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32,277 result(s) for "duration"
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Sleep duration and health outcomes: an umbrella review
PurposeTo collect existing evidence on the relationship between sleep duration and health outcomes.MethodsA thorough search was conducted in PubMed, Web of Science, Embase, and the Cochrane Database of Systematic Reviews from inception to January, 2021. Meta-analyses of observational and interventional studies were eligible if they examined the associations between sleep duration and human health.ResultsIn total, this umbrella review identified 69 meta-analyses with 11 outcomes for cancers and 30 outcomes for non-cancer conditions. Inappropriate sleep durations may significantly elevate the risk for cardiovascular disease (CVD), cognitive decline, coronary heart disease (CHD), depression, falls, frailty, lung cancer, metabolic syndrome (MS), and stroke. Dose–response analysis revealed that a 1-h reduction per 24 hours is associated with an increased risk by 3–11% of all-cause mortality, CHD, osteoporosis, stroke, and T2DM among short sleepers. Conversely, a 1-h increment in long sleepers is associated with a 7–17% higher risk of stroke mortality, CHD, stroke, and T2DM in adults.ConclusionInappropriate sleep duration is a risk factor for developing non-cancer conditions. Decreasing and increasing sleep hours towards extreme sleep durations are associated with poor health outcomes.
The Project Scheduling Problem with Non-Deterministic Activities Duration: A Literature Review
Purpose: The goal of this article is to provide an extensive literature review of the models and solution procedures proposed by many researchers interested on the Project Scheduling Problem with nondeterministic activities duration. Design/methodology/approach: This paper presents an exhaustive literature review, identifying the existing models where the activities duration were taken as uncertain or random parameters. In order to get published articles since 1996, was employed the Scopus database. The articles were selected on the basis of reviews of abstracts, methodologies, and conclusions. The results were classified according to following characteristics: year of publication, mathematical representation of the activities duration, solution techniques applied, and type of problem solved. Findings: Genetic Algorithms (GA) was pointed out as the main solution technique employed by researchers, and the Resource-Constrained Project Scheduling Problem (RCPSP) as the most studied type of problem. On the other hand, the application of new solution techniques, and the possibility of incorporating traditional methods into new PSP variants was presented as research trends. Originality/value: This literature review contents not only a descriptive analysis of the published articles but also a statistical information section in order to examine the state of the research activity carried out in relation to the Project Scheduling Problem with non-deterministic activities duration.
Sub-2-cycle multi-mJ single-stage post-compression in a multipass cell
We report on the nonlinear temporal compression of multi-mJ pulses from a commercial Ti:Sa laser in a gas-filled multipass cell down to a record pulse duration of 4 fs with 60% overall efficiency.
Statistical Metrics for the Temporal Acoustics of Durationally Contrastive Vocalics: A Proposal Tested with Data from Arabic and Japanese
Previous research has utilized the duration ratio and occasionally the duration difference as single-value metrics to measure and compare the temporal acoustics of durationally contrastive vocalics (short vs. long vowels), which allow researchers to reduce two values (short and long) to one, but express a relationship instead of representing the vocalic duration values directly. The duration ratio may even be misleading when comparing two languages or dialects, as it is possible to exhibit a similar ratio but differ in durational acoustics, or vice versa. The current study proposes two alternative statistical metrics: a duration metric and a difference metric. The duration metric is an intermediate (mean-like) value between the duration of the short and long vocalics, and the difference metric is a ± value that can be added to or subtracted from the duration metric to obtain the duration of long or short vocalics. We conduct a production experiment on Arabic and Japanese vocalics and analyze the data using both traditional measures and the proposed metrics. The findings show that the proposed metrics better predict the language from which the vocalic duration values were obtained. Such results suggest that the proposed metrics are better candidates for measuring and comparing the temporal acoustics of vocalics.
