harrington Sound (HS), an enclosed inshore lagoon that has historically supported multiple recreational and commercial shellfish species. Telemetered rays exhibited variable fidelity (depending on sex) to HS, though generally selected regions that supported relatively high densities of potential mollusk prey. Gut content analysis from rays collected in HS revealed a diet of mainly bivalves and a few gastropods, with calico clam (Macrocallista maculata) representing the most important prey item. Manipulative field and mesocosm experiments with calico clams suggested that rays selected prey patches based on density, though there was no evidence of rays depleting clam patches to extirpation. Overall, spotted eagle rays had modest impacts on local shellfish populations at current population levels, suggesting a reduced role in transmitting cascading effects from apex predator loss. However, due to the strong degree of coupling between rays and multiple protected mollusks in HS, ecosystem-based management that accounts for ray predation should be adopted.

Ajemian, Matthew J.; Powers, Sean P.; Murdoch, Thaddeus J. T.

2012-01-01

330

Large magnetic storms as viewed by TWINS: A study of the differences in the medium energy ENA composition  

NASA Astrophysics Data System (ADS)

large geomagnetic storms (Dst ?-100 nT), oxygen can become a significant component of the energetic particles of the inner magnetosphere. Until recently, there were no available global observations of the medium energy (<50 keV) oxygen populations. Using observations from the Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) Energetic Neutral Atom (ENA) imagers we present a study of nine large storms of solar cycle 24 as a function of storm phase. For these storms we observe that the H and O ENA fluxes and their temperatures increase in tandem during the storm's initial phase. However, there is no increase in the O+/H+ ratio in the inner magnetosphere until the storm main phase. Also seen during the main phase is an energy dispersion with higher-energy (32 keV) H ENAs seen before the arrival of O ENAs of the same energy. The O ENAs take longer to return to prestorm levels during the recovery phases. This longer recovery time is likely because of the large difference between the storm time and prestorm O populations compared to H (i.e., there is always some prestorm H in the inner magnetosphere, but effectively no O prestorm). These results imply that medium-energy O ENAs evolve over long time scales (hours to days) as opposed to the shorter substorm time scales of the higher-energy (>52 keV) O ENAs.

Valek, P. W.; Goldstein, J.; McComas, D. J.; Fok, M.-C.; Mitchell, D. G.

2014-04-01

331

Differences in passenger car and large truck involved crash frequencies at urban signalized intersections: an exploratory analysis.  

PubMed

The influence of intersection features on safety has been examined extensively because intersections experience a relatively large proportion of motor vehicle conflicts and crashes. Although there are distinct differences between passenger cars and large trucks-size, operating characteristics, dimensions, and weight-modeling crash counts across vehicle types is rarely addressed. This paper develops and presents a multivariate regression model of crash frequencies by collision vehicle type using crash data for urban signalized intersections in Tennessee. In addition, the performance of univariate Poisson-lognormal (UVPLN), multivariate Poisson (MVP), and multivariate Poisson-lognormal (MVPLN) regression models in establishing the relationship between crashes, traffic factors, and geometric design of roadway intersections is investigated. Bayesian methods are used to estimate the unknown parameters of these models. The evaluation results suggest that the MVPLN model possesses most of the desirable statistical properties in developing the relationships. Compared to the UVPLN and MVP models, the MVPLN model better identifies significant factors and predicts crash frequencies. The findings suggest that traffic volume, truck percentage, lighting condition, and intersection angle significantly affect intersection safety. Important differences in car, car-truck, and truck crash frequencies with respect to various risk factors were found to exist between models. The paper provides some new or more comprehensive observations that have not been covered in previous studies. PMID:24140813

Dong, Chunjiao; Clarke, David B; Richards, Stephen H; Huang, Baoshan

2014-01-01

332

Large interclone differences in melezitose secretion in the facultatively ant-tended black bean aphid Aphis fabae.  

PubMed

Many aphids are known to engage in a trophic mutualism with ants, whereby the aphids secrete sugary-rich honeydew which is collected by the ants for food, and the ants, in exchange, protect the aphids against natural enemies. Previous results, however, suggest that the production of some of the honeydew sugars, such as the ant-attractant trisaccharide melezitose, may induce an indirect cost to the aphids. This led us to believe that large differences in the nature of the secreted honeydew might exist, due to some clones capitalizing more or less on their mutualistic interaction with ants, or due to some "cheater" clones foregoing the production of particular sugars, instead taking advantage of the ant-attracting effect of other non sugar-deficient clones, co-occurring on the same plant. Here we present data on clonal variation in the composition of honeydew of the black bean aphid Aphis fabae which confirm this prediction. In particular, our results show that there was large interclone variation in the amount of glucose, melezitose and total sugar produced. The variation in the production of melezitose, however, showed particularly large differences, with 54% (7 out of 13) of the clones screened being virtually deficient for the production of this sugar, irrespective of whether the aphid colonies were ant-tended or not. The consequences of this finding in the context of the evolution and maintenance of the ant-aphid mutualism, as well as the adaptive benefits of oligosaccharide synthesis in aphids and other insects are discussed. PMID:21896277

Vantaux, A; Van den Ende, W; Billen, J; Wenseleers, T

2011-12-01

333

Potential on Using Cultural Syndromes for Explaining Differences in Attitudes in Northern and Southern EU Countries  

Microsoft Academic Search

Nowadays, it is more realistic to view the development of a new technology as a result of a complex social system of interactions and decisions. Understanding the public's range of views on biotechnology is important for decision makers, in order to be able to anticipate potential acceptance problems or, one step further, to take consumer or public desires and concerns

Asterios Tsioumanis; Konstadinos Mattas; G. Papastefanou; A. Springer

2004-01-01

334

Osteogenic Potential of Autogenous Bone Grafts Harvested with Four Different Surgical Techniques  

Microsoft Academic Search

The osteogenic potential of autogenous bone grafts is superior to that of allografts and xenografts because of their ability to release osteoinductive growth factors and provide a natural osteoconductive surface for cell attachment and growth. In this in vitro study, autogenous bone particles were harvested by four commonly used techniques and compared for their ability to promote an osteogenic response.

R. J. Miron; E. Hedbom; N. Saulacic; Y. Zhang; A. Sculean; D. D. Bosshardt; D. Buser

2011-01-01

335

Polyamines and related enzymes in rice seeds differing in germination potential  

Microsoft Academic Search

In ungerminated rice seeds, (Japonica rice variety, CV Tapei 309), the content of free amines (putrescine, spermidine, spermine, tyramine) was higher in seed lots having a low germination frequency compared to those with high germination potential. Conversely, amine conjugates (di-feruloylputrescine, di-feruloylspermidine, diferuloyldiaminopropane and feruloyltyramine) decreased with loss of viability. Thus, these compounds appeared to constitute biochemical markers of seed viability.

L. Bonneau; M. Carré; J. Martin-Tanguy

1994-01-01

336

Na+ imaging reveals little difference in action potential–evoked Na+ influx between axon and soma  

Microsoft Academic Search

In cortical pyramidal neurons, the axon initial segment (AIS) is pivotal in synaptic integration. It has been asserted that this is because there is a high density of Na+ channels in the AIS. However, we found that action potential–associated Na+ flux, as measured by high-speed fluorescence Na+ imaging, was about threefold larger in the rat AIS than in the soma.

Nechama Lasser-Ross; Michael J Gutnick; William N Ross; Ilya A Fleidervish

2010-01-01

337

The potential and force law between different-size bubbles in soap bubble rafts  

Microsoft Academic Search

Since the Bragg bubble model continues to be a powerful tool for modelling interatomic binding and inelastic processes in close-packed metals with particularly attractive applications to the mechanism of plastic flow in metallic glasses, the inter-bubble potential previously developed by Nicolson and Lomer has been generalized to cover interactions between bubbles of unequal size. Fitting the binding energy between pairs

L. T. Shi; A. S. Argon

1982-01-01

338

Antioxidant potential of peels and fleshes of peaches from different cultivars.  

PubMed

Increasing recent interest in nutraceuticals and functional foods has led researchers to investigate the antioxidant potential of several fruits. This article evaluates the antioxidant potential and reactivity based on luminol-enhanced chemiluminescence capacity of peach extracts (peels and fleshes) and the contribution of a major compound present in these extracts to antioxidant potential and reactivity. The results obtained showed that the extracts of peels and fleshes of Maciel, Leonense, and Eldorado peach cultivars present free radical scavenging activity in all concentrations tested, with a concentration-dependent action. The immediate inhibition of chemiluminescence and the duration of this inhibition were significantly higher with the extracts than with the major compound (chlorogenic acid) alone, and it can be due to a synergistic or additive effect of other antioxidants present in the extracts. The 50% inhibitory concentration (IC(50)) values for peach extract and chlorogenic acid were 1.19 microg/mL and 8.43 microg/mL, respectively, when total radical-trapping antioxidant potential was evaluated, whereas IC(50) values of 0.41 microg/mL and 1.89 microg/mL was found when total antioxidant reactivity was evaluated in peach extract and chlorogenic acid, respectively. Chlorogenic acid presented a good contribution to antioxidant reactivity and potential, but the fruit extracts provide better antioxidant action. Peach could be of great interest as an important antioxidant source including chlorogenic acid, and it may provide health-promoting advantages to consumers by intake of this fruit or by utilization of its peels as antioxidant sources in industry. PMID:19857078

