bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular and Biochemical Analysis of Periplastidial Starch Metabolism in the Cryptophyte
Guillardia theta
Authors: Haferkamp Ilka , Deschamps Philippe , Ast Michelle , Jeblick Wolfgang , Maier Uwe , Ball Steven , Neuhaus H. Ekkehard
Published: June 2006

Starch in synchronously grown
Guillardia theta
cells accumulates throughout the light phase, followed by a linear degradation during the night. In contrast to the case for other unicellular algae such as
Chlamydomonas reinhardtii
, no starch turnover occurred in this organism under continuous light. The gene encoding granule-bound starch synthase (
GBSS1
), the enzyme responsible for amylose synthesis, displays a diurnal expression cycle. The pattern consisted of a maximal transcript abundance around the middle of the light phase and a very low level during the night. This diurnal regulation of
GBSS1
transcript abundance was demonstrated to be independent of the circadian clock but tightly light regulated. A similar yet opposite type of regulation pattern was found for two α-amylase isoforms and for one of the two plastidic triose phosphate transporter genes investigated. In these cases, however, the transcript abundance peaked in the night phase. The second plastidic triose phosphate transporter gene had the
GBSS1
mRNA abundance pattern. Quantification of the GBSS1 activity revealed that not only gene expression but also total enzyme activity exhibited a maximum in the middle of the light phase. To gain a first insight into the transport processes involved in starch biosynthesis in cryptophytes, we demonstrated the presence of both plastidic triose phosphate transporter and plastidic ATP/ADP transporter activities in proteoliposomes harboring either total membranes or plastid envelope membranes from
G. theta
. These molecular and biochemical data are discussed with respect to the environmental conditions experienced by
G. theta
and with respect to the unique subcellular location of starch in cryptophytes.
Cytogenetic analysis of myxoid liposarcoma and myxofibrosarcoma by array-based comparative genomic hybridisation
Authors: Ohguri T , Hisaoka M , Kawauchi S , Sasaki K , Aoki T , Kanemitsu S , Matsuyama A , Korogi Y , Hashimoto H
Published: June 2006

Aim:To investigate overall chromosomal alterations using array-based comparative genomic hybridisation (CGH) of myxoid liposarcomas (MLSs) and myxofibrosarcomas (MFSs).

Materials and methods:Genomic DNA extracted from fresh-frozen tumour tissues was labelled with fluorochromes and then hybridised on to an array consisting of 1440 bacterial artificial chromosome clones representing regions throughout the entire human genome important in cytogenetics and oncology.

Results:DNA copy number aberrations (CNAs) were found in all the 8 MFSs, but no alterations were found in 7 (70%) of 10 MLSs. In MFSs, the most frequent CNAs were gains at 7p21.1–p22.1 and 12q15–q21.1 and a loss at 13q14.3–q34. The second most frequent CNAs were gains at 7q33–q35, 9q22.31–q22.33, 12p13.32–pter, 17q22–q23, Xp11.2 and Xq12 and losses at 10p13–p14, 10q25, 11p11–p14, 11q23.3–q25, 20p11–p12 and 21q22.13–q22.2, which were detected in 38% of the MFSs examined. In MLSs, only a few CNAs were found in two sarcomas with gains at 8p21.2–p23.3, 8q11.22–q12.2 and 8q23.1–q24.3, and in one with gains at 5p13.2–p14.3 and 5q11.2–5q35.2 and a loss at 21q22.2–qter.

Conclusions:MFS has more frequent and diverse CNAs than MLS, which reinforces the hypothesis that MFS is genetically different from MLS. Out-array CGH analysis may also provide several entry points for the identification of candidate genes associated with oncogenesis and progression in MFS.
Receptor-activated Smad localisation in Bleomycin-induced pulmonary fibrosis
Authors: Higashiyama Hiroyuki , Yoshimoto Daisuke , Okamoto Yuji , Kikkawa Hideo , Asano Satoshi , Kinoshita Mine
Published: June 2006

Background:Recent advances in fibrosis biology have identified transforming growth factor (TGF)-β type I receptor-mediated activation of Smads as playing a central part in the development of fibrosis. However, to date, there have been few studies that examined the localisation and distribution of receptor-activated Smads protein (R-Smads: Smad2 and 3) during the fibrosis progression.

Aims:To histopathologically assess the time-course change of the localisation and distribution of the Smads protein in pulmonary fibrosis.

Methods:Pulmonary fibrosis was induced by intranasal injection of bleomycin (0.3 U/mouse). Lungs were isolated 2, 5, 7, 9 and 14 days after bleomycin treatment. Histological changes in the lungs were evaluated by haematoxylin-eosin stain or Masson’s trichrome stain, and scored. TGF-β1, Smad3 and phosphorylated Smad2 localisations in lung tissues were determined by immunohistochemistry.

Results:The bleomycin treatment led to considerable pulmonary fibrotic changes accompanied by marked increase in TGF-β1 expression in infiltrating macrophages. With the progression in fibrosis (day 7–14), marked increases in Smad3-positive and pSmad2-positive cells were observed. There were intense Smad3-positive and pSmad2-positive signals localised to the nuclei of the infiltrating macrophages and to type II epithelial cells, and less intense signals in fibroblasts and hyperplastic alveolar/bronchiolar epithelial cells.

