Search

The ecological niche sensu Hutchinson is defined as the set of environmental conditions allowing a species to grow, maintain, and reproduce. This conception of the niche, which is assimilated to a p‐dimensional hypervolume, with p representing all environmental variables, has been widely applied in ecology. However, displaying the niche hypervolume has proved challenging when more than three environmental dimensions are considered simultaneously. We propose a simple method (implemented in the specieschrom R package) that displays the full multidimensionality of the ecological niche of a species into a two‐dimensional space by means of a graphic we call species chromatogram. This method gives a graphical summary of the niche by representing together abundance gradients with respect to all environmental variables. A chromatogram enables niche optimums and breaths to be rapidly quantified, and when several chromatograms are examined (one per species), rapid comparisons can be made. From our chromatograms, we proposed a procedure that quantifies niche optimum and breadth as well as niche overlapping (index D) and the identification of the most discriminant combination of environmental variables. We apply these analyses on eight planktonic species collected by the Continuous Plankton Recorder (CPR) survey in the North Atlantic Ocean using 10 environmental variables. We display their full multidimensional niches and quantify their niche optimums and breadths along each dimension. We also compare our index D with other indices by means of hypervolume and dynRB R packages. By catching the full complexity of the niche, species chromatograms allow many different niche properties to be rapidly assessed and compared among species from niche optimums and breadths to the identification of the most relevant environmental parameters and the degree of niche overlapping among species. Species chromatograms may be seen as species' fingerprint and may also allow a better identification of the mechanisms involved in species assembly. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) funicular structures can be easily generated and controlled by means of simple geometric constructions. These geometric constructions derive from reciprocal relationships between the form and force diagrams of a structure, which form the basis of graphic statics. Unlike in 2D space, in 3D space, similar geometric constructions cannot always be established for the design of three‐dimensional (3D) funicular structures. In some specific cases though, purely geometric procedures requiring no numerical approximations can be defined. In particular, this contribution explores the geometric transformation of 2D funicular structures as a means to graphically generate 3D funicular structures in equilibrium with coplanar loads. A fully graphical method for the construction of such pairs of 3D skew funiculars in equilibrium with coplanar loads and with control over the position of the supports is presented. It is based on geometrical linear relationships between the original and the transformed structures. Ultimately, it is shown how such pairs of 3D skew funiculars can be applied to the design of bridge and roof structures for instance. [ABSTRACT FROM AUTHOR]

Increasing effort of solar power integration to the grid could be accelerated towards sustainability goal. However, high PV penetration ratio (PVR) in turn critically reduces system frequency response performance of an existing power system due to reduction of on‐line rotating generators. Besides intrinsic system inertia, system RC plays a vital role in dynamically securing the power system operation subject to large PV disturbances. This study proposes a graphical method to determine critical values of system RC requirement with respect to the anticipated PVR and PV ramp‐down rate of disturbance; both of which should be forecastable, in practice, in each operating time interval. Impact of PVR on dynamic performance of a power system, through the effective time‐varying of system inertia and governor response characteristic has been examined. The results of the analyses on graphical display will be useful for system operators to prepare enough system RC, economically well in‐advance through Unit Commitment program, to ensure system dynamic security, complying with the N‐1 contingency constraint. In addition, the proposed graphical display can reveal whether the curtailment of aggregated PV's output generation is necessary for that time interval. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

GGE biplot technique is one of the appropriate methods for investigating the genotype–environment interaction. An experiment was conducted to examine and evaluate the stability and adaptability of grain yield of 12 sunflower genotypes using the randomized complete block design (RCBD) with three replications in five regions including Karaj, Birjand, Firooz‐Abad, Kashmar, and Arak within two agricultural years. Analysis of variance indicated that the effect of location, year, location × year, genotype, and genotype × location was significant at 1% probability level. Results of biplot analysis showed that the first and second principle components accounted 50.6% and 22.8%, respectively, and in total 73.4% of grain yield variance. In this study, genotype, location, year, year × location, genotype × location, genotype × year, and genotype × year × location explained 2.75%, 17.36%, 5.47%, 17%, 10.8%, 1.04%, and 7.48% of total variance, respectively. Investigating the polygon view led to the identification of three top genotypes and also three mega‐environment. The first mega‐environment included Karaj, Birjand, and Kashmar. The second was Arak, and the third was Firooz‐Abad. To study the kernel yield and stability of genotypes simultaneously, average coordinate view of environments was used and it was determined that genotype Zaria with the highest grain yield has high yield stability also. Ranking the cultivars based on the ideal genotype introduced the genotype Zaria as the best genotype. The highest grain yield belonged to Zaria cultivar at 3.34 t/ha followed by Favorite with 3.23 t/ha. Results obtained from ranking the environments based on the ideal environment introduced Kashmar and Birjand regions as the best environments. Examining the biplot figure for testing environments correlation confirms the positive correlation among Karaj, Birjand, and Kashmar. Correlation between Karaj with Arak, Karaj with Firooz‐Abad, and Arak with Firooz‐Abad was negative. Arak and Firooz‐Abad were highly discriminating and representative and would be used to identification of superior genotypes. [ABSTRACT FROM AUTHOR]

An intuitive method is presented for detecting pseudosymmetries in Z′ > 1 cases as a complement to well‐proven strategies already available in the literature. It is based in the simple idea that the mid‐points between equivalent atoms in symmetrically related molecules are disposed according to simple well‐known patterns, which are easily recognizable by optical inspection. A number of Z′ = 4 cases in the literature are analyzed, which allows some of the potentialities of the method to be revealed. [ABSTRACT FROM AUTHOR]

Purpose: Dynamic 18F‐FDG PET allows quantitative estimation of cerebral glucose metabolism both at the regional and local (voxel) level. Although sensitive to noise and highly computationally expensive, nonlinear least‐squares (NLS) optimization stands as the reference approach for the estimation of the kinetic model parameters. Nevertheless, faster techniques, including linear least‐squares (LLS) and Patlak graphical method, have been proposed to deal with high resolution noisy data, representing a more adaptable solution for routine clinical implementation. Former research investigating the relative performance of the available algorithms lack precise evaluation of kinetic parameter estimates under realistic acquisition conditions. Methods: The present study aims at the systematic comparison of the feasibility and pertinence of kinetic modeling of dynamic cerebral 18F‐FDG PET using NLS, LLS, and Patlak method, based on numerical simulations and patient data. Numerical simulations were used to study the bias and variance of K1 and Ki parameters estimation under representative noise levels. Patient data allowed to assess the concordance between the three methods at the regional and voxel scale, and to evaluate the robustness of the estimations with respect to patient head motion. Results and Conclusions: Our findings indicate that at the regional level NLS and LLS provide kinetic parameter estimates (K1 and Ki) with similar bias and variance characteristics (K1 bias ± relative standard deviation [RSD] 0.0 ± 5.1% and 0.1% ± 4.9% for NLS and LLS respectively, Ki bias ± RSD 0.1% ± 4.5% and −0.7% ± 4.4% for NLS and LLS respectively). NLS estimates appear, however, to be slightly less sensitive to patient motion. At the voxel level, provided that patient motion is negligible or corrected, LLS offers an appealing alternative solution for local K1 mapping. It yields K1 estimates that are highly correlated, with high correlation with NLS values (Pearson's r = 0.95 on actual data) within computations times less than two orders of magnitude lower. Last, Patlak method appears as the most robust and accurate technique for the estimation of Ki values at the regional and voxel scale, with or without head motion. It provides low bias/low variance Ki quantification (bias ± RSD −1.5 ± 9.5% and −4.1 ± 19.7% for Patlak and NLS respectively) as well as smooth parametric images suitable for visual assessment. [ABSTRACT FROM AUTHOR]

