WorldWideScience
1

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)

2

The major vault protein (MVP), a new multidrug resistance associated protein, is frequently expressed in multiple myeloma.  

Science.gov (United States)

The major vault protein (MVP), a ribonucleoprotein complex which mediates the transport of xenobiotic toxins, has been implicated in multidrug resistance (MDR) not mediated by p-glycoprotein (P-gp) or multidrug resistance related protein (MRP). We evaluated, via immunohistochemistry, the presence of MVP in plasma cells of myeloma patients. Among 73 patients registered with the Southwest Oncology Group (SWOG), 52 patients (74%) were positive for MVP. The presence of MVP and P-gp were significantly associated (p 5%) was significantly associated with shorter OS (log rank p-value = 0.0002). The collective work indicates that MVP protein is common and abundant in myeloma with potential relevance to therapeutic response. PMID:10439368

Rimsza, L M; Campbell, K; Dalton, W S; Salmon, S; Willcox, G; Grogan, T M

1999-07-01

3

Vector potential, electromagnetic induction and "physical meaning"  

OpenAIRE

A forgotten experiment by Andr\\'e Blondel (1914) proves, as held on the basis of theoretical arguments in a previous paper, that the time variation of the magnetic flux is not the cause of the induced $emf$: the physical agent is instead the vector potential through the term $-\\partial\\vec A/\\partial t$ (when the induced circuit is at rest). The "good electromagnetic potentials" are determined by the Lorenz condition and retarded formulas. Other pairs of potentials derived t...

Giuliani, Giuseppe

2010-01-01

4

Relativistic scattering theory with a vector potential  

International Nuclear Information System (INIS)

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

5

Spatial resolution in vector potential photoelectron microscopy  

Energy Technology Data Exchange (ETDEWEB)

The experimental spatial resolution of vector potential photoelectron microscopy is found to be much higher than expected because of the cancellation of one of the expected contributions to the point spread function. We present a new calculation of the spatial resolution with support from finite element ray tracing, and experimental results.

Browning, R. [R. Browning Consultants, 1 Barnhart Place, Shoreham, New York 11786 (United States)

2014-03-15

6

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

7

Vector potential, electromagnetic induction and 'physical meaning'  

International Nuclear Information System (INIS)

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 -?A-vector/?t (when the induced circuit is at rest). The 'good electromagnetic potentials' are determined by the Lorenz condition and retarded formulae. Other pairs of potentials derived through appropriate gauge functions are only mathematical devices for calculating the fields; they are not physically related to the sources. The physical meaning of a theoretical term relies, primarily, on theoretical grounds; a theoretical term has a physical meaning if it cannot be withdrawn without reducing the predictive power of a theory or, in a weaker sense, if it cannot be withdrawn without reducing the descriptive proficiency of a theory.

8

Vector potential, electromagnetic induction and "physical meaning"  

CERN Document Server

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

Giuliani, Giuseppe

2010-01-01

9

TRR-1/M1 Core Analysis with MVP  

International Nuclear Information System (INIS)

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

10

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.

11

Vector and scalar confining potentials and the Klein paradox  

International Nuclear Information System (INIS)

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

12

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

13

Algebraic solution for the vector potential in the Dirac equation  

CERN Document Server

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

Booth, H S; Jarvis, P D

2001-01-01

14

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

15

Vector potential in a unified field theory  

International Nuclear Information System (INIS)

A modificztion of a unified theory of gravitation and electromagnetism is given. The modification leads to a geometric interpretation of the electromagnetic potential: A?:A? is proportional to hsub(?)sup(5), a component of the five-dimensional equivalent of a tetrad. (author)

16

Vector potential in a unified field theory  

Energy Technology Data Exchange (ETDEWEB)

A modification of a unified theory of gravitation and electromagnetism is given. The modification leads to a geometric interpretation of the electromagnetic potential: A..mu..:A..mu.. is proportional to hsub(..mu..)sup(5), a component of the five-dimensional equivalent of a tetrad.

Smrz, P.K.

1981-01-01

17

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

18

WKB method for Dirac equation with vector and scalar potentials  

International Nuclear Information System (INIS)

A sequential scheme of the WKB method is developed for the Dirac equation in a central symmetrical field with scalar and vector variants of interaction. The view of relativistic wave functions in the classical allowed and forbidden regions, and the conditions of their matching at transition through the turning points are found. As applications of the developed method the relativistic analogy of Bohr-Sommerfeld quantization condition which contains a spin-orbital interaction in a mixture of scalar S(r) and vector V(r) potentials, and relativistic generalization of the Gamov formula for quasistationary level width of the spin 1/2 particle interacting with scalar and vector fields simultaneously are obtained. It is shown that for Coulomb and oscillator potentials with the mixed Lorentz structure the obtained rule of quantization exactly reproduces the energy spectrum

19

Recent developments of JAEA's Monte Carlo Code MVP for reactor physics applications  

International Nuclear Information System (INIS)

MVP is a general-purpose continuous-energy Monte Carlo code for neutron and photon transport calculations that has been developed since the late 1980's at Japan Atomic Energy Agency (JAEA, formerly JAERI). The MVP code is designed for nuclear reactor applications such as reactor core design/analysis, criticality safety and reactor shielding. This paper describes the MVP code and present its latest developments. Among the new capabilities of MVP we find: -) the perturbation method has been implemented for the change in k(eff); -) the eigenvalue calculations can be performed with an explicit treatment of delayed neutrons in which their fission spectra are taken into account; -) the capability of tallying the scattering matrix (group-to-group scattering cross sections); -) the implementation of an exact model for resonance elastic scattering; and -) a Monte Carlo perturbation technique is used to calculate reactor kinetics parameters

20

Slugs: Potential Novel Vectors of Escherichia coli O157  

OpenAIRE

Field and laboratory studies were performed to determine whether slugs could act as novel vectors for pathogen (e.g., Escherichia coli O157) transfer from animal feces to salad vegetables. Escherichia coli O157 was isolated from 0.21% of field slugs from an Aberdeenshire sheep farm. These isolates carried the verocytotoxin genes (vt1 and vt2) and the attaching and effacing gene (eae), suggesting that they are potentially pathogenic to humans. Strain typing using multilocus variable number tan...

Sproston, Emma L.; Macrae, M.; Ogden, Iain D.; Wilson, Michael J.; Strachan, Norval J. C.

2006-01-01

21

A survey of potential vectors of apricot chlorotic leaf roll  

OpenAIRE

A comparative survey was done in leafhopper populations captured in apricot orchards in two areas of Valencia, one with considerable natural spread of apricot chlorotic leaf roll (ACLR), and the other where such natural spread is virtually nonexistent. An identification of the leafhopper species found in the first and in the second area suggest that Neoaliturus haematoceps and/or Neoaliturus fertestratus are the potential vectors of ACLR, at least under the conditions of Valencia province. Ps...

Lla?cer Ill, Gerardo; Medina Piles, Vicente; Archelo?s, Dolores

1988-01-01

22

The Physical Entity of Vector Potential in Electromagnetism  

Directory of Open Access Journals (Sweden)

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

Vladimir Alexandr Leus

2013-07-01

23

Analogs of generalized hydrodynamic potentials in the theory of the vector Helmholtz equation and the vector wave equation  

International Nuclear Information System (INIS)

The authors introduce analogs of the generalized potential of a Gromeka field into the theory of the vector Helmholtz equation and the vector wave equation. These analogs are used to obtain rather large classes of solutions with the Hamilton description of the vector lines. These classes contain the known solutions of this type (those of Arnol'd-Beltrami-Childress and Zaslavskii-Sagdeev-Chernikov) as particular specializations. Particular analogs of the generations Gromeka potential field are introduced for a cylindrical coordinate system

24

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)

25

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)

26

Potentiality of experimental analysis for characteristics of the Poynting vector components  

OpenAIRE

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.; Mokhun I.; Viktorovskaya J.

2008-01-01

27

Design and Potential of Non-Integrating Lentiviral Vectors  

OpenAIRE

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

Aaron Shaw; Kenneth Cornetta

2014-01-01

28

Flux Ropes as Singularities of the Vector Potential  

CERN Document Server

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

Kleman, M

2014-01-01

29

Leishmaniasis vector potential of Lutzomyia spp. in Colombian coffee plantations.  

Science.gov (United States)

Potential vectors of Leishmania braziliensis Vianna were assessed at four study sites in the mountainous Valle del Cauca, western Colombia, from March to June 1989. In an active focus of transmission at 1450 m altitude, a coffee plantation at Versalles, there were high densities of antropophilic phlebotomines: Lutzomyia columbiana (Ritorcelli & Van Ty) and Lu.townsendi (Ortiz), both in the verrucarum species group, and of Lu.pia (Fairchild & Hertig). At a comparable altitude in a forest reserve at Yotoco where leishmaniasis is unknown, Lu.pia was the prevalent species and Lu.townsendi was absent. In two localities at 1150 m altitude, there were plentiful Lu.lichyi (Floch & Abonnenc) plus both species in the verrucarum group, but Lu.pia was absent. One of these localities, a coffee plantation at Villa Hermosa where a leishmaniasis outbreak occurred in 1986, was compared with a leishmaniasis-free, partly wooded nature reserve at Mateguadua. No natural infections of Leishmania were found in a total of 1896 wild-caught female phlebotomines belonging to at least seven species. It remains unclear why Leishmaniasis transmission is associated with coffee plantations in this part of Colombia. Laboratory-bred Lu.lichyi females were invariably autogenous, and blood-seeking females of this species were always parous. Parity rates in wild-caught females of other species were 55% Lu.pia, 24% Lu.columbiana and 14% Lu.townsendi. Female Lutzomyia infected artificially with Le.braziliensis promastigotes developed peripylarian infections. Higher proportions of Lu.townsendi (96%) and Lu.columbiana (78%) became infected but these species developed lower rates of stomodaeal infections (P less than 0.1) than Lu.lichyi (37%) or Lu.pia (44%).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1768906

Warburg, A; Montoya-Lerma, J; Jaramillo, C; Cruz-Ruiz, A L; Ostrovska, K

1991-01-01

30

Major vault protein (MVP) gene polymorphisms and drug resistance in mesial temporal lobe epilepsy with hippocampal sclerosis.  

Science.gov (United States)

The human major vault protein (MVP) has been implicated in the development of drug resistance in cancer cells. Over expression of MVP has also been reported in brain tissue samples from antiepileptic drug (AED)-resistant human focal epilepsies. To investigate the relationship between single nucleotide polymorphisms (SNPs) involving the MVP gene and AED-resistance, we compared the distribution of three SNPs in the MVP gene, rs4788187, rs3815824 and rs3815823, among 220 patients with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) (prototype of AED-resistant epilepsy syndrome), 201 patients with juvenile myoclonic epilepsy (JME) (prototype of AED-responsive epilepsy syndrome) and 213 ethnically matched non-epilepsy controls. All the patients and controls were residents of the South Indian state of Kerala for more than three generations. We did not find any significant difference in allele and genotypic frequencies of the studied SNPs between AED-resistant and AED-responsive cohorts, and between AED-resistant and AED-responsive cohorts independently and pooled together when compared with the controls. We conclude that rs4788187, rs3815824, rs3815823 variants of the MVP gene are associated neither with predisposition for epilepsy nor with AED-resistance in the population that we have studied. Our results suggest the need for further research into the link between MVP and AED-resistance. PMID:23751308

Balan, Shabeesh; Radhab, Saradalekshmi Koramannil; Radha, Koramannil; Sathyan, Sanish; Vijai, Joseph; Banerjee, Moinak; Radhakrishnan, Kurupath

2013-09-10

31

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

International Nuclear Information System (INIS)

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

32

Fractional fermion charges induced by vector-axial and vector gauge potentials in planar graphene-like structures  

CERN Document Server

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

Obispo, Angel E

2012-01-01

33

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

34

MVP expression in the prediction of clinical outcome of locally advanced oral squamous cell carcinoma patients treated with radiotherapy  

Directory of Open Access Journals (Sweden)

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

Henríquez-Hernández Luis

2012-08-01

35

Reconstruction of potential part of 3D vector field by using singular value decomposition  

International Nuclear Information System (INIS)

In this paper we suggest the method of 3D vector tomography problem solving. The problem consists in determination of potential part of 3D vector field by its known the normal Radon transform. The singular value decomposition of the normal Radon transform operator is obtained. Based on obtained decomposition inversion formula is derived. The decomposition can be the basis for numerical solution of given problem.

36

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

OpenAIRE

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

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

2011-01-01

37

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)

38

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

39

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

40

Stationary states of fermions in a sign potential with a mixed vector–scalar coupling  

Energy Technology Data Exchange (ETDEWEB)

The scattering of a fermion in the background of a sign 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 under the Sturm–Liouville perspective. When the vector coupling and the scalar coupling have different magnitudes, an isolated solution shows that the fermion under a strong potential can be trapped in a highly localized region without manifestation of Klein’s paradox. It is also shown that the lonely bound-state solution disappears asymptotically as one approaches the conditions for the realization of spin and pseudospin symmetries. -- Highlights: •Scattering of fermions in a sign potential assessed under a Sturm–Liouville perspective. •An isolated bounded solution. •No pair production despite the high localization. •No bounded solution under exact spin and pseudospin symmetries.

Castilho, W.M., E-mail: castilho.w@gmail.com; Castro, A.S. de, E-mail: castro@pq.cnpq.br

2014-01-15

41

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)

42

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)

43

C595 antibody: A potential vector for targeted alpha therapy  

International Nuclear Information System (INIS)

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

44

The vector potential and stored energy of thin cosine (n?) helical wiggler magnet  

International Nuclear Information System (INIS)

Expressions for pure multipole field components that are present in helical devices have been derived from a current distribution on the surface of an infinitely thin cylinder of radius R. The strength of such magnetic fields varies purely as a Fourier sinusoidal series of the longitudinal coordinate Z in proportion to cos(n?- ?mz), where ?m = (2m-1)?/L, L denotes the half-period and m = 1, 2, 3 etc. As an alternative to describing such field components as given by the negative gradient of a scalar potential function (Appendix A), one of course can derive these same fields as the curle of a vector potential function rvec A--specifically one for which ? x ? x rvec A = 0 and ?· rvec A = 0. It is noted that we seek a divergence-free vector that exhibits continuity in any of its components across the interface r = R, a feature that is free of possible concern when applying Stokes' theorem in connection with this form of vector potential. Alternative simpler forms of vector potential, that individually are divergence-free in their respective regions (r R), do not exhibit full continuity on r = R and whose curl evaluations provide in these respective regions the correct components of magnetic field are not considered here. Such alternative forms must differ merely by the gradient of scalar functions that with the divergence-free property are required to be ''harmonic'' (?2? = 0)

45

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.

46

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

OpenAIRE

Scattering and bound states for a spinless particle in the background of a kink-like smooth step potential, added with a scalar uniform background, are considered with a general mixing of vector and scalar Lorentz structures. The problem is mapped into the Schr\\"{o}dinger-like equation with an effective Rosen-Morse potential. It is shown that the scalar uniform background present subtle and trick effects for the scattering states and reveals itself a high-handed element for ...

Garcia, M. G.; Castro, A. S.

2009-01-01

47

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

48

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)

49

Predicting and mapping malaria under climate change scenarios: the potential redistribution of malaria vectors in Africa  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Malaria is rampant in Africa and causes untold mortality and morbidity. Vector-borne diseases are climate sensitive and this has raised considerable concern over the implications of climate change on future disease risk. The problem of malaria vectors (Anopheles mosquitoes shifting from their traditional locations to invade new zones is an important concern. The vision of this study was to exploit the sets of information previously generated by entomologists, e.g. on geographical range of vectors and malaria distribution, to build models that will enable prediction and mapping the potential redistribution of Anopheles mosquitoes in Africa. Methods The development of the modelling tool was carried out through calibration of CLIMEX parameters. The model helped estimate the potential geographical distribution and seasonal abundance of the species in relation to climatic factors. These included temperature, rainfall and relative humidity, which characterized the living environment for Anopheles mosquitoes. The same parameters were used in determining the ecoclimatic index (EI. The EI values were exported to a GIS package for special analysis and proper mapping of the potential future distribution of Anopheles gambiae and Anophles arabiensis within the African continent under three climate change scenarios. Results These results have shown that shifts in these species boundaries southward and eastward of Africa may occur rather than jumps into quite different climatic environments. In the absence of adequate control, these predictions are crucial in understanding the possible future geographical range of the vectors and the disease, which could facilitate planning for various adaptation options. Conclusion Thus, the outputs from this study will be helpful at various levels of decision making, for example, in setting up of an early warning and sustainable strategies for climate change and climate change adaptation for malaria vectors control programmes in Africa.

Kangalawe Richard YM

2010-04-01

50

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

51

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

52

MVP expression in the prediction of clinical outcome of locally advanced oral squamous cell carcinoma patients treated with radiotherapy  

OpenAIRE

Abstract Objective To explore the role of Major Vault Protein (MVP) in oral cavity squamous cell carcinoma patients. Subjects and Methods 131 consecutive patients suffering from oral cavity squamous cell carcinoma were included in the study. In the whole series, the mean follow-up for survivors was 123.11?±?40.36?months. Patients in tumour stages I and II were referred to surgery; patients in stage III-IV to postoperative radiotherapy (mean dose?=?62....

Henríquez-Hernández Luis; Moreno Mercedes; Rey Agustín; Lloret Marta; Lara Pedro C

2012-01-01

53

Abelian Magnetic Monopoles and Topologically Massive Vector Bosons in Scalar-Tensor Gravity with Torsion Potential  

OpenAIRE

A Lagrangian formulation describing the electromagnetic interaction - mediated by topologically massive vector bosons - between charged, spin-(1/2) fermions with an abelian magnetic monopole in a curved spacetime with non-minimal coupling and torsion potential is presented. The covariant field equations are obtained. The issue of coexistence of massive photons and magnetic monopoles is addressed in the present framework. It is found that despite the topological nature of pho...

Capozziello, Salvatore

2008-01-01

54

Chikungunya Viral Fitness Measures within the Vector and Subsequent Transmission Potential  

OpenAIRE

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

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

2014-01-01

55

The vector potential and stored energy of thin cosine (n{theta}) helical wiggler magnet  

Energy Technology Data Exchange (ETDEWEB)

Expressions for pure multipole field components that are present in helical devices have been derived from a current distribution on the surface of an infinitely thin cylinder of radius R. The strength of such magnetic fields varies purely as a Fourier sinusoidal series of the longitudinal coordinate Z in proportion to cos(n{theta}- {omega}{sub m}z), where {omega}{sub m} = (2m-1){pi}/L, L denotes the half-period and m = 1, 2, 3 etc. As an alternative to describing such field components as given by the negative gradient of a scalar potential function (Appendix A), one of course can derive these same fields as the curle of a vector potential function {rvec A}--specifically one for which {nabla} {times} {nabla} {times} {rvec A} = 0 and {nabla}{center_dot}{rvec A} = 0. It is noted that we seek a divergence-free vector that exhibits continuity in any of its components across the interface r = R, a feature that is free of possible concern when applying Stokes` theorem in connection with this form of vector potential. Alternative simpler forms of vector potential, that individually are divergence-free in their respective regions (r < R and r > R), do not exhibit full continuity on r = R and whose curl evaluations provide in these respective regions the correct components of magnetic field are not considered here. Such alternative forms must differ merely by the gradient of scalar functions that with the divergence-free property are required to be ``harmonic`` ({nabla}{sup 2}{Psi} = 0).

Caspi, S.

1995-12-01

56

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

International Nuclear Information System (INIS)

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

57

Mapping from current densities to vector potentials in time-dependent current-density functional theory  

OpenAIRE

We show that the time-dependent particle density $n(\\vec r,t)$ and the current density ${\\vec j}(\\vec r,t)$ of a many-particle system that evolves under the action of external scalar and vector potentials $V(\\vec r,t)$ and $\\vec A(\\vec r,t)$ and is initially in the quantum state $|\\psi (0)>$, can always be reproduced (under mild assumptions) in another many-particle system, with different two-particle interaction, subjected to external potentials $V'(\\vec r,t)$ and $\\vec A'(...

Vignale, G.

2004-01-01

58

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

59

Seasonal dynamics of biting midges (Diptera: Ceratopogonidae: Culicoides), the potential vectors of bluetongue virus, in Sweden.  

Science.gov (United States)

The outbreak of bluetongue (BT) in northern Europe 2006 initiated the monitoring of vectors, biting midges of the genus Culicoides in Sweden. In order to determine the diversity, distribution and seasonal dynamics of Culicoides, weekly collections were made during 2008 and during March-December 2009 using the Ondestepoort Veterinary Institute black light trap. Twenty sampling sites were selected in 12 provinces. In total of 30,704 Culicoides were collected in 2008 and 32,252 in 2009. The most abundant species were the potential vectors of BTV Culicoides obsoletus/C. scoticus that comprised of 77% of the total catches. Other biting midges collected were Culicoides impunctatus (9%), Culicoides grisescens (3%), Culicoides punctatus (2%), Culicoides chiopterus (2%) and Culicoides pulicaris (2%). Culicoides obsoletus/C. scoticus were most abundant during May-June and August-September. The majority of the species were active from March to November in 2008 and April to October in 2009. Species considered as potential vectors of bluetongue virus (BTV) occurred as far north as latitude 65°N (Kalix). PMID:21944873

Ander, M; Meiswinkel, R; Chirico, J

2012-02-28

60

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

Directory of Open Access Journals (Sweden)

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

MIHAIL-CRISTIAN DI?OIU

2011-01-01

61

SO(N) Higgs problem with adjoint + vector representations and non-linear potentials  

International Nuclear Information System (INIS)

Using the recently devised geometrical method, we analyze the quartic Higgs potential for SO(N) adjoint + vector representations. The minimum energy solutions are found to correspond to maxi-maximal little groups, but not all such groups are used. However, in the complete orbit space (including invariants not employed in the Higgs potential) we find that their strata have somewhat equal geometrical status of being low dimensional singular subspaces, i.e., cusps, edge curves, two-dimensional surfaces, etc. We also consider simple scalar potentials which are nonlinear with respect to orbit parameters and show that the directional extremum often, though not always, remains monotonic in orbit parameters within the orbit space and consequently the absolute extremum is likely to occur on the most protrudent portions of the orbit space boundary. Thus we clarify the range of validity of the Michel-Radicati conjecture and the Gell-Mann-Slansky conjecture. (orig.)

62

Oviposition deterring and oviciding potentials of Ipomoea cairica L. leaf extract against dengue vectors.  

Science.gov (United States)

Bioprospecting of plant-based insecticides for vector control has become an area of interest within the last two decades. Due to drawbacks of chemical insecticides, phytochemicals of plant origin with mosquito control potential are being utilized as alternative sources in integrated vector control. In this regard, the present study aimed to investigate oviposition deterring and oviciding potentials of Ipomoea cairica (L.) (Family: Convolvulaceae) crude leaf extract against dengue vectors, Aedes aegypti and Aedes albopictus. Ipomoea cairica is an indigenous plant that has demonstrated marked toxicity towards larvae of Ae. aegypti and Ae. albopictus. Leaves of I. cairica were extracted using Soxhlet apparatus with acetone as solvent. Oviposition deterrent activity and ovicidal assay was carried out in oviposition site choice tests with three different concentrations (50, 100, 450 ppm). Acetone extract of I. cairica leaf strongly inhibited oviposition with 100% repellence to Ae. aegypti at lower concentration of 100 ppm, while for Ae. albopictus was at 450 ppm. The oviposition activity index (OAI) values which ranged from -0.69 to -1.00 revealed that I. cairica demonstrated deterrent effect. In ovicidal assay, similar trend was observed whereby zero hatchability was recorded for Ae. aegypti and Ae. albopictus eggs at 100 and 450 ppm, respectively. It is noteworthy that I. cairica leaf extract had significantly elicited dual properties as oviposition deterrent and oviciding agent in both Aedes species. Reduction in egg number through oviposition deterring activity, reduction in hatching percentage and survival rates, suggested an additional hallmark of this plant to be integrated in Aedes mosquito control. Ipomoea cairica deserved to be considered as one of the potential alternative sources for the new development of novel plant based insecticides in future. PMID:25382472

Ahbirami, Rattanam; Zuharah, Wan Fatma; Yahaya, Zary Shariman; Dieng, Hamady; Thiagaletchumi, Maniam; Fadzly, Nik; Ahmad, Abu Hassan; Abu Bakar, Sazaly

2014-09-01

63

Calculations for a disk source and a general detector using a radiation vector potential  

International Nuclear Information System (INIS)

A closed form expression for a radiation vector potential is derived for a generalized disk radiation source. By applying Stokes's theorem the surface integral for the radiation flux into a general detector is converted into a much simpler line integral of the vector potential around the edge of the detector. This line integral can be easily evaluated for general detector geometry and general location and angular orientation relative to the disk source. For a number of cases the line integral reduces to integrals of Bessel functions which give various generalizations of Ruby's formula. Explicit formulas and numerical results for the geometric efficiency are given for circular and elliptical detectors displaced and rotated relative to the disk source. Detectors with general polygonal boundaries are considered and formulas and sample numerical results are given. For uniform surface emissivity the corresponding formulas for a disk detector and a general planar source are easily obtained. Formulas are also obtained for a scalar radiation potential and some limitations for its applicability are identified

64

MHD Equilibrium with Reversed Current Density and Magnetic Islands Revisited: the Vacuum Vector Potential Calculus  

International Nuclear Information System (INIS)

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

65

A single mutation in chikungunya virus affects vector specificity and epidemic potential.  

Science.gov (United States)

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 compared in Aedes albopictus, the species implicated in the epidemic, and the recognized vector Ae. aegypti. Using viral infectious clones of the Reunion strain and a West African strain of CHIKV, into which either the E1-226 A or V mutation was engineered, we demonstrated that the E1-A226V mutation was directly responsible for a significant increase in CHIKV infectivity for Ae. albopictus, and led to more efficient viral dissemination into mosquito secondary organs and transmission to suckling mice. This mutation caused a marginal decrease in CHIKV Ae. aegypti midgut infectivity, had no effect on viral dissemination, and was associated with a slight increase in transmission by Ae. aegypti to suckling mice in competition experiments. The effect of the E1-A226V mutation on cholesterol dependence of CHIKV was also analyzed, revealing an association between cholesterol dependence and increased fitness of CHIKV in Ae. albopictus. Our observation that a single amino acid substitution can influence vector specificity provides a plausible explanation of how this mutant virus caused an epidemic in a region lacking the typical vector. This has important implications with respect to how viruses may establish a transmission cycle when introduced into a new area. Due to the widespread distribution of Ae. albopictus, this mutation increases the potential for CHIKV to permanently extend its range into Europe and the Americas. PMID:18069894

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

2007-12-01

66

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.

1990-09-01

67

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

68

Spinless particles in the field of unequal scalar—vector Yukawa potentials  

International Nuclear Information System (INIS)

We present analytical bound state solutions of the spin-zero Klein—Gordon (KG) particles in the field of unequal mixture of scalar and vector Yukawa potentials within the framework of the approximation scheme to the centrifugal potential term for any arbitrary l-state. The approximate energy eigenvalues and unnormalized wave functions are obtained in closed forms using a simple shortcut of the Nikiforov—Uvarov (NU) method. Further, we solve the KG—Yukawa problem for its exact numerical energy eigenvalues via the amplitude phase (AP) method to test the accuracy of the present solutions found by using the NU method. Our numerical tests using energy calculations demonstrate the existence of inter-dimensional degeneracy amongst the energy states of the KG—Yukawa problem. The dependence of the energy on the dimension D is numerically discussed for spatial dimensions D = 2–6. (general)

69

Barcoding Turkish Culex mosquitoes to facilitate arbovirus vector incrimination studies reveals hidden diversity and new potential vectors.  

Science.gov (United States)

As a precursor to planned arboviral vector incrimination studies, an integrated systematics approach was adopted using morphology and DNA barcoding to examine the Culex fauna present in Turkey. The mitochondrial COI gene (658bp) were sequenced from 185 specimens collected across 11 Turkish provinces, as well as from colony material. Although by morphology only 9 species were recognised, DNA barcoding recovered 13 distinct species including: Cx. (Barraudius) modestus, Cx. (Culex) laticinctus, Cx. (Cux.) mimeticus, Cx. (Cux.) perexiguus, Cx. (Cux.) pipiens, Cx. (Cux.) pipiens form molestus, Cx. (Cux.) quinquefasciatus, Cx. (Cux.) theileri, Cx. (Cux.) torrentium, Cx. (Cux.) tritaeniorhynchus and Cx. (Maillotia) hortensis. The taxon formerly identified as Cx. (Neoculex) territans was shown to comprise two distinct species, neither of which correspond to Cx. territans s.s. These include Cx. (Neo.) impudicus and another uncertain species, which may be Cx. (Neo.) europaeus or Cx. (Neo.) martinii (herein=Cx. (Neo.) sp. 1). Detailed examination of the Pipiens Group revealed Cx. pipiens, Cx. pipiens f. molestus and the widespread presence of the highly efficient West Nile virus vector Cx. quinquefasciatus for the first time. Four new country records are reported, increasing the Culex of Turkey to 15 recognised species and Cx. pipiens f. molestus. A new taxonomic checklist is provided, annotated with respective vector competencies for transmission of arboviruses. PMID:25446171

Gunay, Filiz; Alten, Bulent; Simsek, Fatih; Aldemir, Adnan; Linton, Yvonne-Marie

2014-10-25

70

Feeding behaviour of potential vectors of West Nile virus in Senegal  

Directory of Open Access Journals (Sweden)

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

Konaté Lassana

2011-06-01

71

Relativistic comparison theorems for the Klein–Gordon equation with scalar and vector potentials in d-dimensions  

International Nuclear Information System (INIS)

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

72

Ruthenium complexing during sorption by graft copolymer of polyacrylonitrile fibre with poly-2-methyl-5-vnylpyridine (PAN-MVP)  

International Nuclear Information System (INIS)

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

73

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)

74

Screening Mosquito House Entry Points as a Potential Method for Integrated Control of Endophagic Filariasis, Arbovirus and Malaria Vectors  

OpenAIRE

BACKGROUND Partial mosquito-proofing of houses with screens and ceilings has the potential to reduce indoor densities of malaria mosquitoes. We wish to measure whether it will also reduce indoor densities of vectors of neglected tropical diseases. METHODOLOGY The main house entry points preferred by anopheline and culicine vectors were determined through controlled experiments using specially designed experimental huts and village houses in Lupiro village, southern Tanzania. The b...

