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Coppice systems are amongst the earliest forms of woodland management known, and on some sites, their use has been documented for centuries. Distinctive assemblages of plants and animals are associated with such systems and are highly valued in nature conservation terms. The richness of such assemblages, and conversely, the species that do not thrive under coppice, are linked to the alternation of relatively short light and dark phases, and the juxtaposition of stands at different stages in the coppice cycle. Vascular plants in the ground flora, invertebrates of open glades and scrub, and small birds of the understorey may have become more abundant in coppice than they would have been under 'natural' forest conditions. By contrast, epiphytes dependent on mature trees and species of large-sized deadwood are less favoured by coppice management. Coppice systems developed to meet the local community needs. As social and economic conditions changed, so coppicing declined and the woods were transformed into high forest through neglect or deliberate management. High forests differ from coppice stands in their spatial and temporal dynamics, and consequently, in their wildlife, particularly with respect to their vertical structure pattern, extent of open space and young growth, spatial heterogeneity, tree and shrub composition, and browsing levels. Three issues for the conservation of biodiversity arise from these changes: (1) What priority and resources should be given to halting further decline, by maintaining coppice compared to allowing sites to develop with more 'natural' high forest structures and dynamics; will associated high-forest species recolonize? (2) If we restore coppice systems, will the species assemblages present in the past also recover, under current and future changes in environmental conditions; i.e is the transformation reversible under current environmental conditions? (3) Are there other ways in which 'coppice-associated' species might be maintained? We identify research gaps and proposals to address these issues. [ABSTRACT FROM AUTHOR]

Allogeneic thymus lobes rendered alymphoid by treatment with deoxyguanosine are not rejected in normal mice despite expression of class I and class II MHC antigens on donor cells. The results presented here show that the injection of as few as 10,000 cells from dendritic cell-enriched populations is followed by the rejection of deoxyguanosine-treated grafts. These findings support the notion that treated thymus grafts do not provoke rejection because they lack dendritic cells, which are destroyed by deoxyguanosine. [ABSTRACT FROM AUTHOR]

Recent studies of electron-irradiated copolymers of vinylidene fluoride and trifluoroethylene have demonstrated the potential for achieving a large electrostrictive response in these materials. Since the principal effect of the radiation is network formation, alternative methods of achieving improved electromechanical properties are available. In this letter, we use a two-solvent swelling technique to quantify the polymer-solvent interaction parameter for the copolymer networks. This enables determination of their crosslink densities, along with a measure of the degree of degradation accompanying radiolysis. Copolymer networks were then prepared chemically using organic peroxide. These networks were found to be similar to the radiation-crosslinked materials, both in the extent of degradation and with respect to the Curie temperature and crystalline melting behavior. The latter are crucial to the development of better electrostrictive properties. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents an abstract of the study by G. Buckley on postgraduate medical education in Scotland, discussed during the Association for Medical Education in Europe's (AMEE) 1995 conference in Athens, Greece.

Scions taken from felled, shaken or sound sweet chestnut trees (Castanea sativa Mill.) were grafted and grown for one year in a polythene tunnel in order to compare their responses to water and nutrient stresses. Phenological characteristics of the original trees were strongly reproduced in the grafts grown both in this controlled environment and later on in the field. Grafts originating from shaken trees flushed up to six days later, senesced earlier and produced larger spring vessels. Artificially imposed drought reduced stomatal densities by 5.6% and xylem vessel diameters by up to 35%. Fertiliser additions significantly increased stem increments and promoted earlier flowering, with hermaphrodite flowering filaments more common in grafts from shaken trees. It is considered that, because of their larger spring vessels, shaken trees may be more vulnerable to cavitation and therefore to drought, even though moisture stress is mitigated by some plasticity in earlywood vessel diameter. [ABSTRACT FROM AUTHOR]

Provides information on the 1998 Annual Scientific Meeting of the Association for the Study of Medical Education. Theme of the meeting; Highlights of the meeting; Presenters and lecturers of the event.