Conclusions:The time-course data of TGF-β1 and R-Smads indicate that progressive enhancement of TGF-β1 signalling via R-Smad is activated in the process of fibrosis progression.
Postglacial colonization and population genetic relationships in thePinus contortacomplex
Authors: Fazekas Aron J. , Yeh Francis C.
Published: June 2006

To explore the evolutionary relationships among the subspecies of lodgepole pine ( Pinus contorta Dougl. ex Loud.) and the possible existence of a northern glacial refugium for Pinus contorta Dougl. ex Loud. subsp. latifolia Engelm. and a coastal refugium for Pinus contorta Dougl. ex Loud. subsp. contorta , 31 populations were analyzed using RAPD markers to determine whether a pattern of isolation by distance exists. A total of 52 markers from 10 primers were scored. A significant pattern of isolation by distance was detected when all 31 populations were analyzed together and for the 19 populations of subsp. latifolia. A phylogenetic tree constructed from all 31 populations does not show an unambiguous division of the subspecies of P. contorta into distinct clades. Our results provide no support for the separation of lodgepole pine into various subspecies and show that the subspecies of lodgepole pine have not been sufficiently isolated from one another for a large amount of genetic divergence to occur between them. For subsp. latifolia, the pattern of isolation by distance is consistent with the hypothesis of a single refugium south of the glacial maximum with population expansion following glacial retreat. The amount of genetic distance and the pattern of differentiation in populations of subsp. contorta suggest a more complex history associated with fluctuation in ocean levels and glacial margins.
Rhizosphere-competent isolates of streptomycete and non-streptomycete actinomycetes capable of producing cell-wall-degrading enzymes to controlPythium aphanidermatumdamping-off disease of cucumber
Authors: El-Tarabily Khaled A.
Published: June 2006

Fifty-eight streptomycete and 35 non-streptomycete actinomycetes were isolated from cucumber rhizosphere soil. These isolates were screened for the production of cell-wall-degrading enzymes using mycelial ( Pythium aphanidermatum (Edson) Fitzp.) fragment agar. Eighteen promising isolates were screened for their competence as root colonizers. Eight isolates showing exceptional rhizosphere competence significantly inhibited, in vitro, P. aphanidermatum, the causal agent of postemergence damping-off of cucumber ( Cucumis sativus L.) seedlings. The four most inhibitory isolates ( Actinoplanes philippinensis Couch, Microbispora rosea Nonomura and Ohara, Micromonospora chalcea (Foulerton) Ørskov, and Streptomyces griseoloalbus (Kudrina) Pridham et al.) produced in vitro β-1,3-, β-1,4-, and β-1,6-glucanases and caused lysis of P. aphanidermatum hyphae. None of these produced volatile inhibitors or siderophores. Only S. griseoloalbus produced diffusible inhibitory metabolites, whilst A. philippinensis and Micromonospora chalcea parasitized the oospores of P. aphanidermatum. These four isolates were subsequently tested in the greenhouse, individually or as a mixture, for their ability to suppress damping-off of cucumber seedlings in soil with or without cellulose amendment. The treatment, which included all four isolates in soil amended with cellulose, was significantly superior to all other treatments in suppressing damping-off and was nearly as good as the metalaxyl treatment. Results show that there is a potential to use a mixture of antagonistic rhizosphere-competent actinomycetes along with cellulose amendment rather than fungicides for the field management of this disease. This is the first study that has involved the screening of rhizosphere-competent non-streptomycete actinomycetes capable of producing cell-wall-degrading enzymes, for the management of Pythium diseases.
Evolutionary relationships ofHyphodiscus hymeniophilus(anamorphCatenulifera rhodogena) inferred from β-tubulin and nuclear ribosomal DNA sequences
Authors: Untereiner Wendy A. , Naveau Françoise A. , Bachewich Jason , Angus Andrea
Published: June 2006

During an investigation of lignicolous ascomycetes from Luxembourg, we isolated a Phialophora -like species that produced striking red colonies. To confirm the identity of this fungus as Catenulifera rhodogena , we compared it with isolates of Catenulifera rhodogena and Hyphodiscus hymeniophilus on a variety of media. Portions of the β-tubulin gene and the nuclear ribosomal DNA cistron (internal transcribed spacers (ITS) and large subunit (LSU)) were sequenced to examine the relationship of isolates of Catenulifera rhodogena and Hyphodiscus hymeniophilus from different substrates and to test the hypothesis that Cadophora and Catenulifera are congeneric. The phylogenetic position of Catenulifera within the Ascomycota was investigated based on the analysis of the small-subunit (SSU) rDNA sequences. The isolates examined were indistinguishable micromorphologically and closely related phylogenetically. Three strains of Catenulifera rhodogena from bark or wood and one strain from Piptoporus betulinus formed a strongly supported clade in analyses of β-tubulin and ITS sequences. This clade did not encompass the ex-type isolates of Cistella rubescens and Scopulariopsis rhodogena or a second isolate of Catenulifera rhodogena from Piptoporus betulinus. Analysis of partial LSU sequences confirmed the close phylogenetic relationship of Catenulifera rhodogena and Hyphodiscus hymeniophilus but provided no evidence that the isolates could be grouped by substrate or that Catenulifera is synonymous with Cadophora. The position of Catenulifera within the Helotiales was not resolved based on the comparison of LSU and SSU sequences, but the isolate for which we obtained complete SSU sequence grouped with the root endophyte Phialocephala fortinii. Comparison of ITS sequences confirmed the close phylogenetic relationship of Hyphodiscus to members of the Dermateaceae and Hyaloscyphaceae.
Genetic variation of Populus tremuloides in ecophysiological responses to CO2 elevation
Authors: Liu Ning , Dang Qing-Lai , Parker William H.
Published: June 2006

