bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring Parent Participation in a Parent Training Program for Children's Aggression: Understanding and Illuminating Mechanisms of Change
Authors: Levac Anne Marie , McCay Elizabeth , Merka Patricia , Reddon‐D’Arcy Mary Lynn
Published: April 2008

PROBLEM:  Controlled trials have demonstrated that parents of children experiencing high levels of aggression benefit greatly from parent training programs. Several programs have shown a decrease in parental stress, an increase in parental confidence, and higher levels of prosocial behavior in children as shown by outcomes based on quantitative measures. However, less attention has been paid to the views and experiences of parents themselves about the impact of such programs on themselves, their children, and their parent–child relationships.

METHODS:  The purpose of this qualitative study was to elicit and explore parents’ perceptions of the effectiveness of the Incredible Years Parent Training Program. Following their participation in the Incredible Years Program, 37 parents completed a semistructured interview and completed demographic questionnaires. Data were analyzed employing a content analysis of the transcripts and descriptive statistics of the demographic data.

FINDINGS:  Parents strongly valued the support offered within the group therapy process, reporting a decrease in their stress levels, an increase in their confidence, as well as observing positive changes in their children and in the parent–child relationship.

CONCLUSIONS:  The findings of this research illuminate possible underlying mechanisms for these observed changes. Specifically, when parents feel accepted, supported, and not blamed by healthcare professionals, they seem to be able to engage in self‐reflection specifically related to their parenting styles. In turn, their ability to reflect in the group and make sense of their own thoughts, feelings, and behaviors seems to have a positive influence on the process of change in themselves, their children, and in their relationships with their children and other family members.
Iron Deficiency‐induced Increase of Root Branching Contributes to the Enhanced Root Ferric Chelate Reductase Activity
Authors: Jin Chong‐Wei , Chen Wei‐Wei , Meng Zhi‐Bin , Zheng Shao‐Jian
Published: April 2008

In various plant species, Fe deficiency increases lateral root branching. However, whether this morphological alteration contributes to the Fe deficiency‐induced physiological responses still remains to be demonstrated. In the present research, we demonstrated that the lateral root development of red clover (Trifolium pretense L.) was significantly enhanced by Fe deficient treatment, and the total lateral root number correlated well with the Fe deficiency‐induced ferric chelate reductase (FCR) activity. By analyzing the results from Dasgan et al. (2002), we also found that although the two tomato genotypes line227/1 (P1) and Roza (P2) and their reciprocal F1 hybrid lines (“P1 × P2” and “P2 × P1”) were cultured under two different lower Fe conditions (10−6 and 10−7 M FeEDDHA), their FCR activities are significantly correlated with the lateral root number. More interestingly, the ‐Fe chlorosis tolerant ability of these four tomato lines displays similar trends with the lateral root density. Taking these results together, it was proposed that the Fe deficiency‐induced increases of the lateral root should play an important role in resistance to Fe deficiency, which may act as harnesses of a useful trait for the selection and breeding of more Fe‐efficient crops among the genotypes that have evolved a Fe deficiency‐induced Fe uptake system.
A FUTURE POLICY IN THE GENERAL INTEREST
Authors: Tarditi Secondo
Published: April 2008

A future policy in the general interest

According to the Aristotelian Classification of policies, based on whether they promote the common good or that of particular interests, the present agricultural market policy is “degenerate”. Reform of the CAP in the general interest should strengthen structural and rural development policy while limiting market policy to price stabilisation. Existing commodity support (price + aids) should be “degressive and temporary” with a precise deadline. This would avoid abrupt shocks in farm incomes while favouring structural adjustment and reducing production costs. Problems related to price and investment distortions, production quotas, land set‐aside, modulation by farm size, extension of the CAP to new EU Members, would largely disappear.

A l'avenir, une politique de l'intérêt général

Dans la classification des politiques établie par Aristote, scion qu'elles recherchent le bien commun ou la satisfaction d'intérêts particuliers, la politique agricole actuelle figurerait dans la rubrique des politiques “dégénérées”. Si elle avait l'intérêt général en vue, la réforme de la PAC essaierait de renforcer les structures et le développement rural, tout en limitant ses interventions sur les marchés à la stabilisation des prix. Les soutiens existants aux produits (aides directes et soutiens aux prix) devraient être dégressifs et temporaires (avec des dates d'expiration bien déterminées). Cela éviterait des chocs brutaux sur les revenus agricoles, tout en favorisant les restructurations et en abaissant les coûts. Alors disparaîtraient la plus grande partie des problèmes de prix, d'investissement, de distorsions, de quotas de production, de gel des terres, de modulation par tailles, et d'extension de la PAC aux nouveaux membres de l'Union Européenne.

