bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface‐flux‐induced tropical cyclogenesis within an axisymmetric atmospheric balanced model
Authors: Frisius T. 
Published: January 2007

AbstractThe WISHE (wind‐induced surface heat exchange) instability theory for tropical atmospheric disturbances suggests that maximum warming occurs at the position of maximum surface wind. Applying this concept to axisymmetric cyclones leads to outward migration of the radius of maximum wind without amplification. Therefore, the fundamental WISHE feedback loop cannot explain tropical cyclogenesis on its own. Additional restrictions for the surface‐flux‐induced heating are necessary.This study investigates in detail the effect of such restrictions on surface‐flux‐induced tropical cyclogenesis within the framework of a simple axisymmetric balanced model previously developed by the author. This model is based on the assumption of zero potential vorticity and formulated in potential‐radius coordinates. Heating is restricted by an efficiency parameter β that was previously introduced by Emanuel in a similar but more simplified model to account for the reduction of net latent heating in an unsaturated atmosphere. As in Emanuel's model it is found in the linearized and in the nonlinear model that a negative gradient of the efficiency parameter is necessary to initiate tropical cyclogenesis. In this case, wind amplification primarily takes place in the region where the gradient of the efficiency parameter is negative. This region migrates inward, shrinks due to frontogenesis and becomes the tropical cyclone's eyewall. It is shown that cyclogenesis becomes possible even when the surface heat exchange is wind‐speed independent. In the case of a zero β‐gradient outward propagation with no amplification takes place. If a cold anomaly is present at the vortex centre, the wind speed increases slightly but no cyclogenesis occurs. If on the other hand moisture fluxes can modify the initially uniform β‐profile, cyclogenesis appears after anegative β‐gradient is established. Horizontal diffusion is necessary to prevent a frontal collapse during the development and acts to transport momentum to regions where no wind is generated by heating. However, inward momentum diffusion does not accelerate the development as it was found previously in the model of Emanuel. This cyclogenesis process can already be qualitatively reproduced analytically by the linearized version of the model which additionally includes horizontal diffusion effects. Copyright © 2006 Royal Meteorological Society
Vertical discretizations giving optimal representation of normal modes: Sensitivity to the form of the pressure‐gradient term
Authors: Thuburn J. 
Published: January 2007

AbstractThe normal‐mode dispersion properties and structures of some vertical discretizations of the compressible Euler equations are re‐examined. It is shown that the dispersion properties can be sensitive to the form in which the pressure‐gradient term is expressed. For a height coordinate and for an isentropic vertical coordinate, discretizations are identified that have optimal dispersion properties and, at the same time, lend themselves to mass conservation by predicting the relevant density variable. Copyright © 2006 Royal Meteorological Society
The seasonal cycle in the lower troposphere over West Africa from sounding observations
Authors: Zhang Chidong , Woodworth Phoebe , Gu Guojun 
Published: January 2007

AbstractIn situ sounding observations from selected sites in West and Central Africa were used to document the seasonal cycle in the lower troposphere associated with the annual migration of precipitation. The main purpose of this exercise is to provide a description of the seasonal cycle free of the errors and biases of numerical models, which can be substantial in this region. Many features in the circulation typically associated with the West African Monsoon (WAM) exist through almost the entire seasonal cycle in the region. The low‐level easterly jet, known as the African Easterly Jet during the monsoon season, remains prominent and closely related to the rain band in other phases of the seasonal cycle, even when the rain band is located near the equator. The surface southerly monsoon onshore flow penetrates through the rain band in the entire season cycle. The depth of the southerly surface monsoon flow undergoes a seasonal variation, and is greatest during the peak season of the monsoon. A unique feature is a low‐level (∼700 hPa) northerly flow penetrating through the rain band in various phases of the seasonal cycle. Risking possible biases of land‐bound sounding data, these observations are synthesized into a schematic describing the salient features in the low‐level circulation associated with the rain band in different phases of the seasonal cycle. This synthesized circulation pattern in West Africa is in contrast to the traditional conceptual circulation pattern associated with the marine ITCZ and other monsoon systems. The results from this study call for more research attention to the low‐level meridional circulation for a full understanding of the dynamics of the WAM. This study also advocates the study of the WAM to be conducted in a broad context of the seasonal cycle in the region and in comparison to the marine ITCZ. Copyright © 2006 Royal Meteorological Society
Appraising qualitative research for inclusion in systematic reviews: a quantitative and qualitative comparison of three methods
Authors: Dixon-Woods Mary , Sutton Alex , Shaw Rachel , Miller Tina , Smith Jonathan , Young Bridget , Bonas Sheila , Booth Andrew , Jones David 
Published: January 2007