Rossato, Simone B; Haas, Clarissa; Raseira, Maria do Carmo B; Moreira, José Cláudio F; Zuanazzi, José Angelo S

2009-10-01

339

Numerical study on the potential impact of different bottom boundary conditions on the water balance of lysimeters  

NASA Astrophysics Data System (ADS)

The SOILCan lysimeter network is a large scale climate feedback experiment and is embedded in the four long term observatories of TERENO (TERestrial ENvironmental Observatories). The focus of the SOILCan-project is to observe the impact of climate change on water and matter budgets in different grass- and arable-land lysimeters. The monitoring infrastructure was established across a rainfall and temperature transect along which lysimeters were transported from wetter to drier conditions. The lysimeters in SOILCan have a controlled bottom boundary condition using a rack of suction candles that enables upward and downward flow of water. This pressure head at the bottom is controlled by measured soil water potentials in undisturbed soil in the close vicinity of the bottom of the lysimeter. For transported lysimeters this controlling approach no longer works as the surrounding soil profile and both its upper climatic boundary conditions and lower boundary conditions related to its hydrogeological setting differ from the place where the lysimeter was taken from. In order to evaluate these artefacts and to derive a suited approach to control the lower boundary of transported lysimeters, water balance simulations were run. We analyzed three different approaches to impose bottom boundary conditions for transported lysimeters. A 'zeroth-order' approach is to define the bottom boundary at the bottom of the lysimeter and use the pressure heads measured at the location from which the soil lysimeter was taken. However, this approach is prone to artefacts since these bottom boundary conditions are determined by the climate at the site where the lysimeter was taken from. A 'first-order' approach is to define a bottom boundary condition at a certain hydrogeological boundary that can be defined deeper in the soil profile such as a seepage face or a groundwater table. However, for shallow groundwater tables, this approach may also lead to artefacts since the depth of the groundwater table may change with changing climate. In a 'second-order' approach, the effect of changing climate conditions on these bottom boundaries is evaluated. Therefore, other hydrogeological properties that determine lateral groundwater flow such as the depth of an impermeably layer and the distance between surface water structures that drain groundwater have to be considered in the approach as well. We will present a comparison of these approaches using water balance results derived by numerical simulation with the software HYDRUS 1-D.

Groh, Jannis; Vanderborght, Jan; Pütz, Thomas; Vereecken, Harry

2014-05-01

340

A large population of king crabs in Palmer Deep on the west Antarctic Peninsula shelf and potential invasive impacts  

PubMed Central

Lithodid crabs (and other skeleton-crushing predators) may have been excluded from cold Antarctic continental shelf waters for more than 14 Myr. The west Antarctic Peninsula shelf is warming rapidly and has been hypothesized to be soon invaded by lithodids. A remotely operated vehicle survey in Palmer Deep, a basin 120 km onto the Antarctic shelf, revealed a large, reproductive population of lithodids, providing the first evidence that king crabs have crossed the Antarctic shelf. DNA sequencing and morphology indicate the lithodid is Neolithodes yaldwyni Ahyong & Dawson, previously reported only from Ross Sea waters. We estimate a N. yaldwyni population density of 10 600 km?2 and a population size of 1.55 × 106 in Palmer Deep, a density similar to lithodid populations of commercial interest around Alaska and South Georgia. The lithodid occurred at depths of more than 850 m and temperatures of more than 1.4°C in Palmer Deep, and was not found in extensive surveys of the colder shelf at depths of 430–725 m. Where N. yaldwyni occurred, crab traces were abundant, megafaunal diversity reduced and echinoderms absent, suggesting that the crabs have major ecological impacts. Antarctic Peninsula shelf waters are warming at approximately 0.01°C yr?1; if N. yaldwyni is currently limited by cold temperatures, it could spread up onto the shelf (400–600 m depths) within 1–2 decades. The Palmer Deep N. yaldwyni population provides an important model for the potential invasive impacts of crushing predators on vulnerable Antarctic shelf ecosystems.

Smith, Craig R.; Grange, Laura J.; Honig, David L.; Naudts, Lieven; Huber, Bruce; Guidi, Lionel; Domack, Eugene

2012-01-01

341

A large population of king crabs in Palmer Deep on the west Antarctic Peninsula shelf and potential invasive impacts.  

PubMed

Lithodid crabs (and other skeleton-crushing predators) may have been excluded from cold Antarctic continental shelf waters for more than 14 Myr. The west Antarctic Peninsula shelf is warming rapidly and has been hypothesized to be soon invaded by lithodids. A remotely operated vehicle survey in Palmer Deep, a basin 120 km onto the Antarctic shelf, revealed a large, reproductive population of lithodids, providing the first evidence that king crabs have crossed the Antarctic shelf. DNA sequencing and morphology indicate the lithodid is Neolithodes yaldwyni Ahyong & Dawson, previously reported only from Ross Sea waters. We estimate a N. yaldwyni population density of 10 600 km(-2) and a population size of 1.55 × 10(6) in Palmer Deep, a density similar to lithodid populations of commercial interest around Alaska and South Georgia. The lithodid occurred at depths of more than 850 m and temperatures of more than 1.4°C in Palmer Deep, and was not found in extensive surveys of the colder shelf at depths of 430-725 m. Where N. yaldwyni occurred, crab traces were abundant, megafaunal diversity reduced and echinoderms absent, suggesting that the crabs have major ecological impacts. Antarctic Peninsula shelf waters are warming at approximately 0.01°C yr(-1); if N. yaldwyni is currently limited by cold temperatures, it could spread up onto the shelf (400-600 m depths) within 1-2 decades. The Palmer Deep N. yaldwyni population provides an important model for the potential invasive impacts of crushing predators on vulnerable Antarctic shelf ecosystems. PMID:21900324

Smith, Craig R; Grange, Laura J; Honig, David L; Naudts, Lieven; Huber, Bruce; Guidi, Lionel; Domack, Eugene

2012-03-01

342

A large survey of Croatian wild mammals for Giardia duodenalis reveals a low prevalence and limited zoonotic potential.  

PubMed

Wild mammals are considered an important source of potentially zoonotic Giardia duodenalis parasites, yet surprisingly little information is available on the actual prevalence and the genetic identity of the species they harbor. A large survey was conducted in Croatia by collecting 832 fecal samples from red deer (Cervus elaphus, n = 374), roe deer (Capreolus capreolus, n = 21), wild boars (Sus scrofa, n = 144), foxes (Vulpes vulpes, n = 66), bears (Ursus arctos, n = 19), wolves (Canis lupus, n = 127), jackals (Canis aureus, n = 8), and hares (Lepus europeus, n = 73). Fecal samples were tested for the presence of Giardia cysts using fluorescent microscopy. The observed prevalence ranged from low (1% in red deer, 1.7% in wild boars, and 4.5% in foxes) to moderate (10% in wolves and 12.5% in jackals) to high (24% in roe deer). No cysts were observed in bears and hares. Polymerase chain reaction was performed on microscopically positive samples to amplify fragments of the small subunit ribosomal gene, the ribosomal 5.8S gene and the two flanking internal transcribed sequences, and the triose phosphate isomerase gene. Sequence analysis showed a predominance of G. duodenalis assemblage A in both ruminants (genotypes A1 and A3) and carnivores (genotype A1). G. duodenalis assemblages B, C, and D, as well as Giardia microti, were also detected in this study. This is the first molecular description of the parasite from the red deer, the wolf, and the jackal. The data point to a minor role of wild mammals as reservoirs of zoonotic assemblages of G. duodenalis, albeit cycling between sylvatic and domestic animals is possible. PMID:21142957

Beck, Relja; Sprong, Hein; Lucinger, Snjezana; Pozio, Edoardo; Cacciò, Simone M

2011-08-01

343

Differences in Patterns of Adaptation in Conjugal Bereavement: Their Sources and Potential Significance.  

ERIC Educational Resources Information Center

Identified several different patterns of adaptation over first 18 months of bereavement represented by levels of subjective stress and depression in 131 widowed men and women. Anticipatory grief, concurrent stressors, social support, and spiritual support correlated with single significant function which discriminated between different courses of…

Levy, Leon H.; And Others

1994-01-01

344

Relative stability of different DNA guanine quadruplex stem topologies derived using large-scale quantum-chemical computations  

PubMed Central

We provide theoretical predictions of the intrinsic stability of different arrangements of guanine quadruplex (G-DNA) stems. Most computational studies of nucleic acids have applied Molecular Mechanics (MM) approaches using simple pairwise-additive force fields. The principle limitation of such calculations is the highly approximate nature of the force fields. In this study we for the first time apply accurate QM computations (DFT-D3 with large atomic orbital basis sets) to essentially complete DNA building blocks, namely, seven different folds of the cation-stabilized 2-quartet G-DNA stem, each having more than 250 atoms. The solvent effects are approximated by COSMO continuum solvent. We reveal sizeable differences between MM and QM descriptions of relative energies of different G-DNA stems, which apparently reflect approximations of the DNA force field. Using the QM energy data, we propose correction to earlier free energy estimates of relative stabilities of different parallel, hybrid and antiparallel G-stem folds based on classical simulations. The new energy ranking visibly improves the agreement between theory and experiment. We predict the 5?-anti-anti-3? GpG dinucleotide step to be the most stable one, closely followed by the 5?-syn-anti-3? step. The results are in good agreement with known experimental structures of 2, 3 and 4-quartet G-DNA stems. Besides providing specific results for G-DNA, our study highlights basic limitations of force field modeling of nucleic acids. Although QM computations have their own limitations, mainly the lack of conformational sampling and the approximate description of the solvent, they can substantially improve quality of calculations currently relying exclusively on force fields.

