3,262 research outputs found

    Components Qualification for a Possible use in the Mu2e Calorimeter Waveform Digitizers

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    The Mu2e experiment at Fermilab searches for the charged flavor violating conversion of a muon into an electron in the Coulomb field of a nucleus. The detector consists of a straw tube tracker and a CSI crystal electromagnetic calorimeter, both housed in a superconducting solenoid. Both the front-end and the digital electronics, located inside the cryostat, will be operated in vacuum under a 1 T magnetic field, having to sustain the high flux of neutrons and ionizing particles coming from the muons stopping target. These harsh experimental conditions make the design of the calorimeter waveform digitizer quite challenging. All the selected commercial devices must be tested individually and qualified for radiation hardness and operation in high magnetic field. At the moment the expected particles flux and spectra at the digitizers location are not completely simulated and we are using initial rough estimates to select the components for the first prototype. We are gaining experience in the qualification procedures using the selected components but the choice will be frozen only when dose and neutron flux simulations will be completed. The experimental results of the first qualification campaign are presented.Comment: TWEPP 2016 - Topical Workshop on Electronics for Particle Physics, 26-30 September 2016, Karlsruhe Institute of Technology (KIT

    The diagnostic accuracy of the small fiber neuropathy symptoms inventory questionnaire (SFN-SIQ) for identifying pure small fiber neuropathy

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    A definite diagnosis of pure small fiber neuropathy (SFN) relies on specific diagnostic testing, such as skin biopsy, quantitative sensory testing (QST), and nociceptive evoked potentials, which require considerable resources that may not be widely available. Accordingly, diagnostic tools with easy implementation in non-specialist centers are warranted to identify patients who require second-level diagnostic tests. In this study, we aimed to test the accuracy of the Small Fiber Neuropathy Symptoms Inventory Questionnaire (SFN-SIQ) in diagnosing pure SFN. We enrolled 86 patients with suspected pure SFN. In these patients, we calculated the diagnostic accuracy of the SFN-SIQ using a combination of clinical examination, QST, and skin biopsy as a reference standard. We found that the SFN-SIQ showed an excellent ability to discriminate between patients with and without pure SFN, with 86% sensitivity and 70% specificity in the diagnosis of pure SFN. Our study providing the diagnostic yield of the SFN-SIQ for pure SFN diagnosis suggests that this questionnaire might be used to screen patients with suspected SFN and identify those requiring second-level diagnostic tests such as QST, skin biopsy, or nociceptive evoked potentials

    Flood hazard of the Somma-Vesuvius region based on historical (19-20th century) and geomorphological data

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    This paper presents a preliminary susceptibility map of the flood hazard for the Somma-Vesuvius volcanic district, worked out by means of multidisciplinary historical, geological, geomorphological and rainfall data processing. It is well known that the Somma-Vesuvius volcano, due to its explosive volcanism and the dense urbanization of the surrounding area, with a population exceeding 650,000 is one of the most dangerous active volcanoes of the world. Although this area has been extensively studied from the volcanological point of view with regards to its volcanic hazard, there are currently not many detailed studies about its flood hazard factors, despite the fact that, in the last century, many intense rainfall events in this area have produced several floods that invaded the surrounding plains affecting towns and roads, and causing much damages and loss of lives. Accordingly, in this paper high-resolution DEM (5×5 m pixel) and detailed geomorphological maps of the whole area have been analyzed and processed in GIS environment, carrying out a comparative study of the present-day morphology and the morphology of the 1900’s volcanic edifice, including changes of infrastructures and buildings throughout the last century. These results, together with historical chronicles data and the rainfall accurate data for all flood events, have been processed in this paper for highlighting the drainage basins areas of Somma-Vesuvius where the flood phenomena could be more probable in the future, working out a preliminary zoning map, also suggesting in which sectors interventions useful for mitigation of flood risk should be implemented

