bluuebunny/crossref_metadata_2025 huggingface dataset:
Photochemistry of Cobalt(III) Complexes Containing a Sulfinate-S Ligand. Linkage and Geometrical Isomerization
Authors: Akhter Farooque MD , Hirotsu Masakazu , Sugimoto Isamu , Kojima Masaaki , Kashino Setsuo , Yoshikawa Yuzo
Published: June 2006

Photolysis of trans(t-N,S)-[Co{S(O)2CH2COO-S,O}(tren)]+ (1, t–N = tertiary amine nitrogen; tren = tris(2–aminoethyl)amine) with visible light yielded two complexes, orange and red. The molecular structure of the orange complex perchlorate was determined by the X-ray method to be cis(t-N,O(S))-[Co{OS(O)CH2COO-O,O}(tren)]ClO4·H2O (2, O(S) = oxygen of sulfinate group); geometrical isomerization as well as linkage isomerization took place upon photolysis. A mechanism for the geometrical isomerization was proposed. The red complex, which was assigned as trans(t-N,O(S))-[Co{OS(O)CH2COO-O,O}(tren)]+ (3), is thermally unstable and reverts to the starting complex. This observation is in accord with molecular mechanics calculations, which estimate the starting complex to be more stable. The kinetic studies were performed using the HPLC method in the temperature range 28—70 °C, giving ΔH‡ = 100 kJ mol−1 and ΔS‡ = −23 J K−1 mol−1. Photolysis of a cobalt(III) complex containing the l-cysteinesulfinate-S,N ligand, cis(t-N,S)-lsqb;Co{S(O)2CH2CH(COOH)NH2-S,N}(tren)]2+ (4) with visible light provided two types of linkage isomers, cis(t-N,O(C))-[Co{NH2CH(CH2SO2−)COO-N,O}(tren)]+ (4b, O(C) = oxygen of carboxylate group) with an uncoordinated sulfinate group, and a pair of diastereomers of cis(t-N,O(S))-[Co{OS(O)CH2CH(COOH)NH2-O,N}(tren)]2+ (4a). The molecular structures of the perchlorate of 4b and the bromide of 4a with the (S)-sulfur atom have been determined by X-ray diffraction. Isomerization (epimerization) from 4a-R to 4a-S was studied in the temperature range 55—75 °C, giving ΔH‡ = 105 kJ mol−1 and ΔS‡ = −20 J K−1 mol−1. Photolysis of trans(t-N,S)-[Co{S(O)2CH2CH(COOH)NH2-S,N}(tren)]2+ (5) yielded six products. Three of them were the same as those obtained by the photolysis of 4, indicating that geometrical isomerization took place.
Coordination Chemistry of Some Low Coordinate Organophosphorus Compounds of Coordination Number 2
Authors: Yoshifuji Masaaki
Published: June 2006

The structures of transition metal complexes with low coordinate organophosphorus compounds are described; these compounds involve diphosphenes, phosphaethenes, phosphaallenes, phosphabutatrienes, and so on of coordination number 2. They are discussed in terms of X-ray crystallographic analysis and 31P NMR analysis.
Fluorescence Emission and Cycloaddition Reaction Induced by Ionizing Radiation in 2,5-Distyrylpyrazine Molecular Crystal : A Comparison to the Photo-Illuminated Systems
Authors: Ishida Wataru , Takenaka Yasuyuki , Miyatake Yoko , Hase Hirotomo , Ogasawara Masaaki
Published: June 2006

Fluorescence emission and cycloaddition reaction induced in 2,5-distyrylpyrazine crystal by ionizing radiation were studied by means of pulse radiolysis and 60Co γ-ray radiolysis. Lifetimes of the fluorescence in the photo-illuminated crystal were also studied for comparison by using pico-second laser photolysis techniques. The fluorescence spectrum obtained by pulse radiolysis was similar to that obtained by laser-photolysis, which led us to conclude that excimers were formed by electron beam-irradiation as well. The occurrence of [2+2] cycloaddition reaction of DSP by γ-irradiation was monitored by observing the concentration change of the olefinic double bond. The high G-value, 4—5, for the decrease of the olefinic double bond suggested efficient activation of DSP in the irradiated crystal.
Electronic Structures of the Hückel Ring and the Möbius Ring
Authors: Ohmae Takayuki , Aono Shigeyuki
Published: June 2006

The electronic structures of the Hückel- and Möbius type species are investigated in the Hückel approximation. The Green’s function approach is employed to evaluate the total energy, the charge density and the bond order of various series. The results are successfully expressed in analytical forms, which displays the Hückel 4m + 2 and the Möbius 4m rules very clearly.
Rotator Phase in Dodecylammonium Chloride Studied by 1H and 2H Solid NMR and Thermal Measurements
Authors: Tanaka Susumu , Onoda-Yamamuro Noriko , Ishimaru Shin’ichi , Ikeda Ryuichi
Published: June 2006

