237 research outputs found

    Surface-induced charge state conversion of nitrogen-vacancy defects in nanodiamonds

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    We present a study of the charge state conversion of single nitrogen-vacancy (NV) defects hosted in nanodiamonds (NDs). We first show that the proportion of negatively-charged NV−^{-} defects, with respect to its neutral counterpart NV0^{0}, decreases with the size of the ND. We then propose a simple model based on a layer of electron traps located at the ND surface which is in good agreement with the recorded statistics. By using thermal oxidation to remove the shell of amorphous carbon around the NDs, we demonstrate a significant increase of the proportion of NV−^{-} defects in 10-nm NDs. These results are invaluable for further understanding, control and use of the unique properties of negatively-charged NV defects in diamondComment: 6 pages, 4 figure

    Feature integration in natural language concepts

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    Two experiments measured the joint influence of three key sets of semantic features on the frequency with which artifacts (Experiment 1) or plants and creatures (Experiment 2) were categorized in familiar categories. For artifacts, current function outweighed both originally intended function and current appearance. For biological kinds, appearance and behavior, an inner biological function, and appearance and behavior of offspring all had similarly strong effects on categorization. The data were analyzed to determine whether an independent cue model or an interactive model best accounted for how the effects of the three feature sets combined. Feature integration was found to be additive for artifacts but interactive for biological kinds. In keeping with this, membership in contrasting artifact categories tended to be superadditive, indicating overlapping categories, whereas for biological kinds, it was subadditive, indicating conceptual gaps between categories. It is argued that the results underline a key domain difference between artifact and biological concepts

    Doing marine spatial zoning in coastal marine tropics: Palawan’s Environmental Critical Areas Network (ECAN)

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    This is the final version. Available from Elsevier via the DOI in this record. Zoning is an important tool in marine spatial planning (MSP) for balancing the multi-uses of the marine environment. Whilst mainly developed conceptually and implemented in Europe and North America, marine zoning is becoming a popular tool for addressing diverse coastal marine issues in the tropics. However, we know little about how it is being implemented in practice in that context. In this study, we analysed the factors and strategies that enable and hinder the establishment of marine zoning in the low-income tropics through a case study of the 26-year history of the development of the Environmental Critical Areas Network (ECAN) in Palawan, Philippines. We employed two participatory methods: Innovation Histories to investigate how implementation barriers and opportunities change over time, and the Net-Map method to reveal the social relations and power distributions that enabled, blocked, and stalled its implementation. We found that MSP can be durable in these contexts when institutionalised in national law and adopted by local co-coordinative bodies, yet it remains an externally-driven agenda. Our study shows that the scaling up of zoning does not necessarily help resolve conflicts around marine and coastal space, and highlights the importance and influence of the political economy on MSP implementation and outcomes. We conclude that MSP's insensitivity to contextual power relations and politics raises concerns over social inclusivity, equity and justice. Moving forward, MSP implemented in the tropics needs to make conflicts, trade-offs and power distributions explicit at the outset through participatory decision-making that involves and empowers all stakeholders from the early stages of initiatives.United Kingdom Research and InnovationGlobal Challenges Research Fun

    Hydrostatic strain enhancement in laterally confined SiGe nanostripes

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    Strain-engineering in SiGe nanostructures is fundamental for the design of optoelectronic devices at the nanoscale. Here we explore a new strategy, where SiGe structures are laterally confined by the Si substrate, to obtain high tensile strain avoiding the use of external stressors, and thus improving the scalability. Spectro-microscopy techniques, finite element method simulations and ab initio calculations are used to investigate the strain state of laterally confined Ge-rich SiGe nano-stripes. Strain information is obtained by tip enhanced Raman spectroscopy with an unprecedented lateral resolution of ~ 30 nm. The nano-stripes exhibit a large tensile hydrostatic strain component, which is maximum at the center of the top free surface, and becomes very small at the edges. The maximum lattice deformation is larger than the typical values of thermally relaxed Ge/Si(001) layers. This strain enhancement originates from a frustrated relaxation in the out-of-plane direction, resulting from the combination of the lateral confinement induced by the substrate side walls and the plastic relaxation of the misfit strain in the (001) plane at the SiGe/Si interface. The effect of this tensile lattice deformation at the stripe surface is probed by work function mapping, performed with a spatial resolution better than 100 nm using X-ray photoelectron emission microscopy. The nano-stripes exhibit a positive work function shift with respect to a bulk SiGe alloy, quantitatively confirmed by electronic structure calculations of tensile strained configurations. The present results have a potential impact on the design of optoelectronic devices at a nanometer length scale.Comment: 40 pages, 11 figures, submitted to Physical Review