Sponer, Jiri; Mladek, Arnost; Spackova, Nad'a; Cang, Xiaohui; Cheatham, Thomas E.; Grimme, Stefan

2013-01-01

345

Multiple CP non-conserving mechanisms of ( ??)0 ? -decay and nuclei with largely different nuclear matrix elements  

NASA Astrophysics Data System (ADS)

We investigate the possibility to discriminate between different pairs of CP non-conserving mechanisms inducing the neutrinoless double beta ( ??)0 ? -decay by using data on ( ??)0 ? -decay half-lives of nuclei with largely different nuclear matrix elements (NMEs). The mechanisms studied are: light Majorana neutrino exchange, heavy left-handed (LH) and heavy right-handed (RH) Majorana neutrino exchanges, lepton charge non-conserving couplings in SUSY theories with R-parity breaking giving rise to the "dominant gluino exchange" and the "squark-neutrino" mechanisms. The nuclei considered are 76Ge, 82Se, 100Mo, 130Te and 136Xe. Four sets of nuclear matrix elements (NMEs) of the decays of these five nuclei, derived within the Self-consistent Renormalized Quasiparticle Random Phase Approximation (SRQRPA), were employed in our analysis. While for each of the five single mechanisms discussed, the NMEs for 76Ge, 82Se, 100Mo and 130Te differ relatively little, the relative difference between the NMEs of any two nuclei not exceeding 10%, the NMEs for 136 Xe differ significantly from those of 76Ge, 82 Se, 100Mo and 130Te, being by a factor ~ (1.3 - 2.5) smaller. This allows, in principle, to draw conclusions about the pair of non-interfering (interfering) mechanisms possibly inducing the ( ??)0 ? -decay from data on the half-lives of 136 Xe and of at least one (two) more isotope(s) which can be, e.g., any of the four, 76 Ge, 82 Se, 100 Mo and 130 Te. Depending on the sets of mechanisms considered, the conclusion can be independent of, or can depend on, the NMEs used in the analysis. The implications of the EXO lower bound on the half-life of 136 Xe for the problem studied are also exploited.

Meroni, A.; Petcov, S. T.; Šimkovic, F.

2013-02-01

346

Predicting Reading Growth with Event-Related Potentials: Thinking Differently about Indexing "Responsiveness"  

PubMed Central

The purpose of this study was to determine if event-related potential (ERP) data collected during three reading-related tasks (Letter Sound Matching, Nonword Rhyming, and Nonword Reading) could be used to predict short-term reading growth on a curriculum-based measure of word identification fluency over 19 weeks in a sample of 29 first-grade children. Results indicate that ERP responses to the Letter Sound Matching task were predictive of reading change and remained so after controlling for two previously validated behavioral predictors of reading, Rapid Letter Naming and Segmenting. ERP data for the other tasks were not correlated with reading change. The potential for cognitive neuroscience to enhance current methods of indexing responsiveness in a response-to-intervention (RTI) model is discussed.

Lemons, Christopher J.; Key, Alexandra P.F.; Fuchs, Douglas; Yoder, Paul J.; Fuchs, Lynn S.; Compton, Donald L.; Williams, Susan M.; Bouton, Bobette

2009-01-01

347

A comparative study of sub-barrier fusion using different proximity based potentials  

NASA Astrophysics Data System (ADS)

We study fusion probabilities at sub-barrier energies using potentials due to AW 95, Bass 80, Denisov DP and Proximity 2010. The fusion reactions for 16O+70,72Ge, 27Al+70,72Ge, 40Ca+48,50Ti, 40Ca+58,62Ni, 32S+90,96Zr and 40Ca+90,96Zr are studied at sub-barrier energies. We find that our theoretical calculations using all these proximity based potentials nicely explain the sub-barrier fusion cross-sections for the reaction series of O+Ge. However, small deviations are observed in sub-barrier region in case of other reactions and are attributed to deformed shape of the nuclei, surface vibrations and multi-neutron transfer channels.

Kumari, Raj

2013-04-01

348

Redox potentials in relation to water levels in different mire types in the Netherlands and Poland  

Microsoft Academic Search

In mires in the Netherlands and Poland redox potentials were measured in situ in 8-fold at 15 cm below the peat surface in 10 m2 plots. Measurements were repeated 2–4 times in time at ca. 240 locations. Simultaneously, water levels were recorded in piezometers and water samples were analysed for pHwater. pHKCl was determined in peat samples. The relationship between

Hans de Mars; Martin J. Wassen

1999-01-01

349

Leaf osmotic potential of Eucalyptus hybrids responds differently to freezing and drought, with little clonal variation.  

PubMed

Concentrations of solutes, and thus leaf osmotic potential (Psi pi), often increase when plants are subject to drought or sub-zero (frost) temperatures. We measured Psi pi and concentrations of individual solutes in leaves of 3-year-old Eucalyptus camaldulensis Dehn., E. globulus Labill., E. grandis W. Hill ex Maid. and 29 hybrid clones on a site subjected to both summer drought and winter frost. We sought to characterize seasonal and genetic variations in Psi pi and to determine whether Psi pi or leaf turgor is related to bole volume increment. Leaf osmotic potential at full turgor (Psi pi(100)) was 0.7 MPa more negative in winter than in late summer, and this trend was uniform across genotypes. Soluble carbohydrates were confirmed as key contributors to Psi pi, accounting for 40-44% of total osmolality. The seasonal trend in Psi pi(100) was facilitated by changes in leaf morphology, such as reduced turgid mass:dry mass ratio and increased apoplastic water fraction in winter. Cell wall elasticity increased significantly from winter to summer. Our results suggest that elastic adjustment may be more important than osmotic adjustment in leaves exposed to drought. Although Psi pi(100) was a reasonable predictor of in situ osmotic potential and turgor, we found no relationship between any physiological trait and bole volume increment. Clone-within-family variation in Psi pi(100) was small in both summer and winter and was unrelated to bole volume increment. We conclude that, for the study species, tree improvement under water-limited conditions should concentrate on direct selection for growth rather than on indirect selection based on osmotic potential. PMID:18519261

Callister, Andrew N; Arndt, Stefan K; Ades, Peter K; Merchant, Andrew; Rowell, Douglas; Adams, Mark A

2008-08-01

350

Individual differences in personality profiles among potential living kidney transplant donors  

PubMed Central

Background: Although the psychological assessment of potential living kidney donors (PLKD) is part of the recommendations for action for any transplant coordination, there are not many studies that provide data about the importance of selecting donors for improving transplant outcomes. This work aims to raise awareness of potential kidney donors by designing methods for early detection of potential problems after the transplant, as well as by selecting the most suitable donors. Methods: This is a study of 25 PLKD drawn from the General University Hospital of Alicante. Participants completed the Millon Clinical Multiaxial Inventory (MCMI-III) for the study of personality characteristics. Results: Women scored higher than men in the compulsive personality scale, and individuals with a genetic link with the recipient scored higher on depressive and dependent scales than did those with other relationships (emotional or altruistic). Conclusions: Women showed a pattern of significantly more compulsive personality traits (cautious, controlled, perfectionist) within a non-pathological style. Among the PLKD, there were significantly more women, which is contrary to what typically happens with donations from cadavers. Genetically related subjects scored higher on depression than did those that were emotionally related. The personality assessment of candidates for PLKD can help with developing a post-transplant follow-up regimen for an improved quality of life.

Rodriguez-Marin, Jesus; Martinez-Zaragoza, Fermin; de Santiago-Guervos, Carlos

2013-01-01

351

The effective group potential, a new method for the study of spectrum in large molecules: Tests and perspectives  

Microsoft Academic Search

The new method, called effective group potential, which generalizes the concept of effective core potential by including in a potential the effects of many atoms ligand, is used to calculate transition energies. Three molecules containing a metal atom (Cu, Cr, Ni) surrounded by NH3 ligands have been studied. It is shown that by replacing the NH3 group by an effective

Jean-Louis Heully; Romuald Poteau; Sandra Berasaluce; Fabienne Alary

2002-01-01

352

Similarities and differences between a large meandering river and an anabranching river: the Ucayali and Amazon River cases  

NASA Astrophysics Data System (ADS)

The Ucayali is one of the largest freely meandering rivers in the world and its planform migration produces complex meander shapes dominated by not only fluvial erosion but mainly geotechnical processes since changes on water stage are appreciable compared to medium- and small-meander rivers. The Amazon is one of the largest anabranching rivers in the world and it is formed by the confluence of the anabranching Marañon River together with the meandering Ucayali River. The seasonal increase and decrease in water and sediment discharges from the Amazonian lowland rivers produce changes in the river’s planform configuration, river flooding, and streambank erosion affecting nearby towns and navigation and shoaling issues. Even though, extensive work has been dedicated to understand both river systems, there is still no absolute understanding of their physically-based formation processes and dynamics, especially at large scales as these lowland Amazonian rivers. The Ucayali Meandering River migrates at greater rates than the Amazon Anabranching River mainly due to their single channel condition; however localized secondary channels of the latter could behave as meandering channels dominating and modifying the planform dynamics of the entire anabranching system. Insights on how a large meandering river (Ucayali) is similar and at the same time different from an anabranching river (Amazon) will be described herein. A team composed of the Earth Processes & Environmental Flows Group (EPEF) at the University of Pittsburgh and the Directorate of Hydrology and Navigation (DHN) from the Peruvian Navy is working towards gathering information and field measurements concerning the dynamics of the Amazonian rivers. Therefore, based on three-dimensional velocity and bed morphodynamic measurements (performed in both river systems using acoustic profilers and echo sounders respectively) combined with mathematical hydrodynamic models, some insights on the flow structure, bed morphology and planform dynamics of large meandering and anabranching systems are presented.

