排序方式： 共有83条查询结果，搜索用时 15 毫秒
51.
Lorenzo Righetto Alessandro Spelta Emanuele Rabosio Fabio Pammolli 《Journal of Informetrics》2019,13(2):583-592
Within the perimeter of patent collaboration networks, the average distance of collaborations and the number of countries involved per each collaboration have been shown to have increased steadily in time. Less attention, though, has been devoted to assessing whether this growth of cross-country collaborations is stable in time. To address this scientific question we focus on the identification of long-term correlations (i.e. temporal persistence). Our data set consists of time series of yearly average collaboration radii and of cross-border links in the Euro-American subsystem of the global collaboration network for the period 1978–2014. To investigate the fundamental persistence properties of these time series, we use Detrended Fluctuation Analysis, a method that allows us to measure long-term correlations in detrended signals. Also, we devise a general and original procedure to assess the statistical significance of results for short time series. Our results, showing that long-term correlations do exist in the majority of our signals, reinforce the hypothesis of a diminishing role of geographical distance in technological collaborations. Results at national level show that a significant degree of heterogeneity in persistence parameters can be detected within Europe, irrespectively of the efforts towards the set-up of an integrated European Research Area. 相似文献
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Lazaro Alessandro Soares Nunes Sayeeda Mussavira Omana Sukumaran Bindhu 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2015,25(2):177-192
This systematic review presents the latest trends in salivary research and its applications in health and disease. Among the large number of analytes present in saliva, many are affected by diverse physiological and pathological conditions. Further, the non-invasive, easy and cost-effective collection methods prompt an interest in evaluating its diagnostic or prognostic utility. Accumulating data over the past two decades indicates towards the possible utility of saliva to monitor overall health, diagnose and treat various oral or systemic disorders and drug monitoring. Advances in saliva based systems biology has also contributed towards identification of several biomarkers, development of diverse salivary diagnostic kits and other sensitive analytical techniques. However, its utilization should be carefully evaluated in relation to standardization of pre-analytical and analytical variables, such as collection and storage methods, analyte circadian variation, sample recovery, prevention of sample contamination and analytical procedures. In spite of all these challenges, there is an escalating evolution of knowledge with the use of this biological matrix.Key words: saliva, non-invasive, biological markers, drug monitoring, oral health 相似文献
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A number of recent studies have measured the extent and timing of segment rotation during the golf swing. A promising technique, instantaneous screw axis (ISA) theory, could provide a better expression of segment rotation. In Part 1 of this two-part study, the objectives are to identify the ISA of the pelvis, shoulders and left arm during the downswing, compute segment angular velocity relative to that segment’s ISA and verify that ISA theory is a valid tool to analyse segment rotation during the golf swing. Results indicate that for all subjects, at least 71% of marker velocity is a result of rotation about their respective ISA, when averaging results over the duration of the downswing, confirming that motion is primarily rotational. Furthermore, ISA position and orientation of each segment approaches, on average, the expected gross axis of rotation, confirming that motion about the ISA is representative of joint motion. 相似文献
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Nicoletta Marinoni Alessandro Pavese Roberto Bugini Giuseppe Di Silvestro 《Journal of Cultural Heritage》2002,3(4):915
Black limestone samples from the quarries of Varenna (Lecco, I), Cene (Bergamo, I) and Riva di Solto (Bergamo, I) and widely used in Lombard architecture have been studied in terms of mineralogical, petrographic and chemical properties in order to provide a detailed characterisation and allow an unambiguous determination of their provenance. The inorganic and organic fractions have been separated from each other, and investigated using X-ray powder diffraction, atomic absorption, Hg-porosimetry, high performance liquid chromatography, gas chromatography, nuclear magnetic resonance and Fourier transform infrared spectroscopy. The occurrence of specific mineral phases, some binary chemical patterns (Fe/Mn, Zn/Sr, Zn/Co and Na/Cd) and the carbon chain relative molecular masses has proven to be useful markers to characterise unequivocally the materials studied. 相似文献
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This paper deals with the distributed tracking control of a heat process having uncertain diffusivity and subject to a distributed disturbance whose L2 norm is bounded by a constant which is not known a priori. Under certain regularity assumptions on the disturbance and on the chosen reference profile, a distributed unit-vector control, with an adaptive magnitude, is designed which provides the asymptotic tracking of the reference. The logic governing the gain adaptation is gradient-based and monodirectional, i.e. the gain cannot decrease over time. Lyapunov arguments are invoked to support the convergence properties of the proposed scheme, whose performance are also investigated by means of computer simulations. 相似文献
