bluuebunny/crossref_metadata_2025 huggingface dataset:
Responses to shading in Chenopodium album: the effect of the maternal environment and the N source supplied
Authors: Causin Humberto F
Published: October 2004

To study the effect of the maternal environment and N sources in responses to shading in Chenopodium album L., seeds from plants grown at an ambient red/far red (R/FR) ratio (1.07) or a low R/FR ratio (0.39) were germinated in a greenhouse at ambient light. At 34 d after sowing (d.a.s.), they were exposed to either ambient R/FR (0.98) or low R/FR (0.21) progeny light treatments and fertilized with 2.7 mmol/L nitrogen supplied at 1:3 or 3:1 NO3 : NH4+ ratios. Two harvests were performed at 67 and 113 d.a.s. At each harvest, stem elongation traits and biomass of plant organs were recorded. In the first harvest, tissue N% and free NO3-N concentrations were analyzed. In the first harvest, plants from the low R/FR maternal treatment were heavier and taller than the maternal controls when grown at an ambient R/FR and with a high NO3 supply. At the second harvest this difference persisted in most of the conditions tested. Stem elongation and relative biomass allocation to the stem increased in the low R/FR treated plants, although the effect varied during ontogeny and with the maternal and nutrient treatment considered. The studied factors also affected N acquisition and metabolism. It is concluded that responses to the light spectral quality as well as plant N economy are influenced by the R/FR ratio of the maternal environment and that their expression may be altered by the relative availability of NO3-N and NH4+-N.Key words: ammonium, Chenopodium album, light spectral quality, maternal effects, nitrate, shade-avoidance responses.
Magnetic and gravity models across terrane boundaries in southern New Brunswick, Canada
Authors: King M S , Barr S M
Published: October 2004

Regional magnetic and gravity map patterns, combined with modeling of magnetic and gravity data constrained by measured magnetic susceptibility and density information, are used to develop a better understanding of the three-dimensional character of major lithostratigraphic subdivisions (terranes) in southern New Brunswick. Models and long wavelength map patterns indicate that the boundaries between the Caledonia, Brookville, Kingston, and New River terranes are sub-vertical or dip slightly to the southeast, and that some map units in each terrane extend to depths ranging from 50008000 m. The Mascarene and St. Croix terranes are less well constrained than the more outboard terranes on the models, in part because of limited physical property data but also because of the presence of the Saint George Batholith, which obscures relationships among stratigraphic units. The models are consistent with the Mascarene terrane being a cover sequence over the boundary between the St. Croix and New River terranes, the specific location and nature of which is now revealed by the geophysical models. The terranes appear to be associated at depth with geophysically distinct bodies that are interpreted to correspond to the basements, from southeast to northwest, of Avalon terrane sensu stricto, BrookvilleBras d'Or terrane, and ExploitsGander composite terrane. The latter "Gander basement" underlies the Kingston, New River, Mascarene, and St. Croix terranes.
Age constraints on the Paleoproterozoic tectonometamorphic history of the Committee Bay region, western Churchill Province, Canada: evidence from zircon and in situ monazite SHRIMP geochronology
Authors: Carson Chris J , Berman Robert G , Stern Richard A , Sanborn-Barrie Mary , Skulski Tom , Sandeman Hamish AI
Published: October 2004

In situ UPb sensitive high-resolution ion microprobe (SHRIMP) analyses of monazite from upper amphibolite-facies paragneiss of the Committee Bay supracrustal belt, central Rae domain, Canada, reveal three age populations: ca. 2350, 1850, and 1780 Ma. The ca. 1850 Ma age also corresponds to growth of low Th/U zircon as indicated by UPb SHRIMP analyses of zircon separates from melanosome and leucosome. The contextual advantage of the in situ monazite analysis allows evaluation of the geochronological data in terms of the regional structural and metamorphic evolution. The region is dominated by a northeast-striking S2 (±S1) fabric, axial planar to tight, northwest-vergent F2 folds. Early garnet is enveloped by this biotitesillimanite ± cordierite S2 fabric. GarnetI hosts ca. 1850 Ma monazite inclusions (with ca. 2350 Ma cores), placing a maximum age on garnetI growth and S2 development. D2 metamorphic conditions progressed through ~3.5 kbar (1 kbar = 100 MPa) and 600 °C to near-peak conditions of ~5 kbar and 675 °C. A minimum age for S2 is provided by unstrained ca. 1820 Ma monzogranite that locally, and regionally, truncates S2. Dominantly ca. 1780 Ma matrix monazite is interpreted to date post-S2 garnetII and cordierite, which record ~5 kbar and 675 °C. These data indicate that the Committee Bay region experienced penetrative D2 tectonometamorphism at ca. 18501820 Ma, with a subsequent static overprint. The absence of a ca. 1.85 Ga plutonic suite in the region suggests that low-pressure metamorphism was a response to thick-skinned crustal thickening initiated at ca. 1870 Ma. The new data highlight the importance of Paleoproterozoic reworking of the central Rae domain in the hinterland of the Trans-Hudson orogen.
A comparative SEM study on the micromorphology of glacial and nonglacial clasts with varying age and lithology
Authors: Van Hoesen John G , Orndorff Richard L
Published: October 2004

