Variable Period Research Articles

LDL-C target attainment and statin use in patients with ASCVD, familial hypercholesterolaemia, and those otherwise at moderate/high-risk of ASCVD in australian general practice (SCOPE-GP)

Abstract Background The proportion of Australian general practice patients not attaining low-density lipoprotein cholesterol (LDL-C) goals is not well described. The SCOPE-GP study evaluated duration of LDL-C exceeding treatment goals, statin use and discontinuation rates in patients with atherosclerotic cardiovascular disease (ASCVD), without ASCVD events but at moderate/high-risk, and familial hypercholesterolemia (FH). Methods This population-based retrospective cohort study used de-identified medical records of adult patients captured in the IQVIA GP-EMR database. Patients were indexed at the earliest date of ASCVD, FH, or hyperlipidemia diagnosis from January 1, 2010 to June 30, 2022, with a variable follow-up period from index to June 30, 2022. Ascertainment of study cohort was based on the 2021 ESC/EAS guidelines and Framingham Risk Equation. LDL-C test result levels were extracted per patient, summarised and analysed. Patients were stratified based on their test results at latest results/closest to censor date. Average time above target levels is the proportion of number of days above LDL-C target levels over total number of follow-up days for each patient. A Poisson distribution was fitted to estimate 95% confidence interval. Lipid lowering therapies (LLT) were stratified by (ASCVD, FH and moderate/high risk of CVD) at last visit/censor date. Combination of LLT were defined as prescriptions for fixed dose combinations or ≥2 separate scripts of LLT from different classes within 180 days from last visit/censor date (look back period). Discontinuation is defined as no statins were prescribed again after the last script for 270 days or more, limited to the first occurrence. Results The average time with LDL-C levels above target was 1077.5 days in ASCVD patients (n=2,688), 938.6 days in moderate-risk ASCVD (n=37,003), 980.9 days in high-risk ASCVD (n=85,199), and 900.8 days in FH (n=279). The proportion of days above target level for all four cohorts is described in Figure 1. Among 107,552 patients with recorded LDL-C levels ≥1.8mmol/L at their last visit/censor date, 30.9% were on statin monotherapy and 1.0% were on statin+ezetimibe. Statin use was highest in ASCVD patients (65.4%), followed by FH (49.5%), high risk (40.0%) and moderate risk subjects (29.5%) (Table 1). Statin discontinuation rates were 60.3%, 76.3, 66.1%, and 65.8% in these groups, respectively. The predominant reason for statin discontinuation was non-specific adverse drug reactions (12.2% ASCVD, 11.7% moderate-risk, 13.2% high-risk and 17.9% FH). The proportion of subjects contraindicated to statins was highest in moderate risk subjects (0.05%). Conclusions Prolonged periods of elevated LDL-C and high statin discontinuation rates were prevalent among at-risk individuals in Australian primary care. This underscores a significant ASCVD burden that could be prevented with more active lipid management.

Analyzing the Maharashtra Ambulance Service “108”: The Prospect and Challenges

ABSTRACT The utilization of digital health in India is playing a crucial role in enhancing healthcare services by transitioning from the current inadequate public health structure to a more efficient and patient-centric system. Digital health includes various digital tools, such as electronic health records (EHRs), telemedicine, mobile health applications, health information exchange systems, and other technological advancements to improve access, efficiency, and quality of healthcare delivery. This study investigates the prospects and challenges encountered by the newly-digitized Maharashtra Emergency Medical Services (MEMS). Utilizing the 38,823 MEMS calls from November 2022, this study investigates the current status of emergency service delivery mechanisms in Maharashtra. Through spatial analyses, this study also explores the causes behind calls. The findings of the study show that calls for 108 ambulance services were distributed across the districts and had variable service delivery time periods. Current challenges to the system arise from various urban and healthcare infrastructure problems, as well as socio-cultural challenges. Implementation of the digitized MEMS system reveals key factors that influence the service’s success, assisting the policymakers and health administrators in identifying and further improving the service.