Abad, J. D.; Paredes, J. R.; Montoro, H.

2010-12-01

353

Racial Differences in Advanced Colorectal Cancer Outcomes and Pharmacogenetics: A Subgroup Analysis of a Large Randomized Clinical Trial  

PubMed Central

Purpose Racial disparities in colorectal cancer (CRC) survival are documented, but there are few data on comparative response to chemotherapy. A subgroup analysis of a multisite National Cancer Institute–sponsored trial (N9741) was performed comparing outcomes of black and white patients with metastatic CRC receiving uniform treatment. Patients and Methods Adverse events (AEs), response rate (RR), time to progression (TTP), overall survival (OS), and dose-intensity were examined as a function of self-reported race in 1,412 patients treated with irinotecan/fluorouracil, fluorouracil/oxaliplatin, or irinotecan/oxaliplatin. Pharmacogenetic analysis was performed on 486 patients with blood available for germline DNA analysis. Results OS was 1.5 months shorter and TTP was 0.6 months shorter in black than white patients (OS: hazard ratio [HR] = 1.13; 95% CI, 0.90 to 1.42; TTP: HR = 0.91, 95% CI, 0.73 to 1.13); neither difference was statistically significant. RR was significantly higher in whites (41%) than blacks (28%; P = .008). Grade 3 or greater AEs were also higher in whites (48%) than blacks (34%; P = .004). These relationships were maintained in multivariate models adjusting for arm, age, sex, and performance status. There was no difference in dose-intensity of delivered therapy. Significant racial differences in prevalence of pharmacogenetic variants were observed, although small sample size precluded investigating the relationship between treatment, race, and genotype. Conclusion OS and TTP are similar in black and white patients treated per protocol with standardized therapy for metastatic CRC. However, RR and AEs vary considerably by race. The marked racial differences in relevant pharmacogenetics, a potential explanation for differing RR and AEs, are worthy of future study.

Sanoff, Hanna K.; Sargent, Daniel J.; Green, Erin M.; McLeod, Howard L.; Goldberg, Richard M.

2009-01-01

354

Heat transfer and pressure changes due to a large temperature difference across an enclosed vertical air layer  

NASA Astrophysics Data System (ADS)

The TRACE-2D Code has been used to obtain non-Boussinesq results from transient, compressible and two-dimensional calculations using Sutherland law conductivity and viscosity property variations for air. These free convection results are limited to the laminar flow region. The aspect ratio A of the vertical air layer, with adiabatic top and bottom walls, is taken to be unity or greater, and the Rayleigh number Ra based on the layer width is as large as 10 to the 7th power when A = 1. The results are valid for large temperature differences between the hot and cold isothermal walls, epsilon = sub T(h) - sub T(c) or = 0.6, where the limitation is due to the Sutherland law accuracy. The various flow regimes are defined in terms of epsilon, A and Ra and correlations are developed for the Nusselt number and pressure in terms of these parameters. It is shown that, with proper non-dimensionalization, much of the vast body of literature concerning Nusselt number correlations and vertical temperature stratification for the Boussinesq case (which is asymptotically approached here for epsilon 1) can be used where epsilon is not small.

Chenoweth, D. R.; Paolucci, S.

1984-08-01

355

Cell Surface Properties of B16 Melanoma Variants with Differing Metastatic Potential1  

Microsoft Academic Search

Several cell surface properties of three B16 melanoma var iant lines, which exhibit differing lung-colonizing capacities, have been examined. Equal numbers of cells from the B16- F10Lr and B16-F1 lines, injected i.v. into syngeneic mice, produced significantly fewer lung nodules than did cells of the B16-F10 line. These wide differences in biological behavior could not, however, be ascribed to major

A. Raz; W. L. McLellan; I. R. Hart; C. D. Bucana; L. C. Hoyer; P. Dragsten; I. J. Fidler

356

Structural Rationalization of a Large Difference in RNA Affinity Despite a Small Difference in Chemistry between Two 2'-O-Modified Nucleic Acid Analogs  

SciTech Connect

Chemical modification of nucleic acids at the 2'-position of ribose has generated antisense oligonucleotides (AONs) with a range of desirable properties. Electron-withdrawing substituents such as 2'-O-[2-(methoxy)ethyl] (MOE) confer enhanced RNA affinity relative to that of DNA by conformationally preorganizing an AON for pairing with the RNA target and by improving backbone hydration. 2'-Substitution of the ribose has also been shown to increase nuclease resistance and cellular uptake via changes in lipophilicity. Interestingly, incorporation of either 2'-O-[2-(methylamino)-2-oxoethyl]- (NMA) or 2'-O-(N-methylcarbamate)-modified (NMC) residues into AONs has divergent effects on RNA affinity. Incorporation of 2'-O-NMA-T considerably improves RNA affinity while incorporation of 2'-O-NMC-T drastically reduces RNA affinity. Crystal structures at high resolution of A-form DNA duplexes containing either 2'-O-NMA-T or 2'-O-NMC-T shed light on the structural origins of the surprisingly large difference in stability given the relatively minor difference in chemistry between NMA and NMC. NMA substituents adopt an extended conformation and use either their carbonyl oxygen or amino nitrogen to trap water molecules between phosphate group and sugar. The conformational properties of NMA and the observed hydration patterns are reminiscent of those found in the structures of 2'-O-MOE-modified RNA. Conversely, the carbonyl oxygen of NMC and O2 of T are in close contact, providing evidence that an unfavorable electrostatic interaction and the absence of a stable water structure are the main reasons for the loss in thermodynamic stability as a result of incorporation of 2'-O-NMC-modified residues.

Pattanayek, R.; Sethaphong, L.; Pan, C.; Prhavc, M.; Prakash, T.P.; Manoharan, M.; Egli, M. (Tennessee); (Isis Pharmaceuticals Inc.); (Alnylam Pharmaceuticals,); (Vanderbilt)

2010-03-08

357

Evaluation of the Potential Environmental Impacts from Large-Scale Use and Production of Hydrogen in Energy and Transportation Applications  

SciTech Connect

The purpose of this project is to systematically identify and examine possible near and long-term ecological and environmental effects from the production of hydrogen from various energy sources based on the DOE hydrogen production strategy and the use of that hydrogen in transportation applications. This project uses state-of-the-art numerical modeling tools of the environment and energy system emissions in combination with relevant new and prior measurements and other analyses to assess the understanding of the potential ecological and environmental impacts from hydrogen market penetration. H2 technology options and market penetration scenarios will be evaluated using energy-technology-economics models as well as atmospheric trace gas projections based on the IPCC SRES scenarios including the decline in halocarbons due to the Montreal Protocol. Specifically we investigate the impact of hydrogen releases on the oxidative capacity of the atmosphere, the long-term stability of the ozone layer due to changes in hydrogen emissions, the impact of hydrogen emissions and resulting concentrations on climate, the impact on microbial ecosystems involved in hydrogen uptake, and criteria pollutants emitted from distributed and centralized hydrogen production pathways and their impacts on human health, air quality, ecosystems, and structures under different penetration scenarios

Wuebbles, D.J.; Dubey, M.K., Edmonds, J.; Layzell, D.; Olsen, S.; Rahn, T.; Rocket, A.; Wang, D.; Jia, W.

2010-06-01

358

Traumatic brain injury and hemorrhagic shock: evaluation of different resuscitation strategies in a large animal model of combined insults.  

PubMed

Traumatic brain injury (TBI) and hemorrhagic shock (HS) are the leading causes of trauma-related mortality and morbidity. Combination of TBI and HS (TBI + HS) is highly lethal, and the optimal resuscitation strategy for this combined insult remains unclear. A critical limitation is the lack of suitable large animal models to test different treatment strategies. We have developed a clinically relevant large animal model of TBI + HS, which was used to evaluate the impact of different treatments on brain lesion size and associated edema. Yorkshire swine (42-50 kg) were instrumented to measure hemodynamic parameters and intracranial pressure. A computer-controlled cortical impact device was used to create a TBI through a 20-mm craniotomy: 15-mm cylindrical tip impactor at 4 m/s velocity, 100-ms dwell time, and 12-mm penetration depth. Volume-controlled hemorrhage was started (40% blood volume) concurrent with the TBI. After 2 h of shock, animals were randomized to one of three resuscitation groups (n = 5/group): (a) normal saline (NS); (b) 6% hetastarch, Hextend (Hex); and (c) fresh frozen plasma (FFP). Volumes of Hex and FFP matched the shed blood, whereas NS was three times the volume. After 6 h of postresuscitation monitoring, brains were sectioned into 5-mm slices and stained with TTC (2,3,5-triphenyltetrazolium chloride) to quantify the lesion size and brain swelling. Combination of 40% blood loss with cortical impact and a period of shock (2 h) resulted in a highly reproducible brain injury. Total fluid requirements were lower in the Hex and FFP groups. Lesion size and brain swelling in the FFP group (2,160 ± 202.63 mm and 22% ± 1.0%, respectively) were significantly smaller than those in the NS group (3,285 ± 130.8 mm3 and 37% ± 1.6%, respectively) (P < 0.05). Hex treatment decreased the swelling (29% ± 1.6%) without reducing the lesion size. Early administration of FFP reduces the size of brain lesion and associated swelling in a large animal model of TBI + HS. In contrast, artificial colloid (Hex) decreases swelling without reducing the actual size of the brain lesion. PMID:22575994

