2,714 research outputs found
Rome and the First Amendment of the Federal Constitution
This paper, however, merely intends to sound an alarm. Roman Catholicism, regardless of the impression it might give, is a genuine threat to the religious freedom guaranteed in the Federal Constitution. We shall not attempt to judge the validity of the American form of government. That we take for granted. But our purpose is this: to determine the extent of the liberty guaranteed in the law of the land; to point out apparent agreement and obvious discrepancies between liberty and the Vatican; and to cite the practice of Rome as evidence of her intolerance and the Papacy\u27s authoritarian principles
Numerical models for the circumstellar medium around Betelgeuse
The nearby red supergiant (RSG) Betelgeuse has a complex circumstellar medium
out to at least 0.5 parsecs from its surface, shaped by its mass-loss history
within the past 0.1 Myr, its environment, and its motion through the
interstellar medium (ISM). In principle its mass-loss history can be
constrained by comparing hydrodynamic models with observations. Observations
and numerical simulations indicate that Betelgeuse has a very young bow shock,
hence the star may have only recently become a RSG. To test this possibility we
calculated a stellar evolution model for a single star with properties
consistent with Betelgeuse. We incorporated the resulting evolving stellar wind
into 2D hydrodynamic simulations to model a runaway blue supergiant (BSG)
undergoing the transition to a RSG near the end of its life. The collapsing BSG
wind bubble induces a bow shock-shaped inner shell which at least superficially
resembles Betelgeuse's bow shock, and has a similar mass. Surrounding this is
the larger-scale retreating bow shock generated by the now defunct BSG wind's
interaction with the ISM. We investigate whether this outer shell could explain
the bar feature located (at least in projection) just in front of Betelgeuse's
bow shock.Comment: 5 pages, 3 figures; to appear in proceedings of the Betelgeuse 2012
Workshop, Paris, Nov. 201
Rolle des EAG-Kaliumkanals bei der Retinat-induzierten Differenzierung und Proliferationshemmung in humanen Neuroblastomzellen
Es kann unter Verwendung der Whole-cell-clamp Technik gezeigt werden, dass EAG-Ströme in verschiedenen Neuroblastomzelllinien unter Applikation von 13-cis- und all-trans-Retinat reduziert werden. Hierfür wurden mögliche Regulationsvorgänge untersucht. Es hat den Anschein, dass eine transkriptive Kontrolle der EAG-Kanäle durch Retinat vorliegt und dieser Kanal durch PI3-Kinasen beeinflusst werden kann. Gleichzeitig ist eine Induktion der Zelldifferenzierung und eine Proliferationshemmung in SH-SY5Y Zellen unter Retinat beobachtet wurden
Experimental quantum key distribution with simulated ground-to-satellite photon losses and processing limitations
Quantum key distribution (QKD) has the potential to improve communications
security by offering cryptographic keys whose security relies on the
fundamental properties of quantum physics. The use of a trusted quantum
receiver on an orbiting satellite is the most practical near-term solution to
the challenge of achieving long-distance (global-scale) QKD, currently limited
to a few hundred kilometers on the ground. This scenario presents unique
challenges, such as high photon losses and restricted classical data
transmission and processing power due to the limitations of a typical satellite
platform. Here we demonstrate the feasibility of such a system by implementing
a QKD protocol, with optical transmission and full post-processing, in the
high-loss regime using minimized computing hardware at the receiver. Employing
weak coherent pulses with decoy states, we demonstrate the production of secure
key bits at up to 56.5 dB of photon loss. We further illustrate the feasibility
of a satellite uplink by generating secure key while experimentally emulating
the varying channel losses predicted for realistic low-Earth-orbit satellite
passes at 600 km altitude. With a 76 MHz source and including finite-size
analysis, we extract 3374 bits of secure key from the best pass. We also
illustrate the potential benefit of combining multiple passes together: while
one suboptimal "upper-quartile" pass produces no finite-sized key with our
source, the combination of three such passes allows us to extract 165 bits of
secure key. Alternatively, we find that by increasing the signal rate to 300
MHz it would be possible to extract 21570 bits of secure finite-sized key in
just a single upper-quartile pass.Comment: 12 pages, 7 figures, 2 table
Cache-Oblivious Data Structures and Algorithms for Undirected Breadth-First Search and Shortest Paths
We present improved cache-oblivious data structures and algorithms for breadth-first search (BFS) on undirected graphs and the single-source shortest path (SSSP) problem on undirected graphs with non-negative edge weights. For the SSSP problem, our result closes the performance gap between the currently best cache-aware algorithm and the cache-oblivious counterpart. Our cache-oblivious SSSP-algorithm takes nearly full advantage of block transfers for dense graphs. The algorithm relies on a new data structure, called bucket heap, which is the first cache-oblivious priority queue to efficiently support a weak DECREASEKEY operation. For the BFS problem, we reduce the number of I/Os for sparse graphs by a factor of nearly sqrt{B}, where B is the cache-block size, nearly closing the performance gap between the currently best cache-aware and cache-oblivious algorithms
