Home About us Contact
|
Home About us Contact | ||
|
|
||
New Parameter (new + parameter)
Terms modified by New Parameter Selected AbstractsEmbryonic Ammonoid Shell Features: Intraspecific Variation RevisitedPALAEONTOLOGY, Issue 1 2001Isabelle Rouget Two samples of ammonoids belonging to the Oppeliidae, Sublunuloceras virguloidesHecticoceras (Brightii) canaliculatum, are analyzed to estimate the intraspecific variability of embryonic shell features. The study of embryonic shell characters reveals two main shapes of protoconch, flattened and round. Prosiphons may be straight or slightly curved. New parameters for area are added to the linear parameters commonly found in the literature. Prosiphon length and caecum area vary greatly whereas protoconch and ammonitella diameter vary only slightly, and the ammonitella angle is almost constant. The protoconch-to-ammonitella size ratio behaves differently in each species, suggesting different patterns of embryonic growth. We compare our results with published data and discuss their significance for species determination and ontogenetic interpretation. The main finding is that intraspecific embryonic variation is greater than was previously believed. [source] New parameters in the interpretation of exercise testing in women: QTC dispersion and QT dispersion ratio differenceCLINICAL CARDIOLOGY, Issue 4 2002Kurtulu, Özdemr M.D. Abstract Background: It has been reported that the increase of QT dispersion (QTD) that occurs due to increased inhomogeneity of the ventricular repolarization because of transient ischemia obtained by standard 12-lead electrocardiogram (ECG), the changes during exercise, and the differences between exercise and rest increase the accuracy of exercise test in the diagnosis of coronary artery disease (CAD). Hypothesis: This study was designed to investigate the value of QTD parameters, which are reported to increase the diagnostic accuracy of exercise test in women. Methods: Ninety-seven women who had undergone coronary angiography and exercise test were evaluated for diagnosis of chest pain. QT dispersion was calculated using the measurements of the highest and lowest values of QT interval obtained by ECG during peak exercise. The QTc using Bazett's equation, and the QTD ratio (QTDR) using QT/RR were calculated, and QTcD and QTD ratios were obtained. The difference between QTcD and QTDR was determined by extracting the rest values from the exercise values. Results: The groups with normal coronaries (n = 48), single-vessel CAD (n= 24), and multivessel CAD (n= 25) were compared. The obtained QTD parameters at peak exercise and their differences between exercise and rest were found to be significantly increased in patients with CAD (p<0.001). Furthermore, these parameters were found to be higher in the patients with multivessel CAD than in those with single-vessel disease (p < 0.05). With the parameters QTcD > 60 ms and QTDR > 10%, greater sensitivity and specificity were obtained compared with ST-segment depression. The highest diagnostic accuracy was obtained with the QTD parameters calculated from the differences between rest and exercise values. The diagnostic accuracy of the difference of QTcD > 15 ms and the difference of QTDR > 5% was relatively higher than the other parameters (sensitivity, specificity, and negative and positive predictor values are 84,88,84, 87% and 84, 96, 85, 95%, respectively). Conclusion: The use of QTD parameters as variables of ECG, which is easily obtainable in the evaluation of exercise ECG in women, increases the diagnostic accuracy of the exercise test. In addition, the evaluation of QTD variables may provide information about the incidence of CAD. [source] A New Echocardiographic Index for Assessing Left Ventricular Function and Mechanism of Mitral Regurgitation and Its Relation to Other Echocardiographic IndicesECHOCARDIOGRAPHY, Issue 6 2007Cemal Sag M.D. Objective: Mitral regurgitation (MR) is a progressive disease of the mitral valve, which can be primary or functional. The assessment of left ventricular function in MR is still troublesome. In this study, we evaluated the validity of a new parameter, total dt, in patients with MR. Methods: Forty patients with severe MR constituted the study group. According to the transesophageal echocardiographic evaluation, the patients were dichotomized into two groups: (1) Primary MR; n = 21, (2) Functional MR; n = 19. The total dt was defined as the sum of time intervals from 1 msto 3 ms (positive dt) and from 3 ms to 1 ms (negative dt) on the CW Doppler recording of MR jet. It was compared to other indices of left ventricular function and left ventricular geometry, including ejection fraction, fractional shortening, myocardial performance index, coaptation distance, left ventricular volume and diameter, sphericity index, and parameters of diastolic function. Result: The total dt correlated with myocardial performance index, coaptation distance, and sphericity index. It could differentiate between primary and functional MR with an area under curve of 0.878, followed by myocardial performance index with 0.860. The total dt > 104 ms was 79% sensitive and 81% specific for discrimination. Conclusion: The total dt is useful for assessing left ventricular function and also for differentiating primary MR from functional MR. [source] Cover Picture: Electrophoresis 8'09ELECTROPHORESIS, Issue 8 2009Article first published