    Tunneling mediated by conical waves in a 1D lattice

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    The nonlinear propagation of 3D wave-packets in a 1D Bragg-induced band-gap system, shows that tranverse effects (free space diffraction) affect the interplay of periodicity and nonlinearity, leading to the spontaneous formation of fast and slow conical localized waves. Such excitation corresponds to enhanced nonlinear transmission (tunneling) in the gap, with peculiar features which differ on the two edges of the band-gap, as dictated by the full dispersion relationship of the localized waves.Comment: 5 pages, 6 figure

    Simulation and modelling of transient electric fields in hvdc insulation systems based on polarization current measurements

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    Simulating and modelling electric field dynamics in the insulation of medium-and high-voltage DC electrical systems is needed to support insulation design optimization and to evaluate the impact of voltage transients on ageing mechanisms and insulation reliability. In order to perform accurate simulations, appropriate physical models must be adopted for the insulating material properties, particularly conductivity, which drives the electric field in a steady-state condition and contributes to determining the field behavior during voltage and load transients. In order to model insulation conductivity, polarization, and conduction, mechanisms must be inferred through charging and discharging current measurements, generally performed at different values of electric field and temperatures in flat specimens of the material under study. In general, both mechanisms are present, but one of them may be predominant with respect to the other depending on type of material. In this paper, we showed that models based on predominant polarization mechanisms were suitable to describe impregnated paper, but not polymers used for HV and MV DC insulation. In the latter case, indeed, trapping–detrapping and conduction phenomena were predominant compared to polarization, thus conductivity models had to be considered, in addition to or as a replacement of the polarization model, in order to carry out proper electric field simulations

    Pain associated with COVID-19 vaccination is unrelated to skin biopsy abnormalities

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    Previous clinical observations raised the possibility that COVID-19 vaccination might trigger a small-fibre neuropathy.Objectives:In this uncontrolled observational study, we aimed to identify small fibre damage in patients complaining of generalized sensory symptoms and pain after COVID-19 vaccination.Methods:We collected clinical data, including a questionnaire for assessing autonomic symptoms (Composite Autonomic Symptom Score-31), and investigated quantitative sensory testing (QST) and skin biopsy in 15 prospectively enrolled patients with generalized sensory symptoms and pain after COVID-19 vaccination. Nine patients complaining of orthostatic intolerance also underwent cardiovascular autonomic tests.Results:We found that all patients experienced widespread pain, and most of them (11 of 15) had a fibromyalgia syndrome. All patients had normal skin biopsy findings, and in the 9 patients with orthostatic intolerance, cardiovascular autonomic tests showed normal findings. Nevertheless, 5 patients had cold and warm detection abnormalities at the QST investigation.Conclusions:In our study, most patients complaining of generalized sensory symptoms and pain after COVID-19 vaccination had clinical and diagnostic test findings compatible with a fibromyalgia syndrome. Although the abnormal QST findings we found in 5 patients might be compatible with a small-fibre neuropathy, they should be cautiously interpreted given the psychophysical characteristics of this diagnostic test. Further larger controlled studies are needed to define precisely the association between small fibre damage and COVID-19 vaccination

    Colonic metastasis from breast carcinoma detection by CESM and PET/CT: A case report

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    Introduction: Metastatic spread in invasive lobular carcinoma (ILC) of breast mainly occurs in bones, gynecological organs, peritoneum, retroperitoneum, and gastrointestinal (GI) tract. Metastases to the GI tract may arise many years after initial diagnosis and can affect the tract from the tongue to the anus, stomach being the most commonly involved site. Clinical presentations are predominantly nonspecific, and rarely asymptomatic. CEA, CA 15-3, and CA 19-9 may be informative for symptomatic patients who have had a previous history of breast cancer. Case presentation: We introduce the case of asymptomatic colonic metastasis from breast carcinoma in a 67-year-old woman followed-up for Luminal A ILC. Diagnosis was performed through positron emission tomography/computed tomography (PET/CT) scan and contrast-enhancement spectral mammography (CESM), steering endoscopist to spot the involved intestinal tract and in ruling out further dissemination in the breast parenchyma. Conclusion: In colonic metastases, tumor markers might not be totally reliable. In asymptomatic cases, clinical conditions might be underappreciated, missing local or distant recurrence. CT and PET/CT scan might be useful in diagnosing small volume diseases, and steering endoscopist toward GI metastasis originating from the breast. CESM represents a tolerable and feasible tool that rules out multicentricity and multifocality of breast localization. Moreover, particular patients could tolerate it better than magnetic resonance imaging (MRI)

