Conserved charges for black holes in Einstein-Gauss-Bonnet gravity coupled to nonlinear electrodynamics in AdS space

NASA Astrophysics Data System (ADS)

Mišković, Olivera; Olea, Rodrigo

2011-01-01

Motivated by possible applications within the framework of anti-de Sitter gravity/conformal field theory correspondence, charged black holes with AdS asymptotics, which are solutions to Einstein-Gauss-Bonnet gravity in D dimensions, and whose electric field is described by nonlinear electrodynamics are studied. For a topological static black hole ansatz, the field equations are exactly solved in terms of the electromagnetic stress tensor for an arbitrary nonlinear electrodynamic Lagrangian in any dimension D and for arbitrary positive values of Gauss-Bonnet coupling. In particular, this procedure reproduces the black hole metric in Born-Infeld and conformally invariant electrodynamics previously found in the literature. Altogether, it extends to D>4 the four-dimensional solution obtained by Soleng in logarithmic electrodynamics, which comes from vacuum polarization effects. Falloff conditions for the electromagnetic field that ensure the finiteness of the electric charge are also discussed. The black hole mass and vacuum energy as conserved quantities associated to an asymptotic timelike Killing vector are computed using a background-independent regularization of the gravitational action based on the addition of counterterms which are a given polynomial in the intrinsic and extrinsic curvatures.

Conserved charges for black holes in Einstein-Gauss-Bonnet gravity coupled to nonlinear electrodynamics in AdS space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miskovic, Olivera; Olea, Rodrigo; Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso

2011-01-15

Motivated by possible applications within the framework of anti-de Sitter gravity/conformal field theory correspondence, charged black holes with AdS asymptotics, which are solutions to Einstein-Gauss-Bonnet gravity in D dimensions, and whose electric field is described by nonlinear electrodynamics are studied. For a topological static black hole ansatz, the field equations are exactly solved in terms of the electromagnetic stress tensor for an arbitrary nonlinear electrodynamic Lagrangian in any dimension D and for arbitrary positive values of Gauss-Bonnet coupling. In particular, this procedure reproduces the black hole metric in Born-Infeld and conformally invariant electrodynamics previously found in the literature. Altogether, itmore » extends to D>4 the four-dimensional solution obtained by Soleng in logarithmic electrodynamics, which comes from vacuum polarization effects. Falloff conditions for the electromagnetic field that ensure the finiteness of the electric charge are also discussed. The black hole mass and vacuum energy as conserved quantities associated to an asymptotic timelike Killing vector are computed using a background-independent regularization of the gravitational action based on the addition of counterterms which are a given polynomial in the intrinsic and extrinsic curvatures.« less

Killing spinors are Killing vector fields in Riemannian supergeometry

NASA Astrophysics Data System (ADS)

Alekseevsky, D. V.; Cortés, V.; Devchand, C.; Semmelmann, U.

1998-06-01

A supermanifold M is canonically associated to any pseudo-Riemannian spin manifold ( M0, g0). Extending the metric g0 to a field g of bilinear forms g( p) on TpM, pɛM0, the pseudo-Riemannian supergeometry of ( M, g) is formulated as G-structure on M, where G is a supergroup with even part G 0 ≊ Spin(k, l); (k, l) the signature of ( M0, go). Killing vector fields on ( M, g) are, by definition, infinitesimal automorphisms of this G-structure. For every spinor field s there exists a corresponding odd vector field Xs on M. Our main result is that Xs is a Killing vector field on ( M, g) if and only if s is a twistor spinor. In particular, any Killing spinor s defines a Killing vector field Xs.

Projective mappings and dimensions of vector spaces of three types of Killing-Yano tensors on pseudo Riemannian manifolds of constant curvature

NASA Astrophysics Data System (ADS)

Mikeš, Josef; Stepanov, Sergey; Hinterleitner, Irena

2012-07-01

In our paper we have determined the dimension of the space of conformal Killing-Yano tensors and the dimensions of its two subspaces of closed conformal Killing-Yano and Killing-Yano tensors on pseudo Riemannian manifolds of constant curvature. This result is a generalization of well known results on sharp upper bounds of the dimensions of the vector spaces of conformal Killing-Yano, Killing-Yano and concircular vector fields on pseudo Riemannian manifolds of constant curvature.

Vector disformal transformation of cosmological perturbations

NASA Astrophysics Data System (ADS)

Papadopoulos, Vassilis; Zarei, Moslem; Firouzjahi, Hassan; Mukohyama, Shinji

2018-03-01

We study disformal transformations of cosmological perturbations by vector fields in theories invariant under U (1 ) gauge transformations. Three types of vector disformal transformations are considered: (i) disformal transformations by a single timelike vector; (ii) disformal transformations by a single spacelike vector; and (iii) disformal transformations by three spacelike vectors. We show that transformations of type (i) do not change either curvature perturbation or gravitational waves; that those of type (ii) do not change curvature perturbation but change gravitational waves; and that those of type (iii) change both curvature perturbation and gravitational waves. Therefore, coupling matter fields to the metric after disformal transformations of type (ii) or (iii) in principle have observable consequences. While the recent multi-messenger observation of binary neutron stars has singled out a proper disformal frame at the present epoch with a high precision, the result of the present paper may thus help distinguishing disformal frames in the early universe.

Anisotropic mimetic cosmology

NASA Astrophysics Data System (ADS)

Abbassi, M. H.; Jozani, A.; Sepangi, H. R.

2018-06-01

We consider a mimetic set up in which the mimetic scalar is coupled to a vector field. It is shown that such a field with a timelike component does not contribute to the background equations and yet produces healthy isocurvature perturbations with respect to ghost and gradient instabilities in spite of the absence of any propagating curvature perturbations at the level of the quadratic action. We then consider a vector field with spacelike components, which leads to an anisotropic Bianchi universe, and show that the ghost and gradient instabilities are absent in the limit of high momenta and that the propagating curvature perturbations have healthy UV behavior.

On hidden symmetries of extremal Kerr-NUT-AdS-dS black holes

NASA Astrophysics Data System (ADS)

Rasmussen, Jørgen

2011-05-01

It is well known that the Kerr-NUT-AdS-dS black hole admits two linearly independent Killing vectors and possesses a hidden symmetry generated by a rank-2 Killing tensor. The near-horizon geometry of an extremal Kerr-NUT-AdS-dS black hole admits four linearly independent Killing vectors, and we show how the hidden symmetry of the black hole itself is carried over by means of a modified Killing-Yano potential which is given explicitly. We demonstrate that the corresponding Killing tensor of the near-horizon geometry is reducible as it can be expressed in terms of the Casimir operators formed by the four Killing vectors.

Lie algebra of conformal Killing-Yano forms

NASA Astrophysics Data System (ADS)

Ertem, Ümit

2016-06-01

We provide a generalization of the Lie algebra of conformal Killing vector fields to conformal Killing-Yano forms. A new Lie bracket for conformal Killing-Yano forms that corresponds to slightly modified Schouten-Nijenhuis bracket of differential forms is proposed. We show that conformal Killing-Yano forms satisfy a graded Lie algebra in constant curvature manifolds. It is also proven that normal conformal Killing-Yano forms in Einstein manifolds also satisfy a graded Lie algebra. The constructed graded Lie algebras reduce to the graded Lie algebra of Killing-Yano forms and the Lie algebras of conformal Killing and Killing vector fields in special cases.

Proper Conformal Killing Vectors in Kantowski-Sachs Metric

NASA Astrophysics Data System (ADS)

Hussain, Tahir; Farhan, Muhammad

2018-04-01

This paper deals with the existence of proper conformal Killing vectors (CKVs) in Kantowski-Sachs metric. Subject to some integrability conditions, the general form of vector filed generating CKVs and the conformal factor is presented. The integrability conditions are solved generally as well as in some particular cases to show that the non-conformally flat Kantowski-Sachs metric admits two proper CKVs, while it admits a 15-dimensional Lie algebra of CKVs in the case when it becomes conformally flat. The inheriting conformal Killing vectors (ICKVs), which map fluid lines conformally, are also investigated.

Optimal space of linear classical observables for Maxwell k-forms via spacelike and timelike compact de Rham cohomologies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benini, Marco, E-mail: mbenini87@gmail.com, E-mail: mbenini@uni-potsdam.de

Being motivated by open questions in gauge field theories, we consider non-standard de Rham cohomology groups for timelike compact and spacelike compact support systems. These cohomology groups are shown to be isomorphic respectively to the usual de Rham cohomology of a spacelike Cauchy surface and its counterpart with compact support. Furthermore, an analog of the usual Poincaré duality for de Rham cohomology is shown to hold for the case with non-standard supports as well. We apply these results to find optimal spaces of linear observables for analogs of arbitrary degree k of both the vector potential and the Faraday tensor.more » The term optimal has to be intended in the following sense: The spaces of linear observables we consider distinguish between different configurations; in addition to that, there are no redundant observables. This last point in particular heavily relies on the analog of Poincaré duality for the new cohomology groups.« less

Birkhoff theorem and conformal Killing-Yano tensors

NASA Astrophysics Data System (ADS)

Ferrando, Joan Josep; Sáez, Juan Antonio

2015-06-01

We analyze the main geometric conditions imposed by the hypothesis of the Jebsen-Birkhoff theorem. We show that the result (existence of an additional Killing vector) does not necessarily require a three-dimensional isometry group on two-dimensional orbits but only the existence of a conformal Killing-Yano tensor. In this approach the (additional) isometry appears as the known invariant Killing vector that the -metrics admit.

Complete affine connection in the causal boundary: static, spherically symmetric spacetimes

NASA Astrophysics Data System (ADS)

Harris, Steven (Stacey) G.

2017-02-01

The boundary at I^+, future null infinity, for a standard static, spherically symmetric spactime is examined for possible linear connections. Two independent methods are employed, one for treating I^+ as the future causal boundary, and one for treating it as a conformal boundary (the latter is subsumed in the former, which is of greater generality). Both methods provide the same result: a constellation of various possible connections, depending on an arbitrary choice of a certain function, a sort of gauge freedom in obtaining a natural connection on I^+; choosing that function to be constant (for instance) results in a complete connection. Treating I^+ as part of the future causal boundary, the method is to impute affine connections on null hypersurfaces going out to I^+, in terms of a transverse vector field on each null hypersurface (there is much gauge freedom on choice of the transverse vector fields). Treating I^+ as part of a conformal boundary, the method is to make a choice of conformal factor that makes the boundary totally geodesic in the enveloping manifold (there is much gauge freedom in choice of that conformal factor). Similar examination is made of other boundaries, such as timelike infinity and timelike and spacelike singularities. These are much simpler, as they admit a unique connection from a similar limiting process (i.e., no gauge freedom); and that connection is complete.

Cosmological reconstruction and Om diagnostic analysis of Einstein-Aether theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pasqua, Antonio; Chattopadhyay, Surajit; Momeni, Davood

In this paper, we analyze the cosmological models in Einstein-Aether gravity, which is a modified theory of gravity in which a time-like vector field breaks the Lorentz symmetry. We use this formalism to analyse different cosmological models with different behavior of the scale factor. In this analysis, we use a certain functional dependence of the Dark Energy (DE) on the Hubble parameter H . It will be demonstrated that the Aether vector field has a non-trivial effect on these cosmological models. We also perform the Om diagnostic in Einstein-Aether gravity and we fit the parameters of the cosmological models usingmore » recent observational data.« less

Exactly solvable relativistic model with the anomalous interaction

NASA Astrophysics Data System (ADS)

Ferraro, Elena; Messina, Antonino; Nikitin, A. G.

2010-04-01

A special class of Dirac-Pauli equations with time-like vector potentials of an external field is investigated. An exactly solvable relativistic model describing the anomalous interaction of a neutral Dirac fermion with a cylindrically symmetric external electromagnetic field is presented. The related external field is a superposition of the electric field generated by a charged infinite filament and the magnetic field generated by a straight line current. In the nonrelativistic approximation the considered model is reduced to the integrable Pron’ko-Stroganov model.

Hidden symmetries and Lie algebra structures from geometric and supergravity Killing spinors

NASA Astrophysics Data System (ADS)

Açık, Özgür; Ertem, Ümit

2016-08-01

We consider geometric and supergravity Killing spinors and the spinor bilinears constructed out of them. The spinor bilinears of geometric Killing spinors correspond to the antisymmetric generalizations of Killing vector fields which are called Killing-Yano forms. They constitute a Lie superalgebra structure in constant curvature spacetimes. We show that the Dirac currents of geometric Killing spinors satisfy a Lie algebra structure up to a condition on 2-form spinor bilinears. We propose that the spinor bilinears of supergravity Killing spinors give way to different generalizations of Killing vector fields to higher degree forms. It is also shown that those supergravity Killing forms constitute a Lie algebra structure in six- and ten-dimensional cases. For five- and eleven-dimensional cases, the Lie algebra structure depends on an extra condition on supergravity Killing forms.

Existence and stability of circular orbits in static and axisymmetric spacetimes

NASA Astrophysics Data System (ADS)

Jia, Junji; Pang, Xiankai; Yang, Nan

2018-04-01

The existence and stability of timelike and null circular orbits (COs) in the equatorial plane of general static and axisymmetric (SAS) spacetime are investigated in this work. Using the fixed point approach, we first obtained a necessary and sufficient condition for the non-existence of timelike COs. It is then proven that there will always exist timelike COs at large ρ in an asymptotically flat SAS spacetime with a positive ADM mass and moreover, these timelike COs are stable. Some other sufficient conditions on the stability of timelike COs are also solved. We then found the necessary and sufficient condition on the existence of null COs. It is generally shown that the existence of timelike COs in SAS spacetime does not imply the existence of null COs, and vice-versa, regardless whether the spacetime is asymptotically flat or the ADM mass is positive or not. These results are then used to show the existence of timelike COs and their stability in an SAS Einstein-Yang-Mills-Dilaton spacetimes whose metric is not completely known. We also used the theorems to deduce the existence of timelike and null COs in some known SAS spacetimes.

Constraints and stability in vector theories with spontaneous Lorentz violation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bluhm, Robert; Gagne, Nolan L.; Potting, Robertus

2008-06-15

Vector theories with spontaneous Lorentz violation, known as bumblebee models, are examined in flat spacetime using a Hamiltonian constraint analysis. In some of these models, Nambu-Goldstone modes appear with properties similar to photons in electromagnetism. However, depending on the form of the theory, additional modes and constraints can appear that have no counterparts in electromagnetism. An examination of these constraints and additional degrees of freedom, including their nonlinear effects, is made for a variety of models with different kinetic and potential terms, and the results are compared with electromagnetism. The Hamiltonian constraint analysis also permits an investigation of the stabilitymore » of these models. For certain bumblebee theories with a timelike vector, suitable restrictions of the initial-value solutions are identified that yield ghost-free models with a positive Hamiltonian. In each case, the restricted phase space is found to match that of electromagnetism in a nonlinear gauge.« less

Electromagnetic Charge Radius of the Pion at High Precision

NASA Astrophysics Data System (ADS)

Ananthanarayan, B.; Caprini, Irinel; Das, Diganta

2017-09-01

We present a determination of the pion charge radius from high precision data on the pion vector form factor from both timelike and spacelike regions, using a novel formalism based on analyticity and unitarity. At low energies, instead of the poorly known modulus of the form factor, we use its phase, known with high accuracy from Roy equations for π π elastic scattering via the Fermi-Watson theorem. We use also the values of the modulus at several higher timelike energies, where the data from e+e- annihilation and τ decay are mutually consistent, as well as the most recent measurements at spacelike momenta. The experimental uncertainties are implemented by Monte Carlo simulations. The results, which do not rely on a specific parametrization, are optimal for the given input information and do not depend on the unknown phase of the form factor above the first inelastic threshold. Our prediction for the charge radius of the pion is rπ=(0.657 ±0.003 ) fm , which amounts to an increase in precision by a factor of about 2.7 compared to the Particle Data Group average.

Cosmological rotating black holes in five-dimensional fake supergravity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nozawa, Masato; Maeda, Kei-ichi; Waseda Research Institute for Science and Engineering, Okubo 3-4-1, Shinjuku, Tokyo 169-8555

2011-01-15

In recent series of papers, we found an arbitrary dimensional, time-evolving, and spatially inhomogeneous solution in Einstein-Maxwell-dilaton gravity with particular couplings. Similar to the supersymmetric case, the solution can be arbitrarily superposed in spite of nontrivial time-dependence, since the metric is specified by a set of harmonic functions. When each harmonic has a single point source at the center, the solution describes a spherically symmetric black hole with regular Killing horizons and the spacetime approaches asymptotically to the Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmology. We discuss in this paper that in 5 dimensions, this equilibrium condition traces back to the first-order 'Killing spinor'more » equation in 'fake supergravity' coupled to arbitrary U(1) gauge fields and scalars. We present a five-dimensional, asymptotically FLRW, rotating black-hole solution admitting a nontrivial 'Killing spinor', which is a spinning generalization of our previous solution. We argue that the solution admits nondegenerate and rotating Killing horizons in contrast with the supersymmetric solutions. It is shown that the present pseudo-supersymmetric solution admits closed timelike curves around the central singularities. When only one harmonic is time-dependent, the solution oxidizes to 11 dimensions and realizes the dynamically intersecting M2/M2/M2-branes in a rotating Kasner universe. The Kaluza-Klein-type black holes are also discussed.« less

Asymptotic symmetries on Killing horizons

NASA Astrophysics Data System (ADS)

Koga, Jun-Ichirou

2001-12-01

We investigate asymptotic symmetries regularly defined on spherically symmetric Killing horizons in Einstein theory with or without the cosmological constant. These asymptotic symmetries are described by asymptotic Killing vectors, along which the Lie derivatives of perturbed metrics vanish on a Killing horizon. We derive the general form of the asymptotic Killing vectors and find that the group of asymptotic symmetries consists of rigid O(3) rotations of a horizon two-sphere and supertranslations along the null direction on the horizon, which depend arbitrarily on the null coordinate as well as the angular coordinates. By introducing the notion of asymptotic Killing horizons, we also show that local properties of Killing horizons are preserved not only under diffeomorphisms but also under nontrivial transformations generated by the asymptotic symmetry group. Although the asymptotic symmetry group contains the Diff(S1) subgroup, which results from supertranslations dependent only on the null coordinate, it is shown that the Poisson brackets algebra of the conserved charges conjugate to asymptotic Killing vectors does not acquire nontrivial central charges. Finally, by considering extended symmetries, we discuss the fact that unnatural reduction of the symmetry group is necessary in order to obtain the Virasoro algebra with nontrivial central charges, which is not justified when we respect the spherical symmetry of Killing horizons.

All ASD complex and real 4-dimensional Einstein spaces with Λ≠0 admitting a nonnull Killing vector

NASA Astrophysics Data System (ADS)

Chudecki, Adam

2016-12-01

Anti-self-dual (ASD) 4-dimensional complex Einstein spaces with nonzero cosmological constant Λ equipped with a nonnull Killing vector are considered. It is shown that any conformally nonflat metric of such spaces can be always brought to a special form and the Einstein field equations can be reduced to the Boyer-Finley-Plebański equation (Toda field equation). Some alternative forms of the metric are discussed. All possible real slices (neutral, Euclidean and Lorentzian) of ASD complex Einstein spaces with Λ≠0 admitting a nonnull Killing vector are found.

Reviving the shear-free perfect fluid conjecture in general relativity

NASA Astrophysics Data System (ADS)

Sikhonde, Muzikayise E.; Dunsby, Peter K. S.

2017-12-01

Employing a Mathematica symbolic computer algebra package called xTensor, we present (1+3) -covariant special case proofs of the shear-free perfect fluid conjecture in general relativity. We first present the case where the pressure is constant, and where the acceleration is parallel to the vorticity vector. These cases were first presented in their covariant form by Senovilla et al. We then provide a covariant proof for the case where the acceleration and vorticity vectors are orthogonal, which leads to the existence of a Killing vector along the vorticity. This Killing vector satisfies the new constraint equations resulting from the vanishing of the shear. Furthermore, it is shown that in order for the conjecture to be true, this Killing vector must have a vanishing spatially projected directional covariant derivative along the velocity vector field. This in turn implies the existence of another basic vector field along the direction of the vorticity for the conjecture to hold. Finally, we show that in general, there exists a basic vector field parallel to the acceleration for which the conjecture is true.

A Proof of Friedman's Ergosphere Instability for Scalar Waves

NASA Astrophysics Data System (ADS)

Moschidis, Georgios

2018-03-01

Let {(M^{3+1},g)} be a real analytic, stationary and asymptotically flat spacetime with a non-empty ergoregion E and no future event horizon H}^{+. In Friedman (Commun Math Phys 63(3):243-255, 1978), Friedman observed that, on such spacetimes, there exist solutions φ to the wave equation \\squaregφ=0 such that their local energy does not decay to 0 as time increases. In addition, Friedman provided a heuristic argument that the energy of such solutions actually grows to +∞. In this paper, we provide a rigorous proof of Friedman's instability. Our setting is, in fact, more general. We consider smooth spacetimes {(M^{d+1},g)}, for any {d≥2}, not necessarily globally real analytic. We impose only a unique continuation condition for the wave equation across the boundary partial{E} of E on a small neighborhood of a point p\\inpartialE. This condition always holds if {(M,g)} is analytic in that neighborhood of p, but it can also be inferred in the case when {(M,g)} possesses a second Killing field {Φ} such that the span of {Φ} and the stationary Killing field T is timelike on partial{E}. We also allow the spacetimes {(M,g)} under consideration to possess a (possibly empty) future event horizon H}^{+, such that, however, {H+\\cap E=\\emptyset} (excluding, thus, the Kerr exterior family). As an application of our theorem, we infer an instability result for the acoustical wave equation on the hydrodynamic vortex, a phenomenon first investigated numerically by Oliveira et al. in (Phys Rev D 89(12):124008, 2014). Furthermore, as a side benefit of our proof, we provide a derivation, based entirely on the vector field method, of a Carleman-type estimate on the exterior of the ergoregion for a general class of stationary and asymptotically flat spacetimes. Applications of this estimate include a Morawetz-type bound for solutions φ of \\squaregφ=0 with frequency support bounded away from {{ω}=0} and {{ω}=±∞}.

Weakly charged generalized Kerr-NUT-(A)dS spacetimes

NASA Astrophysics Data System (ADS)

Frolov, Valeri P.; Krtouš, Pavel; Kubizňák, David

2017-08-01

We find an explicit solution of the source free Maxwell equations in a generalized Kerr-NUT-(A)dS spacetime in all dimensions. This solution is obtained as a linear combination of the closed conformal Killing-Yano tensor hab, which is present in such a spacetime, and a derivative of the primary Killing vector, associated with hab. For the vanishing cosmological constant the obtained solution reduces to the Wald's electromagnetic field generated from the primary Killing vector.

Every timelike geodesic in Anti-de Sitter spacetime is a circle of the same radius

NASA Astrophysics Data System (ADS)

Sokołowski, Leszek M.; Golda, Zdzisław A.

2016-10-01

In this paper, we refine and analytically prove an old proposition due to Calabi and Markus on the shape of timelike geodesics of anti-de Sitter space in the ambient flat space. We prove that each timelike geodesic forms in the ambient space a circle of the radius determined by Λ, lying on a Euclidean two-plane. Then, we outline an alternative proof for AdS4. We also make a comment on the shape of timelike geodesics in de Sitter space.

9 CFR 113.202 - Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Type 2 Vaccine, Killed Virus. 113.202 Section 113.202 Animals and Animal Products ANIMAL AND PLANT...; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.202 Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus. Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus...

9 CFR 113.202 - Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Type 2 Vaccine, Killed Virus. 113.202 Section 113.202 Animals and Animal Products ANIMAL AND PLANT...; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.202 Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus. Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus...

9 CFR 113.202 - Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Type 2 Vaccine, Killed Virus. 113.202 Section 113.202 Animals and Animal Products ANIMAL AND PLANT...; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.202 Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus. Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus...

9 CFR 113.202 - Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Type 2 Vaccine, Killed Virus. 113.202 Section 113.202 Animals and Animal Products ANIMAL AND PLANT...; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.202 Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus. Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus...

Quantum Fluctuations and Thermodynamic Processes in the Presence of Closed Timelike Curves

NASA Astrophysics Data System (ADS)

Tanaka, Tsunefumi

1997-10-01

A closed timelike curve (CTC) is a closed loop in spacetime whose tangent vector is everywhere timelike. A spacetime which contains CTC's will allow time travel. One of these spacetimes is Grant space. It can be constructed from Minkowski space by imposing periodic boundary conditions in spatial directions and making the boundaries move toward each other. If Hawking's chronology protection conjecture is correct, there must be a physical mechanism preventing the formation of CTC's. Currently the most promising candidate for the chronology protection mechanism is the back reaction of the metric to quantum vacuum fluctuations. In this thesis the quantum fluctuations for a massive scalar field, a self-interacting field, and for a field at nonzero temperature are calculated in Grant space. The stress-energy tensor is found to remain finite everywhere in Grant space for the massive scalar field with sufficiently large field mass. Otherwise it diverges on chronology horizons like the stress-energy tensor for a massless scalar field. If CTC's exist they will have profound effects on physical processes. Causality can be protected even in the presence of CTC's if the self-consistency condition is imposed on all processes. Simple classical thermodynamic processes of a box filled with ideal gas in the presence of CTC's are studied. If a system of boxes is closed, its state does not change as it travels through a region of spacetime with CTC's. But if the system is open, the final state will depend on the interaction with the environment. The second law of thermodynamics is shown to hold for both closed and open systems. A similar problem is investigated at a statistical level for a gas consisting of multiple selves of a single particle in a spacetime with CTC's.

Cosmic string lensing and closed timelike curves

NASA Astrophysics Data System (ADS)

Shlaer, Benjamin; Tye, S.-H. Henry

2005-08-01

In an analysis of the gravitational lensing by two relativistic cosmic strings, we argue that the formation of closed timelike curves proposed by Gott is unstable in the presence of particles (e.g. the cosmic microwave background radiation). Because of the attractorlike behavior of the closed timelike curve, we argue that this instability is very generic. A single graviton or photon in the vicinity, no matter how soft, is sufficient to bend the strings and prevent the formation of closed timelike curves. We also show that the gravitational lensing due to a moving cosmic string is enhanced by its motion, not suppressed.

The problem of exact interior solutions for rotating rigid bodies in general relativity

NASA Technical Reports Server (NTRS)

Wahlquist, H. D.

1993-01-01

The (3 + 1) dyadic formalism for timelike congruences is applied to derive interior solutions for stationary, axisymmetric, rigidly rotating bodies. In this approach the mathematics is formulated in terms of three-space-covariant, first-order, vector-dyadic, differential equations for a and Omega, the acceleration and angular velocity three-vectors of the rigid body; for T, the stress dyadic of the matter; and for A and B, the 'electric' and 'magnetic' Weyl curvature dyadics which describe the gravitational field. It is shown how an appropriate ansatz for the forms of these dyadics can be used to discover exact rotating interior solutions such as the perfect fluid solution first published in 1968. By incorporating anisotropic stresses, a generalization is found of that previous solution and, in addition, a very simple new solution that can only exist in toroidal configurations.

Ricci time in the Lemaître-Tolman model and the block universe

NASA Astrophysics Data System (ADS)

Elmahalawy, Yasser; Hellaby, Charles; Ellis, George F. R.

2015-10-01

It is common to think of our universe according to the "block universe" concept, which says that spacetime consists of many "stacked" three-surfaces, labelled by some kind of proper time, . Standard ideas do not distinguish past and future, but Ellis' "evolving block universe" tries to make a fundamental distinction. One proposal for this proper time is the proper time measured along the timelike Ricci eigenlines, starting from the big bang. This work investigates the shape of the "Ricci time" surfaces relative to the the null surfaces. We use the Lemaître-Tolman metric as our inhomogeneous spacetime model, and we find the necessary and sufficient conditions for these constant surfaces, , to be spacelike or timelike. Furthermore, we look at the effect of strong gravity domains by determining the location of timelike S regions relative to apparent horizons. We find that constant Ricci time surfaces are always spacelike near the big bang, while at late times (near the crunch or the extreme far future), they are only timelike under special circumstances. At intermediate times, timelike S regions are common unless the variation of the bang time is restricted. The regions where these surfaces become timelike are often adjacent to apparent horizons, but always outside them, and in particular timelike S regions do not occur inside the horizons of black-hole-like models.

Combining Synthetic Human Odours and Low-Cost Electrocuting Grids to Attract and Kill Outdoor-Biting Mosquitoes: Field and Semi-Field Evaluation of an Improved Mosquito Landing Box

PubMed Central

Matowo, Nancy S.; Koekemoer, Lizette L.; Moore, Sarah J.; Mmbando, Arnold S.; Mapua, Salum A.; Coetzee, Maureen; Okumu, Fredros O.

2016-01-01

Background On-going malaria transmission is increasingly mediated by outdoor-biting vectors, especially where indoor insecticidal interventions such as long-lasting insecticide treated nets (LLINs) are widespread. Often, the vectors are also physiologically resistant to insecticides, presenting major obstacles for elimination. We tested a combination of electrocuting grids with synthetic odours as an alternative killing mechanism against outdoor-biting mosquitoes. Methods An odour-baited device, the Mosquito Landing Box (MLB), was improved by fitting it with low-cost electrocuting grids to instantly kill mosquitoes attracted to the odour lure, and automated photo switch to activate attractant-dispensing and mosquito-killing systems between dusk and dawn. MLBs fitted with one, two or three electrocuting grids were compared outdoors in a malaria endemic village in Tanzania, where vectors had lost susceptibility to pyrethroids. MLBs with three grids were also tested in a large semi-field cage (9.6×9.6×4.5m), to assess effects on biting-densities of laboratory-reared Anopheles arabiensis on volunteers sitting near MLBs. Results Significantly more mosquitoes were killed when MLBs had two or three grids, than one grid in wet and dry seasons (P<0.05). The MLBs were highly efficient against Mansonia species and malaria vector, An. arabiensis. Of all mosquitoes, 99% were non-blood fed, suggesting host-seeking status. In the semi-field, the MLBs reduced mean number of malaria mosquitoes attempting to bite humans fourfold. Conclusion The improved odour-baited MLBs effectively kill outdoor-biting malaria vector mosquitoes that are behaviourally and physiologically resistant to insecticidal interventions e.g. LLINs. The MLBs reduce human-biting vector densities even when used close to humans, and are insecticide-free, hence potentially antiresistance. The devices could either be used as surveillance tools or complementary mosquito control interventions to accelerate malaria elimination where outdoor transmission is significant. PMID:26789733

9 CFR 113.202 - Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Canine Hepatitis and Canine Adenovirus...; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.202 Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus. Canine Hepatitis and Canine Adenovirus Type 2 Vaccine, Killed Virus...

Maximizers in Lipschitz spacetimes are either timelike or null

NASA Astrophysics Data System (ADS)

Graf, Melanie; Ling, Eric

2018-04-01

We prove that causal maximizers in C 0,1 spacetimes are either timelike or null. This question was posed in Sämann and Steinbauer (2017 arXiv:1710.10887) since bubbling regions in C0, α spacetimes (α <1 ) can produce causal maximizers that contain a segment which is timelike and a segment which is null, see Chruściel and Grant (2012 Class. Quantum Grav. 29 145001). While C 0,1 spacetimes do not produce bubbling regions, the causal character of maximizers for spacetimes with regularity at least C 0,1 but less than C 1,1 was unknown until now. As an application we show that timelike geodesically complete spacetimes are C 0,1-inextendible.

Reaction μ-+6Li-->3H+3H+νμ and the axial current form factor in the timelike region

NASA Astrophysics Data System (ADS)

Mintz, S. L.

1983-09-01

The differential muon-capture rate dΓdET is obtained for the reaction μ-+6Li-->3H+3H+νμ over the allowed range of ET, the tritium energy, for two assumptions concerning the behavior of FA, the axial current form factor, in the timelike region; analytic continuation from the spacelike region and mirror behavior, FA(q2, timelike)=FA(q2, spacelike). The values of dΓdET under these two assumptions are found to vary substantially in the timelike region as a function of the mass MA in the dipole fit to FA. Values of dΓdET are given for MA2=2mπ2, 4.95mπ2, and 8mπ2. NUCLEAR REACTIONS Muon capture 6Li(μ-, νμ)3H3H, Γ, dΓdET calculated for two assumptions concerning the axial current form factor behavior in timelike region.

The branching ratio ω → π ^+π ^- revisited

NASA Astrophysics Data System (ADS)

Hanhart, C.; Holz, S.; Kubis, B.; Kupść, A.; Wirzba, A.; Xiao, C. W.

2017-02-01

We analyze the most recent data for the pion vector form factor in the timelike region, employing a model-independent approach based on dispersion theory. We confirm earlier observations about the inconsistency of different modern high-precision data sets. Excluding the BaBar data, we find an updated value for the isospin-violating branching ratio B(ω → π ^+π ^-) = (1.46± 0.08) × 10^{-2}. As a side result, we also extract an improved value for the pion vector or charge radius, √{< r_V^2rangle } = 0.6603(5)(4) {fm}, where the first uncertainty is statistical as derived from the fit, while the second estimates the possible size of nonuniversal radiative corrections. In addition, we demonstrate that modern high-quality data for the decay η '→ π ^+π ^-γ will allow for an even improved determination of the transition strength ω → π ^+π ^-.

The Plasmodium bottleneck: malaria parasite losses in the mosquito vector

PubMed Central

Smith, Ryan C; Vega-Rodríguez, Joel; Jacobs-Lorena, Marcelo

2014-01-01

Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission. PMID:25185005

A general theory of linear cosmological perturbations: scalar-tensor and vector-tensor theories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lagos, Macarena; Baker, Tessa; Ferreira, Pedro G.

We present a method for parametrizing linear cosmological perturbations of theories of gravity, around homogeneous and isotropic backgrounds. The method is sufficiently general and systematic that it can be applied to theories with any degrees of freedom (DoFs) and arbitrary gauge symmetries. In this paper, we focus on scalar-tensor and vector-tensor theories, invariant under linear coordinate transformations. In the case of scalar-tensor theories, we use our framework to recover the simple parametrizations of linearized Horndeski and ''Beyond Horndeski'' theories, and also find higher-derivative corrections. In the case of vector-tensor theories, we first construct the most general quadratic action for perturbationsmore » that leads to second-order equations of motion, which propagates two scalar DoFs. Then we specialize to the case in which the vector field is time-like (à la Einstein-Aether gravity), where the theory only propagates one scalar DoF. As a result, we identify the complete forms of the quadratic actions for perturbations, and the number of free parameters that need to be defined, to cosmologically characterize these two broad classes of theories.« less

Applications of invariants in general relativity

NASA Astrophysics Data System (ADS)

Pelavas, Nicos

This thesis explores various kinds of invariants and their use in general relativity. To start, the simplest invariants, those polynomial in the Riemann tensor, are examined and the currently accepted Carminati-Zakhary set is compared to the Carminati-McLenaghan set. A number of algebraic relations linking the two sets are given. The concept of gravitational entropy, as proposed by Penrose, has some physically appealing properties which have motivated attempts to quantify this notion using various invariants. We study this in the context of self-similar spacetimes. A general result is obtained which gives the Lie derivative of any invariant or ratio of invariants along a homothetic trajectory. A direct application of this result shows that the currently used gravitational epoch function fails to satisfy certain criteria. Based on this work, candidates for a gravitational epoch function are proposed that behave accordingly in these models. The instantaneous ergo surface in the Kerr solution is studied and shown to possess conical points at the poles when embedded in three dimensional Euclidean space. These intrinsic singularities had remained undiscovered for a generation. We generalize the Gauss-Bonnet theorem to accommodate these points and use it to compute a topological invariant, the Euler characteristic, for this surface. Interest in solutions admitting a cosmological constant has prompted us to study ergo surfaces in stationary non-asymptotically flat spacetimes. In these cases we show that there is in fact a family of ergo surfaces. By using a kinematic invariant constructed from timelike Killing vectors we try to find a preferred ergo surface. We illustrate to what extent this invariant fails to provide such a measure.

9 CFR 113.207 - Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Encephalomyelitis Vaccine, Eastern... PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.207 Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus. Encephalomyelitis Vaccine, Eastern, Western, and...

9 CFR 113.207 - Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Encephalomyelitis Vaccine, Eastern... PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.207 Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus. Encephalomyelitis Vaccine, Eastern, Western, and...

9 CFR 113.207 - Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Encephalomyelitis Vaccine, Eastern... PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.207 Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus. Encephalomyelitis Vaccine, Eastern, Western, and...

9 CFR 113.207 - Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Encephalomyelitis Vaccine, Eastern... PRODUCTS; ORGANISMS AND VECTORS STANDARD REQUIREMENTS Killed Virus Vaccines § 113.207 Encephalomyelitis Vaccine, Eastern, Western, and Venezuelan, Killed Virus. Encephalomyelitis Vaccine, Eastern, Western, and...

Timelike Momenta In Quantum Electrodynamics

DOE R&D Accomplishments Database

Brodsky, S. J.; Ting, S. C. C.

1965-12-01

In this note we discuss the possibility of studying the quantum electrodynamics of timelike photon propagators in muon or electron pair production by incident high energy muon or electron beams from presently available proton or electron accelerators.

Parsley: a Command-Line Parser for Astronomical Applications

NASA Astrophysics Data System (ADS)

Deich, William

Parsley is a sophisticated keyword + value parser, packaged as a library of routines that offers an easy method for providing command-line arguments to programs. It makes it easy for the user to enter values, and it makes it easy for the programmer to collect and validate the user's entries. Parsley is tuned for astronomical applications: for example, dates entered in Julian, Modified Julian, calendar, or several other formats are all recognized without special effort by the user or by the programmer; angles can be entered using decimal degrees or dd:mm:ss; time-like intervals as decimal hours, hh:mm:ss, or a variety of other units. Vectors of data are accepted as readily as scalars.

Innovative Techniques for Estimating Illegal Activities in a Human-Wildlife-Management Conflict

PubMed Central

Cross, Paul; St. John, Freya A. V.; Khan, Saira; Petroczi, Andrea

2013-01-01

Effective management of biological resources is contingent upon stakeholder compliance with rules. With respect to disease management, partial compliance can undermine attempts to control diseases within human and wildlife populations. Estimating non-compliance is notoriously problematic as rule-breakers may be disinclined to admit to transgressions. However, reliable estimates of rule-breaking are critical to policy design. The European badger (Meles meles) is considered an important vector in the transmission and maintenance of bovine tuberculosis (bTB) in cattle herds. Land managers in high bTB prevalence areas of the UK can cull badgers under license. However, badgers are also known to be killed illegally. The extent of illegal badger killing is currently unknown. Herein we report on the application of three innovative techniques (Randomized Response Technique (RRT); projective questioning (PQ); brief implicit association test (BIAT)) for investigating illegal badger killing by livestock farmers across Wales. RRT estimated that 10.4% of farmers killed badgers in the 12 months preceding the study. Projective questioning responses and implicit associations relate to farmers' badger killing behavior reported via RRT. Studies evaluating the efficacy of mammal vector culling and vaccination programs should incorporate estimates of non-compliance. Mitigating the conflict concerning badgers as a vector of bTB requires cross-disciplinary scientific research, departure from deep-rooted positions, and the political will to implement evidence-based management. PMID:23341973

Innovative techniques for estimating illegal activities in a human-wildlife-management conflict.

PubMed

Cross, Paul; St John, Freya A V; Khan, Saira; Petroczi, Andrea

2013-01-01

Effective management of biological resources is contingent upon stakeholder compliance with rules. With respect to disease management, partial compliance can undermine attempts to control diseases within human and wildlife populations. Estimating non-compliance is notoriously problematic as rule-breakers may be disinclined to admit to transgressions. However, reliable estimates of rule-breaking are critical to policy design. The European badger (Meles meles) is considered an important vector in the transmission and maintenance of bovine tuberculosis (bTB) in cattle herds. Land managers in high bTB prevalence areas of the UK can cull badgers under license. However, badgers are also known to be killed illegally. The extent of illegal badger killing is currently unknown. Herein we report on the application of three innovative techniques (Randomized Response Technique (RRT); projective questioning (PQ); brief implicit association test (BIAT)) for investigating illegal badger killing by livestock farmers across Wales. RRT estimated that 10.4% of farmers killed badgers in the 12 months preceding the study. Projective questioning responses and implicit associations relate to farmers' badger killing behavior reported via RRT. Studies evaluating the efficacy of mammal vector culling and vaccination programs should incorporate estimates of non-compliance. Mitigating the conflict concerning badgers as a vector of bTB requires cross-disciplinary scientific research, departure from deep-rooted positions, and the political will to implement evidence-based management.

The potential for fungal biopesticides to reduce malaria transmission under diverse environmental conditions.

PubMed

Heinig, R L; Paaijmans, Krijn P; Hancock, Penelope A; Thomas, Matthew B

2015-12-01

The effectiveness of conventional malaria vector control is being threatened by the spread of insecticide resistance. One promising alternative to chemicals is the use of naturally-occurring insect-killing fungi. Numerous laboratory studies have shown that isolates of fungal pathogens such as Beauveria bassiana can infect and kill adult mosquitoes, including those resistant to chemical insecticides.Unlike chemical insecticides, fungi may take up to a week or more to kill mosquitoes following exposure. This slow kill speed can still reduce malaria transmission because the malaria parasite itself takes at least eight days to complete its development within the mosquito. However, both fungal virulence and parasite development rate are strongly temperature-dependent, so it is possible that biopesticide efficacy could vary across different transmission environments.We examined the virulence of a candidate fungal isolate against two key malaria vectors at temperatures from 10-34 °C. Regardless of temperature, the fungus killed more than 90% of exposed mosquitoes within the predicted duration of the malarial extrinsic incubation period, a result that was robust to realistic diurnal temperature variation.We then incorporated temperature sensitivities of a suite of mosquito, parasite and fungus life-history traits that are important determinants of malaria transmission into a stage-structured malaria transmission model. The model predicted that, at achievable daily fungal infection rates, fungal biopesticides have the potential to deliver substantial reductions in the density of malaria-infectious mosquitoes across all temperatures representative of malaria transmission environments. Synthesis and applications . Our study combines empirical data and theoretical modelling to prospectively evaluate the potential of fungal biopesticides to control adult malaria vectors. Our results suggest that Beauveria bassiana could be a potent tool for malaria control and support further development of fungal biopesticides to manage infectious disease vectors.

Killing-Yano tensors of order n - 1

NASA Astrophysics Data System (ADS)

Batista, Carlos

2014-08-01

The properties of a Killing-Yano tensor of order n-1 in an n-dimensional manifold are investigated. The integrability conditions are worked out and all metrics admitting a Killing-Yano tensor of order n-1 are found. A connection between such tensors and a generalization of the concept of angular momentum is pointed out. A theorem on how to generate closed conformal Killing vectors using the symmetries of a manifold is proved and used to find all Killing-Yano tensors of order n-1 of a maximally symmetric space.

Integrability of geodesics and action-angle variables in Sasaki-Einstein space T^{1,1}

NASA Astrophysics Data System (ADS)

Visinescu, Mihai

2016-09-01

We briefly describe the construction of Stäkel-Killing and Killing-Yano tensors on toric Sasaki-Einstein manifolds without working out intricate generalized Killing equations. The integrals of geodesic motions are expressed in terms of Killing vectors and Killing-Yano tensors of the homogeneous Sasaki-Einstein space T^{1,1}. We discuss the integrability of geodesics and construct explicitly the action-angle variables. Two pairs of frequencies of the geodesic motions are resonant giving way to chaotic behavior when the system is perturbed.

Infinite-Dimensional Symmetry Algebras as a Help Toward Solutions of the Self-Dual Field Equations with One Killing Vector

NASA Astrophysics Data System (ADS)

Finley, Daniel; McIver, John K.

2002-12-01

The sDiff(2) Toda equation determines all self-dual, vacuum solutions of the Einstein field equations with one rotational Killing vector. Some history of the searches for non-trivial solutions is given, including those that begin with the limit as n → ∞ of the An Toda lattice equations. That approach is applied here to the known prolongation structure for the Toda lattice, hoping to use Bäcklund transformations to generate new solutions. Although this attempt has not yet succeeded, new faithful (tangent-vector) realizations of A∞ are described, and a direct approach via the continuum Lie algebras of Saveliev and Leznov is given.

Geodesic motion around traversable wormholes supported by a massless conformally coupled scalar field

NASA Astrophysics Data System (ADS)

Willenborg, Felix; Grunau, Saskia; Kleihaus, Burkhard; Kunz, Jutta

2018-06-01

We consider a traversable wormhole solution of Einstein's gravity conformally coupled to a massless scalar field, a solution derived by Barcelo and Visser based on the Janis-Newman-Winicour-Wyman spacetime. We study the geodesic motion of timelike and spacelike particles in this spacetime. We solve the equations of motion analytically in terms of the Weierstraß functions and discuss all possible orbit types and their parameter dependence. Interestingly, bound orbits occur for timelike geodesics only in one of the two worlds. Moreover, under no conditions there exist timelike two world bound orbits.

Null conformal Killing-Yano tensors and Birkhoff theorem

NASA Astrophysics Data System (ADS)

Ferrando, Joan Josep; Sáez, Juan Antonio

2016-04-01

We study the space-times admitting a null conformal Killing-Yano tensor whose divergence defines a Killing vector. We analyze the similarities and differences with the recently studied non null case (Ferrando and Sáez in Gen Relativ Gravit 47:1911, 2015). The results by Barnes concerning the Birkhoff theorem for the case of null orbits are analyzed and generalized.

Reference results for time-like evolution up to

NASA Astrophysics Data System (ADS)

Bertone, Valerio; Carrazza, Stefano; Nocera, Emanuele R.

2015-03-01

We present high-precision numerical results for time-like Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution in the factorisation scheme, for the first time up to next-to-next-to-leading order accuracy in quantum chromodynamics. First, we scrutinise the analytical expressions of the splitting functions available in the literature, in both x and N space, and check their mutual consistency. Second, we implement time-like evolution in two publicly available, entirely independent and conceptually different numerical codes, in x and N space respectively: the already existing APFEL code, which has been updated with time-like evolution, and the new MELA code, which has been specifically developed to perform the study in this work. Third, by means of a model for fragmentation functions, we provide results for the evolution in different factorisation schemes, for different ratios between renormalisation and factorisation scales and at different final scales. Our results are collected in the format of benchmark tables, which could be used as a reference for global determinations of fragmentation functions in the future.

Chapter 5. Hidden Symmetry and Exact Solutions in Einstein Gravity

NASA Astrophysics Data System (ADS)

Yasui, Y.; Houri, T.

Conformal Killing-Yano tensors are introduced as ageneralization of Killing vectors. They describe symmetries of higher-dimensional rotating black holes. In particular, a rank-2 closed conformal Killing-Yano tensor generates the tower of both hidden symmetries and isometries. We review a classification of higher-dimensional spacetimes admitting such a tensor, and present exact solutions to the Einstein equations for these spacetimes.

Global structure of Gott's two-string spacetime

NASA Astrophysics Data System (ADS)

Cutler, Curt

1992-01-01

Gott has recently obtained exact solutions to Einstein's equation representing two infinitely long, straight cosmic strings that gravitationally scatter off each other. A remarkable feature of these solutions is that they contain closed timelike curves when the relative velocity of the strings is sufficiently high. In this paper we elucidate the global structure of Gott's two-string spacetime. In particular, we prove that the closed timelike curves are confined to a certain region of the spacetime, and that the spacetime contains complete spacelike, edgeless, achronal hypersurfaces, from which the causality-violating regions may be said to evolve. We then explicitly determine the boundary of the region containing closed timelike curves.

Higher spin realization of the DS/CFT correspondence

NASA Astrophysics Data System (ADS)

Anninos, Dionysios; Hartman, Thomas; Strominger, Andrew

2017-01-01

We conjecture that Vasiliev’s theory of higher spin gravity in four-dimensional de Sitter space (dS4) is holographically dual to a three-dimensional conformal field theory (CFT3) living on the spacelike boundary of dS4 at future timelike infinity. The CFT3 is the Euclidean Sp(N) vector model with anticommuting scalars. The free CFT3 flows under a double-trace deformation to an interacting CFT3 in the IR. We argue that both CFTs are dual to Vasiliev dS4 gravity but with different future boundary conditions on the bulk scalar field. Our analysis rests heavily on analytic continuations of bulk and boundary correlators in the proposed duality relating the O(N) model with Vasiliev gravity in AdS4.

A lattice calculation of the hadronic vacuum polarization contribution to (g - 2)µ

NASA Astrophysics Data System (ADS)

Della Morte, M.; Francis, A.; Gérardin, A.; Gülpers, V.; Herdoíza, G.; von Hippel, G.; Horch, H.; Jäger, B.; Meyer, H. B.; Nyffeler, A.; Wittig, H.

2018-03-01

We present results of calculations of the hadronic vacuum polarisation contribution to the muon anomalous magnetic moment. Specifically, we focus on controlling the infrared regime of the vacuum polarisation function. Our results are corrected for finite-size effects by combining the Gounaris-Sakurai parameterisation of the timelike pion form factor with the Lüscher formalism. The impact of quark-disconnected diagrams and the precision of the scale determination is discussed and included in our final result in two-flavour QCD, which carries an overall uncertainty of 6%. We present preliminary results computed on ensembles with Nf = 2 + 1 dynamical flavours and discuss how the long-distance contribution can be accurately constrained by a dedicated spectrum calculation in the iso-vector channel.

Proper projective symmetry in LRS Bianchi type V spacetimes

NASA Astrophysics Data System (ADS)

Shabbir, Ghulam; Mahomed, K. S.; Mahomed, F. M.; Moitsheki, R. J.

2018-04-01

In this paper, we investigate proper projective vector fields of locally rotationally symmetric (LRS) Bianchi type V spacetimes using direct integration and algebraic techniques. Despite the non-degeneracy in the Riemann tensor eigenvalues, we classify proper Bianchi type V spacetimes and show that the above spacetimes do not admit proper projective vector fields. Here, in all the cases projective vector fields are Killing vector fields.

Einstein-aether theory with a Maxwell field: General formalism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balakin, Alexander B., E-mail: Alexander.Balakin@kpfu.ru; Lemos, José P.S., E-mail: joselemos@ist.utl.pt

We extend the Einstein-aether theory to include the Maxwell field in a nontrivial manner by taking into account its interaction with the time-like unit vector field characterizing the aether. We also include a generic matter term. We present a model with a Lagrangian that includes cross-terms linear and quadratic in the Maxwell tensor, linear and quadratic in the covariant derivative of the aether velocity four-vector, linear in its second covariant derivative and in the Riemann tensor. We decompose these terms with respect to the irreducible parts of the covariant derivative of the aether velocity, namely, the acceleration four-vector, the shearmore » and vorticity tensors, and the expansion scalar. Furthermore, we discuss the influence of an aether non-uniform motion on the polarization and magnetization of the matter in such an aether environment, as well as on its dielectric and magnetic properties. The total self-consistent system of equations for the electromagnetic and the gravitational fields, and the dynamic equations for the unit vector aether field are obtained. Possible applications of this system are discussed. Based on the principles of effective field theories, we display in an appendix all the terms up to fourth order in derivative operators that can be considered in a Lagrangian that includes the metric, the electromagnetic and the aether fields.« less

Blocking transmission of vector-borne diseases.

PubMed

Schorderet-Weber, Sandra; Noack, Sandra; Selzer, Paul M; Kaminsky, Ronald

2017-04-01

Vector-borne diseases are responsible for significant health problems in humans, as well as in companion and farm animals. Killing the vectors with ectoparasitic drugs before they have the opportunity to pass on their pathogens could be the ideal way to prevent vector borne diseases. Blocking of transmission might work when transmission is delayed during blood meal, as often happens in ticks. The recently described systemic isoxazolines have been shown to successfully prevent disease transmission under conditions of delayed pathogen transfer. However, if the pathogen is transmitted immediately at bite as it is the case with most insects, blocking transmission becomes only possible if ectoparasiticides prevent the vector from landing on or, at least, from biting the host. Chemical entities exhibiting repellent activity in addition to fast killing, like pyrethroids, could prevent pathogen transmission even in cases of immediate transfer. Successful blocking depends on effective action in the context of the extremely diverse life-cycles of vectors and vector-borne pathogens of medical and veterinary importance which are summarized in this review. This complexity leads to important parameters to consider for ectoparasiticide research and when considering the ideal drug profile for preventing disease transmission. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Killing-Yano symmetry of Kaluza-Klein black holes in five dimensions

NASA Astrophysics Data System (ADS)

Houri, Tsuyoshi; Yamamoto, Kei

2013-04-01

Using a generalized Killing-Yano equation in the presence of torsion, spacetime metrics admitting a rank-2 generalized Killing-Yano tensor are investigated in five dimensions under the assumption that its eigenvector associated with the zero eigenvalue is a Killing vector field. It is shown that such metrics are classified into three types and the corresponding local expressions are given explicitly. It is also shown that they cover some classes of charged, rotating Kaluza-Klein black hole solutions of minimal supergravity and Abelian heterotic supergravity.

Concircular vector fields on Lorentzian manifold of Bianchi type-I spacetimes

NASA Astrophysics Data System (ADS)

Mahmood, Amjad; Ali, Ahmad T.; Khan, Suhail

2018-04-01

Our aim in this paper is to obtain concircular vector fields (CVFs) on the Lorentzian manifold of Bianchi type-I spacetimes. For this purpose, two different sets of coupled partial differential equations comprising ten equations each are obtained. The first ten equations, known as conformal Killing equations are solved completely and components of conformal Killing vector fields (CKVFs) are obtained in different possible cases. These CKVFs are then substituted into second set of ten differential equations to obtain CVFs. It comes out that Bianchi type-I spacetimes admit four-, five-, six-, seven- or 15-dimensional CVFs for particular choices of the metric functions. In many cases, the CKVFs of a particular metric are same as CVFs while there exists few cases where proper CKVFs are not CVFs.

Uniqueness of complete maximal hypersurfaces in spatially parabolic generalized Robertson-Walker spacetimes

NASA Astrophysics Data System (ADS)

Romero, Alfonso; Rubio, Rafael M.; Salamanca, Juan J.

2013-06-01

A new technique for the study of noncompact complete spacelike hypersurfaces in generalized Robertson-Walker (GRW) spacetimes whose fiber is a parabolic Riemannian manifold is introduced. This class of spacetimes allows us to model open universes which extend to spacelike closed GRW spacetimes from the viewpoint of the geometric analysis of the fiber, and which, unlike those spacetimes, could be compatible with the holographic principle. First, under reasonable assumptions on the restriction of the warping function to the spacelike hypersurface and on the hyperbolic angle between the unit normal vector field and a certain timelike vector field, a complete spacelike hypersurface in a spatially parabolic GRW spacetime is shown to be parabolic, and the existence of a simply connected parabolic spacelike hypersurface in a GRW spacetime also leads to the parabolicity of its fiber. Then, all the complete maximal hypersurfaces in spatially parabolic GRW spacetimes are determined in several cases, extending, in particular, to this family of open cosmological models several well-known uniqueness results for the case of spatially closed GRW spacetimes. Moreover, new Calabi-Bernstein problems are solved.

Asymptotic behavior of dynamical variables and naked singularity formation in spherically symmetric gravitational collapse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawakami, Hayato; Mitsuda, Eiji; Nambu, Yasusada

In considering the gravitational collapse of matter, it is an important problem to clarify what kind of conditions leads to the formation of naked singularity. For this purpose, we apply the 1+3 orthonormal frame formalism introduced by Uggla et al. to the spherically symmetric gravitational collapse of a perfect fluid. This formalism allows us to construct an autonomous system of evolution and constraint equations for scale-invariant dynamical variables normalized by the volume expansion rate of the timelike orthonormal frame vector. We investigate the asymptotic evolution of such dynamical variables towards the formation of a central singularity and present a conjecturemore » that the steep spatial gradient for the normalized density function is a characteristic of the naked singularity formation.« less

Control of Malaria Vector Mosquitoes by Insecticide-Treated Combinations of Window Screens and Eave Baffles.

PubMed

Killeen, Gerry F; Masalu, John P; Chinula, Dingani; Fotakis, Emmanouil A; Kavishe, Deogratius R; Malone, David; Okumu, Fredros

2017-05-01

We assessed window screens and eave baffles (WSEBs), which enable mosquitoes to enter but not exit houses, as an alternative to indoor residual spraying (IRS) for malaria vector control. WSEBs treated with water, the pyrethroid lambda-cyhalothrin, or the organophosphate pirimiphos-methyl, with and without a binding agent for increasing insecticide persistence on netting, were compared with IRS in experimental huts. Compared with IRS containing the same insecticide, WSEBs killed similar proportions of Anopheles funestus mosquitoes that were resistant to pyrethroids, carbamates and organochlorines and greater proportions of pyrethroid-resistant, early exiting An. arabiensis mosquitoes. WSEBs with pirimiphos-methyl killed greater proportions of both vectors than lambda-cyhalothrin or lambda-cyhalothrin plus pirimiphos-methyl and were equally efficacious when combined with binding agent. WSEBs required far less insecticide than IRS, and binding agents might enhance durability. WSEBs might enable affordable deployment of insecticide combinations to mitigate against physiologic insecticide resistance and improve control of behaviorally resistant, early exiting vectors.

First integrals of motion in a gauge covariant framework, Killing-Maxwell system and quantum anomalies

NASA Astrophysics Data System (ADS)

Visinescu, M.

2012-10-01

Hidden symmetries in a covariant Hamiltonian framework are investigated. The special role of the Stackel-Killing and Killing-Yano tensors is pointed out. The covariant phase-space is extended to include external gauge fields and scalar potentials. We investigate the possibility for a higher-order symmetry to survive when the electromagnetic interactions are taken into account. Aconcrete realization of this possibility is given by the Killing-Maxwell system. The classical conserved quantities do not generally transfer to the quantized systems producing quantum gravitational anomalies. As a rule the conformal extension of the Killing vectors and tensors does not produce symmetry operators for the Klein-Gordon operator.

Lentiviral vectors in cancer immunotherapy.

PubMed

Oldham, Robyn Aa; Berinstein, Elliot M; Medin, Jeffrey A

2015-01-01

Basic science advances in cancer immunotherapy have resulted in various treatments that have recently shown success in the clinic. Many of these therapies require the insertion of genes into cells to directly kill them or to redirect the host's cells to induce potent immune responses. Other analogous therapies work by modifying effector cells for improved targeting and enhanced killing of tumor cells. Initial studies done using γ-retroviruses were promising, but safety concerns centered on the potential for insertional mutagenesis have highlighted the desire to develop other options for gene delivery. Lentiviral vectors (LVs) have been identified as potentially more effective and safer alternative delivery vehicles. LVs are now in use in clinical trials for many different types of inherited and acquired disorders, including cancer. This review will discuss current knowledge of LVs and the applications of this viral vector-based delivery vehicle to cancer immunotherapy.

The natural dietary genistein boosts bacteriophage-mediated cancer cell killing by improving phage-targeted tumor cell transduction.

PubMed

Tsafa, Effrosyni; Al-Bahrani, Mariam; Bentayebi, Kaoutar; Przystal, Justyna; Suwan, Keittisak; Hajitou, Amin

2016-08-09

Gene therapy has long been regarded as a promising treatment for cancer. However, cancer gene therapy is still facing the challenge of targeting gene delivery vectors specifically to tumors when administered via clinically acceptable non-invasive systemic routes (i.e. intravenous). The bacteria virus, bacteriophage (phage), represents a new generation of promising vectors in systemic gene delivery since their targeting can be achieved through phage capsid display ligands, which enable them to home to specific tumor receptors without the need to ablate any native eukaryotic tropism. We have previously reported a tumor specific bacteriophage vector named adeno-associated virus/phage, or AAVP, in which gene expression is under a recombinant human rAAV2 virus genome targeted to tumors via a ligand-directed phage capsid. However, cancer gene therapy with this tumor-targeted vector achieved variable outcomes ranging from tumor regression to no effect in both experimental and natural preclinical models. Herein, we hypothesized that combining the natural dietary genistein, with proven anticancer activity, would improve bacteriophage anticancer safe therapy. We show that combination treatment with genistein and AAVP increased targeted cancer cell killing by AAVP carrying the gene for Herpes simplex virus thymidine kinase (HSVtk) in 2D tissue cultures and 3D tumor spheroids. We found this increased tumor cell killing was associated with enhanced AAVP-mediated gene expression. Next, we established that genistein protects AAVP against proteasome degradation and enhances vector genome accumulation in the nucleus. Combination of genistein and phage-guided virotherapy is a safe and promising strategy that should be considered in anticancer therapy with AAVP.

LETTER TO THE EDITOR: Anti-self-dual Riemannian metrics without Killing vectors: can they be realized on K3?

NASA Astrophysics Data System (ADS)

Malykh, A. A.; Nutku, Y.; Sheftel, M. B.

2003-11-01

Explicit Riemannian metrics with Euclidean signature and anti-self-dual curvature that do not admit any Killing vectors are presented. The metric and the Riemann curvature scalars are homogeneous functions of degree zero in a single real potential and its derivatives. The solution for the potential is a sum of exponential functions which suggests that for the choice of a suitable domain of coordinates and parameters it can be the metric on a compact manifold. Then, by the theorem of Hitchin, it could be a class of metrics on K3, or on surfaces whose universal covering is K3.

Electron in higher-dimensional weakly charged rotating black hole spacetimes

NASA Astrophysics Data System (ADS)

Cariglia, Marco; Frolov, Valeri P.; Krtouš, Pavel; Kubizňák, David

2013-03-01

We demonstrate separability of the Dirac equation in weakly charged rotating black hole spacetimes in all dimensions. The electromagnetic field of the black hole is described by a test field approximation, with the vector potential proportional to the primary Killing vector field. It is shown that the demonstrated separability can be intrinsically characterized by the existence of a complete set of mutually commuting first-order symmetry operators generated from the principal Killing-Yano tensor. The presented results generalize the results on integrability of charged particle motion and separability of charged scalar field studied in V. P. Frolov and P. Krtous [Phys. Rev. D 83, 024016 (2011)].

A 1-D Simulation Analysis of the Development and Maintenance of the 2001 Red Tide of the Ichthyotoxic Dinoflagellate Karenia brevis on the West Florida Shelf

DTIC Science & Technology

2012-04-26

subsequent fish kills supplied additional organic nutrients for utilization by these opportunistic toxic algae. Both nutrient vectors represented organic non...ichthyotoxic levels, rapid decay of subsequent fish kills supplied additional organic nutrients for utilization by these opportunistic toxic algae. Both...HABSIM model (Fig. 2) a positive feedback of the recycled organic nutrients (DON and DOP) from decaying fish , killed by K. brevis. Note that dissolved

A Type D Non-Vacuum Spacetime with Causality Violating Curves, and Its Physical Interpretation

NASA Astrophysics Data System (ADS)

Ahmed, Faizuddin

2017-12-01

We present a topologically trivial, non-vacuum solution of the Einstein’s field equations in four dimensions, which is regular everywhere. The metric admits circular closed timelike curves, which appear beyond the null curve, and these timelike curves are linearly stable under linear perturbations. Additionally, the spacetime admits null geodesics curve, which are not closed, and the metric is of type D in the Petrov classification scheme. The stress-energy tensor anisotropic fluid satisfy the different energy conditions and a generalization of Equation-of-State parameter of perfect fluid p=ω ρ . The metric admits a twisting, shearfree, nonexapnding timelike geodesic congruence. Finally, the physical interpretation of this solution, based on the study of the equation of the geodesics deviation, will be presented.

NOTE: Circular symmetry in topologically massive gravity

NASA Astrophysics Data System (ADS)

Deser, S.; Franklin, J.

2010-05-01

We re-derive, compactly, a topologically massive gravity (TMG) decoupling theorem: source-free TMG separates into its Einstein and Cotton sectors for spaces with a hypersurface-orthogonal Killing vector, here concretely for circular symmetry. We then generalize the theorem to include matter; surprisingly, the single Killing symmetry also forces conformal invariance, requiring the sources to be null.

A simple test for spacetime symmetry

NASA Astrophysics Data System (ADS)

Houri, Tsuyoshi; Yasui, Yukinori

2015-03-01

This paper presents a simple method for investigating spacetime symmetry for a given metric. The method makes use of the curvature conditions that are obtained from the Killing equations. We use the solutions of the curvature conditions to compute an upper bound on the number of Killing vector fields, as well as Killing-Yano (KY) tensors and closed conformal KY tensors. We also use them in the integration of the Killing equations. By means of the method, we thoroughly investigate KY symmetry of type D vacuum solutions such as the Kerr metric in four dimensions. The method is also applied to a large variety of physical metrics in four and five dimensions.

Ladder operators for the Klein-Gordon equation with a scalar curvature term

NASA Astrophysics Data System (ADS)

Mück, Wolfgang

2018-01-01

Recently, Cardoso, Houri and Kimura constructed generalized ladder operators for massive Klein-Gordon scalar fields in space-times with conformal symmetry. Their construction requires a closed conformal Killing vector, which is also an eigenvector of the Ricci tensor. Here, a similar procedure is used to construct generalized ladder operators for the Klein-Gordon equation with a scalar curvature term. It is proven that a ladder operator requires the existence of a conformal Killing vector, which must satisfy an additional property. This property is necessary and sufficient for the construction of a ladder operator. For maximally symmetric space-times, the results are equivalent to those of Cardoso, Houri and Kimura.

Riemannian and Lorentzian flow-cut theorems

NASA Astrophysics Data System (ADS)

Headrick, Matthew; Hubeny, Veronika E.

2018-05-01

We prove several geometric theorems using tools from the theory of convex optimization. In the Riemannian setting, we prove the max flow-min cut (MFMC) theorem for boundary regions, applied recently to develop a ‘bit-thread’ interpretation of holographic entanglement entropies. We also prove various properties of the max flow and min cut, including respective nesting properties. In the Lorentzian setting, we prove the analogous MFMC theorem, which states that the volume of a maximal slice equals the flux of a minimal flow, where a flow is defined as a divergenceless timelike vector field with norm at least 1. This theorem includes as a special case a continuum version of Dilworth’s theorem from the theory of partially ordered sets. We include a brief review of the necessary tools from the theory of convex optimization, in particular Lagrangian duality and convex relaxation.

Euclidean supergravity

NASA Astrophysics Data System (ADS)

de Wit, Bernard; Reys, Valentin

2017-12-01

Supergravity with eight supercharges in a four-dimensional Euclidean space is constructed at the full non-linear level by performing an off-shell time-like reduction of five-dimensional supergravity. The resulting four-dimensional theory is realized off-shell with the Weyl, vector and tensor supermultiplets and a corresponding multiplet calculus. Hypermultiplets are included as well, but they are themselves only realized with on-shell supersymmetry. We also briefly discuss the non-linear supermultiplet. The off-shell reduction leads to a full understanding of the Euclidean theory. A complete multiplet calculus is presented along the lines of the Minkowskian theory. Unlike in Minkowski space, chiral and anti-chiral multiplets are real and supersymmetric actions are generally unbounded from below. Precisely as in the Minkowski case, where one has different formulations of Poincaré supergravity upon introducing different compensating supermultiplets, one can also obtain different versions of Euclidean supergravity.

