296 research outputs found
Coastal drowning: A scoping review of burden, risk factors, and prevention strategies.
Get PDFObjectiveCoastal drowning is a global public health problem which requires evidence to support safety initiatives. The growing multidisciplinary body of coastal drowning research and associated prevention countermeasures is diverse and has not been characterised as a whole. The objective of this scoping review was to identify key concepts, findings, evidence and research gaps in the coastal drowning literature to guide future research and inform prevention activities.MethodsWe conducted a scoping review to identify peer reviewed studies published before May 2020 reporting either (i) fatal unintentional coastal drowning statistics from non-boating, -disaster or -occupational aetiologies; (ii) risk factors for unintentional fatal coastal drowning; or (iii) coastal drowning prevention strategies. Systematic searches were conducted in six databases, two authors independently screened studies for inclusion and one author extracted data using a standardised data charting form developed by the study team.ResultsOf the 146 included studies, the majority (76.7%) were from high income countries, 87 (59.6%) reported coastal drowning deaths, 61 (41.8%) reported risk factors, and 88 (60.3%) reported prevention strategies. Populations, data sources and coastal water site terminology in the studies varied widely; as did reported risk factors, which most frequently related to demographics such as gender and age. Prevention strategies were commonly based on survey data or expert opinion and primarily focused on education, lifeguards and signage. Few studies (n = 10) evaluated coastal drowning prevention strategies.DiscussionCoastal drowning is an expansive, multidisciplinary field that demands cross-sector collaborative research. Gaps to be addressed in coastal safety research include the lack of research from lower resourced settings, unclear and inconsistent terminology and reporting, and the lack of evaluation for prevention strategies. Advancing coastal drowning science will result in a stronger evidence base from which to design and implement effective countermeasures that ultimately save lives and keep people safe
Concerns about data integrity of 30 randomized clinical trials from one author.
No full textIntroduction
In 2021, we learnt about the problems in studies on ivermectin and hydrocholoroquine in COVID-19. We noticed an appreciable number of unfunded randomised clinical trials (RCTs) on the treatment of COVID-19 conducted across three centres in Egypt (Tanta University, Assiut University, Ain-shams University) on COVID-19 patients with similar inclusion criteria and overlapping time frames. Dr Sherief M Abd-Elsalam ran seven such RCTs across these three centres; four of these RCTs have since been retracted. We therefore set out to systematically analyse the integrity of all RCTs (co-)authored by Dr Abd-Elsalam, in particular 23 RCTs on Gastroenterology and Hepatology.
Methods
We searched PubMed, Google Scholar, Scopus and clinical trial registries for RCTs published by Dr Sherief M Abd-Elsalam, affiliated with the Department of Tropical Medicine and Infectious Diseases, Faculty of Medicine, Tanta University, Tanta, Egypt. We assessed trial registration, tables for identical data values, statistical errors, and improbable data trends. We assessed the probability of true randomization by assessing baseline characteristics through a Monte Carlo Analysis.
Results
We report on 30 published randomized control trials (RCTs) of Dr. Sherief Abd-Elsalam, in particular 23 RCTs on Gastroenterology and Hepatology. We found important issues in all RCTs examined. Of these 23 RCTs, 10 RCTs had substantial trial registration inconsistencies. Only one of these 10 RCTs has been retracted to date. We found nine RCTs with substantial statistical mistakes, five RCTs with similarities between tables unlikely to happen by chance, four RCTs with implausible Gaussian distributions, three RCTs in which almost all dichotomous variables had even values, while part of at least one study was plagiarized. Monte Carlo analysis indicated that the probability that distribution of baseline characteristics due to randomisation was 0.0000228. According to the trial registration, Dr. Abd-Elsalam is coordinating 76 clinical trials with 45 trials currently marked as ‘Recruiting’ and 17 trials marked as ‘Unknown Status’ as of November 2022.
