bluuebunny/crossref_metadata_2025 huggingface dataset:
Low organisational justice and heavy drinking: a prospective cohort study
Authors: Kouvonen Anne , Kivimäki Mika , Elovainio Marko , Väänänen Ari , De Vogli Roberto , Heponiemi Tarja , Linna Anne , Pentti Jaana , Vahtera Jussi
Published: July 2007

Objectives:

To investigate whether low perceived organisational injustice predicts heavy drinking among employees.

Methods:

Data from a prospective occupational cohort study, the 10-Town Study, on 15 290 Finnish public sector local government employees nested in 2432 work units, were used. Non-drinkers were excluded. Procedural, interactional and total organisational justice, heavy drinking (⩾210 g of absolute alcohol per week) and other psychosocial factors were determined by means of questionnaire in 2000–2001 (phase 1) and 2004 (phase 2). Multilevel logistic regression analyses taking into account the hierarchical structure of the data were conducted and adjustments were made for sex, age, socio-economic status, marital status, baseline heavy drinking, psychological distress and other psychosocial risk factors such as job strain and effort/reward imbalance.

Results:

After adjustments, participants who reported low procedural justice at phase 1 were approximately 1.2 times more likely to be heavy drinkers at phase 2 compared with their counterparts reporting high justice. Low perceived justice in interpersonal treatment and low perceived total organisational justice were associated with increased prevalence of heavy drinking only in the model adjusted for sociodemographics.

Conclusions:

This is the first longitudinal study to show that low procedural justice is weakly associated with an increased likelihood of heavy drinking.
Swell–compression behaviour of compacted clays under chemical gradients
Authors: Rao Sudhakar M , Thyagaraj T
Published: July 2007

The present study examines the effect of inflow of sodium chloride solutions on the swell–compression behaviour of compacted expansive clays under a range of external loads. Inflow of sodium chloride solutions reduced the swell magnitudes and pressures and even caused the compacted clay specimens to experience compressive strains in oedometer tests. The axial strain difference of specimens inundated with sodium chloride solutions and distilled water at a constant effective stress predicted the osmotic consolidation strains of a saturated clay specimen from an increase in osmotic suction in the pore fluid. Specimens exposed to larger osmotic suction gradients (Δπ) are predicted to experience larger osmotic consolidation strains. The predicted osmotic consolidation strains exceeded the experimental osmotic consolidation strains. The free-swell and load method and the swell under load procedure predicted different swell pressures owing to differences in strain contributions at the microstructure and macrostructure levels. The increase in osmotic suction in pore water apparently acts as an equivalent net stress (ρπ) that favours a reduction in swell potential of the compacted clay specimens due to a reduction in reversible swelling strains from an increase in net stress and irreversible macrostructural component that decreases because the distance of the stress point to the load–collapse (LC) curve decreases.Key words: compacted clays, chemical gradients, osmotic consolidation, suction, swell.
Sulfur concrete for haul road construction at Suncor oil sands mines
Authors: Abraha Dawit G , Sego David C , Biggar Kevin W , Donahue Robert
Published: July 2007

The feasibility of constructing mine roads at oil sands mines (Fort McMurray, Alberta) using concrete prepared from bitumen extraction and upgrading by-products and mine wastes (sulfur, fly ash, coke, and tailing sand) is evaluated. An extensive laboratory test program, including unconfined compression testing, sonic velocity measurement, and split tensile and freeze–thaw durability tests, was carried out to characterize the physical and mechanical properties of different mix designs of sulfur concrete. A study of the geochemical interaction of sulfur concrete with the near-surface environment included short-term interaction of surface-exposed sulfur concrete during the construction and operational life of the haul road and long-term interaction of sulfur concrete with groundwater following its eventual burial with mine wastes in the mined-out pits. Haul road test sections were designed based on the critical strain and resilient modulus design method. Stress and strain distributions in the selected haul road cross section induced by the truck tires were calculated using finite element analysis. Required pavement layer thicknesses were then determined on the basis of the truck loads, and resilient modulus and strength of the sulfur concrete and subgrade material using the critical strain and resilient modulus design method.Key words: sulfur concrete, mine haul road design, concrete pavement.
Embankment on sludge: predicted and observed performances
Authors: Wu Tien H , Zhou Steven Z , Gale Stephan M
Published: July 2007

The case history of an embankment built over soft water-treatment sludge is presented. To assure that the sludge would consolidate and gain strength as predicted, a test embankment was built. The observed performance of the test embankment was compared with the predicted performance to verify and modify design assumptions. The results were used to design and construct the full-scale embankment. The finite element method and the critical state model were used to predict the performances of the test embankment and the full-scale embankment. Bayesian updating and system identification were used to update the material properties used in the prediction for the test embankment. The updated properties were then used to update the prediction for the test embankment and to predict the performance of the full-scale embankment. These predictions were compared with the observed performances to evaluate the accuracies of the predictions with different input data. Efforts were made to identify factors that cause differences between predicted and measured performances.Key words: Bayesian updating, consolidation, finite-element prediction, shear strength, stability, water-treatment sludge.
Shear strength, interparticle locking, and dilatancy of granular materials
Authors: Guo Peijun , Su Xubin
Published: July 2007

