171 research outputs found
"Libussa" in der Gründerzeit : Grillparzer zwischen Kürnberger und Heine
Am Beginn der siebziger Jahre des 19. Jahrhunderts schrieb Ferdinand Kürnberger zwei Feuilletons zu Franz Grillparzer. Diese Feuilletons aus der 'Gründerzeit' verdrängen die entscheidenden Fragen, die Grillparzer mit Heinrich Heine und Rahel Varnhagen verbunden haben: die Frage der Marginalisierung der Poesie in einer von Naturverwertung und instrumenteller Vernunft bestimmten Welt, die Frage einer gleichberechtigten Beziehung der Geschlechter zueinander und das Schicksal der Liebe in einer Zeit umfassender Rationalisierung und Verwertung
A spatial light modulator using BSO crystals
The combined use of the photoelectric and electro-optic properties of the Bi12SiO20 (BSO)-crystal leads to a new possibility of realizing a spatial light modulator. Under certain geometrical conditions, which will be discussed, it is possible to realize, that the BSO-crystal becomes birefringent depending on the local illuminance; the physical connection between the distributions of birefringence and illuminance will be shown. The BSO-crystal combined with a polarizer setup works as a spatial light modulator or as an incoherent to coherent converter
New light valve based in photoinduced space charge fields in BSO-crystals
The combined photoelectric and electrooptic properties of the BSO-crystal lead to a new possibility of realizing a real time spatial light modulator. Under certain geometrical conditions the crystal becomes birefringent in dependence on the local illuminance. Together with a suitable polarizer setup the crystal works as well as an incoherent to coherent converter as for contrast inversion
Differential diagnosis of laryngeal spindle cell carcinoma and inflammatory myofibroblastic tumor – report of two cases with similar morphology
BACKGROUND: Spindle cell tumors of the larynx are rare. In some cases, the dignity is difficult to determine. We report two cases of laryngeal spindle cell tumors. CASE PRESENTATION: Case 1 is a spindle cell carcinoma (SPC) in a 55 year-old male patient and case 2 an inflammatory myofibroblastic tumor (IMT) in a 34 year-old female patient. A comprehensive morphological and immunohistochemical analysis was done. Both tumors arose at the vocal folds. Magnified laryngoscopy showed polypoid tumors. After resection, conventional histological investigation revealed spindle cell lesions with similar morphology. We found ulceration, mild atypia, and myxoid stroma. Before immunohistochemistry, the dignity was uncertain. Immunohistochemical investigations led to diagnosis of two distinct tumors with different biological behaviour. Both expressed vimentin. Furthermore, the SPC was positive for pan-cytokeratin AE1/3, CK5/6, and smooth-muscle actin, whereas the IMT reacted with antibodies against ALK-1, and EMA. The proliferation (Ki67) was up to 80% in SPC and 10% in IMT. Other stainings with antibodies against p53, p21, Cyclin D1, or Rb did not result in additional information. After resection, the patient with SPC is free of disease for seven months. The IMT recurred three months after first surgery, but no relapses were found eight months after resurgery. CONCLUSION: Differential diagnosis can be difficult without immunohistochemistry. Therefore, a comprehensive morphological and immunohistochemical analysis is necessary, but markers of cell cycle (apart from the assessment of proliferation) do not help
Multi-Sensor Field Studies of Lightning and Implications for MTG-LI
Future geostationary satellite systems will offer a variety of improved observing capabilities which will be
extremely useful for many applications like numerical weather forecasting, nowcasting of severe weather,
climate research or hydrology. The planning for MTG (Meteosat Third Generation) includes an optical
lightning imager (LI) as part of the payload. One requirement for a proper interpretation of these optical
data is a better understanding of what components of a flash are to be seen from space and how these
observations relate to ground based radio frequency observations. Therefore, the objectives of the present
study concern the improvement of the understanding of the complex lightning process which then enables
a proper interpretation of the optical data.
For assessing the future performances and benefits of a geostationary lightning sensor this study takes
advantage of the comprehensive lightning data sets obtained from the recent CHUVA field experiment
performed in Brazil. (CHUVA - Cloud processes of tHe main precipitation systems in Brazil: A contribUtion
to cloud resolVing modeling and to the GPM (GlobAl Precipitation Measurement)). During the rainy season
of 2011-2012 a large number of ground based lightning detection systems was set up in the Sao Paulo
area in Brazil. In the present study we look at the detailed radio frequency (RF) based observation from
LINET (Lightning detection network operated by DLR, nowcast and USP) and observing strokes in the
VLF/LF (very low and low frequency) range, the LMA (Lightning mapping array) from NASA observing RF
sources in the VHF (very high frequency) range and the TRMM-LIS (Tropical Rainfall Measuring
Mission-Lightning Imaging Sensor) optical space borne lightning imager. The LIS is used as a reference
instrument for the future MTG-LI sensor as well as for the corresponding GLM sensor (Geostationary
Lightning Mapper) on GOES-R. Thus it is possible to study the relations between the RF and optical
signals from lightning in detail and to assess the performance of the future geostationary observations from
a set of proxy satellite data generated from the ground based observations.
In confirmation of previous studies, it was found that often a direct temporal coincidence of RF
signals (LINET strokes) and optical pulses (LIS groups) exists. The short baseline configuration
of LINET allowed to observe the strokes mapping the flash branches similar to LMA, but by
locating the limited number of strong cloud strokes rather than a large number of weak source
points from leader steps. An initial breakdown phase of vertically propagating sources can often
be found in LINET and LMA data. The higher level LINET and LMA signals have higher
probability to be optically detected. Lower level LINET and LMA signals are optically detected
from above in case of missing high level precipitation as inferred from radar observations
provided by USP. The new comprehensive data set allows for constructing proxy data for the
future geostationary lightning mappers
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