1,305 research outputs found
Interfacial States in DonorâAcceptor Organic Heterojunctions: Computational Insights into Thiophene-Oligomer/Fullerene Junctions
Donorâacceptor heterojunctions composed of thiophene oligomers and C60 fullerene were investigated with computational methods. Benchmark calculations were performed with time-dependent density functional theory. The effects of varying the density functional, the number of oligomers, the intermolecular distance, the medium polarization, and the chemical functionalization of the monomers were analyzed. The results are presented in terms of diagrams where the electronic states are classified as locally excited states, charge-transfer states, and delocalized states. The effects of each option for computational simulations of realistic heterojunctions employed in photovoltaic devices are evaluated and discussed
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Nearest neighbor analysis in one dimension
Since its initial presentation by Clark and Evans, nearest neighbor analysis for spatial randomness has gained considerable popularity in fields as diverse as geography, ecology, archaeology, cell biology, forestry, meteorology, and epidemiology. Epidemiologists are often interested in determining whether disease cases are clustered, dispersed, or randomly distributed, since different patterns of disease incidence over time or space can provide dues to the etiology of the disease. An environmental hazard or a transmissable agent can produce a cluster of disease events, i.e. a set of events occurring unusually dose to each other in time, space, or both time and space. In spite of its wide applicability, few attempts have been made to adapt the nearest neighbor method to the analysis of points distributed along a line. This report outlines the theoretical derivation of the moments of the mean nearest neighbor distance in the one dimension case and the correction of its expected value in order to overcome the boundary problem. It presents the derivation of the moments of order statistics, for specific sample sizes and for the general case. These results are then used for the derivation of the moments of nearest neighbor distances, and for the derivation of the moments of the mean nearest neighbor distance. Then the boundary problem and an examination of five alternative ways to compensate for it in the calculation of the expected value of the mean nearest neighbor distance are discussed. Finally, the results from a large scale computer simulation which compares the various correction methods are presented
Geometric realizations of curvature models by manifolds with constant scalar curvature
We show any Riemannian curvature model can be geometrically realized by a
manifold with constant scalar curvature. We also show that any pseudo-Hermitian
curvature model, para-Hermitian curvature model, hyper-pseudo-Hermitian
curvature model, or hyper-para-Hermitian curvature model can be realized by a
manifold with constant scalar and *-scalar curvature
Preoxygenation and prevention of desaturation during emergency airway management,â
Patients requiring emergency airway management are at great risk of hypoxemic hypoxia because of primary lung pathology, high metabolic demands, anemia, insufficient respiratory drive, and inability to protect their airway against aspiration. Tracheal intubation is often required before the complete information needed to assess the risk of periprocedural hypoxia is acquired, such as an arterial blood gas level, hemoglobin value, or even a chest radiograph. This article reviews preoxygenation and peri-intubation oxygenation techniques to minimize the risk of critical hypoxia and introduces a risk-stratification approach to emergency tracheal intubation. Techniques reviewed include positioning, preoxygenation and denitrogenation, positive end expiratory pressure devices, and passive apneic oxygenation. [Ann Emerg Med. 2011;xx:xxx.
Working up rectal bleeding in adult primary care practices
Rationale, aims and objectivesVariation in the workup of rectal bleeding may result in guidelineâdiscordant care and delayed diagnosis of colorectal cancer. Accordingly, we undertook this study to characterize primary care cliniciansâ initial rectal bleeding evaluation.MethodsWe studied 438 patients at 10 adult primary care practices affiliated with three Boston, Massachusetts, academic medical centres and a multispecialty group practice, performing medical record reviews of subjects with visit codes for rectal bleeding, haemorrhoids or bloody stool. Nurse reviewers abstracted patientsâ sociodemographic characteristics, rectal bleedingârelated symptoms and components of the rectal bleeding workup. Bivariate and multivariable logistic regression models examined factors associated with guidelineâdiscordant workups.ResultsClinicians documented a family history of colorectal cancer or polyps at the index visit in 27% of cases and failed to document an abdominal or rectal examination in 21% and 29%. Failure to order imaging or a diagnostic procedure occurred in 32% of cases and was the only component of the workup associated with guidelineâdiscordant care, which occurred in 27% of cases. Compared with patients at hospitalâbased teaching sites, patients at urban clinics or community health centres had 2.9 (95% confidence interval 1.3â6.3) times the odds of having had an incomplete workup. Network affiliation was also associated with guideline concordance.ConclusionWorkup of rectal bleeding was inconsistent, incomplete and discordant with guidelines in oneâquarter of cases. Research and improvements strategies are needed to understand and manage practice and provider variation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136454/1/jep12596.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136454/2/jep12596_am.pd
