bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sediment Phosphorus Extractants for Phosphorus‐31 Nuclear Magnetic Resonance Analysis
Authors: Ahlgren Joakim , De Brabandere Heidi , Reitzel Kasper , Rydin Emil , Gogoll Adolf , Waldebäck Monica 
Published: May 2007

AbstractThe influence of pre‐extractant, extractant, and post‐extractant on total extracted amounts of P and organic P compound groups measured with 31P nuclear magnetic resonance (31P‐NMR) in lacustrine sediment was examined. The main extractants investigated were sodium hydroxide (NaOH) and sodium hydroxide ethylenediaminetetraacetic acid (NaOH‐EDTA) with bicarbonate buffered dithionite (BD) or EDTA as pre‐extractants. Post extractions were conducted using either NaOH or NaOH‐EDTA, depending on the main extractant. Results showed that the most efficient combination of extractants for total P yield was NaOH with EDTA as pre‐extractant, yielding almost 50% more than the second best procedure. The P compound groups varying the most between the different extraction procedures were polyphosphates and pyrophosphates. NaOH with BD as pre‐extractant was the most efficient combination for these compound groups.
Reservoir Sedimentation and Environmental Degradation
Authors: Bennett Sean J. , Rhoton Fred E. 
Published: May 2007

AbstractSediments impounded within flood control reservoirs are potentially important archives of environmental and geomorphic processes occurring within drainage basins. The concentrations of select sediment‐associated trace elements were assessed within the impoundment of Grenada Lake, a relatively large flood control reservoir in Mississippi with a history of contaminant bioaccumulation in fish. The post‐construction sediments (after 1954) are discriminated from the pre‐construction sediments (before 1954) based on depth variations in sediment texture and 137Cs emissions. The concentrations of select trace elements of the post‐1954 sediments all are statistically greater than the pre‐1954 sediments, and these same sediments also are enriched in clay. Once these concentrations are normalized by clay content, all trace elements in the post‐1954 sediments are lower in concentration than the pre‐1954 normalized sediments. Moreover, the trace elements when normalized by clay or Al content show virtually no change vertically (over time) within the reservoir impoundment. This suggests that the sources of these sediment‐associated trace elements within Grenada Lake, whether natural or anthropogenic, have not changed appreciably over the lifespan of the reservoir and that the degradation of sedimentologic and ecologic indices within the lake are due to the sequestration of clay or clay‐sized materials.
Cut‐off Net Acid Generation pH in Predicting Acid‐Forming Potential in Mine Spoils
Authors: Liao B. , Huang L. N. , Ye Z. H. , Lan C. Y. , Shu W. S. 
Published: May 2007

AbstractAcidification of mine wastes can lead to a series of environmental problems, such as acid drainage, heavy metal mobilization, and ecosystem degradation. Prediction of acid‐forming potential is one of the key steps in management of sulfide‐bearing mine wastes. In this paper, the acid‐forming potential of 180 mine waste samples collected from 17 mine sites in China were studied using a net acid generation (NAG) method. The samples contained different contents of total sulfur (ranging from 0.6 to 200 g kg−1), pyritic sulfur (ranging from 0 to 100 g kg−1), and acid neutralization capacity (ANC, ranging from −41 to 274 kg H2SO4 t−1). Samples with high acid‐forming potential are generally due to their high sulfur content or low acid neutralization capacity. After the samples were oxidized by H2O2, the amounts of acid generation and the final NAG pH were measured. Results indicated that the final NAG pH gave a well‐defined demarcation between acid‐forming and non‐acid‐forming materials. Samples with final NAG pH ≥ 5 could be classified as non‐acid‐forming materials, while those with NAG pH ≤ 2.5 could be classified as moderate to strong acid‐forming materials. Materials with NAG pH > 2.5, but < 5, had low risk of being acid‐forming. The confirmation of cut‐off NAG pH will be used as a rapid and cost‐effective operational monitoring tool for the in‐pit prediction of acid‐forming potential of mine wastes and classification of waste types.
Discerning and Modeling the Fate and Transport of Testosterone in Undisturbed Soil
Authors: Fan Zhaosheng , Casey Francis X. M. , Hakk Heldur , Larsen Gerald L. 
Published: May 2007

