Suppression of 2\pi\ phase-slip due to hidden zero modes in one dimensional topological superconductors

We study phase slips in one-dimensional topological superconducting wires. These wires have been proposed as building blocks for topologically protected qubits in which the quantum information is distributed over the length of the device and thus is immune to local sources of decoherence. However, phase-slips are non-local events that can result in decoherence. Phase slips in topological superconductors are peculiar for the reason that they occur in multiples of 4\pi\ (instead of 2\pi\ in conventional superconductors). We re-establish this fact via a beautiful analogy to the particle physics concept of dynamic symmetry breaking by explicitly finding a "hidden" zero mode in the fermion spectrum computed in the background of a 2\pi\ phase-slip. Armed with the understanding of phase-slips in topological superconductors, we propose a simple experimental setup with which the predictions can be tested by monitoring tunneling rate of a superconducting flux quantum through a topological superconducting wire.Comment: 18 pages,14 figures, Updated referenc

24th Annual Richard A. Harrison Symposium: A Celebration of Student Research and Achievement in the Humanities and Social Sciences

The Harrison Symposium celebrates independent and collaborative student research in the Social Sciences and Humanities. The Harrison is usually held as an annual conference in May, but this year’s shift to remote teaching and the new coronavirus pandemic eliminated the opportunity for in-person presentations. Instead of cancelling the event, students nominated by faculty members were invited either to participate in next year’s Harrison, or to contribute to the volume you are now reading. Reimagining the Harrison as a written artifact was inspired by the 1997 Harrison Symposium. In the early years of the conference, the Dean of Faculty Richard A. Harrison (1991-1997) published the proceedings of the symposium – formerly known as the Humanities and Social Sciences Symposium though the event was later renamed in Harrison’s honor – as a collection of papers. Margaret E. Madden, then Associate Dean of the Faculty, notes in the introduction to the 1998 proceedings that “Faculty members and departments on campus who received the first symposium collection were pleased to have some visible record of the high level of accomplishments of humanities and social science students, whose products are often not as visible as those students of the performing arts or sciences.” I hope that this version of the Harrison will also serve as a way to publicly and communally celebrate the wide-ranging and incisive research undertaken by students at Lawrence

Singlet versus Triplet Reactivity in an Mn(V)-Oxo Species:Testing Theoretical Predictions Against Experimental Evidence

Discerning the factors that control the reactivity of high-valent metal–oxo species is critical to both an understanding of metalloenzyme reactivity and related transition metal catalysts. Computational studies have suggested that an excited higher spin state in a number of metal–oxo species can provide a lower energy barrier for oxidation reactions, leading to the conclusion that this unobserved higher spin state complex should be considered as the active oxidant. However, testing these computational predictions by experiment is difficult and has rarely been accomplished. Herein, we describe a detailed computational study on the role of spin state in the reactivity of a high-valent manganese­(V)–oxo complex with para-Z-substituted thioanisoles and utilize experimental evidence to distinguish between the theoretical results. The calculations show an unusual change in mechanism occurs for the dominant singlet spin state that correlates with the electron-donating property of the para-Z substituent, while this change is not observed on the triplet spin state. Minimum energy crossing point calculations predict small spin–orbit coupling constants making the spin state change from low spin to high spin unlikely. The trends in reactivity for the para-Z-substituted thioanisole derivatives provide an experimental measure for the spin state reactivity in manganese–oxo corrolazine complexes. Hence, the calculations show that the V-shaped Hammett plot is reproduced by the singlet surface but not by the triplet state trend. The substituent effect is explained with valence bond models, which confirm a change from an electrophilic to a nucleophilic mechanism through a change of substituent

COMPARING NO-FAULT COMPENSATION SYSTEMS FOR VACCINE INJURY

The policy responses to redressing serious adverse reactions caused by vaccines are many and varied. Scholars have identified three broad options for responding to the need for support of those who have been subject to vaccine injury. The first is a minimalist approach that entails injured persons bearing the costs associated with their injuries with assistance provided solely by means of standard social welfare and health benefits provided by the state. Second, compensation may be sought through legal proceedings brought against those responsible for producing, or in certain cases distributing, the vaccines in question. Third, compensation may be sought from a dedicated compensation scheme outside the normal litigation system, generally premised upon no-fault liability. The discussion in this Article focuses on the latter schemes, which are generally government-created and specifically respond to vaccine injuries. The advantages of such a mechanism over the other options, which entail either patients bearing the costs themselves or seeking compensation though litigation against private sector, have been widely discussed, and we will also examine the broader rationales below

