Defining Landscape Resistance Values in Least-Cost Connectivity Models for the Invasive Grey Squirrel: A Comparison of Approaches Using Expert-Opinion and Habitat Suitability Modelling

Least-cost models are widely used to study the functional connectivity of habitat within a varied landscape matrix. A critical step in the process is identifying resistance values for each land cover based upon the facilitating or impeding impact on species movement. Ideally resistance values would be parameterised with empirical data, but due to a shortage of such information, expert-opinion is often used. However, the use of expert-opinion is seen as subjective, human-centric and unreliable. This study derived resistance values from grey squirrel habitat suitability models (HSM) in order to compare the utility and validity of this approach with more traditional, expert-led methods. Models were built and tested with MaxEnt, using squirrel presence records and a categorical land cover map for Cumbria, UK. Predictions on the likelihood of squirrel occurrence within each land cover type were inverted, providing resistance values which were used to parameterise a leastcost model. The resulting habitat networks were measured and compared to those derived from a least-cost model built with previously collated information from experts. The expert-derived and HSM-inferred least-cost networks differ in precision. The HSM-informed networks were smaller and more fragmented because of the higher resistance values attributed to most habitats. These results are discussed in relation to the applicability of both approaches for conservation and management objectives, providing guidance to researchers and practitioners attempting to apply and interpret a leastcost approach to mapping ecological networks.This project was funded by the Forestry Commission GB and the National School of Forestry at the University of Cumbria. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

The democratic production of political cohesion: partisanship, institutional sesign and life form

Online: 27 November 2018What binds a democratic society together? This would seem a well-rehearsed topic in modern political theory, but on closer scrutiny, it may appear less so. If we reformulate the question, it may become clearer why: what binds democratic society together? The emphasis on ‘democratic’ is the clue here. Much recent discussion on the cohesive force in democracies has been parasitic on other debates, such as that between cosmopolitans and communitarians on justice as the first virtue of society; that between nation-state-based and post-national views of contemporary politics or that about the cultural aspects of democratic citizenship as the glue that makes democracy work. All such views and debates tend to assume a somewhat ‘externalist’ perspective, so to speak, of the problem of cohesion in democracies. Cosmopolitans and liberal communitarians have argued over the relative importance of values and identity as the basis for the stability of a just society, whose legitimate political arrangements they generally agree must be democratic, so as to reflect the demands of equality and self-government. Disputes over whether the institutions of democracy still require the background conditions provided by the nation-state, with its consolidated networks of party system, solidarity, civil society organisations and public opinion formation, or whether similar conditions can be reproduced at a more trans- and post-national level, are very similar in scope to those between cosmopolitans and liberal communitarians. Both these disputes concern the social, institutional, ideal or identitarian pre-conditions of democracy, which help it to work with a modicum of stability, in so far as they guarantee the political cohesion of either the demos or the regime itself. Discussions over the quality and competence of citizenship look at democratic culture as an important condition for democratic institutions and procedures to function smoothly and effectively. Debates over the ‘civic culture’ in the 1960s and more recently on ‘social capital’ lay emphasis on a mixture of attitudes, practices, participation in associational networks and consolidated norms of sociability as formative components of democratic citizenship, on which the working of democratic institutions and rules depends. This suggests something more internal, or at least a virtuous circle between the culture and the institutions of democracy. But is democracy itself capable of producing political cohesion, and on what basis

The democratic production of political cohesion: partisanship, institutional design and life form

This is the author accepted manuscript. The final version is available from Springer via the DOI in this record

Effect of Folic Acid and Betaine Supplementation on Flow-Mediated Dilation: A Randomized, Controlled Study in Healthy Volunteers

OBJECTIVES: We investigated whether lowering of fasting homocysteine concentrations, either with folic acid or with betaine supplementation, differentially affects vascular function, a surrogate marker for risk of cardiovascular disease, in healthy volunteers. As yet, it remains uncertain whether a high concentration of homocysteine itself or whether a low folate status—its main determinant—is involved in the pathogenesis of cardiovascular disease. To shed light on this issue, we performed this study. DESIGN: This was a randomized, placebo-controlled, double-blind, crossover study. SETTING: The study was performed at Wageningen University in Wageningen, the Netherlands. PARTICIPANTS: Participants were 39 apparently healthy men and women, aged 50–70 y. INTERVENTIONS: Participants ingested 0.8 mg/d of folic acid, 6 g/d of betaine, and placebo for 6 wk each, with 6-wk washout in between. OUTCOME MEASURES: At the end of each supplementation period, plasma homocysteine concentrations and flow-mediated dilation (FMD) of the brachial artery were measured in duplicate. RESULTS: Folic acid supplementation lowered fasting homocysteine by 20% (−2.0 μmol/l, 95% confidence interval [CI]: −2.3; −1.6), and betaine supplementation lowered fasting plasma homocysteine by 12% (−1.2 μmol/l; −1.6; −0.8) relative to placebo. Mean (± SD) FMD after placebo supplementation was 2.8 (± 1.8) FMD%. Supplementation with betaine or folic acid did not affect FMD relative to placebo; differences relative to placebo were −0.4 FMD% (95%CI, −1.2; 0.4) and −0.1 FMD% (−0.9; 0.7), respectively. CONCLUSIONS: Folic acid and betaine supplementation both did not improve vascular function in healthy volunteers, despite evident homocysteine lowering. This is in agreement with other studies in healthy participants, the majority of which also fail to find improved vascular function upon folic acid treatment. However, homocysteine or folate might of course affect cardiovascular disease risk through other mechanisms

Weight-loss and exercise for communities with arthritis in North Carolina (we-can): design and rationale of a pragmatic, assessor-blinded, randomized controlled trial

Background: Recently, we determined that in a rigorously monitored environment an intensive diet-induced weight loss of 10% combined with exercise was significantly more effective at reducing pain in men and women with symptomatic knee osteoarthritis (OA) than either intervention alone. Compared to previous long-term weight loss and exercise trials of knee OA, our intensive diet-induced weight loss and exercise intervention was twice as effective at reducing pain intensity. Whether these results can be generalized to less intensively monitored cohorts is unknown. Thus, the policy relevant and clinically important question is: Can we adapt this successful solution to a pervasive public health problem in real-world clinical and community settings? This study aims to develop a systematic, practical, cost-effective diet-induced weight loss and exercise intervention implemented in community settings and to determine its effectiveness in reducing pain and improving other clinical outcomes in persons with knee OA. Methods/Design: This is a Phase III, pragmatic, assessor-blinded, randomized controlled trial. Participants will include 820 ambulatory, community-dwelling, overweight and obese (BMI ≥ 27 kg/m2) men and women aged ≥ 50 years who meet the American College of Rheumatology clinical criteria for knee OA. The primary aim is to determine whether a community-based 18-month diet-induced weight loss and exercise intervention based on social cognitive theory and implemented in three North Carolina counties with diverse residential (from urban to rural) and socioeconomic composition significantly decreases knee pain in overweight and obese adults with knee OA relative to a nutrition and health attention control group. Secondary aims will determine whether this intervention improves self-reported function, health-related quality of life, mobility, and is cost-effective. Discussion: Many physicians who treat people with knee OA have no practical means to implement weight loss and exercise treatments as recommended by numerous OA treatment guidelines. This study will establish the effectiveness of a community program that will serve as a blueprint and exemplar for clinicians and public health officials in urban and rural communities to implement a diet-induced weight loss and exercise program designed to reduce knee pain and improve other clinical outcomes in overweight and obese adults with knee OA