3,402 research outputs found
QCD Corrections to Vector-Boson Fusion Processes in Warped Higgsless Models
We discuss the signatures of a representative Higgsless model with ideal
fermion delocalization in vector-boson fusion processes, focusing on the gold-
and silver-plated decay modes of the gauge bosons at the CERN-Large Hadron
Collider. For this purpose, we have developed a fully-flexible parton-level
Monte-Carlo program, which allows for the calculation of cross sections and
kinematic distributions within experimentally feasible selection cuts at
NLO-QCD accuracy. We find that Kaluza-Klein resonances give rise to very
distinctive distributions of the decay leptons. Similar to the Standard Model
case, within the Higgsless scenario the perturbative treatment of the
vector-boson scattering processes is under excellent control.Comment: 22 pages, 20 figure
Screening for cardiac glycosides in Schizobasis intricata
Traditional herbalists in Natal use Schizobasis intricata (Bak.) Bak, as a substitute for Bowiea volubilis Harv. ex Hook. This may be due to morphological confusion of the two species or they may elicit a similar biological response. Bowiea bulbs are known to contain cardiac glycosides. A phytochemical screening of S. intricata for cardiac glycosides was carried out, S. intricata contains 2-deoxy sugars, common components in the sugar moieties of cardiac glycosides, Comparative chromatographic screening showed that S. intricata bulbs do not contain cardenolides nor any Bowiea-type bufadienolides. Other unknown bufadienolides may, however, be present In this plant
A user-friendly fully digital TDPAC-spectrometer
A user-friendly fully digital TDPAC-spectrometer with six detectors and fast digitizers using Field Programmable Gate Arrays is described and performance data are given
The Cosmic Crystallinity Conundrum: Clues from IRAS 17495-2534
Since their discovery, cosmic crystalline silicates have presented several
challenges to understanding dust formation and evolution. The mid-infrared
spectrum of IRAS 174952534, a highly obscured oxygen-rich asymptotic giant
branch (AGB) star, is the only source observed to date which exhibits a clear
crystalline silicate absorption feature. This provides an unprecedented
opportunity to test competing hypotheses for dust formation. Observed spectral
features suggest that both amorphous and crystalline dust is dominated by
forsterite (Mg\_2 SiO\_4) rather than enstatite (MgSiO\_3) or other silicate
compositions. We confirm that high mass-loss rates should produce more
crystalline material, and show why this should be dominated by forsterite. The
presence of Mg\_2 SiO\_4 glass suggests that another factor (possibly C/O) is
critical in determining astromineralogy. Correlation between crystallinity,
mass-loss rate and initial stellar mass suggests that only the most massive AGB
stars contribute significant quantities of crystalline material to the
interstellar medium, resolving the conundrum of its low crystallinity.Comment: 12 pages, 2 figure
Improving Monolithic Perovskite Silicon Tandem Solar Cells From an Optical Viewpoint
Perovskite silicon tandem solar cells are the most promising concept for a future photovoltaic technology. We report on recent progress from an optical viewpoint and disucss how we achieved more than 25 device efficienc
Antireflective nanotextures for monolithic perovskite silicon tandem solar cells
Recently, we studied the effect of hexagonal sinusoidal textures on the reflective properties of perovskite silicon tandem solar cells using the finite element method FEM . We saw that such nanotextures, applied to the perovskite top cell, can strongly increase the current density utilization from 91 for the optimized planar reference to 98 for the best nanotextured device period 500 nm and peak to valley height 500 nm , where 100 refers to the Tiedje Yablonovitch limit. [D. Chen et al., J. Photonics Energy 8, 022601, 2018 , doi 10.1117 1.JPE.8.022601] In this manuscript we elaborate on some numerical details of that work we validate an assumption based on the Tiedje Yablonovitch limit, we present a convergence study for simulations with the finite element method, and we compare different configurations for sinusoidal nanotexture
Significance of Nano- and Microtopography for Cell-Surface Interactions in Orthopaedic Implants
Cell-surface interactions play a crucial role for biomaterial application in orthopaedics.
It is evident that not only the chemical composition of solid substances influence cellular adherence,
migration, proliferation and differentiation but also the surface topography of a biomaterial.
The progressive application of nanostructured surfaces in medicine has gained increasing interest
to improve the cytocompatibility and osteointegration of orthopaedic implants. Therefore, the
understanding of cell-surface interactions is of major interest for these substances. In this review,
we elucidate the principle mechanisms of nano- and microscale cell-surface interactions in vitro for
different cell types onto typical orthopaedic biomaterials such as titanium (Ti),
cobalt-chrome-molybdenum (CoCrMo) alloys, stainless steel (SS), as well as synthetic polymers
(UHMWPE, XLPE, PEEK, PLLA). In addition, effects of nano- and microscaled particles and their
significance in orthopaedics were reviewed. The significance for the cytocompatibility
of nanobiomaterials is discussed critically
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