Smaller Coefficient Of Variation Research Articles

Does aerobic capacity predict the spatial position of individuals within schools in juvenile qingbo (Spinibarbus sinensis)?

Schooling behavior is an adaptive trait of important biological and ecological significance in fish species. However, the question of how aerobic capacity and environmental factors (i.e., food and water velocity) affect the spatial positioning within fish schools has received little attention. Our study measured the aerobic capacity—as indicated by standard metabolic rate (SMR), maximum metabolic rate (MMR) and aerobic scope (AS)—and swimming performance of juvenile qingbo (Spinibarbus sinensis) and filmed their schooling behavior in a swim tunnel under both a control treatment and food stimulus treatment at three water velocities (20, 30 and 40cms−1). Neither aerobic capacity nor swimming performance was related to spatial position within schools. Food stimulation did not trigger any change in the characteristics of spatial position at three water velocities. However, an intra-school positional preference was found between water velocities under the control treatment and food stimulus treatment. Individuals who preferred the rear of the school had smaller coefficients of variation in position under the two treatments, but this behavior was not correlated with any parameters for metabolic rates. Inter-school social interaction level, as indicated by total chase times, was not affected by either water velocity or food appearance. Although aerobic capacity and food stimulus did not influence the spatial position of individuals within schools, individual qingbo had spatial positional preferences within schools between different water speeds.

Effects of the Fractional Laplacian Order on the Nonlocal Elastic Rod Response

Abstract In this paper, we yield with a nonlocal elastic rod problem, widely studied in the last decades. The main purpose of the paper is to investigate the effects of the statistic variability of the fractional operator order s on the displacements u of the rod. The rod is supposed to be subjected to external distributed forces, and the displacement field u is obtained by means of numerical procedure. The attention is particularly focused on the parameter s, which influences the response in a nonlinear fashion. The effects of the uncertainty of s on the response at different locations of the rod are investigated by the Monte Carlo simulations. The results obtained highlight the importance of s in the probabilistic feature of the response. In particular, it is found that for a small coefficient of variation of s, the probability density function of the response has a unique well-identifiable mode. On the other hand, for a high coefficient of variation of s, the probability density function of the response decreases monotonically. Finally, the coefficient of variation and, to a small extent, the mean of the response tend to increase as the coefficient of variation of s increases.

System reliability analysis and risk assessment of a layered slope in spatially variable soils considering stratigraphic boundary uncertainty

Due to complex geological deposition, post-deposition processes and limited site investigation data in engineering practice, soil properties are often spatially variable and the stratigraphic boundary in layered soils is generally characterized by uncertainty. The spatial variability of soil properties has been well investigated in past years, whereas the question of how the stratigraphic boundary uncertainty affects the slope stability remains unanswered. This paper attempts to investigate the effects of the stratigraphic boundary uncertainty on the system reliability and risk of a layered slope in spatially variable soils. In this paper, the spatial variability of soil properties is simulated by non-stationary random fields that are generated by an extended Cholesky decomposition technique, while the stochastic nature of the stratigraphic boundary location is simulated by a discrete random variable. Monte Carlo simulation (MCS) is suggested for evaluating the system failure probability and risk. Various comparisons between probabilistic analysis results obtained from considering and neglecting the stratigraphic boundary uncertainty have been made for different statistics of soil properties. Results show that the stratigraphic boundary uncertainty plays an important role in identifying the slope failure mechanism. Moreover, neglecting the stratigraphic boundary uncertainty would generally overestimate the slope failure risk for different statistics, except at small coefficients of variation of the friction angle, where the results are underestimated.

The Systematic Risk of Short-Sale Restrictions

In finance literature it is known that on a financial market in which short-selling of risky assets is restricted, the market portfolio is typically not efficient (see e.g. Fama and French (2004)). This paper analyses two different kinds of regulatory policies of short-sales on financial markets in which asset returns are given by an exogenously generated stochastic process. The first constraint allows investors short-selling of a reasonable size whereas the second prohibits short-selling of any size. For both policies a modified market portfolio is introduced. These portfolios are mean-variance efficient with the highest possible Sharpe ratio and satisfy the corresponding short-sale constraint. For both cases a time-dependent security market line is implemented which allows for a decomposition into systematic and non-systematic risk. It is shown that, from a viewpoint of a regulator, the restricted short-sale constraint is a more suitable regulatory policy. In contrast to the prohibited short-sale constraint, the restricted short-sale constraint, does not reduce the possibility of diversification. Hence, the portfolio return in this case has no diversifiable risk, a higher Sharpe ratio and a smaller coefficient of variation, which yields a smaller default risk, provided the return process is multivariate elliptically distributed.

