273 research outputs found
Entwicklung eines Verfahrens fĂŒr die Wirtschaftlichkeitsberechnung solarthermischer Anlagen: die LCOH Methode
An inexpensive nonlinear medium for intense ultrabroadband pulse characterization
The ability of pellets made up of compressed iron iodate nanocrystals to frequency-double the whole visible spectrum is demonstrated. We suggest their use for complete characterization of intense ultrabroadband laser pulse
New algorithms for adaptive optics point-spread function reconstruction
Context. The knowledge of the point-spread function compensated by adaptive
optics is of prime importance in several image restoration techniques such as
deconvolution and astrometric/photometric algorithms. Wavefront-related data
from the adaptive optics real-time computer can be used to accurately estimate
the point-spread function in adaptive optics observations. The only
point-spread function reconstruction algorithm implemented on astronomical
adaptive optics system makes use of particular functions, named .
These functions are derived from the mirror modes, and their number
is proportional to the square number of these mirror modes. Aims. We present
here two new algorithms for point-spread function reconstruction that aim at
suppressing the use of these functions to avoid the storage of a
large amount of data and to shorten the computation time of this PSF
reconstruction. Methods. Both algorithms take advantage of the eigen
decomposition of the residual parallel phase covariance matrix. In the first
algorithm, the use of a basis in which the latter matrix is diagonal reduces
the number of functions to the number of mirror modes. In the second
algorithm, this eigen decomposition is used to compute phase screens that
follow the same statistics as the residual parallel phase covariance matrix,
and thus suppress the need for these functions. Results. Our
algorithms dramatically reduce the number of functions to be computed
for the point-spread function reconstruction. Adaptive optics simulations show
the good accuracy of both algorithms to reconstruct the point-spread function.Comment: Accepte
Assembly of the Inner Perivitelline Layer, a Homo log of the Mammalian Zona Pellucida: An Immunohistochemical and Ultrastructural Study
The avian inner perivitelline layer (IPVL), a homologous structure to the mammalian zona pellucida, is deposited between the granulosa cells and the oocyte cell membrane during folliculogenesis. The glycoprotein meshwork of the IPVL forms a 3-dimensional matrix and possesses important functions in the fertilization process: it contributes to the binding of avian spermatozoa to the oocyte and induces acrosomal exocytosis. In contrast to the zona pellucida of mammals, the IPVL does not prevent the physiological polyspermy found in birds. Previous studies have shown that in the Japanese quail (Cotumix japonica) at least 5 glycoproteins are constituents of the IPVL (ZP1, ZP2, ZP3, ZP4, and ZPD). In this study, we investigated the spatiotennporal assembly pattern of the IPVL during folliculogenesis using immunohistochemical and ultrastructural methods. The obtained results clearly show that these glycoproteins are incorporated into the IPVL at distinct points during follicular development, supporting the hypothesis that ZP2 and ZP4 form a type of prematrix into which ZP1, ZP3, and ZPD are integrated at a later stage of development. Copyright (C) 2011 S. Karger AG, Base
The camera of the fifth H.E.S.S. telescope. Part I: System description
In July 2012, as the four ground-based gamma-ray telescopes of the H.E.S.S.
(High Energy Stereoscopic System) array reached their tenth year of operation
in Khomas Highlands, Namibia, a fifth telescope took its first data as part of
the system. This new Cherenkov detector, comprising a 614.5 m^2 reflector with
a highly pixelized camera in its focal plane, improves the sensitivity of the
current array by a factor two and extends its energy domain down to a few tens
of GeV.
The present part I of the paper gives a detailed description of the fifth
H.E.S.S. telescope's camera, presenting the details of both the hardware and
the software, emphasizing the main improvements as compared to previous
H.E.S.S. camera technology.Comment: 16 pages, 13 figures, accepted for publication in NIM
First events from the CNGS neutrino beam detected in the OPERA experiment
The OPERA neutrino detector at the underground Gran Sasso Laboratory (LNGS)
was designed to perform the first detection of neutrino oscillations in
appearance mode, through the study of nu_mu to nu_tau oscillations. The
apparatus consists of a lead/emulsion-film target complemented by electronic
detectors. It is placed in the high-energy, long-baseline CERN to LNGS beam
(CNGS) 730 km away from the neutrino source. In August 2006 a first run with
CNGS neutrinos was successfully conducted. A first sample of neutrino events
was collected, statistically consistent with the integrated beam intensity.