The natural dietary genistein boosts bacteriophage-mediated cancer cell killing by improving phage-targeted tumor cell transduction

PubMed Central

Tsafa, Effrosyni; Al-Bahrani, Mariam; Bentayebi, Kaoutar; Przystal, Justyna; Suwan, Keittisak; Hajitou, Amin

2016-01-01

Gene therapy has long been regarded as a promising treatment for cancer. However, cancer gene therapy is still facing the challenge of targeting gene delivery vectors specifically to tumors when administered via clinically acceptable non-invasive systemic routes (i.e. intravenous). The bacteria virus, bacteriophage (phage), represents a new generation of promising vectors in systemic gene delivery since their targeting can be achieved through phage capsid display ligands, which enable them to home to specific tumor receptors without the need to ablate any native eukaryotic tropism. We have previously reported a tumor specific bacteriophage vector named adeno-associated virus/phage, or AAVP, in which gene expression is under a recombinant human rAAV2 virus genome targeted to tumors via a ligand-directed phage capsid. However, cancer gene therapy with this tumor-targeted vector achieved variable outcomes ranging from tumor regression to no effect in both experimental and natural preclinical models. Herein, we hypothesized that combining the natural dietary genistein, with proven anticancer activity, would improve bacteriophage anticancer safe therapy. We show that combination treatment with genistein and AAVP increased targeted cancer cell killing by AAVP carrying the gene for Herpes simplex virus thymidine kinase (HSVtk) in 2D tissue cultures and 3D tumor spheroids. We found this increased tumor cell killing was associated with enhanced AAVP-mediated gene expression. Next, we established that genistein protects AAVP against proteasome degradation and enhances vector genome accumulation in the nucleus. Combination of genistein and phage-guided virotherapy is a safe and promising strategy that should be considered in anticancer therapy with AAVP. PMID:27437775

Ergoregions in magnetized black hole spacetimes

NASA Astrophysics Data System (ADS)

Gibbons, G. W.; Mujtaba, A. H.; Pope, C. N.

2013-06-01

The spacetimes obtained by Ernst’s procedure for appending an external magnetic field B to a seed Kerr-Newman black hole are commonly believed to be asymptotic to the static Melvin metric. We show that this is not in general true. Unless the electric charge of the black hole satisfies Q= jB(1+{\\textstyle {\\frac{\\scriptstyle 1}{\\scriptstyle 4} } } j^2 B^4), where j is the angular momentum of the original seed solution, an ergoregion extends all the way from the black hole horizon to infinity. We find that if the condition on the electric charge is satisfied then the metric is asymptotic to the static Melvin metric, and the electromagnetic field carries not only magnetic, but also electric, flux along the axis. We give a self-contained account of the solution-generating procedure, including explicit formulae for the metric and the vector potential. In the case when Q= jB(1+{\\textstyle {\\frac{\\scriptstyle 1}{\\scriptstyle 4} } } j^2 B^4), we show that there is an arbitrariness in the choice of asymptotically timelike Killing field K_\\Omega = {\\partial }/{\\partial }t+ \\Omega \\, {\\partial }/{\\partial }\\phi, because there is no canonical choice of Ω. For one choice, Ω = Ωs, the metric is asymptotically static, and there is an ergoregion confined to the neighbourhood of the horizon. On the other hand, by choosing Ω = ΩH, so that K_{\\Omega _H} is co-rotating with the horizon, then for sufficiently large B numerical studies indicate there is no ergoregion at all. For smaller values, in a range B- < B < B+, there is a toroidal ergoregion outside and disjoint from the horizon. If B ⩽ B- this ergoregion expands all the way to infinity in a cylindrical region near to the rotation axis. For black holes whose size is small compared to the Melvin radius 2/B, and neglecting back-reaction of the electromagnetic field, we recover Wald’s result that it is energetically favourable for the hole to acquire a charge 2jB.

In vivo marking of spontaneous or vaccine-induced fibrosarcomas in the domestic house cat, using an adenoviral vector containing a bifunctional fusion protein, GAL-TEK.

PubMed

Marini, F C; Cannon, J P; Belmont, J W; Shillitoe, E J; Lapeyre, J N

1995-09-01

We evaluated the ability of a replication-deficient, recombinant adenoviral vector to transfer the bifunctional gene GAL-TEK, which expresses a marking/therapeutic gene product, to naturally occurring cat fibrosarcomas in situ. GAL-TEK contains an in-frame fusion of the bacterial LacZ gene for histochemical marking of tumors with beta-galactosidase (beta-Gal) and the HSV tk gene for enzyme-prodrug activation of the prodrug ganciclovir (GCV) to induce selective tumor cell killing. GAL-TEK bifunctional marking and cell killing activities were tested in vitro after adenoviral vector infection of HT1080 human fibrosarcoma cells. The tk activity of GAL-TEK is shown to be almost as potent as HSV tk to catalyze conversion of GCV to GCV nucleotides and promote selective cell killing. Using 8 cats with recurring 2.5-cm2 fibrosarcomas that either arose spontaneously or were induced by vaccine, we determined experimentally the administration routes and times required for optimum GAL-TEK gene transfer by beta-Gal histological staining and reverse transcriptase polymerase chain reaction to the multiple compartments of the growing fibrosarcomas consonant with minimizing collateral infection of neighboring tissues and other unwanted side effects.

Probing the effects of Lorentz-symmetry violating Chern-Simons and Ricci-Cotton terms in higher derivative gravity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pereira-Dias, B.; Hernaski, C. A.; Helayeel-Neto, J. A.

The combined effects of the Lorentz-symmetry violating Chern-Simons and Ricci-Cotton actions are investigated for the Einstein-Hilbert gravity in the second-order formalism modified by higher derivative terms, and their consequences on the spectrum of excitations are analyzed. We follow the lines of previous works and build up an orthonormal basis of projector-like operators for the degrees of freedom, rather than for the spin modes of the fields. With this new basis, the attainment of the propagators is remarkably simplified and the identification of the physical and unphysical modes becomes more immediate. Our conclusion is that the only tachyon- and ghost-free modelmore » is the Einstein-Hilbert action added up by the Chern-Simons term with a timelike vector of the type v{sup {mu}=}({mu},0-vector). Spectral consistency imposes that the Ricci-Cotton term must be switched off. We then infer that gravity with Lorentz-symmetry violation imposes a drastically different constraint on the background if compared to ordinary gauge theories whenever conditions for the suppression of tachyons and ghosts are imposed.« less

Replicating the benefits of Deutschian closed timelike curves without breaking causality

NASA Astrophysics Data System (ADS)

Yuan, Xiao; Assad, Syed M.; Thompson, Jayne; Haw, Jing Yan; Vedral, Vlatko; Ralph, Timothy C.; Lam, Ping Koy; Weedbrook, Christian; Gu, Mile

2015-11-01

In general relativity, closed timelike curves can break causality with remarkable and unsettling consequences. At the classical level, they induce causal paradoxes disturbing enough to motivate conjectures that explicitly prevent their existence. At the quantum level such problems can be resolved through the Deutschian formalism, however this induces radical benefits—from cloning unknown quantum states to solving problems intractable to quantum computers. Instinctively, one expects these benefits to vanish if causality is respected. Here we show that in harnessing entanglement, we can efficiently solve NP-complete problems and clone arbitrary quantum states—even when all time-travelling systems are completely isolated from the past. Thus, the many defining benefits of Deutschian closed timelike curves can still be harnessed, even when causality is preserved. Our results unveil a subtle interplay between entanglement and general relativity, and significantly improve the potential of probing the radical effects that may exist at the interface between relativity and quantum theory.

Vectors, viscin, and Viscaceae: mistletoes as parasites, mutualists, and resources.

Treesearch

Juliann E. Aukema

2003-01-01

Mistletoes are aerial, hemiparasitic plants found on trees throughout the world. They have unique ecological arrangements with the host plants they parasitize and the birds that disperse their seeds. Similar in many respects to vector-borne macroparasites, mistletoes are often detrimental to their hosts, and can even kill them. Coevolution has led to resistance...

Oral, Slow-Release Ivermectin: Biting Back at Malaria Vectors.

PubMed

Chaccour, Carlos J; Rabinovich, N Regina

2017-03-01

Bellinger and colleagues offer an elegant twist for a promising new tool against malaria. This formulation is designed to release ivermectin, a mosquito-killing drug for 10 days after a single oral dose. This could reduce the vector population and serve as a complementary tool for malaria elimination. Copyright © 2016 Elsevier Ltd. All rights reserved.

Is California bay laurel a suitable host for the non-native redbay ambrosia beetle, vector of laurel wilt disease?

USDA-ARS?s Scientific Manuscript database

Laurel wilt is a deadly vascular disease of trees in the Lauraceae that kills healthy redbay (Persea borbonia), sassafras (Sassafras albidum), and other related hosts. The fungal pathogen (Raffaelea lauricola) and it vector, the redbay ambrosia beetle (Xyleborus glabratus) are native to Asia and ha...

Radiation-like scalar field and gauge fields in cosmology for a theory with dynamical time

NASA Astrophysics Data System (ADS)

Benisty, David; Guendelman, E. I.

2016-09-01

Cosmological solutions with a scalar field behaving as radiation are obtained, in the context of gravitational theory with dynamical time. The solution requires the spacial curvature of the universe k, to be zero, unlike the standard radiation solutions, which do not impose any constraint on the spatial curvature of the universe. This is because only such k = 0 radiation solutions pose a homothetic Killing vector. This kind of theory can be used to generalize electromagnetism and other gauge theories, in curved spacetime, and there are no deviations from standard gauge field equation (like Maxwell equations) in the case there exist a conformal Killing vector. But there could be departures from Maxwell and Yang-Mills equations, for more general spacetimes.

Intertwined Hamiltonians in two-dimensional curved spaces

NASA Astrophysics Data System (ADS)

Aghababaei Samani, Keivan; Zarei, Mina

2005-04-01

The problem of intertwined Hamiltonians in two-dimensional curved spaces is investigated. Explicit results are obtained for Euclidean plane, Minkowski plane, Poincaré half plane (AdS2), de Sitter plane (dS2), sphere, and torus. It is shown that the intertwining operator is related to the Killing vector fields and the isometry group of corresponding space. It is shown that the intertwined potentials are closely connected to the integral curves of the Killing vector fields. Two problems are considered as applications of the formalism presented in the paper. The first one is the problem of Hamiltonians with equispaced energy levels and the second one is the problem of Hamiltonians whose spectrum is like the spectrum of a free particle.

Poly-functional and long-lasting anticancer immune response elicited by a safe attenuated Pseudomonas aeruginosa vector for antigens delivery

PubMed Central

Chauchet, Xavier; Hannani, Dalil; Djebali, Sophia; Laurin, David; Polack, Benoit; Marvel, Jacqueline; Buffat, Laurent; Toussaint, Bertrand; Le Gouëllec, Audrey

2016-01-01

Live-attenuated bacterial vectors for antigens delivery have aroused growing interest in the field of cancer immunotherapy. Their potency to stimulate innate immunity and to promote intracellular antigen delivery into antigen-presenting cells could be exploited to elicit a strong and specific cellular immune response against tumor cells. We previously described genetically-modified and attenuated Pseudomonas aeruginosa vectors able to deliver in vivo protein antigens into antigen-presenting cells, through Type 3 secretion system of the bacteria. Using this approach, we managed to protect immunized mice against aggressive B16 melanoma development in both a prophylactic and therapeutic setting. In this study, we further investigated the antigen-specific CD8+ T cell response, in terms of phenotypic and functional aspects, obtained after immunizations with a killed but metabolically active P. aeruginosa attenuated vector. We demonstrated that P. aeruginosa vaccine induces a highly functional pool of antigen-specific CD8+ T cell able to infiltrate the tumor. Furthermore, multiple immunizations allowed the development of a long-lasting immune response, represented by a pool of predominantly effector memory cells which protected mice against late tumor challenge. Overall, killed but metabolically active P. aeruginosa vector is a safe and promising approach for active and specific antitumor immunotherapy. PMID:28035332

Upper limits of the proton magnetic form factor in the time-like region from p¯p--> e+e- at the CERN-ISR

NASA Astrophysics Data System (ADS)

Baglin, C.; Baird, S.; Bassompierre, G.; Borreani, G.; Brient, J. C.; Broll, C.; Brom, J. M.; Bugge, L.; Buran, T.; Burq, J. P.; Bussière, A.; Buzzo, A.; Cester, R.; Chemarin, M.; Chevallier, M.; Escoubes, B.; Fay, J.; Ferroni, S.; Gracco, V.; Guillaud, J. P.; Khan-Aronsen, E.; Kirsebom, K.; Ille, B.; Lambert, M.; Leistam, L.; Lundby, A.; Macri, M.; Marchetto, F.; Mattera, L.; Menichetti, E.; Mouellic, B.; Pastrone, N.; Petrillo, L.; Pia, M. G.; Poulet, M.; Pozzo, A.; Rinaudo, G.; Santroni, A.; Severi, M.; Skjevling, G.; Stapnes, S.; Stugu, B.; Tomasini, F.; Valbusa, U.

1985-11-01

From the measurement of e+e- pairs from the reaction p¯p-->e+e- at the CERN-ISR, using an antiproton beam and a hydrogen jet target, we derived upper limits for the proton magnetic form factor in the time-like region at Q2⋍8.9(GeV/c)2 and Q2⋍12.5(GeV/c)2.

Universal properties from a local geometric structure of a Killing horizon

NASA Astrophysics Data System (ADS)

Koga, Jun-ichirou

2007-06-01

We consider universal properties that arise from a local geometric structure of a Killing horizon, and analyse whether such universal properties give rise to degeneracy of classical configurations. We first introduce a non-perturbative definition of such a local geometric structure, which we call an asymptotic Killing horizon. It is then shown that infinitely many asymptotic Killing horizons reside on a common null hypersurface, once there exists one asymptotic Killing horizon, which is thus considered as degeneracy. In order to see how this degeneracy is physically meaningful, we analyse also the acceleration of the orbits of the vector that generates an asymptotic Killing horizon. It is shown that there exists the diff(S1) or diff(R1) sub-algebra on an asymptotic Killing horizon universally, which is picked out naturally, based on the behaviour of the acceleration. We argue that the discrepancy between string theory and the Euclidean approach in the entropy of an extreme black hole may be resolved, if the microscopic states responsible for black hole thermodynamics are connected with asymptotic Killing horizons.

Nucleon form factors in dispersively improved chiral effective field theory: Scalar form factor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alarcon Soriano, Jose Manuel; Weiss, Christian

We propose a method for calculating the nucleon form factors (FFs) ofmore » $G$-parity-even operators by combining Chiral Effective Field Theory ($$\\chi$$EFT) and dispersion analysis. The FFs are expressed as dispersive integrals over the two-pion cut at $$t > 4 M_\\pi^2$$. The spectral functions are obtained from the elastic unitarity condition and expressed as products of the complex $$\\pi\\pi \\rightarrow N\\bar N$$ partial-wave amplitudes and the timelike pion FF. $$\\chi$$EFT is used to calculate the ratio of the partial-wave amplitudes and the pion FF, which is real and free of $$\\pi\\pi$$ rescattering in the $t$-channel ($N/D$ method). The rescattering effects are then incorporated by multiplying with the squared modulus of the empirical pion FF. The procedure results in a marked improvement compared to conventional $$\\chi$$EFT calculations of the spectral functions. We apply the method to the nucleon scalar FF and compute the scalar spectral function, the scalar radius, the $t$-dependent FF, and the Cheng-Dashen discrepancy. Higher-order chiral corrections are estimated through the $$\\pi N$$ low-energy constants. Results are in excellent agreement with dispersion-theoretical calculations. We elaborate several other interesting aspects of our method. The results show proper scaling behavior in the large-$$N_c$$ limit of QCD because the $$\\chi$$EFT includes $N$ and $$\\Delta$$ intermediate states. The squared modulus of the timelike pion FF required by our method can be extracted from Lattice QCD calculations of vacuum correlation functions of the operator at large Euclidean distances. Our method can be applied to the nucleon FFs of other operators of interest, such as the isovector-vector current, the energy-momentum tensor, and twist-2 QCD operators (moments of generalized parton distributions).« less

Stability and Instability of the Sub-extremal Reissner-Nordström Black Hole Interior for the Einstein-Maxwell-Klein-Gordon Equations in Spherical Symmetry

NASA Astrophysics Data System (ADS)

Van de Moortel, Maxime

2018-05-01

We show non-linear stability and instability results in spherical symmetry for the interior of a charged black hole—approaching a sub-extremal Reissner-Nordström background fast enough—in presence of a massive and charged scalar field, motivated by the strong cosmic censorship conjecture in that setting: 1. Stability We prove that spherically symmetric characteristic initial data to the Einstein-Maxwell-Klein-Gordon equations approaching a Reissner-Nordström background with a sufficiently decaying polynomial decay rate on the event horizon gives rise to a space-time possessing a Cauchy horizon in a neighbourhood of time-like infinity. Moreover, if the decay is even stronger, we prove that the space-time metric admits a continuous extension to the Cauchy horizon. This generalizes the celebrated stability result of Dafermos for Einstein-Maxwell-real-scalar-field in spherical symmetry. 2. Instability We prove that for the class of space-times considered in the stability part, whose scalar field in addition obeys a polynomial averaged- L 2 (consistent) lower bound on the event horizon, the scalar field obeys an integrated lower bound transversally to the Cauchy horizon. As a consequence we prove that the non-degenerate energy is infinite on any null surface crossing the Cauchy horizon and the curvature of a geodesic vector field blows up at the Cauchy horizon near time-like infinity. This generalizes an instability result due to Luk and Oh for Einstein-Maxwell-real-scalar-field in spherical symmetry. This instability of the black hole interior can also be viewed as a step towards the resolution of the C 2 strong cosmic censorship conjecture for one-ended asymptotically flat initial data.

Nucleon form factors in dispersively improved chiral effective field theory: Scalar form factor

DOE PAGES

Alarcon Soriano, Jose Manuel; Weiss, Christian

2017-11-20

We propose a method for calculating the nucleon form factors (FFs) ofmore » $G$-parity-even operators by combining Chiral Effective Field Theory ($$\\chi$$EFT) and dispersion analysis. The FFs are expressed as dispersive integrals over the two-pion cut at $$t > 4 M_\\pi^2$$. The spectral functions are obtained from the elastic unitarity condition and expressed as products of the complex $$\\pi\\pi \\rightarrow N\\bar N$$ partial-wave amplitudes and the timelike pion FF. $$\\chi$$EFT is used to calculate the ratio of the partial-wave amplitudes and the pion FF, which is real and free of $$\\pi\\pi$$ rescattering in the $t$-channel ($N/D$ method). The rescattering effects are then incorporated by multiplying with the squared modulus of the empirical pion FF. The procedure results in a marked improvement compared to conventional $$\\chi$$EFT calculations of the spectral functions. We apply the method to the nucleon scalar FF and compute the scalar spectral function, the scalar radius, the $t$-dependent FF, and the Cheng-Dashen discrepancy. Higher-order chiral corrections are estimated through the $$\\pi N$$ low-energy constants. Results are in excellent agreement with dispersion-theoretical calculations. We elaborate several other interesting aspects of our method. The results show proper scaling behavior in the large-$$N_c$$ limit of QCD because the $$\\chi$$EFT includes $N$ and $$\\Delta$$ intermediate states. The squared modulus of the timelike pion FF required by our method can be extracted from Lattice QCD calculations of vacuum correlation functions of the operator at large Euclidean distances. Our method can be applied to the nucleon FFs of other operators of interest, such as the isovector-vector current, the energy-momentum tensor, and twist-2 QCD operators (moments of generalized parton distributions).« less

Hawking radiation and propagation of massive charged scalar field on a three-dimensional Gödel black hole

NASA Astrophysics Data System (ADS)

González, P. A.; Övgün, Ali; Saavedra, Joel; Vásquez, Yerko

2018-06-01

In this paper we consider the three-dimensional Gödel black hole as a background and we study the vector particle tunneling from this background in order to obtain the Hawking temperature. Then, we study the propagation of a massive charged scalar field and we find the quasinormal modes analytically, which turns out be unstable as a consequence of the existence of closed time-like curves. Also, we consider the flux at the horizon and at infinity, and we compute the reflection and transmission coefficients as well as the absorption cross section. Mainly, we show that massive charged scalar waves can be superradiantly amplified by the three-dimensional Gödel black hole and that the coefficients have an oscillatory behavior. Moreover, the absorption cross section is null at the high frequency limit and for certain values of the frequency.

Three-body decays B →ϕ (ρ )K γ in perturbative QCD approach

NASA Astrophysics Data System (ADS)

Wang, Chao; Liu, Jing-Bin; Li, Hsiang-nan; Lü, Cai-Dian

2018-02-01

We study the three-body radiative decays B →ϕ (ρ )K γ induced by a flavor-changing neutral current in the perturbative QCD approach. Pseudoscalar-vector (P V ) distribution amplitudes (DAs) are introduced for the final-state ϕ K (ρ K ) pair to capture important infrared dynamics in the region with a small P V -pair invariant mass. The dependence of these P V DAs on the parton momentum fraction is parametrized in terms of the Gegenbauer polynomials, and the dependence on the meson momentum fraction is derived through their normalizations to timelike P V form factors. In addition to the dominant electromagnetic penguin, the subleading chromomagnetic penguin, quark-loop and annihilation diagrams are also calculated. After determining the P V DAs from relevant branching-ratio data, the direct C P asymmetries and decay spectra in the P V -pair invariant mass are predicted for each B →ϕ (ρ )K γ mode.

Curved manifolds with conserved Runge-Lenz vectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ngome, J.-P.

2009-12-15

van Holten's algorithm is used to construct Runge-Lenz-type conserved quantities, induced by Killing tensors, on curved manifolds. For the generalized Taub-Newman-Unti-Tamburino metric, the most general external potential such that the combined system admits a conserved Runge-Lenz-type vector is found. In the multicenter case, the subclass of two-center metric exhibits a conserved Runge-Lenz-type scalar.

Curved manifolds with conserved Runge-Lenz vectors

NASA Astrophysics Data System (ADS)

Ngome, J.-P.

2009-12-01

van Holten's algorithm is used to construct Runge-Lenz-type conserved quantities, induced by Killing tensors, on curved manifolds. For the generalized Taub-Newman-Unti-Tamburino metric, the most general external potential such that the combined system admits a conserved Runge-Lenz-type vector is found. In the multicenter case, the subclass of two-center metric exhibits a conserved Runge-Lenz-type scalar.

Towards timelike singularity via AdS dual

NASA Astrophysics Data System (ADS)

Bhowmick, Samrat; Chatterjee, Soumyabrata

2017-07-01

It is well known that Kasner geometry with spacelike singularity can be extended to bulk AdS-like geometry, furthermore, one can study field theory on this Kasner space via its gravity dual. In this paper, we show that there exists a Kasner-like geometry with timelike singularity for which one can construct a dual gravity description. We then study various extremal surfaces including spacelike geodesics in the dual gravity description. Finally, we compute correlators of highly massive operators in the boundary field theory with a geodesic approximation.

Optimal time travel in the Gödel universe

NASA Astrophysics Data System (ADS)

Natário, José

2012-04-01

Using the theory of optimal rocket trajectories in general relativity, recently developed in Henriques and Natário (2011), we present a candidate for the minimum total integrated acceleration closed timelike curve in the Gödel universe, and give evidence for its minimality. The total integrated acceleration of this curve is lower than Malament's conjectured value (Malament 1984), as was already implicit in the work of Manchak (Gen. Relativ. Gravit. 51-60, 2011); however, Malament's conjecture does seem to hold for periodic closed timelike curves.

NNLO splitting and coefficient functions with time-like kinematics

NASA Astrophysics Data System (ADS)

Mitov, A.; Moch, S.; Vogt, A.

2006-10-01

We discuss recent results on the three-loop (next-to-next-to-leading order, NNLO) time-like splitting functions of QCD and the two-loop (NNLO) coefficient functions in one-particle inclusive e+e--annihilation. These results form the basis for extracting fragmentation functions for light and heavy flavors with NNLO accuracy that will be needed at the LHC and ILC. The two-loop calculations have been performed in Mellin space based on a new method, the main features of which we also describe briefly.

Straight spinning cosmic strings in Brans-Dicke gravity

NASA Astrophysics Data System (ADS)

Dos Santos, S. Mittmann; da Silva, J. M. Hoff; Cindra, J. L.

2018-03-01

An exact solution of straight spinning cosmic strings in Brans-Dicke theory of gravitation is presented. The possibility of the existence of closed time-like curves around these cosmic strings is analyzed. Furthermore, the stability about the formation of the topological defect discussed here is checked. It is shown that the existence of a suitable choice for the integration constants in which closed time-like curves are not allowed. We also study the (im)possibility of using the obtained spacetime in the rotational curves problem.

Limit of Kerr-de Sitter spacetime with infinite angular-momentum parameter a

NASA Astrophysics Data System (ADS)

Mars, Marc; Paetz, Tim-Torben; Senovilla, José M. M.

2018-01-01

We consider the limit a →∞ of the Kerr-de Sitter spacetime. The spacetime is a Petrov type-D solution of the vacuum Einstein field equations with a positive cosmological constant Λ , vanishing Mars-Simon tensor and conformally flat ℐ . It possesses an Abelian 2-dimensional group of symmetries whose orbits are spacelike or timelike in different regions, and it includes, as a particular case, de Sitter spacetime. The global structure of the solution is analyzed in detail, with particular attention to its Killing horizons: they are foliated by noncompact marginally trapped surfaces of finite area, and one of them "touches" the curvature singularity, which resembles a null 2-dimensional surface. Outside the region between these horizons there exist trapped surfaces that again are noncompact. The solution contains, apart from Λ , a unique free parameter which can be related to the angular momentum of the nonsingular horizon in a precise way. A maximal extension of the (axis of the) spacetime is explicitly built. We also analyze the structure of ℐ , whose topology is R3.

Negative branes, supergroups and the signature of spacetime

NASA Astrophysics Data System (ADS)

Dijkgraaf, Robbert; Heidenreich, Ben; Jefferson, Patrick; Vafa, Cumrun

2018-02-01

We study the realization of supergroup gauge theories using negative branes in string theory. We show that negative branes are intimately connected with the possibility of timelike compactification and exotic spacetime signatures previously studied by Hull. Isolated negative branes dynamically generate a change in spacetime signature near their worldvolumes, and are related by string dualities to a smooth M-theory geometry with closed timelike curves. Using negative D3-branes, we show that SU(0| N) supergroup theories are holographically dual to an exotic variant of type IIB string theory on {dS}_{3,2}× {\\overline{S}}^5 , for which the emergent dimensions are timelike. Using branes, mirror symmetry and Nekrasov's instanton calculus, all of which agree, we derive the Seiberg-Witten curve for N=2 SU( N | M ) gauge theories. Together with our exploration of holography and string dualities for negative branes, this suggests that supergroup gauge theories may be non-perturbatively well-defined objects, though several puzzles remain.

Simplified Models of Vector Control Impact upon Malaria Transmission by Zoophagic Mosquitoes

PubMed Central

Kiware, Samson S.; Chitnis, Nakul; Moore, Sarah J.; Devine, Gregor J.; Majambere, Silas; Merrill, Stephen; Killeen, Gerry F.

2012-01-01

Background High coverage of personal protection measures that kill mosquitoes dramatically reduce malaria transmission where vector populations depend upon human blood. However, most primary malaria vectors outside of sub-Saharan Africa can be classified as “very zoophagic,” meaning they feed occasionally (<10% of blood meals) upon humans, so personal protection interventions have negligible impact upon their survival. Methods and Findings We extended a published malaria transmission model to examine the relationship between transmission, control, and the baseline proportion of bloodmeals obtained from humans (human blood index). The lower limit of the human blood index enables derivation of simplified models for zoophagic vectors that (1) Rely on only three field-measurable parameters. (2) Predict immediate and delayed (with and without assuming reduced human infectivity, respectively) impacts of personal protection measures upon transmission. (3) Illustrate how appreciable indirect communal-level protection for non-users can be accrued through direct personal protection of users. (4) Suggest the coverage and efficacy thresholds required to attain epidemiological impact. The findings suggest that immediate, indirect, community-wide protection of users and non-users alike may linearly relate to the efficacy of a user’s direct personal protection, regardless of whether that is achieved by killing or repelling mosquitoes. High protective coverage and efficacy (≥80%) are important to achieve epidemiologically meaningful impact. Non-users are indirectly protected because the two most common species of human malaria are strict anthroponoses. Therefore, the small proportion of mosquitoes that are killed or diverted while attacking humans can represent a large proportion of those actually transmitting malaria. Conclusions Simplified models of malaria transmission by very zoophagic vectors may be used by control practitioners to predict intervention impact interventions using three field-measurable parameters; the proportion of human exposure to mosquitoes occurring when an intervention can be practically used, its protective efficacy when used, and the proportion of people using it. PMID:22701527

Chapter 11 - Progression of Laurel Wilt Disease in Georgia: 2009–11 (Project SC-EM-08-02)

Treesearch

R. Scott Cameron; Chip Bates; James Johnson

2014-01-01

Laurel wilt disease (LWD) is caused by the fungus Raffaelea lauricola and vectored by the redbay ambrosia beetle (RAB), Xyleborus glabratus (Fraedrich and others 2008). The pathogen and vector were apparently introduced from Asia through the Port of Savannah, and the disease has spread rapidly throughout the lower coastal plains forests in Georgia, killing nearly all...

Vectorial capacity and vector control: reconsidering sensitivity to parameters for malaria elimination

PubMed Central

Brady, Oliver J.; Godfray, H. Charles J.; Tatem, Andrew J.; Gething, Peter W.; Cohen, Justin M.; McKenzie, F. Ellis; Perkins, T. Alex; Reiner, Robert C.; Tusting, Lucy S.; Sinka, Marianne E.; Moyes, Catherine L.; Eckhoff, Philip A.; Scott, Thomas W.; Lindsay, Steven W.; Hay, Simon I.; Smith, David L.

2016-01-01

Background Major gains have been made in reducing malaria transmission in many parts of the world, principally by scaling-up coverage with long-lasting insecticidal nets and indoor residual spraying. Historically, choice of vector control intervention has been largely guided by a parameter sensitivity analysis of George Macdonald's theory of vectorial capacity that suggested prioritizing methods that kill adult mosquitoes. While this advice has been highly successful for transmission suppression, there is a need to revisit these arguments as policymakers in certain areas consider which combinations of interventions are required to eliminate malaria. Methods and Results Using analytical solutions to updated equations for vectorial capacity we build on previous work to show that, while adult killing methods can be highly effective under many circumstances, other vector control methods are frequently required to fill effective coverage gaps. These can arise due to pre-existing or developing mosquito physiological and behavioral refractoriness but also due to additive changes in the relative importance of different vector species for transmission. Furthermore, the optimal combination of interventions will depend on the operational constraints and costs associated with reaching high coverage levels with each intervention. Conclusions Reaching specific policy goals, such as elimination, in defined contexts requires increasingly non-generic advice from modelling. Our results emphasize the importance of measuring baseline epidemiology, intervention coverage, vector ecology and program operational constraints in predicting expected outcomes with different combinations of interventions. PMID:26822603

No time machine construction in open 2+1 gravity with timelike total energy-momentum

NASA Astrophysics Data System (ADS)

Tiglio, Manuel H.

1998-09-01

It is shown that in (2+1)-dimensional gravity an open spacetime with timelike sources and total energy momentum cannot have a stable compactly generated Cauchy horizon. This constitutes a proof of a version of Kabat's conjecture and shows, in particular, that not only a Gott time machine cannot be formed from processes such as the decay of a single cosmic string as has been shown by Carroll et al., but that, in a precise sense, a time machine cannot be constructed at all.

Closed timelike curves produced by pairs of moving cosmic strings - Exact solutions

NASA Technical Reports Server (NTRS)

Gott, J. Richard, III

1991-01-01

Exact solutions of Einstein's field equations are presented for the general case of two moving straight cosmic strings that do not intersect. The solutions for parallel cosmic strings moving in opposite directions show closed timelike curves (CTCs) that circle the two strings as they pass, allowing observers to visit their own past. Similar results occur for nonparallel strings, and for masses in (2+1)-dimensional spacetime. For finite string loops the possibility that black-hole formation may prevent the formation of CTCs is discussed.

Higher symmetries of the Schrödinger operator in Newton-Cartan geometry

NASA Astrophysics Data System (ADS)

Gundry, James

2017-03-01

We establish several relationships between the non-relativistic conformal symmetries of Newton-Cartan geometry and the Schrödinger equation. In particular we discuss the algebra sch(d) of vector fields conformally-preserving a flat Newton-Cartan spacetime, and we prove that its curved generalisation generates the symmetry group of the covariant Schrödinger equation coupled to a Newtonian potential and generalised Coriolis force. We provide intrinsic Newton-Cartan definitions of Killing tensors and conformal Schrödinger-Killing tensors, and we discuss their respective links to conserved quantities and to the higher symmetries of the Schrödinger equation. Finally we consider the role of conformal symmetries in Newtonian twistor theory, where the infinite-dimensional algebra of holomorphic vector fields on twistor space corresponds to the symmetry algebra cnc(3) on the Newton-Cartan spacetime.

The Maxwell and Navier-Stokes equations that follow from Einstein equation in a spacetime containing a Killing vector field

NASA Astrophysics Data System (ADS)

Rodrigues, Fabio Grangeiro; Rodrigues, Waldyr Alves, Jr.; da Rocha, Roldão

2012-10-01

In this paper we are concerned to reveal that any spacetime structure , which is a model of a gravitational field in General Relativity generated by an energy-momentum tensor T - and which contains at least one nontrivial Killing vector field A - is such that the 2-form field F = dA (where A = g(A,)) satisfies a Maxwell like equation - with a well determined current that contains a term of the superconducting type- which follows directly from Einstein equation. Moreover, we show that the resulting Maxwell like equations, under an additional condition imposed to the Killing vector field, may be written as a Navier-Stokes like equation as well. As a result, we have a set consisting of Einstein, Maxwell and Navier-Stokes equations, that follows sequentially from the first one under precise mathematical conditions and once some identifications about field variables are evinced, as explained in details throughout the text. We compare and emulate our results with others on the same subject appearing in the literature. In Appendix A we fix our notation and recall some necessary material concerning the theory of differential forms, Lie derivatives and the Clifford bundle formalism used in this paper. Moreover, we comment in Appendix B on some analogies (and main differences) between our results to the ones obtained long ago by Bergmann and Kommar which are reviewed and briefly criticized.

Predicting the impact of insecticide-treated bed nets on malaria transmission: the devil is in the detail.

PubMed

Gu, Weidong; Novak, Robert J

2009-11-16

Insecticide-treated bed nets (ITNs), including long-lasting insecticidal nets (LLINs), play a primary role in global campaigns to roll back malaria in tropical Africa. Effectiveness of treated nets depends on direct impacts on individual mosquitoes including killing and excite-repellency, which vary considerably among vector species due to variations in host-seeking behaviours. While monitoring and evaluation programmes of ITNs have focuses on morbidity and all-cause mortality in humans, local entomological context receives little attention. Without knowing the dynamics of local vector species and their responses to treated nets, it is difficult to predict clinical outcomes when ITN applications are scaled up across African continent. Sound model frameworks incorporating intricate interactions between mosquitoes and treated nets are needed to develop the predictive capacity for scale-up applications of ITNs. An established agent-based model was extended to incorporate the direct outcomes, e.g. killing and avoidance, of individual mosquitoes exposing to ITNs in a hypothetical village setting with 50 houses and 90 aquatic habitats. Individual mosquitoes were tracked throughout the life cycle across the landscape. Four levels of coverage, i.e. 40, 60, 80 and 100%, were applied at the household level with treated houses having only one bed net. By using Latin hypercube sampling scheme, parameters governing killing, diverting and personal protection of net users were evaluated for their relative roles in containing mosquito populations, entomological inoculation rates (EIRs) and malaria incidence. There were substantial gaps in coverage between households and individual persons, and 100% household coverage resulted in circa 50% coverage of the population. The results show that applications of ITNs could give rise to varying impacts on population-level metrics depending on values of parameters governing interactions of mosquitoes and treated nets at the individual level. The most significant factor in determining effectiveness was killing capability of treated nets. Strong excito-repellent effect of impregnated nets might lead to higher risk exposure to non-bed net users. With variabilities of vector mosquitoes in host-seeking behaviours and the responses to treated nets, it is anticipated that scale-up applications of INTs might produce varying degrees of success dependent on local entomological and epidemiological contexts. This study highlights that increased ITN coverage led to significant reduction in risk exposure and malaria incidence only when treated nets yielded high killing effects. It is necessary to test efficacy of treated nets on local dominant vector mosquitoes, at least in laboratory, for monitoring and evaluation of ITN programmes.

Hidden symmetries of the Kerr metric and Goldstone’s theorem

NASA Astrophysics Data System (ADS)

Penna, Robert F.

2011-12-01

Perturbations of the Kerr metric admit a spectrum of massless excitations, which we interpret as Goldstone modes coming from the metric’s broken spherical symmetry. The zero-frequency mode is related to the conformal Yano-Killing tensor which encodes Carter’s constant and the Killing vectors of the spacetime. The modes are described by a conformal field theory, which becomes two-dimensional Liouville theory in the near-horizon limit. Directly counting the quantum microstates of this theory reproduces the Bekenstein-Hawking area law.

Spacetime symmetries and Kepler's third law

NASA Astrophysics Data System (ADS)

Le Tiec, Alexandre

2012-11-01

The curved spacetime geometry of a system of two point masses moving on a circular orbit has a helical symmetry. We show how Kepler’s third law for circular motion, and its generalization in post-Newtonian theory, can be recovered from a simple, covariant condition on the norm of the associated helical Killing vector field. This unusual derivation can be used to illustrate some concepts of prime importance in a general relativity course, including those of Killing field, covariance, coordinate dependence and gravitational redshift.

Vectorial capacity and vector control: reconsidering sensitivity to parameters for malaria elimination.

PubMed

Brady, Oliver J; Godfray, H Charles J; Tatem, Andrew J; Gething, Peter W; Cohen, Justin M; McKenzie, F Ellis; Perkins, T Alex; Reiner, Robert C; Tusting, Lucy S; Sinka, Marianne E; Moyes, Catherine L; Eckhoff, Philip A; Scott, Thomas W; Lindsay, Steven W; Hay, Simon I; Smith, David L

2016-02-01

Major gains have been made in reducing malaria transmission in many parts of the world, principally by scaling-up coverage with long-lasting insecticidal nets and indoor residual spraying. Historically, choice of vector control intervention has been largely guided by a parameter sensitivity analysis of George Macdonald's theory of vectorial capacity that suggested prioritizing methods that kill adult mosquitoes. While this advice has been highly successful for transmission suppression, there is a need to revisit these arguments as policymakers in certain areas consider which combinations of interventions are required to eliminate malaria. Using analytical solutions to updated equations for vectorial capacity we build on previous work to show that, while adult killing methods can be highly effective under many circumstances, other vector control methods are frequently required to fill effective coverage gaps. These can arise due to pre-existing or developing mosquito physiological and behavioral refractoriness but also due to additive changes in the relative importance of different vector species for transmission. Furthermore, the optimal combination of interventions will depend on the operational constraints and costs associated with reaching high coverage levels with each intervention. Reaching specific policy goals, such as elimination, in defined contexts requires increasingly non-generic advice from modelling. Our results emphasize the importance of measuring baseline epidemiology, intervention coverage, vector ecology and program operational constraints in predicting expected outcomes with different combinations of interventions. © The Author 2016. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene.

Increasing the Efficacy of Oncolytic Adenovirus Vectors

PubMed Central

Toth, Karoly; Wold, William S. M.

2010-01-01

Oncolytic adenovirus (Ad) vectors present a new modality to treat cancer. These vectors attack tumors via replicating in and killing cancer cells. Upon completion of the vector replication cycle, the infected tumor cell lyses and releases progeny virions that are capable of infecting neighboring tumor cells. Repeated cycles of vector replication and cell lysis can destroy the tumor. Numerous Ad vectors have been generated and tested, some of them reaching human clinical trials. In 2005, the first oncolytic Ad was approved for the treatment of head-and-neck cancer by the Chinese FDA. Oncolytic Ads have been proven to be safe, with no serious adverse effects reported even when high doses of the vector were injected intravenously. The vectors demonstrated modest anti-tumor effect when applied as a single agent; their efficacy improved when they were combined with another modality. The efficacy of oncolytic Ads can be improved using various approaches, including vector design, delivery techniques, and ancillary treatment, which will be discussed in this review. PMID:21994711

Using a new odour-baited device to explore options for luring and killing outdoor-biting malaria vectors: a report on design and field evaluation of the Mosquito Landing Box

PubMed Central

2013-01-01

Background Mosquitoes that bite people outdoors can sustain malaria transmission even where effective indoor interventions such as bednets or indoor residual spraying are already widely used. Outdoor tools may therefore complement current indoor measures and improve control. We developed and evaluated a prototype mosquito control device, the ‘Mosquito Landing Box’ (MLB), which is baited with human odours and treated with mosquitocidal agents. The findings are used to explore technical options and challenges relevant to luring and killing outdoor-biting malaria vectors in endemic settings. Methods Field experiments were conducted in Tanzania to assess if wild host-seeking mosquitoes 1) visited the MLBs, 2) stayed long or left shortly after arrival at the device, 3) visited the devices at times when humans were also outdoors, and 4) could be killed by contaminants applied on the devices. Odours suctioned from volunteer-occupied tents were also evaluated as a potential low-cost bait, by comparing baited and unbaited MLBs. Results There were significantly more Anopheles arabiensis, An. funestus, Culex and Mansonia mosquitoes visiting baited MLB than unbaited controls (P≤0.028). Increasing sampling frequency from every 120 min to 60 and 30 min led to an increase in vector catches of up to 3.6 fold (P≤0.002), indicating that many mosquitoes visited the device but left shortly afterwards. Outdoor host-seeking activity of malaria vectors peaked between 7:30 and 10:30pm, and between 4:30 and 6:00am, matching durations when locals were also outdoors. Maximum mortality of mosquitoes visiting MLBs sprayed or painted with formulations of candidate mosquitocidal agent (pirimiphos-methyl) was 51%. Odours from volunteer occupied tents attracted significantly more mosquitoes to MLBs than controls (P<0.001). Conclusion While odour-baited devices such as the MLBs clearly have potential against outdoor-biting mosquitoes in communities where LLINs are used, candidate contaminants must be those that are effective at ultra-low doses even after short contact periods, since important vector species such as An. arabiensis make only brief visits to such devices. Natural human odours suctioned from occupied dwellings could constitute affordable sources of attractants to supplement odour baits for the devices. The killing agents used should be environmentally safe, long lasting, and have different modes of action (other than pyrethroids as used on LLINs), to curb the risk of physiological insecticide resistance. PMID:23642306

An obstacle to building a time machine

NASA Astrophysics Data System (ADS)

Carroll, Sean M.; Farhi, Edward; Guth, Alan H.

1992-01-01

Gott (1991) has shown that a spacetime with two infinite parallel cosmic strings passing each other with sufficient velocity contains closed timelike curves. An attempt to build such a time machine is discussed. Using the energy-momentum conservation laws in the equivalent (2 + 1)-dimensional theory, the spacetime representing the decay of one gravitating particle into two is explicitly constructed; there is never enough mass in an open universe to build the time machine from the products of decays of stationary particles. More generally, the Gott time machine cannot exist in any open (2 + 1)-dimensional universe for which the total momentum is timelike.

Lattice QCD and the timelike pion form factor.

PubMed

Meyer, Harvey B

2011-08-12

We present a formula that allows one to calculate the pion form factor in the timelike region 2m(π) ≤ √(s) ≤ 4m(π) in lattice QCD. The form factor quantifies the contribution of two-pion states to the vacuum polarization. It must be known very accurately in order to reduce the theoretical uncertainty on the anomalous magnetic moment of the muon. At the same time, the formula constitutes a rare example where, in a restricted kinematic regime, the spectral function of a conserved current can be determined from Euclidean observables without an explicit analytic continuation.

Rigidly rotating zero-angular-momentum observer surfaces in the Kerr spacetime

NASA Astrophysics Data System (ADS)

Frolov, Andrei V.; Frolov, Valeri P.

2014-12-01

A stationary observer in the Kerr spacetime has zero angular momentum if their angular velocity ω has a particular value, which depends on the position of the observer. Worldlines of such zero-angular-momentum observers (ZAMOs) with the same value of the angular velocity ω form a three-dimensional surface, which has the property that the Killing vectors generating time translation and rotation are tangent to it. We call such a surface a rigidly rotating ZAMO surface. This definition allows for a natural generalization to the surfaces inside the black hole, where ZAMO trajectories formally become spacelike. A general property of such a surface is that there exist linear combinations of the Killing vectors with constant coefficients which make them orthogonal on it. In this paper we discuss properties of the rigidly rotating ZAMO surfaces both outside and inside the black hole and the relevance of these objects to a couple of interesting physical problems.

Evaluating the Vector Control Potential of the In2Care® Mosquito Trap Against Aedes aegypti and Aedes albopictus Under Semifield Conditions in Manatee County, Florida.

PubMed

Buckner, Eva A; Williams, Katie F; Marsicano, Ambyr L; Latham, Mark D; Lesser, Christopher R

2017-09-01

Successful integrated vector management programs may need new strategies in addition to conventional larviciding and adulticiding strategies to target Aedes aegypti and Ae. albopictus, which can develop in small, often cryptic, artificial and natural containers. The In2Care® mosquito trap was recently developed to target and kill larval and adult stages of these invasive container-inhabiting Aedes mosquitoes by utilizing autodissemination. Gravid females that visit the trap pick up pyriproxyfen (PPF) that they later transfer to nearby larval habitats as well as Beauveria bassiana spores that slowly kill them. We assessed the efficacy of the In2Care mosquito trap in a semifield setting against locally sourced strains of Ae. aegypti and Ae. albopictus. We found that the In2Care mosquito trap is attractive to gravid Ae. aegypti and Ae. albopictus females and serves as an egg sink, preventing any adult emergence from the trap (P = 0.0053 for both species). Adult females successfully autodisseminated PPF to surrounding water-filled containers, leading to a statistically significant reduction in new mosquito emergence (P ≤ 0.0002 for both species). Additionally, we found effective contamination with Beauveria bassiana spores, which significantly reduced the survivorship of exposed Ae. aegypti and Ae. albopictus (P ≤ 0.008 for both species in all experimental setups). In summary, the In2Care mosquito trap successfully killed multiple life stages of 2 main mosquito vector species found in Florida under semifield conditions.

The Kroll-Lee-Zumino Model and Pion Form Factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dominguez, C. A.; Loewe, M.

2010-08-04

At the one loop level, we make use of the renormalizable Abelian quantum field theory model of Kroll, Lee, and Zumino (KLZ) in order to compute the vertex corrections to the tree-level, Vector Meson Dominance (VMD) electromagnetic pion form factor. This result, together with the one-loop vacuum polarization contribution, implies an electromagnetic pion form factor which is in outstanding agreement with data in the whole range of accessible momentum transfers in the space-like region. The time-like form factor, which reproduces the Gounaris-Sakurai formula at and near the rho-meson peak, remains unaffected by the vertex correction at order O(g{sup 2}). Wemore » also use the KLZ model to compute the pion scalar radius at the one loop level, finding S = 0.40 fm{sup 2}. From this value we find for the low energy constant of chiral perturbation theory l{sub 4} = 3.4.« less

A lentiviral vector that activates latent human immunodeficiency virus-1 proviruses by the overexpression of tat and that kills the infected cells.

PubMed

Macías, David; Oya, Ricardo; Saniger, Luisa; Martín, Francisco; Luque, Francisco

2009-11-01

Despite the efficient HIV-1 replication blockage achieved with current highly active antiretroviral therapy (HAART) therapies, HIV-1 persists in the body and survives in a latent state that can last for the entire life of the patient. A long-lived reservoir of latently infected CD4(+) memory T cells represents the most important sanctuary for the virus and the greatest obstacle for viral eradication. In this work, we present an initial step toward a gene therapy approach aimed at the activation of latent provirus to induce the death of latently infected T cells. Latent HIV-1 infection is characterized by the failure of viral gene expression as a consequence of uninitiated or aborted transcription. We have constructed an HIV-1-based lentiviral vector (p5p53RTAT3) that expresses the viral trans-activating protein Tat in a drug-regulated manner and p53 in a Rev-dependent manner. We have demonstrated that the Tat-expressed protein from p5p53RTAT3 vector reactivates latent HIV-1 proviruses in J1.1 and ACH-2 cell lines and promotes p53-induced apoptosis in the presence of Rev. Our system was able to trigger the trans-activation of the provirus 5' long terminal repeat (LTR), stimulate the expression of the Rev protein from a tat-defective provirus, and provoke apoptosis selectively in the cells transfected with a tat-defective HIV-1 provirus in contrast to those with no HIV-1 provirus. However, the Rev-dependent p53 killing of latently infected cells was not effective enough for complete elimination of the awakened HIV-1 viruses. In summary, we have developed a vector system that is efficient in activating latent HIV-1 proviruses but that needs further improvement to kill infected cells.

The "heartbeat of the proton"

NASA Astrophysics Data System (ADS)

Weisskopf, Victor F.

Once Nino came to my office to tell me about his ideas of studying lepton pair production at PS. I was still not Director General, but Research Director at CERN. In addition to (e+e-) and (μ+μ-) pairs, he wanted to search for (e±μ∓) pairs as a signature of a new lepton carrying its own lepton number. He told me that if such a lepton existed with one GeV mass, it would have escaped detection in hadron accelerator experiments for two reasons: i) it would decay with a lifetime of order 10-11 sec and ii) because there is no π → μ mechanism for such a heavy new lepton: for its production a time-like photon would be needed. Time-like photons could be produced in hadronic interactions: for example in (bar{p}p) annihilation. This was before Lederman-Schwartz and Steinberger had discovered the two neutrinos. To think of a "sequential" Heavy Lepton and to work out the possible ways to get it in a hadron machine was for me extremely interesting Nino had just finished his first high precision work on the muon (g-2). It was some time after the Rochester Conference in 1960. I gave Nino the following suggestion: if you want to search for something so revolutionary as a Heavy Lepton carrying its own lepton number you should work out a proposal for a series of experiments where the study of lepton pairs (e+e-) and (μ+μ-) could be justified in terms of physics accepted by the community. In addition a high intensity antiproton beam was needed. He came later to tell me that he had two very good friends, both excellent engineers: Mario Morpurgo and Guido Petrucci. A very high intensity antiproton beam could be built to study the electromagnetic form factor of the proton in the time-like region. If the proton was "point-like" in the time-like region, the rate of time-like photons yielding (e+e-) and (μ+μ-) pairs could be accessible to experimental observation, thus allowing to establish some limits on the new Heavy Lepton mass, or to see it, via the (e±μ∓) channel. The "official" theme was: to establish if the proton had a structure or not in the time-like region. Thus a powerful system able to detect (e+e-) and (μ+μ-) pairs could be built. Nino established in 1963 the existence of a time-like structure of the proton studying the (e+e-) channel and in 1964 studying the (μ+μ-) channel. The set up was able to do what he wanted: a simultaneous detection of electrons and μ pairs, therefore (e±μ∓) as well. Unfortunately the proton was not a point-like particle in the time-like region and therefore the source of time-like photons originated in (bar{p}p) annihilation was very depressed. In fact, using the (e+e-) and the (μ+μ-) channels, Nino established that at 6.8 (GeV/c)2 time-like four momentum transfer, the crosssection was 500 times below the expected point-like value. This result had attracted a lot of attention. Bogoliubov was very interested when in 1964 Nino went to Dubna to present the (μ+μ-) results at the International Conference on "High Energy Physics". Yang had a model that predicted a point-like structure of the proton in the time-like region. I called this series of experiments as measuring the "heartbeat of the proton". Of course there were no (e±μ∓) events, neither in the (bar{p}p) nor in the (μ-p) channel. Nevertheless a series of experiments was performed on "standard" physics, such as the discovery of many rare decay modes of mesons and the measurement of the (φ-ϕ) mixing. All these experiments could be done because Nino had invented what is now known as the "preshower" method to reject with high efficiency pions in favor of "electrons". Once it was clear that in hadronic interactions there are very few time-like photons, he asked me if I would give green light in order to consider the use of the (e±μ∓) technology in the newly being developed Frascati (e+e-) method would have been the best in order to see if a Heavy Lepton carrying its own lepton number existed. Of course he got the green light and in 1970 he got the first limit on the Heavy Lepton mass together with a series of high precision QED measurements. But one story I will never forget in connection with the "heartbeat of the proton". After he succeeded with his friends Mario (Morpurgo) and Guido (Petrucci) to build the highest intensity antiproton beam at CERN, Nino came to my office and said more or less the following: "Viki, by changing the voltage of the electrostatic separator and a few other trivial details, in one night, I will be able to establish if the antideuteron exists with the correct expected deuteron mass". I told him that this was an experiment where he would get the Nobel prize if he found nothing. "But, there is a but", I added. "If you do not succeed in one night and if you destroy the beam, then I will not defend you. My green light is only valid if you really can check the existence of the antideuteron in a single night". Next morning, when I arrived at CERN, Nino was there with his graph where the antideuteron signal was exactly where it was expected to be. I remember the year, 1965, not the day. It was (and is) the birthday of Peter Standley who was at that time the PS Division Leader. I called him in my office and the antideuteron discovery at CERN was my and Nino's gift to our mutual friend Peter. I decided not to have a press-release and Nino agreed. A few weeks later we read in the newspaper that the antideuteron had been discovered by Lederman and Ting in the United States. They had decided to have a press-release. Nevertheless Nino's paper in Nuovo Cimento preceeds Leon's and Sam's publication in Physical Review.

Information carrying capacity of a cosmological constant

NASA Astrophysics Data System (ADS)

Simidzija, Petar; Martín-Martínez, Eduardo

2017-01-01

We analyze the exchange of information in different cosmological backgrounds when sender and receiver are timelike separated and communicate through massless fields (without the exchange of light signals). Remarkably, we show that the dominance of a cosmological constant makes the amount of recoverable information imprinted in the field by the sender extremely resilient: it does not decay in time or with the spatial separation of the sender and receiver, and it actually increases with the rate of expansion of the Universe. This is in stark contrast with the information carried by conventional light signals and with previous results on timelike communication through massless fields in matter-dominated cosmologies.

Targeted application of an organophosphate-based paint applied on windows and doors against Anopheles coluzzii resistant to pyrethroids under real life conditions in Vallée du Kou, Burkina Faso (West Africa).

PubMed

Poda, Serge B; Soma, Dieudonné D; Hien, Aristide; Namountougou, Moussa; Gnankiné, Olivier; Diabaté, Abdoulaye; Fournet, Florence; Baldet, Thierry; Mas-Coma, Santiago; Mosqueira, Beatriz; Dabiré, Roch K

2018-04-02

A novel strategy applying an organophosphate-based insecticide paint on doors and windows in combination with long-lasting insecticide-treated nets (LLINs) was tested for the control of pyrethroid-resistant malaria vectors in a village setting in Vallée du Kou, a rice-growing area west of Burkina Faso. Insecticide Paint Inesfly 5A IGR™, comprised of two organophosphates and an insect growth regulator, was applied to doors and windows and tested in combination with pyrethroid-treated LLINs. The killing effect was monitored for 5 months by early morning collections of anophelines and other culicids. The residual efficacy was evaluated monthly by WHO bioassays using Anopheles gambiae 'Kisumu' and local populations of Anopheles coluzzii resistant to pyrethroids. The spatial mortality efficacy (SME) at distances of 1 m was also assessed against pyrethroid-susceptible and -resistant malaria vectors. The frequency of L1014F kdr and Ace-1 R G119S mutations was, respectively, reported throughout the study. The Insecticide Paint Inesfly 5A IGR had been tested in past studies yielding a long-term mortality rate of 80% over 12 months against An. coluzzii, the local pyrethroid-resistant malaria vector. The purpose of the present study is to test if treating smaller, targeted surfaces (e.g. doors and windows) was also efficient in killing malaria vectors. Treating windows and doors alone yielded a killing efficacy of 100% for 1 month against An. coluzzii resistant to pyrethroids, but efficacy reduced quickly afterwards. Likewise, WHO cone bioassays yielded mortalities of 80-100% for 2 months but declined to 90 and 40% 2 and 3 months after treatment, respectively. Mosquitoes exposed to insecticide paint-treated surfaces at distances of 1 m, yielded mortality rates of about 90-80% against local pyrethroids-resistant An. coluzzii during the first 2 months, but decreased to 30% afterwards. Anopheles coluzzii was reported to be exclusively the local malaria vector and resistant to pyrethroids with high L1014 kdr frequency. The combination of insecticide paint on doors and windows with LLINs yielded high mortality rates in the short term against wild pyrethroid-resistant malaria vector populations. A high SME was observed against laboratory strains of pyrethroid-resistant malaria vectors placed for 30 min at 1 m from the treated/control walls. The application of the insecticide paint on doors and windows led to high but short-lasting mortality rates. The strategy may be an option in a context where low cost, rapid responses need to be implemented in areas where malaria vectors are resistant to pyrethroids.

Gravitational waves in Einstein-æther and generalized TeVeS theory after GW170817

NASA Astrophysics Data System (ADS)

Gong, Yungui; Hou, Shaoqi; Liang, Dicong; Papantonopoulos, Eleftherios

2018-04-01

In this work we discuss the polarization contents of Einstein-æther theory and the generalized tensor-vector-scalar (TeVeS) theory, as both theories have a normalized timelike vector field. We derive the linearized equations of motion around the flat spacetime background using the gauge-invariant variables to easily separate physical degrees of freedom. We find the plane wave solutions and identify the polarizations by examining the geodesic deviation equations. We find that there are five polarizations in Einstein-æther theory and six polarizations in the generalized TeVeS theory. In particular, the transverse breathing mode is mixed with the pure longitudinal mode. We also discuss the experimental tests of the extra polarizations in Einstein-æther theory using pulsar timing arrays combined with the gravitational-wave speed bound derived from the observations on GW 170817 and GRB 170817A. It turns out that it might be difficult to use pulsar timing arrays to distinguish different polarizations in Einstein-æther theory. The same speed bound also forces one of the propagating modes in the generalized TeVeS theory to travel much faster than the speed of light. Since the strong coupling problem does not exist in some parameter subspaces, the generalized TeVeS theory is excluded in these parameter subspaces.

Quasi-two-body decays B(s )→P ρ →P π π in the perturbative QCD approach

NASA Astrophysics Data System (ADS)

Li, Ya; Ma, Ai-Jun; Wang, Wen-Fei; Xiao, Zhen-Jun

2017-03-01

In this work, we calculate the C P -averaged branching ratios and the direct C P -violating asymmetries of the quasi-two-body decays B(s )→P (ρ →)π π by employing the perturbative QCD (PQCD) approach (here P stands for a light pseudoscalar meson π , K , η or η'). The vector current timelike form factor Fπ, which contains the final-state interactions between the pion pair in the resonant region associated with the P -wave states ρ (770 ) along with the two-pion distribution amplitudes, is employed to describe the interactions between the ρ and the pion pair under the hypothesis of the conserved vector current. We found that (a) the PQCD predictions for the branching ratios and the direct C P -violating asymmetries for most considered B(s )→P (ρ →)π π decays agree with currently available data within errors, (b) for B (B →π0ρ0→π0(π+π-) , the PQCD prediction is much smaller than the measured one, and (c) for the B+→π+(ρ0→)π+π- decay mode, there is a negative C P asymmetry (-27.5-3.7+3.0)% , which agrees with other theoretical predictions but is different in sign from those reported by the BABAR and LHCb Collaborations.

Optical trapping of core-shell magnetic microparticles by cylindrical vector beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhong, Min-Cheng; Gong, Lei; Li, Di

2014-11-03

Optical trapping of core-shell magnetic microparticles is experimentally demonstrated by using cylindrical vector beams. Second, we investigate the optical trapping efficiencies. The results show that radially and azimuthally polarized beams exhibit higher axial trapping efficiencies than the Gaussian beam. Finally, a trapped particle is manipulated to kill a cancer cell. The results make possible utilizing magnetic particles for optical manipulation, which is an important advantage for magnetic particles as labeling agent in targeted medicine and biological analysis.

Euclidean supersymmetric solutions with the self-dual Weyl tensor

NASA Astrophysics Data System (ADS)

Nozawa, Masato

2017-07-01

We explore the Euclidean supersymmetric solutions admitting the self-dual gauge field in the framework of N = 2 minimal gauged supergravity in four dimensions. According to the classification scheme utilizing the spinorial geometry or the bilinears of Killing spinors, the general solution preserves one quarter of supersymmetry and is described by the Przanowski-Tod class with the self-dual Weyl tensor. We demonstrate that there exists an additional Killing spinor, provided the Przanowski-Tod metric admits a Killing vector that commutes with the principal one. The proof proceeds by recasting the metric into another Przanowski-Tod form. This formalism enables us to show that the self-dual Reissner-Nordström-Taub-NUT-AdS metric possesses a second Killing spinor, which has been missed over many years. We also address the supersymmetry when the Przanowski-Tod space is conformal to each of the self-dual ambi-toric Kähler metrics. It turns out that three classes of solutions are all reduced to the self-dual Carter family, by virtue of the nondegenerate Killing-Yano tensor.

LETTER TO THE EDITOR: A theorem on topologically massive gravity

NASA Astrophysics Data System (ADS)

Aliev, A. N.; Nutku, Y.

1996-03-01

We show that for three dimensional spacetimes admitting a hypersurface orthogonal Killing vector field, Deser, Jackiw and Templeton's vacuum field equations of topologically massive gravity allow only the trivial flat spacetime solution. Thus spin is necessary to support topological mass.

Diffeomorphism invariance and black hole entropy

NASA Astrophysics Data System (ADS)

Huang, Chao-Guang; Guo, Han-Ying; Wu, Xiaoning

2003-11-01

The Noether-charge and the Hamiltonian realizations for the diff(M) algebra in diffeomorphism-invariant gravitational theories without a cosmological constant in any dimension are studied in a covariant formalism. We analyze how the Hamiltonian functionals form the diff(M) algebra under the Poisson brackets and show how the Noether charges with respect to the diffeomorphism generated by the vector fields and their variations in n-dimensional general relativity form this algebra. The asymptotic behaviors of vector fields generating diffeomorphism of the manifold with boundaries are discussed. It is shown that the “central extension” for a large class of vector fields is always zero on the Killing horizon. We also check whether choosing the vector fields near the horizon may pick up the Virasoro algebra. The conclusion is unfortunately negative in any dimension.

Potentialities of Mermithid Nematodes for the Biocontrol of Blackflies (Diptera: Simuliidae)--A Review,

DTIC Science & Technology

biocontrol agents of agricultural insect pests and medically important insect vectors. More specifically, mermithid nematodes appear to regulate natural...Mermithids comprise a family of nematodes which invariably kill/sterilize their insect host(s). These nematodes have considerable potential as

Classical aspects of higher spin topologically massive gravity

NASA Astrophysics Data System (ADS)

Chen, Bin; Long, Jiang; Zhang, Jian-Dong

2012-10-01

We study the classical solutions of three-dimensional topologically massive gravity (TMG) and its higher spin generalization, in the first-order formulation. The action of higher spin TMG has been proposed by Chen and Long (2011 J. High Energy Phys. JHEP12(2011)114) to be of a Chern-Simons-like form. The equations of motion are more complicated than the ones in pure higher spin AdS3 gravity, but are still tractable. As all the solutions in higher spin gravity are automatically the solutions of higher spin TMG, we focus on other solutions. We manage to find the AdS pp-wave solutions with higher spin hair and find that the non-vanishing higher spin fields may or may not modify the pp-wave geometry. In order to discuss the warped spacetime, we introduce the notion of a special Killing vector, which is defined to be the symmetry on the frame-like fields. We reproduce various warped spacetimes of TMG in our framework, with the help of special Killing vectors.

Is drought helping or killing dengue? Investigation of spatiotemporal relationship between dengue fever and drought

NASA Astrophysics Data System (ADS)

Lee, Chieh-Han; Yu, Hwa-Lung

2015-04-01

Dengue Fever is a vector-borne disease that is transmitted between human and mosquitos in tropical and sub-tropical regions. Previous studies have found significant relationship between the epidemic of dengue cases and climate variables, especially temperature and precipitation. Besides, the natural phenomena (e.g., drought) are considered that significantly drop the number of dengue cases by killing vector's breeding environment. However, in Kaohsiung City, Taiwan, there are evidences that the temporal pattern of dengue is correlated to drought events. Kaohsiung City experienced two main dengue outbreaks in 2002 and 2014 that both years were confirmed with serious drought. Especially in 2014, Kaohsiung City was suffered from extremely dengue outbreak in 2014 that reported the highest number of dengue cases in the history. This study constructs the spatiotemporal model of dengue incidences and index of drought events (Standardized Precipitation Index, SPI) based on the distributed lag nonlinear model (DLNM). Other meteorological measures are also included in the analysis.

VizieR Online Data Catalog: ynogkm: code for calculating time-like geodesics (Yang+, 2014)

NASA Astrophysics Data System (ADS)

Yang, X.-L.; Wang, J.-C.

2013-11-01

Here we present the source file for a new public code named ynogkm, aim on calculating the time-like geodesics in a Kerr-Newmann spacetime fast. In the code the four Boyer-Lindquis coordinates and proper time are expressed as functions of a parameter p semi-analytically, i.e., r(p), μ(p), φ(p), t(p), and σ(p), by using the Weiers- trass' and Jacobi's elliptic functions and integrals. All of the ellip- tic integrals are computed by Carlson's elliptic integral method, which guarantees the fast speed of the code.The source Fortran file ynogkm.f90 contains three modules: constants, rootfind, ellfunction, and blcoordinates. (3 data files).

Multiparticle Solutions in 2+1 Gravity and Time Machines

NASA Astrophysics Data System (ADS)

Steif, Alan R.

Multiparticle solutions for sources moving at the speed of light and corresponding to superpositions of single-particle plane-wave solutions are constructed in 2+1 gravity. It is shown that the two-particle spacetimes admit closed timelike curves provided the center-of-momentum energy exceeds a certain critical value. This occurs, however, at the cost of unphysical boundary conditions which are analogous to those affecting Gott’s time machine. As the energy exceeds the critical value, the closed timelike curves first occur at spatial infinity, then migrate inward as the energy is further increased. The total mass of the system also becomes imaginary for particle energies greater than the critical value.

