排序方式： 共有65条查询结果，搜索用时 31 毫秒
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Massimo Franceschet 《Journal of Informetrics》2010,4(3):239-248
We performed a thorough comparison of four main indicators of journal influence, namely 2-year impact factor, 5-year impact factor, eigenfactor and article influence. These indicators have been recently added by Thomson Reuters to the Journal Citation Reports, in both science and social science editions, and are thus available for study and comparison over a sample of significative size. We find that the distribution associated with the eigenfactor largely differs from the distribution of the other surveyed measures in terms of deviation from the mean, concentration, entropy, and skewness. Moreover, it is the one that best fits to the lognormal theoretical model. Surprisingly, the eigenfactor is also the most variable indicator when computed across different fields of science and social science, while article influence is the most stable in this respect, and hence the most suitable metric to be used interdisciplinarily. Finally, the journal rankings provided by impact factors and article influence are relatively similar and diverge from the one produced by eigenfactor, which is closer to that given by the total number of received citations. 相似文献
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Using information on 31 in-depth cases of individual M&A deals, we show that technological and market-relatedness between M&A partners distinctly affects the inputs, outputs, performance and organisational structure of the R&D process. While the findings in the literature on the effect of M&A on R&D are quite mixed, we can sharpen results by analysing data at the level of the R&D process. This comes at the price of a smaller sample and more qualitative data, for which caution in the interpretation is necessary. M&A between partners with ex-ante complementary technologies result in more active R&D performers after the M&A. In sharp contrast, when merged entities are technologically substitutive, they significantly decrease their R&D level after the M&A. Moreover, R&D efficiency increases more prominently when merged entities are technologically complementary than when they are substitutive. These two findings on the R&D level and the performance support the scope economy effect of M&A, on the one hand, and reject the scale economy effect of M&A, on the other. Next, for cases in which partners were active in the same technological fields before the M&A, the reduction of R&D is more prominent, while the R&D efficiency gain is smaller if merged entities were rivals in the product market prior to their merger than if they were non-rival. This suggests that rival firms reap little technology gains from mergers. 相似文献
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Massimo Santinello Alessio Vieno Roberto De Vogli 《European Journal of Psychology of Education - EJPE》2011,26(2):235-246
The principal aim of the study is to examine the role of perceived teacher unfairness in predicting bullying behaviour. Data
were taken from the “Health Behaviour in School Aged Children” project, a cross-sectional survey investigating health behaviours
among early adolescents in selected European countries. Bullying behaviour (bully, victim, and bully/victim), perceived teacher
unfairness and others confounding factors were measured through a self-administered questionnaire filled out by a representative
sample of 4,386 (48.4% males) Italian students (11, 13, and 15 years old). Covariates included demographic characteristics,
socioeconomic status, school performance and other psychological factors. After adjusting for age and gender, teacher unfairness
showed a significant association with being a bully (OR = 1.59; CI = 1.40–1.80) and a bully or victim (OR = 1.47; CI = 1.21–1.78).
This relationship remained significant after additional adjustment for several potential confounding factors. Results show
that characteristics of the school setting such as teacher unfairness can be significant predictors of involvement in bullying
behaviour among early adolescents. 相似文献
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Genes are often described by biologists using metaphors derived from computational science: they are thought of as carriers of information, as being the equivalent of ??blueprints?? for the construction of organisms. Likewise, cells are often characterized as ??factories?? and organisms themselves become analogous to machines. Accordingly, when the human genome project was initially announced, the promise was that we would soon know how a human being is made, just as we know how to make airplanes and buildings. Importantly, modern proponents of Intelligent Design, the latest version of creationism, have exploited biologists?? use of the language of information and blueprints to make their spurious case, based on pseudoscientific concepts such as ??irreducible complexity?? and on flawed analogies between living cells and mechanical factories. However, the living organism = machine analogy was criticized already by David Hume in his Dialogues Concerning Natural Religion. In line with Hume??s criticism, over the past several years a more nuanced and accurate understanding of what genes are and how they operate has emerged, ironically in part from the work of computational scientists who take biology, and in particular developmental biology, more seriously than some biologists seem to do. In this article we connect Hume??s original criticism of the living organism = machine analogy with the modern ID movement, and illustrate how the use of misleading and outdated metaphors in science can play into the hands of pseudoscientists. Thus, we argue that dropping the blueprint and similar metaphors will improve both the science of biology and its understanding by the general public. 相似文献
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Francesco Colace Massimo De Santo Luca Greco Paolo Napoletano 《Information processing & management》2015
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
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This article is based on semistructured interviews with library staff members in order to explore both how they perceive the role of libraries in most deprived areas in Newcastle upon Tyne and how they relate with their patrons. We show that public libraries play a primary role in activating a virtuous cycle, in which infrastructures, skills, and increased ability of users to achieve their goals simultaneously result from and feed social inclusion strategies. However, some limits might be related to the availability of public economic resources that tends to affect the smaller libraries by reducing opening times and services provided. 相似文献
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Matteo Zago Marina Codari Massimo Grilli Giuseppe Bellistri Nicola Lovecchio 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(2):234-244
We explored the biomechanics of the 180° change-of-direction with the ball (half-turn) in soccer. We aimed at identifying movement strategies which enhance the players’ half-turning performance, by characterising technique kinematics and understanding the structure of biomechanical and anthropometrics variables. Ten Under-13 sub-elite male players were recorded with an optoelectronic motion analyser while performing a 5-m straight dribbling followed by a half-turn with the sole. Joints kinematics differences between faster and slower trials were found in support-side hip rotation, driving-side hip adduction, trunk flexion and rotation, and arms abduction. To unveil the data-set structure, a principal component (PC) analysis and a stepwise linear discriminant analysis were performed using 30 biomechanical parameters and four anthropometric variables for each trial. Seven retained PCs explained 79% of the overall variability, featuring combinations of original variables that help in understanding the factors facilitating fast half-turns: keeping short steps, minimising lateral and forward body movements, and centre-of-mass lowering, even with ample lower limbs ranges of motion (RoM); abducting the upper limbs while limiting trunk flexion and pelvic inclination RoM. Balance and task-constrained exercises may be proposed to improve this technique. Moreover, a quantitative knowledge of the movement structure could give coaches objective insights to better instruct young players. 相似文献
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Julin Mejía Morales Bjrn Hammarstrm Gian Luca Lippi Massimo Vassalli Peter Glynne-Jones 《Biomicrofluidics》2021,15(1)
A low-cost device for registration-free quantitative phase microscopy (QPM) based on the transport of intensity equation of cells in continuous flow is presented. The method uses acoustic focusing to align cells into a single plane where all cells move at a constant speed. The acoustic focusing plane is tilted with respect to the microscope’s focal plane in order to obtain cell images at multiple focal positions. As the cells are displaced at constant speed, phase maps can be generated without the need to segment and register individual objects. The proposed inclined geometry allows for the acquisition of a vertical stack without the need for any moving part, and it enables a cost-effective and robust implementation of QPM. The suitability of the solution for biological imaging is tested on blood samples, demonstrating the ability to recover the phase map of single red blood cells flowing through the microchip. 相似文献