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Parameters
Kinds of Parameters Terms modified by Parameters Selected AbstractsSTABILITY ANALYSIS OF A TRITROPHIC FOOD CHAIN MODEL WITH AN ADAPTIVE PARAMETER FOR THE PREDATORNATURAL RESOURCE MODELING, Issue 2 2009JEAN M. TCHUENCHE Abstract The study of three-species communities have become the focus of considerable attention, and because the studies of ecological communities start with their food web, we consider a tritrophic food chain model comprised of the prey, the predator, and the super-predator. The classical assumption of the domino effect is supplemented with an adaptive parameter for the predator (in the absence of prey). Thus, the model exhibits an equilibrium with the predator-top-predator steady state, which is a saddle point. Dynamical behaviors such as boundedness, existence of periodic orbits, persistence, as well as stability are analyzed. The long-term coexistence of the three interacting species is addressed, and the stability analysis of the model shows that the biologically most relevant equilibrium point is globally asymptotically stable whenever it satisfies a certain criterion. Practical implications are explored and related to real populations. [source] OPTIMAL AND ADAPTIVE SEMI-PARAMETRIC NARROWBAND AND BROADBAND AND MAXIMUM LIKELIHOOD ESTIMATION OF THE LONG-MEMORY PARAMETER FOR REAL EXCHANGE RATES,THE MANCHESTER SCHOOL, Issue 2 2005SAEED HERAVI The nature of the time series properties of real exchange rates remains a contentious issue primarily because of the implications for purchasing power parity. In particular are real exchange rates best characterized as stationary and non-persistent; nonstationary but non-persistent; or nonstationary and persistent? Most assessments of this issue use the I(0)/I(1) paradigm, which only allows the first and last of these options. In contrast, in the I(d) paradigm, d fractional, all three are possible, with the crucial parameter d determining the long-run properties of the process. This study includes estimation of d by three methods of semi-parametric estimation in the frequency domain, using both local and global (Fourier) frequency estimation, and maximum likelihood estimation of ARFIMA models in the time domain. We give a transparent assessment of the key selection parameters in each method, particularly estimation of the truncation parameters for the semi-parametric methods. Two other important developments are also included. We implement Tanaka's locally best invariant parametric tests based on maximum likelihood estimation of the long-memory parameter and include a recent extension of the Dickey,Fuller approach, referred to as fractional Dickey,Fuller (FD-F), to fractionally integrated series, which allows a much wider range of generating processes under the alternative hypothesis. With this more general approach, we find very little evidence of stationarity for 10 real exchange rates for developed countries and some very limited evidence of nonstationarity but non-persistence, and none of the FD-F tests leads to rejection of the null of a unit root. [source] Corrigendum: AN EVALUATION OF NON-ITERATIVE METHODS FOR ESTIMATING THE LINEAR-BY-LINEAR PARAMETER OF ORDINAL LOG-LINEAR MODELSAUSTRALIAN & NEW ZEALAND JOURNAL OF STATISTICS, Issue 2 2010Eric J. Beh No abstract is available for this article. [source] ESTIMATING A PARAMETER WHEN IT IS KNOWN THAT THE PARAMETER EXCEEDS A GIVEN VALUEAUSTRALIAN & NEW ZEALAND JOURNAL OF STATISTICS, Issue 4 2009Ian R. Gordon Summary In some statistical problems a degree of explicit, prior information is available about the value taken by the parameter of interest, , say, although the information is much less than would be needed to place a prior density on the parameter's distribution. Often the prior information takes the form of a simple bound, ,, > ,1' or ,, < ,1', where ,1 is determined by physical considerations or mathematical theory, such as positivity of a variance. A conventional approach to accommodating the requirement that,, > ,1,is to replace an estimator,,, of , by the maximum of,,and ,1. However, this technique is generally inadequate. For one thing, it does not respect the strictness of the inequality,, > ,1, which can be critical in interpreting results. For another, it produces an estimator that does not respond in a natural way to perturbations of the data. In this paper we suggest an alternative approach, in which bootstrap aggregation, or bagging, is used to overcome these difficulties. Bagging gives estimators that, when subjected to the constraint,, > ,1, strictly exceed ,1 except in extreme settings in which the empirical evidence strongly contradicts the constraint. Bagging also reduces estimator variability in the important case for which,,is close to ,1, and more generally produces estimators that respect the constraint in a smooth, realistic fashion. [source] AN EVALUATION OF NON-ITERATIVE METHODS FOR ESTIMATING THE LINEAR-BY-LINEAR PARAMETER OF ORDINAL LOG-LINEAR MODELSAUSTRALIAN & NEW ZEALAND JOURNAL OF STATISTICS, Issue 3 2009Eric J. Beh Summary Parameter estimation for association and log-linear models is an important aspect of the analysis of cross-classified categorical data. Classically, iterative procedures, including Newton's method and iterative scaling, have typically been used to calculate the maximum likelihood estimates of these parameters. An important special case occurs when the categorical variables are ordinal and this has received a considerable amount of attention for more than 20 years. This is because models for such cases involve the estimation of a parameter that quantifies the linear-by-linear association and is directly linked with the natural logarithm of the common odds ratio. The past five years has seen the development of non-iterative procedures for estimating the linear-by-linear parameter for ordinal log-linear models. Such procedures have been shown to lead to numerically equivalent estimates when compared with iterative, maximum likelihood estimates. Such procedures also enable the researcher to avoid some of the computational difficulties that commonly arise with iterative algorithms. This paper investigates and evaluates the performance of three non-iterative procedures for estimating this parameter by considering 14 contingency tables that have appeared in the statistical and allied literature. The estimation of the standard