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1

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.

Steven Maier

2

Large data analysis of different sensory modalities  

NASA Astrophysics Data System (ADS)

We exam the historical remote digital video and in situ analog acoustic data analyses from the modern Large Data Analysis standpoint. We discussed a potential automation from traditional search engine to modern one. We exam the mathematic theory to answer where the nonlinear dimensional analysis assume a local flat space where linear eigenvalue provided the independent components, then the component is extrapolated to original nonlinear space and assume the local flat reduction remains meaningful at global nonlinear domain.

Hsu, Ming-Kai; Szu, Harold

2014-05-01

3

Modelling Oscillations of Membrane Potential Difference  

Microsoft Academic Search

The oscillation of the membrane potential difference (PD) is considered in terms of one or more ion transporters changing their conductances. For slow oscillations (period greater than about one minute), the transporters could be identified by employing the current–voltage (I\\/V) technique. The electrical characteristics of each transporter population were then modeled and the evolution of the model parameters with time

MARY JANE BEILBY

4

Measurement of ground potential difference at power substations  

SciTech Connect

Increasing sensitivity of electronic equipment, such as the integrated services digital network, and closer association of telephone and power facilities increase the importance of an accurate determination of ground potential difference (GPD) during a ground fault in or near a power substation. A method of recording actual values of GPD using six years of records at four large substations is presented and analyzed.

Lipavsky, P. (Cincinnati Bell Telephone, Cincinnati, OH (US)); Nienaber, R.E. (Cincinnati Gas and Electric Co., OH (USA))

1991-01-01

5

Thermodynamics of QCD at large quark chemical potential  

E-print Network

We review the existing weak-coupling results on the thermodynamic potential of deconfined QCD at small and large quark chemical potential and compare with results from lattice gauge theory as well as the exactly solvable case of large-N_f QCD. We also discuss the new analytical results on non-Fermi-liquid effects in entropy and specific heat as well as in dispersion laws of quark quasiparticles at large quark chemical potential.

Andreas Gerhold; Andreas Ipp; Anton Rebhan

2005-12-21

6

Resolvent estimates for perturbations by large magnetic potentials  

SciTech Connect

We prove optimal high-frequency resolvent estimates for self-adjoint operators of the form G = ?? + ib(x) · ? + i? · b(x) + V(x) on L{sup 2}(R{sup n}), 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, E-mail: fernando@dmat.ufpe.br; Cuevas, Claudio, E-mail: cch@dmat.ufpe.br [Departamento de Matemática, Universidade Federal de Pernambuco, CEP. 50540-740 Recife-Pe (Brazil)] [Departamento de Matemática, Universidade Federal de Pernambuco, CEP. 50540-740 Recife-Pe (Brazil); Vodev, Georgi, E-mail: vodev@math.univ-nantes.fr [Département de Mathématiques, Université de Nantes, UMR 6629 du CNRS, 2, rue de la Houssinière, BP 92208, 44332 Nantes Cedex 03 (France)] [Département de Mathématiques, Université de Nantes, UMR 6629 du CNRS, 2, rue de la Houssinière, BP 92208, 44332 Nantes Cedex 03 (France)

2014-02-15

7

Cadmium phytoextraction potential of different Alyssum species  

Microsoft Academic Search

This work was planned for providing useful information about the possibility of using serpentine adapted plants for phytoextraction of cadmium, element scarcely represented in such metalliferous environment. To this aim, we investigated variation in cadmium tolerance, accumulation and translocation in three Alyssum plants with different phenotypes: Alyssum bertolonii, that is a serpentine endemic nickel hyperaccumulator, and two populations of Alyssum

R. Barzanti; I. Colzi; M. Arnetoli; A. Gallo; S. Pignattelli; R. Gabbrielli; C. Gonnelli

2011-01-01

8

Large wind turbine generators. [NASA program status and potential costs  

NASA Technical Reports Server (NTRS)

The large wind turbine portion of the Federal Wind Energy Program consists of two major project efforts: (1) the Mod-0 test bed project for supporting research technology, and (2) the large experimental wind turbines for electric utility applications. The Mod-0 has met its primary objective of providing the entire wind energy program with early operations and performance data. The large experimental wind turbines to be tested in utility applications include three of the Mod-0A (200 kW) type, one Mod-1 (2000 kW), and possibly several of the Mod-2 (2500 kW) designs. This paper presents a description of these wind turbine systems, their programmatic status, and a summary of their potential costs.

Thomas, R. L.; Donovon, R. M.

1978-01-01

9

NUMERICAL CALIBRATION OF ELECTRIC POTENTIAL DIFFERENCE FOR CRACK SIZE MONITORING  

Microsoft Academic Search

The electric potential difference technique is frequently used to monitor crack size propagation in fatigue testing. Crack size is indirectly measured by the change of the electrical field, due to the crack discontinuity, when the component on test is exposed to an electric current flowing through it. The potential difference can be related to crack size through experimental, analytical or

R. A. CLÁUDIO; C. M. BRANCO

10

Energy potential and early operational experience for large wind turbines  

NASA Technical Reports Server (NTRS)

Projections for the total potential output of large wind turbines in the U.S. are reviewed. NASA has developed nine large windpowered generators, of 100 kW, 200 kW, 2 MW, and 2.5 MW capacities, with rotors 100-300 ft in diameter, and all with horizontal axes. Approximately 214,000 sq miles of the U.S. have been determined as having substantial wind regimes and terrain suitable for large wind turbine siting. This translates into 340,000 Mod 2 (2.5 MW) wind turbines producing 4.9 quads of electricity annually, equivalent to saving 2.5 billion barrels of oil/yr. The cost of electricity is seen as the critical factor in utility acceptance of large wind turbines, and the Mod 2 machines are noted to achieve the 2-4 cents/kWh (1977 dollars) COE which is necessary. Problems such as pollution, including visual, auditory, EM, and land use difficulties are considered, and solutions are indicated.

Robbins, W. H.; Thomas, R. L.

1980-01-01

11

Mixing device for materials with large density differences  

DOEpatents

An auger-tube pump mixing device 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.

Gregg, David W. (Moraga, CA)

1994-01-01

12

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

13

Finite difference methods for the solution of unsteady potential flows  

NASA Technical Reports Server (NTRS)

Various problems which are confronted in the development of an unsteady finite difference potential code are reviewed mainly in the context of what is done for a typical small disturbance and full potential method. The issues discussed include choice of equations, linearization and conservation, differencing schemes, and algorithm development. A number of applications, including unsteady three dimensional rotor calculations, are demonstrated.

Caradonna, F. X.

1982-01-01

14

A micropump based on water potential difference in plants  

Microsoft Academic Search

In land plants, water vapor diffuses into the air through the stomata. The loss of water vapor creates a water potential difference\\u000a between the leaf and the soil, which draws the water upward. Quantitatively, the water potential difference is 1–2 MPa which\\u000a can support a water column of 100–200 m. Here we present the design and operation of a biomimetic micropump. The

Jing Min Li; Chong Liu; Kai Ping Zhang; Xue Ke; Zheng Xu; Chun Yu Li; Li Ding Wang

15

Large and small color differences: predicting them from hue scaling  

NASA Astrophysics Data System (ADS)

Color appearance can be specified by a procedure of direct hue scaling. In this procedure, subjects look at a stimulus and then simply state the proportions of their sensations using the four unique hue names red, yellow, green, and blue; to completeness, they also state the apparent saturation. Observers can scale stimuli quickly and reliably, and this is true even if they are relatively inexperienced. Thus stimuli can be rescaled whenever viewing conditions change such that a new specification of appearance is required. The scaled sensory values elicited by a set of stimuli are used to derive the locations of the stimuli on a color diagram that is based on appearance and which we term a Uniform Appearance Diagram (UAD). The orthogonal axes of these space are red-green and yellow-blue; the location of a stimulus specifies its hue and its distance from the origin specifies its apparent saturation. We have investigated the uniformity of this space by using a subject's UAD, for a particular set of viewing conditions, to predict both small and large color differences under comparable viewing conditions. For small-scale differences we compared wavelength discrimination functions derived from UADs with those obtained by direct adjustment of a bipartite field. For large-scale differences, subjects rated the degree of similarity of pairs of different wavelengths; these ratings were compared with the distances separating the same pairs of wavelengths on a UAD. In both cases, the agreements were very good, implying that UAD's are metrically uniform. Thus, UADs could be used to adjust the hues in a pseudo-color display so that all transitions would be equally perceptible or would differ by specified amounts.

Chan, Hoover; Abramov, Israel; Gordon, James

1991-06-01

16

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

17

Finite difference methods for the solution of unsteady potential flows  

NASA Technical Reports Server (NTRS)

A brief review is presented of various problems which are confronted in the development of an unsteady finite difference potential code. This review is conducted mainly in the context of what is done for a typical small disturbance and full potential methods. The issues discussed include choice of equation, linearization and conservation, differencing schemes, and algorithm development. A number of applications including unsteady three-dimensional rotor calculation, are demonstrated.

Caradonna, F. X.

1985-01-01

18

Oral potentially malignant disorders in a large dental population.  

PubMed

Objectives Oral cancer (OC) may be preceded by clinically evident oral potentially malignant disorders (OPMDs). Oral carcinogenesis is a multistep process that begins as epithelial hyperplasia and progresses to oral epithelial dysplasia and finally to fully malignant phenotypes. The aim of our study was to estimate the prevalence of OPMDs in a large population of dental patients. Methods Patients were seen in the Oral Diagnosis and Oral Medicine clinics at Boston University Henry M. Goldman School of Dental Medicine between July 2013 and February 2014 and received a comprehensive oral examination to identify any possible mucosal lesions. Patients with a suspected OPMD (submucous fibrosis, oral lichen planus, leukoplakia and erythroplakia) that did not resolve in 2-3 weeks received a biopsy for definitive diagnosis. Logistic regression models were used to explore the relationship between OPMDs and associated risk factors. Results A total of 3,142 patients received a comprehensive oral examination [median age: 43 (range: 18-97); 54.3% females]. Among these, 4.5% had an oral mucosal lesion with 0.9% being an OPMD (one submucous fibrosis, three epithelial dysplasias, fourteen with hyperkeratosis/epithelial hyperplasia and nine with oral lichen planus). Males and current smokers were associated with higher odds of having OPMD (OR 1.7, 95% CI 0.8-3.8; OR 1.9, 95%CI 0.8-4.1). Increasing age was associated with having OPMDs (p<0.01). Conclusion Optimal oral visual screening for OC remains a simple and essential tool to identify any suspicious lesions and potentially increase survival. Although OPMDs were rare, our results confirm the importance of a thorough chairside screening by dentists and dental students to detect any mucosal changes. PMID:25591015

Villa, Alessandro; Gohel, Anita

2014-12-01

19

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

20

Energetic recoils in UO2 simulated using five different potentials.  

PubMed

This report presents the results of classical molecular dynamics simulations of the diffuse premelting transition, melting, and defect production by 1 keV U recoils in UO(2) using five different rigid ion potentials. The experimentally observed premelting transition occurred for all five cases. For all the potentials studied, dynamic defect annealing is highly effective and is accompanied by replacement events on the anion sublattice. The primary damage state after approximately 15 ps consists of isolated Frenkel pairs and interstitial and vacancy clusters of various sizes. The average displacement energy varies from approximately 28 to approximately 83 eV and the number of Frenkel pairs is different by a factor of 3 depending on the choice of potential. The size and spatial distribution of vacancy and interstitial clusters is drastically different for the potentials studied. The results provide statistics of defect production. They point to a pressing need to determine defect formation, migration, and binding energies in UO(2) from first principles and to develop reliable potentials based on this data for simulating microstructural evolution in nuclear fuel under operating conditions. PMID:19425785

Devanathan, Ram; Yu, Jianguo; Weber, William J

2009-05-01

21

Abnormalities of nasal potential difference measurement in Liddle's syndrome.  

PubMed Central

In Liddle's syndrome, a rare inherited form of hypertension, epithelial sodium channel mutations appear to cause high blood pressure by increasing sodium reabsorption through sodium channels in the renal distal tubule. This increase in channel activity has not been confirmed previously by in vivo measurement. We have made transnasal potential difference measurements (effective in detection of increased sodium channel activity in cystic fibrosis) in three brothers with genetically proven Liddle's syndrome, their unaffected sister, and 40 normotensive controls. Maximum potential difference after 2 wk off treatment in the affected brothers was -30.4+/-1.2 mV (values mean+/-SD, lumen-negative with respect to submucosa) and was significantly more lumen-negative than that of the control group (-18.6+/-6.8 mV, P = 0.0228) or the unaffected sister (-18.25 mV, P < 0.01). The change in potential difference after topical application of 10(-)4 M amiloride was greater in the Liddle's patients, 14.0+/-2.1 mV, than in controls (7.9+/-3.9 mV, P = 0.0126) or the unaffected sister (5.5 mV, P < 0.05). This is the first in vivo demonstration of increased sodium channel activity in Liddle's syndrome. If these results are confirmed in other kindreds with this condition, then nasal potential difference measurements could provide a simple clinical test for Liddle's syndrome. PMID:9649551

Baker, E; Jeunemaitre, X; Portal, A J; Grimbert, P; Markandu, N; Persu, A; Corvol, P; MacGregor, G

1998-01-01

22

Antioxidant potential of different plum cultivars during storage.  

PubMed

Plums, the most commonly consumed fruits from Romania, are fruits rich in bioactive compounds, such as antioxidants. This research work was carried out to investigate the antioxidant potential of twelve plum cultivars, fresh and stored during 10days at 4°C by using different methods (DPPH, ORAC and erythrocyte resistance to haemolysis). The contents of total phenolic compounds and total anthocyanins were also determined by specific spectrometric methods. Significant differences between fresh and stored plum cultivars (p<0.05) were found. Storage at 4°C resulted in an increase in antioxidant potential and anthocyanins content of the autumn plum varieties. Autumn plum varieties also showed a higher antioxidant capacity than summer varieties, as assessed by the ORAC and the haemolysis resistance assays. Our results suggest that, even after storage, plums could be a good source of antioxidants, which may provide health-promoting effects for humans. PMID:24176372

Mihalache Arion, Cristina; Tabart, Jessica; Kevers, Claire; Niculaua, Marius; Filimon, R?zvan; Beceanu, Dumitru; Dommes, Jacques

2014-03-01

23

Acylglycerol structure of peanut oils of different atherogenic potential  

Microsoft Academic Search

Detailed investigation was made of the triacylglycerol structure of native, simulated, and interesterified peanut oils, which\\u000a had previously been shown to differ markedly in their atherogenic potential. By means of chromatographic and stereospecific\\u000a analyses, it was shown that the more atherogenic native oil contains a significantly greater proportion of triacylglycerols\\u000a with linoleic insn-2-position and arachidic, behenic, and lignoceric acids insn-3-position

J. J. Myher; L. Marai; A. Kuksis; D. Kritchevsky

1977-01-01

24

Event-related potentials to different feedback stimuli.  

PubMed

Event-related potentials (ERPs) were recorded in a time estimation task under different feedback conditions, in which the informative value of the feedback signals (true versus false) was manipulated. A control condition was added in which no signal was presented. Fifteen subjects pressed a button 3 seconds after presentation of a warning signal. Two seconds after the response, a visual feedback signal was presented, indicating whether the preceding interval was estimated correctly. Two different slow waves were observed: the response was preceded by a readiness potential and the feedback stimulus was preceded by a negative slow wave called the stimulus-preceding negativity. The readiness potential was not influenced by the different feedback conditions. The stimulus-preceding negativity was larger in the true feedback condition compared to the false feedback and no feedback conditions. The P300 to the feedback signal was also larger following a true as compared to a false feedback signal. The conclusion is that the stimulus-preceding negativity is an anticipatory component contingent upon the presentation of an informative feedback signal. PMID:1946878

Chwilla, D J; Brunia, C H

1991-03-01

25

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

26

Molecular dynamics simulations of stretched gold nanowires: The relative utility of different semiempirical potentials  

NASA Astrophysics Data System (ADS)

The mechanical elongation of a finite gold nanowire has been studied by molecular dynamics simulations using different semiempirical potentials for transition metals. These potentials have been widely used to study the mechanical properties of finite metal clusters. Combining with density functional theory calculations along several atomic-configuration trajectories predicted by different semiempirical potentials, the authors conclude that the second-moment approximation of the tight-binding scheme (TB-SMA) potential is the most suitable one to describe the energetics of finite Au clusters. They find that for the selected geometries of Au wires studied in this work, the ductile elongation of Au nanowires along the [001] direction predicted by the TB-SMA potential is largely independent of temperature in the range of 0.01-298K. The elongation leads to the formation of monatomic chains, as has been observed experimentally. The calculated force-versus-elongation curve is remarkably consistent with available experimental results.

Pu, Qing; Leng, Yongsheng; Tsetseris, Leonidas; Park, Harold S.; Pantelides, Sokrates T.; Cummings, Peter T.

2007-04-01

27

Molecular dynamics simulations of stretched gold nanowires: the relative utility of different semiempirical potentials.  

PubMed

The mechanical elongation of a finite gold nanowire has been studied by molecular dynamics simulations using different semiempirical potentials for transition metals. These potentials have been widely used to study the mechanical properties of finite metal clusters. Combining with density functional theory calculations along several atomic-configuration trajectories predicted by different semiempirical potentials, the authors conclude that the second-moment approximation of the tight-binding scheme (TB-SMA) potential is the most suitable one to describe the energetics of finite Au clusters. They find that for the selected geometries of Au wires studied in this work, the ductile elongation of Au nanowires along the [001] direction predicted by the TB-SMA potential is largely independent of temperature in the range of 0.01-298 K. The elongation leads to the formation of monatomic chains, as has been observed experimentally. The calculated force-versus-elongation curve is remarkably consistent with available experimental results. PMID:17444732

Pu, Qing; Leng, Yongsheng; Tsetseris, Leonidas; Park, Harold S; Pantelides, Sokrates T; Cummings, Peter T

2007-04-14

28

Large potential steps at weakly interacting metal-insulator interfaces  

NASA Astrophysics Data System (ADS)

Potential steps exceeding 1 eV are regularly formed at metal|insulator interfaces, even when the interaction between the materials at the interface is weak physisorption. From first-principles calculations on metal|h -BN interfaces we show that these potential steps are only indirectly sensitive to the interface bonding through the dependence of the binding energy curves on the van der Waals interaction. Exchange repulsion forms the main contribution to the interface potential step in the weakly interacting regime, which we show with a simple model based upon a symmetrized product of metal and h -BN wave functions. In the strongly interacting regime, the interface potential step is reduced by chemical bonding.

Bokdam, Menno; Brocks, Geert; Kelly, Paul J.

2014-11-01

29

Large-time dynamics and aging of a polymer chain in a random potential.  

PubMed

We study the out-of-equilibrium large-time dynamics of a Gaussian polymer chain in a quenched random potential. The dynamics studied is a simple Langevin dynamics commonly referred to as the Rouse model. The equations for the two-time correlation and response functions are derived within the Gaussian variational approximation. In order to implement this approximation faithfully, we employ the supersymmetric representation of the Martin-Siggia-Rose dynamical action. For a short-ranged correlated random potential the equations are solved analytically in the limit of large times using certain assumptions concerning the asymptotic behavior. Two possible dynamical behaviors are identified depending upon the time separation: a stationary regime and an aging regime. In the stationary regime time translation invariance holds and so does the fluctuation dissipation theorem. The aging regime which occurs for large time separations of the two-time correlation functions is characterized by a history dependence and the breakdown of certain equilibrium relations. The large-time limit of the equations yields equations among the order parameters that are similar to the equations obtained in statics using replicas. In particular the aging solution corresponds to the broken replica solution. But there is a difference in one equation that leads to important consequences for the solution. The stationary regime corresponds to the motion of the polymer inside a local minimum of the random potential, whereas in the aging regime the polymer hops between different minima. As a by-product we also solve exactly the dynamics of a chain in a random potential with quadratic correlations. PMID:17025463

Goldschmidt, Yadin Y

2006-08-01

30

Potential role of large oceanic diatoms in new primary production  

NASA Astrophysics Data System (ADS)

Very large phytoplankton species >50 ?m in size, particularly diatoms, generally are found in background numbers throughout the euphotic zone of oceanic waters. Yet, when responding to episodic injections of new nutrients across the nutricline at the base of the euphotic zone these phototrophs may make a disproportionately large contribution to new primary production. To test this concept, we isolated a group of large diatoms from the Sargasso Sea and found that the specific growth rate of several of these species in culture was great enough at the ?2% light level in oligotrophic waters to meet the requirements of several hypothetical scenarios in which annual rates of new production from the sum of one or more episodic blooms were equal to contemporary estimates. Two of the fast-growing species, Stephanopyxis palmeriana (Greville) Grunow and Pseudoguinardia recta von Stosch, formed giant flocculant masses while growing. Such masses could sink rapidly out of the euphotic zone or be a direct food source for invertebrates or fish higher up the food chain. Not only would a short, simple trophic system with low losses result, but the events would virtually be impossible to observe with conventional sampling.

Goldman, Joel C.

1993-01-01

31

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.

32

Floating potential of large dust grains with electron emission  

SciTech Connect

Electron emission from the surface of solid particles plays an important role in many dusty plasma phenomena and applications. Examples of such cases include fusion plasmas and dusty plasma systems in our solar system. Electron emission complicates the physics of the plasma-dust interaction. One of the most important aspects of the physics of the dust plasma interaction is the calculation of the particle's floating potential. This is the potential a dust particle acquires when it is in contact with a plasma and it plays a very important role for determining its dynamical behaviour. The orbital motion limited (OML) approach is used in most cases in the literature to model the dust charging physics. However, this approach has severe limitations when the size of the particles is larger than the electron Debye length ?{sub De}. Addressing this shortcoming for cases without electron emission, a modified version of OML (MOML) was developed for modelling the charging physics of dust grains larger than the electron Debye length. In this work, we will focus on extending MOML in cases where the particles emit electrons. Furthermore, a general method for calculating the floating potential of dust particles with electron emission will be presented for a range of grain sizes.

Bacharis, M., E-mail: minas.bacharis03@imperial.ac.uk [Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BW (United Kingdom)

2014-07-15

33

Nasal Potential Difference in Cystic Fibrosis considering Severe CFTR Mutations  

PubMed Central

The gold standard for diagnosing cystic fibrosis (CF) is a sweat chloride value above 60?mEq/L. However, this historical and important tool has limitations; other techniques should be studied, including the nasal potential difference (NPD) test. CFTR gene sequencing can identify CFTR mutations, but this method is time-consuming and too expensive to be used in all CF centers. The present study compared CF patients with two classes I-III CFTR mutations (10 patients) (G1), CF patients with classes IV-VI CFTR mutations (five patients) (G2), and 21 healthy subjects (G3). The CF patients and healthy subjects also underwent the NPD test. A statistical analysis was performed using the Mann-Whitney, Kruskal-Wallis, ?2, and Fisher's exact tests, ? = 0.05. No differences were observed between the CF patients and healthy controls for the PDMax, ?amiloride, and ?chloride + free + amiloride markers from the NPD test. For the finger value, a difference between G2 and G3 was described. The Wilschanski index values were different between G1 and G3. In conclusion, our data showed that NPD is useful for CF diagnosis when classes I-III CFTR mutations are screened. However, if classes IV-VI are considered, the NPD test showed an overlap in values with healthy subjects.

Ng, Ronny Tah Yen; Marson, Fernando Augusto de Lima; Ribeiro, Jose Dirceu; Ribeiro, Antonio Fernando; Bertuzzo, Carmen Silvia; Ribeiro, Maria Angela Gonçalves de Oliveira; Severino, Silvana Dalge; Sakano, Eulalia

2015-01-01

34

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. PMID:18288540

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

2008-01-01

35

Scaling differences between large interplate and intraplate earthquakes  

NASA Technical Reports Server (NTRS)

A study of large intraplate earthquakes with well determined source parameters shows that these earthquakes obey a scaling law similar to large interplate earthquakes, in which M sub o varies as L sup 2 or u = alpha L where L is rupture length and u is slip. In contrast to interplate earthquakes, for which alpha approximately equals 1 x .00001, for the intraplate events alpha approximately equals 6 x .0001, which implies that these earthquakes have stress-drops about 6 times higher than interplate events. This result is independent of focal mechanism type. This implies that intraplate faults have a higher frictional strength than plate boundaries, and hence, that faults are velocity or slip weakening in their behavior. This factor may be important in producing the concentrated deformation that creates and maintains plate boundaries.

Scholz, C. H.; Aviles, C. A.; Wesnousky, S. G.

1985-01-01

36

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

37

Biomass Potentials in Different Maintenance Scenarios of Satoyama Woodlands  

NASA Astrophysics Data System (ADS)

Woodlands near human settlements often have long histories of providing people with fuelwood and other organic materials. In Japan, these woodlands are called satoyama. While satoyama woodlands were historically coppiced to provide an essential source of fuelwood, many have been developed into residential areas as a result of the introduction of fossil fuels beginning in the 1960's. Remaining satoyamas were simply abandoned due to the loss of economic value from fuelwood. This has resulted in a loss of other satoyama-related functions such as their ecological function. In response to the abandonment of satoyamas, thousands of volunteer groups have formed since the 1990's to restore satoyama woodlands. However, in spite of the importance of grassroots volunteers, their actual activities are limited in spatial extent due to shortages of manpower, time, and maintenance skill. This suggests that more substantial incentives are necessary, if maintenance of satoyama woodlands is to be extended. This study focused on an increased attention of biomass enegy utilization from satoyama trees as a promising incentive, and estimated biomass potentials in different maintenance scenarios of satoyama woodlands through a case study site in peri-urban Tokyo. This study set four maintenance scenarios; a) ground cover removal, b) light-thinning, c) intensive-thinning, and d) rotational coppicing. Based on the scenarios, the amount of biomass obtained, bioenergy generated, and carbon reduced were estimated respectively by the combination of conducting tree measurement and applying a long-term forest dynamics estimation model. Since there is tradeoff between CO2 reduction through woodenergy utilization and CO2 fixation by standing trees, these two variables were analyzed in tandem. The scenario that produces the most woody biomass was rotational coppicing, the maintenance scenario which also mimics historical management regimes. Despite the lowest potential of CO2 fixation by standing trees, the best scenario to reduce carbon was also rotational coppicing, due to the highest potential of CO2 reduction by woodenergy utilization. The result suggests that rotational coppicing, which mimics historical management, can also serve contemporary ends. Rotational coppicing can be promoted from the policies related to carbon reduction, but at the same time, further studies for clarifying the optimum degree of human disturbance (e.g. frequency of tree cutting, groundcover removal) are necessary to avoid negative impacts to forest ecosystems.

Terada, T.

2012-04-01

38

Achievement Differences between Large and Small Schools in Texas  

ERIC Educational Resources Information Center

The purpose of this study was to determine whether there exists a relationship between student achievement in Texas, as measured by the Texas Assessment of Knowledge and Skills (TAKS) test, and the size of the high school at different socioeconomic levels. This study compared five size categories of Texas high schools to determine which size high…

Stewart, Lee

2009-01-01

39

APPROXIMATE REGISTRATION OF POINT CLOUDS WITH LARGE SCALE DIFFERENCES  

E-print Network

of objects is a basic task in many fields, including surveying, engineering, entertainment and cultural point spacing and almost the same scale. A different approach is the 4-points congruent sets (4PCS that the two models are already roughly aligned. To overcome the limitation w.r.t. scale (Corsini et al., 2013

Schindler, Konrad

40

Kinematic Morphology of Large-scale Structure: Evolution from Potential to Rotational Flow  

NASA Astrophysics Data System (ADS)

As an alternative way of describing the cosmological velocity field, we discuss the evolution of rotational invariants constructed from the velocity gradient tensor. Compared with the traditional divergence-vorticity decomposition, these invariants, defined as coefficients of characteristic equation of the velocity gradient tensor, enable a complete classification of all possible flow patterns in the dark-matter comoving frame, including both potential and vortical flows. Before shell-crossing, different categories of potential flow are highly associated with cosmic web structure, because of the coherent evolution of density and velocity. This correspondence is even preserved at some level when vorticity is generated after shell-crossing. The evolution from the potential to vortical flow can be traced continuously by these invariants. With the help of this tool, we show that the vorticity is generated in a particular way that is highly correlated with the large-scale structure. This includes a distinct spatial distribution and different types of alignment between cosmic web and vorticity direction for various vortical flows. Incorporating shell-crossing into closed dynamical systems is highly non-trivial, but we propose a possible statistical explanation for some of these phenomena relating to the internal structure of the three-dimensional invariants space.

Wang, Xin; Szalay, A. S.; Aragon-Calvo, M. A.; Neyrinck, M. C.; Eyink, G. L.

2014-01-01

41

Kinematic Morphology of Large-scale Structure: Evolution from Potential to Rotational Flow  

NASA Astrophysics Data System (ADS)

As an alternative way to describe the cosmological velocity field, we discuss the evolution of rotational invariants constructed from the velocity gradient tensor. Compared with the traditional divergence-vorticity decomposition, these invariants, defined as coefficients of the characteristic equation of the velocity gradient tensor, enable a complete classification of all possible flow patterns in the dark-matter comoving frame, including both potential and vortical flows. We show that this tool, first introduced in turbulence two decades ago, is very useful for understanding the evolution of the cosmic web structure, and in classifying its morphology. Before shell crossing, different categories of potential flow are highly associated with the cosmic web structure because of the coherent evolution of density and velocity. This correspondence is even preserved at some level when vorticity is generated after shell crossing. The evolution from the potential to vortical flow can be traced continuously by these invariants. With the help of this tool, we show that the vorticity is generated in a particular way that is highly correlated with the large-scale structure. This includes a distinct spatial distribution and different types of alignment between the cosmic web and vorticity direction for various vortical flows. Incorporating shell crossing into closed dynamical systems is highly non-trivial, but we propose a possible statistical explanation for some of the phenomena relating to the internal structure of the three-dimensional invariant space.

Wang, Xin; Szalay, Alex; Aragón-Calvo, Miguel A.; Neyrinck, Mark C.; Eyink, Gregory L.

2014-09-01

42

Separation of large mammalian ventricular myosin differing in ATPase activity.  

PubMed

To investigate a possible heterogeneity of human ventricular myosin, papillary muscles of patients with valvular dysfunction were examined using a modified native gel electrophoresis. Myosin was separated into 2 components termed VA and VB, whereby the VA to VB proportion appeared to depend on the ventricular load. The proportion of the faster migrating band VA was correlated (P<0.05) with end-diastolic pressure and the aortic pressure-cardiac index product. The regression based on these variables accounted for 67% of the variation in VA (R2=0.67). The VA proportion was, however, not significantly correlated with cardiac norepinephrine concentration. The ATPase activity of the 2 components of myosin was assessed from the Ca3(PO4)2 precipitation by incubating the gel in the presence of ATP and CaCl2. The ATPase activity of VA was 60% of that of VB. The VA and VB forms were observed also in the cat (31.4% VA), dog (32.1% VA), pig (28.5% VA), wild pig (33.7% VA), and roe deer (30.5% VA). VA and VB were not detected in the rat exhibiting the 3 isoforms V1, V2, and V3, rabbit (100% V3), and hare (86% V1). The data demonstrate a heterogeneity of large mammalian ventricular myosin, whereby an increased cardiac load appeared to be associated with a higher myosin VA proportion that exhibited a reduced ATPase activity. PMID:17612641

Rupp, Heinz; Maisch, Bernhard

2007-01-01

43

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. PMID:22086515

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

2011-01-01

44

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

45

A spectral/finite difference method for simulating large deformations of heterogeneous, viscoelastic materials  

E-print Network

A spectral/finite difference method for simulating large deformations of heterogeneous, finite difference methods, inhomogeneous media, numerical techniques, spectral methods, viscoelasticity difference method and uses the Eulerian formulation including objective derivatives of the stress tensor

Podladchikov, Yuri

46

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

47

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

48

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

49

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

SciTech Connect

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.

Tzonev, I.V.; DeMora, J.M.; Miley, G.H. [Univ. of Illinois, Urbana, IL (United States)

1995-12-31

50

The multiparameter control of carbon potential in large scale continuous dripping carburization furnace  

SciTech Connect

By the investigation of the effects on the carbon potential in a Large scale continuous dripping carburization furnace, this paper presents a new thought in which air was used as the control agent in the control of carbon potential. An advanced mathematical model of process control and a multiparameter control system were established. The system has been used in production and performed very well.

Liang, X.M.; Wang, Z. [Heat Treatment Plant of FAW, Chang Chun (China); Zhang, H. [Chang Chun Automotive Material Research Inst. (China)

1995-12-31

51

Quark number density at imaginary chemical potential and its extrapolation to large real chemical potential by the effective model  

E-print Network

We evaluate quark number densities at imaginary chemical potential by lattice QCD with clover-improved two-flavor Wilson fermion. The quark number densities are extrapolated to the small real chemical potential region by assuming some function forms. The extrapolated quark number densities are consistent with those calculated at real chemical potential with the Taylor expansion method for the reweighting factors. In order to study the large real chemical potential region, we use the two-phase model consisting of the quantum hadrodynamics model for the hadron phase and the entanglement-PNJL model for the quark phase. The quantum hadrodynamics model is constructed to reproduce nuclear saturation properties, while the entanglement-PNJL model reproduces well lattice QCD data for the order parameters such as the Polyakov loop, the thermodynamic quantities and the screening masses. Then, we calculate the mass-radius relation of neutron stars and explore the hadron-quark phase transition with the two-phase model.

Junichi Takahashi; Junpei Sugano; Masahiro Ishii; Hiroaki Kouno; Masanobu Yahiro

2014-10-30

52

Somatosensory evoked potentials during standing posture on different support surface.  

PubMed

Somatosensory evoked potentials in response to stimulation of the posterior tibial nerve at the ankle were recorded during standing on stable ground or on unstable support surface (seesaw) or on support surface short in relation to foot length. During standing on the seesaw and on the short support surface a decrease in the amplitude of the early component (N32-P39) was observed. The amplitude of N49-P58 decreased during standing on the short support surface. The amplitude of the later components (N49-P58; P58-N76; N76-P117) decreased during standing on the seesaw in comparison to that during standing on the stable ground and on the short support surface. Thus, the attenuation of the cerebral potential during standing depend on the conditions for maintenance of posture. PMID:1817690

Gavrilenko, T; Gatev, P; Gantchev, G N; Popivanov, D

1991-01-01

53

Different brain potentials evoked at distinct phases of rule learning.  

PubMed

The neural mechanisms of rule learning are of interest to cognitive neuroscientists, but the time course of rule induction and the related brain potential remain unclear. In this study, event-related brain potentials (ERPs) were measured during the distinct phases of rule induction. Participants in two experiments were presented with a series of Arabic numbers and were asked to detect the hidden rules. The ERP results revealed that (a) the rule-discovery trials elicited a larger P3 component than the nondiscovery trials, reflecting the initial identification of the regularity of number series, and (b) when a new instance was incongruent with the previously acquired rule, a larger N2 and enhanced late positive component were elicited, reflecting the process of mismatch detection and the updating of working memory context. PMID:22804836

Li, Fuhong; Cao, Bihua; Gao, Heming; Kuang, Li; Li, Hong

2012-09-01

54

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

55

Effects of different antisecretory drugs on gastric potential difference in the rat: comparison with sucralfate.  

PubMed

The proton pump inhibitors omeprazole and lansoprazole and the histamine H2 receptor antagonists ranitidine and nizatidine were investigated for their effects on gastric transmucosal potential difference (PD) in the rat, in comparison with the gastroprotective compound sucralfate. Omeprazole (1-3 mg kg-1, i.v.) and lansoprazole (1-3 mg kg-1, i.v.) did not modify basal PD, but significantly reduced (by approx. 50-60%) the drop in PD caused by intragastric administration of acetylsalicylic acid (ASA, 60 mg kg-1). Ranitidine (3-100 mg kg-1, i.v.) and nizatidine (10-30 mg kg-1, i.v.) behaved similarly to proton pump inhibitors, being ineffective on basal PD, while significantly reducing the effect of ASA. The antisecretory compounds did not change basal pH values. Sucralfate (0.5-1.5 g kg-1 intragastrically) caused a slight increase (approx. 20%) of basal PD and a dose-dependent reduction of ASA-induced fall in PD, with a maximum effect (65% reduction) comparable to that caused by the antisecretory agents. These results showed that ASA-induced disruption of the mucosal barrier can be reduced to the same extent by various antiulcer drugs, irrespective of their effects on gastric acid secretion. PMID:9990656

Coruzzi, G; Coppelli, G; Frati, P; Bertaccini, G

1998-12-01

56

Potential effects of large linear pipeline construction on soil and vegetation in ecologically fragile regions.  

PubMed

Long-distance pipeline construction results in marked human disturbance of the regional ecosystem and brings into question the safety of pipeline construction with respect to the environment. Thus, the direct environmental impact and proper handling of such large projects have received much attention. The potential environmental effects, however, have not been fully addressed, particularly for large linear pipeline projects, and the threshold of such effects is unclear. In this study, two typical eco-fragile areas in western China, where large linear construction projects have been conducted, were chosen as the case study areas. Soil quality indices (SQI) and vegetation indices (VI), representing the most important potential effects, were used to analyze the scope of the effect of large pipeline construction on the surrounding environment. These two indices in different buffer zones along the pipeline were compared against the background values. The analysis resulted in three main findings. First, pipeline construction continues to influence the nearby eco-environment even after a 4-year recovery period. During this period, the effect on vegetation due to pipeline construction reaches 300 m beyond the working area, and is much larger in distance than the effect on soil, which is mainly confined to within 30 m either side of the pipeline, indicating that vegetation is more sensitive than soil to this type of human disturbance. However, the effect may not reach beyond 500 m from the pipeline. Second, the scope of the effect in terms of distance on vegetation may also be determined by the frequency of disturbance and the intensity of the pipeline construction. The greater the number of pipelines in an area, the higher the construction intensity and the more frequent the disturbance. Frequent disturbance may expand the effect on vegetation on both sides of the pipeline, but not on soil quality. Third, the construction may eliminate the stable, resident plant community. During the recovery period, the plant community in the work area of the pipeline is replaced by some species that are rare or uncommon in the resident plant community because of human disturbance, thereby increasing the plant diversity in the work area. In terms of plant succession, the duration of the recovery period has a direct effect on the composition and structure of the plant community. The findings provide a theoretical basis and scientific foundation for improving the environmental impact assessment (EIA) of oil and gas pipeline construction as it pertains to the desert steppe ecosystem, and provide a reference point for recovery and management of the eco-environment during the pipeline construction period. PMID:25112841

Xiao, Jun; Wang, Ya-Feng; Shi, Peng; Yang, Lei; Chen, Li-Ding

2014-11-01

57

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

58

Reduction of the field-aligned potential drop in the polar cap during large geomagnetic storms  

NASA Astrophysics Data System (ADS)

We have studied photoelectron flows and the inferred field-aligned potential drop in the polar cap during 5 large geomagnetic storms that occurred in the periods when the photoelectron observations in the polar cap were available near the apogee of the FAST satellite (~4000 km) at solar maximum, and the footprint of the satellite paths in the polar cap was under sunlit conditions most of the time. In contrast to the ~20 V potential drop during geomagnetically quiet periods at solar maximum identified by Kitamura et al. [JGR, 2012], the field-aligned potential drop frequently became smaller than ~5 V during the main and early recovery phases of the large geomagnetic storms. Because the potential acts to inhibit photoelectron escape, this result indicates that the corresponding acceleration of ions by the field-aligned potential drop in the polar cap and the lobe region is smaller during the main and early recovery phases of large geomagnetic storms compared to during geomagnetically quiet periods. Under small field-aligned current conditions, the number flux of outflowing ions should be nearly equal to the net escaping electron number flux. Since ions with large flux originating from the cusp/cleft ionosphere convect into the polar cap during geomagnetic storms [e.g., Kitamura et al., JGR, 2010], the net escaping electron number flux should increase to balance the enhanced ion outflows. The magnitude of the field-aligned potential drop would be reduced to let a larger fraction of photoelectrons escape.

Kitamura, N.; Seki, K.; Nishimura, Y.; Hori, T.; Terada, N.; Ono, T.; Strangeway, R. J.

2013-12-01

59

Large Autosomal Copy-Number Differences within Unselected Monozygotic Twin Pairs are Rare.  