The effect of random porosity field on supercritical carbonation of cement-based materials

In this paper, the supercritical carbonation process of cement-based materials is modelled by introducing a random porosity field to simulate the heterogeneous geometry of the carbonation profile. The suitability of two different random fields of porosity, based on the probability density function (PDF) and the ellipsoidal autocorrelation function (EAF) methods, are investigated, respectively, in simulating the distribution of porosity in cement mortar. After incorporating the above random fields into an established supercritical carbonation model, it is found that with some modifications, the EAF method with consideration of spatial correlation produces better simulation of the irregularities of the carbonation zones that have been observed from experimental results. It is also found that for given average porosity and coefficient of variation, the predicted average and maximum carbonation depths have much smaller coefficients of variation. The validated EAF supercritical carbonation model is then used in parametric studies that are conducted to assess the effect of various factors on the carbonation depth of the chemical process.

Regional stability analysis of Pseudostellariae Radix new variety "Shitai No.1"

To provide guidance for certification, popularization and application of Pseudostellariae Radix new variety, the regional adaptation and stabilities of "Shitai No.1" were evaluated. The "Qian taizishen No.1" and "SB-C" varieties (strains) were used as the control varieties. The agronomic, medicinal material traits and medicine quality were used as evaluation index to compare the phenotypic difference of the three varieties (strains) in four planting areas. Compared to the control varieties, 10 agronomic traits of "Shitai No.1" had the smallest coefficient of variation among the 18 agronomic traits, and other 8 agronomic traits placed the middle level. Among 8 medicinal material traits and medicine quality indicators, the coefficient of variation of different regions of the extract content, pseudostellarin B content, the number of 50 g root tuber, the plant medicinal materials weight and weight of single root of "Shitai No.1" were the smallest compare to other varieties (strains). It could be divided into three groups based on the phenotypic difference of the three varieties (strains) in four planting areas. The "Shitai No.1" was classified as one group, while the "Qian taizishen No.1" and "SB-C" had cross clustering. The regional stability of several index about agronomic traits, medicinal material traits and medicine quality of "Shitai No.1" were better than that of the control varieties (strains). "Shitai No.1" was suitable for planting, popularization and application in the appropriate ecological areas of Guizhou province.

Dose coefficients for ICRP reference pediatric phantoms exposed to idealised external gamma fields

Organ and effective dose coefficients have been calculated for the International Commission on Radiological Protection (ICRP) reference pediatric phantoms externally exposed to mono-energetic photon radiation (x- and gamma-rays) from 0.01 to 20 MeV. Calculations used Monte Carlo radiation transport techniques. Organ dose coefficients, i.e., organ absorbed dose per unit air kerma (Gy/Gy), were calculated for 28 organs and tissues including the active marrow (or red bone marrow) for 10 phantoms (newborn, 1 year, 5 year, 10 year, and 15 year old male and female). Radiation exposure was simulated for 33 photon mono-energies (0.01–20 MeV) in six irradiation geometries: antero-posterior (AP), postero-anterior, right lateral, left lateral, rotational, and isotropic. Organ dose coefficients for different ages closely agree in AP geometry as illustrated by a small coefficient of variation (COV) (the ratio of the standard deviation to the mean) of 4.4% for the lungs. The small COVs shown for the effective dose and AP irradiation geometry reflect that most of the radiosensitive organs are located in the front part of the human body. In contrast, we observed differences in organ dose coefficients across the ages of the phantoms for lateral irradiation geometries. We also observed variation in dose coefficients across different irradiation geometries, where the COV ranges from 18% (newborn male) to 38% (15 year old male) across idealised whole body irradiation geometries for the major organs (active marrow, colon, lung, stomach wall, and breast) at the energy of 0.1 MeV. Effective dose coefficients were also derived for applicable situations, e.g., radiation protection or risk projection. Our results are the first comprehensive set of organ and effective dose coefficients applicable to children and adolescents based on the newly adopted ICRP pediatric phantom series. Our tabulated organ and effective dose coefficients for these next-generation phantoms should provide more accurate estimates of organ doses in children than earlier dosimetric models allowed.

