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1

International Nuclear Information System (INIS)

Measurement of activation reaction rates was carried out for fast neutrons penetrating through graphite and water from the core of JRR-4 research reactor of JAERI, with paying attention to the energy above 10 MeV. Analysis of the experiment was made using a vectorized continuous energy Monte Carlo code MVP to verify the code. The analysis shows good agreements between the measurement and calculation and the MVP code has been confirmed its validity for the fast neutron transport calculations above 10 MeV in fission neutron field. (author)

2

Calculation using MVP and MVP-BURN in JRR-3

International Nuclear Information System (INIS)

MVP is the particle-transport Monte Carlo code that has been developed in JAEA. MVP-BURN is an added function to do burn-up calculation. It is easy to built complex structure like core for MVP. And it is easy to do calculations of keff, any reaction rate, flux, burn-up and so on. In this report, it is introduced MVP and MVP-BURN. And some sample calculations of JRR-3 are shown. (author)

3

Development of fast and accurate Monte Carlo code MVP

International Nuclear Information System (INIS)

The development work of fast and accurate Monte Carlo code MVP has started at JAERI in late 80s. From the beginning, the code was designed to utilize vector supercomputers and achieved higher computation speed by a factor of 10 or more compared with conventional codes. In 1994, the first version of MVP was released together with cross section libraries based on JENDL-3.1 and JENDL-3.2. In 1996, minor revision was made by adding several functions such as treatments of ENDF-B6 file 6 data, time dependent problem, and so on. Since 1996, several works have been carried out for the next version of MVP. The main works are (1) the development of continuous energy Monte Carlo burn-up calculation code MVP-BURN, (2) the development of a system to generate cross section libraries at arbitrary temperature, and (3) the study on error estimations and their biases in Monte Carlo eigenvalue calculations. This paper summarizes the main features of MVP, results of recent studies and future plans for MVP. (author)

4

Atomic Zitterbewegung in Abelian vector gauge potentials

International Nuclear Information System (INIS)

We propose a scheme to realize Zitterbewegung (ZB) with cold atoms in an Abelian vector potential. Two dark states can be created by interacting alkali-metal atoms with three coaxial Gaussian beams. Atoms moving in the subspace spanned by the two dark states feel a vector gauge potential that is nonvanishing only along the laser axis. We show that cold atoms in this Abelian vector potential undergo ZB with a large amplitude detectable in experiment.

5

An introduction to the vector potential

International Nuclear Information System (INIS)

We present a review and discussion of the physical meaning of the vector potential in electromagnetism by means of a classical experiment in which a long solenoid, connected to a sinusoidal voltage supply, produces an electric field and a vector potential in a circuit exterior to the solenoid itself. Some basic considerations are recalled concerning the meaning of action-at-a-distance and local description, in terms of 'real fields' of the induced electromotive force on the circuit outside the solenoid. From this viewpoint the roles played by the magnetic field, the electric field and the vector potential to account for the physical effects are reviewed. Finally, the connections between these considerations and the magnetic Aharonov-Bohm effect are recalled in the light of recent theoretical work aimed at explaining the Aharonov-Bohm phase shift in terms of the magnetic field without resorting to the vector potential

6

International Nuclear Information System (INIS)

The Monte Carlo MVP code system was adopted for the Reaktor TRIGA PUSAPTI (RTP) core calculation. MVP was developed by a group of researcher of Japan Atomic Energy Agency (JAEA) first in 1994. MVP is a general multi-purpose Monte Carlo code for neutron and photon transport calculation and able to estimate an accurate simulation problems. The MVP Monte Carlo code calculation is based on the continuous energy method. This code is capable of adopting an accurate physics model, geometry description and variance reduction technique faster than conventional method. With compared to the conventional scalar method, this code could achieve higher computational speed by several factor on the vector super-computer. In this calculation, RTP core was modeled as close as possible to the real core and results of keff, flux, fission densities and others obtained from MVP were outputted. (author)

7

Energy Technology Data Exchange (ETDEWEB)

At Center for Promotion of Computational Science and Engineering, time consuming eight nuclear codes suggested by users have been vectorized, parallelized on the VPP500 computer system. In addition, two nuclear codes used on the VP2600 computer system were implemented on the VPP500 computer system. Neutron and photon transport calculation code MVP/GMVP and relativistic quantum molecular dynamics code QMDRELP have been parallelized. Extended quantum molecular dynamics code EQMD and adiabatic base calculation code HSABC have been parallelized and vectorized. Ballooning turbulence simulation code CURBAL, 3-D non-stationary compressible fluid dynamics code STREAM V3.1, operating plasma analysis code TOSCA and eddy current analysis code EDDYCAL have been vectorized. Reactor safety analysis code RELAP5/MOD2/C36-05 and RELAP5/MOD3 were implemented on the VPP500 computer system. (author)

Nemoto, Toshiyuki; Watanabe, Hideo; Fujita, Toyozo [Fujitsu Ltd., Tokyo (Japan); Kawai, Wataru; Harada, Hiroo; Gorai, Kazuo; Yamasaki, Kazuhiko; Shoji, Makoto; Fujii, Minoru

1996-06-01

8

International Nuclear Information System (INIS)

At Center for Promotion of Computational Science and Engineering, time consuming eight nuclear codes suggested by users have been vectorized, parallelized on the VPP500 computer system. In addition, two nuclear codes used on the VP2600 computer system were implemented on the VPP500 computer system. Neutron and photon transport calculation code MVP/GMVP and relativistic quantum molecular dynamics code QMDRELP have been parallelized. Extended quantum molecular dynamics code EQMD and adiabatic base calculation code HSABC have been parallelized and vectorized. Ballooning turbulence simulation code CURBAL, 3-D non-stationary compressible fluid dynamics code STREAM V3.1, operating plasma analysis code TOSCA and eddy current analysis code EDDYCAL have been vectorized. Reactor safety analysis code RELAP5/MOD2/C36-05 and RELAP5/MOD3 were implemented on the VPP500 computer system. (author)

9

Parallelization of Monte Carlo codes MVP/GMVP

Energy Technology Data Exchange (ETDEWEB)

General-purpose Monte Carlo codes MVP/GMVP are well-vectorized and thus enable us to perform high-speed Monte Carlo calculations. In order to achieve more speedups, we parallelized the codes on the different types of the parallel processing platforms. The platforms reported are a distributed-memory vector-parallel computer Fujitsu VPP500, a distributed-memory massively parallel computer Intel Paragon and a distributed-memory scalar-parallel computer Hitachi SR2201. As mentioned generally, ideal speedup could be obtained for large-scale problems but parallelization efficiency got worse as the batch size per a processing element (PE) was smaller. (author)

Nagaya, Yasunobu; Mori, Takamasa; Nakagawa, Masayuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Sasaki, Makoto

1998-03-01

10

Parallelization of Monte Carlo codes MVP/GMVP

International Nuclear Information System (INIS)

General-purpose Monte Carlo codes MVP/GMVP are well-vectorized and thus enable us to perform high-speed Monte Carlo calculations. In order to achieve more speedups, we parallelized the codes on the different types of the parallel processing platforms. The platforms reported are a distributed-memory vector-parallel computer Fujitsu VPP500, a distributed-memory massively parallel computer Intel Paragon and a distributed-memory scalar-parallel computer Hitachi SR2201. As mentioned generally, ideal speedup could be obtained for large-scale problems but parallelization efficiency got worse as the batch size per a processing element (PE) was smaller. (author)

11

Relativistic scattering theory with a vector potential

International Nuclear Information System (INIS)

The aim of this project, as the title indicates, was to investigate relativistic scattering theory when there is a vector as well as a scalar potential, in order to improve upon earlier theories which include magnetic effects via an effective B-field. A single-site scattering site was described by a scalar and a vector potential. Both potentials were inside a muffin-tin sphere, outside of which they are zero. The Kohn-Sham-Dirac equations were solved inside and outside the muffin tin sphere and the solutions were matched at the boundary in order to calculate the single-site scattering quantities. Next the multiple-site scattering path operator .for the full potential case was calculated using the KKR equation and then important observables were obtained, such as the density of states, the magnetic moment, the charge and the current densities. Although the shape of the potential is not in general spherical, the shape is still limited by the muffin tin approximation. The theory and the code were illustrated by a detailed investigation of two different non-spherical forms for the vector potential and one form for the non-spherical scalar potential. Although the code is written to describe an arbitrary sized cluster of atoms, the size of the cluster treated in this project is severely restricted by computational limitations. (author)

12

Biochemical and structural analysis of the hyperpolarization-activated K(+) channel MVP.

In contrast to the majority of voltage-gated ion channels, hyperpolarization-activated channels remain closed at depolarizing potentials and are activated at hyperpolarizing potentials. The basis for this reverse polarity is thought to be a result of differences in the way the voltage-sensing domain (VSD) couples to the pore domain. In the absence of structural data, the molecular mechanism of this reverse polarity coupling remains poorly characterized. Here we report the characterization of the structure and local dynamics of the closed activation gate (lower S6 region) of MVP, a hyperpolarization-activated potassium channel from Methanococcus jannaschii, by electron paramagnetic resonance (EPR) spectroscopy. We show that a codon-optimized version of MVP has high expression levels in Escherichia coli, is purified as a stable tetramer, and exhibits expected voltage-dependent activity when reconstituted in liposomes. EPR analysis of the mid to lower S6 region revealed positions exhibiting strong spin-spin coupling, indicating that the activation gate of MVP is closed at 0 mV. A comparison of local environmental parameters along the activation gate for MVP and KcsA indicates that MVP adopts a different closed conformation. These structural details set the stage for future evaluations of reverse electromechanical coupling in MVP. PMID:24490868

Randich, Amelia M; Cuello, Luis G; Wanderling, Sherry S; Perozo, Eduardo

2014-03-18

13

MVP utilization for PWR design code

International Nuclear Information System (INIS)

MHI studies the method of the spatially dependent resonance cross sections so as to predict the power distribution in a fuel pellet accurately. For this purpose, the multiband method and the Stoker/Weiss method were implemented to the 2 dimensional transport code PHOENIX-P, and the methods were validated by comparing them with MVP code. Although the appropriate reference was not obtain from the deterministic codes on the resonance cross section study, now the Monte Carlo code MVP result is available and useful as reference. It is shown here how MVP is used to develop the multiband method and the Stoker/Weiss method, and how effective the result of MVP is on the study of the resonance cross sections. (author)

14

Status of JAERI's Monte Carlo code MVP for neutron and photon transport problems

International Nuclear Information System (INIS)

The special features of MVP are (1) vectorization and parallelization, (2) multiple lattice capability and statistical geometry model, (3) probability table method for unresolved resonance, (4) calculation at arbitrary temperatures, (5) depletion calculation, (6) perturbation calculation for eigenvalue (keff) problem, and so on. (orig.)

15

Status of JAERI’s Monte Carlo Code MVP for Neutron and Photon Transport Problems

The special features of MVP are (1) vectorization and parallelization, (2) multiple lattice capability and statistical geometry model, (3) probability table method for unresolved resonance, (4) calculation at arbitrary temperatures, (5) depletion calculation, (6) perturbation calculation for eigenvalue (K eff) problem, and so on.

Mori, T.; Okumura, K.; Nagaya, Y.

16

Reception of longitudinal vector potential radiation with a plasma antenna

Energy Technology Data Exchange (ETDEWEB)

To help resolve the long-running debate between physicists and engineers regarding the existence of the magnetic vector potential, herewith we describe an experiment demonstrating reception of time-harmonic vector potential radiation at 1.3 GHz.

Zimmerman, Robert K. Jr. [Sigma Space Corporation, NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771 (United States)

2013-07-28

17

Vector potential, electromagnetic induction and "physical meaning"

A forgotten experiment by Andr\\'e Blondel (1914) proves, as held on the basis of theoretical arguments in a previous paper, that the time variation of the magnetic flux is not the cause of the induced $emf$: the physical agent is instead the vector potential through the term $-\\partial\\vec A/\\partial t$ (when the induced circuit is at rest). The "good electromagnetic potentials" are determined by the Lorenz condition and retarded formulas. Other pairs of potentials derived through appropriate gauge functions are only mathematical devices for calculating the fields: they are not physically related to the sources. The physical meaning of a theoretical term relies, primarily, on theoretical grounds: a theoretical term has physical meaning if it cannot be withdrawn without reducing the predictive power of a theory or, in a weaker sense, if it cannot be withdrawn without reducing the descriptive proficiency of a theory.

Giuliani, Giuseppe

2010-01-01

18

Outline of MOS-1 Verification Program (MVP)

Aspects of the MVP, a verification program for the Japanese Marine Observation Satellite (MOS-1) are discussed. The MOS-1 was designed to observe ocean, land, and atmosphere, at visible, near-infrared, thermal infrared, and microwave wavelengths. The MVP was developed to evaluate the MOS-1 and its four mission instrument: the multispectral electronic self-scanning radiometer, the visible and thermal infrared radiometer, the microwave scanning radiometer, and the data collection system transponder. Evaluations of radiometric distortion compensation, signal-to-noise ratio, geometric distortion compensation, and spatial resolution are given for the three radiometers.

Maeda, Korehiro; Wakabayaski, Hiroyuki; Tasaki, Kazuyuki; Shimada, Masanobu; Sato, Hideo

1988-06-01

19

Identifying Protein Structural Classes Using MVP Algorithm

Directory of Open Access Journals (Sweden)

Full Text Available A new method for the prediction of protein structural classes is constructed based on MVP (Maximum variance projection algorithm, which is a manifold learning-based data mining method. DC (Dipeptide Composition and PseAA (Pseudo Amino Acid are used as conditional attributes for the construction of decision system. A DR (Dimensionality Reduction algorithm, the so-called MVP is introduced to reduce the decision system, which can be used to classify new objects. Experimental results thus obtained are quite encouraging, which indicate that the above method is used effectively to deal with this complicated problem of protein structural classes.

Xiaoxia Cao

2012-08-01

20

The vector potential in a branched Riemann space

International Nuclear Information System (INIS)

An attempt is made to extend the use of the vector potential to problems involving a branched space. As an example of a problem that is suitable to be solved entirely in terms of the vector potential the problem of a ring vortex element above a half-plane is worked out. The use of the scalar potential however remains slightly simpler. Another example that is treated is the simple looking problem of a straight vortex line perpendicularly crossing the edge of a half-plane. The problem is formulated in two ways, once using the scalar potential phi the other time using the vector potential A. It turns out that it is preferable to use the scalar potential and the Green's function formulation above using the method of images for the vector potential involving the more complicated integrals of distributions of ring vortices. (Auth.)

21

Vector activity and propagule size affect dispersal potential by vertebrates

Many small organisms in various life stages can be transported in the digestive system of larger vertebrates, a process known as endozoochory. Potential dispersal distances of these “propagules” are generally calculated after monitoring retrieval in experiments with resting vector animals. We argue that vectors in natural situations will be actively moving during effective transport rather than resting. We here test for the first time how physical activity of a vector animal might affect ...

Leeuwen, C. H. A.; Tollenaar, M.; Klaassen, M. R. J.

2012-01-01

22

Vector and scalar confining potentials and the Klein paradox

International Nuclear Information System (INIS)

Confining potentials in equations involving the interaction of fermions lead to no Klein paradoxes if the strength of the vector potential is appropriately limited compared to the scalar potential. For linear potentials the Regge trajectories are asymptotically like those of the harmonic oscillator, namely, E2approx.j. .AE

23

Vector performance of a potential energy functional representation

International Nuclear Information System (INIS)

In computer codes based on classical mechanics treatments of the molecular dynamics the bottleneck to vectorization is the evaluation of the potential energy and of its derivatives. These calculations are usually confined inside ad hoc routines. Quite often these routines have a complex structure motivated by the complex form of the functional adopted for representing the molecular interaction. Typical examples of potential energy routines difficult to restructure for taking advantage of vector architectures are those concerned with interactions obtained by assembling different functional forms individually designed for describing accurately particular regions of the potential energy surface. A more favourable case are global representations of the potential energy. The authors' suggestion is to follow a multi-body expansion of the interaction. This representation of the potential energy of a triatomic system is not only quite accurate, but it is also easy to vectorize. Several ways of vectorizing related codes and their performances are discussed. Applications to chemical reactions are made

24

Design and Potential of Non-Integrating Lentiviral Vectors

Directory of Open Access Journals (Sweden)

Full Text Available Lentiviral vectors have demonstrated promising results in clinical trials that target cells of the hematopoietic system. For these applications, they are the vectors of choice since they provide stable integration into cells that will undergo extensive expansion in vivo. Unfortunately, integration can have unintended consequences including dysregulated cell growth. Therefore, lentiviral vectors that do not integrate are predicted to have a safer profile compared to integrating vectors and should be considered for applications where transient expression is required or for sustained episomal expression such as in quiescent cells. In this review, the system for generating lentiviral vectors will be described and used to illustrate how alterations in the viral integrase or vector Long Terminal Repeats have been used to generate vectors that lack the ability to integrate. In addition to their safety advantages, these non-integrating lentiviral vectors can be used when persistent expression would have adverse consequences. Vectors are currently in development for use in vaccinations, cancer therapy, site-directed gene insertions, gene disruption strategies, and cell reprogramming. Preclinical work will be described that illustrates the potential of this unique vector system in human gene therapy.

Aaron Shaw

2014-01-01

25

Unique continuation for the Schrodinger equation with gradient vector potentials

We obtain unique continuation results for Schrodinger equations with time dependent gradient vector potentials. This result with an appropriate modification also yields unique continuation properties for solutions of certain nonlinear Schrodinger equations.

Dong, Hongjie; Staubach, Wolfgang

2006-01-01

26

Conception of the scalar-vector potential in contemporary electrodynamics

The present paper is devoted to consideration and discussion of a number of contradictions that take place in fundamental electrodynamics researches. A concept of the scalar-vector potential is introduced that allows us to avoid a number of challenges taking place in treatment of forces of elecrtromagnetic interaction. It is introduced the delayed scalar-vector potential allowing one to solve radiation problems at an elementary level. It is shown that in a nonmagnetized plas...

Mende, F. F.

2005-01-01

27

Algebraic solution for the vector potential in the Dirac equation

The Dirac equation for an electron in an external electromagnetic field can be regarded as a singular set of linear equations for the vector potential. Radford's method of algebraically solving for the vector potential is reviewed, with attention to the additional constraints arising from non-maximality of the rank. The extension of the method to general spacetimes is illustrated by examples in diverse dimensions with both $c$- and $a$-number wavefunctions.

Booth, H S; Jarvis, P D

2001-01-01

28

Algebraic solution for the vector potential in the Dirac equation

International Nuclear Information System (INIS)

The Dirac equation for an electron in an external electromagnetic field can be regarded as a singular set of linear equations for the vector potential. Radford's method of algebraically solving for the vector potential is reviewed, with attention to the additional constraints arising from non-maximality of the rank. The extension of the method to general spacetimes is illustrated by examples in diverse dimensions with both c- and a-number wavefunctions. (author)

29

Core Calculation of 1 MWatt PUSPATI TRIGA Reactor (RTP) using Monte Carlo MVP Code System

International Nuclear Information System (INIS)

The Monte Carlo MVP code system was adopted for the Reaktor TRIGA PUSAPTI (RTP) core calculation. The code was developed by a group of researcher of Japan Atomic Energy Agency (JAEA) first in 1994. MVP is a general multi-purpose Monte Carlo code for neutron and photon transport calculation and able to estimate an accurate simulation problems. The code calculation is based on the continuous energy method. This code is capable of adopting an accurate physics model, geometry description and variance reduction technique faster than conventional method as compared to the conventional scalar method. This code could achieve higher computational speed by several factors on the vector super-computer. In this calculation, RTP core was modeled as close as possible to the real core and results of keff flux, fission densities and others were obtained

30

Core Calculation of 1 MWatt PUSPATI TRIGA Reactor (RTP) using Monte Carlo MVP Code System

The Monte Carlo MVP code system was adopted for the Reaktor TRIGA PUSAPTI (RTP) core calculation. The code was developed by a group of researcher of Japan Atomic Energy Agency (JAEA) first in 1994. MVP is a general multi-purpose Monte Carlo code for neutron and photon transport calculation and able to estimate an accurate simulation problems. The code calculation is based on the continuous energy method. This code is capable of adopting an accurate physics model, geometry description and variance reduction technique faster than conventional method as compared to the conventional scalar method. This code could achieve higher computational speed by several factors on the vector super-computer. In this calculation, RTP core was modeled as close as possible to the real core and results of keff flux, fission densities and others were obtained.

Karim, Julia Abdul

2008-05-01

31

Parallel computing by Monte Carlo codes MVP/GMVP

International Nuclear Information System (INIS)

General-purpose Monte Carlo codes MVP/GMVP are well-vectorized and thus enable us to perform high-speed Monte Carlo calculations. In order to achieve more speedups, we parallelized the codes on the different types of parallel computing platforms or by using a standard parallelization library MPI. The platforms used for benchmark calculations are a distributed-memory vector-parallel computer Fujitsu VPP500, a distributed-memory massively parallel computer Intel paragon and a distributed-memory scalar-parallel computer Hitachi SR2201, IBM SP2. As mentioned generally, linear speedup could be obtained for large-scale problems but parallelization efficiency decreased as the batch size per a processing element(PE) was smaller. It was also found that the statistical uncertainty for assembly powers was less than 0.1% by the PWR full-core calculation with more than 10 million histories and it took about 1.5 hours by massively parallel computing. (author)

32

An adaptive mode-driven spatiotemporal motion vector prediction for wavelet video coding

The three-dimensional subband/wavelet codecs use 5/3 filters rather than Haar filters for the motion compensation temporal filtering (MCTF) to improve the coding gain. In order to curb the increased motion vector rate, an adaptive motion mode driven spatiotemporal motion vector prediction (AMDST-MVP) scheme is proposed. First, by making use of the direction histograms of four motion vector fields resulting from the initial spatial motion vector prediction (SMVP), the motion mode of the current GOP is determined according to whether the fast or complex motion exists in the current GOP. Then the GOP-level MVP scheme is thereby determined by either the S-MVP or the AMDST-MVP, namely, AMDST-MVP is the combination of S-MVP and temporal-MVP (T-MVP). If the latter is adopted, the motion vector difference (MVD) between the neighboring MV fields and the S-MVP resulting MV of the current block is employed to decide whether or not the MV of co-located block in the previous frame is used for prediction the current block. Experimental results show that AMDST-MVP not only can improve the coding efficiency but also reduce the number of computation complexity.

Zhao, Fan; Liu, Guizhong; Qi, Yong

2010-07-01

33

Potential role of ticks as vectors of bluetongue virus

When the first outbreak of bluetongue virus serotype 8 (BTV8) was recorded in North-West Europe in August 2006 and renewed outbreaks occurred in the summer of 2007 and again in 2008, the question was raised how the virus survived the winter. Since most adult Culicoides vector midges are assumed not to survive the northern European winter, and transovarial transmission in Culicoides is not recorded, we examined the potential vector role of ixodid and argasid ticks for bluetongue...

Bouwknegt, C.; Rijn, P. A.; Schipper, J. J. M.; Holzel, D.; Boonstra, J.; Nijhof, A. M.; Rooij, E. M. A.; Jongejan, F.

2010-01-01

34

MVP and vaults: a role in the radiation response

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Vaults are evolutionary highly conserved ribonucleoproteins particles with a hollow barrel-like structure. The main component of vaults represents the 110 kDa major vault protein (MVP, whereas two minor vaults proteins comprise the 193 kDa vault poly(ADP-ribose polymerase (vPARP and the 240 kDa telomerase-associated protein-1 (TEP-1. Additionally, at least one small and untranslated RNA is found as a constitutive component. MVP seems to play an important role in the development of multidrug resistance. This particle has also been implicated in the regulation of several cellular processes including transport mechanisms, signal transmission and immune responses. Vaults are considered a prognostic marker for different cancer types. The level of MVP expression predicts the clinical outcome after chemotherapy in different tumour types. Recently, new roles have been assigned to MVP and vaults including the association with the insulin-like growth factor-1, hypoxia-inducible factor-1alpha, and the two major DNA double-strand break repair machineries: non-homologous endjoining and homologous recombination. Furthermore, MVP has been proposed as a useful prognostic factor associated with radiotherapy resistance. Here, we review these novel actions of vaults and discuss a putative role of MVP and vaults in the response to radiotherapy.

Zimmermann Martina

2011-10-01

35

Utilization of MVP for research on fast reactor

International Nuclear Information System (INIS)

Utilization of the continuous energy Monte-Carlo code, MVP, for research on fast reactor in Power Reactor and Nuclear Fuel Development Corporation(PNC) is described. In this report, three types of utilization are reviewed; (1) a comparison of the eigenvalues calculated by MVP with the results by the deterministic methods, (2) an improvement of U-238 reaction rate evaluation in JUPITER experimental Analysis and (3) an evaluation of heterogeneity effects for Am reaction rates of the moderated subassemblies. Since the results of MVP can be used as references, MVP is very useful code in research on fast reactor. It is one of indispensable tools in order to verify the models in the deterministic methods. Furthermore, it can be used so as to investigate the new concept reactors, such as a reactor aiming to transmute minor actinides(MA). On the other hand, a problem of the variance reduction remains. Especially, a small reactivity cannot be estimated by MVP because of large variances. The development of a Monte-Carlo method for a small reactivity calculation will promote the utilization of MVP for research on fast reactor. (author)

36

Utilization of MVP for research on fast reactor

Energy Technology Data Exchange (ETDEWEB)

Utilization of the continuous energy Monte-Carlo code, MVP, for research on fast reactor in Power Reactor and Nuclear Fuel Development Corporation(PNC) is described. In this report, three types of utilization are reviewed; (1) a comparison of the eigenvalues calculated by MVP with the results by the deterministic methods, (2) an improvement of U-238 reaction rate evaluation in JUPITER experimental Analysis and (3) an evaluation of heterogeneity effects for Am reaction rates of the moderated subassemblies. Since the results of MVP can be used as references, MVP is very useful code in research on fast reactor. It is one of indispensable tools in order to verify the models in the deterministic methods. Furthermore, it can be used so as to investigate the new concept reactors, such as a reactor aiming to transmute minor actinides(MA). On the other hand, a problem of the variance reduction remains. Especially, a small reactivity cannot be estimated by MVP because of large variances. The development of a Monte-Carlo method for a small reactivity calculation will promote the utilization of MVP for research on fast reactor. (author)

Yokoyama, Kenji [Power Reactor and Nuclear Fuel Development Corp., Tokyo (Japan)

2001-01-01

37

The Physical Entity of Vector Potential in Electromagnetism

Directory of Open Access Journals (Sweden)

Full Text Available The scalar and vector potentials were introduced into electromagnetic physics in the second half of the nineteenth century. The chief aim was to use them as auxiliary mathematical quantities in order to solve certain practical problems.Nevertheless the discovery of the Aharonov-Bohm effect (1959 in quantum mechanics has suggested that vector potential rather than magnetic field is the causal agent in such an effect. Recent research on the Maxwell-Lodge paradox--induction of voltage in the loop circling a long solenoid carrying alternating current--has confirmed that induction occurs in a region of space effectively free from magnetic field. This again reinforces the idea of vector potential as a physical entity rather than the auxiliary artificial quantity of classical electrodynamics. The present investigation is intended to provide some degree of corroboration of the previous result.The experimental arrangement consists of a ‘special’ transformer containing movable, single turn coils wound onto rectangular frames. The primary coil is powered from a signal generator providing alternating current over a variable frequency range while the secondary output voltage is connected across a C.R.O./precision voltmeter. Measurements of transformer e.m.f. were carried out at several frequencies in the range 100 Hz–20 kHz and with various conditions of shielding around the primary and secondary coils.Certain additional experiments were carried out with a long solenoid and torus solenoid supplied with different core materials. Experimental results for induced e.m.f’s are presented and in special cases correlated with the calculated values of mutual inductance. Overall the results tend to confirm the primacy of vector potential over magnetic field as an explanation of the phenomenon.

Vladimir Alexandr Leus

2013-07-01

38

The zero vector potential mechanism of attosecond absorption

A new mechanism for the absorption of energy during the interaction between an ultra-intense laser pulse and a sharp-edged overdense plasma, which we term the zero vector potential (ZVP) mechanism, is presented. The ZVP-mechanism is a nonponderomotive absorption mechanism that should dominate in the interaction of very strong short laser pulses (a 0?1) with overdense plasmas in the case of sharp density gradients. In the ZVP-mechanism the existence of moving zeroe...

Baeva, T.; Gordienko, S.; Robinson, Apl; Norreys, Pa

2011-01-01

39

Recent Developments of JAEA's Monte Carlo Code MVP for Reactor Physics Applications

This paper describes the recent development status of a Monte Carlo code MVP developed at Japan Atomic Energy Agency. The basic features and capabilities of MVP are overviewed. In addition, new capabilities useful for reactor analysis are also described.

Nagaya, Yasunobu; Okumura, Keisuke; Mori, Takamasa

2014-06-01

40

Deriving Potential Coronal Magnetic Fields from Vector Magnetograms

The minimum-energy configuration for the magnetic field above the solar photosphere is curl-free (hence, by Ampere's law, also current-free), so can be represented as the gradient of a scalar potential. Since magnetic fields are divergence free, this scalar potential obeys Laplace's equation, given an appropriate boundary condition (BC). With measurements of the full magnetic vector at the photosphere, it is possible to employ either Neumann or Dirichlet BCs there. Historically, the Neumann BC was used, since available line-of-sight magnetic field measurements approximated the radial field needed for the Neumann BC. Since each BC fully determines the 3D vector magnetic field, either choice will, in general, be inconsistent with some aspect of the observed field on the boundary, due to the presence of both currents and noise in the observed field. We present a method to combine solutions from both Dirichlet and Neumann BCs to determine a hybrid potential field that minimizes the integrated square of the residu...

Welsch, Brian T

2015-01-01

41

Telediagnostic Assessment of Intelligibility in Dysarthria: A Pilot Investigation of MVP-Online

Background: A most important index of functional impairment in dysarthria is "intelligibility". The "Munich Intelligibility Profile" (MVP) is a computer-based method for the assessment of the intelligibility of dysarthric patients. A multi-user online version of MVP is now available. Aims: To describe the structure of MVP-online and to evaluate…

Ziegler, Wolfram; Zierdt, Andreas

2008-01-01

42

Vector activity and propagule size affect dispersal potential by vertebrates.

Many small organisms in various life stages can be transported in the digestive system of larger vertebrates, a process known as endozoochory. Potential dispersal distances of these "propagules" are generally calculated after monitoring retrieval in experiments with resting vector animals. We argue that vectors in natural situations will be actively moving during effective transport rather than resting. We here test for the first time how physical activity of a vector animal might affect its dispersal efficiency. We compared digestive characteristics between swimming, wading (i.e. resting in water) and isolation (i.e. resting in a cage) mallards (Anas platyrhynchos). We fed plastic markers and aquatic gastropods, and monitored retrieval and survival of these propagules in the droppings over 24 h. Over a period of 5 h of swimming, mallards excreted 1.5 times more markers than when wading and 2.3 times more markers than isolation birds, the pattern being reversed over the subsequent period of monitoring where all birds were resting. Retention times of markers were shortened for approximately 1 h for swimming, and 0.5 h for wading birds. Shorter retention times imply higher survival of propagules at increased vector activity. However, digestive intensity measured directly by retrieval of snail shells was not a straightforward function of level of activity. Increased marker size had a negative effect on discharge rate. Our experiment indicates that previous estimates of propagule dispersal distances based on resting animals are overestimated, while propagule survival seems underestimated. These findings have implications for the dispersal of invasive species, meta-population structures and long distance colonization events. PMID:22419480

van Leeuwen, Casper H A; Tollenaar, Marthe L; Klaassen, Marcel

2012-09-01

43

Conceptual designing of a reduced moderation pressurized water reactor by use of MVP and MVP-BURN

Energy Technology Data Exchange (ETDEWEB)

A conceptual design of a seed-blanket assembly PWR core with a complicated geometry and a strong heterogeneity has been carried forward by use of the continuous-energy Monte Carlo method. Through parametric survey calculations by repeated use of MVP and a lattice burn-up calculation by MVP-BURN, a seed-blanket assembly configuration suitable for a concept of RMWR has been established, by evaluating precisely reactivity, a conversion ratio and a coolant void reactivity coefficient in a realistic computation time on a super computer. (orig.)

Kugo, T. [Japan Atomic Energy Research Inst., Ibaraki-ken (Japan). Dept. of Nuclear Energy System

2001-07-01

44

Conceptual designing of a reduced moderation pressurized water reactor by use of MVP and MVP-BURN

International Nuclear Information System (INIS)

A conceptual design of a seed-blanket assembly PWR core with a complicated geometry and a strong heterogeneity has been carried forward by use of the continuous-energy Monte Carlo method. Through parametric survey calculations by repeated use of MVP and a lattice burn-up calculation by MVP-BURN, a seed-blanket assembly configuration suitable for a concept of RMWR has been established, by evaluating precisely reactivity, a conversion ratio and a coolant void reactivity coefficient in a realistic computation time on a super computer. (orig.)

45

TRR-1/M1 Core Analysis with MVP

International Nuclear Information System (INIS)

Full text: Since early 1990s, the in-core fuel management of TRR-1/M1 has been performed by TRIGAP. This code was specifically developed for reactor physics calculations of the TRIGA-type reactor. However, because of its limitations in geometrical and cross sectional options, the attempt of using other techniques/codes are provoked. Nowadays, the choice of using the Monte Carlo method to perform core analysis becomes more satisfaction with acceptable computational time. The MVP is one of the codes that utilize the Monte Carlo method with continuous-energy library. It is able to explicitly model the problem in 3-D geometry. It also has a burn-up calculation feature called MVP-BURN. The aim of the current work is to apply the MVP code for TRR-1/M1 core analysis. In this paper, the MVP code was verified with the experiment results for the fresh core and some burn-up cores. The calculated-eigenvalue results agree well with the experimental data within an acceptable range of statistical error

46

Potential role of ticks as vectors of bluetongue virus.

When the first outbreak of bluetongue virus serotype 8 (BTV8) was recorded in North-West Europe in August 2006 and renewed outbreaks occurred in the summer of 2007 and again in 2008, the question was raised how the virus survived the winter. Since most adult Culicoides vector midges are assumed not to survive the northern European winter, and transovarial transmission in Culicoides is not recorded, we examined the potential vector role of ixodid and argasid ticks for bluetongue virus. Four species of ixodid ticks (Ixodes ricinus, Ixodes hexagonus, Dermacentor reticulatus and Rhipicephalus bursa) and one soft tick species, Ornithodoros savignyi, ingested BTV8-containing blood either through capillary feeding or by feeding on artificial membranes. The virus was taken up by the ticks and was found to pass through the gut barrier and spread via the haemolymph into the salivary glands, ovaries and testes, as demonstrated by real-time reverse transcriptase PCR (PCR-test). BTV8 was detected in various tissues of ixodid ticks for up to 21 days post feeding and in Ornithodoros ticks for up to 26 days. It was found after moulting in adult Ixodes hexagonus and was also able to pass through the ovaries into the eggs of an Ornithodoros savignyi tick. This study demonstrates that ticks can become infected with bluetongue virus serotype 8. The transstadial passage in hard ticks and transovarial passage in soft ticks suggest that ticks have potential vectorial capacity for bluetongue virus. Further studies are required to investigate transmission from infected ticks to domestic livestock. This route of transmission could provide an additional clue in the unresolved mystery of the epidemiology of Bluetongue in Europe by considering ticks as a potential overwintering mechanism for bluetongue virus. PMID:20358393

Bouwknegt, Chantal; van Rijn, Piet A; Schipper, Jacqueline J M; Hölzel, Dennis; Boonstra, Jan; Nijhof, Ard M; van Rooij, Eugène M A; Jongejan, Frans

2010-10-01

47

Mediterranean fruit fly as a potential vector of bacterial pathogens.

The Mediterranean fruit fly (Ceratitis capitata) is a cosmopolitan pest of hundreds of species of commercial and wild fruits. It is considered a major economic pest of commercial fruits in the world. Adult Mediterranean fruit flies feed on all sorts of protein sources, including animal excreta, in order to develop eggs. After reaching sexual maturity and copulating, female flies lay eggs in fruit by puncturing the skin with their ovipositors and injecting batches of eggs into the wounds. In view of the increase in food-borne illnesses associated with consumption of fresh produce and unpasteurized fruit juices, we investigated the potential of Mediterranean fruit fly to serve as a vector for transmission of human pathogens to fruits. Addition of green fluorescent protein (GFP)-tagged Escherichia coli to a Mediterranean fruit fly feeding solution resulted in a dose-dependent increase in the fly's bacterial load. Flies exposed to fecal material enriched with GFP-tagged E. coli were similarly contaminated and were capable of transmitting E. coli to intact apples in a cage model system. Washing contaminated apples with tap water did not eliminate the E. coli. Flies inoculated with E. coli harbored the bacteria for up to 7 days following contamination. Fluorescence microscopy demonstrated that the majority of fluorescent bacteria were confined along the pseudotrachea in the labelum edge of the fly proboscis. Wild flies captured at various geographic locations were found to carry coliforms, and in some cases presumptive identification of E. coli was made. These findings support the hypothesis that the common Mediterranean fruit fly is a potential vector of human pathogens to fruits. PMID:16000820

Sela, Shlomo; Nestel, David; Pinto, Riky; Nemny-Lavy, Esther; Bar-Joseph, Moshe

2005-07-01

48

Design and Potential of Non-Integrating Lentiviral Vectors

Lentiviral vectors have demonstrated promising results in clinical trials that target cells of the hematopoietic system. For these applications, they are the vectors of choice since they provide stable integration into cells that will undergo extensive expansion in vivo. Unfortunately, integration can have unintended consequences including dysregulated cell growth. Therefore, lentiviral vectors that do not integrate are predicted to have a safer profile compared to integrating vectors and sho...

Aaron Shaw; Kenneth Cornetta

2014-01-01

49

Path integral for Klein-Gordon particle in vector plus scalar Hulthén-type potentials

The Green's function for a Klein-Gordon particle subjected to vector plus scalar Hulthén-type potentials is calculated in the path integral approach. The energy spectrum together with the normalized wave functions of the bound states are deduced. Special cases including the pure vector Hulthén potential, the pure attractive scalar Hulthén potential and the Coulomb potential are also analyzed.

Chetouani, L.; Guechi, L.; Lecheheb, A.; Hammann, T. F.; Messouber, A.

1996-02-01

50

Flux Ropes as Singularities of the Vector Potential

A flux rope is a domain of concentration of the magnetic field $\\textbf{B}$. Insofar as $\\textbf{B}$ outside such a domain is considered as vanishingly small, a flux rope can be described as the core of a singularity of the outer vector potential $\\textbf{A}$, whose topological invariant is the magnetic flux through the rope. By 'topological' it is meant that $\\oint_C\\textbf{A}\\cdot\\mathrm d\\textbf{s}$ measures along any loop $C$ surrounding the flux rope the same constant flux $\\Phi$. The electric current intensity is another invariant of the theory, but non-topological. We show that, in this theoretical framework, the linear force-free field (LFFF) Lundquist model and the non-linear (NLFFF) Gold-Hoyle model of a flux rope exhibit stable solutions distributed over quantized strata of increasing energies (an infinite number of strata in the first case, only one stratum in the second case); each stratum is made of a continuous set of stable states. The lowest LFFF stratum and the unique NLFFF stratum come nume...

Kleman, M

2014-01-01

51

We show that fermion charge fractionalization can take place in a recently proposed chiral gauge model for graphene even in the absence of Kekul\\'e distortion of the graphene honeycomb lattice. We extend the model by adding the coupling of fermions to an external magnetic field and show that the fermion charge can be fractionalized by means of only gauge potentials. It is shown that the chiral fermion charge can also have fractional value. We also relate the fractionalization of the fermion charge to the parity anomaly in an extended Quantum Electrodynamics which involves vector and vector-axial gauge fields.

Obispo, Angel E

2012-01-01

52

Vector potential versus colour charge density in low-x evolution

We reconsider the evolution equations for multigluon correlators derived in hep-ph/9709432. We show how to derive these equations directly in terms of vector potentials (or colour field strength) avoiding the introduction of the concept of colour charge density in the intermediate steps. The two step procedure of deriving the evolution of the charge density correlators followed by the solution of classical equations for the vector potentials is shown to be consistent with direct derivation of evolution for vector potentials. In the process we correct some computational errors of hep-ph/9709432 and present the corrected evolution equations which have a somewhat simpler appearance.

Kovner, A; Kovner, Alex

2000-01-01

53

Vector potential versus color charge density in low-x evolution

We reconsider the evolution equations for multigluon correlators derived by Jalilian-Marian, Kovner, and Weigert. We show how to derive these equations directly in terms of vector potentials (or color field strength) avoiding the introduction of the concept of color charge density in the intermediate steps. The two step procedure of deriving the evolution of the charge density correlators followed by the solution of classical equations for the vector potentials is shown to be consistent with direct derivation of evolution for vector potentials. In the process we correct some computational errors of Jalilian-Marian, Kovner, and Weigert and present the corrected evolution equations which have a somewhat simpler appearance.

Kovner, Alex; Guilherme Milhano, J.

2000-01-01

54

Naturally Occurring Orthopoxviruses: Potential for Recombination with Vaccine Vectors

Orthopoxviruses are being increasingly used as live recombinant vectors for vaccination against numerous infectious diseases in humans, domestic animals, and wildlife. For risk assessments and surveillance, information about the occurrence, distribution and ecology of orthopoxviruses in western Europe is important but has mainly been based on serological investigations. We have examined kidneys, lungs, spleens, and livers of Norwegian small rodents and common shrews (Sorex araneus) for the pr...

Sandvik, Tore; Tryland, Morten; Hansen, Hilde; Mehl, Reidar; Moens, Ugo; Olsvik, Ørjan; Traavik, Terje

1998-01-01

55

MVP sensor planning and modeling system for machine vision

In this paper we present an overview of the MVP sensor planning and modeling system that we have developed. MVP automatically determines camera viewpoints and settings so that object features of interest are simultaneously visible, inside the field-of-view, in-focus and magnified as required. We have analytically characterized the domain of admissible camera locations, orientations and optical settings for each of the above feature detectability requirements. In addition, we have posed the problem in an optimization setting in order to determine viewpoints that simultaneously satisfy all previous requirements. The location, orientation and optical settings of the computer viewpoint are achieved in the employed sensor setup by using sensor calibration models. For this purpose, calibration techniques have been developed that determine the mapping between the parameters that are planned and the parameters that can be controlled in a sensor setup which consists of a camera in a hand-eye arrangement equipped with a lens that has zoom, focus and aperture control. Experimental results are shown of these techniques when all the above feature detectability constraints are included. In order to verify satisfaction of these constraints, camera views are taken from the computed viewpoints by a robot vision system that is positioned and its lens is set according to the results of this method.

Tarabanis, Kostantinos; Tsai, Roger Y.

1992-04-01

56

Vector potential versus colour charge density in low-x evolution

We reconsider the evolution equations for multigluon correlators derived in hep-ph/9709432. We show how to derive these equations directly in terms of vector potentials (or colour field strength) avoiding the introduction of the concept of colour charge density in the intermediate steps. The two step procedure of deriving the evolution of the charge density correlators followed by the solution of classical equations for the vector potentials is shown to be consistent with di...

Kovner, Alex; Milhano, J. Guilherme

1999-01-01

57

Ixodes dammini as a potential vector of human granulocytic ehrlichiosis.

Little is known about the epidemiology and mode of transmission of the agent of human granulocytic ehrlichiosis (HGE). Analyses of an engorged female Ixodes dammini tick removed from an HGE patient and 101 field-collected I. dammini and Dermacentor variabilis from three Wisconsin counties for Borrelia burgdorferi and Ehrlichia phagocytophila/Ehrlichia equi DNA revealed that the patient tick and 7 of 68 I. dammini ticks from Washburn County collected in 1982 and 1991 were positive for ehrlichial DNA; 10 ticks from the same collections were positive for B. burgdorferi. Two specimens (2.2%) were positive for both organisms. Serologic evidence for exposure to the agent of HGE or its relatives was detected in 3 of 25 Lyme disease patients from the upper Midwest. These data argue that I. dammini is a common vector for transmission of both Lyme disease and HGE. PMID:7561173

Pancholi, P; Kolbert, C P; Mitchell, P D; Reed, K D; Dumler, J S; Bakken, J S; Telford, S R; Persing, D H

1995-10-01

58

Severe hypoxia induces chemo-resistance in clinical cervical tumors through MVP over-expression

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Oxygen molecule modulates tumour response to radiotherapy. Higher radiation doses are required under hypoxic conditions to induce cell death. Hypoxia may inhibit the non-homologous end-joining DNA repair through down regulating Ku70/80 expression. Hypoxia induces drug resistance in clinical tumours, although the mechanism is not clearly elucidated. Vaults are ribonucleoprotein particles with a hollow barrel-like structure composed of three proteins: major vault protein (MVP, vault poly(ADP-ribose polymerase, and telomerase associated protein-1 and small untranslated RNA. Over-expression of MVP has been associated with chemotherapy resistance. Also, it has been related to poor outcome in patients treated with radiotherapy alone. The aim of the present study was to assess the relation of Major Vault Protein expression and tumor hypoxia in clinical cervical tumors. MVP, p53 and angiogenesis, together with tumor oxygenation, were determined in forty-three consecutive patients suffering from localized cervix carcinoma. High MVP expression was related to severe hypoxia compared to low MVP expressing tumors (p = 0.022. Tumors over-expressing MVP also showed increased angiogenesis (p = 0.003. Besides it, in this study we show for the first time that severe tumor hypoxia is associated with high MVP expression in clinical cervical tumors. Up-regulation of MVP by hypoxia is of critical relevance as chemotherapy is currently a standard treatment for those patients. From our results it could be suggested that hypoxia not only induces increased genetic instability, oncogenic properties and metastatization, but through the correlation observed with MVP expression, another pathway of chemo and radiation resistance could be developed.

Apolinario Rosa M

2009-08-01

59

Computation of 3-D current driven skin effect problems using a current vector potential

International Nuclear Information System (INIS)

A finite element formulation of current driven eddy current problems in terms of a current vector potential and a magnetic scalar potential is developed. Since the traditional T-? method enforces zero net current in conductors, an impressed current vector potential T0 is introduced in both conducting and nonconducting regions, describing an arbitrary current distribution with the prescribed net current in each conductor. The function T0 is represented by means of edge elements while nodal elements are used to approximate the current vector potential and the magnetic scalar potential. The tangential component of T is set to zero on the conductor/nonconductor interfaces. The method is validated by computing the solution to an axisymmetric problem. Some problems involving a coil with several turns wound around an iron core are solved

60

Development of continuous energy Monte Carlo burn-up calculation code MVP-BURN

International Nuclear Information System (INIS)

Burn-up calculations based on the continuous energy Monte Carlo method became possible by development of MVP-BURN. To confirm the reliably of MVP-BURN, it was applied to the two numerical benchmark problems; cell burn-up calculations for High Conversion LWR lattice and BWR lattice with burnable poison rods. Major burn-up parameters have shown good agreements with the results obtained by a deterministic code (SRAC95). Furthermore, spent fuel composition calculated by MVP-BURN was compared with measured one. Atomic number densities of major actinides at 34 GWd/t could be predicted within 10% accuracy. (author)

61

A vector field method on the distorted Fourier side and decay for wave equations with potentials

We study the Cauchy problem for the one-dimensional wave equation with an inverse square potential. We derive dispersive estimates, energy estimates, and estimates involving the scaling vector field, where the latter are obtained by employing a vector field method on the "distorted" Fourier side. In addition, we prove local energy decay estimates. Our results have immediate applications in the context of geometric evolution problems. The theory developed in this paper is fun...

Donninger, Roland; Krieger, Joachim

2013-01-01

62

Properties of singular vectors using convective available potential energy as final time norm

We study the feasibility of using the singular vector technique to create initial condition perturbations for short-range ensemble prediction systems (SREPS) focussing on predictability of severe local storms and in particular deep convection. For this a new final time semi-norm based on the convective available potential energy (CAPE) is introduced. We compare singular vectors using the CAPE-norm with SVs using the more common total energy (TE) norm for a 2-week summer period in 2007, which ...

Stappers, Roel J. J.; Barkmeijer, J.

2011-01-01

63

International Nuclear Information System (INIS)

The validation research works in BATAN are focused using Monte Carlo method with recent nuclear data on the experimental results. In this paper, the validation results of Monte Carlo method of MVP code on the first criticality experimental of Indonesia Multipurpose Reactor (RSG GAS reactor) are presented. The MVP code is a vectorized and continuous energy Monte Carlo code developed by Japan Atomic Energy Agency (JAEA). The objective this paper is to show the accuracy of the code using recent nuclear data of JEF-3.0, JENDL- 3.3 and ENDF/B-VI.8. The final goal of this research is to use the code as a in-core fuel management code since the code has a module of burn-up calculation (MVP-BURN). SG GAS reactor is a beryllium (Be)-reflected, light-water-moderated and -cooled, 30 MWth (max.) multipurpose reactor. Presently, the reactor uses MTR-type LEU (19.75 w/o) silicide fuel (U3Si2-Al) elements (FEs). On the 10 x 10 core grid positions there are 40 standard FEs (each consisting of 21 fuel plates), eight control elements (CEs, each consisting f 15 fuel plates) initially loaded with 250 and 178.6 g 235U respectively, Beryllium reflector elements and other irradiation facilities. This fuel loading corresponds to a uranium meat density of 2.96 g/cm3. The equilibrium core is achieved through some transition cores with smaller core and lower power. In the first transition core, all FEs and CEs were fresh oxide fuel with same uranium mewere fresh oxide fuel with same uranium meat density of 2.96 g/cm3. Some experiments were carried out in the core, including criticality experiments, as a part of commissioning activity. Since the first core using the fresh fuels, so the core can be used a bench mark core to validate the accuracy of a selected code. In the criticality experiments, there were some types of experiment have been performed as follows: - first criticality by adding FEs and CEs - criticality condition by adding the Beryllium reflector elements - criticality condition by adjustment various positions of six control rods - excess reactivity and total control rod worth In this paper, those criticality experimental results are compared to the calculated results by using the MVP code. The calculated results showed that using the selected nuclear data are very close to the experimental results. For example, the calculated core excess reactivity using JENDL-3.3 is in the range of 8.17 % ?k/k - 8.35 %?k/k. The calculated result is very close to the experimental result of 8.41 %?k/k. It can be concluded that the MVP code with JENDL-3.3 and ENDF/B-VI.8 nuclear data can be applied for the MTR type reactor with bulky Beryllium reflector. (author)

64

Algebraic inversion of the Dirac equation for the vector potential in the non-Abelian case

International Nuclear Information System (INIS)

We study the Dirac equation for spinor wavefunctions minimally coupled to an external field, from the perspective of an algebraic system of linear equations for the vector potential. By analogy with the method in electromagnetism, which has been well-studied, and leads to classical solutions of the Maxwell–Dirac equations, we set up the formalism for non-Abelian gauge symmetry, with the SU(2) group and the case of four-spinor doublets. An extended isospin-charge conjugation operator is defined, enabling the hermiticity constraint on the gauge potential to be imposed in a covariant fashion, and rendering the algebraic system tractable. The outcome is an invertible linear equation for the non-Abelian vector potential in terms of bispinor current densities. We show that, via application of suitable extended Fierz identities, the solution of this system for the non-Abelian vector potential is a rational expression involving only Pauli scalar and Pauli triplet, Lorentz scalar, vector and axial vector current densities, albeit in the non-closed form of a Neumann series. (paper)

65

Calculation of the magnetic vector potential in the TJ-II

International Nuclear Information System (INIS)

The properties of the vector magnetic potential and its usefulness to calculate magnetic fluxes in both stationary and time-dependent conditions are p revised in this report. We have adapted to the TJ-II Flexible Heliac efficient numerical expressions to calculate the vector potential, calculating in addition the magnetic flux with this formalism in circumstances whose complexity makes very convenient the use of the vector potential. The result on induced voltages offer theoretical support to the measurements of induced voltage due to the OH coils in the plasma, like the measurements provided by the loop voltage diagnostic installed in the TJ-II, as well as to the cylindrical approximation of the plasma often used to interpret experimental data. (Author) 11 refs

66

An educational path for the magnetic vector potential and its physical implications

We present an educational path on the magnetic vector potential A addressed to undergraduate students and to pre-service physics teachers. Starting from the generalized Ampere-Laplace law, in the framework of a slowly varying time-dependent field approximation, the magnetic vector potential is written in terms of its empirical referent, i. e. the conduction current. Therefore, once the currents are known, our approach allows a clear and univocal physical determination of A overcoming the mathematical indeterminacy due to the gauge transformations. We have no need to fix a gauge, since for slowly varying time-dependent electric and magnetic fields, the natural gauge for A is the Coulomb one. We stress the difference between our approach and those usually presented in the literature. Finally, a physical interpretation of the magnetic vector potential is discussed and some examples of calculation of A are analysed.