To investigate the genetic variation of trembling aspen ( Populus tremuloides Michx.) in ecophysiological responses to [CO2] elevation, 1-year-old seedlings of four provenances (three families per provenance) from northwestern Ontario were exposed to three [CO2] levels in the greenhouse: ambient (360 ppm), 1.5 × ambient (540 ppm), and 2 × ambient (720 ppm). Biomass and foliage gas exchange were examined after 60 d of treatment. [CO2] elevation significantly increased the rate of net CO2 assimilation and photosynthetic water use efficiency. The stimulation was generally greater in the 540 ppm [CO2] than in 720 ppm [CO2]. The 720 ppm [CO2] resulted in a 10% photosynthetic down-regulation, but no down-regulation was detected in the 540 ppm CO2 treatment. The 540 ppm [CO2] (but not the 720 ppm) treatment significantly decreased stomatal conductance and transpiration rate in the provenances from the Great Lakes – St. Lawrence Region but not in those from the Boreal Region. The intercellular to ambient CO2 concentration ratio (Ci/Ca) was significantly higher under 720 ppm [CO2] than under the other two [CO2]. The CO2 elevations generally increased the total and root biomass, and the stimulation was greater in the 540 ppm [CO2] than in the 720 ppm [CO2] treatment. The two provenances from the Great Lakes – St. Lawrence region generally had greater biomasses than those from the boreal region, while there were no significant differences between them in the physiological variables. However, we did not find any significant differences between provenances in the responses of biomass to [CO2] treatments.
Réponses d’une vigne locale à une pollution fluorée
Authors: Ben Abdallah Ferjani , Elloumi Nada , Mezghani Imed , Boukhris Makki , Garrec Jean Pierre
Published: June 2006

Les effets d’une pollution atmosphérique par des composés fluorés ont été étudiés sur des cultivars d’une vigne locale, Vitis vinifera L. ‘Asli’, cultivée aux environs d'une usine de production d'engrais phosphatés. L’étude a pour objectif de déterminer les mécanismes permettant à ces vignes autochtones de survivre dans la zone polluée. Elle a consisté à suivre le comportement de ces cultivars dans deux parcelles : l’une soumise aux fumées d’une usine polluante et l’autre au loin de toute pollution. Les paramètres mesurés sont la conductance stomatique, la teneur des feuilles en F– et en Ca2+ et l’activité photosynthétique des zones foliaires saines. Nos résultats suggèrent que la survie de la vigne est liée à une compartimentation du fluor dans les bordures et les extrémités des feuilles, avec une tendance de la plante à contourner les nouveaux tissus nécrosés par un liseré de transition conduisant au développement d’auréoles concentriques de zones nécrosées donnant au limbe un aspect de mosaïque. Ce dernier peut donner des informations intéressantes sur la qualité de l’air et l’état des plantes. Ce comportement est concomitant à une aptitude des zones foliaires saines à conserver la capacité photosynthétique de la plante, tant que les nécroses ne dépassent pas 10 % à 20 % de la surface foliaire. Outre le piégeage du fluor dans des régions foliaires particulières, la fermeture temporaire des stomates semble également contribuer à la restriction de l’accumulation de ce polluant. Par ailleurs, le parallélisme entre l’accumulation du fluor et celle du calcium suggère que ce cation est impliqué dans le piégeage et la détoxication du fluor en le séquestrant sous forme de CaF2. Enfin, nos résultats ne plaident pas en faveur d’une remobilisation foliaire du fluor qui demeure séquestré dans les feuilles les plus âgées. D’ailleurs, la contamination des baies semble se faire directement par les fumées de l'usine, et non par apports endogènes.
Temporal variation of pollination classes in a tropical Venezuelan plain: the importance of habitats and life forms
Authors: Ramírez Nelson
Published: June 2006

Pollination of a total of 155 plant species was evaluated monthly in relation to flowering phenology, habitats, and life forms in the Venezuelan Central Plain. The relationships between flowering phenology and pollinating agent classes and their abundance were evaluated. The total number of pollinating agent classes was significantly correlated with the number of plant species for habitats and life forms, and at the community level. The number of pollinating agent classes did not change statistically with respect to flowering phenology for life form, habitats, and overall community, but the number of pollinting agent classes increased from the dry season to the rainy season for overall community and habitats, except for forest. The abundance of pollinating agents was significantly affected by flowering time. A cluster analysis revealed that the abundance of pollinating agent classes differed throughout the year, separating the dry and rainy seasons. Two trends were found in the temporal pattern of the nine pollinating agents: (1) nonseasonal, in which flowering of bat- and bird-pollinated species did not change drastically throughout the year; and (2) seasonal, in which the number of bee-, butterfly-, fly-, wasp-, moth-, beetle-, and wind-pollinated species changed throughout the year, increasing from the dry to the rainy season at the community level. The number of pollinating bees, butterflies, flies, and wasps peaked during the dry season for trees and shrubs, and therefore for forest. The number of moth-pollinated species increased from the mid-dry season to the rainy season, with a peak during the dry–rainy transition period. Beetle- and wind-pollinated species are phenologically concentrated in the rainy season: beetle-pollinated species were mainly in the forest and forest–savanna transition, and wind-pollinated species were associated with herbaceous species in savanna and disturbed areas. The distribution of pollinating agents was affected by seasonality in habitats and life forms. Therefore, life form may be considered a proximate element, reducing interference in the pollination process at the community level.
Phylogenetic relationships within Cicuta (Apiaceae tribe Oenantheae) inferred from nuclear rDNA ITS and cpDNA sequence data
Authors: Lee Chang-Shook , Downie Stephen R.
Published: June 2006

