756 research outputs found

    What Patients Want to Know about Imaging Examinations: A Multiinstitutional U.S. Survey in Adult and Pediatric Teaching Hospitals on Patient Preferences for Receiving Information before Radiologic Examinations

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    Purpose To identify what information patients and parents or caregivers found useful before an imaging examination, from whom they preferred to receive information, and how those preferences related to patient-specific variables including demographics and prior radiologic examinations. Materials and Methods A 24-item survey was distributed at three pediatric and three adult hospitals between January and May 2015. The χ2 or Fisher exact test (categorical variables) and one-way analysis of variance or two-sample t test (continuous variables) were used for comparisons. Multivariate logistic regression was used to determine associations between responses and demographics. Results Of 1742 surveys, 1542 (89%) were returned (381 partial, 1161 completed). Mean respondent age was 46.2 years ± 16.8 (standard deviation), with respondents more frequently female (1025 of 1506, 68%) and Caucasian (1132 of 1504, 75%). Overall, 78% (1117 of 1438) reported receiving information about their examination most commonly from the ordering provider (824 of 1292, 64%), who was also the most preferred source (1005 of 1388, 72%). Scheduled magnetic resonance (MR) imaging or nuclear medicine examinations (P < .001 vs other examination types) and increasing education (P = .008) were associated with higher rates of receiving information. Half of respondents (757 of 1452, 52%) sought information themselves. The highest importance scores for pre-examination information (Likert scale ≄4) was most frequently assigned to information on examination preparation and least frequently assigned to whether an alternative radiation-free examination could be used (74% vs 54%; P < .001). Conclusion Delivery of pre-examination information for radiologic examinations is suboptimal, with half of all patients and caregivers seeking information on their own. Ordering providers are the predominant and preferred source of examination-related information, with respondents placing highest importance on information related to examination preparation

    Palaeontology and geological context of a Middle Pleistocene faunal assemblage from the Gladysvale Cave, South Africa

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    Palaeontological and geological research at the Gladysvale Cave during the last decade has concentrated on de-roofed deposits located outside the Main Chamber. This area has been termed the Gladysvale External Deposit (GVED) and consists of fossil-rich calcified and decalcified sediments. Here we report on the recent analysis of both the faunal material and the geological context of this deposit. The faunal assemblage, excavated from the decalcified sediments contains 29 mammal species including taxa rare or absent in the Witwatersrand Plio-Pleistocene fossil record (e.g. Pelorovis and Kobus leche). Carnivores and porcupines are identified as accumulating agents of the bones. No new hominin findings can be reported from this deposit, and no cultural remains have been recovered. Geologically the calcified and decalcified breccias represent part of a large talus cone that is relatively unexposed. Uniquely for a cave fill in the Witwatersrand hominin-bearing sites, the sediments are horizontally stratified and form a number of flowstone bound sequences. The dating of the in situ cemented sediments is based on electron spin resonance (ESR) and palaeomagnetism. Recent results indicate that the deposits are of Middle-Pleistocene age.Palaeo-Anthropology Scientific Trust; French Embassy in South Africa; Co-operation and Cultural Service; National Geographic Society; John Nash and family; DACEL; University of the Witwatersrand Research Office and School of Geosciences; World Heritage Site Committee; SAHRA; Swiss National Science Foundation; NSF Grants ILl 9151111 and SBR 989628

    Tetraquarks in a chiral constituent quark model

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    We analyze the possibility of heavy-light tetraquark bound states by means of a chiral constituent quark model. The study is done in a variational approach. Special attention is paid to the contribution given by the different terms of the interacting potential and also to the role played by the different color channels. We find a stable state for both qqcˉcˉqq\bar{c}\bar{c} and qqbˉbˉqq\bar{b}\bar{b} configurations. Possible decay modes of these structures are analyzed.Comment: 13 pages, no figures. Accepted for publication in European Journal of Physics

    Principal forms X^2 + nY^2 representing many integers

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    In 1966, Shanks and Schmid investigated the asymptotic behavior of the number of positive integers less than or equal to x which are represented by the quadratic form X^2+nY^2. Based on some numerical computations, they observed that the constant occurring in the main term appears to be the largest for n=2. In this paper, we prove that in fact this constant is unbounded as n runs through positive integers with a fixed number of prime divisors.Comment: 10 pages, title has been changed, Sections 2 and 3 are new, to appear in Abh. Math. Sem. Univ. Hambur

    Quantising Gravity Using Physical States of a Superstring

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    A symmetric zero mass tensor of rank two is constructed using the superstring modes of excitation which satisfies the physical state constraints of a superstring. These states have one to one correspondence with quantised operators and are shown to be the absorption and emission quanta of the Minkowski space Lorentz tensors using the Gupta-Bleuler method of quantisation. The principle of equivalence makes the tensor identical to the metric tensor at any arbitrary space-time point. The propagator for the quantised field is deduced. The gravitational interaction is switched on by going over from ordinary derivatives to coderivatives.The Riemann-Christoffel affine connections are calculated and the weak field Ricci tensor RΌΜ0R^{0}_{\mu \nu} is shown to vanish. The interaction part RΌΜintR^{int}_{\mu \nu} is found out and the exact RΌΜR_{\mu \nu} of theory of gravity is expressed in terms of the quantised metric. The quantum mechanical self energy of the gravitational field, in vacuum, is shown to vanish. It is suggested that quantum gravity may be renormalisable by the use of the physical ground states of the superstring theory.Comment: 14 page

