The Rotating-Wave Approximation: Consistency and Applicability from an Open Quantum System Analysis

We provide an in-depth and thorough treatment of the validity of the rotating-wave approximation (RWA) in an open quantum system. We find that when it is introduced after tracing out the environment, all timescales of the open system are correctly reproduced, but the details of the quantum state may not be. The RWA made before the trace is more problematic: it results in incorrect values for environmentally-induced shifts to system frequencies, and the resulting theory has no Markovian limit. We point out that great care must be taken when coupling two open systems together under the RWA. Though the RWA can yield a master equation of Lindblad form similar to what one might get in the Markovian limit with white noise, the master equation for the two coupled systems is not a simple combination of the master equation for each system, as is possible in the Markovian limit. Such a naive combination yields inaccurate dynamics. To obtain the correct master equation for the composite system a proper consideration of the non-Markovian dynamics is required.Comment: 17 pages, 0 figures

Acquisition of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) carriage after exposure to systemic antimicrobials during travel: systematic review and meta-analysis

BACKGROUND: International travel is an important risk factor for colonization with extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE). Antimicrobial use during travel likely amplifies this risk, yet to what extent, and whether it varies by antimicrobial class, has not been established. METHODS: We conducted a systematic review that included prospective cohorts reporting both receipt of systemic antimicrobials and acquired ESBL-PE isolated from stool or rectum during international travel. We performed a random effects meta-analysis to estimate odds of acquiring ESBL-PE due to antimicrobials during travel, overall and by antimicrobial class. RESULTS: Fifteen studies were included. The study population was mainly female travellers from high income countries recruited primarily from travel clinics. Participants travelled most frequently to Asia and Africa with 10% reporting antimicrobial use during travel. The combined odds ratio (OR) for ESBL-PE acquisition during travel was 2.37 for antimicrobial use overall (95% confidence interval [CI], 1.69 to 3.33), but there was substantial heterogeneity between studies. Fluoroquinolones were the antibiotic class associated with the highest combined OR of ESBL-PE acquisition, compared to no antimicrobial use (OR 4.68, 95% CI, 2.34 to 9.37). CONCLUSIONS: The risk of ESBL-PE colonization during travel is increased substantially with exposure to antimicrobials, especially fluoroquinolones. While a small proportion of colonized individuals will develop a resistant infection, there remains the potential for onward spread among returning travellers. Public health efforts to decrease inappropriate antimicrobial usage during travel are warranted

An evaluation of dental antibiotic prescribing practices in the United States

Background Antibiotic prescribing practices among general dentists and dental specialists in the United States remains poorly understood. The purpose of this study was to compare prescribing practices across dental specialties, evaluate the duration of antibiotics dentists prescribed, and determine variation in antibiotic selection among dentists. Methods The authors performed a retrospective cross-sectional analysis of dental care provider specialties linked to deidentified antibiotic claims data from a large pharmacy benefits manager during the 2015 calendar year. Results As a group, general dentists and dental specialists were responsible for more than 2.9 million antibiotic prescriptions, higher than levels for several other medical and allied health care provider specialties. Antibiotic treatment duration generally was prolonged and commonly included broad-spectrum agents, such as amoxicillin clavulanate and clindamycin. Although amoxicillin was the most commonly prescribed antibiotic among all dental specialties, there was substantial variation among other antibiotics each specialty selected. The most common antibiotic treatment durations were 7 and 10 days. Conclusions This study’s results demonstrate that dentists frequently prescribe antibiotics for prolonged periods and often use broad-spectrum antibiotics. Further studies are necessary to evaluate the appropriateness of these antibiotic prescribing patterns. Practical Implications The clinically significant variation in antibiotic selection and treatment duration identified among all dental specialties in this study population implies that further research and guidance into the treatment of dental infections is necessary to improve and standardize antibiotic prescribing practices

MARVELS-1: A face-on double-lined binary star masquerading as a resonant planetary system; and consideration of rare false positives in radial velocity planet searches

We have analyzed new and previously published radial velocity observations of MARVELS-1, known to have an ostensibly substellar companion in a ~6- day orbit. We find significant (~100 m/s) residuals to the best-fit model for the companion, and these residuals are naively consistent with an interior giant planet with a P = 1.965d in a nearly perfect 3:1 period commensuribility (|Pb/Pc - 3| < 10^{-4}). We have performed several tests for the reality of such a companion, including a dynamical analysis, a search for photometric variability, and a hunt for contaminating stellar spectra. We find many reasons to be critical of a planetary interpretation, including the fact that most of the three-body dynamical solutions are unstable. We find no evidence for transits, and no evidence of stellar photometric variability. We have discovered two apparent companions to MARVELS-1 with adaptive optics imaging at Keck; both are M dwarfs, one is likely bound, and the other is likely a foreground object. We explore false-alarm scenarios inspired by various curiosities in the data. Ultimately, a line profile and bisector analysis lead us to conclude that the ~100 m/s residuals are an artifact of spectral contamination from a stellar companion contributing ~15-30% of the optical light in the system. We conclude that origin of this contamination is the previously detected radial velocity companion to MARVELS-1, which is not, as previously reported, a brown dwarf, but in fact a G dwarf in a face-on orbit.Comment: ApJ 770, 119. 24 pp emulate ApJ style, 12 figures (One is very large). v2: corrects two (important!) errors: A priori chance of this alignment or worse is 0.1% (not 0.01%) and the primary has THREE total companions (not four

