504 research outputs found

    Atmospheric nitrogen deposition in terrestrial ecosystems:Its impact on plant communities and consequences across trophic levels

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    The global nitrogen cycle has been greatly perturbed by human activities resulting in elevated nitrogen deposition in many parts of the world. The threat nitrogen deposition poses to ecosystem function and biodiversity is increasingly recognised. In terrestrial systems, impacts on the plant community are mainly through eutrophication and soil acidification. Interactions with secondary environmental drivers such as extreme weather and disease are also key mechanisms. Impacts on consumers can be caused by changes in the quality or quantity of food as a result of changes in food plant chemistry or species composition, changes in vegetation structure leading to a change in the availability of prey species, nesting sites or cooled microclimates or changes in the phenology of plants leading to causing phenological asynchrony. Primary consumers have received considerably less research attention than plants but negative impacts have been observed for both folivorous insects and pollinators. Mammal herbivores have received little research attention. New analysis of changes in plant traits along a gradient of nitrogen deposition in the UK shows that plants pollinated by large bees were negatively associated with N deposition whilst low pH was associated with lower nectar production, reduced occurrence of plants pollinated by long-tongued insects and a reduction in plants with larger floral units. Very few studies have investigated the effects on secondary consumers, but those that have suggest that there are likely to be negative impacts. This review identifies considerable knowledge gaps in the impacts of N deposition on higher tropic levels and highlights that for many groups, knowledge of N deposition impacts is patchy at best. Evidence that has been collected suggests that there are likely to be impacts on primary and secondary consumers making this a priority area for investigation

    PR-software: Stikstof-Bemestingsadvies

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    Het nieuwe, verfijnde stikstofbemestingsadvies voor grasland is door het PR vertaald in het computerprogramma N-advies. Met dit programma kan direct het stikstofbemestingsadvies voor een afzonderlijke snede vastgesteld worden. Het nieuwe advies kan ook in bestaande managementpakketten voor graslandbeheer opgenomen worden

    Evolving information systems: meeting the ever-changing environment

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    To meet the demands of organizations and their ever-changing environment, information systems are required which are able to evolve to the same extent as organizations do. Such a system has to support changes in all time-and application-dependent aspects. In this paper, requirements and a conceptual framework for evolving information systems are presented. This framework includes an architecture for such systems and a revision of the traditional notion of update. Based on this evolutionary notion of update (recording, correction and forgetting) a state transition-oriented model on three levels of abstraction (event level, recording level, correction level) is introduced. Examples are provided to illustrate the conceptual framework for evolving information systems

    Herstelmaatregelen in heideterreinen; invloed op de fauna

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    Aanleiding voor deze publicatie zijn de resultaten van het onderzoek naar de effecten van herstelmaatregelen op dieren van het heidelandschap. De afgelopen jaren werd steeds duidelijker dat het onderzoek en de toepassing daarvan moeten worden opgeschaald naar het niveau van het landschap. Dat is ook hier zichtbaar geworden: het gaat niet alleen over de droge en de natte heide, maar ook over vennen en over struwelen en bosranden. Kortom: het gaat over het complete heidelandschap, met al zijn variatie en (geleidelijke of abrupte) overgangen. En juist bij zo’n divers en samenhangend landschap is de fauna gebaa

    Droog Duinlandschap

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    Synaptotagmin 13 is neuroprotective across motor neuron diseases

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    In amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA), spinal and lower brainstem motor neurons degenerate, but some motor neuron subtypes are spared, including oculomotor neurons (OMNs). The mechanisms responsible for this selective degeneration are largely unknown, but the molecular signatures of resistant and vulnerable motor neurons are distinct and offer clues to neuronal resilience and susceptibility. Here, we demonstrate that healthy OMNs preferentially express Synaptotagmin 13 (SYT13) compared to spinal motor neurons. In end-stage ALS patients, SYT13 is enriched in both OMNs and the remaining relatively resilient spinal motor neurons compared to controls. Overexpression of SYT13 in ALS and SMA patient motor neurons in vitro improves their survival and increases axon lengths. Gene therapy with Syt13 prolongs the lifespan of ALS mice by 14% and SMA mice by 50% by preserving motor neurons and delaying muscle denervation. SYT13 decreases endoplasmic reticulum stress and apoptosis of motor neurons, both in vitro and in vivo. Thus, SYT13 is a resilience factor that can protect motor neurons and a candidate therapeutic target across motor neuron diseases

    Shortlist Master plan Wind Monitoring fish eggs and larvae in the southern North Sea: final report Part A en B

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    This report presents the results of twelve monthly ichthyoplankton surveys carried out from April 2010 until March 2011 in the southern North Sea. The aim of this study was to collect data on the temporal and spatial distribution of fish eggs and larvae on the Dutch Continental Shelf (NCP). However, since fish eggs and larvae are transported with the currents onto the NCP a larger area covering the majority of the southern North Sea was sampled during the surveys. Despite technical problems or bad weather conditions preventing the sampling of all planned stations during each survey, the coverage was good and the general trends in ichthyoplankton abundance became apparent. Fish eggs were found in all months but species and numbers varied per month across the southern North Sea. The highest abundance of fish eggs was found from January until May with fish eggs being found at all stations from April until July. Very few eggs were found between August and November. From December onwards abundance of eggs increased again. The pattern was the same on the NCP. In total 35 different species of fish eggs were found. Fish larvae were found in all months but species and numbers varied in a similar pattern to the fish eggs, except the highest abundance of larvae was found in December and January in the English Channel (mostly herring). Numbers of larvae in the southern North Sea increased from April until June and afterwards then gradually declined until November. After this the abundances increased again. Larvae were found at almost all stations from May until September. In October and November larvae were found at half of all the stations both in the whole sampling area and on the NCP. The patterns was the same on the NCP. In total 74 different species of fish larvae were found. Based on the results of a modelling study, a mitigating measure was issued by the Dutch authorities forbidding pile driving of offshore wind farm foundations from January to June, in order to ensure that negative effects on prey availability for birds and marine mammals within Natura 2000 areas are minimised. The results of the year-round monthly surveys show that from April until September fish larvae were found throughout the survey area, including the NCP, in varying numbers and varying species. Still in October and November larvae were found at half of the stations although at lower abundances. Even in December larvae were still found at a quarter of the stations on the NCP. Whilst the abundance of larvae was low in October and November, there are a few species with larvae present that are absent at other times of the year. These results on ichthyoplankton abundance and results of the experimental study on the effect of pile driving on fish larvae need to be combined. Ideally they should also be assessed with subsequent studies of ichthyoplankton transport and impact on the Natura 2000 sites. This unique study is the first to comprehensively sample and analyse the ichthyoplankton with monthly resolution in the southern North Sea. These data on spatial and temporal distribution of fish eggs and larvae can be used in modelling studies to assess the effects of human activities in the southern North Sea, on different fish stocks
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