4,274 research outputs found

    Realistic Gluino Axion Model Consistent with Supersymmetry Breaking at the TeV Scale

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    The recently proposed model of using the dynamical phase of the gluino to solve the strong CP problem is shown to admit a specific realization in terms of fundamental singlet superfields, such that the breaking of supersymmetry occurs only at the TeV scale, despite the large axion scale of 10^{9} to 10^{12} GeV. Phenomenological implications are discussed.Comment: 12 pp, 2 fig

    Increased expression of matrix metalloproteinase-9 in patients with temporal lobe epilepsy

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    Aim: The molecular mechanism of epileptogenesis in temporal lobe epilepsy is still unclear. Experimental studies have suggested that matrix metalloproteinases have important roles in this process, but human studies are limited. The aim of this study was to assess the expression of MMP-9, MMP-2 and their tissue inhibitors (TIMP-1 and TIMP-2) in patients with temporal lobe epilepsy with hippocampal sclerosis (TLE-HS). Material and Methods: The tissue samples from temporal neocortex and hippocampus were obtained from patients with temporal lobe epilepsy with hippocampal sclerosis who had undergone anterior temporal lobectomy for recurrent medically resistant seizures. Immunohistochemical methods were used to determine the expression of MMP-9, MMP-2 and their tissue inhibitors. Tissue samples were also analyzed with transmission electron microscopy. Results: The immunoreactivity for MMP-9 both in hippocampal and temporal neocortical neurons was stronger than that of MMP-2. Additionally, there was a mild reaction for its tissue inhibitor TIMP-1 as with TIMP-2. The TEM analysis of the hippocampus revealed that there was apparent ultra-structural damage on the pericarya and neuropil of some neurons. There was obvious damage in the mitochondria and the nuclear membrane. Conclusion: The preliminary results of this study revealed that MMP-9 may have a role in patients with drug resistant TLE-HS

    Identification of the Atomic Scale Structures of the Gold-Thiol Interfaces of Molecular Nanowires by Inelastic Tunneling Spectroscopy

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    We examine theoretically the effects of the bonding geometries at the gold-thiol interfaces on the inelastic tunneling spectra of propanedithiolate (PDT) molecules bridging gold electrodes and show that inelastic tunneling spectroscopy combined with theory can be used to determine these bonding geometries experimentally. With the help of density functional theory, we calculate the relaxed geometries and vibrational modes of extended molecules each consisting of one or two PDT molecules connecting two gold nanoclusters. We formulate a perturbative theory of inelastic tunneling through molecules bridging metal contacts in terms of elastic transmission amplitudes, and use this theory to calculate the inelastic tunneling spectra of the gold-PDT-gold extended molecules. We consider PDT molecules with both trans and gauche conformations bound to the gold clusters at top, bridge and hollow bonding sites. Comparing our results with the experimental data of Hihath et al. [Nano Lett. 8, 1673 (2008)], we identify the most frequently realized conformation in the experiment as that of trans molecules top-site bonded to both electrodes. We find the switching from the 42 meV vibrational mode to the 46 meV mode observed in the experiment to be due to the transition of trans molecules from mixed top-bridge to pure top-site bonding geometries. Our results also indicate that gauche molecular conformations and hollow site bonding did not contribute significantly to the experimental inelastic tunneling spectra. For pairs of PDT molecules connecting the gold electrodes in parallel we find total elastic conductances close to twice those of single molecules bridging the contacts with similar bonding conformations and small splittings of the vibrational mode energies for the modes that are the most sensitive to the molecule-electrode bonding geometries.Comment: 14 pages, 8 figures, 1 table. arXiv admin note: significant text overlap with arXiv:1103.2378; http://jcp.aip.org/resource/1/jcpsa6/v136/i1/p014703_s

    Optimization of double drive pulse pumping in Ne-like Ge x-ray lasers

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    Pumping of the Ne-like Ge x-ray laser with two 100 ps duration pulses (a prepulse and main pulse) is investigated using a fluid and atomic physics code coupled to a 3D ray tracing postprocessor code. The modeling predicts the optimum ratio of the irradiance of the two pulses for the maximum x-ray laser output resulting from the balance between the relative lower electron density gradients and wider gain region which is produced with a larger prepulse and the higher peak gain coefficients produced with a small prepulse. With a longer pulse interval between prepulse and main pulse, a relatively lower optimum pulse ratio is found. The threshold irradiance of the main driving pulse with a prepulse required to make an order of magnitude enhancement of laser output compared to irradiation without a prepulse is also found at 3-4x10(13) W/cm(2) for Ne-like Ge. (C) 1998 American Institute of Physics

