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FD
Kinds of FD Terms modified by FD Selected AbstractsA young woman with visual hallucinations, delusions of persecution and a history of performing arson with possible three-generation Fahr diseaseACTA PSYCHIATRICA SCANDINAVICA, Issue 1 2010M. Shirahama Objective:, Fahr disease (FD) is a rare neurological and psychiatric disorder. The disease is classified by intracranial calcification of the basal ganglia with the globus pallidus region being particularly affected. We examined a young woman with visual hallucinations, delusions of persecution and a history of performing arson with possible third-generation FD. Method:, Case report of third-generation FD. Results:, A 23-year-old woman was arrested for two arsons: i) The patient exhibited progressive psychotic symptoms, including visual hallucinations, delusion of injury, irritability, lability of mood, mental retardation and visual disorders and ii) Computed tomography (CT) imaging demonstrated bilateral calcifications of the basal ganglia (globus pallidus) in the patient, her mother and her grandmother. Conclusion:, We found a family with a three-generation history of FD who exhibited calcification in the brain and mental retardation. Compared to her mother, the patient described here displayed anticipation of disease onset. [source] Disentangling biodiversity effects on ecosystem functioning: deriving solutions to a seemingly insurmountable problemECOLOGY LETTERS, Issue 6 2003Shahid Naeem Abstract Experimental investigations of the relationship between biodiversity and ecosystem functioning (BEF) directly manipulate diversity then monitor ecosystem response to the manipulation. While these studies have generally confirmed the importance of biodiversity to the functioning of ecosystems, their broader significance has been difficult to interpret. The main reasons for this difficulty concern the small scales of the experiment, a bias towards plants and grasslands, and most importantly a general lack of clarity in terms of what attributes of functional diversity (FD) were actually manipulated. We review how functional traits, functional groups, and the relationship between functional and taxonomic diversity have been used in current BEF research. Several points emerged from our review. First, it is critical to distinguish between response and effect functional traits when quantifying or manipulating FD. Second, although it is widely done, using trophic position as a functional group designator does not fit the effect-response trait division needed in BEF research. Third, determining a general relationship between taxonomic and FD is neither necessary nor desirable in BEF research. Fourth, fundamental principles in community and biogeographical ecology that have been largely ignored in BEF research could serve to dramatically improve the scope and predictive capabilities of BEF research. We suggest that distinguishing between functional response traits and functional effect traits both in combinatorial manipulations of biodiversity and in descriptive studies of BEF could markedly improve the power of such studies. We construct a possible framework for predictive, broad-scale BEF research that requires integrating functional, community, biogeographical, and ecosystem ecology with taxonomy. [source] Effect of a combination of fluoride dentifrice and varnish on enamel surface rehardening and fluoride uptake in vitroEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2003Lucianne Cople Maia The purpose of this study was to evaluate the effect of combining fluoride dentifrice (FD) and varnish (FV) on in vitro enamel surface rehardening and on fluoride uptake under a pH-cycling regimen. Seventy-eight bovine enamel blocks with early lesions were used and 52 were divided into four treatment groups: (a) placebo non-fluoridated dentifrice (PD); (b); FD (1100 p.p.m. F as NaF); (c); FV (Duraphat) + PD; and (d) FV + FD. The FV was applied to enamel blocks of groups FV + PD and FV + FD before the pH-cycling regimen, and all of them were submitted to dentifrice during cycling. Surface enamel microhardness was determined on the dental blocks before and after demineralization, and after the pH-cycling regimen. The percentage of surface microhardness recovery (%SMHR) was calculated. Fluoride in the blocks was also determined, after removing three layers of enamel. The highest values of percentage SMHR were observed for the FD group. The greatest fluoride uptake was found in the FD and FV + FD groups, but the difference between them was not statistically significant. It was found that the frequent use of fluoride dentifrice resulted in greater benefit in enamel surface rehardening, with a similar effect on fluoride uptake, when compared with its combination with a single fluoride varnish application. [source] From Central to Axial to Central Chirality: Enantioselective Construction of the trans -4,5,9,10-Tetrahydroxy-9,10-dihydrophenanthrene SystemEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 34 2007Georgi Stavrakov Abstract Enantioselective synthesis of the core trans -4,5,9,10-tetrahydroxy-9,10-dihydrophenanthrene parent system of the antibiotics benanimicin, pradimicin and FD 594 has been accomplished. The synthesis employs a chiral tether approach and makes use of efficient central to axial to central chirality transfer. Key to success was an "imine-directed" atropdiastereoselective Ullmann coupling under mild reaction conditions. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] The Impact of Regulation FD on Institutional Investor InformativenessFINANCIAL MANAGEMENT, Issue 3 2010Douglas O. Cook Although there is conflicting evidence and resulting skepticism regarding the value provided by professional investment management, Gibson, Safieddine, and Sonti (2004) document institutional investor informativeness relative to seasoned equity offering (SEO) purchases. We find that Regulation Fair Disclosure's significantly reduces institutional investors' ability to identify mispriced SEO firms. Informativeness is diminished not by investors following analysts who have experienced a reduction in forecasting accuracy, but limiting investors' direct access to private information. This information loss is replaced by reliance on a greater number of public information variables resulting in less consideration for prudence proxies and a liquidity motive and more for higher price momentum. [source] Information, Selective Disclosure, and Analyst BehaviorFINANCIAL MANAGEMENT, Issue 1 2009Anchada Charoenrook This paper examines whether the prohibition of selective disclosures to equity research analysts mandated by Regulation FD alters the amount of information and the manner in which it is revealed to the market. We demonstrate that equity research analysts are more responsive to information contained in company-initiated disclosures after Reg FD, suggesting that regulation has affected the importance of various channels of communication. We also present evidence consistent with the notion that managers use earnings guidance as a substitute for selective disclosure following the passage of