1,700 research outputs found

    Revoque grueso deteriorado por la cristalización de ettringita

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    Se analizó una muestra constituida por el revestimiento, el pegamento adhesivo y parte del revoque grueso de una pared exterior de un edificio de la ciudad de Buenos Aires. Debido a procesos de reacción, se produjeron desprendimientos localizados en el piso 8. Del estudio realizado, surgió claramente que el deterioro se concentraba en el revoque grueso. Al microscopio se observó el desarrollo de un proceso de alteración, dentro del revoque, que dio lugar a la cristalización de ettringita. Esto fue confirmado por DRX. Los estudios morfológicos mediante SEM permitieron observar las formas características de este mineral y confirmar su composición por EDAX

    Nucleon scalar and tensor charges using lattice QCD simulations at the physical value of the pion mass

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    We present results on the light, strange and charm nucleon scalar and tensor charges from lattice QCD, using simulations with Nf=2N_f=2 flavors of twisted mass Clover-improved fermions with a physical value of the pion mass. Both connected and disconnected contributions are included, enabling us to extract the isoscalar, strange and charm charges for the first time directly at the physical point. Furthermore, the renormalization is computed non-perturbatively for both isovector and isoscalar quantities. We investigate excited state effects by analyzing several sink-source time separations and by employing a set of methods to probe ground state dominance. Our final results for the scalar charges are gSu=5.20(42)(15)(12)g_S^u = 5.20(42)(15)(12), gSd=4.27(26)(15)(12)g_S^d = 4.27(26)(15)(12), gSs=0.33(7)(1)(4)g_S^s=0.33(7)(1)(4), gSc=0.062(13)(3)(5)g_S^c=0.062(13)(3)(5) and for the tensor charges gTu=0.782(16)(2)(13)g_T^u = 0.782(16)(2)(13), gTd=0.219(10)(2)(13)g_T^d = -0.219(10)(2)(13), gTs=0.00319(69)(2)(22)g_T^s=-0.00319(69)(2)(22), gTc=0.00263(269)(2)(37)g_T^c=-0.00263(269)(2)(37) in the MS\overline{\rm MS} scheme at 2~GeV. The first error is statistical, the second is the systematic error due to the renormalization and the third the systematic arising from possible contamination due to the excited states.Comment: 20 pages and 13 figure

    Development and validation of a postmortem radiological alteration index: the RA-Index

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    This study aimed to derive an index quantifying the state of alteration of cadavers by quantifying the presence of gas in the body using postmortem multidetector computed tomography (MDCT) imaging, and to validate the index by defining its sensitivity and specificity. The RA (radiological alteration)-index was derived from postmortem MDCT data from 118 nontraumatically deceased people. To validate the index, 100 additional scanned bodies (50 % traumatically deceased) were retrospectively examined by two independent observers. Presence of gas at 82 sites was assessed by a radiologist, whereas a forensic pathologist only investigated the seven sites used for the RA-index. The RA-index was highly correlated to the overall presence of gas in all 82 sites (R2 = 0.98 in the derivation set and 0.85 in the validation set). Semiquantitative evaluation of gas presence in each site showed moderate reliability (Cohen's kappa range, 0.41-0.78); nevertheless, the overall RA-index was very reliable (ICC2,1 = 0.95; 95 % CI 0.92-0.96). Examiner using the RA-index detected heart cavities full of gas with a sensitivity of 100 % (95 % CI 51.7-100) and a specificity of 98.8 % (92.6-99.9). We conclude that determining the presence of gas at seven sites is a valid means to measure the distribution of gas due to cadaveric alteration in the entire body. The RA-index is rapid, easy-to-use, and reliable for nonexperienced users, and it is a valid method to suspect the normal presence of gas from cadaveric alteration. MDCT can be used to screen for gas embolism and to give indications for gas composition analysis (gas chromatography

    Two types of all-optical magnetization switching mechanisms using femtosecond laser pulses

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    Magnetization manipulation in the absence of an external magnetic field is a topic of great interest, since many novel physical phenomena need to be understood and promising new applications can be imagined. Cutting-edge experiments have shown the capability to switch the magnetization of magnetic thin films using ultrashort polarized laser pulses. In 2007, it was first observed that the magnetization switching for GdFeCo alloy thin films was helicity-dependent and later helicity-independent switching was also demonstrated on the same material. Recently, all-optical switching has also been discovered for a much larger variety of magnetic materials (ferrimagnetic, ferromagnetic films and granular nanostructures), where the theoretical models explaining the switching in GdFeCo films do not appear to apply, thus questioning the uniqueness of the microscopic origin of all-optical switching. Here, we show that two different all-optical switching mechanisms can be distinguished; a "single pulse" switching and a "cumulative" switching process whose rich microscopic origin is discussed. We demonstrate that the latter is a two-step mechanism; a heat-driven demagnetization followed by a helicity-dependent remagnetization. This is achieved by an all-electrical and time-dependent investigation of the all-optical switching in ferrimagnetic and ferromagnetic Hall crosses via the anomalous Hall effect, enabling to probe the all-optical switching on different timescales.Comment: 1 page, LaTeX; classified reference number

