239 research outputs found

    Road and railway verges serve as dispersal corridors for grassland plants

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    The role of linear habitat strips as dispersal corridors is a disputed topic. Reports concerning their significance for animals have been contradictory, and the functions of corridors have been difficult to study in the case of sedentary organisms such as plants. Previous studies on dispersal of plants along corridors have concentrated on a single or a few species at a time. We developed a general method, a generalisation of the binomial test, for considering dispersal or spatial relations of a large group of species. Particularly, we studied the ability of grassland plants to spread along road and railway verges. Our data set consists of plant lists collected at study plots scattered irregularly along road and railway networks. The dispersal ability was assessed by testing whether the species composition at neighbouring sites – measured along roads and railways – reflects spatial dependence within each species. Our result showed that similar combinations of grassland species occurred at neighbouring sites more often than expected in a spatially independent case. We argue that management of verges and spatial autocorrelation of environmental factors were not responsible for the result and thereby we conclude that grassland plants use road and railway corridors for dispersal. This result is encouraging in regards to preservation of grassland plant populations. Although semi-natural and natural grasslands have become scarce, road and railway embankments may partly compensate for this loss, serving as substitute habitats and dispersal routes

    Conservation contracts in habitat protection in southern Finland

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    Demands for additional conservation of forests have been strong in Finland where a remarkable number of threatened species need wooded lands. In the southern half of the country the proportion of strictly protected forestland is as low as 1.1% and three quarters of forests are owned by private individuals and families. In order to promote forest protection on private lands the possibilities of landowners to participate in decision making should be improved. To assess the role of voluntary or incentive-based conservation contracts in protection of privately owned forestlands two existing conservation practices were studied: (1) voluntary establishment of permanent nature reserves and (2) payment of environmental grants that are appropriated for fixed-periods and that compensate for statutory preservation of woodland key habitats. Mean areas and compensation sums associated with sites protected using these two practices were simply compared to each other. Nature reserves were on average larger than key habitat sites. However, in the long run fixed-period environmental grants paid for key habitats provide landowners with higher compensation than that paid for establishing permanent nature reserves. These results are assessed in the light of international discussion on social, economic and ecological factors related to protection of private lands. © 2003 Elsevier Science Ltd. All rights reserved

    Conservation implications of exporting domestic wood harvest to neighboring countries

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    Among wealthy countries, increasing imports of natural resources to allow for unchecked consumption and greater domestic environmental conservation has become commonplace. This practice can negatively affect biodiversity conservation planning if natural resource harvest is merely pushed across political borders. As an example, we focus on the boreal forest ecosystem of Finland and northwest Russia. While the majority of protected forests are in northern Finland, the majority of biodiversity is in southern Finland, where protection is more difficult due to high private ownership, and the effectiveness of functioning conservation networks is more uncertain due to a longer history of land use. In northwest Russia, the current protected areas are inadequate to preserve most of the region’s naturally dynamic and old growth forests. Increased importation of wood from northwest Russia to Finland may jeopardize the long-term viability of species in high diversity conservation areas in both Russia and Finland, through isolating conservation areas and lowering the age of the surrounding forest mosaic. The boreal forest ecosystem of Fennoscandia and northwest Russia would thus be best conserved by a large scale, coordinated conservation strategy that addresses long-term conservation goals and wood consumption, forest industries, logging practices and trade

    Importing Timber, Exporting Ecological Impact

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    Covering 32% of the planet, boreal forests are one of the last relatively intact terrestrial biomes, and are a critical carbon sink in global climate dynamics. Mature and old-growth boreal forests provide a large number of products that are culturally and economically important, from wood-based lumber, pulp, and fuel wood, to numerous nonwood products. Intensive wood harvest and conservation of naturally dynamic intact forests tend to be mutually exclusive; where biodiversity is highly valued, wood harvests are limited or banned outright. The authors of this Policy Forum advise that increasing domestic forest protection without decreasing demand for wood necessitates an increase in foreign imports, which introduces a negative impact on forest biodiversity elsewhere. In some cases, exporting impact across the border may cause negative impacts to boomerang back into the country's protected forests

    Runs of homozygosity do not influence survival to old age

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    Runs of homozygosity (ROH) are extended tracts of adjacent homozygous single nucleotide polymorphisms (SNPs) that are more common in unrelated individuals than previously thought. It has been proposed that estimating ROH on a genome-wide level, by making use of the genome-wide single nucleotide polymorphism (SNP) data, will enable to indentify recessive variants underlying complex traits. Here, we examined ROH larger than 1.5 Mb individually and in combination for association with survival in 5974 participants of the Rotterdam Study. In addition, we assessed the role of overall homozygosity, expressed as a percentage of the autosomal genome that is in ROH longer than 1.5 Mb, on survival during a mean follow-up period of 12 years. None of these measures of homozygosity was associated with survival to old age

    Patterns of urgent hoarseness referrals to ENT – When should we be suspicious of cancer?

