Analysis of OSO data to determine the structure and energy balance of the solar chromosphere

A detailed reexamination of the temperature-density structure of the photosphere and low chromosphere shows that the middle and upper chromosphere, which directly emits most of the OSO spectrum, is sensitive to conditions in this underlying region of the atmosphere. A model of this region is based on a unified compilation of all recently published broadband flux and central intensity observations of the solar spectrum from 500 microns in the far infrared to 1220 A in the far ultraviolet. This extensive compilation includes the OSO 4 and 6 observations in the wavelength range 1400 to 1220 A. A model is presented of the quiet solar atmosphere in the height range between the temperature minimum and the upper part of the chromosphere-corona transition region. This model is based on statistical equilibrium calculations of H, He 1, He 2, Si 1, C 1, and other ions

Matthew F. Maury School, 1934-1970: A case study in educational innovation

The investigation of Maury Elementary School in Richmond, Virginia addressed the establishment of a non-traditional model school in a conservative city not directly supportive or progressive education ideology. A case study approach was taken to investigate the interrelated questions of explaining the success and longevity of Maury School and of determining to what extent Maury School was a faithful implementation of the tenets of progressive education.;The study contributes to an understanding of the development of an innovative school, to progressive education, and to the diffusion and integration of educational theory and reform. Historical methodology was used; data were drawn from both published and unpublished primary and secondary sources and oral histories.;The progressive education movement was characterized by essential features and practices by which a school could be considered to be progressive. A description of the program developments at Maury revealed that the features of progressive education were established in the practical and philosophical functions of the school from 1934 until the school was closed in the summer of 1970.;The best explanation for the existence of Maury School was found to be an interrelated set of factors. The effective leadership of Principal Etta Rose Bailey was a key factor in the origin, development, and maintenance of the school. The long tenure of her principalship was a sustaining force in rooting and maintaining innovation. The school had an identity which separated it from the school system. The hierarchical structure of the system allowed the principal and the staff the autonomy to develop an innovative program. The innovations were not labeled as progressive education by the Maury staff, which enabled the program to outlive the movement itself. A unique culture was developed and sustained by the programs and practices.;From the case study of Maury Elementary School, where educational innovation was a local phenomenon limited to one school, inferences may be drawn regarding the effects of the progressive education reform movement in Richmond, Virginia. Additional study is recommended to determine if innovation can sustain itself without the continuity of strong leadership provided by a key figure at the location of the innovation

Time dependent effects at the foot of the chromosphere

A dynamical model was proposed which is in agreement with the observations that suggest the solar chromosphere is heated preferentially in magnetic regions. The dynamical model requires an energy flux that is large enough to lead to amplitudes for which the apparent temperatures match the empirical line temperatures in the UTV lines. Consistency with the observations of chromospheric emission then requires that the emission take place not uniformly over the solar surface but in smaller spatial regions

Adaptive User Perspective Rendering for Handheld Augmented Reality

Handheld Augmented Reality commonly implements some variant of magic lens rendering, which turns only a fraction of the user's real environment into AR while the rest of the environment remains unaffected. Since handheld AR devices are commonly equipped with video see-through capabilities, AR magic lens applications often suffer from spatial distortions, because the AR environment is presented from the perspective of the camera of the mobile device. Recent approaches counteract this distortion based on estimations of the user's head position, rendering the scene from the user's perspective. To this end, approaches usually apply face-tracking algorithms on the front camera of the mobile device. However, this demands high computational resources and therefore commonly affects the performance of the application beyond the already high computational load of AR applications. In this paper, we present a method to reduce the computational demands for user perspective rendering by applying lightweight optical flow tracking and an estimation of the user's motion before head tracking is started. We demonstrate the suitability of our approach for computationally limited mobile devices and we compare it to device perspective rendering, to head tracked user perspective rendering, as well as to fixed point of view user perspective rendering

The Effect of Inhomogeneities on High-Frequency, Low-1 p-Modes: DIFOS Experiment on CORONAS-I

The investigation of the effects of inhomogeneities of the acoustic modes of the global solar oscillation spectrum has two parts, the first dealing with the prediction of wave fluxes in magnetic flux tubes due to the excitation of longitudinal (i.e. pressure) modes, and the second part, concerning the effects of radiation damping on the p-modes themselves. Part 1 of this work, in collaboration with S.S. Hasan (Indian Institute of Astro- physics, Bangalore), is complete and has resulted in a publication titled Excitation of Longitudinal Modes in Solar Magnetic Flux Tubes, By S.S. Hasan & WK. It is in press in the ASP conference series, containing the proceedings of the Cool Stars conference of 1997, R.A. Donahue and J.A. Bookbinder, editors; publication is expected in 1998. Part 2, in collaboration with Y. Zhugzhda (Izmiran, Moscow) and J. Staude (Sonnenobservatorium Einsteinturm, Potsdam) is in progress and is expected to result in a paper in the forthcoming Boston conference on Helio- and Asteroseismology in June, 1998. A fuller accounting of the work done under the grant will be given when the work started with funding from the grant is complete

