1,523 research outputs found

    The study design of UDRIVE: the Naturalistic Driving Study across Europe for cars, trucks and scooters

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    Purpose: UDRIVE is the first large-scale European Naturalistic Driving Study on cars, trucks and powered two wheelers. The acronym stands for "European naturalistic Driving and Riding for Infrastructure & Vehicle safety and Environment". The purpose of the study is to gain a better understanding of what happens on the road in everyday traffic situations. Methods: The paper describes Naturalistic Driving Studies, a method which provides insight into the actual real-world behaviour of road users, unaffected by experimental conditions and related biases. Naturalistic driving can be defined as a study undertaken to provide insight into driver behaviour during everyday trips by recording details of the driver, the vehicle and the surroundings through unobtrusive data gathering equipment and without experimental control. Data collection will take place in six EU Member States. Results: Road User Behaviour will be studied with a focus on both safety and environment. The UDRIVE project follows the steps of the FESTA-V methodology, which was originally designed for Field Operational Tests. Conclusions: Defining research questions forms the basis of the study design and the specification of the recording equipment. Both will be described in this paper. Although the project has just started collecting data from drivers, we consider the process of designing the study as a major result which may help other initiatives to set up similar studies

    Multi-Regge kinematics and the moduli space of Riemann spheres with marked points

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    We show that scattering amplitudes in planar N = 4 Super Yang-Mills in multi-Regge kinematics can naturally be expressed in terms of single-valued iterated integrals on the moduli space of Riemann spheres with marked points. As a consequence, scattering amplitudes in this limit can be expressed as convolutions that can easily be computed using Stokes' theorem. We apply this framework to MHV amplitudes to leading-logarithmic accuracy (LLA), and we prove that at L loops all MHV amplitudes are determined by amplitudes with up to L + 4 external legs. We also investigate non-MHV amplitudes, and we show that they can be obtained by convoluting the MHV results with a certain helicity flip kernel. We classify all leading singularities that appear at LLA in the Regge limit for arbitrary helicity configurations and any number of external legs. Finally, we use our new framework to obtain explicit analytic results at LLA for all MHV amplitudes up to five loops and all non-MHV amplitudes with up to eight external legs and four loops.Comment: 104 pages, six awesome figures and ancillary files containing the results in Mathematica forma

    Reporting guideline for interventional trials of primary and incisional ventral hernia repair

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    BACKGROUND: Primary and incisional ventral hernia trials collect unstandardized inconsistent data, limiting data interpretation and comparison. This study aimed to create two minimum data sets for primary and incisional ventral hernia interventional trials to standardize data collection and improve trial comparison. To support these data sets, standardized patient-reported outcome measures and trial methodology criteria were created. METHODS: To construct these data sets, nominal group technique methodology was employed, involving 15 internationally recognized abdominal wall surgeons and two patient representatives. Initially a maximum data set was created from previous systematic and panellist reviews. Thereafter, three stages of voting took place: stage 1, selection of the number of variables for data set inclusion; stage 2, selection of variables to be included; and stage 3, selection of variable definitions and detection methods. A steering committee interpreted and analysed the data. RESULTS: The maximum data set contained 245 variables. The three stages of voting commenced in October 2019 and had been completed by July 2020. The final primary ventral hernia data set included 32 variables, the incisional ventral hernia data set included 40 variables, the patient-reported outcome measures tool contained 25 questions, and 40 methodological criteria were chosen. The best known variable definitions were selected for accurate variable description. CT was selected as the optimal preoperative descriptor of hernia morphology. Standardized follow-up at 30 days, 1 year, and 5 years was selected. CONCLUSION: These minimum data sets, patient-reported outcome measures, and methodological criteria have allowed creation of a manual for investigators aiming to undertake primary ventral hernia or incisional ventral hernia interventional trials. Adopting these data sets will improve trial methods and comparisons

    Comparison of patients with severe COVID-19 admitted to an intensive care unit in South Africa during the first and second wave of the COVID-19 pandemic

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    BACKGROUND: The second wave of coronavirus disease 2019 (COVID‑19), dominated by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Beta variant, has been reported to be associated with increased severity in South Africa (SA). OBJECTIVES: To describe and compare clinical characteristics, management and outcomes of COVID‑19 patients admitted to an intensive care unit (ICU) in SA during the first and second waves. METHODS: In a prospective, single-centre, descriptive study, we compared all patients with severe COVID‑19 admitted to ICU during the first and second waves. The primary outcomes assessed were ICU mortality and ICU length of stay (LOS). RESULTS: In 490 patients with comparable ages and comorbidities, no difference in mortality was demonstrated during the second compared with the first wave (65.9% v. 62.5%, p=0.57). ICU LOS was longer in the second wave (10 v. 6 days, p<0.001). More female admissions (67.1% v. 44.6%, p<0.001) and a greater proportion of patients were managed with invasive mechanical ventilation than with non-invasive respiratory support (39.0% v. 14%, p<0.001) in the second wave. CONCLUSIONS: While clinical characteristics were comparable between the two waves, a higher proportion of patients was invasively ventilated and ICU stay was longer in the second. ICU mortality was unchanged

    Meditation on the Soles of the Feet Practice Provides Some Control of Aggression for Individuals with Alzheimer’s Disease

