bluuebunny/crossref_metadata_2025 huggingface dataset:
Sex Composition, Masculinity Stereotype Dissimilarity and the Quality of Men's Workplace Social Relations
Authors: Bird Sharon R.
Published: October 2003

Previous research suggests that the quality of men's work group social relations varies depending on the sex composition of the work unit. Previous studies also suggest that men derive different benefits from working with other men than with women and that the higher status associated with men and masculinity advantages men in their relations with women workers. Previous sex composition studies tell us little, however, about the extent to which the quality of men's work group social relations with women and other men depends on how well a man fits dominant masculinity stereotypes. Drawing on sex composition and gender constructionist approaches to gender and work I investigate in this study the effects of men's individual similarity to masculinity stereotypes on the affective quality of their social relations with coworkers, given the sex composition of their work groups. The data for this study consist of male, mostly white, non‐faculty employees of a public university in the northwest United States. I discuss my results in terms of both individual outcomes and implications for understanding sex and gender inequalities in work organizations.
A Privileged Pole? Diversity in Women's Pay, Pensions and Wealth in Britain
Authors: Warren Tracey
Published: October 2003

Is gender on its own becoming redundant in the analysis of employment experiences? There is a growing interest in economic diversity amongst women within the social sciences, with commentators suggesting, firstly, that a polarization in women's labour market experiences is occurring. Secondly, economic diversity amongst women may even be so distinct that a privileged pole is faring substantially better in wage and occupational terms than most men. This article uses data from theFamily Resources Surveyto explore these two suggestions. It concludes that the success on the labour market that has been achieved by an economically privileged pole amongst women supports the decline in the power of gender to explain variation in occupational patterns and wages, but it is clear that gender (tempered with awareness of the ways that it is cross‐cut by class, ethnicity and other social divisions) remains an invaluable explanatory variable for our understanding of economic security in its fuller sense, not least in the pension positions of women.
Moving forward with chemical mutagenesis in the mouse
Authors: O'Brien Timothy P. , Frankel Wayne N.
Published: October 2003

The study of genetic variation in mice offers a powerful experimental platform for understanding gene function. Complex trait analysis, gene‐targeting and gene‐trapping technologies, as well as insertional and chemical mutagenesis approaches are becoming increasingly sophisticated and provide a variety of options for cataloguing gene activities and interactions. In this review we discuss fundamental and practical concepts related to chemical mutagenesis and we highlight the growing list of strategies for performing mutagenesis screens in mice. Gene‐driven and diverse types of phenotype‐driven screens provide several options for the recovery of the invaluable variety of alleles generated by chemical mutagenesis. The unique advantages offered using chemical mutagenesis compare favourably to and complement the spectrum of approaches available for functional annotation of the mammalian genome.
Activity of dorsal raphe cells across the sleep–waking cycle and during cataplexy in narcoleptic dogs
Authors: Wu M.‐F. , John J. , Boehmer L. N. , Yau D. , Nguyen G. B. , Siegel J. M.
Published: October 2003

Cataplexy, a symptom associated with narcolepsy, represents a unique dissociation of behavioural states. During cataplectic attacks, awareness of the environment is maintained, as in waking, but muscle tone is lost, as in REM sleep. We have previously reported that, in the narcoleptic dog, noradrenergic cells of the locus coeruleus cease discharge during cataplexy. In the current study, we report on the activity of serotonergic cells of the dorsal raphe nucleus. The discharge patterns of serotonergic dorsal raphe cells across sleep–waking states did not differ from those of dorsal raphe and locus coeruleus cells recorded in normal rats, cats and monkeys, with tonic discharge in waking, reduced activity in non‐REM sleep and cessation of activity in REM sleep. However, in contrast with locus coeruleus cells, dorsal raphe REM sleep‐off neurones did not cease discharge during cataplexy. Instead, discharge continued at a level significantly higher than that seen in REM sleep and comparable to that seen in non‐REM sleep. We also identified several cells in the dorsal raphe whose pattern of activity was the opposite of that of the presumed serotonergic cells. These cells were maximally active in REM sleep and minimally active in waking and increased activity during cataplexy. The difference between noradrenergic and serotonergic cell discharge profiles in cataplexy suggests different roles for these cell groups in the normal regulation of environmental awareness and muscle tone and in the pathophysiology of narcolepsy.
Pacing‐induced calcineurin activation controls cardiac Ca2+ signalling and gene expression
Authors: Tavi Pasi , Pikkarainen Sampsa , Ronkainen Jarkko , Niemelä Perttu , Ilves Mika , Weckström Matti , Vuolteenaho Olli , Bruton Joseph , Westerblad Håkan , Ruskoaho Heikki
Published: October 2003