Eine zukünftige Politik im Sinne des Gemeinwohls

In Anlehnung an die aristotelische Einteilung von Ponukmaßnahmen, die nach der Orientierung am Gemeinwohl oder an Einzelinteressen erfolgt, handelt es sich bei der derzeitigen landwirtschaftlichen Marktpolitik um eine “entartete” Politik. Die Reform der GAP im Sinne des Gemeinwohls sollte die Strukturpolitik und die Politik zur Entwicklung des ländlichen Raums stärken und die Rolle der Marktpolitik auf die Preisstabilisierung beschränken. Die gegenwärtige Produktstützung (Preis und Beihilfen) sollte mit einer exakten Fristsetzung “degressiv und zeitlich begrenzt” sein. Dadurch würden starke Einkommenseinbußen bei den landwirtschaftlichen Betrieben vermieden und zusätzliche Anreize für strukturelle Anpassung und Senkung der Produktionskosten ausgeübt werden. Somit würden die Probleme größtenteils gelöst, die sich aufgrund von Verzerrungen der Preise und Investitionen, Produktionsquoten, Flächenstilllegung, Modulation nach Betriebsgröße und Erweiterung der GAP auf neue EU‐Mitgliedsstaaten ergeben.
Is agricultural policy aiming at the wrong target?
Authors: Boussard Jean‐Marc
Published: April 2008

Is agricultural policy aiming at the wrong target?

Modern political decision makers stress the benefits to be derived from a more market oriented agriculture. For this purpose, they are ready to grant guaranteed decoupled farmer income almost without precedent. They may have lost sight of the true historical reason for which the links between the market and agriculture had been severed during the 1930s, namely the market's inability, in the specific case of agriculture, to transmit relevant information between producer and consumer. In this context, ‘traditional’ agricultural policies may have provided more benefits for consumers than is usually acknowledged, and ‘new’ policies may result in more detrimental effects than expected.

La politique agricole se trompe‐t‐elle de cible?

A ľ heure actuelle, les décideurs politique mettent ľ accent sur les bénéfices à attendre de mesure visant a faire orienter ľ agriculture par le marché, et sont prêts, pour cela, à accorder aux agriculteurs une garantie de revenu presque sans contre‐partie. Ce faisant, ils semblent avoir perdu de vue la raison pour laquelle ľ agriculture avait été déconnectée du marché dans les années 30, à savoir ľ inaptitude du marché, dans le cas précis de ľ agriculture, à transmettre des informations pertinentes entre les producteurs et les consommateurs. Dans ce contexte, il se peut que les bénéfices des politiques ‘traditionnelles’ aient été beaucoup grands qu'on ne ľ admet généralement, tandis que les politiques ‘nouvelles’ seraient susceptibles engendrer plus ?‘effets négatifs qu’on ne s'y attend.

Verfolgt die Agrarpolitik ein falsches Ziel?

Die politischen Entscheidung sträger von heute heben die Vorteile hervor, die sich aus einer mehr marktorientierten Landwirtschaft ableiten lassen. Daher sind sie bereit, garantierte entkoppelte Einkommenszahlungen an Landwirte zu gewähren, obwohl es dafür noch nahezu keine Erfahrungen gibt. Möglicherweise haben sie den wahren historischen Grund übersehen, der zu einer Abkehr marktwirtschaftlicher Reglungen für die Landwirtschaft in den 1930ern geführt hat. Es war ein Marktversagen bei der Informationsweitergabe im landwirtschaftlichen Bereich zwischen Produzenten und Verbraucher festzustellen. Wird dieser Effekt berücksichtigt, so haben die ‘traditionellen’ landwirtschaftlichen Politikmaßnahmen möglicherweise mehr Vorteile für den Verbraucher gebracht als im allgemeinen angenommen, und ‘neue’ Politikmaßnahmen haben möglicherweise mehr Nachteile als angenommen.
Development of nine polymorphic microsatellite loci in the spined loach, Cobitis taenia, and cross‐species amplification in the related species C. elongatoides, C. taurica and C. tanaitica
Authors: DE GELAS K. , JANKO K. , VOLCKAERT F. A. M. , DE CHARLEROY D. , VAN HOUDT J. K. J.
Published: April 2008

Nine polymorphic microsatellite loci were developed for the spined loach, Cobitis taenia (Teleostei: Cobitidae). The loci were validated using 50 individuals from a population in Belgium. Moderate to high levels of polymorphism were detected (two to 11 alleles). In addition, most markers amplified successfully in three closely related taxa that are known to hybridize with C. taenia: C. elongatoides, C. taurica and C. tanaitica. Some of the loci are most likely diagnostic among species. These markers will be valuable for the study of the historical and contemporary interactions within C. taenia and the Cobitis species complex.
Comparison of oleoresin flow in relation to wound size, growth rates, and disease status of lodgepole pine
Authors: Nebeker T. E. , Tisdale R. A. , Schmitz R. F.
Published: April 2008

