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1

Verification of vectorized Monte Carlo code MVP using JRR-4 experiment of fast neutrons penetrating through graphite and water  

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

Theoretical and numerical difficulties in 3-D vector potential methods in finite element magnetostatic computations  

Science.gov (United States)

This paper describes the results of application of three well known 3D magnetic vector potential (MVP) based finite element formulations for computation of magnetostatic fields in electrical devices. The three methods were identically applied to three practical examples, the first of which contains only one medium (free space), while the second and third examples contained a mix of free space and iron. The first of these methods is based on the unconstrained curl-curl of the MVP, while the second and third methods are predicated upon constraining the divergence of the MVP 10 zero (Coulomb's Gauge). It was found that the two latter methods cease to give useful and meaningful results when the global solution region contains a mix of media of high and low permeabilities. Furthermore, it was found that their results do not achieve the intended zero constraint on the divergence of the MVP.

Demerdash, N. A.; Wang, R.

1990-01-01

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

Development of fast and accurate Monte Carlo code MVP  

Energy Technology Data Exchange (ETDEWEB)

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)

Mori, Takamasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2001-01-01

5

Core calculation of 1MWatt PUSPATI TRIGA reactor (RTP) using continuous energy method of 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. 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)

6

Vectorization, parallelization and implementation of nuclear codes [MVP/GMVP, QMDRELP, EQMD, HSABC, CURBAL, STREAM V3.1, TOSCA, EDDYCAL, RELAP5/MOD2/C36-05, RELAP5/MOD3] on the VPP500 computer system. Progress report 1995 fiscal year  

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)

7

Vectorization, parallelization and implementation of nuclear codes =MVP/GMVP, QMDRELP, EQMD, HSABC, CURBAL, STREAM V3.1, TOSCA, EDDYCAL, RELAP5/MOD2/C36-05, RELAP5/MOD3= on the VPP500 computer system. Progress report 1995 fiscal year  

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

Magnetic monopole, vector potential and gauge transformation  

International Nuclear Information System (INIS)

In connection with the charge quantization condition, the role of gauge transformation of the vector potential is investigated in Zumino's and Wu and Yang's formalisms. It is pointed out that two vector potentials related to each other by a gauge transformation are not necessarily equivalent to each other. (author)

9

MVP utilization for PWR design code  

Energy Technology Data Exchange (ETDEWEB)

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)

Matsumoto, Hideki; Tahara, Yoshihisa [Mitsubishi Heavy Industries Ltd., Tokyo (Japan)

2001-01-01

10

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)

11

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

Science.gov (United States)

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

12

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

13

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

14

Vector Potential, Electromagnetic Induction and "Physical Meaning"  

Science.gov (United States)

A forgotten experiment by Andre 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 [equation omitted] (when the induced circuit is at rest). The "good…

Giuliani, G.

2010-01-01

15

Electromagnetic potential vectors and the Lagrangian of a charged particle  

Science.gov (United States)

Maxwell's equations can be shown to imply the existence of two independent three-dimensional potential vectors. A comparison between the potential vectors and the electric and magnetic field vectors, using a spatial Fourier transformation, reveals six independent potential components but only four independent electromagnetic field components for each mode. Although the electromagnetic fields determined by Maxwell's equations give a complete description of all possible classical electromagnetic phenomena, potential vectors contains more information and allow for a description of such quantum mechanical phenomena as the Aharonov-Bohm effect. A new result is that a charged particle Lagrangian written in terms of potential vectors automatically contains a 'spontaneous symmetry breaking' potential.

Shebalin, John V.

1992-01-01

16

Scalar/Vector potential formulation for compressible viscous unsteady flows  

Science.gov (United States)

A scalar/vector potential formulation for unsteady viscous compressible flows is presented. The scalar/vector potential formulation is based on the classical Helmholtz decomposition of any vector field into the sum of an irrotational and a solenoidal field. The formulation is derived from fundamental principles of mechanics and thermodynamics. The governing equations for the scalar potential and vector potential are obtained, without restrictive assumptions on either the equation of state or the constitutive relations or the stress tensor and the heat flux vector.

Morino, L.

1985-01-01

17

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

18

On dynamics of velocity vector potential in incompressible fluids  

International Nuclear Information System (INIS)

An elegant quaternionic formulation is given for the Lagrangian advection equation for velocity vector potential in fluid dynamics. At first we study the topological significance of a restricted conserved quantity viz., stream-helicity and later more realistic configuration of open streamlines is figured out. Also, using Clebsch parameterisation of the velocity vector potential yet another physical significance for the stream-helicity is provided. Finally we give a Nambu-Poisson formalism of the Lagrangian advection equation for velocity vector potential.

19

Vector potential of the electromagnetic field of a photon  

International Nuclear Information System (INIS)

A solution of D'Alembert's equation for the vector potential of an electromagnetic field is found in the form of a wave packet, which does not spread in time and space. The expression obtained for the vector potential of a photon is used for the solution of some problems. (physical foundations of quantum electronics)

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

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)

22

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

23

Exploiting the potential of vector control for disease prevention.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Although vector control has proven highly effective in preventing disease transmission, it is not being used to its full potential, thereby depriving disadvantaged populations of the benefits of well tried and tested methods. Following the discovery of synthetic residual insecticides in the 1940s, large-scale programmes succeeded in bringing many of the important vector-borne diseases under control. By the late 1960s, most vector-borne diseases--with the exception of malaria in Africa--were n...

Townson, H.; Nathan, M. B.; Zaim, M.; Guillet, P.; Manga, L.; Bos, R.; Kindhauser, M.

2005-01-01

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

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)

26

Adenoviral Vectors in Veterinary Vaccine Development: Potential for Further Development  

Directory of Open Access Journals (Sweden)

Full Text Available  Vaccines are an integral part of veterinary disease prevention. However there are still a significant number of veterinary diseases for which vaccines do not currently exist or where currently available vaccines do not provide adequate immunity. Adenoviruses have transitioned from tools for gene replacement therapy to bona fide vaccine delivery vehicles because of their ability to elicit potent cell-mediated and humoral responses making them ideal for use against viruses and other intracellular pathogens. Adenoviral vector based vaccines are likely to play a significant role in overcoming these problems in the future. However, this vector is under utilized in veterinary vaccine development at this time. This review focuses on adenoviral vector based vaccines developed to date and explores the potential for veterinary vaccine development based upon this platform: advantages and potential disadvantages of this technology are discussed as well as the potential for developing efficacious commercial veterinary adenoviral vector based vaccines.

Olasumbo L. Ndi

2013-08-01

27

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

Science.gov (United States)

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

28

The Connection Between Inertial Forces and the Vector Potential  

CERN Document Server

. The inertia property of matter is discussed in terms of a type of induction law related to the extended charged particle's own vector potential. Our approach is based on the Lagrangian formalism of canonical momentum writing Newton's second law in terms of the vector potential and a development in terms of obtaining retarded potentials, that allow an intuitive physical interpretation of its main terms. This framework provides a clear physical insight on the physics of inertia. It is shown that the electron mass has a complete electromagnetic origin and the covariant equation obtained solves the "4/3 mass paradox". This provides a deeper insight into the significance of the main terms of the equation of motion. In particular a force term is obtained from the approach based on the continuity equation for momentum that represents a drag force the charged particle feels when in motion relatively to its own vector potential field lines. Thus, the time derivative of the particle's vector potential leads to the ac...

Martins, A A; Martins, Alexandre A.; Pinheiro, Mario J.

2006-01-01

29

Role of the nuclear vector potential in deep inelastic scattering  

International Nuclear Information System (INIS)

We study the influence of the strong nuclear vector potential, treated using the mean-field approximation, in deep inelastic scattering. A physically consistent treatment of the electromagnetic current operator, combined with the use of the operator product expansion is presented and discussed

30

A Vector Potential implementation for Smoothed Particle Magnetohydrodynamics  

CERN Document Server

The development of smooth particle magnetohydrodynamic (SPMHD) has significantly improved the simulation of complex astrophysical processes. However, the preservation the solenoidality of the magnetic field is still a severe problem for the MHD. A formulation of the induction equation with a vector potential would solve the problem. Unfortunately all previous attempts suffered from instabilities. In the present work, we evolve the vector potential in the Coulomb gauge and smooth the derived magnetic field for usage in the momentum equation. With this implementation we could reproduce classical test cases in a stable way. A simple test case demonstrates the possible failure of widely used direct integration of the magnetic field, even with the usage of a divergence cleaning method.

Stasyszyn, Federico

2014-01-01

31

Transient wave analysis program using wave equation of vector potential  

International Nuclear Information System (INIS)

To simulate time dependent electromagnetic field, a computer code named 'TWA-program' (Transient Wave Analysis program) was developed. The TWA-program solves the wave equation of the vector potential, and shows field lines on a computer graphic display. It was applied to solve problems such as the traveling microwave in a rectangular waveguide, the dipole radiation and beam induced field in a cavity structure. (orig.)

32

Equilibrium problems for infinite dimensional vector potentials with external fields  

CERN Document Server

The study deals with a minimal energy problem in the presence of an external field over noncompact classes of vector measures of infinite dimension in a locally compact space. The components are positive measures (charges) satisfying certain normalizing assumptions and supported by given closed sets (plates) with the sign +1 or -1 prescribed such that oppositely signed sets are mutually disjoint, and the interaction matrix for the charges corresponds to an electrostatic interpretation of a condenser. For all positive definite kernels satisfying Fuglede's condition of consistency between the weak* and strong topologies, sufficient conditions for the existence of equilibrium measures are established and properties of their uniqueness, vague compactness, and continuity are studied. We also obtain variational inequalities for the weighted equilibrium potentials, single out their characteristic properties, and analyze continuity of the equilibrium constants.

Zorii, Natalia

2009-01-01

33

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

Energy Technology Data Exchange (ETDEWEB)

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)

Okumura, Keisuke; Nakagawa, Masayuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kaneko, Kunio [Integrated Technical Information Research Organization, Tokyo (Japan); Sasaki, Makoto [Japan Research Institute, Ltd., Tokyo (Japan)

2001-01-01

34

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

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)

35

Large Lorentz Scalar and Vector Potentials in Nuclei  

CERN Document Server

In nonrelativistic models of nuclei, the underlying mass scales of low-energyquantum chromodynamics (QCD) are largely hidden. In contrast, the covariantformulations used in relativistic phenomenology manifest the QCD scales innuclei through large Lorentz scalar and four-vector nucleon self-energies. Theabundant and varied evidence in support of this connection and the consequencesare reviewed.

Furnstahl, R J; Serot, Brian D.

2000-01-01

36

Core calculation of 1MW PUSPATI TRIGA Reactor (RTP) using continuous energy method of Monte Carlo MVP code system  

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 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)

37

The periodic solutions of the Ginzburg-landau equation with periodic vector-potential  

International Nuclear Information System (INIS)

Ginzburg-Landau equation for one-variable order parameter modulus is considered in dimensionless form.Stability/instability regions of GL equation are considered.The periodic solutions of this equation are obtained in the case of periodic generalized vector-potential.In this problem generalized vector-potential consist of vector-potentials of the external electromagnetic field and field connecting with internal electronic structure of system.Existence of solutions comprising 1-kind Mathieu functions means that band theory of superconductivity may be constructed in fact

38

Potentiality of experimental analysis for characteristics of the Poynting vector components  

Directory of Open Access Journals (Sweden)

Full Text Available Potentiality of experimental analysis for the averaged Poynting vector components is considered. It is shown that joint application of traditional interferometry and Stocks polarimetry should allow for determining unambiguously characteristics of the Poynting vector components at each point of field.

Khrobatin R.

2008-09-01

39

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)

40

Silica nanoparticle: a potential new insecticide for mosquito vector control.  

Science.gov (United States)

Presently, there is a need for increased efforts to develop newer and effective methods to control mosquito vectors as the existing chemical and biological methods are not as effective as in earlier period owing to different technical and operational reasons. The use of nanomaterial products in various sectors of science including health increased during the last decade. We tested three types of nanosilica, namely lipophilic, hydrophilic and hydrophobic, to assess their larvicidal, pupicidal and growth inhibitor properties and also their influence on oviposition behaviour (attraction/deterrence) of mosquito species that transmit human diseases, namely malaria (Anopheles), yellow fever, chickungunya and dengue (Aedes), lymphatic filariasis and encephalitis (Culex and Aedes). Application of hydrophobic nanosilica at 112.5 ppm was found effective against mosquito species tested. The larvicidal effect of hydrophobic nanosilica on mosquito species tested was in the order of Anopheles stephensi > Aedes aegypti > Culex quinquefasciatus, and the pupicidal effect was in the order of A. stephensi > C. quinquefasciatus > Ae. aegypti. Results of combined treatment of hydrophobic nanosilica with temephos in larvicidal test indicated independent toxic action without any additive effect. This is probably the first report that demonstrated that nanoparticles particularly nanosilica could be used in mosquito vector control. PMID:22565400

Barik, Tapan K; Kamaraju, Raghavendra; Gowswami, Arunava

2012-09-01

 
 
 
 
41

Solutions of the Duffin-Kemmer-Petiau Equation Under a Vector Hellman Potential  

Science.gov (United States)

We present the approximate analytical solutions of Duffin-Kemmer-Petiau equation with a vector Hellmann potential for spin-zero particles. The energy eigenvalues and the corresponding eigenfunctions are obtained in closed form and some numerical results are included.

Ikot, Akpan N.; Hassanabadi, Hassan; Zarrinkamar, Saber; Yazarloo, Bentol Hoda

2014-03-01

42

Josephson Effect in Graphene: Comparison of Real and Pseudo Vector Potential Barriers  

Science.gov (United States)

The Josephson currents through real vector potential (RVP) and pseudo vector potential (PVP) barriers in graphene are investigated. In graphene, the pseudo vector potential may be caused by a local strain. The comparison of supercurrents induced by the two type-barriers is focused. As a result, we find that not only will the RVP induce a transition Josephson current from the 0 ? ? state but also causes the difference in the phases of the order parameters of the two superconducting graphene layers to shift from varphi ? varphi. The critical current is PVP-independent around the neutrality point while it strongly depends on the RVP. The vector potential dependence of critical current is found to be perfectly linear for both PVP and RVP barriers.

Tatnatchai, Suwannasit; Rassmidara, Hoonsawat; I-Ming, Tang; Bumned, Soodchomshom

2014-03-01

43

MVP/GMVP 2: general purpose Monte Carlo codes for neutron and photon transport calculations based on continuous energy and multigroup methods  

International Nuclear Information System (INIS)

In order to realize fast and accurate Monte Carlo simulation of neutron and photon transport problems, two vectorized Monte Carlo codes MVP and GMVP have been developed at JAERI. MVP is based on the continuous energy model and GMVP is on the multigroup model. Compared with conventional scalar codes, these codes achieve higher computation speed by a factor of 10 or more on vector super-computers. Both codes have sufficient functions for production use by adopting accurate physics model, geometry description capability and variance reduction techniques. The first version of the codes was released in 1994. They have been extensively improved and new functions have been implemented. The major improvements and new functions are (1) capability to treat the scattering model expressed with File 6 of the ENDF-6 format, (2) time-dependent tallies, (3) reaction rate calculation with the pointwise response function, (4) flexible source specification, (5) continuous-energy calculation at arbitrary temperatures, (6) estimation of real variances in eigenvalue problems, (7) point detector and surface crossing estimators, (8) statistical geometry model, (9) function of reactor noise analysis (simulation of the Feynman-? experiment), (10) arbitrary shaped lattice boundary, (11) periodic boundary condition, (12) parallelization with standard libraries (MPI, PVM), (13) supporting many platforms, etc. This report describes the physical model, geometry description method used in the codes, new functions and how to use them. (author)

44

Neutron cross section library production code system for continuous energy Monte Carlo code MVP. LICEM  

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)

45

Neutron cross section library production code system for continuous energy Monte Carlo code MVP. LICEM  

Energy Technology Data Exchange (ETDEWEB)

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).

Mori, Takamasa; Nakagawa, Masayuki [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Kaneko, Kunio

1996-05-01

46

Scattering of vector bosons by an asymmetric Hulthen potential  

Energy Technology Data Exchange (ETDEWEB)

Exact solutions for the bound and scattering states of the spatially one-dimensional Duffin-Kemmer-Petiau equation for an asymmetric Hulthen potential are obtained in terms of the hypergeometric functions. These solutions are used to derive conditions for the existence of the transmission resonances. From this investigation, we show how the transmission coefficient depends on the energy of the particle and the strength of the potential barrier.

Sogut, Kenan; Havare, Ali, E-mail: kenansogut@gmail.co, E-mail: ahavare@gmail.co [Mersin University, Department of Physics, Mersin 33143 (Turkey)

2010-06-04

47

Ecological Niche Modeling of Potential West Nile Virus Vector Mosquito Species in Iowa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ecological niche modeling (ENM) algorithms, Maximum Entropy Species Distribution Modeling (Maxent) and Genetic Algorithm for Rule-set Prediction (GARP), were used to develop models in Iowa for three species of mosquito — two significant, extant West Nile virus (WNV) vectors (Culex pipiens L and Culex tarsalis Coquillett (Diptera: Culicidae)), and the nuisance mosquito, Aedes vexans Meigen (Diptera: Culicidae), a potential WNV bridge vector. Occurrence data for the three mosquito species fro...

Larson, Scott R.; Degroote, John P.; Bartholomay, Lyric C.; Sugumaran, Ramanathan

2010-01-01

48

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

CERN Document Server

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 densi...

Inglis, S M

2012-01-01

49

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)

50

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

CERN Document Server

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

51

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

52

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

International Nuclear Information System (INIS)

We present an educational path for the magnetic vector potential A aimed at undergraduate students and pre-service physics teachers. Starting from the generalized Ampère–Laplace law, in the framework of a slowly varying time-dependent field approximation, the magnetic vector potential is written in terms of its empirical references, i.e. the conduction currents. Therefore, once the currents are known, our approach allows for 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 the calculation of A are analysed. (paper)

53

Exact Solutions of Klein–Gordon Equation with Scalar and Vector Rosen–Morse-Type Potentials  

International Nuclear Information System (INIS)

We obtain an exact analytical solution of the Klein–Gordon equation for the equal vector and scalar Rosen– Morse and Eckart potentials as well as the parity-time (PT) symmetric version of the these potentials by using the asymptotic iteration method. Although these PT symmetric potentials are non-Hermitian, the corresponding eigenvalues are real as a result of the PT symmetry. (general)

54

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 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)

55

Dirac equation for the harmonic scalar and vector potentials and linear plus coulomb-like tensor potential; the SUSY approach  

International Nuclear Information System (INIS)

The problem of analytical solutions of the 3-dimensional Dirac equation is usually studied via techniques such as The Nikiforov-Uvarov (NU) method. Here, we see that one of the most attractive potentials can be brought into a well-known form of Schroedinger-like problem possessing known solutions via the methodology of supersymmetry (SUSY). Next, using the idea of shape invariance, we calculate exact solutions of Dirac equation for quadratic scalar and vector potentials in the presence of a tensor potential that depends on the radial component either linearly or inversely. The tensor potential itself, besides its applications, removes degeneracy, too.

56

On the scattering of massive spinless bosons by a nonminimal vector smooth step potential  

International Nuclear Information System (INIS)

The Duffin-Kemmer-Petiau (DKP) equation for massive spinless bosons in the presence of a nonminimal vector smooth step potential is revised. The problem is mapped into a Sturm-Liouville equation. The reflection and transmission coefficients are obtained and discussed in detail. Furthermore, we show that Klein's paradox does not show its face in this sort of interaction.

57

Two-dimensional Dirac fermions with random axial-vector potential  

CERN Document Server

A Dirac fermion model with random axial-vector potential is proposed. At a special strength of randomness, the symmetry of the action is enhanced, which is due to the gauge symmetry \\`a la Nishimori. Some exact scaling exponents of single-particle Green functions are computed. The relationship with the XY gauge glass model is discussed.

Fukui, T; Yamada, H

2002-01-01

58

The inadmissibility of non-Stokesian vector potentials in quantum mechanics  

International Nuclear Information System (INIS)

The assertion made recently by Bocchieri and Loinger, that the Aharonov-Bohm effect is of purely mathematical origin, is refuted. It is shown that the use of non-Stokesian vector potentials is contrary to fundamental quantum mechanical principles. (author)

59

On T dependence of the static potential V(T; vector R) in a finite volume  

International Nuclear Information System (INIS)

We study the dependence on T of the static potential V(T; vector R) defined from Wilson loops and from Polyakov loop correlators on a finite lattice. For this study we employ a simple model with confinement, and compare with MC results. ((orig.))

60

On the scattering of massive spinless bosons by a nonminimal vector smooth step potential  

Energy Technology Data Exchange (ETDEWEB)

The Duffin-Kemmer-Petiau (DKP) equation for massive spinless bosons in the presence of a nonminimal vector smooth step potential is revised. The problem is mapped into a Sturm-Liouville equation. The reflection and transmission coefficients are obtained and discussed in detail. Furthermore, we show that Klein's paradox does not show its face in this sort of interaction.

Castro, L.B., E-mail: benito@feg.unesp.b [UNESP Campus de Guaratingueta, Departamento de Fisica e Quimica, 12516-410, Guaratingueta, SP (Brazil); Cardoso, T.R., E-mail: cardoso@feg.unesp.b [UNESP Campus de Guaratingueta, Departamento de Fisica e Quimica, 12516-410, Guaratingueta, SP (Brazil); Castro, A.S. de, E-mail: castro@pq.cnpq.b [UNESP Campus de Guaratingueta, Departamento de Fisica e Quimica, 12516-410, Guaratingueta, SP (Brazil)

2010-02-15

 
 
 
 
61

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

Science.gov (United States)

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.

Heras, José A.

2014-03-01

62

Scattering and bound states of spin-0 particles in a nonminimal vector double-step potential  

CERN Document Server

The problem of spin-0 particles subject to a nonminimal vector double-step potential is explored in the context of the Duffin-Kemmer-Petiau theory. Surprisingly, one can never have an incident wave totally reflected and the transmission amplitude has complex poles corresponding to bound states. The interesting special case of bosons embedded in a sign potential with its unique bound-state solution is analyzed as a limiting case.

de Oliveira, L P

2012-01-01

63

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

CERN Document Server

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.

Castilho, W M

2014-01-01

64

Development of transformation vectors for the production of potentially high oleate transgenic oil palm  

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

65

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.)

66

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

International Nuclear Information System (INIS)

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)

67

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Apolinario Rosa M; Clavo Bernardino; Lloret Marta; Lara Pedro C; Henríquez-Hernández Luis; Bordón Elisa; Fontes Fausto; Rey Agustín

2009-01-01

68

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

Science.gov (United States)

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

69

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)

70

Dynamic polarization potential effects on vector analyzing powers of 6Li-28Si elastic scattering from non-monotonic potentials  

International Nuclear Information System (INIS)

Experimental cross section (CS) and vector analyzing power (VAP) data of the 6Li-28Si elastic scattering at 22.8 MeV are analyzed in the coupled-channels (CC) and coupled discretized continuum channels (CDCC) methods. Non-monotonic (NM) 6Li and ? 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 iT11 data without the requirement of an additional static SO potential at the incident energy considered.

71

Ecology of Anopheles mosquitoes in Belgrade area: Estimating vector potential for malaria retransmission  

Directory of Open Access Journals (Sweden)

Full Text Available Belgrade is situated in the area that is potentially at risk from malaria outbrakes. Until eradication, the main vector of malaria in this area was Anopheles maculipennis s. s. (previous name An. typicus and secondary vectors were An. messeae and An. atroparvus. In this study we examined the distribution and ecology of Anopheles mosquitoes (Diptera, Culicidae in Belgrade. Females of Anopheles mosquitoes were collected from animal shelters in Belgrade at eight locations during 2003. Egg morphology was used to identify the specimens. A total of 3704 females deposited eggs ready for identification. Three species of An. maculipennis complex were identified: An. messeae, An. atroparvus and An. maculipennis s. s.. The most abundant species were An. messeae (64%. The relative frequency of three species varied depending on the site of collection. Seasonal fluctuations of mosquitoes' species varied. Each develops in a distinct type of water, too. The three species of the An. maculipennis complex, particularly An. messeae and An. atroparvus, are considered as potential vectors of malaria in Belgrade. With the possible reintroduction of Plasmodium species due to climatic changes and increased travel to and from the countries where malaria is endemic, a more efficient vector control is necessary.

Daki? Zorica

2008-01-01

72

Simulating the vector potential of gravitomagnetic monopole using spiral motions of confined spinning particles  

International Nuclear Information System (INIS)

Exact solutions to the time-dependent Schroedinger equation that governs the spiral motions of spinning particles are obtained, and the geometric phases that can be written as path integral of the vector potential of gravitomagnetic monopole (dual mass) are studied. Two illustrative examples of the confined spinning particles (e.g. a photon moving in a helical fiber and an electron confined by a planar radial electric field) are considered. It is shown that the confined spinning particles undergoing spiral motions seem to move inside a gravitomagnetic field produced by an equivalent gravitomagnetic monopole, i.e. the wavefunctions in the spiral motions of confined spinning particles acquire geometric phases, which are equivalent to the phase shift of a zero-spin particle that moves in the vector potential of a gravitomagnetic monopole. This means that the spiral motions of the confined spinning particles in proper potential fields can be used to simulate the gravitomagnetic vector potentials of dual mass. Though there is at present no evidence for the existence of gravitomagnetic monopole, the work presented here may stimulate interest in some areas such as the gravitationally induced quantum effects (relativistic quantum gravitational effects).

73

Simulating the vector potential of gravitomagnetic monopole using spiral motions of confined spinning particles  

Energy Technology Data Exchange (ETDEWEB)

Exact solutions to the time-dependent Schroedinger equation that governs the spiral motions of spinning particles are obtained, and the geometric phases that can be written as path integral of the vector potential of gravitomagnetic monopole (dual mass) are studied. Two illustrative examples of the confined spinning particles (e.g. a photon moving in a helical fiber and an electron confined by a planar radial electric field) are considered. It is shown that the confined spinning particles undergoing spiral motions seem to move inside a gravitomagnetic field produced by an equivalent gravitomagnetic monopole, i.e. the wavefunctions in the spiral motions of confined spinning particles acquire geometric phases, which are equivalent to the phase shift of a zero-spin particle that moves in the vector potential of a gravitomagnetic monopole. This means that the spiral motions of the confined spinning particles in proper potential fields can be used to simulate the gravitomagnetic vector potentials of dual mass. Though there is at present no evidence for the existence of gravitomagnetic monopole, the work presented here may stimulate interest in some areas such as the gravitationally induced quantum effects (relativistic quantum gravitational effects)

Qi Shen Jian [Centre for Optical and Electromagnetic Research, East Building No. 5, Zijingang Campus, Zhejiang University, Hangzhou 310058 (China); Cheng Yao [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)], E-mail: jqshen@coer.zju.edu.cn

2008-10-15

74

Vector Potential Electromagnetic Theory with Generalized Gauge for Inhomogeneous Anisotropic Media  

CERN Document Server

Vector and scalar potential formulation is valid from quantum theory to classical electromagnetics. The rapid development in quantum optics calls for electromagnetic solutions that straddle quantum physics as well as classical physics. The vector potential formulation is a good candidate to bridge these two regimes. Hence, there is a need to generalize this formulation to inhomogeneous media. A generalized gauge is suggested for solving electromagnetic problems in inhomogenous media which can be extended to the anistropic case. The advantages of the resulting equations are their absence of low-frequency catastrophe. Hence, usual di?erential equation solvers can be used to solve them over multi-scale and broad bandwidth. It is shown that the interface boundary conditions from the resulting equations reduce to those of classical Maxwell's equations. Also, classical Green's theorem can be extended to such a formulation, resulting in similar extinction theorem, and surface integral equation formulation for surfac...

Chew, Weng Cho

2014-01-01

75

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

CERN Document Server

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

76

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Inglis, S. M.; Jarvis, P. D.

2012-01-01

77

Transverse-longitudinal part of a vector potential in classical electrodynamics  

International Nuclear Information System (INIS)

Existence of a physical (gauge-invariant) degree of freedom of the vector potential generating no electromagnetic fields is proved in classical electrodynamics within the Dirac generalized Hamiltonian dynamics. The gauge-invariant form of electrodynamics of charged particles is given within which the question of observing the obtained degree of freedom is discussed. It is shown that it caused an electric current in a superconducting ring put on the solenoid. 20 refs

78

[Variation of vector potential in laboratory conditions changes biological properties of water].  

Science.gov (United States)

It was found that water preliminary activated with vector potential changes mobility of infusoria, bringing into it, the rate of sugar fermentation in yeast cells and a drinking attractivity of water for mice. It was also shown that water physical parameters changed after water activation: UV absorptions spectrum and a state of a silica admixture. It was supposed that water is the initial target when weak electromagnetic fields have an influence on biological objects. PMID:22873059

Anosov, A V; Trukhan, É M

2012-01-01

79

A consistency condition for the vector potential in multiply-connected domains  

CERN Document Server

A classical problem in electromagnetics concerns the representation of the electric and magnetic fields in the low-frequency or static regime, where topology plays a fundamental role. For multiply connected conductors, at zero frequency the standard boundary conditions on the tangential components of the magnetic field do not uniquely determine the vector potential. We describe a (gauge-invariant) consistency condition that overcomes this non-uniqueness and resolves a longstanding difficulty in inverting the magnetic field integral equation.

Epstein, Charles L; Greengard, Leslie; Klöckner, Andreas; O'Neil, Michael

2012-01-01

80

Rippled Graphene in an In-Plane Magnetic Field: Effects of a Random Vector Potential  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 quasi-random Lorentz forces lead to anisotropic magnetoresistance. Distinct signatures of these two effects enable an independent estimation of the ripple amplitude and correlation length.

Lundeberg, Mark B.; Folk, Joshua A.

2009-01-01

 
 
 
 
81

Calculation of the magnetic vector potential in the TJ-II; Calculo del Potencial Magnetico Vector en el TJ-II  

Energy Technology Data Exchange (ETDEWEB)

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.

Lopez Fraguas, A.; Lopez Bruna, D.; Romero, J. A.

2005-07-01

82

Gauge Transformation Properties of Vector and Tensor Potentials Revisited a Group Quantization Approach  

CERN Document Server

The standard rules of transformation for gauge connections, such as vector potentials and metric tensors, are reexamined according to a group-oriented approach to quantization. In this scheme, the gauge group coordinates acquire dynamics outside the null mass shell, and they transfer degrees of freedom to the gauge potentials, which then become massive. The quantization of massless and massive non-Abelian Yang-Mills, linear Gravity and Abelian two-form gauge field theories are fully developed from this new approach, where a cohomological origin of mass is pointed out.

Calixto, M

2000-01-01

83

Analysis of superconducting electromagnetic finite elements based on a magnetic vector potential variational principle  

Science.gov (United States)

Electromagnetic finite elements are extended based on a variational principle that uses the electromagnetic four potential as primary variable. The variational principle is extended to include the ability to predict a nonlinear current distribution within a conductor. The extension of this theory is first done on a normal conductor and tested on two different problems. In both problems, the geometry remains the same, but the material properties are different. The geometry is that of a 1-D infinite wire. The first problem is merely a linear control case used to validate the new theory. The second problem is made up of linear conductors with varying conductivities. Both problems perform well and predict current densities that are accurate to within a few ten thousandths of a percent of the exact values. The fourth potential is then removed, leaving only the magnetic vector potential, and the variational principle is further extended to predict magnetic potentials, magnetic fields, the number of charge carriers, and the current densities within a superconductor. The new element produces good results for the mean magnetic field, the vector potential, and the number of superconducting charge carriers despite a relatively high system condition number. The element did not perform well in predicting the current density. Numerical problems inherent to this formulation are explored and possible remedies to produce better current predicting finite elements are presented.

Schuler, James J.; Felippa, Carlos A.

1991-01-01

84

M-PEIs nanogels: potential nonviral vector for systemic plasmid delivery to tumor cells.  

