bluuebunny/crossref_metadata_2025 huggingface dataset:
Blackriveran (lower Mohawkian, Upper Ordovician) lithostratigraphy, rhythmicity, and paleogeography: Ottawa Embayment, eastern Ontario, Canada
Authors: Hersi O Salad , Dix G R
Published: April 2011

The Ottawa Embayment contains erosional remnants of a shallow-water carbonate platform (St. Lawrence Platform) of Late Ordovician (Caradocian) age. Stratigraphy of three Blackriveran formations - in ascending order, Pamelia, Lowville, and Chaumont - documents regional changes in continuity and types of depositional facies. The Pamelia Formation contains two members, each containing basin-wide basal siliciclastic units overlain by interbedded limestone, dolostone, and shale. An alternate division recognizes six shallowing-upward units; regionally extensive, intertidal to supratidal, dolomitic sandstone and (or) sandy dolostone define their tops. Sedimentary structures and isotope (C, O) geochemistry support a syngenetic origin of this stratigraphic (bedded) dolomite. The Lowville Formation contains two facies associations: subtidal to lower intertidal bioclastic and oolitic packstone - grainstone followed by lagoonal to intertidal mudflat facies. Lateral facies continuity is reduced compared to the Pamelia Formation. The Chaumont Formation contains thick beds of burrowed, bioclastic, peloidal mudstone to packstone, and minor shale. No rhythmic pattern is recognized in these subtidal facies. Upsection decrease of rhythmic sedimentation, with a decrease in lateral facies continuity of the studied strata reflects a progressive increase in net accommodation space related to Taconic transgression. Higher order rhythmicity of dolostone and sandstones of the Pamelia Formation can be traced into adjacent regions (New York and Kingston, Ont.). Dolomitic units may identify basin-wide chronostratigraphic markers, potentially useful for future sequence analysis. Regional correlation reveals a good oceanographic linkage between the Ottawa Embayment and the Appalachian Basin during Pamelia time and a restricted access across a paleohigh in the Montréal region. By the time of Lowville deposition, Taconic transgression had breached this restriction.
Reconstruction of sea-surface temperature, salinity, and sea-ice cover in the northern North Atlantic during the last glacial maximum based on dinocyst assemblages
Authors: Vernal Anne de , Hillaire-Marcel Claude , Turon Jean-Louis , Matthiessen Jens
Published: April 2011

Past sea-surface conditions over the northern North Atlantic during the last glacial maximum were examined from the study of 61 deep-sea cores. The last glacial maximum time slice studied here corresponds to an interval between Heinrich layers H2 and H1, and spanning about 20-16 ka on a 14C time scale. Transfer functions based on dinocyst assemblages were used to reconstruct sea-surface temperature, salinity, and sea-ice cover. The results illustrate extensive sea-ice cover along the eastern Canadian margins and sea-ice spreading, only during winter, over most of the northern North Atlantic. On the whole, much colder winter prevailed, despite relatively mild conditions in August (10-15°C at most offshore sites), thus suggesting a larger seasonal contrast of temperatures than today. Lower salinity than at present is reconstructed, especially along the eastern Canadian and Scandinavian margins, likely because of meltwater supply from the surrounding ice sheets. These reconstructions contrast with those established by CLIMAP on the basis of planktonic foraminifera. These differences are discussed with reference to the stratigraphical frame of the last glacial maximum, which was not the coldest phase of the last glacial stage. The respective significance of dinocyst and foraminifer records is also examined in terms of the thermohaline characteristics of surface waters and the vertical structure of upper water masses, which was apparently much more stratified than at present in the northern North Atlantic, thus preventing deep-water formation.
Geological setting and paleobotany of the Joffre Bridge Roadcut fossil locality (Late Paleocene), Red Deer Valley, Alberta
Authors: Hoffman Georgia L , Stockey Ruth A
Published: April 2011

The Joffre Bridge Roadcut locality (Paskapoo Formation) in south-central Alberta yields plant, mammal, fish, and insect fossils. A Late Paleocene (Tiffanian) age is indicated by mammalian fossils, supported by magnetostratigraphy and palynostratigraphy. This paper summarizes the flora (28 taxa have been identified to date) and describes the sedimentology to provide a paleoenvironmental context. Outcrops at the site are limited, but seven stratigraphic units are recognized and are interpreted to represent five environments of deposition: flood plain, fluvial channel, abandoned channel, swamp, and crevasse splay. The flood-plain mudstones lack identifiable plant material due to bioturbation and pedogenesis. They are capped by a thin, clay-rich paleosol with scattered vertebrate bones. An upward-fining sequence, interpreted as fluvial channel and channel abandonment sediments, rests directly on the paleosol and includes remains of riparian trees. Carbonaceous mudstone, interpreted as a swamp facies, includes remains of only five taxa (taxodiaceous conifers and riparian trees). Light-coloured mudstones on top of the swamp facies include a more diverse assemblage (aquatic and understory plants, taxodiaceous conifers, and riparian trees). Those beds are interpreted as the distal margin of an encroaching crevasse splay. Overlying sediments coarsen upward and are unfossiliferous, except for one occurrence of articulated fish skeletons from a mass-death event. The most productive beds for plant fossils are the top of the channel-abandonment sequence, the swamp horizon, and the base of the crevasse splay. Those beds have also yielded some insect, fish, and mammal remains.
Structural relations between the polydeformed Flin Flon arc assemblage and Missi Group sedimentary rocks, Flin Flon area, Manitoba and Saskatchewan
Authors: Gale D F , Lucas S B , Dixon J M
Published: April 2011

