198 research outputs found

    Profiling executive dysfunction in adults with autism and comorbid learning disability

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    Executive dysfunction is thought to be primary to autism. We examined differences in executive function between 20 adults with autism and learning disability and 23 individuals with learning disabilities outside the autistic spectrum. All participants were matched for chronological age and full-scale IQ, and were given a battery of tasks assessing fluency, planning, set-shifting, inhibition and working memory. Analyses of the individual tasks revealed very few significant differences between the two groups. However, analyses of composite scores derived for each executive domain revealed that the group with autism showed impaired performance on the working memory and planning tests. Together, these two measures were sufficient to classify participants into their diagnostic groups significantly better than would be expected by chance (75% of the autism group; 65% of the control group). Executive impairments were neither universal nor exclusive to the autism group, and we suggest that an alternative cognitive theory may better explain the cognitive profile we found

    Value and size investment strategies: evidence from the cross-section of returns in the South African equity market

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    Value and size related equity investment strategies are supported by a large body of empirical research that shows a persistent premium, both longitudinally and crosssectionally. However, the competing rational and behavioural finance explanations for the success of these strategies are a subject of debate. The rational explanation is that the premium earned on value shares or shares of small companies can be attributed to higher risk. Behaviouralists argue that such shares are not riskier and attribute the premium to cognitive errors and biases in human decision making. The purpose of this study is to determine, firstly, whether the value and size premium exist in South Africa during the period July 2006 to June 2012, which includes one of the worst equity market crises in history. Secondly, this study sets out to determine whether the premium earned on value and size strategies are adequately explained by the principles of rational finance theory. To provide evidence regarding the existence of the value premium and size effect, returns are analysed, cross-sectionally, on portfolios of shares sorted by value and size. For evidence of a rational explanation, returns are regressed on value and size variables, and the relative riskiness of value and small companies is analysed. The results show evidence of a value premium in portfolios of small companies, but not big companies. The size effect is found not to be statistically significant. While regressions do show significant relationships between value and size variables and returns, these variables are found not to be associated with higher levels of risk. The conclusion is that the evidence does not support a rational, risk based explanation of the return

    The FathomNet2023 Competition Dataset

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    Ocean scientists have been collecting visual data to study marine organisms for decades. These images and videos are extremely valuable both for basic science and environmental monitoring tasks. There are tools for automatically processing these data, but none that are capable of handling the extreme variability in sample populations, image quality, and habitat characteristics that are common in visual sampling of the ocean. Such distribution shifts can occur over very short physical distances and in narrow time windows. Creating models that are able to recognize when an image or video sequence contains a new organism, an unusual collection of animals, or is otherwise out-of-sample is critical to fully leverage visual data in the ocean. The FathomNet2023 competition dataset presents a realistic scenario where the set of animals in the target data differs from the training data. The challenge is both to identify the organisms in a target image and assess whether it is out-of-sample.Comment: Competition was presented as part of the 10th Fine Grained Visual Categorization workshop at the 2023 Computer Vision and Pattern Recognition conference. 4 pages, 4 figure

    Phase relationships between velocity, wall pressure, and wall shear stress in a forced turbulent boundary layer

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    A large scale spatio-temporally periodic disturbance was excited in a turbulent boundary layer via a wall-actuated dynamic roughness. Streamwise velocity, wall pressure, and direct wall shear stress measurements were made with a hot wire, pressure microphone, and a micro-scale differential capacitive sensor, respectively. Phase-averaged fields for the three quantities were calculated and analyzed. A phase calibration between the various sensors was performed with an acoustic plane wave tube over a range of operating conditions to validate a direct phase comparison between the respective quantities. Results suggest encouraging agreement between the phase of the wall shear stress and velocity near the wall; however, more refined velocity measurements are needed to make quantitative comparisons to the wall pressure. Overall, this work highlights the potential for wall-based control with applications towards reducing turbulent drag

    Frequency domain measurements of melt pool recoil force using modal analysis

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    Recoil pressure is a critical factor affecting the melt pool dynamics during Laser Powder Bed Fusion (LPBF) processes. Recoil pressure depresses the melt pool. When the recoil pressure is low, thermal conduction and capillary forces may be inadequate to provide proper fusion between layers. However, excessive recoil pressure can produce a keyhole inside the melt pool, which is associated with gas porosity. Direct recoil pressure measurements are challenging because it is localized over an area proportionate to the laser spot size producing a force in the mN range. This paper reports a vibration-based approach to quantify the recoil force exerted on a part in a commercial LPBF machine. The measured recoil force is consistent with estimates from high speed synchrotron imaging of entrained particles, and the results show that the recoil force scales with applied laser power and is inversely related to the laser scan speed. These results facilitate further studies of melt pool dynamics and have the potential to aid process development for new materials