Influence of quasi-biennial oscillations (QBO) on the stratospheric polar vortex in the Antarctic

For many years, the dominant opinion in the literature has been that the stratospheric polar vortex is weaker in the easterly phase of the QBO than in the westerly phase, which is known as the Holton–Tan effect. While for the Northern Hemisphere vortex this is true during winter, for the Southern Hemisphere vortex the dependence on the QBO is observed only in spring. This feature is usually explained by the greater intensity of the Southern Hemisphere vortex compared to the Northern Hemisphere vortex, and the QBO can modulate its strength only during the vortex breaking season in October-November. Usually, the vortex response to the QBO is determined based on the equatorial wind direction at a certain vertical level, and the conclusions depend strongly on the level at which the QBO phase is determined. However, it has long been shown that using the equatorial wind sign at one or even a combination of several levels is not quite correct because it does not take into account the time of descent of the QBO wind relative to the seasons of the year, and it is not known at what altitudes the QBO wind has the strongest influence on the extratropical stratosphere. Due to the variable period of the QBO cycles, the phase relationship between the seasonal cycle and the QBO cycle is constantly changing, resulting in many variants of the vertical structure of the wind QBO during the Antarctic winter vortex and ozone hole. However, the seasonal regularities of QBO used in this work lead to a strictly limited number of possible variants of coincidence of the phases of the QBO cycles with the seasons of the year, which allows us to reveal typical features of interannual variations of the polar vortex and ozone hole in the Antarctic that are due to the QBO. The analysis of observational data indicates unexpected peculiarities of the QBO modulation of the stratospheric polar vortex in the Antarctic. The QBO effect in the vortex intensity is observed not only in spring during the weakening phase of the winter vortex, but also during the vortex maximum in June–August. At the same time, changes in the wind speed of the vortex during its maximum in winter are opposite to those in the spring during the ozone hole period. If the winter vortex is more intense (weak), then during the ozone hole period the vortex is weaker (more intense) than the average level.

Identification of fractional order time delay system with measurement noise using variable period integration operational matrix

This paper proposes a parameter identification method for fractional-order time-delay systems with measurement noise, based on the Legendre wavelet variable-period integration operational matrix. A variable-period integration operational matrix and a variable-period time-delay integration operational matrix are constructed by variable-period sampling principle. For the impulse noise, global Gaussian noise and local Gaussian noise present in the identification data, the variable-period sampling, operational matrix global coefficient decomposition and matrix local coefficient decomposition methods are used to reconstruct the variable-period integration operational matrix to separate the noise from the data; the fractional-order time-delay system is expressed as an integral equation by using the reconstructed variable-period operational matrix, this reduces the influence of measurement noise on system identification accuracy. To further improve the parameter identification accuracy, the integral equation is solved by the multi-innovation least squares algorithm. The proposed method’s effectiveness is verified through several simulations and an experimental study of a constant-temperature system.

Suggested magnetic braking prescription derived from field complexity fails to reproduce the cataclysmic variable orbital period gap

Magnetic wind braking drives the spin-down of low-mass stars and the evolution of most interacting binary stars. A magnetic braking prescription that was claimed to reproduce both the period distribution of cataclysmic variables (CVs) and the evolution of the rotation rates of low-mass stars is based on a relation between the angular momentum loss rate and magnetic field complexity. The magnetic braking model based on field complexity has been claimed to predict a detached phase that could explain the observed period gap in the period distribution of but has never been tested in detailed models of evolution. Here we fill this gap. We incorporated the suggested magnetic braking law in MESA and simulated the evolution of for different initial stellar masses and initial orbital periods. We find that the prescription for magnetic braking based on field complexity fails to reproduce observations of The predicted secondary star radii are smaller than measured, and an extended detached phase that is required to explain the observed period gap (a dearth of non-magnetic with periods sim 2$ and $ sim 3$ hours ) is not predicted. Proposed magnetic braking prescriptions based on a relation between the angular momentum loss rate and field complexity are too weak to reproduce the bloating of donor stars in derived from observations and, in contrast to previous claims, do not provide an explanation for the observed period gap. The suggested steep decrease in the angular momentum loss rate does not lead to detachment. Stronger magnetic braking prescriptions and a discontinuity at the fully convective boundary are needed to explain the evolution of close binary stars that contain compact objects. The tension between braking laws derived from the spin-down of single stars and those required to explain and other close binaries containing compact objects remains.

Novel applications of linked administrative data – adding longitudinal capability and additional variables to a nationally representative survey of an indigenous population.

