2,035 research outputs found

    Estimating above ground net biomass change in tropical and subtropical forests: refinement of IPCC default values using forest plot data

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    As countries advance in greenhouse gas (GHG) accounting for climate change mitigation, consistent estimates of above ground biomass (AGB) net change are needed for the tropics and subtropics. Countries with limited forest monitoring capabilities rely on 2006 IPCC default AGB net change values, which are averages per ecological zone, per continent. These previous defaults come from single studies, provide no uncertainty indications, and aggregate old secondary forests and old-growth forests. In this study, we update these default values using forest plot data. In comparison with previous estimates, new values include data published from 2006 onwards, are derived from multiple sites per global ecological zone, provide measures of variation, and divide forests >20 years old into older secondary forests and old-growth forests. We compiled 176 AGB chronosequences in secondary forests and AGB net change rates from 536 permanent plots in old-growth and managed or logged forests. In this dataset, across all continents and ecozones, AGB net change rates in younger secondary forests (go years) are higher than rates in older secondary (>20 years and ≤100 years) forests and managed or logged forests, which in turn are higher than rates in old-growth forests (> 100 years). Data availability is highest for North and South America, followed by Asia then Africa. We provide a rigorous and traceable refinement of the IPCC 2006 AGB net change default rates, identify which areas in the tropics and subtropics require more research on AGB change, and reflect on possibilities for improvement as more data becomes available

    How effectively do horizontal and vertical response strategies of long-finned pilot whales reduce sound exposure from naval sonar?

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    PJW was supported with studentships of The Netherlands Ministry of Defence (grant number 032.30370/01.02) and the VSB Foundation (grant number VSB.08/228-E) and Ren e Dekeling is acknowledged for making funding possible. The 3S project was supported by the US Office of Naval Research, The Netherlands Ministry of Defence, Royal Norwegian Navy and Norwegian Ministry of Defence, and by World Wildlife Fund Norway. PLT received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged.The behaviour of a marine mammal near a noise source can modulate the sound exposure it receives. We demonstrate that two long-finned pilot whales both surfaced in synchrony with consecutive arrivals of multiple sonar pulses. We then assess the effect of surfacing and other behavioural response strategies on the received cumulative sound exposure levels and maximum sound pressure levels (SPLs) by modelling realistic spatiotemporal interactions of a pilot whale with an approaching source. Under the propagation conditions of our model, some response strategies observed in the wild were effective in reducing received levels (e.g. movement perpendicular to the source's line of approach), but others were not (e.g. switching from deep to shallow diving; synchronous surfacing after maximum SPLs). Our study exemplifies how simulations of source-whale interactions guided by detailed observational data can improve our understanding about motivations behind behaviour responses observed in the wild (e.g., reducing sound exposure, prey movement).PostprintPeer reviewe

    Dosimeter-Type NOx Sensing Properties of KMnO4 and Its Electrical Conductivity during Temperature Programmed Desorption

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    An impedimetric NOx dosimeter based on the NOx sorption material KMnO4 is proposed. In addition to its application as a low level NOx dosimeter, KMnO4 shows potential as a precious metal free lean NOx trap material (LNT) for NOx storage catalysts (NSC) enabling electrical in-situ diagnostics. With this dosimeter, low levels of NO and NO2 exposure can be detected electrically as instantaneous values at 380 °C by progressive NOx accumulation in the KMnO4 based sensitive layer. The linear NOx sensing characteristics are recovered periodically by heating to 650 °C or switching to rich atmospheres. Further insight into the NOx sorption-dependent conductivity of the KMnO4-based material is obtained by the novel eTPD method that combines electrical characterization with classical temperature programmed desorption (TPD). The NOx loading amount increases proportionally to the NOx exposure time at sorption temperature. The cumulated NOx exposure, as well as the corresponding NOx loading state, can be detected linearly by electrical means in two modes: (1) time-continuously during the sorption interval including NOx concentration information from the signal derivative or (2) during the short-term thermal NOx release

