65 research outputs found

    A very simple method to measure the input capacitance and the input current of transistors

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    Abstract We describe a method to measure the gate capacitance and the gate current of transistors at any temperature and at any operating condition. Discrimination between the total input capacitance and transfer reverse capacitance (gate to drain capacitance) is also possible with high accuracy. With this data the optimization of the signal to noise ratio and power dissipation can be achieved in the design of the front-end electronics for nuclear applications

    Temperature characterization of deep and shallow defect centers of low noise silicon JFETs

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    Abstract We have selected different low noise JFET processes that have shown outstanding dynamic and noise performance at both room temperature and low temperatures. We have studied JFETs made with a process optimized for cryogenic operation, testing several devices of varying capacitance. For most of them, we have been able to detect the presence of shallow individual traps at low temperature which create low frequency (LF) Generation–Recombination (G–R) noise. For one device type no evidence of traps has been observed at the optimum temperature of operation (around 100 K). It had a very small residual LF noise. This device has been cooled down to 14 K. From below 100 K down to 14 K the noise was observed to increase due to G–R noise originating from donor atoms (dopants) inside the channel. A very simple theoretical interpretation confirms the nature of G–R noise from these very shallow trapping centers. We also studied devices from a process optimized for room temperature operation and found noise corresponding to the presence of a single deep level trap. Even for this circumstance the theory was experimentally confirmed. The measurement approach we used allowed us to achieve a very high accuracy in the modeling of the measured G–R noise. The ratio of the density of the atoms responsible for G–R noise above the doping concentration, NT/Nd, has been verified with a sensitivity around 10−7

    Customer-driven management models for choiceless clientele? Business process reengineering in a California welfare agency

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    Business process reengineering and lean are increasingly used to restructure public sector work. This article presents a case study of reengineering in a California welfare agency. It finds extensive work intensification and reduced autonomy for the workforce, and deteriorating service for the clientele. Rather than attribute these outcomes as inherent to the business process reengineering model, this article emphasizes how cost cutting and quantitative efficiency were prioritized over worker empowerment and service quality because the organization is a government agency facing severe budgetary pressures under neoliberalism, and the clientele consists of indigent families and individuals who have no choice of an alternative provider. © 2015, SAGE Publications. All rights reserved

    Putative Key Role of Inositol Messengers in Endothelial Cells in Preeclampsia

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    Immunological alterations, endothelial dysfunction, and insulin resistance characterize preeclampsia. Endothelial cells hold the key role in the pathogenesis of this disease. The signaling pathways mediating these biological abnormalities converge on PKB/Akt, an intracellular kinase regulating cell survival, proliferation, and metabolism. Inositol second messengers are involved in metabolic and cell signaling pathways and are highly expressed during preeclampsia. Intracellular action of these molecules is deeply affected by zinc, manganese, and calcium. To evaluate the pathophysiological significance, we present the response of the intracellular pathways of inositol phosphoglycans involved in cellular metabolism and propose a link with the disease

    Comparison of endometrial polyp recurrence in fertile women after office hysteroscopic endometrial polypectomy using two widely spread techniques

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    Aim: To compare the recurrence of benign endometrial polyps after office hysteroscopic polypectomy performed with a bipolar electrode (BE) or a small diameter hysteroscopic tissue removal system (HTRs). Methods: From July 2018 to December 2019 we evaluated the charts of 114 asymptomatic fertile women who underwent office hysteroscopic polypectomy, 1 year before, for a single large benign endometrial polyp (size between 10 and 20 mm) using a 4 mm continuous flow hysteroscope with a BE or a 5 mm HTRs. Patients, divided into two groups according to surgical procedure, each performed exclusively by one expert gynecologist, were scheduled for a 12-month postoperative transvaginal sonography to evaluate the recurrence of endometrial polyps. Results: Forty-eight women of the BE group and 42 of the HTRs group were considered for the 1-year transvaginal sonography follow-up. Five polyps were identified in the BE group and three in the HTRs group (5/48 vs 3/42, P = n.s.). All polyps were removed hysteroscopically (in three out of five and in two out of three cases, respectively, in the same places of the previous polypectomy) and evaluated as ‘benign’ by the pathologist. Conclusion: Office hysteroscopic endometrial polypectomy with small HTRs compared to BE revealed at a 1-year follow-up no difference in terms of complete removal and recurrence of polyps. HTRs polypectomy resulted in less pain and significantly quicker time of procedure compared to BE. This data should be kept in mind for patient comfort any time hysteroscopic polypectomy is planned in an office setting

    The front-end readout for CUORICINO, an array of macro-bolometers and MIBETA, an array of Ό-bolometers

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    The front-end approach for the readout of two arrays of bolometric detectors is described. The first front-end is for an array of m-bolometers, while the second is for an array of macro-bolometers. Analogies and differences in the adopted strategies are put into evidence

    Low frequency noise characterization of very large value resistors

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    A very simple circuit configuration is described which allows to characterize the noise of very large value resistors. With this measurement setup we investigated the low frequency noise of large value resistors, tens of G/spl Omega/ range, realized with different technologies, at different bias voltages. A technique is suggested that allows to reduce the low frequency noise contribution, by optimizing the connecting arrangement. A short review of the resistor noise theory is given

    CUORE: A Cryogenic Underground Observatory for Rare Events

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    CUORE is a proposed tightly packed array of 1000 TeO2 bolometers, each being a cube 5 cm on a side with a mass of 760 g. The array consists of 25 vertical towers, arranged in a square of 5 towers by 5 towers, each containing 10 layers of 4 crystals. The design of the detector is optimized for ultralow-background searches: for neutrinoless double beta decay of 130Te (33.8% abundance), cold dark matter, solar axions, and rare nuclear decays. A preliminary experiment involving 20 crystals 3x3x6 cm3 of 340 g has been completed, and a single CUORE tower is being constructed as a smaller scale experiment called CUORICINO. The expected performance and sensitivity, based on Monte Carlo simulations and extrapolations of present results, are reported.Comment: 39 pages, 12 figures, submitted to NI
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