Calcineurin, a Ca2+–calmodulin‐dependent protein phosphatase (PP2B) is one of the links between Ca2+ signals and regulation of gene transcription in cardiac muscle. We studied the Ca2+ signal specificity of calcineurin activation experimentally and with modelling. In the rat atrial preparation, an increase in pacing frequency increased nuclear activity of the calcineurin‐sensitive transcription factor, nuclear factor of activated T‐cells (NFAT), 2‐fold in a cyclosporin A (CsA)‐sensitive manner. In line with this, modelling results predicted that the frequency of cardiac Ca2+ transients encodes the stimulus for calcineurin activation. We further observed experimentally that calcineurin inhibition by CsA modulated Ca2+ release in a Ca2+‐dependent manner. CsA had no effect on [Ca2+]i at a pacing frequency of 1 Hz but it significantly suppressed the amplitude of Ca2+ transients, systolic [Ca2+]i and time averaged [Ca2+]i at 6 Hz. Calcineurin had a differential role in the expression of immediate‐early genes B‐type natriuretic peptide (BNP) and c‐fos. CsA inhibited the pacing‐induced BNP gene expression, whereas pacing alone had no effect on the expression of c‐fos. However, in the presence of CsA, c‐fos mRNA levels were significantly augmented by increased pacing frequency. These results show that frequency‐dependent calcineurin activation has a specific role in [Ca2+]i regulation and gene expression, constantly recruited by varying cardiac Ca2+ signals.
Nanosized Molecular Sieves
Authors: Mintova Svetlana
Published: October 2003

Nanosized molecular sieves or colloidal zeolites are crystalline porous solids with particle sizes in the range of 10-1000 nm; they are synthesized from colloidal precursor solutions under hydrothermal conditions at temperatures lower than 100 °C. The complex mechanism by which nanosized microporous materials are assembling from framework constituent precursor species under heating is investigated by in situ dynamic light scattering, X-ray diffraction using synchrotron radiation, high resolution transmission electron microscopy, and IR/Raman spectroscopies. The development of new crystallization methods that allow the fabrication of zeolites in forms suitable for practical utilization, such as thin films, layers, and monoliths based on the seed method and spin coating approach is discussed. In situ X-ray measurements of zeolite crystal growth simultaneously in solutions and films are performed, in which near surface depth-sensitive grazing incidence diffraction is combined with the in situ growth of thin zeolite films that is ideally suited to shed light on the unresolved mechanisms of self-organized channel orientation for various zeolite systems. In addition, the nanosized Faujasite (FAU) zeolite was employed as host for the stabilization of guest molecules such as 2-(2'-hydroxyphenyl)benzothiazole (HBT); the trans keto tautomer of HBT inside the FAU zeolite is demonstrated and compared with the cis keto tautomer formed in ethanolic solution.
Dioécie cryptique chez Geniostoma borbonica, espèce pionnière endémique de La Réunion
Authors: Humeau Laurence , Strasberg Dominique , Pailler Thierry
Published: October 2003

In the general context of conservation of insular habitats, the floral biology, natural fecundity, and breeding system of Geniostoma borbonica (Lam.) Spreng. was studied in natural populations. The species, which was initially assumed to be gynodioecious, presents two kinds of individuals, both with morphological hermaphroditic but functionally unisexual flowers. Some individuals produce pollen grains, but neither ovules nor fruit, whereas other fructiferous individuals have anthers without pollen grains. Geniostoma borbonica is the first species in this genus to be reported as dioecious; its floral morphology illustrates an example of cryptic dioecy. This species combines an apomictic breeding system, assuring a fast installation without reproductive constraints, and a reproductive breeding system assuring maintenance of genetic variability in the population. These two breeding systems allow adaptation to evolution of the habitat during plant succession. This point is discussed in the colonization context of pioneer habitats, where herma- phro ditic species are recognized to be advantageous, as well as in the context of the evolution of dioecy in this genus.Key words: cryptic dioecy, pioneer habitat, oceanic island, Geniostoma.
Morphological and molecular data to determine the origin and taxonomic status ofProsopis chilensisvar.riojana(Fabaceae, Mimosoideae)
Authors: Vázquez-Garcidueñas Soledad , Palacios Ramón A , Segovia-Quiroz Jenny , Frías-Hernández Juan T , Olalde-Portugal Victor , Vega Octavio Martínez-de la , Mollard F P.O , Vázquez-Marrufo Gerardo
Published: October 2003

This study analyzes the morphological and genetic characteristics of three sympatric populations of Prosopis from Argentina. Although morphological and geographical data suggest that Prosopis chilensis var. riojana is an interspecific hybrid of Prosopis chilensis var. chilensis and Prosopis flexuosa var. flexuosa, no correlation was found between morphological traits and genetic distances generated by random amplified polymorphic DNA - polymerase chain reaction (RAPD-PCR). Genetic similarity is greater among P. chilensis var. chilensis and P. flexuosa var. flexuosa than between either of these two taxa with P. chilensis var. riojana. Also, P. chilensis var. riojana has unique genetic markers that are absent from its putative parents. Additionally, dendrograms generated by unweighted pair group method with arithmetic means (UPGMA) and Neighbor-Joining clustering criteria group P. chilensis var. chilensis and P. flexuosa var. flexuosa apart from P. chilensis var. riojana. Possibilities for the lack of congruence between morphology and RAPD markers are discussed. The results obtained are insufficient to conclusively establish the origin of P. chilensis var. riojana; however, the morphological and genetic traits observed suggest this taxon is well differentiated from P. chilensis var. chilensis and P. flexuosa var. flexuosa.Key words: genetic distances, hybridization, morphology, Prosopis, RAPD, rare taxon.
Identifying pollen grains ofTypha latifolia, Typha angustifolia,andTypha×glauca
Authors: Finkelstein Sarah A
Published: October 2003