Science.gov (United States)

Successfully systemic gene therapy has been hindered by vector-related limitations, including toxicity and inefficient gene delivery to tumor cells after intravenous administration. In this study, we evaluated the potential of spherical polyethylenimine nanogels (M-PEIs) as a novel vector for intravenous delivery of plasmids to tumor cells. M-PEIs provided a sustained release of plasmids up to 14 days and were also effective in protecting plasmids from enzymatic degradation in serum-conditioned media. M-PEIs showed no obvious cytotoxicity to mammalian cells in vitro as well as to liver, heart and kidney in mice after intravenous injection. Importantly, following intravenous administration of M-PEIs/plasmid complexes into human hepatocellular carcinoma xenograft-bearing mice, green fluorescence protein reporter gene expression was predominantly found in the tumor. This study indicates that M-PEIs may be a candidate for systemic delivery of plasmids into tumors. PMID:19180143

Dong, L; Xu, H; Liu, Y-B; Lu, B; Xu, D-M; Li, B-H; Gao, J; Wu, M; Yao, S-D; Zhao, J; Guo, Y-J

2009-07-01

85

Accurate computation of axisymmetric vector potential fields with the finite element method  

International Nuclear Information System (INIS)

A highly efficient formulation is described for implementing the finite element method for axisymmetric vector field analysis. The method was tested to investigate its full potential for the solution of steady-state and transient electromagnetic fields before application to specific problems. Computational tests show that the method requires comparable computing time to the equivalent Cartesian coordinate problem. The results of some numerical examples are presented including problems with different time-dependent source vectors. Results obtained are compared, where possible, against analytical solutions, as well as experimental results. An error analysis confirms that the accuracy is very good even for elements placed near the axis. Hence the singularity problem is effectively removed, as expected

86

Leptonic decays of vector mesons in a power-law potential model of independent quarks  

Science.gov (United States)

A relativistic power-law potential model of independent quarks is used to study the leptonic decays of neutral vector mesons. Here, the transition probability amplitude for leptonic decay of meson is determined from the momentum distribution function which is found from the assumption of a strong correlation existing between the momenta of quark and antiquark inside the meson. The model parameters are first determined from the application of the model to study the ground state spectra of ?, ?, ?, ? and ? mesons together with the radiative decay widths of mesons. The same model with no adjustable parameters is then used to evaluate the leptonic decay widths and the electromagnetic decay constants for the vector mesons ?, ?, ?, ? and ?. The calculated results are in remarkable agreement with the corresponding experimental values.

Jena, S. N.; Nanda, P. K.; Sahoo, S.; Panda, P.

2014-04-01

87

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%. 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

88

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

89

MVP Based Calculation of Reactivity Loss Due to Gemstone Irradiation Facility of Thai Research Reactor  

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

90

Chikungunya Viral Fitness Measures within the Vector and Subsequent Transmission Potential  

Science.gov (United States)

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

91

Stochastic and deterministic vector chromatography of suspended particles in one-dimensional periodic potentials.  

Science.gov (United States)

We present a comprehensive description of vector chromatography (VC) that includes deterministic and stochastic transport in one-dimensional periodic free-energy landscapes, with both energetic and entropic contributions, and identifies the parameters governing the deflection angle. 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 VC of colloidal particles based on both size and density. More generally, other fields, e.g., electric, dielectrophoretic, or magnetic, can play or enhance the role of gravity, potentially leading to a versatile technique. PMID:23003265

Bernate, Jorge A; Drazer, German

2012-05-25

92

Six-dimensional Davidson potential as a dynamical symmetry of the symplectic interacting vector boson model  

International Nuclear Information System (INIS)

A six-dimensional Davidson potential, introduced within the framework of the interacting vector boson model (IVBM), is used to describe nuclei that exhibit transitional spectra between the purely rotational and vibrational limits of the theory. The results are shown to relate to a new dynamical symmetry that starts with the Sp(12,R) superset of SU(1,1)xSO(6) reduction. Exact solutions for the eigenstates of the model Hamiltonian in the basis defined by a convenient subgroup chain of SO(6) are obtained. A comparison of the theoretical results with experimental data for heavy nuclei with transitional spectra illustrates the applicability of the theory

93

Vector bundles over configuration spaces of nonidentical particles: Topological potentials and internal degrees of freedom  

Energy Technology Data Exchange (ETDEWEB)

We consider configuration spaces of nonidentical pointlike particles. The physically motivated assumption that any two particles cannot be located at the same point in space{endash}time leads to nontrivial topological structure of the configuration space. For a quantum mechanical description of such a system, we classify complex vector bundles over the configuration space and obtain potentials of topological origin, similar to those that occur in the fiber bundle approach to Dirac{close_quote}s magnetic monopole or in Yang{endash}Mills theory. {copyright} {ital 1997 American Institute of Physics.}

Doebner, H.; Mann, H. [Arnold Sommerfeld Institute for Mathematical Physics, Technical University of Clausthal, 38678 Clausthal-Zellerfeld (Germany)

1997-08-01

94

Categorization of potential breeding sites of dengue vectors in Johor, Malaysia.  

Science.gov (United States)

This cross-sectional study was to compare and categorize potential breeding sites of dengue vectors, Aedes aegypti and Aedes albopictus at three different places, namely, an urban (Taman Permas Jaya, Johor Bahru, Johor), a suburban (Kg. Melayu Gelang Patah, Johor Bahru, Johor) and a rural (Felda Simpang Waha, Kota Tinggi, Johor) habitats in Malaysia. Larval surveys were conducted once in every two months at each habitat over a period of 11 months from August 2000 until June 2001. There was a significant difference between the three study sites in terms of potential breeding sites inspected (psuburban (29.35)>urban habitat (16.97). Both breeding sites and potential breeding sites were the nominator and the total number of containers inspected as the denominator in the formula of PCI, thus the latter could be a potential indicator to initiate anti-dengue campaign at the community level to rid off potential Aedes breeding sites. The three most common potential breeding sites of Aedes species were similar for urban and suburban habitats (flower pots, pails and bowls respectively). However, flower pots, vases and tyres were the three most common potential breeding sites for the rural habitat. Another finding in this study was that various types of larval habitats were found indoors and outdoors for both species. PMID:20562811

Nyamah, M A; Sulaiman, S; Omar, B

2010-04-01

95

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)

96

Potential schistosome-vector snails and associated trematodes in ricefields of Corrients province, Argentina: preliminary results  

Directory of Open Access Journals (Sweden)

Full Text Available Considering the possibility of introduction of schistosomiasis mansoni into Argentina as a consequence of dam construction on the Rio De La Plata basin, preliminary studies have been carried out on agrosystems such as ricefields in Corrientes province with the following purposes: 1 to survey and estimate the relative abundance of planorbids and identify potential vector species; 2 to identify environmental factors capable of influencing Biomphalaria population dynamics; and 3 to find out snail-parasite associations and estimate snail infection rates in order to detect possible competitive interactions between larval stages of native trematodes that could be used in biological control of Schistosoma mansoni. Three potential schistosome vectors were detected in ricefields, namely Biomphalaria straminea, B. tenagophila and B. peregrina, although B. orbignyi, a species refractory to infection with S. mansoni, proved the most frequent and abundant. Positive correlations (P0.05 was found in total iron, phosphates (SRP, pH and soil granulometry. Echinocercariae developed from rediae and belonging to Petasiger sp., Paryphostomum sp., and other undetermined species were found.

Alejandra Rumi

1990-09-01

97

Potential schistosome-vector snails and associated trematodes in ricefields of Corrients province, Argentina: preliminary results  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Considering the possibility of introduction of schistosomiasis mansoni into Argentina as a consequence of dam construction on the Rio De La Plata basin, preliminary studies have been carried out on agrosystems such as ricefields in Corrientes province with the following purposes: 1) to survey and es [...] timate the relative abundance of planorbids and identify potential vector species; 2) to identify environmental factors capable of influencing Biomphalaria population dynamics; and 3) to find out snail-parasite associations and estimate snail infection rates in order to detect possible competitive interactions between larval stages of native trematodes that could be used in biological control of Schistosoma mansoni. Three potential schistosome vectors were detected in ricefields, namely Biomphalaria straminea, B. tenagophila and B. peregrina, although B. orbignyi, a species refractory to infection with S. mansoni, proved the most frequent and abundant. Positive correlations (P0.05) was found in total iron, phosphates (SRP), pH and soil granulometry. Echinocercariae developed from rediae and belonging to Petasiger sp., Paryphostomum sp., and other undetermined species were found.

Alejandra, Rumi; Monika Ines, Hamann.

98

Sampling methods for potential epidemic vectors of eastern equine encephalomyelitis virus in Massachusetts.  

Science.gov (United States)

To determine which of 11 trapping methods best sampled populations of 6 potential epidemic vectors of eastern equine encephalomyelitis (EEE) virus, we compared New Jersey (NJ) light trap, CDC light trap, CDC with octenol, CDC with CO2, CDC with CO2 plus octenol, American Biophysics light trap with flickering light (AB flicker), AB steady light, AB flicker with octenol, AB flicker with CO2, AB flicker with CO2 plus octenol, and 3 resting boxes. There was no significant difference between CDC and AB light traps (P > 0.05). The addition of octenol increased trap catch with both CDC and AB light traps; however, this increase was not statistically significant (P > 0.05). Both brands supplemented with CO2 collected more Aedes canadensis, Coquillettidia perturbans, Culex salinarius, and Anopheles spp. than did unbaited light traps (P octenol to CO2 increased collections of Anopheles spp. and decreased collections of Aedes spp. and Cq. perturbans at some sites, but these changes were not statistically significant (P > 0.05). Resting boxes were best for sampling bloodfed or parous Anopheles spp. The NJ, AB flicker, and AB steady light traps were not effective for sampling potential vectors of EEE virus. PMID:9474560

Vaidyanathan, R; Edman, J D

1997-12-01

99

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

CERN Document Server

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

MVP/GMVP II, MC Codes for Neutron and Photon Transport Calc. based on Continuous Energy and Multigroup Methods  

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

 
 
 
 
101

On the nonminimal vector coupling in the Duffin-Kemmer-Petiau theory and the confinement of massive bosons by a linear potential  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Vector couplings in the Duffin-Kemmer-Petiau theory are revised. It is shown that minimal and nonminimal vector potentials behave differently under charge-conjugation and time-reversal transformations. In particular, it is shown that nonminimal vector potentials have been erroneously applied to the description of elastic meson-nucleus scatterings and that the space component of the nonminimal vector potential plays a crucial role for the confinement of bosons. The DKP equati...

Cardoso, T. R.; Castro, L. B.; Castro, A. S.

2009-01-01

102

Bound states of the one-dimensional Dirac equation for scalar and vector double square-well potentials  

Science.gov (United States)

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

103

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)

104

Dynamics of vector solitons in two-component Bose–Einstein condensates with time-dependent interactions and harmonic potential  

International Nuclear Information System (INIS)

We present two kinds of exact vector-soliton solutions for coupled nonlinear Schroedinger equations with time-varying interactions and time-varying harmonic potential. Using the variational approach, we investigate the dynamics of the vector solitons. It is found that the two bright solitons oscillate about slightly and pass through each other around the equilibration state which means that they are stable under our model. At the same time, we obtain the opposite situation for dark-dark solitons. (general)

105

Larvicidal potential of silver nanoparticles synthesized from Leucas aspera leaf extracts against dengue vector Aedes aegypti.  

Science.gov (United States)

Vector-borne diseases caused by mosquitoes are one of the major economic and health problems in many countries. The Aedes aegypti mosquito is a vector of several diseases in humans like yellow fever and dengue. Vector control methods involving the use of chemical insecticides are becoming less effective due to development of insecticides resistance, biological magnification of toxic substances through the food chain, and adverse effects on environmental quality and non-target organisms including human health. Application of active toxic agents from plant extracts as an alternative mosquito control strategy was available from ancient times. These are nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. Today, nanotechnology is a promising research domain which has wide-ranging application vector control programs. The present study investigates the larvicidal potential of solvent leaf extracts of Leucas aspera and synthesized silver nanoparticles using aqueous leaf extract against fourth instar larvae of Aedes aegypti. Larvae were exposed to varying concentrations of plant extracts and synthesized AgNPs for 24 h. The results were recorded from UV-Vis spectra, x-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM), and were used to characterize and support the biosynthesis of silver nanoparticles. The formation of the AgNPs synthesized from the XRD spectrum compared with Bragg reflections can be indexed to the (111) orientations, respectively, confirmed the presence of AgNPs. The FT-IR spectra of AgNPs exhibited prominent peaks at 3,447.77; 2,923.30; and 1,618.66 cm(-1). The spectra showed sharp and strong absorption band at 1,618.66 cm(-1) assigned to the stretching vibration of (NH) C?O group. The band 1,383 developed for C?C and C?N stretching, respectively, and was commonly found in the proteins. SEM analysis of the synthesized AgNPs clearly showed the clustered and irregular shapes, mostly aggregated, and having the size of 25-80 nm. Energy-dispersive x-ray spectroscopy showed the complete chemical composition of the synthesized AgNPs. In larvicidal activity, the results showed that the maximum efficacy was observed in synthesized AgNPs leaf extracts against the fourth instar larvae of A. aegypti (LC50 values of 8.5632, 10.0361, 14.4689, 13.4579, 17.4108, and 27.4936 mg/l) and (LC90 values of 21.5685, 93.03928, 39.6485, 42.2029, 31.3009, and 53.2576 mg/l), respectively. These results suggest that the synthesized AgNPs leaf extracts have a higher larvicidal potential as compared to crude solvent extracts thus making them an effective combination for controlling A. aegypti. PMID:24553980

Suganya, Ganesan; Karthi, Sengodan; Shivakumar, Muthugounder S

2014-05-01

106

A Survey on Potential of the Support Vector Machines in Solving Classification and Regression Problems  

Directory of Open Access Journals (Sweden)

Full Text Available Kernel methods and support vector machines have become the most popular learning from examples paradigms. Several areas of application research make use of SVM approaches as for instance hand written character recognition, text categorization, face detection, pharmaceutical data analysis and drug design. Also, adapted SVM’s have been proposed for time series forecasting and in computational neuroscience as a tool for detection of symmetry when eye movement is connected with attention and visual perception. The aim of the paper is to investigate the potential of SVM’s in solving classification and regression tasks as well as to analyze the computational complexity corresponding to different methodologies aiming to solve a series of afferent arising sub-problems.

Luminita STATE

2010-01-01

107

The role of a form of vector potential normalization of the antisymmetric gauge  

CERN Document Server

Results obtained for the antisymmetric gauge A=[Hy,-Hx]/2 by Brown and Zak are compared with those based on pure group-theoretical considerations and corresponding to the Landau gauge A=[0,Hx]. Imposing the periodic boundary conditions one has to be very careful since the first gauge leads to a factor system which is not normalized. A period N introduced in Brown's and Zak's papers should be considered as a magnetic one, whereas the crystal period is in fact 2N. The `normalization' procedure proposed here shows the equivalence of Brown's, Zak's, and other approaches. It also indicates the importance of the concept of magnetic cells. Moreover, it is shown that factor systems (of projective representations and central extensions) are gauge-dependent, whereas a commutator of two magnetic translations is gauge-independent. This result indicates that a form of the vector potential (a gauge) is also important in physical investigations.

Florek, W; Florek, Wojciech; Walcerz, Stanislaw

1998-01-01

108

The endemic copepod Calanus pacificus californicus as a potential vector of white spot syndrome virus.  

Science.gov (United States)

The susceptibility of the endemic copepod Calanus pacificus californicus to white spot syndrome virus (WSSV) was established by the temporal analysis of WSSV VP28 transcripts by quantitative real-time PCR (qRT-PCR). The copepods were collected from a shrimp pond located in Bahia de Kino Sonora, Mexico, and challenged per os with WSSV by a virus-phytoplankton adhesion route. Samples were collected at 0, 24, 48 and 84 h postinoculation (hpi). The VP28 transcripts were not detected at early stages (0 and 24 hpi); however, some transcript accumulation was observed at 48 hpi and gradually increased until 84 hpi. Thus, these results clearly show that the copepod C. pacificus californicus is susceptible to WSSV infection and that it may be a potential vector for the dispersal of WSSV. However, further studies are still needed to correlate the epidemiological outbreaks of WSSV with the presence of copepods in shrimp ponds. PMID:24895865

Mendoza-Cano, Fernando; Sánchez-Paz, Arturo; Terán-Díaz, Berenice; Galván-Alvarez, Diego; Encinas-García, Trinidad; Enríquez-Espinoza, Tania; Hernández-López, Jorge

2014-06-01

109

Zero vector potential mechanism of attosecond absorption in strongly relativistic plasmas  

CERN Document Server

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

110

Control of tripod-scheme cold-atom wavepackets by manipulating a non-Abelian vector potential  

International Nuclear Information System (INIS)

Tripod-scheme cold atoms interacting with laser beams have attracted considerable interest for their role in synthesizing effective non-Abelian vector potentials. Such effective vector potentials can be exploited to realize an all-optical imprinting of geometric phases onto matter waves. By working on carefully designed extensions of our previous work, we show that coherent lattice structure of cold-atom sub-wavepackets can be formed and that the non-Abelian Aharonov-Bohm effect can be easily manifested via the translational motion of cold atoms. We also show that by changing the frame of reference, effects due to a non-Abelian vector potential may be connected with a simple dynamical phase effect, and that under certain conditions it can be understood as an Abelian geometric phase in a different frame of reference. Results should help design better schemes for the control of cold-atom matter waves.

111

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

Science.gov (United States)

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

112

A novel algebraic approach to spin symmetry for Dirac equation with scalar and vector second Poeschl-Teller potentials  

International Nuclear Information System (INIS)

By a novel algebraic method we study the approximate solution to the Dirac equation with scalar and vector second Poeschl-Teller potential carrying spin symmetry. The transcendental energy equation and spinor wave functions with arbitrary spin-orbit coupling quantum number k are presented. It is found that there exist only positive-energy bound states in the case of spin symmetry. Also, the energy eigenvalue approaches a constant when the potential parameter ? goes to zero. The equally scalar and vector case is studied briefly. (orig.)

113

Application of kernel principal component analysis and support vector regression for reconstruction of cardiac transmembrane potentials  

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.

114

Polyethylenimine functionalized magnetic nanoparticles as a potential non-viral vector for gene delivery.  

Science.gov (United States)

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

115

Possible physical self-asserting of the homogeneous vector potential. A testing puzzle based on a G.P. Thomson-like arrangement  

CERN Document Server

It is suggested a testing puzzle able to reveal the self-asserting property of the homogeneous vector potential field. As pieces of the puzzle are taken three reliable entities : (i) influence of a potential vector on the de Broglie wavelength (ii) a G.P. Thomson-like experimental arrangement and (iii) a special coil designed to create a homogeneous vector potential. The alluded property is not connected with magnetic fluxes surrounded by the vector potential field lines, but it depends on the fluxes which are outside of the respective lines. Also the same property shows that in the tested case the vector potential field is uniquely defined physical quantity, free of any adjusting gauge. So the phenomenology of the suggested quantum test differs on that of macroscopic theory where the vector potential is not uniquely defined and allows a gauge adjustment. Of course that the proposed test has to be subjected to adequate experimental validation.

Dumitru, Spiridon

2014-01-01

116

Bound states of the Duffin-Kemmer-Petiau equation with a mixed minimal-nonminimal vector cusp potential  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

117

Bound states of the Duffin-Kemmer-Petiau equation with a mixed minimal-nonminimal vector cusp potential  

International Nuclear Information System (INIS)

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.

118

Bound states of the Duffin-Kemmer-Petiau equation with a mixed minimal-nonminimal vector cusp potential  

Science.gov (United States)

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.

de Castro, A. S.

2011-01-01

119

Bound states of the Duffin-Kemmer-Petiau equation with a mixed minimal-nonminimal vector cusp potential  

Energy Technology Data Exchange (ETDEWEB)

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.

De Castro, A S, E-mail: castro@pq.cnpq.br [UNESP-Campus de Guaratingueta, Departamento de Fisica e Quimica, 12516-410 Guaratingueta SP (Brazil)

2011-01-21

120

Investigation of the Buckling-Reactivity Conversion Coefficient using SRAC and MVP codes for UO2 Lattices in TCA experiments  

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)

 
 
 
 
121

Aedes hensilli as a Potential Vector of Chikungunya and Zika Viruses.  

Science.gov (United States)

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

2014-10-01

122

Development of Sendai virus vectors and their potential applications in gene therapy and regenerative medicine.  

Science.gov (United States)

Gene delivery/expression vectors have been used as fundamental technologies in gene therapy since the 1980s. These technologies are also being applied in regenerative medicine as tools to reprogram cell genomes to a pluripotent state and to other cell lineages. Rapid progress in these new research areas and expectations for their translation into clinical applications have facilitated the development of more sophisticated gene delivery/expression technologies. Since its isolation in 1953 in Japan, Sendai virus (SeV) has been widely used as a research tool in cell biology and in industry, but the application of SeV as a recombinant viral vector has been investigated only recently. Recombinant SeV vectors have various unique characteristics, such as low pathogenicity, powerful capacity for gene expression and a wide host range. In addition, the cytoplasmic gene expression mediated by this vector is advantageous for applications, in that chromosomal integration of exogenous genes can be undesirable. In this review, we introduce a brief historical background on the development of recombinant SeV vectors and describe their current applications in gene therapy. We also describe the application of SeV vectors in advanced nuclear reprogramming and introduce a defective and persistent SeV vector (SeVdp) optimized for such reprogramming. PMID:22920683

Nakanishi, Mahito; Otsu, Makoto

2012-10-01

123

Can one directly test the scalar-vector Lorentz structure of the nucleon- and antinucleon-nucleus potential?  

International Nuclear Information System (INIS)

Quantum hadrodynamics in mean-field approximation describes the effective nucleon-nucleus potential (about -50 MeV deep) as resulting from a strong repulsive vector (about 400 MeV) and a strong attractive scalar (about -450 MeV) contribution. This scalar-vector Lorentz structure implies a significant lowering of the threshold for pp-bar photoproduction on a nucleus by about 850 MeV as compared with the free case since charge conjugation reverses the sign of the vector potential contribution in the equation of motion for the p-bar states. We discuss the possibility of measurable signatures of the scalar-vector structure of the nucleon-nucleus potential for the pp-bar photoproduction. The pp-bar photoproduction cross section is calculated for the target nucleus 208Pb near threshold. We indicate the increased cross section for emission of charged pions as a consequence of the subsequent p-bar annihilation within the nucleus. The inclusive cross section for ?-induced pp-bar creation and the resulting increase of charged pion production are probably too small as compared with the expected background to be measurable. (author)

124

Dextran and protamine-based solid lipid nanoparticles as potential vectors for the treatment of X-linked juvenile retinoschisis.  

Science.gov (United States)

The goal of the present study was to analyze the potential application of nonviral vectors based on solid lipid nanoparticles (SLN) for the treatment of ocular diseases by gene therapy, specifically X-linked juvenile retinoschisis (XLRS). Vectors were prepared with SLN, dextran, protamine, and a plasmid (pCMS-EGFP or pCEP4-RS1). Formulations were characterized and the in vitro transfection capacity as well as the cellular uptake and the intracellular trafficking were studied in ARPE-19 cells. Formulations were also tested in vivo in Wistar rat eyes, and the efficacy was studied by monitoring the expression of enhanced green fluorescent protein (EGFP) after intravitreal, subretinal, and topical administration. The presence of dextran and protamine in the SLN improved greatly the expression of retinoschisin and EGFP in ARPE-19 cells. The nuclear localization signals of protamine, its ability to protect the DNA, and a shift in the entry mechanism from caveola-mediated to clathrin-mediated endocytosis promoted by the dextran, justify the increase in transfection. After ocular administration of the dextran-protamine-DNA-SLN complex to rat eyes, we detected the expression of EGFP in various types of cells depending on the administration route. Our vectors were also able to transfect corneal cells after topical application. We have demonstrated the potential usefulness of our nonviral vectors loaded with XLRS1 plasmid and provided evidence for their potential application for the management or treatment of degenerative retinal disorders as well as ocular surface diseases. PMID:22295905

Delgado, Diego; del Pozo-Rodríguez, Ana; Solinís, Maria Ángeles; Avilés-Triqueros, Marcelino; Weber, Bernhard H F; Fernández, Eduardo; Gascón, Alicia R

2012-04-01

125

Nucleus-Nucleus (Non-monotonic Potentials and Vector Analyzing Powers of 6Li Scattering by 16O  

Directory of Open Access Journals (Sweden)

Full Text Available The data on the elastic scattering cross-section (CS and vector analyzing power (VAP of 6Li incident on 16O nuclei is analyzed in terms of an optical model (OM potential, the real part of which is generated from a realistic two-nucleon interaction using the energy-density functional (EDF formalism. The EDF-generated real part of the potential is non-monotonic (NM in nature. This NM real potential part, without any renormalization, along with an emperically determined imaginary part and spin-orbit potential, embodying theunderlying physics of projectile excitation, can successfully account for both CS and VAP data in all cases.

Pretam k. Das, samiron k. Saha

2013-11-01

126

A combined vector potential-scalar potential method for FE computation of 3D magnetic fields in electrical devices with iron cores  

Science.gov (United States)

A method of combined use of magnetic vector potential based finite-element (FE) formulations and magnetic scalar potential (MSP) based formulations for computation of three-dimensional magnetostatic fields is introduced. In this method, the curl-component of the magnetic field intensity is computed by a reduced magnetic vector potential. This field intensity forms the basic of a forcing function for a global magnetic scalar potential solution over the entire volume of the region. This method allows one to include iron portions sandwiched in between conductors within partitioned current-carrying subregions. The method is most suited for large-scale global-type 3-D magnetostatic field computations in electrical devices, and in particular rotating electric machinery.

Wang, R.; Demerdash, N. A.

1991-01-01

127

On the nonminimal vector coupling in the Duffin-Kemmer-Petiau theory and the confinement of massive bosons by a linear potential  

International Nuclear Information System (INIS)

The vector couplings in the Duffin-Kemmer-Petiau (DKP) theory have been revised. It is shown that minimal and nonminimal vector potentials behave differently under charge-conjugation and time-reversal transformations. In particular, it is shown that nonminimal vector potentials have been erroneously applied to the description of elastic meson-nucleus scatterings and that the space component of the nonminimal vector potential plays a crucial role for the confinement of bosons. The DKP equation with nonminimal vector linear potentials is mapped into the nonrelativistic harmonic oscillator problem and the behavior of the solutions for this sort of DKP oscillator is discussed in detail. Furthermore, the absence of Klein's paradox and the localization of bosons in the presence of nonminimal vector interactions are discussed.

128

On the nonminimal vector coupling in the Duffin-Kemmer-Petiau theory and the confinement of massive bosons by a linear potential  

Energy Technology Data Exchange (ETDEWEB)

The vector couplings in the Duffin-Kemmer-Petiau (DKP) theory have been revised. It is shown that minimal and nonminimal vector potentials behave differently under charge-conjugation and time-reversal transformations. In particular, it is shown that nonminimal vector potentials have been erroneously applied to the description of elastic meson-nucleus scatterings and that the space component of the nonminimal vector potential plays a crucial role for the confinement of bosons. The DKP equation with nonminimal vector linear potentials is mapped into the nonrelativistic harmonic oscillator problem and the behavior of the solutions for this sort of DKP oscillator is discussed in detail. Furthermore, the absence of Klein's paradox and the localization of bosons in the presence of nonminimal vector interactions are discussed.

Cardoso, T R; Castro, L B; De Castro, A S, E-mail: cardoso@feg.unesp.b, E-mail: benito@feg.unesp.b, E-mail: castro@pq.cnpq.b [UNESP-Campus de Guaratingueta, Departamento de Fisica e Quimica, 12516-410 Guaratingueta Sao Paulo (Brazil)

2010-02-05

129

On the nonminimal vector coupling in the Duffin-Kemmer-Petiau theory and the confinement of massive bosons by a linear potential  

Science.gov (United States)

The vector couplings in the Duffin-Kemmer-Petiau (DKP) theory have been revised. It is shown that minimal and nonminimal vector potentials behave differently under charge-conjugation and time-reversal transformations. In particular, it is shown that nonminimal vector potentials have been erroneously applied to the description of elastic meson-nucleus scatterings and that the space component of the nonminimal vector potential plays a crucial role for the confinement of bosons. The DKP equation with nonminimal vector linear potentials is mapped into the nonrelativistic harmonic oscillator problem and the behavior of the solutions for this sort of DKP oscillator is discussed in detail. Furthermore, the absence of Klein's paradox and the localization of bosons in the presence of nonminimal vector interactions are discussed.

Cardoso, T. R.; Castro, L. B.; de Castro, A. S.

2010-02-01

130

On the nonminimal vector coupling in the Duffin-Kemmer-Petiau theory and the confinement of massive bosons by a linear potential  

CERN Document Server

Vector couplings in the Duffin-Kemmer-Petiau theory are revised. It is shown that minimal and nonminimal vector potentials behave differently under charge-conjugation and time-reversal transformations. In particular, it is shown that nonminimal vector potentials have been erroneously applied to the description of elastic meson-nucleus scatterings and that the space component of the nonminimal vector potential plays a crucial role for the confinement of bosons. The DKP equation with nonminimal vector linear potentials is mapped into the nonrelativistic harmonic oscillator problem and the behavior of the solutions for this sort of DKP oscillator is discussed in detail. Furthermore, the absence of Klein's paradox and the localization of bosons in the presence of nonminimal vector interactions are discussed.

Cardoso, T R; De Castro, A S

2009-01-01

131

Magnetic field, vector potential, and their partial derivatives due to a current-carrying straight wire of finite length  

International Nuclear Information System (INIS)

A numerical study is made of a problem dealing with calculation of the magnetic field B vector, the magnetic vector potential A vector, and first partial derivatives of the B vector field and A vector components for two kinds of magnetic sources: (1) current-carrying straight wire of finite length; and (2) current-carrying closed polygon. No restrictions are imposed on the type of the polygon and hence it need not be plane and can consist of arbitrary number of straight wires of arbitrary lengths. Separate consideration of the polygon case makes the numerical procedure more efficient than that based on the linear superposition of the straight-wire sources. All necessary quantities are derived analytically in simple and closed forms without use of any approximations and exact relations are utilized to the greatest possible extent to give an efficient algorithm. Thus, the involved numerical procedures are quite simple, fast, accurate, and straightforward. Results are given in four different coordinate systems (cartesian, cylindrical, spherical, and local toroidal) and results in any other orthogonal coordinates can be obtained with only a few minor modifications

132

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

Energy Technology Data Exchange (ETDEWEB)

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 {sup 113}Cd 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 k{sub eff} 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 {sup 113}Cd burn-up becomes pronounced and each k{sub eff} makes a difference after 80. day. (authors)

Komeda, Masao; Yamamoto, Kazuyoshi; Kusunoki, Tsuyoshi [Japan Atomic Energy Agency, Tokai, Ibaraki (Japan)

2008-07-01

133

Potential formulation of the dispersion relation for a uniform, magnetized plasma with stationary ions in terms of a vector phasor  

International Nuclear Information System (INIS)

The derivation of the helicon dispersion relation for a uniform plasma with stationary ions subject to a constant background magnetic field is reexamined in terms of the potential formulation of electrodynamics. Under the same conditions considered by the standard derivation, the nonlinear self-coupling between the perturbed electron flow and the potential it generates is addressed. The plane wave solution for general propagation vector is determined for all frequencies and expressed in terms of a vector phasor. The behavior of the solution as described in vacuum units depends upon the ratio of conductivity to the magnitude of the background field. Only at low conductivity and below, the cyclotron frequency can significant propagation occur as determined by the ratio of skin depth to wavelength.

134

Bose-Einstein condensate in a light-induced vector gauge potential using 1064-nm optical-dipole-trap lasers  

International Nuclear Information System (INIS)

Using two crossed 1064-nm optical-dipole-trap lasers to be the Raman beams, an effective vector gauge potential for Bose-Einstein condensed 87Rb in the F=2 hyperfine ground state is experimentally created. The moderate strength of the Raman coupling still can be achieved when the detuning from atomic resonance is larger than the excited-state fine structure, since rubidium has 15 nm energy-level spitting. The atoms at the far detuning of the Raman coupling are loaded adiabatically into the dressed states by ramping the homogeneous bias magnetic field with different paths and the dressed states with different energies are studied experimentally. The experimental scheme can be easily extended to produce the synthetic magnetic or electric field by means of a spatial or time dependence of the effective vector potential.

135

Phlebotomine sand flies (Diptera, Psychodidae) from Rio de Janeiro State, Brazil: species distribution and potential vectors of leishmaniases  

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.

