Momentum dynamics of one dimensional quantum walks

We derive the momentum space dynamic equations and state functions for one dimensional quantum walks by using linear systems and Lie group theory. The momentum space provides an analytic capability similar to that contributed by the z transform in discrete systems theory. The state functions at each time step are expressed as a simple sum of three Chebyshev polynomials. The functions provide an analytic expression for the development of the walks with time.Ian Fuss, Langord B. White, Peter J. Sherman, Sanjeev Naguleswara

Genomic epidemiology of SARS-CoV-2 in a UK university identifies dynamics of transmission

AbstractUnderstanding SARS-CoV-2 transmission in higher education settings is important to limit spread between students, and into at-risk populations. In this study, we sequenced 482 SARS-CoV-2 isolates from the University of Cambridge from 5 October to 6 December 2020. We perform a detailed phylogenetic comparison with 972 isolates from the surrounding community, complemented with epidemiological and contact tracing data, to determine transmission dynamics. We observe limited viral introductions into the university; the majority of student cases were linked to a single genetic cluster, likely following social gatherings at a venue outside the university. We identify considerable onward transmission associated with student accommodation and courses; this was effectively contained using local infection control measures and following a national lockdown. Transmission clusters were largely segregated within the university or the community. Our study highlights key determinants of SARS-CoV-2 transmission and effective interventions in a higher education setting that will inform public health policy during pandemics.</jats:p

Parecoxib, propacetamol, and their combination for analgesia after total hip arthroplasty: a randomized non-inferiority trial

BACKGROUND This study assessed non-inferiority of parecoxib vs. combination parecoxib+propacetamol and compared the opioid-sparing effects of parecoxib, propacetamol, and parecoxib+propacetamol vs. placebo after total hip arthroplasty. METHODS In this randomized, placebo-controlled, parallel-group, non-inferiority study, patients received one of four IV treatments after surgery: parecoxib 40 mg bid (n = 72); propacetamol 2 g qid (n = 71); parecoxib 40 mg bid plus propacetamol 2 g qid (n = 72); or placebo (n = 38) with supplemental IV patient-controlled analgesia (morphine). Patients and investigators were blinded to treatment. Pain intensity at rest and with movement was assessed regularly, together with functional recovery (modified Brief Pain Inventory-Short Form) and opioid-related side effects (Opioid-Related Symptom Distress Scale) questionnaires up to 48 h. RESULTS After 24 h, cumulative morphine consumption was reduced by 59.8% (P < 0.001), 38.9% (P < 0.001), and 26.8% (P = 0.005) in the parecoxib+propacetamol, parecoxib, and propacetamol groups, respectively, compared with placebo. Parecoxib did not meet criteria for non-inferiority to parecoxib+propacetamol. Parecoxib+propacetamol and parecoxib significantly reduced least-squares mean pain intensity scores at rest and with movement compared with propacetamol (P < 0.05). One day after surgery, parecoxib+propacetamol significantly reduced opioid-related symptom distress and decreased pain interference with function compared with propacetamol or placebo. CONCLUSION Parecoxib and parecoxib+propacetamol provided significant opioid-sparing efficacy compared with placebo; non-inferiority of parecoxib to parecoxib+propacetamol was not demonstrated. Opioid-sparing efficacy was accompanied by significant reductions in pain intensity on movement, improved functional outcome, and less opioid-related symptom distress. Study medications were well tolerated. Aim: The aim of our study was to compare clinical outcomes and examined the effect of simple decompression without additional fusion in patients with preoperative degenerative spondylolisthesis (DS) versus patients without preoperative degenerative spondylolisthesis (non-DS) on one or two adjacent levels. Methods: For this retrospective analysis we did use data from the Lumbar Stenosis Outcome Study (LSOS). The LSOS is conducted as a prospective cohort study at eight medical centers in Switzerland. The main outcomes of this study were change in SSM symptoms, SSM function, and EQ-5D-EL sum score over time. These outcomes were measured at baseline, six, and 12-month follow-up. To obtain an unbiased effect of DS versus non-DS we chose matching techniques relying on propensity scores. Results: For this study, 853 potentially eligible patients agreed to participate between December 2010 and December 2015. Of these, 350 patients underwent decompression alone surgery within the first six months after baseline. Out of these, 133 patients met the inclusion criteria, with accompanying DS (n = 32) or without DS (n = 101). The estimated effects of DS versus non-DS for change in SSM symptoms from baseline to 6 and 12 months were 0.08 (95% CI −0.34 to 0.49) and 0.16 (−0.23 to 0.55), respectively. For change in SSM function, the estimated effects were −0.01 (−0.39 to 0.37), and 0.08 (−0.33 to 0.50). Changes in between group difference of EQ-5D-EL sum score were estimated to be −7.19 (−15.24 to 0.86) and −4.88 (−13.29 to 3.54) from baseline to 6 and 12 months. None of the group differences between the non-DS and the DS group were statistically significant. All matched patients improved over time in all secondary outcomes. Conclusion: Among the patients with degenerative lumbar spinal stenosis our study demonstrates that in the two groups, degenerative spondylolisthesis and non-degenerative spondylolisthesis, patients distinctively take advantage of simple decompression without fusion. Our results indicate that the presents of a preoperative degenerative spondylolisthesis does not worsen outcome in comparison to non-olisthesis cases when treated by simple decompression. Conversely, our results could indicate that adding fusion in preoperative olisthesis cases might only be reserved for certain patients