1H NMR spin-lattice relaxation times, T1 and T1ρ, the second moment M2 of 1H NMR linewidth, 2H NMR spectra, powder X-ray diffraction, electrical conductivity, and thermal measurements have been performed on C12H25NH3Cl and C12H25ND3Cl in the range between room temperature and the melting point. From these measurements, the presence of the rotator phase was revealed above ca. 345 K, where a highly disordered structure characterized by the rapid 2-D self-diffusion as well as the axial rotation of the cations taking place in the lamellar-type double layer structure is formed. These molecular motions, the crystal structure and the thermal nature found in this phase indicate that the rotator phase is close to the plastic crystal and can be described as “a low-dimensional plastic phase”. The determined dynamic parameters of molecular motions in this phase were compared with those in the values reported in the rotator phases of short alkyl chain analogues.
A Study on the Adsorption Characteristics of Acetone and Benzene in Supercritical Carbon Dioxide Measured by Chromatography and IR Spectroscopy
Authors: Jin Do Won , Nitta Tomoshige , Park Dong-Won
Published: June 2006

Chromatographic and FTIR techniques were applied to a study of the absorption characteristics of acetone and benzene on a silica gel (SG800) in supercritical CO2 at 313.2 and 333.2 K. The chromatographic isotherms for acetone and benzene have a maximum at a pressure lower than the critical pressure of CO2, and then decrease with increasing pressure. When the temperature increases, the adsorption isotherms decrease in the low-pressure region, and increase in the high-pressure region, providing a crossover at a relatively high pressure. The elution curves of acetone showed tailing, even at high pressures, while those of benzene showed quasi-Gaussian curves at high pressures. The tailing curves for acetone indicate the existence of heterogeneous sites; evidence of hydrogen-bonding formation with surface silanol groups has been provided by IR spectroscopy.
Intercalation of Anticancer Agent Cytarabine and Its Related Compounds into
γ
-Titanium Phosphate
Authors: Danjo Mayumi , Mizuguchi Yukari , Yagita Yukari , Kakiguchi Kazuyo , Yanagida Tomomi , Tsuhako Mitsutomo
Published: June 2006

The intercalation of nucleic acid-related compounds which have the pyrimidine structure into the layered titanium phosphate, Ti(H2PO4)(PO4)·2H2O (γ-TiP), was examined. The intercalation of cytosine derivatives such as anticancer agent cytarabine was successful. In addition, cytarabine release tests from the obtained cytarabine intercalation compound of γ-TiP were performed in various kinds of solutions containing sodium ions. The release of cytarabine became slower by intercalation into the layered phosphate. Cytarabine release was strongly influenced by the pH value and the concentration of sodium ions in the test solution. In the reaction in aqueous solutions with higher concentrations of sodium ion and/or higher pH values, the ion-exchange of Na+ and protonated cytarabine in the intercalation compound and the disintegration of the layered structure of γ-TiP occurred. On the other hand, in the solutions with the lower sodium ion concentration and the lower pH value, the layered structure of γ-TiP was disintegrated and cytarabine in the interlayer region rearranged.
The Reaction of Polyhalides with Allylsilanes Catalyzed by Copper(I) Chloride
Authors: Mitani Michiharu , Hujita Shigenori
Published: June 2006

Allyltrimethylsilane reacted with polyhalogen compounds in the presence of copper species, such as copper(I) chloride, copper(II) chloride or metallic copper, to form polyhalo compounds containing an allyl group. Other allylsilane derivatives than allyltrimethylsilane were also subjected to a reaction with carbon tetrachloride. 3-Chloro- or 3-bromo-3-trimethylsilyl-1-propene gave 4,4,4-trichloro-1-trimethylsilyl-1-butene. Ethyl 1-trimethylsilylallyl carbonate afforded ethyl 4,4,4-trichloro-1-butenyl carbonate along with a hydrotrichloromethylation product. 2-Methyl-3-trimethylsilyl-1-propene yielded a product based on the addition of a trichloromethyl group followed by hydrogen-elimination from a 2-methyl group.
Direct Oxidation of Methyl Ethers to Carbonyl Compounds with a Combination of Nitrogen Dioxide and Water in the Presence or Absence of Ozone
Authors: Suzuki Hitomi , Takeuchi Toyomi , Mori Tadashi
Published: June 2006

A combination of nitrogen dioxide and water has been found to provide a new agent for the transformation of various alkyl methyl ethers 1 (R = Me) to carbonyl compounds 2 under mild conditions. The oxidation can be achieved successfully in dichloromethane, but hexafluoro-2-propanol was found to be most satisfactory as the solvent. The reaction was generally clean, and simple evaporation gave the expected oxidation product 2 in moderate to good yield. In the presence of ozone, but without water, the similar oxidation was observed only after prolonged reaction time, suggesting that some initial minor reaction with a strong oxidant, possible nitrogen trioxide, afforded an acidic promoter, which then worked as a catalyst similar to that involved in the reaction with a nitrogen dioxide and water system.
Hemophagocytic Lymphohistiocytosis Complicating Influenza A Infection
Authors: Mou Steven S. , Nakagawa Thomas A. , Riemer Ellen C. , McLean Thomas W. , Hines Michael H. , Shetty Avinash K.
Published: June 2006

During the influenza A (H3N2) season of 2003–2004, several influenza-related complications and deaths were reported in children. Hemophagocytic lymphohistiocytosis complicating influenza A infection is very rare. We report a 3-year-old girl who presented with severe pneumonia and hemophagocytic lymphohistiocytosis associated with influenza A infection. Clinicians should be aware of hemophagocytic syndrome as a serious complication of influenza A infection.
Compression/tension load capacity of stone column anchors
Authors: Liu K.-F. , Xie X.-Y. , Zhang J.-F. , Zhu X.-R.
Published: June 2006

