1,625 research outputs found
Normative Models and Their Success
In this paper, we explore an under-investigated question concerning the class of formal models that aim at providing normative guidance. We call such models normative models. In particular, we examine the question of how normative models can successfully exert normative guidance. First, we highlight the absence of a discussion of this questionâwhich is surprising given the extensive debate about the success conditions of descriptive modelsâand motivate its importance. Second, we introduce and discuss two potential accounts of the success conditions of normative models. Our tentative conclusion is that the second account is more promising.Peer Reviewe
Do Normal Radiographs Exclude Asphericity of the Femoral Head-Neck Junction?
Asphericity of the femoral head-neck junction is one cause for femoroacetabular impingement of the hip. However, the asphericity often is underestimated on conventional radiographs. This study compares the presence of asphericity on conventional radiographs with its appearance on radial slices of magnetic resonance arthrography (MRA). We retrospectively reviewed 58 selected hips in 148 patients who underwent a surgical dislocation of the hip. To assess the circumference of the proximal femur, alpha angle and height of asphericity were measured in 14 positions using radial slices of MRA. The hips were assigned to one of four groups depending on the appearance of the head-neck junction on anteroposterior pelvic and lateral crosstable radiographs. Group I (n=19) was circular on both planes, Group II (n=19) was aspheric on the crosstable view, Group III (n=4) was aspheric on the anteroposterior view, and Group IV (n=13) was aspheric on both views. In all four groups, the highest alpha angle was found in the anterosuperior area of the head-neck junction. Even when conventional radiographs appeared normal, an increased alpha angle was present anterosuperiorly. Without the use of radial slices in MRA, the asphericity would be underestimated in these patients. Level of Evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidenc
Normative Models and Their Success
In this paper, we explore an under-investigated question concerning the class of formal models that aim at providing normative guidance. We call such models normative models. In particular, we examine the question of how normative models can successfully exert normative guidance. First, we highlight the absence of a discussion of this questionâwhich is surprising given the extensive debate about the success conditions of descriptive modelsâand motivate its importance. Second, we introduce and discuss two potential accounts of the success conditions of normative models. Our tentative conclusion is that the second account is more promising.</jats:p
Vascular Diseases of the Spinal Cord: A Review
Opinion statement: ⢠In acute spinal cord ischemia syndrome (ASCIS), treatment recommendations are derived from data of cerebral ischemic stroke, atherosclerotic vascular disease and acute spinal cord injury. Besides acute management, secondary prevention is of major importance. Pathologies affecting the aorta as well as underlying cerebrovascular conditions should be treated whenever possible. ⢠ASCIS may occur after aortic surgery, less often after thoracic endovascular aortic repair (TEVAR). Protocols are proposed. ⢠Acute spinal cord hemorrhage can be treated surgically and/or pharmacologically. ⢠Symptomatic treatment in patients with a spinal cord lesion is of major importance. Depending on level and extension of the lesion, there is a risk for systemic and neurological complications, which may be life-threatening. ⢠Each spinal vascular malformation is a unique lesion that needs an individualized treatment algorithm. In case of a symptomatic vascular malformation, endovascular intervention is the primary treatment option. ⢠Spinal dural Arteriovenous fistula (AVF) may be treated endovascularly or surgically. If preoperative localization of the fistula is possible, surgery is feasible with a low complication rate. In comparison, endovascular approaches are less invasive. ⢠Spinal AVM are rather treated endovascularly than surgically or in a stepwise multidisciplinary approach. ⢠Symptomatic and exophytic spinal cavernous angiomas should be treated surgically. Deep spinal cavernous angiomas that are asymptomatic or only show mild symptoms can be observe
Towards Exascale CFD Simulations Using the Discontinuous Galerkin Solver FLEXI
Modern high-order discretizations bear considerable potential for the
exascale era due to their high fidelity and the high, local computational load
that allows for computational efficiency in massively parallel simulations. To
this end, the discontinuous Galerkin (DG) framework FLEXI was selected to
demonstrate exascale readiness within the Center of Excellence for Exascale CFD
(CEEC) by simulating shock buffet on a three-dimensional wing segment at
transsonic flight conditions. This paper summarizes the recent progress made to
enable the simulation of this challenging exascale problem. For this, it is
first demonstrated that FLEXI scales excellently to over 500 000 CPU cores on
HAWK at the HLRS. To tackle the considerable resolution requirements near the
wall, a novel wall model is proposed that takes compressibility effects into
account and yields decent results for the simulation of a NACA 64A-110 airfoil.