online: 20 APR 200 Issue no. 8 is an Emphasis Issue with 12 articles in Part I on various aspects of "Fundamentals and Methodologies" while the remaining 5 articles are grouped into Part II on "Bioanalysis". In addition, this issue includes a Fast Track article that demonstrates that "omic analyses unravels molecular changes in the brain and liver of a rat model for chronic Sake (Japanese alcoholic beverage) intake". Further selected topics from issue 8 are: Introducing a new parameter for quality control of proteome profiles: Consideration of commonly expressed proteins. (10.1002/elps.200800440) Improving sensitivity in micro-free flow electrophoresis using signal averaging. (10.1002/elps.200800497) [source] Linking flux network measurements to continental scale simulations: ecosystem carbon dioxide exchange capacity under non-water-stressed conditionsGLOBAL CHANGE BIOLOGY, Issue 4 2007KATHERINE E. OWEN Abstract This paper examines long-term eddy covariance data from 18 European and 17 North American and Asian forest, wetland, tundra, grassland, and cropland sites under non-water-stressed conditions with an empirical rectangular hyperbolic light response model and a single layer two light-class carboxylase-based model. Relationships according to ecosystem functional type are demonstrated between empirical and physiological parameters, suggesting linkages between easily estimated parameters and those with greater potential for process interpretation. Relatively sparse documentation of leaf area index dynamics at flux tower sites is found to be a major difficulty in model inversion and flux interpretation. Therefore, a simplification of the physiological model is carried out for a subset of European network sites with extensive ancillary data. The results from these selected sites are used to derive a new parameter and means for comparing empirical and physiologically based methods across all sites, regardless of ancillary data. The results from the European analysis are then compared with results from the other Northern Hemisphere sites and similar relationships for the simplified process-based parameter were found to hold for European, North American, and Asian temperate and boreal climate zones. This parameter is useful for bridging between flux network observations and continental scale spatial simulations of vegetation/atmosphere carbon dioxide exchange. [source] An enhanced constitutive model for crushable granular materialsINTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 6 2010Ali Daouadji Abstract Studies in the past have tried to reproduce the mechanical behaviour of granular materials by proposing constitutive relations based on a common assumption that model parameters and parameters describing the properties, including gradation of individual grains are inevitably linked. However successful these models have proved to be, they cannot account for the changes in granular assembly behaviour if the grains start to break during mechanical loading. This paper proposes to analyse the relation between grading change and the mechanical behaviour of granular assembly. A way to model the influence of grain breakage is to use a critical state-based model. The influence of the amount of grain breakage during loading, depending on the individual grain strength and size distribution, can be introduced into constitutive relations by means of a new parameter that controls the evolution of critical state with changes in grain size distribution. Experimental data from a calcareous sand, a quartz sand, and a rockfill material were compared with numerical results and good-quality simulations were obtained. The main consequences of grain breakage are increased compressibility and a gradual dilatancy disappearance in the granular material. The critical state concept is also enriched by considering its overall relation to the evolution of the granular material. Copyright © 2009 John Wiley & Sons, Ltd. [source] Flexural Strength Evaluation of Nonconstant Thickness Ceramic Floorings by Means of the Finite-Element MethodINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 2 2010Beatriz Defez The ceramic tile industry has become an extremely competitive sector. The entry of new Asian and South American manufacturers into the market is shifting the leadership in production and exports from the traditional clusters of Europe to China, Turkey, and Brazil. In this uncertain environment, enterprises should raise the quality and cut costs by means of new products and processes. Ceramic tiles lightened by carving of a deep back relief could give rise to a generation of new, efficient products. These tiles could be manufactured with fewer raw materials than the traditional ones, which may lead to saving of weight and energy. Additionally, a lighter final product improves working conditions on the shopfloor and at the building site. Nevertheless, lightened tiles are structurally different from traditional ones, and so is their mechanical behavior. Because tiles are constructive elements, it is necessary to know their response under typical loads and assure fulfillment of the valid standards. This paper aims at evaluating the flexural strength (R) of lightened ceramic floorings using solid three-dimensional modelling and the finite-element method, establishing a new formula for the application of the international standard ISO 10545 "Ceramic Tiles." In order