bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitochondrial phylogeny and phylogeography of East African squeaker catfishes (Siluriformes: Synodontis)
Authors: Koblmüller Stephan , Sturmbauer Christian , Verheyen Erik , Meyer Axel , Salzburger Walter 
Published: June 2006

AbstractBackgroundSqueaker catfishes (Pisces, Mochokidae,Synodontis) are widely distributed throughout Africa and inhabit a biogeographic range similar to that of the exceptionally diverse cichlid fishes, including the three East African Great Lakes and their surrounding rivers. Since squeaker catfishes also prefer the same types of habitats as many of the cichlid species, we hypothesized that the East AfricanSynodontisspecies provide an excellent model group for comparative evolutionary and phylogeographic analyses.ResultsOur analyses reveal the existence of six major lineages ofSynodontisin East Africa that diversified about 20 MYA from a Central and/or West African ancestor. The six lineages show a clear geographic patterning. Two lineages are endemic to Lake Tanganyika (plus one non-endemic representative), and these are the only twoSynodontislineages that diversified further into a small array of species. One of these species is the cuckoo catfish (S. multipunctatus), a unique brood parasite of mouthbrooding haplochromine cichlids, which seems to have evolved in parallel with the radiation of its cichlid host lineage, the Tropheini. We also detect an accelerated rate of molecular evolution inS. multipunctatus, which might be the consequence of co-evolutionary dynamics.ConclusionWe conclude that the ancestral lineage of today's East African squeaker catfish fauna has colonized the area before the Great Lakes have formed. This ancestor diversified rapidly into at least six lineages that inhabit lakes and rivers in East Africa. Lake Tanganyika is the only lake harboring a small species flock of squeaker catfishes.
The normal human chondro-osseous junctional region: evidence for contact of uncalcified cartilage with subchondral bone and marrow spaces
Authors: Lyons Tim J , McClure Sheena F , Stoddart Robert W , McClure John 
Published: June 2006

Abstract

Background
The chondro-osseous junctional region of diarthrodial joints is peculiarly complex and may be considered to consist of the deepest layer of non-calcified cartilage, the tidemark, the layer of calcified cartilage, a thin cement line (between the calcified cartilage and the subchondral bone) and the subchondral bone. A detailed knowledge of the structure, function and pathophysiology of the normal chondro-osseous junction is essential for an understanding of the pathogenesis of osteoarthrosis.

Methods
Full thickness samples from human knee joints were processed and embedded in paraffin wax. One hundred serial sections (10 μm thick) were taken from the chondro-osseous junctional region of a block from the medial tibial plateau of a normal joint. They were stained with haematoxylin and eosin and photographed. For a simple physical reconstruction images of each 10th sequential tissue section were printed and the areas of the photomicrographs containing the chondro-osseous junctional region were cut out and then overlaid so as to create a three-dimensional (3D) model of this region. A 3D reconstruction was also made using computer modelling.

Results
Histochemical staining revealed some instances where prolongations of uncalcified cartilage, delineated by the tidemark, dipped into the calcified cartilage and, in places, abutted onto subchondral bone and marrow spaces. Small areas of uncalcified cartilage containing chondrocytes (virtual islands) were seen, in two-dimensional (2D) sections, to be apparently entombed in calcified matrix. The simple physical 3D reconstruction confirmed that these prolongations of uncalcified cartilage were continuous with the cartilage of zone IV and demonstrated that the virtual islands of uncalcified cartilage were cross-sections of these prolongations. The computer-generated 3D reconstructions clearly demonstrated that the uncalcified prolongations ran through the calcified cartilage to touch bone and marrow spaces and confirmed that the apparent entombment of chondrocytes was a 2D artefact.

Conclusion
This study demonstrates that the chondro-osseous junctional region is more complex than previously described. The tidemark is a clearly defined boundary delineating uncalcified from calcified cartilage. It is not a straight line across a joint, but a complex three-dimensional structure that follows uncalcified cartilage prolongations dipping down through the calcified cartilage to abut onto subjacent bone or marrow spaces.
The effect of myoglobin concentration on aerobic dive limit in a Weddell seal
Authors: Wright T. J. , Davis R. W. 
Published: June 2006