Jin, Guang; DeMoya, Marc A; Duggan, Michael; Knightly, Thomas; Mejaddam, Ali Y; Hwabejire, John; Lu, Jennifer; Smith, William Michael; Kasotakis, Georgios; Velmahos, George C; Socrate, Simona; Alam, Hasan B

2012-07-01

359

The reactive oxidant potential of different types of aged atmospheric particles: An outdoor chamber study  

NASA Astrophysics Data System (ADS)

The reactive oxygen species (ROS) potential of aged diesel exhaust particulate matter (PM) and other aged aerosol systems in the presence and absence of an urban hydrocarbon environment was assessed. Experiments were performed in a 274 m 3 dual outdoor Teflon film chamber. Filter samples were taken to assess the oxidant generation associated with PM by an optimized dithiothreitol (DTT) method. Diesel exhaust PM had a higher ROS response when it was in the presence of an urban hydrocarbon mixture and was associated with significant O 3 production. For all the aged dilute diesel systems, ROS expression increased by a factor of 2-4 over fresh diesel particles. Other particle systems were also investigated. A low ROS was observed in most of the nighttime experiments, including the nighttime aerosols from SO 2 with O 3 and SO 2 aged by itself. However, when all the systems were compared, aged diesel exhaust tended to express very high ROS potentials, with secondary organic aerosols from an ?-pinene + toluene + an urban HC mixture giving the highest ROS response.

Rattanavaraha, Weruka; Rosen, Eli; Zhang, Haofei; Li, Qianfeng; Pantong, Karun; Kamens, Richard M.

2011-07-01

360

The percentage flow-mediated dilation index: a large-sample investigation of its appropriateness, potential for bias and causal nexus in vascular medicine.  

PubMed

The percentage flow-mediated dilation index (FMD%) scales the increase in arterial diameter (Ddiff) as a constant proportion of baseline artery diameter (Dbase). We have demonstrated, albeit with small samples, that the scaling properties of FMD% can lead to biased inferences on endothelial dysfunction. Therefore, we aimed to investigate the underlying rationale and potential bias of FMD% using a selection of new examples from the large (n = 3499) and diverse Multi-Ethnic Study of Atherosclerosis (MESA). In this dataset, we found that smaller values of Ddiff are associated with larger values of Dbase, which contradicts the scaling properties of FMD%. Consequently, FMD% 'over-scales' and naturally generates an even stronger negative correlation between itself and Dbase. Using a data simulation, we show that this FMD%-Dbase correlation can be a statistical artefact due to inappropriate scaling. The new examples we present from MESA indicate that FMD% biases the differences in flow-mediated response between men and women, Framingham risk score categories, and diseased and healthy people. We demonstrate how FMD%, as an exposure for predicting cardiovascular disease, is confounded by its dependency on Dbase, which itself could be clinically important. This critical review, incorporating an allometric analysis of a large dataset, suggests that the FMD% index has a less-than-clear rationale, can itself generate the Dbase-dependency problem, provides biased estimates of differences in the flow-mediated response, complicates the interpretation of the flow-mediated protocol and clouds the causal pathway to vascular disease. These interpretative problems can be resolved by applying accepted allometric principles to the flow-mediated response. PMID:24172228

Atkinson, Greg; Batterham, Alan M

2013-12-01

361

Regional differences in HIV prevalence among drug users in China: potential for future spread of HIV?  

PubMed Central

Background Drug use and in particular injecting drug use has been at the forefront of the explosive spread of HIV in general populations in many countries in Asia. There is concern that also in China increased HIV incidence in drug users might spark off a generalized epidemic in the wider population. Close monitoring of HIV incidence and risk factors in drug users is therefore important to be able to target interventions effectively. Second generation surveillance was launched to assess HIV prevalence and risk behaviours jointly with the purpose of describing trends and predicting future developments. To assess whether these goals were fulfilled among drug users in China we provide an analysis of risk factors for HIV infection and of regional differences in HIV prevalence. Methods We analysed data collected in 2005 in 21 drug user second generation surveillance sentinel sites from 14 provinces in China. We used random effects logistic regression to test for risk factors for HIV infection and regional differences. Results The overall HIV-1 antibody prevalence was 5.4% (279/5128); 4.9% among injecting drug users (IDU) not sharing needles and 3.7% among non-injecting drug users. We found substantial heterogeneity among the surveillance sites with prevalence rates ranging between 0% and 54%. HIV status was strongly affected by the regional prevalence of HIV. Risk behaviours were highly prevalent in regions where HIV prevalence is still low. The distribution of duration of drug use in different sites indicated different stages of the drug use epidemics. Conclusion ]Regional differences in HIV prevalence in China reflect different stages of the drug use and HIV epidemics rather than differences in risk behaviours. Therefore, outbreaks of HIV among drug users in regions where prevalence is still low can be expected in the future. However, methodological limitations of surveillance embedded into routine systems limit the usability of existing data. More standardized approaches to data collection in secondary generation HIV surveillance are necessary to better understand regional differences in risk behaviour and prevalence and to design targeted intervention for those regions at risk of experiencing outbreaks.

Kretzschmar, Mirjam; Zhang, Weidong; Mikolajczyk, Rafael T; Wang, Lan; Sun, Xinhua; Kraemer, Alexander; Lv, Fan

2008-01-01

362

Effect of Noise from DC-Driven Trains to Geoelectrical Potential Difference and its Reduction in Hakuba Area, Japan  

NASA Astrophysics Data System (ADS)

The variations of geoelectrical potential differences in Hakuba area, Nagano Prefecture, Japan have been investigated. The noises originated from the DC-driven trains were found to contaminate the natural geoelectrical potential data. The most intense influence of trains occurred when the train was running nearby measuring dipoles. The gradient of the potential was deflected towards the railways and/or the position of the train, exhibiting a certain correlation between the power supply data at substation and the geoelectrical potential data at measuring sites. Extracting the high correlation part (r > 0.7), “idealized” train noise can be computed by the least square method. The reduction of train noise by more than 60 % was achieved by subtracting the idealized noise from observed data.

Ishikawa, Hisashi; Hattori, Katsumi; Takahashi, Ichiro; Noda, Yoichi; Nagao, Toshiyasu; Isezaki, Nobuhiro

363

Large scale features associated with strong frontogenesis in equivalent potential temperature in the South American subtropics east of the Andes  

NASA Astrophysics Data System (ADS)

South American subtropics east of the Andes exhibit a region of intense climatological frontogenesis in equivalent potential temperature (EPT) in the December to March season, mostly produced by deformation of the wind field. The goal of this paper is to investigate the large scale features associated with intense and weak frontogenesis by deformation (FGD) in EPT in the region where it attains its climatological maximum. This can be approximately delimited by 32-42° S and 66-69° W, which is small enough as to contain only one synoptic perturbation at a time. The spatial average of the positive values of frontogenesis at 850 hPa over the whole region (DFG+) is used to represent the strength of the perturbation. ECMWF ERA-40 reanalysis data set is used to calculate DFG+ at six hour intervals for 21 seasons (1981-2002). Compositing analysis is carried out for strong (above the 0.75 quantile) and weak (below the 0.25 quantile) events. For strong events the geopotential field at 850 hPa exhibits the North Argentinean Low (NAL), a transient trough and the Low Pressure Tongue East of the Andes (LPT). Upon comparison with the composite field of FGD it can be observed that FGD exhibits a strong maximum over the Argentinean Col (AC) which separates the NAL and the trough. These features are absent in the weak frontogenesis composite, which exhibits a stronger South Pacific Subtropical High close to the continent. At 250 hPa the strong FGD composite exhibits a trough over the Andes with a wind speed maximum to its east. Both of these features are associated with the deepening of the NAL in the literature. These are not present in the weak FGD composites. Strong events show an intense quasi meridional corridor of water vapor transport from the Amazon to the subtropics that encounters westerly flow in the neighborhood of the AC. This is absent in weak events. A preliminary analysis of precipitation is carried out using the GPCP daily data set. An intense precipitation nucleus appears slightly northeast of the AC, with maximum intensity in the day that follows the strong events. Weak events exhibit a drying of the subtropics instead, between one and three days after the events. Higher precipitation over the oceanic South Atlantic Convergence Zone can be also observed. Analogous composites were constructed for the presence and absence of both the AC and the LPT, showing similar characteristics to the strong and weak FGD event composites respectively, but with lower intensities. This shows that by selecting strong FGD events, intense NAL and LPT events are also singled out.

Arraut, J. M.; Barbosa, H. M. J.