Ogoma, Sheila B.; Lweitoijera, Dickson W.; Ngonyani, Hassan; Furer, Benjamin; Russell, Tanya L.; Mukabana, Wolfgang R.; Killeen, Gerry F.; Moore, Sarah J.

2010-01-01

75

Molecular investigation of hard ticks (Acari: Ixodidae) and fleas (Siphonaptera: Pulicidae) as potential vectors of rickettsial and mycoplasmal agents  

OpenAIRE

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

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

2009-01-01

76

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

77

New Gastropod Vectors and Tetrodotoxin Potential Expansion in Temperate Waters of the Atlantic Ocean  

Directory of Open Access Journals (Sweden)

Full Text Available Tetrodotoxin is a potent low weight marine toxin found in warm waters, especially of the Indian and Pacific Oceans. Intoxications are usually linked to the consumption of the puffer fish, although TTX was already detected in several different edible taxa. Benthic organisms such as mollusks and echinoderms, with different feeding habits, were collected monthly along the Portuguese coast from the summer of 2009 until the end of 2010. The extraction and analysis techniques were optimized and TTX and some analogues were detected for the first time in two intertidal gastropod species—Gibbula umbilicalis and Monodonta lineata by LC-MS/MS and UPLC-MS/MS. Although the levels are low, these findings suggest that monitoring of TTX and analogues in North Atlantic species should be implemented so as to detect potentially new toxin vectors and seasonal and/or geographical patterns.

Vítor Vasconcelos

2012-03-01

78

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

Science.gov (United States)

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

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

2011-05-31

79

Aedes hensilli as a Potential Vector of Chikungunya and Zika Viruses  

OpenAIRE

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...

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

2014-01-01

80

Urinary nucleosides as potential tumor markers evaluated by learning vector quantization.  

Science.gov (United States)

Modified nucleosides were recently presented as potential tumor markers for breast cancer. The patterns of the levels of urinary nucleosides are different for tumor bearing individuals and for healthy individuals. Thus, a powerful pattern recognition method is needed. Although backpropagation (BP) neural networks are becoming increasingly common in medical literature for pattern recognition, it has been shown that often-superior methods exist like learning vector quantization (LVQ) and support vector machines (SVM). The aim of this feasibility study is to get an indication of the performance of urinary nucleoside levels evaluated by LVQ in contrast to the evaluation the popular BP and SVM networks. Urine samples were collected from female breast cancer patients and from healthy females. Twelve different ribonucleosides were isolated and quantified by a high performance liquid chromatography (HPLC) procedure. LVQ, SVM and BP networks were trained and the performance was evaluated by the classification of the test sets into the categories "cancer" and "healthy". All methods showed a good classification with a sensitivity ranging from 58.8 to 70.6% at a specificity of 88.4-94.2% for the test patterns. Although the classification performance of all methods is comparable, the LVQ implementations are superior in terms of more qualitative features: the results of LVQ networks are more reproducible, as the initialization is deterministic. The LVQ networks can be trained by unbalanced sizes of the different classes. LVQ networks are fast during training, need only few parameters adjusted for training and can be retrained by patterns of "local individuals". As at least some of these features play an important role in an implementation into a medical decision support system, it is recommended to use LVQ for an extended study. PMID:12927336

Dieterle, Frank; Müller-Hagedorn, Silvia; Liebich, Hartmut M; Gauglitz, Günter

2003-07-01

81

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

Science.gov (United States)

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

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

2011-03-01

82

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-03-21

83

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.

84

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)

85

Maximizing sparse matrix vector product performance in MIMD computers  

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-12-31

86

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

International Nuclear Information System (INIS)

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

87

Stokesian and non-Stokesian vector potentials in quantum mechanics. Comments on a letter by U. Klein  

International Nuclear Information System (INIS)

This letter shows that recent criticisms by U. Klein against two papers of ours, concerning the Aharonov-Bohm effect, are not correct. It is shown, in particular, that the use of a non-Stokesian vector potential in quantum mechanics does not lead in any case to an ''inverse'' Aharonov-Bohm effect. (author)

88

Solutions of the Klein-Gordon equation with equal scalar and vector harmonic oscillator plus inverse quadratic potential  

Science.gov (United States)

The solutions of the Klein-Gordon equation with equal scalar and vector harmonic oscillator plus inverse quadratic potential for S-waves have been presented using the Nikiforov-Uvarov method. The bound state energy eigenvalues and the corresponding un-normalized eigenfunctions are obtained in terms of the Laguerre polynomials.

Ita, B. I.; Obong, H. P.; Ehi-Eromosele, C. O.; Edobor-Osoh, A.; Ikeuba, A. I.

2014-11-01

89

Solutions to the Klein—Gordon Equation with Equal Scalar and Vector Modified Hylleraas Plus Exponential Rosen Morse Potentials  

International Nuclear Information System (INIS)

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

90

Impact of low aerial application rates of Dibrom 14 on potential vectors.  

Science.gov (United States)

Aerial applications designed to assess the impact of low application rates of naled (Dibrom 14) on potential vector species were conducted in 2003 with caged adult Anopheles quadrimaculatus in open grassland at Cecil Airfield in Jacksonville, FL. Offset flight paths of 2,000-6,000 (calculated by the AgDisp aerial application model) and 1,000-ft swath widths were conducted with a Micronair AU4000 rotary atomizer, which provides a several-fold increase in droplets between 7 and 22 microm. Mean volume median diameters of 8.0, 7.8, and 9.4 microm and 290, 506, and 192 droplets per sq cm were observed in the target area with application rates of 0.125, 0.25, and 0.5 fl oz per acre, respectively. The observed mean mortality of caged mosquitoes 12 h posttreatment, corrected for mortality in untreated controls, was 14%, 80%, and 99% at 0.125, 0.25, and 0.5 fl oz per acre, respectively. These results indicate that applications at 0.25 fl oz per acre or less should be avoided and rates greater than 0.5 fl oz may be required for adequate control in canopied habitats and less-than-optimum terrains. PMID:16646327

Brown, James R; Rutledge, Cynthia R; Reynolds, William; Dame, David A

2006-03-01

91

Potential of cancer screening with serum surface-enhanced Raman spectroscopy and a support vector machine  

Science.gov (United States)

Cancer is the most common disease to threaten human health. The ability to screen individuals with malignant tumours with only a blood sample would be greatly advantageous to early diagnosis and intervention. This study explores the possibility of discriminating between cancer patients and normal subjects with serum surface-enhanced Raman spectroscopy (SERS) and a support vector machine (SVM) through a peripheral blood sample. A total of 130 blood samples were obtained from patients with liver cancer, colonic cancer, esophageal cancer, nasopharyngeal cancer, gastric cancer, as well as 113 blood samples from normal volunteers. Several diagnostic models were built with the serum SERS spectra using SVM and principal component analysis (PCA) techniques. The results show that a diagnostic accuracy of 85.5% is acquired with a PCA algorithm, while a diagnostic accuracy of 95.8% is obtained using radial basis function (RBF), PCA–SVM methods. The results prove that a RBF kernel PCA–SVM technique is superior to PCA and conventional SVM (C-SVM) algorithms in classification serum SERS spectra. The study demonstrates that serum SERS, in combination with SVM techniques, has great potential for screening cancerous patients with any solid malignant tumour through a peripheral blood sample.

Li, S. X.; Zhang, Y. J.; Zeng, Q. Y.; Li, L. F.; Guo, Z. Y.; Liu, Z. M.; Xiong, H. L.; Liu, S. H.

2014-06-01

92

Intercontinental genetic structure and gene flow in Dunlin (Calidris alpina), a potential vector of avian influenza  

Science.gov (United States)

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

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

2015-01-01

93

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

International Nuclear Information System (INIS)

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

94

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

95

Potential vectors of West Nile virus following an equine disease outbreak in Italy.  

Science.gov (United States)

In the late summer of 1998, an outbreak of equine encephalomyelitis due to West Nile virus (WNV) occurred in the Tuscany region of central Italy. The disease was detected in 14 race horses from nine localities in four Provinces: Firenze, Lucca, Pisa and Pistoia. The outbreak area included Fucecchio wetlands (1800 ha), the largest inland marsh in Italy, and the adjacent hilly Cerbaie woodlands with farms breeding horses. To detect potential vectors of WNV, entomological surveys of Fucecchio and Cerbaie were undertaken during 1999-2002 by collecting mosquito larvae from breeding sites and adult mosquitoes by several methods of sampling. Among 6023 mosquitoes (Diptera: Culicidae) collected, 11 species were identified: Aedes albopictus (Skuse), Ae. vexans (Meigen), Anopheles atroparvus Van Thiel, An. maculipennis Meigen s.s., An. plumbeus Stephens, Culex impudicus Ficalbi, Cx. pipiens L., Culiseta longiareolata Macquart), Ochlerotatus caspius (Pallas), Oc. detritus (Haliday) and Oc. geniculatus (Olivier). In Fucecchio marshes, Cx. impudicus predominated with seasonal peak densities in spring and autumn: its greatest abundance during early spring coincides with arrival of migratory birds from Africa. In Cerbaie hills, Cx. pipiens predominated with peak population density in late summer. No viruses were isolated from 665 mosquitoes processed. These findings, plus other data on Italian mosquito bionomics, suggest a possible mode of WNV transmission involving the most abundant Culex in the Fucecchio-Cerbaie areas. Culex impudicus, being partly ornithophilic, might transmit WNV from migratory to non-migratory birds during springtime; Cx. pipiens, having a broader host range, would be more likely to transmit WNV from birds to horses and, perhaps, to humans by late summer. PMID:15009441

Romi, R; Pontuale, G; CIufolini, M G; Fiorentini, G; Marchi, A; Nicoletti, L; Cocchi, M; Tamburro, A

2004-03-01

96

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

Directory of Open Access Journals (Sweden)

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

Richardson Jason H

2009-07-01

97

Direct gene delivery to synovium. An evaluation of potential vectors in vitro and in vivo.  

OpenAIRE

OBJECTIVE: To assess the abilities of various vectors to transfer genes to the synovial lining of joints. METHODS: Vectors derived from retrovirus, adenovirus, and herpes simplex virus as well as cationic liposomes and naked plasmid DNA were evaluated. Each construct contained the lac Z marker gene; and one retroviral construct, and one plasmid also contained a gene encoding human interleukin-1 receptor antagonist. Gene expression was under the control of the human cytomegalovirus promoter in...

Nita, I.; Ghivizzani, Sc; Galea-lauri, J.; Bandara, G.; Georgescu, Hi; Robbins, Pd; Evans, Ch

1996-01-01

98

Predicting and mapping malaria under climate change scenarios: the potential redistribution of malaria vectors in Africa  

OpenAIRE

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

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

2010-01-01

99

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-08-16

100

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

OpenAIRE

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 compete...

Hmus, Mare L. X. F.; Anders Lindström; Rklund, Mats Bj X. F.

2012-01-01

101

Ecology of mosquitoes (Diptera, Culicidae) potentially vectors of arboviruses according to the kinds of animal husbandry in Belgium  

OpenAIRE

Human activity, commercial exchanges and climate changes current and future, could favor the (re)-emergence of vector-borne diseases, by inducing changes on Culicidae populations. This study aims to determine the potential importance of agricultural environments, especially cattle farms and equestrian, to welcome and favor the proliferation of some species of mosquito responsible for transmission of arboviruses. To better understand the structure of the Culicidae population and identify habit...

Boukraa, Slimane; La Grandie?re Noronha Cotta, Maria Ana; Bawin, Thomas; Raharimalala, Fara Nantenaina; Zimmer, Jean-yves; Haubruge, Eric; Thiry, Etienne; Francis, Fre?de?ric

2013-01-01

102

Complexing of ruthenium during sorption by a graft copolymer of a polyacrylonitrile fiber with poly-2-methvl-5-vinylpyridine (PAN-MVP)  

International Nuclear Information System (INIS)

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

103

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

OpenAIRE

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

104

Varroa destructor, a potential vector of Israeli Acute Paralysis Virus in honey bees, Apis mellifera  

Science.gov (United States)

Although the role of the parasitic mite, Varroa destructor, as a vector in transmission of viruses between honey bees is well established, no study has shown that it can similarly transmit Israeli Acute Paralysis Virus (IAPV), a virus that was found to be associated with Colony Collapse Disorder (CC...

105

Vector analysis  

CERN Document Server

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

Brand, Louis

2012-01-01

106

Worldwide niche and future potential distribution of Culicoides imicola, a major vector of bluetongue and African horse sickness viruses.  

Science.gov (United States)

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

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

2014-01-01

107

Potential for entomopathogenic fungi to control Triatoma dimidiata (Hemiptera: Reduviidae), a vector of Chagas disease in Mexico.  

Science.gov (United States)

Introduction The use of entomopathogenic fungi to control disease vectors has become relevant because traditional chemical control methods have caused damage to the environment and led to the development of resistance among vectors. Thus, this study assessed the pathogenicity of entomopathogenic fungi in Triatoma dimidiata. Methods Preparations of 108 conidia/ml of Gliocladium virens, Talaromyces flavus, Beauveria bassiana and Metarhizium anisopliae were applied topically on T. dimidiata nymphs and adults. Controls were treated with the 0.0001% Tween-80 vehicle. Mortality was evaluated and recorded daily for 30 days. The concentration required to kill 50% of T. dimidiata (LC50) was then calculated for the most pathogenic isolate. Results Pathogenicity in adults was similar among B. bassiana, G. virens and T. flavus (p>0.05) and differed from that in triatomine nymphs (p=0.009). The most entomopathogenic strains in adult triatomines were B. bassiana and G. virens, which both caused 100% mortality. In nymphs, the most entomopathogenic strain was B. bassiana, followed by G. virens. The native strain with the highest pathogenicity was G. virens, for which the LC50 for T. dimidiata nymphs was 1.98 x108 conidia/ml at 13 days after inoculation. Conclusions Beauveria bassiana and G. virens showed entomopathogenic potential in T. dimidiata nymphs and adults. However, the native G. virens strain presents a higher probability of success in the field, and G. virens should thus be considered a potential candidate for the biological control of triatomine Chagas disease vectors. PMID:25626650

Vázquez-Martínez, María Guadalupe; Cirerol-Cruz, Blanca Elva; Torres-Estrada, José Luis; López, Mario Henry Rodríguez

2014-12-01

108

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 interactions in the optical potential the depolarization 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 resulted by the fit of those 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,psub(o)) 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, Richard, Tepel, and Weidenmueller. Because of the target nucleus 27Al posesses in the ground state a spin I=5/2 also the possible quadrupole spin flip had to be included in the analysis. This was performed by coupled channel calculations. The depolarization data corrected according to compound contributions and quadrupole effects could now be applied to the study of the spin-spin potentials by means of DWBA calculations. As result it turned out 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. For the addition of a tensor term however no necessity resulted. (orig.)

109

Analysis of the inelastic ?-36Ar scattering and the 39K(p-vector, ?) 36Ar reaction using folding potentials  

International Nuclear Information System (INIS)

The elastic ?-scattering on 36Ar has been analysed in a broad range of energies using a double folded ?-optical potential. The cross sections were reproduced excellently and the extracted optical potentials show a nice systematic behaviour. The inelastic scattering has been analysed within the coupled-channel approach. Again the double-folded potentials lead to a very satisfactory description of the cross sections. The analyses proof the oblate shape of 36Ar. In microscopic finite-range DWBA analyses of the 39K(p-vector, ?)36Ar reaction the use of the folding potential yields a good description of the differential cross sections as well as the correct absolute values. 3 figs., 2 tabs., 11 refs. (author)

110

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

111

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

OpenAIRE

The possibility of non-trivial representations of the gauge group on wavefunctionals of a gauge invariant quantum field theory leads to a generation of mass for intermediate vector and tensor bosons. The mass parameters m show up as central charges in the algebra of constraints, which then become of second-class nature. The gauge group coordinates acquire dynamics outside the null-mass shell and provide the longitudinal field degrees of freedom that massless bosons need to f...

Calixto Molina, Manuel; Aldaya Valverde, Vi?ctor

1999-01-01

112

DYNAMICS OF THE PLAGUE TRANSMISSION CYCLE IN CENTRAL JAVA (ECOLOGY OF POTENTIAL FLEA VECTORS  

Directory of Open Access Journals (Sweden)

Full Text Available Setelah begitu lama tidak ada laporan mengenai peristiwa penyakit pes di Indonesia, maka tiba-tiba pada tahun 1968 - 1969 dilaporkan adanya 102 penderita, 42 meninggal dan tahun 1969 - 1970 penderita, 2 meninggal. Oleh karena itu diadakan suatu penelitian untuk mendapatkan data-data ecology penyakit pes di Boyolali, Jawa Tengah. Walaupun tidak ada peningkatan jumlah penderita, pada waktu itu telah dapat diisolasi adanya bakteri pes dari binatang mengerat dan pinjal. Ini berarti transmisi masih berlangsung; terus dan selalu mengancam kesehatan penduduk. Daerah infeksi Boyolali terdapat dilereng gunung Merapi dan Merbabu diatas ketinggian 1.000 m. Tiga jenis pinjal Xenopsylla cheopis, Stivalius cognatus dan Neopsylla sondaica ada hubungannya dengan binatang menyusui didaerah tersebut. Diatas ketinggian 1.000 m S. cognatus dan N. sondaica merupakan pinjal yang paling banyak ditemukan didaerah ladang, dan X. cheopis diperumahan des Pada ketinggian kurang dari 1.000 m tidak ditemukan S. cognatus dan N. sondaica sedangkan X. cheopis ditemukan didaerah ladang dan perumahan desa. Walaupun X. cheopis merupakan vector yang effisien dan jarang ditemukan didaerah ladang maka diduga bahwa pinjal tersebut tidak utama memegang peranan dalam penularan ini. Namun demikian pada masa epizootik X. cheopis mempunyai peranan pada siklus penularan antara binatang menyusui, binatang mengerat dan manusia. Sedangkan S. cognatus diduga merupakan vector utama, dan N. sondaica vector kedua, pada penularan pes. Jarangnya vector pada daerah ketinggian kurang 1.000 m, memperlihatkan bahwa pes di Jawa bersifat pegunungan. Kepadatan binatang menyusui yang merupakan reservoir utama dari penyakit pes yaitu Rattus exulans dan tiomanicus lebih banyak pada daerah ketinggian diatas 1.000 m. Binatang mengerat dan pinjal jarang ditemukan didaerah ladang, sedangkan jenis hutan di pinggiran sering ditemukan didaerah tempat tinggal, sehingga mengakibatkan kemungkinan terjadinya penularan penyakit pes pada manusia. Pengamatan pendahuluan menunjukkan bahwa berbagai jenis pinjal hidup pada binatang menyusui yang paling sering ditemukan saja baik diladang maupun di perumahan.

Ronald W. Turner

2012-09-01

113

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

Science.gov (United States)

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

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

2014-09-12

114

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

115

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)

116

Preprocess the Photospheric Vector Magnetograms for NLFFF Extrapolation using a Potential Field Model and an Optimization Method  

CERN Document Server

Numerical reconstruction/extrapolation of coronal nonlinear force-free magnetic field (NLFFF) usually takes the photospheric vector magnetogram as input at the bottom boundary. Magnetic field observed at the photosphere, however, contains force which is in conflict with the fundamental assumption of the force-free model and measurement noise which is unfavorable for practical computation. Preprocessing of the raw magnetogram has been proposed by Wiegelmann, Inhester, and Sakurai (2006) to remove the force and noise for providing better input for NLFFF modeling. In this paper we develop a new code of magnetogram preprocessing which is consistent with our extrapolation method CESE-MHD-NLFFF (Jiang, Feng, and Xiang, 2012; Jiang and Feng, 2012). Basing on a 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 deal with the two parts separately. Preprocessing of the magnetogram's potential part is based on a numerical potentia...

Jiang, Chaowei

2013-01-01

117

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

118

Potential Vectors of Dirofilaria immitis (Leidy, 1856) in Itacoatiara, Oceanic Region of Niterói Municipality, State of Rio de Janeiro, Brazil  

Scientific Electronic Library Online (English)

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

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

1998-07-01

119

Potential Vectors of Dirofilaria immitis (Leidy, 1856 in Itacoatiara, Oceanic Region of Niterói Municipality, State of Rio de Janeiro, Brazil  

Directory of Open Access Journals (Sweden)

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

Norma Labarthe

1998-07-01

120

Aphid (Hemiptera: Aphididae) species composition and potential aphid vectors of plum pox virus in Pennsylvania peach orchards.  

Science.gov (United States)

Plum pox, an invasive disease recently identified in Pennsylvania stone fruit orchards, is caused by the aphid-transmitted Plum pox virus (genus Potyvirus, family Potyviridae, PPV). To identify potential vectors, we described the aphid species communities and the seasonal dynamics of the dominant aphid species within Pennsylvania peach orchards. Aphids were trapped weekly in 2002 and 2003 from mid-April through mid-November within two central Pennsylvania orchards by using yellow and green water pan traps. In total, 42 aphid species were identified from both orchards over 2 yr. Within orchards, actual species richness ranged from 24 to 30 species. The Abundance Based Coverage Estimator predicted species richness to range from 30 to 36 species, indicating that trap catches were identifying most aphid species expected to occur in the orchard. Three species, Rhopalosiphum maidis (Fitch), Aphis spiraecola Patch, and Myzus persicae (Sulzer), were consistently dominant across locations and years. Orchard-trapped populations of these three species peaked in a similar chronological sequence each year. As expected, trap color influenced the total number and distribution of the predominate species collected. However, the same dominant species occurred in both yellow and green traps. Based on the seasonal population dynamics reported here and on published vector efficacy studies, the most probable significant PPV vector was identified as A. spiraecola. If the PPV pathogen escapes current quarantine or if subsequent reintroductions of PPV occur, these data will be useful for developing plum pox management strategies. PMID:16334309

Wallis, C M; Fleischer, S J; Luster, D; Gildow, F E

2005-10-01

121

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

122

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

123

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

124

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)

125

Larval Bradysia impatiens (Diptera: Sciaridae) potential for vectoring Pythium root rot pathogens.  

Science.gov (United States)

A series of laboratory experiments were conducted to investigate the capacity of Bradysia impatiens (Johannsen) larvae to ingest propagules from two strains each of Pythium aphanidermatum (Edson) Fitzp. and P. ultimum Trow and transmit the pathogens to healthy geranium seedlings on a filter-paper substrate in petri dishes. The capacity of fungus gnat larvae to transmit P. aphanidermatum to seedlings rooted in a commercial peat-based potting mix and germination of Pythium oospores and hyphal swellings before and after passage through the guts of larval fungus gnats were also examined. Assays revealed that Pythium spp. transmission by larval fungus gnats varied greatly with the assay substrate and also with the number and nature of ingested propagules. Transmission was highest (65%) in the petri dish assays testing larvae fed P. aphanidermatum K-13, a strain that produced abundant oospores. Transmission of strain K-13 was much lower (<6%) in plug cells with potting mix. Larvae were less efficient at vectoring P. ultimum strain PSN-1, which produced few oospores, and no transmission was observed with two non-oospore-producing strains: P. aphanidermatum Pa58 and P. ultimum P4. Passage of P. aphanidermatum K-13 through larval guts significantly increased oospore germination. However, decreased germination of hyphal swellings was observed following larval gut passage for strains of P. ultimum. These results expand previous studies suggesting that larval fungus gnats may vector Pythium spp. PMID:22085299

Braun, S E; Sanderson, J P; Wraight, S P

2012-03-01

126

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

127

Potential for entomopathogenic fungi to control Triatoma dimidiata (Hemiptera: Reduviidae), a vector of Chagas disease in Mexico  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction The use of entomopathogenic fungi to control disease vectors has become relevant because traditional chemical control methods have caused damage to the environment and led to the development of resi [...] stance among vectors. Thus, this study assessed the pathogenicity of entomopathogenic fungi in Triatoma dimidiata. Methods Preparations of 108 conidia/ml of Gliocladium virens, Talaromyces flavus, Beauveria bassiana and Metarhizium anisopliae were applied topically on T. dimidiata nymphs and adults. Controls were treated with the 0.0001% Tween-80 vehicle. Mortality was evaluated and recorded daily for 30 days. The concentration required to kill 50% of T. dimidiata (LC50) was then calculated for the most pathogenic isolate. Results Pathogenicity in adults was similar among B. bassiana, G. virens and T. flavus (p>0.05) and differed from that in triatomine nymphs (p=0.009). The most entomopathogenic strains in adult triatomines were B. bassiana and G. virens, which both caused 100% mortality. In nymphs, the most entomopathogenic strain was B. bassiana, followed by G. virens. The native strain with the highest pathogenicity was G. virens, for which the LC50 for T. dimidiata nymphs was 1.98 x108 conidia/ml at 13 days after inoculation. Conclusions Beauveria bassiana and G. virens showed entomopathogenic potential in T. dimidiata nymphs and adults. However, the native G. virens strain presents a higher probability of success in the field, and G. virens should thus be considered a potential candidate for the biological control of triatomine Chagas disease vectors.

María Guadalupe, Vázquez-Martínez; Blanca Elva, Cirerol-Cruz; José Luis, Torres-Estrada; Mario Henry Rodríguez, López.

2014-12-01

128

Analytical solution for the solid angle subtended at any point by an ellipse via a point source radiation vector potential  

International Nuclear Information System (INIS)

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

129

Assessing the potential of support vector machine for estimating daily solar radiation using sunshine duration  

International Nuclear Information System (INIS)

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

130

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

131

[Properties of potential vectors--derivatives of the broad-host--range plasmid RP4].  

Science.gov (United States)

Nonconjugative deletion and recombinant derivatives of the RP4 plasmid are constructed. The plasmids can be used as vectors because they have relatively small molecular weights, unique cleavage sites for enzymes EcoRI, XhoI, BamHI, PstI, KpnI, BglII, SalGI and HindIII (the plasmids pRP401 and pRP417 having six of these sites), and easily tested phenotypes (Tcr, Apr and Gal+). In addition, all of them retain the broad host range property. Also, the plasmid pRP420 is a multicopy derivative capable of amplification. The plasmids are mobilized by conjugative plasmids pRK2013 and Flac from Escherichia coli cells into Rhizobium meliloti and Pseudomonas aeruginosa strains. Flac-mediated mobilization of the pRP417 plasmid which has an internal deletion of the transposon Tn1, is decreased, in comparison with the nondeleted plasmid. ColE1 replication machinery is inhibited for RP4--ColE1 recombinant derivatives, if both components are joined via EcoRI restriction site. This inhibition does not depend on the orientation of joined molecules. ColE1 replication machinery is functional, if delta RP4 and ColE1-like plasmids are joined via PstI cleavage site. PMID:6094306

Riabchenko, L E; Sakanian, V A; Chernysheva, I P; Dobrovol'ski, P; Alikhanian, S I

1984-10-01

132

Seasonal dynamics of four potential West Nile vector species in north-central Texas.  

Science.gov (United States)

A population survey was conducted from April through September 2002 on mosquito species occurring on the Ray Roberts Greenbelt, a riparian corridor used for public recreation on the Elm Fork of the Trinity River, in Denton County, TX. Geographic information system software was used to set up a stratified random sampling design based on habitat parameters. Mosquitoes were collected using light traps, gravid traps, and resting boxes. A total of 29 species was collected during this study belonging to the following genera: Aedes, Anopheles, Coquillettidia, Culex, Mansonia, Ochlerotatus, Orthopodomyia, Psorophora, and Uranotaenia. The four most common species collected during this study were Aedes vexans, Culex erraticus, Culex salinarius, and Psorophora columbiae. West Nile virus (WNV) has been detected in these species in the United States, and they may serve as important vector species in Denton County. Collections were analyzed by the Texas Department of Health for arboviruses. One pool consisting of both Cx. erraticus and Cx. salinarius, collected in August 2002, tested positive for WNV, making it the first mosquito pool to test positive for WNV in Denton County. Canonical correspondence analysis was performed using abundance data of dominant species with selected weather variables and habitat parameters. Important factors for determining dominant species abundance were temperature, precipitation, dew point, and canopy coverage. Spatial and temporal patterns of these species are discussed. PMID:16599151

Bolling, Bethany G; Kennedy, James H; Zimmerman, Earl G

2005-12-01

133

The fully non-linear post-Friedmann frame-dragging vector potential: Magnitude and time evolution from N-body simulations  

CERN Document Server

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

Thomas, Daniel B; Wands, David

2015-01-01

134

Evaluation of a temperate climate mosquito, Ochlerotatus detritus (=Aedes detritus), as a potential vector of Japanese encephalitis virus.  

Science.gov (United States)

The U.K. has not yet experienced a confirmed outbreak of mosquito-borne virus transmission to people or livestock despite numerous autochthonous epizootic and human outbreaks of mosquito-borne diseases on the European mainland. Indeed, whether or not British mosquitoes are competent to transmit arboviruses has not been established. Therefore, the competence of a local (temperate) British mosquito species, Ochlerotatus detritus (=Aedes detritus) (Diptera: Culicidae) for transmission of a member of the genus Flavivirus, Japanese encephalitis virus (JEV) as a model for mosquito-borne virus transmission was assessed. The JEV competence in a laboratory strain of Culex quinquefasciatus (Diptera: Culicidae), a previously incriminated JEV vector, was also evaluated as a positive control. Ochlerotatus detritus adults were reared from field-collected juvenile stages. In oral infection bioassays, adult females developed disseminated infections and were able to transmit virus as determined by the isolation of virus in saliva secretions. When pooled at 7-21?days post-infection, 13% and 25% of O.?detritus were able to transmit JEV when held at 23?°C and 28?°C, respectively. Similar results were obtained for C.?quinquefasciatus. To our knowledge, this study is the first to demonstrate that a British mosquito species, O.?detritus, is a potential vector of an exotic flavivirus. PMID:25087926

Mackenzie-Impoinvil, L; Impoinvil, D E; Galbraith, S E; Dillon, R J; Ranson, H; Johnson, N; Fooks, A R; Solomon, T; Baylis, M

2015-03-01

135

Plum pox in north america: identification of aphid vectors and a potential role for fruit in virus spread.  

