bluuebunny/crossref_metadata_2025 huggingface dataset:
Etude de la teneur en DNA nucléaire dans le méristème apical des tiges du Celosia cristata (Amarantacées) en fonction de la photopériode
Authors: Driss-Ecole D.
Published: November 2007

Two samples of plants of Celosia cristata, a quantitative short-day plant, were grown in an 8-h or a 16-h day. The shoot apices were collected at 11, 15, 18, and 28 days in order to carry out a cytophotometric study of the nuclear DNA in the corpus. This distribution of the DNA values was analyzed statistically using the χ2 test. At the beginning of development, for both 8-h day and 16-h day plants, the DNA content of the majority of the nuclei is at the 2C level. Then the percentage 2C–4C or 4C nuclei increases, slowly for the plants grown under a 16-h photoperiod and quickly for the others. At the 28th day, the Gaussian distribution of DNA values indicates that the state reached by the meristems is quite different. Between the 18th day and the 28th day of culture, ontogenesis of the shoot apex goes through a critical period. At the end of this period, shoot apices of the plants grown under a 16-h photoperiod are in the intermediate phase with a majority of nuclei in the synthetic phase (S) or in the postsynthetic phase (G2). Simultaneously, structural modifications of the axial zone give rise to a central zone characteristic of the fasciation of the shoot apex. In plants grown with an 8-h photoperiod, the shoot apex goes through the prefloral phase with more numerous nuclei in the presynthetic phase (G1) or in the synthetic one (S). For each sample the nuclei clustered in a particular phase of the cell cycle indicate that a certain synchronism of the cell cycles in the corpus takes place. These results are compared with those recently obtained by other authors working with different plants.
Pollen development in male-fertile and cytoplasmic male-sterile rye
Authors: Scoles G. J. , Evans L. E.
Published: November 2007

Pollen development in a male-fertile and a cytoplasmic male-sterile line of rye (Secale cereals L.) was investigated using histological techniques. In the male-fertile line a high degree of organization was evident within the locule, and polarity within the microspore was also apparent. In the male-sterile line, development appeared to proceed normally until the tetrad stage. Just after tetrad breakup, the tapetum became vacuolate and invaded the locule. Two days later the organization within the locule had broken down completely. Microspores and tapetum had become an unorganized mass within the locule. By 10 days after tetrads, the middle layer had also broken down. At dehiscence the contents of the locule remained as a compressed layer over the endothecium of the anther.
Analyse écologique du phytoplancton de trois lacs des Laurentides (Québec, Canada)
Authors: Plinski Marcin , Magnin Etienne
Published: November 2007

Water and phytoplankton samplings were taken in three little Laurentide lakes from July 4, 1972, to October 29, 1973. Of the 111 species identified, 66 are found in Lake Triton (maximum depth 3 m, pH 6.8, conductivity 30 μmhos/cm; 1 mho = 1 S), 62 in Lake Geai (6 m, pH 5.8, 22 μmhos/cm) and 47 in Lake Croche (8 m, pH 6.5, 25 μmhos/cm). The greatest number of species belong to Diatoms and Desmidiaceae. However, the most numerous algae are Chrysophyceae, at least in some months of the year in the three lakes, and Cyanophyceae in Lake Geai.
Effects of nitrogen fertilization on growth and ectomycorrhizal formation of Quercus alba, Q. rubra, Q. falcata, and Q. falcata var. pagodifolia
Authors: Beckjord Peter R. , Melhuish Jr. John H. , McIntosh Marla S. , Hacskaylo Edward
Published: November 2007

Quercus alba, Q. rubra, Q. falcata, and Q. falcata variety pagodifolia seedlings were grown for 105 or 110 days in containers in a greenhouse in a medium with and without vegetative or basidiospore inoculum of the ectomycorrhizal fungi Pisolithus tinctorius and Scleroderma auranteum. At 15 days after planting acorns, nitrogen in the form of sodium nitrate or ammonium chloride was added to each container at the rates of 0.0 or 100 mg nitrogen per seedling. Growth of all Quercus seedlings that were not fertilized was significantly less than seedlings fertilized with nitrate or ammonium nitrogen (100 mg N). Ectomycorrhizal development of all Quercus seedlings that were not fertilized or fertilized with sodim nitrate (100 mg N) was significantly less than seedlings fertilized with ammonium chloride (100 mg N). Ectomycorrhizal development of oak species varied with different mycorrhizal inocula.
Protoplasmic changes during stomatal development in Funaria
Authors: Sack Fred D. , Paolillo Jr. D. J.
Published: November 2007

Key protoplasmic features of stomatal development in Funaria hygrometrica Hedw. (Musci) were characterized using light and electron microscopy. Endoplasmic reticulum (ER) cisternae are initially rough and often arranged in parallel arrays. During pore formation, the cytoplasm becomes packed with tubular, smooth ER. Older but still functional stomata contain small amounts of primarily cisternal ER. Lipid bodies decrease in electron density when tubular ER appears. Preliminary observations indicate that two large vacuoles occupy the polar regions of open, but not closed, stomata. Intact plasmodesmata occur in developing but not mature walls. Plastid structure, microtubule distribution, and other protoplasmic features are essentially similar to those described in the stomata of other genera.
Action of gibberellic acid in effecting phase shifts of the circadian leaf-movement rhythm of a cotton plant, Gossypium hirsutum
Authors: Viswanathan N. , Subbaraj R.
Published: November 2007