1. Although application of fertilizers and pesticides to farmland is known to impact non-target organisms in adjacent semi-natural habitats, little is known of the impact on woodland understorey communities, which have considerable conservation significance in the arable landscapes of the UK and elsewhere in Europe. This study investigated the impacts of agrichemicals on several plant species typically found in ancient semi-natural communities. 2. Six species of woodland plants were exposed to the herbicide glyphosate at concentrations equivalent to those measured in spray drift trials (1–25% of the full application rate) in short-term greenhouse and long-term field experiments. Fertilizer was applied to half of the plants at a concentration likely to be seen in overspread situations (70 kg ha−1 year−1). The distribution of the same species was surveyed in woodland margins adjacent to fields with high, medium and low agrichemical inputs. 3. In both greenhouse and field experiments, herbicide treatments at drift concentrations caused increased mortality, reduced biomass and reduced fecundity in all species, although to differing degrees. The threshold of sensitivity to glyphosate was as low as 1% of the median field application rate for the most sensitive species. Fertilizer treatment affected resource partitioning in Carex remota and Galium odoratum and reduced the fecundity of G. odouratum. 4. In field surveys, the abundance of the most sensitive species was highest in woodland margins adjacent to fields with low agrichemical inputs and lowest beside high-input farmland. These differences were seen at least 4 m into woodland margins but were not found at 10 m. 5. Synthesis and applications. There was considerable agreement between the short-term greenhouse and long-term field experiments, although long-term impacts may have been underestimated in the former. Adverse impacts of pesticide drift have been demonstrated to affect a variety of plants of woodland margins bordering farmland. Differences in the distribution of species most sensitive to herbicide extend to at least 4 m into woodland margins. We recommend the adoption of no-spray buffer zones of at least 5 m to protect the majority of woodland species from the impacts of agrichemicals applied to adjacent land. [ABSTRACT FROM AUTHOR]

By analyzing the angular correlations in scanning electron nanodiffraction patterns from a melt-spun Zr36Cu64 glass, the dominant local order was identified as icosahedral clusters. Mapping the extent of this icosahedral short-range order demonstrates that the medium-range order in this material is consistent with a face-sharing or interpenetrating configuration. These conclusions support results from atomistic modeling and a structural basis for the glass formability of this system. [ABSTRACT FROM AUTHOR]

Aims: Burkholderia cepacia is a Gram-negative bacterium associated with increasing morbidity and mortality and is readily transmitted among infected cystic fibrosis (CF) patients. The B. cepacia complex consists of five distinct subgroups, termed genomovars. A collection of 17 presumptive B . cepacia isolates, obtained from three national CF referral centres located in different geographical regions in Ireland, was studied. The aim of this study was to investigate these isolates using molecular subtyping protocols for evidence of genetic relationships and for the presence of antibiotic resistance-encoding class 1 integron structures. Methods and Results: Genomovar classifications were assigned to each isolate based on Hae III enzyme profiles of their recA locus. Genetic relationships among this collection were also assessed after restriction fragment length polymorphism (RFLP)-mediated analysis of the 16S rDNA locus and DNA amplification fingerprinting (DAF). The surface expression of the cable pilus gene (cblA ) may facilitate an early step in the infection process. All isolates were tested by amplification strategies for this marker. Burkholderia cepacia is known to be resistant to several antimicrobial agents. Resistance typing showed that the majority were resistant to three or more common antimicrobial agents. Five of the 17 isolates were resistant to sulphonamide, a characteristic linked with the presence of class 1 integrons. Gene cassettes containing β-lactamase (oxa ) and aminoglycoside acetyltransferase (aac (6′)-1a) encoding genes were identified by polymerase chain reaction amplification. Conclusions: Most of the isolates in this study were classified as genomovar III and were indistinguishable based on their corresponding 16S rDNA-RFLP profiles, whilst DAF further subtyped the collection. The cblA marker was identified in 47% of the isolates, many of which clustered in the genomovar III group. Class 1 integrons with recombined gene... [ABSTRACT FROM AUTHOR]