Science.gov (United States)

ABSTRACT Thirteen aphid species were tested for their ability to transmit Pennsylvania isolates of Plum pox virus (PPV) collected in Columbia (PENN-3), Franklin (PENN-4), and York (PENN-7) Counties, PA. Four species, Aphis fabae, A. spiraecola, Brachycaudus persicae, and Myzus persicae, consistently transmitted PPV in preliminary transmission tests. Two species, Metopolophium dirhodum and Rhopalosiphum padi, were occasional inefficient vectors. Toxoptera citricida, from Florida, also was an effective vector but it does not occur in major stone-fruit-growing states. Species not transmitting PPV in parallel tests included Acyrthosiphon pisum, Aphis glycines, Aulacorthum solani, Macrosiphum euphorbiae, Rhopalosiphum maidis, and Sitobion avenae. When given a 3-day probing access period simultaneously on PPV-infected peach seedlings and healthy peach seedlings, Myzus persicae, Aphis spiraecola, A. fabae, and B. persicae transmitted PPV to 63, 31, 38, and 32% of the healthy peach seedlings, respectively. When given a similar probing period on PPV-infected peach fruit and healthy peach seedlings, the same aphid species transmitted PPV to 50, 35, 0, and 0% of seedlings, respectively. Results support the hypothesis of secondary PPV spread by indigenous aphids in Pennsylvania, and suggest that PPV-infected fruit has the potential to function as a virus source for long-distance dispersal. PMID:18943108

Gildow, Frederick; Damsteegt, Vern; Stone, Andrew; Schneider, William; Luster, Douglas; Levy, Laurene

2004-08-01

136

Preliminary assessment of avian stomach oils: a vector of contaminants to chicks and potential for diet analysis and biomonitoring.  

Science.gov (United States)

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

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

2010-09-01

137

The normal matrix model with a monomial potential, a vector equilibrium problem, and multiple orthogonal polynomials on a star  

Science.gov (United States)

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

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

2015-02-01

138

Range-wide genetic population structure of common pochard (Aythya ferina): a potentially important vector of highly pathogenic avian influenza viruses  

OpenAIRE

An understanding of the distribution and spatial structure of the natural vectors of zoonothic pathogens is of interest for effective disease control and prevention. Here, we investigate the range-wide population genetic structure of common pochard (Aythya ferina), a long-distance migratory duck and potential vector of highly pathogenic avian influenza. We collected several hundred samples from breeding and wintering grounds across Eurasia including some H5N1-positive individuals and generate...

Liu, Yang; Keller, Irene; Heckel, Gerald

2011-01-01

139

Mapping the potential distribution of #Bandicota indica$, vector of zoonoses in Thailand, by use of remote sensing and geographic information systems (a case of Nakhon Pathom Province)  

OpenAIRE

Space technologies have been used increasingly for assessing the risk of infection by vector-borne diseases, providing tools for delimiting the distribution of vectors. As rodent-borne diseases are a growing concern in Thailand since the emergence of leptospirosis starting in 1998, this study was set up to determine the hazard, related to the potential presence of the main rodent with medical importance, Bandicota indica (Bechstein, 1800), the great bandicoot rat, widely distributed in the co...

Herbreteau, Vincent; Gonzalez, Jean-paul; Andrianasolo, Haja; Kittayapong, Pattamaporn; Hugot, Jean-pierre

2005-01-01

140

Rickettsia parkeri rickettsiosis in different ecological regions of Argentina and its association with Amblyomma tigrinum as a potential vector.  

Science.gov (United States)

Rickettsia parkeri, a newly recognized tick-borne pathogen of humans in the Americas, is a confirmed cause of spotted fever group rickettsiosis in Argentina. Until recently, almost all cases of R. parkeri rickettsiosis in Argentina have originated from the Paraná River Delta, where entomological surveys have identified populations of R. parkeri-infected Amblyomma triste ticks. In this report, we describe confirmed cases of R. parkeri rickettsiosis from Córdoba and La Rioja provinces, which are located several hundred kilometers inland, and in a more arid ecological region, where A. triste ticks do not occur. Additionally, we identified questing A. tigrinum ticks naturally infected with R. parkeri in Córdoba province. These data provide evidence that another human-biting tick species serves as a potential vector of R. parkeri in Argentina and possibly, other countries of South America. PMID:25349376

Romer, Yamila; Nava, Santiago; Govedic, Francisco; Cicuttin, Gabriel; Denison, Amy M; Singleton, Joseph; Kelly, Aubree J; Kato, Cecilia Y; Paddock, Christopher D

2014-12-01

141

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

142

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

OpenAIRE

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 (NO...

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

2002-01-01

143

Ants in a hospital environment and their potential as mechanical bacterial vectors  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Introduction We studied the richness and abundance of ant species, their bacteria and the bacteria isolated from patient clinical samples. Methods Ants were collected with baited traps at 64 sites in a public hospital in São Luis, State of Maranhão, Brazil. Results In total, 1,659 ants from 14 [...] species were captured. The most frequent species were Crematogaster victima, Solenopsis saevissima, Tapinoma melanocephalum, Camponotus vittatus and Paratrechina fulva. Forty-one species of bacteria were isolated from the ants and 18 from patients. Conclusions Ants are potential vehicles for pathogenic and opportunistic bacteria, and they can represent a risk factor in nosocomial infections.

Wanda Ramos dos Santos, Lima; Sirlei Garcia, Marques; Fernanda Souto, Rodrigues; Jose Manuel Macario, Rebelo.

2013-09-01

144

Potential impacts of climate change on the ecology of dengue and its mosquito vector the Asian tiger mosquito (Aedes albopictus)  

International Nuclear Information System (INIS)

Shifts in temperature and precipitation patterns caused by global climate change may have profound impacts on the ecology of certain infectious diseases. We examine the potential impacts of climate change on the transmission and maintenance dynamics of dengue, a resurging mosquito-vectored infectious disease. In particular, we project changes in dengue season length for three cities: Atlanta, GA; Chicago, IL and Lubbock, TX. These cities are located on the edges of the range of the Asian tiger mosquito within the United States of America and were chosen as test cases. We use a disease model that explicitly incorporates mosquito population dynamics and high-resolution climate projections. Based on projected changes under the Special Report on Emissions Scenarios (SRES) A1fi (higher) and B1 (lower) emission scenarios as simulated by four global climate models, we found that the projected warming shortened mosquito lifespan, which in turn decreased the potential dengue season. These results illustrate the difficulty in predicting how climate change may alter complex systems. (letter)

145

Potential impacts of climate change on the ecology of dengue and its mosquito vector the Asian tiger mosquito (Aedes albopictus)  

Science.gov (United States)

Shifts in temperature and precipitation patterns caused by global climate change may have profound impacts on the ecology of certain infectious diseases. We examine the potential impacts of climate change on the transmission and maintenance dynamics of dengue, a resurging mosquito-vectored infectious disease. In particular, we project changes in dengue season length for three cities: Atlanta, GA; Chicago, IL and Lubbock, TX. These cities are located on the edges of the range of the Asian tiger mosquito within the United States of America and were chosen as test cases. We use a disease model that explicitly incorporates mosquito population dynamics and high-resolution climate projections. Based on projected changes under the Special Report on Emissions Scenarios (SRES) A1fi (higher) and B1 (lower) emission scenarios as simulated by four global climate models, we found that the projected warming shortened mosquito lifespan, which in turn decreased the potential dengue season. These results illustrate the difficulty in predicting how climate change may alter complex systems.

Erickson, R. A.; Hayhoe, K.; Presley, S. M.; Allen, L. J. S.; Long, K. R.; Cox, S. B.

2012-09-01

146

Clinical-scale lentiviral vector transduction of PBL for TCR gene therapy and potential for expression in less differentiated cells  

OpenAIRE

In human gene therapy applications, lentiviral vectors may have advantages over gamma-retroviral vectors because of their ability to transduce non-dividing cells, their resistance to gene silencing, and a lack of integration site preference. In this study, we utilized VSV-G pseudotype third generation lentiviral vectors harboring specific anti-tumor T-cell receptor (TCR) to establish clinical-scale lentiviral transduction of PBL. Spinoculation (1000 × g, 32°C for 2 h) in the presence of pro...

Yang, Shicheng; Rosenberg, Steven A.; Morgan, Richard A.

2008-01-01

147

SV40 pseudovirions as highly efficient vectors for gene transfer and their potential application in cancer therapy.  

Science.gov (United States)

Among viral and non-viral gene delivery systems, SV40-based vectors show great promise in the cancer gene therapy field. SV40 vectors very efficiently deliver genes such as anti-viral agents, DNA vaccine, genes for chemoprotection (such as ABC transporters genes), suicide genes and antiangiogenic genes. The recombinant SV40 vectors can infect a wide variety of cells-dividing cells as well as non-cycling ones. Most of the SV40-based vectors can incorporate larger transgenes than the capacity of the SV40 wild-type, which is 5.2 kb; Moreover, in vitro packaged vectors demonstrate efficient delivery of plasmids with a molecular weight of up to 17.7 kb. SV40-based vectors carry some SV40 viral sequences, but the SV40 in vitro-packaged vectors are free of any SV40 wild-type viral DNA sequences. These vectors are prepared with nuclear extracts of SF9 insect cells containing the main viral capsid protein of the SV40 wild-type virus, VP1. This review summarizes different strategies in which SV40 vectors are used to deliver genes in vitro, to living mice, and to tumors growing in nude mice. PMID:15544493

Kimchi-Sarfaty, Chava; Gottesman, Michael M

2004-10-01

148

Tagosodes orizicolus: nuevo vector potencial del Mal de Río Cuarto virus Tagosodes orizicolus: a new potential vector of Mal de Río Cuarto virus  

Directory of Open Access Journals (Sweden)

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

María Fernanda Mattio

2008-06-01

149

Exact solution of the one-dimensional Klein–Gordon equation with scalar and vector linear potentials in the presence of a minimal length  

International Nuclear Information System (INIS)

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

150

Exact Solutions of the Klein-Gordon Equation with Position-Dependent Mass for Mixed Vector and Scalar Kink-Like Potentials  

International Nuclear Information System (INIS)

The relativistic problem of spinless particles with position-dependent mass subject to kink-like potentials is investigated. By using the basic concepts of the supersymmetric quantum mechanics formalism and the functional analysis method, we solve exactly the position-dependent effective mass Klein-Gordon equation with the vector and scalar kink-like potential coupling, and obtain the bound state solutions in the closed form. It is found that in the presence of position-dependent mass there exists the symmetry that the discrete positive energy spectra and negative energy spectra are symmetric about zero energy for the case of a mixed vector and scalar kink-like potential coupling, and in the presence of constant mass this symmetry only appears for the cases of a pure scalar kink-like potential coupling or massless particles. (author)

151

Design, synthesis and experimental validation of novel potential chemopreventive agents using random forest and support vector machine binary classifiers.  

Science.gov (United States)

Compared to the current knowledge on cancer chemotherapeutic agents, only limited information is available on the ability of organic compounds, such as drugs and/or natural products, to prevent or delay the onset of cancer. In order to evaluate chemical chemopreventive potentials and design novel chemopreventive agents with low to no toxicity, we developed predictive computational models for chemopreventive agents in this study. First, we curated a database containing over 400 organic compounds with known chemoprevention activities. Based on this database, various random forest and support vector machine binary classifiers were developed. All of the resulting models were validated by cross validation procedures. Then, the validated models were applied to virtually screen a chemical library containing around 23,000 natural products and derivatives. We selected a list of 148 novel chemopreventive compounds based on the consensus prediction of all validated models. We further analyzed the predicted active compounds by their ease of organic synthesis. Finally, 18 compounds were synthesized and experimentally validated for their chemopreventive activity. The experimental validation results paralleled the cross validation results, demonstrating the utility of the developed models. The predictive models developed in this study can be applied to virtually screen other chemical libraries to identify novel lead compounds for the chemoprevention of cancers. PMID:24840854

Sprague, Brienne; Shi, Qian; Kim, Marlene T; Zhang, Liying; Sedykh, Alexander; Ichiishi, Eiichiro; Tokuda, Harukuni; Lee, Kuo-Hsiung; Zhu, Hao

2014-06-01

152

Bound states of the Klein-Gordon equation in D-dimensions with some physical scalar and vector exponential-type potentials including orbital centrifugal term  

OpenAIRE

The approximate analytic bound state solutions of the Klein-Gordon equation with equal scalar and vector exponential-type potentials including the centrifugal potential term are obtained for any arbitrary orbital angular momentum number l and dimensional space D. The relativistic/non-relativistic energy spectrum equation and the corresponding unnormalized radial wave functions, in terms of the Jacobi polynomials P_{n}^{({\\alpha},{\\beta})}(z), where {\\alpha}>-1, {\\beta}>-1 an...

Ikhdair, Sameer M.

2011-01-01

153

First report in italy of the exotic mosquito species Aedes (Finlaya koreicus, a potential vector of arboviruses and filariae  

Directory of Open Access Journals (Sweden)

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

Capelli Gioia

2011-09-01

154

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.

2013-01-01

155

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

156

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

157

A lentiviral vector with expression controlled by E2F-1: A potential tool for the study and treatment of proliferative diseases  

International Nuclear Information System (INIS)

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

158

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

2012-01-01

159

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

160

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.; Eisen, L.; Estes, M. G.; Estes, S. M.; Hayden, M.; Lozano-Fuentes, S.; Monaghan, A. J.; Moreno Madriñán, M. J.; Ochoa, C.; Quattrochi, D.; Tapia, B.; Welsh-Rodriguez, C. M.

2012-12-01

161

Zoom in at African country level: potential climate induced changes in areas of suitability for survival of malaria vectors  

OpenAIRE

Predicting anopheles vectors’ population densities and boundary shifts is crucial in preparing for malaria risks and unanticipated outbreaks. Although shifts in the distribution and boundaries of the major malaria vectors (Anopheles gambiae s.s. and An. arabiensis) across Africa have been predicted, quantified areas of absolute change in zone of suitability for their survival have not been defined. In this study, we have quantified areas of absolute change conducive for the establishment an...

Tonnang, Henri Ez; Tchouassi, David P.; Juarez, Henry S.; Igweta, Lilian K.; Djouaka, Rousseau F.

2014-01-01

162

Zoom in at African Country level: Potential Climate Induced Changes in Areas of Suitability for Survival of Malaria Vectors  

OpenAIRE

Predicting anopheles vectors’ population densities and boundary shifts is crucial in preparing for malaria risks and unanticipated outbreaks. Although shifts in the distribution and boundaries of the major malaria vectors (Anopheles gambiae s.s. and An. arabiensis) across Africa have been predicted, quantified areas of absolute change in zone of suitability for their survival have not been defined. In this study, we have quantified areas of absolute change conducive for the establishment an...

Tonnang, Henri Ez; Tchouassi, David P.; Juarez, Henry S.; Igweta, Lilian K.; Djouaka, Rousseau F.

2014-01-01

163

Confinement of spin-0 and spin-1/2 particles in a mixed vector-scalar coupling with unequal shapes for the potentials  

International Nuclear Information System (INIS)

The Klein-Gordon and the Dirac equations with vector and scalar potentials are investigated under a more general condition, Vv=Vs+constant. These isospectral problems are solved in the case of squared trigonometric potential functions and bound states for either particles or antiparticles are found. The eigenvalues and eigenfunctions are discussed in some detail. It is revealed that a spin-0 particle is better localized than a spin-1/2 particle when they have the same mass and are subjected to the same potentials

164

Potentiality of a New Minimum-Order Back-EMF State-Observer Taking Acceleration into Account for Sensorless Vector Control of Permanent-Magnet Synchronous Motors  

Science.gov (United States)

This paper proposes new sensorless vector control methods for permanent-magnet synchronous motors (PMSMs), which are based on a new minimum-order back-EMF state-observer taking acceleration into account, and examines potentiality of the improved back-EMF observer through experiments. Conventional sensorless vector control methods for PMSMs using an estimate of back-EMF are established under the assumption of constant speed or zero acceleration, consequently cannot operate properly at modes requiring rapid speed change especially in low speed region. On the other hand, the proposed back-EMF observer has the following features: 1) it is a new back-EMF state-observer taking acceleration into account and requiring no additional approximation to motor mathematical model; 2) it is a minimum order state-observer; 3) it utilizes motor parameters in the simplest manner; 4) it can be applied to both of salient-pole and non-salient-pole PMSMs; 5) it can be realized in both rotor and stator reference frames. Detailed designs and analyses for the improved state-observer and the sensorless vector control systems in both rotor and stator reference frames are given. In relation to the sensorless vector control systems, this paper newly proposes a double-integral type PLL method and an integral-feedback type acceleration/speed estimation method. Their potentialities are examined through experiments.

Shinnaka, Shinji; Saito, Yoji

165

Mapping the social network: tracking lice in a wild primate (Microcebus rufus population to infer social contacts and vector potential  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Studies of host-parasite interactions have the potential to provide insights into the ecology of both organisms involved. We monitored the movement of sucking lice (Lemurpediculus verruculosus, parasites that require direct host-host contact to be transferred, in their host population of wild mouse lemurs (Microcebus rufus. These lemurs live in the rainforests of Madagascar, are small (40 g, arboreal, nocturnal, solitary foraging primates for which data on population-wide interactions are difficult to obtain. We developed a simple, cost effective method exploiting the intimate relationship between louse and lemur, whereby individual lice were marked, without removal from their host, with an individualized code, and tracked throughout the lemur population. We then tested the hypotheses that 1 the frequency of louse transfers, and thus interactions, would decrease with increasing distance between paired individual lemurs; 2 due to host polygynandry, social interactions and hence louse transfers would increase during the onset of the breeding season; and 3 individual mouse lemurs would vary in their contributions to the spread of lice. Results We show that louse transfers involved 43.75% of the studied lemur population, exclusively males. Louse transfers peaked during the breeding season, perhaps due to increased social interactions between lemurs. Although trap-based individual lemur ranging patterns are restricted, louse transfer rate does not correlate with the distance between lemur trapping locales, indicating wider host ranging behavior and a greater risk of rapid population-wide pathogen transmission than predicted by standard trapping data alone. Furthermore, relatively few lemur individuals contributed disproportionately to the rapid spread of lice throughout the population. Conclusions Using a simple method, we were able to visualize exchanges of lice in a population of cryptic wild primates. This method not only provided insight into the previously unseen parasite movement between lemurs, but also allowed us to infer social interactions between them. As lice are known pathogen vectors, our method also allowed us to identify the lemurs most likely to facilitate louse-mediated epidemics. Our approach demonstrates the potential to uncover otherwise inaccessible parasite-host, and host social interaction data in any trappable species parasitized by sucking lice.

Zohdy Sarah

2012-03-01

166

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

Directory of Open Access Journals (Sweden)

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

167

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

168

Using remote sensing to map larval and adult populations of Anopheles hyrcanus (Diptera : Culicidae) a potential malaria vector in Southern France  

OpenAIRE

Background: Although malaria disappeared from southern France more than 60 years ago, suspicions of recent autochthonous transmission in the French Mediterranean coast support the idea that the area could still be subject to malaria transmission. The main potential vector of malaria in the Camargue area, the largest river delta in southern France, is the mosquito Anopheles hyrcanus ( Diptera: Culicidae). In the context of recent climatic and landscape changes, the evaluation of the risk of em...

Tran, Annelise; Poncon, Nicolas; Toty, Celine; Linard, Catherine; Guis, Helene; Ferre, Jean-baptiste; Lo Seen, Danny; Roger, Francois; La Rocque, Stephane; Fontenille, Didier; Baldet, Thierry

2008-01-01

169

Theileriosis (Cytauxzoonosis in Roan antelope (Hippotragus equinus: Field exposure to infection and identification of potential vectors  

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Full Text Available Four hand-reared, naïve roan antelope, 4 months of age, were exposed to naturally infected pasture on a game farm in Mpumalanga Province, South Africa, where roan are known to die from theileriosis. Various clinical parameters were recorded during this period. The predominant ticks parasitising these animals at the time (January to February, were Rhipicephalus appendiculatus and Rhipicephalus evertsi evertsi adults. After a period of 5?weeks the animals developed signs of clinical theileriosis and were treated with buparvaquone to prevent mortality. Primary hyperplasia of the local draining lymph nodes (Lnn. anorectales near the feeding site of adult R. evertsi evertsi indicated possible transmission of Theileria sp. (sable by this tick species. After recovery from theileriosis, these animals were confirmed carriers of Theileria sp. (sable by PCR (polymerase chain reaction and DNA probe analysis. Laboratory-bred larvae and nymphs of R. evertsi evertsi and R. appendiculatus respectively, were fed on the ears of these roan antelope. Salivary glands from moulted and prefed adult ticks of each species were dissected and stained for Theileria spp., and the PCR and DNA probe applied to a representative batch of dissected glands. R. appendiculatus adults collected from grass in infected camps were also dissected after prefeeding them on rabbits. Salivary glands of both tick species showed infected acini on staining and were also positive for Theileria sp. (sable only, on multiprotozoal PCR-screening analysis. There was no statistical significant difference between the infection rate and the intensity of infection between the two tick species. R. appendiculatus ticks collected from grass were also PCR-positive for Theileria sp. (sable.

How to cite this article: Steyl, J.C.A., Prozesky, L., Stoltsz, W.H. & Lawrence, J.A., 2012, ‘Theileriosis (Cytauxzoonosis in Roan antelope (Hippotragus equinus: Field exposure to infection and identification of potential vectors’, Onderstepoort Journal of Veterinary Research 79(1, Art. #367, 8 pages. http://dx.doi.org/10.4102/ojvr.v79i1.367

Johan C.A. Steyl

2012-02-01

170

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  

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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

171

Production of neutron cross section library based on JENDL-4.0 to continuous-energy Monte Carlo code MVP and its application to criticality analysis of benchmark problems in the ICSBEP handbook  

International Nuclear Information System (INIS)

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

172

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

173

Preconditioning techniques for constrained vector potential integral equations, with application to 3-D magnetoquasistatic analysis of electronic packages  

Energy Technology Data Exchange (ETDEWEB)

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

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

1994-12-31

174

Worldwide Niche and Future Potential Distribution of Culicoides imicola, a Major Vector of Bluetongue and African Horse Sickness Viruses  

OpenAIRE

We modelled the ecoclimatic niche of Culicoides imicola, a major arthropod vector of midge-borne viral pathogens affecting ruminants and equids, at fine scale and on a global extent, so as to provide insight into current and future risks of disease epizootics, and increase current knowledge of the species' ecology. Based on the known distribution and ecology of C. imicola, the species' response to monthly climatic conditions was characterised using CLIMEX with 10? spatial resolution climati...

Guichard, Sylvain; Guis, He?le?ne; Tran, Annelise; Garros, Claire; Balenghien, Thomas; Kriticos, Darren J.

2014-01-01

175

Mosquitos vetores potenciais de dirofilariose canina na Região Nordeste do Brasil Mosquitoes potential vectors of canine heartworm in the Northeast Region from Brazil  

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

Silvia MM Ahid

1999-12-01

176

ABCXYZ: vector potential (A) and magnetic field (B) code (C) for Cartesian (XYZ) geometry using general current elements. [In LRL TRAN for CDC > 600 computer  

Energy Technology Data Exchange (ETDEWEB)

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

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

1976-09-14

177

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

CERN Document Server

In this paper, spinor and vector decomposition 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 $\\phi$--mapping topological current theory. The topological charge of the knot is characterized by the Hopf indices and the Brouwer degrees of $\\phi$-mapping.

Duan Yi Shi; Li, Ran

2007-01-01

178

Using remote sensing to map larval and adult populations of Anopheles hyrcanus (Diptera: Culicidae a potential malaria vector in Southern France  

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Full Text Available Abstract Background Although malaria disappeared from southern France more than 60 years ago, suspicions of recent autochthonous transmission in the French Mediterranean coast support the idea that the area could still be subject to malaria transmission. The main potential vector of malaria in the Camargue area, the largest river delta in southern France, is the mosquito Anopheles hyrcanus (Diptera: Culicidae. In the context of recent climatic and landscape changes, the evaluation of the risk of emergence or re-emergence of such a major disease is of great importance in Europe. When assessing the risk of emergence of vector-borne diseases, it is crucial to be able to characterize the arthropod vector's spatial distribution. Given that remote sensing techniques can describe some of the environmental parameters which drive this distribution, satellite imagery or aerial photographs could be used for vector mapping. Results In this study, we propose a method to map larval and adult populations of An. hyrcanus based on environmental indices derived from high spatial resolution imagery. The analysis of the link between entomological field data on An. hyrcanus larvae and environmental indices (biotopes, distance to the nearest main productive breeding sites of this species i.e., rice fields led to the definition of a larval index, defined as the probability of observing An. hyrcanus larvae in a given site at least once over a year. Independent accuracy assessments showed a good agreement between observed and predicted values (sensitivity and specificity of the logistic regression model being 0.76 and 0.78, respectively. An adult index was derived from the larval index by averaging the larval index within a buffer around the trap location. This index was highly correlated with observed adult abundance values (Pearson r = 0.97, p An. hyrcanus larval and adult populations from the landscape indices. Conclusion This work shows that it is possible to use high resolution satellite imagery to map malaria vector spatial distribution. It also confirms the potential of remote sensing to help target risk areas, and constitutes a first essential step in assessing the risk of re-emergence of malaria in southern France.

Roger François

2008-02-01

179

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

180

A survey of mosquitoes breeding in used tires in Spain for the detection of imported potential vector species.  

Science.gov (United States)

The used tire trade has facilitated the introduction, spread, and establishment of the Asian tiger mosquito, Aedes albopictus, and other mosquito species in several countries of America, Africa, Oceania, and Europe. A strategy for detecting these imported mosquito vectors was developed in Spain during 2003-2004 by EVITAR (multidisciplinary network for the study of viruses transmitted by arthropods and rodents). A survey in 45 locations found no invasive species. Eight autochthonous species of mosquitoes were detected in used tires, including Culex pipiens, Cx. hortensis, Cx. modestus, Anopheles atroparvus, An. claviger, Culiseta longiareolata, Cs. annulata, and Aedes caspius. Dominant species were Cx. pipiens and Cs. longiareolata. Aedes caspius was found in only once, near its natural breeding habitat. Considering the recent discovery of an established population of Ae. albopictus in Catalonia, the increasing commerce of used tires in Spain for recycling, storage, and recapping might greatly contribute to the rapid spread of this species across the Iberian Peninsula. PMID:17633420

Roiz, D; Eritja, R; Escosa, R; Lucientes, J; Marquès, E; Melero-Alcíbar, R; Ruiz, S; Molina, R

2007-06-01

181

Identification of the natural breeding sites of sandflies (Diptera: Psychodidae: Phlebotominae), potential vectors of leishmaniasis, in the province of Chaco, Argentina  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The aim of this work was to identify the natural breeding sites of sandflies in the province of Chaco, Argentina, for the first time. Preliminary studies were conducted in two different phytogeographic regions: dry Chaco (Parque Provincial Pampa del Indio), in January 2010, and humid Chaco (Resisten [...] cia, Margarita Belén and Colonia Benítez), from May-September 2010. A total of 127 samples were collected (Pampa del Indio: 15, Resistencia: 37, Margarita Belén: 36, Colonia Benítez: 39). A female of Migonemyia migonei was found in Pampa del Indio at the base of a bromeliad in the summer (January) and a pupal exuvium of a phlebotomine fly was found in Resistencia, in a place where dogs rested, in the winter (July). These findings highlighted these two sites as potential breeding sites. Because the existence of potential natural breeding sites for sandflies has been demonstrated in both forest and periurban areas, expanding the search efforts and characterising these sites will enable the development of specific study designs to gain insight into the spatial distribution of the risks posed by these vectors. The resulting information will serve as a basis for proposing and evaluating vector control measures.

Matías Ariel, Parras; Juan Ramón, Rosa; Enrique Alejandro, Szelag; Oscar Daniel, Salomón.

2012-06-01

182

Amaranthus oleracea and Euphorbia hirta: natural potential larvicidal agents against the urban Indian malaria vector, Anopheles stephensi Liston (Diptera: Culicidae).  

Science.gov (United States)

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

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

2009-12-01

183

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

184

Vector analysis  

CERN Document Server

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

Newell, Homer E

2012-01-01

185

About vectors  

CERN Document Server

From his unusual beginning in ""Defining a vector"" to his final comments on ""What then is a vector?"" author Banesh Hoffmann has written a book that is provocative and unconventional. In his emphasis on the unresolved issue of defining a vector, Hoffmann mixes pure and applied mathematics without using calculus. The result is a treatment that can serve as a supplement and corrective to textbooks, as well as collateral reading in all courses that deal with vectors. Major topics include vectors and the parallelogram law; algebraic notation and basic ideas; vector algebra; scalars and scalar p

Hoffmann, Banesh

2012-01-01

186

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)

187

Comparative study of the effect of adriamycin on the sensitivity of mice to whole-body irradiation with 6-MVp photons or fast neutrons (67 MeV p ? Be)  

International Nuclear Information System (INIS)

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

188

Vectorization, parallelization and porting of nuclear codes (porting). 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 porting. In this porting part, the porting of Monte Carlo N-Particle Transport code MCNP4B2 and Reactor Safety Analysis code RELAP5 on the AP3000 are described. In the 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 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. (author)

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

2000-03-01

189

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

190

Synthesis, and Characterization, and Evaluation of Cellular Effects of the FOL-PEG-g-PEI-GAL Nanoparticles as a Potential Non-Viral Vector for Gene Delivery  

International Nuclear Information System (INIS)

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

191

The status and potential of new radionuclide generators providing positron emitters to synthesize new targeting vectors for PET  

International Nuclear Information System (INIS)

The 68Ge/Ga generator (68Ge, T1/2 = 270.8 d) provides a cyclotron independent source of positron emitting 68Ga (TT1/2 = 68 min, ??+ branching = 89%), which can be used for coordinative labelling. Recently, tumour imaging using 68Ga labelled DOTA conjugated peptides became one of the most exciting approaches to diagnose neuroendocrine and other tumours and metastases because (i) octreotide derivatives with high affinity and selectivity to somatostatin receptor expressing tumour cells are available, (ii) syntheses of DOTA conjugated targeting vectors are straightforward due to the kit type labelling, and (iii) PET/CT scanners perfectly correlate morphological and functional parameters. However, for labelling of biomolecules via bifunctional chelators, 68Ga(III) as eluted initially needs to be preconcentrated and purified from 68Ge(IV), Zn(II), Ti(IV) and Fe(III). The paper describes a system for the simple and efficient handling of the 68Ge/68Ga generator eluates with a microchromatography column filled with about 50 mg of a cation exchange resin. Chemical purification and volume concentration of 68Ga are carried out in an 80% acetone/0.15M HCl solution. Finally, more than 97% of 68Ga is obtained in 400 ?L of a 98% acetone/0.05M HCl solution. The initial 68Ge contamination of the eluate was reduced by a fnation of the eluate was reduced by a factor of 1000. Contents of Zn(II), Fe(III) and Ti(IV) were reduced significantly. Consequently, the processed fraction can be used directly for the synthesis of radiopharmaceuticals. The developed system represents a simple and efficient way of labelling DOTA conjugated biomolecules with generator produced 68Ga(III). [68Ga]DOTATOC and [68Ga]DOTANOC were successfully used in a series of human somatostatin receptor expressing tumour diagnoses with PET/CT. (author)

192

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

193

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

194

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

195

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

196

Vector inflation  

International Nuclear Information System (INIS)

We propose a scenario where inflation is driven by non-minimally coupled massive vector fields. In an isotropic homogeneous universe these fields behave in precisely the same way as a massive minimally coupled scalar field. Therefore our model is very similar to the model of chaotic inflation with a scalar field. For vector fields the isotropy of expansion is achieved either by considering a triplet of orthogonal vector fields or at the expense of N randomly oriented vector fields. In the latter case the substantial anisotropy of the expansion of order 1/?N survives until the end of inflation. The lightest vector fields might also force the late time acceleration of the universe

197

Vector financial rogue waves  

Energy Technology Data Exchange (ETDEWEB)

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

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

2011-11-21

198

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

199

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

200

Vector ecology of equine piroplasmosis.  