Total flow of lodgepole pine oleoresin was investigated in relation to size of wound, diameter class, disease status, and aspect (north and south). The two wound sizes were 2.54 and 5.08 cm in diameter. The diameter classes were 15.24, 20.32, and 25.40 cm. The disease classes were Armillaria root rot (Armillaria spp.), lodgepole pine dwarf mistletoe (Arceuthobium americanum Nutt. ex. Engelm.), and Comandra blister rust (Cronartium comandrae Pk.). It was found that the 5.08-cm wound resulted in almost twice as much resin flow as the 2.54-cm wound after 24 h. No differences in flow were found between size classes with the 5.08-cm wound. However, there was a general trend for flow to increase with an increase in diameter class. The 15.24-cm diameter class had significantly less flow than the other two diameter classes with the 2.54-cm wound. There was also a general trend for greater total flow on the north aspect. There was a general trend for greater resin flow in the diseased trees. It was also found that disease status had a significant effect on tree growth. The comandra blister rust trees put on significantly less growth than trees in the other two disease classes. Radial growth was also found to be greater on the north aspect of all trees. Interestingly, the mountain pine beetle (Dendroctonus ponderosae Hopkins) usually attacks the north aspect first then spreads or maintains a strip attack on that aspect. The role of the constitutive (primary) defensive system in conifers needs further study to understand the interactions taking place, especially from the host selection point of view during the endemic periods. During epizootic periods resources are utilized as a result of availability. But during endemic periods, to maintain the insect populations, host selection would seem critical for survival. Key words: resin flow, Pinus conforta, Armillaria, Cronartium, Arceuthobium, mountain pine beetle.
The role of environmental variables on interannual variation in species composition and biomass in a subtropical minerotrophic floating marsh
Authors: Sasser Charles E. , Visser Jenneke M. , Evers D. Elaine , Gosselink James G.
Published: April 2008

Floating marshes supporting emergent vascular vegetation occur in expansive areas in many parts of the world. We analyzed the long-term variability in species composition and related plant biomass to environmental variables in a subtropical minerotrophic floating marsh, Louisiana, U.S.A. Panicum hemitomon was the dominant plant species, representing 76% of the total mean end of season aboveground dry weight of 840 g∙m−2. Multivariate analyses showed that community structure in the Lake Boeuf floating marsh has changed little during the 11 years included in this study. Individual species occurring in varying frequency with the dominant, Panicum hemitomon, form two marginally distinct assemblages. Mean live end of season biomass varied from a low of 602 g dry wt∙m−2 to a high of 1173 g dry wt∙m−2 during the period of the study. Ninety-nine percent of the variation in total aboveground biomass can be predicted by environmental variables related to temperature, precipitation, evaporation, and water level. Mapping of the area for the years 1945, 1952, 1981, and 1992 show that a net loss of about 4% of marsh has occurred between 1945 and 1992. Key words: vegetation, stability, freshwater floating marsh, Panicum hemitomon, Louisiana, climate.
Conidial morphology, host colonization, and development of shot hole of almond caused by Wilsonomyces carpophilus
Authors: Adaskaveg J. E.
Published: April 2008

Morphology and ultrastructure of shot hole disease of almond infected by conidia of Wilsonomyces carpophilus were examined using light, scanning, and transmission electron microscopy. The multicelled conidia of the fungus were thick-walled and darkly pigmented. The conidial wall was multilayered and mainly consisted of an electron-dense, outer-wall layer and an electron-translucent, inner-wall layer. Septa of conidia were also multilayered. An electron-translucent zone separated the electron-dense, septa-wall layers of adjacent cells, and this zone extended to the inside of the outer-wall layer of a conidium. Conidia lacked true septa (distoseptate) and germinated by rupturing the outer-wall layers. Germination hyphae penetrated indirectly through stomata or directly through the cuticle into leaf tissue from appressoria that were produced terminally or on lateral branches of germ tubes. An extracellular mucilaginous matrix was commonly observed around hyphae and germ tubes in contact with leaf surfaces. Within leaf tissue, hyphae ramified throughout intercellular spaces and degraded cell walls of epidermal cells apparently without cuticle degradation. Diseased host tissue was tan brown and collapsed; ultrastracturally, diseased leaf cells were reduced in size, nonvacuolated, and had disrupted chloroplasts. A healthy host tissue response, adjacent to an infection site on leaves of potted plants, was the formation of a wound periderm. Within 10–14 days after an infection period (16 h of wetness), the periderm became a lignified–suberized barrier at 15 °C or a suberized abscission layer at 22 °C based on the histological stains Safranin O, Sudan III, and Sudan Black. At 15 °C, no abscission occurred and meristematic cells remained isodiametric but their walls became suberized and lignified, whereas cells adjacent to diseased tissue became lignified. At 22 °C, abscission occurred as cells adjacent to diseased tissue became vacuolated, enlarged, and suberized. Subsequently, the epidermis ruptured and the enlarged cells separated along the middle lamella to form an abscission layer. Hyphal growth was limited to the boundaries of the walled-off diseased tissue. Under favorable environmental conditions, hyphae replaced host epidermal cells and aggregated above the palisade layer to form pulvinate sporodochia. Sporodochia consisted of hyphae, numerous sympodially developing conidiogenous cells, and conidia that ruptured the host cuticle. Key words: fungal morphology, fungal foliar diseases, wound periderm, host–parasite interactions.
Incompatibility inCordia alliodora(Boraginaceae), a neotropical tree
Authors: Boshier D. H.
Published: April 2008