The structure of the Flin Flon area (Manitoba and Saskatchewan) has been examined through mapping of mesoscopic and macroscopic structures in both the ca. 1900 Ma Flin Flon arc assemblage volcanic basement and the unconformably overlying (or fault juxtaposed) ca. 1845 Ma Missi Group continental sedimentary cover sequence. The Flin Flon and Callinan volcanogenic massive sulphide orebodies occur within the basalt-dominated basement. The contact between the basement and the cover rocks was investigated in detail during this study. The cover sequence records three principal fold- and foliation-forming events. All deformation observed within the cover sequence is correlative with deformation observed within the volcanic basement. Significant low-angle overlap of basement on cover is attributed to development of a D1 north-verging nappe and subsequent thrust displacement on the overturned basement-cover contact. North-verging D1 structures provide evidence for a distinct post-Missi Group deformation event that preceded regional, southwestward D2 thrusting at peak metamorphic conditions across the southeastern Trans-Hudson Orogen. D2 deformation produced closed to tight, west-verging overturned folds with a well-developed axial planar cleavage and a pervasive extension lineation. D3 deformation generated open folds of the S2 and a weakly to moderately developed spaced axial planar S3 cleavage. D3 and D4 deformations produced sinistral-oblique, brittle-ductile reverse faults that offset all older features.
Major end moraines of Younger Dryas age on Wollaston Peninsula, Victoria Island, Canadian Arctic: implications for paleoclimate and for formation of hummocky moraine
Authors: Dyke Arthur S , Savelle James M
Published: April 2011

Some of the most extensive and massive end moraines of Younger Dryas age (1110 14C ka BP) yet recognized in North America occur on Wollaston Peninsula of Victoria Island. On the western part of the peninsula, numerous closely spaced end moraines formed in the interval starting 11 100 ± 100 radiocarbon years ago and ending about 10 50010 200 years ago. Net recession was generally slow throughout and was punctuated by moraine-building and at least two readvances. Recession is mapped with a resolution that is approximately decadal. The moraines form an orderly, nested succession and are consistently associated with westward shedding of meltwater, which formed a sequence of marine-limit deltas. We lack firm, independent proxy-climate evidence needed to assess whether these moraines formed because of cold Younger Dryas climate, rather than because of controls such as topographic setting and water depth, but climatic control seems probable. The moraines evidently retain glacier ice cores, as do most similarly large moraines in the Canadian Arctic Archipelago and northern mainland. They formed along active ice margins when the glacier mass balance on average was only slightly negative. Future melting of ice cores would produce regional hummocky moraine and much basal meltout till more than 10 000 years after deglaciation. Some southern areas of hummocky moraine may have originated as ice-cored moraines formed by active ice margins rather than from extensive regional stagnation.
The Lithoprobe Abitibi-Grenville transect: two billion years of crust formation and recycling in the Precambrian Shield of Canada
Authors: Ludden John , Hynes Andrew
Published: April 2011

We summarize the results of Lithoprobe studies in the Neoarchean southeastern Superior Province and the Mesoproterozoic Grenville Province, in the southeastern Precambrian Shield of Canada, through two composite cross-sections based on seismic reflection data, which define dramatically different styles of crust formation and tectonic accretion in the Neoarchean and Mesoproterozoic. In the Neoarchean, the structures at the surface are steep, with discontinuous and flatter structures at depth, much of the crust appears to be juvenile, and the predominant process of crustal growth is inferred to have been subduction-accretion of primitive crust in a prograding arc system. In the Mesoproterozoic, surface structures are shallow and the seismic character of the crust is continuous over the entire cross-section. Archean parautochthonous rocks and reworked Archean crust comprise a very significant proportion of the preserved crust in the Mesoproterozoic and provided the backstop to the Grenvillian orogeny, resulting in the exhumation of crustal rocks formed at high pressures. Preservation of Neoarchean crust, including a thickened lithosphere in the Superior Province, in contrast to its general destruction in younger orogens, may well relate to a unique thermal regime at this time on Earth.
Modelling 3D architecture of western Grenville from surface geology, xenoliths, styles of magma emplacement, and Lithoprobe reflectors
Authors: Corriveau Louise , Morin David
Published: April 2011