Preliminary research on striated clasts from a variety of depositional environments suggests that scanning electron microscopy (SEM) of striated clasts of varying lithology in diamictons may prove useful in interpreting a glacial origin. Evaluating whether SEM analysis of clasts from diamictons is an applicable technique to define a glacial origin requires a better understanding of the microfeatures occurring on glacial and nonglacial clasts. We describe microtextures and surface characteristics for samples of quartzite, granite, limestone, basalt, chert, pillow basalt, and quartz pebbles collected from a variety of depositional environments. Our study suggests that it is possible to differentiate between glacial and nonglacial deposits based on frequency and morphology of diagnostic surface microfeatures observed on entrained clasts. These microfeatures are best preserved and identified on competent and monomineralic samples (e.g., quartzite, chert, limestone) and poorly preserved on less resistant and polymineralic samples (e.g., basalt and granite).
High-resolution mapping of theSandZloci ofPhalaris coerulescens
Authors: Bian X -Y , Friedrich A , Bai J -R , Baumann U , Hayman D L , Barker S J , Langridge P
Published: October 2004

Self incompatibility (SI) in Phalaris coerulescens is gametophytically determined by two unlinked multi allelic loci (S and Z). Neither the S nor Z genes have yet been cloned. As part of a map-based cloning strategy, high-resolution maps of the S and Z regions were generated from distorted segregating populations using RFLP probes from wheat, barley, oat, and Phalaris. The S locus was delimited to 0.26 cM with two boundary markers (Xwg811 and Xpsr168) and cosegregated with Xbm2 and Xbcd762. Xbcd266 was the closest marker linked to Z (0.9 cM). A high level of colinearity in the S and Z regions was found in both self-incompatible and -compatible species. The S locus was localized to the subcentromere region of chromosome 1 and the Z locus to the long arm end of chromosome 2. Several rice BAC clones orthologous to the S and Z locus regions were identified. This opens the possibility of using the rice genome sequence data to generate more closely linked markers and identify SI candidate genes. These results add further support to the conservation of gene order in the S and Z regions of the grass genomes.Key words: Phalaris coerulescens, self-incompatibility, distorted segregation, mapping, map-based cloning, synteny mapping.
Microsatellite markers provide evidence for sexual reproduction ofMycosphaerella graminicolain Saskatchewan
Authors: Razavi M , Hughes G R
Published: October 2004

This study examined the genetic structure of a Saskatchewan population of Mycosphaerella graminicola, cause of the foliar disease Septoria tritici blotch of wheat. Such knowledge is valuable for understanding the evolutionary potential of this pathogen and for developing control strategies based on host resistance. Nine pairs of single-locus microsatellite primers were used to analyze the genomic DNA of 90 isolates of M. graminicola that were collected using a hierarchical sampling procedure from different locations, leaves, and lesions within a wheat field near Saskatoon. Allelic series at eight different loci were detected. The number of alleles per locus ranged from one to five with an average of three alleles per locus. Genetic diversity values ranged from 0.04 to 0.67. Partitioning the total genetic variability into within- and among-location components revealed that 88% of the genetic variability occurred within locations, i.e., within areas of 1 m2, but relatively little variability occurred among locations. Low variability among locations and a high degree of variability within locations would result if the primary source of inoculum was airborne ascospores, which would be dispersed uniformly within the field. This finding was confirmed by gametic disequilibrium analysis and suggests that the sexual reproduction of M. graminicola occurs in Saskatchewan.Key words: Mycosphaerella graminicola, SSR markers, sexual reproduction, genetic diversity.
The prevalence and evolution of sex in microorganisms
Authors: Xu Jianping
Published: October 2004

The origin of sex and how sex is maintained are among the biggest puzzles in biology. Most investigations into this problem have focused on complex eukaryotes like animals and plants. This mini-review summarizes recent progress in our understanding of the evolution of sex, highlighting results from studies of experimental and natural populations of microorganisms. Increasing evidence indicates that sexual reproduction in natural populations of viruses, bacteria, and eukaryotic microbes is much more prevalent than previously thought. In addition, investigations using experimental microbial populations are providing important parameters relevant to our understanding of the origin and maintenance of sex. It is argued that microbes are excellent model organisms to explore the mechanisms responsible for the evolution of sex.Key words: costs and benefits of sex, natural populations, experimental populations, Müller's Ratchet, interaction among mutations, loss of sex.
Genomic in situ hybridization in plants with small genomes is feasible and elucidates the chromosomal parentage in interspecific Arabidopsis hybrids
Authors: Ali Hoda B.M , Lysak Martin A , Schubert Ingo
Published: October 2004