error of the association parameter is also considered. [source] MAXIMUM LIKELIHOOD ESTIMATION FOR A POISSON RATE PARAMETER WITH MISCLASSIFIED COUNTSAUSTRALIAN & NEW ZEALAND JOURNAL OF STATISTICS, Issue 2 2005James D. Stamey Summary This paper proposes a Poisson-based model that uses both error-free data and error-prone data subject to misclassification in the form of false-negative and false-positive counts. It derives maximum likelihood estimators (MLEs) for the Poisson rate parameter and the two misclassification parameters , the false-negative parameter and the false-positive parameter. It also derives expressions for the information matrix and the asymptotic variances of the MLE for the rate parameter, the MLE for the false-positive parameter, and the MLE for the false-negative parameter. Using these expressions the paper analyses the value of the fallible data. It studies characteristics of the new double-sampling rate estimator via a simulation experiment and applies the new MLE estimators and confidence intervals to a real dataset. [source] ABSENCE OF CORRELATION BETWEEN QRS DURATION AND ECHOGRAPHIC PARAMETERS OF VENTRICULAR DESYNCHRONIZATION.ECHOCARDIOGRAPHY, Issue 2 2004CAN WE STILL TRUST THE ELECTROCARDIOGRAPHIC CRITERIA? Background: Identification of the responder candidates for multisite pacing is still difficult and severe heart failure, dilated left ventricle with reduced ejection fraction, prolonged QRS with left bundle branch block (LBBB) are still considered the principal indicators of ventricular desynchronization. The aim of the study was to assess if echographic ventricular desynchronization parameters measured in patients with dilated cardiomyopathy and severe heart failure are correlated with the duration of the QRS on surface electrocardiogram. Methods: This study included 51 patients aged 58.8 ± 7.4 years with idiopathic DCM. The following parameters were measured: QRS duration; effective contraction time (ECT) measured as the interval between QRS onset and closure of aortic valve, interventricular delay (IVD) measured as the time between onset of aortic and pulmonary flow, left ventricular mechanical delay (LVD) as the time from maximal interventricular septum contraction and posterior wall contraction, posterior (P), lateral (L), and posterolateral (PL) wall delays, as the time from QRS onset to maximal wall contraction. Regional post-systolic contraction was defined in a given wall as the difference (contraction delay , ECT)> 50 ms. Results: 29 patients presented complete LBBB, 22 patients had QRS duration < 120 ms. 39 patients had a post-systolic contraction of the PL wall (32 patients of the L wall and 26 patients of the P wall). 16 patients with QRS duration <120 had a post-systolic contraction of the PL wall (as for the LBBB the rest of 39 patients). In 40 patients the sequence of regional ventricular contraction was: P-L-PL wall (16 patients with QRS < 120). LVD was > 100 ms in 36 patients (26 patients with LBBB and 10 with QRS < 120). 27 patients with LBBB and 6 with QRS < 120 ms presented IVD > 30 ms. There was no correlation between the QRS duration and the parameters listed above. Conclusions: In a population of patients with severe heart failure and dilated cardiomyopathy there is no correlation between the duration of the QRS and echocardiographic parameters of ventricular desynchronization. These results show that mechanical ventricular desynchronization can be observed in patients with a QRS duration < 120 ms. Further studies are needed to evaluate if this population could beneficiate of multisite pacing therapy. [source] EASY AND FLEXIBLE BAYESIAN INFERENCE OF QUANTITATIVE GENETIC PARAMETERSEVOLUTION, Issue 6 2009Patrik Waldmann There has been a tremendous advancement of Bayesian methodology in quantitative genetics and evolutionary biology. Still, there are relatively few publications that apply this methodology, probably because the availability of multipurpose and user-friendly software is somewhat limited. It is here described how only a few rows of code of the well-developed and very flexible Bayesian software WinBUGS (Lunn et al. 2000) can be used for inference of the additive polygenic variance and heritabilty in pedigrees of general design. The presented code is illustrated by application to an earlier published dataset of Scots pine. [source] EVOLUTIONARY POTENTIAL OF A LARGE MARINE VERTEBRATE: QUANTITATIVE GENETIC PARAMETERS IN A WILD POPULATIONEVOLUTION, Issue 4 2009Joseph D. DiBattista Estimating quantitative genetic parameters ideally takes place in natural populations, but relatively few studies have overcome the inherent logistical difficulties. For this reason, no estimates currently exist for the genetic basis of life-history traits in natural populations of large marine vertebrates. And yet such estimates are likely to be important given the exposure of this taxon to changing selection pressures, and the relevance of life-history traits to population productivity. We report such estimates from a long-term (1995,2007) study of lemon sharks (Negaprion brevirostris) conducted at Bimini, Bahamas. We obtained these estimates by genetically reconstructing a population pedigree (117 dams, 487 sires, and 1351 offspring) and then using an "animal model" approach to estimate quantitative genetic parameters. We find significant additive genetic (co)variance, and hence moderate heritability, for juvenile length and mass. We also find substantial maternal effects for these traits at age-0, but not age-1, confirming that genotype,phenotype interactions between mother and offspring are strongest at birth; although these effects could not be parsed into their genetic and nongenetic components. Our results suggest that human-imposed selection pressures (e.g., size-selective harvesting) might impose noteworthy evolutionary change even in large marine vertebrates. We therefore use our findings to explain how maternal effects may sometimes promote maladaptive juvenile traits, and how lemon sharks at different nursery sites may show "constrained local adaptation." We also show how single-generation pedigrees, and even simple marker-based regression methods, can provide accurate estimates of quantitative genetic parameters in at least some natural systems. [source] EFFECTS OF APPLICATION PARAMETERS AND ADJUVANTS ON THE FOLIAR SURVIVAL AND PERSISTENCE OF ENTOMOPATHOGENIC NEMATODE STEINERNEMA CARPOCAPSAE