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Common ash (Fraxinus excelsior L.) is an important timber species that is widespread in broadleaved woodlands across Europe, where it is currently declining due to the fungal pathogen (Hymenoscyphus fraxineus (T. Kowal) Baral et al. 2014) causing ash dieback. Using the UK as our case study, we assess: (1) likely woodland composition following ash dieback and (2) choice of replacement species for production planting. The greatest impacts on woodland composition will occur where ash forms a larger proportion of the canopy. In such woodlands, larger gaps formed from the loss of ash, are likely to be filled by sycamore (Acer pseudoplatanus L.) and beech (Fagus sylvatica L.) under current climatic conditions and where there is little management intervention. Native woodland policy regarding sycamore and beech may need to be reviewed in UK-designated woodlands where these species are considered non-native. For actively managed production woodlands, 27 replacement tree species for ash are considered, some of these are non-native and present options for continuing production forestry objectives on former ash sites. An assessment of replacement species shows there is no single species that can substitute for the wide range of site conditions associated with the good growth of ash. In deciding to replace ash with another tree species, the decision on selection should be made based on particular site conditions and woodland objectives. [ABSTRACT FROM AUTHOR]

Determining statistical patterns irrespective of interacting agents (i.e. macroecology) is useful to explore the mechanisms driving population fluctuations and extinctions in natural food webs. Here, we tested four predictions of a neutral model on the distribution of community fluctuations ( CF) and the distributions of persistence times ( APT). Novel predictions for the food web were generated by combining (1) body size-density scaling, (2) Taylor's law and (3) low efficiency of trophic transference. Predictions were evaluated on an exceptional data set of plankton with 15 years of weekly samples encompassing c. 250 planktonic species from three trophic levels, sampled in the western English Channel. Highly symmetric non-Gaussian distributions of CF support zero-sum dynamics. Variability in CF decreased while a change from an exponential to a power law distribution of APT from basal to upper trophic positions was detected. Results suggest a predictable but profound effect of trophic position on fluctuations and extinction in natural communities. [ABSTRACT FROM AUTHOR]

Studies the growth and branching of Quercus robur in young plants grown from acorns collected at sites in Holland. Variability of the mean length of the growth units produced the flushes of growth; Absence of significant differences in height between origins after six months growth; Failure to produce branches on all trees or on all growth units.

The 1341 Ma old Spitskop Complex in South Africa is one of a series of intrusions of alkaline affinity, which were emplaced into the central Kaapvaal Craton over the time period 1·4-1·2 Ga. Spitskop contains calcite and dolomite carbonatite closely associated with pyroxenite, ijolite and nepheline syenite, and provides an ideal opportunity to study the petrogenetic relationships between alkaline silicate and carbonatite magmatism. The pyroxenites are not alkalic and are preserved as xenoliths within a plug-like intrusion of ijolite. Nepheline syenites are highly peralkaline, though not agpaiitic, and intrude the ijolites as a series of sheets. These units are cut by a plug of carbonatite composed of an incomplete marginal zone of calcite and dolomite-calcite carbonatite, and a larger central zone of ferroan dolomite carbonatite. Clinopyroxene compositions change systematically from diopside-rich compositions in the pyroxenites to aegirine-augite-hedenbergite in the ijolites to acmite-dominated compositions in the nepheline syenites. Whole-rock chemical data indicate, however, that the nepheline syenites and ijolites are unlikely to be related through fractional crystallization of any reasonable combination of their component minerals (clinopyroxene, nepheline, perthite) from a common parental magma. Low total rare earth element (REE) concentrations and flat to convex-up normalized patterns in the syenites contrast strongly with the steep, light REE (LREE)-enriched patterns in the ijolites. The silicate and carbonatite components differ markedly in their [epsilon]Sr-[epsilon]Nd compositions, the carbonatites having more depleted values ([epsilon]Sr -10 to +10; [epsilon]Nd -1 to -8) than the silicates ([epsilon]Sr 0 to +33; [epsilon]Nd -8 to -13). In addition, the calcite-rich carbonatites have more negative [epsilon]Nd (-6 to -8) than the dolomite carbonatites (-1 to -4). Contrasting isotopic compositions along with the geochemical variations within and between the silicates and carbonatites argue against them being derived from conjugate immiscible liquids. Instead, it is proposed that the carbonatites evolved from primitive carbonate liquids produced directly by low-degree melting of carbonated mantle peridotite. A preliminary model is presented to explain how mantle carbonatite melts can ascend through the mantle and into the crust. It is proposed that the silicate magmatic rocks associated with the carbonatite are produced by melting of enriched mantle lithosphere induced by the influx of deeper-sourced carbonatite melts. [ABSTRACT FROM PUBLISHER]