Interpretation
We strongly recommend a thorough investigation of the data integrity of all RCTs by Dr Sherief M Abd-Elsalam by journal editors. Until the completion of such an investigation, we suggest that none of these studies are used to inform clinical practice
Maximizing Revenue Selling Retro Sneakers on eBay: A Data-Driven Approach
Get PDFIn recent years, athletic shoe brands have increased production and sales of retro sneakers. Retro sneakers consist of popular styles from the 80s and 90s that are highly valued today, in 2013 (Void, 2013). With a dedicated customer market eager to purchase newly released retro sneakers, retailers often sell out of styles in minutes thus quickly creating a secondary market. This study gathers and analyzes completed sales data from the biggest secondary sneaker market, eBay. The findings of this study help to explain why the retro sneaker market is so popular and suggests that selling large shoe sizes, at a fixed price, close to a sneaker's release date will maximize seller revenue. The article's author has been an avid sneaker connoisseur for many years, and during this time, has completed hundreds of eBay transactions. To complete the study, the author leverages a combination of observed market behaviors and critical thinking.Master of Science in Information Scienc
Placental Massive Perivillous Fibrin Deposition associated with Coxsackievirus A16-report of a case, and review of the literature
No full textMassive placental perivillous fibrinoid deposition in the placenta is thought to be an immune-related condition associated with poor perinatal outcomes, including growth restriction and intrauterine fetal demise, with a high risk of recurrence. Rare cases have been associated with Coxsackievirus infection. We present such a case and review the literature.The final publication is available at Springer via https://dx.doi.org/10.2350/15-10-1726-CR.1Peer reviewe
Understanding and Addressing Arab-American Mental Health Disparities
Get PDFThe landscape of mental healthcare and focus on disparities research in the United States has vastly improved in recent years. However, Arab-Americans continue to be a commonly overlooked group within the scope of the research. This trend is especially worrisome given detrimental factors for Arab-Americans that have arisen as a factor of 9/11 and in the scope of the 2016 United States Presidential Election. This work explores barriers to accessing formal mental health care and offers recommendations to reconcile them for Arab-Americans. The present study completes this through a review of the literature and an interview conducted by the author of a panel of mental health professionals at a community health organization in order to gain a contemporary perspective of the issue. Salient suggestions that arise from this study are reducing stigma in the community by incorporating increased usage of primary care and religious providers as well as family therapies; the allocation of Arabic-speaking translators to clinics or a focus on hiring Arabic-speaking practitioners; supporting safety-net insurance funding; increased education on what psychotherapy and mental illness are; and pushing the necessity of professional training in the culture, religion, and preferences of Arab-Americans
Addressing the Policy-bias of Q-learning by Repeating Updates
No full textQ-learning is a very popular reinforcement learning algorithm being proven to converge to optimal policies in Markov decision processes. However, Q-learning shows artifacts in non-stationary environments, e.g., the probability of playing the optimal action may decrease if Q-values deviate significantly from the true values, a situation that may arise in the initial phase as well as after changes in the environment.These artifacts were resolved in literature by the variant Frequency Adjusted Q-learning (FAQL). However, FAQL also suffered from practical concerns that limited the policy subspace for which the behavior was improved. Here, we introduce the Repeated Update Q-learning (RUQL), a variant of Q-learning that resolves the undesirable artifacts of Q-learning without the practical concerns of FAQL.We show (both theoretically and experimentally) the similarities and differences between RUQL and FAQL (the closest state-of-the-art). Experimental results verify the theoretical insights and show how RUQL outperforms FAQL and QL in non-stationary environments