Can linked administrative data be used to transform New Zealand's only sample survey on indigenous wellbeing into a longitudinal study? This project extends the usefulness of an important survey dataset by linkage to admin data, effectively adding longitudinal capability within a linked administrative data source. This created robust statistical processes to transform an official statistics survey into a nationally representative cohort study. NZ's Integrated Data Infrastructure (IDI) is a research database of administrative and survey datasets containing a range of variables linkable at the individual level. Te Kupenga is a large nationally representative post-censal survey of NZ's indigenous population (Māori) and is the only official survey with Māori culturally-informed variables. However, it is under-utilised in research. The Te Kupenga survey was used as a foundational cohort linking to outcomes and determinants in different datasets at different time periods. Outcomes included hospitalisations and COVID-19 vaccinations, while determinants included individual, household and geographic variables. Linking a representative survey to admin data created issues of loss to follow-up and missing data, so the original sample is not maintained after linkage. Loss to follow-up and missingness differed depending on variable selection and time periods. So, new universally applicable weights were not possible. However, we created a robust, generally applicable process for re-weighting survey data to account for missingness and loss to follow-up in admin data. This project demonstrates the approach for turning a sample survey into a longitudinal cohort using admin data and creates methods that can be used for other official statistics surveys.

Internal regulatory technology (RegTech) and bank liquidity risk: evidence from Chinese listed banks

ABSTRACT We examine the effect of internal regulatory technology (RegTech) on bank liquidity risk. Based on a dataset of Chinese listed banks from 2015 to 2022, we initially employ a text-mining method to build the internal RegTech index from the banks’ annual reports. We subsequently reveal a significant mitigation effect of internal RegTech on bank liquidity risk. The finding remains robust after alleviating the endogeneity issue and under alternative proxy of the dependent variable and different sample periods. A possible channel is that internal RegTech boosts the regulatory capability and mitigates banks’ risky behaviours. Moreover, our results demonstrate some heterogeneities across RegTech subindices. The compliance and technological foundations subindices are more profound in affecting bank liquidity risk. The findings provide valuable implications for financial regulators regarding the adoption of RegTech.

Polarization‐Induced Buildup and Switching Mechanisms for Soliton Molecules Composed of Noise‐Like‐Pulse Transition States

AbstractBuildup and switching mechanisms of solitons in complex nonlinear systems are fundamentally important dynamical regimes. Using a novel strongly nonlinear optical system, including saturable absorber metal‐organic framework (MOF)‐253@Au and a polarization controller (PC), the work reveals a new buildup scenario for “soliton molecules (SMs)”, which includes a long‐duration stage dominated by the emergence of transient noise‐like pulses (NLPs) modes to withstand strong disturbances arising from “turbulence” and extreme nonlinearity in the optical cavity. The switching between SMs and NLPs is controlled by the cavity polarization state. The switching involves the spectral collapse, following spectral oscillations with a variable period, and self‐organization of NLPs, following energy overshoot. This switching mechanism applies to various patterns with single, paired, and clustered pulses. In the multi‐pulses stage, XPM (cross‐phase‐modulation)‐induced interactions between solitons facilitate a specific mode of energy exchange between them, proportional to interaction duration, ensuring pulse stability during and after state transitions. Systematic simulations reveal the effects of the PC's rotation angle and intra‐cavity nonlinearity on the periodic phase transitions between the different soliton states and accurately reproduce the experimentally observed buildup and switching mechanisms. These findings can enhance the fundamental study and points to potential uses in designing information encoding systems.

COVID-19 severity detection using chest X-ray segmentation and deep learning

COVID-19 has resulted in a significant global impact on health, the economy, education, and daily life. The disease can range from mild to severe, with individuals over 65 or those with underlying medical conditions being more susceptible to severe illness. Early testing and isolation are vital due to the virus’s variable incubation period. Chest radiographs (CXR) have gained importance as a diagnostic tool due to their efficiency and reduced radiation exposure compared to CT scans. However, the sensitivity of CXR in detecting COVID-19 may be lower. This paper introduces a deep learning framework for accurate COVID-19 classification and severity prediction using CXR images. U-Net is used for lung segmentation, achieving a precision of 0.9924. Classification is performed using a Convulation-capsule network, with high true positive rates of 86% for COVID-19, 93% for pneumonia, and 85% for normal cases. Severity assessment employs ResNet50, VGG-16, and DenseNet201, with DenseNet201 showing superior accuracy. Empirical results, validated with 95% confidence intervals, confirm the framework’s reliability and robustness. This integration of advanced deep learning techniques with radiological imaging enhances early detection and severity assessment, improving patient management and resource allocation in clinical settings.

