905 research outputs found

    Assessing the influence of different validation protocols on Ocean Colour match-up analyses

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    Abstract Multiple approaches have been used by the Ocean Colour community for validating satellite-derived products using in situ data, with most of them derived from mainly two approaches, one suggested by Bailey and Werdell (2006) (BW06) and one suggested by Zibordi et al. (2009a) (Z09), each with a different set of quality checking and spatiotemporal collocation criteria. The question remains what sort of information is added or missed when choosing one over the other. In this work, the differences among validation approaches were determined by using a common dataset of in situ and satellite data. The match-up exercise was separated into two groups of datasets based on the spatial resolution of the sensors to be validated. Sentinel-3A/OLCI data were selected as a representation of medium spatial resolution sensors, and two validation approaches were selected to this match-up dataset. The high spatial resolution sensors were represented by Sentinel-2A/MSI data, and three validation approaches were tested. Data from the AERONET-OC network were chosen as the common in situ dataset. For Sentinel-3A/OLCI, the number of match-ups varies depending on the validation approach used. Bailey and Werdell (2006) produces 20% more match-ups for Sentinel-3A/OLCI due to its more relaxed filtering criteria compared to the criteria applied by Zibordi et al. (2009a) . The validation metrics vary between different validation methods giving a different impression of accuracy of the satellite products. Also, the satellite data selected by BW06 have a statistical distribution with a higher median and standard deviation when compared to Z09. Similar findings are also confirmed for the match-up analysis conducted for Sentinel-2A/MSI. Therefore, although a common reference dataset was used, the validation statistical results were influenced by the validation approach selected. This does not suggest that one validation protocol is better than the other, but it implies that validation statistics reported in different studies may not always be directly comparable. Additionally, it was determined that BW06 could be a better fit when trying to obtain a sufficient number of match-ups for calibration purposes in the shortest time

    3-point off-shell vertex in scalar QED in arbitrary gauge and dimension

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    We calculate the complete one-loop off-shell three-point scalar-photon vertex in arbitrary gauge and dimension for Scalar Quantum Electrodynamics. Explicit results are presented for the particular cases of dimensions 3 and 4 both for massive and massless scalars. We then propose non-perturbative forms of this vertex that coincide with the perturbative answer to order e2e^2.Comment: Uses axodra

    Geochemistry and Geochronology of the Guajira Eclogites, northern Colombia : evidence of a metamorphosed primitive Cretaceous Caribbean Island-arc

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    The chemical composition of eclogites, found as boulders in a Tertiary conglomerate from the Guajira Peninsula, Colombia suggests that these rocks are mainly metamorphosed basaltic andesites. They are depleted in LILE elements compared to MORB, have a negative Nb-anomaly and flat to enriched REE patterns, suggesting that their protoliths evolved in a subduction related tectonic setting. They show island-arc affinities and are similar to primitive islandarc rocks described in the Caribbean. The geochemical characteristics are comparable to low-grade greenschists from the nearby Etpana Terrane, which are interpreted as part of a Cretaceous intra-oceanic arc. These data support evidence that the eclogites and the Etpana terrane rocks formed from the same volcano-sedimentary sequence. Part of this sequence was accreted onto the margin and another was incorporated into the subduction channel and metamorphosed at eclogite facies conditions. 40Ar-39Ar ages of 79.2±1.1Ma and 82.2±2.5Ma determined on white micas, separated from two eclogite samples, are interpreted to be related to the cooling of the main metamorphic event. The formation of a common volcano-sedimentary protolith and subsequent metamorphism of these units record the ongoing Late Cretaceous continental subduction of the South American margin within the Caribbean intra-oceanic arc subduction zone. This gave way to an arc-continent collision between the Caribbean and the South American plates, where this sequence was exhumed after the Campanian

    Environmentally friendly analysis of emerging contaminants by pressurized hot water extraction-stir bar sorptive extraction-derivatization and gas chromatography-mass spectrometry

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    This work describes the development, optimiza- tion, and validation of a new method for the simultaneous determination of a wide range of pharmaceuticals (beta- blockers, lipid regulators ... ) and personal care products (fragrances, UV filters, phthalates ... ) in both aqueous and solid environmental matrices. Target compounds were extracted from sediments using pressurized hot water ex- traction followed by stir bar sorptive extraction. The first stage was performed at 1,500 psi during three static extrac- tion cycles of 5 min each after optimizing the extraction temperature (50 – 150 °C) and addition of organic modifiers (% methanol) to water, the extraction solvent. Next, aqueous extracts and water samples were processed using polydime- thylsiloxane bars. Several parameters were optimized for this technique, including extraction and desorption time, ionic strength, presence of organic modifiers, and pH. Fi- nally, analytes were extracted from the bars by ultrasonic irradiation using a reduced amount of solvent (0.2 mL) prior to derivatization and gas chromatography – mass spectrome- try analysis. The optimized protocol uses minimal amounts of organic solvents (<10 mL/sample) and time ( ≈ 8 h/sam- ple) compared to previous ex isting methodologies. Low standard deviation (usually below 10 %) and limits of de- tection (sub-ppb) vouch for the applicability of the method- ology for the analysis of target compounds at trace levels. Once developed, the method was applied to determin

    Drug vaping applied to cannabis: Is "Cannavaping" a therapeutic alternative to marijuana?