Pulses of gibberellic acid (GA3) offered at various phases of circadian leaf-movement rhythms in the cotton plant, Gossypium hirsutum, effected advance phase shifts of varying magnitude. Neither the quality nor the amount of these phase shifts was altered by the background illumination, suggesting an apparent absence of synergistic action of the light and gibberellic acid.
Developmental responses in tetraploid wheat (Triticum turgidum)
Authors: Flood R. G. , Halloran G. M.
Published: November 2007

Nineteen lines of tetraploid wheat (Triticum turgidum) were examined for the presence and strength of developmental responses in the field during 1980 and 1981 and compared with lines of known vernalization and photoperiod responses in the hexaploid wheat (Triticum aestivum). Five of them had stronger vernalization responses than the winter habit hexaploid line cv. Triple Dirk C. Strong vernalization response of the tetraploids was usually associated with photoperiod insensitivity and vice versa although several lines had a combination of high photoperiod sensitivity and moderate levels of vernalization response. Compared with hexaploids the tetraploids exhibited much more variation in spikelet number per head following vernalization treatment which was less marked in some of the domesticated lines. Speculations are made on the genetic control of vernalization response in tetraploid wheat and the possible significance of greater stability in the expression of spikelet number in the evolution of wheat.
An ultracytochemical study of the nucleoplasm in meristematic plant cell (Allium porrum) interphase nuclei
Authors: Luck B. T. , Lafontaine J. G.
Published: November 2007

In conventionally processed specimens, the nucleoplasm of plant reticulate interphase nuclei consists of a mixture of fibrils and granules of varying sizes. The degree of granularity of the nucleoplasm varies, however, with the fixative used. The finest texture of the nucleoplasm is provided by osmium tetroxide fixation, but judging by its greater transparency, material is undoubtedly extracted. In specimens fixed with glutaraldehyde only evidence of clumping of the nucleoplasm is observed. The nucleoplasm exhibits a finer, less granular texture following postfixation with osmium tetroxide. Although extraction of nucleoplasmic material is noted in samples fixed in formaldehyde, a much improved preservation is obtained when this fixative is used with osmium tetroxide. Following preservation with these two fixatives and staining en bloc with bismuth the ultrastructural characteristics of the nucleoplasm are particularly well revealed. Apart from fine fibrillar material permeating the nucleoplasmic zones, a large population of granules of different sizes is also observed. Part of the material may be shown, using phosphotungstic acid staining, to consist of diffuse chromatin. The fact, however, that the nucleoplasm also contains much RNA-containing structural elements is revealed by the persistence of a coarse interchromatin reticulum after extraction of specimens with deoxyribonuclease and staining with 3,3′-diaminobenzidine.
Structure and biology of a new Tolypocladium attacking bdelloid rotifers
Authors: Barron G. L.
Published: November 2007

Tolypocladium lignicola is described as new. The asymmetrical conidia lodge in the mastax of bdelloid rotifers and germinate to produce assimilative infection hyphae composed of elongate, clavate to turbinate, assimilative cells. Conidial production is prolific in air but suppressed under water.
Lectotypification of Glomus macrocarpum and proposal of new combinations: Glomus australe, Glomus versiforme, and Glomus tenebrosum (Endogonaceae)
Authors: Berch Shannon M. , Fortin J. André
Published: November 2007

A lectotype is designated for Glomus macrocarpum Tul. & Tul. from the original Tulasne collections. As a consequence of the examination of type materials of previously proposed synonyms of this species, three new combinations are made: Glomus australe (Berk.) Berch, Glomus versiforme (Karst.) Berch, and Glomus tenebrosum (Thaxter) Berch.
Photosynthetic patterning: a mechanism for sun tracking
Authors: Fisher F. J. F. , Fisher P. M.
Published: November 2007

Vectorial light detection, a major process in reversible sun tracking (unexplained by phototropic growth responses) is attributed to photosynthate differentials in the leaf. Evidence is provided that movements of the leaf of Lavatera cretica L. (Malvaceae), directly mediated by turgor changes in supporting tissues, are triggered by photosynthate gradients across the pulvinar phloem. These solute asymmetries are inferred from starch deposition asymmetries found in the lamina after oblique illumination. Starch patterns correspond precisely with characteristics of leaf-surface topography which cause incident light effectiveness for photosynthesis to change differentially with light direction.
An ultrastructural study of the late-blight fungus Phytophthora infestans and its interaction with the foliage of two potato cultivars possessing different levels of general (field) resistance
Authors: Coffey Michael D. , Wilson Una E.
Published: November 2007

In the susceptible reaction of foliage of the cultivar Majestic there was extensive colonization of the host tissue prior to the onset of necrosis. The development of intracellular hyphae was confined to the initially parasitized palisade cells. Thereafter the fungus grew as intercellular hyphae, which penetrated host cells and formed haustoria. Haustorial morphology was highly variable, ranging in type from small spherical to much larger digitlike structures. Haustorial formation was preceded by the laying down of a moderately electron-dense penetration matrix bounded by the host plasmalemma. This material probably constituted the extrahaustorial matrix once haustorial development had taken place. The matrical material stained with silver proteinate reagent, and this reaction was blocked by dimedone, indicating that it was carbohydrate in nature. In the resistant reaction of foliage of the cultivar Shamrock, the epidermal cells rapidly became necrotic. Quantities of exceedingly electron-dense granules appeared in the necrotic host cells. Host organelles were no longer recognizable, but the fungal cytoplasm remained intact. In adjoining host cells, thin cell wall appositions were formed, which had a heterogeneous composition. On occasions when the fungus attempted to invade an underlying mesophyll cell, papillae usually formed in that cell at the site of incipient penetration.
La morphogénèse du calice de Fittonia vershaffeltii. Données biométriques
Authors: Ferrand Aude , Cusset Gérard
Published: November 2007