Impact of deficit irrigation and planting density on grain yield and water productivity of maize grown under temperate continental climatic conditions

Variable frequent drought periods in Vojvodina region (the southeastern part of the Pannonian Plain, Serbia), severely limit maize (Zea mays L.) production under rainfed conditions. A four-year field experiment was conducted to investigate the effects of sprinkler deficit irrigation and plant density on yield and water use efficiency of maize grown on silty clay loam soil under temperate continental climate. The experiment included fully irrigated crop (I1), three deficit irrigation treatments (I2, I3 and I4 corresponding to 80, 50 and 40 % of crop evapontranspiration, respectively) and non-irrigated treatment (I0), and three plant densities (LPD: 54,900 plants ha–1; MPD: 64,900 plants ha–1; HPD: 75,200 plants ha–1) in four replicates. The results showed that grain yield, CWP (crop water productivity) and IWP (irrigation water productivity) varied significantly with irrigation amounts, plant densities and seasons. The irrigation rates and plant density interact significantly. MPD and HPD differed significantly from LPD in almost all seasons. With increasing irrigation and plant density, yield and CWP showed an increasing trend. The relative values of IWP increased with the rise of plant density and decreased with the amount of irrigation. The highest four-year average yield (15.03 t ha–1) was obtained in the I1-HPD treatment, while the lowest (9.30 t ha–1) was obtained in the I0-HPD treatment. The highest average values of CWP and IWP were recorded at I3-HPD or/and I2-HPD. The lowest CWP and IWP values were determined for I4-HPD and I4-MPD, respectively. In the pedo-climatic conditions of Vojvodina and similar regions, we recommend growing maize under the I1-HPDtreatment to achieve high yields. Under the water shortage conditions, the application of I2-HPD treatment is a favorable strategy saving 37 % of irrigation water, while reducing maize grain yield by ∼10 %.

Assessing vaccine efficacy for infectious diseases with variable immunity using a mathematical model

This study introduces an SIRS compartmental mathematical model encompassing vaccination and variable immunity periods for infectious diseases. I derive a basic reproduction number formula and assess the local and global stability of disease-free and the local stability of the endemic equilibria. I demonstrate that the basic reproduction number in the presence of a vaccine is highly sensitive to the rate of immunity loss, and even a slight reduction in this rate can significantly contribute to disease control. Additionally, I have derived a formula to calculate the critical efficacy period required for a vaccine to effectively manage and control the disease.The analysis conducted for the model suggests that increasing the vaccine’s immunity duration (efficacy) decelerates disease dynamics, leading to reduced rates of reinfection and less severe disease outcomes. Furthermore, this delay contributes to a decrease in the basic reproduction number (R0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R_0$$\\end{document}), thus facilitating more rapid disease control efforts.

Impact of standardized care guidelines featuring next-day discharge on outcome, healthcare consumption, and patient healthcare experience in patients with idiopathic normal pressure hydrocephalus receiving ventriculoperitoneal shunts.

The aim of this study was to evaluate the effect of standardized care guidelines featuring next-day discharge on hospital length of stay (LOS), outcomes, patient experience, and healthcare consumption in patients receiving ventriculoperitoneal shunts (VPSs) for idiopathic normal pressure hydrocephalus (iNPH). This single-center population-based observational cohort study included 271 adult iNPH patients who underwent VPS surgery at Karolinska University Hospital. Groups were compared before and after the implementation of new standardized discharge guidelines. The primary outcome was the hospital LOS. Secondary outcomes included postoperative complications, patient experience, and frequency of unscheduled outpatient follow-up appointments. A total of 121 patients were treated with variable hospitalization periods. One hundred fifty patients were managed under the new guidelines stipulating next-day discharge. There was no significant difference in positive surgical outcome (66% vs 71%, p = 0.372) or rates of complication (p ≥ 0.066) between groups. The standardized guidelines group had a significantly shorter period of inpatient hospitalization (1 vs 2 days, p < 0.001) and demonstrated lower levels of unscheduled outpatient healthcare consumption (p < 0.001) while maintaining levels of positive patient experience (p = 0.828). Standardized discharge guidelines featuring next-day discharge are safe for iNPH patients undergoing VPS surgery, maintain the quality of the patient experience, and are an effective method for mitigating healthcare consumption in an expanding patient group.