Objective: Qualitative research is increasingly valued as part of the evidence for policy and practice, but how it should be appraised is contested. Various appraisal methods, including checklists and other structured approaches, have been proposed but rarely evaluated. We aimed to compare three methods for appraising qualitative research papers that were candidates for inclusion in a systematic review of evidence on support for breast-feeding. Method: A sample of 12 research papers on support for breast-feeding was appraised by six qualitative reviewers using three appraisal methods: unprompted judgement, based on expert opinion; a UK Cabinet Office quality framework; and CASP, a Critical Appraisal Skills Programme tool. Papers were assigned, following appraisals, to 1 of 5 categories, which were dichotomized to indicate whether or not papers should be included in a systematic review. Patterns of agreement in categorization of papers were assessed quantitatively using κ statistics, and qualitatively using cross-case analysis. Results: Agreement in categorizing papers across the three methods was slight ( κ =0.13; 95% CI 0.06–0.24). Structured approaches did not appear to yield higher agreement than that by unprompted judgement. Qualitative analysis revealed reviewers' dilemmas in deciding between the potential impact of findings and the quality of the research execution or reporting practice. Structured instruments appeared to make reviewers more explicit about the reasons for their judgements. Conclusions: Structured approaches may not produce greater consistency of judgements about whether to include qualitative papers in a systematic review. Future research should address how appraisals of qualitative research should be incorporated in systematic reviews.
Waiting for cataract surgery – effects of a maximum waiting-time guarantee
Authors: Hanning Marianne , Lundström Mats 
Published: January 2007

Objective: To evaluate the effects of the Maximum Waiting-time Guarantee (MWG) policy for cataract surgery on volume, indications, waiting times and priority setting in Sweden. Methods: Comparison between 1993 and 1994, when the guarantee had been in force for one year, and 1998 and 1999, when the policy had been terminated for one year. Data from the National Cataract Registry covering 156,657 cataract operations for the years studied. Results: The number of operations increased by 43% between the two study periods. Of this increase, 61% were patients with a visual acuity above 0.5 in the better eye, i.e. low-priority patients. Waiting times were longer for all patient categories in the later period and differences in waiting times between patients with differing priority diminished. Variations among the units in priority setting and waiting times were substantial, and increased after the Guarantee was terminated. Conclusions: The Guarantee with its explicit indications was an effective policy instrument to limit waiting times and improve access for patients with the greatest need. It is unlikely that the Guarantee caused any 'crowding out' of other patient groups. When the Guarantee was not in force, indications for surgery widened. This, however, resulted in longer waiting times for all patient groups. After the Guarantee was terminated, the already substantial differences in access and indications among ophthalmic units became even greater.
Racial variations in the choice of on-pump versus off-pump coronary artery bypass grafting
Authors: Mukamel Dana , Glance Laurent , Weimer David , Pearson Thomas , Massey Todd , Gold Jeffery , Greenfield Sheldon , Jackson James , Mushlin Alvin 
Published: January 2007

Objective: To examine explanations of differences in utilization rates of a newly reintroduced technique – off-pump coronary artery bypass grafting (CABG) – between racial minorities and Whites. Method: The study was based on 15,313 CABG patients in the New York State Cardiac Surgery Reporting System covering all cardiac surgeons providing off-pump CABG in New York State. We estimated cross sectional, random effect regression models predicting the probability of off-pump versus on-pump surgery. Results: Thirty one percent of Blacks, 20.7% of other races, and 23% of Whites underwent off-pump CABG ( P <0.0001). The higher rates for Blacks arose mostly from being treated by surgeons performing only a few off-pump procedures rather than from surgeons performing many off-pump surgeries. After adjusting for clinical characteristics and coronary anatomy, Blacks treated by surgeons with low volume off-pump procedures were 1.9 times ( P <0.01) more likely to have off-pump surgery compared with Whites treated by the same surgeons. There were no significant differences between Blacks and Whites treated by high volume surgeons. Conclusions: These findings suggest that surgeons who are inexperienced with the off-pump techniques are more likely to perform this surgery on Black patients. Further research should examine potential explanations and the agenda addressing racial disparities should be expanded to address issues of treatment decisions.
Are gatekeepers to renal services referring patients equitably?
Authors: Kee Frank , Reaney Elizabeth , Savage Gerard , O'Reilly Dermot , Patterson Chris , Maxwell Peter , Fogarty Damian ,   The Northern Ireland Targeting Social Need Renal Group
Published: January 2007