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Ramified lifts of Galois representations and dimension of ordinary deformation rings
Get PDFLet be a totally real number field, a finite field of characteristic and \ol{\rho}: \tr{Gal}(\ol F/F) \ra GL_n(k) a continuous Galois representation. Under some technical hypotheses on \ol{\rho} we extend the method of Khare and Ramakrishna of constructing ramified characteristic zero lifts of \rh from the setting of to . As an application of this method we prove the existence of closed points x \in \tr{Spec}(R^{\tr{ord}}[1/p]), on a certain nearly ordinary deformation ring R^{\tr{ord}}, such that Mazur's dimension conjecture is true locally at . In the process we obtain examples of ordinary Galois representations \rho: G_{F, S\cup Q} \ra GL_n(\mc O), where \mc O is a finite extension of , such that its adjoint Selmer group H^1_{\mc L} (G_{F, S\cup Q}, ad^0\, \rho \otimes \Q_p/\Z_p) is finite. We then determine the exact size of these Selmer groups in terms of the ramification index of the primes in the auxiliary set
Slip at the surface of an oscillating spheroidal particle in a micropolar fluid
Get PDFThe axisymmetric rectilinear and rotary oscillations of a spheroidal particle in an incompressible micropolar fluid are considered. Basset type linear slip boundary conditions on the surface of the solid spheroidal particle are used for velocity and microrotation. Under the assumption of small amplitude oscillations, analytical expressions for the fluid velocity field and microrotation components are obtained in terms of a first order small parameter characterizing the deformation. For the rectilinear oscillations, the drag acting on the particle is evaluated and expressed in terms of two real parameters for the prolate and oblate spheroids. Also, the couple exerted on the spheroid is evaluated for the prolate and oblate spheroids for the rotary oscillations. Their variations with respect to the frequency, deformity, micropolarity and slip parameters are tabulated and displayed graphically. Well-known results are deduced and comparisons are made between the classical viscous fluids and micropolar fluids. The results of this study serve to improve the accuracy of viscosity measurements for micropolar fluids.
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Ramkissoon, Slip flow past an approximate spheroid, Acta Mech. 123 (1997) 227--233. S. Senchenko, H. J. Keh, Slipping Stokes flow around a slightly deformed sphere, Phys. Fluids 18 (2006) 088104. doi:10.1063/1.2337666 Y. C. Chang, H. J. Keh, Translation and rotation of slightly deformed colloidal spheres experiencing slip, J. Colloid Interface Sci. 330 (2009) 201--210. doi:10.1016/j.jcis.2008.10.055 H. Lamb, Hydrodynamics, 6th ed. Cambridge. 1932. G. B. Jeffery, Steady rotation of a solid of revolution in a viscous fluid, Pro. Lond. Math. Soc. 14 (1915) 327--338. R. P. Kanwal, Steady rotation of axially symmetric bodies in a viscous fluid, J. Fluid Mech. 10 (1960) 17--24. P. Tekasakul, R. V. Tompson, S. K. Loyalka, Rotatory oscillations of arbitrary axisymmetric bodies in an axisymmetric viscous flow: Numerical solutions, Phys. Fluids 10 (1998) 2797--2818. doi:10.1063/1.869803 P. Tekasakul, S. K. Loyalka, Rotary oscillations of axisymmetric bodies in an axisymmetric viscous flow with slip: Numerical solutions for sphere and spheroids, Int. J. Numer. Meth. Fluids 41 (2003) 823--840. J. Happel, H. Brenner, Low Reynolds number hydrodynamics, Martinus Nijoff, The Hague, Netherlands (1983). S. K. Lakshmana, Rao, N. C. Pattabhi Ramacharyulu, P. Bhujanga Rao, Slow steady rotation of a sphere in a micropolar fluid, Int. J. Eng. Sci. 7 (1969) 905--916. doi:10.1016/0020-7225(69)90083-4 S. K. Lakshmana Rao, P. Bhujanga Rao, The oscillations of a sphere in a micropolar fluid, Int. J. Eng. Sci. 9 (1971) 651--672. doi:10.1016/0020-7225(71)90068-1 S. K. Lakshmana Rao, T. K. V. Iyengar, The rectilinear oscillations of a spheroid in a micropolar fluid, Int. J. Eng. Sci. 19 (1981) 161--188. doi:10.1016/0020-7225(81)90020-3 K. S. Sran, Longitudinal oscillations of a sphere in a micropolar fluid, Acta Mech. 85 (1990) 71--78. doi:10.1007/BF01213543 D. Srinivasa Charya, T. K. V. 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Neurosurgical treatment in cerebral ischemia: literature review