Information derived from regional geology, styles of magma emplacement, xenoliths, and western Grenville Lithoprobe reflectors is integrated to model the architecture of the Central Metasedimentary Belt in Quebec. The belt comprises a thin-skinned western marble domain that projects structurally to the east above a quartzite domain; both domains are underlain by a series of gneiss domes. In contrast, the seismic reflectors dip systematically to the east. They stem from exposed high-strain zones and tectonic boundaries hosting concordant, 1.7-1.16 Ga, postmetamorphic sheetlike plutons. Though discontinuous, the reflectors reach highly reflective crust segments near the Moho. The reflections are interpreted as series of plutons positioning crustal-scale structures rooted in underplated, felsic, and mafic magmas reservoirs. These structures served as magma conduits and ponding sites. The nonreflective segments of the inferred structures are interpreted as through-going pathways for magmas in gneissose crust. Based on the thousands of felsic to ultramafic xenoliths brought up by a 1.07 Ga minette dyke, the nature of the intermediate and lower crust is interpreted as interleaving of nonexposed quartzite-bearing supracrustal assemblages with mylonites, gneisses, and a series of mafic to ultramafic intrusive bodies, many of them inferred to be underplated material. In western Quebec, crustal growth along the pre-Grenvillian Laurentian margin involved pre-1.2 Ga stacking of allochthons including nonexposed metasedimentary and intrusive components during an early stage of Grenvillian collision. Subsequent, 1.7-1.6 Ga magma emplacement along high-strain zones shaped much of the seismic reflectivity of the belt.
Intraspecific variation in sex heterochromatin of species B of the Anopheles dirus complex in Thailand
Authors: Baimai V. , Traipakvasin A.
Published: April 2011

Cytological examination of F1 larval mitotic chromosomes from a total of 126 families of Anopheles dirus species B from southern Thailand populations has revealed a pronounced quantitative variation of constitutive heterochromatin in the two sex chromosomes. Five types of X chromosomes and four types of Y chromosomes have been identified in this study. Such gross variation in sex chromosomes is most likely due to a gradual acquisition of extra heterochromatin.

Key words: Anopheles, heterochromatin variation, coevolution, sex chromosomes.
A separate control for frequency and within-bivalent distribution of chiasmata in rye (Secale cereale L.)
Authors: Lein V. , Lelley T.
Published: April 2011

Six genetically different inbred genotypes of spring-type rye Secale cereale with differences in the average number and in the positional distribution of chiasmata were used in this study. The line with the lowest chiasma frequency was chosen as the female parent and crossed with the other five lines. Parental, F1, and F2 data were collected on chiasma number and on chiasma distribution between and within bivalents. Evidence for a polygenic control of both phenomena was found. Chiasma distribution between bivalents within pollen mother cells obviously follows a binomial distribution. This is effected by a mechanism that prevents the formation of a second chiasma on a chromosome arm as long as chromosome arms without chiasma remain; i.e., with 14 chiasmata seven ring bivalents will generally be formed. This mechanism causes a very strong negative correlation between frequency and between-cell variance of chiasmata. The number of chiasmata is independent of their position within the bivalents. A very close correlation between the number of pollen mother cells without univalents and the number of fertile pollen grains was found.

Key words: inbred rye, genetic control, chiasma frequency, chiasma distribution, heterosis.
The effect of gamma radiation on recombination frequency in Caenorhabditis elegans
Authors: Kim J. S. , Rose A. M.
Published: April 2011

We have studied the effect of gamma radiation on recombination frequency for intervals across the cluster of linkage group I in Caenorhabditis elegans. Recombination frequency increased approximately twofold across the dpy-5–unc-13 interval after treatment with 2000 rads (1 rad = 10 mGy) of cobalt 60 gamma radiation. Several factors affecting the magnitude of the increase have been characterized. Recombination frequency increased more with higher doses of radiation. However, the increase in recombination frequency with increasing dose was accompanied by a reduced average number of progeny from radiation-treated individuals. The amount of the increase was affected by meiotic stage, age at the time of treatment (premeiotic), and radiation dose. The increase in recombination was detectable in the B brood and remained elevated for the remainder of egg production. X-chromosome nondisjunction was also increased by radiation treatment. A high frequency of the recombinant progeny produced with radiation treatment were sterile unlike their nonrecombinant siblings. When parameters affecting recombination frequency are held constant during treatment, chromosomal regions of high gene density on the meiotic map increased more (fourfold) than an adjacent region of low gene density (no increase). The greatest increase was across the dpy-14–unc-13 interval near the center of the gene cluster. These results may suggest that the physical length of DNA per map unit is greater within the cluster than outside.

Key words: recombination, radiation, nondisjunction, map expansion, genetic map.
Chromosome location and linkage of a new gene (Lr33) for reaction to Puccinia recondita in common wheat
Authors: Dyck P. L. , Kerber E. R. , Lukow O. M.
Published: April 2011

A gene for resistance to Puccinia recondita, originally detected in wheat (Triticum aestivum L.) accessions PI58548, PI268454, and PI268316, has been located on the long arm of chromosome 1B, 3.1 ± 1.2 crossover units from the centromere. In a cross between the backcross line RL6057 containing this new gene, now designated Lr33, and the backcross line RL6078 containing gene Lr26, gene Lr33 is closely linked to gene Lr26 (or the translocation breakpoint) with an estimated 2.6 ± 0.8 recombination value. RL6057 and RL6078 differ in gliadin bands that are controlled by genes on the short arm of chromosome 1B or 1R. The banding difference was completely associated with the presence or absence of Lr26.

