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Evolving Concept (evolving + concept)
Selected AbstractsTHE ,LITTLE ICE AGE': RE-EVALUATION OF AN EVOLVING CONCEPTGEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 1 2005JOHN A. MATTHEWS ABSTRACT. This review focuses on the development of the ,Little Ice Age' as a glaciological and climatic concept, and evaluates its current usefulness in the light of new data on the glacier and climatic variations of the last millennium and of the Holocene. ,Little Ice Age' glacierization occurred over about 650 years and can be defined most precisely in the European Alps (c. AD 1300,1950) when extended glaciers were larger than before or since. ,Little Ice Age' climate is defined as a shorter time interval of about 330 years (c. AD 1570,1900) when Northern Hemisphere summer temperatures (land areas north of 20°N) fell significantly below the AD 1961,1990 mean. This climatic definition overlaps the times when the Alpine glaciers attained their latest two highstands (AD 1650 and 1850). It is emphasized, however, that ,Little Ice Age' glacierization was highly dependent on winter precipitation and that ,Little Ice Age' climate was not simply a matter of summer temperatures. Both the glacier-centred and the climate-centred concepts necessarily encompass considerable spatial and temporal variability, which are investigated using maps of mean summer temperature variations over the Northern Hemisphere at 30-year intervals from AD 1571 to 1900. ,Little Ice Age'-type events occurred earlier in the Holocene as exemplified by at least seven glacier expansion episodes that have been identified in southern Norway. Such events provide a broader context and renewed relevance for the ,Little Ice Age', which may be viewed as a ,modern analogue' for the earlier events; and the likelihood that similar events will occur in the future has implications for climatic change in the twenty-first century. It is concluded that the concept of a ,Little Ice Age' will remain useful only by (1) continuing to incorporate the temporal and spatial complexities of glacier and climatic variations as they become better known, and (2) by reflecting improved understanding of the Earth-atmosphere-ocean system and its forcing factors through the interaction of palaeoclimatic reconstruction with climate modelling. [source] Summary report of a national conference: Evolving concepts in liver allocation in the MELD and PELD eraLIVER TRANSPLANTATION, Issue S10 2004Kim M. Olthoff A national conference was held to review and assess data gathered since implementation of MELD and PELD and determine future directions. The objectives of the conference were to review the current system of liver allocation with a critical analysis of its strengths and weaknesses. Conference participants used an evidence-based approach to consider whether predicted outcome after transplantation should influence allocation, to discuss the concept of minimal listing score, to revisit current and potential expansion of exception criteria, and to determine whether specific scores should be used for automatic removal of patients on the waiting list. After review of data from the first 18 months since implementation, association and society leaders, and surgeons and hepatologists with wide regional representation were invited to participate in small group discussions focusing on each of the main objectives. At the completion of the meeting, there was agreement that MELD has had a successful initial implementation, meeting the goal of providing a system of allocation that emphasizes the urgency of the candidate while diminishing the reliance on waiting time, and that it has proven to be a powerful tool for auditing the liver allocation system. It was also agreed that the data regarding the accuracy of PELD as a predictor of pretransplant mortality were less conclusive and that PELD should be considered in isolation. Recommendations for the transplant community, based on the analysis of the MELD data, were discussed and are presented in the summary document. (Liver Transpl 2004;10:A6,A22.) [source] Evolving concepts in pathogenesis and treatment of ANCA-associated systemic vasculitidesNEPHROLOGY, Issue 1 2009CEES GM KALLENBERG [source] Evolving concepts of management of febrile neutropenia in children with cancerPEDIATRIC BLOOD & CANCER, Issue 2 2002Elmar Orudjev MD Abstract Background Recent investigations of febrile neutropenia in pediatric cancer patients have identified subsets of low-risk patients who can be managed with less antibiotic therapy than previously recommended standards. Methods and Materials PubMed and Medline were searched for prospective trials and reviews of febrile neutropenia in children. Magnitude and duration of fever and neutropenia, comorbidities, and therapeutic strategies were examined. Results Twenty-seven prospective trials and five reviews were identified. The child with cancer and low-risk febrile neutropenia is clinically well and afebrile within 24,96 hr of antibiotic therapy and has evidence of marrow recovery with a rising phagocyte count. Disqualifying comorbidities include leukemia at diagnosis or in relapse, uncontrolled cancer, age under 1 year, medical condition(s) that would otherwise require hospitalization and social or economic conditions that may potentially compromise access to care or compliance. Therapeutic strategies include parenteral or oral antibiotics in the hospital with early discharge or parenteral antibiotics in the outpatient setting followed by oral or parenteral therapy and daily reassessment. Although as many as 25% of low-risk patients require modification of therapy and/or hospitalization, life-threatening or fatal infection is exceptional. Conclusion One-third to one-half the children with febrile neutropenia are at low-risk of serious infection. In the context of clinic trials, they can be safely managed with inpatient or outpatient strategies that maintain close follow-up and reduce the burden of antibiotic therapy. Adoption of these alternative strategies as the standard of care should proceed with caution guided by written protocols. Med Pediatr Oncol 2002;39:77,85. © 2002 Wiley-Liss, Inc. [source] The concept of the epilepsy syndrome: How useful is it in clinical practice?EPILEPSIA, Issue 2009Ettore Beghi Summary An epilepsy syndrome is a disorder characterized by a cluster of symptoms and signs customarily occurring in combination. A syndromic approach to the epilepsies would be of practical value for diagnostic, prognostic, and therapeutic purposes. However, despite considerable efforts by leaders in the field of epileptology and the improved knowledge of the clinical, genetic, imaging, and biologic aspects of epilepsy, there are no measurable objective criteria for recognizing seizure types and epilepsy