Water quality and wetland vegetation responses to water level variations in a university stormwater reuse reservoir: Nature-based approaches to campus water sustainability

In response to climate-driven water shortages, Duke University in 2014 constructed a water reuse reservoir and wetland complex (Pond) to capture urban stormwater and recycle water to provide campus cooling and reduce downstream loading of nutrients and sediment into Jordan Lake, a regional water supply. We postulated that even with significant water level changes due to withdrawals, the Pond would function to reduce downstream nutrients and sediment once wetland plants became established in the littoral zone. Throughout the project (2015–2021), baseflow nutrient concentrations downstream decreased, with Unfiltered Total Nitrogen (UTN) falling by 44 % and Unfiltered Total Phosphorus (UTP) by 50 %. Storm mean concentrations decreased by 31 % for UTN, 54 % for UTP, and 72 % for Total Suspended Solids (TSS). The annual reductions in mass fluxes (UTN, UTP, and TSS) were between 58 and 85 % across a range of storm intensities. Regardless of water level, temperature, pH, and oxygen concentrations downstream were not significantly changed. Between 2015 and 2020, a littoral survey of planted and naturally introduced species showed that wetter years resulted in a greater number of species across a gradient of three inundation zones (i.e., moist, wet, and aquatic). Conversely, dryer years resulted in fewer species across overlapping zones. The dominant plants that successfully colonized the Pond are all obligate wetland species despite the Pond's highly variable water depths and periods of inundation. The final plant populations were dominated by invasive native species supporting the self-design theory of plant succession as nearly half of the original planted species died. The reuse Pond design (pond-wetland complex) showed the capability of using stormwater runoff for campus cooling while improving water quality services and providing habitat for wetland plants. Thus, campuses with watershed runoff capture capability should consider a nature-based recycling approach as part of their water sustainability program.

Real-world unified airway benefits of mepolizumab: Effectiveness in patients with asthma and comorbid nasal polyps

BackgroundNasal polyps (NPs) are commonly associated with chronic rhinosinusitis (CRS). In keeping with the unified airway hypothesis, asthma and CRS with NP (CRSwNP) frequently co-occur, share a similar pathophysiology, and are often treated with oral corticosteroids (OCS); however, a need for alternative treatment options for patients with comorbid asthma and CRSwNP remains. ObjectiveTo characterize the short- and long-term dual airway effectiveness of the anti–interleukin-5 monoclonal antibody, mepolizumab, in real-world patients with asthma and comorbid NP. MethodsAdult patients with CRSwNP who initiated mepolizumab from November 1, 2014, to September 30, 2021, were identified from 2 Merative MarketScan Research Databases. Outcomes were compared for the 12 months pre- and post-mepolizumab initiation and a variable follow-up period. Primary outcomes included the following: annual rate and proportion of patients with NP- and asthma-related exacerbations; NP surgery occurrences; all-cause OCS claims, number of OCS bursts, and daily OCS dose; all-cause and NP-related health care resource utilization. ResultsDuring the 12 months post-index, patients experienced fewer NP- and asthma-related exacerbations, required fewer sinus surgeries, and reduced use of OCS, with fewer all-cause OCS claims and OCS bursts. Significant reductions in asthma exacerbation-related and NP-related health care resource utilization were also observed. ConclusionThis study illustrated the near- and long-term real-world effectiveness of mepolizumab treatment, with a focus on dual lower and upper airway benefit from single-agent add-on therapy. These results may aid physicians in clinical decision-making for patients with asthma and comorbid CRSwNP with complex care needs.

Intermittent swimming and muscle power output in brook trout, Salvelinus fontinalis.

Slow and sustainable intermittent swimming has recently been described in several Centrarchid fishes, such as bluegill and largemouth bass. This swimming behavior involves short periods of body-caudal fin undulation alternating with variable periods of coasting. This aerobic muscle powered swimming appears to reduce energetic costs for slow, sustainable swimming, with fish employing a "fixed-gear" or constant tailbeat frequency and modulating swimming speed by altering the length of the coasting period. We asked if this swimming behavior was found in other fish species by examining volitional swimming by brook trout in a static swimming tank. Further, we employed muscle mechanics experiments to explore how intermittent swimming affects muscle power output in comparison to steady swimming behavior. Brook trout regularly employ an intermittent swimming form when allowed to swim volitionally, and consistently showed a tailbeat frequency of ~2 Hz. Coasting duration had a significant, inverse relationship to swimming speed. Across a range of slow, sustainable swimming speeds, tailbeat frequency increased modestly with speed. The duration of periods of coasting decreased significantly with increasing speed. Workloop experiments suggest that intermittent swimming reduces fatigue, allowing fish to maintain high power output for longer compared to continuous activity. This study expands the list of species that employ intermittent swimming, suggesting this behavior is a general feature of fishes.