to achieve this objective, one reference model and 48 different relief versions were designed, which underwent a simplified computational simulation of the bending test. In accordance with the Rankine criterion, the maximal stresses of each version were calculated, as much as their distribution. Next, we correlated the results defining a new parameter called "normalized thickness," defined as the thickness that a carved tile should have to behave as a traditional flooring under flexion. This parameter allowed the adjustment of the international standard ISO 10545 to this kind of a product, facilitating their certification and therefore their real introduction in the market. Finally, thanks to the collaboration of the company Keros Cerámica S. A., it was verified that the methodology used was appropriate. [source] Discrete thermodynamics of chemical equilibria and classical limit in thermodynamic simulationISRAEL JOURNAL OF CHEMISTRY, Issue 3-4 2007Boris Zilbergleyt This article sets forth comprehensive basic concepts of the discrete thermodynamics of chemical equilibrium as balance between internal and external thermodynamic forces. Conditions of chemical equilibrium in the open chemical system are obtained in the form of a logistic map, containing only one new parameter that defines the chemical system's resistance to external impact and its deviation from thermodynamic equilibrium. Solutions to the basic map are bifurcation diagrams that have quite traditional shape but the diagram areas feature specific meanings for chemical systems and constitute the system's domain of states. The article is focused on two such areas: the area of "true" thermodynamic equilibrium and the area of open chemical equilibrium. The border between them represents the classical limit, a transition point between the classical and newly formulated equilibrium conditions. This limit also separates regions of the system ideality, typical for isolated classical systems, and non-ideality due to the limitations imposed on the open system from outside. Numerical examples illustrating the difference between results of classical and discrete thermodynamic simulation methods are presented. The article offers an analytical formula to find the classical limit, compares analytical results with these obtained by simulation, and shows the classical limit dependence upon the chemical reaction stoichiometry and robustness. [source] Highlight of a compensation effect between filler morphology and loading on dynamic properties of filled rubbersJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010Franck Sosson Abstract This investigation highlighted the equivalence between carbon black (CB) loading and structure influences on dynamic mechanical properties in the linear behavior of several filled synthetic rubber compounds. Different morphologies (specific surface area and structure) of CB incorporated at different loadings were formulated to modulate the filler-rubber matrix interphase content, usually named "tightly bound rubber." Both reinforcement level and tightly bound rubber content were measured on each compound by dynamic mechanical analysis (DMTA) and by Soxhlet extraction and thermogravimetry (TGA) respectively. Then, a systematic description of their evolution was made against CB loading and morphology. These evolutions were attributed to the hydrodynamic effect which could be evaluated by the effective filler volume fraction. A new parameter , is defined, representing the effective filler volume fraction for each compound and it was calculated on the basis of experimental parameters. Results show good correspondences between , included both the hydrodynamic effects of the filled carbon black rubbers and dynamic mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Resistance Variation of Salmonella enterica Serovars to Pulsed Electric Fields TreatmentsJOURNAL OF FOOD SCIENCE, Issue 7 2003I. ÁLvarez ABSTRACT: Inactivation of Salmonella serovar Enteritidis and Salmonella serovar Typhimurium by pulsed electric fields has been investigated. A tertiary model based on the Weibull distribution (n= 0.262) and on a new parameter (ZPEF), accurately described the kinetics of inactivation of these microorganisms among 15 and 28 kV/cm. In the range of 19 to 28 kV/cm, this model also described previously published data of inactivation of serovar Senftenberg when the n value was set at 0.437. The ZPEF value for the 3 Salmonella serovars was 15.787 kV/cm. From 19 to 28 kV/cm, the time to inactivate 5 Log10 cycles of the population of serovar Enteritidis was 2.06 and 2.66 times lower than that to inactivate serovar Typhimurium and serovar Senftenberg, respectively. [source] Automated pre-ejection period variation indexed to tidal volume predicts fluid responsiveness after cardiac surgeryACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2009S. T. VISTISEN Background: Reliable continuous monitoring of fluid responsiveness is an unsolved issue in patients ventilated with low tidal volume. We hypothesised that variations in the pre-ejection period (PEP) defined as the time interval between electrocardiogram (ECG) R-wave and onset of systolic upstroke in arterial blood pressure could reliably predict fluid responsiveness in patients ventilated with moderately low tidal volume. Furthermore, we hypothesised that indexing dynamic parameters to tidal volume would improve their prediction. The