Barbieri, Sara; Giliberti, Marco

2013-01-01

67

Neuroprotective potential of a viral vector system induced by a neurological insult.

Gene transfer into neurons via viral vectors for protection against acute necrotic insults has generated considerable interest. Most studies have used constitutive vector systems, limiting the ability to control transgene expression in a dose-dependent, time-dependent, or reversible manner. We have constructed defective herpes simplex virus vectors designed to be induced by necrotic neurological insults themselves. Such vectors contain a synthetic glucocorticoid-responsive promoter, taking advantage of the almost uniquely high levels of glucocorticoids-adrenal stress steroids-secreted in response to such insults. We observed dose-responsive and steroid-specific induction by endogenous and synthetic glucocorticoids in hippocampal cultures. Induction was likely to be rapid enough to allow transgenic manipulation of relatively early steps in the cascade of necrotic neuron death. The protective potential of such a vector was tested by inclusion of a neuroprotective transgene (the Glut-1 glucose transporter). Induction of this vector by glucocorticoids decreased glutamatergic excitotoxicity in culture. Finally, both exogenous glucocorticoids and excitotoxic seizures induced reporter gene expression driven from a glucocorticoid-responsive herpes simplex virus vector in the hippocampus in vivo. PMID:10908682

Ozawa, C R; Ho, J J; Tsai, D J; Ho, D Y; Sapolsky, R M

2000-08-01

68

C595 antibody: A potential vector for targeted alpha therapy

International Nuclear Information System (INIS)

Full text: Mucins are high molecular-weight heavily glycosylated glycoproteins with many oligosaccharide side-chains, linked to a protein backbone called apomucin. A total of 19 different mucin genes (MUC1-MUC4, MUC5B, MUC5AC, MUC6-MUC18) have been identified to date. Mucins are present on the surface of most epithelial cells and play a role in their protection and lubrication. In cancer cells the mucin molecule becomes altered, thus representing an important target for diagnosis and therapy. Urinary epithelial mucin1 (MUC1) is found to be frequently up-regulated and abnormally glycosylated in a number of common malignancies, including breast, bladder, colon, ovarian and gastric cancer. The monoclonal antibody C595 is an IgG3 murine MAb raised against the protein core of human MUC1. Epitope mapping has shown that C595 recognizes a tetrapeptide motif (RPAP) within the protein core of MUC1 mucin that contains a large domain of multiples of a highly conserved 20-amino-acid-repeat sequence (PDTRPAPGSTAPPAHGVTSA). This antibody has previously been radiolabelled with 99mTc and 111In and used for imaging a range of tumour types including ovary, breast and bladder. The antibody has also been radiolabelled with 67Cu and 188Re for the therapy of superficial bladder cancer. More recently we have investigated the pre-clinical use of the C595 antibody for targeted alpha therapy using 213Bi which emits alpha particles with highp>Bi which emits alpha particles with high linear energy transfer (LET), short range (80 m) radiation and has a short physical half-life of 45.6 minutes. Alpha particles are some 7300 times heavier than beta particles and in theory, following binding of an alpha immunocongugates to the target, a large fraction of the alpha particle energy is delivered to cancer cells, with minimal concomitant radiation of normal tissues. 213Bi was produced from the 225Ac/213Bi generator. For antibody conjugation the chelator, cyclic diethylenetriaminepentacetic acid anhydride (DTPA) was used. Initial experimental studies have concentrated on the targeted therapy of carcinoma of the prostate, pancreas and ovary. On 120 paraffin embedded specimens from patients who underwent radical retro-pubic prostatectomy or trans-urethralresection of the prostate for primary untreated carcinoma of the pancreas MUC1 expression was detected in 58% primary Ca prostate tissues and 90% lymph node metastases but not in normal prostates or benign tissues. The 213Bi-C595 conjugate demonstrated cell killing in PC-3 and DU 145 cell lines isolated from human prostatic adenocarcinoma. Other results indicate that 213Bi-C595 targeting efficacy is in accordance with the expression of MUC1 in three pancreatic cancer cell clusters CFPAC-1, PANC-1 and CAPAN-1 and demonstrated effective toxicity of tumour spheroids of up to 100 m in diameter. When administered to tumour bearing mice at 333 MBq/kg the c595 alpha conjugate caused significant tumour growth delay, compared with the non-specific control at after 16 weeks. Similar results have been obtained in monolayers and cell clusters of the ovarian OVCAR-3 cell line. We believe this antibody conjugate offers great potential for targeted alpha therapy of prostatic, pancreatic and ovarian tumours. (author)

69

Ctenocephalides felis an in vitro potential vector for five Bartonella species.

The blood-sucking arthropod Ctenocephalides felis has been confirmed as a vector for Bartonella henselae and is a suspected vector for Bartonella clarridgeiae, Bartonella quintana and Bartonella koehlerae in Bartonella transmission to mammals. To understand the absence of other Bartonella species in the cat flea, we have developed an artificial flea-feeding method with blood infected successively with five different Bartonella species. The results demonstrated the ability of these five Bartonella species to persist in C. felis suggesting an ability of fleas to be a potential vector for several Bartonella species. In addition, we demonstrated a regurgitation of Bartonella DNA in uninfected blood used to feed C. felis thus suggesting a potential horizontal transmission of Bartonella through C. felis saliva. On the contrary, no vertical transmission was detected in these artificial conditions. PMID:23200028

Bouhsira, Emilie; Ferrandez, Yann; Liu, MaFeng; Franc, Michel; Boulouis, Henri-Jean; Biville, Francis

2013-03-01

70

International Nuclear Information System (INIS)

The RTP is a light-water moderated and pool-type TRIGA MARK II reactor with power capacity of 1MWt. It was built in 1979 and attained the first criticality on 28 June 1982. The RTP was designed mainly for neutron activation analysis, small angle neutron scattering, neutron radiography, radioisotope production, education and training purposes. It uses standard TRIGA fuel developed by General Atomic in which the zirconium hydride moderator is homogeneously combined with enriched uranium. It has a cylindrical core with which possibility of locating 127 of fuel elements. Both of the coolant and moderator uses light water system and the reflector is made of high purity graphite. Because of its relatively small power, it uses natural convection for its cooling system. To ensure the integrity of the core, fuel shuffling have been carried out several times. Until now, there were 12 configurations of the core, the most recent change being in July 2006. This paper will describe the RTP core calculation using the Monte Carlo MVP code system. VP is a general multi-purpose Monte Carlo code for neutron and photon transport calculation in order to have an accurate and fast Monte Carlo simulation of neutron and photon transport problems. The MVP Monte Carlo code calculation is based on the continuous energy method. This code is capable of adopting an accurate physics model, geometry description and variance reduction technique. When compared to the conventional scalar method, this coto the conventional scalar method, this code could achieve higher computation speed by up to a factor of 10 on the vector super-computer. The RTP core has been modelled using cylinder geometry along the z-coordinate geometry with the MVP code system while its material cross section data is calculated beforehand. The JENDL3.3 data library was used in the whole calculation. The objectives of the calculation are to calculate the multiplication factor values (keff), fission density and flux distribution from the tally data. The calculation also gives control rod worth value and comparison with experimental data was made to evaluate the safety of the reactor. (author)

71

Small hive beetle, Aethina tumida, is a potential biological vector of honeybee viruses.

The small hive beetle (SHB) is a parasite and scavenger of honeybee colonies. Here, we conducted laboratory experiments to investigate the potential of SHB as a vector of honeybee viruses. Using RT-PCR methods, Deformed Wing Virus (DWV) was detected in adult SHBs that: 1) were fed with dead workers ...

72

Rippled graphene in an in-plane magnetic field: effects of a random vector potential.

We report measurements of the effects of a random vector potential generated by applying an in-plane magnetic field to a graphene flake. Magnetic flux through the ripples cause orbital effects: Phase-coherent weak localization is suppressed, while quasirandom Lorentz forces lead to anisotropic magnetoresistance. Distinct signatures of these two effects enable the ripple size to be characterized. PMID:21230858

Lundeberg, Mark B; Folk, Joshua A

2010-10-01

73

Comment on ‘An educational path for the magnetic vector potential and its physical implications’

International Nuclear Information System (INIS)

In their recent paper, Barbieri et al (2013 Eur. J. Phys. 34 1209) proposed an educational path for the magnetic vector potential. In this comment I point out that this educational path involves several inconsistencies and is therefore unattractive from a pedagogical point of view. (letters and comments)

74

International Nuclear Information System (INIS)

In this reply we respond to the comment made by Heras on our paper (Barbieri et al 2013 Eur. J. Phys. 34 1209), in which we presented an educational path on the magnetic vector potential A, aimed at undergraduate students and pre-service physics teachers. (letters and comments)

75

Criticality analysis of KUCA critical experiments by MVP

International Nuclear Information System (INIS)

Criticality analysis of critical experiments at Kyoto University Critical Assembly (KUCA) have been performed by using the continuous energy Monte Carlo code MVP together with the latest evaluated nuclear data library JENDL-3.2. In this study, 14 polyethylene moderated/reflected cores and 12 light-water moderated/reflected cores were selected as the benchmark experiments. The C/E values of the effective multiplication factors for the polyethylene moderated/reflected cores were 1.010 - 1.020, whereas the C/E values for the light-water moderated/reflected cores were 0.997 - 1.006. The difference between the C/E values obtained using JENDL-3.2 and JENDL-3.1 was 0.5 - 2.3%. This rather significant difference was further investigated based on the decomposition of infinite multiplication factors into contributing nuclides and reactions, and it has been found that this is mainly due to the difference in the epithermal capture cross section of U-235 between the two libraries. (author)

76

Bound states of the Dirac equation with vector and scalar Scarf-type potentials

International Nuclear Information System (INIS)

Solving the Dirac equations with equal Scarf-type scalar and vector potentials by the method of the supersymmetric quantum mechanics, shape invariance approach and the alternative method, we obtain the exact energy equations and unnormalized wavefunctions for the s-wave bound states. Some interesting results including the standard Scarf II, generalized Poeschl-Teller and Poeschl-Teller II potentials are also discussed

77

Bound states of the Dirac equation with vector and scalar Scarf-type potentials

Energy Technology Data Exchange (ETDEWEB)

Solving the Dirac equations with equal Scarf-type scalar and vector potentials by the method of the supersymmetric quantum mechanics, shape invariance approach and the alternative method, we obtain the exact energy equations and unnormalized wavefunctions for the s-wave bound states. Some interesting results including the standard Scarf II, generalized Poeschl-Teller and Poeschl-Teller II potentials are also discussed.

Zhang Xuecai [Department of Earth Sciences, Nanjing University, Nanjing 210093 (China)]. E-mail: zxc001@slof.com; Liu Quanwen [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum Institute, Chengdu 610500 (China)]. E-mail: liu005777@yahoo.com.cn; Jia Chunsheng [State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum Institute, Chengdu 610500 (China)]. E-mail: chshjia@263.net; Wang Lizhi [Research Institute of Exploration and Development, Zhongyuan Oilfield, Puyang 457001, Henan Province (China)

2005-06-06

78

Observational tests of models for a relativistic nucleon bound in scalar and vector potentials

International Nuclear Information System (INIS)

A survey is made of possible methods to verify features of the nuclear single-particle model in which the nucleon is assumed to move relativistically in a field of scalar character plus one given as the fourth component of a four-vector (sigma + ? model). Electromagnetic and weak probes are considered, and sensitivity to the nucleon effective mass - considerably changed in the precence of the scalar plus vector fields - is sought. A number of direct effects are in large measure lost because terms involving the mass usually involve gradient operators as well, and these tend to give little contribution when acting on the potentials in the nuclear interior where they are large but flat. A promising candidate as a probe is the ratio of induced pseudoscalar coupling constant to axial vector coupling constant, which is proportional to the effective mass. (orig.)

79

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english The main target of Malaysian Palm Oil Board (MPOB) genetic engineering programme is to produce high oleate transgenic palms. The availability of effective transformation vector is one of the pre-requisites for genetic manipulation of oil palm through recombinant DNA technology. Here, we describe the [...] construction of a series of transformation vectors that have a maize ubiquitin promoter (UbiPro)-driven bar gene for selection of transformants on herbicide (Basta or Bialaphos), and mesocarp-specific promoter (MSP1) for expression of the transgenes [antisense palmitoyl-ACP-thioesterase (PAT) and sense ?-ketoacyl-ACP-synthase II (KASII) and sense ?9-stearoyl-ACP-desaturase (SAD)] potentially responsible for high oleate content in oil palm mesocarp. The transformation vectors constructed in this study are suitable for use in both particle bombardment (biolistic) and Agrobacterium-based transformation protocols.

Mat Yunus Abdul, Masani; Ghulam Kadir Ahmad, Parveez.

2008-07-15

80

Potential of adenovirus and baculovirus vectors for the delivery of shRNA against morbilliviruses.

Morbilliviruses are important pathogens of humans, ruminants, carnivores and marine mammals. Although good vaccines inducing long-term immunity are available, recurrent outbreaks of measles, canine distemper and peste des petits ruminants (PPR) are observed. In control strategies, antivirals thus could be useful to confine virus spread and application of interfering RNAs is a promising approach, provided they can be delivered efficiently into the host cells. We have constructed recombinant adenovirus and baculovirus vectors expressing short hairpin RNAs (shRNAs) against the PPR virus (PPRV) and compared them in vitro. It was found that both recombinant viruses inhibited PPRV replication with the baculovirus vector, which inhibited generation of infectious progeny by more than 2 log10 and the nucleoprotein expression of PPRV by 73%, being the more efficient. The results show that baculoviral shRNA-expressing vectors have the potential for therapeutic use against morbillivirus infections. PMID:21356246

Nizamani, Zaheer Ahmed; Keil, Gunther M; Albina, Emmanuel; Holz, Carine; Minet, Cécile; Kwiatek, Olivier; Libeau, Geneviève; Servan de Almeida, Renata

2011-04-01

81

Matrix representation of vector potential: DVR and TDDVR formulations and dynamics

The inclusion of the geometric phase effects through the addition of vector potential is well known. We present the formulation of DVR and TDDVR matrix equations for any 2-D system with vector potential. The effective potential appears as the complex hermitian matrix in the DVR/TDDVR representation where in case of TDDVR, matrices associated with "classical" momentum also plays an important role in the dynamics. We derive the rigorous expressions of "classical" equations of motion from Dirac-Frenkel variational principle without introducing the "classical" path as such. Numerical calculations by using DVR/TDDVR equations have been carried out to obtain the signature of geometric phase on the reactive and non-reactive scattering processes. TDDVR appears to be better compromise between speed and accuracy than traditional quantum dynamics numerical methodologies (DVR/FFT).

Puzari, Panchanan; Sarkar, Biplab; Adhikari, Satrajit

2006-05-01

82

Matrix representation of vector potential: DVR and TDDVR formulations and dynamics

International Nuclear Information System (INIS)

The inclusion of the geometric phase effects through the addition of vector potential is well known. We present the formulation of DVR and TDDVR matrix equations for any 2-D system with vector potential. The effective potential appears as the complex hermitian matrix in the DVR/TDDVR representation where in case of TDDVR, matrices associated with 'classical' momentum also plays an important role in the dynamics. We derive the rigorous expressions of 'classical' equations of motion from Dirac-Frenkel variational principle without introducing the 'classical' path as such. Numerical calculations by using DVR/TDDVR equations have been carried out to obtain the signature of geometric phase on the reactive and non-reactive scattering processes. TDDVR appears to be better compromise between speed and accuracy than traditional quantum dynamics numerical methodologies (DVR/FFT)

83

Validation of the Monte Carlo code MVP on the first criticality of Indonesian multipurpose reactor

International Nuclear Information System (INIS)

The validation research works in BATAN are focused using Monte Carlo codes with recent nuclear data on the experimental results. In this paper, the validation results of Monte Carlo code MVP on the first criticality experimental of Indonesia Multipurpose Reactor (RSG GAS reactor) are presented. The MVP code is a continuous energy Monte Carlo code developed by Japan Atomic Energy Research Institute (JAERI). The objective this paper is to show the accuracy of the code using recent nuclear data of JEF-3.0, JENDL-3.3 and ENDF/B-VI.8. The final goal of this research is to use the code as an in-core fuel management code since the code has a module of burn-up calculation (MVP-BURN). The MVP calculations with the three libraries produced keff values with excellent agreement to experiment data since the maximum differences are less than 0.5%. For the total control rod worth, the maximum difference is 3.6%. Systematically, ENDF/B-VI.8 library gave a maximum difference compared with other libraries. Therefore, the MVP code with recent libraries can be applied for the MTR type reactor with bulky Beryllium reflector. (author)

84

International Nuclear Information System (INIS)

A code system has been developed to produce neutron cross section libraries for the MVP continuous energy Monte Carlo code from an evaluated nuclear data library in the ENDF format. The code system consists of 9 computer codes, and can process nuclear data in the latest ENDF-6 format. By using the present system, MVP neutron cross section libraries for important nuclides in reactor core analyses, shielding and fusion neutronics calculations have been prepared from JENDL-3.1, JENDL-3.2, JENDL-FUSION file and ENDF/B-VI data bases. This report describes the format of MVP neutron cross section library, the details of each code in the code system and how to use them. (author)

85

Scattering and bound states of fermions in a mixed vector–scalar smooth step potential

International Nuclear Information System (INIS)

The scattering of a fermion in the background of a smooth step potential is considered with a general mixing of vector and scalar Lorentz structures with the scalar coupling stronger than or equal to the vector coupling. Charge-conjugation and chiral-conjugation transformations are discussed and it is shown that a finite set of intrinsically relativistic bound-state solutions appears as poles of the transmission amplitude. It is also shown that those bound solutions disappear asymptotically as one approaches the conditions for the realization of the so-called spin and pseudospin symmetries in a four-dimensional space–time. - Highlights: • Scattering and bound states of fermions in a kink-like potential. • No pair production despite the high localization. • No bounded solution under exact spin and pseudospin symmetries

86

Stochastic and Deterministic Vector Chromatography of Suspended Particles in 1D-Periodic Potentials

We present a comprehensive description of vector chromatography that includes deterministic and stochastic transport in 1D-periodic free-energy landscapes, with both energetic and entropic contributions, and highlights the parameters governing the deflection angle, i.e. the Peclet number and the partition ratio. We also investigate the dependence of the deflection angle on the shape of the free-energy landscape by varying the width of the linear transitions in an otherwise dichotomous potential. Finally, we present experimental results obtained in a microfluidic system in which gravity drives the suspended particles and, in combination with a bottom surface patterned with shallow rectangular grooves, creates a periodic landscape of (potential) energy barriers. The experiments validate the model and demonstrate that a simple, passive microdevice can lead to vector separation of colloidal particles based on both size and density.

Bernate, Jorge A

2011-01-01

87

Comparison of gamma-ray skyshine dose evaluation performance among Monte Carlo codes; EGS, MVP, MCNP

International Nuclear Information System (INIS)

In applying the Monte Carlo method to skyshine calculations, examinations are required on the validity of the calculation methods such as variance reductions and the accuracy of the calculation. In this study, using typical codes of the continuous energy Monte Carlo method, i.e. EGS5, MVP2, and MCNP5, analyses were conducted of Kansas State University skyshine benchmark experiment. And the calculation results of the gamma-ray skyshine doses by these codes were compared with each other. The following results were obtained: (1) For the gamma-ray skyshine dose calculations using Monte Carlo codes, the method of using mass energy absorption coefficients as conversion factors was effective. And under this experimental condition, dose calculations were possible for about 50,000,000 histories without variation reduction techniques. (2) The photon spectrum calculation results by EGS5, MVP2, and MCNP5 were in good agreement. (3) The dose calculation results by EGS5 and MCNP5 were in good agreement and agreed well with the experimental values. (4) In the case of MVP2 dose calculations, if dose conversion was performed in multi-group form, about twenty percent error was observed. However, if dose conversion was performed using dosimetry files, the calculation results by MVP2 were significantly improved and agreed well with those by EGS5 and MCNP5, and experimental values. From these results, it was ascertained that EGS5, MVP2, and MCNP5 can evaluate gamma-ray skyshine doses withcan evaluate gamma-ray skyshine doses with sufficient accuracy to the same extent. In the case of MVP2, however, dose calculations using dosimetry files which are transformed from dose conversion factors are recommended. (author)

88

A Proposal of Potentially Meaningful Material for Teaching of Vector Mechanics

Directory of Open Access Journals (Sweden)

Full Text Available This paper presents didactic solutions to the Vector Mechanics subject, which aims to teach the calculation and the representation of the acting forces on a given particle in space. It is about developed and applied activities in GeoGebra software, called potentially meaningful materials. The whole proposal was based on MLT?Meaningful Learning Theory, proposed by David Ausubel, in order to contribute to a more efficient learning in general disciplines of engineering courses.

Bruno Nunes Myrrha Ribeiro

2014-11-01

89

Chikungunya Viral Fitness Measures within the Vector and Subsequent Transmission Potential

Given the recent emergence of chikungunya in the Americas, the accuracy of forecasting and prediction of chikungunya transmission potential in the U.S. requires urgent assessment. The La Reunion-associated sub-lineage of chikungunya (with a valine substitution in the envelope protein) was shown to increase viral fitness in the secondary vector, Ae. albopictus. Subsequently, a majority of experimental and modeling efforts focused on this combination of a sub-lineage of the East-Central-South A...

Christofferson, Rebecca C.; Chisenhall, Daniel M.; Wearing, Helen J.; Mores, Christopher N.

2014-01-01

90

Enhancing the clinical potential of AAV vectors by capsid engineering to evade pre-existing immunity

Directory of Open Access Journals (Sweden)

Full Text Available Vectors based on adeno-associated viruses have shown considerable promise in both preclinical models and increasingly in clinical trials. However, one formidable challenge is pre-existing immunity due to widespread exposure to numerous AAV variants and serotypes within the human population, which affect efficacy of clinical trials due to the accompanying high levels of anti-capsid neutralizing antibodies. Transient immunosuppression has promise in mitigating cellular and humoral responses induced by vector application in naïve hosts, but cannot overcome the problem that pre-existing neutralizing antibodies pose towards the goal of safe and efficient gene delivery. Shielding of AAV from antibodies, however, may be possible by covalent attachment of polymers to the viral capsid or by encapsulation of vectors inside biomaterials. In addition, there has been considerable progress in using rational mutagenesis, combinatorial libraries, and directed evolution approaches to engineer capsid variants that are not recognized by anti-AAV antibodies generally present in the human population. While additional progress must be made, such strategies, alone or in combination with immunosuppression to avoid de novo induction of antibodies, have strong potential to significantly enhance the clinical efficacy of AAV vectors.

DavidSchaffer

2011-10-01

91

The first autochthonous Leishmania infection in Australia was reported by Rose et al. (2004) and the parasite was characterised as a unique species. The host was the red kangaroo (Macropus rufus) but the transmitting vector was unknown. To incriminate the biological vector, insect trapping by a variety of methods was undertaken at two field sites of known Leishmania transmission. Collected sand flies were identified to species level and were screened for Leishmania DNA using a semi-quantitative real-time PCR. Collections revealed four species of sand fly, with a predominance of the reptile biter Sergentomyia queenslandi (Hill). However, no Leishmania-positive flies were detected. Therefore, alternative vectors were investigated for infection, giving startling results. Screening revealed that an undescribed species of day-feeding midge, subgenus Forcipomyia (Lasiohelea) Kieffer, had a prevalence of up to 15% for Leishmania DNA, with high parasitemia in some individuals. Manual gut dissections confirmed the presence of promastigotes and in some midges material similar to promastigote secretory gel, including parasites with metacyclic-like morphology. Parasites were cultured from infected midges and sequence analysis of the Leishmania RNA polymerase subunit II gene confirmed infections were identical to the original isolated Leishmania sp. Phylogenetic analysis revealed the closest known species to be Leishmania enriettii, with this and the Australian species confirmed as members of Leishmania sensu stricto. Collectively the results strongly suggest that the day-feeding midge (F. (Lasiohelea) sp. 1) is a potential biological vector of Leishmania in northern Australia, which is to our knowledge the first evidence of a vector other than a phlebotomine sand fly anywhere in the world. These findings have considerable implications in the understanding of the Leishmania life cycle worldwide. PMID:21251914

Dougall, Annette M; Alexander, Bruce; Holt, Deborah C; Harris, Tegan; Sultan, Amal H; Bates, Paul A; Rose, Karrie; Walton, Shelley F

2011-04-01

92

A GaAs vector processor based on parallel RISC microprocessors

A vector processor architecture based on the development of a 32-bit microprocessor using gallium arsenide (GaAs) technology has been developed. The McDonnell Douglas vector processor (MVP) will be fabricated completely from GaAs digital integrated circuits. The MVP architecture includes a vector memory of 1 megabyte, a parallel bus architecture with eight processing elements connected in parallel, and a control processor. The processing elements consist of a reduced instruction set CPU (RISC) with four floating-point coprocessor units and necessary memory interface functions. This architecture has been simulated for several benchmark programs including complex fast Fourier transform (FFT), complex inner product, trigonometric functions, and sort-merge routine. The results of this study indicate that the MVP can process a 1024-point complex FFT at a speed of 112 microsec (389 megaflops) while consuming approximately 618 W of power in a volume of approximately 0.1 ft-cubed.

Misko, Tim A.; Rasset, Terry L.

93

ASPECTS REGARDING THE FACEBOOK USER IN ROMANIA AS A POTENTIAL DESTINATION IMAGE - VECTOR

Directory of Open Access Journals (Sweden)

Full Text Available The Internet’s rapid development from the 1.0 version to the 2.0 one has triggered the appearance of social networks. Facebook is Illustrative of them due to the number of users it attracts and its international range of dispersion. Although a beginner in communication, Facebook Romania is prone to contribute highly to the “content generator” market in what concerns its users. In order to create or maintain a brand’s positive image it is necessary to know some elements regarding the demographic aspects of the target public, and its attitudes, predilections or behaviours in general. Thus, web pages created on Facebook can “transform” its users into fans and there is a possibility that afterwards these fans become image -vectors by way of the delivered experiences. This article tries to study the fundamental elements that could make up the profile of a user from the targeted group as a potential destination image- vector.

MIHAIL-CRISTIAN DI?OIU

2011-01-01

94

On the fields of a torus and the role of the vector potential

International Nuclear Information System (INIS)

A toroidal current distribution has nonvanishing exterior vector potential A, but zero exterior field B=?xA=0. This property, together with the absence of fringing fields as in a cylindrical solenoid, makes it convenient for studies involving the vector potential in a field-free region, such as the Aharonov--Bohm effect, or the effect of A in a Josephson junction. We present an immediate general result of magnetostatics, and use it to easily compute A for a torus, to visualize the static vector potential for any current distribution, and to show how one can construct a current distribution to produce any desired A. When the torus current I varies in time, nonzero quasistatic fields E(t) and B(t) are produced (E??I/r3 and B??2I/r2). Radiation is also produced, with the radiation pattern of an electric dipole. The torus provides a counterexample to the common erroneous notion that if all multipole moments of a current distribution vanish then quasistatic fields and radiation must also vanish. We then formulate Maxwell's equations in a way that obviates the role of gauge transformations. This ''gauge irrelevant'' form clarifies the relation of potentials to current sources, isolating the role of the transverse part of A. The general result from magnetostatics is extended to time-varying sources, revealing a seldom recognized symmetry of Maxwell's equations, and showing how one can visualize A for an arbitrary time-dependent currenan arbitrary time-dependent current source. copyright 1995 American Association of Physics Teachers

95

International Nuclear Information System (INIS)

JNES has been developing an integrated depletion code, named MVP-ORBURN, by means of combining the continuous energy Monte Carlo code MVP and point depletion code ORIGEN2. The present effort focuses the improvement of prediction accuracies of the nuclide composition of a spent LWR fuel and the evaluation of the burnup credit on criticality safety evaluation for the safety regulation. A detailed modeling of heterogeneous structure of the fuel assemblies, including control rods, gadolinium fuels etc. is achieved, and thereby stable and reliable techniques and latest nuclear data libraries for the depletion analysis are established. The accuracy of MVP-ORBURN for the nuclide composition analysis of spent fuel was validated against typical post irradiation data. For the PWR fuel, the MVP-ORBURN analysis showed sufficient accuracy, i.e. the differences of the calculated values to the experimentally measured values (C/E ratios) were less than 10% for the major actinide concentrations. On the other hand, for the BWR fuel it was suggested that further developments were required, because differences of the C/Es for the few actinides exceeded over 15%. Therefore new calculation schemes to include the axially distributed void fractions and the sophisticated allocations of burnable poison gadolinium were introduced, and the C/E differences were reduced to nearly 10%. Application studies were also made for the analysis of spent fuel composition and the evaluation of burnup credit ition and the evaluation of burnup credit with a transport cask containing spent fuels, mainly for the uncertainties and their causes. It revealed that the PWR fuel composition predicted by ORIGEN-2 was conservative especially for low burnup conditions compared with the realistic composition predicted by MVP-ORBURN. It is also confirmed that the uncertainty associated with defining acceptable ranges of burnup that must be specified an operation condition for the facility were another important causes of uncertainties. (author)

96

Chikungunya viral fitness measures within the vector and subsequent transmission potential.

Given the recent emergence of chikungunya in the Americas, the accuracy of forecasting and prediction of chikungunya transmission potential in the U.S. requires urgent assessment. The La Reunion-associated sub-lineage of chikungunya (with a valine substitution in the envelope protein) was shown to increase viral fitness in the secondary vector, Ae. albopictus. Subsequently, a majority of experimental and modeling efforts focused on this combination of a sub-lineage of the East-Central-South African genotype (ECSA-V)-Ae. albopictus, despite the Asian genotype being the etiologic agent of recent chikungunya outbreaks world-wide. We explore a collection of data to investigate relative transmission efficiencies of the three major genotypes/sub-lineages of chikungunya and found difference in the extrinsic incubation periods to be largely overstated. However, there is strong evidence supporting the role of Ae. albopictus in the expansion of chikungunya that our R0 calculations cannot attribute to fitness increases in one vector over another. This suggests other ecological factors associated with the Ae. albopictus-ECSA-V cycle may drive transmission intensity differences. With the apparent bias in literature, however, we are less prepared to evaluate transmission where Ae. aegypti plays a significant role. Holistic investigations of CHIKV transmission cycle(s) will allow for more complete assessment of transmission risk in areas affected by either or both competent vectors. PMID:25310016

Christofferson, Rebecca C; Chisenhall, Daniel M; Wearing, Helen J; Mores, Christopher N

2014-01-01

97

International Nuclear Information System (INIS)

The solution of Grad-Shafranov equation determines the stationary behavior of fusion plasma inside a tokamak. To solve the equation it is necessary to know the toroidal current density profile. Recent works show that it is possible to determine a magnetohydrodynamic (MHD) equilibrium with reversed current density (RCD) profiles that presents magnetic islands. In this work we show analytical MHD equilibrium with a RCD profile and analyze the structure of the vacuum vector potential associated with these equilibria using the virtual casing principle

98

Spinless particles in the field of unequal Scalar-Vector Yukawa potentials

We present analytical bound state solutions of the spin-zero Klein-Gordon (KG) particles in the field of unequal mixture of scalar and vector Yukawa potentials within the framework of the approximation scheme to the centrifugal potential term for any arbitrary -state. The approximate energy eigenvalues and unnormalized wave functions are obtained in closed forms using a simple shortcut of the Nikiforov-Uvarov (NU) method. Further, we solve the KG-Yukawa problem for its exact numerical energy eigenvalues via amplitude phase (AP) method to test the accuracy of the present solutions found by using the NU method. Our numerical tests using energy calculations demonstrate the existence of inter-dimensional degeneracy amongst energy states of the KG-Yukawa problem. The dependence of the energy on the dimension is numerically discussed for spatial dimensions

Hamzavi, Majid; Thylwe, Karl-Erik

2013-01-01

99

Potential-field estimation from satellite data using scalar and vector Slepian functions

In the last few decades a series of increasingly sophisticated satellite missions has brought us gravity and magnetometry data of ever improving quality. To make optimal use of this rich source of information on the structure of Earth and other celestial bodies, our computational algorithms should be well matched to the specific properties of the data. In particular, inversion methods require specialized adaptation if the data are only locally available, their quality varies spatially, or if we are interested in model recovery only for a specific spatial region. Here, we present two approaches to estimate potential fields on a spherical Earth, from gradient data collected at satellite altitude. Our context is that of the estimation of the gravitational or magnetic potential from vector-valued measurements. Both of our approaches utilize spherical Slepian functions to produce an approximation of local data at satellite altitude, which is subsequently transformed to the Earth's spherical reference surface. The ...

Plattner, Alain

2013-01-01

100

Feeding behaviour of potential vectors of West Nile virus in Senegal

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background West Nile virus (WNV is a widespread pathogen maintained in an enzootic cycle between mosquitoes and birds with occasional spill-over into dead-end hosts such as horses and humans. Migratory birds are believed to play an important role in its dissemination from and to the Palaearctic area, as well as its local dispersion between wintering sites. The Djoudj Park, located in Senegal, is a major wintering site for birds migrating from Europe during the study period (Sept. 2008- Jan. 2009. In this work, we studied the seasonal feeding behaviour dynamics of the potential WNV mosquito vectors at the border of the Djoudj Park, using a reference trapping method (CDC light CO2-baited traps and two host-specific methods (horse- and pigeon-baited traps. Blood meals of engorged females were analysed to determine their origin. Results Results indicated that Culex tritaeniorhynchus and Cx. neavei may play a key role in the WNV transmission dynamics, the latter being the best candidate bridging-vector species between mammals and birds. Moreover, the attractiveness of pigeon- and horse-baited traps for Cx. neavei and Cx. tritaeniorhynchus varied with time. Finally, Cx. tritaeniorhynchus was only active when the night temperature was above 20°C, whereas Cx. neavei was active throughout the observation period. Conclusions Cx. neavei and Cx. tritaeniorhynchus are the main candidate vectors for the transmission of WNV in the area. The changes in host attractiveness might be related to variable densities of the migratory birds during the trapping period. We discuss the importance of these results on the risk of WNV transmission in horses and humans.

Konaté Lassana

2011-06-01

101

Survey of the relative prevalence of potential yellow fever vectors in north-west Nigeria.

The yellow fever epidemic in Nigeria in 1969-70 emphasized the lack of data concerning the possible importance of Aedes aegypti and other Stegomyia mosquitos as vectors. An entomological survey was therefore undertaken in September 1973 in 6 areas in the north-west of Nigeria to determine the prevalence of Stegomyia populations in the villages. An examination of over 6 700 water pots showed that 11-53% contained A. aegypti larvae, and in some areas larvae of A. vittatus were found in up to 18% of pots. In villages in the relatively dry Sudan savanna neither leaf axils nor tree-holes were important Stegomyia larval habitats, but in the more southern Kontagora area of the wetter northern Guinea savanna, these habitats were probably important breeding sites. In the early evening the most abundant man-biting mosquito in the villages was A. aegypti. A. vittatus was also caught at bait in some villages. It was concluded that the only potential yellow fever vectors in the area were A. aegypti and A. vittatus. There were large populations of A. aegypti, closely associated with man, in all the areas surveyed, but they should not present a risk of yellow fever transmission unless the disease were to be introduced into the area by man, or unless virus reservoirs, such as monkeys, were also present. Although monkeys were common in the Kontagora area they were rare in the Sudan savanna. PMID:4156499

Service, M W

1974-01-01

102

Potentiation of anthrax vaccines using protective antigen-expressing viral replicon vectors.

DNA vaccines require improvement for human use because they are generally weak stimulators of the immune system in humans. The efficacy of DNA vaccines can be improved using a viral replicon as vector to administer antigen of pathogen. In this study, we comprehensively evaluated the conventional non-viral DNA, viral replicon DNA or viral replicon particles (VRP) vaccines encoding different forms of anthrax protective antigen (PA) for specific immunity and protective potency against anthrax. Our current results clearly suggested that these viral replicon DNA or VRP vaccines derived from Semliki Forest virus (SFV) induced stronger PA-specific immune responses than the conventional non-viral DNA vaccines when encoding the same antigen forms, which resulted in potent protection against challenge with the Bacillus anthracis strain A16R. Additionally, the naked PA-expressing SFV replicon DNA or VRP vaccines without the need for high doses or demanding particular delivery regimens elicited robust immune responses and afforded completely protective potencies, which indicated the potential of the SFV replicon as vector of anthrax vaccines for use in clinical application. Therefore, our results suggest that these PA-expressing SFV replicon DNA or VRP vaccines may be suitable as candidate vaccines against anthrax. PMID:25102364

Wang, Hai-Chao; An, Huai-Jie; Yu, Yun-Zhou; Xu, Qing

2015-02-01

103

A High Excision Potential of TALENs for Integrated DNA of HIV-Based Lentiviral Vector

DNA-editing technology has made it possible to rewrite genetic information in living cells. Human immunodeficiency virus (HIV) provirus, an integrated form of viral complementary DNA in host chromosomes, could be a potential target for this technology. We recently reported that HIV proviral DNA could be excised from the chromosomal DNA of HIV-based lentiviral DNA-transduced T cells after multiple introductions of a clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 endonuclease system targeting HIV long terminal repeats (LTR). Here, we generated a more efficient strategy that enables the excision of HIV proviral DNA using customized transcription activator-like effector nucleases (TALENs) targeting the same HIV LTR site. A single transfection of TALEN-encoding mRNA, prepared from in vitro transcription, resulted in more than 80% of lentiviral vector DNA being successfully removed from the T cell lines. Furthermore, we developed a lentiviral vector system that takes advantage of the efficient proviral excision with TALENs and permits the simple selection of gene-transduced and excised cells in T cell lines. PMID:25781496

Misawa, Naoko; Sakuma, Tetsushi; Kobayashi, Tomoko; Yamamoto, Takashi; Koyanagi, Yoshio

2015-01-01

104

A potential food-grade cloning vector, pND919, was constructed and transformed into S. thermophilus ST3-1, a plasmid-free strain. The vector contains DNAs from two different food-approved organisms, Streptococcus thermophilus and Lactococcus lactis. The 5.0-kb pND919 is a derivative of the cloning vector pND918 (9.3 kb) and was constructed by deletion of the 4.3-kb region of pND918 which contained DNA from non-food-approved organisms. pND919 carries a heterologous native cadmium resistance se...

Wong, Wing Yee; Su, Ping; Allison, Gwen E.; Liu, Chun-qiang; Dunn, Noel W.

2003-01-01

105

We have analytically studied bound states of the one-dimensional Dirac equation for scalar and vector double square-well potentials (DSPs), by using the transfer-matrix method. Detailed numerical calculations of the eigenvalue, wave function and density probability have been performed for the three cases: (1) vector DSP only, (2) scalar DSP only, and (3) scalar and vector DSPs with equal magnitudes. We discuss the difference and similarity among results of the cases (1)-(3) in the Dirac equation and that in the Schrödinger equation. Motion of a wave packet is calculated for a study on quantum tunneling through the central barrier in the DSP.

Hasegawa, Hideo

2014-05-01

106

International Nuclear Information System (INIS)

Relativistic comparison theorems are established for discrete eigenvalues of Klein–Gordon equation with vector and scalar potentials in d-dimensions. Theorem 1: If V(?) and S(?) depend on a parameter ?, ?S/???0, S?0, ?V/???0, V?0, E>0, then it follows that ?En/???0. Theorem 2: If S2?S1?0, 0?V2?V1, E>0, then the corresponding eigenvalues are ordered as En(2)?En(1). Theorem 3: If 0?V2?V1, S2?|S1|, En(1)>0, En(2)>0, then En(2)?En(1). Some illustrative examples are given. -- Highlights: ? Generalize relativistic comparison theorems to scalar and vector potentials. ? We establish three theorems in different conditions. ? Theorem 1 applies to a family potential which contain a common parameter. ? Theorems 2, 3 are suitable for different two families of scalar and vector potentials.

107

Preliminary analyses for HTTR`s start-up physics tests by Monte Carlo code MVP

Energy Technology Data Exchange (ETDEWEB)

Analyses of start-up physics tests for High Temperature Engineering Test Reactor (HTTR) have been carried out by Monte Carlo code MVP based on continuous energy method. Heterogeneous core structures were modified precisely, such as the fuel compacts, fuel rods, coolant channels, burnable poisons, control rods, control rod insertion holes, reserved shutdown pellet insertion holes, gaps between graphite blocks, etc. Such precise modification of the core structures was difficult with diffusion calculation. From the analytical results, the followings were confirmed; The first criticality will be achieved around 16 fuel columns loaded. The reactivity at the first criticality can be controlled by only one control rod located at the center of the core with other fifteen control rods fully withdrawn. The excess reactivity, reactor shutdown margin and control rod criticality positions have been evaluated. These results were used for planning of the start-up physics tests. This report presents analyses of start-up physics tests for HTTR by MVP code. (author)

Nojiri, Naoki [Science and Technology Agency, Tokyo (Japan); Nakano, Masaaki; Ando, Hiroei; Fujimoto, Nozomu; Takeuchi, Mitsuo; Fujisaki, Shingo; Yamashita, Kiyonobu

1998-08-01

108

Analysis of the HTR-10 initial core with a monte Carlo code MVP

International Nuclear Information System (INIS)

The HTR-10 initial core has been analyzed by using a continuous-energy Monte Carlo code MVP with the nuclear data libraries JENDL-3.3, ENDF/B-6.8 and JEFF-3.0 to ascertain the accuracy of the code and address the bias of the libraries. The MVP statistical geometry model has been improved and employed to treat the heterogeneity of stochastic materials such as randomly distributed pebbles and coated fuel particles. All the keff results agree with the experimental one within the deviation of about 0.8%. To be precise, the JENDL-3.3, ENDF/B-6.8 and JEFF-3.0 results overestimate by about 0.4%, 0.8% and 0.7%, respectively. The impact of nearest neighbor distributions (NNDs) has been also investigated for the kekk values. No significant difference can be seen between the theoretical NNDs and the ones obtained by the MCRDF code. (authors)

109

Validation analysis of burnup code MVP-ORBURN using the SFCOMPO database

International Nuclear Information System (INIS)

A series of burnup calculations was conducted for typical post irradiation experimental data prepared in SFCOMPO using Jones's MVP-ORBURN code, which is a coupling codes of MVP-II and ORIGEN2. The analyzed cases cover a wide range of data including four pressurized water reactors (PWRs) and three boiling water reactors (BWRs). As long as the post-irradiation composition of major actinides applied in the Level 1 burnup credit are concerned, the calculation results of end of cycle (EOC) compositions obtained using the JENDL-3.3 nuclear data library showed a good agreement within a range of 10% discrepancy between the calculations and the experiments. Consequently, the code system is found to be sufficiently applicable to burnup credit evaluations. (authors)

110

Neutronics analysis of Dalat Nuclear Research Reactor by MVP/GMVP code

International Nuclear Information System (INIS)

The paper presents neutronics calculation for Dalat Nuclear Research Reactor (DNRR) to validate MVP/GMVP Code. Beside fresh core calculation, burnt core and burn up distribution were also carried out and compared with experimental data or result obtained from other codes. With complex geometry and operating history like DNRR, burn up calculation by Monte Carlo Method is the better choice owing to the use of exact geometry description and continuous neutron energy in calculation. The discrepancy between calculated data and experimental data is good to compare. By using Monte Carlo method, continuous neutron energy from JENDL3.3 library and combined with burn up calculation, MVP/GMVP Code is a very useful tool for reactor calculation. (author)

111

Using Landau Fermi liquid theory we derive a nonlinear non-adiabatic approximation for the exchange-correlation (xc) vector potential defined by the xc stress tensor. The stress tensor is a local nonlinear functional of two basic variables - the displacement vector and the second-rank tensor which describes the evolution of momentum in a local frame moving with Eulerian velocity. For irrotational motion and equilibrium initial state the dependence on the tensor variable redu...

Tokatly, I. V.; Pankratov, O.

2002-01-01

112

Abstract The aim of the present study was twofold. First, in general, to reveal new aspects of the potential vector role of ixodid ticks and fleas by screening large numbers of specimens with recently developed molecular biological methods. Second, to evaluate the occurrence of vector-borne infectious agents in a geographical context. Altogether 3,442 unfed hard ticks (Ixodes ricinus, Dermacentor marginatus, D. reticulatus, Haemaphysalis inermis, H. concinna, H. punctata) and 939 f...

Hornok, Sa?ndor; Meli, Marina L.; Perreten, Andrea; Farkas, Ro?bert; Willi, Barbara; Beugnet, Frederic; Lutz, Hans; Hofmann-lehmann, Regina

2009-01-01

113

We prescribe a pseudo-Newtonian vector potential for studying accretion disks around Kerr black holes. The potential is useful to study the inner properties of disk not confined to the equatorial plane where general relativistic effect is indispensable. Therefore, we incorporate the essential properties of the metric at the inner radii through the pseudo-Newtonian potential derived from the general Kerr spacetime. The potential, reproducing most of the salient features of th...

Ghosh, Shubhrangshu; Mukhopadhyay, Banibrata

2007-01-01

114

International Nuclear Information System (INIS)

In order to realize fast and accurate Monte Carlo simulation of neutron and photon transport problems, new algorithms have been studied, and two fully vectorized Monte Carlo codes MVP and GMVP have been developed for FACOM VP series vector supercomputers. The former and latter codes use the continuous energy model and the multi-group model, respectively. Compared with conventional scalar codes, these codes achieve higher computation speed by a factor of 10 or more on FACOM VP-2600. Both codes have functions for production use including accurate physics model, geometry description capability and variance reduction technique. In addition to the execution on the vector supercomputers, these codes can be used on vector-parallel supercomputers with parallel calculation capability and on workstations with an OS of UNIX. For the continuous energy method, many nuclear data libraries have been prepared based on mainly JENDL 3. This report describes the physics model, geometry description method used in the codes and how to use them. (author)

115

Zero vector potential mechanism of attosecond absorption in strongly relativistic plasmas

The understanding of the physics of lasermatter interactions in the strongly relativistic regime is of fundamental importance. In this article, a new mechanism of fast electron generation at the vacuum-solid boundary of intense laser pulse interaction with overdense plasma is described. It is one that has no analogue in classical, non-relativistic laser-plasma interactions. Here, conclusive proof is provided that the key contribution to the fast electron generation is given by the zero points of the vector potential. We demonstrate that the new mechanism leads to scalings for the fast electron energy, which explicitly depend on the plasma density, thus providing a new insight into relativistic laser-matter interaction. Furthermore, it is shown that this new mechanism provides the dominant contribution to the interaction by the injection of energy into the overdense plasma delivered by attosecondduration electron bunches. This new understanding will allow the future generation of a single ultra-bright attoseco...

Baeva, T; Robinson, A P L; Norreys, P A

2010-01-01

116

Estimation of action potential of the cellular membrane using support vectors machines.

In this article an application of the support vectors machines (SVM) is presented in the problem of the estimate of the action potential of the cellular membrane V, which is, a temporary function, highly non-linear, of the ionic concentrations of sodium and potassium. A model, for the estimate of V, is the Hodgkin-Huxley (HH) model that describes the dynamics of V similar to an electric circuit with passive elements representing the biochemical variables involved in the process. SVM are algorithms of emergent computation that have demonstrated an excellent performance in classification and regression applications; in this article they are used for the estimate of V and the result is compared with that obtained using HH, demonstrating that SVM are a promising alternative in modelling problem of biological processes. PMID:17946230

Seijas, Cesar; Caralli, Antonino; Villazana, Sergio

2006-01-01

117

Aedes vexans and Culex pipiens as the potential vectors of Dirofilaria immitis in Central Turkey.

This study was carried out to investigate the potential vectors and relative mosquito infection rates of Dirofilaria immitis throughout two mosquito seasons (2008-2009) in Kayseri province where is located in Central Anatolian part of Turkey. For this aim, totally 1198 genomic DNA pools, extracted and grouped according to the species and collection site (1-17 specimens/pool) from 6153 mosquito specimens, were examined by PCR using species-specific primers for D. immitis. The captured mosquitoes from 46 focuses were survived under in vitro conditions for 7 days to allow the development of larval stages of D. immitis. DNA extraction was performed individually to both thorax-head and abdomens in order to determine infective and infected mosquito specimens, respectively. The most abundant mosquito species in the study area was determined as Ae. vexans (51.7%) and this was followed by Cx. pipiens (42.1%), Cx. theileri (3.1%), Cs. annulata (1.5%), An. maculipennis (1.0%) and Cx. hortensis (0.6%). The PCR results indicated that 9/312 and 12/312 pools from Ae. vexans abdomens and thorax-heads were positive for filarial DNAs, respectively where as 3/241 pools of each abdomens and thorax-heads from Cx. pipiens were positive for D. immitis DNAs. The minimum infection rates (MIRs) for Ae. vexans and Cx. pipiens were calculated as 0.41 and 0.12, respectively. Although D. immitis DNA's were found in both pools from Ae. vexans and Cx. pipiens, the calculated MIRs provide evidence that Ae. vexans could be the main potential vector of D. immitis in Kayseri. PMID:21232866

Yildirim, A; Inci, A; Duzlu, O; Biskin, Z; Ica, A; Sahin, I

2011-05-31

118

Benchmark analysis of SPERT-IV reactor with Monte Carlo code MVP

International Nuclear Information System (INIS)

Highlights: • MVP was used for SPERT-IV core modeling. • Neutronics analysis of SPERT-IV reactor was performed. • Calculation performed to estimate critical rod height, excess reactivity. • Neutron flux, time integrated neutron flux and Cd-ratio also calculated. • Calculated values agree with experimental data. - Abstract: The benchmark experiment of the SPERT-IV D-12/25 reactor core has been analyzed with the Monte Carlo code MVP using the cross-section libraries based on JENDL-3.3. The MVP simulation was performed for the clean and cold core. The estimated values of Keff at the experimental critical rod height and the core excess reactivity were within 5% with the experimental data. Thermal neutron flux profiles at different vertical and horizontal positions of the core were also estimated. Cadmium Ratio at different point of the core was also estimated. All estimated results have been compared with the experimental results. Generally good agreement has been found between experimentally determined and the calculated results

119

Neuroprotective potential of a viral vector system induced by a neurological insult

Gene transfer into neurons via viral vectors for protection against acute necrotic insults has generated considerable interest. Most studies have used constitutive vector systems, limiting the ability to control transgene expression in a dose-dependent, time-dependent, or reversible manner. We have constructed defective herpes simplex virus vectors designed to be induced by necrotic neurological insults themselves. Such vectors contain a synthetic glucocorticoid-responsive promoter, taking ad...

Ozawa, Clare R.; Ho, Jill J.; Tsai, David J.; Ho, Dora Y.; Sapolsky, Robert M.

2000-01-01

120

The optical potential for vector-polarized deuterons of 52 MeV

International Nuclear Information System (INIS)

The vector analysing power for elastic scattering of 52 MeV polarized deuterons was measured for 12C, 16O, 20Ne, 28Si, 32S, 40Ar, 58Ni, 90Zr and 197Au. The data were analysed together with previously measured differential cross sections in the framework of the optical model. Best-fit and average optical-model parameters were obtained both for surface and volume absorption. Fits with surface absorption are superior to those with volume absorption, especially for heavier nuclei. Typical parameters of the spin-orbit part of the best-fit optical potentials are found to be Vsub(s.o) approx. equal to 5.5 MeV, rsub(s.o) approx. equal to 1.15 fm and ?sub(s.o) approx. equal to 0.4 fm, and there is no evidence for an imaginary component. The volume integrals and rms radii of real, imaginary and l x s potentials show a smooth mass dependence and differ insignificantly for different sets of potentials. (orig.)