SUMMARYOne physiological adaptation for prolonged dive duration in marine mammals is an elevated myoglobin (Mb) concentration in skeletal muscle. To determine the influence of Mb concentration on the aerobic dive limit (ADL), we modified a previously published model that simulated aerobic dives in a Weddell seal(Leptonychotes weddellii) and ran it for four Mb concentrations: 5,27, 54 and 108 g Mb kg–1 muscle representing 7%, 50%, 100%and 200%, respectively, of the normal Mb concentration in Weddell seal skeletal muscle. The model was run at increasing levels of muscular exertion and under postabsorptive and postprandial conditions to determine their effect on ADL. For each set of conditions, the model was also run at different levels of cardiac output (i.e. the dive response was varied) to determine the level of convective oxygen transport that optimized the ADL. In a postabsorptive state at a routine level of muscular exertion for a diving Weddell seal, a decrease in Mb concentration to 7% of normal caused a 39% decrease in the ADL(18 min to 11 min), while doubling the Mb concentration increased the ADL by 30% (18 min to 24 min). Under postprandial conditions at a routine level of muscular exertion, doubling the Mb concentration did not increase the ADL (12 min). The convective oxygen transport needed to meet the metabolic demands(Heat Increment of Feeding, HIF) of the splanchnic organs during digestion and assimilation required a cardiac output that was not optimal for the efficient use of muscle oxygen stores. This resulted in an over perfusion of the muscles and incomplete use of myoglobin-bound oxygen. As a result, the postprandial ADL was limited by the amount of oxygen stored in the blood, and increasing the Mb concentration had no effect on the ADL. We hypothesize that myoglobin concentration is optimized for the type and duration of dives routinely made by Weddell seals, and that a further increase may not increase the ADL for most free-ranging dives.
Valence Isomerism between Sterically Protected Methylenephosphine P-Sulfide and 1,2-Thiaphosphirane
Authors: Toyota Kozo , Takahashi Hiroaki , Shimura Kazuho , Yoshifuji Masaaki 
Published: June 2006

Abstract
Reaction of (diphenylmethylene)(2,4,6-tri-t-butylphenyl)phosphine with elemental sulfur afforded 3,3-diphenyl-2-(2,4,6-tri-t-butylphenyl)-1,2-thiaphosphirane 2-sulfide via methylenephosphine P-sulfide. Desulfurization reaction of the thiaphosphirane 2-sulfide with tris(dimethylamino)phosphine gave 3,3-diphenyl-2-(2,4,6-tri-t-butylphenyl)-1,2-thiaphosphirane. Valence isomerization occurred between the methylenephosphine P-sulfide and the thiaphosphirane by heat or by photo-irradiation. The structures of the methylenephosphine, the methylenephosphine P-sulfide, and the thiaphosphirane were analyzed by X-ray crystallography.
Hydrogenation on Supported Lanthanide–Palladium Bimetallic Catalysts: Appearance of Considerable Hydrogen Uptake
Authors: Imamura Hayao , Igawa Koji , Sakata Yoshihisa , Tsuchiya Susumu 
Published: June 2006

Abstract
Upon introducing of lanthanide metals (Ln : Eu or Yb) onto a Pd surface by the reaction of Pd/SiO2 with Eu or Yb metal dissolved in liquid ammonia, the ability of considerable hydrogen uptake by the catalyst appeared during the hydrogenation reaction. Hydrogenation over supported lanthanide–palladium bimetallic catalysts was studied at 173—213 K, especially concerning the effects of the reactants, support materials, Pd particle sizes, and dispersion on the hydrogenation behavior with the hydrogen uptake. For the hydrogenation of ethene, propene, butene or butadiene, considerable hydrogen uptake occurred preferentially, followed by hydrogenation using the hydrogen taken up the catalyst. The hydrogenation occurred by a rate-limited hydrogen uptake process. In marked contrast to olefin and butadiene, no hydrogen uptake was observed for the hydrogenation of acetylene, indicating the progress of the reaction by a different mechanism. The support materials (SiO2, Al2O3, ZrO2, MgO, and TiO2), Pd particle sizes and Pd dispersion in Pd/support were important factors in determining the hydrogen uptake by supported Ln–Pd catalysts and the resulting hydrogenation behavior.
Metalation of Water-Soluble Octabromoporphyrin with Lithium(I), Cadmium(II), and Mercury(II)
Authors: Tabata Masaaki , Nishimoto Jun , Ogata Akiko , Kusano Tohru , Nahar Nurun 
Published: June 2006