136

Bose-Einstein condensate in a light-induced vector gauge potential using 1064-nm optical-dipole-trap lasers  

Energy Technology Data Exchange (ETDEWEB)

Using two crossed 1064-nm optical-dipole-trap lasers to be the Raman beams, an effective vector gauge potential for Bose-Einstein condensed {sup 87}Rb in the F=2 hyperfine ground state is experimentally created. The moderate strength of the Raman coupling still can be achieved when the detuning from atomic resonance is larger than the excited-state fine structure, since rubidium has 15 nm energy-level spitting. The atoms at the far detuning of the Raman coupling are loaded adiabatically into the dressed states by ramping the homogeneous bias magnetic field with different paths and the dressed states with different energies are studied experimentally. The experimental scheme can be easily extended to produce the synthetic magnetic or electric field by means of a spatial or time dependence of the effective vector potential.

Fu Zhengkun; Wang Pengjun; Chai Shijie; Huang Lianghui; Zhang Jing [State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China)

2011-10-15

137

Symbolic Computation and Graphic Presentation of Magneto-Static Field and Its Associated Vector Potential for a Steady Looping Current  

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

138

Bovine herpesvirus 4 based vector as a potential oncolytic-virus for treatment of glioma  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract The application of gene therapy for malignant gliomas is still under study and the use of specific vectors represents an important contribution. Here, we investigated bovine herpesvirus 4 (BoHV-4), which is non-pathogenic if injected into the rodent brain. We show that the vector can infect mouse, rat and human glioma cell lines and primary cultures obtained from human glioblastoma in vitro. BoHV-4 was injected into a tumour grown in rat brain. Although virus expression was...

Avella Domenico, D.; Caretta Antonio; Cavaggioni Andrea; Mucignat-Caretta Carla; Redaelli Marco; Denaro Luca; Cavirani Sandro; Donofrio Gaetano

2010-01-01

139

Any J-state solution of the DKP equation for a vector deformed Woods-Saxon potential  

Digital Repository Infrastructure Vision for European Research (DRIVER)

By using the Pekeris approximation, the Duffin-Kemmer-Petiau (DKP) equation is investigated for a vector deformed Woods-Saxon (dWS) potential. The parametric Nikiforov-Uvarov (NU) method is used in calculations. The approximate energy eigenvalue equation and the corresponding wave function spinor components are calculated for any total angular momentum J in closed form. The exact energy equation and wave function spinor components are also given for the J=0 case. We use a se...

Hamzavi, Majid; Ikhdair, Sameer M.

2012-01-01

140

Approximate solution of the Duffin-Kemmer-Petiau equation for a vector Yukawa potential with arbitrary total angular momenta  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

 
 
 
 
141

The potential of classic and specific bioelectrical impedance vector analysis for the assessment of sarcopenia and sarcopenic obesity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Elisabetta Marini,1 Roberto Buffa,1 Bruno Saragat,1 Alessandra Coin,2 Elena Debora Toffanello,2 Linda Berton,2 Enzo Manzato,2 Giuseppe Sergi21Department of Environmental and Life Sciences, University of Cagliari, Italy; 2Department of Medicine-DIMED, Geriatrics Section, University of Padua, ItalyPurpose: The aim of this paper is to investigate whether bioelectrical impedance vector analysis (BIVA) can be a suitable technique for the assessment of sarcopenia. We also investigate the potential ...

Marini E; Buffa R; Saragat B; Coin A; Ed, Toffanello; Berton L; Manzato E; Sergi G

2012-01-01

142

Survey of potential sharpshooter and spittlebug vectors of Xylella fastidiosa to grapevines at the São Francisco River Valley, Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Survey of potential sharpshooter and spittlebug vectors of Xylella fastidiosa to grapevines at the São Francisco River Valley, Brazil. Pierce's disease of grapevines, caused by Xylella fastidiosa, is a serious problem in some regions of North America, not yet reported in Brazil. In this study, a sur [...] vey of potential sharpshooter (Hemiptera, Cicadellidae, Cicadellinae) and spittlebug (Hemiptera, Cercopidae) vectors of X. fastidiosa was conducted in vineyards at the São Francisco River Valley, a major grape growing region in Brazil. Four vineyards of Vitis vinifera L. were sampled fortnightly from June/2005 to June/2007, using yellow sticky cards, each placed at two different heights (45 cm aboveground and 45 cm above the crop canopy) in 10 sampling localities. A total of 4,095 specimens of sharpshooters were collected, nearly all from 3 Proconiini species, Homalodisca spottii Takiya, Cavichioli & McKamey, 2006 (96.8% of the specimens), Tapajosa fulvopunctata (Signoret, 1854) (3.1%), and Tretogonia cribrata Melichar, 1926 (1 specimen). Hortensia similis (Walker, 1851) (2 specimens) was the only Cicadellini species. Only 1 cercopid specimen, belonging to Aeneolamia colon (Germar, 1821), was trapped. Even though they are not considered potential Xylella vectors, 2 Gyponini leafhoppers were collected: Curtara samera DeLong & Freytag, 1972 (11 specimens) and Curtara inflata DeLong & Freytag, 1976 (1 specimen). Homalodisca spottii was observed feeding and mating on green branches of grapevines, in addition to egg masses. Because of its prevalence on the crop canopy, occurrence throughout the year (with peaks from February to August), and ability to colonize grapevines, H. spottii could be an important vector if a X. fastidiosa strain pathogenic to grapevines becomes introduced at the São Francisco River Valley.

Rudiney, Ringenberg; João Roberto Spotti, Lopes; Cristiane, Müller; Wilson Sampaio de, Azevedo-Filho; Beatriz Aguiar Jordão, Paranhos; Marcos, Botton.

2014-06-01

143

Survey of potential sharpshooter and spittlebug vectors of Xylella fastidiosa to grapevines at the São Francisco River Valley, Brazil  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Survey of potential sharpshooter and spittlebug vectors of Xylella fastidiosa to grapevines at the São Francisco River Valley, Brazil. Pierce's disease of grapevines, caused by Xylella fastidiosa, is a serious problem in some regions of North America, not yet reported in Brazil. In this study, a sur [...] vey of potential sharpshooter (Hemiptera, Cicadellidae, Cicadellinae) and spittlebug (Hemiptera, Cercopidae) vectors of X. fastidiosa was conducted in vineyards at the São Francisco River Valley, a major grape growing region in Brazil. Four vineyards of Vitis vinifera L. were sampled fortnightly from June/2005 to June/2007, using yellow sticky cards, each placed at two different heights (45 cm aboveground and 45 cm above the crop canopy) in 10 sampling localities. A total of 4,095 specimens of sharpshooters were collected, nearly all from 3 Proconiini species, Homalodisca spottii Takiya, Cavichioli & McKamey, 2006 (96.8% of the specimens), Tapajosa fulvopunctata (Signoret, 1854) (3.1%), and Tretogonia cribrata Melichar, 1926 (1 specimen). Hortensia similis (Walker, 1851) (2 specimens) was the only Cicadellini species. Only 1 cercopid specimen, belonging to Aeneolamia colon (Germar, 1821), was trapped. Even though they are not considered potential Xylella vectors, 2 Gyponini leafhoppers were collected: Curtara samera DeLong & Freytag, 1972 (11 specimens) and Curtara inflata DeLong & Freytag, 1976 (1 specimen). Homalodisca spottii was observed feeding and mating on green branches of grapevines, in addition to egg masses. Because of its prevalence on the crop canopy, occurrence throughout the year (with peaks from February to August), and ability to colonize grapevines, H. spottii could be an important vector if a X. fastidiosa strain pathogenic to grapevines becomes introduced at the São Francisco River Valley.

Rudiney, Ringenberg; João Roberto Spotti, Lopes; Cristiane, Müller; Wilson Sampaio de, Azevedo-Filho; Beatriz Aguiar Jordão, Paranhos; Marcos, Botton.

144

Any J-State Solution of the Duffin-Kemmer-Petiau Equation for a Vector Deformed Woods-Saxon Potential  

Science.gov (United States)

By using the Pekeris approximation, the Duffin-Kemmer-Petiau (DKP) equation is investigated for a vector deformed Woods-Saxon (dWS) potential. The parametric Nikiforov-Uvarov (NU) method is used in calculations. The approximate energy eigenvalue equation and the corresponding wave function spinor components are calculated for any total angular momentum J in closed form. The exact energy equation and wave function spinor components are also given for the J = 0 case. We use a set of parameter values to obtain the numerical values for the energy states with various values of quantum levels ( n, J) and potential's deformation constant q and width R.

Hamzavi, M.; Ikhdair, S. M.

2012-10-01

145

Overcoming drug resistance of MCF-7/ADR cells by altering intracellular distribution of doxorubicin via MVP knockdown with a novel siRNA polyamidoamine-hyaluronic acid complex.  

Science.gov (United States)

Drug resistance is one of the critical reasons leading to failure in chemotherapy. Enormous studies have been focused on increasing intracellular drug accumulation through inhibiting P-glycoprotein (Pgp). Meanwhile, we found that major vault protein (MVP) may be also involved in drug resistance of human breast cancer MCF-7/ADR cells by transporting doxorubicin (DOX) from the action target (i.e. nucleus) to cytoplasma. Herein polyamidoamine (PAMAM) dendrimers was functionalized by a polysaccharide hyaluronic acid (HA) to effectively deliver DOX as well as MVP targeted small-interfering RNA (MVP-siRNA) to down regulate MVP expression and improve DOX chemotherapy in MCF-7/ADR cells. In comparison with DOX solution (IC50=48.5 ?M), an enhanced cytotoxicity could be observed for DOX PAMAM-HA (IC50=11.3 ?M) as well as enhanced tumor target, higher intracellular accumulation, increased blood circulating time and less in vivo toxicity. Furthermore, codelivery of siRNA and DOX by PAMAM-HA exhibited satisfactory gene silencing effect as well as enhanced stability and efficient intracellular delivery of siRNA, which allowed DOX access to nucleus and induced subsequent much more cytotoxicity than siRNA absent case as a result of MVP knockdown. This observation highlights a promising application of novel nanocarrier PAMAM-HA, which could co-deliver anticancer drug and siRNA, in reversing drug resistance by altering intracellular drug distribution. PMID:22940126

Han, Min; Lv, Qing; Tang, Xin-Jiang; Hu, Yu-Lan; Xu, Dong-Hang; Li, Fan-Zhu; Liang, Wen-Quan; Gao, Jian-Qing

2012-10-28

146

Measurement of the depolarization of the reaction 27Al(p vector,p vector.)27Al for the study of the spin-spin potential  

International Nuclear Information System (INIS)

For the study of the spin-spin interaction in the optical potential the depolarisation in the elastic scattering of polarized protons was measured. The double-scattering experiments were performed in the angular range 400-1100 at an incident energy of 10.35 MeV at the Erlangen QD-magnetic spectrometer. The determination of the optical model parameters independent from the spin-spin potentials was performed by the fitting of these to the observables and sigmasup(di). These were obtained from a measurement of the angular distribution of the analyzing power and the differential cross section in the 4?-scattering chamber for the reaction 27Al(p vector,p0) at the same energy. The compound contributions present at this energy, which can also influence the depolarization, were regarded by the calculation of the compound-elastic non-spin-flip respectively spin-flip subcross sections by means of the formalism of Hofmann, Richert, Tepel and Weidenmueller. Because the target nucleus 27Al possesses in the ground state a spin I=5/2, also the possible quadrupole spin flip had to be included. This was performed by coupled-channel calculations. The respecting compound contributions and quadrupole effects corrected depolarization data could by used for the study of the spin-spin potentials by means of DWBA calculations. As result it was shown that for the description of the experimental data a spherical spin-spin potential of the strength Vsub(SS)=1.5+-0.3 MeV had to be assumed. (orig.)

147

West Nile Virus Transmission in Sentinel Chickens and Potential Mosquito Vectors, Senegal River Delta, 2008-2009  

Science.gov (United States)

West Nile virus (WNV) is an arthropod-borne Flavivirus usually transmitted to wild birds by Culex mosquitoes. Humans and horses are susceptible to WNV but are dead-end hosts. WNV is endemic in Senegal, particularly in the Senegal River Delta. To assess transmission patterns and potential vectors, entomological and sentinel serological was done in Ross Bethio along the River Senegal. Three sentinel henhouses (also used as chicken-baited traps) were set at 100 m, 800 m, and 1,300 m from the river, the latter close to a horse-baited trap. Blood samples were taken from sentinel chickens at 2-week intervals. Seroconversions were observed in sentinel chickens in November and December. Overall, the serological incidence rate was 4.6% with 95% confidence interval (0.9; 8.4) in the sentinel chickens monitored for this study. Based on abundance pattern, Culex neavei was the most likely mosquito vector involved in WNV transmission to sentinel chickens, and a potential bridge vector between birds and mammals. PMID:24084679

Fall, Assane Gueye; Diaite, Amadou; Seck, Momar Talla; Bouyer, Jeremy; Lefrancois, Thierry; Vachiery, Nathalie; Aprelon, Rosalie; Faye, Ousmane; Konate, Lassana; Lancelot, Renaud

2013-01-01

148

West Nile Virus Transmission in Sentinel Chickens and Potential Mosquito Vectors, Senegal River Delta, 2008–2009  

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Full Text Available West Nile virus (WNV is an arthropod-borne Flavivirus usually transmitted to wild birds by Culex mosquitoes. Humans and horses are susceptible to WNV but are dead-end hosts. WNV is endemic in Senegal, particularly in the Senegal River Delta. To assess transmission patterns and potential vectors, entomological and sentinel serological was done in Ross Bethio along the River Senegal. Three sentinel henhouses (also used as chicken-baited traps were set at 100 m, 800 m, and 1,300 m from the river, the latter close to a horse-baited trap. Blood samples were taken from sentinel chickens at 2-week intervals. Seroconversions were observed in sentinel chickens in November and December. Overall, the serological incidence rate was 4.6% with 95% confidence interval (0.9; 8.4 in the sentinel chickens monitored for this study. Based on abundance pattern, Culex neavei was the most likely mosquito vector involved in WNV transmission to sentinel chickens, and a potential bridge vector between birds and mammals.

Renaud Lancelot

2013-10-01

149

Dengue vectors, human activity, and dengue virus transmission potential in the lower Rio Grande Valley, Texas, United States.  

Science.gov (United States)

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

150

West Nile virus transmission in sentinel chickens and potential mosquito vectors, Senegal River Delta, 2008-2009.  

Science.gov (United States)

West Nile virus (WNV) is an arthropod-borne Flavivirus usually transmitted to wild birds by Culex mosquitoes. Humans and horses are susceptible to WNV but are dead-end hosts. WNV is endemic in Senegal, particularly in the Senegal River Delta. To assess transmission patterns and potential vectors, entomological and sentinel serological was done in Ross Bethio along the River Senegal. Three sentinel henhouses (also used as chicken-baited traps) were set at 100 m, 800 m, and 1,300 m from the river, the latter close to a horse-baited trap. Blood samples were taken from sentinel chickens at 2-week intervals. Seroconversions were observed in sentinel chickens in November and December. Overall, the serological incidence rate was 4.6% with 95% confidence interval (0.9; 8.4) in the sentinel chickens monitored for this study. Based on abundance pattern, Culex neavei was the most likely mosquito vector involved in WNV transmission to sentinel chickens, and a potential bridge vector between birds and mammals. PMID:24084679

Fall, Assane Gueye; Diaïté, Amadou; Seck, Momar Talla; Bouyer, Jérémy; Lefrançois, Thierry; Vachiéry, Nathalie; Aprelon, Rosalie; Faye, Ousmane; Konaté, Lassana; Lancelot, Renaud

2013-10-01

151

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

152

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.)

153

The distribution of potential West Nile virus vectors, Culex pipiens pipiens and Culex pipiens quinquefasciatus (Diptera: Culicidae, in Mexico City  

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

154

The potential of a new larviciding method for the control of malaria vectors  

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Full Text Available Abstract Malaria pathogens are transmitted to humans by the bite of female Anopheles mosquitoes. The juvenile stages of these mosquitoes develop in a variety of water bodies and are key targets for vector control campaigns involving the application of larvicides. The effective operational implementation of these campaigns is difficult, time consuming, and expensive. New evidence however, suggests that adult mosquitoes can be co-opted into disseminating larvicides in a far more targeted and efficient manner than can be achieved using conventional methods.

Devine Gregor J

2010-05-01

155

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

156

How often do they meet? Genetic similarity between European populations of a potential disease vector Culex pipiens  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Species in the Culex pipiens complex are common almost all over the world and represent important vectors for many serious zoonotic diseases. Even if, at the moment, many of the pathogens potentially transmitted by Cx. pipiens are not a problem in northern Europe, they may, with increasing temperatures and changing ecosystems caused by climate change, move northward in the future. Therefore, the question whether or not the Cx. pipiens populations in northern Europe will be competent vectors for them is of high importance. One way to estimate the similarity and the rate of contact between European Cx. pipiens populations is to look at the gene exchange between these populations. Methods: To test the genetic diversity and degree of differentiation between European Cx. pipiens populations, we used eight microsatellite markers in 10 mosquito populations originating from northern, central, and southern Europe. Results: We found that three of the analyzed populations were very different from the rest of the populations and they also greatly differed from each other. When these three populations were removed, the variance among the rest of the populations was low, suggesting an extensive historic gene flow between many European Cx. pipiens populations. Conclusions: This suggests that infectious diseases spread by this species may not be associated with a certain vector genotype but rather with suitable environmental conditions. Consequently, we would expect these pathogens to disperse northward with favorable climatic parameters.

Mare Lõhmus

2012-08-01

157

Developing a potentially immunologically inert tetracycline-regulatable viral vector for gene therapy in the peripheral nerve.  

Science.gov (United States)

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

158

Biting behaviour and biting rhythm of potential Japanese encephalitis vectors in Assam.  

Science.gov (United States)

Studies on biting behaviour and biting cycles of medically important mosquitoes were carried out in Madhupur village and Tarajan tea estate of upper Assam. Collections were made off human baits outdoors and indoors and off cattle bait outdoors from August 1991 to July 1992. Human bait collections were performed using the 'stationary direct bait' technique. A total of 9,072 adult host seeking female mosquitoes representing 26 species and 5 genera were collected off baits of which 36.9% were collected off human baits and the rest from cattle. All mosquitoes were primarily zoophilic, although significant numbers were collected biting man outdoors. Biting preferences of important Japanese encephalitis (JE) vectors for man and cattle were studied using outdoor man:outdoor cattle ratio (attraction ratio = AR). Culex quinquefasciatus was attracted towards human baits the most (AR = 8.1:1), followed by Cx. bitaeniorhynchus (AR = 1.6:1) and Mansonia annulifera (AR = 1.3.1). The hourly biting activity of important JE vectors throughout the night on two bait types was also studied using three point moving averages. Hierarchical agglomerative cluster analysis was used to compare and classify mosquitoes on the basis of their similarity in biting rhythms. PMID:9282509

Khan, S A; Narain, K; Dutta, P; Handique, R; Srivastava, V K; Mahanta, J

1997-06-01

159

Vectorization, parallelization and porting of nuclear codes (vectorization and parallelization). Progress report fiscal 1998  

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)

160

Vectorization, parallelization and porting of nuclear codes (vectorization and parallelization). Progress report fiscal 1998  

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

 
 
 
 
161

Analysis of one month of CHAMP state vector and accelerometer data for the recovery of the gravity potential  

Directory of Open Access Journals (Sweden)

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

162

Analysis of one month of CHAMP state vector and accelerometer data for the recovery of the gravity potential  

DEFF Research Database (Denmark)

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. Keyword: Energy conservation,CHAMP,Gravity field model,Collocation

Howe, E; Stenseng, Lars

2003-01-01

163

Survey of cyclopids (Crustacea, Copepoda in Brazil and preliminary screening of their potential as dengue vector predators  

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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

164

Finite element formulation using magnetic vector potential approach: effects of displacement current in magneto-electro-elastic cylindrical shells  

Science.gov (United States)

Displacement current is associated with the generation of magnetic fields due to time-varying electric fields. The harmonic response of a magneto-electro-elastic axisymmetric cylinder accounting for displacement current is carried out using the semi-analytical finite element method. The non-conservative electric field is represented using a magnetic vector potential. Studies are carried out for the first circumferential harmonics of the shell structure with the clamped-free boundary condition. The contribution made to the magnetic flux density by the electric displacement current is very small at lower frequencies but it becomes significant at higher frequencies.

Biju, B.; Ganesan, N.; Shankar, K.

2010-01-01

165

Finite element formulation using magnetic vector potential approach: effects of displacement current in magneto-electro-elastic cylindrical shells  

International Nuclear Information System (INIS)

Displacement current is associated with the generation of magnetic fields due to time-varying electric fields. The harmonic response of a magneto-electro-elastic axisymmetric cylinder accounting for displacement current is carried out using the semi-analytical finite element method. The non-conservative electric field is represented using a magnetic vector potential. Studies are carried out for the first circumferential harmonics of the shell structure with the clamped–free boundary condition. The contribution made to the magnetic flux density by the electric displacement current is very small at lower frequencies but it becomes significant at higher frequencies

166

Approximate Solution of the Duffin-Kemmer-Petiau Equation for a Vector Yukawa Potential with Arbitrary Total Angular Momenta  

Science.gov (United States)

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).

Hamzavi, M.; Ikhdair, S. M.

2013-11-01

167

Approximate Solution of the Duffin–Kemmer–Petiau Equation for a Vector Yukawa Potential with Arbitrary Total Angular Momenta  

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)

168

Approximate solution of the Duffin-Kemmer-Petiau equation for a vector Yukawa potential with arbitrary total angular momenta  

CERN Document Server

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 parameter values is used to obtain the numerical values for the energy states with various values of quantum levels

Hamzavi, Majid

2012-01-01

169

West Nile Virus Transmission in Sentinel Chickens and Potential Mosquito Vectors, Senegal River Delta, 2008-2009  

Digital Repository Infrastructure Vision for European Research (DRIVER)

West Nile virus (WNV) is an arthropod-borne Flavivirus usually transmitted to wild birds by Culex mosquitoes. Humans and horses are susceptible to WNV but are dead-end hosts. WNV is endemic in Senegal, particularly in the Senegal River Delta. To assess transmission patterns and potential vectors, entomological and sentinel serological was done in Ross Bethio along the River Senegal. Three sentinel henhouses (also used as chicken-baited traps) were set at 100 m, 800 m, and 1,300 m from the riv...

Renaud Lancelot; Ousmane Faye; Lassana Konaté; Nathalie Vachiéry; Rosalie Aprelon; Jérémy Bouyer; Momar Talla Seck; Thierry Lefrançois; Amadou Diaïté; Assane Gueye Fall

2013-01-01

170

Verification study of thorium cross section in MVP calculation of thorium based fuel core using experimental data  

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)

171

su(1,1) Algebraic approach of the Dirac equation with Coulomb-type scalar and vector potentials in D + 1 dimensions  

CERN Document Server

We study the Dirac equation with Coulomb-type vector and scalar potentials in D + 1 dimensions from an su(1, 1) algebraic approach. The generators of this algebra are constructed by using the Schr\\"odinger factorization. The theory of unitary representations for the su(1, 1) Lie algebra allows us to obtain the energy spectrum and the supersymmetric ground state. For the cases where there exists either scalar or vector potential our results are reduced to those obtained by analytical techniques.

Salazar-Ramírez, M; Mota, R D; Granados, V D

2011-01-01

172

Leafhoppers and Cixiids in Phytoplasma-infected Carrot Fields: Species Composition and Potential Phytoplasma Vectors  

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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

173

Global warming and the potential spread of vector-borne diseases  

Energy Technology Data Exchange (ETDEWEB)

Climatic factors influence many vector-borne infectious diseases, in addition to demographic, biological, and ecological determinants. The United Nation`s Intergovernmental Panel on Climate Change (IPCC) estimates an unprecedented global rise of 2.0 C by the year 2100. Of major concern is that these changes can affect the spread of many serious infectious diseases, including malaria and dengue fever. Global warming would directly affect disease transmission by shifting the mosquito`s geographic range, increasing reproductive and biting rates, and shortening pathogen incubation period. Human migration and damage to health infrastructures from the projected increase in climate variability and sea level rise could indirectly contribute to disease transmission. A review of this literature, as well as preliminary data from ongoing studies will be presented.

Patz, J. [Johns Hopkins School of Hygiene and Public Health, Baltimore, MD (United States). Dept. of Microbiology and Immunology

1996-12-31

174

Global climate change and its potential impact on disease transmission by salinity-tolerant mosquito vectors in coastal zones  

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Full Text Available Global climate change can potentially increase the transmission of mosquito vector-borne diseases such as malaria, lymphatic filariasis and dengue in many parts of the world. These predictions are based on the effects of changing temperature, rainfall and humidity on mosquito breeding and survival, the more rapid development of ingested pathogens in mosquitoes and the more frequent blood feeds at moderately higher ambient temperatures. An expansion of saline and brackish water bodies (water with <0.5 ppt or parts per thousand, 0.5–30 ppt and >30 ppt salt are termed fresh, brackish and saline respectively will also take place as a result of global warming causing a rise in sea levels in coastal zones. Its possible impact on the transmission of mosquito-borne diseases has, however, not been adequately appreciated. The relevant impacts of global climate change on the transmission of mosquito-borne diseases in coastal zones are discussed with reference to the Ross-McDonald equation and modeling studies. Evidence is presented to show that an expansion of brackish water bodies in coastal zones can increase densities of salinity-tolerant mosquitoes like Anopheles sundaicus and Culex sitiens, and lead to the adaptation of fresh water mosquito vectors like Anopheles culicifacies, Anopheles stephensi, Aedes aegypti and Aedes albopictus to salinity. Rising sea levels may therefore act synergistically with global climate change to increase the transmission of mosquito-borne diseases in coastal zones. Greater attention therefore needs to be devoted to monitoring disease incidence and preimaginal development of vector mosquitoes in artificial and natural coastal brackish/saline habitats. It is important that national and international health agencies are aware of the increased risk of mosquito-borne diseases in coastal zones and develop preventive and mitigating strategies. Application of appropriate counter measures can greatly reduce the potential for increased coastal

RanjanRamasamy

2012-06-01

175

Curl-free vector potential observation on the macro-scale and a new dimension to the Lorentz trajectory  

Science.gov (United States)

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.

Varma, Ram K.

2013-09-01

176

Ecological niche modelling of potential west nile virus vector mosquito species and their geographical association with equine epizootics in Italy.  

Science.gov (United States)

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

2014-03-01

177

Predicting distribution of Aedes aegypti and Culex pipiens complex, potential vectors of Rift Valley fever virus in relation to disease epidemics in East Africa  

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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

178

Anopheles plumbeus (Diptera: Culicidae in Europe: a mere nuisance mosquito or potential malaria vector?  

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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

179

Global Climate Change and Its Potential Impact on Disease Transmission by Salinity-Tolerant Mosquito Vectors in Coastal Zones  

Science.gov (United States)

Global climate change can potentially increase the transmission of mosquito vector-borne diseases such as malaria, lymphatic filariasis, and dengue in many parts of the world. These predictions are based on the effects of changing temperature, rainfall, and humidity on mosquito breeding and survival, the more rapid development of ingested pathogens in mosquitoes and the more frequent blood feeds at moderately higher ambient temperatures. An expansion of saline and brackish water bodies (water with 30?ppt salt are termed fresh, brackish, and saline respectively) will also take place as a result of global warming causing a rise in sea levels in coastal zones. Its possible impact on the transmission of mosquito-borne diseases has, however, not been adequately appreciated. The relevant impacts of global climate change on the transmission of mosquito-borne diseases in coastal zones are discussed with reference to the Ross–McDonald equation and modeling studies. Evidence is presented to show that an expansion of brackish water bodies in coastal zones can increase the densities of salinity-tolerant mosquitoes like Anopheles sundaicus and Culex sitiens, and lead to the adaptation of fresh water mosquito vectors like Anopheles culicifacies, Anopheles stephensi, Aedes aegypti, and Aedes albopictus to salinity. Rising sea levels may therefore act synergistically with global climate change to increase the transmission of mosquito-borne diseases in coastal zones. Greater attention therefore needs to be devoted to monitoring disease incidence and preimaginal development of vector mosquitoes in artificial and natural coastal brackish/saline habitats. It is important that national and international health agencies are aware of the increased risk of mosquito-borne diseases in coastal zones and develop preventive and mitigating strategies. Application of appropriate counter measures can greatly reduce the potential for increased coastal transmission of mosquito-borne diseases consequent to climate change and a rise in sea levels. It is proposed that the Jaffna peninsula in Sri Lanka may be a useful case study for the impact of rising sea levels on mosquito vectors in tropical coasts. PMID:22723781

Ramasamy, Ranjan; Surendran, Sinnathamby Noble

2012-01-01

180

Scalar–vector–pseudoscalar Cornell potential for a spin-1/2 particle under spin and pseudospin symmetries: 1+1 dimensions  

Energy Technology Data Exchange (ETDEWEB)

The Cornell potential consists of Coulomb and linear potentials, i.e. ?a/x+bx, that has received a great deal of attention in particle and nuclear physics. In this paper, we present exact solutions of the Dirac equation with the mixed scalar–vector–pseudoscalar Cornell potential under spin and pseudospin symmetry limits. The corresponding eigenfunctions are given in the form of the biconfluent Heun polynomials. -- Highlights: •We investigate the Dirac equation with the scalar–vector–pseudoscalar Cornell potential. •The solutions are discussed in view of spin and pseudospin symmetry limits. •The energy levels and the wave function are presented in Heun biconfluent equations.

Hamzavi, M., E-mail: majid.hamzavi@gmail.com; Rajabi, A.A.

2013-07-15

 
 
 
 
181

Scalar–vector–pseudoscalar Cornell potential for a spin-1/2 particle under spin and pseudospin symmetries: 1+1 dimensions  

International Nuclear Information System (INIS)

The Cornell potential consists of Coulomb and linear potentials, i.e. ?a/x+bx, that has received a great deal of attention in particle and nuclear physics. In this paper, we present exact solutions of the Dirac equation with the mixed scalar–vector–pseudoscalar Cornell potential under spin and pseudospin symmetry limits. The corresponding eigenfunctions are given in the form of the biconfluent Heun polynomials. -- Highlights: •We investigate the Dirac equation with the scalar–vector–pseudoscalar Cornell potential. •The solutions are discussed in view of spin and pseudospin symmetry limits. •The energy levels and the wave function are presented in Heun biconfluent equations

182

Preprocessing the Photospheric Vector Magnetograms for an NLFFF Extrapolation Using a Potential-Field Model and an Optimization Method  

Science.gov (United States)

Numerical reconstruction/extrapolation of the coronal nonlinear force-free magnetic field (NLFFF) usually takes the photospheric vector magnetogram as input at the bottom boundary. The magnetic field observed at the photosphere, however, contains a force that is in conflict with the fundamental assumption of the force-free model. It also contains measurement noise, which hinders the practical computation. Wiegelmann, Inhester, and Sakurai ( Solar Phys. 233, 215, 2006) have proposed to preprocess the raw magnetogram to remove the force and noise to provide better input for NLFFF modeling. In this paper we develop a new code of magnetogram preprocessing that is consistent with our extrapolation method CESE-MHD-NLFFF (Jiang, Feng, and Xiang in Astrophys. J. 755, 62, 2012; Jiang and Feng in Astrophys. J. 749, 135, 2012a). Based on the magnetic-splitting rule that a magnetic field can be split into a potential-field part and a non-potential part, we split the magnetogram and dealt with the two parts separately. The preprocessing of the magnetogram's potential part is based on a numerical potential-field model, and the non-potential part is preprocessed using the similar optimization method of Wiegelmann, Inhester, and Sakurai (2006). The code was applied to the SDO/HMI data, and results show that the method can remove the force and noise efficiently and improve the extrapolation quality.

