An Intuitive Physics Study on the Role of Mass in Horizontal Collisions

The participants in our experiment were asked to judge whether simulated horizontal collisions appeared to be “natural” or “unnatural”. We manipulated the simulated materials and the velocity ratio of two colliding objects. The results revealed a fair degree of consistency between predictions of Newtonian mechanics and the participants’ responses

Image processing and analysis of radar and lidar data: new discoveries in Verona southern lowland (Italy)

ABSTRACTThis contribution proposes an evaluation of lidar and radar data processing and its potential in revealing archaeological features within a level plain environment, the southern lowland of Verona (Italy), focusing on evidences dating back to the Bronze Age. Many archaeological sites in the research area, including some of the most outstanding settlements of Terramare Culture, were identified or at least examined through aerial photo observation. Even if in several occasions modern agricultural activities contributed to the discoveries, bringing to the surface artifacts and scrapes of buried layers, this kind of impact has also been progressively deteriorating the archaeological record, hence the proto-historic landscape is now discernible through evanescent marks which cannot be always detected using customary optical sensors. Lidar and radar data analysis has then been considered as an alternative, non-invasive method of investigation on such a vast area

"Invariants" in Koffka's Theory of Constancies in Vision: Highlighting Their Logical Structure and Lasting Value

Summary By introducing the concept of "invariants", Koffka (1935) endowed perceptual psychology with a flexible theoretical tool, which is suitable for representing vision situations in which a definite part of the stimulus pattern is relevant but not sufficient to determine a corresponding part of the perceived scene. He characterised his "invariance principle" as a principle conclusively breaking free from the "old constancy hypothesis", which rigidly surmised point-to-point relations between stimulus and perceptual properties. In this paper, we explain the basic terms and assumptions implicit in Koffka's concept, by representing them in a set-theoretic framework. Then, we highlight various aspects and implications of the concept in terms of answers to six separate questions: forms of invariants, heuristic paths to them, what is invariant in an invariant, roots of conditional indeterminacy, variability vs. indeterminacy, and overcoming of the indeterminacy. Lastly, we illustrate the lasting value and theoretical power of the concept, by showing that Koffka's insights relating to it do occur in modern perceptual psychology and by highlighting its role in a model of perceptual transparency

Représentations en arbre de proximités relatives

Sur une famille d’ensembles, une relation ternaire peut être définie en convenant que, pour U, V, W membres de la famille, V est considéré comme « interposé » entre U et W au cas où V inclurait l’intersection entre U et W . Cette relation est dénommée « interposition selon intersection » et elle peut être interprétée comme la description des rapports de proximité entre objets associés aux ensembles dans la famille. L’éventuel usage d’un graphe en arbre pour la représentation d’une telle relation est examiné. Des caractérisations sont démontrées aussi bien pour une représentation pleine (il existe un arbre dont l’interposition coïncide avec l’interposition selon intersection donnée : Section 2), que pour une représentation partielle (il existe un arbre dont l’interposition est incluse dans l’interposition selon intersection donnée : Section 3). Dans la Section 4 sont illustrées des procédures servant à la construction effective de solutions du problème de représentation, pleine et partielle. Dans la Section 5 sont rappelés certains paradigmes de la psychométrie moderne afin de mettre en évidence les particularités de la méthode proposée.On a family of sets, a ternary relation may be defined by stating that, for U, V, W members of the family, V is “between” U and W if and only if V includes the intersection of U and W. The relation is called “intersection-betweenness” and may be understood as the description of proximities between objects associated with sets in the family. The problem of using a tree graph for representing such a relation is discussed. Characterisations are proven both for full tree representation (there is a tree-betweenness identical to the given intersection-betweenness: Section 2) and for partial tree representation (there is a tree-betweenness included in the given intersection-betweenness: Section 3). Procedures for actually finding solutions to full and partial tree representation problems are illustrated in Section 4. In Section 5 some related paradigms of modern psychometrics are mentioned, to highlight the peculiar aspects of the proposed approach

Extragalactic Compact Sources in the Planck Sky and Their Cosmological Implications