UK science press officers, professional vision and the generation of expectations
Science press officers can play an integral role in helping promote expectations and hype about biomedical research. Using this as a starting point, this article draws on interviews with 10 UK-based science press officers, which explored how they view their role as science reporters and as generators of expectations. Using Goodwinâs notion of âprofessional visionâ, we argue that science press officers have a specific professional vision that shapes how they produce biomedical press releases, engage in promotion of biomedical research and make sense of hype. We discuss how these insights can contribute to the sociology of expectations, as well as inform responsible science communication.This project was funded by the Wellcome Trust (Wellcome Trust Biomedical Strategic Award 086034)
Preoxygenation and prevention of desaturation during emergency airway management,â
Patients requiring emergency airway management are at great risk of hypoxemic hypoxia because of primary lung pathology, high metabolic demands, anemia, insufficient respiratory drive, and inability to protect their airway against aspiration. Tracheal intubation is often required before the complete information needed to assess the risk of periprocedural hypoxia is acquired, such as an arterial blood gas level, hemoglobin value, or even a chest radiograph. This article reviews preoxygenation and peri-intubation oxygenation techniques to minimize the risk of critical hypoxia and introduces a risk-stratification approach to emergency tracheal intubation. Techniques reviewed include positioning, preoxygenation and denitrogenation, positive end expiratory pressure devices, and passive apneic oxygenation
Patientsâ use of information about medicine side effects in relation to experiences of suspected adverse drug reactions
Background
Adverse drug reactions (ADRs) are common, and information about medicines is increasingly widely available to the public. However, relatively little work has explored how people use medicines information to help them assess symptoms that may be suspected ADRs.
Objective
Our objective was to determine how patients use patient information leaflets (PILs) or other medicines information sources and whether information use differs depending on experiences of suspected ADRs.
Method
This was a cross-sectional survey conducted in six National Health Service (NHS) hospitals in North West England involving medical in-patients taking at least two regular medicines prior to admission. The survey was administered via a questionnaire and covered use of the PIL and other medicines information sources, perceived knowledge about medicines risks/ADRs, experiences of suspected ADRs, plus demographic information.
Results
Of the 1,218 respondents to the survey, 18.8 % never read the PIL, whilst 6.5 % only do so if something unexpected happens. Educational level was related to perceived knowledge about medicines risks, but not to reading the PIL or seeking further information about medicines risks. Over half the respondents (56.0 %) never sought more information about possible side effects of medicines. A total of 57.2 % claimed they had experienced a suspected ADR. Of these 85.9 % were either very sure or fairly sure this was a reaction to a medicine. Over half of those experiencing a suspected ADR (53.8 %) had read the PIL, of whom 36.2 % did so before the suspected ADR occurred, the remainder afterwards. Reading the PIL helped 84.8 % of these respondents to decide they had experienced an ADR. Educational level, general knowledge of medicines risks and number of regular medicines used all increased the likelihood of experiencing an ADR.
Conclusion
More patients should be encouraged to read the PIL supplied with medicines. The results support the view that most patients feel knowledgeable about medicines risks and suspected ADRs and value information about side effects, but that reading about side effects in PILs or other medicines information sources does not lead to experiences of suspected ADRs
Conceptions and expectations of research collaboration in the European social sciences: Research policies, institutional contexts and the autonomy of the scientific field
This paper investigates the interactions between policy drivers and academic practice in international research collaboration. It draws on the case of the Open Research Area (ORA), a funding scheme in the social sciences across four national research agencies, seeking to boost collaboration by supporting âintegratedâ projects. The paper discusses the schemeâs governance and its place within the European policy space before turning to awarded researchersâ perceptions of its originality and impact on their projectâs emergence and development. Drawing on Bourdieuâs field theory, we analyse the schemeâs capacity to challenge researchersâ habitual collaborative practice as well as the hierarchical foundations of the social science field. We relate the discourses of researchers, located in France, Germany, the Netherlands and the United Kingdom, to such structural dimensions of the academic profession as, disciplinary cultures, institutional environments and national performance management of research careers. The paper argues that the ORA introduces novel mechanisms of power sharing and answerability in social sciences research capable of unsettling the autonomy of the scientific field. This analysis offers a new perspective on the often unquestioned superiority of the model of international collaboration induced by schemes such as ORA
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