104 research outputs found

    Monetary policy and bank distress: an integrated micro-macro approach

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    Evidence on the interdependency between monetary policy and the state of the banking system is scarce. We suggest an integrated micro-macro approach with two core virtues. First, we measure the probability of bank distress directly at the bank level. Second, we integrate a microeconomic hazard model for bank distress and a standard macroeconomic model. The advantage of this approach is to incorporate micro information, to allow for non-linearities and to permit general feedback effects between bank distress and the real economy. We base the analysis on German bank and macro data between 1995 and 2004. Our results confirm the existence of a relationship between monetary policy and bank distress. A monetary contraction increases the mean probability of distress. This effect disappears when neglecting micro effects, underlining the crucial importance of the former. Distress responses are economically most significant for weak distress events and at times when capitalization is low. --Stress testing,bank distress,monetary policy

    Ice Algae-Produced Carbon Is Critical for Overwintering of Antarctic Krill Euphausia superba

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    Antarctic krill Euphausia superba (“krill”) constitute a fundamental food source for Antarctic seabirds and mammals, and a globally important fisheries resource. The future resilience of krill to climate change depends critically on the winter survival of young krill. To survive periods of extremely low production by pelagic algae during winter, krill are assumed to rely partly on carbon produced by ice algae. The true dependency on ice algae-produced carbon, however, is so far unquantified. This confounds predictions on the future resilience of krill stocks to sea ice decline. Fatty acid (FA) analysis, bulk stable isotope analysis (BSIA), and compound-specific stable isotope analysis (CSIA) of diatom- and dinoflagellate-associated marker FAs were applied to quantify the dependency of overwintering larval, juvenile, and adult krill on ice algae-produced carbon (αIce) during winter 2013 in the Weddell-Scotia Confluence Zone. Our results demonstrate that the majority of the carbon uptake of the overwintering larval and juvenile krill originated from ice algae (up to 88% of the carbon budget), and that the dependency on ice algal carbon decreased with ontogeny, reaching <56% of the carbon budget in adults. Spatio-temporal variability in the utilization of ice algal carbon was more pronounced in larvae and juvenile krill than in adults. Differences between αIce estimates derived from short- vs. long-term FA-specific isotopic compositions suggested that ice algae-produced carbon gained importance as the winter progressed, and might become critical at the late winter-spring transition, before the phytoplankton bloom commences. Where the sea ice season shortens, reduced availability of ice algae might possibly not be compensated by surplus phytoplankton production during wintertime. Hence, sea ice decline could seriously endanger the winter survival of recruits, and subsequently overall biomass of krill

    The influence of Arctic Fe and Atlantic fixed N on summertime primary production in Fram Strait, North Greenland Sea

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    Climate change has led to a ~ 40% reduction in summer Arctic sea-ice cover extent since the 1970s. Resultant increases in light availability may enhance phytoplankton production. Direct evidence for factors currently constraining summertime phytoplankton growth in the Arctic region is however lacking. GEOTRACES cruise GN05 conducted a Fram Strait transect from Svalbard to the NE Greenland Shelf in summer 2016, sampling for bioessential trace metals (Fe, Co, Zn, Mn) and macronutrients (N, Si, P) at ~ 79°N. Five bioassay experiments were conducted to establish phytoplankton responses to additions of Fe, N, Fe + N and volcanic dust. Ambient nutrient concentrations suggested N and Fe were deficient in surface seawater relative to typical phytoplankton requirements. A west-to-east trend in the relative deficiency of N and Fe was apparent, with N becoming more deficient towards Greenland and Fe more deficient towards Svalbard. This aligned with phytoplankton responses in bioassay experiments, which showed greatest chlorophyll-a increases in + N treatment near Greenland and + N + Fe near Svalbard. Collectively these results suggest primary N limitation of phytoplankton growth throughout the study region, with conditions potentially approaching secondary Fe limitation in the eastern Fram Strait. We suggest that the supply of Atlantic-derived N and Arctic-derived Fe exerts a strong control on summertime nutrient stoichiometry and resultant limitation patterns across the Fram Strait region.S.K. was financed by GEOMAR and the German Research Foundation (DFG Award Number AC 217/1-1 to E.P.A). T.J.B. acknowledges funding from a Marie Skłodowska-Curie Postdoctoral European Fellowship (OceanLiNES; Project ID 658035). Open Access funding provided by Projekt DEAL