Speed of reversal of vecuronium neuromuscular block with different doses of neostigmine in anesthetized dogs

ObjectivesNeostigmine is routinely used to reverse non-depolarizing neuromuscular block. Given its indirect mechanism, a plateau may exist whereby increasing doses of neostigmine do not result in clinical benefit. This study was designed to measure the speed of reversal of vecuronium-induced neuromuscular block in isoflurane-anesthetized dogs after the administration of three doses of neostigmine as used in clinical practice. Study designProspective, crossover, randomized study. AnimalsSeven adult, mixed-breed dogs with a mean ± standard deviation (SD) age of 2.0 ± 0.8 years and weight of 19.1 ± 9.1 kg. MethodsDogs were anesthetized on three occasions with isoflurane and administered vecuronium (0.1 mg kg–1) intravenously (IV). The train-of-four (TOF) ratio was measured on the pelvic limb with acceleromyography. When the second twitch of the TOF had returned spontaneously, atropine (0.03 mg kg–1) and neostigmine (0.02, 0.04 or 0.07 mg kg–1) were administered IV. Time to reach a TOF ratio of ≥0.9 after neostigmine administration was recorded. ResultsIncreasing the dose of neostigmine from 0.02 mg kg–1 to 0.04 mg kg–1 and 0.07 mg kg–1 resulted in significant reductions in mean ± SD reversal times (10.5 ± 2.3, 7.4 ± 1.1 and 5.4 ± 0.5 minutes, respectively) (p < 0.0001) and smaller coefficients of variation (22%, 15% and 10%, respectively). Conclusions and clinical relevanceIncreasing the dose of neostigmine from 0.02 mg kg–1 to 0.04 mg kg–1 and 0.07 mg kg–1 produced faster and less variable reversal of vecuronium-induced neuromuscular block in isoflurane-anesthetized dogs. No ceiling effect was observed at this dose range.

Distribution of dead wood volume and mass in mediterranean Fagus sylvatica L. forests in Northern Iberian Peninsula. Implications for field sampling inventory

Aim of study: The aim of this study was to 1) estimate the amount of dead wood in managed beech (Fagus sylvatica L.) stands in northern Iberian Peninsula and 2) evaluate the most appropriate volume equation and the optimal transect length for sampling downed wood.Area of study: The study area is the Aralar Forest in Navarra (Northern Iberian Peninsula).Material and methods: The amount of dead wood by component (downed logs, snags, stumps and fine woody debris) was inventoried in 51 plots across a chronosequence of stand ages (0-120 years old).Main results: The average volume and biomass of dead wood was 24.43 m3 ha-1 and 7.65 Mg ha-1, respectively. This amount changed with stand development stage [17.14 m3 ha-1 in seedling stage; 34.09 m3 ha-1 inpole stage; 22.54 m3 ha-1 in mature stage and 24.27 m3 ha-1 in regular stand in regeneration stage], although the differences were not statistically significant for coarse woody debris. However, forest management influenced the amount of dead wood, because the proportion of mass in the different components and the decay stage depended on time since last thinning. The formula based on intersection diameter resulted on the smallest coefficient of variation out of seven log-volume formulae. Thus, the intersection diameter is the preferred method because it gives unbiased estimates, has the greatest precision and is the easiest to implement in the field.Research highlights: The amount of dead wood, and in particular snags, was significantly lower than that in reserved forests. Results of this study showed that sampling effort should be directed towards increasing the number of transects, instead of increasing transect length or collecting additional piece diameters that do not increase the accuracy or precision of DWM volume estimation.Keywords: snags; downed logs; stumps; fine woody debris; beech; line intersect sampling.

