Tree species diversity interacts with elevated CO2 to induce a greater root system response

As a consequence of land use change and the burning of fossil fuels, atmospheric concentrations of CO2 are increasing and altering the dynamics of the carbon cycle in forest ecosystems. In a number of studies using single tree species, fine root biomass has been shown to be strongly increased by elevated CO2. However, natural forests are often intimate mixtures of a number of co-occurring species. To investigate the interaction between tree mixture and elevated CO2, Alnus glutinosa, Betula pendula and Fagus sylvatica were planted in areas of single species and a three species polyculture in a free-air CO2 enrichment study (BangorFACE). The trees were exposed to ambient or elevated CO2 (580 µmol mol-1) for four years. Fine and coarse root biomass, together with fine root turnover and fine root morphological characteristics were measured. Fine root biomass, and morphology responded differentially to elevated CO2 at different soil depths in the three species when grown in monocultures. In polyculture, a greater response to elevated CO2 was observed in coarse roots to a depth of 20 cm, and fine root area index to a depth of 30 cm. Total fine root biomass was positively affected by elevated CO2 at the end of the experiment, but not by species diversity. Our data suggest that existing biogeochemical cycling models parameterised with data from species grown in monoculture may be underestimating the belowground response to global change.

Fine-root turnover rates of European forests revisited: an analysis of data from sequential coring and ingrowth cores

Background and Aims Forest trees directly contribute to carbon cycling in forest soils through the turnover of their fine roots. In this study we aimed to calculate root turnover rates of common European forest tree species and to compare them with most frequently published values. Methods We compiled available European data and applied various turnover rate calculation methods to the resulting database. We used Decision Matrix and Maximum-Minimum formula as suggested in the literature. Results Mean turnover rates obtained by the combination of sequential coring and Decision Matrix were 0.86 yr−1 for Fagus sylvatica and 0.88 yr−1 for Picea abies when maximum biomass data were used for the calculation, and 1.11 yr−1 for both species when mean biomass data were used. Using mean biomass rather than maximum resulted in about 30 % higher values of root turnover. Using the Decision Matrix to calculate turnover rate doubled the rates when compared to the Maximum-Minimum formula. The Decision Matrix, however, makes use of more input information than the Maximum-Minimum formula. Conclusions We propose that calculations using the Decision Matrix with mean biomass give the most reliable estimates of root turnover rates in European forests and should preferentially be used in models and C reporting.

Competition and product survival in the UK car market

The paper examines the extent to which inter- and intra-firm competition influenced the survival of cars in the UK market between 1971 and 1998. It is shown that, while competition influenced product survival in all market segments within the UK car market, the nature of that competition differed between them. In the small family and large family car segments, intra-firm competition dominated inter-firm competition. In contrast, in the luxury/sports car segment only inter-firm competition conditions resulted in product survival. Evidence was also found that the luxury/sports car segment has grown more competitive over time and that firms marketing products in the family car segments have become considerably more successful at avoiding the effects of intra-firm competition.

Localization of calcitonin receptor-like receptor and receptor activity modifying protein 1 in enteric neurons, dorsal root ganglia, and the spinal cord of the rat

Calcitonin receptor-like receptor (CLR) and receptor activity modifying protein 1 (RAMP1) comprise a receptor for calcitonin gene related peptide (CGRP) and intermedin. Although CGRP is widely expressed in the nervous system, less is known about the localization of CLR and RAMP1. To localize these proteins, we raised antibodies to CLR and RAMP1. Antibodies specifically interacted with CLR and RAMP1 in HEK cells coexpressing rat CLR and RAMP1, determined by Western blotting and immunofluorescence. Fluorescent CGRP specifically bound to the surface of these cells and CGRP, CLR, and RAMP1 internalized into the same endosomes. CLR was prominently localized in nerve fibers of the myenteric and submucosal plexuses, muscularis externa and lamina propria of the gastrointestinal tract, and in the dorsal horn of the spinal cord of rats. CLR was detected at low levels in the soma of enteric, dorsal root ganglia (DRG), and spinal neurons. RAMP1 was also localized to enteric and DRG neurons and the dorsal horn. CLR and RAMP1 were detected in perivascular nerves and arterial smooth muscle. Nerve fibers containing CGRP and intermedin were closely associated with CLR fibers in the gastrointestinal tract and dorsal horn, and CGRP and CLR colocalized in DRG neurons. Thus, CLR and RAMP1 may mediate the effects of CGRP and intermedin in the nervous system. However, mRNA encoding RAMP2 and RAMP3 was also detected in the gastrointestinal tract, DRG, and dorsal horn, suggesting that CLR may associate with other RAMPs in these tissues to form a receptor for additional peptides such as adrenomedullin.