    Band - Weg interactie

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    De huidige infrastructuur van wegen waarover men zich snel en comfortabel kan verplaatsen is niet meer weg te denken uit onze maatschappij. Twee “componenten” die hierbij een belangrijke rol spelen zijn het wegdek en de band. Het contact tussen band en wegdek is mede bepalend voor de veiligheid. De rolweerstand beïnvloedt het brandstofverbruik en dus de uitstoot van uitlaatgassen. De mechanische eigenschappen en geometrie van het wegdek en de band bepalen de geluidproductie (verkeersgeluid) maar ook de mate van slijtage van beide componenten (fijn stof). Er wordt onderzoek gedaan om de veiligheid, de rolweerstand, de duurzaamheid e.d. van banden en wegdek te verbeteren. In veel gevallen wordt dit door de bandenindustrie en de wegdekproducenten afzonderlijk gedaan. Op deze manier streeft men er naar om te komen tot een optimale band en een optimaal wegdek. Maar wat optimaal is voor de band hoeft nog niet optimaal voor het wegdek te zijn. Vandaar dat voor een echt optimale combinatie van band en wegdek, onderzoek moet worden gedaan naar de gekoppelde situatie of wel naar band-weg interactie. Om dit te realiseren hebben 4 onderzoeksgroepen van de Universiteit Twente met ervaring op het gebied van wegdekken of banden de krachten gebundeld teneinde band-wegdek interactie (modelmatig en experimenteel) integraal te kunnen onderzoeke

    Developing European conservation and mitigation tools for pollination services: approaches of the STEP (Status and Trends of European Pollinators) project

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    Pollinating insects form a key component of European biodiversity, and provide a vital ecosystem service to crops and wild plants. There is growing evidence of declines in both wild and domesticated pollinators, and parallel declines in plants relying upon them. The STEP project (Status and Trends of European Pollinators, 2010-2015, www.stepproject.net) is documenting critical elements in the nature and extent of these declines, examining key functional traits associated with pollination deficits, and developing a Red List for some European pollinator groups. Together these activities are laying the groundwork for future pollinator monitoring programmes. STEP is also assessing the relative importance of potential drivers of pollinator declines, including climate change, habitat loss and fragmentation, agrochemicals, pathogens, alien species, light pollution, and their interactions. We are measuring the ecological and economic impacts of declining pollinator services and floral resources, including effects on wild plant populations, crop production and human nutrition. STEP is reviewing existing and potential mitigation options, and providing novel tests of their effectiveness across Europe. Our work is building upon existing and newly developed datasets and models, complemented by spatially-replicated campaigns of field research to fill gaps in current knowledge. Findings are being integrated into a policy-relevant framework to create evidence-based decision support tools. STEP is establishing communication links to a wide range of stakeholders across Europe and beyond, including policy makers, beekeepers, farmers, academics and the general public. Taken together, the STEP research programme aims to improve our understanding of the nature, causes, consequences and potential mitigation of declines in pollination services at local, national, continental and global scales

    Description, Host-specificity, and Strain Selectivity of the Dinoflagellate Parasite Parvilucifera sinerae sp.nov. (Perkinsozoa)

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    17 pages, 7 figures, 2 tablesA new species of parasite, Parvilucifera sinerae sp. nov., isolated froma bloomof the toxic Dinoflagellate Alexandrium minutum in the harbor of Arenys de Mar (Mediterranean Sea, Spain), is described. This species is morphologically, behaviourally, and genetically (18S rDNA sequence) different from Parvilucifera infectans, until now the only species of the genus Parvilucifera to be genetically analyzed. Sequence análisis of the 18S ribosomal DNA supported P. Sinerae as a new species placed within the Perkinsozoa and close to P. infectans. Data on the seasonal occurrence of P. sinerae, its infective rates in natural and laboratory cultures, and intra-species strain-specific Resistance are presented. Life-cycle studies in field simples showed that the dinoflagellate resting zygote (restingcyst) was resistant to infection, but the mobile zygote (planozygote) orpelli clestage (temporary cyst) became infected. The effects of Light and salinity level son the growth of P. sinerae were examined, and the results showed that low salinity levels promote both sporangial germination and higher rates of infection. Our findings on this newly described parasite point to a complex host—parasite interaction and provide valuable information that leads to a reconsideration of the biological strategy to control dinoflagellate blooms by jeans of intentional parasitic infectionsThis research was funded by the EU Project SEED (GOCE-CT-2005-003875). R.I. Figueroa work is supported by a I3P contract and E. Garcés’ work is supported by a Ramon y Cajal grant, both from the Spanish Ministry of Education and SciencePeer reviewe
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