Electrical and tracer techniques were used to investigate the movement of Na+, K+ and Cl- through discs of a range of thicknesses cut from the root tissue of sugar beet, Beta vulgaris L. cv. Amono. At low external concentration the electrical resistance across a discs is less than that of an equivalent volume of solution. This does not appear to be due to a low resistance symplastic pathway but rather, to an enhanced concentration of cation in the apoplast. The resistance is proportional to the thickness of tissue. Although measurement of diffusion potential gives about 25 mV difference across the disc for a ten-fold change in cation concentration, there is little discrimination between K+ and Na+. The observed tracer kinetics of 86Rb through the disc are consistent with those of diffusion, with a coefficient of diffusion, D, of 0.19×10-9 m2 s-1 and a tissue partition coefficient, k, of 0.27 (or of 2.7 if referred to the cell wall phase only). 36Cl gives a similar value for D, but has a k reduced by a factor of 3.3, a result that is consistent with the diffusion potential observation. However, a much larger discrimination would have been expected from the chemically measured cation exchange capacity. [ABSTRACT FROM AUTHOR]

Provides information on the United Nations Commission on International Trade Law (UNCITRAL) Model Law on Cross-Border Insolvency. Importance of the endorsement of the Model Law by UNCITRAL; Role of INSOL International in the adoption of the project by UNCITRAL; Recognition and relief of a foreign proceeding in the Model Law.

Examines the passage of the first insolvency legislation in Vietnam in December 1993. Brief economic and political history of Vietnam; Background on the country's legal structure; Provisions of the bankruptcy law.

Festuca vivipara plantlets were collected from a site in the English Lake District at several dates during the summer and autumn 1976. Various germination tests showed that plantlets from the early harvests were non-viable, Viability increased towards the end of the growing season and, at the last harvest, approximately 90% of the plantlets were capable of germinating. Plantlets showed no innate dormancy. However, the majority of plantlets were not dehisced from the panicle and establishment was largely through the collapse of the culm. Seeds of the closely related species, F. ovina, dehisced in July and exhibited a low primary dormancy. This could be broken by stratification and was lost after 2-3 months dry storage. Plantlets retained a greater capacity than seed to germinate at low temperature (3°C) and field observations show that F. vivipara plantlets establish after culm collapse in the autumn whereas F. ovina seeds may not germinate until the following spring. However, plantlets were capable of surviving for at least 25 weeks in conditions of high relative humidity and low temperature in the laboratory, suggesting that they have the capacity to survive the winter if they do not reach a suitable substrate for establishment. [ABSTRACT FROM AUTHOR]

The nutrient content of Festuca vivipara (L.) Sm. plantlets from a site in the English Lake District were compared with that of seeds of the closely related species, F. ovina L. The almost linear increase in dry weight of plantlets throughout the growing season was associated with an increase in their mineral nutrient content derived from the parent plant. Their amino acid and soluble carbohydrate content also increased markedly with size. The relatively high levels of free amino acids and soluble carbohydrates in viable plant-lets contrasts with the generally low levels of these compounds usually found in mature seed of grasses. Viable plantlets contained three to four times the nutrient content of F. ovina seeds resulting principally from the larger dry weight of the plantlets. The growth and survival of plantlets is discussed in relation to the Success of vivipary as a method of re- production in arctic-alpine environments. [ABSTRACT FROM AUTHOR]