    Catecholaminergic manipulation alters dynamic network topology across cognitive states

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    The human brain is able to flexibly adapt its information processing capacity to meet a variety of cognitive challenges. Recent evidence suggests that this flexibility is reflected in the dynamic reorganization of the functional connectome. The ascending catecholaminergic arousal systems of the brain are a plausible candidate mechanism for driving alterations in network architecture, enabling efficient deployment of cognitive resources when the environment demands them. We tested this hypothesis by analyzing both resting-state and task-based fMRI data following the administration of atomoxetine, a noradrenaline reuptake inhibitor, compared with placebo, in two separate human fMRI studies. Our results demonstrate that the manipulation of central catecholamine levels leads to a reorganization of the functional connectome in a manner that is sensitive to ongoing cognitive demands. There is emerging evidence that the flexible network structure of the brain is related to activity within the ascending arousal systems of the brain, such as the noradrenergic locus coeruleus. Here, we explored the role of catecholaminergic activity on network architecture by analyzing the graph structure of the brain measured using functional MRI following the administration of atomoxetine, a selective noradrenaline reuptake inhibitor. We estimated functional network topology in two double-blind, placebo-controlled datasets: one from the resting state and another from a parametric N-back task. Our results demonstrate that the nature of catecholaminergic network reconfiguration is differentially related to cognitive state and provide confirmatory evidence for the hypothesis that the functional network signature of the brain is sensitive to the ascending catecholaminergic arousal system

    Moral Objectivism in Cross-Cultural Perspective

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    Moral psychologists have recently turned their attention to the study of folk metaethical beliefs. We report the results of a cross-cultural study using Chinese, Polish and Ecuadorian participants that seeks to advance this line of investigation. Individuals in all three demographic groups were observed to attribute objectivity to ethical statements in very similar patterns. Differences in participants’ strength of opinion about an issue, the level of societal agreement or disagreement about an issue, and participants’ age were found to significantly affect their inclination to view the truth of an ethical statement as a matter of objective fact. Implications for theorizing about folk morality are discussed

    Doxycycline post-exposure prophylaxis for sexually transmitted infections in South Africa

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    Data availability This opinion paper does not contain original data for sharing. References are included for all the data mentioned in the manuscript.DATA AVAILABILITY : This opinion paper does not contain original data for sharing. References are included for all the data mentioned in the manuscript.South Africa has a large burden of bacterial sexually transmitted infections (STIs) with high rates among men who have sex with men (MSM). Randomised controlled trials have recently demonstrated high effectiveness of doxycycline post-exposure prophylaxis (PEP) for prevention of bacterial STIs in MSM, with 70% – 85% reductions in Chlamydia trachomatis infection and syphilis, and approximately 50% reduction in Neisseria gonorrhoeae infection. Doxycycline PEP was not demonstrated to be effective in reducing C. trachomatis and N. gonorrhoeae infection among Kenyan cisgender women. Although no worrisome trends in antimicrobial resistance (AMR) were observed in the trials, important concerns remain about doxycycline PEP and AMR development in STIs, other pathogens, commensals, and the microbiome. Tetracycline resistance in N. gonorrhoeae is already widespread in South Africa, but emergence of AMR in other STIs would be concerning. Larger sample sizes of doxycycline PEP users with longer follow-up time are needed to understand the impact that doxycycline PEP may have on AMR at individual and population level. In this opinion article, we weigh the benefits of doxycycline PEP for prevention of bacterial STIs against the existing AMR concerns and data gaps in the South African context. Based on the current evidence, we conclude that it would be reasonable to offer doxycycline PEP to high-risk MSM on a case-by-case basis, provided that it is offered by experienced sexual health clinicians in settings that have access to diagnostic STI testing and ongoing AMR surveillance.http://www.sajhivmed.org.zaam2024Medical MicrobiologySDG-03:Good heatlh and well-bein

    Doxycycline post-exposure prophylaxis for sexually transmitted infections in South Africa

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    South Africa has a large burden of bacterial sexually transmitted infections (STIs) with high rates among men who have sex with men (MSM). Randomised controlled trials have recently demonstrated high effectiveness of doxycycline post-exposure prophylaxis (PEP) for prevention of bacterial STIs in MSM, with 70% – 85% reductions in Chlamydia trachomatis infection and syphilis, and approximately 50% reduction in Neisseria gonorrhoeae infection. Doxycycline PEP was not demonstrated to be effective in reducing C. trachomatis and N. gonorrhoeae infection among Kenyan cisgender women. Although no worrisome trends in antimicrobial resistance (AMR) were observed in the trials, important concerns remain about doxycycline PEP and AMR development in STIs, other pathogens, commensals, and the microbiome. Tetracycline resistance in N. gonorrhoeae is already widespread in South Africa, but emergence of AMR in other STIs would be concerning. Larger sample sizes of doxycycline PEP users with longer follow-up time are needed to understand the impact that doxycycline PEP may have on AMR at individual and population level. In this opinion article, we weigh the benefits of doxycycline PEP for prevention of bacterial STIs against the existing AMR concerns and data gaps in the South African context. Based on the current evidence, we conclude that it would be reasonable to offer doxycycline PEP to high-risk MSM on a case-by-case basis, provided that it is offered by experienced sexual health clinicians in settings that have access to diagnostic STI testing and ongoing AMR surveillance
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