The Planck satellite has proved to be a very successful mission, which has been operating flawlessly for more than 36 months. Its main purpose is to map the anisotropies of the CMB radiation at 9 frequencies, between 30 and 857 GHz, with unprecedented resolution and sensitivity. After a description of the properties and cosmological aims of Planck, we review the results obtained during the first 1.6 full sky surveys relative to compact extragalactic sources and their implications. The most recent and efficient methods and filters for compact source detection in the presence of Gaussian noise and CMB anisotropies are discussed. The first surveys of Planck have enabled the detection of about 200 galaxy clusters, by the SZ effect, and from several hundreds to many thousands of extragalactic point sources (EPS), presented in the Planck ERCSC. We review the results on the SZ effect in galaxy clusters. We discuss the possibilities of future Planck data to study clusters through the SZ effect and the interesting possibilities of combining these data with X ray observations. These EPS can be classified into two main source classes: radio sources, at intermediate to high z; far IR sources, typically at very z. Planck number counts of EPS at LFI frequencies are in agreement with WMAP counts. A clear steepening of the mean spectral index of bright radio sources is observed above 70 GHz, that can be interpreted in terms of a break frequency in their spectra. For nearby dusty galaxies, Planck observations find evidence of colder dust, with T < 20 K, than has previously been found. More recently, the number counts of bright local dusty galaxies and of synchrotron sources have been measured by Planck at submm wavelengths. Planck has provided interesting results on the angular distribution of CIB anisotropies, allowing us to put new constraints on clustering properties of dusty galaxies at high z.Comment: 30 pages, 12 figures. Abstract absent in the published version. See http://www.intechopen.com/articles/show/title/extragalactic-compact-sources-in-the-planck-sky-and-their-cosmological-implication

PRISM (Polarized Radiation Imaging and Spectroscopy Mission): A White Paper on the Ultimate Polarimetric Spectro-Imaging of the Microwave and Far-Infrared Sky

PRISM (Polarized Radiation Imaging and Spectroscopy Mission) was proposed to ESA in response to the Call for White Papers for the definition of the L2 and L3 Missions in the ESA Science Programme. PRISM would have two instruments: (1) an imager with a 3.5m mirror (cooled to 4K for high performance in the far-infrared---that is, in the Wien part of the CMB blackbody spectrum), and (2) an Fourier Transform Spectrometer (FTS) somewhat like the COBE FIRAS instrument but over three orders of magnitude more sensitive. Highlights of the new science (beyond the obvious target of B-modes from gravity waves generated during inflation) made possible by these two instruments working in tandem include: (1) the ultimate galaxy cluster survey gathering 10e6 clusters extending to large redshift and measuring their peculiar velocities and temperatures (through the kSZ effect and relativistic corrections to the classic y-distortion spectrum, respectively) (2) a detailed investigation into the nature of the cosmic infrared background (CIB) consisting of at present unresolved dusty high-z galaxies, where most of the star formation in the universe took place, (3) searching for distortions from the perfect CMB blackbody spectrum, which will probe a large number of otherwise inaccessible effects (e.g., energy release through decaying dark matter, the primordial power spectrum on very small scales where measurements today are impossible due to erasure from Silk damping and contamination from non-linear cascading of power from larger length scales). These are but a few of the highlights of the new science that will be made possible with PRISM.Comment: 20 pages Late

Planck LFI-only mission extension

The main reason for the extension of the Planck mission beyond the lifetime of the 0.1-K dilution cooler is to obtain further data which will improve our understanding of systematic effects. In the present report, we justify the continuation of the current scanning strategy in order to obtain a sixth survey, allowing for better sensitivity and further “jackknife” (survey difference) tests. The fifth survey is already improving the estimates of the polarisation leakage for two of the LFI horns, and this improvement will continue with the sixth survey during the extension. In addition, we confirm the “deep rings” scanning strategy to improve mapping of the beams using radio sources, specifically Jupiter and the Crab Nebula. We propose to maintain the current spin rate: no other changes are foreseen, except the possibility to increase the sampling of some house-keeping data

Perceptual slant induced through optical contact

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