Objective: Patients with chronic kidney disease (CKD) benefit from specialist interventions to retard progression of renal failure and prevent cardiovascular events. Certain patient groups have poor access to specialist renal services when dialysis is required. This study used a population-based laboratory database to investigate access to and timeliness of referral to renal specialists relatively early in the course of the disease. Methods: All tests for serum creatinine and haemoglobin (Hb) A1c in Northern Ireland in a two-year period (2001 and 2002) were retrieved for 345,441 adults. Of these, 16,856 patients had at least one serum creatinine level above 150 μmol/L in 2001 not deemed to be due to acute renal failure (crude prevalence 1.42%). This cohort was followed until the end of 2002 and the differences in the time to referral to a specialist were assessed using Cox's proportional hazards regression. Results: Diabetic patients, older patients and those living in deprived areas were significantly more likely to have serum creatinine testing, compared with non-diabetic, younger and those living in more affluent areas. Delays in referral to renal specialists for patients with raised serum creatinine levels were significantly shorter among diabetic patients, women, younger individuals, those living in rural areas, those living close to renal centres and those living in deprived areas. Overall, only 19% of diabetic patients and 6% of non-diabetic patients who had CKD had seen a renal specialist within 12 months of their index creatinine test. Conclusion: Contrary to other diseases, disadvantaged patients do not seem to be under-investigated for renal disease compared with their more affluent neighbours and are generally referred earlier for specialist assessment. However, the absolute rate of timely specialist assessment is low. Recent changes in referral criteria for CKD will result in more referrals and will have serious resource implications. Opportunities for health gain among patients with declining renal function are being missed, particularly among the old and those living furthest from specialist centres.
A comparison of self-reported and observational work sampling techniques for measuring time in nursing tasks
Authors: Ampt Amanda , Westbrook Johanna , Creswick Nerida , Mallock Nadine 
Published: January 2007

Objectives: To compare self-reported and observational work sampling techniques when applied to ward-based nurses. Methods: A self-reported work sampling study was undertaken with nine registered nurses in an Australian teaching hospital over 8.5 weeks, followed by an observational work sampling study conducted over 4.5 weeks. Both studies used a random reminder method and a multidimensional work task classification. Field notes were also recorded and analysed. Results: 3910 data points were collected, 667 during the self-report study and 3243 in the observational study. The two techniques yielded significant differences in work patterns of registered nurses. The observational study showed that compared with the self-reported study, patient care (40% versus 33%, P <0.000) and ward-related activities (7% versus 3%; P <0.001) were recorded significantly more frequently, and documentation less frequently (8% versus 19%; P <0.000). Both the techniques generated similar proportions of time spent in breaks (12%), medication tasks (13%) and clinical discussion (15%). The self-report technique was poorly accepted by nursing staff. The observational technique was well accepted and data collection was more effcient. Conclusions: The self-report work sampling technique is not a reliable method for obtaining an accurate reflection of the work tasks of ward-based nurses. The observational technique was preferred by nurses, and despite concern regarding a potential Hawthorne effect, this was not substantiated.
The credibility of health economic models for health policy decision-making: the case of population screening for abdominal aortic aneurysm
Authors: Campbell Helen , Briggs Andrew , Buxton Martin , Kim Lois , Thompson Simon 
Published: January 2007

Objectives: To review health economic models of population screening for abdominal aortic aneurysm (AAA) among elderly males and assess their credibility for informing decision-making. Methods: A literature review identified health economic models of ultrasound screening for AAA. For each model focussing on population screening in elderly males, model structure and input parameter values were critically appraised using published good practice guidelines for decision analytic models. Results: Twelve models published between 1989 and 2003 were identified. Converting costs to a common currency and base year, substantial variability in cost-effectiveness results were revealed. Appraisals carried out for the nine models focusing on population screening showed differences in their complexity, with the simpler models generating results most favourable to screening. Eight of the nine models incorporated two or more simplifying structural assumptions favouring screening; uncertainty surrounding these assumptions was not investigated by any model. Quality assessments on a small number of parameters revealed input values varied between models, methods used to identify and incorporate input data were often not described, and few sensitivity analyses were reported. Conclusions: Large variation exists in the cost-effectiveness results generated by AAA screening models. The substantial number of factors potentially contributing to such disparities means that reconciliation of model results is impossible. In addition, poor reporting of methods makes it difficult to identify the most plausible and thus most useful model of those developed.
Developing attributes and levels for discrete choice experiments using qualitative methods
Authors: Coast Joanna , Horrocks Sue 
Published: January 2007

Objectives: The rigour with which the first two stages of discrete choice experiments (attribute development and the choice of levels of these attributes) are generally conducted is questionable. This paper provides a case study describing how attributes and their levels were developed for a study of access to dermatology specialist services for non-urgent skin conditions. Methods: Semi-structured interviews were conducted with 19 dermatology patients with non-urgent skin conditions. Informants were purposively sampled for maximum variation and interviews continued until all attributes were fully and clearly defined. An iterative approach was used with data collection and analysis proceeding concurrently. Results: The interviews and parallel analysis generated three iterations. The first iteration comprised early exploratory work with expertise and waiting time emerging as important to informants. The second iteration continued to emphasize these attributes, but individualized care and convenience were added. By the end of the third iteration all attributes were fully elaborated. Conclusions: Qualitative methods enabled attributes to be defined. There was clear tension between the aim in qualitative work to explore and describe, and the reductiveness needed to encapsulate the different aspects of the service within a minimum number of attributes for use in the discrete choice modelling. Improved reporting of the methods of attribute development in all discrete choice experiments is required.
Local Violence, National Peace? Postwar “Settlement” in the Eastern D.R. Congo (2003–2006)
Authors: Autesserre Séverine 
Published: January 2007