A type N radiation field solution with Λ <0 in a curved space-time and closed time-like curves

NASA Astrophysics Data System (ADS)

Ahmed, Faizuddin

2018-05-01

An anti-de Sitter background four-dimensional type N solution of the Einstein's field equations, is presented. The matter-energy content pure radiation field satisfies the null energy condition (NEC), and the metric is free-from curvature divergence. In addition, the metric admits a non-expanding, non-twisting and shear-free geodesic null congruence which is not covariantly constant. The space-time admits closed time-like curves which appear after a certain instant of time in a causally well-behaved manner. Finally, the physical interpretation of the solution, based on the study of the equation of the geodesics deviation, is analyzed.

Weak lensing in a plasma medium and gravitational deflection of massive particles using the Gauss-Bonnet theorem. A unified treatment

NASA Astrophysics Data System (ADS)

Crisnejo, Gabriel; Gallo, Emanuel

2018-06-01

We apply the Gauss-Bonnet theorem to the study of light rays in a plasma medium in a static and spherically symmetric gravitational field and also to the study of timelike geodesics followed for test massive particles in a spacetime with the same symmetries. The possibility of using the theorem follows from a correspondence between timelike curves followed by light rays in a plasma medium and spatial geodesics in an associated Riemannian optical metric. A similar correspondence follows for massive particles. For some examples and applications, we compute the deflection angle in weak gravitational fields for different plasma density profiles and gravitational fields.

[Climate change - a pioneer for the expansion of canine vector-borne diseases?].

PubMed

Krämer, F; Mencke, N

2011-01-01

Vector-transmitted diseases are one of the major contributors to the global burden of disease in humans and animals. Climate change is consistently held responsible for the spread of parasitic acarid and insect vectors such as ticks, fleas, sand flies and mosquitoes, and their transmitted pathogens (in the case of the dog the so-called canine vector-borne diseases [CVBD]). Currently, there is only insufficient data available to prove whether climate change is a major driving force for vector and disease expansion, but the evidence is growing. Other reasons, such as ecological, demographic and socio-economic factors, e.g. pet travel into and pet import from endemic areas, also play a role in this development. Apart from all the controversial discussion of the factors leading to vector and disease expansion, preventative measures should include dog owners' education as they are responsible for individual parasite protection as well as for the minimisation of adverse risk behaviour, e.g. regarding pet travel. Broad-spectrum vector control should be practised by using parasiticides that repel and kill blood feeders in order to minimize the risk of CVBD-pathogen transmission.

Sildenafil (Viagra) sensitizes prostate cancer cells to doxorubicin-mediated apoptosis through CD95

PubMed Central

Das, Anindita; Durrant, David; Mitchell, Clint; Dent, Paul; Batra, Surinder K.; Kukreja, Rakesh C.

2016-01-01

We previously reported that Sildenafil enhances apoptosis and antitumor efficacy of doxorubicin (DOX) while attenuating its cardiotoxic effect in prostate cancer. In the present study, we investigated the mechanism by which sildenafil sensitizes DOX in killing of prostate cancer (PCa) cells, DU145. The death receptor Fas (APO-1 or CD95) induces apoptosis in many carcinoma cells, which is negatively regulated by anti-apoptotic molecules such as FLIP (Fas-associated death domain (FADD) interleukin-1-converting enzyme (FLICE)-like inhibitory protein). Co-treatment of PCa cells with sildenafil and DOX for 48 hours showed reduced expression of both long and short forms of FLIP (FLIP-L and -S) as compared to individual drug treatment. Over-expression of FLIP-s with an adenoviral vector attentuated the enhanced cell-killing effect of DOX and sildenafil. Colony formation assays also confirmed that FLIP-S over-expression inhibited the DOX and sildenafil-induced synergistic killing effect as compared to the cells infected with an empty vector. Moreover, siRNA knock-down of CD95 abolished the effect of sildenafil in enhancing DOX lethality in cells, but had no effect on cell killing after treatment with a single agent. Sildenafil co-treatment with DOX inhibited DOX-induced NF-κB activity by reducing phosphorylation of IκB and nuclear translocation of the p65 subunit, in addition to down regulation of FAP-1 (Fas associated phosphatase-1, a known inhibitor of CD95-mediated apoptosis) expression. This data provides evidence that the CD95 is a key regulator of sildenafil and DOX mediated enhanced cell death in prostate cancer. PMID:26716643

Insecticide-impregnated netting as a potential tool for long-lasting control of the leishmaniasis vector Lutzomyia longipalpis in animal shelters

PubMed Central

2013-01-01

Background Leishmaniasis remains a serious neglected disease, with more than 350 million people potentially at risk worldwide. Control strategies often rely on spraying residual insecticides to target populations of the sand fly vectors that transmit Leishmania parasites when blood-feeding. These programmes are often difficult to sustain effectively, as sand fly resting sites must be resprayed on a regular basis. Here, we investigate whether application of insecticide-impregnated netting to a surface could act as an alternative to residual spraying for controlling the American visceral leishmaniasis vector Lutzomyia longipalpis. Methods Female L. longipalpis from our laboratory colony were exposed for 1 h to three treatments applied to plywood surfaces: 2% permethrin-impregnated netting (Olyset®), 20 mg a.i.m-2 micro-encapsulated lambda-cyhalothrin (Demand CS®) and a no-treatment control. We compared the speed at which these treatments acted, by measuring the percentage of sand flies killed both immediately after exposure to the treatment for 1 hour, as well as the number that had died 24 h after the 1 hour exposure. We repeated the experiment at 6 and 12 months following application to test the effectiveness of each treatment over time. Results When first applied, the lambda-cyhalothrin killed more sand flies in the first hour than the permethrin-impregnated netting. However, the effectiveness of the lambda-cyhalothrin diminished over time, so that there was no difference between the two treatments at 12 months. Both killed more sand flies than the control. When measured 24 h following exposure, both test treatments had killed close to 100% of sand flies when first applied, but while the lethal effect of the netting was maintained at close to 100% over 12 months, the effectiveness of the residual insecticide diminished to approximately 80% after 6 months. Conclusions The results of these initial laboratory experiments indicate that covering surfaces with insecticide impregnated netting material may provide a longer-lasting solution for killing sand flies than residual spraying. Field trials are needed to identify the feasibility of treating surfaces with netting or similar impregnated materials as part of a control program. In targeting L. longipalpis, the greatest benefits may be seen in treating animal sheds with netting, where these sand flies aggregate in large numbers, and which can be difficult to treat repeatedly by conventional spraying. PMID:23642213

No-Hypersignaling Principle

NASA Astrophysics Data System (ADS)

Dall'Arno, Michele; Brandsen, Sarah; Tosini, Alessandro; Buscemi, Francesco; Vedral, Vlatko

2017-07-01

A paramount topic in quantum foundations, rooted in the study of the Einstein-Podolsky-Rosen (EPR) paradox and Bell inequalities, is that of characterizing quantum theory in terms of the spacelike correlations it allows. Here, we show that to focus only on spacelike correlations is not enough: we explicitly construct a toy model theory that, while not contradicting classical and quantum theories at the level of spacelike correlations, still displays an anomalous behavior in its timelike correlations. We call this anomaly, quantified in terms of a specific communication game, the "hypersignaling" phenomena. We hence conclude that the "principle of quantumness," if it exists, cannot be found in spacelike correlations alone: nontrivial constraints need to be imposed also on timelike correlations, in order to exclude hypersignaling theories.

No-Hypersignaling Principle.

PubMed

Dall'Arno, Michele; Brandsen, Sarah; Tosini, Alessandro; Buscemi, Francesco; Vedral, Vlatko

2017-07-14

A paramount topic in quantum foundations, rooted in the study of the Einstein-Podolsky-Rosen (EPR) paradox and Bell inequalities, is that of characterizing quantum theory in terms of the spacelike correlations it allows. Here, we show that to focus only on spacelike correlations is not enough: we explicitly construct a toy model theory that, while not contradicting classical and quantum theories at the level of spacelike correlations, still displays an anomalous behavior in its timelike correlations. We call this anomaly, quantified in terms of a specific communication game, the "hypersignaling" phenomena. We hence conclude that the "principle of quantumness," if it exists, cannot be found in spacelike correlations alone: nontrivial constraints need to be imposed also on timelike correlations, in order to exclude hypersignaling theories.

Towards extracting the timelike pion form factor on CLS twoflavour ensembles

NASA Astrophysics Data System (ADS)

Erben, Felix; Green, Jeremy; Mohler, Daniel; Wittig, Hartmut

2018-03-01

Results are presented from an ongoing study of the ρ resonance. The focus is on CLS 2-flavour ensembles generated using O(a) improved Wilson fermions with pion masses ranging from 265 to 437 MeV. The energy levels are extracted by solving the GEVP of correlator matrices, created with the distillation approach involving ρ and ππ interpolators. The study is done in the centre-of-mass frame and several moving frames. One aim of this work is to extract the timelike pion form factor after applying the Lüscher formalism. We therefore plan to integrate this study with the existing Mainz programme for the calculation of the hadronic vacuum polarization contribution to the muon g - 2.

Timelike naked singularity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goswami, Rituparno; Joshi, Pankaj S.; Vaz, Cenalo

We construct a class of spherically symmetric collapse models in which a naked singularity may develop as the end state of collapse. The matter distribution considered has negative radial and tangential pressures, but the weak energy condition is obeyed throughout. The singularity forms at the center of the collapsing cloud and continues to be visible for a finite time. The duration of visibility depends on the nature of energy distribution. Hence the causal structure of the resulting singularity depends on the nature of the mass function chosen for the cloud. We present a general model in which the naked singularitymore » formed is timelike, neither pointlike nor null. Our work represents a step toward clarifying the necessary conditions for the validity of the Cosmic Censorship Conjecture.« less

Complete integrability of geodesic motion in Sasaki-Einstein toric Yp,q spaces

NASA Astrophysics Data System (ADS)

Babalic, Elena Mirela; Visinescu, Mihai

2015-09-01

We construct explicitly the constants of motion for geodesics in the five-dimensional Sasaki-Einstein spaces Yp,q. To carry out this task, we use the knowledge of the complete set of Killing vectors and Killing-Yano tensors on these spaces. In spite of the fact that we generate a multitude of constants of motion, only five of them are functionally independent implying the complete integrability of geodesic flow on Yp,q spaces. In the particular case of the homogeneous Sasaki-Einstein manifold T1,1 the integrals of motion have simpler forms and the relations between them are described in detail.

Conformal killing tensors and covariant Hamiltonian dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cariglia, M., E-mail: marco@iceb.ufop.br; Gibbons, G. W., E-mail: G.W.Gibbons@damtp.cam.ac.uk; LE STUDIUM, Loire Valley Institute for Advanced Studies, Tours and Orleans

2014-12-15

A covariant algorithm for deriving the conserved quantities for natural Hamiltonian systems is combined with the non-relativistic framework of Eisenhart, and of Duval, in which the classical trajectories arise as geodesics in a higher dimensional space-time, realized by Brinkmann manifolds. Conserved quantities which are polynomial in the momenta can be built using time-dependent conformal Killing tensors with flux. The latter are associated with terms proportional to the Hamiltonian in the lower dimensional theory and with spectrum generating algebras for higher dimensional quantities of order 1 and 2 in the momenta. Illustrations of the general theory include the Runge-Lenz vector formore » planetary motion with a time-dependent gravitational constant G(t), motion in a time-dependent electromagnetic field of a certain form, quantum dots, the Hénon-Heiles and Holt systems, respectively, providing us with Killing tensors of rank that ranges from one to six.« less

Regular black holes: Electrically charged solutions, Reissner-Nordstroem outside a de Sitter core

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lemos, Jose P. S.; Zanchin, Vilson T.; Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adelia, 166, 09210-170, Santo Andre, Sao Paulo

2011-06-15

To have the correct picture of a black hole as a whole, it is of crucial importance to understand its interior. The singularities that lurk inside the horizon of the usual Kerr-Newman family of black hole solutions signal an endpoint to the physical laws and, as such, should be substituted in one way or another. A proposal that has been around for sometime is to replace the singular region of the spacetime by a region containing some form of matter or false vacuum configuration that can also cohabit with the black hole interior. Black holes without singularities are called regularmore » black holes. In the present work, regular black hole solutions are found within general relativity coupled to Maxwell's electromagnetism and charged matter. We show that there are objects which correspond to regular charged black holes, whose interior region is de Sitter, whose exterior region is Reissner-Nordstroem, and the boundary between both regions is made of an electrically charged spherically symmetric coat. There are several types of solutions: regular nonextremal black holes with a null matter boundary, regular nonextremal black holes with a timelike matter boundary, regular extremal black holes with a timelike matter boundary, and regular overcharged stars with a timelike matter boundary. The main physical and geometrical properties of such charged regular solutions are analyzed.« less

Consistent compactification of double field theory on non-geometric flux backgrounds

NASA Astrophysics Data System (ADS)

Hassler, Falk; Lüst, Dieter

2014-05-01

In this paper, we construct non-trivial solutions to the 2 D-dimensional field equations of Double Field Theory (DFT) by using a consistent Scherk-Schwarz ansatz. The ansatz identifies 2( D - d) internal directions with a twist U M N which is directly connected to the covariant fluxes ABC . It exhibits 2( D - d) linear independent generalized Killing vectors K I J and gives rise to a gauged supergravity in d dimensions. We analyze the covariant fluxes and the corresponding gauged supergravity with a Minkowski vacuum. We calculate fluctuations around such vacua and show how they gives rise to massive scalars field and vectors field with a non-abelian gauge algebra. Because DFT is a background independent theory, these fields should directly correspond the string excitations in the corresponding background. For ( D - d) = 3 we perform a complete scan of all allowed covariant fluxes and find two different kinds of backgrounds: the single and the double elliptic case. The later is not T-dual to a geometric background and cannot be transformed to a geometric setting by a field redefinition either. While this background fulfills the strong constraint, it is still consistent with the Killing vectors depending on the coordinates and the winding coordinates, thereby giving a non-geometric patching. This background can therefore not be described in Supergravity or Generalized Geometry.

Wingnut (Juglandaceae) as a new generic host for Pityophthorus juglandis (Coleoptera: Curculionidae) and the thousand cankers disease pathogen, Geosmithia morbida (Ascomycota: Hypocreales)

Treesearch

Stacy M. Hishinuma; Paul L. Dallara; Mohammad A. Yaghmour; Marcelo M. Zerillo; Corwin M. Parker; Tatiana V. Roubtsova; Tivonne L. Nguyen; Ned A. Tisserat; Richard M. Bostock; Mary L. Flint; Steven J. Seybold

2016-01-01

The walnut twig beetle (WTB), Pityophthorus juglandis Blackman (Coleoptera: Curculionidae), vectors a fungus, Geosmithia morbida Kolarík, Freeland, Utley, and Tisserat (Ascomycota: Hypocreales), which colonises and kills the phloem of walnut and butternut trees, Juglans Linnaeus (Juglandaceae). Over the...

Influence of temperature and humidity on the viability of Ophiognomonia clavigignenti-juglandacearum Conidia

Treesearch

M.J. Moore; M.E. Ostry

2015-01-01

Butternut canker, caused by the fungus Ophiognomonia clavigignenti-juglandacearum, primarily kills butternut (Juglans cinerea). Rain splash and local air currents are the primary means of conidia dispersal but that does not explain its long-distance spread and infection of isolated trees. Dispersal by insect or animal vectors...

Population trends of the redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae): does utilization of small diameter redbay trees allow populations to persist?

Treesearch

M. Lake Maner; James Hanula; Scott Horn

2014-01-01

The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, vectors laurel wilt, Raffaelea lauricola T.C. Harr., Fraedrich & Aghayeva, that quickly kills all large diam (> 2.5cm) redbay trees [Persea borbonia (L.) Sprengel] in an area but smaller diam trees (

Invasive Bark Beetles, Forest Insect& Disease Leaflet 176

Treesearch

J.C. Lee; R.A. Haack; J.F. Negron; J.J. Witcosky; S.J. Seybold

2007-01-01

Bark beetles (Scolytidae) are among the most damaging insects in Northern Hemisphere forests, killing trees by direct feeding and by vectoring fungal pathogens. In addition to an already formidable native bark beetle complex, the number of exotic scolytids in U.S. forests has increased rapidly, with 53 known species established as of June 2007.

Conserved charges of black holes in Weyl and Einstein-Gauss-Bonnet gravities

NASA Astrophysics Data System (ADS)

Peng, Jun-Jin

2014-11-01

An off-shell generalization of the Abbott-Deser-Tekin (ADT) conserved charge was recently proposed by Kim et al. They achieved this by introducing off-shell Noether currents and potentials. In this paper, we construct the crucial off-shell Noether current by the variation of the Bianchi identity for the expression of EOM, with the help of the property of Killing vector. Our Noether current, which contains an additional term that is just one half of the Lie derivative of a surface term with respect to the Killing vector, takes a different form in comparison with the one in their work. Then we employ the generalized formulation to calculate the quasi-local conserved charges for the most general charged spherically symmetric and the dyonic rotating black holes with AdS asymptotics in four-dimensional conformal Weyl gravity, as well as the charged spherically symmetric black holes in arbitrary dimensional Einstein-Gauss-Bonnet gravity coupled to Maxwell or nonlinear electrodynamics in AdS spacetime. Our results confirm those obtained through other methods in the literature.

Sterculia guttata seeds extractives--an effective mosquito larvicide.

PubMed

Katade, Sushama R; Pawar, Pushpa V; Wakharkar, Radhika D; Deshpande, Nirmala R

2006-08-01

The larvicidal activity of ethanol, chloroform and hexane soxhlet extracts obtained from S. guttata seeds was investigated against the IVth instar larvae of Dengue fever vector, Aedes aegypti and filarial vector, Culex quinquefasciatus. All extracts including fractions of ethanol extract exhibited 100% larval kill within 24 hr exposure period at 500 ppm concentration. Fraction A1 of ethanol was found to be most promising; its LC50 was 21.552 and 35.520 ppm against C. quinquefasciatus and A. aegypti respectively. Naturally occurring S. guttata seed derived fractions merit further study as potential mosquito larval control agents or lead compounds.

MALBEC: a new CUDA-C ray-tracer in general relativity

NASA Astrophysics Data System (ADS)

Quiroga, G. D.

2018-06-01

A new CUDA-C code for tracing orbits around non-charged black holes is presented. This code, named MALBEC, take advantage of the graphic processing units and the CUDA platform for tracking null and timelike test particles in Schwarzschild and Kerr. Also, a new general set of equations that describe the closed circular orbits of any timelike test particle in the equatorial plane is derived. These equations are extremely important in order to compare the analytical behavior of the orbits with the numerical results and verify the correct implementation of the Runge-Kutta algorithm in MALBEC. Finally, other numerical tests are performed, demonstrating that MALBEC is able to reproduce some well-known results in these metrics in a faster and more efficient way than a conventional CPU implementation.

Isolation of fungi from dead arthropods and identification of a new mosquito natural pathogen.

PubMed

Jaber, Sana; Mercier, Alex; Knio, Khouzama; Brun, Sylvain; Kambris, Zakaria

2016-09-05

Insects are well known vectors of human and animal pathogens and millions of people are killed by mosquito-borne diseases every year. The use of insecticides to target insect vectors has been hampered by the issues of toxicity to the environment and by the selection of resistant insects. Therefore, biocontrol strategies based on naturally occurring microbial pathogens emerged as a promising control alternative. The entomopathogenic fungus Beauveria bassiana is well characterized and have been approved by the United States Environmental Protection Agency as a pest biological control method. However, thousands of other fungi are unexploited and it is important to identify and use different fungi for biocontrol with possibly some vector specific strains. The aim of this study was to identify new fungal entomopathogens that may be used as potential mosquito biocontrol agents. Cadavers of arthropods were collected from pesticide free areas and the fungi associated isolated, cultured and identified. Then the ability of each isolate to kill laboratory insects was assayed and compared to that of B. bassiana. In total we have isolated and identified 42 fungal strains from 17 different arthropod cadavers. Twenty four fungal isolates were cultivated in the laboratory and were able to induce sporulation. When fungal spores were microinjected into Drosophila melanogaster, eight isolates proved to be highly pathogenic while the remaining strains showed moderate or no pathogenicity. Then a selection of isolates was tested against Aedes mosquitoes in a model mimicking natural infections. Only one fungus (Aspergillus nomius) was as pathogenic as B. bassiana and able to kill 100 % of the mosquitoes. The obtained results are encouraging and demonstrate the feasibility of this simple approach for the identification of new potential mosquito killers. Indeed, it is essential to anticipate and prepare biocontrol methods to fight the expansion of mosquitoes' habitat predicted in certain geographical areas in association with the occurring climatic changes.

Ebola virus vaccine: benefit and risks of adenovirus-based vectors.

PubMed

Mennechet, Franck J D; Tran, Thi Thu Phuong; Eichholz, Karsten; van de Perre, Philippe; Kremer, Eric J

2015-01-01

In 2014, an outbreak of Ebola virus spread rapidly in West Africa. The epidemic killed more than 10,000 people and resulted in transmissions outside the endemic countries. WHO hopes for effective vaccines by the end of 2015. Numerous vaccine candidates have been proposed, and several are currently being evaluated in humans. Among the vaccine candidates are vectors derived from adenovirus (Ad). Despite previous encouraging preclinical and Phase I/II trials, Ad vectors used in three Phase II trials targeting HIV were prematurely interrupted because of the lack of demonstrated efficacy. The vaccine was not only ineffective but also led to a higher rate of HIV acquisition. In this context, the authors discuss the potential benefits, risks and impact of using Ad-derived vaccines to control Ebola virus disease.

Biology and host associations of redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae), exotic vector of laurel wilt killing redbay trees in the Southeastern United States

Treesearch

James L. Hanula; Albert E. Mayfield; Stephen W. Fraedrich; Robert J. Babaglia

2008-01-01

The redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolyhnae), and its fungal symbiont, Rafaelea sp., are new introductions to the southeastern United States responsible for the wilt of mature redbay, Persea borbonia (L) Spreng., trees. In 2006 and 2007, we investigated the...

WORKING WITH ALKALINE MATERIALS TO ACHIEVE A CLASS B, CLASS A, AND/OR A BIOSOLIDS THAT DOES NOT ATTRACT VECTORS

EPA Science Inventory

This workshop presentation begins with a discussion of the use of lime and other alkaline materials from the very earliest times to the present for killing bacteria, viruses and parasites and for controlling odors in wastewaters and sludge. It answers the question "How did EPA ar...

Higher-Order Corrections to Timelike Jets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giele, W.T.; /Fermilab; Kosower, D.A.

2011-02-01

We present a simple formalism for the evolution of timelike jets in which tree-level matrix element corrections can be systematically incorporated, up to arbitrary parton multiplicities and over all of phase space, in a way that exponentiates the matching corrections. The scheme is cast as a shower Markov chain which generates one single unweighted event sample, that can be passed to standard hadronization models. Remaining perturbative uncertainties are estimated by providing several alternative weight sets for the same events, at a relatively modest additional overhead. As an explicit example, we consider Z {yields} q{bar q} evolution with unpolarized, massless quarksmore » and include several formally subleading improvements as well as matching to tree-level matrix elements through {alpha}{sub s}{sup 4}. The resulting algorithm is implemented in the publicly available VINCIA plugin to the PYTHIA8 event generator.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sergyeyev, Artur; Krtous, Pavel; Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University in Prague, V Holesovickach 2, Prague

We consider the Klein-Gordon equation in generalized higher-dimensional Kerr-NUT-(A)dS spacetime without imposing any restrictions on the functional parameters characterizing the metric. We establish commutativity of the second-order operators constructed from the Killing tensors found in [J. High Energy Phys. 02 (2007) 004] and show that these operators, along with the first-order operators originating from the Killing vectors, form a complete set of commuting symmetry operators (i.e., integrals of motion) for the Klein-Gordon equation. Moreover, we demonstrate that the separated solutions of the Klein-Gordon equation obtained in [J. High Energy Phys. 02 (2007) 005] are joint eigenfunctions for all of thesemore » operators. We also present an explicit form of the zero mode for the Klein-Gordon equation with zero mass. In the semiclassical approximation we find that the separated solutions of the Hamilton-Jacobi equation for geodesic motion are also solutions for a set of Hamilton-Jacobi-type equations which correspond to the quadratic conserved quantities arising from the above Killing tensors.« less

Marginally outer trapped surfaces and symmetries

NASA Astrophysics Data System (ADS)

Carrasco, Alberto; Mars, Marc

2009-05-01

We study properties of outermost marginally outer trapped surfaces in slices of space-times possessing certain symmetries, like isometries, homotheties or conformal Killings. In particular, we find restrictions on these surfaces for the vector field generating the symmetry. As an application we give a result of non-existence of outermost marginally outer trapped surfaces in accelerated Friedmann-Lemaître-Roberson-Walker spacetimes.

General minimal surface solution for gravitational instantons

NASA Astrophysics Data System (ADS)

Aliev, A. N.; Kalaycı, J.; Nutku, Y.

1997-07-01

We construct the general instanton metric obtained from Weierstrass' general local solution for minimal surfaces using the correspondence between minimal surfaces in three-dimensional Euclidean space and gravitational instantons admitting two Killing vectors. The resulting metric contains one arbitrary analytic function and we show that it can be transformed to the Gibbons-Hawking form of an instanton metric that was reported earlier.

Does myxomatosis still regulate numbers of rabbits (Oryctolagus cuniculus Linnaeus, 1758) in the United Kingdom?

PubMed

Trout, R C; Ross, J; Fox, A P

1993-03-01

Myxomatosis now kills a much smaller proportion of rabbit populations than in the past, while remaining an important regulatory factor, as shown experimentally. On two separate occasions, experimental reduction of the prevalence of the disease (by reducing infestations of the main vector, the rabbit flea) led to significant increases in numbers of rabbits surviving the winter.

40 CFR 180.1154 - CryIA(c) and CryIC derived delta-endotoxins of Bacillus thuringiensis var. kurstaki encapsulated...

Code of Federal Regulations, 2010 CFR

2010-07-01

...-endotoxins of Bacillus thuringiensis var. kurstaki encapsulated in killed Pseudomonas fluorescens, and the... RESIDUES IN FOOD Exemptions From Tolerances § 180.1154 CryIA(c) and CryIC derived delta-endotoxins of... plasmid and cloning vector genetic constructs. CryIA(c) and CryIC derived delta-endotoxins of Bacillus...

40 CFR 180.1154 - CryIA(c) and CryIC derived delta-endotoxins of Bacillus thuringiensis var. kurstaki encapsulated...

Code of Federal Regulations, 2011 CFR

2011-07-01

...-endotoxins of Bacillus thuringiensis var. kurstaki encapsulated in killed Pseudomonas fluorescens, and the... RESIDUES IN FOOD Exemptions From Tolerances § 180.1154 CryIA(c) and CryIC derived delta-endotoxins of... plasmid and cloning vector genetic constructs. CryIA(c) and CryIC derived delta-endotoxins of Bacillus...

Prallethrin-induced excitation increases contact between sprayed ultra-low-volume droplets and flying mosquitoes (Diptera: Culicidae) in a wind tunnel

USDA-ARS?s Scientific Manuscript database

Mosquitoes are important in the United States due to their roles as pestiferous biters and vectors of diseases such as West Nile Virus and Dengue. Conventional applications of pesticides in spray clouds are often limited by their ability to contact and kill mosquitoes that may be resting or hiding ...

40 CFR 180.1154 - CryIA(c) and CryIC derived delta-endotoxins of Bacillus thuringiensis var. kurstaki encapsulated...

Code of Federal Regulations, 2013 CFR

2013-07-01

...-endotoxins of Bacillus thuringiensis var. kurstaki encapsulated in killed Pseudomonas fluorescens, and the... RESIDUES IN FOOD Exemptions From Tolerances § 180.1154 CryIA(c) and CryIC derived delta-endotoxins of... plasmid and cloning vector genetic constructs. CryIA(c) and CryIC derived delta-endotoxins of Bacillus...

40 CFR 180.1154 - CryIA(c) and CryIC derived delta-endotoxins of Bacillus thuringiensis var. kurstaki encapsulated...

Code of Federal Regulations, 2012 CFR

2012-07-01

...-endotoxins of Bacillus thuringiensis var. kurstaki encapsulated in killed Pseudomonas fluorescens, and the... RESIDUES IN FOOD Exemptions From Tolerances § 180.1154 CryIA(c) and CryIC derived delta-endotoxins of... plasmid and cloning vector genetic constructs. CryIA(c) and CryIC derived delta-endotoxins of Bacillus...

40 CFR 180.1154 - CryIA(c) and CryIC derived delta-endotoxins of Bacillus thuringiensis var. kurstaki encapsulated...

Code of Federal Regulations, 2014 CFR

2014-07-01

...-endotoxins of Bacillus thuringiensis var. kurstaki encapsulated in killed Pseudomonas fluorescens, and the... RESIDUES IN FOOD Exemptions From Tolerances § 180.1154 CryIA(c) and CryIC derived delta-endotoxins of... plasmid and cloning vector genetic constructs. CryIA(c) and CryIC derived delta-endotoxins of Bacillus...

Mutation in the sodium channel gene corresponds with phenotypic resistance of Rhipicephalus sanguineus sensu lato (Acari: Ixodidae) to pyrethroids

USDA-ARS?s Scientific Manuscript database

The brown dog tick, Rhipicephalus sanguineus sensu lato, is a cosmopolitan ectoparasite and vector of pathogens that kill humans and animals. Pyrethroids represent a class of synthetic acaricides that have been used intensely to try to control the brown dog tick and mitigate the risk of tick-borne d...

Eisenhart lifts and symmetries of time-dependent systems

NASA Astrophysics Data System (ADS)

Cariglia, M.; Duval, C.; Gibbons, G. W.; Horváthy, P. A.

2016-10-01

Certain dissipative systems, such as Caldirola and Kannai's damped simple harmonic oscillator, may be modelled by time-dependent Lagrangian and hence time dependent Hamiltonian systems with n degrees of freedom. In this paper we treat these systems, their projective and conformal symmetries as well as their quantisation from the point of view of the Eisenhart lift to a Bargmann spacetime in n + 2 dimensions, equipped with its covariantly constant null Killing vector field. Reparametrisation of the time variable corresponds to conformal rescalings of the Bargmann metric. We show how the Arnold map lifts to Bargmann spacetime. We contrast the greater generality of the Caldirola-Kannai approach with that of Arnold and Bateman. At the level of quantum mechanics, we are able to show how the relevant Schrödinger equation emerges naturally using the techniques of quantum field theory in curved spacetimes, since a covariantly constant null Killing vector field gives rise to well defined one particle Hilbert space. Time-dependent Lagrangians arise naturally also in cosmology and give rise to the phenomenon of Hubble friction. We provide an account of this for Friedmann-Lemaître and Bianchi cosmologies and how it fits in with our previous discussion in the non-relativistic limit.

[Retroviral-mediated transfer of a hygromycin phosphotransferase-thymidine kinase fusion gene into human bladder carcinoma cell].

PubMed

Ye, C; Chen, S; Pei, X; Li, L; Feng, K

1999-08-01

To evaluate the therapeutic efficacy of retroviral-mediated hygromycin phosphotransferase-thymidine kinase fusion gene (HyTK)/GCV on human bladder carcinoma cell. A retroviral expression vector pL (HyTK) SN was constructed. By using FuGENE 6-mediated transfection and "ping-pong effect" technique, high-titer of retroviral supernatant was obtained and HyTK gene was transferred into EJ cells. A retroviral vector encoding, enhanced green fluorescent protein, EGFP was used to rapidly detect the transduction efficiency. Antitumor effects were observed after GCV treatment. In vitro experiments demonstrated the EJ cells transferred by HyTK gene were killed in the GCV treatment. Non-transduced parental cells were not sensitive to GCV, but they were dead by the bystander killing of neighboring cells when mixed with EJ/HyTK cells at various ratios. In addition, this not only affect wild-type EJ cells but also cells from different bladder carcinoma cell lines. Retroviral-mediated HyTK/GCV systems were a promising suicide gene therapy for bladder carcinoma. EGFP may act as a convenient and rapid reporter to monitor retroviral-mediated gene transfer and expression in bladder carcinoma cells.

An Impossible Journey? The Development of Plasmodium falciparum NF54 in Culex quinquefasciatus

PubMed Central

Knöckel, Julia; Molina-Cruz, Alvaro; Fischer, Elizabeth; Muratova, Olga; Haile, Ashley; Barillas-Mury, Carolina; Miller, Louis H.

2013-01-01

Although Anopheles mosquitoes are the vectors for human Plasmodium spp., there are also other mosquito species–among them culicines (Culex spp., Aedes spp.)–present in malaria-endemic areas. Culicine mosquitoes transmit arboviruses and filarial worms to humans and are vectors for avian Plasmodium spp., but have never been observed to transmit human Plasmodium spp. When ingested by a culicine mosquito, parasites could either face an environment that does not allow development due to biologic incompatibility or be actively killed by the mosquito’s immune system. In the latter case, the molecular mechanism of killing must be sufficiently powerful that Plasmodium is not able to overcome it. To investigate how human malaria parasites develop in culicine mosquitoes, we infected Culex quinquefasciatus with Plasmodium falciparum NF54 and monitored development of parasites in the blood bolus and midgut epithelium at different time points. Our results reveal that ookinetes develop in the midgut lumen of C. quinquefasciatus in slightly lower numbers than in Anopheles gambiae G3. After 30 hours, parasites have invaded the midgut and can be observed on the basal side of the midgut epithelium by confocal and transmission electron microscopy. Very few of the parasites in C. quinquefasciatus are alive, most of them are lysed. Eight days after the mosquito’s blood meal, no oocysts can be found in C. quinquefasciatus. Our results suggest that the mosquito immune system could be involved in parasite killing early in development after ookinetes have crossed the midgut epithelium and come in contact with the mosquito hemolymph. PMID:23658824

Apoptin towards safe and efficient anticancer therapies.

PubMed

Backendorf, Claude; Noteborn, Mathieu H M

2014-01-01

The chicken anemia virus derived protein apoptin harbors cancer-selective cell killing characteristics, essentially based on phosphorylation-mediated nuclear transfer in cancer cells and efficient cytoplasmic degradation in normal cells. Here, we describe a growing set of preclinical experiments underlying the promises of the anti-cancer potential of apoptin. Various non-replicative oncolytic viral vector systems have revealed the safety and efficacy of apoptin. In addition, apoptin enhanced the oncolytic potential of adenovirus, parvovirus and Newcastle disease virus vectors. Intratumoral injection of attenuated Salmonella typhimurium bacterial strains and plasmid-based systems expressing apoptin resulted in significant tumor regression. In-vitro and in-vivo experiments showed that recombinant membrane-transferring PTD4- or TAT-apoptin proteins have potential as a future anticancer therapeutics. In xenografted hepatoma and melanoma mouse models PTD4-apoptin protein entered both cancer and normal cells, but only killed cancer cells. Combinatorial treatment of PTD4-apoptin with various (chemo)therapeutic compounds revealed an additive or even synergistic effect, reducing the side effects of the single (chemo)therapeutic treatment. Degradable polymeric nanocapsules harboring MBP-apoptin fusion-protein induced tumor-selective cell killing in-vitro and in-vivo and revealed the potential of polymer-apoptin protein vehicles as an anticancer agent.Besides its direct use as an anticancer therapeutic, apoptin research has also generated novel possibilities for drug design. The nuclear location domains of apoptin are attractive tools for targeting therapeutic compounds into the nucleus of cancer cells. Identification of cancer-related processes targeted by apoptin can potentially generate novel drug targets. Recent breakthroughs important for clinical applications are reported inferring apoptin-based clinical trials as a feasible reality.

Magnetic dipole transitions of Bc and Bc* mesons in the relativistic independent quark model

NASA Astrophysics Data System (ADS)

Patnaik, Sonali; Dash, P. C.; Kar, Susmita; Patra, Sweta P.; Barik, N.

2017-12-01

We study M1-transitions involving mesons: Bc(1 s ), Bc*(1 s ), Bc(2 s ), Bc*(2 s ), Bc(3 s ), and Bc*(3 s ) in the relativistic independent quark (RIQ) model based on a flavor independent average potential in the scalar-vector harmonic form. The transition form factor for Bc*→Bcγ is found to have analytical continuation from spacelike to physical timelike region. Our predicted coupling constant gBc*Bc=0.34 GeV-1 and decay width Γ (Bc*→Bcγ )=23 eV agree with other model predictions. In view of possible observation of Bc and Bc* s-wave states at LHC and Z-factory and potential use of theoretical estimate on M1-transitions, we investigate the allowed as well as hindered transitions of orbitally excited Bc-meson states and predict their decay widths in overall agreement with other model predictions. We consider the typical case of Bc*(1 s )→Bc(1 s )γ , where our predicted decay width which is found quite sensitive to the mass difference between Bc* and Bc mesons may help in determining the mass of Bc* experimentally.

Peripheral transverse densities of the baryon octet from chiral effective field theory and dispersion analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alarcón, J. M.; Hiller Blin, A. N.; Vicente Vacas, M. J.

2017-05-08

The baryon electromagnetic form factors are expressed in terms of two-dimensional densities describing the distribution of charge and magnetization in transverse space at fixed light-front time. In this paper, we calculate the transverse densities of the spin-1/2 flavor-octet baryons at peripheral distances b=O(Mmore » $$-1\\atop{π}$$) using methods of relativistic chiral effective field theory (χ EFT) and dispersion analysis. The densities are represented as dispersive integrals over the imaginary parts of the form factors in the timelike region (spectral functions). The isovector spectral functions on the two-pion cut t > 4 M$$2\\atop{π}$$ are calculated using relativistic χEFT including octet and decuplet baryons. The χEFT calculations are extended into the ρ meson mass region using an N/D method that incorporates the pion electromagnetic form factor data. The isoscalar spectral functions are modeled by vector meson poles. We compute the peripheral charge and magnetization densities in the octet baryon states, estimate the uncertainties, and determine the quark flavor decomposition. Finally, the approach can be extended to baryon form factors of other operators and the moments of generalized parton distributions.« less

Inertial Mass from Spin Nonlinearity

NASA Astrophysics Data System (ADS)

Cohen, Marcus

The inertial mass of a Fermion shows up as chiral cross-coupling in its Dirac system. No scalar term can invariantly couple left and right chirality fields; the Dirac matrices must be spin tensors of mixed chirality. We show how such tensor couplings could arise from nonlinear mixing of four spinor fields, two representing the local electron fields and two inertial spinor fields sourced in the distant masses. We thus give a model that implements Mach's principle. Following Mendel Sachs,1 we let the inertial spinors factor the moving spacetime tetrads qα(x) and bar {q}α (x) that appear in the Dirac operator. The inertial spinors do more than set the spacetime "stage;" they are players in the chiral dynamics. Specifically, we show how the massive Dirac system arises as the envelope modulation equations coupling left and right chirality electron fields on a Friedmann universe via nonlinear "spin gratings" with the inertial spinor fields. These gratings implement Penrose's "mass-scatterings," which keep the null zig-zags of the bispinor wave function confined to a timelike world tube. Local perturbations to the inertial spinor fields appear in the Dirac system as Abelian and non-Abelian vector potentials.

Decay constants and radiative decays of heavy mesons in light-front quark model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Ho-Meoyng

2007-04-01

We investigate the magnetic dipole decays V{yields}P{gamma} of various heavy-flavored mesons such as (D,D*,D{sub s},D{sub s}*,{eta}{sub c},J/{psi}) and (B,B*,B{sub s},B{sub s}*,{eta}{sub b},{upsilon}) using the light-front quark model constrained by the variational principle for the QCD-motivated effective Hamiltonian. The momentum dependent form factors F{sub VP}(q{sup 2}) for V{yields}P{gamma}* decays are obtained in the q{sup +}=0 frame and then analytically continued to the timelike region by changing q{sub perpendicular} to iq{sub perpendicular} in the form factors. The coupling constant g{sub VP{gamma}} for real photon case is then obtained in the limit as q{sup 2}{yields}0, i.e. g{sub VP{gamma}}=F{sub VP}(q{sup 2}=0). The weak decaymore » constants of heavy pseudoscalar and vector mesons are also calculated. Our numerical results for the decay constants and radiative decay widths for the heavy-flavored mesons are overall in good agreement with the available experimental data as well as other theoretical model calculations.« less

What does not kill them makes them stronger: larval environment and infectious dose alter mosquito potential to transmit filarial worms.

PubMed

Breaux, Jennifer A; Schumacher, Molly K; Juliano, Steven A

2014-07-07

For organisms with complex life cycles, larval environments can modify adult phenotypes. For mosquitoes and other vectors, when physiological impacts of stressors acting on larvae carry over into the adult stage they may interact with infectious dose of a vector-borne pathogen, producing a range of phenotypes for vector potential. Investigation of impacts of a common source of stress, larval crowding and intraspecific competition, on adult vector interactions with pathogens may increase our understanding of the dynamics of pathogen transmission by mosquito vectors. Using Aedes aegypti and the nematode parasite Brugia pahangi, we demonstrate dose dependency of fitness effects of B. pahangi infection on the mosquito, as well as interactions between competitive stress among larvae and infectious dose for resulting adults that affect the physiological and functional ability of mosquitoes to act as vectors. Contrary to results from studies on mosquito-arbovirus interactions, our results suggest that adults from crowded larvae may limit infection better than do adults from uncrowded controls, and that mosquitoes from high-quality larval environments are more physiologically and functionally capable vectors of B. pahangi. Our results provide another example of how the larval environment can have profound effects on vector potential of resulting adults. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

A novel biological 'twin-father' temporal paradox of General Relativity in a Gödel universe - Where reproductive biology meets theoretical physics.

PubMed

Ashrafian, Hutan

2018-03-01

Several temporal paradoxes exist in physics. These include General Relativity's grandfather and ontological paradoxes and Special Relativity's Langevin-Einstein twin-paradox. General relativity paradoxes can exist due to a Gödel universe that follows Gödel's closed timelike curves solution to Einstein's field equations. A novel biological temporal paradox of General Relativity is proposed based on reproductive biology's phenomenon of heteropaternal fecundation. Herein, dizygotic twins from two different fathers are the result of concomitant fertilization during one menstrual cycle. In this case an Oedipus-like individual exposed to a Gödel closed timelike curve would sire a child during his maternal fertilization cycle. As a consequence of heteropaternal superfecundation, he would father his own dizygotic twin and would therefore generate a new class of autofraternal superfecundation, and by doing so creating a 'twin-father' temporal paradox. Copyright © 2017 Elsevier Ltd. All rights reserved.

(2+1)-dimensional spacetimes containing closed timelike curves

NASA Astrophysics Data System (ADS)

Headrick, Matthew P.; Gott, J. Richard, III

1994-12-01

We investigate the global geometries of (2+1)-dimensional spacetimes as characterized by the transformations undergone by tangent spaces upon parallel transport around closed curves. We critically discuss the use of the term ``total energy-momentum'' as a label for such parallel-transport transformations, pointing out several problems with it. We then investigate parallel-transport transformations in the known (2+1)-dimensional spacetimes containing closed timelike curves (CTC's), and introduce a few new such spacetimes. Using the more specific concept of the holonomy of a closed curve, applicable in simply connected spacetimes, we emphasize that Gott's two-particle CTC-containing spacetime does not have a tachyonic geometry. Finally, we prove the following modified version of Kabat's conjecture: if a CTC is deformable to spacelike or null infinity while remaining a CTC, then its parallel-transport transformation cannot be a rotation; therefore its holonomy, if defined, cannot be a rotation other than through a multiple of 2π.

Quantum field theory in spaces with closed timelike curves

NASA Astrophysics Data System (ADS)

Boulware, David G.

1992-11-01

Gott spacetime has closed timelike curves, but no locally anomalous stress energy. A complete orthonormal set of eigenfunctions of the wave operator is found in the special case of a spacetime in which the total deficit angle is 2π. A scalar quantum field theory is constructed using these eigenfunctions. The resultant interacting quantum field theory is not unitary because the field operators can create real, on-shell, particles in the noncausal region. These particles propagate for finite proper time accumulating an arbitrary phase before being annihilated at the same spacetime point as that at which they were created. As a result, the effective potential within the noncausal region is complex, and probability is not conserved. The stress tensor of the scalar field is evaluated in the neighborhood of the Cauchy horizon; in the case of a sufficiently small Compton wavelength of the field, the stress tensor is regular and cannot prevent the formation of the Cauchy horizon.

Precision measurements of the timelike electromagnetic form factors of pion, kaon, and proton.

PubMed

Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Gong, D T; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Li, S Z; Poling, R; Scott, A W; Smith, A; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Zweber, P; Ernst, J; Arms, K; Severini, H; Dytman, S A; Love, W; Mehrabyan, S; Mueller, J A; Savinov, V; Li, Z; Lopez, A; Mendez, H; Ramirez, J; Huang, G S; Miller, D H; Pavlunin, V; Sanghi, B; Shipsey, I P J; Adams, G S; Anderson, M; Cummings, J P; Danko, I; Napolitano, J; He, Q; Muramatsu, H; Park, C S; Thorndike, E H; Coan, T E; Gao, Y S; Liu, F; Artuso, M; Boulahouache, C; Blusk, S; Butt, J; Dorjkhaidav, O; Li, J; Menaa, N; Mountain, R; Randrianarivony, K; Redjimi, R; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Zhang, K; Csorna, S E; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Bornheim, A; Pappas, S P; Weinstein, A J; Briere, R A; Chen, G P; Chen, J; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Adam, N E; Alexander, J P; Berkelman, K; Cassel, D G; Duboscq, J E; Ecklund, K M; Ehrlich, R; Fields, L; Galik, R S; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Meyer, T O; Onyisi, P U E; Patterson, J R; Peterson, D; Phillips, E A; Pivarski, J; Riley, D; Ryd, A; Sadoff, A J; Schwarthoff, H; Shi, X; Shepherd, M R; Stroiney, S; Sun, W M; Wilksen, T; Weaver, K M; Weinberger, M; Athar, S B; Avery, P; Breva-Newell, L; Patel, R; Potlia, V; Stoeck, H; Yelton, J; Rubin, P; Cawlfield, C; Eisenstein, B I; Karliner, I; Kim, D; Lowrey, N; Naik, P; Sedlack, C; Selen, M; White, E J; Williams, J; Wiss, J; Asner, D M; Edwards, K W; Besson, D

2005-12-31

Using 20.7 pb(-1) of e(+)e(-) annihilation data taken at sq.rt(r) = 3.671 GeV with the CLEO-c detector, precision measurements of the electromagnetic form factors of the charged pion, charged kaon, and proton have been made for timelike momentum transfer of |Q(2)| = 13.48 GeV(2) by the reaction e(+)e(-) --> h(+)h(-). The measurements are the first ever with identified pions and kaons of |Q(2)| > 4 GeV(2), with the results F(13.48 GeV(2)) = 0.075 +/- 0.008(stat) +/- 0.005(syst) and F(K)(13.48 GeV(2)) = 0.063 +/- 0.004(stat) +/- 0.001(syst). The result for the proton, assuming G(p)(E) = G(p)(M), is G(p)(M)(13.48 GeV(2)) = 0.014 +/- 0.002(stat) +/- 0.001(syst), which is in agreement with earlier results.

Extraction of Generalized Parton Distributions from combined Deeply Virtual Compton Scattering and Timelike Compton scattering fits

NASA Astrophysics Data System (ADS)

Boer, Marie

2017-09-01

Generalized Parton Distributions (GPDs) contain the correlation between the parton's longitudinal momentum and their transverse distribution. They are accessed through hard exclusive processes, such as Deeply Virtual Compton Scattering (DVCS). DVCS has already been measured in several experiments and several models allow for extracting GPDs from these measurements. Timelike Compton Scattering (TCS) is, at leading order, the time-reversal equivalent process to DVCS and accesses GPDs at the same kinematics. Comparing GPDs extracted from DVCS and TCS is a unique way for proving GPD universality. Combining fits from the two processes will also allow for better constraining the GPDs. We will present our method for extracting GPDs from DVCS and TCS pseudo-data. We will compare fit results from the two processes in similar conditions and present what can be expected in term of contraints on GPDs from combined fits.

Closed Timelike Loops in Homogeneous Rotating Λ-dust Cosmologies

NASA Astrophysics Data System (ADS)

Lindsay, David

2015-04-01

We first describes what a ``rotating'' Λ-dust universe is in general relativity: basically, our universe plus a small amount of rotation. We then mention the Canonical example, the Gödel solution, which would add one rotation to our universe in about 200 billion years. Then we describe what we believe to be all known homogeneous rotating Λ-dust cosmologies. A plot of their characteristics shows that they cannot comprise all such solutions, though the literature claims (in several places) that all rotating solutions with a non-zero Λ term have been discovered. Our research has investigated these solutions for closed timelike loops (CTLs), i.e., time-machines, and concluded that exactly those with Λ < 0 possess CTLs. This observation calls into question the standard bias in GR that ``too much'' rotation leads to non-causal behavior; instead, it appears that a negative cosmological constant is the culprit.

Inhalation of Nebulized Perfluorochemical Enhances Recombinant Adenovirus and Adeno-Associated Virus-Mediated Gene Expression in Lung Epithelium

PubMed Central

Beckett, Travis; Bonneau, Laura; Howard, Alan; Blanchard, James; Borda, Juan; Weiner, Daniel J.; Wang, Lili; Gao, Guang Ping; Kolls, Jay K.; Bohm, Rudolf; Liggitt, Denny

2012-01-01

Abstract Use of perfluorochemical liquids during intratracheal vector administration enhances recombinant adenovirus and adeno-associated virus (AAV)-mediated lung epithelial gene expression. We hypothesized that inhalation of nebulized perfluorochemical vapor would also enhance epithelial gene expression after subsequent intratracheal vector administration. Freely breathing adult C57BL/6 mice were exposed for selected times to nebulized perflubron or sterile saline in a sealed Plexiglas chamber. Recombinant adenoviral vector was administered by transtracheal puncture at selected times afterward and mice were killed 3 days after vector administration to assess transgene expression. Mice tolerated the nebulized perflubron without obvious ill effects. Vector administration 6 hr after nebulized perflubron exposure resulted in an average 540% increase in gene expression in airway and alveolar epithelium, compared with that with vector alone or saline plus vector control (p<0.05). However, vector administration 1 hr, 1 day, or 3 days after perflubron exposure was not different from either nebulized saline with vector or vector alone and a 60-min exposure to nebulized perflubron is required. In parallel pilot studies in macaques, inhalation of nebulized perflubron enhanced recombinant AAV2/5 vector expression throughout the lung. Serial chest radiographs, bronchoalveolar lavages, and results of complete blood counts and serum biochemistries demonstrated no obvious adverse effects of nebulized perflubron. Further, one macaque receiving nebulized perflubron only was monitored for 1 year with no obvious adverse effects of exposure. These results demonstrate that inhalation of nebulized perflubron, a simple, clinically more feasible technique than intratracheal administration of liquid perflubron, safely enhances lung gene expression. PMID:22568624

Molecular Detection of Breast Cancer

DTIC Science & Technology

1998-02-01

treatment-resistant cancer cells. Clearly new approaches are needed to treat these diseases. This project is designed to develop novel approaches to...detect breast cancer cells that contaminate peripheral blood and bone marrow, and to remove such contaminating cells. An RT-PCR assay has been developed ...to detect breast cancer cells, and a novel gene therapy vector has been developed to kill contaminating cancer cells. Blood and bone marrow samples

Japanese oak wilt as a newly emerged forest pest in Japan: why does a symbiotic ambrosia fungus kill host trees?

Treesearch

Naoto Kamata; Koujiro Esaki; Kenryu Kato; Hisahito Oana; Yutaka Igeta; Ryotaro Komura

2007-01-01

Japanese oak wilt (JOW) has been known since the 1930s, but in the last 15 years epidemics have intensified and spread to the island's western coastal areas. The symbiotic ambrosia fungus Raffaelea quercivora is the causal agent of oak dieback, and is vectored by Platypus quercivorus (Murayama). This is the first example of an...

A Safe Bacterial Microsyringe for In Vivo Antigen Delivery and Immunotherapy

PubMed Central

Le Gouëllec, Audrey; Chauchet, Xavier; Laurin, David; Aspord, Caroline; Verove, Julien; Wang, Yan; Genestet, Charlotte; Trocme, Candice; Ahmadi, Mitra; Martin, Sandrine; Broisat, Alexis; Cretin, François; Ghezzi, Catherine; Polack, Benoit; Plumas, Joël; Toussaint, Bertrand

2013-01-01

The industrial development of active immunotherapy based on live-attenuated bacterial vectors has matured. We developed a microsyringe for antigen delivery based on the type III secretion system (T3SS) of P. aeruginosa. We applied the “killed but metabolically active” (KBMA) attenuation strategy to make this bacterial vector suitable for human use. We demonstrate that attenuated P. aeruginosa has the potential to deliver antigens to human antigen-presenting cells in vitro via T3SS with considerable attenuated cytotoxicity as compared with the wild-type vector. In a mouse model of cancer, we demonstrate that this KBMA strain, which cannot replicate in its host, efficiently disseminates into lymphoid organs and delivers its heterologous antigen. The attenuated strain effectively induces a cellular immune response to the cancerous cells while lowering the systemic inflammatory response. Hence, a KBMA P. aeruginosa microsyringe is an efficient and safe tool for in vivo antigen delivery. PMID:23531551

[Construction, expression and characterization of the fusion gene of super-antigen SEA and single chain Fv of the ND-1 monoclonal antibody against human colorectal cancer].

PubMed

Chen, Hang; Li, Li; Fang, Jin

2012-04-01

To construct and express the recombinant ND-1-scFv/SEA, a fusion protein of superantigen (staphylococcal enterotoxinA, SEA) and single-chain variable fragment of monoclonal antibody ND-1 against human clolorectal carcinoma, and to enhance the targeted killing effect of SEA. The expression of the fusion protein was induced in E.coli M15 by IPTG. Ni-NTA resin affinity chromatography was used to separate and purify the expressed product. The specific binding activity of the purified ND-1-scFv/SEA protein was examined by indirect immunofluorescence assay and the targeted-cytotoxicity was determined using MTT assay. The expressing vector of fusion gene ND-1scFv/SEA was constructed successfully. ND-1-scFv/SEA protein retained a high binding affinity to antigen-positive human colorectal cancer cell CCL-187 and had a stronger capability to activate PBMC and kill the target cells compared to SEA alone, with a killing rate of 91% at 4 μg/mL. ND-1-scFv/SEA fusion protein could specifically target colorectal cancer cell, enhance the activity of kill tumor cell and has potential applications in the targeted therapy of colorectal cancer.

Oviposition Site Selection by the Dengue Vector Aedes aegypti and Its Implications for Dengue Control

PubMed Central

Wong, Jacklyn; Stoddard, Steven T.; Astete, Helvio; Morrison, Amy C.; Scott, Thomas W.

2011-01-01

Background Because no dengue vaccine or antiviral therapy is commercially available, controlling the primary mosquito vector, Aedes aegypti, is currently the only means to prevent dengue outbreaks. Traditional models of Ae. aegypti assume that population dynamics are regulated by density-dependent larval competition for food and little affected by oviposition behavior. Due to direct impacts on offspring survival and development, however, mosquito choice in oviposition site can have important consequences for population regulation that should be taken into account when designing vector control programs. Methodology/Principal Findings We examined oviposition patterns by Ae. aegypti among 591 naturally occurring containers and a set of experimental containers in Iquitos, Peru. Using larval starvation bioassays as an indirect measure of container food content, we assessed whether females select containers with the most food for their offspring. Our data indicate that choice of egg-laying site is influenced by conspecific larvae and pupae, container fill method, container size, lid, and sun exposure. Although larval food positively influenced oviposition, our results did not support the hypothesis that females act primarily to maximize food for larvae. Females were most strongly attracted to sites containing immature conspecifics, even when potential competitors for their progeny were present in abundance. Conclusion/Significance Due to strong conspecific attraction, egg-laying behavior may contribute more to regulating Ae. aegypti populations than previously thought. If highly infested containers are targeted for removal or larvicide application, females that would have preferentially oviposited in those sites may instead distribute their eggs among other suitable, previously unoccupied containers. Strategies that kill mosquitoes late in their development (i.e., insect growth regulators that kill pupae rather than larvae) will enhance vector control by creating “egg sinks,” treated sites that exploit conspecific attraction of ovipositing females, but reduce emergence of adult mosquitoes via density-dependent larval competition and late acting insecticide. PMID:21532736

Synergy between repellents and organophosphates on bed nets: efficacy and behavioural response of natural free-flying An. gambiae mosquitoes.

PubMed

Pennetier, Cédric; Costantini, Carlo; Corbel, Vincent; Licciardi, Séverine; Dabiré, Roch K; Lapied, Bruno; Chandre, Fabrice; Hougard, Jean-Marc

2009-11-19

Chemicals are used on bed nets in order to prevent infected bites and to kill aggressive malaria vectors. Because pyrethroid resistance has become widespread in the main malaria vectors, research for alternative active ingredients becomes urgent. Mixing a repellent and a non-pyrethroid insecticide seemed to be a promising tool as mixtures in the laboratory showed the same features as pyrethroids. We present here the results of two trials run against free-flying Anopheles gambiae populations comparing the effects of two insect repellents (either DEET or KBR 3023, also known as icaridin) and an organophosphate insecticide at low-doses (pirimiphos-methyl, PM) used alone and in combination on bed nets. We showed that mixtures of PM and the repellents induced higher exophily, blood feeding inhibition and mortality among wild susceptible and resistant malaria vectors than compounds used alone. Nevertheless the synergistic interactions are only involved in the high mortality induced by the two mixtures. These field trials argue in favour of the strategy of mixing repellent and organophosphate on bed nets to better control resistant malaria vectors.

A new concept of wormholes and the Multiverse

NASA Astrophysics Data System (ADS)

Novikov, I. D.

2018-03-01

We review a new concept of wormholes. We classify the wormholes into three categories: static, space-like, and time-like, and discuss the properties of each category. The relation between wormholes and black holes is examined. The astrophysical properties of wormholes are investigated.

Host preference of the vector beetle, host resistance, and expanding patterns of Japanese oak wilt in a stand

Treesearch

Kazuyoshi Futai; Hiroaki Kiku; Hong-ye Qi; Hagus Tarn; Yuko Takeuchi; Michimasa Yamasaki

2012-01-01

Since the early 1980s, an epidemic forest disease, Japanese Oak Wilt (JOW), has been spreading from coastal areas along the Sea of Japan to the interior of Honshu island and has been devastating huge areas of forests by killing an enormous number of oak trees in urban fringe mountains, gardens, and parks. The disease is caused by a fungus, Raffaelea...

Field tests on the residual effectiveness of deposits of malathion and Bayer 29493 against resistant Anopheles albimanus in El Salvador*

PubMed Central

Schoof, H. F.; Mathis, Willis; Austin, J. R.

1961-01-01

The appearance of resistance to both dieldrin and DDT in several malaria vectors has intensified investigations on the potential of organophosphorus compounds for residual application. This report describes the final year's activities of a three-year study on malathion. Water-wettable formulations of malathion and of Bayer 29493 were evaluated against DDT/dieldrin-resistant Anopheles albimanus in El Salvador. The results indicate that neither compound at a dosage of 0.5 g/m2 offers any promise as a residual agent. At dosages of 1.0 g/m2 or 2.0 g/m2 the two toxicants gave effective kills (70%-100%) for periods of 21/2-3 months, based on 1-hour exposure to the treated surfaces. Up to 3 months, both compounds gave similar levels of effectiveness on wood, thatch, and mud. On whitewash and plaster surfaces, Bayer 29493 was superior to malathion. The findings indicate that each insecticide has considerable potential value for residual treatment in areas where the malaria vector cannot be killed effectively by either DDT or dieldrin. In such areas, further investigation into their utility as replacements for the chlorinated hydrocarbon insecticides is warranted. ImagesFIG. 1FIG. 2FIG. 3FIG. 4FIG. 5 PMID:13748489

Severe acute respiratory syndrome vaccine efficacy in ferrets: whole killed virus and adenovirus-vectored vaccines.

PubMed

See, Raymond H; Petric, Martin; Lawrence, David J; Mok, Catherine P Y; Rowe, Thomas; Zitzow, Lois A; Karunakaran, Karuna P; Voss, Thomas G; Brunham, Robert C; Gauldie, Jack; Finlay, B Brett; Roper, Rachel L

2008-09-01

Although the 2003 severe acute respiratory syndrome (SARS) outbreak was controlled, repeated transmission of SARS coronavirus (CoV) over several years makes the development of a SARS vaccine desirable. We performed a comparative evaluation of two SARS vaccines for their ability to protect against live SARS-CoV intranasal challenge in ferrets. Both the whole killed SARS-CoV vaccine (with and without alum) and adenovirus-based vectors encoding the nucleocapsid (N) and spike (S) protein induced neutralizing antibody responses and reduced viral replication and shedding in the upper respiratory tract and progression of virus to the lower respiratory tract. The vaccines also diminished haemorrhage in the thymus and reduced the severity and extent of pneumonia and damage to lung epithelium. However, despite high neutralizing antibody titres, protection was incomplete for all vaccine preparations and administration routes. Our data suggest that a combination of vaccine strategies may be required for effective protection from this pathogen. The ferret may be a good model for SARS-CoV infection because it is the only model that replicates the fever seen in human patients, as well as replicating other SARS disease features including infection by the respiratory route, clinical signs, viral replication in upper and lower respiratory tract and lung damage.

Antitumor activity of cytotoxic T lymphocytes engineered to target vascular endothelial growth factor receptors

NASA Astrophysics Data System (ADS)

Niederman, Thomas M. J.; Ghogawala, Zoher; Carter, Bob S.; Tompkins, Hillary S.; Russell, Margaret M.; Mulligan, Richard C.

2002-05-01

The demonstration that angiogenesis is required for the growth of solid tumors has fueled an intense interest in the development of new therapeutic strategies that target the tumor vasculature. Here we report the development of an immune-based antiangiogenic strategy that is based on the generation of T lymphocytes that possess a killing specificity for cells expressing vascular endothelial growth factor receptors (VEGFRs). To target VEGFR-expressing cells, recombinant retroviral vectors were generated that encoded a chimeric T cell receptor comprised of VEGF sequences linked to intracellular signaling sequences derived from the chain of the T cell receptor. After transduction of primary murine CD8 lymphocytes by such vectors, the transduced cells were shown to possess an efficient killing specificity for cells expressing the VEGF receptor, Flk-1, as measured by in vitro cytotoxicity assays. After adoptive transfer into tumor-bearing mice, the genetically modified cytotoxic T lymphocytes strongly inhibited the growth of a variety of syngeneic murine tumors and human tumor xenografts. An increased effect on in vivo tumor growth inhibition was seen when this therapy was combined with the systemic administration of TNP-470, a conventional angiogenesis inhibitor. The utilization of the immune system to target angiogenic markers expressed on tumor vasculature may prove to be a powerful means for controlling tumor growth.

Photoacoustically-guided photothermal killing of mosquitoes targeted by nanoparticles.

PubMed

Foster, Stephen R; Galanzha, Ekaterina I; Totten, Daniel C; Beneš, Helen; Shmookler Reis, Robert J; Zharov, Vladimir P

2014-07-01

In biomedical applications, nanoparticles have demonstrated the potential to eradicate abnormal cells in small localized pathological zones associated with cancer or infections. Here, we introduce a method for nanotechnology-based photothermal (PT) killing of whole organisms considered harmful to humans or the environment. We demonstrate that laser-induced thermal, and accompanying nano- and microbubble phenomena, can injure or kill C. elegans and mosquitoes fed carbon nanotubes, gold nanospheres, gold nanoshells, or magnetic nanoparticles at laser energies that are safe for humans. In addition, a photoacoustic (PA) effect was used to control nanoparticle delivery. Through the integration of this technique with molecular targeting, nanoparticle clustering, magnetic capturing and spectral sharpening of PA and PT plasmonic resonances, our laser-based PA-PT nano-theranostic platform can be applied to detection and the physical destruction of small organisms and carriers of pathogens, such as malaria vectors, spiders, bed bugs, fleas, ants, locusts, grasshoppers, phytophagous mites, or other arthropod pests, irrespective of their resistance to conventional treatments. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Quantum field theory in spaces with closed time-like curves

NASA Astrophysics Data System (ADS)

Boulware, D. G.

Gott spacetime has closed timelike curves, but no locally anomalous stress-energy. A complete orthonormal set of eigenfunctions of the wave operator is found in the special case of a spacetime in which the total deficit angle is 27(pi). A scalar quantum field theory is constructed using these eigenfunctions. The resultant interacting quantum field theory is not unitary because the field operators can create real, on-shell, particles in the acausal region. These particles propagate for finite proper time accumulating an arbitrary phase before being annihilated at the same spacetime point as that at which they were created. As a result, the effective potential within the acausal region is complex, and probability is not conserved. The stress tensor of the scalar field is evaluated in the neighborhood of the Cauchy horizon; in the case of a sufficiently small Compton wavelength of the field, the stress tensor is regular and cannot prevent the formation of the Cauchy horizon.

On Closed Timelike Curves and Warped Brane World Models

NASA Astrophysics Data System (ADS)

Slagter, Reinoud Jan

2013-09-01

At first glance, it seems possible to construct in general relativity theory causality violating solutions. The most striking one is the Gott spacetime. Two cosmic strings, approaching each other with high velocity, could produce closed timelike curves. It was quickly recognized that this solution violates physical boundary conditions. The effective one particle generator becomes hyperbolic, so the center of mass is tachyonic. On a 5-dimensional warped spacetime, it seems possible to get an elliptic generator, so no obstruction is encountered and the velocity of the center of mass of the effective particle has an overlap with the Gott region. So a CTC could, in principle, be constructed. However, from the effective 4D field equations on the brane, which are influenced by the projection of the bulk Weyl tensor on the brane, it follows that no asymptotic conical space time is found, so no angle deficit as in the 4D counterpart model. This could also explain why we do not observe cosmic strings.

Is a time symmetric interpretation of quantum theory possible without retrocausality?

NASA Astrophysics Data System (ADS)

Leifer, Matthew S.; Pusey, Matthew F.

2017-06-01

Huw Price has proposed an argument that suggests a time symmetric ontology for quantum theory must necessarily be retrocausal, i.e. it must involve influences that travel backwards in time. One of Price's assumptions is that the quantum state is a state of reality. However, one of the reasons for exploring retrocausality is that it offers the potential for evading the consequences of no-go theorems, including recent proofs of the reality of the quantum state. Here, we show that this assumption can be replaced by a different assumption, called λ-mediation, that plausibly holds independently of the status of the quantum state. We also reformulate the other assumptions behind the argument to place them in a more general framework and pin down the notion of time symmetry involved more precisely. We show that our assumptions imply a timelike analogue of Bell's local causality criterion and, in doing so, give a new interpretation of timelike violations of Bell inequalities. Namely, they show the impossibility of a (non-retrocausal) time symmetric ontology.