Key words: Triticum, Puccinia, linkage.
Inheritance and expression of tissue-specific catalase activity during development and aging in mice
Authors: Schisler N. J. , Singh S. M.
Published: April 2011

The catalase activity in the liver, kidney, lung, and blood hemolysate was measured in newborn, 21-, 70-, 175-, and >400-day-old mice from the strains BALB/c, Csb, C3H/HeSnJ, C3H/S, C57BL/6J, SW, and 129/ReJ. Catalase activity was found to be highest in the liver (~0.33 U/mg protein) followed by the kidney (~0.13 U/mg protein), lung (~0.05 U/mg protein), and blood hemolysate (~0.03 U/mg protein). ANOVA analysis indicated significant differences in enzyme activity among strains and age groups studied. The developmental profiles of enzyme activity were tissue and strain specific. Catalase activity in the blood, for example, was generally higher at birth and at old age, whereas the kidney catalase activity was low at birth and increased substantially with age. Strains could be classified as normal (129/ReJ, BALB/c, C3H/HeSnJ, C3H/S), hypocatalasemic (C57BL/6J, SW), and acatalasemic (Csb) with respect to enzyme activity and it was on this basis that the inheritance of the catalase phenotype was studied using appropriate crosses. The enzyme activity level in each tissue appears to be governed by a unique set of genetic regulators/modifiers that interact with a single structural gene (Cs) or its product to produce the catalase phenotype. Some of these (e.g., Ce-1 and Ce-2) have been previously described but based on the results of various crosses reported here, more must exist that remain still uncharacterized at the molecular level. Models proposed for the inheritance of the catalase phenotype vary in complexity from single allelic differences between strains (e.g., BALB/c × Csb; blood) to a system of multiple interacting genetic determinants (e.g., BALB/c × Csb; liver) each having dominant (e.g., C57BL/6J over BALB/c; liver) and recessive components (e.g., gene(s) conferring the acatalasemic phenotype in BALB/c × Csb; blood and kidney). Such results are important and offer an interesting model to further characterize aspects of eukaryotic gene regulation.

Key words: catalase, inbred mice, tissue specificity, developmental profile, inheritance.
Among- and within-population variability for forage yield and Fusarium resistance in birdsfoot-trefoil
Authors: Hill Jr. R. R. , Zeiders K. E.
Published: April 2011

Polycross families of birdsfoot-trefoil, Lotus corniculatus L., were evaluated in the greenhouse for number of live plants 120 days after inoculation with Fusarium oxysporum (Schlecht) Snyd. & Hans, and in the field for forage yield and stand scores. The parents of the polycross progenies came from 11 different birdsfoot-trefoil cultivars. The objective of the experiment was to determine relative importance of source population and parents within source population as sources of variability for reaction for F. oxysporum, forage yield, and stand score. Expected values for means of polycross families within source populations and for source populations were expressed in terms of parameters from a previously developed autotetraploid genetic model. All genetic effects were present in the equations, but variation among source populations would be important only if the source populations differed in gene frequencies. Source populations were the only significant source of variation for the number of live plants 120 days after inoculation with F. oxysporum and the stand score. A significant year by source population interaction was observed for total season yield. The correlation between number of live plants in the greenhouse and the stand score was significant. We concluded (i) selection of source population was important when breeding for resistance to F. oxysporum or improved stand but not for total season yield, and (ii) successful breeding for resistance to F. oxysporum would contribute to improved persistence in birdsfoot-trefoil.

Key words: Lotus corniculatus L., Fusarium oxysporum, polycross progeny, selection.
Inheritance and linkage relationships of 6-phosphogluconate dehydrogenase isozymes in soybean
Authors: Chiang Y. C. , Kiang Y. T.
Published: April 2011

The inheritance of 6-phosphogluconate dehydrogenase (6-PGD) in dry seeds of cultivated and wild soybean was studied electrophoretically. There are four 6-PGD anodal bands that are controlled by three loci. Bands 1 and 3 are homodimers, whereas band 2 is the interlocus heterodimer of bands 1 and 3, which are products of the Pgd1 and Pgd2 loci, respectively. Both Pgd1 and Pgd2 loci have three codominant alleles (Pgd1-a, Pgd1-b, Pgd1-c and Pgd2-a, Pgd2-b, Pgd2-c) and each of the alleles specifies an isozyme band. The two variants of the fourth band are the result of two codominant alleles (Pgd3-a and Pgd3-b) of the Pgd3 locus. The Pgd3-a allele is found only in PI486.220, a Glycine soja accession from Japan. The Pgd2 is linked to Ap, Ti, and Lap1 in the order of Ap–Ti–Lap1–Pgd2 and belongs to linkage group 9.

Key words: soybean isozymes linkage, genetics of Pgd loci.
Metaphase association of mammalian chromosomes
Authors: Mayr-Wohlfart U. , Adolph S. , Klett Ch. , Hameister H.
Published: April 2011

The association behavior of chromosomes bearing nucleolar organizer region (NOR) and (or) C-heterochromatin in metaphase plates was analyzed. Different species with an informative chromosomal localization of NOR and C-heterochromatin were evaluated. Several examples indicate that the well-known metaphase association is not due to NORs or NOR activity per se. Other mechanisms such as ectopic pairing are responsible for the association. These types of pairing seem to be enhanced by the chromatin-decondensing effect of nearby NOR activity.