Abstract:This article develops a conceptual analysis of the dynamics of violence during the transition from war to peace and democracy in the Democratic Republic of Congo between 2003 and 2006. I locate the sources, at the local, national, and regional levels, of continued local violence during this transition. Through an analysis of the situation in the Kivus, I illustrate how local dynamics interacted with the national and regional dimensions of the conflict. I demonstrate that, after a national and regional settlement was reached, some local conflicts over land and political power increasingly became self-sustaining and autonomous from the national and regional tracks.
Popular Culture and Public Space in Africa: The Possibilities of Cultural Citizenship
Authors: Dolby Nadine 
Published: January 2007

Abstract:Popular culture in Africa is increasingly intertwined with the public space of nations. Drawing on contemporary scholarship on popular culture, citizenship, and identity in transnational and global contexts, this article analyzes the phenomenal success of the television showBig Brother Africain 2003 and argues that people's everyday engagement with popular culture, including television, must be a central component of understanding emergent public spaces and citizenship practices in Africa's present and future.
Origen and Christian Naming: Textual Exhaustion and the Boundaries of Gentility in Commentary on John 1
Authors: Chin Catherine M. 
Published: January 2007

This article examines Origen's exegetical practice in the Commentary on JohnÂ 1 in the light of issues from Stoic linguistics and cosmology, particularly the problem of delineating complete meaning for any given word and the related problem of cosmic reunification with the divine logos. The technique of exegetical exhaustion, exemplified in Origen's list of divine names, is shown to be, along Stoic lines, a linguistic participation in the unification of the scriptural reader with the divine, to be completed only at the end of the Christian eschatological narrative. Since this exegetical technique emphasizes plenitude of meaning rather than correctness, however, it entails distinctions between readers that the categories of orthodoxy and heresy do not adequately convey.
Berechnung erdgedeckter Lagertanks nach Windels
Authors: Bußhaus Ludger 
Published: January 2007

AbstractErdgedeckte Lagertanks sind zylindrische Behälter, die auf einem Sandbett liegen und ein‐ oder doppelwandig ausgebildet sind. Sie dienen zur unter‐ oder oberirdischen Lagerung von Flüssigkeiten und weisen eine volle oder teilweise Erddeckung auf. Die unterirdische Lagerung erfolgt üblicherweise als “Grabenlagerung” im gewachsenen Boden, und die oberirdische Lagerung mit einer hügelförmigen Überschüttung wird als “Hünengrablagerung” bezeichnet. Bei beiden Lagerungsarten ist sowohl die Einzellagerung als auch eine Batterielagerung möglich.
Zugschwellverhalten von offenen Spiralseilen
Authors: Raupp Daniela , Vogel Wolfram , Wehking Karl‐Heinz 
Published: January 2007

AbstractFür Seile im Bauwesen werden unlösbare Seilendverbindungen, wie Vergüsse und Preßfittinge, eingesetzt. Die Preßfittinge zeichnen sich durch eine elegante Formgebung mit zahlreichen Anschlußmöglichkeiten aus. Seile werden im Bauwesen vorwiegend statisch, aber auch dynamisch zugschwellbeansprucht. Für offene Spiralseile (OSS) mit unterschiedlichen Endverbindungen liegen bereits vereinzelte Zugschwelluntersuchungen vor. Aufgrund uneinheitlicher Auswertungsmethoden können diese jedoch nicht ohne weiteres auf andere Seilkonstruktionen und Endverbindungen übertragen werden. Hinzu kommt, daß die zulässigen Schwingweiten nur für bestimmte Konstruktionen in Normen festgelegt sind. Bei den vermehrt eingesetzten Preßfittingen (auch Bolzenverpressungen genannt) ist zunächst unklar, wie groß die ertragbaren schwingenden Beanspruchungen (Mittellast und Schwingweite) in Abhängigkeit von Seil‐ und Bolzenwerkstoffen sowie Preßparametern sind.Einen großen Einfluß auf das Ermüdungsverhalten von Seilzuggliedern hat u. a. die Wahl der Seilendverbindungen. In diesem Aufsatz wird über die Ergebnisse des AiF‐Forschungsprojekts (Arbeitsgemeinschaft industrieller Forschungsvereinigungen “Otto von Guericke” e.V.) “Vergleich der Zugschwelleigenschaften von Bolzenverpressungen für Stahlseile mit unterschiedlichen Werkstoffen” berichtet.