1,106 research outputs found

    Duality for MultiobjectiveB-vex Programming Involvingn-Set Functions

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    AbstractIn the present paper we consider a class of multiobjectiveB-vex programming problems involving differentiableB-vexn-set functions and establish duality results in terms of properly efficient solutions. Further, we relate the problem to a certain saddle point of a Lagrangian and show multiobjective fractional program as a special case of the main problem

    Hydrological And hydraulic modelling for the restoration and management of Loktak Lake, Northeast India

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    Loktak Lake is an internationally important wetland in northeast India that provides valuable goods and services to local communities as well as supporting high biodiversity. Over the last three decades ecological modifications have occurred, most notably due to the construction and operation of the Ithai Barrage. The focus on maximising hydropower generation increased mean lake water levels and reduced their annual variability. This thesis synthesises hydrometeorological and related data for the lake and its catchment. Data are employed in coupled hydrological / hydraulic catchment models (MIKE SHE / MIKE 11) of three gauged sub-catchments, which are calibrated / validated using observed discharges. Results are used to estimate ungauged sub-catchment flows. Catchment model results are combined with meteorological data and current abstractions within a water balance model which successfully simulates observed lake water levels. A series of barrage operation options are developed using the water balance model which prioritise the requirements of major stakeholders (hydropower, agriculture, and the lake ecosystem). A final option is developed, which shows that it is possible to balance the demands of these stakeholders. The implications of climate change are assessed by forcing meteorological inputs to the catchment and water balance models based upon a number of climate scenarios. In the majority of these scenarios, river inflows increase resulting in higher lake water levels that could further exacerbate ecological degradation of the lake as well as enhancing flooding of lakeside communities. The elevated water levels may permit additional irrigation abstractions however existing infrastructure limits increases in hydropower generation. The sustainability of the barrage operation options in the face of climate change is assessed. Results suggest that climate change is likely to limit the ability of barrage management to satisfy hydropower and agricultural demands whilst at the same time establishing a more ecologically appropriate lake water level regime

    Association of History of Injection Drug Use with External Cause-Related Mortality Among Persons Linked to HIV Care in an Urban Clinic, 2001–2015

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    High mortality rates among persons with HIV with a history of injection drug use (PWID) are thought to be driven in part by higher rates of external cause-related mortality. We followed 4796 persons aged 18–70 engaged in continuity HIV care from 2001 to 2015 until death or administrative censoring. We compared cause-specific (csHR) and subdistribution hazards (sdHR) of death due to external causes among PWID and persons who acquired their HIV infection through other routes (non-IDU). We standardized estimates on age, sex, race, and HIV-related health status. The standardized csHR for external cause-related death was 3.57 (95% CI 2.39, 5.33), and the sdHR was 3.14 (95% CI 2.16, 4.55). The majority of external cause-related deaths were overdose-related and standardized sdHR was 4.02 (95% CI 2.40, 6.72). Absolute rate of suicide was low but the csHR for PWID compared to non-IDU was most elevated for suicide (6.50, 95% CI 1.51, 28.03). HIV-infected PWID are at a disproportionately increased risk of death due to external causes, particularly overdose and suicide

    Penrose limits of Lie Branes and a Nappi--Witten braneworld

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    Departing from the observation that the Penrose limit of AdS_3 x S^3 is a group contraction in the sense of Inonu and Wigner, we explore the relation between the symmetric D-branes of AdS_3 x S^3 and those of its Penrose limit, a six-dimensional symmetric plane wave analogous to the four-dimensional Nappi--Witten spacetime. Both backgrounds are Lie groups admitting bi-invariant lorentzian metrics and symmetric D-branes wrap their (twisted) conjugacy classes. We determine the (twisted and untwisted) symmetric D-branes in the plane wave background and we prove the existence of a space-filling D5-brane and, separately, of a foliation by D3-branes with the geometry of the Nappi--Witten spacetime which can be understood as the Penrose limit of the AdS_2 x S^2 D3-brane in AdS_3 x S^3. Parenthetically we also derive a simple criterion for a symmetric plane wave to be isometric to a lorentzian Lie group. In particular we observe that the maximally supersymmetric plane wave in IIB string theory is isometric to a lorentzian Lie group, whereas the one in M-theory is not.Comment: 21 pages (v2: references added

    Impurity and interface bound states in dx2y2+idxyd_{x^2-y^2}+id_{xy} and px+ipyp_x+ip_y superconductors

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    Motivated by recent discoveries of novel superconductors such as Nax_xCoO2y_2\cdot yH2_2O and Sr2_2RuO4_4, we analysize features of quasi-particle scattering due to impurities and interfaces for possible gapful dx2y2+idxyd_{x^2-y^2}+id_{xy} and px+ipyp_x+ip_y Cooper pairing. A bound state appears near a local impurity, and a band of bound states form near an interface. We obtained analytically the bound state energy, and calculated the space and energy dependent local density of states resolvable by high-resolution scanning tunnelling microscopy. For comparison we also sketch results of impurity and surface states if the pairing is nodal p- or d-wave.Comment: 4 pages, 4 figure

    Heavy Metal Contamination of Food Crops: Transportation via Food Chain, Human Consumption, Toxicity and Management Strategies

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    Food security is a major concern that requires sustained advancement both statistically and on the basis of Qualitative assessment. In recent years, antagonistic impacts of unforeseen toxins have impacted the quality of crops and have created a burden on human lives. Heavy metals (e.g., Hg, As, Pb, Cd, and Cr) can affect humans, adding to dreariness and in severe cases even death. It additionally investigates the conceivable geological routes of heavy metals in the surrounding subsystems. The top-to-the-bottom conversation is additionally offered on physiological/atomic movement systems engaged with the take-up of metallic foreign substances inside food crops. At long last, the board procedures are proposed to recapture maintainability in soil–food subsystems. This paper reflects the contamination of the food crops with heavy metals, the way of transport of heavy metal to food crops, degree of toxicity after consumption and the strategies to maintain the problem

    Relativistic wave equations for interacting massive particles with arbitrary half-intreger spins

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    New formulation of relativistic wave equations (RWE) for massive particles with arbitrary half-integer spins s interacting with external electromagnetic fields are proposed. They are based on wave functions which are irreducible tensors of rank n(n (n=s-\frac12$) antisymmetric w.r.t. n pairs of indices, whose components are bispinors. The form of RWE is straightforward and free of inconsistencies associated with the other approaches to equations describing interacting higher spin particles

    Big Crunch Avoidance in k = 1 Semi-Classical Loop Quantum Cosmology

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    It is well known that a closed universe with a minimally coupled massive scalar field always collapses to a singularity unless the initial conditions are extremely fine tuned. We show that the corrections to the equations of motion for the massive scalar field, given by loop quantum gravity in high curvature regime, always lead to a bounce independently of the initial conditions. In contrast to the previous works in loop quantum cosmology, we note that the singularity can be avoided even at the semi-classical level of effective dynamical equations with non-perturbative quantum gravity modifications, without using a discrete quantum evolution.Comment: Minor changes, To appear in Physical Review
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