Science.gov (United States)

Equine piroplasmosis is a disease of Equidae, including horses, donkeys, mules, and zebras, caused by either of two protozoan parasites, Theileria equi or Babesia caballi. These parasites are biologically transmitted between hosts via tick vectors, and although they have inherent differences they are categorized together because they cause similar pathology and have similar morphologies, life cycles, and vector relationships. To complete their life cycle, these parasites must undergo a complex series of developmental events, including sexual-stage development in their tick vectors. Consequently, ticks are the definitive hosts as well as vectors for these parasites, and the vector relationship is restricted to a few competent tick species. Because the vector relationship is critical to the epidemiology of these parasites, we highlight current knowledge of the vector ecology of these tick-borne equine pathogens, emphasizing tick transmissibility and potential control strategies to prevent their spread. PMID:25564746

Scoles, Glen A; Ueti, Massaro W

2015-01-01

201

Viral vectors for malaria vaccine development.  

OpenAIRE

A workshop on viral vectors for malaria vaccine development, organized by the PATH Malaria Vaccine Initiative, was held in Bethesda, MD on October 20, 2005. Recent advancements in viral-vectored malaria vaccine development and emerging vector technologies were presented and discussed. Classic viral vectors such as poxvirus, adenovirus and alphavirus vectors have been successfully used to deliver malaria antigens. Some of the vaccine candidates have demonstrated their potential in inducing mal...

Li, S.; Locke, E.; Bruder, J.; Clarke, D.; Doolan, Dl; Havenga, Mj; Hill, Av; Liljestrom, P.; Monath, Tp; Naim, Hy; Ockenhouse, C.; Tang, Dc; Kampen, Kr; Viret, Jf; Zavala, F.

2007-01-01

202

Chromosomal plasticity and evolutionary potential in the malaria vector Anopheles gambiae sensu stricto: insights from three decades of rare paracentric inversions  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background In the Anopheles gambiae complex, paracentric chromosomal inversions are non-randomly distributed along the complement: 18/31 (58% of common polymorphic inversions are on chromosome arm 2R, which represents only ~30% of the complement. Moreover, in An. gambiae sensu stricto, 6/7 common polymorphic inversions occur on 2R. Most of these inversions are considered markers of ecological adaptation that increase the fitness of the carriers of alternative karyotypes in contrasting habitats. However, little is known about the evolutionary forces responsible for their origin and subsequent establishment in field populations. Results Here, we present data on 82 previously undescribed rare chromosomal inversions (RCIs recorded during extensive field sampling in 16 African countries over a 30 year period, which may shed light on the dynamics of chromosomal plasticity in An. gambiae. We analyzed breakpoint distribution, length, and geographic distribution of RCIs, and compared these measures to those of the common inversions. We found that RCIs, like common inversions, are disproportionately clustered on 2R, which may indicate that this arm is especially prone to breakages. However, contrasting patterns were observed between the geographic distribution of common inversions and RCIs. RCIs were equally frequent across biomes and on both sides of the Great Rift Valley (GRV, whereas common inversions predominated in arid ecological settings and west of the GRV. Moreover, the distribution of RCI lengths followed a random pattern while common inversions were significantly less frequent at shorter lengths. Conclusion Because 17/82 (21% RCIs were found repeatedly at very low frequencies – at the same sampling location in different years and/or in different sampling locations – we suggest that RCIs are subject mainly to drift under unperturbed ecological conditions. Nevertheless, RCIs may represent an important reservoir of genetic variation for An. gambiae in response to environmental changes, further testifying to the considerable evolutionary potential hidden within this pan-African malaria vector.

Torre Alessandra

2008-11-01

203

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

OpenAIRE

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 alt...

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

2014-01-01

204

Navigational Vectors  

Science.gov (United States)

This is a high school instructional unit that features nine lessons relating to vectors. Students build understanding of vector properties as they learn airplane navigation. Problem-based learning activities include reading real-time weather maps, tracking airplanes flying in U.S. skies, calculating vector components, analyzing effects of wind velocity, and completing training segments similar to a private pilot certification program. Participants have access to help from experts at the Polaris Career Center. Comprehensive teacher guides, student guides, reference materials, and assessments are included. This resource was developed by the Center for Innovation in Science and Engineering Education (CIESE). Participation is cost-free; additional options are available for registered users.

2008-12-10

205

Vector geometry  

CERN Document Server

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

Robinson, Gilbert de B

2013-01-01

206

Analysis of sample worth for Dy2O3, Ho2O3, Er2O3 and Tm2O3 measured at KUCA by MVP with recent version of JENDL, ENDF and JEFF  

International Nuclear Information System (INIS)

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

207

Evaluation of Multi Potential Bioactive Endod, Phytolacca dodecandra (L’ Herit) Berries Extracts Against Immature Filarial Vector Culex quinquefasciatus Say (Diptera: Culicidae)  

OpenAIRE

Aim of the present study was to evaluate larvicidal and pupicidal properties of Phytolacca dodecandra plant extracts against immature filarial vector, Culex quinquefasciatus. The powdered berries were extracted with petroleum ether, acetone, benzene, methanol and water. The crude residue obtained from the extraction was used to prepare 62.5, 125, 250, 500 and 1000 ppm concentration, respectively. The experiment was conducted by using standard WHO protocol with modifications. The immature mosq...

Nagappan Raja; Tigab Temesgen; Mamaye Tesera; Muche Tadele; Shiferaw Moges; Nurie Misganaw

2012-01-01

208

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

Directory of Open Access Journals (Sweden)

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

Tonja W. Fisher

2014-11-01

209

Comparison of potato and asian citrus psyllid adult and nymph transcriptomes identified vector transcripts with potential involvement in circulative, propagative liberibacter transmission.  

Science.gov (United States)

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

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

2014-01-01

210

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

Directory of Open Access Journals (Sweden)

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

M Charalambous

1997-03-01

211

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.

1997-03-01

212

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)

213

Vector BPS baby Skyrme model  

Science.gov (United States)

We investigate the relation between the Bogomol’nyi-Prasad-Sommerfeld (BPS) baby Skyrme model and its vector meson formulation, where the baby Skyrme term is replaced by a coupling between the topological current B? and the vector meson field ??. The vector model still possesses infinitely many symmetries leading to infinitely many conserved currents which stand behind its solvability. It turns out that the similarities and differences of the two models depend strongly on the specific form of the potential. We find, for instance, that compactons (which exist in the BPS baby Skyrme model) disappear from the spectrum of solutions of the vector counterpart. Specifically, for the vector model with the old baby Skyrme potential we find that it has compacton solutions only provided that a delta function source term effectively screening the topological charge is inserted at the compacton boundary. For the old baby Skyrme potential squared we find that the vector model supports exponentially localized solitons, like the BPS baby Skyrme model. These solitons, however, saturate a BPS bound which is a nonlinear function of the topological charge and, as a consequence, higher solitons are unstable with respect to decay into smaller ones, which is at variance with the more conventional situation (a linear BPS bound and stable solitons) in the BPS baby Skyrme model.

Adam, C.; Naya, C.; Sanchez-Guillen, J.; Wereszczynski, A.

2012-08-01

214

New Constitutive Vectors: Useful Genetic Engineering Tools for Biocatalysis  

OpenAIRE

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

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

2013-01-01

215

Vector fields in cosmology  

CERN Document Server

Vector fields can arise in the cosmological context in different ways, and we discuss both abelian and nonabelian sector. In the abelian sector vector fields of the geometrical origin (from dimensional reduction and Einstein-Eddington modification of gravity) can provide a very non-trivial dynamics, which can be expressed in terms of the effective dilaton-scalar gravity with the specific potential. In the non-abelian sector we investigate the Yang-Mills SU(2) theory which admits isotropic and homogeneous configuration. Provided the non-linear dependence of the lagrangian on the invariant F*F(dual), one can obtain the inflationary regime with the exponential growth of the scale factor. The effective amplitudes of the 'electric' and 'magnetic' components behave like slowly varying scalars at this regime, what allows the consideration of some realistic models with non-linear terms in the Yang-Mills lagrangian.

Davydov, Evgeny

2011-01-01

216

The vector BPS baby Skyrme model  

CERN Document Server

We investigate the relation between the BPS baby Skyrme model and its vector meson formulation, where the baby Skyrme term is replaced by a coupling between the topological current $B_\\mu$ and the vector meson field $\\omega_\\mu$. The vector model still possesses infinitely many symmetries leading to infinitely many conserved currents which stand behind its solvability. It turns out that the similarities and differences of the two models depend strongly on the specific form of the potential. We find, for instance, that compactons (which exist in the BPS baby Skyrme model) disappear from the spectrum of solutions of the vector counterpart. Specifically, for the vector model with the old baby Skyrme potential we find that it has compacton solutions only provided that a delta function source term effectively screening the topological charge is inserted at the compacton boundary. For the old baby Skyrme potential squared we find that the vector model supports exponentially localized solitons, like the BPS baby Sky...

Adam, C; Sanchez-Guillen, J; Wereszczynski, A

2012-01-01

217

Helper-Dependent Adenoviral Vectors.  

Science.gov (United States)

Helper-dependent adenoviral vectors are devoid of all viral coding sequences, possess a large cloning capacity, and can efficiently transduce a wide variety of cell types from various species independent of the cell cycle to mediate long-term transgene expression without chronic toxicity. These non-integrating vectors hold tremendous potential for a variety of gene transfer and gene therapy applications. Here, we review the production technologies, applications, obstacles to clinical translation and their potential resolutions, and the future challenges and unanswered questions regarding this promising gene transfer technology. PMID:24533227

Rosewell, Amanda; Vetrini, Francesco; Ng, Philip

2011-10-29

218

Evaluation of Multi Potential Bioactive Endod, Phytolacca dodecandra (L’ Herit Berries Extracts Against Immature Filarial Vector Culex quinquefasciatus Say (Diptera: Culicidae  

Directory of Open Access Journals (Sweden)

Full Text Available Aim of the present study was to evaluate larvicidal and pupicidal properties of Phytolacca dodecandra plant extracts against immature filarial vector, Culex quinquefasciatus. The powdered berries were extracted with petroleum ether, acetone, benzene, methanol and water. The crude residue obtained from the extraction was used to prepare 62.5, 125, 250, 500 and 1000 ppm concentration, respectively. The experiment was conducted by using standard WHO protocol with modifications. The immature mosquitoes were exposed to selected concentration and the percentage mortality was observed continuously for 12, 24 and 48 h, respectively. Among the various solvent extracts tested, petroleum ether, acetone and benzene showed maximum mortality at 125 ppm concentration and above. At 1000 ppm concentration, all the solvent extracts tested showed 100% mortality. The III-instar larva was highly susceptible compared to IV-instar and pupa. The water and methanol extract was also proved to have larvicidal and pupicidal properties. This study showed P. dodecandra plant extract have bioactivity compound to kill the immature Cx. quinquefasciatus. These plants are growing naturally in Ethiopian highlands and proper utilization may prevent unwanted pollution to the environment.

Nagappan Raja

2012-07-01

219

The Anopheles arabiensis genetic sexing strain ANO IPCL1 and its application potential for the sterile insect technique in integrated vector management programmes.  

Science.gov (United States)

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

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

2015-02-01

220

A low-cost mesocosm for the study of behaviour and reproductive potential in Afrotropical mosquito (Diptera: Culicidae) vectors of malaria.  

Science.gov (United States)

A large-scale mesocosm was constructed and tested for its effectiveness for use in experiments on behaviour, reproduction and adult survivorship in the Afrotropical malaria vector Anopheles gambiae s.s. Giles (Diptera: Culicidae) in temperate climates. The large space (82.69 m(3) ) allowed for semi-natural experiments that increased demand on a mosquito's energetic reserves in an environment of widely distributed resources. A one-piece prefabricated enclosure, made with white netting and vinyl, prevented the ingress of predators and the egress of mosquitoes. Daylight and white materials prompted the mosquitoes to seclude themselves in restricted daytime resting sites and allowed the easy collection of dead bodies so that daily mortality could be assessed accurately using a method that accounts for the loss of a proportion of bodies. Here, daily, age-dependent mortality rates of males and females were estimated using Bayesian Markov chain Monte Carlo simulation. In overnight experiments, mosquitoes successfully located plants and took sugar meals. A 3-week survival trial with a single cohort demonstrated successful mating, blood feeding, oviposition and long life. The relatively low cost of the mesocosm and the performance of the mosquitoes in it make it a viable option for any behavioural or ecological study of tropical mosquitoes in which space and seasonal cold are constraining factors. PMID:25294339

Jackson, B T; Stone, C M; Ebrahimi, B; Briët, O J T; Foster, W A

2015-03-01

221

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  

Directory of Open Access Journals (Sweden)

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

Adrias Araceli Q

2010-05-01

222

Gene therapy using retroviral vectors.  

Science.gov (United States)

Gene therapy is a novel approach for treating various congenital and acquired genetic disorders, including cancer, heart disease, and acquired immune deficiency syndrome. Amongst possible gene delivery systems, retroviral vector mediated gene transfer has been the most extensively studied and has been approved for use in over 40 current Phase I/II clinical trials for the treatment of various disorders, primarily cancers. Recent technological improvements include the optimization of vector production by concentration and lyophilization, resulting in high titers of vectors, as well as the large-scale production of vector-produced cells for the treatment of brain cancer. Present clinical protocols require specialized care centers with expertise in molecular biology and cell transplantation. Considerable effort is under way to develop retroviral vectors that can be both injected directly into the body and targeted to specific cell types within the body. Such vectors could be administered to patients by physicians in their offices. Successful development of this new technology would greatly expand the clinical potential of gene therapy. PMID:7765744

Gordon, E M; Anderson, W F

1994-12-01

223

Emerging Vector-Borne Diseases – Incidence through Vectors  

Science.gov (United States)

Vector-borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowadays, in intercontinental countries, there is a struggle with emerging diseases, which have found their way to appear through vectors. Vector-borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens, and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector-borne infectious diseases and disease outbreaks. It could affect the range and population of pathogens, host and vectors, transmission season, etc. Reliable surveillance for diseases that are most likely to emerge is required. Canine vector-borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, and leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fundamental role at primarily prevention and then treatment of vector-borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases. During a 4-year period, from 2009 to 2013, a total number of 551 dog samples were analyzed for vector-borne diseases (borreliosis, babesiosis, ehrlichiosis, anaplasmosis, dirofilariosis, and leishmaniasis) in routine laboratory work. The analysis was done by serological tests – ELISA for borreliosis, dirofilariosis, and leishmaniasis, modified Knott test for dirofilariosis, and blood smear for babesiosis, ehrlichiosis, and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on average more then half of the samples brought to the laboratory to analysis for different infectious diseases are analyzed for vector-borne diseases. In the region of Vojvodina (northern part of Serbia), the following vector-borne infectious diseases have been found in dogs so far borreliosis, babesiosis, dirofilariosis, leishmaniasis, and anaplasmosis. PMID:25520951

Savi?, Sara; Vidi?, Branka; Grgi?, Zivoslav; Potkonjak, Aleksandar; Spasojevic, Ljubica

2014-01-01

224

Vector-Borne Diseases  

Science.gov (United States)

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

Harvey Artsob

225

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.

2008-12-01

226

Analysis of sample worth for Dy2O3, Ho2O3, Er2O3 and Tm2O3 measured at KUCA by MVP with recent version of ENDF and JENDL  

International Nuclear Information System (INIS)

Analyses were performed to verify nuclear data of some rare-earth elements by using the continuous energy Monte-Carlo code: MVP with recent version of ENDF and JENDL. The target of the analysis is the sample worth of Dy2O3, Ho2O3, Er2O3 and Tm2O3 measured at Kyoto University Critical Assembly (KUCA), and the worth was measured at two different cores named E3 (softer neutron spectrum) and EE1 (harder neutron spectrum) to evaluate the dependency of C/E values on neutron spectrum. The cross section library such as JENDL-3.3 does not cover all of four elements, therefore the sample worth of Dy2O3 and Ho2O3 was analyzed with ENDF/B-VI.8 and ENDF/B-VII.0, and that of Er2O3 was analyzed with ENDF/B-VI.8, ENDF/B-VII.0 and JENDL-3.3, and that of Tm2O3 was analyzed with the preliminary version of JENDL-4 which was specially processed at JAEA. The C/E values are within the range from 0.94 to 1.13 with relative standard deviation about 0.03. The analysis with preliminary version of JENDL-4 for Tm is also in good agreement with the measurements and the C/E values are about 0.98 for both E3 and EE1 cores. These results indicate the validity of cross section data in the library, however relatively large dependency on neutron spectrum is observed for Er2O3 with JENDL-3.3 (C/E values are 1.>3 with JENDL-3.3 (C/E values are 1.07 at E3 and 0.94 at EE1) and for Ho2O3 with ENDF/B-VI.8 (C/E values are 1.10 at E3 and 0.99 at EE1). (author)

227

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

Directory of Open Access Journals (Sweden)

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

Spinner Justin L

2012-12-01

228

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

229

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

230

Sequential administration of bovine and human adenovirus vectors to overcome vector immunity in an immunocompetent mouse model of breast cancer  

OpenAIRE

The potential of a bovine adenovirus serotype 3 (BAd3)-based vector to bypass the human adenoviral serotype 5 (HAd5)-specific neutralizing immune response was evaluated in an immunocompetent mouse model of breast cancer. Initially we monitored vector biodistribution, genome persistence, transgene expression, and potential toxicity of HAd-GFP [HAd5 vector expressing green fluorescent protein (GFP)] or BAd-GFP (BAd3 vector expressing GFP) in FVB/n mice bearing tumors. A comparable biodistributi...

Tandon, Manish; Sharma, Anurag; Vemula, Sai V.; Bangari, Dinesh S.; Mittal, Suresh K.

2011-01-01

231

Production of high-capacity adenovirus vectors.  

Science.gov (United States)

High-capacity adenoviral vectors (HC-Ad), also known as "helper-dependent" (HD-Ad), "gutless", "gutted", or "third-generation" Ad vectors, are devoid of all viral coding sequences and have shown promising potential for a wide variety of different applications-from classic gene therapy to genetic vaccination and tumor treatment. However, compared to first-generation adenoviral vectors their production is more complex and requires specific in-depth knowledge. This chapter delivers a detailed protocol for the successful production of HC-Ad vectors to high titers. PMID:24132488

Kreppel, Florian

2014-01-01

232

[Late ventricular potentials and mitral valve prolapse].  

Science.gov (United States)

In order to determine the predictive value for ventricular arrhythmias of ventricular late potentials (LP) in mitral valve prolapse (MVP) the authors performed high amplification signal-averaging ECG (SA) and 24 hours ambulatory ECG (Holter) monitoring in 68 consecutive patients (34 men, 34 women, average age 48 +/- 17.7 years) with echocardiographically diagnosed MVP. Patients with bundle branch block or associated cardiac disease were excluded. Echocardiography showed 26 patients to have floppy mitral valves (38.2%), 50 patients to have posterior deplacement > or = 5 mm of the mitral valves in systole (73.5%) and 35 patients to have mitral regurgitation (51.4%). Holter monitoring showed 17 patients without ventricular extrasystoles (VES), 15 had Lown Grade I, 6 had Lown Grade II, 3 had Lown Grade III, 15 had Lown Grade IV A and 12 had Lown Grade IV B ventricular arrhythmias. Therefore, 30 patients had complex ventricular arrhythmias (> or = Lown Grade III) and 13 patients had spontaneous non-sustained ventricular tachycardia (NSVT) (one patient had NSVT on resting ECG but not on Holter monitoring). Eighteen patients had LP (26.5%). The incidence of complex ventricular arrhythmias was higher in patients with mitral regurgitation (62.8% versus 27.7%; p < 0.005) whereas the incidence of NSVT was not significantly different (25.7% versus 17.1%; p = 0.15). On the other hand, the frequency of complex ventricular arrhythmias was not significantly different in the presence or absence of LP (61.1% versus 40%: NS) whereas the incidence of NSVT was higher in patients with LP (44.4% versus 10%; p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7832621

Babuty, D; Charniot, J C; Delhomme, C; Fauchier, L; Fauchier, J P; Cosnay, P

1994-03-01

233

Single-particle states in 59Ni with 58Ni( vector d, p)59Ni reaction at 56 MeV and neutron-bound-state complex potentials  

International Nuclear Information System (INIS)

Angular distributions of the cross sections and analyzing powers were measured for the 58Ni(d,p)59Ni reaction up to the excitation energy of 10 MeV in 59Ni with a high-resolution polarized deuteron beam at 56 MeV. Spins and parities were assigned for 33 discrete levels up to the excitation energy of 8 MeV. Spectroscopic factors, single-particle energies and spreading widths of 1f5/2, 2p3/2, 2p1/2, 1g9/2 states were obtained. Neutron-bound-state complex potentials have been calculated from the resultant spreading widths and energies together with results from other one-nucleon transfer-reaction experiments on nickel and calcium isotopes. It is found that the energy dependence of the spreading widths of the single-particle and -hole states and then the imaginary parts of the bound-state potentials in the excitation energy region of 0-10 MeV show a symmetrical behavior with respect to the Fermi surface. ((orig.))

234

Vector bundles on toric varieties  

CERN Document Server

Following Sam Payne's work, we study the existence problem of nontrivial vector bundles on toric varieties. The first result we prove is that every complete fan admits a nontrivial conewise linear multivalued function. Such functions could potentially be the Chern classes of toric vector bundles. Then we use the results of Corti\\~nas, Haesemeyer, Walker and Weibel to show that the (non-equivariant) Grothendieck group of the toric 3-fold studied by Payne is large, so the variety has a nontrivial vector bundle. Using the same computation, we show that every toric 3-fold X either has a nontrivial line bundle, or there is a finite surjective toric morphism from Y to X, such that Y has a large Grothendieck group.

Gharib, Saman

2011-01-01

235

Light axial vector mesons  

CERN Document Server

Inspired by the abundant experimental observation of axial vector states, we study whether the observed axial vector states can be categorized into the conventional axial vector meson family. In this paper we carry out analysis based on the mass spectra and two-body Okubo-Zweig-Iizuka-allowed decays. Besides testing the possible axial vector meson assignments, we also predict abundant information for their decays and the properties of some missing axial vector mesons, which are valuable to further experimental exploration of the observed and predicted axial vector mesons.

Chen, Kan; Liu, Xiang; Matsuki, Takayuki

2015-01-01

236

Biofabrication of Ag nanoparticles using Sterculia foetida L. seed extract and their toxic potential against mosquito vectors and HeLa cancer cells.  

Science.gov (United States)

A one-step and eco-friendly process for the synthesis of silver-(protein-lipid) nanoparticles (Ag-PL NPs) (core-shell) has been developed using the seed extract from wild Indian Almond tree, Sterculia foetida (L.) (Sterculiaceae). The reaction temperature played a major role in controlling the size and shell formation of NPs. The amount of NPs synthesized and qualitative characterization was done by UV-vis spectroscopy and transmission electron microscopy (TEM), respectively. TEM studies exhibited controlled dispersity of spherical shaped NPs with an average size of 6.9±0.2nm. Selected area electron diffraction (SAED) and X-ray diffraction (XRD) revealed 'fcc' phase and crystallinity of the particles. X-ray photoelectron spectroscopy (XPS) was used to identify the protein-lipid (PL) bilayer that appears as a shell around the Ag core particles. The thermal stability of the Ag-PL NPs was examined using thermogravimetric analysis (TGA). Further analysis was carried out by using Fourier transform infrared spectroscopy (FTIR), where the spectra provided evidence for the presence of proteins and lipid moieties ((2n-octylcycloprop-1-enyl)-octanoic acid (I)), and their role in synthesis and stabilization of Ag NPs. This is the first report of plant seed assisted synthesis of PL conjugated Ag NPs. These formed Ag-PL NPs showed potential mosquito larvicidal activity against Aedes aegypti (L.), Anopheles stephensi Liston and Culex quinquefasciatus Say. These Ag-PL NPs can also act as promising agents in cancer therapy. They exhibited anti-proliferative activity against HeLa cancer cell lines and a promising toxicity was observed in a dose dependent manner. Toxicity studies were further supported by the cellular DNA fragmentation in the Ag-PL NPs treated HeLa cells. PMID:24863217

Rajasekharreddy, Pala; Rani, Pathipati Usha

2014-06-01

237

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

238

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

239

Subretinal gene delivery using helper-dependent adenoviral vectors  

OpenAIRE

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; Lam Simon; Cao Huibi; Guan Rui; Duan Rongqi; van der Kooy Derek; Bremner Rod; Molday Robert S; Hu Jim

2011-01-01

240

Subretinal gene delivery using helper-dependent adenoviral vectors.  

Science.gov (United States)

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. PMID:21711866

Wu, Linda; Lam, Simon; Cao, Huibi; Guan, Rui; Duan, Rongqi; van der Kooy, Derek; Bremner, Rod; Molday, Robert S; Hu, Jim

2011-01-01

241

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

242

Deterministic Vector Freak Waves  

CERN Document Server

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

Baronio, Fabio; Conforti, Matteo; Wabnitz, Stefan

2012-01-01

243

Generalization of concurrence vectors  

International Nuclear Information System (INIS)

In this Letter, based on the generalization of concurrence vectors for bipartite pure state with respect to employing tensor product of generators of the corresponding rotation groups, we generalize concurrence vectors to the case of mixed states; a new criterion of separability of multipartite pure states is given out, for which we define a concurrence vector; we generalize the vector to the case of multipartite mixed state and give out a good measure of free entanglement

244

Switched Multistage Vector Quantizer  

OpenAIRE

This paper investigates the use of a new hybrid vector quantizer called Switched Multi stage vector quantization (SWMSVQ) technique using hard and soft decision schemes, for coding of narrow band speech signals. This technique is a hybrid of Switch vector quantization technique and Multi stage vector quantization technique. SWMSVQ quantizes the linear predictive coefficients (LPC) in terms of the line spectral frequencies (LSF). The spectral distortion performance, computational complexity an...

Satya Sai Ram, M.; Siddaiah, Dr P.; Madhavi Latha, Dr M.

2010-01-01

245

Advances of Lentiviral Vectors  

Directory of Open Access Journals (Sweden)

Full Text Available Lentiviral vectors are currently very effective tools in molecular and cell experiment. Lentiviral vector, a kind of retroviral vectors, has a number of unique advantages in target gene transferation, for example, the ability of transfection to the dividing or nondividing cells, its high efficiency of transfection and a capacity of large target gene fragments. This paper describes the sources of lentiviral vectors, molecular characteristics, research progress, etc.

Fanrong MENG

2014-12-01

246

Rotations with Rodrigues' vector  

International Nuclear Information System (INIS)

The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears to be a fundamental matrix that is used to express the components of the angular velocity, the rotation matrix and the angular momentum vector. The Hamiltonian formalism of rotational dynamics in terms of this vector uses the same matrix. The quantization of the rotational dynamics is performed with simple rules if one uses Rodrigues' vector and similar formal expressions for the quantum operators that mimic the Hamiltonian classical dynamics.

247

Alphavirus vectors as recombinant vaccines  

OpenAIRE

ALPHAVIRUS VECTORS AS RECOMBINANT VACCINES Peter Berglund Doctoral dissertation from the Microbiology and TumorbiologyCenter Karolinska Institute, Sweden This thesis describes further developments of an expression system based on thealphavirus Semliki Forest virus (SFV), and its potential use as recombinant vaccine. The RNA genome of SFV contains a 3'open reading frame (ORF) encoding the structuralproteins, and a 5' ORF coding for the viral replicase. Transfecti...

Berglund, Peter

1997-01-01

248

The midgut transcriptome of Phlebotomus (Larroussius perniciosus, a vector of Leishmania infantum: comparison of sugar fed and blood fed sand flies  

Directory of Open Access Journals (Sweden)

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

Valenzuela Jesus G

2011-05-01

249

Clifford Fourier transform on vector fields.  

Science.gov (United States)

Image processing and computer vision have robust methods for feature extraction and the computation of derivatives of scalar fields. Furthermore, interpolation and the effects of applying a filter can be analyzed in detail and can be advantages when applying these methods to vector fields to obtain a solid theoretical basis for feature extraction. We recently introduced the Clifford convolution, which is an extension of the classical convolution on scalar fields and provides a unified notation for the convolution of scalar and vector fields. It has attractive geometric properties that allow pattern matching on vector fields. In image processing, the convolution and the Fourier transform operators are closely related by the convolution theorem and, in this paper, we extend the Fourier transform to include general elements of Clifford Algebra, called multivectors, including scalars and vectors. The resulting convolution and derivative theorems are extensions of those for convolution and the Fourier transform on scalar fields. The Clifford Fourier transform allows a frequency analysis of vector fields and the behavior of vector-valued filters. In frequency space, vectors are transformed into general multivectors of the Clifford Algebra. Many basic vector-valued patterns, such as source, sink, saddle points, and potential vortices, can be described by a few multivectors in frequency space. PMID:16138556

Ebling, Julia; Scheuermann, Gerik

2005-01-01

250

Implicit Real Vector Automata  

Directory of Open Access Journals (Sweden)

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

Jean-François Degbomont

2010-10-01

251

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

252

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.