A biometrical study of the calyx of 178 flowers of Fittonia vershaffeltii at all developmental stages has allowed conclusions to be drawn about their morphogenesis. Their various parts grow according to simple allometric relations, and this growth is linked with the cauline plastochron. The equations are presented together with a numerical study of parameters. The tube and the lobe of each sepal can be initiated separately, and their fate would depend essentially on the orientations of mitotic divisions. These data are interpreted in relation to various theories on the morphogenesis of the calyx. [Journal translation]
Relation between photosynthetic starch formation and dry-weight partitioning between the shoot and root
Authors: Huber Steven C.
Published: November 2007

The possible relationship of partitioning of photosynthate between starch and sucrose to the distribution of dry weight between the shoot and root was examined in relation to genetic variation and plant nutritional status. Soybean (Glycine max (L.) Merr.), tobacco (Nicotiana tabacum L.), and red-beet (Beta vulgaris L.) seedlings had low relative root weights and accumulated high levels of leaf starch, whereas the reverse was true for wheat (Triticum aestivum L.) seedlings. A similar relationship between starch formation and relative root weight was observed in comparisons among six peanut (Arachis hypogea L.) cultivars and with 'Ransom' soybean and two peanut cultivars exposed to a variety of nutritional treatments. The results suggested that carbon partitioned into leaf starch was preferentially utilized for growth of shoots at night. The postulate was supported by diurnal dry-weight changes of various parts of 'Ransom' soybean plants. Stems and expanding leaves increased in dry weight at about the same rate both during the day and night, whereas roots increased in dry weight during the day but during the night lost about 50% of the dry weight gain. Hence, of the total carbohydrate received by roots over a 24-h period, relatively more material was apparently obtained during the day. Overall, the results suggested that partitioning of carbon between starch and sucrose in the leaf may be one of the factors that affects the growth of shoots relative to roots.
Fossil seed cuticles from the Upper Cretaceous Whitemud beds of Alberta and Saskatchewan, Canada
Authors: Binda Pier L. , Nambudiri E. M. V.
Published: November 2007

Abundant fossil cuticles are associated with megaspores in the Upper Cretaceous Whitemud beds of the southern Alberta plains and in the Whitemud Formation of the Cypress Hills. Form genera Spermatites Miner and Costatheca (Dijkstra) Hall are emended, and the new genus Carpotheca is described. The three genera are differentiated by shape and orientation of cuticular cells. Ten new species of seed cuticles are described. The affinity of Spermatites with the extant genus Juncus L. is reaffirmed, and it is suggested that Costatheca may be related to extant species of Butomus L. In the Whitemud, Costatheca is more abundant in the Alberta plains, whereas Spermatites and Carpotheca are better represented in the Cypress Hills. The fossil microfloral assemblage indicates that these beds were deposited in a continental, fluviatile to lacustrine environment, having a subtropical climate, in agreement with previous sedimentological, isotopic, and palynological investigations.
Morphometrics and ecological isolation in sympatric Spiranthes (Orchidaceae) in southwestern Ontario
Authors: Catling P. M. , Brown J. R.
Published: November 2007

To determine the extent to which three Spiranthes taxa are distinct and the extent to which they are isolated in a region of close sympatry, morphological and ecological data were collected for each of 251 flowering plants selected from 22 stations in southwestern Ontario. The morphological data, consisting of 36 quantitative characters per plant, were subjected to statistical analysis to allow an objective classification into groups and the ecological data were subsequently evaluated in terms of these groups. Three morphological groups obtained by principal-component analysis corresponded to three subjectively determined flower-color categories and are referable to S. cernua, S. magnicamporum, and S. ochroleuca. Clustering of distance coefficients followed by discriminant analysis of major divisions also produced the same three morphological groups, but the separation was more obvious. Possible hybrids involving S. cernua, with either of the other taxa, were infrequent (11 of 251). Further discriminant analysis using population samples from the region of sympatry along with topotype population samples of two of the taxa revealed no character convergence, but some character displacement was suggested. Interpopulation variation was least in plants referable to the agamospermic S. cernua and maximal in the group referable to the sexual S. ochroleuca. The best characters for separating the three groups in the region of sympatry are the same characters employed over a broad geographical area. Spiranthes ochroleuca and S. magnicamporum were shown to be isolated by soil pH. Although S. cernua has a broad pH tolerance, it was found to be isolated from S. ochroleuca and S. magnicamporum by its earlier flowering time and preference for moist sites. Ecological discreteness of the three Spiranthes was further demonstrated by coordinate analysis of distance and Jaccard's coefficients for various plant associates. Other potential isolating mechanisms which may also contribute to the three distinctive morphologies are discussed. Taxonomic recognition at the species level is supported.
Differences in the flowering requirements of widespread populations of Rumex crispus
Authors: Hume L. , Cavers P. B.
Published: November 2007

Clonal individuals of 10 plants of Rumex crispus L. from each of six populations were planted in experimental gardens in College Station, TX; St. Louis, MO; and London, Ont., in 1975. Two of the populations were from Ontario and one each was from Indiana, Tennessee, Louisiana, and Texas. In College Station most plants from the four northern populations survived for a year, but none flowered. In contrast, 80% of all the plants from Louisiana and Texas flowered in 1976. At the two other gardens all plants of five populations flowered in 1976, while the plants from the most southern populations (Louisiana) suffered 30% mortality before the 1976 flowering period. We conclude that there are differences between populations and within some populations in requirements for flowering that relate to vernalization and (or) photoperiod.
A new species of Sphaerophragmium on Monodora brevipes from Nigeria
Authors: Eboh Dan O.
Published: November 2007

