Subvacuum effects of the quantum field on the dynamics of a test particle

We study the effects of the electromagnetic subvacuum fluctuations on the dynamics of a nonrelativistic charged particle in a wavepacket. The influence from the quantum field is expected to give an additional effect to the velocity uncertainty of the particle. In the case of a static wavepacket, the observed velocity dispersion is smaller in the electromagnetic squeezed vacuum background than in the normal vacuum background. This leads to the subvacuum effect. The extent of reduction in velocity dispersion associated with this subvacuum effect is further studied by introducing a switching function. It is shown that the slow switching process may make this subvacuum effect insignificant. We also point out that when the center of the wavepacket undergoes non-inertial motion, reduction in the velocity dispersion becomes less effective with its evolution, no matter how we manipulate the nonstationary quantum noise via the choice of the squeeze parameters. The role of the underlying fluctuation-dissipation relation is discussed.Comment: 30 pages, 2 figure

P2X₃ Knock-Out Mice Reveal a Major Sensory Role for Urothelially Released ATP

The present study explores the possible involvement of a purinergic mechanism in mechanosensory transduction in the bladder using P2X₃ receptor knock-out (P2X₃ ⁻⁄⁻) and wild-type control (P2X₃ ⁺⁄⁺) mice. Immunohistochemistry revealed abundant nerve fibers in a suburothelial plexus in the mouse bladder that are immunoreactive to anti-P2X₃. P2X₃ -positive staining was completely absent in the subepithelial plexus of the P2X₃ ⁻⁄⁻ mice, whereas staining for calcitonin gene-related peptide and vanilloid receptor 1 receptors remained. Using a novel superfused mouse bladder–pelvic nerve preparation, we detected a release of ATP proportional to the extent of bladder distension in both P2X₃ ⁻⁄⁻ mice, whereas staining for calcitonin gene-related peptide and vanilloid receptor 1 receptors remained. Using a novel superfused mouse bladder–pelvic nerve preparation, we detected a release of ATP proportional to the extent of bladder distension in both P2X₃ ⁺⁄⁺ and P2X₃ ⁻⁄⁻ mice, although P2X₃ ⁻⁄⁻ bladder had an increased capacity compared with that of the P2X₃ ⁺⁄⁺ bladder. The activity of multifiber pelvic nerve afferents increased progressively during gradual bladder distension (at a rate of 0.1 ml/min). However, the bladder afferents from P2X₃ ⁻⁄⁻ mice showed an attenuated response to bladder distension. Mouse bladder afferents of P2X₃ ⁺⁄⁺, but not P2X₃ ⁻⁄⁻, were rapidly activated by intravesical injections of P2X agonists (ATP or α,β-methylene ATP) and subsequently showed an augmented response to bladder distension. By contrast, P2X antagonists [2′,3′-O-(2,4,6-trinitrophenyl)-ATP and pyridoxal 5-phosphate 6-azophenyl-2′,4′-disulfonic acid] and capsaicin attenuated distension-induced discharges in bladder afferents. These data strongly suggest a major sensory role for urothelially released ATP acting via P2X₃ receptors on a subpopulation of pelvic afferent fibers

Daily report cards as a school-based intervention for children with attention-deficit/hyperactivity disorder

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.This paper describes daily report cards and the evidence relating to their use in schools for children with attention-deficit/hyperactivity disorder (ADHD). This intervention typically involves teachers evaluating a student's behaviour at school against pre-determined targets and parents subsequently providing reinforcement at home for positive reports. Research suggests that the daily report card has been effective in treating a range of ADHD symptoms and improving school outcomes, including academic achievement in some cases. The daily report card also encourages collaboration between teachers and parents, and evidence suggests that the intervention benefits from the inclusion of reinforcement at home. Daily report cards are easy to implement and research finds that teachers consider them an acceptable intervention for ADHD. This paper also considers challenges in using daily report cards, including barriers to their use over the long-term and the risk of stigma for children with a report card. Ideas to address these issues are suggested

On the Assumption of Initial Factorization in the Master Equation for Weakly Coupled Systems II: Solvable Models