Get PDFUniversitatea de Stat de Medicină şi Farmacie „Nicolae Testemiţanu”, Chişinău, Republica MoldovaIntroducere. În ciuda cheltuielilor mari asociate cu ischemia cerebrală, există puține tratamente eficiente disponibile. Eșecul tuturor tratamentelor, cu excepția tromboliticelor și a hipotermiei, sugerează că este necesară urgent dezvoltarea unui nou tratament neurochirurgical. Obiectiv. Scopul acestei lucrări este de a analiza tratamentul neurochirurgical în ischemia cerebrală și rezultatele implicate în ultimii 10 ani și de a trece în revistă rapoartele istorice și recente din literatura de specialitate referitoare la tehnicile de revascularizare. Material și metode. Sinteza literaturii a fost realizată în ultimii 10 ani prin bazele de date Medscape, PubMed și altele. Au fost folosiți termenii „ischemie cerebrală”, „tratament neurochirurgical” și „revascularizare”. Accentul a fost pus pe publicațiile publicate în 2013 și după. Au fost luate, de asemenea, în considerare lucrările de recenzie din reviste credibile. Informațiile pentru acest articol au provenit din lectura a 60 de rezumate. Rezultate. Dezvoltarea tehnicilor neurochirurgicale pentru tratarea eficientă a ischemiei cerebrale, cum ar fi angiografia cerebrală, intervenția chirurgicală de bypass vascular, neurochirurgia endovasculară, angioplastia carotidiană, stentarea arterei carotide, embolectomia mecanică, a fost posibilă și de progresele tehnologice. Prezența leziunii ischemice cerebrale la indivizii asimptomatici crește riscul unui viitor incident neurologic de la 1% la 4% an, întărind nevoia de revascularizare carotidiană. Dacă leziunea este minoră (4.000 mm3), prezența leziunii ischemice cerebrale nu pare să afecteze rezultatul revascularizării carotidei la pacienții simptomatici. Trombectomie mecanică este utilizată pentru reperfuzia țesutului cerebral recuperabil și pentru prevenirea accidentului vascular cerebral. Concluzie. A existat o creștere a siguranței și eficacității opțiunilor de tratament ca urmare a dezvoltărilor tehnologice recente și a perfecționării metodelor neurochirurgicale în curs. Cu toate acestea, trebuie făcută mai multă muncă, deoarece mai multe studii randomizate controlate în curs și trecute caută cea mai bună metodă de tratare a ischemiei cerebrale.Background. Despite the high expenditures associated with cerebral ischemia, there are few effective treatments available. The failure of all treatments, with the exception of thrombolytics and hypothermia, suggest the development of novel neurosurgical treatment is urgently required. Objective. The goal of this paper is to analyze the neurosurgical treatment in cerebral ischemia and the outcomes involved in the past 10 years and review the historical and recent reports in the literature related to revascularization techniques. Materials and methods. Literature synthesis was conducted from past 10years through the databases Medscape, PubMed, and others. The terms „cerebral ischemia,” „neurosurgical treatment”, revascularization” were employed. The focus was on publications published in 2013 and after. Review papers from credible journals were also taken into account. The information for this article came from reading an altogether of 60 abstracts. Results. The development of neurosurgical techniques for effectively treating cerebral ischemia, such as cerebral angiography, vascular bypass surgery, endovascular neurosurgery, carotid angioplasty, carotid-artery stenting, mechanical embolectomy, was also made possible by technological advances. The presence of cerebral ischemic lesion in asymptomatic individuals raises the risk of a future neurologic incident from 1% to 4% year, strengthening the need for carotid revascularization. If the lesion is minor (4,000 mm 3 ), the presence of cerebral ischemic lesion does not appear to affect the result of carotid revascularization in symptomatic patients. Mechanical thrombectomy is used for reperfusion of salvageable brain tissue, and for the prevention of stroke. Conclusion. There has been increase in the safety and efficacy of treatment choices because of recent technological developments and ongoing neurosurgical method refinement. Nevertheless, more work has to be done as several ongoing and past randomized controlled trials look for the best method for treating in cerebral ischemia
Supporting the attentional momentum view of IOR: Is attention biased to go right? Perception
