Aharonov-Bohm oscillations and magnetic focusing in ballistic graphene rings

We present low-temperature magnetotransport measurements on graphene rings encapsulated in hexagonal boron nitride. We investigate phase-coherent transport and show Aharonov-Bohm (AB) oscillations in quasi-ballistic graphene rings with hard confinement. In particular, we report on the observation of $h/e$, $h/2e$ and $h/3e$ conductance oscillations. Moreover we show signatures of magnetic focusing effects at small magnetic fields confirming ballistic transport. We perform tight binding calculations which allow to reproduce all significant features of our experimental findings and enable a deeper understanding of the underlying physics. Finally, we report on the observation of the AB conductance oscillations in the quantum Hall regime at reasonable high magnetic fields, where we find regions with enhanced AB oscillation visibility with values up to $0.7$%. These oscillations are well explained by taking disorder into account allowing for a coexistence of hard and soft-wall confinement.Comment: 28 pages, 8 figure

Coral Host Cells Acidify Symbiotic Algal Microenvironment to Promote Photosynthesis

Symbiotic dinoflagellate algae residing inside coral tissues supply the host with the majority of their energy requirements through the translocation of photosynthetically fixed carbon. The algae, in turn, rely on the host for the supply of inorganic carbon. Carbon must be concentrated as CO2 in order for photosynthesis to proceed, and here we show that the coral host plays an active role in this process. The host-derived symbiosome membrane surrounding the algae abundantly expresses vacuolar H+-ATPase (VHA), which acidifies the symbiosome space down to pH ∼4. Inhibition of VHA results in a significant decrease in average H+ activity in the symbiosome of up to 75% and a significant reduction in O2 production rate, a measure of photosynthetic activity. These results suggest that host VHA is part of a previously unidentified carbon concentrating mechanism for algal photosynthesis and provide mechanistic evidence that coral host cells can actively modulate the physiology of their symbionts

Does the prescriptive lifestyle of Seventh-Day Adventists provide \u27immunity\u27 from the secular effects of changes in BMI?

Objective: To examine the effect of Seventh-day Adventist (SDA) membership on &lsquo;immunity&rsquo; to the secular effects of changes in BMI.Design: Three independent, cross-sectional, screening surveys conducted by Sydney Adventist Hospital in 1976, 1986 and 1988 and a survey conducted among residents of Melbourne in 2006.Subjects: Two hundred and fifty-two SDA and 464 non-SDA in 1976; 166 SDA and 291 non-SDA in 1986; 120 SDA and 300-non SDA in 1988; and 251 SDA and 294 non-SDA in 2006.Measurements: Height and weight measured by hospital staff in 1976, 1986 and 1988; self-reported by respondents in 2006.Results: The mean BMI of non-SDA men increased between 1986 and 2006 (P &lt; 0&middot;001) but did not change for SDA men or non-SDA women. Despite small increases in SDA women&rsquo;s mean BMI (P = 0&middot;030) between 1988 and 2006, this was no different to that of SDA men and non-SDA women in 2006. The diet and eating patterns of SDA men and women were more &lsquo;prudent&rsquo; than those of non-SDA men and women, including more fruit, vegetables, grains, nuts and legumes, and less alcohol, meat, sweetened drinks and coffee. Many of these factors were found to be predictors of lower BMI.Conclusion: The &lsquo;prudent&rsquo; dietary and lifestyle prescriptions of SDA men appear to have &lsquo;immunised&rsquo; them to the secular effects of changes that occurred among non-SDA men&rsquo;s BMI. The dietary and lifestyle trends of SDA women did not reflect the increase in their BMI observed in 2006.<br /

Frequency and Types of Healthcare Encounters in the Week Preceding a Sepsis Hospitalization: A Systematic Review

OBJECTIVES: Early recognition and treatment are critical to improving sepsis outcomes. We sought to identify the frequency and types of encounters that patients have with the healthcare system in the week prior to a sepsis hospitalization. DATA SOURCES: PubMed, Cumulative Index to Nursing and Allied Health Literature, Scopus, and the Cochrane Library. STUDY SELECTION: Observational cohort studies of patients hospitalized with sepsis or septic shock that were assessed for an outpatient or emergency department encounter with the healthcare system in the week prior to hospital admission. DATA EXTRACTION: The primary outcome was the proportion of patients with a healthcare encounter in the time period assessed (up to 1 week) prior to a hospitalization with sepsis. DATA SYNTHESIS: Six retrospective observational studies encompassing 6,785,728 sepsis admissions were included for evaluation, ranging from a 263-patient single-center cohort to a large database evaluating 6,731,827 sepsis admissions. The average (unweighted) proportion of patients having an encounter with the healthcare system in the week prior to a sepsis hospitalization was 32.7% and ranged from 10.3% to 52.9%. These encounters commonly involved presentation or potential symptoms of infectious diseases, antibiotic prescriptions, and appeared to increase in frequency closer to a sepsis hospitalization admission. No consistent factors were identified that distinguished a healthcare encounter as more or less likely to precede a sepsis hospitalization in the subsequent week. CONCLUSIONS: Patients that present to the hospital with sepsis are frequently evaluated in the healthcare system in the week prior to admission. Further research is necessary to understand if these encounters offer earlier opportunities for intervention to prevent the transition from infection to sepsis, whether they merely reflect the comorbidities of sepsis patients with a high baseline rate of healthcare encounters, or the declining trajectory of a patient\u27s overall health in response to infection