Tax principles, product differentiation and the nature of competition

We analyze the choice between the origin and destination principles of taxation when there is product differentiation and Bertrand competition. If taxes are redistributed to consumers and demand is linear the origin principle dominates the destination principle whatever the degree of product differentiation and extent of economic integration. With nonlinear demand the origin principle dominates if there is sufficient economic integration. When the social value assigned to tax revenue is higher than the private value, the destination principle dominates for intermediate values of product differentiation and economic integration. The same results are also shown to hold with Cournot competition.

Prizes for modernity in the provinces: The Arts Council’s 1950-1951 regional playwriting competition

As part of its contribution to the 1951 Festival of Britain, the Arts Council ran what can be seen in retrospect to be an important playwriting competition. Disregarding the London stage entirely, it invited regional theatres throughout the UK to put forward nominations for new plays within their repertoire for 1950-1951. Each of the five winning plays would receive, what was then, the substantial sum of £100. Originality and innovation featured highly amongst the selection criteria, with 40 per cent of the judges’ marks being awarded for “interest of subject matter and inventiveness of treatment”. This article will assess some of the surprising outcomes of the competition and argue that it served as an important nexus point in British theatrical historiography between two key moments in post-war Britain: the first being the inauguration of the Festival of Britain in 1951, the other being the debut of John Osborne’s Look Back in Anger in May 1956. The article will also argue that the Arts Council’s play competition was significant for two other reasons. By circumventing the London stage, it provides a useful tool by which to reassess the state of new writing in regional theatre at the beginning of the 1950s and to question how far received views of parochialism and conservatism held true. The paper will also put forward a case for the competition significantly anticipating the work of George Devine at the English Stage Company, which during its early years established a reputation for itself by heavily exploiting the repertoire of new plays originally commissioned by regional theatres. This article forms part of a five year funded Arts and Humanities Research Council (AHRC) project, ‘Giving Voice to the Nation: The Arts Council of Great Britain and the Development of Theatre and Performance in Britain 1945-1994’. Details of the Arts Council’s archvie, which is housed at the Victoria & Albert Museum in London can be found at http://www.vam.ac.uk/vastatic/wid/ead/acgb/acgbf.html Keywords: Arts Council of Great Britain, regional theatre, playwriting, Festival of Britain, English Stage Company (Royal Court) , Yvonne Mitchell

Comparing hypotheses about competition in the food system

A procedure is presented for comparing hypotheses about competition that makes no parametric assumptions about cost and demand functions, can be implemented with a modicum of data, and relies on Bayesian comparisons of non-nested hypotheses. The methodology is applied to data on five of the major U.S. food industries

Soil injections of carbohydrates improve fine root growth of established urban trees

Four established mature tree species (Aesculus hippocastanum L., Betula pendula Roth., Primus avium L. and Quercus rohur L.) commonly planted in UK urban landscapes were subjected to soil injections of the carbohydrate sucrose at 25, 50 and 70g per litre of water. Fine root dry weight was recorded at month 5 following soil injections. Soil injections of sucrose significantly increased fine root dry weight compared to controls, however; growth responses were influenced by species and the concentration of sucrose applied. Results indicate soil injections of sucrose ≥ 50g litre of water may be able to improve root growth of established mature trees. Such a response is desirable as root damage following construction is a frequent problem encountered by established trees growing in UK towns and cities.