Incompatibility and variation in floral morphology in Cordia alliodora (R. & P.) Oken (Boraginaceae) were investigated using a combination of fieldwork and light and ultraviolet microscopy. Results from controlled crosses clearly showed the presence of two groups of trees, where intergroup crosses were compatible but intragroup crosses were incompatible. A sporophytic, diallelic, one-locus incompatibility system was inferred. Limited failure of the incompatibility mechanism was found (approximately 1% of crosses) for both selfs and intragroup crosses. Whereas most authors previously described C. alliodora as a homostyle, measurement of floral traits and study of their relationship to controlled crosses revealed a poorly defined variation in stigma size strongly associated with the incompatibility groups. The relatively undeveloped heteromorphy, coupled with a strong incompatibility mechanism, is of particular interest. The genus Cordia, in particular the Cerdanae, appears to offer fruitful ground for further investigation into aspects of the evolution and development of heterostyly. Key words: incompatibility, heterostyly, Cordia alliodora.
Structural aspects of Ascochyta blight of lentil
Authors: Roundhill S. J. , Fineran B. A. , Cole A. L. J. , Ingerfeld M.
Published: April 2008

Ascochyta fabae Speg. f.sp. lentis (Gossen et al. 1986) causes lesions on the leaf, stem, and pod of lentil (Lens culinaris Medik.), thereby reducing seed quality and yield. Lesion formation was studied in two cultivars, Laird and Invincible, using light and electron microscopy of intact and excised leaves and stems inoculated with spore suspension. Spores germinated usually within 6 h of inoculation and germ tubes grew for varying distances along the leaf surface before forming an appressorium, sometimes within less than 10 h. A penetration peg then either directly entered the underlying epidermal cell, or grew as a subcuticular hypha for a short distance before entering the cell. The first response of epidermal cells to presence of the fungus was an aggregation of cytoplasm abutting the site of infection. This was followed closely by deposition of a papilla. Some relatively thick papillae were seen at 29 h postinoculation. The fungus then grew into the papilla and formed an infection vesicle. In susceptible host cells, the protoplasm became necrotic before hyphae grew into the lumen of the cell from the infection vesicle. In more resistant cells, the infection vesicle often became surrounded by electron-dense wall material developed by the host. The fungus remained in susceptible epidermal cells for up to 4 days, amongst remnants of the protoplast, before spreading to the adjacent mesophyll. Hyphae grew into intercellular spaces of the mesophyll and remained there for 2 – 3 days before penetrating the cells. The mesophyll reacted in a similar way to infection as did the epidermis, with only host cells close to the fungus becoming affected. Cultivar Laird was found to be less susceptible to infection than cv. Invincible. At the structural level, the infection process was found to be similar except that in cv. Laird the infection vesicle more frequently became surrounded by electron-dense wall material formed by the host. In stem tissue of cv. Laird the middle lamella was also occasionally thickened with electron-dense material deposited on either side of it. After the degeneration of host tissue, pycnidia-bearing spores were formed 10 – 14 days after inoculation of the leaf. Key words: Ascochyta, lentil, ultrastructure, infection process.
Genetic variability and tradeoffs among reproductive traits in white clover (Trifolium repens)
Authors: Kahn B. , Silander Jr. J. A. , Reynolds H. L. , Cain M. L.
Published: April 2008

There is much spatial and temporal variation for reproductive output in white clover (Trifolium repens L.), yet little is known about the control of this variation or whether there exist tradeoffs among components of seed yield. To examine these issues, seed yield components and vegetative biomass were measured on replicates of seven white clover genotypes planted in a common garden plot. Significant genetic differences among clones were found for biomass and for five of seven reproductive characters, including number of inflorescences, number of florets per inflorescence, number of fruits per infructescence, number of (late-maturing) seed per fruit, and seed weight in early-maturing fruits. Thus, there is considerable potential for natural or artificial selection to act on vegetative and reproductive characters in white clover. In addition to these genetic effects, we observed temporal variation for number of florets per inflorescence, number of fruits per infructescence, and seed weight in late-maturing fruits. Finally, analyses of phenotypic, genetic, and microenvironmental correlation coefficients revealed few pairs of traits with significant negative correlations. This suggests that few tradeoffs in resource allocation patterns existed for the phenotypic characters examined. Key words: Trifolium repens, genetic variation, seed yield components, tradeoffs, phenotypic correlation, genetic correlation.
Atlantic Herring (Clupea harengus) Distributions in the Gulf of Maine – Scotian Shelf Area in Relation to Oceanographic Features
Authors: Sinclair M. , Iles T. D.
Published: April 2008

There are clear, temporally persistent patterns in the spatial distributions of Atlantic herring (Clupea harengus) at various life history stages. Three areas of potential importance for summer feeding and overwintering and one juvenile nursery area are described. In contrast, there are several well-defined spawning locations and larval distributional areas. The distributional patterns infer considerable between-population mixing at all phases of the life history except at spawning time itself and during the first several months of the larval phase. The life history distributions are interpreted in relation to tidally induced oceanographic features of the area. The specific locations of spawning and the associated larval distributions are interpreted to be a function of the location of physical features associated with "larval retention." The summer-feeding areas are associated with the location of tidally induced temperature fronts where plankton production is high. The larval distributional areas are argued to be occupied in spite of their particular plankton characteristics rather than because of them. The observed distributions are not consistent with some fisheries biology theories.
An Evaluation by Field Experiments of the McLay Model of Stream Drift
Authors: Larkin P. A. , McKone D. W.
Published: April 2008