Genomic in situ hybridization (GISH) is a useful tool to analyse natural polyploids, hybrid plants, and their backcross progenies as to their origin, genomic composition, and intergenomic rearrangements. However, in angiosperms with very small genomes (<0.6 pg/1 C), often only heterochromatic regions were found to be labeled. We have modified the GISH technique to label entire mitotic and meiotic chromosomes of Arabidopsis thaliana (2n = 10) and closely related species with very small genomes by using high concentrations of DNA (7.5–15 µg per probe per slide) or 5 µg of probe and long hybridization times (>60 h). According to our GISH data, Cardaminopsis carpatica (2n = 16) is most likely the diploid ancestor of the autotetraploid Arabidopsis arenosa (2n = 32). Furthermore, within the allotetraploid species Arabidopsis suecica (2n = 26), it was possible to elucidate the origin of chromosomes contributed by the parental species A. thaliana and A. arenosa for a specimen with 2n = 26 or a deviating chromosome number.Key words: genomic in situ hybridization (GISH), Arabidopsis, Brassicaceae, allopolyploids, synthetic hybrids.
Features of a 103-kb gene-rich region in soybean include an inverted perfect repeat cluster ofCHSgenes comprising theIlocus
Authors: Clough Steven J , Tuteja Jigyasa H , Li Min , Marek Laura F , Shoemaker Randy C , Vodkin Lila O
Published: October 2004

The I locus in soybean (Glycine max) corresponds to a region of chalcone synthase (CHS) gene duplications affecting seed pigmentation. We sequenced and annotated BAC clone 104J7, which harbors a dominant iiallele from Glycine max 'Williams 82', to gain insight into the genetic structure of this multigenic region in addition to examining its flanking regions. The 103-kb BAC encompasses a gene-rich region with 11 putatively expressed genes. In addition to six copies of CHS, these genes include: a geranylgeranyltransferase type II β subunit (E.C.2.5.1.60), a β-galactosidase, a putative spermine and (or) spermidine synthase (E.C.2.5.1.16), and an unknown expressed gene. Strikingly, sequencing data revealed that the 10.91-kb CHS1, CHS3, CHS4 cluster is present as a perfect inverted repeat separated by 5.87 kb. Contiguous arrangement of CHS paralogs could lead to folding into multiple secondary structures, hypothesized to induce deletions that have previously been shown to effect CHS expression. BAC104J7 also contains several gene fragments representing a cation/hydrogen exchanger, a 40S ribosomal protein, a CBL-interacting protein kinase, and the amino terminus of a subtilisin. Chimeric ESTs were identified that may represent read-through transcription from a flanking truncated gene into a CHS cluster, generating aberrant CHS RNA molecules that could play a role in CHS gene silencing.Key words: chalcone synthase, gene duplication, gene silencing, gene-rich region, soybean, BAC.
A genome-wide analysis of courting and mating responses inDrosophila melanogasterfemales
Authors: Lawniczak Mara KN , Begun David J
Published: October 2004

In Drosophila melanogaster, seminal fluid proteins influence several components of female physiology and behavior, including re-mating rates, ovulation and oviposition, and sperm use. It is well-known that female flies are not simply passive vessels and that female-mediated interactions with male products are important to female (and thus male) reproductive success. While the population genetics, molecular evolution and physiological effects of seminal fluid proteins have been examined, the genetics and evolution of the female side of these post-mating interactions is unexplored in spite of work showing that female genotype and female-by-male genotype interactions are important determinants of sperm competition outcomes. Here we use microarrays to identify candidate genes involved in the female side of post-mating sexual interactions. We report the results of a whole-genome oligonucleotide chip experiment that reveals 23 genes differentially expressed between virgin females exposed and unexposed to courting males, and 38 genes differentially expressed between virgin and recently mated females. Immune related genes are overrepresented among the mating-influenced candidates. We use quantitative reverse-transcriptase PCR to independently assess gene expression changes for roughly half of the mating-affected candidate genes.Key words: reproduction, gene expression, Drosophila immune related genes, serine proteases, accessory gland proteins.
Polyploidization-induced genome variation in triticale
Authors: Ma Xue-Feng , Fang Peng , Gustafson J Perry
Published: October 2004

Polyploidization-induced genome variation in triticale (× Triticosecale Wittmack) was investigated using both AFLP and RFLP analyses. The AFLP analyses were implemented with both EcoRI–MseI (E–M) and PstI–MseI (P–M) primer combinations, which, because of their relative differences in sensitivity to cytosine methylation, primarily amplify repetitive and low-copy sequences, respectively. The results showed that the genomic sequences in triticale involved a great degree of variation including both repetitive and low-copy sequences. The frequency of losing parental bands was much higher than the frequency of gaining novel bands, suggesting that sequence elimination might be a major force causing genome variation in triticale. In all cases, variation in E–M primer-amplified parental bands was more frequent in triticale than that using P–M primers, suggesting that repetitive sequences were more involved in variation than low-copy sequences. The data also showed that the wheat (Triticum spp.) genomes were relatively highly conserved in triticales, especially in octoploid triticales, whereas the rye (Secale cereale L.) genome consistently demonstrated a very high level of genomic sequence variation (68%–72%) regardless of the triticale ploidy levels or primers used. In addition, when a parental AFLP band was present in both wheat and rye, the tendency of the AFLP band to be present in triticale was much higher than when it was present in only one of the progenitors. Furthermore, the cDNA-probed RFLP analyses showed that over 97% of the wheat coding sequences were maintained in triticale, whereas only about 61.6% of the rye coding sequences were maintained, suggesting that the rye genome variation in triticale also involved a high degree of rye coding sequence changes. The data also suggested that concerted evolution might occur in the genomic sequences of triticale. In addition, the observed genome variation in wheat–rye addition lines was similar to that in triticale, suggesting that wheat–rye addition lines can be used to thoroughly study the genome evolution of polyploid triticale.Key words: wheat, rye, polyploid, genome evolution, sequence elimination.
Development of a unique deterioration index, prioritization methodology, and foreign object damage evaluation models for Canadian airfield pavement management
Authors: Shah Anwar , Tighe Susan , Stewart Allen
Published: October 2004