Rindler fluid with weak momentum relaxation

NASA Astrophysics Data System (ADS)

Khimphun, Sunly; Lee, Bum-Hoon; Park, Chanyong; Zhang, Yun-Long

2018-01-01

We realize the weak momentum relaxation in Rindler fluid, which lives on the time-like cutoff surface in an accelerating frame of flat spacetime. The translational invariance is broken by massless scalar fields with weak strength. Both of the Ward identity and the momentum relaxation rate of Rindler fluid are obtained, with higher order correction in terms of the strength of momentum relaxation. The Rindler fluid with momentum relaxation could also be approached through the near horizon limit of cutoff AdS fluid with momentum relaxation, which lives on a finite time-like cutoff surface in Anti-de Sitter(AdS) spacetime, and further could be connected with the holographic conformal fluid living on AdS boundary at infinity. Thus, in the holographic Wilson renormalization group flow of the fluid/gravity correspondence with momentum relaxation, the Rindler fluid can be considered as the Infrared Radiation(IR) fixed point, and the holographic conformal fluid plays the role of the ultraviolet(UV) fixed point.

Quantum correlations with no causal order

PubMed Central

Oreshkov, Ognyan; Costa, Fabio; Brukner, Časlav

2012-01-01

The idea that events obey a definite causal order is deeply rooted in our understanding of the world and at the basis of the very notion of time. But where does causal order come from, and is it a necessary property of nature? Here, we address these questions from the standpoint of quantum mechanics in a new framework for multipartite correlations that does not assume a pre-defined global causal structure but only the validity of quantum mechanics locally. All known situations that respect causal order, including space-like and time-like separated experiments, are captured by this framework in a unified way. Surprisingly, we find correlations that cannot be understood in terms of definite causal order. These correlations violate a 'causal inequality' that is satisfied by all space-like and time-like correlations. We further show that in a classical limit causal order always arises, which suggests that space-time may emerge from a more fundamental structure in a quantum-to-classical transition. PMID:23033068

Giant wormholes in ghost-free bigravity theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sushkov, Sergey V.; Volkov, Mikhail S., E-mail: sergey_sushkov@mail.ru, E-mail: volkov@lmpt.univ-tours.fr

2015-06-01

We study Lorentzian wormholes in the ghost-free bigravity theory described by two metrics, g and f. Wormholes can exist if only the null energy condition is violated, which happens naturally in the bigravity theory since the graviton energy-momentum tensors do not apriori fulfill any energy conditions. As a result, the field equations admit solutions describing wormholes whose throat size is typically of the order of the inverse graviton mass. Hence, they are as large as the universe, so that in principle we might all live in a giant wormhole. The wormholes can be of two different types that we callmore » W1 and W2. The W1 wormholes interpolate between the AdS spaces and have Killing horizons shielding the throat. The Fierz-Pauli graviton mass for these solutions becomes imaginary in the AdS zone, hence the gravitons behave as tachyons, but since the Breitenlohner-Freedman bound is fulfilled, there should be no tachyon instability. For the W2 wormholes the g-geometry is globally regular and in the far field zone it becomes the AdS up to subleading terms, its throat can be traversed by timelike geodesics, while the f-geometry has a completely different structure and is not geodesically complete. There is no evidence of tachyons for these solutions, although a detailed stability analysis remains an open issue. It is possible that the solutions may admit a holographic interpretation.« less

Giant wormholes in ghost-free bigravity theory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sushkov, Sergey V.; Volkov, Mikhail S.; Laboratoire de Mathématiques et Physique Théorique CNRS-UMR 7350, Université de Tours, Parc de Grandmont, 37200 Tours

2015-06-09

We study Lorentzian wormholes in the ghost-free bigravity theory described by two metrics, g and f. Wormholes can exist if only the null energy condition is violated, which happens naturally in the bigravity theory since the graviton energy-momentum tensors do not apriori fulfill any energy conditions. As a result, the field equations admit solutions describing wormholes whose throat size is typically of the order of the inverse graviton mass. Hence, they are as large as the universe, so that in principle we might all live in a giant wormhole. The wormholes can be of two different types that we callmore » W1 and W2. The W1 wormholes interpolate between the AdS spaces and have Killing horizons shielding the throat. The Fierz-Pauli graviton mass for these solutions becomes imaginary in the AdS zone, hence the gravitons behave as tachyons, but since the Breitenlohner-Freedman bound is fulfilled, there should be no tachyon instability. For the W2 wormholes the g-geometry is globally regular and in the far field zone it becomes the AdS up to subleading terms, its throat can be traversed by timelike geodesics, while the f-geometry has a completely different structure and is not geodesically complete. There is no evidence of tachyons for these solutions, although a detailed stability analysis remains an open issue. It is possible that the solutions may admit a holographic interpretation.« less

Universal properties of the near-horizon optical geometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gibbons, G. W.; Warnick, C. M.

2009-03-15

Making use of the fact that the optical geometry near a static nondegenerate Killing horizon is asymptotically hyperbolic, we investigate some universal features of black-hole horizons. Applying the Gauss-Bonnet theorem allows us to establish some general properties of gravitational lensing, valid for all black holes. Hyperbolic geometry allows us to find rates for the loss of scalar, vector, and fermionic ''hair'' as objects fall quasistatically towards the horizon, extending previous results for Schwarzschild to all static Killing horizons. In the process we find the Lienard-Wiechert potential for hyperbolic space and calculate the force between electrons mediated by neutrinos, extending themore » flat space result of Feinberg and Sucher. We further demonstrate how these techniques allow us to derive the exact Copson-Linet potential due to a point charge in a Schwarzschild background in a simple fashion.« less

Antipathogen genes and the replacement of disease-vectoring mosquito populations: a model-based evaluation

PubMed Central

Robert, Michael A; Okamoto, Kenichi W; Gould, Fred; Lloyd, Alun L

2014-01-01

Recently, genetic strategies aimed at controlling populations of disease-vectoring mosquitoes have received considerable attention as alternatives to traditional measures. Theoretical studies have shown that female-killing (FK), antipathogen (AP), and reduce and replace (R&R) strategies can each decrease the number competent vectors. In this study, we utilize a mathematical model to evaluate impacts on competent Aedes aegypti populations of FK, AP, and R&R releases as well as hybrid strategies that result from combinations of these three approaches. We show that while the ordering of efficacy of these strategies depends upon population life history parameters, sex ratio of releases, and switch time in combination strategies, AP-only and R&R/AP releases typically lead to the greatest long-term reduction in competent vectors. R&R-only releases are often less effective at long-term reduction of competent vectors than AP-only releases or R&R/AP releases. Furthermore, the reduction in competent vectors caused by AP-only releases is easier to maintain than that caused by FK-only or R&R-only releases even when the AP gene confers a fitness cost. We discuss the roles that density dependence and inclusion of females play in the order of efficacy of the strategies. We anticipate that our results will provide added impetus to continue developing AP strategies. PMID:25558284

Purely electromagnetic spacetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ivanov, B. V.

The Rainich's program of describing metrics induced by pure electromagnetic fields is implemented in a simpler way by using the Ernst formalism and increasing the symmetry of spacetime. Stationary metrics possessing one, two or three Killing vectors are studied and classified. Three branches of solutions exist. Electromagnetically induced mass terms appear in two of them, including a class of solutions in harmonic functions. The static subcase is discussed too. Relations to other well-known electrovacuum metrics are elucidated.

Four-qubit entanglement classification from string theory.

PubMed

Borsten, L; Dahanayake, D; Duff, M J; Marrani, A; Rubens, W

2010-09-03

We invoke the black-hole-qubit correspondence to derive the classification of four-qubit entanglement. The U-duality orbits resulting from timelike reduction of string theory from D=4 to D=3 yield 31 entanglement families, which reduce to nine up to permutation of the four qubits.

Spectra of Lorentz-violating Dirac bound states in a cylindrical well

NASA Astrophysics Data System (ADS)

Xiao, Zhi

2016-12-01

In the presence of the Lorentz-violating bμ coefficient, the spectra of bound states for a Dirac particle in a cylindric well are changed. Compared to the Lorentz invariant (LI) spectrum, the Lorentz violation deviation becomes significant when eigenenergy E is sufficiently close to the critical values ±m , where m is the particle's mass. The detailed profile of the deviation depends on the observer Lorentz nature of bμ. We discussed three types of bμ configuration. When bμ=(0 ,0 ,0 ,bZ) is parallel to the well axis, the would be degenerate LI spectra split into two subspectra, reminiscent of the Zeeman splitting in the presence of a weak magnetic field. Depending on the relative sign of bZ accompanying mass m in the dispersion relation, the spectrum extends or shrinks in the allowed eigenenergy region. When bμ is a radial [bμ=(0 ,b cos ϕ ,b sin ϕ ,0 ) ] or purely timelike vector [bμ=(bT,0 →)], the spin-up and down components are coupled together, and there is no splitting. However, the monotonic increasing behavior of well depth V0 with the decrease of eigenenergy E is slightly changed when E is sufficiently close to -m .

Search for sterile neutrinos decaying into pions at the LHC

NASA Astrophysics Data System (ADS)

Dib, Claudio O.; Kim, C. S.; Neill, Nicolás A.; Yuan, Xing-Bo

2018-02-01

We study the possibility to observe sterile neutrinos with masses in the range 5 GeV

Einstein-Cartan Theory of Gravitation: Kinematical Parameters and Maxwell Equations

NASA Astrophysics Data System (ADS)

Katkar, L. N.

2015-03-01

In the space-time manifold of Einstein-Cartan Theory (ECT) of gravitation, the expressions for the time-like kinematical parameters are derived and the propagation equation for expansion is obtained.It has been observed that when the spin tensor is u-orthogonal the spin of the gravitating matter has no influence on the propagation equation of expansion while it has influence when it is not u-orthogonal. The usual formula for the curl of gradient of a scalar function is not zero in ECT. So is the case with the divergence of the curl of a vector.Their expressions on the space-time manifold of ECT are derived. A new derivative operator d ∗ is introduced to develop the calculus on space-time manifold of ECT. It is obtained by taking the covariant derivative of an associated tensor of a form with respect to an asymmetric connections. We have used this differential operator to obtain the form of the Maxwell's equations in the ECT of gravitation. Cartan's equations of structure are also derived through the new derivative operator. It has been shown that unlike the consequences of exterior derivative in Einstein space-time, the repetition of d ∗ on a form of any degree is not zero.

Refined human artificial chromosome vectors for gene therapy and animal transgenesis

PubMed Central

Kazuki, Y; Hoshiya, H; Takiguchi, M; Abe, S; Iida, Y; Osaki, M; Katoh, M; Hiratsuka, M; Shirayoshi, Y; Hiramatsu, K; Ueno, E; Kajitani, N; Yoshino, T; Kazuki, K; Ishihara, C; Takehara, S; Tsuji, S; Ejima, F; Toyoda, A; Sakaki, Y; Larionov, V; Kouprina, N; Oshimura, M

2011-01-01

Human artificial chromosomes (HACs) have several advantages as gene therapy vectors, including stable episomal maintenance, and the ability to carry large gene inserts. We previously developed HAC vectors from the normal human chromosomes using a chromosome engineering technique. However, endogenous genes were remained in these HACs, limiting their therapeutic applications. In this study, we refined a HAC vector without endogenous genes from human chromosome 21 in homologous recombination-proficient chicken DT40 cells. The HAC was physically characterized using a transformation-associated recombination (TAR) cloning strategy followed by sequencing of TAR-bacterial artificial chromosome clones. No endogenous genes were remained in the HAC. We demonstrated that any desired gene can be cloned into the HAC using the Cre-loxP system in Chinese hamster ovary cells, or a homologous recombination system in DT40 cells. The HAC can be efficiently transferred to other type of cells including mouse ES cells via microcell-mediated chromosome transfer. The transferred HAC was stably maintained in vitro and in vivo. Furthermore, tumor cells containing a HAC carrying the suicide gene, herpes simplex virus thymidine kinase (HSV-TK), were selectively killed by ganciclovir in vitro and in vivo. Thus, this novel HAC vector may be useful not only for gene and cell therapy, but also for animal transgenesis. PMID:21085194

The Effects of Climate Change and Globalization on Mosquito Vectors: Evidence from Jeju Island, South Korea on the Potential for Asian Tiger Mosquito (Aedes albopictus) Influxes and Survival from Vietnam Rather Than Japan

PubMed Central

Jeong, Ji Yeon; Yoo, Seung Jin; Koh, Young-Sang; Lee, Seogjae; Heo, Sang Taek; Seong, Seung-Yong; Lee, Keun Hwa

2013-01-01

Background Climate change affects the survival and transmission of arthropod vectors as well as the development rates of vector-borne pathogens. Increased international travel is also an important factor in the spread of vector-borne diseases (VBDs) such as dengue, West Nile, yellow fever, chikungunya, and malaria. Dengue is the most important vector-borne viral disease. An estimated 2.5 billion people are at risk of infection in the world and there are approximately 50 million dengue infections and an estimated 500,000 individuals are hospitalized with dengue haemorrhagic fever annually. The Asian tiger mosquito (Aedes albopictus) is one of the vectors of dengue virus, and populations already exist on Jeju Island, South Korea. Currently, colder winter temperatures kill off Asian tiger mosquito populations and there is no evidence of the mosquitos being vectors for the dengue virus in this location. However, dengue virus-bearing mosquito vectors can inflow to Jeju Island from endemic area such as Vietnam by increased international travel, and this mosquito vector's survival during colder winter months will likely occur due to the effects of climate change. Methods and Results In this section, we show the geographical distribution of medically important mosquito vectors such as Ae. albopictus, a vector of both dengue and chikungunya viruses; Culex pipiens, a vector of West Nile virus; and Anopheles sinensis, a vector of Plasmodium vivax, within Jeju Island, South Korea. We found a significant association between the mean temperature, amount of precipitation, and density of mosquitoes. The phylogenetic analyses show that an Ae. albopictus, collected in southern area of Jeju Island, was identical to specimens found in Ho Chi Minh, Vietnam, and not Nagasaki, Japan. Conclusion Our results suggest that mosquito vectors or virus-bearing vectors can transmit from epidemic regions of Southeast Asia to Jeju Island and can survive during colder winter months. Therefore, Jeju Island is no longer safe from vector borne diseases (VBDs) due to the effects of globalization and climate change, and we should immediately monitor regional climate change to identify newly emerging VBDs. PMID:23894312

The effects of climate change and globalization on mosquito vectors: evidence from Jeju Island, South Korea on the potential for Asian tiger mosquito (Aedes albopictus) influxes and survival from Vietnam rather than Japan.

PubMed

Lee, Su Hyun; Nam, Kwang Woo; Jeong, Ji Yeon; Yoo, Seung Jin; Koh, Young-Sang; Lee, Seogjae; Heo, Sang Taek; Seong, Seung-Yong; Lee, Keun Hwa

2013-01-01

Climate change affects the survival and transmission of arthropod vectors as well as the development rates of vector-borne pathogens. Increased international travel is also an important factor in the spread of vector-borne diseases (VBDs) such as dengue, West Nile, yellow fever, chikungunya, and malaria. Dengue is the most important vector-borne viral disease. An estimated 2.5 billion people are at risk of infection in the world and there are approximately 50 million dengue infections and an estimated 500,000 individuals are hospitalized with dengue haemorrhagic fever annually. The Asian tiger mosquito (Aedes albopictus) is one of the vectors of dengue virus, and populations already exist on Jeju Island, South Korea. Currently, colder winter temperatures kill off Asian tiger mosquito populations and there is no evidence of the mosquitos being vectors for the dengue virus in this location. However, dengue virus-bearing mosquito vectors can inflow to Jeju Island from endemic area such as Vietnam by increased international travel, and this mosquito vector's survival during colder winter months will likely occur due to the effects of climate change. In this section, we show the geographical distribution of medically important mosquito vectors such as Ae. albopictus, a vector of both dengue and chikungunya viruses; Culex pipiens, a vector of West Nile virus; and Anopheles sinensis, a vector of Plasmodium vivax, within Jeju Island, South Korea. We found a significant association between the mean temperature, amount of precipitation, and density of mosquitoes. The phylogenetic analyses show that an Ae. albopictus, collected in southern area of Jeju Island, was identical to specimens found in Ho Chi Minh, Vietnam, and not Nagasaki, Japan. Our results suggest that mosquito vectors or virus-bearing vectors can transmit from epidemic regions of Southeast Asia to Jeju Island and can survive during colder winter months. Therefore, Jeju Island is no longer safe from vector borne diseases (VBDs) due to the effects of globalization and climate change, and we should immediately monitor regional climate change to identify newly emerging VBDs.

Synergy between Repellents and Organophosphates on Bed Nets: Efficacy and Behavioural Response of Natural Free-Flying An. gambiae Mosquitoes

PubMed Central

Pennetier, Cédric; Costantini, Carlo; Corbel, Vincent; Licciardi, Séverine; Dabiré, Roch K.; Lapied, Bruno; Chandre, Fabrice; Hougard, Jean-Marc

2009-01-01

Background Chemicals are used on bed nets in order to prevent infected bites and to kill aggressive malaria vectors. Because pyrethroid resistance has become widespread in the main malaria vectors, research for alternative active ingredients becomes urgent. Mixing a repellent and a non-pyrethroid insecticide seemed to be a promising tool as mixtures in the laboratory showed the same features as pyrethroids. Methodology/Principal Findings We present here the results of two trials run against free-flying Anopheles gambiae populations comparing the effects of two insect repellents (either DEET or KBR 3023, also known as icaridin) and an organophosphate insecticide at low-doses (pirimiphos-methyl, PM) used alone and in combination on bed nets. We showed that mixtures of PM and the repellents induced higher exophily, blood feeding inhibition and mortality among wild susceptible and resistant malaria vectors than compounds used alone. Nevertheless the synergistic interactions are only involved in the high mortality induced by the two mixtures. Conclusion These field trials argue in favour of the strategy of mixing repellent and organophosphate on bed nets to better control resistant malaria vectors. PMID:19936249

Symmetry enhancement of extremal horizons in D  =  5 supergravity

NASA Astrophysics Data System (ADS)

Kayani, U.

2018-06-01

We consider the near-horizon geometry of supersymmetric extremal black holes in un-gauged and gauged 5-dimensional supergravity, coupled to abelian vector multiplets. By analyzing the global properties of the Killing spinors, we prove that the near-horizon geometries undergo a supersymmetry enhancement. This follows from a set of generalized Lichnerowicz-type theorems we establish, together with an index theory argument. As a consequence, these solutions always admit a symmetry group.

Asymptotically spacelike warped anti-de Sitter spacetimes in generalized minimal massive gravity

NASA Astrophysics Data System (ADS)

Setare, M. R.; Adami, H.

2017-06-01

In this paper we show that warped AdS3 black hole spacetime is a solution of the generalized minimal massive gravity (GMMG) and introduce suitable boundary conditions for asymptotically warped AdS3 spacetimes. Then we find the Killing vector fields such that transformations generated by them preserve the considered boundary conditions. We calculate the conserved charges which correspond to the obtained Killing vector fields and show that the algebra of the asymptotic conserved charges is given as the semi direct product of the Virasoro algebra with U(1) current algebra. We use a particular Sugawara construction to reconstruct the conformal algebra. Thus, we are allowed to use the Cardy formula to calculate the entropy of the warped black hole. We demonstrate that the gravitational entropy of the warped black hole exactly coincides with what we obtain via Cardy’s formula. As we expect, the warped Cardy formula also gives us exactly the same result as we obtain from the usual Cardy’s formula. We calculate mass and angular momentum of the warped black hole and then check that obtained mass, angular momentum and entropy to satisfy the first law of the black hole mechanics. According to the results of this paper we believe that the dual theory of the warped AdS3 black hole solution of GMMG is a warped CFT.

A Cysteine Protease Is Critical for Babesia spp. Transmission in Haemaphysalis Ticks

PubMed Central

Tsuji, Naotoshi; Miyoshi, Takeharu; Battsetseg, Badger; Matsuo, Tomohide; Xuan, Xuenan; Fujisaki, Kozo

2008-01-01

Vector ticks possess a unique system that enables them to digest large amounts of host blood and to transmit various animal and human pathogens, suggesting the existence of evolutionally acquired proteolytic mechanisms. We report here the molecular and reverse genetic characterization of a multifunctional cysteine protease, longipain, from the babesial parasite vector tick Haemaphysalis longicornis. Longipain shares structural similarity with papain-family cysteine proteases obtained from invertebrates and vertebrates. Endogenous longipain was mainly expressed in the midgut epithelium and was specifically localized at lysosomal vacuoles and possibly released into the lumen. Its expression was up-regulated by host blood feeding. Enzymatic functional assays using in vitro and in vivo substrates revealed that longipain hydrolysis occurs over a broad range of pH and temperature. Haemoparasiticidal assays showed that longipain dose-dependently killed tick-borne Babesia parasites, and its babesiacidal effect occurred via specific adherence to the parasite membranes. Disruption of endogenous longipain by RNA interference revealed that longipain is involved in the digestion of the host blood meal. In addition, the knockdown ticks contained an increased number of parasites, suggesting that longipain exerts a killing effect against the midgut-stage Babesia parasites in ticks. Our results suggest that longipain is essential for tick survival, and may have a role in controlling the transmission of tick-transmittable Babesia parasites. PMID:18483546

Development and evaluation of mosquito-electrocuting traps as alternatives to the human landing catch technique for sampling host-seeking malaria vectors.

PubMed

Maliti, Deodatus V; Govella, Nicodem J; Killeen, Gerry F; Mirzai, Nosrat; Johnson, Paul C D; Kreppel, Katharina; Ferguson, Heather M

2015-12-15

The human landing catch (HLC) is the gold standard method for sampling host-seeking malaria vectors. However, the HLC is ethically questionable because it requires exposure of humans to potentially infectious mosquito bites. Two exposure-free methods for sampling host-seeking mosquitoes were evaluated using electrocuting surfaces as potential replacements for HLC: (1) a previously evaluated, commercially available electrocuting grid (CA-EG) designed for killing flies, and (2) a custom-made mosquito electrocuting trap (MET) designed to kill African malaria vectors. The MET and the CA-EG were evaluated relative to the HLC in a Latin Square experiment conducted in the Kilombero Valley, Tanzania. The sampling consistency of the traps across the night and at varying mosquito densities was investigated. Estimates of the proportion of mosquitoes caught indoors (P(i)), proportion of human exposure occurring indoors (π(i)), and proportion of mosquitoes caught when most people are likely to be indoors (P(fl)) were compared for all traps. Whereas the CA-EG performed poorly (<10% of catch of HLC), sampling efficiency of the MET for sampling Anopheles funestus s.l. was indistinguishable from HLC indoors and outdoors. For Anopheles gambiae s.l., sampling sensitivity of MET was 20.9% (95% CI 10.3-42.2) indoors and 58.5% (95% CI 32.2-106.2) outdoors relative to HLC. There was no evidence of density-dependent sampling by the MET or CA-EG. Similar estimates of P(i) were obtained for An. gambiae s.l. and An. funestus s.l. from all trapping methods. The proportion of mosquitoes caught when people are usually indoors (P(fl)) was underestimated by the CA-EG and MET for An. gambiae s.l., but similar to the HLC for An. funestus. Estimates of the proportion of human exposure occurring indoors (π(i)) obtained from the CA-EG and MET were similar to the HLC for An. gambiae s.l., but overestimated for An. funestus. The MET showed promise as an outdoor sampling tool for malaria vectors where it achieved >50% sampling sensitivity relative to the HLC. The CA-EG had poor sampling sensitivity outdoors and inside. With further modification, the MET could provide an efficient and safer alternative to the HLC for the surveillance of mosquito vectors outdoors.

Parainfluenza Virus Infection Sensitizes Cancer Cells to DNA-Damaging Agents: Implications for Oncolytic Virus Therapy.

PubMed

Fox, Candace R; Parks, Griffith D

2018-04-01

A parainfluenza virus 5 (PIV5) with mutations in the P/V gene (P/V-CPI - ) is restricted for spread in normal cells but not in cancer cells in vitro and is effective at reducing tumor burdens in mouse model systems. Here we show that P/V-CPI - infection of HEp-2 human laryngeal cancer cells results in the majority of the cells dying, but unexpectedly, over time, there is an emergence of a population of cells that survive as P/V-CPI - persistently infected (PI) cells. P/V-CPI - PI cells had elevated levels of basal caspase activation, and viability was highly dependent on the activity of cellular inhibitor-of-apoptosis proteins (IAPs) such as Survivin and XIAP. In challenge experiments with external inducers of apoptosis, PI cells were more sensitive to cisplatin-induced DNA damage and cell death. This increased cisplatin sensitivity correlated with defects in DNA damage signaling pathways such as phosphorylation of Chk1 and translocation of damage-specific DNA binding protein 1 (DDB1) to the nucleus. Cisplatin-induced killing of PI cells was sensitive to the inhibition of wild-type (WT) p53-inducible protein 1 (WIP1), a phosphatase which acts to terminate DNA damage signaling pathways. A similar sensitivity to cisplatin was seen with cells during acute infection with P/V-CPI - as well as during acute infections with WT PIV5 and the related virus human parainfluenza virus type 2 (hPIV2). Our results have general implications for the design of safer paramyxovirus-based vectors that cannot establish PI as well as the potential for combining chemotherapy with oncolytic RNA virus vectors. IMPORTANCE There is intense interest in developing oncolytic viral vectors with increased potency against cancer cells, particularly those cancer cells that have gained resistance to chemotherapies. We have found that infection with cytoplasmically replicating parainfluenza virus can result in increases in the killing of cancer cells by agents that induce DNA damage, and this is linked to alterations to DNA damage signaling pathways that balance cell survival versus death. Our results have general implications for the design of safer paramyxovirus-based vectors that cannot establish persistent infection, the repurposing of drugs that target cellular IAPs as antivirals, and the combined use of DNA-damaging chemotherapy agents in conjunction with oncolytic RNA virus vectors. Copyright © 2018 American Society for Microbiology.

Pilot study on the combination of an organophosphate-based insecticide paint and pyrethroid-treated long lasting nets against pyrethroid resistant malaria vectors in Burkina Faso.

PubMed

Mosqueira, Beatriz; Soma, Dieudonné D; Namountougou, Moussa; Poda, Serge; Diabaté, Abdoulaye; Ali, Ouari; Fournet, Florence; Baldet, Thierry; Carnevale, Pierre; Dabiré, Roch K; Mas-Coma, Santiago

2015-08-01

A pilot study to test the efficacy of combining an organophosphate-based insecticide paint and pyrethroid-treated Long Lasting Insecticide Treated Nets (LLINs) against pyrethroid-resistant malaria vector mosquitoes was performed in a real village setting in Burkina Faso. Paint Inesfly 5A IGR™, comprised of two organophosphates (OPs) and an Insect Growth Regulator (IGR), was tested in combination with pyrethroid-treated LLINs. Efficacy was assessed in terms of mortality for 12 months using Early Morning Collections of malaria vectors and 30-minute WHO bioassays. Resistance to pyrethroids and OPs was assessed by detecting the frequency of L1014F and L1014S kdr mutations and Ace-1(R)G119S mutation, respectively. Blood meal origin was identified using a direct enzyme-linked immunosorbent assay (ELISA). The combination of Inesfly 5A IGR™ and LLINs was effective in killing 99.9-100% of malaria vector populations for 6 months regardless of the dose and volume treated. After 12 months, mortality rates decreased to 69.5-82.2%. The highest mortality rates observed in houses treated with 2 layers of insecticide paint and a larger volume. WHO bioassays supported these results: mortalities were 98.8-100% for 6 months and decreased after 12 months to 81.7-97.0%. Mortality rates in control houses with LLINs were low. Collected malaria vectors consisted exclusively of Anopheles coluzzii and were resistant to pyrethroids, with a L1014 kdr mutation frequency ranging from 60 to 98% through the study. About 58% of An. coluzzii collected inside houses had bloodfed on non-human animals. Combining Inesfly 5A IGR™ and LLINs yielded a one year killing efficacy against An. coluzzii highly resistant to pyrethroids but susceptible to OPs that exhibited an anthropo-zoophilic behaviour in the study area. The results obtained in a real setting supported previous work performed in experimental huts and underscore the need to study the impact that this novel strategy may have on clinical malaria and malaria exposure in children in a similar area of high pyrethroid resistance in South-Western Burkina Faso. Copyright © 2015 Elsevier B.V. All rights reserved.

Generalized wave operators, weighted Killing fields, and perturbations of higher dimensional spacetimes

NASA Astrophysics Data System (ADS)

Araneda, Bernardo

2018-04-01

We present weighted covariant derivatives and wave operators for perturbations of certain algebraically special Einstein spacetimes in arbitrary dimensions, under which the Teukolsky and related equations become weighted wave equations. We show that the higher dimensional generalization of the principal null directions are weighted conformal Killing vectors with respect to the modified covariant derivative. We also introduce a modified Laplace–de Rham-like operator acting on tensor-valued differential forms, and show that the wave-like equations are, at the linear level, appropriate projections off shell of this operator acting on the curvature tensor; the projection tensors being made out of weighted conformal Killing–Yano tensors. We give off shell operator identities that map the Einstein and Maxwell equations into weighted scalar equations, and using adjoint operators we construct solutions of the original field equations in a compact form from solutions of the wave-like equations. We study the extreme and zero boost weight cases; extreme boost corresponding to perturbations of Kundt spacetimes (which includes near horizon geometries of extreme black holes), and zero boost to static black holes in arbitrary dimensions. In 4D our results apply to Einstein spacetimes of Petrov type D and make use of weighted Killing spinors.

Development of recombinant adeno-associated virus vectors carrying small interfering RNA (shHec1)-mediated depletion of kinetochore Hec1 protein in tumor cells.

PubMed

Li, L; Yang, L; Scudiero, D A; Miller, S A; Yu, Z-X; Stukenberg, P T; Shoemaker, R H; Kotin, R M

2007-05-01

Transcript depletion using small interfering RNA (siRNA) technology represents a potentially valuable technique for the treatment of cancer. However, delivering therapeutic quantities of siRNA into solid tumors by chemical transfection is not feasible, whereas viral vectors efficiently transduce many human tumor cell lines. Yet producing sufficient quantities of viral vectors that elicit acute and selective cytotoxicity remains a major obstacle for preclinical and clinical trials. Using the invertebrate Spodoptera frugiperda (Sf9) cell line, we were able to produce high titer stocks of cytotoxic recombinant adeno-associated virus (rAAV) that express short hairpin RNA (shRNA) and that efficiently deplete Hec1 (highly expressed in cancer 1), or Kntc2 (kinetochore-associated protein 2), a kinetochore protein directly involved in kinetochore microtubule interactions, chromosome congression and spindle checkpoint signaling. Depletion of Hec1 protein results in persistent spindle checkpoint activation followed by cell death. Because Hec1 expression and activity are only present in mitotic cells, non-dividing cells were not affected by rAAV treatment. On the basis of the results of screening 56 human tumor cell lines with three different serotype vectors, we used a tumor xenograft model to test the effects in vivo. The effects of the shHec1 vector were evident in sectioned and stained tumors. The experiments with rAAV-shRNA vectors demonstrate the utility of producing vectors in invertebrate cells to obtain sufficient concentrations and quantities for solid tumor therapy. This addresses an important requirement for cancer gene therapy, to produce cytotoxic vectors in sufficient quantities and concentrations to enable quantitative transduction and selective killing of solid tumor cells.

Is a time symmetric interpretation of quantum theory possible without retrocausality?

PubMed Central

Pusey, Matthew F.

2017-01-01

Huw Price has proposed an argument that suggests a time symmetric ontology for quantum theory must necessarily be retrocausal, i.e. it must involve influences that travel backwards in time. One of Price's assumptions is that the quantum state is a state of reality. However, one of the reasons for exploring retrocausality is that it offers the potential for evading the consequences of no-go theorems, including recent proofs of the reality of the quantum state. Here, we show that this assumption can be replaced by a different assumption, called λ-mediation, that plausibly holds independently of the status of the quantum state. We also reformulate the other assumptions behind the argument to place them in a more general framework and pin down the notion of time symmetry involved more precisely. We show that our assumptions imply a timelike analogue of Bell's local causality criterion and, in doing so, give a new interpretation of timelike violations of Bell inequalities. Namely, they show the impossibility of a (non-retrocausal) time symmetric ontology. PMID:28690401

Fragmentation functions beyond fixed order accuracy

NASA Astrophysics Data System (ADS)

Anderle, Daniele P.; Kaufmann, Tom; Stratmann, Marco; Ringer, Felix

2017-03-01

We give a detailed account of the phenomenology of all-order resummations of logarithmically enhanced contributions at small momentum fraction of the observed hadron in semi-inclusive electron-positron annihilation and the timelike scale evolution of parton-to-hadron fragmentation functions. The formalism to perform resummations in Mellin moment space is briefly reviewed, and all relevant expressions up to next-to-next-to-leading logarithmic order are derived, including their explicit dependence on the factorization and renormalization scales. We discuss the details pertinent to a proper numerical implementation of the resummed results comprising an iterative solution to the timelike evolution equations, the matching to known fixed-order expressions, and the choice of the contour in the Mellin inverse transformation. First extractions of parton-to-pion fragmentation functions from semi-inclusive annihilation data are performed at different logarithmic orders of the resummations in order to estimate their phenomenological relevance. To this end, we compare our results to corresponding fits up to fixed, next-to-next-to-leading order accuracy and study the residual dependence on the factorization scale in each case.

Topologically nontrivial black holes in Lovelock-Born-Infeld gravity

NASA Astrophysics Data System (ADS)

Farhangkhah, N.

2018-04-01

We present the black hole solutions possessing horizon with nonconstant-curvature and additional scalar restrictions on the base manifold in Lovelock gravity coupled to Born-Infeld (BI) nonlinear electrodynamics. The asymptotic and near origin behavior of the metric is presented and we analyze different behaviors of the singularity. We find that, in contrast to the case of black hole solutions of BI-Lovelock gravity with constant curvature horizon and Maxwell-Lovelock gravity with non constant horizon which have only timelike singularities, spacelike, and timelike singularities may exist for BI-Lovelock black holes with nonconstant curvature horizon. By calculating the thermodynamic quantities, we study the effects of nonlinear electrodynamics via the Born-Infeld action. Stability analysis shows that black holes with positive sectional curvature, κ , possess an intermediate unstable phase and large and small black holes are stable. We see that while Ricci flat Lovelock-Born-Infeld black holes having exotic horizons are stable in the presence of Maxwell field or either Born Infeld field with large born Infeld parameter β , unstable phase appears for smaller values of β , and therefore nonlinearity brings in the instability.

Transverse Densities of Octet Baryons from Chiral Effective Field Theory

DOE PAGES

Alarcón, Jose Manuel; Hiller Blin, Astrid N.; Weiss, Christian

2017-03-24

Transverse densities describe the distribution of charge and current at fixed light-front time and provide a frame-independent spatial representation of hadrons as relativistic systems. In this paper, we calculate the transverse densities of the octet baryons at peripheral distances b=O(M π -1) in an approach that combines chiral effective field theory (χχEFT) and dispersion analysis. The densities are represented as dispersive integrals of the imaginary parts of the baryon electromagnetic form factors in the timelike region (spectral functions). The spectral functions on the two-pion cut at t>4Mmore » $$2\\atop{π}$$ are computed using relativistic χEFT with octet and decuplet baryons in the extended on-mass-shell renormalization scheme. The calculations are extended into the ρ-meson mass region using a dispersive method that incorporates the timelike pion form-factor data. The approach allows us to construct densities at distances b>1 fm with controlled uncertainties. Finally, our results provide insight into the peripheral structure of nucleons and hyperons and can be compared with empirical densities and lattice-QCD calculations.« less

Causal structures in Gauss-Bonnet gravity

NASA Astrophysics Data System (ADS)

Izumi, Keisuke

2014-08-01

We analyze causal structures in Gauss-Bonnet gravity. It is known that Gauss-Bonnet gravity potentially has superluminal propagation of gravitons due to its noncanonical kinetic terms. In a theory with superluminal modes, an analysis of causality based on null curves makes no sense, and thus, we need to analyze them in a different way. In this paper, using the method of the characteristics, we analyze the causal structure in Gauss-Bonnet gravity. We have the result that, on a Killing horizon, gravitons can propagate in the null direction tangent to the Killing horizon. Therefore, a Killing horizon can be a causal edge as in the case of general relativity; i.e. a Killing horizon is the "event horizon" in the sense of causality. We also analyze causal structures on nonstationary solutions with (D-2)-dimensional maximal symmetry, including spherically symmetric and flat spaces. If the geometrical null energy condition, RABNANB≥0 for any null vector NA, is satisfied, the radial velocity of gravitons must be less than or equal to that of light. However, if the geometrical null energy condition is violated, gravitons can propagate faster than light. Hence, on an evaporating black hole where the geometrical null energy condition is expected not to hold, classical gravitons can escape from the "black hole" defined with null curves. That is, the causal structures become nontrivial. It may be one of the possible solutions for the information loss paradox of evaporating black holes.

Trypanosoma cruzi: partial prevention of the natural infection of guinea pigs with a killed parasite vaccine.

PubMed

Basombrio, M A

1990-07-01

Guinea pigs are natural reservoirs of Chagas' disease. Domestic breeding and local trade of these animals are common practices among andean communities in South America. Infection by Trypanosoma cruzi occurs when the animals live in triatomine-infested houses or yards. The preventive effect of a vaccine consisting of cultured T. cruzi killed by freezing and thawing plus saponin was tested both in mice and in the guinea pig ecosystem. Resistance against T. cruzi challenge in mice was improved by increasing the trypomastigote/epimastigote ratio in live attenuated vaccines but not in killed parasite vaccines. Although the killing of attenuated parasites sharply reduced their immunogenicity for mice, a protective effect against natural T. cruzi infection was detected in guinea pigs. A total of 88 guinea pigs were vaccinated in four intradermal sites on three occasions. Eighty controls received similar inoculations of culture medium plus saponin. All animals were kept in a triatomine-infested yard. Parasitemia was studied with the capillary microhematocrit method. After an exposure time averaging 4 months, natural T. cruzi infection occurred in 55% (44/80) of the controls and in 33% (29/88) of the vaccinated group (P less than 0.01). The number of highly parasitemic guinea pigs was also significantly decreased (6/80 vs 0/88, P less than 0.01). Thus, immunizing protocols which are only partially protective against artificial callenge with T. cruzi may nevertheless constrain the exchange of parasites between natural hosts and vectors.

Determination of Airborne Concentrations of Dichlorvos Over a Range of Temperatures When Using Commercially Available Pesticide Strips In a Simulated Military Guard Post

DTIC Science & Technology

2013-03-22

insects, such as mosquitoes and sand flies. Currently, in the Afghanistan area of operations (AO), there is an intermediate to high risk for vector...Agency (EPA) to kill flies, mosquitoes , gnats, bedbugs, and other arthropod pests. Available in two sizes, the strips are hung in an enclosed room with...toluamide (DEET) to repel biting insects, further assists in protecting exposed personnel. Buildings and areas are also protected from insects by

Gyroscope precession along bound equatorial plane orbits around a Kerr black hole

NASA Astrophysics Data System (ADS)

Bini, Donato; Geralico, Andrea; Jantzen, Robert T.

2016-09-01

The precession of a test gyroscope along stable bound equatorial plane orbits around a Kerr black hole is analyzed, and the precession angular velocity of the gyro's parallel transported spin vector and the increment in the precession angle after one orbital period is evaluated. The parallel transported Marck frame which enters this discussion is shown to have an elegant geometrical explanation in terms of the electric and magnetic parts of the Killing-Yano 2-form and a Wigner rotation effect.

Hypoxia/hepatoma dual specific suicide gene expression plasmid delivery using bio-reducible polymer for hepatocellular carcinoma therapy.

PubMed

Kim, Hyun Ah; Nam, Kihoon; Lee, Minhyung; Kim, Sung Wan

2013-10-10

Gene therapy is suggested as a promising alternative strategy of hepatocellular carcinoma (HCC, also called hepatoma) therapy. To achieve a successful and safe gene therapy, tight regulation of gene expression is required to minimize side-effects in normal tissues. In this study, we developed a novel hypoxia and hepatoma dual specific gene expression vector. The constructed vectors were transfected into various cell lines using bio-reducible polymer, PAM-ABP. First, pAFPS-Luc or pAFPL-Luc vector was constructed with the alpha-fectoprotein (AFP) promoter and enhancer for hepatoma tissue specific gene expression. Then, pEpo-AFPL-Luc was constructed by insertion of the erythropoietin (Epo) enhancer for hypoxic cancer specific gene expression. In vitro transfection assay showed that pEpo-AFPL-Luc transfected hepatoma cell increased gene expression under hypoxic condition. To confirm the therapeutic effect of dual specific vector, herpes simplex virus thymidine kinase (HSV-TK) gene was introduced for cancer cell killing. The pEpo-AFPL-TK was transfected into hepatoma cell lines in the presence of ganciclovir (GCV) pro-drug. Caspase-3/7, MTT and TUNEL assays elucidated that pEpo-AFPL-TK transfected cells showed significant increasing of death rate in hypoxic hepatoma cells compared to controls. Therefore, the hypoxia/hepatoma dual specific gene expression vector with the Epo enhancer and AFP promoter may be useful for hepatoma specific gene therapy. © 2013.

Developing an expanded vector control toolbox for malaria elimination

PubMed Central

Tatarsky, Allison; Diabate, Abdoulaye; Chaccour, Carlos J; Marshall, John M; Okumu, Fredros O; Brunner, Shannon; Newby, Gretchen; Williams, Yasmin A; Malone, David; Tusting, Lucy S; Gosling, Roland D

2017-01-01

Vector control using long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) accounts for most of the malaria burden reductions achieved recently in low and middle-income countries (LMICs). LLINs and IRS are highly effective, but are insufficient to eliminate malaria transmission in many settings because of operational constraints, growing resistance to available insecticides and mosquitoes that behaviourally avoid contact with these interventions. However, a number of substantive opportunities now exist for rapidly developing and implementing more diverse, effective and sustainable malaria vector control strategies for LMICs. For example, mosquito control in high-income countries is predominantly achieved with a combination of mosquito-proofed housing and environmental management, supplemented with large-scale insecticide applications to larval habitats and outdoor spaces that kill off vector populations en masse, but all these interventions remain underused in LMICs. Programmatic development and evaluation of decentralised, locally managed systems for delivering these proactive mosquito population abatement practices in LMICs could therefore enable broader scale-up. Furthermore, a diverse range of emerging or repurposed technologies are becoming available for targeting mosquitoes when they enter houses, feed outdoors, attack livestock, feed on sugar or aggregate into mating swarms. Global policy must now be realigned to mobilise the political and financial support necessary to exploit these opportunities over the decade ahead, so that national malaria control and elimination programmes can access a much broader, more effective set of vector control interventions. PMID:28589022

Future Perspectives on Baryon Form Factor Measurements with BES III

NASA Astrophysics Data System (ADS)

Schönning, Karin; Li, Cui

2017-03-01

The electromagnetic structure of hadrons, parameterised in terms of electromagnetic form factors, EMFF's, provide a key to the strong interaction. Nucleon EMFF's have been studied rigorously for more than 60 years but the new techniques and larger data samples available at modern facilities have given rise to a renewed interest for the field. Recently, the access to hyperon structure by hyperon time-like EMFF provides an additional dimension. The BEijing Spectrometer (BES III) at the Beijing Electron Positron Collider (BEPC-II) in China is the only running experiment where time-like baryon EMFF's can be studied in the e+e- → BB̅ reaction. The BES III detector is an excellent tool for baryon form factor measurements thanks to its near 4π coverage, precise tracking, PID and calorimetry. All hyperons in the SU(3) spin 1/2 octet and spin 3/2 decuplet are energetically accessible within the BEPC-II energy range. Recent data on proton and Λ hyperon form factors will be presented. Furthermore, a world-leading data sample was collected in 2014-2015 for precision measurements of baryon form factors. In particular, the data will enable a measurement of the relative phase between the electric and the magnetic form factors for Λ and Λc+ and hyperons. The modulus of the phase can be extracted from the hyperon polarisation, which in turn is experimentally accessible via the weak, parity violating decay. Furthermore, from the spin correlation between the outgoing hyperon and antihyperon, the sign of the phase can be extracted. This means that the time-like form factors can be completely determined for the first time. The methods will be outlined and the prospects of the BES III form factor measurements will be given. We will also present a planned upgrade of the BES III detector which is expected to improve future form factor measurements.

Embedding of the brane into six dimensions

NASA Astrophysics Data System (ADS)

Gogberashvili, Merab

2002-10-01

Embedding of the brane metric into Euclidean (2+4)-space is found. Brane geometry can be visualized as the surface of the hypersphere in six dimensions which ``radius'' is governed by the cosmological constant. Minkowski space in this picture is placed on the intersection of this surface with the plane formed by the extra space-like and time-like coordinates.

Tissue-Specific Expression of Herpes Simplex Virus Thymidine Kinase Gene Delivered by Adeno-Associated Virus Inhibits the Growth of Human Hepatocellular Carcinoma in Athymic Mice

NASA Astrophysics Data System (ADS)

Su, Hua; Lu, Ronghua; Chang, Judy C.; Kan, Yuet Wai

1997-12-01

About 70% of hepatocellular carcinomas are known to express α -fetoprotein, which is normally expressed in fetal but not in adult livers. To induce herpes simplex virus-thymidine kinase expression in these cancer cells, we constructed an adeno-associated viral vector containing the HSV-TK gene under the control of the α -fetoprotein enhancer and albumin promoter. We previously demonstrated in vitro that although this vector can transduce a variety of human cells, only transduced AFP and albumin-expressing hepatocellular carcinoma cell lines were sensitive to killing by ganciclovir (GCV). In the present study, we explored the effect of this vector on hepatocellular carcinoma cells in vivo. Subcutaneous tumors generated in nude mice by implanting hepatocellular carcinoma cells previously transduced with this vector shrank dramatically after treatment with GCV. Bystander effect was also observed on the tumors generated by mixing transduced and untransduced cells. To test whether the tumor cells can be transduced by the virus in vivo, we injected the recombinant adeno-associated virus into tumors generated by untransduced hepatocarcinoma cell line. Tumor growth were retarded after treatment with GCV. These experiments demonstrate the feasibility of in vivo transduction of tumor cell with rAAV.

Progress in directed energy control of vectors for microbes and other cells

NASA Astrophysics Data System (ADS)

Kiel, Johnathan L.; Parker, Jill E.; Holwitt, Eric A.; Vivekananda, Jeeva; Sloan, Mark A.; Stribling, Lucille J. V.

2004-07-01

Biosynthetic semiconductor, diazoluminomelanin (DALM), is a polymer of tyrosine, luminol, and nitrite. DALM has a very large cross section of absorption for light from ultraviolet to radio frequencies. This polymer can be made efficiently in a genetically engineered E.coli, JM109/pIC2ORNR1.1 (ATCC# 69905). We have been pursuing ways to couple electromagnetic radiation to vectors using this polymer. DNA capture elements (DCEs; formerly aptamers) have made this possible. We incorporated DCEs into the plasmid of this E. coli to direct binding to whatever microbe or cell desired and to produce DALM attached to the plasmid DNA. Using two other vectors pSV2neoNR101 or pSV2neoNR8005 (ATCC # 69617 and 69618, respectively), both propagated in the E. coli host HB101, we have also inserted genes necessary for DALM production into animal and human cell lines (mouse monocytic leukemia: ATCC # CRL- 11771, -11772, -1173, mouse mammary adenocarcinoma: ATCC# CRL-12184, -12185; and human carcinoma of the cervix: ATCC # CRL-12510). The DCE/DALM vectors can be used to tag target cells, detectable by broad-spectrum light absorbance, luminescence, or fluorescence. DCE/DALM can further be activated with light, microwave energy, or by oxidative chemistry to kill the targeted microbes or other cells.

Approaches to utilize mesenchymal progenitor cells as cellular vehicles.

PubMed

Pereboeva, L; Komarova, S; Mikheeva, G; Krasnykh, V; Curiel, D T

2003-01-01

Mammalian cells represent a novel vector approach for gene delivery that overcomes major drawbacks of viral and nonviral vectors and couples cell therapy with gene delivery. A variety of cell types have been tested in this regard, confirming that the ideal cellular vector system for ex vivo gene therapy has to comply with stringent criteria and is yet to be found. Several properties of mesenchymal progenitor cells (MPCs), such as easy access and simple isolation and propagation procedures, make these cells attractive candidates as cellular vehicles. In the current work, we evaluated the potential utility of MPCs as cellular vectors with the intent to use them in the cancer therapy context. When conventional adenoviral (Ad) vectors were used for MPC transduction, the highest transduction efficiency of MPCs was 40%. We demonstrated that Ad primary-binding receptors were poorly expressed on MPCs, while the secondary Ad receptors and integrins presented in sufficient amounts. By employing Ad vectors with incorporated integrin-binding motifs (Ad5lucRGD), MPC transduction was augmented tenfold, achieving efficient genetic loading of MPCs with reporter and anticancer genes. MPCs expressing thymidine kinase were able to exert a bystander killing effect on the cancer cell line SKOV3ip1 in vitro. In addition, we found that MPCs were able to support Ad replication, and thus can be used as cell vectors to deliver oncolytic viruses. Our results show that MPCs can foster expression of suicide genes or support replication of adenoviruses as potential anticancer therapeutic payloads. These findings are consistent with the concept that MPCs possess key properties that ensure their employment as cellular vehicles and can be used to deliver either therapeutic genes or viruses to tumor sites.

Synchronization of relativistic particles in the hyperbolic Kuramoto model

NASA Astrophysics Data System (ADS)

Ritchie, Louis M.; Lohe, M. A.; Williams, Anthony G.

2018-05-01

We formulate a noncompact version of the Kuramoto model by replacing the invariance group SO(2) of the plane rotations by the noncompact group SO(1, 1). The N equations of the system are expressed in terms of hyperbolic angles αi and are similar to those of the Kuramoto model, except that the trigonometric functions are replaced by hyperbolic functions. Trajectories are generally unbounded, nevertheless synchronization occurs for any positive couplings κi, arbitrary positive multiplicative parameters λi and arbitrary exponents ωi. There are no critical values for the coupling constants. We measure the onset of synchronization by means of several order and disorder parameters. We show numerically and by means of exact solutions for N = 2 that solutions can develop singularities if the coupling constants are negative, or if the initial values are not suitably restricted. We describe a physical interpretation of the system as a cluster of interacting relativistic particles in 1 + 1 dimensions, subject to linear repulsive forces with space-time trajectories parametrized by the rapidity αi. The trajectories synchronize provided that the particle separations remain predominantly time-like, and the synchronized cluster can be viewed as a bound state of N relativistic particle constituents. We extend the defining equations of the system to higher dimensions by means of vector equations which are covariant with respect to SO(p, q).

Extracting black-hole rotational energy: The generalized Penrose process

NASA Astrophysics Data System (ADS)

Lasota, J.-P.; Gourgoulhon, E.; Abramowicz, M.; Tchekhovskoy, A.; Narayan, R.

2014-01-01

In the case involving particles, the necessary and sufficient condition for the Penrose process to extract energy from a rotating black hole is absorption of particles with negative energies and angular momenta. No torque at the black-hole horizon occurs. In this article we consider the case of arbitrary fields or matter described by an unspecified, general energy-momentum tensor Tμν and show that the necessary and sufficient condition for extraction of a black hole's rotational energy is analogous to that in the mechanical Penrose process: absorption of negative energy and negative angular momentum. We also show that a necessary condition for the Penrose process to occur is for the Noether current (the conserved energy-momentum density vector) to be spacelike or past directed (timelike or null) on some part of the horizon. In the particle case, our general criterion for the occurrence of a Penrose process reproduces the standard result. In the case of relativistic jet-producing "magnetically arrested disks," we show that the negative energy and angular-momentum absorption condition is obeyed when the Blandford-Znajek mechanism is at work, and hence the high energy extraction efficiency up to ˜300% found in recent numerical simulations of such accretion flows results from tapping the black hole's rotational energy through the Penrose process. We show how black-hole rotational energy extraction works in this case by describing the Penrose process in terms of the Noether current.

Hidden symmetries of Eisenhart-Duval lift metrics and the Dirac equation with flux

NASA Astrophysics Data System (ADS)

Cariglia, Marco

2012-10-01

The Eisenhart-Duval lift allows embedding nonrelativistic theories into a Lorentzian geometrical setting. In this paper we study the lift from the point of view of the Dirac equation and its hidden symmetries. We show that dimensional reduction of the Dirac equation for the Eisenhart-Duval metric in general gives rise to the nonrelativistic Lévy-Leblond equation in lower dimension. We study in detail in which specific cases the lower dimensional limit is given by the Dirac equation, with scalar and vector flux, and the relation between lift, reduction, and the hidden symmetries of the Dirac equation. While there is a precise correspondence in the case of the lower dimensional massive Dirac equation with no flux, we find that for generic fluxes it is not possible to lift or reduce all solutions and hidden symmetries. As a by-product of this analysis, we construct new Lorentzian metrics with special tensors by lifting Killing-Yano and closed conformal Killing-Yano tensors and describe the general conformal Killing-Yano tensor of the Eisenhart-Duval lift metrics in terms of lower dimensional forms. Last, we show how, by dimensionally reducing the higher dimensional operators of the massless Dirac equation that are associated with shared hidden symmetries, it is possible to recover hidden symmetry operators for the Dirac equation with flux.

A New Clade of African Body and Head Lice Infected by Bartonella quintana and Yersinia pestis-Democratic Republic of the Congo.

PubMed

Drali, Rezak; Shako, Jean-Christophe; Davoust, Bernard; Diatta, Georges; Raoult, Didier

2015-11-01

The human body louse is known as a vector for the transmission of three serious diseases-specifically, epidemic typhus, trench fever, and relapsing fever caused by Rickettsia prowazekii, Bartonella quintana, and Borrelia recurrentis, respectively-that have killed millions of people. It is also suspected in the transmission of a fourth pathogen, Yersinia pestis, which is the etiologic agent of plague. To date, human lice belonging to the genus Pediculus have been classified into three mitochondrial clades: A, B, and C. Here, we describe a fourth mitochondrial clade, Clade D, comprising head and body lice. Clade D may be a vector of B. quintana and Y. pestis, which is prevalent in a highly plague-endemic area near the Rethy Health District, Orientale Province, Democratic Republic of the Congo. © The American Society of Tropical Medicine and Hygiene.

Existence and stability of circular orbits in general static and spherically symmetric spacetimes

NASA Astrophysics Data System (ADS)

Jia, Junji; Liu, Jiawei; Liu, Xionghui; Mo, Zhongyou; Pang, Xiankai; Wang, Yaoguang; Yang, Nan

2018-02-01

The existence and stability of circular orbits (CO) in static and spherically symmetric (SSS) spacetime are important because of their practical and potential usefulness. In this paper, using the fixed point method, we first prove a necessary and sufficient condition on the metric function for the existence of timelike COs in SSS spacetimes. After analyzing the asymptotic behavior of the metric, we then show that asymptotic flat SSS spacetime that corresponds to a negative Newtonian potential at large r will always allow the existence of CO. The stability of the CO in a general SSS spacetime is then studied using the Lyapunov exponent method. Two sufficient conditions on the (in)stability of the COs are obtained. For null geodesics, a sufficient condition on the metric function for the (in)stability of null CO is also obtained. We then illustrate one powerful application of these results by showing that three SSS spacetimes whose metric function is not completely known will allow the existence of timelike and/or null COs. We also used our results to assert the existence and (in)stabilities of a number of known SSS metrics.

A new approach to spherically symmetric junction surfaces and the matching of FLRW regions

NASA Astrophysics Data System (ADS)

Kirchner, U.

2004-08-01

We investigate timelike junctions (with surface layer) between spherically symmetric solutions of the Einstein-field equation. In contrast to previous investigations, this is done in a coordinate system in which the junction surface motion is absorbed in the metric, while all coordinates are continuous at the junction surface. The evolution equations for all relevant quantities are derived. We discuss the no-surface layer case (boundary surface) and study the behaviour for small surface energies. It is shown that one should expect cases in which the speed of light is reached within a finite proper time. We carefully discuss necessary and sufficient conditions for a possible matching of spherically symmetric sections. For timelike junctions between spherically symmetric spacetime sections we show explicitly that the time component of the Lanczos equation always reduces to an identity (independent of the surface equation of state). The results are applied to the matching of Friedmann Lemaître Robertson Walker (FLRW) models. We discuss 'vacuum bubbles' and closed open junctions in detail. As illustrations several numerical integration results are presented, some of them indicate that (observers comoving with) the junction surface can reach the speed of light within a finite time.

Cosmological singularities in Bakry-Émery spacetimes

NASA Astrophysics Data System (ADS)

Galloway, Gregory J.; Woolgar, Eric

2014-12-01

We consider spacetimes consisting of a manifold with Lorentzian metric and a weight function or scalar field. These spacetimes admit a Bakry-Émery-Ricci tensor which is a natural generalization of the Ricci tensor. We impose an energy condition on the Bakry-Émery-Ricci tensor and obtain singularity theorems of a cosmological type, both for zero and for positive cosmological constant. That is, we find conditions under which every timelike geodesic is incomplete. These conditions are given by 'open' inequalities, so we examine the borderline (equality) cases and show that certain singularities are avoided in these cases only if the geometry is rigid; i.e., if it splits as a Lorentzian product or, for a positive cosmological constant, a warped product, and the weight function is constant along the time direction. Then the product case is future timelike geodesically complete while, in the warped product case, worldlines of certain conformally static observers are complete. Our results answer a question posed by J Case. We then apply our results to the cosmology of scalar-tensor gravitation theories. We focus on the Brans-Dicke family of theories in 4 spacetime dimensions, where we obtain 'Jordan frame' singularity theorems for big bang singularities.

Superconducting cosmic string: Equation of state for spacelike and timelike current in the neutral limit

NASA Astrophysics Data System (ADS)

Peter, Patrick

1992-02-01

The equation of state relating the tension T and the energy per unit length U of a cosmic string is investigated in the simplest nontrivial case, namely, that of a field theory with U(1)local×U(1)global invariance, in four dimensions, which is interpretable as the zero-charge-coupling-constant limit of the more general superconducting string models that have been previously investigated. This limit has the advantage of giving vacuum vortex defects that are strictly local so that the quantities such as U and T that are relevant for the macroscopic description can be computed without ambiguity. In the case of ``electric'' states (with timelike current) for which no comparable previous calculations exist, it is shown there is a critical frequency wc beyond which the vortex becomes unstable due to ``charge'' carrier emission. In the case of ``magnetic'' states (with spacelike current), the present analysis provides more precise results than those of previous investigations, whose predictions are broadly confirmed for typical moderate models in which the tension T remains comparable to the energy density U though not for extreme models, in which serious discrepancies are revealed.

Stability of marginally outer trapped surfaces and symmetries

NASA Astrophysics Data System (ADS)

Carrasco, Alberto; Mars, Marc

2009-09-01

We study the properties of stable, strictly stable and locally outermost marginally outer trapped surfaces in spacelike hypersurfaces of spacetimes possessing certain symmetries such as isometries, homotheties and conformal Killings. We first obtain results for general diffeomorphisms in terms of the so-called metric deformation tensor and then particularize to different types of symmetries. In particular, we find restrictions at the surfaces on the vector field generating the symmetry. Some consequences are discussed. As an application, we present a result on non-existence of stable marginally outer trapped surfaces in slices of FLRW.

Lift of noninvariant solutions of heavenly equations from three to four dimensions and new ultra-hyperbolic metrics

NASA Astrophysics Data System (ADS)

Malykh, A. A.; Nutku, Y.; Sheftel, M. B.

2007-08-01

We demonstrate that partner symmetries provide a lift of noninvariant solutions of the three-dimensional Boyer-Finley equation to noninvariant solutions of the four-dimensional hyperbolic complex Monge-Ampère equation. The lift is applied to noninvariant solutions of the Boyer-Finley equation, obtained earlier by the method of group foliation, to yield noninvariant solutions of the hyperbolic complex Monge-Ampère equation. Using these solutions we construct new Ricci-flat ultra-hyperbolic metrics with non-zero curvature tensor that have no Killing vectors.

Partner symmetries and non-invariant solutions of four-dimensional heavenly equations

NASA Astrophysics Data System (ADS)

Malykh, A. A.; Nutku, Y.; Sheftel, M. B.

2004-07-01

We extend our method of partner symmetries to the hyperbolic complex Monge-Ampère equation and the second heavenly equation of Plebañski. We show the existence of partner symmetries and derive the relations between them. For certain simple choices of partner symmetries the resulting differential constraints together with the original heavenly equations are transformed to systems of linear equations by an appropriate Legendre transformation. The solutions of these linear equations are generically non-invariant. As a consequence we obtain explicitly new classes of heavenly metrics without Killing vectors.

Singularities and the geometry of spacetime

NASA Astrophysics Data System (ADS)

Hawking, Stephen

2014-11-01

The aim of this essay is to investigate certain aspects of the geometry of the spacetime manifold in the General Theory of Relativity with particular reference to the occurrence of singularities in cosmological solutions and their relation with other global properties. Section 2 gives a brief outline of Riemannian geometry. In Section 3, the General Theory of Relativity is presented in the form of two postulates and two requirements which are common to it and to the Special Theory of Relativity, and a third requirement, the Einstein field equations, which distinguish it from the Special Theory. There does not seem to be any alternative set of field equations which would not have some undeseriable features. Some exact solutions are described. In Section 4, the physical significance of curvature is investigated using the deviation equation for timelike and null curves. The Riemann tensor is decomposed into the Ricci tensor which represents the gravitational effect at a point of matter at that point and the Welyl tensor which represents the effect at a point of gravitational radiation and matter at other points. The two tensors are related by the Bianchi identities which are presented in a form analogous to the Maxwell equations. Some lemmas are given for the occurrence of conjugate points on timelike and null geodesics and their relation with the variation of timelike and null curves is established. Section 5 is concerned with properties of causal relations between points of spacetime. It is shown that these could be used to determine physically the manifold structure of spacetime if the strong causality assumption held. The concepts of a null horizon and a partial Cauchy surface are introduced and are used to prove a number of lemmas relating to the existence of a timelike curve of maximum length between two sets. In Section 6, the definition of a singularity of spacetime is given in terms of geodesic incompleteness. The various energy assumptions needed to prove the occurrence of singularities are discussed and then a number of theorems are presented which prove the occurrence of singularities in most cosmological solutions. A procedure is given which could be used to describe and classify the singularites and their expected nature is discussed. Sections 2 and 3 are reviews of standard work. In Section 4, the deviation equation is standard but the matrix method used to analyse it is the author's own as is the decomposition given of the Bianchi identities (this was also obtained independently by Trümper). Variation of curves and conjugate points are standard in a positive-definite metric but this seems to be the first full account for timelike and null curves in a Lorentz metric. Except where otherwise indicated in the text, Sections 5 and 6 are the work of the author who, however, apologises if through ignorance or inadvertance he has failed to make acknowledgements where due. Some of this work has been described in [Hawking S.W. 1965b. Occurrence of singularities in open universes. Phys. Rev. Lett. 15: 689-690; Hawking S.W. and G.F.R. Ellis. 1965c. Singularities in homogeneous world models. Phys. Rev. Lett. 17: 246-247; Hawking S.W. 1966a. Singularities in the universe. Phys. Rev. Lett. 17: 444-445; Hawking S.W. 1966c. The occurrence of singularities in cosmology. Proc. Roy. Soc. Lond. A 294: 511-521]. Undoubtedly, the most important results are the theorems in Section 6 on the occurrence of singularities. These seem to imply either that the General Theory of Relativity breaks down or that there could be particles whose histories did not exist before (or after) a certain time. The author's own opinion is that the theory probably does break down, but only when quantum gravitational effects become important. This would not be expected to happen until the radius of curvature of spacetime became about 10-14 cm.

Temporal frequency of knockdown resistance mutations, F1534C and V1016G, in Aedes aegypti in Chiang Mai city, Thailand and the impact of the mutations on the efficiency of thermal fogging spray with pyrethroids.

PubMed

Plernsub, Suriya; Saingamsook, Jassada; Yanola, Jintana; Lumjuan, Nongkran; Tippawangkosol, Pongsri; Walton, Catherine; Somboon, Pradya

2016-10-01

In Thailand, control of dengue outbreaks is currently attained by the use of space sprays, particularly thermal fogging using pyrethroids, with the aim of killing infected Aedes mosquito vectors in epidemic areas. However, the principal dengue vector, Aedes aegypti, is resistant to pyrethroids conferred mainly by mutations in the voltage-gated sodium channel gene, F1534C and V1016G, termed knockdown resistance (kdr). The objectives of this study were to determine the temporal frequencies of F1534C and V1016G in Ae. aegypti populations in relation to pyrethroid resistance in Chiang Mai city, and to evaluate the impact of the mutations on the efficacy of thermal fogging with the pyrethroid deltamethrin. Larvae and pupae were collected from several areas around Chiang Mai city during 2011-2015 and reared to adulthood for bioassays for deltamethrin susceptibility. These revealed no trend of increasing deltamethrin resistance during the study period (mortality 58.0-69.5%, average 62.8%). This corresponded to no overall change in the frequencies of the C1534 allele (0.55-0.66, average 0.62) and G1016 allele (0.34-0.45, average 0.38), determined using allele specific amplification. Only three genotypes of kdr mutations were detected: C1534 homozygous (VV/CC); G1016/C1534 double heterozygous (VG/FC); and G1016 homozygous (GG/FF) indicating that the F1534C and V1016G mutations occurred on separate haplotypic backgrounds and a lack of recombination between them to date. The F1 progeny females were used to evaluate the efficacy of thermal fogging spray with Damthrin-SP(®) (deltamethrin+S-bioallethrin+piperonyl butoxide) using a caged mosquito bioassay. The thermal fogging spray killed 100% and 61.3% of caged mosquito bioassay placed indoors and outdoors, respectively. The outdoor spray had greater killing effect on C1534 homozygous and had partially effect on double heterozygous mosquitoes, but did not kill any G1016 homozygous mutants living outdoors. As this selection pressure would be expected to have led to an increase in frequency of the G1016 allele, it is likely that the relatively stable kdr mutation allele frequencies observed here result from balancing selection, in the form of overdominance for VG/FC genotypes and/or the effects of fluctuating environments that vary in insecticide exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

Biological Control of the Chagas Disease Vector Triatoma infestans with the Entomopathogenic Fungus Beauveria bassiana Combined with an Aggregation Cue: Field, Laboratory and Mathematical Modeling Assessment

PubMed Central

Forlani, Lucas; Pedrini, Nicolás; Girotti, Juan R.; Mijailovsky, Sergio J.; Cardozo, Rubén M.; Gentile, Alberto G.; Hernández-Suárez, Carlos M.; Rabinovich, Jorge E.; Juárez, M. Patricia

2015-01-01

Background Current Chagas disease vector control strategies, based on chemical insecticide spraying, are growingly threatened by the emergence of pyrethroid-resistant Triatoma infestans populations in the Gran Chaco region of South America. Methodology and findings We have already shown that the entomopathogenic fungus Beauveria bassiana has the ability to breach the insect cuticle and is effective both against pyrethroid-susceptible and pyrethroid-resistant T. infestans, in laboratory as well as field assays. It is also known that T. infestans cuticle lipids play a major role as contact aggregation pheromones. We estimated the effectiveness of pheromone-based infection boxes containing B. bassiana spores to kill indoor bugs, and its effect on the vector population dynamics. Laboratory assays were performed to estimate the effect of fungal infection on female reproductive parameters. The effect of insect exuviae as an aggregation signal in the performance of the infection boxes was estimated both in the laboratory and in the field. We developed a stage-specific matrix model of T. infestans to describe the fungal infection effects on insect population dynamics, and to analyze the performance of the biopesticide device in vector biological control. Conclusions The pheromone-containing infective box is a promising new tool against indoor populations of this Chagas disease vector, with the number of boxes per house being the main driver of the reduction of the total domestic bug population. This ecologically safe approach is the first proven alternative to chemical insecticides in the control of T. infestans. The advantageous reduction in vector population by delayed-action fungal biopesticides in a contained environment is here shown supported by mathematical modeling. PMID:25969989

Initial boundary-value problem for the spherically symmetric Einstein equations with fluids with tangential pressure.