Jiang, Chaowei; Feng, Xueshang

2014-01-01

183

Validation of a continuous-energy Monte Carlo burn-up code MVP-BURN and its application to analysis of post irradiation experiment  

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)

184

Comparison of osteogenic potentials of human rat BMP4 and BMP6 gene therapy using [E1-] and [E1-,E2b-] adenoviral vectors  

Directory of Open Access Journals (Sweden)

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

185

Larvivorous Potential of Different Stages of Culex tigripes (Diptera, Culicidae in the Prospective of its Use in Biological Control of Malaria Vectors  

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Full Text Available Carried out in the laboratory, the present study tends to assess the larvivorous potential of different stages of Culex tigripes against malaria vectors. The four stages of C. tigripes have effectively a larvivorous activity and may be used in the biological control of mosquito larvae, vector of malaria. Neither lower or higher larval density, large or small size of larvae nor any position pattern of prey larvae from the water surface do inhibit the larvivorous behaviour of C. tigripes.

Basabose, K.

1996-01-01

186

Linking land cover and species distribution models to project potential ranges of malaria vectors: an example using Anopheles arabiensis in Sudan and Upper Egypt  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 c...

Fuller Douglas O; Parenti Michael S; Hassan Ali N; Beier John C

2012-01-01

187

On the effects of grid ill-conditioning in three dimensional finite element vector potential magnetostatic field computations  

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The effects of finite element grid geometries and associated ill-conditioning were studied in single medium and multi-media (air-iron) three dimensional magnetostatic field computation problems. The sensitivities of these 3D field computations to finite element grid geometries were investigated. It was found that in single medium applications the unconstrained magnetic vector potential curl-curl formulation in conjunction with first order finite elements produce global results which are almost totally insensitive to grid geometries. However, it was found that in multi-media (air-iron) applications first order finite element results are sensitive to grid geometries and consequent elemental shape ill-conditioning. These sensitivities were almost totally eliminated by means of the use of second order finite elements in the field computation algorithms. Practical examples are given in this paper to demonstrate these aspects mentioned above.

Wang, R.; Demerdash, N. A.

1990-01-01

188

Electromagnetic Coulomb gas with vector charges and 'elastic' potentials: Renormalization group equations  

International Nuclear Information System (INIS)

We present a detailed derivation of the renormalization group equations for two-dimensional electromagnetic Coulomb gases whose charges lie on a triangular lattice (magnetic charges) and its dual (electric charges). The interactions between the charges involve both angular couplings and a new electromagnetic potential. This motivates the denomination of 'elastic' Coulomb gas. Such elastic Coulomb gases arise naturally in the study of the continuous melting transition of two-dimensional solids coupled to a substrate, either commensurate or with quenched disorder

189

Potential transmission of West Nile virus in the British Isles: an ecological review of candidate mosquito bridge vectors.  

Science.gov (United States)

West Nile virus (WNV) transmitted by mosquitoes (Diptera: Culicidae) infects various vertebrates, being pathogenic for birds, horses and humans. After its discovery in tropical Africa, sporadic outbreaks of WNV occurred during recent decades in Eurasia, but not the British Isles. WNV reached New York in 1999 and spread to California by 2003, causing widespread outbreaks of West Nile encephalitis across North America, transmitted by many species of mosquitoes, mainly Culex spp. The periodic reappearance of WNV in parts of continental Europe (from southern France to Romania) gives rise to concern over the possibility of WNV invading the British Isles. The British Isles have about 30 endemic mosquito species, several with seasonal abundance and other eco-behavioural characteristics predisposing them to serve as potential WNV bridge vectors from birds to humans. These include: the predominantly ornithophilic Culex pipiens L. and its anthropophilic biotype molestus Forskal; tree-hole adapted Anopheles plumbeus Stephens; saltmarsh-adapted Ochlerotatus caspius Pallas, Oc. detritus Haliday and Oc. dorsalis (Meigen); Coquillettidia richiardii Ficalbi, Culiseta annulata Schrank and Cs. morsitans (Theobald) from vegetated freshwater pools; Aedes cinereus Meigen, Oc. cantans Meigen and Oc. punctor Kirby from seasonal woodland pools. Those underlined have been found carrying WNV in other countries (12 species), including the rarer British species Aedes vexans (Meigen), Culex europaeus Ramos et al., Cx. modestus Ficalbi and Oc. sticticus (Meigen) as well as the Anopheles maculipennis Meigen complex (mainly An. atroparvus van Thiel and An. messeae Falleroni in Britain). Those implicated as key vectors of WNV in Europe are printed bold (four species). So far there is no proof of any arbovirus transmission by mosquitoes in the British Isles, although antibodies to Sindbis, Tahyna, Usutu and West Nile viruses have been detected in British birds. Neighbouring European countries have enzootic WNV and human infections transmitted by mosquito species that are present in the British Isles. However, except for localized urban infestations of Cx. pipiens biotype molestus that can be readily eliminated, there appear to be few situations in the British Isles where humans and livestock are exposed to sustained risks of exposure to potential WNV vectors. Monitoring of mosquitoes and arbovirus surveillance are required to guard the British Isles against WNV outbreaks and introduction of more anthropophilic mosquitoes such as Stegomyia albopicta (Skuse) and Ochlerotatus japonicus (Theobald) that have recently invaded Europe, since they transmit arboviruses elsewhere. PMID:15752172

Medlock, J M; Snow, K R; Leach, S

2005-03-01

190

Electromagnetic Coulomb gas with vector charges and 'elastic' potentials: Renormalization group equations  

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We present a detailed derivation of the renormalization group equations for two-dimensional electromagnetic Coulomb gases whose charges lie on a triangular lattice (magnetic charges) and its dual (electric charges). The interactions between the charges involve both angular couplings and a new electromagnetic potential. This motivates the denomination of 'elastic' Coulomb gas. Such elastic Coulomb gases arise naturally in the study of the continuous melting transition of two-dimensional solids coupled to a substrate, either commensurate or with quenched disorder.

Carpentier, David [Laboratoire de Physique de l' Ecole Normale Superieure de Lyon-CNRS, 46, Allee d' Italie, 69364 Lyon Cedex 07 (France)], E-mail: david.carpentier@ens-lyon.fr; Le Doussal, Pierre [Laboratoire de Physique Theorique de l' Ecole Normale Superieure-CNRS, 24, Rue Lhomond 75005 Paris (France)

2008-06-01

191

Natural polymer-based magnetic hydrogels: Potential vectors for remote-controlled drug release.  

Science.gov (United States)

The preparation and characterization of natural polymer-based hydrogels that contain 50-nm diameter magnetite (i.e., FeO:Fe(2)O(3)) nanoparticles are described herein. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the efficiency of the polysaccharide-modifying process. Thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and compressive moduli demostrate that the presence of magnetite improves thermal and mechanical resistance. Transient diffusion of water in magnetic hydrogels was analyzed via boundary layer mass transfer across an expaning interface, and the degree of swelling of these polysaccharide hydrogels decreases in the presence of magnetite, with no variation in the binary diffusion mechanism. The absence of hysteresis loops and coercivity observed via magnetometry suggests that magnetic hydrogels are useful for remote-controlled drug release, as demonstrated by magnetic-field-induced release of curcumin. Experiments reveal that magnetic hydrogels with greater magnetic susceptibility have the potential to release larger concentrations of drugs from the hydrogel network. PMID:22939334

Paulino, Alexandre T; Pereira, Antonio G B; Fajardo, André R; Erickson, Kristin; Kipper, Matt J; Muniz, Edvani C; Belfiore, Laurence A; Tambourgi, Elias B

2012-10-15

192

Acanthamoeba polyphaga, a potential environmental vector for the transmission of food-borne and opportunistic pathogens.  

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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

193

Wild deer as potential vectors of anthelmintic-resistant abomasal nematodes between cattle and sheep farms.  

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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 components analysis of abomasal nematode species composition revealed differences between wild roe deer grazing in the areas of intensive livestock farming, and fallow and red deer in all environments. Alleles for benzimidazole (BZ) resistance were identified in ?-tubulin of Haemonchus contortus of roe deer and phenotypic resistance confirmed in vitro by an egg hatch test (EC50 = 0.149 µg ml(-1) ± 0.13 µg ml(-1)) on H. contortus eggs from experimentally infected sheep. This BZ-resistant H. contortus isolate also infected a calf experimentally. We present the first account of in vitro BZ resistance in wild roe deer, but further experiments should firmly establish the presence of phenotypic BZ resistance in vivo. Comprehensive in-field studies should assess whether nematode cross-transmission between deer and livestock occurs and contributes, in any way, to the development of resistance on livestock farms. PMID:24552838

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

2014-04-01

194

Scalar-vector-pseudoscalar Cornell potential for a spin-1/2 particle under spin and pseudospin symmetries: 1+1 dimensions  

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The Cornell potential consists of Coulomb and linear potentials, i.e. -a/x+bx, that has received a great deal of attention in particle and nuclear physics. In this paper, we present exact solutions of the Dirac equation with the mixed scalar-vector-pseudoscalar Cornell potential under spin and pseudospin symmetry limits. The corresponding eigenfunctions are given in the form of the biconfluent Heun polynomials.

Hamzavi, M.; Rajabi, A. A.

2013-07-01

195

Dos nuevos registros de vectores potenciales de Fiebre Amarilla selvática y Mayaro para el Ecuador / Two new records of potential Sylvan Yellow Fever and Mayaro species vectors from Ecuador  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish 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.

196

Approximate solution of the spin-one Duffin—Kemmer—Petiau (DKP) equation under a non-minimal vector Yukawa potential in (1+1)-dimensions  

International Nuclear Information System (INIS)

We solve the Duffin—Kemmer—Petiau (DKP) equation with a non-minimal vector Yukawa potential in (1+1)-dimensional space-time for spin-1 particles. The Nikiforov—Uvarov method is used in the calculations, and the eigenfunctions as well as the energy eigenvalues are obtained in a proper Pekeris-type approximation. (general)

197

Approximate solution of the spin-one Duffin—Kemmer—Petiau (DKP) equation under a non-minimal vector Yukawa potential in (1+1)-dimensions  

Science.gov (United States)

We solve the Duffin—Kemmer—Petiau (DKP) equation with a non-minimal vector Yukawa potential in (1+1)-dimensional space-time for spin-1 particles. The Nikiforov—Uvarov method is used in the calculations, and the eigenfunctions as well as the energy eigenvalues are obtained in a proper Pekeris-type approximation.

Hassanabadi, H.; Molaee, Z.

2012-12-01

198

Genetic diversity and potential vectors and reservoirs of Cucurbit aphid-borne yellows virus in southeastern Spain.  

Science.gov (United States)

The genetic variability of a Cucurbit aphid-borne yellows virus (CABYV) (genus Polerovirus, family Luteoviridae) population was evaluated by determining the nucleotide sequences of two genomic regions of CABYV isolates collected in open-field melon and squash crops during three consecutive years in Murcia (southeastern Spain). A phylogenetic analysis showed the existence of two major clades. The sequences did not cluster according to host, year, or locality of collection, and nucleotide similarities among isolates were 97 to 100 and 94 to 97% within and between clades, respectively. The ratio of nonsynonymous to synonymous nucleotide substitutions reflected that all open reading frames have been under purifying selection. Estimates of the population's genetic diversity were of the same magnitude as those previously reported for other plant virus populations sampled at larger spatial and temporal scales, suggesting either the presence of CABYV in the surveyed area long before it was first described, multiple introductions, or a particularly rapid diversification. We also determined the full-length sequences of three isolates, identifying the occurrence and location of recombination events along the CABYV genome. Furthermore, our field surveys indicated that Aphis gossypii was the major vector species of CABYV and the most abundant aphid species colonizing melon fields in the Murcia (Spain) region. Our surveys also suggested the importance of the weed species Ecballium elaterium as an alternative host and potential virus reservoir. PMID:23802870

Kassem, Mona A; Juarez, Miguel; Gómez, Pedro; Mengual, Carmen M; Sempere, Raquel N; Plaza, María; Elena, Santiago F; Moreno, Aranzazu; Fereres, Alberto; Aranda, Miguel A

2013-11-01

199

Synthesis of Mannosylated Polyethylenimine and Its Potential Application as Cell-Targeting Non-Viral Vector for Gene Therapy  

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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

200

Triatoma maculata, the Vector of Trypanosoma cruzi, in Venezuela. Phenotypic and Genotypic Variability as Potential Indicator of Vector Displacement into the Domestic Habitat.  

Science.gov (United States)

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

 
 
 
 
201

Triatoma maculata, the Vector of Trypanosoma cruzi, in Venezuela. Phenotypic and Genotypic Variability as Potential Indicator of Vector Displacement into the Domestic Habitat  

Science.gov (United States)

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

Garcia-Alzate, Roberto; Lozano-Arias, Daisy; Reyes-Lugo, Rafael Matias; Morocoima, Antonio; Herrera, Leidi; Mendoza-Leon, Alexis

2014-01-01

202

Transcriptome analysis of an mvp mutant reveals important changes in global gene expression and a role for methyl jasmonate in vernalization and flowering in wheat.  

Science.gov (United States)

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

203

Evaluation of linear heat rates for the power-to-melt tests on 'JOYO' using the Monte-Carlo code 'MVP'  

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)

204

Environmental risk assessment of replication competent viral vectors applied in clinical trials: potential effects of inserted sequences.  

Science.gov (United States)

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

205

Imported Asian swamp eels (Synbranchidae: Monopterus) in North American live food markets: Potential vectors of non-native parasites  

Science.gov (United States)

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

206

Support vector regression correlates single-sweep evoked brain potentials to gastrointestinal symptoms in diabetes mellitus patients  

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

207

Investigating the Potential Range Expansion of the Vector Mosquito Aedes Aegypti in Mexico with NASA Earth Science Remote Sensing Results  

Science.gov (United States)

In tropical and sub ]tropical regions, the mosquito Aedes aegypti is the major vector for the virus causing dengue, a serious public health issue in these areas. Through ongoing NSF- and NASA-funded studies, field surveys of Aedes aegypti and an integrated modeling approach are being used to improve our understanding of the potential range of the mosquito to expand toward heavily populated high elevation areas such as Mexico City under various climate change and socio ]economic scenarios. This work serves three primary objectives: (1) Employ NASA remotely-sensed data to supplement the environmental monitoring and modeling component of the project. These data-- for example, surface temperature, precipitation, vegetation indices, soil moisture and elevation-- are critical for understanding the habitat necessary for mosquito survival and abundance; (2) Implement training sessions to instruct scientists and students from Mexico and the U.S. on how to use remote sensing and implement the NASA SERVIR Regional Visualization and Monitoring System; (3) Employ the SERVIR framework to optimize the dissemination of key project results in order to increase their societal relevance and benefits in developing climate adaptation strategies. Field surveys of larval, pupal and adult Aedes aegypti, as well as detailed physical and social household characteristics, were conducted in the summers of 2011and 2012 at geographic scales from the household to the community along a transect from sea level to 2400 m ASL. These data are being used in models to estimate Aedes aegypti habitat suitability. In 2011, Aedes aegypti were identified at an elevation of over 2150 m in Puebla, the highest elevation at which this species has been observed.

Crosson, W. L.; Estes, M. G.; Estes, S. M.; Hayden, M.; Monaghan, A. J.; Eisen, L.; Lozano-Fuentes, S.; Ochoa, C.; Tapia, B.; Welsh-Rodriquez, C. M.; Quattrochi, D.; MorenoMadrinan, M. J.

2012-01-01

208

Transduction of human NOD/SCID-repopulating cells with both lymphoid and myeloid potential by foamy virus vectors.  

Science.gov (United States)

The efficiency of gene transfer into human hematopoietic stem cells by oncoretroviral vectors is too low for effective gene therapy of most hematologic diseases. Retroviral vectors based on the nonpathogenic foamy viruses (FV) are an alternative gene-transfer system. In this study, human umbilical cord blood CD34(+) cells were transduced with FV vectors by a single 10-h exposure to vector stocks and then injected into sublethally irradiated nonobese diabetic-severe combined immunodeficiency (NOD/SCID) mice. At 5-7 weeks after transplantation, high transgene expression rates were observed in engrafted human hematopoietic cells, including over 60% of clonogenic progenitors. Significant transgene silencing did not occur. We developed an approach for expanding human cell populations derived from transplanted mice to show that multiple SCID repopulating cells (SRCs) had been transduced, including some that were capable of both lymphoid and myeloid differentiation. These findings demonstrate for the first time that human pluripotent (lympho-myeloid) hematopoietic stem cells repopulate NOD/SCID mice and can be efficiently transduced by FV vectors. PMID:12060773

Josephson, Neil C; Vassilopoulos, George; Trobridge, Grant D; Priestley, Greg V; Wood, Brent L; Papayannopoulou, Thalia; Russell, David W

2002-06-11

209

Linking land cover and species distribution models to project potential ranges of malaria vectors: an example using Anopheles arabiensis in Sudan and Upper Egypt  

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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

210

Análisis costo-beneficio del control de vectores en la transmisión potencial de dengue / Cost-benefit analysis of vector control in areas of potential dengue transmission  

Scientific Electronic Library Online (English)

Full Text Available SciELO Public Health | Language: Spanish Abstract in spanish 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

211

Análisis costo-beneficio del control de vectores en la transmisión potencial de dengue Cost-benefit analysis of vector control in areas of potential dengue transmission  

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

212

Relativistic Coulomb excitation of the giant dipole resonance in nuclei: How to calculate transition probabilities without invoking the Lienard-Wiechert relativistic scalar and vector potentials  

International Nuclear Information System (INIS)

The conclusions extracted from a recent study of the excitation of giant dipole resonances in nuclei at relativistic bombarding energies open the way for a further simplification of the problem. It consists in the elimination of the relativistic scalar and vector electromagnetic potentials and the familiar numerical difficulties associated with their presence in the calculation scheme. The inherent advantage of a reformulation of the problem of relativistic Coulomb excitation of giant dipole resonances along these lines is discussed

213

The potential of QuikSCAT and WindSat observations for the estimation of sea surface wind vector under severe weather conditions - art. no. C09023  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The physics of remote sensing sea surface measurements is still poorly understood under severe weather conditions. Wind vector algorithms are usually developed for non-precipitating atmospheres and for wind speeds less than 20 m/s. In this study, we analyze observations from the QuikSCAT Ku-band scatterometer collocated with the WindSat full polarimetric microwave radiometer to estimate the potential of these two instruments for sea surface wind retrieval under severe weather conditions. The ...

Quilfen, Yves; Prigent, C.; Chapron, Bertrand; Mouche, Alexis; Houti, N.

2007-01-01

214

The potential of classic and specific bioelectrical impedance vector analysis for the assessment of sarcopenia and sarcopenic obesity  

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Full Text Available Elisabetta Marini,1 Roberto Buffa,1 Bruno Saragat,1 Alessandra Coin,2 Elena Debora Toffanello,2 Linda Berton,2 Enzo Manzato,2 Giuseppe Sergi21Department of Environmental and Life Sciences, University of Cagliari, Italy; 2Department of Medicine-DIMED, Geriatrics Section, University of Padua, ItalyPurpose: The aim of this paper is to investigate whether bioelectrical impedance vector analysis (BIVA can be a suitable technique for the assessment of sarcopenia. We also investigate the potential use of specific BIVA as an indicator of sarcopenic obesity.Subjects and methods: The sample comprised 207 free-living elderly individuals of both sexes, aged 65 to 93 years. Anthropometric and bioelectrical measurements were taken according to standard criteria. The “classic” and “specific” BIVA procedures, which respectively correct bioelectrical values for body height and body geometry, were used. Dual energy X-ray absorptiometry (DXA was used as the reference method for identifying sarcopenic and obese sarcopenic individuals. Bioelectrical and DXA values were compared using Student’s t-test and Hotelling’s T2 test, as well as Pearson’s correlation coefficient.Results: According to classic BIVA, sarcopenic individuals of both sexes showed higher values of resistance/height (R/H; p < 0.01 and impedance/height (Z/H; p < 0.01, and a lower phase angle (p < 0.01. Similarly, specific BIVA showed significant differences between sarcopenic and nonsarcopenic individuals (men: T2 = 15.7, p < 0.01; women: T2 = 10.7, p < 0.01, with the sarcopenic groups showing a lower specific reactance and phase angle. Phase angle was positively correlated with the skeletal muscle mass index (men: r = 0.52, p < 0.01; women: r = 0.31, p < 0.01. Specific BIVA also recognized bioelectrical differences between sarcopenic and sarcopenic obese men (T2 = 13.4, p < 0.01, mainly due to the higher values of specific R in sarcopenic obese individuals.Conclusion: BIVA detected muscle-mass variations in sarcopenic individuals, and specific BIVA was able to discriminate sarcopenic individuals from sarcopenic obese individuals. These procedures are promising tools for screening for presarcopenia, sarcopenia, and sarcopenic obesity in routine practice.Keywords: aging, body composition, BIVA, DXA

Marini E

2012-12-01

215

Lentiviral vector-mediated stable expression of sTNFR-Fc in human macrophage and neuronal cells as a potential therapy for neuroAIDS  

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Full Text Available Abstract Background Human immunodeficiency virus type 1 (HIV-1 infection frequently causes neurologic disease, which is the result of viral replication and activation of macrophages and microglia in the CNS, and subsequent secretion of high levels of neurotoxic products, including tumor necrosis factor-? (TNF-?. We therefore hypothesized that a soluble TNF-? antagonist might have potential utility as a neuroprotective effecter molecule, and conducted proof-of-concept studies to test this hypothesis. Methods To develop novel therapeutics for the treatment of neuroAIDS, we constructed and characterized a soluble TNF receptor (sTNFR-Fc fusion protein with the goal of neutralizing TNF-?, and tested the stability of expression of this gene following delivery by a lentiviral vector. Results High-titer lentiviral vectors were prepared, allowing efficient transduction of macrophage/glial and neuronal cell lines, as well as primary rat cerebellar neurons. Efficient, stable secretion of sTNFR-Fc was demonstrated in supernatants from transduced cell lines over 20 passages, using both western blot and ELISA. Biological activity of the secreted sTNFR-Fc was confirmed by TNF-specific in vitro protein binding and functional blocking assays. Finally, the secreted protein was shown to protect neuronal cells from TNF-?, HIV-1 Tat-, and gp120-mediated neurotoxicity. Conclusions These results demonstrate that lentiviral vector mediated expression of sTNFR-Fc may have potential as a novel therapy for neuroAIDS.

Maggirwar Sanjay B

2011-05-01

216

Beyond platinum: synthesis, characterization, and in vitro toxicity of Cu(II-releasing polymer nanoparticles for potential use as a drug delivery vector  

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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

217

Biology and population dynamics of the potential sugarcane Fiji disease vector Perkinsiella saccharicida (Homoptera: Delphacidae) in Réunion: evidence of its loss of biotic potential  

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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

218

The first dairy product exclusively fermented by Propionibacterium freudenreichii: a new vector to study probiotic potentialities in vivo.  

Science.gov (United States)

Dairy propionibacteria display probiotic properties which require high populations of live and metabolically active propionibacteria in the colon. In this context, the probiotic vector determines probiotic efficiency. Fermented dairy products protect propionibacteria against digestive stresses and generally contain a complex mixture of lactic and propionic acid bacteria. This does not allow the identification of dairy propionibacteria specific beneficial effects. The aim of this study was to develop a dairy product exclusively fermented by dairy propionibacteria. As they grow poorly in milk, we determined their nutritional requirements concerning carbon and nitrogen by supplementing milk ultrafiltrate (UF) with different concentrations of lactate and casein hydrolysate. Milk or UF supplemented with 50 mM lactate and 5 g L(-1) casein hydrolysate allowed growth of all dairy propionibacteria studied. In these new fermented dairy products, dairy propionibacteria remained viable and stress-tolerant in vitro during minimum 15 days at 4 °C. The efficiency of milk fermented by the most tolerant Propionibacterium freudenreichii strain was evaluated in piglets. Viability and SCFA content in the colon evidenced survival and metabolic activity of P. freudenreichii. This work results in the design of a new food grade vector, which will allow preclinical and clinical trials. PMID:22850385

Cousin, Fabien J; Louesdon, Séverine; Maillard, Marie-Bernadette; Parayre, Sandrine; Falentin, Hélène; Deutsch, Stéphanie-Marie; Boudry, Gaëlle; Jan, Gwénaël

2012-10-01

219

Generalization of the Second Order Vector Potential Formulation for Arbitrary Non-Orthogonal Curvilinear Coordinates Systems from the Covariant Form of Maxwell's Equations  

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Full Text Available A great number of semi-analytical models, notably the representation of electromagnetic fields by integral equations are based on the second order vector potential (SOVP formalism which introduces two scalar potentials in order to obtain analytical expressions of the electromagnetic fields from the two potentials. However, the scalar decomposition is often known for canonical coordinate systems. This paper aims in introducing a specific SOVP formulation dedicated to arbitrary non-orthogonal curvilinear coordinates systems. The electromagnetic field representation which is derived in this paper constitutes the key stone for the development of semi-analytical models for solving some eddy currents moelling problems and electromagnetic radiation problems considering at least two homogeneous media separated by a rough interface. This SOVP formulation is derived from the tensor formalism and Maxwell’s equations written in a non-orthogonal coordinates system adapted to a surface characterized by a 2D arbitrary aperiodic profile.

Denis Prémel

2012-10-01

220

$SU(1,1)$ coherent states for Dirac-Kepler-Coulomb problem in $D+1$ dimensions with scalar and vector potentials  

CERN Document Server

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

 
 
 
 
221

Vector and Spinor Decomposition of SU(2) Gauge Potential, Their Equivalence, and Knot Structure in SU(2) Chern-Simons Theory  

International Nuclear Information System (INIS)

In this paper, spinor and vector decompositions of SU(2) gauge potential are presented and their equivalence is constructed using a simply proposal. We also obtain the action of Faddeev nonlinear O(3) sigma model from the SU(2) massive gauge field theory, which is proposed according to the gauge invariant principle. At last, the knot structure in SU(2) Chern-Simons filed theory is discussed in terms of the ?-mapping topological current theory. The topological charge of the knot is characterized by the Hopf indices and the Brouwer degrees of ?-mapping.

222

SU(1,1) coherent states for Dirac-Kepler-Coulomb problem in D+1 dimensions with scalar and vector potentials  

Science.gov (United States)

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-Guillén, D.; Mota, R. D.; Granados, V. D.

2014-08-01

223

Predictive screening model for potential vector-mediated transport of cationic substrates at the blood-brain barrier choline transporter.  

Science.gov (United States)

A set of semi-rigid cyclic and acyclic bis-quaternary ammonium analogs, which were part of a drug discovery program aimed at identifying antagonists at neuronal nicotinic acetylcholine receptors, were investigated to determine structural requirements for affinity at the blood-brain barrier choline transporter (BBB CHT). This transporter may have utility as a drug delivery vector for cationic molecules to access the central nervous system. In the current study, a virtual screening model was developed to aid in rational drug design/ADME of cationic nicotinic antagonists as BBB CHT ligands. Four 3D-QSAR comparative molecular field analysis (CoMFA) models were built which could predict the BBB CHT affinity for a test set with an r(2) libraries with the goal of informing the design of brain bioavailable quaternary ammonium analogs that are high affinity selective nicotinic receptor antagonists. PMID:20053562

Geldenhuys, Werner J; Manda, Vamshi K; Mittapalli, Rajendar K; Van der Schyf, Cornelis J; Crooks, Peter A; Dwoskin, Linda P; Allen, David D; Lockman, Paul R

2010-02-01

224

Genetic characterization and molecular identification of the bloodmeal sources of the potential bluetongue vector Culicoides obsoletus in the Canary Islands, Spain  

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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

225

Cuticular and internal chemical composition of biting midges Culicoides spp. (Diptera: Ceratopogonidae), potential vectors of viral diseases.  

Science.gov (United States)

The chemical profile of the cuticle and internal tissues of four species of Culicoides have been studied for the first time by gas chromatography-mass spectrometry. The chemical composition of females of C. obsoletus s.l. and C. lupicaris, vectors of diverse viral diseases, have been compared with that of other biting midges, such as C. kibunensis and C. fascipennis, and the non-biting midge Forcipomyia bipunctata. A total of 61 compounds belonging to 8 major chemical classes were identified in cuticular and internal tissues in n-hexane extracts. The compounds include carboxylic acids (CAs) (C6-C20), with C16:0, C16:1 and C18:1 being dominant, branched hydrocarbons (C29 to C38 mono/di/trimethylalkanes), linear hydrocarbons (C15 to C33, mainly odd chain carbons), terpenes (geranylacetone, geranylgeraniol acetate, squalene, terpenic alcohol), steroids (cholesterol), aldehydes (C9-C10 and even chain C20 to C30), and esters. The chemical profile depends on the species and whether the extracts are external (cuticle) or internal. The contents of linear and branched hydrocarbons and aldehydes was high in cuticular extracts but practically absent in internal tissues, which were, in contrast, rich in CAs, terpenes and steroids. The results are discussed and compared with other Culicoides midges and mosquito-related species. PMID:25233583

González, Mikel; López, Sergio; Rosell, Gloria; Goldarazen, Arturo; Guerrero, Angel

2014-08-01

226

Radiosensitization of gliomas by intracellular generation of 5-fluorouracil potentiates prodrug activator gene therapy with a retroviral replicating vector.  

Science.gov (United States)

A tumor-selective non-lytic retroviral replicating vector (RRV), Toca 511, and an extended-release formulation of 5-fluorocytosine (5-FC), Toca FC, are currently being evaluated in clinical trials in patients with recurrent high-grade glioma (NCT01156584, NCT01470794 and NCT01985256). Tumor-selective propagation of this RRV enables highly efficient transduction of glioma cells with cytosine deaminase (CD), which serves as a prodrug activator for conversion of the anti-fungal prodrug 5-FC to the anti-cancer drug 5-fluorouracil (5-FU) directly within the infected cells. We investigated whether, in addition to its direct cytotoxic effects, 5-FU generated intracellularly by RRV-mediated CD/5-FC prodrug activator gene therapy could also act as a radiosensitizing agent. Efficient transduction by RRV and expression of CD were confirmed in the highly aggressive, radioresistant human glioblastoma cell line U87EGFRvIII and its parental cell line U87MG (U87). RRV-transduced cells showed significant radiosensitization even after transient exposure to 5-FC. This was confirmed both in vitro by a clonogenic colony survival assay and in vivo by bioluminescence imaging analysis. These results provide a convincing rationale for development of tumor-targeted radiosensitization strategies utilizing the tumor-selective replicative capability of RRV, and incorporation of radiation therapy into future clinical trials evaluating Toca 511 and Toca FC in brain tumor patients. PMID:25301172

Takahashi, M; Valdes, G; Hiraoka, K; Inagaki, A; Kamijima, S; Micewicz, E; Gruber, H E; Robbins, J M; Jolly, D J; McBride, W H; Iwamoto, K S; Kasahara, N

2014-10-01

227

Laboratory studies of a Brazilian strain of Aedes albopictus as a potential vector of Mayaro and Oropouche viruses.  

Science.gov (United States)

The vector efficiency of colonized Aedes albopictus from Brazil was assessed for Mayaro (MAY) and Oropouche (ORO) viruses. Female mosquitoes, 3-4 days old, were fed on a MAY-infected hamster with a viremia level of 5.3 log10 Vero cell plaque-forming units (PFU) of virus/ml or an ORO-infected hamster circulating 7.3 log10 PFU/ml. Mayaro infection rates among fed mosquitoes were 16.9 and 11% at 6, 13 and 20 days postfeeding, respectively, and 1/2 and 2/2 infected mosquitoes transmitted virus on days 13 and 20, respectively. Only 13, 5 and 3% of mosquitoes were infected with ORO virus at 6, 13 and 20 days, respectively, and no transmission occurred. Mosquitoes were also fed on 3 dilutions of MAY virus-blood suspensions in membrane feeders. The infection rate among mosquitoes fed the highest concentration (7.7 log10 PFU/ml) was 11/13 (85%), and 5/11 (46%) infected mosquitoes transmitted virus. PMID:1646286

Smith, G C; Francy, D B

1991-03-01

228

Seasonal dynamics of Culicoides (Diptera: Ceratopogonidae) biting midges, potential vectors of African horse sickness and bluetongue viruses in the Niayes area of Senegal  

Science.gov (United States)

Background The African horse sickness epizootic in Senegal in 2007 caused considerable mortality in the equine population and hence major economic losses. The vectors involved in the transmission of this arbovirus have never been studied specifically in Senegal. This first study of the spatial and temporal dynamics of the Culicoides (Diptera: Ceratopogonidae) species, potential vectors of African horse sickness in Senegal, was conducted at five sites (Mbao, Parc Hann, Niague, Pout and Thies) in the Niayes area, which was affected by the outbreak. Methods Two Onderstepoort light traps were used at each site for three nights of consecutive collection per month over one year to measure the apparent abundance of the Culicoides midges. Results In total, 224,665 specimens belonging to at least 24 different species (distributed among 11 groups of species) of the Culicoides genus were captured in 354 individual collections. Culicoides oxystoma, Culicoides kingi, Culicoides imicola, Culicoides enderleini and Culicoides nivosus were the most abundant and most frequent species at the collection sites. Peaks of abundance coincide with the rainy season in September and October. Conclusions In addition to C. imicola, considered a major vector for the African horse sickness virus, C. oxystoma may also be involved in the transmission of this virus in Senegal given its abundance in the vicinity of horses and its suspected competence for other arboviruses including bluetongue virus. This study depicted a site-dependent spatial variability in the dynamics of the populations of the five major species in relation to the eco-climatic conditions at each site. PMID:24690198

2014-01-01

229

Mapping of zones potentially occupied by Aedes vexans and Culex poicilipes mosquitoes, the main vectors of Rift Valley fever in Senegal.  