Modelling of pavement performance deterioration is a critical engineering process in Pavement Management Systems. Most of the existing Airport Pavement Management Systems (APMS) employ limited surface distresses in their performance evaluation models. These systems may not serve the objectives of some agencies. It is essential for an effective APMS to include evaluation models that adequately address the specific needs of the agency. This paper presents the development of a unique pavement deterioration index, i.e., the Condition Rating Index, developed for 1 Canadian Air Division (1 CAD). This index is modelled to serve the specific needs of 1 CAD effectively. Performance prediction models for the various classes of pavements are developed based on Markov Chains. The prioritization methodology employed also reflects the needs of 1 CAD. Consequently, this paper investigates the quantification and prediction of Foreign Object Damage (FODp). The FODp Index is developed as well as defined. Prediction models for FODp are developed along with the establishment of critical states of the FODp Index.Key words: airport pavement management system, Condition Rating Index, pavement performance evaluation models, Foreign Object Damage, 1 Canadian Air Division.
Introduction to the use of wavelet multiresolution analysis for intelligent structural health monitoring
Authors: Taha M.M Reda , Noureldin A , Osman A , El-Sheimy N
Published: October 2004

This paper suggests the use of wavelet multiresolution analysis (WMRA) as a reliable tool for digital signal processing in structural health monitoring (SHM) systems. A damage occurrence detection algorithm using WMRA augmented with artificial neural networks (ANN) is described. The suggested algorithm allows intelligent monitoring of structures in real time. The probability of damage occurrence is determined by evaluating the wavelet norm index (WNI) representing the energy of a signal describing the change in the system dynamics due to damage. An example application of the proposed algorithm is presented using a finite element simulated structural dynamics of a prestressed concrete bridge. The new algorithm showed very promising results.Key words: structural health monitoring, neural networks, wavelet analysis, signal processing, damage detection.
A simple formula for estimating backwater at bridge constrictions
Authors: Seckin Galip
Published: October 2004

The past experimental studies to investigate the backwater effects due to bridge constrictions have been mostly performed in setups of single rectangular channels with fairly smooth surfaces. Therefore, there is a need to investigate more realistic cross-sectional shapes and roughness conditions. The most obvious case is to consider bridges in natural channels with floodplains. This paper reports the findings of model testing of arch and straight deck bridge constrictions in a compound channel flume with both smooth and roughened surfaces. Four different types of bridge models, namely single opening semicircular, multiple opening semicircular, single opening elliptic, and straight deck models with and without piers, were used in the testing program. An attempt was made to develop a simple formula for estimating bridge backwater as a function of Froude number and opening ratio.Key words: bridge backwater, hydraulic model testing, open channel flow, flood control.
Conceptual cost estimation of building projects with regression analysis and neural networks
Authors: Sonmez Rifat
Published: October 2004

Conceptual cost estimates play a crucial role in initial project decisions, although scope is not finalized and very limited design information is available during early project stages. In this paper, the advantages and disadvantages of the current conceptual cost estimation methods are discussed and the use of regression, neural network, and range estimation techniques for conceptual cost estimation of building projects are presented. Historical cost data of continuing care retirement community projects were compiled to develop regression and neural network models. Three linear regression models were considered to identify the significant variables affecting project cost. Two neural network models were developed to examine the possible need for nonlinear or interaction terms in the regression model. Prediction intervals were constructed for the regression model to quantify the level of uncertainty for the estimates. Advantages of simultaneous use of regression analysis, neural networks, and range estimation for conceptual cost estimating are discussed.Key words: conceptual cost estimation, regression analysis, neural networks, range estimation.
Shake table testing of bookcase – partition wall systems
Authors: Filiatrault Andre , Kuan Steven , Tremblay Robert
Published: October 2004

This paper describes the seismic (shake table) tests conducted on bookcase – partition wall systems. These nonstructural building components can be considered acceleration sensitive (or motion sensitive) rather than drift sensitive. The shake table floor motions used for the seismic testing are described in a companion paper. One bookcase fully loaded with books and two different cantilevered partition wall systems were considered in the shake table tests. Nine different configurations of these free-standing nonstructural building components were tested. For each configuration, three different seismic hazard levels were considered for the motions at the second floor level of a six-storey building designed for two different densely populated Canadian cities (Montréal and Vancouver). A total of 485 shake table tests were conducted in this experimental investigation. The experimental results indicated that pounding between unanchored bookcases and partition walls is very beneficial to the dynamic response of the bookcases, as it prevents resonance from occurring. Also, the seismic performance of bookcases improved dramatically by the proper installation of seismic restraint systems. Experimental fragility curves for overturning of tall bookcases are presented.Key words: bookcases, earthquakes, fragility, interior partition walls, nonstructural, operational and functional components, pounding, seismic restraints, shake table.
Structural design of asphalt pavement on concrete bridges
Authors: Castro María
Published: October 2004

