677 research outputs found
An investigation into the genetics of isolated brown trout (Salmo trutta L.) populations. Progress Report
Environmental risk assessment of GE plants under low-exposure conditions
The requirement for environmental risk assessment (ERA) of genetically engineered (GE) plants prior to large scale or commercial introduction into the environment is well established in national laws and regulations, as well as in international agreements. Since the first introductions of GE plants in commercial agriculture in the 1990s, a nearly universal paradigm has emerged for conducting these assessments based on a few guiding principles. These include the concept of case-by-case assessment, the use of comparative assessments, and a focus of the ERA on characteristics of the plant, the introduced trait, and the receiving environment as well as the intended use. In practice, however, ERAs for GE plants have frequently focused on achieving highly detailed characterizations of potential hazards at the expense of consideration of the relevant levels of exposure. This emphasis on exhaustive hazard characterization can lead to great difficulties when applied to ERA for GE plants under low-exposure conditions. This paper presents some relevant considerations for conducting an ERA for a GE plant in a low-exposure scenario in the context of the generalized ERA paradigm, building on discussions and case studies presented during a session at ISBGMO 12
Pb-Zn and minor U mineralization at Tyndrum, Scotland.
This mineralization occurs as veins and vein breccias in fractures associated with the Tyndrum-Glen Fyne fault. Quartz, galena and sphalerite, with minor chalcopyrite and baryte, are accompanied by small inclusions (in the galena-rich veins) of tetrahedrite, pyrargyrite, marcasite and pyrite. Uraniferous veins post-date the main Pb-Zn mineralization and contain uraninite, calcite, baryte, galena, sphalerite, chalcopyrite, argentite, chalcocite, tetrahedrite and safflorite. Fluid inclusion studies indicate a mineralizing solution with approx 20 wt.% equiv. NaCl + KCl, a Na/K ratio of 3:1 and which was boiling during mineral precipitation. The depositional sequence is discussed.-R.A.H
Constant amplitude and post-overload fatigue crack growth behavior in PM aluminum alloy AA 8009
A recently developed, rapidly solidified, powder metallurgy, dispersion strengthened aluminum alloy, AA 8009, was fatigue tested at room temperature in lab air. Constant amplitude/constant delta kappa and single spike overload conditions were examined. High fatigue crack growth rates and low crack closure levels compared to typical ingot metallurgy aluminum alloys were observed. It was proposed that minimal crack roughness, crack path deflection, and limited slip reversibility, resulting from ultra-fine microstructure, were responsible for the relatively poor da/dN-delta kappa performance of AA 8009 as compared to that of typical IM aluminum alloys
Environmental risk assessment of genetically modified plants - concepts and controversies
Background and purpose: In Europe, the EU Directive 2001/18/EC lays out the main provisions of environmental risk assessment (ERA) of genetically modified (GM) organisms that are interpreted very differently by different stakeholders. The purpose of this paper is to: (a) describe the current implementation of ERA of GM plants in the EU and its scientific shortcomings, (b) present an improved ERA concept through the integration of a previously developed selection procedure for identification of non-target testing organisms into the ERA framework as laid out in the EU Directive 2001/18/EC and its supplement material (Commission Decision 2002/623/EC), (c) describe the activities to be carried out in each component of the ERA and (d) propose a hierarchical testing scheme. Lastly, we illustrate the outcomes for three different crop case examples.
Main features: Implementation of the current ERA concept of GM crops in the EU is based on an interpretation of the EU regulations that focuses almost exclusively on the isolated bacteria-produced novel proteins with little consideration of the whole plant. Therefore, testing procedures for the effect assessment of GM plants on non-target organisms largely follow the ecotoxicological testing strategy developed for pesticides. This presumes that any potential adverse effect of the whole GM plant and the plant-produced novel compound can be extrapolated from testing of the isolated bacteriaproduced novel compound or can be detected in agronomic field trials. This has led to persisting scientific criticism.
Results: Based on the EU ERA framework, we present an improved ERA concept that is system oriented with the GM plant at the centre and integrates a procedure for selection of testing organisms that do occur in the receiving environment. We also propose a hierarchical testing scheme from laboratory studies to field trials and we illustrate the outcomes for three different crop case examples.
Conclusions and recommendations: Our proposed concept can alleviate a number of deficits identified in the current approach to ERA of GM plants. It allows the ERA to be tailored to the GM plant case and the receiving environment
Assessment of risk of insect-resistant transgenic crops to nontarget arthropods
An international initiative is developing a scientifically rigorous approach to evaluate the potential risks to nontarget arthropods (NTAs) posed by insect-resistant, genetically modified (IRGM) crops. It adapts the tiered approach to risk assessment that is used internationally within regulatory toxicology and environmental sciences. The approach focuses on the formulation and testing of clearly stated risk hypotheses, making maximum use of available data and using formal decision guidelines to progress between testing stages (or tiers). It is intended to provide guidance to regulatory agencies that are currently developing their own NTA risk assessment guidelines for IRGM crops and to help harmonize regulatory requirements between different countries and different regions of the world
“The future is unstable”: Exploring changing fertility intentions in the United Kingdom during the COVID-19 pandemic
Objective: To understand whether reproductive decision-making among United Kingdom (UK) respondents had changed in light of the COVID-19 pandemic and, if so, why COVID-19 had led them to change their intentions. Methods: We conducted a cross-sectional online survey in January 2021. We asked survey participants if their fertility intentions had changed and to rate how aspects of their life had changed during COVID-19. We also included an open-ended question and asked participants to explain in their own words how COVID-19 had influenced their reproductive decision-making. We used descriptive and regression analyses to explore the quantitative data and thematically analyzed written responses. Results: Nine percent (n = 70) of our 789 UK respondents reported a change in fertility intention after the start of the pandemic. Changes in both pro-natal and anti-natal directions made the overall change in intentions small: there was a 2% increase across the sample in not intending a child between the two time points. Only increased financial insecurity was predictive of changing intentions. Responses to the open-ended question (n = 103) listed health concerns, indirect costs of the pandemic, and changing work-life priorities as reasons for changing their intentions. Conclusion: While studies conducted at the beginning of the pandemic found that fertility intentions became more anti-natal, we found little overall change in fertility intentions in January 2021. Our findings of small pro-natal and anti-natal changes in fertility intentions align with emerging UK birth rate data for 2021, which show minimal change in the total fertility rate in response to the pandemic
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