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Selected AbstractsNutritional advice and treatment by dietitians to patients with amyotrophic lateral sclerosis/motor neurone disease: a survey of current practice in England, Wales, Northern Ireland and CanadaJOURNAL OF HUMAN NUTRITION & DIETETICS, Issue 1 2007A. Rio Abstract Background, The management of amyotrophic lateral sclerosis/motor neurone disease (ALS/MND) has shifted from an attitude of nihilism to treatments that prolong survival and offer hope. Nutrition is an integral component of ALS/MND care requiring coordination among acute and community multi-disciplinary teams (MDT). Evidence-based nutrition guidelines exist for this patient group but their use among dietitians is unknown. The aim of this study was to survey the knowledge, practice and guideline use of dietitians working in ALS/MND centres/clinics across England, Wales, Northern Ireland (EWNI) and Canada. Method, Dietetic contact details were obtained from the Motor Neurone Disease Association (MNDA) and the ALS Society of Canada (ALSSC) websites. Telephone interviews were conducted with 23 dietitians using a standardized questionnaire. Results, Multi-disciplinary team membership was high (78%). Only 22% dietitians had >4-years experience in ALS/MND care. Dietitians reported using body weight, percentage weight loss (PWL) and body mass index (BMI) to assess nutritional status. Equations used to estimate energy and protein requirements differed. Most frequent dietary advice was high calorie, texture modification and prescription nutritional supplements. Artificial nutrition and hydration (ANH) was discussed when patients developed dysphagia, energy intake was inadequate, weight loss of 10% or forced vital capacity (FVC) was reduced. A percutaneous endoscopic gastrostomy (PEG) service was available at all clinics/centres. Conclusion, Nutritional assessment techniques and dietary advice should be standardized. Dietetic collaboration at national and international level is recommended to reduce professional isolation. Training and support in ALS/MND nutrition should be made available as part of post-dietetic registration. Further dietetic research is required to stimulate nutritional care. [source] Symmetric Galerkin BEM for multi-connected bodiesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2001J. J. Pérez-Gavilán In this paper, it is shown that the symmetric Galerkin boundary element formulation cannot be used in its standard form for multiple connected bodies. This is because the traction integral equation used for boundaries with Neuman boundary condition give non-unique solutions. While this fact is well known from the classical theory of integral equations, the problem has not been fully addressed in the literature related to symmetric Galerkin formulations. In this paper, the problem is reviewed and a general way to deal with it is proposed. The details of the numerical implementation are discussed and an example is solved to demonstrate the effectiveness of the proposed solution. Copyright © 2001 John Wiley & Sons, Ltd. [source] Classification of renal disease status using estimated glomerular filtration rates in diabetesPRACTICAL DIABETES INTERNATIONAL (INCORPORATING CARDIABETES), Issue 8 2007How do the Cockcroft's & Gault's, the Modification of Diet in Renal Disease (MDRD) study equations compare? Abstract The need for the incorporation of estimated glomerular filtration rates (eGFR) in diabetes renal risk assessment is increasingly recognised but the choice of equation to use is not clear. We evaluated the differential impact of eGFR, using the Cockcroft's & Gault's (C&G) and the Modification of Diet in Renal Disease (MDRD) study equations, on the prevalence of various stages of chronic renal disease in our diabetes population. A cross sectional evaluation was conducted amongst 4548 individuals who attended our centre over an 18-month period. SPSS was utilised for statistical analysis. Of 4171 with complete data, the prevalence of individuals with eGFR >90, 90,60, 60,30 and <30ml/min/1.73m2 were 25%, 46%, 27% and 2% respectively using the C&G equation and 9%, 62%, 27% and 2% respectively using the MDRD equation. The two equations were fully concordant in their classification of eGFR rank in 65%; in 20% of the cohort, the equations were discordant but not at an arbitrary eGFR threshold of 60ml/min/1.73m2; while in 15% of the population the two equations were discordant even at the threshold of 60ml/min/1.73m2, the majority of whom had normal values of serum creatinine and urine albumin:creatinine ratio. In conclusion, the prevalence of various stages of chronic renal disease in our diabetes