AbstractTestosterone is an endocrine disruptor that is released into the environment from natural and anthropogenic sources. The objective of this study was to achieve a better understanding of the complex fate and transport of this labile compound in an undisturbed agricultural soil (a Hamar Sandy, mixed, frigid typic Endoaquolls). This was done by using batch and miscible‐displacement experiments, and by using a chemical nonequilibrium transport model. Sorption and transformations of testosterone were discerned using various batch experiments. The batch experiments indicated that the aqueous phase concentrations of testosterone rapidly decreased from 12 to 15% of the initial aqueous concentration within 5 h, but then gradually increased through time and reached 28 to 29% of the initial aqueous concentration at 168 h. The increase in the aqueous concentration was explained by mineralization and biodegradation. Multiple first‐order models were used to describe batch experiments where simultaneous degradation and sorption processes occurred. An evolutionary global optimization strategy was used to estimate the process parameters from these batch experiments and there was high confidence in these parameter estimates. The result of column experiments also showed that 23.4% of testosterone was mineralized to CO2 as it transported through the column. Combustion analyses of extracted soil from inside the columns showed that most of the 14C retained in the column (69–74%) was sorbed in the top 5 cm. The independently determined batch parameters were incorporated into a chemical nonequilibrium transport model, which provided an excellent description of the hormone in the effluent, and vertical redistribution in the soil column.
Ueber die Nachbildung der natürlichen Heilquellen
Authors: Struve F. A. A. 
Published: May 2007

Abstract[Die Mineralwässer haben in neuerer Zeit in Deutschland so mannichfache Erörterungen veranlasst und über sie sind zugleich so viele wunderliche Dinge unter das Publikum gebracht worden, dass es wohl ganz zeitgemäss ist, auch einmal hervorzuheben, was hinsichtlich eines der viel bestrittenen Punkte, nämlich der Entstehung der Mineralwässer, die Resultate einer mit Umsicht angestellten Experimentaluntersuchung gelehrt haben. Aus diesem Grunde habe ich mir erlaubt, aus dem so eben von Hrn. Dr. Struve herausgegebenen zweiten Hefte: Ueber die Nachbildung der natürlichen Heilquellen u. s. w., unter Mitwissen des geehrten Verfassers, einen Auszug in die Annalen aufzunehmen, und zwar in grösserer Ausführlichkeit, als es sonst bei einem für sich in deutscher Sprache erschienenen Werke geschehen wäre. Ich habe jedoch nur das herausgehoben, was mit dem genannten Gegenstande in unmittelbarer Beziehung steht, und überlasse den Lesern, die fernerweitigen interessanten Versuche und Betrachtungen des Verfassers im Originale selbst nachzusehen. Auch ist es hier wohl am Ort, die Leser auf die beiden schätzbaren Werke des Hrn. Prof. Bischof: Die Mineralquellen Deutschlands und Frankreichs u. s. w., und: Die Mineralquellen zu Roisdorf u. s. w. (beide Bonn 1826) aufmerksam zu machen, da sie in diesen Mehreres, was unser Verfasser bloss angedeutet hat, näher entwickelt und mit der nöthigen literarischen Nachweisung zusammengestellt finden.]
L1‐logistic Discrimination as Used for Assistance of Medical Diagnosis in Chronic Airways Disease
Authors: Krusińska E. , Liebhart J. 
Published: May 2007

AbstractThe paper presents an application of L1‐logistic discriminant functions to the support of medical diagnosis in so called chronic airways disease which includes bronchial asthma, chronic bronchitis and lung ephysema. It is shown that the L1‐logistic discriminant function is more robust than the classical logistic function and gives higher rate of correctly classified individuals.
A Global Rank Test for Geographical Clusters of Disease
Authors: Möhner M. 
Published: May 2007

AbstractIn the last years a considerable amount of effort has been put into the methodology of mapping and analysis of geographical distribution of cancer incidence or mortality. A test for geographical clusters, taking into account the rank order with respect to the cancer incidence was proposed in the Cancer Atlas of Scotland (KEMP et al. (1985)). But, unfortunately the test requires a time‐consuming simulation for the distribution function of the corresponding test statistics.In the present paper an easy calculable normal approximation of this rank‐test will be derived. A simulation study for two regions shows that the goodness of approximation is much better than it could be assumed by the corresponding bounds derived by the Berry‐Esseen‐inequality.
Approximate Confidence Interval on Ratio of Two Variances in a Two‐way Crossed Model
Authors: Ting Naitee , Graybill Franklin A. 
Published: May 2007

