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Methodological Aspects (methodological + aspect)
Selected AbstractsPrescription Duration After Drug Copay Changes in Older People: Methodological AspectsJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 3 2002Sebastian Schneeweiss MD OBJECTIVES: Impact assessment of drug benefits policies is a growing field of research that is increasingly relevant to healthcare planning for older people. Some cost-containment policies are thought to increase noncompliance. This paper examines mechanisms that can produce spurious reductions in drug utilization measures after drug policy changes when relying on pharmacy dispensing data. Reference pricing, a copayment for expensive medications above a fixed limit, for angiotensin-converting enzyme (ACE) inhibitors in older British Columbia residents, is used as a case example. DESIGN: Time series of 36 months of individual claims data. Longitudinal data analysis, adjusting for autoregressive data. SETTING: Pharmacare, the drug benefits program covering all patients aged 65 and older in the province of British Columbia, Canada. PARTICIPANTS: All noninstitutionalized Pharmacare beneficiaries aged 65 and older who used ACE inhibitors between 1995 and 1997 (N = 119,074). INTERVENTION: The introduction of reference drug pricing for ACE inhibitors for patients aged 65 and older. MEASUREMENTS: Timing and quantity of drug use from a claims database. RESULTS: We observed a transitional sharp decline of 11%± a standard error of 3% (P = .02) in the overall utilization rate of all ACE inhibitors after the policy implementation; five months later, utilization rates had increased, but remained under the predicted prepolicy trend. Coinciding with the sharp decrease, we observed a reduction in prescription duration by 31% in patients switching to no-cost drugs. This reduction may be attributed to increased monitoring for intolerance or treatment failure in switchers, which in turn led to a spurious reduction in total drug utilization. We ruled out the extension of medication use over the prescribed duration through reduced daily doses (prescription stretching) by a quantity-adjusted analysis of prescription duration. CONCLUSION: The analysis of prescription duration after drug policy interventions may provide alternative explanations to apparent short-term reductions in drug utilization and adds important insights to time trend analyses of drug utilization data in the evaluation of drug benefit policy changes. J Am Geriatr Soc 50:521,525, 2002. [source] Passive seismic imaging with directive ambient noise: application to surface waves and the San Andreas Fault in Parkfield, CAGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2009Philippe Roux SUMMARY This study deals with surface waves extracted from microseismic noise in the (0.1,0.2 Hz) frequency band with passive seismic-correlation techniques. For directive noise, we explore the concept of passive seismic-noise tomography performed on three-component sensors from a dense seismic network. From the nine-component correlation tensor, a rotation algorithm is introduced that forces each station pair to re-align in the noise direction, a necessary condition to extract unbiased traveltime from passive seismic processing. After rotation is performed, the new correlation tensor exhibits a surface wave tensor from which Rayleigh and Love waves can be separately extracted for tomography inversion. Methodological aspects are presented and illustrated with group-speed maps for Rayleigh and Love waves and ellipticity measurements made on the San Andreas Fault in the Parkfield area, California, USA. [source] Methods for evaluating human impact on soil microorganisms based on their activity, biomass, and diversity in agricultural soilsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 3 2006Rainer Georg Joergensen Abstract The present review is focused on microbiological methods used in agricultural soils accustomed to human disturbance. Recent developments in soil biology are analyzed with the aim of highlighting gaps in knowledge, unsolved research questions, and controversial results. Activity rates (basal respiration, N mineralization) and biomass are used as overall indices for assessing microbial functions in soil and can be supplemented by biomass ratios (C : N, C : P, and C : S) and eco-physiological ratios (soil organic C : microbial-biomass C, qCO2, qNmin). The community structure can be characterized by functional groups of the soil microbial biomass such as fungi and bacteria, Gram-negative and Gram-positive bacteria, or by biotic diversity. Methodological aspects of soil microbial indices are assessed, such