325 research outputs found
Understanding the evolution of native pinewoods in Scotland will benefit their future management and conservation
Scots pine (Pinus sylvestris L.) is a foundation species in Scottish highland forests and a national icon. Due to heavy exploitation, the current native pinewood coverage represents a small fraction of the postglacial maximum. To reverse this decline, various schemes have been initiated to promote planting of new and expansion of old pinewoods. This includes the designation of seed zones for control of the remaining genetic resources. The zoning was based mainly on biochemical similarity among pinewoods but, by definition, neutral molecular markers do not reflect local phenotypic adaptation. Environmental variation within Scotland is substantial and it is not yet clear to what extent this has shaped patterns of adaptive differentiation among Scottish populations. Systematic, rangewide common-environment trials can provide insights into the evolution of the native pinewoods, indicating how environment has influenced phenotypic variation and how variation is maintained. Careful design of such experiments can also provide data on the history and connectivity among populations, by molecular marker analysis. Together, phenotypic and molecular datasets from such trials can provide a robust basis for refining seed transfer guidelines for Scots pine in Scotland and should form the scientific basis for conservation action on this nationally important habitat
Genetic considerations in ecosystem restoration using native tree species. State of the World’s Forest Genetic Resources – Thematic Study.
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
Evolutionary targets of gene expression divergence in a complex of closely related pine species
The environment is a powerful selective pressure for sessile organisms, such as plants, and adaptation to the environment is particularly important for long-lived species, like trees. Despite the importance of adaptive trait variation to the survival and success of trees, the molecular basis of adaptation is still poorly understood. Gene expression patterns in three closely related, but phenotypically and ecologically divergent, pine species were analyzed to detect differentiation that may be associated with their adaptation to distinct environments. Total RNA of Pinus mugo, Pinus uncinata, and Pinus sylvestris samples grown under common garden conditions was used for de novo transcriptome assembly, providing a new reference dataset that includes species from the taxonomically challenging P. mugo complex. Gene expression profiles were found to be very similar with only 121 genes significantly diverged in any of the pairwise species comparisons. Functional annotation of these genes revealed major categories of distinctly expressed transcripts, including wood trait properties, oxidative stress response, and response to abiotic factors such as salinity, drought, and temperature. We discuss putative associations between gene expression profiles and adaptation to different environments, for example, the upregulation of genes involved in lignin biosynthesis in the species, which have adapted to mountainous regions characterized by strong winds and thick snow cover. Our study provides valid candidates for verification of the importance of the gene expression role, in addition to evidence for selection within genomic regions, in the process of ecological divergence and adaptation to higher altitudes in pine taxa
'This isn't what mine looked like': a qualitative study of symptom appraisal and help seeking in people recently diagnosed with melanoma.
OBJECTIVE: To explore symptom appraisal and help-seeking decisions among patients recently diagnosed with melanomas, and to compare experiences of people with 'thinner' (2 mm) melanomas, as thickness at diagnosis is an important prognostic feature. METHODS: In-depth interviews with patients within 10 weeks of melanoma diagnosis explored the factors impacting on their pathways to diagnosis. Framework analysis, underpinned by the Model of Pathways to Treatment, was used to explore the data with particular focus on patients' beliefs and experiences, disease factors, and healthcare professional (HCP) influences. RESULTS: 63 patients were interviewed (29-93 years, 31 women, 30 thicker melanomas). All described their skin changes using rich lay vocabulary. Many included unassuming features such as 'just a little spot' as well as common features of changes in size, colour and shape. There appeared to be subtly different patterns of symptoms: descriptions of vertical growth, bleeding, oozing and itch were features of thicker melanomas irrespective of pathological type. Appraisal was influenced by explanations such as normal life changes, prior beliefs and whether skin changes matched known melanoma descriptions. Most decisions to seek help were triggered by common factors such as advice from family and friends. 11 patients reported previous reassurance about their skin changes by a HCP, with little guidance on monitoring change or when it would be appropriate to re-consult. CONCLUSIONS: Patients diagnosed with both thinner and thicker melanomas often did not initially recognise or interpret their skin changes as warning signs or prompts to seek timely medical attention. The findings provide guidance for melanoma awareness campaigns on more appropriate images, helpful descriptive language and the need to stress the often apparently innocuous nature of potentially serious skin changes. The importance of appropriate advice, monitoring and safety-netting procedures by HCPs for people presenting with skin changes is also highlighted.Thanks to our funding organisation the National Awareness and Early Diagnosis Initiative (NAEDI), and to their funding partners: Cancer Research UK; Department of Health, England; Economic and Social Research Council; Health and Social Care Research and Development Division; Public Health Agency, Northern Ireland, National Institute for Social Care and Health Research, Wales and the Scottish Government. All researchers were independent of the funding body and the study sponsors and funder had no role in study design; data collection, analysis and interpretation of data; in the writing of the report; or decision to submit the article for publication.
