Elevational changes in woody vegetation along three streams in Washington County, Utah

Patterns of change in the woody vegetation (trees and shrubs) of the riparian communities of three streams draining the slopes of the Pine Valley Mountains in Washington County, Utah, were examined. Thirty-nine study sites were established adjacent to the streams along an elevational gradient where vegetation, plant population, and species data were taken. Vegetation and species patterns varied with respect to elevation and geographical location. Vegetation of the high- and low-elevation areas was distinctly different, while that of the mid-elevations was transitional to both. Geographical patterns showed a north-south transition in vegetation between the Mojave and Great Basin deserts. Size-class distribution curves for 11 tree species showed varying degrees of survival with respect to age and location. Root sprouting was highly important in the reproductive effort of six of the trees. Species distribution patterns followed transriparian and intrariparian gradients within the riparian community.     

Ultrastructure of synapses of the metacestode ofHymenolepis microstoma

Summary The ultrastructure of the synapses of the metacestode ofHymenolepsis microstoma is described. Many features observed are similar to those of many invertebrate and vertebrate synapses where mechanical strength is of importance. These observations indicate an early phylogenetic origin for this type of synapse.This work was supported by a grant from the University of New Brunswick Research Fund.     

Sustainable water resources management: River basin modelling and decision support framework

Sustainability is a key objective of water resources management and this paper describes a modelling and decision support framework that achieves this, illustrated by applications on the UK Thames and Mekong river basins. The decision support framework contains several modules, including an interactive user’s interface linked to a GIS, a geo-database, knowledge base, simulation models and optimization procedures. Based on the analysis of scenarios and proposed interventions, efficient modelling and optimization tools form a comprehensive integrated decision support framework for the analysis and operational management of water resources in the river basin, our emphasis has been on a practical implementation through careful screening of alternatives, consideration of the institutional framework and direct involvement of stakeholders in the decision making process. Operating in this environment is transparent, reproducible and auditable, securing the trust of all interested parties. This paper discusses its applications to water utilisation on the Mekong river basin and drought management of the Lower Thames stored reservoir system.     

A new interpretation of the sex determining mechanism of the European earwig,Forficula auricularia

Riassunto Osservazioni su femmine diForficula auricularia L. indicano che esse possiedono un solo cariotipo formato da 22 autosomi e da 2 cromosomiX. Sulla base di questo studio, suggeriamo che i maschi con 3 cromosomi sessuali sono del tipoXYY, e nonXXY come precedentemente ritenuto da varii autori. Ci sono maschiXY ₁t, XY₂, XY₂Y₂ e mosaiciXY ₂/XY₂Y₂ nella popolazione. Inoltre viene dimostrato che solamente il più grande dei due cromosomi Y, che caratterizzano questa specie, viene accumulato nei maschi con un meccanismo multiple di cromosomi sessuali.

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Supported by a postgraduate award from the Commonwealth of Australia to G.C.W. and by Public Health Service Grant No. GM-07212 from the Division of General Medical Sciences, U.S. National Institutes of Health and by a grant from the Australian Research Grants Committee.     

Vascular reactivity in hypertension: Altered effect of ouabain

Summary Ouabain inhibits the relaxing effect of Ca²⁺ (but not of Mn²⁺) on contractile responses in tail artery strips isolated from spontaneously hypertensive and normotensive rats. The magnitude of ouabain inhibition was greater in vascular strips from hypertensive rats suggesting a significant difference in basic membrane function in hypertensive vascular smooth muscle.These studies were supported by National Heart, Lung, and Blood Institute grants HL-03765 and HL-18575-02-03. R.C. Webb is a Postdoctoral Research Fellow of the Michigan Heart Association.