Non-Markovian dynamics for an open two-level system without rotating wave approximation: Indivisibility versus backflow of information

By use of the two measures presented recently, the indivisibility and the backflow of information, we study the non-Markovianity of the dynamics for a two-level system interacting with a zero-temperature structured environment without using rotating wave approximation (RWA). In the limit of weak coupling between the system and the reservoir, and by expanding the time-convolutionless (TCL) generator to the forth order with respect to the coupling strength, the time-local non-Markovian master equation for the reduced state of the system is derived. Under the secular approximation, the exact analytic solution is obtained and the sufficient and necessary conditions for the indivisibility and the backflow of information for the system dynamics are presented. In the more general case, we investigate numerically the properties of the two measures for the case of Lorentzian reservoir. Our results show the importance of the counter-rotating terms to the short-time-scale non-Markovian behavior of the system dynamics, further expose the relations between the two measures and their rationality as non-Markovian measures. Finally, the complete positivity of the dynamics of the considered system is discussed

Mass measurements of neutron-deficient Y, Zr, and Nb isotopes and their impact on rp and νp nucleosynthesis processes

© 2018 The Authors. Published by Elsevier B.V. This manuscript is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International licence (CC BY-NC-ND 4.0). For further details please see: https://creativecommons.org/licenses/by-nc-nd/4.0/Using isochronous mass spectrometry at the experimental storage ring CSRe in Lanzhou, the masses of 82Zr and 84Nb were measured for the first time with an uncertainty of ∼10 keV, and the masses of 79Y, 81Zr, and 83Nb were re-determined with a higher precision. The latter are significantly less bound than their literature values. Our new and accurate masses remove the irregularities of the mass surface in this region of the nuclear chart. Our results do not support the predicted island of pronounced low α separation energies for neutron-deficient Mo and Tc isotopes, making the formation of Zr–Nb cycle in the rp-process unlikely. The new proton separation energy of 83Nb was determined to be 490(400) keV smaller than that in the Atomic Mass Evaluation 2012. This partly removes the overproduction of the p-nucleus 84Sr relative to the neutron-deficient molybdenum isotopes in the previous νp-process simulations.Peer reviewe

Stemness and chemoresistance in epithelial ovarian carcinoma cells under shear stress

One of greatest challenges to the successful treatment of cancer is drug resistance. An exciting approach is the eradication of cancer stem cells (CSCs). However, little is known about key signals regulating the formation and expansion of CSCs. Moreover, lack of a reliable predictive preclinical model has been a major obstacle to discover new cancer drugs and predict their clinical activity. Here, in ovarian cancer, a highly chemoresistant tumor that is rapidly fatal, we provide the first evidence demonstrating the causal involvement of mechanical stimulus in the CSC phenotype using a customizable microfluidic platform and three-dimensional spheroids, which most closely mimic tumor behavior. We found that ovarian cancer cells significantly acquired the expression of epithelial-to-mesenchymal transition and CSC markers and a remarkable chemoresistance to clinically relevant doses of frontline chemotherapeutic drugs cisplatin and paclitaxel when grown under fluid shear stress, which corroborates with the physiological attainable levels in the malignant ascites, but not under static condition. Furthermore, we uncovered a new link of microRNA-199a-3p, phosphatidylinositol 3-kinase/Akt, and multidrug transporter activation in shear stress-induced CSC enrichment. Our findings shed new light on the significance of hydrodynamics in cancer progression, emphasizing the need of a flow-informed framework in the development of therapeutics

Analysis of Strong-Coupling Parameters for Superfluid 3He

Superfluid $^{3}$He experiments show strong deviation from the weak-coupling limit of the Ginzburg-Landau theory, and this discrepancy grows with increasing pressure. Strong-coupling contributions to the quasiparticle interactions are known to account for this effect and they are manifest in the five $\beta$-coefficients of the fourth order Ginzburg-Landau free energy terms. The Ginzburg-Landau free energy also has a coefficient $g_{z}$ to include magnetic field coupling to the order parameter. From NMR susceptibility experiments, we find the deviation of $g_{z}$ from its weak-coupling value to be negligible at all pressures. New results for the pressure dependence of four different combinations of $\beta$-coefficients, $\beta$_{345}, $\beta$_{12}, $\beta$_{245}, and $\beta$_{5} are calculated and comparison is made with theory.Comment: 6 pages, 2 figures, 1 table. Manuscript prepared for QFS200

Impact of pandemics on primary care:changes in general practitioner antidepressant prescriptions and mental health referrals during lockdowns in England, UK