PubMed

Monozygotic (MZ) twins form an important system for the study of biological plasticity in humans. While MZ twins are generally considered to be genetically identical, a number of studies have emerged that have demonstrated copy-number differences within a twin pair, particularly in those discordant for disease. The rate of autosomal copy-number variation (CNV) discordance within MZ twin pairs was investigated using a population sample of 376 twin pairs genotyped on Illumina Human610-Quad arrays. After CNV calling using both QuantiSNP and PennCNV followed by manual annotation, only a single CNV difference was observed within the MZ twin pairs, being a 130 KB duplication of chromosome 5. Five other potential discordant CNV were called by the software, but excluded based on manual annotation of the regions. It is concluded that large CNV discordance is rare within MZ twin pairs, indicating that any CNV difference found within phenotypically discordant MZ twin pairs has a high probability of containing the causal gene(s) involved. PMID:25578400

McRae, Allan F; Visscher, Peter M; Montgomery, Grant W; Martin, Nicholas G

2015-02-01

60

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

61

Characterization of Different Functionalized Lipidic Nanocapsules as Potential Drug Carriers  

PubMed Central

Lipid nanocapsules (LNC) based on a core-shell structure consisting of an oil-filled core with a surrounding polymer layer are known to be promising vehicles for the delivery of hydrophobic drugs in the new therapeutic strategies in anti-cancer treatments. The present work has been designed as basic research about different LNC systems. We have synthesized—and physico-chemically characterized—three different LNC systems in which the core was constituted by olive oil and the shell by different phospholipids (phosphatidyl-serine or lecithin) and other biocompatible molecules such as Pluronic® F68 or chitosan. It is notable that the olive-oil-phosphatidyl-serine LCN is a novel formulation presented in this work and was designed to generate an enriched carboxylic surface. This carboxylic layer is meant to link specific antibodies, which could facilitate the specific nanocapsule uptake by cancer cells. This is why nanoparticles with phosphatidyl-serine in their shell have also been used in this work to form immuno-nanocapsules containing a polyclonal IgG against a model antigen (C-reactive protein) covalently bounded by means of a simple and reproducible carbodiimide method. An immunological study was made to verify that these IgG-LNC complexes showed the expected specific immune response. Finally, a preliminary in vitro study was performed by culturing a breast-carcinoma cell line (MCF-7) with Nile-Red-loaded LNC. We found that these cancer cells take up the fluorescent Nile- Red molecule in a process dependent on the surface properties of the nanocarriers. PMID:22408461

Sánchez-Moreno, Paola; Ortega-Vinuesa, Juan Luis; Martín-Rodríguez, Antonio; Boulaiz, Houría; Marchal-Corrales, Juan Antonio; Peula-García, José Manuel

2012-01-01

62

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

PubMed

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 showed maximum biomass production, growth rate (mg day(-1)), mean cocoon numbers, and reproduction rate (cocoon worm(-1)) in VLL (vegetable waste+leaf litter) as compared to other substrate materials. There was a consistent trend for earthworms' growth and reproduction rate, related to initial N-content of the substrate (P<0.05), but there was no clear effect of C:N ratio of the composted material on earthworm cocoon numbers and weight gain. Earthworm showed minimum total population mortality in VLL and maximum in HHCD (household waste+cow dung), after 150 days of experimentation. The increased level of plant metabolites in end product (vermicompost) and growth patterns of P. sansibaricus in different organic waste resources demonstrated the candidature of this species for wastes recycle operations at low-input basis. PMID:16828549

Suthar, Surendra

2007-04-01

63

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

64

Role of Structure and Entropy in Determining Differences in Dynamics for Glass Formers with Different Interaction Potentials.  

PubMed

We present a study of two model liquids with different interaction potentials, exhibiting similar structure but significantly different dynamics at low temperatures. By evaluating the configurational entropy, we show that the differences in the dynamics of these systems can be understood in terms of their thermodynamic differences. Analyzing their structure, we demonstrate that differences in pair correlation functions between the two systems, through their contribution to the entropy, dominate the differences in their dynamics, and indeed overestimate the differences. Including the contribution of higher order structural correlations to the entropy leads to smaller estimates for the relaxation times, as well as smaller differences between the two studied systems. PMID:25494076

Banerjee, Atreyee; Sengupta, Shiladitya; Sastry, Srikanth; Bhattacharyya, Sarika Maitra

2014-11-28

65

Eulerian Spectral/Finite Difference Method for Large Deformation Modelling of  

E-print Network

Eulerian Spectral/Finite Difference Method for Large Deformation Modelling of Visco to the solving of visco- elasto-plastic rheological equations. Here a spectral/finite-difference method is de the governing equations by an eule- rian finite-difference/spectral method [4]. 2 Mathematical model For many

Kaus, Boris

66

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

Microsoft Academic Search

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 where

Rebecca L. Rowe; Gail Taylor

2009-01-01

67

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...

68

innovati nNREL Confirms Large Potential for Grid Integration of Wind, Solar Power  

E-print Network

innovati nNREL Confirms Large Potential for Grid Integration of Wind, Solar Power To fully harvest the nation's bountiful wind and solar resources, it is critical to know how much electrical power from penetrations of wind power. NREL is a national laboratory of the U.S. Department of Energy, Office of Energy

69

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

70

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.

71

Predicting Snow Velocity in Large Chute Flows Under Different Environmental Conditions  

E-print Network

Predicting Snow Velocity in Large Chute Flows Under Different Environmental Conditions Jonathan Rougier Department of Mathematics University of Bristol, UK Martin Kern Swiss Federal Institute for Snow, and expert judge- ments are combined to make predictions of snow velocity in large chute experiments

Oakley, Jeremy

72

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. PMID:21059938

Kaser, Georg; Großhauser, Martin; Marzeion, Ben

2010-01-01

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

Small changes result in large differences: discovery of (-)-incrustoporin derivatives as novel antiviral and antifungal agents.  

PubMed

On the basis of the structure of natural product (-)-incrustoporin (1), a series of lactone compounds 4a-i and 5a-i were designed and synthesized from nitroolefin. The antiviral and antifungal activities of these compounds were evaluated in vitro and in vivo. The small changes between 4 and 5 at the 3,4-position result in large differences in bioactivities. Compounds 4 exhibited significantly higher antiviral activity against tobacco mosaic virus (TMV) than dehydro compounds 5. However, the antifungal activity of 4 is relatively lower than that of 5. Compounds 4a, 4c, and 4i with excellent in vivo anti-TMV activity emerged as new antiviral lead compounds. Compounds 5d-g showed superiority over the commercial fungicides chlorothalonil and carbendazim against Cercospora arachidicola Hor at 50 mg kg(-1). The present study provides fundamental support for the development and optimization of (-)-incrustoporin derivatives as potential inhibitors of plant virus and pathogenic fungi. PMID:25116598

Lu, Aidang; Wang, Jinjin; Liu, Tengjiao; Han, Jian; Li, Yinhui; Su, Min; Chen, Jianxin; Zhang, Hui; Wang, Lizhong; Wang, Qingmin

2014-09-01

75

Milky Way potentials in cold dark matter and MOdified Newtonian Dynamics. Is the Large Magellanic Cloud on a bound orbit?  

NASA Astrophysics Data System (ADS)

We compute the Milky Way potential in different cold dark matter (CDM) based models, and compare these with the MOdified Newtonian Dynamics (MOND) framework. We calculate the axial ratio of the potential in various models, and find that isopotentials are less spherical in MOND than in CDM potentials. As an application of these models, we predict the escape velocity as a function of the position in the Galaxy. This could be useful in comparing with future data from planned or already-underway kinematic surveys (RAVE, SDSS, SEGUE, SIM, Gaia or the hypervelocity stars survey). In addition, the predicted escape velocity is compared with the recently measured high proper motion velocity of the Large Magellanic Cloud (LMC). To bind the LMC to the Galaxy in a MOND model, while still being compatible with the RAVE-measured local escape speed at the Sun's position, we show that an external field modulus of less than 0.03a0 is needed.

Wu, Xufen; Famaey, Benoit; Gentile, Gianfranco; Perets, Hagai; Zhao, Hongsheng

2008-06-01

76

Characterization and potential functional significance of human-chimpanzee large INDEL variation  

PubMed Central

Background Although humans and chimpanzees have accumulated significant differences in a number of phenotypic traits since diverging from a common ancestor about six million years ago, their genomes are more than 98.5% identical at protein-coding loci. This modest degree of nucleotide divergence is not sufficient to explain the extensive phenotypic differences between the two species. It has been hypothesized that the genetic basis of the phenotypic differences lies at the level of gene regulation and is associated with the extensive insertion and deletion (INDEL) variation between the two species. To test the hypothesis that large INDELs (80 to 12,000 bp) may have contributed significantly to differences in gene regulation between the two species, we categorized human-chimpanzee INDEL variation mapping in or around genes and determined whether this variation is significantly correlated with previously determined differences in gene expression. Results Extensive, large INDEL variation exists between the human and chimpanzee genomes. This variation is primarily attributable to retrotransposon insertions within the human lineage. There is a significant correlation between differences in gene expression and large human-chimpanzee INDEL variation mapping in genes or in proximity to them. Conclusions The results presented herein are consistent with the hypothesis that large INDELs, particularly those associated with retrotransposons, have played a significant role in human-chimpanzee regulatory evolution. PMID:22024410

2011-01-01

77

Consistency and influence on performance of behavioural differences in Large White and Landrace purebred pigs  

Microsoft Academic Search

According to the theory of behavioural strategies, individual animals show clear consistency when they have to adapt to environmental changes and challenges: their responses are predictable in different situations and throughout time. The main objective of this research was to evaluate behavioural differences between pigs of Large White (LW) and Landrace (LD) breeds. A total of 119 male pigs were

Xavier Fernàndez de Sevilla; Joaquim Casellas; Joan Tibau; Emma Fàbrega

2009-01-01

78

Gender Differences in Large-Scale Math Assessments: PISA Trend 2000 and 2003  

ERIC Educational Resources Information Center

Many efforts have been made to determine and explain differential gender performance on large-scale mathematics assessments. A well-agreed-on conclusion is that gender differences are contextualized and vary across math domains. This study investigated the pattern of gender differences by item domain (e.g., Space and Shape, Quantity) and item type…

Liu, Ou Lydia; Wilson, Mark

2009-01-01

79

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

80

Cosmological constraints from Gauss-Bonnet braneworld with large-field potentials  

E-print Network

We calculate the spectral index and tensor-to-scalar ratio for patch inflation defined by $H^2\\approx \\beta^2_q V^q$ and $\\dot{\\phi}\\approx -V'/3H$, using the slow-roll expansion. The patch cosmology arisen from the Gauss-Bonnet braneworld consists of Gauss-Bonnet (GB), Randall-Sundrum (RS), and 4D general relativistic (GR) cosmological models. In this work, we choose large-field potentials of $V=V_0\\phi^p$ to compare with the observational data. Since second-order corrections are rather small in the slow-roll limit, the leading-order calculation is sufficient to compare with the data. Finally, we show that it is easier to discriminate between quadratic potential and quartic potential in the GB cosmological model rather than the GR or RS cosmological models.

Kyong Hee Kim; Yun Soo Myung

2004-08-16

81

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

82

Gender Differences in Large-Scale Math Assessments: PISA Trend 2000 and 2003  

Microsoft Academic Search

Many efforts have been made to determine and explain differential gender performance on large-scale mathematics assessments. A well-agreed-on conclusion is that gender differences are contextualized and vary across math domains. This study investigated the pattern of gender differences by item domain (e.g., Space and Shape, Quantity) and item type (e.g., multiple-choice items, open constructed-response items). The U.S. portion of the

Ou Lydia Liu; Mark Wilson

2009-01-01

83

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

84

Coping Resources and Self-Esteem Differences between Students Selecting Large and Small Colleges.  

ERIC Educational Resources Information Center

Compares responses on self-report inventories of coping resources and self-esteem between samples of students attending a small private college and a large state university. Differences were found in physical and spiritual/philosophical types of coping resources as well as social self-esteem. Includes suggestions for further research in this area…

Rawson, Harve E.; Palmer, David W.; Henderson, Janet

1999-01-01

85

Large-rock avalanche deposits, eastern Basin and Range, Utah: Emplacement, diagenesis, and economic potential  

SciTech Connect

Large-rock avalanche deposits are a common component of the basin fill within the extensional tectonic terrain of the Basin and Range; these deposits recently have been interpreted to host oil and gas within the Railroad Valley area of eastern Nevada. Large blocks of brecciated bedrock are a primary component of these avalanche deposits and are potentially excellent oil and gas reservoirs. Our work provides further insight into the emplacement and economic potential of these deposits. Exposed large-rock avalanche deposits of the Miocene Oak City Formation on the western margin of the Canyon Range, Utah, contain coherent breccia blocks up to 3.5 km long, 1 km wide, and 200 m thick. These deposits were derived from the near-vertical dipping bed rock of the adjacent Canyon Range and now are exposed as much as 5.5 km from the range front within the Sevier Desert basin. Emplacement was relatively rapid, as indicated by three well-developed breccia facies within the carbonate breccia blocks. Stratigraphically, from the base the facies include (1) matrix-rich breccia, (2) jigsaw breccia, and (3) crackle breccia. The deposits were cut and segmented by a series of syn-depositional normal faults that developed during late Miocene and post-Miocene extension. Primary porosity was reduced by cement soon after burial. Cathodoluminescence cement patterns indicate that initially the basinward breccia blocks were more deeply buried relative to the water table than the breccia blocks proximal to the Canyon Range. After initial cementation, the basinward blocks were uplifted relative to the water table. Secondary porosity approaches 8% in the carbonate blocks and is greater than 14% within the jigsaw breccia. The size and porosity of these breccia blocks indicate their potential as reservoir targets.

Morris, T.H.; Hebertson, G.F. [Brigham Young Univ., Provo, Utah (United States)

1996-07-01

86

Large anti-HER2/neu liposomes for potential targeted intraperitoneal therapy of micrometastatic cancer  

PubMed Central

Effective targeting and killing of intraperitoneally disseminated micrometastases remains a challenge. Objective/Methods In this work, we evaluated the potential of antibody-labeled PEGylated large liposomes as vehicles for direct intraperitoneal (i.p.) drug delivery with the aim to enhance the tumor-to-normal organ ratio and to improve the bioexposure of cancer cells to the delivered therapeutics while shifting the toxicities toward the spleen. These targeted liposomes are designed to combine: (1) specific targeting to and internalization by cancer cells mediated by liposome-conjugated tumor-specific antibodies, (2) slow clearance from the peritoneal cavity, and (3) shift of normal organ toxicities from the liver to the spleen due to their relatively large size. Results Conjugation of anti-HER2/neu antibodies to the surface of large (approximately 600 nm in diameter) PEGylated liposomes results in fast, specific binding of targeted liposomes to cancer cells in vitro, followed by considerable cellular internalization. In vivo, after i.p. administration, these liposomes exhibit fast, specific binding to i.p. cancerous tumors. Large liposomes are slowly cleared from the peritoneal cavity, and they exhibit increased uptake by the spleen relative to the liver, while targeted large liposomes demonstrate specific tumor uptake at early times. Although tissue and tumor uptake are greater for cationic liposomes, the tumor-to-liver and spleen-to-liver ratios are similar for both membrane compositions, suggesting a primary role for the liposome’s size, compared to the liposome’s surface charge. Conclusions The findings of this study suggest that large targeted liposomes administered i.p. could be a potent drug-delivery strategy for locoregional therapy of i.p. micrometastatic tumors. PMID:20070139

Sofou, Stavroula; Enmon, Richard; Palm, Stig; Kappel, Barry; Zanzonico, Pat; McDevitt, Michael R.; Scheinberg, David A.; Sgouros, George

2011-01-01

87

Electrolyte and Haemogram changes post large volume liposuction comparing two different tumescent solutions  

PubMed Central

Background: The most common definitions of large volume liposuction refer to total 5 l volume aspiration during a single procedure (fat plus wetting solution). Profound haemodynamic and metabolic alterations can accompany large volume liposuction. Due to paucity of literature on the effect of different tumescent solutions on the electrolyte balance and haematological changes during large volume liposuction, we carried out this study using two different wetting solutions to study the same. Materials and Methods: Total 30 patients presenting with varying degrees of localized lipodystrophy in different body regions were enrolled for the study. Prospective randomized controlled trial was conducted by Department of Plastic and Cosmetic Surgery, Sir Ganga Ram Hospital, New Delhi from January 2011 to June 2012. Patients were randomized into two groups of 15 patients each by using computer generated random numbers. Tumescent formula used for Group A (normal saline [NS]) was our modification of Klein's Formula and Tumescent formula used for Group B (ringer lactate [RL]) was our modification of Hunstadt's formula. Serum electrolytes and hematocrit levels were done at preinduction, immediate postoperative period and postoperative day 1. Result: Statistical analysis was performed using SPSS software version 15.0. Which showed statistically significant electrolytes and hematocrit changes occur during large volume liposuction. Conclusion: Statistically significant electrolytes and hematocrit changes occur during large volume liposuction and patients should be kept under observation of anaesthesist for at least 24 h. Patients require strict monitoring of vital parameters and usually Intensive Care Unit is not required. There was no statistical difference in the electrolyte changes using NS or RL as tumescent solution and both solutions were found safe for large volume liposuction.

Vivek, Kumar; Amiti, Shah; Shivshankar, Saha; Lalit, Choudhary

2014-01-01

88

Which water potential? Differences between isopiestic thermocouple psychrometer measurements of intact and excised plant materials  

Microsoft Academic Search

Water potentials of leaves from well-watered plants were measured. There were species-specific differences in both the total\\u000a and the osmotic potentials of pea (Pisum sativum), tradescantia (Tradescantia versicolor), rose (Rosa hybrida), bitter lemon (Citrus aurantium) and olive (Olea europaea). With tradescantia the potential measured after the destruction of turgor by freezing was less negative than before, a result\\u000a which suggests

Man Singh Manohar

1971-01-01

89

Analysis of the Potential for a Heat Island Effect in Large Solar Vasilis Fthenakis1,2  

E-print Network

Analysis of the Potential for a Heat Island Effect in Large Solar Farms Vasilis Fthenakis1 flow fields induced by large solar PV farms to answer questions pertaining to potential impacts simulations of a 1 MW section of a solar farm in North America and compared the results with recorded wind

90

Hamilton's principle: Why is the integrated difference of the kinetic and potential energy minimized?  

Microsoft Academic Search

Why is the integrated difference of the kinetic and potential energies the quantity to be minimized in Hamilton's principle? I use simple arguments to convert the problem of finding the path of a particle connecting two points to that of finding the minimum potential energy of a string. The mapping implies that the configuration of a nonstretchable string of variable

Alberto G. Rojo

2005-01-01

91

Comparison of water potentials measured by in situ psychrometry and pressure chamber in morphologically different species.  

PubMed

Leaf water potentials measured by in situ psychrometry were compared with leaf water potentials measured by the pressure chamber technique at various values of water potential in Helianthus annuus, Helianthus nuttallii, Vigna unguiculata, Nerium oleander, Pistacia vera, and Corylus avellana. In V. unguiculata, the leaf water potentials measured by the in situ psychrometer oscillated at the same periodicity as, and proportional to, the leaf conductance. In all species, potentials measured by in situ psychrometers operating in the psychrometric mode were linearly correlated with potentials measured with the pressure chamber. However, the in situ psychrometers underestimated the leaf water potential in the two Helianthus species at low water potentials and overestimated the water potential in P. vera, N. oleander, and C. avellana. The underestimation in the two Helianthus species at low water potentials resulted from differences in water potential across the leaf. The overestimation in P. vera, N. oleander, and C. avellana was considered to arise from low epidermal conductances in these species even after abrasion of the cuticle. Pressure-volume studies with Lycopersicon esculentum showed that less water was expressed from distal than proximal leaflets when the whole leaf was slowly pressurized. The implication of this for water relations characteristics obtained by pressure-volume techniques is discussed. We conclude that in situ psychrometers are suitable for following dynamic changes in leaf water potential, but should be used with caution on leaves with low epidermal conductances. PMID:16663415

Turner, N C; Spurway, R A; Schulze, E D

1984-02-01

92

Comparison of different hand-drying methods: the potential for airborne microbe dispersal and contamination.  

PubMed

Efficient washing and drying of hands is important in prevention of the transfer of micro-organisms. However, knowledge surrounding the potential for microbial contamination according to hand-drying methods is limited. This study assessed the potential for airborne microbe dispersal during hand drying by four methods (paper towels, roller towel, warm air and jet air dryer) using three different models. The jet air dryer dispersed liquid from users' hands further and over a greater range (up to 1.5m) than the other drying methods (up to 0.75m), demonstrating the differing potential risks for airborne microbe dissemination, particularly if handwashing is suboptimal. PMID:25586988

Best, E L; Redway, K

2015-03-01

93

Automated system for identifying potential dosage problems at a large university hospital.  

PubMed

A hospital's experience with an automated system for screening drug orders for potential dosage problems is described. DoseChecker was developed by the hospital pharmacy department in collaboration with a local university. Pharmacy, laboratory, and patient demographic data are transferred nightly from the hospital's mainframe system to a database server; DoseChecker uses these data and user-defined rules to (1) identify patients receiving any of 35 targeted medications, (2) evaluate the appropriateness of current dosages, and (3) generate alerts for patients potentially needing dosage adjustments. The alert reports are distributed to satellite pharmacists, who evaluate each patient's condition and make recommendations to physicians as needed. One of the system's primary purposes is to calculate creatinine clearance and verify that dosages are properly adjusted for renal function. Between May and October 1995, the system electronically screened 28,528 drug orders and detected potential dosage problems in 2859 (10%). The system recommended a lower daily dose in 1992 cases (70%) and a higher daily dose in 867 (30%). Pharmacists contacted physicians concerning 1163 (41%) of the 2859 alerts; in 868 cases (75%), the physicians agreed to adjust the dosage. The most common dosage problem identified was failure to adjust dosages on the basis of declining renal function. An automated system provided an efficient method of identifying inappropriate dosages at a large university hospital. PMID:9066863

McMullin, S T; Reichley, R M; Kahn, M G; Dunagan, W C; Bailey, T C

1997-03-01

94

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

95

Analytical solitary-wave solutions of the generalized nonautonomous cubic-quintic nonlinear Schroedinger equation with different external potentials  

SciTech Connect

A large family of analytical solitary wave solutions to the generalized nonautonomous cubic-quintic nonlinear Schroedinger equation with time- and space-dependent distributed coefficients and external potentials are obtained by using a similarity transformation technique. We use the cubic nonlinearity as an independent parameter function, where a simple procedure is established to obtain different classes of potentials and solutions. The solutions exist under certain conditions and impose constraints on the coefficients depicting dispersion, cubic and quintic nonlinearities, and gain (or loss). We investigate the space-quadratic potential, optical lattice potential, flying bird potential, and potential barrier (well). Some interesting periodic solitary wave solutions corresponding to these potentials are then studied. Also, properties of a few solutions and physical applications of interest to the field are discussed. Finally, the stability of the solitary wave solutions under slight disturbance of the constraint conditions and initial perturbation of white noise is discussed numerically; the results reveal that the solitary waves can propagate in a stable way under slight disturbance of the constraint conditions and the initial perturbation of white noise.

He Junrong; Li Huamei [Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004 (China)

2011-06-15

96

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

97

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

98

Temporal-spatial changes in Sonic Hedgehog expression and signaling reveal different potentials of ventral  

E-print Network

Temporal-spatial changes in Sonic Hedgehog expression and signaling reveal different potentials ARTICLE Open Access Temporal-spatial changes in Sonic Hedgehog expression and signaling reveal different mesencephalic precursors that express Sonic Hedgehog (Shh). However, Shh expression, which is initially confined

Paris-Sud XI, Université de

99

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

100

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

101

Cancer stem cells display extremely large evolvability: alternating plastic and rigid networks as a potential mechanism  

E-print Network

Cancer is increasingly perceived as a systems-level, network phenomenon. The major trend of malignant transformation can be described as a two-phase process, where an initial increase of network plasticity is followed by a decrease of plasticity at late stages of tumor development. The fluctuating intensity of stress factors, like hypoxia, inflammation and the either cooperative or hostile interactions of tumor inter-cellular networks, all increase the adaptation potential of cancer cells. This may lead to the bypass of cellular senescence, and to the development of cancer stem cells. We propose that the central tenet of cancer stem cell definition lies exactly in the indefinability of cancer stem cells. Actual properties of cancer stem cells depend on the individual "stress-history" of the given tumor. Cancer stem cells are characterized by an extremely large evolvability (i.e. a capacity to generate heritable phenotypic variation), which corresponds well with the defining hallmarks of cancer stem cells: the...

Csermely, Peter; Korcsmaros, Tamas; Modos, Dezso; Perez-Lopez, Aron R; Szalay, Kristof; Veres, Daniel V; Lenti, Katalin; Wu, Ling-Yun; Zhang, Xiang-Sun

2013-01-01

102

Detection of large color variation in the potentially hazardous asteroid (297274) 1996 SK  

NASA Astrophysics Data System (ADS)

Low-inclination near-earth asteroid (NEA) (297274) 1996 SK, which is also classified as a potentially hazardous asteroid, has a highly eccentric orbit. It was studied by multi-wavelength photometry within the framework of an NEA color survey at Lulin Observatory. Here, we report the finding of large color variation across the surface of (297274) 1996 SK within one asteroidal rotation period of 4.656 ± 0.122 hours and classify it as an S-type asteroid according to its average colors of B — V = 0.767 ± 0.033, V — R = 0.482 ± 0.021, V — I = 0.801 ± 0.025 and the corresponding relative reflectance spectrum. These results might be indicative of differential space weathering or compositional inhomogeneity in the surface materials.

Lin, Chien-Hsien; Ip, Wing-Huen; Lin, Zhong-Yi; Yoshida, Fumi; Cheng, Yu-Chi

2014-03-01

103

SOIL-ROOT INTERFACE WATER POTENTIAL IN PrunusXcistena GROWN IN DIFFERENT ARTIFICIAL MIXES  

Microsoft Academic Search

Xu H. L., CARON J., BERNIER P. Y., GAUTHIER L. and GOSSELIN A. Soil-root interface water potential in Prunusxcistena grown in different artificial mixes. BIOTRONICS 24, 35-43, 1995. The water potential at soil-root interface (Ys,), indicates soil water availability at the point of contact between the root and the soil. It is important in the pathway of water flow from

H. L. Xu; P. Y. BERNIER; L. GAUTHIER; A. GOSSELIN

104

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

105

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

106

Hamilton’s principle: Why is the integrated difference of the kinetic and potential energy minimized?  

Microsoft Academic Search

I present an intuitive answer to an often asked question: why is the\\u000aintegrated difference K-U between the kinetic and potential energy the quantity\\u000ato be minimized in Hamilton's principle?\\u000a Using elementary arguments, I map the problem of finding the path of a moving\\u000aparticle connecting two points to that of finding the minimum potential energy\\u000aof a static string.

Alberto G. Rojo

2005-01-01

107

Relevant distance between two different instances of the same potential energy in protein folding  

E-print Network

In the context of complex systems and, particularly, of protein folding, a physically meaningful distance is defined which allows to make useful statistical statements about the way in which energy differences are modified when two different instances of the same potential-energy function are used. When the two instances arise from the fact that different algorithms or different approximations are used, the distance herein defined may be used to evaluate the relative accuracy of the two methods. When the difference is due to a change in the free parameters of which the potential depends on, the distance can be used to quantify, in each region of parameter space, the robustness of the modeling to such a change and this, in turn, may be used to assess the significance of a parameters' fit. Both cases are illustrated with a practical example: the study of the Poisson-based solvation energy in the Trp-Cage protein (PDB code 1L2Y).

Jose Luis Alonso; Pablo Echenique

2005-04-21

108

Surface tension, surface energy, and chemical potential due to their difference.  

PubMed

It is well-known that surface tension and surface energy are distinct quantities for solids. Each can be regarded as a thermodynamic property related first by Shuttleworth. Mullins and others have suggested that the difference between surface tension and surface energy cannot be sustained and that the two will approach each other over time. In this work we show that in a single-component system where changes in elastic energy can be neglected, the chemical potential difference between the surface and bulk is proportional to the difference between surface tension and surface energy. By further assuming that mass transfer is driven by this chemical potential difference, we establish a model for the kinetics by which mass transfer removes the difference between surface tension and surface energy. PMID:23926928

Hui, C-Y; Jagota, A

2013-09-10

109

Large climate-moderating envelopes for enclosed structures: a preliminary evaluation of energy conservation potential  

SciTech Connect

An investigation was made of the basic impacts of putting a large secondary enclosure around a number of functions and thereby creating a Large Climate Moderating Envelope (LCME). This study is a preliminary estimate of the energy conservation benefits of an LCME. A hypothetical LMCE design was chosen and a coupled fluid dynamic and energy transport analysis was performed to estimate the energy conservation potential of this design. The heat transfer models included insolation, outside air temperature and wind, thermal radiation exchange with the sky, and between the fabric and ground and thermal storage in the earth mass beneath the LCME. The energy transported within the fluid by the buoyancy driven circulation was modeled as an incompressible fluid utilizing the Boussinesq approximation. The climatic conditions were assumed to vary in smooth repeating daily cycles. The numerical simulation of climatic variation was continued until the results within the LCME achieved a repeating daily cycle. The results for selected seasonally characteristic days were utilized to estimate the annual energy consumption of structures within an LCME relative to similar structures exposed to the exterior environment. The relative annual energy savings for summer-dominated climates was estimated to be approx. 70%. The energy savings for a winter-dominated climate LCME were estimated to be somewhat smaller but the LCME concept could offer significant benefits for agricultural applications for this type of climate.

Wendt, R.L.; Giles, G.E.; Park, J.E.

1981-12-01

110

FOXP1 potentiates Wnt/?-catenin signaling in diffuse large B cell lymphoma.  

PubMed

The transcription factor FOXP1 (forkhead box protein P1) is a master regulator of stem and progenitor cell biology. In diffuse large B cell lymphoma (DLBCL), copy number amplifications and chromosomal translocations result in overexpression of FOXP1. Increased abundance of FOXP1 in DLBCL is a predictor of poor prognosis and resistance to therapy. We developed a genome-wide, mass spectrometry-coupled, gain-of-function genetic screen, which revealed that FOXP1 potentiates ?-catenin-dependent, Wnt-dependent gene expression. Gain- and loss-of-function studies in cell models and zebrafish confirmed that FOXP1 was a general and conserved enhancer of Wnt signaling. In a Wnt-dependent fashion, FOXP1 formed a complex with ?-catenin, TCF7L2 (transcription factor 7-like 2), and the acetyltransferase CBP [CREB (adenosine 3',5'-monophosphate response element-binding protein)-binding protein], and this complex bound the promoters of Wnt target genes. FOXP1 promoted the acetylation of ?-catenin by CBP, and acetylation was required for FOXP1-mediated potentiation of ?-catenin-dependent transcription. In DLBCL, we found that FOXP1 promoted sensitivity to Wnt pathway inhibitors, and knockdown of FOXP1 or blocking ?-catenin transcriptional activity slowed xenograft tumor growth. These data connect excessive FOXP1 with ?-catenin-dependent signal transduction and provide a molecular rationale for Wnt-directed therapy in DLBCL. PMID:25650440

Walker, Matthew P; Stopford, Charles M; Cederlund, Maria; Fang, Fang; Jahn, Christopher; Rabinowitz, Alex D; Goldfarb, Dennis; Graham, David M; Yan, Feng; Deal, Allison M; Fedoriw, Yuri; Richards, Kristy L; Davis, Ian J; Weidinger, Gilbert; Damania, Blossom; Major, Michael B

2015-02-01

111

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

112

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. PMID:24721710

2014-01-01

113

Multiple mechanisms involved in the large-spectrum therapeutic potential of cannabidiol in psychiatric disorders  

PubMed Central

Cannabidiol (CBD) is a major phytocannabinoid present in the Cannabis sativa plant. It lacks the psychotomimetic and other psychotropic effects that the main plant compound ?9-tetrahydrocannabinol (THC) being able, on the contrary, to antagonize these effects. This property, together with its safety profile, was an initial stimulus for the investigation of CBD pharmacological properties. It is now clear that CBD has therapeutic potential over a wide range of non-psychiatric and psychiatric disorders such as anxiety, depression and psychosis. Although the pharmacological effects of CBD in different biological systems have been extensively investigated by in vitro studies, the mechanisms responsible for its therapeutic potential are still not clear. Here, we review recent in vivo studies indicating that these mechanisms are not unitary but rather depend on the behavioural response being measured. Acute anxiolytic and antidepressant-like effects seem to rely mainly on facilitation of 5-HT1A-mediated neurotransmission in key brain areas related to defensive responses, including the dorsal periaqueductal grey, bed nucleus of the stria terminalis and medial prefrontal cortex. Other effects, such as anti-compulsive, increased extinction and impaired reconsolidation of aversive memories, and facilitation of adult hippocampal neurogenesis could depend on potentiation of anandamide-mediated neurotransmission. Finally, activation of TRPV1 channels may help us to explain the antipsychotic effect and the bell-shaped dose-response curves commonly observed with CBD. Considering its safety profile and wide range of therapeutic potential, however, further studies are needed to investigate the involvement of other possible mechanisms (e.g. inhibition of adenosine uptake, inverse agonism at CB2 receptor, CB1 receptor antagonism, GPR55 antagonism, PPAR? receptors agonism, intracellular (Ca2+) increase, etc.), on CBD behavioural effects. PMID:23108553

Campos, Alline Cristina; Moreira, Fabricio Araújo; Gomes, Felipe Villela; Del Bel, Elaine Aparecida; Guimarães, Francisco Silveira

2012-01-01

114

Multiple mechanisms involved in the large-spectrum therapeutic potential of cannabidiol in psychiatric disorders.  

PubMed

Cannabidiol (CBD) is a major phytocannabinoid present in the Cannabis sativa plant. It lacks the psychotomimetic and other psychotropic effects that the main plant compound ?(9)-tetrahydrocannabinol (THC) being able, on the contrary, to antagonize these effects. This property, together with its safety profile, was an initial stimulus for the investigation of CBD pharmacological properties. It is now clear that CBD has therapeutic potential over a wide range of non-psychiatric and psychiatric disorders such as anxiety, depression and psychosis. Although the pharmacological effects of CBD in different biological systems have been extensively investigated by in vitro studies, the mechanisms responsible for its therapeutic potential are still not clear. Here, we review recent in vivo studies indicating that these mechanisms are not unitary but rather depend on the behavioural response being measured. Acute anxiolytic and antidepressant-like effects seem to rely mainly on facilitation of 5-HT1A-mediated neurotransmission in key brain areas related to defensive responses, including the dorsal periaqueductal grey, bed nucleus of the stria terminalis and medial prefrontal cortex. Other effects, such as anti-compulsive, increased extinction and impaired reconsolidation of aversive memories, and facilitation of adult hippocampal neurogenesis could depend on potentiation of anandamide-mediated neurotransmission. Finally, activation of TRPV1 channels may help us to explain the antipsychotic effect and the bell-shaped dose-response curves commonly observed with CBD. Considering its safety profile and wide range of therapeutic potential, however, further studies are needed to investigate the involvement of other possible mechanisms (e.g. inhibition of adenosine uptake, inverse agonism at CB2 receptor, CB1 receptor antagonism, GPR55 antagonism, PPAR? receptors agonism, intracellular (Ca(2+)) increase, etc.), on CBD behavioural effects. PMID:23108553

Campos, Alline Cristina; Moreira, Fabricio Araújo; Gomes, Felipe Villela; Del Bel, Elaine Aparecida; Guimarães, Francisco Silveira

2012-12-01

115

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. PMID:24363710

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

2010-01-01

116

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

117

How to Help Children with Learning Differences Reach Their Full Potential  

ERIC Educational Resources Information Center

This article is the third part of a 10-part series that explores Attention Deficit Hyperactivity Disorder (ADHD). It offers and discusses tips on how to help children with learning differences reach their full potential. These include: (1) start with good nutrition; (2) be sure your child is exercising; (3) make sure your child is getting enough…

Lavoie, Theresa

2008-01-01

118

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

119

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

120

Artificial neural networks approach for zeta potential of Montmorillonite in the presence of different cations  

NASA Astrophysics Data System (ADS)

In this study, the zeta potential of montmorillonite in the presence of different chemical solutions was modeled by means of artificial neural networks (ANNs). Zeta potential of the montmorillonite was measured in the presence of salt cations, Na+, Li+ and Ca2+ and metals Zn2+, Pb2+, Cu2+, and Al3+ at different pH values, and observed values pointed to a different behavior for this mineral in the presence of salt and heavy metal cations. Artificial neural networks were successfully developed for the prediction of the zeta potential of montmorillonite in the presence of salt and heavy metal cations at different pH values and ionic strengths. Resulting zeta potential of montmorillonite shows different behavior in the presence of salt and heavy metal cations, and two ANN models were developed in order to be compared with experimental results. The ANNs results were found to be close to experimentally measured zeta potential values. The performance indices such as coefficient of determination, root mean square error, mean absolute error, and variance account for were used to control the performance of the prediction capacity of the models developed in this study. These indices obtained make it clear that the predictive models constructed are quite powerful. The constructed ANN models exhibited a high performance according to the performance indices. This performance has also shown that the ANNs seem to be a useful tool to minimize the uncertainties encountered during the soil engineering projects. For this reason, the use of ANNs may provide new approaches and methodologies.

Yukselen, Yeliz; Erzin, Yusuf

2008-05-01

121

Communication between multiple large earthquakes at different spatial scales across and beyond the Tibetan Plateau  

NASA Astrophysics Data System (ADS)

While seismicity is common on the Tibetan Plateau, the year 2008 was unusual in that several large dip-slip earthquakes occurred widely distributed across the Plateau. Four large primary normal faults (Mw 6.3 to 7.1) ruptured in different parts of the Plateau between January and October 2008, and the devastating Mw 7.9 thrust faulting Wenchuan earthquake occurred at the steep eastern margin in May. Another thrust event (Mw 6.3) occurred in the Qaidam Basin in November 2008, followed nine months later by a similar, shallower event at the same location. The extensional moment release in 2008 alone more than doubled that during the preceding 40 years. In this study we address possible reasons for this widespread seismicity in terms of triggering by other large events, exploring static and dynamic triggering from spatial scales of kilometres to thousands of kilometres. Static stress analysis can explain local clusters of earthquakes, for instance the four earthquakes (Mw 6.0-6.7) that occurred from 2004 to 2008 in Zhongba County. Stress models incorporating postseismic viscoelastic relaxation in addition to coseismic stress changes are consistent with the 1997 Mw 7.5 Manyi earthquake having triggered the 2001 Mw 7.9 Kokoxili earthquake ~200 km away by increasing stress near the hypocentre on a westerly splay of the main Kunlun fault rupture. We test whether quasi-static stress changes due to viscoelastic relaxation following these two large strike-slip earthquakes may have triggered some of the distant dip-slip events in 2008, and find that (a) only some of the events lie in areas of stress increase, and (b) the magnitude of the stress changes is very small (< 0.03 bars for the normal faults). We also investigate whether dynamic stresses from large earthquakes could have caused a transient weakening of the lower crust beneath the Plateau, resulting in an accelerated rate of interseismic motion and thus delayed triggering of earthquakes. Many lines of geophysical evidence suggest that the lower crust of Tibet is weakened by the presence of partial melts, and we explore whether large amplitude surface waves propagating across the Plateau may facilitate further localized or distributed weakening. We seek evidence for surface deformation transients and enhanced seismicity rates that may accompany such triggered episodes. Candidate source earthquakes are the Manyi and Kokoxili earthquakes on the Plateau itself and the 2004 Mw 9.2 Sumatra earthquake 2000 km away, whose rupture directivity was towards Tibet.

Ryder, I. M.; Burgmann, R.

2011-12-01

122

A large scale double beta and dark matter experiment: on the physics potential of GENIUS.  

NASA Astrophysics Data System (ADS)

The physics potential of GENIUS, a recently proposed double beta decay and dark matter experiment is discussed. The experiment will allow to probe neutrino masses down to 10-(2-3)eV. GENIUS will test the structure of the neutrino mass matrix, and therefore implicitly neutrino oscillation parameters comparable or superior in sensitivity to the best proposed dedicated terrestrial neutrino oscillation experiments. If the 10-3eV level is reached, GENIUS will even allow to test the large angle MSW solution of the solar neutrino problem. Even in its first stage GENIUS will confirm or rule out degenerate or inverted neutrino mass scenarios, which have been widely discussed in the literature as a possible solution to current hints on finite neutrino masses and also test the ?eý?? hypothesis of the atmospheric neutrino problem. Concerning cold dark matter search, the low background anticipated for GENIUS would, for the first time ever, allow to cover the complete MSSM neutralino parameter space, making GENIUS competitive to LHC in SUSY discovery.

Klapdor-Kleingrothaus, H. V.; Hirsch, M.

1997-12-01

123

Evolutionary potential of a large marine vertebrate: quantitative genetic parameters in a wild population.  

PubMed

Estimating quantitative genetic parameters ideally takes place in natural populations, but relatively few studies have overcome the inherent logistical difficulties. For this reason, no estimates currently exist for the genetic basis of life-history traits in natural populations of large marine vertebrates. And yet such estimates are likely to be important given the exposure of this taxon to changing selection pressures, and the relevance of life-history traits to population productivity. We report such estimates from a long-term (1995-2007) study of lemon sharks (Negaprion brevirostris) conducted at Bimini, Bahamas. We obtained these estimates by genetically reconstructing a population pedigree (117 dams, 487 sires, and 1351 offspring) and then using an "animal model" approach to estimate quantitative genetic parameters. We find significant additive genetic (co)variance, and hence moderate heritability, for juvenile length and mass. We also find substantial maternal effects for these traits at age-0, but not age-1, confirming that genotype-phenotype interactions between mother and offspring are strongest at birth; although these effects could not be parsed into their genetic and nongenetic components. Our results suggest that human-imposed selection pressures (e.g., size-selective harvesting) might impose noteworthy evolutionary change even in large marine vertebrates. We therefore use our findings to explain how maternal effects may sometimes promote maladaptive juvenile traits, and how lemon sharks at different nursery sites may show "constrained local adaptation." We also show how single-generation pedigrees, and even simple marker-based regression methods, can provide accurate estimates of quantitative genetic parameters in at least some natural systems. PMID:19236474

Dibattista, Joseph D; Feldheim, Kevin A; Garant, Dany; Gruber, Samuel H; Hendry, Andrew P

2009-04-01

124

Analysis of Potential for Titanium Liner Buckling after Proof in a Large Kevlar/Epoxy COPV  

NASA Technical Reports Server (NTRS)

We analyze the potential for liner buckling in a 40-in Kevlar49/epoxy overwrapped spherical pressure vessel (COPV) due to long, local depressions or valleys in the titanium liner, which appeared after proof testing (autofrettage). We begin by presenting the geometric characteristics of approximately 20 mil (0.02 in.) deep depressions measured by laser profilometry in several vessels. While such depths were more typical, depths of more than 40 mils (0.02 in.) were seen near the equator in one particular vessel. Such depressions are largely the result of overlap of the edges of overwrap bands (with rectangular cross-section prepreg tows) from the first or second wrap patterns particularly where they start and end. We then discuss the physical mechanisms of formation of the depressions during the autofrettage process in terms of uneven void compaction in the overwrap around the tow overlap lines and the resulting 10-fold increase in through-thickness stiffness of the overwrap. We consider the effects of liner plastic yielding mechanisms in the liner on residual bending moments and interface pressures with the overwrap both at the peak proof pressure (approx.6500 psi) and when reducing the pressure to 0 psi. During depressurization the Bauschinger phenomenon becomes very important whereby extensive yielding in tension reduces the magnitude of the yield threshold in compression by 30 to 40%, compared to the virgin annealed state of the liner titanium. In the absence of a depression, the liner is elastically stable in compression even at liner overwrap interface pressures nominally 6 times the approx. 1000 psi interface pressure that exists at 0 psi. Using a model based on a plate-on-an-elastic-foundation, we develop an extensive analysis of the possible destabilizing effects of a frozen-in valley. The analysis treats the modifying effects of the residual bending moments and interface pressures remaining after the proof hold as well as the Bauschinger effect on the compressive yield threshold. The key result is that depression depths of up to 40 mils can be tolerated, but above 40 mils, the Bauschinger effect drives destabilization, and buckling becomes increasingly likely depending on the details of depression formation during autofrettage. It is almost certain that destabilization and buckling will occur for depression depths beyond 55 mils. The main equations and formulas for treating the various phases of depression development and potential buckling, are only briefly outlined in the paper, but are available from the authors.