Production and verification of a 2nd generation clonal group of Japanese flounder, Paralichthys olivaceus

Clonal fishes are useful tools in biology and aquaculture studies due to their isogenicity. In Japanese flounder (Paralichthys olivaceus), a group of homozygous clones was created by inducing meiogynogenesis in eggs from a mitogynogenetic homozygous diploid. As the clones reached sexual maturity, meiogynogenesis was again induced in order to produce a 2nd generation clonal group of Japanese flounder. After 3 months, there were 611 healthy, surviving individuals. Twenty-four microsatellite markers, that covered all the linkage groups of Japanese flounder, were used to identify the homozygosity of the 2nd generation clones; no heterozygous locus was detected. This indicates that the production of a 2nd generation clonal group of Japanese flounder was successful. Restriction-site DNA associated sequencing at the genomic level also confirmed the homozygosity and clonality of the 2nd generation clonal group. Furthermore, these 2nd generation clones had a small coefficient of variation for body shape indices at 210 days of age and showed a high degree of similarity in body characteristics among individuals. The successful production of 2nd generation clones has laid the foundation for the large-scale production of clonal Japanese flounder.

Does the average JIF percentile make a difference?

Average journal impact factor (JIF) percentile is a novel bibliometric indicator introduced by Thomson Reuters. It's of great significance to study the characteristics of its data distribution and relationship with other bibliometric indicators, in order to assess its usefulness as a new bibliometric indicator. The research began by analyzing the meaning of average JIF percentile, and compared its statistical difference with impact factor. Based upon factor analysis, the paper used multivariate regression and quantile regression to study the relationship between average JIF percentile and other bibliometric indicators. Results showed that average JIF percentile had changed the statistical characteristic of impact factor, e.g. improved the relative value of impact factor, having smaller variation coefficient and distribution closer to normal distribution. Because it's non-parametric transformation, it cannot be used to measure the relative gap between journals; Average JIF percentile had the highest regression coefficient with journal impact, followed by timeliness and lastly the citable items; The lower the average JIF percentile, the higher the elastic coefficient of journal impact; When average JIF percentile was extremely high or extremely low, citable items were not correlated with the average JIF percentile at all; When average JIF percentile was low, elastic coefficient of timeliness was even higher; Average JIF percentile was not a proper indicator for multivariate journal evaluation; Average JIF percentile had both the advantages and disadvantages of impact factor, and thus had the same limitation in applying as the impact factor.

Evaluation of feed value of a by-product of pickled radish for ruminants: analyses of nutrient composition, storage stability, and in vitro ruminal fermentation

BackgroundBy-products of pickled radish (BPR) are considered food waste. Approximately 300 g/kg of the total mass of raw materials becomes BPR. Production of pickled radish has grown continuously and is presently about 40,000 metric tons annually in Korea. The objective of the present study was thus to explore the possibility of using BPR as a ruminant feed ingredient.ResultsBPR contained a large amount of moisture (more than 800 g/kg) and ash, and comprised mostly sodium (103 g/kg DM) and chloride (142 g/kg DM). On a dry matter basis, the crude protein (CP) and ether extract (EE) levels in BPR were 75 g/kg and 7 g/kg, respectively. The total digestible nutrient (TDN) level was 527 g/kg and the major portion of digestible nutrients was carbohydrate; 88 % organic matter (OM) was carbohydrate and 65 % of total carbohydrate was soluble or degradable fiber. The coefficient of variation (CV) of nutrient contents among production batches ranged from 4.65 to 33.83 %. The smallest CV was observed in OM, and the largest, in EE. The variation in CP content was relatively small (10.11 %). The storage stability test revealed that storage of BPR at 20 °C (room temperature) might not cause spoilage for 4 d, and possibly longer. If BPR is refrigerated, spoilage can be deferred for 21 d and longer. The in vitro ruminal fermentation study showed that substitution of annual ryegrass straw with BPR improved ruminal fermentation, as evidenced by an increase in VFA concentration, DM degradability, and total gas production.ConclusionThe major portion of nutrients in BPR is soluble or degradable fiber that can be easily fermented in the rumen without adverse effects, to provide energy to ruminant animals. Although its high sodium chloride content needs to be considered when formulating a ration, BPR can be successfully used as a feed ingredient in a ruminant diet, particularly if it is one component of a total mixed ration.