Measuring variation in potato roots in both field and glasshouse: the search for useful yield predictors and a simple screen for root traits

Aims Potatoes have an inadequate rooting system for efficient acquisition of water and minerals and use disproportionate amounts of irrigation and fertilizer. This research determines whether significant variation in rooting characteristics of potato exists, which characters correlate with final yield and whether a simple screen for rooting traits could be developed. Methods Twenty-eight genotypes of Solanum tuberosum groups Tuberosum and Phureja were grown in the field; eight replicate blocks to final harvest, while entire root systems were excavated from four blocks. Root classes were categorised and measured. The same measurements were made on these genotypes in the glasshouse, 2 weeks post emergence. Results In the field, total root length varied from 40 m to 112 m per plant. Final yield was correlated negatively with basal root specific root length and weakly but positively with total root weight. Solanum tuberosum group Phureja genotypes had more numerous roots and proportionally more basal than stolon roots compared with Solanum tuberosum, group Tuberosum genotypes. There were significant correlations between glasshouse and field measurements. Conclusions Our data demonstrate that variability in rooting traits amongst commercially available potato genotypes exists and a robust glasshouse screen has been developed. By measuring potato roots as described in this study, it is now possible to assess rooting traits of large populations of potato genotypes.

Military competition and the emergence of nationalism: putting the logic of political survival into historical context

This essay aims to make a contribution to the conversation between IR and nationalism literatures by considering a particular question: What is the relationship between interstate military competition and the emergence of nationalism as a potent force in world politics? The conventional wisdom among international security scholars, especially neorealists, holds that nationalism can be more or less treated like a “technology” that allowed states to extract significant resources as well as manpower from their respective populations. This paper underlines some of the problems involved with this perspective and pushes forward an interpretation that is based on the logic of political survival. I argue that nationalism’s emergence as a powerful force in world politics followed from the “mutation” and absorption of the universalistic/cosmopolitan republican ideas that gained temporary primacy in Europe during the eighteenth century into particularistic nationalist ideologies. This transformation, in turn, can be best explained by the French Revolution’s dramatic impacts on rulers’ political survival calculi vis-à-vis both interstate and domestic political challenges. The analysis offered in this essay contributes to our understanding of the relationship between IR and nationalism while also highlighting the potential value of the political survival framework for exploring macrohistorical puzzles.

Dispersal of soil-dwelling clover root weevil (Sitona lepidus Gyllenhal, Coleoptera: Curculionidae) larvae in mixed plant communities

Insect pests that have a root-feeding larval stage often cause the most sustained damage to plants because their attrition remains largely unseen, preventing early diagnosis and treatment. Characterising movement and dispersal patterns of subterranean insects is inherently difficult due to the difficulty in observing their behaviour. Our understanding of dispersal and movement patterns of soil-dwelling insects is therefore limited compared to above ground insect pests and tends to focus on vertical movements within the soil profile or assessments of coarse movement patterns taken from soil core measurements in the field. The objective of this study was to assess how the dispersal behaviour of the clover root weevil (CRW), Sitona lepidus larvae was affected by differing proportions of host (clover) and non-host (grass) plants under different soil water contents (SWC). This was undertaken in experimental mini-swards that allowed us to control plant community structure and soil water content. CRW larval survival was not affected either by white clover content or planting pattern or SWC in either experiment; however, lower clover composition in the sward resulted in CRW larvae dispersing further from where they hatched. Because survival was the same regardless of clover density, the proportion of infested plants was highest in sward boxes with the fewest clover plants (i.e. the low host plant density). Thus, there is potential for clover plants over a larger area to be colonised when the clover content of the sward is low.

Competition for land

A key challenge for humanity is how a future global population of 9 billion can all be fed healthily and sustainably. Here, we review how competition for land is influenced by other drivers and pressures, examine land-use change over the past 20 years and consider future changes over the next 40 years. Competition for land, in itself, is not a driver affecting food and farming in the future, but is an emergent property of other drivers and pressures. Modelling studies suggest that future policy decisions in the agriculture, forestry, energy and conservation sectors could have profound effects, with different demands for land to supply multiple ecosystem services usually intensifying competition for land in the future. In addition to policies addressing agriculture and food production, further policies addressing the primary drivers of competition for land (population growth, dietary preference, protected areas, forest policy) could have significant impacts in reducing competition for land. Technologies for increasing per-area productivity of agricultural land will also be necessary. Key uncertainties in our projections of competition for land in the future relate predominantly to uncertainties in the drivers and pressures within the scenarios, in the models and data used in the projections and in the policy interventions assumed to affect the drivers and pressures in the future.