2,242 research outputs found
Polarization singularities in paraxial vector fields: morphology and statistics
No full textPolarization patterns in the transverse plane generically contain singularities: points of circular polarization (C points), lines of linear polarization (L lines), instantaneous zeros (disclinations) and component zeros. We investigate the geometry of ellipse fields at these singularities, using the Stokes parameters and others to characterize the singular geometry and morphology. Comparison is made with analogous structures on random surfaces, namely umbilic points and parabolic lines. The densities and correlations of the different types of polarization singularities are calculated in random polarization fields, and compared to the statistics of phase singularities and random surfaces
Esperienza ed evento della verità. Pratica filosofica e astrazione scientifica nel pensiero di A.N. Whitehead
No full textThis article analyzes the relationship between philosophy, experience and event in A.N. Whitehead’s thought. From the critics of the concept of object, the author retraces and describes the peculiar “abstract-concrete dialectic”, at the center of the researches concerning the perceptual experience.
Furthermore, according to Whitehead’s later works, she demonstrates how the philosophical practice is different from all other kinds of science, although it requires science itself because of the co-implication of object and event, abstraction and recognition
Il "Guerrin Meschino" di Gesualdo Bufalino : un'"opra" in versi
No full textGesualdo Bufalino first published Il Guerrin Meschino in 1991 in a non-commercial edition. In 1993, after a deep revision, he re-published his work with publisher Bompiani: the novel has a modified plot, and the author decided to insert three new poems in addition to the opening and closing poems, formerly present in 1991’s edition. This paper, in its entirety supported by handwritten material preserved at Fondazione Gesualdo Bufalino (Comiso), is divided in two parts: the first part illustrates the differences between the first and the second edition, the second part provides a critical edition of the five poems
A FEW WORDS ABOUT THE TEACHER. IN MEMORY OF THE EXCELLENT TEACHER AND SCIENTIST M.R. SAPIN
No full textM.R. Sapin (1925–2015) was a professor at I.M. Sechenov First Moscow State Medical University, honorary academician of Russian academy of medical sciences (1988), and an outstanding representative of the Moscow anatomical school of the middle of XX – early XXI century. From the very beginning of his medical training, Mikhail Romanovich got interested in anatomy, especially in angiology and lymphology, and later concentrated on its studying. The author of more than 30 text books and guidelines for schools, universities, and colleges, Mikhail Romanovich was the doctoral and thesis advisor of 51 Ph.D. and approximately 70 MD dissertations. M.R. Sapin made a significant contribution to the development of anatomical education providing the departments with a various range of dry and wet specimens. His stunning and effective work as a tutor was highly appreciated by his students and colleagues, Russian and foreign anatomists. M.R. Sapin was the leader of the Laboratory of Functional Anatomy since 1972, president of the International Association of Morphologists (1992–2006), chairman of the expert commission of Higher Attestation Commission (1959–1994), etc. A man of a great willpower, M.R. Sapin faced a lot of obstacles in his life and research work but overcame that all successfully. The article presents the most important facts of anatomist’s career and lifetime.</jats:p
Phase singularities in isotropic random waves
No full textThe singularities of complex scalar waves are their zeros; these are dislocation lines in space, or points in the plane. For waves in space, and waves in the plane (propagating in two dimensions, or sections of waves propagating in three), we calculate some statistics associated with dislocations for isotropically random Gaussian ensembles, that is, superpositions of plane waves equidistributed in direction but with random phases. The statistics are: mean length of dislocation line per unit volume, and the associated mean density of dislocation points in the plane; eccentricity of the ellipse describing the anisotropic squeezing of phase lines close to dislocation cores; distribution of curvature of dislocation lines in space; distribution of transverse speeds of moving dislocations; and position correlations of pairs of dislocations in the plane, with and without their strength (topological charge) -1. The statistics depend on the frequency spectrum of the waves. We derive results for general spectra, and specialize to monochromatic waves in space and the plane, and black-body radiation