Traditional methods for the structural design of pavement cannot be applied to the design of pavement on bridge decks. In this paper, a new method for the structural design of asphalt pavement on concrete bridge decks is presented. The method can be applied to pavement on girder, slab, and box-girder bridges and can be used whatever the considered degree of bonding between pavement and deck. The method consists of modelling the deck as a two-layer system and then calculating stresses and strains in the pavement–deck system by means of a multilayer system. The proposed methodology has been applied to study the behaviour of asphalt concretes, porous asphalts, and stone matrix asphalts on girder, slab, and box-girder bridges. There is a conclusion of this application that stands out for its practical character. The stone matrix asphalts have the best performance if fatigue is the main concern.Key words: bridge decks, asphalt pavement, design.
Characterization of tire impact on the pavement behaviour
Authors: Pascale Pierre , Doré Guy , Prophète Fritz
Published: October 2004

The paper presents research conducted following an investigation carried out by the Quebec Ministry of Transportation's Roadwork Service on the effects of tire width. The study looked at the impact of tires on the surface layer of pavement and the pavement behaviour as a result of this impact. The strains at a depth of 25 mm in the pavement, at the base of the pavement, and at the top of the subgrade were measured. Measurements were taken over two seasons representative of conditions prevailing in Quebec, in spring and in summer. Three parameters, the type of tire, the inflation pressure of the tire, and finally the load, were varied. The amplitude of damage produced by the circulation of a vehicle was then quantified to evaluate and compare the overall impact of various types of tires on pavement according to the various configurations.Key words: pavement, surface layer, tire, interface, strain.
Modelling failures in existing reinforced concrete columns
Authors: Elwood Kenneth J
Published: October 2004

Experimental research and post-earthquake reconnaissance have demonstrated that reinforced concrete columns with light or widely spaced transverse reinforcement are vulnerable to shear failure, and in turn, axial failure during earthquakes. Based on experimental data, failure surfaces have been used to define the onset of shear and axial failure for such columns. After the response of the column intersects the failure surface, the shear or axial strength of the column begins to degrade. This paper introduces a uniaxial material model that incorporates the failure surfaces and the subsequent strength degradation. When used in series with a beam-column element, the uniaxial material model can adequately capture the response of reinforced concrete columns during shear and axial load failure. The performance of the analytical model is compared with results from shake table tests.Key words: shear failure, axial failure, beam-column elements, failure surface, earthquakes, reinforced concrete, columns, collapse, structural analysis.
Thermal design criteria for deep prestressed concrete girders based on data from Confederation Bridge
Authors: Li Dongning , Maes Marc A , Dilger Walter H
Published: October 2004

The evaluation of temperature data recorded on the world's longest bridge built over ice-covered water is presented. The data in question are the hourly recorded temperatures in three girder sections with variable geometry and ambient temperature, solar radiation, and wind speed measured on site from 1998 to 2000. The data were first carefully screened, and problematic records were identified and repaired. The temperatures were then spatially reduced to a set of thermal variables including average, differential, and residual temperatures. Extreme value analysis was performed to obtain 100 year return thermal loads. The results are compared with the provisions in the Canadian highway bridge design code (CAN/CSA-S6-00) and the original design temperatures for the bridge. Temperature distributions for maximum positive vertical differential temperatures during the recording period are plotted for the three girder sections. The observed unrestrained curvatures and nonlinear stresses are compared with those estimated by the Priestley model. Modifications are found to be necessary for extremely deep cross sections.Key words: concrete bridge, thermal response, statistical evaluation, average temperature, differential temperature, curvature, stress.
Electrodeposition as a rehabilitation method for concrete materials
Authors: Ryou J S , Monteiro P
Published: October 2004

Electrodeposition was used to rehabilitate cracked reinforced concrete both in the laboratory and under field conditions. First the chloride-induced specimens were cracked by applying a bending load, then the samples were immersed in a zinc sulfate solution, and a constant current was applied between the reinforcing steel and the external electrode. The results obtained in the laboratory showed that electrodeposition effectively repaired cracks in the concrete specimen; therefore, field investigations were performed on a 35-year old structure that had been damaged by corrosion to assess the feasibility of using this technique in field conditions. The field results indicate that the electro deposits formed on the concrete surface closed the cracks in the concrete. In addition, the application of electro deposition had beneficial effects on the electrochemical property of the reinforcing steel in concrete.Key words: electrodeposition, constant current, reinforcing steel, electrode, cracks, electrochemical property.
Fibre reinforced polymer composite bars for the structural concrete slabs of a Public Works and Government Services Canada parking garage
Authors: Benmokrane Brahim , El-Salakawy Ehab , Cherrak Zoubir , Wiseman Allan
Published: October 2004

