Regulating coexistence of GM and non-GM crops without jeopardizing economic incentives

The ongoing debate about the coexistence of genetically modified (GM) and non-GM crops in the European Union (EU) mainly focuses on preventive measures needed to keep the adventitious presence of GM material in non-GM products below established tolerance thresholds, as well as on issues covering questions of liability and the duty to redress the incurred economic harm once adventitious mixing in non-GM products has occurred. By contrast, the interplay between the economic incentives and costs of coexistence has attracted little attention. The current overemphasis on the technical aspects and cost of coexistence over its economic incentives might lead EU policy-makers to adopt too stringent and rigid regulations on coexistence. Therefore, we argue for flexible coexistence regulations that explicitly take into account the economic incentives for coexistence. Our arguments provide a timely and important framework for EU policy-makers, who are currently struggling to implement coherent coexistence regulations in all member states.status: publishe

Bergmann and Converse Bergmann Latitudinal Clines in Arthropods: Two Ends of a Continuum?

Two seemingly opposite evolutionary patterns of clinal variation in body size and associated life history traits exist in nature. According to Bergmann's rule, body size increases with latitude, a temperature effect. According to the converse Bergmann rule, body size decreases with latitude, a season length effect. A third pattern causally related to the latter is countergradient variation, whereby populations of a given species compensate seasonal limitations at higher latitudes by evolving faster growth and larger body sizes compared to their low latitude conspecifics. We discuss these patterns and argue that they are not mutually exclusive because they are driven by different environmental causes and proximate mechanisms; they therefore can act in conjunction, resulting in any intermediate pattern. Alternatively, Bergmann and converse Bergmann clines can be interpreted as over- and undercompensating countergradient variation, respectively. We illustrate this with data for the wide-spread yellow dung fly, Scathophaga stercoraria (Diptera: Scathophagidae), which in Europe shows a Bergmann cline for size and a converse Bergmann cline (i.e., countergradient variation) for development time. A literature review of the available evidence on arthropod latitudinal clines further shows a patterned continuum of responses. Converse Bergmann clines due to end-of-season time limitations are more common in larger species with longer development times. Our study thus provides a synthesis to the controversy about the importance of Bergmann's rule and the converse Bergmann rule in natur

Costs of compliance with EU regulations and competitiveness of the EU dairy sector

The introduction of cross-compliance mechanism in the European Union with its 2003 CAPreform might affect the costs of production and thus competitiveness of the EU. Little evidence is available to asses the costs of compliance with regulations and it implication for trade. In this study a farm level competitiveness analysis of the impacts of the Nitrate Directive and the Identification & registration Directive focuses on the dairy sector in Germany, France, Italy, Netherlands and UK (within EU), and the US and New Zealand (outside EU). The findings from this study are integrated into a trade analysis which assesses the impact of compliance costs on competitiveness of the various trading nations in global trade. Representative farm studies were used as a basis for the cost increase calculations. Best-estimates of compliance are used from the existing literature and expert judgements. The negative impact of these measures (for nitrates, and animal identification and registration) on EU imports and exports are less than 3 percent. If a smaller increase in compliance takes place, these already relatively small trade impacts will be further diminished. When the standards for nitrate pollution taken by the US and New Zealand are taken into account along with full compliance assumption in all countries analysed, this would only slightly improve the EU exports. The trade impacts obtained when no changes are assumed to happen in key competitor countries can thus be argued as providing the upper bound of the likely trade impacts

Impact of infestation by parasitic weeds on rice farmers' productivity and technical efficiency in sub-Saharan Africa

Rice production is crucial for food security and income generation in sub-Saharan Africa. However, productivity and technical efficiency levels in rice production systems are severely constrained by biotic constraints such as parasitic weeds. This paper assesses the impact of infestation by parasitic weeds on rice farmers’ technical efficiency and examines the potential role of managerial factors in improving technical efficiency. Household and field survey data were collected from rice farmers in Cote d’Ivoire and Benin in West Africa. A stochastic frontier production function was estimated, which allows for identifying the levels of exogenous factors that prevent farmers from improving technical efficiency levels. The results suggest that farmers cope with parasitic weeds through learning from experiencing infestations by parasitic weed. The results will assist national extension in designing segmented training programmes that are better tailored to rice farmers’ needs and preventing food security from being jeopardized by parasitic weeds

Jet propulsion without inertia

A body immersed in a highly viscous fluid can locomote by drawing in and expelling fluid through pores at its surface. We consider this mechanism of jet propulsion without inertia in the case of spheroidal bodies, and derive both the swimming velocity and the hydrodynamic efficiency. Elementary examples are presented, and exact axisymmetric solutions for spherical, prolate spheroidal, and oblate spheroidal body shapes are provided. In each case, entirely and partially porous (i.e. jetting) surfaces are considered, and the optimal jetting flow profiles at the surface for maximizing the hydrodynamic efficiency are determined computationally. The maximal efficiency which may be achieved by a sphere using such jet propulsion is 12.5%, a significant improvement upon traditional flagella-based means of locomotion at zero Reynolds number. Unlike other swimming mechanisms which rely on the presentation of a small cross section in the direction of motion, the efficiency of a jetting body at low Reynolds number increases as the body becomes more oblate, and limits to approximately 162% in the case of a flat plate swimming along its axis of symmetry. Our results are discussed in the light of slime extrusion mechanisms occurring in many cyanobacteria