No full textThe environment is full of a multitude of stimuli, and at any particular moment in time, our attention can be directed only toward a very small segment of them. Thus, our attentional-orienting system needs to operate in as efficient a manner as possible to ensure our survival. For example, if an animal seeking prey fails to find something at one location, it will be disadvantageous for that animal to keep returning its attention to that location. It will be more eff icient to reorient attention to novel locations once searches of previous locations have failed to locate the object of interest. Thus, evolutionarily, a mechanism that favors looking at novel locations would be highly adaptive. For humans, however, the search for prey and the avoidance of predators are no longer of paramount importance. Nevertheless, humans still actively engage in search behaviors. It is common for a person to be looking for a specific item on a desk or for a particular friend at a party. In these situations, just as it is for animals in the wild, perseverance in looking at one location will result in inefficient search. Thus, it would not be surprising to observe evidence for a mechanism that favors orienting to novel locations in the human attentional system. The focus of the present paper is on the mechanism that underlies this bias for orienting toward novel locations in humans. The examination will be restricted to the adult population and, specifically, to a phenomenon termed inhibition of return (IOR). To this end, the phenomenon will first be described, and a brief overview of some of the evidence supporting the existence of inhibitory processes underlying attentional orienting will be provided. Following the description of the inhibitory account, an alternative account based on attentional momentum will be described. According to the attentional momentum account of IOR, once attention is set in motion, it tends to continue moving along that vector. Past evidence in favor of the attentional momentum notion will be briefly provided, and then several experiments, the motive of which was to further test the attentional momentum account, will be presented. Is There Evidence for a Novelty-Biased Search Mechanism? Posner and Cohen (1984) conducted an experiment that had three possible target locations, one centrally located on the screen and the other two on either side of the first. Individuals were instructed to keep their eyes at the center location and to respond when they saw a target. During a trial, one of the peripheral locations would be cued by briefly flickering the outline of the box (this box will subsequently be referred to as the cued location), followed after some variable time interval by the target, which could appear in any of the three boxes. The participants were in- 219 Copyright 2004 Psychonomic Society, Inc. This research was supported by an NSERC research grant awarded to Steve Joordens, and by an Ontario Graduate Scholarship awarded to the first author. We thank Steve Joordens and Jay Pratt for their assistance with this work, as well as Tram Neill, John McDonald, Brad Gibson, and an anonymous reviewer for helpful comments on earlier versions of this article. Correspondence concerning this article should be addressed to T. M. Spalek, Department of Psychology, Simon Fraser University, Burnaby, BC, V5A 1S6, Canada (e-mail: [email protected]). Note-This article was accepted by the previous editorial team, headed by Neil Macmillan. Inhibition of return (IOR) refers to the finding that individuals are slower to respond to a target presented at a previously attended location than they are to respond to a target presented at a novel location (Posner & Cohen, 1984). The attentional momentum theory is a recent view of how attention moves around the environment, and it provides an account for the IOR effect that does not rely on an inhibitory mechanism (Pratt, Spalek, & Bradshaw, 1999). The present paper supports the attentional momentum viewpoint in two ways: first, by replicating the finding that reaction times to targets at the uncued locations are not all the same (Pratt et al., 1999) and second, by showing that responses made to all locations on the cued side of fixation, and not just to the locations that attention had previously traversed, are slower than are responses made to locations on the opposite side of fixation. We also demonstrate that there is a directional bias to the IOR effect that results in the effect' s being larger when attention moves in a left-to-right manner
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