AbstractThe model considered is a two‐factor cross‐classification variance components model with one observation per cell. Let the two factors be A and B, the problem is to obtain an approximate confidence interval for the ratio of variance component A over variance component B. In this paper, a method of solving this problem is established and simulations are performed to check the method.
A Test for Detecting Overdispersion in Multiple Spell Failure Time Models
Authors: Hamerle A. 
Published: May 2007

AbstractThis paper proposes a test for the detection of the presence of unobserved heterogeneity. The term “unobserved heterogeneity” refers to differences remaining in hazard rates after controlling for the effects of the included covariates. The test relies on results of LANCASTER (1985), and BURDETT et al. (1985). Their results are generalized to allow for multiple spells. No assumption on the functional form of the distribution of the heterogeneity is required. The test statistic can be calculated with available computer programs. In the last section we present an example of the application of the test, analyzing survival data after breast cancer operation.
A Note on Estimation of Several Missing Values in Two Way Classified Data with Many Observations Per Cell
Authors: Subramani J. 
Published: May 2007

AbstractIn this paper an attempt has been made to reduce the computational complexities involved in estimation of several missing values. As a result it has been shown that one can estimate m missing values by developing only k (≤m) linear equations, where m and k are respectively the number of missing values and missing cells. The procedure is also illustrated with the help of a numerical example.
A Test of the Equivalence of Four Random Number Generators – A Simulation Study
Authors: Rovine Michael J. , von Eye Alexander , Jones Constance J. 
Published: May 2007

AbstractFour pseudo random number generators were tested for equivalence. Using two different seed values for each generator, the robustness of a one‐sample t‐statistic was assessed under a stationary auto‐regressive process. The degree of autocorrelation, sample size and significance level were varied for the eight sets of random numbers generated. Results showed an interaction effect between random number generator and alpha level of the t‐distribution, suggesting that simulation results could depend on the random number generator selected.
Reduction of Total Sample Size and Cost of Sampling in Tests of Hypothesis by Using Unequal Group Sizes
Authors: Trajstman A. C. 
Published: May 2007

AbstractThe standard approach in calculating the appropriate sample size required to detect a specified difference in the means of two populations for given type I and II errors assumes equal sample sizes in each group. It is shown here that equal sample sizes are usually sub‐optimal with respect to total sample size and with respect to total cost of the experiment. This is may be important in experiments involving animals when costs are measured not only in monetary terms but also in terms of animal suffering or inconvenience.
More Parsimonious Linar‐By‐Linear Associatin Model in the Analysis of Cross‐Classifications Having Ordered Categories
Authors: Tomizaawa Sadao 
Published: May 2007

AbstractFor the analysis of cross‐classifications having ordered categories, this paper proposes a model which is more parsimonious than the linear‐by‐linear association (LL) model (that is, which can be described in terms of fewer parameters than the LL model). In a special case, this model is more parsimonious than the uniform association (U) model. Under this model, the expected frequency on a log scale is a linear function of row and column variables for fixed column and row variables, respectively. For the well‐known operation and dumping severity data, the parsimonious U model proposed here fits well, and new interpretations are added.
A Booststrap Adaptive Test for Two‐way Analysis of Variance
Authors: Donegani M. 
Published: May 2007

AbstractWe propose a method to construct adaptive tests based on a bootstrap technique. The procedure leads to a nearly exact adaptive test depending on the size of the sample. With the use of the estimated Pitman's relative efficacy as selector statistic, we show that the adaptive test has a power that is asymptotically equal to the power of it's better component. We apply the idea to construct an adaptive test for two‐way analysis of variance model. Finally, we use simulations to observe the behaviour of the method for small sample sizes.
Response to Selection Under Non‐Random Mating I. Partitioning Genetic Variance
Authors: Muralidharan K. , Jain J. P. 
Published: May 2007