Sphaerophragmium annulatipes, which parasitizes Monodora brevipes Benth. (Anonaceae), is described as a new species and the 18th species of Sphaerophragmium. It is characterized by possessing numerous, sharply pointed projections on the teliospore wall and stout, carotiform, pedicels with annularly rugose walls.
PHYSICAL QUANTITATIVE ANALYSIS IN IN-AIR PIXE
Authors: SERA K. , TERASAKI K. , ITOH J. , SAITOH Y. , FUTATSUGAWA S.
Published: November 2007

A physical method of quantitative analysis for in-air PIXE has been established. Among the three parameters required for performing physical analysis, X-ray production cross sections were recalculated by using the effective energy of the proton beam after losing its energy through a Kapton foil and in air. Detection efficiencies of the Si ( Li ) detector have been determined according to our method established for in vacuum system, where effects of absorption of X-rays in air are incorporated into the detection efficiencies. As a result, it is confirmed that the present method gives us accurate results in the analyses of standard samples as well as actual samples such as soil and ash. It becomes possible to perform quantitative analysis of various samples by optimizing the measuring conditions depending on the samples.
A PHANTOM TEST OF PROTON-INDUCED DUAL-ENERGY X-RAY ANGIOGRAPHY USING IODINATED CONTRAST MEDIA
Authors: OGURI Y. , HASEGAWA J. , OGAWA M. , KANEKO J. , SASA K.
Published: November 2007

Characteristic-line radiation from heavy metal targets bombarded by MeV proton beams has been tested as an X-ray source for dual-energy K-edge subtraction imaging for human angiography (blood vessel imaging) based on iodinated contrast media. To utilize the strong absorption by iodine (Z = 53) at its K-absorption edge (33.2 keV), we used K α-line of La (lanthanum, Z = 57) at 33.4 keV. As a reference, also K α X emission of Sn (tin, Z = 50) at 25.2 keV was employed. Metallic plates of La and Sn were irradiated by 7-MeV protons to produce these characteristic X-rays. Energy-subtraction method was tested using Lucite phantoms which contain aqueous solutions of KI (potassium iodide) with different concentrations. Also Ca ( H 2 PO 4)2 powder was stuffed in these phantoms to simulate bones. The transmission images of the phantoms were recorded on imaging plates. During the exposure, the energy spectra of the X-rays were monitored by a CdTe detector. We found that the contrast of images of iodide solutions taken with La X-rays was higher than that with Sn X-rays. Also the energy subtraction procedure was successfully applied to reduce the graphical noise due to the bones and inhomogeneity of the soft tissue. However, to apply the present method to actual clinical use, the X-ray intensity must be increased by several orders of magnitude. Also the transmission of the “lower-energy” photons has to be a few orders higher for imaging of objects as thick as human chest.
DEVELOPMENT OF MICROBEAM SCANNING SYSTEM
Authors: OYAMA R. , MATSUYAMA S. , ISHII K. , YAMAZAKI H. , KIKUCHI Y. , INOMATA K. , WATANABE Y. , ISHIZAKI A. , KAWAMURA Y. , YAMAGUCHI T. , MOMOSE G.
Published: November 2007

We developed a new microbeam scanning system for efficient local area analyses and also for micro fabrication. The system accomplished a pattern-to-pattern spacing procedure, in which the microbeam was just scanned with a corresponding pattern of the analyzing sample area or of the fabrication form. Between the patterns, the beam was moved with the fastest responsive scanning speed. In order to set patterns of the analyzing sample in the scanning system, an image of the sample was previously obtained with a scanning transmission ion microscopy (STIM). As the result, analyzing time was greatly reduced for the cell sample in which cells are not distributed all over. To demonstrate the scanning system for micro fabrication, such as proton beam writing (PBW). Patterns which were translated from bitmap data including color scale were inscribed on thin films.
IN-VIVO ELEMENTAL ANALYSIS BY PIXE-μ-CT
Authors: KAWAMURA Y. , ISHII K. , YAMAZAKI H. , MATSUYAMA S. , KIKUCHI Y. , YAMAGUCHI T. , WATANABE Y. , OYAMA R. , MOMOSE G. , ISHIZAKI A. , TSUBOI S. , YAMANAKA K. , WATANABE M.
Published: November 2007

We have developed “micron-CT”, using micro-PIXE for in-vivo imaging. This system comprises an X-ray CCD camera (Hamamatsu photonics C8800X9) with high resolution (pixel size: 8×8 μm 2, number of pixels: 1000×1000) and an X-ray-point-source with a spot size of 1.5×1.5 μm 2 which is generated by irradiation of a microbeam on a pure metal target. Thus we can acquire projection data with high resolution. The sample is placed in a small diameter tube and is rotated by a stepping motor. The 3D images were reconstructed from the obtained projection data by using cone-beam CT reconstruction algorithm. X-ray spectra produced by heavy charged particle bombardment, exhibit a much smaller continuous background compared to electron bombardment. Therefore, X-rays produced by ion beam can be used as a monochromatic and low energy X-ray source. The feature is very effective to investigate small insects. Moreover we can get elemental distribution image of object by choosing appropriate characteristic X-rays corresponding to the absorption edge. On the other hand, the conventional X-ray CT, in which continuous X-rays are used, provides images of the electron density in the object. Using this system, we were able to get 3D images of a living ant's head with 6 μm spatial resolution. By using Fe - K -X-rays (6.40 keV) and Co - K -X-rays (6.93 keV), we can investigate the 3D distribution of Mn ( K -absorption edge = 6.54 keV) in an ant's head.
PRIMITIVITY OF FINITE SEMIFIELDS WITH 64 AND 81 ELEMENTS
Authors: HENTZEL I. R. , RÚA I. F.
Published: November 2007

