1,212 research outputs found
Acidification in Europe : A Simulation Model for Evaluating Control Strategies
RAINS (Regional Acidification Information and Simulation) is an integrated model of acidification in Europe designed as a tool for evaluating control strategies. It is currently sulfur-based, but is being expanded to include nitrogen species. Emphasis of the model is on the transboundary aspects of the acidification problem. Model computations are performed on a personal computer. Linked submodels are available for SO2 emissions, cost of control strategies, atmospheric transport of sulfur, forest soil and groundwater acidity, lake acidification, and the direct impact of SO2 on forests. The model can be used for scenario analysis, where the user prescribes a control strategy and then examines the cost and environmental consequences of this strategy, or for optimization analysis, in which the user sets cost and deposition goals, and identifies an "optimal" sulfur-reduction strategy. Preliminary use of the model has pointed to 1. the importance of examining long-term environmental consequences of control strategies, and 2. the cost advantages of a cooperative European sulfur-reduction program
The effects of CO2, climate and land-use on terrestrial carbon balance, 1920-1992: An analysis with four process-based ecosystem models
The concurrent effects of increasing atmospheric CO2 concentration, climate variability, and cropland establishment and abandonment on terrestrial carbon storage between 1920 and 1992 were assessed using a standard simulation protocol with four process-based terrestrial biosphere models. Over the long-term(1920–1992), the simulations yielded a time history of terrestrial uptake that is consistent (within the uncertainty) with a long-term analysis based on ice core and atmospheric CO2 data. Up to 1958, three of four analyses indicated a net release of carbon from terrestrial ecosystems to the atmosphere caused by cropland establishment. After 1958, all analyses indicate a net uptake of carbon by terrestrial ecosystems, primarily because of the physiological effects of rapidly rising atmospheric CO2. During the 1980s the simulations indicate that terrestrial ecosystems stored between 0.3 and 1.5 Pg C yr−1, which is within the uncertainty of analysis based on CO2 and O2 budgets. Three of the four models indicated (in accordance with O2 evidence) that the tropics were approximately neutral while a net sink existed in ecosystems north of the tropics. Although all of the models agree that the long-term effect of climate on carbon storage has been small relative to the effects of increasing atmospheric CO2 and land use, the models disagree as to whether climate variability and change in the twentieth century has promoted carbon storage or release. Simulated interannual variability from 1958 generally reproduced the El Niño/Southern Oscillation (ENSO)-scale variability in the atmospheric CO2 increase, but there were substantial differences in the magnitude of interannual variability simulated by the models. The analysis of the ability of the models to simulate the changing amplitude of the seasonal cycle of atmospheric CO2 suggested that the observed trend may be a consequence of CO2 effects, climate variability, land use changes, or a combination of these effects. The next steps for improving the process-based simulation of historical terrestrial carbon include (1) the transfer of insight gained from stand-level process studies to improve the sensitivity of simulated carbon storage responses to changes in CO2 and climate, (2) improvements in the data sets used to drive the models so that they incorporate the timing, extent, and types of major disturbances, (3) the enhancement of the models so that they consider major crop types and management schemes, (4) development of data sets that identify the spatial extent of major crop types and management schemes through time, and (5) the consideration of the effects of anthropogenic nitrogen deposition. The evaluation of the performance of the models in the context of a more complete consideration of the factors influencing historical terrestrial carbon dynamics is important for reducing uncertainties in representing the role of terrestrial ecosystems in future projections of the Earth system
The Barents area changes – How will Finland adapt? (Barentsin alue muuttuu – miten Suomi sopeutuu?)
The cumulative impacts of environmental, climatic and societal changes and their consequences will affect the development of the Arctic region in the coming decades. Adaptation to these changes will require measures of all the actors in the region. Finland, part of the Euro-Arctic region, will adapt to these changes in a variety of ways. The Barents area is unique in the Arctic in being a multicultural, relatively densely populated area with well-developed industries and infrastructure.
This report examines adaptation to changes and their consequences in the Barents area in terms of governance and Finland’s capacities to adapt. The aim has been to produce comprehensive information from the Finnish perspective for local and national decision-makers about long-term changes in the region, their expected impacts and adaptation options, and to support decision-making that will advance adaptation. The report includes recommendations.