Summary: This paper concentrates on the robust stabilization of fractional‐order plant suffering from general interval uncertainties by using fractional‐order controllers. General interval uncertainties mean that the coefficients and orders of the denominator and nominator of the fractional‐order plant are all uncertain and lie in specified intervals. Two main contributions are presented, as follows. (i) Based on a graphical method, a necessary and sufficient criterion is proposed for the stabilization of the general interval fractional‐order plant. By adopting some well‐defined multivalue functions, the proposed method can explicitly construct the nonconvex boundary of the value set of the fractional system. (ii) Two alternative methods are presented to improve the computational efficiency of the stabilization test. Based on a newly developed redundancy elimination technique, the first method can avoid computing and plotting many segments, which are in the interior of the value set of the fractional system. The second method utilizes a novel convex polygon bounding approach. It can efficiently construct a convex polygon to bound the nonconvex value set of the general interval fractional system. Examples are followed to illustrate the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

We present a new seed dormancy classification scheme for the non-deep level of the class physiological dormancy ( PD), which contains six types. Non-deep PD is divided into two sublevels: one for seeds that exhibit a dormancy continuum (types 1, 2 and 3) and the other for those that do not exhibit a dormancy continuum (types 4, 5 and 6). Analysis of previous studies showed that different types of non-deep PD also can be identified using a graphical method. Seeds with a dormancy (D) ↔ conditional dormancy ( CD) ↔ non-dormancy ( ND) cycle have a low germination percentage in the early stages of CD, and during dormancy loss the germination capacity increases. However, seeds with a CD/ ND ( i.e. D→ CD↔ ND) cycle germinate to a high percentage at a narrow range of temperatures in the early stages of CD. Cardinal temperatures for seeds with either a D/ ND or a CD/ ND cycle change during dormancy loss: the ceiling temperature increases in seeds with Type 1, the base temperature decreases in seeds with Type 2 and the base and ceiling temperatures decrease and increase, respectively, in seeds with Type 3. Criteria for distinguishing the six types of non-deep PD and models of the temperature functions of seeds with types 1, 2 and 3 with both types of dormancy cycles are presented. The relevancy of our results to modelling the timing of weed seedling emergence is briefly discussed. [ABSTRACT FROM AUTHOR]

This article presents a graphical tool for the monitoring of performance indicators called GAOEM (Graphical Analysis for Overall Effectiveness Management). GAOEM comprehends the main indicators of maintenance and operations management, and it constitutes an adaptation of the overall effectiveness index. GAOEM facilitates control and analysis by using specific indicators in a graphic panel, designed for industries with high investment in physical assets. It also facilitates an efficient reading and interpreting of the data, enriching the analysis, the search for phenomena of interest and improvement opportunities to support the decision making. GAOEM requires 3 categories of input data, which are interventions data, time data, and production/process data. With this information, the basic performance indicators are calculated, being these indicators fundamental for the control and monitoring of the performance level. Later, these indicators will be the basis for calculation of both partial and total performance. GAOEM can be used as a diagnosis, analysis, control and monitoring tool for the indicators of interest at a strategic level, as well as a tool for searching of phenomena typical of a specific stage of the life cycle of assets and also of those conditions resulting from improper operation and/or maintenance, identifying their root causes. [ABSTRACT FROM AUTHOR]

This paper proposes a graphical method to easy decision-making in industrial plants operations. The proposed tool 'Graphical Analysis for Operation Management (GAOM) method' allows to visualizing and analyzing production-related parameters, integrating assets/systems maintenance aspects. This integration is based on the Total Productive Maintenance model, using its quantitative management techniques for optimal decision-making in day-to-day operations. On the one hand, GAOM monitors possible production target deviations, and on the other, the tool illustrates different aspects to gain control on the production process, such as availability, repair time, cumulative production, or overall equipment effectiveness. Through appropriate information filtering, individual analysis by class of intervention (corrective maintenance, preventive maintenance, or operational intervention) and production level can be developed. Graphical Analysis for Operation Management (GAOM) integrates maintenance information (number of intervention, type of intervention, required/not required stoppage) with production information (cumulative production, cumulative defective products, and cumulative production target) during a certain timeframe (cumulative calendar time, duration of intervention). Then the tool computes basic performance indicators supporting operational decision-making. GAOM provides interesting graphical outputs using scatter diagrams integrating indicators on the same graph. GAOM is inspired in the Graphical Analysis for Maintenance Management method, published by the authors (LB, AC, and PV) in 2012. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A graphical analysis to elucidate the order in catalyst is presented. This analysis uses a normalized time scale, t [cat]T n, to adjust entire reaction profiles constructed with concentration data. The method is fast and simple to perform because it directly uses the concentration data, therefore avoiding the data handling that is usually required to extract rates. Compared to methods that use rates, the normalized time scale analysis requires fewer experiments and minimizes the effects of experimental errors by using information on the entire reaction profile. [ABSTRACT FROM AUTHOR]

A graphical analysis to elucidate the order in catalyst is presented. This analysis uses a normalized time scale, t [cat]T n, to adjust entire reaction profiles constructed with concentration data. The method is fast and simple to perform because it directly uses the concentration data, therefore avoiding the data handling that is usually required to extract rates. Compared to methods that use rates, the normalized time scale analysis requires fewer experiments and minimizes the effects of experimental errors by using information on the entire reaction profile. [ABSTRACT FROM AUTHOR]

Chemical compositions of 80 vegetable oils were collected from literature and the properties of the obtainable biodiesel (methyl esters) have been predicted by empirical relationships. The purpose has been to check the viability of predicting if a biodiesel could meet the EN 14214 standards knowing only the fatty acid profile (FAP) of the parent oil. Two parameters were used in this investigation: (i) average number of carbon atoms in the fatty acid chains, (ii) average number of double bonds (CC) per molecule. Two new empirical relationships have been proposed to predict the viscosity and the cetane number of biodiesel from the two parameters. The range of values of the two parameters leading to biodiesel meeting the EN 14214 standard for viscosity, cetane number, iodine value, and cold filter plugging point have been graphically obtained by overlapping the corresponding level surfaces. Practical applications: This work provides biodiesel producers with indications of the quality of biodiesel without the need for analytical testing of the product (indeed, of the product itself). Only the fatty acid profile of the starting vegetable oil is required. The quality of biodiesel can be estimated by using a chart developed in this work, allowing to estimate, e.g. if the biodiesel meets the European standards. The work can be useful to rapidly screen oil seed crops in studies of genetic engineering that require high throughput. [ABSTRACT FROM AUTHOR]

A 3D graphical representation of DNA sequences, which has no circuit or degeneracy, is derived for mathematical denotation of DNA sequence. Based on this graphical representation, we propose a new sequence distance measure. We make use of the corresponding similarity matrix to construct a phylogenic tree by virtue of the fuzzy theory. The examination of phylogenic tree belong to eight species illustrates the utility of our approach. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [ABSTRACT FROM AUTHOR]

The article analyses a Cockcroft-Walton circuit by graphical model. Many kinds of condenser diode voltage multipliere have been proposed so far, but the design procedures have been discussed little. An effective method is proposed to analyze the behavior of the Cockcroft-Walton circuit. This method makes it possible to calculate the output voltage much more accurately than the conventional design formulas. The proposed method would be useful for various circuits other than the Cockcroft-Walton circuit.