Science.gov (United States)

A necessary condition for Rift Valley fever (RVF) emergence is the presence of Aedes (Aedimorphus) vexans and Culex (Culex) poicilipes mosquitoes carrying the arbovirus and responsible for the infection. This paper presents a detailed mapping in the Sahelian region of Senegal of zones potentially occupied by these mosquitoes (ZPOMs) whose population density is directly linked to ecozones in the vicinity of small ponds. The vectors habitats and breeding sites have been characterized through an integrated approach combining remote sensing technology, geographical information systems, geographical positioning systems and field observations for proper geo-referencing. From five SPOT-5 images (approximately 10 m spatial resolution) with appropriate channels, a meridional composite transect of 290 x 60 km was first constructed at the height of the summer monsoon. Subsequent ZPOMs covered major ecozones from north to south with different hydrological environments and different patterns pond distributions. It was found that an overall area of 12,817 ha +/- 10% (about 0.8% of the transect) is occupied by ponds with an average ZPOM 17 times larger than this (212,813 ha +/- 10% or about 14% of the transect). By comparing the very humid year of 2003 with 2006 which had just below normal rainfall, the ZPOMs inter-annual variability was analyzed in a sandy-clayey ecozone with an important hydrofossil riverbed within the Ferlo region of Senegal. Very probably contributing to an increased abundance of vectors by the end of August 2003, it was shown that the aggregate pond area was already about 22 times larger than in August 2006, corresponding to an approximately five times larger total ZPOM. The results show the importance of pin-pointing small ponds (sizes down to 0.1 ha) and their geographical distribution in order to assess animal exposure to the RVF vectors. PMID:19021110

Tourre, Yves M; Lacaux, Jean-Pierre; Vignolles, Cecile; Ndione, Jacques-André; Lafaye, Murielle

2008-11-01

230

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

231

Potential of contact insecticides to control Xyleborus glabratus (Coleoptera: Curculionidae), a vector of laurel wilt disease in avocados.  

Science.gov (United States)

Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae) is an invasive ambrosia beetle that vectors laurel wilt, a new disease that threatens avocado and other species in the Lauraceae Family. The lethal concentrations (LC50 & 90) of nine commercial insecticides to X. glabratus were determined by using a bolt-dip bioassay. Different formulations of bifenthrin, permethrin, fenpropathrin, z-cypermethrin + bifenthrin, 1-cyhalothrin + thiamethoxam, malathion, chlorpyrifos, carbaryl, and methomyl were tested. Four concentrations of each insecticide were tested (0.5, 0.1, 0.03, and 0.01 of the label rate) and with water as a control. Beetles were exposed to treated bolts and mortality registered 48 h later. After 2 wk, bolts were destructively sampled to determine the number of beetles that constructed galleries and were alive inside the wood. Probit analysis was used to determine the LC50 & 90. Six pesticides were applied directly to the trunk and limbs of avocado trees in a commercial grove. Limbs of treated trees were cut weekly after the application and exposed to X. glabratus to determine the number of beetles boring into the logs. The toxicity of pesticides to X. glabratus was greatly reduced 2 wk after application. Among the tested pesticides, malathion and z-cypermethrin + bifenthrin provided the best suppression of X. glabratus. Among the insecticides registered for use in avocado, fenpropathrin and malathion were the most effective in protecting trees from attack by X. glabratus. Other pesticides that are currently not registered for use in avocados could be useful for managing this ambrosia beetle. PMID:24498726

Carrillo, Daniel; Crane, Jonathan H; Peña, Jorge E

2013-12-01

232

The enzyme 3-hydroxykynurenine transaminase as potential target for 1,2,4-oxadiazoles with larvicide activity against the dengue vector Aedes aegypti.  

Science.gov (United States)

The mosquito Aedes aegypti is the vector agent responsible for the transmission of yellow fever and dengue fever viruses to over 80 million people in tropical and subtropical regions of the world. Exhaustive efforts have lead to a vaccine candidate with only 30% effectiveness against the dengue virus and failure to protect patients against the serotype 2. Hence, vector control remains the most viable route to dengue fever control programs. We have synthesized a class of 1,2,4-oxadiazole derivatives whose most biologically active compounds exhibit potent activity against Aedes aegypti larvae (ca. of 15 ppm) and low toxicity in mammals. Exposure to these larvicides results in larvae pigmentation in a manner correlated with the LC50 measurements. Structural comparisons of the 1,2,4-oxadiazole nucleus against known inhibitors of insect enzymes allowed the identification of 3-hydroxykynurenine transaminase as a potential target for these synthetic larvicides. Molecular docking calculations indicate that 1,2,4-oxadiazole compounds can bind to 3-hydroxykynurenine transaminase with similar conformation and binding energies as its crystallographic inhibitor 4-(2-aminophenyl)-4-oxobutanoic acid. PMID:24095017

Oliveira, Vanessa S; Pimenteira, Cecília; da Silva-Alves, Diana C B; Leal, Laylla L L; Neves-Filho, Ricardo A W; Navarro, Daniela M A F; Santos, Geanne K N; Dutra, Kamilla A; dos Anjos, Janaína V; Soares, Thereza A

2013-11-15

233

Which potential. A comparison of the various scalar and vector potentials for the numerical solution of the non-linear poisson problem  

International Nuclear Information System (INIS)

This paper summarises the formulation and results of a study aimed at deciding which potential definition to select for constructing a set of computer algorithms for the non-linear Poissonian field problem. The two dimensional Magnetostatic case is used in this investigation and solutions are presented for shielding and motor problems. Of the four potentials considered the choice of a double scalar potential appears to offer the most attractive formulation for extension to three dimensions. The report contains results for the first part of an on-going study which is ultimately to develop an efficient full three dimensional non-linear field computer program. (author)

234

Three dimensional magnetic fields in extra high speed modified Lundell alternators computed by a combined vector-scalar magnetic potential finite element method  

Science.gov (United States)

A 3D finite element (FE) approach was developed and implemented for computation of global magnetic fields in a 14.3 kVA modified Lundell alternator. The essence of the new method is the combined use of magnetic vector and scalar potential formulations in 3D FEs. This approach makes it practical, using state of the art supercomputer resources, to globally analyze magnetic fields and operating performances of rotating machines which have truly 3D magnetic flux patterns. The 3D FE-computed fields and machine inductances as well as various machine performance simulations of the 14.3 kVA machine are presented in this paper and its two companion papers.

Demerdash, N. A.; Wang, R.; Secunde, R.

1992-01-01

235

Weedy hosts and prevalence of potential leafhopper vectors (Hemiptera: Cicadellidae) of a phytoplasma (16SrIX group) associated with Huanglongbing symptoms in citrus groves.  

Science.gov (United States)

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

236

A Potential Role for Ixodid (Hard) Tick Vectors in the Transmission of Lumpy Skin Disease Virus in Cattle.  

Science.gov (United States)

Lumpy skin disease (LSD) is an economically important cattle disease. The disease is endemic in many African countries, but outbreaks have also been reported in Madagascar and the Middle East. The aim of this study was to investigate the potential role of ixodid (hard) ticks in the transmission of the disease. Cattle were infected with a virulent, South African field isolate of lumpy skin disease virus (LSDV). Three common African tick species (genera Rhipicephalus, Amblyomma and Rhipicephalus (Boophilus)) in different life cycle stages were fed on the infected animals during the viraemic stage and on skin lesions. Post-feeding, the partially fed male ticks were transferred to the skin of non-infected 'recipient' animals, while females were allowed to lay eggs that were then tested using the polymerase chain reaction (PCR) method and virus isolation. Nymphs were allowed to develop for 2-3?weeks after which time they were tested. The non-infected 'recipient' cattle were closely monitored, both skin and blood samples were tested using PCR and virus isolation, and serum samples were tested by the serum neutralization test. This is the first report showing molecular evidence of potential transmission of LSDV by ixodid ticks. The study showed evidence of transstadial and transovarial transmission of LSDV by R. (B.) decoloratus ticks and mechanical or intrastadial transmission by R. appendiculatus and A. hebraeum ticks. PMID:21114790

Tuppurainen, E S M; Stoltsz, W H; Troskie, M; Wallace, D B; Oura, C A L; Mellor, P S; Coetzer, J A W; Venter, E H

2010-11-30

237

Cloning vector  

Science.gov (United States)

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

238

Studies on the occurrence of Gram-negative bacteria in ticks: Ixodes ricinus as a potential vector of Pasteurella.  

Science.gov (United States)

A total of 372 Ixodes ricinus ticks (101 females, 122 males, and 149 nymphs) collected by flagging in 6 mixed woodlands of eastern Poland were examined by culture for the presence of internal Gram-negative bacteria other than Borrelia burgdorferi. Adult ticks were examined in pools of 2 specimens each and nymphs were examined in pools of 3-5 specimens each. Ticks were disinfected in 70 % ethanol and homogenized in 0.85% NaCl. The diluted homogenate was inoculated onto 3 kinds of agar media: buffered charcoal yeast extract (BCYE-alpha) for isolation of fastidious Gram-negative bacteria, eosin methylene blue agar (EMB) for isolation of enterobacteria, and tryptic soya agar for isolation of all other non-fastidious Gram-negative bacteria. The Gram-negative isolates were identified with the API Systems 20E and NE microtests. A total of 9 species of Gram-negative bacteria were identified, of which the commonest were strains determined as Pasteurella pneumotropica/haemolytica, which were isolated on BCYE-alpha agar from ticks collected in all 6 examined woodlands. The total number of these strains (49) exceeded the total number of all other strains of Gram-negative bacteria recovered from ticks (30). Of the total number of examined ticks, the minimum infection rate with Pasteurella pneumotropica/haemolytica was highest in females (18.8%), and slightly lower in males (12.3%) and nymphs (10%). Besides Pasteurella pneumotropica/haemolytica, the following species of Gram-negative bacteria were isolated from examined ticks: Pantoea agglomerans, Serratia marcescens, Serratia plymuthica on EMB agar and Aeromonas hydrophila, Burkholderia cepacia, Chromobacterium violaceum, Pseudomonas aeruginosa, and Stenotrophomonas maltophilia on tryptic soya agar. Minimal infection rates with these bacteria were low, ranging from 0.7-5.9%. Of the isolated bacteria, Chromobacterium violaceum, Pasteurella pneumotropica/haemolytica, Pseudomonas aeruginosa, and Serratia marcescens are potentially pathogenic for man and/or animals. In particular, the common occurrence of Pasteurella pneumotropica/haemolytica in Ixodes ricinus ticks poses a potential risk of pasteurellosis for humans and animals exposed to tick bites. PMID:15627343

Stojek, Nimfa Maria; Dutkiewicz, Jacek

2004-01-01

239

Vector inflation by kinetic coupled gravity  

Science.gov (United States)

Vector inflation is a newly established model where inflation is driven by nonminimally 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 model of vector inflation where the vector field has no potential term and is nonminimally coupled to gravity through the kinetic term. This model shows that vector inflation without a potential term is possible and helps to avoid the fine tuning problem in inflationary models having a potential. The nonminimal coupling is established by introducing the Einstein tensor besides the metric tensor within the kinetic term of the vector field. A perturbation analysis is performed to confront the inflation under discussion with Planck and BICEP2 results.

Darabi, F.; Parsiya, A.

2014-07-01

240

Vector financial rogue waves  

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.

 
 
 
 
241

Inhibition of vascular endothelial growth factor expression in keloid fibroblasts by vector-mediated vascular endothelial growth factor shRNA: a therapeutic potential strategy for keloid.  

Science.gov (United States)

Vascular endothelial growth factor (VEGF) plays important roles in the regulation of angiogenesis and inflammation in both pathological and physiological wound repair. Several strategies have been developed for keloid therapy; however, a universally effective treatment has not been explored to date. In this study, three potential short interfering RNA (siRNA) sequences for the VEGF gene were cloned into expression plasmids and transfected into keloid fibroblasts. PGC-VEGF shRNA 2 (short hairpin RNA 2) plasmid significantly inhibited VEGF expression determined by real-time polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and fibroblasts growth was also significantly by (methyl thiazolyl tetrazolium) MTT assay and apoptosis detection, whereas the control transfection showed no obviously effects. Plasminogen activator inhibitor-1 (PAI-1) expression in pGC-VEGF shRNA2 group was also obviously downregulated when compared to the pGC-VEGF shRNA negative control and mock group. These results suggest that modulation of VEGF production by vector-based RNAi in keloid fibroblasts may be a therapeutic potential strategy for keloid. PMID:18239926

Zhang, Guo-You; Yi, Cheng-Gang; Li, Xuan; Zheng, Yan; Niu, Zhan-Guo; Xia, Wei; Meng, Zhou; Meng, Cheng-Yue; Guo, Shu-Zhong

2008-04-01

242

Identification of potential stroke targets by lentiviral vector mediated overexpression of HIF-1 alpha and HIF-2 alpha in a primary neuronal model of hypoxia.  

Science.gov (United States)

The identification of genes differentially regulated by ischemia will lead to an improved understanding of cell death pathways such as those involved in the neuronal loss observed following a stroke. Furthermore, the characterization of such pathways could facilitate the identification of novel targets for stroke therapy. We have used a novel approach to amplify differential gene expression patterns in a primary neuronal model of stroke by employing a lentiviral vector system to specifically bias the transcriptional activation of hypoxically regulated genes. Overexpression of the hypoxia-induced transcription factor subunits HIF-1 alpha and HIF-2 alpha elevated hypoxia-mediated transcription of many known HIF-regulated genes well above control levels. Furthermore, many potentially novel HIF-regulated genes were discovered that were not previously identified as hypoxically regulated. Most of the novel genes identified were activated by a combination of HIF-2 alpha overexpression and hypoxic insult. These included several genes with particular importance in cell survival pathways and of potential therapeutic value. Hypoxic induction of HIF-2 alpha may therefore be a critical factor in mediating protective responses against ischemic injury. Further investigation of the genes identified in this study may provide increased understanding of the neuronal response to hypoxia and may uncover novel therapeutic targets for the treatment of cerebral ischemia. PMID:14747751

Ralph, G S; Parham, S; Lee, S R; Beard, G L; Craigon, M H; Ward, N; White, J R; Barber, R D; Rayner, W; Kingsman, S M; Mundy, C R; Mazarakis, N D; Krige, D

2004-02-01

243

Insecticide resistance and vector control.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

244

Ecological aspects of mosquitoes (Diptera: Culicidae) in the gallery forest of Brasilia National Park, Brazil, with an emphasis on potential vectors of yellow fever  

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

245

Vector financial rogue waves  

Science.gov (United States)

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.

Yan, Zhenya

2011-11-01

246

An efficient deletion mutant packaging system for defective herpes simplex virus vectors: Potential applications to human gene therapy and neuronal physiology  

Energy Technology Data Exchange (ETDEWEB)

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 {beta}-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 {beta}-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.

Geller, A.I.; Keyomarsi, K.; Bryan, J.; Pardee, A.B. (Dana-Farber Cancer Inst., Boston, MA (United States))

1990-11-01

247

An efficient deletion mutant packaging system for defective herpes simplex virus vectors: Potential applications to human gene therapy and neuronal physiology  

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

248

Comparative characterization and cytotoxicity study of TAT-peptide as potential vectors for siRNA and Dicer-substrate siRNA.  

Science.gov (United States)

Abstract Recently, a newly discovered Dicer-substrate siRNA (DsiRNA) demonstrates higher potency in gene silencing than siRNA but both suffer from rapid degradation, poor cellular uptake and chemical instability. Therefore, Tat-peptide was exploited to protect and facilitate their delivery into cells. In this study, Tat-peptide was complexed with siRNA or DsiRNA through simple complexation. The physicochemical properties (particle size, surface charge and morphology) of the complexes formed were then characterized. The ability of Tat-peptide to carry and protect siRNA or DsiRNA was determined by UV-Vis spectrophotometry and serum protection assay, respectively. Cytotoxicity effect of these complexes was assessed in V79 cell line. siRNA-Tat complexes had particle size ranged from 186?±?17.8 to 375?±?8.3?nm with surface charge ranged from -9.3?±?1.0 to +13.5?±?1.0?mV, depending on the Tat-to-siRNA concentration ratio. As for DsiRNA-Tat complexes, the particle size was smaller than the ones complexed with siRNA, ranging from 176?±?8.6 to 458?±?14.7?nm. Their surface charge was in the range of +27.1?±?3.6 to +38.1?±?0.9?mV. Both oligonucleotide (ON) species bound strongly to Tat-peptide, forming stable complexes with loading efficiency of more than 86%. These complexes were relatively non cytotoxic as the cell viability of ?90% was achieved. In conclusion, Tat-peptide has a great potential as siRNA and DsiRNA vector due to the formation of stable complexes with desirable physical characteristics, low toxicity and able to carry high amount of siRNA or DsiRNA. PMID:23962166

Katas, Haliza; Abdul Ghafoor Raja, Maria; Ee, Lee Choy

2014-11-01

249

Species composition, larval habitats, seasonal occurrence and distribution of potential malaria vectors and associated species of Anopheles (Diptera: Culicidae from the Republic of Korea  

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

250

Strong larvicidal potential of Artemisia annua leaf extract against malaria (Anopheles stephensi Liston) and dengue (Aedes aegypti L.) vectors and bioassay-driven isolation of the marker compounds.  

Science.gov (United States)

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

251

Energy dependence of EBT-1 radiochromic film response for photon (10 kVp-15 MVp) and electron beams (6-18 MeV) readout by a flatbed scanner  

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 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.

252

Mosquitoes (Diptera: Culiciadae potential vectors of arbovirus in the Urabá region, Northwest of Colombia Mosquitos (Díptera: Culicidae vectores potenciales de arbovirus en la región de Urabá, noroccidente de Colombia  

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Full Text Available Introduction. Studies directed to investigate ecological parameters of sylvatic mosquitoes populations allows to establish the risk of arbovirus transmission and to bring recommendations for health authorities about prevention, surveillance and control.
Objective. To establish the diversity and abundance of arbovirus mosquitoes vectors of in rural areas of Apartado and Turbo, Antioquia.
Materials and methods. Quarterly sampling was done. For mosquito catching in forest fragments, CDC and Shannon traps was used, also human landing was used. Diversity and abundance indexes estimation was done.
Results. 583 mosquitoes belonging to ten genera and 27 species were collected. The most abundant species were: Cq. venezuelensis (14.6%, Ae. scapularis (14.08%, Ps. ferox (10.82% and Cx quinquefasciatus (10.3%. Specific richness and ecological indexes were highest in Turbo municipality; the fragment studied in Turbo is considered of most species richness and uniformity. The finding of Cx pedroi, Ae. scapularis, Ae. angustivittatus, Cq. venezuelensis, Cx. nigripalpus, Cx. quinquefasciatus, Cx. declarator, Ma. titillans, Ma. pseudotitillans, Ps. ferox y Tr. digitatum previously reported as arbovirus vectors warns about the possibility of transmission in the zone.
Conclusions. Mosquito diversity and abundance in the study zone is high. The ecological analysis plus previous reports about vectorial capacity of some of the registered species allows us to conclude that arbovirus outbreaks in the area could be presented.
Introducción. Estudios encaminados a conocer parámetros ecológicos de poblaciones de mosquitos selváticos, permiten establecer el riesgo de transmisión de arbovirus y aportar recomendaciones sobre prevención, vigilancia y control a las autoridades de salud.
Objetivo. Determinar la diversidad y abundancia de mosquitos nocturnos y crepusculares, potenciales vectores de arbovirus en zonas rurales de Apartadó y Turbo, Antioquia.
Materiales y métodos. Se realizaron muestreos trimestrales. Para la recolecta de mosquitos se usaron trampas CDC, Shannon y cebo humano protegido, en fragmentos de bosque entre las 18:00 y 06:00 horas. Se estimaron índices de diversidad y abundancia de especies.
Resultados. Se capturaron 583 mosquitos, de 10 géneros y 27 especies. Las especies más abundantes fueron Cq. venezuelensis (14,6%, Ae. scapularis (14,08%, Ps. ferox (10,82% y Cx quinquefasciatus (10,3%. La riqueza específica y los índices ecológicos calculados fueron mayores en Turbo; el fragmento de bosque estudiado en Turbo se considera de mayor riqueza y uniformidad de especies. El hallazgo de Cx pedroi, Ae. scapularis, Ae. angustivittatus, Cq. venezuelensis, Cx. nigripalpus, Cx. quinquefasciatus, Cx. declarator, Ma. titillans, Ma. pseudotitillans, Ps. ferox y Tr. digitatum reportados como vectores de arbovirus alerta sobre la posibilidad de transmisión en la zona.
Conclusión. La diversidad y abundancia de mosquitos en la zona de estudio es alta. Los análisis ecológicos, mas los reportes previos de capacidad vectorial de algunas de las especies registradas, permiten concluir que en la zona se pueden presentar brotes de arbovirosis.

Laura Suárez

2011-12-01

253

Expression vectors for quantitating in vivo translational ambiguity: their potential use to analyse frameshifting at the HIV gag-pol junction.  

Science.gov (United States)

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

254

The Potential for Dispersal of Onchocerciasis in Ecuador in Relation to the Distribution of the Vector Simulium exiguum (Diptera:Simuliidae)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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.

255

Comparison of Potato and Asian Citrus Psyllid Adult and Nymph Transcriptomes Identified Vector Transcripts with Potential Involvement in Circulative, Propagative Liberibacter Transmission  

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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

256

Como o potencial vetor deve ser interpretado para revelar analogias entre grandezas magnéticas e elétricas / How the vector potential is to be interpreted in order to reveal analogies between magnetic and electric quantities  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Mostra-se a partir dos potenciais de Liénard-Wiechert que o potencial vetor pode, em geral, ser expresso como produto do potencial escalar e da velocidade da carga que o cria, constituindo-se como se fosse uma espécie de vento de potencial. Mostra-se daí como uma certa analogia existente entre grand [...] ezas magnéticas e elétricas pode ser entendida. Abstract in english Starting from the Liénard-Wiechert potentials, it is shown that the vector potential can always be expressed as a product of the scalar potential and the velocity of the charge creating it, looking like a kind of potential wind. From that, it is shown how a certain existing similarity between magnet [...] ic and electric quantities may be understood.

G.F. Leal, Ferreira.

2004-12-01

257

Present status of reactor physics in the United States and Japan-IV. 3. 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 (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

258

Chikungunya Virus–Vector Interactions  

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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

259

Vector-associated diseases in the context of climate change: Analysis and evaluation of the differences in the potential spread of tertian malaria in the ecoregions of Lower Saxony  

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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

260

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)

 
 
 
 
261

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

262

Guelph Physics Tutorials: Vectors  

Science.gov (United States)

This page offers a straightforward tutorial on the fundamentals of vector operations. It is an illustrated guide to vector subtraction/addition, vector resolution, and multiplication of two vectors. It could serve as textbook supplementation or as content support for science teachers.

2008-08-15

263

[Spatial vector electrocardiography: technique, perspectives of use].  

Science.gov (United States)

Potentials of the use of computer synthesis of integral electrical vector of the heart D0 are described. Calculation of spatial angular vector velocity and linear velocity of its movement along trajectory can be carried out in a framework of biophysical dipole model. Spatial presentation of vector is realized and its behavior in accordance with established pathologies discussed. Possible diagnostic value of obtained results and utility of their introduction into clinical practice are stressed. PMID:12891251

Bakutski?, V N; Volobuev, A N; Kriukov, N N; Romanchuk, P I

2003-01-01

264

Recombinant viral vectors: cancer vaccines.  

Science.gov (United States)

To date cancer vaccines have yet to show efficacy in a phase III trial. However, the clinical benefit seen with monoclonal antibody mediated therapies (e.g., Herceptin) has provided proof of principle that immune responses directed against tumour-associated antigens could have therapeutic potential. The failure of past cancer vaccine trials is likely due to several factors including the inappropriate choice of tumour antigen, use of an unoptimised antigen delivery system or vaccination schedule or selection of the wrong patient group. Any one of these variables could potentially result in the induction of an immune response of insufficient magnitude to deliver clinical benefit. Live recombinant viral vaccines have been used in the development of cancer immunotherapy approaches for the past 10 years. Though such vectors are self-adjuvanted and offer the ability to express multiple tumour-associated antigens (TAAs) along with an array of immune co-factors, arguably, they have yet to demonstrate convincing efficacy in pivotal clinical trials. However, in recent years, more coordinated studies have revealed mechanisms to optimise current vectors and have lead to the development of new advantageous vector systems. In this review, we highlight that live recombinant viral vectors provide a versatile and effective antigen delivery system and describe the optimal properties of an effective viral vector. Additionally, we discuss the advantages and disadvantages of the panel of recombinant viral systems currently available to cancer vaccinologists and how they can work in synergy in heterologous prime boost protocols and with other treatment modalities. PMID:17030074

Harrop, Richard; John, Justin; Carroll, Miles W

2006-10-01

265

Potential use of neem leaf slurry as a sustainable dry season management strategy to control the malaria vector Anopheles gambiae (DIPTERA: CULICIDAE) in west African villages.  

Science.gov (United States)

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

266

The use of annual killifish in the biocontrol of the aquatic stages of mosquitoes in temporary bodies of fresh water; a potential new tool in vector control  

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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

267

Caracteres moleculares para la determinación taxonómica de tres especies de Lutzomyia (Diptera: Psychodidae), vectores potenciales de Leishmania presentes en el valle de Aburrá, Colombia / Molecular characters for the taxonomic determination of three species of Lutzomyia (Diptera: Psychodidae), potential Leishmania vectors found in the Aburrá valley, Colombia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish 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.

268

Yersinia pestis insecticidal-like toxin complex (Tc family proteins: characterization of expression, subcellular localization, and potential role in infection of the flea vector  

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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

269

Larvicidal potential of wild mustard (Cleome viscosa) and gokhru (Tribulus terrestris) against mosquito vectors in the semi-arid region of Western Rajasthan.  

Science.gov (United States)

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

270

Larvicidal, Repellent, and Irritant Potential of the Seed-Derived Essential oil of Apium graveolens Against Dengue Vector, Aedes aegypti L. (Diptera: Culicidae)  

Science.gov (United States)

Aedes aegypti L. is one of the primary disease vectors spreading various dreadful diseases throughout the world, specifically over tropics and subtropics. Keeping in view the adverse effects of chemical insecticides-based intervention measures, the eco-friendly and bio-degradable essential oil extracted from the seeds of celery, Apium graveolens were investigated for its efficacy against Ae. aegypti. Larvicidal bioassay carried out with the seed oil against early fourth instars of Ae. aegypti caused an LC50 and LC90 values of 16.10 and 29.08?ppm, respectively, after an exposure to 24?h. The cidal effect of the celery seed oil augmented by 1.2-fold; after an exposure to 48?h; revealing an LC50 value of 13.22?ppm. Interestingly, the seed oil did not cause immediate larval mortality, suggesting a delayed toxicity against the larval stage. Present investigations also revealed remarkable effective repellency of the oil leading to 100% protection till 165?min as compared to control that did not result in any repellency against adult Ae. aegypti. Interestingly, only one bite was recorded in the 165th-min after which only two bites were scored until 180?min of exposure of the adult mosquitoes to the oil. An exciting observation was that the knocked-down effect in adults exposed to 10% oil-impregnated papers. The contact irritancy assays with paper impregnated with 1% celery seed oil caused first flight only after 4?s resulting in an average of 63.66 flights during 15?min of exposure revealing the relative irritability of 26.97. The qualitative phytochemical analysis of the seed oil showed the presence of flavonoids, lactones, and terpenoids as the major constituents suggesting their probable role in the toxicity. Our results confirmed that celery seed essential oil can be used as an efficient larvicide and repellent against Ae. aegypti. The identification of the bioactive components, their mode of action, and studying effects on non-target organisms and the environment would help in devising mosquito-management strategies. PMID:25279371

Kumar, Sarita; Mishra, Monika; Wahab, Naim; Warikoo, Radhika

2014-01-01

271

Shuttle vectors for hyperthermophilic archaea.  

Science.gov (United States)

Progress in understanding the basic molecular, biochemical, and physiological characteristics of archaeal hyperthermophiles has been limited by the lack of suitable expression vectors. Here, we report the construction of versatile shuttle vectors that can be maintained, and selected for, in both archaea and bacteria. The primary construct, pAG1, was produced by ligating portions of the archaeal cryptic plasmid pGT5 and the bacterial plasmid pUC19, both of which exhibit high copy numbers. A second vector construct, pAG2, was generated, with a reduced copy number in Escherichia coli, by introducing the Rom/Rop gene from pBR322 into pAG1. After transformation, both pAG1 and pAG2 were stably maintained and propagated in the euryarchaeote Pyrococcus furiosus, the crenarchaeote Sulfolobus acidocaldarius, and in Escherichia coli. An archaeal selective marker, the alcohol dehydrogenase gene from Sulfolobus solfataricus, was isolated by polymerase chain reaction (PCR) amplification and cloned into the two constructs. They were stably maintained and expressed in the two archaea and conferred resistance to butanol and benzyl alcohol. However, the vector pAG21, deriving from pAG2, proved the more stable in E. coli probably due to its lower copy number in the bacterium. Conditions are presented for the use of the vectors which, potentially, can be used for other hyperthermophilic archaea. PMID:9680299

Aravalli, R N; Garrett, R A

1997-11-01

272

Vector piezoresponse force microscopy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A novel approach for nanoscale imaging and characterization of the orientation dependence of electromechanical properties-vector piezoresponse force microscopy (Vector PFM)-is described. The relationship between local electromechanical response, polarization, piezoelectric constants, and crystallographic orientation is analyzed in detail. The image formation mechanism in vector PFM is discussed. Conditions for complete three-dimensional (313) reconstruction of the electromechanical response v...

Kalinin, S. V.; Rodriguez, Brian J.; Jesse, S.; et al,

2006-01-01

273

Novel vaccine vectors for HIV-1  

Science.gov (United States)

The ultimate solution to the global HIV-1 epidemic will probably require the development of a safe and effective vaccine. Multiple vaccine platforms have been evaluated in both preclinical and clinical trials, but, given the disappointing results of the clinical efficacy studies so far, novel vaccine approaches are needed. In this Opinion article, we discuss the scientific basis and clinical potential of novel adenovirus and cytomegalovirus vaccine vectors for HIV-1 as two contrasting, but potentially complementary, vector approaches. Both of these vector platforms have demonstrated partial protection against stringent simian immunodeficiency virus challenges in rhesus monkeys using different immunological mechanisms. PMID:25296195

Picker, Louis J.

2014-01-01

274

Summation of vectors  

Science.gov (United States)

This EJS model allows the user to graphically add several vectors. The user can change the number of vectors and the size and direction of each vector. The simulation computes the vector sum. The components of each of the vectors can also be shown. This Model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ntnu_vectorsum.jar file will run the program if a Java runtime is installed.

Hwang, Fu-Kwun

2010-12-25

275

Subretinal gene delivery using helper-dependent adenoviral vectors  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract This study describes the successful delivery of helper-dependent adenoviral vectors to the mouse retina with long term and robust levels of reporter expression in the retina without apparent adverse effects. Since these vectors have a large cloning capacity, they have great potential to extend the success of gene therapy achieved using the adeno-associated viral vector.