as sampling, pretreatment of samples, and conversion factors of data into biomass values. Microbial-biomass C (µg (g soil),1) can be estimated by multiplying total PLFA (nmol (g soil),1) by the FPLFA -factor of 5.8 and DNA (µg (g soil),1) by the FDNA -factor of 6.0. In addition, the turnover of the soil microbial biomass is appreciated as a key process for maintaining nutrient cycles in soil. Examples are briefly presented that show the direction of human impact on soil microorganisms by the methods evaluated. These examples are taken from research on organic farming, reduced tillage, de-intensification of land-use management, degradation of peatland, slurry application, salinization, heavy-metal contamination, lignite deposition, pesticide application, antibiotics, TNT, and genetically modified plants. [source] Methodological aspects of 3D and automated 2D analyses of white matter neuronal density in temporal lobe epilepsyNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 3 2006S. H. Eriksson White matter neuronal density has been correlated with clinical outcome after temporal lobectomy for refractory epilepsy. Both morphometric 2D (two-dimensional) and stereological 3D (three-dimensional) analyses of neuronal density have been performed. 3D analyses are thought to be more accurate than 2D counts, but more time-consuming. We compared 3D and automated 2D measurements in the same specimens. Adjacent 20-µm (for 3D analyses) and 5-µm (for 2D analyses) sections from 10 temporal lobectomies were stained for NeuN immunohistochemistry. Analysis of 100% of a region of interest (ROI) in deep white matter was performed using an image analysis system (Histometrix, Kinetic Imaging, UK). 3D analyses were undertaken using ×,63 magnification (6 h/case). Automated 2D analyses were undertaken using automatic neuronal identification at ×,10 magnification with three to four repeats (1.5 h/case). The range of neuronal densities for 3D measurements was 2120,4910 neurones/mm3, and for automated 2D measurements 17.4,47.1 neurones/mm2. There was a linear correlation between the two methods with an r2 of 0.58. The limits of agreement for the two methods were 1718 to ,2234 neurones/mm3. Count,recount variability was 1.4,9.9% for the 3D and 5.1,36.6% for the automated 2D measurements. We found a wide range of white matter neuronal densities using either analysis. The low agreement between methods, and the high count,recount variability for the automated 2D analyses, indicate that despite being more time-consuming, rigorous 3D stereological analyses have to be performed to obtain reliable results. These findings have implications for studies requiring neuronal counts in normal and disease states. [source] Methodological aspects of rigor in qualitative nursing research on families involved in intensive care units: A literature reviewNURSING & HEALTH SCIENCES, Issue 1 2007Sevald Hųye rn, mnsc Abstract, Rigor has important ramifications for the entire qualitative research process. The aim of this study was to evaluate aspects of methodological congruence by focusing on four dimensions of rigor in qualitative nursing research related to the presence of patients' family members in the intensive care unit. Eight research papers covering the years 1990,2004 were analyzed by means of one of Burns and Grove's standards, methodological congruence, for critique and consistency. The results show that there are varying degrees of focus on procedural rigor, such as limitations and bias. Ethical rigor is described clearly in some papers, while others lack descriptions of confidentiality and the voluntary nature of participation. However, all papers contain descriptions of qualitative data analysis. In conclusion, there were strengths in procedural rigor and auditability, but also some limitations in the identification of theoretical development and the scientific tradition on which the article is based. [source] Methodological aspects of epidemiological studies of periodontal diseasesPERIODONTOLOGY 2000, Issue 1 2002Albert Kingman First page of article [source] Methodological aspects of in vitro sensing of L -glutamate in acute brain slicesTHE CHEMICAL RECORD, Issue 6 2007Masao Sugawara Abstract L -Glutamate is a major amino acid neurotransmitter in the central neuronal system of the mammalian brain and plays a vital role in brain development, synaptic plasticity, neurotoxicity, and neuropathological disorders. Despite technical limitations, progress is being made in sensing L -glutamate in vivo and in vitro. Sophisticated microsensors with the necessary spatial and temporal resolution have recently been emerging, which enable us to discern regional distribution, concentration