Typha angustifolia L. and Typha ×glauca Godron have increased their ranges on the North American continent over the past 150 years, and the pollen record has potential to document this spread. In T. angustifolia, pollen disperses as a reticulate, monoporate monad, similar in appearance to the pollen of Sparganium eurycarpum Engelm. Typha angustifolia and Sparganium are generally not distinguished, and T. ×glauca is rarely shown on pollen diagrams. My study of pollen reference material shows that Typha monads and Sparganium can be separated using diameter and roundness at a known level of statistical confidence. Typha monads are on average significantly smaller in diameter (mean and standard deviation = 22.7 ± 2.6 µm) than Sparganium (25.3 ± 2.7 µm). The incidence of angularity is higher in T. angusti folia pollen grains, whereas Sparganium grains are more often rounded. The pollen signature of T. ×glauca consists of mostly monads, but can contain up to 30% dyads, and (or) 14% tetrads, and (or) 10% triads. I suggest that T. angusti folia and T. ×glauca can be identified as one category in the pollen record and, where their dates of arrival are known, this category may be used as a chronostratigraphic indicator.Key words: Typha, Sparganium, pollen, invasive species, wetlands.
Incorporation of [3H]sucrose after the resorption of nectar from the spur of Platanthera chlorantha (Custer) Rchb.
Authors: Stpiczynska Malgorzata
Published: October 2003

Platanthera chlorantha (Custer) Rchb., a moth-pollinated orchid, secretes abundant nectar. Sucrose incorporation following the resorption of nectar from the spurs of the pollinated and unpollinated flowers of P. chlorantha was investigated. The study was carried out using 3H-labelled sucrose and microautoradiography. In this orchid species, nectar was secreted and accumulated in the spur. Inside the spur, the epidermis developed numerous unicellular secretory hairs engaged in nectar secretion and resorption. Nectar resorption occurred near the end of anthesis. Following pollination, sucrose from the resorbed nectar was incorporated into starch accumulated in parenchyma cells of developing capsules. Additionally, radioactivity in the cell walls of parenchyma and ovules was also observed. The label was not detected either in the gynoecium of unpollinated flowers or in tuberous roots of all plants investigated. Therefore, the results demonstrate that carbohydrates reclaimed from uncollected nectar in pollinated flowers of P. chlorantha are next utilized inside the adjacent maturing fruits.Key words: Platanthera chlorantha, Orchidaceae, nectar resorption, nectary spur, microautoradiography, pollination.
Germination response of dimorphic seeds of two halophyte species to environmentally controlled and natural conditions
Authors: Carter Christy T , Ungar Irwin A
Published: October 2003

To determine whether or not tolerance limits at the germination stage of development and annual germination patterns affect plant distribution in an inland salt marsh, we assessed germination of dimorphic seeds for Atriplex prostrata Boucher ex DC. and Salicornia europaea L. under field and laboratory conditions. Statistically significant differences were found in germination across marsh zones for both species in the field. However, germination percentages for small seeds of A. prostrata and S. europaea were above 50% and 75%, respectively, across all zones for seeds placed on the surface. For large seeds of each species placed on the surface, germination was above 90% across all zones. Small seeds for both species had primary dormancy, a light requirement for germination, and appeared to exhibit dormancy cycling. Large seeds of A. prostrata were nondormant from December through March, whereas large seeds of S. europaea were nondormant when produced. Persistent seed banks were most likely to be formed from small seeds of both species. Seeds typically germinate in the spring when salinity across the marsh is sufficiently low for seeds to germinate in all zones, indicating that the germination stage of development does not effect the spatial distribution of A. prostrata or S. europaea on the marsh.Key words: Atriplex prostrata, seed dormancy and germination, halophyte, Salicornia europaea, seed dimorphism, salt marsh zonation.
Intraspecific variability in Commelina erecta : response to phosphorus addition
Authors: Urich R , Coronel I , Silva D , Cuberos M , Wulff R D
Published: October 2003

To examine intraspecific variability, we studied the biomass production and physiological responses of clonal replicates of the widespread perennial herb Commelina erecta L. grown under different phosphorus concentrations. Five replicates per genotype collected from a small population were exposed to 0.01 or 1.0 mmol·L1 phosphate in a hydroponic solution and grown under natural radiation. High intraspecific variability occurred for ecologically important traits such as root, leaf, and total plant biomass, with significantly higher responses in the high phosphorus treatment. The norms of reaction for high versus low phosphorus supply often crossed, indicating that selection for different genotypes may be enhanced in some environments and reduced in others. The root phosphorus concentration and phosphorus absorption rate varied among clones. Phosphorus supply increased photosynthetic rates in all clones 15 days after the start of the experiment, but treatment differences were lost with development when significant clone variability was observed. Maximum photosynthetic rates and carboxylation efficiencies were different between clones and treatments; relative stomatal and mesophyll limitations to photosynthesis also varied among clones. Predawn photochemical efficiency remained relatively constant among treatments and clones. Commelina erecta showed a very high intraspecific variability, which is an important factor in plant survival and success.Key words: growth, norms of reaction, photosynthesis, phosphorus absorption.
Leaf epidermal characteristics of Lotus subgenus Acmispon (Fabaceae: Loteae) and a numerical taxonomic evaluation
Authors: Stenglein Sebastián A , Arambarri Ana M , Colares Marta N , Novoa María C , Vizcaíno Claudia E
Published: October 2003

