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Distribution Curves (distribution + curve)
Selected AbstractsFast computation evolutionary programming algorithm for the economic dispatch problemEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 1 2006P. Somasundaram Abstract This paper essentially aims to propose a new EP based algorithm for solving the ED problem. The ED problem is solved using EP with system lambda as decision variable and power mismatch as fitness function. The algorithm is made fast through judicious modifications in initialization of the parent population, offspring generation and selection of the normal distribution curve. The proposed modifications reduce the search region progressively and generate only effective offsprings. The proposed algorithm is tested on a number of sample systems with quadratic cost function and also on a 10-unit system with piecewise quadratic cost function. The computational results reveal that the proposed algorithm has an excellent convergence characteristic and is superior to other EP based methods in many respects. Copyright © 2005 John Wiley & Sons, Ltd. [source] Intraocular pressure and associated factors in a Central Indian population.ACTA OPHTHALMOLOGICA, Issue 2009Medical Study, The Central India Eye Purpose To evaluate the intraocular pressure (IOP) and its associated factors in the adult population of rural India. . Methods The Central India Eye and Medical Study is a population-based study performed in a rural region close to Nagpur in Central India. It included 4711 subjects (aged 30+ years) out of 5885 eligible subjects (response rate: 80.1%). The participants underwent a detailed ophthalmic and medical examination. This study was focused on the IOP. Results Out of the 4711 subjects (9422 eyes), IOP measurements were available for 9338 (99.1%) eyes of 4686 (99.5%) subjects. The mean IOP was 13.6±3.4 mm Hg (median: 14 mm Hg; range: 2,56 mm Hg). Assuming a Gaussian distribution curve, the normal range of IOP, defined as mean ± two standard deviations, was from 6.8 mm Hg to 20.4 mm Hg. In multivariate analysis, IOP was significantly associated with the systemic parameters of higher diastolic blood pressure (P<0.001), higher pulse rate (P=0.004), and higher body mass index (P=0.007); the socioeconomic parameters of higher level of education (P=0.004), higher cast (P=0.002), and no livestock ownership (P=0.01); and the ocular parameters of higher corneal refractive power (P<0.001), lower central corneal thickness (P=0.002) and higher myopic refractive error (P=0.002). Conclusion The normal range of IOP was from 7 mm Hg to 20 mm Hg. Determinants of IOP were higher diastolic blood pressure, higher pulse rate, higher body mass index, higher level of education, higher cast, higher corneal refractive power, lower central corneal thickness and higher myopic refractive error. [source] Downstream variation in bed sediment size along the East Carpathian rivers: evidence of the role of sediment sourcesEARTH SURFACE PROCESSES AND LANDFORMS, Issue 5 2008Maria R, doane Abstract Taking as an example six main rivers that drain the western flank of the Eastern Carpathians, a conceptual model has been developed, according to which fluvial bed sediment bimodality can be explained by the overlapping of two grain size distribution curves of different origins. Thus, for Carpathian tributaries of the Siret, coarse gravel joins an unimodal distribution presenting a right skewness with enhanced downstream fining. The source of the coarse material distributions is autohtonous (by abrasion and hydraulic sorting mechanisms). A second distribution with a sandy mode is, in general, skewed to the left. The source of the second distribution is allohtonous (the quantity of sand that reaches the river-bed through the erosion of the hillslope basin terrains). The intersection of the two distributions occurs in the area of the 0·5,8 mm fractions, where, in fact, the right skewness (for gravel) and left skewness (for sand) histogram tails meet. This also explains the lack of particles in the 0·5,8 mm interval. For rivers where fine sediment sources are low, the 0·5,8 mm fractions have a higher proportion than the fractions under 1 mm. For the Siret River itself, bed sediment bimodality is greatly enhanced due to the fact that the second mode is more than 25% of the full sample. As opposed to its tributaries, the source of the first mode, of gravel, is allohtonous to the Siret river, generated by the massive input of coarse sediment through the Carpathian tributaries, while the second mode, of the sands, is local. In this case we can also observe that the two distributions of particles of different origins overlap in the 0·5,8 mm fraction domain, creating the illusion of ,particle lack' in the fluvial bed sediments. Copyright © 2007 John Wiley & Sons, Ltd. [source] Addiction as excessive appetiteADDICTION, Issue 1 2001Jim Orford The excessive appetite model of addiction is summarized. The paper begins by considering the forms of excessive appetite which a comprehensive model should account for: principally, excessive drinking, smoking, gambling, eating, sex and a diverse range of drugs including at least heroin, cocaine and cannabis. The model rests, therefore, upon a broader concept of what