levels, and temporal changes of L -glutamate in acute brain slices. The L -glutamate sensors for in vitro sensing have different structures and sizes, such as glass capillary-based enzyme sensors, polymer-coated enzyme sensors, and patch sensors based on natural sensing probes. The concentration of L -glutamate released in brain slices by chemical stimulation is markedly dependent on neuronal regions, types of stimulation, and sensing methods. Real- and long-time monitoring of L -glutamate in acute hippocampal slices is beginning to shed light on L -glutamate release related to the molecular mechanisms of long-term potentiation. Progress is also being made toward the visualization of L -glutamate release in acute hippocampal slices. The methodological aspects of in vitro sensing of L -glutamate are discussed. © 2007 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 7: 317,325; 2007: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20126 [source] Analysis of errors in the structure determination of MsbAACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2009Philip D. Jeffrey The determination of incorrect structures for the ABC transporter MsbA gave rise to questions of how this could have occurred. Methodological aspects of the MsbA structure determination are explored in light of this error. [source] ON SOCIAL LEARNING AND ROBUST EVOLUTIONARY ALGORITHM DESIGN IN THE COURNOT OLIGOPOLY GAMECOMPUTATIONAL INTELLIGENCE, Issue 2 2007Floortje Alkemade Agent-based computational economics (ACE) combines elements from economics and computer science. In this article, the focus is on the relation between the evolutionary technique that is used and the economic problem that is modeled. In the field of ACE, economic simulations often derive parameter settings for the genetic algorithm directly from the values of the economic model parameters. This article compares two important approaches that are dominating in ACE and shows that the above practice may hinder the performance of the genetic algorithm and thereby hinder agent learning. More specifically, it is shown that economic model parameters and evolutionary algorithm parameters should be treated separately by comparing the two widely used approaches to social learning with respect to their convergence properties and robustness. This leads to new considerations for the methodological aspects of evolutionary algorithm design within the field of ACE. [source] Cover Picture: Electrophoresis 9'2010ELECTROPHORESIS, Issue 9 2010Article first published online: 26 APR 2010 Issue no. 9 is a special issue on "CEC and EKC" comprising one "Fast Track" article and 21 articles distributed over two distinct parts. "Part I groups 13 contributions on enantioseparations in CE, CEC and capillary LC using various chiral selectors and their applications to a wide range of chiral species, while Part II assembles 8 papers on various methodological aspects and applications of EKC, CEC and CE". The "Fast Track" paper describes enhanced selectivity in CZE with multi-chiral selector systems. [source] Recent advances in capillary electrophoresis and capillary electrochromatography of peptidesELECTROPHORESIS, Issue 22-23 2003Vįclav Ka Abstract An overview of the recent developments in the applications of high-performance capillary electromigration methods, namely zone electrophoresis, isotachophoresis, isoelectric focusing, affinity electrophoresis, electrokinetic chromatography, and electrochromatography, to analysis, preparation, and physicochemical characterization of peptides is presented. New approaches to the theoretical description and experimental verification of the electromigration behavior of peptides and the methodological aspects of capillary electroseparations of peptides, such as rational selection of separation conditions, sample treatment, and suppression of adsorption, are discussed, and new developments in individual separation modes and new designs of detection systems applied to peptide separations are shown. Several types of applications of capillary electromigration methods to peptide analysis are presented: quality control and purity tests, determination in biomatrices, monitoring of physical and chemical changes and enzymatic conversions, amino acid and sequence analysis, and peptide mapping. The examples of micropreparative peptide separations are given and capabilities of capillary electromigration techniques to provide important physicochemical characteristics of peptides are demonstrated. [source] Testing the group polarization hypothesis by using logit modelsEUROPEAN JOURNAL OF SOCIAL PSYCHOLOGY, Issue 1 2002Marķa F. Rodrigo This paper focuses on methodological aspects of group