PubMed

Brito, Irene; Mena, Filipe C

2017-08-01

We prove that, for a given spherically symmetric fluid distribution with tangential pressure on an initial space-like hypersurface with a time-like boundary, there exists a unique, local in time solution to the Einstein equations in a neighbourhood of the boundary. As an application, we consider a particular elastic fluid interior matched to a vacuum exterior.

MEASUREMENTS OF σ(e+e-→ μ±μ∓) IN THE ENERGY RANGE 1.2-3.0 GeV

NASA Astrophysics Data System (ADS)

Alles-Borelli, V.; Bernardini, M.; Bollini, D.; Giusti, P.; Massam, T.; Monari, L.; Palmonari, F.; Valenti, G.; Zichichi, A.

The analysis of 1466 events of the type e+e-→ μ±μ∓ in the time-like range from 1.44 to 9.00 GeV2, shows that the absolute value of the cross-section and its energy dependence follow QED expectations within (± 3.2%) and (± 1.2%), respectively.

Smoothness of the future and past trapped sets in Kerr–Newman–Taub-NUT spacetimes

NASA Astrophysics Data System (ADS)

Paganini, Claudio F.; Oancea, Marius A.

2018-03-01

We consider the sets of future/past trapped null geodesics in the exterior region of a sub-extremal Kerr–Newman–Taub-NUT spacetime. We show that from the point of view of any timelike observer outside of such a black hole, trapping can be understood as two smooth sets of spacelike directions on the celestial sphere of the observer.

Amelioration of murine beta-thalassemia through drug selection of hematopoietic stem cells transduced with a lentiviral vector encoding both gamma-globin and the MGMT drug-resistance gene.

PubMed

Zhao, Huifen; Pestina, Tamara I; Nasimuzzaman, Md; Mehta, Perdeep; Hargrove, Phillip W; Persons, Derek A

2009-06-04

Correction of murine models of beta-thalassemia has been achieved through high-level globin lentiviral vector gene transfer into mouse hematopoietic stem cells (HSCs). However, transduction of human HSCs is less robust and may be inadequate to achieve therapeutic levels of genetically modified erythroid cells. We therefore developed a double gene lentiviral vector encoding both human gamma-globin under the transcriptional control of erythroid regulatory elements and methylguanine methyltransferase (MGMT), driven by a constitutive cellular promoter. MGMT expression provides cellular resistance to alkylator drugs, which can be administered to kill residual untransduced, diseased HSCs, whereas transduced cells are protected. Mice transplanted with beta-thalassemic HSCs transduced with a gamma-globin/MGMT vector initially had subtherapeutic levels of red cells expressing gamma-globin. To enrich gamma-globin-expressing cells, transplanted mice were treated with the alkylator agent 1,3-bis-chloroethyl-1-nitrosourea. This resulted in significant increases in the number of gamma-globin-expressing red cells and the amount of fetal hemoglobin, leading to resolution of anemia. Selection of transduced HSCs was also obtained when cells were drug-treated before transplantation. Mice that received these cells demonstrated reconstitution with therapeutic levels of gamma-globin-expressing cells. These data suggest that MGMT-based drug selection holds promise as a modality to improve gene therapy for beta-thalassemia.

A heterotypic bystander effect for tumor cell killing after adeno-associated virus/phage-mediated, vascular-targeted suicide gene transfer.

PubMed

Trepel, Martin; Stoneham, Charlotte A; Eleftherohorinou, Hariklia; Mazarakis, Nicholas D; Pasqualini, Renata; Arap, Wadih; Hajitou, Amin

2009-08-01

Suicide gene transfer is the most commonly used cytotoxic approach in cancer gene therapy; however, a successful suicide gene therapy depends on the generation of efficient targeted systemic gene delivery vectors. We recently reported that selective systemic delivery of suicide genes such as herpes simplex virus thymidine kinase (HSVtk) to tumor endothelial cells through a novel targeted adeno-associated virus/phage vector leads to suppression of tumor growth. This marked effect has been postulated to result primarily from the death of cancer cells by hypoxia following the targeted disruption of tumor blood vessels. Here, we investigated whether an additional mechanism of action is involved. We show that there is a heterotypic "bystander" effect between endothelial cells expressing the HSVtk suicide gene and tumor cells. Treatment of cocultures of HSVtk-transduced endothelial cells and non-HSVtk-transduced tumor cells with ganciclovir results in the death of both endothelial and tumor cells. Blocking of this effect by 18alpha-glycyrrhetinic acid indicates that gap junctions between endothelial and tumor cells are largely responsible for this phenomenon. Moreover, the observed bystander killing is mediated by connexins 43 and 26, which are expressed in endothelial and tumor cell types. Finally, this heterotypic bystander effect is accompanied by a suppression of tumor growth in vivo that is independent of primary gene transfer into host-derived tumor vascular endothelium. These findings add an alternative nonmutually exclusive and potentially synergistic cytotoxic mechanism to cancer gene therapy based on targeted adeno-associated virus/phage and further support the promising role of nonmalignant tumor stromal cells as therapeutic targets.

Engineered T cells for pancreatic cancer treatment

PubMed Central

Katari, Usha L; Keirnan, Jacqueline M; Worth, Anna C; Hodges, Sally E; Leen, Ann M; Fisher, William E; Vera, Juan F

2011-01-01

Objective Conventional chemotherapy and radiotherapy produce marginal survival benefits in pancreatic cancer, underscoring the need for novel therapies. The aim of this study is to develop an adoptive T cell transfer approach to target tumours expressing prostate stem cell antigen (PSCA), a tumour-associated antigen that is frequently expressed by pancreatic cancer cells. Methods Expression of PSCA on cell lines and primary tumour samples was confirmed by immunohistochemistry. Healthy donor- and patient-derived T cells were isolated, activated in vitro using CD3/CD28, and transduced with a retroviral vector encoding a chimeric antigen receptor (CAR) targeting PSCA. The ability of these cells to kill tumour cells was analysed by chromium-51 (Cr51) release. Results Prostate stem cell antigen was expressed on >70% of the primary tumour samples screened. Activated, CAR-modified T cells could be readily generated in clinically relevant numbers and were specifically able to kill PSCA-expressing pancreatic cancer cell lines with no non-specific killing of PSCA-negative target cells, thus indicating the potential efficacy and safety of this approach. Conclusions Prostate stem cell antigen is frequently expressed on pancreatic cancer cells and can be targeted for immune-mediated destruction using CAR-modified, adoptively transferred T cells. The safety and efficacy of this approach indicate that it deserves further study and may represent a promising novel treatment for patients with pancreatic cancer. PMID:21843265

Control of invasive marine invertebrates: an experimental evaluation of the use of low salinity for managing pest corals (Tubastraea spp.).

PubMed

Moreira, Patrícia L; Ribeiro, Felipe V; Creed, Joel C

2014-01-01

This study investigated the use of low salinity as a killing agent for the invasive pest corals Tubastraea coccinea and Tubastraea tagusensis (Dendrophylliidae). Experiments investigated the efficacy of different salinities, the effect of colony size on susceptibility and the influence of length of exposure. Experimental treatments of colonies were carried out in aquaria. Colonies were then fixed onto experimental plates and monitored in the field periodically over a period of four weeks. The killing effectiveness of low salinity depended on the test salinity and the target species, but was independent of colony size. Low salinity was fast acting and prejudicial to survival: discoloration, necrosis, fragmenting and sloughing, exposure of the skeleton and cover by biofoulers occurred post treatment. For T. tagusensis, 50% mortality (LC50) after three days occurred at eight practical salinity units (PSU); for T. coccinea the LC50 was 2 PSU. Exposure to freshwater for 45-120 min resulted in 100% mortality for T. tagusensis, but only the 120 min period was 100% effective in killing T. coccinea. Freshwater is now routinely used for the post-border management of Tubastraea spp. This study also provides insights as to how freshwater may be used as a routine biosecurity management tool when applied pre-border to shipping vectors potentially transporting non-indigenous marine biofouling species.

Ribosome Display of Combinatorial Antibody Libraries Derived from Mice Immunized with Heat-Killed Xylella fastidiosa and the Selection of MopB-Specific Single-Chain Antibodies

PubMed Central

Azizi, Armaghan; Arora, Arinder; Markiv, Anatoliy; Lampe, David J.; Miller, Thomas A.

2012-01-01

Pierce's disease is a devastating lethal disease of Vitus vinifera grapevines caused by the bacterium Xylella fastidiosa. There is no cure for Pierce's disease, and control is achieved predominantly by suppressing transmission of the glassy-winged sharpshooter insect vector. We present a simple robust approach for the generation of panels of recombinant single-chain antibodies against the surface-exposed elements of X. fastidiosa that may have potential use in diagnosis and/or disease transmission blocking studies. In vitro combinatorial antibody ribosome display libraries were assembled from immunoglobulin transcripts rescued from the spleens of mice immunized with heat-killed X. fastidiosa. The libraries were used in a single round of selection against an outer membrane protein, MopB, resulting in the isolation of a panel of recombinant antibodies. The potential use of selected anti-MopB antibodies was demonstrated by the successful application of the 4XfMopB3 antibody in an enzyme-linked immunosorbent assay (ELISA), a Western blot assay, and an immunofluorescence assay (IFA). These immortalized in vitro recombinant single-chain antibody libraries generated against heat-killed X. fastidiosa are a resource for the Pierce's disease research community that may be readily accessed for the isolation of antibodies against a plethora of X. fastidiosa surface-exposed antigenic molecules. PMID:22327580

Comparative evaluation of recombinant LigB protein and heat-killed antigen-based latex agglutination test with microscopic agglutination test for diagnosis of bovine leptospirosis.

PubMed

Nagalingam, Mohandoss; Thirumalesh, Sushma Rahim Assadi; Kalleshamurthy, Triveni; Niharika, Nakkala; Balamurugan, Vinayagamurthy; Shome, Rajeswari; Sengupta, Pinaki Prasad; Shome, Bibek Ranjan; Prabhudas, Krishnamsetty; Rahman, Habibur

2015-10-01

This study aimed to develop latex agglutination test (LAT) using recombinant leptospiral immunoglobulin-like protein (LigB) (rLigB) antigen and compare its diagnostic efficacy with LAT using conventional heat-killed leptospiral antigen and microscopic agglutination test (MAT) in diagnosing bovine leptospirosis. The PCR-amplified 1053-bp ligB gene sequences from Leptospira borgpetersenii Hardjo serovar were cloned in pET 32 (a) vector at EcoRI and NotI sites and expressed in BL21 E. coli cells as fusion protein with thioredoxin (-57 kDa) and characterized by SDS-PAGE and immunoblot. Out of 390 serum samples [cattle (n = 214), buffaloes (n = 176)] subjected to MAT, 115 samples showed reciprocal titre≥100 up to 1600 against one or more serovars. For recombinant LigB protein/antigen-based LAT, agglutination was observed in the positive sample, while no agglutination was observed in the negative sample. Similarly, heat-killed leptospiral antigen was prepared from and used in LAT for comparison with MAT. A two-sided contingency table was used for analysis of LAT using both the antigens separately against MAT for 390 serum samples. The sensitivity, specificity and positive and negative predictive values of recombinant LigB LAT were found to be 75.65, 91.27, 78.38 and 89.96 %, respectively, and that of heat-killed antigen-based LAT were 72.17, 89.82, 74.77 and 88.53 %, respectively, in comparison with MAT. This developed test will be an alternative/complementary to the existing battery of diagnostic assays/tests for specific detection of pathogenic Leptospira infection in bovine population.

Cosmic acceleration from matter-curvature coupling

NASA Astrophysics Data System (ADS)

Zaregonbadi, Raziyeh; Farhoudi, Mehrdad

2016-10-01

We consider f( {R,T} ) modified theory of gravity in which, in general, the gravitational Lagrangian is given by an arbitrary function of the Ricci scalar and the trace of the energy-momentum tensor. We indicate that in this type of the theory, the coupling energy-momentum tensor is not conserved. However, we mainly focus on a particular model that matter is minimally coupled to the geometry in the metric formalism and wherein, its coupling energy-momentum tensor is also conserved. We obtain the corresponding Raychaudhuri dynamical equation that presents the evolution of the kinematic quantities. Then for the chosen model, we derive the behavior of the deceleration parameter, and show that the coupling term can lead to an acceleration phase after the matter dominated phase. On the other hand, the curvature of the universe corresponds with the deviation from parallelism in the geodesic motion. Thus, we also scrutinize the motion of the free test particles on their geodesics, and derive the geodesic deviation equation in this modified theory to study the accelerating universe within the spatially flat FLRW background. Actually, this equation gives the relative accelerations of adjacent particles as a measurable physical quantity, and provides an elegant tool to investigate the timelike and the null structures of spacetime geometries. Then, through the null deviation vector, we find the observer area-distance as a function of the redshift for the chosen model, and compare the results with the corresponding results obtained in the literature.

Climate Change and Vector Borne Diseases: Getting A Grip on Control

NASA Astrophysics Data System (ADS)

Glass, G. E.; Ellis, H.

2011-12-01

Pathogens that are transmitted by arthropods to humans kill millions of people a year and have long been identified as systems likely affected by climate change. Despite this, there has been a long controversy of how to evaluate the responses of these infectious disease systems to climatic conditions so that meaningful programmatic dcisions can be made. We briefly review the rationale for overall expectations, using them to identify both the temporal and spatial resolution needed for decision making and then discuss progress to date, using the world global malaria eradication program as an example.

Lactococcus lactis-based vaccines: current status and future perspectives.

PubMed

Bahey-El-Din, Mohammed; Gahan, Cormac G M

2011-01-01

Lactococcus lactis offers significant potential as a platform for the delivery of vaccines especially via mucosal routes of administration. The organism has an established history of safe use in the food industry and is highly amenable to genetic manipulation, with many systems available for efficient production of secreted and surface-expressed proteins. Here we describe the benefits of using this organism as a vaccine delivery platform and outline how L. lactis based antigen delivery may be improved. Finally we discuss the safe use of L. lactis vectors and outline the potential for use of biological containment systems and killed lactococcal preparations.

Aerospace Technologies of the 21st Century: New Technologies of Experimental Research and Simulation Held in Berlin, Germany on 8-9 June 2000

DTIC Science & Technology

2000-01-01

11. Gal-Or, B., U.S. PAT. Appl .. 08/516870/1, Aug. 18, 1995 & Isr. Pat. Appl . 113636, May 7,1995 by Gal- Or, Lichtsinder and Sherbaum.. 12. Gal-Or...B., U.S. PAT. Appl . 08/516870/2, Aug. 18, 1995 & Isr. Pat. Appl . 111265, Oct. 12,94 by Gal- Or, Lichtsinder and Sherbaum. 13. Gal-Or, B., U.S. PAT... Appl . 08/554087, Nov. 6,1995. 14. Gal-Or, B., ?Proposed Flight Testing Standards for Engine Thrust Vectoring to Maximize Kill Ra- tios, Post-Stall

BV-BFV approach to general relativity: Einstein-Hilbert action

NASA Astrophysics Data System (ADS)

Cattaneo, Alberto S.; Schiavina, Michele

2016-02-01

The present paper shows that general relativity in the Arnowitt-Deser-Misner formalism admits a BV-BFV formulation. More precisely, for any d + 1 ≠ 2 (pseudo-) Riemannian manifold M with space-like or time-like boundary components, the BV data on the bulk induces compatible BFV data on the boundary. As a byproduct, the usual canonical formulation of general relativity is recovered in a straightforward way.

From quarks and gluons to baryon form factors.

PubMed

Eichmann, Gernot

2012-04-01

I briefly summarize recent results for nucleon and [Formula: see text] electromagnetic, axial and transition form factors in the Dyson-Schwinger approach. The calculation of the current diagrams from the quark-gluon level enables a transparent discussion of common features such as: the implications of dynamical chiral symmetry breaking and quark orbital angular momentum, the timelike structure of the form factors, and their interpretation in terms of missing pion-cloud effects.

Energy-momentum restrictions on the creation of Gott time machines

NASA Astrophysics Data System (ADS)

Carroll, Sean M.; Farhi, Edward; Guth, Alan H.; Olum, Ken D.

1994-11-01

The discovery by Gott of a remarkably simple spacetime with closed timelike curves (CTC's) provides a tool for investigating how the creation of time machines is prevented in classical general relativity. The Gott spacetime contains two infinitely long, parallel cosmic strings, which can equivalently be viewed as point masses in (2+1)-dimensional gravity. We examine the possibility of building such a time machine in an open universe. Specifically, we consider initial data specified on an edgeless, noncompact, spacelike hypersurface, for which the total momentum is timelike (i.e., not the momentum of a Gott spacetime). In contrast to the case of a closed universe (in which Gott pairs, although not CTC's, can be produced from the decay of stationary particles), we find that there is never enough energy for a Gott-like time machine to evolve from the specified data; it is impossible to accelerate two particles to a sufficiently high velocity. Thus, the no-CTC theorems of Tipler and Hawking are enforced in an open (2+1)-dimensional universe by a mechanism different from that which operates in a closed universe. In proving our result, we develop a simple method to understand the inequalities that restrict the result of combining momenta in (2+1)-dimensional gravity.

Recombinant modified vaccinia virus Ankara–simian immunodeficiency virus gag pol elicits cytotoxic T lymphocytes in rhesus monkeys detected by a major histocompatibility complex class I/peptide tetramer

PubMed Central

Seth, Aruna; Ourmanov, Ilnour; Kuroda, Marcelo J.; Schmitz, Jörn E.; Carroll, Miles W.; Wyatt, Linda S.; Moss, Bernard; Forman, Meryl A.; Hirsch, Vanessa M.; Letvin, Norman L.

1998-01-01

The utility of modified vaccinia virus Ankara (MVA) as a vector for eliciting AIDS virus-specific cytotoxic T lymphocytes (CTL) was explored in the simian immunodeficiency virus (SIV)/rhesus monkey model. After two intramuscular immunizations with recombinant MVA-SIVSM gag pol, the monkeys developed a Gag epitope-specific CTL response readily detected in peripheral blood lymphocytes by using a functional killing assay. Moreover, those immunizations also elicited a population of CD8+ T lymphocytes in the peripheral blood that bound a specific major histocompatibility complex class I/peptide tetramer. These Gag epitope-specific CD8+ T lymphocytes also were demonstrated by using both functional and tetramer-binding assays in lymph nodes of the immunized monkeys. These observations suggest that MVA may prove a useful vector for an HIV-1 vaccine. They also suggest that tetramer staining may be a useful technology for monitoring CTL generation in vaccine trials in nonhuman primates and in humans. PMID:9707609

Improving the Cost-Effectiveness of Visual Devices for the Control of Riverine Tsetse Flies, the Major Vectors of Human African Trypanosomiasis

PubMed Central

Esterhuizen, Johan; Rayaisse, Jean Baptiste; Tirados, Inaki; Mpiana, Serge; Solano, Philippe; Vale, Glyn A.; Lehane, Michael J.; Torr, Stephen J.

2011-01-01

Control of the Riverine (Palpalis) group of tsetse flies is normally achieved with stationary artificial devices such as traps or insecticide-treated targets. The efficiency of biconical traps (the standard control device), 1×1 m black targets and small 25×25 cm targets with flanking nets was compared using electrocuting sampling methods. The work was done on Glossina tachinoides and G. palpalis gambiensis (Burkina Faso), G. fuscipes quanzensis (Democratic Republic of Congo), G. f. martinii (Tanzania) and G. f. fuscipes (Kenya). The killing effectiveness (measured as the catch per m2 of cloth) for small targets plus flanking nets is 5.5–15X greater than for 1 m2 targets and 8.6–37.5X greater than for biconical traps. This has important implications for the costs of control of the Riverine group of tsetse vectors of sleeping sickness. PMID:21829743

Identification of the ENT1 antagonists dipyridamole and dilazep as amplifiers of oncolytic herpes simplex virus-1 replication.

PubMed

Passer, Brent J; Cheema, Tooba; Zhou, Bingsen; Wakimoto, Hiroaki; Zaupa, Cecile; Razmjoo, Mani; Sarte, Jason; Wu, Shulin; Wu, Chin-lee; Noah, James W; Li, Qianjun; Buolamwini, John K; Yen, Yun; Rabkin, Samuel D; Martuza, Robert L

2010-05-15

Oncolytic herpes simplex virus-1 (oHSV) vectors selectively replicate in tumor cells, where they kill through oncolysis while sparing normal cells. One of the drawbacks of oHSV vectors is their limited replication and spread to neighboring cancer cells. Here, we report the outcome of a high-throughput chemical library screen to identify small-molecule compounds that augment the replication of oHSV G47Delta. Of the 2,640-screened bioactives, 6 compounds were identified and subsequently validated for enhanced G47Delta replication. Two of these compounds, dipyridamole and dilazep, interfered with nucleotide metabolism by potently and directly inhibiting the equilibrative nucleoside transporter-1 (ENT1). Replicative amplification promoted by dipyridamole and dilazep were dependent on HSV mutations in ICP6, the large subunit of ribonucleotide reductase. Our results indicate that ENT1 antagonists augment oHSV replication in tumor cells by increasing cellular ribonucleoside activity. (c)2010 AACR.

Investigation of spatiotemporal relationship between dengue fever and drought

NASA Astrophysics Data System (ADS)

Lee, Chieh-Han; Yu, Hwa-Lung

2016-04-01

Dengue Fever is a vector-borne disease that is transmitted between human and mosquitos in tropical and sub-tropical regions. Previous studies have found significant relationship between the epidemic of dengue cases and climate variables, especially temperature and precipitation. Besides, the natural phenomena (e.g., drought) are considered that significantly drop the number of dengue cases by killing vector's breeding environment. However, in Kaohsiung City, Taiwan, there are evidences that the temporal pattern of dengue is correlated to drought events. Kaohsiung City experienced two main dengue outbreaks in 2002 and 2014 that both years were confirmed with serious drought. Especially in 2014, Kaohsiung City was suffered from extremely dengue outbreak in 2014 that reported the highest number of dengue cases in the history. Otherwise, another nearby city, Tainan City, had reported the biggest outbreak in 2015. This study constructs the spatiotemporal model of dengue incidences and index of drought events (Standardized Precipitation Index, SPI) based on the distributed lag nonlinear model (DLNM). Other meteorological measures are also included in the analysis.

Spin-dependent post-Newtonian parameters from EMRI computation in Kerr background

NASA Astrophysics Data System (ADS)

Friedman, John; Le Tiec, Alexandre; Shah, Abhay

2013-04-01

Because the extreme mass-ratio inspiral (EMRI) approximation is accurate to all orders in v/c, it can be used to find high order post-Newtonian parameters that are not yet analytically accessible. We report here on progress in computing spin-dependent, conservative, post-Newtonian parameters from a radiation-gauge computation for a particle in circular orbit in a family of Kerr geometries. For a particle with 4-velocity u^α= U k^α, with k^α the helical Killing vector of the perturbed spacetime, the renormalized perturbation δU, when written as a function of the particle's angular velocity, is invariant under gauge transformations generated by helically symmetric vectors. The EMRI computations are done in a modified radiation gauge. Extracted parameters are compared to previously known and newly computed spin-dependent post-Newtonian terms. This work is modeled on earlier computations by Blanchet, Detweiler, Le Tiec and Whiting of spin-independent terms for a particle in circular orbit in a Schwarzschild geometry.

Killing approximation for vacuum and thermal stress-energy tensor in static space-times

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frolov, V.P.; Zel'nikov, A.I.

1987-05-15

The problem of the vacuum polarization of conformal massless fields in static space-times is considered. A tensor T/sub ..mu..//sub ..nu../ constructed from the curvature, the Killing vector, and their covariant derivatives is proposed which can be used to approximate the average value of the stress-energy tensor /sup ren/ in such spaces. It is shown that if (i) its trace T /sub epsilon//sup epsilon/ coincides with the trace anomaly /sup ren/, (ii) it satisfies the conservation law T/sup ..mu..//sup epsilon/ /sub ;//sub epsilon/ = 0, and (iii) it has the correct behavior under the scale transformations, then it is uniquely definedmore » up to a few arbitrary constants. These constants must be chosen to satisfy the boundary conditions. In the case of a static black hole in a vacuum these conditions single out the unique tensor T/sub ..mu..//sub ..nu../ which provides a good approximation for /sup ren/ in the Hartle-Hawking vacuum. The relation between this approach and the Page-Brown-Ottewill approach is discussed.« less

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

PubMed

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

2014-01-01

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. 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. 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. 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.

A Multiscale Model for the World's First Parasitic Disease Targeted for Eradication: Guinea Worm Disease

PubMed Central

Netshikweta, Rendani

2017-01-01

Guinea worm disease (GWD) is both a neglected tropical disease and an environmentally driven infectious disease. Environmentally driven infectious diseases remain one of the biggest health threats for human welfare in developing countries and the threat is increased by the looming danger of climate change. In this paper we present a multiscale model of GWD that integrates the within-host scale and the between-host scale. The model is used to concurrently examine the interactions between the three organisms that are implicated in natural cases of GWD transmission, the copepod vector, the human host, and the protozoan worm parasite (Dracunculus medinensis), and identify their epidemiological roles. The results of the study (through sensitivity analysis of R0) show that the most efficient elimination strategy for GWD at between-host scale is to give highest priority to copepod vector control by killing the copepods in drinking water (the intermediate host) by applying chemical treatments (e.g., temephos, an organophosphate). This strategy should be complemented by health education to ensure that greater numbers of individuals and communities adopt behavioural practices such as voluntary reporting of GWD cases, prevention of GWD patients from entering drinking water bodies, regular use of water from safe water sources, and, in the absence of such water sources, filtering or boiling water before drinking. Taking into account the fact that there is no drug or vaccine for GWD (interventions which operate at within-host scale), the results of our study show that the development of a drug that kills female worms at within-host scale would have the highest impact at this scale domain with possible population level benefits that include prevention of morbidity and prevention of transmission. PMID:28808479

The Long and Winding Road: From the High-Affinity Choline Uptake Site to Clinical Trials for Malignant Brain Tumors.

PubMed

Lowenstein, P R; Castro, M G

2016-01-01

Malignant brain tumors are one of the most lethal cancers. They originate from glial cells which infiltrate throughout the brain. Current standard of care involves surgical resection, radiotherapy, and chemotherapy; median survival is currently ~14-20 months postdiagnosis. Given that the brain immune system is deficient in priming systemic immune responses to glioma antigens, we proposed to reconstitute the brain immune system to achieve immunological priming from within the brain. Two adenoviral vectors are injected into the resection cavity or remaining tumor. One adenoviral vector expresses the HSV-1-derived thymidine kinase which converts ganciclovir into a compound only cytotoxic to dividing glioma cells. The second adenovirus expresses the cytokine fms-like tyrosine kinase 3 ligand (Flt3L). Flt3L differentiates precursors into dendritic cells and acts as a chemokine that attracts dendritic cells to the brain. HSV-1/ganciclovir killing of tumor cells releases tumor antigens that are taken up by dendritic cells within the brain tumor microenvironment. Tumor killing also releases HMGB1, an endogenous TLR2 agonist that activates dendritic cells. HMGB1-activated dendritic cells, loaded with glioma antigens, migrate to cervical lymph nodes to stimulate a systemic CD8+ T cells cytotoxic immune response against glioma. This immune response is specific to glioma tumors, induces immunological memory, and does neither cause brain toxicity nor autoimmune responses. An IND was granted by the FDA on 4/7/2011. A Phase I, first in person trial, to test whether reengineering the brain immune system is potentially therapeutic is ongoing. © 2016 Elsevier Inc. All rights reserved.

Conserved charge of a gravity theory with p -form gauge fields and its property under Kaluza-Klein reduction

NASA Astrophysics Data System (ADS)

Peng, Jun-Jin

2017-05-01

In this paper, we investigate the conserved charges of generally diffeomorphism invariant gravity theories with a wide variety of matter fields, particularly of the theories with multiple scalar fields and p -form potentials, in the context of the off-shell generalized Abbott-Deser-Tekin (ADT) formalism. We first construct a new off-shell ADT current that consists of the terms for the variation of a Killing vector and expressions of the field equations as well as the Lie derivative of a surface term with respect to the Killing vector within the framework of generally diffeomorphism invariant gravity theories involving various matter fields. After deriving the off-shell ADT potential corresponding to this current, we propose a formula of conserved charges for these theories. Next, we derive the off-shell ADT potential associated with the generic Lagrangian that describes a large range of gravity theories with a number of scalar fields and p -form potentials. Finally, the properties of the off-shell generalized ADT charges for the theory of Einstein gravity and the gravity theories with a single p -form potential are investigated by performing Kaluza-Klein dimensional reduction along a compactified direction. The results indicate that the charge contributed by all the fields in the lower-dimensional theory is equal to that of the higher-dimensional one at mathematical level with the hypothesis that the higher-dimensional spacetime allows for the existence of the compactified dimension. In order to illustrate our calculations, the mass and angular momentum for the five-dimensional rotating Kaluza-Klein black holes are explicitly evaluated as an example.

Rapidly moving cosmic strings and chronology protection

NASA Astrophysics Data System (ADS)

Ori, Amos

1991-10-01

Recently, Gott has provided a family of solutions of the Einstein equations describing pairs of parallel cosmic strings in motion. He has shown that if the strings' relative velocity is sufficiently high, there exist closed timelike curves (CTC's) in the spacetime. Here we show that if there are CTC's in such a solution, then every t=const hypersurface in the spacetime intersects CTC's. Therefore, these solutions do not contradict the chronology protection conjecture of Hawking.

From quarks and gluons to baryon form factors

PubMed Central

Eichmann, Gernot

2012-01-01

I briefly summarize recent results for nucleon and Δ(1232) electromagnetic, axial and transition form factors in the Dyson–Schwinger approach. The calculation of the current diagrams from the quark–gluon level enables a transparent discussion of common features such as: the implications of dynamical chiral symmetry breaking and quark orbital angular momentum, the timelike structure of the form factors, and their interpretation in terms of missing pion-cloud effects. PMID:26766879

Triple collinear emissions in parton showers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Höche, Stefan; Prestel, Stefan

2017-10-01

A framework to include triple collinear splitting functions into parton showers is presented, and the implementation of flavor-changing NLO splitting kernels is discussed as a first application. The correspondence between the Monte-Carlo integration and the analytic computation of NLO DGLAP evolution kernels is made explicit for both timelike and spacelike parton evolution. Numerical simulation results are obtained with two independent implementations of the new algorithm, using the two independent event generation frameworks Pythia and Sherpa.

Conditional Cytotoxic Anti-HIV Gene Therapy for Selectable Cell Modification

PubMed Central

Garg, Himanshu; Joshi, Anjali

2016-01-01

Gene therapy remains one of the potential strategies to achieve a cure for HIV infection. One of the major limitations of anti-HIV gene therapy concerns recovering an adequate number of modified cells to generate an HIV-proof immune system. Our study addresses this issue by developing a methodology that can mark conditional vector-transformed cells for selection and subsequently target HIV-infected cells for elimination by treatment with ganciclovir (GCV). We used the herpes simplex virus thymidine kinase (TK) mutant SR39, which is highly potent at killing cells at low GCV concentrations. This gene was cloned into a conditional HIV vector, pNL-GFPRRESA, which expresses the gene of interest as well as green fluorescent protein (GFP) in the presence of HIV Tat protein. We show here that TK-SR39 was more potent that wild-type TK (TK-WT) at eliminating infected cells at lower concentrations of GCV. As the vector expresses GFP in the presence of Tat, transient expression of Tat either by Tat RNA transfection or transduction by a nonintegrating lentiviral (NIL) vector marked the cells with GFP for selection. In cells selected by this strategy, TK-SR39 was more potent at limiting virus replication than TK-WT. Finally, in Jurkat cells modified and selected by this approach, infection with CXCR4-tropic Lai virus could be suppressed by treatment with GCV. GCV treatment limited the number of HIV-infected cells, virus production, as well as virus-induced cytopathic effects in this model. We provide proof of principle that TK-SR39 in a conditional HIV vector can provide a safe and effective anti-HIV strategy. PMID:26800572

The abundance of the Lyme disease pathogen Borrelia afzelii declines over time in the tick vector Ixodes ricinus.

PubMed

Jacquet, Maxime; Genné, Dolores; Belli, Alessandro; Maluenda, Elodie; Sarr, Anouk; Voordouw, Maarten J

2017-05-25

The population dynamics of vector-borne pathogens inside the arthropod vector can have important consequences for vector-to-host transmission. Tick-borne spirochete bacteria of the Borrelia burgdorferi (sensu lato) species complex cause Lyme borreliosis in humans and spend long periods of time (>12 months) in their Ixodes tick vectors. To date, few studies have investigated the dynamics of Borrelia spirochete populations in unfed Ixodes nymphal ticks. Larval ticks from our laboratory colony of I. ricinus were experimentally infected with B. afzelii, and killed at 1 month and 4 months after the larva-to-nymph moult. The spirochete load was also compared between engorged larval ticks and unfed nymphs (from the same cohort) and between unfed nymphs and unfed adult ticks (from the same cohort). The spirochete load of B. afzelii in each tick was estimated using qPCR. The mean spirochete load in the 1-month-old nymphs (~14,000 spirochetes) was seven times higher than the 4-month-old nymphs (~2000 spirochetes). Thus, the nymphal spirochete load declined by 80% over a period of 3 months. An engorged larval tick acquired ~100 spirochetes, and this population was 20 times larger in a young, unfed nymph. The spirochete load also appeared to decline in adult ticks. Comparison between wild and laboratory populations found that lab ticks were more susceptible to acquiring B. afzelii. The spirochete load of B. afzelii declines dramatically over time in domesticated I. ricinus nymphs under laboratory conditions. Future studies should investigate whether temporal declines in spirochete load occur in wild Ixodes ticks under natural conditions and whether these declines influence the tick-to-host transmission of Borrelia.

Conditional Cytotoxic Anti-HIV Gene Therapy for Selectable Cell Modification.

PubMed

Garg, Himanshu; Joshi, Anjali

2016-05-01

Gene therapy remains one of the potential strategies to achieve a cure for HIV infection. One of the major limitations of anti-HIV gene therapy concerns recovering an adequate number of modified cells to generate an HIV-proof immune system. Our study addresses this issue by developing a methodology that can mark conditional vector-transformed cells for selection and subsequently target HIV-infected cells for elimination by treatment with ganciclovir (GCV). We used the herpes simplex virus thymidine kinase (TK) mutant SR39, which is highly potent at killing cells at low GCV concentrations. This gene was cloned into a conditional HIV vector, pNL-GFPRRESA, which expresses the gene of interest as well as green fluorescent protein (GFP) in the presence of HIV Tat protein. We show here that TK-SR39 was more potent that wild-type TK (TK-WT) at eliminating infected cells at lower concentrations of GCV. As the vector expresses GFP in the presence of Tat, transient expression of Tat either by Tat RNA transfection or transduction by a nonintegrating lentiviral (NIL) vector marked the cells with GFP for selection. In cells selected by this strategy, TK-SR39 was more potent at limiting virus replication than TK-WT. Finally, in Jurkat cells modified and selected by this approach, infection with CXCR4-tropic Lai virus could be suppressed by treatment with GCV. GCV treatment limited the number of HIV-infected cells, virus production, as well as virus-induced cytopathic effects in this model. We provide proof of principle that TK-SR39 in a conditional HIV vector can provide a safe and effective anti-HIV strategy.

Targeting male mosquito swarms to control malaria vector density

PubMed Central

Sawadogo, Simon Peguedwinde; Niang, Abdoulaye; Bilgo, Etienne; Millogo, Azize; Maïga, Hamidou; Dabire, Roch K.; Tripet, Frederic; Diabaté, Abdoulaye

2017-01-01

Malaria control programs are being jeopardized by the spread of insecticide resistance in mosquito vector populations. It has been estimated that the spread of resistance could lead to an additional 120000 deaths per year, and interfere with the prospects for sustained control or the feasibility of achieving malaria elimination. Another complication for the development of resistance management strategies is that, in addition to insecticide resistance, mosquito behavior evolves in a manner that diminishes the impact of LLINs and IRS. Mosquitoes may circumvent LLIN and IRS control through preferential feeding and resting outside human houses and/or being active earlier in the evening before people go to sleep. Recent developments in our understanding of mosquito swarming suggest that new tools targeting mosquito swarms can be designed to cut down the high reproductive rate of malaria vectors. Targeting swarms of major malaria vectors may provide an effective control method to counteract behavioral resistance developed by mosquitoes. Here, we evaluated the impact of systematic spraying of swarms of Anopheles gambiae s.l. using a mixed carbamate and pyrethroid aerosol. The impact of this intervention on vector density, female insemination rates and the age structure of males was measured. We showed that the resulting mass killing of swarming males and some mate-seeking females resulted in a dramatic 80% decrease in population size compared to a control population. A significant decrease in female insemination rate and a significant shift in the age structure of the male population towards younger males incapable of mating were observed. This paradigm-shift study therefore demonstrates that targeting primarily males rather than females, can have a drastic impact on mosquito population. PMID:28278212

Efficiency Evaluation of Nozawa-Style Black Light Trap for Control of Anopheline Mosquitoes

PubMed Central

Lee, Hee Il; Seo, Bo Youl; Shin, E-Hyun; Burkett, Douglas A.; Lee, Jong-Koo

2009-01-01

House-residual spraying and insecticide-treated bed nets have achieved some success in controlling anthropophilic and endophagic vectors. However, these methods have relatively low efficacy in Korea because Anopheles sinensis, the primary malaria vector, is highly zoophilic and exophilic. So, we focused our vector control efforts within livestock enclosures using ultraviolet black light traps as a mechanical control measure. We found that black light traps captured significantly more mosquitoes at 2 and 2.5 m above the ground (P < 0.05). We also evaluated the effectiveness of trap spacing within the livestock enclosure. In general, traps spaced between 4 and 7 m apart captured mosquitoes more efficiently than those spaced closer together (P > 0.05). Based on these findings, we concluded that each black light trap in the livestock enclosures killed 7,586 female mosquitoes per trap per night during the peak mosquito season (July-August). In May-August 2003, additional concurrent field trials were conducted in Ganghwa county. We got 74.9% reduction (P < 0.05) of An. sinensis in human dwellings and 61.5% reduction (P > 0.05) in the livestock enclosures. The black light trap operation in the livestock enclosures proved to be an effective control method and should be incorporated into existing control strategies in developed countries. PMID:19488423

Larvicidal efficacy screening of Anacardaciae crude extracts on the dengue hemorrhagic vector, Aedes aegypti.

PubMed

Zuharah, W F; Fadzly, N; Ali, Y; Zakaria, R; Juperi, S; Asyraf, M; Dieng, H

2014-06-01

Vector-borne diseases are still rife because of the re-emergence of diseases transmitted by mosquitoes. The objective of this paper is to evaluate the larvicidal efficacy of crude leaf extract of Mangifera indica, Gluta renghas, and Melanochyla fasciculiflora against vector of dengue hemorrhagic fever, Aedes aegypti. These plant species are endemic species and widely distributed in Malaysian forests. Leaves of Ma. indica, G. renghas and M. fascculiflora were collected from Teluk Bahang National Park, Penang Malaysia. Fractions of leaves were segregated, air-dried, powdered and extracted using Soxhlet with methanol. The solvent was removed by using rotary evaporator to obtain the crude extract. Using WHO standard larval bioassay test method, third instar larvae of Aedes aegypti were exposed to concentration ranging from 200- 4500 ppm of methanol extract for all plant species. Larval mortality was observed after 24 hours exposure. The highest susceptibility and toxicity was recorded by Mangifera indica with the lowest concentration at 800 ppm followed by M. fasciculiflora and G. renghas. This indicates that crude plant extract is very effective in killing Ae. aegypti mosquitoes. This finding may lead to new low cost alternative, environmentally friendly method for mosquito control programs. To our knowledge, this is the first report on larvicidal bioefficacy from endemic Malaysian plants.

EGFR-targeted granzyme B expressed in NK cells enhances natural cytotoxicity and mediates specific killing of tumor cells.

PubMed

Oberoi, Pranav; Jabulowsky, Robert A; Bähr-Mahmud, Hayat; Wels, Winfried S

2013-01-01

Natural killer (NK) cells are highly specialized effectors of the innate immune system that hold promise for adoptive cancer immunotherapy. Their cell killing activity is primarily mediated by the pro-apoptotic serine protease granzyme B (GrB), which enters targets cells with the help of the pore-forming protein perforin. We investigated expression of a chimeric GrB fusion protein in NK cells as a means to augment their antitumoral activity. For selective targeting to tumor cells, we fused the epidermal growth factor receptor (EGFR) peptide ligand transforming growth factor α (TGFα) to human pre-pro-GrB. Established human NKL natural killer cells transduced with a lentiviral vector expressed this GrB-TGFα (GrB-T) molecule in amounts comparable to endogenous wildtype GrB. Activation of the genetically modified NK cells by cognate target cells resulted in the release of GrB-T together with endogenous granzymes and perforin, which augmented the effector cells' natural cytotoxicity against NK-sensitive tumor cells. Likewise, GrB-T was released into the extracellular space upon induction of degranulation with PMA and ionomycin. Secreted GrB-T fusion protein displayed specific binding to EGFR-overexpressing tumor cells, enzymatic activity, and selective target cell killing in the presence of an endosomolytic activity. Our data demonstrate that ectopic expression of a targeted GrB fusion protein in NK cells is feasible and can enhance antitumoral activity of the effector cells.

Innate immunity is not related to the sex of adult Tree Swallows during the nestling period

USGS Publications Warehouse

Houdek, Bradley J.; Lombardo, Michael P.; Thorpe, Patrick A.; Hahn, D. Caldwell

2011-01-01

Evolutionary theory predicts that exposure to more diverse pathogens will result in the evolution of a more robust immune response. We predicted that during the breeding season the innate immune function of female Tree Swallows (Tachycineta bicolor) should be more effective than that of males because (1) the transmission of sexually transmitted microbes during copulation puts females at greater risk because ejaculates move from males to females, (2) females copulate with multiple males, exposing them to the potentially pathogenic microbes in semen, and (3) females spend more time in the nest than do males so may be more exposed to nest microbes and ectoparasites that can be vectors of bacterial and viral pathogens. In addition, elevated testosterone in males may suppress immune function. We tested our prediction during the 2009 breeding season with microbicidal assays in vitro to assess the ability of the innate immune system to kill Escherichia coli. The sexes did not differ in the ability of their whole blood to kill E. coli. We also found no significant relationships between the ability of whole blood to kill E. coli and the reproductive performance or the physical condition of males or females. These results indicate that during the nestling period there are no sexual differences in this component of the innate immune system. In addition, they suggest that there is little association between this component of innate immunity and the reproductive performance and physical condition during the nestling period of adult Tree Swallows.

Ivermectin susceptibility, sporontocidal effect, and inhibition of time to re-feed in the Amazonian malaria vector Anopheles darlingi.

PubMed

Kobylinski, Kevin C; Escobedo-Vargas, Karín S; López-Sifuentes, Victor M; Durand, Salomón; Smith, Edward S; Baldeviano, G Christian; Gerbasi, Robert V; Ballard, Sara-Blythe; Stoops, Craig A; Vásquez, Gissella M

2017-11-21

Outdoor malaria transmission hinders malaria elimination efforts in the Amazon region and novel vector control tools are needed. Ivermectin mass drug administration (MDA) to humans kills wild Anopheles, targets outdoor-feeding vectors, and can suppress malaria parasite transmission. Laboratory investigations were performed to determine ivermectin susceptibility, sporontocidal effect and inhibition of time to re-feed for the primary Amazonian malaria vector, Anopheles darlingi. To assess ivermectin susceptibility, various concentrations of ivermectin were mixed in human blood and fed to An. darlingi. Mosquito survival was monitored daily for 7 days and a non-linear mixed effects model with Probit analysis was used to calculate lethal concentrations of ivermectin that killed 50% (LC 50 ), 25% (LC 25 ) and 5% (LC 5 ) of mosquitoes. To examine ivermectin sporonticidal effect, Plasmodium vivax blood samples were collected from malaria patients and offered to mosquitoes without or with ivermectin at the LC 50 , LC 25 or LC 5 . To assess ivermectin inhibition of mosquito time to re-feed, concentrations of ivermectin predicted to occur after a single oral dose of 200 μg/kg ivermectin were fed to An. darlingi. Every day for 12 days thereafter, individual mosquitoes were given the opportunity to re-feed on a volunteer. Any mosquitoes that re-blood fed or died were removed from the study. Ivermectin significantly reduced An. darlingi survivorship: 7-day-LC 50  = 43.2 ng/ml [37.5, 48.6], -LC 25  = 27.8 ng/ml [20.4, 32.9] and -LC 5  = 14.8 ng/ml [7.9, 20.2]. Ivermectin compound was sporontocidal to P. vivax in An. darlingi at the LC 50 and LC 25 concentrations reducing prevalence by 22.6 and 17.1%, respectively, but not at the LC 5 . Oocyst intensity was not altered at any concentration. Ivermectin significantly delayed time to re-feed at the 4-h (48.7 ng/ml) and 12-h (26.9 ng/ml) concentrations but not 36-h (10.6 ng/ml) or 60-h (6.3 ng/ml). Ivermectin is lethal to An. darlingi, modestly inhibits sporogony of P. vivax, and delays time to re-feed at concentrations found in humans up to 12 h post drug ingestion. The LC 50 value suggests that a higher than standard dose (400-μg/kg) is necessary to target An. darlingi. These results suggest that ivermectin MDA has potential in the Amazon region to aid malaria elimination efforts.

Gene therapy for human ovarian cancer cells using efficient expression of Fas gene combined with γδT cells.

PubMed

Lin, Jiajing; Zeng, Dingyuan; He, Hongying; Tan, Guangping; Lan, Ying; Jiang, Fuyan; Sheng, Shuting

2017-10-01

Low tissue specificity and efficiency of exogenous gene expression are the two major obstacles in tumor‑targeted gene therapy. The Fas cell surface death receptor (Fas)/Fas ligand pathway is one of the primary pathways responsible for the regulation of cell apoptosis. The aim of the present study was to explore whether the regulation of tumor specific promoters and a two‑step transcriptional amplification system (TSTA) assured efficient, targeted expression of their downstream Fas gene in human ovarian cancer cells, and to assess the killing effect of γδT cells on these cells with high Fas expression. Three shuttle plasmids containing different control elements of the human telomerase reverse transcriptase (hTERT) promoter and/or TSTA were constructed and packaged into adenovirus 5 (Ad5) vectors for the expression of exogenous Fas gene. The human ovarian cancer cell line SKOV3 and a control human embryonic lung fibroblast cell line were transfected with Ad5‑hTERT‑Fas or Ad5‑hTERT‑TSTA‑Fas. Fas mRNA and protein expression were examined by reverse transcription‑quantitative polymerase chain reaction and western blot analysis. γδT lymphocytes were isolated, cultured and mixed at different ratios with SKOV3 cells with Fas expression in order to assess the killing effect of γδT cells. hTERT promoter induced the specific expression of FAS gene in SKOV3 cells, and the TSTA strategy increased FAS expression by 14.2‑fold. The killing effect of γδT cells increased with the expression level of Fas and the effector‑target cell ratio. The killing rate for SKOV3 cells with high FAS expression was 72.5% at an effector‑target cell ratio of 40:1. The regulators of hTERT promoter and TSTA assure the efficient and targeted expression of their downstream Fas gene in SKOV3 cells. The killing effect of γδT cells for ovarian cancer cells with relatively high Fas expression was improved.

[Hypoxia responsive element regulated herpes simplex virus-thymidine kinase system enhances killing effect of gancyclovir on Ewing's sarcoma cell line under hypoxic condition].

PubMed

Si, Ying-jian; Guang, Li-xia; Yuan, Fa-huan; Zhang, Ke-bin

2006-08-01

To find out a possible approach to improve the effectiveness of radiotherapy and chemotherapy for Ewing's sarcoma by constructing a eukaryotic expression vector expressing herpes simplex virus-thymidine kinase (HSV-TK) regulated by hypoxia responsive element (HRE) under hypoxia and to evaluate the effects of this HRE regulated HSV-TK system on killing effect of gancyclovir (GCV) on Ewing's sarcoma cell line SK-ES under hypoxic condition. The HRE was synthesized according to the literature and cloned into the enhancer site of pIRES(2)-EGFP vector to obtain the pHRE recombinant plasmid. The HSV-TK was amplified by PCR and cloned into the multiple clone site of pIRES(2)-EGFP and pHRE to obtain pTK and pHRE-TK recombinant plasmid. The human Ewing's sarcoma cell line SK-ES was transfected by pTK or pHRE-TK recombinant plasmid with liposome and then was exposed to normoxic (21% oxygen) or hypoxic (3% oxygen) condition. The expression of enhanced green fluorescent protein (EGFP) was monitored by fluorescent microscopy. The sensitivity of human Ewing's sarcoma cell line SK-ES transfected with pTK or pHRE-TK recombinant plasmid to the anti-tumour drug GCV was determined with the method of tetrazolium (MTT) after treating with GCV for five days. (1) The result of sequencing showed that the recombinant plasmid pHRE contained HRE, and that the recombinant plasmid pTK and pHRE-TK contained HSV-TK gene in the sense direction. (2) Comparison of fluorescent optical density (FOD) showed that (1) the EGFP FOD value of pHRE and pHRE-TK group cells exposed to hypoxia was significantly higher than those exposed to normoxia (P < 0.01); (2) when the cells were exposed to hypoxia, the EGFP FOD value of pHRE and pHRE-TK group cells was significantly higher than that of pTK and empty vector group (P < 0.01); (3) there was no significant difference among the four groups of cells when they were exposed to normoxia (P > 0.05). (3) Comparison of the sensitivity of four groups of cells to GCV showed that (1) the cells in pHRE-TK and pTK groups were much more sensitive to GCV than the cells in pHRE group under hypoxia condition (P < 0.01), the higher the GCV concentration, the greater the difference; (2) the cells of pHRE-TK group were more sensitive to GCV than those in pTK group under hypoxic condition (P < 0.01), but was almost equally sensitive under normoxic condition (P > 0.05); (3) the pHRE-TK group cells had higher sensitivity to GCV under hypoxia than normoxia (P < 0.01) while the pTK group cells had almost the same sensitivity to GCV under hypoxia and normoxia (P > 0.05). (1) The eukaryotic expression vector expressing herpes simplex virus-thymidine kinase (HSV-TK) regulated by hypoxia responsive element (HRE) under hypoxia was constructed successfully. (2) HRE could up-regulate expression of EGFP by SK-ES cells under hypoxia condition. (3) HRE could enhance the killing effect of HSV-TK/GCV system on human Ewing's sarcoma cell line SK-ES under hypoxic condition.

Parasite killing in malaria non-vector mosquito Anopheles culicifacies species B: implication of nitric oxide synthase upregulation.

PubMed

Vijay, Sonam; Rawat, Manmeet; Adak, Tridibes; Dixit, Rajnikant; Nanda, Nutan; Srivastava, Harish; Sharma, Joginder K; Prasad, Godavarthi B K S; Sharma, Arun

2011-04-04

Anopheles culicifacies, the main vector of human malaria in rural India, is a complex of five sibling species. Despite being phylogenetically related, a naturally selected subgroup species B of this sibling species complex is found to be a poor vector of malaria. We have attempted to understand the differences between vector and non-vector Anopheles culicifacies mosquitoes in terms of transcriptionally activated nitric oxide synthase (AcNOS) physiologies to elucidate the mechanism of refractoriness. Identification of the differences between genes and gene products that may impart refractory phenotype can facilitate development of novel malaria transmission blocking strategies. We conducted a study on phylogenetically related susceptible (species A) and refractory (species B) sibling species of An. culicifacies mosquitoes to characterize biochemical and molecular differences in AcNOS gene and gene elements and their ability to inhibit oocyst growth. We demonstrate that in species B, AcNOS specific activity and nitrite/nitrates in mid-guts and haemolymph were higher as compared to species A after invasion of the mid-gut by P. vivax at the beginning and during the course of blood feeding. Semiquantitative RT-PCR and real time PCR data of AcNOS concluded that this gene is more abundantly expressed in midgut of species B than in species A and is transcriptionally upregulated post blood meals. Dietary feeding of L-NAME along with blood meals significantly inhibited midgut AcNOS activity leading to an increase in oocyst production in An. culicifacies species B. We hypothesize that upregulation of mosquito innate cytotoxicity due to NOS in refractory strain to Plasmodium vivax infection may contribute to natural refractoriness in An. culicifacies mosquito population. This innate capacity of refractory mosquitoes could represent the ancestral function of the mosquito immune system against the parasite and could be utilized to understand the molecular basis of refractoriness in planning effective vector control strategies.

Parasite Killing in Malaria Non-Vector Mosquito Anopheles culicifacies Species B: Implication of Nitric Oxide Synthase Upregulation

PubMed Central

Vijay, Sonam; Rawat, Manmeet; Adak, Tridibes; Dixit, Rajnikant; Nanda, Nutan; Srivastava, Harish; Sharma, Joginder K.; Prasad, Godavarthi B. K. S.; Sharma, Arun

2011-01-01

Background Anopheles culicifacies, the main vector of human malaria in rural India, is a complex of five sibling species. Despite being phylogenetically related, a naturally selected subgroup species B of this sibling species complex is found to be a poor vector of malaria. We have attempted to understand the differences between vector and non-vector Anopheles culicifacies mosquitoes in terms of transcriptionally activated nitric oxide synthase (AcNOS) physiologies to elucidate the mechanism of refractoriness. Identification of the differences between genes and gene products that may impart refractory phenotype can facilitate development of novel malaria transmission blocking strategies. Methodology/Principal Findings We conducted a study on phylogenetically related susceptible (species A) and refractory (species B) sibling species of An. culicifacies mosquitoes to characterize biochemical and molecular differences in AcNOS gene and gene elements and their ability to inhibit oocyst growth. We demonstrate that in species B, AcNOS specific activity and nitrite/nitrates in mid-guts and haemolymph were higher as compared to species A after invasion of the mid-gut by P. vivax at the beginning and during the course of blood feeding. Semiquantitative RT-PCR and real time PCR data of AcNOS concluded that this gene is more abundantly expressed in midgut of species B than in species A and is transcriptionally upregulated post blood meals. Dietary feeding of L-NAME along with blood meals significantly inhibited midgut AcNOS activity leading to an increase in oocyst production in An. culicifacies species B. Conclusions/Significance We hypothesize that upregulation of mosquito innate cytotoxicity due to NOS in refractory strain to Plasmodium vivax infection may contribute to natural refractoriness in An. culicifacies mosquito population. This innate capacity of refractory mosquitoes could represent the ancestral function of the mosquito immune system against the parasite and could be utilized to understand the molecular basis of refractoriness in planning effective vector control strategies. PMID:21483693

Conformal gravity and time

NASA Astrophysics Data System (ADS)

Hazboun, Jeffrey Shafiq

2014-10-01

Cartan geometry provides a rich formalism from which to look at various geometrically motivated extensions to general relativity. In this manuscript, we start by motivating reasons to extend the theory of general relativity. We then introduce the reader to our technique, called the quotient manifold method, for extending the geometry of spacetime. We will specifically look at the class of theories formed from the various quotients of the conformal group. Starting with the conformal symmetries of Euclidean space, we construct a manifold where time manifests as a part of the geometry. Though there is no matter present in the geome- try studied here, geometric terms analogous to dark energy and dark matter appear when we write down the Einstein tensor. Specifically, the quotient of the conformal group of Euclidean four-space by its Weyl subgroup results in a geometry possessing many of the properties of relativistic phase space, including both a natural symplectic form and nondegenerate Killing metric. We show the general solution possesses orthogonal Lagrangian submanifolds, with the induced metric and the spin connection on the submanifolds necessarily Lorentzian, despite the Euclidean starting point. By examining the structure equations of the biconformal space in an orthonormal frame adapted to its phase space properties, we also find two new tensor fields exist in this geometry, not present in Riemannian geometry. The first is a combination of the Weyl vector with the scale factor on the metric, and determines the time-like directions on the submanifolds. The second comes from the components of the spin connection, symmetric with respect to the new metric. Though this field comes from the spin connection, it transforms ho- mogeneously. Finally, we show in the absence of Cartan curvature or sources, the configuration space has geometric terms equivalent to a perfect fluid and a cosmological constant. We complete the analysis of this homogeneous space by transforming the known, general solution of the Maurer-Cartan equations into the orthogonal, Lagrangian basis. This results in a signature-changing metric, just as in the work of Spencer and Wheeler, however without any conditions on the curvature of the momentum sector. The Riemannian curvatures of the two submanifolds are directly related. We investigate the case where the curvature on the momentum submanifold vanishes, while the curvature of the configuration submanifold gives an effective energy-momentum tensor corresponding to a perfect fluid. In the second part of this manuscript, we look at the most general curved biconformal geometry dictated by the Wehner-Wheeler action. We use the assemblage of structure equations, Bianchi identities, and field equations to show how the geometry of the manifolds self-organizes into trivial Weyl geometries, which can then be gauged to Riemannian geometries. The Bianchi identities reveal the strong relationships between the various curvatures, torsions, and cotorsions. The discussion of the curved case culminates in a number of simplifying restrictions that show general relativity as the base of the more general theory.

Deciphering the details of RNA aminoglycoside interactions: from atomistic models to biotechnological applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ilgu, Muslum

A detailed study was done of the neomycin-B RNA aptamer for determining its selectivity and binding ability to both neomycin– and kanamycin-class aminoglycosides. A novel method to increase drug concentrations in cells for more efficiently killing is described. To test the method, a bacterial model system was adopted and several small RNA molecules interacting with aminoglycosides were cloned downstream of T7 RNA polymerase promoter in an expression vector. Then, the growth analysis of E. coli expressing aptamers was observed for 12-hour period. Our analysis indicated that aptamers helped to increase the intracellular concentration of aminoglycosides thereby increasing their efficacy.

Rational design of gene-based vaccines.

PubMed

Barouch, Dan H

2006-01-01

Vaccine development has traditionally been an empirical discipline. Classical vaccine strategies include the development of attenuated organisms, whole killed organisms, and protein subunits, followed by empirical optimization and iterative improvements. While these strategies have been remarkably successful for a wide variety of viruses and bacteria, these approaches have proven more limited for pathogens that require cellular immune responses for their control. In this review, current strategies to develop and optimize gene-based vaccines are described, with an emphasis on novel approaches to improve plasmid DNA vaccines and recombinant adenovirus vector-based vaccines. Copyright 2006 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Gödel metrics with chronology protection in Horndeski gravities

NASA Astrophysics Data System (ADS)

Geng, Wei-Jian; Li, Shou-Long; Lü, H.; Wei, Hao

2018-05-01

Gödel universe, one of the most interesting exact solutions predicted by General Relativity, describes a homogeneous rotating universe containing naked closed time-like curves (CTCs). It was shown that such CTCs are the consequence of the null energy condition in General Relativity. In this paper, we show that the Gödel-type metrics with chronology protection can emerge in Einstein-Horndeski gravity. We construct such exact solutions also in Einstein-Horndeski-Maxwell and Einstein-Horndeski-Proca theories.

Closed Timelike Curves in (2+1)-AdS Gravity

NASA Astrophysics Data System (ADS)

Valtancoli, P.

We build the (2+1)-AdS gravity generalization of the Gott time machine using a first-order formalism for solving the scattering of point sources. The two-body dynamics is solved by two invariant masses, whose difference is simply related to the total angular momentum of the system. We show how to build a time machine when at least one of the two invariant masses is no more real but acquires an imaginary part.

Cosmological singularity theorems and splitting theorems for N-Bakry-Émery spacetimes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woolgar, Eric, E-mail: ewoolgar@ualberta.ca; Wylie, William, E-mail: wwylie@syr.edu

We study Lorentzian manifolds with a weight function such that the N-Bakry-Émery tensor is bounded below. Such spacetimes arise in the physics of scalar-tensor gravitation theories, including Brans-Dicke theory, theories with Kaluza-Klein dimensional reduction, and low-energy approximations to string theory. In the “pure Bakry-Émery” N = ∞ case with f uniformly bounded above and initial data suitably bounded, cosmological-type singularity theorems are known, as are splitting theorems which determine the geometry of timelike geodesically complete spacetimes for which the bound on the initial data is borderline violated. We extend these results in a number of ways. We are able tomore » extend the singularity theorems to finite N-values N ∈ (n, ∞) and N ∈ (−∞, 1]. In the N ∈ (n, ∞) case, no bound on f is required, while for N ∈ (−∞, 1] and N = ∞, we are able to replace the boundedness of f by a weaker condition on the integral of f along future-inextendible timelike geodesics. The splitting theorems extend similarly, but when N = 1, the splitting is only that of a warped product for all cases considered. A similar limited loss of rigidity has been observed in a prior work on the N-Bakry-Émery curvature in Riemannian signature when N = 1 and appears to be a general feature.« less

Unwrapping Closed Timelike Curves

NASA Astrophysics Data System (ADS)

Slobodov, Sergei

2008-12-01

Closed timelike curves (CTCs) appear in many solutions of the Einstein equation, even with reasonable matter sources. These solutions appear to violate causality and so are considered problematic. Since CTCs reflect the global properties of a spacetime, one can attempt to extend a local CTC-free patch of such a spacetime in a way that does not give rise to CTCs. One such procedure is informally known as unwrapping. However, changes in global identifications tend to lead to local effects, and unwrapping is no exception, as it introduces a special kind of singularity, called quasi-regular. This “unwrapping” singularity is similar to the string singularities. We define an unwrapping of a (locally) axisymmetric spacetime as the universal cover of the spacetime after one or more of the local axes of symmetry is removed. We give two examples of unwrapping of essentially 2+1 dimensional spacetimes with CTCs, the Gott spacetime and the Gödel spacetime. We show that the unwrapped Gott spacetime, while singular, is at least devoid of CTCs. In contrast, the unwrapped Gödel spacetime still contains CTCs through every point. A “multiple unwrapping” procedure is devised to remove the remaining circular CTCs. We conclude that, based on the given examples, CTCs appearing in the solutions of the Einstein equation are not simply a mathematical artifact of coordinate identifications. Alternative extensions of spacetimes with CTCs tend to lead to other pathologies, such as naked quasi-regular singularities.

Cosmological singularity theorems and splitting theorems for N-Bakry-Émery spacetimes

NASA Astrophysics Data System (ADS)

Woolgar, Eric; Wylie, William

2016-02-01

We study Lorentzian manifolds with a weight function such that the N-Bakry-Émery tensor is bounded below. Such spacetimes arise in the physics of scalar-tensor gravitation theories, including Brans-Dicke theory, theories with Kaluza-Klein dimensional reduction, and low-energy approximations to string theory. In the "pure Bakry-Émery" N = ∞ case with f uniformly bounded above and initial data suitably bounded, cosmological-type singularity theorems are known, as are splitting theorems which determine the geometry of timelike geodesically complete spacetimes for which the bound on the initial data is borderline violated. We extend these results in a number of ways. We are able to extend the singularity theorems to finite N-values N ∈ (n, ∞) and N ∈ (-∞, 1]. In the N ∈ (n, ∞) case, no bound on f is required, while for N ∈ (-∞, 1] and N = ∞, we are able to replace the boundedness of f by a weaker condition on the integral of f along future-inextendible timelike geodesics. The splitting theorems extend similarly, but when N = 1, the splitting is only that of a warped product for all cases considered. A similar limited loss of rigidity has been observed in a prior work on the N-Bakry-Émery curvature in Riemannian signature when N = 1 and appears to be a general feature.

Tyrosine Detoxification Is an Essential Trait in the Life History of Blood-Feeding Arthropods.

PubMed

Sterkel, Marcos; Perdomo, Hugo D; Guizzo, Melina G; Barletta, Ana Beatriz F; Nunes, Rodrigo D; Dias, Felipe A; Sorgine, Marcos H F; Oliveira, Pedro L

2016-08-22

Blood-feeding arthropods are vectors of infectious diseases such as dengue, Zika, Chagas disease, and malaria [1], and vector control is essential to limiting disease spread. Because these arthropods ingest very large amounts of blood, a protein-rich meal, huge amounts of amino acids are produced during digestion. Previous work on Rhodnius prolixus, a vector of Chagas disease, showed that, among all amino acids, only tyrosine degradation enzymes were overexpressed in the midgut compared to other tissues [2]. Here we demonstrate that tyrosine detoxification is an essential trait in the life history of blood-sucking arthropods. We found that silencing Rhodnius tyrosine aminotransferase (TAT) and 4-hydroxyphenylpyruvate dioxygenase (HPPD), the first two enzymes of the phenylalanine/tyrosine degradation pathway, caused the death of insects after a blood meal. This was confirmed by using the HPPD inhibitor mesotrione, which selectively killed hematophagous arthropods but did not affect non-hematophagous insects. In addition, mosquitoes and kissing bugs died after feeding on mice that had previously received a therapeutic effective oral dose (1 mg/kg) of nitisinone, another HPPD inhibitor used in humans for the treatment of tyrosinemia type I [3]. These findings indicate that HPPD (and TAT) can be a target for the selective control of blood-sucking disease vector populations. Because HPPD inhibitors are extensively used as herbicides and in medicine, these compounds may provide an alternative less toxic to humans and more environmentally friendly than the conventional neurotoxic insecticides that are currently used, with the ability to affect only hematophagous arthropods. Copyright © 2016 Elsevier Ltd. All rights reserved.