The effect of particle angularity on the strength and dilation of granular materials is investigated through a series of laboratory tests on two materials, Ottawa standard sand (Sand O) and crushed limestone (Sand L), that are made up of rounded and angular particles, respectively. Triaxial tests on both materials at different confining pressures and initial void ratios show that particle angularity has a substantial effect on both the peak friction angle ϕpand the mobilized friction angle at the onset of dilation, ϕf. It is found that ϕfis smaller than the critical friction angle ϕcvfor Ottawa sand; nevertheless ϕfis larger than ϕcvfor Sand L owing to interparticle locking induced by particle angularity. The experimental results clearly show the contributions to shear resistance from both dilation and interlocking, with interlocking still largely existing at the peak stress ratio but not at the critical state. Suggestions are made to modify the stress–dilatancy formulations for sand to take into account the effect of interparticle locking associated with particle angularity.Key words: granular material, dilatancy, interlocking, and particle shape.
Plant nitrate reductase activity as an indicator of availability of nitrate in forest soils
Authors: Högberg P. , Granström A. , Johansson T. , Lundmark-Thelin A. , Näsholm T.
Published: July 2007

The nitrate reductase activity of Deschampsiaflexuosa (L.) Trin., an evergreen grass species common in northern coniferous forests, was tested as an indicator of nitrate availability in forest soils. A positive linear correlation (correlation coefficient significantly different from zero, p < 0.01) was found between nitrate supply and nitrate reductase activity in shoots of seedlings in sand cultures. Throughout a vegetation period the nitrate reductase activity of D. flexuosa was constantly 2–16 times higher in a clear-cut area as compared with an adjacent forest. High enzyme activity, however, indicated significant amounts of nitrate also in the forest during spring and autumn. On plots heavily fertilized with urea the nitrate reductase activity was up to three times higher than on control plots, which suggests considerable nitrate formation on the former. The plant nitrate reductase activity method seemed to be an inexpensive, rapid, nondisturbing, semiquantitative indicator of nitrate availability in soils, particularly for time-course studies and in comparisons between experimental plots. Tests of maximal induction of nitrate reductase activity can reveal to what extent factors other than the supply of nitrate are limiting the activity.
On the presentation of statistical analysis: reason or ritual
Authors: Warren William G.
Published: July 2007

This paper addresses the shortcomings in the presentation of statistical analyses appearing in this and similar journals. The role of statistical analysis is, in general terms, to provide criteria to assist in decision making under conditions of uncertainty. Commonly, this means deciding whether two treatments yield different results based on an experiment. The actual decision or interpretation must remain the responsibility of the researcher and, thus, can and should contain elements of subjectivity. There is, therefore, a need to separate the objective (statistical) analysis of data from its interpretation as well as to present all of the relevant information concerning the objective analysis. Current deficiencies in presentation include (i) failure to specify the assumptions on which an analysis is based, (ii) failure to provide sufficient quantitative information, (iii) failure to match the statistical analysis to the experimental situation, and (iv) failure to consider whether the assumptions on which an analysis has been based have been violated to an extent that would invalidate the results. Examples of these deficiencies from recent issues of this journal are cited with, where possible, suggestions on how the presentation could be improved. The present unfortunate situation is due to misinformation or lack of information, which stems in part, if not completely, from the ritualistic use of a few statistical methods and, in particular, statistical packages for computers that simply present the results of applying these methods, properly or otherwise.
Leaf morphology plasticity in response to light environment in deciduous tree species and its implication on forest succession
Authors: Goulet France , Bellefleur Pierre
Published: July 2007

Sun leaves of five deciduous tree species were shaded, while shade leaves of the same species were exposed to direct rays of the sun prior to budbreak and during leaf expansion. Thickness, area, and density thickness (fresh weight per unit area) were measured and compared with sun and shade leaves that were used as a control. These parameters showed a considerable differentiation in leaf structure both for the control and treated leaves, particularly with very tolerant (American beech and sugar maple) and intermediate (yellow birch) species; this was apparently associated with the prevailing light conditions around a particular leaf from budbreak and during its development. Intermediate (red maple) and very intolerant (trembling aspen) species did not show true sun and shade leaves. The impact of these leaf adaptations on forest succession is also discussed.
Variance propagation in growth and yield projections
Authors: Mowrer H. T. , Frayer W. E.
Published: July 2007

This paper reports the results of a study on the propagated variance associated with stand estimates in a forest growth and yield model. A cumulative variance as a result of input measurement and regression estimation errors is propagated in a growth and yield model using the method of statistical differentials. To provide an assessment of relative performance, these variance estimates are compared with a Monte Carlo simulation estimate of propagated error for increasing levels of sampling intensity. The method of statistical differentials is used to estimate the propagated variance through five 10-year growth projections. The results indicate growth projection estimates may have substantial error components that are not readily apparent from model calibration statistics or bias assessment procedures.
Relationships among forest strata and environment in southern coastal British Columbia
Authors: Gagnon Daniel , Bradfield Gary E.
Published: July 2007