Longitudinal antibiotic prescribing trends among US dental specialists within a pharmacy benefits manager, 2013 through 2015

Background Reducing inappropriate antibiotic prescriptions (Rxs) is a major quality improvement initiative in the United States. Tracking antibiotic prescribing trends is 1 method of assessing improvement in antibiotic prescribing. The purpose of this study was to assess longitudinal antibiotic prescribing practices among dental specialists. Methods This was a retrospective ecological longitudinal trend study. The authors calculated monthly systemic antibiotic Rx counts, and rates per 100,000 beneficiaries, from a pharmacy benefits manager in the United States from 2013 through 2015. The authors calculated average annual antibiotic Rx rates (AARs) for the 3-year study period. The authors used a quasi-Poisson regression model to analyze antibiotic Rx trends. The authors quantified seasonal trends, when present, via peak-to-trough ratios (PTTRs). Results Dental specialists prescribed 2.4 million antibiotics to the cohort of 38 million insurance beneficiaries during the 3-year study period (AAR = 2,086 Rxs per 100,000 beneficiaries). Oral and maxillofacial surgeons prescribed the most antibiotics (1,172,104 Rxs; AAR = 1,018 Rxs per 100,000 beneficiaries), followed by periodontists (527,038 Rxs; AAR = 457 Rxs per 100,000 beneficiaries), and endodontists (447,362 Rxs; AAR = 388 Rxs per 100,000 beneficiaries). Longitudinal antibiotic prescribing trends were stable among all dental specialties in the regression models (P > .05). The authors observed substantial seasonal variation in antibiotic Rxs in 2 specialties: pediatric dentistry (PTTR, 1.18; 95% confidence interval, 1.13 to 1.25) and orthodontics and dentofacial orthopedics (PTTR, 1.41; 95% confidence interval, 1.21 to 1.71), with the highest rates of antibiotic Rxs in the spring and winter. Conclusions Antibiotic prescribing practices for dental specialists remained stable. The authors observed seasonal trends in 2 specialties. Practical Implications Public health efforts are needed improve antibiotic prescribing among dental specialties

Presence of Symptoms 6 Weeks After COVID-19 Among Vaccinated and Unvaccinated US Healthcare Personnel: A Prospective Cohort Study

OBJECTIVES: Although COVID-19 vaccines offer protection against infection and severe disease, there is limited information on the effect of vaccination on prolonged symptoms following COVID-19. Our objective was to determine differences in prevalence of prolonged symptoms 6 weeks after onset of COVID-19 among healthcare personnel (HCP) by vaccination status, and to assess differences in timing of return to work. DESIGN: Cohort analysis of HCP with COVID-19 enrolled in a multicentre vaccine effectiveness study. HCP with COVID-19 between December 2020 and August 2021 were followed up 6 weeks after illness onset. SETTING: Health systems in 12 US states. PARTICIPANTS: HCP participating in a vaccine effectiveness study were eligible for inclusion if they had laboratory-confirmed symptomatic SARS-CoV-2 with mRNA vaccination (symptom onset ≥14 days after two doses) or no prior vaccination. Among 681 eligible participants, 419 (61%) completed a follow-up survey to assess symptoms reported 6 weeks after illness onset. EXPOSURES: Two doses of a COVID-19 mRNA vaccine compared with no COVID-19 vaccine. MAIN OUTCOME MEASURES: Prevalence of symptoms 6 weeks after onset of COVID-19 illness and days to return to work. RESULTS: Among 419 HCP with COVID-19, 298 (71%) reported one or more COVID-like symptoms 6 weeks after illness onset, with a lower prevalence among vaccinated participants compared with unvaccinated participants (60.6% vs 79.1%; adjusted risk ratio 0.70, 95% CI 0.58 to 0.84). Following their illness, vaccinated HCP returned to work a median 2.0 days (95% CI 1.0 to 3.0) sooner than unvaccinated HCP (adjusted HR 1.37, 95% CI 1.04 to 1.79). CONCLUSIONS: Receipt of two doses of a COVID-19 mRNA vaccine among HCP with COVID-19 illness was associated with decreased prevalence of COVID-like symptoms at 6 weeks and earlier return to work