Phoenix, S. Leigh; Kezirian, Michael T.

2009-01-01

125

Metal-Encapsulated Caged Clusters of Germanium with Large Gaps and Different Growth Behavior than Silicon  

NASA Astrophysics Data System (ADS)

Metal ( M)-encapsulated caged clusters of Ge are studied using the ab initio pseudopotential plane-wave method and the generalized gradient approximation for the exchange-correlation energy. Depending upon the size of the M atom, we find Frank-Kasper polyhedral M@Ge16 for M= Ti, Zr, Hf, and capped decahedral or cubic M@Ge14 and M@Ge15 clusters for several M atoms. The growth behavior differs from the one found in M@Sin clusters. The highest-occupied-lowest-unoccupied molecular orbital gaps are, however, similarly large or even higher in some cases. Cr@Ge16 and Fe@Ge15 are magnetic. The weak interaction between the clusters makes such species attractive for cluster assembled materials.

Kumar, Vijay; Kawazoe, Yoshiyuki

2002-06-01

126

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. PMID:24893601

2014-01-01

127

Abundance variations and first ionization potential trends during large stellar flares  

NASA Astrophysics Data System (ADS)

Context: In the solar corona, elements of low first ionization potential (FIP ? 10 eV) are enriched relative to their abundances in the photosphere, while high-FIP abundances remain unchanged. This was labeled as the Solar FIP effect. High-resolution X-ray spectroscopy has revealed that active stellar coronae show an opposite effect, which was labeled the inverse-FIP (IFIP) effect. The correlation found between coronal activity and the FIP/IFIP bias suggests that flaring activity is involved in switching from FIP to IFIP. Aims: This work aims at a more systematic understanding of the FIP trends during stellar flares and complements an earlier study based on Chandra alone. Methods: The eight brightest X-ray flares observed with XMM-Newton are analyzed and compared with their respective quiescence states. Together with six previous flares observed with Chandra, this establishes the best currently available sample of flares. We look for abundance variations during the flare and their correlation with FIP. For that purpose, we define a new FIP bias measure. Results: A trend is found where coronae that are IFIP-biased in quiescence, show a FIP bias during flares relative to their quiescence composition. This effect is reversed for coronae that are FIP-biased in quiescence. The observed trend is thus consistent with chromospheric evaporation rather than with a FIP mechanism operating during flares. It also suggests that the quiescent IFIP bias is real and that the large flares are not the direct cause of the IFIP effect in stellar coronae.

Nordon, R.; Behar, E.

2008-05-01

128

Damage mechanism at different transpassive potentials of solution-annealed 316 and 316l stainless steels  

NASA Astrophysics Data System (ADS)

Electrochemical impedance spectroscopy (EIS), anodic polarization and scanning electron microscopy techniques were used to investigate the damage mechanism in the transpassive potential region of AISI 316 and AISI 316L solution-annealed stainless steels (SS) with different degrees of sensitization. Depending on the DC potential applied during EIS tests, the AC responses in the transpassive region included three different regions: the first one associated with anodic dissolution of the passive layer, the second one contributed to the dissolution at the area near grain boundaries, and the last one attributed to pitting corrosion. In addition, the fitting results to experimental data showed that as the DC bias during the EIS test increases the charge transfer resistance ( R ct) decreases. Moreover, the R ct values decreased as the sensitization temperature increases but the AISI 316L SS samples exhibited a higher resistance to intergranular corrosion than 316 SS samples.

Morshed Behbahani, K.; Pakshir, M.; Abbasi, Z.; Najafisayar, P.

2015-01-01

129

When species' ranges meet: assessing differences in habitat selection between sympatric large carnivores.  

PubMed

Differentiation in habitat selection among sympatric species may depend on niche partitioning, species interactions, selection mechanisms and scales considered. In a mountainous area in Sweden, we explored hierarchical habitat selection in Global Positioning System-collared individuals of two sympatric large carnivore species; an obligate predator, the Eurasian lynx (Lynx lynx), and a generalist predator and scavenger, the wolverine (Gulo gulo). Although the species' fundamental niches differ widely, their ranges overlap in this area where they share a prey base and main cause of mortality. Both lynx and wolverines selected for steep and rugged terrain in mountainous birch forest and in heaths independent of scale and available habitats. However, the selection of lynx for their preferred habitats was stronger when they were forming home ranges and they selected the same habitats within their home ranges independent of home range composition. Wolverines displayed a greater variability when selecting home ranges and habitat selection also varied with home range composition. Both species selected for habitats that promote survival through limited encounters with humans, but which also are rich in prey, and selection for these habitats was accordingly stronger in winter when human activity was high and prey density was low. We suggest that the observed differences between the species result primarily from different foraging strategies, but may also depend on differences in ranging and resting behaviour, home range size, and relative density of each species. Our results support the prediction that sympatric carnivores with otherwise diverging niches can select for the same resources when sharing main sources of food and mortality. PMID:23242426

Rauset, Geir Rune; Mattisson, Jenny; Andrén, Henrik; Chapron, Guillaume; Persson, Jens

2013-07-01

130

Analysis of gender based differences in auditory evoked potentials among healthy elderly population  

PubMed Central

Background: Influence of gender on auditory evoked potentials is contentious. Although there are quite a few studies documenting the gender as an influencing factor on auditory evoked potentials in younger subjects, but there is a lack of similar studies among elderly population. The present study was conducted to find out the pattern of gender based differences in auditory evoked potentials among healthy elderly subjects. Materials and Methods: A cross-sectional study was conducted on age matched, healthy males (n = 35) and females (n = 34), aged 50-70 years. The measures included latencies of waves I-V and interpeak latencies (IPL) I-III, III-V and I-V separately for both ears. Data was analyzed statistically using Students unpaired t-test, using Statistical Package for Social Sciences software v13.0. Results: The values of all the latencies and IPL for both the ears were non-significantly higher (P > 0.05) in males as compared to females. These results may be attributed to the differences in head circumference between both the genders and to the changed hormonal milieu of sex hormones after menopause. Conclusions: Statistical insignificance of latencies among male and female elderly subjects excludes gender as an influencing factor on auditory evoked potentials in this age group. PMID:25371865

Gupta, Sharat; Mittal, Shallu; Baweja, Pooja; Kumar, Avnish; Singh, Kamal Dev; Sharma, Raghuvansh

2014-01-01

131

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

132

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'. PMID:19171027

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

133

The effective fragment potential method. An approximate ab initio mo method for large molecules  

NASA Astrophysics Data System (ADS)

The effective fragment potential (EFP) approximation within the ab initio MO method is proposed. Only the active electrons of a molecule are explicitly taken into account, the rest of the molecule being replaced by an effective potential. Considering, NH 3 as a two-electron system. the potential parameters have been determined and tested for various complexes.

Ohta, Katsuhisa; Yoshioka, Yasunori; Morokuma, Keiji; Kitaura, Kazuo

1983-10-01

134

Variation in free-radical damage in rice cell suspensions with different embryogenic potentials  

Microsoft Academic Search

Levels of free-radical-mediated lipid peroxidation were monitored in cell-suspension cultures of Oryza sativa L. possessing different embryogenic potentials. Oxidative stress was evaluated using assays which sequentially assessed the stages of lipid peroxidation (diene conjugation, peroxidation, and the formation of secondary lipid-peroxidation products). Lipid peroxidation was significantly higher in a cell line which had lost embryogenic ability compared with lines which

Erica E. Benson; Paul T. Lynch; June Jones

1992-01-01

135

Water potentials of Salsola kali L. at differing levels of substrate water availability  

Microsoft Academic Search

Summary  Isolated embryos of Salsola kali L. (Russian thistle) were allowed to imbibe on filter paper in Peltier thermocouple psychrometer chambers with differing\\u000a amounts of water available. Water potential determinations were made on the embryo-filter paper system periodically during\\u000a the 24-h period of imbibition and early seedling growth. At the 24th h, complete extension of the embryonic axis occurred\\u000a at an

Walter T. McDonough

1975-01-01

136

Differences between discontinuous and continuous soft-core attractive potentials: The appearance of density anomaly  

Microsoft Academic Search

Soft-core attractive potentials can give rise to a phase diagram with three fluid phases at different densities (gas, low-density liquid and high-density liquid), separated by first order phase transition lines ending in critical points. Experiments show a phase diagram with these features for phosphorous and triphenyl phosphite. Liquid–liquid phase transition could be relevant for water, silica, liquid metals, colloids and

Giancarlo Franzese; Departament de Fisica Fonamental; Facultat de Fisica

2007-01-01

137

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

138

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

139

Frequency Spectrum of Transepithelial Potential Difference Reveals Transport-Related Oscillations  

PubMed Central

How epithelia transport fluid is a fundamental issue that is unresolved. Explanations offered include molecular engines, local transcellular osmosis, local paracellular osmosis, and paracellular fluid transport. On the basis of experimental and theoretical work done on corneal endothelium, a fluid transporting epithelium, we suggest electroosmotic coupling at the level of the intercellular junctions driven by the transendothelial electrical potential difference as an explanation of paracellular fluid transport. We collect frequency spectra of that potential difference in real-time. For what we believe is the first time for any epithelium, we report that, unexpectedly, the potential difference displays oscillations at many characteristic frequencies. We also show that on both stimulating cell activity and inhibiting ion transport mechanisms, there are corresponding changes in the oscillations amplitudes that mirror changes known previously in rates of fluid transport. We believe these findings provide a novel tool to study the kinetics of electrogenic elements such as channels and transporters, which from this evidence would give rise to current oscillations with characteristic periods going from 150 ms to 8 s. PMID:19751657

Montalbetti, Nicolás; Fischbarg, Jorge

2009-01-01

140

Identification of flubendazole as potential anti-neuroblastoma compound in a large cell line screen  

PubMed Central

Flubendazole was shown to exert anti-leukaemia and anti-myeloma activity through inhibition of microtubule function. Here, flubendazole was tested for its effects on the viability of in total 461 cancer cell lines. Neuroblastoma was identified as highly flubendazole-sensitive cancer entity in a screen of 321 cell lines from 26 cancer entities. Flubendazole also reduced the viability of five primary neuroblastoma samples in nanomolar concentrations thought to be achievable in humans and inhibited vessel formation and neuroblastoma tumour growth in the chick chorioallantoic membrane assay. Resistance acquisition is a major problem in high-risk neuroblastoma. 119 cell lines from a panel of 140 neuroblastoma cell lines with acquired resistance to various anti-cancer drugs were sensitive to flubendazole in nanomolar concentrations. Tubulin-binding agent-resistant cell lines displayed the highest flubendazole IC50 and IC90 values but differences between drug classes did not reach statistical significance. Flubendazole induced p53-mediated apoptosis. The siRNA-mediated depletion of the p53 targets p21, BAX, or PUMA reduced the neuroblastoma cell sensitivity to flubendazole with PUMA depletion resulting in the most pronounced effects. The MDM2 inhibitor and p53 activator nutlin-3 increased flubendazole efficacy while RNAi-mediated p53-depletion reduced its activity. In conclusion, flubendazole represents a potential treatment option for neuroblastoma including therapy-refractory cells. PMID:25644037

Michaelis, Martin; Agha, Bishr; Rothweiler, Florian; Löschmann, Nadine; Voges, Yvonne; Mittelbronn, Michel; Starzetz, Tatjana; Harter, Patrick N.; Abhari, Behnaz A.; Fulda, Simone; Westermann, Frank; Riecken, Kristoffer; Spek, Silvia; Langer, Klaus; Wiese, Michael; Dirks, Wilhelm G.; Zehner, Richard; Cinatl, Jaroslav; Wass, Mark N.; Cinatl, Jindrich

2015-01-01

141

Identification of flubendazole as potential anti-neuroblastoma compound in a large cell line screen.  

PubMed

Flubendazole was shown to exert anti-leukaemia and anti-myeloma activity through inhibition of microtubule function. Here, flubendazole was tested for its effects on the viability of in total 461 cancer cell lines. Neuroblastoma was identified as highly flubendazole-sensitive cancer entity in a screen of 321 cell lines from 26 cancer entities. Flubendazole also reduced the viability of five primary neuroblastoma samples in nanomolar concentrations thought to be achievable in humans and inhibited vessel formation and neuroblastoma tumour growth in the chick chorioallantoic membrane assay. Resistance acquisition is a major problem in high-risk neuroblastoma. 119 cell lines from a panel of 140 neuroblastoma cell lines with acquired resistance to various anti-cancer drugs were sensitive to flubendazole in nanomolar concentrations. Tubulin-binding agent-resistant cell lines displayed the highest flubendazole IC50 and IC90 values but differences between drug classes did not reach statistical significance. Flubendazole induced p53-mediated apoptosis. The siRNA-mediated depletion of the p53 targets p21, BAX, or PUMA reduced the neuroblastoma cell sensitivity to flubendazole with PUMA depletion resulting in the most pronounced effects. The MDM2 inhibitor and p53 activator nutlin-3 increased flubendazole efficacy while RNAi-mediated p53-depletion reduced its activity. In conclusion, flubendazole represents a potential treatment option for neuroblastoma including therapy-refractory cells. PMID:25644037

Michaelis, Martin; Agha, Bishr; Rothweiler, Florian; Löschmann, Nadine; Voges, Yvonne; Mittelbronn, Michel; Starzetz, Tatjana; Harter, Patrick N; Abhari, Behnaz A; Fulda, Simone; Westermann, Frank; Riecken, Kristoffer; Spek, Silvia; Langer, Klaus; Wiese, Michael; Dirks, Wilhelm G; Zehner, Richard; Cinatl, Jaroslav; Wass, Mark N; Cinatl, Jindrich

2015-01-01

142

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

143

Potential Mechanisms for Racial and Ethnic Differences in Antimüllerian Hormone and Ovarian Reserve  

PubMed Central

Accumulating evidence suggests that reproductive potential and function may be different across racial and ethnic groups. Racial differences have been demonstrated in pubertal timing, infertility, outcomes after assisted reproductive technology (ART) treatment, and reproductive aging. Recently, racial differences have also been described in serum antimüllerian hormone (AMH), a sensitive biomarker of ovarian reserve, supporting the notion that ovarian reserve differs between racial/ethnic groups. The existence of such racial/ethnic differences in ovarian reserve, as reflected by AMH, may have important clinical implications for reproductive endocrinologists. However, the mechanisms which may underlie such racial differences in ovarian reserve are unclear. Various genetic factors and environmental factors such as obesity, smoking, and vitamin D deficiency which have been shown to correlate with serum AMH levels and also display significant racial/ethnic variations are discussed in this review. Improving our understanding of racial differences in ovarian reserve and their underlying causes may be essential for infertility treatment in minority women and lead to better reproductive planning, improved treatment outcomes, and timely interventions which may prolong reproductive lifespan in these women. PMID:24348557

Seifer, David B.

2013-01-01

144

Potential for large-scale submarine slope failure and tsunami generation along the US mid-Atalantic coast  

NSDL National Science Digital Library

This paper from the journal GEOLOGY, "Potential for large-scale submarine slope failure and tsunami generation along the US mid-Atlantic coast," by Neal W. Driscoll, Jeffrey K. Weissel, and John A. Goff, has made headlines in recent weeks for its claim that the outer continental shelf off the coasts of Virginia and North Carolina "might be in the initial stages of large-scale slope failure." Such failure would likely produce a significant Tsunami effect along the eastern coast.

Driscoll, Neal W.

2000-01-01

145

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

146

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

147

Using seismic sensors to detect elephants and other large mammals: a potential census technique  

Microsoft Academic Search

Summary 1. Large mammal populations are difficult to census and monitor in remote areas. In particular, elephant populations in Central Africa are difficult to census due to dense forest, making aerial surveys impractical. Conservation management would be improved by a census technique that was accurate and precise, did not require large efforts in the field, and could record numbers of

JASON D. WOOD; CAITLIN E. O'CONNELL-RODWELL; SIMON L. KLEMPERER

2005-01-01

148

Hamilton's principle: why is the integrated difference of kinetic and potential energy minimized?  

E-print Network

I present an intuitive answer to an often asked question: why is the integrated difference K-U between the kinetic and potential energy the quantity to be minimized in Hamilton's principle? Using elementary arguments, I map the problem of finding the path of a moving particle connecting two points to that of finding the minimum potential energy of a static string. The mapping implies that the configuration of a non--stretchable string of variable tension corresponds to the spatial path dictated by the Principle of Least Action; that of a stretchable string in space-time is the one dictated by Hamilton's principle. This correspondence provides the answer to the question above: while a downward force curves the trajectory of a particle in the (x,t) plane downward, an upward force of the same magnitude stretches the string to the same configuration x(t).

Alberto G. Rojo

2005-04-02

149

Differences in regional substitution pattern in the human genome created patterns of large-scale variations of base composition known as genomic isochores. Different regions of the human  

E-print Network

) Modeling of Neighbor-Dependent Mutation in DNA Sequence Evolution. Journal of Computational Biology 10: 313Abstract Differences in regional substitution pattern in the human genome created patterns of large-scale variations of base composition known as genomic isochores. Different regions of the human genome show

Spang, Rainer

150

Polysynaptic Potentiation at Different Levels of Rat Olfactory Pathways Following Learning  

PubMed Central

This study was aimed at investigating the consequences of learning on late polysynaptic components of evoked field potential signals recorded in parallel at different levels of the olfactory pathways. For this, evoked field potentials induced by electrical stimulation of the olfactory bulb were recorded simultaneously in the anterior piriform cortex, the posterior piriform cortex, the lateral entorhinal cortex, and the dentate gyrus. The different parameters of late components were measured in each site before and after completion of associative learning in anesthetized rats. In the learning task, rats were trained to associate electrical stimulation of one olfactory bulb electrode with the delivery of sucrose (positive reward) and stimulation of a second olfactory bulb electrode with the delivery of quinine (negative reward). In this way, stimulation of the same olfactory bulb electrodes used for inducing field potentials served as a discriminative cue in the learning paradigm. The data confirmed previous observation that learning was associated with a lowering in late-component-1 intensity of induction in the posterior piriform cortex. The use of simultaneous recording allowed us to further specify the consequences of learning on late-component distribution in the studied network. Indeed the data showed that whereas before learning, late component 1 was rather uniformly distributed among the recorded sites; following learning, its expression was facilitated preferentially in the posterior piriform cortex and lateral entorhinal cortex. Furthermore, learning was accompanied by the emergence of a new late component (late component 2), which occurred simultaneously in the four recording sites. The possible involvement of potentiation of polysynaptic components in recognition and/or consolidation processes will be discussed. PMID:11992017

Mouly, Anne Marie; Gervais, Rémi

2002-01-01

151

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

PubMed Central

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

2013-01-01

152

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

153

Visual evoked potentials findings in non-affected subjects from a large Brazilian pedigree of 11778 Leber's hereditary optic neuropathy.  

PubMed

To investigate pattern-reversal visual evoked potentials (PRVEP) in asymptomatic maternally and non-maternally related members from a large Brazilian 11778/ND4 LHON pedigree. Transient PRVEP for check sizes 15' and 60' were recorded from asymptomatic mutation carriers and non-mutant descendants of affected/non-affected males, all with best-corrected visual acuity of 20/20. A control group of spouses (off-pedigree) was also included. Parameters of N75, P100 and N135 latencies (ms) and N75-P100 peak-to-peak amplitude (?V) as well as temporal dispersion (latency of N135-latency of N75) were determined. Longitudinal testing was obtained in a subseries of carriers in three annual consecutive visits. We tested 48 asymptomatic mutation carriers, 19 descendants of affected males, 9 descendants of non-affected males and 27 off-pedigrees, all of the latter being non-mutant. All non-mutant male descendants did not differ from off-pedigree controls. Statistically prolonged P100 latencies were found in mutation carriers (P = 0.0143) when compared with off-pedigrees for check sizes 15', as well as significantly larger temporal dispersions for both check size 15' (P = 0.0012) and check size 60' (P = 0.0271). Serial testing in 15 mutation carriers disclosed prolonged P100 latencies and larger temporal dispersion that did not change over time. Subclinical PRVEP abnormalities were detected in this large group of asymptomatic carriers of the 11778/ND4 LHON mutation from the same family, confirming and extending previous psychophysical and structural findings of a selective involvement of the parvocellular pathway. PRVEP is a useful test to characterize and monitor visual dysfunction in this devastating disease. PMID:20676915

Sacai, Paula Yuri; Salomão, Solange Rios; Carelli, Valerio; Pereira, Josenilson Martins; Belfort, Rubens; Sadun, Alfredo Arrigo; Berezovsky, Adriana

2010-10-01

154

This information sheet is for the care and use of Sheep Potential Injury and Zoonotic Diseases: Sheep are large domestic  

E-print Network

This information sheet is for the care and use of Sheep Potential Injury and Zoonotic Diseases: Sheep are large domestic animals that are normally docile. However, they can become dangerous especially when isolated from their flock. Jumping is common in sheep and they can jump with enough force to break

Wood, Marcelo A.

155

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

156

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

157

Local contact potential difference of molecular self-assemblies investigated by Kelvin probe force microscopy  

NASA Astrophysics Data System (ADS)

Self-assembled pi-conjugated oligomer nanowires have been investigated by frequency modulation atomic force microscopy and amplitude modulation Kelvin probe force microscopy under ultra high vacuum. The distance dependence of the contact potential difference (CPD) has been analyzed by combining high resolution imaging with distance-spectroscopy measurements. It is shown that the apparition of a damping contrast characterizes the onset of short range electrostatic (SRE) forces, which are responsible for the occurrence of local CPD (LCPD) modulations correlated with the molecular lattice. By working at the onset of the damping contrast, the tip-surface separation can be adjusted to minimize the contribution of SRE forces to the measured CPD.

Spadafora, Evan J.; Linares, Mathieu; Nisa Yahya, Wan Zaireen; Lincker, Frédéric; Demadrille, Renaud; Grevin, Benjamin

2011-12-01

158

Phytoremediation Potential of Cadmium-Contaminated Soil by Eucalyptus globulus Under Different Coppice Systems.  

PubMed

The objective of this research was to determine the phytoremediation potential of Eucalyptus globulus in Cd contaminated soil through two different harvest methods. Although replanting is more expensive than coppicing and produces less aboveground biomass, more Cd can be removed from the soil with roots removal at each harvest as the E. globulus absorbs vast majority of heavy metals in non-metabolically active parts like roots. Despite the higher cost of replanting in a single harvest, when phytoremediation efficiency and total duration are considered as important factors, the replanting treatment should be recommended as an appropriate method which can decrease the phytoremediation time obviously. PMID:25543544

Luo, Jie; Qi, Shihua; Peng, Li; Xie, Xianming

2015-03-01

159

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. PMID:24782041

Nätt, Daniel; Agnvall, Beatrix; Jensen, Per

2014-01-01

160

Potential Climatic Impacts and Reliability of Very Large-Scale Wind Farms  

E-print Network

Meeting future world energy needs while addressing climate change requires large-scale deployment of low or zero greenhouse gas (GHG) emission technologies such as wind energy. The widespread availability of wind power has ...

Prinn, Ronald G.

161

Potential of mean force of association of large hydrophobic particles: towards the nanoscale limit  

PubMed Central

The potentials of mean force (PMFs) were determined, in both water with the TIP3P water model and in vacuo, for systems involving formation of nonpolar dimers composed of bicyclooctane, adamantane (both an all-atom model and a sphere with the radius of 3.4 Å representing adamantane), and fullerene, respectively. A series of umbrella-sampling molecular dynamics simulations with the AMBER force field were carried out for each pair, under both environmental conditions. The PMFs were calculated by using the Weighted Histogram Analysis Method (WHAM). The results were compared with our previously-determined PMF for neopentane. The shape of the PMFs for dimers of all four nonpolar molecules is characteristic of hydrophobic interactions with contact and solvent-separated minima, and desolvation maxima. The positions of all these minima and maxima change with the size of the nonpolar molecule; for larger molecules they shift toward larger distances. Comparison of the PMFs of the bicyclooctane, adamantane, and fullerene dimers in water and in vacuo shows that hydrophobic interactions in each dimer are different from that for the dimer of neopentane. Interactions in the bicyclooctane, adamantane, and fullerene dimers are stronger in vacuo than in water. These dimers cannot be treated as classical spherical hydrophobic objects. The solvent contribution to the PMF was also computed by subtracting the PMF determined in vacuo from that in explicit solvent. The solvent contribution to the PMFs of bicyclooctane, adamantane, and fullerene is positive as opposed to that of neopentane. The water molecules in the first solvation sphere of both adamantane and neopentane dimers are more ordered compared to bulk water, with their dipole moments pointing away from the surface of the dimers. The average number of hydrogen bonds per water molecule in the first hydration shell of adamantane is smaller compared to that in bulk water, but this shell is thicker for all-atom adamantane than for neopentane or a spherical model of adamantane. In the second hydration shell, the average number of hydrogen bonds is greater compared to that in bulk water only for neopentane and a spherical model of adamantane but not for the all-atom model. The strength of the hydrophobic interactions shows a linear dependence on the number of carbon atoms both in water and in vacuo. Smaller nonpolar particles interact more strongly in water than in vacuo. For larger molecules such as bicyclooctane, adamanatane and fullerene, the reversed tendency is observed. PMID:20039620

Makowski, Mariusz; Czaplewski, Cezary; Liwo, Adam; Scheraga, Harold A.

2010-01-01

162

Potential of mean force of association of large hydrophobic particles: toward the nanoscale limit.  

PubMed

The potentials of mean force (PMFs) were determined, in both water with the TIP3P water model and in vacuo, for systems involving formation of nonpolar dimers composed of bicyclooctane, adamantane (both an all-atom model and a sphere with the radius of 3.4 A representing adamantane), and fullerene, respectively. A series of umbrella-sampling molecular dynamics simulations with the AMBER force field were carried out for each pair under both environmental conditions. The PMFs were calculated by using the weighted histogram analysis method. The results were compared with our previously determined PMF for neopentane. The shape of the PMFs for dimers of all four nonpolar molecules is characteristic of hydrophobic interactions with contact and solvent-separated minima and desolvation maxima. The positions of all these minima and maxima change with the size of the nonpolar molecule; for larger molecules they shift toward larger distances. Comparison of the PMFs of the bicyclooctane, adamantane, and fullerene dimers in water and in vacuo shows that hydrophobic interactions in each dimer are different from that for the dimer of neopentane. Interactions in the bicyclooctane, adamantane, and fullerene dimers are stronger in vacuo than in water. These dimers cannot be treated as classical, spherical, hydrophobic objects. The solvent contribution to the PMF was also computed by subtracting the PMF determined in vacuo from that in explicit solvent. The solvent contribution to the PMFs of bicyclooctane, adamantane, and fullerene is positive, as opposed to that of neopentane. The water molecules in the first solvation sphere of both adamantane and neopentane dimers are more ordered as compared to bulk water, with their dipole moments pointing away from the surface of the dimers. The average number of hydrogen bonds per water molecule in the first hydration shell of adamantane is smaller compared to that in bulk water, but this shell is thicker for all-atom adamantane than for neopentane or a spherical model of adamantane. In the second hydration shell, the average number of hydrogen bonds is greater compared to that in bulk water only for neopentane and a spherical model of adamantane but not for the all-atom model. The strength of the hydrophobic interactions shows a linear dependence on the number of carbon atoms both in water and in vacuo. Smaller nonpolar particles interact more strongly in water than in vacuo. For larger molecules, such as bicyclooctane, adamantane and fullerene, the reversed tendency is observed. PMID:20039620

Makowski, Mariusz; Czaplewski, Cezary; Liwo, Adam; Scheraga, Harold A

2010-01-21

163

Potential Climatic Impacts and Reliability of Large-Scale Offshore Wind Farms  

E-print Network

The vast availability of wind power has fueled substantial interest in this renewable energy source as a potential near-zero greenhouse gas emission technology for meeting future world energy needs while addressing the ...

Wang, Chien

164

Heavy Quark Potential at Finite Temperature in a Dual Gravity Closer to Large N QCD  

E-print Network

In gauge-gravity duality, heavy quark potential at finite temperature is usually calculated with the pure AdS background, which does not capture the renormalisation group (RG) running in the gauge theory part and the potential also does not contain any confining term in the deconfined phase. Following the developments in \\cite{KS}, a geometry was contructed recently in \\cite{ Mia:NPB2010, Mia:PRD2010}, which captures the RG flow similar to QCD and we employ their geometry to obtain the heavy quark potential by analytically continuing the string configurations into the complex plane. In addition to the attractive terms, the obtained potential has confining terms both at $T=0$ and $T \

Patra, Binoy Krishna

2014-01-01

165

Heavy Quark Potential at Finite Temperature in a Dual Gravity Closer to Large N QCD  

E-print Network

In gauge-gravity duality, heavy quark potential at finite temperature is usually calculated with the pure AdS background, which does not capture the renormalisation group (RG) running in the gauge theory part and the potential also does not contain any confining term in the deconfined phase. Following the developments in \\cite{KS}, a geometry was contructed recently in \\cite{ Mia:NPB2010, Mia:PRD2010}, which captures the RG flow similar to QCD and we employ their geometry to obtain the heavy quark potential by analytically continuing the string configurations into the complex plane. In addition to the attractive terms, the obtained potential has confining terms both at $T=0$ and $T \

Binoy Krishna Patra; Himanshu Khanchandani

2014-12-16

166

Using event-related potentials to examine hemispheric differences in semantic processing.  

PubMed

Event-related potentials (ERPs) were used as the dependent measure in a divided visual field study examining the processing of lexically ambiguous words in the cerebral hemispheres. The goal was to determine if the N400 ERP component is sensitive measure of hemispheric differences in semantic processing. ERP waveforms were examined for lateralized target words that were related to either the dominant (MONEY) or subordinate (RIVER) meanings of ambiguous words (BANK). These waveforms were compared to trials where the prime-target pairs were unrelated. Reliable N400s, reflecting a significant difference between related and unrelated trials, were seen when targets were presented to the right visual field/left hemisphere. However, there were no N400s observed for either the dominant or subordinate conditions when targets were presented to the left visual field/right hemisphere. PMID:14607133

Atchley, Ruth Ann; Kwasny, Kristin M

2003-11-01

167

Investigation of potential waste material insulating properties at different temperature for thermal storage application  

NASA Astrophysics Data System (ADS)

Thermal energy storage system (TES) is developed to extend the operation of power generation. TES system is a key component in a solar energy power generation plant, but the main issue in designing the TES system is its thermal capacity of storage materials, e.g. insulator. This study is focusing on the potential waste material acts as an insulator for thermal energy storage applications. As the insulator is used to absorb heat, it is needed to find suitable material for energy conversion and at the same time reduce the waste generation. Thus, a small-scale experimental testing of natural cooling process of an insulated tank within a confined room is conducted. The experiment is repeated by changing the insulator from the potential waste material and also by changing the heat transfer fluid (HTF). The analysis presented the relationship between heat loss and the reserved period by the insulator. The results show the percentage of period of the insulated tank withstands compared to tank insulated by foam, e.g. newspaper reserved the period of 84.6% as much as foam insulated tank to withstand the heat transfer of cooking oil to the surrounding. The paper finally justifies the most potential waste material as an insulator for different temperature range of heat transfer fluid.

Ali, T. Z. S.; Rosli, A. B.; Gan, L. M.; Billy, A. S.; Farid, Z.

2013-12-01

168

Estimating Sugarcane Yield Potential Using an In-Season Determination of Normalized Difference Vegetative Index  

PubMed Central

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 (r2 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 (r2 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

169

Electrochemical potentials of potassium in skeletal muscle under different metabolic states.  

PubMed

Intracellular potassium and membrane potential were measured simultaneously by means of double-barrelled liquid ion-exchange microelectrodes in single fibers of rat thigh muscle in vivo in rats maintained in seven different metabolic states. The K+ equilibrium potential (EK) was more negative than the simultaneously measured membrane potential (Em) in the normal state by 18.4 mV. K+ loading, acute and chronic, resulted in depolarization of Em due to increased serum K+ (hyperkalemia) with no increase in intracellular K+. K+ depletion resulted in hyperpolarization of Em as plasma K+ decreased proportionately more than intracellular K+. Low Na+ diet had no effect. Intracellular K+ was decreased in acute acidosis but not in the chronic state. Thus K+ depletion and acute acidosis are associated with intracellular K+ decrease. The fact that hyperpolarization exists in the former and not the latter is a reflection that hypokalemia accompanies the former condition. The hyperpolarizing states of K+ depletion and chronic acidosis are accompanied by decreased excitability and muscle weakness. PMID:1447314

Khuri, R N; Agulian, S K; Abdulnour-Nakhoul, S; Nakhoul, N L

1992-12-01

170

Quantitative proteome analysis of HCC cell lines with different metastatic potentials by SILAC.  

PubMed

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide and metastasis is the main cause for treatment failure and high fatality of HCC. In order to make further exploration into the mechanism of HCC metastasis and to search for the candidates of diagnostic marker and therapeutic target, stable-isotope labeling by amino acids in cell culture (SILAC) technique was employed to conduct differential proteome analysis on HCC cell lines--MHCC97L and HCCLM6 with low and high metastatic potentials. In total, 2335 reliable proteins were identified using LTQ-FT mass spectrum, among which 91 proteins were upregulated and 61 proteins were downregulated in HCCLM6. Most of the upregulated proteins were involved in adherence, morphogenesis, and lipid synthesis, while lots of the downregulated proteins were involved in electron transport, which might be crucial for HCC metastasis. Six dysregulated proteins were validated by Western blotting in the cell lines. Interestingly, the upregulation of solute carrier family 12 member 2 (SLC 12A2) and protein disulfide-isomerase A4 (PDIA4) were further confirmed in the culture supernatants by Western blotting and in the sera of HCC patients with different metastatic potentials by ELISA. Our study provided not only the valuable insights into the HCC metastasis mechanisms but also the potential candidate biomarkers for prediction of HCC metastasis. PMID:19016532

Chen, Ning; Sun, Wei; Deng, Xinyu; Hao, Yunwei; Chen, Xilin; Xing, Baocai; Jia, Wei; Ma, Jie; Wei, Handong; Zhu, Yunping; Qian, Xiaohong; Jiang, Ying; He, Fuchu

2008-12-01

171

Torque measurements reveal large process differences between materials during high solid enzymatic hydrolysis of pretreated lignocellulose  

PubMed Central

Background A common trend in the research on 2nd generation bioethanol is the focus on intensifying the process and increasing the concentration of water insoluble solids (WIS) throughout the process. However, increasing the WIS content is not without problems. For example, the viscosity of pretreated lignocellulosic materials is known to increase drastically with increasing WIS content. Further, at elevated viscosities, problems arise related to poor mixing of the material, such as poor distribution of the enzymes and/or difficulties with temperature and pH control, which results in possible yield reduction. Achieving good mixing is unfortunately not without cost, since the power requirements needed to operate the impeller at high viscosities can be substantial. This highly important scale-up problem can easily be overlooked. Results In this work, we monitor the impeller torque (and hence power input) in a stirred tank reactor throughout high solid enzymatic hydrolysis (< 20% WIS) of steam-pretreated Arundo donax and spruce. Two different process modes were evaluated, where either the impeller speed or the impeller power input was kept constant. Results from hydrolysis experiments at a fixed impeller speed of 10 rpm show that a very rapid decrease in impeller torque is experienced during hydrolysis of pretreated arundo (i.e. it loses its fiber network strength), whereas the fiber strength is retained for a longer time within the spruce material. This translates into a relatively low, rather WIS independent, energy input for arundo whereas the stirring power demand for spruce is substantially larger and quite WIS dependent. By operating the impeller at a constant power input (instead of a constant impeller speed) it is shown that power input greatly affects the glucose yield of pretreated spruce whereas the hydrolysis of arundo seems unaffected. Conclusions The results clearly highlight the large differences between the arundo and spruce materials, both in terms of needed energy input, and glucose yields. The impact of power input on glucose yield is furthermore shown to vary significantly between the materials, with spruce being very affected while arundo is not. These findings emphasize the need for substrate specific process solutions, where a short pre-hydrolysis (or viscosity reduction) might be favorable for arundo whereas fed-batch might be a better solution for spruce. PMID:22867035

2012-01-01

172

Large Regional Differences in Serological Follow-Up of Q Fever Patients in The Netherlands  

PubMed Central

Background During the Dutch Q fever epidemic more than 4,000 Q fever cases were notified. This provided logistical challenges for the organisation of serological follow-up, which is considered mandatory for early detection of chronic infection. The aim of this study was to investigate the proportion of acute Q fever patients that received serological follow-up, and to identify regional differences in follow-up rates and contributing factors, such as knowledge of medical practitioners. Methods Serological datasets of Q fever patients diagnosed between 2007 and 2009 (N?=?3,198) were obtained from three Laboratories of Medical Microbiology (LMM) in the province of Noord-Brabant. One LMM offered an active follow-up service by approaching patients; the other two only tested on physician's request. The medical microbiologist in charge of each LMM was interviewed. In December 2011, 240 general practices and 112 medical specialists received questionnaires on their knowledge and practices regarding the serological follow-up of Q fever patients. Results Ninety-five percent (2,226/2,346) of the Q fever patients diagnosed at the LMM with a follow-up service received at least one serological follow-up within 15 months of diagnosis. For those diagnosed at a LMM without this service, this was 25% (218/852) (OR 54, 95% CI 43–67). Although 80% (162/203) of all medical practitioners with Q fever patients reported informing patients of the importance of serological follow-up, 33% (67/203) never requested it. Conclusions Regional differences in follow-up are substantial and range from 25% to 95%. In areas with a low follow-up rate the proportion of missed chronic Q fever is potentially higher than in areas with a high follow-up rate. Medical practitioners lack knowledge regarding the need, timing and implementation of serological follow-up, which contributes to patients receiving incorrect or no follow-up. Therefore, this information should be incorporated in national guidelines and patient information forms. PMID:23577152

Morroy, Gabriëlla; Wielders, Cornelia C. H.; Kruisbergen, Mandy J. B.; van der Hoek, Wim; Marcelis, Jan H.; Wegdam-Blans, Marjolijn C. A.; Wijkmans, Clementine J.; Schneeberger, Peter M.

2013-01-01

173

Potential for large-bodied zooplankton and dreissenids to alter the productivity and autotrophic structure of lakes.  

PubMed

While limnological studies have emphasized the importance of grazers on algal biomass and primary production in pelagic habitats, few studies have examined their potential role in altering total ecosystem primary production and it's partitioning between pelagic and benthic habitats. We modified an existing ecosystem production model to include biotic feedbacks associated with two groups of large-bodied grazers of phytoplankton (large-bodied zooplankton and dreissenid mussels) and estimated their effects on total ecosystem production (TEP), and the partitioning of TEP between phytoplankton and periphyton (autotrophic structure) across large gradients in lake size and total phosphorus (TP) concentration. Model results indicated that these filter feeders were capable of reducing whole-lake phytoplankton production by 20-70%, and increasing whole-lake benthic production between 0% and 600%. Grazer effects on TEP were constrained by lake size, trophic status, and potential feedbacks between grazing and maximum rates of benthic photosynthesis (BP(MAX)). In small (mean depth Z < 10 m) oligotrophic and mesotrophic (TP < 100 mg P/m2) lakes, both large-bodied zooplankton and dreissenids were capable of increasing the benthic fraction (Bf) by 10-50% of TEP. Small lakes were also the only systems where TEP had the potential to increase in the presence of large-bodied grazers, but such increases only occurred if grazer-induced changes in water clarity, macrophyte coverage, or nutrient availability stimulated specific growth rates of periphyton. In other scenarios, TEP declined by a maximum of 50%. In very large lakes (Z > 100 m), Bf was minor (< 10%) in the presence or absence of grazers, but increases in littoral habitat and the stimulation of benthic production in these ecosystems could be of ecological relevance because littoral zones in large lakes contain a relatively high proportion of within-lake biodiversity and are important for whole-lake food webs. PMID:25230476

Higgins, Scott N; Althouse, B; Devlin, S P; Vadeboncoeur, Y; Vander Zanden, M J

2014-08-01

174

Potential significance of phenotypic heterogeneity of focal lesions at different stages in hepatocarcinogenesis.  

