This article is the result of doctoral research in landscape architecture. It seeks to decipher the lexical, conceptual and operational developments relating to new configurations linking the urban ...tissue and agricultural production in urban centres. The first part of the article redefines the context and the issues regarding synergies between the city and agriculture. The second part presents a lexical study of the two emerging concepts of agri-urbanism and agricultural urbanism explaining how these notions contribute to redefining the role of agriculture as a planning tool in urban centres. Their operational and spatial translation is then studied in a series of projects, mainly in the Ile-de-France region, revealing a wide variety of approaches and landscapes. The implementation of such food-producing projects raises several questions about the need to combine urban and agricultural planning tools and to invent new professional practices for negotiating, designing and taking action. From this perspective, the strengthening of approaches in landscape architecture opens up new prospects for federating actors, developing joint projects and thus promoting complementarity between urban and agricultural spaces.
Cet article est issu d’une recherche doctorale par le projet de paysage. Il propose de décrypter des évolutions d’ordre lexical, conceptuel et opérationnel, relatives à de nouvelles configurations ...entre fabrique urbaine et production agricole dans les métropoles. Une première partie resitue le contexte et les enjeux de synergies ville-agriculture. Puis une enquête lexicale portant notamment sur agriurbanisme et urbanisme agricole, deux concepts émergents, explicite en quoi ils contribuent à redéfinir dans les discours le rôle de l’agriculture comme outil d’aménagement des métropoles. Ensuite leur traduction opérationnelle et spatiale est étudiée via un panel de projets principalement franciliens, qui révèlent une diversité d’approches et de paysages. La mise en œuvre de tels projets nourriciers révèle plusieurs enjeux, notamment la nécessité de combiner des outils d’aménagement urbains et agricoles, et d’inventer de nouvelles pratiques professionnelles pour négocier, concevoir et agir. Dans cette dynamique, le renforcement de la pensée et de l’action paysagistes ouvre des pistes pour fédérer les acteurs, élaborer des projets en commun et ainsi favoriser des complémentarités entre espaces urbanisés et agricoles.
Purpose
The objective of our study was to evaluate the ability of preoperative MRI tractography to visualize and predict the path of the facial nerve with respect to an intra-parotid mass.
Methods
We ...performed an observational bicentric study from June 2019 to August 2020. All patients older than 18 years old, treated for a parotid mass with surgical indication, without MRI contraindication and who agreed to participate in the study were enrolled prospectively. All patients underwent a cervico-facial MRI with tractographic analysis. Postprocessed tractography images of the intra-parotid facial nerve were analyzed by two expert radiologists in head and neck imaging. The intraoperative anatomical description of the facial nerve path and its relationship to the mass was performed by the surgeon during the operation, with no visibility on MRI examination results. A statistical study allowed for the description of the data collected as well as the measurement of inter-observer agreement and agreement between tractography and surgery using kappa coefficients.
Results
Fifty-two patients were included. The facial nerve trunk and its first two divisional branches were visualized via tractography in 93.5% of cases (
n
= 43). The upper distal branches were visualized in 51.1% of cases (
n
= 23), and the lower branches were visualized in 73.3% of cases (
n
= 33). Agreement with the location described per-operatively was on average 82.9% for the trunk, 74.15% for the temporal branch, and 75.21% for the cervico-facial branch.
Conclusion
Fiber tractography analysis by MRI of the intra-parotid facial nerve appears to be a good test for predicting the path of the nerve over the parotid mass and could be an additional tool to guide the surgeon in the operative procedure.
Various perturbation approaches have been proposed for representing model error in convection-permitting ensemble prediction. Their evaluation usually relies on time-averaged ensemble prediction ...statistics and on complex case studies. In this work, their detailed physical behaviour is studied in order to understand their differences, and to help their optimization. A process-level intercomparison framework is used to investigate the widely used SPPT (stochastic perturbations of physics tendencies), independent SPPT, and random-parameters model-perturbation approaches. Ensemble predictions with the single-column version of the Arome numerical-weather-prediction model are evaluated on three different boundary-layer regimes: cumulus convection, stratocumulus-topped boundary layer, and radiation fog. The independent SPPT approach is found to produce more dispersion than the SPPT approach, particularly when several physics parametrizations are in near equilibrium. It also appears to be more numerically stable near the surface. The random parameters approach perturbations are structurally very different from the other approaches, particularly regarding cloud structure. The independent SPPT and random parameters approaches have very different sensitivities to the atmospheric conditions, which suggests that intercomparisons of ensemble-model-error approaches should carefully account for situation dependency. Substantial forecast biases are produced by random parameters with respect to the unperturbed model. These results suggest that the independent SPPT approach can bring major improvements over the SPPT approach with minimal effort, that there is some complementarity between the independent SPPT and random parameters approaches, but that implementing random-parameters-type approaches in operational applications may require careful tuning to avoid creating forecast biases.
