278 research outputs found
Extra bosons and low-energy tests of unification
If there is an extra U(1) gauge symmetry broken at low energies, then it may
be possible from the charges of the known quarks and leptons under this U(1) to
make inferences about how much gauge unification occurs at high scales and
about the unification group. (For instance, there are certain observed
properties of an extra that would be inconsistent with unification in
four dimensions at high scales.) A general analysis is presented. Two criteria
used in this analysis are (1) the degree to which the generator of the extra
U(1) mixes with hypercharge, and (2) the ratio of the extra U(1) charge of the
"10" and the "" of quarks and leptons.Comment: 27 pages, LaTex, no figures. Changed content. References added. Typos
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Waterlogging and salinity management in the Sindh Province. Volume 1 - The irrigated landscape: resource availability across the hydrological divides
Irrigation management / River basins / Irrigated farming / Climate / Irrigation systems / Irrigation canals / Discharges / Water balance / Waterlogging / Salinity / Groundwater development / Tube wells / Water table / Drainage / Public sector / Land reclamation / Pakistan / Sindh Province / Indus Basin / Rohri / Larkana / Shikarpur / Hairdin / North Dadu / Ghotki / East Khairpur / Sukkur Barrage
Spin rotation for ballistic electron transmission induced by spin-orbit interaction
We study spin dependent electron transmission through one- and
two-dimensional curved waveguides and quantum dots with account of spin-orbit
interaction. We prove that for a transmission through arbitrary structure there
is no spin polarization provided that electron transmits in isolated energy
subband and only two leads are attached to the structure. In particular there
is no spin polarization in the one-dimensional wire for which spin dependent
solution is found analytically. The solution demonstrates spin evolution as
dependent on a length of wire. Numerical solution for transmission of electrons
through the two-dimensional curved waveguides coincides with the solution for
the one-dimensional wire if the energy of electron is within the first energy
subband. In the vicinity of edges of the energy subbands there are sharp
anomalies of spin flipping.Comment: 9 oages, 7 figure
The Role of Endothelium-Derived Relaxing Factor in The Regulation of SNP Induced Vasorelaxation: Sodium-Potassium-Chloride Cotransporter
Vascular endothelium plays a key role in the local regulation of vascular tone and vascular architecture. However, it is unclear whether the combination of NKCC cotransporter with endothelial mediated factor and potassium channel in rat aortic ring contributes in regulation of the vascular activity. In the current study, the potential role of endothelium-mediated relaxing factors and potassium channel in SNP induced vasorelaxation in precontracted isolated rat aortic rings in the presence of Bumetanide as NKCC blocker were investigated. The maximum vasorelaxation induced by SNP significantly blocked by the presence BUM. SNP induced relaxation was affected by combination of BUM with Indomethacin, Clotrimazole. TEA and BaCl2 significantly blocked of SNP induced relaxation in aorta preincubated with all blockers used, but BaCl2 showed a more potent effect as compared with others. These results indicate that  SNP – induced vasorelaxation was mediated via  EETs, Prostaglandin, BKCa and KIR pathways which ultimately enhanced the contribution of chloride transporter in aortic smooth muscle cells hyperpolarization and subsequent relaxation
S-matrix theory for transmission through billiards in tight-binding approach
In the tight-binding approximation we consider multi-channel transmission
through a billiard coupled to leads. Following Dittes we derive the coupling
matrix, the scattering matrix and the effective Hamiltonian, but take into
account the energy restriction of the conductance band. The complex eigenvalues
of the effective Hamiltonian define the poles of the scattering matrix. For
some simple cases, we present exact values for the poles. We derive also the
condition for the appearance of double poles.Comment: 29 pages, 9 figures, submitted to J. Phys. A: Math. and Ge
Distribution of nearest distances between nodal points for the Berry function in two dimensions
According to Berry a wave-chaotic state may be viewed as a superposition of
monochromatic plane waves with random phases and amplitudes. Here we consider
the distribution of nodal points associated with this state. Using the property
that both the real and imaginary parts of the wave function are random Gaussian
fields we analyze the correlation function and densities of the nodal points.
Using two approaches (the Poisson and Bernoulli) we derive the distribution of
nearest neighbor separations. Furthermore the distribution functions for nodal
points with specific chirality are found. Comparison is made with results from
from numerical calculations for the Berry wave function.Comment: 11 pages, 7 figure
The impact of relative position and returns on sacrifice and reciprocity: an experimental study using individual decisions
We present a comprehensive experimental design that makes it possible to characterize other-regarding preferences and their relationship to the decision maker’s relative position. Participants are faced with a large number of decisions involving variations in the trade-offs between own and other’s payoffs, as well as in other potentially important factors like the decision maker’s relative position. We find that: (1) choices are responsive to the cost of helping and hurting others; (2) The weight a decision maker places on others’ monetary payoffs depends on whether the decision maker is in an advantageous or disadvantageous relative position; and (3) We find no evidence of reciprocity of the type linked to menu-dependence. The results of a mixture-model estimation show considerable heterogeneity in subjects’ motivations and confirm the absence of reciprocal motives. Pure selfish behavior is the most frequently observed behavior. Among the subjects exhibiting social preferences, social-welfare maximization is the most frequent, followed by inequality-aversion and by competitiveness
CD8+ T lymphocyte responses target functionally important regions of Protease and Integrase in HIV-1 infected subjects
BACKGROUND: CD8+ T cell responses are known to be important to the control of HIV-1 infection. While responses to reverse transcriptase and most structural and accessory proteins have been extensively studied, CD8 T cell responses specifically directed to the HIV-1 enzymes Protease and Integrase have not been well characterized, and few epitopes have been described in detail. METHODS: We assessed comprehensively the CD8 T cell responses to synthetic peptides spanning Protease and Integrase in 56 HIV-1 infected subjects with acute, chronic, or controlled infection using IFN-Îł-Elispot assays and intracellular cytokine staining. Fine-characterization of novel CTL epitopes was performed on peptide-specific CTL lines in Elispot and (51)Chromium-release assays. RESULTS: Thirteen (23%) and 38 (68%) of the 56 subjects had detectable responses to Protease and Integrase, respectively, and together these targeted most regions within both proteins. Sequence variability analysis confirmed that responses cluster largely around conserved regions of Integrase, but responses against a large, highly conserved region of the N-terminal DNA-binding domain of Integrase were not readily detected. CD8 T cell responses targeted regions of Protease that contain known Protease inhibitor mutation residues, but strong Protease-specific CD8 T cell responses were rare. Fine-mapping of targeted epitopes allowed the identification of three novel, HLA class I-restricted, frequently-targeted optimal epitopes. There were no significant correlations between CD8 T cell responses to Protease and Integrase and clinical disease category in the study subjects, nor was there a correlation with viral load. CONCLUSIONS: These findings confirm that CD8 T cell responses directed against HIV-1 include potentially important functional regions of Protease and Integrase, and that pharmacologic targeting of these enzymes will place them under both drug and immune selection pressure
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