An alternative approach in regulation of expression of a transgene by endogenous miR-145 in carcinoma and normal breast cell lines.

PubMed

Ghanbari Safari, Maryam; Baesi, Kazem; Hosseinkhani, Saman

2017-03-01

MicroRNAs are small noncoding RNAs that regulate gene expression by repressing translation of target cellular transcripts. Increasing evidences indicate that miRNAs have different expression profiles and play crucial roles in numerous cellular processes. Delivery and expression of transgenes for cancer therapy must be specific for tumors to avoid killing of healthy tissues. Many investigators have shown that transgene expression can be suppressed in normal cells using vectors that are responsive to microRNA regulation. To overcome this problem, miR-145 that exhibits downregulation in many types of cancer cells was chosen for posttranscriptional regulatory systems mediated by microRNAs. In this study, a psiCHECK-145T vector carrying four tandem copies of target sequences of miR-145 into 3'-UTR of the Renilla luciferase gene was constructed. Renilla luciferase activity from the psiCHECK-145T vector was 57% lower in MCF10A cells with high miR-145 expression as compared to a control condition. Additionally, overexpression of miR-145 in MCF-7 cells with low expression level of miR-145 showed more than 76% reduction in the Renilla luciferase activity from the psiCHECK-145T vector. Inclusion of miR-145 target sequences into the 3'-UTR of the Renilla luciferase gene is a feasible strategy for restricting transgene expression in a breast cancer cell line while sparing a breast normal cell line. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

Anopheles Midgut Epithelium Evades Human Complement Activity by Capturing Factor H from the Blood Meal

PubMed Central

Khattab, Ayman; Barroso, Marta; Miettinen, Tiera; Meri, Seppo

2015-01-01

Hematophagous vectors strictly require ingesting blood from their hosts to complete their life cycles. Exposure of the alimentary canal of these vectors to the host immune effectors necessitates efficient counteractive measures by hematophagous vectors. The Anopheles mosquito transmitting the malaria parasite is an example of hematophagous vectors that within seconds can ingest human blood double its weight. The innate immune defense mechanisms, like the complement system, in the human blood should thereby immediately react against foreign cells in the mosquito midgut. A prerequisite for complement activation is that the target cells lack complement regulators on their surfaces. In this work, we analyzed whether human complement is active in the mosquito midgut, and how the mosquito midgut cells protect themselves against complement attack. We found that complement remained active for a considerable time and was able to kill microbes within the mosquito midgut. However, the Anopheles mosquito midgut cells were not injured. These cells were found to protect themselves by capturing factor H, the main soluble inhibitor of the alternative complement pathway. Factor H inhibited complement on the midgut cells by promoting inactivation of C3b to iC3b and preventing the activity of the alternative pathway amplification C3 convertase enzyme. An interference of the FH regulatory activity by monoclonal antibodies, carried to the midgut via blood, resulted in increased mosquito mortality and reduced fecundity. By using a ligand blotting assay, a putative mosquito midgut FH receptor could be detected. Thereby, we have identified a novel mechanism whereby mosquitoes can tolerate human blood. PMID:25679788

Lethal and Pre-Lethal Effects of a Fungal Biopesticide Contribute to Substantial and Rapid Control of Malaria Vectors

PubMed Central

Blanford, Simon; Shi, Wangpeng; Christian, Riann; Marden, James H.; Koekemoer, Lizette L.; Brooke, Basil D.; Coetzee, Maureen; Read, Andrew F.; Thomas, Matthew B.

2011-01-01

Rapidly emerging insecticide resistance is creating an urgent need for new active ingredients to control the adult mosquitoes that vector malaria. Biopesticides based on the spores of entomopathogenic fungi have shown considerable promise by causing very substantial mortality within 7–14 days of exposure. This mortality will generate excellent malaria control if there is a high likelihood that mosquitoes contact fungi early in their adult lives. However, where contact rates are lower, as might result from poor pesticide coverage, some mosquitoes will contact fungi one or more feeding cycles after they acquire malaria, and so risk transmitting malaria before the fungus kills them. Critics have argued that ‘slow acting’ fungal biopesticides are, therefore, incapable of delivering malaria control in real-world contexts. Here, utilizing standard WHO laboratory protocols, we demonstrate effective action of a biopesticide much faster than previously reported. Specifically, we show that transient exposure to clay tiles sprayed with a candidate biopesticide comprising spores of a natural isolate of Beauveria bassiana, could reduce malaria transmission potential to zero within a feeding cycle. The effect resulted from a combination of high mortality and rapid fungal-induced reduction in feeding and flight capacity. Additionally, multiple insecticide-resistant lines from three key African malaria vector species were completely susceptible to fungus. Thus, fungal biopesticides can block transmission on a par with chemical insecticides, and can achieve this where chemical insecticides have little impact. These results support broadening the current vector control paradigm beyond fast-acting chemical toxins. PMID:21897846

Causal Structure around Spinning 5-DIMENSIONAL Cosmic Strings

NASA Astrophysics Data System (ADS)

Slagter, Reinoud Jan

2008-09-01

We present a numerical solution of a stationary 5-dimensional spinning cosmic string in the Einstein-Yang-Mills (EYM) model, where the extra bulk coordinate ψ is periodic. It turns out that when gψψ approaches zero, i.e., a closed time-like curve (CTC) would appear, the solution becomes singular. We also investigated the geometrical structure of the static 5D cosmic string. Two opposite moving 5D strings could, in contrast with the 4D case, fulfil the Gott condition for CTC formation.

Rotating Black Holes and the Kerr Metric

NASA Astrophysics Data System (ADS)

Kerr, Roy Patrick

2008-10-01

Since it was first discovered in 1963 the Kerr metric has been used by relativists as a test-bed for conjectures on worm-holes, time travel, closed time-like loops, and the existence or otherwise of global Cauchy surfaces. More importantly, it has also used by astrophysicists to investigate the effects of collapsed objects on their local environments. These two groups of applications should not be confused. Astrophysical Black Holes are not the same as the Kruskal solution and its generalisations.

Triple collinear emissions in parton showers

DOE PAGES

Hoche, Stefan; Prestel, Stefan

2017-10-17

A framework to include triple collinear splitting functions into parton showers is presented, and the implementation of flavor-changing next-to-leading-order (NLO) splitting kernels is discussed as a first application. The correspondence between the Monte Carlo integration and the analytic computation of NLO DGLAP evolution kernels is made explicit for both timelike and spacelike parton evolution. Finally, numerical simulation results are obtained with two independent implementations of the new algorithm, using the two independent event generation frameworks PYTHIA and SHERPA.

Differential immune responses of Monochamus alternatus against symbiotic and entomopathogenic fungi.

PubMed

Zhang, Wei; Meng, Jie; Ning, Jing; Qin, Peijun; Zhou, Jiao; Zou, Zhen; Wang, Yanhong; Jiang, Hong; Ahmad, Faheem; Zhao, Lilin; Sun, Jianghua

2017-08-01

Monochamus alternatus, the main vector beetles of invasive pinewood nematode, has established a symbiotic relationship with a native ectotrophic fungal symbiont, Sporothrix sp. 1, in China. The immune response of M. alternatus to S. sp. 1 in the coexistence of beetles and fungi is, however, unknown. Here, we report that immune responses of M. alternatus pupae to infection caused by ectotrophic symbiotic fungus S. sp. 1 and entomopathogenic fungus Beauveria bassiana differ significantly. The S. sp. 1 did not kill the beetles while B. bassiana killed all upon injection. The transcriptome results showed that the numbers of differentially expressed genes in M. alternatus infected with S. sp. 1 were 2-fold less than those infected with B. bassiana at 48 hours post infection. It was noticed that Toll and IMD pathways played a leading role in the beetle's immune system when infected by symbiotic fungus, but upon infection by entomopathogenic fungus, only the Toll pathway gets triggered actively. Furthermore, the beetles could tolerate the infection of symbiotic fungi by retracing their Toll and IMD pathways at 48 h. This study provided a comprehensive sequence resource of M. alternatus transcriptome for further study of the immune interactions between host and associated fungi.

Inactivated- or killed-virus HIV/AIDS vaccines.

PubMed

Sheppard, Haynes W

2005-06-01

Inactivated or "killed" virus (KV) is a "classical" approach that has produced safe and effective human and veterinary vaccines but has received relatively little attention in the effort to develop an HIV/AIDS vaccine. Initially, KV and rgp120 subunit vaccines were the two most obvious approaches but, unfortunately, rgp120 has not been efficacious and the KV approach has been limited by a variety of scientific, technical, and sociological factors. For example, when responses to cellular antigens, present on SIV grown in human cells, proved to be largely responsible for efficacy, the KV approach was widely discounted. Similarly, when lab-adapted HIV-1 appeared to lose envelope glycoprotein during preparation (not the case for primary isolates), this was viewed as a fundamental barrier to the KV concept. Also, a preference for "safer", genetically-engineered vaccines, and emphasis on cellular immunity, have left KV low on the priority list for funding agencies and investigators. The recent suggestion that "native" trimeric gp120 displays conserved conformational neutralization epitopes, along with the failure of rgp120, and difficulties in raising strong cellular responses with DNA or vectored vaccines, has restored some interest in the KV concept. In the past 15 years, several groups have initiated pre-clinical development of KV candidates for SIV or HIV and promising, albeit limited, information has been produced. In this chapter we discuss the rationale (including pros and cons) for producing and testing killed-HIV vaccines, the prospects for success, the nature and scope of research needed to test the KV concept, what has been learned to date, and what remains undone.

Electroporation driven delivery of both an IL-12 expressing plasmid and cisplatin synergizes to inhibit B16 melanoma tumor growth through an NK cell mediated tumor killing mechanism.

PubMed

Kim, Ha; Sin, Jeong-Im

2012-11-01

Combined therapy using chemotherapeutic drugs and immunotherapeutics offers some promise for treating patients with cancer. In this study, we evaluated whether cisplatin delivered by intratumoral (IT)-electroporation (EP) might enhance antitumor activity against established B16 melanoma and whether further addition of intramuscular (IM)-EP of IL-12 cDNA to IT-EP of cisplatin might augment antitumor therapeutic activity, with a focus on the underlining antitumor mechanism(s). When tumor (7 mm)-bearing animals were treated locally with cisplatin by IT-EP, they showed tumor growth inhibition significantly more than those without IT-EP. Moreover, IL-12 cDNA delivered by IM-EP was also able to inhibit tumor growth significantly more than control vector delivery. This tumor growth inhibition was mediated by NK cells, but not CD4+ T or CD8+ T cells, as determined by immune cell subset depletion and IFN-γ induction. Moreover, concurrent therapy using IT-EP of cisplatin plus IM-EP of IL-12 cDNA displayed antitumor therapeutic synergy. This therapeutic synergy appeared to be mediated by increased sensitivity of cisplatin-treated tumors to NK cell-mediated tumor killing. Taken together, these data support that cisplatin delivery by IT-EP plus IL-12 gene delivery by IM-EP are more effective at inducing antitumor therapeutic responses through increased sensitivity of cisplatin-treated tumors to NK cell-mediated tumor killing. This combined approach might have some implication for treating melanoma in patients.

Occurrence of pathogenic fungi to Amblyomma cajennense in a rural area of Central Brazil and their activities against vectors of Rocky Mountain spotted fever.

PubMed

D'Alessandro, Walmirton B; Humber, Richard A; Luz, Christian

2012-08-13

Two isolates of Beauveria bassiana and one of Purpureocillium lilacinum (=Paecilomyces lilacinus) were found infecting Amblyomma cajennense engorged females collected on horses (0.15% infection rate from a total of 1982 specimens) and another two isolates of P. lilacinum and one Metarhizium anisopliae detected in soils (2.1% from 144 samples) collected in typical pasture habitats of this tick in Central Brazil from October 2009 to March 2011. Fungi were isolated from soils with Rhipicephalus sanguineus as surrogate baits. No fungi were found in ticks or soils during the driest months (May to August). Testing pathogenicity of fungi all R. sanguineus females were killed regardless of the isolate and fungi sporulated abundantly on the cadavers. A. cajennense was less susceptible to infection with P. lilacinum within 20 days than R. sanguineus. All three fungal species probably act as natural antagonists of A. cajennense particularly in the rainy season and have interest for integrate control of vectors of Rocky Mountain spotted fever. Copyright © 2012 Elsevier B.V. All rights reserved.

Experimental Vaccines against Chagas Disease: A Journey through History.

PubMed

Rodríguez-Morales, Olivia; Monteón-Padilla, Víctor; Carrillo-Sánchez, Silvia C; Rios-Castro, Martha; Martínez-Cruz, Mariana; Carabarin-Lima, Alejandro; Arce-Fonseca, Minerva

2015-01-01

Chagas disease, or American trypanosomiasis, which is caused by the protozoan parasite Trypanosoma cruzi, is primarily a vector disease endemic in 21 Latin American countries, including Mexico. Although many vector control programs have been implemented, T. cruzi has not been eradicated. The development of an anti-T. cruzi vaccine for prophylactic and therapeutic purposes may significantly contribute to the transmission control of Chagas disease. Immune protection against experimental infection with T. cruzi has been studied since the second decade of the last century, and many types of immunogens have been used subsequently, such as killed or attenuated parasites and new DNA vaccines. This primary prevention strategy appears feasible, effective, safe, and inexpensive, although problems remain. The objective of this review is to summarize the research efforts about the development of vaccines against Chagas disease worldwide. A thorough literature review was conducted by searching PubMed with the terms "Chagas disease" and "American trypanosomiasis" together with "vaccines" or "immunization". In addition, reports and journals not cited in PubMed were identified. Publications in English, Spanish, and Portuguese were reviewed.

Repellent, irritant and toxic effects of 20 plant extracts on adults of the malaria vector Anopheles gambiae mosquito.

PubMed

Deletre, Emilie; Martin, Thibaud; Campagne, Pascal; Bourguet, Denis; Cadin, Andy; Menut, Chantal; Bonafos, Romain; Chandre, Fabrice

2013-01-01

Pyrethroid insecticides induce an excito-repellent effect that reduces contact between humans and mosquitoes. Insecticide use is expected to lower the risk of pathogen transmission, particularly when impregnated on long-lasting treated bednets. When applied at low doses, pyrethroids have a toxic effect, however the development of pyrethroid resistance in several mosquito species may jeopardize these beneficial effects. The need to find additional compounds, either to kill disease-carrying mosquitoes or to prevent mosquito contact with humans, therefore arises. In laboratory conditions, the effects (i.e., repellent, irritant and toxic) of 20 plant extracts, mainly essential oils, were assessed on adults of Anopheles gambiae, a primary vector of malaria. Their effects were compared to those of DEET and permethrin, used as positive controls. Most plant extracts had irritant, repellent and/or toxic effects on An. gambiae adults. The most promising extracts, i.e. those combining the three types of effects, were from Cymbopogon winterianus, Cinnamomum zeylanicum and Thymus vulgaris. The irritant, repellent and toxic effects occurred apparently independently of each other, and the behavioural response of adult An. gambiae was significantly influenced by the concentration of the plant extracts. Mechanisms underlying repellency might, therefore, differ from those underlying irritancy and toxicity. The utility of the efficient plant extracts for vector control as an alternative to pyrethroids may thus be envisaged.

Improved vectors for transcriptional/translational signal screening in corynebacteria using the melC operon from Streptomyces glaucescens as reporter.

PubMed

Adham, Sirin A I; Rodríguez, Sonia; Ramos, Angelina; Santamaría, Ramón I; Gil, José A

2003-07-01

The tyrosinase operon ( melC) from Streptomyces glaucescens was cloned and functionally expressed in Brevibacterium lactofermentum and Corynebacterium glutamicum under the control of the promoter of the kan gene from Tn 5. Recombinant corynebacterial cells containing the tyrosinase operon produced melanin on agar plates and in liquid culture when supplemented with copper and tyrosine. A conjugative bifunctional replacement vector for transcriptional/translational signal screening (pEMel-1) was constructed using expression of the melC operon from S. glaucescens, which can be used for cloning promoter sequences as EcoRI- NdeI fragments. When the DNA fragments with promoter activity such as cspBp or trpp were inserted into pEMel-1, B. lactofermentum harboring the chimeric plasmids produced melanin at different stages of growth, allowing temporal detection of promoter activity. The vector was also used to detect the activity of a Streptomyces promoter ( xysAp), which was inactive in B. lactofermentum, after PCR mutagenesis. The melC operon can be used for the visual, inexpensive (compared to the high price of starch azure for amylase detection), and non-selective (in contrast to the kan or cat genes) screening of several thousand clones at high colony density without killing of the transformants due to the presence of iodine (as in the case of amylase assay).

Repellent, Irritant and Toxic Effects of 20 Plant Extracts on Adults of the Malaria Vector Anopheles gambiae Mosquito

PubMed Central

Deletre, Emilie; Martin, Thibaud; Campagne, Pascal; Bourguet, Denis; Cadin, Andy; Menut, Chantal; Bonafos, Romain; Chandre, Fabrice

2013-01-01

Pyrethroid insecticides induce an excito-repellent effect that reduces contact between humans and mosquitoes. Insecticide use is expected to lower the risk of pathogen transmission, particularly when impregnated on long-lasting treated bednets. When applied at low doses, pyrethroids have a toxic effect, however the development of pyrethroid resistance in several mosquito species may jeopardize these beneficial effects. The need to find additional compounds, either to kill disease-carrying mosquitoes or to prevent mosquito contact with humans, therefore arises. In laboratory conditions, the effects (i.e., repellent, irritant and toxic) of 20 plant extracts, mainly essential oils, were assessed on adults of Anopheles gambiae, a primary vector of malaria. Their effects were compared to those of DEET and permethrin, used as positive controls. Most plant extracts had irritant, repellent and/or toxic effects on An. gambiae adults. The most promising extracts, i.e. those combining the three types of effects, were from Cymbopogon winterianus, Cinnamomum zeylanicum and Thymus vulgaris. The irritant, repellent and toxic effects occurred apparently independently of each other, and the behavioural response of adult An. gambiae was significantly influenced by the concentration of the plant extracts. Mechanisms underlying repellency might, therefore, differ from those underlying irritancy and toxicity. The utility of the efficient plant extracts for vector control as an alternative to pyrethroids may thus be envisaged. PMID:24376515

Targeting cattle for malaria elimination: marked reduction of Anopheles arabiensis survival for over six months using a slow-release ivermectin implant formulation.

PubMed

Chaccour, Carlos J; Ngha'bi, Kija; Abizanda, Gloria; Irigoyen Barrio, Angel; Aldaz, Azucena; Okumu, Fredros; Slater, Hannah; Del Pozo, Jose Luis; Killeen, Gerry

2018-05-04

Mosquitoes that feed on animals can survive and mediate residual transmission of malaria even after most humans have been protected with insecticidal bednets or indoor residual sprays. Ivermectin is a widely-used drug for treating parasites of humans and animals that is also insecticidal, killing mosquitoes that feed on treated subjects. Mass administration of ivermectin to livestock could be particularly useful for tackling residual malaria transmission by zoophagic vectors that evade human-centred approaches. Ivermectin comes from a different chemical class to active ingredients currently used to treat bednets or spray houses, so it also has potential for mitigating against emergence of insecticide resistance. However, the duration of insecticidal activity obtained with ivermectin is critical to its effectiveness and affordability. A slow-release formulation for ivermectin was implanted into cattle, causing 40 weeks of increased mortality among Anopheles arabiensis that fed on them. For this zoophagic vector of residual malaria transmission across much of Africa, the proportion surviving three days after feeding (typical mean duration of a gonotrophic cycle in field populations) was approximately halved for 25 weeks. This implantable ivermectin formulation delivers stable and sustained insecticidal activity for approximately 6 months. Residual malaria transmission by zoophagic vectors could be suppressed by targeting livestock with this long-lasting formulation, which would be impractical or unacceptable for mass treatment of human populations.

Wash-resistance of pirimiphos-methyl insecticide treatments of window screens and eave baffles for killing indoor-feeding malaria vector mosquitoes: an experimental hut trial, South East of Zambia.

PubMed

Chinula, Dingani; Sikaala, Chadwick H; Chanda-Kapata, Pascalina; Hamainza, Busiku; Zulu, Reuben; Reimer, Lisa; Chizema, Elizabeth; Kiware, Samson; Okumu, Fredros O; Killeen, Gerry

2018-04-13

The effectiveness of long-lasting insecticidal-treated nets (LLINs) and indoor residual spraying (IRS) for malaria control is threatened by resistance to commonly used pyrethroid insecticides. Rotations, mosaics, combinations, or mixtures of insecticides from different complementary classes are recommended by the World Health Organization (WHO) for mitigating against resistance, but many of the alternatives to pyrethroids are prohibitively expensive to apply in large national IRS campaigns. Recent evaluations of window screens and eave baffles (WSEBs) treated with pirimiphos-methyl (PM), to selectively target insecticides inside houses, demonstrated malaria vector mortality rates equivalent or superior to IRS. However, the durability of efficacy when co-applied with polyacrylate-binding agents (BA) remains to be established. This study evaluated whether WSEBs, co-treated with PM and BA have comparable wash resistance to LLINs and might therefore remain insecticidal for years rather than months. WHO-recommended wire ball assays of insecticidal efficacy were applied to polyester netting treated with or without BA plus 1 or 2 g/sq m PM. They were then tested for insecticidal efficacy using fully susceptible insectary-reared Anopheles gambiae mosquitoes, following 0, 5, 10, 15, then 20 washes as per WHO-recommended protocols for accelerated ageing of LLINs. This was followed by a small-scale field trial in experimental huts to measure malaria vector mortality achieved by polyester netting WSEBs treated with BA and 2 g/sq m PM after 0, 10 and then 20 standardized washes, alongside recently applied IRS using PM. Co-treatment with BA and either dosage of PM remained insecticidal over 20 washes in the laboratory. In experimental huts, WSEBs treated with PM plus BA consistently killed similar proportions of Anopheles arabiensis mosquitoes to PM-IRS (both consistently ≥ 94%), even after 20 washes. Co-treating WSEBs with both PM and BA results in wash-resistant insecticidal activity comparable with LLINs. Insecticide treatments for WSEBs may potentially last for years rather than months, therefore, reducing insecticide consumption by an order of magnitude relative to IRS. However, durability of WSEBs will still have to be assessed in real houses under representative field conditions of exposure to wear and tear, sunlight and rain.

Field trial on a novel control method for the dengue vector, Aedes aegypti by the systematic use of Olyset® Net and pyriproxyfen in Southern Vietnam

PubMed Central

2013-01-01

Background Jars, tanks, and drums provide favorable rearing/breeding sites for Aedes aegypti in Vietnam. However, the use of insecticides to control mosquitoes at such breeding sites has not been approved in Vietnam since they are also often sources of drinking water, making larval vector control difficult. Mosquito nets pre-treated with long-lasting insecticide treated nets (LLITNs) form an effective measure for malaria control. We examined changes in the abundance of immature Aedes aegypti to evaluate the efficacy of covering ceramic jars with lids comprising one type of LLITN, Olyset® Net, in inhibiting oviposition by adult females, and to evaluate the effect of treating other breeding containers, such as flower vases, inside and around the outside of houses with a slow-release pyriproxyfen formulation to kill pupae. Methods We selected 313 households for the trial and 363 households for the control in Tan Chanh, Long An province, Vietnam. In the trial area, Olyset® Net lids were used to cover five major types of water container (ceramic jars, cylindrical concrete tanks, other concrete tanks, plastic drums, and plastic buckets), while pyriproxyfen was used to treat flower vases and ant traps. We also monitored dengue virus transmission by measuring anti-dengue IgM and IgG levels in healthy residents in both control and trial areas to estimate the effectiveness of Olyset® Net at controlling the dengue vector, Aedes aegypti. Results The container-index and house-index for immature Ae. aegypti fell steeply one month after treatment in the trial area. Lids with Olyset® Net that fit container openings clearly seemed to reduce the presence of immature Ae. aegypti as the density of pupae decreased 1 month after treatment in the trial area. Pyriproxyfen was also effective at killing pupae in the water containers in the trial area. Although the dengue seroconversion rate was not influenced by Olyset® Net, it was lower in two-five year old children when compared to older children and adults in both control and trial areas. Conclusions Our study showed that the treatment by Olyset® Net and pyriproxyfen had a strong negative effect on the prevalence of immature Ae. aegypti, which persisted for at least 5 months after treatment. PMID:23312018

Field trial on a novel control method for the dengue vector, Aedes aegypti by the systematic use of Olyset® Net and pyriproxyfen in Southern Vietnam.

PubMed

Tsunoda, Takashi; Kawada, Hitoshi; Huynh, Trang T T; Luu, Loan Le; Le, San Hoang; Tran, Huu Ngoc; Vu, Huong Thi Que; Le, Hieu Minh; Hasebe, Futoshi; Tsuzuki, Ataru; Takagi, Masahiro

2013-01-11

Jars, tanks, and drums provide favorable rearing/breeding sites for Aedes aegypti in Vietnam. However, the use of insecticides to control mosquitoes at such breeding sites has not been approved in Vietnam since they are also often sources of drinking water, making larval vector control difficult. Mosquito nets pre-treated with long-lasting insecticide treated nets (LLITNs) form an effective measure for malaria control. We examined changes in the abundance of immature Aedes aegypti to evaluate the efficacy of covering ceramic jars with lids comprising one type of LLITN, Olyset® Net, in inhibiting oviposition by adult females, and to evaluate the effect of treating other breeding containers, such as flower vases, inside and around the outside of houses with a slow-release pyriproxyfen formulation to kill pupae. We selected 313 households for the trial and 363 households for the control in Tan Chanh, Long An province, Vietnam. In the trial area, Olyset® Net lids were used to cover five major types of water container (ceramic jars, cylindrical concrete tanks, other concrete tanks, plastic drums, and plastic buckets), while pyriproxyfen was used to treat flower vases and ant traps. We also monitored dengue virus transmission by measuring anti-dengue IgM and IgG levels in healthy residents in both control and trial areas to estimate the effectiveness of Olyset® Net at controlling the dengue vector, Aedes aegypti. The container-index and house-index for immature Ae. aegypti fell steeply one month after treatment in the trial area. Lids with Olyset® Net that fit container openings clearly seemed to reduce the presence of immature Ae. aegypti as the density of pupae decreased 1 month after treatment in the trial area. Pyriproxyfen was also effective at killing pupae in the water containers in the trial area. Although the dengue seroconversion rate was not influenced by Olyset® Net, it was lower in two-five year old children when compared to older children and adults in both control and trial areas. Our study showed that the treatment by Olyset® Net and pyriproxyfen had a strong negative effect on the prevalence of immature Ae. aegypti, which persisted for at least 5 months after treatment.

Classification of the Lie and Noether point symmetries for the Wave and the Klein-Gordon equations in pp-wave spacetimes

NASA Astrophysics Data System (ADS)

Paliathanasis, A.; Tsamparlis, M.; Mustafa, M. T.

2018-02-01

A complete classification of the Lie and Noether point symmetries for the Klein-Gordon and the wave equation in pp-wave spacetimes is obtained. The classification analysis is carried out by reducing the problem of the determination of the point symmetries to the problem of existence of conformal killing vectors on the pp-wave spacetimes. Employing the existing results for the isometry classes of the pp-wave spacetimes, the functional form of the potential is determined for which the Klein-Gordon equation admits point symmetries and Noetherian conservation law. Finally the Lie and Noether point symmetries of the wave equation are derived.

Spacetime symmetries and topology in bimetric relativity

NASA Astrophysics Data System (ADS)

Torsello, Francesco; Kocic, Mikica; Högâs, Marcus; Mörtsell, Edvard

2018-04-01

We explore spacetime symmetries and topologies of the two metric sectors in Hassan-Rosen bimetric theory. We show that, in vacuum, the two sectors can either share or have separate spacetime symmetries. If stress-energy tensors are present, a third case can arise, with different spacetime symmetries within the same sector. This raises the question of the best definition of spacetime symmetry in Hassan-Rosen bimetric theory. We emphasize the possibility of imposing ansatzes and looking for solutions having different Killing vector fields or different isometries in the two sectors, which has gained little attention so far. We also point out that the topology of spacetime imposes a constraint on possible metric combinations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baguet, A.; Pope, Christopher N.; Samtleben, H.

We prove an old conjecture by Duff, Nilsson, Pope and Warner asserting that the NSNS sector of supergravity (and more general the bosonic string) allows for a consistent Pauli reduction on any d-dimensional group manifold G, keeping the full set of gauge bosons of the G×G isometry group of the bi-invariant metric on G. The main tool of the construction is a particular generalised Scherk–Schwarz reduction ansatz in double field theory which we explicitly construct in terms of the group's Killing vectors. Examples include the consistent reduction from ten dimensions on S3×S3 and on similar product spaces. The construction ismore » another example of globally geometric non-toroidal compactifications inducing non-geometric fluxes.« less

Smuggling across the border: how arthropod-borne pathogens evade and exploit the host defense system of the skin.

PubMed

Bernard, Quentin; Jaulhac, Benoit; Boulanger, Nathalie

2014-05-01

The skin is a critical barrier between hosts and pathogens in arthropod-borne diseases. It harbors many resident cells and specific immune cells to arrest or limit infections by secreting inflammatory molecules or by directly killing pathogens. However, some pathogens are able to use specific skin cells and arthropod saliva for their initial development, to hide from the host immune system, and to establish persistent infection in the vertebrate host. A better understanding of the initial mechanisms taking place in the skin should allow the development of new strategies to fight these vector-borne pathogens that are spread worldwide and are of major medical importance.

Quantum Physics, Fields and Closed Timelike Curves: The D-CTC Condition in Quantum Field Theory

NASA Astrophysics Data System (ADS)

Tolksdorf, Jürgen; Verch, Rainer

2018-01-01

The D-CTC condition has originally been proposed by David Deutsch as a condition on states of a quantum communication network that contains "backward time-steps" in some of its branches. It has been argued that this is an analogue for quantum processes in the presence of closed timelike curves (CTCs). The unusual properties of states of quantum communication networks that fulfill the D-CTC condition have been discussed extensively in recent literature. In this work, the D-CTC condition is investigated in the framework of quantum field theory in the local, operator-algebraic approach due to Haag and Kastler. It is shown that the D-CTC condition cannot be fulfilled in states that are analytic in the energy, or satisfy the Reeh-Schlieder property, for a certain class of processes and initial conditions. On the other hand, if a quantum field theory admits sufficiently many uncorrelated states across acausally related spacetime regions (as implied by the split property), then the D-CTC condition can always be fulfilled approximately to arbitrary precision. As this result pertains to quantum field theory on globally hyperbolic spacetimes where CTCs are absent, one may conclude that interpreting the D-CTC condition as characteristic for quantum processes in the presence of CTCs could be misleading, and should be regarded with caution. Furthermore, a construction of the quantized massless Klein-Gordon field on the Politzer spacetime, often viewed as spacetime analogue for quantum communication networks with backward time-steps, is proposed in this work.

Holographic entanglement entropies for Schwarzschild and Reisner-Nordström black holes in asymptotically Minkowski spacetimes

NASA Astrophysics Data System (ADS)

Sun, Yuan; Zhao, Liu

2017-04-01

Holographic entanglement entropies (HEE) associated with four-dimensional Schwarzschild and Reisner-Nordström (RN) black holes in asymptotically Minkowski spacetimes are investigated. Unlike the cases of asymptotically AdS spacetimes for which the boundaries are always taken at (timelike) conformal infinities, we take the boundaries at either large but finite radial coordinates (far boundary) or very close to the black hole event horizons (near horizon boundary). The reason for such choices is that such boundaries are similar to the conformal infinity of AdS spacetime in that they are all timelike, so that there may be some hope to define dual systems with ordinary time evolution on such boundaries. Our results indicate that, in the case of far boundaries, the leading-order contribution to HEEs comes from the background Minkowski spacetime; however, the next-to-leading-order contribution which arises from the presence of the black holes is always proportional to the black hole mass, which constitutes a version of the first law of HEE for asymptotically flat spacetimes, and the higher-order contributions are always negligibly small. In the case of near horizon boundaries, the leading-order contribution to HEE is always proportional to the area of the black hole event horizon, and the case of extremal RN black holes is distinguished from the cases of nonextremal black holes in that the minimal surface defining HEE is completely immersed inside the boundary up to the second order in the perturbative expansion.

Complete conformal classification of the Friedmann–Lemaître–Robertson–Walker solutions with a linear equation of state

NASA Astrophysics Data System (ADS)

Harada, Tomohiro; Carr, B. J.; Igata, Takahisa

2018-05-01

We completely classify Friedmann–Lemaître–Robertson–Walker solutions with spatial curvature and equation of state , according to their conformal structure, singularities and trapping horizons. We do not assume any energy conditions and allow , thereby going beyond the usual well-known solutions. For each spatial curvature, there is an initial spacelike big-bang singularity for w  >  ‑1/3 and , while there is no big-bang singularity for w  <  ‑1 and . For K  =  0 or  ‑1, ‑1  <  w  <  ‑1/3 and , there is an initial null big-bang singularity. For each spatial curvature, there is a final spacelike future big-rip singularity for w  <  ‑1 and , with null geodesics being future complete for but incomplete for w  <  ‑5/3. For w  =  ‑1/3, the expansion speed is constant. For  ‑1  <  w  <  ‑1/3 and K  =  1, the universe contracts from infinity, then bounces and expands back to infinity. For K  =  0, the past boundary consists of timelike infinity and a regular null hypersurface for  ‑5/3  <  w  <  ‑1, while it consists of past timelike and past null infinities for . For w  <  ‑1 and K  =  1, the spacetime contracts from an initial spacelike past big-rip singularity, then bounces and blows up at a final spacelike future big-rip singularity. For w  <  ‑1 and K  =  ‑1, the past boundary consists of a regular null hypersurface. The trapping horizons are timelike, null and spacelike for , and , respectively. A negative energy density () is possible only for K  =  ‑1. In this case, for w  >  ‑1/3, the universe contracts from infinity, then bounces and expands to infinity; for  ‑1  <  w  <  ‑1/3, it starts from a big-bang singularity and contracts to a big-crunch singularity; for w  <  ‑1, it expands from a regular null hypersurface and contracts to another regular null hypersurface.

Combining indoor and outdoor methods for controlling malaria vectors: an ecological model of endectocide-treated livestock and insecticidal bed nets.

PubMed

Yakob, Laith; Cameron, Mary; Lines, Jo

2017-03-13

Malaria is spread by mosquitoes that are increasingly recognised to have diverse biting behaviours. How a mosquito in a specific environment responds to differing availability of blood-host species is largely unknown and yet critical to vector control efficacy. A parsimonious mathematical model is proposed that accounts for a diverse range of host-biting behaviours and assesses their impact on combining long-lasting insecticidal nets (LLINs) with a novel approach to malaria control: livestock treated with insecticidal compounds ('endectocides') that kill biting mosquitoes. Simulations of a malaria control programme showed marked differences across biting ecologies in the efficacy of both LLINs as a stand-alone tool and the combination of LLINs with endectocide-treated cattle. During the intervals between LLIN mass campaigns, concordant use of endectocides is projected to reduce the bounce-back in malaria prevalence that can occur as LLIN efficacy decays over time, especially if replacement campaigns are delayed. Integrating these approaches can also dramatically improve the attainability of local elimination; endectocidal treatment schedules required to achieve this aim are provided for malaria vectors with different biting ecologies. Targeting blood-feeding mosquitoes by treating livestock with endectocides offers a potentially useful complement to existing malaria control programmes centred on LLIN distribution. This approach is likely to be effective against vectors with a wide range of host-preferences and biting behaviours, with the exception of species that are so strictly anthropophilic that most blood meals are taken on humans even when humans are much less available than non-human hosts. Identifying this functional relationship in wild mosquito populations and ascertaining the extent to which it differs, within as well as between species, is a critical next step before targets can be set for employing this novel approach and combination.

Transduction of Nonhuman Primate Brain with Adeno-Associated Virus Serotype 1: Vector Trafficking and Immune Response

PubMed Central

Forsayeth, John; Mirek, Hanna; Munson, Keith; Bringas, John; Pivirotto, Phil; McBride, Jodi L; Davidson, Beverly L.; Bankiewicz, Krystof S.

2009-01-01

Abstract We used convection-enhanced delivery (CED) to characterize gene delivery mediated by adeno-associated virus type 1 (AAV1) by tracking expression of hrGFP (humanized green fluorescent protein from Renilla reniformis) into the striatum, basal forebrain, and corona radiata of monkey brain. Four cynomolgus monkeys received single infusions into corona radiata, putamen, and caudate. The other group (n = 4) received infusions into basal forebrain. Thirty days after infusion animals were killed and their brains were processed for immunohisto-chemical evaluation. Volumetric analysis of GFP-positive brain areas was performed. AAV1-hrGFP infusions resulted in approximately 550, 700, and 73 mm3 coverage after infusion into corona radiata, striatum, and basal forebrain, respectively. Aside from targeted regions, other brain structures also showed GFP signal (internal and external globus pallidus, subthalamic nucleus), supporting the idea that AAV1 is actively trafficked to regions distal from the infusion site. In addition to neuronal transduction, a significant nonneuronal cell population was transduced by AAV1 vector; for example, oligodendrocytes in corona radiata and astrocytes in the striatum. We observed a strong humoral and cell-mediated response against AAV1-hrGFP in transduced monkeys irrespective of the anatomic location of the infusion, as evidenced by induction of circulating anti-AAV1 and anti-hrGFP antibodies, as well as infiltration of CD4+ lymphocytes and upregulation of MHC-II in regions infused with vector. We conclude that transduction of antigen-presenting cells within the CNS is a likely cause of this response and that caution is warranted when foreign transgenes are used as reporters in gene therapy studies with vectors with broader tropism than AAV2. PMID:19292604

Attenuated Listeria monocytogenes vectors overcome suppressive plasma factors during HIV infection to stimulate myeloid dendritic cells to promote adaptive immunity and reactivation of latent virus.

PubMed

Miller, Elizabeth A; Spadaccia, Meredith R; Norton, Thomas; Demmler, Morgan; Gopal, Ramya; O'Brien, Meagan; Landau, Nathaniel; Dubensky, Thomas W; Lauer, Peter; Brockstedt, Dirk G; Bhardwaj, Nina

2015-01-01

HIV-1 infection is characterized by myeloid dendritic cell (DC) dysfunction, which blunts the responsiveness to vaccine adjuvants. We previously showed that nonviral factors in HIV-seropositive plasma are partially responsible for mediating this immune suppression. In this study we investigated recombinant Listeria monocytogenes (Lm) vectors, which naturally infect and potently activate DCs from seronegative donors, as a means to overcome DC dysfunction associated with HIV infection. Monocyte-derived DCs were cocultured with plasma from HIV-infected donors (HIV-moDCs) to induce a dysregulated state and infected with an attenuated, nonreplicative vaccine strain of Lm expressing full length clade B consensus gag (KBMA Lm-gag). Lm infection stimulated cytokine secretion [interleukin (IL)-12p70, tumor necrosis factor (TNF)-α, and IL-6] and Th-1 skewing of allogeneic naive CD4 T cells by HIV-moDCs, in contrast to the suppressive effects observed by HIV plasma on moDCs on toll-like receptor ligand stimulation. Upon coculture of "killed" but metabolically active (KBMA) Lm-gag-infected moDCs from HIV-infected donors with autologous cells, expansion of polyfunctional, gag-specific CD8(+) T cells was observed. Reactivation of latent proviruses by moDCs following Lm infection was also observed in models of HIV latency in a TNF-α-dependent manner. These findings reveal the unique ability of Lm vectors to contend with dysregulation of HIV-moDCs, while simultaneously possessing the capacity to activate latent virus. Concurrent stimulation of innate and adaptive immunity and disruption of latency may be an approach to reduce the pool of latently infected cells during HIV infection. Further study of Lm vectors as part of therapeutic vaccination and eradication strategies may advance this evolving field.

A Two-Locus Model of the Evolution of Insecticide Resistance to Inform and Optimise Public Health Insecticide Deployment Strategies

PubMed Central

2017-01-01

We develop a flexible, two-locus model for the spread of insecticide resistance applicable to mosquito species that transmit human diseases such as malaria. The model allows differential exposure of males and females, allows them to encounter high or low concentrations of insecticide, and allows selection pressures and dominance values to differ depending on the concentration of insecticide encountered. We demonstrate its application by investigating the relative merits of sequential use of insecticides versus their deployment as a mixture to minimise the spread of resistance. We recover previously published results as subsets of this model and conduct a sensitivity analysis over an extensive parameter space to identify what circumstances favour mixtures over sequences. Both strategies lasted more than 500 mosquito generations (or about 40 years) in 24% of runs, while in those runs where resistance had spread to high levels by 500 generations, 56% favoured sequential use and 44% favoured mixtures. Mixtures are favoured when insecticide effectiveness (their ability to kill homozygous susceptible mosquitoes) is high and exposure (the proportion of mosquitoes that encounter the insecticide) is low. If insecticides do not reliably kill homozygous sensitive genotypes, it is likely that sequential deployment will be a more robust strategy. Resistance to an insecticide always spreads slower if that insecticide is used in a mixture although this may be insufficient to outperform sequential use: for example, a mixture may last 5 years while the two insecticides deployed individually may last 3 and 4 years giving an overall ‘lifespan’ of 7 years for sequential use. We emphasise that this paper is primarily about designing and implementing a flexible modelling strategy to investigate the spread of insecticide resistance in vector populations and demonstrate how our model can identify vector control strategies most likely to minimise the spread of insecticide resistance. PMID:28095406

Confusion, knock-down and kill of Aedes aegypti using metofluthrin in domestic settings: a powerful tool to prevent dengue transmission?

PubMed Central

2013-01-01

Background Dengue control methods are reliant upon control of the vector, primarily Aedes aegypti. Current adulticiding methods in North Queensland include treating premises with residual synthetic pyrethroid insecticides (interior residual spraying; IRS), a laborious, intrusive task. The vapor active synthetic pyrethroid metofluthrin might offer an efficient alternative as some studies indicate that it prevents biting and has strong knockdown effects. However, its expellant and/or irritant effects, longevity, residual activity and the speed with which biting behavior is disrupted have not yet been characterized. Methods We exposed cohorts of Cairns colony (F2-4) Ae. aegypti to rooms (17–24 m3) treated with 5% and 10% AI metofluthrin emanators. Using free-flying and caged populations we measured biting (human landing rate), expulsion through unscreened windows, knockdown and death over periods ranging between a few minutes and 24 hrs. Observations of the behavior of single female Ae. aegypti exposed to metofluthrin were also made. Results Female Ae. aegypti exposed to 5% or 10% metofluthrin formulations were almost entirely inhibited from biting. This was the result of rapid knockdown and mortality (80-90% in less than one hour) and to the behavioral impacts of exposure that, within minutes, caused female Ae. aegypti to become disoriented, stop landing on hosts, and seek resting sites. Exposed mosquitoes did not exhibit any increased propensity to exit treated rooms and the 10% AI resin remained fully active for at least 20 days. Conclusion The new, high-dose, resin formulations of metofluthrin act quickly to prevent biting and to knockdown and kill free-flying female Ae. aegypti in our experimental rooms. There was no evidence that metofluthrin induced escape from treated areas. Resin-based metofluthrin emanators show great potential as a replacement for labor intensive IRS for dengue vector control. PMID:24025232

A high-risk Zika and dengue transmission hub: virus detections in mosquitoes at a Brazilian university campus.

PubMed

Eiras, Alvaro E; Pires, Simone F; Staunton, Kyran M; Paixão, Kelly S; Resende, Marcelo C; Silva, Hilcielly A; Rocha, Isadora G; Oliveira, Bruna A; Peres, Anderson M; Drumond, Betânia P; Ritchie, Scott A

2018-06-22

Zika virus (ZIKV) and dengue virus (DENV) are mosquito-borne flaviviruses prevalent throughout tropical regions. Currently, management of ZIKV and DENV centers on control of the primary vector Aedes aegypti. This vector is highly anthropophilic and is therefore prevalent throughout densely urbanised landscapes. A new passive trap for gravid Ae. aegypti (Gravid Aedes Trap - GAT) was developed for mosquito surveillance. Here the different killing agents and the level of transmission of arboviruses that may occur in mosquitoes sampled by GATs are assessed for the first time. Gravid Aedes traps (GATs) were deployed at the Federal University of Minas Gerais campus, in Belo Horizonte, Brazil to sample Ae. aegypti. Three different killing agents were evaluated within the GATs: sticky cards, long-lasting insecticide-impregnated nets (LLINs) and canola oil. Traps were monitored weekly for 14 weeks then mosquito specimens were identified to the species level and Ae. aegypti catches were pooled and submitted to qRT-PCR assays for to DENV and ZIKV virus detection, followed by Bayesian phylogenetic analysis of the ZIKV. Additionally, comparisons of means were performed on transformed weekly catch data (P = 0.05, t-tests) with the stats package of the R statistical software. In total, 1506 female Ae. aegypti were captured using GATs, with traps using sticky cards catching more mosquito than those using either LLINs or canola oil. Both ZIKV and DENV were detected in Ae. aegypti females captured over several weeks suggesting that this highly populated university campus may have served as a significant transmission hub. The infection rate for ZIKV was present in seven (8.5%) pools from four weeks while DENV was detected in four (4.9%) pools from four weeks. Phylogenetic analysis of ZIKV classified the strain as Asian genotype. The Federal University of Minas Gerais and similar organizations must strongly consider monitoring Ae. aegypti populations and reinforcing personal protection of staff and students during seasons of high mosquito activity.

Most outdoor malaria transmission by behaviourally-resistant Anopheles arabiensis is mediated by mosquitoes that have previously been inside houses.

PubMed

Killeen, Gerry F; Govella, Nicodem J; Lwetoijera, Dickson W; Okumu, Fredros O

2016-04-19

Anopheles arabiensis is stereotypical of diverse vectors that mediate residual malaria transmission globally, because it can feed outdoors upon humans or cattle, or enter but then rapidly exit houses without fatal exposure to insecticidal nets or sprays. Life histories of a well-characterized An. arabiensis population were simulated with a simple but process-explicit deterministic model and relevance to other vectors examined through sensitivity analysis. Where most humans use bed nets, two thirds of An. arabiensis blood feeds and half of malaria transmission events were estimated to occur outdoors. However, it was also estimated that most successful feeds and almost all (>98 %) transmission events are preceded by unsuccessful attempts to attack humans indoors. The estimated proportion of vector blood meals ultimately obtained from humans indoors is dramatically attenuated by availability of alternative hosts, or partial ability to attack humans outdoors. However, the estimated proportion of mosquitoes old enough to transmit malaria, and which have previously entered a house at least once, is far less sensitive to both variables. For vectors with similarly modest preference for cattle over humans and similar ability to evade fatal indoor insecticide exposure once indoors, >80 % of predicted feeding events by mosquitoes old enough to transmit malaria are preceded by at least one house entry event, so long as ≥40 % of attempts to attack humans occur indoors and humans outnumber cattle ≥4-fold. While the exact numerical results predicted by such a simple deterministic model should be considered only approximate and illustrative, the derived conclusions are remarkably insensitive to substantive deviations from the input parameter values measured for this particular An. arabiensis population. This life-history analysis, therefore, identifies a clear, broadly-important opportunity for more effective suppression of residual malaria transmission by An. arabiensis in Africa and other important vectors of residual transmission across the tropics. Improved control of predominantly outdoor residual transmission by An. arabiensis, and other modestly zoophagic vectors like Anopheles darlingi, which frequently enter but then rapidly exit from houses, may be readily achieved by improving existing technology for killing mosquitoes indoors.

Motion of charged particles in a NUTty Einstein-Maxwell spacetime and causality violation

NASA Astrophysics Data System (ADS)

Clément, Gérard; Guenouche, Mourad

2018-06-01

We investigate the motion of electrically charged test particles in spacetimes with closed timelike curves, a subset of the black hole or wormhole Reissner-Nordström-NUT spacetimes without periodic identification of time. We show that, while in the wormhole case there are closed worldlines inside a potential well, the wordlines of initially distant charged observers moving under the action of the Lorentz force can never close or self-intersect. This means that for these observers causality is preserved, which is an instance of our weak chronology protection criterion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Svendsen, Harald G.

In this paper we study a solution of heterotic string theory corresponding to a rotating Kerr-Taub-NUT spacetime. It has an exact CFT description as a heterotic coset model, and a Lagrangian formulation as a gauged WZNW model. It is a generalization of a recently discussed stringy Taub-NUT solution, and is interesting as another laboratory for studying the fate of closed timelike curves and cosmological singularities in string theory. We extend the computation of the exact metric and dilaton to this rotating case, and then discuss some properties of the metric, with particular emphasis on the curvature singularities.

Entanglement between the future and the past in the quantum vacuum.

PubMed

Olson, S Jay; Ralph, Timothy C

2011-03-18

We note that massless fields within the future and past light cone may be quantized as independent systems. The vacuum is shown to be a nonseparable state of these systems, exactly mirroring the known entanglement between the spacelike separated Rindler wedges. This leads to a notion of timelike entanglement. We describe an inertial detector which exhibits a thermal response to the vacuum when switched on at t=0, due to this property. The feasibility of detecting this effect is discussed, with natural experimental parameters appearing at the scale of 100 GHz.

Improved Killing of Ovarian Cancer Stem Cells by Combining a Novel Chimeric Antigen Receptor-Based Immunotherapy and Chemotherapy.

PubMed

Klapdor, Rüdiger; Wang, Shuo; Hacker, Ulrich; Büning, Hildegard; Morgan, Michael; Dörk, Thilo; Hillemanns, Peter; Schambach, Axel

2017-10-01

Ovarian cancer represents the most lethal gynecological cancer. Although cytoreductive chemotherapy and surgery lead to complete macroscopic tumor removal, most of the patients in advanced stages suffer from recurrent disease and subsequently die. This may be explained by the activity of cancer stem cells (CSC), which are a subpopulation of cells with an elevated chemoresistance and an increased capacity for self-renewal and metastatic spread. Specifically targeting these cells by adoptive immunotherapy represents a promising strategy to reduce the risk for recurrent disease. This study selected the widely accepted CSC marker CD133 as a target for a chimeric antigen receptor (CAR)-based immunotherapeutic approach to treat ovarian cancer. A lentiviral vector was generated encoding a third-generation anti-CD133-CAR, and clinically used NK92 cells were transduced. These engineered natural killer (NK) cells showed specific killing against CD133-positive ovarian cancer cell lines and primary ovarian cancer cells cultured from sequential ascites harvests. Additionally, specific activation of these engineered NK cells was demonstrated via interferon-gamma secretion assays. To improve clinical efficacy of ovarian cancer treatment, the effect of the chemotherapeutic agent cisplatin was evaluated together with CAR-transduced NK cell treatment. It was demonstrated that NK cells remain cytotoxic and active under cisplatin treatment and, importantly, that sequential treatment with cisplatin followed by CAR-NK cells led to the strongest killing effect. The specific eradication of ovarian CSCs by anti-CD133-CAR expressing NK92 cells represents a promising strategy and, when confirmed in vivo, shall be the basis of future clinical studies with the aim to prevent recurrent disease.

Natural variation in virulence of the entomopathogenic fungus Beauveria bassiana against malaria mosquitoes.

PubMed

Valero-Jiménez, Claudio A; Debets, Alfons J M; van Kan, Jan A L; Schoustra, Sijmen E; Takken, Willem; Zwaan, Bas J; Koenraadt, Constantianus J M

2014-12-06

Insecticide resistance is greatly hampering current efforts to control malaria and therefore alternative methods are needed. Entomopathogenic fungi have been proposed as an alternative with a special focus on the cosmopolitan species Beauveria bassiana. However, few studies have analysed the effects of natural variation within fungal isolates on mosquito survival, and the implications and possible exploitation for malaria control. Laboratory bioassays were performed on adult female mosquitoes (Anopheles coluzzii) with spores from 29 isolates of B. bassiana, originating from different parts of the world. In addition, phenotypic characteristics of the fungal isolates such as sporulation, spore size and growth rate were studied to explore their relationship with virulence. All tested isolates of B. bassiana killed An. coluzzii mosquitoes, and the rate at which this happened differed significantly among the isolates. The risk of mosquitoes dying was around ten times higher when they were exposed to the most virulent as compared to the least virulent isolate. There was significant variation among isolates in spore size, growth rate and sporulation, but none of these morphological characteristics were correlated, and thus predictive, for the ability of the fungal isolate to kill malaria mosquitoes. This study shows that there is a wide natural variation in virulence of isolates of B. bassiana, and that selecting an appropriate fungal isolate is highly relevant in killing and thus controlling malaria mosquitoes, particularly if used as part of an integrated vector management strategy. Also, the wide variation observed in virulence offers the opportunity to better understand the molecular and genetic mechanisms that drive this variation and thus to address the potential development of resistance against entomopathogenic fungi.

Spinning particles in vacuum spacetimes of different curvature types: Natural reference tetrads and massless particles

NASA Astrophysics Data System (ADS)

Semerák, O.

2015-12-01

In a previous paper, we considered the motion of massive spinning test particles in the "pole-dipole" approximation, as described by the Mathisson-Papapetrou-Dixon (MPD) equations and examined its properties in dependence on the spin supplementary condition. We decomposed the equations in the orthonormal tetrad based on the timelike vector fixing the spin condition and on the corresponding spin, while representing the curvature in terms of the Weyl scalars obtained in the Newman-Penrose null tetrad naturally associated with the orthonormal one; the projections thus obtained did not contain the Weyl scalars Ψ0 and Ψ4. In the present paper, we choose the interpretation tetrad in a different way, attaching it to the tangent uμ of the worldline representing the history of the spinning body. Actually two tetrads are suggested, both given "intrinsically" by the problem and each of them incompatible with one specific spin condition. The decomposition of the MPD equation, again supplemented by writing its right-hand side in terms of the Weyl scalars, is slightly less efficient than in the massive case, because uμ cannot be freely chosen (in contrast to Vμ) and so the uμ-based tetrad is less flexible. In the second part of this paper, a similar analysis is performed for massless spinning particles; in particular, a certain intrinsic interpretation tetrad is again found. The respective decomposition of the MPD equation of motion is considerably simpler than in the massive case, containing only Ψ1 and Ψ2 scalars and not the cosmological constant. An option to span the spin-bivector eigenplane, besides the worldline null tangent, by a main principal null direction of the Weyl tensor can lead to an even simpler result.

Inhibition of Malaria Infection in Transgenic Anopheline Mosquitoes Lacking Salivary Gland Cells

PubMed Central

Kasashima, Katsumi; Sezutsu, Hideki; Matsuoka, Hiroyuki

2016-01-01

Malaria is an important global public health challenge, and is transmitted by anopheline mosquitoes during blood feeding. Mosquito vector control is one of the most effective methods to control malaria, and population replacement with genetically engineered mosquitoes to block its transmission is expected to become a new vector control strategy. The salivary glands are an effective target tissue for the expression of molecules that kill or inactivate malaria parasites. Moreover, salivary gland cells express a large number of molecules that facilitate blood feeding and parasite transmission to hosts. In the present study, we adapted a functional deficiency system in specific tissues by inducing cell death using the mouse Bcl-2-associated X protein (Bax) to the Asian malaria vector mosquito, Anopheles stephensi. We applied this technique to salivary gland cells, and produced a transgenic strain containing extremely low amounts of saliva. Although probing times for feeding on mice were longer in transgenic mosquitoes than in wild-type mosquitoes, transgenic mosquitoes still successfully ingested blood. Transgenic mosquitoes also exhibited a significant reduction in oocyst formation in the midgut in a rodent malaria model. These results indicate that mosquito saliva plays an important role in malaria infection in the midgut of anopheline mosquitoes. The dysfunction in the salivary glands enabled the inhibition of malaria transmission from hosts to mosquito midguts. Therefore, salivary components have potential in the development of new drugs or genetically engineered mosquitoes for malaria control. PMID:27598328

Separation of variables in Maxwell equations in Plebański-Demiański spacetime

NASA Astrophysics Data System (ADS)

Frolov, Valeri P.; Krtouš, Pavel; KubizÅák, David

2018-05-01

A new method for separating variables in the Maxwell equations in four- and higher-dimensional Kerr-(A)dS spacetimes proposed recently by Lunin is generalized to any off-shell metric that admits a principal Killing-Yano tensor. The key observation is that Lunin's ansatz for the vector potential can be formulated in a covariant form—in terms of the principal tensor. In particular, focusing on the four-dimensional case we demonstrate separability of Maxwell's equations in the Kerr-NUT-(A)dS and the Plebański-Demiański family of spacetimes. The new method of separation of variables is quite different from the standard approach based on the Newman-Penrose formalism.

Dynamical boson stars.

PubMed

Liebling, Steven L; Palenzuela, Carlos

2017-01-01

The idea of stable, localized bundles of energy has strong appeal as a model for particles. In the 1950s, John Wheeler envisioned such bundles as smooth configurations of electromagnetic energy that he called geons , but none were found. Instead, particle-like solutions were found in the late 1960s with the addition of a scalar field, and these were given the name boson stars . Since then, boson stars find use in a wide variety of models as sources of dark matter, as black hole mimickers, in simple models of binary systems, and as a tool in finding black holes in higher dimensions with only a single Killing vector. We discuss important varieties of boson stars, their dynamic properties, and some of their uses, concentrating on recent efforts.

Catenotaenia dendritica (Cestoda: Catenotaeniidae) and Three Ectoparasite Species in the Red Squirrel, Sciurus vulgaris, from Cheongju, Korea

PubMed Central

Choe, Seongjun; Lee, Dongmin; Park, Hansol; Jeon, Hyeong-Kyu; Lee, Youngsun; Na, Ki-Jeong; Lee, In-Yong; Eom, Keeseon S.

2016-01-01

Parasites are recorded from the red squirrel, Sciurus vulgaris, from Cheongju, the Republic of Korea. A total of 5 road-killed squirrels were thoroughly examined for internal and external parasites from November 2011 to May 2014. Total 4 parasite species, including 1 tapeworm and 3 ectoparasite species were recovered. They were morphologically identified as Catenotaenia dendritica (Cestoda: Catenotaeniidae), Hirstionyssus sciurinus, Leptotrombidium pallidum, and Ceratophyllus (Monopsyllus) indages. Among them, C. dendritica and H. sciurinus are recorded for the first time in the Korean parasite fauna. In addition, the possibility that the red squirrel could act as a reservoir host for a zoonotic disease like tsutsugamushi disease with L. pallidum as its vector has been raised. PMID:27658604

Rhodococcus equi (Prescottella equi) vaccines; the future of vaccine development.

PubMed

Giles, C; Vanniasinkam, T; Ndi, S; Barton, M D

2015-09-01

For decades researchers have been targeting prevention of Rhodococcus equi (Rhodococcus hoagui/Prescottella equi) by vaccination and the horse breeding industry has supported the ongoing efforts by researchers to develop a safe and cost effective vaccine to prevent disease in foals. Traditional vaccines including live, killed and attenuated (physical and chemical) vaccines have proved to be ineffective and more modern molecular-based vaccines including the DNA plasmid, genetically attenuated and subunit vaccines have provided inadequate protection of foals. Newer, bacterial vector vaccines have recently shown promise for R. equi in the mouse model. This article describes the findings of key research in R. equi vaccine development and looks at alternative methods that may potentially be utilised. © 2014 EVJ Ltd.

Catenotaenia dendritica (Cestoda: Catenotaeniidae) and Three Ectoparasite Species in the Red Squirrel, Sciurus vulgaris, from Cheongju, Korea.

PubMed

Choe, Seongjun; Lee, Dongmin; Park, Hansol; Jeon, Hyeong-Kyu; Lee, Youngsun; Na, Ki-Jeong; Lee, In-Yong; Eom, Keeseon S

2016-08-01

Parasites are recorded from the red squirrel, Sciurus vulgaris, from Cheongju, the Republic of Korea. A total of 5 road-killed squirrels were thoroughly examined for internal and external parasites from November 2011 to May 2014. Total 4 parasite species, including 1 tapeworm and 3 ectoparasite species were recovered. They were morphologically identified as Catenotaenia dendritica (Cestoda: Catenotaeniidae), Hirstionyssus sciurinus, Leptotrombidium pallidum, and Ceratophyllus (Monopsyllus) indages. Among them, C. dendritica and H. sciurinus are recorded for the first time in the Korean parasite fauna. In addition, the possibility that the red squirrel could act as a reservoir host for a zoonotic disease like tsutsugamushi disease with L. pallidum as its vector has been raised.

Microbial pathogens in raw pork, chicken, and beef: benefit estimates for control using irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, T.

1985-12-01

Various control procedures have been suggested for reducing foodborne infectious diseases. Receiving considerable attention is irradiation. This report estimates the medical and wage (or productivity) benefits associated with prevention of five human diseases transmitted by beef, pork, and chicken. (These diseases can also be transmitted by other vectors, such as eggs, milk, and pets. But these sources are not included in the analysis.) All of these foodborne infectious diseases - salmonellosis, campylobacteriosis, trichinosis, tapeworm, and toxoplasmosis - could be significantly reduced by irradiating meat and poultry. The Food and Drug Administration (FDA) has just approved irradiation of pork to preventmore » trichinosis (50FR 29658-59) and is considering approval of irradiation of chicken to kill Salmonella. 22 references.« less

Bacteriophages encode factors required for protection in a symbiotic mutualism.

PubMed

Oliver, Kerry M; Degnan, Patrick H; Hunter, Martha S; Moran, Nancy A

2009-08-21

Bacteriophages are known to carry key virulence factors for pathogenic bacteria, but their roles in symbiotic bacteria are less well understood. The heritable symbiont Hamiltonella defensa protects the aphid Acyrthosiphon pisum from attack by the parasitoid Aphidius ervi by killing developing wasp larvae. In a controlled genetic background, we show that a toxin-encoding bacteriophage is required to produce the protective phenotype. Phage loss occurs repeatedly in laboratory-held H. defensa-infected aphid clonal lines, resulting in increased susceptibility to parasitism in each instance. Our results show that these mobile genetic elements can endow a bacterial symbiont with benefits that extend to the animal host. Thus, phages vector ecologically important traits, such as defense against parasitoids, within and among symbiont and animal host lineages.

Consistent Pauli reduction on group manifolds

DOE PAGES

Baguet, A.; Pope, Christopher N.; Samtleben, H.

2016-01-01

We prove an old conjecture by Duff, Nilsson, Pope and Warner asserting that the NSNS sector of supergravity (and more general the bosonic string) allows for a consistent Pauli reduction on any d-dimensional group manifold G, keeping the full set of gauge bosons of the G×G isometry group of the bi-invariant metric on G. The main tool of the construction is a particular generalised Scherk–Schwarz reduction ansatz in double field theory which we explicitly construct in terms of the group's Killing vectors. Examples include the consistent reduction from ten dimensions on S3×S3 and on similar product spaces. The construction ismore » another example of globally geometric non-toroidal compactifications inducing non-geometric fluxes.« less

New frontiers in oncolytic viruses: optimizing and selecting for virus strains with improved efficacy

PubMed Central

2018-01-01

Oncolytic viruses have demonstrated selective replication and killing of tumor cells. Different types of oncolytic viruses – adenoviruses, alphaviruses, herpes simplex viruses, Newcastle disease viruses, rhabdoviruses, Coxsackie viruses, and vaccinia viruses – have been applied as either naturally occurring or engineered vectors. Numerous studies in animal-tumor models have demonstrated substantial tumor regression and prolonged survival rates. Moreover, clinical trials have confirmed good safety profiles and therapeutic efficacy for oncolytic viruses. Most encouragingly, the first cancer gene-therapy drug – Gendicine, based on oncolytic adenovirus type 5 – was approved in China. Likewise, a second-generation oncolytic herpes simplex virus-based drug for the treatment of melanoma has been registered in the US and Europe as talimogene laherparepvec. PMID:29445265

Prevention of communicable diseases after disaster: A review

PubMed Central

Jafari, Najmeh; Shahsanai, Armindokht; Memarzadeh, Mehrdad; Loghmani, Amir

2011-01-01

Natural disasters are tragic incidents originating from atmospheric, geologic and hydrologic changes. In recent decades, millions of people have been killed by natural disasters, resulting in economic damages. Natural and complex disasters dramatically increase the mortality and morbidity due to communicable diseases. The major causes of communicable disease in disasters are categorized into four sections: Infections due to contaminated food and water, respiratory infections, vector and insect-borne diseases, and infections due to wounds and injuries. With appropriate intervention, high morbidity and mortality resulting from communicable diseases can be avoided to a great deal. This review article tries to provide the best recommendations for planning and preparing to prevent communicable disease after disaster in two phases: before disaster and after disaster. PMID:22279466

Cytokine-induced killer cells eradicate bone and soft-tissue sarcomas.

PubMed

Sangiolo, Dario; Mesiano, Giulia; Gammaitoni, Loretta; Leuci, Valeria; Todorovic, Maja; Giraudo, Lidia; Cammarata, Cristina; Dell'Aglio, Carmine; D'Ambrosio, Lorenzo; Pisacane, Alberto; Sarotto, Ivana; Miano, Sara; Ferrero, Ivana; Carnevale-Schianca, Fabrizio; Pignochino, Ymera; Sassi, Francesco; Bertotti, Andrea; Piacibello, Wanda; Fagioli, Franca; Aglietta, Massimo; Grignani, Giovanni

2014-01-01

Unresectable metastatic bone sarcoma and soft-tissue sarcomas (STS) are incurable due to the inability to eradicate chemoresistant cancer stem-like cells (sCSC) that are likely responsible for relapses and drug resistance. In this study, we investigated the preclinical activity of patient-derived cytokine-induced killer (CIK) cells against autologous bone sarcoma and STS, including against putative sCSCs. Tumor killing was evaluated both in vitro and within an immunodeficient mouse model of autologous sarcoma. To identify putative sCSCs, autologous bone sarcoma and STS cells were engineered with a CSC detector vector encoding eGFP under the control of the human promoter for OCT4, a stem cell gene activated in putative sCSCs. Using CIK cells expanded from 21 patients, we found that CIK cells efficiently killed allogeneic and autologous sarcoma cells in vitro. Intravenous infusion of CIK cells delayed autologous tumor growth in immunodeficient mice. Further in vivo analyses established that CIK cells could infiltrate tumors and that tumor growth inhibition occurred without an enrichment of sCSCs relative to control-treated animals. These results provide preclinical proof-of-concept for an effective strategy to attack autologous sarcomas, including putative sCSCs, supporting the clinical development of CIK cells as a novel class of immunotherapy for use in settings of untreatable metastatic disease.