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German Posada Ting Lu Jill Trumbell Garene Kaloustian Marcel Trudel Sandra J. Plata Paola P. Peña Jennifer Perez Susana Tereno Romain Dugravier Gabrielle Coppola Alessandro Constantini Rosalinda Cassibba Kiyomi Kondo‐Ikemura Magaly Nóblega Ines M. Haya Claudia Pedraglio Manuela Verissimo Antonio J. Santos Ligia Monteiro Keng‐Ling Lay 《Child development》2013,84(6):1896-1905
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Giuseppe Familiari Michela Relucenti Rosemarie Heyn Rossella Baldini Giancarlo D'Andrea Pietro Familiari Alessandro Bozzao Antonino Raco 《Anatomical sciences education》2013,6(5):294-306
Neuroanatomy is considered to be one of the most difficult anatomical subjects for students. To provide motivation and improve learning outcomes in this area, clinical cases and neurosurgical images from diffusion tensor imaging (DTI) tractographies produced using an intraoperative magnetic resonance imaging apparatus (MRI/DTI) were presented and discussed during integrated second‐year neuroanatomy, neuroradiology, and neurosurgery lectures over the 2008–2011 period. Anonymous questionnaires, evaluated according to the Likert scale, demonstrated that students appreciated this teaching procedure. Academic performance (examination grades for neuroanatomy) of the students who attended all integrated lectures of neuroanatomy, was slightly though significantly higher compared to that of students who attended these lectures only occasionally or not at all (P=0.04). Significantly better results were obtained during the national progress test (focusing on morphology) by students who attended the MRI/DTI‐assisted lectures, compared to those who did so only in part or not at all, compared to the average student participating in the national test. These results were obtained by students attending the second, third and, in particular, the fourth year (P≤0.0001) courses during the three academic years mentioned earlier. This integrated neuroanatomy model can positively direct students in the direction of their future professional careers without any extra expense to the university. In conclusion, interactive learning tools, such as lectures integrated with intraoperative MRI/DTI images, motivate students to study and enhance their neuroanatomy education. Anat Sci Educ 6: 294–306. © 2013 American Association of Anatomists. 相似文献
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Ben Martz Thomas C. Neil Alessandro Biscaccianti 《Decision Sciences Journal of Innovative Education》2003,1(2):273-287
Resource allocation decisions are a fundamental class of problems common throughout a business and therefore are found throughout business school curricula. Entrepreneurs must allocate capital, financiers must allocation cash, and production managers must create the best mix of multiple‐use resources. Within this context, a business school's curriculum, instructional materials, and learning processes must consider the implications of individual decision making. Our traditional instructional content and delivery methods may effectively teach how to set up a decision “problem” and how to obtain an optimal answer. Yet, we may not be teaching a key underlying factor: that entrepreneurs, managers, and future leaders appear to have implicit cognitive biases, which discount information and skew individual decision making. The results of this study demonstrate that a phenomenon known as the “illusion of control” presents a fundamental challenge to the efficacy of formalized educational programs on decision making. TradeSmith was designed as a problem‐based learning exercise to elicit for the illusion of control in a basic, resource allocation, decision environment. The subjects in this study demonstrate a decision‐making pattern consistent with the “illusion of control” phenomenon. Finally, by revealing individuals' implicit design‐making paradigms, TradeSmith helps them experience key issues for managerial decision making. 相似文献
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Jason Paul Howarth Steven D’Alessandro Lester Johnson Lesley White 《International Journal of Lifelong Education》2016,35(1):74-85
Despite the widespread adoption of Massive Open Online Courses (MOOCs), no business model has emerged to make them sustainable from an institution standpoint. Using MOOCs as a marketing platform shows promise; but for this to succeed, it is necessary to understand the motivations of those who undertake them and to demonstrate how these same motivations can be better satisfied through enrolment in a fee-paying university course. We discuss the motivations for students as they progress through a MOOC and the factors that might lead to subsequent university enrolment. Our arguments are informed by MOOC statistics, the AIDA (attention, interest, desire, action) marketing model, and the literature on adult education, technology adoption, goal seeking and consumer value. We argue that most students are led to MOOC enrolment through close alignment of the course topic and subject matter with their personal goals and through the establishment of an attractive value proposition. Progress in the MOOC depends on whether this goal alignment is maintained, and whether the value assumptions of students are met or exceeded. We predict that subsequent university enrolment will most likely occur when the MOOC experience is both satisfying and representative of the university experience, and where the increased time and financial commitment demanded by formal study is offset by the greater likelihood of attaining the focal goal. For this strategy to succeed, it will be necessary for the host institution to actively work with MOOC students to create an awareness of appropriate fee-paying courses and to promote the benefits of university study. This has implications for the way institutions market their courses to MOOC students. 相似文献