aim was to refine and automate a previously suggested algorithm for PEP variation (,PEP) and to test this new parameter indexed to tidal volume (PEPV), as a marker of fluid responsiveness along with central venous pressure (CVP), pulse pressure variation (PPV) and ,PEP. Additionally, the aim was to evaluate the concept of indexing dynamic parameters to tidal volume. Methods: Arterial pressure, CVP, ECG and cardiac index (CI) were acquired from 23 mechanically ventilated post-cardiac surgery patients scheduled for volume expansion. PEPV, PPV and ,PEP were extracted. Results: Using responder/non-responder classification (response=change in CI>+15%), sensitivity and specificity were 100% and 83%, respectively, for PEPV, 94% and 83% for ,PEP, and 94% and 83% for PPV. CVP offered no relevant information. Tidal volume indexing improved sensitivity for ,PEP to 100%. Conclusion: In this study in post-cardiac surgery patients, a refined parameter, PEPV, predicted fluid responsiveness better than PPV and ,PEP. Our results suggest that dynamic parameters using variations in PEP should be indexed to tidal volume. [source] Influence of the pore structure on the properties of silica based reversed phase packings for LCJOURNAL OF SEPARATION SCIENCE, JSS, Issue 4 2005Zoltan Szabó Abstract This paper describes the preparation and investigation of new, highly loaded, monomeric, silica based, reversed phase C18 and C30 packings. The influence of pore structure and endcapping on the properties of C18 and C30 packings is described. Using hydrothermal procedures, silicas with predictable pore size (9.3,25.5 nm) and surface area have been prepared. Silylation with long chain silanes substantially alters the pore structure of the silica: pore size and pore volume decrease. A new parameter, the volumetric surface coverage [mm3×m,2] has been introduced. This parameter , calculated from on-column measured porosity data , indicates the pore volume portion occupied by the hydrocarbon chains. Endcapping does not significantly change the pore structure of the bonded phases. The reduced retentions (reduced with respect to unit area: [k/m2]) , a good measure for comparing the retention behaviour of packings with different surface areas , are similar for most of the phases, demonstrating good accessibility of the pores for the solutes. Slightly lower retentions were found on the endcapped than on the non-endcapped phases for probes with dense ,-electron system (e. g. polyaromatic hydrocarbons) demonstrating the contribution of silanophilic interactions to the retention. The phases had been successfully used for various demanding separations, e. g. for the separation of flavonoids, carotenoids, resveratrol, and tocopherol isomers, fullerenes, and anions. [source] LUBRICITY INDEX OF MAYONNAISEJOURNAL OF TEXTURE STUDIES, Issue 1 2003JAMES F. STEFFE ABSTRACT The Lubricity Index (LI) is defined as a new parameter to quantitatively evaluate mouthfeel. Rheological data were collected using a helical ribbon mixer viscometer with commercial mayonnaise products. The LI is calculated from changes in apparent viscosity due to temperature and moisture variations that mirror those found in the mouth during mastication. The rate of change in apparent viscosity with moisture and temperature was much lower with a fat free product than regular products resulting in a low LI value. The LI provides a basis for future efforts to understand, and mathematically model, the complicated process of fluid food mastication. [source] Olive oil extractability index as a parameter for olive cultivar characterisationJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2003Gabriel Beltrán Abstract Extractability, when applied to the olive oil extraction process is defined as the percentage of oil extracted from the total oil content of the fruit. In this work, extractability index (EI), a new parameter determined in a laboratory oil mill, has been studied for 24 olive (Olea europaea L) cultivars from the Olive Germplasm Bank Collection of Mengibar (Spain). In order to evaluate the genetic variability of this new parameter, the influence of cultivar and tree on EI variability has been analysed in olive fruits collected at the same ripening index. The results indicate that cultivar is the most important variation source. Thus olive oil extractability depends on extraction process variables and cultivar. Extractability index could be used together with pulp oil content (on a dry matter basis) as a parameter for olive cultivar characterisation and selection for breeding projects. Copyright © 2003 Society of Chemical Industry [source] Distinct physiological responses of two rice cultivars subjected to iron toxicity under field conditionsANNALS OF APPLIED BIOLOGY, Issue 2 2009R.J. Stein Abstract Iron toxicity is recognised as the most widely distributed nutritional disorder in lowland and irrigated rice, derived from the excessive amounts of ferrous ions generated by the reduction of iron oxides in flooded soils. Rice cultivars with variable degrees of tolerance to iron toxicity have been developed, and cultural practices such as water management and fertilisation can be used to reduce its negative impact. However, because of the complex nature of iron toxicity, few physiological data concerning tolerance mechanisms to excess iron in field conditions are available. To analyse the physiological responses of rice to iron