The influence of larval density, food availability and habitat longevity on the life history and population growth rate of the midge Chironomus riparius

Despite long-standing interest in the forms and mechanisms of density dependence, these are still imperfectly understood. However, in a constant environment an increase in density must reduce per capita resource availability, which in turn leads to reduced survival, fecundity and somatic growth rate. Here we report two population experiments examining the density dependent responses under controlled conditions of an important indicator species, Chironomus riparius. The first experiment was run for 35 weeks and was started at low density with replicate populations being fed three different rations. Increased ration reduced generation time and increased population growth rate (pgr) but had no effect on survival, fecundity and female body weight in the first generation. In the second generation there was a six-fold increase in generation time, presumably due to the greatly reduced per capita resource availability as the estimated initial densities of the second generation were 300 times greater than the first. Juvenile survival to emergence, fecundity, adult body weight and pgr declined by 90%, 75%, 35% and 99%, respectively. These large between-generation effects may have obscured the effects of the threefold variation in ration, as only survival to emergence significantly increased with ration in the second generation. These results suggest that some chironomid larvae survive a reduction in resource availability by growing more slowly. In the ephemeral habitats sometimes occupied by C. riparius, the effects of population density may depend crucially on the longevity of the environment. A second experiment was therefore performed to measure pgr from six different starting densities over an eight-week period. The relationship between pgr and density was concave, viewed from above. At densities above 16 larvae per cm(2), less than 1% of the population emerged and no offspring were produced. Under the conditions of experiment 2 - an 8-week habitat lifespan carrying capacity was estimated as 8 larvae per cm(2).

The role of the Hellenic food safety authority in Greece: implementation strategies

During the last 15 years, a series of food scares and crises (BSE, dioxin. foot and mouth disease) have seriously under-mined public confidence in food producers and operators and their capacity to produce safe food. As a result, food safety has become a top priority of the European legislative authorities and systems of national food control have been tightened up and have included the establishment of the European Food Safety Authority. In Greece a law creating the Hellenic Food Safety Authority has been approved. The main objectives of this Authority are to promote the food security to consumers and inform them of any changes or any development in the food and health sector. The paper reviews the general structure of the current food control system in Greece. It describes the structure and the mission of the Hellenic Food Safety Authority and explains the strategy to carry out inspections and the analysis of the preliminary results of such inspections. Details are also given of the personnel training and certification and accreditation standards to be met by the Authority by the end of 2004. (c) 2005 Elsevier Ltd. All rights reserved.

Analytical and compositional aspects of isoflavones in food and their biological effects

This paper provides an overview of analytical techniques used to determine isoflavones (IFs) in foods and biological fluids with main emphasis on sample preparation methods. Factors influencing the content of IFs in food including processing and natural variability are summarized and an insight into IF databases is given. Comparisons of dietary intake of IFs in Asian and Western populations, in special subgroups like vegetarians, vegans, and infants are made and our knowledge on their absorption, distribution, metabolism, and excretion by the human body is presented. The influences of the gut microflora, age, gender, background diet, food matrix, and the chemical nature of the IFs on the metabolism of IFs are described. Potential mechanisms by which IFs may exert their actions are reviewed, and genetic polymorphism as determinants of biological response to soy IFs is discussed. The effects of IFs on a range of health outcomes including atherosclerosis, breast, intestinal, and prostate cancers, menopausal symptoms, bone health, and cognition are reviewed on the basis of the available in vitro, in vivo animal and human data.