The genus Cicuta (Apiaceae tribe Oenantheae Dumort.) is the most virulently poisonous group of flowering plants native to the north temperate zone. A recent treatment recognized four species ( C. bulbifera L., C. douglasii (DC.) J.M. Coult. & Rose, C. maculata L., and C. virosa L.), with C. maculata divided into four varieties. We present results of phylogenetic analyses of the nuclear ribosomal DNA (rDNA) internal transcribed spacer (ITS) locus and the region bounded by the chloroplast genes psbI and trnK 5′ exon to determine taxonomic limits and relationships among these taxa, and to assess the taxonomic status of C. douglasii, a polyploid thought to be derived from C. maculata and C. virosa. Cicuta bulbifera and C. virosa are each resolved as monophyletic, the latter is a sister group to all other species. Discordance between the ITS- and plastid-derived phylogenies and lack of resolution in the ITS trees preclude unequivocal hypotheses of relationship; all trees do suggest, however, that the allotetraploid C. douglasii is polyphyletic and possibly polytopic, with all examined accessions but one nested within C. maculata. This single outstanding accession is from California and, pending further study, might warrant recognition as a distinct species. The diploid C. bulbifera may also be of hybrid origin, as revealed by significant discordance between data sets. Within C. maculata, only the western North American var. angustifolia Hook. is resolved in the ITS trees. In the cpDNA trees, C. maculata var. angustifolia comprises a strongly supported clade with C. maculata var. bolanderi (S. Watson) G.A. Mulligan and C. douglasii, both of primarily western North American distribution. The eastern North American taxa, C. maculata vars. maculata and victorinii (Fernald) B. Boivin, also comprise a clade, sister group to C. bulbifera.
Mapping subtle structures with light detection and ranging (LIDAR): flow units and phreatomagmatic rootless cones in the North Mountain Basalt, Nova Scotia
Authors: Webster Tim L , Murphy J Brendan , Gosse John C
Published: June 2006

Light detection and ranging (LIDAR) is an emerging technology to generate high-resolution digital elevation models (DEMs). Subtle topographical differences among three flow units of the Jurassic North Mountain Basalt, eastern Canada, are visible on a LIDAR-derived DEM. The boundaries were verified by field mapping and allow a simple projection of the contact planes through the terrain model to provide a three-dimensional visualization of the flow units. Several ring structures in the lower flow unit, distinguishable only in the LIDAR data, are interpreted to be the remnants of rootless phreatomagmatic cones. Glacial erosion has since excavated the highly fractured cone material, leaving the more resistant dike and quenched melt to form protruding ring structures. The ability to detect subtle variations in topography using LIDAR may identify previously undetected landscape elements.
A reappraisal of the tectonic significance of early Tertiary low-angle shear zones exposed in the Vernon map area (82 L), Shuswap metamorphic complex, southeastern Canadian Cordillera
Authors: Glombick P , Thompson R I , Erdmer P , Daughtry K L
Published: June 2006

Detailed geological mapping across the Shuswap metamorphic complex between latitudes 50°00′N and 50°45′N reveals that superstructure forms a semicontinuous carapace across the complex, with minimal evidence of internal thinning. Near the western margin of the complex, superstructure and infrastructure are juxtaposed across low-angle, ~2 km thick, ductile shear zones spatially associated with Paleocene to Early Eocene syn-kinematic granitic rocks. The shear zones, which yield upper plate to the west shear-sense indicators, are interpreted as the northern extension of the Okanagan Valley fault. Farther east, near the northsouth axis of the complex, superstructure and infrastructure are separated by an attenuated metamorphic section, but evidence of noncoaxial strain is lacking. Discrete detachments were not found. Steeply dipping normal faults cut low-angle shear zones and do not merge with them at depth. Middle Eocene volcanic and sedimentary rocks rest unconformably on metamorphic basement. The continuity of superstructure indicates that infrastructure was not exhumed by crustal-scale detachments. The results provide the basis for a complete reinterpretation of the tectonic significance of low-angle shear zones exposed in the Vernon area. It is proposed that Late Cretaceous to early Tertiary partial melting of the middle crust resulted in the development of a zone of channel flow. As the channel was underthrust by a crustal-scale ramp in underlying, more competent Paleo proterozoic basement, it was exhumed from depths of 2030 km and thinned vertically. Shear zones between infrastructure and superstructure are interpreted as being a transient rheological interface at the upper boundary of the channel.
Reservoir-induced earthquakes at Sainte-Marguerite-3, Quebec, Canada
Authors: Lamontagne Maurice , Hammamji Yousef , Tournier Jean-Pierre , Woodgold Catherine
Published: June 2006