AbstractIn analogy to the concept of breeding value defined for random mating equilibrium populations, the “transmittable genetic value” of an individual is defined as the average value of its expected progeny for any system of mating. The genotypic value is then characterised in terms of transmittable and residual genetic values and components of genetic variance redefined which can be estimated by the conventional procedure based on resemblance between relatives.
On the Boundary Behaviour of Nonparametric Regression Estimators
Authors: Dette H. 
Published: May 2007

AbstractIn this note the nonparametric regression estimators of Nadaraya (1964) and Watson (1964), Priestley & Chao (1972) and Gasser & Müller (1979) are compared with respect to the boundary behaviour in the case of a fixed design. It is shown that the estimator of Nadaraya & Watson yields estimates with smaller mean squared error at the boundary in finite sample situations compared to the convolution type estimators. By a modification of the kernel function the estimator of Gasser & Müller attains a similar boundary behaviour as the Nadaraya & Watson estimator. The theoretical results are illustrated in a simulation study.
Phenotypic Correlation: Its Estimation and Testing Significance
Authors: Sing Murari , El‐Bizri Khaled S. 
Published: May 2007

AbstractPlant scientists often assess correlation coefficients to develope a selection strategy for better plant type. They generate data on the desired traits on several genotypes grown in a randomized complete block design. Using the data from such experiments, this paper presents the asymptotic standard error of an estimate of phenotypic correlations coefficient and a test of significance. The method is illustrated using data on chickpea crop.
Estimating Growth Reduction Dose for Polynomial Response Relationships
Authors: Singh M. , Haq M. A. 
Published: May 2007

AbstractMutation breeders often estimate an irradiation dose which causes a specified reduction in growth of a biological material. In this paper, we estimate the growth reduction dose (GRD) and its confidence interval, when the dose‐response relationship is of a general polynomial form. We make a realistic assumption that the response at the control dose is a random variable. We compare the estimates, standard error and confidence intervals of GRD with those obtained under a situation where response at control dose is a known constant. We illustrate the procedure with data on the effect of gamma irradiation and Ethylmethane sulphate on shoot lengths of chickpea genotypes.
Statistical Comparison of Band Spectral Power: An Aid in Stochastical Analysis of Brain Electrical Activity Part 1: Approximation of the distribution of broad band power by a χ2‐distribution
Authors: Schack B. , Wagner H. , Witte H. 
Published: May 2007

AbstractIn this study the distribution of estimated broad band spectral power is evaluated. Under weak assumptions it is possible to appropriate this distribution by a χ2‐distribution and to construct tolerance intervals with great statistical accuracy. The theoretical results implicate a new methodical basis for statistical comparison of spectral parameters in EEG analysis.
The Error Rate of Tests for Regression Coincidence and Parallelism Under Unknown Multiplicative Heteroscedasticity
Authors: Gregoire Timothy G. 
Published: May 2007

AbstractThe usualFtest of regression coincidence, which is appropriate under a homoscedastic model, is examined under a multiplicatively heteroscedastic model. The departure of the test from its nominal level is slight when the sample of explanatory variables is symmetric, but may be substantially inflated when the sample has positive skew. Conversely, the nominal level may be slightly depressed when the sample has negative skew. The size of the perturbation from the nominal level depends on the degree of heteroscedasticity, however its effect is more pronounced with positively skewed samples. Similar trends are evident for the usualFtest of regression parallelism. There is no apparent pattern to the discrepancy of the level of the test with regard to the data which would permit empirical researchers to adjust their results.
Use of Polytomous Logistic Model in Matched Case‐Control Studies
Authors: Ganguly S. S. , Nimbalkar U. Naik 
Published: May 2007

AbstractBinary logistic model has been found useful for estimating odds ratio in case of dichotomous exposure variable under matched case‐control retrospective design. We describe the use of polytomous logistic model for estimating odds ratios when the exposure of prime interests, relative to disease incidence, has more than two levels. An illustrative example is presented and discussed.
On a Martingale Approach for the Estimation of the Parameters of a Bivariate Carrier Borne Epidemic Model in Presence of a Linear Relationship Between Carriers and Suspectibles
Authors: Biswas S. , Thomas M. 
Published: May 2007