Describes a factorial method for the graphical representation of ecological data which was originally designed for the mapping of biological activity spectra of drugs. Multivariate Ratio Analysis (MRA); Advantage of MRA over other methods.

This paper develops a general and complete solution for the undrained cylindrical cavity expansion problem in nonassociated Mohr‐Coulomb soil under nonhydrostatic initial stress field (i.e., arbitrary K0${{K}_0}$ values of the earth pressure coefficient), by expanding a unique and efficient graphical solution procedure recently proposed by Chen and Wang in 2022 for the special in situ stress case with K0=1${K}_{0}=1$. It is interesting to find that the cavity expansion deviatoric stress path is always composed of a series of piecewise straight lines, for all different case scenarios of K0 being involved. When the cavity is sufficiently expanded, the stress path will eventually end, exclusively, in a major sextant with Lode angle θ in between 5π3$\frac{{5\pi }}{3}$ and 11π6$\frac{{11\pi }}{6}$ or on the specific line of θ=11π6$\theta = \frac{{11\pi }}{6}$. The salient advantage/feature of the present general graphical approach lies in that it can deduce the cavity expansion responses in full closed form, nevertheless being free of the limitation of the intermediacy assumption for the vertical stress and of the difficulty existing in the traditional zoning method that involves cumbersome, sequential determination of distinct Mohr–Coulomb plastic regions. Some typical results for the desired cavity expansion curves and the limit cavity pressure are presented, to investigate the impacts of soil plasticity parameters and the earth pressure coefficient on the cavity responses. The proposed graphical method/solution will be of great value for the interpretation of pressuremeter tests in cohesive‐frictional soils. [ABSTRACT FROM AUTHOR]

In this work, an approximate analytical solution (AS) is presented to evaluate the radiative thermal exchange through a gaseous participating medium composed of H2O, CO2, and CO, which is valid for the product values of pressure path‐length (PL) from 0.06 to 20 atm m and temperatures (T) from 300 K to 2100 K. The Spence root weighting method is used to approximate the exact solutions. For each set of PL;T $\mathrm{PL}{\rm{;}}T$, the value of exact spectral emissivity and absorptivity ελ ${\varepsilon }_{\lambda }$ and aλ ${a}_{\lambda }$ for the gas mixture is calculated using the AS, the Hottel graphical method (HGM) and the proposed approximate solution. The weaker adjustment was achieved in the modeling of the HGM, with a mean deviation obtained of ±15% and ±20% for 43.8% and 56.3% of the data evaluated, respectively, while the best indices were obtained in the estimation of the proposed method, with a mean deviation obtained of ±10% and ±15% for 81.3% and 98.1% of the available data, respectively. In all cases, the agreement of the proposed model with the available experimental data is good enough to be considered satisfactory for practical design. [ABSTRACT FROM AUTHOR]

This article presents a graphical method to visually analyze the trait–yield association (TYA) patterns based on data from multi‐location, multi‐year crop variety trials, exemplified using oat data from trials conducted across Canada from 2017 to 2022. Each year a new set of 60–66 oat (Avena sativa L.) breeding lines were tested in replicated yield trials at 9–11 locations, and data for yield, key agronomic and quality traits, and crown rust scores were collected at all or some of the locations. Pearson correlation coefficient was calculated between yield and each trait for each trial. The correlation coefficients from different locations and years were arranged in a TYA × trial (TYT) two‐way table. This table was subjected to singular value decomposition, and the resulting first two principal components were used to generate a TYT biplot. The TYT biplot revealed three oat mega‐environments (MEs) in Canada, consistent with the conclusion from previous ME analyses, indicating that each ME had its characteristic TYA patterns. It was found that yield was consistently and positively correlated with crown rust (Puccinia coronata var. avenae) resistance, test weight, kernel weight, and groat content in ME1 (the crown rust‐prone regions of Ontario); yield was correlated positively with plant height but negatively with oil content in ME2 (the northern regions of eastern Canada). Interestingly, crown rust resistance was found to contribute negatively to yield in ME2. No strong and consistent TYAs were found in ME3 (the Canadian prairies). Different types of TYAs have different uses in genotypic selection. Core Ideas: A trait–yield association × trial (TYT) biplot was introduced to reveal trait–yield association patterns.TYT biplots revealed different oat mega‐environments in Canada, each with unique trait–yield association patterns.Trait–yield association patterns can be used to guide visual selection.Crown rust resistance was shown to be counterproductive in the non‐rust regions.Different types of trait–yield associations have different uses in genotypic selection. [ABSTRACT FROM AUTHOR]

This paper presents analytical solutions for the finite expansion problems of a spherical or cylindrical cavity, using a simple yet novel graphical approach recently proposed by Chen & Abousleiman in 2022, in both original Cam Clay (OCC) and modified Cam Clay (MCC) soils under undrained conditions. It is shown that, for a soil mass subjected to isotropic in situ stress conditions, the stress paths in the deviatoric plane for the spherical and cylindrical cavity expansions turn out to be two straight lines, which correspond to Lode angles equal to 11π6$\frac{{11\pi }}{6}$ and 5π3$\frac{{5\pi }}{3}$, respectively. The desired limiting cavity pressure therefore can be directly and accurately evaluated through simple numerical integration with respect to the mean effective stress, while the relationship between the internal cavity pressure and the cavity radius, the cavity expansion curve, may be equally conveniently determined. Numerical results obtained from the current graphical method, for a range of the values of over consolidation ratio considered, compare extremely well with those from the conventional semianalytical formulations of the undrained cavity problem that involve solving a system of coupled governing differential equations. It is interesting to note that the representative and approximate solution developed by Collins & Yu in 1996 indeed is a correct one for the spherical cavity expansion problem, and, with minor modifications, will be applicable for the accurate calculation of the responses of the cylindrical cavity as well. [ABSTRACT FROM AUTHOR]

Permeate recovery is a key parameter that plays a central role in the performance assessment and optimization of reverse osmosis processes. It remains a great challenge for engineers in the field to determine the recovery conveniently and accurately from the basic parameters of a membrane system. A concise analytical model is presented here that, without the need for the empirical or fitting coefficients and tedious numerical calculation, links the recovery of a reverse osmosis process rigorously to three basic parameters: the feed water salt concentration, the characteristic of membrane process, and the driving pressure. A graphical solution method to the model is also introduced to find out the recovery effortlessly. The concise model and graphical method are demonstrated under various conditions as a powerful tool for the performance simulations and improvement of reverse osmosis processes. Practitioner Points: A concise model is presented for permeate recovery in an ideal RO desalination system.The recovery of an RO system is analytically related to a few system parameters.A graphical solution method is introduced to find out the explicit recovery.The ideal RO model can be a powerful tool for simulation of RO processes. [ABSTRACT FROM AUTHOR]