Key words: NOR, C-heterochromatin, metaphase association.
The cytogenetic relationship between Cicer judaicum Boiss. and Cicer chorassanicum (Bge.) M. Pop.
Authors: Ahmad F. , Slinkard A. E. , Scoles G. J.
Published: April 2011

A single plant was produced of the interspecific hybrid Cicer judaicum Boiss. (2n = 16) × Cicer chorassanicum (Bge.) M. Pop. (2n = 16), but none was produced from the reciprocal cross. The hybrid plant was intermediate in morphology between the parental species with the dominant purple flower color of C. judaicum. The hybrid plant had a diploid somatic chromosome number of 2n = 16 and was characterized cytologically. The hybrid had a low chiasmata frequency (5.4 ± 1.2 vs. 12.1 and 11.4 in the parental species) per cell and was highly sterile. The flowers were abnormal in that the stigma and style grew out of the keel, while the anthers remained inside. Sterility and abnormal floral structure may play important roles in maintenance of species identity.

Key words: interspecific hybrid.
Estimation of population fitness of parental races Drosophila nasuta nasuta and Drosophila nasuta albomicana and of the newly evolved Cytoraces I and II
Authors: Ramachandra N. B. , Ranganath H. A.
Published: April 2011

Interracial hybridization between Drosophila nasuta nasuta (2n = 8) and Drosophila nasuta albomicana (2n = 6) has resulted in the emergence of new karyotypic strains called Cytorace I (♀ 2n = 7; ♂ 2n = 6) and Cytorace II (♀ and ♂ 2n = 6). The parental and the newly evolved Cytoraces were assessed for parameters of fitness, i.e., fecundity, egg to adult rate of development, egg to adult viability, and adaptedness. The newly evolved Cytoraces not only differ from each other but also differ from their parental races in their fitness phenotypes. Each one of these four strains represent features of different genetic systems with different adaptive phenotypes.Key words: Drosophila, interracial hybridization, population fitness.
Quantitative genetics of allotetraploid and autotetraploid populations
Authors: Ehlke N. J. , Hill Jr. R. R.
Published: April 2011

Theoretical studies were conducted to compare quantitative genetic parameters in hypothetical allotetraploid and autotetraploid populations with the same genetic information. Concepts of factorial experiments and methods of direct product matrix algebra were used to express genetic effect contrasts in similar forms for each ploidy type. Quantitative genetic effects could be expressed as follows: (i) the population mean; (ii) four linear contrasts that could be equated to additive effects with either ploidy type; (iii) six contrasts resulting from interactions between two alleles, two of these equated to dominance effects and four to additive × additive effects in the allotetraploid and all six equated to digenic effects in the autotetraploid; (iv) four contrasts from interactions between three alleles, which equated to additive × dominance effects in the allotetraploid and to trigenic effects in the autotetraploid; and (v) one contrast that resulted from interactions between four alleles, which equated to the dominance × dominance effect in the allotetraploid and the quadrigenic effect in the autotetraploid. In hypothetical populations for which gene functions were the same and gene frequencies were equal, contrasts involving similar numbers of genes were identical for each ploidy type. The mean and total variance of the hypothetical populations would be identical. The parent–offspring covariance, variance among half-sib families, and the variance among full-sib families would be slightly larger in allotetraploid than in autotetraploid populations for traits affected by genes with nonadditive effects. We concluded that response to recurrent selection, general combining ability in diallel crosses, and the probability of finding a superior single cross hybrid would be larger in the allotetraploid than in the autotetraploid populations when nonadditive genetic effects are present. The relationship between ploidy types for specific combining ability in diallel crosses depended on the importance of digenic effects. Plant breeders working on species with autotetraploid inheritance should consider looking for allotetraploid forms before embarking on programs to produce hybrid cultivars.Key words: genetic variance; covariance, parent–offspring; breeding behavior; matrix algebra.
Assignment of the genomic affinities of chromosomes from polyploid Elymus species added to wheat
Authors: Gill Bikram S. , Morris Kay L. D. , Appels Rudi
Published: April 2011

Genomic DNAs from 10 disomic addition, substitution, or translocation chromosomes from tetraploid Elymus trachycaulus (SSHH) and 13 tetraploid Elymus ciliaris (SSYY) in Chinese Spring wheat were assayed with 18S–28S rDNA (Nor), 5S DNA, Adh, α-amylase, β-glucanase gene clones, and S-genome and H-genome repetitive DNA sequences. The rDNA from the S genome and 5S DNA from the S and H genomes, under high stringency Southern blot analysis, distinguished S-genome and H-genome loci on individual Elymus chromosomes. The single gene, or low copy gene probes (Adh and others), allowed identification of different addition lines and provided information on the gene synteny relationships of Elymus chromosomes with wheat chromosomes. The S-genome specific and H-genome repetitive DNA probes were not useful in assigning genomic affinities, due to some cross-hybridization between these genomes using these probes and (or) the occurrence of large numbers of translocations in polyploid genomes of Elymus species. However, the repetitive DNA probes provided diagnostic phenotypic markers for identification of individual Elymus addition lines. Moreover, since S- and H-genome DNA sequences were virtually absent from wheat, they were excellent markers for the detection of Elymus chromatin in wheat. The array of DNA probes should prove useful in chromosome manipulation in resistance transfer from Elymus into wheat.Key words: Triticeae, Elymus, aneuploid, DNA probe.
Genetic analysis of the dwarf curly leaf tomato mutant via hybridization with Curl and dwarf mutants
Authors: Yu M. H.
Published: April 2011