cohort differed depending on the eGFR equation used, potentially impacting on service provision. To aid clarity and uniformity of practice, there is a need for organisations to decide on a single equation of choice before recommending it to routine diabetes care providers. Copyright © 2007 John Wiley & Sons. [source] The influence of soil type and moisture on pupal survival of Bactrocera tryoni (Froggatt) (Diptera: Tephritidae)AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 1 2006Andrew D Hulthen Abstract, Larvae of the Queensland fruit fly, Bactrocera tryoni, pupate in the soil, but the influence of soil variables on B. tryoni pupal mortality is not known. For other tropical tephritid species, soil moisture has been identified as a major pupal mortality factor. In the laboratory, we tested the effects of soil moisture and soil type on pupal survival through a factorial experiment which used three soil types (loamy sand, loam, sandy clay) and seven soil moisture levels (0%, 10%, 25%, 50%, 75%, 90% and 100%). Minor, but significant, differences in pupal mortality were observed between the soil types, but the most significant factor affecting pupae was extremes of soil moisture. Eighty-five percent pupal mortality occurred at 0% soil moisture and 30% mortality at 100% soil moisture: very low levels of mortality occurred at all intermediate levels. We detected a significant interaction between soil type and moisture level but cannot explain it. In a follow-up experiment, we demonstrated that prepupal wandering larvae of B. tryoni could discriminate between different moisture levels, with significantly greater pupation in loam soil at 75% soil moisture than at either 0% or 100% soil moisture. Results are used to modify a pupal mortality/soil moisture equation used in a recently published DYMEX model of B. tryoni population dynamics. [source] Influence of reed stem density on foredune developmentEARTH SURFACE PROCESSES AND LANDFORMS, Issue 11 2001S. M. Arens Abstract Vegetation density on foredunes exerts an important control on aeolian sediment transport and deposition, and therefore on profile development. In a long-term monitoring field experiment, three plots were planted with regular grids of reed bundles in three different densities: 4, 2 and 1 bundles per m2. This study reports on the differences in profile development under the range of vegetation densities. Topographic profiles were measured between May 1996 and April 1997. Results indicate important differences in profile development for the three reed bundle densities: in the highest density plot a distinct, steep dune developed, while in the lowest density a more gradual and smooth sand ramp was deposited. When the stems had been completely buried, differences in profile evolution vanished. After a second planting of reed stems in January 1997 the process was repeated. In May 1997, all plots had gained a sand volume ranging from 11·5 to 12·3 m3 m,1, indicating that the sediment budget is relatively constant, regardless of the particular profile evolution. The field evidence is compared with simulations of profile development, generated by the foredune development model SAFE. The model successfully reproduces the overall profile development, but in general, the equations used for vegetation,transport interaction overestimate the effect of vegetation. This causes some deviations between field and model results. Several reasons for this are discussed. Based on the experiments reported here, recommendations are given for further research. Copyright © 2001 John Wiley & Sons, Ltd. [source] Compensation of actuator delay and dynamics for real-time hybrid structural simulationEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 1 2008M. Ahmadizadeh Abstract Compensation of delay and dynamic response of servo-hydraulic actuators is critical for stability and accuracy of hybrid experimental and numerical simulations of seismic response of structures. In this study, current procedures for compensation of actuator delay are examined and improved procedures are proposed to minimize experimental errors. The new procedures require little or no a priori information about the behavior of the test specimen or the input excitation. First, a simple approach is introduced for rapid online estimation of system delay and actuator command gain, thus capturing the variability of system response through a simulation. Second, an extrapolation procedure for delay compensation, based on the same kinematics equations used in numerical integration procedures is examined. Simulations using the proposed procedures indicate a reduction in high-frequency noise in force measurements that can minimize