1,721,123 research outputs found
Advances in brain imaging: a new ethical challenge.
No full textTechnical advances in the past 25 years permitted substantial advances in the neuroimaging field, expanding the diagnostic and research potentials and significantly reducing the use of old invasive imaging techniques for research purposes. The safer procedures now available allow acquisition of reference data, morphological assessment and functional characterisation from healthy volunteers. However, enrollment of volunteers is still a sensitive ethical issue. Ethical problems related to informed consent, for both research and diagnostic procedures, in patients with neuropsychiatric disorders represent an additional crucial issue. Furthermore, with both functional and structural neuroimaging studies, there is a theoretical risk of violation of individual privacy. Research in the neuroimaging field should tend to increase the amount of information obtained through appropriate post-processing procedures, including multimodality image fusion, and to limit stress and discomfort
A transfer-free wafer-scale CVD graphene fabrication process for MEMS/NEMS sensors
No full textIn this paper we report a novel transfer-free graphene fabrication process, which does not damage the graphene layer. Uniform graphene layers on 4 silicon wafers were deposited by chemical vapor deposition using the CMOS compatible Mo catalyst. Removal of the Mo layer after graphene deposition results in a transfer-free and controlled placement of the graphene on the underlying SiO2. Moreover, pre-patterning the Mo layer allows customizable graphene geometries to be directly obtained, something that has never been achieved before. This process is extremely suitable for the large-scale fabrication of MEMS/NEMS sensors, especially those benefitting from specific properties of graphene, such as gas sensing. © 2016 IEEE
High sensitive gas sensors realized by a transfer-free process of CVD graphene
No full textThe work herein presented investigates the behavior of graphene-based gas sensors realized by using an innovative way to prepare graphene. The sensing layer was directly grown by chemical vapor deposition on pre-patterned CMOS compatible Mo catalyst and then it was eased on the underlying SiO2 through a completely transfer-free process. Devices with different geometries were designed and tested towards NO2 and NH3 in environmental conditions, i.e. room temperature and relative humidity set at 50%. Furthermore, these gas sensors were also calibrated, resulting in the ability to detect concentrations down to 240 ppb and 17 ppm of NO2 and NH3, respectively. These results are in agreement with the best performances reported in literature for graphene-based sensors. They not only confirm the successful devices fabrication through the transfer-free approach, but also pave the route for large-scale production of MEMS/NEMS sensors. © 2016 IEEE
An innovative approach to overcome saturation and recovery issues of CVD graphene-based gas sensors
No full textIn this work, we present an innovative method which enables to solve fundamental limitations affecting graphene-based chemi-sensors operating under environmental conditions, namely the lack of signal saturation and the scarce recovery after the detection step. The method, which exploits the differential current instead of the current itself, is validated by applying it on different devices having an exposed area equal to 512 pm2. The analysis is performed by adopting nitrogen dioxide (NO2) as target gas in the range from 0.12 ppm to 1.5 ppm. The approach reliability is further confirmed by performing sensing tests towards NO2 with the relative humidity set at two different levels, 30% and 50%. © 2017 IEEE
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The use of single-photon emission computed tomography in cardiology
No full textThe tomographic distribution of thallium 201 in the myocardium was studied with a gamma camera with 2 detectors (29 cms in diameter) with 37 photo multipliers each. The camera was connected to a PDP computer with a 256 Kbytes memory. Thallium 201 in a dose of about 74 MBq 2 mCi was used in normal subjects, patients with coronary artery disease and with cardiac hypertrophy. Tomographic sections were obtained every 1.2 cms in the sagittal and frontal projections. The distribution of the Thallium was uniform in normal and hypertrophic hearts. Focal defects were seen in C.A.D. Single-photon emission computerized tomography was instrumental in determining the extension of the damage of the myocardium to areas which appeared normal in the regular thallium 201 scintigrams
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