Comparing bias correction methods in downscaling meteorological variables for a hydrologic impact study in an arid area in China
Water resources are essential to the ecosystem and social economy in the desert and oasis of the arid Tarim River basin, northwestern China, and expected to be vulnerable to climate change. It has been demonstrated that regional climate models (RCMs) provide more reliable results for a regional impact study of climate change (e.g., on water resources) than general circulation models (GCMs). However, due to their considerable bias it is still necessary to apply bias correction before they are used for water resources research. In this paper, after a sensitivity analysis on input meteorological variables based on the Sobol' method, we compared five precipitation correction methods and three temperature correction methods in downscaling RCM simulations applied over the Kaidu River basin, one of the headwaters of the Tarim River basin. Precipitation correction methods applied include linear scaling (LS), local intensity scaling (LOCI), power transformation (PT), distribution mapping (DM) and quantile mapping (QM), while temperature correction methods are LS, variance scaling (VARI) and DM. The corrected precipitation and temperature were compared to the observed meteorological data, prior to being used as meteorological inputs of a distributed hydrologic model to study their impacts on streamflow. The results show (1) streamflows are sensitive to precipitation, temperature and solar radiation but not to relative humidity and wind speed; (2) raw RCM simulations are heavily biased from observed meteorological data, and its use for streamflow simulations results in large biases from observed streamflow, and all bias correction methods effectively improved these simulations; (3) for precipitation, PT and QM methods performed equally best in correcting the frequency-based indices (e.g., standard deviation, percentile values) while the LOCI method performed best in terms of the time-series-based indices (e.g., Nash–Sutcliffe coefficient, R2); (4) for temperature, all correction methods performed equally well in correcting raw temperature; and (5) for simulated streamflow, precipitation correction methods have more significant influence than temperature correction methods and the performances of streamflow simulations are consistent with those of corrected precipitation; i.e., the PT and QM methods performed equally best in correcting flow duration curve and peak flow while the LOCI method performed best in terms of the time-series-based indices. The case study is for an arid area in China based on a specific RCM and hydrologic model, but the methodology and some results can be applied to other areas and models.
Effect of Diet on the Gut Microbiota: Rethinking Intervention Duration
The human gut is inhabited by trillions of microorganisms composing a dynamic ecosystem implicated in health and disease. The composition of the gut microbiota is unique to each individual and tends to remain relatively stable throughout life, yet daily transient fluctuations are observed. Diet is a key modifiable factor influencing the composition of the gut microbiota, indicating the potential for therapeutic dietary strategies to manipulate microbial diversity, composition, and stability. While diet can induce a shift in the gut microbiota, these changes appear to be temporary. Whether prolonged dietary changes can induce permanent alterations in the gut microbiota is unknown, mainly due to a lack of long-term human dietary interventions, or long-term follow-ups of short-term dietary interventions. It is possible that habitual diets have a greater influence on the gut microbiota than acute dietary strategies. This review presents the current knowledge around the response of the gut microbiota to short-term and long-term dietary interventions and identifies major factors that contribute to microbiota response to diet. Overall, further research on long-term diets that include health and microbiome measures is required before clinical recommendations can be made for dietary modulation of the gut microbiota for health.
Comparison of high‐power short‐duration and low‐power long‐duration radiofrequency ablation for treating atrial fibrillation: Systematic review and meta‐analysis
Background High power shorter duration (HPSD) ablation seen to increase efficacy and safety treating of atrial fibrillation (AF); however, comparative data between HPSD and low power longer duration (LPLD) ablation are limited. Hypothesis We thought that HPSD might bring more clinical benefits. The aim of this meta‐analysis was to evaluate the clinical benefits of HPSD in patients with AF. Methods The Medline, PubMed, Embase, and the Cochrane Library databases were searched for studies comparing HPSD and LPLD ablation. Results Ten trials with 2467 patients were included in the analysis. Pooled analyses demonstrated that HPSD showed a benefit of first‐pass pulmonary vein isolation (PVI) (risk ratio [RR]: 1.20; 95% confidence interval [CI]: 1.10‐1.31, P < .001) and recurrence of atrial arrhythmias (RR: 0.73; 95% CI: 0.58‐0.91, P = .005). Additionally, HPSD could reduce procedural time (weighted mean difference [WMD]: −42.93; 95% CI, −58.10 to −27.75, P < .001), ablation time (WMD: −21.01; 95% CI: −24.55 to −17.47, P < .001), and fluoroscopy time (WMD: −4.11; 95% CI: −6.78 to −1.45, P < .001). Moreover, major complications and esophageal thermal injury (ETI) were similar between two groups (RR: 0.75; 95% CI: 0.44‐1.30, P = .31) and (RR: 0.57; 95% CI: 0.21‐1.51, P = .26). Conclusions HPSD was safe and efficient for treating AF. Compared with LPLD, HPSD was associated with advantages of procedural features, higher first‐pass PVI and reducing recurrence of atrial arrhythmias. Moreover, major complications and ETI were similar between two groups.