Public Works and Government Services Canada (PWGSC) is currently undertaking the reconstruction of the interior structural slabs of the Laurier-Taché parking garage (Hull, Quebec). An agreement between PWGSC and the Université de Sherbrooke was reached to use fibre reinforced polymer (FRP) reinforcement technology in some demonstration areas of the Laurier–Taché parking garage. Based on this agreement, three different designs using carbon and glass FRP bars were carried out in collaboration with the project consultant. These designs were made according to CAN/CSA-S806-02, Design and Construction of Building Components with Fibre-Reinforced-Polymers. To verify the design, it was agreed to conduct laboratory testing on full-scale slab prototypes of the proposed designs. This paper presents the results of the experimental tests where six full-sized one-way slabs were constructed and tested. The slabs were 3100 mm long × 1000 mm wide × 150 mm deep and were tested under four-point bending. The test results along with a comparison to the predictions of CAN/CSA-S806-02 Code and ACI 440.1R-03 design guidelines are presented. Recommendations for design of FRP-reinforced concrete slabs are also given.Key words: concrete slabs, parking garages, FRP bars, flexural behaviour, cracking, deflection.
Evaluation of the expansion attained to date by concrete affected by alkali–silica reaction. Part I: Experimental study
Authors: Smaoui Nizar , Bérubé Marc-André , Fournier Benoit , Bissonnette Benoit , Durand Benoit
Published: October 2004

The expansion to date of the concrete from a structure affected by alkali–silica reaction (ASR) is a crucial parameter in the evaluation of the structural integrity of the structure. Three methods have been used to evaluate this expansion: (i) the "stiffness damage test" (SDT), (ii) the "damage rating index" (DRI), and (iii) surface cracking. Concrete cylinders were made using several types of coarse and fine reactive aggregates and subjected to the Canadian Standards Association (CSA) concrete prism test CSA A23.2-14A (or American Society for Testing and Materials (ASTM) test method C1293), i.e., at 38 °C and >95% relative humidity (RH). At various expansion levels, the specimens were subjected to SDT and DRI tests. Very good relationships were obtained between the expansion due to ASR and the SDT. The correlation between the ASR expansion and the DRI was not as good but still of interest. Width measurements of surface cracks were also performed on a number of blocks made with different reactive aggregates and exposed in the laboratory at 38 °C and >95% RH. The expansion estimated from these measurements was much lower than that measured on the blocks.Key words: aggregates, alkali–silica reaction, concrete expansion, damage rating index, petrography, stiffness damage test, surface cracking.
Flow over a stepped chute with and without macro-roughness elements
Authors: Kökpinar Mehmet Ali
Published: October 2004

High-speed two-phase flows over a 30° stepped flume were experimentally investigated using macro-roughness elements. The roughness elements included combinations of steps and horizontal strips. Local values of air concentration, air bubble frequency, and mean chord lengths were measured by a fiber-optical instrumentation system in the air–water flow region. The range of unit discharge of water was varied from 0.06 to 0.20 m2/s. Three step configurations were studied: (i) without macro-roughness elements, (ii) with macro-roughness elements on each step, and (iii) with macro-roughness elements on each second step (AMR configuration). The results were compared in terms of onset flow conditions and internal air–water flow parameters such as local air concentration, mean air bubble chord length distribution, and air bubble frequency in the skimming flow regime. It was observed that the AMR configuration produced the maximum free-surface aeration among the other configurations. This alternative step geometry has potential for less cavitation damage than conventional step geometry because of the greater air entrainment.Key words: stepped chute, air-entrainment, air-water flow properties, macro-roughness elements, skimming flow.
Modélisation des erreurs pour le système de prévision PRÉVIS
Authors: Lefebvre Mario
Published: October 2004

This paper examines models for the errors in forecasts of river and (or) watershed flows produced by the PREVIS forecasting system, which is used by Alcan, among other companies. We analyzed the following statistical models: generalized Pareto, Laplace, and Gaussian distributions, depending on the flow value forecasted by PREVIS. These models enable us to quantify the precision of the forecasts produced by PREVIS, as well as the risk of seeing the flow exceed a certain critical threshold, given the forecasted flow.Key words: modeling, Laplace distribution, Pareto distribution, goodness-of-fit tests, critical threshold.
Identification of the linker histone H1 as a protein kinase Cε-binding protein in vascular smooth muscle
Authors: Zhao Mingcai , Sutherland Cindy , Wilson David P , Deng Jingti , MacDonald Justin A , Walsh Michael P
Published: October 2004

A variety of anchoring proteins target specific protein kinase C (PKC) isoenzymes to particular subcellular locations or multimeric signaling complexes, thereby achieving a high degree of substrate specificity by localizing the kinase in proximity to specific substrates. PKCε is widely expressed in smooth muscle tissues, but little is known about its targeting and substrate specificity. We have used a Far-Western (overlay) approach to identify PKCε-binding proteins in vascular smooth muscle of the rat aorta. Proteins of ~32 and 34 kDa in the Triton-insoluble fraction were found to bind PKCε in a phospholipid/diacylglycerol-dependent manner. Although of similar molecular weight to RACK-1, a known PKCε-binding protein, these proteins were separated from RACK-1 by SDS-PAGE and differential NaCl extraction and were not recognized by an antibody to RACK-1. The PKCε-binding proteins were further purified from the Triton-insoluble fraction and identified by de novo sequencing of selected tryptic peptides by tandem mass spectrometry as variants of the linker histone H1. Their identity was confirmed by Western blotting with anti-histone H1 and the demonstration that purified histone H1 binds PKCε in the presence of phospholipid and diacylglycerol but absence of Ca2+. The interaction of PKCε with histone H1 was specific since no interaction was observed with histones H2A, H2S or H3S. Bound PKCε phosphorylated histone H1 in a phospholipid/diacylglycerol-dependent but Ca2+-independent manner. Ca2+-dependent PKC was also shown to interact with histone H1 but not other histones. These results suggest that histone H1 is both an anchoring protein and a substrate for activated PKCε and other PKC isoenzymes and likely serves to localize activated PKCs that translocate to the nucleus in the vicinity of specific nuclear substrates including histone H1 itself. Since PKC isoenzymes have been implicated in regulation of gene expression, stable interaction with histone H1 may be an important step in this process.Key words: protein kinase C, histone H1, signaling complexes, smooth muscle.
The effect of TNF-α on glycosylation pathways in bovine synoviocytes
Authors: Yang Xiaojing , Lehotay Michael , Anastassiades Tassos , Harrison Mark , Brockhausen Inka
Published: October 2004