Reg FD. [source] An Examination of the Differential Impact of Regulation FD on Analysts' Forecast AccuracyFINANCIAL REVIEW, Issue 1 2006Scott Findlay G14; G18; G24; G38 Abstract Regulation fair disclosure (FD) requires companies to publicly disseminate information, effectively preventing the selective pre-earnings announcement guidance to analysts common in the past. We investigate the effects of Regulation FD's reducing information disparity across analysts on their forecast accuracy. Proxies for private information, including brokerage size and analyst company-specific experience, lose their explanatory power for analysts' relative accuracy after Regulation FD. Analyst forecast accuracy declines overall, but analysts that are relatively less accurate (more accurate) before Regulation FD improve (deteriorate) after implementation. Our findings are consistent with selective guidance partially explaining variation in the forecasting accuracy of analysts before Regulation FD. [source] Characterization of the aroma-active compounds in five sweet cherry cultivars grown in Yantai (China)FLAVOUR AND FRAGRANCE JOURNAL, Issue 4 2010Shu Yang Sun Abstract This study was conducted to determine the aroma-active compounds of five sweet cherry cultivars grown in Yantai region, China, viz. ,Lapins', ,Rainier', ,Stella', ,Hongdeng' and ,Zhifuhong'. The samples were extracted by headspace solid phase microextraction (HS,SPME) and analysed by gas chromatography,mass spectrometry (GC,MS) on DB-wax and DB-5 columns. A total of 52 volatiles were identified. Among these, hexanal, (E)-2-hexenal, 1-hexanol, (E)-2-hexen-1-ol, benzaldehyde and benzyl alcohol were the main volatile compounds in the five cherries. Furthermore, the aroma compounds of five cherry samples were evaluated using a combination of HS,SPME and GC,olfactometry (GC,O) dilution analysis, and a total of 40 aroma-active compounds were identified. The results suggested that hexanal, (E)-2-hexenal, (Z)-3-hexenal, nonanal, benzaldehyde and geranylacetone (FD , 16), responsible for the green, orange, almond and floral characters of the cherries, were the potentially important common odorants in these cherry cultivars. Benzyl alcohol and linalool were significant aroma compounds in most cherries, with the exception of ,Stella' and ,Rainier'. In addition, (E,Z)-2,6-nonadienal (cucumber-like odour) could be important to ,Hongdeng' and ,Zhifuhong', and (E,E)-2,4-nonadienal (fatty odour) probably made great contributions to the aromas in ,Lapins' and ,Stella'. From the present result, it was concluded that the aroma profiles were similar in the five cherry cultivars, but significant variation was found in the contributions of these compounds to each cherry. Copyright © 2010 John Wiley & Sons, Ltd. [source] Impact of estragole and other odorants on the flavour of anise and tarragonFLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2007Annette Zeller Abstract Since estragole has been described as potent carcinogen and did not show any flavour impact on the odour of fennel, the flavour of anise and tarragon was examined by combinations of instrumental and sensory analyses. In anise fruits, trans- anethole, 2-isopropyl-3-methoxypyrazine, and anisaldehyde showed high flavour dilution (FD) factors, followed by those of eugenol, cis- anethole, estragole and linalool. Quantitation of the odorants showing higher FD factors in anise tea, and calculation of odour activity values (OAVs) by dividing the concentrations of the respective compound by its recognition threshold in water revealed the highest OAV for trans- anethole, followed by those of anisaldehyde and estragole. Still, an aroma impact of estragole next to trans- anethole could be neglected, due to former sensory studies of aqueous models of fennel tea. For tarragon, AEDA revealed the highest FD factors for eugenol, 7-methoxycoumarin, , -ionone, 2-isopropyl-3-methoxypyrazine, estragole and linalool. Of these, estragole and 7-methoxycoumarine were most abundant in tarragon leaves, showing contents of 2900 and 220 mg/kg, respectively. To calculate OAVs, the contents of potent odorants were divided by their odour threshold in starch or cellulose, as these were the main constituents of the leaves. In this way, , -ionone and eugenol showed the highest OAVs of 5862 and 2653, repectively, followed by estragole (OAV = 460), cis- 1,5-octadiene-3-one (OAV = 140), vanilline (OAV = 139) and 2-isopropyl-3-methoxypyrazine (OAV = 130). Therefore, it was concluded that , -ionone and eugenol made the greatest contribution to the overall flavour of tarragon, whereas estragole and the other odorants were of minor importance. Copyright © 2006 John Wiley & Sons, Ltd. [source] Evaluation of odour-active compounds in roasted shrimp (Sergia lucens Hansen) by aroma extract dilution analysisFLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2005Susumu Ishizaki Abstract In an investigation of roasted shrimp odour adsorbed by Tenax TA during the roasting of sun-dried sakuraebi (Sergia lucens Hansen), 31 odour-active compounds were detected by application of an aroma extract dilution analysis and subsequently identified by GC,MS analysis. Among these odorants, the following six contributed to roasted shrimp aroma, with high flavour dilution (FD) factors: methanethiol (sulphury); 1-pyrroline (shrimp meat-like); N -(2,-methylbutyl)pyrrolidine (roasted seafood-like); N -(3,-methylbutyl)pyrrolidine (roasted seafood-like); methyl isopropyl disulphide (roasted shrimp meat-like); 3-methylpyridine (fishy, green). Copyright © 2005 John Wiley & Sons, Ltd. [source] Functional biodiversity of macroinvertebrate assemblages along major ecological gradients of boreal headwater streamsFRESHWATER BIOLOGY, Issue 9 2005JANI HEINOArticle first published online: 3 AUG 200 Summary 1. Biodiversity,environment relationships are increasingly well-understood in the context of species richness and species composition, whereas other aspects of biodiversity, including variability in functional diversity (FD), have received rather little rigorous attention. For streams, most studies to date have examined either taxonomic assemblage patterns or have experimentally addressed the importance of species richness for ecosystem functioning. 2. I examined the relationships of the functional biodiversity of stream macroinvertebrates to major environmental and spatial gradients across 111 boreal headwater streams in Finland. Functional biodiversity encompassed functional richness (FR , the number of functional groups derived from a combination of functional feeding groups and habit trait groups), FD , the number of functional groups and division of individuals among these groups, and functional evenness (FE , the division of individuals among functional groups). Furthermore, functional structure (FS) comprised the composition and abundance of functional groups at each site. 3. FR increased with increasing pH, with additional variation related to moss cover, total nitrogen, water colour and substratum particle size. FD similarly increased with increasing pH and decreased with increasing canopy cover. FE decreased with increasing canopy cover and water colour. Significant variation in FS was attributable to pH, stream width, moss cover, substratum particle size, nitrogen, water colour with the dominant pattern in FS being related to the increase of shredder-sprawlers and the decrease of scraper-swimmers in acidic conditions. 