This report is based on the contribution of Finnish experts to an Arctic Council and Arctic Monitoring and Assessment Programme (AMAP) project titled ”Adaptation Actions for a Changing Arctic” (AACA). The project has prepared a pilot report by Nordic and Russian experts on the Barents area in English on changes, their impacts and adaptation options. The report will be published in 2017 (AMAP 2017)
Seasonal population dynamics of the invasive polychaete genus Marenzelleria spp. in contrasting soft-sediment habitats
Three species of the invasive polychaete genus Marenzelleria are among the dominant benthic taxa in many, especially deeper, areas in the Baltic Sea. The population dynamics of the polychaetes in the Baltic are, however, still largely unknown. We conducted monthly samplings of the benthic communities and environmental parameters at five sites with differing depths and sediment characteristics in the northern Baltic Sea (59 degrees 50.896', 23 degrees 15.092') to study the population dynamics, productivity and growth of Marenzelleria spp. from April 2013 to June 2014. The species of Marenzelleria occurring at the study sites were identified by genetic analyses. At the deepest site (33 m) only M. arctia was present, while all three species were found at the shallower, muddy sites (up to 20 m depth). At the shallow (6 m) sandy site only M. viridis and M. neglecta occurred. The sites differed in the seasonal dynamics of the Marenzelleria spp. population, reflecting the different species identities. The muddy sites up to 20 m depth showed clear seasonal dynamics, with the population practically disappearing by winter, whereas more stable populations occurred at the deepest site and at the sandy site. The highest density, biomass and production were observed at the 20 m deep, organic-rich muddy site where all three species recruited. The seasonally very high densities are likely to have important consequences for organic matter processing, and species interactions at these sites. The observed high productivity of the populations has possibly facilitated their establishment, and considerably increased secondary production in especially the deeper areas.Peer reviewe
Multiscale segmentation of exudates in retinal images using contextual cues and ensemble classification
Genome-wide analyses for personality traits identify six genomic loci and show correlations with psychiatric disorders
Personality is influenced by genetic and environmental factors1
and associated with mental health. However, the underlying
genetic determinants are largely unknown. We identified six
genetic loci, including five novel loci2,3, significantly associated
with personality traits in a meta-analysis of genome-wide
association studies (N = 123,132–260,861). Of these genomewide
significant loci, extraversion was associated with variants
in WSCD2 and near PCDH15, and neuroticism with variants
on chromosome 8p23.1 and in L3MBTL2. We performed a
principal component analysis to extract major dimensions
underlying genetic variations among five personality traits
and six psychiatric disorders (N = 5,422–18,759). The first
genetic dimension separated personality traits and psychiatric
disorders, except that neuroticism and openness to experience
were clustered with the disorders. High genetic correlations
were found between extraversion and attention-deficit–
hyperactivity disorder (ADHD) and between openness and
schizophrenia and bipolar disorder. The second genetic
dimension was closely aligned with extraversion–introversion
and grouped neuroticism with internalizing psychopathology
(e.g., depression or anxiety)
Defects in Meiotic Recombination Delay Progression Through Pachytene in Tex19.1-/- Mouse Spermatocytes
Recombination, synapsis, chromosome segregation and gene expression are co-ordinately regulated during meiosis to ensure successful execution of this specialised cell division. Studies with multiple mutant mouse lines have shown that mouse spermatocytes possess quality control checkpoints that eliminate cells with persistent defects in chromosome synapsis. In addition, studies on Trip13 mod/mod mice suggest that pachytene spermatocytes that successfully complete chromosome synapsis can undergo meiotic arrest in response to defects in recombination. Here, we present additional support for a meiotic recombination-dependent checkpoint using a different mutant mouse line, Tex19.1 −/− . The appearance of early recombination foci is delayed in Tex19.1 −/− spermatocytes during leptotene/zygotene, but some Tex19.1 −/− spermatocytes still successfully synapse their chromosomes and we show that these spermatocytes are enriched for early recombination foci. Furthermore, we show that patterns of axis elongation, chromatin modifications and histone H1t expression are also all co-ordinately skewed towards earlier substages of pachytene in these autosomally synapsed Tex19.1 −/− spermatocytes. We also show that this skew towards earlier pachytene substages occurs in the absence of elevated spermatocyte death in the population, that spermatocytes with features of early pachytene are present in late stage Tex19.1 −/− testis tubules and that the delay in histone H1t expression in response to loss of Tex19.1 does not occur in a Spo11 mutant background. Taken together, these data suggest that a recombination-dependent checkpoint may be able to modulate pachytene progression in mouse spermatocytes to accommodate some types of recombination defect
An algorithm for network-based gene prioritization that encodes knowledge both in nodes and in links
Background: Candidate gene prioritization aims to identify promising new genes associated with a disease or a biological process from a larger set of candidate genes. In recent years, network-based methods - which utilize a knowledge network derived from biological knowledge - have been utilized for gene prioritization. Biological knowledge can be encoded either through the network's links or nodes. Current network-based methods can only encode knowledge through links. This paper describes a new network-based method that can encode knowledge in links as well as in nodes. Results: We developed a new network inference algorithm called the Knowledge Network Gene Prioritization (KNGP) algorithm which can incorporate both link and node knowledge. The performance of the KNGP algorithm was evaluated on both synthetic networks and on networks incorporating biological knowledge. The results showed that the combination of link knowledge and node knowledge provided a significant benefit across 19 experimental diseases over using link knowledge alone or node knowledge alone. Conclusions: The KNGP algorithm provides an advance over current network-based algorithms, because the algorithm can encode both link and node knowledge. We hope the algorithm will aid researchers with gene prioritization. © 2013 Kimmel, Visweswaran
Tex19.1 Promotes Spo11-Dependent Meiotic Recombination in Mouse Spermatocytes
Meiosis relies on the SPO11 endonuclease to generate the recombinogenic DNA double strand breaks (DSBs) required for homologous chromosome synapsis and segregation. The number of meiotic DSBs needs to be sufficient to allow chromosomes to search for and find their homologs, but not excessive to the point of causing genome instability. Here we report that the mammal-specific gene Tex19.1 promotes Spo11-dependent recombination in mouse spermatocytes. We show that the chromosome asynapsis previously reported in Tex19.1-/- spermatocytes is preceded by reduced numbers of recombination foci in leptotene and zygotene. Tex19.1 is required for normal levels of early Spo11-dependent recombination foci during leptotene, but not for upstream events such as MEI4 foci formation or accumulation of H3K4me3 at recombination hotspots. Furthermore, we show that mice carrying mutations in Ubr2, which encodes an E3 ubiquitin ligase that interacts with TEX19.1, phenocopy the Tex19.1-/- recombination defects. These data suggest that Tex19.1 and Ubr2 are required for mouse spermatocytes to accumulate sufficient Spo11-dependent recombination to ensure that the homology search is consistently successful, and reveal a hitherto unknown genetic pathway promoting meiotic recombination in mammals
Monetäre Bewertung der wirtschaftlichen Folgen neuartiger Waldschäden anhand internationaler Daten
Vortrag im Symposium über Bewertung von Waldschäden infolge von Luftverunreinigungen. Gmunden, Österreich 13. -17. September 1988. IUFRO Arbeitsgruppe S4.04. -02
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