The Pendulum: From Constrained Fall to the Concept of Potential

Kuhn underlined the relevance of Galileo’s gestalt switch in the interpretation of a swinging body from constrained fall to time metre. But the new interpretation did not eliminate the older one. The constrained fall, both in the motion of pendulums and along inclined planes, led Galileo to the law of free fall. Experimenting with physical pendulums and assuming the impossibility of perpetual motion Huygens obtained a law of conservation of vis viva at specific positions, beautifully commented by Mach. Daniel Bernoulli generalised Huygens results introducing the concept of potential and the related independence of the ‘work’ done from the trajectories (paths) followed: vis viva conservation at specific positions is now linked with the potential. Feynman’s modern way of teaching the subject shows striking similarities with Bernoulli’s approach. A number of animations and simulations can help to visualise and teach some of the pendulum’s interpretations related to what we now see as instances of energy conservation.     

Learning from students,inquiry into practice,and participation in professional communities: Beginning teachers' uneven progress toward equitable science teaching

In this research project, we investigated two beginning secondary science teachers' efforts to learn to teach science in ways that build from and celebrate the ethnic, gender, linguistic, and academic diversity of their students. To do so, we followed Troy and Brian from their preservice teacher education experiences through their first year of teaching 8th grade physical science at local junior high schools. We also conducted a follow‐up observation and interview with each participant after he had moved past the beginning stage of survival in the teaching profession—once in his fourth year of public school science teaching. Through qualitative analysis of interviews, classroom observations, and teachers' written work, we identified patterns and explored commonalities and differences in Troy and Brian's views and practices tied to equity over time. In particular, we examined successes and challenges they encountered in learning to teach science for all (a) from their students, (b) from inquiry into practice, and (c) from participation in professional communities. In our implications, we suggest ways teacher educators and induction professionals can better support beginning teachers in learning to teach science to all students. In particular, we highlight the central roles both individual colleagues and collective school cultures play in aiding or impeding beginning teachers' efforts to learn from students, from practice, and from professional communities. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 44: 586–612, 2007.     

Environmental education research in Brazil: some highlights from theses and dissertations

Abstract

This article discusses an analysis of abstracts of Brazilian theses and dissertations on environmental education from a database organised and maintained by a group of researchers in the EArt Project (www.earte.net). In presenting extracts of key trends in this dataset, our aim is to provide a snapshot of the many possible approaches to, and histories of, Brazilian environmental education research. The data also allow us to raise some questions that explore possible ‘blank spots’, ‘blind spots’ and ‘bald spots’ in Brazilian research on environmental education. Given the temporal development of the research field since the 1980s, we illustrate these ‘spots’ by exploring data related to epistemological and methodological diversity, from the viewpoint of knowledge areas as well as the graduate programmes that have been developing research on environmental education. Finally, we draw a picture of the methodological trends that have been privileged by Brazilian researchers, and pose questions as to what is needed in shaping an agenda for research on environmental education in Brazil into the future.     

e-university: a cross-case study in four Italian universities

This paper describes the aims, the methods, the stages and the results of the research project 'e-University. Information and communication technologies (ICTs) as a factor of change in Italian universities', undertaken between 2003 and 2006 by the Universities of Trento, Perugia and Sassari and the Catholic University of Milan.
The characteristics of the four institutions' subjects and objects of the investigation are analysed as case studies and then compared as a cross-case study in the light of the factors that we feel constitute the main areas of concern in the four institutions as to the implementation of ICTs in the teaching/learning process, ie, the characteristics of the governance strategic plan, the choices relating to technology and the choices related to pedagogy. The paper describes the collaborative effort characterising the community of researchers through the different stages of the research. It also analyses how the individual features of each university—relating to its history, the number of students, the range of faculties, the diffusion of e-learning, the driving factors for innovation, the institution's policies—have fostered a lively and fruitful discussion between different view points, thus engendering deeper reflections for each context.     