Wu Linda

2011-04-01

276

The Hertz vector revisited: a simple physical picture  

Science.gov (United States)

The polarization potentials, also known as Hertz vectors, are useful auxiliary fields that permit the calculation of the fundamental electromagnetic fields in many cases of practical importance. In this article we show that in a vacuum a single Hertz vector written as the product of a scalar potential and a constant vector, naturally arises as consequence of the transversality of the electromagnetic fields. Thus, our treatment shines a new light on the physical meaning of a Hertz potential.

Ornigotti, Marco; Aiello, Andrea

2014-10-01

277

Nutritional ecology of the malaria vector Anopheles gambiae  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Vector survival rate is a key factor when estimating the potential of a vector population to transmit a parasite and as such, a small change in vector survival can have a significant effect on vectorial capacity. Using laboratory experiments, I investigated the possibility that Anopheles gambiae, a vector of Plasmodium, can alter the proportional allocation of resources between somatic and reproductive functions in response to limited nutritional intake. I also conducted a field survey to doc...

Walker, Kelly Lee

2008-01-01

278

Survey of cyclopids (Crustacea, Copepoda in Brazil and preliminary screening of their potential as dengue vector predators Levantamento de ciclopídeos (Crustacea, Copepoda no Brasil e avaliação preliminar de seu potencial como predadores dos vetores da dengue  

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.INTRODUÇÃO: Copépodos ciclopídeos são conhecidos como bons controladores de mosquitos, especialmente quando considerado as larvas dos vetores da dengue Aedes aegypti e Ae. albopictus. MATERIAL E MÉTODO: Onze corpos d'água em Campinas, SP, Brasil, foram avaliados para copépodos coletando-se 1,5 l de água de cada um deles. O potencial predador dos copépodos adultos foi avaliado por 24 h, em laboratório, em grupos de 5 indivíduos predadando sobre 30 larvas de 1° estádio de Ae. albopictus. RESULTADOS E CONCLUSÕES: No presente levantamento as seguintes espécies de ciclopídeos foram encontradas: Metacyclops mendocinus, Tropocyclops prasinus, Eucyclops sp, Eucyclops serrulatus, Eucyclops solitarius, Eucyclops ensifer, Macrocyclops albidus var. albidus and Mesocyclops longisetus var. longisetus. O potencial predador desses copépodos variou de zero a 97,3%. A amostra coletada no campo contendo apenas com M. longisetus var. longisetus mostrou a melhor eficiência de controle, sem diferença significativa de uma cultura de laboratório (ML-01 criada por 3 anos, desta mesma espécie, que foi avaliada para comparação. A amostra com poucos M. albidus var. albidus foi cotada em segundo melhor lugar, apresentando em média 25,9% de eficiência. O uso de copépodos em pneus armadilha como controladores dos vetores da dengue é discutido.

Luciana Urbano dos Santos

1997-06-01

279

Tensor and vector analyzing powers of the 1H( vector d,pp)n reaction  

International Nuclear Information System (INIS)

Tensor analyzing powers Axx and Ayy and vector analyzing powers Ay of the 1H( vector d,pp)n breakup reaction at Ed=52.1 MeV were measured in the symmetric collinear and coplanar-star kinematic configurations. The experimental results are compared with rigorous three-nucleon continuum calculations using realistic nucleon-nucleon potentials. ((orig.))

280

Biosecurity and vector behaviour: evaluating the potential threat posed by anglers and canoeists as pathways for the spread of invasive non-native species and pathogens.  

Science.gov (United States)

Invasive non-native species (INNS) endanger native biodiversity and are a major economic problem. The management of pathways to prevent their introduction and establishment is a key target in the Convention on Biological Diversity's Aichi biodiversity targets for 2020. Freshwater environments are particularly susceptible to invasions as they are exposed to multiple introduction pathways, including non-native fish stocking and the release of boat ballast water. Since many freshwater INNS and aquatic pathogens can survive for several days in damp environments, there is potential for transport between water catchments on the equipment used by recreational anglers and canoeists. To quantify this biosecurity risk, we conducted an online questionnaire with 960 anglers and 599 canoeists to investigate their locations of activity, equipment used, and how frequently equipment was cleaned and/or dried after use. Anglers were also asked about their use and disposal of live bait. Our results indicate that 64% of anglers and 78.5% of canoeists use their equipment/boat in more than one catchment within a fortnight, the survival time of many of the INNS and pathogens considered in this study and that 12% of anglers and 50% of canoeists do so without either cleaning or drying their kit between uses. Furthermore, 8% of anglers and 28% of canoeists had used their equipment overseas without cleaning or drying it after each use which could facilitate both the introduction and secondary spread of INNS in the UK. Our results provide a baseline against which to evaluate the effectiveness of future biosecurity awareness campaigns, and identify groups to target with biosecurity awareness information. Our results also indicate that the biosecurity practices of these groups must improve to reduce the likelihood of inadvertently spreading INNS and pathogens through these activities. PMID:24717714

Anderson, Lucy G; White, Piran C L; Stebbing, Paul D; Stentiford, Grant D; Dunn, Alison M

2014-01-01

 
 
 
 
281

Cross-resistance, genetics, and realized heritability of resistance to fipronil in the house fly, Musca domestica (Diptera: Muscidae): a potential vector for disease transmission.  

Science.gov (United States)

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

282

Integrated strategy for the production of therapeutic retroviral vectors.  

Science.gov (United States)

The broad application of retroviral vectors for gene delivery is still hampered by the difficulty to reproducibly establish high vector producer cell lines generating sufficient amounts of highly concentrated virus vector preparations of high quality. To enhance the process for producing clinically relevant retroviral vector preparations for therapeutic applications, we have integrated novel and state-of-the-art technologies in a process that allows rapid access to high-efficiency vector-producing cells and consistent production, purification, and storage of retroviral vectors. The process has been designed for various types of retroviral vectors for clinical application and to support a high-throughput process. New modular helper cell lines that permit rapid insertion of DNA encoding the therapeutic vector of interest at predetermined, optimal chromosomal loci were developed to facilitate stable and high vector production levels. Packaging cell lines, cultivation methods, and improved medium composition were coupled with vector purification and storage process strategies that yield maximal vector infectivity and stability. To facilitate GMP-grade vector production, standard of operation protocols were established. These processes were validated by production of retroviral vector lots that drive the expression of type VII collagen (Col7) for the treatment of a skin genetic disease, dystrophic epidermolysis bullosa. The potential efficacy of the Col7-expressing vectors was finally proven with newly developed systems, in particular in target primary keratinocyte cultures and three-dimensional skin tissues in organ culture. PMID:21043806

Carrondo, Manuel; Panet, Amos; Wirth, Dagmar; Coroadinha, Ana Sofia; Cruz, Pedro; Falk, Haya; Schucht, Roland; Dupont, Francis; Geny-Fiamma, Cécile; Merten, Otto-Wilhelm; Hauser, Hansjörg

2011-03-01

283

Vector Soliton Fiber Lasers  

CERN Document Server

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

284

Interframe vector wavelet coding technique  

Science.gov (United States)

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

285

Custodial Vector Model  

CERN Document Server

We analyze the Large Hadron Collider (LHC) phenomenology of heavy vector resonances with a $SU(2)_L\\times SU(2)_R$ spectral global symmetry. This symmetry partially protects the electroweak S-parameter from large contributions of the vector resonances. The resulting custodial vector model spectrum and interactions with the standard model fields lead to distinct signatures at the LHC in the diboson, dilepton and associated Higgs channels.

Becciolini, Diego; Foadi, Roshan; Frandsen, Mads T; Hapola, Tuomas; Sannino, Francesco

2014-01-01

286

Complex vector functional equations  

CERN Document Server

The subject of complex vector functional equations is a new area in the theory of functional equations. This monograph provides a systematic overview of the authors' recently obtained results concerning both linear and nonlinear complex vector functional equations, in all aspects of their utilization. It is intended for mathematicians, physicists and engineers who use functional equations in their investigations. Contents: Linear Complex Vector Functional Equations: General Classes of Cyclic Functional Equations; Functional Equations with Operations Between Arguments; Functional Equations with

Risteski, Ice

2001-01-01

287

Vector curvaton without instabilities  

International Nuclear Information System (INIS)

A vector curvaton model with a Maxwell kinetic term and varying kinetic function and mass during inflation is studied. It is shown that, if light until the end of inflation, the vector field can generate statistical anisotropy in the curvature perturbation spectrum and bispectrum, with the latter being predominantly anisotropic. If by the end of inflation the vector field becomes heavy, then particle production is isotropic and the vector curvaton can alone generate the curvature perturbation. The model does not suffer from instabilities such as ghosts and is the only concrete model, to date, which can produce the curvature perturbation without direct involvement of fundamental scalar fields.

288

[Micronecta sp (Corixidae) and Diplonychus sp (Belostomatidae), two aquatic Hemiptera hosts and/or potential vectors of Mycobacterium ulcerans (pathogenic agent of Buruli ulcer) in Cote d'Ivoire].  

Science.gov (United States)

Buruli ulcer is currently a major public health problem in Côte d'Ivoire. It is a neglected tropical disease closely associated with aquatic environments. Aquatic insects of the Hemiptera order have been implicated in human transmission of Mycobacterium ulcerans, the pathogenic agent of Buruli ulcer. The purpose of this preliminary study using the polymerase chain reaction (PCR) method was to evaluate aquatic insects in Sokrogbo, a village in the Tiassalé sanitary district where Buruli ulcer is endemic. Findings identified two water bugs hosting Mycobacterium ulcerans, i.e., one of the Micronecta genus in the Corixidae family and another of the Diplonychus genus in the Belostomatidae family. The PCR technique used revealed the molecular signatures of M. ulcerans in tissue from these two insects. Based on these findings, these two water bugs can be considered as potential hosts and/or vectors of M. ulcerans in the study zone. Unlike Diplonychus sp., this is the first report to describe Micronecta sp as a host of M. ulcerans. Further investigation will be needed to assess the role of these two water bugs in human transmission of M. ulcerans in Côte d'Ivoire. PMID:21585092

Doannio, J M C; Konan, K L; Dosso, F N; Koné, A B; Konan, Y L; Sankaré, Y; Ekaza, E; Coulibaly, N D; Odéhouri, K P; Dosso, M; Sess, E D; Marsollier, L; Aubry, J

2011-02-01

289

Pulsed Vector Magnetic Potential Field Existence  

Directory of Open Access Journals (Sweden)

Full Text Available 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

2012-11-01

290

Brane vector phenomenology  

International Nuclear Information System (INIS)

Local oscillations of the brane world are manifested as massive vector fields. Their coupling to the Standard Model can be obtained using the method of nonlinear realizations of the spontaneously broken higher-dimensional space-time symmetries, and to an extent, are model independent. Phenomenological limits on these vector field parameters are obtained using LEP collider data and dark matter constraints

291

Viruses | Special Issue : Retroviral Vectors  

...Marine Drugs Materials Mathematics Medical Sciences Membranes Metabolites Metals Microarrays Micromachines Microorganisms Minerals Molbank Molecules Nanomaterials Nutrients Pathogens Pharmaceuticals Pharmaceutics Pharmacy Plants Polymers Processes Proteomes Publications Religions Remote Sensing Resources Risks Robotics Sensors Social Sciences Societies Sports Sustainability Symmetry Systems Technologies Toxics Toxins Vaccines Veterinary Sciences Viruses Water Volume Author Section Issue Article Type all Addendum Article Book Review Case Report Comment Commentary Communication Concept Paper Correction Creative Discussion Editorial ...3390/v3050429 Received: 9 February 2011; in revised form: 24 March 2011 / Accepted: 5 April 2011 / Published: 29 April 2011 Show/Hide Abstract | Download PDF Full-text (687 KB) Abstract: The curative potential of retroviral vectors for somatic gene therapy has been demonstrated impressively in several clinical trials leading to sustained long-term correction of the underlying genetic defect. Preclinical studies and clinical monitoring of gene modified hematopoietic stem and progenitor cells in patients have shown that biologically relevant vector induced side ...

292

Retroviral Vector Biosafety: Lessons from Sheep  

Directory of Open Access Journals (Sweden)

Full Text Available The safety of retroviral-based systems and the possible transmission of replication-competent virus to patients is a major concern associated with using retroviral vectors for gene therapy. While much effort has been put into the design of safe retroviral production methods and effective in vitro monitoring assays, there is little data evaluating the risks resulting from retroviral vector instability at post-transduction stages especially following in vivo gene delivery. Here, we briefly describe and discuss our observations in an in vivo experimental model based on the inoculation of retroviral vector-transduced tumor cells in sheep. Our data indicates that the in vivo generation of mosaic viruses is a dynamic process and that virus variants, generated by retroviral vector-mediated recombination, may be stored and persist in infected individuals prior to selection at the level of replication. Recombination may not only restore essential viral functions or provide selective advantages in a changing environment but also reestablish or enhance the pathogenic potential of the particular virus undergoing recombination. These observations in sheep break new ground in our understanding of how retroviral vectors may have an impact on the course of a preestablished disease or reactivate dormant or endogenous viruses. The in vivo aspects of vector stability raise important biosafety issues for the future development of safe retroviral vector-based gene therapy.

Van den Broeke Anne

2003-01-01

293

Boosting Support Vector Machines  

Directory of Open Access Journals (Sweden)

Full Text Available En este artículo, se presenta un algoritmo de clasificación binaria basado en Support Vector Machines (Máquinas de Vectores de Soporte que combinado apropiadamente con técnicas de Boosting consigue un mejor desempeño en cuanto a tiempo de entrenamiento y conserva características similares de generalización con un modelo de igual complejidad pero de representación más compacta./ In this paper we present an algorithm of binary classification based on Support Vector Machines. It is combined with a modified Boosting algorithm. It run faster than the original SVM algorithm with a similar generalization error and equal complexity model but it has more compact representation.

Elkin Eduardo García Díaz

2006-11-01

294

Polarimetric vector diffraction tomography  

Science.gov (United States)

Scalar linearized inverse scattering has recently found a unified treatment within the framework of diffraction tomography in either frequency or angular diversity. The linear inverse scattering theory can be extended to electromagnetic vector fields to include complete polarization information. Its essential feature is the formulation of a vector Porter-Bojarski integral equation to be inverted by dyadic algebra. Algorithms are discussed for frequency diversity within linearized approximations for perfectly conducting and weak scattering objects, respectively. Particularly, a vector Fourier diffraction slice theorem has been obtained. These algorithms are checked against synthetic data obtained with a FDTD-code (MAFIA) to prove whether they offer advantages over non-polarimetric tomography. Hence, the FDTD-code is utilized to obtain synthetic data for a variety of scattering geometries to demonstrate the performance of vector diffraction tomography.

Brandfass, Michael; Langenberg, Karl J.; Fritsch, A.

1994-09-01

295

Poynting-vector filter  

Science.gov (United States)

A determination is made of frequency components associated with a particular bearing or location resulting from sources emitting electromagnetic-wave energy for which a Poynting-Vector can be defined. The broadband frequency components associated with a specific direction or location of interest are isolated from other components in the power spectrum that are not associated with the direction or location of interest. The collection of pointing vectors can be used to characterize the source.

Carrigan, Charles R. (Tracy, CA)

2011-08-02

296

The Vector Curvaton  

CERN Document Server

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

297

Equivalent local Dirac potentials  

Science.gov (United States)

A transformation is used to obtain sets of equivalent Lorentz scalar, Lorentz four-vector, and tensor optical potentials. These potentials are used in the Dirac equation for describing elastic scattering observables.

Clark, B. C.; Hama, S.; Kalbermann, S. G.; Cooper, E. D.; Mercer, R. L.

1985-02-01

298

Towards a new role for vector systematics in parasite control.  

Science.gov (United States)

Vector systematics research is being transformed by the recent development of theoretical, experimental and analytical methods, as well as conceptual insights into speciation and reconstruction of evolutionary history. We review this progress using examples from the mosquito genus Anopheles. The conclusion is that recent progress, particularly in the development of better tools for understanding evolutionary history, makes systematics much more informative for vector control purposes, and has increasing potential to inform and improve targeted vector control programmes. PMID:21679487

Zarowiecki, Magdalena; Loaiza, Jose R; Conn, Jan E

2011-11-01

299

Transgenic control of vectors: the effects of interspecific interactions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The control of insect vectors through conventional sterile insect or transgenic technologies (e.g., RIDL®) is an intense focus of research in the combat against vector-borne disease. While the population dynamic implications of these control strategies are reasonably well-established, the effects of interspecific competition between different vectors and control strategies have not previously been explored. Different control intervention methods can affect the interaction and potential coexi...

Bonsall, Mb; Yakob, L.; Alphey, N.; Alphey, L.

2010-01-01

300

Vectorization in quantum chemistry  

International Nuclear Information System (INIS)

It is argued that the optimal vectorization algorithm for many steps (and sub-steps) in a typical ab initio calculation of molecular electronic structure is quite strongly dependent on the target vector machine. Details such as the availability (or lack) of a given vector construct in the hardware, vector startup times and asymptotic rates must all be considered when selecting the optimal algorithm. Illustrations are drawn from: gaussian integral evaluation, fock matrix construction, 4-index transformation of molecular integrals, direct-CI methods, the matrix multiply operation. A cross comparison of practical implementations on the CDC Cyber 205, the Cray-IS and Cray-XMP machines is presented. To achieve portability while remaining optimal on a wide range of machines it is necessary to code all available algorithms in a machine independent manner, and to select the appropriate algorithm using a procedure which is based on machine dependent parameters. Most such parameters concern the timing of certain vector loop kernals, which can usually be derived from a 'bench-marking' routine executed prior to the calculation proper

 
 
 
 
301

Mycobacteriophage vector systems.  

Science.gov (United States)

Successful application of molecular genetic approaches to the study of mycobacteria necessitates the introduction of recombinant DNA molecules into mycobacterial cells. Efficient methods of introducing DNA into Mycobacterium smegmatis protoplasts have been developed, and the construction of mycobacteriophage recombinant DNA vectors has been initiated. Novel Escherichia coli-Mycobacterium shuttle vectors, termed shuttle phasmids, have been constructed. These vectors were constructed by inserting E. coli cosmids into nonessential regions of mycobacteriophage DNAs. Shuttle phasmids are multifunctional vectors that replicate in E. coli as plasmids and replicate in mycobacteria as phage. The presence of the bacteriophage lambda cos sequences permits the use of the lambda in vitro packaging system for efficient cloning of additional genes into these vectors. Temperate shuttle phasmids have been constructed that can infect and lyse mycobacterial cells or lysogenize mycobacterial cells to stably integrate and express cloned DNA into mycobacterial genomes. Shuttle phasmids can be transduced into a wide variety of mycobacterial species and thus should permit the development of molecular genetic systems for the mycobacteria. PMID:2652256

Jacobs, W R; Snapper, S B; Tuckman, M; Bloom, B R

1989-01-01

302

Vector WIMP Miracle  

CERN Document Server

Weakly interacting massive particle (WIMP) is well known to be a good candidate for dark matter, and it is also predicted by many new physics models beyond the standard model at the TeV scale. We found that, if the WIMP is a vector particle (spin one particle) which is associated with some gauge symmetry broken at the TeV scale, the higgs mass is often predicted to be 120--125 GeV, which is very consistent with the result of higgs searches recently reported by ATLAS and CMS collaborations at the Large Hadron Collider experiment. In this letter, we consider the vector WIMP using a non-linear sigma model in order to confirm this result as general as possible in a bottom-up approach. Near-future prospects to detect the vector WIMP at both direct and indirect detection experiments of dark matter are also discussed.

Abe, Tomohiro; Matsumoto, Shigeki; Seto, Osamu

2012-01-01

303

Heavy vector mesons  

International Nuclear Information System (INIS)

The current status of heavy vector meson resonances in the prime rho, prime ? and prime phi families is discussed in the light of recent results, particularly from the CERN photoproduction experiment WA4. It is shown that the results from recent high statistics ?p and e+e- experiments have clarified the confused state of heavy vector meson spectroscopy somewhat but the tentative nature of the conclusions reached emphasises the fact that light quark radial excitations are still less well understood than upsilon radial excitations. (U.K.)

304

Analysis in Vector Spaces  

CERN Document Server

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

305

Vector Addition with Integer Components  

Science.gov (United States)

The Vector Addition with Integer Components model allows the user to split a vector into its components, and practice finding the magnitude and direction of a vector if you know the components. In this simulation the x and y components of each vector are all integers. In the "Find components" mode, you are given the magnitude and direction of the vector, and your goal is to find the x-component and the y-component of the vector. In the "Find magnitude and direction" mode, you are given the two components, and you need to find the magnitude and direction of the vector. The Vector Addition with Integer Components model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_bu_vector_components_integer.jar file will run the program if Java is installed.

Duffy, Andrew

2010-05-02

306

Support vector machines  

Science.gov (United States)

Support Vector Machines (SVMs) are a type of supervised learning algorith,, other examples of which are Artificial Neural Networks (ANNs), Decision Trees, and Naive Bayesian Classifiers. Supervised learning algorithms are used to classify objects labled by a 'supervisor' - typically a human 'expert.'.

Garay, Michael J.; Mazzoni, Dominic; Davies, Roger; Wagstaff, Kiri

2004-01-01

307

Vector-borne Infections  

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

308

Random and vector measures  

CERN Document Server

The book is devoted to the structural analysis of vector and random (or both) valued countably additive measures, and used for integral representations of random fields. The spaces can be Banach or Frechet types. Several stationary aspects and related processes are analyzed whilst numerous new results are included and many research avenues are opened up.

Rao, M M

2011-01-01

309

Calculus with vectors  

CERN Document Server

Calculus with Vectors grew out of a strong need for a beginning calculus textbook for undergraduates who intend to pursue careers in STEM. fields. The approach introduces vector-valued functions from the start, emphasizing the connections between one-variable and multi-variable calculus. The text includes early vectors and early transcendentals and includes a rigorous but informal approach to vectors. Examples and focused applications are well presented along with an abundance of motivating exercises. All three-dimensional graphs have rotatable versions included as extra source materials and may be freely downloaded and manipulated with Maple Player; a free Maple Player App is available for the iPad on iTunes. The approaches taken to topics such as the derivation of the derivatives of sine and cosine, the approach to limits, and the use of "tables" of integration have been modified from the standards seen in other textbooks in order to maximize the ease with which students may comprehend the material. Additio...

Treiman, Jay S

2014-01-01

310

Isotropy theorem for cosmological vector fields  

CERN Document Server

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

311

Meromorphic Vector Fields and Circle Packings  

DEFF Research Database (Denmark)

The objective of the Ph.D. project is to initiate a classification of bifurcations of meromorphic vector fields and to clarify their relation to circle packings. Technological applications are to image analysis and to effective grid generation using discrete conformal mappings. The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions or meromorphic (allowing poles as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic vector fields. Restricting to structurally stable vector fields, there is an underlying dynamically defined triangulation of the plane. Circle packings are a means to realize such a given combinatorial structure. About 20 years ago, W. Thurston suggested applying circle packings to obtain approximations to Riemann mappings. This gave rise to the development of a theory of discrete analytic functions, which is a new tool in conformal geometry that can be used to implement many of the classical tools from complex analysis. Circle packing is a relatively new subject that has a great potential for technological applications, specifically for imaging problems. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition of parameter spaces into structurally stable domains, and a description of the bifurcations. The same holds true for questions related to vector fields on the Riemann sphere and Riemann surfaces of higher genus. The overall objectives of this Ph.D.-study are to characterize the decomposition of parameter spaces of meromorphic vector fields on Riemann surfaces of low genus and a description of the bifurcations and to implement characteristic vector fields on such surfaces using circle packings. Furthermore, when the implementations using circle packings have been established, applications in conformal geometry and image analysis will be investigated in collaboration with faculty members at MAT and IMM.

Dias, Kealey

2009-01-01

312

Insect Vectors of Human Pathogens  

Science.gov (United States)

Four orders of insects (Hemiptera, Phthiraptera, Diptera, and Siphonaptera) are covered detailing vector species along with their pathogens of human importance. Links to pathogens as well as vectors are highlighted (some of these are CDC, and WHO).

0002-11-30

313

Multi Matrix Vector Coherent States  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A class of vector coherent states is derived with multiple of matrices as vectors in a Hilbert space, where the Hilbert space is taken to be the tensor product of several other Hilbert spaces. As examples vector coherent states with multiple of quaternions and octonions are given. The resulting generalized oscillator algebra is briefly discussed. Further, vector coherent states for a tensored Hamiltonian system are obtained by the same method. As particular cases, coherent s...

Thirulogasanthar, K.; Honnouvo, G.; Krzyzak, A.

2003-01-01

314

Fluidic thrust vector control  

Science.gov (United States)

The design and testing of a fluidic control nozzle for tactical missile thrust vector control (TVC) are discussed. Attention is given to a nozzle with a circular cross section up to the point of flow separation, two control ports that alternately open and close, and a nozzle extension downstream of the control ports being a two-dimensional rectangular slot. Design of the TVC system involved characterizing the flow and the sensitivity parameters, the dynamic response, and the performance of hot-gas firings. The test firings verified the feasibility of a nozzle that could withstand 5000 F, the use of thrust vector angles of over 20 deg. A dynamic model test demonstrated a repeatable performance with pressures up to 2000 psia, driving frequencies up to 50 Hz, and a response of 10-15 msec. Adjustment of the chamber pressures permitted equivalent performance using with different heat ratios during cold dynamic tests with CH4.

Haloulakos, V. E.

315

Vector Machine Inverse  

Directory of Open Access Journals (Sweden)

Full Text Available In order to achieve the online detection problem of rotor speed for Bearingless Induction Motor (BIM, a speed identification scheme based on the Least Square Support Vector Machine (LSSVM inverse is presented in this study. According to the inherent relationship among the variables of BIM, the speed subsystem is first built and proved to be invertible. Secondly, the inverse model was constructed using LSSVM which has good function approximation characteristics. And then the obtained inverse model is combined with this subsystem, which well realized the real-time rotation speed identification. Finally, a vector control simulation platform of BIM is established to evaluate the proposed method. The simulation results demonstrates the proposed LSSVM inverse method can accurately identify the speed parameter in a full speed operation region with good dynamic and static performance.

Zebin Yang

2013-01-01

316

Helices and vector bundles  

CERN Document Server

This volume is devoted to the use of helices as a method for studying exceptional vector bundles, an important and natural concept in algebraic geometry. The work arises out of a series of seminars organised in Moscow by A. N. Rudakov. The first article sets up the general machinery, and later ones explore its use in various contexts. As to be expected, the approach is concrete; the theory is considered for quadrics, ruled surfaces, K3 surfaces and P3(C).

Rudakov, A N

1990-01-01

317

Chameleon Vector Bosons  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We show that for a force mediated by a vector particle coupled to a conserved U(1) charge, the apparent range and strength can depend on the size and density of the source, and the proximity to other sources. This "chameleon" effect is due to screening from a light charged scalar. Such screening can weaken astrophysical constraints on new gauge bosons. As an example we consider the constraints on chameleonic gauged B-L. We show that although Casimir measurements greatly cons...

Nelson, Ann E.; Walsh, Jonathan

2008-01-01

318

Chiral QHD with vector mesons  

International Nuclear Information System (INIS)

We construct a chiral-invariant Yang-Mills theory based on the local gauge symmetry SU(2)R x SU(2)L. The baryon mass is generated through spontaneous symmetry breaking (as in the linear sigma model), and the vector meson masses are produced through the Higgs mechanism. The theory is parity conserving. Two baryon isodoublets with opposite hypercharge y are necessary to eliminate chiral anomalies. The minimal set of hadrons required consists of [N, ?; ?, ?, ?, p, a; ?, ?], where a is the chiral partner of the p (the a naturally obtains a higher mass in the model), and the ? and ? represent scalar and psedoscalar Higgs particles. The parameters in this minimal theory consists of eight coupling constants and one mass (gw, g0? + yg1?, gp, ?M2, ?M, ?H2, ?H, m?), where ?2 and ? define the meson interaction potentials that lead to spontaneous symmetry breaking. 2 figs., 28 refs. (author)

319

Leishmaniasis vector behaviour in Kenya  

International Nuclear Information System (INIS)

Leishmaniasis in Kenya exists in two forms: cutaneous and visceral. The vectors of visceral leishmaniasis have been the subject of investigation by various researchers since World War II, when the outbreak of the disease was first noticed. The vectors of cutaneous leishmaniasis were first worked on only a decade ago after the discovery of the disease focus in Mt. Elgon. The vector behaviour of these diseases, namely Phlebotomus pedifer, the vector of cutaneous leishmaniasis, and Phlebotomus martini, the vector of visceral leishmaniasis, are discussed in detail. P. pedifer has been found to breed and bite inside caves, whereas P. martini mainly bites inside houses. (author)

320

Vector control in some countries of Southeast Asia: comparing the vectors and the strategies.  

Science.gov (United States)

The use of information on malaria vector behaviour in vector control is discussed in relation to the area of Southeast Asia comprising Cambodia, Laos, Myanmar, Thailand and Vietnam. The major vectors in the region are Anopheles dirus, An. minimus, An. maculatus and An. sundaicus, of which An. dirus is the most important. Options for vector control and the biological features of mosquitoes, which would make them amenable to control by these measures, are listed. The methods with the greatest potential for controlling each of the four vector species are described. Experiences of vector control by residual spraying, insecticide-treated nets and larva control and of personal protection against the four vectors are outlined, and it is noted that choice of control strategy is often determined by epidemiological, economic and political considerations, whilst entomological observations may help to explain failures of control and to indicate alternative strategies. Future research needs include basic entomological field studies using the most appropriate indicators to detect changes related to rapidly changing environmental conditions, such as loss of forest and climate change. Further studies of the efficacy of insecticide-treated mosquito nets, with greater attention to study design, are needed before it can be assumed that they will work in Southeast Asia. At the same time, research to improve sustainable utilization of nets is important, bearing in mind that nets are not the only means to control malaria and should not drain resources from supervision and training, which improve access to diagnosis and treatment of malaria and other diseases. Research is needed to make decisions on whether vector control is appropriate in different environments, and, if so, how to carry it out in different health systems. Researchers need to play a greater role in making operational research (entomological, epidemiological, social, economic and health systems research) of good quality an integral component of implementation programmes. PMID:7605123

Meek, S R

1995-04-01

 
 
 
 
321

Mobilization of DNA transposable elements from lentiviral vectors.  

Science.gov (United States)

With the Sleeping Beauty (SB) DNA transposon, a reconstructed Tc1/mariner element, as the driving force, DNA transposable elements have emerged as new gene delivery vectors with therapeutic potential. The bipartite transposon vector system consists of a transposon vector carrying the transgene and a source of the transposase that catalyzes transposon mobilization. The components of the system are typically residing on separate plasmids that are transfected into cells or tissues of interest. We have recently shown that SB vector technology can be successfully combined with lentiviral delivery. Hence, SB transposons are efficiently mobilized from HIV-based integrase-defective lentiviral vectors by the hyperactive SB100X transposase, leading to the genomic insertion of lentivirally delivered DNA in a reaction controlled by a nonviral integration machinery. This new technology combines the better of two vector worlds and leads to integration profiles that are significantly altered and potentially safer relative to conventional lentiviral vectors. In this short commentary, we discuss our recent findings and the road ahead for hybrid lentivirus-transposon vectors. PMID:22016863

Bak, Rasmus O; Mikkelsen, Jacob Giehm

2011-07-01

322

[Climate- and vector-borne diseases  

DEFF Research Database (Denmark)

The predicted changes in climate have raised concerns that vector-borne diseases may emerge or expand in tempered regions. Malaria, leishmaniasis and tick-borne illnesses are discussed in terms of climate change and their endemic potential, especially in Denmark. While climate may play an important role in disease patterns, it is evident that transmission potential is governed by a complex of factors, including socio-economy, health-care capacity and ecology. In Denmark, malaria and leishmaniasis are unlikely to become public health problems, whereas the potential for tick-borne illnesses may increase Udgivelsesdato: 2009/10/26

Bygbjerg, I.C.; Schioler, K.L.

2009-01-01

323

From population structure to genetically-engineered vectors: new ways to control vector-borne diseases?  