Die Aufgaben der Encyclopaedia Cinematographica im Spiegel ihres 40jährigen Bestehens : Arbeitsunterlage für die Redaktionsausschußtagung der Encyclopaedia Cinematographica, Göttingen, 5. - 9.10.1992

Arbeitsungsunterlage für die Redaktionsausschußtagung der ENCYCLOPAEDIA CINEMATOGRAPHICA. Göttingen, 5.-9.10.1992. H. Kalkofen, Inst. Wiss. Film. Während die ENCYCLOPAEDIA CINEMATOGRAPHICA nicht verbirgt, daß sie nun 40 Jahre alt geworden ist, kann sie auf die doch nicht ganz unziemliche Frage, wer sie denn überhaupt sei, keine einhellige Antwort geben. Es wird gezeigt, daß die EC im Lauf der Zeit ihres Bestehens verschiedene Selbst-Konzeptionen bekundet hat, die miteinander zum Teil vereinbart werden können, zum Teil aber nicht. Der prinzipielle Gegensatz zwischen dem sich, modelltheoretisch gesehen, durchaus nicht zu Unrecht als "Bewequnqspräparat" begreifenden Kinematogramm und dem die pure Deskription überschreitenden Film, dem es um die Vermittlung von Sinnzusammenhänqen geht, ließ sich nur in den Jahren der Gründungszeit bemanteln und verkennen. Es wird entschieden dafür plädiert, daß sich die ENCYCLOPAEDIA CINEMATOGRAPHICA auf ihre kinematographische Natur zurückbesinnt und sie weiterentwickelt. Andererseits scheint die Gründung eines internationalen Archivs wissenschaftlicher Filme aus mehreren Gründen erforderlich. Dieses Archiv, bei dessen Namensgebung auf das Epitheton /kinematographisch/ der K1arheit halber zu verzichten wäre, und die ENCYCLOPAEDIA CINEMATOGRAPHICA könnten sich, wiewohl eindeutig getrennt, gemeinsamer Infrastrukturen bedienen.Whereas the EC does not conceal that it has turned forty, it can give no clear answer to the not improper question of what it might happen to be. It shall be demonstrated that the EC has promulgated various self-concepts in the course of its existence, some of which are consistent with one another, while others are not. The fundamental discrepancy between the cinematogramme, which is -from a model-theoretical point of view -not wrongly understood to be a "movement specimen", and films transcending the boundaries of pure description, which are concerned to convey contexts of meaning, could still be concealed and misapprehended in the early years after the founding. This is decidedly a plea that the EC should recollect its cinematographic nature, and develop it further. On the other hand, the founding of an international archive of scientific films seems necessary for several reasons. This archive, the naming of which should, in the interest of clarity, eschew the epithet "cinematoqraphic", and the EC could, though wholly separate, make use of a common infrastructure

Small-scale structure and dynamics of the lower solar atmosphere

The chromosphere of the quiet Sun is a highly intermittent and dynamic phenomenon. Three-dimensional radiation (magneto-)hydrodynamic simulations exhibit a mesh-like pattern of hot shock fronts and cool expanding post-shock regions in the sub-canopy part of the inter-network. This domain might be called "fluctosphere". The pattern is produced by propagating shock waves, which are excited at the top of the convection zone and in the photospheric overshoot layer. New high-resolution observations reveal a ubiquitous small-scale pattern of bright structures and dark regions in-between. Although it qualitatively resembles the picture seen in models, more observations - e.g. with the future ALMA - are needed for thorough comparisons with present and future models. Quantitative comparisons demand for synthetic intensity maps and spectra for the three-dimensional (magneto-)hydrodynamic simulations. The necessary radiative transfer calculations, which have to take into account deviations from local thermodynamic equilibrium, are computationally very involved so that no reliable results have been produced so far. Until this task becomes feasible, we have to rely on careful qualitative comparisons of simulations and observations. Here we discuss what effects have to be considered for such a comparison. Nevertheless we are now on the verge of assembling a comprehensive picture of the solar chromosphere in inter-network regions as dynamic interplay of shock waves and structuring and guiding magnetic fields.Comment: 8 pages, 2 figures, to appear in the proceedings of the IAU Symposium No. 247, Waves & Oscillations in the Solar Atmosphere: Heating and Magneto-Seismology (Venezuela 2007