226 research outputs found

    MOSAIC: An integrated ultrasonic 2-D array system

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    An investigation into the development of an ultrasound imaging system capable of customization for multiple applications via the tessellation of in-system programmable scalable modules, or tiles, is presented here. Each tile contains an individual ultrasonic array, operating at +/-3.3V, which can be assembled into a larger ‘mosaic’ of multiple tiles to create arrays of any size or shape. The ability to form an imaging system from generic building blocks which are physically identical for manufacturing purposes yet functionally unique via programming to suit the application has many potential benefits in the field of ultrasonics. The system is primarily targeted at underwater sonar and non-destructive testing, as defined by the current excitation frequency, but the concept is equally applicable to applications in biomedical ultrasound

    A modular FPGA-based ultrasonic array system for applications including non-destructive testing

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    This paper reports work aimed at the development of an ultrasonic imaging system comprising modular, reprogrammable building blocks, or tiles, which can be customised for multiple applications, including and within non-destructive testing (NDT), by the user. The key component is an autonomous module containing the ultrasonic array and all the electronics necessary to operate it. This contrasts with most previous research on system integration which has focused only on the transducer and front-end electronics.<p></p> In the present work, a 4 4 element 2D piezoelectric array with a 16 mm 16 mm aperture has been produced, with the entire transmission and reception electronics within the same footprint. The proximity of the transducer array and electronics removes the need for cabling, reducing signal degradation due to cross talk and interference. In addition, it avoids the problem of electrical impedance matching of cable between the array elements and the electronics. <p></p> Pulse-echo insertion loss of 48 dB has been measured from back-wall reflections in 73 mm-thick aluminium without decoding, and results with decoded signals show adequate signal-to-noise ratio (SNR) with 3.3 V excitation at an operating frequency of 1.2 MHz, within the range required for deep penetration in nuclear power plant. <p></p> Crucially, the ability to construct 2D arrays of any size and shape from generic building blocks represents a departure from almost all previous work in ultrasound, which has traditionally been highly application specific. This may allow ultrasonic NDT to be used in applications for which the investment in customised devices could not previously be justified. <p></p&gt

    MOSAIC: A Scalable reconfigurable 2D array system for NDT

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    This paper documents the development of a scalable 2D array system, or Mosaic that can be targeted at a wide range of NDT applications by way of a reconfigurable tile that can be tessellated to form arrays of any size and shape. Close coupling permits utilization of excitation voltages as low as +/-3.3V with insertion loss of 48dB on reflection from an aluminum back wall at 73mm achieved using 2D arrays without decoding

    Quand le téléphone ne chauffe pas : les hotlines psy en situation de pandémie [When hotlines remain cold: Psychological support in the time of pandemic]

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    In Switzerland and elsewhere, many psychological support hotlines were set up during the acute phase of the COVID-19 pandemic. Specialists in psychological first aid, in charge of developing and managing these hotlines, had to face an unknown situation, very different from the disasters for which they prepare themselves. Since the pandemic and the associated physical distancing were a potential threat to social cohesion, one could make the hypothesis that, by setting up hotlines, these professionals sought to reintroduce a form of proximity and to care for and cultivate the social connections among people. The pressure, feelings of emergency, anxious anticipation and expectation of the political authorities and the population may have favoured the development of these structures. Other factors certainly also played a role, such as the need to be useful and to exist as professional, or the need to act in order to reduce anxiety related to the pandemic. Altogether, these hotlines were little used, and their usefulness may be questioned. Similar phenomena have been observed - especially in the sanitary domain - with a multiplication of new offers, not always adjusted to specific identified needs, while health care services were on the same time under-used. Our observations plead against emergency responses in crisis situations and for reflecting on the measures to be put in place rather than to "act" them

    The implementation and first insights of the French-speaking Swiss programme for monitoring self-harm.

