607 research outputs found

    Variations spatiales et temporelles des précipitations des neuf division climatiques de l'Oklahoma et implications pour l'utilisation locale de l'indice régional

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    L'objectif de cette Ă©tude est de quantifier l'importance des variations spatiales des prĂ©cipitations mensuelles par rapport Ă  leurs variations temporelles rĂ©gionales Ă  l'Ă©chelle des divisions climatiques de l'Oklahoma. Les variations des prĂ©cipitations Ă  l'intĂ©rieur d'une division climatique sont supposĂ©es ĂȘtre constituĂ©es par trois composantes : les variations spatiales systĂ©matiques, les variations temporelles moyennes de la division climatique et les variations alĂ©atoires. Les variations spatiales systĂ©matiques sont dĂ©finies par le gradient des prĂ©cipitations moyennes sur l'intĂ©gralitĂ© de la pĂ©riode. Les variations temporelles moyennes de la division climatique sont reprĂ©sentĂ©es par les variations temporelles de la moyenne spatiale des prĂ©cipitations observĂ©es aux stations de la division, cette moyenne Ă©tant appelĂ©e indice rĂ©gional. Les variations alĂ©atoires sont estimĂ©es avec les diffĂ©rences entre les valeurs centrĂ©es rĂ©duites des prĂ©cipitations observĂ©es aux stations et celles de l'indice rĂ©gional. Cette Ă©tude montre que les amplitudes des variations alĂ©atoires des prĂ©cipitations mensuelles des neuf divisions climatiques de l'Oklahoma sont significatives par rapport aux variations temporelles rĂ©gionales. La quantification de l'amplitude des variations alĂ©atoires est importante pour l'utilisation des prĂ©visions rĂ©gionales des prĂ©cipitations, car elle permet de dĂ©terminer les plages de variation des prĂ©cipitations locales autour de l'indice rĂ©gional et donc l'augmentation des risques pris par les utilisateurs des prĂ©visions rĂ©gionales pour des applications locales.The objective of this study is to quantify the magnitude of the spatial variations of the monthly precipitation and relate them to the regional temporal variations of the monthly precipitation at the spatial scale of the climate division of Oklahoma. The precipitation variations within a climate division are assumed to consist of three components: the systematic spatial variations, the mean temporal variations of the climate division, and random variations. The systematic spatial variations are defined with the long-term precipitation gradient. The mean temporal variations of the climate division are represented by the temporal variations of the spatial average of the precipitation observed at the stations included in the climate division; this average is called divisional precipitation. The random variations are estimated with the differences between the standardized values of station and divisional precipitation. This study shows that the magnitude of the random variations of the monthly precipitation of the nine climate divisions of Oklahoma is significant compared to the regional temporal variations. The quantification of the magnitude of the random variations is critical for the use of regional precipitation forecasts, because it allows one to define ranges of local precipitation around the divisional precipitation, and then to quantify the increase of the risk taken by local users of the regional precipitation forecasts

    Analyse et amĂ©lioration d'un indice pluviomĂ©trique mensuel rĂ©gional pour les grandes plaines du sud des États-Unis

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    L'indice pluviomĂ©trique mensuel proposĂ© par le National Climatic Data Center (NCDC) est Ă©gal Ă  la moyenne arithmĂ©tique des prĂ©cipitations observĂ©es Ă  certaines stations de la division climatique. Les diffĂ©rents problĂšmes d'homogĂ©nĂ©itĂ© des donnĂ©es prises en compte par le NCDC pour le calcul de l'indice sont quantifiĂ©s pour la rĂ©gion climatique centrale de l'Oklahoma. Une amĂ©lioration de la mĂ©thode de calcul est proposĂ©e. Le calcul de ce nouvel indice utilise un nombre fixe de stations et fait appel Ă  une mĂ©thode d'estimation des donnĂ©es manquantes. L'estimation des valeurs manquantes permet de disposer d'un jeu de donnĂ©es complet, ce qui augmente la reprĂ©sentativitĂ© de l'indice. Les moyennes mensuelles des valeurs absolues des diffĂ©rences entre l'indice NCDC et l'indice proposĂ© sont comprises entre 6 % (mai) et 13 % (aoĂ»t) des prĂ©cipitations moyennes et entre 9 % (novembre) et 24 % (aoĂ»t) des Ă©cart-types mensuels. Ces valeurs dĂ©montrent que les problĂšmes liĂ©s Ă  la mĂ©thode de calcul d'un indice pluviomĂ©trique mensuel rĂ©gional utilisĂ©e par le NCDC peuvent ĂȘtre importants. Les rĂ©sultats de recherches sur la variabilitĂ© temporelle des prĂ©cipitations utilisant un indice pluviomĂ©trique rĂ©gional devraient ĂȘtre interprĂ©tĂ©s en connaissance de ces diffĂ©rences.The NCDC monthly precipitation index is computed as a simple average of the monthly precipitation at several stations within a climate division. The influences of the discontinuities in records used by NCDC are quantified for the central climate division of Oklahoma. An improvement of the calculation method is proposed. The number of stations used is fixed and the missing monthly data values are filled. The monthly averages of the absolute values of the differences between the two indices vary from 6 % (May) to 13 % (August) of the mean monthly precipitation and from 9 % (November) to 24 % (August) of their mean temporal variations. These values demonstrate that the discontinuities in station records of the NCDC divisional precipitation index can be relevant and that research results on regional precipitation variability should be interpreted with consideration of the approximation errors introduced

    The horizontal gene transfer of Agrobacterium T-DNAs into the series Batatas (genus Ipomoea) genome is not confined to hexaploid sweetpotato

