2,076 research outputs found
Critical Dynamics of a Vortex Loop Model for the Superconducting Transition
We calculate analytically the dynamic critical exponent measured in
Monte Carlo simulations for a vortex loop model of the superconducting
transition, and account for the simulation results. In the weak screening
limit, where magnetic fluctuations are neglected, the dynamic exponent is found
to be . In the perfect screening limit, . We relate
to the actual value of observable in experiments and find that , consistent with some experimental results
Children Attending Day Care Centers are a Year-round Reservoir of Gastrointestinal Viruses
Abstract Viral gastroenteritis causes high morbidity worldwide. In this study, stool samples from 179 children aged 0â6 years attending Danish day care centers were investigated for gastrointestinal viruses. Each child was observed for one year with submission of samples and questionnaires every two months. Adenovirus, norovirus, rotavirus, and sapovirus were detected in samples using real-time PCR. A total of 229 (33%) of the 688 samples collected tested positive for at least one virus. At the first sampling point, adenovirus was shed by 6%, norovirus genotype I by 3% and genotype II by 12%, rotavirus A by 9%, and sapovirus by 21% of the 142 children included in the risk factor analyses. Increasing age was identified as a protective factor against testing positive for gastrointestinal virus, whereas nausea during the previous two months was positively associated with testing positive. Odds of shedding adenovirus were 9.6 times higher among children treated with antibiotics within the previous two months than among children who were not. Gastrointestinal viruses were shed year-round and high viral loads were observed in samples from both symptomatic and asymptomatic children, suggesting children in day care as a reservoir and a possible source of spreading of viruses into the community
Capsaicin-sensitive cutaneous primary afferents convey electrically induced itch in humans
Specially designed transcutaneous electrical stimulation paradigms can be used to provoke experimental itch. However, it is unclear which primary afferent fibers are activated and whether they represent pathophysiologically relevant, C-fiber mediated itch. Since low-threshold mechano-receptors have recently been implicated in pruriception we aimed to characterize the peripheral primary afferent subpopulation conveying electrically evoked itch in humans (50 Hz stimulation, 100 Οs square pulses, stimulus-response function to graded stimulus intensity). In 10 healthy male volunteers a placebo-controlled, 24-h 8% topical capsaicin-induced defunctionalization of capsaicin-sensitive (transient receptor potential V1-positive, âTRPV1â+) cutaneous fibers was performed. Histaminergic itch (1% solution introduced by a prick test lancet) was provoked as a positive control condition. Capsaicin pretreatment induced profound loss of warmth and heat pain sensitivity (pain threshold and supra-threshold ratings) as assessed by quantitative sensory testing, indicative of efficient TRPV1-fiber defunctionalization (all outcomes: P 0.0001). The topical capsaicin robustly, and with similar efficaciousness, inhibited itch intensity evoked by electrical stimulation and histamine (â89 ¹ 4.1% and â78 ¹ 4.9%, respectively, both: P 0.0001 compared to the placebo patch area). The predominant primary afferent substrate for electrically evoked itch in humans, using the presently applied stimulation paradigm, is concluded to be capsaicin-sensitive polymodal C-fibers.FSW - Self-regulation models for health behavior and psychopathology - ou
Screening of Spherical Colloids beyond Mean Field -- A Local Density Functional Approach
We study the counterion distribution around a spherical macroion and its
osmotic pressure in the framework of the recently developed
Debye-H"uckel-Hole-Cavity (DHHC) theory. This is a local density functional
approach which incorporates correlations into Poisson-Boltzmann theory by
adding a free energy correction based on the One Component Plasma. We compare
the predictions for ion distribution and osmotic pressure obtained by the full
theory and by its zero temperature limit with Monte Carlo simulations. They
agree excellently for weakly developed correlations and give the correct trend
for stronger ones. In all investigated cases the DHHC theory and its
computationally simpler zero temperature limit yield better results than the
Poisson-Boltzmann theory.Comment: 10 pages, 4 figures, 2 tables, RevTeX4-styl
Strong Attraction between Charged Spheres due to Metastable Ionized States
We report a mechanism which can lead to long range attractions between
like-charged spherical macroions, stemming from the existence of metastable
ionized states. We show that the ground state of a single highly charged
colloid plus a few excess counterions is overcharged. For the case of two
highly charged macroions in their neutralizing divalent counterion solution we
demonstrate that, in the regime of strong Coulomb coupling, the counterion
clouds are very likely to be unevenly distributed, leading to one overcharged
and one undercharged macroion. This long-living metastable configuration in
turn leads to a long range Coulomb attraction.Comment: REVTEX-published versio
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