Stone column anchors are a newly developed innovative method of resisting vertical tension and compressive loads on very soft ground such as reclaimed land. In the stone column anchor system, the ground slab is connected to an anchored frustum at the base of the column by a steel bar. This enables the stone column anchor to resist tension loads, while the shaft of the stone column and the surrounding soil form a composite foundation to resist compressive loads. This paper examines the vertical compression/tension load-carrying capacity of single stone column anchors tested under repeated loading. The results show that stone column anchors can be used to provide an increased tension and compression ground load-carrying capacity. The system has been implemented on reclaimed land for the construction of a new sewage treatment plant.
Design of braced excavations to limit ground movements
Authors: Osman A. S. , Bolton M. D.
Published: June 2006

The authors have developed a new approach to the estimation of ground movements around braced excavations retaining thick deposits of soft clay, incorporating actual stress–strain data and the undrained shear strength profile of the soil on site. The method is based on the assumption of a plastic deformation mechanism local to a braced excavation, and which avoids any slippage on shear surfaces. Mobilised shear stresses beneath and around the face are found from an equilibrium calculation derived from the deformation mechanism by virtual work. The strains required to mobilise these stresses are finally entered into the deformation mechanism to predict boundary displacements. The outcome is a prediction based on simple calculations that otherwise would have called for elaborate constitutive modelling and finite element analysis. The capability of this mobilisable strength design (MSD) method in calculating the magnitude of wall displacements is demonstrated through the back-analysis of a previously published case history of a braced excavation at a soft clay site in Singapore. The relative effectiveness of heave-reducing piles in controlling ground movements is then demonstrated using the MSD method.
Rock-socketed pile design and construction: a better way?
Authors: Haberfield C. , Collingwood B.
Published: June 2006

Piles socketed into rock are often used to support heavy loads from buildings and infrastructure. Piles typically of up to 1·8 m diameter carrying safe working loads of up to 40 MN are utilised in Australia. Their design has traditionally been based on conservative, empirical rules. GARSP (Golder Associates Rocket field Socket Procedure) is a recent design innovation that provides a serviceability approach to design, and allows socket lengths to be optimised during the drilling process, often resulting in significant savings. It also provides better control of the risks associated with unexpected ground conditions and with construction of the pile. GARSP has been used in collaboration with Wagstaff Piling on several large-scale socketed pile projects in Melbourne, Australia, including the second hotel for Crown Casino, the new grandstand at the Melbourne Cricket Ground, the redevelopment of Spencer Street Station, and several residential towers. The adoption of this approach for these projects in conjunction with best practice construction techniques has resulted in significant cost savings in terms both of materials and of construction time. This paper briefly describes the traditional design approaches and the basic components of GARSP, and then presents some recent projects where it has been used.
Building a deep isolating wall by an existing rail tunnel
Authors: Molins C. , Ledesma A.
Published: June 2006

This paper describes the design, construction and early performance of a retaining structure close to a subway tunnel in Barcelona. The excavation, about 16 m deep, was carried out in 2001 during the construction of a new hospital, and involved a rectangular area with the longer side (170 m) almost parallel to the tunnel. The design had to fulfil two requirements: first, the influence of the excavation on the existing tunnel had to be minimised; and, second, the new hospital had to be isolated from vibrations from the subway owing to the high sensitivity of the medical instruments. In order to achieve this, the retaining wall was designed to be independent of the main building, and movements during the excavation stages had to be controlled. In addition, the use of subhorizontal anchors was not allowed by the metro administration, and therefore the wall comprised a line of T-shaped panels linked to shorter intermediate panels excavated using a hydromill. The stability of the wall and bending resistance were provided by the buttressing effect of the forward-facing T and the compression in the panels and anchoring force provided by post-tensioning anchors drilled into the underlying bedrock through ducts installed in the rear section of the T panels. The wall was designed using a beam–spring model with ground parameters derived from in situ tests, and the interaction between the excavation and the tunnel was modelled using a plane-strain finite element analysis imposing the wall displacements on the section. Monitoring of the wall and the tunnel confirmed that the influence of the work on the neighbouring tunnel was negligible.
Factors That Determine the Non-Linear Amygdala Influence on Hippocampus-Dependent Memory
Authors: Akirav Irit , Richter-Levin Gal
Published: June 2006

Stressful experiences are known to either improve or impair hippocampal-dependent memory tasks and synaptic plasticity. These positive and negative effects of stress on the hippocampus have been largely documented, however little is known about the mechanism involved in the twofold influence of stress on hippocampal functioning and about what factors define an enhancing or inhibitory outcome. We have recently demonstrated that activation of the basolateral amygdala can produce a biphasic effect, enhancement or inhibition, of hippocampal synaptic plasticity, depending on the timing of activation (priming or spaced activation). A key question is under which conditions do the effects of amygdala activation on hippocampus dependent memory functions change from improvement to impairment of learning and memory. In this chapter we suggest that hippocampal outcome of amygdala activation may be critically dependent on four main factors: (1) The intensity of amygdala activation, (2) the temporal relation between the activation of the amygdala and the hippocampus dependent memory function, (3) the duration of amygdala activation, and (4) the contextual input during the processing of the information.
Concentration Dependent Actions of Glucocorticoids on Neuronal Viability and Survival
Authors: Ábrahám István M , Meerlo Peter , Luiten Paul GM
Published: June 2006