Synoviocytes are fibroblastic cells that line joint cavities. These cells synthesize numerous cell-surface and extracellular-matrix glycoproteins that are required for maintenance of the joint. Joint inflammation, such as occurs in arthritis, has been shown to have major effects on synoviocyte proliferation and on the biosynthesis of glycoproteins. The structures of the carbohydrate moieties of glycoproteins, however, and the enzymes involved in their synthesis have not yet been described for synoviocytes. Therefore, to characterize the cell-surface glycoconjugates, synoviocytes were isolated from bovine ankles, and the cells were grown in primary cultures. Lectin-binding assays were used to identify exposed N- and O-glycan carbohydrate determinants on synoviocytes, and specific enzyme assays were used to identify some of the glycosyltransferases involved in the synthesis of the glycan chains. A number of the enzymes that synthesize N- and O-linked oligosaccharides were found to be active in cell-free extracts of synoviocytes, including those that synthesize core-1-based O-glycans and the more complex bi-antennary N-glycans. To understand the molecular events underlying the inflammatory response in the synovium of arthritis patients, we examined the effect of the inflammatory cytokine tumour necrosis factor α (TNF-α) on synoviocytes and on glycosylation profiles. TNF-α treatment, which induces apoptosis in synoviocytes, was accompanied by changes in lectin-binding patterns, indicating alterations in the expression of cell-surface oligosaccharides. Concurrently, changes in specific enzyme activities were observed in treated cells. Two enzymes potentially important to the inflammatory process, core 2 β6-GlcNAc-transferase and β4-Gal-transferase, increased after TNF-α treatment. This is the first study of glycoprotein biosynthesis in synoviocytes, and it shows that synoviocytes have a characteristic glycosylation phenotype that is altered in the presence of inflammatory cytokines.Key words: synoviocytes, glycoprotein biosynthesis, cytokines, TNF-α, apoptosis.
Suppression of clonogenicity by mammalian Dnmt1 mediated by the PCNA-binding domain
Authors: Santourlidis Simeon , Kimura Fumihiro , Fischer Johannes , Schulz Wolfgang A
Published: October 2004

Overexpression of the major DNA methyltransferase Dnmt1 is cytotoxic and has been hypothesized to result in aberrant hypermethylation of genes required for cell survival. Indeed, overexpression of mouse or human Dnmt1 in murine and human cell lines decreased clonogenicity. By frame-shift and deletion constructs, this effect of mouse Dnmt1 was localized at the N-terminal 124 amino acid domain, which mediates interaction with proliferating cell nuclear antigen (PCNA). Mutation of the PCNA-binding site restored normal cloning efficiencies. Overexpression of Dnmt3A or Dnmt3B, which do not interact with PCNA, yielded weaker effects on clonogenicity. Following introduction of the toxic domain, no significant effects on apoptosis, replication, or overall DNA methylation were observed for up to 3 d. Suppression of clonogenicity by Dnmt1 was also observed in cell lines lacking wild-type p53, p21CIP1, or p16INK4A. Suppression of clonogenicity by Dnmt1 overexpression may act as a fail-safe mechanism against carcinogenicity of sustained Dnmt1 overexpression.Key words: carcinogenesis, DNA methyltransferase, DNA methylation, p53, PCNA.
Unsteady magnetohydrodynamic micropolar fluid flow and heat transfer over a vertical porous plate through a porous medium in the presence of thermal and mass diffusion with a constant heat source
Authors: Ibrahim F S , Hassanien I A , Bakr A A
Published: October 2004

In this work, the effects of a temperature-dependent heat source on the hydromagnetic free-convective flow (set up due to temperature as well as species concentration) of an electrically conducting micropolar fluid past a steady vertical porous plate through a highly porous medium has been analyzed when the free stream oscillates in magnitude. A uniform magnetic field acts perpendicularly to the porous surface, which absorbs the micropolar fluid with constant suction velocity. The method of solution can be applied for a small perturbation approximation. The numerical results of velocity and temperature distributions of micropolar fluids are compared with the corresponding flow problems for a Newtonian fluid. The effects of the material parameters on velocity, angular momentum, concentration, and temperature fields across the boundary layer are investigated. In addition, the skin-friction coefficient and Nusselt number are shown in tabular form.PACS Nos.: 44.05.+e, 44.30.+v, 47.11.+j, 47.27.Te, 47.55.Mh, 47.65.+a, 47.50.+d
Unified treatment of electronic attraction, electric field, and electric-field gradient multicenter integrals of reened and nonscreened Coulomb potentials using overlap integrals for Slater orbitals
Authors: Guseinov I I
Published: October 2004

