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Particular Study (particular + study)
Selected AbstractsTransmission Electron Microscopy and UV,vis,IR Spectroscopy Analysis of the Diameter Sorting of Carbon Nanotubes by Gradient Density UltracentrifugationADVANCED FUNCTIONAL MATERIALS, Issue 14 2009Romain Fleurier Abstract Diameter separation of single-walled carbon nanotubes is achieved via the density gradient ultracentrifugation process. Statistical analysis of the separated samples is performed using high-resolution transmission electron microscopy (HRTEM). The evolution of the diameter distribution with respect to the gradient density is extracted by analyzing hundreds of HRTEM images, and the results are found to be consistent with those estimated by UV,vis,IR spectroscopy. The efficiency of the separation process can be quantitatively characterized by the standard deviation of the diameter distribution, which is determined from the TEM analyses. This particular study indicated that for electric arc nanotubes dispersed in sodium cholate, diameter sorting is more efficient in the upper part of the gradient. [source] Trends in aquatic macrophyte species turnover in Northern Ireland , which factors determine the spatial distribution of local species turnover?GLOBAL ECOLOGY, Issue 5 2004Einar Heegaard ABSTRACT Aim, The study examined qualitative predictions of ecological theories in relation to the spatial distribution of species turnover of aquatic macrophytes, through the following parameters: (1) distance between lakes (2) chemical conditions of the lakes (3) chemical differences between the lakes, and (4) the lake size. Location, 562 lakes dispersed throughout Northern Ireland were analysed. Methods, To obtain species turnover estimates independent of richness, the average distance between focal lakes and their five nearest neighbours in ordination space (DCA) was standardized by the species richness in a Generalized Additive Model (GAM). The relationships between species turnover and ecological (chemical condition, chemical difference, distance between lakes, and lake-size) and geographical parameters (latitude, longitude, and altitude) were analysed using GAM. Results, The results indicate that the pattern in species turnover is a combination of the chemical conditions and the distance between the lakes, including the interaction term. The effects of chemical heterogeneity and lake size parameters were both positive but weak. In general, increased distance and decreased ionic concentration contribute to increased turnover. The influence of distance on species turnover is strongest at low and high altitude, and at mid-elevation the species turnover is mainly driven by the chemical conditions. Towards the north there is an increasing influence of distance, whereas in the south the chemical conditions have their strongest influence. Conclusions, There is a need for components from several established ecological theories to explain the spatial trends in species turnover within Northern Ireland. Central theories in this particular study are the population/metapopulation dynamics, the continuum concept, and the species-pool concept. [source] Generalizability in Communication ResearchHUMAN COMMUNICATION RESEARCH, Issue 4 2002Michael A. Shapiro In communication research, attempts to enhance external validity usually focus on techniques to enhance the surface representativeness attained in a particular study. Such surface representativeness is a useful tool. However, a larger ability to generalize emerges from a constantly evolving scientific discourse across multiple studies about how social meanings and social behaviors impact outcomes. The resulting conceptual knowledge enables us to generalize about communication across a much wider range of persons, settings, times, and messages than does surface similarity. The findings of a study should be examined in light of its contribution to theory. The surface representativeness of a study is usually not a good indicator of contribution to theory. The discipline of communication, particularly journal editors and reviewers, bears a heavy responsibility to think about generalizability in the complex ways the topic requires. [source] A 10 year cloud climatology over Scandinavia derived from NOAA Advanced Very High Resolution Radiometer imageryINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 9 2003Karl-Göran Karlsson Abstract Results from a satellite-based method to compile regional cloud climatologies covering the Scandinavian region are presented. Systematic processing of multispectral image data from the NOAA Advanced Very High Resolution Radiometer (AVHRR) instrument has been utilized to provide monthly cloud climatologies covering the period 1991,2000. Considerable local-scale variation of cloud amounts was found in the region. The inland Baltic Sea and adjacent land areas exhibited a large-amplitude annual cycle in cloudiness (high cloud amounts in winter, low cloud amounts in summer) whereas a weak-amplitude reversed annual cycle (high cloud amounts with a weak maximum in summer) was found for the Scandinavian mountain range. As a contrast, conditions over the Norwegian Sea showed high and almost unchanged cloud amounts during the course of the year. Some interesting exceptions to these patterns were also seen locally. The quality of the satellite-derived cloud climatology was examined through comparisons with climatologies derived from surface cloud observations, from the International Satellite Cloud Climatology Project (ISCCP) and from the European Centre for Medium-range Weather Forecasts ERA-40 data set. In general, cloud amount deviations from surface observations were smaller than 10% except for some individual winter months, when the separability between clouds and snow-covered cold land surfaces is often poor. The ISCCP data set showed a weaker annual cycle in cloudiness, generally caused by higher summer-time cloud amounts in the region. Very good agreement was found with the ERA-40 data set, especially for the summer season. However, ERA-40 showed higher cloud amounts than SCANDIA and ISCCP during the winter season. The derived cloud climatology is affected by errors due to temporal AVHRR sensor degradation, but they appear to