At-wavelength optical metrology development at the ALS

Nano-focusing and brightness preservation for ever brighter synchrotron radiation and free electron laser beamlines require surface slope tolerances of x-ray optics on the order of 100 nrad. While the accuracy of fabrication and ex situ metrology of x-ray mirrors has improved over time, beamline in situ performance of the optics is often limited by application specific factors such as x-ray beam heat loading, temperature drift, alignment, vibration, etc. In the present work, we discuss the recent results from the Advanced Light Source developing high accuracy, in situ, at-wavelength wavefront measurement techniques to surpass 100-nrad accuracy surface slope measurements with reflecting x-ray optics. The techniques will ultimately allow closed-loop feedback systems to be implemented for x-ray nano-focusing. In addition, we present a dedicated metrology beamline endstation, applicable to a wide range of in situ metrology and test experiments. The design and performance of a bendable Kirkpatrick-Baez (KB) mirror with active temperature stabilization will also be presented. The mirror is currently used to study, refine, and optimize in situ mirror alignment, bending and metrology methods essential for nano-focusing application

Creatinine clearance versus serum creatinine as a risk factor in cardiac surgery

BACKGROUND: Renal impairment is one of the predictors of mortality in cardiac surgery. Usually a binarized value of serum creatinine is used to assess the renal function in risk models. Creatinine clearance can be easily estimated by the Cockcroft and Gault equation from serum creatinine, gender, age and body weight. In this work we examine whether this estimation of the glomerular filtration rate can advantageously replace the serum creatinine in the EuroSCORE preoperative risk assessment. METHODS: In a group of 8138 patients out of a total of 11878 patients, who underwent cardiac surgery in our hospital between January 1996 and July 2002, the 18 standard EuroSCORE parameters could retrospectively be determined and logistic regression analysis performed. In all patients scored, creatinine clearance was calculated according to Cockcroft and Gault. The relationship between the predicted and observed 30-days mortality was evaluated in systematically selected intervals of creatinine clearance and significance values computed by employing Monte Carlo methods. Afterwards, risk scoring was performed using a continuous or a categorical value of creatinine clearance instead of serum creatinine. The predictive ability of several risk score models and the individual contribution of their predictor variables were studied using ROC curve analysis. RESULTS: The comparison between the expected and observed 30-days mortalities, which were determined in different intervals of creatinine clearance, revealed the best threshold value of 55 ml/min. A significantly higher 30-days mortality was observed below this threshold and vice versa (both with p < 0.001). The local adaptation of the EuroSCORE is better than the standard EuroSCORE and was further improved by replacing serum creatinine (SC) by creatinine clearance (CC). Differential ROC analysis revealed that CC is superior to SC in providing predictive power within the logistic regression. Variable rank comparison identified CC as the best single variable predictor, even better than the variable age, former number 1, and SC, previously number 9 in the standard set of EuroSCORE variables. CONCLUSION: The renal function is an important determinant of mortality in heart surgery. This risk factor is not well captured in the standard EuroSCORE risk evaluation system. Our study shows that creatinine clearance, calculated according to the Cockcroft and Gault equation, should be applied to estimate the preoperative renal function instead of serum creatinine. This predictor variable replacement gains a significant improvement in the predictive accuracy of the scoring model

Relation of severe COVID-19 in Scotland to transmission-related factors and risk conditions eligible for shielding support:REACT-SCOT case-control study

Abstract Background Clinically vulnerable individuals have been advised to shield themselves during the COVID-19 epidemic. The objectives of this study were to investigate (1) the rate ratio of severe COVID-19 associated with eligibility for the shielding programme in Scotland across the first and second waves of the epidemic and (2) the relation of severe COVID-19 to transmission-related factors in those in shielding and the general population. Methods In a matched case-control design, all 178,578 diagnosed cases of COVID-19 in Scotland from 1 March 2020 to 18 February 2021 were matched for age, sex and primary care practice to 1,744,283 controls from the general population. This dataset (REACT-SCOT) was linked to the list of 212,702 individuals identified as eligible for shielding. Severe COVID-19 was defined as cases that entered critical care or were fatal. Rate ratios were estimated by conditional logistic regression. Results With those without risk conditions as reference category, the univariate rate ratio for severe COVID-19 was 3.21 (95% CI 3.01 to 3.41) in those with moderate risk conditions and 6.3 (95% CI 5.8 to 6.8) in those eligible for shielding. The highest rate was in solid organ transplant recipients: rate ratio 13.4 (95% CI 9.6 to 18.8). Risk of severe COVID-19 increased with the number of adults but decreased with the number of school-age children in the household. Severe COVID-19 was strongly associated with recent exposure to hospital (defined as 5 to 14 days before presentation date): rate ratio 12.3 (95% CI 11.5 to 13.2) overall. The population attributable risk fraction for recent exposure to hospital peaked at 50% in May 2020 and again at 65% in December 2020. Conclusions The effectiveness of shielding vulnerable individuals was limited by the inability to control transmission in hospital and from other adults in the household. Mitigating the impact of the epidemic requires control of nosocomial transmission

