102 research outputs found

    Deglacial upslope shift of NE Atlantic intermediate waters controlled slope erosion and cold-water coral mound formation (Porcupine Seabight, Irish margin)

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    Highlights • Holocene cold-water coral mound formation started non-synchronous in Belgica province. • Coral mounds and slope sediments record changes in intermediate water mass dynamics. • Increased turbulent bottom currents steered slope erosion and mound formation. • Internal waves at the ENAW-MOW boundary enhance energy supply and particle flux. • Transition zone between the ENAW-MOW shifted 250 m upslope during the last deglacial. Abstract Turbulent bottom currents significantly influence the formation of cold-water coral mounds and sedimentation processes on continental slopes. Combining records from coral mounds and adjacent slope sediments therefore provide an unprecedented palaeo-archive to understand past variations of intermediate water-mass dynamics. Here, we present coral ages from coral mounds of the Belgica province (Porcupine Seabight, NE Atlantic), which indicate a non-synchronous Holocene re-activation in mound formation suggested by a temporal offset of ∼2.7 kyr between the deep (start: ∼11.3 ka BP at 950 m depth) and shallow (start: ∼8.6 ka BP at 700 m depth) mounds. A similar depth-dependent pattern is revealed in the slope sediments close to these mounds that become progressively younger from 22.1 ka BP at 990 m to 12.2 ka BP at 740 m depth (based on core-top ages). We suggest that the observed changes are the consequence of enhanced bottom-water hydrodynamics, caused by internal waves associated to the re-invigoration of the Mediterranean Outflow Water (MOW) and the development of a transition zone (TZ) between the MOW and the overlying Eastern North Atlantic Water (ENAW), which established during the last deglacial. These highly energetic conditions induced erosion adjacent to the Belgica mounds and supported the re-initiation of mound formation by increasing food and sediment fluxes. The striking depth-dependent patterns are likely linked to a shift of the ENAW-MOW-TZ, moving the level of maximum energy ∼250 m upslope since the onset of the last deglaciation

    Deglacial upslope shift of NE Atlantic intermediate waters controlled slope erosion and cold-water coral mound formation (Porcupine Seabight, Irish margin)

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    Highlights • Holocene cold-water coral mound formation started non-synchronous in Belgica province. • Coral mounds and slope sediments record changes in intermediate water mass dynamics. • Increased turbulent bottom currents steered slope erosion and mound formation. • Internal waves at the ENAW-MOW boundary enhance energy supply and particle flux. • Transition zone between the ENAW-MOW shifted 250 m upslope during the last deglacial. Abstract Turbulent bottom currents significantly influence the formation of cold-water coral mounds and sedimentation processes on continental slopes. Combining records from coral mounds and adjacent slope sediments therefore provide an unprecedented palaeo-archive to understand past variations of intermediate water-mass dynamics. Here, we present coral ages from coral mounds of the Belgica province (Porcupine Seabight, NE Atlantic), which indicate a non-synchronous Holocene re-activation in mound formation suggested by a temporal offset of ∼2.7 kyr between the deep (start: ∼11.3 ka BP at 950 m depth) and shallow (start: ∼8.6 ka BP at 700 m depth) mounds. A similar depth-dependent pattern is revealed in the slope sediments close to these mounds that become progressively younger from 22.1 ka BP at 990 m to 12.2 ka BP at 740 m depth (based on core-top ages). We suggest that the observed changes are the consequence of enhanced bottom-water hydrodynamics, caused by internal waves associated to the re-invigoration of the Mediterranean Outflow Water (MOW) and the development of a transition zone (TZ) between the MOW and the overlying Eastern North Atlantic Water (ENAW), which established during the last deglacial. These highly energetic conditions induced erosion adjacent to the Belgica mounds and supported the re-initiation of mound formation by increasing food and sediment fluxes. The striking depth-dependent patterns are likely linked to a shift of the ENAW-MOW-TZ, moving the level of maximum energy ∼250 m upslope since the onset of the last deglaciation

    Wirksame Wege zur Verbesserung der Teilhabe- und Verwirklichungschancen von Kindern aus Familien in prekären Lebenslagen

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    WIRKSAME WEGE ZUR VERBESSERUNG DER TEILHABE- UND VERWIRKLICHUNGSCHANCEN VON KINDERN AUS FAMILIEN IN PREKÄREN LEBENSLAGEN Wirksame Wege zur Verbesserung der Teilhabe- und Verwirklichungschancen von Kindern aus Familien in prekären Lebenslagen / Apel, Peter (CC BY-NC-ND) ( -

