345 research outputs found

    Using case studies for enhancing capacity in managing forest genetic resources

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    Forest trees are long-lived species with high genetic diversity that is crucial for their survival, regeneration and adaptation. However, forest managers and conservationists are often not well informed about the relevance of genetic aspects to population viability. Lack of understanding of forest genetic resources (FGR) therefore constrains conservation of tree species, increases genetic risks in subsequent generations and hinders adaptation to climate change. Examination of tertiary forestry education curricula shows poor or no coverage of FGR issues, while biology teaching is often devoid of the social and practical realities. A vicious cycle is looming in which teaching and understanding of FGR and its importance to conserving and using forest tree species in protected areas and in production landscapes becomes increasingly marginalised. We describe a case study based approach to teaching and learning about FGR use and conservation, based on real research results and subsequent recommendations. Designed to promote ‘FGR-friendly’ decision-making, the Training Guide covers practical issues in forest and tree conservation and management of both global and local relevance. Each case study provides genetic, ecological and socioeconomic information as a basis for students’ analysis. Teacher’s notes, PowerPoint presentations and videos give background information to each case. The guide is intended for both tertiary education and on-the-job training. The material has proved popular with trainees and is flexible and easy to use in a range of formal and informal learning situations. Case study based modules are currently available in English, Spanish, French, with Russian and Chinese in preparatio

    Genetic considerations in ecosystem restoration using native tree species. State of the World’s Forest Genetic Resources – Thematic Study.

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    There is renewed interest in the use of native tree species in ecosystem restoration for their biodiversity benefits. Growing native tree species in production systems (e.g. plantation forests and subsistence agriculture) can also ensure landscape functionality and support for human livelihoods. Achieving these full benefits requires consideration of genetic aspects that are often neglected, such as suitability of germplasm to the site, quality and quantity of the genetic pool used and regeneration potential. Understanding the extent and nature of gene flow across fragmented agro-ecosystems is also crucial to successful ecosystem restoration. We review the role of genetic considerations in a wide range of ecosystem restoration activities involving trees and evaluate how different approaches take, or could take, genetic aspects into account, leading towards the identification and selection of the most appropriate methods

    Destabilization of dark states and optical spectroscopy in Zeeman-degenerate atomic systems

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    We present a general discussion of the techniques of destabilizing dark states in laser-driven atoms with either a magnetic field or modulated laser polarization. We show that the photon scattering rate is maximized at a particular evolution rate of the dark state. We also find that the atomic resonance curve is significantly broadened when the evolution rate is far from this optimum value. These results are illustrated with detailed examples of destabilizing dark states in some commonly-trapped ions and supported by insights derived from numerical calculations and simple theoretical models.Comment: 14 pages, 10 figure

    Measurement of the 1s-2s energy interval in muonium

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    The 1s-2s interval has been measured in the muonium ({μ+e\mu^+e^-}) atom by Doppler-free two-photon laser spectroscopy. The frequency separation of the states was determined to be 2 455 528 941.0(9.8)~MHz in good agreement with quantum electrodynamics. The muon-electron mass ratio can be extracted and is found to be 206.768 38(17). The result may be interpreted as measurement of the muon-electron charge ratio as 11.1(2.1)109-1- 1.1(2.1)\cdot 10^{-9}

    North Sea mackerel egg survey: dutch participation may and June 2011

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    Every three years an international North Sea survey is carried out by two European institutes, Institute for Marine Research (IMR) from Norway and Institute for Marine Resources and Ecosystem Studies (IMARES) from the Netherlands, to monitor the spatial and seasonal distribution of North Sea mackerel. In 2011 the North Sea mackerel egg survey was performed. The entire spawning area was sampled by IMR, Norway and IMARES, The Netherlands. The whole spawning area was sampled three times. IMARES covered the complete sampling area in the first period, in the second period IMR covered the northern part and IMARES the southern part of the spawning area. The third period the whole spawning area was covered by IMR. In total 190 ichthyoplankton samples were taken with a Gulf VII plankton torpedo with a Seabird CTD mounted on top. Additionally, adult fish samples for the estimation of fecundity and atresia were taken using a pelagic trawl. The survey was successful and IMARES managed to sample all but 3 of the planned stations. Numbers of mackerel eggs found in the samples were comparable to 2008. Total mackerel egg production in 2011 was 116*1012 and Spawning Stock Biomass (SSB) was estimated at 165*103 tons, which is slightly higher compared to 2008. Highest egg production was found in the first sampling week and it is possible that the beginning of mackerel spawning is missed

    Expiratory flow rate, breath hold and anatomic dead space influence electronic nose ability to detect lung cancer

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    BACKGROUND: Electronic noses are composites of nanosensor arrays. Numerous studies showed their potential to detect lung cancer from breath samples by analysing exhaled volatile compound pattern ("breathprint"). Expiratory flow rate, breath hold and inclusion of anatomic dead space may influence the exhaled levels of some volatile compounds; however it has not been fully addressed how these factors affect electronic nose data. Therefore, the aim of the study was to investigate these effects. METHODS: 37 healthy subjects (44 +/- 14 years) and 27 patients with lung cancer (60 +/- 10 years) participated in the study. After deep inhalation through a volatile organic compound filter, subjects exhaled at two different flow rates (50 ml/sec and 75 ml/sec) into Teflon-coated bags. The effect of breath hold was analysed after 10 seconds of deep inhalation. We also studied the effect of anatomic dead space by excluding this fraction and comparing alveolar air to mixed (alveolar + anatomic dead space) air samples. Exhaled air samples were processed with Cyranose 320 electronic nose. RESULTS: Expiratory flow rate, breath hold and the inclusion of anatomic dead space significantly altered "breathprints" in healthy individuals (p 0.05). These factors also influenced the discrimination ability of the electronic nose to detect lung cancer significantly. CONCLUSIONS: We have shown that expiratory flow, breath hold and dead space influence exhaled volatile compound pattern assessed with electronic nose. These findings suggest critical methodological recommendations to standardise sample collections for electronic nose measurements
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