Abstract
A water-soluble porphyrin, 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (H2obtpps4−; H2P4−) was synthesized and the equilibrium constants have been determined for the reaction of H2obtpps4− with lithium(I), cadmium(II), and mercury(II) at 25 °C in I = 0.1 mol dm−3 (NaNO3). The protonation constants of H2obtpps4− were found to be 104.83 ± 0.04 mol−1 dm3, 101.96 ± 0.06 mol−1 dm3, and 10−10.02 ± 0.02 mol dm−3 for K1 = [H3P3−][H+]−1[H2P4−]−1, K2 = [H4P2−][H+]−1[H3P3−]−1, and K−1 = [HP5−][H+][H2P4−]−1, respectively. The porphyrin reacted with lithium(I) in alkaline aqueous solution to form LiP5−, of which formation constant was 10−18.81 ± 0.02 mol dm−3 for KLiP = [LiP5−][H+]2[Li+]−1[H2P4−]−1. Sodium and potassium ions did not form their complexes under the same experimental conditions. The equilibrium constants for the formation of cadmium(II) and mercury(II) porphyrins defined by KMP = [MP4−][H+]2[M2+]−1[H2P4−]−1, M = Cd2+; Hg2+, were 10−8.60 ± 0.13 mol dm−3 and 100.12 ± 0.06 mol dm−3 for KCdP and KHgP, respectively. Mercury(II) also forms homodinuclear porphyrin, Hg2P, and the value was 103.57 ± 0.03 mol−1 dm3 for KHg2P = [Hg2P2−][Hg2+]−1[HgP4−]−1. The octabromo groups lower the basicity of the porphyrin, which results in the formation of lithium(I) porphyrin.
Oxidation of Organic Compounds with Tetrabutylammonium Periodate in the Presence of Lewis Acids in Aprotic Organic Solvents
Authors: Firouzabadi Habib , Sardarian Alireza , Badparva Hasan 
Published: June 2006

Abstract
Tetrabutylammonium periodate is able to oxidize alcohols to their carbonyl compounds, α-hydroxy ketones to α-diketones, α-hydroxy carboxylic acids to the carbonyl compounds (accompanied with decarboxylation), thiols to disulfides, thioethers to sulfoxides in CHCl3 and CH3CN in the presence of AlCl3 and BF3·Et2O as catalysts.
Flotation of Uranium from Seawater with Phosphate Esters of C-Undecylcalix[4]resorcinarene
Authors: Koide Yoshifumi , Terasaki Hiroyuki , Sato Hirotaka , Shosenji Hideto , Yamada Kimiho 
Published: June 2006

Abstract
Table-type chelating surfactants ([4]ArmX-R12, mX means the number of phosphates (P), carboxylic acid (Ac), and hydroxamic acid (Hx), respectively) have been derived from the calix[4]resorcinarene bearing tetradodecyl side chains ([4]Ar-R12), and applied to a collector of uranium flotation. The surface tension of the aqueous solution was 35 mN m−1 for [4]Ar5.6P-R6 (Rn means the alkyl chain length), 52 mN m−1 for [4]Ar5.9P-R12, 42 mN m−1 for [4]Ar8.0Ac-R12, and 48 mN m−1 for [4]Ar5.1Hx-R12. They formed UO2 complexes and floated the UO22+ from an aqueous solution by air-bubbling. Furthermore, [4]Ar5.9P-R12 and [4]Ar6.3P-R12 had competence to float the uranium from seawater. A trace amount of uranium in 450 cm3 of seawater was floated at 68—94% using 1—10 mg of [4]Ar5.9P-R12 or [4]Ar6.3P-R12. On the other hand, [4]Ar5.1Hx-R12 and [4]Ar8.0Ac-R12 brought about lower floatabilities. [4]ArmP-R12 could be recycled several times by dissolving the scum (uranium complex) in 5 mol dm−3 H2SO4.
Prosthodontic Self-treatment With Acrylic Resin Super Glue: A Case Report
Authors: Winkler Sheldon , Wood Robert , Facchiano Anne M. , Boberick Kenneth G. , Patel Amita R. 
Published: June 2006

AbstractA case history is presented of a patient who fabricated 3 prostheses from autopolymerizing acrylic resin intended for fingernail augmentation and then cemented them into her mouth with super glue. Patients must be warned not to attempt self-treatment for esthetics with self-fabricated prostheses because severe adverse and irreversible hard and soft tissue reactions may occur.
Further identities for the Wishart distribution with applications in regression
Authors: Haff L. R. 
Published: June 2006