Volume resistivity of ultra-thin chopped carbon fiber tape reinforced thermoplastics

This study concerns the development of a reliable method to measure the volume resistivity of ultra-thin chopped carbon fiber tape reinforced thermoplastics (UT-CTT) made by tow spreading technology. It was found that, by using vises with aluminum foil and silver paste, resistivity can be accurately evaluated and the in-plane volume resistivity of UT-CTT decreased with increasing tape length and decreasing tape thickness. However, an increase in tape thickness led to a decrease in out-of-plane resistivity. The resistivity also had smaller coefficient of variation (CoV) in UT-CTT specimens that included a greater number of chopped tapes for a given volume. This makes it possible to achieve a volume resistivity in UT-CTT that is close to that of quasi-isotropic laminates, despite the discontinuity of the carbon fiber, with potential applications improving lightning resistance and electromagnetic interference (EMI) shielding.

Influence of Self-generated Anchors on the Voice Handicap Index-10 (VHI-10)

The aim of this research is to study whether the presentation of the Voice Handicap Index-10 questionnaire administered at the beginning of the treatment impinged on the results of the responses from the end of the treatment. The questionnaire was administered at the beginning of the treatment to a total of 308 patients. After the treatment, a group of 235 patients answered the questionnaire again without any reference to their responses on the initial administration. The other group of participants, consisting of 73 subjects, completed the questionnaire with the answer sheet of their initial self-assessment in sight. The data obtained show that patients who responded to the anchored answer test show less dispersion and a smaller coefficient of variation (0.90) than those who responded to the nonanchored answer test (coefficient of variation = 1.66). The method of administration of the Voice Handicap Index-10 at the end of a treatment influences the dispersion of the results. We recommend that the patient be anchored to the initial answer sheet while responding to the final self-assessment.

MEMD-enhanced multivariate fuzzy entropy for the evaluation of complexity in biomedical signals.

Multivariate multiscale entropy (mvMSE) has been proposed as a combination of the coarse-graining process and multivariate sample entropy (mvSE) to quantify the irregularity of multivariate signals. However, both the coarse-graining process and mvSE may not be reliable for short signals. Although the coarse-graining process can be replaced with multivariate empirical mode decomposition (MEMD), the relative instability of mvSE for short signals remains a problem. Here, we address this issue by proposing the multivariate fuzzy entropy (mvFE) with a new fuzzy membership function. The results using white Gaussian noise show that the mvFE leads to more reliable and stable results, especially for short signals, in comparison with mvSE. Accordingly, we propose MEMD-enhanced mvFE to quantify the complexity of signals. The characteristics of brain regions influenced by partial epilepsy are investigated by focal and non-focal electroencephalogram (EEG) time series. In this sense, the proposed MEMD-enhanced mvFE and mvSE are employed to discriminate focal EEG signals from non-focal ones. The results demonstrate the MEMD-enhanced mvFE values have a smaller coefficient of variation in comparison with those obtained by the MEMD-enhanced mvSE, even for long signals. The results also show that the MEMD-enhanced mvFE has better performance to quantify focal and non-focal signals compared with multivariate multiscale permutation entropy.

Unbiased estimation of Weibull modulus using linear least squares analysis—A systematic approach

The wide applicability of the Weibull distribution to fields such as hydrology and materials science has led to a large number of probability estimators being proposed, in particular for the widely used technique of obtaining the Weibull modulus, m, using unweighted linear least squares (LLS) analysis. In this work a systematic approach using the Monte Carlo method has been taken to determining the optimal probability estimators for unbiased estimation of m (mean, median and mode) using the general equation F=(i−a)/(N+b) whilst simultaneously minimising the coefficient of variation for each of the average values. A wide range of a and b values were investigated within the region 0≤a≤1 and 1≤b≤1000 with the form of F=(i−a)/(N+1) being chosen as the recommend probability estimator equation due to its simplicity and relatively small coefficient of variation. Values of a as a function of N were presented for the mean, median and mode m values.