PubMed

In this study we used morphometric methods to investigate the number, size and phenotype of foci of altered hepatocytes in male rats after limited (7 weeks) oral administration of N-nitrosomorpholine (stop-model). We found a chronological sequence from clear and eosinophilic cell foci (CCF and ECF) of early appearance followed by intermediate and mixed (MCF) and basophilic cell foci (BCF). Eventually, neoplastic nodules (NN) and hepatocellular carcinomas (HC) developed. The animals killed first (7 weeks) showed a large number of CCF and ECF and virtually no MCF and BCF. During the following weeks, we observed a temporary increase in the number of MCF and a progressive decrease in the number of CCF and ECF. A few BCF appeared for the first time 5 weeks after cessation of treatment. Subsequently there was an increase in the number of BCF and a decrease in the number of MCF, the latter starting 20 weeks after withdrawal of the carcinogen. MCF were found most frequently in animals with a high incidence of CCF. BCF and tumours were found most frequently in animals with a high incidence of MCF. The increase in the number of CCF was due to the appearance of small foci of this phenotype. However, the increase in the number of MCF and BCF was not related to an increase in number of small foci of these phenotypes. On the contrary, while the total number of MCF and BCF increased, there was a decrease in the incidence of small foci, but an increase in the incidence of large foci of these phenotypes. From these results, we concluded that phenotypically different foci essentially reflect different stages in the process of hepatocarcinogenesis. Moreover, the lack of small MCF and BCF suggests that the transition from CCF and ECF to MCF and finally to BCF is the result of a conversion of large cell populations within foci from 'early' to 'late' phenotypes rather than the consequence of a repeated clonal selection. PMID:3664953

Enzmann, H; Bannasch, P

1987-11-01

175

Direction-dependent spectral sensitivity and interaural spectral difference in a dolphin: evoked potential study.  

PubMed

Sensitivity and interaural intensity difference (IID) dependence on sound frequency and direction was measured in an Amazon river dolphin Inia geoffrensis by recording the auditory nerve evoked response from the body surface. The maximal sensitivity in the horizontal plane was found when the sound direction was 5 degrees to 10 degrees ipsilateral to the recorded ear; the direction dependence of sensitivity was more pronounced at higher frequencies than at lower ones. The IID reached its peak at small azimuthal angles (7.5 degrees to 15 degrees) and higher sound frequencies (100 kHz), or at large azimuthal angles (30 degrees to 45 degrees) and lower sound frequencies (20 to 30 kHz). Each sound direction featured its specific pattern of spectral sensitivity and of interaural spectral difference. The interaural spectral difference fluctuated within a range of more than 20 dB depending on sound direction. The data indicate that interaural intensity as well as spectral difference may be cues for binaural localization of sound direction by dolphins. PMID:8326074

Supin AYa; Popov, V V

1993-06-01

176

Practical hyperdynamics method for systems with large changes in potential energy.  

PubMed

A practical hyperdynamics method is proposed to accelerate systems with highly endothermic and exothermic reactions such as hydrocarbon pyrolysis and oxidation reactions. In this method, referred to as the "adaptive hyperdynamics (AHD) method," the bias potential parameters are adaptively updated according to the change in potential energy. The approach is intensively examined for JP-10 (exo-tetrahydrodicyclopentadiene) pyrolysis simulations using the ReaxFF reactive force field. Valid boost parameter ranges are clarified as a result. It is shown that AHD can be used to model pyrolysis at temperatures as low as 1000 K while achieving a boost factor of around 10(5). PMID:25527921

Hirai, Hirotoshi

2014-12-21

177

Practical hyperdynamics method for systems with large changes in potential energy  

NASA Astrophysics Data System (ADS)

A practical hyperdynamics method is proposed to accelerate systems with highly endothermic and exothermic reactions such as hydrocarbon pyrolysis and oxidation reactions. In this method, referred to as the "adaptive hyperdynamics (AHD) method," the bias potential parameters are adaptively updated according to the change in potential energy. The approach is intensively examined for JP-10 (exo-tetrahydrodicyclopentadiene) pyrolysis simulations using the ReaxFF reactive force field. Valid boost parameter ranges are clarified as a result. It is shown that AHD can be used to model pyrolysis at temperatures as low as 1000 K while achieving a boost factor of around 105.

Hirai, Hirotoshi

2014-12-01

178

Absolute potential of the standard hydrogen electrode and the problem of interconversion of potentials in different solvents.  

PubMed

The absolute potential of the standard hydrogen electrode, SHE, was calculated on the basis of a thermodynamic cycle involving H(2(g)) atomization, ionization of H((g))* to H((g))(+), and hydration of H(+). The most up-to-date literature values on the free energies of these reactions have been selected and, when necessary, adjusted to the electron convention Fermi-Dirac statistics since both e(-) and H(+) are fermions. As a reference state for the electron, we have chosen the electron at 0 K, which is the one used in computational chemistry. Unlike almost all previous estimations of SHE, DeltaG(aq)(theta)(H(+)) was used instead of the real potential, alpha(aq)(H(+)). This choice was made to obtain a SHE value based on the chemical potential, which is the appropriate reference to be used in theoretical computations of standard reduction potentials. The result of this new estimation is a value of 4.281 V for the absolute potential of SHE. The problem of conversion of standard reduction potentials (SRPs) measured or estimated in water to the corresponding values in nonaqueous solvents has also been addressed. In fact, thermochemical cycles are often used to calculate SRPs in water versus SHE, and it is extremely important to have conversion factors enabling estimation of SRPs in nonaqueous solvents. A general equation relating E(theta) of a generic redox couple in water versus the SHE to the value of E(theta) in an organic solvent versus the aqueous saturated calomel electrode is reported. PMID:20496903

Isse, Abdirisak A; Gennaro, Armando

2010-06-17

179

Phenotypic identification of subclones in multiple myeloma with different chemoresistant, cytogenetic and clonogenic potential.  

PubMed

Knowledge about clonal diversity and selection is critical to understand multiple myeloma (MM) pathogenesis, chemoresistance and progression. If targeted therapy becomes reality, identification and monitoring of intraclonal plasma cell (PC) heterogeneity would become increasingly demanded. Here we investigated the kinetics of intraclonal heterogeneity among 116 MM patients using 23-marker multidimensional flow cytometry (MFC) and principal component analysis, at diagnosis and during minimal residual disease (MRD) monitoring. Distinct phenotypic subclones were observed in 35/116 (30%) newly diagnosed MM patients. In 10/35 patients, persistent MRD was detected after 9 induction cycles, and longitudinal comparison of patient-paired diagnostic vs MRD samples unraveled phenotypic clonal tiding after therapy in half (5/10) of the patients. After demonstrating selection of distinct phenotypic subsets by therapeutic pressure, we investigated whether distinct fluorescence-activated cell-sorted PC subclones had different clonogenic and cytogenetic profiles. In half (5/10) of the patients analyzed, distinct phenotypic subclones showed different clonogenic potential when co-cultured with stromal cells, and in 6/11 cases distinct phenotypic subclones displayed unique cytogenetic profiles by interphase fluorescence in situ hybridization, including selective del(17p13). Collectively, we unravel potential therapeutic selection of preexisting diagnostic phenotypic subclones during MRD monitoring; because phenotypically distinct PCs may show different clonogenic and cytogenetic profiles, identification and follow-up of unique phenotypic-genetic myeloma PC subclones may become relevant for tailored therapy.Leukemia advance online publication, 5 December 2014; doi:10.1038/leu.2014.321. PMID:25388955

Paíno, T; Paiva, B; Sayagués, J M; Mota, I; Carvalheiro, T; Corchete, L A; Aires-Mejía, I; Pérez, J J; Sanchez, M L; Barcena, P; Ocio, E M; San-Segundo, L; Sarasquete, M E; García-Sanz, R; Vidriales, M-B; Oriol, A; Hernández, M-T; Echeveste, M-A; Paiva, A; Blade, J; Lahuerta, J-J; Orfao, A; Mateos, M-V; Gutiérrez, N C; San-Miguel, J F

2014-11-12

180

Derivation of regional crop sequences as an indicator for potential GMO dispersal on large spatial scales  

Microsoft Academic Search

A methodological approach is presented which aims to visualise the constraints for crop sequence planning in agriculture in a regional, large-scale context. In particular, the relationship between the scope of oilseed rape cultivation and the overall regional cropping structure, the share of particular farm types and the interactions between single crops have been analysed. The identified constraints have been applied

Michael Glemnitz; Angelika Wurbs; Reinhold Roth

2011-01-01

181

Potential impacts of the Deepwater Horizon oil spill on large pelagic fishes  

Microsoft Academic Search

Biogeographical analyses provide insights on how the Deepwater Horizon oil spill impacted large pelagic fishes. We georeferenced historical ichthyoplankton surveys and published literature to map the spawning and larval areas of bluefin tuna, swordfish, blue marlin and whale shark sightings in the Gulf of Mexico with daily satellite-derived images detecting surface oil. The oil spill covered critical areas used by

Sarrah Frias-Torres; Charles R. Bostater Jr.

2011-01-01

182

Theory of small on large: Potential utility in computations of fluid–solid interactions in arteries  

Microsoft Academic Search

Recent advances in medical imaging, computational methods, and biomechanics promise to enable significant improvements in engineering-based decision making in vascular medicine, surgery, and training. To realize the potential of this approach, however, we must better synthesize the separate advances, particularly those in biofluid mechanics and arterial wall mechanics. In this paper, we describe a method for exploiting the typically small

S. Baek; R. L. Gleason; K. R. Rajagopal; J. D. Humphrey

2007-01-01

183

Large diffuse halos in time-dependent space-charge potentials with colored noise  

SciTech Connect

We explore the potential impact of colored noise on space-charge-induced halo formation. By coupling particle orbits to parametric resonance, colored noise due to space-charge fluctuations and/or imperfections in the beamline can eject particles to much larger amplitudes than would be inferred from parametric resonance alone.

Courtlandt Bohn and Ioannis V. Sideris

2003-05-22

184

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. PMID:23565037

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

2012-01-01

185

Sex differences in event-related potentials and attentional biases to emotional facial stimuli  

PubMed Central

Attentional processes play an important role in the processing of emotional information. Previous research reported attentional biases during stimulus processing in anxiety and depression. However, sex differences in the processing of emotional stimuli and higher prevalence rates of anxiety disorders among women, compared to men, suggest that attentional biases may also differ between the two sexes. The present study used a modified version of the dot probe task with happy, angry, and neutral facial stimuli to investigate the time course of attentional biases in healthy volunteers. Moreover, associations of attentional biases with alexithymia were examined on the behavioral and physiological level. Event-related potentials were measured while 21 participants (11 women) performed the task, utilizing also for the first time a difference wave approach in the analysis to highlight emotion-specific aspects. Women showed overall enhanced probe P1 amplitudes compared to men, in particular after rewarding facial stimuli. Using the difference wave approach, probe P1 amplitudes appeared specifically enhanced with regard to congruently presented happy facial stimuli among women, compared to men. Both methods yielded enhanced probe P1 amplitudes after presentation of the emotional stimulus in the left compared to the right visual hemifield. Probe P1 amplitudes correlated negatively with self-reported alexithymia, most of these correlations were only observable in women. Our results suggest that women orient their attention to a greater extent to facial stimuli than men and corroborate that alexithymia is a correlate of reduced emotional reactivity on a neuronal level. We recommend using a difference wave approach when addressing attentional processes of orientation and disengagement also in future studies. PMID:25566151

Pfabigan, Daniela M.; Lamplmayr-Kragl, Elisabeth; Pintzinger, Nina M.; Sailer, Uta; Tran, Ulrich S.

2014-01-01

186

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

187

Benthic ammonia oxidizers differ in community structure and biogeochemical potential across a riverine delta  

PubMed Central

Nitrogen pollution in coastal zones is a widespread issue, particularly in ecosystems with urban or agricultural watersheds. California's Sacramento-San Joaquin Delta, at the landward reaches of San Francisco Bay, is highly impacted by both agricultural runoff and sewage effluent, leading to chronically high nutrient loadings. In particular, the extensive discharge of ammonium into the Sacramento River has altered this ecosystem by vastly increasing ammonium concentrations and thus changing the stoichiometry of inorganic nitrogen stocks, with potential effects throughout the food web. This debate surrounding ammonium inputs highlights the importance of understanding the rates of, and controls on, nitrogen (N) cycling processes across the delta. To date, however, there has been little research examining N biogeochemistry or N-cycling microbial communities in this system. We report the first data on benthic ammonia-oxidizing microbial communities and potential nitrification rates for the Sacramento-San Joaquin Delta, focusing on the functional gene amoA (which codes for the ?-subunit of ammonia monooxygenase). There were stark regional differences in ammonia-oxidizing communities, with ammonia-oxidizing bacteria (AOB) outnumbering ammonia-oxidizing archaea (AOA) only in the ammonium-rich Sacramento River. High potential nitrification rates in the Sacramento River suggested these communities may be capable of oxidizing significant amounts of ammonium, compared to the San Joaquin River and the upper reaches of San Francisco Bay. Gene diversity also showed regional patterns, as well as phylogenetically unique ammonia oxidizers in the Sacramento River. The benthic ammonia oxidizers in this nutrient-rich aquatic ecosystem may be important players in its overall nutrient cycling, and their community structure and biogeochemical function appear related to nutrient loadings. Unraveling the microbial ecology and biogeochemistry of N cycling pathways, including benthic nitrification, is a critical step toward understanding how such ecosystems respond to the changing environmental conditions wrought by human development and climate change. PMID:25620958

Damashek, Julian; Smith, Jason M.; Mosier, Annika C.; Francis, Christopher A.

2015-01-01

188

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

189

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

190

Noise Reduction Potential of Large, Over-the-Wing Mounted, Advanced Turbofan Engines  

NASA Technical Reports Server (NTRS)

As we look to the future, increasingly stringent civilian aviation noise regulations will require the design and manufacture of extremely quiet commercial aircraft. Indeed, the noise goal for NASA's Aeronautics Enterprise calls for technologies that will help to provide a 20 EPNdB reduction relative to today's levels by the year 2022. Further, the large fan diameters of modem, increasingly higher bypass ratio engines pose a significant packaging and aircraft installation challenge. One design approach that addresses both of these challenges is to mount the engines above the wing. In addition to allowing the performance trend towards large, ultra high bypass ratio cycles to continue, this over-the-wing design is believed to offer noise shielding benefits to observers on the ground. This paper describes the analytical certification noise predictions of a notional, long haul, commercial quadjet transport with advanced, high bypass engines mounted above the wing.

Berton, Jeffrey J.

2000-01-01

191

Potential impacts of the Deepwater Horizon oil spill on large pelagic fishes  

NASA Astrophysics Data System (ADS)

Biogeographical analyses provide insights on how the Deepwater Horizon oil spill impacted large pelagic fishes. We georeferenced historical ichthyoplankton surveys and published literature to map the spawning and larval areas of bluefin tuna, swordfish, blue marlin and whale shark sightings in the Gulf of Mexico with daily satellite-derived images detecting surface oil. The oil spill covered critical areas used by large pelagic fishes. Surface oil was detected in 100% of the northernmost whale shark sightings, in 32.8 % of the bluefin tuna spawning area and 38 % of the blue marlin larval area. No surface oil was detected in the swordfish spawning and larval area. Our study likely underestimates the extend of the oil spill due to satellite sensors detecting only the upper euphotic zone and the use of dispersants altering crude oil density, but provides a previously unknown spatio-temporal analysis.

Frias-Torres, Sarrah; Bostater, Charles R., Jr.

2011-11-01

192

Psychopathy-related differences in selective attention are captured by an early event-related potential.  

PubMed

According to the response modulation model, the poorly regulated behavior of psychopathic individuals reflects a problem reallocating attention to process peripheral information while engaged in goal-directed behavior (Patterson & Newman, 1993). We evaluated this tenet using male prisoners and an early event-related potential component (P140) to index attentional processing. In all task conditions, participants viewed and categorized letter stimuli that could also be used to predict electric shocks. Instructions focused attention either on the threat-relevant dimension of the letters or an alternative, threat-irrelevant dimension. Offenders with high scores on Hare's (2003) Psychopathy Checklist-Revised displayed a larger P140 under alternative versus threat conditions. Beyond demonstrating psychopathy-related differences in early attention, these findings suggest that psychopathic individuals find it easier to ignore threat-related distractors when they are peripheral versus central to their goal-directed behavior. PMID:22452763

Baskin-Sommers, Arielle; Curtin, John J; Li, Wen; Newman, Joseph P

2012-10-01

193

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

194

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

195

Different potentiating effects of imidapril and enalapril on kaolin-induced writhing reaction in mice.  

PubMed

Effects of the angiotensin-converting enzyme (ACE) inhibitors, imidapril and enalapril, on kaolin-induced writhing reaction, which is believed to be caused by bradykinin (BK), were examined in mice. The number of writhes was increased significantly by 200 microg/kg of imidapril and by 100 and 200 microg/kg of enalapril. The intensity of writhing reaction was significantly suppressed by 1,000 nmol/kg of icatibant, a selective bradykinin B2 receptor antagonist, in the imidapril-, but not in the enalapril-treated groups. These results suggest that the potentiating effect of enalapril on kaolin-induced writhing reaction is greater than that of imidapril. This might depend on the difference of their inhibitory effects on BK degradation. PMID:11350012

Sakamoto, K; Sugimoto, K; Fujimura, A

2001-04-13

196

Comparison of triton bound state properties using different separable representations of realistic potentials  

E-print Network

The quality of two different separable expansion methods ({\\sl W} matrix and Ernst-Shakin-Thaler) is investigated. We compare the triton binding energies and components of the triton wave functions obtained in this way with the results of a direct two-dimensional treatment. The Paris, Bonn {\\sl A} and Bonn {\\sl B} potentials are employed as underlying two-body interactions, their total angular momenta being incorporated up to $j \\leq 2$. It is found that the most accurate results based on the Ernst-Shakin-Thaler method agree within 1.5% or better with the two-dimensional calculations, whereas the results for the {\\sl W}-matrix representation are less accurate.

W. Schadow; W. Sandhas; J. Haidenbauer; A. Nogga

1998-10-27

197

Termites: a potentially large source of atmospheric methane, carbon dioxide, and molecular hydrogen  

Microsoft Academic Search

Termites are emitting large quantities of CHâ, COâ, and Hâ into the atmosphere, especially in cleared tropical forest areas. Researchers estimate that these annual global emissions could amount to 0.3 trillion lb of CHâ, 11 trillion lb of COâ (more than twice the net global input from fossil-fuel combustion), and 0.4 trillion lb of Hâ. However, they stress that because

P. R. Zimmerman; J. P. Greenberg; S. O. Wandiga; P. J. Crutzen

1982-01-01

198

Kinetic Equivalence of Transmembrane pH and Electrical Potential Differences in ATP Synthesis*  

PubMed Central

ATP synthase is the key player of Mitchell's chemiosmotic theory, converting the energy of transmembrane proton flow into the high energy bond between ADP and phosphate. The proton motive force that drives this reaction consists of two components, the pH difference (?pH) across the membrane and transmembrane electrical potential (??). The two are considered thermodynamically equivalent, but kinetic equivalence in the actual ATP synthesis is not warranted, and previous experimental results vary. Here, we show that with the thermophilic Bacillus PS3 ATP synthase that lacks an inhibitory domain of the ? subunit, ?pH imposed by acid-base transition and ?? produced by valinomycin-mediated K+ diffusion potential contribute equally to the rate of ATP synthesis within the experimental range examined (?pH ?0.3 to 2.2, ?? ?30 to 140 mV, pH around the catalytic domain 8.0). Either ?pH or ?? alone can drive synthesis, even when the other slightly opposes. ?? was estimated from the Nernst equation, which appeared valid down to 1 mm K+ inside the proteoliposomes, due to careful removal of K+ from the lipid. PMID:22253434

Soga, Naoki; Kinosita, Kazuhiko; Yoshida, Masasuke; Suzuki, Toshiharu

2012-01-01

199

Different representations of potential and selected motor plans by distinct parietal areas.  

PubMed

Traditional theories have considered decision making as a separate neural process occurring before action planning. However, recent neurophysiological studies of spatial target selection have suggested that decision making and motor planning may be performed in an integrated manner. It was proposed that multiple potential plans are concurrently formed and the ultimately selected action simultaneously emerges within the same circuits (Shadlen and Newsome, 2001; Cisek and Kalaska, 2010). In the present study, we recorded from the parietal reach region (PRR) and dorsal area 5 (area 5d) in the posterior parietal cortex (PPC) while monkeys performed a nonspatial effector (saccade vs reach) choice task. The results show that PRR encodes potential and selected reach plans whereas area 5d encodes only selected reach plans, suggesting a serial visuomotor cortical circuitry for nonspatial effector decisions. Thus, there appears to be a different flow of processing for decisions and planning for spatial target selection, which is more integrated, and nonspatial effector decisions between eye and limb movements, which are more serial. PMID:22159124

Cui, He; Andersen, Richard A

2011-12-01

200

Kinetic equivalence of transmembrane pH and electrical potential differences in ATP synthesis.  

PubMed

ATP synthase is the key player of Mitchell's chemiosmotic theory, converting the energy of transmembrane proton flow into the high energy bond between ADP and phosphate. The proton motive force that drives this reaction consists of two components, the pH difference (?pH) across the membrane and transmembrane electrical potential (??). The two are considered thermodynamically equivalent, but kinetic equivalence in the actual ATP synthesis is not warranted, and previous experimental results vary. Here, we show that with the thermophilic Bacillus PS3 ATP synthase that lacks an inhibitory domain of the ? subunit, ?pH imposed by acid-base transition and ?? produced by valinomycin-mediated K(+) diffusion potential contribute equally to the rate of ATP synthesis within the experimental range examined (?pH -0.3 to 2.2, ?? -30 to 140 mV, pH around the catalytic domain 8.0). Either ?pH or ?? alone can drive synthesis, even when the other slightly opposes. ?? was estimated from the Nernst equation, which appeared valid down to 1 mm K(+) inside the proteoliposomes, due to careful removal of K(+) from the lipid. PMID:22253434

Soga, Naoki; Kinosita, Kazuhiko; Yoshida, Masasuke; Suzuki, Toshiharu

2012-03-16

201

Organic nanoparticles from different fuel blends: in vitro toxicity and inflammatory potential.  

PubMed

Despite the well-established link between particulate vehicle emissions and adverse health effects, the biological effects produced by ultrafine particles generated from fuel combustion need to be investigated. The biological impact of nano-sized organic carbon particles in the size range 3-7?nm, obtained from an engine fuelled with a standard diesel and four diesel fuels doped with additives of commercial interest is reported. Our data showed that the number of particles?different nano-sized organic carbon particles induce cytotoxic and proinflammatory effects on the in vitro systems A549 (epithelial cells) and BEAS-2B (bronchial cells). All the fuels tested are able to induce the release of proinflammatory interleukins 8 and 6; moreover, the IC50 values show that the additives can increase the toxic potential of particles 10 times. Further analyses are therefore needed to better define the potential impact of organic ultrafine particles on human health. PMID:25244046

Gualtieri, Maurizio; Capasso, Laura; D'Anna, Andrea; Camatini, Marina

2014-11-01

202

Large change in the predicted number of small halos due to a small amplitude oscillating inflaton potential  

SciTech Connect

A smooth inflaton potential is generally assumed when calculating the primordial power spectrum, implicitly assuming that a very small oscillation in the inflaton potential creates a negligible change in the predicted halo mass function. We show that this is not true. We find that a small oscillating perturbation in the inflaton potential in the slow-roll regime can alter significantly the predicted number of small halos. A class of models derived from supergravity theories gives rise to inflaton potentials with a large number of steps and many trans-Planckian effects may generate oscillations in the primordial power spectrum. The potentials we study are the simple quadratic (chaotic inflation) potential with superimposed small oscillations for small field values. Without leaving the slow-roll regime, we find that for a wide choice of parameters, the predicted number of halos change appreciably. For the oscillations beginning in the 10{sup 7}-10{sup 8}M{sub {center_dot}}range, for example, we find that only a 5% change in the amplitude of the chaotic potential causes a 50% suppression of the number of halos for masses between 10{sup 7}-10{sup 8}M{sub {center_dot}}and an increase in the number of halos for masses <10{sup 6}M{sub {center_dot}}by factors {approx}15-50. We suggest that this might be a solution to the problem of the lack of observed dwarf galaxies in the range 10{sup 7}-10{sup 8}M{sub {center_dot}.} This might also be a solution to the reionization problem where a very large number of Population III stars in low mass halos are required.

Rodrigues, Luiz Felippe S.; Opher, Reuven [Instituto de Astronomia Geofisica e Ciencias Atmosfericas, Universidade de Sao Paulo, Rua do Matao 1226, Cidade Universitaria, CEP 05508-900, Sao Paulo, SP (Brazil)

2010-07-15

203

Dispersal of large branchiopod cysts: Potential movement by wind from potholes on the Colorado Plateau  

USGS Publications Warehouse

Wind is suspected to be a primary dispersal mechanism for large branchiopod cysts on the Colorado Plateau. We used a wind tunnel to investigate wind velocities capable of moving pothole sediment and cysts from intact and disturbed surfaces. Material moved in the wind tunnel was trapped in filters; cysts were separated from sediment and counted. Undisturbed sediment moved at velocities as low as 5.9 m s-1 (12.3 miles h-1). A single all-terrain vehicle (ATV) track increased the sediment mass collected 10-fold, with particles moving at a wind velocity of only 4.2 m s-1 (8.7 miles h-1). Cysts were recovered from every wind tunnel trial. Measured wind velocities are representative of low-wind speeds measured near Moab, Utah. Wind can move large numbers of cysts to and from potholes on the Colorado Plateau. Our results indicate that large branchiopod cysts move across pothole basins at low-wind speeds; additional work is needed to establish velocities at which cysts move between potholes. ?? 2007 Springer Science+Business Media B.V.

Graham, T.B.; Wirth, D.

2008-01-01

204

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. PMID:24966558

Mojumder, Deb Kumar; Toledo, John De

2014-01-01

205

Comparison of the influence of halothane and isoflurane on airway transepithelial potential difference.  

PubMed

Bidirectional transport of Na+ and Cl- ions by the epithelium controls production and composition of airway surface liquid and airway transepithelial potential difference and in these ways supports mucociliary transport. Volatile anesthetics are able to inhibit epithelial ion transport processes when applied at high concentration and have been suggested to elicit depression of airway clearance and both these effects could be involved in postoperative pulmonary complications. The goal of these studies was to reveal possible influence of halothane and isoflurane at lower concentrations on electrogenic ion transport in airway epithelium. These studies were performed on the isolated rabbit tracheal wall mounted in the Ussing chamber. The reaction of the preparation to the gentle mechanical stimulation performed as a jet flux was examined without or in the presence of anesthetics at concentration equivalent to 0.5 minimal anesthetic concentration of volatile anesthetics in pulmonary alveoli (MAC), 1 MAC, 2 MAC, 5 MAC and 10 MAC. The volatile anesthetics at concentrations equivalent to 5 and 10 MAC affected airway transepithelial potential difference and influenced hyperpolarization or depolarization reactions which occurred after mechanical stimulation. The above effects were present when Na+ transport was inhibited by amiloride. The disturbed epithelial Cl- transport may be proposed as an explanation of the action of volatile anesthetics on electrophysiological parameters of the isolated tracheal wall although the influence of anesthetics on tachykinin secretion from C-fiber endings, which are present in the preparation, should also be taken into consideration. The long-lasting action (tens of minutes) of volatile anesthetics on the isolated tracheal wall should be also studied in the future as a model of airway reaction to prolonged volatile anesthesia. PMID:17085866

Smuszkiewicz, Piotr; Drobnik, Leon; Mieszkowski, Jan; Konikowski, Artur; Ho?y?ska, Iga; Kaczorowski, Piotr; Tyrakowski, Tomasz

2006-01-01

206

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. PMID:24855617

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

2014-01-01

207

The Flood Characteristics of Large U.K. Rivers: Potential Effects of Changing Climate and Land Use  

Microsoft Academic Search

A continuous flow simulation model(CLASSIC) has been used to assess the potential impactof climate and land use changes on the flood regimesof large U.K. catchments. Climate change scenarios,based on the HadCM2 experiments from the HadleyCentre, are applied to the Severn and Thames rivers.The analysis shows that, for the 2050s, the climatechange scenarios result in an increase in both thefrequency and

N. S. Reynard; C. Prudhomme; S. M. Crooks

2001-01-01

208

A refined quartic potential energy surface and large scale vibrational calculations for S0 thiophosgene.  

PubMed

In this work we present a full 6D quartic potential energy surface (PES) for S0 thiophosgene in curvilinear symmetrized bond-angle coordinates. The PES was refined starting from an ab initio field derived from acc-pVTZ basis set with CCSD(T) corrections for electron correlation. In the present calculations we used our variational method that was recently tested on formaldehyde and some of its isotopomers, along with additional improvements. The lower experimentally known vibrational levels for (35)Cl2CS were reproduced quite well in the calculations, which can be regarded as a test for the feasibility of the obtained quartic PES. PMID:25615683

Rashev, Svetoslav; Moule, David C

2015-04-01

209

NREL Confirms Large Potential for Grid Integration of Wind, Solar Power (Fact Sheet)  

SciTech Connect

To fully harvest the nation's bountiful wind and solar resources, it is critical to know how much electrical power from these renewable resources could be integrated reliably into the grid. To inform the discussion about the potential of such variable sources, the National Renewable Energy Laboratory (NREL) launched two key regional studies, examining the east and west sections of the U.S. power grid. The studies show that it is technically possible for U.S. power systems to integrate 20%-35% renewable electricity if infrastructure and operational improvements can be made.

Not Available

2011-10-01

210

Different Immune Regulatory Potential of Lactobacillus plantarum and Lactobacillus sakei Isolated from Kimchi.  

PubMed

It is known that lactic acid bacteria (LAB) have many beneficial health effects, including antioxidative activity and immune regulation. In this study, the immune regulatory effects of Lactobacillus sakei and Lactobacillus plantarum, which are found in different types of kimchi, were evaluated. L. sakei and its lipoteichoic acid (LTA) have greater immune stimulating potential in IL-12, IFN-?, and TNF-? production as compared with L. plantarum in an in vitro condition. On the other hand, L. plantarum is assumed to repress the Th1 immune response in murine experiments. After being injected with LPS, L. plantarum-fed mice maintained a healthier state, and the level of TNF-? in their blood was lower than in other bacterial strainfed mice and in the LPS-only control mice. Additionally, IL-12 production was significantly decreased and the production of IL-4 was greatly increased in the splenocytes from L. plantarum-fed mice. Further experiments revealed that the pre-injection of purified LTA from L. plantarum (pLTA), L. sakei (sLTA), and S. aureus (aLTA) decreased TNF-? and IL-4 production in LPS-injected mice. Mouse IL-12, however, was significantly increased by aLTA pre-injection. In conclusion, the L. sakei and L. plantarum strains have immune regulation effects, but the effects differ in cytokine production and the regulatory effects of the Th1/Th2 immune response. PMID:25112321

Hong, Yi-Fan; Kim, Hangeun; Kim, Hye Rim; Gim, Min Geun; Chung, Dae Kyun

2014-12-28

211

Characterization of the platelet-aggregating activity of cancer cells with different metastatic potential.  

PubMed

We studied the mechanisms of platelet activation by sublines exhibiting different metastatic potential of two murine experimental tumors: sublines M4 and M9 of the benzopyrene-induced mFS6 sarcoma and sublines B77-AA6 and B77-3T3 of RSV-transformed BALB/c 3T3 fibroblasts. The neoplastic cells of both models induced platelet aggregation, secretion and prostaglandin biosynthesis. In the first model but not in the second, all these processes correlated with the in vivo malignancy of cells. Pretreatment of B77-AA6 and B77-3T3 cells with apyrase significantly decreased platelet aggregation, while pretreatment of M4 cells was ineffective. However, pretreatment with trypsin or neuraminidase was effective in reducing platelet aggregation induced by M4 cells, but not that induced by any of the others; furthermore, phospholipase A2 reduced the platelet response by all sublines. Finally, platelet-activating activity was also found in the pellets obtained following centrifugation of culture media. These results suggest that platelets are stimulated by cancer cells through different mechanisms; platelet activation by a sialo-lipo-protein complex of the cellular membrane was found to be characteristic of the model in which the platelet-aggregating activity of neoplastic cells correlated with their in vivo metastatic behavior. PMID:3733262

Grignani, G; Pacchiarini, L; Almasio, P; Pagliarino, M; Gamba, G; Rizzo, S C; Ascari, E

1986-08-15

212

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

213

Visual and somatosensory event-related brain potentials in autistic children and three different control groups.  

PubMed

Event-related potentials (ERPs) to visual and somatosensory stimuli, generated during an oddball task, were obtained in a group of autistic children and 3 control groups (normal, attention-deficit, and dyslectic children, respectively). The task included the presentation of standard, deviant, and novel stimuli and had a (between-group) passive vs. active (counting) condition. Research questions were whether (a) autistic children differ from other children with respect to the processing of visual and/or somatosensory stimuli, as measured in the amplitude of the N1, mismatch activity, and P3, (b) autistic children specifically have problems in the processing of distal (visual) stimuli, compared to the processing of proximal (somatosensory) stimuli, and (c) autistic children have an atypical lateralization pattern of ERP activity. Only in the autistic group a task effect on the visual P2N2 (mismatch activity) and larger P3s to novels than to deviants were found, in both the visual and the somatosensory modality. There also was a smaller occipital P3 to visual standard stimuli in the passive condition in the autistic group than in 2 control groups. We concluded that autistics (a) differ from several other groups of children with respect to the visual P2N2 and the visual and somatosensory P3, (b) show abnormalities in the processing of both proximal and distal stimuli, and (c) show no indication of abnormal lateralization of ERPs. PMID:7514992

Kemner, C; Verbaten, M N; Cuperus, J M; Camfferman, G; Van Engeland, H

1994-05-01

214

Cross sections and rate constants for OH + H2 reaction on three different potential energy surfaces for ro-vibrationally excited reagents  

Microsoft Academic Search

A systematic study of the reagent ro-vibrational excitations in H2 + OH reaction is presented on three different potential energy surfaces using the multiconfiguration time-dependent Hartree method. An exact form of the kinetic energy operator including Coriolis coupling has been used. Coupled channel results on WDSE surface for vibrational excitation of H2 produce very large cross sections in accordance with

Sayak Bhattacharya; Aditya N. Panda; Hans-Dieter Meyer

2011-01-01

215

Plasma Simulation Using the Streamlined DARWIN Field Model with Applications to the Generation of Large Transient Potentials Within Anisotropic Plasmas.  

NASA Astrophysics Data System (ADS)

BEAGLE/GYMNOS, a two and one-half dimensional r-z particle-in-cell plasma simulation code using the Darwin limit of Maxwell's equations, is applied to the generation and control of transient potentials within anisotropic plasmas. The Darwin limit neglects the part of the displacement current which generates electromagnetic waves. Previous implementations of the Darwin model suffered from ambiguous boundary conditions needed in the vector decomposition of plasma source terms for the field equations. Use of the streamlined Darwin field model obviates the need for these troublesome vector decompositions, but results in a set of coupled partial differential equations. Applying the dynamic alternating-direction implicit (DADI) method to the coupled set of equations yields a fast and efficient field solution. Analysis of the DADI method as applied to coupled PDE's is presented, along with a comparison between DADI and the biconjugate gradient method. The code is applied to the generation and control of large electric potentials within mirror-confined plasmas. Suddenly applying a magnetic field at the midpoint of a mirror cell containing a low-density, high electron temperature plasma generates large potentials due to charge separation as the electrons respond to the mirror force. The resulting potential contours may prove useful for accelerating beams of heavy ions for inertial fusion applications. The results of simulations are presented and compared with those of analytic theory.

Larson, David Jeffrey

216

How large are cognitive gender differences? A meta-analysis using !w² and ^I d  

Microsoft Academic Search

E. E. Maccoby and C. N. Jacklin (1974) concluded that the following cognitive gender differences were well-established: verbal ability, quantitative ability, and visual–spatial ability. The present study applied meta-analysis techniques to studies cited by Maccoby and Jacklin, assessing the magnitude of gender differences using both |w–2 and d statistics. Results indicate that gender differences in all of these abilities were

Janet S. Hyde

1981-01-01

217

Habitat fragmentation in an urban environment: large and small fragments support different arthropod assemblages  

Microsoft Academic Search

We investigated the effects of fragmentation due to urbanisation on the species composition and functional roles of ants, beetles, spiders, flies and wasps. The study was conducted in 21 fragments of heath and woodland in south-eastern Australia classed as either ‘small’ (? 4 km2) or ‘large’ (? 80 km2). Arthropods were pitfall-trapped and identified to family or genus and morphospecies

Heloise Gibb; Dieter F. Hochuli

2002-01-01

218

Job-Entry Typewriting Speeds of Three Different Levels of Secretaries at a Large Public University.  

ERIC Educational Resources Information Center

A study examined the job-entry typewriting speeds of all 185 secretaries employed at East Tennessee State University, which was selected as an institution representative of large public universities with a college of medicine. The secretaries' scores on the timed typing test that they took at the time of their application for their present…

Loveday, Christine Hawk

219

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

220

Sex Differences in Intellectual Performance: Analysis of a Large Cohort of Competitive Chess Players  

Microsoft Academic Search

Only 1% of the world's chess grandmasters are women. This underrepresentation is unlikely to be caused by discrimination, because chess ratings objectively reflect competitive results. Using data on the ratings of more than 250,000 tournament players over 13 years, we investigated several potential explanations for the male domination of elite chess. We found that (a) the ratings of men are

Christopher F. Chabris; Mark E. Glickman

2006-01-01

221

Transcriptome Profile at Different Physiological Stages Reveals Potential Mode for Curly Fleece in Chinese Tan Sheep  

PubMed Central

Tan sheep (Ovis aries), a Chinese indigenous breed, has special curly fleece after birth, especially at one month old. However, this unique phenotype disappears gradually with age and the underlying reasons of trait evolvement are still unknown. In this study, skin transcriptome data was used to study this issue. In total 51,215 transcripts including described transcripts and transfrags were identified. Pathway analysis of the top 100 most highly expressed transcripts, which included TCHH and keratin gene family members, such as KRT25, KRT5, KRT71, KRT14 and others, showed pathways known to be relevant to hair/fleece development and function. Six hundred differentially expressed (DE) transcripts were detected at two different physiological ages (one-month-old with curly fleece and 48-month-old without curly fleece) and were categorized into three major functional groups: cellular component, molecular function, and biological process. The top six functional categories included cell, cell part, cellular process, binding, intracellular, metabolic process. The detected differentially expressed genes were particularly involved in signal, signal peptide, disulfide bond, glycoprotein and secreted terms, respectively. Further splicing isoform analysis showed that the metallothionein 3 isoform was up-regulated in Tan lamb skin, indicating that it may be related to the conformation of curly fleece in Chinese Tan lamb. The hair-related important differentially expressed genes (SPINK4, FGF21, ESR?, EphA3, NTNG1 and GPR110) were confirmed by qPCR analysis. We deduced that the differences existed in expressed transcripts, splice isoforms and GO categories between the two different physiological stages, which might constitute the major reasons for explaining the trait evolvement of curly fleece in Chinese Tan sheep. This study provides some clues for elucidating the molecular mechanism of fleece change with age in Chinese Tan sheep, as well as supplying some potential values for understanding human hair disorder and texture changes. PMID:23990983

Liu, Yufang; Xu, Qinqin; Zhang, Ming; Fang, Meiying

2013-01-01

222

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. PMID:24966965

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

2014-01-01

223

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

224

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

225

Termites: a potentially large source of atmospheric methane, carbon dioxide, and molecular hydrogen  

SciTech Connect

Termites are emitting large quantities of CH/sub 4/, CO/sub 2/, and H/sub 2/ into the atmosphere, especially in cleared tropical forest areas. Researchers estimate that these annual global emissions could amount to 0.3 trillion lb of CH/sub 4/, 11 trillion lb of CO/sub 2/ (more than twice the net global input from fossil-fuel combustion), and 0.4 trillion lb of H/sub 2/. However, they stress that because of many uncertainties, the acutal production of these gases could vary by a factor of two; i.e., methane production could range from 0.2 to 0.7 trillion lb. Occurring on about two-thirds of the earth's

Zimmerman, P.R.; Greenberg, J.P.; Wandiga, S.O.; Crutzen, P.J.

1982-11-01

226

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

227

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

228

Large-eddy simulation of turbulent combustion using different combustion models  

Microsoft Academic Search

The second-order moment (SOM) combustion model proposed by the present authors is compared with eddy-break-up (EBU) and presumed probability density function (PDF) combustion models in large-eddy simulation of jet diffusion combustion, swirling diffusion combustion and premixed combustion behind a bluff body. The statistical results for time-averaged and RMS fluctuation temperatures are validated by experimental results. It is seen that the

L. X. Zhou; L. Y. Hu; F. Wang

2008-01-01

229

Recruitment potential of two perennial grasses with different growth forms at a semiarid-arid transition zone  

Microsoft Academic Search

The objective of this study was to quantify differences in recruitment potential (seed production, seed presence in the soil) for two congeneric perennial grasses (Bouteloua gracilis, Bouteloua eriopoda (Poaceae)) that dominate adjacent arid and semiarid grassland biomes. It was hypothesized that these species have different recruitment strategies at the biome transition zone that are related to differences in their growth

DEBRA P. C. PETERS

2002-01-01

230

Alternative transcription start site selection leads to large differences in translation activity in yeast  

E-print Network

mRNA levels do not accurately predict protein levels in eukaryotic cells. To investigate contributions of 5? untranslated regions (5? UTRs) to mRNA-specific differences in translation, we determined the 5? UTR boundaries ...

Rojas-Duran, Maria F.

