2,706 research outputs found
Magnetic Field Generation from Self-Consistent Collective Neutrino-Plasma Interactions
A new Lagrangian formalism for self-consistent collective neutrino-plasma
interactions is presented in which each neutrino species is described as a
classical ideal fluid. The neutrino-plasma fluid equations are derived from a
covariant relativistic variational principle in which finite-temperature
effects are retained. This new formalism is then used to investigate the
generation of magnetic fields and the production of magnetic helicity as a
result of collective neutrino-plasma interactions.Comment: 23 page
HRM in Multinationals’ Operations in China: Business, People, and HR Issues
This paper presents the results of a study on the HR function in the Chinese operations of large multinational companies. Surveys of both line and HR executives in these firms were conducted. Results reveal that line executives are more sensitive than HR executives to criticality of people management issues as business issues, and that they see HR\u27s strategic orientation as the most critical area for improvement. The challenges and opportunities implied by these results are discussed
Aleph_null Hypergravity in Three-Dimensions
We construct hypergravity theory in three-dimensions with the gravitino
\psi_{\mu m_1... m_n}{}^A with an arbitrary half-integral spin n+3/2, carrying
also the index A for certain real representations of any gauge group G. The
possible real representations are restricted by the condition that the matrix
representation of all the generators are antisymmetric: (T^I)^{A B} = -
(T^I)^{B A}. Since such a real representation can be arbitrarily large, this
implies \aleph_0-hypergravity with infinitely many (\aleph_0) extended local
hypersymmetries.Comment: 12 pages, no figure
Non-Abelian Tensors with Consistent Interactions
We present a systematic method for constructing consistent interactions for a
tensor field of an arbitrary rank in the adjoint representation of an arbitrary
gauge group in any space-time dimensions. This method is inspired by the
dimensional reduction of Scherk-Schwarz, modifying field strengths with certain
Chern-Simons forms, together with modified tensorial gauge transformations. In
order to define a consistent field strength of a r-rank tensor
B_{\mu_1...\mu_r}^I in the adjoint representation, we need the multiplet
(B_{\mu_1...\mu_r}^I, B_{\mu_1...\mu_{r-1}}^{I J}, ..., B_\mu^{I_1...I_r},
B^{I_1... I_{r+1}}). The usual problem of consistency of the tensor field
equations is circumvented in this formulation.Comment: 15 pages, no figure
High-Energy Neutrino Signatures of Dark Matter Decaying into Leptons
Decaying dark matter has previously been proposed as a possible explanation
for the excess high energy cosmic ray electrons and positrons seen by PAMELA
and the Fermi Gamma-Ray Space Telescope (FGST). To accommodate these signals
however, the decays must be predominantly leptonic, to muons or taus, and
therefore produce neutrinos, potentially detectable with the IceCube neutrino
observatory. We find that, with five years of data, IceCube (supplemented by
DeepCore) will be able to significantly constrain the relevant parameter space
of decaying dark matter, and may even be capable of discovering dark matter
decaying in the halo of the Milky Way.Comment: 4 pages, 1 figur
Dilaton and Second-Rank Tensor Fields as Supersymmetric Compensators
We formulate a supersymmetric theory in which both a dilaton and a
second-rank tensor play roles of compensators. The basic off-shell multiplets
are a linear multiplet (B_{\mu\nu}, \chi, \phi) and a vector multiplet (A_\mu,
\l; C_{\mu\nu\rho}), where \phi and B_{\m\n} are respectively a dilaton and a
second-rank tensor. The third-rank tensor C_{\mu\nu\rho} in the vector
multiplet is 'dual' to the conventional D-field with 0 on-shell or 1 off-shell
degree of freedom. The dilaton \phi is absorbed into one longitudinal component
of A_\mu, making it massive. Initially, B_{\mu\nu} has 1 on-shell or 3
off-shell degrees of freedom, but it is absorbed into the longitudinal
components of C_{\mu\nu\rho}. Eventually, C_{\mu\nu\rho} with 0 on-shell or 1
off-shell degree of freedom acquires in total 1 on-shell or 4 off-shell degrees
of freedom, turning into a propagating massive field. These basic multiplets
are also coupled to chiral multiplets and a supersymmetric Dirac-Born-Infeld
action. Some of these results are also reformulated in superspace. The proposed
mechanism may well provide a solution to the long-standing puzzle of massless
dilatons and second-rank tensors in supersymmetric models inspired by string
theory.Comment: 15 pages, no figure
Vascular endothelial growth factor directly inhibits primitive neural stem cell survival but promotes definitive neural stem cell survival
There are two types of neural stem cells (NSCs). Primitive NSCs [leukemia inhibitory factor (LIF) dependent but exogenous fibroblast growth factor (FGF) 2 independent] can be derived from mouse embryonic stem (ES) cells in vitro and from embryonic day 5.5 (E5.5) to E7.5 epiblast and E7.5-E8.5 neuroectoderm in vivo. Definitive NSCs (LIF independent but FGF2 dependent) first appear in the E8.5 neural plate and persist throughout life. Primitive NSCs give rise to definitive NSCs. Loss and gain of functions were used to study the role of vascular endothelial growth factor (VEGF)-A and its receptor, Flk1, in NSCs. The numbers of Flk1 knock-out mice embryo-derived and ES cell-derived primitive NSCs were increased because of the enhanced survival of primitive NSCs. In contrast, neural precursor-specific, Flk1 conditional knock-out mice-derived, definitive NSCs numbers were decreased because of the enhanced cell death of definitive NSCs. These effects were not observed in cells lacking Flt1, another VEGF receptor. In addition, the cell death stimulated by VEGF-A of primitive NSC and the cell survival stimulated by VEGF-A of definitive NSC were blocked by Flk1/Fc-soluble receptors and VEGF-A function-blocking antibodies. These VEGF-A phenotypes also were blocked by inhibition of the downstream effector nuclear factor kappa B (NF-kappa B). Thus, both the cell death of primitive NSC and the cell survival of definitive NSC induced by VEGF-A stimulation are mediated by bifunctional NF-kappa B effects. In conclusion, VEGF-A function through Flk1 mediates survival (and not proliferative or fate change) effects on NSCs, specifically
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