A finite semifield D is a finite nonassociative ring with identity such that the set D* = D \{0} is a loop under the product. Wene conjectured in [1] that any finite semifield is either right or left primitive, i.e. D* is the set of right (or left) principal powers of an element in D. In this paper we study the primitivity of finite semifields with 64 and 81 elements.
PRIMES OF HEIGHT ONE AND A CLASS OF NOETHERIAN FINITELY PRESENTED ALGEBRAS
Authors: GOFFA ISABEL , JESPERS ERIC , OKNIŃSKI JAN
Published: November 2007

Constructions are given of Noetherian maximal orders that are finitely presented algebras over a field K, defined by monomial relations. In order to do this, it is shown that the underlying homogeneous information determines the algebraic structure of the algebra. So, it is natural to consider such algebras as semigroup algebras K[S] and to investigate the structure of the monoid S. The relationship between the prime ideals of the algebra and those of the monoid S is one of the main tools. Results analogous to fundamental facts known for the prime spectrum of algebras graded by a finite group are obtained. This is then applied to characterize a large class of prime Noetherian maximal orders that satisfy a polynomial identity, based on a special class of submonoids of polycyclic-by-finite groups. The main results are illustrated with new constructions of concrete classes of finitely presented algebras of this type.
RECONSTRUCTION OF 5D COSMOLOGICAL MODELS FROM RECENT OBSERVATIONS
Authors: ZHANG CHENGWU , XU LIXIN , PING YONGLI , LIU HONGYA
Published: November 2007

We use a parameterized equation of state (EOS) of dark energy to a 5D Ricci-flat cosmological solution and suppose the universe contains two major components: dark matter and dark energy. Using the recent observational datasets: the latest 182 type Ia Supernovae Gold data, the three-year WMAP CMB shift parameter and the SDSS baryon acoustic peak, we obtain the best fit values of the EOS and two major components' evolution. We find that the best fit EOS crosses -1 in the near past where z ≃ 0.07, the present best fit value of wx(0) < -1 and for this model, the universe experiences the acceleration at about z ≃ 0.5.
CONSTRAINTS ON UED KK-NEUTRINO DARK MATTER FROM MAGNETIC DIPOLE MOMENTS
Authors: FLACKE THOMAS , MAYBURY DAVID W.
Published: November 2007

Generically, universal extra dimension (UED) extensions of the standard model predict the stability of the lightest Kaluza–Klein (KK) particle and hence provide a dark matter candidate. For UED scenarios with one extra dimension, we model-independently determine the size of the induced five-dimension magnetic dipole moment of the KK-neutrino, ν(1). We show that current observational bounds on the interactions of dipole dark matter place constraints on UED models with KK-neutrino dark matter.
THE GENERALIZED CHAPLYGIN GAS MODEL WITH INTERACTION
Authors: WU YABO , LI SONG , ZHONG HAI YANG , LI LEI
Published: November 2007

A two-fluid generalized Chaplygin gas (GCG) model including two different cases is considered in this paper. Concretely, the evolution of the GCG model with interaction is discussed and the statefinder diagnostic for the GCG models is performed, respectively. By analysis, we show that the effective state parameter of dark energy can cross the so-called phantom divide ω = -1, the behavior of GCG will be like ΛCDM in the future and therefore our Universe will not end up with the Big Rip in the future. In addition, we find that the statefinder diagnostic can differentiate the GCG model with or without interaction. Also, trajectories of both the GCG model mixed with cold dark matter (CDM) and the pure GCG model in the parameter plane are illustrated to be significantly different.
A MISSION TO TEST THE PIONEER ANOMALY: ESTIMATING THE MAIN SYSTEMATIC EFFECTS
Authors: BERTOLAMI O. , PÁRAMOS J.
Published: November 2007

We estimate the main systematic effects relevant in a mission to test and characterize the Pioneer anomaly through the flight formation concept, by launching probing spheres from a mother spacecraft and tracking their motion via laser ranging.
NON-COMMUTATIVE BIANCHI QUANTUM COSMOLOGY
Authors: GUZMÁN W. , ORTIZ C. , SABIDO M. , SOCORRO J. , AGÜERO MAXIMO A.
Published: November 2007

Introducing non-commutative variables in the minisuperspace, we obtain the non-commutative quantum solutions to the Wheeler–DeWitt equation with an arbitrary factor ordering, for the anisotropic Bianchi type I cosmological model, coupled to barotropic matter and cosmological term Λ. From the probability density, the inclusion of non-commutativity seems to retard the isotropization of the universe.
CHAOTIC ACCRETION IN A NON-STATIONARY ELECTROMAGNETIC FIELD OF A SLOWLY ROTATING COMPACT STAR
Authors: MIRZA BABUR M.
Published: November 2007

We investigate charge accretion in the vicinity of a slowly rotating compact star with a non-stationary electromagnetic field. Exact solutions to the general relativistic Maxwell equations are obtained for a star formed of a highly degenerate plasma with a gravitational field given by the linearized Kerr metric. These solutions are used to formulate and then to study numerically the equations of motion for a charged particle in the star's vicinity using the gravitoelectromagnetic force law. The analysis shows that close to the star, charge accretion does not always remain ordered. It is found that the magnetic field plays the dominant role in the onset of chaos near the star's surface.
ENERGY SPOT PRICE MODELS AND SPREAD OPTIONS PRICING
Authors: HIKSPOORS SAMUEL , JAIMUNGAL SEBASTIAN
Published: November 2007

