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Standard Methodology (standard + methodology)
Selected AbstractsImplied trees in illiquid markets: A Choquet pricing approachINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 6 2002Silvia Muzzioli Implied trees are necessary to implement the risk neutral valuation approach, and standard methodologies for their derivation are based on the validity of the put call parity. However, in illiquid markets the put call parity fails to hold, and the uniqueness of the artificial probabilities leaves room for an interval. The contribution of this article is twofold. First we propose a methodology for the derivation of implied trees in illiquid markets. Such a methodology, by contrast with standard ones, takes into account the information stemming both from call and put prices. Second, we set up a framework for pricing derivatives written on an underlying asset traded on an illiquid market. To this end we have extended the Choquet integral definition to account for interval payoffs of the underlying asset. The price interval we obtain may be interpreted as a bid-ask price quoted by the intermediary issuing the derivative security. © 2002 Wiley Periodicals, Inc. [source] From ice age to modern: a record of landscape change in an Andean cloud forestJOURNAL OF BIOGEOGRAPHY, Issue 9 2010B. G. Valencia Abstract Aim, To investigate the palaeoecological changes associated with the last ice age, subsequent deglaciation and human occupation of the central Andes. Location, Lake Pacucha, Peruvian Andes (13°36,26, S, 73°19,42, W; 3095 m elevation). Methods, Vegetation assemblages were reconstructed for the last 24 cal. kyr bp (thousand calibrated 14C years before present), based on pollen analysis of sediments from Lake Pacucha. An age model was established using 14C accelerator mass spectrometry dates on bulk sediment. Fossil pollen and sedimentological analyses followed standard methodologies. Results, Puna brava replaced the Andean forest at the elevation of Lake Pacucha at the Last Glacial Maximum (LGM). Deglaciation proceeded rapidly after 16 cal. kyr bp, and near-modern vegetation was established by c. 14 cal. kyr bp. The deglacial was marked by the range expansion of forest taxa as grassland taxa receded in importance. The mid-Holocene was marked by a lowered lake level but relatively unchanged vegetation. Quinoa and maize pollen were found in the latter half of the Holocene. Main conclusions, Temperatures were about 7,8 °C colder than present at this site during the LGM. The pattern of vegetation change was suggestive of microrefugial expansion rather than simple upslope migration. The mid-Holocene droughts were interrupted by rainfall events sufficiently frequent to allow vegetation to survive largely unchanged, despite lowering of the lake level. Human activity at the lake included a 5500-year history of quinoa cultivation and 3000 years of maize cultivation. [source] Antifungal susceptibility testing by flow cytometry: is it the future?MYCOSES, Issue 4 2006Luís André Vale-Silva Summary The current increase in the number and significance of fungal infections, the expanding armamentarium of antifungal agents, and the emergence of the problem of antifungal drug resistance have been intensifying the importance of antifungal susceptibility testing (AST). The Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS) in the United States and the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antimicrobial Susceptibility Testing (AFST-EUCAST) published standard methodologies in order to achieve higher reproducibility and allow direct inter-laboratory comparison of the susceptibility results. Nevertheless, several problems remain unresolved and the methods depend on long incubation periods of a minimum of 24 h (EUCAST) or even 48 h (CLSI). Over the last 15 years, successful applications of flow cytometric techniques to AST of both yeast and moulds have been reported. These techniques are based on the analysis of a great number of fungal cells individually and frequently rely on short incubation times of no more than a few hours. Considering these attributes, flow cytometry (FC) seems to have the potential to achieve clinical usefulness in the near future. The collection of data on the reproducibility of the results and on the correlation with clinical outcomes has barely started, however. Practical validation of the experimental methodologies is not granted before a significant amount of data addressing those questions is available. [source] Windbreaks as a pesticide drift mitigation strategy: a reviewPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 8 2001Tamer Ucar Abstract The use of natural and artificial barriers to mitigate pesticide drift from agricultural and forest applications is discussed. This technique has been considered as an alternative to current methods at a time when environmental