ALL STRAIN ON CABBAGESINSECT SCIENCE, Issue 2 2004Yong-ling Jin Abstract, Effects of the critical parameters (spray pressure, the distance between a sprayer and the sprayed plant, the concentration of infective juveniles (Us), volumes of the sprayed suspension of IJs, the temperature and humidity combinations) and the addition of various adjuvants on the survival and persistence of entomopathogenic nematode Steinernema carpocapsae All strain on leaf surfaces of the Chinese cabbage Brassica pekingensis were determined. The results showed that (1) The pressure of a sprayer had negative influence on the persistence of IJs on the leaf. (2) The numbers of the living IJs collected on the leaf significantly increased with the IJ dosages applied on the leaf when the dosage was over 2 000 IJs per mL. (3) More IJs (from 10.1 IJs/cm2 to 45.5 IJs/cm2) were collected on the leaf when more volumes of IJ suspension (from 3.3 mL to 19.8 mL) were sprayed. However, when the highest volume of IJ suspension was used, the IJ numbers collected did not increase. (4) In general, the survival of the IJs on the leaf decreased with the exposure time. (5) The formulation of IJs by adding xanthan gum, a sticker and detergent surfactant enhanced the survival and persistence of IJs. The number of living IJs on the leaf with 0.3 % of xanthan gum was 150 times higher than that of the IJs with water alone. IJ suspensions with different concentrations of glycerin and with 0.5 % molasses and 0.01 % detergent surfactant showed similar effects. [source] EFFECTS OF TEMPERATURE ON CERTAIN POPULATION PARAMETERS OF LIRIOMYZA SATIVAE BLAN-CHARD (DIPTERA: AGROMYZIDAE)INSECT SCIENCE, Issue 2 2000ZHANG Run-jie Abstract, Effects of temperature on population parameters and the intrinsic rate of natural increase of the leafminer, Liriomyza sativae Blanchard, were studied at constant temperatures, 15, 20, 25, 30 and 3593 80% RH and a photoperiod of 12:12 (L:D) in the laboratory with Phaseolus vulgaris as the host plant. Developmental time of the immature stage decreased from 38 d at 15C to lld at 3593 Regression equations relating temperature (t) to development rates (y) for egg, larval and pupal stages, were y = 1.7862t - 13.841, y = 1.162t - 4.946 and y= 0.634t - 5.146, respectively. Longevity of female adult decreased from 20 d at 15°C to 9 d with temperature up to 35C The most favorable temperature range for reproduction was 20°C - 30oC in which the fecundity ranged from 158 to 282 eggs per female. The lowest total mortality was 9% at 25oC and the highest was 49% at 35 93 High intrinsic rate of natural increase (rm) was 0.27 and high net reproductive rate (R0) was 116.8 at temperature range between 25 t and 30 t indicating that this range was optimal for population growth and that population density might increase 117 times per generation under this temperature condition. Mean generation time (T) and time for population to double (t) decreased as temperature increased, showing a negative linear trend with temperature. The relationship between finite rate of increase (A) and temperature, however, was a positive linear regression. [source] KINETICS AND HYDROLYSIS PARAMETERS OF TOTAL FRUCTOOLIGOSACCHARIDES OF ONION BULBS: EFFECTS OF TEMPERATURE REGIMES AND CULTIVARSJOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2007NOUREDDINE BENKEBLIA ABSTRACT This work studied the percentage of hydrolysis, observed hydrolysis rate constant (kobs), half-life time (t1/2) and kinetics of degradation of the total fructooligosaccharides (FOS) of three different onion bulb cultivars (Yellow Spanish, Red Amposta and Tenshin) kept during 6 months under three temperature regimes, 10, 15 and 20C. The percentage of hydrolysis of FOS was higher at 20C than at 10C and ranged from 47 to 58% at 10C, from 63 to 68% at 15C and from 74 to 83% at 20C. The kobs ranged from 27 × 10,3 to 36 × 10,3/week at 10C and from 41 × 10,3/week to 47 × 10,3/week at 15C, while at 20C, it was high and was about kobs 56 × 10,3/week.. The t1/2 decreased when temperature increased, and varied from 19.5 to 26.0 weeks at 10C, from 14.6 to 16.8 weeks at 15C and from 9.4 to 12.3 weeks at 20C, indicating that high degree of polymerization (DP) FOS have shorter lives than low DP FOS. Linear regression and kinetics of hydrolysis have shown that FOS hydrolysis is higher at 20C, with a coefficient of regression ranging between 0.87 and 0.99. Apparently, FOS hydrolysis is temperature independent, and storage time had more effect on the higher DP FOS than on the lower DP FOS. [source] ELECTRICAL CONDUCTIVITY AND KINETIC PARAMETERS OF RICE STARCHJOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2007E. MORALES SANCHEZ ABSTRACT In the present work, rice starch was studied by differential scanning calorimetry (DSC) and electrical conductivity as a function of temperature. The gelatinization temperature was calculated using both methods. Three stages of electrical conductivity were found. When the logarithm of conductivity was plotted versus temperature, the data have been well adjusted to the linear equation, indicating that a model for conductivity may be created using an Arrhenius-type expression to obtain kinetic parameters such as onset, peakset, endset temperatures and gelatinization energy (Eg). The conductivity Eg was calculated and compared to the enthalpy H calculated from the DSC data. It was found that Eg and enthalpy are similar processes. We conclude that electrical conductivity is an alternative method for the study of starch,water mixtures. PRACTICAL APPLICATIONS This research provides a new methodology to obtain kinetic parameters such as temperature of the beginning, medium and ending of gelatinizaiton, which are important for determining the cooking range needed to obtain desired characteristics in a processed starch-containing food. [source] INFLUENCE OF SAMPLE SIZE AND SHAPE ON TRANSPORT PARAMETERS DURING DRYING OF SHRINKING BODIESJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2007NAJMUR RAHMAN ABSTRACT An experimental investigation on the influence of sample size and shape on heat and mass transport parameters under natural convection air-drying is presented. Potato cylinders with length of 0.05 m and thicknesses of 0.005, 0.008, 0.010 and 0.016 m, and circular slices with diameter of 0.05 m and thickness of 0.01 m were dried in a laboratory scale hot-air cabinet dryer. Results indicate that each transport