FW was supported by an NIHR Clinical Lectureship followed by a NIHR Clinician Scientist award at the time of this study. The views expressed in this publication are those of the author(s) and not necessarily those of the NHS, the National Institute for Health Research or the Department of Health.This is the final published version. It's also available from BMJ Open at http://bmjopen.bmj.com/content/4/7/e005566.abstract
Effective management of ecological resilience – are we there yet?
1. Ecological resilience is developing into a credible paradigm for policy development and environmental management for preserving natural capital in a rapidly changing world. However, resilience emerges from complex interactions, limiting the translation of theory into practice.
2. Main limitations include the following: (i) difficulty in quantification and detection of changes in ecological resilience, (ii) a lack of empirical evidence to support preventative or proactive management and (iii) difficulties in managing processes operating across socio-ecological systems that vary in space and time.
3. We highlight recent research with the potential to address these limitations including new and/or improved indicators of resilience and tools to assess scale as a driver of resilience.
4. Synthesis and applications. Effective resilience-based management must be adaptive in nature. To support this, we propose an operational model using resilience-based iterative management actions operating across scales
Decision-Directed Channel Estimation Implementation for Spectral Efficiency Improvement in Mobile MIMO-OFDM
Channel estimation algorithms and their implementations
for mobile receivers are considered in this paper.
The 3GPP long term evolution (LTE) based pilot structure
is used as a benchmark in a multiple-input multiple-output
(MIMO) orthogonal frequency division multiplexing
(OFDM) receiver. The decision directed (DD) space alternating
generalized expectation-maximization (SAGE)
algorithm is used to improve the performance from that of
the pilot symbol based least-squares (LS) channel estimator.
The performance is improved with high user velocities,
where the pilot symbol density is not sufficient. Minimum
mean square error (MMSE) filtering is also used
in estimating the channel in between pilot symbols. The
pilot overhead can be reduced to a third of the LTE pilot overhead with DD channel estimation, obtaining a ten percent
increase in data throughput. Complexity reduction and
latency issues are considered in the architecture design.
The pilot based LS, MMSE and the SAGE channel estimators
are implemented with a high level synthesis tool,
synthesized with the UMC 0.18 μm CMOS technology
and the performance-complexity trade-offs are studied. The
MMSE estimator improves the performance from the simple
LS estimator with LTE pilot structure and has low power
consumption. The SAGE estimator has high power consumption
but can be used with reduced pilot density to
increase the data rate.National Science FoundationTekesElektrobitRenesas Mobile EuropeAcademy of FinlandNokia Siemens NetworksXilin
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Environmental factors and host genetic variation shape the fungal endophyte communities within needles of Scots pine (Pinus sylvestris)
To determine the role of environmental and host genetic factors in shaping fungal endophyte communities we used culturing and metabarcoding techniques to quantify fungal taxa within healthy Scots pine (Pinus sylvestris) needles in a 7-y old provenance-progeny trial replicated at three sites. Both methods revealed a community of ascomycete and basidiomycete taxa dominated by the needle pathogen Lophodermium seditiosum. Differences in fungal endophyte taxon composition and diversity indices were highly significant among trial sites. Within two sites, fungal endophyte communities varied significantly among provenances. Furthermore, the communities differed significantly among maternal families within provenances in 11/15 and 7/15 comparisons involving culture and metabarcoding data respectively. We conclude that both environmental and host genetic variation shape the fungal endophyte community of P. sylvestris needles
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