This paper describes the leaf epidermal characteristics of the New World species of Lotus L. subgenus Acmispon Raf. (Fabaceae: Loteae), computes their phenetic relationships based on morphological and anatomical characters, and compares these results with previous classifications and a recent phylogenetic hypothesis for the group based on morphological data. Leaves of 16 species of Acmispon were cleared and examined using light microscopy. Data on epidermal cells, stomata, stomatal index, and trichomes were described and summarized. To test the taxonomic value of epidermal characters and to ascertain phenetic relationships, we performed two numerical analyses using unweighted pair-group arithmetic average clustering. Results of the numerical analysis (16 operational taxonomic units (OTUs) × 13 epidermal characters) suggested that epidermal characteristics are insufficient to resolve sections Simpeteria and Microlotus. An additional analysis (16 OTUs × 23 characters) demonstrated that epidermal micro morphological features, together with other characters, are useful and informative for distinguishing these two sections. Results generated by the latter analysis accord well with earlier classifications and a previous phylogenetic hypothesis by showing that the sections Simpeteria and Microlotus are coincident with the two monophyletic subgroups Grandiflorus and Salsuginosus, respectively, inferred using cladistic analysis.Key words: Acmispon, epidermis, Fabaceae, Loteae, Lotus, Microlotus, Simpeteria.
Responses to a fluctuating environment: effects of water depth on growth and biomass allocation in Eleocharis cellulosa Torr. (Cyperaceae)
Authors: Edwards Adrienne L , Lee David W , Richards Jennifer H
Published: October 2003

Fluctuating water levels, which characterize freshwater marshes of the Florida Everglades, U.S.A., constrain growth in emergent macrophytes. We studied acclimation of Eleocharis cellulosa Torr. (Cyperaceae) in mesocosms to water depths of 7 and 54 cm and to switching between these water depths. After 80 weeks at fixed depths, deepwater plants produced (i) taller, thicker, and fewer shoots; (ii) fewer ramets; (iii) less biomass; and (iv) greater shoot biomass relative to root and rhizome biomass. Despite large differences in shoot lengths between water depths, shoot heights above the water surface were similar. Emergent shoot tissues had thick secondary walls in the epidermal cells and several palisade layers beneath; submerged shoots lacked this anatomy. When shallow-water plants were transferred to deep water, shoots elongated rapidly, with younger shoots elongating more than older ones. When deepwater plants were transferred to shallow water, emergent shoots quickly died and were replaced by new shoots. Overall, plants exposed to rapid changes in water level adjusted biomass allocation patterns after 9 weeks towards those of control plants in their new environment, but deepwater plants responded more slowly than shallow-water plants. These shifts may allow E. cellulosa to produce shoots that optimize biomechanical support and aeration.Key words: biomass allocation, Eleocharis cellulosa, Everglades, gas exchange, shoot demography, wetland plants.
Regrowth response of young black spruce (Picea mariana) trees to meristem removal and resource addition
Authors: Bast Marcy , Reader R J
Published: October 2003

Regrowth of an injured plant may exceed the growth of a noninjured plant (i.e., overcompensation) when (i) dormant meristems are available to replace injured meristems, (ii) the injury level is sufficient to release dormant meristems from apical dominance, and (iii) the supply of mineral nutrient and light is sufficient to support the outgrowth of previously dormant meristems. A field experiment was conducted with 5-year-old black spruce trees to determine whether these three conditions were met when 25%, 50%, or 75% of a tree's uppermost buds were removed. Subsequent shoot growth on treated and nontreated trees (0% meristem removal) was compared for each of two levels of resource supply (natural and enhanced). Enhanced levels of light and mineral nutrients were created by removing neighbouring plants within a 2-m radius of a target tree and adding 10 grams of NPK fertilizer per tree. After 5 and 17 months, shoot growth did not differ significantly among trees in the four meristem removal treatments (condition ii above), regardless of resource supply (condition iii above). The absence of overcompensation most likely reflects the relatively small supply of dormant meristems on treated trees (condition i above).Key words: apical meristem, black spruce, compensatory growth, injury.
Topography of the crustmantle interface under the Western Superior craton from gravity data
Authors: Nitescu B , Cruden A R , Bailey R C
Published: October 2003