The characteristics of the dwarf curly leaf tomato (Lycopersicon esculentum Mill.) mutant, cu-3, were investigated via hybridization with the Curl, Cu, and dwarf, dcr, mutants. When Cu plants were crossed to cu-3 or dcr parents, F1 plants expressed the Cu phenotype, whereas two parental and two nonparental types were present in each F2. The transgressive groups were the wild type (+), which developed normal expanded leaves, and the midvein-invisible type (MI), which developed extremely distorted curly leaves. Crosses between cu-3 and dcr plants produced nonparental wild-type plants in F1, and two parental and one wild type in F2. There was no allelism or linkage between cu-3 and Cu, dcr, or dpy (the dumpy mutant). Cu was epistatic to both cu-3 and dcr. The cu-3 allele was epistatic to dcr; however, dcr plants (in the cu-3+cu-3 dcr dcr genotype) could produce cu-3 progeny. The cu-3 plants always bred true, cu-3 hindered the Cu-type progeny from becoming a majority group in Cu and cu-3 hybridizations. Both cu-3 and cu-3+ caused >33% decrease in fruit size of Cu, dcr, +, and MI progeny of their Cu and dcr hybrids; a >50% decrease in seed number per fruit was evident in such progeny of the cu-3 hybrids.Key words: Lycopersicon esculentum Mill., L. pimpinellifolium (Jusl.) Mill., epistatic effects, recombinant types, transgressive groups.
Distribution of a Secale cereale DNA repeat sequence among 25 Hordeum species
Authors: Gupta P. K. , Fedak G. , Molnar S. J. , Wheatcroft Roger
Published: April 2011

DNA of 61 accessions representing 25 Hordeum species was tested for homology to a highly repeated 120-bp sequence from Secale cereale (rye). Homology to the probe (pSC119) was detected in dot blots of all species except H. vulgare (cultivated barley) and its related species, H. agriocrithon and H. spontaneum. Hybridization patterns of Southern blots of restriction fragments demonstrated both intraspecific and interspecific variation in the organization of complex units of DNA having homology to the probe. For eight species, digestion of the DNA with BamHI gave ladder patterns characteristic of tandem arrays of 120-bp repeat units. For EcoRI, HindIII, and SacI digests, the hybridization patterns appeared to be highly conserved in the section Hordeum, except those for H. bulbosum, which were unique. A further set of patterns for these three enzymes was common among the remaining species of the genus. Thus, DNA hybridization with pSC119 generally gave patterns consistent with the current taxonomy of Hordeum species, except that H. bulbosum and H. vulgare were not shown to be closely related.Key words: Hordeum, repeated DNA sequences, pSC119, species variation.
Chromosomal alterations and DNA content in rats during ageing
Authors: Sen Sarmistha , Talukder Geeta , Sharma Archana
Published: April 2011

Chromosome analysis of bone marrow cells from 96 sex-matched Rattus norvegicus of 12 different age groups showed a significant increase in hypodiploid cells with ageing. However, in meiotic preparations from gonadal cells of male rats the frequency of hypodiploid or hyperdiploid cells did not change significantly. In situ DNA estimation of bone marrow nuclei, following Feulgen cytophotometry, also did not show any significant difference with gradual age changes.Key words: senescence, DNA content, age-related changes.
High-resolution R-banding at the 1250-band level. II. Schematic representation and nomenclature of human RBG-banded chromosomes
Authors: Drouin Régen , Richer Claude-Lise
Published: April 2011

Detailed characterization of the RBG-banding pattern at the 1250-band level has been done after thymidine synchronization and block release with 5-bromo-2′-deoxyuridine (BrdU), which induces chromosome elongation and improves definition of chromosomal bands. Optimal conditions for the incorporation of BrdU and the use of the FPG (fluorochrome–photolysis–Giemsa) technique produced excellent band separation and band contrast even in highly elongated prophase chromosomes. Moreover, we did not observe lateral asymmetry in C-banded regions. The schematic representation of these elongated chromosomes in the 1250-band range per haploid set was prepared showing the relative position, the specific size, and the characteristic staining intensity for each band. To this idiogram was extended the International Standard Cytogenetic Nomenclature. This realistic idiogram should help in the preparation of R-banded prophase karyotypes and in the identification and localization of chromosomal rearrangements. Because differences exist between RBG and RHG bands, a brief comparative description of each RBG-banded chromosome is included. Moreover, a minute analysis of the banding pattern revealed that various parts of chromosomes contract differently. We also observed the presence of R-positive bands in heterochromatic regions of the short arms of the acrocentrics, and of chromosomes 1, 9, 16, and Y.Key words: high-resolution chromosome banding, R-banding, idiogram, dynamic bandings, prophase chromosomes, chromosome banding by BrdU incorporation.
A second locus for the 5S multigene family in Secale L.: sequence divergence in two lineages of the family
Authors: Reddy P. , Appels R.
Published: April 2011