4. In regression analysis and redundancy analysis, variation in functional biodiversity was not only related to local environmental factors, but a considerable proportion of variability was also attributable to spatial patterning of environmental variables and pure spatial gradients. For FR, 23.4% was related to pure environmental effects, 15.0% to shared environmental and spatial effects and 8.0% to spatial trends. For FD, 13.8% was attributable to environmental effects, 15.2% to shared environmental and spatial effects and 5% to spatial trends. For FE, 9.0% was related to environmental variables, 12.7% to shared effects of environmental and spatial variables and 4.5% to spatial variables. For FS, 13.5% was related to environmental effects, 16.9% to shared environmental and spatial effects and 15.4% to spatial trends. 5. Given that functional biodiversity should portray variability in ecosystem functioning, one might expect to find functionally rather differing ecosystems at the opposite ends of major environmental gradients (e.g. acidity, stream size). However, the degree to which variation in the functional biodiversity of stream macroinvertebrates truly portrays variability in ecosystem functioning is difficult to judge because species traits, such as feeding roles and habit traits, are themselves strongly affected by the habitat template. 6. If functional characteristics show strong responses to natural environmental gradients, they also are likely to do so to anthropogenic environmental changes, including changes in habitat structure, organic inputs and acidifying elements. However, given the considerable degree of spatial structure in functional biodiversity, one should not expect that only the local environment and anthropogenic changes therein are responsible for this variability. Rather, the spatial context, as well as natural variability along environmental gradients, should also be explicitly considered in applied research. [source] The concepts of ,plant functional types' and ,functional diversity' in lake phytoplankton , a new understanding of phytoplankton ecology?FRESHWATER BIOLOGY, Issue 9 2003Guntram Weithoff Summary 1. This is a discussion of the applicability to the phytoplankton of the concepts of ,plant functional types' (PFTs) and ,functional diversity' (FD), which originated in terrestrial plant ecology. 2. Functional traits driving the performance of phytoplankton species reflect important processes such as growth, sedimentation, grazing losses and nutrient acquisition. 3. This paper presents an objective, mathematical way of assigning PFTs and measuring FD. Ecologists can use this new approach to investigate general hypotheses [e.g. the intermediate disturbance hypothesis (IDH), the insurance hypothesis and synchronicity phenomena] as, for example, in its original formulation the IDH makes its predictions based on FD rather than species diversity. [source] On accuracy of the finite-difference and finite-element schemes with respect to P -wave to S -wave speed ratioGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2010Peter Moczo SUMMARY Numerical modelling of seismic motion in sedimentary basins often has to account for P -wave to S -wave speed ratios as large as five and even larger, mainly in sediments below groundwater level. Therefore, we analyse seven schemes for their behaviour with a varying P -wave to S -wave speed ratio. Four finite-difference (FD) schemes include (1) displacement conventional-grid, (2) displacement-stress partly-staggered-grid, (3) displacement-stress staggered-grid and (4) velocity,stress staggered-grid schemes. Three displacement finite-element schemes differ in integration: (1) Lobatto four-point, (2) Gauss four-point and (3) Gauss one-point. To compare schemes at the most fundamental level, and identify basic aspects responsible for their behaviours with the varying speed ratio, we analyse 2-D second-order schemes assuming an elastic homogeneous isotropic medium and a uniform grid. We compare structures of the schemes and applied FD approximations. We define (full) local errors in amplitude and polarization in one time step, and normalize them for a unit time. We present results of extensive numerical calculations for wide ranges of values of the speed ratio and a spatial sampling ratio, and the entire range of directions of propagation with respect to the spatial grid. The application of some schemes to real sedimentary basins in general requires considerably finer spatial sampling than usually applied. Consistency in approximating first spatial derivatives appears to be the key factor for the behaviour of a scheme with respect to the P -wave to S -wave speed ratio. [source] Parsimonious finite-volume frequency-domain method for 2-D P,SV -wave modellingGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 2 2008R. Brossier SUMMARY A new numerical technique for solving 2-D elastodynamic equations based on a finite-volume frequency-domain approach is proposed. This method has been developed as a tool to perform 2-D elastic frequency-domain full-waveform inversion. In this context, the system of linear equations that results from the discretization of the elastodynamic equations is solved with a direct solver, allowing efficient multiple-source simulations at the partial expense of the memory requirement. The discretization of the finite-volume approach is through triangles. Only fluxes with the required quantities are shared between the cells, relaxing the meshing conditions, as compared to finite-element methods. The free surface is described along the edges of the triangles, which can have different slopes. By applying a parsimonious strategy, the stress components are eliminated from the discrete equations and only the velocities are left as unknowns in the triangles. Together with the local support of the P0 finite-volume stencil, the parsimonious approach allows the minimizing of core memory requirements for the simulation. Efficient perfectly matched layer absorbing conditions have been designed for damping the waves around the grid. The numerical dispersion of this FV formulation is similar to that of O(,x2) staggered-grid finite-difference (FD) formulations when considering structured triangular meshes. The validation has been performed with analytical solutions of several canonical problems and with numerical solutions computed with a well-established FD time-domain method in heterogeneous media. In the presence of a free surface, the finite-volume method requires 10 triangles per wavelength for a flat topography, and fifteen triangles per wavelength for more complex shapes, well below the criteria required by the staircase approximation of O(,x2) FD methods. Comparisons between the frequency-domain finite-volume and the O(,x2) rotated FD methods also show that the former is faster and less memory demanding for a given accuracy level, an