polarization research and has two well-defined parts. The first part presents a methodological overview of group polarization research together with an examination of the inadequacy, under certain circumstances, of the traditional parametric approach usually used to test this phenomenon based on pre-test/post-test means comparison across groups. It is shown that this approach will produce masks effects when groups are heterogeneous with regard to the observed change from pre-test to post-test. The second part suggests an alternative methodological approach based on logit models for the analysis of contingency tables from a categorization of the variable ,kind of shift'. This approach is illustrated and compared with the parametric approach with a simulated data set. Copyright © 2002 John Wiley & Sons, Ltd. [source] Nitrification in the Schelde estuary: methodological aspects and factors influencing its activityFEMS MICROBIOLOGY ECOLOGY, Issue 1 2002Monique J.M. de Bie Abstract We present a 15-month dataset on nitrification measurements in the Schelde estuary (Belgium and The Netherlands). Nitrification was estimated using the N-serve sensitive dark 14C-bicarbonate incorporation technique. A peak of nitrification activity was observed in the freshwater part of the estuary. Downstream from this peak, nitrification declined, probably because of ammonium limitation. A range of nitrification inhibitors was tested on both a Nitrosomonas europaea culture and estuarine samples. It was found that methyl fluoride and acetylene stimulated dark 14C-bicarbonate incorporation and those inhibitors were therefore considered inappropriate nitrification inhibitors in combination with this technique. The effect of the inhibitor N-serve was studied on the dark incorporation of 13C-bicarbonate into polar lipid derived fatty acids to further identify the dominant chemoautotrophic processes. Inhibition of polar lipid derived fatty acid labelling in the presence of N-serve was complete, suggesting that nitrifying bacteria dominated the chemoautotrophic community. [source] Research Techniques and Their Use in Managing Non,profit Organisations , An Illustration of DEA Analysis in NPO EnvironmentsFINANCIAL ACCOUNTABILITY & MANAGEMENT, Issue 3 2003Jarmo Vakkuri This article examines nonprofit organisations from the managerial viewpoint. The objective is to study the applicability of efficiency information in managing NPOs. For this purpose important conceptual and methodological aspects are addressed. An efficiency measurement technique (DEA) is then analysed as a case in point, and its main characteristics critically reviewed. DEA applications in four NPO environments are examined. The aim is to pinpoint possibilities and limitations in using DEA,based efficiency information in the management process of NPOs. The article argues in favour of a more profound comprehension of the use of efficiency information and the application of research techniques. [source] Mitotic counting in surgical pathology: sampling bias, heterogeneity and statistical uncertaintyHISTOPATHOLOGY, Issue 1 2001F B J M Thunnissen Mitotic counting in surgical pathology: sampling bias, heterogeneity and statistical uncertainty Although several articles on the methodological aspects of mitotic counting have been published, the effects of macroscopic sampling and tumour heterogeneity have not been discussed in any detail. In this review the essential elements for a standardized mitotic counting protocol are described, including microscopic calibration, specific morphological criteria, macroscopic selection, counting procedure, effect of biological variation, threshold, and the setting of an area of uncertainty (,grey area'). We propose that the use of a standard area for mitotic quantification and of a grey area in mitotic counting protocols will facilitate the application of mitotic counting in diagnostic and prognostic pathology. [source] Estradiol levels in prepubertal boys and girls , analytical challengesINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 5 2004Katrine Bay Summary Increasing evidence points at an important function of low concentrations of estradiol (E2) in prepubertal boys and girls. E2 serum levels in prepubertal children are, however, often immeasurable in conventional E2 assays. This strongly hampers further investigation of the physiological relevance of E2 in children. In addition, there is an increasing concern of the potential effect of exposure to endocrine disrupters with estrogenic or antiandrogenic activity on pubertal development. A requirement of assessing the instance for this concern, adds further to the demands for applicable methodologies for the