401 research outputs found

    Measuring the quality of maximin space-filling designs

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    12 pagesWe present here a new index for measuring the quality of maximin space-filling design for computer experiments. This index is based on a very accurate approximation of the distribution of the minimum distance for uniform designs. Expressions are explicitly given in terms of closed polynomial forms for any Lp distances, including L2, L1 and Chebyshev distances. When the size of the design or the dimension of the space is large, approximations through extreme value theory are exhibited. Some illustrations of our index are presented on simulated data and on a real problem

    Multi-Objective Design and Optimisation of Urban Energy Systems

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    Product Description Inspired by the leading authority in the field, the Centre for Process Systems Engineering at Imperial College London, this book includes theoretical developments, algorithms, methodologies and tools in process systems engineering and applications from the chemical, energy, molecular, biomedical and other areas. It spans a whole range of length scales seen in manufacturing industries, from molecular and nanoscale phenomena to enterprise–wide optimization and control. As such, this will appeal to a broad readership, since the topic applies not only to all technical processes but also due to the interdisciplinary expertise required to solve the challenge. The ultimate reference work for years to come. From the Back Cover This fifth volume in the series is the first comprehensive source on energy systems engineering for the process industries. As such, it combines key contributions from leading research groups to form a single source of vital information otherwise dispersed among specialized journals. Inspired by the leading authority in the field, the Centre for Process Systems Engineering at Imperial College London, this interdisciplinary work explores new technologies of sustainable energy sources and their optimization as energy sufficient systems. The innovative technologies thus covered are crucial for the continued growth of already established multi–billion–dollar commercial markets: oil and gas, petrochemicals, pharmaceuticals and fine chemicals, food and beverage and consumer goods. From the contents: ∗ Polygeneration systems engineering ∗ Integrated oil & gas optimization ∗ Technologies for hydrogen production and storage ∗ Wind farm modeling, control and optimization ∗ Thermo–economic design ∗ Energy efficiency and carbon footprint reduction ∗ Energy systems solutions in the pulp and paper industry ∗ CO2 capture from natural gas ∗ Hydrogen infrastructure design and optimization ∗ Chance–constrained optimization of investment planning problems in the electric power industry For chemical, process and automation engineers, as well as those working in measurement and control, and for lecturers in these fields, this is the ultimate reference work for years to come

    Safety and Feasibility of Hypnosis-Induced Sleep Endoscopy in Obstructive Sleep Apnea Patients.

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    peer reviewed[en] BACKGROUND: Hypnosis was never used in sleep endoscopy assessment of obstructive sleep apnea syndrome (OSAS). The aim of the study was to assess the feasibility, safety, and patient satisfaction of hypnosis-induced sleep endoscopy (HISE). METHODS: From January to July 2021, 24 adults with moderate-to-severe OSAS at the polysomnography were included in the HISE protocol. The following outcomes were evaluated by the otolaryngologist and the hypnotherapist: safety, feasibility, and performance. The patient outcomes were assessed through a patient-reported outcome questionnaire assessing hypnosis acceptance, stress, anxiety, nasofibroscopy examination pain, and discomfort. RESULTS: Twenty-three patients completed the evaluations (16 males). The mean age of patients was 50.8 years. The nasofibroscopy was well-tolerated with low levels of stress during the HISE. Otolaryngologist adequately completed the VOTE scoring in 22 patients (95.7%). Hypnosis was ineffective in one patient because he felt pain during the nasofibroscopy procedure due to an important septal deviation. The hypnotherapist reported adequate satisfaction outcomes, with better results for trance compliance compared to other steps. There were no adverse effects or complications. The percentage of snoring was negatively associated with the level of consciousness during hypnosis (p = 0.012). The easiness of nasofibroscopy was positively associated with the levels of muscle relaxation (p = 0.036) and consciousness (P = 0.002). CONCLUSION: HISE is an effective alternative approach for the work-up of OSAS. Future controlled studies are needed to compare HISE with drug-induced sleep endoscopy and assess the cost-effective outcomes of both approaches

    Characterisation of iron (II) sulfides in wet archaeological woods: the wreck of Mandirac (IV th century, antique ports of Narbonne, France)

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    International audienceThe wreck of Mandirac (Narbonne, France, IV century) was excavated in 2013 and 2014 from waterlogged soil. A magnetic prospection campaign performed in 2014 revealed that the wood was abnormally magnetic. A plank extracted from the hull, containing an iron nail, was analysed using Environmental Scanning Electron Microscopy, micro-Raman spectroscopy, X-Ray diffraction and magnetic characterization methods in order to identify the mineral composition inside the wood and of the nail. Results revealed an accumulation of greigite and pyrite in the wood around the nail, where the pH was measured below 3. The nail was completely corroded into pyrite and siderite, with no metal left. Marcasite was also identified far from the nail, where the pH was measured around 5. Greigite was the only phase responsible of the magnetic signal emitted from the wood and proved to be present in varying amounts throughout the entire wreck. The iron sulfides were probably formed via anaerobic sulphidogenic bacteria influenced corrosion processes, which occurred on the nails. These results are very different from those obtained from more recent shipwrecks (XIX century). So the nature of these iron sulfides in wet archaeological woods is discussed

    Mental Health Symptoms and Work-Related Stressors in Hospital Midwives and NICU Nurses: A Mixed Methods Study.