attractive feature for frequency-domain seismic inversion. We have thus developed an efficient method for 2-D P,SV -wave modelling on structured triangular meshes as a tool for frequency-domain full-waveform inversion. Further work is required to improve the accuracy of the method on unstructured meshes. [source] Can Contaminant Transport Models Predict Breakthrough?GROUND WATER MONITORING & REMEDIATION, Issue 4 2000Wei-Shyuan "Stone" Peng A solute breakthrough curve measured during a two-well tracer test was successfully predicted in 1986 using specialized contaminant transport models. Water was injected into a confined, unconsolidated sand aquifer and pumped out 125 feet (38.3 m) away at the same steady rate. The injected water was spiked with bromide for over three days; the outflow concentration was monitored for a month. Based on previous tests, the horizontal hydraulic conductivity of the thick aquifer varied by a factor of seven among 12 layers. Assuming stratified flow with small dispersivities, two research groups accurately predicted breakthrough with three-dimensional (12-layer) models using curvilinear elements following the arc-shaped flowlines in this test. Can contaminant transport models commonly used in industry, that use rectangular blocks, also reproduce this breakthrough curve? The two-well test was simulated with four MODFLOW-based models, MT3D (FD and HMOC options), MODFLOWT, MOC3D, and MODFLOW-SURFACT. Using the same 12 layers and small dispersivity used in the successful 1986 simulations, these models fit almost as accurately as the models using curvilinear blocks. Subtle variations in the curves illustrate differences among the codes. Sensitivities of the results to number and size of grid blocks, number of layers, boundary conditions, and values of dispersivity and porosity are briefly presented. The fit between calculated and measured breakthrough curves degenerated as the number of layers and/or grid blocks decreased, reflecting a loss of model predictive power as the level of characterization lessened. Therefore, the breakthrough curve for most field sites can be predicted only qualitatively due to limited characterization of the hydrogeology and contaminant source strength. [source] A sensitive mutation-specific screening technique for GNAS1 mutations in cases of fibrous dysplasia: the first report of a codon 227 mutation in boneHISTOPATHOLOGY, Issue 6 2007B D Idowu Aims:, To report on the mutation-specific restriction enzyme digest (MSRED) method using paraffin-embedded tissue as a means of detecting GNAS1 mutations in fibrous dysplasia (FD), and to determine if any of the reported GNAS1 mutations in endocrine neoplasms, not previously documented in FD, can be found in FD. Methods and results:, Sixty-seven cases of extragnathic FD were analysed as two groups, 1997,2002 and 2003,06, chosen because tissue fixation and decalcification methods were more accurately recorded in the latter. MSRED revealed that between 2003 and 2006, 93% of 28 ,in house' extragnathic cases harboured a GNAS1 mutation, compared with 75% of 32 cases before 2003. Fixation times of no more than 48 h and decalcification in ethylenediamine tetraacetic acid gave the best results. Of the 56 mutations detected (five gnathic, 51 extragnathic), 32 (57%) were R201H, 21 (38%) were R201C and three (5%) were Q227L. Two Q227L extragnathic cases had unusual clinical/radiological findings. No mutations were detected in osteofibrous dysplasia. Conclusion:, Detection of GNAS1 mutations by MSRED is a valuable adjunct to the histopathological diagnosis of FD. This is the first report of a Q227L mutation in FD, although it has been previously documented in pituitary adenoma. [source] FOIST: Fluid,object interaction subcomputation techniqueINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 9 2009V. Udoewa Abstract Our target is to develop computational techniques for studying aerodynamic interactions between multiple objects. The computational challenge is to predict the dynamic behavior and path of the object, so that separation (the process of objects relatively falling or moving away from each other) is safe and effective. This is a very complex problem because it has an unsteady, 3D nature and requires the solution of complex equations that govern the fluid dynamics (FD) of the object and the aircraft together, with their relative positions changing in time. Large-scale 3D FD simulations require a high computational cost. Not only must one solve the time-dependent Navier,Stokes equations governing the fluid flow, but also one must handle the equations of motion of the object as well as the treatment of the moving domain usually treated as a type of pseudo-solid. These costs include mesh update methods, distortion-limiting techniques, and remeshing and projection tactics. To save computational costs, point force calculations have been performed in the past. This paper presents a hybrid between full mesh-moving simulations and the point force calculation. This mesh-moving alternative is called FOIST: fluid,object subcomputation interaction technique. Copyright © 2009 John Wiley & Sons, Ltd. [source] The maximum principle violations of the mixed-hybrid finite-element method applied to diffusion equationsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 12 2002H. Hoteit Abstract The abundant literature of finite-element methods applied to linear parabolic problems, generally, produces numerical procedures with satisfactory properties. However, some initial,boundary value problems may cause large gradients at some points and consequently jumps in the solution that usually needs a certain period of time to become more and more smooth. This intuitive fact of the diffusion process necessitates, when applying numerical methods, varying the mesh size (in time and space) according to the smoothness of the solution. In this work, the numerical behaviour of the time-dependent solutions for such problems during small time duration obtained by using a non-conforming mixed-hybrid finite-element method (MHFEM) is investigated. Numerical comparisons with the standard Galerkin finite element (FE) as well as the finite-difference (FD) methods are checked. Owing to the fact that the mixed methods violate the discrete maximum principle, some numerical experiments showed that the MHFEM leads sometimes to non-physical peaks in the solution. A diffusivity criterion relating the mesh steps for an artificial initial,boundary value problem will be presented. One of the propositions given to avoid any non-physical oscillations is to use the mass-lumping techniques. Copyright © 2002 John Wiley & Sons, Ltd. [source] A pseudospectral Fourier method for a 1D incompressible two-fluid modelINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 6 2008H. Holmås Abstract This paper presents an accurate and efficient pseudospectral (PS) Fourier method for a standard 1D incompressible two-fluid model. To the knowledge of the authors, it is the first PS method developed for the purpose of modelling waves in multiphase pipe flow. Contrary to conventional numerical methods, the PS method combines high accuracy and low