Located some 90 km north of the town of Sept-Îles, Quebec, the Sainte-Marguerite-3 (SM-3) hydroelectric project was one of the most ambitious in eastern North America in recent years. The project included the construction of a 171 m high dam that created a 140 km long reservoir, some 120 m deep near the dam toe. Although the reservoir is located in a weakly seismic area of the Canadian Shield, reservoir-induced earthquakes occurred. A first event (mN1.3) was recorded in September 1999, ~17 months after the reservoir started filling. Between October 2000 and March 2001, four additional events were detected by the Canadian National Seismograph Network, the largest being mN1.7. During a field survey that took place between July and October 2001, 276 events of magnitude mN≤ 1.2 were detected within 30 km of a three-component seismograph. Single-station locations, confirmed by agreement between P phase and S phase azimuths, were determined for 182 events. Most earthquakes fall in four areas with estimated focal depths mostly shallower than 2 km. Since the field survey completion, more events have taken place, but the largest one is mN2.2 as of March 2006. This paper presents a detailed analysis of the reservoir-triggered events, together with a summary of seismic hazard evaluation of the dam site, the seismic parameters selected for dynamic analysis, and the selection of the design earthquake.
Early Paleozoic development of the Maine-Quebec Boundary Mountains region
Authors: Gerbi C C , Johnson S E , Aleinikoff J N , Bédard J H , Dunning G R , Fanning C M
Published: June 2006

Pre-Silurian bedrock units played key roles in the early Paleozoic history of the MaineQuebec Appalachians. These units represent peri-Laurentian material whose collision with the craton deformed the Neoproteozoic passive margin and initiated the Appalachian mountain-building cycle. We present new field, petrological, geochronological, and geochemical data to support the following interpretations related to these units. (1) The Boil Mountain Complex and Jim Pond Formation do not represent part of a coherent ophiolite. (2) Gabbro and tonalite of the Boil Mountain Complex intruded the Chain Lakes massif at ca. 477 Ma. (3) The Skinner pluton, an arc-related granodiorite, intruded the Chain Lakes massif at ca. 472 Ma. (4) The Attean pluton, with a reconfirmed age of ca. 443 Ma, is unrelated to Early Ordovician orogenesis. (5) The most likely timing for the juxtaposition of the Jim Pond Formation and the Boil Mountain Complex was during regional Devonian deformation. These interpretations suggest that the Boundary Mountains were once part of a series of arcs extending at least from central New England through Newfoundland.
Geochemical evidence for the origin of late Quaternary loess in central Alaska
Authors: Muhs Daniel R , Budahn James R
Published: June 2006

Loess is extensive in central Alaska, but there are uncertainties about its source and the direction of paleo winds that deposited it. Both northerly and southerly winds have been inferred. The most likely sources of loess are the Tanana River (south), the Nenana River (southeast), and the Yukon River (north). Late Quaternary loess in central Alaska has immobile trace-element compositions (Cr/Sc, Th/Ta, Th/Sc, Th/U, Eu/Eu*, GdN/YbN) that indicate derivation mostly from the Tanana River. However, other ratios (As/Sb, Zr/Hf, LaN/YbN) and quantitative modeling indicate that the Yukon River was also a source. During the last glacial period, there may have been a longer residence time of the Siberian and Canadian high-pressure cells, along with a strengthened Aleutian low-pressure cell. This would have generated regional-scale northeasterly winds and explains derivation of loess from the Yukon River. However, superimposed upon this synoptic-scale circulation, there may have been strong, southerly katabatic winds from expanded glaciers on the northern flank of the Alaska Range. These winds could have provided eolian silt from the Tanana River. Yukon River and Tanana River sediments are highly calcareous, whereas Fairbanks-area loess is not. This suggests that carbonate leaching in loess kept ahead of sedimentation and that late Quaternary loess in central Alaska was deposited relatively slowly.
The West Indian Road pit, central Nova Scotia: key to the Early Cretaceous Chaswood Formation
Authors: Gobeil Jean-Philippe , Pe-Piper Georgia , Piper David JW
Published: June 2006

The West Indian Road pit is the only large outcrop in Nova Scotia of the Chaswood Formation, the terrestrial equivalent of the offshore Missisauga and Logan Canyon formations. It provides outcrop information on sedimentology, gravel petrology, and structures for a formation that is otherwise known from a few small overgrown pits and from boreholes. The Chaswood Formation in the pit is > 60 m thick and consists principally of sorted sand and gravel with three thinner clay units. Successions of sedimentary structures indicate deposition from a coarse-bedload river flowing to the east-southeast. Gravel consists principally of vein quartz, quartz arenite, and subarkose, together with minor igneous lithologies that can be matched to sources in the Cobequid Highlands to the north. Quartz arenite and subarkose appear derived from Carboniferous Horton Group. Single-crystal 40Ar/39Ar dates of detrital muscovite are a little older than the muscovite ages for the South Mountain batholith, interpreted to mean that the muscovite is second cycle from the Horton Group, which records the earliest unroofing of the batholith. The Chaswood Formation accumulated during progressive tectonic deformation along NNE-trending strike-slip faults in basement rocks, resulting in syn-sedimentary faulting and local unconformities. Sedimentation kept pace with the creation of accommodation. Unrelated younger deformation folded the Chaswood Formation at the pit into an eastwest-trending syncline. The Early Cretaceous paleogeography of the Maritime Provinces is interpreted to have consisted of fault-bound horsts shedding coarse detritus surrounded by an interconnected series of basins that accumulated fluvial sands and gravels and overbank muds with well-developed paleosols.
Semi-local extraction of ring structures in images of biological hard tissues: application to the Bayesian interpretation of fish otoliths for age and growth estimation
Authors: Fablet Ronan
Published: June 2006