Ac conductivity and dielectric properties of CuFe1−xCrxO2 : Mg delafossite

The electrical and dielectric properties of CuFe(1−x)Cr(x)O(2) (0 ≤ x ≤ 1) powders, doped with 3% of Mg and prepared by solid-state reaction, were studied by broadband dielectric spectroscopy in the temperature range from −100 to 150 °C. The frequency-dependent electrical and dielectric data have been discussed in the framework of a power law conductivity and complex impedance and dielectric modulus. At room temperature, the ac conductivity behaviour is characteristic of the charge transport in CuFe1−xCrxO2 powders. The substitution of Fe3+ by Cr3+ results in an increase in dc conductivity and a decrease in the Cu+–Cu+ distance. Dc conductivity, characteristic onset frequency and Havriliak–Negami characteristics relaxation times are thermally activated above −40 °C for x = 0.835. The associated activation energies obtained from dc and ac conductivity and from impedance and modulus losses are similar and show that CuFe1−xCrxO2 delafossite powders satisfy the BNN relation. Dc and ac conductivities have the same transport mechanism, namely thermally activated nearest neighbour hopping and tunnelling hopping above and below −40 °C, respectively

Bergmann and converse bergmann latitudinal clines in arthropods: two ends of a continuum?

Two seemingly opposite evolutionary patterns of clinal variation in body size and associated life history traits exist in nature. According to Bergmann's rule, body size increases with latitude, a temperature effect. According to the converse Bergmann rule, body size decreases with latitude, a season length effect. A third pattern causally related to the latter is countergradient variation, whereby populations of a given species compensate seasonal limitations at higher latitudes by evolving faster growth and larger body sizes compared to their low latitude conspecifics. We discuss these patterns and argue that they are not mutually exclusive because they are driven by different environmental causes and proximate mechanisms; they therefore can act in conjunction, resulting in any intermediate pattern. Alternatively, Bergmann and converse Bergmann clines can be interpreted as over- and undercompensating countergradient variation, respectively. We illustrate this with data for the wide-spread yellow dung fly, Scathophaga stercoraria (Diptera: Scathophagidae), which in Europe shows a Bergmann cline for size and a converse Bergmann cline (i.e., countergradient variation) for development time. A literature review of the available evidence on arthropod latitudinal clines further shows a patterned continuum of responses. Converse Bergmann clines due to end-of-season time limitations are more common in larger species with longer development times. Our study thus provides a synthesis to the controversy about the importance of Bergmann's rule and the converse Bergmann rule in natur

Environmental quality alters female costs and benefits of evolving under enforced monogamy

Background Currently many habitats suffer from quality loss due to environmental change. As a consequence, evolutionary trajectories might shift due to environmental effects and potentially increase extinction risk of resident populations. Nevertheless, environmental variation has rarely been incorporated in studies of sexual selection and sexual conflict, although local environments and individuals’ condition undoubtedly influence costs and benefits. Here, we utilise polyandrous and monogamous selection lines of flour beetles, which evolved in presence or absence of sexual selection for 39 generations. We specifically investigated effects of low vs. standard food quality (i.e. stressful vs. benign environments) on reproductive success of cross pairs between beetles from the contrasting female and male selection histories to assess gender effects driving fitness. Results We found a clear interaction of food quality, male selection history and female selection history. Monogamous females generally performed more poorly than polyandrous counterparts, but reproductive success was shaped by selection history of their mates and environmental quality. When monogamous females were paired with polyandrous males in the standard benign environment, females seemed to incur costs, possibly due to sexual conflict. In contrast, in the novel stressful environment, monogamous females profited from mating with polyandrous males, indicating benefits of sexual selection outweigh costs. Conclusions Our findings suggest that costs and benefits of sexually selected adaptations in both sexes can be profoundly altered by environmental quality. With regard to understanding possible impacts of environmental change, our results further show that the ecology of mating systems and associated selection pressures should be considered in greater detail

Chronic symptoms in a representative sample of community-dwelling older people: a cross-sectional study in Switzerland.

The burden of multiple diagnoses is well documented in older people, but less is known about chronic symptoms, many of which are even not brought to medical attention. This study aimed to determine the prevalence of chronic symptoms, their relationships with disability in basic activities of daily living (BADL) and quality of life (QoL), and their public health impact. A large cross-sectional population-based study. Community in 2 regions of French-speaking Switzerland. Community-dwelling older adults aged 68 years and older in 2011 (N=5300). Disability in BADL defined as difficulty or help needed with any of dressing, bathing, eating, getting in/out of bed or an arm chair, and using the toilet. Overall QoL dichotomised as favourable (ie, excellent or very good) or unfavourable (ie, good, fair or poor). Disturbance by any of the following 14 chronic symptoms for at least 6 months: joint pain, back pain, chest pain, dyspnoea, persistent cough, swollen legs, memory gaps, difficulty concentrating, difficulty making decisions, dizziness/vertigo, skin problems, stomach/intestine problems, urinary incontinence and impaired sexual life. Only 17.1% of participants did not report being disturbed by any of these chronic symptoms. Weighted prevalence ranged from 3.1% (chest pain) to 47.7% (joint pain). Most chronic symptoms were significantly associated with disability in BADL or unfavourable QoL, with substantial gender differences. The number of chronic symptoms was significantly associated with disability in BADL and unfavourable QoL, with gradients suggesting dose-response relationships. Joint pain and back pain had the highest population attributable fractions. Chronic symptoms are highly prevalent in older people, and are associated with disability in BADL and unfavourable QoL, particularly when multiple chronic symptoms co-occur. Owing to their high public health impact, musculoskeletal chronic symptoms represent good targets for preventive interventions