Data from coastal forests on west-central Vancouver Island were used to examine correlations between compositional variation in six forest strata among themselves (trees, saplings, tree seedlings, shrubs, herbs, and bryophytes) and with site environmental variables. These relationships were examined with data from three geographical areas: (i) a dry inland area dominated by Pseudotsugamenziesii, (ii) a wet coastal area dominated by Thujaplicata, and (iii) the entire study area including a few sites dominated by Abiesamabilis. Principal component analysis was used to summarize the main compositional variation within the strata of each of the three areas. Canonical correlation analysis was then used to assess the degree of correlation among strata, as well as between strata and several environmental variables. Patterns of correlation among strata differed in the three geographical areas analysed. The most strongly correlated strata were commonly associated with similar environmental factors, although the total variance in the data explained by the correlations was low (< 18%). Strata growing on rotting logs, in many parts of the study area (saplings, tree seedlings, shrubs, and bryophytes), tend to be highly intercorrelated. These same strata are weakly correlated with the herb stratum, which does not occur on rotting logs.
Visible injury and growth responses of young cuttings of Populuscanadensis and P. nigra to nitrogen dioxide and sulphur dioxide
Authors: Eastham Andrea M. , Ormrod Douglas P.
Published: July 2007

Carolina poplar (Populuscanadensis Moensch 'Eugenei') and Lombardy poplar (Populusnigra L. 'Italica') were exposed to NO2 and SO2, separately or in combination, for 1 h using concentrations of 0.50 and 1.0 μL•L−1 in separate experiments to determine if foliar injury symptoms can be used as a surrogate for growth effects and if single pollutants have noninteractive effects when mixed. Lombardy poplar was more sensitive than Carolina poplar to exposures to combined SO2 and NO2 at 1.0 μL•L−1 based on visible foliar injury symptoms. In contrast, leaf growth in both species was significantly stimulated by NO2 at 0.50 μL•L−1 and stem growth significantly decreased by NO2 at 1.0 μL•L−1. There was little effect of SO2; there were significant interactions of NO2 and SO2 only in Lombardy poplar exposed to 0.50 μL•L−1. These results suggest that growth effects can not be predicted by foliar injury symptoms and that few significant growth effects are identifiable in short-term studies.
Megagametogenesis, fertilization, and embryo development in Larixdecidua
Authors: Kosiński Grzegorz
Published: July 2007

The phenology of sexual reproduction in Larixdecidua Mill, varies from year to year, and some intra- and inter-clonal differences were also found. Megaspore mother cell meiosis occurred at the time of pollination, during the second half of April, resulting in three or four megaspores. The free nuclear stage and cell wall and archegonia formation were completed in late May and the first half of June. An average of four archegonia was observed in each ovule, but the number ranged from two to six. Fertilization occurred during the first 20 days of June, about 7 weeks after pollination. A four-tiered, 16-celled proembryo formed. Meristematic regions formed in the embryo from the end of June to mid-July. Fully developed embryos were observed in mid-August. Simple polyembryony and delayed cleavage polyembryony were observed. Lack of pollination, disturbances during megasporogenesis and female gametophyte development, failure of fertilization, and embryo degeneration are the major factors resulting in empty seed.
Six-year field performance of container-grown and bare-root black oak seedlings inoculated with Pisolithustinctorius and outplanted on two Ozark clear-cuts
Authors: Parker William C. , Moorhead David J. , Pallardy Stephen G. , Garrett H. E. , Dixon Robert K. , Sander Ivan L.
Published: July 2007

The effects of container culture and infection with Pisolithustinctorius (Pers.) Coker and Couch on growth and survival of black oak (Quercusvelutina Lam.) seedlings outplanted on two Missouri Ozark clear-cuts were examined over 6 years. Container-grown 1-0 seedlings exhibited height and diameter growth superior to bare-root stock, and mycorrhizal plants were taller than nonmycorrhizal plants during the first two to three field seasons. Thereafter, container-grown and bare-root, and mycorrhizal and nonmycorrhizal seedlings grew at comparable rates such that treatment differences in height and diameter had been greatly reduced 6 years after outplanting. Seedling growth and survival differed between sites, a response resulting from differential soil moisture availability and the nature of competing vegetation of the two planting sites. Shading by more abundant herbaceous and low woody vegetation on a comparatively mesic site likely resulted in greater mortality and less stem growth than on a xeric site during years 1 to 3. However, seedlings that grew to heights sufficient to overtop neighboring vegetation on the mesic site exhibited comparatively greater growth rates in years 4 to 6. As a result, after 6 years, the xeric site was occupied by a relatively large number of small seedlings, while the mesic site was characterized by fewer but larger seedlings.
Fine root growth dynamics in teak (Tectonagrandis Linn. F.)
Authors: Srivastava S. K. , Singh K. P. , Upadhyay R. S.
Published: July 2007