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    Alzheimer’s disease is a progressive neurodegenerative condition that affects cognition, mental and physical health, and functionality of older people. As the disease progresses from the mild to moderate stage, there is a concomitant increase in several behavioral variables, chiefly agitation, anger, and aggression. Currently, there are no evidence-based treatments for these behaviors in this population. Three individuals with moderate Alzheimer’s disease were taught an informal mindfulness practice, meditation on the Soles of the Feet (SoF), as a self-management strategy within a multiple-baseline design across participants. All three were able to learn and use the SoF practice to manage their verbal and physical aggression. Their use of the SoF practice was correlated with decreased perceived psychological stress for their spouses and caregivers, as well as for the participants, but to a much smaller degree. In terms of social validity, the participants, their spouses, and caregivers rated the SoF practice as acceptable, effective, with no unintended effects, and indicated that they would recommend the practice to others. However, they also rated SoF as effortful for the participants because it involves the participants remembering to use the practice with rising anger, a requirement particularly challenging for those with memory problems. The SoF practice may enable individuals in the early stages of dementia to manage their anger and aggression. The data were derived from an internally valid experimental design, suggestive of initial proof-of-concept, but needs to be replicated before any clinical implications can be imputed from this study

    Definitions for Loss of Domain: An International Delphi Consensus of Expert Surgeons

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    BACKGROUND: No standardized written or volumetric definition exists for 'loss of domain' (LOD). This limits the utility of LOD as a morphological descriptor and as a predictor of peri- and postoperative outcomes. Consequently, our aim was to establish definitions for LOD via consensus of expert abdominal wall surgeons. METHODS: A Delphi study involving 20 internationally recognized abdominal wall reconstruction (AWR) surgeons was performed. Four written and two volumetric definitions of LOD were identified via systematic review. Panelists completed a questionnaire that suggested these definitions as standardized definitions of LOD. Consensus on a preferred term was pre-defined as achieved when selected by ≥80% of panelists. Terms scoring <20% were removed. RESULTS: Voting commenced August 2018 and was completed in January 2019. Written definition: During Round 1, two definitions were removed and seven new definitions were suggested, leaving nine definitions for consideration. For Round 2, panelists were asked to select all appealing definitions. Thereafter, common concepts were identified during analysis, from which the facilitators advanced a new written definition. This received 100% agreement in Round 3. Volumetric definition: Initially, panelists were evenly split, but consensus for the Sabbagh method was achieved. Panelists could not reach consensus regarding a threshold LOD value that would preclude surgery. CONCLUSIONS: Consensus for written and volumetric definitions of LOD was achieved from 20 internationally recognized AWR surgeons. Adoption of these definitions will help standardize the use of LOD for both clinical and academic activities

    Uncoupling protein-1 (UCP1) contributes to the basal proton conductance of brown adipose tissue mitochondria

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    Proton leak pathways uncouple substrate oxidation from ATP synthesis in mitochondria. These pathways are classified as basal (not regulated) or inducible (activated and inhibited). Previously it was found that over half of the basal proton conductance of muscle mitochondria was catalyzed by the adenine nucleotide translocase (ANT), an abundant mitochondrial anion carrier protein. To determine whether ANT is the unique protein catalyst, or one of many proteins that catalyze basal proton conductance, we measured proton leak kinetics in mitochondria isolated from brown adipose tissue (BAT). BAT can express another mitochondrial anion carrier, UCP1, at concentrations similar to ANT. Basal proton conductance was measured under conditions where UCP1 and ANT were catalytically inactive and was found to be lower in mitochondria from UCP1 knockout mice compared to wild-type. Ablation of another abundant inner membrane protein, nicotinamide nucleotide transhydrogenase, had no effect on proton leak kinetics in mitochondria from liver, kidney or muscle, showing that basal proton conductance is not catalyzed by all membrane proteins. We identify UCP1 as a second protein propagating basal proton leak, lending support to the hypothesis that basal leak pathways are perpetrated by members of the mitochondrial anion carrier family but not by other mitochondrial inner membrane proteins

    Simulation studies of age-specific lifetime major depression prevalence

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    BACKGROUND: The lifetime prevalence (LTP) of Major Depressive Disorder (MDD) is the proportion of a population having met criteria for MDD during their life up to the time of assessment. Expectation holds that LTP should increase with age, but this has not usually been observed. Instead, LTP typically increases in the teenage years and twenties, stabilizes in adulthood and then begins to decline in middle age. Proposed explanations for this pattern include: a cohort effect (increasing incidence in more recent birth cohorts), recall failure and/or differential mortality. Declining age-specific incidence may also play a role. METHODS: We used a simulation model to explore patterns of incidence, recall and mortality in relation to the observed pattern of LTP. Lifetime prevalence estimates from the 2002 Canadian Community Health Survey, Mental Health and Wellbeing (CCHS 1.2) were used for model validation and calibration. RESULTS: Incidence rates predicting realistic values for LTP in the 15-24 year age group (where mortality is unlikely to substantially influence prevalence) lead to excessive LTP later in life, given reasonable assumptions about mortality and recall failure. This suggests that (in the absence of cohort effects) incidence rates decline with age. Differential mortality may make a contribution to the prevalence pattern, but only in older age categories. Cohort effects can explain the observed pattern, but only if recent birth cohorts have a much higher (approximately 10-fold greater) risk and if incidence has increased with successive birth cohorts over the past 60-70 years. CONCLUSIONS: The pattern of lifetime prevalence observed in cross-sectional epidemiologic studies seems most plausibly explained by incidence that declines with age and where some respondents fail to recall past episodes. A cohort effect is not a necessary interpretation of the observed pattern of age-specific lifetime prevalence
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