165 research outputs found

    ABCD2, ABCD2-I, and OTTAWA scores for stroke risk assessment: a direct retrospective comparison

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    Transient ischemic attack (TIA) is a neurologic emergency characterized by cerebral ischemia eliciting a temporary focal neurological deficit. Many clinical prediction scores have been proposed to assess the risk of stroke after TIA; however, studies on their clinical validity and comparisons among them are scarce. The objective is to compare the accuracy of ABCD2, ABCD2-I, and OTTAWA scores in the prediction of a stroke at 7, 90 days, and 1 year in patients presenting with TIA. Single-centre, retrospective study including patients with TIA admitted to the Emergency Department of our third-level, University Hospital, between 2018 and 2019. Five hundred three patients were included. Thirty-nine (7.7%) had a stroke within 1 year from the TIA: 9 (1.7%) and 24 (4.7%) within 7 and 90 days, respectively. ABCD2, ABCD2-I, and OTTAWA scores were significantly higher in patients who developed a stroke. AUROCs ranged from 0.66 to 0.75, without statistically significant differences at each time-point. Considering the best cut-off of each score, only ABCD2 > 3 showed a sensitivity of 100% only in the prediction of stroke within 7 days. Among clinical items of each score, duration of symptoms, previous TIA, hemiparesis, speech disturbance, gait disturbance, previous cerebral ischemic lesions, and known carotid artery disease were independent predictors of stroke. Clinical scores have moderate prognostic accuracy for stroke after TIA. Considering the independent predictors for stroke, our study indicates the need to continue research and prompts the development of new tools on predictive scores for TIA

    Membrane-binding peptides for extracellular vesicles on-chip analysis

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    Small extracellular vesicles (sEVs) present fairly distinctive lipid membrane features in the extracellular environment. These include high curvature, lipid-packing defects and a relative abundance in lipids such as phosphatidylserine and ceramide. sEV membrane could be then considered as a "universal" marker, alternative or complementary to traditional, characteristic, surface-associated proteins. Here, we introduce the use of membrane-sensing peptides as new, highly efficient ligands to directly integrate sEV capturing and analysis on a microarray platform. Samples were analysed by label-free, single-particle counting and sizing, and by fluorescence co-localisation immune staining with fluorescent anti-CD9/anti-CD63/anti-CD81 antibodies. Peptides performed as selective yet general sEV baits and showed a binding capacity higher than anti-tetraspanins antibodies. Insights into surface chemistry for optimal peptide performances are also discussed, as capturing efficiency is strictly bound to probes surface orientation effects. We anticipate that this new class of ligands, also due to the versatility and limited costs of synthetic peptides, may greatly enrich the molecular toolbox for EV analysis

    Detectors for the James Webb Space Telescope Near-Infrared Spectrograph I: Readout Mode, Noise Model, and Calibration Considerations

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    We describe how the James Webb Space Telescope (JWST) Near-Infrared Spectrograph's (NIRSpec's) detectors will be read out, and present a model of how noise scales with the number of multiple non-destructive reads sampling-up-the-ramp. We believe that this noise model, which is validated using real and simulated test data, is applicable to most astronomical near-infrared instruments. We describe some non-ideal behaviors that have been observed in engineering grade NIRSpec detectors, and demonstrate that they are unlikely to affect NIRSpec sensitivity, operations, or calibration. These include a HAWAII-2RG reset anomaly and random telegraph noise (RTN). Using real test data, we show that the reset anomaly is: (1) very nearly noiseless and (2) can be easily calibrated out. Likewise, we show that large-amplitude RTN affects only a small and fixed population of pixels. It can therefore be tracked using standard pixel operability maps.Comment: 55 pages, 10 figure

    Características químicas de um latossolo sob diferentes sistemas de produção no noroeste paulista.