concerns are under great public scrutiny. There has been a variety of research experiments on this subject from New Zealand to The Netherlands which have documented reductions in spray drift of up to 80,90%. However, there are still enormous data gaps to utilize this method accurately. The aerodynamic factors of wind barriers and shelter effects on crop growth and yield have been well investigated. In contrast, some of the important aspects of drift mitigation, eg porosity and turbulence, have been difficult to obtain and no standard methodologies are currently available to evaluate and classify windbreaks and shelterbelts or to determine their efficiency in reducing drift. Thus there is a significant opportunity to incorporate windbreaks into the tool set of drift mitigation tactics. Government policies, initiatives, legislation, etc, which currently address water quality, BMP, stewardship, buffers, etc, are issues which so far have not included windbreaks as a valuable drift mitigation strategy. © 2001 Society of Chemical Industry [source] A new approach to aid the characterisation and identification of metabolites of a model drug; partial isotope enrichment combined with novel formula elucidation softwareRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 2 2009Kirsten Hobby This work describes the identification of ,isotopically enriched' metabolites of 4-cyanoaniline using the unique features of the software package ,Spectral Simplicity'. The software is capable of creating the theoretical mass spectra for partially isotope-enriched compounds, and subsequently performing an elemental composition analysis to give the elemental formula for the ,isotopically enriched' metabolite. A novel mass spectral correlation method, called ,FuzzyFit', was employed. ,FuzzyFit' utilises the expected experimental distribution of errors in both mass accuracy and isotope pattern and enables discrimination between statistically probable and improbable candidate formulae. The software correctly determined the molecular formulae of ten previously described metabolites of 4-cyanoaniline confirming the technique of partial isotope enrichment can produce results analogous to standard methodologies. Six previously unknown species were also identified, based on the presence of the unique ,designer' isotope ratio. Three of the unknowns were tentatively identified as N-acetylglutamine, O-methyl-N acetylglucuronide and a putative fatty acid conjugate. The discovery of a significant number of unknown species of a model drug with a comprehensive history of investigation highlights the potential for enhancement to the analytical process by the use of ,designer' isotope ratio compounds. The ,FuzzyFit' methodology significantly aided the elucidation of candidate formulae, by provision of a vastly simplified candidate formula data set. Copyright © 2008 John Wiley & Sons, Ltd. [source] EVALUATION OF THE APPLICABILITY OF CONVENTIONAL METHODS FOR THE CHEMICAL CHARACTERIZATION OF WATERLOGGED ARCHAEOLOGICAL WOODARCHAEOMETRY, Issue 4 2010BENEDETTO PIZZO A series of 112 waterlogged archaeological wood samples of different provenances, wood species, burial times and states of preservation were analysed with the aim of assessing the validity (in terms of limits and reliability) of procedures conventionally used in the pulp and paper industry, to evaluate the state of preservation of decayed wood. In particular, the extent of any damage wrought on decayed wood tissue by the repetitive cycles that characterize these procedures was evaluated as a function of the degradation of the samples. The results indicated that standard methodologies give reliable measurements regardless of the extent of wood decay. However, it is essential to compare these data with those of non-decayed wood that has been measured using the same procedures to take account of the errors that are inherent in these methodologies and that affect measurements. [source] Estimating annual N2O emissions from agricultural soils in temperate climatesGLOBAL CHANGE BIOLOGY, Issue 10 2005Caroline Roelandt Abstract The Kyoto protocol requires countries to provide national inventories for a list of greenhouse gases including N2O. A standard methodology proposed by the Intergovernmental Panel on Climate Change (IPCC) estimates direct N2O emissions from soils as a constant fraction (1.25%) of the nitrogen input. This approach is insensitive to environmental variability. A more dynamic approach is needed to establish reliable N2O emission inventories and to propose efficient mitigation strategies. The objective of this paper is to develop a model that allows the spatial and temporal variation in environmental conditions to be taken into account in national inventories of direct N2O emissions. Observed annual N2O emission rates are used to establish statistical relationships between N2O emissions, seasonal climate and