In this article, we construct forward price curves and value a class of two asset exchange options for energy commodities. We model the spot prices using an affine two-factor mean-reverting process with and without jumps. Within this modeling framework, we obtain closed form results for the forward prices in terms of elementary functions. Through measure changes induced by the forward price process, we further obtain closed form pricing equations for spread options on the forward prices. For completeness, we address both an Actuarial and a risk-neutral approach to the valuation problem. Finally, we provide a calibration procedure and calibrate our model to the NYMEX Light Sweet Crude Oil spot and futures data, allowing us to extract the implied market prices of risk for this commodity.
A SIMPLE AMERICAN OPTION PRICING METHOD USING THE FAST FOURIER TRANSFORM
Authors: CHAUDHARY SUNEAL K.
Published: November 2007

This paper describes a fast, flexible numerical technique to price American options and generate their value surface through time. The method runs faster and more accurately than the standard CRR binomial method in practical cases and calculates options on a considerably broader family of new, useful underlying asset processes. The technique relies on the Fast Fourier Transform (FFT) to convolve a transition function for the underlying asset process. The method allows the underlying asset process to be quite general; the previously known standard geometric Brownian motion and the Variance Gamma process [8], and a novel, purely empirical transition function are compared by computing their respective American put value surface and the exercise boundaries.
A CONTINUOUS TIME APPROXIMATION OF AN EVOLUTIONARY STOCK MARKET MODEL
Authors: BUCHMANN BORIS , WEBER STEFAN
Published: November 2007

We derive a continuous time approximation of the evolutionary market selection model of Blume and Easley (1992). Conditions on the payoff structure of the assets are identified that guarantee convergence. We show that the continuous time approximation equals the solution of an integral equation in a random environment. For constant asset returns, the integral equation reduces to an autonomous ordinary differential equation. We analyze its long-run asymptotic behavior using techniques related to Lyapunov functions, and compare our results to the benchmark of profit-maximizing investors.
STRUCTURAL SIMILITUDE AND SCALING LAWS OF ANTI-SYMMETRIC CROSS-PLY LAMINATED CYLINDRICAL SHELLS FOR BUCKLING AND VIBRATION EXPERIMENTS
Authors: UNGBHAKORN VARIDDHI , WATTANASAKULPONG NUTTAWIT
Published: November 2007

Developed herein are the scaling laws for physical modeling of anti-symmetric cross-ply laminated circular cylindrical shells for buckling and free vibration experiments. In the absence of experimental data, the validity of the scaling laws is verified by numerical experiments. This is accomplished by calculating theoretically the buckling loads and fundamental frequencies of the model and substituting into the scaling laws to obtain the corresponding values of the prototype. The predicted values of the prototype from the scaling laws are then compared with existing closed-form solutions. Examples for the complete similitude cases with various stacking sequences, number of plies, and length-to-radius ratios show exact agreement. The derived relationships between the model and prototype will greatly facilitate and reduce the need for costly experiments. In reality, either due to the complexity of the scaling laws or to economize experimental cost and time, it may not be feasible to construct the model to fulfil the scaling laws completely. Thus, several possible models of partial similitude are investigated numerically. These include models with distortion in laminated material properties, stacking sequences and number of plies. Model with distortion in material properties yields a high percentage of discrepancy and is not recommended.
STABILITY EVALUATION OF STEEL CABLE-STAYED BRIDGES BY ELASTIC AND INELASTIC BUCKLING ANALYSES
Authors: CHOI DONG-HO , YOO HOON , KOH JUNG-HOON , NOGAMI KUNIEI
Published: November 2007

The purpose of this paper is to compare the design equation of Allowable Stress Design (ASD) with that of Load and Resistance Factor Design (LRFD) concerning the member stability for the economic design of cable-stayed bridges. Both elastic and inelastic buckling analyses are carried out for the cable-stayed bridges with the effective buckling lengths of the key members calculated. The axial-flexural interaction equations prescribed in ASD and LRFD are used to check the stability of main members in cable-stayed bridges. Parametric studies are performed for the bridges with a center span of 300, 600, 900, and 1200 m of different girder depths. Peak values of the interaction equations are calculated at the intersection between the girder and towers. Since the peak values of the interaction equations by inelastic buckling analysis are less than those by elastic buckling analysis, a more economical design of the girder and towers can be achieved using the inelastic buckling analysis. In addition, the use of LRFD specifications can result in a more economical design by about 20% on average than the ASD specifications for steel cable-stayed bridges.
PARAMETRIC IDENTIFICATION OF NONLINEAR DYNAMIC SYSTEMS USING COMBINED LEVENBERG–MARQUARDT AND GENETIC ALGORITHM
Authors: KISHORE KUMAR R. , SANDESH S. , SHANKAR K.
Published: November 2007

