4,654 research outputs found
American postmodernist fiction and the past by Theophilus Savvas
A review of American Postmodernist Fiction and the Past by Theophilus Savva
Simple modeling of self-oscillation in Nano-electro-mechanical systems
We present here a simple analytical model for self-oscillations in
nano-electro-mechanical systems. We show that a field emission self-oscillator
can be described by a lumped electrical circuit and that this approach is
generalizable to other electromechanical oscillator devices. The analytical
model is supported by dynamical simulations where the electrostatic parameters
are obtained by finite element computations.Comment: accepted in AP
Emotional labour and wellbeing: what protects nurses?
Although compassionate care has wide-ranging benefits for patients, it can be emotionally demanding for healthcare staff. This may be a particular problem for those with little experience in a caring role. This study utilises the job demands-resources model to examine links between “emotional labour” and emotional exhaustion in student nurses. In line with the triple-match principle—whereby interactive effects are more likely when job demands, resources, and outcomes are within the same qualitative domain—the protective role of emotional support and emotion-focused coping (i.e., emotional venting) in the relationship between emotional labour and exhaustion is also explored. An online questionnaire was completed by 351 student nurses with experience working in healthcare settings. A strong positive relationship was found between emotional labour and emotional exhaustion, and some support was found for the moderating effects of emotional support and emotion-focused coping. Ways to help student and qualified nurses develop the emotional resilience required to protect their wellbeing, while providing high-quality compassionate care to patients are considered
Profile of patients diagnosed with AIDS at age 60 and above in Brazil, from 1980 until June 2009, compared to those diagnosed at age 18 to 59.
OBJECTIVES: The aim of this study was to learn more about people diagnosed with acquired immunodeficiency syndrome (AIDS) at age 60 and above in Brazil, and to compare them with people diagnosed at a younger age. METHODS: This study was based on the analysis of secondary data from the Brazilian AIDS Program. The study population consisted of people diagnosed with AIDS at age 60 and above. The comparison group was comprised of a 20% random sample of people diagnosed at age 18 to 59, frequency-matched by year of diagnosis. RESULTS: 544,846 cases of AIDS were reported in Brazil from 1980 until June 2009. Over 90% of cases were diagnosed between 18 and 59 years of age, and 13,657 (2.5%) at age 60 and above. The first case of AIDS among the elderly was reported in 1984. The comparison group consisted of 101,528 patients. Gender proportion was similar for both groups, and the proportion of people identified with AIDS after death in the Brazilian Mortality Information System (SIM) was 4% higher among the elderly. Both groups were also similar regarding the region of residence; a markedly higher proportion lived in Southeastern Brazil. Older people were more likely to have lower education and to have contracted AIDS by heterosexual contact, and less likely to be intravenous drug users. Male to female ratio among those diagnosed with AIDS at or above age 60 decreased over the years, in the same way as observed for the whole cohort. Mortality was higher among men in both groups. CD4 category (taken closest to the date of AIDS diagnosis) was very similar in both groups. CONCLUSION: The characteristics of the epidemic among the elderly show similarities to the younger group considering gender distribution and CD4 category, but differ regarding educational level and exposure category. Also, the elderly were more likely not to have their AIDS condition promptly diagnosed
Algorithms for Contractibility of Compressed Curves on 3-Manifold Boundaries
In this paper we prove that the problem of deciding contractibility of an arbitrary closed curve on the boundary of a 3-manifold is in NP. We emphasize that the manifold and the curve are both inputs to the problem. Moreover, our algorithm also works if the curve is given as a compressed word. Previously, such an algorithm was known for simple (non-compressed) curves, and, in very limited cases, for curves with self-intersections. Furthermore, our algorithm is fixed-parameter tractable in the complexity of the input 3-manifold.
As part of our proof, we obtain new polynomial-time algorithms for compressed curves on surfaces, which we believe are of independent interest. We provide a polynomial-time algorithm which, given an orientable surface and a compressed loop on the surface, computes a canonical form for the loop as a compressed word. In particular, contractibility of compressed curves on surfaces can be decided in polynomial time; prior published work considered only constant genus surfaces. More generally, we solve the following normal subgroup membership problem in polynomial time: given an arbitrary orientable surface, a compressed closed curve ?, and a collection of disjoint normal curves ?, there is a polynomial-time algorithm to decide if ? lies in the normal subgroup generated by components of ? in the fundamental group of the surface after attaching the curves to a basepoint
The variant course of the suprascapular artery
The suprascapular artery (SSA) has been identified to be of clinical relevance in surgical intervention and fracture healing of the shoulder. Despite the classic description of its course and relation to the superior transverse scapular ligament, it is subject to much variation. The aims of this study were: (i) to describe the course of the SSA in relation to the superior transverse scapular ligament, (ii) tob determine the prevalence of the course of the SSA in relation to the superior transverse scapular ligament, (iii) to determine the prevalence of the variant origin of the SSA in cases presenting with variant course of the latter, and (iv) to establish a difference in laterality and that between adults and foetuses. The course of the SSA was investigated through the macro- and micro dissection of the antero-andpostero-superior shoulder regions of 31 adult and 19 foetal cadaveric specimens (n = 100). The SSA was observed to pass inferior to the superior transverse scapular ligament accompanied by the suprascapular nerve (20%), which corroborated the findings of previous studies. Subsequently, this variant course of the SSA also appeared to present with the variant origin of it in many instances (13%): from the 3rd part of the subclavian artery (4%), 1st part of the axillary artery (2%), 2nd part of the axillary artery (5%) and SSA (2%). Injury to the SSA may cause more serious trauma than that of arteries which are isolated from the great vessels, therefore the recognition and knowledge of variation in the origin and course of the SSA is significant in the treatment of diseases in the shoulder and cervical regions. Furthermore, the accompaniment of the suprascapular nerve with the SSA at the suprascapular notch inferior to the superior transverse scapular ligament may lead to neuropathy syndromes due to the pulsation of the artery against the nerve within the confined notch
An anatomical investigation of the superficial and deep palmar arches
Background: The superficial palmar arch (SPA) and deep palmar arch (DPA) provide the dominant vascular supply to the hand. The SPA is considered to be highly variable and can be classified as either complete or incomplete. The simplest definition states that the anastomosis between the vessels contributing to the arch represent a complete arch, while an incomplete arch is described as characterised by an absence of anastomosis between the vessels contributing to it. This study aimed to describe the anatomical landmarks, formation and branching patterns of the SPA and DPA. In this study, the SPA and DPA were dissected in 50 specimens (n = 100 adult hands), respectively.