This paper deals with the analysis of images of biological tissue that involves ring structures, such as tree trunks, bivalve seashells, or fish otoliths, with a view to automating the acquisition of age and growth data. A bottom-up template-based scheme extracts meaningful ridge and valley curve data using growth-adapted time-frequency filtering. Age and growth estimation is then stated as the Bayesian selection of a subset of ring curves, which combines a measure of curve significativity and an a priori statistical growth model. Experiments on real samples demonstrate the efficiency of the proposed data extraction stage. Our Bayesian framework is shown to significantly outperform previous methods for the interpretation of a data set of 200 plaice otoliths and compares favorably with interexpert agreement rates (88% of agreement to expert interpretations).
Seasonal effects of the zebra mussel (Dreissena polymorpha) on sediment denitrification rates in Pool 8 of the Upper Mississippi River
Authors: Bruesewitz Denise A , Tank Jennifer L , Bernot Melody J , Richardson William B , Strauss Eric A
Published: June 2006

Zebra mussels (Dreissena polymorpha) have altered the structure of invaded ecosystems and exhibit characteristics that suggest they may influence ecosystem processes such as nitrogen (N) cycling. We measured denitrification rates seasonally on sediments underlying zebra mussel beds collected from the impounded zone of Navigation Pool 8 of the Upper Mississippi River. Denitrification assays were amended with nutrients to characterize variation in nutrient limitation of denitrification in the presence or absence of zebra mussels. Denitrification rates at zebra mussel sites were high relative to sites without zebra mussels in February 2004 (repeated measures analysis of variance (RM ANOVA), p = 0.005), potentially because of high NO3-N variability from nitrification of high NH4+zebra mussel waste. Denitrification rates were highest in June 2003 (RM ANOVA, p < 0.001), corresponding with the highest NO3-N concentrations during the study (linear regression, R2 = 0.72, p < 0.001). Denitrification was always N-limited, but sites without zebra mussels showed the strongest response to N amendments relative to sites with zebra mussels (two-way ANOVA, p ≤ 0.01). Examining how zebra mussels influence denitrification rates will aid in developing a more complete understanding of the impact of zebra mussels and more effective management strategies of eutrophic waters.
Modelling the spatial demography of Atlantic cod (Gadus morhua) on the European continental shelf
Authors: Andrews Jessica M , Gurney William SC , Heath Michael R , Gallego Alejandro , O'Brien Carl M , Darby Christopher , Tyldesley Graham
Published: June 2006

Atlantic cod (Gadus morhua) stocks across the North Atlantic have been subject to intense fishing pressure during the 20th century, and some stocks have suffered well-documented collapses. On the European shelf, cod are widely but heterogeneously distributed and are caught as part of a multispecies trawl fishery. There is a growing body of evidence that this stock is composed of substocks with potentially distinct demographic properties. As a first step towards the development of management methodologies that reflect this spatial and biological complexity, we present a spatially and physiologically explicit model describing the demography and distribution of cod on the European shelf. The computational efficiency of our implementation enables numerical parameter optimization, thus facilitating formal statistical tests of structural hypotheses. We use these methods to fit model variants embodying a variety of hypotheses about the movements of settled fish to a data set including spatial distribution information derived from International Bottom Trawl Surveys. The best-fit model emerging from this study is then used to investigate the potential effects of long-term application of a series of regional fishing closure policies.
Temperature-dependent growth of the blue crab (Callinectes sapidus): a molt process approach
Authors: Brylawski Bryce J , Miller Thomas J
Published: June 2006

Crustaceans display discrete and biphasic growth as a result of the molting process, so the traditionally used von Bertalanffy growth model does not capture well the phenomena associated with molting-based growth. A molt-process model can predict crustacean growth, including the temperature dependence of intermolt period that can produce the extended overwintering phenomena during which growth ceases. This study parameterized a molt-process model for the blue crab (Callinectes sapidus; Portunidae). Crab growth histories were observed for individual crabs held in field enclosures and temperature-controlled, recirculating tanks. A growth-based temperature of torpor (Tmin) of 10.8 °C was determined. A mean growth per molt of 119.5% increase in carapace width was observed. The average intermolt period observed was 536 ± 231 degree-days. The predictive ability of these growth parameter estimates was evaluated against growth observed in the field based on data on interannual changes in size frequencies of crabs from a winter dredge survey. The evaluated model was used to explore recruitment timing in warm (1996) and cold (1998) years. A 10% shift in the timing of juvenile crabs becoming available for legal exploitation was predicted from the simulations.
Gross primary production and respiration differences among littoral and pelagic habitats in northern Wisconsin lakes
Authors: Lauster George H , Hanson Paul C , Kratz Timothy K
Published: June 2006