This technical note presents the parametric identification of multi-degree-of-freedom nonlinear dynamic systems in the time domain using a combination of Levenberg–Marquardt (LM) method and Genetic Algorithm (GA). Here the crucial initial values to the LM algorithm are supplied by GA with a small population size. Two nonlinear systems are studied, the complex one having two nonlinear spring-damper pairs. The springs have cubic nonlinearity (Duffing oscillator) and dampers have quadratic nonlinearity. The effects of noise in the acceleration measurements and sensitivity analysis are also studied. The performance of combined GA and LM method is compared with pure LM and pure GA in terms of solution time, accuracy and number of iterations, and convergence and great improvement is observed. This method is found to be suitable for the identification of complex nonlinear systems, where the repeated solution of the numerically difficult equations over many generations requires enormous computational effort.
LEVI–CIVITA CONNECTION ON ALMOST COMMUTATIVE ALGEBRAS
Authors: NGAKEU F.
Published: November 2007

Recently we introduced a new definition of metrics on almost commutative algebras. In this paper, we propose a coherent notion of compatible linear connection with respect to any almost commutative tensor and show that to every metric there corresponds a unique torsion-free compatible connection. This connection is called the Levi–Civita connection of the associated metric.
GEOMETRIC AND EXTENSOR ALGEBRAS AND THE DIFFERENTIAL GEOMETRY OF ARBITRARY MANIFOLDS
Authors: FERNÁNDEZ V. V. , MOYA A. M. , RODRIGUES W. A.
Published: November 2007

We give in this paper which is the third in a series of four a theory of covariant derivatives of representatives of multivector and extensor fields on an arbitrary open set U ⊂ M, based on the geometric and extensor calculus on an arbitrary smooth manifold M. This is done by introducing the notion of a connection extensor field γ defining a parallelism structure on U ⊂ M, which represents in a well-defined way the action on U of the restriction there of some given connection ∇ defined on M. Also we give a novel and intrinsic presentation (i.e. one that does not depend on a chosen orthonormal moving frame) of the torsion and curvature fields of Cartan's theory. Two kinds of Cartan's connection operator fields are identified, and both appear in the intrinsic Cartan's structure equations satisfied by the Cartan's torsion and curvature extensor fields. We introduce moreover a metrical extensor g in U corresponding to the restriction there of given metric tensor g defined on M and also introduce the concept of a geometric structure(U, γ ,g) for U ⊂ M and study metric compatibility of covariant derivatives induced by the connection extensor γ. This permits the presentation of the concept of gauge (deformed) derivatives which satisfy noticeable properties useful in differential geometry and geometrical theories of the gravitational field. Several derivatives of operators in metric and geometrical structures, like ordinary and covariant Hodge co-derivatives and some duality identities are exhibited.
CLIFFORD AND EXTENSOR CALCULUS AND THE RIEMANN AND RICCI EXTENSOR FIELDS OF DEFORMED STRUCTURES (M, ∇′, η) AND (M, ∇, g)
Authors: FERNÁNDEZ V. V. , RODRIGUES W. A. , MOYA A. M. , DA ROCHA R.
Published: November 2007

Here (the last paper in a series of four) we end our presentation of the basics of a systematical approach to the differential geometry of a smooth manifold M (supporting a metric field g and a general connection ∇) which uses the geometric algebras of multivector and extensors (fields) developed in previous papers. The theory of the Riemann and Ricci fields of a triple (M, ∇, g) is investigated for each particular open set U ⊂ M through the introduction of a geometric structure on U, i.e. a triple (U, γ, g), where γ is a general connection field on U and g is a metric extensor field associated to g. The relation between geometrical structures related to gauge extensor fields is clarified. These geometries may be said to be deformations one of each other. Moreover, we study the important case of a class of deformed Levi–Civita geometrical structures and prove key theorems about them that are important in the formulation of geometric theories of the gravitational field.
QUADRATIC AND HOMOGENEOUS HAMILTON–POISSON SYSTEM ON (so(3))
Authors: ARON ANANIA , DĂNIASĂ CORA , PUTA MIRCEA
Published: November 2007

We study some geometrical and dynamical properties of a quadratic and homogeneous Hamilton–Poisson system defined on the dual of the Lie algebra so(3) with its minus-Lie-Poisson structure.
A NEW ALGEBRAIC STRUCTURE OF FINITE QUANTUM SYSTEMS AND THE MODIFIED BESSEL FUNCTIONS
Authors: FUJII KAZUYUKI
Published: November 2007

In this paper we present a new algebraic structure (a superhyperbolic system in our terminology) for finite quantum systems, which is a generalization of the usual one in the two-level system.

It fits into the so-called generalized Pauli matrices, so they play an important role in theory. Some deep relation to the modified Bessel functions of integer order is pointed out.

By taking a skillful limit finite quantum systems become quantum mechanics on the circle developed by Ohnuki and Kitakado.
Recent Declines in Chronic Disability in the Elderly U.S. Population: Risk Factors and Future Dynamics
Authors: Manton Kenneth G.
Published: November 2007

As U.S. life expectancy has increased, questions arise as to how the quality of health and functioning in the elderly population has changed. Data from the 1982–2004 National Long-Term Care Survey (NLTCS) suggested that chronic disability prevalence above age 65 declined at an increasing rate with a 2.2% per annum rate of decline from 1999 to 2004 ( 71 ). Inflation-adjusted per capita Medicare expenditure rates in nondisabled persons also declined, 0.9% per annum from 1982 to 2004, which suggests that declines in disability were driven by improving health—not by increases in per capita health expenditures. Declines in disability prevalence were found in other U.S. national health surveys. Analyses of U.S. Civil War veterans suggest recent disability declines were continuations of declines in both chronic disease and disability occurring over the past century due to improved nutrition, sanitation, and education. Concerns exist about whether disability declines will continue because of recent increases in obesity prevalence.
NF-κB-dependent transcriptional regulation of the cardiac scn5a sodium channel by angiotensin II
Authors: Shang Lijuan L. , Sanyal Shamarendra , Pfahnl Arnold E. , Jiao Zhe , Allen Jon , Liu Hong , Dudley Samuel C.
Published: November 2007