Materials and methods: A complete SPA was observed in 92% of specimens and classified into three types. In Type A (44%), the SPA was formed by the anastomosis of the superficial palmar branch of the radial artery with the ulnar artery. Type B (46%) was formed by the ulnar artery alone and Type C (2%) was formed by anastomosis of the ulnar artery with the superficial palmar branch of the radial artery and the persistent median artery.
Results: An incomplete SPA was observed in 8% of the specimens and divided into three types formed by the radial and ulnar arteries. The DPA was divided into five types viz. Type G (72%), where the DPA was formed by anastomosis of the deep palmar branch of the radial artery (DPBRA) with the deep palmar branch of the ulnar artery (DPBUA). Type H (12%), was formed by anastomosis of the DPBRA, the DBUA and the interosseous artery. Type I (8%), was formed by the anastomosis of the DPBRA with the superior and inferior DPBUA. Type J (4%), the deep ulnar artery had two branches whereby either one branch anastomosed with the DPBRA to form the DPA. Type K (4%), the DBUA exhibited two deep branches with one branch anastomosing with the DPBRA to complete the DPA.
Conclusions: The interosseous artery anastomosed with either the DPA or the additional DPBUA. Knowledge of the variability of the SPA and DPA is crucial for safe and successful hand surgeries.
The Production Gap Report: 2020 Special Report
To follow a 1.5°C-consistent pathway, the world will need to decrease fossil fuel production by roughly 6% per year between 2020 and 2030. Countries are instead planning and projecting an average annual increase of 2%, which by 2030 would result in more than double the production consistent with the 1.5°C limit
Interaction of Stress, Lead Burden, and Age on Cognition in Older Men: The VA Normative Aging Study
BACKGROUND. Low-level exposure to lead and to chronic stress may independently influence cognition. However, the modifying potential of psychosocial stress on the neurotoxicity of lead and their combined relationship to aging-associated decline have not been fully examined. OBJECTIVES. We examined the cross-sectional interaction between stress and lead exposure on Mini-Mental State Examination (MMSE) scores among 811 participants in the Normative Aging Study, a cohort of older U.S. men. METHODS. We used two self-reported measures of stress appraisal-a self-report of stress related to their most severe problem and the Perceived Stress Scale (PSS). Indices of lead exposure were blood lead and bone (tibia and patella) lead. RESULTS. Participants with higher self-reported stress had lower MMSE scores, which were adjusted for age, education, computer experience, English as a first language, smoking, and alcohol intake. In multivariable-adjusted tests for interaction, those with higher PSS scores had a 0.57-point lower (95% confidence interval, -0.90 to 0.24) MMSE score for a 2-fold increase in blood lead than did those with lower PSS scores. In addition, the combination of high PSS scores and high blood lead categories on one or both was associated with a 0.05-0.08 reduction on the MMSE for each year of age compared with those with low PSS score and blood lead level (p < 0.05). CONCLUSIONS. Psychological stress had an independent inverse association with cognition and also modified the relationship between lead exposure and cognitive performance among older men. Furthermore, high stress and lead together modified the association between age and cognition.National Institutes of Health (R01ES07821, R01HL080674, R01HL080674-02S1, R01ES013744, ES05257-06A1, P20MD000501, P42ES05947, ES03918-02); National Center for Research Resources General Clinical Research Center (M01RR02635); Leaves of Grass Foundation; United States Department of Veterans Affair
Generating socially appropriate tutorial dialog
Analysis of student-tutor coaching dialogs suggest that good human tutors attend to and attempt to influence the motivational state of learners. Moreover, they are sensitive to the social face of the learner, and seek to mitigate the potential face threat of their comments. This paper describes a dialog generator for pedagogical agents that takes motivation and face threat factors into account. This enables the agent to interact with learners in a socially appropriate fashion, and foster intrinsic motivation on the part of the learner, which in turn may lead to more positive learner affective states
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