121

The present study focuses on the electric field features and related physical properties which can be derived from the topology of the experimental electrostatic potential. These properties were retrieved from the electron density multipole refinement of high-resolution x-ray data collected on a racemic crystal of ibuprofen drug. The electric field lines are depicted around the molecule revealing gradient vector zero flux atomic basins and critical points (CP's) having a different significance than that brought out by the topology of the electron density. This method emphasizes a partioning of the molecular system mainly governed by the nuclear-electron interaction. The concept of Slater's nuclear screening is here explored from the inspection of the gradient field zero flux surface separating the atoms in the molecule. Moreover, empirical parameters like covalent or atomic bond radii are accurately estimated from CP-atom distances in the molecular heteroatomic bonds. The local minima of the electrostatic potential are searched around the ibuprofen molecule in order to locate the binding sites for further molecular interactions with biological targets or with excipients in pharmaceutical preparations. Ibuprofen dipole moment is also estimated by a method based upon the fit to the experimental electrostatic potential values generated around the molecule.

Bouhmaida, Nouzha; Dutheil, Michael; Ghermani, Nour Eddine; Becker, Pierre

2002-04-01

122

Live-attenuated rubella vaccine strain RA27/3 has been demonstrated to be safe and immunogenic in millions of children. The vaccine strain was used to insert SIV gag sequences and the resulting rubella vectors were tested in rhesus macaques alone and together with SIV gag DNA in different vaccine prime-boost combinations. We previously reported that such rubella vectors induce robust and durable SIV-specific humoral immune responses in macaques. Here, we report that recombinant rubella vectors elicit robust de novo SIV-specific cellular immune responses detectable for >10 months even after a single vaccination. The antigen-specific responses induced by the rubella vector include central and effector memory CD4(+) and CD8(+) T cells with cytotoxic potential. Rubella vectors can be administered repeatedly even after vaccination with the rubella vaccine strain RA27/3. Vaccine regimens including rubella vector and SIV gag DNA in different prime-boost combinations resulted in robust long-lasting cellular responses with significant increase of cellular responses upon boost. Rubella vectors provide a potent platform for inducing HIV-specific immunity that can be combined with DNA in a prime-boost regimen to elicit durable cellular immunity. PMID:25802183

Rosati, Margherita; Alicea, Candido; Kulkarni, Viraj; Virnik, Konstantin; Hockenbury, Max; Sardesai, Niranjan Y; Pavlakis, George N; Valentin, Antonio; Berkower, Ira; Felber, Barbara K

2015-04-27

123

The Nature of the Vector and Scalar Potentials and Gauge Invariance in the Context of Gauge Theory

Modern undergraduate textbooks in electricity and magnetism typically focus on a force representation of electrodynamics with an emphasis on Maxwell's Equations and the Lorentz Force Law. The vector potential $\\mathbf{A}$ and scalar potential $\\Phi$ play a secondary role mainly as quantities used to calculate the electric and magnetic fields. However, quantum mechanics including quantum electrodynamics (QED) and other gauge theories demands a potential ($\\Phi$,$\\mathbf{A}$) ...

Stein, T.

2007-01-01

124

We present some numerical methods for the semiclassical Schrodinger equation in which the wave function propagates O(epsilon) oscillations in space and time where epsilon denotes the rescaled Planck constant. The first two methods are concerned with semi-classical Schrodinger equations with vector potentials. The first method is the semi-Lagrangian time-splitting method. By operator splitting, the equation is divided into the kinetic step, the convection step and the potential step. For the convection step, we propose a semi-Lagrangian method in order to allow large time steps. We prove the unconditional stability conditions with spatially variant external vector potentials, and the error estimate in the l2 approximation of the wave function. By comparing with the semi-classical limit, we show that this method is able to capture the correct physical observables with time step Deltat >> epsilon. The second method is the Hagedorn wave packets (abbreviated by HWP) approach, where the Hamiltonian is divided into the modified part and the residual part. The modified Hamiltonian which determines the HWP dynamics, is chosen so that a crucial correction term is added to the truncated Hamiltonian. The residual part is treated by a Galerkin approximation. We prove that, with the modified Hamiltonian only, the HWP's dynamics gives the asymptotic solution with error O(epsilon1/2). We also prove that, the Galerkin approximation for the residual Hamiltonian can reduce the approximation error to O(epsilonk/2), where k depends on the number of HWP's added to the dynamics. Besides, the semi-classical limits of the TDSCF equations are studied in the framework of Wigner transforms. In the mixed quantum classical limit, the limiting equation agrees with the Ehrenfest method, and in the classical limit, the limiting equations are the coupled Liouville equations. These results are for the first time derived by the Wigner measure techniques. The corresponding numerical methods we present can capture the correct physical observables with delta-epsilon-independent time steps, where delta and epsilon are dimensionless semi-classical parameters. Also, we have provided a way to design a second order (in time) or even higher order methods to solve the both TDSCF equations and the Ehrenfest equations.

Zhou, Zhennan

125

A 2-year entomological study of potential malaria vectors in central Italy.

Europe was officially declared free from malaria in 1975; nevertheless, this disease remains a potential problem related to the presence of former vectors, belonging to the Anopheles maculipennis complex. Autochthonous-introduced malaria cases, recently reported in European countries, together with the predicted climatic and environmental changes, have increased the concern of health authorities over the possible resurgence of this disease in the Mediterranean Basin. In Italy, to study the distribution and bionomics of indigenous anopheline populations and to assess environmental parameters that could influence their dynamics, an entomological study was carried out in 2005-2006 in an at-risk study area. This model area is represented by the geographical region named the Maremma, a Tyrrhenian costal plain in Central Italy, where malaria was hyperendemic up to the 1950s. Fortnightly, entomological surveys (April-October) were carried out in four selected sites with different ecological features. Morphological and molecular characterization, blood meal identification, and parity rate assessment of the anophelines were performed. In total, 8274 mosquitoes were collected, 7691 of which were anophelines. Six Anopheles species were recorded, the most abundant of which were Anopheles labranchiae and An. maculipennis s.s. An. labranchiae is predominant in the coastal plain, where it is present in scattered foci. However, this species exhibits a wider than expected range: in fact it has been recorded, for the first time, inland where An. maculipennis s.s. is the most abundant species. Both species fed on a wide range of animal hosts, also showing a marked aggressiveness on humans, when available. Our findings demonstrated the high receptivity of the Maremma area, where the former malaria vector, An. labranchiae, occurs at different densities related to the kind of environment, climatic parameters, and anthropic activities. PMID:19485768

Di Luca, Marco; Boccolini, Daniela; Severini, Francesco; Toma, Luciano; Barbieri, Francesca Mancini; Massa, Antonio; Romi, Roberto

2009-12-01

126

International Nuclear Information System (INIS)

Non-invasively reconstructing the transmembrane potentials (TMPs) from body surface potentials (BSPs) constitutes one form of the inverse ECG problem that can be treated as a regression problem with multi-inputs and multi-outputs, and which can be solved using the support vector regression (SVR) method. In developing an effective SVR model, feature extraction is an important task for pre-processing the original input data. This paper proposes the application of principal component analysis (PCA) and kernel principal component analysis (KPCA) to the SVR method for feature extraction. Also, the genetic algorithm and simplex optimization method is invoked to determine the hyper-parameters of the SVR. Based on the realistic heart-torso model, the equivalent double-layer source method is applied to generate the data set for training and testing the SVR model. The experimental results show that the SVR method with feature extraction (PCA-SVR and KPCA-SVR) can perform better than that without the extract feature extraction (single SVR) in terms of the reconstruction of the TMPs on epi- and endocardial surfaces. Moreover, compared with the PCA-SVR, the KPCA-SVR features good approximation and generalization ability when reconstructing the TMPs.

127

Energy Technology Data Exchange (ETDEWEB)

Non-invasively reconstructing the transmembrane potentials (TMPs) from body surface potentials (BSPs) constitutes one form of the inverse ECG problem that can be treated as a regression problem with multi-inputs and multi-outputs, and which can be solved using the support vector regression (SVR) method. In developing an effective SVR model, feature extraction is an important task for pre-processing the original input data. This paper proposes the application of principal component analysis (PCA) and kernel principal component analysis (KPCA) to the SVR method for feature extraction. Also, the genetic algorithm and simplex optimization method is invoked to determine the hyper-parameters of the SVR. Based on the realistic heart-torso model, the equivalent double-layer source method is applied to generate the data set for training and testing the SVR model. The experimental results show that the SVR method with feature extraction (PCA-SVR and KPCA-SVR) can perform better than that without the extract feature extraction (single SVR) in terms of the reconstruction of the TMPs on epi- and endocardial surfaces. Moreover, compared with the PCA-SVR, the KPCA-SVR features good approximation and generalization ability when reconstructing the TMPs.

Jiang Mingfeng; Wang Yaming [College of Electronics and Informatics, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Zhu Lingyan [Dongfang College, Zhejiang University of Finance and Economics, Hangzhou, 310018 (China); Xia Ling; Shou Guofa; Liu Feng [Department of Biomedical Engineering, Zhejiang University, Hangzhou 310027 (China); Crozier, Stuart, E-mail: peterjiang0517@163.com, E-mail: jiang.mingfeng@hotmail.com [School of Information Technology and Electrical Engineering, University of Queensland, St Lucia, Brisbane, Queensland 4072 (Australia)

2011-03-21

128

Non-invasively reconstructing the transmembrane potentials (TMPs) from body surface potentials (BSPs) constitutes one form of the inverse ECG problem that can be treated as a regression problem with multi-inputs and multi-outputs, and which can be solved using the support vector regression (SVR) method. In developing an effective SVR model, feature extraction is an important task for pre-processing the original input data. This paper proposes the application of principal component analysis (PCA) and kernel principal component analysis (KPCA) to the SVR method for feature extraction. Also, the genetic algorithm and simplex optimization method is invoked to determine the hyper-parameters of the SVR. Based on the realistic heart-torso model, the equivalent double-layer source method is applied to generate the data set for training and testing the SVR model. The experimental results show that the SVR method with feature extraction (PCA-SVR and KPCA-SVR) can perform better than that without the extract feature extraction (single SVR) in terms of the reconstruction of the TMPs on epi- and endocardial surfaces. Moreover, compared with the PCA-SVR, the KPCA-SVR features good approximation and generalization ability when reconstructing the TMPs.

Jiang, Mingfeng; Zhu, Lingyan; Wang, Yaming; Xia, Ling; Shou, Guofa; Liu, Feng; Crozier, Stuart

2011-03-01

129

Polyethylenimine (PEI) functionalized magnetic nanoparticles were synthesized as a potential non-viral vector for gene delivery. The nanoparticles could provide the magnetic-targeting, and the cationic polymer PEI could condense DNA and avoid in vitro barriers. The magnetic nanoparticles were characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, dynamic light scattering measurements, transmission electron microscopy, vibrating sample magnetometer and atomic force microscopy. Agarose gel electrophoresis was used to asses DNA binding and perform a DNase I protection assay. The Alamar blue assay was used to evaluate negative effects on the metabolic activity of cells incubated with PEI modified magnetic nanoparticles and their complexes with DNA both in the presence or absence of an external magnetic field. Flow cytometry and fluorescent microscopy were also performed to investigate the transfection efficiency of the DNA-loaded magnetic nanoparticles in A549 and B16-F10 tumor cells with (+M) or without (-M) the magnetic field. The in vitro transfection efficiency of magnetic nanoparticles was improved obviously in a permanent magnetic field. Therefore, the magnetic nanoparticles show considerable potential as nanocarriers for gene delivery. PMID:22826003

Zhou, Yangbo; Tang, Zhaomin; Shi, Chunli; Shi, Shuai; Qian, Zhiyong; Zhou, Shaobing

2012-11-01

130

An Attenuated Coxsackievirus B3 Vector: A Potential Tool for Viral Tracking Study and Gene Delivery

Cardiomyocytes are quite resistant to gene transfer using standard techniques. We developed an expression vector carrying an attenuated but infectious and replicative coxsackievirus B3 (CVB3) genome, and unique ClaI-StuI cloning sites for an exogenous gene, whose product can be released from the nascent viral polyprotein by 2Apro cleavage. This vector was tested as an expression vehicle for green fluorescent protein (GFP). The vector transiently expressed GFP in cell cultures for at least ten...

Zeng, Jun; Chen, Xiao Xuan; Dai, Jian Ping; Zhao, Xiang Feng; Xin, Gang; Su, Yun; Wang, Ge Fei; Li, Rui; Yan, Yin Xia; Su, Jing Hua; Deng, Yu Xue; Li, Kang Sheng

2013-01-01

131

International Nuclear Information System (INIS)

We present the bound-state solutions to the Klein—Gordon equation with equal scalar and vector modified Hylleraas plus exponential Rosen Morse potentials using the parametric Nikiforov—Uvarov method. We use the elegant approximation scheme to the centrifugal term. The bound state energy eigenvalues and the corresponding wave function are obtained. We also discuss the special cases. (general)

132

The problem of spin-0 and spin-1 bosons subject to a general mixing of minimal and nonminimal vector cusp potentials is explored in a unified way in the context of the Duffin-Kemmer-Petiau theory. Effects on the bound-state solutions due to a short-range interaction are discussed in some detail.

Castro, A. S.

2010-01-01

133

We show that fermion charge fractionalization can take place in a recently proposed chiral gauge model for graphene even in the absence of Kekul\\'e distortion of the graphene honeycomb lattice. We extend the model by adding the coupling of fermions to an external magnetic field and show that the fermion charge can be fractionalized by means of only gauge potentials. It is shown that the chiral fermion charge can also have fractional value. We also relate the fractionalizatio...

Obispo, Angel E.; Hott, Marcelo

2012-01-01

134

International Nuclear Information System (INIS)

Many people these days employ only commercial finite element method (FEM) software when solving for the hysteresis losses of superconductors. Thus, the knowledge of a modeller is in the capability of using the black boxes of software efficiently. This has led to a relatively superficial examination of different formulations while the discussion stays mainly on the usage of the user interfaces of these programs. Also, if we stay only at the mercy of commercial software producers, we end up having less and less knowledge on the details of solvers. Then, it becomes more and more difficult to conceptually solve new kinds of problem. This may prevent us finding new kinds of method to solve old problems more efficiently, or finding a solution for a problem that was considered almost impossible earlier. In our earlier research, we presented the background of a co-tree gauged T-? FEM solver for computing the hysteresis losses of superconductors. In this paper, we examine the feasibility of FEM and eddy current vector potential formulation in the same problem.

135

Waterfowl (Anseriformes) and shorebirds (Charadriiformes) are the most common wild vectors of influenza A viruses. Due to their migratory behavior, some may transmit disease over long distances. Migratory connectivity studies can link breeding and nonbreeding grounds while illustrating potential interactions among populations that may spread diseases. We investigated Dunlin (Calidris alpina), a shorebird with a subspecies (C. a. arcticola) that migrates from nonbreeding areas endemic to avian influenza in eastern Asia to breeding grounds in northern Alaska. Using microsatellites and mitochondrial DNA, we illustrate genetic structure among six subspecies: C. a. arcticola,C. a. pacifica,C. a. hudsonia,C. a. sakhalina,C. a. kistchinski, and C. a. actites. We demonstrate that mitochondrial DNA can help distinguish C. a. arcticola on the Asian nonbreeding grounds with >70% accuracy depending on their relative abundance, indicating that genetics can help determine whether C. a. arcticola occurs where they may be exposed to highly pathogenic avian influenza (HPAI) during outbreaks. Our data reveal asymmetric intercontinental gene flow, with some C. a. arcticola short-stopping migration to breed with C. a. pacifica in western Alaska. Because C. a. pacifica migrates along the Pacific Coast of North America, interactions between these subspecies and other taxa provide route for transmission of HPAI into other parts of North America. PMID:25685191

Miller, Mark P; Haig, Susan M; Mullins, Thomas D; Ruan, Luzhang; Casler, Bruce; Dondua, Alexei; Gates, H River; Johnson, J Matthew; Kendall, Steve; Tomkovich, Pavel S; Tracy, Diane; Valchuk, Olga P; Lanctot, Richard B

2015-02-01

136

Waterfowl (Anseriformes) and shorebirds (Charadriiformes) are the most common wild vectors of influenza A viruses. Due to their migratory behavior, some may transmit disease over long distances. Migratory connectivity studies can link breeding and nonbreeding grounds while illustrating potential interactions among populations that may spread diseases. We investigated Dunlin (Calidris alpina), a shorebird with a subspecies (C. a. arcticola) that migrates from nonbreeding areas endemic to avian influenza in eastern Asia to breeding grounds in northern Alaska. Using microsatellites and mitochondrial DNA, we illustrate genetic structure among six subspecies: C. a. arcticola,C. a. pacifica, C. a. hudsonia, C. a. sakhalina, C. a. kistchinski, and C. a. actites. We demonstrate that mitochondrial DNA can help distinguish C. a. arcticola on the Asian nonbreeding grounds with >70% accuracy depending on their relative abundance, indicating that genetics can help determine whether C. a. arcticola occurs where they may be exposed to highly pathogenic avian influenza (HPAI) during outbreaks. Our data reveal asymmetric intercontinental gene flow, with some C. a. arcticola short-stopping migration to breed withC. a. pacifica in western Alaska. Because C. a. pacifica migrates along the Pacific Coast of North America, interactions between these subspecies and other taxa provide route for transmission of HPAI into other parts of North America.

Miller, Mark P.; Haig, Susan M.; Mullins, Thomas D.; Ruan, Luzhang; Casler, Bruce; Dondua, Alexei; Gates, River H.; Johnson, J. Matthew; Kendall, Steve J.; Tomkovich, Pavel S.; Tracy, Diane; Valchuk, Olga P.; Lanctot, Richard B.

2015-01-01

137

The groundhog tick Ixodes cookei (Acari: ixodidae): a poor potential vector of Lyme borreliosis.

Evidence for infection with the spirochete, Borrelia burgdorferi, was sought in Ixodes cookei and in groundhogs (Marmota monax) in southern Ontario, Canada, and ticks fed on experimentally inoculated hosts were examined for the spirochete. Borrelia burgdorferi was not detected by immunofluorescent examination of 110 larval, nymphal or adult I. cookei collected from the environment, or taken from humans and other animals. Three groundhogs inoculated with B. burgdorferi developed titers of 1:20 to 1:80 by the indirect immunofluorescent antibody test, but B. burgdorferi was not isolated from the spleens, kidneys, or urinary bladders of these animals. One of 30 wild groundhogs had an antibody titer of 1:20 to B. burgdorferi. Three (5%) of 59 I. cookei larvae fed on B. burgdorferi-infected hamsters became infected, in comparison with 23 (28%) of 82 I. dammini larvae fed on the same hosts. Borrelia burgdorferi was present in 5%, 16% and 4% of molted I. cookei nymphs fed on infected hamsters, rats or a groundhog, respectively; prevalences of infection in I. dammini fed on the same hosts were significantly (P Ixodes cookei seems to be an inefficient vector of B. burgdorferi, and is unlikely to be significant in nature. Groundhogs are potential wildlife reservoirs of B. burgdorferi, based on their capacity to transmit infection to I. dammini. PMID:8355343

Barker, I K; Lindsay, L R; Campbell, G D; Surgeoner, G A; McEwen, S A

1993-07-01

138

Using Landau Fermi liquid theory we derive a nonlinear non-adiabatic approximation for the exchange-correlation (xc) vector potential defined by the xc stress tensor. The stress tensor is a local nonlinear functional of two basic variables - the displacement vector and the second-rank tensor which describes the evolution of momentum in a local frame moving with Eulerian velocity. For irrotational motion and equilibrium initial state the dependence on the tensor variable reduces to that on a metrics generated by a dynamical deformation of the system.

Tokatly, I V

2003-01-01

139

A vectorization of the Hess McDonnell Douglas potential flow program NUED for the STAR-100 computer

The computer program NUED for analyzing potential flow about arbitrary three dimensional lifting bodies using the panel method was modified to use vector operations and run on the STAR-100 computer. A high speed of computation and ability to approximate the body surface with a large number of panels are characteristics of NUEDV. The new program shows that vector operations can be readily implemented in programs of this type to increase the computational speed on the STAR-100 computer. The virtual memory architecture of the STAR-100 facilitates the use of large numbers of panels to approximate the body surface.

Boney, L. R.; Smith, R. E., Jr.

1979-01-01

140

S-wave baryons in an equally mixed scalar-vector square root potential model of independent quarks

International Nuclear Information System (INIS)

A relativistic model of independent quarks based on Dirac equation with an equally mixed scalar-vector square root confining potential is used to compute the quark core contributions to the static properties like magnetic moments, charge radii and axial vector coupling constant ratios of the baryon octet. The results obtained with appropriate corrections due to centre-of-mass motion agree fairly well with experimental values. The model is also extended to the study of magnetic moments of the quark core of baryons in the charmed and b-flavoured sectors and the overall predictions so obtained compare well with other model predictions. (author). 71 refs., 6 tabs

141

Postoperative adjuvant MVP Chemotherapy and Radiotherapy for Non-Small Cell Lung Cancer

International Nuclear Information System (INIS)

Purpose : Since February 1991, a prospective study for non-small cell lung cancer patients who underwent radical resection and had a risk factor of positive resection margin or regional lymph node metastasis has been conducted to evaluated the effect of MVP chemotherapy and radiotherapy on the pattern of failure, disease free and overall survival, and tolerance of combined treatment. Materials and Methods : Twenty nine patients were registered to this study until Sep. 1993 ; of these 26 received planned therapy. Within 3 weeks after radical resection, two cycles of MVP(Motomycin C 6 mg/m2 , Vinblastin 6 mg/m2 , Cisplatin 6 mg/m2 ) chemotherapy was given with 4 weeks intervals. Radiotherapy (5040 cGy tumor bed dose and 900 cGy boost to high risk area) was started 3 to 4 weeks after chemotherapy. Results : One and two year overall survival rates were 76.5% and 8.6% respectively. Locoregional failure developed in 6 patients (23.1%) and distant failure in 9 patients(34.6%). Number of involved lymph nodes, resection margin positivity showed some correlation with failure pattern but T-stage and N-stage showed no statistical significance. The group of patients who received chemotherapy within 2 weeks postoperatively and radiotherapy within 70 days showed lower incidence of distant metastasis. Postoperative combined therapy were well tolerated without definite increase of complication rate, and compliance rate in this study was 90%. Conclusionnce rate in this study was 90%. Conclusion : 1) MVP chemotherapy showed no effect on locoregional recurrence, ut appeared to decrease the distant metastasis rate and 2) combined treatments were well tolerated in all patients. 3) The group of patients who received chemotherapy within 2 weeks postoperatively and radiotherapy within 70 days showed lower incidence of distant metastasis. 4) Addition of chemotherapy to radiotherapy failed to increase the overall or disease free survival

142

Postoperative adjuvant MVP Chemotherapy and Radiotherapy for Non-Small Cell Lung Cancer

Energy Technology Data Exchange (ETDEWEB)

Purpose : Since February 1991, a prospective study for non-small cell lung cancer patients who underwent radical resection and had a risk factor of positive resection margin or regional lymph node metastasis has been conducted to evaluated the effect of MVP chemotherapy and radiotherapy on the pattern of failure, disease free and overall survival, and tolerance of combined treatment. Materials and Methods : Twenty nine patients were registered to this study until Sep. 1993 ; of these 26 received planned therapy. Within 3 weeks after radical resection, two cycles of MVP(Motomycin C 6 mg/m{sup 2} , Vinblastin 6 mg/m{sup 2} , Cisplatin 6 mg/m{sup 2} ) chemotherapy was given with 4 weeks intervals. Radiotherapy (5040 cGy tumor bed dose and 900 cGy boost to high risk area) was started 3 to 4 weeks after chemotherapy. Results : One and two year overall survival rates were 76.5% and 8.6% respectively. Locoregional failure developed in 6 patients (23.1%) and distant failure in 9 patients(34.6%). Number of involved lymph nodes, resection margin positivity showed some correlation with failure pattern but T-stage and N-stage showed no statistical significance. The group of patients who received chemotherapy within 2 weeks postoperatively and radiotherapy within 70 days showed lower incidence of distant metastasis. Postoperative combined therapy were well tolerated without definite increase of complication rate, and compliance rate in this study was 90%. Conclusion : 1) MVP chemotherapy showed no effect on locoregional recurrence, ut appeared to decrease the distant metastasis rate and 2) combined treatments were well tolerated in all patients. 3) The group of patients who received chemotherapy within 2 weeks postoperatively and radiotherapy within 70 days showed lower incidence of distant metastasis. 4) Addition of chemotherapy to radiotherapy failed to increase the overall or disease free survival.

Kim, Jong Hoon; Choi, Eun Kyung; Chang, Hye Sook [Ulsan University College of Medicine, Seoul (Korea, Republic of)] (and others)

1995-06-15

143

The aim of the present study was twofold. First, in general, to reveal new aspects of the potential vector role of ixodid ticks and fleas by screening large numbers of specimens with recently developed molecular biological methods. Second, to evaluate the occurrence of vector-borne infectious agents in a geographical context. Altogether 3442 unfed hard ticks (Ixodes ricinus, Dermacentor marginatus, D. reticulatus, Haemaphysalis inermis, H. concinna, H. punctata) and 939 fleas of cats and dogs (Ctenocephalides felis, C. canis, Pulex irritans) were collected in Hungary. DNA was extracted and analyzed in pools for representatives of the orders Rickettsiales and Mycoplasmatales. H. inermis was newly identified as the most important potential vector for Rickettsia helvetica in the study region. A novel Rickettsia genotype (designated 'Candidatus R. hungarica') was also detected in the same tick species, with a maximum of 95.8% gltA gene sequence identity to known rickettsiae. In addition, P. irritans tested positive for Rickettsia sp. RF2125, which has not been previously described in Europe. The human pathogen R. felis and the feline pathogen 'Candidatus Mycoplasma turicensis' were shown for the first time to occur in Central-Eastern Europe. Further novel findings include the presence of Spiroplasma spp. in D. marginatus and fleas. In conclusion, this molecular study extends the geographic range and vector spectrum of several arthropod-borne agents, some of which have zoonotic potential. PMID:19660880

Hornok, Sándor; Meli, Marina L; Perreten, Andrea; Farkas, Róbert; Willi, Barbara; Beugnet, Frederic; Lutz, Hans; Hofmann-Lehmann, Regina

2010-01-01

144

Analysis of TCA critical experiment with PWR-type MOX fuel by using Monte Carlo code MVP

International Nuclear Information System (INIS)

Two-region TCA critical experiments with six kinds of PWR-type MOX fuel cores were analyzed by using Monte Carlo code MVP. MVP calculated the effective multiplication factors, Keff, of critical cores reproduce the experimental values within an error of 0.3%. The relative power distributions (MOX region) of five kinds of cores reproduce the experimental values within an error of 3%. The experimental values of epithermal flux distribution in cores are reproduced within an error of 6% by MVP calculations. ENDL-3.2 and JENDL-3.3 were used as the core data library. The experimental system, parameters of cores, arrangement of fuel rods, measurement results and comparison of calculated values and experimental values are stated. (S.Y.)

145

Analysis of high moderation PWR MOX core MISTRAL-4 with SRAC and MVP

Energy Technology Data Exchange (ETDEWEB)

An extensive experimental program, MISTRAL, is undertaken by NUPEC and CEA in order to measure the main core physics parameters of high moderation 100% MOX LWRs. The analysis of the MISTRAL-4, a mock-up of a full MOX PWR core was carried out by diffusion/transport calculations with the SRAC code system and by continuous-energy Monte Carlo calculations with the MVP code. The calculation results agreed with the experimental results of both calculations within experimental uncertainties and calculation results showed no specific trend caused by heterogeneity in highly-moderated mock-up core configurations. (author)

Tatsumi, Masahiro [Nuclear Fuel Industries, Ltd., Fuel Engineering and Development Department, Kumatori, Osaka (Japan); Kan, Taro [Mitsubishi Heavy Industries, Ltd., Nuclear Energy Systems Engineering Center, Yokohama, Kanagawa (Japan); Ishii, Kazuya [Hitachi, Ltd., Power and Industrial Systems R and D Lab., Hitachi, Ibaraki (Japan); Ando, Yoshihira [Toshiba Corp., Power and Industrial Systems Research and Development Center, Kawasaki, Kanagawa (Japan); Yamamoto, Toru; Iwata, Yutaka; Ueji, Masao [Nuclear Power Engineering Corp., Systems Safety Department, Tokyo (Japan)

2002-08-01

146

International Nuclear Information System (INIS)

Full text: The calculation of initial core criticality of Thai Research Reactor-1/Modification 1 was performed by the continuous energy Monte Carlo Code MVP and the material cross-sections from JENDL-3.3 continuous-energy library. After that gemstone irradiation facility model were extended for calculation on the magnitude of the reactivity loss. The results showed that total reactivity worth of the control system was 10.83. The reactivity effects associated with the insertion of gemstone irradiation facility was about -0.43% ?k/k

147

Analysis of high moderation PWR MOX core MISTRAL-4 with SRAC and MVP

International Nuclear Information System (INIS)

An extensive experimental program, MISTRAL, is undertaken by NUPEC and CEA in order to measure the main core physics parameters of high moderation 100% MOX LWRs. The analysis of the MISTRAL-4, a mock-up of a full MOX PWR core was carried out by diffusion/transport calculations with the SRAC code system and by continuous-energy Monte Carlo calculations with the MVP code. The calculation results agreed with the experimental results of both calculations within experimental uncertainties and calculation results showed no specific trend caused by heterogeneity in highly-moderated mock-up core configurations. (author)

148

Aedes hensilli as a Potential Vector of Chikungunya and Zika Viruses

An epidemic of Zika virus (ZIKV) illness that occurred in July 2007 on Yap Island in the Federated States of Micronesia prompted entomological studies to identify both the primary vector(s) involved in transmission and the ecological parameters contributing to the outbreak. Larval and pupal surveys were performed to identify the major containers serving as oviposition habitat for the likely vector(s). Adult mosquitoes were also collected by backpack aspiration, light trap, and gravid traps at select sites around the capital city. The predominant species found on the island was Aedes (Stegomyia) hensilli. No virus isolates were obtained from the adult field material collected, nor did any of the immature mosquitoes that were allowed to emerge to adulthood contain viable virus or nucleic acid. Therefore, laboratory studies of the probable vector, Ae. hensilli, were undertaken to determine the likelihood of this species serving as a vector for Zika virus and other arboviruses. Infection rates of up to 86%, 62%, and 20% and dissemination rates of 23%, 80%, and 17% for Zika, chikungunya, and dengue-2 viruses respectively, were found supporting the possibility that this species served as a vector during the Zika outbreak and that it could play a role in transmitting other medically important arboviruses. PMID:25299181

Ledermann, Jeremy P.; Guillaumot, Laurent; Yug, Lawrence; Saweyog, Steven C.; Tided, Mary; Machieng, Paul; Pretrick, Moses; Marfel, Maria; Griggs, Anne; Bel, Martin; Duffy, Mark R.; Hancock, W. Thane; Ho-Chen, Tai; Powers, Ann M.

2014-01-01

149

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Objective To explore the role of Major Vault Protein (MVP in oral cavity squamous cell carcinoma patients. Subjects and Methods 131 consecutive patients suffering from oral cavity squamous cell carcinoma were included in the study. In the whole series, the mean follow-up for survivors was 123.11?±?40.36?months. Patients in tumour stages I and II were referred to surgery; patients in stage III-IV to postoperative radiotherapy (mean dose?=?62.13?±?7.74?Gy in 1.8–2?Gy/fraction. MVP expression was studied by immunohistochemistry in paraffin-embedded tumour tissue. Results MVP expression was positive in 112 patients (85.5% and no relation was found with clinic pathological variables. MVP overexpression (those tumours with moderate or strong expression of the protein was related to insulin-like growth factor receptor-1 (IGF-1R expression (P?=?0.014. Tumour stage of the disease was the most important prognostic factor related to survival. Tumours overexpressing MVP and IGF-1R were strongly related to poor disease-free survival (P?=?0.008, Exp(B?=?2.730, CI95% (1.302-5.724 and cause-specific survival (P?=?0.014, Exp(B?=?2.570, CI95% (1.215-5.437 in patients achieving tumour stages III-IV, in multivariate analysis. Conclusions MVP and IGF-1R expression were related in oral squamous cell carcinoma and conferred reduced long-term survival in patients suffering from advanced stages of the disease.

Henríquez-Hernández Luis

2012-08-01

150

An attenuated coxsackievirus b3 vector: a potential tool for viral tracking study and gene delivery.

Cardiomyocytes are quite resistant to gene transfer using standard techniques. We developed an expression vector carrying an attenuated but infectious and replicative coxsackievirus B3 (CVB3) genome, and unique ClaI-StuI cloning sites for an exogenous gene, whose product can be released from the nascent viral polyprotein by 2A(pro) cleavage. This vector was tested as an expression vehicle for green fluorescent protein (GFP). The vector transiently expressed GFP in cell cultures for at least ten passages and delivered functional GFP to the infected cardiomyocytes for at least 6 days. Moreover, the recombinant viruses showed virulence attenuation in vitro and in vivo. The findings suggest that the recombinant CVB3 vector could be a useful tool for viral tracking study and delivering exogenous proteins to cardiomyocytes. PMID:24386270

Zeng, Jun; Chen, Xiao xuan; Dai, Jian ping; Zhao, Xiang feng; Xin, Gang; Su, Yun; Wang, Ge fei; Li, Rui; Yan, Yin xia; Su, Jing hua; Deng, Yu xue; Li, Kang sheng

2013-01-01

151

Abstract Background Malaria is rampant in Africa and causes untold mortality and morbidity. Vector-borne diseases are climate sensitive and this has raised considerable concern over the implications of climate change on future disease risk. The problem of malaria vectors (Anopheles mosquitoes) shifting from their traditional locations to invade new zones is an important concern. The vision of this study was to exploit the sets of information previously generated by entomologists, e.g. on geog...

Ym, Kangalawe Richard; Ez, Tonnang Henri; Yanda Pius Z

2010-01-01

152

Genetic specificity and potential for local adaptation between dengue viruses and mosquito vectors

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Several observations support the hypothesis that vector-driven selection plays an important role in shaping dengue virus (DENV genetic diversity. Clustering of DENV genetic diversity at a particular location may reflect underlying genetic structure of vector populations, which combined with specific vector genotype × virus genotype (G × G interactions may promote adaptation of viral lineages to local mosquito vector genotypes. Although spatial structure of vector polymorphism at neutral genetic loci is well-documented, existence of G × G interactions between mosquito and virus genotypes has not been formally demonstrated in natural populations. Here we measure G × G interactions in a system representative of a natural situation in Thailand by challenging three isofemale families from field-derived Aedes aegypti with three contemporaneous low-passage isolates of DENV-1. Results Among indices of vector competence examined, the proportion of mosquitoes with a midgut infection, viral RNA concentration in the body, and quantity of virus disseminated to the head/legs (but not the proportion of infected mosquitoes with a disseminated infection strongly depended on the specific combinations of isofemale families and viral isolates, demonstrating significant G × G interactions. Conclusion Evidence for genetic specificity of interactions in our simple experimental design indicates that vector competence of Ae. aegypti for DENV is likely governed to a large extent by G × G interactions in genetically diverse, natural populations. This result challenges the general relevance of conclusions from laboratory systems that consist of a single combination of mosquito and DENV genotypes. Combined with earlier evidence for fine-scale genetic structure of natural Ae. aegypti populations, our finding indicates that the necessary conditions for local DENV adaptation to mosquito vectors are met.

Richardson Jason H

2009-07-01

153

Potential effects of warmer worms and vectors on onchocerciasis transmission in West Africa.

Development times of eggs, larvae and pupae of vectors of onchocerciasis (Simulium spp.) and of Onchocerca volvulus larvae within the adult females of the vectors decrease with increasing temperature. At and above 25°C, the parasite could reach its infective stage in less than 7 days when vectors could transmit after only two gonotrophic cycles. After incorporating exponential functions for vector development into a novel blackfly population model, it was predicted that fly numbers in Liberia and Ghana would peak at air temperatures of 29°C and 34°C, about 3°C and 7°C above current monthly averages, respectively; parous rates of forest flies (Liberia) would peak at 29°C and of savannah flies (Ghana) at 30°C. Small temperature increases (less than 2°C) might lead to changes in geographical distributions of different vector taxa. When the new model was linked to an existing framework for the population dynamics of onchocerciasis in humans and vectors, transmission rates and worm loads were projected to increase with temperature to at least 33°C. By contrast, analyses of field data on forest flies in Liberia and savannah flies in Ghana, in relation to regional climate change predictions, suggested, on the basis of simple regressions, that 13-41% decreases in fly numbers would be expected between the present and before 2040. Further research is needed to reconcile these conflicting conclusions. PMID:25688018

Cheke, Robert A; Basáñez, Maria-Gloria; Perry, Malorie; White, Michael T; Garms, Rolf; Obuobie, Emmanuel; Lamberton, Poppy H L; Young, Stephen; Osei-Atweneboana, Mike Y; Intsiful, Joseph; Shen, Mingwang; Boakye, Daniel A; Wilson, Michael D

2015-04-01

154

Potential effects of warmer worms and vectors on onchocerciasis transmission in West Africa

Development times of eggs, larvae and pupae of vectors of onchocerciasis (Simulium spp.) and of Onchocerca volvulus larvae within the adult females of the vectors decrease with increasing temperature. At and above 25°C, the parasite could reach its infective stage in less than 7 days when vectors could transmit after only two gonotrophic cycles. After incorporating exponential functions for vector development into a novel blackfly population model, it was predicted that fly numbers in Liberia and Ghana would peak at air temperatures of 29°C and 34°C, about 3°C and 7°C above current monthly averages, respectively; parous rates of forest flies (Liberia) would peak at 29°C and of savannah flies (Ghana) at 30°C. Small temperature increases (less than 2°C) might lead to changes in geographical distributions of different vector taxa. When the new model was linked to an existing framework for the population dynamics of onchocerciasis in humans and vectors, transmission rates and worm loads were projected to increase with temperature to at least 33°C. By contrast, analyses of field data on forest flies in Liberia and savannah flies in Ghana, in relation to regional climate change predictions, suggested, on the basis of simple regressions, that 13–41% decreases in fly numbers would be expected between the present and before 2040. Further research is needed to reconcile these conflicting conclusions. PMID:25688018

Cheke, Robert A.; Basáñez, Maria-Gloria; Perry, Malorie; White, Michael T.; Garms, Rolf; Obuobie, Emmanuel; Lamberton, Poppy H. L.; Young, Stephen; Osei-Atweneboana, Mike Y.; Intsiful, Joseph; Shen, Mingwang; Boakye, Daniel A.; Wilson, Michael D.

2015-01-01

155

Analysis of High-Moderation MOX Core MISTRAL-3 with SRAC and MVP

Energy Technology Data Exchange (ETDEWEB)

To obtain reactor physics parameters for high-moderation mixed-oxide (MOX) cores, Nuclear Power Engineering Corporation (NPEC), the French Atomic Commission (CEA), and their industrial partners have conducted a MOX core physics experimental program called MISTRAL with the EOLE critical facility of the Cadarache research center. This program consists of four high-moderation cores and was successfully completed in July 2000. This paper describes the analysis results of MISTRAL-3 that is a homogeneous full MOX cylindrical core (H/HM = 6.2) with an 80-cm height and a 59-cm diameter consisting of 1388 standard pressurized water reactor-type MOX fuel rods of 7.0 wt% plutonium-enrichment in a square pitch of 1.39 cm. NPEC has been analyzing the experimental results by using the SRAC and MVP code systems. SRAC and MVP calculate the nuclear core characteristics correctly for the high-moderation MOX core MISTRAL-3. No apparent trend with the moderation ratio is observed in these calculation results.

Ishii, K.; Tatsumi, M.; Hibi, K.; Sakurada, K.; Yamamoto, T.; Iwata, Y.; Ueji, M.

2001-06-17

156

Analysis of High-Moderation MOX Core MISTRAL-3 with SRAC and MVP

International Nuclear Information System (INIS)

To obtain reactor physics parameters for high-moderation mixed-oxide (MOX) cores, Nuclear Power Engineering Corporation (NPEC), the French Atomic Commission (CEA), and their industrial partners have conducted a MOX core physics experimental program called MISTRAL with the EOLE critical facility of the Cadarache research center. This program consists of four high-moderation cores and was successfully completed in July 2000. This paper describes the analysis results of MISTRAL-3 that is a homogeneous full MOX cylindrical core (H/HM = 6.2) with an 80-cm height and a 59-cm diameter consisting of 1388 standard pressurized water reactor-type MOX fuel rods of 7.0 wt% plutonium-enrichment in a square pitch of 1.39 cm. NPEC has been analyzing the experimental results by using the SRAC and MVP code systems. SRAC and MVP calculate the nuclear core characteristics correctly for the high-moderation MOX core MISTRAL-3. No apparent trend with the moderation ratio is observed in these calculation results

157

Marine Observation Satellite-1 (MOS-1) is scheduled for launch in the January and February period of 1987. Main objectives of the MOS-1 are to observe the sea, land and atmosphere by three radiometers (MESSR, VTIR and MSR) and to develop fundamental technologies for earth observation system consisting of space and ground segments. In order to accomplish these objectives NASDA is developing both MOS-1 and ground facilities, and NASDA conducted MOS-1 airborne verification experiment to develop various algorithms which were converted into MOS-1 data processing facility and then used in MOS-1 verification program (MVP). The purposes of the MVP are to evaluate and confirm the distortion correction methods and performance evaluation methods, to evaluate effectiveness of parameters of MOS-1 mission equipment and to reflect the results of the evaluation on the development and operation of the future earth observation system. Concerning radiometric performance, correction methods of deviation of CCD sensitivity for MESSR, calibration methods for VTIR and MSR have been developed and evaluation methods of S/N and dynamic range have been studied. Concerning geometric performance, geometric distortions are classified and distortion correction methods have been developed. Moreover, spatial resolution have been evaluated. In this paper, some of the geometric and radiometric performance evaluation methods are presented and evaluated.

Maeda, Korehiro; Kojima, Masahiro; Azuma, Yoshio

158

Directory of Open Access Journals (Sweden)

Full Text Available This study examines the factors influencing rural dwellers participation in Millennium Village Project (MVP in Pampaida of Kaduna State, Nigeria. Specifically the socio-economic characteristic of the beneficiaries of the project were identified; and factors influencing rural dwellers participation in the project examined. Data collection process was through the use of structured questionnaire. The study used 120 questionnaires administered to randomly selected respondents in 28 settlements divided into 4 clusters of 7 settlements each. Descriptive statistics and multiple regressions were used to analyze the data. The findings show that most of the respondents were experienced young small scale male adult farmers with little formal education (42% and massive contact with extension agents. Furthermore, age, income, educational attainment, farm size and extension contact were the reasons why the respondents participated in the MVP. Therefore, the following recommendations were made: more adult education centers should be established in the area, as well as more facilitators employed to increase the educational level of the programme participants; soft loans should be granted to the farmers to offset the bureaucratic procedures for credit facilities.

Barnabas, Tena M.

2014-12-01

159

SWAT2: The improved SWAT code system by incorporating the continuous energy Monte Carlo code MVP

International Nuclear Information System (INIS)

SWAT is a code system, which performs the burnup calculation by the combination of the neutronics calculation code, SRAC95 and the one group burnup calculation code, ORIGEN2.1. The SWAT code system can deal with the cell geometry in SRAC95. However, a precise treatment of resonance absorptions by the SRAC95 code using the ultra-fine group cross section library is not directly applicable to two- or three-dimensional geometry models, because of restrictions in SRAC95. To overcome this problem, SWAT2 which newly introduced the continuous energy Monte Carlo code, MVP into SWAT was developed. Thereby, the burnup calculation by the continuous energy in any geometry became possible. Moreover, using the 147 group cross section library called SWAT library, the reactions which are not dealt with by SRAC95 and MVP can be treated. OECD/NEA burnup credit criticality safety benchmark problems Phase-IB (PWR, a single pin cell model) and Phase-IIIB (BWR, fuel assembly model) were calculated as a verification of SWAT2, and the results were compared with the average values of calculation results of burnup calculation code of each organization. Through two benchmark problems, it was confirmed that SWAT2 was applicable to the burnup calculation of the complicated geometry. (author)

160

Monte Carlo Analysis of HTTR with the MVP Statistical Geometry Model

International Nuclear Information System (INIS)

The Japan Atomic Energy Research Institute high-temperature engineering test reactor (HTTR) is a block-type gas-cooled reactor, whose 290-cm-high, 230-cm-effective-diameter active core consists of 30 fuel columns and 7 control rod guide columns. Each fuel column is a hexagonal prism and consists of 5 fuel blocks and 4 graphite reflector blocks. Each fuel block includes 31 or 33 fuel rods. A fuel rod consists of a graphite sleeve containing 14 fuel compacts, each of which includes ?13 000 coated fuel particles (CFPs). The heterogeneity effect of CFPs and fuel rods, which strongly depends on U-enrichment, rod pitch, etc., should be taken into account for an accurate analysis. In order to evaluate the heterogeneity effect on the nuclear characteristics of the HTTR accurately, we used the MVP continuous energy Monte Carlo code. A great number of randomly distributed CFPs were treated by the statistical geometry model (STGM) without spoiling the advantage of the continuous energy method. In summary, the heterogeneity effect of CFPs and fuel rods is evaluated to be ?1%?k/kk' in the cold HTTR core by using the STGM of the MVP code with both the theoretical nearest-neighbor distribution and that from the high-cost MCRDF calculation. It is also found from the cell burnup calculations that the difference of k? caused by the heterogeneity is almost constant up to the maximum burnup of HTTR

161

International Nuclear Information System (INIS)

A - Description of program or function: (1) Problems to be solved: MVP/GMVP can solve eigenvalue and fixed-source problems. The multigroup code GMVP can solve forward and adjoint problems for neutron, photon and neutron-photon coupled transport. The continuous-energy code MVP can solve only the forward problems. Both codes can also perform time-dependent calculations. (2) Geometry description: MVP/GMVP employs combinatorial geometry to describe the calculation geometry. It describes spatial regions by the combination of the 3-dimensional objects (BODIes). Currently, the following objects (BODIes) can be used. - BODIes with linear surfaces: half space, parallelepiped, right parallelepiped, wedge, right hexagonal prism; - BODIes with quadratic surface and linear surfaces: cylinder, sphere, truncated right cone, truncated elliptic cone, ellipsoid by rotation, general ellipsoid; - Arbitrary quadratic surface and torus. The rectangular and hexagonal lattice geometry can be used to describe the repeated geometry. Furthermore, the statistical geometry model is available to treat coated fuel particles or pebbles for high temperature reactors. (3) Particle sources: The various forms of energy-, angle-, space- and time-dependent distribution functions can be specified. (4) Cross sections: The ANISN-type PL cross sections or the double-differential cross sections can be used in the multigroup code GMVP. On the other hand, the specific cross section libraries are used in the contoss section libraries are used in the continuous-energy code MVP. The libraries are generated from the evaluated nuclear data (JENDL-3.3, ENDF/B-VI, JEF-3.0 etc.) by using the LICEM code. The neutron cross sections in the unresolved resonance region are described by the probability table method. The neutron cross sections at arbitrary temperatures are available for MVP by just specifying the temperatures in the input data. (5) Boundary conditions: Vacuum, perfect reflective, isotropic reflective (white), periodic boundary conditions can be specified. (6) Variance reduction techniques: The basic variance reduction techniques Russian roulette kill and splitting are implemented. In addition, importance and weight window based on them are available. Path stretching and source biasing can be also used. (7) Estimator: The track length, collision, point and surface crossing estimators are available. The eigenvalue is estimated by the track length, collision and analog estimators for neutron production and neutron balance methods. In the final estimation, the most probable value and its variance are calculated by the maximum likelihood method with the combination of the estimators. (8) Tallies: GMVP calculates the eigenvalue, the particle flux and reaction rates in each spatial region, each energy group and each time bin for each material, each nuclide and each type of reactions, and their variances as the basic statistical parameters. In addition to these physical quantities, MVP calculates the effective microscopic and macroscopic cross sections and the corresponding reaction rates in the specified regions. These quantities are basically tallied for each spatial region but can be tallied for the arbitrary combination of the regions with options. Furthermore, the calculated quantities are output to files and can be then used for the input data of a drawing program mentioned later or a burnup calculation code MVP-BURN. (9) Drawing geometry: The CGVIEW code draws the cross-sectional view on an arbitrary plane and output it on a display or in the postscript or encapsulated postscript form. These functions are useful for checking the calculation geometry. (10) Burnup calculation: The auxiliary code MVP-BURN implemented in the MVP/GMVP system is available for burnup calculations. (11) Parallelism: Parallel calculations can be performed with standard libraries MPI and PVM. (12) Other capabilities: MVP/GMVP has a capability of reactor noise analysis based on simulation of Feynman-alpha experiments. B - Methods: MVP and GMVP are based on the continuous-energy and multigrou

162

Energy Technology Data Exchange (ETDEWEB)

Experimental cross section (CS) and vector analyzing power (VAP) data of the {sup 6}Li-{sup 28}Si elastic scattering at 22.8 MeV are analyzed in the coupled-channels (CC) and coupled discretized continuum channels (CDCC) methods. Non-monotonic (NM) {sup 6}Li and {alpha} potentials of microscopic origin are employed, respectively, in the CC calculations and to generate folding potentials for the CDCC calculations. The study demonstrates that the use of central NM potentials can generate an appropriate dynamic polarization potential (DPP) required to describe both the CS and VAP data without the necessity of renormalization. This also produces an effective spin-orbit (SO) potential to account for the iT{sub 11} data without the requirement of an additional static SO potential at the incident energy considered.

Basak, A.K., E-mail: akbasak@gmail.co [Department of Physics, University of Rajshahi, Rajshahi (Bangladesh); Roy, P.K. [Department of Physics, B.L. College, Daulatpur, Khulna (Bangladesh); Hossain, S. [Department of Physics, Shahjalal University of Science and Technology, Sylhet (Bangladesh); Abdullah, M.N.A. [Department of Physics, Rajshahi University of Engineering and Technology, Rajshahi (Bangladesh); Tariq, A.S.B.; Uddin, M.A. [Department of Physics, University of Rajshahi, Rajshahi (Bangladesh); Reichstein, I. [School of Computer Science, Carleton University, Ottawa, ON K1S 5B6 (Canada); Malik, F.B. [Department of Physics, Southern Illinois University, Carbondale, IL 62901 (United States); Department of Physics, Washington University, St. Louis, MO 63130 (United States)

2010-08-16

163

Directory of Open Access Journals (Sweden)

Full Text Available With the advent of Computer Algebra System (CAS such as Mathematica [1], challenging symbolic longhand calcula-tions can effectively be performed free of error and at ease. Mathematica’s integrated features allow the investigator to combine the needed symbolic, numeric and graphic modules all in one interactive environment. This assists the author to focus on interpreting the output rather than exerting the efforts of relating the scattered separate modules. In this note the author, utilizing these three features, explores the magneto-static field and its associated vector potential of a steady looping current. In particular by deploying the numeric features of Mathematica the exact value of the vector potential of the looping current conducive to its 3D graph is presented.

Haiduke Sarafian

2011-05-01

164

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Phlebotomine sand flies (Diptera, Psychodidae) from Rio de Janeiro State, Brazil: Species distribution and potential vectors of leishmaniases. Rio de Janeiro State, in Brazil, has endemic areas of both cutaneous and visceral leishmaniases. In these areas, entomologic surveillance actions are highly [...] recommended by Brazil's Ministry of Health. The present work describes the results of sand fly captures performed by the Health Department of Rio de Janeiro State between 2009 and 2011 in several municipalities. An updated species list and distribution of phlebotomine sand flies in the state are provided based on an extensive literature review. Currently, the sand fly fauna of Rio de Janeiro State has 65 species, belonging to the genera Brumptomyia (8 spp.) and Lutzomyia (57 spp.). Distribution maps of potential leishmaniases vector species Lutzomyia (Nyssomyia) intermedia, L. migonei, L. (N.) whitmani, L. (N.) flaviscutellata and L. (Lutzomyia) longipalpis are provided and their epidemiological importance is discussed.