A growing body of evidence based on experimental data demonstrates that glucocorticoids (GCs) can play a potent role in the survival and death of neurons. However, these observations reflect paradoxical features of GCs, since these adrenal stress hormones are heavily involved in both neurodegenerative and neuroprotective processes. The actual level of GCs appears to have an essential impact in this bimodal action. In the present short review we aim to show the importance of concentration dependent action of GCs on neuronal cell viability and cell survival in the brain. Additionally, we will summarize the possible GC-induced cellular mechanisms at different GC concentrations providing a background for their effect on the fate of nerve cells in conditions that are a challenge to their survival.
Some aspects of modern population mathematics
Authors: Brillinger David R.
Published: June 2006

The purpose of this paper is to survey a number of the technical tools and models that have found use in the study of human and other populations, and to indicate some problems of current interest. These tools and models are varied: integral equations, nonlinear oscillations, differential geometry, dynamical systems, nonlinear operations, bifurcation theory, semigroup theory, martingale theory, Markov processes, diffusion processes, branching processes, ergodic theory, prediction theory and state‐space models. A fairly extensive bibliography is provided. Also an Appendix has been added describing the analysis of a classical entomological data set.
Dropping observations without affecting posterior and predictive distributions
Authors: Draper Norman R. , Guttman Irwin
Published: June 2006

Suppose in a distribution problem, the sample informationWis split into two piecesW1andW2, and the parameters involved are split into two sets, π containing the parameters of interest, and θ containing nuisance parameters. It is shown that, under certain conditions, the posterior distribution of π does not depend on the dataW2, which can thus be ignored. This also has consequences for the predictive distribution of future (or missing) observations. In fact, under similar conditions, the predictive distributions usingWor justW1are identical.
Statistics, images, and pattern recognition
Authors: Ripley Brian D.
Published: June 2006

Data are increasingly being collected in the form of images, especially in fields using remote sensing and microscopy. Statisticians are becoming interested in developing techniques to handle the highly structured data of images. Statistical work in this area is surveyed, and two problems discussed in more detail. The first is a form of image segmentation, classifying the pixels of a satellite picture by land use. The second is the summarization of electron micrographs.
Refining binomial confidence intervals
Authors: Casella George
Published: June 2006

A method for refining an equivariant binomial confidence procedure is presented which, when applied to an existing procedure, produces a new set of equivariant intervals that are uniformly superior. The family of procedures generated from this method constitute a complete class within the class of all equivariant procedures. In certain cases it is shown that this class is also minimal complete. Also, an optimally property, monotone minimaxity, is investigated, and monotone minimax procedures are constructed.
Relations between statistics for testing exponentiality and uniformity
Authors: Currie Iain D. , Stephens Michael A.
Published: June 2006

It is shown that Greenwood's statistic for uniformity and the Hahn‐Shapiro and Stephens statistics for exponentiality with known origin are equivalent. It is also shown that the distribution of the Shapiro‐Wilk statistic for testing the hypothesis of exponentiality with unknown origin is obtainable from the distribution of Greenwood's statistic.
On the asymptotic distribution of a class of aligned rank order test statistics in randomized block designs
Authors: Tardif Serge
Published: June 2006

In the present investigation, the unconditional asymptotic distribution of a class of aligned rank order test statistics for randomized block designs is derived under the null hypothesis and for nearby alternatives, as the number of blocks tends to infinity. The proofs of these results are based on the asymptotic equivalence in quadratic mean between aligned observations and their ranks and thus are quite similar to the Hájek and SKidák (1967) approach.
On aliasing and generalized defining relationships of factorial arrangements
Authors: Raktoe B. L. , Pesotan H. , Federer W. T.
Published: June 2006

The concepts of defining contrast (DC), generalized defining relationship (GDR) and aliasing structure (AS) are now well established in the terminology of regression analysis and factorial design theory. There is no complete agreement in the literature about the meaning of regular and irregular fractional factorial designs. This paper provides a workable definition of a regular fraction from a symmetrial prime‐powered factorial. It characterizes the uniqueness of the GDR for fractions from the most general factorial. Results are also présentés on the uniqueness of the GDR for regular designs, on orthogonality aspects of regular and irregular designs, and on group‐theoretic generation of the complete aliasing structure. Examples are provided to illustrate the developments.
Maximum likelihood estimation for mixtures
Authors: Hill David L. , Saunders Roy , Laud Purushottam W.
Published: June 2006

This paper studies maximum likelihood estimation of mixing probabilities ρk, k ≥ l, when the data have a density of the form g = Σpkfkfor known densitiesfk. An application to the shock model of Esary, Marshall and Proschan (1973) is considered in some detail. A simulation study which compares the maximum likelihood estimator to other available estimators for the case of finite mixtures is summarized.
Loss functions and admissibility of normal variance estimators
Authors: Wild C. J.
Published: June 2006

