96 research outputs found

    Antifreeze Proteins in the Primary Urine of Larvae of the Beetle \u3cem\u3eDendroides canadensis\u3c/em\u3e

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    To avoid freezing while overwintering beneath the bark of fallen trees, Dendroides canadensis (Coleoptera: Pyrochroidae) larvae produce a family of antifreeze proteins (DAFPs) that are transcribed in specific tissues and have specific compartmental fates. DAFPs and associated thermal hysteresis activity (THA) have been shown previously in hemolymph and midgut fluid, but the presence of DAFPs has not been explored in primary urine, a potentially important site that can contain endogenous ice-nucleating compounds that could induce freezing. A maximum mean THA of 2.65±0.33°C was observed in primary urine of winter-collected D. canadensis larvae. THA in primary urine increased significantly through autumn, peaked in the winter and decreased through spring to levels of 0.2–0.3°C in summer, in a pattern similar to that of hemolymph and midgut fluid. THA was also found in hindgut fluid and excreted rectal fluid, suggesting that these larvae not only concentrate AFPs in the hindgut, but also excrete AFPs from the rectal cavity. Based on dafp transcripts isolated from Malpighian tubule epithelia, cDNAs were cloned and sequenced, identifying the presence of transcripts encoding 24 DAFP isoforms. Six of these Malpighian tubule DAFPs were known previously, but 18 are new. We also provide functional evidence that DAFPs can inhibit ice nucleators present in insect primary urine. This is potentially critical because D. canadensis larvae die if frozen, and therefore ice formation in any body fluid, including the urine, would be lethal

    Holocene dinoflagellate cysts as salinity indicators from the southwestern Black Sea

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    Dinoflagellate cysts are used as a proxy for the reconstruction of the salinity variations during Holocene times in the southwestern Black Sea. Core GeoB 7625-2, located 50 km northeast of the mouth of the Sakarya River, was sampled with a 200 year resolution between 0.25 ka BP – 7.8 ka BP. In the lower part of the core, some extra crucial intervals were sampled with a higher resolution for the determination of the reconnection between the Black Sea and the Sea of Marmara. The drastic change in the dinoflagellate cyst assemblage – from a freshbrackish water to saltwater association – is observed between ~9.6 and ~8.1 ka BP, which is earlier than observed in the dinocyst studies of e.g. Marret et al. (in press), Mudie et al. (2001) and Wall & Dale (1973). This could indicate a diachronic salinification of the Black Sea. The fresh to brackish water indicator species are Spiniferites cruciformis form 1-4 and Pyxidinopsis psilata, while the most important saltwater species are Lingulodinium machaerophorum and cysts of Pentapharsodinium dalei. The first occurrence of euryhaline species took place synchronous with a sea level rise and an increase in productivity. The process length of L. machaerophorum, a salinity proxy, indicates a gradual salinity increase. This assumes a gradual reconnection between the Black Sea and the Sea of Marmara, which conflicts with the catastrophic flood (Noah’s Flood Hypothesis) introduced by Ryan et al. (1997, 2003). The 500 to 800 year cycles observed in the sedimentary record by Lamy et al. (2006), and related to the North Atlantic Oscillation, were not only recorded by us in the salinity proxy but also in dinoflagellate cyst abundances (productivity). The observed productivity changes are furthermore related to the sedimentation rate: the increase in precipitation in Anatolia possibly results in a higher sediment discharge leading to a better preservation of the organic-walled microfossils. This makes it difficult to determine whether the fluctuations of the dinocysts/gram ratio are the result of fluctuations in productivity or are an artefact due to changes in the sedimentation rate. Furthermore, it is shown that Peridinium ponticum, a species restricted geographically to the Black Sea, is a good proxy for the reconstruction of Holocene salinity variations since its relative abundance fluctuates synchronous with the process length variations of L. machaeorophorum

    Invasive Alien Species in Belgian marine waters: an information platform and checklist for science and policy support

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    Since 2006, the ‘VLIZ Alien Species Consortium’ has collected data and information on species that were introduced by humans in marine and brackish habitats and have established reproducing populations in the study area. The consortium consists of a network of experts in marine and brackish environments in Belgium, representing more than 22 different institutions and supported by a secretariat hosted at Flanders Marine Institute VLIZ. Evidence on invasiveness is reported for 12 of the 73 alien species that are currently included in the checklist for the study area (October 2014). The network brings together scientific information from distributed sources in a central platform. It is a first step to developing an evidence-based approach to inform environmental policy objectives for Belgian marine waters and support effective measures to address invasive alien species in the study area. The information platform and species checklist are presented, approaches for collection and integration of information are described, and opportunities for collaboration between information systems at different governance levels are briefly discussed

    Three Decades of Customer Value Research: Paradigmatic Roots and Future Research Avenues

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    The last three decades have witnessed a resurgence of research on the topic of customer value. In search of a comprehensive integration and analysis of this research—including conceptualization, operationalization, and measurement—we examined the myriad journal publications on the construct. We acknowledge that while some of the literature can be fully integrated, other parts are more difficult because they represent three different paradigms: positivist, interpretive, and social constructionist. We begin by briefly describing these three paradigms. Next, we detail the many studies representing the positivist paradigm, literature capturing customer value from just the customer’s perspective and using deductive logic. We designate the second paradigm as interpretive, in that researchers are interested in understanding the subjective nature of customer value along with its emergence through inductive logic. The third paradigm, the social constructionist, frames customer value as emerging from value co-creation practices in complex ecosystems. Building upon the commonalities and differences among research studies stemming from the positivist, interpretive, and social constructionist paradigms, we propose how researchers can complement one another to move the customer value field forward

    Cyberinfrastructure Deployments on Public Research Clouds Enable Accessible Environmental Data Science Education

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    Modern science depends on computers, but not all scientists have access to the scale of computation they need. A digital divide separates scientists who accelerate their science using large cyberinfrastructure from those who do not, or who do not have access to the compute resources or learning opportunities to develop the skills needed. The exclusionary nature of the digital divide threatens equity and the future of innovation by leaving people out of the scientific process while over-amplifying the voices of a small group who have resources. However, there are potential solutions: recent advancements in public research cyberinfrastructure and resources developed during the open science revolution are providing tools that can help bridge this divide. These tools can enable access to fast and powerful computation with modest internet connections and personal computers. Here we contribute another resource for narrowing the digital divide: scalable virtual machines running on public cloud infrastructure. We describe the tools, infrastructure, and methods that enabled successful deployment of a reproducible and scalable cyberinfrastructure architecture for a collaborative data synthesis working group in February 2023. This platform enabled 45 scientists with varying data and compute skills to leverage 40,000 hours of compute time over a 4-day workshop. Our approach provides an open framework that can be replicated for educational and collaborative data synthesis experiences in any data- and compute-intensive discipline
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