Bruno Moreira, Carvalho; Cristina Maria Giordano, Dias; Elizabeth Ferreira, Rangel.

2014-03-01

165

The usual approximation scheme is used to study the solution of the Duffin-Kemmer-Petiau (DKP) equation for a vector Yukawa potential in the framework of the parametric Nikiforov-Uvarov (NU) method. The approximate energy eigenvalue equation and the corresponding wave function spinor components are calculated for arbitrary total angular momentum in closed form. Further, the approximate energy equation and wave function spinor components are also given for case. A set of para...

Hamzavi, Majid; Ikhdair, Sameer M.

2012-01-01

166

To identify the host range of potential vectors of Diro?laria immitis Leidy, the causal agent of canine diroÞlariasis, we studied the bloodmeal origin of mosquitoes trapped on two of the Canary Islands, Gran Canaria and Tenerife, where this disease is considered hyperendemic. On Gran Canaria, mosquitoes were captured using Centers for Disease Control and Prevention (CDC) traps (outdoors) and resting in a bathroom (indoors). Only CDC traps were used to capture mosquitoes in Tenerife. The ...

Marti?nez La Puente, Josue?; Moreno-indias, Isabel; Herna?ndez-castellano, Lorenzo E.; Argu?ello, Anastasio; Rui?z, Santiago; Soriguer, Ramo?n C.; Figuerola, Jordi

2012-01-01

167

f(R) gravity on non-linear scales: The post-Friedmann expansion and the vector potential

Many modified gravity theories are under consideration in cosmology as the source of the accelerated expansion of the universe and linear perturbation theory, valid on the largest scales, has been examined in many of these models. However, smaller non-linear scales offer a richer phenomenology with which to constrain modified gravity theories. Here, we consider the Hu-Sawicki form of $f(R)$ gravity and apply the post-Friedmann approach to derive the leading order equations for non-linear scales, i.e. the equations valid in the Newtonian-like regime. We reproduce the standard equations for the scalar field, gravitational slip and the modified Poisson equation in a coherent framework. In addition, we derive the equation for the leading order correction to the Newtonian regime, the vector potential. We measure this vector potential from $f(R)$ N-body simulations at redshift zero and one, for two values of the $f_{R_0}$ parameter. We find that the vector potential at redshift zero in $f(R)$ gravity can be close t...

Thomas, Daniel B; Koyama, Kazuya; Li, Baojiu; Zhao, Gong-Bo

2015-01-01

168

Analysis of the TRIGA Mark-II benchmark IEU-COMP-THERM-003 with Monte Carlo code MVP

International Nuclear Information System (INIS)

The benchmark experiments of the TRIGA Mark-II reactor in the ICSBEP handbook have been analyzed with the Monte Carlo code MVP using the cross section libraries based on JENDL-3.3, JENDL-3.2 and ENDF/B-VI.8. The MCNP calculations have been also performed with the ENDF/B-VI.6 library for comparison between the MVP and MCNP results. For both cores labeled 132 and 133, which have different core configurations, the ratio of the calculated to the experimental results (C/E) for keff obtained by the MVP code is 0.999 for JENDL-3.3, 1.003 for JENDL-3.2, and 0.998 for ENDF/B-VI.8. For the MCNP code, the C/E values are 0.998 for both Core 132 and 133. All the calculated results agree with the reference values within the experimental uncertainties. The results obtained by MVP with ENDF/B-VI.8 and MCNP with ENDF/B-VI.6 differ only by 0.02% for Core 132, and by 0.01% for Core 133. (author)

169

We present an alternative and simple method for the exact solution of the Klein-Gordon equation in the presence of the non-central equal scalar and vector potentials by using Nikiforov-Uvarov (NU) method. The exact bound state energy eigenvalues and corresponding eigenfunctions are obtained for a particle bound in a potential of $V(r,\\theta) = \\frac{\\alpha}{r} + \\frac{\\beta}{r^2\\sin ^2\\theta} + \\gamma \\frac{\\cos \\theta}{r^2\\sin ^2\\theta}$ type.

Yasuk, Fevziye; Durmus, Aysen; Boztosun, Ismail

2006-01-01

170

Dengue virus is an emerging disease of concern in the Americas. Recent outbreaks in Florida highlight the potential for the virus to return to the United States. The Lower Rio Grande Valley region of Texas directly borders Mexico, and has experienced dengue transmission in the past concurrent with outbreaks in Mexico along the border region. We examined the potential for dengue virus transmission by examining the vectors in the region, as well as assessing human behavior. We further hypothesized that dengue vector abundance would influence human behavior. Two dengue vectors, Aedes aegypti (L.) and Aedes albopictus (Skuse), were found in the region in high abundance. More mosquitoes were collected in rural sites and sites with high vegetation. Of the two species, only Ae. albopictus showed any significant habitat preferences, being more common in rural site. While there was no correlation between human behavior and mosquito abundance, the results support a significant correlation between knowledge of mosquitoes and dengue virus and behavioral practices that might reduce risk of disease transmission. Dengue risk may be higher in certain regions of the Lower Rio Grande Valley based on socioeconomic conditions, specifically in economically poor regions such as the undeveloped colonias found in the region. Because of the proximity of this region to an area with endemic dengue, continued surveillance and risk assessment is suggested. PMID:25276932

Vitek, Christopher J; Gutierrez, Joann A; Dirrigl, Frank J

2014-09-01

171

We have developed a potential tumor-targeting peptide vector (cRGD-hK) that is intended to be systemically and repeatedly administered to patients with advanced solid tumors. The peptide vector of 36 l-amino acid residues, CRGDCF(K[H-]KKK)6, comprises a tumor-homing RGD motif, a DNA-binding oligolysine, and histidyl residues to facilitate the delivery into the cytosol. Using cytomegalovirus-driven luciferase expression plasmids as a reporter, we tested the transfection efficiency of cRGD-hK in hepatoma and pancreatic cancer cell lines. Transfection with the cRGD-hK/plasmid complexes (molar ratio 4000:1) was inhibited by 50 nM bafilomycin A1, an inhibitor of the vacuolar ATPase endosomal proton pump, or 10 microM cycloRGDfV, an integrin alphavbeta3 antagonist, indicating that the three elements of cRGD-hK could function as expected, at least in vitro. In nude mice bearing tumors created by subcutaneous inoculation, luciferase activity in the tumor tissues 48 hours after the injection of the cRGD-hK/plasmid complexes through the tail vein (20 microg plasmids per mouse) was significantly higher than that in the lung, kidney, and spleen, but only slightly higher than that in the liver. Although the latter difference was small, we propose a potential nonviral gene therapy for advanced solid tumors through use of the tumor-targeting peptide vector. PMID:11687901

Aoki, Y; Hosaka, S; Kawa, S; Kiyosawa, K

2001-10-01

172

We modelled the ecoclimatic niche of Culicoides imicola, a major arthropod vector of midge-borne viral pathogens affecting ruminants and equids, at fine scale and on a global extent, so as to provide insight into current and future risks of disease epizootics, and increase current knowledge of the species' ecology. Based on the known distribution and ecology of C. imicola, the species' response to monthly climatic conditions was characterised using CLIMEX with 10? spatial resolution climatic datasets. The species' climatic niche was projected worldwide and under future climatic scenarios. The validated model highlights the role of irrigation in supporting the occurrence of C. imicola in arid regions. In Europe, the modelled potential distribution of C. imicola extended further West than its reported distribution, raising questions regarding ongoing process of colonization and non-climatic habitat factors. The CLIMEX model highlighted similar ecological niches for C. imicola and the Australasian C. brevitarsis raising questions on biogeography and biosecurity. Under the climate change scenarios considered, its' modelled potential distribution could expand northward in the Northern hemisphere, whereas in Africa its range may contract in the future. The biosecurity risks from bluetongue and African horse sickness viruses need to be re-evaluated in regions where the vector's niche is suitable. Under a warmer climate, the risk of vector-borne epizootic pathogens such as bluetongue and African horse sickness viruses are likely to increase as the climate suitability for C. imicola shifts poleward, especially in Western Europe. PMID:25391148

Guichard, Sylvain; Guis, Hélène; Tran, Annelise; Garros, Claire; Balenghien, Thomas; Kriticos, Darren J.

2014-01-01

173

The use of vectors not only simplifies treatments of differential geometry, mechanics, hydrodynamics, and electrodynamics, but also makes mathematical and physical concepts more tangible and easy to grasp. This text for undergraduates was designed as a short introductory course to give students the tools of vector algebra and calculus, as well as a brief glimpse into these subjects' manifold applications. The applications are developed to the extent that the uses of the potential function, both scalar and vector, are fully illustrated. Moreover, the basic postulates of vector analysis are brou

Brand, Louis

2012-01-01

174

In 32 collections, two larvae, 33 nymphs, and one adult female Ixodes cookei Packard were collected from humans in West Virginia from August 1987 to May 1990. Most were attached. The ticks were found in 14 counties and were the most abundant Ixodes found biting humans. One nymphal I. cookei was removed from the left axilla of a 39-yr-old woman who lives and works in Monongalia and Marion counties, W. Va. The bite was the center of an expanding erythematous lesion reaching 4 cm in diameter, clearing centrally, and typical of erythema migrans. This association and the near absence of Ixodes dammini Spielman, Clifford, Piesman & Corwin from the state suggests the possibility that I. cookei may be an important vector of Lyme borreliosis in West Virginia. In five separate collections, five nymphal Ixodes dentatus Marx were removed from humans in four counties, implicating this species as a potential minor vector of Lyme borreliosis in West Virginia. PMID:2033612

Hall, J E; Amrine, J W; Gais, R D; Kolanko, V P; Hagenbuch, B E; Gerencser, V F; Clark, S M

1991-01-01

175

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to be introduced into Mexico City by various means including infected mosquitoes on airplanes, migrating birds, ground transportation and infected humans. Little is known of the geographic distribution of Culex pipiens complex mosquitoes and hybrids in Mexico City. Culex pipiens pipiens preferentially feed on avian hosts; Culex pipiens quinquefasciatus have historically been considered to prefer mammalian hosts; and hybrids of these two species could theoretically serve as bridge vectors to transmit WNV from avian hosts to humans and other mammalian hosts. In order to address the potential of WNV being introduced into Mexico City, we have determined the identity and spatial distribution of Culex pipiens complex mosquitoes and their hybrids. Results Mosquito larvae collected from 103 sites throughout Mexico City during 2004-2005 were identified as Culex, Culiseta or Ochlerotatus by morphological analysis. Within the genus Culex, specimens were further identified as Culex tarsalis or as belonging to the Culex pipiens complex. Members of the Culex pipiens complex were separated by measuring the ratio of the dorsal and ventral arms (DV/D ratio of the male genitalia and also by using diagnostic primers designed for the Ace.2 gene. Culex pipiens quinquefasciatus was the most abundant form collected. Conclusions Important WNV vectors species, Cx. p. pipiens, Cx. p. quinquefasciatus and Cx. tarsalis, are all present in Mexico City. Hybrids of Cx. p. pipiens and Cx. p. quinquefasciatus were also collected and identified. The presence and abundance of these WNV competent vectors is a cause for concern. Understanding the distribution of these vectors can help improve viral surveillance activities and mosquito control efforts in Mexico City.

Diaz-Perez Alfonso

2011-05-01

176

We prescribe a pseudo-Newtonian vector potential for studying accretion disks around Kerr black holes. The potential is useful to study the inner properties of disk not confined to the equatorial plane where general relativistic effect is indispensable. Therefore, we incorporate the essential properties of the metric at the inner radii through the pseudo-Newtonian potential derived from the general Kerr spacetime. The potential, reproducing most of the salient features of the general-relativity, is valid for entire regime of Kerr parameter. It reproduces the last stable circular orbit exactly as that in the Kerr geometry. It also reproduces last bound orbit and energy at last stable circular orbit with a maximum error ~7% and ~15% respectively upto an orbital inclination 30 degree.

Ghosh, Shubhrangshu

2007-01-01

177

Feeding Patterns of Potential West Nile Virus Vectors in South-West Spain

Background: Mosquito feeding behaviour determines the degree of vector–host contact and may have a serious impact on the risk of West Nile virus (WNV) epidemics. Feeding behaviour also interacts with other biotic and abiotic factors that affect virus amplification and transmission. Methodology/Principal Findings: We identified the origin of blood meals in five mosquito species from three different wetlands in SW Spain. All mosquito species analysed fed with different frequencies on bir...

Mun?oz, Joaqui?n; Rui?z, Santiago; Soriguer, Ramo?n C.; Alcaide, Miguel; Viana, Duarte S.; Roiz, David; Va?zquez, Ana; Figuerola, Jordi

2012-01-01

178

Stochastic and Deterministic Vector Chromatography of Suspended Particles in 1D-Periodic Potentials

We present a comprehensive description of vector chromatography that includes deterministic and stochastic transport in 1D-periodic free-energy landscapes, with both energetic and entropic contributions, and highlights the parameters governing the deflection angle, i.e. the Peclet number and the partition ratio. We also investigate the dependence of the deflection angle on the shape of the free-energy landscape by varying the width of the linear transitions in an otherwise d...

Bernate, Jorge A.; Drazer, German

2011-01-01

179

Nielsen identities for gauge-fixing vectors and composite effective potentials

International Nuclear Information System (INIS)

We show how to derive the Nielsen identities which govern the gauge dependence of physical quantities and the effective action for the gauge fixing vectors in both the 't Hooft gauge and in the planar gauge by using an extended set of BRS transformations. We also show that it is possible to derive the identities for an effective action which depends on composite operators. (orig.)

180

UNLABELLED: ABSTRACT: BACKGROUND: Anopheles plumbeus has been recognized as a minor vector for human malaria in Europe since the beginning of the 20th century. In recent years this tree hole breeding mosquito species appears to have exploited novel breeding sites, including large and organically rich man-made containers, with consequently larger mosquito populations in close vicinity to humans. This lead to investigate whether current populations of An. plumbeus would be able to efficiently t...

Schaffner, Francis; Thie?ry, Isabelle; Kaufmann, Christian; Zettor, Agne?s; Lengeler, Christian; Mathis, Alexander; Bourgouin, Catherine

2012-01-01

181

A Single Mutation in Chikungunya Virus Affects Vector Specificity and Epidemic Potential

Chikungunya virus (CHIKV) is an emerging arbovirus associated with several recent large-scale epidemics. The 2005–2006 epidemic on Reunion island that resulted in approximately 266,000 human cases was associated with a strain of CHIKV with a mutation in the envelope protein gene (E1-A226V). To test the hypothesis that this mutation in the epidemic CHIKV (strain LR2006 OPY1) might influence fitness for different vector species, viral infectivity, dissemination, and transmission of CHIKV were...

Tsetsarkin, Konstantin A.; Vanlandingham, Dana L.; Mcgee, Charles E.; Higgs, Stephen

2007-01-01

182

Mosquitoes as a Potential Vector of Ranavirus Transmission in Terrestrial Turtles.

Ranaviruses are significant pathogens of amphibians, reptiles, and fishes, contributing to mass mortality events worldwide. Despite an increasing focus on ranavirus ecology, our understanding of ranavirus transmission, especially among reptilian hosts, remains limited. For example, experimental evidence for oral transmission of the virus in chelonians is mixed. Consequently, vector-borne transmission has been hypothesized in terrestrial turtle species. To test this hypothesis, mosquitoes captured during a 2012/2013 ranavirus outbreak in box turtles from southwestern Indiana were pooled by genus and tested for ranavirus DNA using qPCR. Two of 30 pools tested positive for ranavirus. Additionally, an individual Aedes sp. mosquito observed engorging on a box turtle also tested positive for ranavirus. Although our approach does not rule out the possibility that the sequenced ranavirus was simply from virus in bloodmeal, it does suggests that mosquitoes may be involved in virus transmission as a mechanical or biological vector among ectothermic vertebrates. While additional studies are needed to elucidate the exact role of mosquitoes in ranavirus ecology, our study suggests that a greater focus on vector-borne transmission may be necessary to fully understand ranaviral disease dynamics in herpetofauna. PMID:25212726

Kimble, Steven J A; Karna, Ajit K; Johnson, April J; Hoverman, Jason T; Williams, Rod N

2014-09-12

183

Processors for wavelet analysis and synthesis: NIFS and TI-C80 MVP

Two processors are considered for image quadrature mirror filtering (QMF). The neuromorphic infrared focal-plane sensor (NIFS) is an existing prototype analog processor offering high speed spatio-temporal Gaussian filtering, which could be used for the QMF low- pass function, and difference of Gaussian filtering, which could be used for the QMF high- pass function. Although not designed specifically for wavelet analysis, the biologically- inspired system accomplishes the most computationally intensive part of QMF processing. The Texas Instruments (TI) TMS320C80 Multimedia Video Processor (MVP) is a 32-bit RISC master processor with four advanced digital signal processors (DSPs) on a single chip. Algorithm partitioning, memory management and other issues are considered for optimal performance. This paper presents these considerations with simulated results leading to processor implementation of high-speed QMF analysis and synthesis.

Brooks, Geoffrey W.

1996-03-01

184

A study on the motion vector prediction schemes for AVS

The motion vector prediction (MVP) is an important part of video coding. There have been numerous workings on the topic done by researchers before. In this paper, a continue study on MVP of video coding based on the workings of predecessors is made. The video sequences with various motion characteristics are further investigated. The characteristics of motion vectors of objects in video scenes are discussed briefly. Then, summarizing these characteristics, two MVP schemes for a new coding standard, Audio and Video Standard (AVS), are proposed. In these schemes, current block"s MV can be predicted based on statistical correlation of MVs of spatial contiguous neighbor blocks. A correlation criterion is employed to measure how correlated between two MVs. With the correlation criterion, the correlated MVs of neighbor blocks are determined. Then, the predicted MV of current block can be obtained with some simple algebraic operations on determined MVs. The two proposed schemes, as the alternative ones of median predictor, are suitable for different video sequences with different motion characteristics, respectively. The experimental results show that the bit rate savings are achieved with these schemes in most of typical video sequences, compared with the median predictor implemented in AVS.

Qi, Honggang; Gao, Wen; Ma, Siwei; Zhao, Debin

2005-07-01

185

Maximizing sparse matrix vector product performance in MIMD computers

Energy Technology Data Exchange (ETDEWEB)

A considerable component of the computational effort involved in conjugate gradient solution of structured sparse matrix systems is expended during the Matrix-Vector Product (MVP), and hence it is the focus of most efforts at improving performance. Such efforts are hindered on MIMD machines due to constraints on memory, cache and speed of memory-cpu data transfer. This paper describes a strategy for maximizing the performance of the local computations associated with the MVP. The method focuses on single stride memory access, and the efficient use of cache by pre-loading it with data that is re-used while bypassing it for other data. The algorithm is designed to behave optimally for varying grid sizes and number of unknowns per gridpoint. Results from an assembly language implementation of the strategy on the iPSC/860 show a significant improvement over the performance using FORTRAN.

McLay, R.T.; Kohli, H.S.; Swift, S.L.; Carey, G.F.

1994-12-31

186

International Nuclear Information System (INIS)

The generalized form of Killingbeck potential is an attractive Coulomb term plus a linear term and a harmonic oscillator term, i.e. ?a/r + br + ?r2, which has a useful application in quarkonium spectroscopy. The ground state energy with the corresponding wave function are obtained for any arbitrary m-state in two-dimensional Klein–Gordon equation with equal mixture of scalar–vector Killingbeck potentials in the presence of constant magnetic and singular Ahoronov–Bohm flux fields perpendicular to the plane where the interacting charged particle is confined. The analytical exact iteration method is used in our solution. We obtain the energy eigensolutions for particle and antiparticle corresponding to S(r) = V(r) and S(r) = ?V(r) cases, respectively. Some special cases like the Coulomb, harmonic oscillator potentials and the nonrelativistic limits are found in presence and absence of external fields. (author)

187

International Nuclear Information System (INIS)

Gap opening at the Dirac point of the single-layer graphene with periodic scalar and vector potentials has been theoretically investigated under the continuum model. The symmetry analysis indicates that the two-fold degeneracy at the Dirac point can be lifted when the potentials break both the chiral symmetry and the time-reversal symmetry. With the perturbation theory, we derive an analytical expression (gap equation) for gap opening at the Dirac point. Furthermore, the bandgap from the gap equation agrees well with the exact result, when the applied potentials are weak. -- Highlights: ? We analysis the relationship of the degeneracy of the Dirac point and the symmetry of the Hamiltonian. ? We derive a gap equation at the Dirac point analytically with perturbation theory. ? Our gap equation shows a gap would be opened at the Dirac point with both electric and magnetic superlattice. ? Our gap equation is confirmed by the numerical calculation.

188

International Nuclear Information System (INIS)

The Green's function for a Klein-Gordon particle under the action of vector plus scalar deformed Hulthen and Woods-Saxon potentials is evaluated by exact path integration. Explicit path integration leads to the Green's function for different shapes of the potentials. From the singularities of the latter Green's function, the bound states are extracted. For q?1 and (1/?)ln q< rpotentials are also discussed briefly.

189

The Green's function for a Klein-Gordon particle under the action of vector plus scalar deformed Hulthén and Woods-Saxon potentials is evaluated by exact path integration. Explicit path integration leads to the Green's function for different shapes of the potentials. From the singularities of the latter Green's function, the bound states are extracted. For q ?1 and (1/?)ln q

Benamira, F.; Guechi, L.; Mameri, S.; Sadoun, M. A.

2010-03-01

190

Scrub typhus and tick-borne spotted fever group (SFG) rickettsioses are transmitted by chiggers (larval trombiculid mites) and hard ticks, respectively. We assessed exposure to these disease vectors by extensively sampling both chiggers and ticks and their small mammal hosts in eastern Taiwan during 2007 and 2008. The striped field mouse Apodemus agrarius Pallas (Rodentia: Muridae) was the most common of the small mammals (36.1% of 1393 captures) and presented the highest rate of infestation with both chiggers (47.8% of 110 760) and ticks (78.1% of 1431). Leptotrombidium imphalum Vercammen-Grandjean & Langston (Trombidiformes: Trombiculidae) and immature Rhipicephalus haemaphysaloides Supino (Ixodida: Ixodidae) were the most abundant chiggers (84.5%) and ticks (>99%) identified, respectively. Immunofluorescent antibody assay revealed high seropositive rates of rodents against Orientia tsutsugamushi Hyashi (Rickettsiales: Rickettsiaceae), the aetiological agent of scrub typhus (70.0% of 437 rodents), and tick-borne SFG rickettsiae (91.9% of 418 rodents). The current study represents a first step towards elucidating the potential hosts and vectors in the enzootic transmission of O. tsutsugamushi and tick-borne SFG rickettsiae in Taiwan. Further studies should focus on characterizing pathogens in L. imphalum and R. haemaphysaloides, as well as the proclivity of both vectors to humans. Uncovering the main hosts of adult ticks is also critical for the prevention of SFG rickettsial infections. PMID:21223345

Kuo, C C; Huang, C L; Wang, H C

2011-06-01

191

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Dirofilaria immitis is a widespread mosquito-borne parasite that causes dirofilariasis, a commonly diagnosed disease of dogs that is rarely reported in cats and humans. A mosquito survey was conducted in Itacoatiara in the State of Rio de Janeiro, from March 1995 to February 1996, using canine, feli [...] ne and human baits. A total of 3,667 mosquitoes were dissected for D. immitis larvae, representing 19 species and 10 genera. From those, Ae. scapularis, Ae taeniorhynchus, Cx. quinquefasciatus, Cx. declarator, Cx. saltanensis and Wy. bourrouli were found infected with D. immitis parasites, and among those, only the first three harbored infective larvae. The majority of larvae were found in the Malpighian tubules (889/936), and larval melanization was observed in the two Aedes species. In descending order, the best vectors were Ae. scapularis, Ae. taeniorhynchus, and Cx. quinquefasciatus which alternate seasonally in importance. Cx. quinquefasciatus is suggested to be a vector to cats. The potential transmission of D. immitis parasites by these three vectors to man is discussed.

Norma, Labarthe; Maria Lúcia, Serrão; Yuri Fontenele, Melo; Sebastião José de, Oliveira; Ricardo, Lourenço-de-Oliveira.

1998-07-01

192

Directory of Open Access Journals (Sweden)

Full Text Available Dirofilaria immitis is a widespread mosquito-borne parasite that causes dirofilariasis, a commonly diagnosed disease of dogs that is rarely reported in cats and humans. A mosquito survey was conducted in Itacoatiara in the State of Rio de Janeiro, from March 1995 to February 1996, using canine, feline and human baits. A total of 3,667 mosquitoes were dissected for D. immitis larvae, representing 19 species and 10 genera. From those, Ae. scapularis, Ae taeniorhynchus, Cx. quinquefasciatus, Cx. declarator, Cx. saltanensis and Wy. bourrouli were found infected with D. immitis parasites, and among those, only the first three harbored infective larvae. The majority of larvae were found in the Malpighian tubules (889/936, and larval melanization was observed in the two Aedes species. In descending order, the best vectors were Ae. scapularis, Ae. taeniorhynchus, and Cx. quinquefasciatus which alternate seasonally in importance. Cx. quinquefasciatus is suggested to be a vector to cats. The potential transmission of D. immitis parasites by these three vectors to man is discussed.

Labarthe Norma

1998-01-01

193

Viral vector-mediated gene transfer of neurotrophic factors is an emerging and promising strategy to promote the regeneration of injured peripheral nerves. Unfortunately, the chronic exposure to neurotrophic factors results in local trapping of regenerating axons or other unwanted side effects. Therefore, tight control of therapeutic gene expression is required. The tetracycline/doxycycline-inducible system is considered to be one of the most promising systems for regulating heterologous gene expression. However, an immune response directed against the transactivator protein rtTA hampers further translational studies. Immunogenic proteins fused with the Gly-Ala repeat of the Epstein-Barr virus Nuclear Antigen-1 protein have been shown to successfully evade the immune system. In this article, we used this strategy to demonstrate that a chimeric transactivator, created by fusing the Gly-Ala repeat with rtTA and embedded in a lentiviral vector (i) retained its transactivator function in vitro, in muscle explants, and in vivo following injection into the rat peripheral nerve, (ii) exhibited a reduced leaky expression, and (iii) had an immune-evasive advantage over rtTA as shown in a novel bioassay for human antigen presentation. The current findings are an important step toward creating a clinically applicable potentially immune-evasive tetracycline-regulatable viral vector system. PMID:24694534

Hoyng, S A; Gnavi, S; de Winter, F; Eggers, R; Ozawa, T; Zaldumbide, A; Hoeben, R C; Malessy, M J A; Verhaagen, J

2014-06-01

194

Directory of Open Access Journals (Sweden)

Full Text Available INTRODUCTION: Cyclopid copepods are known to be good mosquito controllers, specially as regards the larvae of the dengue vectors Aedes aegypti and Ae. albopictus. MATERIAL AND METHOD: The objective of the study was to survey the local copepod fauna and search for new strains of M. longisetus var. longisetus, comparing the potential of the samples found with the current strain ML-01 against Ae. albopictus larvae, under laboratory conditions. Eleven bodies of water in Campinas, SP, Brazil, were screened for copepods by collecting 1.5 l of water from each of then. The predatory potential of adults copepods was evaluated over 24 h, in the laboratory, for groups of 5 individuals preying upon 30 first instar Ae. albopictus larvae. RESULTS AND CONCLUSION: The following cyclopid species were found: Metacyclops mendocinus, Tropocyclops prasinus, Eucyclops sp, Eucyclops serrulatus, Eucyclops solitarius, Eucyclops ensifer, Macrocyclops albidus var. albidus and Mesocyclops longisetus var. longisetus. The predatory potential of these copepods ranged from nil to 97.3%. A sample collected in the field containing only M. longisetus var. longisetus showed the best control efficiency with no significant difference from a three-year old laboratory culture (ML-01 of the same species evaluated for comparison. The sample with few M. albidus var. albidus was ranked in second place showing an average 25.9% efficiency. The use of copepods in trap tires as dengue vector controllers is discussed.

Santos Luciana Urbano dos

1997-01-01

195

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Full Text Available The energy conservation method is based on knowledge of the state vector and measurements of nonconservative forces. This is or will be provided by CHAMP, GRACE and GOCE. Here the analysis of one month of CHAMP state vector and accelerometer data is described. The energy conservation method is used to estimate the gravity potential at satellite altitude. When doing so we consider the tidal potential from the sun and the moon, the explicit time variation of the gravity potential in inertial space and loss of energy due to external forces. Fast Spherical Collocation have been used to estimate a gravity field model to degree and order 90, UCPH2002 04. This gravity field model is compared to EGM96 and EIGEN-2. The largest differences with respect to EGM96 are found at those places where the gravity data used to determine EGM96 had the largest uncertainty. EIGEN-2 and UCPH2002 04 are similar, though there are some differences in Antarctica and Central Asia.

E. Howe

2003-01-01

196

The masses of vector mesons in holographic QCD at finite chiral chemical potential

Central heavy-ion collisions may induce sizeable fluctuations of the topological charge. This effect is expected to distort the dispersion relation for the hadron masses. We construct a general setup for a compact description of this phenomenon in the framework of bottom-up holographic approach to QCD. A couple of soft wall holographic models are proposed for the vector mesons. The states having different circular polarizations are shown to have different effective mass. The requirement of stability imposes strong constraints on the possible choice of models.

Afonin, S S; Espriu, D

2015-01-01

197

Hsp70 in immunotherapy : a potential vector in cancer and viral vaccines

New efficient vaccines against cancers and infectious diseases are in demand. In 1993 heat shock protein 70 (hsp70) purified from tumour was shown to elicit tumour protection in mice. It was also shown that the protection was not mediated by the hsp70 itself, but by tumour-specific peptides bound to the molecule. In this thesis 1 have studied hsp70 in two different tumour systems and in one viral system to find out if this chaperone has the capacity to act as a useful vector...

Ciupitu, Anne-marie T.

2000-01-01

198

Relativistic and radiative corrections to potential model leptonic widths of vector mesons

International Nuclear Information System (INIS)

Relativistic and radiative corrections of the nonrelativistic (Van Royen-Weiskopf) formula for the leptonic widths vector meson (n3S1) bound states are calculated using Q2-duality. They are determined by the Schwinger function. This function possesses a simple factorization which allows us to identify a wave function at the origin and hence to isolate the genuine radiative correction factor. This latter agrees with the formula of Karplus and Klein in the appropriate limit. For the quarkonium states it provides a reliable estimate of QCD radiative-corrections. For the psi and UPSILON states these corrections are large. The same is true of the relativistic corrections

199

International Nuclear Information System (INIS)

The usual approximation scheme is used to study the solution of the Duffin–Kemmer–Petiau (DKP) equation for a vector Yukawa potential in the framework of the parametric Nikiforov-Uvarov (NU) method. The approximate energy eigenvalue equation and the corresponding wave function spinor components are calculated for any total angular momentum J in closed form. Further, the exact energy equation and wave function spinor components are also given for the J = 0 case. A set of parameter values is used to obtain the numerical values for the energy states with various values of quantum levels (n, J). (author)

200

International Nuclear Information System (INIS)

ABCXYZ is a computer code for obtaining the Cartesian components of the vector potential and the magnetic field on an observed grid from an arrangement of current-carrying wires. Arbitrary combinations of straight line segments, arcs, and loops are allowed in the specification of the currents. Arbitrary positions and orientations of the current-carrying elements are also allowed. Specification of the wire diameter permits the computation of well-defined fields, even in the interiors of the conductors. An optical feature generates magnetic field lines. Extensive graphical and printed output is available to the user including contour, grid-line, and field-line plots. 12 figures, 1 table

201

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Full Text Available The first molecular analysis of samples collected in southern Ba?ka (Serbia confirmed the presence of aster yellows (16SrI and stolbur phytoplasmas (16SrXII in insects belonging to the family Cicadellidae, as well as in carrot plants where the insects were collected. A correct identification of the phytoplasmas and their vectors is essential to arrange effective control strategies to prevent diseases associated with phytoplasmas from spreading to carrots and other vegetable crops. In order to enhance knowledgeabout insect vectors of aster yellows and stolbur phytoplasmas in Serbia, Cicadellidae and Cixiidae (Homoptera Auchenorrhyncha, the most common vectors of these phytoplasmas,were monitored in southern Ba?ka during 2008. Adults leaf- and planthoppers were collected and identified at species level using standard entomological methods,and tested for phytoplasma presence by means of PCR/RFLP. A total of 13 insect species of Cicadellidae were identified, as follows: a three species of the subfamily Agallinae: Anaceratagallia ribauti (Ossiannilsson, Anaceratagallia venosa (Fourcroy,and Anaceratagallia laevis (Ribaut; b seven species of the subfamily Deltocephalinae: Psammotettix confinis (Dahlbom, Psammotettix striatus (Linnaues Psammottettix alienus (Dahlbom, Macrosteles sexnotatus (Fallén, Ophiola decumana (Kontkanen,Errastunus ocellaris Fallén, and Scaphoideus titanus Ball; c three species of the subfamily Typhlocibinae: Eupteryx atropunctata (Goeze, Eupteryx mellissae Curtis, Zyginidia pullula (Boheman. Female specimens of the genus Euscelis (Deltocephalinae were also collected, as well as one species of Reptalus quinquecostatus (Dufour of the family Cixiidae. Stolbur phytoplasmas were detected in A. laevis, A. ribauti, A. venosa, P. striatus, P. confinis and P. alienus. The species: A. laevis, O. decumana, and P. confinis were AY-infected (subgroup 16SrI-A, while subgroup 16SrI-C was found only in one specimen of P. confinis. Since some aster yellows- and stolbur-infected species of the genera Psammotettix and Anaceratagallia (especially P. confinis and A. laevis were regularly and commonly found in the infected carrot fields during the whole vegetative period, they could play a significant role in transmitting and spreading these pathogens in natural environment.

Tanja Drobnjakovi?

2010-01-01

202

International Nuclear Information System (INIS)

Highlights: • Support vector machine is used to estimate daily solar radiation from sunshine duration. • Seven SVM models using different input attributes are evaluated using 35 years long term data. • SVM models significantly outperform the empirical models. • The optimal SVM model is proposed. - Abstract: Estimation of solar radiation from sunshine duration offers an important alternative in the absence of measured solar radiation. However, due to the dynamic nature of atmosphere, accurate estimation of daily solar radiation has been being a challenging task. This paper presents an application of Support vector machine (SVM) to estimation of daily solar radiation using sunshine duration. Seven SVM models using different input attributes and five empirical sunshine-based models are evaluated using meteorological data at three stations in Liaoning province in China. All the SVM models give good performances and significantly outperform the empirical models. The newly developed model, SVM1 using sunshine ratio as input attribute, is preferred due to its greater accuracy and simple input attribute. It performs better in winter, while highest root mean square error and relative root mean square error are obtained in summer. The season-dependent SVM model is superior to the fixed model in estimation of daily solar radiation for winter, while consideration of seasonal variation of the data sets cannot improve the results for spring, summer and autumn. Moreover, daily solar radiation could be well estimated by SVM1 using the data from nearby stations. The results indicate that the SVM method would be a promising alternative over the traditional approaches for estimation of daily solar radiation

203

In Italy, West Nile virus (WNV) equine outbreaks have occurred annually since 2008. Characterizing WNV vector habitat requirements allows for the identification of areas at risk of viral amplification and transmission. Maxent-based ecological niche models were developed using literature records of 13 potential WNV Italian vector mosquito species to predict their habitat suitability range and to investigate possible geographical associations with WNV equine outbreak occurrence in Italy from 2008 to 2010. The contribution of different environmental variables to the niche models was also assessed. Suitable habitats for Culex pipiens, Aedes albopictus, and Anopheles maculipennis were widely distributed; Culex modestus, Ochlerotatus geniculatus, Ochlerotatus caspius, Coquillettidia richiardii, Aedes vexans, and Anopheles plumbeus were concentrated in north-central Italy; Aedes cinereus, Culex theileri, Ochlerotatus dorsalis, and Culiseta longiareolata were restricted to coastal/southern areas. Elevation, temperature, and precipitation variables showed the highest predictive power. Host population and landscape variables provided minor contributions. WNV equine outbreaks had a significantly higher probability to occur in habitats suitable for Cx. modestus and Cx. pipiens, providing circumstantial evidence that the potential distribution of these two species coincides geographically with the observed distribution of the disease in equines. PMID:24121802

Mughini-Gras, Lapo; Mulatti, Paolo; Severini, Francesco; Boccolini, Daniela; Romi, Roberto; Bongiorno, Gioia; Khoury, Cristina; Bianchi, Riccardo; Montarsi, Fabrizio; Patregnani, Tommaso; Bonfanti, Lebana; Rezza, Giovanni; Capelli, Gioia; Busani, Luca

2014-01-01

204

Energy Technology Data Exchange (ETDEWEB)

An axially symmetric radiation vector potential is derived for a spherically symmetric point source. This vector potential is used to derive a line integral for the solid angle subtended at a point source by a detector of arbitrary shape and location. An equivalent line integral given previously by Asvestas for optical applications is derived using this formulation. The line integral can be evaluated in closed form for important cases, and the analytical solution for the solid angle subtended by an ellipse at a general point is presented. The solution for the ellipse was obtained by considering sections of a right elliptic cone. The general solution for the ellipse requires the solution of an auxiliary cubic equation, but simpler formulas are possible for special cases. Numerical results both from the analytical formulas and direct numerical integration are given. The solution for the ellipse also provides exact solutions for the magnetic field of an elliptical current loop and the velocity field of a thin elliptical vortex. The well known solid angle formulas for a circular disk are also derived using this formulation.

Conway, John T., E-mail: John.Conway@uia.n [University of Agder, Grimstad (Norway)

2010-02-21

205

International Nuclear Information System (INIS)

The recently reported curl-free vector potential observation on the macro-scale, which has been attributed to a macro-scale matter wave associated with the quantum modulation of the de Broglie wave along the magnetic field, is seen to be in apparent contravention with the Lorentz equation of classical electrodynamics, which as a descriptor on the macro-scale takes no cognizance of a curl-free vector potential. The two different formalisms—a deterministic one à la Lorentz and a probabilistic one by the quantum modulation—both existing on the macro-scale and, though in apparent contravention, complement each other and are essential for a complete description of all phenomena relating to charged particle dynamics. The quantum modulations which arise in consequence of transition across Landau levels appear as ‘hole’ auto-excitations in the Lorentz trajectory involving internal inelastic scattering. This lends a new dimension to the Lorentz trajectory which, though on the classical macro-scale, acts like a ‘quantum resonator’ and can now exist in a number of self-excited states labelled by the Landau level interval involved in the excitation, and which are of quantum origin and on the macro-scale, with the quantum modulations being the excitations. (paper)

206

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Full Text Available Background: The East African region has experienced several Rift Valley fever (RVF outbreaks since the 1930s. The objective of this study was to identify distributions of potential disease vectors in relation to disease epidemics. Understanding disease vector potential distributions is a major concern for disease transmission dynamics. Methods: Diverse ecological niche modelling techniques have been developed for this purpose: we present a maximum entropy (Maxent approach for estimating distributions of potential RVF vectors in un-sampled areas in East Africa. We modelled the distribution of two species of mosquitoes (Aedes aegypti and Culex pipiens complex responsible for potential maintenance and amplification of the virus, respectively. Predicted distributions of environmentally suitable areas in East Africa were based on the presence-only occurrence data derived from our entomological study in Ngorongoro District in northern Tanzania. Results: Our model predicted potential suitable areas with high success rates of 90.9% for A. aegypti and 91.6% for C. pipiens complex. Model performance was statistically significantly better than random for both species. Most suitable sites for the two vectors were predicted in central and northwestern Tanzania with previous disease epidemics. Other important risk areas include western Lake Victoria, northern parts of Lake Malawi, and the Rift Valley region of Kenya. Conclusion: Findings from this study show distributions of vectors had biological and epidemiological significance in relation to disease outbreak hotspots, and hence provide guidance for the selection of sampling areas for RVF vectors during inter-epidemic periods.

Clement Nyamunura Mweya

2013-10-01

207

International Nuclear Information System (INIS)

Benchmark experiments for International Reactor Physics Benchmark Experiments (IRPhE) Project carried out at TCA, the temperature effects on reactivity were studied for light water moderated and reflected UO2 cores with/without soluble poisons. The buckling coefficient method using the measured critical water levels was proposed by Suzaki et al. The temperature dependence of buckling coefficient of reactivity and its variance by the core configurations of the benchmark experiments was investigated using SRAC and MVP calculations. From the calculations by SRAC as well as by MVP it is seen that the K-value can be taken as an average value only for each core with temperature changes which are considered as perturbation parameter. The difference between our calculations and benchmark results which uses constant K-value for all cores proves that the results depend on K-value and it play important role in defining reactivity effect using the water level worth method. (author)

208

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Full Text Available Abstract Background Anopheles plumbeus has been recognized as a minor vector for human malaria in Europe since the beginning of the 20th century. In recent years this tree hole breeding mosquito species appears to have exploited novel breeding sites, including large and organically rich man-made containers, with consequently larger mosquito populations in close vicinity to humans. This lead to investigate whether current populations of An. plumbeus would be able to efficiently transmit Plasmodium falciparum, the parasite responsible for the most deadly form of malaria. Methods Anopheles plumbeus immatures were collected from a liquid manure pit in Switzerland and transferred as adults to the CEPIA (Institut Pasteur, France where they were fed on P. falciparum gametocytes produced in vitro. Anopheles gambiae mosquitoes served as controls. Development of P. falciparum in both mosquito species was followed by microscopical detection of oocysts on mosquito midguts and by sporozoite detection in the head/thorax by PCR and microscopy. Results A total of 293 wild An. plumbeus females from four independent collections successfully fed through a membrane on blood containing P. falciparum gametocytes. Oocysts were observed in mosquito midguts and P. falciparum DNA was detected in head-thorax samples in all four experiments, demonstrating, on a large mosquito sample, that An. plumbeus is indeed receptive to P. falciparum NF54 and able to produce sporozoites. Importantly, the proportion of sporozoites-infected An. plumbeus was almost similar to that of An. gambiae (31 to 88% An. plumbeus versus 67 to 97% An. gambiae. However, the number of sporozoites produced was significantly lower in infected An. plumbeus. Conclusion The results show that a sample of field-caught An. plumbeus has a moderate to high receptivity towards P. falciparum. Considering the increased mobility of humans between Europe and malaria endemic countries and changes in environment and climate, these data strongly suggest that An. plumbeus could act as a vector for malaria and thus significantly contribute to increasing the malaria transmission risk in Central-Western Europe. In locations showing high vulnerability to the presence of gametocyte carriers, the risk of transmission of malaria by An. plumbeus should be considered.

Schaffner Francis

2012-11-01

209

Even with continuous vector control, dengue is still a growing threat to public health in Southeast Asia. Main causes comprise difficulties in identifying productive breeding sites and inappropriate targeted chemical interventions. In this region, rural families keep live birds in backyards and dengue mosquitoes have been reported in containers in the cages. To focus on this particular breeding site, we examined the capacity of bird fecal matter (BFM) from the spotted dove, to support Aedes albopictus larval growth. The impact of BFM larval uptake on some adult fitness traits influencing vectorial capacity was also investigated. In serial bioassays involving a high and low larval density (HD and LD), BFM and larval standard food (LSF) affected differently larval development. At HD, development was longer in the BFM environment. There were no appreciable mortality differences between the two treatments, which resulted in similar pupation and adult emergence successes. BFM treatment produced a better gender balance. There were comparable levels of blood uptake and egg production in BFM and LSF females at LD; that was not the case for the HD one, which resulted in bigger adults. BFM and LSF females displayed equivalent lifespans; in males, this parameter was shorter in those derived from the BFM/LD treatment. Taken together these results suggest that bird defecations successfully support the development of Ae. albopictus. Due to their cryptic aspects, containers used to supply water to encaged birds may not have been targeted by chemical interventions. PMID:25617636

Dieng, Hamady; Hassan, Rahimah Binti; Hassan, Ahmad Abu; Ghani, Idris Abd; Abang, Fatimah Bt; Satho, Tomomitsu; Miake, Fumio; Ahmad, Hamdan; Fukumitsu, Yuki; Hashim, Nur Aida; Zuharah, Wan Fatma; Kassim, Nur Faeza Abu; Majid, Abdul Hafiz Ab; Selvarajoo, Rekha; Nolasco-Hipolito, Cirilo; Ajibola, Olaide Olawunmi; Tuen, Andrew Alek

2015-05-01

210

Newtonian simulations are routinely used to examine the matter dynamics on non-linear scales. However, even on these scales, Newtonian gravity is not a complete description of gravitational effects. A post-Friedmann approach shows that the leading order correction to Newtonian theory is the existence of a vector potential in the metric. This vector potential can be calculated from N-body simulations, requiring a method for extracting the velocity field. Here, we present the full details of our calculation of the post-Friedmann vector potential, using the Delauney Tesselation Field Estimator (DTFE) code. We include a detailed examination of the robustness of our numerical result, including the effects of box size and mass resolution on the extracted fields. We present the power spectrum of the vector potential and find that the power spectrum of the vector potential is $\\sim 10^5$ times smaller than the power spectrum of the fully non-linear scalar gravitational potential at redshift zero. Comparing our numeri...

Thomas, Daniel B; Wands, David

2015-01-01

211

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Full Text Available Osteogenic potentials of some recombinant human bone morphogenetic protein (BMP first-generation adenoviral vectors (ADhBMPs are significantly limited in immunocompetent animals. It is unclear what role expression of viral proteins and foreign proteins transduced by adenoviral vectors play in the host immune response and in ectopic bone formation. In this study two sets of experiments were designed and performed. First, rat BMP6 cDNA were amplified, sequenced, and recombined in first-generation adenoviral vector (ADrBMP6. A comparison of human and rat BMP6 adenoviral vectors demonstrated identical osteogenic activities in both immunodeficient and immunocompetent rats. Second, the activities of recombinant human BMP6 in E1- (ADhBMP6 and [E1-,E2b-] ( [E1-,E2b-]ADGFP&hBMP6, and [E1-,E2b-]ADhBMP6 adenoviral vectors were compared in both in vitro and in vivo models. Similar activities of these two generations of BMP adenoviral vectors were found in all models. These results indicate that the amount of viral gene expression and the source of the BMP cDNA are not major factors in the interruption of osteogenic potentials of recombinant BMP6 adenoviral vectors in immunocompetent animals.

Hongwei Li, Jin Zhong Li, Debra D. Pittman, Andy Amalfitano, Gerald R. Hankins, Gregory A. Helm

2006-01-01

212

Bird species from the order Procellariiformes or petrels, including the northern fulmar (Fulmarus glacialis), produce high lipid and high energy content stomach oils from the prey they consume, which enables them to exploit distant marine food sources. Stomach oils are also used as a food source for chicks and for defensive purposes. Samples of stomach oils from two Arctic colonies, St. George Island Alaska, USA and Cape Vera, Devon Island Nunavut, Canada, were collected and analyzed for organochlorine contaminants. SigmaPCB concentrations ranged from 13 to 236 ng g(-1) wet weight (ww) and SigmaDDT concentrations from 5 to 158 ng g(-1) ww and were similar in both sites, though differences in chemical signatures were apparent. Stomach oils are a rich energy source; however, they may also provide a higher dose of contaminants per unit energy than the direct consumption of prey items, as illustrated using mass and energy balance calculations to estimate chick exposure to SigmaDDT for hypothetical stomach oil and whole prey diets. The results of this study suggest that stomach oils are an important vector of organochlorine contaminants to chicks and should be considered in future risk assessments of northern fulmars and other species of petrels. To our knowledge this is the first study of stomach oils as an overlooked vector of organochlorine contaminants to chicks and as a potentially valuable medium for dietary analysis and noninvasive biomonitoring both of petrel dietary exposure and of marine contaminant concentrations. PMID:20707316

Foster, Karen L; Wang, Shiway W; Mackay, Don; Mallory, Mark L; Blais, Jules M

2010-09-01

213

We investigate the asymptotic behaviour of a family of multiple orthogonal polynomials that is naturally linked with the normal matrix model with a monomial potential of arbitrary degree d + 1. The polynomials that we investigate are multiple orthogonal with respect to a system of d analytic weights defined on a symmetric (d + 1)-star centred at the origin. In the first part we analyse in detail a vector equilibrium problem involving a system of d interacting measures (?1, …, ?d) supported on star-like sets in the plane. We show that in the subcritical regime, the first component ?1* of the solution to this problem is the asymptotic zero distribution of the multiple orthogonal polynomials. It also characterizes the domain where the eigenvalues in the normal matrix model accumulate, in the sense that the Schwarz function associated with the boundary of this domain can be expressed explicitly in terms of ?1* . The second part of the paper is devoted to the asymptotic analysis of the multiple orthogonal polynomials. The asymptotic results are obtained again in the subcritical regime, and they follow from the Deift/Zhou steepest descent analysis of a Riemann–Hilbert problem of size (d + 1) × (d + 1). The vector equilibrium problem and the Riemann–Hilbert problem that we investigate are generalizations of those studied recently by Bleher–Kuijlaars in the case d = 2.

Kuijlaars, Arno B. J.; López-García, Abey

2015-02-01

214

Potential for Lyme disease in Maine: deer survey of distribution of Ixodes dammini, the tick vector.