excess in field conditions, two rice cultivars with distinct tolerance to iron toxicity [BR-IRGA 409 (susceptible) and IRGA 420 (tolerant)] were grown in two areas, with a well-established history of iron toxicity (in Camaquă, RS, Brazil) and without iron toxicity (in Cachoeirinha, RS, Brazil). Plants from the susceptible cultivar grown in the iron-toxic site showed lower levels of chlorophylls and soluble proteins (together with higher carbonyl levels) indicating photooxidative and oxidative damage. The toxic effects observed were because of the accumulation of high levels of iron and not because of any indirectly induced shoot deficiency of other nutrients. Higher activities of antioxidative enzymes were also observed in leaves of plants from the susceptible cultivar only in the iron-toxic site, probably as a result of oxidative stress rather than because of specific involvement in a tolerance mechanism. There was no difference between cultivars in iron accumulation in the symplastic and apoplastic space of leaves, with both cultivars accumulating 85,90% of total leaf iron in the symplast. However, susceptible plants accumulated higher levels of iron in low-molecular-mass fractions than tolerant plants. The accumulation of iron in the low-molecular-mass fraction probably has a direct influence on iron toxicity, and the adaptive strategy of tolerant plants may rely on their capacity to buffer the iron amounts present in the low mass fraction, a new parameter to be considered when evaluating tolerance to iron excess in field-cultivated rice plants. [source] Site, vine state and responsiveness to the application of growth regulator fruitsetting agentsAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 1 2009J.A. CONSIDINE Abstract Background and Aims:, This study was initiated to investigate local problems in obtaining consistent fruit-setting responses to a recommended treatment combination of gibberellic acid (GA3) and (2-chloroethyl)-trimethyl ammonium chloride (CCC), with vineyard managers returning to more traditional methods of either cincturing or applying 4-chlorophenoxy acetic acid (4-CPA). Methods and Results:, Five vineyard study sites located in the Chittering,Bindoon region of Western Australia were characterised by multivariate analysis using measures of vegetative and reproductive biomass. Two experiments were carried out in the vineyard to compare responses to combinations of GA3 and CCC. 4-CPA was used as an industry control. Bunch number was used as a novel covariate to adjust responses to individual vine and site factors. Berry volume increased in all vines and sites treated with GA3, irrespective of timing, but dry matter yield increased only in the youngest vineyards. The only site to show a significant response to CCC application was that with the highest vegetative biomass. Conclusions:, We conclude that site and management factors rather than growth regulator type, concentration or timing determined yield responsiveness (sugar production). Significance of the Study:, This study demonstrates a strong physiological and environmental effect on response to growth regulator application, reinforcing the importance of developing site-specific management practices. It shows how multivariate techniques may be used to characterise and compare vineyards, and also, how analysis of covariance using a new parameter, bunch number, may be used to enhance statistical of analysis of field experiments. [source] 2354: The range of waveform score of Ocular Response AnalyzerTM (ORA) in healthy subjects: interim analysisACTA OPHTHALMOLOGICA, Issue 2010M VANTOMME Purpose To assess the range of waveform score in IOP measurements with ocular response analyzer (ORA, Reichert) in healthy subjects. Methods Prospective study including both eyes of healthy subjects with no ocular pathology or previous refractive surgery. The IOP measurements with ORA from both eyes were performed. The inclusion criteria of the measurements were solely based on good waveforms by an experienced clinician. The waveform score of three measurements were included for statistical analysis. Other parameters including age, central corneal thickness (CCT) and axis length were also analysed to evaluate possible correlations. Spearman correlation coefficient was used to assess the correlation. Results To date, both eyes of 42 healthy subjects are included (Mean age: 46.6 ± 14.3 yrs, Axial length: 23.7 ± 1.1, CCT: 554 ± 34 µm). The mean waveform scores from the first IOP measurement were 4.2±2.3 and for the 2de and 3th respectively 4.2±1.9 and 4.2±2.1 (not significantly different). The mean waveform score of 252 signals (both eyes and 3 measurements) was 4.2±2.1 and ranged from 0.3 to 9.6. Considering the best signal value per patient, the mean of all best signal values was 5.5±2.0 and it ranged from 1.9 to 9.5. The lowest 10% of all the best signal value was<3. Conclusion The waveform score is a new parameter indicating the reliability of each measurement signal. The best signal value indicates the best measurements of each session (Not the mean of the measurements). To date, our results show that the lower 10% percentile is <3. This could suggest that all the measurements with waveform score lower than 3 should be discarded. [source] Development of a new semi-quantitative non-invasive method for evaluating ventricular stroke workCLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, Issue 