AbstractMatrix analogues are given for a known scalar identity which relates certain expectations with respect to the Wishart distribution. (The scalar identity was independently derived by C. Stein and L. Haff.) The matrix analogues are more aptly called “matrix extensions.” They can be derived by using the scalar identity; nevertheless, they are seen (in quite elementary terms) to be more general than the latter. A method of doing multivariate calculations is developed from the identities, and several examples are worked in detail. We compute the first two moments of the regression coefficients and another matrix arising in regression analysis. Also, we give a new result for the matrix analogue of squared multiple correlation: the bias correction of Ezekiel (1930), a result often used in model building, is extended to the case of two or more dependent variables.
A measure of aliasing and applications to two‐level fractional factorials
Authors: Monette Georges 
Published: June 2006

AbstractThis paper examines some properties of a measure of aliasing proposed by Hedayat, Raktoe, and Federer (1974). It is shown that in the case of balanced orthogonal designs with no repeated treatments, minimizing the alias measure is equivalent to minimizing tr Yar(ψ). Lower bounds are found for fixed eigenvalues of the design matrix. These results are applied to two‐level fractional factorials to show that in certain cases classical fractional‐factorial designs yield minimal solutions for the alias measure.
Estimation of the mean of an exponential distribution in the presence of an outlier
Authors: Chikkagoudar M. S. , Kunchur S. H. 
Published: June 2006

AbstractKale and Sinha (1971) have found an estimator of the mean of an exponential distribution in the présence of an outlying observation with higher expected value. Here an alternative estimator of the mean is proposed and it is compared with the estimator of Kale and Sinha (1971) and the maximum likelihood estimator given by Kale (1975). The proposed estimator is found to be more efficient than the latter two estimators in some cases.
Rules for multiplication of any polykay by polykay products of weight 5
Authors: Nagambal P.N. , Tracy Derrick S. 
Published: June 2006

AbstractNagambal and Tracy [1] provided rules for multiplication of any polykay by another of weight 5. In [2], they proposed similar rules for multiplying a polykay by polykay products of weight 5. Here all such rules are présentés explicitly.
Spectral properties of the concurrent and forecasting seasonal linear filters of the X‐11‐ARIMA method
Authors: Dagum Estela Bee 
Published: June 2006

AbstractThis study analyzes the properties of the linear filters of the X‐11‐ARIMA seasonal adjustment method applied for current seasonal adjustment. It provides the general formula for the combined weights that result from the ARIMA model extrapolation filters with the X‐11 seasonal‐adjustment filters. The three cases studied correspond to the three ARIMA models automatically tested by the X‐11‐ARIMA program, namely, (0, 1, 1)(0, 1, 1), (0, 2, 2)(0, 1, 1), and (2, 1. 2)(0, 1,1). The parameter values chosen reflect different degrees of flexibility of the trend‐cycle and seasonal components. It is shown that the X‐11‐ARIMA linear filters for current seasonal adjustment are very flexible; they change with both the ARIMA extrapolation model and its parameter values, contrary to those of the X‐11 program, which are fixed for a given set of options.
Two‐moment approximations to some null distributions in order‐restricted inference: Unequal sample sizes
Authors: Singh Bahadur , Wright F. T. 
Published: June 2006

AbstractBartholomew's statistics for testing homogeneity of normal means with ordered alternatives have null distributions which are mixtures of chi‐squared or beta distributions according as the variances are known or not. If the sample sizes are not equal, the mixing coefficients can be difficult to compute. For a simple order and a simple tree ordering, approximations to the significance levels of these tests have been developed which are based on patterns in the weight sets. However, for a moderate or large number of means, these approximations can be tedious to implement. Employing the same approach that was used in the development of these approximations, two‐moment chisquared and beta approximations are derived for these significance levels. Approximations are also developed for the testing situation in which the order restriction is the null hypothesis. Numerical studies show that in each of the cases the two‐moment approximation is quite satisfactory for most practical purposes.
Least‐squares estimation of transition probabilities from aggregate data
Authors: Kalbfleisch J. D. , Lawless J. F. 
Published: June 2006