An evaluation of the UK Food Standards Agency's salt campaign

Excessive salt intake is linked to cardiovascular disease and several other health problems around the world. The UK Food Standards Agency initiated a campaign at the end of 2004 to reduce salt intake in the population. There is disagreement over whether the campaign was effective in curbing salt intake or not. We provide fresh evidence on the impact of the campaign, by using data on spot urinary sodium readings and socio-demographic variables from the Health Survey for England over 2003–2007 and combining it with food price information from the Expenditure and Food Survey. Aggregating the data into a pseudo-panel, we estimate fixed effects models to examine the trend in salt intake over the period and to deduce the heterogeneous effects of the policy on the intake of socio-demographic groups. Our results are consistent with a previous hypothesis that the campaign reduced salt intakes by approximately 10%. The impact is shown to be stronger among women than among men. Older cohorts of men show a larger response to the salt campaign compared to younger cohorts, while among women, younger cohorts respond more strongly than older cohorts.

Exploring unanticipated consequences of strategy amongst stakeholder segments: the case of a European Revenue Service

This article applies FIMIX-PLS segmentation methodology to detect and explore unanticipated reactions to organisational strategy among stakeholder segments. For many large organisations today, the tendency to apply a “one-size-fits-all” strategy to members of a stakeholder population, commonly driven by a desire for simplicity, efficiency and fairness, may actually result in unanticipated consequences amongst specific subgroups within the target population. This study argues that it is critical for organisations to understand the varying and potentially harmful effects of strategic actions across differing, and previously unidentified, segments within a stakeholder population. The case of a European revenue service that currently focuses its strategic actions on building trust and compliant behaviour amongst taxpayers is used as the context for this study. FIMIX-PLS analysis is applied to a sample of 501 individual taxpayers, while a novel PLS-based approach for assessing measurement model invariance that can be applied to both reflective and formative measures is also introduced for the purpose of multi-group comparisons. The findings suggest that individual taxpayers can be split into two equal-sized segments with highly differentiated characteristics and reactions to organisational strategy and communications. Compliant behaviour in the first segment (n = 223), labelled “relationships centred on trust,” is mainly driven through positive service experiences and judgements of competence, while judgements of benevolence lead to the unanticipated reaction of increasing distrust among this group. Conversely, compliant behaviour in the second segment (n = 278), labelled “relationships centred on distrust,” is driven by the reduction of fear and scepticism towards the revenue service, which is achieved through signalling benevolence, reduced enforcement and the lower incidence of negative stories. In this segment, the use of enforcement has the unanticipated and counterproductive effect of ultimately reducing compliant behaviour.

An introduction to the ‘new’ politics of agriculture and food

The agricultural policy agenda has been broadened with farm policy issues now interlinking with other policy domains (food safety, energy supplies, environmental protection, development aid, etc.). New actors promoting values which sometimes conflict, or which are not always easily reconcilable, with those previously guiding agricultural policy have entered the broader agricultural and food policy domain. The studies of various new policy issues inter-linking with the agricultural policy domain included in this special issue show that value conflicts are addressed in different ways and thus result in inter-institutional coordination and conflict unfolding differently. Studies of inter-institutional policy making in the agricultural policy sector have the potential to contribute to theoretical developments in public policy analysis in much the same way as agricultural policy studies did in the past.

The changing nature of UK construction professional service firms

Professional services firms (PSFs) have been the subject of much attention in the literature in recent years, ranging across a number of distinct but related disciplines including economics, sociology, organization and management studies. Analysis has tended to concentrate on law and accounting firms in particular, and although there is a growing academic interest in construction/built environment professional services firms (CPSFs), these have received much less scrutiny. However, many of the changes taking place among PSFs – in particular, growth in firm size, moves towards external ownership and greater service/geographical diversification – are also taking place among the larger CPSFs. The CPSF sector is not especially well documented and there is little understanding of the motives for, and implications of, these changes in the firms, their clients and wider society. CPSFs are reviewed in the context of the more general PSF literature and a set of questions is posed for future research on CPSFs. These questions include the need to understand the implications of firm type on performance, the form of ownership that might confer the greatest financial benefits for different stakeholder groups, and the wider societal consequences of continuing growth in size and diversification of CPSFs.