evaluation of the sensitivity of the organism to low E2 concentrations. Traditionally, E2 is measured by use of the radioimmunoassay (RIA). As an ultrasensitive alternative to the RIA, a recombinant cell bioassay has been developed. In this review, methodological aspects for these methods of analysis are examined and their applicability for evaluation of low E2 serum concentrations in children is estimated. Furthermore, available data on E2 levels in prepubertal boys and girls are evaluated and discussed, taking into consideration the limitations of the methods of analysis. In conclusion, there is a pronounced demand for new and improved methods of analysis for accurate and sensitive evaluation of low concentrations of E2. [source] Low number of Y-chromosome deletions in infertile azoospermic men at a Swedish andrology centreINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 4 2000Christina Österlund Recent studies have strongly indicated that at least three regions [azoospermia factor (AZF) a,c] on the long arm of the Y-chromosome code for factors involved in spermatogenesis. In order to reveal the prevalence of microdeletions in these regions in a Swedish population, 192 men consecutively referred to our andrology unit due to infertility and showing oligozoospermia (n=53) or azoospermia (n=139) but no obstruction or hormonal disturbances, were investigated. For this study we used a multiplex polymerase chain reaction (PCR) method including 13 pairs of primers divided into five different primer mixes. It was found that four men, all with azoospermia, had deletions including part of the AZFb region and probably the entire AZFc region. Testis biopsies showed different morphology ranging from absence of germ cells to hypospermatogenisis. Of special interest was one patient that was first investigated 10 years ago due to primary infertility and oligozoospermia. Today he has developed azoospermia. It is concluded that the number of patients with microdeletions on the Y chromosome is rather low (less than 3% in highly selected azoospermic men) in our study compared to a number of other studies in which a 1,55% incidence have been reported. It is possible that ethnic differences, selection criteria and methodological aspects can contribute to the difference between the present and previous studies. [source] Evaluation of predictors of mortality in Frontotemporal Dementia,methodological aspectsINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 7 2003A. Gräsbeck Abstract Objectives To retrospectively evaluate pre-diagnostic clinical features (predictors) of mortality in frontotemporal dementia (FTD). The main aim was to investigate if there were indications against interpreting missing data as signs of absence. Material and methods 96 cases with FTD, here defined as Dementia in Pick's disease according to ICD-10. The predictors were behavioural/psychiatric features, language impairment and neurological deficits up to the date of diagnosis. Each predictor was rated as present (Yes), absent (No) or not recorded (Missing), and evaluated according to its distribution and mortality pattern: if a feature was not recorded because it was absent, the mortality of the Missing and the No-category should hypothetically be close. Statistical methods included Kaplan-Meier survival curves and Cox regression analyses. Results Neurological deficits and language impairments were frequently recorded as present or absent, while non-recordings were more prevalent among the behavioural/psychiatric features. Some features were excluded as predictors because they showed too little variation. Analyses of the survival pattern indicated that in some features, the observations of the Missing-category could be interpreted as absence of the symptoms. In other features these observations had to be regarded as truly missing. Conclusions In the retrospective evaluation of predictors of mortality a method for treating missing data was applied. The interpretation of non-recordings as signs of absence was supported by the analyses of the survival patterns in some of the studied features. However, the study underscores the importance of systematic estimations of pre-diagnostic clinical features in dementia. Copyright © 2003 John Wiley & Sons, Ltd. [source] Brief measure of expressed emotion: internal consistency and stability over timeINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 4 2003Seija Sandberg Consultant, Senior Lecturer Abstract The study examined three methodological aspects of expressed emotion (EE) as assessed in the course of PACE (Psychosocial Assessment of Childhood Experiences) interviews with a parent. In a sample of 87 children, aged 6,13 years, enrolled