AbstractConsider a population of n individuals that move independently among a finite set {1, 2,……, k} of states in a sequence of trials. t = 0. 1, 2,…, m. each according to a Markov chain with transition probability matrix P. This paper deals with the problem of estimating P on the basis of aggregate data which record only the numbers of individuals that occupy each of the k states at times t = 0. 1,2,……,m. Estimation is accomplished using conditional least squares, and asymptotic results are verified for the case n → ∞. A weighted least‐squares estimator is introduced and compared with previous estimators. Some comments are made on estimability questions that arise when only aggregate data are available.
First passage game
Authors: Nair K. P. K. , Laughland A. R. , Srinivasan S. 
Published: June 2006

AbstractAppealing to the theory of stochastic games, a two‐person, zero‐sum first passage game, which may be viewed as a generalization of the first passage decision problem, is developed. In the first passage game, the players have stationary optional strategies and the values are unique and these can be computed using an algorithm for terminating stochastic games. It is also shown that the solution of a recurrence game is closely related to that of the first passage game. Finally, it is shown that a finite step stochastic game with nonstationary transition probabilities and payoffs can be converted to a first passage game whose solution yields a solution of the original finite step game. The first passage game so obtained has stationary transition probabilities and payoffs. Because of its special structure, the solution method reduces to a dynamic programming recursion in the context of games.
Convergence faible sur des espaces topologiques uniformes et suites aléatoires d'éléments aléatoires
Authors: Kohler Boris 
Published: June 2006

AbstractAprès quelques résultats de convergence faible, nous donnons des théorèmes de selection pour des éléments aléatoires sur des espaces uniformes. Nous rattachons un théorème de Fernandez (1971, p. 1740) á ces résultats.
Comparison of two measures of association in two‐way contingency tables
Authors: Hamdan M. A. 
Published: June 2006

AbstractStuart's (1953) measure of association in contingency tables, tC, based on Kendall's (1962) t, is compared with Goodman and Kruskal's (1954, 1959, 1963, 1972) measure G. First, it is proved that |G| ≥ |tC|; and then it is shown that the upper bound for the asymptotic variance of G is not necessarily always smaller than the upper bound for the asymptotic variance of tC. It is proved, however, that the upper bound for the coefficient of variation of G cannot be larger in absolute value than the upper bound for the coefficient of variation of tC. The asymptotic variance of tC is also derived and hence we obtain an upper bound for this asymptotic variance which is sharper than Stuart's (1953) upper bound.
Sampling a finite population in the presence of trend and correlation: Estimation of total 305‐day lactation production in cattle
Authors: Bartlett Roy F. 
Published: June 2006

AbstractThis paper studies the estimation of a finite population total in the presence of trend. A practical problem of dairy science is to estimate a cow's total 305‐day milk production given a number of test‐day records. We analyze this problem as one of estimating the total of a discrete population when the population values are correlated and exhibit a trend over time. Linear prediction estimators that are BLUE for known covariance and trend function linear in unknown parameters were applied to the estimation of the milk yield total. An empirical study compares BLUE with the expansion estimator and the procedure currently used by the Canadian Record of Performance for Dairy Cattle.
The distribution of random determinants
Authors: Alagar V. S. 
Published: June 2006

AbstractThe exact distribution of |Δn| where Δn is a random determinant with independent and identically distributed exponential elements is given for the cases n = 2 and 3. From the investigation of the behaviour of the density functions for these cases it is conjectured that for any fixed n, the probability density of |Δn| for large values of the argument is the same as the density of (Y/n)n, where Y is a gamma random variable.
An infinite class of PBIB designs
Authors: Saha G. M. , Das A. D. 
Published: June 2006

AbstractIn this paper, an infinite class of partially balanced incomplete block (PBIB) designs of m+1 associate classes is constructed through the use of a series of row‐orthogonal matrices known as partially balanced orthogonal designs (PBOD) of m‐associate classes. For the purpose, a series of PBOD is obtained through a method described herein. An infinite class of regular GD designs is also reported.
Young chains and rank orders
Authors: Narayana T. V. , Savage I. Richard , Saxena K. M. Lal 
Published: June 2006

AbstractSavage (1956) obtained an easily applied necessary condition for the admissibility of two‐sample rank tests under alternatives having a monotone likelihood ratio. This condition is: rank order Z is more likely than rank order Z' if the Z‐path is above the Z'‐path in Young's lattice. This condition is easily applied and allows not only the proof of the inadmissibility of the Wilcoxon test under Lehmann alternatives but it can also be used to construct explicitly uniformly better tests. For Lehmann alternatives, we obtain another necessary criterion on rank orders which makes use of dominance.