677 research outputs found
Jednostka jako podmiot badań pedagogicznych i społecznych
Metoda indywidualnych przypadków jest sposobem badań, polegającym na analizie jednostkowych losów
ludzkich, uwikłanych w określone sytuacje wychowawcze, lub na analizie konkretnych zjawisk natury
wychowawczej, poprzez pryzmat jednostkowych biografii ludzkich, z nastawieniem na opracowanie diagnozy
przypadku lub zjawiska w celu podjęcia działań terapeutycznych.
Z potrzeby rozpoznania skomplikowanych sytuacji, ich istoty i przyczyn zrodziła się metoda, która
wkomponowana została w praktyczne cele usuwania nieprawidłowości lub sytuacji zagrożenia w
indywidualnych losach ludzkich. Jej szczególny rodowód i ścisłe pokrewieństwo z metodą pracy socjalnej
uzasadniają uwarunkowania społeczne funkcjonowania jednostki, przewidywany efekt oddziaływań
terapeutycznych i prognozowanie zmian.
Pod pojęciem ''przypadku'' rozumie się różne jednostki, żyjące i działające w określonych środowiskach
społecznych, wyróżniające się od innych, od swoich rówieśników na przykład, jeśli chodzi o uczniów w szkole,
czy dzieci w przedszkolu. Odbieganie od normy, nie jest traktowana jako wada, ponieważ pojedynczy przypadek,
badacz (także pedagog, nauczyciel) osadza w znanej sobie teorii, a opis przypadku, który nie znajduje swego
odzwierciedlenia w teorii, może przyczynić się do jej wzbogacenia, a nawet przekształcenia
Influence of Dy doping on the properties of BiFeO3
The aim of this research was to fabricate and study the properties of Bi1-x DyxFeO3 (for x = 0, 0.05, 0.07, 0.1) ceramics
materials. Simple oxide powders Bi2O3, Dy2O3 and Fe2O3 were used to fabricate Bi1-xDyxFeO3 ceramics by mixed oxide method
followed by free sintering. The study presents changes in microstructure and crystal structure as well as in dielectric properties and
magnetic properties caused by modification of BiFeO3 with dysprosium dopant
Simulation of FRET dyes allows quantitative comparison against experimental data
Fully understanding biomolecular function requires detailed insight into the systems’ structural dynamics. Powerful experimental techniques such as single molecule Förster Resonance Energy Transfer (FRET) provide access to such dynamic information yet have to be carefully interpreted. Molecular simulations can complement these experiments but typically face limits in accessing slow time scales and large or unstructured systems. Here, we introduce a coarse-grained simulation technique that tackles these challenges. While requiring only few parameters, we maintain full protein flexibility and include all heavy atoms of proteins, linkers, and dyes. We are able to sufficiently reduce computational demands to simulate large or heterogeneous structural dynamics and ensembles on slow time scales found in, e.g., protein folding. The simulations allow for calculating FRET efficiencies which quantitatively agree with experimentally determined values. By providing atomically resolved trajectories, this work supports the planning and microscopic interpretation of experiments. Overall, these results highlight how simulations and experiments can complement each other leading to new insights into biomolecular dynamics and function
Simulations of COMPASS vertical displacement events with a self-consistent model for halo currents including neutrals and sheath boundary conditions
The understanding of the halo current properties during disruptions is key to design and operate large scale tokamaks in view of the large thermal and electromagnetic loads that they entail. For the first time, we present a fully self-consistent model for halo current simulations including neutral particles and sheath boundary conditions. The model is used to simulate vertical displacement events (VDEs) occurring in the COMPASS tokamak. Recent COMPASS experiments have shown that the parallel halo current density at the plasma-wall interface is limited by the ion saturation current during VDE-induced disruptions. We show that usual magneto-hydrodynamic boundary conditions can lead to the violation of this physical limit and we implement this current density limitation through a boundary condition for the electrostatic potential. Sheath boundary conditions for the density, the heat flux, the parallel velocity and a realistic parameter choice (e.g. Spitzer's resistivity and Spitzer-Harm parallel thermal conductivity) extend present VDE simulations beyond the state of the art. Experimental measurements of the current density, temperature and heat flux profiles at the COMPASS divertor are compared with the results obtained from axisymmetric simulations. Since the ion saturation current density (Jsat) is shown to be essential to determine the halo current profile, parametric scans are performed to study its dependence on different quantities such as the plasma resistivity and the particle and heat diffusion coefficients. In this respect, the plasma resistivity in the halo region broadens significantly the Jsat profile, increasing the halo width at a similar total halo current