2009-10-01

364

Relationship between changes in intraluminal pressure and transmural potential difference in the human and canine jejunum in vivo  

Microsoft Academic Search

Recordings of transmural potential difference (PD) across the jejunum of conscious man in situ are characterised by spontaneous fluctuations of up to 10 mV. In 25 of 31 subjects (comprising seven normal controls and 24 patients under investigation for malabsorption, six of whom had coeliac disease) we observed a clear association between these fluctuations and changes in intraluminal pressure recorded

N W Read; R H Smallwood; R J Levin; C D Holdsworth; B H Brown

1977-01-01

365

Improving Students' Ability to Intuitively Infer Resistance from Magnitude of Current and Potential Difference Information: A Functional Learning Approach  

ERIC Educational Resources Information Center

The study examined the knowledge of the functional relations between potential difference, magnitude of current, and resistance among seventh graders, ninth graders, 11th graders (in technical schools), and college students. It also tested the efficiency of a learning device named "functional learning" derived from cognitive psychology on the…

Chasseigne, Gerard; Giraudeau, Caroline; Lafon, Peggy; Mullet, Etienne

2011-01-01

366

Individual Differences in Nonverbal Number Discrimination Correlate with Event-Related Potentials and Measures of Probabilistic Reasoning  

ERIC Educational Resources Information Center

The current study investigated the neural activity patterns associated with numerical sensitivity in adults. Event-related potentials (ERPs) were recorded while adults observed sequentially presented display arrays (S1 and S2) of non-symbolic numerical stimuli (dots) and made same/different judgments of these stimuli by pressing a button only when…

Paulsen, David J.; Woldorff, Marty G.; Brannon, Elizabeth M.

2010-01-01

367

On the generation of potential differences across the membranes of ellipsoidal cells in an alternating electrical field  

Microsoft Academic Search

Summary Particles with a nonconducting membrane, oriented in an alternating electrical field, will show the behaviour of electrical dipoles. Across the membranes there will be generated alternating electrical potential differences, which may be calculated for confocal ellipsoidal cells by solving Laplace's equation. We have evaluated a formula valid generally for single confocal ellipsoidal cells under physiological conditions, the cells being

J. Bernhardt; H. Pauly

1973-01-01

368

Redox potential of pheophytin a in photosystem II of two cyanobacteria having the different special pair chlorophylls  

PubMed Central

Water oxidation by photosystem (PS) II in oxygenic photosynthetic organisms is a major source of energy on the earth, leading to the production of a stable reductant. Mechanisms generating a high oxidation potential for water oxidation have been a major focus of photosynthesis research. This potential has not been estimated directly but has been measured by the redox potential of the primary electron acceptor, pheophytin (Phe) a. However, the reported values for Phe a are still controversial. Here, we measured the redox potential of Phe a under physiological conditions (pH 7.0; 25 °C) in two cyanobacteria with different special pair chlorophylls (Chls): Synechocystis sp. PCC 6803, whose special pair for PS II consists of Chl a, and Acaryochloris marina MBIC 11017, whose special pair for PS II consists of Chl d. We obtained redox potentials of ?536 ± 8 mV for Synechocystis sp. PCC 6803 and ?478 ± 24 mV for A. marina on PS II complexes in the presence of 1.0 M betaine. The difference in the redox potential of Phe a between the two species closely corresponded with the difference in the light energy absorbed by Chl a versus Chl d. We estimated the potentials of the special pair of PS II to be 1.20 V and 1.18 V for Synechocystis sp. PCC 6803 (P680) and A. marina (P713), respectively. This clearly indicates conservation in the properties of water-oxidation systems in oxygenic photosynthetic organisms, irrespective of the special-pair chlorophylls.

Allakhverdiev, Suleyman I.; Tomo, Tatsuya; Shimada, Yuichiro; Kindo, Hayato; Nagao, Ryo; Klimov, Vyacheslav V.; Mimuro, Mamoru

2010-01-01

369

Evolution of the M gene of the influenza A virus in different host species: large-scale sequence analysis  

PubMed Central

Background Influenza A virus infects not only humans, but also other species including avian and swine. If a novel influenza A subtype acquires the ability to spread between humans efficiently, it could cause the next pandemic. Therefore it is necessary to understand the evolutionary processes of influenza A viruses in various hosts in order to gain better knowledge about the emergence of pandemic virus. The virus has segmented RNA genome and 7th segment, M gene, encodes 2 proteins. M1 is a matrix protein and M2 is a membrane protein. The M gene may be involved in determining host tropism. Besides, novel vaccines targeting M1 or M2 protein to confer cross subtype protection have been under development. We conducted the present study to investigate the evolution of the M gene by analyzing its sequence in different species. Results Phylogenetic tree revealed host-specific lineages and evolution rates were different among species. Selective pressure on M2 was stronger than that on M1. Selective pressure on M1 for human influenza was stronger than that for avian influenza, as well as M2. Site-by-site analyses identified one site (amino acid position 219) in M1 as positively selected in human. Positions 115 and 121 in M1, at which consensus amino acids were different between human and avian, were under negative selection in both hosts. As to M2, 10 sites were under positive selection in human. Seven sites locate in extracellular domain. That might be due to host's immune pressure. One site (position 27) positively selected in transmembrane domain is known to be associated with drug resistance. And, two sites (positions 57 and 89) locate in cytoplasmic domain. The sites are involved in several functions. Conclusion The M gene of influenza A virus has evolved independently, under different selective pressure on M1 and M2 among different hosts. We found potentially important sites that may be related to host tropism and immune responses. These sites may be important for evolutional process in different hosts and host adaptation.

Furuse, Yuki; Suzuki, Akira; Kamigaki, Taro; Oshitani, Hitoshi

2009-01-01

370

Hemispheric Lateralization of Event-Related Brain Potentials in Different Processing Phases during Unimanual Finger Movements  

Microsoft Academic Search

Previous functional MRI and brain electrophysiology studies have studied the left-right differences during the tapping tasks and found that the activation of left hemisphere was more significant than that of right hemisphere. In this study, we wanted to delineate this lateralization phenomenon not only i n the execution phase but also in other processing phases, such as early visual, pre-execut

Ling-Fu Meng; Chiu-Ping Lu; Yi-Wen Li

2008-01-01

371

Properties of nanofibrillated cellulose from different raw materials and its reinforcement potential  

Microsoft Academic Search

Five commercial wood and wheat straw fiber sources with different morphologies were mechanically disintegrated into nanofibrillated cellulose (NFC). The processing times for disintegration varied, depending on the sizes and the moisture content of the starting materials. A decrease in polymerization degree (DP) for the fibrillated materials between 15% and 63% could be observed. Nevertheless, all isolated NFC materials showed homogenous

Tanja Zimmermann; Nicolae Bordeanu; Esther Strub

2010-01-01

372

Difference, Ambiguity and Potential for Learning--Local Communities Working in Partnership with Local Government.  

ERIC Educational Resources Information Center

An action learning project for neighborhood regeneration in Coventry, England, showed that differences of power and viewpoint were inevitable and essential. More open networks enabling communication among community groups were needed. Funding for community networking needed to go beyond short-term projects supported by the current policy agenda.…

Blaxter, Loraine; Farnell, Richard; Watts, Jane

2003-01-01

373

Evaluation of post-ERCP pancreatitis: potential causes noted during controlled study of differing contrast media  

Microsoft Academic Search

Background: Possible sources of post-ERCP pancreatitis were evaluated during a prospective, randomized, controlled study comparing different contrast media. Methods: A total of 1979 patients were randomized and subdivided into groups during the study. Patients were grouped for comparison depending on the type of procedure performed during ERCP. Diagnostic patients studied with pancreatograms (Group I) were compared with other groups, specifically,

G. Kenneth Johnson; Joseph E. Geenen; John F. Johanson; Stuart Shermal; Walter J. Hogan; Oliver Cass

1997-01-01

374

Geothrix fermentans Secretes Two Different Redox-Active Compounds To Utilize Electron Acceptors across a Wide Range of Redox Potentials  

PubMed Central

The current understanding of dissimilatory metal reduction is based primarily on isolates from the proteobacterial genera Geobacter and Shewanella. However, environments undergoing active Fe(III) reduction often harbor less-well-studied phyla that are equally abundant. In this work, electrochemical techniques were used to analyze respiratory electron transfer by the only known Fe(III)-reducing representative of the Acidobacteria, Geothrix fermentans. In contrast to previously characterized metal-reducing bacteria, which typically reach maximal rates of respiration at electron acceptor potentials of 0 V versus standard hydrogen electrode (SHE), G. fermentans required potentials as high as 0.55 V to respire at its maximum rate. In addition, G. fermentans secreted two different soluble redox-active electron shuttles with separate redox potentials (?0.2 V and 0.3 V). The compound with the lower midpoint potential, responsible for 20 to 30% of electron transfer activity, was riboflavin. The behavior of the higher-potential compound was consistent with hydrophilic UV-fluorescent molecules previously found in G. fermentans supernatants. Both electron shuttles were also produced when cultures were grown with Fe(III), but not when fumarate was the electron acceptor. This study reveals that Geothrix is able to take advantage of higher-redox-potential environments, demonstrates that secretion of flavin-based shuttles is not confined to Shewanella, and points to the existence of high-potential-redox-active compounds involved in extracellular electron transfer. Based on differences between the respiratory strategies of Geothrix and Geobacter, these two groups of bacteria could exist in distinctive environmental niches defined by redox potential.

Mehta-Kolte, Misha G.