    Foredrag Øko2020, Tema Grønnsaker, Landbrukets Økologikongress 2020

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    Vi har samla slides fra foredraga holdt på Landbrukets Økologikonferanse 2020 under tema Grønnsaker på Øko2020 ble arrangert 21 - 22. januar. Hovedtema for konferansen var jord. PROGRAM Grønnsaker (ikke alle foredrag er publisert) Grønnsaker Slik dyrker jeg gulrot og kålvekster, Heinrich Jung, gardbruker i Solør Ugraskontroll, Thomas Holz, NLR Falskt såbed og organisk gjødsel, Mette Thomsen, NIBIO Blomsterremsor och andra åtgärder för att gynna nyttodjur och pollinerare i grönsaksodlingar i Sverige, Elisabeth Ögren, Jordbruksverket Potensialet med biokull i grønnsakspoduksjonen, Alice Budai, NIBIO Økologiske dyrkningssystemer til grønsagsproduktion med fokus på jordens mikrobielle aktivitet, kvælstof og rodvækst, Hanne Lakkenborg Kristensen, Århus Univeritet, Danmark Slik dyrker jeg potet, Halvor Midtsundstad, gardbruker i Solør Tidligpotet til lagring – en strategi for å redusere tørråte?Anne -Kristin Løes, NORSØ

    Nutrient enrichment alters seasonal β-diversity in global grasslands

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    Intra-annual (i.e. seasonal) temporal niche partitioning is essential to the maintenance of biodiversity in many plant communities. However, understanding of how climate and global change drivers such as eutrophication influence seasonal niche partitioning in plant assemblages remains limited. We used early-season and late-season compositional data collected from 10 grassland sites around the world to explore relationships between climate variability and intra-annual species segregation (i.e. seasonal β-diversity) and to assess how nutrient enrichment alters seasonal β-diversity in plant communities. We then assessed whether changes in seasonal β-diversity in response to nutrient enrichment are underpinned by species turnover or nestedness and determined how specific functional groups (i.e. annual forbs, perennial forbs, C3 and C4 graminoids and legumes) respond to eutrophication within and across early and late sampling dates. We found a positive relationship between intra-annual temperature variability and seasonal β-diversity but observed no relationship between intra-annual precipitation variability and seasonal β-diversity. Nutrient enrichment increased seasonal β-diversity and increased turnover of species between early- and late-season communities. Nutrient enrichment reduced the abundance of C4 graminoids and legumes within and across sampling timepoints and eliminated intra-annual differences in these groups. In contrast, nutrient enrichment resulted in seasonal differences in C3 graminoids, which were not observed in control conditions and increased abundance of C3 graminoids and annual forbs within and across early and late sampling dates. Synthesis: Our understanding of how grasslands respond to various components of global change is primarily based on studies that document community changes at inter-annual scales. Using early-season and late-season compositional data from 10 grassland sites around the world, we show that nutrient enrichment increases seasonal β-diversity and alters intra-annual dynamics of specific functional groups in unique ways

    Local Translation in Primary Afferent Fibers Regulates Nociception

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    Recent studies have demonstrated the importance of local protein synthesis for neuronal plasticity. In particular, local mRNA translation through the mammalian target of rapamycin (mTOR) has been shown to play a key role in regulating dendrite excitability and modulating long-term synaptic plasticity associated with learning and memory. There is also increased evidence to suggest that intact adult mammalian axons have a functional requirement for local protein synthesis in vivo. Here we show that the translational machinery is present in some myelinated sensory fibers and that active mTOR-dependent pathways participate in maintaining the sensitivity of a subpopulation of fast-conducting nociceptors in vivo. Phosphorylated mTOR together with other downstream components of the translational machinery were localized to a subset of myelinated sensory fibers in rat cutaneous tissue. We then showed with electromyographic studies that the mTOR inhibitor rapamycin reduced the sensitivity of a population of myelinated nociceptors known to be important for the increased mechanical sensitivity that follows injury. Behavioural studies confirmed that local treatment with rapamycin significantly attenuated persistent pain that follows tissue injury, but not acute pain. Specifically, we found that rapamycin blunted the heightened response to mechanical stimulation that develops around a site of injury and reduced the long-term mechanical hypersensitivity that follows partial peripheral nerve damage - a widely used model of chronic pain. Our results show that the sensitivity of a subset of sensory fibers is maintained by ongoing mTOR-mediated local protein synthesis and uncover a novel target for the control of long-term pain states

    Expanding the diversity of mycobacteriophages: insights into genome architecture and evolution.

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    Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists

    Making Sense of Institutional Change in China: The Cultural Dimension of Economic Growth and Modernization

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    African hydroclimatic variability during the last 2000 years

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