    Efficacy of trabectedin in metastatic solitary fibrous tumor

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    Solitary fibrous tumor is a rare tumor type and has an unpredictable course. Local recurrence rate varies between 9 and 19%, and rate of metastatic involvement between 0 and 36 %. It is characterized by a typical architecture and immuno-histochemistry tests. The most important prognostic factor is the complete resection of primary tumor. Treatment of recurrences is not clearly established. If a solitary fibrous tumor is too advanced to allow surgical resection, radiotherapy and chemotherapy may be used. The most often used drugs are doxorubicine and\or ifosfamide. We report the case of man with metastatic solitary fibrous tumor treated with trabectedin, administered at a dose of 1.5 mg/m² every 3 weeks. After 3 cycles, metastases had significantly decreased. Recurrence of the disease was demonstrated 8 months after the start of trabectedin. This case shows that trabectedin is a possible treatment option

    Polycentricity in practice: Marine governance transitions in Southeast Asia

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    This is the final version. Available from Elsevier via the DOI in this record. Environmental governance systems are expanding in size and complexity as they become more integrated and ecosystem-based. In doing so, governance transitions often involve more actors and knowingly or unknowingly alter the autonomy of actors to make decisions, and thereby the ability of the governance system to self-organise. In other words, these governance systems are becoming increasingly polycentric, moving towards an institutional structure that is reported to confer a number of benefits to social-ecological systems. This article adds to a growing body of evidence on polycentric environmental governance in practice. It adds nuance to the normative and apolitical portrayals of governance transitions in general, and transitions towards more polycentric forms of governance in particular. We analyse the relations amongst actors and historical development of four large-scale marine governance systems in Southeast Asia to understand how context, particularly power, shapes the emergence and evolution of polycentric marine governance in practice. Our data indicate that transitions towards increased polycentricity do increase diversity and autonomy of decision-making centres, which can enable more innovation or flexibility to respond to changing circumstances. However, these innovations do not always underpin sustainability and equity. Coordination mechanisms are critical for channelling the power dynamics that emerge among diverse actors towards sustainability. Yet, in these emergent, ad hoc polycentric governance arrangements such mechanisms remained nascent, ineffective, or inactive. The transaction costs involved in co-ordinating a semi-autonomous polycentric system are seemingly difficult to overcome in low- to middle-income contexts and need investment in resources and accountability mechanisms.United Kingdom Research and InnovationUniversiti Malay

    FibroMeters: a family of blood tests for liver fibrosis

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    SummaryFibroMeters are blood tests for liver fibrosis with several specificities: two main diagnostic targets (fibrosis stage and area of fibrosis); adaptation to specific causes; and results confirmed by an expert system. Thus, FibroMeters comprise six different tests: one for staging and one for quantitation of liver fibrosis in each of the three main causes of chronic liver disease—chronic viral hepatitis, alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). FibroMeters display a high overall diagnostic accuracy and are the only tests to correctly classify 100% of HCV patients without fibrosis or with cirrhosis. They have 90% predictive values in a higher proportion of patients than with other usual blood tests. A 90% correct classification is available in 100% of HCV patients with the following reliable diagnostic intervals: F0/1, F1/2, F2±1, F3±1. In real-life conditions, the reproducibility of FibroMeters is higher than that of liver biopsy or ultrasonographic elastometry. FibroMeters are robust tests with the most stable diagnostic performance across different centers. Optional tests are also available, such as a specific one for cirrhosis, which has a diagnostic accuracy of 93.0% (AUROC: 0.92) and a 100% positive predictive value for diagnosis of HCV cirrhosis. Determination by FibroMeters of the area of fibrosis – the only direct, non-invasive, quantitative measurement of liver fibrosis – are especially useful for following-up cirrhosis as it correlates well with clinical events. FibroMeters are also very accurate in HVB or HIV-HCV co-infected patients. The tests specific for ALD and NAFLD also have a high diagnostic accuracy (AUROCs: 0.96 and 0.94, respectively, for significant fibrosis)

    Pilot optical alignment

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    PILOT (Polarized Instrument for Long wavelength Observations of the Tenuous interstellar medium) is a balloonborne astronomy experiment designed to study the polarization of dust emission in the diffuse interstellar medium in our Galaxy. The PILOT instrument allows observations at wavelengths 240 μm and 550 μm with an angular resolution of about two arcminutes. The observations performed during the two first flights performed from Timmins, Ontario Canada, and from Alice-springs, Australia, respectively in September 2015 and in April 2017 have demonstrated the good performances of the instrument. Pilot optics is composed of an off axis Gregorian type telescope combined with a refractive re-imager system. All optical elements, except the primary mirror, which is at ambient temperature, are inside a cryostat and cooled down to 3K. The whole optical system is aligned on ground at room temperature using dedicated means and procedures in order to keep the tight requirements on the focus position and ensure the instrument optical performances during the various phases of a flight. We’ll present the optical performances and the firsts results obtained during the two first flight campaigns. The talk describes the system analysis, the alignment methods, and finally the inflight performances
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