2012-01-01

375

Finite-Difference Time-Domain Numerical Analysis of Elastic Wave Fields Using both Elastic and Velocity Potential Variables  

NASA Astrophysics Data System (ADS)

The use of both elastic variables and velocity potentials is proposed for the analysis of elastic wave fields in isotropic solids by finite-difference time-domain (FDTD) methods. The term ‘elastic variables’ refers to stresses and particle velocities. Velocity potentials can be directly derived using the same leap-frog finite-difference scheme as in the FDTD method. In some situations, for example, where an absorbing boundary is present, it is more straightforward to calculate using velocity potentials. This approach also provides an easy way to handle of complex elastic wave phenomena. On the other hand, many other types of boundary conditions are often expressed in terms of elastic variables. In these situations, it is more convenient to use elastic variables for calculation. Some examples are introduced here to illustrate the efficiency of the proposed technique. First, the method was used for the case of an absorbing boundary. In the model, almost all analysis was carried out using values of stress and particle velocity, but velocity potentials were applied near the absorbing boundary on the truncated interface. Second, an interface between elastic variables and velocity potentials, namely a stress-velocity/potentials interface, was constructed around a scattering object. External to the interface, stresses and particle velocities were used for calculation, and potential variables were applied inside the interface. In a third example, calculations were made over almost the entire analytical region using potential values, but in the neighborhood of the free boundary, elastic variables were used. All the examples above were analyzed numerically using the FDTD method, and the results confirmed the usefulness of the method.

Sato, Masahiro

2006-05-01

376

Different sensitivity of germinal center B cell-like diffuse large B cell lymphoma cells towards ibrutinib treatment  

PubMed Central

Background Although rituximab in the combination of CHOP chemotherapy has been widely used as the standard treatment for several kinds of B-cell non-Hodgkin lymphoma (B-NHL), a great number of B-NHL patients treated with this immunotherapy still develop primary and secondary resistance. Recently Bruton’s tyrosine kinase (Btk) inhibitor ibrutinib showed promising therapeutic effect in relapsed/refractory CLL and B-cell NHL, which provided essential alternatives for these patients. Methods The proliferation and apoptosis induction of tumor cells were measured by cell viability assay and Annexin-V staining. Western Blotting analysis and real-time PCR were used to detect the expression level of target proteins and chemokines production. Results We demonstrated that ibrutinib inhibited the proliferation and induced apoptosis of GCB-DLBCL cell lines through suppression of BCR signaling pathway and activation of caspase-3. Furthermore, the chemokines CCL3 and CCL4 production from tumor cells were also found to be attenuated by ibrutinib treatment. But different cell lines exhibited distinct sensitivity after ibrutinib treatment. Interestingly, the decreasing level of p-ERK after ibrutinib treatment, but not the basal expression level of Btk, correlated with different drug sensitivity. Conclusions Ibrutinib could be a potentially useful therapy for GCB-DLBCL and the decreasing level of p-ERK could become a useful biomarker to predict related therapeutic response.

2014-01-01

377

Different classes of CB2 ligands potentially useful in the treatment of pain.  

PubMed

The search of new drugs and targets to treat the pain is an intriguing challenge both for several companies and researchers from academia. In this context, since the modulation of the endocannabinoid system with the non selective phytocannabinoid ?9-THC produces analgesia and potentiates opioid analgesia in animal models, CB2 ligands studies aimed to explore the involvement of endocannabinoid system in management of pain were started. Several selective CB2 receptor agonists exhibited analgesic activity in preclinical models of acute, inflammatory and neuropathic pain, therefore this class of modulators could be useful as analgesic agents for pain, migraine, inflammation and osteoarthritis. This review is an update of our previously manuscript "A survey of recent patents on CB2 agonists in the management of pain" and provides an overview of patents and advances in CB2 agonist studies in the treatment of pain. PMID:23477308

Murineddu, Gabriele; Deligia, Francesco; Dore, Antonio; Pinna, Giovanni; Asproni, Battistina; Pinna, Gerard A

2013-04-01

378

Assessment of Self-Help Methods to Reduce Potential Exposure to Radiological Contamination after a Large-scale Radiological Release.  

PubMed

After the release of radioactive materials from a large radiological dispersal device (e.g., dirty bomb), improvised nuclear detonation, or nuclear power plant accident, up to hundreds of square miles may be contaminated. A portion of this area will be evacuated; however, people living in the portion that is not evacuated yet is still contaminated with low-levels of radioactive contamination will be asking for ways they can reduce their exposure. Whether cleaning activities can significantly reduce exposure is not fully understood. In this effort, the ability of cleaning activities to remove cesium (Cs) was studied. The removal efficacy of cleaning with a commercial product, Simple Green, was compared to cleaning with water for hard surfaces typically seen in residences. The removal efficacy of laundering fabric material surfaces was also determined for a range of conditions (e.g., fabric material type, wash temperature). During these studies, assessments of the implications of these activities (e.g., cross-contamination, resulting waste streams) were also completed. Simple Green and water were effective for removing Cs from plastic laminate and vinyl flooring (93.4-96.8%) but were not effective for removing Cs from painted wallboard and wood (7.3-68.1%). It was also determined that there was no significant difference between the two cleaners on all of the surfaces, except plastic laminate, for which Simple Green was slightly more effective. Laundering was effective for removing Cs contamination from polyester and cotton swatches and cotton comforters (up to 96.8% in the single swatch testing). PMID:25068960

Snyder, Emily; Drake, John; Cardarelli, John; Hall, Kathy; Szabo, Jeff; Demmer, Rick; Lindberg, Michael; Riggs, Karen; James, Ryan

2014-09-01

379

Genomic profiling of Richter's syndrome: recurrent lesions and differences with de novo diffuse large B-cell lymphomas.  

PubMed

Richter's syndrome (RS) represents the transformation of chronic lymphocytic leukaemia (CLL) to aggressive lymphoma and is mostly represented by diffuse large B-cell lymphoma (DLBCL), with a post-germinal centre (GC) phenotype, clonally related to the pre-existing CLL. RS has a very poor prognosis and its pathogenetic mechanisms are poorly understood. In order to gain additional hints in RS pathogenesis, we performed a genome-wide DNA profiling study of 13 RS phases and eight matched CLL phases using the Affymetrix Human Mapping 250K NspI SNP arrays. Individual genomic profiles were heterogeneous, with no individual lesions occurring in more than half of the cases. However, several observations suggest that MYC pathway might be involved in RS. The 13q13.3-qter region containing MIRHG1 (MIR-17-92), a cluster of microRNA interacting with c-MYC, was acquired at the time of transformation. The 13q gain was coupled with the gain of c-MYC and loss of TP53. Translocation of c-MYC was acquired at transformation in a fraction of cases and this event appeared mutually exclusive with gain of MIRHG1. MYCN, a c-MYC homologue, was also recurrently gained. By comparing RS with 48 de novo DLBCL, RS presented a significantly lower prevalence of deletions affecting the PRDM1 and TNFAIP3, genes on 6q, known to be associated with a post-GC phenotype. In conclusion, the genomic profile of RS seems to differ from what observed in de novo DLBCL and in other transformed DLBCL. Genomic lesions occurring in RS are heterogeneous suggesting the existence of different RS subsets, possibly due to different transforming mechanisms. A deregulation of MYC pathway might represent one of the main transformation events in the pathogenesis of a subset of RS clonally related to the previous CLL. PMID:20014148

Scandurra, Marta; Rossi, Davide; Deambrogi, Clara; Rancoita, Paola M V; Chigrinova, Ekaterina; Mian, Michael; Cerri, Michaela; Rasi, Silvia; Sozzi, Elisa; Forconi, Francesco; Ponzoni, Maurilio; Moreno, Santiago M; Piris, Miguel A; Inghirami, Giorgio; Zucca, Emanuele; Gattei, Valter; Rinaldi, Andrea; Kwee, Ivo; Gaidano, Gianluca; Bertoni, Francesco

2010-06-01

380

Differences in the RNA binding sites of iron regulatory proteins and potential target diversity.  

PubMed Central

Posttranscriptional regulation of genes of mammalian iron metabolism is mediated by the interaction of iron regulatory proteins (IRPs) with RNA stem-loop sequence elements known as iron-responsive elements (IREs). There are two identified IRPs, IRP1 and IRP2, each of which binds consensus IREs present in eukaryotic transcripts with equal affinity. Site-directed mutagenesis of IRP1 and IRP2 reveals that, although the binding affinities for consensus IREs are indistinguishable, the contributions of arginine residues in the active-site cleft to the binding affinity are different in the two RNA binding sites. Furthermore, although each IRP binds the consensus IRE with high affinity, each IRP also binds a unique alternative ligand, which was identified in an in vitro systematic evolution of ligands by exponential enrichment procedure. Differences in the two binding sites may be important in the function of the IRE-IRP regulatory system. Images Fig. 3

Butt, J; Kim, H Y; Basilion, J P; Cohen, S; Iwai, K; Philpott, C C; Altschul, S; Klausner, R D; Rouault, T A

1996-01-01

381

[Potential of ultrasound biomicroscopy of retinal periphery in cataract of different etiology].  

PubMed

Presence and pattern of peripheral retinal changes were studied using ultrasound biomicroscopy (UBM) in patients with cataract of different etiology. UBM was performed in 85 eyes of 65 patients. Mean age was 65, 75+8, 19 years old. UBM was performed using "Sonomed" equipment (USA). Morphology of revealed by means of UBM peripheral retinal changes was made in 5 eyes with uveal melanoma. The signs of retinoschisis were found in 82 eyes (96.5%) using UBM. The initial UBM signs represent inclusions in the inner retinal layers. With the progressing of schisis cystic splitting of retina was found. Confluence of distinct cysts into one schisis zone was characteristic for further progressing. Thus peripheral retinoschisis has acoustic stages, that are confirmed morphologicaly and can be revealed by means of UBM in the majority of old patients with cataract of different etiology. PMID:21882638

Takhchidi, Kh P; Egorova, É V; Uzunian, D G; Shatskikh, A V; Vinnik, N A

2011-01-01

382

[Adipogenic Potentials of Mesenchymal Stem Cells from Human Bone Marrow, Umbilical Cord and Adipose Tissue are Different].  