After a brief description of the beam and of the various sub-detectors, we
report on the achievement of this milestone, presenting the first data and some
analysis results.Comment: Submitted to the New Journal of Physic
Hot Very Small dust Grains in NGC 1068 seen in jet induced structures thanks to VLT/NACO adaptive optics
We present K, L and M diffraction-limited images of NGC 1068 obtained with
NAOS+CONICA at VLT/YEPUN over a 3.5" field around the central engine. Hot dust
(Tcol = 550-650 K) is found in three different regions : (a) in the true
nucleus, seen as a slightly NS elongated, core of extremely hot dust,
"resolved" in K and L with respective diameters of ~5 pc and 8.5 pc ; (b) along
the NS direction, as a "spiral arm" and a southern tongue ; (c) as a set of
parallel elongated nodules ("wave-like") bracketting the jet. Several
structures observed on radio maps, mid-IR or HST UV-visible maps are seen, so
that a precise registration can be done from UV to 6 cm. These results do
support the current interpretion that source (a) corresponds to emission from
dust near sublimation temperature delimiting the walls of the cavity in the
central obscuring torus. Structure (b) is thought to be a mixture of hot dust
and active star forming regions along a micro spiral structure that could trace
the tidal mechanism bringing matter to the central engine. Structure c)which
was not known, exhibits too high a temperature for "classical'' grains ; it is
most probably the signature of transiently heated very small dust grains (VSG)
: "nano-diamonds", which are resistant and can form in strong UV field or in
shocks, are very attractive candidates. The "waves'' can be condensations
triggered by jet induced shocks, as predicted by recent models. First
estimates, based on a simple VSG model and on a detailed radiative transfer
model, do agree with those interpretations, both qualitatively and
quantitatively.Comment: Submitted : 15 March 2003 ; accepted : 15 May 200
Characterization of Pseudomonas aeruginosa isolates: Occurrence rates, antimicrobial susceptibility patterns, and molecular typing in the global SENTRY Antimicrobial Surveillance Program, 1997-1999
During 1997â1999, a total of 70,067 isolates (6631 Pseudomonas aeruginosa isolates) were analyzed in the SENTRY program by geographic region and body site of infection. The respiratory tract was the most common source of P. aeruginosa. P. aeruginosa isolation rates increased during the study interval. Europe was the only region to show a significant decline in ÎČ-lactam and aminoglycoside susceptibility rates. There was a reduction in the rates of susceptibility of Canadian isolates to imipenem and of Latin American isolates to meropenem. A total of 218 multidrug-resistant P. aeruginosa isolates (MDR-PSA; resistant to piperacillin, ceftazidime, imipenem, and gentamicin) were observed; MDR-PSA occurrence rates (percentages of all isolates) ranged from 8.2% (Latin America) to 0.9% (Canada). No antimicrobial inhibited >50% of MDR-PSA strains. Molecular characterization of selected, generally resistant strains was performed. Isolates showing unique ribogroups were found in Europe, Latin America, and the United States, but clonal spread was documented in several medical centers.A. C. Gales, R. N. Jones, J. Turnidge, R. Rennie, and R. Rampha
Lower edge of locked Main Himalayan Thrust unzipped by the 2015 Gorkha earthquake
Large earthquakes are thought to release strain on previously locked faults. However, the details of how earthquakes are initiated, grow and terminate in relation to pre-seismically locked and creeping patches is unclear ^1-4. The 2015 Mw 7.8 Gorkha, Nepal earthquake occurred close to Kathmandu in a region where the prior pattern of fault locking is well documented ^5. Here we analyze this event using seismological records measured at teleseismic distances and Synthetic Aperture Radar imagery. We show that the earthquake originated northwest of Kathmandu within a cluster of background seismicity that fringes the bottom of the locked portion of the Main Himalayan Thrust fault (MHT). The rupture propagated eastwards for about 140 km, unzipping the lower edge of the locked portion of the fault. High-frequency seismic waves radiated continuously as the slip pulse propagated at about 2.8 km s-1 along this zone of presumably high and heterogeneous pre-ÂŹseismic stress at the seismic-aseismic transition. Eastward unzipping of the fault resumed during the Mw 7.3 aftershock on May 12. The transfer of stress to neighbouring regions during the Gorkha earthquake should facilitate future rupture of the areas of the MHT adjacent and up-dip of the Gorkha earthquake rupture.This is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/ngeo251
Killer immunoglobulin-like receptor and human leukocyte antigen-C genotypes in rheumatoid arthritis primary responders and non-responders to anti-TNF-α therapy
The identification of patients who will respond to anti-tumor necrosis factor alpha (anti-TNF-α) therapy will improve the efficacy, safety, and economic impact of these agents. We investigated whether killer cell immunoglobulin-like receptor (KIR) genes are related to response to anti-TNF-α therapy in patients with rheumatoid arthritis (RA). Sixty-four RA patients and 100 healthy controls were genotyped for 16 KIR genes and human leukocyte antigen-C (HLA-C) group 1/2 using polymerase chain reaction sequence-specific oligonucleotide probes (PCR-SSOP). Each patient received anti-TNF-α therapy (adalimumab, etanercept, or infliximab), and clinical responses were evaluated after 3 months using the disease activity score in 28 joints (DAS28). We investigated the correlations between the carriership of KIR genes, HLA-C group 1/2 genes, and clinical data with response to therapy. Patients responding to therapy showed a significantly higher frequency of KIR2DS2/KIR2DL2 (67.7% R vs. 33.3% NR; P = 0.012). A positive clinical outcome was associated with an activating KIRâHLA genotype; KIR2DS2(+)HLA-C group 1/2 homozygous. Inversely, non-response was associated with the relatively inhibitory KIR2DS2(â)HLA-C group 1/2 heterozygous genotype. The KIR and HLA-C genotype of an RA patient may provide predictive information for response to anti-TNF-α therapy
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