Loss functions and admissible estimators of the variance are considered with reference to a continuous family of loss functions in which both squared error in σ2 and squared error in the logarithm of σ2 are embedded. The optimality of estimates with respect to expected loss is found to be very loss‐function dependent and the cost of misspecifying the loss function is found to be high.
Minima and maxima in multivariate analysis
Authors: Wong Chi Song , Wong Kai Sang
Published: June 2006

A First derivative test for absolute maxima with monotone operators is used to find the maximum likelihood estimators of the parameters of certain multivariate models. Some informal arguments that overlook the lack of differentiability or which use symbolic derivatives are thereby tightened.
Small sample estimation of regression parameters in the three‐variable linear model, with incomplete observations
Authors: Dagenais Marcel G.
Published: June 2006

This paper describes a new method for estimating the parameters, in linear regression models containing one dependent and two independent variables, when some observations are incomplete. The proposed technique is a markedly improved version of an approach described in previous papers [2, 3]. Results of Monte Carlo experiments suggest that the adopted modifications enhance considerably the small sample performance of the estimators.
On the existence and non‐existence of quintic designs
Authors: Duthie Audrey I.
Published: June 2006

Quintic designs, a class of PBIB designs having five associate classes, are defined. Properties of NN', where N is the incidence matrix, are examined to present necessary conditions for the existence of quintic designs. The variances of elementary treatment comparisons are found. The block structure of two types of quintic design is studied.
Estimation in a simple linear model using prior beliefs
Authors: Singh Jagbir
Published: June 2006

This paper considers a two stage estimation for parameters in a simple linear model using prior beliefs. The proposed estimator is compared not only with the usual least square estimator but also is contrasted with the one proposed in [1]. The effect of prior beliefs being wrong is investigated.
The variability of rainfall acidity
Authors: Eynon Barrett P. , Switzer Paul
Published: June 2006

Two years of rainfall acidity data for the eastern United States were analyzed. The data consist of rainfall‐event pH measurements from a nine station monitoring network. A spatio‐temporal stochastic model, including deterministic components for seasonal variation and rainfall washout, and stochastic components for spatial, temporal, and measurement variation, was fitted to the data. The fitted autocorrelation structure from this model was used, in the process known as Kriging, to obtain BLUE contour maps of seasonal and rainfall adjusted yearly average pH over the monitoring region.
Dose‐response models for time‐to‐response toxicity data
Authors: Kalbfleisch John D. , Krewski Daniel R. , Van Ryzin Ohn
Published: June 2006

This paper concerns the modelling and analysis of toxicity data in which the time to some toxic response is recorded and of importance. The paper begins with a review of a variety of dose‐response models, including log‐linear, proportional hazards, multievent, and compartmental models, that have been suggested and used in this context. Models for competing risks are also reviewed and several possible approaches are considered and discussed in the context of dose response experiments. The formulation of a model for competing risks that utilizes cause‐specific hazards gives a natural basis for the modelling and analysis of certain experimental situations in which only partial information is available on the time to response. Such situations arise, for example, when the presence of tumour is not clinically detectable in carcinogenicity trials. Likelihood construction is discussed, and appropriate likelihood contributions are derived. The paper concludes with a discussion of measures of risk which take account of the time dependence of the toxic response under study.
Section associate editors' comments
Authors: Gentleman Jane F.
Published: June 2006

Au mois de novembre 1979, le déraillement d'un train passant par Mississauga, en Ontario, provoqua l'explosion de plusieurs wagons‐citernes contenant du propane liquide en plus de causer une fuite de chlore dans un autre wagon‐citerne. Des officiels évacuérent plus de 200,000 personnes hors de la région affectée; seuls les pompiers demeurérent à l'endroit de la tragédie, s'exposant dangereusement aux fumées toxiques provoquées par les explosions et les incendies. Suite aux événements, des représentants du Ministére de la Santé administrérent des examens médicaux et des questionnaires aux hommes ayant été exposés de même qu'à un groupe‐témoin composé de pompiers non exposés. Dautres données furent recueillies annuellement au cours des deux années qui suivirent le drame. Au cours de cette étude, deux groupes indépendants d'analystes examinérent les données afin de déterminer si les inhalations de produits chimiques à l'endroit du déraillement avaient des effets à long terme sur la fonction pulmonaire des pompiers de Mississauga.
A review of optimal designs in survey sampling
Authors: Bellhouse David R.
Published: June 2006

Results in five areas of survey sampling dealing with the choice of the sampling design are reviewed. In Section 2, the results and discussions surrounding the purposive selection methods suggested by linear regression superpopulation models are reviewed. In Section 3, similar models to those in the previous section are considered; however, random sampling designs are considered and attention is focused on the optimal choice of πj. Then in Section 4, systematic sampling methods obtained under autocorrelated superpopulation models are reviewed. The next section examines minimax sampling designs. The work in the final section is based solely on the randomization. In Section 6 methods of sample selection which yield inclusion probabilities πj=n/Nand πij=n(n‐ 1)/N(N‐ 1), but for which there are fewer thanNCnpossible samples, are mentioned briefly.
On estimating the difference of location parameters of two negative exponential distributions
Authors: Mukhopadhyay Nitis , Hamdy Hosny I.
Published: June 2006