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    Background: Current UK referral criteria stipulate that hoarseness should be persistent to merit 2 week wait (2WW) or urgent suspicion of cancer (USOC) referral. This study delineates patterns of hoarseness presentation with a view to assisting referral pathways, and whereby reassurance could be provided. Methods: A pre-existing database of patients referred with hoarseness under the urgent suspicion of cancer (USOC) category was analysed. Univariate and multivariate analyses were performed on a variety of demographic and comorbid features to produce odds ratios (OR) of features either related or not related to laryngeal cancer. Results: Of 698 consecutive hoarseness referrals were studied. In these referrals there were 506(73%) with persistent hoarseness and 192(27%) with intermittent hoarseness. The most significant patient variables related to laryngeal cancer were persistent hoarseness (OR 4.97), recreational drug use (OR 4.94), male gender (OR 4.01) and weight loss (OR 3.75). Significant patient variables present not related to laryngeal cancer diagnosis were intermittent hoarseness (OR 0.2), the presence of cough (OR 0.2), globus sensation (OR 0.25) and recent viral infection (OR 0.29). Conclusion: The strongest association with cancer is seen in patients that are persistently hoarse. Patients with fluctuating hoarseness do not need an “urgent suspicion of cancer” referral. Additional demographic referral information could help to streamline the referral of these patients, and reassure others

    Minocycline inhibits glial proliferation in the H-Tx rat model of congenital hydrocephalus

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    <p>Abstract</p> <p>Background</p> <p>Reactive astrocytosis and microgliosis are important features of the pathophysiology of hydrocephalus, and persistent glial "scars" that form could exacerbate neuroinflammation, impair cerebral perfusion, impede neuronal regeneration, and alter biomechanical properties. The purpose of this study was to determine the efficacy of minocycline, an antibiotic known for its anti-inflammatory properties, to reduce gliosis in the H-Tx rat model of congenital hydrocephalus.</p> <p>Methods</p> <p>Minocycline (45 mg/kg/day i.p. in 5% sucrose at a concentration of 5-10 mg/ml) was administered to hydrocephalic H-Tx rats from postnatal day 15 to day 21, when ventriculomegaly had reached moderate to severe stages. Treated animals were compared to age-matched non-hydrocephalic and untreated hydrocephalic littermates. The cerebral cortex (both gray matter laminae and white matter) was processed for immunohistochemistry (glial fibrillary acidic protein, GFAP, for astrocytes and ionized calcium binding adaptor molecule, Iba-1, for microglia) and analyzed by qualitative and quantitative light microscopy.</p> <p>Results</p> <p>The mean number of GFAP-immunoreactive astrocytes was significantly higher in untreated hydrocephalic animals compared to both types of controls (<it>p </it>< 0.001). Minocycline treatment of hydrocephalic animals reduced the number of GFAP immunoreactive cells significantly (<it>p </it>< 0.001). Likewise, the mean number of Iba-1 immunoreactive microglia was significantly higher in untreated hydrocephalic animals compared to both types of controls (<it>p </it>< 0.001). Furthermore, no differences in the numbers of GFAP-positive astrocytes or Iba-1-positive microglia were noted between control animals receiving no minocycline and control animals receiving minocycline, suggesting that minocycline does not produce an effect under non-injury conditions. Additionally, in six out of nine regions sampled, hydrocephalic animals that received minocycline injections had significantly thicker cortices when compared to their untreated hydrocephalic littermates.</p> <p>Conclusions</p> <p>Overall, these data suggest that minocycline treatment is effective in reducing the gliosis that accompanies hydrocephalus, and thus may provide an added benefit when used as a supplement to ventricular shunting.</p

    Stimulus-Related Independent Component and Voxel-Wise Analysis of Human Brain Activity during Free Viewing of a Feature Film

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    Understanding how the brain processes stimuli in a rich natural environment is a fundamental goal of neuroscience. Here, we showed a feature film to 10 healthy volunteers during functional magnetic resonance imaging (fMRI) of hemodynamic brain activity. We then annotated auditory and visual features of the motion picture to inform analysis of the hemodynamic data. The annotations were fitted to both voxel-wise data and brain network time courses extracted by independent component analysis (ICA). Auditory annotations correlated with two independent components (IC) disclosing two functional networks, one responding to variety of auditory stimulation and another responding preferentially to speech but parts of the network also responding to non-verbal communication. Visual feature annotations correlated with four ICs delineating visual areas according to their sensitivity to different visual stimulus features. In comparison, a separate voxel-wise general linear model based analysis disclosed brain areas preferentially responding to sound energy, speech, music, visual contrast edges, body motion and hand motion which largely overlapped the results revealed by ICA. Differences between the results of IC- and voxel-based analyses demonstrate that thorough analysis of voxel time courses is important for understanding the activity of specific sub-areas of the functional networks, while ICA is a valuable tool for revealing novel information about functional connectivity which need not be explained by the predefined model. Our results encourage the use of naturalistic stimuli and tasks in cognitive neuroimaging to study how the brain processes stimuli in rich natural environments
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