nitrogen-fertilization rate. Two empirical models, MCROPS and MGRASS, were developed for croplands and grasslands. Validated with an independent data set, MCROPS shows that spring temperature and summer precipitation explain 35% of the variance in annual N2O emissions from croplands. In MGRASS, nitrogen-fertilization rate and winter temperature explain 48% of the variance in annual N2O emissions from grasslands. Using long-term climate observations (1900,2000), the sensitivity of the models with climate variability is estimated by comparing the year-to-year prediction of the model to the precision obtained during the validation process. MCROPS is able to capture interannual variability of N2O emissions from croplands. However, grassland emissions show very small interannual variations, which are too small to be detectable by MGRASS. MCROPS and MGRASS improve the statistical reliability of direct N2O emissions compared with the IPCC default methodology. Furthermore, the models can be used to estimate the effects of interannual variation in climate, climate change on direct N2O emissions from soils at the regional scale. [source] COMPARATIVE STUDY OF SHELL SWAB AND SHELL CRUSH METHODS FOR THE RECOVERY OF SALMONELLA FROM SHELL EGGSJOURNAL OF FOOD SAFETY, Issue 4 2008T. KAWASAKI ABSTRACT Swabbing is the standard methodology for the recovery of resident microorganism from shell eggs in Japan. A comparative study of shell swab (SW) and shell crush (CR) techniques was performed to recover the laboratory-inoculated Salmonella from shell eggs. It was found that the recovery of Salmonella by CR methods was significantly higher (4.5,7.5 log cfu/egg) than that of SW methods (3.1,6.3 log cfu/egg). However, analyses with quantitative real-time polymerase chain reaction (invA as a target gene), fluorescent microscopic and quantitative analyses with a Live/Dead BacLight bacterial viability kit revealed that not all of the inoculated Salmonella spp. populations were recovered as intact cells by either method. The chemiluminescent bacterial viability assay showed that chemiluminescence intensity (CI) began to increase after 30 min in CR samples; on the other hand, SW samples did not show any increase in CI for 2 h. These results suggest that SW might cause more damage and lethality to cells than CR. In addition, to determine the most appropriate method for recovering resident aerobic bacteria, coliforms and Salmonella spp from shell eggs, 4,000 commercial eggs were collected and sampled by shell rinse (SR) and CR techniques using phosphate-buffered saline (PBS) warmed to different temperatures. PBS at 37C was found to be the best recovery solution and temperature, respectively, for recovering aerobic microorganisms from shell eggs by both methods and the CR methods recovered a higher population than did the SR methods (4.9 versus 5.8 log cfu/egg for SR and CR methods, respectively; n = 500 eggs/method). Therefore, the CR method along with recovery buffer (PBS) at 37C could be an effective technique for the recovery of microorganisms from post-processed shell eggs. PRACTICAL APPLICATIONS There is a need to develop a rapid and highly sensitive method for the recovery of microorganisms from shell eggs. Such recovery methods are also useful for evaluating the efficacy of newly developed shell egg disinfection techniques. Many methods involving rinsing, swabbing, and crushing of shell eggs have been reported; however, we performed a comparative study of the method used to recover the Salmonella from shell eggs. We found that the shell crush method (CR) was superior to the shell swab method (SW) for the recovery of Salmonella spp., and phosphate-buffered saline (PBS) at 37C was found to be the best recovery solution and temperature, respectively, for recovering microorganisms from shell eggs by both methods. Therefore, the CR method along with recovery buffer (PBS) at 37C could be an effective technique for the recovery of microorganisms from post-processed shells. Use of this method could be recommended for the microbial evaluation of post-processed shell eggs in industries. [source] Quantitative MRI for the assessment of bone structure and function,NMR IN BIOMEDICINE, Issue 7 2006Felix W. Wehrli Abstract Osteoporosis is the most common degenerative disease in the elderly. It is characterized by low bone mass and structural deterioration of bone tissue, leading to morbidity and increased fracture risk in the hip, spine and wrist,all sites of predominantly trabecular bone. Bone densitometry, currently the standard methodology for diagnosis and treatment monitoring, has significant limitations in that it cannot provide information on the structural manifestations of the disease. Recent advances in imaging, in particular MRI, can now provide detailed insight into the architectural consequences of disease progression and regression in response to treatment. The focus of this