Fixed‐width confidence intervals for the difference of location parameters of two negative‐exponential distributions have been constructed through two‐stage and purely sequential schemes. The two cases when the scale parameters are equal but unknown, and unequal but unknown, have been dealt with separately. Our two‐stage procedures guarantee the exact confidence coefficient to be at least the nominal prescribed level. Various second‐order expansions are also considered when sequential procedures are proposed. It is noted that no new tables are needed to implement these procedures in practice.
Further remarks on asymptotic normality of likelihood and conditional analyses
Authors: Fraser D. A. S. , Mcdunnough P.
Published: June 2006

Under weak conditions the normalized likelihood with or without weight function almost surely converges to a normal density function: for a real parameter or a vector parameter; with or without the assumption of independent identical distributions. Applications arise for confidence intervals, confidence distributions, structural distributions. and conditional analyses with transformation and structural models.
Some observations on semi‐markov models for partially censored data
Authors: Matthews David E.
Published: June 2006

Cause‐specific hazard functions are employed to analyze a semi‐Markov model which could be used to describe data arising from clinical trials or certain types of observational studies. The use of these hazard functions to fit a set of data arising from N possibly incomplete case histories is shown to have several notable advantages over the approach adopted by Lagakos, Sommer, and Zelen (1978).
Un cas élémentaire d'oscillations
Authors: Kohler Boris A.B.
Published: June 2006

The probability laws describing the numbers of oscillations of the continuous symmetric random walk express themselves through the numbers of Stirling of first kind. The asymptotic behavior can easily be derived using characteristic functions.
Asymptotic normality of the lengths of a class of nonparametric confidence intervals for a regression parameter
Authors: Puri Madan L. , Wu Tiee‐Jian
Published: June 2006

In the linear regression model, the asymptotic distributions of certain functions of confidence bounds of a class of confidence intervals for the regression parameter arc investigated. The class of confidence intervals we consider in this paper are based on the usual linear rank statistics (signed as well as unsigned). Under suitable assumptions, if the confidence intervals are based on the signed linear rank statistics, it is established that the lengths, properly normalized, of the confidence intervals converge in law to the standard normal distributions; if the confidence intervals arc based on the unsigned linear rank statistics, it is then proved that a linear function of the confidence bounds converges in law to a normal distribution.
Teaching Statistics in Canada: The Early Days
Authors: Watts Donald G.
Published: June 2006

A brief history of the development of statistics in Canadian Universities is presented.
Certain nonparametric classification rules and their asymptotic efficiencies
Authors: Govindarajulu Z. , Gupta A. K.
Published: June 2006

Two nonparametric classification rules for e‐univariace populations are proposed, one in which the probability of correct classification is a specified number and the other in which one has to evaluate the probability of correct classification. In each case the classification is with respect to the Chernoff and Savage (1958) class of statistics, with possible specialization to populations having different location shifts and different changes of scale. An optimum property, namely the consistency of the classification procedure, is established for the second rule, when the distributions are either fixed or “near” in the Pitman sense and are tending to a common distribution at a specified rate. A measure of asymptotic efficiency is defined for the second rule and its asymptotic efficiency based on the Chernoff‐Savage class of statistics relative to the parametric competitors ie the case of location shifts and scale changes is shown to be equal to the analogous Pitman efficiency.
Optimum spacings of elementary treatment contrasts in symmetrical 2‐factor pa block designs
Authors: Sia L. L.
Published: June 2006

The concept of optimum spacing of an arbitrary group of treatments was introduced by Sinha and Sinha (1969) in a study of the relative efficiencies of a group of block designs. In this paper, the optimum spacings of elementary treatment contrasts in a 2‐factor symmetrical block design with Property A are studied using the A‐optimality criterion. Conditions for optimum spacings are expressed in terms of the relative magnitudes of the efficiency factors.
The strong uniform convergence of multivariate variable kernel estimates
Authors: And Luc Devroye , Penrod Clark S.
Published: June 2006

We show that sup, completely as, where f is a uniformly continuous density on are independent random vectors with common density f, and fn is the variable kernel estimate

Here Hni is the distance between Xi and its kth nearest neighbour, K is a given density satisfying some regularity conditions, and k is a sequence of integers with the property that log asn
A concise proof of a theorem on products of power sums
Authors: Dwyer P. S. , Mikhail N. N. , Tracy D. S.
Published: June 2006

The heart of a direct solution of the problem of moments of moments is a formula for the expected value of a product of sample power sums in terms of a linear function of products of population power sums. Such a result was given by Skellam (1949) and, earlier and more generally, by Dwyer (1938). The approach here leads to a result for the easily handled case which features the product of unit power sums of each multivariate variable from which a general case comes by easy extension without the need of technical material required by the earlier approaches. A corollary provides a new solution for the problem of obtaining the unbiased estimate of any linear function of products of power sums.
Another characterization of the weibull distribution
Authors: Janardan K. G. , Schaeffer D. J.
Published: June 2006

A necessary and sufficient condition is given that an absolutely continuous positive random variable follow a Weibull distribution. The condition Is based on some functions of order statistics.
Ballot theorem and lattice path crossings
Authors: Kern Malcolm , Walter Stanley
Published: June 2006

