2,333 research outputs found
Gauge and Averaging in Gravitational Self-force
A difficulty with previous treatments of the gravitational self-force is that
an explicit formula for the force is available only in a particular gauge
(Lorenz gauge), where the force in other gauges must be found through a
transformation law once the Lorenz gauge force is known. For a class of gauges
satisfying a ``parity condition'' ensuring that the Hamiltonian center of mass
of the particle is well-defined, I show that the gravitational self-force is
always given by the angle-average of the bare gravitational force. To derive
this result I replace the computational strategy of previous work with a new
approach, wherein the form of the force is first fixed up to a gauge-invariant
piece by simple manipulations, and then that piece is determined by working in
a gauge designed specifically to simplify the computation. This offers
significant computational savings over the Lorenz gauge, since the Hadamard
expansion is avoided entirely and the metric perturbation takes a very simple
form. I also show that the rest mass of the particle does not evolve due to
first-order self-force effects. Finally, I consider the ``mode sum
regularization'' scheme for computing the self-force in black hole background
spacetimes, and use the angle-average form of the force to show that the same
mode-by-mode subtraction may be performed in all parity-regular gauges. It
appears plausible that suitably modified versions of the Regge-Wheeler and
radiation gauges (convenient to Schwarzschild and Kerr, respectively) are in
this class
Honey Bees In and Around Buildings
5 pp., 7 photosWasps are more often a problem around homes than honey bees, but bees do sometimes swarm or build nests near homes, or even in the walls of homes and other structures. This publication explains how to identify and manage foraging bees, swarms and colonies. Specific techniques for controlling bees that build colonies in buildings are explained in detail
The sentiment analysis of tweets as a new tool to measure public perception of male erectile and ejaculatory dysfunctions
Twitter is a social network based on "tweets," short messages of up to 280 characters. Social media has been investigated in health care research to ascertain positive or negative feelings associated with several conditions but never in sexual medicin
Automatic Synchronization of Multi-User Photo Galleries
In this paper we address the issue of photo galleries synchronization, where
pictures related to the same event are collected by different users. Existing
solutions to address the problem are usually based on unrealistic assumptions,
like time consistency across photo galleries, and often heavily rely on
heuristics, limiting therefore the applicability to real-world scenarios. We
propose a solution that achieves better generalization performance for the
synchronization task compared to the available literature. The method is
characterized by three stages: at first, deep convolutional neural network
features are used to assess the visual similarity among the photos; then, pairs
of similar photos are detected across different galleries and used to construct
a graph; eventually, a probabilistic graphical model is used to estimate the
temporal offset of each pair of galleries, by traversing the minimum spanning
tree extracted from this graph. The experimental evaluation is conducted on
four publicly available datasets covering different types of events,
demonstrating the strength of our proposed method. A thorough discussion of the
obtained results is provided for a critical assessment of the quality in
synchronization.Comment: ACCEPTED to IEEE Transactions on Multimedi
Relationship between hyperuricemia with deposition and sexual dysfunction in males and females
Purpose The association between gout, the most common crystal arthropathy, and sexual dysfunctions has often been investigated by studies in the last decades. Despite the presence of shared risk factors and comorbidities and the possible effects on sexual health of long-term gout complications, awareness of this association is severely lacking and the pathogenetic mechanisms have only partially been identified. In the present review, we aimed to investigate the current evidence regarding the potential mechanisms linking sexual dysfunctions and gout. Methods A comprehensive literature search within PubMed was performed to provide a summary of currently available evidence regarding the association between gout and sexual dysfunctions. Results Gout and sexual dysfunctions share several risk factors, including diabesity, chronic kidney disease, hypertension, metabolic syndrome, and peripheral vascular disease. Gout flares triggered by intense inflammatory responses feature severe pain and disability, resulting in worse sexual function, and some, but not all, treatments can also impair sexual health. Long-term gout complications can result in persistent pain and disability due to joint deformity, fractures, or nerve compression, with negative bearing on sexual function. The presence of low-grade inflammation impairs both sex steroids synthesis and endothelial function, further advancing sexual dysfunctions. The psychological burden of gout is another issue negatively affecting sexual health. Conclusions According to currently available evidence, several biological and psychological mechanisms link sexual dysfunctions and gout. Addressing risk factors and providing adequate treatment could potentially have beneficial effects on both conditions. Appropriate clinical evaluation and multidisciplinary approach are recommended to improve patient care
On-site number statistics of ultracold lattice bosons
We study on-site occupation number fluctuations in a system of interacting
bosons in an optical lattice. The ground-state distribution is obtained
analytically in the limiting cases of strong and weak interaction, and by means
of exact Monte Carlo simulations in the strongly correlated regime. As the
interaction is increased, the distribution evolves from Poissonian in the
non-interacting gas to a sharply peaked distribution in the Mott-insulator (MI)
regime. In the special case of large occupation numbers, we demonstrate
analytically and check numerically that there exists a wide interval of
interaction strength, in which the on-site number fluctuations remain Gaussian
and are gradually squeezed until they are of order unity near the superfluid
(SF)-MI transition. Recently, the on-site number statistics were studied
experimentally in a wide range of lattice potential depths [Phys. Rev. Lett.
\textbf{96}, 090401 (2006)]. In our simulations, we are able to directly
reproduce experimental conditions using temperature as the only free parameter.
Pronounced temperature dependence suggests that measurements of on-site atom
number fluctuations can be employed as a reliable method of thermometry in both
SF and MI regimes.Comment: 9 pages, 4 figure
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