1,735 research outputs found
Correlation functions of the energy-momentum tensor in SU(2) gauge theory at finite temperature
We calculate correlation functions of the energy-momentum tensor in the
vicinity of the deconfinement phase transition of (3+1)-dimensional SU(2) gauge
theory and discuss their critical behavior in the vicinity of the second order
deconfinement transition. We show that correlation functions of the trace of
the energy momentum tensor diverge uniformly at the critical point in
proportion to the specific heat singularity. Correlation functions of the
pressure, on the other hand, stay finite at the critical point. We discuss the
consequences of these findings for the analysis of transport coefficients, in
particular the bulk viscosity, in the vicinity of a second order phase
transition point.Comment: 24 pages, 6 figure
Synchronized oscillations and acoustic fluidization in confined granular materials
According to the acoustic fluidization hypothesis, elastic waves at a
characteristic frequency form inside seismic faults even in the absence of an
external perturbation. These waves are able to generate a normal stress which
contrasts the confining pressure and promotes failure. Here, we study the
mechanisms responsible for this wave activation via numerical simulations of a
granular fault model. We observe the particles belonging to the percolating
backbone, which sustains the stress, to perform synchronized oscillations over
ellipticlike trajectories in the fault plane. These oscillations occur at the
characteristic frequency of acoustic fluidization. As the applied shear stress
increases, these oscillations become perpendicular to the fault plane just
before the system fails, opposing the confining pressure, consistently with the
acoustic fluidization scenario. The same change of orientation can be induced
by external perturbations at the acoustic fluidization frequency
Public awareness and knowledge of herpes labialis
Between 20% and 40% of the population is estimated to suffer from episodes of recurrent herpes labialis, although few reports in the literature have addressed the public awareness of this infection in the general population. The aims of this study were to determine the existing level of awareness and knowledge of this disease and to assess the source of this knowledge, the ability of the public to recognize the characteristics of the disease and the behavior of patients with clinical cases of disease manifestation. To this end, 2,000 individuals (961 male and 1,039 female) of 14 years of age and older were surveyed using the ECOcapi system [Eurisko Consumer Omnibus-CAPI (computer-assisted personal interviewing) version]. Eighty-nine percent of those surveyed had some knowledge of herpes labialis; 92% were able to refer to at least one symptom of herpes labialis, 91% were able to identify correctly his infection from pictures, and 45% had experienced personally at least one episode of herpes labialis infection. The majority of the individuals suffering from herpes labialis self-medicated using a topical therapy. Women were found to be affected more commonly by herpes labialis than men [OR 1.42 (1.18-1.70)], and women were also more likely to recognize the disease [OR 1.65 (1.30-2.08)] and to seek medical advice for the condition [OR 1.38 (1.12-1.70)]. In conclusion, herpes labialis is a common and well-known condition, and it is often self-diagnosed correctly, as the prodromal phase and the use of self-medication are very common. J. Med. Virol. © 2011 Wiley Periodicals, Inc
A nanostructured look of collagen apatite porosity into human mineralized collagen fibril
Bone tissue is a hierarchical material characterized at nanoscale by the mineralized collagen fibril, a recurring structure mainly composed of apatite minerals, collagen and water. Bone nanostructure has a fundamental role in determining the mechanical behavior of the tissue and its mass transport properties. Diffusion phenomenon allows to maintain an adequate supply of metabolites in the mechanisms of bone remodeling, adaptation and repair. Several analytical and computational models have been developed to analyze and predict bone tissue behavior. However, the fine replication of the natural tissue still represents a challenge. Insights on the structural organization at nanoscale and on the influence of apatite mineral crystals on the diffusion coefficient lead to outline the functional conditions for the development of biomimetic strategies for bone tissue engineering. Thorough understanding of bone nanostructure is essential to improve longevity of bioscaffolds and to decrease the risk of failure by controlling their mechanical and biological performance
Nambu-Jona-Lasinio model with Wilson fermions
12 pages, 5 figuresWe present a lattice study of a Nambu Jona-Lasinio (NJL) model using Wilson fermions. Four fermion interactions are a natural part of several extensions of the Standard Model, appearing as a low energy description of a more fundamental theory. In models of dynamical electroweak symmetry breaking they are used to endow the Standard Model fermions with masses. In infrared conformal models these interaction, when sufficiently strong, can alter the dynamics of the fixed point, turning the theory into a (near) conformal model with desirable features for model building. As a first step toward the nonperturbative study of these models, we study the phase space of the ungauged NJL model
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Insurance Between Firms: The Role of Internal Labor Markets