Parameters of Herbig Ae/Be and Vega-type stars

This work presents the determination of the effective temperature, gravity, metallicity, mass, luminosity and age of 27 young early-type stars, most of them in the age range 1-10 Myr, and three -suspected- hot companions of post-T Tauri stars belonging to the Lindroos binary sample. Most of these objects show IR excesses in their spectral energy distributions, which are indicative of the presence of disks. The work is relevant in the fields of stellar physics, physics of disks and formation of planetary systems. Spectral energy distributions and mid-resolution spectra were used to estimate the effective temperature. The comparison of the profiles of the Balmer lines with synthetic profiles provides the value of the stellar gravity. High-resolution optical observations and synthetic spectra are used to estimate the metallicity, [M/H]. Once these three parameters are known for each star, evolutionary tracks and isochrones provide estimations of the mass, luminosity, age and distance (or upper limits in some cases). The method is original in the sense that it is distance-independent, i.e. the estimation of the stellar parameters does not require, as it happens in other works, the knowledge of the distance to the object. A detailed discussion on some individual objects, in particular VV Ser, RR Tau, 49 Cet and the three suspected hot companions of post-T Tauris, is presented. The paper also shows the difficulty posed by the morphology and behaviour of the system star+disk in the computation of the stellar parameters.Comment: 18 pages, 11 figure

The Wage and Non-wage Costs of Displacement: Evidence from Russia

This paper is the first to analyze the costs of job loss in Russia, using unique new data from the Russian Longitudinal Monitoring Survey over the years 2003-2008, including a special supplement on displacement that was initiated by us. We employ fixed effects regression models and propensity score matching techniques in order to establish the causal effect of displacement for displaced individuals. The paper is innovative insofar as we investigate fringe and in-kind benefits and the propensity to have an informal employment relationship as well as a permanent contract as relevant labor market outcomes upon displacement. We also analyze monthly earnings, hourly wages, employment and hours worked, which are traditionally investigated in the literature. Compared to the control group of non-displaced workers (i.e. stayers and quitters), displaced individuals face a significant income loss following displacement, which is mainly due to the reduction in employment and hours worked. This effect is robust to the definition of displacement. The losses seem to be more pronounced and are especially large for older workers with labor market experience and human capital acquired in Soviet times and for workers with primary and secondary education. Workers displaced from state firms experience particularly large relative losses in the short run, while such losses for workers laid off from private firms are more persistent. Turning to the additional non-conventional labor market outcomes, there is a loss in terms of the number of fringe and in-kind benefits for reemployed individuals but not in terms of their value. There is also some evidence of an increased probability of working in informal jobs if displaced. These results point towards the importance of both firm-specific human capital and of obsolete skills obtained under the centrally planned economy as well as to a wider occurrence of job insecurity among displaced workers

The planetary system host HR\,8799: On its λ\lambda Bootis nature

HR\,8799 is a $\lambda$ Bootis, $\gamma$ Doradus star hosting a planetary system and a debris disk with two rings. This makes this system a very interesting target for asteroseismic studies. This work is devoted to the determination of the internal metallicity of this star, linked with its $\lambda$ Bootis nature (i.e., solar surface abundances of light elements, and subsolar surface abundances of heavy elements), taking advantage of its $\gamma$ Doradus pulsations. This is the most accurate way to obtain this information, and this is the first time such a study is performed for a planetary-system-host star. We have used the equilibrium code CESAM and the non-adiabatic pulsational code GraCo. We have applied the Frequency Ratio Method (FRM) and the Time Dependent Convection theory (TDC) to estimate the mode identification, the Brunt-Va\"is\"al\"a frequency integral and the mode instability, making the selection of the possible models. When the non-seismological constraints (i.e its position in the HR diagram) are used, the solar abundance models are discarded. This result contradicts one of the main hypothesis for explaining the $\lambda$ Bootis nature, namely the accretion/diffusion of gas by a star with solar abundance. Therefore, according to these results, a revision of this hypothesis is needed. The inclusion of accurate internal chemical mixing processes seems to be necessary to explain the peculiar abundances observed in the surface of stars with internal subsolar metallicities. The use of the asteroseismological constraints, like those provided by the FRM or the instability analysis, provides a very accurate determination of the physical characteristics of HR 8799. However, a dependence of the results on the inclination angle $i$ still remains. The determination of this angle, more accurate multicolour photometric observations, and high resolution spectroscopy can definitively fix the mass and metallicity of this star.Comment: 11 pages, 10 figures. Accepted for publication in MNRA

Surviving severe COVID-19: Interviews with patients, informal carers and health professionals

Background:The COVID-19 pandemic has been associated with an unprecedentednumber of critical care survivors. Their experiences through illness and recovery arelikely to be complex, but little is known about how best to support them. This studyaimed to explore experiences of illness and recovery from the perspective of survi-vors, their relatives and professionals involved in their care.Study design:In-depth qualitative interviews were conducted with three stakeholdergroups during the first wave of the pandemic. A total of 23 participants (12 profes-sionals, 6 survivors and 5 relatives) were recruited from 5 acute hospitals in Englandand interviewed by telephone or video call. Data analysis followed the principles ofReflexive Thematic Analysis.Findings:Three themes were generated from their interview data: (1) Deterioratingfast—a downhill journey from symptom onset to critical care; (2) Facing a new virusin a hospital—a remote place; and (3) Returning home as a survivor, maintaining nor-mality and recovering slowly.Conclusions:Our findings highlight challenges in accessing care and communicationbetween patients, hospital staff and relatives. Following hospital discharge, patientsadopted a reframed‘survivor identity’to cope with their experience of illness andslow recovery process. The concept of survivorship in this patient group may be ben-eficial to promote and explore further.Relevance to clinical practice:All efforts should be made to continue to improvecommunication between patients, relatives and health professionals during criticalcare admissions, particularly while hospital visits are restricted. Adapting to life aftercritical illness may be more challenging while health services are restricted by theimpacts of the pandemic. It may be beneficial to promote the concept of survivorship,following admission to critical care due to severe COVID-19