Determination of river flow and sediment regime changes in response to construction of regulating dams: an indicator-based approach
Construction of dams causes changes in the natural flow and sediment patterns of rivers, disrupting their ecosystems. This study aims to evaluate how two dams in Ardabil province affect river flow and sediment load indicators. Several indices, including mean annual flow/sediment load (A), flow/sediment load duration curve difference (M), flow/sediment load duration variability (Dv), and seasonal period (SP), were employed to evaluate the impact of regulatory dams on the monthly flow/sediment regime of the river. Results indicate similar monthly flow and sediment load values at the upstream and downstream stations of Yamchi dam, with a slight increase at the downstream station of Sabalan dam. Yamchi dam had a more substantial impact than Sabalan dam on flow and sediment load indices. Both dams exhibited high seasonal amplitude (SA), signifying significant flow and sediment load variability. The Yamchi dam had more effect on flow index changes, with a flow duration curve difference (M = 0.77). Additionally, the changes in sediment-related indices were greater at Polealmas compared to Doost Bigloo (0.98 vs. 0.8), indicating a reduced sediment-related impact during the study period. The monthly changes in flow and sediment load at the upstream and downstream stations of both dams followed the same pattern. The study emphasizes the different impacts of dams on the flow/sediment load regime of the river, implying varying ecological implications on the river ecosystem and riparian zones. The findings emphasize the importance of considering multiple indicators to comprehensively evaluate dam impacts on river dynamics and underscore the impacts on flow regime and river ecosystem.
Seven Versus 14 Days of Antibiotic Therapy for Uncomplicated Gram-negative Bacteremia
Gram-negative bacteremia is a major cause of morbidity and mortality in hospitalized patients. Data to guide the duration of antibiotic therapy are limited. This was a randomized, multicenter, open-label, noninferiority trial. Inpatients with gram-negative bacteremia, who were afebrile and hemodynamically stable for at least 48 hours, were randomized to receive 7 days (intervention) or 14 days (control) of covering antibiotic therapy. Patients with uncontrolled focus of infection were excluded. The primary outcome at 90 days was a composite of all-cause mortality; relapse, suppurative, or distant complications; and readmission or extended hospitalization (>14 days). The noninferiority margin was set at 10%. We included 604 patients (306 intervention, 298 control) between January 2013 and August 2017 in 3 centers in Israel and Italy. The source of the infection was urinary in 411 of 604 patients (68%); causative pathogens were mainly Enterobacteriaceae (543/604 [90%]). A 7-day difference in the median duration of covering antibiotics was achieved. The primary outcome occurred in 140 of 306 patients (45.8%) in the 7-day group vs 144 of 298 (48.3%) in the 14-day group (risk difference, -2.6% [95% confidence interval, -10.5% to 5.3%]). No significant differences were observed in all other outcomes and adverse events, except for a shorter time to return to baseline functional status in the short-course therapy arm. In patients hospitalized with gram-negative bacteremia achieving clinical stability before day 7, an antibiotic course of 7 days was noninferior to 14 days. Reducing antibiotic treatment for uncomplicated gram-negative bacteremia to 7 days is an important antibiotic stewardship intervention. NCT01737320.