122,266 research outputs found
Oceanica o quinta parte del mondo [cartographic material] /
No full textMap of Oceania showing Australia, New Zealand, New Guinea and Borneo in particular. A description of "quinta parte del mondo" is provided beneath a scene featuring palm trees, a kangaroo, shelters and canoeists. Acknowledgements to Krusenstern, Kotzebue, Bellinghausen (i.e. Bellingshausen, Bellinsgauzen), King, Freycinet and Duperrei provided in a "Nota". Relief shown by hachures.; Prime meridian: Paris.; Top right-hand corner: Grande Atlante universale no. 7.; Plate no. 7 from: Grande atlante universale di geografia moderna seconda i principj di Malte-Brun. Milano : Stucchi, 1830?; Lower right-hand corner: Milano presso l'incisore Stucchi Contr. di S. Vicenzino N. 2337.; Lower left-hand corner: Torino presso Gio Batta Maggi negoz di Stampe di S. A. il Prin. di Carignano contre di Po.; Tooley, 1213.; Also available in an electronic version via the Internet at: http://nla.gov.au/nla.map-t1213. Inset: Detagli di una parte della nuova Galles Meridionale. Relief shown by hachures
Noi, Enea: ritrovamenti virgiliani nella poesia di Caproni
No full textIl saggio di Silvia Stucchi cerca di indagare la presenza di Virgilio, e, nello specifico, della figura di Enea impegnato nel suo viaggio agli Inferi nell'ambito della poesia di Giorgio Caproni, in particolare nelle "Stanze della funicolare"
Chebyshev array forming for near surface investigations
No full textIn recent years, reflection seismics has increasingly been extended to near surface investigations to help in better delineate the subsurface properties, in particular the shallow layers geometry. The applications of shallow reflection surveys range from hydrogeological prospecting (Pugin et al., 2009; Ge et al., 2010), environmental and engineering problems (Miller and Steeples, 1994; Shtivelman, 2003), landslide characterization (Malemhir et al., 2013; Stucchi et al., in press) to mention but just a few.
The generally limited availability of recording hardware when compared to oil or mining exploration, and the often poor performance of the energy sources, are two problems that add to the known difficulties inherent to the near surface exploration (Steeples and Miller, 1998). It is quite common to employ recording equipment using only 24 or 48 active channels, with single vertical or horizontal geophone (for P- or S-wave survey), and simple energy sources such as the sledgehammer or the weight drop. This results in a poor depth penetration of the seismic signal and in a severe source related noise contamination (ground roll and air blast) of the acquired data. However, it may be possible to turn these hardware weaknesses into potential advantages. In fact, the relative facility of striking blows with the sledgehammer and the flexibility aptitude of 24-48 channel short spreads allow the geophysicist to acquire a plentiful quantity of data and to leave to the processing lab the task to appropriately stack them to increase the signal-to-noise (S/N) ratio. This corresponds to performing source and/or receiver array simulations, where the output can be optimized on the basis of specific criteria such as noise attenuation or resolution. Indeed, contrarily to what happens in the field where the arrays would be fixed along the entire profile, the simulation of arrays in the processing can be time and space variant and their responses can be changed according to the changing characteristics of the data.
In our work we demonstrate how effective spatial filters can be easily obtained by properly mixing and weighting different traces and how this turns out in a fair improvement in the data quality. The optimal weights are computed by means of Chebyshev polynomials (Carlini and Mazzotti, 1989; Holzman, 1963), where “optimal” is intended as more efficient and uniform noise attenuation in the array filter stop-band region compared to the un-weighted array. The real data pertain to a reflection survey carried out to delineate the subsurface structure of a huge landslide located in the Northern Apennine, Italy (Stucchi et al., in press). A 10 kg sledgehammer and a 48 channels single geophone spread were used as the energy source and the recording devices in the production phase
Suggestions for interdisciplinary teaching in mathematics education: The case of the history of the concept of group
No full textThe role of the history of mathematics in mathematics education, as a support in teaching, is widely acknowledged. It can serve to arouse students’ interest in mathematics as well as to stimulate reflection on mathematical concepts and methods. This work focuses on the group as “cross-concept”, in relation to its history from its origins in algebra to its applications in other areas. Given its very nature, the group should be adequately re-evaluated in an interdisciplinary approach, which may prove particularly captivating in linking the history of mathematics to the history of the psychology of perception. This historical interdisciplinary perspective may be useful in the context of university mathematics teaching, particularly teacher training
S/N enhancement by means of array simulation for near surface seismic investigations
No full textWe present a procedure for enhancing the signal-to-noise ratio (S/N) of shallow seismic reflection data based on two different steps: 1) an acquisition step that requires the recording of closely spaced common source records with standard source and receiver equipment and 2) a processing step where weighted or un-weighted source and receiver arrays are simulated on the basis of required needs for source related noise attenuation and depth penetration. The data acquisition can be carried out employing single source-single geophone recordings, with a standard 24 or 48-channel equipment. Simple energy sources such as weight drop or sledgehammer are considered. The design and application of the spatial filters in the processing phase is very flexible and can be tailored to the specific needs. In fact, the simulated source and/or receiver arrays can be time and/or space variant and can be weighted to provide the desired responses. Optimal weights can be determined by means of Chebyshev polynomials. Real data examples show the increase in the data quality in terms of better coherent noise attenuation and of enhanced depth penetration
Repulsive Serial Effects in Visual Numerosity Judgments
No full textWe investigated how the approximate perceived numerosity of ensembles of visual elements is modulated by the numerosity of previously viewed ensembles depending on whether the first ensemble is held in visual working memory or not. We show that the numerosity of the previously seen ensemble has a repulsive effect, that is, a stimulus with high numerosity induces an underestimation of the following one and vice versa. This repulsive effect is present regardless of whether the first stimulus is memorized or not. While subtle changes of the experimental paradigm can have major consequences for the nature of interstimulus dependencies in perception, generally speaking the fact that we found such effects in a visual numerosity estimation task confirms that the process by which human observers produce estimates of the number of elements bears analogies to the processes that lead to the perception of visual dimensions such as orientation
Il latino è vivo e lotta con noi e per noi
No full textL'articolo presenta una recensione del saggio di N. Gardini, "Viva il latino. Storia e bellezza di una lingua inutile"; Garzanti 2016, discutendo la presunta "inutilità" dello studio dei classici, e affrontando in prospettiva storica, didattica ed estetica il problema della difesa degli studi umanistici
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