231

Contribution of gravitational potential energy differences to the global stress field  

NASA Astrophysics Data System (ADS)

Modelling the lithospheric stress field has proved to be an efficient means of determining the role of lithospheric versus sublithospheric buoyancies and also of constraining the driving forces behind plate tectonics. Both these sources of buoyancies are important in generating the lithospheric stress field. However, these sources and the contribution that they make are dependent on a number of variables, such as the role of lateral strength variation in the lithosphere, the reference level for computing the gravitational potential energy per unit area (GPE) of the lithosphere, and even the definition of deviatoric stress. For the mantle contribution, much depends on the mantle convection model, including the role of lateral and radial viscosity variations, the spatial distribution of density buoyancies, and the resolution of the convection model. GPE differences are influenced by both lithosphere density buoyancies and by radial basal tractions that produce dynamic topography. The global lithospheric stress field can thus be divided into (1) stresses associated with GPE differences (including the contribution from radial basal tractions) and (2) stresses associated with the contribution of horizontal basal tractions. In this paper, we investigate only the contribution of GPE differences, both with and without the inferred contribution of radial basal tractions. We use the Crust 2.0 model to compute GPE values and show that these GPE differences are not sufficient alone to match all the directions and relative magnitudes of principal strain rate axes, as inferred from the comparison of our depth integrated deviatoric stress tensor field with the velocity gradient tensor field within the Earth's plate boundary zones. We argue that GPE differences calibrate the absolute magnitudes of depth integrated deviatoric stresses within the lithosphere; shortcomings of this contribution in matching the stress indicators within the plate boundary zones can be corrected by considering the contribution from horizontal tractions associated with density buoyancy driven mantle convection. Deviatoric stress magnitudes arising from GPE differences are in the range of 1-4 TN m-1, a part of which is contributed by dynamic topography. The EGM96 geoid data set is also used as a rough proxy for GPE values in the lithosphere. However, GPE differences from the geoid fail to yield depth integrated deviatoric stresses that can provide a good match to the deformation indicators. GPE values inferred from the geoid have significant shortcomings when used on a global scale due to the role of dynamically support of topography. Another important factor in estimating the depth integrated deviatoric stresses is the use of the correct level of reference in calculating GPE. We also elucidate the importance of understanding the reference pressure for calculating deviatoric stress and show that overestimates of deviatoric stress may result from either simplified 2-D approximations of the thin sheet equations or the assumption that the mean stress is equal to the vertical stress.

Ghosh, Attreyee; Holt, William E.; Flesch, Lucy M.

2009-11-01

232

Utilizing Focus Groups with Potential Participants and Their Parents: An Approach to Inform Study Design in a Large Clinical Trial  

PubMed Central

Background In the recent literature, there has been some evidence that exposure of children to anesthetic procedures during the first two years of life may impair cognitive function and learning in later life. We planned a clinical study to quantify this risk, a study involving testing 1,000 children for neurodevelopmental deficits. As a part of this planning, we conducted focus groups involving potential participants and their parents to elicit information regarding three issues: communications with the community and potential participants, recruitment and consent processes, and the return of neurodevelopmental testing results. Methods Three focus groups were conducted with the parents of potential participants and one focus group was conducted with an 18-19 year old group; each group consisted of 6-10 participants. The moderated discussions had questions about recruitment, consenting issues, and expectations from the study about return of both overall trial findings and individual research test results. Results The focus group data gave us an insight on potential participants’ views on recruitment, consenting, communications about the study, and expectations about return of both overall trial findings and individual research test results. The concerns expressed were largely addressable. In addition, the concern we had about some parents enrolling their children in the study solely for the sake of getting their child's cognitive function results was dispelled. Conclusions We found that the individuals participating in our focus groups were generally enthusiastic about the large clinical study and could see the value in answering the study question. The data from the focus groups were used to inform changes to the recruitment and consent process. Focus group input was also instrumental in affirming the study design regarding return of results. Our experience suggests that the approach we used may serve as a model for other investigators to help inform the various elements of clinical study design, in particular the recruitment and consenting processes and expectations of potential participants regarding the return of individual research findings. PMID:24955380

Kadimpati, Sandeep; McCormick, Jennifer B; Chiu, Yichen; Parker, Ashley B.; Iftikhar, Aliya Z.; Flick, Randall P.; Warner, David O.

2014-01-01

233

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

234

Adult and cord blood endothelial progenitor cells have different gene expression profiles and immunogenic potential  

PubMed Central

Background Endothelial colony-forming cells (ECFC) are endowed with vascular regenerative ability in vivo and in vitro. In this study we compared the genotypic profile and the immunogenic potential of adult and cord blood ECFC, in order to explore the feasibility of using them as a cell therapy product. Materials and methods ECFC were obtained from cord blood samples not suitable for haematopoietic stem cell transplantation and from adult healthy blood donors after informed consent. Genotypes were analysed by commercially available microarray assays and results were confirmed by real-time polymerase chain reaction analysis. HLA antigen expression was evaluated by flow-cytometry. Immunogenic capacity was investigated by evaluating the activation of allogeneic lymphocytes and monocytes in co-cultures with ECFC. Results Microarray assays revealed that the genetic profile of cord blood and adult ECFC differed in about 20% of examined genes. We found that cord blood ECFC were characterised by lower pro-inflammatory and pro-thrombotic gene expression as compared to adult ECFC. Furthermore, whereas cord blood and adult ECFCs expressed similar amount of HLA molecules both at baseline and after incubation with ?-interferon, cord blood ECFC elicited a weaker expression of pro-inflammatory cytokine genes. Finally, we observed no differences in the amount of HLA antigens expressed among cord blood ECFC, adult ECFC and mesenchymal cells. Conclusions Our observations suggest that cord blood ECFC have a lower pro-inflammatory and pro-thrombotic profile than adult ECFC. These preliminary data offer level-headed evidence to use cord blood ECFC as a cell therapy product in vascular diseases. PMID:23867184

Nuzzolo, Eugenia R.; Capodimonti, Sara; Martini, Maurizio; Iachininoto, Maria G.; Bianchi, Maria; Cocomazzi, Alessandra; Zini, Gina; Leone, Giuseppe; Larocca, Luigi M.; Teofili, Luciana

2014-01-01

235

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

236

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. PMID:23593573

Naz, Rabia; Bano, Asghari

2012-01-01

237

An exploratory study of a finite difference method for calculating unsteady transonic potential flow  

NASA Technical Reports Server (NTRS)

A method for calculating transonic flow over steady and oscillating airfoils was developed by Isogai. The full potential equation is solved with a semi-implicit, time-marching, finite difference technique. Steady flow solutions are obtained from time asymptotic solutions for a steady airfoil. Corresponding oscillatory solutions are obtained by initiating an oscillation and marching in time for several cycles until a converged periodic solution is achieved. The method is described in general terms and results for the case of an airfoil with an oscillating flap are presented for Mach numbers 0.500 and 0.875. Although satisfactory results are obtained for some reduced frequencies, it is found that the numerical technique generates spurious oscillations in the indicial response functions and in the variation of the aerodynamic coefficients with reduced frequency. These oscillations are examined with a dynamic data reduction method to evaluate their effects and trends with reduced frequency and Mach number. Further development of the numerical method is needed to eliminate these oscillations.

Bennett, R. M.; Bland, S. R.

1979-01-01

238

The static properties and form factors of the deuteron using the different forms of the Wood-Saxon potential  

NASA Astrophysics Data System (ADS)

The basic properties and form factors of the deuteron system are investigated for the different forms of the Wood-Saxon potential. We have used the Nikiforov-Uvarov (NU) method for analytical solution of the radial Schrodinger equation. A comparison of the calculated values with experimental results are given. It is shown that the obtained results for the modified form of the Wood-Saxon potential are very close to the experimental results in comparison with other forms of the potential.

Rezaei, B.; Dashtimoghadam, A.

2014-09-01

239

Semiconducting large bandgap oxides as potential thermoelectric materials for high-temperature power generation?  

NASA Astrophysics Data System (ADS)

Semiconducting large bandgap oxides are considered as interesting candidates for high-temperature thermoelectric power generation (700-1,200 °C) due to their stability, lack of toxicity and low cost, but so far they have not reached sufficient performance for extended application. In this review, we summarize recent progress on thermoelectric oxides, analyze concepts for tuning semiconductor thermoelectric properties with view of their applicability to oxides and determine key drivers and limitations for electrical and thermal transport properties in oxides based on our own experimental work and literature results. For our experimental assessment, we have selected representative multicomponent oxides that range from materials with highly symmetric crystal structure (SrTiO3 perovskite) over oxides with large densities of planar crystallographic defects (Ti n O2 n-1 Magnéli phases with a single type of shear plane, NbO x block structures with intersecting shear planes and WO3- x with more defective block and channel structures) to layered superstructures (Ca3Co4O9 and double perovskites) and also include a wide range of their composites with a variety of second phases. Crystallographic or microstructural features of these oxides are in 0.3-2 nm size range, so that oxide phonons can efficiently interact with them. We explore in our experiments the effects of doping, grain size, crystallographic defects, superstructures, second phases, texturing and (to a limited extend) processing on electric conductivity, Seebeck coefficient, thermal conductivity and figure of merit. Jonker and lattice-versus-electrical conductivity plots are used to compare specific materials and material families and extract levers for future improvement of oxide thermoelectrics. We show in our work that oxygen vacancy doping (reduction) is a more powerful driver for improving the power factor for SrTiO3, TiO2 and NbO x than heterovalent doping. Based on our Seebeck-conductivity plots, we derived a set of highest achievable power factors. We met these best values in our own experiments for our titanium oxide- and niobium oxide-based materials. For strontium titanate-based materials, the estimated highest power factor was not reached; further material improvement is possible and can be reached for materials with higher carrier densities. Our results show that periodic crystallographic defects and superstructures are most efficient in reducing the lattice thermal conductivity in oxides, followed by hetero- and homovalent doping. Due to the small phonon mean free path in oxides, grain boundary scattering in nanoceramics or materials with nanodispersions is much less efficient. We investigated the impact of texturing in Ca3Co4O9 ceramics on thermoelectric performance; we did not find any improvement in the overall in-plane performance of a textured ceramic compared to the corresponding random ceramic.

Backhaus-Ricoult, M.; Rustad, J.; Moore, L.; Smith, C.; Brown, J.

2014-08-01

240

Do Large Earthquakes Penetrate below the Seismogenic Zone? Potential Clues from Microseismicity  

NASA Astrophysics Data System (ADS)

It is typically assumed that slip in large earthquakes is confined within the seismogenic zone - often defined by the extent of the background seismicity - with regions below creeping. In terms of rate-and-state friction properties, the locked seismogenic zone and the deeper creeping fault extensions are velocity-weakening (VW) and velocity-strengthening (VS), respectively. Recently, it has been hypothesized that earthquake rupture could penetrate into the deeper creeping regions (Shaw and Wesnousky, BSSA, 2008), and yet it is difficult to detect the deep slip due to limited resolution of source inversions with depth. We hypothesize that absence of concentrated microseismicity at the bottom of the seismogenic zone may point to the existence of deep-penetrating earthquake ruptures. The creeping-locked boundary creates strain and stress concentrations. If it is at the bottom of the VW region, which supports earthquake nucleation, microseismicity should persistently occur at the bottom of the seismogenic zone. Such behavior has been observed on the Parkfield segment of the San Andreas Fault (SAF) and the Calaveras fault. However, such microseismicity would be inhibited if dynamic earthquake rupture penetrates substantially below the VW/VS transition, which would drop stress in the ruptured VS areas, making them effectively locked. Hence the creeping-locked boundary, with its stress concentration, would be located within the VS area, where earthquake nucleation is inhibited. Indeed, microseismicity concentration at the bottom of the seismogenic zone is not observed for several faults that hosted major earthquakes, such as the Carizzo segment of the SAF (the site of 1857 Mw 7.9 Fort Tejon earthquake) and Palu-Lake-Hazar segment of the Eastern Anatolian Fault. We confirm this hypothesis by simulating earthquake sequences and aseismic slip in 3D fault models (Lapusta and Liu, 2009; Noda and Lapusta, 2010). The fault is governed by rate-and-state friction laws, with a VW region surrounded by VS areas. At the bottom of the VW region, patches of smaller nucleation sizes simulate fault heterogeneity that could lead to microseismicity. On part of the fault, thermally-induced pore fluid pressurization (TP) is effective, leading to enhanced coseismic weakening. The possibility of coseismic weakening of VS areas has been suggested in recent studies (e.g., Rice and Platt, AGU, 2011; Noda and Lapusta, AGU, 2011). In the case where efficient TP is restricted to the VW zone, model-spanning earthquakes arrest quickly in the VS areas, and the creeping-locked boundary reaches the bottom of the VW region early in the earthquake cycle, producing microseismicity. In contrast, if efficient TP extends deeper (5 km), ruptures activate coseismic weakening in the VS areas, penetrating much deeper. The creeping-locked boundary, while moving updip with time, is below the VW area throughout the interseismic period, producing no microseismicity. Hence, the absence of concentrated microseismicity at the bottom of the seismogenic zone may point to penetration of large earthquakes below seismogenic zones. The argument is strongest under the assumption of localized shear zones extending below the so-called brittle-ductile transition, which is supported by frictional postseismic slip and seismic tremor at the deeper fault extensions (e.g., Bruhat et al., JGR, 2011; Shelly, 2010)

Jiang, J.; Lapusta, N.

2012-12-01

241

Multicomponent interparticle-potential lattice Boltzmann model for fluids with large viscosity ratios.  

PubMed

This work focuses on an improved multicomponent interparticle-potential lattice Boltzmann model. The model results in viscosity-independent equilibrium densities and is capable of simulating kinematic viscosity ratios greater than 1000. External forces are incorporated into the discrete Boltzmann equation, rather than through an equilibrium velocity shift as in the original Shan and Chen (hereafter, SC) model. The model also requires the derivation of a momentum conserving effective velocity, which is substituted into the equilibrium distribution function and applies to both the single- and multiple-relaxation-time formulations. Additionally, higher-order isotropy is used in the calculation of the fluid-fluid interaction forces to reduce the magnitude of spurious currents (i.e., numerical errors) in the vicinity of interfaces. First, we compare the model to the SC model for static bubble simulations. We demonstrate that the model results in viscosity-independent equilibrium bubble densities for a wide range of kinematic viscosities, which is not the case for the SC model. Furthermore, we show that the model is capable of simulating stable bubbles for kinematic viscosity ratios greater than 1000 (when higher-order isotropy is used), whereas the SC model is known to be limited to kinematic viscosity ratios on the order of 10. Next we verify the model for surface tension via Laplace's law and show that the model results in the same surface tension values for a range of kinematic viscosities and kinematic viscosity ratios of 10, 100, and 1000. The model is also verified for layered cocurrent flow though parallel plates. We show that the simulated velocity profiles preserve continuity at the interface for kinematic viscosity ratios ranging from 0.001 to 1000 and that the model accurately predicts nonwetting and wetting phase relative permeability for kinematic viscosity ratios of 0.01 to 100. PMID:23031047

Porter, Mark L; Coon, E T; Kang, Q; Moulton, J D; Carey, J W

2012-09-01

242

Multicomponent interparticle-potential lattice Boltzmann model for fluids with large viscosity ratios  

NASA Astrophysics Data System (ADS)

This work focuses on an improved multicomponent interparticle-potential lattice Boltzmann model. The model results in viscosity-independent equilibrium densities and is capable of simulating kinematic viscosity ratios greater than 1000. External forces are incorporated into the discrete Boltzmann equation, rather than through an equilibrium velocity shift as in the original Shan and Chen (hereafter, SC) model. The model also requires the derivation of a momentum conserving effective velocity, which is substituted into the equilibrium distribution function and applies to both the single- and multiple-relaxation-time formulations. Additionally, higher-order isotropy is used in the calculation of the fluid-fluid interaction forces to reduce the magnitude of spurious currents (i.e., numerical errors) in the vicinity of interfaces. First, we compare the model to the SC model for static bubble simulations. We demonstrate that the model results in viscosity-independent equilibrium bubble densities for a wide range of kinematic viscosities, which is not the case for the SC model. Furthermore, we show that the model is capable of simulating stable bubbles for kinematic viscosity ratios greater than 1000 (when higher-order isotropy is used), whereas the SC model is known to be limited to kinematic viscosity ratios on the order of 10. Next we verify the model for surface tension via Laplace's law and show that the model results in the same surface tension values for a range of kinematic viscosities and kinematic viscosity ratios of 10, 100, and 1000. The model is also verified for layered cocurrent flow though parallel plates. We show that the simulated velocity profiles preserve continuity at the interface for kinematic viscosity ratios ranging from 0.001 to 1000 and that the model accurately predicts nonwetting and wetting phase relative permeability for kinematic viscosity ratios of 0.01 to 100.

Porter, Mark L.; Coon, E. T.; Kang, Q.; Moulton, J. D.; Carey, J. W.

2012-09-01

243

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. PMID:24587155

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

2014-01-01

244

Genome sequencing of Listeria monocytogenes "Quargel" listeriosis outbreak strains reveals two different strains with distinct in vitro virulence potential.  

PubMed

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. PMID:24587155

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

2014-01-01

245

Racial differences in obesity measures and risk of colorectal adenomas in a large screening population.  

PubMed

Obesity is an important risk factor for colorectal neoplasia; however, little research exists on racial differences in obesity measures [body mass index (BMI), waist circumference (WC), and waist-hip-ratio (WHR)] associated with adenoma. We used data from the Diet and Health Studies, Phases III-V to examine differences in the contribution of obesity measures to adenoma risk by race. The sample consisted of 2184 patients (1806 white, 378 African American) undergoing outpatient colonoscopy for average risk screening. Covariates included demographics, health history, and validated measures of diet and physical activity. Among whites, BMI [overweight: odds ratio (OR) = 1.31, 95% confidence interval (CI), 1.00-1.71; obese: OR = 1.89, 95% CI, 1.41-2.56), WC (OR = 1.47, 95% CI, 1.09-1.99), and WHR (OR = 1.60, 95% CI, 1.24-2.06) were associated with adenomas. BMI was not associated with adenomas in African Americans. Although the CIs were wide, the point estimates for WHR (OR = 1.07, 95% CI, 0.51-2.22) and WC (OR = 1.04, 95% CI, 0.56-1.92) were slightly elevated above the null. BMI was associated with adenomas only among whites, whereas WHR and WC appeared to be important risk factors among both races. Racial differences in adenoma risk may be due to differences in body shape and weight and/or fat distribution. PMID:25425186

Murphy, Caitlin C; Martin, Christopher F; Sandler, Robert S

2015-01-01

246

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

247

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

PubMed Central

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

248

Potential of a Future Large Aperture UVOIR Space Observatory for Breakthrough Observations of Star and Planet Formation  

NASA Astrophysics Data System (ADS)

A future large aperture space observatory operating from the UV to the near-infrared with a diameter between 10 and 15 meters will provide a unique opportunity for observations of star and planet formation, from nearby moving groups and associations to star formation in galaxies in the local universe. Our newly formed working group will examine the unique opportunities that such a telescope will give observers in a post-JWST/WFIRST-AFTA era that includes extremely large ground-based observatories such as the TMT, E-ELT, ALMA, and the VLTI. Given a potential suite of instruments for this observatory we will discuss some of the key areas of star and planet formation science where breakthroughs might occur.

Danchi, William C.; Grady, Carol A.; Padgett, Deborah

2015-01-01

249

Light baryon masses in different large-N{sub c} limits  

SciTech Connect

We investigate the behavior of light baryon masses in three inequivalent large-N{sub c} limits: 't Hooft, QCD{sub AS} and Corrigan-Ramond. Our framework is a constituent quark model with relativistic-type kinetic energy, stringlike confinement, and one-gluon-exchange term, thus leading to well-defined results even for massless quarks. We analytically prove that the light baryon masses scale as N{sub c}, N{sub c}{sup 2}, and 1 in the 't Hooft, QCD{sub AS} and Corrigan-Ramond limits, respectively. Those results confirm previous ones obtained by using either diagrammatic methods or constituent approaches, mostly valid for heavy quarks.

Buisseret, Fabien; Semay, Claude [Service de Physique Nucleaire et Subnucleaire, Universite de Mons-UMONS, Academie universitaire Wallonie-Bruxelles, Place du Parc 20, B-7000 Mons (Belgium)

2010-09-01

250

Laminar flow of a gas in a tube with large temperature differences  

NASA Astrophysics Data System (ADS)

The laminar low Mach number flow of a gas in a tube is analyzed for very small and very large values of the inlet-to-wall temperature ratio. When this ratio tends to zero, pressure forces confine the cold gas to a thin core around the axis of the tube. This core is neatly bounded by an ablation front that consumes it at a finite distance from the tube inlet. When the temperature ratio tends to infinity, the temperature of the gas increases smoothly from the wall to the axis of the tube and the shear stress and heat flux are positive at the wall despite the fact that the viscosity and thermal conductivity of the gas scaled with their inlet values tend to zero at the wall.

Higuera, F. J.

2011-12-01

251

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

252

Integral representation of voltage in half-plane conductor with embedded crack by D.C. potential difference method  

NASA Astrophysics Data System (ADS)

Non destructive testing (NDT) has been used to ensure safety in public structure and public space. D.C. potential difference method, one of the NDT, is used to detect a crack in a conductive material. In this paper we obtain an exact solution for model equation for D.C. potential difference method, which is the Laplace equation with an embedded crack in two dimensional half-space by using singular integral equation and angular potential. The solution can be computed and is useful for actual investigation of a crack.

Akira, Sasamoto; Krutitskii, P. A.

2013-10-01

253

Plasma variables, meat quality, and glycolytic potential in broilers stunned with different carbon dioxide concentrations.  

PubMed

This study aimed to investigate the effects of different CO(2) concentrations on blood variables, glycolytic potential (GP), and meat quality of hot-boned muscles in broilers. Thirty broilers were exposed to one of the following 5 gas mixtures for 90 s: 40% CO(2) + 30% O(2) + N(2) (control), 30% CO(2) + 21% O(2) + N(2) (G30%), 40% CO(2) + 21% O(2) + N(2) (G40%), 50% CO(2) + 21% O(2) + N(2) (G50%), and 60% CO(2) + 21% O(2) + N(2) (G60%). Samples were taken from the pectoralis major (PM), musculus iliofibularis (MI), and tibialis anterior muscles 45 min postmortem. The ultimate pH in both the PM (vs. G30% and G40%) and MI (vs. G40%) was decreased with G60% (P < 0.05), whereas drip loss in the PM (vs. G30%, P = 0.01) was increased with G60%. Drip loss in the MI (vs. control and G30%, P < 0.01) was increased with G50%. Lightness after 24 h in PM (vs. G30% and G40%, P < 0.01) was increased with G50%. In MI, lightness after 24 h was slightly decreased with G40% compared with the control (P < 0.10). The GP value in the PM was lower in the G30% and G40% than in G60% (P < 0.05), and the GP value in the tibialis anterior was the lowest in G30% (P < 0.01). Plasma corticosterone, plasma glucose, and meat quality (pH, lightness, redness, yellowness) 45 min postmortem were not affected by CO(2) levels (P > 0.05). In conclusion, stunning broilers with low CO(2) levels (30 and 40%) improved meat quality but had no advantage in animal welfare compared with high CO(2) levels (50 and 60%). PMID:21753222

Xu, L; Ji, F; Yue, H Y; Wu, S G; Zhang, H J; Zhang, L; Qi, G H

2011-08-01

254

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

255

Comparing the rehydration potential of different milk-based drinks to a carbohydrate-electrolyte beverage.  

PubMed

The aim of this study was to compare the rehydration potential of a carbohydrate-electrolyte beverage with several varieties of milk following exercise-induced fluid losses. Fifteen male participants (age 24.9 ± 5.5 years, height 179.3 ± 4.9 cm, body mass 75.8 ± 6.6 kg (mean ± SD)) lost 2.0% ± 0.2% body mass through intermittent cycling before consuming a different beverage on 4 separate occasions. Drinks included cow's milk (286 kJ·100 mL(-1)), soy milk (273 kJ·100 mL(-1)), a milk-based liquid meal supplement (Sustagen Sport (Nestle); 417 kJ·100 mL(-1)), and a sports drink (Powerade (Coca Cola Ltd); 129 kJ·100 mL(-1)). Beverages were consumed over 1 h in volumes equivalent to 150% of body mass loss. Body mass, blood and urine samples, and measures of gastrointestinal tolerance were obtained before and hourly for 4 h after beverage consumption. Net body mass at the conclusion of each trial was significantly less with Powerade (-1.37 ± 0.3 kg) than with cow's milk (-0.92 ± 0.48 kg), soy milk (-0.78 ± 0.37 kg), and Sustagen Sport (-0.48 ± 0.39 kg). Net body mass was also significantly greater for Sustagen Sport compared with cow's milk trials, but not soy milk. Upon completion of trials, the percentage of beverage retained was Sustagen Sport 65.1% ± 14.7%, soy milk 46.9% ± 19.9%, cow's milk 40.0% ± 24.9%, and Powerade 16.6% ± 16.5%. Changes in plasma volume and electrolytes were unaffected by drink treatment. Subjective ratings of bloating and fullness were higher during all milk trials compared with Powerade whereas ratings of overall thirst were not different between beverages. Milk-based drinks are more effective rehydration options compared with traditional sports drinks. The additional energy, protein, and sodium in a milk-based liquid meal supplement facilitate superior fluid recovery following exercise. PMID:25315686

Desbrow, Ben; Jansen, Sarah; Barrett, Abby; Leveritt, Michael D; Irwin, Christopher

2014-12-01

256

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

257

Intraurban Differences in the Use of Ambulatory Health Services in a Large Brazilian City  

PubMed Central

A major goal of health systems is to reduce inequities in access to services, that is, to ensure that health care is provided based on health needs rather than social or economic factors. This study aims to identify the determinants of health services utilization among adults in a large Brazilian city and intraurban disparities in health care use. We combine household survey data with census-derived classification of social vulnerability of each household’s census tract. The dependent variable was utilization of physician services in the prior 12 months, and the independent variables included predisposing factors, health needs, enabling factors, and context. Prevalence ratios and 95% confidence intervals were estimated by the Hurdle regression model, which combined Poisson regression analysis of factors associated with any doctor visits (dichotomous variable) and zero-truncated negative binomial regression for the analysis of factors associated with the number of visits among those who had at least one. Results indicate that the use of health services was greater among women and increased with age, and was determined primarily by health needs and whether the individual had a regular doctor, even among those living in areas of the city with the worst socio-environmental indicators. The experience of Belo Horizonte may have implications for other world cities, particularly in the development and use of a comprehensive index to identify populations at risk and in order to guide expansion of primary health care services as a means of enhancing equity in health. PMID:21104332

Lima-Costa, Maria Fernanda; Proietti, Fernando Augusto; Cesar, Cibele C.; Macinko, James

2010-01-01

258

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

259

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

260

Sensitivity tests on the criterion of potential vorticity index for discriminating the location of ozone sources and sinks over large continental areas  

NASA Astrophysics Data System (ADS)

This paper presents the results of a sensitivity analysis of a statistical-dynamic model (ISOGASP, standing for Identification of SOurces of greenhouse GAS Plus), developed by our research group to reconstruct 3D concentration patterns of greenhouse gases in large and deep atmospheric regions over continental or oceanic areas and extending vertically from the lower troposphere to the lower stratosphere. The results of this analysis have shown the ability of the ISOGASP model to discriminate the locations of ozone sources, according to the geographical distribution patterns of atmospheric O3 concentration inside a limited number of atmospheric layers at different heights above sea level, reconstructed through the method of backward trajectories simulating the travel of air parcels from each different layer to the receptor points at their own height. The potential vorticity index has been used to discriminate the sub-sets of trajectories belonging to stratosphere or troposphere.

Cacòpardo, T.; Ferrarese, S.; Longhetto, A.; Cassardo, C.

2004-03-01

261

Calculation of free-energy differences and potentials of mean force by a multi-energy gap method  

E-print Network

Calculation of free-energy differences and potentials of mean force by a multi-energy gap method the convergence of free-energy calculations. It introduces a bias factor in Monte Carlo simulations or.e., the difference in energy function between two states, and is therefore specifically designed for calculating free-energy

Weston, Ken

262

Uncertainty of SWAT model at different DEM resolutions in a large mountainous watershed.  

PubMed

The objective of this study was to enhance understanding of the sensitivity of the SWAT model to the resolutions of Digital Elevation Models (DEMs) based on the analysis of multiple evaluation indicators. The Xiangxi River, a large tributary of Three Gorges Reservoir in China, was selected as the study area. A range of 17 DEM spatial resolutions, from 30 to 1000 m, was examined, and the annual and monthly model outputs based on each resolution were compared. The following results were obtained: (i) sediment yield was greatly affected by DEM resolution; (ii) the prediction of dissolved oxygen load was significantly affected by DEM resolutions coarser than 500 m; (iii) Total Nitrogen (TN) load was not greatly affected by the DEM resolution; (iv) Nitrate Nitrogen (NO?-N) and Total Phosphorus (TP) loads were slightly affected by the DEM resolution; and (v) flow and Ammonia Nitrogen (NH?-N) load were essentially unaffected by the DEM resolution. The flow and dissolved oxygen load decreased more significantly in the dry season than in the wet and normal seasons. Excluding flow and dissolved oxygen, the uncertainties of the other Hydrology/Non-point Source (H/NPS) pollution indicators were greater in the wet season than in the dry and normal seasons. Considering the temporal distribution uncertainties, the optimal DEM resolutions for flow was 30-200 m, for sediment and TP was 30-100 m, for dissolved oxygen and NO?-N was 30-300 m, for NH?-N was 30 to 70 m and for TN was 30-150 m. PMID:24509347

Zhang, Peipei; Liu, Ruimin; Bao, Yimeng; Wang, Jiawei; Yu, Wenwen; Shen, Zhenyao

2014-04-15

263

Differences in Human Cortical Gene Expression Match the Temporal Properties of Large-Scale Functional Networks  

PubMed Central

We explore the relationships between the cortex functional organization and genetic expression (as provided by the Allen Human Brain Atlas). Previous work suggests that functional cortical networks (resting state and task based) are organized as two large networks (differentiated by their preferred information processing mode) shaped like two rings. The first ring–Visual-Sensorimotor-Auditory (VSA)–comprises visual, auditory, somatosensory, and motor cortices that process real time world interactions. The second ring–Parieto-Temporo-Frontal (PTF)–comprises parietal, temporal, and frontal regions with networks dedicated to cognitive functions, emotions, biological needs, and internally driven rhythms. We found–with correspondence analysis–that the patterns of expression of the 938 genes most differentially expressed across the cortex organized the cortex into two sets of regions that match the two rings. We confirmed this result using discriminant correspondence analysis by showing that the genetic profiles of cortical regions can reliably predict to what ring these regions belong. We found that several of the proteins–coded by genes that most differentiate the rings–were involved in neuronal information processing such as ionic channels and neurotransmitter release. The systematic study of families of genes revealed specific proteins within families preferentially expressed in each ring. The results showed strong congruence between the preferential expression of subsets of genes, temporal properties of the proteins they code, and the preferred processing modes of the rings. Ionic channels and release-related proteins more expressed in the VSA ring favor temporal precision of fast evoked neural transmission (Sodium channels SCNA1, SCNB1 potassium channel KCNA1, calcium channel CACNA2D2, Synaptotagmin SYT2, Complexin CPLX1, Synaptobrevin VAMP1). Conversely, genes expressed in the PTF ring favor slower, sustained, or rhythmic activation (Sodium channels SCNA3, SCNB3, SCN9A potassium channels KCNF1, KCNG1) and facilitate spontaneous transmitter release (calcium channel CACNA1H, Synaptotagmins SYT5, Complexin CPLX3, and synaptobrevin VAMP2). PMID:25546015

Cioli, Claudia; Abdi, Hervé; Beaton, Derek; Burnod, Yves; Mesmoudi, Salma

2014-01-01

264

Potential impact of atmospheric N deposition on soil N2O emission varies with different soil N regimes  

NASA Astrophysics Data System (ADS)

Future increases in nitrogen (N) deposition has the potential to change belowground nutrient dynamics, especially N cycle, and thereby can alter the soil-atmosphere exchange of nitrous oxide (N2O) which is one of the major greenhouse gases. Moreover, we considered that their effect on soil N2O emission varies with different soil N levels because N2O is a by-product of the biological nitrification process in aerobic soil environments and of the biological denitrification process in anaerobic soil environments. To understand the changes in soil N2O flux under different soil N, we carried out simulated N addition experiment in three-year-old hybrid larch F1 (F1: Larix gmelinii var. japonica × Larix kaempferi) plantation during two growing seasons 2008 - 2009. The hybrid larch F1 was developed to make up for several problems of larch species, e.g. a high susceptibility to disease or grazing damage by insects and fungi, and a large number of this seedlings are planted recently in northern Japan. Based on soil analysis, we selected two sites which have different soil N concentration, i.e. low-N and high-N concentrations. Nitrogen input was initiated at the onset of our experiment, and included four treatments with four replications: Low-N soil + Zero-N control, Low-N soil + 50 kg-N addition, High-N soil + Zero-N control and High-N soil + 50 kg-N addition. The N was added as ammonium nitrate (NH4NO3) solution distributed in four occasions during each growing season. Gas and soil samples were taken from each plot on ten occasions at a time during each growing season. Collected N2O concentrations were determined by a gas chromatograph (GC-14B; Shimadzu, Kyoto, Japan) equipped with an electron capture detector, while total-N and inorganic-N concentrations were obtained by a NC analyzer (Sumigraph NC-1000; Sumica Chemical Analysis Service Ltd., Osaka, Japan) and an auto analyzer (AACS-4; BL-TEC Inc., Osaka, Japan), respectively. Before the N addition, initial total-N in High-N soil was almost two times higher than that of Low-N soil, but there were no significant differences in physical soil properties among four treatments, e.g. bulk density and water-filled pore space. During the measurement period, N addition increased NH4-N and NO3-N concentrations (P < 0.01), and therefore stimulated soil N2O emissions from 50 kg-N addition plots in both soil N regimes (P < 0.05). Furthermore, increased levels of soil N2O flux in High-N soil were higher than that of Low-N soil (P < 0.001). In this study, we found a positive spatial relationship between soil N2O emission and NO3-N concentration (R2 = 0.80, P < 0.0001). Overall, N addition induced emission in High-N soil was equivalent to 1.66% of the applied N. This value is over the IPCC 1.25% default value, but the loss of 0.69% in Low-N soil is considerably lower than the IPCC mean default value. In conclusion, our results suggest that soil N2O emission seems to largely depend on whether the ecosystem N limited or not at the time of N inputs. Nitrogen cycling in forest ecosystems, which already exhibits large N2O emission, responded strongly to the added N, where as an ecosystem that has been limited by N uses up the added N rapidly and soil N2O emission was elevated only for a short term.

Kim, Y.; Yi, M.; Koike, T.

2011-12-01

265

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

266

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

267

Altitude distribution of the auroral acceleration potential determined from cluster satellite data at different heights.  

PubMed

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(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. PMID:21405403

Marklund, Göran T; Sadeghi, Soheil; Karlsson, Tomas; Lindqvist, Per-Arne; Nilsson, Hans; Forsyth, Colin; Fazakerley, Andrew; Lucek, Elizabeth A; Pickett, Jolene

2011-02-01

268

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. PMID:24817872

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

2014-01-01

269

Resolving the cause of large differences between deglacial benthic foraminifera radiocarbon measurements in Santa Barbara Basin  

NASA Astrophysics Data System (ADS)

To better understand the deglacial upwelling pattern in the east Pacific, we have made radiocarbon (14C) measurements on benthic foraminifera and macrofauna from a 3.5 m long interval in ODP Core 893A from Santa Barbara Basin, California, representing early deglaciation. This work serves to investigate the source of apparent disagreement between radiocarbon data sets from Leibnitz Laboratory, Kiel University (Kiel) and Carbon Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory (LLNL). These data sets are based on measurements of mixed benthic and mixed planktonic foraminifera. Interlaboratory 14C results are similar for the planktonic foraminiferal analyses; however, Kiel measurements on mixed benthic foraminifera are much older than mixed benthic measurements from equivalent depths measured at LLNL. Our new results show distinct 14C differences between taxa, with Pyrgo sp. giving ages consistently older than Kiel measurements on mixed benthic taxa, while ages for Nonionellina sp., Buliminella sp., Uvigerina sp., and benthic macrofauna were much younger, even younger than the LLNL mixed benthic data. The new data supports benthic-planktonic age offsets of no more than 300 years, indicating that bottom waters within the basin remained significantly younger during early deglaciation than some previous results have suggested and are thus consistent with sedimentary and faunal evidence for well-oxygenated conditions.

Magana, Alexandra L.; Southon, John R.; Kennett, James P.; Roark, E. Brendan; Sarnthein, Michael; Stott, Lowell D.

2010-12-01

270

Resolving the cause of large differences between deglacial benthic foraminifera radiocarbon measurements in Santa Barbara Basin  

NASA Astrophysics Data System (ADS)

To better understand the deglacial upwelling pattern in the East Pacific, we have made radiocarbon (14C) measurements on benthic foraminifera and macrofauna from a 3.5 meter long interval in ODP Core 893A from Santa Barbara Basin, California representing early deglaciation. This work serves to investigate the source of apparent disagreement between radiocarbon datasets from Leibnitz Laboratory, Kiel University (Kiel) and Carbon Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory (LLNL). These datasets are based on measurements of mixed benthic and mixed planktonic foraminifera. Inter-laboratory 14C results are similar for the planktonic foraminiferal analyses, however Kiel measurements on mixed benthic foraminifera are much older than mixed benthic measurements from equivalent depths measured at LLNL. Our new results show distinct 14C differences between taxa, with Pyrgo sp. giving ages consistently older than Kiel measurements on mixed benthic taxa; while ages for Nonionellina sp., Buliminella sp., Uvigerina sp. and benthic macrofauna were much younger- even younger than the LLNL mixed benthic data. The new data supports benthic-planktonic age offsets of no more than 300 years, indicating that bottom waters within the basin remained significantly younger during early deglaciation than some previous results have suggested and thus consistent with sedimentary and faunal evidence for well oxygenated conditions.

Magana, A. L.; Southon, J. R.; Kennett, J.; Roark, E.; Sarnthein, M.; Stott, L. D.

2010-12-01

271

Influences of Different Large Mammalian Fauna on Dung Beetle Diversity in Beech Forests  

PubMed Central

This paper focuses on biological relationships between mammalian species richness and the community structure of dung beetles in cool-temperate forests in the northernmost part of mainland Japan. The composition of beetle assemblages was evaluated at 3 sites in undisturbed beech forests with different mammalian fauna. In spring and summer 2009, beetles were collected at each site using pitfall traps baited with feces from Japanese macaques, Macaca fuscata Blyth (Primates: Cercopithecidae); Asiatic black bears, Ursus thibetanus Cuvier (Carnivora: Ursidae); Japanese serows, Capricornis crispus Temminck (Artiodactyla: Bovidae); and cattle. In the present study, 1,862 dung beetles representing 14 species were collected, and most dung beetles possessed the ecological characteristic of selecting specific mammalian feces. The present findings indicated that although species diversity in dung beetle assemblages was not necessarily positively correlated with mammalian species richness in cool-temperate forests, the absence of the macaque population directly resulted in the marked reduction of the beetle abundance, with the loss of the most frequent species, Aphodius eccoptus Bates (Coleoptera: Scarabaeidae) during spring. PMID:23909510

Enari, Hiroto; Koike, Shinsuke; Sakamaki, Haruka

2013-01-01

272

Large-Scale, Complex Shaped Coastline Responses to Different Forms of Local Shoreline Stabilization and Climate Change  

NASA Astrophysics Data System (ADS)

Nowhere is the importance of research addressing the dynamics of coupled human-landscape processes more pronounced than on the world’s coasts, where human shoreline stabilization alters the natural evolution of the coastline on large spatial and temporal scales. Slott et al. (2010) extended a recently developed large-scale coastline evolution model to include the effects of beach ‘nourishment’ (importing sand into the nearshore system at a long term rate sufficient to counteract shoreline erosion) on a complex-shaped coastline, finding a surprising human signal over large (100s km) distances (Figure 1); even localized shoreline stabilization efforts, when maintained over decadal time scales, can significantly affect the regional pattern of coastline morphological adjustment in response to changing storm behaviors (Slott, et al., 2010). In this work, we examine the effects of shoreline-stabilization method that involve hard structures, such as sea walls and groyne fields. These methods differ significantly from beach nourishment in terms of large-scale impacts; they hold the shoreline location fixed without adding a flux of sediment into the system. Like beach nourishment, these human manipulations have widespread, significant effects on shoreline change rates, even when the manipulations only occur locally. However, the effects on large-scale coastline morphodynamics also exhibit interesting differences when compared to the beach nourishment case. References Slott, Jordan, A. B. Murray, Andrew Ashton, 2010. Large-Scale Responses of Complex-Shaped Coastlines to Local Shoreline Stabilization and Climate Change, Journal of Geophysical Research—Earth Surface. Figure 1. Evolution of a cuspate-cape shoreline in response to ongoing beach nourishment over 200 years, for six different site selections. a. Initial model shoreline, developed in response to a wave climate approximating recent conditions off of the Carolina coast, USA. b. The influence that beach nourishment had on coastline change, with each curve representing a different model run in which nourishment occurred at one location only. The curves show the human signal (with the coastline change in a nourishment-free control run subtracted), normalized for the cuspate-cape shape of the shoreline. (After Slott et al., accepted.)

Ells, K.; Murray, A. B.; Slott, J. M.