computational costs with flexibility in terms of handling higher order derivatives and different types of partial differential equations. In an effort to improve the description of the stratified wavy flow regime, it can thus serve as a valuable tool for testing out new two-fluid model formulations. The main part of the algorithm is based on mathematical reformulations of the governing equations combined with extensive use of fast Fourier transforms. All the linear operations, including differentiations, are performed in Fourier space, whereas the nonlinear computations are performed in physical space. Furthermore, by exploiting the concept of an integrating factor, all linear parts of the problem are integrated analytically. The remaining nonlinear parts are advanced in time using a Runge,Kutta solver with an adaptive time step control. As demonstrated in the results section, these steps in sum yield a very accurate, fast and stable numerical method. A grid refinement analysis is used to compare the spatial convergence with the convergence rates of finite difference (FD) methods of up to order six. It is clear that the exponential convergence of the PS method is by far superior to the algebraic convergence of the FD schemes. Combined with the fact that the scheme is unconditionally linearly stable, the resulting increase in accuracy opens for several orders of magnitude savings in computational time. Finally, simulations of small amplitude, long wavelength sinusoidal waves are presented to illustrate the remarkable ability of the PS method to reproduce the linear stability properties of the two-fluid model. Copyright © 2008 John Wiley & Sons, Ltd. [source] Projection and partitioned solution for two-phase flow problemsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 12 2005Andrea Comerlati Abstract Multiphase flow through porous media is a highly nonlinear process that can be solved numerically with the aid of finite elements (FE) in space and finite differences (FD) in time. For an accurate solution much refined FE grids are generally required with the major computational effort consisting of the resolution to the nonlinearity frequently obtained with the classical Picard linearization approach. The efficiency of the repeated solution to the linear systems within each individual time step represents the key to improve the performance of a multiphase flow simulator. The present paper discusses the performance of the projection solvers (GMRES with restart, TFQMR, and BiCGSTAB) for two global schemes based on a different nodal ordering of the unknowns (ORD1 and ORD2) and a scheme (SPLIT) based on the straightforward inversion of the lumped mass matrix which allows for the preliminary elimination and substitution of the unknown saturations. It is shown that SPLIT is between two and three time faster than ORD1 and ORD2, irrespective of the solver used. Copyright © 2005 John Wiley & Sons, Ltd. [source] Use of real-time FT-IR monitoring of a pharmaceutical compound under stress atmospheric conditions to characterize its solid-state degradation kineticsINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 1 2010Peter J. Skrdla The use of online FT-IR is described for investigating the degradation kinetics of the solid amorphous pharmaceutical compound, fosaprepitant dimeglumine (FD), under stress storage conditions (i.e., high temperature, T, and humidity, % RH). It is found that under conditions of elevated T and % RH, the kinetics are denucleation rate limited for the deliquescence of the amorphous FD solid, based on the high quality fits obtained to the authors' dispersive kinetic model for that mechanism. At elevated T and low % RH, it is found that a classical, first-order hydrolysis mechanism for the degradation of FD (which forms crystalline aprepitant, AP) significantly contributes to the overall conversion rate. That mechanism is similar to the one observed previously for the solution-phase hydrolysis of FD. Appropriate kinetic models are proposed for the FD-to-AP conversion under all of the experimental conditions investigated in this work. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 42: 25,36, 2010 [source] Studies on different combined microwave drying of carrot piecesINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2010Wei-Qiang Yan Summary Three different combined microwave (MW) drying methods were compared, namely microwave-assisted vacuum drying (MWVD), microwave-assisted freeze drying (MWFD), microwave-enhanced spouted bed drying (MWSD), in terms of drying rate, drying uniformity, product colour, rehydration ratio, retention of , - carotene and vitamin C, and energy consumption. The drying rate of MWVD and MWSD were much faster than that of MWFD. The largest drying rate was obtained in MWSD with 3.5 W g,1. In general, the colour of MWSD products was very uniform. Rehydration ratio of MWFD carrot pieces was almost the same as the freeze-dried (FD) products and better than MWVD and MWSD products. In addition, the highest retention of carotene and vitamin C was observed in MWFD carrot pieces. No significant differences were observed in carotene and vitamin C between MWVD and MWSD products. However, the energy consumption in MWFD was the highest. [source] Modelling of lossy curved surfaces in the 3-D frequency-domain finite-difference methodsINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 5 2006Riku M. Mäkinen Abstract A conformal first-order or Leontovic surface-impedance boundary condition (SIBC) for the modelling of fully three-dimensional (3-D) lossy curved surfaces in a Cartesian grid is presented for the frequency-domain finite-difference (FD) methods. The impedance boundary condition is applied to auxiliary tangential electric and magnetic field components defined at the curved surface. The auxiliary components are subsequently eliminated from the formulation resulting in a modification of the local permeability value at boundary cells, allowing the curved 3-D surface to be described in terms of Cartesian grid components. The proposed formulation can be applied to model skin-effect loss in time-harmonic driven problems. In addition, the impedance matrix can be used as a post-processor for the eigenmode solver to calculate the wall loss. The validity of the proposed model is evaluated by investigating the quality factors of cylindrical and spherical cavity resonators. The results are compared with analytic solutions and numerical reference data calculated with the commercial software package CST Microwave StudioÔ (MWS). The convergence rate of the results is shown to be of second-order for smooth curved metal surfaces. The overall accuracy of the approach is comparable to that of CST MWSÔ. Copyright © 2006 John Wiley & Sons, Ltd. [source] Evaluation of DRAINMOD-S for simulating water table management under semi-arid conditions,IRRIGATION AND DRAINAGE, Issue 3 2002M. A. S. Wahba modèl e dela direction dela table d'eau souterraine; le drainage conventionnel; le drainage contrôlé Abstract The water table management simulation model, DRAINMOD-S, was evaluated under semi-arid conditions using field data from the Maruit experimental field