parameter exhibits a linear relationship with sample thickness. Convective heat and mass transfer coefficients (hcand hm) decreased whereas moisture diffusion coefficient (Deff) increased with increasing thickness. Considering no sample shrinkage effect in the parameter analysis, for the thickness range considered, the values of hcare found to be underestimated in the range of 29.0,30.6%, whereas those of hmand Deff are overestimated in the range of 33.7,38.0% and 75.9,128.1%, respectively. Using Levenberg,Marquardt algorithm for optimization, a correlation for Biot number for mass transfer (Bim) as a function of drying time and sample thickness is proposed. A close agreement was observed between dimensionless moisture contents predicted by this relation and those obtained from experiments for different sample thicknesses at drying air temperature of 60C. For the same thickness and drying conditions, circular slices caused an increase in each transport parameter significantly. [source] RADIO FREQUENCY (RF) HEATING OF STARCH SOLUTIONS UNDER CONTINUOUS FLOW CONDITIONS: EFFECT OF SYSTEM AND PRODUCT PARAMETERS ON TEMPERATURE CHANGE ACROSS THE APPLICATOR TUBEJOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2002G.B. AWUAH ABSTRACT Studies were conducted to evaluate the effect of system and product parameters on the temperature change (,T) across a 1.5 kW radio frequency heater operating at 27.12 MHz. Starch solutions (1 to 4% w/w) were used at three different flow rates (0.35, 0.5 and 1 L/min) and four power levels (672, 912, 1152 and 1392 W). The average heating rate of starch solutions varied from 6 to 19C/min depending on flow rate, concentration and power level. The corresponding residence time varied from 1.5 to 4.3 min. Central composite designs involving power (830 to 1234 W) and starch concentration (1 to 4% w/w) at 0.5 L/min were used to study the effects of salt, pH and sugar. As expected fluid flow rate, power level and salt concentration had significant impact (P ± 0.05) on temperature change (,T) across the applicator tube. Although the interaction effect of salt and concentration influenced ,T (P < 0.05), observed trends were not clear cut. Sugar and pH had no significant (P >0.05) influence on ,T due probably to their relatively lower conductivities. However, the interaction effect of sugar and starch concentration affected ,T. Correlations were developed for estimating ,T across the tube as a function of power level, concentration, pH, added salt and sugar. Finally, dimensionless correlations involving the generalized Reynolds, Prandtl, Grashof numbers, dimensionless power and loss-factor ratios were developed for estimating the temperature ratio (U) across the RF applicator. [source] ACIDIC ELECTROLYZED WATER PROPERTIES AS AFFECTED BY PROCESSING PARAMETERS AND THEIR RESPONSE SURFACE MODELSJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 1 2004GABRIEL O. I. EZEIKE Several studies of acidic electrolyzed (EO) water demonstrated the efficacy of EO water for inactivation of different foodborne pathogens and reported on the chemical species present in EO water. This study was conducted to investigate the effect of production parameters (voltage, NaCl concentration, flow rate, and temperature) on the properties of EO water and to model the complex reactions occurring during the generation of EO water. At 0.1% salt concentration, EO water was produced at 2, 10, and 28 V. However, due to high conductivity of the electrolyte at 0.5% salt concentration, the voltage applied across the cell was limited to 7 V. The electrolyte flow rate was set at 0.5, 2.5, and 4.5 L/mn. For pH and oxidation-reduction potential (ORP), NaCl concentration was the most significant factor followed by voltage, electrolyte flow rate and temperature, respectively. However, in the case of residual chlorine, flow rate was relatively more important than voltage. Response surface methodology yielded models to predict EO water properties as functions of the process parameters studied, with very high coefficients of determination (R2= 0.872 to 0.938). In general, the higher the NaCl concentration and voltage, the higher the ORP and residual chlorine of EO water. Increased electrolyte flow rate will produce EO water with lower ORP and residual chlorine due to the shorter residence time in the electrolytic cell. [source] INFLUENCE OF PLATE TEMPERATURE AND MODE OF REHYDRATION ON TEXTURAL PARAMETERS OF PRECOOKED FREEZE-DRIED BEEFJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2003ANA MARIA IRENE BARTOLOMEU AYROSA The effects of various plate temperatures and rehydration procedures in texture of precooked freeze-dried beef, were evaluated. Frozen precooked commercial beef was freeze-dried at 20, 40, 60 and 80C during 24 h. The rehydration procedure involved two main variables: distilled water at room-temperature and at 80C, for 30 min. The texture profile analysis was performed with a TA-XT2 Texture Analyzer (SMS) for freeze-dried rehydrated samples and compared to frozen precooked beef. The results showed that with a same drying period, the 60C plate temperature and rehydrated in distilled water at room-temperature resulted in a better product texture, in regards to texture parameters hardness and chewiness. [source] EFFECTS of SHUCKING METHOD ON OPENING, MEAT YIELD and SELECTED QUALITY PARAMETERS of WEST AFRICAN CLAM, GALATEA PARADOXA (BORN)JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 5 2000E.O. EKANEM Samples (n= 100) of freshly harvested clams (Galatea paradoxa Born) from the Cross River, Nigeria, were subjected after 24 h depurations to heat treatment (steam and water at 60, 70, 80, 90, 100C) for 1,6 min to evaluate the effects of level of heat treatment on opening, meat yield, sensory properties, proximate composition, pH and electrical conductivity (EC). Observations were also made on the effects of some chemical shucking aids (NaOH, NaHCO3, Na2CO3, NaCl) in 60C water on these parameters. Results showed that boiling water was most effective in opening the clams, with 100% shucking achieved in 1 min. Steam was least effective, requiring 6 min for 100% opening. Temperature significantly and strongly influenced meat yield (p<0.05;r=-0.92). pH (p<0.01; r=0.97), EC (p<0.05; r =0.65) and sensory properties (p<0.05). In general, shucking aids reduced opening time, significantly p<0.05) raised meat pH and EC, and with the exception of NaCl, insignificantly (P>0.05) improved yield. NaHCO3, and Na2CO3, which cut time for 100% opening from 5 min to 2 min were most effective. There were slight but significant (P <0.05) drops in meat moisture, crude protein and ash contents with increase in temperature (T). the model equations, pH = 4.69 + 0.021 T and % yield = 39.95,0.172 T were found to reliably predict meat pH and yield, with insignificant differences (P>0.05) between predicted and experimental values. [source] THE EFFECT OF EXTRUDED FLOUR AND FERMENTATION TIME ON SOME QUALITY PARAMETERS OF IDLIJOURNAL OF FOOD QUALITY, Issue 1 2000KULWINDER KAUR ABSTRACT The effects on idli characteristics of fermentation time and substituting rice with differing proportions of rice flour extrusion-cooked under different conditions were studied. The specific gravity, pH and viscosity of batter and idli characteristics such as expansion, compression force and sensory attributes were measured and described using regression to fit a response surface analysis. Fermentation time showed the most pronounced effect on specific gravity, pH and aqueous dispersion viscosity of batter and taste scores of idli. Substituting rice flour with extruded rice flour at different levels were observed to have significant effect on expansion and appearance scores of idlis. The textural scores and compression force was significantly affected by extrusion temperature. The formulation containing rice substituted by 30% extruded rice flour extruded at 175C and fermented for 24 h produced idlis with highest expansion and overall acceptability. [source] HYGIENIC PARAMETERS, TOXINS AND PATHOGEN OCCURRENCE IN RAW MILK CHEESESJOURNAL OF FOOD SAFETY, Issue 3 2002K. DE REU ABSTRACT In total, 71 samples of retail raw milk cheeses produced or imported in Belgium and samples of Belgian farmhouse cheeses were examined for cotiforms, ,-glucuronidase positive Escherichia coli, Escherichia coli O157, Staphylococcus aureus, Salmonella spp., Listeria spp. and Listeria monocytogenes. The presence of staphylococcal enterotoxins was investigated on samples with S. aureus counts higher than 103 cfu/g. The incidence of coliforms, ,-glucuronidase positive E. coli and S. aureus was higher in soft than in blue veined, semi-hard, hard and fresh cheeses. Four mold-ripened soft cheeses were positive for E. coli O157. One of the 4 cheeses was positive for verotoxin VT2. Staphylococcal enterotoxins were detected in 1 soft redsmear cheese, which was positive for L. monocytogenes. L. monocytogenes was also detected in one fresh cheese. Salmonella was not detected in any of the 71 raw milk cheeses. [source] RELATION OF DEMOGRAPHIC, CLINIC AND BIOCHEMICAL PARAMETERS TO PERITONITIS IN PERITONEAL DIALYSISJOURNAL OF RENAL CARE, Issue 1 2008Sevel Dogan RN SUMMARY The relation of various demographic, clinical and biochemical parameters of peritoneal dialysis patients with peritonitis and other infections was evaluated. The age, gender, peritoneal dialysis (PD) period, educational status, peritonitis, exit site score, serum albumin, C-reactive protein (CRP), and triglyceride levels at the beginning and the last visit were recorded. Mean age of 32 patients was 45.1 years; PD period was 13.1 months. Albumin level was inversely proportional to the frequency of peritonitis. Patients with peritonitis had albumin levels that were lower at the last visit, and were independent of the CRP values at the start of PD and during follow-up. Significant correlation was detected between females and exit site scores. There was significant correlation between educational status and peritonitis. Albumin level at first visit was a factor that reduced the likelihood of peritonitis, and low levels obtained during follow-up constituted a risk for peritonitis. It was also shown that peritonitis risk tended to decrease inversely with education level. [source] EFFECT OF VARIETAL DIFFERENCES AND POLISHING OF RICE ON QUALITY PARAMETERS OF IDLIJOURNAL OF SENSORY STUDIES, Issue 5 2005CHANDINI S. KUMAR ABSTRACT The effect of varietal differences and polishing of rice on quality parameters of "idli," an Indian fermented product, were studied. In addition, the functional properties of decorticated (whole and split) black gram (Phaseolus mungo Roxb.), were also determined. Two varieties of raw rice, "Jaya" and "Minilong," and one variety of parboiled rice "Ponni" with two degrees of polishing (high and low) were selected. Idlis were prepared following standard procedures. Variations were observed in water and fat absorption capacities of two black gram samples. Emulsification capacity ranged from 102 to 110 mL/100 g. Foam capacities at different pH range were similar, but foam stability differed as a function of time. The pH of the fermented batter was between 4.1 and 4.8. Rice with a lesser degree of polishing fermented better with higher batter volume and microbial count, lesser shear value and gave softer idlis. However, sensory analysis revealed that idlis prepared with low-polish rice scored significantly lower for appearance and color quality compared with products prepared with high-polish rice. Significant differences were observed in the quality of flavor of all products. It can be concluded that the quality characteristics of Idli were influenced by the variety of rice and the degree of polishing, but the two types of black gram used, whole and split, had no effect. [source] TEXTURE PROFILE ANALYSIS , HOW IMPORTANT ARE THE PARAMETERS?JOURNAL OF TEXTURE STUDIES, Issue 5 2010ANDREW J. ROSENTHAL ABSTRACT A starch-glycerol gel was subjected to a two-bite compression test using two sample-instrument geometries, various speeds of compression and strain levels, both with lubrication or not. Results were interpreted using the primary characteristic terminology previously defined in Texture Profile Analysis. Compression speeds from 0.1 to 10 m/s showed a logarithmic relationship with hardness, cohesiveness, corrected cohesiveness and adhesiveness. Gels survived compression to strains of 0.90 without failing, strain levels from 0.25 to 0.90 resulted in an exponential rise in hardness with increasing strain and linear reduction in corrected cohesiveness. Lubrication had no significant influence on any of the measured parameters and an application of force with different sample-instrument geometry revealed that parallel plates and plungers only had an influence on gel hardness. Caution is urged when