A unified treatment of multicenter electronic attraction (EA), electric field (EF), and electric-field gradient (EFG) integrals of Yukawa-like screened and nonscreened Coulomb potentials with Slater-type orbitals (STOs) is described. Using different sets of series expansion formulas of two-center distributions for STOs in terms of STOs at a displaced center the EA, EF, and EFG integrals over STOs are expressed through the overlap integrals between potentials or their derivatives and STOs. These two-center overlap integrals are evaluated by the use of rotational transformation for overlap integrals established by the author. The final results expressed through the overlap integrals of STOs with the same screening constants are valid for the arbitrary parameters of STOs and potentials. PACS No.: 31.15.p
Multicharged Xei+ ions formed after de-excitation of inner-shell vacancies in Xe atom
Authors: El-Shemi Adel M
Published: October 2004

Multicharged Xe ions following de-excitation of K-, L1-, L2,3-, M1-, M2,3-, and M4,5-subshell vacancies are calculated using a Monte-Carlo algorithm to simulate the vacancy cascade development. Fluorescence yield (radiative) and Auger and CosterKronig yields (nonradiative) are evaluated. The decay of the K hole state through radiative transitions is found to be more probable than through nonradiative transitions in the first step of de-excitation. On the other hand, the decay of L and M vacancies through nonradiative transitions are more probable. Ions, mainly produced from Xe in the K-shell vacancy state, are found to be Xe7+, Xe8+, Xe9+, and Xe10+. The charged Xe8+ ions predominate in the charge state distributions. The main product from the L1-shell ionization is found to be Xe8+ and Xe9+ ions, while the Xe8+ ions predominate at the L2,3 hole states. The charged Xe6+, Xe7+, and Xe8+ ions come mainly from 3s1/2 and 3p1/2,3/2 ionization, while Xe in 3d3/2,5/2 hole states becomes mainly Xe4+ and Xe5+ ions. The present results are found to agree well with the experimental data.PACS No.: 32.40.Hd
Instant-form Hamiltonian and BecchiRouetStoraTyutin formulations of the NielsenOlesen model in the broken symmetry phase
Authors: Kulshreshtha Usha , Kulshreshtha D S
Published: October 2004

The usual instant-form (equal-time) Hamiltonian and BecchiRouetStoraTyutin formulations of the NielsenOlesen model are investigated in two-space one-time dimension in the broken (frozen) symmetry phase, where the phase ϕ(xμ) of the complex matter field Φ(xμ) carries the charge degree of freedom of the complex matter field and is, in fact, akin to the Goldstone boson. PACS No.: 11.10.Ef
Predicting the saturated hydraulic conductivity of sand and gravel using effective diameter and void ratio
Authors: Chapuis Robert P
Published: October 2004

This paper assesses methods to predict the saturated hydraulic conductivity, k, of clean sand and gravel. Currently, in engineering, the most widely used predictive methods are those of Hazen and the Naval Facilities Engineering Command (NAVFAC). This paper shows how the Hazen equation, which is valid only for loose packing when the porosity, n, is close to its maximum value, can be extended to any value of n the soil can take when its maximum value of n is known. The resulting extended Hazen equation is compared with the single equation that summarizes the NAVFAC chart. The predictive capacity of the two equations is assessed using published laboratory data for homogenized sand and gravel specimens, with an effective diameter d10between 0.13 and 1.98 mm and a void ratio e between 0.4 and 1.5. A new equation is proposed, based on a best fit equation in a graph of the logarithm of measured k versus the logarithm of d102e3/(1 + e). The distribution curves of the differences log(measured k)  log(predicted k) have mean values of 0.07, 0.21, and 0.00 for the extended Hazen, NAVFAC, and new equations, respectively, with standard deviations of 0.23, 0.36, and 0.10, respectively. Using the values of d10and e, the new equation predicts a k value usually between 0.5 and 2.0 times the measured k value for the considered data. It is shown that the predictive capacity of this new equation may be extended to natural nonplastic silty soils, but not to crushed soils or plastic silty soils. The paper discusses several factors affecting the inaccuracy of predictions and laboratory test results.Key words: permeability, sand, prediction, porosity, gradation curve.
Stiffness degradation and shear strength of silty sands
Authors: Lee Junhwan , Salgado Rodrigo , Carraro J Antonio H
Published: October 2004

Soils behave nonlinearly from very early loading stages. When granular soils contain a certain amount of fines, the degree of nonlinearity also changes, as stiffness and strength characteristics vary with fines content. Hyperbolic stressstrain models and variations of these models are often used for description of the nonlinear behavior. A modified hyperbolic stressstrain relationship is used in this paper for representing the degradation of the elastic modulus of silty sands. The model is based on two modulus degradation parameters that determine the magnitude and rate of modulus degradation as a function of stress level. Realistic representation of soil behavior using this nonlinear relationship requires estimation of the degradation parameters as a function of silt content and relative density DR. A series of triaxial test results on sands containing different amounts of nonplastic silt were analyzed with this purpose. Relationships between the degradation parameters and cone penetration test (CPT) cone resistance qcare also proposed.Key words: hyperbolic model, silty sands, triaxial tests, modulus degradation, stressstrain response, shear strength, Gmax.