    Chylous effusion presenting in a 37-year-old woman with severe hypothyroidism: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>We report what is to the best of our knowledge the second adult case of chylothorax clearly associated with severe hypothyroidism in the English-language medical literature. To the best of our knowledge, this is the first case of its kind reported without a prior history of malignancy.</p> <p>Case presentation</p> <p>A 37-year-old Hispanic woman with no reported significant past medical history initially presented with shortness of breath and inability to lose weight. She was found to have a large chylous effusion requiring chest-tube drainage, as well as severe hypothyroidism. After several weeks of thyroid hormone-replacement therapy, the formation of chylous pleural fluid in the patient greatly diminished, and the chest tube was removed. Upon long-term follow-up her minimal residual effusion remains stable on serial chest radiographs.</p> <p>Conclusion</p> <p>Although the exact pathophysiologic relation between low thyroid hormone levels and chyle formation remains to be elucidated, hypothyroidism should be a diagnostic consideration in patients with chylous effusions, especially those refractory to conventional treatments.</p

    Sensitivity of fluvial sediment source apportionment to mixing model assumptions: A Bayesian model comparison

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    Mixing models have become increasingly common tools for apportioning fluvial sediment load to various sediment sources across catchments using a wide variety of Bayesian and frequentist modeling approaches. In this study, we demonstrate how different model setups can impact upon resulting source apportionment estimates in a Bayesian framework via a one-factor-at-a-time (OFAT) sensitivity analysis. We formulate 13 versions of a mixing model, each with different error assumptions and model structural choices, and apply them to sediment geochemistry data from the River Blackwater, Norfolk, UK, to apportion suspended particulate matter (SPM) contributions from three sources (arable topsoils, road verges, and subsurface material) under base flow conditions between August 2012 and August 2013. Whilst all 13 models estimate subsurface sources to be the largest contributor of SPM (median ∟76%), comparison of apportionment estimates reveal varying degrees of sensitivity to changing priors, inclusion of covariance terms, incorporation of time-variant distributions, and methods of proportion characterization. We also demonstrate differences in apportionment results between a full and an empirical Bayesian setup, and between a Bayesian and a frequentist optimization approach. This OFAT sensitivity analysis reveals that mixing model structural choices and error assumptions can significantly impact upon sediment source apportionment results, with estimated median contributions in this study varying by up to 21% between model versions. Users of mixing models are therefore strongly advised to carefully consider and justify their choice of model structure prior to conducting sediment source apportionment investigations

    Functional outcomes and quality of life following complex tibial fractures treated with circular external fixation : a comparison between proximal, midshaft, and distal tibial fractures

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    AIM AND OBJECTIVE: The purpose of this study was to compare clinical results following complex proximal, midshaft, and distal tibial fractures and investigate whether there are differences in outcomes between these locations. MATERIALS AND METHODS: Patients between 18 years and 65 years of age and minimum follow-up of 12 months with complex tibial fractures treated with a circular ring fixator were included. Functional outcomes were assessed using the Association for the Study and Application of Methods of Ilizarov (ASAMI) functional and bone scores, Foot Function Index (FFI), Four Step Square Test (FSST), and Timed Up and Go Test (TUG). Quality of life was assessed by the EQ-5D score. RESULTS: A total of 45 patients were included: proximal fractures, n= 11; midshaft fractures, n= 17; and distal fractures, n= 17. ASAMI functional (p= 0.8) and bone scores (p= 0.3) were not different. Excellent and good bone scores were achieved in >90% in all groups. FFI was 30.9 + 24.7 in the proximal group, 33.9 + 27.7 in the midshaft group, and 28.8 + 26.9 in the distal group (p = 0.8). TUG was 9.0 + 2.7 sec in the proximal group, 9.0+3.5 in the midshaft group, and 8.5+2.0 in the distal group (p = 0.67). FSST was 10.7 + 2.5 sec in the proximal, 10.3 + 3.8 in the midshaft, and 8.9 + 1.8 in the distal fracture groups (p = 0.5). EQ-5D index value was highest in the distal (0.72), lowest in the proximal (0.55), and 0.70 in the midshaft fracture groups (p = 0.001). EQ-5D VAS was significantly different between the proximal (65) and midshaft (82.3) (p = 0.001) and between the distal (75) and proximal (65) fracture groups (p = 0.001). CONCLUSIONS: The results of this study suggest that the functional outcomes between proximal, midshaft, and distal complex tibial fractures are comparable. Their ability to ambulate afterward is comparable to age-related normative data, but complex tasks are more difficult and better compared to the ambulating ability of a healthy population aged 65 to 80 years. Patients with proximal tibial fractures had significantly more disability by at least one functional level and/or one health dimension.https://www.stlrjournal.com/journalDetails/STLRdm2022Orthopaedic Surger
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