The fanning compression stress pattern in RC deep beams under uniform load presents a challenge to formulating the configuration of strut‐and‐tie model (STM). To this end, this paper proposes an alternative method for creating a graphical discontinuous stress field model (DSFM) to fill up the whole beam continuum. It comprises a certain number of trapezoidal stress‐bands with varying bandwidths, and their stress values can be calculated based on force equilibrium conditions. Several stress subfields are defined through a certain stress combination from several directions. The DSFM is implementable for both service limit state (SLS) and ultimate limit state (ULS) in that its configuration is primarily oriented by elastic stress field and only a limited plastic redistribution is allowed for plastic failure. The graphical procedure of DSFM is demonstrated and examined by a test deep beam example, which shows that the predictions are fairly in good agreement with the test results. [ABSTRACT FROM AUTHOR]

The ion mobility and ion density are key physical parameters in research of ion flow field of high‐voltage DC (HVDC) transmission lines. The Gerdien tube is one of the practical tools that can be utilised in situ measurement of ion mobility and ion density of coronated lines. The mobility spectrum, connecting the ion mobility and ion density, is an effective approach in analysis of the characteristics of corona ions and the effects of environmental factors on them. In previous studies, single measurement‐electrode Gerdien tube is frequently used to get the mobility of one single ion via graphical method or the total ion density when the tube is operating as a counter. To enable it to obtain the ion mobility spectrum, a method is devised by the analysis of graphical method and the transition phenomenon in current–voltage characteristics of the tube. Furthermore, the method is applied to the raw data of current–voltage characteristics published in the literatures. The ion mobility spectra are obtained and compared with those having been reported. By doing this, the method is validated. This new approach makes applications of Gerdien tubes more advantages in experimental researches of ion flow field of HVDC transmission lines. [ABSTRACT FROM AUTHOR]

We represent the dynamic relation among variables in vector autoregressive (VAR) models as directed graphs. Based on these graphs, we identify so‐called strongly connected components. Using this graphical representation, we consider the problem of variable choice. We use the relations among the strongly connected components to select variables that need to be included in a VAR if interest is in impulse response analysis of a given set of variables. Our theoretical contributions show that the set of selected variables from the graphical method coincides with the set of variables that is multi‐step causal for the variables of interest by relating the paths in the graph to the coefficients of the 'direct' VAR representation. An empirical application illustrates the usefulness of the suggested approach: Including the selected variables into a small US monetary VAR is useful for impulse response analysis as it avoids the well‐known 'price‐puzzle'. [ABSTRACT FROM AUTHOR]

The selection based on multiple traits enhances the crop cultivars merit to farmers. In this regard, 19 breeding lines as well as two commercial cultivars were studied using a randomized complete block design (RCBD) with three replications in three locations during the 2020–2021 growing season. In this study, to identify the association among different traits and to select the best rapeseed lines based on multiple traits, genotype × trait (GT) and genotype × yield × trait (GYT) biplot analyses were used. The results showed that using GYT biplot is more efficient than GT biplot. Based on the GYT biplot and superiority index (SI), the breeding lines G16 and G18 were considered as superior genotypes in combination with the agronomical traits, that is, 1000‐seed weight, number of seeds per pod, number of pods per plant, number of lateral branches, plant height, and pod length with seed yield, which represents a genetic gain in rapeseed breeding program. Based on seed yield combination with phenological traits (early maturity), the breeding line G15 was selected as the best one. Moreover, the line G2 was defined as the superior one in combination of seed yield with pod length. The results indicated that there is a potential for simultaneous genetic improvement of the characteristics (i.e., plant height, number of seeds per pod, early maturity) in rapeseed. Generally, the graphical method of the GYT biplot represented an efficient and practical new way to recognize superior genotypes based on multiple traits in rapeseed breeding programs. [ABSTRACT FROM AUTHOR]

Actuator rate limit phenomenon is ubiquitous in control systems, but it has always been neglected in practical engineering. Especially, few papers are published to investigate the system identification while considering the rate limit. Step function is commonly used in parameter estimation and its first‐order derivative at the step time goes to infinity, which is not affordable by real actuators. As a result, the rate limit slows down the system response speed, misleads the parameter identification, and subsequently affects the controller design and deteriorates the control performance. This study proposes both graphical method and curve fitting method to identify the first‐order plus time‐delay (FOPTD) systems with consideration of the actuator rate limit effect whose limit value is unknown. Quantitative analyses of the parameter mismatch in the traditional FOPTD model and parameter sensitivity analyses are also carried out. Both simulation results and experimental results have shown the necessity and feasibility of defining a new model structure which includes the rate limit value. [ABSTRACT FROM AUTHOR]

Bio‐oils such as conventional soybean, high‐oleic soybean, canola, and sunflower are valuable as bio‐solvents for removing hydrogen sulfide (H2S) from natural gas. Preceding bench‐scale studies indicate that more than 90% of H2S can be removed from a gas stream; economic analysis of such a process is necessary to determine the solvent regenerative power required and cost constraints on a to‐be‐determined solvent regeneration scheme. With the goal of processing 1000 kmol·h–1 of sour gas and removing 99.9% of H2S from gas streams with various feed concentrations, the design of an absorption unit to process natural gas using bio‐oils as the absorbing solvent was carried out through equilibrium stage analysis. A graphical method combined with the Kremser method found that a trayed tower with 14 stages, a 2 m diameter, and 8.5 m height could meet these goals successfully with a bio‐solvent flow rate of 120 kmol·h–1. Capital costs were centered on the price of an extraction column designed to meet the desired throughput. Comparison with conventional amine gas treatment was used to set a limit for the cost of treating a unit of gas, and sensitivity analysis explored the relationship between solvent recycle and cost of treating the gas. This study found that the economic viability of using bio‐oils as gas‐sweetening agents depended on developing a solvent regeneration scheme capable of recycling more than 98% of the bio‐oil bio‐solvent. The development of such a scheme is unlikely, and the overall process of using bio‐oils to sweeten sour gas is likely not economically viable. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Germination timing is an important determinant of survival and niche breadth of plants. The annual plant Nigella sativa occurs in diverse environments along a steep temperature gradient and thus is a suitable model for the study of germination behavior in response to temperature. We used a modeling approach to compare the germination thermal niche of seeds of nine populations of N. sativa produced in a common garden. Germination time courses were obtained by a newly developed process‐based model, and thermal niche was visualized by plotting germination breadth as a function of after‐ripening time. Seeds were sampled five times: immature (2 weeks before maturity), mature, and afterripened for 1, 2, and 5 months. Immature and mature seeds had a greater depth of dormancy than afterripened seeds, as estimated by lower values of high‐limit temperatures (Th). Afterripening increased germination percentage, synchrony, and thermal niche breadth of all nine populations. The highest asynchrony was for immature and mature seeds, and afterripening enhanced synchrony. Based on the new graphical method, N. sativa has Type 1 nondeep physiological dormancy, and thus, the germination niche is narrow at seed maturity, leading to a delayed germination strategy that is highly dependent on thermal time accumulated during afterripening. Our findings show that there is considerable variation in the germination thermal niche among populations. Temperature regimes in the natural habitats of N. sativa have played a significant role in shaping variation in thermal niche breadth for seed germination of this annual species. The models used in our study precisely predict germination behavior and thermal niche under different environmental conditions. The germination synchrony model also can estimate germination pattern and degree of dormancy during the year, suggesting a useful method for quantification of germination strategies. [ABSTRACT FROM AUTHOR]