    Ice-fuelled food webs in the Polar Oceans

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    The Arctic Ocean is undergoing substantial warming and sea ice loss which are likely to cause changes in primary production, export fluxes and productivity of the Arctic marine ecosystems. Yet, we lack sufficient information about the ecosystem productivity, organic carbon cycling and cryo-pelago-benthic coupling processes in the Arctic Ocean. Particularly such information is scarce for deep Arctic basins and the spring to summer transition time. Our aim was to provide carbon budget estimations under different regimes and bloom development stages in the region north of Svalbard. We conducted ecological and biogeochemical early spring process studies in sea ice covered areas, from the shelf to the basins of the European Arctic margin and on the Yermak Plateau during the TRANSSIZ cruise PS 92 on the ice breaker R/V Polarstern in May/June 2015. We identified the potential characteristics of carbon production of primary producers in the sea ice and water column, and secondary production of zooplankton and benthos. We looked into the organic carbon production fate and export, including respiration and burial, as well as identified similarities and differences in ecosystem functioning along topography- , sea ice- and water mass-related gradients. This scientific initiative was undertaken by Arctic in Rapid Transition (ART) International Arctic Science Committee (IASC) network

    Accretion in Evolved and Transitional Disks in Cep OB2: Looking for the Origin of the Inner Holes

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    We present accretion rates for a large number of solar-type stars in the Cep OB2 region, based on U band observations. Our study comprises 95 members of the ~4 Myr-old cluster Tr 37 (including 20 "transition" objects; TO), as well as the only CTTS in the ~12 Myr-old cluster NGC 7160. The stars show different disk morphologies, with the majority of them having evolved and flattened disks. The typical accretion rates are about one order of magnitude lower than in regions aged 1-2 Myr, and we find no strong correlation between disk morphology and accretion rates. Although half of the TO are not accreting, the median accretion rates of normal CTTS and accreting "transition" disks are similar (~3 10^{-9} and 2 10^{-9} Msun/yr, respectively). Comparison with other regions suggests that the TO observed at different ages do not necessarily represent the same type of objects, which is consistent with the fact that the different processes that can lead to reduced IR excess/inner disk clearing (e.g., binarity, dust coagulation/settling, photoevaporation, giant planet formation) do not operate on the same timescales. Accreting TO in Tr 37 are probably suffering strong dust coagulation/settling. Regarding the equally large number of non-accreting TO in the region, other processes, like photoevaporation, the presence of stellar/substellar companions, and/or giant planet formation may account for their "transitional" SEDs and negligible accretion rates.Comment: 37 pages, 5 figures, 6 tables Accepted by Ap

    The genomes of two key bumblebee species with primitive eusocial organization

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    Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation

    Evidence for Regulated Interleukin-4 Expression in Chondrocyte-Scaffolds under In Vitro Inflammatory Conditions

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    OBJECTIVE: To elucidate the anti-inflammatory and anabolic effects of regulated expression of IL-4 in chondrocyte-scaffolds under in vitro inflammatory conditions. METHODS: Mature articular chondrocytes from dogs (n = 3) were conditioned through transient transfection using pcDNA3.1.cIL-4 (constitutive) or pCOX-2.cIL-4 (cytokine-responsive) plasmids. Conditioned cells were seeded in alginate microspheres and rat-tail collagen type I matrix (CaReS®) to generate two types of tissue-engineered 3-dimensional scaffolds. Inflammatory arthritis was simulated in the packed chondrocytes through exogenous addition of recombinant canine (rc) IL-1β (100 ng/ml) plus rcTNFα (50 ng/ml) in culture media for 96 hours. Harvested cells and culture media were analyzed by various assays to monitor the anti-inflammatory and regenerative (anabolic) properties of cIL-4. RESULTS: cIL-4 was expressed from COX-2 promoter exclusively on the addition of rcIL-1β and rcTNFα while its expression from CMV promoter was constitutive. The expressed cIL-4 downregulated the mRNA expression of IL-1β, TNFα, IL-6, iNOS and COX-2 in the cells and inhibited the production of NO and PGE(2) in culture media. At the same time, it up-regulated the expression of IGF-1, IL-1ra, COL2a1 and aggrecan in conditioned chondrocytes in both scaffolds along with a diminished release of total collagen and sGAG into the culture media. An increased amount of cIL-4 protein was detected both in chondrocyte cell lysate and in concentrated culture media. Neutralizing anti-cIL-4 antibody assay confirmed that the anti-inflammatory and regenerative effects seen are exclusively driven by cIL-4. There was a restricted expression of IL-4 under COX-2 promoter possibly due to negative feedback loop while it was over-expressed under CMV promoter (undesirable). Furthermore, the anti-inflammatory /anabolic outcomes from both scaffolds were reproducible and the therapeutic effects of cIL-4 were both scaffold- and promoter-independent. CONCLUSIONS: Regulated expression of therapeutic candidate gene(s) coupled with suitable scaffold(s) could potentially serve as a useful tissue-engineering tool to devise future treatment strategies for osteoarthritis

    Biomarker-based H-Print quantifies the composition of mixed sympagic and pelagic algae consumed by Artemia sp.

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    publisher: Elsevier articletitle: Biomarker-based H-Print quantifies the composition of mixed sympagic and pelagic algae consumed by Artemia sp. journaltitle: Journal of Experimental Marine Biology and Ecology articlelink: http://dx.doi.org/10.1016/j.jembe.2016.12.007 content_type: article copyright: © 2016 Elsevier B.V. All rights reserved
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