The Sachs-Wolfe Effect: Gauge Independence and a General Expression
In this paper we address two points concerning the Sachs-Wolfe effect: (i)
the gauge independence of the observable temperature anisotropy, and (ii) a
gauge-invariant expression of the effect considering the most general situation
of hydrodynamic perturbations. The first result follows because the gauge
transformation of the temperature fluctuation at the observation event only
contributes to the isotropic temperature change which, in practice, is absorbed
into the definition of the background temperature. Thus, we proceed without
fixing the gauge condition, and express the Sachs-Wolfe effect using the
gauge-invariant variables.Comment: 5 pages, closer to published versio
The No-defect Conjecture: Cosmological Implications
When the topology of the universe is non trivial, it has been shown that
there are constraints on the network of domain walls, cosmic strings and
monopoles. I generalize these results to textures and study the cosmological
implications of such constraints. I conclude that a large class of
multi-connected universes with topological defects accounting for structure
formation are ruled out by observation of the cosmic microwave background.Comment: 4 pages, 1 figure, accepted for publication as a brief report in
Phys. Rev.
HST/STIS spectroscopy of the exposed white dwarf in the short-period dwarf nova EK TrA
We present high resolution Hubble Space Telescope ultraviolet spectroscopy of
the dwarf nova EK TrA obtained in deep quiescence. The Space Telescope Imaging
Spectrograph data reveal the broad Ly-alpha absorption profile typical of a
moderately cool white dwarf, overlayed by numerous broad emission lines of He,
C, N, and Si and by a number of narrow absorption lines, mainly of CI and SiII.
Assuming a white dwarf mass in the range 0.3-1.4Msun we derive
Teff=17500-23400K for the primary in EK TrA; Teff=18800K for a canonical mass
of 0.6Msun. From the narrow photospheric absorption lines, we measure the white
dwarf rotational velocity, v*sin i=200+-100kms. Even though the strong
contamination of the photospheric white dwarf absorption spectrum by the
emission lines prevents a detailed quantitative analysis of the chemical
abundances of the atmosphere, the available data suggest slightly sub-solar
abundances. The high time resolution of the STIS data allows us to associate
the observed ultraviolet flickering with the emission lines, possibly
originating in a hot optically thin corona above the cold accretion disk.Comment: 6 pages A&A-Latex, 5 Figures, accepted for publication in A&
DT/T beyond linear theory
The major contribution to the anisotropy of the temperature of the Cosmic
Microwave Background (CMB) radiation is believed to come from the interaction
of linear density perturbations with the radiation previous to the decoupling
time. Assuming a standard thermal history for the gas after recombination, only
the gravitational field produced by the linear density perturbations present on
a universe can generate anisotropies at low z (these
anisotropies would manifest on large angular scales). However, secondary
anisotropies are inevitably produced during the nonlinear evolution of matter
at late times even in a universe with a standard thermal history. Two effects
associated to this nonlinear phase can give rise to new anisotropies: the
time-varying gravitational potential of nonlinear structures (Rees-Sciama RS
effect) and the inverse Compton scattering of the microwave photons with hot
electrons in clusters of galaxies (Sunyaev-Zeldovich SZ effect). These two
effects can produce distinct imprints on the CMB temperature anisotropy. We
discuss the amplitude of the anisotropies expected and the relevant angular
scales in different cosmological scenarios. Future sensitive experiments will
be able to probe the CMB anisotropies beyong the first order primary
contribution.Comment: plain tex, 16 pages, 3 figures. Proceedings of the Laredo Advance
School on Astrophysics "The universe at high-z, large-scale structure and the
cosmic microwave background". To be publised by Springer-Verla
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