2010-12-01

273

Is splash erosion potential species specific? Measuring of splash erosion potential under forest in different succession stages along a biodiversity gradient in the humid subtropics  

NASA Astrophysics Data System (ADS)

It is widely accepted that (forest) vegetation is a key control for the type and intensity of soil erosion. The current paradigm is that natural or quasi-natural vegetation protects the soil from erosion and that agricultural vegetation or land use generally enhances erosion. The latter was in focus of most research during the last decades and less interest was paid on natural systems, which are more difficult to study. Nevertheless, afforestation is widely used as a measure of soil protection against soil erosion. Rainfall can be highly erosive particularly in the humid subtropics. Regarding climate change, also precipitation regime may change in direction to even more severe storms and higher rainfall intensities; it is a research field of growing importance. Key mechanisms of a vegetation cover in reducing or enhancing erosion are modifications of drop-size distribution, retention of raindrop impact on the soil and changes in amount and spatial distribution of rainfall at the ground surface. Controlling determinants are rainfall intensity, drop size distribution, drop fall velocity, height of the canopy as well as density of the canopy, crown and leaf traits, LAI and coverage by a litter layer. Large drops are supposed to be significant sources of splash detachment in forests (Brandt 1989; Vis 1986). However, the mechanisms of reducing (or enhancing?) splash detachment under forest in relation to species richness and species composition are not well understood. Some studies indicate that raindrop impact is species specific (Calder 2001; Nanko et al. 2006) and some neglect the effects of species specific impacts (Foot & Morgan 2005). Our research uses different methods of rainfall characterization (splash cups, tipping-bucket rain gauge, laser distrometer) to reveal the described mechanisms from the canopy through different vegetation layers to the ground. First results of splash cup measurements (revised after Ellison 1947) show that sand loss under vegetation is 2.5 times higher than in open field despite the fact that only 60 percent of open field rainfall reaches the ground. The results also indicate that sand loss is a function of the age of the specific forest stand and the variability of sand loss under different species with respect to space and time. These and future results will help managing afforestation projects in giving implications which of the species (resp. species compositions) may reduce most effectively potential splash erosion. References: Brandt, C. J. (1989): The size distribution of throughfall drops under vegetation canopies. Catena 16, p. 507-524. Calder, I. R. (2001): Canopy processes: implications for transpiration, interception and splash induced erosion, ultimately for forest management and water resources. Plant Ecology 153, p. 203-214. Ellison, W. D. (1947): Soil Erosion Studies - Part II. Soil Detachment Hazard by Raindrop Splash. Agricultural Engineering 28, p. 197-201. Foot, K.; Morgan, R. P. C. (2005): The role of leaf inclination, leaf orientation and plant canopy architecture in soil particle detachment by raindrops. Earth Surface Processes and Landforms 30, p. 1509-1520. Nanko, K.; Hotta, N. & Suzuki, M. (2006): Evaluating the influence of canopy species and meteorological factors on throughfall drop size distribution. Journal of Hydrology 329, p. 422-431. Vis, M. (1986): Interception, drop size distributions and rainfall kinetic energy in four colombian forest ecosystems. Earth Surface Processes and Landforms 11, p. 591-603.

Geißler, C.; Kühn, P.; Scholten, T.

2009-04-01

274

Patterns in Benthic Biodiversity Link Lake Trophic Status to Structure and Potential Function of Three Large, Deep Lakes  

PubMed Central

Relative to their scarcity, large, deep lakes support a large proportion of the world’s freshwater species. This biodiversity is threatened by human development and is in need of conservation. Direct comparison of biodiversity is the basis of biological monitoring for conservation but is difficult to conduct between large, insular ecosystems. The objective of our study was to conduct such a comparison of benthic biodiversity between three of the world’s largest lakes: Lake Tahoe, USA; Lake Hövsgöl, Mongolia; and Crater Lake, USA. We examined biodiversity of common benthic organism, the non-biting midges (Chironomidae) and determined lake trophic status using chironomid-based lake typology, tested whether community structure was similar between the three lakes despite geographic distance; and tested whether chironomid diversity would show significant variation within and between lakes. Typology analysis indicated that Lake Hövsgöl was ultra-oligotrophic, Crater Lake was oligotrophic, and Lake Tahoe was borderline oligotrophic/mesotrophic. These results were similar to traditional pelagic measures of lake trophic status for Lake Hövsgöl and Crater Lake but differed for Lake Tahoe, which has been designated as ultra-oligotrophic by traditional pelagic measures such as transparency found in the literature. Analysis of similarity showed that Lake Tahoe and Lake Hövsgöl chironomid communities were more similar to each other than either was to Crater Lake communities. Diversity varied between the three lakes and spatially within each lake. This research shows that chironomid communities from these large lakes were sensitive to trophic conditions. Chironomid communities were similar between the deep environments of Lake Hövsgöl and Lake Tahoe, indicating that chironomid communities from these lakes may be useful in comparing trophic state changes in large lakes. Spatial variation in Lake Tahoe’s diversity is indicative of differential response of chironomid communities to nutrient enrichment which may be an indication of changes in trophic state within and across habitats. PMID:25594516

Hayford, Barbara L.; Caires, Andrea M.; Chandra, Sudeep; Girdner, Scott F.

2015-01-01

275

Study of fusion probabilities with halo nuclei using different proximity based potentials  

NASA Astrophysics Data System (ADS)

We study fusion of halo nuclei with heavy targets using proximity based potentials due to Aage Winther (AW) 95, Bass 80 and Proximity 2010. In order to consider the extended matter distribution of halo nuclei, the nuclei radii borrowed from cross section measurements are included in these potentials. Our study reveals that the barrier heights are effectively reduced and fusion cross sections are appreciably enhanced by including extended radii of these nuclei. We also find that the extended sizes of halos contribute towards enhancement of fusion probabilities in case of proton halo nuclei, but, contribute to transfer or break-up process rather than fusion yield in case of neutron halo nuclei.

Kumari, Raj

2013-11-01

276

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

277

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

278

A modified mirror projection visual evoked potential stimulator for presenting patterns in different orientations.  

PubMed

Modifications to a standard mirror projection visual evoked potential stimulator are described to enable projection of patterns in varying orientations. The galvanometer-mirror assembly is mounted on an arm which can be rotated through 90 degrees. This enables patterns in any orientation to be deflected perpendicular to their axes. PMID:2424725

Taylor, P K; Wynn-Williams, G M

1986-07-01

279

Event-Related Potential Studies of Attention to Shape Under Different Stimuli Tasks  

Microsoft Academic Search

Event-related potential (ERP) is a basic, non-invasive method of electrophysiological investigation. It can be used to assess aspects of human cognitive information processing. Recordings of ERPs from normal individuals have played an increasingly important role in our understanding of the mechanisms of attention. This paper focused on studies of specific cognitive subsystems such as visual pathway and attention with ERPs

Xu Guizhi; Zhang Ying; Hou Huijuan; Yan Weili

2006-01-01

280

Integrating Differences: Design Culture's Potential Impact on Contemporary Education  

ERIC Educational Resources Information Center

This qualitative study charted the implications and potentialities of embracing a design culture within contemporary education. Unlike the positivist scientific paradigm which dissects and analyzes, a design philosophy offers a unifying logic that facilitates change, acknowledges complexity, and shapes possibilities (Nelson & Stolterman,…

Uri, Therese

2012-01-01

281

Groundwater pollution potential and greenhouse gas emission from soils amended with different swine biochars  

Technology Transfer Automated Retrieval System (TEKTRAN)

Although there exist numerous research studies in the literature on greenhouse gas emission and groundwater pollution potentials of soils amended with plant-based biochar made from traditional dry pyrolysis (hereafter referred as pyrochar), a very few such studies exist for hydrochar made from hydro...

282

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

283

Regional difference in intestinal adaptation after total colectomy as judged by the changes of mucosal Na-K ATPase, cyclic AMP, and transmural potential difference.  

PubMed

Intestinal adaptation and its regional difference after total colectomy were investigated in dogs by measuring mucosal Na-K ATPase, cyclic AMP, and transmural electric potential difference (PD). Twenty-four weeks after the total proctocolectomy, Na-K ATPase activity and PD increased significantly in all intestinal sites, whereas cyclic AMP showed no significant changes. The regional difference in the remaining intestine was examined in the jejunum, ileum, and interposed jejunum (neorectum). Na-K ATPase activity showed no significant regional difference, but the largest increase was found to occur in the ileum. PD also increased markedly in the ileum and there was significant difference between the ileum and other intestinal sites. These facts suggest that the increased active ion transport mediated by mucosal Na-K ATPase and transmural PD in the ileum is closely related to the intestinal adaptation occurring after total colectomy and indicates a greater potential of the ileum for adaptive compensation than either jejunum or neorectum. PMID:2839319

Nakahara, S; Itoh, H; Mibu, R; Ikeda, S; Nakayama, F

1988-07-01

284

Potential Large Animal Models for Gene Therapy of Human Genetic Diseases of Immune and Blood Cell Systems  

PubMed Central

Genetic mutations involving the cellular components of the hematopoietic system—red blood cells, white blood cells, and platelets—manifest clinically as anemia, infection, and bleeding. Although gene targeting has recapitulated many of these diseases in mice, these murine homologues are limited as translational models by their small size and brief life span as well as the fact that mutations induced by gene targeting do not always faithfully reflect the clinical manifestations of such mutations in humans. Many of these limitations can be overcome by identifying large animals with genetic diseases of the hematopoietic system corresponding to their human disease counterparts. In this article, we describe human diseases of the cellular components of the hematopoietic system that have counterparts in large animal species, in most cases carrying mutations in the same gene (CD18 in leukocyte adhesion deficiency) or genes in interacting proteins (DNA cross-link repair 1C protein and protein kinase, DNA-activated, catalytic polypeptide in radiation-sensitive severe combined immunodeficiency). Furthermore, we describe the potential of these animal models to serve as disease-specific, preclinical models for testing the efficacy and safety of clinical interventions such as hematopoietic stem cell transplantation or gene therapy approaches before their use in humans with the corresponding disease. PMID:19293460

Bauer, Thomas R.; Adler, Rima L.; Hickstein, Dennis D.

2009-01-01

285

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. PMID:20215514

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

286

A class of singular logarithmic potentials in a box with different skin thicknesses and wall interactions  

NASA Astrophysics Data System (ADS)

We obtain an analytic solution for a three-parameter class of logarithmic potentials at zero energy. The potential terms are products of the inverse square and the inverse log to powers 2, 1 and 0. The configuration space is a one-dimensional box. Using point canonical transformation, we simplify the solution by mapping the problem into the oscillator problem. We also obtain an approximate analytic solution for non-zero energy when there is strong attraction to one side of the box. The wavefunction is written in terms of the confluent hypergeometric function. We also present a numerical scheme for calculating the energy spectrum for a general configuration and to any desired accuracy.

Alhaidari, A. D.

2010-12-01

287

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

288

Detecting potential safety issues in large clinical or observational trials by Bayesian screening when event counts arise from poisson distributions.  

PubMed

Patients in large clinical trials and in studies employing large observational databases report many different adverse events, most of which will not have been anticipated at the outset. Conventional hypothesis testing of between group differences for each adverse event can be problematic: Lack of significance does not mean lack of risk, the tests usually are not adjusted for multiplicity, and the data determine which hypotheses are tested. This article describes a Bayesian screening approach that does not test hypotheses, is self-adjusting for multiplicity, provides a direct assessment of the likelihood of no material drug-event association, and quantifies the strength of the observed association. The criteria for assessing drug-event associations can be determined by clinical or regulatory considerations. In contrast to conventional approaches, the diagnostic properties of this new approach can be evaluated analytically. Application of the method to findings from a vaccine trial yields results similar to those found by methods using a false discovery rate argument or a hierarchical Bayes approach. [Supplemental materials are available for this article. Go to the publisher's online edition of Journal of Biopharmaceutical Statistics for the following free supplemental resource: Appendix R: Code for calculations.]. PMID:23786257

Gould, A Lawrence

2013-01-01

289

Performance of different vector potential formulations in solving multiply connected 3-D eddy current problems  

Microsoft Academic Search

The authors describe their numerical experiences in applying FEM (finite-element method) solution techniques to a 3-D (three-dimensional) eddy-current problem with a coil-driven multiply connected conductor, the benchmark problem No.7 of the International TEAM Workshops. Several formulations have been tried using a magnetic vector and electric scalar potential or an electric vector and a magnetic scalar in the conductor and a

O. Biro; K. Preis; W. Renhart; K. R. Richter; G. Vrisk

1990-01-01

290

Photochemical ozone creation potentials (POCPs) for different emission sources of organic compounds under European conditions estimated with a Master Chemical Mechanism  

NASA Astrophysics Data System (ADS)

Through the combined application of a speciated VOC emission inventory and an explicit chemical mechanism, a picture has been put together of the different contributions to photochemical ozone formation from 248 VOC emission source categories. The study has shown that the different VOC emission source categories show vastly different propensities for forming photochemical ozone as indexed by their photochemical ozone creation potentials (POCPs). POCPs range from close to zero for numerous processes, including halocarbon solvent usage, through to over 70 for diesel combustion and some reactive solvent and other product usage applications. The consequences of the large range in POCPs are highlighted for cost-effective VOC emission control strategies across north west Europe.

Derwent, R. G.; Jenkin, M. E.; Passant, N. R.; Pilling, M. J.

291

The "Large" in Large Igneous Provinces: Using Digital Geological Maps to Determine the Area, Magma Flux, and Potential Environmental Impact of the Wrangellia Flood Basalts  

NASA Astrophysics Data System (ADS)

Large igneous provinces (LIPs), such as continental flood basalts and oceanic plateaus, are formed by relatively short duration, massive outpourings of basalt in intraplate settings. Their emplacement has been associated with global climatic and biotic change (e.g., end-Permian Siberian LIP). The magmatic products of a LIP typically cover an area >1 Mkm2, however erosion and exhumation may substantially reduce the original area and volume of a LIP, especially oceanic plateaus that have been tectonically dispersed during accretion (e.g., Caribbean, Wrangellia). The availability of digital geologic maps from government geologic surveys now allows for measuring the precise areal distribution of remnant LIP-products, which is essential information for estimating total volumes and ultimately potential environmental effects. The Wrangellia flood basalts represent one of the best-exposed accreted oceanic plateaus on Earth. This Triassic LIP is exposed in numerous fault-bound blocks in a belt extending discontinuously for 2300 km in the Pacific Northwest of North America. It contains exposures of submarine and subaerial volcanic rocks representing composite stratigraphic thicknesses of 3.5-6 km. From recently compiled digital geologic maps (British Columbia, Yukon, Alaska), the mapped exposures of the Wrangellia flood basalts are relatively small (25,256 km2 with 75% from Vancouver Island), which leads to minimum calculated erupted volumes of up to 1.4 x 105 km3 and an estimated magma flux of 0.03 km3/yr. The original areal distribution was substantially greater, perhaps by an order of magnitude or more, as the outcrop extent does not include regions covered by younger strata and surficial deposits nor does it account for the volcanic component of the terrane that may have been subducted. However, even this minimum volumetric output rate is comparable to recent estimates of long-term volumetric eruption rates for ocean islands such as Iceland (0.02-0.04 km3/yr) and Hawaii (0.02-0.08 km3/yr) [1]. The Wrangellia flood basalts were emplaced during a single phase of tholeiitic volcanism at ca. 230 Ma, possibly within as few as 2 Myr, onto preexisting submerged arc crust in equatorial latitudes in the eastern Panthalassic Ocean. This age corresponds to the Carnian-Norian boundary of the Upper Triassic [2], a time of global-scale climatic and biotic crisis, which was followed by strong radiation of the dinosaurs. A combination of precise U-Pb geochronology of the Wrangellia basalts, area/magma flux estimates (including integration of geophysical seismic reflection profiles to account for plutonic components) and quantification of the associated volatile production will be required to fully evaluate this potential link between volcanic activity and global environmental impacts. [1] White, S.M. et al. (2006) Geochemistry Geophysics Geosystems, 7, Q03010, doi: 10.1029/2005GC001002. [2] Furin, S. et al. (2006) Geology 34, 1009-1012, doi: 10.1130/G22967A.1.

Scoates, J. S.; Greene, A. R.; Weis, D. A.

2010-12-01

292

Differences in rural and urban driver-injury severities in accidents involving large-trucks: an exploratory analysis.  

PubMed

This study explores the differences between urban and rural driver injuries (both passenger-vehicle and large-truck driver injuries) in accidents that involve large trucks (in excess of 10,000 pounds). Using 4 years of California accident data, and considering four driver-injury severity categories (no injury, complaint of pain, visible injury, and severe/fatal injury), a multinomial logit analysis of the data was conducted. Significant differences with respect to various risk factors including driver, vehicle, environmental, road geometry and traffic characteristics were found to exist between urban and rural models. For example, in rural accidents involving tractor-trailer combinations, the probability of drivers' injuries being severe/fatal increased about 26% relative to accidents involving single-unit trucks. In urban areas, this same probability increased nearly 700%. In accidents where alcohol or drug use was identified as being the primary cause of the accident, the probability of severe/fatal injury increased roughly 250% percent in rural areas and nearly 800% in urban areas. While many of the same variables were found to be significant in both rural and urban models (although often with quite different impact), there were 13 variables that significantly influenced driver-injury severity in rural but not urban areas, and 17 variables that significantly influenced driver-injury severity in urban but not rural areas. We speculate that the significant differences between rural and urban injury severities may be at least partially attributable to the different perceptual, cognitive and response demands placed on drivers in rural versus urban areas. PMID:15935320

Khorashadi, Ahmad; Niemeier, Debbie; Shankar, Venky; Mannering, Fred

2005-09-01

293

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

294

Hemispheric Differences in the Time-Course of Semantic Priming Processes: Evidence from Event-Related Potentials (ERPs)  

ERIC Educational Resources Information Center

To investigate hemispheric differences in the timing of word priming, the modulation of event-related potentials by semantic word relationships was examined in each cerebral hemisphere. Primes and targets, either categorically (silk-wool) or associatively (needle-sewing) related, were presented to the left or right visual field in a go/no-go…

Bouaffre, Sarah; Faita-Ainseba, Frederique

2007-01-01

295

Different NMDA receptor subtypes mediate induction of long-term potentiation and two forms of short-term potentiation at CA1 synapses in rat hippocampus in vitro  

PubMed Central

Potentiation at synapses between CA3 and the CA1 pyramidal neurons comprises both transient and sustained phases, commonly referred to as short-term potentiation (STP or transient LTP) and long-term potentiation (LTP), respectively. Here, we utilized four subtype-selective N-methyl-d-aspartate receptor (NMDAR) antagonists to investigate whether the induction of STP and LTP is dependent on the activation of different NMDAR subtypes. We find that the induction of LTP involves the activation of NMDARs containing both the GluN2A and the GluN2B subunits. Surprisingly, however, we find that STP can be separated into two components, the major form of which involves activation of NMDARs containing both GluN2B and GluN2D subunits. These data demonstrate that synaptic potentiation at CA1 synapses is more complex than is commonly thought, an observation that has major implications for understanding the role of NMDARs in cognition. PMID:23230236

Volianskis, Arturas; Bannister, Neil; Collett, Valerie J; Irvine, Mark W; Monaghan, Daniel T; Fitzjohn, Stephen M; Jensen, Morten S; Jane, David E; Collingridge, Graham L

2013-01-01

296

The Structure of Pre-transitional Protoplanetary Disks. II. Azimuthal Asymmetries, Different Radial Distributions of Large and Small Dust Grains in PDS 70  

NASA Astrophysics Data System (ADS)

The formation scenario of a gapped disk, i.e., transitional disk, and its asymmetry is still under debate. Proposed scenarios such as disk-planet interaction, photoevaporation, grain growth, anticyclonic vortex, eccentricity, and their combinations would result in different radial distributions of the gas and the small (sub-?m size) and large (millimeter size) dust grains as well as asymmetric structures in a disk. Optical/near-infrared (NIR) imaging observations and (sub-)millimeter interferometry can trace small and large dust grains, respectively; therefore multi-wavelength observations could help elucidate the origin of complicated structures of a disk. Here we report Submillimeter Array observations of the dust continuum at 1.3 mm and 12CO J = 2 ? 1 line emission of the pre-transitional protoplanetary disk around the solar-mass star PDS 70. PDS 70, a weak-lined T Tauri star, exhibits a gap in the scattered light from its disk with a radius of ~65 AU at NIR wavelengths. However, we found a larger gap in the disk with a radius of ~80 AU at 1.3 mm. Emission from all three disk components (the gas and the small and large dust grains) in images exhibits a deficit in brightness in the central region of the disk, in particular, the dust disk in small and large dust grains has asymmetric brightness. The contrast ratio of the flux density in the dust continuum between the peak position to the opposite side of the disk reaches 1.4. We suggest the asymmetries and different gap radii of the disk around PDS 70 are potentially formed by several (unseen) accreting planets inducing dust filtration.

Hashimoto, J.; Tsukagoshi, T.; Brown, J. M.; Dong, R.; Muto, T.; Zhu, Z.; Wisniewski, J.; Ohashi, N.; kudo, T.; Kusakabe, N.; Abe, L.; Akiyama, E.; Brandner, W.; Brandt, T.; Carson, J.; Currie, T.; Egner, S.; Feldt, M.; Grady, C. A.; Guyon, O.; Hayano, Y.; Hayashi, M.; Hayashi, S.; Henning, T.; Hodapp, K.; Ishii, M.; Iye, M.; Janson, M.; Kandori, R.; Knapp, G.; Kuzuhara, M.; Kwon, J.; Matsuo, T.; McElwain, M. W.; Mayama, S.; Mede, K.; Miyama, S.; Morino, J.-I.; Moro-Martin, A.; Nishimura, T.; Pyo, T.-S.; Serabyn, G.; Suenaga, T.; Suto, H.; Suzuki, R.; Takahashi, Y.; Takami, M.; Takato, N.; Terada, H.; Thalmann, C.; Tomono, D.; Turner, E. L.; Watanabe, M.; Yamada, T.; Takami, H.; Usuda, T.; Tamura, M.

2015-01-01

297

On the relationship between the tree and its environment, based on electrical potential difference monitoring on trunk of trees  

NASA Astrophysics Data System (ADS)

Electrical potential differences (EPD) in the trunk of a Turkey oak tree (measured by using non-polarising electrodes deepened in the sap wood) have been continuously recorded in the Geophysical Observatory "Istv n Széchenyi" of the Hungarian Academy of Sciences since 1997. Besides of various geophysical observations, meteorological and direct sap-flow measurements have also been carried out in the observatory. As it was found (Kopp n A., Szarka L., Wesztergom V., 2000: Annual fluctuation in amplitudes of daily variations of electrical signals measured in the trunk of a standing tree. C.R. Acad. Sci. Paris, Life Sciences 323, 559-563), the measured electric potential difference data have a characteristic sinusoidal daily fluctuation, and the intensity of the diurnal variations has a double-peak annual characteristics, which coincides with the life activity maximums of the tree. We have found a remarkable inter-correlation between trunk EPD, water potential of air (derived from meteorological data), and direct sap flow velocity data from a neighboring tree. All these results clearly demonstrate that the sap streaming due to the transpiration and root pressure generates the largest part of measured potential differences. The ratio of the flow velocity of a diluted solution forced through stems and the potential differences was found to be constant (Gindl, W., L”ppert, H.-G., Wimmer, R., 1999: Relationship between streaming potential and sap velocity in Salix alba L. Phyton, 39, 217-224.). On the contrary in our in-vivo experiments the relationship between the measured sap flow velocity and EPD is non-linear, which means that the conductivity (i.e. ion concentration) of the xylem sap itself also has a daily fluctuation.

Koppan, A.; Fenyvesi, A.; Szarka, L.; Wesztergom, V.

2002-05-01

298

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. PMID:22843516

Mehta-Kolte, Misha G.

2012-01-01

299

Identification of Different Types of Spinal Afferent Nerve Endings That Encode Noxious and Innocuous Stimuli in the Large Intestine Using a Novel Anterograde Tracing Technique  

PubMed Central

In mammals, sensory stimuli in visceral organs, including those that underlie pain perception, are detected by spinal afferent neurons, whose cell bodies lie in dorsal root ganglia (DRG). One of the major challenges in visceral organs has been how to identify the different types of nerve endings of spinal afferents that transduce sensory stimuli into action potentials. The reason why spinal afferent nerve endings have been so challenging to identify is because no techniques have been available, until now, that can selectively label only spinal afferents, in high resolution. We have utilized an anterograde tracing technique, recently developed in our laboratory, which facilitates selective labeling of only spinal afferent axons and their nerve endings in visceral organs. Mice were anesthetized, lumbosacral DRGs surgically exposed, then injected with dextran-amine. Seven days post-surgery, the large intestine was removed. The characteristics of thirteen types of spinal afferent nerve endings were identified in detail. The greatest proportion of nerve endings was in submucosa (32%), circular muscle (25%) and myenteric ganglia (22%). Two morphologically distinct classes innervated myenteric ganglia. These were most commonly a novel class of intraganglionic varicose endings (IGVEs) and occasionally rectal intraganglionic laminar endings (rIGLEs). Three distinct classes of varicose nerve endings were found to innervate the submucosa and circular muscle, while one class innervated internodal strands, blood vessels, crypts of lieberkuhn, the mucosa and the longitudinal muscle. Distinct populations of sensory endings were CGRP-positive. We present the first complete characterization of the different types of spinal afferent nerve endings in a mammalian visceral organ. The findings reveal an unexpectedly complex array of different types of primary afferent endings that innervate specific layers of the large intestine. Some of the novel classes of nerve endings identified must underlie the transduction of noxious and/or innocuous stimuli from the large intestine. PMID:25383884

Spencer, Nick J.; Kyloh, Melinda; Duffield, Michael

2014-01-01

300

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. PMID:18680587

Kretzschmar, Mirjam; Zhang, Weidong; Mikolajczyk, Rafael T; Wang, Lan; Sun, Xinhua; Kraemer, Alexander; Lv, Fan

2008-01-01

301

Recent progress on phospholipases: different sources, assay methods, industrial potential and pathogenicity.  

PubMed

Significant studies on phospholipases optimization, characterization, physiological role and industrial potential have been conducted worldwide. Some of them have been directed for biotechnological advances such as gene discovery and functional enhancement by protein engineering. Others reported phospholipases as virulence factor and major cause of pathophysiological effects. A general overview on phospholipase is needed for the identification of new reliable and efficient phospholipase, which would be potentially used in number of industrial and medical applications. Phospholipases catalyse the hydrolysis of one or more ester and phosphodiester bonds of glycerophospholipids. They vary in site of action on phospholipid which can be used industrially for modification/production of new phospholipids. Catalytically active phospholipase mainly use phosphatidylcholine as major substrate, but they can also show specificity with other phospholipids. Several accurate phospholipase assay methods are known, but a rapid and reliable method for high-throughput screening is still a challenge for efficient supply of superior phospholipases and their practical applications. Major application of phospholipase is in industries like oil refinery, health food manufacturing, dairy, cosmetics etc. All types of phospholipases can be involved as virulence factor. They can also be used as diagnostic markers for microbial infection. The importance of phospholipase in virulence is proven and inhibitors of the enzyme can be used as candidate for preventing the associated disease. PMID:21302142

Ramrakhiani, Lata; Chand, Subhash

2011-08-01

302

The Difference Between Potential and Achieved Academic Performance of Freshmen Residents at North Carolina State University.  

ERIC Educational Resources Information Center

Differences in academic performance of residents in the various sections and dormitories during the fall semester 1974 at North Carolina State University were studied. Other study objectives were as follows: to develop a methodology to measure academic performance of freshmen residents adjusted for ability, sex, and differential grading…

Viehe, John Henry

303

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

304

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. PMID:23874446

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

2013-01-01

305

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

306

Stellar metallicities beyond the Local Group: the potential of J-band spectroscopy with extremely large telescopes  

NASA Astrophysics Data System (ADS)

We present simulated J-band spectroscopy of red giants and supergiants with a 42 m European Extremely Large Telescope (E-ELT), using tools developed toward the EAGLE Phase A instrument study. The simulated spectra are used to demonstrate the validity of the 1.15-1.22 ?m region to recover accurate stellar metallicities from Solar and metal-poor (one tenth Solar) spectral templates. From tests at spectral resolving powers of four and ten thousand, we require continuum signal-to-noise ratios in excess of 50 (per two-pixel resolution element) to recover the input metallicity to within 0.1 dex. We highlight the potential of direct estimates of stellar metallicites (over the range - 1 < [Fe/H] < 0) of red giants with the E-ELT, reaching out to distances of ~ 5 Mpc for stars near the tip of the red giant branch. The same simulations are also used to illustrate the potential for quantitative spectroscopy of red supergiants beyond the Local Volume to tens of Mpc. Calcium triplet observations in the I-band are also simulated to provide a comparison with contemporary techniques. Assuming the EAGLE instrument parameters and simulated performances from adaptive optics, the J-band method is more sensitive in terms of recovering metallicity estimates for a given target. This appears very promising for ELT studies of red giants and supergiants, offering a direct metallicity tracer at a wavelength which is less affected by extinction than shortward diagnostics and, via adaptive optics, with better image quality.

Evans, C. J.; Davies, B.; Kudritzki, R.-P.; Puech, M.; Yang, Y.; Cuby, J.-G.; Figer, D. F.; Lehnert, M. D.; Morris, S. L.; Rousset, G.

2011-03-01

307

Strains of the soil fungus Mortierella show different degradation potentials for the phenylurea herbicide diuron.  

PubMed

Microbial pesticide degradation studies have until now mainly focused on bacteria, although fungi have also been shown to degrade pesticides. In this study we clarify the background for the ability of the common soil fungus Mortierella to degrade the phenylurea herbicide diuron. Diuron degradation potentials of five Mortierella strains were compared, and the role of carbon and nitrogen for the degradation process was investigated. Results showed that the ability to degrade diuron varied greatly among the Mortierella strains tested, and the strains able to degrade diuron were closely related. Degradation of diuron was fastest in carbon and nitrogen rich media while suboptimal nutrient levels restricted degradation, making it unlikely that Mortierella utilize diuron as carbon or nitrogen sources. Degradation kinetics showed that diuron degradation was followed by formation of the metabolites 1-(3,4-dichlorophenyl)-3-methylurea, 1-(3,4-dichlorophenyl)urea and an hitherto unknown metabolite suggested to be 1-(3,4-dichlorophenyl)-3-methylideneurea. PMID:23361127

Ellegaard-Jensen, Lea; Aamand, Jens; Kragelund, Birthe B; Johnsen, Anders H; Rosendahl, Søren

2013-11-01

308

miR-214: a potential biomarker and therapeutic for different cancers.  

PubMed

ABSTRACT? miRNAs (miRs), or small approximately 22-nucleotide-long single-stranded noncoding RNA molecules, interact with 3' untranslated regions of target mRNAs, leading to inhibition of protein production. miR-214 is often dysregulated in various cancers, which governs both tumorigenic and tumor suppressive functions. This review focuses on the current knowledge of miR-214 switching in diverse forms of cancer either by its upregulation or downregulation and sheds light on the mechanism of its tumorigenic and suppressive roles. This article describes known targets and signaling pathways that impact tumorigenesis and tumor suppression and summarizes all information available on circulating levels of miR-214 to address whether miR-214 may function as a potential biomarker and therapy for cancer patients in the future. PMID:25591843

Sharma, Tanu; Hamilton, Ryan; Mandal, Chandi C

2015-01-01

309

The thermodynamic activity of proline in ternary solutions of different water potentials.  

PubMed

The particular colligative properties of proline caused us to investigate the thermodynamic activity of this amino acid in detail. The dependence of the activity coefficients ? of proline (? = thermodynamic activity/molality) on the pH of the solutions, the composition of the solution and the water potential has been measured. The results show that the activity coefficient of proline varies according to the solute milieu. The most pronounced alterations of the activity coefficient could be observed in polyethylene glycol solutions in contrast to KCl- and saccharose solutions where the effect was less distinct. The results described provide a basis for discussing water stress induced metabolic alterations in terms of thermodynamic entities. Changed rates of proline metabolizing sequences and changed ratios of the vacuole/extravacuole distribution of this amino acid in stressed and un-stressed plants may partially be explained by thermodynamic causes. PMID:23196091

Pahlich, E; Stadermann, T

1984-06-01

310

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

311

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

312

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

313

Cytotoxic and genotoxic potential of drinking water: a comparison between two different concentration methods.  

PubMed

The level of exposure to hazardous compounds through drinking water is low but it is maintained throughout life, therefore representing a risk factor for human health. The use of techniques averaging the consumer's exposure over time could be more useful than relying on intermittent grab samples that may misrepresent average tap water concentrations due to short-term temporal variability. In this study, we compared the induction of in vitro cytotoxic and genotoxic effects (DNA damage by the comet assay) in relation to different sampling methods, i.e. exposure over time (semipermeable membrane devices, SPMDs, exposed for 30 days) or intermittent grab samples (5 weekly water sampling, C18 concentration). Waters with different chemical characteristics were sampled to test the sensitivity of the two methods. We did not found any positive correlation between the biological findings and water chemical parameters. SPMD extracts induced a significantly greater DNA damage than C18. The different behaviour was specially found for the water samples with a low level of organic compounds and when C18 extracts were highly cytotoxic. Our findings suggest that SPMD could be of a great interest in assessing genotoxic contaminants in both raw and drinking water, with great suitability for continuous monitoring. Furthermore, the results of this study have confirmed the great importance of the biological assays in evaluating the effects of a complex mixture such as water in addition to the conventional chemical examination of water quality. PMID:18199468

Buschini, Annamaria; Giordani, Federica; Pellacani, Claudia; Rossi, Carlo; Poli, Paola

2008-04-01

314

A comparison of two different approaches for mapping potential ozone damage to vegetation. A model study.  

PubMed

Two very different types of approaches are currently in use today for indicating risk of ozone damage to vegetation in Europe. One approach is the so-called AOTX (accumulated exposure over threshold of Xppb) index, which is based upon ozone concentrations only. The second type of approach entails an estimate of the amount of ozone entering via the stomates of vegetation, the AFstY approach (accumulated stomatal flux over threshold of Y nmol m(-2) s(-1)). The EMEP chemical transport model is used to map these different indicators of ozone damage across Europe, for two illustrative vegetation types, wheat and beech forests. The results show that exceedences of critical levels for either type of indicator are widespread, but that the indicators give very different spatial patterns across Europe. Model simulations for year 2020 scenarios suggest reductions in risks of vegetation damage whichever indicator is used, but suggest that AOT40 is much more sensitive to emission control than AFstY values. PMID:16762467

Simpson, D; Ashmore, M R; Emberson, L; Tuovinen, J-P

2007-04-01

315

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

316

Structure of Large Nitrate-Water Clusters at Ambient Temperatures: Simulations with Effective Fragment Potentials and Force Fields with Implications for Atmospheric Chemistry  

NASA Astrophysics Data System (ADS)

Structural properties of large NO3-·(H2O)n (n = 15-500) clusters are studied by Monte Carlo simulations using effective fragment potentials (EFPs) and by classical molecular dynamics simulations using a polarizable empirical force field. The simulation results are analyzed with a focus on the description of hydrogen bonding and solvation in the clusters. In addition, a comparison between the electronic structure based EFP and the classical force field description of the 32 water cluster system is presented. The EFP simulations, which focused on the cases of n = 15 and 32, show an internal, fully solvated structure and a "surface adsorbed" structure for the 32 water cluster at 300 K, with the latter configuration being more probable. The internal solvated structure and the "surface adsorbed" structure differ considerably in their hydrogen bonding coordination numbers. The force field based simulations agree qualitatively with these results, and the local geometry of NO3- and solvation at the surface-adsorbed site in the force field simulations are similar to those predicted using EFPs. Differences and similarities between the description of hydrogen bonding of the anion in the two approaches are discussed. Extensive classical force field based simulations at 250 K predict that long time scale stability of "internal" NO3-, which is characteristic of extended bulk aqueous interfaces, emerges only for n > 300. Ab initio Møller-Plesset perturbation theory is used to test the geometries of selected surface and interior anions for n = 32, and the results are compared to the EFP and MD simulations. Qualitatively, all approaches agree that surface structures are preferred over the interior structures for clusters of this size. The relatively large aqueous clusters of NO3- studied here are of comparable size to clusters that lead to new particle formation in air. Nitrate ions on the surface of such clusters may have significantly different photochemistry than the internal species. The possible implications of surface-adsorbed nitrate ions for atmospheric chemistry are discussed.

Miller, Yifat; Thomas, Jennie L.; Kemp, Daniel D.; Finlayson-Pitts, Barbara J.; Gordon, Mark S.; Tobias, Douglas J.; Gerber, R. Benny

2009-10-01

317

Investigation of Phenolic Profiles, Cytotoxic Potential and Phytochemical Screening of Different Extracts of Drynaria quercifolia J. Smith (Leaves)  

PubMed Central

Purpose: The present study is aimed to evaluate phenolic profiles, cytotoxic activity and phytochemical screening of different extracts of Drynaria quercifolia leaves. Methods: The dried and powder leaves were extracted with methanol at room temperature and the concentrated methanolic extract was fractionated by the modified Kupchan partitioning method to provide pet-ether, carbon tetrachloride, chloroform and aqueous soluble fractions. Phenolic profiles were determined by using Folin-Ciocalteau reagent, which results were expressed in gallic acid equivalent (mg of GAE/g of sample). Phytochemical properties of different extractives of plant materials were tested by the method of Trease and Evans. Brine shrimp lethality bioassay was used to investigate the cytotoxic potential of D. quercifolia. Results: The phytochemical screening revealed the potent source of different phytochemical constituents on different extractives including alkaloid, glycosides, tannin, saponins, proteins and amino acids, flavonoids, triterpenes, phenols, phytosterols and carbohydrate. In the determination of phenolic profiles, different extractives showed a significant content of phenolic compounds ranging from 103.43 -132.23 mg of GAE/g of extractive. Compared to vincristine sulfate different extractives of plant materials demonstrated moderate cytotoxic potential (having LC50 of 12.45 ?g/ml, 13.02 ?g/ml 15.83 ?g/ml, 14.95 ?g/ml and 7.612 ?g/ml, respectively). Conclusion: It is concluded from this study that D. quercifolia is an excellent source of phenolic content and phytoconstitutes as well as possesses moderate cytotoxic activity. PMID:24312880

Runa, Jannatul Ferdous; Hossain, Marjan; Hasanuzzaman, Md.; Ali, Md. Ramjan

2013-01-01

318

Potential Impacts of Mineral Dust Aerosol From Different Regions on Warm and Cold Cloud Formation  

NASA Astrophysics Data System (ADS)

Dusts from various regions of the world can have different solubilities, chemical and surface properties that affect warm and cold cloud formation in a variety of ways that are not fully understood. We investigated the interaction of water vapor with several types of dust aerosol, collected from the Southwest U.S. and the Saharan region. Hygroscopic growth of the particles was determined using a humidified tandem differential mobility analyzer and cloud drop nucleating activity was measured using a continuous flow cloud condensation nucleus (CCN) counter. A continuous flow diffusion chamber was operated in the temperature range of - 60different effects on the particles at different temperatures. The wet-generated particles were more active CCN than the dry-generated due to the artificial soluble coating on the particle surface. However, at sub-freezing temperatures, the soluble coating appeared to inhibit the formation of ice, requiring higher RH for ice nucleation than in the dry-generated case. Some of the wet- generated particle types exhibited a temperature dependence for freezing similar to that for freezing of solution drops, yet ice initiation occurred for the coated dust particles at lower RH than in aqueous solution drops, indicating the role of the mineral dust surface in catalyzing freezing.

Koehler, K.; Kreidenweis, S.; Demott, P.; Prenni, A.; Petters, M.

2006-12-01

319

Antioxidant potential of different melatonin-loaded nanomedicines in an experimental model of sepsis.  

PubMed

Oxidative stress has been shown to play a major role in the complex pathophysiological processes leading to organ failure during sepsis. The aim of the present research was to evaluate the effect of different melatonin nanoparticle (NP) carriers in an experimental animal model of sepsis. Poly-D,L-lactide-co-glycolide (PLGA [NP-A]) and polyethylene glycol-co-(poly-D,L-lactide-co-glycolide) (PLGA-PEG [NP-B]) were used to obtain melatonin-loaded nanocarriers (10 mg/kg). Oxidative stress was measured in tissue homogenates by measuring heme oxygenase-1 (HO-1) expression, total thiol groups and lipid hydroperoxides (LOOH). In vitro NPs showed a long lag time followed by a controlled release of melatonin. All the different melatonin formulations restored total thiol group levels to those of controls in all the examined organs, with no significant changes among them. Both melatonin NP formulations significantly decreased LOOH levels when compared with sepsis vehicle animals. The stealth formulation NP-B was able to produce a more significant reduction in LOOH levels in the heart, lung and liver when compared with NP-A. No significant changes were observed between the two NP formulations in the kidney. Interestingly, HO-1 expression was differently affected following treatment with various melatonin formulations. The NP-B formulation was more effective in inducing HO-1 protein compared with free melatonin and NP-A, with the exception of the kidney. Taken together, our results show that melatonin possesses a significant antioxidant activity during sepsis and that it is possible to improve this ability by delivering the compound with specific drug delivery systems. PMID:22728708

Li Volti, Giovanni; Musumeci, Teresa; Pignatello, Rosario; Murabito, Paolo; Barbagallo, Ignazio; Carbone, Claudia; Gullo, Antonino; Puglisi, Giovanni

2012-06-01

320

Regional differences in the potential exposure of US minority populations to hazardous facilities  

SciTech Connect

In the literature that examines the distribution of environmental disamenities of various types, there is considerable documentation that minority groups and lower income groups are more likely to be exposed. Such differential exposure has been attributed to environmental racism'' by some authors, but there has been no systematic investigation of the factors and dynamics underlying this exposure pattern. This study examines regional differences in the proximity of African-American, Hispanics, Asians, and non-Hispanic Whites to a broad range facility types and explores the degree to which this may be related to urban and income factors.

Nieves, L.A. (Argonne National Lab., IL (United States)); Nieves, A.L. (Wheaton Coll., Wheaton, IL (United States) Argonne National Lab., IL (United States))

1992-01-01

321

Regional differences in the potential exposure of US minority populations to hazardous facilities  

SciTech Connect

In the literature that examines the distribution of environmental disamenities of various types, there is considerable documentation that minority groups and lower income groups are more likely to be exposed. Such differential exposure has been attributed to ``environmental racism`` by some authors, but there has been no systematic investigation of the factors and dynamics underlying this exposure pattern. This study examines regional differences in the proximity of African-American, Hispanics, Asians, and non-Hispanic Whites to a broad range facility types and explores the degree to which this may be related to urban and income factors.