Synthetic and practical reconstructions of SST and seawater pH using the novel multiproxy SMITE method.

Geochemical proxies of sea surface temperature (SST) and seawater pH (pHsw) in scleractinian coral skeletons are valuable tools for reconstructing tropical climate variability. However, most coral skeletal SST and pHsw proxies are univariate methods that are limited in their capacity to circumvent non-climate-related variability. Here we present a novel multivariate method for reconstructing SST and pHsw from the geochemistry of coral skeletons. Our Scleractinian Multivariate Isotope and Trace Element (SMITE) method optimizes reconstruction skill by leveraging the covariance across an array of coral elemental and isotopic data with SST and pHsw. First, using a synthetic proxy experiment, we find that SMITE SST reconstruction statistics (correlation, accuracy, and precision) are insensitive to noise and variable calibration period lengths relative to Sr/Ca. While SMITE pHsw reconstruction statistics remain relative to δ11B throughout the same synthetic experiment, the magnitude of the long-term trend in pHsw is progressively lost under conditions of moderate-to-high analytical uncertainty. Next, we apply the SMITE method to an array of seven coral-based geochemical variables (B/Ca, δ11B, Li/Ca, Mg/Ca, Sr/Ca, U/Ca & Li/Mg) measured from two Bermudan Porites astreoides corals. Despite a <3.5 year calibration period, SMITE SST and pHsw estimates exhibit significantly better accuracy, precision, and correlation with their respective climate targets than the best single- and dual-proxy estimators. Furthermore, SMITE model parameters are highly reproducible between the two coral cores, indicating great potential for fossil applications (when preservation is high). The results shown here indicate that the SMITE method can outperform the most common coral-based SST and pHsw reconstructions methods to date, particularly in datasets with a large variety of geochemical variables. We therefore provide a list of recommendations and procedures for users to begin implementing the SMITE method as well as an open-source software package to facilitate dissemination of the SMITE method.

Evaluation of distribution system water quality during a free chlorine conversion.

Chloraminated drinking water systems commonly use free chlorine conversions (FCCs) to prevent or control nitrification, but unintended water quality changes may occur, including increased disinfection by-product and metal concentrations. This study evaluated water quality in a chloraminated drinking water system and residential locations before, during, and after their annual, planned FCC. Water quality alternated between relatively consistent and variable periods when switching disinfectants. During the FCC, regulated four trihalomethane and five haloacetic acid concentrations increased by four and seven times, respectively, and exceeded corresponding maximum contaminant levels. Implications of disinfection by-product sampling during an FCC were assessed, and an approach to account for increased FCC disinfection by-product concentrations was proposed. For metals, the FCC had minor impacts on distribution system concentrations and did not appear to impact residential concentrations. Overall, observed variable water quality appeared primarily associated with switching disinfectants and depended on distribution system hydraulics.

Digestive and breast cancer patients managed during the first wave of COVID-19 pandemic: Short and middle term outcomes.