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    The discovery of the insertion of IbT-DNA1 and IbT-DNA2 into the cultivated (hexaploid) sweetpotato [Ipomoea batatas (L.) Lam.] genome constitutes a clear example of an ancient event of Horizontal Gene Transfer (HGT). However, it remains unknown whether the acquisition of both IbT-DNAs by the cultivated sweetpotato occurred before or after its speciation. Therefore, this study aims to evaluate the presence of IbT-DNAs in the genomes of sweetpotato's wild relatives belonging to the taxonomic group series Batatas. Both IbT-DNA1 and IbT-DNA2 were found in tetraploid I. batatas (L.) Lam. and had highly similar sequences and at the same locus to those found in the cultivated sweetpotato. Moreover, IbT-DNA1 was also found in I. cordatotriloba and I. tenuissima while IbT-DNA2 was detected in I. trifida. This demonstrates that genome integrated IbT-DNAs are not restricted to the cultivated sweetpotato but are also present in tetraploid I. batatas and other related species

    Identification of High Platelet Reactivity Despite ADP P2Y12 Inhibitor Treatment: Two Populations in the Vasodilator-Stimulated Phosphoprotein Assay and Variable PFA-P2Y Shapes of Curve.

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    Introduction Response to ADP P2Y <sub>12</sub> receptor inhibition by clopidogrel can be evaluated by various techniques. Here, we compared a functional rapid point-of-care technique (PFA-P2Y) with the degree of biochemical inhibition assessed by the VASP/P2Y <sub>12</sub> assay. Methods Platelet response to clopidogrel was investigated in 173 patients undergoing elective intracerebral stenting (derivation cohort n = 117; validation cohort n = 56). High platelet reactivity (HPR) was defined as PFA-P2Y occlusion time <106 seconds or VASP/P2Y <sub>12</sub> platelet reactivity index (PRI) >50%. Results In the derivation cohort, receiver operator characteristics analysis for the ability of PFA-P2Y to detect biochemical HPR showed high specificity (98.4%) but poor sensitivity (20.0%) and a very low area under the curve (0.59). The VASP/P2Y <sub>12</sub> assay revealed two coexisting platelet populations with different levels of vasodilator-stimulated phosphoprotein (VASP) phosphorylation: a fraction of highly phosphorylated, inhibited platelets and another of poorly phosphorylated, reactive platelets. Analysis of the PFA-P2Y curve shape revealed different types, categorized by time of occlusion (<106 seconds, 106 to 300 seconds, >300 seconds), and pattern (regular, irregular, and atypical). Noteworthy, curves with late occlusion and permeable curves with an irregular or atypical pattern correlated with VASP-PRI >50% and smaller sizes of the inhibited platelet subpopulation. Considering the PFA-P2Y shape of the curve for the detection of HPR improved sensitivity (72.7%) and preserved specificity (91.9%), with a rather high AUC (0.823). The validation cohort confirmed the VASP/P2Y <sub>12</sub> assay data and the usefulness of considering the PFA-P2Y curve shape. Conclusion In patients treated with acetylsalicylic acid and clopidogrel for 7-10 days, the VASP/P2Y <sub>12</sub> assay reveals two coexisting subpopulations of differentially inhibited platelets, whose relative sizes predict global PRI and distinct PFA-P2Y curve patterns, indicating incomplete clopidogrel efficacy. The detailed analysis of both VASP/P2Y <sub>12</sub> and PFA-P2Y is necessary for optimal detection of HPR

    Enhancing digital soil mapping in southeastern Brazil: incorporating stream density and soil reflectance from multiple depths.

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    This study proposes a novel and simple method to incorporate laboratory soil spectral data in the production of digital soil maps

    Visually targeted reaching in horse-head grasshoppers

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    Visually targeted reaching to a specific object is a demanding neuronal task requiring the translation of the location of the object from a two-dimensionsal set of retinotopic coordinates to a motor pattern that guides a limb to that point in three-dimensional space. This sensorimotor transformation has been intensively studied in mammals, but was not previously thought to occur in animals with smaller nervous systems such as insects. We studied horse-head grasshoppers (Orthoptera: Proscopididae) crossing gaps and found that visual inputs are sufficient for them to target their forelimbs to a foothold on the opposite side of the gap. High-speed video analysis showed that these reaches were targeted accurately and directly to footholds at different locations within the visual field through changes in forelimb trajectory and body position, and did not involve stereotyped searching movements. The proscopids estimated distant locations using peering to generate motion parallax, a monocular distance cue, but appeared to use binocular visual cues to estimate the distance of nearby footholds. Following occlusion of regions of binocular overlap, the proscopids resorted to peering to target reaches even to nearby locations. Monocular cues were sufficient for accurate targeting of the ipsilateral but not the contralateral forelimb. Thus, proscopids are capable not only of the sensorimotor transformations necessary for visually targeted reaching with their forelimbs but also of flexibly using different visual cues to target reaches. © 2012 The Royal Society

    Measurement of the magnetic field errors on TCV

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    A set of 24 saddle loops is used on the Tokamak Ă  Configuration Variable (TCV) to measure the radial magnetic flux at different toroidal and vertical positions. The new system is calibrated together with the standard magnetic diagnostics on TCV. Based on the results of this calibration, the effective current in the poloidal field coils and their position is computed. These corrections are then used to compute the distribution of the error field inside the vacuum vessel for a typical TCV discharge. Since the saddle loops measure the magnetic flux at different toroidal positions, the non-axisymmetric error field is also estimated and correlated to a shift or a tilt of the poloidal field coils
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