The 5S RNA genes in Secale sp. are arranged as tandem arrays of a 460- and 480-bp repeating sequence. These size classes were initially discovered by restriction endonuclease analysis using BamHI and subsequently by DNA sequencing of cloned units. The length variation between short and long units originated from major deletion–insertion events in the noncoding spacer region of the 5S DNA repeat units. In situ hybridization with [3H]cRNA and biotin-labelled probes synthesized from both the short and long 5S DNA units of S. cereale localized the sites on chromosome 1R and a new site on a chromosome identified as 5R. We propose that the chromosome 1R locus, which has been mapped previously, be named 5SDna-R1 and the second locus, reported in the present paper, be referred to as 5SDna-R2. A preferential hybridization of a probe from the long unit to the 5SDna-R2 locus and of a probe from the short unit to the 5SDna-R1 locus is reported. The clustering of long units in the 5SDna-R2 locus was confirmed by restriction endonuclease digestion of DNA from rye chromosome 5R additions to wheat. Nucleotide sequence alignment of 5S DNA repeat units from a number of Secale species, using both phenetic and cladistic computer programmes, demonstrated that two clear lineages corresponding to the long and short units existed in this genus. The different Secale species could not be unambiguously differentiated using the 5S DNA sequences.Key words: Secale, 5S multigene family, restriction mapping, molecular evolution.
A method for the formulation of Reynolds number functions
Authors: da Silva Ana Maria AF , Bolisetti Tirupati
Published: April 2011

A general method for the formulation of flow characteristics which are functions of the Reynolds number of the system is presented. It is assumed that the flow characteristics exhibit a strong variation with the Reynolds number when the Reynolds number is "small," and that they become independent of it when the Reynolds number is "large." The method is illustrated by finding mathematical expressions for the experimentally determined "roughness" function curve and for the sediment transport initiation curve (Shields' curve), which are relevant for the analysis of flow and sediment transport in pipes and open channels. The two expressions thus obtained can be used in practice for computational purposes.Key words: Reynolds number functions, mathematical expression, roughness function, Shields' curve.
Fibre reinforced polymer shear reinforcement for concrete members: behaviour and design guidelines
Authors: Shehata Emile , Morphy Ryan , Rizkalla Sami
Published: April 2011

This paper describes an experimental program conducted to examine the structural performance of fibre reinforced polymer (FRP) stirrups as shear reinforcement for concrete structures. A total of ten large-scale reinforced concrete beams were tested to investigate the contribution of the FRP stirrups in a beam mechanism. The ten beams included four beams reinforced with carbon fibre reinforced polymer (CFRP) stirrups, four beams reinforced with glass fibre reinforced polymer (GFRP) stirrups, one beam reinforced with steel stirrups, and one control beam without shear reinforcement. The variables were the material type of stirrups, the material type of the flexural reinforcement, and the stirrup spacing. Due to the unidirectional characteristics of FRP, significant reduction in the strength of the stirrup relative to the tensile strength parallel to the fibres is introduced by bending FRP bars into a stirrup configuration and by the kinking action due to inclination of the diagonal shear crack with respect to the direction of the stirrups. A total of 52 specially designed panel specimens were tested to investigate the bend and kinking effect on the capacity of FRP stirrups, along with two control specimens reinforced with steel stirrups. The variables considered in the panel specimens are the material type of the stirrups, the bar diameter, the bend radius, the configuration of the stirrup anchorage, the tail length beyond the bend portion, and the angle of the stirrups. Based on the findings of this investigation, shear design equations for concrete beams reinforced with FRP, appropriate for the Canadian Standards Association (CSA) code, are proposed. The reliability of the proposed equations is evaluated using test results of 118 beams tested by others.Key words: shear, fibre-reinforced polymers, CFRP, cracks, GFRP, kink, stirrups, bend capacity.
Effects of temperature on the behaviour of fiber reinforced polymer reinforced concrete members: experimental studies
Authors: Elbadry Mamdouh M , Abdalla Hany , Ghali Amin
Published: April 2011

Thermal characteristics of fiber reinforced polymer (FRP) reinforcement can be substantially different from those of concrete and conventional steel reinforcement. The influence of this difference on the behaviour of FRP reinforced concrete members is studied in this paper. Concrete beams reinforced with different types of FRP rebars are tested under the effects of temperature gradient while the rotation at the two ends of the beam are restrained. The bending moments and cracking developed by the thermal gradient are monitored. The results are compared with those obtained from tests on beams of the same dimensions but reinforced with steel bars. The behaviour of thermally cracked members is also investigated under mechanical load effects at both service and ultimate load levels. The potential cracking of the concrete cover caused by the transverse thermal expansion of FRP bars is examined by testing concrete cylinders. The experiments show the difference in thermal behaviour of glass and carbon FRP and steel bars.Key words: bond, concrete, cracking (fracturing), fiber reinforced polymers, loads (forces), reinforcement, temperature, tensile strength, thermal expansion, thermal stresses.
Composite reinforcement of timber in bending
Authors: Johns Kenneth C , Lacroix Simon
Published: April 2011