The first wave of coronavirus disease 2019 (COVID-19) pandemic in Spain lasted from middle March to the end of June 2020. Spanish population was subjected to lockdown periods and scheduled surgeries were discontinued or reduced during variable periods. In our centre, we managed patients previously and newly diagnosed with cancer. We established a strategy based on limiting perioperative social contacts, preoperative screening (symptoms and reverse transcription-polymerase chain reaction) and creating separated in-hospital COVID-19-free pathways for non-infected patients. We also adopted some practice modifications (surgery in different facilities, changes in staff and guidelines, using continuously changing personal protective equipment…), that supposed new inconveniences. To analyse cancer patients with a decision for surgery managed during the first wave, focalizing on outcomes and pandemic-related modifications. We prospectively included adults with a confirmed diagnosis of colorectal, oesophago-gastric, liver-pancreatic or breast cancer with a decision for surgery, regardless of whether they ultimately underwent surgery. We analysed short-term outcomes [30-d postoperative morbimortality and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection] and outcomes after 3 years (adjuvant therapies, oncological events, death, SARS-CoV-2 infection and vaccination). We also investigated modifications to usual practice. From 96 included patients, seven didn't receive treatment that period and four never (3 due to COVID-19). Operated patients: 28 colon and 21 rectal cancers; laparoscopy 53.6%/90.0%, mortality 3.57%/0%, major complications 7.04%/25.00%, anastomotic leaks 0%/5.00%, 3-years disease-free survival (DFS) 82.14%/52.4% and overall survival (OS) 78.57%/76.2%. Six liver metastases and six pancreatic cancers: no mortality, one major complication, three grade A/B liver failures, one bile leak; 3-year DFS 0%/33.3% and OS 50.0%/33.3% (liver metastases/pancreatic carcinoma). 5 gastric and 2 oesophageal tumours: mortality 0%/50%, major complications 0%/100%, anastomotic leaks 0%/100%, 3-year DFS and OS 66.67% (gastric carcinoma) and 0% (oesophagus). Twenty breast cancer without deaths/major complications; 3-year OS 100% and DFS 85%. Nobody contracted SARS-CoV-2 postoperatively. COVID-19 pandemic-related changes: 78.2% treated in alternative buildings, 43.8% waited more than 4 weeks, two additional colostomies and fewer laparoscopies. Some patients lost curative-intent surgery due to COVID-19 pandemic. Despite practice modifications and 43.8% delays higher than 4 weeks, surgery was resumed with minimal changes without impacting outcomes. Clean pathways are essential to continue surgery safely.

Analysis of wake and power fluctuation of a tidal current turbine under variable wave periods

In the Marine environment, waves and turbulence usually coexist, affecting the operation performance of the tidal current energy turbine. This paper conducts experiments on a scaled tidal stream turbine to study the wave period effect on the wake and power characteristics. Under a wave-current environment, the wake is found to display Gaussian distribution. Within the 4 times diameter downstream range (4D), the turbulence is significant, and both the wake velocity loss and fluctuation increase first and then decrease with wave period. After 6D, the flow field gradually recovers to the inflow level. The wave period affects the transversal turbulence, more in the near than far wake region, as the significant turbulence intensities at the hub and blade tips gradually merge and become consistent after 6D. The wave period affects little the power coefficient CP owing to the sinusoidal inflow velocity nature. However, the amplitude of the phase average power increases first and then decreases with the wave period. By contrast, the phase average power fluctuations are sensitive to cycle changes only within the low TSR interval; they decrease sharply with TSR. In addition, the energy distribution of power fluctuation in the wave flow coupling environment is mainly concentrated at the sum and difference, and as well multiples, of the rotational and wave frequency. The wave and its multiples energy distribution increases and then decreases with the wave period.

Magnetic braking below the cataclysmic variable period gap and the observed dearth of period bouncers

Period bouncers are cataclysmic variables (CVs) that have evolved past their orbital period minimum. The strong disagreement between theory and observations of the relative fraction of period bouncers is a severe shortcoming in the understanding of CV evolution. We test the implications of the hypothesis that magnetic braking (MB), which is suggested to be an additional angular momentum loss (AML) mechanism for CVs below the period gap ($P_ orb 120$ min), weakens around their period minimum. We computed the evolution of CV donors below the period gap using the MESA code, assuming that the evolution of the system is driven by AML black due to gravitational wave radiation (GWR) and MB. We parametrised the MB strength as $ AML_ MB AML_ GWR black We computed two qualitatively different sets of models, one in which kappa is a constant and another in which kappa depends on stellar parameters in such a way that the value of kappa decreases as the CV approaches the period minimum ($P_ orb min), beyond which $ approx0$. We find that black two crucial effects drive the latter set of models. (1) A decrease in kappa as CVs approach the period minimum stalls their evolution so that they spend a long time in the observed period minimum spike ($80 P_ orb min Here, they become difficult to distinguish from pre-bounce systems in the spike. (2) A strong decrease in the mass-transfer rate makes them virtually undetectable as they evolve further. So, the CV stalls around the period minimum and then `disappears'. This reduces the number of detectable bouncers. Physical processes, such as dynamo action, white dwarf magnetism, and dead zones, may cause such a weakening of MB at short orbital periods. The weakening MB formalism black provides a possible solution to the problem of the dearth of black detectable period bouncers in CV observational surveys.