review is on the emerging methodology of quantitative MRI for the assessment of structure and function of trabecular bone. During the past 10 years, various approaches have been explored for obtaining image-based quantitative information on trabecular architecture. Indirect methods that do not require resolution on the scale of individual trabeculae and therefore can be practiced at any skeletal location, make use of the induced magnetic fields in the intertrabecular space. These fields, which have their origin in the greater diamagnetism of bone relative to surrounding marrow, can be measured in various ways, most typically in the form of R2,, the recoverable component of the total transverse relaxation rate. Alternatively, the trabecular network can be quantified by high-resolution MRI (µ-MRI), which requires resolution adequate to at least partially resolve individual trabeculae. Micro-MRI-based structure analysis is therefore technically demanding in terms of image acquisition and algorithms needed to extract the structural information under conditions of limited signal-to-noise ratio and resolution. Other requirements that must be met include motion correction and image registration, both critical for achieving the reproducibility needed in repeat studies. Key clinical applications targeted involve fracture risk prediction and evaluation of the effect of therapeutic intervention. Copyright © 2006 John Wiley & Sons, Ltd. [source] The content of optometric eye examinations for a young myope with headachesOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 5 2008Rakhee Shah Abstract Background:, A recent review found standardised patient (SP) methodology to be the gold standard methodology for evaluating clinical care. We used this to investigate the content of optometric eye care for a young myopic patient with headaches suggestive of migraine. Methods:, We recruited 100 community optometrists who consented to be visited by an unannounced actor for an eye examination and to have that eye examination recorded. The actor received extensive training to enable accurate reporting of the content of the eye examinations, via an audio recording and a checklist completed for each clinical encounter. The actor presented as a 20-year-old student seeking a private eye examination and complaining of symptoms suggestive of migraine headaches. The results of each clinical encounter were recorded on a pre-designed checklist based on evidence-based reviews on headaches, clinical guidelines and the views of an expert panel of optometrists. Results:, The presence of headache was detected in 98% of cases. Eight standard headache questions were considered to be the gold standard for primary care headache investigation. Although none of the optometrists asked all of these questions, 22% asked at least four of the eight questions. Sixty-nine per cent of practitioners asked the patient to seek a medical opinion regarding the headaches. The proportion of the tests recommended by the expert panel that was carried out varied from 33% to 89% and the durations of the eye examination varied from 5 to 50 min. Conclusion:, SP encounters are an effective way of measuring clinical care within optometry and should be considered for further comparative measurements of quality of care. As in research using SPs in other healthcare disciplines, our study has highlighted substantial differences between different practitioners in the duration and depth of their clinical investigations. This highlights the fact that not all eye examinations are the same and that there is no such thing as a ,standard sight test'. We recommend that future optometric continuing education could usefully focus on migraine diagnosis and assessment. [source] Methodological issues related to exhaled nitric oxide measurement in children aged four to six yearsPEDIATRIC PULMONOLOGY, Issue 2 2005Edward Napier MBBS Abstract This study was designed to test five methodological issues related to measurement of fractional exhaled nitric oxide (FENO) in children aged 4,6 years using commercially available apparatus. Participants attended two randomly selected schools. A respiratory questionnaire was completed. Measurements of FENO were made on successive days, using a NIOX® analyzer employing standard or modified methodologies. Ninety-one children participated in the study (mean age, 5.3 years; 46 boys). Using a standard methodology (n,=,61), FENO was successfully measured in 28 (46%) children, 1/12 aged 4 years, 12/25 aged 5 years, and 15/24 aged 6 years (trend test P,=,0.01). On the first assessment, FENO could be determined in more boys than girls (64% vs. 30%, respectively, P,=,0.008), but this gender difference was not apparent on the second assessment. Exhaled NO was reproducible over a 24-hr period; the mean difference between repeated measurements of natural log (ln) FENO was 0.016 parts per billion (ppb) (95% confidence limits, ,0.479, 0.511), n,=,20. Data from 35 assessments showed that values of FENO did not alter over nine individual, successive measurements. Use of a modified methodology in 30 children increased success in obtaining FENO, but these values were unreliable. In conclusion, measurements of FENO can be obtained in the majority of 5- and 6-year-old but not 4-year-old children. Exhaled NO measurements were reproducible over a 24-hr interval, and did not change over up to nine expiratory maneuvers in these young children. Pediatr Pulmonol. 