334 research outputs found
A one-equation turbulence transport model for high Reynolds number wall-bounded flows
A one-equation turbulence model that avoids the need for an algebraic length scale is derived from a simplified form of the standard k-epsilon model equations. After calibration based on well established properties of the flow over a flat plate, predictions of several other flows are compared with experiment. The preliminary results presented indicate that the model has predictive and numerical properties of sufficient interest to merit further investigation and refinement. The one-equation model is also analyzed numerically and robust solution methods are presented
The Lopsidedness of Present-Day Galaxies: Results from the Sloan Digital Sky Survey
Large-scale asymmetries in the stellar mass distribution in galaxies are
believed to trace non-equilibrium situations in the luminous and/or dark matter
component. These may arise in the aftermath of events like mergers, accretion,
and tidal interactions. These events are key in the evolution of galaxies. In
this paper we quantify the large-scale lopsidedness of light distributions in
25155 galaxies at z < 0.06 from the Sloan Digital Sky Survey Data Release 4
using the m = 1 azimuthal Fourier mode. We show that the lopsided distribution
of light is primarily due to a corresponding lopsidedness in the stellar mass
distribution. Observational effects, such as seeing, Poisson noise, and
inclination, introduce only small errors in lopsidedness for the majority of
this sample. We find that lopsidedness correlates strongly with other basic
galaxy structural parameters: galaxies with low concentration, stellar mass,
and stellar surface mass density tend to be lopsided, while galaxies with high
concentration, mass, and density are not. We find that the strongest and most
fundamental relationship between lopsidedness and the other structural
parameters is with the surface mass density. We also find, in agreement with
previous studies, that lopsidedness tends to increase with radius. Both these
results may be understood as a consequence of several factors. The outer
regions of galaxies and low-density galaxies are more susceptible to tidal
perturbations, and they also have longer dynamical times (so lopsidedness will
last longer). They are also more likely to be affected by any underlying
asymmetries in the dark matter halo.Comment: 42 pages, 13 figures, 3 tables, accepted to Ap
Validation of the English Language Pain Sensitivity Questionnaire
Background and Objectives: The Pain Sensitivity Questionnaire (PSQ) is predictive of pain-related responses to experimental stimuli in German-speaking individuals. Here, we explored the validation of the English translation of the PSQ (PSQ-E). Methods: One hundred thirty-six patients scheduled to undergo a low back interventional procedure completed the PSQ-E and other questionnaires including the Brief Pain Inventory. Pain ratings on a visual analog scale (VAS) were obtained following 2 standardized injections of subcutaneous lidocaine (VAS 1, infiltration in hand; VAS 2, infiltration of procedural site). The VAS measures were compared with the PSQ-E data and other inventories using linear regression analysis with stepwise selection of variables. Results: The PSQ-E properties were in all respects similar to those of the original German PSQ. VAS 1 magnitude was predicted by PSQ-E-minor (r = 0.26, P < 0.01). VAS 2 magnitude was predicted by PSQ-E-minor (r = 0.34, P < 0.001), and the prediction was significantly enhanced by further inclusion of the Brief Pain Inventory interference score (total r = 0.40, P < 0.001). Conclusions: The study demonstrated that a significant correlation exists between the PSQ-E and clinically relevant pain ratings. This study validates the PSQ-E both in terms of measuring pain sensitivity and as possible means of recognizing patients with high pain sensitivity. Defining this subset of patients may have clinical utility in the future
Polydopamine-lysophosphatidate-functionalised titanium: A novel hybrid surface finish for bone regenerative applications
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Aseptic loosening of total joint replacements (TJRs) continues to be the main cause of implant failures. The socioeconomic impact of surgical revisions is hugely significant; in the United Kingdom alone, it is estimated that ÂŁ135m is spent annually on revision arthroplasties. Enhancing the longevity of titanium implants will help reduce the incidence and overall cost of failed devices. In realising the development of a superior titanium (Ti) technology, we took inspiration from the growing interest in reactive polydopamine thin films for biomaterial surface functionalisations. Adopting a âone-potâ approach, we exposed medical-grade titanium to a mildly alkaline solution of dopamine hydrochloride (DHC) supplemented with (3S)1-fluoro-3-hydroxy-4-(oleoyloxy)butyl-1-phosphonate (FHBP), a phosphatase-resistant analogue of lysophosphatidic acid (LPA). Importantly, LPA and selected LPA analogues like FHBP synergistically cooperate with calcitriol to promote human osteoblast formation and maturation. Herein, we provide evidence that simply immersing Ti in aqueous solutions of DHC-FHBP afforded a surface that was superior to FHBP-Ti at enhancing osteoblast maturation. The facile step we have taken to modify Ti and the biological performance of the final surface finish are appealing properties that may attract the attention of implant manufacturers in the future
Enhancing experiential learning in planning education through an online toolkit of resources