ObjectivesIn recent times, the world has witnessed unprecedented challenges, with the COVID-19 pandemic being a major disruptor to various aspects of daily life. This article delves into the profound impact of pandemics on primary care, specifically focussing on changes in antidepressant prescriptions and mental health referrals before, during, and after lockdowns in England, UK. MethodsIn this retrospective study, we used anonymised individual-level electronic health record data from general practitioner (GP) practices in the North of England, UK. We applied a negative binomial-logit hurdle model and a multinominal logit regression model to assess the impact on antidepressant prescriptions and GP referral types, respectively. ResultsThe initiation of antidepressant prescriptions showed a notable decrease during and post lockdowns, with a minor uptick in ongoing antidepressant prescriptions during the lockdown periods. Over the course of lockdowns and beyond, there was a growing trend of patients being referred to social prescribing interventions. Notably, individuals from ethnic minorities were more inclined to receive fewer medical treatments and more social prescribing interventions. ConclusionThe increase in antidepressant prescriptions during the pandemic-related lockdowns was expected due to these challenging circumstances. Reduced referrals to secondary mental health services occurred as online counselling services were deemed inappropriate by some doctors, and patients were hesitant to seek face-to-face help. Notably, there was a rise in social prescribing referrals, emerging as a valuable resource for psychological support amid heightened mental health strain. Additionally, ethnic minority patients were less likely to receive medical treatments but more likely to be referred to social prescribing services. Despite the inevitable negative impacts of the COVID-19 pandemic, these findings highlight the active role of non-clinical support in a social model of health, addressing unmet needs and reducing barriers to mental health care for certain groups.</p

Protons in near earth orbit

The proton spectrum in the kinetic energy range 0.1 to 200 GeV was measured by the Alpha Magnetic Spectrometer (AMS) during space shuttle flight STS-91 at an altitude of 380 km. Above the geomagnetic cutoff the observed spectrum is parameterized by a power law. Below the geomagnetic cutoff a substantial second spectrum was observed concentrated at equatorial latitudes with a flux ~ 70 m^-2 sec^-1 sr^-1. Most of these second spectrum protons follow a complicated trajectory and originate from a restricted geographic region.Comment: 19 pages, Latex, 7 .eps figure

Search for antihelium in cosmic rays

The Alpha Magnetic Spectrometer (AMS) was flown on the space shuttle Discovery during flight STS-91 in a 51.7 degree orbit at altitudes between 320 and 390 km. A total of 2.86 * 10^6 helium nuclei were observed in the rigidity range 1 to 140 GV. No antihelium nuclei were detected at any rigidity. An upper limit on the flux ratio of antihelium to helium of < 1.1 * 10^-6 is obtained.Comment: 18 pages, Latex, 9 .eps figure

Enhanced Strength and Ductility of AZ80 Magnesium Alloys by Spray Forming and ECAP Techniques

Fast spray forming technology followed by equal channel angular pressing (ECAP) was employed to obtain a specific microstructure: separated coarse magnesium grains surrounded by deformation networks. The deformation layer consisted of ultrafine grained magnesium with an average grain size of 0.6 μm and ellipsoidal shaped β-Mg17Al12 particles with a size of 200-300 nm and a volume fraction of 13%. Mechanical tensile test demonstrates the advantage of the specific structure: a yield strength of 235MPa combined with an elongation to failure of 14%

A Study of Cosmic Ray Secondaries Induced by the Mir Space Station Using AMS-01

The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics experiment that will study cosmic rays in the $\sim 100 \mathrm{MeV}$ to $1 \mathrm{TeV}$ range and will be installed on the International Space Station (ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the space shuttle \emph{Discovery} from June 2 to June 12, 1998, and collected $10^8$ cosmic ray triggers. Part of the \emph{Mir} space station was within the AMS-01 field of view during the four day \emph{Mir} docking phase of this flight. We have reconstructed an image of this part of the \emph{Mir} space station using secondary $\pi^-$ and $\mu^-$ emissions from primary cosmic rays interacting with \emph{Mir}. This is the first time this reconstruction was performed in AMS-01, and it is important for understanding potential backgrounds during the 3 year AMS-02 mission.Comment: To be submitted to NIM B Added material requested by referee. Minor stylistic and grammer change

Arthroscopy versus arthrocentesis and versus conservative treatments for temporomandibular joint disorders: a systematic review with meta-analysis and trial sequential analysis

The aim of this systematic review was to assess the efficacy of arthroscopy compared to arthrocentesis and to conservative treatments for temporomandibular joint disorders. Thirteen controlled studies on various patient outcomes were included after a systematic search in seven electronic databases. Meta-analyses were conducted separately for arthroscopic surgery (AS) and arthroscopic lysis and lavage (ALL), and short-term (&lt;6 months), intermediate-term (6 months to 5 years), and long-term (≥5 years) follow-up periods were considered. No significant differences in pain reduction and complication rates were found between AS or ALL and arthrocentesis. Regarding improvement in maximum mouth opening (MMO), both AS at intermediate-term and ALL at short-term follow-up were equally efficient when compared to arthrocentesis. However, at intermediate-term follow-up, ALL was superior to arthrocentesis for MMO improvement (mean difference 4.9 mm, 95% confidence interval 2.7–7.1 mm). Trial sequential analysis supported the conclusion of the meta-analysis for MMO improvement for ALL versus arthrocentesis studies at intermediate-term follow-up, but not for the other meta-analyses. Insufficient evidence exists to draw conclusions regarding other patient outcomes or about comparisons between arthroscopy and conservative treatments. Due to the low quality of the primary studies, further research is warranted before final conclusions can be drawn regarding the management of temporomandibular joint disorders