X‐ray third‐order nonlinear asymmetrical diffraction has three independent parameters: the asymmetry angle, the incident wave intensity and the deviation from the exact Bragg orientation. In contrast to the linear case, in the nonlinear case the total reflection region does not exist for all intensity values and asymmetry angles. Theoretical consideration leads to analytical conditions of the total reflection region, and the analysis can be carried out by a graphical method. An exact solution in the total reflection region is found. The numerical solutions of the third‐order nonlinear diffraction allow one to find the reflection curves for a fixed asymmetry angle or for a fixed intensity. For very large or very small asymmetry factors the third‐order nonlinear effects can be observed for beams with very low intensities. [ABSTRACT FROM AUTHOR]

The rate constant ratios of the consecutive chlorination of p‐xylene at 70oC in a gas–liquid semibatch reactor using molecular chlorine, dichloroethane as a solvent, and antimony pentachloride as a catalyst was investigated up to the fourth successive reaction (tetrachloro‐p‐xylene production). The rate ratios were determined with both mathematical expressions and a graphical method proposed recently in the literature by use of the maxima of the successive products. In addition, to this simple method that concerns only one pair of values of products (single‐point maximum approach), another novel method is proposed and successfully applied concerning many pairs of corresponding values of intermediate products (multiple points maximum approach). This latter method permits the estimation of uncertainties and propagation of uncertainties that proved the usefulness and the possibilities of determining the parameters based on special points of the kinetic dependencies. The rate ratios found for monochloro‐p‐xylene (2‐chloro‐p‐xylene), dichloro‐p‐xylene (the sum of 2,3‐dichloro‐p‐xylene and 2,5‐dichloro‐p‐xylene), trichloro‐p‐xylene (2,3,5‐trichloro‐p‐xylene), and tetrachloro‐p‐xylene (2,3,5,6‐tetrachloro‐p‐xylene) are k2/k1 = 0.09741, k3/k1 = 0.002685, and k4/k1 = 0.000499. The ratio of the dichloro‐isomers produced was also determined in the initial stages as 3.3 in favor of 2,5‐dichloro‐p‐xylene, which is reasonable since 2,3‐dichloro‐p‐xylene is highly hindered by the adjacent groups on the aromatic nucleus. Nevertheless, as the production of trichloro‐p‐xylene increased considerably, the proportion of 2,3‐dichloro‐p‐xylene gradually diminished down to complete disappearance. This is attributed to the ease of this isomer to be further chlorinated to trichloro‐product since its available free sites on the nucleus are less hindered compared to 2,5‐dichloro‐p‐xylene. The standard uncertainties of the rate constant ratios, the standard deviation of the means, as well as the expanded uncertainties of the means were calculated and proved statistically accepted. Finally, the propagation of uncertainties for the trichloro‐p‐xylene was estimated using the partial derivatives of this product for each of the rate constant ratios. [ABSTRACT FROM AUTHOR]

Feeding specialisations are known to play an important role in the ecology and evolution of many organisms. In this study, we performed a comparative analysis based on the data of the gut content of eight species of the genus Limia (family Poeciliidae) to explore the potential role of feeding ecology in the radiation of this genus in the Caribbean. We analysed the feeding strategies using the modified Costello's graphical method. In addition, we estimated the contribution of each food item to the diet by calculating the alimentary index of six different functional categories that summarised the variation in main type of consumed items. We also compared the niche breadth for all analysed species and the niche breadth variation between wet and dry seasons in four species we were able to sample in both periods of the year. Most of the analysed species showed preference for detritus and algae. Species that exhibited a more omnivorous diet such as L. versicolor and L. perugiae revealed moderate levels of consumption of terrestrial and aquatic invertebrates. Nonetheless, some species such as L. yaguajali and L. nigrofasciata showed specialisations towards detritus as the dominant food item found in the gut content analysis. In general, niche breadth values were higher in the wet season than in the dry period. Our study showed that the majority of species analysed tend to be feeding generalists, but some degree of specialisation occurs in some species from Hispaniola where the diversity of the genus Limia is remarkably higher compared to the rest of the Greater Antilles. [ABSTRACT FROM AUTHOR]

In this paper, the stability criteria are used to graphically determine the startup of oscillation in a Smith chart. This approach is suitable for slightly unstable circuits near the resonated frequency. In practice, an available design of a microwave two-port oscillator is presented here. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 19: 144–149, 1998. [ABSTRACT FROM AUTHOR]

Die Idee, Bewegungsprozesse anhand von Stabwerkmodellen zu analysieren (= dynamische Stabwerkmodelle), basiert auf der Kraftflussanalyse mittels Stabwerkmodellen in der Statik [1, 2] und erweitert die Anwendung auf komplette dynamische Prozesse. Bei Stabwerkmodellen handelt es sich um eine vektorielle Analyse, die an jedem Knoten eines Systems grafisch durchgeführt wird. Bilden die Vektoren ein geschlossenes Krafteck, ist der betrachtete Knoten im Gleichgewicht und es handelt sich um einen statischen Zustand. Bleibt das Krafteck jedoch offen, treibt die resultierende Kraft den Knoten an, d. h., sie beschleunigt ihn in Abhängigkeit zu seiner Masse. Im Bauwesen spielen dynamische Prozesse nicht nur bei menscheninduzierten Schwingungen oder Bauwerksschwingungen durch Erdbeben oder Wind eine Rolle. Auch bei dem Tragfähigkeitsverlust einzelner Bauteile eines statisch bestimmten oder überbestimmten Tragwerks oder Tragwerkteils lagern sich die inneren Kräfte um, wodurch das gesamte System oder Teilsysteme kinematisch werden können. Die nachfolgende Bewegung des Systems hält so lange an, bis das Tragwerk mit einer neuen Geometrie ein Gleichgewicht findet und damit wieder statisch bestimmt wird. Dynamic strut‐and‐tie models – a graphical method to analyse dynamic processes using the exemple of an arc with a tension cable The idea to analyse processes of movement by means of dynamic strut‐and‐tie models is based on the vectorial force flow analysis of static problems but expands its application to complete dynamic processes. A strut‐and‐tie model is a vectorial analysis of layouts and polygons of forces carried out graphically for each knot of a system. If the layout of the polygon of forces is closed, the knot analysed is in static equilibrium. If the polygon of forces is not closed, the knot will be accelerated by the resulting force depending on its mass. Analysing dynamic processes in building design does not only play an important role in case of human‐made vibrations or structural vibrations caused by earthquakes or wind. In addition to the usual problems a dynamic analysis may be carried out if the whole construction or individual components of the structure lose stability. If that happens, the internal forces of the structure come into a flow and the whole system or parts of it can possibly become kinematic. The following movement keeps going until the structure comes into a new static equilibrium with a new geometry. [ABSTRACT FROM AUTHOR]