The Moho undulations beneath the western part of the Archean Superior Province have been investigated with a three-dimensional gravity inversion algorithm for a single interface of constant density contrast. Inversion of the complete gravity data set produces unreal effects in the solution due to the ambiguity in the possible sources of some crustal gravity anomalies. To avoid these effects a censored gravity data set was used instead. The inversion results are consistent with reflection and refraction seismic data from the region and, therefore, provide a basis for the lateral correlation of the Moho topography between parallel seismic lines. The results indicate the existence of a major linear eastwest-trending rise of the Moho below the metasedimentary English River subprovince, which is paralleled by crustal roots below the granitegreenstone Uchi and Wabigoon subprovinces. This correlation between the subprovincial structure at the surface and deep Moho undulations suggests that the topography of the crustmantle boundary is related to the tectonic evolution of the Western Superior belts. Although certain features of the crustmantle boundary are likely inherited from the accretionary and collisional stages of the Western Superior craton, gravity-driven processes triggered by subsequent magmatism and crustal softening may have played a role in both the preservation of those features, as well as in the development of new ones.
New 42 Ma cratonic North American paleomagnetic pole from the Yukon underscores another Cordilleran paleomagnetism-geology conundrum
Authors: Symons David TA , Erdmer Philippe , McCausland Phil JA
Published: October 2003

Eocene posttectonic plutons of the Beaver River alkalic complex in southeastern Yukon intruded DevonianMississippian and Triassic sandstones in the Foothills of the Canadian Cordillera. A paleomagnetic collection of 27 sites from three separate plutons produced 326 specimens that were analyzed using alternating field and thermal step demagnetization methods. The A component characteristic remanent magnetization (ChRM) resides in magnetite with normal polarity in the 42.6 ± 0.8 Ma Beaver River pluton, reversed polarity in the 42.1 ± 0.7 Ma Larson Creek East pluton, and both polarities in the 41.3 ± 0.4 Ma Larson Creek West pluton, corresponding with magnetic polarity chrons 20n, 19r, and the boundary between chron 19r and 18n, respectively. The ChRMs of the plutons are indistinguishable (2σ) with a mean for the 42.0 ± 0.5 Ma complex of D = 158.8°, I = 73.1° (N = 21 sites, α95= 3.0°, k = 116.8). A positive paleomagnetic contact test shows the A component to be primary, and the poorly isolated B component suggests the host rocks for Larson Creek West are Early to Middle Devonian. The paleopole for the Beaver River complex at 79.2°N, 145.8°E (N = 21, dp = 4.8°, dm = 5.4°; Q = 7) is concordant with interpolated 42 Ma reference poles for the North American craton. In contrast, paleopoles from the accreted Intermontane and eastern Coast Belt terranes record clockwise rotations of 24° ± 10° (Eocene) and 13° ± 5° (OligocenePliocene), indicating that the allochthonous Intermontane terranes have been progressively driven ~240 ± 120 km eastwards up and over pericratonic and cratonic North American lower crust by Pacific plate subduction since the mid-Eocene.
Early Archean to Mesoproterozoic evolution of the Wyoming Province: Archean origins to modern lithospheric architecture
Authors: Chamberlain Kevin R , Frost Carol D , Frost B Ronald
Published: October 2003

Local preservation of 3.63.0 Ga gneisses and widespread isotopic evidence for crust of this age incorporated into younger plutons indicates that the Wyoming Province was a [Formula: see text] 100 000 km2middle Archean craton, which was modified by late Archean magmatism and tectonism and Proterozoic extension and rifting. On the basis of differences in late Archean histories, the Wyoming Province is subdivided into five subprovinces: three in the Archean core, (1) the Montana metasedimentary province, (2) the Bighorn subprovince, and (3) the Sweetwater subprovince, and two Archean terrains that may be allochthonous to the 3.0 Ga craton, (4) the Sierra Madre  Medicine Bow block, and (5) the Black Hills  Hartville block. A thick, fast lower crustal layer, imaged by Deep Probe, corresponds geographically with the Bighorn subprovince and may be an underplate associated with ca. 2.70 Ga mafic magmatism. The Sweetwater subprovince is characterized by an eastwest tectonic grain that was established by three or more temporally related, late Archean, pulses of basin development, shortening, and arc magmatism. This tectonic grain, including the 2.62 Ga Oregon Trail structure, controlled the locations and orientations of Proterozoic rifting and Laramide uplifts. The present-day lithospheric architecture of the Wyoming Province is the result of cumulative processes of crustal growth and tectonic modification; lithospheric contrasts have apparently persisted for billions of years. If there has been any net crustal growth of the Wyoming Province since 3.0 Ga, it has involved a combination of mafic underplating and arc magmatism.
Tectonic implications of magnetic fabrics and remanence in the Cooper Mountain pluton, North Cascade Mountains, Washington
Authors: Fawcett Tammy C , Burmester Russell F , Housen Bernard A , Iriondo Alexander
Published: October 2003