The model of McLay (J. Fish. Res. Board Can. 27: 359–370) for describing the drift of stream organisms was tested in a variety of field experiments in which organisms were disturbed from the substrate and/or the natural drift was blocked. In each situation, appropriate corrections may be made for the catch of drift organisms by the sampling nets. Disturbed animals drifted at a rate much less than stream velocity. The logarithm of the distance travelled was a linear function of the logarithm of mean stream velocity and conformed to the McLay model. Similarly, the model adequately described experiments in which two disturbances were done simultaneously, when drift was blocked for a 2-h period, and when there was both disturbance and blockage. A more comprehensive version of the model was only partially successful in describing the drift at various distances downstream of a blockage sustained for 4 d, probably because of upstream migration of organisms through the substrate, spatial differences in the densities of animals in the substrate, or a reduction in drift rate at lower density in the substrate.
Age and Growth of the Sandbar Shark (Carcharhinus plumbeus) from the Western North Atlantic
Authors: Casey J. G. , Pratt Jr. H. L. , Stillwell C. E.
Published: April 2008

Age and growth of the sandbar shark (Carcharhinus plumbeus) was determined from rings in the vertebrae of 475 individuals, tagging data from 220 sharks at liberty for up to 17 yr, and length–frequency data from 2594 individuals. The oldest male sandbar aged in this study was 15 yr old and 154 cm fork length (FL); the oldest female was 21 yr old and 204 cm FL. The sexes grew at similar rates, 5.2–7.3 cm/yr. Females reached a larger adult size. Age to maturity was estimated at 13 yr in males and 12 yr in females. Tag returns indicated that sandbar sharks may live for over 30 yr. von Bertalanffy parameters for males are L∞ = 257, K = 0.0501, t0 = −4.5 and for females are L∞ = 299, K = 0.040, t0 = −4.9.
Predicting Inshore Whale Abundance — Whales and Capelin off the Newfoundland Coast
Authors: Whitehead Hal , Carscadden J. E.
Published: April 2008

Inshore abundance of baleen whales along the Newfoundland coasts changed considerably during the period 1973–83. In particular, large numbers of humpbacks were present along the northeast coast each summer between 1977 and 1980. This influx led to entrapment of whales in fishing gear. Counts of humpback (Megaptera novaeangliae), finback (Balaenoptera physalus), and minke (Balaenoptera acutorostrata) whales during standard surveys along the coast are used as indices of inshore abundance, and are related to the year-class strengths of capelin (Mallotus villosus), their major food in the Newfoundland region. Whales are found inshore when there are few immature capelin offshore. Minke whale distributions seem more closely related to the abundance of 1- to 2-yr-old, immature capelin, but humpback and finback whales are found inshore with low abundances of 2- to 3-yr-old, mainly immature capelin. We suggest that estimates of capelin year-class strength predicted from abiotic variables can be used to predict inshore whale abundance, at least 1 yr in advance. The extreme influx of humpbacks of the late 1970s is unlikely to recur in the short term. The analysis suggests that finback populations in the area are declining.
Interaction Between Stock Area, Stock Abundance, and Catchability Coefficient
Authors: Winters G. H. , Wheeler J. P.
Published: April 2008

The relationship between commercial catch-rates and population density upon which many stock assessment models depend assumes that stock area (A) is constant and independent of population abundance. Starting from a theoretical demonstration that the catchability coefficient (q) is inversely proportional to A, we establish the empirical basis of this relationship through comparisons of q and A of various Northwest Atlantic herring (Clupea harengus harengus) stocks and, in more detail, for Fortune Bay herring. For these stocks the relationship was of the form q = cA−b. For Atlantic herring stocks, levels of b were in excess of 0.80. In Fortune Bay herring, reductions in abundance were accompanied by proportional reductions in A, which in turn was inversely correlated with changes in q. School size, measured as catch per set, also declined as population levels declined but the change was not proportional. Published findings indicate that pelagic stocks in particular, and fish stocks in general, exhibit a common response of reductions in A with interactive increases in the q during periods of rapid population decline. We conclude that the conventional assumption of a constant stock area is usually violated due to the systematic interaction between A and population abundance which is reflected in an inverse relationship between stock abundance and q. Calibration of sequential population models should therefore be restricted to research vessel data collected in a standard manner and covering the distributional area of the stock.
Microstructure of Fish Otoliths
Authors: Campana Steven E. , Neilson John D.
Published: April 2008