Given that p‐xylene is an important chemical feedstock for many final products in the market from pesticides, pharmaceuticals, peroxides to dyes, its chlorinated derivatives are of interest in the chemical industry. In this paper, the rate constant ratios of the consecutive chlorination of p‐xylene at 70°C in a gas–liquid semibatch reactor using molecular chlorine and iron(III) chloride as a catalyst was investigated up to the fourth successive reaction (tetrachloro‐p‐xylene production). The ratios were determined with both mathematical expressions and a graphical method proposed recently in the literature by use of the maxima of the successive products. The ratios found for monochloro‐p‐xylene (2‐chloro‐p‐xylene), dichloro‐p‐xylene (the sum of 2,3‐dichloro‐p‐xylene and 2,5‐dichloro‐p‐xylene), trichloro‐p‐xylene (2,3,5‐trichloro‐p‐xylene), and tetrachloro‐p‐xylene (2,3,5,6‐tetrachloro‐p‐xylene) are k2/k1 = 0.295, k3/k1 = 0.0826, and k4/k1 = 0.00383. The ratio of the dichlo‐isomers produced was also determined as 2.12 in favor of 2,5‐dichloro‐p‐xylene, which is reasonable since 2,3‐dichloro‐p‐xylene is highly hindered by the adjacent groups on the aromatic nucleus. The existing knowledge found in the literature on the rate constant ratios of consecutive reactions was also extended in this paper with a new mathematical expression for the determination of the third stage product peak concentration. The standard uncertainties of the rate constant ratios, the standard deviation of the means, as well as the expanded uncertainties of the means, were calculated. Finally, the propagation of uncertainties for the trichloro‐p‐xylene was estimated using the partial derivatives of this product for each of the rate constants. [ABSTRACT FROM AUTHOR]

Cation exchange is one of the most important classes of reactions controlling the soil solution composition for major ions. Modeling ion‐exchange equilibria is complicated by ternary solid‐phase interactions. The present study alleges that spurious ternary‐interactions can be reported when dilution of the exchanging ions by other ions on the solid‐phase is not accounted for in models. Ion‐exchange equilibria data from the NH4+–Ca2+–K+–vermiculite system is used to demonstrate that previous reports of ternary interactions in this system are an artifact of how solid‐phase mole fractions are defined; what mathematicians call "compositional incoherence." A graphical method to distinguish the effects of dilution from real chemical interactions is presented using mole fractions renormalizing in the ternary system so that they are defined the same way as they are in binary systems. Potassium was shown to not influence NH4+–Ca2+ exchange on vermiculite when these corrections for solid‐phase dilution were used. Core Ideas: Spurious ternary chemical interactions can be found in ternary ion‐exchange data.Spurious interactions are caused by dilution in the solid phase.A method to eliminate spurious interactions in ion‐exchange is developed.No ternary interactions are in the NH4+–Ca2+–K+–vermiculite system. [ABSTRACT FROM AUTHOR]

The ion mobility and ion density are key physical parameters in research of ion flow field of high-voltage DC (HVDC) transmission lines. The Gerdien tube is one of the practical tools that can be utilised in situ measurement of ion mobility and ion density of coronated lines. The mobility spectrum, connecting the ion mobility and ion density, is an effective approach in analysis of the characteristics of corona ions and the effects of environmental factors on them. In previous studies, single measurement-electrode Gerdien tube is frequently used to get the mobility of one single ion via graphical method or the total ion density when the tube is operating as a counter. To enable it to obtain the ion mobility spectrum, a method is devised by the analysis of graphical method and the transition phenomenon in current-voltage characteristics of the tube. Furthermore, the method is applied to the raw data of current-voltage characteristics published in the literatures. The ion mobility spectra are obtained and compared with those having been reported. By doing this, the method is validated. This new approach makes applications of Gerdien tubes more advantages in experimental researches of ion flow field of HVDC transmission lines. [ABSTRACT FROM AUTHOR]

In this research, a binary mixture of Cyanex 302 (bis‐2,4,4 trimethylpentyl monothiophosphinic acid) and D2EHPA (di‐2‐ethylhexyl phosphoric acid) in kerosene was used for extracting neodymium from nitric acid medium. The different variables affecting the extraction of Nd(III) such as contact time, solution acidity, extractant concentration, and temperature were investigated. Stripping of neodymium ions from the loaded organic phase using HCl, HNO3, and H2SO4 for the re‐extraction of neodymium was also carried out. Results indicated that the most efficient reagent for the stripping of neodymium was nitric acid. The extraction reaction of neodymium with the synergistic mixture was determined using graphical method to be NdH5A2B6. The organo‐metallic complex containing neodymium was examined by Fourier Transform Infrared Spectroscopy (FT‐IR). The values of stoichiometric coefficients and thermodynamic parameters were calculated for this mixture. The extraction was an endothermic process, and the thermodynamic functions, ΔH and ΔS were determined to be 10.532 kJ/mol and −123.681 j/mol °K, respectively for the system under study. The Cyanex 302+D2EHPA system not only increased the extraction efficiency of neodymium but also improved the selectivity significantly. The separation factor of neodymium and praseodymium suggested that this mixture would be of practical value in the separation of neodymium. [ABSTRACT FROM AUTHOR]

This article presents a Python‐based package, ipyChord, to compute the 2D chord distribution function (CDF) from the small‐angle X‐ray scattering (SAXS) pattern from polymer materials with fiber‐symmetrical nanostructure. The program allows construction of a harmonized SAXS pattern from a raw SAXS pattern, by normalization of the incident‐beam intensity, absorption correction for sample thickness, masking blind areas on the detector, and filling in the shadow of the beamstop and its holder using symmetry operations. Patterns from modular detectors with inter‐module gaps can still be fully constructed satisfactorily after determining the optimized beam position and a radial basis function. A CDF pattern computed from the full SAXS pattern can be used to determine the domain size and its variability using a graphical method. An interface distribution function computed from Bonart's longitudinal projection or sliced from a CDF meridian can quantify differently stacked hard and soft domains. Two cases of the application of ipyChord are presented. The software is open source and available at https://github.com/isaxs/ipyChord. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive delay‐dependent stability analysis of a micro‐grid system with constant communication delays. First, an exact method that takes into account both gain and phase margins (GPMs) is proposed to determine stability delay margins in terms of system and controller parameters. The method implements an elimination procedure to transform transcendental characteristic equation into a standard polynomial of the crossing frequency. The real roots of this new standard polynomial exactly match with the purely imaginary roots (crossing frequencies) of the original characteristic equation with transcendental terms. Second, an effective and simple graphical method is implemented to compute all stabilising proportional integral (PI) controller gains for a given time delay. The approach is based on extracting stability region and the stability boundary locus in the PI controller parameter space having user defined GPMs, and relative stability. The time‐domain simulation studies indicate that the proposed schemes give better desired dynamic performance as compared with the recently developed schemes for micro‐grid with communication delays. [ABSTRACT FROM AUTHOR]