Documenting the timing and kinematics of deformation in orogens is critical to unraveling their history. Anisotropy of magnetic susceptibility defines the orientation of magnetic fabrics in the Eocene Cooper Mountain pluton in the North Cascade Mountains of Washington. The magnetic foliation typically has a steep dip and a northwest strike; the magnetic lineation plunges moderately to shallowly northwest or southeast. The remanent magnetization was measured to determine if the Cooper Mountain pluton has been tilted following emplacement. The remanence has two components. The characteristic remanence typically unblocks at 370 °C in most specimens, but at 580 °C in others. The two components are carried by pyrrhotite and magnetite. Mean directions of these components are indistinguishable from each other and from the North American expected Eocene direction. The paleomagnetic results and ~ 47 Ma 40Ar39Ar total fusion ages from biotite suggest that there has been no remagnetization or significant reorientation of the pluton since emplacement. Therefore, the in situ magnetic fabrics from the pluton can be used to understand the kinematics. Discordance of the fabrics with the pluton margin and near concordance with regional structures suggests that they have a tectonic origin. Thus the Cooper Mountain pluton is syntectonic rather than posttectonic. The magmatic fabric is slightly oblique to the length of the Cascade orogen, which can be explained if it formed as a consequence of regional dextral shear during transpression.
The impact of climate change on an emerging coastline affected by discontinuous permafrost: Manitounuk Strait, northern Quebec
Authors: Beaulieu Nancy , Allard Michel
Published: October 2003

A comparative analysis of air photos and a field survey show that permafrost-affected sectors of the coastline along Manitounuk Strait receded at an increasing rate between 1950 and 1995. These sectors are in bays where post-glacial Tyrrell Sea clays outcrop. During the same period, sand beaches at the mouths of streams and rock and till shorelines on headlands prograded at the pace of isostatic uplift. Permafrost that had aggraded and formed lithalsas and plateaus during the 19th century (i.e., during the Little Ice Age) had expanded over the tidal marsh and had locally provoked accelerated coastal emergence as frost heaving added to post-glacial isostatic uplift. Climate warming during the 20th century, particularly during the summer months, generated a chain of impacts involving forest growth, snow cover, ground warming, and permafrost degradation. Waves and tidal currents are mainly responsible for the evacuation and transport of thermokarst-produced silts and clays from the shore into the marine basin.
Spray freezing treatment of water from oil sands tailing ponds
Authors: Gao W , Smith Daniel W , Sego D C
Published: October 2003

Tailings pond water produced from the extraction of bitumen from the oil sands in Northern Alberta, Canada, was treated using the spray freezing process. The wastewater was frozen by spraying at 10°C and 24°C ambient temperatures. The effect of the degree of freezing (i.e., freezing with and without runoff generation) of the sprayed water on the treatment efficiency, the concentration, and distribution of the impurities within the ice columns was examined. When the sprayed water only partially froze (i.e., freezing with runoff formation), the treatment efficiency (measured by reduction in COD, TOC, conductivity, Cl, SO42 concentrations) was higher and larger volumes of high quality meltwater was obtained. Reduction of toxicity (Microtox) in meltwater, and the relationship between the overall impurity removal and toxicity reduction was also examined in this study. The decay coefficients were determined for prediction of meltwater impurity concentrations using mathematical models.Key words: spray freezing, wastewater treatment, oil sands tailings pond, toxicity reduction.
Aboveground dry matter partitioning responses of black spruce to directional-specific indices of local competition
Authors: Newton P F , Jolliffe P A
Published: October 2003

This study assessed the effects of directional-specific indices of local competition on the partitioning of aboveground dry matter of individual black spruce (Picea mariana (Mill.) BSP) trees. Historical tree reconstruction sampling techniques were used to estimate stem, branch, and foliage ovendry masses by year of formation (cohort age-class) of 125 subject trees situated within 15 density-stressed stands. Component-specific modular mass proportion calculated on an individual and cumulative cohort age-class basis was employed as an index of dry matter partitioning. Analytically, local competitors were stratified into one of four competition classes based on their relative size differential with respect to the subject tree. Sequential competition analysis was used to assess directional-specific partitioning responses to competition accumulating upwards from below and downwards from above. Furthermore, within the sequential competition analysis framework, the effects of the individual competition strata on partitioning were assessed employing stepwise multivariate analysis of variance. The results supported the presence of an asymmetric relationship dominated by competition from above in which branch partitioning was the most affected. Specifically, competition from larger-sized competitors resulted in decreased branch mass proportions whereas competition from smaller-sized competitors had no appreciable effect. These results are in accord with the hypothesis that black spruce responds to competition via an adaptive phenotypic plastic response in which branch growth declines and (or) branch abscission rates increase with increasing competition from above.
Interpretation of landscape pattern and habitat change for local indicator species using satellite imagery and geographic information system data in New Brunswick, Canada
Authors: Betts Matthew G , Franklin Steven E , Taylor Ron G
Published: October 2003

We measured the extent and rate of habitat change and interpreted landscape metrics for fragmentation in the Fundy Model Forest, New Brunswick, from 1993 to 1999 using geographical information system baseline data updated with landscape changes detected on Landsat satellite imagery. We report on three categories of landscape metrics (habitat cover, patch size, and nearest neighbour), which we interpret as applicable to potentially fragmentation-sensitive local indicator species in specific habitat types. Between 1993 and 1999, 5.6% of forest land in the Fundy Model Forest was estimated by satellite image analysis as having >30% of canopy cover removed, primarily as a result of forest harvesting treatments. In four of five habitat types, the rate of habitat loss from harvesting outpaced habitat replacement due to forest growth. Changes in landscape pattern metrics indicate that fragmentation has occurred in each of the five indicator species habitat types over the available time period; furthermore, the rate of fragmentation exceeded the rate of habitat loss. Declines in the number and area of mixedwood patches dominated the fragmentation of the landscape in this region. More attention to the spatial distribution of harvesting activities may be necessary to change this trend in landscape pattern in the future.
Nitrogen availability and forest productivity along a climosequence on Whiteface Mountain, New York
Authors: Joshi Amishi B , Vann David R , Johnson Arthur H , Miller Eric K
Published: October 2003