syndromes as separate diagnostic entities with well-defined prognostic and therapeutic aspects. The lack of pragmatic, evidence-based instruments to devise a syndromic classification useful for clinical practice can be explained by the evolving concept of epilepsy syndrome, its dynamic characteristics, the poor prognostic predictivity, and the extremely complex genetic and pathophysiologic mechanisms underlying the epileptic phenomena. In addition, the results of the published reports on epilepsy syndromes are mostly biased by flaws in the study population, design, and statistical analysis. The Classification Core Group of the International League Against Epilepsy (ILAE), which is working on a new classification of the epilepsies, stated that the process of syndrome identification requires that an evidence-based approach be applied to the published literature and future studies. [source] Symptom burden in inflammatory bowel disease: Rethinking conceptual and theoretical underpinningsINTERNATIONAL JOURNAL OF NURSING PRACTICE, Issue 5 2010Dawn Farrell BSC RGN Farrell D, Savage E. International Journal of Nursing Practice 2010; 16: 437,442 Symptom burden in inflammatory bowel disease: Rethinking conceptual and theoretical underpinnings Symptom control is fundamental to the nursing management of inflammatory bowel disease (IBD). However, symptom control can be problematic for individuals with IBD, which could result in symptom burden. Symptom burden is an evolving concept in the discipline of nursing and to date little is known about how the defining characteristics of this concept have been applied to symptom research in IBD. In this discussion paper, the concept of symptom burden and the theory of unpleasant symptoms are explored as a basis for understanding symptom research in IBD. This is followed by a critical examination of previous symptom research in IBD. Our conclusion is that there is a need to rethink conceptual and theoretical underpinnings of symptom burden when researching IBD to take account of its defining characteristics, namely symptom severity, frequency and duration, quality and distress. Research knowledge on these defining characteristics will be important to inform nursing assessment of symptom burden in clinical practice. [source] To be, or not to be, a non-native freshwater fish?JOURNAL OF APPLIED ICHTHYOLOGY, Issue 4 2005G. H. Copp Summary We examine the evolving concept of what constitutes a non-native (or alien) freshwater fish. In an attempt to distinguish between biogeographical and socio-political perspectives, we review the patterns in the introduction and dispersal of non-native fishes in Europe and North America, and especially the recent expansion of Ponto-Caspian gobies in Europe. We assess patterns in the development of national policy and legislation in response to the perceived threat of non-native fish introductions to native species and ecosystems. We review, and provide a glossary of, the terms and definitions associated with non-native species. Finally, we discuss perspectives as regards the future treatment of naturalized species. [source] An introduction to Decentralized Cooperation: definitions, origins and conceptual mappingPUBLIC ADMINISTRATION & DEVELOPMENT, Issue 4 2003Pierre HafteckArticle first published online: 28 JUL 200 The term ,Decentralized Cooperation', coined in the 1980s, is interpreted differently by various organisations involved in development cooperation. However, there are points of convergence among these interpretations that suggest a common definition involving: (a) the lead actors (local governments), (b) an overarching objective (sustainable local development) and (c) the nature of activities carried out (exchanges and support). From a historical perspective, the origin of Decentralized Cooperation is two-fold. On the development cooperation scene, the concept emerged when the array of actors involved in development projects widened as a result of major changes in aid themes and approaches. In the field of international relations between local governments, Decentralized Cooperation activities appeared as the scope of municipal twinnings also widened accordingly to involve partners from countries in development or in transition. Today, Decentralized Cooperation continues as an evolving concept located at the intersection of its two parent fields: development cooperation and international municipal relations. At this intersection, a fusion of experiences, resources and ideas is taking place. Copyright © 2003 John Wiley & Sons, Ltd. [source] Ecological gradients, subdivisions and terminology of north-west European miresJOURNAL OF ECOLOGY, Issue 2 2000B. D. Wheeler Summary 1,The historical development of mire ecology and terminology is reviewed in relation to evolving concepts and perceptions, and the diverse schools and traditions of vegetation and habitat description and research. 2,Most ecological and floristic variation within north-west European mire vegetation is accounted for by three ecological gradients: the acid base-poor vs. neutral, base- and bicarbonate-rich gradient; the gradient in fertility related to availability of the limiting nutrient elements N and P; and the water level gradient. Effects of salinity and the spring,flush,fen gradients are of more local significance, usually easily recognized. Land use is an important additional factor. 3,The mineral-soil-water limit between ombrotrophic and minerotrophically influenced sites is not sharp, and cannot be related to consistent differences in either vegetation or water chemistry. It should be abandoned as a general main division within mires. 4,The most important natural division is between ,bog', with pH generally < 5.0, low Ca2+, and Cl, and SO42, as the main inorganic anions, typically dominated by sphagna, ericoids and calcifuge Cyperaceae, and ,fen', with pH generally > 6.0, high Ca2+ and HCO3,, vegetation rich in dicotyledonous herbs and ,brown mosses'. This division is reflected in a bimodal distribution of pH. 5,The terms oligotrophic, mesotrophic and eutrophic should refer only to nutrient richness (fertility, mainly N and P), not to base richness (metallic cations and pH). 6,It is recommended that ,mire' should embrace both wetlands on peat and related communities on mineral soils, that ,bog' (unqualified) should encompass both ombrotrophic and weakly minerotrophic mires, including ,bog woodland', and that ,fen' should be restricted to base-rich mires but include both herbaceous and wooded vegetation (,fen carr'). 7,Definitions are given for a range of broadly defined categories that should cover most vegetation types commonly encountered. The relation of these to British national vegetation classification types and to major units in European phytosociology is outlined. [source] | |||||||||||||