The determination of seven arsenic species in seafood was performed using ion exchange chromatography on an IonPac AS7 column with inductively coupled plasma mass spectrometry detection after ...microwave assisted extraction. The effect of five parameters on arsenic extraction recoveries was evaluated in certified reference materials. The recoveries of total arsenic and of arsenic species with the two best extraction media (100% H
2O and 80% aqueous MeOH) were generally similar in the five seafood certified reference materials considered. However, because MeOH co-elutes with arsenite, which would result in a positively biased arsenite concentration, the 100% H
2O extraction conditions were selected for validation of the method. Figures of merit (linearity, LOQs (0.019–0.075
mg As
kg
−1), specificity, trueness (with recoveries between 82% (As(III)) and 104% (As(V) based on spikes or certified concentrations), repeatability (3–14%), and intermediate precision reproducibility (9–16%) of the proposed method were satisfactory for the determination of arsenite, monomethylarsonic acid, dimethylarsinic acid, arsenate, arsenobetaine and arsenocholine in fish and shellfish. The performance criteria for trimethylarsine oxide, however, were less satisfactory. The method was then applied to 65 different seafood samples. Arsenobetaine was the main species in all samples. The percentage of inorganic arsenic varied between 0.4–15.8% in shellfish and 0.5–1.9% at the utmost in fish. The main advantage of this method that uses only H
2O as an extractant and nitric acid as gradient eluent is its great compatibility with the long-term stability of both IEC separation and ICP-MS detection.
This study presents the development, validation and application of a new analytical approach for the simultaneous speciation analysis of Cr(III) and Cr(VI) in meat and dairy products by ...high-performance liquid chromatography (HPLC) coupled to inductively coupled plasma mass spectrometry (ICP-MS) and double spike species specific-isotope dilution (SS-ID). The species extraction was achieved by sequential complexation of Cr(III) with ethylenediaminetetraacetic acid (EDTA) and of Cr(VI) with 1,5-diphenylcarbazide (DPC) in the same analytical run. The HPLC separation of complexed species was carried out using a short (5 cm) microbore anion-exchange HPLC column and a mobile phase consisting of 0.01 mol L−1 HNO3 + 2.5% (v/v) MeOH + 0.30 mol L−1 EDTA (pH = 2) in isocratic elution mode with excellent baseline separation achieved in less than 3 min. The method was validated by means of the accuracy profile approach by carrying out 6 measurement series in duplicate on (six) different days over a timespan of two months. The quantification limit was 0.013 μg kg−1 for Cr(III) and 0.049 μg kg−1 for Cr(VI), respectively. The measurement bias corresponding to the validity domain ranged from 0.01 to 0.11%, whereas the coefficient of variation in terms of repeatability (CVr) varied from 2.9 to 11.6% (depending on the analyte level) for Cr(III) and from 6.7 to 11.8% for Cr(VI). Similarly, the coefficient of variation in terms of intermediate reproducibility (CVR) ranged from 6.8 to 13% for Cr(III) and from 6.8 to 25.9% for Cr(VI), respectively. The method was successfully applied to the analysis of a selection of food samples such as baby and semi-skimmed milk and steak beef samples. Cr(VI) was not quantified in any of these samples while Cr(III) levels ranged between 2.7 and 4.7 μg kg−1, which were comparable with the levels of total chromium analysed in the same samples by ICP-MS (accredited method). The method presented here with combined use of species specific isotope dilution and sequential species complexation is a powerful analytical tool for accurate and precise quantification of Cr(III) and Cr(VI) at trace levels and allows for correction of any species interconversion during sample preparation.