253

Seasonal abundance and epidemiological indices of potential plague vectors Dinopsyllus lypusus (Siphonaptera: Hystrichopsyllidae) and Ctenophthalmus calceatus (Siphonaptera: Ctenophthalmidae) on rodents captured from three habitat types of Hatcliffe and Dzivarasekwa suburbs of Harare, Zimbabwe.  

Science.gov (United States)

The seasonal abundance of Dinopsyllus lypusus Jordan and Rothschild and Ctenophthalmus calceatus Waterson (potential vectors of plague in southern Africa) were studied on rodent hosts captured in selected habitat types of two periurban suburbs of Harare, Zimbabwe. Removal trapping was used to capture the rodents, from which fleas were collected and identified. Prevalence (proportion of animals infested) and specific flea index (SFI = number of fleas per animal) were calculated for each species of rodent host. Cohabitation of the two flea species on the host and its implications were also assessed. In total, 1,083 rodents belonging to nine species were trapped and over 97% of the total captures comprised of four species; Mastomys natalensis Smith, Rattus rattus L., Tatera leucogaster Peters, and Rhabdomys pumilio Sparrman. In total, 735 D. lypusus and 335 C. calceatus were recorded on these four common rodent species. Population density of D. lypusus as measured by prevalence and SFI varied from 13.4 to 53.3% and 0.2-1.5, respectively, while that of C. calceatus varied from 8.2 to 26.7% and 0.2-0.6, respectively. For all rodent species captured, both prevalence and SFI of D. lypusus and C. calceatus were highest during the cold-dry season, followed by the hot dry season, with the hot-wet season recording the lowest indices. Overall cohabitation was highest during the cold-dry season and nonexistent during the hot-wet season. Our findings on the abundance and ecology of D. lypusus and C. calceatus suggest that their roles in the transmission of plague in Zimbabwe need further investigation. PMID:23270175

Zimba, Moses; Loveridge, John; Pfukenyi, Davies M; Mukaratirwa, Samson

2012-11-01

254

Magnetic vector aftereffect model  

Science.gov (United States)

In addition to the decay of magnetization with time that occurs in scalar processes, in vector processes the magnetization must also rotate toward the easy axis. In this model, each hysteron is characterized by a critical surface. The energy of the hysteron is proportional to the size of the difference between the applied field and the particular point on the critical surface. An energy landscape is obtained by plotting the size of this difference as a function of magnetization angle. The equilibrium state is one in which the hysterons lie in the potential wells with a density given by Maxwell-Boltzmann statistics at room temperature. The logarithm of the time constant of the approach to equilibrium for a particular hysteron is given by the ratio of the barrier energy to the product of the absolute temperature and Boltzmann's constant. This barrier energy is obtained by the difference of the nearest maximum to the well depth. The overall behavior is the sum of this effect for all the hysterons.

Torre, E. Della; Cardelli, E.

2011-04-01

255

Vector generator scan converter  

Science.gov (United States)

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

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

1990-01-01

256

On cosmic inflation in vector field theories  

International Nuclear Information System (INIS)

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

257

On cosmic inflation in vector field theories  

Science.gov (United States)

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

Golovnev, Alexey

2011-12-01

258

On cosmic inflation in vector field theories  

CERN Document Server

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

Golovnev, Alexey

2011-01-01

259

The vector BPS Skyrme model  

CERN Document Server

We analyze the vector meson formulation of the BPS Skyrme model in (3+1) dimensions, where the term of sixth power in first derivatives characteristic for the original, integrable BPS Skyrme model (the topological or baryon current squared) is replaced by a coupling between the vector meson $\\omega_\\mu$ and the baryon current. We find that the model remains integrable in the sense of generalized integrability and almost solvable (reducible to a set of two first order ODEs) for any value of the baryon charge. Further, we analyze the appearance of topological solitons for two one-parameter families of one vacuum potentials: the old Skyrme potentials and the so-called BPS potentials. Depending on the value of the parameters we find several qualitatively different possibilities. In the massless case we have a parameter region with no skyrmions, a unique compact skyrmion with a discontinuous first derivative at the boundary (equivalently, with a source term located at the boundary, which screens the topological ch...

Adam, C; Sanchez-Guillen, J; Wereszczynski, A

2012-01-01

260

MAC^3: Vectors Worksheet  

Science.gov (United States)

This page contains a worksheet on the topic of vectors for beginning physics students. It was developed as a companion to the lecture presentations by the same authors (see Related Items on this page for a link.) A primary goal of the full instructional unit is to help physics and calculus students differentiate the uses of vectors for physics vs. mathematics, a difficulty known as the "vector calculus gap". This resource is part of a collection developed by the NSF-funded Mathematics Across the Community College Curriculum (MAC 3).

Friesen, Larry; Gillis, Anne

2008-12-22

261

Retroviral vectors for gene transfer.  

Science.gov (United States)

INTRODUCTIONRetroviral vectors from the ?-retrovirus genus were the first retroviral vectors to be developed. They have been called oncoretroviral vectors or simple retroviral vectors because of their derivation from oncogenic retroviruses having a simple gag-pol-env genome structure. Later additions to the retroviral vector family include the lentiviral and foamy viral vectors derived from more complex retroviruses that contain multiple accessory genes in addition to the standard gag-pol-env genes. This article describes the advantages and disadvantages of retroviral vectors for gene therapy. It also discusses the issues that must be considered in designing retroviral vectors and in choosing retroviral packaging cell lines. PMID:21356814

Cornetta, Kenneth; Pollok, Karen E; Miller, A Dusty

2008-01-01

262

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

OpenAIRE

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

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

2009-01-01

263

Resources and Vectors  

SCPinfonet

This theme will explore the current and future roles of different resources and \\energy vectors in the UK energy system. Its scope includes renewable and non-\\renewable resources: fossil fuels, critical materials and renewable ... Connect \\with us.

264

Dynamic vector hysteresis modeling  

Energy Technology Data Exchange (ETDEWEB)

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

Fuezi, Janos [Neutron Spectroscopy Department, Research Institute for Solid State Physics and Optics, H-1525 Budapest (Hungary) and Electrical Engineering Department, Transylvania University, Brasov (Romania)]. E-mail: fuzi@szfki.hu

2006-02-01

265

Dynamic vector hysteresis modeling  

International Nuclear Information System (INIS)

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

266

Kernelizing Vector Quantization Algorithms  

OpenAIRE

The kernel trick is a well known approach allowing to implicitly cast a linear method into a nonlinear one by replacing any dot product by a kernel function. However few vector quantization algorithms have been kernelized. Indeed, they usually imply to compute linear transformations (e.g. moving prototypes), what is not easily kernelizable. This paper introduces the Kernel-based Vector Quantization (KVQ) method which allows working in an approximation of the feature space, and thus kernelizin...

Geist, Matthieu; Pietquin, Olivier; Fricout, Gabriel

2009-01-01

267

Generalizing the Poynting Vector  

Science.gov (United States)

A very general energy conservation law derived from a Lagrangian theory of dielectric crystals is presented. It includes energy propagation from electromagnetic, spin, and acoustic waves. Both linear and nonlinear waves are included as well as various polaritonic combinations. Waves involving nonlocal (wave-vector-dispersive) interactions are also included. An example of the latter for which the Poynting vector is invalid, but which is correctly handled by this theory, is presented.

Nelson, D. F.

1996-06-01

268

Support vector machines applications  

CERN Document Server

Support vector machines (SVM) have both a solid mathematical background and good performance in practical applications. This book focuses on the recent advances and applications of the SVM in different areas, such as image processing, medical practice, computer vision, pattern recognition, machine learning, applied statistics, business intelligence, and artificial intelligence. The aim of this book is to create a comprehensive source on support vector machine applications, especially some recent advances.

Guo, Guodong

2014-01-01

269

Darboux Integrals for Schrödinger Planar Vector Fields via Darboux Transformations  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper we study the Darboux transformations of planar vector fields of Schrödinger type. Using the isogaloisian property of Darboux transformation we prove the ''invariance'' of the objects of the ''Darboux theory of integrability''. In particular, we also show how the shape invariance property of the potential is important in order to preserve the structure of the transformed vector field. Finally, as illustration of these results, some examples of planar vector fields coming from supersymmetric quantum mechanics are studied.

Primitivo B. Acosta-Humánez

2012-07-01

270

Viral Paratransgenesis in the Malaria Vector Anopheles gambiae  

OpenAIRE

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

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

2008-01-01

271

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

272

Foamy virus vectors for gene transfer.  

Science.gov (United States)

Foamy virus (FV) vectors are efficient gene delivery vehicles that have shown great promise for gene therapy in preclinical animal models. FVs or spumaretroviruses are not endemic in humans, but are prevalent in nonhuman primates and in other mammals. They have evolved means for efficient horizontal transmission in their host species without pathology. FV vectors have several unique properties that make them well suited for therapeutic gene transfer including a desirable safety profile, a broad tropism, a large transgene capacity, and the ability to persist in quiescent cells. They mediate efficient and stable gene transfer to hematopoietic stem cells (HSCs) in mouse models, and in the canine large animal model. Analysis of FV vector integration sites in vitro and in hematopoietic repopulating cells shows they have a unique integration profile, and suggests they may be safer than gammaretroviruses or lentiviral vectors. Here, properties of FVs relevant to the safety and efficacy of FV vectors are discussed. The development of FV vector systems is described, and studies evaluating their potential in vitro, and in small and large animal models, is reviewed. PMID:19743892

Trobridge, Grant D

2009-11-01

273

Sindbis viral vectors target hematopoietic malignant cells.  

Science.gov (United States)

Sindbis viral vectors target and inhibit the growth of various solid tumors in mouse models. However, their efficacy against blood cancer has not been well established. Here, we show that Sindbis vectors infect and efficiently trigger apoptosis in mouse BW5147 malignant hematopoietic T-cells, but only at low levels in human lymphoma and leukemia cells (Jurkat, Karpas, CEM, DHL and JB). The Mr 37/67?kD laminin receptor (LAMR) has been suggested to be the receptor for Sindbis virus. However, JB cells, which are infected by Sindbis at low efficiency, express high levels of LAMR, revealing that additional factors are involved in Sindbis tropism. To test the infectivity and therapeutic efficacy of Sindbis vectors against malignant hematopoietic cells in vivo, we injected BW5147 cells intraperitoneally into (C3HXAKR) F1 hybrid mice. We found that Sindbis vectors targeted the tumors and significantly prolonged survival of tumor-bearing mice. We also tested the Sindbis vectors in a transgenic CD4-Rgr model, which spontaneously develop thymic lymphomas. However, infectivity in this model was less efficient. Taken together, these results demonstrate that Sindbis vectors have the potential to target and kill hematopoietic malignancies in mice, but further research is needed to evaluate the mechanism underlining the susceptibility of human lymphoid malignancies to Sindbis therapy. PMID:22956041

Suzme, R; Tseng, J-C; Levin, B; Ibrahim, S; Meruelo, D; Pellicer, A

2012-11-01

274

VectorBase: A Data Resource for Invertebrate Vector Genomics  

OpenAIRE

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

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

2009-01-01

275

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

OpenAIRE

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

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

2013-01-01

276

Bluetongue vector species of Culicoides in Switzerland.  

Science.gov (United States)

Switzerland is historically recognized by the Office Internationale des Epizooties as free from bluetongue disease (BT) because of its latitude and climate. With bluetongue virus (BTV) moving north from the Mediterranean, an entomological survey was conducted in Switzerland in 2003 to assess the potential of the BTV vectors present. A total of 39 cattle farms located in three geographical regions, the Ticino region, the Western region and the region of the Grisons, were monitored during the vector season. Farms were located in areas at high risk of vector introduction and establishment based on the following characteristics: annual average temperature > 12.5 degrees C, average annual humidity >or= 60%, cattle farm. Onderstepoort black light traps were operated at the cattle farms generally for one night in July and one night in September. A total of 56 collections of Culicoides (Diptera: Ceratopogonidae) were identified morphologically. Only one single individual of Culicoides (Avaritia) imicola, the major Old World vector of BTV, was found in July 2003 in the Ticino region, one of the southernmost regions of Switzerland. In the absence of further specimens of C. imicola from Switzerland it is suggested that this individual may be a vagrant transported by wind from regions to the south of the country where populations of this species are known to occur. Alternative potential BTV vectors of the Culicoides (Culicoides) pulicaris and Culicoides (Avaritia) obsoletus complexes were abundant in all sampled regions with individual catches exceeding 70 000 midges per trap night. PMID:16874919

Cagienard, A; Griot, C; Mellor, P S; Denison, E; Stärk, K D C

2006-06-01

277

Interactions of vector solitons.  

Science.gov (United States)

In this paper, we study the interaction of two widely separated vector solitons in the nonintegrable coupled nonlinear Schrödinger (NLS) equations. Using a modification of Karpman-Solov'ev perturbation method, we derive dynamical equations for the evolution of both solitons' internal parameters. We show that these dynamical equations allow fixed points that correspond to stationary two-vector-soliton bound states if these solitons have the same phase in one component (same sign) and pi-phase difference in the other component (opposite sign). However, linear stability analysis indicates that these bound states are always unstable due to a phase-related unstable eigenvalue. We also investigate vector-soliton interactions and show that, in contrast to soliton interactions in the single NLS equation, vector solitons repel or attract each other depending not only on their relative phases but also on their initial position separation. Lastly, interaction of an arbitrary number of vector solitons is also studied in brief. All our analytical results are supported by direct numerical simulations. PMID:11497730

Yang, J

2001-08-01

278

Isotropy theorem for cosmological vector fields  

OpenAIRE

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 a...

Cembranos, J. A. R.; Hallabrin, C.; Maroto, A. L.; Jaren?o, S. J. Nu?n?ez

2012-01-01

279

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

280

Unit Vector Games  

OpenAIRE

McLennan and Tourky (2010) showed that "imitation games" provide a new view of the computation of Nash equilibria of bimatrix games with the Lemke-Howson algorithm. In an imitation game, the payoff matrix of one of the players is the identity matrix. We study the more general "unit vector games", which are already known, where the payoff matrix of one player is composed of unit vectors. Our main application is a simplification of the construction by Savani and von Stengel (2...

Savani, Rahul; Von Stengel, Bernhard

2015-01-01

281

Matrix vector analysis  

CERN Document Server

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

Eisenman, Richard L

2013-01-01

282

Sums and Gaussian vectors  

CERN Document Server

Surveys the methods currently applied to study sums of infinite-dimensional independent random vectors in situations where their distributions resemble Gaussian laws. Covers probabilities of large deviations, Chebyshev-type inequalities for seminorms of sums, a method of constructing Edgeworth-type expansions, estimates of characteristic functions for random vectors obtained by smooth mappings of infinite-dimensional sums to Euclidean spaces. A self-contained exposition of the modern research apparatus around CLT, the book is accessible to new graduate students, and can be a useful reference for researchers and teachers of the subject.

Yurinsky, Vadim Vladimirovich

1995-01-01

283

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.)

284

Bunyavirus-vector interactions.  

Science.gov (United States)

The Bunyaviridae family is comprised of more than 350 viruses, of which many within the Hantavirus, Orthobunyavirus, Nairovirus, Tospovirus, and Phlebovirus genera are significant human or agricultural pathogens. The viruses within the Orthobunyavirus, Nairovirus, and Phlebovirus genera are transmitted by hematophagous arthropods, such as mosquitoes, midges, flies, and ticks, and their associated arthropods not only serve as vectors but also as virus reservoirs in many cases. This review presents an overview of several important emerging or re-emerging bunyaviruses and describes what is known about bunyavirus-vector interactions based on epidemiological, ultrastructural, and genetic studies of members of this virus family. PMID:25402172

Horne, Kate McElroy; Vanlandingham, Dana L

2014-11-01

285

Bunyavirus-Vector Interactions  

Directory of Open Access Journals (Sweden)

Full Text Available The Bunyaviridae family is comprised of more than 350 viruses, of which many within the Hantavirus, Orthobunyavirus, Nairovirus, Tospovirus, and Phlebovirus genera are significant human or agricultural pathogens. The viruses within the Orthobunyavirus, Nairovirus, and Phlebovirus genera are transmitted by hematophagous arthropods, such as mosquitoes, midges, flies, and ticks, and their associated arthropods not only serve as vectors but also as virus reservoirs in many cases. This review presents an overview of several important emerging or re-emerging bunyaviruses and describes what is known about bunyavirus-vector interactions based on epidemiological, ultrastructural, and genetic studies of members of this virus family.

Kate McElroy Horne

2014-11-01

286

BRST quantization of vector and axial-vector gauge theory  

International Nuclear Information System (INIS)

The vector and axial-vector gauge theory is quantized in the geometrical BRST formalism. By applying the so-called horizontality condition, the BRST and anti-BRST transformation rules under the vector and axial-vector gauge transformations are obtained. At the same time, a quantum Lagrangian which is BRST and anti-BRST invariant is obtained. We discuss how the vector--axial-vector gauge theory [UV(N)xUA(N)] is related to the ''right''- and ''left''-handed gauge theory [UR(N)xUL(N)

287

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

288

The mass spectra of the old neutral vector mesons  

International Nuclear Information System (INIS)

Dirac's equation with a harmonic potential is used to obtain the mass spectro of the neutral vector mesons rho sup(o), ?, phi and K sup(o*). Predictions are in fairly good agreement with the experimental results

289

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

290

Supernormal Vector Configurations  

CERN Document Server

A configuration of lattice vectors is supernormal if it contains a Hilbert basis for every cone spanned by a subset. We study such configurations from various perspectives, including triangulations, integer programming and Groebner bases. Our main result is a bijection between virtual chambers of the configuration and virtual initial ideals of the associated binomial ideal.

Hosten, S; Sturmfels, B; Hosten, Serkan; Maclagan, Diane; Sturmfels, Bernd

2001-01-01

291

Singular Vectors' Subtle Secrets  

Science.gov (United States)

Social scientists use adjacency tables to discover influence networks within and among groups. Building on work by Moler and Morrison, we use ordered pairs from the components of the first and second singular vectors of adjacency matrices as tools to distinguish these groups and to identify particularly strong or weak individuals.

James, David; Lachance, Michael; Remski, Joan

2011-01-01

292

Elusive vector glueball  

International Nuclear Information System (INIS)

If the vector glueball ? exists in the mass range that theory suggests, its resonant production cross section can be detected in e+e- annihilation only if the decay width is very narrow ((le) a few MeV). Otherwise ? will be observed only indirectly through its mixing with ?(prime). We propose a few tests of the ?-?(prime) mixing for future charm factories

293

Modified montmorillonite as vector for gene delivery.  

Science.gov (United States)

Currently, gene delivery systems can be divided into two parts: viral or non-viral vectors. In general, viral vectors have a higher efficiency on gene delivery. However, they may sometimes provoke mutagenesis and carcinogenesis once re-activating in human body. Lots of non-viral vectors have been developed that tried to solve the problems happened on viral vectors. Unfortunately, most of non-viral vectors showed relatively lower transfection rate. The aim of this study is to develop a non-viral vector for gene delivery system. Montmorillonite (MMT) is one of clay minerals that consist of hydrated aluminum with Si-O tetrahedrons on the bottom of the layer and Al-O(OH)2 octahedrons on the top. The inter-layer space is about 12 A. The room is not enough to accommodate DNA for gene delivery. In the study, the cationic hexadecyltrimethylammonium (HDTMA) will be intercalated into the interlayer of MMT as a layer expander to expand the layer space for DNA accommodation. The optimal condition for the preparation of DNA-HDTMA-MMT is as follows: 1 mg of 1.5CEC HDTMA-MMT was prepared under pH value of 10.7 and with soaking time for 2 h. The DNA molecules can be protected from nuclease degradation, which can be proven by the electrophoresis analysis. DNA was successfully transfected into the nucleus of human dermal fibroblast and expressed enhanced green fluorescent protein (EGFP) gene with green fluorescence emission. The HDTMA-MMT has a great potential as a vector for gene delivery in the future. PMID:16488006

Lin, Feng-Huei; Chen, Chia-Hao; Cheng, Winston T K; Kuo, Tzang-Fu

2006-06-01

294

Random vector variational inequalities and random noncooperative vector equilibrium  

Directory of Open Access Journals (Sweden)

Full Text Available In this paper, we prove some existence theorems for random vector variational inequalities and an existence theorem for the random noncooperative vector equilibrium under suitable assumptions.

Gue Myung Lee

1997-01-01

295

Gravitational waves in vector inflation  

International Nuclear Information System (INIS)

We discuss the gravitational waves (GW) in the context of vector inflation. We derive the action for tensor perturbations and find that tachyonic instabilities are present in most (but not all) of the inflationary models with large fields. In contrast, the stability of the small field inflation (A?A? << 1/N) is ensured by the usual slow-roll conditions, where N is the total number of fields. For example, the Coleman–Weinberg potential and the power-law inflation are always stable in the small fields limit with an approximately flat spectrum of GW. We also provide some examples which lead to a rapid decay of GW and predict the absence of tensor modes in the CMB

296

Probabilistic classification vector machines.  

Science.gov (United States)

In this paper, a sparse learning algorithm, probabilistic classification vector machines (PCVMs), is proposed. We analyze relevance vector machines (RVMs) for classification problems and observe that adopting the same prior for different classes may lead to unstable solutions. In order to tackle this problem, a signed and truncated Gaussian prior is adopted over every weight in PCVMs, where the sign of prior is determined by the class label, i.e., +1 or -1. The truncated Gaussian prior not only restricts the sign of weights but also leads to a sparse estimation of weight vectors, and thus controls the complexity of the model. In PCVMs, the kernel parameters can be optimized simultaneously within the training algorithm. The performance of PCVMs is extensively evaluated on four synthetic data sets and 13 benchmark data sets using three performance metrics, error rate (ERR), area under the curve of receiver operating characteristic (AUC), and root mean squared error (RMSE). We compare PCVMs with soft-margin support vector machines (SVM(Soft)), hard-margin support vector machines (SVM(Hard)), SVM with the kernel parameters optimized by PCVMs (SVM(PCVM)), relevance vector machines (RVMs), and some other baseline classifiers. Through five replications of twofold cross-validation F test, i.e., 5 x 2 cross-validation F test, over single data sets and Friedman test with the corresponding post-hoc test to compare these algorithms over multiple data sets, we notice that PCVMs outperform other algorithms, including SVM(Soft), SVM(Hard), RVM, and SVM(PCVM), on most of the data sets under the three metrics, especially under AUC. Our results also reveal that the performance of SVM(PCVM) is slightly better than SVM(Soft), implying that the parameter optimization algorithm in PCVMs is better than cross validation in terms of performance and computational complexity. In this paper, we also discuss the superiority of PCVMs' formulation using maximum a posteriori (MAP) analysis and margin analysis, which explain the empirical success of PCVMs. PMID:19398403

Chen, Huanhuan; Tino, Peter; Yao, Xin

2009-06-01

297

[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

298

Generalized forms and vector fields  

Energy Technology Data Exchange (ETDEWEB)

The generalized vector is defined on an n-dimensional manifold. The interior product and Lie derivative acting on generalized p-forms, -1 {<=} p {<=} n are introduced. The generalized commutator of two generalized vectors is defined. Adding a correction term to Cartan's formula, the generalized Lie derivative's action on a generalized vector field is defined. We explore various identities of the generalized Lie derivative with respect to generalized vector fields, and discuss an application.

Chatterjee, Saikat; Lahiri, Amitabha; Guha, Partha [S N Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Calcutta 700 098 (India)

2006-12-15

299

Generalized forms and vector fields  

International Nuclear Information System (INIS)

The generalized vector is defined on an n-dimensional manifold. The interior product and Lie derivative acting on generalized p-forms, -1 ? p ? n are introduced. The generalized commutator of two generalized vectors is defined. Adding a correction term to Cartan's formula, the generalized Lie derivative's action on a generalized vector field is defined. We explore various identities of the generalized Lie derivative with respect to generalized vector fields, and discuss an application

300

Generalized forms and vector fields  

CERN Document Server

The generalized vector is defined on an $n$ dimensional manifold. Interior product, Lie derivative acting on generalized $p$-forms, $-1\\le p\\le n$ are introduced. Generalized commutator of two generalized vectors are defined. Adding a correction term to Cartan's formula the generalized Lie derivative's action on a generalized vector field is defined. We explore various identities of the generalized Lie derivative with respect to generalized vector fields, and discuss an application.

Chatterjee, S; Guha, P; Chatterjee, Saikat; Lahiri, Amitabha; Guha, Partha

2006-01-01

301

Generalized forms and vector fields  

OpenAIRE

The generalized vector is defined on an $n$ dimensional manifold. Interior product, Lie derivative acting on generalized $p$-forms, $-1\\le p\\le n$ are introduced. Generalized commutator of two generalized vectors are defined. Adding a correction term to Cartan's formula the generalized Lie derivative's action on a generalized vector field is defined. We explore various identities of the generalized Lie derivative with respect to generalized vector fields, and discuss an appl...

Chatterjee, Saikat; Lahiri, Amitabha; Guha, Partha

2006-01-01

302

On matrix variate Dirichlet vectors  

OpenAIRE

A matrix variate Dirichlet vector is a random vector of independent Wishart matrices 'divided' by their sum. Many properties of Dirichlet vectors are usually established through integral computations assuming existence of density for the Wishart's. We propose a method to deal with the general case where densities need not exist. On the other hand, in dimension larger than 2, Dirichlet processes reduce to Dirichlet vectors and posterior of Dirichlet need not be Dirichlet.

Bobecka, Konstencia; Emilion, Richard; Wesolowski, Jacek

2009-01-01

303

Multi Matrix Vector Coherent States  

OpenAIRE

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

304

Greedy vector quantization  

OpenAIRE

We investigate the greedy version of the $L^p$-optimal vector quantization problem for an $\\mathbb{R}^d$-valued random vector $X\\!\\in L^p$. We show the existence of a sequence $(a_N)_{N\\ge 1}$ such that $a_N$ minimizes $a\\mapsto\\big \\|\\min_{1\\le i\\le N-1}|X-a_i|\\wedge |X-a|\\big\\|_{L^p}$ ($L^p$-mean quantization error at level $N$ induced by $(a_1,\\ldots,a_{N-1},a)$). We show that this sequence produces $L^p$-rate optimal $N$-tuples $a^{(N)}=(a_1,\\ldots,a_{_N})$ ($i.e.$ the $...

Luschgy, Harald; Page?s, Gilles

2014-01-01

305

Exclusive vector meson production  

International Nuclear Information System (INIS)

The production of ground state vector mesons (V = ?, ?, ?, J/?, Y) has been extensively studied at ep collider. Latest results were obtained from the study of two pion exclusive electroproduction in the mass range 0.4 ??-1 of integrated luminosity collected during 1998 - 2000 on ep collider with center-of-mass energy 318 GeV. The analysis was carried out in the kinematic range of 2 2 2, 32 2. The two-pion invariant mass distribution is interpreted in terms of the pion electromagnetic form factor, |F(M??)|, assuming that the studied mass range includes the contributions of the ?, ?' and ?' vector meson states. The masses and widths of resonances are obtained and subsequently the Q2 dependence of the cross-section ratios ?(?'???)/?(?) and ?(????)/?(?) was extracted. The pion form factor obtained in the present analysis is compared to that obtained in e+e- ? ?+?-

306

Interframe Hierarchical Vector Quantization  

Science.gov (United States)

An interframe hierarchical vector quantizer (IHVQ) is presented that is capable of encoding image sequence scenes at rates below 0.3 bit per pixel per frame. A regular decomposition quadtree method is used to segment the interframe differential signal into homogeneous regions of different block size. Small blocks representing high contrast moving boundaries (i.e., the impulsive component of the difference signal) are vector quantized, whereas large blocks typically representing smooth regions of the image are encoded by the local sample mean of the region. The IHVQ system has a signal-to-noise ratio (SNR) at least 2 dB higher than the SNR of the interframe mean-reconstructed quadtree coding system.

Nasrabadi, Nasser M.; Lin, Shihkuan E.; Feng, Yushu

1989-07-01

307

Cosmological evolution in vector-tensor theories of gravity  

International Nuclear Information System (INIS)

We present a detailed study of the cosmological evolution in general vector-tensor theories of gravity without potential terms. We consider the evolution of the vector field throughout the expansion history of the Universe and carry out a classification of models according to the behavior of the vector field in each cosmological epoch. We also analyze the case in which the Universe is dominated by the vector field, performing a complete analysis of the system phase map and identifying those attracting solutions which give rise to accelerated expansion. Moreover, we consider the evolution in a universe filled with a pressureless fluid in addition to the vector field and study the existence of attractors in which we can have a transition from matter domination to vector domination with accelerated expansion so that the vector field may play the role of dark energy. We find that the existence of solutions with late-time accelerated expansion is a generic prediction of vector-tensor theories and that such solutions typically lead to the presence of future singularities. Finally, limits from local gravity tests are used to get constraints on the value of the vector field at small (Solar System) scales.

308

Engineering influenza viral vectors  

OpenAIRE

The influenza virus is a respiratory pathogen with a negative-sense, segmented RNA genome. Construction of recombinant influenza viruses in the laboratory was reported starting in the 1980s. Within a short period of time, pioneer researchers had devised methods that made it possible to construct influenza viral vectors from cDNA plasmid systems. Herein, we discuss the evolution of influenza virus reverse genetics, from helper virus-dependent systems, to helper virus-independent 17-plasmid sys...

Li, Junwei; Are?valo, Maria T.; Zeng, Mingtao

2013-01-01

309

Elusive vector glueball  

Energy Technology Data Exchange (ETDEWEB)

If the vector glueball {Omicron} exists in the mass range that theory suggests, its resonant production cross section can be detected in e{sup +}e{sup -} annihilation only if the decay width is very narrow ({le} a few MeV). Otherwise {Omicron} will be observed only indirectly through its mixing with {psi}{prime}. We propose a few tests of the {Omicron}-{psi}{prime} mixing for future charm factories.