2 2009Mu-Hua Cheng Abstract Background and aim:, Ventricular stroke work (SW) is one of the best indices to evaluate ventricular function, however, the SW monitoring mainly depends on the invasive method with the artery catheter. In this paper, our aim is to develop a new semi-quantitative non-invasive method for evaluating ventricular SW. Methods:, The multiple gated cardiac blood pool imaging was done in 25 patients with coronary artery disease and 12 normal controls. A new parameter, the relative stroke work (RSW) of left ventricle, was calculated using an equation derived from the principle of hydrodynamics. The left ventricular SW was analyzed by stroke volume (SV) and mean arterial pressure. Ejected fraction (EF), peak ejected rate (PER) and peak filling rate (PFR) were gotten with the routine software in imaging device. Results:, The left ventricular RSW was linearly correlated with the SW. The RSW was related to the SV, EF, PER and PFR of the left ventricle. The RSW had regressive relation with SV and PER. The RSW in patients, same as SW, SV, EF, PFR and PER, was noticeably lower than that in normal controls, P<0·01. Conclusion:, The RSW is a potential and valuable clinical index for evaluation of the ventricular function. [source] Has repetitive transcranial magnetic stimulation (rTMS) treatment for depression improved?ACTA PSYCHIATRICA SCANDINAVICA, Issue 3 2007A systematic review, meta-analysis comparing the recent vs. the earlier rTMS studies Objective:, To investigate whether the recent repetitive transcranial magnetic stimulation (rTMS) studies on depression using new parameters of stimulation have shown improved clinical results. Method:, We performed a systematic review and a meta-analysis of the rTMS studies on depression published in the past 12 months comparing these results with an earlier meta-analysis that analyzed the results of the initial rTMS studies on depression. Results:, Using our inclusion criteria, we selected the meta-analysis of Martin [Br J Psychiatry (2003) Vol. 182, 480,491] that included 13 studies (324 patients) and five studies for the recent meta-analysis (274 patients). The pooled effect size (standardized mean difference between pretreatment vs. post-treatment) from the random effects model was ,0.76 (95% confidence interval, CI, ,1.01 to ,0.51). This result was significantly larger than that of the earlier meta-analysis (,0.35, 95% CI ,0.66 to ,0.04). Conclusion:, Our findings suggest that recent rTMS clinical trials have shown larger antidepressant effects when compared with the earlier studies. [source] Evaluation of the MODFLOW-2005 Conduit Flow ProcessGROUND WATER, Issue 4 2010Melissa E. Hill The recent development of the Conduit Flow Process (CFP) by the U.S. Geological Survey (USGS) provides hydrogeologic modelers with a new tool that incorporates the non-Darcian, multiporosity components of flow characteristic of karst aquifers. CFP introduces new parameters extending beyond those of traditional Darcian groundwater flow codes. We characterize a karst aquifer to collect data useful for evaluating this new tool at a test site in west-central Florida, where the spatial distribution and cross-sectional area of the conduit network are available. Specifically, we characterize: (1) the potential for Darcian/non-Darcian flow using estimates of specific discharge vs. observed hydraulic gradients, and (2) the temporal variation for the direction and magnitude of fluid exchange between the matrix and conduit network during extreme hydrologic events. We evaluate the performance of CFP Mode 1 using a site-scale dual-porosity model and compare its performance with a comparable laminar equivalent continuum model (ECM) using MODFLOW-2005. Based on our preliminary analyses, hydraulic conductivity coupled with conduit wall conductance improved the match between observed and simulated discharges by 12% to 40% over turbulent flow alone (less than 1%). [source] Hierarchical model of the population dynamics of hippocampal dentate granule cellsHIPPOCAMPUS, Issue 5 2002G.A. Chauvet Abstract A hierarchical modeling approach is used as the basis for a mathematical representation of the population activity of hippocampal dentate granule cells. Using neural field equations, the variation in time and space of dentate granule cell activity is derived from the summed synaptic potential and summed action potential responses of a population of granule cells evoked by monosynaptic excitatory input from entorhinal cortical afferents. In this formulation of the problem, we have considered a two-level hierarchy: the synapses of entorhinal cortical axons define the first level of organization, and dentate granule cells, which include these synapses, define the second, higher level of organization. The model is specified by two state field variables, for membrane potential and for synaptic efficacy, respectively, with both evolving according to different time scales. The two state field variables introduce new parameters, physiological and anatomical, which characterize the dentate from the point of view of neuronal and synaptic populations: (1) a set of geometrical constraints corresponding to the morphological properties of granule cells and anatomical characteristics of entorhinal-dentate connections; and (2) a set of neuronal parameters corresponding to physiological mechanisms. Assuming no interaction between granule