Angiotensin II (ANG II) increases oxidative stress and is associated with increased risk of sudden cardiac death. The cardiac Na+ channel promoter contains elements that confer redox sensitivity. We tested the hypothesis that ANG II-mediated oxidative stress may modulate Na+ channel current through altering channel transcription. In H9c2 myocytes treated for 48 h with ANG II (100 nmol/l) or H2O2 (10 μmol/l) showed delayed macroscopic inactivation, increased late current, and 59.6% and 53.8% reductions in Na+ current, respectively ( P ≤ 0.01). By quantitative real-time RT-PCR, the cardiac Na+ channel (scn5a) mRNA abundance declined by 47.3% ( P < 0.01) in H9c2 myocytes treated for 48 h with 100 nmol/l ANG II. A similar change occurred with 20 μmol/l H2O2 (46.9%, P < 0.01) after 48 h. Comparable effects were seen in acutely isolated ventricular myocytes. The effects of ANG II could be inhibited by prior treatment of H9c2 cells with scavengers of reactive oxygen species or an inhibitor of the NADPH oxidase. Mutation of the scn5a promoter NF-κB binding site prevented decreased activity in response to ANG II and H2O2. Gel shift and chromosomal immunoprecipitation assays confirmed that nuclear factor (NF)-κB bound to the scn5a promoter in response to ANG II and H2O2. Overexpression of the p50 subunit of NF-κB in H9c2 cells reduced scn5a mRNA (77.3%, P < 0.01). In conclusion, ANG II can decrease scn5a transcription and current. This effect appears to be through production of H2O2 resulting in NF-κB binding to the Na+ channel promoter.
Diet-induced obesity and hepatic steatosis inL-Fabp−/−mice is abrogated with SF, but not PUFA, feeding and attenuated after cholesterol supplementation
Authors: Newberry Elizabeth P. , Kennedy Susan M. , Xie Yan , Sternard Britni T. , Luo Jianyang , Davidson Nicholas O.
Published: November 2007

Liver fatty acid (FA)-binding protein (L-Fabp), a cytoplasmic protein expressed in liver and small intestine, regulates FA trafficking in vitro and plays an important role in diet-induced obesity. We observed that L-Fabp−/−mice are protected against Western diet-induced obesity and hepatic steatosis. These findings are in conflict, however, with another report of exaggerated obesity and increased hepatic steatosis in female L-Fabp−/−mice fed a cholesterol-supplemented diet. To resolve this apparent paradox, we fed female L-Fabp−/−mice two different cholesterol-supplemented low-fat diets and discovered (on both diets) lower body weight in L-Fabp−/−mice than in congenic wild-type C57BL/6J controls and similar or reduced hepatic triglyceride content. We extended these comparisons to mice fed low-cholesterol, high-fat diets. Female L-Fabp−/−mice fed a high-saturated fat (SF) diet were dramatically protected against obesity and hepatic steatosis, whereas weight gain and hepatic lipid content were indistinguishable between mice fed a high-polyunsaturated FA (PUFA) diet and control mice. These findings demonstrate that L-Fabp functions as a metabolic sensor with a distinct hierarchy of FA sensitivity. We further conclude that cholesterol supplementation does not induce an obesity phenotype in L-Fabp−/−mice, nor does it play a significant role in the protection against Western diet-induced obesity in this background.
Analysis ofl-NAME-dependent and -resistant responses to acetylcholine in the rat
Authors: Dabisch Paul A. , Liles John T. , Baber Syed R. , Golwala Neel H. , Murthy S. N. , Kadowitz Philip J.
Published: November 2007

The mechanism by which acetylcholine (ACh) decreases systemic arterial pressure and hindlimb vascular resistance was investigated in the anesthetized rat. ACh injections caused dose-dependent decreases in systemic arterial pressure and hindlimb vascular resistance. Nω-nitro-l-arginine methyl ester (l-NAME) had little effect on the magnitude of depressor and vasodilator responses but decreased response duration when baseline parameters were corrected by a nitric oxide (NO) donor infusion. The decrease in the duration of the ACh depressor response was prevented by the administration of excess l-arginine. The l-NAME-resistant component of the depressor response to ACh was attenuated by ebselen, a glutathione peroxidase mimic. The calcium-activated potassium (KCa) antagonists charybdotoxin (ChTX) and apamin decreased the magnitude but not the duration of the hindlimb vasodilator response to ACh. The combination of l-NAME, ChTX, and apamin reduced the magnitude and duration of the vasodilator response to ACh but not to sodium nitroprusside. Vasodepressor and hindlimb vasodilator responses to ACh were not modified by cytochrome P-450 and cyclooxygenase pathway inhibitors. These results suggest that the hindlimb vasodilator response to ACh has an initial l-NAME-resistant component mediated by the activation of KCachannels and a sustained l-NAME-dependent component. The results with ebselen suggest that the l-NAME-resistant component of the depressor response involves a peroxide-sensitive mechanism. The present study suggests that vasodilator responses to ACh are not mediated by cytochrome P-450 products, since miconazole and 1-aminobentriazole alone or in combination did not affect either component of the response. The present data suggest that the hindlimb vasodilator response to ACh in the rat is mediated by two mechanisms with an initial ChTX- and apamin-sensitive, l-NAME-resistant phase not mediated by cytochrome P-450 products and a secondary sustained phase mediated by NO.