researchers modify the test protocol from 75% deformation with parallel plates. A minimum crosshead speed of 2 mm/s is recommended. PRACTICAL APPLICATIONS Texture Profile Analysis has been widely applied to test solid and semisolid foods; however, some researchers deviate from the original test protocol. This article attempts to show how modifying the parameters in the test protocol can influence the apparent properties of the sample. [source] A NEW APPROACH TO CORRELATE TEXTURAL AND COOKING PARAMETERS WITH OPERATING CONDITIONS DURING DOUBLE-SIDED COOKING OF MEAT PATTIESJOURNAL OF TEXTURE STUDIES, Issue 5 2000SUSANA E. ZORRILLA Cooking and textural parameters during double-sided cooking of hamburger patties were correlated with volume-averaged temperature at the end of the cooking process and gap thickness between plates. Frozen patties were cooked in a clamshell grill set at different plate surface temperatures (177C; 191C; 204C; 218C), for different gap thicknesses (9.65 mm; 10.55 mm; 10.55 mm; 11.05 mm) for 120 s. A decrease in the gap thickness and an increase in the plate surface temperature resulted in an increase in the cooking loss values (24,36%) and in a decrease of press juice values (8,25%). The values of peak load (183,215 N), modulus (16,19 N/mm), work needed in shearing (2300,2800 Nmm), hardness (25,32 N), cohesiveness (0.76,0.83), and chewiness (107,152 Nmm) of the patties increased when the gap thickness decreased and the plate surface temperature increased. There was no effect of the variables studied on springiness. The correlation equations involving the operating variables and quality parameters obtained are simple and useful in developing optimal process conditions. [source] INFLUENCE OF UNIAXIAL COMPRESSION RATE ON RHEOLOGICAL PARAMETERS AND SENSORY TEXTURE PREDICTION OF COOKED POTATOESJOURNAL OF TEXTURE STUDIES, Issue 1 2000ANETTE KISTRUP THYBO ABSTRACT The effect of uniaxial compression rate (20,1000 mm/min) on the parameters: Stress (,ftrue), strain (,fHencky) and work to fracture (Wf), modulus of deformability (Ed), maximum slope before fracture (Emax) and work during 75% compression (Wtotal) was investigated for ten potato varieties. Multivariate data analysis was used to study the correlation between and within the sensory and nonsensory measurements by Principal Component Analysis (PCA) which showed ,ftrue, Emax, Wf, and Wtotal to explain the same type of information in the data, and ,fHencky versus Ed another type of information in the data. The deformation rate had a large effect on ,fHencky. Nine sensory texture attributes covering the mechanical, geometrical and moistness attributes were evaluated. Relationships between uniaxial compression data at various deformation rates and the sensory texture attributes were studied by Partial Least Squares Regression (PLSR). A minor effect of deformation rate on the correlation with the sensory texture properties was obtained. Mechanical properties were predicted to a higher extent than the geometrical attributes and moistness. The prediction of the mechanical, geometrical and moistness attributes increased largely by using uniaxial compression supplemented by chemical measures such as dry matter and pectin methylesterase, but here no relevant effect of deformation rate was obtained. [source] Modified TEI Index: A Promising Parameter in Essential Hypertension?ECHOCARDIOGRAPHY, Issue 4 2005Nurgül Keser M.D. Purpose: Modified TEI index is pointed to be more effective in the evaluation of global cardiac functions compared to systolic and diastolic measurements alone. We planned to determine its applicability in hypertension and relation with left ventricular mass index (LVMI). Methods: We studied 48 patients with mild/moderate hypertension and normal coronary angiograms. In total 22 patients (12 men, 10 women, mean age: 55 ± 6) with normal LVMI were studied in group I, 26 patients (12 men, 14 women, mean age: 57 ± 7) with increased LVMI in group II, and 20 patients (10 men, 10 women, mean age: 53 ± 7) with normal blood pressure as a control group. Standard 2D, Doppler, and mitral annulus pulse wave tissue Doppler were used for all measurements. Modified TEI index was calculated as diastolic time interval measured from end of Am wave to origin of Em (a,) minus systolic Sm duration (b,) divided by b(a,,b,/b,). Results: Modified TEI index was significantly higher in both groups than normal group and in group II than in group I. (Control group: 0.33 ± 0.05, group I: 0.51 ± 0.17, group II: 0.68 ± 0.16, P< 0.0001). Conclusion: Modified TEI index, a marker of left ventricular systolic and diastolic functions, is impaired in hypertensives before hypertrophy develops and impairment is more prominent in hypertrophy. Therefore, (1) modified TEI index in hypertensives is a safe, feasible, and sensitive index for evaluation of global ventricular functions. (2) Evaluation of hypertensives with this index periodically may guide interventions directed toward saving systolic and diastolic functions. (3) Modified TEI index is gaining importance as a complementary parameter to standard Doppler or in cases where standard Doppler has its limitations. [source] Influence of Point-Defect Reaction Kinetics on the Lattice Parameter of Ce0.8Gd0.2O1.9ADVANCED FUNCTIONAL MATERIALS, Issue 4 2009Anna Kossoy Abstract The kinetics of point-defect association/dissociation reactions in Ce0.8Gd0.2O1.9 and their influence on the crystal lattice parameter are investigated by monitoring thermally induced stress and strain in substrate- and self-supported thin films. It is found that, in the temperature range of 100,180,°C, the lattice parameter of the substrate-supported films and the lateral dimensions of annealed, self-supported films both exhibit a hysteretic behavior consistent with dissociation/association of oxygen vacancy,aliovalent dopant complexes. This leads to strong deviation from linear elastic behavior, denoted in the authors' previous work as the "chemical strain" effect. At room temperature, the equilibrium state of the point defects is reached within a few months. During this period, the lattice parameter of the substrate-supported films spontaneously increases, while the self-supported films are observed to transform from the flat to the buckled state, indicating that formation of the dopant,vacancy complex is associated with a volume increase. The unexpectedly slow kinetics of establishing