Temporal variations in the spatial distribution of fine root mass were studied in a 19-year-old teak plantation in a dry tropical region. The soil block method was used to investigate fine root dynamics. Quantification of fine root mass was achieved in terms of live teak roots (separated by diameter), dead teak roots, teak root bark, herb roots, and fragmented soil organic matter. The annual mean fine root biomass was 5420 kg•ha−1 and the net production was 5460 kg•ha−1•year−1. The bulk of the root mass was distributed at a depth of 10–30 cm and roots ≤2 mm constituted one-half or more of the total root biomass. Maximum live root growth occurred during the rainy season. All root sizes showed similar bimodal seasonal patterns, but the maximum:minimum ratio generally declined with greater root size.
Respiration in lodgepole pine parasitized by American dwarf mistletoe
Authors: Wanner Jim , Tinnin Robert O.
Published: July 2007

Rates of dark respiration were determined for foliated twig tips of branches from Pinuscontorta and for aerial shoots of Arceuthobiumamericanum. Tree samples were obtained from twigs of branches on uninfected trees, twigs from uninfected branches on infected trees, and from uninfected twigs of branches having localized infections. Rates of dark respiration were significantly lower for twigs from infected trees as compared with twigs from uninfected trees. The rate of dark respiration for aerial shoots of A. americanum was significantly higher than the host samples. The biomass of plant parts from infected and uninfected P. contorta was measured. We found that the ratio of relative bole to branch mass changed from 3.8:1 for lightly infected trees to 1.6:1 for heavily infected trees. This apparent shift in mass allocation from stem to branch wood would account for a portion of the reduction in timber volume that is associated with infection by Arceuthobium.
Syllepsis in Larixlaricina: occurrence and distribution of sylleptic long shoots and their relationships with age and vigour in young plantation-grown trees
Authors: Powell G. R. , Vescio Shelley A.
Published: July 2007

not available
Root-rot diseases of the rubber tree in the Ivory Coast. 1. Severity, dynamics, and characterization of epidemics
Authors: Nandris Daniel , Nicole Michel , Geiger Jean Paul
Published: July 2007

An epidemiological survey was carried out in a rubber tree (Heveabrasiliensis Willd. ex A. Juss) plantation to study and describe the epidemics of the root-rotting fungi Rigidoporuslignosus (Klotzsch) Imazeki and Phellinusnoxius (Corner) G. Cunn. Infection and mortality of the trees were systematically recorded half-yearly for 6 years. During the first year, the outbreak resulted in a considerable enlargement of the initial disease centers and the appearance of new ones. Pathogen activity was found to decrease 6 years after planting. This was attributed to the increase in defense reactions with the age of the tree and to disruption of trophic connections between forest inocula and decaying taproots of rubber trees. The type of root disease is discussed, mainly in terms of the kinetics of the creation of disease centers.
Late Quaternary vegetation history of Kettlehole Pond, southwestern Yukon
Authors: Cwynar Les C.
Published: July 2007

A pollen diagram with a detailed chronology reveals Late-Pleistocene and Holocene vegetation changes which, in combination with previously published data, provide information on regional vegetation changes in the western boreal forest of the southwestern Yukon. A Populus woodland with an understory of Shepherdiacanadensis and extensive open areas dominated by Artemisia occurred from 11 030 to 9250 BP. Juniperus populations expanded at 9700 BP and then more-mesic forest communities developed when Piceaglauca populations increased at 9250 BP and Populus declined. At 6100 BP there is a remarkable shift from Piceaglauca woodland with Juniperus to a mixed spruce forest in which P. mariana was the dominant species. At 4100 BP conditions altered to favour P. glauca which expanded at the expense of P. mariana, and Juniperus again became important in the vegetation. By 1900 BP Pinuscontorta had become a dominant tree as P. mariana declined, the latter eventually disappearing from the local vegetation. There is no evidence that grasslands were more extensive in the early Holocene, as has been hypothesized for the southwestern Yukon. The vegetation sequence implies an initial period of aridity from 11 030 to 9250 BP, when summer warmth was probably greater than that of the modern climate, a period of increased effective moisture between 9250 and 6100 BP, when Piceaglauca was abundant, even greater effective moisture between 6100 and 4100 BP, when Piceamariana was the dominant forest tree, and then a prolonged period of increasing aridity beginning at 4100 BP and culminating in the development of the modern semi-arid climate.
Predicting postfire mortality of seven western conifers
Authors: Ryan Kevin C. , Reinhardt Elizabeth D.
Published: July 2007

We used data on 2356 trees from 43 prescribed fires in Idaho, Montana, Oregon, and Washington states to model postfire tree mortality. Data were combined for seven species of conifers to develop binary logistic regression models for predicting the probability of mortality. Probability of mortality increased with percentage of the crown killed, and decreased as bark thickness increased. Models are presented with and without species as a categorical variable. The models predicted well for trees burned in both slash fires and fires in natural fuels. The models are applicable for assessing fire-caused mortality both of individual trees and in mixed conifer stands of the Pacific Northwest.
Total wood, sapwood, and heartwood in branch bases of three conifers
Authors: Kyker-Snowman Thomas D. , Wilson Brayton F.
Published: July 2007