in a prospective study examining the role of stress on the course of asthma, EE was assessed at three time points, 9 months apart. A high degree of agreement was found among the three concurrent measures of negative and positive EE (kappas from 0.74 to 0.97, and from 0.45 to 0.88, respectively; p , 0.0001 in all instances). The temporal stability of all measures was lower, although statistically significant in all but 2 instances (kappas from 0.19 to 0.59, and from 0.11 to 0.39, respectively). The temporal stability across measures, as well as across interviewers and over time, was broadly similar (kappas from 0.21 to 0.56 for negative EE, and from 0.09 to 0.38 for positive EE, with all but three of the 36 statistically significant). The findings provide support for the underlying assumptions of the PACE-EE and show the utility of measures based on just very brief periods of non-directive interviewing, making them practical in a wide range of studies with EE just one of a larger set of measures. Copyright © 2003 Whurr Publishers Ltd. [source] Reviews: A review of hereditary and acquired coagulation disorders in the aetiology of ischaemic strokeINTERNATIONAL JOURNAL OF STROKE, Issue 5 2010Lonneke M. L. De Lau The diagnostic workup in patients with ischaemic stroke often includes testing for prothrombotic conditions. However, the clinical relevance of coagulation abnormalities in ischaemic stroke is uncertain. Therefore, we reviewed what is presently known about the association between inherited and acquired coagulation disorders and ischaemic stroke, with a special emphasis on the methodological aspects. Good-quality data in this field are scarce, and most studies fall short on epidemiological criteria for causal inference. While inherited coagulation disorders are recognised risk factors for venous thrombosis, there is no substantial evidence for an association with arterial ischaemic stroke. Possible exceptions are the prothrombin G20210A mutation in adults and protein C deficiency in children. There is proof of an association between the antiphospholipid syndrome and ischaemic stroke, but the clinical significance of isolated mildly elevated antiphospholipid antibody titres is unclear. Evidence also suggests significant associations of increased homocysteine and fibrinogen concentrations with ischaemic stroke, but whether these associations are causal is still debated. Data on other acquired coagulation abnormalities are insufficient to allow conclusions regarding causality. For most coagulation disorders, a causal relation with ischaemic stroke has not been definitely established. Hence, at present, there is no valid indication for testing all patients with ischaemic stroke for these conditions. Large prospective population-based studies allowing the evaluation of interactive and subgroup effects are required to appreciate the role of coagulation disorders in the pathophysiology of arterial ischaemic stroke and to guide the management of individual patients. [source] Cell-free synthesis of 15N-labeled proteins for NMR studiesIUBMB LIFE, Issue 9 2005Kiyoshi Ozawa Abstract Modern cell-free in vitro protein synthesis systems present powerful tools for the synthesis of isotope-labeled proteins in high yields. The production of selectively 15 N-labeled proteins from 15 N-labeled amino acids is particularly economic and yields are often sufficient to analyze the proteins very quickly by two-dimensional NMR spectra recorded of the crude reaction mixture without concentration or chromatographic purification of the protein. We review methodological aspects of cell-free in vitro protein synthesis based on an Escherichia coli cell extract, in particular with regard to the production of 15 N-labeled proteins for analysis by NMR spectroscopy. IUBMB Life, 57: 615-622, 2005 [source] Physicochemical characterization of carrageenans,A critical reinvestigationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Gisela Berth Abstract Kappa-, iota-, and lambda-carrageenan (food grade) were analyzed by static light scattering (MALS in batch mode) in 0.1M NaNO3 at 25 and 60°C, earlier heated up to 90°C or not. At 25°C, there was a strong tendency for a concentration-dependent aggregation in the order lambda < kappa < iota. At 60°C, all samples were molecularly dispersed. The strongly temperature-dependent refractive index increments (equilibrium dialysis) differ. Data interpretation in terms of the wormlike chain model using the Skolnik-Odijk-Fixman approach led to an intrinsic persistence length around 3 to 4 nm and expansion factors as high as 1.5 and above in a thermodynamically good solvent for all three types. Triple-detector HPSEC (DRI, MALS, viscometry) on the three commercial samples plus a degraded (by acidic hydrolysis) kappa-carrageenan in the same solvent/eluant at 60°C yielded a uniform and slightly curved [,]- M relationship for 5 × 103 , M/(g mol) , 3 × 106 and a nearly identical molar mass dependence of the radius of gyration. HPSEC at 25°C on kappa-carrageenan confirmed formation of soluble aggregates. Special emphasis was put on analytical and methodological aspects. The reliability of the experimental data was demonstrated by analogous measurements on dextran calibration standards. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Effect of heating rate on kinetics of high-temperature reactions: Mo-Si systemAICHE JOURNAL, Issue 1 2005Suren L. Kharatyan Abstract By using the Computer Assisted Electrothermography (CAE) method and taking the molybdenum-silicon system as an example, the influence of preheating rate on the kinetics of gasless reactions at high temperatures (above Si melting point, 1683 K) is studied. It is shown that an increase of heating rate Vh in the range 10,105 K/s, leads to a substantial increase in the rate of chemical reaction. At high heating rates (>103 K/s), the first stage of interaction involves rapid reaction due to the direct dissolution of Mo in the Si melt. Furthermore, the formation of MoSi2 phase, owing both to crystallization from eutectic (MoSi2 -Si) melt and reaction-diffusion mechanism, is primarily responsible for the observed intensive heat release under these conditions. At lower Vh, a thin layer of Mo5Si3 phase formed at earlier stages (solid-solid interaction) significantly retards reaction at higher temperatures and changes the mechanism of interaction. Some methodological aspects of using the CAE technique for kinetic studies are also discussed. © 2004 American Institute of Chemical Engineers AIChE J, 51: 261,270, 2005 [source] Outcome Variables and Their Assessment in Alcohol Treatment Studies: 1968-1998ALCOHOLISM, Issue 10 2003John W. Finney Background: This article provides a historical overview of the assessment of outcome variables in alcohol treatment studies that were first published between 1968 and 1998. The review focuses on changes over time in (1) the number of outcome variables and the number of different types of outcome variables assessed, (2) the likelihood of assessing specific types of outcome variables, (3) the methods used to assess outcome variables, and (4) the status of outcome assessment in more recent studies first published between 1990 and 1998. Methods: Reports of 357 alcohol treatment trials with two or more treatment/control groups were coded with respect to the number and types of outcome variables assessed, sources of outcome data, and methodological aspects of outcome assessment. Results: Although the number of outcome variables assessed in studies, on average, did not increase significantly over time, the number of different types of outcome variables did increase. An expected decrease in the assessment of categorical abstinence was not found, but another categorical variable, global ratings of drinking improvement, did decrease over time. More recent studies were more likely to assess such continuous variables as time abstinent, alcohol consumption, time drinking, dependence symptoms, and drinking-related problems. Physiological markers of drinking/alcohol misuse also were assessed more frequently in later years. Some aspects of outcome assessment methods exhibited improvement over time; validity data were more likely to be provided or cited, and self-reports of drinking behaviors were more likely to be corroborated in studies first published in more recent years. However, the percentages of studies that provided/cited reliability data for outcome measures, indicated that follow-up data collectors were not affiliated with treatment and were unaware of respondents' treatment conditions, and reported that respondents were alcohol-free at follow-up did not rise significantly over time. Conclusions: Although the methods of outcome assessment improved between 1968 and 1998, much room for improvement remains. [source] X-ray absorption spectroscopy to watch catalysis by metalloenzymes: status and perspectives discussed for the water-splitting manganese complex of photosynthesisJOURNAL OF SYNCHROTRON RADIATION, Issue 1 2003Holger Dau Understanding structure,function relations is one of the main interests in the molecular biosciences. X-ray absorption spectroscopy of biological samples (BioXAS) has gained the status of a useful tool for characterization of the structure of protein-bound metal centers with respect to the electronic structure (oxidation states, orbital occupancies) and atomic