1,106 research outputs found
Duality for MultiobjectiveB-vex Programming Involvingn-Set Functions
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
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
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
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 and superconductors
Motivated by recent discoveries of novel superconductors such as
NaCoOHO and SrRuO, we analysize features of
quasi-particle scattering due to impurities and interfaces for possible gapful
and 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
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
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=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
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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