Otolith microstructure examination has found an increasing number of applications in recent years. However, few workers have critically assessed the assumptions upon which the age and growth inferences are based or considered the potential for environmental modification of microstructural features. This paper reviews present applications and their assumptions and suggests future directions. Particular attention is given to the premises that the frequency of increment formation is constant and that the width of increments is proportional to fish growth. A hypothesis of increment formation is presented which appears consistent with the numerous and often conflicting studies reported to date. The presence of an endogenous circadian rhythm of increment formation is invoked, entrained by photoperiod, but susceptible to modification by other cyclic environmental variables. Increments formed as a result of the circadian rhythm (once per 24 h) may be induced by different processes than those induced through the action of environmental cues (often > 1 per 24 h), thus explaining apparent morphological differences in increment structure noted by some workers. Temperature fluctuations appear to be a primary source of subdaily increments and are a potential source of error in otolith interpretation.
Back-Calculation of Fish Lengths Based on Proportionality between Scale and Length Increments
Authors: Ricker William E.
Published: April 2008

The assumption underlying linear back-calculation offish lengths (L) from scale measurements (S) is that annual increments of length (ΔL) are proportional to annual increments between the annuli on scales (ΔS) for each fish–scale combination. A sample from a fish population that provides measurements of fish length and scale radius at time of collection should be symmetrical transversely to its central axis when plotted with an absolute slope of 45°; if not, it can be made symmetrical by either of two easy methods. The slope of the central axis can be estimated using either an arithmetic mean regression or (preferably) the geometric mean regression; either should be made to pass through the centroid of the whole sample. Average lengths at each age are unbiased if computed from average annulus distances using one of the above symmetrical statistics whereas biased estimates are obtained using either of the ordinary regressions between S and L, especially when part of the range of ages (older than 0) is missing at either end of the sample. Lengths of individual fish can be back-calculated throughout their life by using either the Whitney–Carlander or (preferably) the Fraser–Lee procedure, with the fixed parameter estimated from a symmetrical regression line.
Accounting for individual variability in the von Bertalanffy growth model
Authors: Wang Yoy-Gan , Thomas Mervyn R.
Published: April 2008

Estimation of von Bertalanffy growth parameters has received considerable attention in fisheries research. Since Sainsbury (1980, Can. J. Fish. Aquat. Sci. 37: 241–247) much of this research effort has centered on accounting for individual variability in the growth parameters. In this paper we demonstrate that, in analysis of tagging data, Sainsbury's method and its derivatives do not, in general, satisfactorily account for individual variability in growth, leading to inconsistent parameter estimates (the bias does not tend to zero as sample size increases to infinity). The bias arises because these methods do not use appropriate conditional expectations as a basis for estimation. This bias is found to be similar to that of the Fabens method. Such methods would be appropriate only under the assumption that the individual growth parameters that generate the growth increment were independent of the growth parameters that generated the initial length. However, such an assumption would be unrealistic. The results are derived analytically, and illustrated with a simulation study. Until techniques that take full account of the appropriate conditioning have been developed, the effect of individual variability on growth has yet to be fully understood.
Probability-based short term design of soil slopes
Authors: Tang W. H. , Yucemen M. S. , Ang A. H.-S.
Published: April 2008

Earth slopes are generally designed in an environment characterized by numerous uncertainties, stemming from limited sampling efforts on soil strata with variable soil properties, amplified further by the discrepancy between in situ and laboratory measured soil strengths. Additional uncertainties are also introduced from various simplifying assumptions and idealizations that are necessary for a practical mathematical analysis of stability.The uncertainties involved in the short-term stability of soil slopes have been evaluated from an extensive literature survey. A procedure for developing design of earth slopes based on a permissible risk is formulated whereby experience, published research results, experimental test data and judgement can be consistently incorporated in the evaluation of uncertainties and reliability of a given design. An example of slope design is presented to illustrate the proposed risk-based design method.
Constitutive relations for volume change in unsaturated soils
Authors: Fredlund D. G. , Morgenstern N. R.
Published: April 2008

Volume change constitutive relations for unsaturated soils are proposed from a semi-empirical standpoint. One equation describes the deformation of the soil structure and a second equation defines the volume of water present in the element. Each equation can be viewed as a three-dimensional surface with two independent stress state variables forming the abscissas.Uniqueness is tested by measuring volume changes resulting from stress changes in two orthogonal directions and comparing predicted and measured volume changes resulting from a stress change in a third direction. Samples of undisturbed Regina Clay and compacted kaolin showed good agreement between the predicted and measured volume changes for monotonic deformation of the soil structure. The agreement was not as close for the water phase. The variation was attributed to difficulties in measuring water volume changes over a long period of time. The laboratory results indicate that the proposed constitutive equations are of the appropriate form for use in engineering practice.
Seepage control in tailings dams
Authors: Mittal Hari K. , Morgenstern Norbert R.
Published: April 2008

It is common for the rate of seepage through a tailings embankment to be estimated on the basis of a conventional flow net analysis assuming steady seepage conditions. Moreover an impervious seal is generally recommended against the upstream face of the dam to minimize seepage flow through the sand embankment. This study shows that, due to rapid rates of placing, slimes can exist in an under-consolidated state. Field measurements are cited in support of the theory and the implications of under-consolidated slimes in the pond are discussed in detail. Procedures to analyse the utility of an upstream seal are also discussed and design examples reflecting actual operating conditions are given.
A theory of soil sedimentation
Authors: McRoberts E. C. , Nixon J. F.
Published: April 2008