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    Self-harm is a major risk factor for suicide but remains poorly documented. No data on self-harm in French-speaking Switzerland exist. To address this deficiency, the Swiss Federal Office of Public Health commissioned a specific self-harm monitoring programme. We present and discuss its implementation and first findings. Every patient aged 18–65 years presenting for self-harm to the emergency departments of the Lausanne and Neuchâtel general hospitals were included in the monitoring programme over a 10-month period (December 2016 to September 2017). Clinicians collected anonymous sociodemographic and clinical data. The sample included 490 patients (54.9% female and 45.1% male) for 554 episodes of self-harm, showing a higher proportion of patients aged 18–34 (49.2%) than older age groups (35–49, 33.7% and 50–65, 17.1%). Patients were mostly single (56.1%) and in problematic socioeconomic situations (65.7%). Self-poisoning was the most commonly used method (58.2%) and was preferred by women (71% of females and 42.5% of males, Fisher’s exact test, p <0.001) and the majority of patients (53.3%) had experienced at least one previous episode of self-harm. The self-harm rate was 220 per 100,000 inhabitants in Lausanne and 140 in Neuchâtel. Suicidal intent was clear for 50.6% of the overall sample, unclear for 25.1% and absent for 24.3%. It differed significantly between sites (χ2(2) = 9.068, p = 0.011) as Lausanne reported more incidents of unclear intent (27.7% versus 17.4% in Neuchâtel) and Neuchâtel more incidents with absence of intent (33.1% versus 21.3% in Lausanne). In Lausanne, patients more frequently resorted to methods such as jumping from a height (11.4%) and hanging (9%) than in Neuchâtel (1.6% and 4.9%, Fisher’s exact test, p = 0.006). Our results are globally consistent with previous research on self-harm. We found significant inter-site differences in methods, suicidal intent and self-harm rates. Our findings highlight the importance of implementing local self-harm monitoring to identify specific at-risk groups and develop targeted preventive intervention

    Photoperiodic Modulation of Circadian Clock and Reproductive Axis Gene Expression in the Pre-Pubertal European Sea Bass Brain

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    The acquisition of reproductive competence requires the activation of the brain-pituitary-gonad (BPG) axis, which in most vertebrates, including fishes, is initiated by changes in photoperiod. In the European sea bass long-term exposure to continuous light (LL) alters the rhythm of reproductive hormones, delays spermatogenesis and reduces the incidence of precocious males. In contrast, an early shift from long to short photoperiod (AP) accelerates spermatogenesis. However, how photoperiod affects key genes in the brain to trigger the onset of puberty is still largely unknown. Here, we investigated if the integration of the light stimulus by clock proteins is sufficient to activate key genes that trigger the BPG axis in the European sea bass. We found that the clock genes clock, npas2, bmal1 and the BPG genes gnrh, kiss and kissr share conserved transcription factor frameworks in their promoters, suggesting co-regulation. Other gene promoters of the BGP axis were also predicted to be co-regulated by the same frameworks. Co-regulation was confirmed through gene expression analysis of brains from males exposed to LL or AP photoperiod compared to natural conditions: LL fish had suppressed gnrh1, kiss2, galr1b and esr1, while AP fish had stimulated npas2, gnrh1, gnrh2, kiss2, kiss1rb and galr1b compared to NP. It is concluded that fish exposed to different photoperiods present significant expression differences in some clock and reproductive axis related genes well before the first detectable endocrine and morphological responses of the BPG axis.European Community [222719 - LIFECYCLE]; Foundation for Science and Technology of Portugal (FCT) [SFRH/BPD/66742/2009, PEst-C/MAR/LA0015/2011]; Valencian Regional Goverment [Prometeo II/2014/051]; Spanish Ministry of Science and Innovation (MICINN) [CSD 2007-0002]info:eu-repo/semantics/publishedVersio

    NEDA—NEutron Detector Array

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    The NEutron Detector Array, NEDA, will form the next generation neutron detection system that has been designed to be operated in conjunction with Îł-ray arrays, such as the tracking-array AGATA, to aid nuclear spectroscopy studies. NEDA has been designed to be a versatile device, with high-detection efficiency, excellent neutron-Îł discrimination, and high rate capabilities. It will be employed in physics campaigns in order to maximise the scientific output, making use of the different stable and radioactive ion beams available in Europe. The first implementation of the neutron detector array NEDA with AGATA 1π was realised at GANIL. This manuscript reviews the various aspects of NEDA
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