AbstractThe present investigation is to waive the restriction of PICARD (1980) viz. x0 + y0 = n (the size of the population) for the obvious reason that the size of the susceptible population exposed to risk will depend on the growth rate of carriers and to evolve a simple methodology for the estimation of parameters of Downton's bivariate model. A lienar relationship of Xt on Yt enabled to predict the size of the susceptible population exposed to the risk by a given number of carriers at any time. The same linear equation, when incorporated in Downton's bivariate model has generated the marginal process of Yt. Using several Martingales constructed on the basis of the above marginal process, the minimum number of carriers that can bring out an epidemic and various parameters of Downton's model have been estimated.
An Evaluation of Beta‐Binomial and Dirichlet‐Trinomial Models for the Analysis of Reproductive and Developmental Effects
Authors: Chen James J. , Li Lung‐An 
Published: May 2007

AbstractThe common endpoints for the evaluation of reproductive and developmental toxic effects are the number of dead/resorbed fetuses, the number of malformed fetuses, and the number of normal fetuses for each litter. The joint distribution of the three endpoints could be modelled by a Dirichlettrinomial distribution or by a product of two‐beta‐binomial distributions. A simulation experiment is used to investigate the biases of the maximum likelihood estimate (MLE) for the probability of adverse effects under the Dirichlet‐trinomial model and the beta‐binomial model. Also, the type I errors and powers of the likelihood ratio test for comparing the difference between treatment and control are evaluated for the two underlying models.In estimation, the two MLE's are comparable, the bias estimates are small. In testing, the likelihood ratio test is generally more powerful under the Dirichlet‐trinomial model than the beta‐binomial model. The type I error rate is greater than the nominal level using the Dirichlet‐trinomial model in some cases, when the data are generated from the two‐beta‐binomial model, and it is less than the nominal level using the beta‐binomial model in other cases, when the data are generated from the Dirichlet‐trinomial model.
An Extended Class of Ranking Models
Authors: Sharma A. , Wolfe D. A. 
Published: May 2007

AbstractA further enlargement of the class of generalized Mallow's ranking models considered by Fligner and Verducci is proposed. Included in this enlarged class are rank probability distributions other than the uniform that lead to symmetric distributions for many of the common measures used to assess distances between rankings. A particular application to the standard Kendall distance is illustrated in more detail.
Confidence Intervals on Ratios of Variance Components for the Unbalanced Two Factor Nested Model
Authors: Sen Bhabesh , Graybill Franklin A. , Ting Naitee 
Published: May 2007

AbstractThe model considered in this article is the two‐factor nested unbalanced variance component model:
equation image
for p = 1, 2, …, P; q = 1, 2, …, Qp; and r = 1, 2, …, Rpq. The random variables Ypqr are observable. The constant μ is an unknown parameter, and Ap, Bpq and Cpqr are (unobservable) normal and independently distributed random variables with zero means and finite variances σ2A, σ2B, and σ2C, respectively. Approximate confidence intervals on ϱA and ϱB using unweighted means are derived, where
equation image
The performance of these approximate confidence intervals are evaluated using computer simulation. The simulated results indicate that these proposed confidence intervals perform satisfactorily and can be used in applied problems.
An Empirical and Simulated Comparison of Some Tests for Detecting Progressiveness of Response with Increasing Doses of a Compound
Authors: Capizzi Thomas , Survill Tracy T. , Heyse Joseph F. , Malani Hina 
Published: May 2007

AbstractExperiments consisting of several doses of a test agent and a zero dose control are often conducted to evaluate the effect of a compound on the response of interest. TUKEY et al. (1985) proposed a trend test procedure which uses the minimum p‐value from three candidate dose scalings as a sensitive means for detecting a trend in response with increasing dose. Trend is defined here as a progressiveness, either increasing or decreasing, in response with increasing dose of the test agent. In this paper, we take a closer look at the procedure's inflated type I error rate and propose an adjustment based on the multivariate t‐distribution which preserves the nominal significance level. Application of the adjusted trend test to a number of real data sets indicates that its performance is similar to that observed with Bartholomew's and Williams' tests. An evaluation of these three tests also was conducted on simulated data using an apparently novel approach which takes into account the underlying dosage regimen to genrate the alternative hypotheses for a broad range of dose response relations. The simulation results indicates that the adjusted trend test is overall more powerful than its two competitors, although there are circumstances where each procedure appears superior. This broad‐based power exhibited in both real and simulated settings makes the adjusted trend test an attractive approach.