A Characterisation Study on Modern Bronze Sculpture: The Artistic Patinas of Nado Canuti

Artistic patination is a traditional colouring technique for metal sculpture, employed by artists in ancient and modern times for aesthetic purposes. Today, knowledge of the artistic value and the chemistry of this superficial chromatic layer, called ‘artistic patina’, can be successfully acquired through a close collaboration between living artists, foundry artisans, and scientists. Starting from several interviews with the Italian artist Nado Canuti and foundry artisans, specific information was gathered about patination methods and the artist’s attitude towards materials restoration. Afterwards, the patinas most used by Canuti were reproduced to study their nature before any ageing or degradation. Their chromatic values, morphologies, and compositions were studied employing a range of techniques such as colour measurements, scanning electron microscopy with energy dispersive X-ray spectroscopy, and micro-Raman spectroscopy. The collected data revealed the formation of main compounds (cuprite, cassiterite, rouaite, chalcocite, isocubanite, and ferroxyhite) and additional compounds (atacamite and CN-containing compound). The scientific results, as well as the artist’s statements concerning the patinas’ significance, maintenance, and conservation, will contribute towards the future care and preservation of Canuti’s sculptures.     

Biorthogonal wavelet trees in the classification of embedded signal classes for intelligent sensors using machine learning applications

The paper deals with a method of constructing orthonormal bases of coordinates which maximize, through redundant dictionaries (frames) of biorthogonal bases, a class separability index or distances among classes. The method proposes an algorithm which consists of biorthogonal expansions over two redundant dictionaries. Embedded classes are often present in multiclassification problems. It is shown how the biorthogonality of the expansion can really help to construct a coordinate system which characterizes the classes. The algorithm is created for training wavelet networks in order to provide an efficient coordinate system maximizing the Cross Entropy function between two complementary classes. Sine and cosine wavelet packets are basis functions of the network. Thanks to their packet structure, once selected the depth of the tree, an adaptive number of basis functions is automatically chosen. The algorithm is also able to carry out centering and dilation of the basis functions in an adaptive way. The algorithm works with a preliminary extracted feature through shrinkage technique in order to reduce the dimensionality of the problem. In particular, our attention is pointed out for time-frequency monitoring, detection and classification of transients in rail vehicle systems and the outlier problem. In the former case the goal is to distinguish transients as inrush current and no inrush current and a further distinction between the two complementary classes: dangerous inrush current and no dangerous inrush current. The proposed algorithm is used on line in order to recognize the dangerous transients in real time and thus shut-down the vehicle. The algorithm can also be used in a general application of the outlier detection. A similar structure is used in developed algorithms which are currently integrated in the inferential modeling platform of the unit responsible for Advanced Control and Simulation Solutions within ABB's (Asea Brown Boveri) industry division. It is shown how impressive and rapid performances are achieved with a limited number of wavelets and few iterations. Real applications using real measured data are included to illustrate and analyze the effectiveness of the proposed method.     

Self-citations as strategic response to the use of metrics for career decisions

There is limited knowledge on the extent to which scientists may strategically respond to metrics by adopting questionable practices, namely practices that challenge the scientific ethos, and the individual and contextual factors that affect their likelihood. This article aims to fill these gaps by studying the opportunistic use of self-citations, i.e. citations of one’s own work to boost metric scores. Based on sociological and economic literature exploring the factors driving scientists’ behaviour, we develop hypotheses on the predictors of strategic increase in self-citations. We test the hypotheses in the Italian Higher Education system, where promotion to professorial positions is regulated by a national habilitation procedure that considers the number of publications and citations received. The sample includes 886 scientists from four of science’s main disciplinary sectors, employs different metrics approaches, and covers an observation period beginning in 2002 and ending in 2014. We find that the introduction of a regulation that links the possibility of career advancement to the number of citations received is related to a strong and significant increase in self-citations among scientists who can benefit the most from increasing citations, namely assistant professors, associate professors and relatively less cited scientists, and in particular among social scientists. Our findings suggest that while metrics are introduced to spur virtuous behaviours, when not properly designed they favour the usage of questionable practices.     

The contribution of urban-scale environmental monitoring to materials diagnostics: A study on the Cathedral of Modena (Italy)

The problem of environmental monitoring aimed at identifying and evaluating the weathering mechanisms affecting historical stoneworks is here discussed and a methodology based on the use of already available, long record, urban-scale environmental data is proposed. An example of its application to the Cathedral of Modena (Italy, XII-XIV century, included in the UNESCO's World Heritage List) is then presented. In this case, the methodology allowed the identification of the main degradation causes, which found significant confirmation by material diagnostics on the available samples and finite element structural modelling. Thanks to the decay causes identification allowed by the proposed methodology, more effective restoration procedures can be outlined.