the excitation of high-frequency modes. To further verify the effectiveness of the compensation procedures, the artificial energy added to a hybrid simulation as a result of actuator tracking errors is measured and used for demonstrating the improved accuracy in the simulations. Copyright © 2007 John Wiley & Sons, Ltd. [source] Hydration of exercised Standardbred racehorses assessed noninvasively using multi-frequency bioelectrical impedance analysisEQUINE VETERINARY JOURNAL, Issue S36 2006A. WALLER Summary Reasons for performing study: In human and animal clinical practice, multi-frequency bioelectrical impedance analysis (MF-BIA) is increasingly used as a diagnostic tool to assess hydration of intra-and extracellular fluid compartments. Accurate determination of changes in hydration status within individuals over time has remained problematic due to the requirement for complete impedance-frequency relationships at the time points of interest. Objectives: To use MF-BIA in 13 Standardbred racehorses and 7 ,endurance' research horses to determine if MF-BIA could be used to track changes in total body water (TBW), intracellular fluid volume (ICFV) and extracellular fluid volume (ECFV) resulting from exercise. Methods: Jugular venous blood was sampled at rest and for 2,13 h following exercise. TBW, ECFV and plasma volume (PV) were measured at rest using indicator dilution techniques (D2O, thiocyanate and Evans Blue, respectively). TBW, ECFV, ICFV and PV were correlated to impedance measures and predictive equations used to determine hydration status from MF-BIA measures. Results: TBW loss continued throughout the recovery period, and was primarily borne by the ECF compartment at 90 min of recovery. Conclusions: MF-BIA predictions of compartmental hydration status were significantly correlated to measured/calculated decreases in these compartments. Potential relevance: Practical applications for MF-BIA in horses include monitoring of hydration status during transport and competition, assessment of body compostion, clinical health assessment and critical care management. [source] A dual mesh multigrid preconditioner for the efficient solution of hydraulically driven fracture problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 13 2005A. P. Peirce Abstract We present a novel multigrid (MG) procedure for the efficient solution of the large non-symmetric system of algebraic equations used to model the evolution of a hydraulically driven fracture in a multi-layered elastic medium. The governing equations involve a highly non-linear coupled system of integro-partial differential equations along with the fracture front free boundary problem. The conditioning of the algebraic equations typically degrades as O(N3). A number of characteristics of this problem present significant new challenges for designing an effective MG strategy. Large changes in the coefficients of the PDE are dealt with by taking the appropriate harmonic averages of the discrete coefficients. Coarse level Green's functions for multiple elastic layers are constructed using a single dual mesh and superposition. Coarse grids that are sub-sets of the finest grid are used to treat mixed variable problems associated with ,pinch points.' Localized approximations to the Jacobian at each MG level are used to devise efficient Gauss,Seidel smoothers and preferential line iterations are used to eliminate grid anisotropy caused by large aspect ratio elements. The performance of the MG preconditioner is demonstrated in a number of numerical experiments. Copyright © 2005 John Wiley & Sons, Ltd. [source] A confrontation of 1D and 2D RKDG numerical simulation of transitional flow at open-channel junctionINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 7 2009R. Ghostine Abstract In this study, a comparison between the 1D and 2D numerical simulation of transitional flow in open-channel networks is presented and completely described allowing for a full comprehension of the modeling water flow. For flow in an open-channel network, mutual effects exist among the channel branches joining at a junction. Therefore, for the 1D study, the whole system (branches and junction) cannot be treated individually. The 1D Saint Venant equations calculating the flow in the branches are then supplemented by various equations used at the junction: a discharge flow conservation equation between the branches arriving and leaving the junction, and a momentum or energy conservation equation. The disadvantages of the 1D study are that the equations used at the junction are of empirical nature due to certain parameters given by experimental results and moreover they often present a reduced field