in the western delta of Egypt for three cropping seasons; maize 1999, wheat 1999/2000 and maize 2000. Two water table management systems (conventional drainage (FD) and controlled drainage (CD)) were applied in the study area. The recorded data included daily ground water table depths, drain outflows during flow events, soil salinity to depth of 1.20 m from the soil surface (0.30 m interval), and relative crop yield. DRAINMOD-S was run to simulate the applied water table management systems for the same study periods. The reliability of the model was evaluated by comparing measured and predicted values of the daily ground water table depth, cumulative outflow based on total monthly outflow, soil salinity during each season, and relative crop yield. Good agreement was found between the measured and predicted values. DRAINMOD-S predicted values within an absolute deviation ranged from 11.0 to 16.0 cm for ground water table depth, from 18 to 75 mm for drain outflows, from 0.22 to 1.08 dS m,1 for soil salinity, and from 4.62 to 4.86% for relative crop yield. The model showed the potential for long-term simulation and planning of ground water table management systems under semi-arid conditions of the western delta of Egypt. Copyright © 2002 John Wiley & Sons, Ltd. RÉSUMÉ Le modèle DRAINMOD-S pour simuler la direction de la table d'eau sous des conditions demi-arides á été évalué en utilisant le data des champs experimentaux du Mariut delta denileouest d'Égypte pendant trois saisons agricoles: le maïs 1999, le blé 1999/2000 et le maïs 2000. Deux systèmes de direction de la table d'eau (drainage conventionnel (FD) et drainage contrôlé (CD)) ontété appliqués àla superficie de l'étude. Le data qui s'est remis en ordre s'inclut les mesures des profondeurs de la table d'eau souterraine, les écoulements des drains pendant les évènements de l'écoulement, la salinité du sol au profondeur de 1.20 m souterrain aux intervalles de 30 cm, etles produits agricoles relatifs. DRAINMOD-S S'est mis en courant pour simuler l'application des systèmes de la direction pour la même période d'étude. La véracité du modèle aété évaluée en comparant les valeurs mésurées avec lcelles des produits agricoles sur le profondeur de la table d'eau quotidien, l'écoulement cumulatif basé sur l'écoulement total du mois, la salinité du sol pendant chaque saison, et les produits agricoles relatifs. On a trouvé un bon accord entre les valeurs mésurées et celles qu'on avait prédites avec une déviation absolue qui rangeait de 11.0 à 16.0 cm pour la profondeur de la table d'eau, de 18 à 75 mm pour l'écoulement du drains, et de 0.22 à 1.08 dS m,1, pour la salinité du sol et de 4.62 à 4.86% pour les produits agricoles relatifs. Le modèle a indiqué une éfficacité pour une simulation allongée et pour projeter les systèmes de la direction dela table d'eau souterraine auprès les conditions demi-arides du delta ouest en Egypte. Copyright © 2002 John Wiley & Sons, Ltd. [source] Controlled drainage effects on water quality under semi-arid conditions in the western delta of EgyptIRRIGATION AND DRAINAGE, Issue 4 2001M.A.S. Wahba le drainage contrôlé; le drainage conventionnel; la gestion de la liste de l'eau; la qualité de l'eau de drainage Abstract Field experiments were conducted for two years in the Western Delta of Egypt to investigate the effects of controlled drainage on the quality of subsurface drainage outflows. Two water table management methods were applied in the 2.54 ha experimental field: free conventional subsurface drainage and controlled drainage. Controlled drainage was applied at 60 cm depth during both seasons. Drain discharge volumes and nitrate-N and orthophosphate-phosphorus concentrations were monitored during the growing seasons. The controlled drainage (CD) treatment significantly reduced the total drainage outflow by 68% during the summer season and by 28% during the winter of 1999,2000 at 99% confidence level, compared to free conventional drainage (FD) treatment. The CD also reduced the total nitrate-N in drainage water by 73%, and 32% during the summer and the winter seasons respectively, compared to the FD treatment. The CD treatment reduced the total orthophosphate-phosphorus losses by 77% during summer of 1999 and by 30% during winter of 1999,2000 compared to the FD treatment; however, in general the total mass loss was low in both treatments. The results of the experiment showed the potential environmental and economic benefits with the application of controlled drainage in semi-arid regions. Copyright © 2001 John Wiley & Sons, Ltd. Les expériences sur les domaines étaient dirigées pour deux ans dans le delta de l'ouest de l'Egypte, pour étudier les effets du drainage contrôlé sur la qualité de l'écoulement du drainage sous-surface. Deux méthodes du direction de table de l'eau ont été appliquées sur environ 2.54 ha domaines d'expériences, du drainage conventionnel sous-surface libre, et du drainage contrôlé. Le drainage contrôlé était appliqué a 60 cm de profondeur durant les deux saisons, les concentrations des volumes du drain déchargé et du nitrate-N, et les orthophosphate-phosphours étaient surveillées durant les saisons nouvelles. Le drainage contrôlé (DC) traitement a diminué considérablement le total de charge du drainage par taux de 68% durant l'été et par 28% pendant l'hiver de 1999,2000 par 99%, le niveau de confiance en comparaison au traitement du drainage conventionnel libre (DL). Le drainage contrôlé a diminué le taux total du nitrate-N dans l'eau de drainage par taux de 73% pendant l'été et 32% pendant l'hiver comparé avec le traitement du drainage libre. Le drainage contrôlé du taux total d'orthophosphate-phosphours perdu a diminué par 77% pendant l'été 1999, et 30% pendant l'hiver de 1999,2000 comparé avec le traitement du drainage libre, mais en général la masse totale perdue a diminué. Les résultats ont présenté le potentiel environnemental et les bénéfits économiques de l'application du drainage contrôlé dans les régions semi-arides. Copyright © 2001 John Wiley & Sons, Ltd. [source] The effect of introducing pipelines into irrigation water distribution systems on the farm economy: a case study in the Southern Governorates Rural Development Project, Republic of Yemen,IRRIGATION AND DRAINAGE, Issue 1 2001Rozgar Baban le Yémen; eau souterraine; irrigation; tuyaux Abstract The Southern Governorates Rural Development Project (SGRDP) is a comprehensive participatory rural development project covering three of the five southern Governorates of the Republic of Yemen, namely Hadramaut, Abyan and Lahij. Its objective is to alleviate poverty in rural areas of these three Governorates. A major component of the project is to develop virgin lands for agriculture and allocate each 5 feddan (FD) plot to those farmers who do not own land (1 FD=4200 m2). As the annual rainfall in the project area is less than 100 mm and since landlords and other farmers already own lands suitable for agriculture in the major wadis, the only source of irrigation water in the newly developed land is the groundwater (GW). The SGRDP is aware of the scarcity of water resources in the country, particularly in the project