To address the shocks in the domain, a finite-volume-based shock capturing
method was implemented in FLEXI, which is validated here using the simulation
of a linear compressor cascade at supersonic flow conditions, where the method
is demonstrated to yield efficient, robust and accurate results. Lastly, we
present the TensorFlow-Fortran-Binding (TFFB) as an easy-to-use library to
deploy trained machine learning models in Fortran solvers such as FLEXI.Comment: 15 pages, 5 figure
A small series of pole sport injuries
Pole sport is a relatively new athletic sport that is gaining increasing popularity and for which national and international championships are held. It evolved from pole dance and harbours the risk of falls from heights of up to three metres. Currently, no studies on pole sport injuries are available. This is the first description of a small series of five pole sport injuries. A retrospective review of the case histories and radiological findings was performed, and in addition, a follow-up interview was carried out. All the patients were female and had a mean age of 27.2 years. Most injuries were located in the head, neck or spine. The use of proper training equipment like landing mats and grip aids could probably reduce accidents
A higher-level MRP supertree of placental mammals
BACKGROUND: The higher-level phylogeny of placental mammals has long been a phylogenetic Gordian knot, with disagreement about both the precise contents of, and relationships between, the extant orders. A recent MRP supertree that favoured 'outdated' hypotheses (notably, monophyly of both Artiodactyla and Lipotyphla) has been heavily criticised for including low-quality and redundant data. We apply a stringent data selection protocol designed to minimise these problems to a much-expanded data set of morphological, molecular and combined source trees, to produce a supertree that includes every family of extant placental mammals. RESULTS: The supertree is well-resolved and supports both polyphyly of Lipotyphla and paraphyly of Artiodactyla with respect to Cetacea. The existence of four 'superorders' â Afrotheria, Xenarthra, Laurasiatheria and Euarchontoglires â is also supported. The topology is highly congruent with recent (molecular) phylogenetic analyses of placental mammals, but is considerably more comprehensive, being the first phylogeny to include all 113 extant families without making a priori assumptions of suprafamilial monophyly. Subsidiary analyses reveal that the data selection protocol played a key role in the major changes relative to a previously published higher-level supertree of placentals. CONCLUSION: The supertree should provide a useful framework for hypothesis testing in phylogenetic comparative biology, and supports the idea that biogeography has played a crucial role in the evolution of placental mammals. Our results demonstrate the importance of minimising poor and redundant data when constructing supertrees
Petrology, geochemistry, and cosmic-ray exposure age of lherzolitic shergottite Northwest Africa 1950
Northwest Africa (NWA) 1950 is a new member of the lherzolitic shergottite clan of the Martian meteorites recently found in the Atlas Mountains. The petrological, mineralogical, and geochemical data are very close to those of the other known lherzolitic shergottites. The meteorite has a cumulate gabbroic texture and its mineralogy consists of olivine (Fo66 to Fo75), low and high-Ca pyroxenes (En78Fs19Wo2- En60Fs26W14; En53Fs16Wo31-En45Fs14Wo41), and plagioclase (An57Ab41Or1 to An40Ab57Or3; entirely converted into maskelynite during intense shock metamorphism). Accessory minerals include phosphates (merrillite), chromite and spinels, sulfides, and a glass rich in potassium. The oxygen isotopic values lie on the fractional line defined by the other SNC meteorites (Î17O = 0.312 â°). The composition of NWA 1950 is very similar to the other lherzolitic shergottites and suggests an origin from the same magmatic system, or at least crystallization from a close parental melt. Cosmogenic ages indicate an ejection age similar to those of the other lherzolitic shergottites. The intensity of the shock is similar to that observed in other shergottites, as shown by the occurrence of small melt pockets containing glass interwoven with stishovite
Acceptance, Barriers, and Future Preferences of Mobile Health Among Patients Receiving Trauma and Orthopedic Surgical Care: Paper-Based Survey in a Prospective Multicenter Study
Background:
Smartphones have become an essential part of everyday life and it is undeniable that apps offer enormous opportunities for dealing with future challenges in public health. Nevertheless, the exact patient requirements for medical apps in the field of orthopedic and trauma surgery are currently unknown.