Seventy patients with RA were randomly allocated to either a Rheumatology Nurse Practitioner (RNP) or Consultant Rheumatologist (CR) clinic. They were seen on six occasions in 1 year. Effectiveness and safety were assessed by biochemical, clinical, psychological and functional variables; patient knowledge and satisfaction were measured by questionnaire. At week 0 the groups were well matched clinically and demographically. By week 48 significant improvements had occurred in plasma viscosity and articular index within both groups. In patients managed by the RNP, pain, morning stiffness, psychological status, patient knowledge and satisfaction had all improved significantly ( = 0.001; = 0.028; = 0.0005; <0.0001; <0.0001 respectively), improvements not mirrored by the CR cohort. Between group comparisons also showed significant differences by the end of the study. Compared to the CR patients, the RNP suffered from lower levels of pain (<0.05), had acquired greater levels of knowledge (<0.0001) and were significantly more satisfied with their care (<0.0001). [ABSTRACT FROM PUBLISHER]

There is much debate about whether carbonatite magmas are derived in ‘secondary’ fashion through the advent of liquid immiscibility operating in the crust on evolved nephelinitic magma, or whether they are derived in the mantle by direct partial melting of a carbonated peridotite. This paper briefly summarizes the εSr–εNd data fo carbonatites in general and evaluates the isotopic relationships between carbonatites and alkaline silicate rocks in several well-studied complexes from Africa. Available data for carbonatites younger than 200 Ma have a range in εSr–εNd that is less than that found in oceanic basalts despite the fact that carbonatites traverse lithospheres that ar much more complex than those in the oceans. By contrast, for the Napak, Kerimasi, Shombole, Dorowa, Shawa and Spitskop complexes the alkaline silicate rocks show greater variability and have more enriched εSr–εNd (higher εSr, lower εNd) values than their associated carbonatites. In general, the carbonatites hav isotopic compositions that are closer to the more primitive silicate rocks, such as melilitites a olivine nephelinites, than to more evolved nephelinites and phonolites. In the case of the Napak Complex the enriched component was introduced from the lower crust whereas for the Dorowa and Shawa complexes of SE Zimbabwe, the component was derived from the sub-continental lithospheric mantle. These relationships indicate that the carbonatites must have existed as discrete magmas i themantle and argue against a derivation by liquid immiscibility in the crust. Although a contrast i isotopic composition does not rule out an immiscibility relationship at mantle depths and early in the evolutionary history of a melilititic or nephelinitic magma, there is little experimental support for it. Existing experimental data indicate that immiscibility between carbonate an silicate liquids is favoured at low, crustal, pressures but that immiscibility is unlikely to occur in realistic mantle melts or their derivatives at mantle pressures. Many experimental data exist to show that magnesian carbonatite liquids form as the near-solidus melts of carbonated mantl peridotite at depths in excess of 75 km. We conclude that the calcitic and dolomitic carbonatite magma discussed in this paper are best considered as being derived from primary carbonatite magmas generated in the mantle by partial melting of carbonated peridotite. [ABSTRACT FROM AUTHOR]

A survey of 78 sites in southern England with approved management plans for restocking by natural regeneration was made during the summers of 1993 and 1994. The following features were recorded: species, stocking, canopy cover and seed-bearing potential of trees present in the overstorey; species and canopy cover of the understorey; ground cover; species, browsing damage, number and heights of tree seedlings. In general, sites were poorly stocked with overstorey trees having anaverage of 135 stems ha-1 and a mean canopy cover of 36 per cent. Similarly, the understoreys were poorly developed with an average cover of only 23 per cent. Twenty-nine species of tree were found in the overstorey, Quercus spp. and Fraxinus excelsior were the most common. Many of the stems present had poor seed-bearing potential.Cover of the ground flora often exceeded 75 per cent. Seedlings werepresent on most sites, with F. excelsior and Betula pendula being most abundant with mean seedling densities exceeding 10 000-ha-1. Most seedlings were <20 cm tall, few exceeded 120 cm. About 30 per cent of seedlings were browsed. The results are related to current guidance and the future prospects for use of natural regeneration. [ABSTRACT FROM AUTHOR]