Branches were cut from forest-grown, 15- to 85-year-old Picearubens, Pinusstrobus, and Tsugacanadensis trees. For 1139 branches we measured (i) cross-sectional sapwood, colored heartwood, and total wood areas at the branch base, (ii) dry weight of the needles and wood, and (iii) age. Branch age was a poor predictor of wood areas at the branch base. Regression analysis showed that branch wood dry weight was the best predictor of total wood area. Sapwood area was predicted equally well by needle dry weight or as a percentage of total wood area. The prediction was improved by using needle dry weight plus total wood area as variables. The mean ratio of sapwood area to needle dry weight was 0.72 mm2/g for Picearubens, 1.19 mm2/g for Tsugacanadensis, and 1.62 mm2/g for Pinusstrobus. Colored heartwood formed in the center of all branches older than 8 years. Heartwood area was a greater proportion of total wood area in older branches than in younger branches of any given tree, although absolute heartwood area was as variable as total wood area. The best estimates of heartwood area were obtained by subtracting estimates of sapwood area from total wood area. Heartwood area of the oldest branches (8–46 years) from each tree was 7–96% of total wood area at the branch base.
Growth trends in 10 species of trees in New England, 1950–1980
Authors: Hornbeck J. W. , Smith R. B. , Federer C. A.
Published: July 2007

Tree-ring measurements on increment cores collected from more than 5000 trees during a periodic survey of forest resources in New England indicate trends in regional basal-area increment by species for the period 1950–1980. Two species, red spruce and balsam fir, have had generally decreasing growth rates since the 1960s. Normal aging of the low-elevation, even-aged spruce–fir forest is a probable cause. Eight other species, including sugar maple, had constant or increasing growth throughout the period. White pine had considerably higher growth rates than the other species.
A two-stage method for horizontal point sampling in young forest stands
Authors: Brown Kenneth M. , Mugasha Ancelm G.
Published: July 2007

Horizontal point sampling is sometimes difficult to use in dense stands of small-diameter stems because of poor visibility. One solution to this problem is to use vertical point sampling in the field to obtain a larger than necessary preliminary sample. The diameter and distance of each tree in the vertical point sample is measured, and then a computational procedure identical with horizontal point sampling is used to subsample the vertical point sample tree list. For the method to work, it is necessary that the horizontal point sampling criterion be at least as limiting in a certain sense as the vertical point sampling criterion. Our principal result is to show how this necessary condition can be met.
An assessment of the structural method of deriving a black spruce site equation: Discussion
Authors: Payandeh Bijan
Published: July 2007

not available
Changes in osmotic potential of Douglas-fir (Pseudotsugamenziesii) seedlings in relation to temperature and photoperiod
Authors: Driessche R. van den
Published: July 2007

The influences of temperature and photoperiod on osmotic potential (ψπ) at full turgor (ψπSAT) of container-grown Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings, which had completed one growing season, were examined in four experiments. Osmotic potential was measured cryoscopically on expressed sap and also by the pressure volume curve method in experiment 4. In experiment 1, started in January when ψπSAT was low, seedlings exposed to 25 °C for 5 weeks showed an increase in ψπSAT of 0.48 MPa compared with seedlings held at 8 °C, which showed little increase. There were no differences in ψπSAT between 8- and 16-h photoperiods. In experiment 2, started in September when ψπSAT was relatively high, seedlings of interior origin showed decreases in ψπSAT at 8 °C under an 8-h photoperiod (0.55 MPa) and at 25 °C under a 16-h photoperiod (0.69 MPa). Relatively little decrease in ψπSAT occurred in interior seedlings at 8 °C under a 16-h photoperiod. Coastal seedlings showed no decrease in ψπSAT in this experiment. In experiment 3, seedlings were exposed to 1 and 8 °C under an 8-h photoperiod, but at lower irradiance levels (85 μE•m−2•s−1) than those used in the other experiments (340 μE•m−2•s−1). Starting at values of about −1.9 MPa in October, ψπSAT decreased, on average, for coastal and interior seedlings by 0.76 MPa at 1 °C and 0.42 MPa at 8 °C over 6 weeks. Values for coastal seedlings decreased less (0.36 MPa) than those for interior seedlings (0.83 MPa). In experiment 4, seedlings were maintained under ambient conditions outdoors (mean temperatures of 5 °C day and 3 °C night), or at 12 or 25 °C under a 10-h photoperiod, in January and February. After 5 weeks of treatment, ψπSAT at 25 °C was 0.50 MPa, measured cryoscopically, or 0.80 MPa, measured by the pressure-volume method, higher than for seedlings under ambient conditions. At the turgor loss point (ψπSAT), ψπ was 1.36 MPa higher at 25 °C than at ambient temperature. The increase in ψπSAT at the beginning of the season and the reduction of ψπSAT at the end of the season were therefore dependent on temperature, but an interaction of photoperiod with temperature was observed in September. Index of injury values, calculated from leakage of electrolytes from drought-stressed needles and stems, showed a linear relationship to moisture stress between − 10 and − 2 MPa xylem water potential. In experiment 4, needle and stem index of injury values increased with increase in temperature, as did ψπSAT and ψπTLP values, tending to confirm that information about drought tolerance can be obtained by either method.
Temporal changes in growth-layer patterns of plantation-grown red oak and red pine
Authors: Fayle D. C. F. , Bentley C. V.
Published: July 2007