Nieves, L.A. [Argonne National Lab., IL (United States); Nieves, A.L. [Wheaton Coll., Wheaton, IL (United States)]|[Argonne National Lab., IL (United States)

1992-12-01

322

Low Plasma Leptin in Cognitively Impaired ADNI Subjects: Gender Differences and Diagnostic and Therapeutic Potential  

PubMed Central

Analysis of data derived from the Alzheimer's Disease Neuroimaging Initiative (ADNI) program showed plasma leptin levels in individuals with Mild Cognitive Impairment (MCI) or Alzheimer's disease (AD) to be lower than those of subjects with normal cognition (NC). Approximately 70% of both men and women with MCI have plasma leptin levels lower than the median values of NC. Additionally, half of these subjects carry at least one apolipoprotein-E4 (APOE-?4) allele. A subgroup of participants also had cerebrospinal fluid (CSF) leptin measured. Plasma leptin typically reflected the levels of leptin in CSF in all groups (Control/MCI/AD) in both genders. The data suggest that plasma leptin deficiency provides an indication of potential CNS leptin deficiency, further supporting the exploration of plasma leptin as a diagnostic marker for MCI or AD. The important question is whether leptin deficiency plays a role in the causation of AD and/or its progression. If this is the case, individuals with early AD or MCI with low plasma leptin may benefit from leptin replacement therapy. Thus, these data indicate that trials of leptin in low leptin MCI/early-stage AD patients should be conducted to test the hypothesis. PMID:24359504

Johnston, Jane M.; Hu, William T.; Fardo, David W.; Greco, Steven J.; Perry, George; Montine, Thomas J.; Trojanowski, John Q.; Shaw, Leslie M.; Ashford, J. Wesson; Tezapsidis, Nikolaos

2014-01-01

323

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 of feed ingredients to be used in the formulation of diets. PMID:25049760

Kim, Seon-Ho; Mamuad, Lovelia L.; Jeong, Chang-Dae; Choi, Yeon-Jae; Lee, Sung Sill; Ko, Jong-Youl; Lee, Sang-Suk

2013-01-01

324

Sensory potentials evoked by tactile stimulation of different indentation velocities at the finger and palm.  

PubMed

Previous studies suggest that the rate of indentation of a tactile probe determines which skin mechanoreceptors are activated. To further investigate this possibility, indentations of 300 microm at velocities of 100 (T100) and 400 microm/ms (T400) were applied to the tip (FT) and the proximal phalanx of digit III (PP) and the thenar eminence (Pm) of ten healthy volunteers, and compared with responses after electrical stimulation at the FT. Compound sensory action potentials (CSAPs) were recorded from the median nerve through needle electrodes at the wrist and elbow. The maximal sensory conduction velocities (SNCVs) between wrist and elbow were similar with electrical and T400 stimulation, but on average were 15% lower with T100 stimulation (P < 0.001). With both indentation velocities, SNCVs were similar regardless of stimulation sites. Amplitudes of tactile CSAPs with FT stimulation were 1--2 microV at T400 and 0.3--0.4 microV at T100. The CSAP areas evoked by T100 stimulation showed a reduction from fingertip to proximal finger to palm (P < 0.05-0.005), whereas those obtained with T400 stimulation showed a reduction only at the palm (P < 0.05). The results support previous studies indicating that fast indentation at 400 microm/ms activated deeply placed Pacinian corpuscles as well as superficially situated Meissner corpuscles, whereas slower indentation at 100 microm/ms activated primarily Meissner corpuscles. PMID:11494275

Baba, M; Simonetti, S; Krarup, C

2001-09-01

325

Identifying the Potential for Robotics to Assist Older Adults in Different Living Environments.  

PubMed

As the older adult population grows and becomes more diverse, so will their needs and preferences for living environments. Many adults over 65 years of age require some assistance [1, 2]; yet it is important for their feelings of well-being that the assistance not restrict their autonomy [3]. Not only is autonomy correlated with quality of life [4], autonomy enhancement may improve functionality [2, 5]. The goal of this paper is to provide guidance for the development of technology to enhance autonomy and quality of life for older adults. We explore the potential for robotics to meet these needs. We evaluated older adults' diverse living situations and the predictors of residential moves to higher levels of care in the United States. We also examined older adults' needs for assistance with activities of daily living (ADLs), instrumental activities of daily living (IADLs), and medical conditions when living independently or in a long-term care residence. By providing support for older adults, mobile manipulator robots may reduce need-driven, undesired moves from residences with lower levels of care (i.e., private homes, assisted living) to those with higher levels of care (i.e., skilled nursing). PMID:24729800

Mitzner, Tracy L; Chen, Tiffany L; Kemp, Charles C; Rogers, Wendy A

2014-04-01

326

Assessment of Antioxidant Potential, Total Phenolics and Flavonoids of Different Solvent Fractions of Monotheca Buxifolia Fruit  

PubMed Central

Objectives This study was conducted to investigate the antioxidant potential of methanol extract and its derived fractions (hexane, ethyl acetate, butanol, and aqueous) of fruits of Monotheca buxifolia (Falc.) Dc., a locally used fruit in Pakistan. Methods Dried powder of the fruit of M. buxifolia was extracted with methanol and the resultant was fractionated with solvents having escalating polarity; n-hexane, chloroform, ethyl acetate, n-butanol and the residual soluble aqueous fraction. Total phenolic and total flavonoid contents were estimated for the methanol and various fractions. These fractions were also subjected to various in vitro assays to estimate the scavenging activity for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), superoxide, hydroxyl, hydrogen peroxide and reductive ability for ferric ions and phosphomolybdate assay. Results The n-butanol, aqueous and methanol fractions possessed high amount of phenolics and flavonoids compared with other fractions, and subsequently showed a pronounced scavenging activity on DPPH, ABTS, superoxide, hydroxyl and hydrogen peroxide radicals and had a potent reductive ability on ferric ion and phosphomolybdate assay. There was a found significant correlation between total phenolic and flavonoid contents and EC50 of DPPH, superoxide, hydrogen peroxide radical and phosphomolybdate assays, whereas a nonsignificant correlation was found with the hydroxyl radical and ABTS radical assay. Conclusion M. buxifolia fruit can be used as natural antioxidant source to prevent damage associated with free radicals. PMID:24298440

Jan, Shumaila; Khan, Muhammad Rashid; Rashid, Umbreen; Bokhari, Jasia

2013-01-01

327

Chromium accumulation potential of Zea mays grown under four different fertilizers.  

PubMed

Chromium (Cr) contamination in soil is a growing concern in sustainable agriculture production and food safety. We performed pot experiment with chromium (30 mg/soil) to assess the accumulation potential of Zea mays and study the influence of four fertilizers, viz. Farm Yard Manure (FYM), NPK, Panchakavya (PK) and Vermicompost (VC) with respect to Cr accumulation. The oxidative stress and pigment (chlorophyll) levels were also examined. The results showed increased accumulation of chromium in both shoots and roots of Zea mays under FYM and NPK supply, and reduced with PK and VC. While the protein and pigment contents decreased in Cr treated plants, the fertilizers substantiated the loss to overcome the stress. Similarly, accumulation of Cr increased the levels of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) indicating the enhanced damage control activity. However, these levels were relatively low in plants supplemented with fertilizers. Our results confirm that the maize can play an effective role in bioremediation of soils polluted with chromium, particularly in supplementation with fertilizers such as farm yard manure and NPK. PMID:25651615

Dheeba, B; Sampathkumar, P; Kannan, K

2014-12-01

328

Risk Factors for Group B Streptococcal Colonization: Potential for Different Transmission Systems by Capsular Type  

PubMed Central

Purpose Group B Streptococcus (GBS) is a common inhabitant of the bowel and vaginal flora, with known transmission routes including sexual contact and vertical transmission from mother to infant. Foodborne transmission is also possible, as GBS is a known fish and bovine pathogen. We conducted a prospective cohort study in order to identify risk factors for acquisition. Methods We identified risk factors for GBS acquisition among college women (n=129) and men (n=128) followed at 3-week intervals for 3 months. Results A doubling in sex acts significantly increased incidence of capsular type V by 80% (95% CI: 1.19, 2.58), and other non-Ia or Ib types combined by 40% (95% CI: 1.00, 2.06; incidence of capsular type Ia (OR=1.2; 95% CI: 0.71, 1.88 p=0.57) and Ib (OR=1.5, 95% CI: 0.75, 2.86, p=0.27) were elevated although not significantly. After adjustment for sexual activity and sexual history, gender, and eating venue, fish consumption increased risk of acquiring capsular types Ia and Ib combined 7.3 fold (95% CI: 2.34, 19.50), but not other capsular types. Beef and milk were not associated with GBS incidence. Conclusions Different GBS capsular types may have different transmission routes. PMID:17689259

Foxman, B.; Gillespie, B. W.; Manning, S. D.; Marrs, C. F.

2007-01-01

329

Digital sleep logs reveal potential impacts of modern temporal structure on class performance in different chronotypes.  

PubMed

Stability of sleep and circadian rhythms are important for healthy learning and memory. While experimental manipulations of lifestyle and learning outcomes present major obstacles, the ongoing increase in data sources allows retrospective data mining of people's sleep timing variation. Here I use digital sleep-log data generated by 1109 students in a biology lab course at the University of Washington to test the hypothesis that higher variance in time asleep and later sleep-onset times negatively correlate with class performance, used here as a real-world proxy for learning and memory. I find that sleep duration variance and mean sleep-onset times both significantly correlate with class performance. These correlations are powerful on weeknights but undetectable on Friday and Saturday nights ("free nights"). Finally, although these data come with no demographic information beyond sex, the constructed demographic groups of "larks" and "owls" within the sexes reveal a significant decrease in performance of owls relative to larks in male students, whereas the correlation of performance with sleep-onset time for all male students was only a near-significant trend. This provides a proof of concept that deeper demographic mining of digital logs in the future may identify subgroups for which certain sleep phenotypes have greater predictive value for performance outcomes. The data analyzed are consistent with known patterns, including sleep-timing delays from weeknights to free nights and sleep-timing delays in men relative to women. These findings support the hypothesis that modern schedule impositions on sleep and circadian timing have consequences for real-world learning and memory. This study also highlights the low-cost, large-scale benefits of personal, daily, digital records as an augmentation of sleep and circadian studies. PMID:25564433

Smarr, Benjamin Lee

2015-02-01

330

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. PMID:23742743

Šponer, Ji?í; Mládek, Arnošt; Špa?ková, Nad’a; Cang, Xiaohui; Cheatham, Thomas E.; Grimme, Stefan

2013-01-01

331

The characteristics of the nematode faunas in subtidal sediments of a large microtidal estuary and nearshore coastal waters differ markedly  

NASA Astrophysics Data System (ADS)

The present study examines traditional paradigms regarding the differences between faunas in estuaries vs coastal waters. The ecological characteristics of the free-living nematode faunas of nearshore, subtidal sediments in downstream and upstream areas of the large, microtidal Swan River Estuary are compared with those similarly recorded seasonally in subtidal sediments along an adjacent part of the coast of temperate south-western Australia. Overall, the nematode species richness recorded in the upstream (38) and downstream estuarine areas (58) and from throughout the estuary (61) were substantially less than in marine waters (75). In addition, the value for Simpson's diversity index was marginally less in the estuary and the dominance of the most abundant species greater. In contrast, the mean nematode species richness and diversity in individual cores followed the reverse trend, reflecting a combination of less variability among the species compositions and far greater densities in the cores from estuarine sediments. Furthermore, the mean density (numbers 10 cm -2) was far higher in both upstream (341) and downstream (903) areas of the estuary than in marine waters (87). Although the compositions of the assemblages in upstream and downstream estuarine areas differed markedly from each other at the species, genus and family levels, these differences were less pronounced than those between either of these areas and marine waters. The trophic compositions at the moderately sheltered and fully exposed marine sites differed from that in both areas of the estuary, whereas that at the most sheltered marine site was similar to that in the downstream estuarine area, with both containing substantial proportions of epistrate-grazing species. The variations among the species richness, diversity, densities and taxonomic and trophic compositions of nematode assemblages in the sediments of the two estuarine areas and nearby marine waters appear to reflect differences in 1) salinity regimes, 2) extents of exposure to wave action and its related effects and 3) amounts and types of food available to nematodes.

Hourston, M.; Potter, I. C.; Warwick, R. M.; Valesini, F. J.

2011-07-01

332

Metal oxide-based nanoparticles: revealing their potential to enhance oil recovery in different wettability systems  

NASA Astrophysics Data System (ADS)

This paper presents systematic studies of hydrophilic metal oxide nanoparticles (NPs) dispersed in brine intended to reveal their potential to enhance oil recovery (EOR) in various rock wettability systems. The stability in suspension (nanofluid) of the NPs has been identified as a key factor related to their use as an EOR agent. Experimental techniques have been developed for nanofluid stability using three coupled methods: direct visual observation, surface conductivity and particle size measurements. The use of a dispersant has been investigated and has been shown to successfully improve metal oxide nanofluid stability as a function of its concentration. The dispersant alters the nanofluid properties, i.e. surface conductivity, pH and particle size distribution. A two-phase coreflood experiment was conducted by injecting the stable nanofluids as a tertiary process (nano-EOR) through core plugs with various wettabilities ranging from water-wet to oil-wet. The combination of metal oxide nanofluid and dispersant improved the oil recovery to a greater extent than either silica-based nanofluid or dispersant alone in all wettability systems. The contact angle, interfacial tension (IFT) and effluent were also measured. It was observed that metal oxide-based nanofluids altered the quartz plates to become more water-wet, and the results are consistent with those of the coreflood experiment. The particle adsorption during the transport process was identified from effluent analysis. The presence of NPs and dispersant reduced the IFT, but its reduction is sufficient to yield significant additional oil recovery. Hence, wettability alteration plays a dominant role in the oil displacement mechanism using nano-EOR.

Hendraningrat, Luky; Torsæter, Ole

2015-02-01

333

Metal oxide-based nanoparticles: revealing their potential to enhance oil recovery in different wettability systems  

NASA Astrophysics Data System (ADS)

This paper presents systematic studies of hydrophilic metal oxide nanoparticles (NPs) dispersed in brine intended to reveal their potential to enhance oil recovery (EOR) in various rock wettability systems. The stability in suspension (nanofluid) of the NPs has been identified as a key factor related to their use as an EOR agent. Experimental techniques have been developed for nanofluid stability using three coupled methods: direct visual observation, surface conductivity and particle size measurements. The use of a dispersant has been investigated and has been shown to successfully improve metal oxide nanofluid stability as a function of its concentration. The dispersant alters the nanofluid properties, i.e. surface conductivity, pH and particle size distribution. A two-phase coreflood experiment was conducted by injecting the stable nanofluids as a tertiary process (nano-EOR) through core plugs with various wettabilities ranging from water-wet to oil-wet. The combination of metal oxide nanofluid and dispersant improved the oil recovery to a greater extent than either silica-based nanofluid or dispersant alone in all wettability systems. The contact angle, interfacial tension (IFT) and effluent were also measured. It was observed that metal oxide-based nanofluids altered the quartz plates to become more water-wet, and the results are consistent with those of the coreflood experiment. The particle adsorption during the transport process was identified from effluent analysis. The presence of NPs and dispersant reduced the IFT, but its reduction is sufficient to yield significant additional oil recovery. Hence, wettability alteration plays a dominant role in the oil displacement mechanism using nano-EOR.

Hendraningrat, Luky; Torsæter, Ole

2014-03-01

334

“Have You Ever Seen This Face?” – Individual Differences and Event-Related Potentials during Deception  

PubMed Central

Deception studies emphasize on the importance of event-related potentials (ERP) for a reliable differentiation of the underlying neuro-cognitive processes. The stimulus-locked parietal P3 amplitude has been shown to reflect stimulus salience but also attentional control available for stimulus processing. Known stimuli requiring truthful responses (targets) and known stimuli requiring deceptive responses (probes) were hypothesized to be more salient than unknown stimuli. Thus, a larger P3 was predicted for known truthful and deceptive stimuli than for unknown stimuli. The Medial Frontal Negativity (MFN) represents the amount of required cognitive control and was expected to be more negative to known truthful and deceptive stimuli than to unknown stimuli. Moreover, we expected higher sensitivity to injustice (SI-perpetrator) and aversiveness (Trait-BIS) to result in more intense neural processes during deception. N?=?102 participants performed a deception task with three picture types: probes requiring deceptive responses, targets requiring truthful responses to known stimuli, and irrelevants being associated with truthful responses to unknown stimuli. Repeated-measures ANOVA and fixed-links modeling suggested a more positive parietal P3 and a more negative frontal MFN to deceptive vs. irrelevant stimuli. Trait-BIS and SI-perpetrator predicted an increase of the P3 and a decrease of the MFN from irrelevants to probes. This suggested an intensification of stimulus salience and cognitive control across picture types in individuals scoring either higher on Trait-BIS or higher on SI-perpetrator. In contrast, individuals with both higher Trait-BIS and higher SI-perpetrator scores showed a less negative probe-MFN suggesting that this subgroup invests less cognitive control to probes. By extending prior research we demonstrate that personality modulates stimulus salience and control processes during deception. PMID:23267339

Leue, Anja; Lange, Sebastian; Beauducel, André

2012-01-01

335

Different calcium sources control somatic versus dendritic SK channel activation during action potentials.  

PubMed

Small-conductance calcium-activated potassium (SK) channels play an important role in regulating neuronal excitability. While SK channels at the soma have long been known to contribute to the medium afterhyperpolarization (mAHP), recent evidence indicates they also regulate NMDA receptor activation in dendritic spines. Here we investigate the activation of SK channels in spines and dendrites of rat cortical pyramidal neurons during action potentials (APs), and compare this to SK channel activation at the soma. Using confocal calcium imaging, we demonstrate that the inhibition of SK channels with apamin results in a location-dependent increase in calcium influx into dendrites and spines during backpropagating APs (average increase, ~40%). This effect was occluded by block of R-type voltage-dependent calcium channels (VDCCs), but not by inhibition of N- or P/Q-type VDCCs, or block of calcium release from intracellular stores. During these experiments, we noticed that the calcium indicator (Oregon Green BAPTA-1) blocked the mAHP. Subsequent experiments using low concentrations of EGTA (1 mm) produced the same result, suggesting that somatic SK channels are not tightly colocalized with their calcium source. Consistent with this idea, all known subtypes of VDCCs except R-type were calcium sources for the apamin-sensitive mAHP at the soma. We conclude that SK channels in spines and dendrites of cortical pyramidal neurons regulate calcium influx during backpropagating APs in a distance-dependent manner, and are tightly coupled to R-type VDCCs. In contrast, SK channels activated by APs at the soma of these neurons are weakly coupled to a variety of VDCCs. PMID:24336706

Jones, Scott L; Stuart, Greg J

2013-12-11

336

The potential risk assessment for different arsenic species in the aquatic environment.  

PubMed

The different toxicity characteristics of arsenic species result in discrepant ecological risk. The predicted no-effect concentrations (PNECs) 43.65, 250.18, and 2.00×10(3)?g/L were calculated for As(III), As(V), and dimethylarsinic acid in aqueous phase, respectively. With these PNECs, the ecological risk from arsenic species in Pearl River Delta in China and Kwabrafo stream in Ghana was evaluated. It was found that the risk from As(III) and As(V) in the samples from Pearl River Delta was low, while much high in Kwabrafo stream. This study implies that ecological risk of arsenic should be evaluated basing on its species. PMID:25597657

Du, Meng; Wei, Dongbin; Tan, Zhuowei; Lin, Aiwu; Du, Yuguo

2015-01-01

337

Modeling a Cortical Auxin Maximum for Nodulation: Different Signatures of Potential Strategies  

PubMed Central

Lateral organ formation from plant roots typically requires the de novo creation of a meristem, initiated at the location of a localized auxin maximum. Legume roots can form both root nodules and lateral roots. From the basic principles of auxin transport and metabolism only a few mechanisms can be inferred for increasing the local auxin concentration: increased influx, decreased efflux, and (increased) local production. Using computer simulations we investigate the different spatio-temporal patterns resulting from each of these mechanisms in the context of a root model of a generalized legume. We apply all mechanisms to the same group of preselected cells, dubbed the controlled area. We find that each mechanism leaves its own characteristic signature. Local production by itself can not create a strong auxin maximum. An increase of influx, as is observed in lateral root formation, can result in an auxin maximum that is spatially more confined than the controlled area. A decrease of efflux on the other hand leads to a broad maximum, which is more similar to what is observed for nodule primordia. With our prime interest in nodulation, we further investigate the dynamics following a decrease of efflux. We find that with a homogeneous change in the whole cortex, the first auxin accumulation is observed in the inner cortex. The steady state lateral location of this efflux reduced auxin maximum can be shifted by slight changes in the ratio of central to peripheral efflux carriers. We discuss the implications of this finding in the context of determinate and indeterminate nodules, which originate from different cortical positions. The patterns we have found are robust under disruption of the (artificial) tissue layout. The same patterns are therefore likely to occur in many other contexts. PMID:22654886

Deinum, Eva Elisabeth; Geurts, René; Bisseling, Ton; Mulder, Bela M.

2012-01-01

338

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

339

Comparison of Large Aperture Scintillometer and Eddy Covariance Measurements: Can Thermal Infrared Data Be Used to Capture Footprint-Induced Differences?  

Microsoft Academic Search

Eddy covariance (EC) and large aperture scintillometer (LAS) measurements were collected over an irrigated olive orchard near Marrakech, Morocco. The tall, sparse vegetation in the experimental site was relatively homogeneous, but during irrigation events spatial variability in soil humidity was large. This heterogeneity caused large differences between the source area characteristics of the EC system and the LAS, resulting in

J. C. B. Hoedjes; A. Chehbouni; J. Ezzahar; R. Escadafal; H. A. R. de Bruin

2007-01-01

340

Potential of Thlaspi caerulescens for Cadmium Phytoremediation: Comparison of Two Representative Soil Types in Japan under Different Planting Frequencies  

Microsoft Academic Search

To assess the potential of the Cd hyperaccumulator Thlaspi caerulescens (Ganges ecotype) for Cd phytoremediation in Japan, we compared the changes in the soil Cd concentration between a Fluvisol and an Andosol and the efficiency of Cd removal under different planting frequencies in a pot experiment. The soils were artificially contaminated with Cd(NO3)2 to the level of about 5 mg

Yuko Nishiyama; Junta Yanai; Takashi Kosaki

2005-01-01

341

Age and sex-related differences in brainstem auditory evoked potentials in secondary school students living in Northern European Russia  

Microsoft Academic Search

Brainstem auditory evoked potentials (BAEPs) were studied in 46 1st- to 11th-year students (22 boys and 24 girls) of a rural\\u000a secondary school in Arkhangel’sk oblast. The objective of this work was to study age- and sex-related differences in BAEP\\u000a characteristics in children and adolescents, living in the North and assess the BAEP characteristics as compared to reference\\u000a values. In

V. P. Rozhkov; S. I. Soroko

2009-01-01

342

Discussion on the Energy-Saving Potential of a Hybrid System in a Large Space Building in Different Areas  

E-print Network

The use of a hybrid ventilation system is promoted to decrease the annual energy consumption of air conditioning. The switch-point of temperature, which is related with weather conditions, is presented to control the hybrid system properly...

Liu, S.; Huang, C.

2006-01-01

343

High order numerical simulation of the transmission and scattering of waves using the method of difference potentials  

NASA Astrophysics Data System (ADS)

The method of difference potentials generalizes the method of Calderon's operators from PDEs to arbitrary difference equations and systems. It offers several key advantages, such as the capability of handling boundaries/interfaces that are not aligned with the discretization grid, variable coefficients, and nonstandard boundary conditions. In doing so, the complexity of the algorithm remains comparable to that of an ordinary finite difference scheme on a regular structured grid. Previously, we have applied the method of difference potentials to solving several variable coefficient interior Helmholtz problems with fourth and sixth order accuracy. We have employed compact finite difference schemes as a core discretization methodology. Those schemes enable high order accuracy on narrow stencils and hence require only as many boundary conditions as needed for the underlying differential equation itself. Numerical experiments corroborate the high order accuracy of our method for variable coefficients, regular grids, and non-conforming boundaries. In the current paper, we extend the previously developed methodology to exterior problems. We present a complete theoretical analysis of the algorithm, as well as the results of a series of numerical simulations. Specifically, we study the scattering of time-harmonic waves about smooth shapes, subject to various boundary conditions. We also solve the transmission/scattering problems, in which not only do the waves scatter off a given shape but also propagate through the interface and travel across the heterogeneous medium inside. In all the cases, our methodology guarantees high order accuracy for regular grids and non-conforming boundaries and interfaces.

Medvinsky, M.; Tsynkov, S.; Turkel, E.

2013-06-01

344

Differences in the dynamics and potential production of impounded and unimpounded white sturgeon populations in the lower Columbia River  

SciTech Connect

White sturgeons Acipenser transmontanus were sampled in three lower Columbia River reservoirs from 1987 to 1991 to describe population dynamics, the ability of these stocks to sustain harvest, and differences among reservoir and unimpounded populations. Significant differences were observed among reservoirs in white sturgeon abundance, biomass, size composition, sex ratio, size of females at maturity, growth rate, condition factor, and rate of exploitation. No differences among reservoirs were detected in fecundity, natural mortality rate, or longevity, in part because of sampling difficulties. Recruitment rates and densities in reservoirs were inversely correlated with growth rate, condition factor, and size of females at maturity. Differences in population dynamics resulted in substantial differences in sustainable yields. Maximum yields per recruit were predicted at annual exploitation rates between 5 and 15%. Most characteristics of reservoir populations were less than or equal to optima reported for the unimpounded lower river; as a result, yield per recruit, reproductive potential per recruit, and the number of recruits were less in reservoirs than in the unimpounded river. Comparisons with pristine standing stocks suggest that the unimpounded river may approximate preimpoundment conditions for white sturgeon. We conclude that potential yield from impounded populations has been reduced by dam construction, which restricts populations to river segments that may not include conditions optimal for all life stages. Alternatives for enchancement of reservoir populations might include improved passage at dams, increased spring flow to improve spawning success, transplants from productive populations, hatchery supplementation, and more intensive harvest management. 54 refs., 7 figs., 7 tabs.

Beamesderfer, R.C.P.; Rien, T.A.; Nigro, A.A. [Oregon Department of Fish and Wildlife, Clackamas, OR (United States)

1995-11-01

345

Limited waterborne acute toxicity of native polycyclic aromatic compounds from coals of different types compared to their total hazard potential.  

PubMed

Coals contain native polycyclic aromatic compounds (PACs), which include polycyclic aromatic hydrocarbons (PAHs), and heterocyclic aromatic compounds (NSO-PACs) in considerably varying amounts up to 2500 mg/kg. Whereas PAC bioavailability and toxicity from coals are generally considered to be low, few studies have considered potential variations arising from the composition of different coal types including native PAC content. In the present study, fine particles of different coal types exhibiting variable properties were systematically investigated regarding their PAC bioavailability. PAH content reached up to 79 mg/kg EPA-PAH and 865 mg/kg total PAH. Determination of the toxic potential of extracted PACs in bioassays showed inhibition of Caenorhabditis elegans reproduction (up to 94%) and increased mortality of Danio rerio embryos (up to 100%) after exposure to extracts from lignite, sub-bituminous, and bituminous coals. Anthracite extracts showed no effects. Contact assays using whole coal samples revealed no toxicity to D. rerio embryos in any of the coal samples, suggesting low bioavailability of PACs. In contrast, C. elegans reproduction was inhibited by direct coal contact; however, the observed toxicity probably resulted from other coal effects. The results suggest that despite the high toxic potential of PACs present, their bioavailability from different coal types is very limited and independent of coal properties and native PAH content. PMID:24024738

Meyer, Wiebke; Seiler, Thomas-Benjamin; Reininghaus, Mathias; Schwarzbauer, Jan; Püttmann, Wilhelm; Hollert, Henner; Achten, Christine

2013-10-15

346

Job Stress in the United Kingdom: Are Small and Medium-Sized Enterprises and Large Enterprises Different?  

PubMed

This paper examines the relationships between firm size and employees' experience of work stress. We used a matched employer-employee dataset (Workplace Employment Relations Survey 2011) that comprises of 7182 employees from 1210 private organizations in the United Kingdom. Initially, we find that employees in small and medium-sized enterprises experience lower level of overall job stress than those in large enterprises, although the effect disappears when we control for individual and organizational characteristics in the model. We also find that quantitative work overload, job insecurity and poor promotion opportunities, good work relationships and poor communication are strongly associated with job stress in the small and medium-sized enterprises, whereas qualitative work overload, poor job autonomy and employee engagements are more related with larger enterprises. Hence, our estimates show that the association and magnitude of estimated effects differ significantly by enterprise size. Copyright © 2013 John Wiley & Sons, Ltd. PMID:24302431

Lai, Yanqing; Saridakis, George; Blackburn, Robert

2013-12-01

347

Differences in the neural mechanisms of selective attention in children from different socioeconomic backgrounds: An event-related brain potential study  

PubMed Central

Previous research indicates that children from lower socioeconomic backgrounds show deficits in aspects of attention, including a reduced ability to filter irrelevant information and to suppress prepotent responses. However, less is known about the neural mechanisms of group differences in attention, which could reveal the stages of processing at which attention deficits arise. The present study examined this question using an event-related brain potential (ERP) measure of selective auditory attention. Thirty-two children aged 3- to 8-years participated in the study. Children were cued to attend selectively to one of two simultaneously presented narrative stories. The stories differed in location (left/right speaker), narration voice (male/female), and content. ERPs were recorded to linguistic and non-linguistic probe stimuli embedded in the attended and unattended stories. Children whose mothers had lower levels of educational attainment (no college experience) showed reduced effects of selective attention on neural processing relative to children whose mothers had higher levels of educational attainment (at least some college). These differences occurred by 100 msec after probe onset. Furthermore, the differences were related specifically to a reduced ability to filter irrelevant information (i.e., to suppress the response to sounds in the unattended channel) among children whose mothers had lower levels of education. These data provide direct evidence for differences in the earliest stages of processing within neural systems mediating selective attention in children from different socioeconomic backgrounds. Results are discussed in the context of intervention programs aimed at improving attention and self-regulation abilities in children at-risk for school failure. PMID:19635089

Stevens, Courtney; Lauinger, Brittni; Neville, Helen

2009-01-01

348

Regional differences in glycoconjugates of intestinal M cells in mice: potential targets for mucosal vaccines.  

PubMed

We have used a panel of lectins and antibodies to describe the composition of complex carbohydrates associated with M cells in various regions of the intestinal tract of adult BALB/c mice. The fucose-specific lectin Ulex europaeus agglutinin type I (UEA I) is a marker of M cells in the small intestine and recognized M cells at an early stage of differentiation. Subpopulations of M cells in a single follicle-associated epithelium (FAE) could be distinguished by different fucose-specific probes. Certain lectins revealed that M cells have basal processes that extend into the underlying lymphoid tissue. Colonic and rectal M cells display glycosylation patterns distinct from M cells of Peyer's patches and are characterized by terminal galactose. UEA I selectively adhered to Peyer's patch M cells in mucosal explants and in ligated intestinal loops in vivo. The lectin was taken up into endocytic vesicles and transported to the intra-epithelial pocket and other domains of the basolateral membrane. Thus M cell-specific glycoconjugates could serve as "receptors" for targeting of lectin-antigen conjugates to the mucosal immune system. PMID:7810658

Giannasca, P J; Giannasca, K T; Falk, P; Gordon, J I; Neutra, M R

1994-12-01

349

Occurrence and potential health risk of Cryptosporidium and Giardia in different water catchments in Belgium.  

PubMed

Human wastewater and livestock can contribute to contamination of surface water with Cryptosporidium and Giardia. In countries where a substantial proportion of drinking water is produced from surface water, e.g., Belgium, this poses a constant threat on drinking water safety. Our objective was to monitor the presence of Cryptosporidium and Giardia in different water catchment sites in Belgium and to discriminate between (oo)cysts from human or animal origin using genotyping. Monthly samples were collected from raw water and purified drinking water at four catchment sites. Cryptosporidium and Giardia were detected using USEPA method 1623 and positive samples were genotyped. No contamination was found in purified water at any site. In three catchments, only low numbers of (oo)cysts were recovered from raw water samples (<1/liter), but raw water samples from one catchment site were frequently contaminated with Giardia (92 %) and Cryptosporidium (96 %), especially in winter and spring. Genotyping of Giardia in 38 water samples identified the presence of Giardia duodenalis assemblage AI, AII, BIV, BIV-like, and E. Cryptosporidium andersoni, Cryptosporidium suis, Cryptosporidium horse genotype, Cryptosporidium parvum, and Cryptosporidium hominis were detected. The genotyping results suggest that agriculture may be a more important source of surface water contamination than human waste in this catchment. In catchment sites with contaminated surface water, such as the Blankaart, continuous monitoring of treated water for the presence of Cryptosporidium and Giardia would be justified and (point) sources of surface water contamination should be identified. PMID:25616782

Ehsan, Amimul; Geurden, Thomas; Casaert, Stijn; Paulussen, Jef; De Coster, Lut; Schoemaker, Toon; Chalmers, Rachel; Grit, Grietje; Vercruysse, Jozef; Claerebout, Edwin

2015-02-01

350

Gender differences in methionine accumulation and metabolism in freshly isolated mouse hepatocytes: Potential roles in toxicity  

SciTech Connect

L-Methionine (Met) is hepatotoxic at high concentrations. Because Met toxicity in freshly isolated mouse hepatocytes is gender-dependent, the goal of this study was to assess the roles of Met accumulation and metabolism in the increased sensitivity of male hepatocytes to Met toxicity compared with female hepatocytes. Male hepatocytes incubated with Met (30 mM) at 37 {sup o}C exhibited higher levels of intracellular Met at 0.5, 1.0, and 1.5 h, respectively, compared to female hepatocytes. Conversely, female hepatocytes had higher levels of S-adenosyl-L-methionine compared to male hepatocytes. Female hepatocytes also exhibited higher L-methionine-L-sulfoxide levels relative to control hepatocytes, whereas the increases in L-methionine-D-sulfoxide (Met-D-O) levels were similar in hepatocytes of both genders. Addition of aminooxyacetic acid (AOAA), an inhibitor of Met transamination, significantly increased Met levels at 1.5 h and increased Met-D-O levels at 1.0 and 1.5 h only in Met-exposed male hepatocytes. No gender differences in cytosolic Met transamination activity by glutamine transaminase K were detected. However, female mouse liver cytosol exhibited higher methionine-DL-sulfoxide (MetO) reductase activity than male mouse liver cytosol at low (0.25 and 0.5 mM) MetO concentrations. Collectively, these results suggest that increased cellular Met accumulation, decreased Met transmethylation, and increased Met and MetO transamination in male mouse hepatocytes may be contributing to the higher sensitivity of the male mouse hepatocytes to Met toxicity in comparison with female mouse hepatocytes.

Dever, Joseph T. [Department of Comparative Biosciences and Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, Wisconsin (United States); Elfarra, Adnan A. [Department of Comparative Biosciences and Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, Wisconsin (United States)], E-mail: aelfarra@wisc.edu

2009-05-01

351

Effects of different culture conditions on biological potential and metabolites production in three Penicillium isolates.  

PubMed

Abstract The genus Penicillium is well known for its importance in drug and food production. Certain species are produced on an industrial scale for the production of antibiotics (e.g. penicillin) or for insertion in food (e.g. cheese). In the present work, three Penicillium species, part of the natural mycobiota growing on various food products were selected - P. ochrochloron, P. funiculosum and P. verrucosum var. cyclopium. The objective of our study was to value these species from the point of view of production of bioactive metabolites. The species were obtained after inoculation and growth in Czapek and Malt media. Both mycelia and culture media were analyzed to monitor the production of different metabolites by each fungus and their release to the culture medium. The concentrations of sugars, organic acids, phenolic acids and tocopherols were determined. Antioxidant activity of the phenolic extracts was evaluated, as also the antimicrobial activity of phenolic acids, organic acids and tocopherols extracts. Rhamnose, xylose, fructose and trehalose were found in all the mycelia and culture media; the prevailing organic acids were oxalic and fumaric acids, and protocatechuic and p-hydroxybenzoic acids were the most common phenolic acids; ?-tocopherol was the most abundant vitamin E isoform. Generally, the phenolic extracts corresponding to the mycelia samples revealed higher antioxidant activity. Concerning the antimicrobial activity there were some fluctuations, however all the studied species revealed activity against the tested strains. Therefore, the in-vitro bioprocesses can be an alternative for the production of bioactive metabolites that can be used by pharmaceutical industry. PMID:24261405

Reis, Filipa S; ?iri?, Ana; Stojkovi?, Dejan; Barros, Lillian; Ljaljevi?-Grbi?, Milica; Sokovi?, Marina; Ferreira, Isabel C F R

2015-02-01

352

Recruitment potential of two perennial grasses with different growth forms at a semiarid-arid transition zone.  

PubMed

The objective of this study was to quantify differences in recruitment potential (seed production, seed presence in the soil) for two congeneric perennial grasses (Bouteloua gracilis, Bouteloua eriopoda [Poaceae]) that dominate adjacent arid and semiarid grassland biomes. It was hypothesized that these species have different recruitment strategies at the biome transition zone that are related to differences in their growth form and longevity. Recruitment potential for each Bouteloua species was compared in patches dominated by one or both species or codominated by the invasive shrub, Larrea tridentata (Zygophyllaceae). Regional variation in recruitment was examined for B. gracilis for cases in which comparable data were available in the literature for a site located within the semiarid grassland biome. The short-lived stoloniferous species B. eriopoda produced more seeds per plant than the long-lived bunchgrass B. gracilis, yet seed viability (<60%) and presence in the soil were lower. Mean viability of B. gracilis was higher (>90%) than that of B. eriopoda, and a greater percentage of seeds produced on a square meter basis was found in the soil (10-25%). Similar patterns were found for both species in all grass-dominated patches. Bouteloua eriopoda plants growing in patches codominated by L. tridentata produced fewer seeds per plant with lower viability, and fewer seeds were found in the soil compared to grass-dominated patches. Regional comparisons found greater seed production per square meter and more seeds in the soil for B. gracilis at the transitional site compared with a cooler, wetter site located within the semiarid grassland biome. These differences in recruitment potential along with published differences in rates of seedling establishment and vegetative spread may explain, at least in part, localized patterns in species dominance. PMID:21665589

Peters, Debra P C

2002-10-01

353

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

354

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. PMID:22802956

Ajemian, Matthew J.; Powers, Sean P.; Murdoch, Thaddeus J. T.

2012-01-01

355

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

356

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

357

Brain potentials to native phoneme discrimination reveal the origin of individual differences in learning the sounds of a second language  

PubMed Central

Human beings differ in their ability to master the sounds of their second language (L2). Phonetic training studies have proposed that differences in phonetic learning stem from differences in psychoacoustic abilities rather than speech-specific capabilities. We aimed at finding the origin of individual differences in L2 phonetic acquisition in natural learning contexts. We consider two alternative explanations: a general psychoacoustic origin vs. a speech-specific one. For this purpose, event-related potentials (ERPs) were recorded from two groups of early, proficient Spanish-Catalan bilinguals who differed in their mastery of the Catalan (L2) phonetic contrast /e-?/. Brain activity in response to acoustic change detection was recorded in three different conditions involving tones of different length (duration condition), frequency (frequency condition), and presentation order (pattern condition). In addition, neural correlates of speech change detection were also assessed for both native (/o/-/e/) and nonnative (/o/-/ö/) phonetic contrasts (speech condition). Participants' discrimination accuracy, reflected electrically as a mismatch negativity (MMN), was similar between the two groups of participants in the three acoustic conditions. Conversely, the MMN was reduced in poor perceivers (PP) when they were presented with speech sounds. Therefore, our results support a speech-specific origin of individual variability in L2 phonetic mastery. PMID:18852470

Díaz, Begoña; Baus, Cristina; Escera, Carles; Costa, Albert; Sebastián-Gallés, Núria

2008-01-01

358

Modeling of region-specific fMRI BOLD neurovascular response functions in rat brain reveals residual differences that correlate with the differences in regional evoked potentials  

PubMed Central

The response of the rat visual system to flashes of blue light has been studied by blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI). The BOLD temporal response is dependent on the number of flashes presented and demonstrates a refractory period that depends on flash frequency. Activated brain regions included the primary and secondary visual cortex, superior colliculus (SC), dorsal Lateral Geniculate (DLG), and Lateral Posterior Nucleus (LP), which were found to exhibit differing temporal responses. To explain these differences, the BOLD neurovascular response function was modeled. A second order differential equation was developed and solved numerically to arrive at region-specific response functions. Included in the model are the light input from the diode (duty cycle), a refractory period, a transient response following onset and cessation of stimulus, and a slow adjustment to changes in the average level of the signal. Constants in the differential equation were evaluated for each region by fitting the model to the experimental BOLD response from a single flash, and the equation was then solved for multiple flashes. The simulation mimics the major features of the data; however, remaining differences in the frequency dependence of the response between the cortical and subcortical regions were unexplained. We hypothesized that these discrepancies were due to regional-specific differences in neuronal response to flash frequency. To test this hypothesis, cortical visual evoked potentials (VEPs) were recorded using the same stimulation protocol as the fMRI. Cortical VEPs were more suppressed than subcortical VEPs as flash frequency increased, supporting our hypothesis. This is the first report that regional differences in neuronal activation to the same stimulus lead to differential BOLD activation. PMID:18406628

Pawela, Christopher P.; Hudetz, Anthony G.; Ward, B. Douglas; Schulte, Marie L.; Li, Rupeng; Kao, Dennis S.; Mauck, Matthew C.; Cho, Younghoon R.; Neitz, Jay; Hyde, James S.