Net ecosystem production (NEP) trends among lakes have been ascribed to differences in nutrient and allochthonous carbon inputs, but little is known on how different habitats within lakes contribute to these trends. We sampled pelagic and littoral surface waters using sonde (i.e., free-water) and bottle methods concurrently in lakes spanning a range of trophic conditions. We considered whether the typically higher metabolism estimates found with sonde methods are due to contributions from littoral habitats not reflected by bottle estimates. We sought the source of littoral contributions by selecting sites with maximum differences in macrophyte abundance. Sonde estimates for pelagic primary production and respiration were twothree times greater than bottle estimates. Sonde/bottle ratios were higher in productive lakes and lakes with more littoral area. Bottle estimates were similar among all sites, and sonde estimates in macrophyte-poor sites were similar to pelagic sondes. However, sonde estimates in macrophyte-rich areas were fournine times greater than bottle estimates. Results suggest littoral zones increase whole-lake NEP in eutrophic systems, whereas the Sphagnum mat surrounding dystrophic lakes decreases NEP. Non-planktonic organisms associated with macrophytes provide important littoral contributions to whole-lake metabolism and to understanding NEP trends among lakes.
Compensation ratios needed to offset timing effects of losses and gains and achieve no net loss of productive capacity of fish habitat
Authors: Minns Charles K
Published: June 2006

Minns' (Can. J. Fish. Aquat. Sci. 54: 24632473 (1997)) framework for assessing net change of productive capacity of fish habitats in Canada is expanded to include the effect of timing of losses and gains on cumulative net change. The expansion requires establishment of a reference time frame for assessment. A time frame of twice the project's duration is recommended. Delaying compensation actions while incurring losses early in a project increases the levels of compensation required. The addition of future discounting had much less effect on compensation requirements than the effects resulting from timing differences between losses and compensation. As discounts apply equally to losses and gains, they likely balance out over time. Delays between when habitat alterations occur and when expected productive capacity is attained increase the required compensation. There are advantages to starting compensation efforts early in a development project. A case study of a hypothetical northern diamond mine shows how various components of compensation (replacement, uncertainty, and timing) can be integrated when assessing net change. Consideration of all components of compensation indicates the need for tougher precautionary compensation guidelines with ratios greater than the current 1:1. Values of 2:1 or higher may be necessary to ensure attainment of Canada's guiding policy principle of no net loss.
Microsatellite DNA analysis of coastal populations of bull trout (Salvelinusconfluentus) in British Columbia: zoogeographic implications and its application to recreational fishery management
Authors: Taylor Eric B , Costello A B
Published: June 2006

Microsatellite DNA variation was assayed among 383 bull trout (Salvelinus confluentus) from 20 Pacific coastal localities from the Skeena River (central British Columbia) to the Olympic Peninsula (western Washington State). An average of 1.7 alleles was resolved per population and heterozygosity averaged 0.35. Twenty-six fish were identified as bull trout × Dolly Varden (Salvelinus malma) hybrids. Population subdivision was substantial (θ = 0.33), but subdivision was higher (θ = 0.46) when interior populations (N = 37) were included, indicating a major genetic distinction between "coastal" and "interior" bull trout. Bull trout populations north of the Squamish River were genetically more similar to interior bull trout than to other more southern coastal populations, suggesting that they had been founded by headwater transfers from interior populations. Individual assignment of bull trout averaged 53.4% correct assignment among populations (range: 12%95%). Mixture analysis indicated that most fish from the lower Fraser River recreational fishery originated from major nearby tributaries (e.g., Pitt, upper Lillooet, and Chilliwack rivers). Our results substantiate the existence of two major evolutionary lineages of bull trout and highlight the importance of tributary habitats for the persistence of local populations, as well as for those that forage in downstream areas on the lower Fraser River.
Effects of ontogeny, season, and temperature on the swimming performance of juvenile green sturgeon (Acipenser medirostris)
Authors: Allen Peter J , Hodge Brian , Werner Inge , Cech, Jr. Joseph J
Published: June 2006

Because some salmonids show decreased swimming performance (Ucrit) during their parr-smolt transformation, we tested the hypothesis that juvenile anadromous green sturgeon (Acipenser medirostris) decrease Ucritduring their analogous ontogenetic stage. Juvenile green sturgeon (mean age: 98 days) that had not reached seawater tolerance had a positive relationship of Ucrit(cm·s1) with total length (TL), whereas seawater-tolerant sturgeon (mean age: 150 days) had a negative relationship of Ucritwith TL. This Ucritdecrease was presumably seasonal because a similar-sized group of fish tested later (mean age: 288 days) showed a linear increase in Ucritwith TL. Smaller sturgeon displayed both morphological (larger relative pectoral fin surface areas) and behavioral (rostrum wedging and pectoral fin holding) attributes for station holding in a riverine environment. In a second experiment to test the effects of increased river temperature near the predicted time of downstream migration, Ucritand heat-shock protein concentrations increased at 24 °C compared with at 19 °C (mean age: 155 days). Thus, although there was evidence for cellular stress, the swimming ability of the fish was not compromised. Therefore, water velocity, temperature, and time of year should be considered in life-stage-specific efforts to manage or protect green sturgeon.
Contribution of commonly analyzed polycyclic aromatic hydrocarbons (PAHs) to potential toxicity in early life stages of rainbow trout (Oncorhynchus mykiss)
Authors: Sundberg Henrik , Ishaq Rasha , Tjärnlund Ulla , Åkerman Gun , Grunder Kerstin , Bandh Cecilia , Broman Dag , Balk Lennart
Published: June 2006