Mortality in hepatitis C patients who achieve a sustained viral response compared to the general population

Background &#38; Aims: The number of people living with previous hepatitis C infection that have attained a sustained viral response (SVR) is expected to grow rapidly. So far, the prognosis of this group relative to the general population is unclear. Methods: Individuals attaining SVR in Scotland in 1996–2011 were identified using a national database. Through record-linkage, we obtained cause-specific mortality data complete to Dec 2013. We calculated standardised mortality ratios (SMRs) to compare the frequency of mortality in SVR patients to the general population. In a parallel analysis, we used Cox regression to identify modifiable patient characteristics associated with post-SVR mortality. Results: We identified 1824 patients, followed on average for 5.2 years after SVR. In total, 78 deaths were observed. Overall, all-cause mortality was 1.9 times more frequent for SVR patients than the general population (SMR: 1.86; 95% confidence interval (CI): 1.49–2.32). Significant cause-specific elevations were seen for death due to primary liver cancer (SMR: 23.50; 95% CI: 12.23–45.16), and death due to drug-related causes (SMR: 6.58, 95% CI: 4.15–10.45). Together these two causes accounted for 66% of the total excess death observed. All of the modifiable characteristics associated with increased mortality were markers either of heavy alcohol use or injecting drug use. Individuals without these behavioural markers (32.8% of cohort) experienced equivalent survival to the general population (SMR: 0.70; 95% CI: 0.41–1.18) Conclusions: Mortality in Scottish SVR patients is higher overall than the general population. The excess was driven by death from drug-related causes and liver cancer. Health risk behaviours emerged as important modifiable determinants of mortality in this population. Lay summary: Patients cured of hepatitis C through treatment had a higher mortality rate overall than the general population. Most of the surplus mortality was due to drug-related causes and death from liver cancer. A history of heavy alcohol and injecting drug use were associated with a higher mortality risk

Home-based pre-surgical psychological intervention for knee osteoarthritis (HAPPiKNEES): a feasibility randomized controlled trial

Objective: To determine the feasibility of conducting a trial of a pre-surgical psychological intervention on pain, function, and mood in people with knee osteoarthritis listed for total knee arthroplasty. Design: Multi-centre, mixed-methods feasibility randomized controlled trial of intervention plus usual care versus usual care. Setting: Participants’ homes or hospital. Participants: Patients with knee osteoarthritis listed for total knee arthroplasty and score >7 on either subscales of Hospital Anxiety and Depression Scale. Intervention: Up-to 10 sessions of psychological intervention (based on cognitive behavioural therapy). Main measures: Feasibility outcomes (recruitment and retention rates, acceptability of trial procedures and intervention, completion of outcome measures), and standardized questionnaires assessing pain, function, and mood at baseline, and four and six months post-randomisation. Results: Of 222 people screened, 81 did not meet inclusion criteria, 64 did not wish to participate, 26 were excluded for other reasons, and 51 were randomized. A total of 30 completed 4-months outcomes and 25 completed 6-month outcomes. Modal number of intervention sessions completed was three (range 2–8). At six-month follow-up, mood, pain, and physical function scores were consistent with clinically important benefits from intervention, with effect sizes ranging from small (d = 0.005) to moderate (d = 0.74), and significant differences in physical function between intervention and usual care groups (d = 1.16). Feedback interviews suggested that participants understood the rationale for the study, found the information provided adequate, the measures comprehensive, and the intervention acceptable. Conclusion: A definitive trial is feasible, with a total sample size of 444 people. Pain is a suitable primary outcome, but best assessed 6 and 12 months post-surgery