constitutes addiction than the traditional, more restricted, and arguably misleading definition. The core elements of the model include: very skewed consumption distribution curves; restraint, control or deterrence; positive incentive learning mechanisms which highlight varied forms of rapid emotional change as rewards, and wide cue conditioning; complex memory schemata; secondary, acquired emotional regulation cycles, of which 'chasing', 'the abstinence violation effect' and neuroadaptation are examples; and the consequences of conflict. These primary and secondary processes, occurring within diverse sociocultural contexts, are sufficient to account for the development of a strong attachment to an appetitive activity, such that self-control is diminished, and behaviour may appear to be disease-like. Giving up excess is a natural consequence of conflict arising from strong and troublesome appetite. There is much supportive evidence that change occurs outside expert treatment, and that when it occurs within treatment the change processes are more basic and universal than those espoused by fashionable expert theories. [source] Pyridoxal 5,-phoshate Schiff base in Citrobacter freundii tyrosinephenol-lyaseFEBS JOURNAL, Issue 6 2000Ionic, tautomeric equilibria Spectral properties of the internal Schiff base in tyrosine phenol-lyase have been investigated in the presence of an activating cation K+ and a cation-inhibitor Na+. The holoenzyme absorption spectra in the pH range 6.5,8.7 were recorded in the presence of K+. No apparent pKa value of the coenzyme chromophore was found in this pH range, indicating that the internal Schiff base does not change its ionic form on going from pH 6.5 to 8.7. To determine the ionic state and tautomeric composition of the Schiff base in tyrosine phenol-lyase, the absorption and circular dichroism spectra were analyzed using lognormal distribution curves. The predominant form of the internal Schiff base is that with protonated pyridinium and aldimine nitrogen atoms and deprotonated 3,-hydroxy group, i.e. the ketoenamine. This form is in prototropic equilibrium with its enolimine tautomer. The internal aldimine ionic form is changed upon replacement of K+ with Na+. This replacement leads to a significant decrease in the pKa value of pyridinium nitrogen of the pyridoxal- P. [source] Aquatic risks of pesticides, ecological protection goals, and common aims in european union legislationINTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2006Theo CM Brock Abstract This discussion paper presents a framework for spatiotemporal differentiation in ecological protection goals to assess the risks of pesticides in surface waters. It also provides a proposal to harmonize the different scientific approaches for ecotoxicological effect assessment adopted in guidance documents that support different legislative directives in the European Union (Water Framework Directive and Uniform Principles). Decision schemes to derive maximum permissible concentrations in surface water are presented. These schemes are based on approaches recommended in regulatory guidance documents and are scientifically underpinned by critical review papers concerning the impact of pesticides on freshwater organisms and communities. Special attention is given to the approaches based on standard test species, species sensitivity distribution curves, and model ecosystem experiments. The decision schemes presented here may play a role in the "acceptability" debate and can be used as options in the process of communication between risk assessors and risk managers as well as between these risk experts and other stakeholders. [source] Urinary tract cancer screening through analysis of urinary red blood cell volume distributionINTERNATIONAL JOURNAL OF UROLOGY, Issue 7 2000Mamoru Wakui Abstract Background: Hematuria is differentiated between glomerular and urinary tract origins on the basis of urinary red cell morphology. We used this distinction in a program of mass screening for urinary tract cancer to achieve cost-effective and safe hematuria screening. Methods: Of a total of 21 372 adults (mean age 52.3 years; range 20,79 years) participating in a health screening, 912 (4.3%) had a positive dipstick for hematuria and were enrolled in the present study. Urinary red cell volume distribution curves (RDC), the simplest method of assessing urinary red cell morphology, were calculated and subjects were divided into two groups based on their RDC patterns. Group I subjects had a normocytic or mixed pattern and they were immediately investigated for urinary tract malignancy because of the associated risk for urological disease. Group II subjects had a microcytic pattern and, therefore, were judged to be at a low risk of urologic malignancy and were followed up 3 years later without urologic investigations. Results: Among the 38 subjects in group I (4% of all dipstick-positive subjects), one case of bladder cancer was detected. In the remaining 37 patients, 15 cases of benign diseases were discovered. Group II was composed of 869 subjects (96%). The inquiry into their health status conducted 3 years later revealed that 831 (95.6%) were healthy and, of these, 13 had experienced gross hematuria during the period but urological malignancies were ruled out