Entomopathogenic fungi for mosquito control: A review

PubMed Central

Scholte, Ernst-Jan; Knols, Bart G.J.; Samson, Robert A.; Takken, Willem

2004-01-01

Fungal diseases in insects are common and widespread and can decimate their populations in spectacular epizootics. Virtually all insect orders are susceptible to fungal diseases, including Dipterans. Fungal pathogens such as Lagenidium, Coelomomyces and Culicinomyces are known to affect mosquito populations, and have been studied extensively. There are, however, many other fungi that infect and kill mosquitoes at the larval and/or adult stage. The discovery, in 1977, of the selective mosquito-pathogenic bacterium Bacillus thuringiensis Berliner israelensis (Bti) curtailed widespread interest in the search for other suitable biological control agents. In recent years interest in mosquito-killing fungi is reviving, mainly due to continuous and increasing levels of insecticide resistance and increasing global risk of mosquito-borne diseases. This review presents an update of published data on mosquito-pathogenic fungi and mosquito-pathogen interactions, covering 13 different fungal genera. Notwithstanding the potential of many fungi as mosquito control agents, only a handful have been commercialized and are marketed for use in abatement programs. We argue that entomopathogenic fungi, both new and existing ones with renewed/improved efficacies may contribute to an expansion of the limited arsenal of effective mosquito control tools, and that they may contribute in a significant and sustainable manner to the control of vector-borne diseases such as malaria, dengue and filariasis. PMID:15861235

Correction of both spontaneous and DEB-induced chromosome instability in Fanconi anemia FA-C cells by FACC cDNA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stavropoulos, D.J.; Tomkins, D.J.; Allingham-Hawkins, D.J.

1994-09-01

Cells from all four Fanconi anemia complementation groups show hypersensitivity to cell-killing by mitomycin C (MMC), diepoxybutane (DEB) and other DNA cross-linking agents, and increased spontaneous and DEB-induced chromosome aberrations (CA). The extent of these phenotypes varies between lymphoblastoid cell lines from different complementation groups. Our data showed that the difference in MMC hypersensitivity and DEB-CA was not always coupled. While 230N (FA-B) had higher DEB-induced CA/cell than 536N (FA-C) (7.42 vs. 4.46 respectively), that latter was much more sensitive to cell-killing by MMC (dose at 10% survival, D{sub 10}: 5.2 vs. 1.2 ng/ml respectively). Strathdes et al. (1992) clonedmore » a cDNA Fanconi anemia complementation group C (FACC) which complemented the hypersensitivity to MMC and DEB cell-killing of FA-C cells (536N) but not cells from the other three complementation groups. The present study was initiated to determine whether chromosome instability in 536N is also complemented by the FACC (FAC3) cDNA. The pREP4-FAC3 vector was transfected into 536N and transfectants selected with hygromycin B. The DEB D{sub 10} of 536N (1.0 {mu}M) was corrected to the control level (16.2 {mu}M for 3TO) by FACC (15.1 {mu}M for 536N-FACC), as previously demonstrated. Chromosome instability (cab, cse, ctb, cte) was determined without and with 0.1 {mu}g/ml DEB treatment. Spontaneous CA of 536N (0.30 aberrations/cell) was corrected to the control level (0.04 for 3TO) by FACC (0.06 for 536N-FACC). Similarly, the DEB-induced CA was corrected (2.74 for 536N vs. 0.06 and 0.02 for 3TO and 536N-FACC respectively). Thus, at least for FA complementation group C, hypersensitivity to cell-killing and chromosome instability are not dissociated and are most likely caused by the same gene defect.« less

Nearly extremal apparent horizons in simulations of merging black holes

NASA Astrophysics Data System (ADS)

Lovelace, Geoffrey; Scheel, Mark; Owen, Robert; Giesler, Matthew; Katebi, Reza; Szilagyi, Bela; Chu, Tony; Demos, Nicholas; Hemberger, Daniel; Kidder, Lawrence; Pfeiffer, Harald; Afshari, Nousha; SXS Collaboration

2015-04-01

The spin S of a Kerr black hole is bounded by the surface area A of its apparent horizon: 8 πS <= A . We present recent results (arXiv:1411.7297) for the extremality of apparent horizons for merging, rapidly rotating black holes with equal masses and equal spins aligned with the orbital angular momentum. Measuring the area and (using approximate Killing vectors) the spin on the individual and common apparent horizons, we find that the inequality 8 πS < A is satisfied but is very close to equality on the common apparent horizon at the instant it first appears--even for initial spins as large as S /M2 = 0 . 994 . We compute the smallest value e0 that Booth and Fairhurst's extremality parameter can take for any scaling of the horizon's null normal vectors, concluding that the common horizons are at least moderately close to extremal just after they appear. We construct binary-black-hole initial data with marginally trapped surfaces with 8 πS > A and e0 > 1 , but these surfaces are always surrounded by apparent horizons with 8 πS < A and e0 < 1 .

Transfer of a gene encoding the anticandidal protein histatin 3 to salivary glands.

PubMed

O'Connell, B C; Xu, T; Walsh, T J; Sein, T; Mastrangeli, A; Crystal, R G; Oppenheim, F G; Baum, B J

1996-12-01

Mucosal candidiasis, the most common opportunistic fungal infection in human immunodeficiency virus (HIV)-infected patients, is an early sign of clinically overt acquired immunodeficiency syndrome (AIDS) and an important cause of morbidity, particularly in HIV-infected children. The appearance of azole-resistant strains of Candida albicans had made clinical management of candidiasis increasingly difficult. We propose a novel approach to the management of candidal infections that involves the use of naturally occurring antifungal proteins, such as the histatins. Histatins are a family of small proteins that are secreted in human saliva. We have constructed recombinant adenovirus vectors that contain the histatin 3 cDNA. These vectors are capable of directing the expression of histatin 3 in the saliva of rats at up to 1,045 micrograms/ml, well above the levels found in normal human saliva. The adenovirus-directed histatin demonstrated a 90% candidacidal effect in the timed-kill assay against both fluconazole-susceptible and fluconazole-resistant strains of C. albicans and inhibited germination by 45% in the same strains. These studies suggest that a gene transfer approach to overexpress naturally occurring antifungal proteins may be useful in the management of mucosal candidiasis.

Developing live vaccines against Yersinia pestis

PubMed Central

Sun, Wei; Roland, Kenneth L.; Curtiss, Roy

2014-01-01

Three great plague pandemics caused by the gram-negative bacterium Yersinia pestis have killed nearly 200 million people and it has been linked to biowarfare in the past. Plague is endemic in many parts of the world. In addition, the risk of plague as a bioweapon has prompted increased research to develop plague vaccines against this disease. Injectable subunit vaccines are being developed in the United States and United Kingdom. However, the live attenuated Y. pestis-EV NIIEG strain has been used as a vaccine for more than 70 years in the former Soviet Union and in some parts of Asia and provides a high degree of efficacy against plague. This vaccine has not gained general acceptance because of safety concerns. In recent years, modern molecular biological techniques have been applied to Y. pestis to construct strains with specific defined mutations designed to create safe, immunogenic vaccines with potential for use in humans and as bait vaccines to reduce the load of Y. pestis in the environment. In addition, a number of live, vectored vaccines have been reported using attenuated viral vectors or attenuated Salmonella strains to deliver plague antigens. Here we summarize the progress of live attenuated vaccines against plague. PMID:21918302

An exact solution to the Einstein-Maxwell equations representing a nonspherical, highly charged object

NASA Astrophysics Data System (ADS)

Menon, Govind K.

The Reissner-Nordstrom solution possesses a naked singularity when e2 > m2, where m is the mass and e is the net charge of the system. Also, the singularity at r = 0 is repulsive (i.e., no timelike geodesics (neutral particles) can reach the singularity). These unusual properties of the Reissner-Nordstrom geometry are considered as an accident resulting from the highly symmetric nature of the space-time. Here we wish to generalize the condition of spherical symmetry to axial symmetry and to probe into the issues of naked singularity and gravitational repulsion. To do this, we must construct a nonspherical solution to the Einstein-Maxwell set of equations in the event that e2 > m2. The Erez-Rosen extension of the vacuum Schwarzschild solution to the non-spherical case gave one of the first physically significant solutions of the Einstein field equations. Nonvacuum extensions of the Erez-Rosen solution representing a non-spherical mass containing a very high net charge (i.e., when e2 > m2) will be discussed. The special case of spherical symmetry, as would be expected, results in the Reissner-Nordstrom solution. The search for the physical singularities involves the calculation of a nontrivial scalar constructed from the Riemann curvature tensor. As it turns out, the resulting geometry does indeed possess a naked singularity. In addition, the space-time also entertains gravitational repulsion. However, unlike the Reissner-Nordstrom solution, it has been found that all timelike geodesics are not necessarily repelled from the origin.

Nucleon form factors in dispersively improved chiral effective field theory. II. Electromagnetic form factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alarcon, J. M.; Weiss, C.

We study the nucleon electromagnetic form factors (EM FFs) using a recently developed method combining Chiral Effective Field Theory (more » $$\\chi$$EFT) and dispersion analysis. The spectral functions on the two-pion cut at $$t > 4 M_\\pi^2$$ are constructed using the elastic unitarity relation and an $N/D$ representation. $$\\chi$$EFT is used to calculate the real unctions $$J_\\pm^1 (t) = f_\\pm^1(t)/F_\\pi(t)$$ (ratios of the complex $$\\pi\\pi \\rightarrow N \\bar N$$ partial-wave amplitudes and the timelike pion FF), which are free of $$\\pi\\pi$$ rescattering. Rescattering effects are included through the empirical timelike pion FF $$|F_\\pi(t)|^2$$. The method allows us to compute the isovector EM spectral functions up to $$t \\sim 1$$ GeV$^2$ with controlled accuracy (LO, NLO, and partial N2LO). With the spectral functions we calculate the isovector nucleon EM FFs and their derivatives at $t = 0$ (EM radii, moments) using subtracted dispersion relations. We predict the values of higher FF derivatives with minimal uncertainties and explain their collective behavior. Finally, we estimate the individual proton and neutron FFs by adding an empirical parametrization of the isoscalar sector. Excellent agreement with the present low-$Q^2$ FF data is achieved up to $$\\sim$$0.5 GeV$^2$ for $$G_E$$, and up to $$\\sim$$0.2 GeV$^2$ for $$G_M$$. Our results can be used to guide the analysis of low-$Q^2$ elastic scattering data and the extraction of the proton charge radius.« less

Nucleon form factors in dispersively improved chiral effective field theory. II. Electromagnetic form factors

DOE PAGES

Alarcon, J. M.; Weiss, C.

2018-05-08

We study the nucleon electromagnetic form factors (EM FFs) using a recently developed method combining Chiral Effective Field Theory (more » $$\\chi$$EFT) and dispersion analysis. The spectral functions on the two-pion cut at $$t > 4 M_\\pi^2$$ are constructed using the elastic unitarity relation and an $N/D$ representation. $$\\chi$$EFT is used to calculate the real unctions $$J_\\pm^1 (t) = f_\\pm^1(t)/F_\\pi(t)$$ (ratios of the complex $$\\pi\\pi \\rightarrow N \\bar N$$ partial-wave amplitudes and the timelike pion FF), which are free of $$\\pi\\pi$$ rescattering. Rescattering effects are included through the empirical timelike pion FF $$|F_\\pi(t)|^2$$. The method allows us to compute the isovector EM spectral functions up to $$t \\sim 1$$ GeV$^2$ with controlled accuracy (LO, NLO, and partial N2LO). With the spectral functions we calculate the isovector nucleon EM FFs and their derivatives at $t = 0$ (EM radii, moments) using subtracted dispersion relations. We predict the values of higher FF derivatives with minimal uncertainties and explain their collective behavior. Finally, we estimate the individual proton and neutron FFs by adding an empirical parametrization of the isoscalar sector. Excellent agreement with the present low-$Q^2$ FF data is achieved up to $$\\sim$$0.5 GeV$^2$ for $$G_E$$, and up to $$\\sim$$0.2 GeV$^2$ for $$G_M$$. Our results can be used to guide the analysis of low-$Q^2$ elastic scattering data and the extraction of the proton charge radius.« less

On the self-force in Bopp-Podolsky electrodynamics

NASA Astrophysics Data System (ADS)

Gratus, Jonathan; Perlick, Volker; Tucker, Robin W.

2015-10-01

In the classical vacuum Maxwell-Lorentz theory the self-force of a charged point particle is infinite. This makes classical mass renormalization necessary and, in the special relativistic domain, leads to the Abraham-Lorentz-Dirac equation of motion possessing unphysical run-away and pre-acceleration solutions. In this paper we investigate whether the higher-order modification of classical vacuum electrodynamics suggested by Bopp, Landé, Thomas and Podolsky in the 1940s, can provide a solution to this problem. Since the theory is linear, Green-function techniques enable one to write the field of a charged point particle on Minkowski spacetime as an integral over the particle’s history. By introducing the notion of timelike worldlines that are ‘bounded away from the backward light-cone’ we are able to prescribe criteria for the convergence of such integrals. We also exhibit a timelike worldline yielding singular fields on a lightlike hyperplane in spacetime. In this case the field is mildly singular at the event where the particle crosses the hyperplane. Even in the case when the Bopp-Podolsky field is bounded, it exhibits a directional discontinuity as one approaches the point particle. We describe a procedure for assigning a value to the field on the particle worldline which enables one to define a finite Lorentz self-force. This is explicitly derived leading to an integro-differential equation for the motion of the particle in an external electromagnetic field. We conclude that any worldline solutions to this equation belonging to the categories discussed in the paper have continuous four-velocities.

Squeezed states, time-energy uncertainty relation, and Feynman's rest of the universe

NASA Technical Reports Server (NTRS)

Han, D.; Kim, Y. S.; Noz, Marilyn E.

1992-01-01

Two illustrative examples are given for Feynman's rest of the universe. The first example is the two-mode squeezed state of light where no measurement is taken for one of the modes. The second example is the relativistic quark model where no measurement is possible for the time-like separation fo quarks confined in a hadron. It is possible to illustrate these examples using the covariant oscillator formalism. It is shown that the lack of symmetry between the position-momentum and time-energy uncertainty relations leads to an increase in entropy when the system is different Lorentz frames.

Comparing an analytical spacetime metric for a merging binary to a fully nonlinear numerical evolution using curvature scalars

NASA Astrophysics Data System (ADS)

Sadiq, Jam; Zlochower, Yosef; Nakano, Hiroyuki

2018-04-01

We introduce a new geometrically invariant prescription for comparing two different spacetimes based on geodesic deviation. We use this method to compare a family of recently introduced analytical spacetime representing inspiraling black-hole binaries to fully nonlinear numerical solutions to the Einstein equations. Our method can be used to improve analytical spacetime models by providing a local measure of the effects that violations of the Einstein equations will have on timelike geodesics, and indirectly, gas dynamics. We also discuss the advantages and limitations of this method.

Uniform circular motion in general relativity: existence and extendibility of the trajectories

NASA Astrophysics Data System (ADS)

de la Fuente, Daniel; Romero, Alfonso; Torres, Pedro J.

2017-06-01

The concept of uniform circular motion in a general spacetime is introduced as a particular case of a planar motion. The initial value problem of the corresponding differential equation is analysed in detail. Geometrically, an observer that obeys a uniform circular motion is characterized as a Lorentzian helix. The completeness of inextensible trajectories is studied in generalized Robertson-Walker spacetimes and in a relevant family of pp-wave spacetimes. Under reasonable assumptions, the physical interpretation of such results is that a uniform circular observer lives forever, providing the absence of the singularities defined by these timelike curves.

Fluid/gravity correspondence for massive gravity

NASA Astrophysics Data System (ADS)

Pan, Wen-Jian; Huang, Yong-Chang

2016-11-01

In this paper, we investigate the fluid/gravity correspondence in the framework of massive Einstein gravity. Treating the gravitational mass terms as an effective energy-momentum tensor and utilizing the Petrov-like boundary condition on a timelike hypersurface, we find that the perturbation effects of massive gravity in bulk can be completely governed by the incompressible Navier-Stokes equation living on the cutoff surface under the near horizon and nonrelativistic limits. Furthermore, we have concisely computed the ratio of dynamical viscosity to entropy density for two massive Einstein gravity theories, and found that they still saturate the Kovtun-Son-Starinets (KSS) bound.

On the Support of Minimizers of Causal Variational Principles

NASA Astrophysics Data System (ADS)

Finster, Felix; Schiefeneder, Daniela

2013-11-01

A class of causal variational principles on a compact manifold is introduced and analyzed both numerically and analytically. It is proved under general assumptions that the support of a minimizing measure is either completely timelike, or it is singular in the sense that its interior is empty. In the examples of the circle, the sphere and certain flag manifolds, the general results are supplemented by a more detailed and explicit analysis of the minimizers. On the sphere, we get a connection to packing problems and the Tammes distribution. Moreover, the minimal action is estimated from above and below.

Stability of generic thin shells in conformally flat spacetimes

NASA Astrophysics Data System (ADS)

Amirabi, Z.

2017-07-01

Some important spacetimes are conformally flat; examples are the Robertson-Walker cosmological metric, the Einstein-de Sitter spacetime, and the Levi-Civita-Bertotti-Robinson and Mannheim metrics. In this paper we construct generic thin shells in conformally flat spacetime supported by a perfect fluid with a linear equation of state, i.e., p=ω σ . It is shown that, for the physical domain of ω , i.e., 0<ω ≤ 1, such thin shells are not dynamically stable. The stability of the timelike thin shells with the Mannheim spacetime as the outer region is also investigated.

Quantum probe of Hořava-Lifshitz gravity

NASA Astrophysics Data System (ADS)

Gurtug, O.; Mangut, M.

2018-04-01

Particle probe analysis of the Kehagias-Sfetsos black hole spacetime of Hořava-Lifshitz gravity is extended to wave probe analysis within the framework of quantum mechanics. The time-like naked singularity that develops when ωM2 < 1/2 is probed with quantum fields obeying Klein-Gordon and Chandrasekhar-Dirac equations. The quantum field probe of the naked singularity has revealed that both the spatial part of the wave and the Hamiltonian operators of Klein-Gordon and Chandrasekhar-Dirac equations are essentially self-adjoint, and thus, the naked singularity in the Kehagias-Sfetsos spacetime becomes quantum mechanically non-singular.

Integrability of spinning particle motion in higher-dimensional rotating black hole spacetimes.

PubMed

Kubizňák, David; Cariglia, Marco

2012-02-03

We study the motion of a classical spinning particle (with spin degrees of freedom described by a vector of Grassmann variables) in higher-dimensional general rotating black hole spacetimes with a cosmological constant. In all dimensions n we exhibit n bosonic functionally independent integrals of spinning particle motion, corresponding to explicit and hidden symmetries generated from the principal conformal Killing-Yano tensor. Moreover, we demonstrate that in 4-, 5-, 6-, and 7-dimensional black hole spacetimes such integrals are in involution, proving the bosonic part of the motion integrable. We conjecture that the same conclusion remains valid in all higher dimensions. Our result generalizes the result of Page et al. [Phys. Rev. Lett. 98, 061102 (2007)] on complete integrability of geodesic motion in these spacetimes.

Formulation and delivery of vaccines: Ongoing challenges for animal management

PubMed Central

Sharma, Sameer; Hinds, Lyn A.

2012-01-01

Development of a commercially successful animal vaccine is not only influenced by various immunological factors, such as type of antigen but also by formulation and delivery aspects. The latter includes the need for a vector or specific delivery system, the choice of route of administration and the nature of the target animal population and their habitat. This review describes the formulation and delivery aspects of various types of antigens such as killed microorganisms, proteins and nucleic acids for the development of efficacious and safe animal vaccines. It also focuses on the challenges associated with the different approaches that might be required for formulating and delivering species specific vaccines, particularly if their intended use is for improved animal management with respect to disease and/or reproductive control. PMID:23248557

Primed for death: Law enforcement-citizen homicides, social media, and retaliatory violence.

PubMed

Bejan, Vladimir; Hickman, Matthew; Parkin, William S; Pozo, Veronica F

2018-01-01

We examine whether retaliatory violence exists between law enforcement and citizens while controlling for any social media contagion effect related to prior fatal encounters. Analyzed using a trivariate dynamic structural vector-autoregressive model, daily time-series data over a 21-month period captured the frequencies of police killed in the line of duty, police deadly use of force incidents, and social media coverage. The results support a significant retaliatory violence effect against minorities by police, yet there is no evidence of retaliatory violence against law enforcement officers by minorities. Also, social media coverage of the Black Lives Matter movement increases the risk of fatal victimization to both law enforcement officers and minorities. Possible explanations for these results are based in rational choice and terror management theories.

Bianchi class B spacetimes with electromagnetic fields

NASA Astrophysics Data System (ADS)

Yamamoto, Kei

2012-02-01

We carry out a thorough analysis on a class of cosmological space-times which admit three spacelike Killing vectors of Bianchi class B and contain electromagnetic fields. Using dynamical system analysis, we show that a family of electro-vacuum plane-wave solutions of the Einstein-Maxwell equations is the stable attractor for expanding universes. Phase dynamics are investigated in detail for particular symmetric models. We integrate the system exactly for some special cases to confirm the qualitative features. Some of the obtained solutions have not been presented previously to the best of our knowledge. Finally, based on those analyses, we discuss the relation between those homogeneous models and perturbations of open Friedmann-Lemaitre-Robertson-Walker universes. We argue that the electro-vacuum plane-wave modes correspond to a certain long-wavelength limit of electromagnetic perturbations.

Primed for death: Law enforcement-citizen homicides, social media, and retaliatory violence

PubMed Central

Bejan, Vladimir; Hickman, Matthew; Pozo, Veronica F.

2018-01-01

We examine whether retaliatory violence exists between law enforcement and citizens while controlling for any social media contagion effect related to prior fatal encounters. Analyzed using a trivariate dynamic structural vector-autoregressive model, daily time-series data over a 21-month period captured the frequencies of police killed in the line of duty, police deadly use of force incidents, and social media coverage. The results support a significant retaliatory violence effect against minorities by police, yet there is no evidence of retaliatory violence against law enforcement officers by minorities. Also, social media coverage of the Black Lives Matter movement increases the risk of fatal victimization to both law enforcement officers and minorities. Possible explanations for these results are based in rational choice and terror management theories. PMID:29320548

Antibody-functionalized porous silicon nanoparticles for vectorization of hydrophobic drugs.

PubMed

Secret, Emilie; Smith, Kevin; Dubljevic, Valentina; Moore, Eli; Macardle, Peter; Delalat, Bahman; Rogers, Mary-Louise; Johns, Terrance G; Durand, Jean-Olivier; Cunin, Frédérique; Voelcker, Nicolas H

2013-05-01

We describe the preparation of biodegradable porous silicon nanoparticles (pSiNP) functionalized with cancer cell targeting antibodies and loaded with the hydrophobic anti-cancer drug camptothecin. Orientated immobilization of the antibody on the pSiNP is achieved using novel semicarbazide based bioconjugate chemistry. To demonstrate the generality of this targeting approach, the three antibodies MLR2, mAb528 and Rituximab are used, which target neuroblastoma, glioblastoma and B lymphoma cells, respectively. Successful targeting is demonstrated by means of flow cytometry and immunocytochemistry both with cell lines and primary cells. Cell viability assays after incubation with pSiNPs show selective killing of cells expressing the receptor corresponding to the antibody attached on the pSiNP. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The field efficacy of garlic extract against Dermanyssus gallinae in layer farms of Babol, Iran.

PubMed

Faghihzadeh Gorji, Shohreh; Faghihzadeh Gorji, Sina; Rajabloo, Mohammad

2014-03-01

Dermanyssus gallinae (Acari: Mesostigmata) is the most important hematophagous ectoparasite in layer farms in many countries. The reproduction rate of the parasite is rapid and can be completed in a week under favorable conditions. The parasite has direct and indirect effects on birds. It can also act as a vector for some important pathogens. Many researchers have investigated the effects of essential oils, plant extracts, oriental medicinal plant extracts, and silica against red mite. They can be used as killing agents or repellents. In the present study, the effect of garlic (Allium sativum) extract was investigated for controlling red mite infestation in a layer farm in Babol, North of Iran. Our results showed that the extract was effective and we obtained a 96% success after two successive sprays.

Delivery of chemotherapeutic drugs in tumour cell-derived microparticles.

PubMed

Tang, Ke; Zhang, Yi; Zhang, Huafeng; Xu, Pingwei; Liu, Jing; Ma, Jingwei; Lv, Meng; Li, Dapeng; Katirai, Foad; Shen, Guan-Xin; Zhang, Guimei; Feng, Zuo-Hua; Ye, Duyun; Huang, Bo

2012-01-01

Cellular microparticles are vesicular plasma membrane fragments with a diameter of 100-1,000 nanometres that are shed by cells in response to various physiological and artificial stimuli. Here we demonstrate that tumour cell-derived microparticles can be used as vectors to deliver chemotherapeutic drugs. We show that tumour cells incubated with chemotherapeutic drugs package these drugs into microparticles, which can be collected and used to effectively kill tumour cells in murine tumour models without typical side effects. We describe several mechanisms involved in this process, including uptake of drug-containing microparticles by tumour cells, synthesis of additional drug-packaging microparticles by these cells that contribute to the cytotoxic effect and the inhibition of drug efflux from tumour cells. This study highlights a novel drug delivery strategy with potential clinical application.

Modulation of extracellular matrix in cancer is associated with enhanced tumor cell targeting by bacteriophage vectors.

PubMed

Yata, Teerapong; Lee, Eugene L Q; Suwan, Keittisak; Syed, Nelofer; Asavarut, Paladd; Hajitou, Amin

2015-06-03

Gene therapy has been an attractive paradigm for cancer treatment. However, cancer gene therapy has been challenged by the inherent limitation of vectors that are able to deliver therapeutic genes to tumors specifically and efficiently following systemic administration. Bacteriophage (phage) are viruses that have shown promise for targeted systemic gene delivery. Yet, they are considered poor vectors for gene transfer. Recently, we generated a tumor-targeted phage named adeno-associated virus/phage (AAVP), which is a filamentous phage particle whose genome contains the adeno-associated virus genome. Its effectiveness in delivering therapeutic genes to tumors specifically both in vitro and in vivo has been shown in numerous studies. Despite being a clinically useful vector, a multitude of barriers impede gene transduction to tumor cells. We hypothesized that one such factor is the tumor extracellular matrix (ECM). We used a number of tumor cell lines from different species and histological types in 2D monolayers or 3D multicellular tumor spheroid (MCTS) models. To assess whether the ECM is a barrier to tumor cell targeting by AAVP, we depleted the ECM using collagenase, hyaluronidase, or combination of both. We employed multiple techniques to investigate and quantify the effect of ECM depletion on ECM composition (including collagen type I, hyaluronic acid, fibronectin and laminin), and how AAVP adsorption, internalisation, gene expression and therapeutic efficacy are subsequently affected. Data were analyzed using a student's t test when comparing two groups or one-way ANOVA and post hoc Tukey tests when using more than two groups. We demonstrate that collagenase and hyaluronidase-mediated degradation of tumor ECM affects the composition of collagen, hyaluronic acid and fibronectin. Consequently, AAVP diffusion, internalisation, gene expression and tumor cell killing were enhanced after enzymatic treatment. Our data suggest that enhancement of gene transfer by the AAVP is solely attributed to ECM depletion. We provide substantial evidence that ECM modulation is relevant in clinically applicable settings by using 3D MCTS, which simulates in vivo environments more accurately. Our findings suggest that ECM depletion is an effective strategy to enhance the efficiency of viral vector-guided gene therapy.

Modelling the impact of vector control interventions on Anopheles gambiae population dynamics

PubMed Central

2011-01-01

Background Intensive anti-malaria campaigns targeting the Anopheles population have demonstrated substantial reductions in adult mosquito density. Understanding the population dynamics of Anopheles mosquitoes throughout their whole lifecycle is important to assess the likely impact of vector control interventions alone and in combination as well as to aid the design of novel interventions. Methods An ecological model of Anopheles gambiae sensu lato populations incorporating a rainfall-dependent carrying capacity and density-dependent regulation of mosquito larvae in breeding sites is developed. The model is fitted to adult mosquito catch and rainfall data from 8 villages in the Garki District of Nigeria (the 'Garki Project') using Bayesian Markov Chain Monte Carlo methods and prior estimates of parameters derived from the literature. The model is used to compare the impact of vector control interventions directed against adult mosquito stages - long-lasting insecticide treated nets (LLIN), indoor residual spraying (IRS) - and directed against aquatic mosquito stages, alone and in combination on adult mosquito density. Results A model in which density-dependent regulation occurs in the larval stages via a linear association between larval density and larval death rates provided a good fit to seasonal adult mosquito catches. The effective mosquito reproduction number in the presence of density-dependent regulation is dependent on seasonal rainfall patterns and peaks at the start of the rainy season. In addition to killing adult mosquitoes during the extrinsic incubation period, LLINs and IRS also result in less eggs being oviposited in breeding sites leading to further reductions in adult mosquito density. Combining interventions such as the application of larvicidal or pupacidal agents that target the aquatic stages of the mosquito lifecycle with LLINs or IRS can lead to substantial reductions in adult mosquito density. Conclusions Density-dependent regulation of anopheline larvae in breeding sites ensures robust, stable mosquito populations that can persist in the face of intensive vector control interventions. Selecting combinations of interventions that target different stages in the vector's lifecycle will result in maximum reductions in mosquito density. PMID:21798055

Possibilities and challenges for developing a successful vaccine for leishmaniasis.

PubMed

Srivastava, Saumya; Shankar, Prem; Mishra, Jyotsna; Singh, Sarman

2016-05-12

Leishmaniasis is a vector-borne disease caused by different species of protozoan parasites of the genus Leishmania. It is a major health problem yet neglected tropical diseases, with approximately 350 million people worldwide at risk and more than 1.5 million infections occurring each year. Leishmaniasis has different clinical manifestations, including visceral (VL or kala-azar), cutaneous (CL), mucocutaneous (MCL), diffuse cutaneous (DCL) and post kala-azar dermal leishmaniasis (PKDL). Currently, the only mean to treat and control leishmaniasis is by rational medications and vector control. However, the number of available drugs is limited and even these are either exorbitantly priced, have toxic side effects or prove ineffective due to the emergence of resistant strains. On the other hand, the vector control methods are not so efficient. Therefore, there is an urgent need for developing a safe, effective, and affordable vaccine for the prevention of leishmaniasis. Although in recent years a large body of researchers has concentrated their efforts on this issue, yet only three vaccine candidates have gone for clinical trial, until date. These are: (i) killed vaccine in Brazil for human immunotherapy; (ii) live attenuated vaccine for humans in Uzbekistan; and (iii) second-generation vaccine for dog prophylaxis in Brazil. Nevertheless, there are at least half a dozen vaccine candidates in the pipeline. One can expect that, in the near future, the understanding of the whole genome of Leishmania spp. will expand the vaccine discovery and strategies that may provide novel vaccines. The present review focuses on the development and the status of various vaccines and potential vaccine candidates against leishmaniasis.

PARP-1 depletion in combination with carbon ion exposure significantly reduces MMPs activity and overall increases TIMPs expression in cultured HeLa cells.

PubMed

Ghorai, Atanu; Sarma, Asitikantha; Chowdhury, Priyanka; Ghosh, Utpal

2016-09-22

Hadron therapy is an innovative technique where cancer cells are precisely killed leaving surrounding healthy cells least affected by high linear energy transfer (LET) radiation like carbon ion beam. Anti-metastatic effect of carbon ion exposure attracts investigators into the field of hadron biology, although details remain poor. Poly(ADP-ribose) polymerase-1 (PARP-1) inhibitors are well-known radiosensitizer and several PARP-1 inhibitors are in clinical trial. Our previous studies showed that PARP-1 depletion makes the cells more radiosensitive towards carbon ion than gamma. The purpose of the present study was to investigate combining effects of PARP-1 inhibition with carbon ion exposure to control metastatic properties in HeLa cells. Activities of matrix metalloproteinases-2, 9 (MMP-2, MMP-9) were measured using the gelatin zymography after 85 MeV carbon ion exposure or gamma irradiation (0- 4 Gy) to compare metastatic potential between PARP-1 knock down (HsiI) and control cells (H-vector - HeLa transfected with vector without shRNA construct). Expression of MMP-2, MMP-9, tissue inhibitor of MMPs such as TIMP-1, TIMP-2 and TIMP-3 were checked by immunofluorescence and western blot. Cell death by trypan blue, apoptosis and autophagy induction were studied after carbon ion exposure in each cell-type. The data was analyzed using one way ANOVA and 2-tailed paired-samples T-test. PARP-1 silencing significantly reduced MMP-2 and MMP-9 activities and carbon ion exposure further diminished their activities to less than 3 % of control H-vector. On the contrary, gamma radiation enhanced both MMP-2 and MMP-9 activities in H-vector but not in HsiI cells. The expression of MMP-2 and MMP-9 in H-vector and HsiI showed different pattern after carbon ion exposure. All three TIMPs were increased in HsiI, whereas only TIMP-1 was up-regulated in H-vector after irradiation. Notably, the expressions of all TIMPs were significantly higher in HsiI than H-vector at 4 Gy. Apoptosis was the predominant mode of cell death and no autophagic death was observed. Our study demonstrates for the first time that PARP-1 inhibition in combination with carbon ion synergistically decreases MMPs activity along with overall increase of TIMPs. These data open up the possibilities of improvement of carbon ion therapy with PARP-1 inhibition to control highly metastatic cancers.

Evidence for Personal Protective Measures to Reduce Human Contact With Blacklegged Ticks and for Environmentally Based Control Methods to Suppress Host-Seeking Blacklegged Ticks and Reduce Infection with Lyme Disease Spirochetes in Tick Vectors and Rodent Reservoirs

PubMed Central

Eisen, Lars; Dolan, Marc C.

2018-01-01

In the 1980s, the blacklegged tick, Ixodes scapularis Say, and rodents were recognized as the principal vector and reservoir hosts of the Lyme disease spirochete Borrelia burgdorferi in the eastern United States, and deer were incriminated as principal hosts for I. scapularis adults. These realizations led to pioneering studies aiming to reduce the risk for transmission of B. burgdorferi to humans by attacking host-seeking ticks with acaricides, interrupting the enzootic transmission cycle by killing immatures infesting rodent reservoirs by means of acaricide-treated nesting material, or reducing deer abundance to suppress tick numbers. We review the progress over the past three decades in the fields of: 1) prevention of human–tick contact with repellents and permethrin-treated clothing, and 2) suppression of I. scapularis and disruption of enzootic B. burgdorferi transmission with environmentally based control methods. Personal protective measures include synthetic and natural product-based repellents that can be applied to skin and clothing, permethrin sprays for clothing and gear, and permethrin-treated clothing. A wide variety of approaches and products to suppress I. scapularis or disrupt enzootic B. burgdorferi transmission have emerged and been evaluated in field trials. Application of synthetic chemical acaricides is a robust method to suppress host-seeking I. scapularis ticks within a treated area for at least 6–8 wk. Natural product-based acaricides or entomopathogenic fungi have emerged as alternatives to kill host-seeking ticks for homeowners who are unwilling to use synthetic chemical acaricides. However, as compared with synthetic chemical acaricides, these approaches appear less robust in terms of both their killing efficacy and persistence. Use of rodent-targeted topical acaricides represents an alternative for homeowners opposed to open distribution of acaricides to the ground and vegetation on their properties. This host-targeted approach also provides the benefit of the intervention impacting the entire rodent home range. Rodent-targeted oral vaccines against B. burgdorferi and a rodent-targeted antibiotic bait have been evaluated in laboratory and field trials but are not yet commercially available. Targeting of deer—via deer reduction or treatment of deer with topical acaricides—can provide area-wide suppression of host-seeking I. scapularis. These two deer-targeted approaches combine great potential for protection that impacts the entire landscape with severe problems relating to public acceptance or implementation logistics. Integrated use of two or more methods has unfortunately been evaluated in very few published studies, but additional field evaluations of integrated tick and pathogen strategies are underway. PMID:27439616

Analysis of the Fisher solution

NASA Astrophysics Data System (ADS)

Abdolrahimi, Shohreh; Shoom, Andrey A.

2010-01-01

We study the d-dimensional Fisher solution which represents a static, spherically symmetric, asymptotically flat spacetime with a massless scalar field. The solution has two parameters, the mass M and the “scalar charge” Σ. The Fisher solution has a naked curvature singularity which divides the spacetime manifold into two disconnected parts. The part which is asymptotically flat we call the Fisher spacetime, and another part we call the Fisher universe. The d-dimensional Schwarzschild-Tangherlini solution and the Fisher solution belong to the same theory and are dual to each other. The duality transformation acting in the parameter space (M,Σ) maps the exterior region of the Schwarzschild-Tangherlini black hole into the Fisher spacetime which has a naked timelike singularity, and interior region of the black hole into the Fisher universe, which is an anisotropic expanding-contracting universe and which has two spacelike singularities representing its “big bang” and “big crunch.” The big bang singularity and the singularity of the Fisher spacetime are radially weak in the sense that a 1-dimensional object moving along a timelike radial geodesic can arrive to the singularities intact. At the vicinity of the singularity the Fisher spacetime of nonzero mass has a region where its Misner-Sharp energy is negative. The Fisher universe has a marginally trapped surface corresponding to the state of its maximal expansion in the angular directions. These results and derived relations between geometric quantities of the Fisher spacetime, the Fisher universe, and the Schwarzschild-Tangherlini black hole may suggest that the massless scalar field transforms the black hole event horizon into the naked radially weak disjoint singularities of the Fisher spacetime and the Fisher universe which are “dual to the horizon.”

Analysis of the Fisher solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abdolrahimi, Shohreh; Shoom, Andrey A.

2010-01-15

We study the d-dimensional Fisher solution which represents a static, spherically symmetric, asymptotically flat spacetime with a massless scalar field. The solution has two parameters, the mass M and the 'scalar charge' {Sigma}. The Fisher solution has a naked curvature singularity which divides the spacetime manifold into two disconnected parts. The part which is asymptotically flat we call the Fisher spacetime, and another part we call the Fisher universe. The d-dimensional Schwarzschild-Tangherlini solution and the Fisher solution belong to the same theory and are dual to each other. The duality transformation acting in the parameter space (M,{Sigma}) maps the exteriormore » region of the Schwarzschild-Tangherlini black hole into the Fisher spacetime which has a naked timelike singularity, and interior region of the black hole into the Fisher universe, which is an anisotropic expanding-contracting universe and which has two spacelike singularities representing its 'big bang' and 'big crunch'. The big bang singularity and the singularity of the Fisher spacetime are radially weak in the sense that a 1-dimensional object moving along a timelike radial geodesic can arrive to the singularities intact. At the vicinity of the singularity the Fisher spacetime of nonzero mass has a region where its Misner-Sharp energy is negative. The Fisher universe has a marginally trapped surface corresponding to the state of its maximal expansion in the angular directions. These results and derived relations between geometric quantities of the Fisher spacetime, the Fisher universe, and the Schwarzschild-Tangherlini black hole may suggest that the massless scalar field transforms the black hole event horizon into the naked radially weak disjoint singularities of the Fisher spacetime and the Fisher universe which are 'dual to the horizon'.« less

Nucleon form factors in dispersively improved chiral effective field theory. II. Electromagnetic form factors

NASA Astrophysics Data System (ADS)

Alarcón, J. M.; Weiss, C.

2018-05-01

We study the nucleon electromagnetic form factors (EM FFs) using a recently developed method combining chiral effective field theory (χ EFT ) and dispersion analysis. The spectral functions on the two-pion cut at t >4 Mπ2 are constructed using the elastic unitarity relation and an N /D representation. χ EFT is used to calculate the real functions J±1(t ) =f±1(t ) /Fπ(t ) (ratios of the complex π π →N N ¯ partial-wave amplitudes and the timelike pion FF), which are free of π π rescattering. Rescattering effects are included through the empirical timelike pion FF | Fπ(t) | 2 . The method allows us to compute the isovector EM spectral functions up to t ˜1 GeV2 with controlled accuracy (leading order, next-to-leading order, and partial next-to-next-to-leading order). With the spectral functions we calculate the isovector nucleon EM FFs and their derivatives at t =0 (EM radii, moments) using subtracted dispersion relations. We predict the values of higher FF derivatives, which are not affected by higher-order chiral corrections and are obtained almost parameter-free in our approach, and explain their collective behavior. We estimate the individual proton and neutron FFs by adding an empirical parametrization of the isoscalar sector. Excellent agreement with the present low-Q2 FF data is achieved up to ˜0.5 GeV2 for GE, and up to ˜0.2 GeV2 for GM. Our results can be used to guide the analysis of low-Q2 elastic scattering data and the extraction of the proton charge radius.

Quantum interactions with closed timelike curves and superluminal signaling

NASA Astrophysics Data System (ADS)

Bub, Jeffrey; Stairs, Allen

2014-02-01

There is now a significant body of results on quantum interactions with closed timelike curves (CTCs) in the quantum information literature, for both the Deutsch model of CTC interactions (D-CTCs) and the projective model (P-CTCs). As a consequence, there is a prima facie argument exploiting entanglement that CTC interactions would enable superluminal and, indeed, effectively instantaneous signaling. In cases of spacelike separation between the sender of a signal and the receiver, whether a receiver measures the local part of an entangled state or a disentangled state to access the signal can depend on the reference frame. We propose a consistency condition that gives priority to either an entangled perspective or a disentangled perspective in spacelike-separated scenarios. For D-CTC interactions, the consistency condition gives priority to frames of reference in which the state is disentangled, while for P-CTC interactions the condition selects the entangled state. Using the consistency condition, we show that there is a procedure that allows Alice to signal to Bob in the past via relayed superluminal communications between spacelike-separated Alice and Clio, and spacelike-separated Clio and Bob. This opens the door to time travel paradoxes in the classical domain. Ralph [T. C. Ralph, arXiv:1107.4675 [quant-ph].] first pointed this out for P-CTCs, but we show that Ralph's procedure for a "radio to the past" is flawed. Since both D-CTCs and P-CTCs allow classical information to be sent around a spacetime loop, it follows from a result by Aaronson and Watrous [S. Aaronson and J. Watrous, Proc. R. Soc. A 465, 631 (2009), 10.1098/rspa.2008.0350] for CTC-enhanced classical computation that a quantum computer with access to P-CTCs would have the power of PSPACE, equivalent to a D-CTC-enhanced quantum computer.

Timelike Compton Scattering off the nucleon: observables and experimental perspectives for JLab at 12 GeV

NASA Astrophysics Data System (ADS)

Boër, Marie

2016-03-01

Hard exclusive processes such as photoproduction or electroproduction of photon or meson off the nucleon provide access to the Generalized Parton Distributions (GPDs), in the regime where the scattering amplitude is factorized into a hard and a soft part. GPDs contain the correlation between the longitudinal momentum fraction and the transverse spatial densities of quarks and gluons in the nucleon. Timelike Compton Scattering (TCS) correspond to the reaction γN → γ*N → e+e-N, where the photon is scattered off a quark. It is measured through its interference with the associated Bethe-Heitler process, which has the same final state. TCS allows to access the GPDs and test their universality by comparison to the results obtained with the DVCS process (eN → eγN). Also, results obtained with TCS provide additional independent constrains to the GPDs parameterization. We will present the physical motivations for TCS, with our theoretical predictions for TCS observables and their dependencies. We calculated for JLab 12 GeV energies all the single and double beam and/or target polarization observables off the proton and off the neutron. We will also present the experimental perspectives for the next years at JLab. Two proposals were already accepted at JLab: in Hall B, with the CLAS12 spectrometer, in order to measure the unpolarized cross section and in Hall A, with the SoLID spectrometer, in order to measure the unpolarized cross section and the beam spin asymmetry at high intensity. A Letter Of Intent was also submitted in order to measure the transverse target spin asymmetries in Hall C. We will discuss the merits of this different experiments and present some of the expected results.

Pyrethroid Treatment of Cattle for Tsetse Control: Reducing Its Impact on Dung Fauna

PubMed Central

Vale, Glyn A.; Hargrove, John W.; Chamisa, Andrew; Grant, Ian F.; Torr, Stephen J.

2015-01-01

Background African trypansomiases of humans and animals can be controlled by attacking the vectors, various species of tsetse fly. Treatment of cattle with pyrethroids to kill tsetse as they feed is the most cost-effective method. However, such treatments can contaminate cattle dung, thereby killing the fauna which disperse the dung and so play an important role in soil fertility. Hence there is a need to identify cost-effective methods of treating cattle with minimal impact on dung fauna. Methodology/Principal Findings We used dung beetles to field bioassay the levels of dung contamination following the use of spray and pour-on formulations of deltamethrin, applied to various parts of the body of cattle in Zimbabwe. Results suggested that dung was contaminated by contact with insecticide on the body surface as the cattle defecated, and by ingestion of insecticide as the cattle licked themselves. Death of dung beetles was reduced to negligible levels by using only the spray and applying it to the legs and belly or legs alone, i.e., places where most tsetse feed. Conclusion/Significance The restricted applications suitable for minimising the impact on dung fauna have the collateral benefits of improving the economy and convenience of cattle treatments for tsetse control. The demonstration of collateral benefits is one of the surest ways of promoting environmentally friendly procedures. PMID:25738836

Temephos Resistance in Aedes aegypti in Colombia Compromises Dengue Vector Control

PubMed Central

Grisales, Nelson; Poupardin, Rodolphe; Gomez, Santiago; Fonseca-Gonzalez, Idalyd; Ranson, Hilary; Lenhart, Audrey

2013-01-01

Background Control and prevention of dengue relies heavily on the application of insecticides to control dengue vector mosquitoes. In Colombia, application of the larvicide temephos to the aquatic breeding sites of Aedes aegypti is a key part of the dengue control strategy. Resistance to temephos was recently detected in the dengue-endemic city of Cucuta, leading to questions about its efficacy as a control tool. Here, we characterize the underlying mechanisms and estimate the operational impact of this resistance. Methodology/Principal Findings Larval bioassays of Ae. aegypti larvae from Cucuta determined the temephos LC50 to be 0.066 ppm (95% CI 0.06–0.074), approximately 15× higher than the value obtained from a susceptible laboratory colony. The efficacy of the field dose of temephos at killing this resistant Cucuta population was greatly reduced, with mortality rates <80% two weeks after application and <50% after 4 weeks. Neither biochemical assays nor partial sequencing of the ace-1 gene implicated target site resistance as the primary resistance mechanism. Synergism assays and microarray analysis suggested that metabolic mechanisms were most likely responsible for the temephos resistance. Interestingly, although the greatest synergism was observed with the carboxylesterase inhibitor, DEF, the primary candidate genes from the microarray analysis, and confirmed by quantitative PCR, were cytochrome P450 oxidases, notably CYP6N12, CYP6F3 and CYP6M11. Conclusions/Significance In Colombia, resistance to temephos in Ae. aegypti compromises the duration of its effect as a vector control tool. Several candidate genes potentially responsible for metabolic resistance to temephos were identified. Given the limited number of insecticides that are approved for vector control, future chemical-based control strategies should take into account the mechanisms underlying the resistance to discern which insecticides would likely lead to the greatest control efficacy while minimizing further selection of resistant phenotypes. PMID:24069492

Carbon ion beam triggers both caspase-dependent and caspase-independent pathway of apoptosis in HeLa and status of PARP-1 controls intensity of apoptosis.

PubMed

Ghorai, Atanu; Sarma, Asitikantha; Bhattacharyya, Nitai P; Ghosh, Utpal

2015-04-01

High linear energy transfer (LET) carbon ion beam (CIB) is becoming very promising tool for various cancer treatments and is more efficient than conventional low LET gamma or X-rays to kill malignant or radio-resistant cells, although detailed mechanism of cell death is still unknown. Poly (ADP-ribose) polymerase-1 (PARP-1) is a key player in DNA repair and its inhibitors are well-known as radio-sensitizer for low LET radiation. The objective of our study was to find mechanism(s) of induction of apoptosis by CIB and role of PARP-1 in CIB-induced apoptosis. We observed overall higher apoptosis in PARP-1 knocked down HeLa cells (HsiI) compared with negative control H-vector cells after irradiation with CIB (0-4 Gy). CIB activated both intrinsic and extrinsic pathways of apoptosis via caspase-9 and caspase-8 activation respectively, followed by caspase-3 activation, apoptotic body, nucleosomal ladder formation and sub-G1 accumulation. Apoptosis inducing factor translocation into nucleus in H-vector but not in HsiI cells after CIB irradiation contributed caspase-independent apoptosis. Higher p53 expression was observed in HsiI cells compared with H-vector after exposure with CIB. Notably, we observed about 37 % fall of mitochondrial membrane potential, activation of caspase-9 and caspase-3 and mild activation of caspase-8 without any detectable apoptotic body formation in un-irradiated HsiI cells. We conclude that reduction of PARP-1 expression activates apoptotic signals via intrinsic and extrinsic pathways in un-irradiated cells. CIB irradiation further intensified both intrinsic and extrinsic pathways of apoptosis synergistically along with up-regulation of p53 in HsiI cells resulting overall higher apoptosis in HsiI than H-vector.

Synthetic sex pheromone attracts the leishmaniasis vector Lutzomyia longipalpis to experimental chicken sheds treated with insecticide

PubMed Central

2010-01-01

Background Current strategies for controlling American visceral leishmaniasis (AVL) have been unable to prevent the spread of the disease across Brazil. With no effective vaccine and culling of infected dogs an unpopular and unsuccessful alternative, new tools are urgently needed to manage populations of the sand fly vector, Lutzomyia longipalpis Lutz and Neiva (Diptera: Psychodidae). Here, we test two potential strategies for improving L. longipalpis control using the synthetic sand fly pheromone (±)-9-methylgermacrene-B: the first in conjunction with spraying of animal houses with insecticide, the second using coloured sticky traps. Results Addition of synthetic pheromone resulted in greater numbers of male and female sand flies being caught and killed at experimental chicken sheds sprayed with insecticide, compared to pheromone-less controls. Furthermore, a ten-fold increase in the amount of sex pheromone released from test sheds increased the number of females attracted and subsequently killed. Treating sheds with insecticide alone resulted in a significant decrease in numbers of males attracted to sheds (compared to pre-spraying levels), and a near significant decrease in numbers of females. However, this effect was reversed through addition of synthetic pheromone at the time of insecticide spraying, leading to an increase in number of flies attracted post-treatment. In field trials of commercially available different coloured sticky traps, yellow traps caught more males than blue traps when placed in chicken sheds. In addition, yellow traps fitted with 10 pheromone lures caught significantly more males than pheromone-less controls. However, while female sand flies showed a preference for both blue and yellow pheromone traps sticky traps over white traps in the laboratory, neither colour caught significant numbers of females in chicken sheds, either with or without pheromone. Conclusions We conclude that synthetic pheromone could currently be most effectively deployed for sand fly control through combination with existing insecticide spraying regimes. Development of a standalone pheromone trap remains a possibility, but such devices may require an additional attractive host odour component to be fully effective. PMID:20222954

Symmetry operators of Killing spinors and superalgebras in AdS5

NASA Astrophysics Data System (ADS)

Ertem, Ümit

2016-04-01

We construct the first-order symmetry operators of Killing spinor equation in terms of odd Killing-Yano forms. By modifying the Schouten-Nijenhuis bracket of Killing-Yano forms, we show that the symmetry operators of Killing spinors close into an algebra in AdS5 spacetime. Since the symmetry operator algebra of Killing spinors corresponds to a Jacobi identity in extended Killing superalgebras, we investigate the possible extensions of Killing superalgebras to include higher-degree Killing-Yano forms. We found that there is a superalgebra extension but no Lie superalgebra extension of the Killing superalgebra constructed out of Killing spinors and odd Killing-Yano forms in AdS5 background.

Viral Vector-Based Innovative Approaches to Directly Abolishing Tumorigenic Pluripotent Stem Cells for Safer Regenerative Medicine.

PubMed

Mitsui, Kaoru; Ide, Kanako; Takahashi, Tomoyuki; Kosai, Ken-Ichiro

2017-06-16

Human pluripotent stem cells (hPSCs) are a promising source of regenerative material for clinical applications. However, hPSC transplant therapies pose the risk of teratoma formation and malignant transformation of undifferentiated remnants. These problems underscore the importance of developing technologies that completely prevent tumorigenesis to ensure safe clinical application. Research to date has contributed to establishing safe hPSC lines, improving the efficiency of differentiation induction, and indirectly ensuring the safety of products. Despite such efforts, guaranteeing the clinical safety of regenerative medicine products remains a key challenge. Given the intrinsic genome instability of hPSCs, selective growth advantage of cancer cells, and lessons learned through failures in previous attempts at hematopoietic stem cell gene therapy, conventional strategies are unlikely to completely overcome issues related to hPSC tumorigenesis. Researchers have recently embarked on studies aimed at locating and directly treating hPSC-derived tumorigenic cells. In particular, novel approaches to directly killing tumorigenic cells by transduction of suicide genes and oncolytic viruses are expected to improve the safety of hPSC-based therapy. This article discusses the current status and future perspectives of methods aimed at directly eradicating undifferentiated tumorigenic hPSCs, with a focus on viral vector transduction.

An age-structured model to evaluate the potential of novel malaria-control interventions: a case study of fungal biopesticide sprays

PubMed Central

Hancock, P.A; Thomas, M.B; Godfray, H.C.J

2008-01-01

It has recently been proposed that mosquito vectors of human diseases, particularly malaria, may be controlled by spraying with fungal biopesticides that increase the rate of adult mortality. Though fungal pathogens do not cause instantaneous mortality, they can kill mosquitoes before they are old enough to transmit disease. A model is developed (i) to explore the potential for fungal entomopathogens to reduce significantly infectious mosquito populations, (ii) to assess the relative value of the many different fungal strains that might be used, and (iii) to help guide the tactical design of vector-control programmes. The model follows the dynamics of different classes of adult mosquitoes with the risk of mortality due to the fungus being assumed to be a function of time since infection (modelled using the Weibull distribution). It is shown that substantial reductions in mosquito numbers are feasible for realistic assumptions about mosquito, fungus and malaria biology and moderate to low daily fungal infection probability. The choice of optimal fungal strain and spraying regime is shown to depend on local mosquito and malaria biology. Fungal pathogens may also influence the ability of mosquitoes to transmit malaria and such effects are shown to further reduce vectorial capacity. PMID:18765347

Liquid-phase study of ozone inactivation of Venezuelan equine encephalomyelitis virus.

PubMed Central

Akey, D H; Walton, T E

1985-01-01

Ozone, in a liquid-phase application, was evaluated as a residue-free viral inactivant that may be suitable for use in an arboviral research laboratory. Commonly used sterilizing agents may leave trace residues, be flammable or explosive, and require lengthy periods for gases or residues to dissipate after decontamination of equipment such as biological safety cabinets. Complete liquid-phase inactivation of Venezuelan equine encephalomyelitis virus was attained at 0.025 mg of ozone per liter within 45 min of exposure. The inactivation of 10(6.5) median cell culture infective doses (CCID50 of Venezuelan equine encephalomyelitis virus per milliliter represented a reduction of 99.99997% of the viral particles from the control levels of 10(7.25-7.5) CCID50/ml. A dose-response relationship was demonstrated. Analysis by polynomial regression of the logarithmic values for both ozone concentrations and percent reduction of viral titers had a highly significant r2 of 0.8 (F = 63.6; df = 1, 16). These results, together with those of Akey (J. Econ. Entomol. 75:387-392, 1982) on the use of ozone to kill a winged arboviral vector, indicate that ozone is a promising candidate as a sterilizing agent in some applications for biological safety cabinets and other equipment used in vector studies with arboviruses. PMID:4083884

Liquid-phase study of ozone inactivation of Venezuelan equine encephalomyelitis virus.

PubMed

Akey, D H; Walton, T E

1985-10-01

Ozone, in a liquid-phase application, was evaluated as a residue-free viral inactivant that may be suitable for use in an arboviral research laboratory. Commonly used sterilizing agents may leave trace residues, be flammable or explosive, and require lengthy periods for gases or residues to dissipate after decontamination of equipment such as biological safety cabinets. Complete liquid-phase inactivation of Venezuelan equine encephalomyelitis virus was attained at 0.025 mg of ozone per liter within 45 min of exposure. The inactivation of 10(6.5) median cell culture infective doses (CCID50 of Venezuelan equine encephalomyelitis virus per milliliter represented a reduction of 99.99997% of the viral particles from the control levels of 10(7.25-7.5) CCID50/ml. A dose-response relationship was demonstrated. Analysis by polynomial regression of the logarithmic values for both ozone concentrations and percent reduction of viral titers had a highly significant r2 of 0.8 (F = 63.6; df = 1, 16). These results, together with those of Akey (J. Econ. Entomol. 75:387-392, 1982) on the use of ozone to kill a winged arboviral vector, indicate that ozone is a promising candidate as a sterilizing agent in some applications for biological safety cabinets and other equipment used in vector studies with arboviruses.

Infrared modified gravity with propagating torsion: Instability of torsionfull de Sitter-like solutions

NASA Astrophysics Data System (ADS)

Nikiforova, Vasilisa; Damour, Thibault

2018-06-01

We continue the exploration of the consistency of a modified-gravity theory that generalizes general relativity by including a dynamical torsion in addition to the dynamical metric. The six-parameter theory we consider was found to be consistent around arbitrary torsionless Einstein backgrounds, in spite of its containing a (notoriously delicate) massive spin-2 excitation. At zero bare cosmological constant, this theory was found to admit a self-accelerating solution whose exponential expansion is sustained by a nonzero torsion background. The scalar-type perturbations of the latter torsionfull self-accelerating solution were recently studied and were found to preserve the number of propagating scalar degrees of freedom, but to exhibit, for some values of the torsion background, some exponential instabilities (of a rather mild type). Here, we study the tensor-type and vector-type perturbations of the torsionfull self-accelerating solution, and of its deformation by a nonzero bare cosmological constant. We find strong, "gradient" instabilities in the vector sector. No tuning of the parameters of the theory can kill these instabilities without creating instabilities in the other sectors. Further work is needed to see whether generic torsionfull backgrounds are prone to containing gradient instabilities, or if the instabilities we found are mainly due to the (generalized) self-accelerating nature of the special de Sitter backgrounds we considered.

LAMP-1-chimeric DNA vaccines enhance the antibody response in Japanese flounder, Paralichthys olivaceus.

PubMed

Rondón-Barragán, Iang; Nozaki, Reiko; Hirono, Ikuo; Kondo, Hidehiro

2017-08-01

DNA vaccination is one method to protect farmed fish from viral and bacterial diseases. Chimeric antigens encoded by DNA vaccines have been shown to increase the resistance to viral diseases. Here, we sequenced the gene encoding lysosome-associated membrane protein-1 from Japanese flounder, Paralichthys olivaceus, (JfLAMP-1) and assessed its use in a chimeric DNA vaccine fused with the major capsule protein (MCP) from red seabream iridovirus (RSIV). JfLAMP-1 cDNA has a length of 1248 bp encoding 415 aa, which contains transmembrane and cytoplasmic domains. JfLAMP-1 is constitutively expressed in several tissues and its expression in spleen was upregulated following injection of formalin-killed cells (FKC) of Edwardsiella tarda. Immunofluorescence analysis showed that JfLAMP-1 is distributed in the small and large granules in the cytoplasm and groups close to the nucleus. The DNA encoding the luminal domain of JfLAMP-1 was replaced with the gene for the RSIV MCP, and the construct was cloned in an expression vector (pCIneo). Fish vaccinated with pCLAMP-MCP had significantly higher antibody levels than fish vaccinated with pCIneo vector harboring the MCP gene (p < 0.05) at day 30 post-vaccination. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dual stimuli polysaccharide nanovesicles for conjugated and physically loaded doxorubicin delivery in breast cancer cells.

PubMed

Pramod, P S; Shah, Ruchira; Jayakannan, Manickam

2015-04-21

The present work reports the development of pH and enzyme dual responsive polysaccharide vesicular nano-scaffolds for the administration of doxorubicin via physical loading and polymer-drug conjugation to breast cancer cells. Dextran was suitably modified with a renewable resource 3-pentadecyl phenol unit through imine and aliphatic ester chemical linkages that acted as pH and esterase enzyme stimuli, respectively. These dual responsive polysaccharide derivatives self-organized into 200 ± 10 nm diameter nano-vesicles in water. The water soluble anticancer drug doxorubicin (DOX·HCl) was encapsulated in the hydrophilic pocket to produce core-loaded polysaccharide vesicles whereas chemical conjugation produced DOX anchored at the hydrophobic layer of the dextran nano-vesicles. In vitro studies revealed that about 70-80% of the drug was retained under circulatory conditions at pH = 7.4 and 37 °C. At a low pH of 6.0 to 5.0 and in the presence of esterase; both imine and ester linkages were cleaved instantaneously to release 100% of the loaded drugs. Cytotoxicity assays on Wild Type Mouse Embryonic Fibroblasts (WTMEFs) confirmed the non-toxicity of the newly developed dextran derivatives at up to 500 μg mL(-1) in PBS. MTT assays on fibroblast cells revealed that DOX·HCl loaded nano-vesicles exhibited better killing abilities than DOX conjugated polymer nano-vesicles. Both DOX loaded and DOX conjugated nano-vesicles were found to show significant killing in breast cancer cells (MCF 7). Confocal microscopy images confirmed the uptake of DOX loaded (or conjugated) nano-vesicles by cells compared to free DOX. Thus, the newly developed pH and enzyme dual responsive polysaccharide vesicular assemblies are potential drug vectors for the administration of DOX in both loaded and chemically conjugated forms for the efficient killing of breast cancer cells.

Constructing TC-1-GLUC-LMP2 Model Tumor Cells to Evaluate the Anti-Tumor Effects of LMP2-Related Vaccines

PubMed Central

Sun, Liying; Hao, Yanzhe; Wang, Zhan; Zeng, Yi

2018-01-01

Epstein-Barr virus (EBV) is related to a variety of malignant tumors, and its encoded protein, latent membrane protein 2 (LMP2), is an effective target antigen that is widely used to construct vector vaccines. However, the model cells carrying LMP2 have still not been established to assess the oncolytic effect of LMP2-related vaccines at present. In this study, TC-1-GLUC-LMP2 tumor cells were constructed as target cells to evaluate the anti-tumor effects of LMP2-assosiated vaccines. The results showed that both LMP2 and Gaussia luciferase (GLuc) genes could be detected by polymerase chain reaction (PCR) and reverse transcription-polymerase chain reaction (RT-PCR) in TC-1-GLUC-LMP2 cells. Western blot results showed that the LMP2 and Gaussia luciferase proteins were stably expressed in tumor cells for at least 30 generations. We mixed 5 × 104 LMP2-specific mouse splenic lymphocytes with 5 × 103 TC-1-GLUC-LMP2 target cells and found that the target cells were killed as the specific killing effect was obviously enhanced by the increased quantities of LMP2-peptide stimulated spleens. Furthermore, the tumor cells could not be observed in the mice inoculated TC-1-GLUC-LMP2 cells after being immunized with vaccine-LMP2, while the vaccine-NULL immunized mice showed that tumor volume gradually grew with increased inoculation time. These results indicated that the TC-1-GLUC-LMP2 cells stably expressing LMP2 and GLuc produced tumors in mice, and that the LMP2-specific cytotoxic T lymphocyte (CTL) effectively killed the cells in vitro and in vivo, suggesting that TC-1-GLUC-LMP2 cells can be used as model cells to assess the immune and antitumor effects of LMP2-related vaccines. PMID:29570629

Imprudent fishing harvests and consequent trophic cascades on the West Florida shelf over the last half century: A harbinger of increased human deaths from paralytic shellfish poisoning along the southeastern United States, in response to oligotrophication?

NASA Astrophysics Data System (ADS)

Walsh, J. J.; Tomas, C. R.; Steidinger, K. A.; Lenes, J. M.; Chen, F. R.; Weisberg, R. H.; Zheng, L.; Landsberg, J. H.; Vargo, G. A.; Heil, C. A.

2011-06-01

Within the context of ubiquitous overfishing of piscivores, recent consequent increments of jellyfish and clupeids have occurred at the zooplanktivore trophic level in the eastern Gulf of Mexico (GOM), after overfishing of one of their predators, i.e. red snapper. Initiation of a local trophic cascade thence led to declines of herbivore stocks, documented here on the West Florida shelf. These exacerbating world-wide trophic cascades have resulted in larger harmful algal blooms (HABs), already present at the base of most coastal food webs. Impacts on human health have thus far been minimal within nutrient-rich coastal regions. To provide a setting for past morbidities, consideration is given to chronologies of other trophic cascades within eutrophic, cold water marine ecosystems of the Scotian Sea, in the Gulf of Alaska, off Southwest Africa, within the Barents, White, and Black Seas, in the Gulf of Maine, and finally in the North Sea. Next, comparison is now made here of recent ten-fold increments within Florida waters of both relatively benign and saxitoxic HABs, some of which are fatal to humans. These events are placed in a perspective of other warm shelf systems of the South China and Caribbean Seas to assess prior and possible future poison toxicities of oligotrophic coastal habitats. Past wide-spread kills of fishes and sea urchins over the Caribbean Sea and the downstream GOM are examined in relation to the potential transmission of dinoflagellate saxitoxin and other epizootic poison vectors by western boundary currents over larger "commons" than local embayments. Furthermore, since some HABs produce more potent saxitoxins upon nutrient depletion, recent decisions to ban seasonal fertilizer applications to Florida lawns may have unintended consequences. In the future, human-killing phytoplankton, rather than relatively benign fish-killing HABs of the past, may be dispersed along the southeastern United States seaboard.

Gödel universes in string theory

NASA Astrophysics Data System (ADS)

Barrow, John D.; Dabrowski, Mariusz P.

1998-11-01

We show that homogeneous Gödel spacetimes need not contain closed timelike curves in low-energy-effective string theories. We find exact solutions for the Gödel metric in string theory for the full O(α') action including both dilaton and axion fields. The results are valid for bosonic, heterotic and super-strings. To first order in the inverse string tension α', these solutions display a simple relation between the angular velocity of the Gödel universe, Ω, and the inverse string tension of the form α'=1/Ω2 in the absence of the axion field. The generalization of this relationship is also found when the axion field is present.

Classical integrable defects as quasi Bäcklund transformations

NASA Astrophysics Data System (ADS)

Doikou, Anastasia

2016-10-01

We consider the algebraic setting of classical defects in discrete and continuous integrable theories. We derive the ;equations of motion; on the defect point via the space-like and time-like description. We then exploit the structural similarity of these equations with the discrete and continuous Bäcklund transformations. And although these equations are similar they are not exactly the same to the Bäcklund transformations. We also consider specific examples of integrable models to demonstrate our construction, i.e. the Toda chain and the sine-Gordon model. The equations of the time (space) evolution of the defect (discontinuity) degrees of freedom for these models are explicitly derived.