The radial and longitudinal patterns of ring width were examined in the stems of dominant and intermediate red oak (Quercusrubra L.) and red pine (Pinusresinosa Ait.) in a 50-year-old plantation on a fine sandy soil. Patterns in red pine conform to those of plantation-grown conifers, which are characterized by a marked difference in width between the upper (maximum width) and lower (minimum width) parts of the growth layer. Except for the first decade from planting, overall patterns in the oak differed from those of the pine, and this is attributed primarily to differing branch development. Longitudinal changes in width were much less in the oak growth layers, so radial and ring-number sequences were relatively similar. Periods of reduced height increment in the oak, which were not as evident in the pine, tended to be associated with a reduction in ring width in the upper stem relative to the lower stem.
Above- and below-ground biomass and production of lodgepole pine on sites with differing soil moisture regimes
Authors: Comeau Philip G. , Kimmins James P.
Published: July 2007

The distribution of tree biomass and the allocation of production was measured in four stands of lodgepole pine (Pinuscontorta var. latifolia Engelm.), two growing on sites with xeric soil moisture regimes and two on sites with mesic soil moisture regimes. At the time of sampling the stands were 70–78 years old. Aboveground biomass ranged from 116.5 Mg•ha−1 on one xeric site to 313.1 Mg•ha−1 on one mesic site. Stem biomass represented 68 and 73% of total tree biomass on the xeric and mesic sites, respectively. Total root biomass represented between 20 and 28% of total lodgepole pine biomass. Fine and small roots (<5 mm diameter) represented 4 and 1.5% of total tree biomass on the xeric and mesic sites, respectively. Total net primary production ranged from 7.9 Mg•ha−1•year−1 on the xeric sites to 11.9 Mg•ha−1•year−1 on the mesic sites. Stemwood production represented 20 and 27% of total net primary production on the xeric sites and 35% on both mesic sites. Belowground production represented 38 and 46% of total net primary production on the two mesic sites (4.5 and 5.5 Mg•ha−1•year−1, respectively) and 55 and 66% on the two xeric sites (4.3 and 6.3 Mg•ha−1•year−1, respectively). Fine and small roots represented 82–94% of belowground production. Production allocation was in the following order: fine and small roots > stems > foliage > coarse roots > branches, for all but the wettest site, where stem production exceeded fine and small root production.
Assessing economic benefits of climate change on Canada's boreal forest
Authors: Kooten G. C. Van , Arthur Louise M.
Published: July 2007

Methods developed in applied welfare economics are used to determine the economic effects of climate change on Canada's boreal forest industry. Two climate scenarios are tested, both based on general circulation models for doubled concentrations of atmospheric CO2. Under both scenarios forest productivity increases; however, benefits accrue primarily to Canada's trading partners.
Input, accumulation, and residence times of carbon, nitrogen, and phosphorus in four Rocky Mountain coniferous forests
Authors: Prescott Cindy E. , Corbin John P. , Parkinson Dennis
Published: July 2007

Annual aboveground litterfall in forests of Pinuscontorta Loud., Piceaglauca (Moench) Voss, Piceaengelmannii Parry ex Engelm., and Abieslasiocarpa (Hook.) Nutt. in southwestern Alberta ranged from 286 to 321 g•m−2•year−1. The mass of litter accumulated on the forest floors ranged from 6.3 to 11.0 kg•m−2. Residence times of organic matter in the forest floor were 11 years in a 90-year-old P. contorta stand, 16 years in a 120-year-old P. glauca–P. contorta stand, and 23 years in a 350-year-old P. engelmannii–A. lasiocarpa stand. Residence times of litter in the L layer of the forest floor were longer in a recently clearcut area than in the older forests. Residence times of individual nutrients in the forest floors were in the order N > P > C. Litter in the pine forest had lower concentrations of both N and P than did litter in the spruce–pine forest; litter in the spruce–fir forest had relatively high N and low P concentrations. Differences in nutrient concentrations of litter among sites reflected differences in the nutrient-use efficiency of the vegetation, suggesting that the species composition of vegetation is important in determining availability of nutrients in the floor of these forests.
Allozyme variation in sugar maple at the northern limit of its range in Ontario, Canada
Authors: Perry D. J. , Knowles P.
Published: July 2007

Genetic variation in five populations of sugar maple (Acersaccharum Marsh.) from northern Ontario was analysed electrophoretically for seven enzymes encoded by 11 structural loci. On average, populations were polymorphic at 38.2% of the loci, with 1.95 alleles per locus. Although FST estimates indicated that only 3% of the genetic variability was among populations, there was significant allelic heterogeneity at all polymorphic loci. Canonical discriminant analysis also indicated substantial differentiation among populations. Genetic distances between populations ranged from 0.0009 to 0.0125, but no relationship with geographic distance was apparent. It is suggested that pockets of sugar maple found at the northern limit of its range in Ontario may be relics of a more continuous ancestral population which may have existed during the hypsithermal interval.
Aboveground organic matter and production of a montane forest on the eastern slopes of the Washington Cascade Range
Authors: Gower Stith T. , Grier Charles C.
Published: July 2007