of validity. On the contrary, for the 2D study, the entire network is considered as a single unit and the flow in all the branches and junctions is solved simultaneously. Therefore, we simply apply the 2D Saint Venant equations, which are solved by a second-order Runge,Kutta discontinuous Galerkin method. Finally, the experimental results obtained by Hager are used to validate and to compare the two approaches 1D and 2D. Copyright © 2009 John Wiley & Sons, Ltd. [source] Injection/suction boundary conditions for fluid,structure interaction simulations in incompressible flowINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 7 2002G. Medic Abstract This paper presents the analysis of injection/suction boundary conditions in the context of the fluid,structure interactions simulation of the incompressible turbulent flow. First, the equations used in the modelling of the fluid and the structure are presented, as well as the numerical methods used in the corresponding solvers. Injection/suction boundary conditions are then presented with details of different implementation alternatives. Arbitrary Lagrangian,Eulerian (ALE) approach was also implemented in order to test the injection/suction boundary conditions. Numerical tests are performed where injection/suction boundary conditions are compared to ALE simulations. These tests include forced movement of the structure and two-degrees-of-freedom structure model simulations. Copyright © 2002 John Wiley & Sons, Ltd. [source] Conoscopic method for determination of main refractive indices and thickness of a uniaxial crystal cut out parallel to its optical axisJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 5 2009Leonas Dumitrascu This paper presents a simplified data acquisition and analysis technique for use in determining the main refractive indices and thickness of a uniaxial anisotropic layer cut out parallel to the optical axis, by processing the conoscopic interference figures obtained using a polarizing microscope equipped with a CCD camera. For negative uniaxial crystals, the equations used permit the calculation of the optical sign of the studied material so it is not necessary to insert a quartz wedge into the conoscopic beam. The technique can also be applied to the study of liquid crystal layers in a planar orientation. [source] On the general dynamic model of oceanic island biogeographyJOURNAL OF BIOGEOGRAPHY, Issue 6 2009Simone Fattorini Abstract Aim, To investigate the biological meaning of equations used to apply the general dynamic model (GDM) of oceanic island biogeography proposed by R. J. Whittaker, K. A. Triantis and R. J. Ladle. Location, Analyses are presented for 17 animal groups living on the Aeolian Islands, a volcanic archipelago in the central Mediterranean, near Sicily. Methods, In addition to the mathematical implementation of the GDM proposed by Whittaker, Triantis and Ladle, and termed here logATT2 (, where S is species number or any other diversity metric, t is island age, A is island area, and a, b, c and d are fitted parameters), a new implementation based on the Arrhenius equation of the species,area relationship (SAR) is investigated. The new model (termed powerATT2) is: . For logATT2 and powerATT2 models, equations were developed to calculate (1) the expected number of species at equilibrium (i.e. when the island has reached maturity) per unit area (Seq), and (2) the time required to obtain this value (teq). Whereas the intercept in the Gleason model (S = C + z log A) or the coefficient of the Arrhenius power model (S = CAz) of the SAR can be considered measures of the expected number of species per unit area, this is not the case for the parameter a of the ATT2 models. However, values of Seq can be used for this purpose. The index of ,colonization ability' (CAB), calculated as the ratio , may provide a measure of the mean number of species added per unit area per unit time. Results, Both ATT2 models fitted most of the data well, but the powerATT2 model was in most cases superior. Equilibrial values of species richness (Seq) varied from c. 3 species km,2 (reptiles) to 100 species km,2 (mites). The fitted curves for the powerATT2 model showed large variations in d, from 0.03 to 3. However, most groups had values of d around 0.2,0.4, as commonly observed for the z -values of SARs modelled by a power function. Equilibration times ranged from about 170,000 years to 400,000 years. Mites and springtails had very high values of CAB, thus adding many more species per unit area per unit time than others. Reptiles and phytophagous scarabs showed very low values, being the groups that added fewest species per unit area per unit time. Main conclusions, Values