We analyze some solvable models of a quantum mechanical system in interaction with a reservoir when the initial state is not factorized. We apply Nakajima-Zwanzig's projection method by choosing a reference state of the reservoir endowed with the mixing property. In van Hove's limit, the dynamics is described in terms of a master equation. We observe that Markovianity becomes a valid approximation for timescales that depend both on the form factors of the interaction and on the observables of the reservoir that can be measured.Comment: 25 page

Possible evidence of a spontaneous spin polarization in mesoscopic two-dimensional electron systems

We have experimentally studied the nonequilibrium transport in low-density clean two-dimensional (2D) electron systems at mesoscopic length scales. At zero magnetic field (B), a double-peak structure in the nonlinear conductance was observed close to the Fermi energy in the localized regime. From the behavior of these peaks at nonzero B, we could associate them with the opposite spin states of the system, indicating a spontaneous spin polarization at B=0. Detailed temperature and disorder dependence of the structure shows that such a splitting is a ground-state property of low-density 2D systems

Kondo effect from a tunable bound state within a quantum wire

We investigate the conductance of quantum wires with a variable open quantum dot geometry, displaying an exceptionally strong Kondo effect and most of the 0.7 structure characteristics. Our results indicate that the 0.7 structure is not a manifestation of the singlet Kondo effect. However, specific similarities between our devices and many of the clean quantum wires reported in the literature suggest a weakly bound state is often present in real quantum wires

Cost of Salmonella infections in Australia, 2015

Copyright Ó, International Association for Food Protection Gastroenteritis caused from infections with Salmonella enterica (salmonellosis) causes significant morbidity in Australia. In addition to acute gastroenteritis, approximately 8.8% of people develop irritable bowel syndrome (IBS) and 8.5% of people develop reactive arthritis (ReA). We estimated the economic cost of salmonellosis and associated sequel illnesses in Australia in a typical year circa 2015. We estimated incidence, hospitalizations, other health care usage, absenteeism, and premature mortality for four age groups using a variety of complementary data sets. We calculated direct costs (health care) and indirect costs (lost productivity and premature mortality) by using Monte Carlo simulation to estimate 90% credible intervals (CrI) around our point estimates. We estimated that 90,833 cases, 4,312 hospitalizations, and 19 deaths occurred from salmonellosis in Australia circa 2015 at a direct cost of AUD 23.8 million (90% CrI, 19.3 to 28.9 million) and a total cost of AUD 124.4 million (90% CrI, 107.4 to 143.1 million). When IBS and ReA were included, the estimated direct cost was 35.7 million (90% CrI, 29.9 to 42.7 million) and the total cost was AUD 146.8 million (90% CrI, 127.8 to 167.9 million). Foodborne infections were responsible for AUD 88.9 million (90% CrI, 63.9 to 112.4 million) from acute salmonellosis and AUD 104.8 million (90% CrI, 75.5 to 132.3 million) when IBS and ReA were included. Targeted interventions to prevent illness could considerably reduce costs and societal impact from Salmonella infections and sequel illnesses in Australia

Zero-bias anomaly and kondo-assisted quasiballistic 2D transport

Nonequilibrium transport measurements in mesoscopic quasiballistic 2D electron systems show an enhancement in the differential conductance around the Fermi energy. At very low temperatures, such a zero-bias anomaly splits, leading to a suppression of linear transport at low energies. We also observed a scaling of the nonequilibrium characteristics at low energies which resembles electron scattering by two-state systems, addressed in the framework of two-channel Kondo model. Detailed sample-to-sample reproducibility indicates an intrinsic phenomenon in unconfined 2D systems in the low electron-density regime

Fluctuations of Quantum Radiation Pressure in Dissipative Fluid

Using the generalized Langevin equations involving the stress tensor approach, we study the dynamics of a perfectly reflecting mirror which is exposed to the electromagnetic radiation pressure by a laser beam in a fluid at finite temperature. Based on the fluctuation-dissipation theorem, the minimum uncertainty of the mirror's position measurement from both quantum and thermal noises effects including the photon counting error in the laser interferometer is obtained in the small time limit as compared with the "standard quantum limit". The result of the large time behavior of fluctuations of the mirror's velocity in a dissipative environment can be applied to the laser interferometer of the ground-based gravitational wave detector.Comment: 8 pages. Version published in Physics Letters