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61.
This paper discusses a new algebraic model of electrical networks by which a deeper understanding is achieved of the interrelation existing between a system of independent cut sets and the corresponding system of independent “contours”, in the sense of orthogonal network theory (1).The new model allows, by a redefinition of f-cut sets, to give an interpretation in terms of linear graph theory to the inverse connection matrix A.sb, i.e. to the transformation matrix between voltages in the orthogonal and the primitive reference frames, for a general choice of independent contours.Furthermore, a directly algebraic derivation of the voltage transformation is presented, recalling the properties of dual vector spaces and without invoking the principle of invariance of the instantaneous power.  相似文献   
62.
This paper proposes a novel query expansion method to improve accuracy of text retrieval systems. Our method makes use of a minimal relevance feedback to expand the initial query with a structured representation composed of weighted pairs of words. Such a structure is obtained from the relevance feedback through a method for pairs of words selection based on the Probabilistic Topic Model. We compared our method with other baseline query expansion schemes and methods. Evaluations performed on TREC-8 demonstrated the effectiveness of the proposed method with respect to the baseline.  相似文献   
63.
Education and Information Technologies - Integrating computer science (CS) into school curricula has become a worldwide preoccupation. Therefore, we present a CS and Robotics integration model and...  相似文献   
64.
This paper elaborates a view on knowledge as a result of a combinatorial search activity, so as to investigate its effects on economic growth at the regional level. Empirical estimations corroborate the hypothesis that knowledge coherence and variety, besides the traditional measure of knowledge stock, matter in shaping regional economic performances. The check for spatial dependence suggests that cross-regional externalities exert additional triggering effects on growth, without debasing the effects of knowledge properties. Important policy implications stem from the analysis, in that regional innovation strategies should be carefully coordinated so as to reach a higher degree of internal coherence and trigger economic performances.  相似文献   
65.
A historical case study concerning the serious doubts that arose in early 1930s about the validity of the law of energy conservation in nuclear disintegrations, and the hypothesis of neutrino, will be closely analyzed with the goal of promoting understanding of the nature of science. This work is based upon primary archival and printed sources, with a particular focus on the proceedings of the first International Conference of Nuclear Physics which was held in Rome on October 1931.  相似文献   
66.
The Consortium for Distance University was founded in 1984 to set up a distance teaching university system in Italy. Its activity started in 1986 with the foundation of the Special Purpose School of Information Technology based on distance teaching methods. In 1991 a university diploma was established according to the European educational system. The 3‐year programme includes 28 learning modules and a final apprenticeship. The modules have been developed through a number of learning units, in the form of printed materials and computer‐aided instruction packages that enable learners to organize their own learning autonomously. Assistance to learners takes place in study centres where students meet tutors and use the hardware equipment needed for the software materials. In the academic year 1994/95, an experimental delivery of the university diploma in information technology through the CMC technologies will begin at some Italian universities so that it will be possible to demonstrate how the new modern technologies help students to manage their learning process in real time.  相似文献   
67.
This article critically assesses the policy orientation, social impacts, and linkages of telecommunications in the United States within a government deregulated policy environment and an increasingly globalized economy. Deregulation has been driven by both ideological and technological demands, stemming from several political and economic transformations in the world economy, the collapse of state socialism in eastern Europe and the former Soviet Union, and greater oligopolistic competition among transnational corporations. An expanded infrastructure of new digital information and communications technology (ICT) is the foundation of a worldwide political economic regime of accumulation. ICT increases command and control capabilities of large corporations, together with the mobility and liquidity of capital, making it essential to the restructuring of the world economy, the new international division of labor, and the creation of global "information city" networks. At the same time, government deregulation and rapid technological change are associated with a number of spatial, economic, and social dualisms.  相似文献   
68.
At the end of 2019, the Covid-19 pandemic spread caused restrictions in business and social spheres. Higher education was also severely affected: universities and medical schools moved online to distance learning and laboratory facilities closed. Questions arise about the long-term effects of this pandemic on anatomical education. In this systematic review, the authors investigated whether or not anatomical educators were able to deliver anatomical knowledge during this pandemic. They also discuss the challenges that anatomical education has faced over the last year. The search strategy was conducted between July 2020 and July 2021. Two hundred and one records were identified, and a total of 79 studies were finally included. How best to deliver anatomy to students remains a moot point. In the last years, the advent of new technologies has raised the question of the possible overcoming of dissection as the main instrument in anatomical education. The Covid-19 pandemic further sharpened the debate. Remote learning enhanced the use of technologies other than cadaveric dissection to teach anatomy. Moreover, from the analyzed records it appears that both from students' perspective as well as teachers' there is a clear tear between those who endorse dissection and those who believe it could be easily overcome or at least integrated by virtual reality and online learning. The authors strongly believe that the best anatomy teaching practice requires the careful adaptation of resources and methods. Nevertheless, they support cadaveric dissection and hope that it will not be replaced entirely as a result of this pandemic.  相似文献   
69.

In this paper, we examine the attitudes toward integrating work and family in a sample of 247 teachers in Switzerland and Israel. More particularly, we focus on the national context’s role in mediating the relations between professional and private spheres. The data were collected by a questionnaire implemented and administered in the two countries. The analysis reveals differences between Israeli and Swiss teachers regarding the importance of attribution to life roles and their attitudes toward conflict and facilitation. Findings suggest new insights into the consideration of cultural elements in shaping the teachers’ attitudes toward the integration of family and work.

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70.
The cross-linking processes of three drying oils (poppy, linseed, walnut), a class of organic compounds very important in the field of artworks, were studied by means of 1H-NMR spectroscopy, following the change of the protons signals when oils are heated at 60 °C in the presence of air or nitrogen gas. This preliminary information is particularly important to identify the presence of drying oils within a solid painting film. We demonstrated that it was possible to study these films by swollen-state NMR, an innovative spectroscopy method that can directly analyze very small semisolid samples instead of solutions. The main advantages of this method are the short time of analysis, the possibility to analyze samples without any preliminary treatment, and the small quantity of the sample required. Therefore, swollen-state NMR technique was used to characterize three real painting films: in this way, we succeeded in recognizing in real paintings specimens the presence of drying oils employed as binders, avoiding any interferences due to other organic compounds acting as binding agents, like waxes or egg-yolk media.  相似文献   
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