A funnel plot is a graphical method to evaluate health‐care quality by comparing hospital performances on certain outcomes. So far, in nephrology, this method has been applied to clinical outcomes like mortality and complications. However, patient‐reported outcomes (PROs; eg, health‐related quality of life [HRQOL]) are becoming increasingly important and should be incorporated into this quality assessment. Using funnel plots has several advantages, including clearly visualized precision, detection of volume‐effects, discouragement of ranking hospitals and easy interpretation of results. However, without sufficient knowledge of underlying methods, it is easy to stumble into pitfalls, such as overinterpretation of standardized scores, incorrect direct comparisons of hospitals and assuming a hospital to be in‐control (ie, to perform as expected) based on underpowered comparisons. Furthermore, application of funnel plots to PROs is accompanied by additional challenges related to the multidimensional nature of PROs and difficulties with measuring PROs. Before using funnel plots for PROs, high and consistent response rates, adequate case mix correction and high‐quality PRO measures are required. In this article, we aim to provide insight into the use and interpretation of funnel plots by presenting an overview of the basic principles, pitfalls and considerations when applied to PROs, using examples from Dutch routine dialysis care. SUMMARY AT A GLANCE: The statistical review provides insights into the use and interpretation of funnel plots by presenting an overview of the basic principles, pitfalls and considerations when applied to patient‐reported outcomes using examples from Dutch routine dialysis care. [ABSTRACT FROM AUTHOR]

Purpose: Radiotherapy of solid tumors has been performed with various fractionation regimens such as multi- and hypofractionations. However, the ability to optimize the fractionation regimen considering the physical dose distribution remains insufficient. This study aims to optimize the fractionation regimen, in which the authors propose a graphical method for selecting the optimal number of fractions (n) and dose per fraction (d) based on dose-volume histograms for tumor and normal tissues of organs around the tumor. Methods: Modified linear-quadratic models were employed to estimate the radiation effects on the tumor and an organ at risk (OAR), where the repopulation of the tumor cells and the linearity of the dose-response curve in the high dose range of the surviving fraction were considered. The minimization problem for the damage effect on the OAR was solved under the constraint that the radiation effect on the tumor is fixed by a graphical method. Here, the damage effect on the OAR was estimated based on the dose-volume histogram. Results: It was found that the optimization of fractionation scheme incorporating the dose-volume histogram is possible by employing appropriate cell surviving models. The graphical method considering the repopulation of tumor cells and a rectilinear response in the high dose range enables them to derive the optimal number of fractions and dose per fraction. For example, in the treatment of prostate cancer, the optimal fractionation was suggested to lie in the range of 8-32 fractions with a daily dose of 2.2-6.3 Gy. Conclusions: It is possible to optimize the number of fractions and dose per fraction based on the physical dose distribution (i.e., dose-volume histogram) by the graphical method considering the effects on tumor and OARs around the tumor. This method may stipulate a new guideline to optimize the fractionation regimen for physics-guided fractionation. [ABSTRACT FROM AUTHOR]

Objective: A direct causal relationship of cerebrovascular risk factors/stroke to amyloid β (Aβ) deposition has yet to be shown. We conducted [11 C] Pittsburgh compound B (PiB)-positron emission tomography (PET) analysis on subacute ischemic stroke patients and healthy controls. We hypothesized that subacute ischemic stroke patients would show focal Aβ accumulation in cortical regions, which would increase and extend over time during the chronic phase after stroke onset.Methods: Patients were recruited 14 to 28 days after acute subcortical ischemic stroke and examined with [11 C]PiB-PET scans. Regional time-activity data were analyzed with the Logan graphical method. Whole brain voxel-based analysis was conducted to compare stroke patients with healthy controls. We also performed longitudinal comparison of patients with successive [11 C]PiB-PET scans 1 year after stroke.Results: Voxel-based analysis revealed a significant increase of [11 C]PiB-BPND of the precuneus/posterior cingulate cortex (PCu/PCC) in stroke patients at the subacute stage. Based on stepwise multiple regression analysis of [11 C]PiB-BP changes during follow-up as the dependent variable, years of education was the best independent correlate. There was a significant negative relationship between changes in [11 C]PiB-BP and years of education.Conclusions: Our results suggest that processes before and after the onset of ischemic stroke may trigger Aβ deposition in the PCu/PCC, whereby amyloid deposition begins at an early stage of Alzheimer's disease (AD). Our findings support the existence of a cooperative association between vascular risk factors/stroke and AD progression. Further, educational achievement had a protective effect against the increase in Aβ accumulation. [ABSTRACT FROM AUTHOR]

Fluorine‐18 labeled hydroxyphenethylguanidines were recently developed in our laboratory as a new class of PET radiopharmaceuticals for quantifying regional cardiac sympathetic nerve density in heart disease patients. Studies of 4‐[18F]fluoro‐m‐hydroxyphenethylguanidine ([18F]4F‐MHPG) and 3‐[18F]fluoro‐p‐hydroxyphenethylguanidine ([18F]3F‐PHPG) in human subjects have shown that these radiotracers can be used to generate high‐resolution maps of regional sympathetic nerve density using the Patlak graphical method. Previously, these compounds were synthesized using iodonium salt precursors, which provided sufficient radiochemical yields for on‐site clinical PET studies. However, we were interested in exploring new methods that could offer significantly higher radiochemical yields. Spirocyclic iodonium ylide precursors have recently been established as an attractive new approach to radiofluorination of electron‐rich aromatic compounds, offering several advantages over iodonium salt precursors. The goal of this study was to prepare a spirocyclic iodonium ylide precursor for synthesizing [18F]4F‐MHPG and evaluate its efficacy in production of this radiopharmaceutical. Under optimized automated reaction conditions, the iodonium ylide precursor provided radiochemical yields averaging 7.8% ± 1.4% (n = 8, EOS, not decay corrected), around threefold higher than those achieved previously using an iodonium salt precursor. With further optimization and scale‐up, this approach could potentially support commercial distribution of [18F]4F‐MHPG to PET centers without on‐site radiochemistry facilities. [ABSTRACT FROM AUTHOR]

The peculiarity of lidar systems is to provide profiles of optical properties of the atmosphere. The use of specific wavelengths and the selection of different kinds of backscattering (elastic, Raman, polarisation selective) permit to obtain information about suspended particles (aerosols). The authors show here a case study in which particle signals are detected from the boundary layer up to the stratosphere. Information on the size distribution of the different layers can be obtained, using a graphical method relying on the spectral dependence of aerosol extinction. The authors apply this method, for the first time to their knowledge, to stratospheric aerosol. [ABSTRACT FROM AUTHOR]