The sedimentation behaviour of thick dispersions of mineral grains and water, a process that can be called hindered settling, is of some interest in geotechnical practice. This study draws attention to the existence of the phenomenon, investigates the laws governing the settling behaviour of dispersions and provides experimental verification of the theory.
A model for the runout analysis of rapid flow slides, debris flows, and avalanches
Authors: Hungr Oldrich
Published: April 2008

Runout analyses are used for risk assessment and design of remedial measures against rapid landslides such as debris flows, debris avalanches, rockslide avalanches, large-scale liquefaction failures, and slides of fill and mining waste. A continuum model has been developed to simulate the characteristics of these phenomena. The model is based on a Lagrangian solution of the equations of motion and allows the selection of a variety of material rheologies, which can vary along the slide path or within the slide mass. It also allows for the internal rigidity of relatively coherent slide debris moving on a thin liquefied basal layer. The effects of lateral confinement are accounted for in a simplified manner. The model is shown to compare favourably with results of controlled laboratory experiments and other analytical tools for several different materials and problem configurations. Examples of the practical use of the model to predict the runout of coal mine waste flow slides and flows of liquefied granular tailings are presented. Key words : landslides, dynamic analysis, runout prediction, debris flows, debris avalanches, flow slides.
A finite layer technique for modelling complex landfill history
Authors: Rowe R. Kerry , Booker John R.
Published: April 2008

A semianalytical (finite layer) technique for modelling contaminant transport from a landfill for relatively complex conditions is presented. The theory allows consideration of multiple units such as secondary leachate collection systems, hydraulic control layers, or aquifers, which can be used to remove contaminant from below the landfill. The theory allows consideration of time-varying properties of the system (e.g., shutdown or failure of the primary and (or) secondary leachate collection systems after a specified period of time). It also allows consideration of complex source concentration histories with time, including the increase in concentration with time, constant source concentration for a period of time, and decrease in concentration as mass is removed from the system. The application of the technique is illustrated with an example. Key words : contaminant impact, analysis, landfill design, clay, fractures, diffusion, failure, groundwater.
Field observations of frost action in intact and weathered Champlain Sea clay
Authors: Konrad J.-M. , Roy M. , Rochelle P. La , Leroueil S. , Bergeron G.
Published: April 2008

This paper presents the results of a field study on frost action in sensitive Saint–Alban clay both in an intact state, never subjected to any freeze–thaw cycles, and in its weathered state, corresponding to thousands of freeze–thaw cycles. It appears that intact clay is highly frost susceptible and displays frost heave of about 20 cm for the 1989–1990 freezing season. The segregation potential of intact clay ranges between 425 and 550 × 10−5 mm2/(s∙ °C), while that of the crust is only about 40 to 50 × 10−5 mm2/(s∙ °C). In the field, destructured clay displayed a segregation potential value of 265 × 10−5 mm2/(s∙ °C). Loss of bearing capacity during thaw of frozen intact clay is substantial, with reduction in undrained strength from 10 to 2.5 kPa. Key words : sensitive clays, frost heave, field, instrumentation, segregation potential.
Lantern effects on pressuremeter shear modulus in sand
Authors: Cunha R P
Published: April 2008

Self-boring pressuremeter tests are presently used to assess in situ deformation characteristics of sand. To reach the desire testing depth with minimum disturbance, a consistent self-boring procedure is commonly adopted. High lateral stresses developed during insertion of the pressuremeter has led, in the past, to the adoption of a lantern to cover and protect the expandable rubber membrane section of the probe. This note summarizes an investigation of the influence of different lantern designs on the predicted shear modulus of the sand. Distinct steel strip lanterns were used and compared with the standard lantern used in the Camkometer. It is demonstrated that the interstrip friction of the steel lantern can affect the shear modulus from unloadreload loops of the test. The importance of this investigation is viewed as more practical than technical, since steel lanterns are less expensive, quicker, and simpler to construct than the standard Camkometer lantern.

Key words: self-boring procedure, lanterns effect, unloadreload, interstrip friction, shear modulus, sand.
Frustum confining vessel for testing model piles
Authors: Horvath Robert G , Stolle Dieter
Published: April 2008

A cone-shaped vessel, a frustum, has been developed for testing model piles. The magnitude of the confining stresses in the soil within the vessel can be controlled by applying pressure to a piston in the bottom of the device. A series of continous cone penetration tests was performed to determine approximate stress distributions with depth along the frustum axis. The penetration test results indicated that vertical stress within the soil mass increased with depth from zero at the top of the soil to a maximum value at the bottom, which is controlled by the stress applied to the bottom piston. Finite element analyses, which were carried out to establish stress patterns within the frustum confining vessel, confirmed the results obtained from the physical testing. This study demonstrates that the new confining vessel enables physical testing of small-scale model foundations under soil mass conditions that more closely reflect the in situ stress conditions encountered with full-scale foundations under in-service conditions.

