1,282 research outputs found

    Effective Visual Communication and Problematic Practices: The Case of the National Science Foundation’s Visualization Challenge

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    The role that images can play in communicating science to non-experts is contingent on the rhetorical choices of the organizations using them as tools for public outreach. The National Science Foundation’s annual visualization competition illuminates the potential pitfalls of visual science communication and opens up for discussion issues of effectiveness and ethics

    First results on the use of a EDXRF scanner for 3D imaging of paintings

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    A 3D map of chemical elements distribution from energy-dispersive X-ray fluorescence (EDXRF) analysis would be a perfect conclusion in a detailed study of any type of artifact. This map can be easily achieved by using synchrotron light as source of radiation, and microoptics both at the source and at the detector. In such a manner a micro-voxel is irradiated and detected, which can be at any depth with respect to the surface of the artifact. This method is effective but needs a high-intensity X-ray source; therefore, its use in archaeometry is limited. An alternative method is proposed in the present paper, which uses a portable EDXRF-device to measure the altered Kα/KÎČ or Lα/LÎČ-ratios, which allow to locate the chemical elements. Several examples are described

    Three-body bound states with zero-range interaction in the Bethe-Salpeter approach

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    The Bethe-Salpeter equation for three bosons with zero-range interaction is solved for the first time. For comparison the light-front equation is also solved. The input is the two-body scattering length and the outputs are the three-body binding energies, Bethe-Salpeter amplitudes and light-front wave functions. Three different regimes are analyzed: ({\it i}) For weak enough two-body interaction the three-body system is unbound. ({\it ii}) For stronger two-body interaction a three-body bound state appears. It provides an interesting example of a deeply bound Borromean system. ({\it iii}) For even stronger two-body interaction this state becomes unphysical with a negative mass squared. However, another physical (excited) state appears, found previously in light-front calculations. The Bethe-Salpeter approach implicitly incorporates three-body forces of relativistic origin, which are attractive and increase the binding energy.Comment: 13 pages, 7 figure

    Bound state structure and electromagnetic form factor beyond the ladder approximation

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    We investigate the response of the bound state structure of a two-boson system, within a Yukawa model with a scalar boson exchange, to the inclusion of the cross-ladder contribution to the ladder kernel of the Bethe-Salpeter equation. The equation is solved by means of the Nakanishi integral representation and light-front projection. The valence light-front wave function and the elastic electromagnetic form factor beyond the impulse approximation, with the inclusion of the two-body current, generated by the cross-ladder kernel, are computed. The valence wave function and electromagnetic form factor, considering both ladder and ladder plus cross-ladder kernels, are studied in detail. Their asymptotic forms are found to be quite independent of the inclusion of the cross-ladder kernel, for a given binding energy. The asymptotic decrease of form factor agrees with the counting rules. This analysis can be generalized to fermionic systems, with a wide application in the study of the meson structure.Comment: 19 pages, 6 figures, submitted to Phys. Lett.

    A cerebral bridge from olfactory cognition to spatial navigation

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    An evolutionary paradox is the variability of the olfactory bulb size, in contrast to the other brain regions, which are sized proportionally to the peripheral function. This variability seems to be the result of selection for the olfactory function. This disagreement may derive from considering smell as a sense linked to odorous discrimination. In many vertebrates and in terrestrial and marine mammals, the sense of smell has evolved into functions related to the eco-localization. So, if the olfactory function involves spatial perception and navigation, this, couldexplain the proportional discrepancy between the olfactory bulb and olfactory cortex. Humans are able to discriminate a spatial position as a function of olfactory cues. Vice versa, in neurodegenerative syndromes the orientation capacity and olfactory perception are impaired. This leads us to think that could be a common cross-modal processing, of phylogenetic origin, which links olfactory perception and spatial orientation. Starting from these theoretical assumptions, we conducted a basic research, on 100 healthy subjects, investigating, through both behavioral and electroencephalographic data, the connection between spatial memory span and olfactory spatial memory span. Subjects were assessed through a three-condition task: normal Corsi Block Test (CBT), ‘Olfactory’ Block Test (OBT) and a ‘Semantic-Olfactory’ Block Test (SOBT). CBT consisted in a test on spatial memory span; OBT consisted in a presentation a spatial sequences of 9 different odorants (i.e., Eucalyptol, Carvone, Eugenol, Isoamyl Acetate, Geraniol, Phenethyl Alcohol, Acetophenone, Cinnamon, Hexanal) instilled on paper square not recognizable by any sign, positioned on a CBT, and showed in a spatial navigation way, and SOBT consisted of a semantic labelled of olfactory spatial navigation. A GLM repeated measure highlighted significant differences during the three conditions. Subjects had different SPANs due to different conditions. The Semantic olfactory memory SPAN was inferior respect Olfactory span and Spatial Span. Furthermore was found a significant positive correlation between the three condition. The 5 subjects with higher SPAN scores, 5 with medium scores and the 5 subjects with lower SPAN scores were recruited to investigate ERP components elicited during the cross-modal task. Subjects had to perform, during a high-density EEG recording, an olfactory task (administered through the device US2017127971 (A1) “? 2017-05-11), an EEG Posner spatial cueing task and a go/no-go olfactory semantic categorization task. The results of this study will be discussed in light of a theoretical connection between these three aspects of cortical functions that seem strongly interconnected