Forward marching procedure for separated boundary-layer flows

NASA Technical Reports Server (NTRS)

Carter, J. E.; Wornom, S. F.

1975-01-01

A forward-marching procedure for separated boundary-layer flows which permits the rapid and accurate solution of flows of limited extent is presented. The streamwise convection of vorticity in the reversed flow region is neglected, and this approximation is incorporated into a previously developed (Carter, 1974) inverse boundary-layer procedure. The equations are solved by the Crank-Nicolson finite-difference scheme in which column iteration is carried out at each streamwise station. Instabilities encountered in the column iterations are removed by introducing timelike terms in the finite-difference equations. This provides both unconditional diagonal dominance and a column iterative scheme, found to be stable using the von Neumann stability analysis.

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements apply to all bridges across Newtown Creek, Dutch Kills, English Kills, and their tributaries: (1) The...

Integrability of Spinning Particle Motion in Higher-Dimensional Rotating Black Hole Spacetimes

NASA Astrophysics Data System (ADS)

Kubizňák, David; Cariglia, Marco

2012-02-01

We study the motion of a classical spinning particle (with spin degrees of freedom described by a vector of Grassmann variables) in higher-dimensional general rotating black hole spacetimes with a cosmological constant. In all dimensions n we exhibit n bosonic functionally independent integrals of spinning particle motion, corresponding to explicit and hidden symmetries generated from the principal conformal Killing-Yano tensor. Moreover, we demonstrate that in 4-, 5-, 6-, and 7-dimensional black hole spacetimes such integrals are in involution, proving the bosonic part of the motion integrable. We conjecture that the same conclusion remains valid in all higher dimensions. Our result generalizes the result of Page et al. [Phys. Rev. Lett. 98, 061102 (2007)PRLTAO0031-900710.1103/PhysRevLett.98.061102] on complete integrability of geodesic motion in these spacetimes.

Plants traditionally used as mosquito repellents and the implication for their use in vector control.

PubMed

Tisgratog, Rungarun; Sanguanpong, Unchalee; Grieco, John P; Ngoen-Kluan, Ratchadawan; Chareonviriyaphap, Theeraphap

2016-05-01

Numerous plants with insect repelling properties are native to the tropics where they are produced for a wide range of medicinal purposes. In Thailand, these native plant species have a history of use for personal protection against biting insects. From our investigation we identified 37 plant species within 14 plant families that showed some mosquito repellent properties. Of these, 9 plant species were characterized using an excito-repellency test system against several Thai mosquito species. Results from these studies revealed that five essential oils extracted from plants demonstrated promising insect repellent activity. These active ingredients show promise for further development into formulations that may serve as alternatives to DEET or possibly be used as natural bio-pesticides to kill mosquitoes. Copyright © 2016 Elsevier B.V. All rights reserved.

Isolation of Brucella pinnipedialis from Grey Seals (Halichoerus grypus) in the Baltic Sea.

PubMed

Hirvelä-Koski, Varpu; Nylund, Minna; Skrzypczak, Teresa; Heikkinen, Petra; Kauhala, Kaarina; Jay, Maryne; Isomursu, Marja

2017-10-01

Brucella infection in seals was reported for the first time in 1994 around the coast of Scotland. Since then, marine mammal Brucella infections were found to be widely distributed in the northern hemisphere. Two Brucella species affect marine mammals: Brucella pinnipedialis in pinnipeds and Brucella ceti in cetaceans. We examined the livers of Baltic grey seals (Halichoerus grypus) from the Finnish coast (n=122) hunted, found dead, or killed as by-catch in fishing gear in 2013-15 as part of population health monitoring. We detected B. pinnipedialis in the livers of three grey seals. The bacterium was isolated from livers displaying parasitic cholangitis. We also detected Brucella DNA in liver flukes (Pseudamphistomum truncatum) obtained from a Brucella-infected grey seal, suggesting that flukes might be possible vectors of this pathogen in the marine environment.

Characterization of (asymptotically) Kerr-de Sitter-like spacetimes at null infinity

NASA Astrophysics Data System (ADS)

Mars, Marc; Paetz, Tim-Torben; Senovilla, José M. M.; Simon, Walter

2016-08-01

We investigate solutions ({M},g) to Einstein's vacuum field equations with positive cosmological constant Λ which admit a smooth past null infinity {{I}}- à la Penrose and a Killing vector field whose associated Mars-Simon tensor (MST) vanishes. The main purpose of this work is to provide a characterization of these spacetimes in terms of their Cauchy data on {{I}}-. Along the way, we also study spacetimes for which the MST does not vanish. In that case there is an ambiguity in its definition which is captured by a scalar function Q. We analyze properties of the MST for different choices of Q. In doing so, we are led to a definition of ‘asymptotically Kerr-de Sitter-like spacetimes’, which we also characterize in terms of their asymptotic data on {{I}}-. Preprint UWThPh-2016-5.

Integrability conditions for Killing-Yano tensors and conformal Killing-Yano tensors

NASA Astrophysics Data System (ADS)

Batista, Carlos

2015-01-01

The integrability conditions for the existence of a conformal Killing-Yano tensor of arbitrary order are worked out in all dimensions and expressed in terms of the Weyl tensor. As a consequence, the integrability conditions for the existence of a Killing-Yano tensor are also obtained. By means of such conditions, it is shown that in certain Einstein spaces one can use a conformal Killing-Yano tensor of order p to generate a Killing-Yano tensor of order (p -1 ) . Finally, it is proved that in maximally symmetric spaces the covariant derivative of a Killing-Yano tensor is a closed conformal Killing-Yano tensor and that every conformal Killing-Yano tensor is uniquely decomposed as the sum of a Killing-Yano tensor and a closed conformal Killing-Yano tensor.

Optimizing HIV-1-specific CD8+ T-cell induction by recombinant BCG in prime-boost regimens with heterologous viral vectors.

PubMed

Hopkins, Richard; Bridgeman, Anne; Bourne, Charles; Mbewe-Mvula, Alice; Sadoff, Jerald C; Both, Gerald W; Joseph, Joan; Fulkerson, John; Hanke, Tomáš

2011-12-01

The desire to induce HIV-1-specific responses soon after birth to prevent breast milk transmission of HIV-1 led us to propose a vaccine regimen which primes HIV-1-specific T cells using a recombinant Mycobacterium bovis bacillus Calmette-Guérin (rBCG) vaccine. Because attenuated live bacterial vaccines are typically not sufficiently immunogenic as stand-alone vaccines, rBCG-primed T cells will likely require boost immunization(s). Here, we compared modified Danish (AERAS-401) and Pasteur lysine auxotroph (222) strains of BCG expressing the immunogen HIVA for their potency to prime HIV-1-specific responses in adult BALB/c mice and examined four heterologous boosting HIVA vaccines for their immunogenic synergy. We found that both BCG.HIVA(401) and BCG.HIVA(222) primed HIV-1-specific CD8(+) T-cell-mediated responses. The strongest boosts were delivered by human adenovirus-vectored HAdV5.HIVA and sheep atadenovirus-vectored OAdV7.HIVA vaccines, followed by poxvirus MVA.HIVA; the weakest was plasmid pTH.HIVA DNA. The prime-boost regimens induced T cells capable of efficient in vivo killing of sensitized target cells. We also observed that the BCG.HIVA(401) and BCG.HIVA(222) vaccines have broadly similar immunologic properties, but display a number of differences mainly detected through distinct profiles of soluble intercellular signaling molecules produced by immune splenocytes in response to both HIV-1- and BCG-specific stimuli. These results encourage further development of the rBCG prime-boost regimen. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Novel approach to abuse the hyperactive K-Ras pathway for adenoviral gene therapy of colorectal cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naumov, Inna; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv; Kazanov, Dina

2012-01-15

Background: Functional activation of oncogenic K-Ras signaling pathway plays an important role in the early events of colorectal carcinogenesis (CRC). K-Ras proto-oncogene is involved in 35-40% of CRC cases. Mutations in the Ras gene trigger the transduction of proliferative and anti-apoptotic signals, even in the absence of extra cellular stimuli. The objective of the current study was to use a gene-targeting approach to kill human CRC cells selectively harboring mutated K-Ras. Results: A recombinant adenovirus that carries a lethal gene, PUMA, under the control of a Ras responsive promoter (Ad-Py4-SV40-PUMA) was used selectively to target CRC cells (HCT116, SW480, DLD1more » and RIE-Ras) that possess a hyperactive Ras pathway while using HT29 and RIE cells as a control that harbors wild type Ras and exhibit very low Ras activity. Control vector, without the Ras responsive promoter elements was used to assess the specificity of our 'gene therapy' approach. Both adenoviral vectors were assed in vitro and in xenograft model in vivo. Ad-Py4-SV40-PUMA showed high potency to induce {approx} 50% apoptosis in vitro, to abolish completely tumor formation by infecting cells with the Ad-Py4-SV40-PUMA prior xenografting them in nude mice and high ability to suppress by {approx} 35% tumor progression in vivo in already established tumors. Conclusions: Selective targeting of CRC cells with the activated Ras pathway may be a novel and effective therapy in CRC. The high potency of this adenoviral vector may help to overcome an undetectable micro metastasis that is the major hurdle in challenging with CRC.« less

Restoration of visual response in aged dystrophic RCS rats using AAV-mediated channelopsin-2 gene transfer.

PubMed

Tomita, Hiroshi; Sugano, Eriko; Yawo, Hiromu; Ishizuka, Toru; Isago, Hitomi; Narikawa, Satoko; Kügler, Sebastian; Tamai, Makoto

2007-08-01

To investigate whether the channelopsin-2 (Chop2) gene would restore visual responses in 10-month-old dystrophic Royal College of Surgeons (aged RCS; rdy/rdy) rats, the authors transferred the Chop2 gene into the retinal cells of aged RCS rats using the adenoassociated virus (AAV) vector. The N-terminal fragment (residues 1-315) of Chop2 was fused to a fluorescent protein, Venus, in frame at the end of the Chop2 coding fragment. The viral vector construct (AAV-Chop2V) for the expression of the Chop2V in the retina was made by subcloning into an adenoassociated virus vector, including the CAG promoter. To evaluate the expression profile of Chop2V in the retina, the rats were killed and the eyes were removed and fixed with 4% paraformaldehyde in 0.1 M phosphate-buffered saline. Retinal wholemount specimens and cryosections were made. Under anesthetized conditions, electrodes for the recording of visually evoked potentials (VEPs) were implanted onto the visual cortex in aged-RCS (rdy/rdy) rats. AAV-Chop2V vectors were then injected into the vitreous cavity of the left eyes. As a control, AAV-Venus vectors were applied to the right eyes. VEPs were evoked by the flash of a blue, white, or red light-emitting diode (LED) and were recorded from the visual cortex of the rats at various time points after the AAV vector injection. Chop2V fluorescence was predominantly observed in retinal ganglion cells (RGCs). Some fluorescence was observed in the inner nuclear layer and the inner plexiform layer neurites. A tendency of recovery was observed in the VEPs of aged RCS (rdy/rdy) rats after the AAV-Chop2V injection but not after the AAV-Venus injection. The visual response of AAV-Chop2V-injected aged RCS (rdy/rdy) rats was less sensitive to the blue LED flash than that of nondystrophic RCS (+/+) rats. The AAV-Chop2V-injected aged RCS (rdy/rdy) rats were insensitive to the red LED flash, which evoked a robust VEP in the RCS (+/+) rats. The visual response of aged RCS (rdy/rdy) rats was partially restored by transduction of the Chop2 gene through AAV into the inner retinal neurons, mainly RGCs. These results suggest that the transduction of Chop2 would provide a new strategy to treat some retinitis pigmentosa (RP) symptoms independent of their etiology.

An experimental hut evaluation of Olyset Plus, a long-lasting insecticidal net treated with a mixture of permethrin and piperonyl butoxide, against Anopheles fluviatilis in Odisha State, India.

PubMed

Gunasekaran, Kasinathan; Sahu, Sudhansu Sekhar; Vijayakumar, Tharmalingam; Subramanian, Swaminathan; Yadav, Rajpal Singh; Pigeon, Olivier; Jambulingam, Purushothaman

2016-07-21

Fast development of pyrethroid resistance in malaria vectors prompted the development of new vector control tools including combination of insecticides with different modes of action as part of resistance management strategies. Olyset Plus® is a new long-lasting insecticidal net, in which, permethrin and a synergist, piperonyl butoxide (PBO), are incorporated into filaments. Mixture nets such as this may have application against resistant mosquitoes, particularly those whose resistance is based on oxidative metabolism. There may also be enhanced activity against susceptible mosquitoes since mixed function oxidases are involved in a many metabolic activities including activation to form bioactive compounds. Bio-efficacy of Olyset Plus was evaluated against susceptible malaria vector, Anopheles fluviatilis in experimental huts. Deterrence, blood feeding inhibition, induced exophily and killing effect were measured to assess the bio-efficacy. The results were compared with Olyset Net®, a polyethylene permethrin-incorporated LLIN and a conventionally treated polyester net (with permethrin) washed to just before exhaustion. Results showed significant reduction in entry (treatment: 0.4-0.8; control: 4.2 per trap-night) and increase in exit (56.3-82.9 % and 44.2 %) rates of Anopheles fluviatilis in the treatment arms compared to control (P < 0.05). While blood feeding rates declined in treatment arms (18.8-30.6 %), it increased in control (77.6 %) (P < 0.05). This was further evident from the blood-feeding inhibition rates in treatment arms (60.6-90.6 %). Total mortality was significantly higher in all treatment arms (96.3-100 %) compared to control arm (2 %) (P < 0.05). Chemical analysis for active ingredient (AI) showed retention of 75 and 88 % in Olyset plus and Olyset net respectively after 20 washes. Performance of Olyset Plus washed 20 times was equal to the CTN and Olyset Net against the susceptible malaria vector An. fluviatilis, fulfilling the WHO efficacy criteria of Phase II evaluation for LLIN. However, the benefit of incorporating PBO and permethrin together in a long-lasting treatment could not be demonstrated in the current study as the target vector species was fully susceptible to pyrethroids. Olyset Plus, with its intrinsic bio-efficacy could be an effective vector control tool to prevent transmission of malaria by susceptible vectors like An. fluviatilis. However, the results of the current study need to be further supported by testing the net at village level (Phase III) for community acceptability. Before taking the net to village level, it needs to be verified whether the net is better than pyrethroid nets in terms of bio-efficacy against resistant An. culicifacies, another malaria vector that has developed resistance to synthetic pyrethroids in India.

Spiroplasma infection causes either early or late male killing in Drosophila, depending on maternal host age

NASA Astrophysics Data System (ADS)

Kageyama, Daisuke; Anbutsu, Hisashi; Shimada, Masakazu; Fukatsu, Takema

2007-04-01

Symbiont-induced male-killing phenotypes have been found in a variety of insects. Conventionally, these phenotypes have been divided into two categories according to the timing of action: early male killing at embryonic stages and late male killing at late larval stages. In Drosophila species, endosymbiotic bacteria of the genus Spiroplasma have been known to cause early male killing. Here, we report that a spiroplasma strain normally causing early male killing also induces late male killing depending on the maternal host age: male-specific mortality of larvae and pupae was more frequently observed in the offspring of young females. As the lowest spiroplasma density and occasional male production were also associated with newly emerged females, we proposed the density-dependent hypothesis for the expression of early and late male-killing phenotypes. Our finding suggested that (1) early and late male-killing phenotypes can be caused by the same symbiont and probably by the same mechanism; (2) late male killing may occur as an attenuated expression of early male killing; (3) expression of early and late male-killing phenotypes may be dependent on the symbiont density, and thus, could potentially be affected by the host immunity and regulation; and (4) early male killing and late male killing could be alternative strategies adopted by microbial reproductive manipulators.

Colonization of Rhodnius prolixus gut by Trypanosoma cruzi involves an extensive parasite killing.

PubMed

Ferreira, Roberta Carvalho; Kessler, Rafael Luis; Lorenzo, Marcelo Gustavo; Paim, Rafaela Magalhães Macedo; Ferreira, Luciana De Lima; Probst, Christian Macagnan; Alves-Silva, Juliana; Guarneri, Alessandra Aparecida

2016-04-01

Trypanosoma cruzi, the etiological agent of Chagas disease, is ingested by triatomines during their bloodmeal on an infected mammal. Aiming to investigate the development and differentiation of T. cruzi inside the intestinal tract of Rhodnius prolixus at the beginning of infection we fed insects with cultured epimastigotes and blood trypomastigotes from infected mice to determine the amount of recovered parasites after ingestion. Approximately 20% of the ingested parasites was found in the insect anterior midgut (AM) 3 h after feeding. Interestingly, a significant reduction (80%) in the numbers of trypomastigotes was observed after 24 h of infection suggesting that parasites were killed in the AM. Moreover, few parasites were found in that intestinal portion after 96 h of infection. The evaluation of the numbers of parasites in the posterior midgut (PM) at the same periods showed a reduced parasite load, indicating that parasites were not moving from the AM. Additionally, incubation of blood trypomastigotes with extracts from R. prolixus AMs revealed that components of this tissue could induce significant death of T. cruzi. Finally, we observed that differentiation from trypomastigotes to epimastigotes is not completed in the AM; instead we suggest that trypomastigotes change to intermediary forms before their migration to the PM, where differentiation to epimastigotes takes place. The present work clarifies controversial points concerning T. cruzi development in insect vector, showing that parasite suffers a drastic decrease in population size before epimastigonesis accomplishment in PM.

Enhanced EJ Cell Killing of (125)I Radiation by Combining with Cytosine Deaminase Gene Therapy Regulated by Synthetic Radio-Responsive Promoter.

PubMed

Li, Ling; Zhang, Chun-li; Kang, Lei; Wang, Rong-Fu; Yan, Ping; Zhao, Qian; Yin, Lei; Guo, Feng-qin

2015-10-01

To investigate the enhancing effect of radionuclide therapy by the therapeutic gene placed under the control of radio-responsive promoter. The recombinant lentivirus E8-codA-GFP, including a synthetic radiation-sensitive promoter E8, cytosine deaminase (CD) gene, and green fluorescent protein gene, was constructed. The gene expression activated by (125)I radiation was assessed by observation of green fluorescence. The ability of converting 5-fluorocytosine (5-FC) to 5-fluorourial (5-FU) by CD enzyme was assessed by high-performance liquid chromatography. The viability of the infected cells exposed to (125)I in the presence of 5-FC was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the infected cells exposed to (125)I alone served as negative control and 5-FU as positive control. The recombinant lentiviral vector was constructed successfully. On exposure of infected cells to (125)I, green fluorescence can be observed and 5-FU can be detected. MTT assay showed that the survival rate for infected cells treated with (125)I was lower compared with the (125)I control group, but higher than the positive control group. The synthetic promoter E8 can induce the expression of downstream CD gene under (125)I radiation, and the tumor killing effect of (125)I can be enhanced by combining CD gene therapy with radiosensitive promoter.

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements...

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements...

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements...

33 CFR 117.801 - Newtown Creek, Dutch Kills, English Kills and their tributaries.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Newtown Creek, Dutch Kills, English Kills and their tributaries. 117.801 Section 117.801 Navigation and Navigable Waters COAST GUARD....801 Newtown Creek, Dutch Kills, English Kills and their tributaries. (a) The following requirements...

Evidence for Personal Protective Measures to Reduce Human Contact With Blacklegged Ticks and for Environmentally Based Control Methods to Suppress Host-Seeking Blacklegged Ticks and Reduce Infection with Lyme Disease Spirochetes in Tick Vectors and Rodent Reservoirs.

PubMed

Eisen, Lars; Dolan, Marc C

2016-07-20

In the 1980s, the blacklegged tick, Ixodes scapularis Say, and rodents were recognized as the principal vector and reservoir hosts of the Lyme disease spirochete Borrelia burgdorferi in the eastern United States, and deer were incriminated as principal hosts for I. scapularis adults. These realizations led to pioneering studies aiming to reduce the risk for transmission of B. burgdorferi to humans by attacking host-seeking ticks with acaricides, interrupting the enzootic transmission cycle by killing immatures infesting rodent reservoirs by means of acaricide-treated nesting material, or reducing deer abundance to suppress tick numbers. We review the progress over the past three decades in the fields of: 1) prevention of human-tick contact with repellents and permethrin-treated clothing, and 2) suppression of I. scapularis and disruption of enzootic B. burgdorferi transmission with environmentally based control methods. Personal protective measures include synthetic and natural product-based repellents that can be applied to skin and clothing, permethrin sprays for clothing and gear, and permethrin-treated clothing. A wide variety of approaches and products to suppress I. scapularis or disrupt enzootic B. burgdorferi transmission have emerged and been evaluated in field trials. Application of synthetic chemical acaricides is a robust method to suppress host-seeking I. scapularis ticks within a treated area for at least 6-8 wk. Natural product-based acaricides or entomopathogenic fungi have emerged as alternatives to kill host-seeking ticks for homeowners who are unwilling to use synthetic chemical acaricides. However, as compared with synthetic chemical acaricides, these approaches appear less robust in terms of both their killing efficacy and persistence. Use of rodent-targeted topical acaricides represents an alternative for homeowners opposed to open distribution of acaricides to the ground and vegetation on their properties. This host-targeted approach also provides the benefit of the intervention impacting the entire rodent home range. Rodent-targeted oral vaccines against B. burgdorferi and a rodent-targeted antibiotic bait have been evaluated in laboratory and field trials but are not yet commercially available. Targeting of deer-via deer reduction or treatment of deer with topical acaricides-can provide area-wide suppression of host-seeking I. scapularis These two deer-targeted approaches combine great potential for protection that impacts the entire landscape with severe problems relating to public acceptance or implementation logistics. Integrated use of two or more methods has unfortunately been evaluated in very few published studies, but additional field evaluations of integrated tick and pathogen strategies are underway. Published by Oxford University Press on behalf of Journal of Medical Entomology 2016. This work is written by US Government employees and is in the public domain in the US.

Winding solutions for the two-particle system in ? gravity

NASA Astrophysics Data System (ADS)

Welling, M.

1998-03-01

We use a computer to follow the evolution of two gravitating particles in a (2 + 1)-dimensional closed universe. In a closed universe there is enough energy to produce a Gott-pair, i.e. a pair of particles with tachyonic centre of mass, from regular initial data. We study such a pair and find that they can wind around each other with ever increasing momentum. As was shown by 't Hooft, the universe must crunch before any closed timelike curve can be traversed. We study the two-particle system and quantize it, long before this crunch happens, in the high-momentum limit. We find that both the relevant configuration variable and its conjugate momentum become discretized.

N-point functions in rolling tachyon background

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jokela, Niko; Keski-Vakkuri, Esko; Department of Physics, P.O. Box 64, FIN-00014, University of Helsinki

2009-04-15

We study n-point boundary correlation functions in timelike boundary Liouville theory, relevant for open string multiproduction by a decaying unstable D brane. We give an exact result for the one-point function of the tachyon vertex operator and show that it is consistent with a previously proposed relation to a conserved charge in string theory. We also discuss when the one-point amplitude vanishes. Using a straightforward perturbative expansion, we find an explicit expression for a tachyon n-point amplitude for all n, however the result is still a toy model. The calculation uses a new asymptotic approximation for Toeplitz determinants, derived bymore » relating the system to a Dyson gas at finite temperature.« less

Dispersive analysis of the pion transition form factor

NASA Astrophysics Data System (ADS)

Hoferichter, M.; Kubis, B.; Leupold, S.; Niecknig, F.; Schneider, S. P.

2014-11-01

We analyze the pion transition form factor using dispersion theory. We calculate the singly-virtual form factor in the time-like region based on data for the cross section, generalizing previous studies on decays and scattering, and verify our result by comparing to data. We perform the analytic continuation to the space-like region, predicting the poorly-constrained space-like transition form factor below , and extract the slope of the form factor at vanishing momentum transfer . We derive the dispersive formalism necessary for the extension of these results to the doubly-virtual case, as required for the pion-pole contribution to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.

Black hole solutions in mimetic Born-Infeld gravity

NASA Astrophysics Data System (ADS)

Chen, Che-Yu; Bouhmadi-López, Mariam; Chen, Pisin

2018-01-01

The vacuum, static, and spherically symmetric solutions in the mimetic Born-Infeld gravity are studied. The mimetic Born-Infeld gravity is a reformulation of the Eddington-inspired-Born-Infeld (EiBI) model under the mimetic approach. Due to the mimetic field, the theory contains non-trivial vacuum solutions different from those in Einstein gravity. We find that with the existence of the mimetic field, the spacelike singularity inside a Schwarzschild black hole could be altered to a lightlike singularity, even though the curvature invariants still diverge at the singularity. Furthermore, in this case, the maximal proper time for a timelike radially-infalling observer to reach the singularity is found to be infinite.

Inverse Problems for Semilinear Wave Equations on Lorentzian Manifolds

NASA Astrophysics Data System (ADS)

Lassas, Matti; Uhlmann, Gunther; Wang, Yiran

2018-06-01

We consider inverse problems in space-time ( M, g), a 4-dimensional Lorentzian manifold. For semilinear wave equations {\\square_g u + H(x, u) = f}, where {\\square_g} denotes the usual Laplace-Beltrami operator, we prove that the source-to-solution map {L: f → u|_V}, where V is a neighborhood of a time-like geodesic {μ}, determines the topological, differentiable structure and the conformal class of the metric of the space-time in the maximal set, where waves can propagate from {μ} and return back. Moreover, on a given space-time ( M, g), the source-to-solution map determines some coefficients of the Taylor expansion of H in u.

Black hole solutions in mimetic Born-Infeld gravity.

PubMed

Chen, Che-Yu; Bouhmadi-López, Mariam; Chen, Pisin

2018-01-01

The vacuum, static, and spherically symmetric solutions in the mimetic Born-Infeld gravity are studied. The mimetic Born-Infeld gravity is a reformulation of the Eddington-inspired-Born-Infeld (EiBI) model under the mimetic approach. Due to the mimetic field, the theory contains non-trivial vacuum solutions different from those in Einstein gravity. We find that with the existence of the mimetic field, the spacelike singularity inside a Schwarzschild black hole could be altered to a lightlike singularity, even though the curvature invariants still diverge at the singularity. Furthermore, in this case, the maximal proper time for a timelike radially-infalling observer to reach the singularity is found to be infinite.

Black hole solutions in mimetic Born-Infeld gravity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Che-Yu; Bouhmadi-López, Mariam; Chen, Pisin

The vacuum, static, and spherically symmetric solutions in the mimetic Born-Infeld gravity are studied. The mimetic Born-Infeld gravity is a reformulation of the Eddington-inspired-Born-Infeld (EiBI) model under the mimetic approach. Due to the mimetic field, the theory contains non-trivial vacuum solutions different from those in Einstein gravity. Here, we find that with the existence of the mimetic field, the spacelike singularity inside a Schwarzschild black hole could be altered to a lightlike singularity, even though the curvature invariants still diverge at the singularity. Furthermore, in this case, the maximal proper time for a timelike radially-infalling observer to reach the singularitymore » is found to be infinite.« less

Black hole solutions in mimetic Born-Infeld gravity

DOE PAGES

Chen, Che-Yu; Bouhmadi-López, Mariam; Chen, Pisin

2018-01-23

The vacuum, static, and spherically symmetric solutions in the mimetic Born-Infeld gravity are studied. The mimetic Born-Infeld gravity is a reformulation of the Eddington-inspired-Born-Infeld (EiBI) model under the mimetic approach. Due to the mimetic field, the theory contains non-trivial vacuum solutions different from those in Einstein gravity. Here, we find that with the existence of the mimetic field, the spacelike singularity inside a Schwarzschild black hole could be altered to a lightlike singularity, even though the curvature invariants still diverge at the singularity. Furthermore, in this case, the maximal proper time for a timelike radially-infalling observer to reach the singularitymore » is found to be infinite.« less

Horizon fluffs: In the context of generalized minimal massive gravity

NASA Astrophysics Data System (ADS)

Setare, Mohammad Reza; Adami, Hamed

2018-02-01

We consider a metric which describes Bañados geometries and show that the considered metric is a solution of the generalized minimal massive gravity (GMMG) model. We consider the Killing vector field which preserves the form of the considered metric. Using the off-shell quasi-local approach we obtain the asymptotic conserved charges of the given solution. Similar to the Einstein gravity in the presence of negative cosmological constant, for the GMMG model, we also show that the algebra among the asymptotic conserved charges is isomorphic to two copies of the Virasoro algebra. Eventually, we find a relation between the algebra of the near-horizon and the asymptotic conserved charges. This relation shows that the main part of the horizon fluffs proposed by Afshar et al., Sheikh-Jabbari and Yavartanoo appear for generic black holes in the class of Bañados geometries in the context of the GMMG model.

Interrelationships of food safety and plant pathology: the life cycle of human pathogens on plants.

PubMed

Barak, Jeri D; Schroeder, Brenda K

2012-01-01

Bacterial food-borne pathogens use plants as vectors between animal hosts, all the while following the life cycle script of plant-associated bacteria. Similar to phytobacteria, Salmonella, pathogenic Escherichia coli, and cross-domain pathogens have a foothold in agricultural production areas. The commonality of environmental contamination translates to contact with plants. Because of the chronic absence of kill steps against human pathogens for fresh produce, arrival on plants leads to persistence and the risk of human illness. Significant research progress is revealing mechanisms used by human pathogens to colonize plants and important biological interactions between and among bacteria in planta. These findings articulate the difficulty of eliminating or reducing the pathogen from plants. The plant itself may be an untapped key to clean produce. This review highlights the life of human pathogens outside an animal host, focusing on the role of plants, and illustrates areas that are ripe for future investigation.

Urban parasitology: visceral leishmaniasis in Brazil.

PubMed

Harhay, Michael O; Olliaro, Piero L; Costa, Dorcas Lamounier; Costa, Carlos Henrique Nery

2011-09-01

Since the early 1980s, visceral leishmaniasis (VL) which is, in general, a rural zoonotic disease, has spread to the urban centers of the north, and now the south and west of Brazil. The principal drivers differ between cities, though human migration, large urban canid populations (animal reservoir), and a decidedly peripatetic and adaptable sand fly vector are the primary forces. The exact number of urban cases remains unclear as a result of challenges with surveillance. However, the number of urban cases registered continues to increase annually. Most control initiatives (e.g. culling infected dogs and household spraying to kill the sand fly) could be effective, but have proven hard to maintain at large scales due to logistical, financial and other reasons. In this article, the urbanization of VL in Brazil is reviewed, touching on these and other topics related to controlling VL within and outside Brazil. Copyright © 2011 Elsevier Ltd. All rights reserved.

Spatial Analysis of West Nile Virus: Predictive Risk Modeling of a Vector-borne Infectious Disease in Illinois by Means of NASA Earth Observation Systems

NASA Technical Reports Server (NTRS)

Renneboog, Nathan; Gathings, David; Hemmings, Sarah; Makasa, Emmanuel; Omer, Wigdan; Tipre, Meghan; Wright, Catherine; McAllister, Marilyn; Luvall, Jeffrey C.

2009-01-01

West Nile Virus is a mosquito-borne virus of the family Flaviviridae. It infects birds and various mammals, including humans, and can cause encephalitis that may prove fatal, notably among vulnerable populations. Since its identification in New York City in 1999, WNV has become established in a broad range of ecological settings throughout North America, infecting more than 25,300 people and killing 1133 as of 2008 (CDC,2009). WNV is transmitted by mosquitoes that feed on infected birds. As a result, the degree of human infection depends on local ecology and human exposure. This study hypothesizes that remote sensing and GIS can be used to analyze environmental determinants of WNV transmission, such as climate, elevation, land cover, and vegetation densities, to map areas of WNV risk for surveillance and intervention.

Synthesis and insecticidal activity of acridone derivatives to Aedes aegypti and Culex quinquefasciatus larvae and non-target aquatic species

NASA Astrophysics Data System (ADS)

Roopan, Selvaraj Mohana; Bharathi, Annadurai; Al-Dhabi, Naif Abdullah; Arasu, Mariadhas Valan; Madhumitha, G.

2017-01-01

A serious Mosquito borne yellow fever is one of the grave diseases which affect the major population. Since there is no specific treatment for yellow fever, there is a necessity to develop an effective agent. The series of acridinone analogues 3 to 5 were synthesized with help of non-conventional microwave heating and confirmed by respective spectral characterization. 5c and 3b showed highest activity to kill 90% of larvae against A. aegypti and C. quinquefasciatus, respectively. Also the active products were treated to check the mortality of non-target aquatic species. Through the reports of the larvicidal bioassay, compounds 3b against C. quinquefasciatus whereas 5c against A. aegypti were found to be more active. By keeping this as a platform, further extension of the work can be done to find out a valuable drug for controlling disease vectors.

Static axisymmetric Einstein equations in vacuum: Symmetry, new solutions, and Ricci solitons

NASA Astrophysics Data System (ADS)

Akbar, M. M.; MacCallum, M. A. H.

2015-09-01

An explicit one-parameter Lie point symmetry of the four-dimensional vacuum Einstein equations with two commuting hypersurface-orthogonal Killing vector fields is presented. The parameter takes values over all of the real line and the action of the group can be effected algebraically on any solution of the system. This enables one to construct particular one-parameter extended families of axisymmetric static solutions and cylindrical gravitational wave solutions from old ones, in a simpler way than most solution-generation techniques, including the prescription given by Ernst for this system. As examples, we obtain the families that generalize the Schwarzschild solution and the C -metric. These in effect superpose a Levi-Civita cylindrical solution on the seeds. Exploiting a correspondence between static solutions of Einstein's equations and Ricci solitons (self-similar solutions of the Ricci flow), this also enables us to construct new steady Ricci solitons.

Microgravity as a novel environmental signal affecting Salmonella enterica serovar Typhimurium virulence

NASA Technical Reports Server (NTRS)

Nickerson, C. A.; Ott, C. M.; Mister, S. J.; Morrow, B. J.; Burns-Keliher, L.; Pierson, D. L.

2000-01-01

The effects of spaceflight on the infectious disease process have only been studied at the level of the host immune response and indicate a blunting of the immune mechanism in humans and animals. Accordingly, it is necessary to assess potential changes in microbial virulence associated with spaceflight which may impact the probability of in-flight infectious disease. In this study, we investigated the effect of altered gravitational vectors on Salmonella virulence in mice. Salmonella enterica serovar Typhimurium grown under modeled microgravity (MMG) were more virulent and were recovered in higher numbers from the murine spleen and liver following oral infection compared to organisms grown under normal gravity. Furthermore, MMG-grown salmonellae were more resistant to acid stress and macrophage killing and exhibited significant differences in protein synthesis than did normal-gravity-grown cells. Our results indicate that the environment created by simulated microgravity represents a novel environmental regulatory factor of Salmonella virulence.

The Case for a Smoker's License

PubMed Central

Chapman, Simon

2012-01-01

Background to the debate Tobacco continues to kill millions of people around the world each year and its use is increasing in some countries, which makes the need for new, creative, and radical efforts to achieve the tobacco control endgame vitally important. One such effort is discussed in this PLOS Medicine Debate, where Simon Chapman presents his proposal for a “smoker's license” and Jeff Collin argues against. Chapman sets out a case for introducing a smart card license for smokers designed to limit access to tobacco products and encourage cessation. Key elements of the smoker's license include smokers setting daily limits, financial incentives for permanent license surrender, and a test of health risk knowledge for commencing smokers. Collin argues against the proposal, saying that it would shift focus away from the real vector of the epidemic—the tobacco industry—and that by focusing on individuals it would censure victims, increase stigmatization of smokers, and marginalize the poor. PMID:23152726

Geometrothermodynamics for black holes and de Sitter space

NASA Astrophysics Data System (ADS)

Kurihara, Yoshimasa

2018-02-01

A general method to extract thermodynamic quantities from solutions of the Einstein equation is developed. In 1994, Wald established that the entropy of a black hole could be identified as a Noether charge associated with a Killing vector of a global space-time (pseudo-Riemann) manifold. We reconstruct Wald's method using geometrical language, e.g., via differential forms defined on the local space-time (Minkowski) manifold. Concurrently, the abstract thermodynamics are also reconstructed using geometrical terminology, which is parallel to general relativity. The correspondence between the thermodynamics and general relativity can be seen clearly by comparing the two expressions. This comparison requires a modification of Wald's method. The new method is applied to Schwarzschild, Kerr, and Kerr-Newman black holes and de Sitter space. The results are consistent with previous results obtained using various independent methods. This strongly supports the validity of the area theorem for black holes.

Conformal superalgebras via tractor calculus

NASA Astrophysics Data System (ADS)

Lischewski, Andree

2015-01-01

We use the manifestly conformally invariant description of a Lorentzian conformal structure in terms of a parabolic Cartan geometry in order to introduce a superalgebra structure on the space of twistor spinors and normal conformal vector fields formulated in purely algebraic terms on parallel sections in tractor bundles. Via a fixed metric in the conformal class, one reproduces a conformal superalgebra structure that has been considered in the literature before. The tractor approach, however, makes clear that the failure of this object to be a Lie superalgebra in certain cases is due to purely algebraic identities on the spinor module and to special properties of the conformal holonomy representation. Moreover, it naturally generalizes to higher signatures. This yields new formulas for constructing new twistor spinors and higher order normal conformal Killing forms out of existing ones, generalizing the well-known spinorial Lie derivative. Moreover, we derive restrictions on the possible dimension of the space of twistor spinors in any metric signature.

First report of a naturally patent infection with Dirofilaria immitis in an otter (Lutra lutra).

PubMed

Penezić, Aleksandra; Moriano, Roberta; Spasić, Marija; Ćirović, Duško

2018-03-01

Dirofilaria immitis causes a severe and life-threatening cardio-pulmonary disease in Europe, Asia, Africa, and the Americas; also, zoonotic infections have been reported. This parasitic vector-borne disease is mostly common in domestic and wild canids and felids. Here, we present a rare finding of this roundworm in the heart of a Eurasian otter (Lutra lutra). Four mature specimens of D. immitis were found in the right ventricle of the heart. Necropsy was performed after the animal was found road-killed in Eastern Serbia, close to the Danube River. Two heartworms were females, one was male and sex for one remained unidentified. Microfilariae were present in the uterus of one of the female heartworms, indicating that otters can act as reservoirs of dirofilariasis in the wild. This is the first report of a patent infection in a free-ranging otter.

The Sri Lanka tsunami experience.

PubMed

Yamada, Seiji; Gunatilake, Ravindu P; Roytman, Timur M; Gunatilake, Sarath; Fernando, Thushara; Fernando, Lalan

2006-01-01

The Indian Ocean tsunami of 2004 killed 31,000 people in Sri Lanka and produced morbidity primarily resulting from near-drownings and traumatic injuries. In the immediate aftermath, the survivors brought bodies to the hospitals, which hampered the hospitals' operations. The fear of epidemics led to mass burials. Infectious diseases were prevented through the provision of clean water and through vector control. Months after the tsunami, little rebuilding of permanent housing was evident, and many tsunami victims continued to reside in transit camps without means of generating their own income. The lack of an incident command system, limited funding, and political conflicts were identified as barriers to optimal relief efforts. Despite these barriers, Sri Lanka was fortunate in drawing upon a well-developed community health infrastructure as well as local and international resources. The need continues for education and training in clinical skills for mass rescue and emergency treatment, as well as participation in a multidisciplinary response.

Co-breeding Association of Aedes albopictus (Skuse) and Aedes aegypti (Linnaeus) (Diptera: Culicidae) in Relation to Location and Container Size

PubMed Central

Hashim, Nur Aida; Ahmad, Abu Hassan; Talib, Anita; Athaillah, Farida; Krishnan, Kumara Thevan

2018-01-01

The occurrence of major outbreaks of dengue, and other vector borne diseases such as chikungunya and zika in tropical and subtropical regions has rendered control of the diseases a top-priority for many affected countries including Malaysia. Control of the mosquito vectors Aedes aegypti and Aedes albopictus through the reduction of breeding sites and the application of insecticides to kill immature forms and adults are the main control efforts to combat these diseases. The present study describes the association between Ae. albopictus and Ae. aegypti in shared breeding sites. This study is important given that any measure taken against one species may affect the other. A yearlong larval survey was conducted in four dengue endemic areas of Penang Island. Sorenson’s coefficient index indicated that no association between number of the immatures of the two species regardless of container size and study location. Therefore, the mean number Ae. albopictus immature was not decreased in the presence of Ae. aegypti in shared breeding container. However Ae. aegypti appeared to prefer breeding in habitats not occupied by Ae. albopictus, the two species sharing breeding sites only where available containers were limited. In control efforts, eliminating the preferred breeding containers for one species might not affect or reduce the population of the other species. PMID:29644025

Novel adjuvants & delivery vehicles for vaccines development: a road ahead.

PubMed

Mohan, Teena; Verma, Priyanka; Rao, D Nageswara

2013-11-01

The pure recombinant and synthetic antigens used in modern day vaccines are generally less immunogenic than older style live/attenuated and killed whole organism vaccines. One can improve the quality of vaccine production by incorporating immunomodulators or adjuvants with modified delivery vehicles viz. liposomes, immune stimulating complexes (ISCOMs), micro/nanospheres apart from alum, being used as gold standard. Adjuvants are used to augment the effect of a vaccine by stimulating the immune system to respond to the vaccine, more vigorously, and thus providing increased immunity to a particular disease. Adjuvants accomplish this task by mimicking specific sets of evolutionary conserved molecules which include lipopolysaccharides (LPS), components of bacterial cell wall, endocytosed nucleic acids such as dsRNA, ssDNA and unmethylated CpG dinucleotide containing DNA. This review provides information on various vaccine adjuvants and delivery vehicles being developed to date. From literature, it seems that the humoral immune responses have been observed for most adjuvants and delivery platforms while viral-vector, ISCOMs and Montanides have shown cytotoxic T-cell response in the clinical trials. MF59 and MPL® have elicited Th1 responses, and virus-like particles (VLPs), non-degradable nanoparticle and liposomes have also generated cellular immunity. Such vaccine components have also been evaluated for alternative routes of administration with clinical success reported for intranasal delivery of viral-vectors and proteosomes and oral delivery of VLP vaccines.

Novel adjuvants & delivery vehicles for vaccines development: A road ahead

PubMed Central

Mohan, Teena; Verma, Priyanka; Rao, D. Nageswara

2013-01-01

The pure recombinant and synthetic antigens used in modern day vaccines are generally less immunogenic than older style live/attenuated and killed whole organism vaccines. One can improve the quality of vaccine production by incorporating immunomodulators or adjuvants with modified delivery vehicles viz. liposomes, immune stimulating complexes (ISCOMs), micro/nanospheres apart from alum, being used as gold standard. Adjuvants are used to augment the effect of a vaccine by stimulating the immune system to respond to the vaccine, more vigorously, and thus providing increased immunity to a particular disease. Adjuvants accomplish this task by mimicking specific sets of evolutionary conserved molecules which include lipopolysaccharides (LPS), components of bacterial cell wall, endocytosed nucleic acids such as dsRNA, ssDNA and unmethylated CpG dinucleotide containing DNA. This review provides information on various vaccine adjuvants and delivery vehicles being developed to date. From literature, it seems that the humoral immune responses have been observed for most adjuvants and delivery platforms while viral-vector, ISCOMs and Montanides have shown cytotoxic T-cell response in the clinical trials. MF59 and MPL® have elicited Th1 responses, and virus-like particles (VLPs), non-degradable nanoparticle and liposomes have also generated cellular immunity. Such vaccine components have also been evaluated for alternative routes of administration with clinical success reported for intranasal delivery of viral-vectors and proteosomes and oral delivery of VLP vaccines. PMID:24434331

Victims and vectors: highly pathogenic avian influenza H5N1 and the ecology of wild birds

USGS Publications Warehouse

Takekawa, John Y.; Prosser, Diann J.; Newman, Scott H.; Muzaffar, Sabir Bin; Hill, Nichola J.; Yan, Baoping; Xiao, Xiangming; Lei, Fumin; Li, Tianxian; Schwarzbach, Steven E.; Howell, Judd A.

2010-01-01

The emergence of highly pathogenic avian influenza (HPAI) viruses has raised concerns about the role of wild birds in the spread and persistence of the disease. In 2005, an outbreak of the highly pathogenic subtype H5N1 killed more than 6,000 wild waterbirds at Qinghai Lake, China. Outbreaks have continued to periodically occur in wild birds at Qinghai Lake and elsewhere in Central China and Mongolia. This region has few poultry but is a major migration and breeding area for waterbirds in the Central Asian Flyway, although relatively little is known about migratory movements of different species and connectivity of their wetland habitats. The scientific debate has focused on the role of waterbirds in the epidemiology, maintenance and spread of HPAI H5N1: to what extent are they victims affected by the disease, or vectors that have a role in disease transmission? In this review, we summarise the current knowledge of wild bird involvement in the ecology of HPAI H5N1. Specifically, we present details on: (1) origin of HPAI H5N1; (2) waterbirds as LPAI reservoirs and evolution into HPAI; (3) the role of waterbirds in virus spread and persistence; (4) key biogeographic regions of outbreak; and (5) applying an ecological research perspective to studying AIVs in wild waterbirds and their ecosystems.

Partial complementation of the UV sensitivity of E. coli and yeast excision repair mutants by the cloned denV gene of bacteriophage T4.

PubMed

Chenevert, J M; Naumovski, L; Schultz, R A; Friedberg, E C

1986-04-01

The denV gene of bacteriophage T4 was reconstituted from two overlapping DNA fragments cloned in M13 vectors. The coding region of the intact gene was tailored into a series of plasmid vectors containing different promoters suitable for expression of the gene in E. coli and in yeast. Induction of the TAC promoter with IPTG resulted in overexpression of the gene, which was lethal to E. coli. Expression of the TACdenV gene in the absence of IPTG, or the use of the yeast GAL1 or ADH promoters resulted in partial complementation of the UV sensitivity of uvrA, uvrB, uvrC and recA mutants of E. coli and rad1, rad2, rad3, rad4 and rad10 mutants of S. cerevisiae. The extent of denV-mediated reactivation of excision-defective mutants was approximately equal to that of photoreactivation of such strains. Excision proficient E. coli cells transformed with a plasmid containing the denV gene were slightly more resistant to ultraviolet (UV) radiation than control cells without the denV gene. On the other hand, excision proficient yeast cells were slightly more sensitive to killing by UV radiation following transformation with a plasmid containing the denV gene. This effect was more pronounced in yeast mutants of the RAD52 epistasis group.

Dual stimuli polysaccharide nanovesicles for conjugated and physically loaded doxorubicin delivery in breast cancer cells

NASA Astrophysics Data System (ADS)

Pramod, P. S.; Shah, Ruchira; Jayakannan, Manickam

2015-04-01

The present work reports the development of pH and enzyme dual responsive polysaccharide vesicular nano-scaffolds for the administration of doxorubicin via physical loading and polymer-drug conjugation to breast cancer cells. Dextran was suitably modified with a renewable resource 3-pentadecyl phenol unit through imine and aliphatic ester chemical linkages that acted as pH and esterase enzyme stimuli, respectively. These dual responsive polysaccharide derivatives self-organized into 200 +/- 10 nm diameter nano-vesicles in water. The water soluble anticancer drug doxorubicin (DOX.HCl) was encapsulated in the hydrophilic pocket to produce core-loaded polysaccharide vesicles whereas chemical conjugation produced DOX anchored at the hydrophobic layer of the dextran nano-vesicles. In vitro studies revealed that about 70-80% of the drug was retained under circulatory conditions at pH = 7.4 and 37 °C. At a low pH of 6.0 to 5.0 and in the presence of esterase; both imine and ester linkages were cleaved instantaneously to release 100% of the loaded drugs. Cytotoxicity assays on Wild Type Mouse Embryonic Fibroblasts (WTMEFs) confirmed the non-toxicity of the newly developed dextran derivatives at up to 500 μg mL-1 in PBS. MTT assays on fibroblast cells revealed that DOX.HCl loaded nano-vesicles exhibited better killing abilities than DOX conjugated polymer nano-vesicles. Both DOX loaded and DOX conjugated nano-vesicles were found to show significant killing in breast cancer cells (MCF 7). Confocal microscopy images confirmed the uptake of DOX loaded (or conjugated) nano-vesicles by cells compared to free DOX. Thus, the newly developed pH and enzyme dual responsive polysaccharide vesicular assemblies are potential drug vectors for the administration of DOX in both loaded and chemically conjugated forms for the efficient killing of breast cancer cells.The present work reports the development of pH and enzyme dual responsive polysaccharide vesicular nano-scaffolds for the administration of doxorubicin via physical loading and polymer-drug conjugation to breast cancer cells. Dextran was suitably modified with a renewable resource 3-pentadecyl phenol unit through imine and aliphatic ester chemical linkages that acted as pH and esterase enzyme stimuli, respectively. These dual responsive polysaccharide derivatives self-organized into 200 +/- 10 nm diameter nano-vesicles in water. The water soluble anticancer drug doxorubicin (DOX.HCl) was encapsulated in the hydrophilic pocket to produce core-loaded polysaccharide vesicles whereas chemical conjugation produced DOX anchored at the hydrophobic layer of the dextran nano-vesicles. In vitro studies revealed that about 70-80% of the drug was retained under circulatory conditions at pH = 7.4 and 37 °C. At a low pH of 6.0 to 5.0 and in the presence of esterase; both imine and ester linkages were cleaved instantaneously to release 100% of the loaded drugs. Cytotoxicity assays on Wild Type Mouse Embryonic Fibroblasts (WTMEFs) confirmed the non-toxicity of the newly developed dextran derivatives at up to 500 μg mL-1 in PBS. MTT assays on fibroblast cells revealed that DOX.HCl loaded nano-vesicles exhibited better killing abilities than DOX conjugated polymer nano-vesicles. Both DOX loaded and DOX conjugated nano-vesicles were found to show significant killing in breast cancer cells (MCF 7). Confocal microscopy images confirmed the uptake of DOX loaded (or conjugated) nano-vesicles by cells compared to free DOX. Thus, the newly developed pH and enzyme dual responsive polysaccharide vesicular assemblies are potential drug vectors for the administration of DOX in both loaded and chemically conjugated forms for the efficient killing of breast cancer cells. Electronic supplementary information (ESI) available: 13C NMR of DEX-CHO, 2D NMR spectra of DEX-CHO, 1H NMR of DEX-IM, 1H NMR of DEX-IM-DOX conjugated, absorbance spectra of DEX-IM-DOX conjugated, DLS, FE-SEM and TEM image of DEX-CHO-5, emission spectra of pyrene and Nile red with DEX-IM-10, FE-SEM image of DEX-IM-DOX loaded, FE-SEM image of acid treated DEX-IM-5, absorbance spectra of DOX released, in vitro DOX release from drug loaded and conjugated vesicles in the presence of serum (FBS), DLS data depicting stability of DEX-IM vesicles in serum (FBS), 1HNMR, 13C NMR and HR-MS spectra of all intermediates are provided. See DOI: 10.1039/c5nr00799b

Imaging burst kinetics and spatial coordination during serial killing by single natural killer cells

PubMed Central

Choi, Paul J.; Mitchison, Timothy J.

2013-01-01

Cytotoxic lymphocytes eliminate virus-infected and cancerous cells by immune recognition and killing through the perforin-granzyme pathway. Traditional killing assays measure average target cell lysis at fixed times and high effector:target ratios. Such assays obscure kinetic details that might reveal novel physiology. We engineered target cells to report on granzyme activity, used very low effector:target ratios to observe potential serial killing, and performed low magnification time-lapse imaging to reveal time-dependent statistics of natural killer (NK) killing at the single-cell level. Most kills occurred during serial killing, and a single NK cell killed up to 10 targets over a 6-h assay. The first kill was slower than subsequent kills, especially on poor targets, or when NK signaling pathways were partially inhibited. Spatial analysis showed that sequential kills were usually adjacent. We propose that NK cells integrate signals from the previous and current target, possibly by simultaneous contact. The resulting burst kinetics and spatial coordination may control the activity of NK cells in tissues. PMID:23576740

It's not just conflict that motivates killing of orangutans.

PubMed

Davis, Jacqueline T; Mengersen, Kerrie; Abram, Nicola K; Ancrenaz, Marc; Wells, Jessie A; Meijaard, Erik

2013-01-01

We investigated why orangutans are being killed in Kalimantan, Indonesia, and the role of conflict in these killings. Based on an analysis of interview data from over 5,000 respondents in over 450 villages, we also assessed the socio-ecological factors associated with conflict and non-conflict killings. Most respondents never kill orangutans. Those who reported having personally killed an orangutan primarily did so for non-conflict reasons; for example, 56% of these respondents said that the reason they had killed an orangutan was to eat it. Of the conflict-related reasons for killing, the most common reasons orangutans were killed was fear of orangutans or in self-defence. A similar pattern was evident among reports of orangutan killing by other people in the villages. Regression analyses indicated that religion and the percentage of intact forest around villages were the strongest socio-ecological predictors of whether orangutans were killed for conflict or non-conflict related reasons. Our data indicate that between 44,170 and 66,570 orangutans were killed in Kalimantan within the respondents' active hunting lifetimes: between 12,690 and 29,024 for conflict reasons (95%CI) and between 26,361 and 41,688 for non-conflict reasons (95% CI). These findings confirm that habitat protection alone will not ensure the survival of orangutans in Indonesian Borneo, and that effective reduction of orangutan killings is urgently needed.

It’s Not Just Conflict That Motivates Killing of Orangutans

PubMed Central

Davis, Jacqueline T.; Mengersen, Kerrie; Abram, Nicola K.; Ancrenaz, Marc; Wells, Jessie A.; Meijaard, Erik

2013-01-01

We investigated why orangutans are being killed in Kalimantan, Indonesia, and the role of conflict in these killings. Based on an analysis of interview data from over 5,000 respondents in over 450 villages, we also assessed the socio-ecological factors associated with conflict and non-conflict killings. Most respondents never kill orangutans. Those who reported having personally killed an orangutan primarily did so for non-conflict reasons; for example, 56% of these respondents said that the reason they had killed an orangutan was to eat it. Of the conflict-related reasons for killing, the most common reasons orangutans were killed was fear of orangutans or in self-defence. A similar pattern was evident among reports of orangutan killing by other people in the villages. Regression analyses indicated that religion and the percentage of intact forest around villages were the strongest socio-ecological predictors of whether orangutans were killed for conflict or non-conflict related reasons. Our data indicate that between 44,170 and 66,570 orangutans were killed in Kalimantan within the respondents’ active hunting lifetimes: between 12,690 and 29,024 for conflict reasons (95%CI) and between 26,361 and 41,688 for non-conflict reasons (95% CI). These findings confirm that habitat protection alone will not ensure the survival of orangutans in Indonesian Borneo, and that effective reduction of orangutan killings is urgently needed. PMID:24130707

Asymmetric effects of native and exotic invasive shrubs on ecology of the West Nile virus vector Culex pipiens (Diptera: Culicidae).

PubMed

Gardner, Allison M; Allan, Brian F; Frisbie, Lauren A; Muturi, Ephantus J

2015-06-16

Exotic invasive plants alter the structure and function of native ecosystems and may influence the distribution and abundance of arthropod disease vectors by modifying habitat quality. This study investigated how invasive plants alter the ecology of Culex pipiens, an important vector of West Nile virus (WNV) in northeastern and midwestern regions of the United States. Field and laboratory experiments were conducted to test the hypothesis that three native leaf species (Rubus allegheniensis, blackberry; Sambucus canadensis, elderberry; and Amelanchier laevis, serviceberry), and three exotic invasive leaf species (Lonicera maackii, Amur honeysuckle; Elaeagnus umbellata, autumn olive; and Rosa multiflora, multiflora rose) alter Cx. pipiens oviposition site selection, emergence rates, development time, and adult body size. The relative abundance of seven bacterial phyla in infusions of the six leaf species also was determined using quantitative real-time polymerase chain reaction to test the hypothesis that variation in emergence, development, and oviposition site selection is correlated to differences in the diversity and abundance of bacteria associated with different leaf species, important determinants of nutrient quality and availability for mosquito larvae. Leaf detritus from invasive honeysuckle and autumn olive yielded significantly higher adult emergence rates compared to detritus from the remaining leaf species and honeysuckle alleviated the negative effects of intraspecific competition on adult emergence. Conversely, leaves of native blackberry acted as an ecological trap, generating high oviposition but low emergence rates. Variation in bacterial flora associated with different leaf species may explain this asymmetrical production of mosquitoes: emergence rates and oviposition rates were positively correlated to bacterial abundance and diversity, respectively. We conclude that the displacement of native understory plant species by certain invasive shrubs may increase production of Cx. pipiens with potential negative repercussions for human and wildlife health. These findings may be relevant to mosquito control and invasive plant management practices in the geographic range of Cx. pipiens. Further, our discovery of a previously unknown ecological trap for an important vector of WNV has the potential to lead to novel alternatives to conventional insecticides in mosquito control by exploiting the apparent "attract-kill" properties of this native plant species.

From Attitudes to Actions: Predictors of Lion Killing by Maasai Warriors.

PubMed

Hazzah, Leela; Bath, Alistair; Dolrenry, Stephanie; Dickman, Amy; Frank, Laurence

2017-01-01

Despite legal protection, deliberate killing by local people is one of the major threats to the conservation of lions and other large carnivores in Africa. Addressing this problem poses particular challenges, mainly because it is difficult to uncover illicit behavior. This article examined two groups of Maasai warriors: individuals who have killed African lions (Panthera leo) and those who have not. We conducted interviews to explore the relationship between attitudes, intentions and known lion killing behavior. Factor analysis and logistic regression revealed that lion killing was mainly determined by: (a) general attitudes toward lions, (b) engagement in traditional customs, (c) lion killing intentions to defend property, and (d) socio-cultural killing intentions. Our results indicated that general attitudes toward lions were the strongest predictor of lion killing behavior. Influencing attitudes to encourage pro-conservation behavior may help reduce killing.

Wolf-bison interactions in Yellowstone National Park

USGS Publications Warehouse

Smith, Douglas W.; Mech, L. David; Meagher, Mary; Clark, Wendy E.; Jaffe, Rosemary; Phillips, Michael K.; Mack, John A.

2000-01-01

We studied interactions of reintroduced wolves (Canis lupus) with bison (Bison bison) in Yellowstone National Park. Only 2 of 41 wolves in this study had been exposed to bison before their translocation. Wolves were more successful killing elk (Cervus elaphus) than bison, and elk were more abundant than bison, so elk were the primary prey of wolves. Except for a lone emaciated bison calf killed by 8 1-year-old wolves 21 days after their release, the 1st documented kill occurred 25 months after wolves were released. Fourteen bison kills were documented from April 1995 through March 1999. All kills were made in late winter when bison were vulnerable because of poor condition or of bison that were injured or young. Wolves learned to kill bison and killed more bison where elk were absent or scarce. We predict that wolves that have learned to kill bison will kill them more regularly, at least in spring. The results of this study indicate how adaptable wolves are at killing prey species new to them.

Field experiments of Anopheles gambiae attraction to local fruits/seedpods and flowering plants in Mali to optimize strategies for malaria vector control in Africa using attractive toxic sugar bait methods.

PubMed

Müller, Günter C; Beier, John C; Traore, Sekou F; Toure, Mahamoudou B; Traore, Mohamed M; Bah, Sekou; Doumbia, Seydou; Schlein, Yosef

2010-09-20

Based on recent studies in Israel demonstrating that attractive toxic sugar bait (ATSB) methods can be used to decimate local anopheline and culicine mosquito populations, an important consideration is whether the same methods can be adapted and improved to attract and kill malaria vectors in Africa. The ATSB approach uses fruit or flower scent as an attractant, sugar solution as a feeding stimulant, and an oral toxin. The ATSB solutions are either sprayed on vegetation or suspended in simple bait stations, and the mosquitoes ingesting the toxic solutions are killed. As such, this approach targets sugar-feeding female and male mosquitoes. This study examines the attractiveness of African malaria vectors to local fruits/seedpods and flowering plants, key biological elements of the ATSB approach for mosquito control. Three field experiments were conducted at sites in Mali. The attraction of Anopheles gambiae s.l. to 26 different local fruits and seedpods was determined at a site in the semi-arid Bandiagara District of Mali. Wire mesh glue traps with fruits/seedpods suspended on skewers inside were set along a seasonal lagoon. Seven replicates of each fruit/seedpod species were tested, with a water-soaked sponge and a sugar-soaked sponge as controls. The attraction of An. gambiae s.l. to 26 different types of flowering plants was determined at a site near Mopti in Mali. The flowering plants held in a water-filled buried container were tested using the same glue traps, with controls including water only and sugar solution. Six replicates of each selected plant type were tested on transects between rice paddies. Additional studies using CDC light traps were done to determine the relative densities and periodicity of An. gambiae s.l. attraction to branches of the most highly attractive flowering plant, branches without flowers, human odor, and candescent light. Of the 26 fruits and seedpods tested, 6 were attractive to An. gambiae s.l. females and males, respectively. Guava (Psidium guajava) and honey melon (Cucumis melo) were the two most attractive fruits for both females and males. Of the 26 flowering plants tested, 9 were significantly attractive for females, and 8 were attractive for males. Acacia macrostachya was the most attractive flowering plant. Periodicity studies using this plant showed peaks of An. gambiae s.l. attraction between 1930 and 2200 h and 0400-0500 h, which differed considerably from the response to human odors, which expectedly peaked at around midnight. These field experiments in Mali highlight that female and male An. gambiae s.l. have pronounced differences in attraction for diverse types of indigenous fruits/seedpods and flowering plants. The identification of attractive fruits and seedpods shows that a variety of indigenous and locally abundant natural products could potentially be used as juices to make ATSB solution for mosquito control. As well, the simple methods used to identify the most attractive flowering plants provide valuable insights into the natural history of sugar feeding for An. gambiae s.l. These observations can be used to guide future strategies for employing ATSB methods for malaria vector control in Africa. They also provide a basis for subsequent chemical analysis and development of attractive baits for mosquito control.

Field experiments of Anopheles gambiae attraction to local fruits/seedpods and flowering plants in Mali to optimize strategies for malaria vector control in Africa using attractive toxic sugar bait methods

PubMed Central

2010-01-01

Background Based on recent studies in Israel demonstrating that attractive toxic sugar bait (ATSB) methods can be used to decimate local anopheline and culicine mosquito populations, an important consideration is whether the same methods can be adapted and improved to attract and kill malaria vectors in Africa. The ATSB approach uses fruit or flower scent as an attractant, sugar solution as a feeding stimulant, and an oral toxin. The ATSB solutions are either sprayed on vegetation or suspended in simple bait stations, and the mosquitoes ingesting the toxic solutions are killed. As such, this approach targets sugar-feeding female and male mosquitoes. This study examines the attractiveness of African malaria vectors to local fruits/seedpods and flowering plants, key biological elements of the ATSB approach for mosquito control. Methods Three field experiments were conducted at sites in Mali. The attraction of Anopheles gambiae s.l. to 26 different local fruits and seedpods was determined at a site in the semi-arid Bandiagara District of Mali. Wire mesh glue traps with fruits/seedpods suspended on skewers inside were set along a seasonal lagoon. Seven replicates of each fruit/seedpod species were tested, with a water-soaked sponge and a sugar-soaked sponge as controls. The attraction of An. gambiae s.l. to 26 different types of flowering plants was determined at a site near Mopti in Mali. The flowering plants held in a water-filled buried container were tested using the same glue traps, with controls including water only and sugar solution. Six replicates of each selected plant type were tested on transects between rice paddies. Additional studies using CDC light traps were done to determine the relative densities and periodicity of An. gambiae s.l. attraction to branches of the most highly attractive flowering plant, branches without flowers, human odor, and candescent light. Results Of the 26 fruits and seedpods tested, 6 were attractive to An. gambiae s.l. females and males, respectively. Guava (Psidium guajava) and honey melon (Cucumis melo) were the two most attractive fruits for both females and males. Of the 26 flowering plants tested, 9 were significantly attractive for females, and 8 were attractive for males. Acacia macrostachya was the most attractive flowering plant. Periodicity studies using this plant showed peaks of An. gambiae s.l. attraction between 1930 and 2200 h and 0400-0500 h, which differed considerably from the response to human odors, which expectedly peaked at around midnight. Conclusion These field experiments in Mali highlight that female and male An. gambiae s.l. have pronounced differences in attraction for diverse types of indigenous fruits/seedpods and flowering plants. The identification of attractive fruits and seedpods shows that a variety of indigenous and locally abundant natural products could potentially be used as juices to make ATSB solution for mosquito control. As well, the simple methods used to identify the most attractive flowering plants provide valuable insights into the natural history of sugar feeding for An. gambiae s.l. These observations can be used to guide future strategies for employing ATSB methods for malaria vector control in Africa. They also provide a basis for subsequent chemical analysis and development of attractive baits for mosquito control. PMID:20854666

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Feline Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Feline Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Pseudorabies Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine, Killed... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All...

9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Pseudorabies Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine, Killed... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All...

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Feline Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Feline Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Pseudorabies Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine, Killed... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All...

9 CFR 113.211 - Feline Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Feline Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.211 Feline Rhinotracheitis Vaccine, Killed Virus. Feline Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Pseudorabies Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine, Killed... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All...

9 CFR 113.213 - Pseudorabies Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Pseudorabies Vaccine, Killed Virus... REQUIREMENTS Killed Virus Vaccines § 113.213 Pseudorabies Vaccine, Killed Virus. Pseudorabies Vaccine, Killed... established as pure, safe, and immunogenic shall be used for preparing seeds for vaccine production. All...

9 CFR 113.210 - Feline Calicivirus Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Feline Calicivirus Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.210 Feline Calicivirus Vaccine, Killed Virus. Feline Calicivirus Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Feline Panleukopenia Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.216 - Bovine Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Bovine Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.216 Bovine Rhinotracheitis Vaccine, Killed Virus. Infectious Bovine Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Feline Panleukopenia Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.216 - Bovine Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Bovine Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.216 Bovine Rhinotracheitis Vaccine, Killed Virus. Infectious Bovine Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...

9 CFR 113.210 - Feline Calicivirus Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Feline Calicivirus Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.210 Feline Calicivirus Vaccine, Killed Virus. Feline Calicivirus Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.203 - Feline Panleukopenia Vaccine, Killed Virus.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Feline Panleukopenia Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.203 Feline Panleukopenia Vaccine, Killed Virus. Feline Panleukopenia Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed which...

9 CFR 113.216 - Bovine Rhinotracheitis Vaccine, Killed Virus.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Bovine Rhinotracheitis Vaccine, Killed... REQUIREMENTS Killed Virus Vaccines § 113.216 Bovine Rhinotracheitis Vaccine, Killed Virus. Infectious Bovine Rhinotracheitis Vaccine, Killed Virus, shall be prepared from virus-bearing cell culture fluids. Only Master Seed...