Objective:
The aim of this study was to define target groups, evaluate patient requirements, and the potential and pitfalls regarding medical apps specific for patients receiving orthopedic and trauma surgical care.
Methods:
A prospective multicenter study was conducted between August 2018 and December 2019 at a German trauma center and 3 trauma surgery/orthopedic practices. A paper-based survey consisting of 15 questions evaluated information regarding smartphone and medical app usage behavior. In addition, suggested app functions were rated using Likert scales. Descriptive statistics and binary log-binomial regression were performed.
Results:
A total of 1055 questionnaires were included in our statistical analysis. Approximately 89.57% (945/1055) of the patients in this study owned a smartphone. Smartphone ownership probability decreased with every decade of life and increased with higher levels of education. Medical information was obtained via mobile web access by 62.65% (661/1055) of the patients; this correlated with smartphone ownership in regard to age and educational level. Only 11.18% (118/1055) of the patients reported previous medical app usage, and 3.50% (37/1055) of the patients received an app recommendation from a physician. More than half (594/1055, 56.30%) of the patients were unwilling to pay for a medical app. The highest rated app functions were information about medication, behavioral guidelines, and medical record archival. An improved treatment experience was reported through the suggested app features by 71.18% (751/1055) of the patients.
Conclusions:
Mobile devices are a widely used source of information for medical content, but only a minority of the population reported previous medical app usage. The main target group for medical apps among patients receiving orthopedic and trauma surgical care tends to be the younger population, which results in a danger of excluding fringe groups, especially the older adults. Education seems to be one of the most important pull factors to use smartphones or a mobile web connection to obtain health information. Medical apps primarily focusing on an optimized patient education and flow of information seem to have the potential to support patients in health issues, at least in their subjective perception. For future target groupâoriented app developments, further evidence on the clinical application, feasibility, and acceptance of app usage are necessary in order to avoid patient endangerment and to limit socioeconomic costs
Long-term effectiveness and prediction of treatment outcome in cognitive behavioral therapy and sertraline for late-life anxiety disorders
Background: Although anxiety disorders are prevalent in older adults, randomized controlled trials of treatment effectiveness for late-life anxiety are scarce and have focused primarily on the effectiveness of psychotherapeutic interventions. However, recent findings suggest that in some cases, pharmacological treatment may be more beneficial for late-life anxiety disorders. As yet, there have been no systematic studies investigating prognostic factors for the outcome of cognitive behavioral therapy (CBT) and pharmacotherapy for late-life anxiety. The objective of the present study was to study long-term treatment outcomes and to explore differential predictors for both short-term and long-term treatment outcomes of sertraline and CBT for late-life anxiety disorders. Methods: Participants of a randomized controlled trial (RCT) comparing sertraline and CBT for the treatment of late-life anxiety were contacted one year after completing their treatment, so that predictors for both short-term and long-term treatment outcome could be established. Results: Sertraline showed a greater reduction of symptoms than CBT on anxiety (Hamilton Anxiety Rating Scale; HARS) and worry (Worry Domain Questionnaire) ratings at one-year follow-up. The strongest predictor for short-term CBT outcome was poor perceived health, explaining 40% of the variance in post-treatment residual gain scores on the HARS. The strongest predictor for long-term CBT outcome was neuroticism, explaining 20% of the variance in residual gain scores at one-year follow-up. Analyses revealed no significant predictors for treatment outcome in sertraline participants. Conclusions: Our study suggests that long-term use of sertraline might be more beneficial for late-life anxiety than a 15-week CBT program. Poor perceived health and neuroticism are predictive of less improvement after CBT in anxious older adults. Implications of these findings are discussed
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