Effects of phytate and minerals on the bioavailability of oxalate from food

Phytate and mineral cations are both considered as important dietary factors for inhibiting the crystallisation of calcium oxalate kidney stones in susceptible individuals. In this paper, the phytate and mineral composition of whole bran cereals (wheat, barley and oat) and legumes were determined together with their soluble and insoluble oxalate concentrations in order to investigate the effects on oxalate solubility. The oat bran sample had the highest soluble oxalate concentration at 79 ± 1.3 mg/100 g, while total and soluble oxalate concentrations in the food samples studied range from 33 to 199 mg/100 g and 14 to 79 mg/100 g, respectively. The phytate concentration was in the range from 227 to 4393 mg/100 g and the concentrations of cations were in the range 54–70 mg/100 g for calcium, 75–398 mg/100 g for magnesium, 244–1529 mg/100 g for potassium and 4–11 mg/100 g for iron. Soluble oxalate concentration did not increase in proportion to total oxalate, and the phytate concentration in all foods was sufficient to contribute to an increase in soluble oxalate concentration by binding calcium.

Key drivers of frontline employee generation of ideas for customer service improvement

Anchored in the service-dominant logic and service innovation literature, this study investigates the drivers of employee generation of ideas for service improvement (GISI). Employee GISI focuses on customer needs and providing the exact service wanted by customers. GISI should enhance competitive advantage and organizational success (cf. Berry et al. 2006; Wang and Netemeyer 2004). Despite its importance, there is little research on the idea generation stage of the service development process (Chai, Zhang, and Tan 2005). This study contributes to the service field by providing the first empirical evaluation of the drivers of GISI. It also investigates a new explanatory determinant of reading of customer needs, namely, perceived organizational support (POS), and an outcome of POS, in the form of emotional exhaustion. Results show that the major driver of GISI is reading of customer needs by employees followed by affective organizational commitment and job satisfaction. This research provides several new and important insights for service management practice by suggesting that special care should be put into selecting and recruiting employees who have the ability to read customer needs. Additionally, organizations should invest in creating work environments that encourage and reward the flow of ideas for service improvement

Opposing neural effects of naltrexone on food reward and aversion: implications for the treatment of obesity

Rationale: Opioid antagonism reduces the consumption of palatable foods in humans but the neural substrates implicated in these effects are less well understood. Objectives: The aim of the present study was to examine the effects of the opioid antagonist, naltrexone, on neural response to rewarding and aversive sight and taste stimuli. Methods: We used functional magnetic resonance imaging (fMRI) to examine the neural responses to the sight and taste of pleasant (chocolate) and aversive (mouldy strawberry) stimuli in 20 healthy volunteers who received a single oral dose of naltrexone (50 mg) and placebo in a double-blind, repeated-measures cross-over, design. Results: Relative to placebo, naltrexone decreased reward activation to chocolate in the dorsal anterior cingulate cortex and caudate, and increased aversive-related activation to unpleasant strawberry in the amygdala and anterior insula. Conclusions: These findings suggest that modulation of key brain areas involved in reward processing, cognitive control and habit formation such as the dorsal anterior cingulate cortex (dACC) and caudate might underlie reduction in food intake with opioid antagonism. Furthermore we show for the first time that naltrexone can increase activations related to aversive food stimuli. These results support further investigation of opioid treatments in obesity.

The distributional consequences of a fiscal food policy: evidence from the UK

The literature on fiscal food policies focuses on their effectiveness in altering diets and improving health, while this paper focuses on their welfare costs. A formal welfare economics framework is developed to calculate the combined individualistic and distributional impacts of a tax-subsidy. Distributional characteristics of foods targeted by a tax tend to be concentrated in lower-income households. Further, consumption of fruit and vegetables tends to be concentrated in higher-income households; therefore, a subsidy on such foods increases regressivity. Aggregate welfare changes that result from a fiscal food policy are found to range from an increase of 1.41 per cent to a reduction of 2.06 per cent according to whether a subsidy is included, the degree of inequality aversion, and whether substitution among foods is allowed.