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•New analytical approach for simultaneous speciation analysis of Cr(III)-Cr(VI) in food by HPLC-ICP-MS and double spike SS-ID.•Single run selective complexation/derivatisation of Cr(III) and Cr(VI) by EDTA and 1,5-diphenylcarbazide, respectively.•The method was validated by means of the accuracy profile, one of the most robust approaches for this purpose.•Cr(VI) was not quantified in the milk/beef samples analysed here whereas Cr(III) levels were highly comparable with total Cr.
Levels of 14 trace elements (Al, Ti, V, Cr, Mn, Co, Ni, Zn, As, Se, Cd, Sn, Hg, and Pb) and 5 arsenic species (arsenite/As(III), arsenate/As(V), monomethylarsonic acid/MA, dimethylarsinic acid/DMA, ...and arsenobetaine/AsB) were assessed in the gonads of sea urchin samples (
Paracentrotus lividus
) from North-West Mediterranean Sea (French coast). The samples were collected from 13 sites characterized by different types and levels of chemical contamination. Trace elements levels were measured by inductively coupled plasma-mass spectrometry (ICP-MS) following microwave (acid) digestion in a closed system, whereas As speciation analysis was carried out by ion-exchange liquid chromatography coupled with ICP-MS after microwave-assisted extraction. High levels of trace elements were found in sea urchins sampled from Corsica whereas the samples from Théoule were found to be the least contaminated. From all the analyzed urchin samples, none showed Cd, Hg, or Pb concentrations above the regulatory levels set by the European Community (EC) No. 1881/2006 for seafood or bivalve mollusks. Regarding arsenic speciation, AsB was confirmed to be the predominant species. Inorganic As (As(III) + As(V)) was mainly constituted by As(III), which was quantified in all samples. Methylated As forms (MA and DMA) represent 9 to 23% of the total As.
We aimed to determine whether high-flow nasal oxygen could reduce the incidence of decreased peripheral oxygen saturation (SpO2) compared with standard oxygen in patients at risk of hypoxaemia ...undergoing gastrointestinal endoscopy under deep sedation.
This was a multicentre, randomised controlled trial with blinded assessment of the primary outcome evaluating high-flow nasal oxygen (gas flow 70 L min−1, inspired oxygen fraction 0.50) or standard oxygen delivered via nasal cannula or face mask (6 L min−1) or nasopharyngeal tube (5 L min−1) in patients at risk of hypoxaemia (i.e. >60 yr old, or with underlying cardiac or respiratory disease, or with ASA physical status >1, or with obesity or sleep apnoea syndrome) undergoing gastrointestinal endoscopy. The primary endpoint was the incidence of SpO2 ≤92%. Secondary outcomes included prolonged or severe desaturations, need for manoeuvres to maintain free upper airways, and other adverse events.
In 379 patients, a decrease in SpO2 ≤92% occurred in 9.4% (18/191) for the high-flow nasal oxygen group, and 33.5% (63/188) for the standard oxygen groups (adjusted absolute risk difference, –23.4% 95% confidence interval (CI), –28.9 to –16.7; P<0.001). Prolonged desaturation (>1 min) and manoeuvres to maintain free upper airways were less frequent in the high-flow nasal oxygen group than in the standard oxygen group (7.3% vs 14.9%, P=.02, and 11.1% vs 32.4%, P<0.001).
In patients at risk of hypoxaemia undergoing gastrointestinal endoscopy under deep sedation, use of high-flow nasal oxygen significantly reduced the incidence of peripheral oxygen desaturation.
NCT03829293.
The genome folds into a hierarchy of three-dimensional structures within the nucleus. At the sub-megabase scale, chromosomes form topologically associating domains (TADs)
. However, how TADs fold in ...single cells is elusive. Here, we reveal TAD features inaccessible to cell population analysis by using super-resolution microscopy. TAD structures and physical insulation associated with their borders are variable between individual cells, yet chromatin intermingling is enriched within TADs compared to adjacent TADs in most cells. The spatial segregation of TADs is further exacerbated during cell differentiation. Favored interactions within TADs are regulated by cohesin and CTCF through distinct mechanisms: cohesin generates chromatin contacts and intermingling while CTCF prevents inter-TAD contacts. Furthermore, TADs are subdivided into discrete nanodomains, which persist in cells depleted of CTCF or cohesin, whereas disruption of nucleosome contacts alters their structural organization. Altogether, these results provide a physical basis for the folding of individual chromosomes at the nanoscale.
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