Osseointegration of zirconia implants compared with titanium : an in vivo study
Background Titanium and titanium alloys are widely used for fabrication of dental implants. Since the material composition and the surface topography of a biomaterial play a fundamental role in osseointegration, various chemical and physical surface modifications have been developed to improve osseous healing. Zirconia-based implants were introduced into dental implantology as an altenative to titanium implants. Zirconia seems to be a suitable implant material because of its tooth-like colour, its mechanical properties and its biocompatibility. As the osseointegration of zirconia implants has not been extensively investigated, the aim of this study was to compare the osseous healing of zirconia implants with titanium implants which have a roughened surface but otherwise similar implant geometries. Methods Forty-eight zirconia and titanium implants were introduced into the tibia of 12 minipigs. After 1, 4 or 12 weeks, animals were sacrificed and specimens containing the implants were examined in terms of histological and ultrastructural techniques. Results Histological results showed direct bone contact on the zirconia and titanium surfaces. Bone implant contact as measured by histomorphometry was slightly better on titanium than on zirconia surfaces. However, a statistically significant difference between the two groups was not observed. Conclusion The results demonstrated that zirconia implants with modified surfaces result in an osseointegration which is comparable with that of titanium implants
Identification of proteins in laser-microdissected small cell numbers by SELDI-TOF and Tandem MS
BACKGROUND: Laser microdissection allows precise isolation of specific cell types and compartments from complex tissues. To analyse proteins from small cell numbers, we combine laser-microdissection and manipulation (LMM) with mass spectrometry techniques. RESULTS: Hemalaun stained mouse lung sections were used to isolate 500–2,000 cells, enough material for complex protein profiles by SELDI-TOF MS (surface enhanced laser desorption and ionization/time of flight mass spectrometry), employing different chromatographic ProteinChip(® )Arrays. Initially, to establish the principle, we identified specific protein peaks from 20,000 laser-microdissected cells, combining column chromatography, SDS-PAGE, tryptic digestion, SELDI technology and Tandem MS/MS using a ProteinChip(® )Tandem MS Interface. Secondly, our aim was to reduce the labour requirements of microdissecting several thousand cells. Therefore, we first defined target proteins in a few microdissected cells, then recovered in whole tissue section homogenates from the same lung and applied to these analytical techniques. Both approaches resulted in a successful identification of the selected peaks. CONCLUSION: Laser-microdissection may thus be combined with SELDI-TOF MS for generation of protein marker profiles in a cell-type- or compartment-specific manner in complex tissues, linked with mass fingerprinting and peptide sequencing by Tandem MS/MS for definite characterization
Evaluation of evoked potentials to dyadic tones after cochlear implantation
Auditory evoked potentials are tools widely used to assess auditory cortex functions in clinical context. However, in cochlear implant users, electrophysiological measures are challenging due to implant-created artefacts in the EEG. Here, we used independent component analysis to reduce cochlear implant-related artefacts in event-related EEGs of cochlear implant users (n = 12), which allowed detailed spatio-temporal evaluation of auditory evoked potentials by means of dipole source analysis. The present study examined hemispheric asymmetries of auditory evoked potentials to musical sounds in cochlear implant users to evaluate the effect of this type of implantation on neuronal activity. In particular, implant users were presented with two dyadic tonal intervals in an active oddball design and in a passive listening condition. Principally, the results show that independent component analysis is an efficient approach that enables the study of neurophysiological mechanisms of restored auditory function in cochlear implant users. Moreover, our data indicate altered hemispheric asymmetries for dyadic tone processing in implant users compared with listeners with normal hearing (n = 12). We conclude that the evaluation of auditory evoked potentials are of major relevance to understanding auditory cortex function after cochlear implantation and could be of substantial clinical value by indicating the maturation/reorganization of the auditory system after implantatio
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