2,923 research outputs found
Spherical Casimir energies and Dedekind sums
Casimir energies on space-times having general lens spaces as their spatial
sections are shown to be given in terms of generalised Dedekind sums related to
Zagier's. These are evaluated explicitly in certain cases as functions of the
order of the lens space. An easily implemented recursion approach is used.Comment: 18 pages, 2 figures, v2:typos corrected, inessential equation in
Discussion altered. v3:typos corrected, 1 reference and comments added.
v4:typos corrected. Ancillary results added in an appendi
Approximating Tverberg Points in Linear Time for Any Fixed Dimension
Let P be a d-dimensional n-point set. A Tverberg-partition of P is a
partition of P into r sets P_1, ..., P_r such that the convex hulls conv(P_1),
..., conv(P_r) have non-empty intersection. A point in the intersection of the
conv(P_i)'s is called a Tverberg point of depth r for P. A classic result by
Tverberg implies that there always exists a Tverberg partition of size n/(d+1),
but it is not known how to find such a partition in polynomial time. Therefore,
approximate solutions are of interest.
We describe a deterministic algorithm that finds a Tverberg partition of size
n/4(d+1)^3 in time d^{O(log d)} n. This means that for every fixed dimension we
can compute an approximate Tverberg point (and hence also an approximate
centerpoint) in linear time. Our algorithm is obtained by combining a novel
lifting approach with a recent result by Miller and Sheehy (2010).Comment: 14 pages, 2 figures. A preliminary version appeared in SoCG 2012.
This version removes an incorrect example at the end of Section 3.
Facile method for trimethylsilylation of alcohols using hexamethyldisilazane and ammonium thiocyanate under neutral conditions
A highly efficient method for trimethylsilylation of primary, secondary, tertiary, allylic, and a variety of sugar-derived alcohols using hexamethyldisilazane in the presence of a catalytic amount of ammonium thiocyanate under neutral conditions is reported
Obesity: Pathogenesis and emerging targets for drug development
Obesity leads to premature death and impairs quality of life. In general, weight loss is responsible and reduced the risk of cardiovascular disease that is associated with obesity. One of the recognized and well establishment treatment option for weight loss i.e. pharmacotherapy where cardiovascular safety issues with some previous weight loss drugs raise concerns for newly approved pharmacotherapies. Previously, number of anti-obesity drugs that are already withdrawn from the market because of adverse side effects. In the present study, our group focused only on antiobesity drugs that are currently under investigation and also understand its pathogenesis.ĂÂ Although lot of anti-obesity drugs are in the pipeline, the process for getting such type of drugs to be marketed has recently proven so difficult
Determinants on lens spaces and cyclotomic units
The Laplacian functional determinants for conformal scalars and coexact
one-forms are evaluated in closed form on inhomogeneous lens spaces of certain
orders, including all odd primes when the essential part of the expression is
given, formally as a cyclotomic unitComment: 18 pages, 1 figur
Mental illness, poverty and stigma in India: a case-control study
OBJECTIVE: To assess the effect of experienced stigma on depth of multidimensional poverty of persons with severe mental illness (PSMI) in Delhi, India, controlling for gender, age and caste.
DESIGN: Matching case (hospital)âcontrol (population) study.
SETTING: University Hospital (cases) and National Capital Region (controls), India.
PARTICIPANTS: A caseâcontrol study was conducted from November 2011 to June 2012. 647 cases diagnosed with schizophrenia or affective disorders were recruited and 647 individuals of same age, sex and location of residence were matched as controls at a ratio of 1:2:1. Individuals who refused consent or provided incomplete interview were excluded.
MAIN OUTCOME MEASURES: Higher risk of poverty due to stigma among PSMI.
RESULTS: 38.5% of PSMI compared with 22.2% of controls were found poor on six dimensions or more. The difference in multidimensional poverty index was 69% between groups with employment and income of the main contributors. Multidimensional poverty was strongly associated with stigma (OR 2.60, 95% CI 1.27 to 5.31), scheduled castes/scheduled tribes/other backward castes (2.39, 1.39 to 4.08), mental illness (2.07, 1.25 to 3.41) and female gender (1.87, 1.36 to 2.58). A significant interaction between stigma, mental illness and gender or caste indicates female PSMI or PSMI from âlower castesâ were more likely to be poor due to stigma than male controls (p<0.001) or controls from other castes (p<0.001).
CONCLUSIONS: Public stigma and multidimensional poverty linked to SMI are pervasive and intertwined. In particular for low caste and women, it is a strong predictor of poverty. Exclusion from employment linked to negative attitudes and lack of income are the highest contributors to multidimensional poverty, increasing the burden for the family. Mental health professionals need to be aware of and address these issues
An Intrusion Detection System Algorithm for Defending MANET against the DDoS Attacks.
Mobile ad hoc network (MANET) is rapidly deployable, self configuring network able to communicate with each other without the aid of any centralized system. There is no need for existing infrastructure base network. In MANET Wireless medium is radio frequencies and nodes are mobile, topology can be very dynamically. Nodes must be able to relay traffic since communicating nodes might be out of range. A MANET can be a standalone network or it can be connected to external networks like internet. Multihop operation of MANET requires a routing mechanism designed for mobile nodes are internet access mechanisms, self configuring networks requires an address allocation mechanism, mechanism to detect and act on, merging of existing networks and security mechanisms. As we know that there is no any centralized system so routing is done by node itself. Due to its mobility and self routing capability nature, there are many weaknesses in its security
Spherical Universe topology and the Casimir effect
The mode problem on the factored 3--sphere is applied to field theory
calculations for massless fields of spin 0, 1/2 and 1. The degeneracies on the
factors, including lens spaces, are neatly derived in a geometric fashion.
Vacuum energies are expressed in terms of the polyhedral degrees and equivalent
expressions given using the cyclic decomposition of the covering group. Scalar
functional determinants are calculated and the spectral asymmetry function
treated by the same approach with explicit forms on one-sided lens spaces.Comment: 33 pages, 1 figure. Typos corrected and one reference adde
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