be small for this particular study. The data set is proposed as a valuable data set for validation of cloud description in numerical weather prediction and regional climate simulation models. Copyright © 2003 Royal Meteorological Society [source] Nursing and midwifery management of hypoglycaemia in healthy term neonatesINTERNATIONAL JOURNAL OF EVIDENCE BASED HEALTHCARE, Issue 7 2005Vivien Hewitt BSc(Hons) GradDipLib Executive summary Objectives The primary objective of this review was to determine the best available evidence for maintenance of euglycaemia, in healthy term neonates, and the management of asymptomatic hypoglycaemia in otherwise healthy term neonates. Inclusion criteria Types of studies The review included any relevant published or unpublished studies undertaken between 1995 and 2004. Studies that focus on the diagnostic accuracy of point-of-care devices for blood glucose screening and/or monitoring in the neonate were initially included as a subgroup of this review. However, the technical nature and complexity of the statistical information published in diagnostic studies retrieved during the literature search stage, as well as the considerable volume of published research in this area, suggested that it would be more feasible to analyse diagnostic studies in a separate systematic review. Types of participants The review focused on studies that included healthy term (37- to 42-week gestation) appropriate size for gestational age neonates in the first 72 h after birth. Exclusions ,,preterm or small for gestational age newborns; ,,term neonates with a diagnosed medical or surgical condition, congenital or otherwise; ,,babies of diabetic mothers; ,,neonates with symptomatic hypoglycaemia; ,,large for gestational age neonates (as significant proportion are of diabetic mothers). Types of intervention All interventions that fell within the scope of practice of a midwife/nurse were included: ,,type (breast or breast milk substitutes), amount and/or timing of feeds, for example, initiation of feeding, and frequency; ,,regulation of body temperature; ,,monitoring (including screening) of neonates, including blood or plasma glucose levels and signs and symptoms of hypoglycaemia. Interventions that required initiation by a medical practitioner were excluded from the review. Types of outcome measures Outcomes that were of interest included: ,,occurrence of hypoglycaemia; ,,re-establishment and maintenance of blood or plasma glucose levels at or above set threshold (as defined by the particular study); ,,successful breast-feeding; ,,developmental outcomes. Types of research designs The review initially focused on randomised controlled trials reported from 1995 to 2004. Insufficient randomised controlled trials were identified and the review was expanded to include additional cohort and cross-sectional studies for possible inclusion in a narrative summary. Search strategy The major electronic databases, including MEDLINE/PubMed, CINAHL, EMBASE, LILACS, Cochrane Library, etc., were searched using accepted search techniques to identify relevant published and unpublished studies undertaken between 1995 and 2004. Efforts were made to locate any relevant unpublished materials, such as conference papers, research reports and dissertations. Printed journals were hand-searched and reference lists checked for potentially useful research. The year 1995 was selected as the starting point in order to identify any research that had not been included in the World Health Organisation review, which covered literature published up to 1996. The search was not limited to English language studies. Assessment of quality Three primary reviewers conducted the review assisted by a review panel. The review panel was comprised of nine nurses with expertise in neonatal care drawn from senior staff in several metropolitan neonatal units and education programs. Authorship of journal articles was not concealed from the reviewers. Methodological quality of each study that met the inclusion criteria was assessed by two reviewers, using a quality assessment checklist developed for the review. Disagreements between reviewers were resolved through discussion or with the assistance of a third reviewer. Data extraction and analysis Two reviewers used a data extraction form to independently extract data relating to the study design, setting and participants; study focus and intervention(s); and measurements and outcomes. As only one relevant randomised controlled trial was found, a meta-analysis could not be conducted nor tables constructed to illustrate comparisons between studies. Instead, the findings were summarised by a narrative identifying any relevant findings that emerged from the data. Results Seven studies met the inclusion criteria for the objective of this systematic review. The review provided information on the effectiveness of three categories of intervention , type of feeds, timing of feeds and thermoregulation on two of the outcome measures identified in the review protocol , prevention of hypoglycaemia, and re-establishment and maintenance of blood or plasma glucose levels above the set threshold (as determined by the particular study). There was no evidence available on which to base conclusions for effectiveness of monitoring or developmental outcomes, and insufficient evidence for breast-feeding success. Given that only a narrative review was possible, the findings of this review should be interpreted with caution. The findings suggest that the incidence of hypoglycaemia in healthy, breast-fed term infants of appropriate size for gestational age is uncommon and routine screening of these infants is not indicated. The method and timing of early feeding has little or no influence on the neonatal blood glucose measurement at 1 h in normal term babies. In healthy, breast-fed term infants the initiation and timing of feeds in the first 6 h of life has no significant influence on plasma glucose levels. The colostrum of primiparous mothers provides sufficient nutrition for the infant in the first 24 h after birth, and supplemental feeds or extra water is unnecessary. Skin-to-skin contact appears to provide an optimal environment for fetal to neonatal adaptation after birth and can help to maintain body temperature and adequate blood glucose levels in healthy term newborn infants, as well as providing an ideal opportunity to establish early bonding behaviours. Implications for practice The seven studies analysed in this review confirm the World Health Organisation's first three recommendations for prevention and management of asymptomatic hypoglycaemia, namely: 1Early and exclusive breast-feeding is safe to meet the nutritional needs of healthy term newborns worldwide. 