of equilibrial species richness per unit area are influenced by species biology (e.g. body size and ecological specialization). Theoretical and empirical evidence suggests that higher immigration rates should increase the z -values of the Arrhenius model. Thus, in the same archipelago, groups with larger z -values should be characterized by higher dispersal ability. Results obtained here for the parameter d conform to this prediction. [source] Application of the transformed Potts,Guy equation to in vivo human skin dataJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 9 2001William J. Roberts Abstract Data developed by Wenkers and Lippold for the flux of 10 nonsteroidal anti-inflammatory drugs from light mineral oil (MO) through human skin in vivo has been analyzed using the transformed Potts,Guy equation. The analysis shows that the flux is dependent not only on the solubility in MO (SMO), but also on the solubility in acidic water (SAQ). This dependence of flux on SAQ shows that the previously reported dependence of flux on SAQ from in vitro experiments using hairless mouse skin is not an artifact of the in vitro experiments but is due to a characteristic of the skin barrier. Further inspection of the equations used by Wenkers and Lippold in their analyses of their data shows that the equations are variations of the transformed Potts,Guy equation. © 2001 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 90:1318,1323, 2001 [source] Micromechanical analysis of silicon nitride: a comparative study by fracture mechanics and Raman microprobe spectroscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 9 2002Shigemi Tochino Raman microprobe spectroscopy was used to characterize in situ microstress fields which develop during fracture of a toughened silicon nitride (Si3N4) polycrystal. Maps of microscopic stress were collected in the neighborhood of a propagating crack both at zero and at critical loading conditions. Micromechanics results by Raman spectroscopy were analyzed and compared with conventional fracture mechanics assessments, such as the evaluation of rising R -curve behavior and crack opening displacement. Outcomes of these assessments illustrate that, despite the approximations involved in the piezo-spectroscopic equations used for calculating the microstress field from a local Raman shift, Raman microprobe spectroscopy is a viable method for semi-quantitative investigations of microfracture mechanisms in advanced ceramic materials. Copyright © 2002 John Wiley & Sons, Ltd. [source] Nested clade analysis statisticsMOLECULAR ECOLOGY RESOURCES, Issue 3 2006DAVID POSADA Abstract Nested clade analysis (NCA) is a flexible and powerful method to study the phylogeography of species and populations, implemented in the software geodis. Despite the popularity of this method, an explicit description of the exact equations used to compute the NCA statistics has never been published. Given the importance of the methodology and increased interest in exactly how it works, here we describe the exact equations implemented in the program geodis for the calculation of these statistics. [source] Relationship between the atomic pair distribution function and small-angle scattering: implications for modeling of nanoparticlesACTA CRYSTALLOGRAPHICA SECTION A, Issue 3 2009Christopher L. Farrow The relationship between the equations used in the atomic pair distribution function (PDF) method and those commonly used in small-angle-scattering (SAS) analyses is explicitly shown. The origin of the sloping baseline, ,4,r,0, in PDFs of bulk materials is identified as originating from the SAS intensity that is neglected in PDF measurements. The nonlinear baseline in nanoparticles has the same origin, and contains information about the shape and size of the nanoparticles. [source] On the Specification and Estimation of the Production Function for Cognitive Achievement*THE ECONOMIC JOURNAL, Issue 485 2003Petra E. Todd This paper considers methods for modelling the production function for cognitive achievement in a way that captures theoretical notions that child development is a cumulative process depending on the history of family and school inputs and on innate ability. It develops a general modelling framework that accommodates many of the estimating equations used in the literatures. It considers different ways of addressing data limitations, and it makes precise the identifying assumptions needed to justify alternative approaches. Commonly used specifications are shown to place restrictive assumptions on the production technology. Ways of testing modelling assumptions and of relaxing them are discussed. [source] | |||||||||||||||||||