Suzuki, Mahiko

2002-05-01

310

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

311

Supersymmetric vector particles  

International Nuclear Information System (INIS)

It is shown that a relativistic generalization of Witten's supersymmetric quantum mechanics yields the Proca field equations describing a spin one particle, and, in the massless case, the Maxwell equations and the Lorentz gauge condition. The generalization is based on a representation of the pseudoclassical complex Grassmann variables by rectangular rather than quadratic matrices at the quantum level and on a non-associative operator product. We study all possible supersymmetric couplings to external fields. These include scalar, vector and tensor fields. The couplings exhibit a quadrupole characteristics of the pseudoclassical particle. In particular the coupling to an external vector field may be formulated in a purely geometrical manner and interpreted as that of a pure electric quadrupole to the Maxwell field. The corresponding Schroedinger equation does therefore not obey the minimal coupling prescription. The tensor field may represent not only a Riemannian, but also a complex hermitian metric. In the Riemannian case the quantization prescription entails the well-known covariant generalization of the classical vector field equations. We also derive a classical limit of the quantum theory that involves only real numbers. Finally we speculate on the existance of na analogous non-standard quantization for extended supersymmetric field theories. (Author)

312

Current Knowledge of Leishmania Vectors in Mexico: How Geographic Distributions of Species Relate to Transmission Areas  

OpenAIRE

Leishmaniases are a group of vector-borne diseases with different clinical manifestations caused by parasites transmitted by sand fly vectors. In Mexico, the sand fly Lutzomyia olmeca olmeca is the only vector proven to transmit the parasite Leishmania mexicana to humans, which causes leishmaniasis. Other vector species with potential medical importance have been obtained, but their geographic distributions and relation to transmission areas have never been assessed. We modeled the ecological...

Gonza?lez, Camila; Rebollar-te?llez, Eduardo A.; Iba?n?ez-bernal, Sergio; Becker-fauser, Ingeborg; Marti?nez-meyer, Enrique; Peterson, A. Townsend; Sa?nchez-cordero, Vi?ctor

2011-01-01

313

Vector representation of tourmaline compositions  

Science.gov (United States)

The vector method for representing mineral compositions of amphibole and mica groups is applied to the tourmaline group. Consideration is given to the methods for drawing the relevant vector diagrams, relating the exchange vectors to one another, and contouring the diagrams for constant values of Na, Ca, Li, Fe, Mg, Al, Si, and OH. The method is used to depict a wide range of possible tourmaline end-member compositions and solid solutions, starting from a single point. In addition to vector depictions of multicomponent natural tourmalines, vectors are presented for simpler systems such as (Na,Al)-tourmalines, alkali-free tourmalines, and elbaites.

Burt, Donald M.

1989-01-01

314

Experimental infection of Hawai'i 'Amakihi (hemignathus virens) with West Nile virus and competence of a co-occurring vector, culex quinquefasciatus: potential impacts on endemic Hawaiian avifauna.  

Science.gov (United States)

Introduced mosquito-borne avian disease is a major limiting factor in the recovery and restoration of native Hawaiian forest birds. Annual epizootics of avian pox (Avipoxvirus) and avian malaria (Plasmodium relictum) likely led to the extinction of some species and continue to impact populations of susceptible Hawaiian honeycreepers (Drepanidinae). The introduction of a novel pathogen, such as West Nile virus (WNV), could result in further population declines and extinctions. During September and October 2004, we infected Hawai'i' Amakihi (Hemignathus virens) with a North American isolate of WNV by needle inoculation and mosquito bite to observe susceptibility, mortality, and illness in this endemic passerine, and to determine the vector competence of the co-occurring, introduced mosquito Culex quinquefasciatus. All experimentally infected Hawai'i ;Amakihi became viremic, with a mean titer >10(5) plaque-forming units (PFU)/ml, and they experienced clinical signs ranging from anorexia and lethargy to ataxia. The fatality rate among needle-inoculated Hawai'i' Amakihi (n=16) was 31.3%, but mortality in free-ranging birds is likely to increase due to predation, starvation, thermal stress, and concomitant infections of avian malaria and pox. Surviving Hawai'i' Amakihi seem to clear WNV from the peripheral blood by 7-10 days postinfection (DPI), and neutralizing antibodies were detected from 9 to 46 DPI. In transmission trials, Hawaiian Cx. quinquefasciatus proved to be a competent vector and Hawai'i Amakihi an adequate amplification host of WNV, suggesting that epizootic WNV could readily become an additional limiting factor of some native Hawaiian bird populations.

Lapointe, D.A.; Hofmeister, E.K.; Atkinson, C.T.; Porter, R.E.; Dusek, R.J.

2009-01-01

315

HSV Recombinant Vectors for Gene Therapy  

OpenAIRE

The very deep knowledge acquired on the genetics and molecular biology of herpes simplex virus (HSV), has allowed the development of potential replication-competent and replication-defective vectors for several applications in human healthcare. These include delivery and expression of human genes to cells of the nervous systems, selective destruction of cancer cells, prophylaxis against infection with HSV or other infectious diseases, and targeted infection to specific tissues or organs. Repl...

Manservigi, Roberto; Argnani, Rafaela; Marconi, Peggy

2010-01-01

316

Cosmological implications of Bumblebee vector models  

CERN Document Server

The Bumblebee Model of spontaneous Lorentz symmetry breaking is explored in a cosmological context, considering a single non-zero time component for the vector field. The relevant dynamic equations for the evolution of the Universe are derived and its properties and physical significance studied. We conclude that a late-time de Sitter expansion of the Universe can be replicated, and attempt to constrain the parameter of the potential driving the spontaneous symmetry breaking.

Capelo, Diogo

2015-01-01

317

Generation of stable vector-producing cells for retroviral vectors.  

Science.gov (United States)

INTRODUCTIONThis procedure describes the generation of clonal vector-producing cells that will provide an unlimited amount of unrearranged retroviral vector. The procedure involves transfection of one packaging cell line to generate a vector that is used to transduce a second packaging cell line. The resultant vector-producing clones generally contain a single integrated copy of the retroviral vector, and virus produced from this integrated vector is as genetically homogeneous as possible. Although the vector produced by a given packaging cell line can sometimes be used to transduce the same cell line, the transduction rate is typically low because of receptor blockage by the Env protein made by the target packaging cells. Indeed, this procedure will select for target cells that express low Env protein levels and thus are less resistant to transduction, but at the same time will ultimately produce less vector because of low Env production. Therefore, to obtain the highest vector titers, it is important to use pairs of packaging cells such that receptor blockage is not an issue. In this example, we use PE501 ecotropic packaging cells for transfection and broad-host-range PT67 packaging cells to make stable vector-producing cells. PMID:21356804

Cornetta, Kenneth; Pollok, Karen E; Miller, A Dusty

2008-01-01

318

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

319

Warm vector inflation  

Energy Technology Data Exchange (ETDEWEB)

In this Letter we introduce the “warm vector inflation” scenario. In warm inflation scenario radiation is produced during the inflation epoch and reheating is avoided. Slow-roll and perturbation parameters of this model are presented. We develop our model using intermediate inflation model. In this case, the model is compatible with observational data. We also study the model using another exact cosmological solution, named logamediate scenario. We present slow-roll and Hubble parameters, power spectrum and tensor–scalar ratio in terms of inflaton. The model is compatible with WMAP7 and Planck observational data.

Setare, M.R., E-mail: rezakord@ipm.ir; Kamali, V., E-mail: vkamali1362@gmail.com

2013-10-07

320

Vectoring: Steering a Plane  

Science.gov (United States)

In this two part activity, learners work in pairs or individually to discover how vectoring the thrust from a jet engine affects movement of an airplane. In part one, learners construct an F-15 ACTIVE model with a balloon engine. In part two, learners conduct a series of experiments by changing the angle of the straw to control the direction of the thrust. This activity emphasizes the scientific method including prediction, observation, data collection, and analysis. This lesson plan includes background information, an extension and a sample worksheet.

NASA

2011-08-20

321

On Killing vectors and harmonic vectors at quantization of gravitation  

International Nuclear Information System (INIS)

Attention is paid to two shortcomings occuring at quantization in the curved spacetime: mathematical shortcoming consisting in the killing vector absence in arbitrary Riemann space and physical one consisting in absence of energy-momentum tensor of the gravitational field. It is shown, that both shortcomings may be removed, if the killing vectors are replaced by harmonic vectors corresponding to shift generators of the Poincare group existing in arbitrary Riemann space

322

Risk based surveillance for vector borne diseases  

DEFF Research Database (Denmark)

Increased temperatures and changes in rainfall pattern are likely to facilitate the spread and establishment of new vector borne diseases in the Baltic See Region. There are a large number of potential vector borne threats to the area. Existing endemic vector borne diseases are likely to increase and new exotic diseases like Usutu and West Nile Virus may lead to outbreaks in the region. In the worst case the combined effect of climate change and globalization may potentially lead to European outbreaks of important zoonotic mosquito borne infections like Rift Valley Fever in cattle and Japanese Encephalitis in swine. Being able to model the impact of climate and environmental change on the transmission intensity of vector borne diseases is potentially a powerful tool to both monitor and prevent outbreaks in a cost effective way. The recent unexpected outbreaks of bluetongue and Schmallenberg virus in ruminants have been attributed an increase in European temperatures. Mathematical models clearly demonstratethe potential for increased virus transmission at elevated temperatures. however there is little evidence to support the idea that the spread of these tropical viruses in northern Europe is the direct result of climate change. The potential for virus transmission by biting midges was here modeled monthly for the Baltic See Region and the rest of Europe. The results showed that Baltic See Region has a lower transmission potential than most other areas in Europe. And the model identified an increasing trend in transmission potential over the last 25 years. However the model suggested that the climate in the Baltic See Region has always permitted transmission of these diseases. The model therefore suggests that a presently unknown factor until recently prevented introduction and spread in Northern Europe. This model approach may be used as a basis for risk based surveillance. In risk based surveillance limited resources for surveillance are targeted at geographical areas most at risk and only when the risk is high. This makes risk based surveillance a cost effective alternative to the present surveillance strategies based on random samples. We still don’t understand the mechanisms underlying the recent outbreaks of bluetongue, Schmallenberg, Usutu virus, tick borne encephalitis or dirofilarial worms in the Baltic See Region. It is therefore not possible to use mathematical models to pinpoint the next outbreak of an exotic vector borne disease. A new outbreak will most likely be detected by a veterinarian deciding to submit a sample based on a subjective clinical suspicion. But the question is how far the epidemic will progress before a veterinarian decides to submit this crucial sample to a diagnostic laboratory. Risk based surveillance models may reduce this delay. An important feature of risk based surveillance models is their ability to continuously communicate the level of risk to veterinarians and hence increase awareness when risk is high. This is essential for submission of samples and hence early detection of outbreaks. Models for vector borne diseases in Denmark have demonstrated dramatic variation in outbreak risk during the season and between years. The Danish VetMap project aims to make these risk based surveillance estimates available on the veterinarians smart phones, thus allowing easy access to risk estimates when in the field. Knowing when and where the potential risk for transmission of a specific vector borne disease is high is likely to help veterinarians decide when and when not to submit a sample to a diagnostic laboratory. This may both increase sensitivity of national surveillance and reduce the cost.

BØdker, Rene

323

Nonlinear birefringence in plasmas: Polarization dynamics, vector modulational instability, and vector solitons  

Energy Technology Data Exchange (ETDEWEB)

The propagation of an elliptically polarized intense laser pulse in an unmagnetized collisionless uniform plasma is considered. A multiple scale perturbation theory is employed to show that in a weakly relativistic regime, evolution of the components of vector potential is governed by two coherently coupled nonlinear Schrödinger (NLS) equations. A set of equations describing the evolution of Stokes parameters is derived within the continuous wave approximation and the dynamics of components of field amplitude is studied. The polarization dynamics of a pulse is investigated by means of numerical solution of the coupled NLS equations. A detailed analysis of vector modulational instability is presented and the possibility for occurrence of various kinds of vector solitary waves is addressed.

Borhanian, Jafar, E-mail: borhanian@uma.ac.ir [Department of Physics, Faculty of Science, University of Mohaghegh Ardabili, P. O. Box 179, Ardabil (Iran, Islamic Republic of)

2014-06-15

324

Engineering Biomaterial Systems to Enhance Viral Vector Gene Delivery  

Science.gov (United States)

Integrating viral gene delivery with engineered biomaterials is a promising strategy to overcome a number of challenges associated with virus-mediated gene delivery, including inefficient delivery to specific cell types, limited tropism, spread of vectors to distant sites, and immune responses. Viral vectors can be combined with biomaterials either through encapsulation within the material or immobilization onto a material surface. Subsequent biomaterial-based delivery can increase the vector's residence time within the target site, thereby potentially providing localized delivery, enhancing transduction, and extending the duration of gene expression. Alternatively, physical or chemical modification of viral vectors with biomaterials can be employed to modulate the tropism of viruses or reduce inflammatory and immune responses, both of which may benefit transduction. This review describes strategies to promote viral gene delivery technologies using biomaterials, potentially providing opportunities for numerous applications of gene therapy to inherited or acquired disorders, infectious disease, and regenerative medicine. PMID:21629221

Jang, Jae-Hyung; Schaffer, David V; Shea, Lonnie D

2011-01-01

325

Distributed support vector machines.  

Science.gov (United States)

A truly distributed (as opposed to parallelized) support vector machine (SVM) algorithm is presented. Training data are assumed to come from the same distribution and are locally stored in a number of different locations with processing capabilities (nodes). In several examples, it has been found that a reasonably small amount of information is interchanged among nodes to obtain an SVM solution, which is better than that obtained when classifiers are trained only with the local data and comparable (although a little bit worse) to that of the centralized approach (obtained when all the training data are available at the same place). We propose and analyze two distributed schemes: a "naïve" distributed chunking approach, where raw data (support vectors) are communicated, and the more elaborated distributed semiparametric SVM, which aims at further reducing the total amount of information passed between nodes while providing a privacy-preserving mechanism for information sharing. We show the feasibility of our proposal by evaluating the performance of the algorithms in benchmarks with both synthetic and real-world datasets. PMID:16856672

Navia-Vázquez, A; Gutiérrez-González, D; Parrado-Hernández, E; Navarro-Abellán, J J

2006-07-01

326

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

327

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

328

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

329

Flexibility in cell targeting by pseudotyping lentiviral vectors.  

Science.gov (United States)

Lentiviral vectors have become an important research tool and have just entered into clinical trials. As wild-type lentiviruses engage specific receptors that have limited tropism, most investigators have replaced the endogenous envelope glycoprotein with an alternative envelope. Such pseudotyped vectors have the potential to infect a wide variety of cell types and species. Alternatively, selection of certain viral envelope glycoproteins may also facilitate cell targeting to enhance directed gene transfer. We describe the method for generating pseudotyped vector and provide information regarding available pseudotypes and their respective target tissues. PMID:20225035

Bischof, Daniela; Cornetta, Kenneth

2010-01-01

330

Vector Field Models of Inflation and Dark Energy  

OpenAIRE

We consider several new classes of viable vector field alternatives to the inflaton and quintessence scalar fields. Spatial vector fields are shown to be compatible with the cosmological anisotropy bounds if only slightly displaced from the potential minimum while dominant, or if driving an anisotropic expansion with nearly vanishing quadropole today. The Bianchi I model with a spatial field and an isotropic fluid is studied as a dynamical system, and several types of scalin...

Koivisto, Tomi S.; Mota, David F.

2008-01-01

331

Effective Vector Data Transmission and Visualization Using HTML5  

OpenAIRE

In this paper we evaluate the potential of the next major revision of HTML (Hypertext Markup Language), that is HTML5, to provide an effective platform for the transmission and visualization of vector based geographical data. Relative to the current version of HTML, HTML 4.01, HTML5 offers an improved platform to perform these tasks through greater interoperability with existing technologies and the introduction of many new API’s. Visualization of vector data can be achieved ...

Corcoran, Padraig; Mooney, Peter; Winstanley, Adam; Bertolotto, Michela

2011-01-01

332

Transfer Entropy on Rank Vectors  

OpenAIRE

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

333

Quantization of Equivariant Vector Bundles  

OpenAIRE

The quantization of vector bundles is defined. Examples are constructed for the well controlled case of equivariant vector bundles over compact coadjoint orbits. (Coadjoint orbits are symplectic spaces with a transitive, semisimple symmetry group.) In preparation for the main result, the quantization of coadjoint orbits is discussed in detail. This subject should not be confused with the quantization of the total space of a vector bundle such as the cotangent bundle.

Hawkins, Eli

1997-01-01

334

Average Competitive Learning Vector Quantization  

OpenAIRE

We propose a new algorithm for vector quantization:Average Competitive Learning Vector Quantization(ACLVQ). It is a rather simple modi cation of the classical Competitive Learning Vector Quantization(CLVQ). This new formulation gives us similar results for the quantization error to those obtained by the CLVQ and reduce considerably the computation time to achieve the optimal quantizer. We establish the convergence of the method via the Kushner-Clark approach, and compare the two algorithms vi...

Salomon, Luis Armando; Fort, Jean-claude; Lozada Chang, Li-vang

2012-01-01

335

VLSI Processor For Vector Quantization  

Science.gov (United States)

Pixel intensities in each kernel compared simultaneously with all code vectors. Prototype high-performance, low-power, very-large-scale integrated (VLSI) circuit designed to perform compression of image data by vector-quantization method. Contains relatively simple analog computational cells operating on direct or buffered outputs of photodetectors grouped into blocks in imaging array, yielding vector-quantization code word for each such block in sequence. Scheme exploits parallel-processing nature of vector-quantization architecture, with consequent increase in speed.

Tawel, Raoul

1995-01-01

336

Innate immune responses to AAV vectors  

Directory of Open Access Journals (Sweden)

Full Text Available Gene replacement therapy by in vivo delivery of adeno-associated virus (AAV is attractive as a potential treatment for a variety of genetic disorders. However, while AAV has been used successfully in many models, other experiments in clinical trials and in animal models have been hampered by undesired responses from the immune system. Recent studies of AAV immunology have focused on the elimination of transgene-expressing cells by the adaptive immune system, yet the innate immune system also has a critical role, both in the initial response to the vector and in prompting a deleterious adaptive immune response. Responses to AAV vectors are primarily mediated by the TLR9 MyD88 pathway, which induces the production of proinflammatory cytokines by activating the NF ?B pathways and inducing type I IFN production; self-complementary AAV vectors enhance these inflammatory processes. Additionally, the alternative NF ?B pathway influences transgene expression in cells transduced by AAV. This review highlights these recent discoveries regarding innate immune responses to AAV and discusses strategies to ablate these potentially detrimental signaling pathways.

ArunSrivastava

2011-09-01

337

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

338

Estimation of vector velocity  

DEFF Research Database (Denmark)

Using a pulsed ultrasound field, the two-dimensional velocity vector can be determined with the invention. The method uses a transversally modulated ultrasound field for probing the moving medium under investigation. A modified autocorrelation approach is used in the velocity estimation. The new estimator automatically compensates for the axial velocity, when determining the transverse velocity by using fourth order moments rather than second order moments. The estimation is optimized by using a lag different from one in the estimation process, and noise artifacts are reduced by using averaging of RF samples. Further, compensation for the axial velocity can be introduced, and the velocity estimation is done at a fixed depth in tissue to reduce spatial velocity dispersion.

Jensen, JØrgen Arendt Technical University of Denmark,

339

Chameleon vector bosons  

International Nuclear Information System (INIS)

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 constrain any B-L force much stronger than gravity with range longer than 0.1 ?m, there remains an experimental window for a long-range chameleonic B-L force. Such a force could be much stronger than gravity, and long or infinite range in vacuum, but have an effective range near the surface of the earth which is less than a micron.

340

Vector-Tensor and Vector-Vector Decay Amplitude Analysis of B0->phi K*0  

CERN Document Server

We perform an amplitude analysis of the decays B0->phi K^*_2(1430)0, phi K^*(892)0, and phi(K pi)^0_S-wave with a sample of about 384 million BBbar pairs recorded with the BABAR detector. The fractions of longitudinal polarization f_L of the vector-tensor and vector-vector decay modes are measured to be 0.853 +0.061-0.069 +-0.036 and 0.506 +-0.040 +-0.015, respectively. Overall, twelve parameters are measured for the vector-vector decay and seven parameters for the vector-tensor decay, including the branching fractions and parameters sensitive to CP-violation.

Aubert, B; Abrams, G S; Adye, T; Ahmed, S; Alam, M S; Albert, J; Aleksan, R; Allen, M T; Allison, J; Altenburg, D D; Andreotti, M; Angelini, C; Anulli, F; Arnaud, N; Asgeirsson, D J; Aston, D; Azzolini, V; Baak, M A; Back, J J; Baldini-Ferroli, R; Band, H R; Banerjee, Sw; Bard, D J; Barlow, N R; Barlow, R J; Barrett, M; Bartoldus, R; Batignani, G; Battaglia, M; Bauer, J M; Bechtle, P; Beck, T W; Behera, P K; Bellini, F; Benayoun, M; Benelli, G; Berger, N; Bernard, D; Berryhill, J W; Best, D S; Bettarini, S; Bettoni, D; Bevan, A J; Bhimji, W; Bhuyan, B; Bianchi, F; Biasini, M; Biesiada, J; Blanc, F; Blaylock, G; Blinov, V E; Bloom, P C; Blount, N L; Bomben, M; Bondioli, M; Bonneaud, G R; Bosisio, L; Boutigny, D; Bowerman, D A; Boyd, J T; Bozzi, C; Brandenburg, G; Brandt, T; Brau, J E; Briand, H; Brown, C M; Brown, D N; Bruinsma, M; Brunet, S; Bucci, F; Buchanan, C; Bugg, W; Bukin, A D; Bula, R; Burchat, P R; Burke, J P; Button-Shafer, J; Buzzo, A; Bóna, M; Cahn, R N; Calabrese, R; Calcaterra, A; Calderini, G; Campagnari, C; Carpinelli, M; Cartaro, C; Cavallo, N; Cavoto, G; Cenci, R; Chai, X; Chaisanguanthum, K S; Chao, M; Charles, E; Charles, M J; Chauveau, J; Chavez, C A; Chen, A; Chen, C; Chen, E; Chen, J C; Chen, S; Chen, X; Chen, X R; Cheng, B; Cheng, C H; Chia, Y M; Cibinetto, G; Clark, P J; Clarke, C K; Claus, R; Cochran, J; Coleman, J P; Contri, R; Convery, M R; Corwin, L A; Cossutti, F; Cottingham, W N; Couderc, F; Covarelli, R; Cowan, G; Cowan, R; Crawley, H B; Cremaldi, L; Cunha, A; Curry, S; Côté, D; D'Orazio, A; Dahmes, B; Dallapiccola, C; Danielson, N; Dasu, S; Datta, M; Dauncey, P D; David, P; Davier, M; Davis, C L; De Nardo, Gallieno; De Sangro, R; Del Amo-Sánchez, P; Del Buono, L; Del Re, D; Della Ricca, G; Denig, A G; Di Lodovico, F; Di Marco, E; Dingfelder, J C; Dittongo, S; Dong, L; Dorfan, J; Druzhinin, V P; Dubitzky, R S; Dubois-Felsmann, G P; Dujmic, D; Dunwoodie, W M; Dvoretskii, A; Ebert, M; Eckhart, E A; Eckmann, R; Edgar, C L; Edwards, A J; Egede, U; Eigen, G; Eisner, A M; Elmer, P; Emery, S; Ernst, J A; Eschenburg, V; Eschrich, I; Eyges, V; Fabozzi, F; Faccini, R; Fang, F; Feltresi, E; Ferrarotto, F; Ferroni, F; Field, R C; Finocchiaro, G; Flacco, C J; Flack, R L; Flächer, H U; Flood, K T; Ford, K E; Ford, W T; Forster, I J; Forti, F; Fortin, D; Foulkes, S D; Franek, B; Frey, R; Fritsch, M; Fry, J R; Fulsom, B G; Gabathuler, E; Gaidot, A; Gallo, F; Gamba, D; Gamet, R; Gan, K K; Ganzhur, S F; Gao, Y; Gary, J W; Gaspero, M; Gatto, C; Gaz, A; George, K A; Gill, M S; Giorgi, M A; Gladney, L; Glanzman, T; Godang, R; Golubev, V B; Gowdy, S J; Gradl, W; Graham, M T; Graugès-Pous, E; Grenier, P; Gritsan, A V; Grosdidier, G; Groysman, Y; Guo, Z J; Hadavand, H K; Haire, M; Halyo, V; Hamano, K; Hamel de Monchenault, G; Hamon, O; Harrison, P F; Harrison, T J; Hart, A J; Hartfiel, B L; Hast, C; Hauke, A; Hawkes, C M; Hearty, C; Held, T; Hertzbach, S S; Heusch, C A; Hill, E J; Hirschauer, J F; Hitlin, D G; Hollar, J J; Hong, T M; Honscheid, K; Hopkins, D A; Hrynóva, T; Hufnagel, D; Hulsbergen, W D; Hutchcroft, D E; Höcker, A; Igonkina, O; Innes, W R; Izen, J M; Jackson, P D; Jackson, P S; Jacobsen, R G; Jain, V; Jasper, H; Jawahery, A; Jessop, C P; Judd, D; Kadyk, J A; Kagan, H; Karyotakis, Yu; Kass, R; Kelsey, M H; Kerth, L T; Khan, A; Kim, H; Kim, P; Kirkby, D; Klose, V; Knecht, N S; Koch, H; Kolb, J A; Kolomensky, Yu G; Kovalskyi, D; Kowalewski, R V; Kozanecki, Witold; Kreisel, A; Krishnamurthy, M; Kroeger, R; Kroseberg, J; Kukartsev, G; Kutter, P E; Kyberd, P; La Vaissière, C de; Lacker, H M; Lae, C K; Lafferty, G D; Lanceri, L; Lange, D J; Lankford, A J; Latham, T E; Latour, E; Lau, Y P; Lazzaro, A; Le Diberder, F R; Lee, C L; Lees, J P; Legendre, M; Leith, D W G S; Lepeltier, V; Leruste, P; Lewandowski, B; Li Gioi, L; Li, S; Li, X; Lista, L; Liu, H; Lo Vetere, M; LoSecco, J M; Lockman, W S; Lombardo, V; Long, O; Lopes-Pegna, D; Lopez-March, N; Lou, X C; Lu, M; Luitz, S; Lund, P; Luppi, E; Lusiani, A; Lutz, A M; Lynch, G; Lynch, H L; Lü, C; Lüth, V; MacFarlane, D B; Macri, M M; Mader, W F; Majewski, S A; Malcles, J; Mallik, U; Mancinelli, G; Mandelkern, M A; Marchiori, G; Margoni, M; Marks, J; Marsiske, H; Martínez-Vidal, F; Mattison, T S; Mazur, M A; Mazzoni, M A; McKenna, J A; McMahon, T R; Mclachlin, S E; Meadows, B T; Mellado, B; Menges, W; Merkel, J; Messner, R; Meyer, N T; Meyer, W T; Mihályi, A; Mir, L M; Mishra, K; Mohanty, G B; Monge, M R; Monorchio, D; Moore, T B; Morandin, M; Morganti, M; Morganti, S; Morii, M; Muheim, F; Müller, D R; Nagel, M; Naisbit, M T; Narsky, I; Nash, J A; Nauenberg, U; Neal, H; Negrini, M; Neri, N; Nesom, G; Nicholson, H; Nikolich, M B; Nogowski, R; Nugent, I M; O'Grady, C P; Ocariz, J; Ofte, I; Olaiya, E O; Olivas, A; Olsen, J; Onuchin, A P; Orimoto, T J; Oyanguren, A; Ozcan, V E; Paar, H P; Pacetti, S; Palano, A

2007-01-01

341

Exploring vector meson masses in nuclear collisions  

CERN Document Server

The formalism developed earlier by us for the propagation of a resonance in the nuclear medium in proton-nucleus collisions has been modified to the case of vector boson production in heavy-ion collisions. The first part of the talk describes this formalism. The formalism includes coherently the contribution to the observed di-lepton production from the decay of a vector boson inside as well as outside the nuclear medium. The calculated invariant rho mass distributions are presented for the $\\rho $-meson production using optical potentials estimated within the VDM and the resonance model. In the second part of the talk we write a formalism for coherent rho production in proton nucleus collisions and explore the sensitivity of the (p,p$^\\prime \\rho ^0$) reaction cross section to medium mass modification of the rho meson.

Jain, B K; Kundu, B; Das, Swapan; Kundu, Bijoy

2000-01-01

342

Thrust vector control using electric actuation  

Science.gov (United States)

Presently, gimbaling of launch vehicle engines for thrust vector control is generally accomplished using a hydraulic system. In the case of the space shuttle solid rocket boosters and main engines, these systems are powered by hydrazine auxiliary power units. Use of electromechanical actuators would provide significant advantages in cost and maintenance. However, present energy source technologies such as batteries are heavy to the point of causing significant weight penalties. Utilizing capacitor technology developed by the Auburn University Space Power Institute in collaboration with the Auburn CCDS, Marshall Space Flight Center (MSFC) and Auburn are developing EMA system components with emphasis on high discharge rate energy sources compatible with space shuttle type thrust vector control requirements. Testing has been done at MSFC as part of EMA system tests with loads up to 66000 newtons for pulse times of several seconds. Results show such an approach to be feasible providing a potential for reduced weight and operations costs for new launch vehicles.

Bechtel, Robert T.; Hall, David K.

1995-01-01

343

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

344

On shelling and flag vectors  

OpenAIRE

This note defines a flag vector for $i$-graphs. The construction applies to any finite combinatorial object that can be shelled. Two possible connections to quantum topology are mentioned. Further details appear in the author's "On quantum topology, hypergraphs and flag vectors", (preprint q-alg/9708001).

Fine, Jonathan

1997-01-01

345

Geometric Quantization of Vector Bundles  

OpenAIRE

I repeat my definition for quantization of a vector bundle. For the case of Toeplitz and geometric quantization of a compact Kaehler Manifold, I give a construction for quantizing any smooth vector bundle which depends functorially on a choice of connection on the bundle.

Hawkins, Eli

1998-01-01

346

Order statistics learning vector quantizer  

OpenAIRE

We propose a novel class of learning vector quantizers (LVQs) based on multivariate data ordering principles. A special case of the novel LVQ class is the median LVQ, which uses either the marginal median or the vector median as a multivariate estimator of location. The performance of the proposed marginal median LVQ in color image quantization is demonstrated by experiments

Pitas, I.; Kotropoulos, C.; Nikolaidis, N.; Yang, R.; Gabbouj, M.

2010-01-01

347

Cosmological perturbations from vector inflation  

International Nuclear Information System (INIS)

We analyze the behavior of linear perturbations in vector inflation. In contrast to scalar field inflation, the linearized theory with vector fields contains couplings between scalar, vector, and tensor modes. The perturbations decouple only in the ultraviolet limit, which allows us to carry out the canonical quantization. Superhorizon perturbations can be approximately analyzed due to suppressed mixing between different modes in the small field models. We find that the vector perturbations of the metric decay exponentially, but the scalar and tensor modes could remain weakly coupled throughout the evolution. As a result, vector inflation can produce significant correlations of the scalar and tensor modes in the CMB. For realistic models the effect is rather small, but not negligible.

