Homotheties and topology of tangent sphere bundles

We prove a Theorem on homotheties between two given tangent sphere bundles $S_rM$ of a Riemannian manifold $M,g$ of $\dim\geq 3$, assuming different variable radius functions $r$ and weighted Sasaki metrics induced by the conformal class of $g$. New examples are shown of manifolds with constant positive or with constant negative scalar curvature, which are not Einstein. Recalling results on the associated almost complex structure $I^G$ and symplectic structure ${\omega}^G$ on the manifold $TM$, generalizing the well-known structure of Sasaki by admitting weights and connections with torsion, we compute the Chern and the Stiefel-Whitney characteristic classes of the manifolds $TM$ and $S_rM$.Comment: 15 pages, to appear in Journal of Geometr

Can an odd number of fermions be created due to chiral anomaly?

We describe a possibility of creation of an odd number of fractionally charged fermions in 1+1 dimensional Abelian Higgs model. We point out that for 1+1 dimensions this process does not violate any symmetries of the theory, nor makes it mathematically inconsistent. We construct the proper definition of the fermionic determinant in this model and underline its non-trivial features that are of importance for realistic 3+1 dimensional models with fermion number violation.Comment: 12 pages revtex, 2 figure

An Accurate Method for Extracting the Critical Field in Short Channel NMOS Devices

In this letter, an accurate method for extracting the critical field Ec in short channel MOSFET's is presented. The principle of this method is based on the comparison between two models which give drain saturation voltage evolution against gate voltage Vdsat(Vg) continuously. The results obtained by this technique have shown better agreement with measurements data and have allow in the same time to determine the validity domain of Sodini's law [1]

Thermomechanical force application

The present work conducted in Summer 1987 continues investigations on Thermal Components for 1.8 K Space Cryogenics (Grant NAG 1-412 of 1986). The topics addressed are plug characterization efforts in a small pore size regime of sintered metal plugs, characterization in the nonlinear regime, temperature profiles in a heat supply unit for a fountain effect pump and modeling efforts

Utilization of FEP energetics

The research and development work on Fountain Effect Pump Systems (FEP systems) has been of interest in the competition between mechanical pumps for He II and FEP units. The latter do not have moving parts. In the course of the work, the energetics have been addressed using one part of a simple four-changes-of-state cycle. One option is the FEP ideal change of state at constant chemical potential (mu). The other option is the two-state sequence mu-P with a d mu=0 state change followed by an isobar. Questions of pump behavior, of flow rate response to temperature difference at the hot end, and related questions of thermodynamic cycle completion and heat transfer have been addressed. Porous media data obtained elucidate differences between vapor-liquid phase separation (VLPS) and Zero Net Mass Transfer (ZNMF)

Vertically Self-Gravitating ADAFs in the Presence of Toroidal Magnetic Field

Force due to the self-gravity of the disc in the vertical direction is considered to study its possible effects on the structure of a magnetized advection-dominated accretion disc. We present steady-sate self similar solutions for the dynamical structure of such a type of the accretion flows. Our solutions imply reduced thickness of the disc because of the self-gravity. It also imply that the thickness of the disc will increase by adding the magnetic field strength.Comment: Accepted for publication in Astrophysics and Space Science

The Cytotoxic Effect of 2-Deoxy-D-Glucose Combination with 5-Fluorourasil and NO-Aspirin on Mammary Adenocacinoma Cell Line

2-deoxy-D-glucose (2DG) and NO-Aspirin (NO-ASA) are new anticancer agents that are under intense clinical investigation for their remarkable cytotoxic activity. Combining 2DG, which targets glucose metabolism, with other agents mainly the DNA- and the mitochondrial-damaging agents represent a promising chemotherapeutic strategy.  In this study, we investigated the cytotoxic effects of 2DG, 5-fluorourasil (5FU), and NO-ASA on AMN3 breast cancer model, in addition to the cytotoxic effects of 2DG combination with 5FU and NO-ASA on the same cells. The cytotoxic activity of 2DG, 5FU, and NO-ASA was measured by using the MTT assay at 24, 48, and 72 hr. Then 2DG was combined with 5FU and NO-ASA in a constant concentration ratio based on their corresponding IC50s and the inhibition of cell growth was measured by MTT assay at 72hr. Median effect analysis was conducted to determine the cytotoxic activity of the combinations. 2DG, 5FU, and NO-ASA were found to exert a significant dose- and time-dependant growth inhibition on AMN3 cells. The mean combination index values reveal an additive effect for both combinations. This study demonstrated that 2DG and NO-ASA are capable of inhibiting the breast tumor growth effectively. It also shows that 2DG/5FU and 2DG/NO-ASA combinations result in mean additive effects with good dose reduction index values that have the advantages of reducing the toxicity, adverse effects, and the drug resistance in cancer patients. Key words: 2-deoxy-D-glucose (2DG), NO-Aspirin (NO-ASA), 5-fluorourasil (5FU), Glucose metabolism, Median effect analysis, Breast cance

A Physical Model for MOSFET Drain Current in Non-ohmic Regime Using Ohmic Regime Operation

In order to characterise the velocity saturation phenomena in short channel MOSFET's, a simple method is proposed in this work. It is based on the comparison between transistor behaviour in ohmic and saturation regime respectively. Therefore, the MOSFET characteristic Id0(Vd). avoiding velocity saturation phenomena, can be obtained from ohmic characteristic Id(Vg) and compared with the experimental characteristic Id(Vd)

Distribution of Energy-Momentum in a Schwarzschild-Quintessence Space-time Geometry

An analysis of the energy-momentum localization for a four-dimensional\break Schwarzschild black hole surrounded by quintessence is presented in order to provide expressions for the distributions of energy and momentum. The calculations are performed by using the Landau-Lifshitz and Weinberg energy-momentum complexes. It is shown that all the momenta vanish, while the expression for the energy depends on the mass $M$ of the black hole, the state parameter $w_{q}$ and the normalization factor $c$. The special case of $w_{q}=-2/3$ is also studied, and two limiting cases are examined.Comment: 9 page