Aboveground biomass and production were determined for a 70-year-old mixed conifer forest of western larch (Larixoccidentalis Nutt.), lodgepole pine (Pinuscontorta Dougl. var. latifolia Engelm.), and Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) on the eastern slopes of the Cascade Range in Washington state. Live aboveground biomass, projected leaf area, and aboveground net primary production for the mixed conifer forest were 194 Mg•ha−1, 4.2 m−2•m−2, and 6.1 Mg•ha−1•year−1, respectively. Based on the few studies of montane forests on the eastern slope of the Cascades, aboveground biomass, leaf area index, and aboveground net primary production of these forests are more similar to those of montane coniferous forests in the Rocky Mountains than to those of similar forests located on the western slopes of the Cascades.
Indirect selection and clonal propagation of loblolly pine seedlings enhance resistance to fusiform rust
Authors: Foster G. S. , Anderson R. L.
Published: July 2007

A population of loblolly pine (Pinustaeda L.) seedlings without fusiform rust (Cronartiumquercuum (Berk.) Miyabe ex Shirai f.sp. fusiforme) galls was developed by controlled-cross matings of parent trees with known rust resistance, and subsequent screening of the seedling offspring through artificial inoculation. The seedlings without rust galls then entered a vegetative propagation system using rooted cuttings. A second round of rust testing by artificial inoculation, using a random sample of 20 clones from the program, revealed a high degree of rust resistance (4% galled) compared with that of seedlings from either a resistant control seedlot (50% galled) or a susceptible control seedlot (81% galled). This apparently high degree of rust resistance may be due to genetic effects, rooted cutting morphology, or both.
ENTANGLEMENT SWAPPING AND CONCENTRATION IN THE TWO-PHOTON JAYNES-CUMMINGS MODEL
Authors: WANG YI-CAI , LIU JIN-MING
Published: July 2007

We propose a scheme for entanglement swapping and entanglement concentration without joint measurement by using the two-photon Jaynes-Cummings model. In the scheme, we can generate a maximally entangled pair between two initially uncorrelated atoms or cavities. Furthermore, the entangled state between two cavities is found to be a photon entanglement of two photons in one cavity and zero in another cavity.
THE BOLTZMANN–ENSKOG EQUATION NEAR MAXWELLIANS
Authors: DOGBÉ CHRISTIAN
Published: July 2007

Global-in-time classical solutions near Maxwellians are constructed for the Boltzmann–Enskog equation in a periodic box. This construction of the solutions is based on the energy method. Meanwhile, the exponential decay of such a solution is obtained.
Lacking cytokine production in ES cells and ES-cell-derived vascular cells stimulated by TNF-α is rescued by HDAC inhibitor trichostatin A
Authors: Zampetaki Anna , Zeng Lingfang , Xiao Qingzhong , Margariti Andriani , Hu Yanhua , Xu Qingbo
Published: July 2007

Inflammation and TNF-α signaling play a central role in most of the pathological conditions where cell transplantation could be applied. As shown by initial experiments, embryonic stem (ES) cells and ES-cell derived vascular cells express very low levels of TNF-α receptor I (TNFRp55) and thus do not induce cytokine expression in response to TNF-α stimulation. Transient transfection analysis of wild-type or deletion variants of the TNFRp55 gene promoter showed a strong activity for a 250-bp fragment in the upstream region of the gene. This activity was abolished by mutations targeting the Sp1/Sp3 or AP1 binding sites. Moreover, treatment with trichostatin A (TSA) led to a pronounced increase in TNFRp55 mRNA and promoter activity. Overexpression of Sp1 or c- fos further enhanced the TSA-induced luciferase activity, and this response was attenuated by Sp3 or c- jun coexpression. Additional experiments revealed that TSA did not affect the Sp1/Sp3 ratio but caused transcriptional activation of the c- fos gene. Thus, we provide the first evidence that ES and ES-cell-derived vascular cells lack cytokine expression in response to TNF-α stimulation due to low levels of c- fos and transcriptional activation of Sp1 that can be regulated by inhibition of histone deacetylase activity.
GATA-6 mediates human bladder smooth muscle differentiation: involvement of a novel enhancer element in regulating α-smooth muscle actin gene expression
Authors: Kanematsu Akihiro , Ramachandran Aruna , Adam Rosalyn M.
Published: July 2007

Hollow organs exposed to pathological stimuli undergo phenotypic modulation characterized by altered expression of smooth muscle contractile proteins and loss of normal function. The molecular mechanisms that regulate smooth muscle differentiation, especially in organs other than the vasculature, are poorly understood. In this study, we describe a role for the GATA-6 transcription factor in regulation of human bladder smooth muscle differentiation. Knockdown of endogenous GATA-6 in primary human bladder smooth muscle cells (pBSMC) led to decreased mRNA levels of the differentiation markers α-smooth muscle actin (α-SMA), calponin, and smooth muscle myosin heavy chain. Similar effects were obtained following downregulation of GATA-6 by forskolin-induced elevation of intracellular cAMP levels. Forskolin treatment of pBSMC abolished recruitment of GATA-6 to the α-SMA promoter in vivo and reduced activity of human α-SMA promoter-directed gene expression by >60%. This inhibitory effect was rescued by enforced expression of wild-type GATA-6 but not by a zinc-finger-deleted mutant, GATA-6-ΔZF, which lacks DNA-binding ability. In silico analysis of a region of the human α-SMA promoter, described previously as a transcriptional enhancer, identified a putative GATA-binding site at position −919/−913. Point mutation of this site in SMA-Luc abrogated GATA-6-induced activation of promoter activity. Together, these results provide the first evidence for a functional role for GATA-6 in regulation of bladder smooth muscle differentiation. In addition, these findings demonstrate that GATA-6 regulates human α-SMA expression via a novel regulatory cis element in the α-SMA promoter-enhancer.
Microtubules are needed for the perinuclear positioning of aquaporin-2 after its endocytic retrieval in renal principal cells
Authors: Vossenkämper Anna , Nedvetsky Pavel I. , Wiesner Burkhard , Furkert Jens , Rosenthal Walter , Klussmann Enno
Published: July 2007