Key words: cone penetration resistance, confining stress, finite element analyses, frustum confining vessel, small-scale model testing, stress distribution.
Coupled diffusionfabric-flow phenomena: an effective stress analysis
Authors: Fam M , Santamarina J C
Published: April 2008

Concentration diffusion, fluid flow and fabric changes are coupled phenomena in fine soils. Indeed, experimental results previously presented by the authors showed the presence of a pressure front advancing ahead of the diffusing high-concentration front in bentonite and kaolinite specimens. This note presents a simple analysis of diffusionfabric-flow coupling, based on elementary double-layer repulsion and attraction. Model predictions adequately agree with experimental data. High specific surface, high initial void ratio, and low initial pore-fluide concentration increase the sensitivity of soils to changes in pore-fluid concentration and enhance the potential development of pore pressure fronts.

Key words: coupling, diffusion, clay, pore pressure, interparticle forces.
Biogeoclimatic classification system for hydrologic interpretations
Authors: Winkler R. D. , Rothwell R. L.
Published: April 2008

The purpose of this study was to assess the utility of the biogeoclimatic land-classification system for hydrologic interpretations. It was hypothesized that hydrologic recharge and discharge areas could be identified in a watershed using biogeoclimatic survey data. An intensive biogeoclimatic survey was conducted in Tri Creeks Experimental Watershed, which is located 70 km southwest of Edson, Alberta. Plant associations identified by the survey were evaluated as either recharge or discharge areas based on species composition, slope position, relative water yield, soil-water storage, and peak-flow estimates based on a modified form of the rational equation. The biogeoclimatic survey identified two distinct plant associations. Each plant association was characterized by four to six indicator species. Genera for plant association A included Geum, Salix, and Betula, and those for plant association B included Arnica, Cornus, and Vaccinium. Plant association A was considered representative of discharge areas because of its location on lower slopes adjacent to stream channels, and the presence of plant species indicative of wet riparian habitats. Association B was judged a recharge area because of its location on upper slopes and the presence of plant species indicative of drier habitats. Simple water-balance calculations for each plant association further supported these interpretations. The greater relative water yield and soil-water content throughout the growing season for association A over association B were judged a reflection of its location in a discharge area. The prediction of peak flows, using the areal extent of association A in the rational equation, also supported its identification as a discharge area. The precision of prediction was low with estimated values exceeding actual values by 1–4 times. However, moderate to high levels of correlation between estimated peaks and actual peaks were observed for late-summer storms, and judged to demonstrate the importance of association A as a discharge area for storm flow.
Flowering in a jack pine seedling seed orchard increased by spraying with gibberellin A4/7
Authors: Cecich Robert A.
Published: April 2008

Jack pine (Pinusbanksiana Lamb.), in a 3-year-old orchard established with accelerated-growth seedlings, were sprayed with gibberellin A4/7 (GA4/7) in an Aromox–ethanol solution during the 1981 growing season. Seven treatment periods were evaluated: the entire growing season, shoot elongation, bud development, early (first half) and late (second half) shoot elongation, and early and late bud development. Three concentrations of GA4/7 (200, 400, and 600 mg•L−1) were applied in all combinations with treatment periods. Three treatments increased female flowering: 400 and 600 mg•L−1 GA4/7 sprayed the entire growing season and 600 mg•L−1 sprayed during bud development. The number of pollen clusters was increased by spraying 400 and 600 mg•L−1 GA4/7 during any treatment period except early shoot elongation and late bud development or during shoot elongation (400 mg•L−1 only). The 200 mg•L−1 GA4/7 increased pollen clusters only if sprayed during early bud development or the entire growing season. The percentage of trees bearing pollen increased with all concentrations of GA4/7. The 1982 shoot growth of trees sprayed in 1981 during shoot elongation or the entire growing season (all GA4/7 levels pooled) was significantly less than control-tree growth or that of trees in the other treatment periods. The best treatment for increasing both male and female strobili was 600 mg•L−1 GA4/7 sprayed during bud development.
Isozyme variation in Pinusmonticola
Authors: Steinhoff R. J. , Joyce D. G. , Fins L.
Published: April 2008

Seeds from 28 stands representing most of the range of Pinusmonticola Dougl. were analyzed for electrophoretically demonstrable variation in 10 proteins encoded by 12 genetic loci. On the average, 65% of the loci per stand were polymorphic, and expected heterozygosity of offspring was 18%. The populations could be assigned to two geographic groups, a broad northern one and a rather restricted southern one. The southern group consisted of populations from the Sierra Nevada and southern Cascade Mountains in northern California and from the Warner Mountains in south-central Oregon. These southern populations were similar to each other but all differed from those of the northern group in allelic frequency patterns for several isoenzymes. Across the northern part of the species' distribution (British Columbia, Washington, northern Oregon, Idaho, and Montana) differences among stands were minor and essentially random. Collections from stands in the central and southern Oregon Cascades and the Siskiyou Mountains of northwestern California were more nearly like the northern stands but exhibited some characteristics indicative of a transition area between the Sierra and northern types.