PubMed

Mesenchymal stem cells (MSCs) could be obtained from many sources, and there are differences between them. This study was purposed to compare and analyze the basic biological characteristes of umbilical cord, adipose tissue-and bone marrow-derived MSC (UC-MSCs, AD-MSCs and BM-MSCs). The MSCs were isoloted from umbilical cord, adipose tissue and bone marrow were cultured; the morphology of UC-MSCs, AD-MSCs and BM-MSCs was observed by using microscopy; the immunophenotype, differentiation potential and expression of peroxisome proliferation-activated receptor-? (PPAR-?) mRNA were detected by using flow cytometry, differentiation test (von kossais and 0:1 red O staining) and quantitative fluorescent PCR, respectively. The results showed that the UC-MSCs, AD-MSCs and BM-MSCs displayed similar morphology under confocal microscope after being stained with rhodamine phalloidin and DAPL. The immunophenotypes of these three originated cells comform to conincide with idetification criterion for MSCs, and showed similar expression level. During adipogenic induction the adipogenic potential of these MSCs was different, AD-MSCs exhibited the highest adipogenic potential, UC-MSCs displayed the lowest, while potential of BM-MSCs get between; however, the ostegenic differentiation potential of UC-MSCs, AD-MSCs and BM-MSCs was similar. The PCR detection showed that the expression level of PPAR-? mRNA was the highest in AD-MSCs and the lowest in UC-MSCs, while expression level in BM-MSCs get between, these results were identical with the adipogenic potential, suggest that the difference of adipogenic potential in 3 kinds of MSCs was associated with basic expression level of PPAR-? mRNA. It is concluded that UC-MSCs, AD-MSCs and BM-MSCs exhibite similar morphology, the immunophenotypes of these MSCs coincide with identification criterion for MSCs, the osteogenic potential of these MSCs is similar, while the adipogenic protential and the expression level of PPAR-? mRNA are different. The difference-associated mechanisms need to further study. PMID:24989259

Chi, Ying; Han, Zhi-Bo; Xu, Fang-Yun; Wang, You-Wei; Feng, Xiao-Ming; Chen, Fang; Ma, Feng-Xia; DU, Wen-Jing; Han, Zhong-Chao

2014-05-01

383

Gender Differences in Cholesterol Nucleation in Native Bile: Estrogen Is a Potential Contributory Factor  

Microsoft Academic Search

The incidence of gallstone disease is two to three times higher in women than in men, and female sex hormones, particularly\\u000a estrogens, have been implicated as contributory factors. Cholesterol nucleation is the initial step in gallstone pathogenesis\\u000a and proceeds from cholesterol-rich phospholipid vesicles. The aim of this study was to investigate if there is a difference\\u000a in cholesterol nucleation rates

Angela C. Brown; Steven P. Wrenn; Nandita Suresh; William C. Meyers; Mohammad Z. Abedin

2009-01-01

384

Evaluation of radical scavenging potential and total phenol content in Woodfordia fruticosa from different altitudes  

Microsoft Academic Search

Woodfordia fruticosa Kurz is a member of family Lythraceae, commonly used in the treatment of diseases like leucorrhoea, dysentery, leprosy and\\u000a menorrhagia. The plant material such as leaves, bark and flowers were collected from three different (200, 402 and 600 m)\\u000a altitudes of Khandala (M.S. India) and the extracts were prepared in solvents like methanol, ethanol and distilled water.\\u000a The radical

Palak Akshyesh Chaturvedi; Arindam Alok Ghatak; Neetin Shivajirao Desai

385

Thermoelectric Behavior of Sb- and Al-Doped n-Type Mg2Si Device Under Large Temperature Differences  

NASA Astrophysics Data System (ADS)

The thermoelectric (TE) characteristics of Sb- and Al-doped n-type Mg2Si elemental devices fabricated using material produced from molten commercial doped polycrystalline Mg2Si were examined. The TE devices were prepared using a plasma-activated sintering (PAS) technique. To complete the devices, Ni electrodes were fabricated on each end of them during the sintering process. To realize durable devices for large temperature differences, thermodynamically stable Sb-doped Mg2Si (Sb-Mg2Si) was exposed to the higher temperature and Al-doped Mg2Si (Al-Mg2Si) was exposed to the cooler temperature. The devices consisted of segments of Sb-Mg2Si and Al-Mg2Si with sizes in the following ratios: Sb-Mg2Si:Al-Mg2Si = 4:1, 1:1, and 1:4. A device specimen composed solely of Sb-Mg2Si showed no notable deterioration even after aging for 1000 h, while some segmented specimens, such as those with Sb-Mg2Si:Al-Mg2Si = 1:1 and 1:4, suffered from a considerable drop in output current over the large ? T range. The observed power generated by specimens with Sb-Mg2Si:Al-Mg2Si = 1:1 and 1:4 and sizes of 2 mm × 2 mm × 10 mm were 50.7 mW and 49.5 mW, respectively, with higher and lower temperatures of 873 K and 373 K, respectively. For the sample composed solely of Sb-Mg2Si, a power of 55 mW was demonstrated. An aging test for up to 1000 h for the same ? T range indicated drops in output power of between ˜3% and 20%.

Sakamoto, Tatsuya; Iida, Tsutomu; Kurosaki, Shota; Yano, Kenji; Taguchi, Hirohisa; Nishio, Keishi; Takanashi, Yoshifumi

2011-05-01

386

Potential for thermophilic (50 degrees C) anaerobic dechlorination of pentachlorophenol in different ecosystems.  

PubMed Central

Thermophilic (50 degrees C) anaerobic biodegradation of pentachlorophenol (PCP) was investigated by using different inocula from natural ecosystems and anaerobic digesters. The inocula tested were three freshwater sediments, four anaerobic sewage sludge samples from digesters treating sludge from wastewater plants with various industrial inputs, and digested manure from an anaerobic reactor. Only one digested-sludge sample and the manure sample were from thermophilic environments. The initial PCP concentration was 7.5 or 37.5 microM. After 8 months, PCP had disappeared from the sediment samples and various, less chlorinated intermediates were present. Additions of extra PCP were degraded within 4 weeks, and a maximal observed dechlorination rate of 1.61 mumol/liter/day in the vials with addition of 7.5 microM PCP and 7.50 mumol/liter/day in the vials with addition of 37.5 microM PCP were measured for a freshwater sediment. In contrast, only 2.8 to 17.5% of the initial PCP added had disappeared from the sludge samples after 8 months of incubation. The complex pattern of intermediates formed indicated that the dechlorination of PCP proceeded via different pathways, involving at least two different populations in the dechlorination processes.

Larsen, S; Hendriksen, H V; Ahring, B K

1991-01-01

387

Effects of different storage protocols on cat testis tissue potential for xenografting and recovery of spermatogenesis.  

PubMed

The loss of genetic diversity due to premature death of valuable individuals is a significant problem in animal conservation programs, including endangered felids. Testis tissue xenografting has emerged as a system to obtain spermatozoa from dead immature animals, however protocols to store this tissue before xenografting are still lacking. This study focused on testis tissue cryopreservation and storage from the domestic cat (Felis catus) classified as "pre-pubertal" and "pubertal" according to spermatogenesis development. Grafts from testis tissue cryopreserved with DMSO 1.4M, recovered after 10 weeks xenografting, presented seminiferous tubules with no germ cells. On the contrary, testis tissue from pre-pubertal animals preserved in ice-cold medium for 2 to 5 days presented no loss of viability or spermatogenic potential, while the number of grafts of pubertal cat testis tissue with germ cells after 10 weeks of xenografting decreased with increasing storage time. Nevertheless, even grafts from pre-pubertal cat testis tissue presented lower anti-DDX4 and anti-BOULE staining (proteins necessary for the meiosis completion), when compared with adult cat testis. Finally, a strong correlation found between testis weight and xenograft outcome may help choose good candidates for xenografting. PMID:21958640

Mota, Paula C; Ehmcke, Jens; Westernströer, Birgit; Gassei, Kathrin; Ramalho-Santos, João; Schlatt, Stefan

2012-01-15

388

In vitro Evaluation of Different Feeds for Their Potential to Generate Methane and Change Methanogen Diversity  

PubMed Central

Optimization of the dietary formulation is the most effective way to reduce methane. Nineteen feed ingredients (brans, vegetable proteins, and grains) were evaluated for their potential to generate methane and change methanogen diversity using an in vitro ruminal fermentation technique. Feed formulations categorized into high, medium and low production based on methane production of each ingredient were then subjected to in vitro fermentation to determine the real methane production and their effects on digestibility. Methanogen diversity among low, medium and high-methane producing groups was analyzed by PCR-DGGE. The highest methane production was observed in Korean wheat bran, soybean and perilla meals, and wheat and maize of brans, vegetable protein and cereal groups, respectively. On the other hand, corn bran, cotton seed meal and barley led to the lowest production in the same groups. Nine bacteria and 18 methanogen 16s rDNA PCR-DGGE dominant bands were identified with 83% to 99% and 92% to 100% similarity, respectively. Overall, the results of this study showed that methane emissions from ruminants can be mitigated through proper selection o