A survey of deer brought to tagging stations at 24 sites in Main revealed the presence of the deer tick, Ixodes dammini, on 5.1 percent of deer. Ticks were found almost exclusively on deer from southwest coastal sites in the state. The potential for endemic Lyme disease in coastal Maine merits further study. PMID:2305920

Smith, R P; Rand, P W; Lacombe, E H

1990-03-01

215

International Nuclear Information System (INIS)

Several computer codes in the nuclear field have been vectorized, parallelized and transported on the FUJITSU VPP500 system, the AP3000 system and the Paragon system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 12 codes in fiscal 1998. These results are reported in 3 parts, i.e., the vectorization and parallelization on vector processors part, the parallelization on scalar processors part and the porting part. In this report, we describe the vectorization and parallelization on vector processors. In this vectorization and parallelization on vector processors part, the vectorization of General Tokamak Circuit Simulation Program code GTCSP, the vectorization and parallelization of Molecular Dynamics NTV (n-particle, Temperature and Velocity) Simulation code MSP2, Eddy Current Analysis code EDDYCAL, Thermal Analysis Code for Test of Passive Cooling System by HENDEL T2 code THANPACST2 and MHD Equilibrium code SELENEJ on the VPP500 are described. In the parallelization on scalar processors part, the parallelization of Monte Carlo N-Particle Transport code MCNP4B2, Plasma Hydrodynamics code using Cubic Interpolated Propagation Method PHCIP and Vectorized Monte Carlo code (continuous energy model / multi-group model) MVP/GMVP on the Paragon are described. In the porting part, the porting of Monte Carlo N-Particle Transport code MCNP4B2 and Reactor Safety Analysis code RELAP5 on the AP3000 are described. (author)

216

Energy Technology Data Exchange (ETDEWEB)

Several computer codes in the nuclear field have been vectorized, parallelized and transported on the FUJITSU VPP500 system, the AP3000 system and the Paragon system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 12 codes in fiscal 1998. These results are reported in 3 parts, i.e., the vectorization and parallelization on vector processors part, the parallelization on scalar processors part and the porting part. In this report, we describe the vectorization and parallelization on vector processors. In this vectorization and parallelization on vector processors part, the vectorization of General Tokamak Circuit Simulation Program code GTCSP, the vectorization and parallelization of Molecular Dynamics NTV (n-particle, Temperature and Velocity) Simulation code MSP2, Eddy Current Analysis code EDDYCAL, Thermal Analysis Code for Test of Passive Cooling System by HENDEL T2 code THANPACST2 and MHD Equilibrium code SELENEJ on the VPP500 are described. In the parallelization on scalar processors part, the parallelization of Monte Carlo N-Particle Transport code MCNP4B2, Plasma Hydrodynamics code using Cubic Interpolated Propagation Method PHCIP and Vectorized Monte Carlo code (continuous energy model / multi-group model) MVP/GMVP on the Paragon are described. In the porting part, the porting of Monte Carlo N-Particle Transport code MCNP4B2 and Reactor Safety Analysis code RELAP5 on the AP3000 are described. (author)

Ishizuki, Shigeru; Kawai, Wataru; Nemoto, Toshiyuki [Fujitsu Ltd., Tokyo (Japan); Ogasawara, Shinobu; Kume, Etsuo; Adachi, Masaaki; Kawasaki, Nobuo [Center for Promotion of Computational Science and Engineering (Tokai Site), Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan); Yatake, Yo-ichi [Hitachi Ltd., Tokyo (Japan)

2000-03-01

217

Full Core Burn-up Calculation at JRR-3 with MVP-BURN

International Nuclear Information System (INIS)

Research reactors use a burnable poison to suppress an excess reactivity in the beginning of reactor lifetime. The JRR-3 (Japan Research Reactor No.3) has used cadmium wires of radius 0.02 cm as a burnable poison. This report describes burn-up calculations of plate fuel models and full core models with MVP-BURN, which is a burn-up calculation code using Monte Carlo method and has been developed in JAEA (Japan Atomic Energy Agency). As the results of calculations of plate models, between a model composed of one burn-up region along the radius direction and a model composed of a few burn-up regions along the radius direction, the effective absorption cross section of 113Cd has had different tendency on reaching approximate 40. day (10000 MWd/t). And as results of calculations of full core model, it has been indicated that keff is almost same till approximate 80. day (22000 MWd/t) between a model composed of one burn-up region along the vertical direction and a model composed of a few burn-up regions along the vertical direction. However difference of 113Cd burn-up becomes pronounced and each keff makes a difference after 80. day. (authors)

218

International Nuclear Information System (INIS)

In order to investigate the impact of resonance elastic scattering models on the Doppler reactivity effect, the exact and the constant cross section models with the thermal motion of target nucleus were newly implemented into the MVP-2 continuous-energy Monte Carlo code with and without consideration of energy-dependent resonance cross section, respectively, and the UO2 pin-cell Doppler reactivity benchmark calculations were carried out with the modified code and the JENDL-3.3 library. The present study has revealed that the exact model gives more negative Doppler reactivity coefficients by 7-11% than the conventional asymptotic model, while the constant cross section model gives slightly less negative coefficients than the conventional asymptotic model. Furthermore, it has been found that the impact of resonance elastic scattering models is considerably large around the resonances where elastic scattering has relatively high contribution, whereas capture-dominant resonances have no significant impacts of the models on the Doppler reactivity coefficients. (author)

219

Criticality benchmarks with a continuous-energy Monte Carlo code MVP and JENDL-3.3

International Nuclear Information System (INIS)

Criticality benchmark testing of JENDL-3.3 was performed with MVP for many critical experiments in the ICSBEP Handbook: highly enriched uranium (HEU) and low enriched uranium (LEU) fueled solutions, LEU fueled water-moderated lattices, MOX fueled water-moderated lattices and metal fueled small assemblies with hard neutron spectra. The calculations with the preliminary U235 and U238 data for ENDF/B-VII (preVII) are also made for some benchmarks to confirm their performances and to compare with the JENDL-3.3 results. The prediction accuracy of criticality with JENDL-3.3 is satisfactory, within ±0.5%?k in most cases, except for slightly enriched uranium fueled lattices. The preVII data of U238 with lower thermal capture cross section improves the under prediction of keff for the slightly enriched lattices, while slight overestimations were observed for the LEU lattices whose U235 enrichment is more than 3wt.%. On the other hand, the preVII data gives excellent results for the metal fueled assemblies compared with JENDL-3.3. (author)

220

Three hemotropic mycoplasmas have been identified in pet cats: Mycoplasma haemofelis, “Candidatus Mycoplasma haemominutum,” and “Candidatus Mycoplasma turicensis.” The way in which these agents are transmitted is largely unknown. Thus, this study aimed to investigate fleas, ticks, and rodents as well as saliva and feces from infected cats for the presence of hemotropic mycoplasmas, to gain insight into potential transmission routes for these agents. DNA was extracted from arthropods a...

Willi, Barbara; Boretti, Felicitas S.; Meli, Marina L.; Bernasconi, Marco V.; Casati, Simona; Hegglin, Daniel; Puorger, Maria; Neimark, Harold; Cattori, Valentino; Wengi, Nicole; Reusch, Claudia E.; Lutz, Hans; Hofmann-lehmann, Regina

2007-01-01

221

Three hemotropic mycoplasmas have been identified in pet cats: Mycoplasma haemofelis, "Candidatus Mycoplasma haemominutum," and "Candidatus Mycoplasma turicensis." The way in which these agents are transmitted is largely unknown. Thus, this study aimed to investigate fleas, ticks, and rodents as well as saliva and feces from infected cats for the presence of hemotropic mycoplasmas, to gain insight into potential transmission routes for these agents. DNA was extracted from arthropods and from ...

Willi, B.; Boretti, F. S.; Meli, M. L.; Bernasconi, M. V.; Casati, S.; Hegglin, D.; Puorger, M.; Neimark, H.; Cattori, V.; Wengi, N.; Reusch, C. E.; Lutz, H.; Hofmann-lehmann, R.

2007-01-01

222

Gastrointestinal (GI) nematodes are among the most important causes of production loss in farmed ruminants, and anthelmintic resistance is emerging globally. We hypothesized that wild deer could potentially act as reservoirs of anthelmintic-resistant GI nematodes between livestock farms. Adult abomasal nematodes and faecal samples were collected from fallow (n = 24), red (n = 14) and roe deer (n = 10) from venison farms and areas of extensive or intensive livestock farming. Principal componen...

Chintoan-uta, C; Morgan, E. R.; Skuce, P. J.; Coles, G. C.

2014-01-01

223

Lactic acid bacteria-20 years exploring their potential as live vectors for mucosal vaccination.

Lactic acid bacteria (LAB) are a diverse group of Gram-positive, nonsporulating, low G?+?C content bacteria. Many of them have been given generally regarded as safe status. Over the past two decades, intensive genetic and molecular research carried out on LAB, mainly Lactococcus lactis and some species of the Lactobacillus genus, has revealed new, potential biomedical LAB applications, including the use of LAB as adjuvants, immunostimulators, or therapeutic drug delivery systems, or as factories to produce therapeutic molecules. LAB enable immunization via the mucosal route, which increases effectiveness against pathogens that use the mucosa as the major route of entry into the human body. In this review, we concentrate on the encouraging application of Lactococcus and Lactobacillus genera for the development of live mucosal vaccines. First, we present the progress that has recently been made in the field of developing tools for LAB genetic manipulations, which has resulted in the successful expression of many bacterial, parasitic, and viral antigens in LAB strains. Next, we discuss the factors influencing the efficacy of the constructed vaccine prototypes that have been tested in various animal models. Apart from the research focused on an application of live LABs as carriers of foreign antigens, a lot of work has been recently done on the potential usage of nonliving, nonrecombinant L. lactis designated as Gram-positive enhancer matrix (GEM), as a delivery system for mucosal vaccination. The advantages and disadvantages of both strategies are also presented. PMID:25750046

Wyszy?ska, Agnieszka; Kobierecka, Patrycja; Bardowski, Jacek; Jagusztyn-Krynicka, El?bieta Katarzyna

2015-04-01

224

Directory of Open Access Journals (Sweden)

Full Text Available Susceptibily experiments were carried out with a Biomphalaria straminea-like planorbid snail (Biomphalaria aff. straminea, species inquirenda from Espinillar, near Salto (Uruguay, in the area of the Salto Grande reservoir, exposed individually to 5 miracidia of Schistosoma mansoni (SJ2 and BH2 strains. Of 130 snails exposed to the SJ2 strain, originally infective to Biomphalaria tenagophila, 30 became infected (23%. The prepatent (precercaria period ranged from 35 to 65 days. The cercarial output was irregular, following no definite pattern, varying from 138 to 76,075 per snail (daily average 4.3 to 447.5 and ending up with death. Three specimens that died, without having shed cercarie, on days 69 (2 and 80 after exposure to miracidia, had developing secondary sporocysts in their tissues, justifying the prospect of a longer precercarial period in these cases. In a control group of 120 B. teangophila, exposed to the SJ2 strain, 40 became infected, showing an infection rate (33.3% not significantly different from that of the Espinillar snail (X [raised to the power of] 2 = 3.26. No cercarie were produced by any of the Espinilar snails exposed to miracidia of the BH2 strain, originally infective to Biomphalaria glabrata. Four specimens showed each a primary sporocyst in one tentacle, which disappeared between 15 and 25 days post-exposure, and two others died with immature, very slender sporocysts in their tissues on days 36 and 54. In a control group of 100 B. glabrata exposed to BH2 miracidia, 94 shed cercariae (94% and 6 remained negative. Calculation of Frandsen's (1979a, b TCP/100 index shows that "Espinillar Biomphalaria-SJ2 S. mansoni" is a vector-parasite "compatible" combination. Seeing that tenagophila-borne schistosomiasis is prevalent in Rio de Janeiro and São Paulo states and has recently spread sothwards to Santa Catarina state, and the range of B. tenagophila overlaps taht of the Espinillar Biomphalaria, the possibility of schistosomiais establishing itself in Uruguay, although not imminent, is not to be disregarded.Foram feitas provas de suscetibilidade com um molusco planorbídeo semelhante à Biomphalaria straminea (species inquirenda de Espinillar, localidade próxima a Salto (Uruguay, na área da represa de Salto Grande, cada exemplar sendo exposto individualmente a 5 miracídios de Schistosom mansoni (cepas SJ2 e BH2. De 130 exemplares expostos à cepa SJ2, originalmente infectante para B. tenagophila, 30 se infectaram (23%. O período pré-patente (pré-cercariano variou de 35 a 65 dias. A emissão de cercárias foi irregular, não seguindo padrão definido, variando de 138 a 76.075 por exemplar (média diária de 4,3 a 447,5 e teminando com a morte. Três exemplares que morreram, sem ter eliminado cercárias, no 69º (2 e no 80º dia após exposição aos miracídios, tinham esporocistos secundários em desenvolvimento nos tecidos, justificando a expectativa de um período pré-patente mais longo nestes casos. Em um grupo-controle de 120 B. tenagophila, exposta à cepa SJ2, 40 se infectaram, não diferindo significativamente seu índice de infecção (33.3% daquele do planorbídeo de Espinillar (X [ao quadrado]=3.26. De 100 exemplares de Espinillar expostos a miracídios da cepa BH2, originalmente infectante para B. glabrata, nenhum produziu cercárias. Um esporocisto primário formou-se em um tentáculo em 4 exemplares, desaparecendo entre 15 e 25 dias após a exposição. Dois outros exemplares morreram com esporocistos imaturos e muito delgados nos tecidos (4 em um caso e 3 no outro, no 36º e 54º dias. Em um grupo-controle de 100 B. glabrata exposto à cepa BH2, 94 emitiram cercárias (94% e 6 permaneceram negativos. De acordo com o índice TCP/100 de Frandsen (1979a,b, a combinação Biomphalaria de Espinillar-S. mansoni SJ2 constitui uma relação vetor-parasito "compatível". Tendo em vista que a xistosomose transmitida pela B. tenagophila é prevalente nos estados do Rio de Janeiro e São Paulo e recentemente propagou-se para o sul até o estado de Santa Catarina, e a dist

W. Lobato Paraense

1989-09-01

225

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Foram feitas provas de suscetibilidade com um molusco planorbídeo semelhante à Biomphalaria straminea (species inquirenda) de Espinillar, localidade próxima a Salto (Uruguay), na área da represa de Salto Grande, cada exemplar sendo exposto individualmente a 5 miracídios de Schistosom mansoni (cepas [...] SJ2 e BH2). De 130 exemplares expostos à cepa SJ2, originalmente infectante para B. tenagophila, 30 se infectaram (23%). O período pré-patente (pré-cercariano) variou de 35 a 65 dias. A emissão de cercárias foi irregular, não seguindo padrão definido, variando de 138 a 76.075 por exemplar (média diária de 4,3 a 447,5) e teminando com a morte. Três exemplares que morreram, sem ter eliminado cercárias, no 69º (2) e no 80º dia após exposição aos miracídios, tinham esporocistos secundários em desenvolvimento nos tecidos, justificando a expectativa de um período pré-patente mais longo nestes casos. Em um grupo-controle de 120 B. tenagophila, exposta à cepa SJ2, 40 se infectaram, não diferindo significativamente seu índice de infecção (33.3%) daquele do planorbídeo de Espinillar (X [ao quadrado]=3.26). De 100 exemplares de Espinillar expostos a miracídios da cepa BH2, originalmente infectante para B. glabrata, nenhum produziu cercárias. Um esporocisto primário formou-se em um tentáculo em 4 exemplares, desaparecendo entre 15 e 25 dias após a exposição. Dois outros exemplares morreram com esporocistos imaturos e muito delgados nos tecidos (4 em um caso e 3 no outro), no 36º e 54º dias. Em um grupo-controle de 100 B. glabrata exposto à cepa BH2, 94 emitiram cercárias (94%) e 6 permaneceram negativos. De acordo com o índice TCP/100 de Frandsen (1979a,b), a combinação Biomphalaria de Espinillar-S. mansoni SJ2 constitui uma relação vetor-parasito "compatível". Tendo em vista que a xistosomose transmitida pela B. tenagophila é prevalente nos estados do Rio de Janeiro e São Paulo e recentemente propagou-se para o sul até o estado de Santa Catarina, e a distribuição geográfica da B. tenagophila soprepõe-se à da Biomphalaria de Espinilar, a possibilidade do estabelecimento da xistosomose no Uruguai, ainda que não iminente, não deve ser desconsiderada. Abstract in english Susceptibily experiments were carried out with a Biomphalaria straminea-like planorbid snail (Biomphalaria aff. straminea, species inquirenda) from Espinillar, near Salto (Uruguay), in the area of the Salto Grande reservoir, exposed individually to 5 miracidia of Schistosoma mansoni (SJ2 and BH2 str [...] ains). Of 130 snails exposed to the SJ2 strain, originally infective to Biomphalaria tenagophila, 30 became infected (23%). The prepatent (precercaria) period ranged from 35 to 65 days. The cercarial output was irregular, following no definite pattern, varying from 138 to 76,075 per snail (daily average 4.3 to 447.5 and ending up with death. Three specimens that died, without having shed cercarie, on days 69 (2) and 80 after exposure to miracidia, had developing secondary sporocysts in their tissues, justifying the prospect of a longer precercarial period in these cases. In a control group of 120 B. teangophila, exposed to the SJ2 strain, 40 became infected, showing an infection rate (33.3%) not significantly different from that of the Espinillar snail (X [raised to the power of] 2 = 3.26). No cercarie were produced by any of the Espinilar snails exposed to miracidia of the BH2 strain, originally infective to Biomphalaria glabrata. Four specimens showed each a primary sporocyst in one tentacle, which disappeared between 15 and 25 days post-exposure, and two others died with immature, very slender sporocysts in their tissues on days 36 and 54. In a control group of 100 B. glabrata exposed to BH2 miracidia, 94 shed cercariae (94%) and 6 remained negative. Calculation of Frandsen's (1979a, b) TCP/100 index shows that "Espinillar Biomphalaria-SJ2 S. mansoni" is a vector-parasite "compatible" combination. Seeing that tenagophila-borne schi

W. Lobato, Paraense; Lygia R., Corrêa.

1989-09-01

226

Human filariasis and its vectors are little known in Ethiopia. Wuchereia bancrofti is confined to the western lowlands and cannot be the aetiological agent of elephantiasis in the highlands. Onchocerca volvulus is widespread in the south-western highlands. Loa loa and Dipetalonema perstans are reported here for the first time and appear to be uncommon. Studies were conducted in 1973, mostly near Jimma in Kaffa Province, on potential vectors of all but the first of these parasites. Among Simuliidae, the only blackflies of apparent medical importance were S. woodi ethiopiense and a possibly new member of the S. damnosum complex. The former is less seasonal and much less numerous than the latter, but may be more widespread and important along smaller and higher streams. Onchocerca larvae were recovered from "damnosum", but not from the small number (46) of ethiopiense examined. In August, at the height of the rainy season, the biting-rate of ethiopiense at 1,710 m altitude on the Gilgil Ghibe river reached 9.5/man-hour at 10-1100 hours and about 12/man-hour at 14-1600 hours. At the same time and place, the attack of "damnosum" reached a midday climax of about 1,800/man-hour; this peak could be delayed or suppressed by rain. Another possibly anthropophilic blackfly, S. dentulosum, tended to become most common in December afer the rainy season had passed, but proved incompetent to bite man successfully. The only feasible loiasis vector found in Ethiopia was Chrysops streptobalius; however, this tabanid was not closely associated with man. Up to 34/man-day were caught in watermeadows by the Gojeb river (altitude 1,160 m) in October. Man-biting species of Ceratopogonidae in various parts of Ethiopia were Culicoides fulvithorax, C. grahamii, C. kingi and C. milnei. The first two of these were anthropophilic in lowlands, but apparently not so in highlands. C. milnei was extremely abundant biting man highlands. C. milnei was extremely abundant biting man and domestic animals both indoors and outdg cycle was irregular, usually displaying a succession of ill-define nocturnal peaks; sometimes it attacked in daylight. Up to 35,000 C. milnei per trap-night were caught in light traps. Most of the females entering light traps in a stable were already engorged with blood. It seemed very likely that C. milnei would prove to be of veterinary importance. No firm indication was obtained as to what may transmit D. perstans in Ethiopia. PMID:877992

White, G B

1977-01-01

227

The endosymbiotic relationship could represent for many bacteria an important condition favouring their spread in the environment and in foods. For this purpose we studied the behaviour of some food-borne and opportunistic pathogens (Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, Salmonella enterica serovar Enteritidis, Aeromonas hydrophila, Yersinia enterocolitica) when internalized in Acanthamoeba polyphaga. Our results confirm the capability of the bacteria tested to grow within amoebal hosts. We can observe two types of interactions of the bacteria internalized in A. polyphaga. The first type, showed by Y. enterocolitica and A. hydrophila, was characterized by an early replication, probably followed by the killing and digestion of the bacteria. The second type, showed by E. faecalis and S. aureus was characterized by the persistence and grow inside the host without lysis. Lastly, when amoebae were co-cultured with L. monocytogenes and S. Enteritidis, an eclipse phase followed by an active intracellular growth was observed, suggesting a third type of predator-prey trend. The extracellular count in presence of A. polyphaga, as a result of an intracellular multiplication and subsequent release, was characterized by an increase of E. faecalis, S. aureus, L. monocytogenes and S. Enteritidis, and by a low or absent cell count for Y. enterocolitica and A. hydrophila. Our study suggests that the investigated food-borne and opportunistic pathogens are, in most cases, able to interact with A. polyphaga, to intracellularly replicate and, lastly, to be potentially spread in the environment, underlining the possible role of this protozoan in food contamination. PMID:21953544

Anacarso, Immacolata; de Niederhäusern, Simona; Messi, Patrizia; Guerrieri, Elisa; Iseppi, Ramona; Sabia, Carla; Bondi, Moreno

2012-06-01

228

Three hemotropic mycoplasmas have been identified in pet cats: Mycoplasma haemofelis, "Candidatus Mycoplasma haemominutum," and "Candidatus Mycoplasma turicensis." The way in which these agents are transmitted is largely unknown. Thus, this study aimed to investigate fleas, ticks, and rodents as well as saliva and feces from infected cats for the presence of hemotropic mycoplasmas, to gain insight into potential transmission routes for these agents. DNA was extracted from arthropods and from rodent blood or tissue samples from Switzerland and from salivary and fecal swabs from two experimentally infected and six naturally infected cats. All samples were analyzed with real-time PCR, and some positive samples were confirmed by sequencing. Feline hemotropic mycoplasmas were detected in cat fleas and in a few Ixodes sp. and Rhipicephalus sp. ticks collected from animals but not in ticks collected from vegetation or from rodent samples, although the latter were frequently Mycoplasma coccoides PCR positive. When shedding patterns of feline hemotropic mycoplasmas were investigated, "Ca. Mycoplasma turicensis" DNA was detected in saliva and feces at the early but not at the late phase of infection. M. haemofelis and "Ca. Mycoplasma haemominutum" DNA was not amplified from saliva and feces of naturally infected cats, despite high hemotropic mycoplasma blood loads. Our results suggest that besides an ostensibly indirect transmission by fleas, direct transmission through saliva and feces at the early phase of infection could play a role in the epizootiology of feline hemotropic mycoplasmas. Neither the investigated tick nor the rodent population seems to represent a major reservoir for feline hemotropic mycoplasmas in Switzerland. PMID:17468284

Willi, Barbara; Boretti, Felicitas S; Meli, Marina L; Bernasconi, Marco V; Casati, Simona; Hegglin, Daniel; Puorger, Maria; Neimark, Harold; Cattori, Valentino; Wengi, Nicole; Reusch, Claudia E; Lutz, Hans; Hofmann-Lehmann, Regina

2007-06-01

229

International Nuclear Information System (INIS)

Experimental data of VHTRC (Very High Temperature Reactor Critical Assembly) were analyzed using Monte Carlo code MVP (general purpose Monte Carlo code of neutron and photon transport calculations based on the continuous energy method). The calculation accuracy of the code was evaluated by the analysis for nuclear characteristics of a HTGR (high temperature gas-cooled reactor). The MVP code can analyze with a detailed three-dimensional core model with a few approximations. The HTGRs have following characteristics from view point of nuclear design : they have burnable poisons, many void holes, namely, the control insertion holes and so on. Taking account of these characteristics, multiplication factor at criticality, burnable poison worth, and void worth were evaluated. The maximum calculation errors were 0.8%?k, 7%, and 25% respectively, From these results, it can be concluded that the MVP code is able to be applied to the nuclear characteristics analysis of the HTGR like the High Temperature Engineering Test Reactor (HTTR). (author)

230

International Nuclear Information System (INIS)

Benchmark calculations were performed for critical experiments at FKBN-M facility in RFNC-VNIITF, Russia using JENDL-3.2 nuclear data library and continuous energy Monte-Carlo code MVP. The fissile materials were high-enriched uranium and plutonium. Polyethylene was used as moderator. The neutron spectrum was changed by changing the geometry. Calculation results by MVP showed some errors. Discussion was made by reaction rates and ? values obtained by MVP. It showed the possibility that cross sections of U-235 had different trend of error in fast and thermal energy region respectively. It also showed the possibility of some error of cross section of Pu-239 in high energy region. (author)

231

Multi-satellites normalization of the FengYun-2s visible detectors by the MVP method

After January 13, 2012, FY-2F had successfully launched, the total number of the in orbit operating FengYun-2 geostationary meteorological satellites reached three. For accurate and efficient application of multi-satellite observation data, the study of the multi-satellites normalization of the visible detector was urgent. The method required to be non-rely on the in orbit calibration. So as to validate the calibration results before and after the launch; calculate day updating surface bidirectional reflectance distribution function (BRDF); at the same time track the long-term decay phenomenon of the detector's linearity and responsivity. By research of the typical BRDF model, the normalization method was designed. Which could effectively solute the interference of surface directional reflectance characteristics, non-rely on visible detector in orbit calibration. That was the Median Vertical Plane (MVP) method. The MVP method was based on the symmetry of principal plane, which were the directional reflective properties of the general surface targets. Two geostationary satellites were taken as the endpoint of a segment, targets on the intersecting line of the segment's MVP and the earth surface could be used as a normalization reference target (NRT). Observation on the NRT by two satellites at the moment the sun passing through the MVP brought the same observation zenith, solar zenith, and opposite relative direction angle. At that time, the linear regression coefficients of the satellite output data were the required normalization coefficients. The normalization coefficients between FY-2D, FY-2E and FY-2F were calculated, and the self-test method of the normalized results was designed and realized. The results showed the differences of the responsivity between satellites could up to 10.1%(FY-2E to FY-2F); the differences of the output reflectance calculated by the broadcast calibration look-up table could up to 21.1%(FY-2D to FY-2F); the differences of the output reflectance from FY-2D and FY-2E calculated by the site experiment results reduced to 2.9%(13.6% when using the broadcast table). The normalized relative error was also calculated by the self-test method, which was less than 0.2%.

Li, Yuan; Rong, Zhi-guo; Zhang, Li-jun; Sun, Ling; Xu, Na

2013-08-01

232

International Nuclear Information System (INIS)

Lattice cell calculations for VVR-M2 fuel assemblies of DaLat Nuclear Research reactor were performed using Monte Carlo code MVP. The physical parameters like infinite multiplication factors, few group constants, neutron flux distributions and temperature effects were investigated for both HEU and LEU configurations. The infinite multiplication factor and thermal neutron flux for LEU fuel are lower than HEU one. In order to effectively use Monte Carlo codes the high performance computing with cluster technique is proposed for large problems. (author)

233

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Full Text Available Una enfermedad que afecta severamente el rendimiento del cultivo de maíz es conocida como mal de Río Cuarto. El vector más importante es Delphacodes kuscheli. Este trabajo tuvo como objetivo determinar la capacidad vectora de una nueva especie, Tagosodes orizicolus, en campo y bajo condiciones experimentales. Los ensayos de transmisión se realizaron con ambas especies simultáneamente. Para la adquisición, latencia e infección se utilizaron los tiempos considerados óptimos para D. kuscheli. Las plantas fueron analizadas por DAS-ELISA. Se observaron glándulas salivales de T. orizicolus por microscopía electrónica. En las pruebas experimentales se obtuvieron porcentajes de transmisión del 10% para T. orizicolus y 42% para D. kuscheli. Los cortes ultrafinos de las glándulas salivales de T. orizicolus evidenciaron agregados de partículas virales de 70 nm de diámetro. No pudo comprobarse la capacidad vectora en condiciones naturales a partir de ensayos realizados con insectos capturados en campo. Asimismo, se mencionan por primera vez el trigo, la cebada y el triticale como cultivos adecuados para la cría de T. orizicolus. Estos resultados señalan a T. orizicolus como una especie de interés epidemiológico en el Noreste de Argentina, por la capacidad demostrada de adquirir y trasmitir en condiciones experimentales dicho agente viral.An important disease affecting the yield of corn crops is known as mal de Río Cuarto. Delphacodes kuscheli is the most important vector. The objective of this work was to determine the vector capacity of a new species, Tagosodes orizicolus, both in the field and under experimental conditions. Transmission trials were carried out on both species simultaneously. For acquisition, latency and infection the times considered optimum for D. kuscheli were used. The plants were analyzed by DAS-ELISA. Salivary glands of T. orizicolus were observed by electron microscopy. In experimental tests, values of percentages of transmission of 10% for T. orizicolus and 42% for D. kuscheli were obtained. The ultra-fine sections of the salivary glands of T. orizicolus showed the aggregation of viral particles 70 nm in diameter. Vectoral capacity could not be proven under natural conditions from a test conducted with insects captured in the field. Likewise, for the first time wheat, barley and triticale are mentioned as suitable crops for breeding T. orizicolus. These results show T. orizicolus to be a species of epidemiological interest in the northeast of Argentina due to the proven capacity of acquiring and transmitting this viral agent under experimental conditions.

María Fernanda Mattio

2008-06-01

234

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Spanish Abstract in spanish Una enfermedad que afecta severamente el rendimiento del cultivo de maíz es conocida como mal de Río Cuarto. El vector más importante es Delphacodes kuscheli. Este trabajo tuvo como objetivo determinar la capacidad vectora de una nueva especie, Tagosodes orizicolus, en campo y bajo condiciones exper [...] imentales. Los ensayos de transmisión se realizaron con ambas especies simultáneamente. Para la adquisición, latencia e infección se utilizaron los tiempos considerados óptimos para D. kuscheli. Las plantas fueron analizadas por DAS-ELISA. Se observaron glándulas salivales de T. orizicolus por microscopía electrónica. En las pruebas experimentales se obtuvieron porcentajes de transmisión del 10% para T. orizicolus y 42% para D. kuscheli. Los cortes ultrafinos de las glándulas salivales de T. orizicolus evidenciaron agregados de partículas virales de 70 nm de diámetro. No pudo comprobarse la capacidad vectora en condiciones naturales a partir de ensayos realizados con insectos capturados en campo. Asimismo, se mencionan por primera vez el trigo, la cebada y el triticale como cultivos adecuados para la cría de T. orizicolus. Estos resultados señalan a T. orizicolus como una especie de interés epidemiológico en el Noreste de Argentina, por la capacidad demostrada de adquirir y trasmitir en condiciones experimentales dicho agente viral. Abstract in english An important disease affecting the yield of corn crops is known as mal de Río Cuarto. Delphacodes kuscheli is the most important vector. The objective of this work was to determine the vector capacity of a new species, Tagosodes orizicolus, both in the field and under experimental conditions. Transm [...] ission trials were carried out on both species simultaneously. For acquisition, latency and infection the times considered optimum for D. kuscheli were used. The plants were analyzed by DAS-ELISA. Salivary glands of T. orizicolus were observed by electron microscopy. In experimental tests, values of percentages of transmission of 10% for T. orizicolus and 42% for D. kuscheli were obtained. The ultra-fine sections of the salivary glands of T. orizicolus showed the aggregation of viral particles 70 nm in diameter. Vectoral capacity could not be proven under natural conditions from a test conducted with insects captured in the field. Likewise, for the first time wheat, barley and triticale are mentioned as suitable crops for breeding T. orizicolus. These results show T. orizicolus to be a species of epidemiological interest in the northeast of Argentina due to the proven capacity of acquiring and transmitting this viral agent under experimental conditions.

María Fernanda, Mattio; Agustina, Cassol; Ana Marino de, Remes Lenicov; Graciela, Truol.

2008-06-01

235

International Nuclear Information System (INIS)

Using the momentum space representation, we solve the Klein–Gordon equation in one spatial dimension for the case of mixed scalar and vector linear potentials in the context of deformed quantum mechanics characterized by a finite minimal uncertainty in position. The expressions of bound state energies and the associated wave functions are exactly obtained. (general)

236

Directory of Open Access Journals (Sweden)

Full Text Available Mannose polyethylenimine with a molecular weight of 25 k (Man-PEI25k was synthesized via a phenylisothiocyanate bridge using mannopyranosylphenyl isothiocyanate as a coupling reagent, and characterized by 1H NMR (nuclear magnetic resonance and FT-IR (Fourier transform infrared spectroscopy analysis. Spherical nanoparticles were formed with diameters of 80–250 nm when the copolymer was mixed with DNA at various charge ratios of copolymer/DNA (N/P. Gel electrophoresis demonstrated that the DNA had been condensed and retained by the PEI derivates at low N/P ratios. The Man-PEI25k/DNA complexes were less cytotoxic than the PEI complexes with a molecular weight of 25 k (PEI25k at the same N/P ratio. Laser scan confocal microscopy and flow cytometry confirmed that the Man-PEI25k/DNA complexes gave higher cell uptake efficiency in (Dendritic cells DC2.4 cells than HeLa cells. The transfection efficiency of Man-PEI25k was higher than that of PEI25k towards DC2.4 cells. These results indicated that Man-PEI25k could be used as a potential DC-targeting non-viral vector for gene therapy.

Ying Hu

2014-10-01

237

To identify the host range of potential vectors of Dirofilaria immitis Leidy, the causal agent of canine dirofilariasis, we studied the bloodmeal origin of mosquitoes trapped on two of the Canary Islands, Gran Canaria and Tenerife, where this disease is considered hyperendemic. On Gran Canaria, mosquitoes were captured using Centers for Disease Control and Prevention (CDC) traps (outdoors) and resting in a bathroom (indoors). Only CDC traps were used to capture mosquitoes in Tenerife. The species captured in decreasing order of abundance were Culex theileri Theobald, Culex pipiens L., Culiseta longiareolata Macquart, Anopheles atroparvus van Thiel, and Anopheles cinereus Theobald. The origins of bloodmeals were identified for 121 Cx. theileri and 4 Cx. pipiens after amplification and sequencing of a fragment of the vertebrate cytochrome oxidase I (COI) gene. Cx. theileri fed on goats, sheep, dogs, cattle, cats, humans, and chickens, and Cx. pipiens fed on goats and chickens. A lower success of bloodmeal identification was obtained in mosquitoes captured resting indoors than outdoors in CDC traps, probably because of a longer time period between feeding and capture. Although most Cx. theileri fed on ruminants, this species also fed on different mammal species susceptible to dirofiliarasis, including humans, suggesting it could play a role on parasite transmission. PMID:23270171

Martínez-De La Puente, Josué; Moreno-Indias, Isabel; Hernández-Castellano, Lorenzo Enrique; Argüello, Anastasio; Ruiz, Santiago; Soriguer, Ramón; Figuerola, Jordi

2012-11-01

238

We investigate properties of strange quark matter in the framework of the SU(3) Nambu-Jona-Lasinio model with vector interactions under strong magnetic fields. The effects of vector-isoscalar and vector-isovector interactions on the equation of state of strange quark matter are investigated, and it is found that the equation of state is not sensitive to the vector-isovector interaction; however, a repulsive interaction in the vector-isoscalar channel gives a stiffer equation of state for cold dense quark matter. In the presence of a magnetic field, gluons will be magnetized via quark loops, and the contribution from magnetized gluons to the equation of state is also estimated. The sound velocity square is a quantity to measure the hardness or softness of dense quark matter, and in the Nambu-Jona-Lasinio model without vector interaction at zero magnetic field, the sound velocity square is always less than 1 /3 . It is found that a repulsive vector-isoscalar interaction and a positive pressure contribution from magnetized gluons can enhance the sound velocity square, which can even reach 1. To construct quark magnetars under strong magnetic fields, we consider anisotropic pressures and use a density-dependent magnetic field profile to mimic the magnetic field distribution in a quark star. We also analyze the parameter region for the magnitude of vector-isoscalar interaction and the contribution from magnetized gluons in order to produce two-solar-mass quark magnetars.

Chu, Peng-Cheng; Wang, Xin; Chen, Lie-Wen; Huang, Mei

2015-01-01

239

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background In the Veneto region (north-eastern Italy an entomological surveillance system has been implemented since the introduction of the Asian tiger mosquito (Aedes albopictus in 1991. During the routine monitoring activity in a tiger mosquito-free area, an unexpected mosquito was noticed, which clearly did not belong to the recorded Italian fauna. Findings At the end of May 2011, twelve larvae and pupae were collected in a small village in Belluno province (Veneto region from a single manhole. Ten adults reared in the laboratory were morphologically and genetically identified as Aedes (Finlaya koreicus (Edwards, 1917, a species native to Southeast Asia. The subsequent investigations carried out in the following months in the same village provided evidence that this species had become established locally. Entomological and epidemiological investigations are currently ongoing in the surrounding area, to verify the eventual extension of the species outside the village and to trace back the route of entry into Italy. Conclusions This is the first report in Italy of the introduction of the exotic mosquito Ae. koreicus. This species has been shown experimentally to be competent in the transmission of the Japanese encephalitis virus and of the dog heartworm Dirofilaria immitis and is considered a potential vector of other arboviruses. Thus, the establishment of this species may increase the current risk or pose new potential threats, for human and animal health. This finding considerably complicates the entomological monitoring of the Asian tiger mosquito Ae. albopictus in Italy and stresses the importance of implementing the entomological surveillance for the early detection of and the rapid response against invasive mosquito species.

Capelli Gioia

2011-09-01

240

Scientific Electronic Library Online (English)

Full Text Available Se registran por primera vez en el Ecuador dos especies de mosquitos (Diptera: Culicidae), vectores potenciales de los virus de la Fiebre Amarilla y Mayaro. Sabethes amazonicus Gordon and Evans y Haemagogus anastasionis Dyar fueron colectados en fase adulta en una localidad de la provincia de Zamora [...] -Chinchipe, en la cual se han presentado casos de Fiebre Amarilla selvática con anterioridad. Este hallazgo muestra la importancia de profundizar los estudios de linea base de vectores en el país, distribución geográfica y aspectos ecológicos y su posible relación epidemiológica con enfermedades emergentes y re-emergentes. Abstract in english Two new records of mosquitoes (Diptera: Culicidae) are presented from Ecuador, and both potential vectors of yellow fever virus and Mayaro. Sabethes amazonicus Gordon and Evans and Haemagogus anastasionis Dyar adults were collected in a locality in the province of Zamora-Chinchipe, in which there ha [...] ve been cases of yellow fever previously. This finding shows the importance of further studies of baseline vector in the country, geographical distribution and ecological aspects and possible epidemiological link with emerging and re-emerging diseases.

Navarro, Juan Carlos; Patricio, Ponce; Varsovia, Cevallos.

2013-01-01

241

Analysis of void coefficient in fast spectrum BWR core with Monte Carlo code 'MVP'

International Nuclear Information System (INIS)

An innovative large BWR core concept has been proposed for aiming at fuel breeding as well as negative void reactivity coefficient. The core consists of two types of MOX fuel assemblies. One is a triangular tight lattice bundle 1.6 m in active core height and the other is the same bundle 0.8 m. The ratio of flow area to fuel area of the bundle is set at about 0.5 in order to increase breeding ratio. A neutron-streaming channel that consists of a cavity-can containing helium gas and a flow gap between the cavity-can and the channel box is located above each short bundle. It will decrease void reactivity coefficient by enhancing neutron leakage from the core when the void fraction is increased in the flow gap. A core composed of tight lattice bundles provides a much harder neutron spectrum than that of conventional BWRs but a slightly softer one than that of typical FBRs. The cavity-can and the flow gap will cause a steep gradient of neutron flux. The neutronics for such a complicated core structure could not be properly analyzed by conventional analysis methods. In particular, the analysis of void reactivity coefficient requires a sophisticated method because it deals with a small change in core composition. In the analysis of the void reactivity coefficient, we adopted a three-dimensional Monte Carlo code 'MVP', which has been developed by JAERI and has many advantages such as an easy input form for lattice structures, a short run time and a continuous neutron energy run time and a continuous neutron energy method. The continuous neutron energy method is important for the analysis of this core because fission reactions occur mainly in the resonance energy region, where the evaluation of accurate cross sections is difficult with conventional methods. The library used is JENDL-3.2. The multi-layer structure of lattices is also essential for the analysis because its hard spectrum and relatively long neutron mean free path require a modeling for the full core with a lot of bundles. The analysis indicates that the void reactivity coefficient depends on flow gap width of the streaming channel and has a minimum value of about -2x10-4 ?k/k/%void, which is evaluated within an accuracy of about +-0.6x10-4 ?k/k/%void. The CPU time for one million histories calculating the full core model was about five hours with a PENTIUM-2 processor personal computer. (author)

242

International Nuclear Information System (INIS)

Considering the importance of thorium data and concerning about the accuracy of Th-232 cross section library, a series of experiments of thorium critical core carried out at KUCA facility of Kyoto Univ. Research Reactor Inst. have been analyzed. The core was composed of pure thorium plates and 93% enriched uranium plates, solid polyethylene moderator with hydro to U-235 ratio of 140 and Th-232 to U-235 ratio of 15.2. Calculations of the effective multiplication factor, control rod worth, reactivity worth of Th plates have been conducted by MVP code using JENDL-4.0 library [1]. At the experiment site, after achieving the critical state with 51 fuel rods inserted inside the reactor, the measurements of the reactivity worth of control rod and thorium sample are carried out. By comparing with the experimental data, the calculation overestimates the effective multiplication factor about 0.90%. Reactivity worth of the control rods evaluation using MVP is acceptable with the maximum discrepancy about the statistical error of the measured data. The calculated results agree to the measurement ones within the difference range of 3.1% for the reactivity worth of one Th plate. From this investigation, further experiments and research on Th-232 cross section library need to be conducted to provide more reliable data for thorium based fuel core design and safety calculation. (authors)

243

Energy Technology Data Exchange (ETDEWEB)

Considering the importance of thorium data and concerning about the accuracy of Th-232 cross section library, a series of experiments of thorium critical core carried out at KUCA facility of Kyoto Univ. Research Reactor Inst. have been analyzed. The core was composed of pure thorium plates and 93% enriched uranium plates, solid polyethylene moderator with hydro to U-235 ratio of 140 and Th-232 to U-235 ratio of 15.2. Calculations of the effective multiplication factor, control rod worth, reactivity worth of Th plates have been conducted by MVP code using JENDL-4.0 library [1]. At the experiment site, after achieving the critical state with 51 fuel rods inserted inside the reactor, the measurements of the reactivity worth of control rod and thorium sample are carried out. By comparing with the experimental data, the calculation overestimates the effective multiplication factor about 0.90%. Reactivity worth of the control rods evaluation using MVP is acceptable with the maximum discrepancy about the statistical error of the measured data. The calculated results agree to the measurement ones within the difference range of 3.1% for the reactivity worth of one Th plate. From this investigation, further experiments and research on Th-232 cross section library need to be conducted to provide more reliable data for thorium based fuel core design and safety calculation. (authors)

Mai, V. T.; Fujii, T.; Wada, K.; Kitada, T. [Osaka Univ., 2-1, Yamadaoka, Suita-shi, Osaka 565-0871 (Japan); Takaki, N.; Yamaguchi, A.; Watanabe, H. [Tokai Univ., 4-1-1 Kitakaname, Hiratsuka-shi, Kanagawa, 259-1292 (Japan); Unesaki, H. [Kyoto Univ. Research Reactor Inst., Asahiro-nishi, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan)

2012-07-01

244

International Nuclear Information System (INIS)

The sorption of ruthenium chlorocomplexes is studied on graft copolymer of polyacrylonitrile fibre with poly-2-methyl-5-vinylpyridine (PAN-MVP). The sorption has been performed under static conditions in the course of mixing at 20 and 98 deg from 0.1-2 OM HCl, 0.1-1 m NaCl solutions. The volume of the investigated solutions constituted 25 ml, fibre weight -0.1-0.3 g. Ruthenium concentration in solutions has been changed in the limits of 5x103-2x10-2 mol/l. The fibre has been preliminarily moistened by a solution containing no ruthenium. In all cases fresh-prepared ruthenium chlorocomplex solutions have been used. It has been found that with temperature increase the PAN-MVP sorption capacitance relative to ruthenium increases (at 20 deg-1.15 mmol/g, at 98 deg-1.70 mmol/g. The ruthenium chlorocomplex sorption by pyridine fibrous sorbent from salt-acid solutions occurs by anionoexchange mechanism and is related to the formation in the sorbent phase of onium chlorocomplexes - (RPyH)2 [RuCl6]. In the course of sorbents heating pyridine compounds are subject to Anderson regroupping with formation of compounds of diamine type-[Ru(RPy)2Cl4

245

Triatoma maculata is a wild vector of Trypanosoma cruzi, the causative agent of Chagas disease; its incursion in the domestic habitat is scant. In order to establish the possible domestic habitat of T. maculata, we evaluated wing variability and polymorphism of genotypic markers in subpopulations of T. maculata that live in different habitats in Venezuela. As markers, we used the mtCyt b gene, previously apply to evaluate population genetic structure in triatomine species, and the ?-tubulin gene region, a marker employed to study genetic variability in Leishmania subgenera. Adults of T. maculata were captured in the period 2012-2013 at domestic, peridomestic (PD), and wild areas of towns in the Venezuelan states of Anzoátegui, Bolívar, Portuguesa, Monagas, Nueva Esparta, and Sucre. The phenotypic analysis was conducted through the determination of the isometric size and conformation of the left wing of each insect (492 individuals), using the MorphoJ program. Results reveal that insects of the domestic habitat showed significant reductions in wing size and variations in anatomical characteristics associated with flying, in relation to the PD and wild habitats. The largest variability was found in Anzoátegui and Monagas. The genotypic variability was assessed by in silico sequence comparison of the molecular markers and PCR-RFLP assays, demonstrating a marked polymorphism for the markers in insects of the domestic habitat in comparison with the other habitats. The highest polymorphism was found for the ?-tubulin marker with enzymes BamHI and KpnI. Additionally, the infection rate by T. cruzi was higher in Monagas and Sucre (26.8 and 37.0%, respectively), while in domestic habitats the infestation rate was highest in Anzoátegui (22.3%). Results suggest domestic habitat colonization by T. maculata that in epidemiological terms, coupled with the presence in this habitat of nymphs of the vector, represents a high risk of transmission of Chagas disease. PMID:25325053

García-Alzate, Roberto; Lozano-Arias, Daisy; Reyes-Lugo, Rafael Matías; Morocoima, Antonio; Herrera, Leidi; Mendoza-León, Alexis

2014-01-01

246

Risk assessments of clinical applications involving genetically modified viral vectors are carried out according to general principles that are implemented in many national and regional legislations, e.g., in Directive 2001/18/EC of the European Union. Recent developments in vector design have a large impact on the concepts that underpin the risk assessments of viral vectors that are used in clinical trials. The use of (conditionally) replication competent viral vectors (RCVVs) may increase the likelihood of the exposure of the environment around the patient, compared to replication defective viral vectors. Based on this assumption we have developed a methodology for the environmental risk assessment of replication competent viral vectors, which is presented in this review. Furthermore, the increased likelihood of exposure leads to a reevaluation of what would constitute a hazardous gene product in viral vector therapies, and a keen interest in new developments in the inserts used. One of the trends is the use of inserts produced by synthetic biology. In this review the implications of these developments for the environmental risk assessment of RCVVs are highlighted, with examples from current clinical trials. The conclusion is drawn that RCVVs, notwithstanding their replication competency, can be applied in an environmentally safe way, in particular if adequate built-in safeties are incorporated, like conditional replication competency, as mitigating factors to reduce adverse environmental effects that could occur. PMID:24397527

van den Akker, Eric; van der Vlugt, Cecile J B; Bleijs, Diederik A; Bergmans, Hans E

2013-12-01

247

We investigate properties of strange quark matter in the framework of SU(3) Nambu--Jona-Lasinio(NJL) model with vector interaction under strong magnetic fields. The effects of vector-isoscalar and vector-isovector interaction on the equation of state of strange quark matter are investigated, and it is found that the equation of state is not sensitive to the vector-isovector interaction, however, a repulsive interaction in the vector-isoscalar channel gives a stiffer equation of state for cold dense quark matter. In the presence of magnetic field, gluons will be magnetized via quark loops, and the contribution from magnetized gluons to the equation of state is also estimated. The sound velocity square is a quantity to measure the hardness or softness of dense quark matter, and in the NJL model without vector interaction at zero magnetic field the sound velocity square is always less than 1/3. It is found that a repulsive vector-isoscalar interaction and a positive pressure contribution from magnetized gluons c...

Chu, Peng-Cheng; Chen, Lie-Wen; Huang, Mei

2014-01-01

248

International Nuclear Information System (INIS)

We have constructed a lentiviral vector with expression limited to cells presenting active E2F-1 protein, a potential advantage for gene therapy of proliferative diseases. For the FE2FLW vector, the promoter region of the human E2F-1 gene was utilized to drive expression of luciferase cDNA, included as a reporter of viral expression. Primary, immortalized, and transformed cells were transduced with the FE2FLW vector and cell cycle alterations were induced with serum starvation/replacement, contact inhibition or drug treatment, revealing cell cycle-dependent changes in reporter activity. Forced E2F-1 expression, but not E2F-2 or E2F-3, increased reporter activity, indicating a major role for this factor in controlling expression from the FE2FLW virus. We show the utility of this vector as a reporter of E2F-1 and proliferation-dependent cellular alterations upon cytotoxic/cytostatic treatment, such as the introduction of tumor suppressor genes. We propose that the FE2FLW vector may be a starting point for the development of gene therapy strategies for proliferative diseases, such as cancer or restinosis

249

Background Rift Valley fever (RVF) is a mosquito-borne viral zoonosis that primarily affects ruminants but also has the capacity to infect humans. Objective To determine the abundance and distribution of mosquito vectors in relation to their potential role in the virus transmission and maintenance in disease epidemic areas of Ngorongoro district in northern Tanzania. Methods A cross-sectional entomological investigation was carried out before the suspected RVF outbreak in October 2012. Mosquitoes were sampled both outdoors and indoors using the Centre for Disease Control (CDC) light traps and Mosquito Magnets baited with attractants. Outdoor traps were placed in proximity with breeding sites and under canopy in banana plantations close to the sleeping places of animals. Results A total of 1,823 mosquitoes were collected, of which 87% (N=1,588) were Culex pipiens complex, 12% (N=226) Aedes aegypti, and 0.5% (N=9) Anopheles species. About two-thirds (67%; N=1,095) of C. pipiens complex and nearly 100% (N=225) of A. aegypti were trapped outdoors using Mosquito Magnets. All Anopheles species were trapped indoors using CDC light traps. There were variations in abundance of C. pipiens complex and A. aegypti among different ecological and vegetation habitats. Over three quarters (78%) of C. pipiens complex and most (85%) of the A. aegypti were trapped in banana and maize farms. Both C. pipiens complex and A. aegypti were more abundant in proximity with cattle and in semi-arid thorn bushes and lower Afro-montane. The highest number of mosquitoes was recorded in villages that were most affected during the RVF epidemic of 2007. Of the tested 150 pools of C. pipiens complex and 45 pools of A. aegypti, none was infected with RVF virus. Conclusions These results provide insights into unique habitat characterisation relating to mosquito abundances and distribution in RVF epidemic-prone areas of Ngorongoro district in northern Tanzania. PMID:25613346

Mweya, Clement N.; Kimera, Sharadhuli I.; Mellau, Lesakit S. B.; Mboera, Leonard E. G.

2015-01-01

250

Since the 1990s, possibly earlier, large numbers of Asian swamp eels (Synbranchidae: Monopterus spp.), some wild-caught, have been imported live from various countries in Asia and sold in ethnic food markets in cities throughout the USA and parts of Canada. Such markets are the likely introduction pathway of some, perhaps most, of the five known wild populations of Asian swamp eels present in the continental United States. This paper presents results of a pilot study intended to gather baseline data on the occurrence and abundance of internal macroparasites infecting swamp eels imported from Asia to North American retail food markets. These data are important in assessing the potential role that imported swamp eels may play as possible vectors of non-native parasites. Examination of the gastrointestinal tracts and associated tissues of 19 adult-sized swamp eels—identified as M. albus "Clade C"—imported from Vietnam and present in a U.S. retail food market revealed that 18 (95%) contained macroparasites. The 394 individual parasites recovered included a mix of nematodes, acanthocephalans, cestodes, digeneans, and pentastomes. The findings raise concern because of the likelihood that some parasites infecting market swamp eels imported from Asia are themselves Asian taxa, some possibly new to North America. The ecological risk is exacerbated because swamp eels sold in food markets are occasionally retained live by customers and a few reportedly released into the wild. For comparative purposes, M. albus "Clade C" swamp eels from a non-native population in Florida (USA) were also examined and most (84%) were found to be infected with internal macroparasites. The current level of analysis does not allow us to confirm whether these are non-native parasites.

Nico, Leo G.; Sharp, Paul; Collins, Timothy M.

2011-01-01

251

Directory of Open Access Journals (Sweden)

Full Text Available Background: Rift Valley fever (RVF is a mosquito-borne viral zoonosis that primarily affects ruminants but also has the capacity to infect humans. Objective: To determine the abundance and distribution of mosquito vectors in relation to their potential role in the virus transmission and maintenance in disease epidemic areas of Ngorongoro district in northern Tanzania. Methods: A cross-sectional entomological investigation was carried out before the suspected RVF outbreak in October 2012. Mosquitoes were sampled both outdoors and indoors using the Centre for Disease Control (CDC light traps and Mosquito Magnets baited with attractants. Outdoor traps were placed in proximity with breeding sites and under canopy in banana plantations close to the sleeping places of animals. Results: A total of 1,823 mosquitoes were collected, of which 87% (N=1,588 were Culex pipiens complex, 12% (N=226 Aedes aegypti, and 0.5% (N=9 Anopheles species. About two-thirds (67%; N=1,095 of C. pipiens complex and nearly 100% (N=225 of A. aegypti were trapped outdoors using Mosquito Magnets. All Anopheles species were trapped indoors using CDC light traps. There were variations in abundance of C. pipiens complex and A. aegypti among different ecological and vegetation habitats. Over three quarters (78% of C. pipiens complex and most (85% of the A. aegypti were trapped in banana and maize farms. Both C. pipiens complex and A. aegypti were more abundant in proximity with cattle and in semi-arid thorn bushes and lower Afro-montane. The highest number of mosquitoes was recorded in villages that were most affected during the RVF epidemic of 2007. Of the tested 150 pools of C. pipiens complex and 45 pools of A. aegypti, none was infected with RVF virus. Conclusions: These results provide insights into unique habitat characterisation relating to mosquito abundances and distribution in RVF epidemic-prone areas of Ngorongoro district in northern Tanzania.