    Hydrogen diffusion and densification in amorphous silicon

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    Diagnostic performance of urinary metanephrines for the postmortem diagnosis of hypothermia.

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    The purpose of this study was to assess the diagnostic potential of urinary metanephrines and 3-methoxytyramine compared to urinary catecholamine determination in diagnosing antemortem cold exposure and fatal hypothermia. 83 cases of fatal hypothermia and 144 control cases were included in this study. Catecholamines (adrenaline, noradrenaline and dopamine), metanephrines (metanephrine, normetanephrine) and 3-methoxytyramine were measured in urine collected during autopsy. All tested analytes were significantly higher in hypothermia cases compared to control subjects and displayed a generally satisfying discriminative value, thus indicating urinary catecholamines and their metabolites as reliable markers of cold-related stress and hypothermia related-deaths. Metanephrine and adrenaline had the best discriminative value between hypothermia and control cases compared to other tested analytes, though with different sensitivity and specificity. These can therefore be considered the most suitable markers of cold-related stress

    La situation financière des grands groupes français demeure solide au premier semestre 2011.

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    Les grands groupes confirment leurs bonnes performances au cours du premier semestre 2011 à tous les niveaux : résultats, investissements, structure financière, trésorerie. Des éléments d’incertitude apparaissent : la conjoncture, la volatilité de certaines composantes des fonds propres et du résultat (goodwill, écarts de conversion…).comptes consolidés IFRS, résultats, grandes entreprises industrielles et commerciales, grands groupes français, other comprehensive income (OCI), entreprises cotées au compartiment A d’Euronext.

    Problematic clinical features of powered wheelchair users with severely disabling multiple sclerosis

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    This article is made available through the Brunel Open Access Publishing Fund. Copyright @ 2014 Informa UK Ltd.Purpose: The aim of this study is to describe the clinical features of powered wheelchair users with severely disabling multiple sclerosis (MS) and explore the problematic clinical features influencing prescription. Method: Retrospective review of electronic and case note records of recipients of electric-powered indoor/outdoor powered wheelchairs (EPIOCs) attending a specialist wheelchair service between June 2007 and September 2008. Records were reviewed by a consultant in rehabilitation medicine, data systematically extracted and entered into a computer database. Further data were entered from clinical records. Data were extracted under three themes; demographic, diagnostic, clinical and wheelchair factors. Results: Records of 28 men mean age 57 (range 37–78, SD 12) years and 63 women mean age 57 (range 35–81, SD 11) years with MS were reviewed a mean of 64 (range 0–131) months after receiving their wheelchair. Twenty two comorbidities, 11 features of MS and 8 features of disability were thought to influence wheelchair prescription. Fifteen users were provided with specialised seating and 46 with tilt-in-space seats. Conclusions: Our findings suggest that people with severe MS requiring an EPIOC benefit from a holistic assessment to identify problematic clinical features that influence the prescription of the EPIOC and further medical and therapeutic interventions

    Multi-phase postmortem CT angiography: recognizing technique-related artefacts and pitfalls

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    Background and purpose: Multi-phase postmortem CT angiography (MPMCTA) is increasingly being recognized as a valuable adjunct medicolegal tool to explore the vascular system. Adequate interpretation, however, requires knowledge about the most common technique-related artefacts. The purpose of this study was to identify and index the possible artefacts related to MPMCTA. Material and methods: An experienced radiologist blinded to all clinical and forensic data retrospectively reviewed 49 MPMCTAs. Each angiographic phase, i.e. arterial, venous and dynamic, was analysed separately to identify phase-specific artefacts based on location and aspect. Results: Incomplete contrast filling of the cerebral venous system was the most commonly encountered artefact, followed by contrast agent layering in the lumen of the thoracic aorta. Enhancement or so-called oedematization of the digestive system mucosa was also frequently observed. Conclusion: All MPMCTA artefacts observed and described here are reproducible and easily identifiable. Knowledge about these artefacts is important to avoid misinterpreting them as pathological finding
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