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    Hospital midwives and neonatal intensive care (NICU) nurses frequently encounter work-related stressors and are therefore vulnerable to developing mental health problems, such as secondary traumatic stress, burnout, anxiety, and depression. However, so far, the exact nature of these work-related stressors (traumatic vs. non-traumatic stressors) has not been investigated. This concurrent triangulation mixed methods cross-sectional study aimed to compare mental health symptoms in hospital midwives and NICU nurses, and to identify and compare work-related traumatic and non-traumatic stressors for both professional groups. 122 midwives and 91 NICU nurses of two Swiss university hospitals completed quantitative measures (Secondary Traumatic Stress Scale, STSS; Hospital Anxiety and Depression Scale, HADS; Maslach Burnout Inventory, MBI) and one qualitative question in an online survey. When controlling for socio-demographic variables, NICU nurses had a higher STSS total score and higher STSS subscales scores and less HADS anxiety subscale scores than hospital midwives. Work-related stressors were classified into five themes: "Working environment," "Nursing/midwifery care," "Dealing with death and dying," "Case management" and "Others." Forty-six (46.3%) percent of these were classified as traumatic work-related stressors. NICU nurses reported more traumatic stressors in their working environment but no other differences between professional groups regarding the total number of work-related traumatic vs. non-traumatic stressors were found. Measures, such as teaching strategies to amend the subjective appraisal of the traumatic stressors or providing time to recover in-between frequently occurring work-related traumatic stressors might not only improve the mental health of professionals but also decrease sick leave and improve the quality of patient care

    Assemblages bois-fer et biocorrosion : étude des sulfures de fer formés en conditions anoxiques dans des bois d'épaves

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    International audienceLes consĂ©quences de la corrosion des renforts de fer dans les assemblages de bois peuvent compromettre la durabilitĂ© d'une structure. Si le bois est gorgĂ© d'eau, les conditions Ă  la surface du mĂ©tal deviennent anoxiques. La prĂ©sence de fer et l'activitĂ© microbiologique favorisĂ©e par la prĂ©sence de matiĂšre organique font des systĂšmes composites bois-fer des milieux propices Ă  l'apparition de sulfures de fer. Or ces derniers se transforment soit en milieux anaĂ©robies sulfurĂ©s, soit lorsque l'oxygĂšne diffuse dans le bois, soit lors d'une remise Ă  l'air de la structure, avec pour consĂ©quence de contribuer Ă  la dĂ©gradation du bois. Afin de mieux comprendre les mĂ©canismes impliquĂ©s, nous Ă©tudions des bois d'Ă©paves archĂ©ologiques. Cet article sera illustrĂ© par des exemples d'Ă©poques rĂ©centes (18 Ăš s. 19 Ăš s.) et antiques et par une approche analytique multi-techniques originale. La mackinawite, la greigite et la pyrite ont Ă©tĂ© identifiĂ©es et il semble que la nature des sulfures de fer prĂ©sents soit liĂ©e Ă  l'Ăąge du vestige conformĂ©ment aux schĂ©mas proposĂ©s dans la littĂ©rature d'Ă©volution de ces composĂ©s. La greigite est intĂ©ressante Ă  considĂ©rer. Seule phase dĂ©tectĂ©e quel que soit l’ñge, elle peut s’avĂ©rer un bon marqueur de la biocorrosion du fer dans les assemblages bois-fer

    Plant Extracellular Vesicles and Nanovesicles: Focus on Secondary Metabolites, Proteins and Lipids with Perspectives on Their Potential and Sources

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    While human extracellular vesicles (EVs) have attracted a big deal of interest and have been extensively characterized over the last years, plant-derived EVs and nanovesicles have earned less attention and have remained poorly investigated. Although a series of investigations already revealed promising beneficial health effects and drug delivery properties, adequate (pre)clinical studies are rare. This fact might be caused by a lack of sources with appropriate qualities. Our study introduces plant cell suspension culture as a new and well controllable source for plant EVs. Plant cells, cultured in vitro, release EVs into the growth medium which could be harvested for pharmaceutical applications. In this investigation we characterized EVs and nanovesicles from distinct sources. Our findings regarding secondary metabolites indicate that these might not be packaged into EVs in an active manner but enriched in the membrane when lipophilic enough, since apparently lipophilic compounds were associated with nanovesicles while more hydrophilic structures were not consistently found. In addition, protein identification revealed a possible explanation for the mechanism of EV cell wall passage in plants, since cell wall hydrolases like 1,3-ÎČ-glucosidases, pectinesterases, polygalacturonases, ÎČ-galactosidases and ÎČ-xylosidase/α-L-arabinofuranosidase 2-like are present in plant EVs and nanovesicles which might facilitate cell wall transition. Further on, the identified proteins indicate that plant cells secrete EVs using similar mechanisms as animal cells to release exosomes and microvesicles
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