In a series of bio-effect-directed fractionation experiments, we investigated the potential toxicity of sediment extracts from a contaminated bay. A previous study investigated abnormalities and hepatic ethoxyresorufin O-deethylase (EROD) activities in rainbow trout (Oncorhynchus mykiss) larvae by exposing newly fertilized eggs to the total extract and to fractions separated by degree of aromaticity. A major part of the potential toxicity was isolated in a fraction containing polycyclic aromatic compounds (PACs). In this study, we prepared a synthetic PAC mixture with 17 commonly analyzed polycyclic aromatic hydrocarbons (PAHs) in amounts equimolar to those found in the sediment PAC fraction. The 17 PAHs, which included 11 of the 16 United States Environmental Protection Agency (US EPA) priority PAHs, were unable to account for the toxicopathic effects observed and could explain less than 4% of the total EROD induction. The lack of a clear relationship between toxicopathic effects and EROD induction underlines the need for a battery of biomarkers for estimating environmental risk. These results reveal the limits of our knowledge regarding compounds responsible for potential toxicity in field situations.
Threat and decline in fishes: an indicator of marine biodiversity
Authors: Dulvy Nicholas K , Jennings Simon , Rogers Stuart I , Maxwell David L
Published: June 2006

Recent policy commitments aim to reduce biodiversity loss and integrate environmental concerns into fisheries management. However, there are few operational indicators for reporting biodiversity trends and judging progress in relation to management objectives. Here we develop a threat indicator based on the population status of a suite of 23 North Sea fishes from 1982 to 2001 estimated using World Conservation Union (IUCN) Red List decline criteria. The composite indicator was calculated from the weighted average of the threat scores of individual species in each year and varies from 0 to 3, where a score of 3 is equivalent to each species qualifying as "critically endangered". The proportion of threatened fishes, their degree of threat, and the composite indicator value increased steadily over time. The composite indicator value has been >1 since the late 1990s, equivalent to all species meeting the "vulnerable" criterion. A suitable reference trajectory, consistent with the World Summit on Sustainable Development commitment to "achieve by 2010 a significant reduction of the current rate of biodiversity loss" would be a significant reduction in the rate of increase in this indicator before 2010, a limit reference point could be 1 (all species vulnerable) and a target reference point could be 0 (no threatened species).
A length-based multispecies model for evaluating community responses to fishing
Authors: Hall Stephen J , Collie Jeremy S , Duplisea Daniel E , Jennings Simon , Bravington Mark , Link Jason
Published: June 2006

Quantitative ecosystem indicators are needed to fulfill the mandate for ecosystem-based fisheries management. A variety of community metrics could potentially be used, but before reference levels for such indices can be established the sensitivity of candidate indices to fishing and other disturbances must be determined. One approach for obtaining such information is to test candidate indicators with models that mimic real ecosystems and can be manipulated experimentally. Here we construct a size-based multispecies model of a community of fish species that interact by predation. The model was parameterized for 21 fish species to obtain a predation-regulated community. Following an analysis of the sensitivity of the model to parameter uncertainty, we tested the sensitivity of community-level indicators to increasing levels of fishing mortality (F). Abundance and biomass spectra were sensitive to fishing mortality, with the slope decreasing with increasing F. Species diversity size spectra were also very sensitive to F, with diversity in the largest size classes declining rapidly. In contrast, k-dominance curves were less sensitive to fishing pressure. Importantly, however, although most community-level metrics showed clear trends in response to fishing, single-species declines in spawning stock biomass were the most sensitive indicators of fishing effects.
The impact of postglacial marine invasions on the genetic diversity of an obligate freshwater fish, the longnose dace (Rhinichthys cataractae), on the Quebec peninsula
Authors: Girard Philippe , Angers Bernard
Published: June 2006

Postglacial seas are expected to have had significant effects on the genetic structure of populations of obligate freshwater fishes. To assess this influence, mitochondrial DNA variability was evaluated in 32 populations of longnose dace (Rhinichthys cataractae) of the Quebec peninsula located within and outside of the maximum extent of marine invasions of the Champlain and Laflamme seas. Three clades of haplotypes diverging from one to two mutations were defined. Despite this low divergence, a clear and significant spatial genetic structure was observed outside of the extent of marine invasions. However, a higher genetic diversity was observed in populations located within the extent of marine invasions because of the admixture of these clades with an additional lineage restricted almost exclusively to those areas. The low genetic divergence between the main haplotypes suggests a single origin, despite the known presence of this species in various refuges. Marine invasions preventing entry to the peninsula, especially from Atlantic refuge, are proposed as a possible explanation to this particular result. This study is a relevant argument for integrating postglacial marine invasions into postglacial colonization models of freshwater species in the northeastern part of North America.
Attosecond science and technology
Authors: Levesque J , Corkum P B
Published: June 2006

Attosecond technology is a radical departure from all the optical (and collision) technology that preceded it. It merges optical and collision physics. The technology opens important problems in each area of science for study by previously unavailable methods. Underlying attosecond technology is a strong laser field. It extracts an electron from an atom or molecule near the crest of the field. The electron is pulled away from its parent ion, but is driven back after the field reverses. It can then recollide with its parent ion. Since the recolliding electron has a wavelength of about 1 Å, we can measure Angstrom spatial dimensions. Since the strong time-dependent field of the light pulse directs the electron with subcycle precision, we can control and measure attosecond phenomena. PACS Nos.: 33.15.Mt, 33.80.Rv, 39.90.+d, 42.50.Hz, 42.65.Ky