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    Therapeutic cannabis administration is increasingly used in Western countries due to its positive role in several pathologies. Dronabinol or tetrahydrocannabinol (THC) pills, ethanolic cannabis tinctures, oromucosal sprays or table vaporizing devices are available but other cannabinoids forms can be used. Inspired by the illegal practice of dabbing of butane hashish oil (BHO), cannabinoids from cannabis were extracted with butane gas, and the resulting concentrate (BHO) was atomized with specific vaporizing devices. The efficiency of "cannavaping," defined as the "vaping" of liquid refills for e-cigarettes enriched with cannabinoids, including BHO, was studied as an alternative route of administration for therapeutic cannabinoids. The results showed that illegal cannavaping would be subjected to marginal development due to the poor solubility of BHO in commercial liquid refills (especially those with high glycerin content). This prevents the manufacture of liquid refills with high BHO concentrations adopted by most recreational users of cannabis to feel the psychoactive effects more rapidly and extensively. Conversely, "therapeutic cannavaping" could be an efficient route for cannabinoids administration because less concentrated cannabinoids-enriched liquid refills are required. However, the electronic device marketed for therapeutic cannavaping should be carefully designed to minimize potential overheating and contaminant generation

    Open Peer Review Module (OPRM). Final Report

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    Research productivity is increasing at an unprecedented rate. Technological innovations, a surge in available computing power, and the ease with which digital information is stored and communicated is helping researchers to cross experimentation boundaries, to increase data availability, and to facilitate the transfer of knowledge. As a result, traditional research is being transformed into a dynamic and globally interconnected effort where ideas, tools and results can be made instantly accessible to the entire academic community. Institutional and multidisciplinary open access repositories play a crucial role in this emerging landscape by enabling immediate accessibility to all kinds of research output. One important element still missing from open access repositories, however, is a quantitative assessment of the hosted research items that will facilitate the process of selecting the most relevant and distinguished content. Common currently available metrics, such as number of visits and downloads, do not reflect the quality of a research work, which can only be assessed directly by peers offering their expert opinion together with quantitative ratings based on specific criteria. To address this issue we developed an Open Peer Review Module (OPRM) to be installed on existing open access repositories and offered as an overlay service. Any digital research work hosted in a compliant repository can then be evaluated by an unlimited number of peers who offer not only a qualitative assessment in the form of text, but also quantitative measures that are used to build the reputation of the research work and its authors. Crucially, this evaluation system is open and transparent. By open we mean that the full text of the peer reviews are publicly available along with the original research work. By transparent we mean that the identity of the reviewers is disclosed to the authors and to the public. In our model, openness and transparency are two elemental aspects we consider necessary to address the issue of biased or non-expert opinions, which is inherent in the anonymous peer review model, characterized by the unaccountability of reviewers. Importantly, our open peer review module includes a reviewer reputation system based on the assessment of reviews themselves by other peer reviewers. This allows a sophisticated scaling of the importance of each review on the overall assessment of a research work, based on the reputation of the reviewer. The implementation of a peer review layer on top of institutional repositories could have the potential to transform the current academic publication landscape by introducing new scholarly workflows where a research item can be openly evaluated by the world’s experts right at the institutional repository of its authors, before being submitted to an academic journal. This workflow challenges the current practices of peer review research evaluation. In most cases, journals, acting as brands in a competitive market, foster academic competition for a limited number of publication slots, instead of promoting open scholarship and collaboration. The integration of peer review in repositories will enable direct and transparent academic collaboration between authors and reviewers. In addition, the use of the OPRM will produce novel metrics directly reflecting the perceived quality of a research work by expert peers, contrary to current available altmetrics that only indirectly account for quality through usage statistics.OpenAIR

    The attitudes of European consumers toward innovation in bread; interest of the consumers toward selected quality attributes

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    16 pages, 7 tables, 4 figures.-- The definitive version is available at www3.interscience.wiley.comThe present survey is integrated in the European project entitled EU-FRESHBAKE. This three years project started in October 2006. It aims at developing innovative processes and innovative formulations for the Bake Off technology taking into consideration, energy demand of the process, nutrition parameters and overall quality of the bread. To help and to advise the project on the expectations of the European consumers toward innovation, a consumer survey has been carried out taking into consideration 1050 consumers from 5 countries (Belgium, Croatia, Spain, France and Poland). The global objectives are (i) to better understand the attitudes of the European innovations in bread and (ii) to understand the main determinants of it. Globally the key points that arose from the survey were the environmental concern and the concern regarding health; these two aspects seem to steer the attitudes of the consumer. Basically, two categories of consumers were observed; (i) frequent (daily) buyers with a focus on quality and pleasure and (ii) less frequent buyers (once a week) with a more pronounced interest in nutrition and energy (process). The first group was named the crust group and the second one the crumb group. The crumb family seems to be the one that is the most interested in the outcomes of the EU-FRESHBAKE project. This group is concerned by nutrition quality and would prefer a bread which has been done with a less energy demanding process. The “crust” group is schematically less interested in the nutrition, in the shelf life and in the energy demand of the process used to prepare the bread. The results from this survey should be handled with care due to the relative small size of the sample and to the fact that the average age of the sample was rather young.This study (report, paper, workshop…) has been carried out with financial support from the Commission of the European Communities, FP6, Thematic Area “Food quality and safety”, FOOD-2006-36302 EU-FRESH BAKE.Peer reviewe

    Adult beginner distance language learner perceptions and use of assignment feedback

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    This qualitative study examines perceptions and use of assignment feedback among adult beginner modern foreign language learners on higher education distance learning courses. A survey of responses to feedback on assignments by 43 Open University students on beginner language courses in Spanish, French, and German indicated that respondents can be classified into three groups: those who use feedback strategically by integrating it into the learning process and comparing it with, for example, informal feedback from interaction with native speakers, those who take note of feedback, but seem not to use it strategically, and those who appear to take little account of either marks or feedback. The first group proved to be the most confident and most likely to maintain their motivation in the longer term. The conclusion discusses some of the pedagogical and policy implications of the findings
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