2005; 40:97,104. © 2005 Wiley-Liss, Inc. [source] Systematic review of the literature for the use of oesophageal Doppler monitor for fluid replacement in major abdominal surgeryANAESTHESIA, Issue 1 2008S. M. Abbas Summary The use of intra-operative Doppler oesophageal probes provides continuous monitoring of cardiac output. This enables optimisation of intravascular volume and tissue perfusion in major abdominal surgery, which is thought to reduce postoperative complications and shorten hospital stay. Medline and EMBASE were searched using the standard methodology of the Cochrane collaboration for trials that compared oesophageal Doppler monitoring with conventional clinical parameters for fluid replacement in patients undergoing major elective abdominal surgery. Data from randomised controlled trials were entered and analysed in Meta-view in Rev -Man 4.2 (Nordic, Denmark). We included five studies that recruited 420 patients undergoing major abdominal surgery who were randomly allocated to receive either intravenous fluid treatment guided by monitoring ventricular filling using oesophageal Doppler monitor or fluid administration according to conventional parameters. Pooled analysis showed a reduced hospital stay in the intervention group. Overall, there were fewer complications and ICU admissions, and less requirement for inotropes in the intervention group. Return of normal gastro-intestinal function was also significantly faster in the intervention group. Oesophageal Doppler use for monitoring and optimisation of flow-related haemodynamic variables improves short-term outcome in patients undergoing major abdominal surgery. [source] Geographical information systems-based models for offshore floating marine fish cage aquaculture site selection in Tenerife, Canary IslandsAQUACULTURE RESEARCH, Issue 10 2005Oscar M Pérez Abstract The present study focuses on the development of a standard methodology for selection of suitable sites for offshore (exposed) marine fish-cage farming (floating cages) of seabream (Sparus aurata) and seabass (Dicentrarchus labrax) in an island environment, using Tenerife as an example. Site selection is a key factor in any aquaculture operation, affecting both success and sustainability and can solve conflicts between different activities, making a rational use of the coastal space. Site selection was achieved by using geographical information systems (GIS)-based models and related technology to support the decision-making process. The framework for spatial multicriteria decision analysis used in this study began with a recognition and definition of the decision problem. Subsequently, 31 production functions (factors and constraints) were identified, defined and subdivided into eight submodels. These were then integrated into a GIS database in the form of thematic layers and later scored for standardization. At this stage, the database was verified by field sampling to establish the quality of data used. The decision maker's preferences were incorporated into the decision model by assigning weights of relative importance to the evaluation under consideration. These, together with the thematic layers, were incorporated using multicriteria evaluation techniques and simple overlays to provide an overall assessment of possible alternatives. The integration, manipulation and presentation of the results by means of GIS-based models in this sequential and logical flow of steps proved to be very effective for helping the decision-making process of site selection. Tenerife has very favourable environmental conditions for culture of marine fish and there are no totally unsuitable sites for cage farming identified in this study. On the other hand, there are few very suitable sites (high scores) either, principally due to the heavy use of the coastline and the conflicts between different users. From the 228 km2 of available area for siting cages in the coastal regions with depth less than 50 m, the total area suitable for siting cages (scores 6,8) was 37 km2. There are only 0.51 km2 of very suitable areas (score 8) and approximately 5.37 km2 of suitable (score 7), most of these being located in the southeast of the island. These relatively small areas of suitability should be put into the context of the wider use of the coastal environment around Tenerife. [source] | ||||||||||||||||