Science.gov (United States)

Epidemiological studies on vectors and the pathogens they can carry (such as Borrelia burgdorferi) are showing some correlations between infection rates and biodiversity highlighting the "dilution" effects on potential vectors. Meanwhile other studies comparing sympatric small rodent species demonstrated that rodent species transmitting more pathogens are parasitized by more ectoparasite species. Studies on population structure and size have also proven a difference on the intensity of the parasitic infection. Furthermore, preliminary results in genetic improvement in mosquitoes (genetic markers, sexing, and genetic sterilization) will also increase performance as it has already been shown in field applications in developing countries. Recent results have greatly improved the fitness of genetically-modified insects compared to wild type populations with new approaches such as the post-integration elimination of transposon sequences, stabilising any insertion in genetically-modified insects. Encouraging results using the Sterile Insect Technique highlighted some metabolism manipulation to avoid the viability of offspring from released parent insect in the wild. Recent studies on vector symbionts would also bring a new angle in vector control capabilities, while complete DNA sequencing of some arthropods could point out ways to block the deadly impact on animal and human populations. These new potential approaches will improve the levels of control or even in some cases would eradicate vector species and consequently the vector-borne diseases they can transmit. In this paper we review some of the population biology theories, biological control methods, and the genetic techniques that have been published in the last years that are recommended to control for vector-borne diseases. PMID:17560836

Sparagano, O A E; De Luna, C J

2008-07-01

324

Mathematical tables vector entities  

CERN Document Server

Students and research workers in mathematics, physics, engineering and other sciences will find this compilation invaluable. All the information included is practical, rarely used results are excluded. Great care has been taken to present all results concisely and clearly. Excellent to keep as a handy reference! If you don't have a lot of time but want to excel in class, this book helps you: Brush up before tests Find answers fast Learn key formulas and tables Study quickly and more effectively Inside this guide, you will find: Most important Vector Identities Clear and concise explanations of

2010-01-01

325

Nomograms for Visualizing Support Vector Machines  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We propose a simple yet potentially very effective way of visualizing trained support vector machines. Nomograms are an established model visualization technique that can graphically encode the complete model on a single page. The dimensionality of the visualization does not depend on the number of attributes, but merely on the properties of the kernel. To represent the effect of each predictive feature on the log odds ratio scale as required for the nomograms, we employ logistic regression t...

Jakulin, Aleks; Moz?ina, Martin; Dems?ar, Janez; Bratko, Ivan; Zupan, Blaz

2005-01-01

326

Canine vector-borne diseases in Brazil  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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) t...

2008-01-01

327

Stabilized two-dimensional vector solitons  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this letter we introduce the concept of stabilized vector solitons as nonlinear waves constructed by addition of mutually incoherent Townes solitons that are stabilized under the effect of a periodic modulation of the nonlinearity. We analyze the stability of this new kind of structures and describe their behavior and formation in Manakov-like interactions. Potential applications of our results in Bose-Einstein condensation and nonlinear optics are also discussed.

Montesinos, Gaspar D.; Perez-garcia, Victor M.; Michinel, Humberto

2003-01-01

328

Stabilized two-dimensional vector solitons  

International Nuclear Information System (INIS)

In this Letter, we introduce the concept of stabilized vector solitons as nonlinear waves constructed by the addition of mutually incoherent fractions of Townes solitons that are stabilized under the effect of a periodic modulation of the nonlinearity. We analyze the stability of these new kinds of structures and describe their behavior and formation in Manakov-like interactions. Potential applications of our results in Bose-Einstein condensation and nonlinear optics are also discussed

329

Vector wave propagation method.  

Science.gov (United States)

In this paper, we extend the scalar wave propagation method (WPM) to vector fields. The WPM [Appl. Opt.32, 4984 (1993)] was introduced in order to overcome the major limitations of the beam propagation method (BPM). With the WPM, the range of application can be extended from the simulation of waveguides to simulation of other optical elements like lenses, prisms and gratings. In that reference it was demonstrated that the wave propagation scheme provides valid results for propagation angles up to 85 degrees and that it is not limited to small index variations in the axis of propagation. Here, we extend the WPM to three-dimensional vectorial fields (VWPMs) by considering the polarization dependent Fresnel coefficients for transmission in each propagation step. The continuity of the electric field is maintained in all three dimensions by an enhanced propagation vector and the transfer matrix. We verify the validity of the method by transmission through a prism and by comparison with the focal distribution from vectorial Debye theory. Furthermore, a two-dimensional grating is simulated and compared with the results from three-dimensional RCWA. Especially for 3D problems, the runtime of the VWPM exhibits special advantage over the RCWA. PMID:20360813

Fertig, M; Brenner, K-H

2010-04-01

330

Experimental demonstration of vector E x vector B plasma divertor  

Energy Technology Data Exchange (ETDEWEB)

The vector E x vector B drift due to an applied radial electric field in a tokamak with poloidal divertor can speed the flow of plasma out of the scrape-off region, and provide a means of externally controlling the flow rate and thus the width of the density fall-off. An experiment in the Wisconsin levitated toroidal octupole, using vector E x vector B drifts alone, demonstrates divertor-like behavior, including 70% reduction of plasma density near the wall and 40% reduction of plasma flux to the wall, with no adverse effects on confinement of the main plasma.

Strait, E.J.; Kerst, D.W.; Sprott, J.C.

1977-01-01

331

Semitopological Vector Spaces and Hyperseminorms  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we introduce and study semitopological vector spaces. The goal is to provide an efficient base for developing the theory of extrafunction spaces in an abstract setting of algebraic systems and topological spaces. Semitopological vector spaces are more general than conventional topological vector spaces, which proved to be very useful for solving many problems in functional analysis. To study semitopological vector spaces, hypermetrics and hyperpseudometrics are introduced and it is demonstrated that hyperseminorms, studied in previous works of the author, induce hyperpseudometrics, while hypernorms induce hypermetrics. Sufficient and necessary conditions for a hyperpseudometric (hypermetric to be induced by a hyperseminorm (hypernorm are found. We also show that semitopological vector spaces are closely related to systems of hyperseminorms. Then defining boundedness and continuity relative to associated systems of hyperseminorms, we study relations between relative boundedness and relative continuity for mappings of vector spaces with systems of hyperseminorms and systems of hypernorms.

Mark Burgin

2013-11-01

332

Downstream processing of lentiviral vectors: releasing bottlenecks.  

Science.gov (United States)

Lentiviral vectors (LVs) hold great potential as gene delivery vehicles. However, the manufacturing and purification of these vectors still present major challenges, mainly because of the low stability of the virus, essentially due to the fragility of the membrane envelope. The main goal of this work was the establishment of a fast, scalable, and robust downstream protocol for LVs, combining microfiltration, anion-exchange, and ultrafiltration membrane technologies toward maximization of infectious LVs recovery. CIM(®) (Convective Interaction Media) monolithic columns with diethylaminoethanol (DEAE) anion exchangers were used for the purification of clarified LV supernatants, allowing infectious vector recoveries of 80%, which is 10% higher than the values currently reported in the literature. These recoveries, combined with the results obtained after optimization of the remaining downstream purification steps, resulted in overall infectious LV yields of 36%. Moreover, the inclusion of a Benzonase step allowed a removal of approximately 99% of DNA impurities. The entire downstream processing strategy herein described was conceived based on disposable and easily scalable technologies. Overall, CIM DEAE columns have shown to be a good alternative for the purification of LVs, since they allow faster processing of the viral bulks and enhanced preservation of virus biological activity, consequently, increasing infectious vector recoveries. PMID:22934827

Bandeira, Vanessa; Peixoto, Cristina; Rodrigues, Ana F; Cruz, Pedro E; Alves, Paula M; Coroadinha, Ana S; Carrondo, Manuel J T

2012-08-01

333

Transfer Entropy on Rank Vectors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Transfer entropy (TE) is a popular measure of information flow found to perform consistently well in different settings. Symbolic transfer entropy (STE) is defined similarly to TE but on the ranks of the components of the reconstructed vectors rather than the reconstructed vectors themselves. First, we correct STE by forming the ranks for the future samples of the response system with regard to the current reconstructed vector. We give the grounds for this modified version o...

Kugiumtzis, Dimitris

2010-01-01

334

Multiband Vector Plasmonic Lattice Solitons  

CERN Document Server

We predict multiband vector Plasmonic Lattice Solitons (PLSs) in metal-dielectric waveguide arrays, in both focusing and defocusing nonlinearities. Such vector solitons consist of two components originating from different transmission bands. By simulating the full nonlinear Maxwell equations (MEs), we demonstrate the diffractionless propagation of vector PLSs and their discrete diffraction when only one component is present. Their subwavelength size characteristics and the influences of metallic losses are also studied.

Kou, Yao; Chen, Xianfeng

2013-01-01

335

Maths Help: Working with Vectors  

Science.gov (United States)

Analysis of a wide range of physical properties such as force, velocity, and acceleration, requires a firm understanding of the mathematics of vectors. This comprehensive Web site covers many aspects of vector algebra and trigonometry. The often-used dot product and cross product are defined, as well as vector representations of lines and planes. Illustrations are used to demonstrate vector analysis and its real-world applications. A few extra sections delve into related topics, including transformation between Cartesian and spherical coordinates. The material is mostly suitable for high school or college students who have taken pre-calculus.

336

Noncausal Bayesian Vector Autoregression  

DEFF Research Database (Denmark)

We propose a Bayesian inferential procedure for the noncausal vector autoregressive (VAR) model that is capable of capturing nonlinearities and incorporating effects of missing variables. In particular, we devise a fast and reliable posterior simulator that yields the predictive distribution as a by-product. We apply the methods to postwar quarterly U.S. inflation and GDP growth series. The noncausal VAR model turns out to be superior in terms of both in-sample fit and out-of-sample forecasting performance over its conventional causal counterpart. In addition, we find GDP growth to have predictive power for the future distribution of inflation over and above the own history of inflation, but not vice versa. This may be interpreted as evidence against the new Keynesian model that implies Granger causality from inflation to GDP growth, provided GDP growth is a reasonable proxy of the marginal cost.

Lanne, Markku; Luoto, Jani

2014-01-01

337

An Update on Canine Adenovirus Type 2 and Its Vectors  

Directory of Open Access Journals (Sweden)

Full Text Available Adenovirus vectors have significant potential for long- or short-term gene transfer. Preclinical and clinical studies using human derived adenoviruses (HAd have demonstrated the feasibility of flexible hybrid vector designs, robust expression and induction of protective immunity. However, clinical use of HAd vectors can, under some conditions, be limited by pre-existing vector immunity. Pre-existing humoral and cellular anti-capsid immunity limits the efficacy and duration of transgene expression and is poorly circumvented by injections of larger doses and immuno-suppressing drugs. This review updates canine adenovirus serotype 2 (CAV-2, also known as CAdV-2 biology and gives an overview of the generation of early region 1 (E1-deleted to helper-dependent (HD CAV-2 vectors. We also summarize the essential characteristics concerning their interaction with the anti-HAd memory immune responses in humans, the preferential transduction of neurons, and its high level of retrograde axonal transport in the central and peripheral nervous system. CAV-2 vectors are particularly interesting tools to study the pathophysiology and potential treatment of neurodegenerative diseases, as anti-tumoral and anti-viral vaccines, tracer of synaptic junctions, oncolytic virus and as a platform to generate chimeric vectors.

Eric J. Kremer

2010-09-01

338

Mobilization and Mechanism of Transcription of Integrated Self-Inactivating Lentiviral Vectors  

Science.gov (United States)

Permanent genetic modification of replicating primitive hematopoietic cells by an integrated vector has many potential therapeutic applications. Both oncoretroviral and lentiviral vectors have a predilection for integration into transcriptionally active genes, creating the potential for promoter activation or gene disruption. The use of self-inactivating (SIN) vectors in which a deletion of the enhancer and promoter sequences from the 3? long terminal repeat (LTR) is copied over into the 5? LTR during vector integration is designed to improve safety by reducing the risk of mobilization of the vector genome and the influence of the LTR on nearby cellular promoters. Our results indicate that SIN vectors are mobilized in cells expressing lentiviral proteins, with the frequency of mobilization influenced by features of the vector design. The mechanism of transcription of integrated vector genomes was evaluated using a promoter trap design with a vector encoding tat but lacking an upstream promoter in a cell line in which drug resistance depended on tat expression. In six clones studied, all transcripts originated from cryptic promoters either upstream or within the vector genome. We estimate that approximately 1 in 3,000 integrated vector genomes is transcribed, leading to the inference that activation of cryptic promoters must depend on local features of chromatin structure and the constellation of nearby regulatory elements as well as the nature of the regulatory elements within the vector. PMID:15956585

Hanawa, Hideki; Persons, Derek A.; Nienhuis, Arthur W.

2005-01-01

339

Vectors on the Basketball Court  

Science.gov (United States)

An Idea Bank published in the April/May 2009 issue of "The Science Teacher" describes an experiential physics lesson on vectors and vector addition (Brown 2009). Like its football predecessor, the basketball-based investigation presented in this Idea Bank addresses National Science Education Standards Content B, Physical Science, 9-12 (NRC 1996)…

Bergman, Daniel

2010-01-01

340

Estimation of Motion Vector Fields  

DEFF Research Database (Denmark)

This paper presents an approach to the estimation of 2-D motion vector fields from time varying image sequences. We use a piecewise smooth model based on coupled vector/binary Markov random fields. We find the maximum a posteriori solution by simulated annealing. The algorithm generate sample fields by means of stochastic relaxation implemented via the Gibbs sampler.

Larsen, Rasmus

1993-01-01

 
 
 
 
341

Science of NFL Football: Vectors  

Science.gov (United States)

NBC's Lester Holt looks at the role vectors play every time an NFL quarterback throws a pass. With the help of former NFL quarterback Joey Harrington, NSF-funded scientist John Ziegert of Clemson University and NSF-funded mathematician Rhonda Hughes of Bryn Mawr College explain how to use vectors to calculate the speed and direction needed for a completed pass.

Learn, Nbc

2010-10-07

342

Collapse of the State Vector  

CERN Document Server

Modifications of quantum mechanics are considered, in which the state vector of any system, large or small, undergoes a stochastic evolution. The general class of theories is described, in which the probability distribution of the state vector collapses to a sum of delta functions, one for each possible final state, with coefficients given by the Born rule.

Weinberg, Steven

2011-01-01

343

Comparison of the vector potential of different mosquito species for the transmission of heartworm, Dirofilaria immitis, in rural and urban areas in and surrounding Stillwater, Oklahoma, U.S.A.  

Science.gov (United States)

Dirofilaria immitis Leidy (Spirurida: Onchocercidae), or heartworm, is a mosquito-borne nematode that causes a fatal disease in carnivores. Although infection is preventable through prophylactic drugs, compliance and the spectre of resistance suggest vector control is a viable alternative. There were two main objectives in this study: (a) to evaluate the relationships between landscape and social factors and the number and species of heartworm-positive mosquitoes, with a specific focus on the importance of the invasive Asian tiger mosquito, Aedes albopictus (Skuse) (Stegomyia albopicta) (Diptera: Culicidae), and (b) to test the hypothesis that dog heartworm is more prevalent in suburban than in rural areas. To achieve these objectives, mosquitoes were collected from May to November 2010 at 16 rural and 16 urban locations in Payne County, Oklahoma, U.S.A. using three trapping methods that utilized, respectively, resting boxes, carbon dioxide traps and BG Sentinel traps. Urban areas showed greater numbers of Ae.?albopictus and a higher overall likelihood of infection with D.?immitis. Because many species of mosquito are responsible for heartworm transmission, current prophylactic treatment remains the best method of controlling this parasite. PMID:24898348

Paras, K L; O'Brien, V A; Reiskind, M H

2014-08-01

344

Canine vector-borne diseases in Brazil  

Directory of Open Access Journals (Sweden)

Full Text Available 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 ticks, fleas, lice, triatomines, mosquitoes, tabanids, and phlebotomine sand flies. This article focuses on several aspects (etiology, transmission, distribution, prevalence, risk factors, diagnosis, control, prevention, and public health significance of CVBDs in Brazil and discusses research gaps to be addressed in future studies.

Dantas-Torres Filipe

2008-08-01

345

Canine vector-borne diseases in Brazil.  

Science.gov (United States)

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 ticks, fleas, lice, triatomines, mosquitoes, tabanids, and phlebotomine sand flies. This article focuses on several aspects (etiology, transmission, distribution, prevalence, risk factors, diagnosis, control, prevention, and public health significance) of CVBDs in Brazil and discusses research gaps to be addressed in future studies. PMID:18691408

Dantas-Torres, Filipe

2008-01-01

346

Almost purity for overconvergent Witt vectors  

DEFF Research Database (Denmark)

In a previous paper, we stated a general almost purity theorem in the style of Faltings: if R is a ring for which the Frobenius maps on finite p-typical Witt vectors over R are surjective, then the integral closure of R in a finite etale extension of R[1/p] is “almost” finite etale over R. Here, we use almost purity to lift the finite ?etale extension of R[1/p] to a finite etale extension of rings of overconvergent Witt vectors. The point is that no hypothesis of p-adic completeness is needed; this result thus points towards potential global analogues of p-adic Hodge theory. As an illustration, we construct (?,?)-modules associated to Artin Motives over Q. The (?, ?)-modules we construct are defined over a base ring which seems well-suited to generalization to a more global setting; we plan to pursue such generalizations in later work.

Davis, Christopher James; Kedlaya, Kiran

2014-01-01

347

Semismooth support vector machines.  

Energy Technology Data Exchange (ETDEWEB)

The linear support vector machine can be posed as a quadratic program in a variety of ways. In this paper, we look at a formulation using the two-norm for the misclassification error that leads to a positive definite quadratic program with a single equality constraint when the Wolfe dual is taken. The quadratic term is a small rank update to a positive definite matrix. We reformulate the optimality conditions as a semismooth system of equations using the Fischer-Burmeister function and apply a damped Newton method to solve the resulting problem. The algorithm is shown to converge from any starting point with a Q-quadratic rate of convergence. At each iteration, we use the Sherman-Morrison-Woodbury update formula to solve a single linear system of equations. Significant computational savings are realized as the inactive variables are identified and exploited during the solution process. Results for a 60 million variable problem are presented, demonstrating the effectiveness of the proposed method on a personal computer.

Ferris, M. C.; Munson, T. S.; Mathematics and Computer Science; Univ. of Wisconsin

2004-09-01

348

Disrupting the transmission of a vector-borne plant pathogen.  

Science.gov (United States)

Approaches to control vector-borne diseases rarely focus on the interface between vector and microbial pathogen, but strategies aimed at disrupting the interactions required for transmission may lead to reductions in disease spread. We tested if the vector transmission of the plant-pathogenic bacterium Xylella fastidiosa was affected by three groups of molecules: lectins, carbohydrates, and antibodies. Although not comprehensively characterized, it is known that X. fastidiosa adhesins bind to carbohydrates, and that these interactions are important for initial cell attachment to vectors, which is required for bacterial transmission from host to host. Lectins with affinity to substrates expected to occur on the cuticular surface of vectors colonized by X. fastidiosa, such as wheat germ agglutinin, resulted in statistically significant reductions in transmission rate, as did carbohydrates with N-acetylglucosamine residues. Presumably, lectins bound to receptors on the vector required for cell adhesion/colonization, while carbohydrate-saturated adhesins on X. fastidiosa's cell surface. Furthermore, antibodies against X. fastidiosa whole cells, gum, and afimbrial adhesins also resulted in transmission blockage. However, no treatment resulted in the complete abolishment of transmission, suggesting that this is a complex biological process. This work illustrates the potential to block the transmission of vector-borne pathogens without directly affecting either organism. PMID:22101059

Killiny, Nabil; Rashed, Arash; Almeida, Rodrigo P P

2012-02-01

349

Hygromycin-resistance vectors for gene expression in Pichia pastoris.  

Science.gov (United States)

Pichia pastoris is a common host organism for heterologous protein expression and metabolic engineering. Zeocin-, G418-, nourseothricin- and blasticidin-resistance genes are the only dominant selectable markers currently available for selecting P. pastoris transformants. We describe here new P. pastoris expression vectors that confer a hygromycin resistance base on the Klebsiella pneumoniae hph gene. To demonstrate the application of the vectors for intracellular and secreted protein expression, green fluorescent protein (GFP) and human serum albumin (HSA) were cloned into the vectors and transformed into P. pastoris cells. The resulting strains expressed GFP and HSA constitutively or inducibly. The hygromycin resistance marker was also suitable for post-transformational vector amplication (PTVA) for obtaining strains with high plasmid copy numbers. A strain with multiple copies of the HSA expression cassette after PTVA had increased HSA expression compared with a strain with a single copy of the plasmid. To demonstrate compatibility of the new vectors with other vectors bearing antibiotic-resistance genes, P. pastoris was transformed with the Saccharomyces cerevisiae genes GSH1, GSH2 or SAM2 on plasmids containing genes for resistance to Zeocin, G418 or hygromycin. The resulting strain produced glutathione and S-adenosyl-L-methionine at levels approximately twice those of the parent strain. The new hygromycin-resistance vectors allow greater flexibility and potential applications in recombinant protein production and other research using P. pastoris. PMID:24822243

Yang, Junjie; Nie, Lei; Chen, Biao; Liu, Yingmiao; Kong, Yimeng; Wang, Haibin; Diao, Liuyang

2014-04-01

350

Chiral structure of vector and axial-vector tetraquark currents  

Energy Technology Data Exchange (ETDEWEB)

We investigate the chiral structure of local vector and axial-vector tetraquark currents, and study their chiral transformation properties. We consider the charge-conjugation parity and classify all the isovector vector and axial-vector local tetraquark currents of quantum numbers I{sup G} J{sup PC} =1{sup -}1{sup -+}, I{sup G} J{sup PC} =1{sup +}1{sup --}, I{sup G} J{sup PC} = 1{sup -}1{sup ++} and I{sup G} J{sup PC} = 1{sup +}1{sup +-}. We find that there is a one to one correspondence among them. Using these currents, we perform QCD sum rule analyses. Our results suggest that there is a missing b{sub 1} state having I{sup G} J{sup PC} =1{sup +}1{sup +-} and a mass around 1.47-1.66 GeV. (orig.)

Chen, Hua-Xing [Beihang University, School of Physics and Nuclear Energy Engineering and International Research Center for Nuclei and Particles in the Cosmos, Beijing (China)

2013-11-15

351

On the Witt vector Frobenius  

DEFF Research Database (Denmark)

We study the kernel and cokernel of the Frobenius map on the p-typical Witt vectors of a commutative ring, not necessarily of characteristic p. We give many equivalent conditions to surjectivity of the Frobenius map on both finite and infinite length Witt vectors. In particular, surjectivity on finite Witt vectors turns out to be stable under certain integral extensions; this provides a clean formulation of a strong generalization of Faltings’s almost purity theorem from p-adic Hodge theory, incorporating recent improvements by Kedlaya–Liu and by Scholze.

Davis, Christopher James; Kedlaya, Kiran

2014-01-01

352

Idea Bank: Vector, Vector--That's Our Cry!  

Science.gov (United States)

There are all kinds of computer-based software programs and websites available to help students understand and manipulate vector quantities. But if you have the time and want to do something different, this Idea Bank describes an easy, low-tech, and fun activity for teaching the "head-to-tail" method of combining vectors and the difference between "distance" and "displacement." All you need for this activity are scissors, some envelopes, metersticks, and a football field.

Brown, Jeremy

2009-04-01

353

Evaluation of leading scalar and vector architectures for scientific computations  

Energy Technology Data Exchange (ETDEWEB)

The growing gap between sustained and peak performance for scientific applications is a well-known problem in high performance computing. The recent development of parallel vector systems offers the potential to reduce this gap for many computational science codes and deliver a substantial increase in computing capabilities. This project examines the performance of the cacheless vector Earth Simulator (ES) and compares it to superscalar cache-based IBM Power3 system. Results demonstrate that the ES is significantly faster than the Power3 architecture, highlighting the tremendous potential advantage of the ES for numerical simulation. However, vectorization of a particle-in-cell application (GTC) greatly increased the memory footprint preventing loop-level parallelism and limiting scalability potential.

Simon, Horst D.; Oliker, Leonid; Canning, Andrew; Carter, Jonathan; Ethier, Stephane; Shalf, John

2004-04-20

354

Understanding Polarization Correlation of Entangled Vector Meson Pairs  

CERN Document Server

Quantum mechanics (QM) disfavours local realism because it violates Bell's theorem, a theorem that must be valid for all local hidden variable theories (LHVT). Experimental tests of local realism in high energy particle physics have been proposed and carried out, but no decisive conclusion has been drawn. We find that the correlated distribution between polarization vectors of two entangled mesons predicted by QM can be reproduced in a natural way, by interpreting the two-body decay of vector mesons as a measurement to their polarization vector. The interpretation provides a method to simulate the correlated decay of entangled vector meson pairs, and a potential experimental approach for the discrimination between QM and LHVT in particle physics. Related data analysis can be carried out at currently running experiments and could give deeper insight for the understanding of local realism.

Chen, Xun; Mao, Yajun

2012-01-01

355

The vector wave equation in de Sitter space-time  

CERN Document Server

The vector wave equation, supplemented by the Lorenz gauge condition, is decoupled and solved exactly in de Sitter space-time studied in static spherical coordinates. One component of the vector field is expressed, in its radial part, through the solution of a fourth-order ordinary differential equation obeying given initial conditions. The other components of the vector field are then found by acting with lower-order differential operators on the solution of the fourth-order equation (while the transverse part is decoupled and solved exactly from the beginning). The whole four-vector potential is eventually expressed through hypergeometric functions and spherical harmonics. Its radial part is plotted for given choices of initial conditions. This is an important step towards solving exactly the tensor wave equation in de Sitter space-time, which has important applications to the theory of gravitational waves about curved backgrounds.

Bini, Donato; Montaquila, Roberto Valentino

2008-01-01

356

Circadian rhythms in insect disease vectors  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Organisms from bacteria to humans have evolved under predictable daily environmental cycles owing to the Earth’s rotation. This strong selection pressure has generated endogenous circadian clocks that regulate many aspects of behaviour, physiology and metabolism, anticipating and synchronising inter [...] nal time-keeping to changes in the cyclical environment. In haematophagous insect vectors the circadian clock coordinates feeding activity, which is important for the dynamics of pathogen transmission. We have recently witnessed a substantial advance in molecular studies of circadian clocks in insect vector species that has consolidated behavioural data collected over many years, which provided insights into the regulation of the clock in the wild. Next generation sequencing technologies will facilitate the study of vector genomes/transcriptomes both among and within species and illuminate some of the species-specific patterns of adaptive circadian phenotypes that are observed in the field and in the laboratory. In this review we will explore these recent findings and attempt to identify potential areas for further investigation.

Antonio Carlos Alves, Meireles-Filho; Charalambos Panayiotis, Kyriacou.

357

Vector meson production at HERA  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The rich experimental landscape of exclusive vector meson production at the high energy electron-proton collider HERA is reviewed, with emphasis on the transition from soft to hard diffraction and QCD interpretations.

Marage, Pierre

2008-01-01

358

Solid rocket thrust vector control  

Science.gov (United States)

Thrust vector control systems that superimpose a side force on the motor thrust, steering being achieved by the side force causing a moment about the vehicle center of gravity are described. A brief review of thrust vector control systems is presented, and two systems, flexible joint and liquid injection, are treated in detail. Treatment of the flexible-joint thrust vector control system is limited to the design of the flexible joint and its insulation against hot motor gases. Treatment of the liquid injection thrust vector control system is limited to discussion of the injectant, valves, piping, storage tanks, and pressurization system; no evaluation is presented of the nozzle except for (1) the effect of the injectant and erosion at the injection port and (2) the effect of injection on pressure distribution within the nozzle.

1974-01-01

359

Vector triplets at the LHC  

CERN Document Server

Several popular extensions of the Standard Model predict extra vector fields that transform as triplets under the gauge group SU(2)_L. These multiplets contain Z' and W' bosons, with masses and couplings related by gauge invariance. We review some model-independent results about these new vector bosons, with emphasis on di-lepton and lepton-plus-missing-energy signals at the LHC.

Lizana, J M

2013-01-01

360

An exotic composite vector boson  

International Nuclear Information System (INIS)

An exotic composite vector boson, V, is introduced in two dynamical models of composite quarks, leptons, W and Z. One is based on four Fermi interactions, in which composite vector bosons are regarded as fermion-antifermion bound states and the other is based on the confining SU(2)L gauge model, in which they are given by scalar-antiscalar bound states. Both approaches describe the same effective interactions for the sector of composite quarks, leptons, W, Z, ? and V. (author)

 
 
 
 
361

Adaptive neural network vector predictor  

Science.gov (United States)

In this paper, an adaptive neural network vector predictor is designed in order to improve the performance of the predictive component of the predictive vector quantizer (PVQ). The proposed vector predictor consists of a set of dedicated predictors (experts) where each predictor is optimized for a particular class of input vectors. In our simulations, we used five multi-layer perceptrons (MLP) to design our expert predictors. Each MLP predictor is separately trained by using a set of training vectors that belong to a particular class. The class identity of each training vector is determined by its directional variances. In our current implementation, one predictor is optimized for stationary blocks and four other predictors are designed for horizontal, vertical, 45 degree and 135 degree diagonally oriented edge blocks. The back-propagation algorithm is used for training each network. The directional variances of the neighboring blocks are used to select the appropriate expert predictor for the current input block. Therefore, no overhead information is transmitted in order to inform the receiver about the predictor selection. Our simulation shows that the proposed scheme gives an improvement of more than 1 dB over the predictor consisting of a single MLP predictor. The perceptual quality of the predicted images are also significantly improved.

Wang, Lin-Cheng; Rizvi, Syed A.; Nasrabadi, Nasser M.; Mirelli, Vincent

1996-03-01

362

VectorBase: a home for invertebrate vectors of human pathogens  

Digital Repository Infrastructure Vision for European Research (DRIVER)

VectorBase () is a web-accessible data repository for information about invertebrate vectors of human pathogens. VectorBase annotates and maintains vector genomes providing an integrated resource for the research community. Currently, VectorBase contains genome information for two organisms: Anopheles gambiae, a vector for the Plasmodium protozoan agent causing malaria, and Aedes aegypti, a vector for the flaviviral agents causing Yellow fever and Dengue fever.

Lawson, Daniel; Arensburger, Peter; Atkinson, Peter; Besansky, Nora J.; Bruggner, Robert V.; Butler, Ryan; Campbell, Kathryn S.; Christophides, George K.; Christley, Scott; Dialynas, Emmanuel; Emmert, David; Hammond, Martin; Hill, Catherine A.; Kennedy, Ryan C.; Lobo, Neil F.

2007-01-01

363

Máquinas de vectores de soporte / Boosting Support Vector Machines  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish En este articulo, se presenta un algoritmo de clasificacion binaria basado en Support Vector Machines (Maquinas de Vectores de Soporte) que combinado apropiadamente con tecnicas de Boosting consigue un mejor desempeno en cuanto a tiempo de entrenamiento y conserva caracteristicas similares de genera [...] lizacion con un modelo de igual complejidad pero de representacion mas compacta. Abstract in english In this paper we present an algorithm of binary classification based on Support Vector Machines. It is combined with a modified Boosting algorithm. It run faster than the original SVM algorithm with a similar generalization error and equal complexity model but it has more compact representation. [...

Elkin Eduardo, García Díaz; Fernando, Lozano Martínez.

2006-11-01

364

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

Science.gov (United States)

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-based vectors for gene delivery purposes has been studied over the past years. In this review, the key achievements and functional evaluation of the existing vectors from in vitro cell culture systems to out-bred cats will be described. The data presented here demonstrate the broad application spectrum of FFV-based vectors, especially in pathogen-specific prophylactic and therapeutic vaccination using RD vectors in cats and in classical gene delivery. In the cat-based system, FFV-based vectors provide an advantageous platform to evaluate and optimize the applicability, efficacy and safety of foamy virus (FV) vectors, especially the understudied aspect of FV cell and organ tropism. PMID:23857307

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

2013-01-01

365

Vector competence of selected North American Culex and Coquillettidia mosquitoes for West Nile virus.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To control West Nile virus (WNV), it is necessary to know which mosquitoes are able to transmit this virus. Therefore, we evaluated the WNV vector potential of several North American mosquito species. Culex restuans and Cx. salinarius, two species from which WNV was isolated in New York in 2000, were efficient laboratory vectors. Cx. quinquefasciatus and Cx. nigripalpus from Florida were competent but only moderately efficient vectors. Coquillettidia perturbans was an inefficient laboratory v...