2008-01-01

359

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

360

Plant Growth Promotion Potential Is Equally Represented in Diverse Grapevine Root-Associated Bacterial Communities from Different Biopedoclimatic Environments  

PubMed Central

Plant-associated bacteria provide important services to host plants. Environmental factors such as cultivar type and pedoclimatic conditions contribute to shape their diversity. However, whether these environmental factors may influence the plant growth promoting (PGP) potential of the root-associated bacteria is not widely understood. To address this issue, the diversity and PGP potential of the bacterial assemblage associated with the grapevine root system of different cultivars in three Mediterranean environments along a macrotransect identifying an aridity gradient were assessed by culture-dependent and independent approaches. According to 16S rRNA gene PCR-DGGE, the structure of endosphere and rhizosphere bacterial communities was highly diverse (P = 0.03) and was associated with a cultivar/latitudinal/climatic effect. Despite being diverse, the bacterial communities associated with Egyptian grapevines shared a higher similarity with the Tunisian grapevines than those cultivated in North Italy. A similar distribution, according to the cultivar/latitude/aridity gradients, was observed for the cultivable bacteria. Many isolates (23%) presented in vitro multiple stress resistance capabilities and PGP activities, the most frequent being auxin synthesis (82%), insoluble phosphate solubilisation (61%), and ammonia production (70%). The comparable numbers and types of potential PGP traits among the three different environmental settings indicate a strong functional homeostasis of beneficial bacteria associated with grape root. PMID:23878810

Fusi, Marco; Cherif, Ameur; Abou-Hadid, Ayman; El-Bahairy, Usama; Sorlini, Claudia; Daffonchio, Daniele

2013-01-01

361

Identification of Candida albicans by using different culture medias and its association in potentially malignant and malignant lesions  

PubMed Central

Background and Objective: The present study evaluates the association of Candida albicans with normal control group, potentially malignant and malignant lesions of oral cavity by using two different liquid culture media. Materials and Methods: Saliva was collected and biopsy was taken only from those clinically suspected potentially malignant and malignant lesions for histopathological diagnosis. Saliva samples were inoculated for fungal growth in Sabouraud's dextrose agar and culture-positive samples had undergone for Germ tube test. Germ tube-positive samples were further taken for quantification of chlamydospore production in liquid media at 8 and 16 hours. Results: In normal control groups no fungus growth was found; however, potentially malignant and malignant cases showed fungus growth, positive germ tube test and chlamydospore formation. The result also showed rapid and quantitatively more chlamydospore formation in corn meal broth + 5% milk in comparison to serum milk culture media. Conclusion: The oral mucosa is compromised in potentially malignant lesions, it can be argued that this species may be involved in carcinogenesis by elaborating the nitrosamine compounds which either act directly on oral mucosa or interact with other chemical carcinogens to activate specific proto-oncogenes and thereby initiate oral neoplasia. PMID:22090762

Saigal, Sonal; Bhargava, Ankur; Mehra, S. K.; Dakwala, Falguni

2011-01-01

362

EFM data mapped into 2D images of tip-sample contact potential difference and capacitance second derivative  

NASA Astrophysics Data System (ADS)

We report a simple technique for mapping Electrostatic Force Microscopy (EFM) bias sweep data into 2D images. The method allows simultaneous probing, in the same scanning area, of the contact potential difference and the second derivative of the capacitance between tip and sample, along with the height information. The only required equipment consists of a microscope with lift-mode EFM capable of phase shift detection. We designate this approach as Scanning Probe Potential Electrostatic Force Microscopy (SPP-EFM). An open-source MATLAB Graphical User Interface (GUI) for images acquisition, processing and analysis has been developed. The technique is tested with Indium Tin Oxide (ITO) and with poly(3-hexylthiophene) (P3HT) nanowires for organic transistor applications.

Lilliu, S.; Maragliano, C.; Hampton, M.; Elliott, M.; Stefancich, M.; Chiesa, M.; Dahlem, M. S.; MacDonald, J. E.

2013-11-01

363

EFM data mapped into 2D images of tip-sample contact potential difference and capacitance second derivative.  

PubMed

We report a simple technique for mapping Electrostatic Force Microscopy (EFM) bias sweep data into 2D images. The method allows simultaneous probing, in the same scanning area, of the contact potential difference and the second derivative of the capacitance between tip and sample, along with the height information. The only required equipment consists of a microscope with lift-mode EFM capable of phase shift detection. We designate this approach as Scanning Probe Potential Electrostatic Force Microscopy (SPP-EFM). An open-source MATLAB Graphical User Interface (GUI) for images acquisition, processing and analysis has been developed. The technique is tested with Indium Tin Oxide (ITO) and with poly(3-hexylthiophene) (P3HT) nanowires for organic transistor applications. PMID:24284731

Lilliu, S; Maragliano, C; Hampton, M; Elliott, M; Stefancich, M; Chiesa, M; Dahlem, M S; Macdonald, J E

2013-01-01

364

EFM data mapped into 2D images of tip-sample contact potential difference and capacitance second derivative  

PubMed Central

We report a simple technique for mapping Electrostatic Force Microscopy (EFM) bias sweep data into 2D images. The method allows simultaneous probing, in the same scanning area, of the contact potential difference and the second derivative of the capacitance between tip and sample, along with the height information. The only required equipment consists of a microscope with lift-mode EFM capable of phase shift detection. We designate this approach as Scanning Probe Potential Electrostatic Force Microscopy (SPP-EFM). An open-source MATLAB Graphical User Interface (GUI) for images acquisition, processing and analysis has been developed. The technique is tested with Indium Tin Oxide (ITO) and with poly(3-hexylthiophene) (P3HT) nanowires for organic transistor applications. PMID:24284731

Lilliu, S.; Maragliano, C.; Hampton, M.; Elliott, M.; Stefancich, M.; Chiesa, M.; Dahlem, M. S.; Macdonald, J. E.

2013-01-01

365

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

366

Large-Scale Expression Analysis Reveals Distinct MicroRNA Profiles at Different Stages of Human Neurodevelopment  

PubMed Central

Background MicroRNAs (miRNAs) are short non-coding RNAs predicted to regulate one third of protein coding genes via mRNA targeting. In conjunction with key transcription factors, such as the repressor REST (RE1 silencing transcription factor), miRNAs play crucial roles in neurogenesis, which requires a highly orchestrated program of gene expression to ensure the appropriate development and function of diverse neural cell types. Whilst previous studies have highlighted select groups of miRNAs during neural development, there remains a need for amenable models in which miRNA expression and function can be analyzed over the duration of neurogenesis. Principal Findings We performed large-scale expression profiling of miRNAs in human NTera2/D1 (NT2) cells during retinoic acid (RA)-induced transition from progenitors to fully differentiated neural phenotypes. Our results revealed dynamic changes of miRNA patterns, resulting in distinct miRNA subsets that could be linked to specific neurodevelopmental stages. Moreover, the cell-type specific miRNA subsets were very similar in NT2-derived differentiated cells and human primary neurons and astrocytes. Further analysis identified miRNAs as putative regulators of REST, as well as candidate miRNAs targeted by REST. Finally, we confirmed the existence of two predicted miRNAs; pred-MIR191 and pred-MIR222 associated with SLAIN1 and FOXP2, respectively, and provided some evidence of their potential co-regulation. Conclusions In the present study, we demonstrate that regulation of miRNAs occurs in precise patterns indicative of their roles in cell fate commitment, progenitor expansion and differentiation into neurons and glia. Furthermore, the similarity between our NT2 system and primary human cells suggests their roles in molecular pathways critical for human in vivo neurogenesis. PMID:20559549

Zhang, Dongling; Ly, Dao; McKinnell, Iain; Walker, P. Roy; Sikorska, Marianna

2010-01-01

367

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 (137Cs) 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 137Cs from plastic laminate and vinyl flooring (93.4-96.8%) but were not effective for removing 137Cs 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 137Cs 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

368

The generalized spin-boson model for electron-transfer reactions involving two harmonic potentials with a different force constant  

SciTech Connect

The generalized spin-model is employed to analyze the electron-transfer reactions involving two harmonic potentials with a different force constant. An analytical expression for the nonadiabatic rate constant is derived with fill consideration of the effects of quantum modes. For a single dominant solvent mode at low frequency, the result of the high temperature regime is reduced to the formula derived earlier based on the stochastic Liouville theory. For multiple soft solvent modes, the rate constant is a convoluted integral of a rate function for each individual single mode.

Tang, J.

1994-01-01

369

Effect of natural maize phytochemicals on Aspergillus section Flavi sclerotia characteristics under different conditions of growth media and water potential  

Microsoft Academic Search

The effects of the natural phytochemicals trans-cinnamic acid (CA) and ferulic acid (FA) at concentrations of 1–20mM (CA) and 1–25mM (FA) on sclerotial production by Aspergillus flavus and Aspergillus parasiticus were evaluated. Studies on sclerotium number and size were carried out in different growth media and water potentials (MPa). High concentrations of CA (20mM, ?0.75MPa; 10mM, ?3.5MPa) and FA (10,

A. Nesci; M. Etcheverry

2009-01-01

370

Use of different organic wastes in reducing the potential leaching of propanil, isoxaben, cadusafos and pencycuron through the soil.  

PubMed

In this study, we examined the effect of four different organic wastes (OW)-composted sheep manure (CSM), spent coffee grounds (SCG), composted pine bark (CPB) and coir (CR)-on the potential groundwater pollution of propanil and isoxaben (herbicides), cadusafos (insecticide) and pencycuron (fungicide) under laboratory conditions. For this purpose, leaching studies were conducted using disturbed soil columns filled with a clay loam soil (Hipercalcic calcisol). The addition of organic matter (OM) drastically reduced the movement of the studied pesticides. The results obtained point to the interest in the use of agro-industrial and composted OW in reducing the groundwater pollution by pesticide drainage. PMID:24901963

Fenoll, José; Garrido, Isabel; Hellín, Pilar; Flores, Pilar; Vela, Nuria; Navarro, Simón

2014-01-01

371

Cell line differences in replication timing of human glutamate receptor genes and other large genes associated with neural disease.  

PubMed

There is considerable current interest in the function of epigenetic mechanisms in neuroplasticity with regard to learning and memory formation and to a range of neural diseases. Previously, we described replication timing on human chromosome 21q in the THP-1 human cell line (2n = 46, XY) and showed that several genes associated with neural diseases, such as the neuronal glutamate receptor subunit GluR-5 (GRIK1) and amyloid precursor protein (APP), were located in regions where replication timing transitioned from early to late S phase. Here, we compared replication timing of all known human glutamate receptor genes (26 genes in total) and APP in 6 different human cell lines including human neuron-related cell lines. Replication timings were obtained by integrating our previously reported data with new data generated here and information from the online database ReplicationDomain. We found that many of the glutamate receptor genes were clearly located in replication timing transition zones in neural precursor cells, but this relationship was less clear in embryonic stem cells before neural differentiation; in the latter, the genes were often located in later replication timing zones that displayed DNA hypermethylation. Analysis of selected large glutamate receptor genes (>200 kb), and of APP, showed that their precise replication timing patterns differed among the cell lines. We propose that the transition zones of DNA replication timing are altered by epigenetic mechanisms, and that these changes may affect the neuroplasticity that is important to memory and learning, and may also have a role in the development of neural diseases. PMID:25437050

Watanabe, Yoshihisa; Shibata, Kiyoshi; Maekawa, Masato

2014-10-01

372

Simultaneous projection and detection system of four different frequencies for microwave imaging reflectometry in Large Helical Device  

SciTech Connect

A simultaneous projection/detection system of four different frequencies for microwave imaging reflectometry (MIR) was developed for three-dimensional observation of electron density fluctuations in the Large Helical Device (LHD). The microwave with four frequency components at 60.410, 61.808, 63.008, and 64.610 GHz is projected in a continuous-wave mode to illuminate the target LHD plasma. A two-dimensional horn-antenna mixer array (2D HMA) receives the reflected wave from the plasma as well as the wave from the local oscillator operating at 55.800 GHz. The first intermediate frequency (IF) signals at 4.610, 6.008, 7.208, and 8.810 GHz were confirmed to be obtained by downconversion of these microwaves using the 2D HMA. Each of these first IF components is filtered from each other and downconverted again for the superheterodyne detection. It was confirmed that both the amplitudes and the phases of the detected signals reflect the fluctuations in LHD plasmas.

Yoshinaga, T.; Nagayama, Y.; Tsuchiya, H. [National Institute for Fusion Science, 322-6 Oroshi, Toki 509-5292 (Japan); Kuwahara, D.; Tsuji-Iio, S. [Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8550 (Japan); Yamaguchi, S. [Kansai University, 3-3-35 Yamate, Suita 564-8680 (Japan); Kogi, Y. [Fukuoka Institute of Technology, 3-30-1 Wajiro-Higashi, Fukuoka 811- 0295 (Japan); Mase, A. [Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8680 (Japan)

2010-10-15

373

Simultaneous projection and detection system of four different frequencies for microwave imaging reflectometry in Large Helical Device.  

PubMed

A simultaneous projection/detection system of four different frequencies for microwave imaging reflectometry (MIR) was developed for three-dimensional observation of electron density fluctuations in the Large Helical Device (LHD). The microwave with four frequency components at 60.410, 61.808, 63.008, and 64.610 GHz is projected in a continuous-wave mode to illuminate the target LHD plasma. A two-dimensional horn-antenna mixer array (2D HMA) receives the reflected wave from the plasma as well as the wave from the local oscillator operating at 55.800 GHz. The first intermediate frequency (IF) signals at 4.610, 6.008, 7.208, and 8.810 GHz were confirmed to be obtained by downconversion of these microwaves using the 2D HMA. Each of these first IF components is filtered from each other and downconverted again for the superheterodyne detection. It was confirmed that both the amplitudes and the phases of the detected signals reflect the fluctuations in LHD plasmas. PMID:21033947

Yoshinaga, T; Nagayama, Y; Kuwahara, D; Tsuchiya, H; Yamaguchi, S; Kogi, Y; Tsuji-Iio, S; Mase, A

2010-10-01

374

Phenotypic differences in a large family with Kennedy's disease from the Middle Black Sea region of Turkey.  

PubMed

We report the clinical and electrophysiological features of a large Turkish family with genetically confirmed X-linked spinal and bulbar muscular atrophy (SBMA). Family members were identified by field work. A detailed history was obtained from each subject, and each subject received a detailed neurological examination. To confirm the CAG repeat expansion in the AR gene, genomic DNA was extracted from the peripheral blood of patients. The family consisted of 128 individuals over five generations, with two consanguineous parents, one slightly affected female, and 12 affected males with SBMA. We studied the five surviving male patients and one surviving female carrier. The age at disease onset, phenotypic features, and disease severity varied among the family members. DNA analysis was performed on five individuals, belonging to five generations of the family. Four affected males and a slightly affected female carrier were shown to carry an expanded CAG repeat in the androgen receptor gene. This family report is consistent with previous studies suggesting that SBMA may be present with a wide clinical spectrum in affected family members. Further descriptions of SBMA affected families with different ethnic backgrounds may assist in identifying possible phenotypic and genetic features of the disease. PMID:20184516

Karaer, Hatice; Kaplan, Yüksel; Kurt, Semiha; Gundogdu, Asli; Erdo?an, Begüm; Ba?ak, Nazli A

2010-01-01

375

Major histocompatibility genes in the Lake Tana African large barb species flock: evidence for complete partitioning of class II B , but not class I, genes among different species  

Microsoft Academic Search

The 16 African ‘large’ barb fish species of Lake Tana inhabit different ecological niches, exploit different food webs and have different temporal and spatial spawning patterns within the lake. This unique fish species flock is thought to be the result of adaptive radiation within the past 5 million years. Previous analyses of major histocompatibility class II B exon 2 sequences

Corine P. Kruiswijk; Trudi Hermsen; Joost van Heerwaarden; Brian Dixon; Huub F. J. Savelkoul; René J. M. Stet

2005-01-01

376

A 28,000 Years Old Cro-Magnon mtDNA Sequence Differs from All Potentially Contaminating Modern Sequences  

PubMed Central

Background DNA sequences from ancient speciments may in fact result from undetected contamination of the ancient specimens by modern DNA, and the problem is particularly challenging in studies of human fossils. Doubts on the authenticity of the available sequences have so far hampered genetic comparisons between anatomically archaic (Neandertal) and early modern (Cro-Magnoid) Europeans. Methodology/Principal Findings We typed the mitochondrial DNA (mtDNA) hypervariable region I in a 28,000 years old Cro-Magnoid individual from the Paglicci cave, in Italy (Paglicci 23) and in all the people who had contact with the sample since its discovery in 2003. The Paglicci 23 sequence, determined through the analysis of 152 clones, is the Cambridge reference sequence, and cannot possibly reflect contamination because it differs from all potentially contaminating modern sequences. Conclusions/Significance: The Paglicci 23 individual carried a mtDNA sequence that is still common in Europe, and which radically differs from those of the almost contemporary Neandertals, demonstrating a genealogical continuity across 28,000 years, from Cro-Magnoid to modern Europeans. Because all potential sources of modern DNA contamination are known, the Paglicci 23 sample will offer a unique opportunity to get insight for the first time into the nuclear genes of early modern Europeans. PMID:18628960

Caramelli, David; Milani, Lucio; Vai, Stefania; Modi, Alessandra; Pecchioli, Elena; Girardi, Matteo; Pilli, Elena; Lari, Martina; Lippi, Barbara; Ronchitelli, Annamaria; Mallegni, Francesco; Casoli, Antonella; Bertorelle, Giorgio; Barbujani, Guido

2008-01-01

377

Potential nitrogen fixation activity of different aged biological soil crusts from rehabilitated grasslands of the hilly Loess Plateau, China  

USGS Publications Warehouse

Biological soil crusts (biocrusts) cover up to 60–70% of the soil surface in grasslands rehabilitated during the "Grain for Green" project implemented in the hilly Loess Plateau region in 1999. As biocrusts fix nitrogen (N), they are an important part of restoring soil fertility. We measured nitrogenase activity (NA) in biocrusts from sites rehabilitated at six different time periods to estimate 1) the effects of moisture content and temperature on NA in biocrusts of different ages and 2) the potential N contribution from biocrusts to soils and plants in this region. Results show that NA in the biocrusts was mostly controlled by the species composition, as the activity of biocrusts dominated by free-living soil cyanobacteria was significantly higher than that of moss-dominated biocrusts. Nitrogenase activity was also influenced by soil moisture content and ambient temperature, with a significant decline in activity when moisture levels were decreased to 20% field water-holding capacity. The optimal temperature for NA was 35–40 °C and 30–40 °C for cyanobacteria- and moss-dominated biocrusts, respectively. Biocrust fixed N is likely an important source of N in this ecosystem, as we estimated annual potential N inputs per hectare in these grasslands to be up to 13 kg N ha-1 and 4 kg N ha-1 for cyanobacteria- and moss-dominated biocrusts, respectively.

Zhao, Y.; Xu, M.; Belnap, J.

2010-01-01

378

Potential enhanced ability of giant squid to detect sperm whales is an exaptation tied to their large body size  

PubMed Central

It has been hypothesized that sperm whale predation is the driver of eye size evolution in giant squid. Given that the eyes of giant squid have the size expected for a squid this big, it is likely that any enhanced ability of giant squid to detect whales is an exaptation tied to their body size. Future studies should target the mechanism behind the evolution of large body size, not eye size. Reconstructions of the evolutionary history of selective regime, eye size, optical performance, and body size will improve the understanding of the evolution of large eyes in large ocean animals. PMID:24127991

2013-01-01

379

Potential enhanced ability of giant squid to detect sperm whales is an exaptation tied to their large body size.  

PubMed

It has been hypothesized that sperm whale predation is the driver of eye size evolution in giant squid. Given that the eyes of giant squid have the size expected for a squid this big, it is likely that any enhanced ability of giant squid to detect whales is an exaptation tied to their body size. Future studies should target the mechanism behind the evolution of large body size, not eye size. Reconstructions of the evolutionary history of selective regime, eye size, optical performance, and body size will improve the understanding of the evolution of large eyes in large ocean animals. PMID:24127991

Schmitz, Lars; Motani, Ryosuke; Oufiero, Christopher E; Martin, Christopher H; McGee, Matthew D; Wainwright, Peter C

2013-01-01

380

[Changes in components of the auditory long-latency evoked potentials at different stages of the slow-wave sleep].  

PubMed

In accordance with the present views, during sleep, analysis of external stimuli continues at the subconscious level, because the need to estimate the biological significance of external stimuli in order to maintain a flexible contact of a sleeping subject with the environment persists during sleep. It is known that new components of the auditory evoked potentials (AEP) appear as sleep deepens. However, the common procedure of analysis of event-related potentials averaged for a group of subjects has some drawbacks because of the interindividual variability of the event-related potentials. Therefore, an additional analysis of the interindividual variability of the AEP shape and component structure can simplify the detection of individual components of group-averaged AEP at different stages of the slow-wave sleep. The AEPs were recorded in healthy volunteers (n = 26) during falling asleep in the evening from eight EEG derivations (F3, F4, C3, C4, P3, P4, O1, O2) in reference to a linked mastoid electrode. Computer-generated sound stimuli (50 ms-pulses with the frequency of 1000 Hz, 60 dB HL) were presented binaurally through earphones with interstimulus intervals of 20-40 s. Selective summation of AEPs for all the subjects was performed for each stage of the slow-wave sleep individually for each of the eight derivations. It was shown that the account made for interindividual variability of the AEP shape facilitated the identification of individual components of the group-averaged AEP typical of wakefulness (P1, N1, P300) and those which appeared during sleep onset and at different stages of the slow-wave sleep (P2, N350, P450, N550, N900). PMID:15828419

Dorokhov, V B; Verbitskaia, Iu S

2005-01-01

381

Sex differences and effects of neonatal aromatase inhibition on masculine and feminine copulatory potentials in prairie voles.  

PubMed

Copulatory behaviors in most rodents are highly sexually dimorphic, even when circulating hormones are equated between the sexes. Prairie voles (Microtus ochrogaster) are monomorphic in their display of some social behaviors, including partner preferences and parenting, but differences between the sexes in their masculine and feminine copulatory behavior potentials have not been studied in detail. Furthermore, the role of neonatal aromatization of testosterone to estradiol on the development of prairie vole sexual behavior potentials or their brain is unknown. To address these issues, prairie vole pups were injected daily for the first week after birth with 0.5 mg of the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD) or oil. Masculine and feminine copulatory behaviors in response to testosterone or estradiol were later examined in both sexes. Males and females showed high mounting and thrusting in response to testosterone, but only males reliably showed ejaculatory behavior. Conversely, males never showed feminine copulatory behaviors in response to estradiol. Sex differences in these behaviors were not affected by neonatal ATD, but ATD-treated females received fewer mounts and thrusts than controls, possibly indicating reduced attractiveness to males. In other groups of subjects, neonatal ATD demasculinized males' tyrosine hydroxylase expression in the anteroventral periventricular preoptic area, and estrogen receptor alpha expression in the medial preoptic area. Thus, although sexual behavior in both sexes of prairie voles is highly masculinized, aromatase during neonatal life is necessary only for females' femininity. Furthermore, copulatory behavior potentials and at least some aspects of brain development in male prairie voles are dissociable by their requirement for neonatal aromatase. PMID:18378236

Northcutt, Katharine V; Lonstein, Joseph S

2008-06-01

382

The Potential for Measuring Slow Crustal Evolution using Ar-Ar Dating of Large K-feldspar Crystals  

NASA Astrophysics Data System (ADS)

There has been a great deal of debate concerning Ar/Ar age profiles in K-feldspar, even gem quality K-feldspar which should exhibit simple diffusion behaviour. Here we explore their potential for measuring very slow crustal evolution and cratonization. Several different models have been evoked which if correct would challenge our capability to recover long thermal histories from Ar/Ar data. We have measured 40Ar/39Ar ages in gem quality K-feldspar grains from Itrongay Madagascar of 435 [1] - 477 [2] Ma using UV-laserprobe to produce both depth profiles (0-20 microns) and spot traverses (0-1000 microns) to test the mechanisms that might control Ar diffusion in nature. Micron scale UV laser depth profiling was used to determine Ar diffusion adjacent to the natural crystal surface (presumed to have formed as the sample crystallised). UV laser spot dating was used to measure the age variations on length scales of 10s of microns to mm and even cm. The high potassium content and age of the Itrongay sample made it possible to measure natural argon age profiles at high precision and high spatial resolution, to address some of the issues surrounding Ar diffusion. The analysis reveals the presence of very long age gradients in the Itrongay feldspar spanning more than 50Ma - ages as low as 415.7±3.0 Ma were measured at the grain margin and as high as 473.8±2.2 Ma in the core. As previous work on Itrongay feldspar has tended to be carried out on mm-sized fragments without knowledge of the original crystal boundaries, the variation in radiometric ages in the published literature is likely due to these internal age variations. We interpret the age profiles as the combination of diffusion and 40K decay to 40Ar over the full range of spatial scales from micron to centimetre. Thermal models for the thermal history of Itrongay K-feldspar appear to be in agreement with previous thermochronology in the area and hold out the hope for unravelling very long and slow crustal evolution based on the deep crust which might be tied into slowly evolving landforms on the surface. 1. Arnaud, N. O., and S. P. Kelley. 1997. "Argon behaviour in gem-quality orthoclase from Madagascar: Experiments and some consequences for 40Ar/39Ar geochronology." Geochimica et Cosmochimica Acta. 61, 3227-3255. 2. Nägler, Th. F., and I. M. Villa. 2000. "In pursuit of the 40K branching ratios: K-Ca and 39Ar-40Ar dating of gem silicates." Chemical Geology. 169 , 5-16.

Kelley, S. P.; Flude, S.

2012-12-01

383

A Different View on the Checkerboard? Alterations in Early and Late Visually Evoked EEG Potentials in Asperger Observers  

PubMed Central

Background Asperger Autism is a lifelong psychiatric condition with highly circumscribed interests and routines, problems in social cognition, verbal and nonverbal communication, and also perceptual abnormalities with sensory hypersensitivity. To objectify both lower-level visual and cognitive alterations we looked for differences in visual event-related potentials (EEG) between Asperger observers and matched controls while they observed simple checkerboard stimuli. Methods In a balanced oddball paradigm checkerboards of two checksizes (0.6° and 1.2°) were presented with different frequencies. Participants counted the occurrence times of the rare fine or rare coarse checkerboards in different experimental conditions. We focused on early visual ERP differences as a function of checkerboard size and the classical P3b ERP component as an indicator of cognitive processing. Results We found an early (100–200 ms after stimulus onset) occipital ERP effect of checkerboard size (dominant spatial frequency). This effect was weaker in the Asperger than in the control observers. Further a typical parietal/central oddball-P3b occurred at 500 ms with the rare checkerboards. The P3b showed a right-hemispheric lateralization, which was more prominent in Asperger than in control observers. Discussion The difference in the early occipital ERP effect between the two groups may be a physiological marker of differences in the processing of small visual details in Asperger observers compared to normal controls. The stronger lateralization of the P3b in Asperger observers may indicate a stronger involvement of the right-hemispheric network of bottom-up attention. The lateralization of the P3b signal might be a compensatory consequence of the compromised early checksize effect. Higher-level analytical information processing units may need to compensate for difficulties in low-level signal analysis. PMID:24632708

Kornmeier, Juergen; Wörner, Rike; Riedel, Andreas; Bach, Michael; Tebartz van Elst, Ludger

2014-01-01

384

Selection for Unequal Densities of Sigma70 Promoter-like Signalsin Different Regions of Large Bacterial Genomes  

SciTech Connect

The evolutionary processes operating in the DNA regions that participate in the regulation of gene expression are poorly understood. In Escherichia coli, we have established a sequence pattern that distinguishes regulatory from nonregulatory regions. The density of promoter-like sequences, that are recognizable by RNA polymerase and may function as potential promoters, is high within regulatory regions, in contrast to coding regions and regions located between convergently-transcribed genes. Moreover, functional promoter sites identified experimentally are often found in the subregions of highest density of promoter-like signals, even when individual sites with higher binding affinity for RNA polymerase exist elsewhere within the regulatory region. In order to investigate the generality of this pattern, we have used position weight matrices describing the -35 and -10 promoter boxes of E. coli to search for these motifs in 43 additional genomes belonging to most established bacterial phyla, after specific calibration of the matrices according to the base composition of the noncoding regions of each genome. We have found that all bacterial species analyzed contain similar promoter-like motifs, and that, in most cases, these motifs follow the same genomic distribution observed in E. coli. Differential densities between regulatory and nonregulatory regions are detectable in most bacterial genomes, with the exception of those that have experienced evolutionary extreme genome reduction. Thus, the phylogenetic distribution of this pattern mirrors that of genes and other genomic features that require weak selection to be effective in order to persist. On this basis, we suggest that the loss of differential densities in the reduced genomes of host-restricted pathogens and symbionts is the outcome of a process of genome degradation resulting from the decreased efficiency of purifying selection in highly structured small populations. This implies that the differential distribution of promoter-like signals between regulatory and nonregulatory regions detected in large bacterial genomes confers a significant, although small, fitness advantage. This study paves the way for further identification of the specific types of selective constraints that affect the organization of regulatory regions and the overall distribution of promoter-like signals through more detailed comparative analyses among closely-related bacterial genomes.

Huerta, Araceli M.; Francino, M. Pilar; Morett, Enrique; Collado-Vides, Julio

2006-03-01

385

Distinct disease phenotypes linked to different combinations of GAA mutations in a large late-onset GSDII sibship  

PubMed Central

Background Glycogenosis type II (GSDII or Pompe disease) is an autosomal recessive disease, often characterized by a progressive accumulation of glycogen within lysosomes caused by a deficiency of ?-1,4-glucosidase (GAA; acid maltase), a key enzyme of the glycogen degradation pathway. To date, more than 326 different mutations in the GAA gene have been identified in patients with GSDII but the course of the disease is difficult to be predicted on the basis of molecular genetic changes. Studies on large informative families are advisable to better define how genetics and non genetics factors like exercise and diet may influence the clinical phenotype. Methods and results In this study, we report on clinical, instrumental, and pathological features as well as on molecular analysis of a family with 10 out of 13 siblings affected by late-onset Pompe disease. Three mutations segregated in the family, two of which are novel mutations. Siblings showing a more severe phenotype were compound heterozygous for c.118C?>?T [p.R40X] and c.2647-7G?>?A [p.N882fs] on GAA, whereas, two patients showing a mild phenotype were compound heterozygous c.2647-7G?>?A [p.N882fs] and c.2276G?>?C [p.G759A] mutations. Quantitative expression analysis showed, in the patients carrying p.R40X/ p.N882fs, a significant (p 0.01) correlation between the levels of expression of the mutated allele and the age at onset of the disease. Conclusions As far as we know, this is the largest informative family with late-onset Pompe disease described in the literature showing a peculiar complex set of mutations of GAA gene that may partially elucidate the clinical heterogeneity of this family. PMID:24107549

2013-01-01

386

Differences in visuo-motor control in skilled vs. novice martial arts athletes during sustained and transient attention tasks: a motor-related cortical potential study.  

PubMed

Cognitive and motor processes are essential for optimal athletic performance. Individuals trained in different skills and sports may have specialized cognitive abilities and motor strategies related to the characteristics of the activity and the effects of training and expertise. Most studies have investigated differences in motor-related cortical potential (MRCP) during self-paced tasks in athletes but not in stimulus-related tasks. The aim of the present study was to identify the differences in performance and MRCP between skilled and novice martial arts athletes during two different types of tasks: a sustained attention task and a transient attention task. Behavioral and electrophysiological data from twenty-two martial arts athletes were obtained while they performed a continuous performance task (CPT) to measure sustained attention and a cued continuous performance task (c-CPT) to measure transient attention. MRCP components were analyzed and compared between groups. Electrophysiological data in the CPT task indicated larger prefrontal positive activity and greater posterior negativity distribution prior to a motor response in the skilled athletes, while novices showed a significantly larger response-related P3 after a motor response in centro-parietal areas. A different effect occurred in the c-CPT task in which the novice athletes showed strong prefrontal positive activity before a motor response and a large response-related P3, while in skilled athletes, the prefrontal activity was absent. We propose that during the CPT, skilled athletes were able to allocate two different but related processes simultaneously according to CPT demand, which requires controlled attention and controlled motor responses. On the other hand, in the c-CPT, skilled athletes showed better cue facilitation, which permitted a major economy of resources and "automatic" or less controlled responses to relevant stimuli. In conclusion, the present data suggest that motor expertise enhances neural flexibility and allows better adaptation of cognitive control to the requested task. PMID:24621480

Sanchez-Lopez, Javier; Fernandez, Thalia; Silva-Pereyra, Juan; Martinez Mesa, Juan A; Di Russo, Francesco

2014-01-01

387

Differences in Visuo-Motor Control in Skilled vs. Novice Martial Arts Athletes during Sustained and Transient Attention Tasks: A Motor-Related Cortical Potential Study  

PubMed Central

Cognitive and motor processes are essential for optimal athletic performance. Individuals trained in different skills and sports may have specialized cognitive abilities and motor strategies related to the characteristics of the activity and the effects of training and expertise. Most studies have investigated differences in motor-related cortical potential (MRCP) during self-paced tasks in athletes but not in stimulus-related tasks. The aim of the present study was to identify the differences in performance and MRCP between skilled and novice martial arts athletes during two different types of tasks: a sustained attention task and a transient attention task. Behavioral and electrophysiological data from twenty-two martial arts athletes were obtained while they performed a continuous performance task (CPT) to measure sustained attention and a cued continuous performance task (c-CPT) to measure transient attention. MRCP components were analyzed and compared between groups. Electrophysiological data in the CPT task indicated larger prefrontal positive activity and greater posterior negativity distribution prior to a motor response in the skilled athletes, while novices showed a significantly larger response-related P3 after a motor response in centro-parietal areas. A different effect occurred in the c-CPT task in which the novice athletes showed strong prefrontal positive activity before a motor response and a large response-related P3, while in skilled athletes, the prefrontal activity was absent. We propose that during the CPT, skilled athletes were able to allocate two different but related processes simultaneously according to CPT demand, which requires controlled attention and controlled motor responses. On the other hand, in the c-CPT, skilled athletes showed better cue facilitation, which permitted a major economy of resources and “automatic” or less controlled responses to relevant stimuli. In conclusion, the present data suggest that motor expertise enhances neural flexibility and allows better adaptation of cognitive control to the requested task. PMID:24621480

Sanchez-Lopez, Javier; Fernandez, Thalia; Silva-Pereyra, Juan; Martinez Mesa, Juan A.; Di Russo, Francesco

2014-01-01

388

Drought in the U.S. Great Plains (1980-2012): A sensitivity study using different methods for estimating potential evapotranspiration in the Palmer Drought Severity Index  

NASA Astrophysics Data System (ADS)

Palmer Drought Severity Index (PDSI) has been widely used to evaluate drought conditions since it was developed in 1965. In the original formulation of the PDSI, potential evapotranspiration (PET) was estimated using the Thornthwaite equation. This study evaluates how using more physically based approaches for estimating PET influences the depiction of drought conditions over the U.S. Great Plains from 1980 to 2012. Both the Penman-Monteith equation and the two-source PET model are compared to the original Thornthwaite-based PDSI. The differences in PET between the three methods are much larger than the resulting differences in the PDSI. Results show that the original PDSI has a stronger drying trend than versions of PDSI that use more physically based methods of estimating PET. Spatially, all three versions of the PDSI show similar distributions of drying and wetting trends; however, there are significant regional variations that appear to be associated with land cover. PDSI and observed soil moisture in the top 1 m are moderately correlated (correlation coefficient is ~0.5) over the U.S. Great Plains, except in Texas (correlation coefficient is ~0.3). Although all three approaches result in a similar area-averaged PDSI for the U.S. Great Plains, there are large differences in the area affected by drought, especially during extreme drought events.

Yuan, Shanshui; Quiring, Steven M.

2014-10-01

389

The potential of selected macroalgal species for treatment of AMD at different pH ranges in temperate regions.  

PubMed

The metal bioaccumulation potential of selected macroalgae species at different pH ranges was study for usage as part of a possible secondary passive acid mine drainage (AMD) treatment technology in algae ponds. Two separate studies were conducted to determine the suitability of macroalgae for passive treatment when metabolic processes in macrophytes and microorganisms in constructed wetlands decrease during winter months. In the field study, the bioconcentration of metals (mg/kg dry weight) measured in the benthic macroalgae mats was in the following order: site 1. Oedogonium crassum Al > Fe > Mn > Zn; site 2. Klebsormidium klebsii, Al > Fe > Mn > Zn; site 3. Microspora tumidula, Fe > Al > Mn > Zn and site 4. M. tumidula, Fe > Mn > Al > Zn. In the laboratory study, cultured macroalgae K. klebsii, O. crassum and M. tumidula isolated from the field sampling sites were exposed to three different pH values (3, 5 and 7), while bioaccumulation of the metals, Al, Fe, Mn and Zn and glutathione S-transferase (GST) activity were measured in the different selected algae species at a constant water temperature of 14 °C. Bioaccumulation of Al was the highest for O. crassum followed by K. klebsii and M. tumidula (p < 0.0001). From the study it was evident that the highest metal bioaccumulation occurred in the macroalgae O. crassum at all three tested pH values under constant low water temperature. PMID:24835955

Oberholster, Paul J; Cheng, Po-Hsun; Botha, Anna-Maria; Genthe, Bettina

2014-09-01

390

Geographic variations of life history traits and potential trade-offs in different populations of the parasitoid Leptopilina heterotoma  

NASA Astrophysics Data System (ADS)

Energy allocation is determined by resource availability and trade-offs among traits, and so organisms have to give some traits priority over others to maximize their fitness according to their environment. In this study, we investigated the geographic variations in life history traits and potential trade-offs in populations of the parasitoid Leptopilina heterotoma (Hymenoptera: Figitidae) originating from the north and the south of the Rhône-Saône valley (over a gradient of 300 km, South-East France). We measured a set of traits related to reproduction, maintenance, and mobility using several estimators of each of these main functions determined at different times. We did not find any clear differences between populations from contrasting areas, whereas the southern populations, which were all assumed to be exposed to similar environmental conditions, displayed contrasting patterns of energy allocation. Thus, the most likely explanation seems to be that the evolution of the life history of L. heterotoma is probably shaped by local selective pressures, such as microclimate, microhabitats, or intensity of competition, rather than by regional ecological conditions. Using our study as an example, we discuss the interest of considering several traits and using different ways of measuring them, concluding that multiple measurements should be performed in future studies to ensure the robustness of the results.

Vuarin, Pauline; Allemand, Roland; Moiroux, Joffrey; van Baaren, Joan; Gibert, Patricia

2012-11-01

391

Assay of Antioxidant Potential of Two Aspergillus Isolates By Different Methods Under Various Physio-Chemical Conditions  

PubMed Central

The objective of this work was to screen fungi isolated from soil of different areas of Punjab, India for antioxidant activity by dot blot assay and around 45% of fungal isolates demonstrated antioxidant potential. Two selected strains of Aspergillus spp (Aspergillus PR78 and Aspergillus PR66) showing quantitatively best antioxidant activity by DPPH assay were further tested for their reducing power, ferrous ion and nitric oxide ion scavenging activity, FRAP assay and total phenolic content. Different physio-chemical parameters were optimized for enhancement of the activity. This revealed stationary culture grown for 10 days at 25 oC at pH 7 to be the best for antioxidant activity. Sucrose in the medium as carbon source resulted in highest antioxidant activity. Sodium nitrate, yeast extract, and peptone were good sources of nitrogen but sodium nitrate was the best among these. The extraction of the broth culture filtrates with different solvents revealed ethyl acetate extract to possess the best antioxidant activity. The activity as expressed by ethyl acetate extract of Aspergillus PR78 was equally effective as that of commonly used antioxidant standard, ascorbic acid. PMID:24031554

Arora, Daljit Singh; Chandra, Priyanka

2010-01-01

392

Potential of the Large Observatory for X-ray Timing telescope for the search for dark matter  

NASA Astrophysics Data System (ADS)

Large observatory for x-ray timing (LOFT) is a concept of a next-generation x-ray telescope considered in the context of the "Cosmic Vision" program of the European Space Agency. The Large Area Detector on board of LOFT will be a collimator-type telescope with an unprecedentedly large collecting area of about 1 05 cm2 in the energy band between 2 and 100 keV. We demonstrate that LOFT will be a powerful dark matter detector, suitable for the search of the x-ray line emission expected from decays of light dark matter particles in galactic halos. We show that LOFT will have sensitivity for dark matter line search more than an order of magnitude higher than that of all existing x-ray telescopes. In this way, LOFT will be able to provide a new insight into the fundamental problem of the nature of dark matter.

Neronov, A.; Boyarsky, A.; Iakubovskyi, D.; Ruchayskiy, O.

2014-12-01

393

The large-leaved Kudingcha (Ilex latifolia Thunb and Ilex kudingcha C.J. Tseng): a traditional Chinese tea with plentiful secondary metabolites and potential biological activities.  

PubMed

In China, Kudingcha has been used for almost 2,000 years as a tea to quench thirst, remove phlegm, refresh the mind, and improve eyesight. The group of large-leaved Kudingcha is coveted for its potential effects on lipid metabolism, which are attributed to the presence of characteristic ingredients. This contribution reviews studies from the past few decades regarding the plant characteristics, ethnobotanical usages, chemical constituents, and related biological activities of the large-leaved Kudingcha (Ilex latifolia Thunb and Ilex kudingcha C.J. Tseng). Triterpenoids, phenolic acids, flavonoids, and essential oils are the main metabolites in the large-leaved Kudingcha, and these ingredients protect the vascular system, regulate lipid metabolism, and have antioxidant, hypoglycemic, and anti-tumo