Clement N. Mweya

2015-01-01

252

DEFF Research Database (Denmark)

Diabetes mellitus (DM) is a multi-factorial and complex disease causing autonomic neuropathy and gastrointestinal symptoms in some patients. The neural mechanisms behind these symptoms are poorly understood, but it is believed that both peripheral and central mechanisms are involved. To gain further knowledge of the central mechanisms, the aim of this study was to identify biomarkers for the altered brain activity in type-1 DM patients compared to healthy volunteers (HV), and to correlate the obtained biomarkers to clinical patient scores. The study included 14 DM patients and 15 HV, with brain activity recorded as multi-channel electroencephalography evoked brain potentials (EPs) elicited by painful electrical stimulations in the esophagus. The single-sweep EPs were decomposed by an optimized discrete wavelet transform (DWT), and averaged for each channel. The DWT features from the DM patients were discriminated from the HV by a support vector machine (SVM) applied in regression mode. For the optimal DWT, the discriminative features were extracted and the SVM regression value representing the overall alteration of the EP was correlated to the clinical scores. A classification performance of 86.2% (P=0.01) was obtained by applying a majority voting scheme to the 5 best performing channels. The biomarker was identified as decreased theta band activity. The regression value was correlated to symptoms reported by the patients (P=0.04). The methodology is an improvement of the present approach to study central mechanisms in diabetes mellitus, and may provide a future application for a clinical tool to optimize treatment in individual patients.

Graversen, C; Frokjaer, J B

2012-01-01

253

An important variable in determining the vectorial capacity of mosquito species for arthropod-borne infections is the degree of contact of the vector and the vertebrate reservoir. This parameter can be estimated by examining the host-feeding habits of vectors. Serological and polymerase chain reaction based methods have been used to study the host-feedings patterns of 21 mosquito species from New York, New Jersey, and Tennessee, 19 of which previously have been found infected with West Nile v...

Apperson, Charles S.; Hassan, Hassan K.; Harrison, Bruce A.; Savage, Harry M.; Aspen, Stephen E.; Farajollahi, Ary; Crans, Wayne; Daniels, Thomas J.; Falco, Richard C.; Benedict, Mark; Anderson, Michael; Mcmillen, Larry; Unnasch, Thomas R.

2004-01-01

254

International Nuclear Information System (INIS)

In order to confirm the reliability of a continuous-energy Monte Carlo burn-up calculation code MVP-BURN, it was applied to the burn-up benchmark problems for a high conversion LWR lattice and a BWR lattice with burnable poison rods. The results of MVP-BURN have shown good agreements with those of a deterministic code SRAC95 for burn-up changes of infinite neutron multiplication factor, conversion ratio, power distribution, and number densities of major fuel nuclides. Serious propagation of statistical errors along burn-up was not observed even in a highly heterogeneous lattice. MVP-BURN was applied to the analysis of a post irradiation experiment for a sample fuel irradiated up to 34.1 GWd/t, together with SRAC95 and SWAT. It was confirmed that the effect of statistical errors of MVP-BURN on a burned fuel composition was sufficiently small, and it could give a reference solution for other codes. In the analysis, the results of the three codes with JENDL-3.2 agreed with measured values within an error of 10% for most nuclides. However, large underestimation by about 20% was observed for 238Pu, 242mAm and 244Cm. It is probable that these discrepancies are a common problem for most current nuclear data files. (author)

255

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Full Text Available Abstract Background Anopheles arabiensis is a particularly opportunistic feeder and efficient vector of Plasmodium falciparum in Africa and may invade areas outside its normal range, including areas separated by expanses of barren desert. The purpose of this paper is to demonstrate how spatial models can project future irrigated cropland and potential, new suitable habitat for vectors such as An. arabiensis. Methods Two different but complementary spatial models were linked to demonstrate their synergy for assessing re-invasion potential of An. arabiensis into Upper Egypt as a function of irrigated cropland expansion by 2050. The first model (The Land Change Modeler was used to simulate changes in irrigated cropland using a Markov Chain approach, while the second model (MaxEnt uses species occurrence points, land cover and other environmental layers to project probability of species presence. Two basic change scenarios were analysed, one involving a more conservative business-as-usual (BAU assumption and second with a high probability of desert-to-cropland transition (Green Nile to assess a broad range of potential outcomes by 2050. Results The results reveal a difference of 82,000 sq km in potential An. arabiensis range between the BAU and Green Nile scenarios. The BAU scenario revealed a highly fragmented set of small, potential habitat patches separated by relatively large distances (maximum distance?=?64.02?km, mean?=?12.72?km, SD?=?9.92, while the Green Nile scenario produced a landscape characterized by large patches separated by relatively shorter gaps (maximum distance?=?49.38, km, mean?=?4.51?km, SD?=?7.89 that may be bridged by the vector. Conclusions This study provides a first demonstration of how land change and species distribution models may be linked to project potential changes in vector habitat distribution and invasion potential. While gaps between potential habitat patches remained large in the Green Nile scenario, the models reveal large areas of future habitat connectivity that may facilitate the re-invasion of An. arabiensis from Sudan into Upper Egypt. The methods used are broadly applicable to other land cover changes as they influence vector distribution, particularly those related to tropical deforestation and urbanization processes.

Fuller Douglas O

2012-08-01

256

Energy Technology Data Exchange (ETDEWEB)

Retroviruses are valuable tools in studies of embryonic development, both as gene expression vectors and as cell lineage markers. In this study early chicken blastoderm cells are shown to be permissive for infection by Rous sarcoma virus and derivative replication-defective by Rous sarcoma virus and derivative replication-defective vectors, and, in contrast to previously published data, these cells will readily express viral genes. In cultured blastoderm cells, Rous sarcoma virus stably integrates and is transcribed efficiently, producing infectious virus particles. Using replication-defective vectors encoding the bacterial lacZ gene, the authors further show that blastoderms can be infected in culture and in ovo. In ovo, lacZ expression is seen within 24 hours of virus inoculation, and by 96 hours stably expressing clones of cells are observed in diverse tissues throughout the embryo, including epidermis, somites, and heart, as well as in extraembryonic membranes. Given the rapid onset of vector expression and the broad range of permissive cell types, it should be feasible to use Rous sarcoma virus-derived retroviruses as early lineage markers and expression vectors beginning at the blastoderm stage of avian embryogenesis.

Reddy, S.T.; Stoker, A.W.; Bissell, M.J. (Lawrence Berkeley Lab., CA (United States))

1991-12-01

257

In this manuscript, we synthesized the potential non viral vector for gene delivery with proper transfection efficiency and low cytotoxicity. Polyethylenimine (PEI) is a well-known cationic polymer which has high positive surface charge for condensing plasmid DNA. However; it is highly cytotoxic in many cell lines because of the high surface charge, non-biodegradability and non-biocompatibility. To enhance PEI biodegradability, the graft copolymer “PEG-g-PEI” was synthesized. To t...

Ghiamkazemi, S.; Amanzadeh, A.; Dinarvand, R.; Rafiee-tehrani, M.; Amini, M.

2010-01-01

258

Energy Technology Data Exchange (ETDEWEB)

We present an exact solution of the (1+1)-dimensional Dirac equation with vector and scalar linear potentials in the context of modified quantum mechanics characterized by the presence of a non-zero minimum uncertainty in position. The bound-states energy spectrum and the corresponding momentum space wavefunctions are exactly obtained. Our findings are compared with approximated results existing in the literature.

Chargui, Y., E-mail: yassine.chargui@gmail.co [Unite de Recherche de Physique Nucleaire et des Hautes Energies, Faculte des Sciences de Tunis, 1080 Tunis (Tunisia); Trabelsi, A. [Unite de Recherche de Physique Nucleaire et des Hautes Energies, Faculte des Sciences de Tunis, 1080 Tunis (Tunisia); Centre National des Sciences et Technologies Nucleaires, Technopole de Sidi-Thabet 2020 (Tunisia); Chetouani, L. [Departement de Physique Theorique, Institut de Physique, Universite de Constantine, Route Ain El Bey, Constantine (Algeria)

2010-01-11

259

Several mathematical formulae are used nowadays in order to compute a magnetic torque. We demonstrate that its more general expression is the vectorial product of the current density with the vector potential. We associate this Larmor's torque with Amp\\`{e}re's force and more specifically with Helmholtz mechanical tension, which is at the origin of the longitudinal stresses in "open" circuits carrying current. We show that Amp\\`{e}re's force enters into the realm of Newtonia...

Rousseaux, Germain

2005-01-01

260

SWAT3.1 - the integrated burnup code system driving continuous energy Monte Carlo codes MVP and MCNP

International Nuclear Information System (INIS)

Integrated burnup calculation code system SWAT is a system that combines neutronics calculation code SRAC,which is widely used in Japan, and point burnup calculation code ORIGEN2. It has been used to evaluate the composition of the uranium, plutonium, minor actinides and the fission products in the spent nuclear fuel. Based on this idea, the integrated burnup calculation code system SWAT3.1 was developed by combining the continuous energy Monte Carlo code MVP and MCNP, and ORIGEN2. This enables us to treat the arbitrary fuel geometry and to generate the effective cross section data to be used in the burnup calculation with few approximations. This report describes the outline, input data instruction and several examples of the calculation. (author)

261

Scientific Electronic Library Online (English)

Full Text Available OBJETIVOS: Evaluar el costo-beneficio de una intervención de control de mosquitos adultos con fumigación, junto con actividades de control de formas inmaduras de Aedes aegypti, para evitar la transmisión en una situación de alto riesgo. MÉTODOS: Se realizó un análisis de costo-beneficio desde una pe [...] rspectiva social. Se comparó una intervención para el control de mosquitos adultos y formas inmaduras contra una hipótesis de no-intervención, de enero a abril de 2007, en la ciudad de Clorinda, Argentina. Se consideraron los costos directos y los beneficios indirectos e intangibles, estandarizados a dólares internacionales (I$) utilizando la paridad de poder adquisitivo. Se asumió una incidencia de 50 casos de dengue por 1 000 habitantes en la hipótesis de no-intervención. RESULTADOS: De enero a abril de 2007 se presentaron 176 casos de dengue en Clorinda, pero sólo cinco fueron autóctonos. El valor presente neto fue de I$ 196 879 en la estrategia de aplicación de control, mientras que en la de no aplicación se calculó en I$ -106 724, lo que significaría un ahorro de I$ 303 602 (I$ 6,46 por habitante) con la intervención. El análisis de sensibilidad evidenció que, con más de 1 363 casos de dengue (incidencia total de 29 por 1 000 habitantes) y un caso de dengue hemorrágico, la intervención es costo-benéfica. CONCLUSIONES: Los resultados sugieren que el control vectorial, incluyendo la fumigación para mosquitos adultos, debe evaluarse en situaciones de alto riesgo de transmisión como una alternativa costo-benéfica en países no endémicos. Abstract in english OBJECTIVES: To evaluate the cost-benefit of an intervention utilizing fumigation against adult mosquitoes along with actions to control immature Aedes aegypti to prevent transmission in a high-risk area. METHODS: A cost-benefit analysis was performed from the social perspective. A program to control [...] both adult mosquitoes and immature forms was compared to a non-intervention hypothesis, from January to April 2007, in the city of Clorinda, Argentina. Direct costs, as well as indirect and intangible benefits, were taken into account and standardized in international dollars (I$) using purchasing power parity. An incidence rate of 50 cases of dengue per 1 000 inhabitants was used in the non-intervention hypothesis. RESULTS: From January to April 2007 there were 176 cases of dengue in Clorinda, but only five were autochthonous. The net present value was I$ 196 879 with the control strategy, whereas the non-intervention was calculated to be I$ -106 724, indicating a savings of I$ 303 602 (I$ 6.46 per inhabitant) for the intervention. The sensitivity analysis showed that, with more than 1 363 cases of dengue (total incidence rate of 29 per 1 000 inhabitants) and one case of dengue hemorrhagic fever, there is a cost-benefit to intervention. CONCLUSIONS: The results suggest that vector control, including fumigation of adult mosquitoes, should be considered in high-risk areas as a cost-effective option for non-endemic countries.

Pablo Wenceslao, Orellano; Elena, Pedroni.

2008-08-01

262

Directory of Open Access Journals (Sweden)

Full Text Available OBJETIVOS: Evaluar el costo-beneficio de una intervención de control de mosquitos adultos con fumigación, junto con actividades de control de formas inmaduras de Aedes aegypti, para evitar la transmisión en una situación de alto riesgo. MÉTODOS: Se realizó un análisis de costo-beneficio desde una perspectiva social. Se comparó una intervención para el control de mosquitos adultos y formas inmaduras contra una hipótesis de no-intervención, de enero a abril de 2007, en la ciudad de Clorinda, Argentina. Se consideraron los costos directos y los beneficios indirectos e intangibles, estandarizados a dólares internacionales (I$ utilizando la paridad de poder adquisitivo. Se asumió una incidencia de 50 casos de dengue por 1 000 habitantes en la hipótesis de no-intervención. RESULTADOS: De enero a abril de 2007 se presentaron 176 casos de dengue en Clorinda, pero sólo cinco fueron autóctonos. El valor presente neto fue de I$ 196 879 en la estrategia de aplicación de control, mientras que en la de no aplicación se calculó en I$ -106 724, lo que significaría un ahorro de I$ 303 602 (I$ 6,46 por habitante con la intervención. El análisis de sensibilidad evidenció que, con más de 1 363 casos de dengue (incidencia total de 29 por 1 000 habitantes y un caso de dengue hemorrágico, la intervención es costo-benéfica. CONCLUSIONES: Los resultados sugieren que el control vectorial, incluyendo la fumigación para mosquitos adultos, debe evaluarse en situaciones de alto riesgo de transmisión como una alternativa costo-benéfica en países no endémicos.OBJECTIVES: To evaluate the cost-benefit of an intervention utilizing fumigation against adult mosquitoes along with actions to control immature Aedes aegypti to prevent transmission in a high-risk area. METHODS: A cost-benefit analysis was performed from the social perspective. A program to control both adult mosquitoes and immature forms was compared to a non-intervention hypothesis, from January to April 2007, in the city of Clorinda, Argentina. Direct costs, as well as indirect and intangible benefits, were taken into account and standardized in international dollars (I$ using purchasing power parity. An incidence rate of 50 cases of dengue per 1 000 inhabitants was used in the non-intervention hypothesis. RESULTS: From January to April 2007 there were 176 cases of dengue in Clorinda, but only five were autochthonous. The net present value was I$ 196 879 with the control strategy, whereas the non-intervention was calculated to be I$ -106 724, indicating a savings of I$ 303 602 (I$ 6.46 per inhabitant for the intervention. The sensitivity analysis showed that, with more than 1 363 cases of dengue (total incidence rate of 29 per 1 000 inhabitants and one case of dengue hemorrhagic fever, there is a cost-benefit to intervention. CONCLUSIONS: The results suggest that vector control, including fumigation of adult mosquitoes, should be considered in high-risk areas as a cost-effective option for non-endemic countries.

Pablo Wenceslao Orellano

2008-08-01

263

International Nuclear Information System (INIS)

Mean field models of the nucleon and the delta are established with the two-quark vector Richardson potential along with various prescriptions for a running quark mass (single particle) in the Dirac-Hartree-Fock formalism. The N-? splitting is obtained from colour magnetic interaction and the results for gA and magnetic moment are discussed. An effective density dependent one body potential U(?) for quarks at a given density ? inside the nucleon, is derived. Asymptotic freedom and confinement properties are built-in in U (?) and the model dependence is restricted to the intermediate densities. (author). 18 refs, 1 fig., 2 tabs

264

Directory of Open Access Journals (Sweden)

Full Text Available Abstract The field of drug delivery focuses primarily on delivering small organic molecules or DNA/RNA as therapeutics and has largely ignored the potential for delivering catalytically active transition metal ions and complexes. The delivery of a variety of transition metals has potential for inducing apoptosis in targeted cells. The chief aims of this work were the development of a suitable delivery vector for a prototypical transition metal, Cu2+, and demonstration of the ability to impact cancer cell viability via exposure to such a Cu-loaded vector. Carboxylate-functionalized nanoparticles were synthesized by free radical polymerization and were subsequently loaded with Cu2+ via binding to particle-bound carboxylate functional groups. Cu loading and release were characterized via ICP MS, EDX, XPS, and elemental analysis. Results demonstrated that Cu could be loaded in high weight percent (up to 16 wt.% and that Cu was released from the particles in a pH-dependent manner. Metal release was a function of both pH and the presence of competing ligands. The toxicity of the particles was measured in HeLa cells where reductions in cell viability greater than 95% were observed at high Cu loading. The combined pH sensitivity and significant toxicity make this copper delivery vector an excellent candidate for the targeted killing of disease cells when combined with an effective cellular targeting strategy.

Harris Alesha

2011-01-01

265

International Nuclear Information System (INIS)

The analytical expressions for the eigenvalues and eigenvectors of the Klein–Gordon equation for q-deformed Woods–Saxon plus new generalized ring shape potential are derived within the asymptotic iteration method in two cases, namely, the case of equal mixed vector and scalar potentials and the case when the vector potential is chosen to be equal to the q-deformed Woods–Saxon plus the new generalized ring-shaped potential while the scalar one is taken equal to the ring-shaped potential. The latter is considered as a small perturbation. The obtained eigenvalues are given in a closed form and the corresponding normalized eigenvectors, for any l, are formulated in terms of the generalized Jacobi polynomials for the radial part of the Klein–Gordon equation and associated Legendre polynomials for its angular one. When the shape deformation is canceled, we recover the same solutions previously obtained by the Nikiforov–Uvarov method for the standard spherical Woods–Saxon potential. It is also shown that, from the obtained results, we can derive the solutions of this problem for Hulthen potential. (author)

266

Energy Technology Data Exchange (ETDEWEB)

In this paper techniques are presented for preconditioning equations generated by discretizing constrained vector integral equations associated with magnetoquasistatic analysis. Standard preconditioning approaches often fail on these problems. The authors present a specialized preconditioning technique and prove convergence bounds independent of the constraint equations and electromagnetic excitation frequency. Computational results from analyzing several electronic packaging examples are given to demonstrate that the new preconditioning approach can sometimes reduce the number of GMRES iterations by more than an order of magnitude.

Kamon, M.; Phillips, J.R. [Massachusetts Institute of Technology, Cambridge, MA (United States)

1994-12-31

267

There is a risk that irrigation schemes that have been developed to enhance sugarcane, Saccharum spp, cropping on the island of Réunion could markedly broaden the distribution range in which outbreaks of the insect Persinkiella saccharicida Kirkaldy (Homoptera: Delphacidae), a sugarcane Fiji virus disease vector, have already occurred. This trend was confirmed by the results of laboratory studies and monthly surveys carried out in six sugarcane fields distributed throughout the island. A com...

Vercambre, Bernard

2010-01-01

268

Directory of Open Access Journals (Sweden)

Full Text Available INTRODUÇÃO: Em alguns bairros costeiros de São Luís, Maranhão, a prevalência da dirofilariose chega a mais de 40% entre os cães domiciliados. Porém, desconhecem-se os vetores naturais, tanto lá quanto no resto do Nordeste do país. O objetivo do estudo foi identificar os prováveis vetores dessa parasitose. MÉTODOS: Realizaram-se coletas mensais de mosquitos em um bairro costeiro de São Luís, MA, de março de 1996 a maio de 1997, no peridomicílio, tendo cão e homem como iscas. Os mosquitos foram dissecados para a pesquisa de larvas da Dirofilaria immitis. RESULTADOS: Coletaram-se 1.738 mosquitos de 11 espécies. Culex quinquefasciatus, capturada todos os meses, porém menos freqüente na estação chuvosa, correspondeu a 54,5% do total, seguido de Aedes albopictus (20,3%, Aedes taeniorhynchus e Aedes scapularis (ambos 11%. Larvas de D.immitis foram encontradas em 0,1% dos Cx. quinquefasciatus e 0,5% dos Ae. taeniorhynchus. CONCLUSÕES: Ae. taeniorhynchus e Cx. quinquefasciatus foram considerados vetores potenciais da dirofilariose em São Luís. A importância local de Cx. quinquefasciatus como transmissor primário da D. immitis necessita ser melhor avaliada.INTRODUCTION: In some coastal districts of São Luís, capital of the state of Maranhão, Brazil, the prevalence of Dirofilaria immitis is more than 40% in house dogs. Natural potential vectors, as found in other areas of Northeastern Brazil, are unknown. The aim of this study was to identify probable vectors of the disease. METHODS: Mosquito catches were performed at a coastal, district Olho d'Água, in S. Luís, to look for local potential vectors. Captures were carried out monthly, from March 1996 to May 1997, outdoors, having a man and a dog as baits. Mosquitoes were dissected for D. immitis larvae. RESULTS: A total of 1,738 mosquitoes belonging to 11 species were collected. Culex quinquefasciatus, the only species collected every month, was more frequently in the dry season. It accounted for 54.5% of the total, followed by Aedes albopictus (20.3%, Ae. scapularis (11% and Ae. taeniorhynchus (11%. D. immitis larvae were detected in 0.1% of the Cx. quinquefasciatus dissected (L3 in the Malpighian tubules and 0.5% of the Ae. taeniorhynchus (L2 in the Malpighian tubules. CONCLUSION: Ae. taeniorhynchus and Cx. quinquefasciatus are considered natural potential vectors of the canine heartworm in São Luís. The role of Cx. quinquefasciatus as primary vector of D. immitis, however, needs further evaluation.

Silvia MM Ahid

1999-12-01

269

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese INTRODUÇÃO: Em alguns bairros costeiros de São Luís, Maranhão, a prevalência da dirofilariose chega a mais de 40% entre os cães domiciliados. Porém, desconhecem-se os vetores naturais, tanto lá quanto no resto do Nordeste do país. O objetivo do estudo foi identificar os prováveis vetores dessa paras [...] itose. MÉTODOS: Realizaram-se coletas mensais de mosquitos em um bairro costeiro de São Luís, MA, de março de 1996 a maio de 1997, no peridomicílio, tendo cão e homem como iscas. Os mosquitos foram dissecados para a pesquisa de larvas da Dirofilaria immitis. RESULTADOS: Coletaram-se 1.738 mosquitos de 11 espécies. Culex quinquefasciatus, capturada todos os meses, porém menos freqüente na estação chuvosa, correspondeu a 54,5% do total, seguido de Aedes albopictus (20,3%), Aedes taeniorhynchus e Aedes scapularis (ambos 11%). Larvas de D.immitis foram encontradas em 0,1% dos Cx. quinquefasciatus e 0,5% dos Ae. taeniorhynchus. CONCLUSÕES: Ae. taeniorhynchus e Cx. quinquefasciatus foram considerados vetores potenciais da dirofilariose em São Luís. A importância local de Cx. quinquefasciatus como transmissor primário da D. immitis necessita ser melhor avaliada. Abstract in english INTRODUCTION: In some coastal districts of São Luís, capital of the state of Maranhão, Brazil, the prevalence of Dirofilaria immitis is more than 40% in house dogs. Natural potential vectors, as found in other areas of Northeastern Brazil, are unknown. The aim of this study was to identify probable [...] vectors of the disease. METHODS: Mosquito catches were performed at a coastal, district Olho d'Água, in S. Luís, to look for local potential vectors. Captures were carried out monthly, from March 1996 to May 1997, outdoors, having a man and a dog as baits. Mosquitoes were dissected for D. immitis larvae. RESULTS: A total of 1,738 mosquitoes belonging to 11 species were collected. Culex quinquefasciatus, the only species collected every month, was more frequently in the dry season. It accounted for 54.5% of the total, followed by Aedes albopictus (20.3%), Ae. scapularis (11%) and Ae. taeniorhynchus (11%). D. immitis larvae were detected in 0.1% of the Cx. quinquefasciatus dissected (L3 in the Malpighian tubules) and 0.5% of the Ae. taeniorhynchus (L2 in the Malpighian tubules). CONCLUSION: Ae. taeniorhynchus and Cx. quinquefasciatus are considered natural potential vectors of the canine heartworm in São Luís. The role of Cx. quinquefasciatus as primary vector of D. immitis, however, needs further evaluation.

Silvia MM, Ahid; Ricardo, Lourenço-de-Oliveira.

1999-12-01

270

Scientific Electronic Library Online (English)

Full Text Available SciELO Public Health | Language: Portuguese Abstract in portuguese INTRODUÇÃO: Em alguns bairros costeiros de São Luís, Maranhão, a prevalência da dirofilariose chega a mais de 40% entre os cães domiciliados. Porém, desconhecem-se os vetores naturais, tanto lá quanto no resto do Nordeste do país. O objetivo do estudo foi identificar os prováveis vetores dessa paras [...] itose. MÉTODOS: Realizaram-se coletas mensais de mosquitos em um bairro costeiro de São Luís, MA, de março de 1996 a maio de 1997, no peridomicílio, tendo cão e homem como iscas. Os mosquitos foram dissecados para a pesquisa de larvas da Dirofilaria immitis. RESULTADOS: Coletaram-se 1.738 mosquitos de 11 espécies. Culex quinquefasciatus, capturada todos os meses, porém menos freqüente na estação chuvosa, correspondeu a 54,5% do total, seguido de Aedes albopictus (20,3%), Aedes taeniorhynchus e Aedes scapularis (ambos 11%). Larvas de D.immitis foram encontradas em 0,1% dos Cx. quinquefasciatus e 0,5% dos Ae. taeniorhynchus. CONCLUSÕES: Ae. taeniorhynchus e Cx. quinquefasciatus foram considerados vetores potenciais da dirofilariose em São Luís. A importância local de Cx. quinquefasciatus como transmissor primário da D. immitis necessita ser melhor avaliada. Abstract in english INTRODUCTION: In some coastal districts of São Luís, capital of the state of Maranhão, Brazil, the prevalence of Dirofilaria immitis is more than 40% in house dogs. Natural potential vectors, as found in other areas of Northeastern Brazil, are unknown. The aim of this study was to identify probable [...] vectors of the disease. METHODS: Mosquito catches were performed at a coastal, district Olho d'Água, in S. Luís, to look for local potential vectors. Captures were carried out monthly, from March 1996 to May 1997, outdoors, having a man and a dog as baits. Mosquitoes were dissected for D. immitis larvae. RESULTS: A total of 1,738 mosquitoes belonging to 11 species were collected. Culex quinquefasciatus, the only species collected every month, was more frequently in the dry season. It accounted for 54.5% of the total, followed by Aedes albopictus (20.3%), Ae. scapularis (11%) and Ae. taeniorhynchus (11%). D. immitis larvae were detected in 0.1% of the Cx. quinquefasciatus dissected (L3 in the Malpighian tubules) and 0.5% of the Ae. taeniorhynchus (L2 in the Malpighian tubules). CONCLUSION: Ae. taeniorhynchus and Cx. quinquefasciatus are considered natural potential vectors of the canine heartworm in São Luís. The role of Cx. quinquefasciatus as primary vector of D. immitis, however, needs further evaluation.

Silvia MM, Ahid; Ricardo, Lourenço-de-Oliveira.

1999-12-01

271

International Nuclear Information System (INIS)

Weighting of given doses from parallel opposed fields is a widespread practice in radiation therapy of cancer in the tonsillar region. In order to determine when weighting is useful, dose distributions on the central axis were calculated for various energies (60Co, 4-, 8-, 15-, and 24-MVp photons), weighting factors, and field separations. Criteria for judging the usefulness of weighting were (i) that variation in the dose across the tumor volume not exceed 10%, and (ii) that the dose to critical tissues outside the target volume be at least 20% less than target volume dose. The clinical situation that met these criteria was a lateral lesion that extended to less than one-third of the transverse diameter of the head, treated with either 60Co, 8, or 4 MVp with 4:1 weighting. Under these conditions, weighting was considered to be justified

272

Aedes borne viruses represent public health problems in southern countries and threat to emerge in the developed world. Their control is currently based on vector population control. Much effort is being devoted to develop new tools to control such arbovirus. Recent findings suggest that the evaluation of human antibody (Ab) response to arthropod salivary proteins is relevant to measuring the level of human exposure to mosquito bites. Using an immunoepidemiological approach, the present study aimed to assess the usefulness of the salivary biomarker for measuring the efficacy of Ae. albopictus control strategies in La Reunion urban area. The antisaliva Ab response of adult humans exposed to Ae. albopictus was evaluated before and after vector control measures. Our results showed a significant correlation between antisaliva Ab response and the level of exposure to vectors bites. The decrease of Ae. albopictus density has been detected by this biomarker two weeks after the implementation of control measures, suggesting its potential usefulness for evaluating control strategies in a short time period. The identification of species specific salivary proteins/peptides should improve the use of this biomarker. PMID:24822216

Doucoure, Souleymane; Mouchet, François; Cornelie, Sylvie; Drame, Papa Makhtar; D'Ortenzio, Eric; DeHecq, Jean Sébastien; Remoue, Franck

2014-01-01

273

The subject of this thesis is the evaluation of the discovery potential of the ATLAS detector at the Large Hadron Collider for the Standard Model Higgs boson in vector boson fusion (VBF) production and a subsequent decay into a $ au$-lepton pair (H to tau tau). This is one of the most promising discovery channels in the low mass range, which is the mass range favored from precision measurements of the electroweak interaction. The decay modes where both $ au$ leptons decay leptonically and where one $ au$ lepton decays leptonically and the other one hadronically were studied. The characteristic vector boson fusion topology, which consists of two jets in the forward regions of the detector and the Higgs boson decay products in the central region, provides a unique signature allowing the suppression of background. In addition, since vector boson fusion is a purely electroweak process, no QCD activity is expected and thus no central jets are expected for signal events. This allows the central jet veto cut applica...

Varouchas, D

2009-01-01

274

International Nuclear Information System (INIS)

This paper studies the sorption of chlorine complexes of ruthenium (IV) on the graft copolymer of a polyacrylonitrile fiber with poly-2-methyl-5-vinylpyridine (PAN-MVP). The composition of the fiber is illustrated. It is shown that sorption of chlorine complexes of ruthenium (IV) from acid solutions by a pyridine fiber sorbent takes place according to an anion-exchange mechanism and is due to the formation of compounds of the diamine type (Ru(RPy)2Cl4)

275

Energy Technology Data Exchange (ETDEWEB)

ABCXYZ is a computer code for obtaining the Cartesian components of the vector potential and the magnetic field on an observed grid from an arrangement of current-carrying wires. Arbitrary combinations of straight line segments, arcs, and loops are allowed in the specification of the currents. Arbitrary positions and orientations of the current-carrying elements are also allowed. Specification of the wire diameter permits the computation of well-defined fields, even in the interiors of the conductors. An optical feature generates magnetic field lines. Extensive graphical and printed output is available to the user including contour, grid-line, and field-line plots. 12 figures, 1 table.

Anderson, D.V.; Breazeal, J.; Finan, C.H.; Johnston, B.M.

1976-09-14

276

International Nuclear Information System (INIS)

The hydrogen molecular ion H2+ is among the best theoretically studied quantum-mechanical systems. At the same time, its magnetic properties associated with the orbital motion of the electron in the field of two protons still remain insufficiently studied. In this work, therefore, the components of the electronic orbital magnetic susceptibility and the electronic contribution of the rotational g factor of the hydrogen molecular ion are calculated by the vector-potential variation method over the internuclear separation range 1-3 a.u. 11 refs., 1 tab

277

We decouple the Dirac's radial equations in $D+1$ dimensions with Coulomb-type scalar and vector potentials through appropriate transformations. We study each of these uncoupled second-order equations in an algebraic way by using an $su(1,1)$ algebra realization. Based on the theory of irreducible representations, we find the energy spectrum and the radial eigenfunctions. We construct the Perelomov coherent states for the Sturmian basis, which is the basis for the unitary irreducible representation of the $su(1,1)$ Lie algebra. The physical radial coherent states for our problem are obtained by applying the inverse original transformations to the Sturmian coherent states.

Ojeda-Guillen, D; Granados, V D

2013-01-01

278

The einkorn wheat mutant mvp-1 (maintained vegetative phase 1) has a non-flowering phenotype caused by deletions including, but not limited to, the genes CYS, PHYC, and VRN1. However, the impact of these deletions on global gene expression is still unknown. Transcriptome analysis showed that these deletions caused the upregulation of several pathogenesis-related (PR) and jasmonate-responsive genes. These results suggest that jasmonates may be involved in flowering and vernalization in wheat. To test this hypothesis, jasmonic acid (JA) and methyl jasmonate (MeJA) content in mvp and wild-type plants was measured. The content of JA was comparable in all plants, whereas the content of MeJA was higher by more than 6-fold in mvp plants. The accumulation of MeJA was also observed in vernalization-sensitive hexaploid winter wheat during cold exposure. This accumulation declined rapidly once plants were deacclimated under floral-inductive growth conditions. This suggests that MeJA may have a role in floral transition. To confirm this result, we treated vernalization-insensitive spring wheat with MeJA. The treatment delayed flowering with significant downregulation of both TaVRN1 and TaFT1 genes. These data suggest a role for MeJA in modulating vernalization and flowering time in wheat. PMID:24683181

Diallo, Amadou Oury; Agharbaoui, Zahra; Badawi, Mohamed A; Ali-Benali, Mohamed Ali; Moheb, Amira; Houde, Mario; Sarhan, Fathey

2014-06-01

279

International Nuclear Information System (INIS)

To evaluate the effect of MVP chemotherapy and hyperfractionated radiotherapy in Stage III unresectable non small cell lung cancer (NSCLC), authors have conducted a prospective randomized study since January 1991. Stage IIIa or IIIb unresectable NSCLC patients were treated with hyperfractionated radiotherapy (120 cGy/fx BID) up to 6500 cGY following 3 cycles of induction MVP (Mitomycin C 6 mg/m2, vinblastine 6 mg/m2, Cisplatin 60 mg/m2) and randomized for either observation or 3 cycles of maintenance MVP chemotherapy. Until August 1991, 18 patients were registered to this study. 4 cases were stage IIIa and 14 were stage IIIb. Among 18 cases 2 were lost after 2 cycles of chemotherapy, and 16 were analyzed for this preliminary report. The response rate of induction chemotherapy was 62.5%; partial response, 50% and minimal response, 12.5%. Residual tumor of the one partial responder was completely disappeared after radiotherapy. Among 6 cases who were progressed during induction chemotherapy, 4 of them were also progressed after radiotherapy. All patients were tolerated BID radiotherapy without definite increase of acute complications, compared with conventional radiotherapy group. But at the time of this report, one patient expired in two month after the completion of the radiotherapy because of treatment related complication. Although the longer follow up is needed, authors are encouraged with higher response rate and acceptable toxicitigher response rate and acceptable toxicity of this treatment. Authors believe that this study is worthwhile to continue

280

International Nuclear Information System (INIS)

Validation of the continuous-energy Monte Carlo criticality-safety analysis system, comprising the MVP code and neutron cross sections based on JENDL-3.2, was examined using benchmarks evaluated in the 'International Handbook of Evaluated Criticality Safety Benchmark Experiments'. Eight experiments (116 configurations) for the plutonium solution and plutonium-uranium mixture systems performed at Valduc, Battelle Pacific Northwest Laboratories, and other facilities were selected and used in the studies. The averaged multiplication factors calculated with MVP and MCNP-4B using the same neutron cross-section libraries based on JENDL-3.2 were in good agreement. Based on methods provided in the Japanese nuclear criticality-safety handbook, the estimated criticality lower-limit multiplication factors to be used as a subcriticality criterion for the criticality-safety evaluation of nuclear facilities were obtained. The analysis proved the applicability of the MVP code to the criticality-safety analysis of nuclear fuel facilities, particularly to the analysis of systems fueled with plutonium and in homogeneous and thermal-energy conditions

281

International Nuclear Information System (INIS)

The linear heat rates of the power-to-melt (PTM) tests, performed with B5D-1 and B5D-2 subassemblies on the Experimental Fast Reactor 'JOYO', are evaluated with the continuous energy Monte-Carlo code, MVP. We can apply a whole core model to MVP, but it takes very long time for the calculation. Therefore, judging from the structure of B5D subassembly, we used the MVP code to calculate the radial distribution of linear heat rate and used the deterministic method to calculate the axial distribution. We also derived the formulas for this method. Furthermore, we evaluated the error of the linear heat rate, by evaluating the experimental error of the reactor power, the statistical error of Monte-Carlo method, the calculational model error of the deterministic method and so on. On the other hand, we also evaluated the burnup rate of the B5D assembly and compared with the measured value in the post-irradiation test. The main results are following: B5D-1 (B5101, F613632, core center). Linear heat rate: 600 W/cm±2.2%. Burnup rate: 0.977. B5D-2 (B5214, G80124, core center). Linear heat rate: 641 W/cm±2.2%. Burnup rate: 0.886. (author)

282

International Nuclear Information System (INIS)

A conceptual design study has been carried out with a Monte Carlo transport code on an active nondestructive assay system for low-level uranium-bearing wastes discharged from an uranium enrichment plant. Delayed neutrons from photofission of uranium isotopes in the steel waste are counted with this system to confirm that the activity concentration of this waste is below the clearance level. The present design work needs a coupled neutron/photon transport code which can numerically simulate the photonuclear reaction and the resultant emission of neutrons. We have modified a continuous-energy Monte Carlo transport code MVP to equip it with a function to simulate the emission of photoneutrons along with the delayed neutrons from photofission. The photonuclear data library for the modified MVP code was prepared on the basis of evaluated photonuclear data by IAEA. For the 235U and 238U, we employed evaluated data in the JENDL photonuclear data 2004, which stores complete delayed neutron emission data for these isotopes. With this code system, a time-dependent simulation of neutron counts was made for the assay system, which consisted of a 15 MeV end-point bremsstrahlung photon source, helium-3 neutron detectors and the waste. The present paper describes the modification to the MVP code and the results of design study. (author)

283

Vector inflation by kinetic coupled gravity

Vector inflation is a newly established model where inflation is driven by non-minimally coupled massive vector fields with a potential term. This model is similar to the model of chaotic inflation with scalar fields, except that for vector fields the isotropy of expansion is achieved either by considering a triplet of orthogonal vector fields or $N$ randomly oriented independent vector fields. We introduce a new version of vector inflation where the vector field has no pote...

Darabi, F.; Parsiya, A.

2014-01-01

284

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Rift Valley fever (RVF is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera. Methods Experiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Khartoum and White Nile states, identified and species abundance was calculated. All samples were frozen individually for further virus detection. Total RNA was extracted from individual insects and RVF virus was detected from Culex, Anopheles and Aedes species using RT-PCR. In addition, data were collected about human cases up to November 24th, 2007 to asses the situation of the disease in affected states. Furthermore, a historical background of the RVF outbreaks was discussed in relation to global climatic anomalies and incriminated vector species. Results A total of 978 mosquitoes, belonging to 3 genera and 7 species, were collected during Sudan outbreak, 2007. Anopheles gambiae arabiensis was the most frequent species (80.7% in White Nile state. Meanwhile, Cx. pipiens complex was the most abundant species (91.2% in Khartoum state. RT-PCR was used and successfully amplified 551 bp within the M segment of the tripartite negative-sense single stranded RNA genome of RVFV. The virus was detected in female, male and larval stages of Culex and Anopheles species. The most affected human age interval was 15-29 years old followed by ? 45 years old, 30-44 years old, and then 5-14 years old. Regarding to the profession, housewives followed by farmers, students, shepherd, workers and the free were more vulnerable to the infection. Furthermore, connection between human and entomological studies results in important human case-vulnerability relatedness findings. Conclusion Model performance, integrated with epidemiologic and environmental surveillance systems should be assessed systematically for RVF and other mosquito-borne diseases using historical epidemiologic and satellite monitoring data. Case management related interventions; health education and vector control efforts are extremely effective in preparedness for viral hemorrhagic fever and other seasonal outbreaks.

Galal Fatma H

2010-03-01

285

Symbolic computer vector analysis

A MACSYMA program is described which performs symbolic vector algebra and vector calculus. The program can combine and simplify symbolic expressions including dot products and cross products, together with the gradient, divergence, curl, and Laplacian operators. The distribution of these operators over sums or products is under user control, as are various other expansions, including expansion into components in any specific orthogonal coordinate system. There is also a capability for deriving the scalar or vector potential of a vector field. Examples include derivation of the partial differential equations describing fluid flow and magnetohydrodynamics, for 12 different classic orthogonal curvilinear coordinate systems.

Stoutemyer, D. R.

1977-01-01

286

Malaria control in developing countries is based largely on vector eradication by the use of mosquito larvicides which is an ideal method for controlling mosquito and the related epidemics. On account of ecohazardous nature, nontarget specificity of chemical insecticides and evidences of developing resistance against them in the exposed species, currently, importance of secondary plant metabolites has been acknowledged. Insecticides of plant origin are environmentally safe, degradable, and target specific. In view of this fact, the present work highlights the larvicidal property of extracts of Amaranthus oleracea and Euphorbia hirta against the third instar larvae of Anopheles stephensi, the urban malaria vector. LC(50) values for the carbon tetrachloride fraction of A. oleracea against larvae are 17,768.00 and 13,780.00 ppm after 24 and 48 h of exposure accordingly. For the methanol extract of the same, LC(50) values are 15,541.00 and 10,174.00 ppm after 24 and 48 h of exposure. In the case of petroleum ether extract, LC(50) values after 24 and 48 h of exposure are 848.75 and 311.50 ppm. LC(50) values for carbon tetrachloride extracts of E. hirta against the larvae are 11,063.00 and 10,922.00 ppm after 24 and 48 h of exposure, respectively. For methanol extract of the same extract, the LC(50) values are 19,280.00 and 18,476.00 ppm after 24 and 48 h of exposure. In the case of petroleum ether extract, LC(50) values after a 24- and 48-h exposure period are 9,693.90 and 7,752.80 ppm. The results obtained for petroleum extracts of A. oleracea are encouraging and there are probabilities that the active principle contained in this extract may be more effective than its crude form and may serve as ecofriendly mosquito larvicide. PMID:19838734

Sharma, Preeti; Mohan, Lalit; Srivastava, C N

2009-12-01

287

To better understand the role of vector transmission of aquatic viruses, we established an in vivo virus-parasite challenge specifically to address (1) whether Lepeophtheirus salmonis can acquire infectious haematopoietic necrosis virus (IHNV) after water bath exposure or via parasitizing infected Atlantic salmon Salmo salar and if so, define the duration of this association and (2) whether L. salmonis can transmit IHNV to naive Atlantic salmon and whether this transmission requires attachment to the host. Salmon lice which were water bath-exposed to 1 x 10(5) plaque-forming units (pfu) ml(-1) of IHNV for 1 h acquired the virus (2.1 x 10(4) pfu g(-1)) and remained IHNV-positive for 24 h post exposure. After parasitizing IHNV-infected hosts (viral titer in fish mucus 3.3 x 10(4) pfu ml(-1)) salmon lice acquired IHNV (3.4 x 10(3) pfu g(-1)) and remained virus-positive for 12 h. IHNV-positive salmon lice generated through water bath exposure or after parasitizing infected Atlantic salmon successfully transmitted IHNV, resulting in 76.5 and 86.6% of the exposed Atlantic salmon testing positive for IHNV, respectively. In a second experiment, only salmon lice that became IHNV-positive through water bath exposure transmitted IHNV to 20% of the naive fish, and no virus was transmitted when IHNV-infected salmon lice were cohabitated but restrained from attaching to naive fish. Under laboratory conditions, adult L. salmonis can acquire IHNV and transmit it to naive Atlantic salmon through parasitism. However, the ephemeral association of IHNV with L. salmonis indicates that the salmon louse act as a mechanical rather than a biological vector or reservoir. PMID:22303632

Jakob, E; Barker, D E; Garver, K A

2011-12-01

288

International Nuclear Information System (INIS)

Critical experiments in the FCA and ZPPR-9 assemblies were re-analyzed systematically by using a continuous-energy Monte Carlo code MVP with the JENDL-3.2 library. The experimental geometries were simulated almost as built and the neutronic parameters were calculated with the physics model where all neutron reactions given in the evaluated nuclear data library were treated explicitly. As a result, the calculated keff values underestimated the experimental ones by 0.5-0.8%?k/k except for FCA X-2. The calculated results for most reaction rate distributions and central reaction rate ratios agree well with the measured ones within the uncertainties. Furthermore, in order to investigate the cause of the underestimation of the keff values, re-calculations were performed using the modified JENDL-3.2 library where the inelastic scattering cross sections and the energy-angular distributions for 238U were replaced by those of the ENDF/B-VI library. The keff values increased by 0.4-0.5%?k/k for the FCA assemblies, by ?0.8%?k/k for ZPPR-9, and the C/E values were improved. It is found that the cause of the increase in the keff values is attributed to the energy distribution for secondary neutrons scattered inelastically by 238U. (author)

289

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Culicoides (Diptera: Ceratopogonidae biting midges are vectors for a diversity of pathogens including bluetongue virus (BTV that generate important economic losses. BTV has expanded its range in recent decades, probably due to the expansion of its main vector and the presence of other autochthonous competent vectors. Although the Canary Islands are still free of bluetongue disease (BTD, Spain and Europe have had to face up to a spread of bluetongue with disastrous consequences. Therefore, it is essential to identify the distribution of biting midges and understand their feeding patterns in areas susceptible to BTD. To that end, we captured biting midges on two farms in the Canary Islands (i to identify the midge species in question and characterize their COI barcoding region and (ii to ascertain the source of their bloodmeals using molecular tools. Methods Biting midges were captured using CDC traps baited with a 4-W blacklight (UV bulb on Gran Canaria and on Tenerife. Biting midges were quantified and identified according to their wing patterns. A 688 bp segment of the mitochondrial COI gene of 20 biting midges (11 from Gran Canaria and 9 from Tenerife were PCR amplified using the primers LCO1490 and HCO2198. Moreover, after selected all available females showing any rest of blood in their abdomen, a nested-PCR approach was used to amplify a fragment of the COI gene from vertebrate DNA contained in bloodmeals. The origin of bloodmeals was identified by comparison with the nucleotide-nucleotide basic alignment search tool (BLAST. Results The morphological identification of 491 female biting midges revealed the presence of a single morphospecies belonging to the Obsoletus group. When sequencing the barcoding region of the 20 females used to check genetic variability, we identified two haplotypes differing in a single base. Comparison analysis using the nucleotide-nucleotide basic alignment search tool (BLAST showed that both haplotypes belong to Culicoides obsoletus, a potential BTV vector. As well, using molecular tools we identified the feeding sources of 136 biting midges and were able to confirm that C. obsoletus females feed on goats and sheep on both islands. Conclusions These results confirm that the feeding pattern of C. obsoletus is a potentially important factor in BTV transmission to susceptible hosts in case of introduction into the archipelago. Consequently, in the Canary Islands it is essential to maintain vigilance of Culicoides-transmitted viruses such as BTV and the novel Schmallenberg virus.

Martínez-de la Puente Josué

2012-07-01

290

When employed with skill and understanding, vector analysis can be a practical and powerful tool. This text develops the algebra and calculus of vectors in a manner useful to physicists and engineers. Numerous exercises (with answers) not only provide practice in manipulation but also help establish students' physical and geometric intuition in regard to vectors and vector concepts.Part I, the basic portion of the text, consists of a thorough treatment of vector algebra and the vector calculus. Part II presents the illustrative matter, demonstrating applications to kinematics, mechanics, and e

Newell, Homer E

2012-01-01

291

During a distribution survey of Simulium damnosum s.l. around the Tukuyu onchocerciasis focus at the northern tip of Lake Malawi/Nyasa (Tanzania), we discovered two new cytoforms of the S. damnosum complex in onchocerciasis-free areas. The Nyika form is related to Simulium thyolense, a vector of onchocerciasis, and can be identified by the new inversion 3L-L on the long arm of chromosome 3. It was found breeding in five rivers in northern Malawi and neighbouring Tanzania and is assumed to be zoophilic. The Njombe form represents a member of the Sanje group of the complex and is characterized by the new diagnostic inversion 2L-35 on chromosome 2. So far, it is only known from around Njombe town in southern Tanzania, where it breeds at remarkably high altitudes. Anthropophily for the Njombe form is well known. The medical importance and systematic position of the new forms within the S. damnosum complex are discussed. PMID:15228490

Krüger, A; Kalinga, A K; Post, R J; Maegga, B T A

2004-07-01

292

Directory of Open Access Journals (Sweden)

Full Text Available In this manuscript, we synthesized the potential non viral vector for gene delivery with proper transfection efficiency and low cytotoxicity. Polyethylenimine (PEI is a well-known cationic polymer which has high positive surface charge for condensing plasmid DNA. However; it is highly cytotoxic in many cell lines because of the high surface charge, non-biodegradability and non-biocompatibility. To enhance PEI biodegradability, the graft copolymer “PEG-g-PEI” was synthesized. To target cancer liver cells, two targeting ligands folic acid and galactose (lactobionic acid which are over expressed on human hepatocyte carcinoma were attached to graft copolymer and “FOL-PEG-g-PEI-GAL” copolymer was synthesized. Composition of this grafted copolymer was characterized using 1H-NMR and FTIR spectra. The molecular weight and zeta potential of this copolymer was compared to PEI. The particle size and zeta potential of FOL-PEG-g-PEI-GAL/DNA complexes at various N/P ratio were measured using dynamic light scattering (DLS. Cytotoxicity of the copolymer was also studied in cultured HepG2 human hepatoblastoma cell line. The FOL-PEG-g-PEI-GAL/DNA complexes at various N/P ratios exhibited no cytotoxicity in HepG2 cell line compared to PEI 25K as a control. The novel copolymer showed enhanced biodegradability in physiological conditions in compared with PEI and targeted cultured HepG2 cells. More importantly, significant transfection efficiency was exhibited in cancer liver cells. Together, our results showed that “FOL-PEG-g-PEI-GAL” nanoparticals could be considered as a useful non-viral vector for targeted gene delivery.

S. Ghiamkazemi

2010-01-01

293

International Nuclear Information System (INIS)

In this manuscript, we synthesized the potential non viral vector for gene delivery with proper transfection efficiency and low cytotoxicity. Polyethylenimine (PEI) is a well-known cationic polymer which has high positive surface charge for condensing plasmid DNA. However; it is highly cytotoxic in many cell lines because of the high surface charge, non-biodegradability and non-biocompatibility. To enhance PEI biodegradability, the graft copolymer PEG-g-PEI was synthesized. To target cancer liver cells, two targeting ligands folic acid and galactose (lactobionic acid) which are over expressed on human hepatocyte carcinoma were attached to graft copolymer and FOL-PEG-g-PEI-GAL copolymer was synthesized. Composition of this grafted copolymer was characterized using 1H-NMR and FTIR spectra. The molecular weight and zeta potential of this copolymer was compared to PEI. The particle size and zeta potential of FOL-PEG-g-PEI-GAL/DNA complexes at various N/P ratio were measured using dynamic light scattering (DLS). Cytotoxicity of the copolymer was also studied in cultured HepG2 human hepatoblastoma cell line. The FOL-PEG-g-PEI-GAL/DNA complexes at various N/P ratios exhibited no cytotoxicity in HepG2 cell line compared to PEI 25K as a control. The novel copolymer showed enhanced biodegradability in physiological conditions in compared with PEI and targeted cultured HepG2 cells. More importantly, significant transfection efficiency was exhibited in cancer liver cells. Togethes exhibited in cancer liver cells. Together, our results showed that FOL-PEG-g-PEI-GAL nanoparticles could be considered as a useful non-viral vector for targeted gene delivery.