the defect equilibrium at room temperature can explain the fact that, depending on the sample history, the "observable" lattice parameters of Ce0.8Gd0.2O1.9, as reported in the literature, may differ from one another by a few tenths of a percent. These findings strongly suggest that the lattice parameter of the materials with a large concentration of interacting point defects is a strong function of time and material preparation route. [source] The course of some bone remodelling plasma metabolites in healthy horses and in horses offered a calcium-deficient dietJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3-4 2003V. De Behr Summary An inquiry was carried out to assess the concentrations of plasma metabolites related to bone remodelling in 21 saddle horses of Warmblood breed aged 4,26 years, five draught horses of Ardennes breed aged 4,10 years, and 10 Ardennes foals aged 9,11 months. They were fed according to normal feeding practice in Belgium. The changes in some bone remodelling plasma metabolite concentrations were studied when an unbalanced diet was offered and later corrected for four Warmblood horses. Bone formation was evaluated by bone alkaline phosphatase (BALP), total alkaline phosphatase (TALP) and osteocalcin (bone gla-protein, OC). Bone resorption was assessed by hydroxyproline (HYP). Total calcium, ionized calcium, phosphorus (P) and 25-hydroxyvitamin D3 [25-(OH)D] concentrations were more or less constant. The comparison of four bone remodelling factors between the Ardennes and Warmblood horses showed higher concentrations in the Ardennes breed. Bone marker concentrations decreased according to age. The correction of the unbalanced Ca : P diet induced inconsistent effects at plasma level. The interpretation of the different bone parameters appeared to be difficult if not associated with other parameters such as a complete anamnesis and clinical examination of the animal in addition to dietary evaluation. Zusammenfassung Verlauf verschiedener Knochenmarker bei gesunden Pferden und bei Pferden, welche mit einer in Bezug auf Kalzium unausgewogenen Ration gefüttert wurden Eine Studie zur Erfassung der Konzentrationen von Knochenmarkern wurde bei 21 Warmblütern im Alter von 4 bis 26 Jahren, fünf Ardenner Kaltblütern im Alter von 4 bis 10 Jahren und 10 Ardenner Kaltblutfohlen im Alter von 9 bis 11 Monaten durchgeführt. Die Pferde wurden gemäss der normalen Fütterungpraxis in Belgien gefüttert. Der Verlauf der Knochenmarkerkonzentrationen wurde auch bei vier Pferden gemessen, die zunächst mit einer unausgewogenen Ration in Bezug auf Kalzium und dann mit einer korrigierenden Ration gefüttert wurden. Der Knochenaufbau wurde anhand der Aktivität der knochenspezifischen alkalischen Phosphatase (BALP), der totalen alkalischen Phosphatasen (TALP) und anhand des Osteocalcin (bone gla-proteine, OC) gemessen. Der Knochenabbau wurde anhand des Hydroxyprolins (HYP) gemessen. Die Konzentrationen des totalen Kalziums, ionisierten Kalziums, Phosphors (P), und 25-Hydroxyvitamin D3 [25(OH)D] waren unverändert. Beim Vergleich der vier gemessenen Knochenmakerkonzentrationen bei den Ardenner Kaltblütern mit den Warmblutpferden konnte gezeigt werden, dass die Kaltblüter deutlich höhere Konzentrationen hatten als die Warmblüter. Die Konzentrationen der Marker nahmen mit steigendem Alter der Pferde ab. Die Korrektur der unausgewogenen Ca:P Ration ergab nicht eindeutige Veränderungen der Plasmakonzentrationen der verschiedenen Marker. Die Interpretation der verschiedenen Knochenmarker erscheint schwierig, wenn nicht andere Parameter, wie eine komplette Anamnese und eine klinische Untersuchung, sowie eine Auswertung der Ration hinzugezogen werden. [source] Untersuchungen an wachsenden Schweinen zum Futterwert einer neuen Ackerbohnensorte (Vicia faba L.) bei Ergänzung mit DL -Methionin oder DL -Methionin-HydroxyanalogJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 1-2 2002HJ. ABEL Investigations in growing pigs on the feeding value of a new cultivar of field beans (Vicia faba L.) supplemented with DL -methionine or DL -methionine-hydroxyanalogue A basal control mixture of barley, soy bean meal and soy bean oil was replaced by 25% of the new field bean-cultivar `Divine' and the resulting two mixtures were supplemented with minerals, trace elements, vitamins and amino acids according to the ideal protein concept. The control diet was adjusted with DL -methionine (DL -Met), the field bean mixture either with DL -Met or DL -methionine-hydroxyanalogue (DL -MHA) assuming biological equivalence on a molar basis for both supplements. The three experimental diets were fed to growing pigs (35,40 kg bwt.). Spontaneous urine samples were analysed separately for determining parameters that characterize the acid-base status of the pigs. There were no significant differences between experimental groups in nutrient digestibilities. The level of bacterially fermentable substances was increased in the diets containing field beans. The field beans contained 14 mg ME/kg DM. There were no significant (p < 0,05) differences in N- and mineral-retentions (Ca, P, Na, K) between the treatments. The stronger alkalinity found in urine after feeding the field bean mixtures resulted from a higher electrolyte balance of the diet. Eine Kontrollration aus Gerste, Sojaschrot und Sojaöl wurde zu 25% durch Ackerbohnen der neugezüchteten Sorte `Divine' ersetzt und beide Mischungen mit Mineral- und Wirkstoffen sowie Aminosäuren ergänzt. Die Ergänzung mit Methionin erfolgte in der Kontrollmischung mit DL -Methionin, in der Ackerbohnenmischung mit DL -Methionin (DL -Met) oder DL -Methionin-Hydroxyanalog (DL -MHA) unter Zugrundelegung der molaren Wirkungsäquivalenz der beiden Supplemente. Die resultierenden drei Futtermischungen wurden in Stoffwechselversuchen an Schweine (35,40 kg LM) gefüttert. Separate Spontanharnproben wurden auf Parameter des Säure-Basen-Haushalts der Tiere untersucht. Zwischen den Versuchsgruppen traten keine signifikanten Unterschiede in den Nährstoffverdaulichkeiten auf. Die Gehalte an bakteriell fermentierbarer Substanz wurden durch Ackerbohnen erhöht. Der Gehalt der Ackerbohnen an umsetzbarer Energie lag bei 14 MJ ME/kg T. Die N- und Mineralstoffretentionen (Ca, P, Na, K) der Schweine unterschieden sich zwischen den Fütterungsgruppen nicht signifikant (p < 0,05). Die bei Ackerbohnenfütterung gesteigerte Harn-Alkalität ließ sich auf erhöhte kaliumbedingte