348

Divergence-based vector quantization.  

Science.gov (United States)

Supervised and unsupervised vector quantization methods for classification and clustering traditionally use dissimilarities, frequently taken as Euclidean distances. In this article, we investigate the applicability of divergences instead, focusing on online learning. We deduce the mathematical fundamentals for its utilization in gradient-based online vector quantization algorithms. It bears on the generalized derivatives of the divergences known as Fréchet derivatives in functional analysis, which reduces in finite-dimensional problems to partial derivatives in a natural way. We demonstrate the application of this methodology for widely applied supervised and unsupervised online vector quantization schemes, including self-organizing maps, neural gas, and learning vector quantization. Additionally, principles for hyperparameter optimization and relevance learning for parameterized divergences in the case of supervised vector quantization are given to achieve improved classification accuracy. PMID:21299418

Villmann, Thomas; Haase, Sven

2011-05-01

349

State Vectors and Physical States  

CERN Document Server

Causality and the relativity of simultaneity seem at odds with the apparently sudden, acausal state-vector changes ("collapses") characteristic of quantum phenomena. The problem of how physical phenomena can be causally determined, have the probabilities predicted by quantum theory, and be consistent with special relativity appears to be solved by the assumption, essentially the same as one first used by Aharonov, Bergmann, and Lebowitz to address a different problem, that the "initial" and "final" state vectors of a phenomenon or observation, along with certain other state vectors, all represent the system's state at all times. Each member of such an aggregate of state vectors is postulated to represent a different aspect of a physical state rather than a state, so that most of the state vectors in effect constitute a set of nonlocal hidden variables. Various implications of this assumption are illustrated through several physical situations. Among the results is a somewhat surprising resolution of a paradox...

Watson, W N

2000-01-01

350

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

351

Dirac equation exact solutions for generalized asymmetrical Hartmann potentials  

CERN Document Server

In this work we solve the Dirac equation by constructing the exact bound state solutions for a mixing of vector and scalar generalized Hartmann potentials. This is done provided the vector potential is equal to or minus the scalar potential. The cases of some quasi-exactly solvable and Morse-like potentials are briefly commented.

Dutra, Alvaro de Souza

2007-01-01

352

Light Flavor Vector and Pseudo Vector Mesons from a Light-Cone QCD Inspired Effective Hamiltonian Model with SU(3) Flavor Mixing Interactions  

International Nuclear Information System (INIS)

Based on the light-cone effective Hamiltonian with confining potential and SU(3) flavor mixing interactions, the flavor mixing mesons on the u, d, and s quark sectors are investigated. The mass eigen equations of the flavor mixing vector and pseudo vector mesons are solved. The calculated masses are in good agreement with the experimental data. (the physics of elementary particles and fields)

353

Vector fields in multidimensional cosmology  

International Nuclear Information System (INIS)

Vector fields in the expanding Universe are considered within the multidimensional theory of general relativity. Vector fields in general relativity form a three-parametric variety. Our consideration includes the fields with a nonzero covariant divergence. Depending on the relations between the particular parameters and the symmetry of a problem, the vector fields can be longitudinal and/or transverse, ultrarelativistic (i.e. massless) or nonrelativistic (massive), and so on. The longitudinal and transverse vector fields are considered separately in detail in the background of the de Sitter cosmological metric. In most cases the field equations reduce to Bessel equations, and their temporal evolution is analyzed analytically. The energy-momentum tensor of the most simple zero-mass longitudinal vector fields enters the Einstein equations as an additive to the cosmological constant. In this case the de Sitter metric is the exact solution of the Einstein equations. Hence, the most simple zero-mass longitudinal vector field pretends to be an adequate tool for macroscopic description of dark energy as a source of the expansion of the Universe at a constant rate. The zero-mass vector field does not vanish in the process of expansion. On the contrary, massive fields vanish with time. Though their amplitude is falling down, the massive fields make the expansion accelerated.

354

Pattern vectors from algebraic graph theory.  

Science.gov (United States)

Graph structures have proven computationally cumbersome for pattern analysis. The reason for this is that, before graphs can be converted to pattern vectors, correspondences must be established between the nodes of structures which are potentially of different size. To overcome this problem, in this paper, we turn to the spectral decomposition of the Laplacian matrix. We show how the elements of the spectral matrix for the Laplacian can be used to construct symmetric polynomials that are permutation invariants. The coefficients of these polynomials can be used as graph features which can be encoded in a vectorial manner. We extend this representation to graphs in which there are unary attributes on the nodes and binary attributes on the edges by using the spectral decomposition of a Hermitian property matrix that can be viewed as a complex analogue of the Laplacian. To embed the graphs in a pattern space, we explore whether the vectors of invariants can be embedded in a low-dimensional space using a number of alternative strategies, including principal components analysis (PCA), multidimensional scaling (MDS), and locality preserving projection (LPP). Experimentally, we demonstrate that the embeddings result in well-defined graph clusters. Our experiments with the spectral representation involve both synthetic and real-world data. The experiments with synthetic data demonstrate that the distances between spectral feature vectors can be used to discriminate between graphs on the basis of their structure. The real-world experiments show that the method can be used to locate clusters of graphs. PMID:16013758

Wilson, Richard C; Hancock, Edwin R; Luo, Bin

2005-07-01

355

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

356

Structural Learning of Attack Vectors for Generating Mutated XSS Attacks  

Directory of Open Access Journals (Sweden)

Full Text Available Web applications suffer from cross-site scripting (XSS attacks that resulting from incomplete or incorrect input sanitization. Learning the structure of attack vectors could enrich the variety of manifestations in generated XSS attacks. In this study, we focus on generating more threatening XSS attacks for the state-of-the-art detection approaches that can find potential XSS vulnerabilities in Web applications, and propose a mechanism for structural learning of attack vectors with the aim of generating mutated XSS attacks in a fully automatic way. Mutated XSS attack generation depends on the analysis of attack vectors and the structural learning mechanism. For the kernel of the learning mechanism, we use a Hidden Markov model (HMM as the structure of the attack vector model to capture the implicit manner of the attack vector, and this manner is benefited from the syntax meanings that are labeled by the proposed tokenizing mechanism. Bayes theorem is used to determine the number of hidden states in the model for generalizing the structure model. The paper has the contributions as following: (1 automatically learn the structure of attack vectors from practical data analysis to modeling a structure model of attack vectors, (2 mimic the manners and the elements of attack vectors to extend the ability of testing tool for identifying XSS vulnerabilities, (3 be helpful to verify the flaws of blacklist sanitization procedures of Web applications. We evaluated the proposed mechanism by Burp Intruder with a dataset collected from public XSS archives. The results show that mutated XSS attack generation can identify potential vulnerabilities.

Yi-Hsun Wang

2010-09-01

357

[Adenovirus vectors and their clinical application in gene therapy].  

Science.gov (United States)

The potential therapeutic application of the gene transfer technology with adenovirus vectors seems to be enormous. Adenovirus vectors offer several advantages over other vectors, but several important limitations of adenovirus mediated gene transfer are also known. Great number of studies in inherited diseases and in different cancer therapy clinical trials have provided information of critical importance for design of efficient clinical protocols. Clinical trials have been extended to the treatment of many other diseases, too. There are about thirty currently active gene therapy protocols for the treatment only of HIV-1 infection in the USA. These programs aim to confer protective immunity against HIV-1 transmission to individuals who are in risk of infection, to develop preventive or therapeutic vaccines for patients with AIDS and other infectious diseases. Gene therapy represents one of the most important developments in oncology, however, before this can be realised as standard treatment the technical problems of gene delivery and higher safety must be overcome. The early--first and second generation--adenovirus vectors are now likely to be phased out for most diseases, and further experiments seem to be necessary. It might be change to the third generation or other, more modern vector application in clinical trials, as the helper dependent vectors. Almost all transcriptional unit is removed from the DNA of these vectors ("gutless vectors"), therefore they cannot reproduce, give higher gene expression and far less inflammatory. Despite the latest achievement reported in vector design it is not possible to predict yet to what extent and when gene therapy will be effective. PMID:11697063

Adám, E; Nász, I

2001-09-23

358

Vector meson production at HERA  

OpenAIRE

We show that the lowest-order QCD calculation in a simple model of elastic vector-meson production does reproduce correctly the ratios of cross sections for rho, phi and J/psi, both in photoproduction and in high-Q2 quasi-elastic scattering. The dependence of the slopes on the mass of the vector meson is reproduced as well. We examine the lower-energy data, and find that the energy dependence of the cross section does not depend on Q2, but may depend on the vector-meson mass.

Cudell, J. R.; Royen, I.

2008-01-01

359

Vector calculation of particle code  

International Nuclear Information System (INIS)

The development of vector computer requires the modification of the algorithm into a suitable form for vector calculation. Among many algorithms, the particle code is a typical example which has suffered a damage in the calculation on supercomputer owing to its possibility of recurrent data access in collecting cell-wise quantities from particle's quartities. In this article, we report a new method to liberate the particle code from recurrent calculations. It should be noticed, however, that the method may depend on the architecture of supercomputer, and works well on FACOM VP-100 and VP-200: the indirect data accessing must be vectorized and its speed should be fast. (Mori, K.)

360

Vectors of rickettsiae in Africa.  

Science.gov (United States)

Vector-borne diseases are caused by parasites, bacteria, or viruses transmitted by the bites of hematophagous arthropods. In Africa, there has been a recent emergence of new diseases and the re-emergence of existing diseases, usually with changes in disease epidemiology (e.g., geographical distribution, prevalence, and pathogenicity). In Africa, rickettsioses are recognized as important emerging vector-borne infections in humans. Rickettsial diseases are transmitted by different types of arthropods, ticks, fleas, lice, and mites. This review will examine the roles of these different arthropod vectors and their geographical distributions. PMID:23168053

Bitam, Idir

2012-12-01

361

Vector control of induction machines  

CERN Document Server

After a brief introduction to the main law of physics and fundamental concepts inherent in electromechanical conversion, ""Vector Control of Induction Machines"" introduces the standard mathematical models for induction machines - whichever rotor technology is used - as well as several squirrel-cage induction machine vector-control strategies. The use of causal ordering graphs allows systematization of the design stage, as well as standardization of the structure of control devices. ""Vector Control of Induction Machines"" suggests a unique approach aimed at reducing parameter sensitivity for

Robyns, Benoit

2012-01-01

362

Vector meson and axial-vector diquark decay constants  

International Nuclear Information System (INIS)

A natural generalization to the case of unequal constituent masses of the formula which gives the correct decay constants for vector mesons of the quarkonium type is proposed. Within the philosophy where diquarks are used as baryonic constituents, this allows us to evaluate the decay widths for all vector particles both mesons and diquarks to be used later on the calculate the baryon lifetimes. (Author)

363

Adjuvants and vector systems for allergy vaccines.  

Science.gov (United States)

Allergen-specific immunotherapy represents a curative treatment of type I allergies. Subcutaneous immunotherapy is conducted with allergens adsorbed on aluminum hydroxide or calcium phosphate particles, whereas sublingual immunotherapy relies on high doses of soluble allergen without any immunopotentiator. There is a potential benefit of adjuvants enhancing regulatory and Th1 CD4+T cell responses during specific immunotherapy. Molecules affecting dendritic cells favor the induction of T regulatory cell and Th1 responses and represent valid candidate adjuvants for allergy vaccines. Furthermore, the interest in viruslike particles and mucoadhesive particulate vector systems, which may better address the allergen(s) to tolerogenic antigen-presenting cells, is documented. PMID:21530828

Moingeon, Philippe; Lombardi, Vincent; Saint-Lu, Nathalie; Tourdot, Sophie; Bodo, Véronique; Mascarell, Laurent

2011-05-01

364

Vector independent transmission of the vector-borne bluetongue virus.  

Science.gov (United States)

Abstract Bluetongue is an economically important disease of ruminants. The causative agent, Bluetongue virus (BTV), is mainly transmitted by insect vectors. This review focuses on vector-free BTV transmission, and its epizootic and economic consequences. Vector-free transmission can either be vertical, from dam to fetus, or horizontal via direct contract. For several BTV-serotypes, vertical (transplacental) transmission has been described, resulting in severe congenital malformations. Transplacental transmission had been mainly associated with live vaccine strains. Yet, the European BTV-8 strain demonstrated a high incidence of transplacental transmission in natural circumstances. The relevance of transplacental transmission for the epizootiology is considered limited, especially in enzootic areas. However, transplacental transmission can have a substantial economic impact due to the loss of progeny. Inactivated vaccines have demonstrated to prevent transplacental transmission. Vector-free horizontal transmission has also been demonstrated. Since direct horizontal transmission requires close contact of animals, it is considered only relevant for within-farm spreading of BTV. The genetic determinants which enable vector-free transmission are present in virus strains circulating in the field. More research into the genetic changes which enable vector-free transmission is essential to better evaluate the risks associated with outbreaks of new BTV serotypes and to design more appropriate control measures. PMID:24645633

van der Sluijs, Mirjam Tineke Willemijn; de Smit, Abraham J; Moormann, Rob J M

2014-03-19

365

Modification to the Capsid of the Adenovirus Vector That Enhances Dendritic Cell Infection and Transgene-Specific Cellular Immune Responses  

OpenAIRE

Adenovirus (Ad) gene transfer vectors can be used to transfer and express antigens and function as strong adjuvants and thus are useful platforms for the development of genetic vaccines. Based on the hypothesis that Ad vectors with enhanced infectibility of dendritic cells (DC) may be able to evoke enhanced immune responses against antigens encoded by the vector in vivo, the present study analyzes the vaccine potential of an Ad vector expressing ?-galactosidase as a model antigen and genetic...

Worgall, Stefan; Busch, Annette; Rivara, Michael; Bonnyay, David; Leopold, Philip L.; Merritt, Robert; Hackett, Neil R.; Rovelink, Peter W.; Bruder, Joseph T.; Wickham, Thomas J.; Kovesdi, Imi; Crystal, Ronald G.

2004-01-01

366

Application of Chimeric Feline Foamy Virus-Based Retroviral Vectors for the Induction of Antiviral Immunity in Cats †  

OpenAIRE

In order to define the potential and applicability of replication-competent foamy virus-based vaccine vectors, recombinant feline foamy virus (FFV) vectors encoding defined segments of the feline calicivirus (FCV) capsid protein E domain were constructed. In cell cultures, these FFV-FCV vectors efficiently transduced and expressed a hybrid fusion protein consisting of the essential FFV Bet protein and the attached FCV E domains. The stability of the vectors in vitro was inversely correlated t...

Schwantes, Astrid; Truyen, Uwe; Weikel, Joachim; Weiss, Christian; Lo?chelt, Martin

2003-01-01

367

Scalable production of adenovirus vectors.  

Science.gov (United States)

Recombinant adenoviruses (AdV) are highly efficient at gene transfer for a broad spectrum of cell types and species. They became one of the vectors of choice for gene delivery and expression of foreign proteins in gene therapy and vaccination purposes. To meet the need of significant amounts of adenoviral vectors for preclinical and possibly clinical uses, scalable and reproducible production processes are required.In this chapter, we review processes used for scalable production of two types of first generation (E1-deleted) adenoviral vectors (Human and Canine) using stirred tank bioreactors. The production of adenovirus vectors using either suspension (HEK 293) or anchorage-dependent cells (MDCK-E1) are described to exemplify scalable production processes with different cell-culture types. The downstream processes will be covered in the next chapter. PMID:24132486

Silva, Ana Carina; Fernandes, Paulo; Sousa, Marcos F Q; Alves, Paula M

2014-01-01

368

Kinematics Problem: Acceleration with Vectors  

Science.gov (United States)

Physicists use arrows to represent many things in diagrams (position is in meters and time is in seconds). The learner is to identify the vector quantity that is being represented by the arrow in the simulation.

Christian, Wolfgang; Belloni, Mario

2006-01-20

369

Fast Multilevel Support Vector Machines  

OpenAIRE

Solving different types of optimization models (including parameters fitting) for support vector machines on large-scale training data is often an expensive computational task. This paper proposes a multilevel algorithmic framework that scales efficiently to very large data sets. Instead of solving the whole training set in one optimization process, the support vectors are obtained and gradually refined at multiple levels of coarseness of the data. The proposed framework inc...

Razzaghi, Talayeh; Safro, Ilya

2014-01-01

370

Singular vectors under random perturbation  

OpenAIRE

Computing the first few singular vectors of a large matrix is a problem that frequently comes up in statistics and numerical analysis. Given the presence of noise, exact calculation is hard to achieve, and the following problem is of importance: \\vskip2mm \\centerline {\\it How much a small perturbation to the matrix changes the singular vectors ?} \\vskip2mm Answering this question, classical theorems, such as those of Davis-Kahan and Wedin, give tight estimates for the w...

Van Vu

2010-01-01

371

Vectors And The Quarterback Pass  

Science.gov (United States)

The following resource is a NFL sponsored, National Science Foundation funded program intended to teach students about scientific concepts by using the popular sport of Football. Each lesson is accompanied by an informative and fast paced video. In this activity, students will watch as NBC's Lester Holt looks at the role vectors play every time an NFL quarterback throws a pass. Then they will be shown how to use vectors to calculate the speed and direction needed for a completed pass.

2010-01-01

372

Vector triplets at the LHC  

Directory of Open Access Journals (Sweden)

Full Text Available Several popular extensions of the Standard Model predict extra vector fields that transform as triplets under the gauge group SU(2L. 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.

Pérez-Victoria Manuel

2013-11-01

373

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

Directory of Open Access Journals (Sweden)

Full Text Available 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.

Martin Löchelt

2013-07-01

374

Shifting suitability for malaria vectors across Africa with warming climates  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Climates are changing rapidly, producing warm climate conditions globally not previously observed in modern history. Malaria is of great concern as a cause of human mortality and morbidity, particularly across Africa, thanks in large part to the presence there of a particularly competent suite of mosquito vector species. Methods I derive spatially explicit estimates of human populations living in regions newly suitable climatically for populations of two key Anopheles gambiae vector complex species in Africa over the coming 50 years, based on ecological niche model projections over two global climate models, two scenarios of climate change, and detailed spatial summaries of human population distributions. Results For both species, under all scenarios, given the changing spatial distribution of appropriate conditions and the current population distribution, the models predict a reduction of 11.3–30.2% in the percentage of the overall population living in areas climatically suitable for these vector species in coming decades, but reductions and increases are focused in different regions: malaria vector suitability is likely to decrease in West Africa, but increase in eastern and southern Africa. Conclusion Climate change effects on African malaria vectors shift their distributional potential from west to east and south, which has implications for overall numbers of people exposed to these vector species. Although the total is reduced, malaria is likely to pose novel public health problems in areas where it has not previously been common.

Peterson A Townsend

2009-05-01

375

Vectorization of the KENO V.a criticality safety code  

International Nuclear Information System (INIS)

The development of the vector processor, which is used in the current generation of supercomputers and is beginning to be used in workstations, provides the potential for dramatic speed-up for codes that are able to process data as vectors. Unfortunately, the stochastic nature of Monte Carlo codes prevents the old scalar version of these codes from taking advantage of the vector processors. New Monte Carlo algorithms that process all the histories undergoing the same event as a batch are required. Recently, new vectorized Monte Carlo codes have been developed that show significant speed-ups when compared to the scalar version of themselves or equivalent codes. This paper discusses the vectorization of an already existing and widely used criticality safety code, KENO V.a All the changes made to KENO V.a are transparent to the user making it possible to upgrade from the standard scalar version of KENO V.a to the vectorized version without learning a new code

376

Singular vectors, predictability and ensemble forecasting for weather and climate  

International Nuclear Information System (INIS)

The local instabilities of a nonlinear dynamical system can be characterized by the leading singular vectors of its linearized operator. The leading singular vectors are perturbations with the greatest linear growth and are therefore key in assessing the system’s predictability. In this paper, the analysis of singular vectors for the predictability of weather and climate and ensemble forecasting is discussed. An overview of the role of singular vectors in informing about the error growth rate in numerical models of the atmosphere is given. This is followed by their use in the initialization of ensemble weather forecasts. Singular vectors for the ocean and coupled ocean–atmosphere system in order to understand the predictability of climate phenomena such as ENSO and meridional overturning circulation are reviewed and their potential use to initialize seasonal and decadal forecasts is considered. As stochastic parameterizations are being implemented, some speculations are made about the future of singular vectors for the predictability of weather and climate for theoretical applications and at the operational level. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Lyapunov analysis: from dynamical systems theory to applications’. (review)

377

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; Hegde, Anant

2005-01-01

378

Visualizing and Manipulating Automatic Document Orientation Methods Using Vector Fields  

OpenAIRE

We introduce and illustrate a design framework whereby tabletop documents are oriented according to vector fields that can be visualized and altered by end users. We explore and illustrate the design space using interactive 2D mockups and show how this approach can potentially combine the advantages of the fully manual and fully automatic document orientation methods previously proposed in the literature.

Dragicevic, Pierre; Shi, Yuanchun

2009-01-01

379

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

380

On The relation between fields and potentials in non-abelian gauge theories  

International Nuclear Information System (INIS)

It is shown that, to any element U(x) of the gauge group it corresponds to one parameter family of fields. Each member of the family can be derived from two different potentials not related by any gauge transformation, unless U(x) satisfies an integrability condition. The example given by T. T. Wu and C.N Yang, for three dimensions and the group SU2, characterized by the unit radial vector (n vector = r vector / r), is generalized to any arbitrary unit vector field n vector (r vector) (n vector. n vector =1)

381

Reconstruction of Vector-like Top Partner from Fully Hadronic Final States  

CERN Document Server

We investigate the potential to search for the vector-like top partner in fully hadronic final states at the LHC. An algorithm is developed which kinematically reconstructs the vector-like top. We show that for moderate masses and a large branching fraction into top quark and Higgs boson, the reconstruction works with good quality.

Endo, Motoi; Ishikawa, Kazuya; Stoll, Martin

2014-01-01

382

Elliptic-symmetry vector optical fields.  

Science.gov (United States)

We present in principle and demonstrate experimentally a new kind of vector fields: elliptic-symmetry vector optical fields. This is a significant development in vector fields, as this breaks the cylindrical symmetry and enriches the family of vector fields. Due to the presence of an additional degrees of freedom, which is the interval between the foci in the elliptic coordinate system, the elliptic-symmetry vector fields are more flexible than the cylindrical vector fields for controlling the spatial structure of polarization and for engineering the focusing fields. The elliptic-symmetry vector fields can find many specific applications from optical trapping to optical machining and so on. PMID:25321015

Pan, Yue; Li, Yongnan; Li, Si-Min; Ren, Zhi-Cheng; Kong, Ling-Jun; Tu, Chenghou; Wang, Hui-Tian

2014-08-11

383

Vector meson-vector meson interaction and dynamically generated resonances  

International Nuclear Information System (INIS)

We report upon 11 composite meson states, dynamically generated from the vector meson–vector meson interaction using the local hidden gauge formalism within a unitary approach. Six of these states are associated to the f0(1370), f0(1710), f2(1270), f'2(1525), a2(1320) and K*2(1430) resonances. At the same time we predict five other states with the quantum numbers of h1, a0, b1, K*0, and K1 which could be tested by future experiments.

384

Vector-valued automorphic forms and vector bundles  

CERN Document Server

For an arbitrary discrete group $\\Gamma$ and an $n$-dimensional complex representation $R$ of $\\Gamma$, we prove the existence of $n$ linearly independent vector-valued automorphic forms for $\\Gamma$ with multiplier $R$. To this end, we realize these automorphic forms as sections of a rank $n$ vector bundle attached to a 1-cocycle with coefficients in the sheaf $\\mbox{GL}(n,{\\mathcal O}_X)$, $X$ being the quotient of the Poincar\\'e half-plane by $\\Gamma$ completed with the cusps of $\\Gamma$.

Saber, Hicham

2013-01-01

385

Vector-valued automorphic forms and vector bundles  

OpenAIRE

For an arbitrary discrete group $\\Gamma$ and an $n$-dimensional complex representation $R$ of $\\Gamma$, we prove the existence of $n$ linearly independent vector-valued automorphic forms for $\\Gamma$ with multiplier $R$. To this end, we realize these automorphic forms as sections of a rank $n$ vector bundle attached to a 1-cocycle with coefficients in the sheaf $\\mbox{GL}(n,{\\mathcal O}_X)$, $X$ being the quotient of the Poincar\\'e half-plane by $\\Gamma$ completed with the c...

Saber, Hicham; Sebbar, Abdellah

2013-01-01

386

Vector description of nonlinear magnetization  

Science.gov (United States)

The definition of the nonlinear magnetization, which is usually applied in investigating superconductors is discussed in this paper. The nonlinear magnetization of the superconductor, as the response to the alternating magnetic field, is a periodic time function and is determined by the sequence of complex numbers ?n= ?n'+i ?n?, n=1,2,3,… . The sequence ? n is named harmonic susceptibility. Finding some limits in this definition we propose a new description, substituting the complex sequence ? n with the sequence of real covariant vectors limit??j n. Such a definition of the nonlinear magnetization, using the vectors limit??n, allows to determine function M( t) of an investigated system for an arbitrary initial phase ?o of the inducing magnetic field H ac=h ac sin(?t+? o) . Vector description, in our opinion, is superior to the complex one in respect of explicitness, simplicity, and universality. Circular diagrams are used to illustrate the new vector description. We also show how the vectors of the harmonic susceptibility can be derived from both numeric calculations and experimental data.

Rysak, A.; Korczak, S. Z.

2001-06-01

387

Neutral quark matter in a Nambu-Jona Lasinio model with vector interaction  

CERN Document Server

We investigate the three flavor Nambu-Jona Lasinio model of neutral quark matter at zero temperature and finite density, keeping into account the scalar, the pseudoscalar and the Kobayashi-Maskawa-'t Hooft interactions as well as the repulsive vector plus axial-vector interaction terms (vector extended NJL, VENJL in the following). We focus on the effect of the vector interaction on the chiral restoration at finite density in neutral matter. We also study the evolution of the charged pseudoscalar meson energies as a function of the quark chemical potential.

Abuki, H; Ruggieri, M

2009-01-01

388

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

389

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

390

Stochastic vector and tensor fields applied to strain modelling  

Energy Technology Data Exchange (ETDEWEB)

In this paper a brief introduction to the theory of stochastic vector and tensor fields is given. Necessary and sufficient conditions for isotropic vector random fields are reviewed and necessary conditions for second order tensors are developed. These models increase the flexibility of the usual geostatistical models but at the cost of increased complexity. This complexity can be reduced to a manageable level for a class of tensor fields that are associated with strain. The potential for modelling fractures using strain models is briefly discussed. (Author)

Daly, C. [Roxar Ltd., Wimbledon (United Kingdom)

2001-05-01

391

On Spinors and Null Vectors  

CERN Document Server

We investigate the relations between spinors and null vectors in Clifford algebra with particular emphasis on the conditions that a spinor must satisfy to be simple (also: pure). In particular we prove: i) a new property for null vectors: each of them bisects spinor space into two parts of equal size; ii) that simple spinors form one-dimensional subspaces of spinor space; iii) a necessary and sufficient condition for a spinor to be simple that generalizes a theorem of Cartan and Chevalley that appears now as a corollary of this result. We also show how to write down easily the most general spinor with a given associated totally null plane.

Budinich, Marco

2014-01-01

392

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

393

Topological vector spaces and distributions  

CERN Document Server

""The most readable introduction to the theory of vector spaces available in English and possibly any other language.""-J. L. B. Cooper, MathSciNet ReviewMathematically rigorous but user-friendly, this classic treatise discusses major modern contributions to the field of topological vector spaces. The self-contained treatment includes complete proofs for all necessary results from algebra and topology. Suitable for undergraduate mathematics majors with a background in advanced calculus, this volume will also assist professional mathematicians, physicists, and engineers.The precise exposition o

Horvath, John

2013-01-01

394

Prevalence and potential vectors of Haemoproteus in Nebraska mouring doves.  

Science.gov (United States)

Three hundred and nine mourning doves (Zenaida macroura) from Lancaster County, Nebraska, were examined for species of Haemoproteus. Older doves possessed higher Haemoproteus prevalences than younger doves. Mean total prevalence for each dove age group was as follows: adults, 61% H. sacharovi and 83% H. maccallumi; immatures, 35% H. sacharovi and 42% H. maccallumi; and nestlings, 31% H. sacharovi and 16% H. maccallumi. Yearly prevalences were less variable in mature doves than in immature and nestling doves. No correlation between nestling and parent Haemoproteus infections were observed, but nestmates in 10 or 18 nests harbored equivalent infections. Stilbometopa podopostyla and Microlynchia pusilla (Hippoboscidae) were collected from Nebraska doves. Hippoboscidae were collected from doves of all ages from April to August. Dove baited fly traps yielded Culex tarsalis and C. pipiens in Nebraska and Culicoides haematopotus, C. crepuscularis, and Simulium aureaum in Ames, Iowa. PMID:806709

Greiner, E C

1975-04-01

395

Adenoviral Vectors in Veterinary Vaccine Development: Potential for Further Development  

OpenAIRE

 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 th...

Ndi, Olasumbo L.; Barton, Mary D.; Thiru Vanniasinkam

2013-01-01

396

Potential leafhopper vectors associated with potatoes in Alaska  

Science.gov (United States)

Leafhopper transmitted phytoplasma diseases are an emerging problem for potato and vegetable producers in the conterminous United States of America (USA). Due to its geographical isolation and climatic constrains, Alaska is considered relatively free of diseases and insect pests. Potato growers in t...

397

Helper-dependent adenoviral vectors for liver-directed gene therapy.  