We studied broadleaf and needle-leaf forests along an elevation gradient (6001200 m) at Whiteface Mountain, New York, to determine relationships among temperature, mineral N availability, and aboveground net primary productivity (ANPP) and controls on the latter two variables. We measured net N mineralization during the growing season, annual litterfall quantity and quality, aboveground woody biomass accumulation, and soil organic matter quality. Inorganic N deposition from cloudwater markedly increases mineral N availability above 1000 m in this region. Consequently, mineral N availability across the climosequence remains relatively constant because N mineralization decreases with increasing elevation. Across this climosequence, air temperature (as growing season degree-days) exerted the most control on ANPP. Nitrogen mineralization was most strongly related to soil growing season degree-days and less so to lignin to N ratios in litter. ANPP was correlated with N mineralization but not with mineral N availability. Combining our data with those from similar studies in other boreal and cool temperate forests shows that N mineralization and ANPP are correlated at local, regional, and interbiome scales. Regarding the persistent question concerning cause and effect in the N mineralization  forest productivity relationship, our data provide evidence that at least in this case, forest productivity is a control on N mineralization.
Genetics of physical wood properties and early growth in a tropical pine hybrid
Authors: Shepherd Mervyn , Cross Michael , Dieters Mark J , Harding Kevin , Kain Dominic , Henry Robert
Published: October 2003

Quantitative trait locus (QTL) detection was carried out for physical wood properties and early growth traits in an interspecific hybrid between Pinus elliottii var. elliottii Engelm. and Pinus caribaea var. hondurensis (Sénécl) Barr. et Golf. A pseudo-testcross QTL detection strategy was used to identify genome regions that influenced wood density, secondary growth, and dry wood mass index on each genetic map for the parents of a single F1family (n = 133). Traits were measured for annual ring and earlywood and latewood components and were based on both individual and average ring values from 1996 to 1999. A total of 12 significant putative QTLs were identified that clustered into four genomic regions in the P. elliottii var. elliottii parent and a single region in the P. caribaea var. hondurensis parent. The P. elliottii var. elliottii parent largely contributed putative QTLs for diameter growth and wood density, whereas the P. caribaea var. hondurensis parent contributed a putative QTL for earlywood formed in 1997. Putative QTLs that influenced density and ring width did not colocate, suggesting independent inheritance of these characters. This was consistent with the lack of genetic correlation between wood density and diameter growth observed in quantitative studies in hybrid pines.
Périodicité et synchronisme des épidémies de la tordeuse des bourgeons de l'épinette au Québec
Authors: Jardon Yves , Morin Hubert , Dutilleul Pierre
Published: October 2003

A time series analysis was performed on 32 dendrochronological chronologies using Dutilleul's multi frequential periodo gram. Our aim was to estimate the periodicities of spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks in the province of Quebec. Our analysis estimated a signal of 25-38 years corresponding to spruce budworm outbreaks. Analyses conducted in the 20th century indicated the existence of true periodicities in half of the series suggesting local population dynamics. These periodicities were estimated to be 29-34 years. For the other series, outbreaks were explained by the addition of a second periodic component to the fundamental periodicity. These combined periodicities (pseudoperiodicities or complex periodicities) described most of the 130-year series analysed. The lack of several outbreaks explained part of the combined periodicity. The results suggest a migration effect and complex local population dynamics. A third periodic component explains the double epidemic waves. These estimated periodicities are often similar and in phase. We believe that a common regional effect (the Moran effect) acts on the minor fluctuations of the insect populations and helps synchronize the outbreaks. This research shows that different types of outbreak dynamics can be found within a same insect species.
The soil acidbase status of boreal black spruce stands after whole-tree and stem-only harvesting
Authors: Bélanger Nicolas , Paré David , Yamasaki Stephen H
Published: October 2003

The effect of different harvesting practices on soil acidbase status was evaluated in black spruce (Picea mariana (Mill.) BSP) forests of Quebec by comparing soil from five pairs of whole-tree and stem-only harvested plots 3 years after harvest. Stem-only harvesting contributed to the enrichment of the exchangeable base cation pool, particularly in the forest floors of the pairs where whole-tree harvested plots showed the highest exchangeable Al3+. In the mineral soil, divergence between treatments was low, perhaps because these acidic soils were strongly saturated with Al3+(about 90%), which did not favour cationic exchange reactions. Although the effects of treatment may not persist over time, improved base cation nutrition may benefit stands during the early stages of development. Over a forest rotation of about 85 years, the estimated loss of alkalinity due to whole-tree harvesting was estimated to be low (less than 20%) when compared with the effect of acidic deposition.
Multifactor classification of forest landscape ecosystems of Jocassee Gorges, southern Appalachian Mountains, South Carolina
Authors: Abella Scott R , Shelburne Victor B , MacDonald Neil W
Published: October 2003