structure (arrangement of ligand atoms). Owing to progress in the performance characteristics of synchrotron radiation sources and of experimental stations dedicated to the study of (ultra-dilute) biological samples, it is now possible to carry out new types of BioXAS experiments, which have been impracticable in the past. Of particular interest are approaches to follow biological catalysis at metal sites by characterization of functionally relevant structural changes. In this article, the first steps towards the use of BioXAS to `watch' biological catalysis are reviewed for the water-splitting reactions occurring at the manganese complex of photosynthesis. The following aspects are considered: the role of BioXAS in life sciences; methodological aspects of BioXAS; catalysis at the Mn complex of photosynthesis; combination of EXAFS and crystallographic information; the freeze-quench technique to capture semi-stable states; time-resolved BioXAS using a freeze-quench approach; room-temperature experiments and `real-time' BioXAS; tasks and perspectives. [source] How to make your article more acceptable for the statistical reviewer,NEUROUROLOGY AND URODYNAMICS, Issue 3 2007Peter Herbison Abstract Many medical articles have problems with methodological aspects. To help prevent this, medical statisticians should be more involved in all aspects of medical research. Having more statistical reviewing of manuscripts submitted to journals should also help, but will not cure the problem. This paper makes some suggestions that may help authors make manuscripts more acceptable methodologically, but there is no substitute for statistical involvement throughout the research process. Neurourol. Urodynam. 26:318,322, 2007. © 2007 Wiley-Liss, Inc. [source] Herpes simplex virus type 1 morphogenesis and virus-cell interactions: significance of cytoskeleton and methodological aspectsAPMIS, Issue 2006Helle Lone Jensen First page of article [source] Luminescence dating of Würmian (Weichselian) proglacial sediments from Switzerland: methodological aspects and stratigraphical conclusionsBOREAS, Issue 2 2007FRANK PREUSSER Proglacial deposits from three independently dated sites in the Swiss lowlands were investigated by optically stimulated luminescence (OSL) to test the reliability of the applied dating approach. Using the single-aliquot regenerative-dose technique applied to small aliquots of quartz revealed that in all samples the OSL signal was differentially bleached prior to deposition. A statistical approach is introduced to extract the fraction of aliquots in which the OSL was apparently set to zero at deposition. The statistical treatment provided OSL ages in good consistency with independent age control. However, some uncertainties remain with this approach, since it is difficult to assess the natural scatter caused by dose-rate inhomogeneity exactly. The available data set implies that glaciers reached the Swiss lowlands prior to about 25 000 yr ago. Previously published data from other sites demonstrate that glaciers were present in lowland Switzerland up to about 20000 yr ago. Furthermore, one OSL date of about 70 000 yr for proglacial outwash sediments points to the presence of the Rhōne Glacier in the Lake Neuchātel area during the middle part of the Late Pleistocene. [source] Silence in the Context of ,Child Voice'CHILDREN & SOCIETY, Issue 1 2010Ann Lewis Recent decades have seen growing enthusiasm internationally for the concept and practice of ,child voice'. This was encapsulated in, and stimulated, by Article 12 of the 1989 United Nations Convention on the Rights of the Child. This article presents the case for incorporating the equally important concept of ,child silence' in both research and applied contexts. ,Child voice' has become a powerful moral crusade and consequently criticism of voice has been muted. This is despite the growing articulation of reservations about ,child voice' in various research and applied contexts. Two particular sets of emerging concerns are discussed: one set is around the purposes behind such engagement with children; and one set relates to the ethical protocols involved. Finally, the article makes a series of recommendations for researchers working in the fields of ,child voice'. These concern five methodological aspects: recognising, noting, responding to, interpreting and reporting silence from children. It is concluded that it is timely to take a step back from assumed support for ,child voice' as necessarily ,a good thing'. Rather, we need to consider more reflexively how, why and when ,child voice' is realised in co-constructed research and professional contexts. [source] | |||||||||||||||||||||||||||||||