294

Little is known about the prevalence and pathogenesis of trypanosomes in Australian monotremes, and few genetic characterisation studies have been conducted with these haemoparasites. During the present investigation, molecular and microscopic methods were used to screen peripheral blood (n=28) and ectoparasites (n=10 adult ticks; n=5 tick nymphs; n=1 leech; and n>500 tick eggs) collected from wild Tasmanian platypuses (Ornithorhynchus anatinus), for the presence of trypanosomatid-specific DNA and/or trypomastigotes. The genes for the small ribosomal subunit RNA (18S rDNA) and glycosomal glyceraldehyde phosphate dehydrogenase (gGAPDH) were amplified and sequenced, prior to conducting phylogenetic analyses. The detection rate of the parasite-specific 18S rDNA in platypus blood was 85.7% (n=24/28), and the leech was also positive at both loci. Microscopically, high parasitaemia and the presence of abundant trypomastigotes, morphologically consistent with Trypanosoma binneyi Mackerras (1959), were observed in the blood films. Phylogenetic analyses at the 18S locus revealed the existence of four trypanosomatid-like genotypes, with variable similarity to two previously-described genotypes of T. binneyi (range of genetic p-distance: 0.0-0.5%). For the gGAPDH locus, for which only one T. binneyi sequence is available in GenBank, three genotypes closely related T. binneyi were identified (range of genetic p-distance: 0.1-0.4%). The leech-derived trypanosome isolate was virtually identical (at the two loci studied) to the other parasites sequenced from infected platypuses; however, the molecular or morphological identification of the leech species was not possible. Although further studies are required, the molecular detection of trypanosomes in an aquatic leech removed from a platypus, suggests the possibility that these haematophagous hirudineans may be a vector for T. binneyi (and closely related genotypes). PMID:25045852

Paparini, Andrea; Macgregor, James; Irwin, Peter J; Warren, Kristin; Ryan, Una M

2014-10-01

295

Toxorhynchites splendens larvae are a natural predator of dengue vector mosquito larvae, Aedes albopictus. This study was carried out to evaluate the predation rate of Tx. splendens third instar larvae on Ae. albopictus larvae in 24 h. Each predator was offered prey at a density between 10 to 50 individuals. Predation rate of Tx. splendens were also tested with two manipulated factors; various types of container and different water volumes. The experiment was evaluated in man-made containers (tin cans, plastic drinking glasses and rubber tires) and natural container (bamboo stumps) which were filled with different water volumes (full, half full, 1/4 full, and 1/8 full). The prey density and the characteristics of the container were found as significant factors which influence the predation rate of Tx. splendens. The predator consumed significantly more prey at higher prey densities (40 and 50 preys) compared to the lowest density (10 preys) (F=3.935, df=4, p=0.008). The results showed significantly higher consumption in horizontal shaped container of rubber tire than in vertical shape of bamboo stumps (F=3.100, df=3, p=0.029). However, the water volume had no significant effect on predation rate of Tx. splendens (F=1.736, df=3, p=0.162). We generally suggest that Tx. splendens is best to be released in discarded tires or any other containers with horizontal shape design with wide opening since Tx. splendens can become more effective in searching prey in this type of container design. This predator is also a suitable biocontrol candidates to be introduced either in wet and dry seasons in Malaysia. PMID:24862057

Mohamad, N; Zuharah, W F

2014-03-01

296

Toxic microalgae outbreaks have caused significant economic losses in the Mexican aquaculture industry. Blooms that involve PSP and NSP phycotoxins are two of the most dangerous, causing harmful effects to the environment, economy and public health. The exact metabolic mechanism of these toxins in shrimp still remains unknown. Because shrimp consume microalgae their edible tissues are clearly possible vectors for human toxic syndrome. This study examined and verified the toxicological effects for white leg shrimp (Litopenaeus vannamei) exposed to different cell densities of Gymnodinium catenatum and Karenia brevis. Acute assays demonstrated good survival rates of shrimp at low densities of dinoflagellates (10(3) cell/L), while mortality and abnormal behavior were observed with higher densities (>10(4) cell/L). Chronic assays showed significant differences in survival rates, percentage of feed and weight gain of organisms exposed to the dinoflagellates with respect to controls. Furthermore, PSP and NSP toxins were detected in all the edible tissues. Gastric glands and muscle retained toxins for a longer period of time compared to other tissues, even after a depuration period. Histology damages were observed in the heart, gastric gland and brain. This study strongly supports that shrimp represent a potential risk for humans as unconventional vectors of phycotoxins. PMID:19028514

Pérez Linares, Jesús; Ochoa, José Luis; Gago Martínez, Ana

2009-02-01

297

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We present a new approximation scheme for the centrifugal term to obtain a quasi-exact analytical bound state solution within the framework of the position-dependent effective mass radial Klein-Gordon equation with the scalar and vector Hulthen potentials in any arbitrary D dimension and orbital angular momentum quantum numbers l. The Nikiforov-Uvarov (NU) method is used in the calculations. The relativistic real energy levels and corresponding eigenfunctions for the bound states with different screening parameters have been given in a closed form. It is found that the solutions in the case of constant mass and in the case of s-wave (l=0) are identical with the ones obtained in the literature.

Ikhdair, Sameer M [Department of Physics, Near East University, Nicosia, North Cyprus (Turkey); Sever, Ramazan [Department of Physics, Middle East Technical University, 06800 Ankara (Turkey)], E-mail: sikhdair@neu.edu.tr, E-mail: sever@metu.edu.tr

2009-03-15

298

Huanglongbing (HLB) is a severe citrus (Citrus spp.) disease associated with the bacteria genus Candidatus Liberibacter, detected in Brazil in 2004. Another bacterium was found in association with HLB symptoms and characterized as a phytoplasma belonging to the 16SrIX group. The objectives of this study were to identify potential leafhopper vectors of the HLB-associated phytoplasma and their host plants. Leafhoppers were sampled every other week for 12 mo with sticky yellow cards placed at two heights (0.3 and 1.5 m) in the citrus tree canopy and by using a sweep net in the ground vegetation of two sweet orange, Citrus sinensis (L.) Osbeck, groves infected by the HLB-phytoplasma in São Paulo state. Faunistic analyses indicated one Agalliinae (Agallia albidula Uhler) and three Deltocephalinae [Balclutha hebe (Kirkaldy), Planicephalus flavicosta (Stål), and Scaphytopius (Convelinus) marginelineatus (Stål)] species, as the most abundant and frequent leafhoppers (Hemiptera: Cicadellidae). Visual observations indicated an association of leafhopper species with some weeds and the influence of weed species composition on leafhopper abundance in low-lying vegetation. S. marginelineatus and P. flavicosta were more frequent on Sida rhombifolia L. and Althernantera tenella Colla, respectively, whereas A. albidula was observed more often on Conyza bonariensis (L.) Cronq. and B. hebe only occurred on grasses. DNA samples of field-collected S. marginelineatus were positive by polymerase chain reaction and sequencing tests for the presence of the HLB-phytoplasma group, indicating it as a potential vector. The association of leafhoppers with their hosts may be used in deciding which management strategies to adopt against weeds and diseases in citrus orchards. PMID:22606800

Marques, R N; Teixeira, D C; Yamamoto, P T; Lopes, J R S

2012-04-01

299

Elementary Vectors, Third Edition serves as an introductory course in vector analysis and is intended to present the theoretical and application aspects of vectors. The book covers topics that rigorously explain and provide definitions, principles, equations, and methods in vector analysis. Applications of vector methods to simple kinematical and dynamical problems; central forces and orbits; and solutions to geometrical problems are discussed as well. This edition of the text also provides an appendix, intended for students, which the author hopes to bridge the gap between theory and applicat

Wolstenholme, E Œ

1978-01-01

300

The spatial patterns of Photosynthetically Active Radiation (PAR) under forest canopies, including both its mean and spatial variation, are critical factors that determine numerous ecophysiological processes in plant ecosystems. Though numerous models have been developed that can accurately simulate PAR transmission through plant canopies, Beer's law remains the primary model used in ecological models to describe PAR transmission through plant canopies due to the fact that the more accurate models are too complicated to be used operationally. This study developed a simple and computationally efficient model to simulate both the Mean and Variation of PAR (MVP) under the forest canopy. The model provides a careful description of the effects of gaps on the variable light environment under forest canopy, while it simplifies the simulation of multiple scattering of photons. The model assumes that a forest canopy is composed of individual crowns distributed within upper and lower boundaries with two types of gaps: the between- and within-crown gaps. The inputs to the model are canopy structural parameters, including canopy depth, tree count density, tree crown shape, and foliage area volume density (m2/m3, leaf areas per unit crown volume). The between-crown gaps are simulated with geometric optics, and the within-crown gaps are described by Beer's law. The model accounts for the covariance of PAR in space through time, making it possible to simulate both instantaneous variation of PAR and variation of daily accumulated PAR. Validation with observed PAR using ten quantum sensors under the Old Black Spruce stand at the Southern Study Area of the BOREAS project indicates the model captures the mean and variation of PAR under forest canopy reasonably well. The model is simple enough that it can be used by other ecological models, such as ecosystem dynamics and carbon budget models. Further validation and testing of the model with other types forest are needed in the future.

Song, C.; Band, L. E.

2003-12-01

301

International Nuclear Information System (INIS)

The cause of the abnormal power change phenomenon of Phenix core is studied under the assumption that a negative reactivity insertion is induced by a gas blow into the control rod assemblies. The size and layout of the core analyzed are set to simulate the Phenix core while material compositions of the assemblies are assumed to be a typical MOX fuel core and the control rod channel is assumed to be a simple sodium plenum zone at intact. The calculation has been conducted by using three-dimensional continuation energy Monte Carlo code MVP with JENDL-3.3 library so that the neutron moderation and leakage through the void channel can be evaluated exactly. The result of the analysis shows the negative void reactivity is about -80 cents when the sodium below the level of 1/3 of core height from the core bottom of the seven control assemblies including the center shutdown system is voided while it is about -1 cents when the sodium between the core bottom to the core top is voided in the same assemblies. The void reactivity for the region above the level of 2/3 of core height is again about -80 cents. The negative reactivity of -80 cents is consistent to the power decrease of about 40 % at the beginning of the event if zero-power reactor model can be applied to the transient of this phenomenon. The successive power swing observed can be explained by the reactivity change if the gas flows up through the control assemblies in which the cross sectional area of the gas is reduce cross sectional area of the gas is reduced by a half at the upper level of the assembly due to the absorber pins. (authors)

302

There is currently considerable interest and practical progress in using the endosymbiotic bacteria Wolbachia as a vector control agent for human vector-borne diseases. Such vector control strategies may require the introduction of multiple, different Wolbachia strains into target vector populations, necessitating the identification and characterization of appropriate endosymbiont variants. Here, we report preliminary characterization of wFlu, a native Wolbachia from the neotropical mosquito ...

Baton, Luke Anthony; Pacido?nio, Etiene Casagrande; Gonc?alves, Daniela Da Silva; Moreira, Luciano Andrade

2013-01-01

303

The Maremma Plain (central Italy) was hyper-endemic for malaria until the mid-20th century, when a national campaign for malaria elimination drastically reduced the presence of the main vector Anopheles labranchiae Falleroni. However, the introduction of rice cultivation over 30 yr ago has led to an increase in the An. labranchiae population and concern over possible malaria reemergence. We studied the impact of anthropogenic environmental changes on the abundance and distribution of An. labranchiae in Maremma, focusing on rice fields, the main breeding sites. Adults and larvae were collected in three main areas with diverse ecological characteristics. Data were collected on human activity, land use, and seasonal climatic and demographic variations. We also interviewed residents and tourists regarding their knowledge of malaria. Our findings showed that the most important environmental changes have occurred along the coast; An. labranchiae foci are present throughout the area, with massive reproduction strictly related to rice cultivation in coastal areas. Although the abundance of this species has drastically decreased over the past 30 yr, it remains high and, together with climatic conditions and the potential introduction of gametocyte carriers, it may represent a threat for the occurrence of autochthonous malaria cases. Our findings suggest the need for the continuous monitoring of An. labranchiae in the study area. In addition to entomological surveillance, more detailed knowledge of human-induced environmental changes is needed, so as to have a more complete database that can be used for vector-control plans and for properly managing emergencies related to autochthonous introduced cases. PMID:22897043

Boccolini, D; Toma, L; Di Luca, M; Severini, F; Cocchi, M; Bella, A; Massa, A; Mancini Barbieri, F; Bongiorno, G; Angeli, L; Pontuale, G; Raffaelli, I; Fausto, A M; Tamburro, A; Romi, R

2012-07-01

304

A study of West Nile virus (WNV) ecology was conducted in St. Tammany Parish, Louisiana, from 2002 to 2004. Mosquitoes were collected weekly throughout the year using Centers for Disease Control and Prevention (CDC) light traps placed at 1.5 and 6 m above the ground and gravid traps. A total of 379,466 mosquitoes was collected. WNV was identified in 32 pools of mosquitoes comprising four species; 23 positive pools were from Culex nigripalpus collected during 2003. Significantly more positive pools were obtained from Cx. nigripalpus collected in traps placed at 6 m than 1.5 m that year, but abundance did not differ by trap height. In contrast, Cx. nigripalpus abundance was significantly greater in traps placed at 6 m in 2002 and 2004. Annual temporal variation in Cx. nigripalpus peak seasonal abundance has important implications for WNV transmission in Louisiana. One WNV-positive pool, from Cx. erraticus, was collected during the winter of 2004, showing year-round transmission. The potential roles of additional mosquito species in WNV transmission in southeastern Louisiana are discussed. Disclaimer: The opinions expressed in this article are the opinions of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention. This article has been peer reviewed and approved for publication consistent with U.S. Geological Survey Fundamental Science Practices (http//pubs.usgs.gov/circ/1367/). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Godsey, Marvin S., Jr.; King, Raymond J.; Burkhalter, Kristen; Delorey, Mark; Colton, Leah; Charnetzky, Dawn; Sutherland, Genevieve; Ezenwa, Vanessa O.; Wilson, Lawrence A.; Coffey, Michelle; Milheim, Lesley E.; Taylor, Viki G.; Palmisano, Charles; Wesson, Dawn M.; Guptill, Stephen C.

2013-01-01

305

International Nuclear Information System (INIS)

The recently reported curl-free vector potential observation (Varma et al 2012 Eur. Phys. J. D 66 38) in relation to a system of charged particles in a magnetic field points to the existence of a new state of the electron - a quantum modulated state - which arises through a scattering-induced transition across Landau levels. This quantum modulated state has been shown to account for some very unusual effects on the macro-scale, which are distinct from the ones which can be understood in terms of a ‘classical electron’ and also from the ones which can be understood in terms of a ‘quantum electron’ on the micro-scale characterized by the Planck quantum. This quantum modulated state has been shown to account for the observation of a static curl-free vector potential on the macro-scale alluded to above, as well as other matter wave manifestations on the macro-scale. The macro-scale curl-free vector potential observation differs fundamentally from the corresponding micro-scale effect - the well-known Aharonov-Bohm effect. These two effects - on the macro-scale and the macro-scale - are compared and contrasted to each other here in their manner of detection of the static curl-free vector potential. Such a comparative study helps gain a deeper understanding of the nature of the quantum modulated state and the macro-scale matter wave it represents.

306

Energy Technology Data Exchange (ETDEWEB)

The coupled nonlinear volatility and option pricing model presented recently by Ivancevic is investigated, which generates a leverage effect, i.e., stock volatility is (negatively) correlated to stock returns, and can be regarded as a coupled nonlinear wave alternative of the Black–Scholes option pricing model. In this Letter, we analytically propose vector financial rogue waves of the coupled nonlinear volatility and option pricing model without an embedded w-learning. Moreover, we exhibit their dynamical behaviors for chosen different parameters. The vector financial rogue wave (rogon) solutions may be used to describe the possible physical mechanisms for the rogue wave phenomena and to further excite the possibility of relative researches and potential applications of vector rogue waves in the financial markets and other related fields. -- Highlights: ? We investigate the coupled nonlinear volatility and option pricing model. ? We analytically present vector financial rogue waves. ? The vector financial rogue waves may be used to describe the extreme events in financial markets. ? This results may excite the relative researches and potential applications of vector rogue waves.

Yan, Zhenya, E-mail: zyyan@mmrc.iss.ac.cn [Key Laboratory of Mathematics Mechanization, Institute of Systems Science, AMSS, Chinese Academy of Sciences, Beijing 100190 (China)

2011-11-21

307

International Nuclear Information System (INIS)

The coupled nonlinear volatility and option pricing model presented recently by Ivancevic is investigated, which generates a leverage effect, i.e., stock volatility is (negatively) correlated to stock returns, and can be regarded as a coupled nonlinear wave alternative of the Black–Scholes option pricing model. In this Letter, we analytically propose vector financial rogue waves of the coupled nonlinear volatility and option pricing model without an embedded w-learning. Moreover, we exhibit their dynamical behaviors for chosen different parameters. The vector financial rogue wave (rogon) solutions may be used to describe the possible physical mechanisms for the rogue wave phenomena and to further excite the possibility of relative researches and potential applications of vector rogue waves in the financial markets and other related fields. -- Highlights: ? We investigate the coupled nonlinear volatility and option pricing model. ? We analytically present vector financial rogue waves. ? The vector financial rogue waves may be used to describe the extreme events in financial markets. ? This results may excite the relative researches and potential applications of vector rogue waves.

308

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction We analyzed the vertical and monthly distributions of culicid species in the gallery forest of Brasília National Park, with an emphasis on the potential vectors of yellow fever (YF). Methods Between September 2010 and August 2011, mosquitoes were captured on the ground and in the ca [...] nopy of the forest for five consecutive days per month, from nine to 15 hours. The mosquitoes were examined to verify natural infection with flaviviruses by isolation in Aedes albopictus Skuse, 1864 cells followed by indirect immunofluorescence. Results We identified 2,677 culicids distributed in 29 species. Most of the mosquitoes were captured at ground level (69%) during the rainy season (86%). The most abundant species were Sabethes (Sabethes) albiprivus Theobald, 1903; Limatus durhamii Theobald, 1901; Haemagogus (Conopostegus) leucocelaenus Dyar & Shannon, 1924; Haemagogus (Haemagogus) janthinomys Dyar, 1921; Aedes (Ochlerotatus) scapularis Rondani, 1848; Psorophora (Janthinosoma) ferox Von Humboldt, 1819; and Aedes (Ochlerotatus) serratus Theobald, 1901. Limatus durhamii, Limatus durhamii, Psorophora ferox, Aedes scapularis and Aedes serratus showed significant differences (p

Ana Raquel, Lira-Vieira; Rodrigo, Gurgel-Goncalves; Israel Martins, Moreira; Maria Amelia Cavalcanti, Yoshizawa; Milton Lopes, Coutinho; Paulo Sousa, Prado; Jorge Lopes de, Souza; Antonio Jesus de Melo, Chaib; Joao Suender, Moreira; Cleudson Nery de, Castro.

2013-10-15

309

The objective of the present study was to determine the potential for house flies (Musca domestica L.) (Diptera: Muscidae) to harbour the avian influenza (AI) H5N1 virus. Laboratory-reared flies were experimentally fed with a mixture containing the AI virus. Exposed flies were washed with brain-heart infusion broth and followed by 70% alcohol before preparation of whole fly homogenate. The homogenate was inoculated into six 10-day-old embryonated chicken eggs (ECEs). Allantoic fluids were collected to determine the virus using the haemagglutination (HA) test, reverse transcription-polymerase chain reaction (RT-PCR) or quantitative real-time RT-PCR (RRT-PCR). In the first experiment, ECEs that were inoculated with the 50 AI virus exposed fly homogenates died within 48 h and HA and RT-PCR were positive for AI virus. In the second experiment, ECEs that were inoculated with only one fly died with positive HA test and RT-PCR. In the last experiment, a group of exposed flies was collected at 0, 6, 12, 24, 36, 48, 72 and 96 h post-exposure. Fly homogenates of each time point were tested by virus titration in ECEs and RRT-PCR. Virus titres declined in relation to exposure time. Furthermore, RRT-PCR results were positive at any time point. The present study shows that the flies may harbour the AI virus and could act as a mechanical vector of the AI virus. PMID:21118285

Wanaratana, S; Panyim, S; Pakpinyo, S

2011-03-01

310

In recent years, almond leaf scorch (ALS) disease, caused by Xylella fastidiosa (Xf) has reemerged as a serious disease threat to almond production areas throughout California's San Joaquin Valley (SJV). The vector(s) of ALS strains of Xf, however, have not been as well documented and research is un...

311

A vector comprising a filamentous phage sequence containing a first copy of filamentous phage gene X and other sequences necessary for the phage to propagate is disclosed. The vector also contains a second copy of filamentous phage gene X downstream from a promoter capable of promoting transcription in a bacterial host. In a preferred form of the present invention, the filamentous phage is M13 and the vector additionally includes a restriction endonuclease site located in such a manner as to substantially inactivate the second gene X when a DNA sequence is inserted into the restriction site.

Guilfoyle, Richard A. (Madison, WI); Smith, Lloyd M. (Madison, WI)

1994-01-01

312

Abstract Background Culex spp. mosquitoes are considered to be the most important vectors of West Nile virus (WNV) detected in at least 34 species of mosquitoes in the United States. In North America, Culex pipiens pipiens, Culex pipiens quinquefasciatus, and Culex tarsalis are all competent vectors of WNV, which is considered to be enzootic in the United States and has also been detected in equines and birds in many states of Mexico and in humans in Nuevo Leon. There is potential for WNV to ...

Diaz-Perez Alfonso; Camacho-Nuez Minerva; Padilla-Viveros America A; Martinez-Munoz Jorge P; Moore Chester G; Perez-Ramirez Gerardo; Bolling Bethany G; Diaz-Badillo Alvaro; Beaty Barry J; de Lourdes Munoz Maria

2011-01-01

313

Insecticide resistance and vector control.

Insecticide resistance has been a problem in all insect groups that serve as vectors of emerging diseases. Although mechanisms by which insecticides become less effective are similar across all vector taxa, each resistance problem is potentially unique and may involve a complex pattern of resistance foci. The main defense against resistance is close surveillance of the susceptibility of vector populations. We describe the mechanisms of insecticide resistance, as well as specific instances of ...

Brogdon, W. G.; Mcallister, J. C.

1998-01-01

314

Reciprocal vectors and barycentric coordinates are well-established concepts in various scientific fields, where lattices and grids are essential, e.g., in solid state physics, crystallography, in the numerical analysis of partial differential equations using finite elements, and also in computer graphics and visualisation. In preparation of the Cluster mission, Chanteur [1998] in Chapter 14 of ISSI SR-001 adopted reciprocal vectors to construct estimators for spatial derivatives from four-point measurements, to perform error analysis, and to write down the spatial aliasing condition for four-point wave analysis techniques in a very transparent form. Reciprocal vectors also entered the study on the ac- curacy of plasma moment derivatives, described in Chapter 17 of ISSI SR-001 [Vogt and Paschmann, 1998]. As will be shown below, by using the least squares approach presented in Chapter 12 of ISSI SR-001 [Harvey, 1998], reciprocal vectors are a convenient means in discontinuity analysis to express boundary parameters in terms of crossing times. This chapter is intended to provide a conceptual introduction to reciprocal vectors, and to emphasise their importance for the analysis of data from the Cluster spacecraft mission. It is organised as follows: The crossing times approach to boundary analysis is presented in Section 4.2 as a way to motivate the use of reciprocal vectors; some of their most important properties are briefly addressed in Section 4.3; then Section 4.4 deals with various aspects of the spatial gradient reconstruction problem; magnetic curvature estimation is reviewed in Section 4.5, while Section 4.6 contains a discussion on the errors of boundary analysis and curvature estimation. Finally, in Section 4.7 we suggest a way to generalise the reciprocal vector concept to cases where the number of spacecraft, N, is not four.

Vogt, Joachim; Paschmann, Gotz; Chanteur, Gérard

315

International Nuclear Information System (INIS)

The authors have previously described a defective herpes simplex virus (HSV-1) vector system that permits that introduction of virtually any gene into nonmitotic cells. pHSVlac, the prototype vector, stably expresses Escherichia coli ?-galactosidase from a constitutive promoter in many human cell lines, in cultured rat neurons from throughout the nervous system, and in cells in the adult rat brain. HSV-1 vectors expressing other genes may prove useful for studying neuronal physiology or performing human gene therapy for neurological diseases, such as Parkinson disease or brain tumors. A HSV-1 temperature-sensitive (ts) mutant, ts K, has been used as helper virus; ts mutants revert to wild type. In contrast, HSV-1 deletion mutants essentially cannot revert to wild type; therefore, use of a deletion mutant as helper virus might permit human gene therapy with HSV-1 vectors. They now report an efficient packaging system for HSV-1 VECTORS USING A DELETION MUTANT, d30EBA, as helper virus; virus is grown on the complementing cell line M64A. pHSVlac virus prepared using the deletion mutant packaging system stably expresses ?-galactosidase in cultured rat sympathetic neurons and glia. Both D30EBA and ts K contain a mutation in the IE3 gene of HSV-1 strain 17 and have the same phenotype; therefore, changing the helper virus from ts K to D30EBA does not alter the host range or other properties of the HSV-1 vector system

316

Weak energy dependence of EBT gafchromic film dose response in the 50 kVp-10 MVp X-ray range

International Nuclear Information System (INIS)

The energy dependence of the dose response of EBT Gafchromic film is assessed over a broad energy range, from superficial to megavoltage X-rays. The film is auto-developing and sensitive, it provides accurate dose assessment of low doses (about 1-2 Gy) used in radiotherapy. The energy dependence of the response of EBT film was found to be very weak: the variations do not exceed 10% over the range from 50 kVp to 10 MVp X-rays. By contrast, variations of the response of Gafchromic HS film are as big as 30% over the same range, and variations of the response of Radiographic film exceed one order of magnitude. This weak dependence provides significantly higher accuracy of dose measurements under conditions of varying spectral quality of X-ray beams, which are common in radiation therapy

317

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Larval mosquito habitats of potential malaria vectors and related species of Anopheles from three provinces (Gyeonggi, Gyeongsangbuk, Chungcheongbuk Provinces of the Republic of Korea were surveyed in 2007. This study aimed to determine the species composition, seasonal occurrence and distributions of Anopheles mosquitoes. Satellite derived normalized difference vegetation index data (NDVI was also used to study the seasonal abundance patterns of Anopheles mosquitoes. Methods Mosquito larvae from various habitats were collected using a standard larval dipper or a white plastic larval tray, placed in plastic bags, and were preserved in 100% ethyl alcohol for species identification by PCR and DNA sequencing. The habitats in the monthly larval surveys included artificial containers, ground depressions, irrigation ditches, drainage ditches, ground pools, ponds, rice paddies, stream margins, inlets and pools, swamps, and uncultivated fields. All field-collected specimens were identified to species, and relationships among habitats and locations based on species composition were determined using cluster statistical analysis. Results In about 10,000 specimens collected, eight species of Anopheles belonging to three groups were identified: Hyrcanus Group - Anopheles sinensis, Anopheles kleini, Anopheles belenrae, Anopheles pullus, Anopheles lesteri, Anopheles sineroides; Barbirostris Group - Anopheles koreicus; and Lindesayi Group - Anopheles lindesayi japonicus. Only An. sinensis was collected from all habitats groups, while An. kleini, An. pullus and An. sineroides were sampled from all, except artificial containers. The highest number of Anopheles larvae was found in the rice paddies (34.8%, followed by irrigation ditches (23.4%, ponds (17.0%, and stream margins, inlets and pools (12.0%. Anopheles sinensis was the dominant species, followed by An. kleini, An. pullus and An. sineroides. The monthly abundance data of the Anopheles species from three locations (Munsan, Jinbo and Hayang were compared against NDVI and NDVI anomalies. Conclusion The species composition of Anopheles larvae varied in different habitats at various locations. Anopheles populations fluctuated with the seasonal dynamics of vegetation for 2007. Multi-year data of mosquito collections are required to provide a better characterization of the abundance of these insects from year to year, which can potentially provide predictive capability of their population density based on remotely sensed ecological measurements.

Foley Desmond H

2010-02-01

318

This brief undergraduate-level text by a prominent Cambridge-educated mathematician explores the relationship between algebra and geometry. An elementary course in plane geometry is the sole requirement for Gilbert de B. Robinson's text, which is the result of several years of teaching and learning the most effective methods from discussions with students. Topics include lines and planes, determinants and linear equations, matrices, groups and linear transformations, and vectors and vector spaces. Additional subjects range from conics and quadrics to homogeneous coordinates and projective geom

Robinson, Gilbert de B

2013-01-01

319

Effect of potential on bismuth telluride thin film growth by electrochemical atomic layer epitaxy

International Nuclear Information System (INIS)

In the present study, bismuth telluride compound thin film was grown by means of electrochemical atomic layer epitaxy (ECALE) with an automated thin layer flow cell deposition system. The dependence of the Bi and Te deposition potentials on Pt electrode was studied. Because developing a contact potential between the substrate and the growing semiconductor, the deposition potential adjustment is necessary for the first 30 or more cycles of each component. The dependence of the deposit as a function of the deposition potential adjustment slope has been investigated. The results show that an excess elemental Bi existed at a slope of -2 mV/p (p indicates per cycle), indicating that this is a lack of deposition at the potential. Single-phase Bi2Te3 compound could be obtained between -4 and -6 mV/p. Bi2Te3 and Bi4Te3 coexistence is observed at a slope of -10 mV/p. The EDS data indicates that the stoichiometry of compound is consistent with XRD result. SEM studies show that the deposits are inhomogeneous and have an micron sized particles morphology

320

Malaria and dengue are the two most important vector-borne human diseases caused by mosquito vectors Anopheles stephensi and Aedes aegypti, respectively. Of the various strategies adopted for eliminating these diseases, controlling of vectors through herbs has been reckoned as one of the important measures for preventing their resurgence. Artemisia annua leaf chloroform extract when tried against larvae of A. stephensi and A. aegypti has shown a strong larvicidal activity against both of these vectors, their respective LC50 and LC90 values being 0.84 and 4.91 ppm for A. stephensi and 0.67 and 5.84 ppm for A. aegypti. The crude extract when separated through column chromatography using petroleum ether-ethyl acetate gradient (0-100%) yielded 76 fractions which were pooled into three different active fractions A, B and C on the basis of same or nearly similar R f values. The aforesaid pooled fractions when assayed against the larvae of A. stephensi too reported a strong larvicidal activity. The respective marker compound purified from the individual fractions A, B and C, were Artemisinin, Arteannuin B and Artemisinic acid, as confirmed and characterized through FT-IR and NMR. This is our first report of strong mortality of A. annua leaf chloroform extract against vectors of two deadly diseases. This technology can be scaled up for commercial exploitation. PMID:24158647

Sharma, Gaurav; Kapoor, Himanshi; Chopra, Madhu; Kumar, Kaushal; Agrawal, Veena

2014-01-01

321

Translational errors are necessary so as to allow gene expression in various organisms. In retroviruses, synthesis of pol gene products necessitates either readthrough of a stop codon or frameshifting. Here we present an experimental system that permits quantification of translational errors in vivo. It consists of a family of expression vectors carrying different mutated versions of the luc gene as reporter. Mutations include both an in-frame stop codon and 1-base-pair deletions that require readthrough or frameshift, respectively, to give rise to an active product. This system is sensitive enough to detect background errors in mammalian cells. In addition, one of the vectors contains two unique cloning sites that make it possible to insert any sequence of interest. This latter vector was used to analyse the effect of a DNA fragment, proposed to be the target of high level slippage at the gag-pol junction of HIV. The effect of paromomycin and kasugamycin, two antibiotics known to influence translational ambiguity, was also tested in cultured cells. The results indicate that paromomycin diversely affects readthrough and frameshifting, while kasugamycin had no effect. This family of vectors can be used to analyse the influence of structural and external factors on translational ambiguity in both mammalian cells and bacteria. PMID:2087598

Cassan, M; Berteaux, V; Angrand, P O; Rousset, J P

1990-01-01

322

Vector inflation by kinetic coupled gravity

Vector inflation is a newly established model where inflation is driven by non-minimally coupled massive vector fields with a potential term. This model is similar to the model of chaotic inflation with scalar fields, except that for vector fields the isotropy of expansion is achieved either by considering a triplet of orthogonal vector fields or $N$ randomly oriented independent vector fields. We introduce a new version of vector inflation where the vector field has no potential term but is non-minimally coupled to gravity through the kinetic term. The non-minimal coupling is established by introducing the Einstein tensor besides the metric tensor within the kinetic term of the vector field.

Darabi, F

2014-01-01

323

Adeno-associated virus vector integration junctions.

Vectors derived from adeno-associated virus (AAV) have the potential to stably transduce mammalian cells by integrating into host chromosomes. Despite active research on the use of AAV vectors for gene therapy, the structure of integrated vector proviruses has not previously been analyzed at the DNA sequence level. Studies on the integration of wild-type AAV have identified a common site-specific integration locus on human chromosome 19; however, most AAV vectors do not appear to integrate at...

Rutledge, E. A.; Russell, D. W.

1997-01-01

324

International Nuclear Information System (INIS)

In May 2010, JENDL-4.0 was released from Japan Atomic Energy Agency as the updated Japanese Nuclear Data Library. It was processed by the nuclear data processing system LICEM and an arbitrary-temperature neutron cross section library MVPlib-nJ40 was produced for the neutron and photon transport calculation code MVP based on the continuous-energy Monte Carlo method. The library contains neutron cross sections for 406 nuclides on the free gas model, thermal scattering cross sections, and cross sections of pseudo fission products for burn-up calculations with MVP. Criticality benchmark calculations were carried out with MVP and MVPlib-nJ40 for about 1,000 cases of critical experiments stored in the hand book of International Criticality Safety Benchmark Evaluation Project (ICSBEP), which covers a wide variety of fuel materials, fuel forms, and neutron spectra. We report all comparison results (C/E values) of effective neutron multiplication factors between calculations and experiments to give a validation data for the prediction accuracy of JENDL-4.0 for criticalities. (author)

325

Chagas disease is caused by the parasite Trypanosoma cruzi, which is transmitted to humans by blood-sucking triatomine insects. This disease is endemic throughout Mexico and Central and South America, but only a few autochthonous cases have been reported in the United States, despite the fact that infected insects readily invade houses and feed on humans. Competent vectors defecate during or shortly after feeding so that infective feces contact the host. We thus studied the feeding and defeca...

Reisenman, Carolina E.; Gregory, Teresa; Guerenstein, Pablo G.; Hildebrand, John G.

2011-01-01

326

Scientific Electronic Library Online (English)

Full Text Available The future dispersal of onchocerciasis in Ecuador is dependent on the distribution of cytotypes of the vector species complex Simulium exiguum. Over the last 14 years, collections of larvae have been made from over 25 rivers, between 80-1600 m altitude, from various sites on both sides of the Andes. [...] Analysis of larval polytene chromosomes was used to determine the distributions of each cytotype. On the western side of the Andes, the Cayapa cytotype (the only cytotype directly incriminated as a vector) has a distribution from Santo Domingo de los Colorados northwards. The Quevedo and Bucay cytotypes occur from Santo Domingo de los Colorados southwards. On the eastern side of the Andes, the Aguarico cytotype occurs in the Rio Aguarico and a new cytotype is present in the tributaries of the Rio Napo. Whether the disease will spread south of Santo Domingo and on the eastern side of the Andes depends on vector capacity of the cytotypes and the dispersal patterns of individuals infected with onchocerciasis. At present the Aguarico, Bucay and Quevedo cytotypes are known to be efficient hosts, but their biting preferences and biting densities have not yet been evaluated

M, Charalambous; AJ, Shelley; M, Arzube.

1997-03-01

327

The potato psyllid (PoP) Bactericera cockerelli (Sulc) and Asian citrus psyllid (ACP) Diaphorina citri Kuwayama are the insect vectors of the fastidious plant pathogen, Candidatus Liberibacter solanacearum (CLso) and Ca. L. asiaticus (CLas), respectively. CLso causes Zebra chip disease of potato and vein-greening in solanaceous species, whereas, CLas causes citrus greening disease. The reliance on insecticides for vector management to reduce pathogen transmission has increased interest in alternative approaches, including RNA interference to abate expression of genes essential for psyllid-mediated Ca. Liberibacter transmission. To identify genes with significantly altered expression at different life stages and conditions of CLso/CLas infection, cDNA libraries were constructed for CLso-infected and -uninfected PoP adults and nymphal instars. Illumina sequencing produced 199,081,451 reads that were assembled into 82,224 unique transcripts. PoP and the analogous transcripts from ACP adult and nymphs reported elsewhere were annotated, organized into functional gene groups using the Gene Ontology classification system, and analyzed for differential in silico expression. Expression profiles revealed vector life stage differences and differential gene expression associated with Liberibacter infection of the psyllid host, including invasion, immune system modulation, nutrition, and development. PMID:25436509

Fisher, Tonja W; Vyas, Meenal; He, Ruifeng; Nelson, William; Cicero, Joseph M; Willer, Mark; Kim, Ryan; Kramer, Robin; May, Greg A; Crow, John A; Soderlund, Carol A; Gang, David R; Brown, Judith K

2014-01-01

328

Directory of Open Access Journals (Sweden)

Full Text Available The potato psyllid (PoP Bactericera cockerelli (Sulc and Asian citrus psyllid (ACP Diaphorina citri Kuwayama are the insect vectors of the fastidious plant pathogen, Candidatus Liberibacter solanacearum (CLso and Ca. L. asiaticus (CLas, respectively. CLso causes Zebra chip disease of potato and vein-greening in solanaceous species, whereas, CLas causes citrus greening disease. The reliance on insecticides for vector management to reduce pathogen transmission has increased interest in alternative approaches, including RNA interference to abate expression of genes essential for psyllid-mediated Ca. Liberibacter transmission. To identify genes with significantly altered expression at different life stages and conditions of CLso/CLas infection, cDNA libraries were constructed for CLso-infected and -uninfected PoP adults and nymphal instars. Illumina sequencing produced 199,081,451 reads that were assembled into 82,224 unique transcripts. PoP and the analogous transcripts from ACP adult and nymphs reported elsewhere were annotated, organized into functional gene groups using the Gene Ontology classification system, and analyzed for differential in silico expression. Expression profiles revealed vector life stage differences and differential gene expression associated with Liberibacter infection of the psyllid host, including invasion, immune system modulation, nutrition, and development.

Tonja W. Fisher

2014-11-01

329

International Nuclear Information System (INIS)

For accurate inventory estimation of long-lived fission products in LWR spent fuels, a new burn-up chain model was developed, and the latest nuclear data were employed for neutron cross sections, fission yields, half-lives, and so on. Most of them are taken from JENDL-4.0. MVP-BURN with the latest nuclear data was applied to three post irradiation examinations including inventory measurements of 79Se, 99Tc, 126Sn and 135Cs. One of them is new measurements obtained by JAEA. From the PIE analyses, it is found that the new measurements by JAEA are consistent with the other PIE data obtained by different laboratory with different techniques. It is also confirmed that the present calculation results show good agreements with experimental ones for 79Se and 135Cs within about 10%. In contrast, amounts of 99Tc and 126Sn are overestimated by about 50%. These discrepancies are likely due to the effect of insoluble residue in the measurements and/or errors of fission yields in the analyses. (author)

330

Bluetongue virus (BTV) is an economically important Orbivirus transmitted by biting midges to domestic and wild ruminants. The need for new vaccines has been highlighted by the occurrence of repeated outbreaks caused by different BTV serotypes since 1998. The major group-reactive antigen of BTV, VP7, is conserved in the 26 serotypes described so far, and its role in the induction of protective immunity has been proposed. Viral-based vectors as antigen delivery systems display considerable promise as veterinary vaccine candidates. In this paper we have evaluated the capacity of the BTV-2 serotype VP7 core protein expressed by either a non-replicative canine adenovirus type 2 (Cav-VP7 R0) or a leporipoxvirus (SG33-VP7), to induce immune responses in sheep. Humoral responses were elicited against VP7 in almost all animals that received the recombinant vectors. Both Cav-VP7 R0 and SG33-VP7 stimulated an antigen-specific CD4+ response and Cav-VP7 R0 stimulated substantial proliferation of antigen-specific CD8+ lymphocytes. Encouraged by the results obtained with the Cav-VP7 R0 vaccine vector, immunized animals were challenged with either the homologous BTV-2 or the heterologous BTV-8 serotype and viral burden in plasma was followed by real-time RT-PCR. The immune responses triggered by Cav-VP7 R0 were insufficient to afford protective immunity against BTV infection, despite partial protection obtained against homologous challenge. This work underscores the need to further characterize the role of BTV proteins in cross-protective immunity. PMID:25364822

Bouet-Cararo, Coraline; Contreras, Vanessa; Caruso, Agathe; Top, Sokunthea; Szelechowski, Marion; Bergeron, Corinne; Viarouge, Cyril; Desprat, Alexandra; Relmy, Anthony; Guibert, Jean-Michel; Dubois, Eric; Thiery, Richard; Bréard, Emmanuel; Bertagnoli, Stephane; Richardson, Jennifer; Foucras, Gilles; Meyer, Gilles; Schwartz-Cornil, Isabelle; Zientara, Stephan; Klonjkowski, Bernard

2014-01-01

331

Bluetongue virus (BTV) is an economically important Orbivirus transmitted by biting midges to domestic and wild ruminants. The need for new vaccines has been highlighted by the occurrence of repeated outbreaks caused by different BTV serotypes since 1998. The major group-reactive antigen of BTV, VP7, is conserved in the 26 serotypes described so far, and its role in the induction of protective immunity has been proposed. Viral-based vectors as antigen delivery systems display considerable promise as veterinary vaccine candidates. In this paper we have evaluated the capacity of the BTV-2 serotype VP7 core protein expressed by either a non-replicative canine adenovirus type 2 (Cav-VP7 R0) or a leporipoxvirus (SG33-VP7), to induce immune responses in sheep. Humoral responses were elicited against VP7 in almost all animals that received the recombinant vectors. Both Cav-VP7 R0 and SG33-VP7 stimulated an antigen-specific CD4+ response and Cav-VP7 R0 stimulated substantial proliferation of antigen-specific CD8+ lymphocytes. Encouraged by the results obtained with the Cav-VP7 R0 vaccine vector, immunized animals were challenged with either the homologous BTV-2 or the heterologous BTV-8 serotype and viral burden in plasma was followed by real-time RT-PCR. The immune responses triggered by Cav-VP7 R0 were insufficient to afford protective immunity against BTV infection, despite partial protection obtained against homologous challenge. This work underscores the need to further characterize the role of BTV proteins in cross-protective immunity. PMID:25364822

Bouet-Cararo, Coraline; Contreras, Vanessa; Caruso, Agathe; Top, Sokunthea; Szelechowski, Marion; Bergeron, Corinne; Viarouge, Cyril; Desprat, Alexandra; Relmy, Anthony; Guibert, Jean-Michel; Dubois, Eric; Thiery, Richard; Bréard, Emmanuel; Bertagnoli, Stephane; Richardson, Jennifer; Foucras, Gilles; Meyer, Gilles; Schwartz-Cornil, Isabelle; Zientara, Stephan; Klonjkowski, Bernard

2014-01-01

332

Directory of Open Access Journals (Sweden)

Full Text Available

**Background**: The outbreak of vector-associated diseases is determined by different factors. One of them is the existence of appropriate climatic conditions which influence the development of vectors as well as pathogens. Nowadays, accurate data on the occurrence of both vectors and pathogens are often not available in Germany, espite the coastal zones of Lower Saxony (Germany being former malaria regions. Thus, the question arises, whether a new autochthonous transmission could take place due to the monthly mean temperatures of recent ears taking into consideration the predicted increase in air temperatures according to the IPCC scenarios.

**Methods**: To model areas at risk, the transmission potential for new tertian malaria spreads in respect to emperature was computed in a GIS environment using the Basic Reproduction Rate (R0 formula.

**Results**:We were able to corroborate that the risk of tertian malaria transmission is increasing as temperature s the determining variable of the mathematical model.

**Conclusions**: Lower Saxony is at risk of a new outbreak of tertian malaria assuming no other risk factors than emperature being of relevance.

Gunther Schmidt

2008-12-01

333

The packaging determinants of feline immunodeficiency virus (FIV) consist of two discontinuous core regions, extending from R to approximately 150 bp of the 5' untranslated region and the first approximately 100 bp of gag. However, the role of sequences intervening between the core regions in packaging has not been clear. A mutational analysis was conducted to determine whether the intervening sequences played a role in FIV RNA packaging, using an in vivo packaging assay complemented with semiquantitative reverse transcriptase PCR. Our analyses reveal that the intervening sequences are dispensable not only for vector RNA packaging but also for propagation, confirming the discontinuous nature of the FIV packaging signal. PMID:16227303

Mustafa, Farah; Ghazawi, Akela; Jayanth, Preethi; Phillip, Pretty Susan; Ali, Jahabar; Rizvi, Tahir A

2005-11-01

334

New Constitutive Vectors: Useful Genetic Engineering Tools for Biocatalysis

Constitutive vectors are useful tools for genetic engineering. Two constitutive vectors with high levels of expression and broad host ranges were developed and used in a range of Pseudomonas hosts. The vectors showed superior characteristics compared to the inducible vectors as well as the potential to be used as improved genetic tools for biocatalysis.

Xu, Youqiang; Tao, Fei; Ma, Cuiqing; Xu, Ping

2013-01-01

335

Chikungunya Virus–Vector Interactions

Directory of Open Access Journals (Sweden)

Full Text Available Chikungunya virus (CHIKV is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed.

Lark L. Coffey

2014-11-01

336

Chikungunya Virus–Vector Interactions

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes chikungunya fever, a severe, debilitating disease that often produces chronic arthralgia. Since 2004, CHIKV has emerged in Africa, Indian Ocean islands, Asia, Europe, and the Americas, causing millions of human infections. Central to understanding CHIKV emergence is knowledge of the natural ecology of transmission and vector infection dynamics. This review presents current understanding of CHIKV infection dynamics in mosquito vectors and its relationship to human disease emergence. The following topics are reviewed: CHIKV infection and vector life history traits including transmission cycles, genetic origins, distribution, emergence and spread, dispersal, vector competence, vector immunity and microbial interactions, and co-infection by CHIKV and other arboviruses. The genetics of vector susceptibility and host range changes, population heterogeneity and selection for the fittest viral genomes, dual host cycling and its impact on CHIKV adaptation, viral bottlenecks and intrahost diversity, and adaptive constraints on CHIKV evolution are also discussed. The potential for CHIKV re-emergence and expansion into new areas and prospects for prevention via vector control are also briefly reviewed. PMID:25421891

Coffey, Lark L.; Failloux, Anna-Bella; Weaver, Scott C.

2014-01-01

337

The Anopheles arabiensis genetic sexing strain ANO IPCL1 was developed based on a dieldrin resistant mutation. The strain has been shown to be practical and reliable in terms of female elimination by dieldrin treatments at larval stages, but has provided some difficulties when treatments were applied at the egg stage. The high natural sterility of this strain has advantages and disadvantages in both mass rearing and the sterilization process. In addition, its recombination rate, although relatively low, poses a threat of strain deterioration if left unchecked in a mass-rearing setting. The males of the ANO IPCL1 have been shown to be equally competitive as lab-reared males of the wild-type Dongola strain, but competitiveness decreased by half when irradiated with 75 Gy—a dose conferring >98% sterility. More controversial issues surround the use of dieldrin—a highly persistent organochlorine that is known to bioaccumulate in the food chain. The prospective use of large volumes of dieldrin in a mass-rearing facility and the retention of its residues by the male mosquitoes makes the use of the strain in the context of the sterile insect technique against this vector highly questionable, and therefore its implementation at a large scale cannot be recommended. PMID:25438257

Yamada, Hanano; Vreysen, Marc J B; Bourtzis, Kostas; Tschirk, Wolfgang; Chadee, Dave D; Gilles, Jeremie R L

2015-02-01

338

Larval management of the malaria vector, Anopheles gambiae Giles s.s., has been successful in reducing disease transmission. However, pesticides are not affordable to farmers in remote villages in Mali, and in other material resource poor countries. Insect resistance to insecticides and nontarget toxicity pose additional problems. Neem (Azadirachta indica A. Juss) is a tree with many beneficial, insect bioactive compounds, such as azadirachtin. We tested the hypothesis that neem leaf slurry is a sustainable, natural product, anopheline larvicide. A field study conducted in Sanambele (Mali) in 2010 demonstrated neem leaf slurry can work with only the available tools and resources in the village. Laboratory bioassays were conducted with third instar An. gambiae and village methods were used to prepare the leaf slurry. Experimental concentration ranges were 1,061-21,224 mg/L pulverized neem leaves in distilled water. The 50 and 90% lethal concentrations at 72 h were 8,825 mg/L and 15,212 mg/L, respectively. LC concentrations were higher than for other parts of the neem tree when compared with previous published studies because leaf slurry preparation was simplified by omitting removal of fibrous plant tissue. Using storytelling as a medium of knowledge transfer, villagers combined available resources to manage anopheline larvae. Preparation of neem leaf slurries is a sustainable approach which allows villagers to proactively reduce mosquito larval density within their community as part of an integrated management system. PMID:23270164

Luong, Kyphuong; Dunkel, Florence V; Coulibaly, Keriba; Beckage, Nancy E

2012-11-01

339

Energy Technology Data Exchange (ETDEWEB)

Purpose: The aim of this article is to investigate the energy dependence of the radiochromic film type, Gafchromic EBT-1, when scanned with a flatbed scanner for film readout. Methods: Dose response curves were determined for 12 different beam qualities ranging from a 10 kVp x-ray beam to a 15 MVp x-ray beam and include also two high energy electron beam qualities (6 and 18 MeV). The dose responses measured as net optical density (netOD) for the different beam qualities were normalized to the response of a reference beam quality (6 MVp). Results: A strong systematic energy dependence of the film response was found. The lower the effective beam energy, the less sensitive the EBT-1 films get. The maximum decrease in dose for the same film response between the 25 kVp and 6 MVp beam qualities was 44%. Additionally, a difference in energy dependence for different doses was discovered, meaning that higher doses show a smaller dependency on energy than lower doses. The maximum decrease in the normalized netOD was found to be 25% for a dose of 0.5 Gy relative to the normalized netOD for 10 Gy. Moreover, a scaling procedure is introduced, allowing the correction of the energy dependence for the investigated beam qualities and also for comparable x-ray beam qualities within the energy range studied. Conclusions: A strong energy dependence for EBT-1 radiochromic films was found. The films were readout with a flatbed scanner. If the effective beam energy is known, the energy dependence can be corrected with the introduced scaling procedure. Further investigation of the influence of the spectral band of the readout device on energy dependence is needed to understand the reason for the different energy dependences found in this and previous works.

Richter, Christian; Pawelke, Joerg; Karsch, Leonhard; Woithe, Julia [OncoRay--Radiation Research in Oncology, Technische Universitaet Dresden, Fetscherstrasse 74, 01307 Dresden (Germany) and Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden (Germany); OncoRay-Radiation Research in Oncology, Technische Universitaet Dresden, Fetscherstrasse 74, 01307 Dresden (Germany)

2009-12-15

340

International Nuclear Information System (INIS)

Purpose: The aim of this article is to investigate the energy dependence of the radiochromic film type, Gafchromic EBT-1, when scanned with a flatbed scanner for film readout. Methods: Dose response curves were determined for 12 different beam qualities ranging from a 10 kVp x-ray beam to a 15 MVp x-ray beam and include also two high energy electron beam qualities (6 and 18 MeV). The dose responses measured as net optical density (netOD) for the different beam qualities were normalized to the response of a reference beam quality (6 MVp). Results: A strong systematic energy dependence of the film response was found. The lower the effective beam energy, the less sensitive the EBT-1 films get. The maximum decrease in dose for the same film response between the 25 kVp and 6 MVp beam qualities was 44%. Additionally, a difference in energy dependence for different doses was discovered, meaning that higher doses show a smaller dependency on energy than lower doses. The maximum decrease in the normalized netOD was found to be 25% for a dose of 0.5 Gy relative to the normalized netOD for 10 Gy. Moreover, a scaling procedure is introduced, allowing the correction of the energy dependence for the investigated beam qualities and also for comparable x-ray beam qualities within the energy range studied. Conclusions: A strong energy dependence for EBT-1 radiochromic films was found. The films were readout with a flatbed scanner. If the effective beam energy is known, the energy depetive beam energy is known, the energy dependence can be corrected with the introduced scaling procedure. Further investigation of the influence of the spectral band of the readout device on energy dependence is needed to understand the reason for the different energy dependences found in this and previous works.