    The effect of supersymmetric CP phases on Chargino-Pair Production via Drell-Yan Process at the LHC

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    We compute the rates for pp annihilation into chargino-pairs via Drell-Yan process taking into account the effects of supersymmetric soft phases, at proton-proton collider. In particular, the phase of the mu parameter gains direct accessibility via the production of dissimilar charginos. The phases of the trilinear soft masses do not have a significant effect on the cross sections.Comment: 24 pages, 7 figure

    Distribution of some elements in Veronica scutellata L. from Bolu,Turkey: soil-plant interactions

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    Veronica scutellata L. occurs in moist and wet habitats, such as ponds, marshes and other wetlands. This study was conducted on this species to examine its mineral element uptake status in terms of interactions between soil and plant. Experimental materials were taken from the Southern coast of Black Sea at coordinates 40º36’N and 31º16’E at an altitude of 1400 m above sea level from Bolu – Turkey; using standard methods and plant (root, stem and leaf parts) and soil mineral element measurements (Al, B, Ca, Cu, Fe, K, Mg, Mn, Na, Ni and Zn) were done. During the study, ICP-OES was employed for the measurement of mineral elements. It was observed that considerable amounts of B, Ca, K, Mg, Mn, Na and Zn are accumulated by the plant

    Relaxation of the Dynamical Gluino Phase and Unambiguous Electric Dipole Moments

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    We propose a new axionic solution of the strong CP problem with a Peccei-Quinn mechanism using the gluino rather than quarks. The spontaneous breaking of this new global U(1) at 10^{11} GeV also generates the supersymmetry breaking scale of 1 TeV (solving the so-called \mu problem at the same time) and results in the MSSM (Minimal Supersymmetric Standard Model) with R parity conservation. In this framework, electric dipole moments become calculable without ambiguity.Comment: Typos corrected and a footnote added, 10 p

    Experiments and Simulations of short-pulse laser-pumped extreme ultraviolet lasers

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    Recent experimental work on the development of extreme ultraviolet lasers undertaken using as the pumping source the VULCAN laser at the Rutherford Appleton Laboratory is compared to detailed simulations. It is shown that short duration (similar topicosecond) pumping can produce X-ray laser pulses of a few picosecond duration and that measurement of the emission from the plasma can give an estimate of the duration of the gain coefficient. The Ehybrid fluid and atomic physics code developed at the University of York is used to simulate X-ray laser gain and plasma emission. Two postprocessors to the Ehybrid code are utilized: 1) to raytrace the X-ray laser beam amplification and refraction and 2) to calculate the radiation emission in the kiloelectronvolt photon energy range. The raytracing and spectral simulations are compared, respectively, to measured X-ray laser output and the output of two diagnostics recording transverse X-ray emission. The pumping laser energy absorbed in the plasma is examined by comparing the simulations to experimental results. It is shown that at high pumping irradiance (>10(15) Wcm(-2)), fast electrons are produced by parametric processes in the preformed long scale-length plasmas. These fast electrons do not pump the population inversion and so pumping efficiency is reduced at high irradiance

    Determination of the inhibitory effects of microdiets used in routine commercial feeding protocols on protease activities of Argyrosomus regius (Asso, 1801) larva

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    The aim of this study was to determine the inhibitory effects of feed ingredients on protease activities of Argyrosomus regius larvae using in vitro techniques. A. regius larvae fed on a commercial feeding procedure were sampled thirteen times, during the sampling period (from 3 to 32 days after hatching (DAH)). The differences observed in protease activities of meagre larvae during the sampling period were statistically significant (p<0.05). The lowest and highest protease activities of meagre larvae were 5.95±0.6 U/mg protein (15 DAH) and 211.21±12.56 U/mg protein (7 DAH), respectively. The fluctuations observed in protease activities of A. regius larvae were between 10 DAH and 32 DAH. Commercial diets such as Orange Start-S (100-200µ), Orange Start-L (200-300µ), Orange Nurse-XS (300-500µ), Orange Grow-S (300-500µ) and Orange Grow-L (500-800µ) caused the inhibitions on protease activities in meagre larvae to range from 16 to 32 DAH. The results point to the inadequacy of commercial diets such as Orange Grow-S, Orange Grow-L and suitability of Orange Start-S, Orange Start-L, Orange Nurse-XS for feeding meagre larvae during the weaning stage. For the mass production of quality juveniles, future studies should take into account the inhibitory effects of commercial diets and feed ingredients before the manufacturing process. A similar approach may be used to determine the most suitable commercial diets for use during the weaning stages of marine fish larvae to obtain the best growth performance and survival
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