    Gold and Silver joining technologies in the Moche Tombs “Señor de SipĂĄn” and “Señora de Cao jewelery

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    About 200 gold and silver funerary ornaments from the Moche tombs “Señor de SipĂĄn” and “Señora de Cao” were analyzed to determine their metallurgic characteristics. Of particular interest was the question about the gold-silver joining process. To this aim, following methods were employed, all based on the use of X-rays: - energy dispersive X-ray fluorescence; - transmission of monoenergetic fluorescent X-rays; - radiography. At least three joining methods were possibly identified: - of gluing gold and silver sheets; - of brazing using a proper solder; - of using a mercury amalgam

    Chromosome 1p13 genetic variants antagonize the risk of myocardial infarction associated with high ApoB serum levels

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    PMCID: PMC3480949This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    Pharmacological effects of raas blockade in ischemic nephropathy

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    Background: The management of ischemic nephropathy due to atherosclerotic renal artery stenosis has become increasingly conservative in the modern era, with current guidelines recommending optimized medical therapy as the initial step. The doubts raised by the recently published trials of revascularization strategies have led to a renewed focus on pharmacological strategies promoting blood pressure control and renal protection. It is essential to further elucidate the pathophysiological mechanisms underlying hypoperfusion induced renal microvascular dysfunction with subsequent tissue injury and fibrogenesis. The role of renin angiotensin aldosterone system as a mediator of the main pathophysiological consequences of ischemic nephropathy is well known. However, more recent experimental evidence on the adrenergic system and intrarenal tubular feedback mechanisms has stimulated new interest towards a multi-target therapeutic approach. Methods: This review focuses on the pharmacology of the principle therapeutic drug classes currently used in the treatment of atherosclerotic renal artery stenosis with an analysis of their metabolic aspects and use in clinical practice based on evidence from clinical trials. Results and Conclusions: An optimal pharmacologic approach is crucial for a successful prevention of renal injury and cardiovascular events in this high-risk population. Antihypertensive treatment should include renin angiotensin aldosterone system blockade medication not only for their antihypertensive properties, but especially for those cardio and renoprotectiv

    XISMuS x-ray fluorescence imaging software for multiple samples

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    X-rays have long been used as a non-destructive analytical technique to investigate artefacts and objects that can be considered cultural heritage. With the unceasing development of technologies and miniaturization of electronics, X-ray Fluorescence (XRF) analysis has undergone a natural evolution, being now extensively used in a bi-dimensional manner, scanning whole surfaces and generating astonishing amounts of data. Evaluating all this data demands a software distribution or at least a stand-alone algorithm. The former being an obvious choice, as software are easy to install and the learning curve is fast. Moreover, developing a proprietary algorithm is time consuming and not always needed for the average user. In this scope, XIMuS was developed as an ad hoc software for macro-XRF analysis (MA-XRF), with an intuitive and simple graphical user interface (GUI). The software provides several built-in tools, staple for the interpretation of X-ray fluorescence data, automated data evaluation and some novelty functionalities as data stitching. XISMuS creates an iterative user database as samples are loaded and compiled through usage, facilitating navigation through different datasets. Simultaneous samples can be loaded in separate instances for comparison purposes. Elemental mapping is made simple, the methods available are described and have each one an application for fast, balanced or precise calculations, supporting parallel computing. Ratios between elements in specific regions of the image can be measured while a region-derived spectrum is shown and updated live. Image correlation can be performed supporting the usage of threshold filters and/or region selection. Batch exporting is also available, cross-normalizing the input datasets
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