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    Sistemas de manejo conservacionistas que tĂȘm o intuito de evitar o desgaste ou a degradação do solo vĂȘm sendo difundidos na agricultura. Este trabalho teve por objetivo avaliar as caracterĂ­sticas quĂ­micas de um Latossolo sob sistema plantio direto, integração lavoura-pecuĂĄria e integração lavourapecuĂĄria- silvicultura, comparados a uma ĂĄrea de cerrado nativo, em Votuporanga, SP. Conclui-se que os sistemas de produção avaliados apresentaram, na fase inicial de implantação, caracterĂ­sticas quĂ­micas desfavorĂĄveis ao desenvolvimento das culturas, com baixos teores de fĂłsforo e acidez elevada, semelhante a ĂĄrea de cerrado nativo, sendo necessĂĄrio a continuidade dos estudos por um perĂ­odo maior

    Preliminary Integrated Chronostratigraphy of the AND-2A Core, ANDRILL Southern McMurdo Sound Project, Antarctica

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    We use all available chronostratigraphic constraints – biostratigraphy, magnetostratigraphy, radioisotopic dates, strontium-isotope stratigraphy, and correlation of compositional and physical properties to well-dated global or regional records – to construct a preliminary age model for ANDRILL SMS Project’s AND-2A drillcore (77°45.488’S, 165°16.605’E, 383.57 m water depth). These diverse chronostratigraphic constraints are consistent with each other and are distributed throughout the 1138.54 m-thick section, resulting in a well-constrained age model. The sedimentary succession comprises a thick early and middle Miocene section below 224.82 mbsf and a condensed middle/late Miocene to Recent section above this. The youngest sediments are Brunhes age (<0.781 Ma), as confirmed by a radioisotopic age of 0.691±0.049 Ma at 10.23 mbsf and the occurrence of sediments that have normal magnetic polarity down to ~31.1 mbsf, which is interpreted to be the Brunhes/Matuyama reversal (0.781 Ma). The upper section is punctuated by disconformities resulting from both discontinuous deposition and periods of extensive erosion typical of sedimentary environments at the margin of a dynamic ice sheet. Additional breaks in the section may be due to the influence of tectonic processes. The age model incorporates several major hiatuses but their precise depths are still somewhat uncertain, as there are a large number of erosional surfaces identified within the stratigraphic section. One or more hiatuses, which represent a total 7 to 8 million years of time missing from the sedimentary record, occur between about 50 mbsf and the base of Lithostratigraphic Unit (LSU) 3 at 122.86 mbsf. Similarly, between about 145 mbsf and the base of LSU 4 at 224.82 mbsf, one or more hiatuses occur on which another 2 to 3 million years of the sedimentary record is missing. Support for the presence of these hiatuses comes from a diatom assemblage that constrains the age of the core from 44 to 50 mbsf to 2.06-2.84 Ma, two radioisotopic dates (11.4 Ma) and a Sr‑isotope date (11.7 Ma) that indicate the interval from 127 to 145 mbsf was deposited between 11.4 and 11.7 Ma, and three diatom occurrence datums from between 225.38 and 278.55 mbsf that constrain the age of this upper part of Lithostratigraphic Unit (LSU) 5 to 14.29 - 15.89 Ma. Below the boundary between LSU 5 and 6 sedimentation was relatively continuous and rapid and the age model is well-constrained by 9 diatom datums, seven 40Ar-39Ar dates, one Sr-isotope date, and 19 magnetozones. Even so, short hiatuses (less than a few hundred thousand years) undoubtedly occur but are beyond the resolution of current chronostratigraphic age constraints. Diatom first and last occurrence datums provide particularly good age control from the top of LSU 6 down to 771.5 mbsf (in LSU 10), where the First Occurrence (FO) of Thalassiosira praefraga (18.85 Ma) is observed. The diatom datum ages are supported by radioisotopic dates of 17.30±0.31 Ma at 640.14 mbsf (in LSU 9) and 18.15±0.35 and 17.93±0.40 Ma for samples from 709.15 and 709.18 mbsf (in LSU 10), respectively, and 18.71±0.33 Ma for a sample from 831.67 mbsf (in LSU 11). The sediments from 783.69 mbsf to the base of the hole comprise two thick normal polarity magnetozones that bound a thinner reversed polarity magnetozone (958.59 - 985.64 mbsf). This polarity sequence most likely encompasses Chrons C5En, C5Er, and C6n (18.056 - 19.772 Ma or slightly older given uncertainties in this section of the geomagnetic polarity timescale), but could be also be Chrons C6n, C6r, and C6An.1n (18.748 - 20.213 Ma). Either polarity sequence is compatible with the 40Ar–39Ar age of 20.01±0.35 Ma obtained from single-grain analyses of alkali feldspar from a tephra sample from a depth of 1093.02 mbsf, although the younger interpretation allows a better fit with chronostratigraphic data up-core. Given this age model, the mean sedimentation rate is about 18 cm/k.y. from the top of LSU 6 to the base of the hole.Published221-2202.2. Laboratorio di paleomagnetismoN/A or not JCRreserve