341

International Nuclear Information System (INIS)

The effect of Adriamycin (doxorubicin hydrochloride) (10 mg/kg intraperitoneally) on the response of mouse gut to irradiation with 6-MVp photons or fast neutrons (67 MeV p ? Be), was assessed with the six-day death endpoint. The drug reduced the LD/sub 50/6/ by the same factor (approx. 1.25) for both types of radiation. Thus, the radiobiological effectiveness (RBE) (photons/neutrons) for gut damage is unaltered by the addition of Adriamycin. The data indicate no significant effect of drug scheduling if given within 16 hours before or after irradiation

342

International Nuclear Information System (INIS)

The effect of Adriamycin on the response of mouse gut to irradiation with 6-MVp photons or fast neutrons (67 MeV p--Be), was assessed with the six-day death endpoint. The drug reduced the LD50/6 by the same factor for both types of radiation. Thus, the radiobiological effectiveness (RBE) (photons/neutrons) for gut damage is unaltered by the addition of Adriamycin. The data indicated no significant effect of drug scheduling if given within 16 hours before or after irradiation

343

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Mosquitoes that breed in temporary pools in remote areas that dry up seasonally are especially difficult to control through chemical or biological means. The annual killifish has been suggested as a means of eradicating the aquatic stages of mosquitoes in transient pools because they can maintain permanent populations in such habitats by undergoing suspended animation or diapause during the embryonic stages to survive periodic drought. However, very little is known about the predatory activity of annual killifish and their usefulness in mosquito control. Results The annual killifish, Nothobranchius guentheri, native to Tanzania, was used in this investigation. Food preference was tested under laboratory conditions by feeding juvenile killifish with 2nd instar mosquito larvae of Culex quinquefasciatus in the presence of alternative food sources, such as rotifers and chironomid larvae. Semi-field tests were conducted by introduction of hibernating killifish embryos and juvenile fish to artificial ponds in an outdoor open environment that allowed natural oviposition of Cx. quinquefasciatus. Food preference studies show that N. guentheri preferred to prey on mosquito larvae than either chironomid or rotifers. When hibernating killifish embryos were added to ponds simultaneously with the addition of freshwater, the embryos hatched and fed on mosquito larval population resulting in complete elimination of the immature stages. The introduction of juvenile fish to ponds with high density of mosquito larvae resulted in total eradication of the mosquito population due to predation by fish. Complete biocontrol of the mosquito larval population was achieved in the presence of 3 fish per m2 of pond surface area. Conclusions The annual killifish provides yet another tool that may be employed in the eradication diseases carried by mosquitoes through vector control, particularly in temporary bodies of freshwater. The fish can be conveniently transported in the absence of water in the form of hibernating embryos. Once introduced either as embryos or juveniles in ponds, the annual killifish can effectively reduce the larval population because of its aggressive predatory activity.

Adrias Araceli Q

2010-05-01

344

Vectorization, parallelization and porting of nuclear codes (porting). Progress report fiscal 1999

International Nuclear Information System (INIS)

Several computer codes in the nuclear field have been vectorized, parallelized and transported on the FUJITSU VPP500 system, the AP3000 system, the SX-4 system and the Paragon system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 18 codes in fiscal 1999. These results are reported in 3 parts, i.e., the vectorization and the parallelization part on vector processors, the parallelization port on scalar processors and the porting part. In this report, we describe the porting. In this porting part, the porting of Assisted Model Building with Energy Refinement code version 5 (AMBER5), general purpose Monte Carlo codes far neutron and photon transport calculations based on continuous energy and multigroup methods (MVP/GMVP), automatic editing system for MCNP library code (autonj), neutron damage calculations for materials irradiations and neutron damage calculations for compounds code (SPECTER/SPECOMP), severe accident analysis code (MELCOR) and COolant Boiling in Rod Arrays, Two-Fluid code (COBRA-TF) on the VPP500 system and/or the AP3000 system are described. (author)

345

Vectorization, parallelization and porting of nuclear codes (porting). Progress report fiscal 1999

Energy Technology Data Exchange (ETDEWEB)

Several computer codes in the nuclear field have been vectorized, parallelized and transported on the FUJITSU VPP500 system, the AP3000 system, the SX-4 system and the Paragon system at Center for Promotion of Computational Science and Engineering in Japan Atomic Energy Research Institute. We dealt with 18 codes in fiscal 1999. These results are reported in 3 parts, i.e., the vectorization and the parallelization part on vector processors, the parallelization port on scalar processors and the porting part. In this report, we describe the porting. In this porting part, the porting of Assisted Model Building with Energy Refinement code version 5 (AMBER5), general purpose Monte Carlo codes far neutron and photon transport calculations based on continuous energy and multigroup methods (MVP/GMVP), automatic editing system for MCNP library code (autonj), neutron damage calculations for materials irradiations and neutron damage calculations for compounds code (SPECTER/SPECOMP), severe accident analysis code (MELCOR) and COolant Boiling in Rod Arrays, Two-Fluid code (COBRA-TF) on the VPP500 system and/or the AP3000 system are described. (author)

Kawasaki, Nobuo; Nemoto, Toshiyuki; Kawai, Wataru; Ishizuki, Shigeru [Fujitsu Ltd., Tokyo (Japan); Ogasawara, Shinobu; Kume, Etsuo; Adachi, Masaaki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Yatake, Yo-ichi [Hitachi Ltd., Tokyo (Japan)

2001-01-01

346

Rotations with Rodrigues' Vector

The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears…

Pina, E.

2011-01-01

347

This online encyclopedia article discusses vector-borne diseases. It defines vectors as the transmitters of disease-causing organisms that carry the pathogens from one host to another. The article reviews the biological range of vectors, the transmission and types of vector-borne diseases, patterns of occurrence and existing control measures.

Harvey Artsob

348

Scientific Electronic Library Online (English)

Full Text Available En Colombia están registradas 143 especies de Lutzomyia França, pero menos del 7% de éstas se encuentran incriminadas como vectores de Leishmania spp. Debido a la alta semejanza morfológica de algunas especies vectoras con otras no vectoras, se necesitan caracteres taxonómicos alternativos para iden [...] tificar correctamente los flebotomíneos de cada zona geográfica del país. Con este objetivo, en el presente trabajo se secuenció el extremo 3' del gen mitocondrial que codifica para la proteína citocromo b en tres vectores potenciales de Leishmania presentes en el valle de Aburrá, Colombia, Lutzomyia hartmanni (Fairchild y Hertig), L. columbiana (Ristorcelli y Van Ty) y L. tihuiliensis Le Pont, Torrez-Espejo y Dujardin. A partir del alineamiento múltiple de nucleótidos se determinaron los sitios polimórficos, las distancias genéticas pareadas netas (p) y la entropía. Las secuencias de nucleótidos fueron trasladadas a aminoácidos para estimar el número de sustituciones sinónimas y no sinónimas. En el alineamiento múltiple de 321 nucleótidos del gen citocromo b de L. columbiana, L. hartmanni y L. tihuiliensis se detectaron 83 sustituciones. En la secuencia parcial de la proteína se encontraron 18 reemplazos de aminoácidos. Las distancias genéticas interespecíficas fluctuaron en un rango mínimo de 0,137 entre L. tihuiliensis y L. columbiana, y un máximo de 0,215 entre L. columbiana y L. hartmanni. Los polimorfismos detectados en la secuencia de nucleótidos del gen y de aminoácidos de la proteína constituyen caracteres moleculares potencialmente útiles para la determinación taxonómica de estas especies de flebotomíneos. Abstract in english To date, 143 species of Lutzomyia França are recorded in Colombia, but less than 7% is incriminated in the transmission of Leishmania spp. Alternative taxonomic characters are necessary to correctly identify the particular sand fly fauna in each Colombian region, and the separation of morphologicall [...] y similar vector and non-vector species. In order to detect useful molecular characters for the taxonomic determination of three potential vectors of Leishmania present in the Valle de Aburrá, Colombia, the present work sequenced the 3' end of the mitochondrial cytochrome b gene in Lutzomyia hartmanni (Fairchild and Hertig), L. columbiana (Ristorcelli and Van Ty), and L. tihuiliensis Le Pont, Torrez-Espejo and Dujardin. Polymorphic sites, pairwise genetic distances (p), and entropy were determined from the multiple alignment of the nucleotide sequences. Numbers of silent and non silent substitutions were calculated from the amino acid sequences deduced from the nucleotide sequences of the gene. In the multiple alignment of the cytochrome b nucleotide sequences from Lutzomyia hartmanni, L. columbiana and L. tihuiliensis, 83 polymorphic sites were detected. A total of 18 amino acid replacements were found in the partial nucleotide sequences of the protein. Genetic distances varied from 0,137 between L. tihuiliensis and L. columbiana, to 0,215 among L. columbiana and L. hartmanni. Nucleotide and amino acid sequence polymorphisms within the cytochrome b gene and protein, respectively, constitute molecular characters potentially useful for the taxonomic determination of these sand fly species.

Alveiro, Pérez-Doria; Eduar, Elías Bejarano; Diana, Sierra; Iván Darío, Vélez.

2008-12-01

349

Cleome viscosa L. (Family: Capparaceae) commonly known as Tickweed or wild mustard and Tribulus terrestris L. (Family: Zygophyllaceae) commonly known as Gokhru, growing wildly in the desert areas in the monsoon and post monsoon season, are of great medicinal importance. Comparative larvicidal efficacy of the extracts from seeds of C. viscosa and fruits and leaves of T. terrestris was evaluated against 3rd or early 4th stage larvae of Anopheles stephensi (Liston), Aedes aegypti (Linnaeus) and Culex quinquefasciatus (Say) in different organic solvents. 24 and 48 hr LC50 and LC90 values along with their 95% fiducial limits, regression equation, chi-square (chi2)/ heterogeneity of the response was determined by log probit regression analysis. The 24 hr LC50 values as determined for seeds of C. viscosa were 144.1, 99.5 and 127.1 (methanol); 106.3, 138.9 and 118.5 (acetone) and 166.4, 162.5 and 301.9 mg l(-1) (petroleum ether extracts) for all the three mosquito species respectively showing that methanol and acetone extracts were a little bit more effective than the petroleum ether extracts. Experiments were carried out with fruits and leaves of T. terrestris with all the solvents and mosquito species. The 24 hr LC50 values, as determined for fruits of T. terrestris were 70.8, 103.4 and 268.2 (methanol); 74.0,120.5 and 132.0 (acetone) and 73.8,113.5 and 137.4 mg l(-1) (petroleum ether extracts) while the 24 hr LC50 values for leaves were 124.3, 196.8 and 246.5 (methanol); 163.4, 196.9 and 224.3 (acetone) and 135.8, 176.8 and 185.9 mg l(-1) (petroleum ether extracts) for all the three mosquito species respectively. The results clearly indicate that fruit extracts of T. terrestris were more effective as compared to leaves extracts in the three solvents tested. Larvae of An. stephensi were found more sensitive to both fruit and leaves extracts of T. terrestris followed by larvae of Ae. aegypti and Cx. quinquefasciatus. Extracts from the seeds of C. viscosa were found less effective as compared to the fruit extracts of T. terrestris indicating that active larvicidal principle may be present in the fruits of this plant species. The studywould be of great importance while formulating the control strategy, for vectors of malaria, dengue and lymphatic filariasis, based on alternative plant based insecticides in this semi-arid region. PMID:24665757

Bansal, S K; Singh, Karam V; Sharma, Sapna

2014-03-01

350

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Toxin complex (Tc family proteins were first identified as insecticidal toxins in Photorhabdus luminescens and have since been found in a wide range of bacteria. The genome of Yersinia pestis, the causative agent of bubonic plague, contains a locus that encodes the Tc protein homologues YitA, YitB, YitC, and YipA and YipB. Previous microarray data indicate that the Tc genes are highly upregulated by Y. pestis while in the flea vector; however, their role in the infection of fleas and pathogenesis in the mammalian host is unclear. Results We show that the Tc proteins YitA and YipA are highly produced by Y. pestis while in the flea but not during growth in brain heart infusion (BHI broth at the same temperature. Over-production of the LysR-type regulator YitR from an exogenous plasmid increased YitA and YipA synthesis in broth culture. The increase in production of YitA and YipA correlated with the yitR copy number and was temperature-dependent. Although highly synthesized in fleas, deletion of the Tc proteins did not alter survival of Y. pestis in the flea or prevent blockage of the proventriculus. Furthermore, YipA was found to undergo post-translational processing and YipA and YitA are localized to the outer membrane of Y. pestis. YitA was also detected by immunofluorescence microscopy on the surface of Y. pestis. Both YitA and YipA are produced maximally at low temperature but persist for several hours after transfer to 37°C. Conclusions Y. pestis Tc proteins are highly expressed in the flea but are not essential for Y. pestis to stably infect or produce a transmissible infection in the flea. However, YitA and YipA localize to the outer membrane and YitA is exposed on the surface, indicating that at least YitA is present on the surface when Y. pestis is transmitted into the mammalian host from the flea.

Spinner Justin L

2012-12-01

351

Analysing power for 28Si(n vector, nsub(0,1))28Si and sensitivity of spin-orbit potential parameters

International Nuclear Information System (INIS)

The analysing power Asub(y)(theta) for elastic and inelastic (2+, E*=1.78 MeV) neutron scattering from Si was measured at 14.1 MeV. The data were analysed together with published differential cross sections using the coupled-channels formalism. The parameters of the optical potential, especially for the spin-orbit part, could be definitely determined from the accurate analysing power data. (author)

352

Diploscapter, a thermotolerant, free-living soil bacterial-feeding nematode commonly found in compost, sewage, and agricultural soil in the United States, was studied to determine its potential role as a vehicle of Salmonella enterica serotype Poona, enterohemorrhagic Escherichia coli O157:H7, and Listeria monocytogenes in contaminating preharvest fruits and vegetables. The ability of Diploscapter sp. strain LKC25 to survive on agar media, in cow manure, and in composted turkey manure and to ...

Gibbs, Daunte S.; Anderson, Gary L.; Beuchat, Larry R.; Carta, Lynn K.; Williams, Phillip L.

2005-01-01

353

Fractional Brownian Vector Fields

This work puts forward an extended definition of vector fractional Brownian motion (fBm) using a distribution theoretic formulation in the spirit of Gel?fand and Vilenkin's stochastic analysis. We introduce random vector fields that share the statistical invariances of standard vector fBm (self-similarity and rotation invariance) but which, in contrast, have dependent vector components in the general case. These random vector fields result from the transformation of white noise by a special...

Tafti, P. D.; Unser, M.

2010-01-01

354

Nonintegrating Foamy Virus Vectors?

Foamy viruses (FVs), or spumaviruses, are integrating retroviruses that have been developed as vectors. Here we generated nonintegrating foamy virus (NIFV) vectors by introducing point mutations into the highly conserved DD35E catalytic core motif of the foamy virus integrase sequence. NIFV vectors produced high-titer stocks, transduced dividing cells, and did not integrate. Cells infected with NIFV vectors contained episomal vector genomes that consisted of linear, 1-long-terminal-repeat (1-...

Deyle, David R.; Li, Yi; Olson, Erik M.; Russell, David W.

2010-01-01

355

Objective. The aim of the present study was to develop a fully-automated computational solution for computer-aided diagnosis in Parkinson syndrome based on [123I]FP-CIT single photon emission computed tomography (SPECT) images. Approach. A dataset of 654 [123I]FP-CIT SPECT brain images from the Parkinson’s Progression Markers Initiative were used. Of these, 445 images were of patients with Parkinson’s disease at an early stage and the remainder formed a control group. The images were pre-processed using automated template-based registration followed by the computation of the binding potential at a voxel level. Then, the binding potential images were used for classification, based on the voxel-as-feature approach and using the support vector machines paradigm. Main results. The obtained estimated classification accuracy was 97.86%, the sensitivity was 97.75% and the specificity 98.09%. Significance. The achieved classification accuracy was very high and, in fact, higher than accuracies found in previous studies reported in the literature. In addition, results were obtained on a large dataset of early Parkinson’s disease subjects. In summation, the information provided by the developed computational solution potentially supports clinical decision-making in nuclear medicine, using important additional information beyond the commonly used uptake ratios and respective statistical comparisons. (ClinicalTrials.gov Identifier: NCT01141023)

Oliveira, Francisco P. M.; Castelo-Branco, Miguel

2015-04-01

356

International Nuclear Information System (INIS)

To obtain reactor physics parameters for high-moderation mixed-oxide (MOX) cores, Nuclear Power Engineering Corporation (NPEC), the French Atomic Commission (CEA), and their industrial partners have conducted a MOX core physics experimental program called MISTRAL (Refs. 1, 2, and 3) with the EOLE critical facility of the Cadarache research center. This program consists of four high-moderation cores and was successfully completed in July 2000. This paper describes the analysis results of MISTRAL-3 that is a homogeneous full MOX cylindrical core (H/HM = 6.2) with an 80-cm height and a 59-cm diameter consisting of 1388 standard pressurized water reactor-type MOX fuel rods of 7.0 wt% plutonium-enrichment in a square pitch of 1.39 cm. NPEC has been analyzing the experimental results by using the SRAC and MVP code systems (Refs. 4 and 5, respectively). SRAC performs pin cell calculations by the collision probability method and core calculations by the diffusion method (SRAC-CITATION) or the discrete ordinates transport method (SRAC-TWOTRAN). MVP is a continuous-energy Monte Carlo code. The JENDL-3.2 nuclear data file has been employed for these analyses. The measured and analyzed items of MISTRAL-3 are criticality, radial fission rate distribution, fission spectrum indices, conversion factors, isothermal temperature coefficients, differential and integral boron efficiency, two-dimensional (2-D) void worth, and absorber worth. Table I shows comparisons of calculated and measI shows comparisons of calculated and measured values of keff, radial fission rate distribution, fission spectrum indices, and conversion factors for MISTRAL-3 compared with those of MISTRAL-2 (homogeneous full MOX core, H/HM = 5.2) (Ref. 3). Regarding the criticality, the calculated values agree well with the measured. The differences of the calculated-to-experimental (C-E) values between MISTRAL-2 and MISTRAL-3 are within 0.1% ?k for all code systems. Regarding the radial fission rate distribution, the differences between the calculated and measured values are the same level as the experimental uncertainty for both the diffusion and Monte Carlo calculations. The fission spectrum indices are obtained by Pij calculations in SRAC with the 107-energy-group structure for a 5x5 multicell. A cell simulating a detector is placed at the corner of the array and is surrounded by 7.0 wt% MOX fuel rods. As shown in Table I, the calculated values agree well with the measured, being almost within the experimental uncertainty. The Pij calculations are performed to obtain the conversion factors in infinite lattice geometry, and the calculated value also agrees well with the measured. There are no apparent differences between MISTRAL-2 and MISTRAL-3 for the criticality, the fission rate distribution, the spectrum indices, and the conversion factors. The isothermal temperature coefficients were evaluated with measurement data among seven temperature points from 10 to 80 deg. C. The calculated values are obtained from the net reactivity change due to the temperature change with SRAC-CITATION, and they agree with the measured within approximately twice the experimental uncertainty. The differential boron efficiency was measured with changing boron concentration within ±3 ppm around the critical concentration of ?210 ppm. The calculated value of SRAC-CITATION shows good agreement with the measured within ?1 pcm/ppm. The integral boron efficiency measurements were performed for the boron concentrations of ?230, 330, 430, 630, and 820 ppm. The C-E values of the integral boron efficiency, which are calculated with SRAC-CITATION, vary from 0.98 to 1.03. The agreement between the calculated and measured values is within the experimental uncertainties (?5%). As for the isothermal temperature coefficients, the differential and integral boron efficiencies, there are also no apparent differences in the trend between MISTRAL-2 and MISTRAL-3. For the 2-D void worth measurements, the 7 x 7 cells at the center of the core were installed with thick over-claddings or Ag blocks in th

357

International Nuclear Information System (INIS)

We discuss the different roles of the ?- and ?A1-vector mesons for skyrmion stabilization in massive Yang-Mills models using variational arguments and numerical results. Employing the equivalence of massive Yang-Mills models and hidden-gauge models in the non-anomalous sector, we investigate the consequences for possible dynamical realizations of the vector limit of vanishing vector meson masses and coupling in the B=1 sector of hidden-gauge theories. In hidden-gauge models with axial vector mesons (additional to the vector mesons) the KSFR relation is not modified in the vector limit. (orig.)

358

Concise Vector Analysis is a five-chapter introductory account of the methods and techniques of vector analysis. These methods are indispensable tools in mathematics, physics, and engineering. The book is based on lectures given by the author in the University of Ceylon.The first two chapters deal with vector algebra. These chapters particularly present the addition, representation, and resolution of vectors. The next two chapters examine the various aspects and specificities of vector calculus. The last chapter looks into some standard applications of vector algebra and calculus.This book wil

Eliezer, C J; Maxwell, E A; Sneddon, I N

1963-01-01

359

A variational theory for monotone vector fields

Monotone vector fields were introduced almost 40 years ago as nonlinear extensions of positive definite linear operators, but also as natural extensions of gradients of convex potentials. These vector fields are not always derived from potentials in the classical sense, and as such they are not always amenable to the standard methods of the calculus of variations. We describe here how the selfdual variational calculus developed recently by the author, provides a variational ...

Ghoussoub, Nassif

2008-01-01

360

The increasing use of photosensitized processes for disinfection of microbiologically polluted waters requires a precise definition of the factors controlling the degree of photosensitivity in target and non-target organisms. In this regard, tests with protozoa and invertebrates which have a natural habitat in such waters may be used as first screening methods for the assessment of possible hazards for the ecosystem. A new cationic porphyrin, namely meso-tri(N-methyl-pyridyl)mono(N-dodecyl-pyridyl)porphine (C12), is tested in this work on the protozoan Ciliophora Colpoda inflata and Tetrahymena thermophila and the Crustacea Branchiopoda Artemia franciscana and Daphnia magna. The protocol involved 1 h incubation with porphyrin doses in the 0.1-10.0 ?M range and subsequent irradiation with visible light at a fluence rate of 10 mW cm(-2). The results indicate that C12 porphyrin has a significant affinity for C. inflata and T. thermophila; this is also shown by fluorescence microscopic analyses. C. inflata cysts were resistant to the phototreatment up to a porphyrin dose of 0.6 ?M. The effects of C12 on cysts have been evaluated at 3 and 24 h after the end of the phototreatment; a delay in the excystment process was observed. T. thermophila was fairly resistant to the phototreatment with C12 porphyrin. The data obtained with the two crustaceans indicated that the effects of dark- and photo-treatment with C12 need to be closely examined for every organism. A. franciscana is more resistant, probably owing to its ability to adapt to extreme conditions, while the high level of photosensitivity displayed by Daphnia magna represents a potential drawback, as this organism is often selected as a reference standard for assessing the environmental safety. Thus, while C12 photosensitisation can represent a useful tool for inducing a microbicidal or larvicidal action on polluted waters, the irradiation protocols must be carefully tailored to the nature of the specific water basin, and in particular to its biotic characteristics. PMID:22011789

Fabris, Clara; Soncin, Marina; Jori, Giulio; Habluetzel, Annette; Lucantoni, Leonardo; Sawadogo, Simon; Guidolin, Laura; Coppellotti, Olimpia

2012-02-01

361

Houseflies, Musca domestica (L.), are ubiquitous pests that have the potential to spread a variety of pathogens to humans, poultries, and dairies. Pesticides are commonly used for the management of this pest. Fipronil is a GABA-gated chloride channel-inhibiting insecticide that has been commonly used for the management of different pests including M. domestica throughout the world. Many pests have developed resistance to this insecticide. A field-collected strain of M. domestica was selected with fipronil for continuous 11 generations to assess the cross-resistance, genetics, and realized heritability for designing a resistance management strategy. Laboratory bioassays were performed using the feeding method of mixing insecticide concentrations with 20% sugar solutions and cotton soaks dipped in insecticide solutions were provided to tested adult flies. Bioassay results at G12 showed that the fipronil-selected strain developed a resistance ratio of 140-fold compared to the susceptible strain. Synergism bioassay with piperonyl butoxide (PBO) and S,S,S,-tributyl phosphorotrithioate (DEF) indicated that fipronil resistance was associated with microsomal oxidase and also esterase. Reciprocal crosses between resistant and susceptible strains showed an autosomal and incompletely dominant resistance to fipronil. The LC50 values of F1 and F'1 strains were not significantly different and dominance values were 0.74 and 0.64, respectively. The resistance to fipronil was completely recessive (D(ML) = 0.00) at the highest dose and incompletely dominant at the lowest dose (D(ML) = 0.87). The monogenic resistance based on chi-square goodness of fit test and calculation of the minimum number of segregating genes showed that resistance to fipronil is controlled by multiple genes. The fipronil resistance strain confirmed very low cross-resistance to emamectin benzoate and spinosad while no cross-resistance to chlorpyrifos and acetamiprid when compared to that of the field population. The heritability values were 0.112, 0.075, 0.084, 0.008, and 0.052 for fipronil, emamectin benzoate, spinosad, acetamiprid, and chlorpyrifos, respectively. It was concluded that fipronil resistance in M. domestica was autosomally inherited, incompletely dominant, and polygenic. These findings would be helpful for the better and successful management of M. domestica. PMID:24481906

Abbas, Naeem; Khan, Hafiz Azhar Ali; Shad, Sarfraz Ali

2014-04-01

362

Deterministic Vector Freak Waves

We construct and discuss a semi-rational, multi-parametric vector solution of coupled nonlinear Schr\\"odinger equations (Manakov system). This family of solutions includes known vector Peregrine solutions, bright-dark-rogue solutions, and novel vector unusual freak waves. The vector freak (or rogue) waves could be of great interest in a variety of complex systems, from optics to Bose-Einstein condensates and finance.

Baronio, Fabio; Conforti, Matteo; Wabnitz, Stefan

2012-01-01

363

Pulsed Vector Magnetic Potential Field Existence

Experimental confirmation discussed the effect of the immediate surroundings of a pulse-powered toroidal coil on biological material which was placed in an environment without the influence of electromagnetic force.

Ivan Rampl; Lukáš Palko; Pavel Hyršl; Libor Vojtek

2012-01-01

364

Interframe vector wavelet coding technique

Wavelet coding is often used to divide an image into multi- resolution wavelet coefficients which are quantized and coded. By 'vectorizing' scalar wavelet coding and combining this with vector quantization (VQ), vector wavelet coding (VWC) can be implemented. Using a finite number of states, finite-state vector quantization (FSVQ) takes advantage of the similarity between frames by incorporating memory into the video coding system. Lattice VQ eliminates the potential mismatch that could occur using pre-trained VQ codebooks. It also eliminates the need for codebook storage in the VQ process, thereby creating a more robust coding system. Therefore, by using the VWC coding method in conjunction with the FSVQ system and lattice VQ, the formulation of a high quality very low bit rate coding systems is proposed. A coding system using a simple FSVQ system where the current state is determined by the previous channel symbol only is developed. To achieve a higher degree of compression, a tree-like FSVQ system is implemented. The groupings are done in this tree-like structure from the lower subbands to the higher subbands in order to exploit the nature of subband analysis in terms of the parent-child relationship. Class A and Class B video sequences from the MPEG-IV testing evaluations are used in the evaluation of this coding method.

Wus, John P.; Li, Weiping

1997-01-01

365

Massive vector trapping as a gauge boson on a brane

We propose a mechanism to trap massive vector fields as a photon on the Randall-Sundrum brane embedded in the five dimensional AdS space. This localization-mechanism of the photon is realized by considering a brane action, to which a quadratic potential of the bulk-vector fields is added. We also point out that this potential gives very severe constraints on the fluctuations of the vector fields in the bulk space.

Ghoroku, K; Ghoroku, Kazuo; Nakamura, Akihiro

2002-01-01

366

Solitons, as stable localized wave packets that can propagate long distance in dispersive media without changing their shapes, are ubiquitous in nonlinear physical systems. Since the first experimental realization of optical bright solitons in the anomalous dispersion single mode fibers (SMF) by Mollenauer et al. in 1980 and optical dark solitons in the normal dispersion SMFs by P. Emplit et al. in 1987, optical solitons in SMFs had been extensively investigated. In reality a SMF always supports two orthogonal polarization modes. Taking fiber birefringence into account, it was later theoretically predicted that various types of vector solitons, including the bright-bright vector solitons, dark-dark vector solitons and dark-bright vector solitons, could be formed in SMFs. However, except the bright-bright type of vector solitons, other types of vector solitons are so far lack of clear experimental evidence. Optical solitons have been observed not only in the SMFs but also in mode locked fiber lasers. It has be...

Zhang, Han

2011-01-01

367

Canine vector-borne diseases in Brazil

Abstract Canine vector-borne diseases (CVBDs) are highly prevalent in Brazil and represent a challenge to veterinarians and public health workers, since some diseases are of great zoonotic potential. Dogs are affected by many protozoa (e.g., Babesia vogeli, Leishmania infantum, and Trypanosoma cruzi), bacteria (e.g., Anaplasma platys and Ehrlichia canis), and helminths (e.g., Dirofilaria immitis and Dipylidium caninum) that are transmitted by a diverse range of arthropod vectors, including ti...

Dantas-Torres Filipe

2008-01-01

368

Directory of Open Access Journals (Sweden)

Full Text Available This paper addresses the symbolic representation of non-convex real polyhedra, i.e., sets of real vectors satisfying arbitrary Boolean combinations of linear constraints. We develop an original data structure for representing such sets, based on an implicit and concise encoding of a known structure, the Real Vector Automaton. The resulting formalism provides a canonical representation of polyhedra, is closed under Boolean operators, and admits an efficient decision procedure for testing the membership of a vector.

Jean-François Degbomont

2010-10-01

369

Vectors and their applications

Geared toward undergraduate students, this text illustrates the use of vectors as a mathematical tool in plane synthetic geometry, plane and spherical trigonometry, and analytic geometry of two- and three-dimensional space. Its rigorous development includes a complete treatment of the algebra of vectors in the first two chapters.Among the text's outstanding features are numbered definitions and theorems in the development of vector algebra, which appear in italics for easy reference. Most of the theorems include proofs, and coordinate position vectors receive an in-depth treatment. Key concept

Pettofrezzo, Anthony J

2012-01-01

370

Vector generator scan converter

High printing speeds for graphics data are achieved with a laser printer by transmitting compressed graphics data from a main processor over an I/O (input/output) channel to a vector generator scan converter which reconstructs a full graphics image for input to the laser printer through a raster data input port. The vector generator scan converter includes a microprocessor with associated microcode memory containing a microcode instruction set, a working memory for storing compressed data, vector generator hardward for drawing a full graphic image from vector parameters calculated by the microprocessor, image buffer memory for storing the reconstructed graphics image and an output scanner for reading the graphics image data and inputting the data to the printer. The vector generator scan converter eliminates the bottleneck created by the I/O channel for transmitting graphics data from the main processor to the laser printer, and increases printer speed up to thirty fold.

Moore, James M. (Livermore, CA); Leighton, James F. (Livermore, CA)

1990-01-01

371

A theory of an acoustic vector soliton of self-induced transparency is constructed. By using the perturbative reduction method the magnetic Bloch equations and the equation of motion for the displacement field for the small area pulse are reduced to a system of two coupled nonlinear Schrödinger equations. The shape of an acoustic vector soliton with the sum and difference of the frequencies is presented. Explicit analytical expressions for the parameters of an acoustic vector soliton are obtained as well as simulations of an acoustic vector soliton presented with realistic parameters which can be reached in experiments. It is shown that the vector soliton in the special case can be reduced to the breather solution, and these nonlinear waves have different profiles. PMID:23005248

Adamashvili, G T

2012-06-01

372

Construction and Evaluation of Novel Rhesus Monkey Adenovirus Vaccine Vectors

ABSTRACT Adenovirus vectors are widely used as vaccine candidates for a variety of pathogens, including HIV-1. To date, human and chimpanzee adenoviruses have been explored in detail as vaccine vectors. The phylogeny of human and chimpanzee adenoviruses is overlapping, and preexisting humoral and cellular immunity to both are exhibited in human populations worldwide. More distantly related adenoviruses may therefore offer advantages as vaccine vectors. Here we describe the primary isolation and vectorization of three novel adenoviruses from rhesus monkeys. The seroprevalence of these novel rhesus monkey adenovirus vectors was extremely low in sub-Saharan Africa human populations, and these vectors proved to have immunogenicity comparable to that of human and chimpanzee adenovirus vaccine vectors in mice. These rhesus monkey adenoviruses phylogenetically clustered with the poorly described adenovirus species G and robustly stimulated innate immune responses. These novel adenoviruses represent a new class of candidate vaccine vectors. IMPORTANCE Although there have been substantial efforts in the development of vaccine vectors from human and chimpanzee adenoviruses, far less is known about rhesus monkey adenoviruses. In this report, we describe the isolation and vectorization of three novel rhesus monkey adenoviruses. These vectors exhibit virologic and immunologic characteristics that make them attractive as potential candidate vaccine vectors for both HIV-1 and other pathogens. PMID:25410856

Abbink, Peter; Maxfield, Lori F.; Ng'ang'a, David; Borducchi, Erica N.; Iampietro, M. Justin; Bricault, Christine A.; Teigler, Jeffrey E.; Blackmore, Stephen; Parenteau, Lily; Wagh, Kshitij; Handley, Scott A.; Zhao, Guoyan; Virgin, Herbert W.; Korber, Bette

2014-01-01

373

On cosmic inflation in vector field theories

We investigate the longitudinal ghost issue in vector inflation. It turns out that, within the class of Lorentz-invariant vector field theories with three degres of freedom and without any extra (scalar) fields, the possibilities are essentially exhausted by the classical solution due to Larry Ford with an extremely flat potential which doesn't feel the fast roll of its argument. And, moreover, one needs to fulfill an extra condition on that potential in order to avoid severe gradient instability. At the same time, some Lorentz-violating modifications are worth to be explored.

Golovnev, Alexey

2011-01-01

374

On cosmic inflation in vector field theories

International Nuclear Information System (INIS)

We investigate the longitudinal ghost issue in Abelian vector inflation. It turns out that, within the class of Lorentz-invariant vector field theories with three degrees of freedom and without any extra (scalar) fields, the possibilities are essentially exhausted by the classical solution due to Larry Ford with an extremely flat potential which does not feel the fast roll of its argument. And, moreover, one needs to fulfill an extra condition on that potential in order to avoid severe gradient instability. At the same time, some Lorentz-violating modifications are worth exploring. (paper)

375

On cosmic inflation in vector field theories

We investigate the longitudinal ghost issue in Abelian vector inflation. It turns out that, within the class of Lorentz-invariant vector field theories with three degrees of freedom and without any extra (scalar) fields, the possibilities are essentially exhausted by the classical solution due to Larry Ford with an extremely flat potential which does not feel the fast roll of its argument. And, moreover, one needs to fulfill an extra condition on that potential in order to avoid severe gradient instability. At the same time, some Lorentz-violating modifications are worth exploring.

Golovnev, Alexey

2011-12-01

376

R. brethesi is a sylvatic species from the Amazon region; it has been incriminated as responsible for the transmission of Chagas disease in collectors of piaçaba in this region. The aim of present study was to investigate the efficiency of these insects as potential vectors of Trypanosoma cruzi. Aspects related with feeding and defecation patterns, life time, and mortality had been observed in each instar of R. brethesi. We use 5th instar nymphs to get adults virgins, after the moulting 3 gr...

Dayse da Silva Rocha; Carolina Magalhães dos Santos; Vanda Cunha; José Jurberg; Cleber Galvão

2004-01-01

377

International Nuclear Information System (INIS)

Space-times admitting a null Killing vector are studied, using the Newman-Penrose spin coefficient formalism. The properties of the eigenrays (principal null curves of the Killing bivector) are shown to be related to the twist of the null Killing vector. Among the electrovacs, the ones containing a null Maxwell field turn out to belong to the twistfree class. An electrovac solution is obtained for which the null Killing vector is twisting and has geodesic and shearfree eigenrays. This solution is parameterless and appears to be the field of a zero-mass, spinning and charged source. (author)

378

Let A be a finitely generated algebra over a field K of characteristic p >0. We introduce a subring of the ring of Witt vectors W(A). We call it the ring of overconvergent Witt vectors. We prove that on a scheme X of finite type over K the overconvergent Witt vectors are an \\'etale sheaf. In a forthcoming paper (Annales ENS) we define an overconvergent de Rham-Witt complex on a smooth scheme X over a perfect field K whose hypercohomology is the rigid cohomology of X in the s...

Davis, Christopher James; Langer, Andreas; Zink, Thomas

2010-01-01

379

Foamy and Lentiviral Vectors Transduce Canine Long-Term Repopulating Cells at Similar Efficiency

Foamy viral vectors and lentiviral vectors are attractive gene transfer vectors for hematopoietic stem cell gene therapy because they both efficiently transduce stem cells using rapid ex vivo transduction protocols designed to maintain engraftment potential. Here we directly compared the ability of foamy and lentiviral vectors to transduce long-term hematopoietic repopulating cells in the dog model, using a competitive repopulation assay with vectors that express enhanced yellow or green fluo...

Trobridge, Grant D.; Allen, James; Peterson, Laura; Ironside, Christina; Russell, David W.; Kiem, Hans-peter

2009-01-01

380

The Vector Decomposition Problem

This paper introduces a new computational problem on a two-dimensional vector space, called the vector decomposition problem (VDP), which is mainly defined for designing cryptosystems using pairings on elliptic curves. We first show a relation between the VDP and the computational Diffie-Hellman problem (CDH). Specifically, we present a sufficient condition for the VDP on a two-dimensional vector space to be at least as hard as the CDH on a one-dimensional subspace. We also present a sufficient condition for the VDP with a fixed basis to have a trapdoor. We then give an example of vector spaces which satisfy both sufficient conditions and on which the CDH is assumed to be hard in previous work. In this sense, the intractability of the VDP is a reasonable assumption as that of the CDH.

Yoshida, Maki; Mitsunari, Shigeo; Fujiwara, Toru

381

Comment: This is the first part (of two parts) of a survey on the Witt vectors. A preprint version of a chapter for the Handbook of Algebra. There are 148 pages. Comments, criticims, suggestions, etc. welcome

Hazewinkel, Michiel

2008-01-01

382

The practical implementation of gene therapy in the clinical setting mandates gene delivery vehicles, or vectors, capable of efficient gene delivery selectively to the target disease cells. The utility of adenoviral vectors for gene therapy is restricted by their dependence on the native adenoviral primary cellular receptor for cell entry. Therefore, a number of strategies have been developed to allow CAR-independent infection of specific cell types, including the use of bispecific conjugates and genetic modifications to the adenoviral capsid proteins, in particular the fibre protein. These targeted adenoviral vectors have demonstrated efficient gene transfer in vitro , correlating with a therapeutic benefit in preclinical animal models. Such vectors are predicted to possess enhanced efficacy in human clinical studies, although anatomical barriers to their use must be circumvented.

Douglas, Joanne T.

383

Dynamic vector hysteresis modeling

International Nuclear Information System (INIS)

The possibility of considering dynamic effects in three vector hysteresis models is investigated. The friction model of oriented Preisach operators which rotate due to the torque exerted by the external field, the coercive spheres model, the 3D analogue of the classical Preisach model, and a further collective model based on micromagnetic analogy are considered. Furthermore, the 'external' dynamic generalization of the static hysteresis models is introduced for the vector case

384

This activity is designed to enhance student comprehension of air and wind velocity, through the use of real time flight data. Students will read about relative velocity, complete a work sheet on vectors, and then gather and analyze real world data. All of the materials, including links to sites for data collection, are provided in this learning object. After completing the activity, students will be able to define relative velocity, add and subtract vectors, and determine aircraft speed using raw data.

Weaver, David

385

Variational Relevance Vector Machines

The Support Vector Machine (SVM) of Vapnik (1998) has become widely established as one of the leading approaches to pattern recognition and machine learning. It expresses predictions in terms of a linear combination of kernel functions centred on a subset of the training data, known as support vectors. Despite its widespread success, the SVM suffers from some important limitations, one of the most significant being that it makes point predictions rather than generating pre...

Bishop, Christopher M.; Tipping, Michael

2013-01-01

386

Robustifying Vector Median Filter

This paper describes two methods for impulse noise reduction in colour images that outperform the vector median filter from the noise reduction capability point of view. Both methods work by determining first the vector median in a given filtering window. Then, the use of complimentary information from componentwise analysis allows to build robust outputs from more reliable components. The correlation among the colour channels is taken into account in the processing and, as a r...

Valentín Gregori; Samuel Morillas

2011-01-01

387

We construct vector bundles $R^r_\\mu$ on a smooth projective curve $X$ having the property that for all sheaves $E$ of slope $\\mu$ and rank $r$ on $X$ we have an equivalence: $E$ is a semistable vector bundle $\\iff$ $Hom(R^r_\\mu,E)=0$. As a byproduct of our construction we obtain effective bounds on $r$ such that the linear system $|R \\cdot \\Theta|$ has base points on the moduli space $U_X(r,r(g-1))$.

Hein, Georg

2007-01-01

388

We analyze a massive vector field with a non-canonical kinetic term in the action, minimally coupled to gravity, where the mass and kinetic function of the vector field vary as functions of time during inflation. The vector field is introduced following the same idea of a scalar curvaton, which must not affect the inflationary dynamics since its energy density during inflation is negligible compared to the total energy density in the Universe. Using this hypothesis, the vector curvaton will be solely responsible for generating the primordial curvature perturbation \\zeta. We have found that the spectra of the vector field perturbations are scale-invariant in superhorizon scales due to the suitable choice of the time dependence of the kinetic function and the effective mass during inflation. The preferred direction, generated by the vector field, makes the spectrum of \\zeta depend on the wavevector, i.e. there exists statistical anisotropy in \\zeta. This is discussed principally in the case where the mass of th...

Navarro, Andres A

2013-01-01

389

Viral Paratransgenesis in the Malaria Vector Anopheles gambiae

Paratransgenesis, the genetic manipulation of insect symbiotic microorganisms, is being considered as a potential method to control vector-borne diseases such as malaria. The feasibility of paratransgenic malaria control has been hampered by the lack of candidate symbiotic microorganisms for the major vector Anopheles gambiae. In other systems, densonucleosis viruses (DNVs) are attractive agents for viral paratransgenesis because they infect important vector insects, can be genetically manipu...

Ren, Xiaoxia; Hoiczyk, Egbert; Rasgon, Jason L.

2008-01-01

390

VectorBase: A Data Resource for Invertebrate Vector Genomics

VectorBase (http://www.vectorbase.org) is an NIAID-funded Bioinformatic Resource Center focused on invertebrate vectors of human pathogens. VectorBase annotates and curates vector genomes providing a web accessible integrated resource for the research community. Currently, VectorBase contains genome information for three mosquito species: Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus, a body louse Pediculus humanus and a tick species Ixodes scapularis. Since our last report Vect...

Lawson, Daniel; Arensburger, Peter; Besansky, Nora J.; Bruggner, Robert V.; Butler, Ryan; Campbell, Kathryn S.; Christophides, George K.; Christley, Scott; Dialynas, Emmanuel; Hammond, Martin; Hill, Catherine A.; Konopinski, Nathan; Lobo, Neil F.; Maccallum, Robert M.; Madey, Greg

2009-01-01

391

International Nuclear Information System (INIS)

Analyses were performed to verify nuclear data of some rare-earth elements (Dy, Ho, Er and Tm) by using the continuous energy Monte-Carlo code: MVP, and to evaluate the validity of the cross section libraries (JENDL-4.0, JENDL-3.3, ENDF/B-VII.0 and JEFF-3.1) by comparing infinite dilution cross section in SRAC library 107 energy groups. The difference of energy-integrated capture rate among these libraries is about 0.1% for Dy and 0.2% for Er at both E3 and EE1 cores, and the influence on energy-integrated capture rate by the difference of the cross section libraries is small at these cores. Though there is a relatively large difference in the C/E value of Ho2O3 at EE1 core between ENDF/B-VII.0 and JEFF-3.1, the difference of energy-integrated capture rate between these libraries is about 0.8% at EE1 core. (author)

392

Feline Foamy Virus-Based Vectors: Advantages of an Authentic Animal Model

New-generation retroviral vectors have potential applications in vaccination and gene therapy. Foamy viruses are particularly interesting as vectors, because they are not associated to any disease. Vector research is mainly based on primate foamy viruses (PFV), but cats are an alternative animal model, due to their smaller size and the existence of a cognate feline foamy virus (FFV). The potential of replication-competent (RC) FFV vectors for vaccination and replication-deficient (RD) FFV-bas...

Martin Löchelt; Torsten Hechler; Anne Bleiholder; Timo Kehl; Ann-Mareen Räthe; Qiuying Bao; Dragana Slavkovic Lukic; Yang Liu; Janet Lei; Weibin Liu

2013-01-01

393

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Parasite-vector interactions are fundamental in the transmission of vector-borne diseases such as leishmaniasis. Leishmania development in the vector sand fly is confined to the digestive tract, where sand fly midgut molecules interact with the parasites. In this work we sequenced and analyzed two midgut-specific cDNA libraries from sugar fed and blood fed female Phlebotomus perniciosus and compared the transcript expression profiles. Results A total of 4111 high quality sequences were obtained from the two libraries and assembled into 370 contigs and 1085 singletons. Molecules with putative roles in blood meal digestion, peritrophic matrix formation, immunity and response to oxidative stress were identified, including proteins that were not previously reported in sand flies. These molecules were evaluated relative to other published sand fly transcripts. Comparative analysis of the two libraries revealed transcripts differentially expressed in response to blood feeding. Molecules up regulated by blood feeding include a putative peritrophin (PperPer1, two chymotrypsin-like proteins (PperChym1 and PperChym2, a putative trypsin (PperTryp3 and four putative microvillar proteins (PperMVP1, 2, 4 and 5. Additionally, several transcripts were more abundant in the sugar fed midgut, such as two putative trypsins (PperTryp1 and PperTryp2, a chymotrypsin (PperChym3 and a microvillar protein (PperMVP3. We performed a detailed temporal expression profile analysis of the putative trypsin transcripts using qPCR and confirmed the expression of blood-induced and blood-repressed trypsins. Trypsin expression was measured in Leishmania infantum-infected and uninfected sand flies, which identified the L. infantum-induced down regulation of PperTryp3 at 24 hours post-blood meal. Conclusion This midgut tissue-specific transcriptome provides insight into the molecules expressed in the midgut of P. perniciosus, an important vector of visceral leishmaniasis in the Old World. Through the comparative analysis of the libraries we identified molecules differentially expressed during blood meal digestion. Additionally, this study provides a detailed comparison to transcripts of other sand flies. Moreover, our analysis of putative trypsins demonstrated that L. infantum infection can reduce the transcript abundance of trypsin PperTryp3 in the midgut of P. perniciosus.

Valenzuela Jesus G

2011-05-01

394

Modern video coding applications require transmission of video data over variable-bandwidth channels to a variety of terminals with different screen resolutions and available computational power. Scalable video coding is needed to optimally support these applications. Recently proposed wavelet-based video codecs employing spatial domain motion compensated temporal filtering (SDMCTF) provide quality, resolution and frame-rate scalability while delivering compression performance comparable to that of the state-of-the-art non-scalable H.264-codec. These codecs require scalable coding of the motion vectors in order to support a large range of bit-rates with optimal compression efficiency. Scalable motion vector coding algorithms based on the integer wavelet transform followed by embedded coding of the wavelet coefficients were recently proposed. In this paper, a new and fundamentally different scalable motion vector codec (MVC) using median-based motion vector prediction is proposed. Extensive experimental results demonstrate that the proposed MVC systematically outperforms the wavelet-based state-of-the-art solutions. To be able to take advantage of the proposed scalable MVC, a rate allocation mechanism capable of optimally dividing the available rate among texture and motion information is required. Two rate allocation strategies are proposed and compared. The proposed MVC and rate allocation schemes are incorporated into an SDMCTF-based video codec and the benefits of scalable motion vector coding are experimentally demonstrated.

Barbarien, Joeri; Munteanu, Adrian; Verdicchio, Fabio; Andreopoulos, Yiannis; Cornelis, Jan P.; Schelkens, Peter

2004-11-01

395

Biolarvicides, such as microbial formulations based on Bacillus thuringiensis and B. sphaericus, have been found to be highly effective against mosquito larvae and are currently employed as eco-friendly alternatives to synthetic chemical insecticides for vector control. Recently, a porphyrin of natural origin has been suggested as a sunlight-activatable larvicide against the dengue vector Aedes aegypti. In order to validate the approach for the control of the malaria vector, we tested the photo-larvicidal activity of a novel porphyrin, namely meso-tri(N-methyl-pyridyl), mono(N-dodecyl-pyridyl)porphine, C12, associated with two specifically selected carriers, against Anopheles gambiae s.s. and An. arabiensis larvae, both laboratory reared and collected from malaria endemic sites in Burkina Faso. Both C12-porphyrin formulates, when administered to larvae at a 50?M porphyrin dose, were accumulated in the alimentary canal. Subsequent exposure of the porphyrin-loaded larvae to sunlight for short times (0.5-3h) led to a complete mortality. The high efficacy exhibited by a "foodstuff" porphyrin formulate also in the presence of typical larval food particles opens promising perspectives for the development of an effective photocidal larvicide. PMID:22668835

Fabris, Clara; Ouédraogo, Robert Kossivi; Coppellotti, Olimpia; Dabiré, Roch K; Diabaté, Abdoulaye; Di Martino, Piera; Guidolin, Laura; Jori, Giulio; Lucantoni, Leonardo; Lupidi, Giulio; Martena, Valentina; Sawadogo, Simon P; Soncin, Marina; Habluetzel, Annette

2012-09-01

396

A rigorous introduction to calculus in vector spaces The concepts and theorems of advanced calculus combined with related computational methods are essential to understanding nearly all areas of quantitative science. Analysis in Vector Spaces presents the central results of this classic subject through rigorous arguments, discussions, and examples. The book aims to cultivate not only knowledge of the major theoretical results, but also the geometric intuition needed for both mathematical problem-solving and modeling in the formal sciences. The authors begin with an outline of key concepts, ter

Akcoglu, Mustafa A; Ha, Dzung Minh

2011-01-01

397

This outstanding text and reference applies matrix ideas to vector methods, using physical ideas to illustrate and motivate mathematical concepts but employing a mathematical continuity of development rather than a physical approach. The author, who taught at the U.S. Air Force Academy, dispenses with the artificial barrier between vectors and matrices--and more generally, between pure and applied mathematics.Motivated examples introduce each idea, with interpretations of physical, algebraic, and geometric contexts, in addition to generalizations to theorems that reflect the essential structur

Eisenman, Richard L

2013-01-01

398

Isotropy theorem for cosmological vector fields

We consider homogeneous abelian vector fields in an expanding universe. We find a mechanical analogy in which the system behaves as a particle moving in three dimensions under the action of a central potential. In the case of bounded and rapid evolution compared to the rate of expansion, we show by making use of the virial theorem that for arbitrary potential and polarization pattern, the average energy-momentum tensor is always diagonal and isotropic despite the intrinsic anisotropic evolution of the vector field. For simple power-law potentials of the form V=\\lambda (A^\\mu A_\\mu)^n, the average equation of state is found to be w=(n-1)/(n+1). This implies that vector coherent oscillations could act as natural dark matter or dark energy candidates. Finally, we show that under very general conditions, the average energy-momentum tensor of a rapidly evolving bounded vector field in any background geometry is always isotropic and has the perfect fluid form for any locally inertial observer.

Cembranos, J A R; Maroto, A L; Jareño, S J Núñez

2012-01-01

399

Centers for Disease Control (CDC) Podcasts

This podcast discusses emerging vector-borne pathogens, their role as prominent contributors to emerging infectious diseases, how they're spread, and the ineffectiveness of mosquito control methods. Created: 4/18/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID). Date Released: 4/27/2011.

2011-04-18

400

The development of a vector wind gust model through statistical analysis is described. Wind perturbation statistics which include location, altitude, season, and wavelength range are used in the synthesis of detailed wing profiles. These profiles provide the basis for the establishment of improved discrete gust design criteria guidelines for ascending launch vehicles.

Adelfang, S. I.

1984-01-01