Verslag van het voorgevallene tijdens het hooge opperwater op de Nederlandsche rivieren in den winter van 1919 op 1920
No full textNadat de Rijn op 20 December 1919 tot even beneden den middelbaren zomerstand 1901-1910 (M.R.) was gedaald vertoonde zich op die rivier een sterke en vrij snelle was, waardoor het water te Keulen tot 6m +M.R. bij het einde van het jaar steeg. In de daarop volgende 11 dagen daalde de waterstand tot 1.5m +M.R. om daarna in 5 dagen weder te rijzen tot den zeer hoogen stand van 7m +M.R. Door een aanvankelijk sterken later flauweren val liep de stand weder terug tot 1.5m +M.R. op 30 Januari. Ook op de Maas vertoonden zich twee dicht op elkaar volgende sterke wassen. Bij den aanvang van den eersten was op 19 december stond het water te Maastricht op ruim 1m +M.R. en steeg het in 6 dagen tot 4.37m +M.R.; in de daaropvolgende 9 dagen bleef de stand steeds hoger dan 4m +M.R. en daalde toen tot ongeveer 2m +M.R. op 10 Januari 1920. De tweede was trad op laatsgenoemde datum in waarbij het water oplied tot 4.94m +M.R. op 15 Januari. Het water daalde daarna dadelijk en was op 29 Januari tot ongeveer 2m +M.R. weggevallen. Bij den tweeden was op Rijn en Maas werden de hoogst bekende waterstanden bij open rivieren overtroffen te Keulen met 7 cm en te Maastricht met 2 cm. De rivieren waren ijsvrij.Hoogwaterversla
Correlations and screening of topological charges in Gaussian random fields
No full textTwo-point topological charge correlation functions of several types of geometric singularity in Gaussian random fields are calculated explicitly, using a general scheme: zeros of n-dimensional random vectors, signed by the sign of their Jacobian determinant; critical points (gradient zeros) of real scalars in two dimensions signed by the Hessian; and umbilic points of real scalars in two dimensions, signed by their index. The functions in each case depend on the underlying spatial correlation function of the field. These topological charge correlation functions are found to obey the first Stillinger-Lovett sum rule for ionic fluids
Phase critical point densities in planar isotropic random waves
No full textThe densities of critical points of phase (extrema and saddles), which play an important role in the theory of phase singularities (wave dislocations) in two dimensions, are calculated in isotropic plane wave superpositions. Critical points and dislocations are put on an equal footing as zeros of the two-dimensional current (Poynting vector), and the results, depending only on the second and fourth moments of the wave spectrum (distribution of wavenumbers), are related to the corresponding dislocation density. Explicit results for several spectra are derived, discussed and related to previous results
Seismic prevention and rahabilitation of nonstructural elements. Criteria to define a post-seismic damage analysis procedure
No full textIt reports very briefly the research work, developed by the author during her Doctorate course, about a post-seismic damage analysis procedure for nonstructural elements of framed structure building system
The Ontology of the Causal Basis of Man : To the Theory of Time
No full textIn 2014, Amirbegov Y.M.'s monograph titled "Mechanics of Thinking" or "Ontological Basis of the Subject" was published, which dealt with a philosophical question: the relationship of matter with consciousness and time of our being. But since the monograph duplicated the thesis conceived by the author and did not go beyond the material presented in it, on the advice of the consultant the author of the monograph is preparing its second edition in an expanded version with a new title: " Ontology of Causal Basis of Man", attracting his mentor, the author of "The Theory of Time or Principle of Formation of Matter Forms" Amirbegov M.R., as a co-author of this book,
Adhering to the opinion that matter between past and future temporal conti-nuity of eternity is reduced to nothing and in reality there remains only a causeless "Nothing", the authors of this book from a clean sheet, but with baggage of knowledge about objective forms of being and causeless reality with its possibili-ties, build an unparalleled theoretical model of human integrity, answering the question: what does a man, his sensorium, consciousness, his thinking apparatus and thought itself, why and how? The authors submit this book to the judgment of the reader
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