Science.gov (United States)

Helper-dependent adenoviral (HDAd) vectors devoid of all viral-coding sequences are promising non-integrating vectors for liver-directed gene therapy because they have a large cloning capacity, can efficiently transduce a wide variety of cell types from various species independent of the cell cycle and can result in long-term transgene expression without chronic toxicity. The main obstacle preventing clinical applications of HDAd for liver-directed gene therapy is the host innate inflammatory response against the vector capsid proteins that occurs shortly after intravascular vector administration resulting in acute toxicity, the severity of which is dependent on vector dose. Intense efforts have been focused on elucidating the factors involved in this acute response and various strategies have been investigated to improve the therapeutic index of HDAd vectors. These strategies have yielded encouraging results with the potential for clinical translation. PMID:21470977

Brunetti-Pierri, Nicola; Ng, Philip

2011-04-15

398

Improved adeno-associated virus (AAV) serotype 1 and 5 vectors for gene therapy  

Science.gov (United States)

Despite significant advancements with recombinant AAV2 or AAV8 vectors for liver directed gene therapy in humans, it is well-recognized that host and vector-related immune challenges need to be overcome for long-term gene transfer. To overcome these limitations, alternate AAV serotypes (1–10) are being rigorously evaluated. AAV5 is the most divergent (55% similarity vs. other serotypes) and like AAV1 vector is known to transduce liver efficiently. AAV1 and AAV5 vectors are also immunologically distinct by virtue of their low seroprevalence and minimal cross reactivity against pre-existing AAV2 neutralizing antibodies. Here, we demonstrate that targeted bio-engineering of these vectors, augment their gene expression in murine hepatocytes in vivo (up to 16-fold). These studies demonstrate the feasibility of the use of these novel AAV1 and AAV5 vectors for potential gene therapy of diseases like hemophilia. PMID:23665951

Sen, Dwaipayan; Balakrishnan, Balaji; Gabriel, Nishanth; Agrawal, Prachi; Roshini, Vaani; Samuel, Rekha; Srivastava, Alok; Jayandharan, Giridhara R.

2013-01-01

399

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

400

Shape of the constraint effective potential  

International Nuclear Information System (INIS)

Using results from chiral perturbation theory for O(N)-symmetric models in the spontaneously broken phase, we study the distribution of the mean field vector ?=V-1?ddx vector ?(x) at large volume. We show that this distribution obeys a scaling law and we calculate the shape of the constraint effective potential in the scaling limit. (orig.)

401

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

402

The Klein paradox and the mass spectra of the neutral vector mesons  

International Nuclear Information System (INIS)

We use Dirac's equation with a long range harmonic potential to obtain the mass spectra of the neutral vector mesons rho0, ?, PHI, Ksup(0*) and psi. Our predictions are in fairly good agreement with the experimental results. (author)

403

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 stereodynamics in future experiments and exact computations. Analytic results for the Ne-NO(A2?) 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' and k-j-k'-j' correlations in rotationally inelastic Ar-NO(X2?) 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.)

404

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

405

Alpharetroviral Vectors: From a Cancer-Causing Agent to a Useful Tool for Human Gene Therapy  

Directory of Open Access Journals (Sweden)

Full Text Available Gene therapy using integrating retroviral vectors has proven its effectiveness in several clinical trials for the treatment of inherited diseases and cancer. However, vector-mediated adverse events related to insertional mutagenesis were also observed, emphasizing the need for safer therapeutic vectors. Paradoxically, alpharetroviruses, originally discovered as cancer-causing agents, have a more random and potentially safer integration pattern compared to gammaretro- and lentiviruses. In this review, we provide a short overview of the history of alpharetroviruses and explain how they can be converted into state-of-the-art gene delivery tools with improved safety features. We discuss development of alpharetroviral vectors in compliance with regulatory requirements for clinical translation, and provide an outlook on possible future gene therapy applications. Taken together, this review is a broad overview of alpharetroviral vectors spanning the bridge from their parental virus discovery to their potential applicability in clinical settings.

Julia D. Suerth

2014-12-01

406

A note on transverse axial vector and vector anomalies in U(1) gauge theories  

International Nuclear Information System (INIS)

The transverse axial vector and vector anomalies in four-dimensional U(1) gauge theories studied in [Phys. Lett. B 507 (2001) 351] is reexamined by means of perturbative method. The absence of transverse anomalies for both axial vector and vector current is verified. We also show that the Pauli-Villars regularization and dimensional regularization gives the same result on the transverse anomaly of both axial vector and vector current

407

A Note on Transverse Axial Vector and Vector Anomalies in U(1) Gauge Theories  

OpenAIRE

The transverse axial vector and vector anomalies in four-dimensional U(1) gauge theories studied in [10] is reexamined by means of perturbative methods. The absence of transverse anomalies for both axial vector and vector current is verified. We also show that the Pauli-Villars regularization and dimensional regularization give the same result on the transverse anomaly of both axial vector and vector current.

Sun, Wei-min; Zong, Hong-shi; Chen, Xiang-song; Wang, Fan

2003-01-01

408

Hyperbranched polysiloxysilane nanoparticles for nonviral gene delivery vectors and nanoprobes  

Science.gov (United States)

We report an approach to produce predefined surface charge tunable gene delivery vectors using siloxysilsane-based polymer for gene delivery studies. To obtain nonviral vectors, new series of hyperbranched polysiloxysilane (HBPS) were synthesized, and the end groups in polymer structures have modified with hydrophilic molecules; in other words, carboxylic acid and quaternary ammonium groups were employed into terminal structures to give the amphiphilicity. The novelty of these amphiphilic HBPS polymers lies in the fact that nanoparticles with different zeta potential (surface charge density) can be easily tailored and functionalized. These polymeric nanoparticles which containing various chemical groups on the surface indicated altered surface charge distributions (from -40 to +64mV). Finally, the use of these nanoparticles as efficient gene delivery vectors was demonstrated by means of in vitro transfection study using ?- galactosidase plasmid and pEGFP-N1 plasmid, and the most efficient combination was obtained using HBPS-CN30:70.

Kim, Won Jin; Bonoiu, Adela C.; Lee, Kwang-Sup; Hayakawa, Teruaki; Xia, Cheng; Kakimoto, Masa-aki; Pudavar, Haridas E.; Prasad, Paras N.

2009-08-01

409

Diffractive photoproduction of vector mesons at the LHC  

CERN Document Server

We confront saturation-based results for diffractive $\\psi(2s)$ and $\\rho$ production at HERA and $J/\\psi$ photoproduction with all available data including recent ones from HERA, ALICE and LHCb, finding a good agreement. We show that the $t$-distribution of differential cross-section of photoproduction of vector mesons offers a unique opportunity to discriminate among saturation and non-saturation models. This is due to emergence of a pronounced dip (or multiple dips) in the $t$-distribution of diffractive photoproduction of vector mesons at relatively large, but potentially accessible $|t|$ that can be traced back to the unitarity features of colour dipole amplitude in the saturation regime. We provide various predictions for exclusive (photo)-production of different vector mesons including the ratio of $\\psi(2s)/J/\\psi$ at HERA, the LHC and at future colliders.

Armesto, Néstor

2014-01-01

410

Vector field electron tomography of magnetic materials: Theoretical development  

International Nuclear Information System (INIS)

The theory of vector field electron tomography, the reconstruction of the three-dimensional magnetic induction around a magnetized object, is derived within the framework of Lorentz transmission electron microscopy. The tomographic reconstruction method uses as input two orthogonal tilt series of magnetic phase maps and is based on the vector slice theorem. An analytical reconstruction of the magnetic induction of a single magnetic dipole is presented as a proof-of-concept. The method is compared to two previously reported approaches: a reconstruction starting from the gradient of the magnetic phase maps, and a direct reconstruction of the magnetic vector potential. Numerical examples as well as estimates of the reconstruction errors for a range of magnetic particle shapes are reported

411

Segregated and Synchronized Vector Solutions for Nonlinear Schrödinger Systems  

Science.gov (United States)

We consider the following nonlinear Schrödinger system in {{R}^3} \\{begin{array}{ll}-? u + P(|x|)u = ? u2u + ? v^2u,quad x in {R}^3,\\? v + Q(|x|)v = ? v2v + ? u^2v,quad x in {R}^3,. where P( r) and Q( r) are positive radial potentials, {? > 0, ? > 0} and {? in {R}} is a coupling constant. This type of system arises, in particular, in models in Bose-Einstein condensates theory. We examine the effect of nonlinear coupling on the solution structure. In the repulsive case, we construct an unbounded sequence of non-radial positive vector solutions of segregated type, and in the attractive case we construct an unbounded sequence of non-radial positive vector solutions of synchronized type. Depending upon the system being repulsive or attractive, our results exhibit distinct characteristic features of vector solutions.

Peng, Shuangjie; Wang, Zhi-qiang

2013-04-01

412

Potential theory of radiation  

Science.gov (United States)

A theoretical method is being developed by which the structure of a radiation field can be predicted by a radiation potential theory, similar to a classical potential theory. The introduction of a scalar potential is justified on the grounds that the spectral intensity vector is irrotational. The vector is also solenoidal in the limits of a radiation field in complete radiative equilibrium or in a vacuum. This method provides an exact, elliptic type equation that will upgrade the accuracy and the efficiency of the current CFD programs required for the prediction of radiation and flow fields. A number of interesting results emerge from the present study. First, a steady state radiation field exhibits an optically modulated inverse square law distribution character. Secondly, the unsteady radiation field is structured with two conjugate scalar potentials. Each is governed by a Klein-Gordon equation with a frictional force and a restoring force. This steady potential field structure and the propagation of radiation potentials are consistent with the well known results of classical electromagnetic theory. The extension of the radiation potential theory for spray combustion and hypersonic flow is also recommended.

Chiu, Huei-Huang

1989-01-01

413

RNA-based viral vectors.  

Science.gov (United States)

The advent of reverse genetic approaches to manipulate the genomes of both positive (+) and negative (-) sense RNA viruses allowed researchers to harness these genomes for basic research. Manipulation of positive sense RNA virus genomes occurred first largely because infectious RNA could be transcribed directly from cDNA versions of the RNA genomes. Manipulation of negative strand RNA virus genomes rapidly followed as more sophisticated approaches to provide RNA-dependent RNA polymerase complexes coupled with negative-strand RNA templates were developed. These advances have driven an explosion of RNA virus vaccine vector development. That is, development of approaches to exploit the basic replication and expression strategies of RNA viruses to produce vaccine antigens that have been engineered into their genomes. This study has led to significant preclinical testing of many RNA virus vectors against a wide range of pathogens as well as cancer targets. Multiple RNA virus vectors have advanced through preclinical testing to human clinical evaluation. This review will focus on RNA virus vectors designed to express heterologous genes that are packaged into viral particles and have progressed to clinical testing. PMID:25382613

Mogler, Mark A; Kamrud, Kurt I

2015-02-01

414

Vector description of nonlinear magnetization  

International Nuclear Information System (INIS)

The definition of the nonlinear magnetization, which is usually applied in investigating superconductors is discussed in this paper. The nonlinear magnetization of the superconductor, as the response to the alternating magnetic field, is a periodic time function and is determined by the sequence of complex numbers ?n=?n'+i?n'', n=1,2,3,.... The sequence ?n is named harmonic susceptibility. Finding some limits in this definition we propose a new description, substituting the complex sequence ?n with the sequence of real covariant vectors. Such a definition of the nonlinear magnetization, allows to determine function M(t) of an investigated system for an arbitrary initial phase ?o of the inducing magnetic field Hac=hac sin(?t+?o). Vector description, in our opinion, is superior to the complex one in respect of explicitness, simplicity, and universality. Circular diagrams are used to illustrate the new vector description. We also show how the vectors of the harmonic susceptibility can be derived from both numeric calculations and experimental data

415

Improved Locally Adaptive Vector Quantization  

Science.gov (United States)

Several refinements introduced to improve performance of data-compression scheme described in "Adaptive Vector-Quantization Scheme" (NPO-18186). Principal advantages of LAVQ are that complexity and coding time less than those of some other data-compression schemes. Also, does not require priori knowledge of either codebook or statistics of source data.

Cheung, Kar-Ming; Sayano, Masahiro

1994-01-01

416

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

417

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

418

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

419

Distribution amplitudes of vector mesons  

International Nuclear Information System (INIS)

Results are presented for the lowest moment of the distribution amplitude for the K* 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.)

420

Attractor solutions in Lorentz violating scalar-vector-tensor theory  

International Nuclear Information System (INIS)

We investigate properties of attractors for the scalar field in the Lorentz violating scalar-vector-tensor theory of gravity. In this framework, both the effective coupling and potential functions determine the stabilities of the fixed points. In the model, we consider the constants of the slope of the effective coupling and potential functions which lead to the quadratic effective coupling vector with the (inverse) power-law potential. For the case of a purely scalar field, there are only two stable attractor solutions in the inflationary scenario. In the presence of a barotropic fluid, the fluid dominated solution is absent. We find two scaling solutions: the kinetic scaling solution and the scalar field scaling solutions. We show the stable attractors in regions of (?,?) parameter space and in a phase plane plot for different qualitative evolutions. From the standard nucleosynthesis, we derive the constraints for the value of the coupling parameter

421

Fusion rule estimation using vector space methods  

International Nuclear Information System (INIS)

In a system of N sensors, the sensor Sj, j = 1, 2 .... N, outputs Y(j) element-of Re, according to an unknown probability distribution P(Y(j)/X), corresponding to input X element-of [0, 1]. A training n-sample (X1, Y1), (X2, Y2), ..., (Xn, Yn) is given where Yi = (Yi(1), Yi(2), . . . , YiN) such that Yi(j) is the output of Sj in response to input Xi. The problem is to estimate a fusion rule f : Re N ? [0, 1], based on the sample, such that the expected square error is minimized over a family of functions Y that constitute a vector space. The function f* that minimizes the expected error cannot be computed since the underlying densities are unknown, and only an approximation f to f* is feasible. We estimate the sample size sufficient to ensure that f provides a close approximation to f* with a high probability. The advantages of vector space methods are two-fold: (a) the sample size estimate is a simple function of the dimensionality of F, and (b) the estimate f can be easily computed by well-known least square methods in polynomial time. The results are applicable to the classical potential function methods and also (to a recently proposed) special class of sigmoidal feedforward neural networks

422

3D vector flow imaging  

DEFF Research Database (Denmark)

The main purpose of this PhD project is to develop an ultrasonic method for 3D vector flow imaging. The motivation is to advance the field of velocity estimation in ultrasound, which plays an important role in the clinic. The velocity of blood has components in all three spatial dimensions, yet conventional methods can estimate only the axial component. Several approaches for 3D vector velocity estimation have been suggested, but none of these methods have so far produced convincing in vivo results nor have they been adopted by commercial manufacturers. The basis for this project is the Transverse Oscillation (TO) method, which estimates both the axial and the lateral velocity components. The first part of the scientific contribution demonstrates that a commercial implementation of the TO method is feasible. Afterwards, the method is expanded to a phased array geometry, and performance metrics based on the TO fields are suggested. They can be used to optimize the TO method. In the third part, a TO method for 3D vector velocity estimation is proposed. It employs a 2D phased array transducer and decouples the velocity estimation into three velocity components, which are estimated simultaneously based on 5:1 parallel receive beamforming. Simulation results demonstrate the feasibility of the method. In the final part, an experimental investigation of the 3D TO method is presented. Velocity measurements of steady flow were conducted in a flow-rig system, and the data were acquired using an experimental ultrasound scanner and a 2D transducer. The three velocity components along the center line are measured with relative (to the expected values) biases and standard deviations lower than 5 % and 12 %, respectively. At the center of the vessel, the mean and standard deviation of 100 estimated velocity vectors are (vx, vy, vz) = (-0.03, 95, 1.0) ± (9, 6, 1) cm/s compared with the expected (0, 96, 0) cm/s. Afterwards, 3D vector flow images from a cross-sectional plane of the vessel are presented. The out of plane velocities exhibit the expected 2D circular-symmetric parabolic shape. The experimental results verify that the 3D TO method estimates the complete 3D velocity vectors, and that the method is suitable for 3D vector flow imaging.

Pihl, Michael Johannes

2012-01-01

423

The influence of virus-induced changes in plants on aphid vectors: insights from luteovirus pathosystems.  

Science.gov (United States)

Plant virus infection can alter the suitability of host plants for their aphid vectors. Most reports indicate that virus-infected plants are superior hosts for vectors compared to virus-free plants with respect to vector growth rates, fecundity and longevity. Some aphid vectors respond preferentially to virus-infected plants compared to virus-free ones, while others avoid infected plants that are inferior hosts. Thus, it appears vectors can exploit changes in host plant quality associated with viral infection. Enhanced vector performance and preference for virus-infected plants might also be advantageous for viruses by promoting their spread and possibly enhancing their fitness. Our research has focused on two of the most important luteoviruses that infect wheat (Barley yellow dwarf virus), or potato (Potato leafroll virus), and their respective aphid vectors, the bird-cherry oat aphid, Rhopalosiphum padi, and the green peach aphid, Myzus persicae. The work has demonstrated that virus infection of host plants enhances the life history of vectors. Additionally, it has shown that virus infection alters the concentration and relative composition of volatile organic compounds in host plants, that apterae of each vector species settle preferentially on virus-infected plants, and that such responses are mediated by volatile organic compounds. The findings also indicate that plants respond heterogeneously to viral infection and as a result different plant parts change in attractiveness to vectors during infection and vector responses to virus-infected plants are dynamic. Such dynamic responses could enhance or reduce the probability of virus acquisition by individual aphids searching among plants. Finally, our work indicates that compared to non-viruliferous aphids, viruliferous ones are less or not responsive to virus-induced host plant volatiles. Changes in vector responsiveness to plants after vectors acquire virus could impact virus epidemiology by influencing virus spread. The potential implications of these findings for virus ecology and epidemiology are discussed. PMID:21549769

Bosque-Pérez, Nilsa A; Eigenbrode, Sanford D

2011-08-01

424

The Genome of Anopheles darlingi, the main neotropical malaria vector  

Science.gov (United States)

Anopheles darlingi is the principal neotropical malaria vector, responsible for more than a million cases of malaria per year on the American continent. Anopheles darlingi diverged from the African and Asian malaria vectors ?100 million years ago (mya) and successfully adapted to the New World environment. Here we present an annotated reference A. darlingi genome, sequenced from a wild population of males and females collected in the Brazilian Amazon. A total of 10 481 predicted protein-coding genes were annotated, 72% of which have their closest counterpart in Anopheles gambiae and 21% have highest similarity with other mosquito species. In spite of a long period of divergent evolution, conserved gene synteny was observed between A. darlingi and A. gambiae. More than 10 million single nucleotide polymorphisms and short indels with potential use as genetic markers were identified. Transposable elements correspond to 2.3% of the A. darlingi genome. Genes associated with hematophagy, immunity and insecticide resistance, directly involved in vector–human and vector–parasite interactions, were identified and discussed. This study represents the first effort to sequence the genome of a neotropical malaria vector, and opens a new window through which we can contemplate the evolutionary history of anopheline mosquitoes. It also provides valuable information that may lead to novel strategies to reduce malaria transmission on the South American continent. The A. darlingi genome is accessible at www.labinfo.lncc.br/index.php/anopheles-darlingi. PMID:23761445

Marinotti, Osvaldo; Cerqueira, Gustavo C.; de Almeida, Luiz Gonzaga Paula; Ferro, Maria Inês Tiraboschi; Loreto, Elgion Lucio da Silva; Zaha, Arnaldo; Teixeira, Santuza M. R.; Wespiser, Adam R.; Almeida e Silva, Alexandre; Schlindwein, Aline Daiane; Pacheco, Ana Carolina Landim; da Silva, Artur Luiz da Costa; Graveley, Brenton R.; Walenz, Brian P.; Lima, Bruna de Araujo; Ribeiro, Carlos Alexandre Gomes; Nunes-Silva, Carlos Gustavo; de Carvalho, Carlos Roberto; Soares, Célia Maria de Almeida; de Menezes, Claudia Beatriz Afonso; Matiolli, Cleverson; Caffrey, Daniel; Araújo, Demetrius Antonio M.; de Oliveira, Diana Magalhães; Golenbock, Douglas; Grisard, Edmundo Carlos; Fantinatti-Garboggini, Fabiana; de Carvalho, Fabíola Marques; Barcellos, Fernando Gomes; Prosdocimi, Francisco; May, Gemma; de Azevedo Junior, Gilson Martins; Guimarães, Giselle Moura; Goldman, Gustavo Henrique; Padilha, Itácio Q. M.; Batista, Jacqueline da Silva; Ferro, Jesus Aparecido; Ribeiro, José M. C.; Fietto, Juliana Lopes Rangel; Dabbas, Karina Maia; Cerdeira, Louise; Agnez-Lima, Lucymara Fassarella; Brocchi, Marcelo; de Carvalho, Marcos Oliveira; Teixeira, Marcus de Melo; Diniz Maia, Maria de Mascena; Goldman, Maria Helena S.; Cruz Schneider, Maria Paula; Felipe, Maria Sueli Soares; Hungria, Mariangela; Nicolás, Marisa Fabiana; Pereira, Maristela; Montes, Martín Alejandro; Cantão, Maurício E.; Vincentz, Michel; Rafael, Miriam Silva; Silverman, Neal; Stoco, Patrícia Hermes; Souza, Rangel Celso; Vicentini, Renato; Gazzinelli, Ricardo Tostes; Neves, Rogério de Oliveira; Silva, Rosane; Astolfi-Filho, Spartaco; Maciel, Talles Eduardo Ferreira; Ürményi, Turán P.; Tadei, Wanderli Pedro; Camargo, Erney Plessmann; de Vasconcelos, Ana Tereza Ribeiro

2013-01-01

425

Exclusive vector meson production at high energies and gluon saturation  

Science.gov (United States)

We systematically study exclusiv2 diffractive (photo)production of vector mesons (J/?, ?(2s), ?, and ?) off protons in high-energy collisions and investigate whether the production is a sensitive probe of gluon saturation. We confront saturation-based results for diffractive ?(2s) and ? production at HERA and J/? photoproduction with all available data, including recent work from HERA, ALICE, and LHCb, finding good agreement. In particular, we show that the t distribution of differential cross sections of photoproduction of vector mesons offers a unique opportunity to discriminate among saturation and nonsaturation models. This is due to the emergence of a pronounced dip (or multiple dips) in the t distribution of diffractive photoproduction of vector mesons at relatively large, but potentially accessible |t| that can be traced back to the unitarity features of color dipole amplitude in the saturation regime. We show that in saturation models the dips in t distribution recede towards lower |t| with decreasing mass of the vector meson, increasing energy or decreasing Bjorken-x, and decreasing virtuality Q. We provide various predictions for exclusive (photo)production of different vector mesons including the ratio of ?(2s)/J/? at HERA, the LHC, and future colliders.

Armesto, Néstor; Rezaeian, Amir H.

2014-09-01

426

Structural Learning of Attack Vectors for Generating Mutated XSS Attacks  

CERN Document Server

Web applications suffer from cross-site scripting (XSS) attacks that resulting from incomplete or incorrect input sanitization. Learning the structure of attack vectors could enrich the variety of manifestations in generated XSS attacks. In this study, we focus on generating more threatening XSS attacks for the state-of-the-art detection approaches that can find potential XSS vulnerabilities in Web applications, and propose a mechanism for structural learning of attack vectors with the aim of generating mutated XSS attacks in a fully automatic way. Mutated XSS attack generation depends on the analysis of attack vectors and the structural learning mechanism. For the kernel of the learning mechanism, we use a Hidden Markov model (HMM) as the structure of the attack vector model to capture the implicit manner of the attack vector, and this manner is benefited from the syntax meanings that are labeled by the proposed tokenizing mechanism. Bayes theorem is used to determine the number of hidden states in the model...

Wang, Yi-Hsun; Lee, Hahn-Ming; 10.4204/EPTCS.35.2

2010-01-01

427

Towards the genetic manipulation of mosquito disease vectors  

International Nuclear Information System (INIS)

Our research is aimed at developing the technologies necessary to undertake the genetic manipulation of insect vector genomes. In the longer term, we wish to explore the potential that this technology may have for developing novel strategies for the control of vector-borne diseases. The focus of our current research has been to: i) identify and characterise endogenous transposable elements in the genomes of mosquito vectors -research has focussed on identifying both Class I and Class 11 elements and determining their structure and distribution within mosquito genomes; ii) develop and use transfection systems for mosquito cells in culture as a test bed for transformation vectors and promoters - transfection techniques, vector constructs and different promoters driving reporter genes have been utilised to optimise the transformation of both Aedes aegypti and Anopheles gambiae cells in culture; iii) identify putative promoter sequences which are induced in the female mosquito midgut when it takes a blood meal - the Anopheles gambiae trypsin gene locus has been cloned and sequenced and the intergenic regions assessed for their ability to induce reporter gene expression in mosquito gut cells. The progress we have made in each of these areas will be described and discussed in the context of our longer term aim which is to introduce genes coding for antiparasitic agents into mosquito genomes in such a way that they are expressed in the mosquito midgut and disrupt transmission of the malaria parasite. (author)

428

Spinless bosons embedded in a vector Duffin-Kemmer-Petiau oscillator  

International Nuclear Information System (INIS)

Some properties of minimal and nonminimal vector interactions in the Duffin-Kemmer-Petiau (DKP) formalism are discussed. The conservation of the total angular momentum for spherically symmetric nonminimal potentials is derived from its commutation properties with each term of the DKP equation and the proper boundary conditions on the spinors are imposed. It is shown that the space component of the nonminimal vector potential plays a crucial role for the confinement of bosons. The exact solutions for the vector DKP oscillator (nonminimal vector coupling with a linear potential which exhibits an equally spaced energy spectrum in the weak-coupling limit) for spin-0 bosons are presented in a closed form and it is shown that the spectrum exhibits an accidental degeneracy. -- Highlights: ? Nonminimal vector interactions in the Duffin-Kemmer-Petiau (DKP) formalism are discussed. ? The space component of the nonminimal vector linear potential plays a crucial role for the confinement of bosons. ? The exact solutions for the vector DKP oscillator are presented in a closed form.

429

On 3D non-linear vector-vector duality  

International Nuclear Information System (INIS)

We consider the duality between topologically massive and self-dual nonabelian vector fields in three dimensions. In Fock-Schwinger gauge we obtain an explicit, albeit nonlocal, self-dual action equivalent to the topologically massive action. The inverse construction is performed for a restricted class of modified self-dual actions and leads to a topologically massive theory with two interacting gauge fields. (orig.)

430

Vectors and vector-borne diseases of horses.  

Science.gov (United States)

Most diseases of horses with zoonotic importance are transmitted by arthropods. The vectors belong to two very distantly related groups, the chelicerate Ixodidae (Acari = ticks) and the hexapod Diptera (true flies). Almost all relevant species are predestined for transmitting pathogens by their blood-sucking habits. Especially species of Diptera, one of the megadiverse orders of holometabolan insects (ca. 150.000 spp.), affect the health status and performance of horses during the grazing period in summer. The severity of pathological effect depends on the pathogen, but also on the group of vectors and the intensity of the infection or infestation. Dipteran species but also blood-sucking representatives of Acari (Ixodidae) can damage their hosts by sucking blood, causing myiasis, allergy, paralysis and intoxication, and also transmit various bacterial, viral, parasitic, spirochetal and rickettsial diseases to animals and also humans. The aim of this review was to provide extensive information on the infectious diseases transmitted by members of the two arthropod lineages (Ixodidae, Diptera) and a systematic overview of the vectors. For each taxon, usually on the ordinal, family, and genus level a short characterisation is given, allowing non-entomologists easy identification. Additionally, the biology of the relevant species (or genera) is outlined briefly. PMID:23054414

Onmaz, A C; Beutel, R G; Schneeberg, K; Pavaloiu, A N; Komarek, A; van den Hoven, R

2013-03-01

431

Static potentials from an extended gauge symmetry  

International Nuclear Information System (INIS)

Static potentials derived from the inclusion of more than one vector field in a single simple group are calculated. A confinement mechanism including colourful unphysical particle is discussed. (Author)

432

SU(5) Higgs problem with adjoint + vector representations  

International Nuclear Information System (INIS)

Recently Kim has given a general method, using group-invariant orbit parameters, for determining the energy and residual symmetry of the Higgs potential minimum. In this paper we illustrate the method by working out the case of a quartic SU(5) Higgs potential with 5 and 24 higgsons. In this method the Gell-Mann-Slansky conjecture concerning possible little groups of the potential minimum takes a geometric form, which is verified for our case. The results are used to discuss the hierarchical symmetry breaking of SU(5) grand unification theory. We generalize our results to the SU(N) adjoint + vector models, which are all closely related. (orig.)

433

The role of remote sensing and GIS for spatial prediction of vector-borne diseases transmission: a systematic review.  

Science.gov (United States)

There have been several attempts made to the appreciation of remote sensing and GIS for the study of vectors, biodiversity, vector presence, vector abundance and the vector-borne diseases with respect to space and time. This study was made for reviewing and appraising the potential use of remote sensing and GIS applications for spatial prediction of vector-borne diseases transmission. The nature of the presence and the abundance of vectors and vector-borne diseases, disease infection and the disease transmission are not ubiquitous and are confined with geographical, environmental and climatic factors, and are localized. The presence of vectors and vector-borne diseases is most complex in nature, however, it is confined and fueled by the geographical, climatic and environmental factors including man-made factors. The usefulness of the present day availability of the information derived from the satellite data including vegetation indices of canopy cover and its density, soil types, soil moisture, soil texture, soil depth, etc. is integrating the information in the expert GIS engine for the spatial analysis of other geoclimatic and geoenvironmental variables. The present study gives the detailed information on the classical studies of the past and present, and the future role of remote sensing and GIS for the vector-borne diseases control. The ecological modeling directly gives us the relevant information to understand the spatial variation of the vector biodiversity, vector presence, vector abundance and the vector-borne diseases in association with geoclimatic and the environmental variables. The probability map of the geographical distribution and seasonal variations of horizontal and vertical distribution of vector abundance and its association with vector -borne diseases can be obtained with low cost remote sensing and GIS tool with reliable data and speed. PMID:23428518

Palaniyandi, M

2012-12-01

434

VEST: abstract vector calculus simplification in Mathematica  

OpenAIRE

We present a new package, VEST (Vector Einstein Summation Tools), that performs abstract vector calculus computations in Mathematica. Through the use of index notation, VEST is able to reduce three-dimensional scalar and vector expressions of a very general type to a well defined standard form. In addition, utilizing properties of the Levi-Civita symbol, the program can derive types of multi-term vector identities that are not recognized by reduction, subsequently applying t...

Squire, Jonathan; Burby, Joshua; Qin, Hong

2013-01-01

435

Vector bundles and Gromov-Hausdorff distance  

OpenAIRE

We show how to make precise the vague idea that for compact metric spaces that are close together for Gromov-Hausdorff distance, suitable vector bundles on one metric space will have counterpart vector bundles on the other. Our approach employs the Lipschitz constants of projection-valued functions that determine vector bundles. We develop some computational techniques, and we illustrate our ideas with simple specific examples involving vector bundles on the circle, the two-...

Rieffel, Marc A.

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