This paper reports on the development of an online toolkit of resources to support the use and assessment of experiential learning (EL) across planning programs. Planning graduates face diverse workplace demands with expectations to address the local and regional implications of global trends, integrate technological advances with existing planning processes, as well as interpret and integrate changing legislative and institutional arrangements. Planning education is about educators, practitioners and students coming together. Equipping students for increasing complexity and change requires planning educators to design programs that facilitate the learning of personal and professional skills and both broad and specialised planning knowledge. Planning practitioners, in partnership with educators, make further valuable contributions by providing a range of âreal worldâ learning experiences where students can directly develop new skills, knowledge and qualities. Experiential learning allows students to develop confidence within a safe environment through a series of activities and reflection that link theory to practice. However, developing EL learning outcomes, teaching activities and assessment can be demanding and time consuming for planning educators. In response, the Experiential Learning in Planning Education: Resources and Tools for Good Practice research project developed an online toolkit of case studies and associated resources to assist planning educators and practitioners in their application of EL. These case studies, developed by the partners in the project, explain the rationale of using particular EL activities based on a set of EL principles; how these activities are assessed; and reflections on how they could be improved for future use. The case studies also include numerous âhow toâ resources, such as checklists and handy hints for organising activities, evaluation tools and examples of studentsâ work. Furthermore, the toolkit website is an interactive and âlivingâ repository where additional case studies by other EL users can be included to enhance the diversity and richness of the resources available. The toolkit is expected to particularly benefit new planning educators but should also be of interest to planning schools and practitioners around the globe who are endeavouring to facilitate studentsâ education in a rapidly changing world
The fishes of ascension Island, central Atlantic Ocean - new records and an annotated checklist
A checklist of the fishes of Ascension Island is presented. The species Rhincodon typus, Alopias superciliosus, Isurus oxyrinchus, Carcharhinus obscurus, Galeocerdo cuvier, Sphyrna lewini, Hexanchus griseus, Manta birostris, Gymnothorax vicinus, Hippocampus sp., Epinephelus itajara, Cookeolus japonicus, Apogon pseudomaculatus, Phaeoptyx pigmentaria, Remora albescens, Caranx bartholomaei, Carangoides ruber, Decapterus tabl, Seriola dumerili, Thalassoma sanctaehelenae, Cryptotomus sp., Ruvettus pretiosus, Acanthocybium solandri, Auxis rochei, Auxis thazard, Euthynnus alletteratus, Katsuwonus pelamis, Thunnus alalunga, Thunnus obesus, Xiphias gladius, Istiophorus platypterus, Kajikia albida, Makaira nigricans, Tetrapturus pfluegeri, Hyperoglyphe perciformis, Schedophilus sp., Cantherhines macrocerus, Sphoeroides pachygaster and Diodon eydouxii are recorded for the first time from Ascension Island. We have recognized two previous records as identification errors and indicate 11 other records as doubtful. Including the 40 new records, we now list 173 fish species from Ascension Island, of which 133 might be considered 'coastal fish species'. Eleven of these (8.3%) appear to be endemic to the island and a further 16 species (12%) appear to be shared endemics with St Helena Island.Darwin Initiative [EIDCF012]info:eu-repo/semantics/publishedVersio
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Population vs Individual Prediction of Poor Health from Results of Adverse Childhood Experiences Screening
Importance: Adverse childhood experiences (ACEs) are well-established risk factors for health problems in a population. However, it is not known whether screening for ACEs can accurately identify individuals who develop later health problems. Objective: To test the predictive accuracy of ACE screening for later health problems. Design, Setting, and Participants: This study comprised 2 birth cohorts: the Environmental Risk (E-Risk) Longitudinal Twin Study observed 2232 participants born during the period from 1994 to 1995 until they were aged 18 years (2012-2014); the Dunedin Multidisciplinary Health and Development Study observed 1037 participants born during the period from 1972 to 1973 until they were aged 45 years (2017-2019). Statistical analysis was performed from May 28, 2018, to July 29, 2020. Exposures: ACEs were measured prospectively in childhood through repeated interviews and observations in both cohorts. ACEs were also measured retrospectively in the Dunedin cohort through interviews at 38 years. Main Outcomes and Measures: Health outcomes were assessed at 18 years in E-Risk and at 45 years in the Dunedin cohort. Mental health problems were assessed through clinical interviews using the Diagnostic Interview Schedule. Physical health problems were assessed through interviews, anthropometric measurements, and blood collection. Results: Of 2232 E-Risk participants, 2009 (1051 girls [52%]) were included in the analysis. Of 1037 Dunedin cohort participants, 918 (460 boys [50%]) were included in the analysis. In E-Risk, children with higher ACE scores had greater risk of later health problems (any mental health problem: relative risk, 1.14 [95% CI, 1.10-1.18] per each additional ACE; any physical health problem: relative risk, 1.09 [95% CI, 1.07-1.12] per each additional ACE). ACE scores were associated with health problems independent of other information typically available to clinicians (ie, sex, socioeconomic disadvantage, and history of health problems). However, ACE scores had poor accuracy in predicting an individual's risk of later health problems (any mental health problem: area under the receiver operating characteristic curve, 0.58 [95% CI, 0.56-0.61]; any physical health problem: area under the receiver operating characteristic curve, 0.60 [95% CI, 0.58-0.63]; chance prediction: area under the receiver operating characteristic curve, 0.50). Findings were consistent in the Dunedin cohort using both prospective and retrospective ACE measures. Conclusions and Relevance: This study suggests that, although ACE scores can forecast mean group differences in health, they have poor accuracy in predicting an individual's risk of later health problems. Therefore, targeting interventions based on ACE screening is likely to be ineffective in preventing poor health outcomes
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