cells, i.e., neither ephaptic nor synaptic coupling, the model is shown to be mathematically tractable and allows solution of the field equations leading to the determination of activity. This treatment leads to the definition of two state variables, volume of stimulated synapses and firing time, which describe observed activity. Numerical simulations are used to investigate the populational characterization of the dentate by individual parameters: (1) the relationship between the conditions of stimulation of active perforant path fibers, e.g., stimulating intensity, and activity in the granule cell layer; and (2) the influence of geometry on the generation of activity, i.e., the influence of neuron density and synaptic density-connectivity. As an example application of the model, the granule cell population spike is reconstructed and compared with experimental data. Hippocampus 2002;12:698,712. © 2002 Wiley-Liss, Inc. [source] Empirical models of UV total radiation and cloud effect studyINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 9 2010David Mateos Villán Abstract Several empirical models of hourly ultraviolet total radiation (UVT) have been proposed in this study. Measurements of UVT radiation, 290,385 nm, have been recorded at ground level from February 2001 to June 2008 in Valladolid, Spain (latitude 41°40,N, longitude 4°50,W and 840 m a.s.l.). The empirical models have emerged due to the lack of some radiometric variables in measuring stations. Hence, good forecasts of them can be obtained from usual measures in these stations. Therefore, some advantages of the empirical models are that they allow the estimation of past missing data in the database and the forecast of future ultraviolet solar availability. In this study, reported models in the bibliography have been assessed and recalibrated. New expressions have been proposed that allow obtaining hourly values of ultraviolet radiation from global radiation measures and parameters as clearness index and relative optical air mass. The accuracy of these models has been assessed through the following statistical indices: mean bias, mean-absolute bias and root-mean-square errors whose values are close to zero, below 7% and below 10%, respectively. Two new clear sky models have been used to evaluate two new parameters: ultraviolet and global cloud modification factors, which can help to understand the role of the clouds on solar radiation. The ultraviolet cloud modification factor depends on cloudiness in such a way that its value under overcast skies is half of the cloudless skies one. Exponential and potential fits are the best relationships between both cloud factors. Finally, these parameters have been used to build new UV empirical models which show low values of the statistical indices mentioned above. Copyright © 2009 Royal Meteorological Society [source] Quality counts: new parameters in blood cell countingINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 3 2009C. BRIGGS Summary Recently several parameters have been introduced to the complete blood count such as nucleated red blood cells, immature granulocytes; immature reticulocyte fraction, immature platelet fraction and red cell fragments as well as new parameters for detection of functional iron deficiency. Leucocyte positional parameters, which may diagnose specific diseases (e.g. differentiate between abnormal lymphocytes in leukaemia and viral conditions and may also detect malarial infection) are now available. At this time they are only used for research; however, generally such parameters later become reportable. One manufacturer's routine analyser allows measurement of cells by flow cytometry using monoclonal antibodies. Currently, there are no accredited external quality assessment schemes (EQAS) for these parameters. For a number of parameters, on some instruments, there is no internal quality control, which brings into question whether these parameters should be used for clinical decision making. Other more established parameters, such as mean platelet volume, red cell distribution width and the erythrocyte sedimentation rate do not have EQAS available. The UK National EQAS for General Haematology held a workshop earlier this year in 2008 to discuss these parameters. Participants were asked to provide a consensus opinion on which parameters are the most important for inclusion in future haematology EQAS. [source] Advances in powder diffraction pattern indexing: N-TREOR09JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5 2009Angela Altomare Powder pattern indexing can still be a challenge, despite the great recent advances in theoretical approaches, computer speed and experimental devices. More plausible unit cells, belonging to different crystal systems, are frequently found by the indexing programs, and recognition of the correct one may not be trivial. The task is, however, of extreme importance: in case of failure a lot of effort and computing time may be wasted. The classical figures of merit for estimating the unit-cell reliability {i.e.M20 [de Wolff (1968). J. Appl. Cryst.1, 108,113] and FN [Smith & Snyder (1979). J. Appl. Cryst.12, 60,65]} sometimes fail. For this reason, a new figure of merit has been introduced in N-TREOR09, the updated version of the indexing package N-TREOR [Altomare, Giacovazzo, Guagliardi, Moliterni, Rizzi & Werner (2000). J. Appl. Cryst. 