    Central nervous system and muscular bundles preserved in a 240 million year old giant bristletail (Archaeognatha: Machilidae)

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    Among the incomparably diverse group of insects no cases of central nervous system (CNS) preservation have been so far described in compression fossils. A third of the fossil insects collected from a 240-239 million year old (Ma) level at Monte San Giorgio UNESCO World Heritage (SwitzerlandItaly) underwent phosphatization, resulting in the extraordinary preservation of soft tissues. Here we describe Gigamachilis triassicus gen. et sp. nov. (Archaeognatha: Machiloidea: Machilidae) that, with an estimated total length of similar to 80 millimeters, represents the largest apterygote insect ever recorded. The holotype preserves: (i) components of the CNS represented by four abdominal ganglia, optic lobes with neuropils and compound retina;(ii) muscular bundles. Moreover, G. triassicus, possessing morphological features that prompt its assignment to the extant archaeognathan ingroup Machilidae, places the origin of modern lineages to Middle Triassic. Interestingly, at Monte San Giorgio, in the same stratigraphic unit the modern morphology of G. triassicus co-occurs with the ancient one represented by Dasyleptus triassicus (Archaeognatha: dagger Monura). Comparing these two types of body organization we provide a new reconstruction of the possible character evolution leading towards modern archaeognathan forms, suggesting the acquisition of novel features in a lineage of apterygote insects during the Permian or the Lower Triassic

    The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope: I. Overview of the instrument and its capabilities

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    We provide an overview of the design and capabilities of the near-infrared spectrograph (NIRSpec) onboard the James Webb Space Telescope. NIRSpec is designed to be capable of carrying out low-resolution (R ⁣=30 ⁣−330R\!=30\!-330) prism spectroscopy over the wavelength range 0.6−5.3â€‰âŁÂ ÎŒ0.6-5.3\!~\mum and higher resolution (R ⁣=500 ⁣−1340R\!=500\!-1340 or R ⁣=1320 ⁣−3600R\!=1320\!-3600) grating spectroscopy over 0.7−5.2â€‰âŁÂ ÎŒ0.7-5.2\!~\mum, both in single-object mode employing any one of five fixed slits, or a 3.1×\times3.2 arcsec2^2 integral field unit, or in multiobject mode employing a novel programmable micro-shutter device covering a 3.6×\times3.4~arcmin2^2 field of view. The all-reflective optical chain of NIRSpec and the performance of its different components are described, and some of the trade-offs made in designing the instrument are touched upon. The faint-end spectrophotometric sensitivity expected of NIRSpec, as well as its dependency on the energetic particle environment that its two detector arrays are likely to be subjected to in orbit are also discussed

    The James Webb Space Telescope Mission

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    Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4m4m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5m6.5m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure
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