Guest Editors' Introduction: Special Issue on Analyzing Interactions in PBL—Where to Go From Here?

published_or_final_versio

Estimation of Buttiker-Landauer traversal time based on the visibility of transmission current

We present a proposal for the estimation of B\"uttiker-Landauer traversal time based on the visibility of transmission current. We analyze the tunneling phenomena with a time-dependent potential and obtain the time-dependent transmission current. We found that the visibility is directly connected to the traversal time. Furthermore, this result is valid not only for rectangular potential barrier but also for general form of potential to which the WKB approximation is applicable . We compared these results with the numerical values obtained from the simulation of Nelson's quantum mechanics. Both of them fit together and it shows our method is very effective to measure experimentally the traversal time.Comment: 12 pages, REVTeX, including 7 eps figure

Tunneling Time Distribution by means of Nelson's Quantum Mechanics and Wave-Particle Duality

We calculate a tunneling time distribution by means of Nelson's quantum mechanics and investigate its statistical properties. The relationship between the average and deviation of tunneling time suggests the exsistence of ``wave-particle duality'' in the tunneling phenomena.Comment: 14 pages including 11 figures, the text has been revise

Time of arrival through interacting environments: Tunneling processes

We discuss the propagation of wave packets through interacting environments. Such environments generally modify the dispersion relation or shape of the wave function. To study such effects in detail, we define the distribution function P_{X}(T), which describes the arrival time T of a packet at a detector located at point X. We calculate P_{X}(T) for wave packets traveling through a tunneling barrier and find that our results actually explain recent experiments. We compare our results with Nelson's stochastic interpretation of quantum mechanics and resolve a paradox previously apparent in Nelson's viewpoint about the tunneling time.Comment: Latex 19 pages, 11 eps figures, title modified, comments and references added, final versio

Bifurcation Phenomenon in a Spin Relaxation

Spin relaxation in a strong-coupling regime (with respect to the spin system) is investigated in detail based on the spin-boson model in a stochastic limit. We find a bifurcation phenomenon in temperature dependence of relaxation constants, which is never observed in the weak-coupling regime. We also discuss inequalities among the relaxation constants in our model and show the well-known relation 2\Gamma_T >= \Gamma_L, for example, for a wider parameter region than before.Comment: REVTeX4, 5 pages, 5 EPS figure

The Exact Correspondence between Phase Times and Dwell Times in a Symmetrical Quantum Tunneling Configuration

The general and explicit relation between the phase time and the dwell time for quantum tunneling or scattering is investigated. Considering a symmetrical collision of two identical wave packets with an one-dimensional barrier, here we demonstrate that these two distinct transit time definitions give connected results where, however, the phase time (group delay) accurately describes the exact position of the scattered particles. The analytical difficulties that arise when the stationary phase method is employed for obtaining phase (traversal) times are all overcome. Multiple wave packet decomposition allows us to recover the exact position of the reflected and transmitted waves in terms of the phase time, which, in addition to the exact relation between the phase time and the dwell time, leads to right interpretation for both of them.Comment: 11 pages, 2 figure

Small Corrections to the Tunneling Phase Time Formulation

After reexamining the above barrier diffusion problem where we notice that the wave packet collision implies the existence of {\em multiple} reflected and transmitted wave packets, we analyze the way of obtaining phase times for tunneling/reflecting particles in a particular colliding configuration where the idea of multiple peak decomposition is recovered. To partially overcome the analytical incongruities which frequently rise up when the stationary phase method is adopted for computing the (tunneling) phase time expressions, we present a theoretical exercise involving a symmetrical collision between two identical wave packets and a unidimensional squared potential barrier where the scattered wave packets can be recomposed by summing the amplitudes of simultaneously reflected and transmitted wave components so that the conditions for applying the stationary phase principle are totally recovered. Lessons concerning the use of the stationary phase method are drawn.Comment: 14 pages, 3 figure

Benefit-risk profile of tofacitinib in patients with moderate-to-severe chronic plaque psoriasis : pooled analysis across six clinical trials

Altres ajuts: This study was funded by Pfizer Inc. The authors would like to thank Maryam Asgari and Charlie Quesenberry, principal investigators of the KPNC database cohort study, and Kevin Winthrop and Jeffrey Curtis, principal investigators of the Medicare database cohort. This study was supported by Pfizer Inc. Medical writing support under the guidance of the authors was provided by Sandrine M. Dupré, PhD, and Carole Evans, PhD, at and on behalf of Complete Medical Communications, Manchester, U.K., and was funded by Pfizer Inc., New York, NY, U.S.A., in accordance with the Good Publication Practice (GPP3) guidelines.Background: Although existing psoriasis treatments are effective and well tolerated in many patients, there is still a need for new effective targeted treatment options. Tofacitinib is an oral Janus kinase inhibitor that has been investigated in patients with moderate-to-severe chronic plaque psoriasis. Objectives: To consider the benefits and risks of tofacitinib in patients with moderate-to-severe psoriasis. Methods: Data were pooled from one phase II, four phase III and one long-term extension study comprising 5204 patient-years of tofacitinib treatment. Efficacy end points included patients achieving Physician's Global Assessments of 'clear' or 'almost clear', ≥ 75% and ≥ 90% reduction in Psoriasis Area and Severity Index (coprimary end points) and improvements in Dermatology Life Quality Index score, Hospital Anxiety and Depression Scale depression score and Itch Severity Item score, at weeks 16 and 52. Safety data were summarized for 3 years of tofacitinib exposure. Results: Tofacitinib 5 and 10 mg twice daily (BID) showed superiority over placebo for all efficacy end points at week 16, with response maintained for 52 weeks of continued treatment. Tofacitinib improved patients' quality of life and was well tolerated. Rates of safety events of interest (except herpes zoster) were similar to those in the published literature and healthcare databases for other systemic psoriasis therapies. Tofacitinib 10 mg BID demonstrated greater efficacy than 5 mg BID. Conclusions: Tofacitinib has a benefit-risk profile in moderate-to-severe psoriasis consistent with that of other systemic treatments

From the cell membrane to the nucleus: unearthing transport mechanisms for Dynein

Mutations in the motor protein cytoplasmic dynein have been found to cause Charcot-Marie-Tooth disease, spinal muscular atrophy, and severe intellectual disabilities in humans. In mouse models, neurodegeneration is observed. We sought to develop a novel model which could incorporate the effects of mutations on distance travelled and velocity. A mechanical model for the dynein mediated transport of endosomes is derived from first principles and solved numerically. The effects of variations in model parameter values are analysed to find those that have a significant impact on velocity and distance travelled. The model successfully describes the processivity of dynein and matches qualitatively the velocity profiles observed in experiments