We consider lattice paths which cross the diagonal exactly r times, and by a simple method determine the number of such paths when the endpoint is given. Then as a byproduct we easily obtain Feller's (1968, p.84) result for crossings when the length is given.
Interval estimates for variance components
Authors: Venables W. , James A. T.
Published: June 2006

A new approach to inference on variance components is propounded. This approach not only gives a new justification for Fisher's fiducial, distribution for the “between classes” component, but also leads to a new distribution for the “within classes” component. This latter distribution is studied, and has some intuitively very reasonable properties. Numerical results are given.
A mixed poisson–inverse‐gaussian regression model
Authors: Dean C. , Lawless J. F. , Willmot G. E.
Published: June 2006

The mixed Poisson–inverse‐Gaussian distribution has been used by Holla, Sankaran, Sichel, and others in univariate problems involving counts. We propose a Poisson–inverse‐Gaussian regression model which can be used for regression analysis of counts. The model provides an attractive framework for incorporating random effects in Poisson regression models and in handling extra‐Poisson variation. Maximum‐likelihood and quasilikelihood‐moment estimation is investigated and illustrated with an example involving motor‐insurance claims.
Second‐order inference for generalized least squares
Authors: Fraser D. A. S. , Massam H.
Published: June 2006

Confidence regions for generalized least squares are commonly derived from a measure of departure calculated on the tangent plane at the MLE or on the tangent plane at the true value; the first gives approximate confidence regions, the second exact. For surfaces with curvature, indeed with varying curvature, the exact regions typically are not likelihood regions and can include parameter values of highest and of lowest likelihood. This paper develops an alternative approach to deriving exact confidence regions and uses both surface curvature and distance from the surface as supporting ingredients. For this, conditionality is invoked in two ways beyond that supported by the usual conditionality principle. For the case of normal error the ordinary chi‐squared departure is replaced by a Von Mises‐type angular (or cosine) departure which is assessed using curvature properties in the data direction and radial distance of the data from the regression surface. For the usual linear model (constant curvature equal to zero) the method coincides with the ordinary tests and confidence regions; for the case of constant nonzero curvature, the method generalizes to spheres and sphere‐cylinders the Fisher (Statistical Methods and Scientific Inference, 1956) analysis of a rotationally symmetric normal on ℝ2with mean constrained to a circle. The effects of conditioning are indicated by a computer plot for obtaining 95% confidence.
Asymptotic properties of Bayes risk for one‐sided tests
Authors: Johnson Bruce R. , Truax Donald R.
Published: June 2006

Consider a given sequence {Tn} of estimators for a real‐valued parameter θ. This paper studies asymptotic properties of restricted Bayes tests of the following form: reject H0:θ ≤ θ0 in favour of the alternative θ > θ0 if Tn ≤ Cn, where the critical point Cn is determined to minimize among all tests of this form the expected probability of error with respect to the prior distribution. Such tests may or may not be fully Bayes tests, and so are called Tn‐Bayes. Under fairly broad conditions it is shown that

and the Tn‐Bayes risk

where an is the order of the standard error of Tn, ‐ is the prior density, and μ is the median of F, the limit distribution of (Tn – θ)/anb(θ). Several examples are given.
Equi‐information robust designs: Which designs are possible?
Authors: Herzberg Agnes M. , Prescott P. , Akhtar M.
Published: June 2006

The effects of missing observations in a designed experiment are reviewed. Conditions are determined for a design to retain equal information, i.e. the same generalized variance of unknown parameters, when either any single or any pair of observations is lost. Some examples of designs with this property are given. Although there are many designs which retain equal information for the loss of exactlytobservations, wheret= 1,2,3,…, it is shown that it is not possible to obtain any design which retains equal information when any one and any two and also any three observations are missing.
Transient analysis of birth‐death processes with two boundaries
Authors: Campbell L. Lome
Published: June 2006

This paper considers a birth‐death process with constant birth rate, constant death rate, and a finite set of states {0,1, …, m – 1}. If the process is in state 0 and a death occurs, it goes instantaneously to state k with a given probability, and if it is in state m – 1 and a birth occurs, it goes to state k with another given probability. The Laplace transform of the generating function for the probabilities is obtained. The steady‐state probabilities and a polynomial equation for the poles of the transform are then obtained. The particular example where the process moves a units into the interior whenever it reaches a boundary is examined. This example includes, for a = 0, the well‐known M/M/1 queue with a finite waiting room.

Considérons un processus de naissance et de mort possédant un ensemble fini ďétats {0,1, …, m – 1} et dont les taux de naissance et de mort sont tenus constants. Lorsque le processus est dans l'état 0 et qu'un décès survient, on convient de renvoyer le processus à l'état k avec une certaine probabilité fixée a l'avance; de měme, le processus revient à l'état k si une naissance survient au moment il se trouve dans l'état m – 1. Sous de telles hypothèses, nous calculons la transformée de Laplace de la fonction génératrice des probabilités de transition. Les pǒles de cette transformée doivent satisfaire une équation polynomiale que nous déduisons. Nous déduisons aussi les probabilités stationnaires du processus. Nous examinons de façon particulière le cas où le processus se déplace de a unités vers l'intérieur à chaque fois qu'il atteint l'une des extrémités de son domaine. Lorsque a = 0, cet exemple se réduit au cas classique ďun phénomène ďattente de type M/M/1 avec salle ďattente à capacite finie.
Uniform asymptotic linearity in a regression parameter of a process based on a rank statistic
Authors: Boulanger Alain
Published: June 2006

