Observing the evolution of a quantum system that does not evolve

This article deals with the problem of gathering information on the time evolution of a single metastable quantum system whose evolution is impeded by the quantum Zeno effect. It has been found it is in principle possible to obtain some information on the time evolution and, depending on the specific system, even to measure its average decay rate, even if the system does not undergo any evolution at all.Comment: Two over three PRA referees didn't like the old title... And no more quantum circuits in the new versio

Accurate Determination of Conformational Transitions in Oligomeric Membrane Proteins

The structural dynamics governing collective motions in oligomeric membrane proteins play key roles in vital biomolecular processes at cellular membranes. In this study, we present a structural refinement approach that combines solid-state NMR experiments and molecular simulations to accurately describe concerted conformational transitions identifying the overall structural, dynamical, and topological states of oligomeric membrane proteins. The accuracy of the structural ensembles generated with this method is shown to reach the statistical error limit, and is further demonstrated by correctly reproducing orthogonal NMR data. We demonstrate the accuracy of this approach by characterising the pentameric state of phospholamban, a key player in the regulation of calcium uptake in the sarcoplasmic reticulum, and by probing its dynamical activation upon phosphorylation. Our results underline the importance of using an ensemble approach to characterise the conformational transitions that are often responsible for the biological function of oligomeric membrane protein states

Leptogenesis in models with keV sterile neutrino dark matter

We analyze leptogenesis in gauge extensions of the Standard Model with keV sterile neutrino dark matter. We find that both the observed dark matter abundance and the correct baryon asymmetry of the Universe can simultaneously emerge in these models. Both the dark matter abundance and the leptogenesis are controlled by the out of equilibrium decays of the same heavy right handed neutrino.Comment: 6 pages, 1 figur

Contract Negotiation Skills: A Workshop for Women in Medicine

© 2020 Simone et al. Introduction: Contract negotiation is a high-stakes interaction, yet most physicians are never taught negotiation skills. Studies suggest that women, as compared with men, display a lower propensity to initiate negotiations and negotiate less competitively, highlighting a need for training to help level the playing field for female physicians. Methods: We devised a learner-centered workshop for female physicians that included a mini-didactic on negotiation principles, a question-and-answer time with a lawyer, an interactive role-play on contract negotiation style, and guided reflection. The workshop was intended for women in medicine from the level of medical student to full professor. The workshop was evaluated by pre- and postworkshop surveys with quantitative questions assessing perceived comfort with and knowledge of negotiation skills and strategies, as well as qualitative questions assessing lessons learned and areas for improvement. Results: After the workshop, participants (n = 34) reported significantly improved comfort with contract negotiation (p \u3c .01) and with negotiation skills and strategies (p \u3c .01). Through qualitative evaluation, we discovered that participants gained an appreciation for the self-advocacy in negotiation, as well as a better understanding of negotiation logistics. We also received positive feedback from participant comments, with most learners reporting that the topic was useful and worthwhile. Discussion: We believe that this workshop fills a gap in the literature regarding contract negotiation training for physicians while also helping to level the playing field with regard to female physicians and the gender pay gap

Strengthening measurements from the edges: application-level packet loss rate estimation

Network users know much less than ISPs, Internet exchanges and content providers about what happens inside the network. Consequently users cannot either easily detect network neutrality violations or readily exercise their market power by knowledgeably switching ISPs. This paper contributes to the ongoing efforts to empower users by proposing two models to estimate -- via application-level measurements -- a key network indicator, i.e., the packet loss rate (PLR) experienced by FTP-like TCP downloads. Controlled, testbed, and large-scale experiments show that the Inverse Mathis model is simpler and more consistent across the whole PLR range, but less accurate than the more advanced Likely Rexmit model for landline connections and moderate PL

B→πℓνlB \to \pi \ell \nu_l Width and ∣Vub∣|V_{ub}| from QCD Light-Cone Sum Rules

We employ the $B\to\pi$ form factors obtained from QCD light-cone sum rules and calculate the $B\to \pi \ell \nu_l$ width ($\ell=e,\mu$) in units of $1/|V_{ub}|^2$, integrated over the region of accessible momentum transfers, $0\leq q^2\leq 12.0 ~GeV^2$. Using the most recent BABAR-collaboration measurements we extract $|V_{ub}|=(3.50^{+0.38}_{-0.33}\big|_{th.}\pm 0.11 \big|_{exp.})\times 10^{-3}$. The sum rule results for the form factors, taken as an input for a $z$-series parameterization, yield the $q^2$-shape in the whole semileptonic region of $B\to \pi\ell\nu_\ell$. We also present the charged lepton energy spectrum in this decay. Furthermore, the current situation with $B\to \tau\nu_\tau$ is discussed from the QCD point of view. We suggest to use the ratio of the $B\to \pi \tau\nu_\tau$ and $B\to \pi\ell \nu_l ~(\ell =\mu,e)$ widths as an additional test of Standard Model. The sensitivity of this observable to new physics is illustrated by including a charged Higgs-boson contribution in the semileptonic decay amplitude.Comment: 22 pages, 8 figures; comments added in section 4, version to be published in Phys. Rev.

Acoustic behavior of melon-headed whales varies on a diel cycle.

Many terrestrial and marine species have a diel activity pattern, and their acoustic signaling follows their current behavioral state. Whistles and echolocation clicks on long-term recordings produced by melon-headed whales (Peponocephala electra) at Palmyra Atoll indicated that these signals were used selectively during different phases of the day, strengthening the idea of nighttime foraging and daytime resting with afternoon socializing for this species. Spectral features of their echolocation clicks changed from day to night, shifting the median center frequency up. Additionally, click received levels increased with increasing ambient noise during both day and night. Ambient noise over a wide frequency band was on average higher at night. The diel adjustment of click features might be a reaction to acoustic masking caused by these nighttime sounds. Similar adaptations have been documented for numerous taxa in response to noise. Or it could be, unrelated, an increase in biosonar source levels and with it a shift in center frequency to enhance detection distances during foraging at night. Call modifications in intensity, directionality, frequency, and duration according to echolocation task are well established for bats. This finding indicates that melon-headed whales have flexibility in their acoustic behavior, and they collectively and repeatedly adapt their signals from day- to nighttime circumstances

Which sexual abuse victims receive a forensic medical examination? : The impact of Children\u27s Advocacy Centers

Abstract Objective This study examines the impact of Children\u27s Advocacy Centers (CAC) and other factors, such as the child\u27s age, alleged penetration, and injury on the use of forensic medical examinations as part of the response to reported child sexual abuse. Methods This analysis is part of a quasi-experimental study, the Multi-Site Evaluation of Children\u27s Advocacy Centers, which evaluated four CACs relative to within-state non-CAC comparison communities. Case abstractors collected data on forensic medical exams in 1,220 child sexual abuse cases through review of case records. Results Suspected sexual abuse victims at CACs were two times more likely to have forensic medical examinations than those seen at comparison communities, controlling for other variables. Girls, children with reported penetration, victims who were physically injured while being abused, White victims, and younger children were more likely to have exams, controlling for other variables. Non-penetration cases at CACs were four times more likely to receive exams as compared to those in comparison communities. About half of exams were conducted the same day as the reported abuse in both CAC and comparison communities. The majority of caregivers were very satisfied with the medical professional. Receipt of a medical exam was not associated with offenders being charged. Conclusions Results of this study suggest that CACs are an effective tool for furthering access to forensic medical examinations for child sexual abuse victims