Background and Purpose: Neuroinflammation has been implicated in the pathophysiology of Parkinson's disease (PD), which might be influenced by successful neuroprotective drugs. The uptake of [11 C](R)-PK11195 (PK) is often considered to be a proxy for neuroinflammation, and can be quantified using the Logan graphical method with an image-derived blood input function, or the Logan reference tissue model using automated reference region extraction. The purposes of this study were (1) to assess whether these noninvasive image analysis methods can discriminate between patients with PD and healthy volunteers (HVs), and (2) to establish the effect size that would be required to distinguish true drug-induced changes from system variance in longitudinal trials.Methods: The sample consisted of 20 participants with PD and 19 HVs. Two independent teams analyzed the data to compare the volume of distribution calculated using image-derived input functions (IDIFs), and binding potentials calculated using the Logan reference region model.Results: With all methods, the higher signal-to-background in patients resulted in lower variability and better repeatability than in controls. We were able to use noninvasive techniques showing significantly increased uptake of PK in multiple brain regions of participants with PD compared to HVs.Conclusion: Although not necessarily reflecting absolute values, these noninvasive image analysis methods can discriminate between PD patients and HVs. We see a difference of 24% in the substantia nigra between PD and HV with a repeatability coefficient of 13%, showing that it will be possible to estimate responses in longitudinal, within subject trials of novel neuroprotective drugs. [ABSTRACT FROM AUTHOR]

Accuracy profile is a graphical method, which allows to validate an analytical method. It defines a validity of a concentration range for a given accuracy. With this tool, quantitative determinations of macroelements and microelements (Al, Ca, Fe, K, Mg, Mn, Na, P, S, and Zn) in plant samples were evaluated by the use of a wavelength‐dispersive X‐ray fluorescence instrument. The method uses a simple preparation procedure with only drying, grinding, and pressing samples. The measured samples were reference materials with known mineral contents. The calibration procedure was established by employing plant materials issued from interlaboratory studies. Matrix effects were corrected by employing the method of the influence coefficients on the basis of the computerized routine program linked to the equipment. The accuracy profiles of the method show the measurements (trueness and precision) collected under intermediate precision conditions and aim to compute an acceptability interval where a known proportion of future results will be located. The various types of accuracy profile behavior were exemplified. In comparison with an inductively coupled plasma optical emission spectrometry method, the use of X‐ray fluorescence offers a good alternative, faster, and better precision. Inversely, inductively coupled plasma optical emission spectrometry offers an approach well suited for the trueness of measurements with very low matrix effects. [ABSTRACT FROM AUTHOR]

Small animal positron emission tomography (PET) imaging allows in vivo quantification of lesion- or treatment-induced neurochemical changes in animal models of disease. Important for quantification are the kinetic modeling methods used to determine biologically-relevant parameters of tracer-tissue interaction. In this work, we evaluate modeling algorithms for the dopaminergic tracers 11C-dihydrotetrabenazine (DTBZ), 11C-methylphenidate (MP), and 11C-raclopride (RAC), used to image the dopaminergic system in the unilateral 6-hydroxydopamine lesioned rat model of Parkinson's disease. For the presynaptic tracers, PET measures are compared with autoradiographic binding measurements using DTBZ and [3H]WIN 35,428 (WIN). We independently developed a new variant of the tissue-input Logan graphical modeling method, and compared its performance with the simplified Logan graphical method and the simplified reference tissue with basis functions method (SRTM), for region of interest (ROI) averaged time activity curves (TACs) and parametric imaging. The modified graphical method was found to be effectively unbiased by target tissue noise and has advantages for parametric imaging, while all tested methods were equivalent for ROI-averaged data. Synapse 64:200-208, 2010. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Background: Sound evidence-based clinical and policy therapy recommendations depend on a process of acquiring literature, appraising it for study design and quality, and assessing its results in terms of relative benefits and harms. In this article we describe two summary metrics that have been developed to assist guideline developers to assess the importance of the quality/size of trials and the relative benefit and harm of treatments, and a related graphical method for displaying them together. Methods: To illustrate this graphic approach, we have used the evidence base for drug therapies for neuropathic pain. “Reliability” is calculated from the sample size and quality of trials, while the second metric, “Net Gain,” is calculated from the relative benefit and harm of each trial. Results: The graphical method differentiated the evidence for neuropathic pain drugs. Conclusions: This graphical output provides a simple and relatively easy way to understand summary of information on large amounts of trial data across a number of therapies, which may present an impression of the evidence at a glance even for a nonexpert. The usefulness of this graphical approach needs to be tested in the development of future clinical guidelines. [ABSTRACT FROM AUTHOR]

Dissolved gas analysis (DGA) is one of the most acceptable methods used for detecting and evaluating gases dissolved in mineral oil and also in the solid insulation of internal incipient faults in the power and distribution transformers based on the oil samples. DGA has been proved the most accurate method for condition assessment of power and distribution transformers. The fault types depend upon type and concentrations of each gas dissolved in oil. IEC, Rogers, Doernenburg and Duval techniques, in spite of their importance in diagnosing certain types of faults, do not consider the concentrations of carbon monoxide (CO) and carbon dioxide (CO2) to evaluate cellulose insulation degradation. Some of these techniques do not take into account the impact of ethane (C2 H6) and hydrogen (H2) for the evaluation of fault types. A new graphical method "Heptagon" based on seven gases produced in faulty transformer oil decomposition is presented. Based on about 452 test samples of transformer oil DGA, the Heptagon figure is drawn and the zones of different fault types are determined. The suggested technique is tested and compared with other techniques. [ABSTRACT FROM AUTHOR]

Design of experiments is a quality technology to achieve product excellence, that is to achieve high quality at low cost. It is a tool to optimize product and process designs, to accelerate the development cycle, to reduce development costs, to improve the transition of products from R & D to manufacturing and to troubleshoot manufacturing problems effectively. It has been successfully, but sporadically, used in the United States. More recently, it has been identified as a major technological reason for the success of Japan in producing high-quality products at low cost. In the United States, the need for increased competitiveness and the emphasis on quality improvement demands a widespread use of design of experiments by engineers, scientists and quality professionals. In the past, such widespread use has been hampered by a lack of proper training and a lack of availability of tools to easily implement design of experiments in industry. Three steps are essential, and are being taken, to change this situation dramatically. First, simple graphical methods, to design and analyse experiments, need to be developed, particularly when the necessary microcomputer resources are not available. Secondly, engineers, scientists and quality professionals must have access to microcomputer-based software for design and analysis of experiments.' Availability of such software would allow users to concentrate on the important scientific and engineering aspects of the problem by computerizing the necessary statistical expertise. Finally, since a majority of the current workforce is expected to be working in the year 2000, a massive training effort, based upon simple graphical methods and appropriate computer software, is necessary.2 The purpose of this paper is to describe a methodology based upon a new graphical method called interaction graphs and other previously known techniques, to simplify the correct design of practically important fractional factorial experiments. The essential problem in designing a fractional factorial experiment is first stated. The interaction graph for a 16-trial fractional factorial design is given to illustrate how the graphical procedure can be easily used to design a two-level fractional factorial experiment. Other previously known techniques are described to easily modify the two-level fractional factorial designs to create mixed multi-level designs. Interaction graphs for other practically useful fractional factorial designs are provided. A computer package called CADE (computer aided design of experiments), which automatically generates the appropriate fractional factorial designs based upon user specifications of factors, levels and interactions and conducts complete analyses of the designed experiments is briefly described. Finally, the graphical method is compared with other available methods for designing fractional factorial experiments. [ABSTRACT FROM AUTHOR]