33, 1180,1186], combining the information supplied by M20 with additional parameters such as the number of unindexed lines, the degree of overlap in the pattern (the so-called number of statistically independent observations), the symmetry deriving from the automatic evaluation of the extinction group, and the agreement between the calculated and observed profiles. The use of the new parameters requires a dramatic modification of the procedures used worldwide: in the approach presented here, extinction symbol and unit-cell determination are simultaneously estimated. N-TREOR09 benefits also from an improved indexing procedure in the triclinic system and has been integrated into EXPO2009, the updated version of EXPO2004 [Altomare, Caliandro, Camalli, Cuocci, Giacovazzo, Moliterni & Rizzi (2004). J. Appl. Cryst. 37, 1025,1028]. The application of the new procedure to a large set of test structures is described. [source] Hematopoietic progenitor cells (HPC) and immature reticulocytes evaluations in mobilization process: new parameters measured by conventional blood cell counterJOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 4 2006J.F.A. Noronha Abstract Monitoring the timing of leukapheresis in peripheral blood stem cells (PBSC) mobilization is an important clinical decision that requires an accurate analytical tool. The present study assessed hematopoietic progenitor cells (HPC) and immature reticulocyte fraction (IRF) counts provided by a routine automated blood counter as potential parameters for predicting the appropriate time for harvesting. The HPC and IRF values were compared with white blood cell (WBC) and CD34+ cell counts obtained by flow cytometry in 30 adult patients with hematological malignancies undergoing PBSC mobilization. It was observed that there was a significant correlation between HPC counts and CD34+ cells in peripheral blood counts (r=0.61, P=0.0003) and between the number of HPC and CD34+cells collected by leukapheresis (r=0.5733, P=0.0009). Comparing HPC, IRF, WBC, and CD34+ cells parameters as a sign of hematological recovery showed that the raise in immature reticulocytes counts preceded the increase of WBC (P=0.0002), HPC (P=0.0001), and CD34+ (P=0.0001) cells in peripheral blood counts. According to our results, HPC and IRF parameters may be integrated into clinical protocols to evaluate the timing of leukapheresis. IRF, as previously demonstrated in bone marrow transplantation, is the earliest sign of hematopoietic recovery in mobilization process. J. Clin. Lab. Anal. 20:149,153, 2006. © 2006 Wiley-Liss, Inc. [source] Parameterization of charge model 3 for AM1, PM3, BLYP, and B3LYPJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 11 2003Jason D. Thompson Abstract We have recently developed a new Class IV charge model for calculating partial atomic charges in molecules. The new model, called Charge Model 3 (CM3), was parameterized for calculations on molecules containing H, Li, C, N, O, F, Si, S, P, Cl, and Br by Hartree,Fock theory and by hybrid density functional theory (DFT) based on the modified Perdew,Wang density functional with several basis sets. In the present article we extend CM3 to semiempirical molecular orbital theory, in particular Austin Model 1 (AM1) and Parameterized Model 3 (PM3), and to the popular BLYP and B3LYP DFT and hybrid DFT methods, respectively. For the BLYP extension, we consider the 6-31G(d) basis set, and for the B3LYP extension, we consider three basis sets: 6-31G(d), 6-31+G(d), and MIDI!6D. We begin with the previous CM3 strategy, which involves 34 parameters for 30 pairs of elements. We then refine the model to improve the charges in compounds that contain N and O. This modification, involving two new parameters, leads to improved dipole moments for amides, bifunctional H, C, N, O compounds, aldehydes, ketones, esters, and carboxylic acids; the improvement for compounds not containing N results from obtaining more physical parameters for carbonyl groups when the OCN conjugation of amides is addressed in the parameterization. In addition, for the PM3 method, we added an additional parameter to improve dipole moments of compounds that contain bonds between C and N. This additional parameter leads to improved accuracy in the dipole moments of aromatic nitrogen heterocycles with five-membered rings. © 2003 Wiley Periodicals, Inc. J Comput Chem 24: 1291,1304, 2003 [source] ROLE OF TUBER DENSITY IN POTATO SLOUGHINGJOURNAL OF TEXTURE STUDIES, Issue 2 2006Í BLAHOVEC ABSTRACT A new CPEM method was developed and used to study the cooking curves of two potato varieties showing differences in texture and of one variety cultivated in four different regimes. The two main cooking curve stages (i.e., cooking and disintegration) can be described by simple linear equations, with density as an independent parameter. The parameters in the equation describing the cooking stage were reformulated to express directly the role of starch. The two new parameters obtained were weakly correlated and expressed separately cooking time sensitivity to starch content and the basic potato characteristic in relation to sloughing. Data obtained indicate only a minor role of starch content during the first part of cooking that is determined primarily by basic potato characteristics probably related to the cell wall properties. In the second stage of disintegration, starch content plays a more important role. [source] | |||||||||||||||||||||||||