Water reabsorption in the renal collecting duct is regulated by arginine vasopressin (AVP). AVP induces the insertion of the water channel aquaporin-2 (AQP2) into the plasma membrane of principal cells, thereby increasing the osmotic water permeability. The redistribution of AQP2 to the plasma membrane is a cAMP-dependent process and thus a paradigm for cAMP-controlled exocytic processes. Using primary cultured rat inner medullary collecting duct cells, we show that the redistribution of AQP2 to the plasma membrane is accompanied by the reorganization of microtubules and the redistribution of the small GTPase Rab11. In resting cells, AQP2 is colocalized with Rab11 perinuclearly. AVP induced the redistribution of AQP2 to the plasma membrane and of Rab11 to the cell periphery. The redistribution of both proteins was increased when microtubules were depolymerized by nocodazole. In addition, the depolymerization of microtubules prevented the perinuclear positioning of AQP2 and Rab11 in resting cells, which was restored if nocodazole was washed out and microtubules repolymerized. After internalization of AQP2, induced by removal of AVP, forskolin triggered the AQP2 redistribution to the plasma membrane even if microtubules were depolymerized and without the previous positioning of AQP2 in the perinuclear recycling compartment. Collectively, the data indicate that microtubule-dependent transport of AQP2 is predominantly responsible for trafficking and localization of AQP2 inside the cell after its internalization but not for the exocytic transport of the water channel. We also demonstrate that cAMP-signaling regulates the localization of Rab11-positive recycling endosomes in renal principal cells.
Advancing age produces sex differences in vasomotor kinetics during and after skeletal muscle contraction
Authors: Bearden Shawn E.
Published: July 2007

Little is known of the vasomotor responses of skeletal muscle arterioles during and following muscle contraction. We hypothesized that aging leads to impaired arteriolar responses to muscle contraction and recovery. Nitric oxide (NO) availability, which is age dependent, has been implicated in components of these kinetics. Therefore, we also hypothesized that changes in the kinetics of vascular responses are associated with the NO pathway. Groups were young (3 mo), old (24 mo), endothelial NO synthase knockout (eNOS−/−), and NG-nitro-l-arginine (l-NA)-treated male and female C57BL/6 mice. The kinetics of vasodilation during and following 1 min of contractions of the gluteus maximus muscle were recorded in second-order (regional distribution) and third-order (local control) arterioles. Baseline, peak (during contraction), and maximal diameters (pharmacological) were not affected by age or sex. The kinetics of dilation and recovery were not different between males and females at the young age. There was a significant slowing of vasodilation at the onset of contractions (∼2-fold; P < 0.05) and a significant speeding of recovery (∼5-fold; P < 0.05) in old males vs. old females and vs. young eNOS−/−, and l-NA did not affect the kinetics at the onset of muscle contraction. eNOS−/− mimicked the rapid recovery of old males in second-order arterioles; acute NO production (l-NA) explained ∼50% of this effect. These data demonstrate fundamental age-related differences between the sexes in the dynamic function of skeletal muscle arterioles. Understanding how youthful function persists in females but not males may provide therapeutic insight into clinical interventions to maintain dynamic microvascular control of nutrient supply with age.
Moderate hypothermia induces a preferential increase in pancreatic islet blood flow in anesthetized rats
Authors: Hultström Michael , Jansson Leif , Bodin Birgitta , Källskog Örjan
Published: July 2007

The aim of the study was to characterize the effects of induced moderate hypothermia on splanchnic blood flow, with particular reference to that of the pancreas and the islets of Langerhans. We also investigated how interference with the autonomic nervous system at different levels influenced the blood perfusion during hypothermia. For this purpose, hypothermia (body temperature of 28°C) was induced by external cooling, whereas normothermic (37.5°C) anesthetized Sprague-Dawley rats were used as controls. Some rats were pretreated with either propranolol, yohimbine, atropine, hexamethonium, or a bilateral abdominal vagotomy. Our findings suggest that moderate hypothermia elicits complex, organ-specific circulatory changes, with increased perfusion noted in the pylorus, as well as the whole pancreas and the pancreatic islets. The pancreatic islets maintain their high blood perfusion through mechanisms involving both sympathetic and parasympathetic mediators, whereas the increased pyloric blood flow is mediated through parasympathetic mechanisms. Renal blood flow was decreased, and this can be prevented by ganglionic blockade and is also influenced by β-adrenoceptors.