Ecosystem classification identifies interrelationships within and among the geomorphology, soils, and vegetation that converge to form ecosystems across forest landscapes. We developed a multifactor ecosystem classification system for a 13 000 ha southern Appalachian landscape acquired in 1998 by the South Carolina Department of Natural Resources. Using a combination of multivariate analyses, we distinguished five ecosystem types ranging from xeric oak (Quercus spp.) to mesic eastern hemlock (Tsuga canadensis (L.) Carrière) ecosystems. Ecosystems segregated along geomorphic gradients influencing potential moisture availability, with soil properties such as solum thickness distinguishing among ecosystems occupying similar topographic positions. Our results suggest that different combinations of geomorphic and soil factors interact to form similar ecosystems across the landscape, and a given environmental factor can impact ecosystem development at some constituent sites of an ecosystem type but not at other sites. A regional comparison of ecosystem classifications indicates that environmental variables important for distinguishing ecosystems in the southern Appalachians vary, with Jocassee Gorges characterized by unique suites of environmental complexes. Our study supports the contention that the strengths of ecosystem classification are providing (i) comprehensive information on the interrelationships among ecosystem components, (ii) a foundation from which to develop ecologically based forest management plans, and (iii) an ecological framework in which to conduct future research on specific ecosystem components or processes.
Influences of paper birch competition on growth of understory white spruce and subalpine fir following spacing
Authors: Comeau Philip G , Wang Jian R , Letchford Tony
Published: October 2003

Five years after spacing a young, 11 m tall paper birch (Betula papyrifera Marsh.) stand, we examine relationships between growth of understory white spruce (Picea glauca (Moench) Voss), subalpine fir (Abies lasiocarpa (Hook.) Nutt.), and level of birch retention. Our objectives were to evaluate the effectiveness of selected measures of competition for estimating the effects of the residual birch and to evaluate the influence of residual birch densities on growth responses of naturally regenerated subalpine fir and white spruce. Basal area of Scouler willow (Salix scouler iana Barratt) and birch were found to effectively predict light transmittance (diffuse noninterceptance). The best models for predicting 4-year volume growth of subalpine fir and white spruce incorporate initial crown volume of the subject trees and transmittance as independent variables. Lorimer's index and Hegyi's index gave similar results to those obtained using basal area and transmittance, suggesting that there is little benefit in including measurements of proximity in a competition index. For both species, the correlation between basal area increment and light was substantially stronger than observed for volume increment. However, height increment of both subalpine fir and spruce was only weakly correlated with measured light levels. The ratio of height increment to volume increment decreased with both increasing initial height and transmittance for subalpine fir and white spruce.
Influence of fertilization, weed control, and pine litter on loblolly pine growth and productivity and understory plant development through 12 growing seasons
Authors: Haywood James D , Goelz Jeffery C , Sayer Mary A. Sword , Tiarks Allan E
Published: October 2003

On a silt loam soil in central Louisiana, three cultural treatments were applied to a seedling loblolly pine (Pinus taeda L.) plantation. The treatments were in a 2 × 2 × 2 factorial design: (1) no fertilization or a broadcast application of 177 kg N/ha and 151 kg P/ha; (2) no herbicides applied or broadcast or spot applications of hexazinone, sulfometuron methyl, or glyphosate herbicides and felling as required to control competing vegetation during the first three growing seasons; and (3) no litter applied or broadcast application of pine litter to form a 10 to 15 cm layer in the first growing season. Through 12 growing seasons, the fertilization or herbicide treatment significantly increased stand growth (α = 0.05), and these two treatments had an additive effect (no treatments, 209 m3/ha; fertilization, 328 m3/ha; herbicide, 280 m3/ha; fertilization and herbicide, 362 m3/ha). However, because litter application probably had a minor fertilization effect, the fertilizer and litter combination produced the greatest yield (370 m3/ha). The herbicide and litter combination adversely affected pine survival, and so applying all three treatments was no more effective than fertilization alone. The loblolly pine overstory was the dominant factor influencing the long-term development of the understory.
Responses of herbs and shrubs to reduced root competition under canopies and in gaps: a trenching experiment in old-growth Douglas-fir forests
Authors: Lindh Briana C , Gray Andrew N , Spies Thomas A
Published: October 2003

We tested the effect of root trenching on vegetation in closed-canopy and gap locations in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests. Based on theory, we expected belowground competition to be intense in a region with low summer rainfall, and trench responses were expected to be greater in the high light environment of the gaps. We installed 1 m deep trenches around study plots and lined the trenches to prevent reinvasion by tree roots. Soil moisture was measured monthly during the growing season for the first 3 years after trench installation. Vegetation in these trenched plots was compared with control plots 10 years after installation of the plots. Trenched plots with no vegetation manipulation averaged 92% total understory cover, while untrenched plots averaged 47% cover. Contrary to our expectation, both vegetation and soil moisture responses to trenching were greater in areas of high tree canopy cover than in gaps. Trenched plots under closed canopies were moister than control plots throughout the growing season, while the trenching effect became apparent in the overall wetter gaps only at the end of the growing season. We conclude that understory plants at these sites were limited at least as much by belowground competition as by aboveground competition.