area; it therefore makes every possible effort to optimize the use of GW for irrigation by practical means. One way of reducing GW used for irrigation is by replacing major canals in the farms by buried pipelines. This method has been tried in small-scale individual farms outside the project area and it proved that farmers could adapt to the system without difficulty. Sprinkler and drip irrigation systems have been tried in many previous agricultural development projects in the country but with no apparent success, as far as the farmers' adoption of the method is concerned. Thus, the project, as the first stage to reduce the use of GW for irrigation in the newly developed areas, planned to eliminate, initially, the conveyance losses by replacing the open canals by buried PVC pipes. In this paper, it is attempted to show that the use of buried pipes in small scale irrigation schemes is financially feasible, even if the indirect and non-tangible environmental benefits are not considered. This paper deals only with special GW schemes recommended for the project area; however, the outcome could be generalized and applied elsewhere in the country. Copyright © 2001 John Wiley & Sons Ltd. Le Projet de Développement Rural des Gouvernorats du Sud (SGRDP) est un ensemble de projet de développement rural participatif de trois des cinq Gouvernorats de la République de Yémen à savoir Hadramaut, Abyan et Lahij. Son objectif est d'atténuer la pauvreté dans les régions rurales de ces Gouvernorats. L'une des principales activités de ce projet concerne le développement des terres incultes pour l'agriculture. Ce développement passe par l'allocation de parcelles de 5 FD à chaque agriculteur sans terre. Comme la pluviosité annuelle dans cette région est inférieure à 100 mm et que les propriétaires et les autres fermiers disposent déjà des terres aptes à l'agriculture dans les WADIS importants, l'eau souterraine est la seule source d'eau pour l'irrigation des terres nouvellement développées. Compte tenu de la rareté des ressources en eau, particulièrement dans la région du projet, le SGRDP s'efforce d'optimiser l'utilisation de l'eau souterraine (ES) pour l'irrigation en adoptant des moyens pratiques. L'un des moyens de réduire l'ES utilisée en irrigation consiste à remplacer les principaux canaux des fleuves par des tuyaux enterrés. Cette méthode a été utilisée à titre d'essai dans des exploitations individuelles de petite taille en dehors de la région du projet, et il s'est avéré que les agriculteurs peuvent s'adapter à ce système sans difficultés. Les systèmes d'irrigation par aspersion et goutte à goutte ont été essayés dans de nombreux anciens projets de développement agricoles du pays, mais sans succès apparent quant à l'adoption de cette méthode par les fermiers. Ainsi, le projet, en tant que première stade de réduction de l'ES pour l'irrigation dans les régions nouvellement développées, a proposé d'éliminer au début les pertes par transport en remplaçant les canaux ouverts par des tuyaux PVC enterrés. Ce rapport essaie de montrer que l'utilisation des tuyaux enterrés dans les projets d'irrigation de petite taille, est faisable du point de vue économique même en faisant abstraction des avantages indirects et non tangibles provenant de l'environnement. Le rapport traite seulement des projets spéciaux de l'ES recommandés pour la région du projet. Cependant, les résultats peuvent être généralisés et appliqués aux autres régions du pays. Copyright © 2001 John Wiley & Sons Ltd. [source] Effects of Plant Population Density and Intercropping with Soybean on the Fractal Dimension of Corn Plant Skeletal ImagesJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2000K. Foroutan-pour Three-year field experiments were conducted to determine whether the temporal pattern of fractal dimension (FD) for corn (Zea mays L.) plant structure is altered by plant population density (PPD) or intercropping with soybean [Glycine max. (L.) Merr.], and how changes in the FD are related to changes in other canopy characteristics. Plants in monocropped corn and intercropped corn,soybean plots were randomly sampled and labelled for later identification. Corn plant structure was photographed from the side that allowed the maximum appearance of details (perpendicular to the plane of developed leaves) and from two fixed sides (side 1: parallel to the row and side 2: perpendicular to the row). Images were scanned and skeletonized, as skeletal images provide acceptable information to estimate the FD of plant structure two-dimensionally by the box-counting method. Differences in the FD estimated from images taken perpendicular to the plane of developed leaves were not significant among competition treatments. An adjustment of corn plants to treatments, by changing the orientation of the plane of developed leaves with respect to the row, was observed. Based on overall FD means, competition treatments were ranked as: high > normal , intercrop , low for side 1 and intercrop > low , normal > high for side 2. Leaf area index (LAI) and plant height had a positive correlation with FD. In contrast, light penetration had a negative correlation with FD. In conclusion, FD provides a meaningful and effective tool for quantifying corn plant structure, measuring the structural response to cultural practices, and modelling corn plant canopies. Zusammenfassung Folgende Ziele der Untersuchungen wurden berücksichtigt: 1) Eine geeignete Methode für die Abschätzung der Anteile (FD) 2-dimensional für Pflanzen mit einer einfachen dreidimensionalen Vegetationsstruktur wie z. B. Mais (Zea mays L.) zu bestimmen; 2) der Frage nachzugehen, ob die zeitlichen Muster von FD bei der Maispflanzenstruktur durch die Bestandesdichte verändert wird (PPD: low, normal und hoch) oder in Mischanbau mit Sojabohnen (Glyzine max. L.) Merr.); und 3) in welcher Beziehung Änderungen in der FD in der Maispflanzenstruktur zu Änderungen in anderen Bestandeseigenschaften stehen. Pflanzen im Reinanbau von Mais und im Mischanbau in Mais-Sojabohnen-Parzellen wurden randomisiert gesammelt und für die spätere Identifikation gekennzeichnet. Die Maispflanzenstruktur wurde von der Seite fotografiert, so dai eine maximale Darstellung der Details (perpendiculär zu der Ebene der entwickelten Blätter) und von zwei festgelegten Seiten (Seite 1: parallel zur Reihe und Seite 2 perpendikulär zur Reihe) verfügbar war. Die Abbildungen wurden gescannt und skelettiert; Skelettabbildungen geben eine akzeptierbare Information zur Abschätzung von FD Pflanzenstrukturen in zweidimensionaler Form über die Box-counting-Methode. Unterschiede in der FD, die sich aus Bildern mit einer perpendikulären Aufnahme zu der Ebene der entwickelten Blätter ergaben, waren nicht signifikant innerhalb der Konkurrenzbehandlungen. Eine Anpassung der Maispflanzen an die Behandlungen durch Änderungen der Orientierung zur Ebene der entwickelten Blätter im Hinblick auf die Reihe, wurde beobachtet. Auf der Grundlage von gesamt FD-Mittelwerten ergab sich, dai Konkurrenzbehandlungen in folgender Reihe auftraten: Hoch (1,192) > (1,178) , zu Mischanbau (1,177) , zu gering (1,170) für Seite 1 und bei Mischanbau (1,147) > gering (1,158) , (1,153) > hoch für Seite 2. Der Blattflächenindex (LAI) und die Pflanzenhöhe hatten eine positive Korrelation zu FD. Im Gegensatz dazu wies die Lichtpenetration eine negative Korrelation zu FD auf. Es kann festgestellt werden, dai FD eine aussagekräftige und zweckmäiige Methode ist, die Maispflanzenstruktur zu quantifizieren, Strukturreaktionen zum Anbauverfahren zu messen und Maispflanzenbestände zu beschreiben. [source] Genetic correlations among and between wool, growth and reproduction traits in Merino sheepJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 2 2007E. Safari Summary Data from seven research resource flocks across Australia were combined to provide accurate estimates of genetic correlations among production traits in Merino sheep. The flocks represented contemporary Australian Merino fine, medium and broad wool strains over the past 30 years. Over 110 000 records were available for analysis for each of the major wool traits, and 50 000 records for reproduction and growth traits with over 2700 sires and 25 000 dams. Individual models developed from the single trait analyses were extended to the various combinations of two-trait models to obtain genetic correlations among six wool traits [clean fleece weight (CFW), greasy fleece weight, fibre diameter (FD), yield, coefficient of variation of fibre diameter and standard deviation of fibre diameter], four growth traits [birth weight, weaning weight, yearling weight (YWT), and hogget weight] and four reproduction traits [fertility, litter size, lambs born per ewe joined, lambs weaned per ewe joined (LW/EJ)]. This study has provided for the first time a comprehensive matrix of genetic correlations among these 14 wool, growth and reproduction traits. The large size of the data set has also provided estimates with very low standard errors. A moderate positive genetic correlation was observed between CFW and FD (0.29 ± 0.02). YWT was positively correlated with CFW (0.23 ± 0.04), FD (0.17 ± 0.04) and LWEJ (0.58 ± 0.06), while LW/EJ was negatively correlated with CFW (,0.26 ± 0.05) and positively correlated with FD (0.06 ± 0.04) and LS (0.68 ± 0.04). These genetic correlations, together with the estimates of heritability and other parameters provide the basis for more accurate prediction of outcomes in complex sheep-breeding programmes designed to improve several traits. [source] Making Financial Goals and Reporting Policies ServeJOURNAL OF APPLIED CORPORATE FINANCE, Issue 4 2004Corporate Strategy: The Case of Progressive Insurance The main. nancial goal of Progressive Insurance, the third largest underwriter of auto insurance in the U.S., has remained the same since the late 1960s. Expressed in three words, "96 and grow," the goal tells the company's managers to pursue all growth opportunities while maintaining a "combined ratio" no higher than 96, or what amounts to a minimum 4% spread between revenues (premiums) and costs (including expected losses). Thanks in part to the clarity of mission provided by this goal, the company has produced an average 15% rate of growth in revenues and earnings, along with a remarkably stable 15% return for its shareholders, since going public in 1971. Progressive's simplicity and clarity of mission is also partly responsible for another of the company's distinctive policies: product pricing that, while disciplined, is aggressive and highly decentralized. Having invested some $500 million per year developing statistical models for pricing individual customer risks and acquisition costs, the company was among the. rst in its industry to underwrite "non-standard" risks. And aided by sophisticated pricing models, each of Progressive's 100 or so local product managers are charged with adapting those models to come up with premiums for their own regions. To go along with its strategic and organizational innovations, Progressive also has an innovative disclosure policy. Apart from SEC reports, the company's communications seldom mention earnings or earnings per share, and the company has never provided earnings guidance. With the passage of Reg. FD in late 2000, the company brie. y considered offering guidance. But in the spring of 2001, the board decided instead to provide monthly releases of its realized combined ratio. Since adoption of this new disclosure policy, Progressive has seen a 50% drop in the volatility of its stock price. [source] Host culling as an adaptive management tool for chronic wasting disease in white-tailed deer: a modelling studyJOURNAL OF APPLIED ECOLOGY, Issue 2 2009Gideon Wasserberg Summary 1Emerging wildlife diseases pose a significant threat to natural and human systems. Because of real or perceived risks of delayed actions, disease management strategies such as culling are often implemented before thorough scientific knowledge of disease dynamics is available. Adaptive management is a valuable approach in addressing the uncertainty and complexity associated with wildlife disease problems and can be facilitated by using a formal model. 2We developed a multi-state computer simulation model using age, sex, infection-stage, and seasonality as a tool for scientific learning and managing chronic wasting disease (CWD) in white-tailed deer Odocoileus virginianus. Our matrix model used disease transmission parameters based on data collected through disease management activities. We used this model to evaluate management issues on density- (DD) and frequency-dependent (FD) transmission, time since disease introduction, and deer culling on the demographics, epizootiology, and management of CWD. 3Both DD and FD models fit the Wisconsin data for a harvested white-tailed deer population, but FD was slightly better. Time since disease introduction was estimated as 36 (95% CI, 24,50) and 188 (41,>200) years for DD and FD transmission, respectively. Deer harvest using intermediate to high non-selective rates can be used to reduce uncertainty between DD and FD transmission and improve our prediction of long-term epidemic patterns and host population impacts. A higher harvest rate allows earlier detection of these differences, but substantially reduces deer abundance. 4Results showed that CWD has spread slowly within Wisconsin deer populations, and therefore, epidemics and disease management are expected to last for decades. Non-hunted deer populations can develop and sustain a high level of infection, generating a substantial risk of disease spread. In contrast, CWD prevalence remains lower in hunted deer populations, but at a higher prevalence the disease competes with recreational hunting to reduce deer abundance. 5Synthesis and applications. Uncertainty about density- or frequency-dependent transmission hinders predictions about the long-term impacts of chronic wasting disease on cervid populations and the development of appropriate management strategies. An adaptive management strategy using computer modelling coupled with experimental management and monitoring can be used to test model predictions, identify the likely mode of disease transmission, and evaluate the risks of alternative management responses. [source] | |||||||||||||||||||||||||||||||||||||||||||