Sardelis, M. R.; Turell, M. J.; Dohm, D. J.; O Guinn, M. L.

2001-01-01

366

Absence of Klein's paradox for massive bosons coupled by nonminimal vector interactions  

CERN Document Server

A few properties of the nonminimal vector interactions in the Duffin-Kemmer-Petiau theory are revised. In particular, it is shown that the space component of the nonminimal vector interaction plays a peremptory role for confining bosons whereas its time component contributes to the leakage. Scattering in a square step potential with proper boundary conditions is used to show that Klein's paradox does not manifest in the case of a nonminimal vector coupling.

Cardoso, T R; De Castro, A S

2009-01-01

367

Implementing Bayesian Vector Autoregressions Implementing Bayesian Vector Autoregressions  

Directory of Open Access Journals (Sweden)

Full Text Available Implementing Bayesian Vector Autoregressions This paper discusses how the Bayesian approach can be used to construct a type of multivariate forecasting model known as a Bayesian vector autoregression (BVAR. In doing so, we mainly explain Doan, Littermann, and Sims (1984 propositions on how to estimate a BVAR based on a certain family of prior probability distributions. indexed by a fairly small set of hyperparameters. There is also a discussion on how to specify a BVAR and set up a BVAR database. A 4-variable model is used to iliustrate the BVAR approach.

Richard M. Todd

1988-03-01

368

Hybrid biosynthetic gene therapy vector development and dual engineering capacity.  

Science.gov (United States)

Genetic vaccines offer a treatment opportunity based upon successful gene delivery to specific immune cell modulators. Driving the process is the vector chosen for gene cargo packaging and subsequent delivery to antigen-presenting cells (APCs) capable of triggering an immune cascade. As such, the delivery process must successfully navigate a series of requirements and obstacles associated with the chosen vector and target cell. In this work, we present the development and assessment of a hybrid gene delivery vector containing biological and biomaterial components. Each component was chosen to design and engineer gene delivery separately in a complimentary and fundamentally distinct fashion. A bacterial (Escherichia coli) inner core and a biomaterial [poly(beta-amino ester)]-coated outer surface allowed the simultaneous application of molecular biology and polymer chemistry to address barriers associated with APC gene delivery, which include cellular uptake and internalization, phagosomal escape, and intracellular cargo concentration. The approach combined and synergized normally disparate vector properties and tools, resulting in increased in vitro gene delivery beyond individual vector components or commercially available transfection agents. Furthermore, the hybrid device demonstrated a strong, efficient, and safe in vivo humoral immune response compared with traditional forms of antigen delivery. In summary, the flexibility, diversity, and potential of the hybrid design were developed and featured in this work as a platform for multivariate engineering at the vector and cellular scales for new applications in gene delivery immunotherapy. PMID:25114239

Jones, Charles H; Ravikrishnan, Anitha; Chen, Mingfu; Reddinger, Ryan; Kamal Ahmadi, Mahmoud; Rane, Snehal; Hakansson, Anders P; Pfeifer, Blaine A

2014-08-26

369

Hybrid biosynthetic gene therapy vector development and dual engineering capacity  

Science.gov (United States)

Genetic vaccines offer a treatment opportunity based upon successful gene delivery to specific immune cell modulators. Driving the process is the vector chosen for gene cargo packaging and subsequent delivery to antigen-presenting cells (APCs) capable of triggering an immune cascade. As such, the delivery process must successfully navigate a series of requirements and obstacles associated with the chosen vector and target cell. In this work, we present the development and assessment of a hybrid gene delivery vector containing biological and biomaterial components. Each component was chosen to design and engineer gene delivery separately in a complimentary and fundamentally distinct fashion. A bacterial (Escherichia coli) inner core and a biomaterial [poly(beta-amino ester)]-coated outer surface allowed the simultaneous application of molecular biology and polymer chemistry to address barriers associated with APC gene delivery, which include cellular uptake and internalization, phagosomal escape, and intracellular cargo concentration. The approach combined and synergized normally disparate vector properties and tools, resulting in increased in vitro gene delivery beyond individual vector components or commercially available transfection agents. Furthermore, the hybrid device demonstrated a strong, efficient, and safe in vivo humoral immune response compared with traditional forms of antigen delivery. In summary, the flexibility, diversity, and potential of the hybrid design were developed and featured in this work as a platform for multivariate engineering at the vector and cellular scales for new applications in gene delivery immunotherapy. PMID:25114239

Jones, Charles H.; Ravikrishnan, Anitha; Chen, Mingfu; Reddinger, Ryan; Kamal Ahmadi, Mahmoud; Rane, Snehal; Hakansson, Anders P.; Pfeifer, Blaine A.

2014-01-01

370

Generalized Selection Weighted Vector Filters  

Directory of Open Access Journals (Sweden)

Full Text Available This paper introduces a class of nonlinear multichannel filters capable of removing impulsive noise in color images. The here-proposed generalized selection weighted vector filter class constitutes a powerful filtering framework for multichannel signal processing. Previously defined multichannel filters such as vector median filter, basic vector directional filter, directional-distance filter, weighted vector median filters, and weighted vector directional filters are treated from a global viewpoint using the proposed framework. Robust order-statistic concepts and increased degree of freedom in filter design make the proposed method attractive for a variety of applications. Introduced multichannel sigmoidal adaptation of the filter parameters and its modifications allow to accommodate the filter parameters to varying signal and noise statistics. Simulation studies reported in this paper indicate that the proposed filter class is computationally attractive, yields excellent performance, and is able to preserve fine details and color information while efficiently suppressing impulsive noise. This paper is an extended version of the paper by Lukac et al. presented at the 2003 IEEE-EURASIP Workshop on Nonlinear Signal and Image Processing (NSIP '03 in Grado, Italy.

Rastislav Lukac

2004-09-01

371

Vector-Quantization using Information Theoretic Concepts  

DEFF Research Database (Denmark)

The process of representing a large data set with a smaller number of vectors in the best possible way, also known as vector quantization, has been intensively studied in the recent years. Very efficient algorithms like the Kohonen Self Organizing Map (SOM) and the Linde Buzo Gray (LBG) algorithm have been devised. In this paper a physical approach to the problem is taken, and it is shown that by considering the processing elements as points moving in a potential field an algorithm equally efficient as the before mentioned can be derived. Unlike SOM and LBG this algorithm has a clear physical interpretation and relies on minimization of a well defined cost-function. It is also shown how the potential field approach can be linked to information theory by use of the Parzen density estimator. In the light of information theory it becomes clear that minimizing the free energy of the system is in fact equivalent to minimizing a divergence measure between the distribution of the data and the distribution of the processing element, hence, the algorithm can be seen as a density matching method.

Lehn-SchiØler, Tue

2005-01-01

372

Viral vectors, in innate and adaptive immunity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recombinant viral vectors and DNA vectors induce strong immune responses in animal models. However, in clinical trials, the generation of immune responses is less robust, suggesting that further optimization and a deeper understanding of nucleic acid-based vaccines are required. Improvements, such as combining the vaccine vectors in heterologous prime boost regimens and/or using vectors that do not induce strong immune responses against the vector itself may enhance immune r...

Na?slund, Tanja I.

2009-01-01

373

Generation of helper-dependent adenoviral vectors by homologous recombination.  

Science.gov (United States)

Helper-dependent adenoviral vectors (HD-Ad) represent a potentially valuable tool for safe and prolonged gene expression in vivo. The current approach for generating these vectors is based on ligation of the expression cassette into large plasmids containing the viral inverted terminal repeats flanking "stuffer" DNA to maintain a final size above the lower limit for efficient packaging into the adenovirus capsid (approximately 28 kb). The ligation to produce the viral plasmid is generally very inefficient. Similar problems in producing first-generation adenoviral (FG-Ad) vectors were circumvented with the development of a system taking advantage of efficient homologous recombination between a shuttle plasmid containing the expression cassette and a FG-Ad vector backbone in the Escherichia coli strain BJ5183. Here we describe a method for fast and efficient generation of HD-Ad vector plasmids that can accommodate expression cassettes of any size up to 35 kb. To validate the system, we generated a HD-Ad vector expressing the fusion protein between beta-galactosidase and neomycin resistance genes under the control of the SR alpha promoter, and one expressing the enhanced green fluorescent protein under the control of the cytomegalovirus promoter. The viruses were rescued and tested in vitro and for in vivo expression in mice. The data collected indicate the possibility for achieving a high level of hepatocyte transduction using HD-Ad vectors derived from plasmids obtained by homologous recombination in E. coli, with no significant alteration of liver enzymes and a less severe, transient thrombocytopenia in comparison with previous reports with similar doses of a FG-Ad vector. PMID:11829528

Toietta, Gabriele; Pastore, Lucio; Cerullo, Vincenzo; Finegold, Milton; Beaudet, Arthur L; Lee, Brendan

2002-02-01

374

Immunogenicity of repeated Sendai viral vector vaccination in macaques.  

Science.gov (United States)

Induction of durable cellular immune responses by vaccination is an important strategy for the control of persistent pathogen infection. Viral vectors are promising vaccine tools for eliciting antigen-specific T-cell responses. Repeated vaccination may contribute to durable memory T-cell induction, but anti-vector antibodies could be an obstacle to its efficacy. We previously developed a Sendai virus (SeV) vector vaccine and showed the potential of this vector for efficient T-cell induction in macaques. Here, we examined whether repeated SeV vector vaccination with short intervals can enhance antigen-specific CD8(+) T-cell responses. Four rhesus macaques possessing the MHC-I haplotype 90-120-Ia were immunized three times with intervals of three weeks. For the vaccination, we used replication-defective F-deleted SeV vectors inducing CD8(+) T-cell responses specific for simian immunodeficiency virus Gag(206-216) and Gag(241-249), which are dominant epitopes restricted by 90-120-Ia-derived MHC-I molecules. All four animals showed higher Gag(206-216)-specific and Gag(241-249)-specific CD8(+) T-cell responses after the third vaccination than those after the first vaccination, indicating enhancement of antigen-specific CD8(+) T-cell responses by the second/third SeV vector vaccination even with short intervals. These results suggest that repeated SeV vector vaccination can contribute to induction of efficient and durable T-cell responses. PMID:22884717

Kurihara, Kyoko; Takahara, Yusuke; Nomura, Takushi; Ishii, Hiroshi; Iwamoto, Nami; Takahashi, Naofumi; Inoue, Makoto; Iida, Akihiro; Hara, Hiroto; Shu, Tsugumine; Hasegawa, Mamoru; Moriya, Chikaya; Matano, Tetsuro

2012-11-01

375

Skyrmions with vector mesons revisited  

CERN Document Server

In order to develop a model that can describe both a single baryon and multi-baryon systems on the same footing, we re-investigate the Skyrme model in a chiral Lagrangian derived from the hidden local symmetry (HLS) up to $O(p^4)$ including the homogeneous Wess-Zumino terms. We use the master formulas that connect the parameters of the HLS Lagrangian and a class of holographic QCD models, which provides a controllable way to determine the low-energy constants of the Lagrangian once the pion decay constant and the vector meson mass are given. Therefore, this model allows us to study the role of vector mesons in the skyrmion structure. We find that the $\\rho$ and $\\omega$ vector mesons have different roles in the skyrmion structure and that the $\\omega$ meson has an important role in the properties of the nucleon.

Oh, Yongseok

2014-01-01

376

Toward lattice fractional vector calculus  

Science.gov (United States)

An analog of fractional vector calculus for physical lattice models is suggested. We use an approach based on the models of three-dimensional lattices with long-range inter-particle interactions. The lattice analogs of fractional partial derivatives are represented by kernels of lattice long-range interactions, where the Fourier series transformations of these kernels have a power-law form with respect to wave vector components. In the continuum limit, these lattice partial derivatives give derivatives of non-integer order with respect to coordinates. In the three-dimensional description of the non-local continuum, the fractional differential operators have the form of fractional partial derivatives of the Riesz type. As examples of the applications of the suggested lattice fractional vector calculus, we give lattice models with long-range interactions for the fractional Maxwell equations of non-local continuous media and for the fractional generalization of the Mindlin and Aifantis continuum models of gradient elasticity.

Tarasov, Vasily E.

2014-09-01

377

Effective magnetic anisotropy vector field  

International Nuclear Information System (INIS)

An effective anisotropy vector field that can be treated as an effective external field has been formulated for uniaxial anisotropies with n-fold symmetry within the plane containing the main axis. A simple method for obtaining the effective field for the two-fold symmetry uniaxial anisotropy and the calculated result according to the method are presented. Then the extension to n-fold symmetry anisotropies is given and the calculated results for four- and six-fold symmetry cases are demonstrated. The tips of those vector fields are found to trace hypocycloids moving oppositely with the rotation of magnetization. The newly introduced effective anisotropy vector field may make a new tool in various analysis of magnetization processes and help understand the effect of anisotropy on magnetization visually

378

Learning with Support Vector Machines  

CERN Document Server

Support Vectors Machines have become a well established tool within machine learning. They work well in practice and have now been used across a wide range of applications from recognizing hand-written digits, to face identification, text categorisation, bioinformatics, and database marketing. In this book we give an introductory overview of this subject. We start with a simple Support Vector Machine for performing binary classification before considering multi-class classification and learning in the presence of noise. We show that this framework can be extended to many other scenarios such a

Campbell, Colin

2010-01-01

379

Radiative decay of vector mesons  

International Nuclear Information System (INIS)

Radiative decay of mesons is an important aspect in low-energy hadronic physics, through which structures and properties of mesons can be revealed.In view of effective field theories, the radiative decay of mesons involves mainly interactions between photons and hadrons. In this paper, we investigate the decay of vector mesons by using SU(3)symmetry and the vector meson dominance model respectively. By fitting with experiments, we give the theoretic widths for V?P? in both cases and the mixing angle of pseudoscalars ?P is-6 degree. (authors)

380

Requirements for airborne vector gravimetry  

Science.gov (United States)

The objective of airborne vector gravimetry is the determination of the full gravity disturbance vector along the aircraft trajectory. The paper briefly outlines the concept of this method using a combination of inertial and GPS-satellite data. The accuracy requirements for users in geodesy and solid earth geophysics, oceanography and exploration geophysics are then specified. Using these requirements, accuracy specifications for the GPS subsystem and the INS subsystem are developed. The integration of the subsystems and the problems connected with it are briefly discussed and operational methods are indicated that might reduce some of the stringent accuracy requirements.

Schwarz, K. P.; Colombo, O.; Hein, G.; Knickmeyer, E. T.

1992-01-01

 
 
 
 
381

Comparative seroprevalence and immunogenicity of six rare serotype recombinant adenovirus vaccine vectors from subgroups B and D.  

Science.gov (United States)

Recombinant adenovirus serotype 5 (rAd5) vector-based vaccines are currently being developed for both human immunodeficiency virus type 1 and other pathogens. The potential limitations associated with rAd5 vectors, however, have led to the construction of novel rAd vectors derived from rare Ad serotypes. Several rare serotype rAd vectors have already been described, but a detailed comparison of multiple rAd vectors from subgroups B and D has not previously been reported. Such a comparison is critical for selecting optimal rAd vectors for advancement into clinical trials. Here we describe the construction of three novel rAd vector systems from Ad26, Ad48, and Ad50. We report comparative seroprevalence and immunogenicity studies involving rAd11, rAd35, and rAd50 vectors from subgroup B; rAd26, rAd48, and rAd49 vectors from subgroup D; and rAd5 vectors from subgroup C. All six rAd vectors from subgroups B and D exhibited low seroprevalence in a cohort of 200 individuals from sub-Saharan Africa, and they elicited Gag-specific cellular immune responses in mice both with and without preexisting anti-Ad5 immunity. The rAd vectors from subgroup D were also evaluated using rhesus monkeys and were shown to be immunogenic after a single injection. The rAd26 vectors proved the most immunogenic among the rare serotype rAd vectors studied, although all rare serotype rAd vectors were still less potent than rAd5 vectors in the absence of anti-Ad5 immunity. These studies substantially expand the portfolio of rare serotype rAd vectors that may prove useful as vaccine vectors for the developing world. PMID:17329340

Abbink, Peter; Lemckert, Angelique A C; Ewald, Bonnie A; Lynch, Diana M; Denholtz, Matthew; Smits, Shirley; Holterman, Lennart; Damen, Irma; Vogels, Ronald; Thorner, Anna R; O'Brien, Kara L; Carville, Angela; Mansfield, Keith G; Goudsmit, Jaap; Havenga, Menzo J E; Barouch, Dan H

2007-05-01

382

Landau levels in a 2D noncommutative space: matrix and quaternionic vector coherent states  

CERN Document Server

The behavior of an electron in an external uniform electromagnetic background coupled to a harmonic potential, with noncommuting space coordinates, is considered in this work. The thermodynamics of the system is studied. Matrix vector coherent states (MVCS) as well as quaternionic vector coherent states (QVCS), satisfying required properties, are also constructed and discussed.

Hounkonnou, M N

2012-01-01

383

Testing Studentsâ Understanding of Vector Concepts  

Science.gov (United States)

After four years of research we designed a 20-item multiple choice vector concept test (Test of Understanding of Vectors, TUV). In this article we analyze: 1) the reliability and discriminatory power of the test, and 2) studentsâ understanding of the vector concepts evaluated in the test. The final version of the test was administered in English to 423 students who were finishing an Electricity and Magnetism course at a large private Mexican university. In the first part of the article, we show results indicating that the TUV is a reliable assessment tool. In the second part, we examine studentsâ overall performance on the test and analyze the results of the five most difficult items for students: geometric interpretation of dot product, calculation of dot product of two vectors written in unit-vector notation, graphic representation of a unit vector, calculation of the direction of a vector written in unit-vector notation, and graphical subtraction of vector in 2D.

Barniol, Pablo; Zavala, Genaro

2013-12-21

384

Experiences In Comprehensive Vector Control In Indonesia  

Directory of Open Access Journals (Sweden)

Full Text Available The vector control program has been implemented in Indonesia for many years, however, vector-borne diseases are presently still a problem in Indonesia. Past activities for vector control implemented indoor residual spraying and larviciding only. Vector control problems occur through many causes and this has complicated past control programs. Presently, these complicated causes are surveyed thoroughly and analyzed as a whole and a holistic approach implemented. Comprehensive vector control is determined to solve the vector control problem. In 1991, a study was conducted to introduce the Malaria Surveillance Program in Indonesia. This program uses the comprehensive and integrated approach for malaria control in general, and vector control in particular. This paper describes the vector control program in general and how comprehensive vector control is integrated into the system. It also describes the experiences obtained in Indonesia and its impact on malaria in various places in Indonesia.

Sustriayu Nalim

2012-09-01

385

Finite elements in vector lattices  

CERN Document Server

The book is the first systematical treatment of the theory of finite elements in Archimedean vector lattices and contains the results known on this topic up to the year 2013.It joins all importantcontributions achieved by a series of mathematicians that can only be found in scattered in literature.

Weber, Martin R

2014-01-01

386

Vector meson electromagnetic form factors  

CERN Document Server

The charge, magnetic and quadrupole form factors of vector mesons and the charge form factor of pseudo-scalar mesons are calculated in quenched lattice QCD. The charge radii and magnetic moments are derived. The quark sector contributions to the form factors are calculated separately and we highlight the environmental sensitivity of the light-quark contribution to charge radii.

Lasscock, B G; Leinweber, D B; Williams, A G

2006-01-01

387

Portfolio Analysis for Vector Calculus  

Science.gov (United States)

Classic stock portfolio analysis provides an applied context for Lagrange multipliers that undergraduate students appreciate. Although modern methods of portfolio analysis are beyond the scope of vector calculus, classic methods reinforce the utility of this material. This paper discusses how to introduce classic stock portfolio analysis in a…

Kaplan, Samuel R.

2015-01-01

388

Hydrogen as an energy vector  

Science.gov (United States)

The feasibility of utilizing hydrogen as an energy vector is considered, with special attention given to means of hydrogen production. The state-of-the-art in thermochemical processes is reviewed, and criteria for the technical and economic feasibility of large-scale thermochemical water splitting processes are presented. The production of hydrogen from coal and from photolysis of water is discussed.

Powers, W. D.

1975-01-01

389

Distribution amplitudes of vector mesons  

Energy Technology Data Exchange (ETDEWEB)

Results are presented for the lowest moment of the distribution amplitude for the K{sup *} vector meson. Both longitudinal and transverse moments are investigated. We use two flavours of O(a) improved Wilson fermions, together with a non-perturbative renormalisation of the matrix element. (orig.)

Braun, V.M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Broemmel, D. [Deutsches Elektronen-Synchrotron, Hamburg (Germany); Goeckeler, M. [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)

2007-11-15

390

Transfer Entropy on Rank Vectors  

CERN Document Server

Transfer entropy (TE) is a popular measure of information flow found to perform consistently well in different settings. Symbolic transfer entropy (STE) is defined similarly to TE but on the ranks of the components of the reconstructed vectors rather than the reconstructed vectors themselves. First, we correct STE by forming the ranks for the future samples of the response system with regard to the current reconstructed vector. We give the grounds for this modified version of STE, which we call Transfer Entropy on Rank Vectors (TERV). Then we propose to use more than one step ahead in the formation of the future of the response in order to capture the information flow from the driving system over a longer time horizon. To assess the performance of STE, TE and TERV in detecting correctly the information flow we use receiver operating characteristic (ROC) curves formed by the measure values in the two coupling directions computed on a number of realizations of known weakly coupled systems. We also consider diff...

Kugiumtzis, Dimitris

2010-01-01

391

Vector-meson dominance revisited  

Directory of Open Access Journals (Sweden)

Full Text Available The interaction of mesons with electromagnetism is often well described by the concept of vector-meson dominance (VMD. However, there are also examples where VMD fails. A simple chiral Lagrangian for pions, rho and omega mesons is presented which can account for the respective agreement and disagreement between VMD and phenomenology in the sector of light mesons.

Terschlüsen Carla

2012-12-01

392

Time-dependent vector stabilization  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents necessary and sufficient conditions for a single input system defined by a time-dependent vector to be stabilized by a linear feedback. The paper employs a new technique based on averaging along a moving time interval.

Sergey Nikitin

2006-08-01

393

Some properties of vector gluonium  

International Nuclear Information System (INIS)

Strong radiative transitions between levels of gluonio bound states are considered. The probability of the vector gluonium decay into Z boson and a gluon is calculated. Possible observation of this state is studied in the mode Z boson and a gluon jet

394

Transcriptomics and disease vector control  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Next-generation sequencing can be used to compare transcriptomes under different conditions. A study in BMC Genomics applies this approach to investigating the effects of exposure to a range of xenobiotics on changes in gene expression in the larvae of Aedes aegypti, the mosquito vector of dengue fever. See research article http://www.biomedcentral.com/1471-2164/11/216

Ranson Hilary; Vontas John; Alphey Luke

2010-01-01

395

Vector-valued fuzzy multifunctions  

Directory of Open Access Journals (Sweden)

Full Text Available Some of the properties of vector-valued fuzzy multifunctions are studied. The notion of sum fuzzy multifunction, convex hull fuzzy multifunction, close convex hull fuzzy multifunction, and upper demicontinuous are given, and some of the properties of these fuzzy multifunctions are investigated.

Ismat Beg

2001-01-01

396

Toroidally symmetric polynomial multiple solutions of the Vector Laplace equation  

International Nuclear Information System (INIS)

A coherent method is given for generating to arbitrary order, the toroidally symmetric, polynomial multipole solutions of the vector Laplace (Grad-Shafranov operator) equation. In a source-free region, the toroidal component toroidally symmetric magnetic vector potential may be conveniently expanded in terms of these multipoles which at large aspect ratio reduce to the simple cylindrical form (X + iZ)/sup m/. The set of multipoles considered in previous work is shown to be incomplete and additional ones are derived which partially resolve this difficulty. The expansion technique is criticized, and several practical examples are given

397

On the effect of curved streamlines on the accuracy of PIV vector fields  

Science.gov (United States)

This article derives a method to estimate and correct the bias error of the shift vector's absolute length in the presence of curved streamlines. The main idea is to identify the most likely streamline with constant curvature from the second-order shift vector and its gradient. The work establishes a theoretical framework including the systematic errors of the first-order and second-order shift vector's absolute value and angle. Synthetic images of a stationary vortex are used to validate the proposed method. The curvature-correction is also applied to a synthetic flow field with non-constant curvature to demonstrate its potential for more realistic flow fields. The results reveal that second-order accurate vector fields suffer from a biased shift vector length depending on the streamline's curvature and on the shift vector length. The bias error is negligible for vector fields with a shift vector length below the streamline curvature radius. For large shift vectors or strong curvatures, the bias error can be significantly reduced with the developed method. The approach is very general and can be applied to any vector field obtained from window-correlation particle image velocimetry (PIV), single-pixel ensemble-correlation PIV, particle tracking velocimetry or optical flow methods. It also works for all 3D extensions of the techniques, such as 3D-PTV or tomographic PIV.

Scharnowski, Sven; Kähler, Christian J.

2013-01-01

398

Challenges and future perspective for dengue vector control in the Western Pacific Region  

Directory of Open Access Journals (Sweden)

Full Text Available Dengue remains a significant public health issue in the Western Pacific Region. In the absence of a vaccine, vector control is the mainstay for dengue prevention and control. In this paper we describe vector surveillance and vector control in the Western Pacific countries and areas.Vector surveillance and control strategies used by countries and areas of the Western Pacific Region vary. Vector control strategies include chemical, biological and environmental management that mainly target larval breeding sites. The use of insecticides targeting larvae and adult mosquitoes remains the mainstay of vector control programmes. Existing vector control tools have several limitations in terms of cost, delivery and long-term sustainability. However, there are several new innovative tools in the pipeline. These include Release of Insects Carrying a Dominant Lethal system and Wolbachia, an endosymbiotic bacterium, to inhibit dengue virus in the vector. In addition, the use of biological control such as larvivorous fish in combination with community participation has potential to be scaled up. Any vector control strategy should be selected based on evidence and appropriateness for the entomological and epidemiological setting and carried out in both inter-epidemic and epidemic periods. Community participation and interagency collaboration are required for effective and sustainable dengue prevention and control. Countries and areas are now moving towards integrated vector management.

Rashid Md Abdur

2011-06-01

399

Notable reduction in illegitimate integration mediated by a PPT-deleted, nonintegrating lentiviral vector.  

Science.gov (United States)

Nonintegrating lentiviral vectors present a means of reducing the risk of insertional mutagenesis in nondividing cells and enabling short-term expression of potentially hazardous gene products. However, residual, integrase-independent integration raises a concern that may limit the usefulness of this system. Here we present a novel 3' polypurine tract (PPT)-deleted lentiviral vector that demonstrates impaired integration efficiency and, when packaged into integrase-deficient particles, significantly reduced illegitimate integration. Cells transduced with PPT-deleted vectors exhibited predominantly 1-long terminal repeat (LTR) circles and a low level of linear genomes after reverse transcription (RT). Importantly, the PPT-deleted vector exhibited titers and in vitro and in vivo expression levels matching those of conventional nonintegrating lentiviral vectors. This safer nonintegrating lentiviral vector system will support emerging technologies, such as those based on transient expression of zinc-finger nucleases (ZFNs) for gene editing, as well as reprogramming factors for inducing pluripotency. PMID:21157436

Kantor, Boris; Bayer, Matthew; Ma, Hong; Samulski, Jude; Li, Chengwen; McCown, Thomas; Kafri, Tal

2011-03-01

400

Vector correlations in rotationally inelastic molecular collisions  

Energy Technology Data Exchange (ETDEWEB)

The thesis presents an analytic model that describes scalar and vector properties of molecular collisions, both field-free and in fields. The model is based on the sudden approximation and treats molecular scattering as the Fraunhofer diffraction of matter waves from the hard-core part of the interaction potential. The theory has no fitting parameters and is inherently quantum, rendering fully state- and energy-resolved scattering amplitudes and all the quantities that unfold from them in analytic form. This allows to obtain complex polarization moments inherent to quantum stereodynamics, and to account for interference and other non-classical effects. The simplicity and analyticity of the model paves a way to understanding the origin of the features observed in experiment and exact computations, such as the angular oscillations in the state-to-state differential cross sections and the polarization moments, the rotational-state dependent variation of the integral cross sections, and change of these quantities as a function of the applied field. The theory was applied to study the k - k{sup '} vector correlation (differential cross section) for the following collision systems: Ar-NO(X{sup 2}{pi}) and Ne-OCS(X{sup 1}{sigma}) in an electrostatic field, Na{sup +}-N{sub 2}(X{sup 1}{sigma}) in a laser field, and He-CaH({sup 2}{sigma}), He-O{sub 2}(X{sup 3}{sigma}), and He-OH(X{sup 2}{pi}) in a magnetic field. The model was able to reproduce the behavior of the differential cross sections and their variation with field strength. Combining the Fraunhofer model with the quantum theory of vector correlations made it possible to study three- and four-vector properties. The model results for the k-k{sup '}-j{sup '} vector correlation in Ar-NO(X{sup 2}{pi}) and He-NO(X{sup 2}{pi}) scattering were found to be in good agreement with experiment and exact computations. This allowed to demonstrate that the stereodynamics of such collisions is contained solely in the diffractive part of the scattering amplitude which is governed by a single Legendre moment characterizing the anisotropy of the hard-core part of the system's potential energy surface. The alignment moments obtained for He-OH(X{sup 2}{pi}), He-O{sub 2}(X{sup 3}{sigma}), and He-CaH(X{sup 2}{sigma}) allowed to identify the fingerprints of diffraction, which can be used to discern diffraction-driven stereodynamics in future experiments and exact computations. Analytic results for the Ne-NO(A{sup 2}{sigma}) system were found to be in good agreement with experiment and exact computations for low rotational energy transfer; the discrepancy found for higher excitation channels could be traced back to the breakdown of the sudden approximation. The model was also applied to the k-j-k{sup '} and k-j-k{sup '}-j{sup '} correlations in rotationally inelastic Ar-NO(X{sup 2}{pi}) scattering. It was shown that preparing the reagents with polarized angular momentum j makes it possible to significantly alter the collision dynamics and stereodynamics. In the final part of the thesis the analytic theory was extended to the study of multiple scattering of matter waves propagating through atomic and molecular gases. The combination of the Fraunhofer model with the semiclassical approximation to account, respectively, for the repulsive and attractive part of the potential energy surface resulted in a simple analytic formula, which agree well with experiment for the refraction of a Li beam passing through Xe gas. (orig.)

Lemeshko, Mikhail

2011-04-13

 
 
 
 
401

Vector correlations in rotationally inelastic molecular collisions  

International Nuclear Information System (INIS)

The thesis presents an analytic model that describes scalar and vector properties of molecular collisions, both field-free and in fields. The model is based on the sudden approximation and treats molecular scattering as the Fraunhofer diffraction of matter waves from the hard-core part of the interaction potential. The theory has no fitting parameters and is inherently quantum, rendering fully state- and energy-resolved scattering amplitudes and all the quantities that unfold from them in analytic form. This allows to obtain complex polarization moments inherent to quantum stereodynamics, and to account for interference and other non-classical effects. The simplicity and analyticity of the model paves a way to understanding the origin of the features observed in experiment and exact computations, such as the angular oscillations in the state-to-state differential cross sections and the polarization moments, the rotational-state dependent variation of the integral cross sections, and change of these quantities as a function of the applied field. The theory was applied to study the k - k' vector correlation (differential cross section) for the following collision systems: Ar-NO(X2?) and Ne-OCS(X1?) in an electrostatic field, Na+-N2(X1?) in a laser field, and He-CaH(2?), He-O2(X3?), and He-OH(X2?) in a magnetic field. The model was able to reproduce the behavior of the differential cross sections and their variation with field strength. Combining the Fraunhofer model with the quantum theory of vector correlations made it possible to study three- and four-vector properties. The model results for the k-k'-j' vector correlation in Ar-NO(X2?) and He-NO(X2?) scattering were found to be in good agreement with experiment and exact computations. This allowed to demonstrate that the stereodynamics of such collisions is contained solely in the diffractive part of the scattering amplitude which is governed by a single Legendre moment characterizing the anisotropy of the hard-core part of the system's potential energy surface. The alignment moments obtained for He-OH(X2?), He-O2(X3?), and He-CaH(X2?) allowed to identify the fingerprints of diffraction, which can be used to discern diffraction-driven stereodyn