by their urologists, two (0.2%) had died of diseases other than urological cancer and 36 (4.1%) were lost to follow-up. With our method, total costs have been reduced by 93.8% against a conventional setting of a full evaluation for all cases of hematuria. Conclusions: Microcytic hematuria, accounting for 96% of asymptomatic microhematuria cases in the present study, was not associated with a risk for urinary tract malignancy. Compared with conventional hematuria screening with a complete work-up of all cases of hematuria, investigating only subjects with mixed or normocytic RDC patterns was safe and cost effective. [source] Syntheses of cyclic polycarbonates by the direct phosgenation of bisphenol M,JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 6 2005Hans R. Kricheldorf Abstract Bisphenol M was subjected to interfacial polycondensations in an NaOH/CH2Cl2 system with triethylamine as a catalyst. Regardless of the catalyst concentration, similar molecular weights were obtained, and matrix-assisted laser desorption/ionization time-of-flight mass spectra exclusively displayed mass peaks of cycles (detectable up to 15,000 Da). With triethyl benzyl ammonium chloride as a catalyst, linear chains became the main products, but the contents of the cycles and the molecular weights strongly increased with higher catalyst/bisphenol ratios. When the pseudo-high-dilution method was applied, both diphosgene and triphosgene yielded cyclic polycarbonates of low or moderate molecular weights. Size exclusion chromatography measurements, evaluated with the triple-detection method, yielded bimodal mass distribution curves with polydispersities of 5,12. Furthermore, a Mark,Houwink equation was elaborated, and it indicated that the hydrodynamic volume of poly(bisphenol M carbonate) was quite similar to that of poly(bisphenol A carbonate)s with similar concentrations of cyclic species. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1248,1254, 2005 [source] Psychometric performance and clinical meaningfulness of the Patient Assessment of Constipation , Quality of Life questionnaire in prucalopride (RESOLOR®) trials for chronic constipationNEUROGASTROENTEROLOGY & MOTILITY, Issue 2 2010D. Dubois Abstract Background, The Patient Assessment of Constipation,Quality of Life (PAC-QOL) is a self-reported questionnaire measuring health-related quality of life (HRQL) of constipated patients and was used as secondary endpoint in three identical double-blind, randomized, placebo-controlled Phase III clinical trials. These 12-week trials in subjects with severe chronic constipation evaluated the effects of prucalopride, a selective 5-HT4 agonist given orally once daily. Methods, To consolidate the main treatment effect results observed in the prucalopride trial populations, analyses were undertaken on the pooled data of the three trials to confirm the psychometric properties of the PAC-QOL and to provide guidance for the interpretation of the clinical significance of its scores. Key Results, The evaluation of the psychometric properties confirmed the PAC-QOL reliability, validity and responsiveness to measure the impact of chronic constipation symptoms on HRQL in the prucalopride trials. The 1-point improvement in PAC-QOL scores used as target response level for the main treatment effect analyses was validated as a relevant definition of response for treatment group comparisons. Cumulative distribution curves, drawn for each treatment group to provide more complete information on treatment effects than single minimal important difference point estimates, demonstrated consistent superior effects of prucalopride over placebo on all PAC-QOL scores. Conclusions & Inferences, The PAC-QOL questionnaire is a useful measurement tool to assess, from a patient perspective, the potential therapeutic value of chronic constipation treatments in clinical trials and, by directly reflecting the patient's own perspective on constipation and its treatment, eventually also for informing daily medical practice. [source] Preparation of extruded melt-mixed polypropylene/montmorillonite nanocomposites with inline monitoringPOLYMER ENGINEERING & SCIENCE, Issue 3 2010Marcelo K. Bertolino This article advances the use of an inline optical detector to monitor the disaggregation of the montmorillonite (MMT) clay tactoids during the preparation of polypropylene (PP)/MMT nanocomposites via polymer melt compounding. During the exfoliation of the tactoids their size are reduced below the minimum particle size to produce light extinction and so, the signal of the inline detector reduces as the nanosize composite is formed. The measurement is done at the transient state with the MMT clay added as a pulse with constant weight into the PP extrusion melt flow and followed by the optical detector. The data comes out as the common residence time distribution curves having its maximum intensity related to the tactoids average particle size, keeping all other variables constants. The light extinction was measured for composites with different clays (Cloisite® 15A, 30B, Na+, and Sintered 20A) using the same PP grafted with maleic anhydride compatibilizer. The dissaglomeration/exfoliation efficiency increases as: ,,Sintered 20A'' < ,,Na+ clay'' < ,,organo-modified clay'' < ,,organo-modified clay + compatibilizer''. The best result is obtained using Cloisite® 15A and Cloisite® 20A following the expected reduction of the particle size obtained during a nanocomposite melt processing. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers [source] An optical device to measure in-line residence time distribution curves during extrusionPOLYMER ENGINEERING & SCIENCE, Issue 1 2002Tomás Jeferson A. Mélo This paper proposes a setup for in-line measurement of residence time distribution (RTD) curves during extrusion. The detection system is composed of a slit die with transparent borosilicate glass windows fixed at the extruder exit, an optical arrangement with an incandescent light microbulb with fixed luminescence, and a Light Dependent Resistor (LDR) photocell of CdS. As the tracer passes through the light path, the reduction in the transmitted light intensity is followed by changes in the voltage induced by the photocell to an electric circuit. The signal is collected by an external interface and sent to a computer. Software acquires the data, does all calculations, and presents all curves and calculated variables to the monitor. The validation of the system was done by checking for data reproducibility and linearity with tracer concentration. The response of the LDR sensor with respect to the concentration of the tracer was calibrated using a set of slight dark film, obtaining a logarithmic relationship. Thus the signal enhances any disturbance, if present, particularly in the tail-region of the curves. Measurements were taken from a Werner-Pfleiderer ZSK 30 twin-screw extruder equipped with K-Tron gravimetric feeders operating with various screw speeds, feeding rates and screw configurations. In this last case, the presence of kneading elements was taken into account. [source] X-ray study and structure simulation of amorphous tungsten oxideACTA CRYSTALLOGRAPHICA SECTION B, Issue 4 2002L. A. Lugovskaya In this work, X-ray studies of the amorphous oxide films obtained by thermal evaporation of WO3 powder in a vacuum and by anodic oxidation were carried out. X-ray diffraction patterns were obtained in the symmetric reflection geometry on a DRON-4 diffractometer (Mo K, radiation, LiF monochromator) in automatic mode. Molecular dynamics simulation of amorphous tungsten oxide atomic configurations has been carried out in the micro-canonical ensemble (NVE) for N,=,208 atoms and N,=,624 atoms, in a cubic cell, using pairwise Born,Mayer interaction potentials and periodic boundary conditions. One of the purposes of the present work is to analyze the influence of the parameters and the cutoff of the interaction potentials on the interatomic distances. The values obtained in the molecular dynamics simulation for the pair functions D(r) are compared with the experimental data for amorphous oxides in order to choose the most convenient aforesaid values. The values of the average interatomic distances and the coordination numbers obtained by both methods are also compared. The result shows that the tungsten subsystem can be well reproduced using the potential cutoff radius of about 4,Å, but the oxygen subsystem can be well reproduced when the cutoff of the potential for the W,O pairs is equal to 2.8,Å. The configuration built during the molecular dynamics experiment consists of distorted octahedra. These octahedra form chains, as in the WO3 phases of type ReO3, and hexagonal rings, of the same type as in the WO3(1/3)H2O phase, when we extract (1/3)O at every WO3 unit. The pair function D(r) and scattering intensity I(s) distribution curves calculated for simulation configurations show a satisfactory agreement with experiment. [source] Birth weight charts for gestational age in 63 620 healthy infants born in Peruvian public hospitals at low and at high altitudeACTA PAEDIATRICA, Issue 3 2009Gustavo F Gonzales Abstract Aim: To construct distribution curves for birth weight, length and head circumference using a large sample of infants born at low (150 m) and high (3000,4400 m) altitude. Methods: Cross-sectional analysis of a perinatal database. All live singleton deliveries from public hospitals during 2001,2006 (gestational age from 26 to 42 weeks) with no history of perinatal deaths or smoking and no current obstetric complications (n = 63 620) were included. Fractional polynomial regression models were used to smooth curves for each gestational age. Results: Mean and median birth weight differences between those born at low and high altitudes reached statistical significance after 35 and 33 weeks, respectively. Values of the 10th percentile were higher at low altitude from 36 weeks, whereas values at the 90th percentile were different from 34 weeks. In the Peruvian growth curves, birth weight was greater at each gestational age than in the curves derived by Lubchenco. Conclusion: Altitude affects growth patterns; these growth standards will provide useful references for the care of the newborn in highland populations. In addition, the data have implications for the antepartum management of pregnant patients undergoing sonographic evaluation of fetal weight in whom new definitions of what represents small or large for gestational age in utero can result in differences in time or mode of delivery. [source] | |||||||||||||||||||