For X1, …, XNa random sample from a distribution F, let the process SδN(t) be defined as

where K2N= σNi=1(ci− c̄)2

and R xi, + Δd, is the rank of Xi+ Δdi, among X1+ Δd1, …, XN+ ΔdN. The purpose of this note is to prove that, under certain regularity conditions onFand on the constantscianddi, SΔN(t) is asymptotically approximately a linear function of Δ, uniformly intand in Δ, |Δ| ≤C. The special case of two samples is considered.
A characterization of invariant power‐series abundance distributions
Authors: Wani Jagannath K. , Lo Hing Po
Published: June 2006

Consider a population the individuals in which can be classified into groups. Let y, the number of individuals in a group, be distributed according to a probability function f(y;øo) where the functional form f is known. The random variable y cannot be observed directly, and hence a random sample of groups cannot be obtained. Consider a random sample of N individuals from the population. Suppose the N individuals are distributed into S groups with x1, x2, …, xS representatives respectively. The random variable x, the number of individuals in a group in the sample, will be a fraction of its population counterpart y, and the distributions of x and y need not have the same functional form. If the two random variables x and y have the same functional form for their distributions, then the particular common distribution is called an invariant abundance distribution. The paper provides a characterization of invariant abundance distributions in the class of power‐series distributions.
Minimum‐distance methods based on quadratic distances for transforms
Authors: Luong A. , Thompson M. E.
Published: June 2006

A class of minimum‐distance methods based on empirical transforms is considered. This class includes the minimum‐chi‐squared method, the K‐L method for empirical characteristic functions, and the analogous method for empirical moment generating functions. Asymptotic properties of the minimum‐distance estimators and goodness‐of‐fit test statistics are derived. A general analogue of the Rao‐Robson statistic is formulated.
Invariance principles in probability for stable processes generated by a class of dependent sequences
Authors: Dabrowski André Robert
Published: June 2006

We prove an invariance principle in probability for φ‐mixing sequences of random variables taking values in a separable Banach space. The conditions on the dependence structure required for this approximation result are known to be necessary and sufficient for weak convergence of the partial‐sum process to the appropriate limiting process.
A comparison of regression models for ordinal data in an analysis of transplanted‐kidney function
Authors: Greenwood C. , Farewell V.
Published: June 2006

Three regression models for ordinal data, those of Fienberg, McCullagh, and Anderson, are applied to an analysis of kidney function among transplant recipients. The conclusions arising from each model are presented and contrasted.
An inequality for random replacement sampling plans
Authors: O'Brien George L. , Wong Augustine
Published: June 2006

A sample (X1 …, Xn) is drawn from a population of size N. Karlin (1974) conjectured that for any function ϕ in a certain class of real‐valued functions on the sample space, ϕ is at least as large for sampling with replacement as for any other random replacement sampling plan. This conjecture is proved under the assumption that ≫
Temporal patterns in twenty years of canadian homicides
Authors: Gentleman Jane F. , Whitmore G. A.
Published: June 2006

Detailed data describing all homicides in Canada known to the police are collected by Statistics Canada. In this study, three independent teams of analysts search for seasonality and other temporal patterns in homicide rates and frequencies between 1961 and 1980.
On distinguishability of sets of distribution functions and non‐parametric median problem
Authors: Basu A.K.
Published: June 2006

Hoeffding and Wolfowitz's concept of “distinguishability of sets of distributions” has been extended to two‐sample problems. We have shown that the two‐sample problem about equality of two medians is not “finitely distinguishable” but “sequentially distinguishable”. Then we have constructed a practical non‐parametric sequential test for equality of two medians. This sequential procedure converges with probability one. Upper bounds of two types of error probabilities are also calculated.
Exact distribution of product of generalized F‐variates
Authors: Shah M.C. , Rathie P.N.
Published: June 2006

In this paper the exact distributions of products of independent generalized Snedecor's F‐variables have been established in H‐function, G‐function, and in computable form. The exact distributions of products of independent F‐variables, folded Student‐t variables, beta second kind and folded Cauchy variables have also been obtained as particular cases. One particular case is verified with the result available in the literature. Calculus of residues, properties of Meijer's G‐function, Psi function, H‐function and Zeta function are used in deriving the results. Percentage points can be computed directly from the representation given in this article.
Tests unilatéraux multivariés
Authors: Hudon Georges
Published: June 2006

Nous étudions le problème de tester, dans une population normale p‐dimensionnelle de moyenne μ et de matrice de covariance ∑ inconnue, l'hypothèse nulle ℋ︁0: μ1 = 0, μ ≥ 0 versus l'alternative ℋ︁1: μ ≠ 0 ou μ2 ≱ 0, où μ′ =(μ′1, μ′2). Nous dérivons le test à rapport de vraisemblance maximale, nous montrons que le test découlant du principe d'union‐inter‐section est le même, nous démontrons l'admissibilité de ce test, et nous en calculons les valeurs critiques.