We investigate how Internal Labor Markets (ILMs) allow organizations to accommodate shocks calling for costly labor adjustments. Using data on workers' mobility within French business groups, we find that adverse shocks affecting affiliated firms boost the proportion of workers redeployed to other group units rather than external firms. This effect is stronger when labor regulations are stricter and destination-firms are more efficient or enjoy better growth opportunities. Affiliated firms hit by positive shocks rely on the ILM for new hires, especially high-skilled workers. Overall, ILMs emerge as a co-insurance mechanism within organizations, providing job stability to employees as a by-product
Wilson Fermions with Four Fermion Interactions
Contribution to proceedings of the 33rd International Symposium on Lattice Field Theory (Lattice 2015), 14-18 July 2015, Kobe, JapanWe present a lattice study of a four fermion theory, known as Nambu Jona-Lasinio (NJL) theory, via Wilson fermions. Four fermion interactions naturally occur in several extensions of the Standard Model as a low energy parameterisation of a more fundamental theory. In models of dynamical electroweak symmetry breaking these operators, at an effective level, are used to endow the Standard Model fermions with masses. Furthermore these operators, when sufficiently strong, can drastically modify the fundamental composite dynamics by, for example, turning a strongly coupled infrared conformal theory into a (near) conformal one with desirable features for model building. As first step, we study spontaneous chiral symmetry breaking for the lattice version of the NJL model
Template Composite Dark Matter : SU(2) gauge theory with 2 fundamental flavours
Contribution to proceedings of the 33rd International Symposium on Lattice Field Theory (Lattice 2015), 14-18 July 2015, Kobe, JapanWe present a non perturbative study of SU(2) gauge theory with two fundamental Dirac flavours. We discuss how the model can be used as a template for composite Dark Matter (DM). We estimate one particular interaction of the DM candidate with the Standard Model : the interaction through photon exchange computing the electric polarizability of the DM candidate. Finally, we briefly discuss the viability of the model given the present experimental constraints
No evidence of family history as a risk factor for herpes zoster in patients with post-herpetic neuralgia
Little is known about reactivation of latent varicella zoster virus as herpes zoster in individuals with no underlying immunosuppression. Risk factors include age, sex, ethnicity, exogenous boosting of immunity from varicella contacts, underlying cell-mediated immune disorders, mechanical trauma, psychological stress, and immunotoxin exposure. An association between herpes zoster and family history of zoster has been proposed. A case-control study involving patients affected by post-herpetic neuralgia, which usually follows more severe acute herpes zoster, was performed. The patients with post-herpetic neuralgia were enrolled at the Pain Clinic of the Policlinico Tor Vergata in Rome, Italy, within 1 year from the onset of acute zoster. The controls matched for sex and age were chosen among healthy subjects without a history of herpes zoster presenting at the Internal Medicine Outpatient Clinic for hypertension in the same time period. All the participants in the study gave informed consent and were interviewed by medically trained and blinded investigators using a questionnaire. Similar proportions of the patients and the controls reported a family history of herpes zoster irrespective of the degree of relationship, i.e., 17.4% and 18.2%, respectively, by analyzing only the first-degree relatives [RR 1.03 (CI 95%: 0.78-1.37)], and 28.4% and 29.6%, respectively, by analyzing the total number of relatives [RR 1.03 (CI 95%: 0.81-1.31)]. Further and larger prospective cohort studies are needed to ascertain whether a family history of herpes zoster is really an independent predictor of zoster in different geographical settings
Clinical and psychosocial correlates of post-herpetic neuralgia
Post-herpetic neuralgia is the most challenging and debilitating complication of herpes zoster in the immunocompetent host. Because the effect of treatment is disappointing once the syndrome has developed, it is important to know which factors predict post-herpetic neuralgia occurrence to facilitate selection of herpes zoster patients with a higher risk of developing neuralgia and undertake preventative strategies. The present study aimed at identifying demographic, clinical and psychosocial correlates of post-herpetic neuralgia in a sample of 219 immunocompetent patients, who were examined by dermatologists in private practice in Italy and who completed a questionnaire designed to evaluate their clinical and psychosocial profile at the time of clinical diagnosis of herpes zoster and at a follow-up visit 6 months later. In a univariate analysis, post-herpetic neuralgia was associated significantly with older age, longer duration of prodromal pain, greater acute pain intensity, greater extent of rash, presence of abnormal sensations and use of systemic antiviral therapy. Compared to the values at herpes zoster onset, at the follow-up visit patients with post-herpetic neuralgia presented with similar high mean scores of pain intensity, anxiety and depression and greatly reduced quality of life, whereas patients without neuralgia presented with improved scores. In a multivariate model, older age, greater acute pain intensity, greater extent of rash and longer duration of prodromal pain were independently associated with post-herpetic neuralgia. The results of this study may help physicians to identify patients with a higher risk of developing post-herpetic neuralgia and undertaking preventative strategies
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