A promising use for high performance composite materials is to reinforce timber beams. The present paper studies the use of carbon and glass fibres to reinforce sawn timber sections. Consideration is given to strength phenomena of commercial timber alone and in reinforced sections in bending and shear. Anchorage length considerations for composite strips applied to the underside of simple beams are discussed. Experimental results are presented for three geometries of reinforcement using matched samples of 25 pairs of beams, reinforced and not. Results establish that the wood itself in the composite section shows strength increase, and that the increase in moment resistance of the reinforced beams is far greater than that predicted by simple models.Key words: composite material, timber, reinforcement, bending, shear.
A three-dimensional finite element model for locally reinforced timber joints made with hollow dowel fasteners
Authors: Guan Z W , Rodd P D
Published: April 2011

Brittle premature failure caused by splitting parallel to the timber grain is a common failure mode in glulam joints made with solid dowel type fasteners. It is thought that this problem can be alleviated by using hollow steel dowels as the fasteners and reinforcing the timber locally in the area of the joint. In this way, by varying the wall thickness of the dowels and the thickness of the reinforcing members, a chosen combination of strength and stiffness should be attainable together with a ductile failure mode. In this paper, three-dimensional nonlinear finite element models are developed to simulate (i) the structural performance of a timber joint made with a single hollow steel dowel and (ii) a moment transmitting joint made with a number of the dowels, each type being locally reinforced by densified veneer wood. The models incorporate suitably defined elastoplasticity and orthotropic elasticity and also allow for large deformations of the joints as well as for frictional contact between the timber and the dowel. They are calibrated against physical test data from joints loaded to failure.Key words: glulam, densified veneer wood, resin injected, hollow dowel fastener, moment transmitting, ductile failure, finite element.
Water temperature modelling in a small forested stream: implication of forest canopy and soil temperature
Authors: St-Hilaire André , Morin Guy , El-Jabi Nassir , Caissie Daniel
Published: April 2011

The demand for comprehensive environmental assessment of river ecosystem has increased for engineers and scientists. Accurate and versatile water temperature models are required to meet this demand. A number of hydrological models take vegetation and soil characteristics into account, but very few temperature models do. The objective of this paper is to incorporate soil temperature and vegetation as input variables in a deterministic heat budget model. The CEQUEAU hydrological and water temperature model was used to simulate water temperature in Catamaran Brook, a small catchment located in central New Brunswick. The model was modified by incorporating soil temperature as a parameter influencing the temperature of interflow, using the so-called force-restore method. Crown closure was also incorporated in the model as a factor influencing locally advected water using a negative exponential function. The modified model simulated daily water temperatures better than the original model. Root-mean-square error for a period of 5 years decreased from 2.10°C with the original model to 1.77°C with the modified model. Nash coefficient increased from 0.78 with the original model to 0.82 with the modified model. An analysis of residuals showed that the modified model is sensitive to additional parameters such as crown closure, especially for short time scales during periods of higher discharge and during extreme meteorological and hydrological events such as tropical storms.Key words: stream temperature, hydrology, deterministic model, CEQUEAU, forestry.
Proposed new Canadian wind provisions for the design of gable roofs
Authors: Stathopoulos Ted , Wang Kai , Wu Hanqing
Published: April 2011

Wind pressure coefficients for gable roofs of low buildings are strongly dependent on roof angle, particularly for intermediate roof slopes (roof angle 10°-30°). This paper addresses the suitability of wind pressure coefficients specified in the National Building Code of Canada (NBCC) for gable roofs in the intermediate slope range. In a recent research study, a series of low building models with different roof slopes were tested in a boundary layer wind tunnel under simulated open country conditions. This was different from the original study in the 1970s, which produced the current wind provisions on the basis of a model tested only for a single roof slope (4:12) in this intermediate roof slope range. The results of the study suggest that a modification of the wind provisions of NBCC would be warranted to make them more representative of the true local and area-averaged wind loads imposed on gable roofs of intermediate slope.Key words: building, code, design, pressure, roof, standard, wind.
Laboratory investigation on Fabry-Perot sensor and conventional extensometers for strain measurement in high performance concrete
Authors: Quirion Marco , Ballivy Gérard
Published: April 2011

Advances in fiber optic sensing technology have made possible the installation of an extremely precise and reliable sensor in small structural members. Because of the high sensitivity and fast response of the sensor, low strain and dynamic strain can be measured. In this study, a Fabry-Perot strain sensor was cast in a high performance concrete cylinder, which had been submitted to simple compression and thermal tests. These results were compared with measurements obtained using external linear variable differential transformers fixed on concrete samples having the same composition as the fiber optic instrumented concrete cylinder. Comparisons were also done with results from tests on concrete cylinders instrumented with embedment vibrating wire and electrical strain gauges. In addition, thermal tests were performed on the different concrete cylinders and samples in order to compare the behaviour of the different sensors in high performance concrete submitted to temperature variations. The results show that the concrete strains measured with the Fabry-Perot sensor are in agreement with strain measurements made on concrete samples. Consequently, the presence of the embedded fiber optic sensor does not influence greatly the mechanical properties of concrete. Furthermore, for high stress levels (0.4 f 'c) and rapid stress changes (0.25 MPa/s), the fiber optic sensor measures with higher accuracy the strains of high performance concrete than the vibrating wire strain gauge.Key words: high performance concrete, sensor, vibrating wire, strain, extensometer, Fabry-Perot, fiber optic, instrumentation.