Elektrolytbilanzen des Futters zurückführen. [source] Clinical effects of a new mouthrinse containing chlorhexidine, cetylpyridinium chloride and zinc-lactate on oral halitosisJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 4 2003A dual-center, double-blind placebo-controlled study Abstract Objectives:, The aim of this double-blind, parallel study was to test the clinical efficacy of a newly developed mouthrinse in the treatment of oral halitosis in patients without periodontitis. Material and methods:, Forty volunteers, recruited in two centers, participated in this study. Patients were selected on the basis of (1) halitosis of oral origin, (2) full-mouth organoleptic score>1, using an arbitrary 0,5 scale, (3) level of volatile sulfur compounds (VSC)>170 parts per billion (ppb) and (4) Winkel tongue coating index (WTCI)>4 (0,12). Intervention included gargling with a mouthrinse containing chlorhexidine (0.05%), cetylpyridinium chloride (0.05%) and zinc-lactate (0.14%) or with a placebo mouthrinse without active ingredients. At days 0 and 14 clinical variables were assessed in order of performance: (1) organoleptic assessments, (2) levels of VSC, and (3) WTCI. Results:, Treatment with the active mouthrinse resulted in a significant mean reduction in the organoleptic score from 2.8 to 1.5 (p<0.005). In the placebo group, no significant reduction in the mean organoleptic score occurred. Consequently, this resulted, after 2 weeks, in a greater change of the organoleptic scores in the test group in comparison to the placebo group (p<0.005). The mean VSC scores were reduced from 292 to 172 ppb in the test group (p<0.005), whereas no reduction was observed in the placebo group. At the 2-week examination, the mean change of the VSC scores in the test group was significantly greater than the mean change in the placebo group (p<0.005). Neither in the test nor in the placebo group a significant reduction in tongue coating was observed. Conclusions:, In conclusion, the tested mouthrinse is effective in the treatment of oral halitosis. Zusammenfassung Klinischer Effekt einer neuartigen Chlorhexidin, Cetylpyridiniumchlorid und Zinklaktat enthaltenden Mundspüllösung auf Mundgeruch. Eine bizentrische plazebokontrollierte Doppelblindstudie Zielsetzung: Untersuchung der klinischen Wirksamkeit einer neu entwickelten Mundspüllösung für die Behandlung von Mundgeruch bei Patienten, die keine Parodontitis haben, mittels einer parallelarmigen Doppelblindstudie. Material und Methoden: 40 Freiwillige, die an 2 Zentren rekrutiert wurden, nahmen an dieser Studie teil. Die Patienten wurden nach folgenden Kriterien ausgewählt: 1) Mundgeruch, 2) organoleptischer Wert der gesamten Mundhöhle > 1 auf einer arbiträren Skala von 0 bis 5, 3) Spiegel flüchtiger Schwefelverbindungen (VSC) > 170 parts per billion (ppb), 4) Winkel Zungenbelagsindex (WTCI) > 4 (0-12). Die Therapie umfasste Gurgeln mit einer Mundspüllösung, die Chlorhexidin (0,05%), Cetylpyridiniumchlorid (0,05%) und Zinklaktat (0.14%) enthielt oder mit einer Plazebospüllösung, die keine aktiven Bestandteile aufwies. Am Tag 0 und 14 wurden klinische Parameter in folgender Reihenfolge erhoben: 1) organoleptische Messungen, 2) VSC-Spiegel, 3) WTCI. Ergebnisse: Die Behandlung mit der aktiven Spüllösung resultierte in einer signifikanten mittleren Reduktion des organoleptischen Werts von 2,8 auf 1,5 (p<0,005), während in der Plazebogruppe keine signifikante Verringerung des mittleren organoleptischen Werts beobachtet wurde. Konsequenterweise ergab sich nach 2 Wochen in der Testgruppe eine stärkere Veränderung des organoleptischen Werts als in der Plazebogruppe (p<0,005). Der mittlere VSC-Wert wurde in der Testgruppe von 292 auf 172 ppb reduziert (p<0,005), während in der Plazebogruppe keine Veränderung auftrat. Nach 2 Wochen wurde in der Testgruppe eine signifikant stärkere Veränderung des VSC-Werts beobachtet als in der Kontrollgruppe (p<0,005). Weder in der Test- noch in der Plazebogruppe wurde eine signifikante Reduktion des Zungenbelags beobachtet. Schlussfolgerung: Die untersuchte Mundspüllösung ist wirksam zur Behandlung von Mundgeruch. Résumé Effets cliniques d'un nouveau bain de bouche contenant de la chlorhexidine, du chlorure de cetylpyridinium et du lactate de zinc sur l'halitose buccale. Une étude bi-centrique contrôlée par placebo en double aveugle. Objectifs: Le but de cette étude bi-centrique en double aveugle en parallèle était de tester l'efficacité clinique d'un bain de bouche récemment développé pour le traitement de l'halitose buccale sans parodontite. Matériel & Méthodes: 40 volontaires recrutés dans deux centres ont participéà cette étude. Les patients ont été sélectionnés sur les critères suivants : 1) halitose d'origine buccale, 2) score organoleptique de la bouche complète > 1, en utilisant une échelle arbitraire allant de 0 à 5, 3) un niveau de composés volatiles sulfurés (VSC) > 170 portions par billion (ppb) 4) un indice de recouvrement de la langue de Winkel (WTCI) > 4 (0,12). L'intervention comprenait un gargarisme avec un bain de bouche contenant de la chlorhexidine (0.05%), du chlorure de cetylpyridinium (0.05%) et du lactate de zinc (0.14%) ou avec un placebo sans ingrédients actifs. Au jours 0 et 14 les paramètres cliniques furent relevés pour l'ordre d'exécution 1) estimation organoleptique 2)niveaux de VSC, 3) WTCI. Résultats: le traitement avec le bain de bouche actif résultait en une réduction moyenne significative du score organoleptique de 2.8 à 1.5 (p < 0.005). Dans le groupe placebo, aucune réduction significative du score moyen organoleptique n'était par contre relevée. En consequence, ceci impliquait après 2 semaines un changement plus grand des scores organoleptiques dans le groupe test par rapport par rapport au groupe placebo (p < 0.005). Les scores moyens de VSC étaient réduits de 292 à 172 ppb dans le groupe test (p < 0.005), alors qu'aucune diminution n'était observée dans le groupe placebo. Lors de l'examen à 2 semaines, le changement moyen des scores de VSC dans le groupe test était significativement plus importants que le changement moyen dans le groupe placebo. (p < 0.005). Aucune réduction significative du recouvrement de la langue n'était par contre observée, ni dans le groupe test, ni dans le groupe placebo. Conclusions: En conclusion, Le bain de bouche testé est efficace pour le traitement de l'halitose. [source] | |||||||||||||||||||||||||||||||||||||