2Healthy term newborns that are breast-fed on demand need not have their blood glucose routinely checked and need no supplementary foods or fluids. 3Healthy term newborns do not develop ,symptomatic' hypoglycaemia as a result of simple underfeeding. If an infant develops signs suggesting hypoglycaemia, look for an underlying condition. Detection and treatment of the cause are as important as correction of the blood glucose level. If there are any concerns that the newborn infant might be hypoglycaemic it should be given another feed. Given the importance of thermoregulation, skin-to-skin contact should be promoted and ,kangaroo care' encouraged in the first 24 h after birth. While it is important to main the infant's body temperature care should be taken to ensure that the child does not become overheated. [source] Eldercare and job productivity: An accommodation analysisJOURNAL OF LEADERSHIP STUDIES, Issue 4 2008Kenneth C. Sherman Over the next decade, the number of working adults relegated to the role of caregiver for one or more elderly family members will rapidly surge. The emotional, physical, and financial stress of caregiving has already begun to impact the productivity of the employee elder caregiver in the workplace, with estimates placing the annual costs around $30 billion. We can expect costs to grow as workers and their elderly parents continue to age. This particular study addresses the fundamental research question of what affects the job performance of employee elder caregivers. The results support the conclusion that the relationship among caregiving, personal support, organizational accommodation, and job productivity is multidimensional. Organizations attuned to the demands of elder caregiving can work with affected employees to reduce or eliminate declines in job productivity. Future researchers and practitioners can reconsider their research protocols and interventions along a wide continuum of interactions in the employee's home and workplace environments. [source] Sampling methods for phlebotomine sandfliesMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2 2000B. Alexander Summary A review is presented of methods for sampling phlebotomine sandflies (Diptera: Psychodidae). Among ,500 species of Phlebotominae so far described, mostly in the New World genus Lutzomyia and the Old World genus Phlebotomus, about 10% are known vectors of Leishmania parasites or other pathogens. Despite being small and fragile, sandflies have a wide geographical range with species occupying a considerable diversity of ecotopes and habitats, from deserts to humid forests, so that suitable methods for collecting them are influenced by environmental conditions where they are sought. Because immature phlebotomines occupy obscure terrestrial habitats, it is difficult to find their breeding sites. Therefore, most trapping methods and sampling procedures focus on sandfly adults, whether resting or active. The diurnal resting sites of adult sandflies include tree holes, buttress roots, rock crevices, houses, animal shelters and burrows, from which they may be aspirated directly or trapped after being disturbed. Sandflies can be collected during their periods of activity by interception traps, or by using attractants such as bait animals, CO2 or light. The method of trapping used should: (a) be suited to the habitat and area to be surveyed, (b) take into account the segment of the sandfly population to be sampled (species, sex and reproduction condition) and (c) yield specimens of appropriate condition for the study objectives (e.g. identification of species present, population genetics or vector implication). Methods for preservation and transportation of sandflies to the laboratory also depend on the objectives of a particular study and are described accordingly. [source] Pitfalls in non-therapeutic research in childrenPEDIATRIC PULMONOLOGY, Issue 11 2006George B. Mallory Jr. Research has brought significant medical advances in modern times benefiting virtually all people. Children as a class should not be excluded from research studies. However, non-therapeutic research is potentially problematic in children because they must be afforded special protection from harm and exploitation by care-givers, researchers, and institutional review boards. An article in this month's journal provides an opportunity for a systematic analysis using the methodology provided by the United States Code of Federal Regulations. The research design of this particular study does not appear to stand up to the requirements of the Code. Pediatr Pulmonol. 2006, 41:1014,1016. © 2006 Wiley-Liss, Inc. [source] Redefining Affective Disorders: Relevance for Drug DevelopmentCNS: NEUROSCIENCE AND THERAPEUTICS, Issue 1 2008Steven D Targum The evaluation of new drug entities with specific modes of action may be hampered by rigid diagnostic classification systems and patient selection processes that do not focus on the anticipated symptomatic, behavioral, and functional outcomes to be achieved. Patients enrolled in central nervous system (CNS) clinical trials may present with a heterogeneous group of symptoms representing several syndromes or subtypes, subsumed under the same diagnosis in the DSM-IV classification system. As a result, enrolled patients may not have the valid illness characteristics of interest to the particular study. We propose that clinical drug development needs to focus on the primary nosological entity likely to be affected by a new drug entity's mode of action. Ideally, a valid patient will have the acute primary symptoms that the novel drug is supposed to influence. In this article, we propose operational criteria to delineate a more symptom-specific and ecologically valid approach to the identification of the valid patient for clinical trials. [source] | |||||||||||||