Bulk Viscosity of Magnetized Neutron Star Matter

We study the effect of magnetic field on the bulk viscosity of nuclear matter in neutron stars. We employ the framework of relativistic mean field theory to observe the dense nuclear matter in neutron stars. The effects are first studied for the case when the magnetic field does not exceed the critical value to confine the electrons to the lowest Landau levels. We then consider the case of intense magnetic field to evaluate viscosity for the URCA processes and show that the inequality $p_{F}(e)+p_{F}(p)\geq p_{F}(n)$ is no longer required to be satisfied for the URCA processes to proceed.Comment: Latex 2e file with four postscripts figure

Popliteal-crural bypass through the posterior approach with lesser saphenous vein for limb salvage

AbstractPurpose: A review of popliteal-crural bypasses via the posterior approach was done to evaluate the results of this technique. Methods: During a period of 36 months, 21 patients with limb-threatening ischemia underwent 21 popliteal-crural bypasses via the posterior approach in the prone position with reversed lesser saphenous vein. All patients had limb-threatening ischemia, with rest pain in five patients, ulceration in nine patients, and gangrene in seven patients. Diabetes mellitus was present in 17 patients. Results: The inflow site was the supragenicular popliteal artery in 12 patients and the infragenicular popliteal artery in nine patients. The outflow sites were the tibioperoneal trunk in five patients, the posterior tibial artery in six patients, the peroneal artery in eight patients, and the anterior tibial artery in two patients. Of the seven patients with gangrene, three patients underwent transmetatarsal amputation and four underwent toe amputation. The limb salvage rate for the entire group was 100% at 24 months. No early graft failures were seen, and the 12-month and 24-month primary graft patency rates were 89% and 77%, respectively, with life-table analysis. The primary assisted patency rate was 95% at 12 and 24 months. Patency was determined with duplex scan graft surveillance. Conclusion: The posterior approach to popliteal-distal bypass is an acceptable alternative to traditional bypass procedure with excellent early patency and limb salvage results. The approach has the advantage of better utilization of lesser saphenous vein and easier operative exposure in patients with short segment infrapopliteal occlusive disease. (J Vasc Surg 2002;36:708-12.

Evolution of Coordination in Social Networks: A Numerical Study

Coordination games are important to explain efficient and desirable social behavior. Here we study these games by extensive numerical simulation on networked social structures using an evolutionary approach. We show that local network effects may promote selection of efficient equilibria in both pure and general coordination games and may explain social polarization. These results are put into perspective with respect to known theoretical results. The main insight we obtain is that clustering, and especially community structure in social networks has a positive role in promoting socially efficient outcomes.Comment: preprint submitted to IJMP

Neutrino opacity in magnetised hot and dense nuclear matter

We study the neutrino interaction rates in hot matter at high densities in the presence of uniform magnetic field. The neutrino cross-sections involving both the charged current absorption and neutral current scattering reactions on baryons and leptons have been considered. We have in particular considered the interesting case when the magnetic field is strong enough to completely polarise the protons and electrons in supernovae and neutron stars. The opacity in such a situation is considerably modified and the cross-section develops anisotropy. This has implications for phenomenon invoked in the literature to explain the observed pulsar kicks.Comment: 22 latex pages and 7 postscript figure

Land Surface Characterization for Identification and Assessment of Potential Grazing Lands in Arid Western Rajasthan, India

Grazing lands (non-arable terrestrial ecosystems) play a vital role in the rural economy and environmental conservation. Modern tools in which, GIS, GPS and satellite remote sensing play vital role in the assessment, characterization and management of grazinglands (Paul et al., 2010). The present study aims to assess the physical conditions and distribution pattern of permanent pastures and other grazing lands in arid Rajasthan using remote sensing and GIS techniques. Though grazing lands do occur in a number of habitats, the study has focused on those sites which have water resources for its rational utilization for pasture/grassland development. Rapid advances in the areas of Remote Sensing, Earth Observations systems, data processing techniques and applications have facilitated users for a better understanding of terrain. One of the recent trends in remote sensing is its application in the extraction of terrain related parameters using large scale mapping and DEM generation. GIS and IRS data are used in inventory, assessment, characterization and management of grazinglands and estimation of forage production & supply-demand balance sheets (Singh et al., 1997)

Phototropism: at the crossroads of light-signaling pathways.

Phototropism enables plants to orient growth towards the direction of light and thereby maximizes photosynthesis in low-light environments. In angiosperms, blue-light photoreceptors called phototropins are primarily involved in sensing the direction of light. Phytochromes and cryptochromes (sensing red/far-red and blue light, respectively) also modulate asymmetric hypocotyl growth, leading to phototropism. Interactions between different light-signaling pathways regulating phototropism occur in cryptogams and angiosperms. In this review, we focus on the molecular mechanisms underlying the co-action between photosensory systems in the regulation of hypocotyl phototropism in Arabidopsis thaliana. Recent studies have shown that phytochromes and cryptochromes enhance phototropism by controlling the expression of important regulators of phototropin signaling. In addition, phytochromes may also regulate growth towards light via direct interaction with the phototropins

Composite Structures Damage Tolerance Analysis Methodologies

This report presents the results of a literature review as part of the development of composite hardware fracture control guidelines funded by NASA Engineering and Safety Center (NESC) under contract NNL04AA09B. The objectives of the overall development tasks are to provide a broad information and database to the designers, analysts, and testing personnel who are engaged in space flight hardware production

Entanglement between more than two hundred macroscopic atomic ensembles in a solid

We create a multi-partite entangled state by storing a single photon in a crystal that contains many large atomic ensembles with distinct resonance frequencies. The photon is re-emitted at a well-defined time due to an interference effect analogous to multi-slit diffraction. We derive a lower bound for the number of entangled ensembles based on the contrast of the interference and the single-photon character of the input, and we experimentally demonstrate entanglement between over two hundred ensembles, each containing a billion atoms. In addition, we illustrate the fact that each individual ensemble contains further entanglement. Our results are the first demonstration of entanglement between many macroscopic systems in a solid and open the door to creating even more complex entangled states.Comment: 10 pages, 8 figures; see also parallel submission by Frowis et a

The interpretation of the field angle dependence of the critical current in defect-engineered superconductors

We apply the vortex path model of critical currents to a comprehensive analysis of contemporary data on defect-engineered superconductors, showing that it provides a consistent and detailed interpretation of the experimental data for a diverse range of materials. We address the question of whether electron mass anisotropy plays a role of any consequence in determining the form of this data and conclude that it does not. By abandoning this false interpretation of the data, we are able to make significant progress in understanding the real origin of the observed behavior. In particular, we are able to explain a number of common features in the data including shoulders at intermediate angles, a uniform response over a wide angular range and the greater discrimination between individual defect populations at higher fields. We also correct several misconceptions including the idea that a peak in the angular dependence of the critical current is a necessary signature of strong correlated pinning, and conversely that the existence of such a peak implies the existence of correlated pinning aligned to the particular direction. The consistency of the vortex path model with the principle of maximum entropy is introduced.Comment: 14 pages, 7 figure