    Response of the Pacific Sector of the Southern Ocean to wind stress variability from 1995 to 2017

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    AbstractDrifter, satellite, expendable bathythermograph (XBT), and Argo float data are used to study the response of the Pacific Sector of the Southern Ocean (PSSO) to the wind stress field in the period 1995–2017, in terms of eddy field, water mass transport, and heat fluxes at large and regional scales. Increasing wind stress over the PSSO in those two decades led to a growth of the Eddy Kinetic Energy (EKE) in the region of the Antarctic Circumpolar Current (ACC). Increases of the EKE occur with delays of 1–4 years with respect to peaks in the zonal component of the wind stress. The persistent ACC meander located south of New Zealand (between 150°E and 180°W and 50°S to 66°S) responds to the interannual wind variations earlier than the entire ACC branch in the PSSO. In the same area, an estimate of the ACC transport based on in situ data shows interannual variability but no significant decadal trend over the study period. The effects of the EKE variability on the meridional eddy heat fluxes are significant on interannual scales. The strengthening of the EKE field leads to a local increase in the poleward meridional eddy heat fluxes in the PSSO, especially in the ACC band. The weakening of the EKE field defines an area of equatorward meridional eddy heat fluxes in the middle of the PSSO (south of 40°S, between 130°W and 160°W) and prevalent poleward fluxes in the further western and eastern regions

    How different experimental models of secondary hyperalgesia change the nociceptive flexion reflex

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    In this neurophysiological study in healthy humans, we assessed how central sensitization induced by either high-frequency stimulation (HFS) or topical capsaicin application modulates features of the RIII reflex response. The ability of these stimuli to engage the endogenous pain modulatory system was also tested. In 26 healthy participants we elicited an RIII reflex using suprathreshold stimulation of the sural nerve. Subsequently HFS or capsaicin were applied to the foot and the RIII reflex repeated after 15 minutes. Contact heating of the volar forearm served as the heterotopic test stimulus to probe activation of the endogenous pain modulatory system. HFS significantly reduced the pain threshold by 29% and the RIII reflex threshold by 20%. Capsaicin significantly reduced the pain threshold by 17% and the RIII reflex threshold by 18%. Both HFS and capsaicin left RIII reflex size unaffected. Numerical Rating Scale (NRS) pain scores elicited by the heterotopic noxious heat stimulus were unaffected by capsaicin and slightly increased by HFS. HFS and capsaicin similarly modulated the pain threshold and RIII reflex threshold, without a concomitant inhibitory effect of the endogenous pain modulatory system. Our neurophysiological study supports the use of the RIII reflex in investigating central sensitization in humans

    Laser Writing of Parabolic Micromirrors with a High Numerical Aperture for Optical Trapping and Rotation

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    On-chip optical trapping systems allow for high scalability and lower the barrier to access. Systems capable of trapping multiple particles typically come with high cost and complexity. Here we present a technique for making parabolic mirrors with micron-size dimensions and high numerical apertures (NA>1). Over 350 mirrors are made by simple CO2 laser ablation of glass followed by gold deposition. We fabricate mirrors of arbitrary diameter and depth at a high throughput rate by carefully controlling the ablation parameters. We use the micromirrors for 3-dimensional optical trapping of microbeads in solution, achieving a maximum optical trap stiffness of 52 pN/{\mu}m/W. We then further demonstrate the viability of the mirrors as in-situ optical elements through the rotation of a vaterite particle using reflected circularly polarized light. The method used allows for rapid and highly customizable fabrication of dense optical arrays.Comment: 6 pages, 5 figure
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