Selecting series size where the generalized Pareto distribution best fits

Rates of arrival and magnitudes of hydrologic variables are frequently described by the Poisson and the generalized Pareto (GP) distributions. Variations of their goodness-of-fit to nested series are studied here. The variable employed is depth of rainfall events at five stations of the Israel Meteorological Service. Series sizes range from about 50 (number of years on records) to about 1000 (total number of recorded events). The goodness-of-fit is assessed by the Anderson-Darling test. Three versions of this test are applied here. These are the regular two-sided test (of which the statistic is designated here by A2), the upper one-sided test (UA2) and the adaptation to the Poisson distribution (PA2). Very good fits, with rejection significance levels higher than 0.5 for A2 and higher than 0.25 for PA2, are found for many series of different sizes. Values of the shape parameter of the GP distribution and of the predicted rainfall depths widely vary with series size. Small coefficients of variation are found, at each station, for the 100-year rainfall depths, predicted through the series with very good fit of the GP distribution. Therefore, predictions through series of very good fit appear more consistent than through other selections of series size. Variations of UA2, with series size, are found narrower than those of A2. Therefore, it is advisable to predict through the series of low UA2. Very good fits of the Poisson distribution to arrival rates are found for series with low UA2. But, a reversed relation is not found here. Thus, the model of Poissonian arrival rates and GP distribution of magnitudes suits here series with low UA2. It is recommended to predict through the series, to which the lowest UA2 is obtained.

Reproducibility of Neurochemical Profile Quantification in Pregenual Cingulate, Anterior Midcingulate, and Bilateral Posterior Insular Subdivisions Measured at 3 Tesla.

The current report assessed measurement reproducibility of proton magnetic resonance spectroscopy at 3 Tesla in the left and right posterior insular, pregenual anterior cingulate, and anterior midcingulate cortices. Ten healthy male volunteers aged 21–30 years were tested at four different days, of which nine were included in the data analysis. Intra- and inter-subject variability of myo-inositol, creatine, glutamate, total-choline, total-N-acetylaspartate, and combined glutamine–glutamate were calculated considering the influence of movement parameters, age, daytime of measurements, and tissue composition. Overall mean intra-/inter-subject variability for all neurochemicals combined revealed small mean coefficients of variation across the four regions: 5.3/9.05% in anterior midcingulate, 6.6/8.84% in pregenual anterior cingulate, 7.3/10.00% in left posterior and 8.2/10.55% in right posterior insula. Head movement, tissue composition and day time revealed no significant explanatory variance contribution suggesting a negligible influence on the data. A strong correlation between Cramer–Rao Lower Bounds (a measure of fitting errors) and the mean intra-subject coefficients of variation (r = 0.799, p < 0.001) outlined the importance of low fitting errors in order to obtain robust and finally meaningful measurements. The present findings confirm proton magnetic resonance spectroscopy as a reliable tool to measure brain neurochemistry in small subregions of the human brain.

39. CMAP area variability is a function of area size

We studied the relationship between CMAP area variability and CMAP area size in an experimental setting in which any other possible cause of variability was removed. In 10 normal volunteers we recorded from Abductor Digiti Minimi a CMAP of large area and one of small area simultaneously after maximal stimulation of the ulnar nerve at wrist. Ulnar nerve stimulation was repeated 5 times, 4-6 s apart, and two sets of 5 CMAPs were obtained: one of large area and one of small area. The same procedure was performed with stimulation of the ulnar nerve at the elbow. Non-polarizable, ring-shaped sintered Ag/AgCl Multitrode® surface electrodes were adopted. For each set of rectified responses (large and small) Coefficient of Variation (COV, %) was calculated. Areas and COVs from all subjects were expressed as mean ± SD. Mean intrasession variability of small CMAPs elicited at wrist was significantly greater than that of large CMAPs elicited at the same site (paired t test: p < 0.01). Variability was even slightly greater with stimulation at elbow. These results suggest the presence of component of variability unavoidable even under optimal recording conditions that partly varies as a function of the area, being significantly greater for smaller responses than for larger ones.

Hysteresis and Soil Site Dependent Input and Hysteretic Energy Spectra for Far-Source Ground Motions

Earthquake input energy spectra for four soil site classes, four hysteresis models, and five ductility levels are developed for far-source ground motion effect. These energy spectra are normalized by a quantity called velocity index (VI). The use of VI allows for the creation of dimensionless spectra and results in smaller coefficients of variation. Hysteretic energy spectra are then developed to address the demand aspect of an energy-based seismic design of structures with 5% critical damping and ductility that ranges from 2 to 5. The proposed input and hysteretic energy spectra are then compared with response spectra generated using nonlinear time history analyses of real ground motions and are found to produce reasonably good results over a relatively large period range.